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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* vim: set ts=8 sts=2 et sw=2 tw=80:
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
/*
* JS bytecode generation.
*/
#include "frontend/BytecodeEmitter.h"
#include "mozilla/Casting.h" // mozilla::AssertedCast
#include "mozilla/DebugOnly.h" // mozilla::DebugOnly
#include "mozilla/FloatingPoint.h" // mozilla::NumberEqualsInt32, mozilla::NumberIsInt32
#include "mozilla/HashTable.h" // mozilla::HashSet
#include "mozilla/Maybe.h" // mozilla::{Maybe,Nothing,Some}
#include "mozilla/PodOperations.h" // mozilla::PodCopy
#include "mozilla/Saturate.h"
#include "mozilla/Variant.h" // mozilla::AsVariant
#include <algorithm>
#include <iterator>
#include <string.h>
#include "jstypes.h" // JS_BIT
#include "frontend/AbstractScopePtr.h" // ScopeIndex
#include "frontend/BytecodeControlStructures.h" // NestableControl, BreakableControl, LabelControl, LoopControl, TryFinallyControl
#include "frontend/CallOrNewEmitter.h" // CallOrNewEmitter
#include "frontend/CForEmitter.h" // CForEmitter
#include "frontend/DecoratorEmitter.h" // DecoratorEmitter
#include "frontend/DefaultEmitter.h" // DefaultEmitter
#include "frontend/DoWhileEmitter.h" // DoWhileEmitter
#include "frontend/ElemOpEmitter.h" // ElemOpEmitter
#include "frontend/EmitterScope.h" // EmitterScope
#include "frontend/ExpressionStatementEmitter.h" // ExpressionStatementEmitter
#include "frontend/ForInEmitter.h" // ForInEmitter
#include "frontend/ForOfEmitter.h" // ForOfEmitter
#include "frontend/FunctionEmitter.h" // FunctionEmitter, FunctionScriptEmitter, FunctionParamsEmitter
#include "frontend/IfEmitter.h" // IfEmitter, InternalIfEmitter, CondEmitter
#include "frontend/LabelEmitter.h" // LabelEmitter
#include "frontend/LexicalScopeEmitter.h" // LexicalScopeEmitter
#include "frontend/ModuleSharedContext.h" // ModuleSharedContext
#include "frontend/NameAnalysisTypes.h" // PrivateNameKind
#include "frontend/NameFunctions.h" // NameFunctions
#include "frontend/NameOpEmitter.h" // NameOpEmitter
#include "frontend/ObjectEmitter.h" // PropertyEmitter, ObjectEmitter, ClassEmitter
#include "frontend/OptionalEmitter.h" // OptionalEmitter
#include "frontend/ParseContext.h" // ParseContext::Scope
#include "frontend/ParseNode.h" // ParseNodeKind, ParseNode and subclasses
#include "frontend/Parser.h" // Parser
#include "frontend/ParserAtom.h" // ParserAtomsTable, ParserAtom
#include "frontend/PrivateOpEmitter.h" // PrivateOpEmitter
#include "frontend/PropOpEmitter.h" // PropOpEmitter
#include "frontend/SourceNotes.h" // SrcNote, SrcNoteType, SrcNoteWriter
#include "frontend/SwitchEmitter.h" // SwitchEmitter
#include "frontend/TaggedParserAtomIndexHasher.h" // TaggedParserAtomIndexHasher
#include "frontend/TDZCheckCache.h" // TDZCheckCache
#include "frontend/TryEmitter.h" // TryEmitter
#include "frontend/WhileEmitter.h" // WhileEmitter
#include "js/ColumnNumber.h" // JS::LimitedColumnNumberOneOrigin, JS::ColumnNumberOffset
#include "js/friend/ErrorMessages.h" // JSMSG_*
#include "js/friend/StackLimits.h" // AutoCheckRecursionLimit
#include "util/StringBuffer.h" // StringBuffer
#include "vm/BytecodeUtil.h" // JOF_*, IsArgOp, IsLocalOp, SET_UINT24, SET_ICINDEX, BytecodeFallsThrough, BytecodeIsJumpTarget
#include "vm/CompletionKind.h" // CompletionKind
#include "vm/FunctionPrefixKind.h" // FunctionPrefixKind
#include "vm/GeneratorObject.h" // AbstractGeneratorObject
#include "vm/Opcodes.h" // JSOp, JSOpLength_*
#include "vm/PropMap.h" // SharedPropMap::MaxPropsForNonDictionary
#include "vm/Scope.h" // GetScopeDataTrailingNames
#include "vm/SharedStencil.h" // ScopeNote
#include "vm/ThrowMsgKind.h" // ThrowMsgKind
using namespace js;
using namespace js::frontend;
using mozilla::AssertedCast;
using mozilla::AsVariant;
using mozilla::DebugOnly;
using mozilla::Maybe;
using mozilla::Nothing;
using mozilla::NumberEqualsInt32;
using mozilla::NumberIsInt32;
using mozilla::PodCopy;
using mozilla::Some;
static bool ParseNodeRequiresSpecialLineNumberNotes(ParseNode* pn) {
// The few node types listed below are exceptions to the usual
// location-source-note-emitting code in BytecodeEmitter::emitTree().
// Single-line `while` loops and C-style `for` loops require careful
// handling to avoid strange stepping behavior.
ParseNodeKind kind = pn->getKind();
return kind == ParseNodeKind::WhileStmt || kind == ParseNodeKind::ForStmt ||
kind == ParseNodeKind::Function;
}
static bool NeedsFieldInitializer(ParseNode* member, bool inStaticContext) {
// For the purposes of bytecode emission, StaticClassBlocks are treated as if
// they were static initializers.
return (member->is<StaticClassBlock>() && inStaticContext) ||
(member->is<ClassField>() &&
member->as<ClassField>().isStatic() == inStaticContext);
}
static bool NeedsAccessorInitializer(ParseNode* member, bool isStatic) {
if (isStatic) {
return false;
}
return member->is<ClassMethod>() &&
member->as<ClassMethod>().name().isKind(ParseNodeKind::PrivateName) &&
!member->as<ClassMethod>().isStatic() &&
member->as<ClassMethod>().accessorType() != AccessorType::None;
}
static bool ShouldSuppressBreakpointsAndSourceNotes(
SharedContext* sc, BytecodeEmitter::EmitterMode emitterMode) {
// Suppress for all self-hosting code.
if (emitterMode == BytecodeEmitter::EmitterMode::SelfHosting) {
return true;
}
// Suppress for synthesized class constructors.
if (sc->isFunctionBox()) {
FunctionBox* funbox = sc->asFunctionBox();
return funbox->isSyntheticFunction() && funbox->isClassConstructor();
}
return false;
}
BytecodeEmitter::BytecodeEmitter(BytecodeEmitter* parent, FrontendContext* fc,
SharedContext* sc,
const ErrorReporter& errorReporter,
CompilationState& compilationState,
EmitterMode emitterMode)
: sc(sc),
fc(fc),
parent(parent),
bytecodeSection_(fc, sc->extent().lineno,
JS::LimitedColumnNumberOneOrigin(sc->extent().column)),
perScriptData_(fc, compilationState),
errorReporter_(errorReporter),
compilationState(compilationState),
suppressBreakpointsAndSourceNotes(
ShouldSuppressBreakpointsAndSourceNotes(sc, emitterMode)),
emitterMode(emitterMode) {
MOZ_ASSERT_IF(parent, fc == parent->fc);
}
BytecodeEmitter::BytecodeEmitter(BytecodeEmitter* parent, SharedContext* sc)
: BytecodeEmitter(parent, parent->fc, sc, parent->errorReporter_,
parent->compilationState, parent->emitterMode) {}
BytecodeEmitter::BytecodeEmitter(FrontendContext* fc,
const EitherParser& parser, SharedContext* sc,
CompilationState& compilationState,
EmitterMode emitterMode)
: BytecodeEmitter(nullptr, fc, sc, parser.errorReporter(), compilationState,
emitterMode) {
ep_.emplace(parser);
}
void BytecodeEmitter::initFromBodyPosition(TokenPos bodyPosition) {
setScriptStartOffsetIfUnset(bodyPosition.begin);
setFunctionBodyEndPos(bodyPosition.end);
}
bool BytecodeEmitter::init() {
if (!parent) {
if (!compilationState.prepareSharedDataStorage(fc)) {
return false;
}
}
return perScriptData_.init(fc);
}
bool BytecodeEmitter::init(TokenPos bodyPosition) {
initFromBodyPosition(bodyPosition);
return init();
}
template <typename T>
T* BytecodeEmitter::findInnermostNestableControl() const {
return NestableControl::findNearest<T>(innermostNestableControl);
}
template <typename T, typename Predicate /* (T*) -> bool */>
T* BytecodeEmitter::findInnermostNestableControl(Predicate predicate) const {
return NestableControl::findNearest<T>(innermostNestableControl, predicate);
}
NameLocation BytecodeEmitter::lookupName(TaggedParserAtomIndex name) {
return innermostEmitterScope()->lookup(this, name);
}
void BytecodeEmitter::lookupPrivate(TaggedParserAtomIndex name,
NameLocation& loc,
Maybe<NameLocation>& brandLoc) {
innermostEmitterScope()->lookupPrivate(this, name, loc, brandLoc);
}
Maybe<NameLocation> BytecodeEmitter::locationOfNameBoundInScope(
TaggedParserAtomIndex name, EmitterScope* target) {
return innermostEmitterScope()->locationBoundInScope(name, target);
}
template <typename T>
Maybe<NameLocation> BytecodeEmitter::locationOfNameBoundInScopeType(
TaggedParserAtomIndex name, EmitterScope* source) {
EmitterScope* aScope = source;
while (!aScope->scope(this).is<T>()) {
aScope = aScope->enclosingInFrame();
}
return source->locationBoundInScope(name, aScope);
}
bool BytecodeEmitter::markStepBreakpoint() {
if (skipBreakpointSrcNotes()) {
return true;
}
if (!newSrcNote(SrcNoteType::BreakpointStepSep)) {
return false;
}
// We track the location of the most recent separator for use in
// markSimpleBreakpoint. Note that this means that the position must already
// be set before markStepBreakpoint is called.
bytecodeSection().updateSeparatorPosition();
return true;
}
bool BytecodeEmitter::markSimpleBreakpoint() {
if (skipBreakpointSrcNotes()) {
return true;
}
// If a breakable call ends up being the same location as the most recent
// expression start, we need to skip marking it breakable in order to avoid
// having two breakpoints with the same line/column position.
// Note: This assumes that the position for the call has already been set.
if (!bytecodeSection().isDuplicateLocation()) {
if (!newSrcNote(SrcNoteType::Breakpoint)) {
return false;
}
}
return true;
}
bool BytecodeEmitter::emitCheck(JSOp op, ptrdiff_t delta,
BytecodeOffset* offset) {
size_t oldLength = bytecodeSection().code().length();
*offset = BytecodeOffset(oldLength);
size_t newLength = oldLength + size_t(delta);
if (MOZ_UNLIKELY(newLength > MaxBytecodeLength)) {
ReportAllocationOverflow(fc);
return false;
}
if (!bytecodeSection().code().growByUninitialized(delta)) {
return false;
}
if (BytecodeOpHasIC(op)) {
// Even if every bytecode op is a JOF_IC op and the function has ARGC_LIMIT
// arguments, numICEntries cannot overflow.
static_assert(MaxBytecodeLength + 1 /* this */ + ARGC_LIMIT <= UINT32_MAX,
"numICEntries must not overflow");
bytecodeSection().incrementNumICEntries();
}
return true;
}
#ifdef DEBUG
bool BytecodeEmitter::checkStrictOrSloppy(JSOp op) {
if (IsCheckStrictOp(op) && !sc->strict()) {
return false;
}
if (IsCheckSloppyOp(op) && sc->strict()) {
return false;
}
return true;
}
#endif
bool BytecodeEmitter::emit1(JSOp op) {
MOZ_ASSERT(checkStrictOrSloppy(op));
BytecodeOffset offset;
if (!emitCheck(op, 1, &offset)) {
return false;
}
jsbytecode* code = bytecodeSection().code(offset);
code[0] = jsbytecode(op);
bytecodeSection().updateDepth(op, offset);
return true;
}
bool BytecodeEmitter::emit2(JSOp op, uint8_t op1) {
MOZ_ASSERT(checkStrictOrSloppy(op));
BytecodeOffset offset;
if (!emitCheck(op, 2, &offset)) {
return false;
}
jsbytecode* code = bytecodeSection().code(offset);
code[0] = jsbytecode(op);
code[1] = jsbytecode(op1);
bytecodeSection().updateDepth(op, offset);
return true;
}
bool BytecodeEmitter::emit3(JSOp op, jsbytecode op1, jsbytecode op2) {
MOZ_ASSERT(checkStrictOrSloppy(op));
/* These should filter through emitVarOp. */
MOZ_ASSERT(!IsArgOp(op));
MOZ_ASSERT(!IsLocalOp(op));
BytecodeOffset offset;
if (!emitCheck(op, 3, &offset)) {
return false;
}
jsbytecode* code = bytecodeSection().code(offset);
code[0] = jsbytecode(op);
code[1] = op1;
code[2] = op2;
bytecodeSection().updateDepth(op, offset);
return true;
}
bool BytecodeEmitter::emitN(JSOp op, size_t extra, BytecodeOffset* offset) {
MOZ_ASSERT(checkStrictOrSloppy(op));
ptrdiff_t length = 1 + ptrdiff_t(extra);
BytecodeOffset off;
if (!emitCheck(op, length, &off)) {
return false;
}
jsbytecode* code = bytecodeSection().code(off);
code[0] = jsbytecode(op);
/* The remaining |extra| bytes are set by the caller */
/*
* Don't updateDepth if op's use-count comes from the immediate
* operand yet to be stored in the extra bytes after op.
*/
if (CodeSpec(op).nuses >= 0) {
bytecodeSection().updateDepth(op, off);
}
if (offset) {
*offset = off;
}
return true;
}
bool BytecodeEmitter::emitJumpTargetOp(JSOp op, BytecodeOffset* off) {
MOZ_ASSERT(BytecodeIsJumpTarget(op));
// Record the current IC-entry index at start of this op.
uint32_t numEntries = bytecodeSection().numICEntries();
size_t n = GetOpLength(op) - 1;
MOZ_ASSERT(GetOpLength(op) >= 1 + ICINDEX_LEN);
if (!emitN(op, n, off)) {
return false;
}
SET_ICINDEX(bytecodeSection().code(*off), numEntries);
return true;
}
bool BytecodeEmitter::emitJumpTarget(JumpTarget* target) {
BytecodeOffset off = bytecodeSection().offset();
// Alias consecutive jump targets.
if (bytecodeSection().lastTargetOffset().valid() &&
off == bytecodeSection().lastTargetOffset() +
BytecodeOffsetDiff(JSOpLength_JumpTarget)) {
target->offset = bytecodeSection().lastTargetOffset();
return true;
}
target->offset = off;
bytecodeSection().setLastTargetOffset(off);
BytecodeOffset opOff;
return emitJumpTargetOp(JSOp::JumpTarget, &opOff);
}
bool BytecodeEmitter::emitJumpNoFallthrough(JSOp op, JumpList* jump) {
BytecodeOffset offset;
if (!emitCheck(op, 5, &offset)) {
return false;
}
jsbytecode* code = bytecodeSection().code(offset);
code[0] = jsbytecode(op);
MOZ_ASSERT(!jump->offset.valid() ||
(0 <= jump->offset.value() && jump->offset < offset));
jump->push(bytecodeSection().code(BytecodeOffset(0)), offset);
bytecodeSection().updateDepth(op, offset);
return true;
}
bool BytecodeEmitter::emitJump(JSOp op, JumpList* jump) {
if (!emitJumpNoFallthrough(op, jump)) {
return false;
}
if (BytecodeFallsThrough(op)) {
JumpTarget fallthrough;
if (!emitJumpTarget(&fallthrough)) {
return false;
}
}
return true;
}
void BytecodeEmitter::patchJumpsToTarget(JumpList jump, JumpTarget target) {
MOZ_ASSERT(
!jump.offset.valid() ||
(0 <= jump.offset.value() && jump.offset <= bytecodeSection().offset()));
MOZ_ASSERT(0 <= target.offset.value() &&
target.offset <= bytecodeSection().offset());
MOZ_ASSERT_IF(
jump.offset.valid() &&
target.offset + BytecodeOffsetDiff(4) <= bytecodeSection().offset(),
BytecodeIsJumpTarget(JSOp(*bytecodeSection().code(target.offset))));
jump.patchAll(bytecodeSection().code(BytecodeOffset(0)), target);
}
bool BytecodeEmitter::emitJumpTargetAndPatch(JumpList jump) {
if (!jump.offset.valid()) {
return true;
}
JumpTarget target;
if (!emitJumpTarget(&target)) {
return false;
}
patchJumpsToTarget(jump, target);
return true;
}
bool BytecodeEmitter::emitCall(JSOp op, uint16_t argc,
const Maybe<uint32_t>& sourceCoordOffset) {
if (sourceCoordOffset.isSome()) {
if (!updateSourceCoordNotes(*sourceCoordOffset)) {
return false;
}
}
return emit3(op, ARGC_LO(argc), ARGC_HI(argc));
}
bool BytecodeEmitter::emitCall(JSOp op, uint16_t argc, ParseNode* pn) {
return emitCall(op, argc, pn ? Some(pn->pn_pos.begin) : Nothing());
}
bool BytecodeEmitter::emitDupAt(unsigned slotFromTop, unsigned count) {
MOZ_ASSERT(slotFromTop < unsigned(bytecodeSection().stackDepth()));
MOZ_ASSERT(slotFromTop + 1 >= count);
if (slotFromTop == 0 && count == 1) {
return emit1(JSOp::Dup);
}
if (slotFromTop == 1 && count == 2) {
return emit1(JSOp::Dup2);
}
if (slotFromTop >= Bit(24)) {
reportError(nullptr, JSMSG_TOO_MANY_LOCALS);
return false;
}
for (unsigned i = 0; i < count; i++) {
BytecodeOffset off;
if (!emitN(JSOp::DupAt, 3, &off)) {
return false;
}
jsbytecode* pc = bytecodeSection().code(off);
SET_UINT24(pc, slotFromTop);
}
return true;
}
bool BytecodeEmitter::emitPopN(unsigned n) {
MOZ_ASSERT(n != 0);
if (n == 1) {
return emit1(JSOp::Pop);
}
// 2 JSOp::Pop instructions (2 bytes) are shorter than JSOp::PopN (3 bytes).
if (n == 2) {
return emit1(JSOp::Pop) && emit1(JSOp::Pop);
}
return emitUint16Operand(JSOp::PopN, n);
}
bool BytecodeEmitter::emitPickN(uint8_t n) {
MOZ_ASSERT(n != 0);
if (n == 1) {
return emit1(JSOp::Swap);
}
return emit2(JSOp::Pick, n);
}
bool BytecodeEmitter::emitUnpickN(uint8_t n) {
MOZ_ASSERT(n != 0);
if (n == 1) {
return emit1(JSOp::Swap);
}
return emit2(JSOp::Unpick, n);
}
bool BytecodeEmitter::emitCheckIsObj(CheckIsObjectKind kind) {
return emit2(JSOp::CheckIsObj, uint8_t(kind));
}
bool BytecodeEmitter::emitBuiltinObject(BuiltinObjectKind kind) {
return emit2(JSOp::BuiltinObject, uint8_t(kind));
}
/* Updates line number notes, not column notes. */
bool BytecodeEmitter::updateLineNumberNotes(uint32_t offset) {
if (skipLocationSrcNotes()) {
return true;
}
const ErrorReporter& er = errorReporter();
std::optional<bool> onThisLineStatus =
er.isOnThisLine(offset, bytecodeSection().currentLine());
if (!onThisLineStatus.has_value()) {
er.errorNoOffset(JSMSG_OUT_OF_MEMORY);
return false;
}
bool onThisLine = *onThisLineStatus;
if (!onThisLine) {
unsigned line = er.lineAt(offset);
unsigned delta = line - bytecodeSection().currentLine();
// If we use a `SetLine` note below, we want it to be relative to the
// scripts initial line number for better chance of sharing.
unsigned initialLine = sc->extent().lineno;
MOZ_ASSERT(line >= initialLine);
/*
* Encode any change in the current source line number by using
* either several SrcNoteType::NewLine notes or just one
* SrcNoteType::SetLine note, whichever consumes less space.
*
* NB: We handle backward line number deltas (possible with for
* loops where the update part is emitted after the body, but its
* line number is <= any line number in the body) here by letting
* unsigned delta_ wrap to a very large number, which triggers a
* SrcNoteType::SetLine.
*/
bytecodeSection().setCurrentLine(line, offset);
if (delta >= SrcNote::SetLine::lengthFor(line, initialLine)) {
if (!newSrcNote2(SrcNoteType::SetLine,
SrcNote::SetLine::toOperand(line, initialLine))) {
return false;
}
} else {
do {
if (!newSrcNote(SrcNoteType::NewLine)) {
return false;
}
} while (--delta != 0);
}
bytecodeSection().updateSeparatorPositionIfPresent();
}
return true;
}
/* Updates the line number and column number information in the source notes. */
bool BytecodeEmitter::updateSourceCoordNotes(uint32_t offset) {
if (skipLocationSrcNotes()) {
return true;
}
if (!updateLineNumberNotes(offset)) {
return false;
}
JS::LimitedColumnNumberOneOrigin columnIndex =
errorReporter().columnAt(offset);
// Assert colspan is always representable.
static_assert((0 - ptrdiff_t(JS::LimitedColumnNumberOneOrigin::Limit)) >=
SrcNote::ColSpan::MinColSpan);
static_assert((ptrdiff_t(JS::LimitedColumnNumberOneOrigin::Limit) - 0) <=
SrcNote::ColSpan::MaxColSpan);
JS::ColumnNumberOffset colspan = columnIndex - bytecodeSection().lastColumn();
if (colspan != JS::ColumnNumberOffset::zero()) {
if (lastLineOnlySrcNoteIndex != LastSrcNoteIsNotLineOnly) {
MOZ_ASSERT(bytecodeSection().lastColumn() ==
JS::LimitedColumnNumberOneOrigin());
const SrcNotesVector& notes = bytecodeSection().notes();
SrcNoteType type = notes[lastLineOnlySrcNoteIndex].type();
if (type == SrcNoteType::NewLine) {
if (!convertLastNewLineToNewLineColumn(columnIndex)) {
return false;
}
} else {
MOZ_ASSERT(type == SrcNoteType::SetLine);
if (!convertLastSetLineToSetLineColumn(columnIndex)) {
return false;
}
}
} else {
if (!newSrcNote2(SrcNoteType::ColSpan,
SrcNote::ColSpan::toOperand(colspan))) {
return false;
}
}
bytecodeSection().setLastColumn(columnIndex, offset);
bytecodeSection().updateSeparatorPositionIfPresent();
}
return true;
}
bool BytecodeEmitter::updateSourceCoordNotesIfNonLiteral(ParseNode* node) {
if (node->isLiteral()) {
return true;
}
return updateSourceCoordNotes(node->pn_pos.begin);
}
uint32_t BytecodeEmitter::getOffsetForLoop(ParseNode* nextpn) {
// Try to give the JSOp::LoopHead the same line number as the next
// instruction. nextpn is often a block, in which case the next instruction
// typically comes from the first statement inside.
if (nextpn->is<LexicalScopeNode>()) {
nextpn = nextpn->as<LexicalScopeNode>().scopeBody();
}
if (nextpn->isKind(ParseNodeKind::StatementList)) {
if (ParseNode* firstStatement = nextpn->as<ListNode>().head()) {
nextpn = firstStatement;
}
}
return nextpn->pn_pos.begin;
}
bool BytecodeEmitter::emitUint16Operand(JSOp op, uint32_t operand) {
MOZ_ASSERT(operand <= UINT16_MAX);
if (!emit3(op, UINT16_LO(operand), UINT16_HI(operand))) {
return false;
}
return true;
}
bool BytecodeEmitter::emitUint32Operand(JSOp op, uint32_t operand) {
BytecodeOffset off;
if (!emitN(op, 4, &off)) {
return false;
}
SET_UINT32(bytecodeSection().code(off), operand);
return true;
}
bool BytecodeEmitter::emitGoto(NestableControl* target, GotoKind kind) {
NonLocalExitControl nle(this, kind == GotoKind::Continue
? NonLocalExitKind::Continue
: NonLocalExitKind::Break);
return nle.emitNonLocalJump(target);
}
AbstractScopePtr BytecodeEmitter::innermostScope() const {
return innermostEmitterScope()->scope(this);
}
ScopeIndex BytecodeEmitter::innermostScopeIndex() const {
return *innermostEmitterScope()->scopeIndex(this);
}
bool BytecodeEmitter::emitGCIndexOp(JSOp op, GCThingIndex index) {
MOZ_ASSERT(checkStrictOrSloppy(op));
constexpr size_t OpLength = 1 + GCTHING_INDEX_LEN;
MOZ_ASSERT(GetOpLength(op) == OpLength);
BytecodeOffset offset;
if (!emitCheck(op, OpLength, &offset)) {
return false;
}
jsbytecode* code = bytecodeSection().code(offset);
code[0] = jsbytecode(op);
SET_GCTHING_INDEX(code, index);
bytecodeSection().updateDepth(op, offset);
return true;
}
bool BytecodeEmitter::emitAtomOp(JSOp op, TaggedParserAtomIndex atom) {
MOZ_ASSERT(atom);
// .generator lookups should be emitted as JSOp::GetAliasedVar instead of
// JSOp::GetName etc, to bypass |with| objects on the scope chain.
// It's safe to emit .this lookups though because |with| objects skip
// those.
MOZ_ASSERT_IF(op == JSOp::GetName || op == JSOp::GetGName,
atom != TaggedParserAtomIndex::WellKnown::dot_generator_());
GCThingIndex index;
if (!makeAtomIndex(atom, ParserAtom::Atomize::Yes, &index)) {
return false;
}
return emitAtomOp(op, index);
}
bool BytecodeEmitter::emitAtomOp(JSOp op, GCThingIndex atomIndex) {
MOZ_ASSERT(JOF_OPTYPE(op) == JOF_ATOM);
#ifdef DEBUG
auto atom = perScriptData().gcThingList().getAtom(atomIndex);
MOZ_ASSERT(compilationState.parserAtoms.isInstantiatedAsJSAtom(atom));
#endif
return emitGCIndexOp(op, atomIndex);
}
bool BytecodeEmitter::emitStringOp(JSOp op, TaggedParserAtomIndex atom) {
MOZ_ASSERT(atom);
GCThingIndex index;
if (!makeAtomIndex(atom, ParserAtom::Atomize::No, &index)) {
return false;
}
return emitStringOp(op, index);
}
bool BytecodeEmitter::emitStringOp(JSOp op, GCThingIndex atomIndex) {
MOZ_ASSERT(JOF_OPTYPE(op) == JOF_STRING);
return emitGCIndexOp(op, atomIndex);
}
bool BytecodeEmitter::emitInternedScopeOp(GCThingIndex index, JSOp op) {
MOZ_ASSERT(JOF_OPTYPE(op) == JOF_SCOPE);
MOZ_ASSERT(index < perScriptData().gcThingList().length());
return emitGCIndexOp(op, index);
}
bool BytecodeEmitter::emitInternedObjectOp(GCThingIndex index, JSOp op) {
MOZ_ASSERT(JOF_OPTYPE(op) == JOF_OBJECT);
MOZ_ASSERT(index < perScriptData().gcThingList().length());
return emitGCIndexOp(op, index);
}
bool BytecodeEmitter::emitRegExp(GCThingIndex index) {
return emitGCIndexOp(JSOp::RegExp, index);
}
bool BytecodeEmitter::emitLocalOp(JSOp op, uint32_t slot) {
MOZ_ASSERT(JOF_OPTYPE(op) != JOF_ENVCOORD);
MOZ_ASSERT(IsLocalOp(op));
BytecodeOffset off;
if (!emitN(op, LOCALNO_LEN, &off)) {
return false;
}
SET_LOCALNO(bytecodeSection().code(off), slot);
return true;
}
bool BytecodeEmitter::emitArgOp(JSOp op, uint16_t slot) {
MOZ_ASSERT(IsArgOp(op));
BytecodeOffset off;
if (!emitN(op, ARGNO_LEN, &off)) {
return false;
}
SET_ARGNO(bytecodeSection().code(off), slot);
return true;
}
bool BytecodeEmitter::emitEnvCoordOp(JSOp op, EnvironmentCoordinate ec) {
MOZ_ASSERT(JOF_OPTYPE(op) == JOF_ENVCOORD ||
JOF_OPTYPE(op) == JOF_DEBUGCOORD);
constexpr size_t N = ENVCOORD_HOPS_LEN + ENVCOORD_SLOT_LEN;
MOZ_ASSERT(GetOpLength(op) == 1 + N);
BytecodeOffset off;
if (!emitN(op, N, &off)) {
return false;
}
jsbytecode* pc = bytecodeSection().code(off);
SET_ENVCOORD_HOPS(pc, ec.hops());
pc += ENVCOORD_HOPS_LEN;
SET_ENVCOORD_SLOT(pc, ec.slot());
pc += ENVCOORD_SLOT_LEN;
return true;
}
JSOp BytecodeEmitter::strictifySetNameOp(JSOp op) {
switch (op) {
case JSOp::SetName:
if (sc->strict()) {
op = JSOp::StrictSetName;
}
break;
case JSOp::SetGName:
if (sc->strict()) {
op = JSOp::StrictSetGName;
}
break;
default:;
}
return op;
}
bool BytecodeEmitter::checkSideEffects(ParseNode* pn, bool* answer) {
AutoCheckRecursionLimit recursion(fc);
if (!recursion.check(fc)) {
return false;
}
restart:
switch (pn->getKind()) {
// Trivial cases with no side effects.
case ParseNodeKind::EmptyStmt:
case ParseNodeKind::TrueExpr:
case ParseNodeKind::FalseExpr:
case ParseNodeKind::NullExpr:
case ParseNodeKind::RawUndefinedExpr:
case ParseNodeKind::Elision:
case ParseNodeKind::Generator:
MOZ_ASSERT(pn->is<NullaryNode>());
*answer = false;
return true;
case ParseNodeKind::ObjectPropertyName:
case ParseNodeKind::PrivateName: // no side effects, unlike
// ParseNodeKind::Name
case ParseNodeKind::StringExpr:
case ParseNodeKind::TemplateStringExpr:
MOZ_ASSERT(pn->is<NameNode>());
*answer = false;
return true;
case ParseNodeKind::RegExpExpr:
MOZ_ASSERT(pn->is<RegExpLiteral>());
*answer = false;
return true;
case ParseNodeKind::NumberExpr:
MOZ_ASSERT(pn->is<NumericLiteral>());
*answer = false;
return true;
case ParseNodeKind::BigIntExpr:
MOZ_ASSERT(pn->is<BigIntLiteral>());
*answer = false;
return true;
// |this| can throw in derived class constructors, including nested arrow
// functions or eval.
case ParseNodeKind::ThisExpr:
MOZ_ASSERT(pn->is<UnaryNode>());
*answer = sc->needsThisTDZChecks();
return true;
// |new.target| doesn't have any side-effects.
case ParseNodeKind::NewTargetExpr: {
MOZ_ASSERT(pn->is<NewTargetNode>());
*answer = false;
return true;
}
// Trivial binary nodes with more token pos holders.
case ParseNodeKind::ImportMetaExpr: {
MOZ_ASSERT(pn->as<BinaryNode>().left()->isKind(ParseNodeKind::PosHolder));
MOZ_ASSERT(
pn->as<BinaryNode>().right()->isKind(ParseNodeKind::PosHolder));
*answer = false;
return true;
}
case ParseNodeKind::BreakStmt:
MOZ_ASSERT(pn->is<BreakStatement>());
*answer = true;
return true;
case ParseNodeKind::ContinueStmt:
MOZ_ASSERT(pn->is<ContinueStatement>());
*answer = true;
return true;
case ParseNodeKind::DebuggerStmt:
MOZ_ASSERT(pn->is<DebuggerStatement>());
*answer = true;
return true;
// Watch out for getters!
case ParseNodeKind::OptionalDotExpr:
case ParseNodeKind::DotExpr:
case ParseNodeKind::ArgumentsLength:
MOZ_ASSERT(pn->is<BinaryNode>());
*answer = true;
return true;
// Unary cases with side effects only if the child has them.
case ParseNodeKind::TypeOfExpr:
case ParseNodeKind::VoidExpr:
case ParseNodeKind::NotExpr:
return checkSideEffects(pn->as<UnaryNode>().kid(), answer);
// Even if the name expression is effect-free, performing ToPropertyKey on
// it might not be effect-free:
//
// RegExp.prototype.toString = () => { throw 42; };
// ({ [/regex/]: 0 }); // ToPropertyKey(/regex/) throws 42
//
// function Q() {
// ({ [new.target]: 0 });
// }
// Q.toString = () => { throw 17; };
// new Q; // new.target will be Q, ToPropertyKey(Q) throws 17
case ParseNodeKind::ComputedName:
MOZ_ASSERT(pn->is<UnaryNode>());
*answer = true;
return true;
// Looking up or evaluating the associated name could throw.
case ParseNodeKind::TypeOfNameExpr:
MOZ_ASSERT(pn->is<UnaryNode>());
*answer = true;
return true;
// This unary case has side effects on the enclosing object, sure. But
// that's not the question this function answers: it's whether the
// operation may have a side effect on something *other* than the result
// of the overall operation in which it's embedded. The answer to that
// is no, because an object literal having a mutated prototype only
// produces a value, without affecting anything else.
case ParseNodeKind::MutateProto:
return checkSideEffects(pn->as<UnaryNode>().kid(), answer);
// Unary cases with obvious side effects.
case ParseNodeKind::PreIncrementExpr:
case ParseNodeKind::PostIncrementExpr:
case ParseNodeKind::PreDecrementExpr:
case ParseNodeKind::PostDecrementExpr:
case ParseNodeKind::ThrowStmt:
MOZ_ASSERT(pn->is<UnaryNode>());
*answer = true;
return true;
// These might invoke valueOf/toString, even with a subexpression without
// side effects! Consider |+{ valueOf: null, toString: null }|.
case ParseNodeKind::BitNotExpr:
case ParseNodeKind::PosExpr:
case ParseNodeKind::NegExpr:
MOZ_ASSERT(pn->is<UnaryNode>());
*answer = true;
return true;
// This invokes the (user-controllable) iterator protocol.
case ParseNodeKind::Spread:
MOZ_ASSERT(pn->is<UnaryNode>());
*answer = true;
return true;
case ParseNodeKind::InitialYield:
case ParseNodeKind::YieldStarExpr:
case ParseNodeKind::YieldExpr:
case ParseNodeKind::AwaitExpr:
MOZ_ASSERT(pn->is<UnaryNode>());
*answer = true;
return true;
// Deletion generally has side effects, even if isolated cases have none.
case ParseNodeKind::DeleteNameExpr:
case ParseNodeKind::DeletePropExpr:
case ParseNodeKind::DeleteElemExpr:
case ParseNodeKind::DeleteOptionalChainExpr:
MOZ_ASSERT(pn->is<UnaryNode>());
*answer = true;
return true;
// Deletion of a non-Reference expression has side effects only through
// evaluating the expression.
case ParseNodeKind::DeleteExpr: {
ParseNode* expr = pn->as<UnaryNode>().kid();
return checkSideEffects(expr, answer);
}
case ParseNodeKind::ExpressionStmt:
return checkSideEffects(pn->as<UnaryNode>().kid(), answer);
// Binary cases with obvious side effects.
case ParseNodeKind::InitExpr:
*answer = true;
return true;
case ParseNodeKind::AssignExpr:
case ParseNodeKind::AddAssignExpr:
case ParseNodeKind::SubAssignExpr:
case ParseNodeKind::CoalesceAssignExpr:
case ParseNodeKind::OrAssignExpr:
case ParseNodeKind::AndAssignExpr:
case ParseNodeKind::BitOrAssignExpr:
case ParseNodeKind::BitXorAssignExpr:
case ParseNodeKind::BitAndAssignExpr:
case ParseNodeKind::LshAssignExpr:
case ParseNodeKind::RshAssignExpr:
case ParseNodeKind::UrshAssignExpr:
case ParseNodeKind::MulAssignExpr:
case ParseNodeKind::DivAssignExpr:
case ParseNodeKind::ModAssignExpr:
case ParseNodeKind::PowAssignExpr:
MOZ_ASSERT(pn->is<AssignmentNode>());
*answer = true;
return true;
case ParseNodeKind::SetThis:
MOZ_ASSERT(pn->is<BinaryNode>());
*answer = true;
return true;
case ParseNodeKind::StatementList:
// Strict equality operations and short circuit operators are well-behaved
// and perform no conversions.
case ParseNodeKind::CoalesceExpr:
case ParseNodeKind::OrExpr:
case ParseNodeKind::AndExpr:
case ParseNodeKind::StrictEqExpr:
case ParseNodeKind::StrictNeExpr:
// Any subexpression of a comma expression could be effectful.
case ParseNodeKind::CommaExpr:
MOZ_ASSERT(!pn->as<ListNode>().empty());
[[fallthrough]];
// Subcomponents of a literal may be effectful.
case ParseNodeKind::ArrayExpr:
case ParseNodeKind::ObjectExpr:
for (ParseNode* item : pn->as<ListNode>().contents()) {
if (!checkSideEffects(item, answer)) {
return false;
}
if (*answer) {
return true;
}
}
return true;
#ifdef ENABLE_RECORD_TUPLE
case ParseNodeKind::RecordExpr:
case ParseNodeKind::TupleExpr:
MOZ_CRASH("Record and Tuple are not supported yet");
#endif
#ifdef ENABLE_DECORATORS
case ParseNodeKind::DecoratorList:
MOZ_CRASH("Decorators are not supported yet");
#endif
// Most other binary operations (parsed as lists in SpiderMonkey) may
// perform conversions triggering side effects. Math operations perform
// ToNumber and may fail invoking invalid user-defined toString/valueOf:
// |5 < { toString: null }|. |instanceof| throws if provided a
// non-object constructor: |null instanceof null|. |in| throws if given
// a non-object RHS: |5 in null|.
case ParseNodeKind::BitOrExpr:
case ParseNodeKind::BitXorExpr:
case ParseNodeKind::BitAndExpr:
case ParseNodeKind::EqExpr:
case ParseNodeKind::NeExpr:
case ParseNodeKind::LtExpr:
case ParseNodeKind::LeExpr:
case ParseNodeKind::GtExpr:
case ParseNodeKind::GeExpr:
case ParseNodeKind::InstanceOfExpr:
case ParseNodeKind::InExpr:
case ParseNodeKind::PrivateInExpr:
case ParseNodeKind::LshExpr:
case ParseNodeKind::RshExpr:
case ParseNodeKind::UrshExpr:
case ParseNodeKind::AddExpr:
case ParseNodeKind::SubExpr:
case ParseNodeKind::MulExpr:
case ParseNodeKind::DivExpr:
case ParseNodeKind::ModExpr:
case ParseNodeKind::PowExpr:
MOZ_ASSERT(pn->as<ListNode>().count() >= 2);
*answer = true;
return true;
case ParseNodeKind::PropertyDefinition:
case ParseNodeKind::Case: {
BinaryNode* node = &pn->as<BinaryNode>();
if (!checkSideEffects(node->left(), answer)) {
return false;
}
if (*answer) {
return true;
}
return checkSideEffects(node->right(), answer);
}
// More getters.
case ParseNodeKind::ElemExpr:
case ParseNodeKind::OptionalElemExpr:
MOZ_ASSERT(pn->is<BinaryNode>());
*answer = true;
return true;
// Throws if the operand is not of the right class. Can also call a private
// getter.
case ParseNodeKind::PrivateMemberExpr:
case ParseNodeKind::OptionalPrivateMemberExpr:
*answer = true;
return true;
// These affect visible names in this code, or in other code.
case ParseNodeKind::ImportDecl:
case ParseNodeKind::ExportFromStmt:
case ParseNodeKind::ExportDefaultStmt:
MOZ_ASSERT(pn->is<BinaryNode>());
*answer = true;
return true;
// Likewise.
case ParseNodeKind::ExportStmt:
MOZ_ASSERT(pn->is<UnaryNode>());
*answer = true;
return true;
case ParseNodeKind::CallImportExpr:
case ParseNodeKind::CallImportSpec:
MOZ_ASSERT(pn->is<BinaryNode>());
*answer = true;
return true;
// Every part of a loop might be effect-free, but looping infinitely *is*
// an effect. (Language lawyer trivia: C++ says threads can be assumed
// to exit or have side effects, C++14 [intro.multithread]p27, so a C++
// implementation's equivalent of the below could set |*answer = false;|
// if all loop sub-nodes set |*answer = false|!)
case ParseNodeKind::DoWhileStmt:
case ParseNodeKind::WhileStmt:
case ParseNodeKind::ForStmt:
MOZ_ASSERT(pn->is<BinaryNode>());
*answer = true;
return true;
// Declarations affect the name set of the relevant scope.
case ParseNodeKind::VarStmt:
case ParseNodeKind::ConstDecl:
case ParseNodeKind::LetDecl:
MOZ_ASSERT(pn->is<ListNode>());
*answer = true;
return true;
case ParseNodeKind::IfStmt:
case ParseNodeKind::ConditionalExpr: {
TernaryNode* node = &pn->as<TernaryNode>();
if (!checkSideEffects(node->kid1(), answer)) {
return false;
}
if (*answer) {
return true;
}
if (!checkSideEffects(node->kid2(), answer)) {
return false;
}
if (*answer) {
return true;
}
if ((pn = node->kid3())) {
goto restart;
}
return true;
}
// Function calls can invoke non-local code.
case ParseNodeKind::NewExpr:
case ParseNodeKind::CallExpr:
case ParseNodeKind::OptionalCallExpr:
case ParseNodeKind::TaggedTemplateExpr:
case ParseNodeKind::SuperCallExpr:
MOZ_ASSERT(pn->is<BinaryNode>());
*answer = true;
return true;
// Function arg lists can contain arbitrary expressions. Technically
// this only causes side-effects if one of the arguments does, but since
// the call being made will always trigger side-effects, it isn't needed.
case ParseNodeKind::Arguments:
MOZ_ASSERT(pn->is<ListNode>());
*answer = true;
return true;
case ParseNodeKind::OptionalChain:
MOZ_ASSERT(pn->is<UnaryNode>());
*answer = true;
return true;
// Classes typically introduce names. Even if no name is introduced,
// the heritage and/or class body (through computed property names)
// usually have effects.
case ParseNodeKind::ClassDecl:
MOZ_ASSERT(pn->is<ClassNode>());
*answer = true;
return true;
// |with| calls |ToObject| on its expression and so throws if that value
// is null/undefined.
case ParseNodeKind::WithStmt:
MOZ_ASSERT(pn->is<BinaryNode>());
*answer = true;
return true;
case ParseNodeKind::ReturnStmt:
MOZ_ASSERT(pn->is<BinaryNode>());
*answer = true;
return true;
case ParseNodeKind::Name:
MOZ_ASSERT(pn->is<NameNode>());
*answer = true;
return true;
// Shorthands could trigger getters: the |x| in the object literal in
// |with ({ get x() { throw 42; } }) ({ x });|, for example, triggers
// one. (Of course, it isn't necessary to use |with| for a shorthand to
// trigger a getter.)
case ParseNodeKind::Shorthand:
MOZ_ASSERT(pn->is<BinaryNode>());
*answer = true;
return true;
case ParseNodeKind::Function:
MOZ_ASSERT(pn->is<FunctionNode>());
/*
* A named function, contrary to ES3, is no longer effectful, because
* we bind its name lexically (using JSOp::Callee) instead of creating
* an Object instance and binding a readonly, permanent property in it
* (the object and binding can be detected and hijacked or captured).
* This is a bug fix to ES3; it is fixed in ES3.1 drafts.
*/
*answer = false;
return true;
case ParseNodeKind::Module:
*answer = false;
return true;
case ParseNodeKind::TryStmt: {
TryNode* tryNode = &pn->as<TryNode>();
if (!checkSideEffects(tryNode->body(), answer)) {
return false;
}
if (*answer) {
return true;
}
if (LexicalScopeNode* catchScope = tryNode->catchScope()) {
if (!checkSideEffects(catchScope, answer)) {
return false;
}
if (*answer) {
return true;
}
}
if (ParseNode* finallyBlock = tryNode->finallyBlock()) {
if (!checkSideEffects(finallyBlock, answer)) {
return false;
}
}
return true;
}
case ParseNodeKind::Catch: {
BinaryNode* catchClause = &pn->as<BinaryNode>();
if (ParseNode* name = catchClause->left()) {
if (!checkSideEffects(name, answer)) {
return false;
}
if (*answer) {
return true;
}
}
return checkSideEffects(catchClause->right(), answer);
}
case ParseNodeKind::SwitchStmt: {
SwitchStatement* switchStmt = &pn->as<SwitchStatement>();
if (!checkSideEffects(&switchStmt->discriminant(), answer)) {
return false;
}
return *answer ||
checkSideEffects(&switchStmt->lexicalForCaseList(), answer);
}
case ParseNodeKind::LabelStmt:
return checkSideEffects(pn->as<LabeledStatement>().statement(), answer);
case ParseNodeKind::LexicalScope:
return checkSideEffects(pn->as<LexicalScopeNode>().scopeBody(), answer);
// We could methodically check every interpolated expression, but it's
// probably not worth the trouble. Treat template strings as effect-free
// only if they don't contain any substitutions.
case ParseNodeKind::TemplateStringListExpr: {
ListNode* list = &pn->as<ListNode>();
MOZ_ASSERT(!list->empty());
MOZ_ASSERT((list->count() % 2) == 1,
"template strings must alternate template and substitution "
"parts");
*answer = list->count() > 1;
return true;
}
// This should be unreachable but is left as-is for now.
case ParseNodeKind::ParamsBody:
*answer = true;
return true;
case ParseNodeKind::ForIn: // by ParseNodeKind::For
case ParseNodeKind::ForOf: // by ParseNodeKind::For
case ParseNodeKind::ForHead: // by ParseNodeKind::For
case ParseNodeKind::DefaultConstructor: // by ParseNodeKind::ClassDecl
case ParseNodeKind::ClassBodyScope: // by ParseNodeKind::ClassDecl
case ParseNodeKind::ClassMethod: // by ParseNodeKind::ClassDecl
case ParseNodeKind::ClassField: // by ParseNodeKind::ClassDecl
case ParseNodeKind::ClassNames: // by ParseNodeKind::ClassDecl
case ParseNodeKind::StaticClassBlock: // by ParseNodeKind::ClassDecl
case ParseNodeKind::ClassMemberList: // by ParseNodeKind::ClassDecl
case ParseNodeKind::ImportSpecList: // by ParseNodeKind::Import
case ParseNodeKind::ImportSpec: // by ParseNodeKind::Import
case ParseNodeKind::ImportNamespaceSpec: // by ParseNodeKind::Import
case ParseNodeKind::ImportAttribute: // by ParseNodeKind::Import
case ParseNodeKind::ImportAttributeList: // by ParseNodeKind::Import
case ParseNodeKind::ImportModuleRequest: // by ParseNodeKind::Import
case ParseNodeKind::ExportBatchSpecStmt: // by ParseNodeKind::Export
case ParseNodeKind::ExportSpecList: // by ParseNodeKind::Export
case ParseNodeKind::ExportSpec: // by ParseNodeKind::Export
case ParseNodeKind::ExportNamespaceSpec: // by ParseNodeKind::Export
case ParseNodeKind::CallSiteObj: // by ParseNodeKind::TaggedTemplate
case ParseNodeKind::PosHolder: // by ParseNodeKind::NewTarget
case ParseNodeKind::SuperBase: // by ParseNodeKind::Elem and others
case ParseNodeKind::PropertyNameExpr: // by ParseNodeKind::Dot
MOZ_CRASH("handled by parent nodes");
case ParseNodeKind::LastUnused:
case ParseNodeKind::Limit:
MOZ_CRASH("invalid node kind");
}
MOZ_CRASH(
"invalid, unenumerated ParseNodeKind value encountered in "
"BytecodeEmitter::checkSideEffects");
}
bool BytecodeEmitter::isInLoop() {
return findInnermostNestableControl<LoopControl>();
}
bool BytecodeEmitter::checkSingletonContext() {
MOZ_ASSERT_IF(sc->treatAsRunOnce(), sc->isTopLevelContext());
return sc->treatAsRunOnce() && !isInLoop();
}
bool BytecodeEmitter::needsImplicitThis() {
// Short-circuit if there is an enclosing 'with' scope.
if (sc->inWith()) {
return true;
}
// Otherwise see if the current point is under a 'with'.
for (EmitterScope* es = innermostEmitterScope(); es;
es = es->enclosingInFrame()) {
if (es->scope(this).kind() == ScopeKind::With) {
return true;
}
}
return false;
}
size_t BytecodeEmitter::countThisEnvironmentHops() {
unsigned numHops = 0;
for (BytecodeEmitter* current = this; current; current = current->parent) {
for (EmitterScope* es = current->innermostEmitterScope(); es;
es = es->enclosingInFrame()) {
if (es->scope(current).is<FunctionScope>()) {
if (!es->scope(current).isArrow()) {
// The Parser is responsible for marking the environment as either
// closed-over or used-by-eval which ensure that is must exist.
MOZ_ASSERT(es->scope(current).hasEnvironment());
return numHops;
}
}
if (es->scope(current).hasEnvironment()) {
numHops++;
}
}
}
// The "this" environment exists outside of the compilation, but the
// `ScopeContext` recorded the number of additional hops needed, so add
// those in now.
MOZ_ASSERT(sc->allowSuperProperty());
numHops += compilationState.scopeContext.enclosingThisEnvironmentHops;
return numHops;
}
bool BytecodeEmitter::emitThisEnvironmentCallee() {
// Get the innermost enclosing function that has a |this| binding.
// Directly load callee from the frame if possible.
if (sc->isFunctionBox() && !sc->asFunctionBox()->isArrow()) {
return emit1(JSOp::Callee);
}
// We have to load the callee from the environment chain.
size_t numHops = countThisEnvironmentHops();
static_assert(
ENVCOORD_HOPS_LIMIT - 1 <= UINT8_MAX,
"JSOp::EnvCallee operand size should match ENVCOORD_HOPS_LIMIT");
MOZ_ASSERT(numHops < ENVCOORD_HOPS_LIMIT - 1);
return emit2(JSOp::EnvCallee, numHops);
}
bool BytecodeEmitter::emitSuperBase() {
if (!emitThisEnvironmentCallee()) {
return false;
}
return emit1(JSOp::SuperBase);
}
void BytecodeEmitter::reportError(ParseNode* pn, unsigned errorNumber, ...) {
uint32_t offset = pn ? pn->pn_pos.begin : *scriptStartOffset;
va_list args;
va_start(args, errorNumber);
errorReporter().errorWithNotesAtVA(nullptr, AsVariant(offset), errorNumber,
&args);
va_end(args);
}
void BytecodeEmitter::reportError(uint32_t offset, unsigned errorNumber, ...) {
va_list args;
va_start(args, errorNumber);
errorReporter().errorWithNotesAtVA(nullptr, AsVariant(offset), errorNumber,
&args);
va_end(args);
}
bool BytecodeEmitter::addObjLiteralData(ObjLiteralWriter& writer,
GCThingIndex* outIndex) {
if (!writer.checkForDuplicatedNames(fc)) {
return false;
}
size_t len = writer.getCode().size();
auto* code = compilationState.alloc.newArrayUninitialized<uint8_t>(len);
if (!code) {
js::ReportOutOfMemory(fc);
return false;
}
memcpy(code, writer.getCode().data(), len);
ObjLiteralIndex objIndex(compilationState.objLiteralData.length());
if (uint32_t(objIndex) >= TaggedScriptThingIndex::IndexLimit) {
ReportAllocationOverflow(fc);
return false;
}
if (!compilationState.objLiteralData.emplaceBack(code, len, writer.getKind(),
writer.getFlags(),
writer.getPropertyCount())) {
js::ReportOutOfMemory(fc);
return false;
}
return perScriptData().gcThingList().append(objIndex, outIndex);
}
bool BytecodeEmitter::emitPrepareIteratorResult() {
constexpr JSOp op = JSOp::NewObject;
ObjLiteralWriter writer;
writer.beginShape(op);
writer.setPropNameNoDuplicateCheck(parserAtoms(),
TaggedParserAtomIndex::WellKnown::value());
if (!writer.propWithUndefinedValue(fc)) {
return false;
}
writer.setPropNameNoDuplicateCheck(parserAtoms(),
TaggedParserAtomIndex::WellKnown::done());
if (!writer.propWithUndefinedValue(fc)) {
return false;
}
GCThingIndex shape;
if (!addObjLiteralData(writer, &shape)) {
return false;
}
return emitGCIndexOp(op, shape);
}
bool BytecodeEmitter::emitFinishIteratorResult(bool done) {
if (!emitAtomOp(JSOp::InitProp, TaggedParserAtomIndex::WellKnown::value())) {
return false;
}
if (!emit1(done ? JSOp::True : JSOp::False)) {
return false;
}
if (!emitAtomOp(JSOp::InitProp, TaggedParserAtomIndex::WellKnown::done())) {
return false;
}
return true;
}
bool BytecodeEmitter::emitGetNameAtLocation(TaggedParserAtomIndex name,
const NameLocation& loc) {
NameOpEmitter noe(this, name, loc, NameOpEmitter::Kind::Get);
if (!noe.emitGet()) {
return false;
}
return true;
}
bool BytecodeEmitter::emitGetName(NameNode* name) {
MOZ_ASSERT(name->isKind(ParseNodeKind::Name));
return emitGetName(name->name());
}
bool BytecodeEmitter::emitGetPrivateName(NameNode* name) {
MOZ_ASSERT(name->isKind(ParseNodeKind::PrivateName));
return emitGetPrivateName(name->name());
}
bool BytecodeEmitter::emitGetPrivateName(TaggedParserAtomIndex nameAtom) {
// The parser ensures the private name is present on the environment chain,
// but its location can be Dynamic or Global when emitting debugger
// eval-in-frame code.
NameLocation location = lookupName(nameAtom);
MOZ_ASSERT(location.kind() == NameLocation::Kind::FrameSlot ||
location.kind() == NameLocation::Kind::EnvironmentCoordinate ||
location.kind() == NameLocation::Kind::Dynamic ||
location.kind() == NameLocation::Kind::Global);
return emitGetNameAtLocation(nameAtom, location);
}
bool BytecodeEmitter::emitTDZCheckIfNeeded(TaggedParserAtomIndex name,
const NameLocation& loc,
ValueIsOnStack isOnStack) {
// Dynamic accesses have TDZ checks built into their VM code and should
// never emit explicit TDZ checks.
MOZ_ASSERT(loc.hasKnownSlot());
MOZ_ASSERT(loc.isLexical() || loc.isPrivateMethod() || loc.isSynthetic());
// Private names are implemented as lexical bindings, but it's just an
// implementation detail. Per spec there's no TDZ check when using them.
if (parserAtoms().isPrivateName(name)) {
return true;
}
Maybe<MaybeCheckTDZ> check =
innermostTDZCheckCache->needsTDZCheck(this, name);
if (!check) {
return false;
}
// We've already emitted a check in this basic block.
if (*check == DontCheckTDZ) {
return true;
}
// If the value is not on the stack, we have to load it first.
if (isOnStack == ValueIsOnStack::No) {
if (loc.kind() == NameLocation::Kind::FrameSlot) {
if (!emitLocalOp(JSOp::GetLocal, loc.frameSlot())) {
return false;
}
} else {
if (!emitEnvCoordOp(JSOp::GetAliasedVar, loc.environmentCoordinate())) {
return false;
}
}
}
// Emit the lexical check.
if (loc.kind() == NameLocation::Kind::FrameSlot) {
if (!emitLocalOp(JSOp::CheckLexical, loc.frameSlot())) {
return false;
}
} else {
if (!emitEnvCoordOp(JSOp::CheckAliasedLexical,
loc.environmentCoordinate())) {
return false;
}
}
// Pop the value if needed.
if (isOnStack == ValueIsOnStack::No) {
if (!emit1(JSOp::Pop)) {
return false;
}
}
return innermostTDZCheckCache->noteTDZCheck(this, name, DontCheckTDZ);
}
bool BytecodeEmitter::emitPropLHS(PropertyAccess* prop) {
MOZ_ASSERT(!prop->isSuper());
ParseNode* expr = &prop->expression();
if (!expr->is<PropertyAccess>() || expr->as<PropertyAccess>().isSuper()) {
// The non-optimized case.
return emitTree(expr);
}
// If the object operand is also a dotted property reference, reverse the
// list linked via expression() temporarily so we can iterate over it from
// the bottom up (reversing again as we go), to avoid excessive recursion.
PropertyAccess* pndot = &expr->as<PropertyAccess>();
ParseNode* pnup = nullptr;
ParseNode* pndown;
for (;;) {
// Reverse pndot->expression() to point up, not down.
pndown = &pndot->expression();
pndot->setExpression(pnup);
if (!pndown->is<PropertyAccess>() ||
pndown->as<PropertyAccess>().isSuper()) {
break;
}
pnup = pndot;
pndot = &pndown->as<PropertyAccess>();
}
// pndown is a primary expression, not a dotted property reference.
if (!emitTree(pndown)) {
return false;
}
while (true) {
// Walk back up the list, emitting annotated name ops.
if (!emitAtomOp(JSOp::GetProp, pndot->key().atom())) {
return false;
}
// Reverse the pndot->expression() link again.
pnup = pndot->maybeExpression();
pndot->setExpression(pndown);
pndown = pndot;
if (!pnup) {
break;
}
pndot = &pnup->as<PropertyAccess>();
}
return true;
}
bool BytecodeEmitter::emitPropIncDec(UnaryNode* incDec, ValueUsage valueUsage) {
PropertyAccess* prop = &incDec->kid()->as<PropertyAccess>();
bool isSuper = prop->isSuper();
ParseNodeKind kind = incDec->getKind();
PropOpEmitter poe(
this,
kind == ParseNodeKind::PostIncrementExpr
? PropOpEmitter::Kind::PostIncrement
: kind == ParseNodeKind::PreIncrementExpr
? PropOpEmitter::Kind::PreIncrement
: kind == ParseNodeKind::PostDecrementExpr
? PropOpEmitter::Kind::PostDecrement
: PropOpEmitter::Kind::PreDecrement,
isSuper ? PropOpEmitter::ObjKind::Super : PropOpEmitter::ObjKind::Other);
if (!poe.prepareForObj()) {
return false;
}
if (isSuper) {
UnaryNode* base = &prop->expression().as<UnaryNode>();
if (!emitGetThisForSuperBase(base)) {
// [stack] THIS
return false;
}
} else {
if (!emitPropLHS(prop)) {
// [stack] OBJ
return false;
}
}
if (!poe.emitIncDec(prop->key().atom(), valueUsage)) {
// [stack] RESULT
return false;
}
return true;
}
bool BytecodeEmitter::emitNameIncDec(UnaryNode* incDec, ValueUsage valueUsage) {
MOZ_ASSERT(incDec->kid()->isKind(ParseNodeKind::Name));
ParseNodeKind kind = incDec->getKind();
NameNode* name = &incDec->kid()->as<NameNode>();
NameOpEmitter noe(this, name->atom(),
kind == ParseNodeKind::PostIncrementExpr
? NameOpEmitter::Kind::PostIncrement
: kind == ParseNodeKind::PreIncrementExpr
? NameOpEmitter::Kind::PreIncrement
: kind == ParseNodeKind::PostDecrementExpr
? NameOpEmitter::Kind::PostDecrement
: NameOpEmitter::Kind::PreDecrement);
if (!noe.emitIncDec(valueUsage)) {
return false;
}
return true;
}
bool BytecodeEmitter::emitObjAndKey(ParseNode* exprOrSuper, ParseNode* key,
ElemOpEmitter& eoe) {
if (exprOrSuper->isKind(ParseNodeKind::SuperBase)) {
if (!eoe.prepareForObj()) {
// [stack]
return false;
}
UnaryNode* base = &exprOrSuper->as<UnaryNode>();
if (!emitGetThisForSuperBase(base)) {
// [stack] THIS
return false;
}
if (!eoe.prepareForKey()) {
// [stack] THIS
return false;
}
if (!emitTree(key)) {
// [stack] THIS KEY
return false;
}
return true;
}
if (!eoe.prepareForObj()) {
// [stack]
return false;
}
if (!emitTree(exprOrSuper)) {
// [stack] OBJ
return false;
}
if (!eoe.prepareForKey()) {
// [stack] OBJ? OBJ
return false;
}
if (!emitTree(key)) {
// [stack] OBJ? OBJ KEY
return false;
}
return true;
}
bool BytecodeEmitter::emitElemOpBase(JSOp op) {
if (!emit1(op)) {
return false;
}
return true;
}
bool BytecodeEmitter::emitElemObjAndKey(PropertyByValue* elem, bool isSuper,
ElemOpEmitter& eoe) {
MOZ_ASSERT(isSuper == elem->expression().isKind(ParseNodeKind::SuperBase));
return emitObjAndKey(&elem->expression(), &elem->key(), eoe);
}
static ElemOpEmitter::Kind ConvertIncDecKind(ParseNodeKind kind) {
switch (kind) {
case ParseNodeKind::PostIncrementExpr:
return ElemOpEmitter::Kind::PostIncrement;
case ParseNodeKind::PreIncrementExpr:
return ElemOpEmitter::Kind::PreIncrement;
case ParseNodeKind::PostDecrementExpr:
return ElemOpEmitter::Kind::PostDecrement;
case ParseNodeKind::PreDecrementExpr:
return ElemOpEmitter::Kind::PreDecrement;
default:
MOZ_CRASH("unexpected inc/dec node kind");
}
}
static PrivateOpEmitter::Kind PrivateConvertIncDecKind(ParseNodeKind kind) {
switch (kind) {
case ParseNodeKind::PostIncrementExpr:
return PrivateOpEmitter::Kind::PostIncrement;
case ParseNodeKind::PreIncrementExpr:
return PrivateOpEmitter::Kind::PreIncrement;
case ParseNodeKind::PostDecrementExpr:
return PrivateOpEmitter::Kind::PostDecrement;
case ParseNodeKind::PreDecrementExpr:
return PrivateOpEmitter::Kind::PreDecrement;
default:
MOZ_CRASH("unexpected inc/dec node kind");
}
}
bool BytecodeEmitter::emitElemIncDec(UnaryNode* incDec, ValueUsage valueUsage) {
PropertyByValue* elemExpr = &incDec->kid()->as<PropertyByValue>();
bool isSuper = elemExpr->isSuper();
MOZ_ASSERT(!elemExpr->key().isKind(ParseNodeKind::PrivateName));
ParseNodeKind kind = incDec->getKind();
ElemOpEmitter eoe(
this, ConvertIncDecKind(kind),
isSuper ? ElemOpEmitter::ObjKind::Super : ElemOpEmitter::ObjKind::Other);
if (!emitElemObjAndKey(elemExpr, isSuper, eoe)) {
// [stack] # if Super
// [stack] THIS KEY
// [stack] # otherwise
// [stack] OBJ KEY
return false;
}
if (!eoe.emitIncDec(valueUsage)) {
// [stack] RESULT
return false;
}
return true;
}
bool BytecodeEmitter::emitCallIncDec(UnaryNode* incDec) {
MOZ_ASSERT(incDec->isKind(ParseNodeKind::PreIncrementExpr) ||
incDec->isKind(ParseNodeKind::PostIncrementExpr) ||
incDec->isKind(ParseNodeKind::PreDecrementExpr) ||
incDec->isKind(ParseNodeKind::PostDecrementExpr));
ParseNode* call = incDec->kid();
MOZ_ASSERT(call->isKind(ParseNodeKind::CallExpr));
if (!emitTree(call)) {
// [stack] CALLRESULT
return false;
}
if (!emit1(JSOp::ToNumeric)) {
// [stack] N
return false;
}
// The increment/decrement has no side effects, so proceed to throw for
// invalid assignment target.
return emit2(JSOp::ThrowMsg, uint8_t(ThrowMsgKind::AssignToCall));
}
bool BytecodeEmitter::emitPrivateIncDec(UnaryNode* incDec,
ValueUsage valueUsage) {
PrivateMemberAccess* privateExpr = &incDec->kid()->as<PrivateMemberAccess>();
ParseNodeKind kind = incDec->getKind();
PrivateOpEmitter xoe(this, PrivateConvertIncDecKind(kind),
privateExpr->privateName().name());
if (!emitTree(&privateExpr->expression())) {
// [stack] OBJ
return false;
}
if (!xoe.emitReference()) {
// [stack] OBJ NAME
return false;
}
if (!xoe.emitIncDec(valueUsage)) {
// [stack] RESULT
return false;
}
return true;
}
bool BytecodeEmitter::emitDouble(double d) {
BytecodeOffset offset;
if (!emitCheck(JSOp::Double, 9, &offset)) {
return false;
}
jsbytecode* code = bytecodeSection().code(offset);
code[0] = jsbytecode(JSOp::Double);
SET_INLINE_VALUE(code, DoubleValue(d));
bytecodeSection().updateDepth(JSOp::Double, offset);
return true;
}
bool BytecodeEmitter::emitNumberOp(double dval) {
int32_t ival;
if (NumberIsInt32(dval, &ival)) {
if (ival == 0) {
return emit1(JSOp::Zero);
}
if (ival == 1) {
return emit1(JSOp::One);
}
if ((int)(int8_t)ival == ival) {
return emit2(JSOp::Int8, uint8_t(int8_t(ival)));
}
uint32_t u = uint32_t(ival);
if (u < Bit(16)) {
if (!emitUint16Operand(JSOp::Uint16, u)) {
return false;
}
} else if (u < Bit(24)) {
BytecodeOffset off;
if (!emitN(JSOp::Uint24, 3, &off)) {
return false;
}
SET_UINT24(bytecodeSection().code(off), u);
} else {
BytecodeOffset off;
if (!emitN(JSOp::Int32, 4, &off)) {
return false;
}
SET_INT32(bytecodeSection().code(off), ival);
}
return true;
}
return emitDouble(dval);
}
/*
* Using MOZ_NEVER_INLINE in here is a workaround for llvm.org/pr14047.
* LLVM is deciding to inline this function which uses a lot of stack space
* into emitTree which is recursive and uses relatively little stack space.
*/
MOZ_NEVER_INLINE bool BytecodeEmitter::emitSwitch(SwitchStatement* switchStmt) {
LexicalScopeNode& lexical = switchStmt->lexicalForCaseList();
MOZ_ASSERT(lexical.isKind(ParseNodeKind::LexicalScope));
ListNode* cases = &lexical.scopeBody()->as<ListNode>();
MOZ_ASSERT(cases->isKind(ParseNodeKind::StatementList));
SwitchEmitter se(this);
if (!se.emitDiscriminant(switchStmt->discriminant().pn_pos.begin)) {
return false;
}
if (!markStepBreakpoint()) {
return false;
}
if (!emitTree(&switchStmt->discriminant())) {
return false;
}
// Enter the scope before pushing the switch BreakableControl since all
// breaks are under this scope.
if (!lexical.isEmptyScope()) {
if (!se.emitLexical(lexical.scopeBindings())) {
return false;
}
// A switch statement may contain hoisted functions inside its
// cases. The hasTopLevelFunctionDeclarations flag is propagated from the
// StatementList bodies of the cases to the case list.
if (cases->hasTopLevelFunctionDeclarations()) {
for (ParseNode* item : cases->contents()) {
CaseClause* caseClause = &item->as<CaseClause>();
ListNode* statements = caseClause->statementList();
if (statements->hasTopLevelFunctionDeclarations()) {
if (!emitHoistedFunctionsInList(statements)) {
return false;
}
}
}
}
} else {
MOZ_ASSERT(!cases->hasTopLevelFunctionDeclarations());
}
SwitchEmitter::TableGenerator tableGen(this);
uint32_t caseCount = cases->count() - (switchStmt->hasDefault() ? 1 : 0);
if (caseCount == 0) {
tableGen.finish(0);
} else {
for (ParseNode* item : cases->contents()) {
CaseClause* caseClause = &item->as<CaseClause>();
if (caseClause->isDefault()) {
continue;
}
ParseNode* caseValue = caseClause->caseExpression();
if (caseValue->getKind() != ParseNodeKind::NumberExpr) {
tableGen.setInvalid();
break;
}
int32_t i;
if (!NumberEqualsInt32(caseValue->as<NumericLiteral>().value(), &i)) {
tableGen.setInvalid();
break;
}
if (!tableGen.addNumber(i)) {
return false;
}
}
tableGen.finish(caseCount);
}
if (!se.validateCaseCount(caseCount)) {
return false;
}
bool isTableSwitch = tableGen.isValid();
if (isTableSwitch) {
if (!se.emitTable(tableGen)) {
return false;
}
} else {
if (!se.emitCond()) {
return false;
}
// Emit code for evaluating cases and jumping to case statements.
for (ParseNode* item : cases->contents()) {
CaseClause* caseClause = &item->as<CaseClause>();
if (caseClause->isDefault()) {
continue;
}
if (!se.prepareForCaseValue()) {
return false;
}
ParseNode* caseValue = caseClause->caseExpression();
// If the expression is a literal, suppress line number emission so
// that debugging works more naturally.
if (!emitTree(
caseValue, ValueUsage::WantValue,
caseValue->isLiteral() ? SUPPRESS_LINENOTE : EMIT_LINENOTE)) {
return false;
}
if (!se.emitCaseJump()) {
return false;
}
}
}
// Emit code for each case's statements.
for (ParseNode* item : cases->contents()) {
CaseClause* caseClause = &item->as<CaseClause>();
if (caseClause->isDefault()) {
if (!se.emitDefaultBody()) {
return false;
}
} else {
if (isTableSwitch) {
ParseNode* caseValue = caseClause->caseExpression();
MOZ_ASSERT(caseValue->isKind(ParseNodeKind::NumberExpr));
NumericLiteral* literal = &caseValue->as<NumericLiteral>();
#ifdef DEBUG
// Use NumberEqualsInt32 here because switches compare using
// strict equality, which will equate -0 and +0. In contrast
// NumberIsInt32 would return false for -0.
int32_t v;
MOZ_ASSERT(mozilla::NumberEqualsInt32(literal->value(), &v));
#endif
int32_t i = int32_t(literal->value());
if (!se.emitCaseBody(i, tableGen)) {
return false;
}
} else {
if (!se.emitCaseBody()) {
return false;
}
}
}
if (!emitTree(caseClause->statementList())) {
return false;
}
}
if (!se.emitEnd()) {
return false;
}
return true;
}
bool BytecodeEmitter::allocateResumeIndex(BytecodeOffset offset,
uint32_t* resumeIndex) {
static constexpr uint32_t MaxResumeIndex = BitMask(24);
static_assert(
MaxResumeIndex < uint32_t(AbstractGeneratorObject::RESUME_INDEX_RUNNING),
"resumeIndex should not include magic AbstractGeneratorObject "
"resumeIndex values");
static_assert(
MaxResumeIndex <= INT32_MAX / sizeof(uintptr_t),
"resumeIndex * sizeof(uintptr_t) must fit in an int32. JIT code relies "
"on this when loading resume entries from BaselineScript");
*resumeIndex = bytecodeSection().resumeOffsetList().length();
if (*resumeIndex > MaxResumeIndex) {
reportError(nullptr, JSMSG_TOO_MANY_RESUME_INDEXES);
return false;
}
return bytecodeSection().resumeOffsetList().append(offset.value());
}
bool BytecodeEmitter::allocateResumeIndexRange(
mozilla::Span<BytecodeOffset> offsets, uint32_t* firstResumeIndex) {
*firstResumeIndex = 0;
for (size_t i = 0, len = offsets.size(); i < len; i++) {
uint32_t resumeIndex;
if (!allocateResumeIndex(offsets[i], &resumeIndex)) {
return false;
}
if (i == 0) {
*firstResumeIndex = resumeIndex;
}
}
return true;
}
bool BytecodeEmitter::emitYieldOp(JSOp op) {
// ParseContext::Scope::setOwnStackSlotCount should check the fixed slot
// for the following, and it should prevent using fixed slot if there are
// too many bindings:
// * generator or asyn function
// * module code after top-level await
MOZ_ASSERT(innermostEmitterScopeNoCheck()->frameSlotEnd() <=
ParseContext::Scope::FixedSlotLimit);
if (op == JSOp::FinalYieldRval) {
return emit1(JSOp::FinalYieldRval);
}
MOZ_ASSERT(op == JSOp::InitialYield || op == JSOp::Yield ||
op == JSOp::Await);
BytecodeOffset off;
if (!emitN(op, 3, &off)) {
return false;
}
if (op == JSOp::InitialYield || op == JSOp::Yield) {
bytecodeSection().addNumYields();
}
uint32_t resumeIndex;
if (!allocateResumeIndex(bytecodeSection().offset(), &resumeIndex)) {
return false;
}
SET_RESUMEINDEX(bytecodeSection().code(off), resumeIndex);
BytecodeOffset unusedOffset;
return emitJumpTargetOp(JSOp::AfterYield, &unusedOffset);
}
bool BytecodeEmitter::emitPushResumeKind(GeneratorResumeKind kind) {
return emit2(JSOp::ResumeKind, uint8_t(kind));
}
bool BytecodeEmitter::emitSetThis(BinaryNode* setThisNode) {
// ParseNodeKind::SetThis is used to update |this| after a super() call
// in a derived class constructor.
MOZ_ASSERT(setThisNode->isKind(ParseNodeKind::SetThis));
MOZ_ASSERT(setThisNode->left()->isKind(ParseNodeKind::Name));
auto name = setThisNode->left()->as<NameNode>().name();
// The 'this' binding is not lexical, but due to super() semantics this
// initialization needs to be treated as a lexical one.
NameLocation loc = lookupName(name);
NameLocation lexicalLoc;
if (loc.kind() == NameLocation::Kind::FrameSlot) {
lexicalLoc = NameLocation::FrameSlot(BindingKind::Let, loc.frameSlot());
} else if (loc.kind() == NameLocation::Kind::EnvironmentCoordinate) {
EnvironmentCoordinate coord = loc.environmentCoordinate();
uint8_t hops = AssertedCast<uint8_t>(coord.hops());
lexicalLoc = NameLocation::EnvironmentCoordinate(BindingKind::Let, hops,
coord.slot());
} else {
MOZ_ASSERT(loc.kind() == NameLocation::Kind::Dynamic);
lexicalLoc = loc;
}
NameOpEmitter noe(this, name, lexicalLoc, NameOpEmitter::Kind::Initialize);
if (!noe.prepareForRhs()) {
// [stack]
return false;
}
// Emit the new |this| value.
if (!emitTree(setThisNode->right())) {
// [stack] NEWTHIS
return false;
}
// Get the original |this| and throw if we already initialized
// it. Do *not* use the NameLocation argument, as that's the special
// lexical location below to deal with super() semantics.
if (!emitGetName(name)) {
// [stack] NEWTHIS THIS
return false;
}
if (!emit1(JSOp::CheckThisReinit)) {
// [stack] NEWTHIS THIS
return false;
}
if (!emit1(JSOp::Pop)) {
// [stack] NEWTHIS
return false;
}
if (!noe.emitAssignment()) {
// [stack] NEWTHIS
return false;
}
if (!emitInitializeInstanceMembers(true)) {
return false;
}
return true;
}
bool BytecodeEmitter::defineHoistedTopLevelFunctions(ParseNode* body) {
MOZ_ASSERT(inPrologue());
MOZ_ASSERT(sc->isGlobalContext() || (sc->isEvalContext() && !sc->strict()));
MOZ_ASSERT(body->is<LexicalScopeNode>() || body->is<ListNode>());
if (body->is<LexicalScopeNode>()) {
body = body->as<LexicalScopeNode>().scopeBody();
MOZ_ASSERT(body->is<ListNode>());
}
if (!body->as<ListNode>().hasTopLevelFunctionDeclarations()) {
return true;
}
return emitHoistedFunctionsInList(&body->as<ListNode>());
}
// For Global and sloppy-Eval scripts, this performs most of the steps of the
// spec's [GlobalDeclarationInstantiation] and [EvalDeclarationInstantiation]
// operations.
//
// Note that while strict-Eval is handled in the same part of the spec, it never
// fails for global-redeclaration checks so those scripts initialize directly in
// their bytecode.
bool BytecodeEmitter::emitDeclarationInstantiation(ParseNode* body) {
if (sc->isModuleContext()) {
// ES Modules have dedicated variable and lexial environments and therefore
// do not have to perform redeclaration checks. We initialize their bindings
// elsewhere in bytecode.
return true;
}
if (sc->isEvalContext() && sc->strict()) {
// Strict Eval has a dedicated variables (and lexical) environment and
// therefore does not have to perform redeclaration checks. We initialize
// their bindings elsewhere in the bytecode.
return true;
}
// If we have no variables bindings, then we are done!
if (sc->isGlobalContext()) {
if (!sc->asGlobalContext()->bindings) {
return true;
}
} else {
MOZ_ASSERT(sc->isEvalContext());
if (!sc->asEvalContext()->bindings) {
return true;
}
}
#if DEBUG
// There should be no emitted functions yet.
for (const auto& thing : perScriptData().gcThingList().objects()) {
MOZ_ASSERT(thing.isEmptyGlobalScope() || thing.isScope());
}
#endif
// Emit the hoisted functions to gc-things list. There is no bytecode
// generated yet to bind them.
if (!defineHoistedTopLevelFunctions(body)) {
return false;
}
// Save the last GCThingIndex emitted. The hoisted functions are contained in
// the gc-things list up until this point. This set of gc-things also contain
// initial scopes (of which there must be at least one).
MOZ_ASSERT(perScriptData().gcThingList().length() > 0);
GCThingIndex lastFun =
GCThingIndex(perScriptData().gcThingList().length() - 1);
#if DEBUG
for (const auto& thing : perScriptData().gcThingList().objects()) {
MOZ_ASSERT(thing.isEmptyGlobalScope() || thing.isScope() ||
thing.isFunction());
}
#endif
// Check for declaration conflicts and initialize the bindings.
// NOTE: The self-hosting top-level script should not populate the builtins
// directly on the GlobalObject (and instead uses JSOp::GetIntrinsic for
// lookups).
if (emitterMode == BytecodeEmitter::EmitterMode::Normal) {
if (!emitGCIndexOp(JSOp::GlobalOrEvalDeclInstantiation, lastFun)) {
return false;
}
}
return true;
}
bool BytecodeEmitter::emitScript(ParseNode* body) {
setScriptStartOffsetIfUnset(body->pn_pos.begin);
MOZ_ASSERT(inPrologue());
TDZCheckCache tdzCache(this);
EmitterScope emitterScope(this);
Maybe<AsyncEmitter> topLevelAwait;
if (sc->isGlobalContext()) {
if (!emitterScope.enterGlobal(this, sc->asGlobalContext())) {
return false;
}
} else if (sc->isEvalContext()) {
if (!emitterScope.enterEval(this, sc->asEvalContext())) {
return false;
}
} else {
MOZ_ASSERT(sc->isModuleContext());
if (!emitterScope.enterModule(this, sc->asModuleContext())) {
return false;
}
if (sc->asModuleContext()->isAsync()) {
topLevelAwait.emplace(this);
}
}
setFunctionBodyEndPos(body->pn_pos.end);
bool isSloppyEval = sc->isEvalContext() && !sc->strict();
if (isSloppyEval && body->is<LexicalScopeNode>() &&
!body->as<LexicalScopeNode>().isEmptyScope()) {
// Sloppy eval scripts may emit hoisted functions bindings with a
// `JSOp::GlobalOrEvalDeclInstantiation` opcode below. If this eval needs a
// top-level lexical environment, we must ensure that environment is created
// before those functions are created and bound.
//
// This differs from the global-script case below because the global-lexical
// environment exists outside the script itself. In the case of strict eval
// scripts, the `emitterScope` above is already sufficient.
EmitterScope lexicalEmitterScope(this);
LexicalScopeNode* scope = &body->as<LexicalScopeNode>();
if (!lexicalEmitterScope.enterLexical(this, ScopeKind::Lexical,
scope->scopeBindings())) {
return false;
}
if (!emitDeclarationInstantiation(scope->scopeBody())) {
return false;
}
switchToMain();
ParseNode* scopeBody = scope->scopeBody();
if (!emitLexicalScopeBody(scopeBody)) {
return false;
}
if (!updateSourceCoordNotes(scopeBody->pn_pos.end)) {
return false;
}
if (!lexicalEmitterScope.leave(this)) {
return false;
}
} else {
if (!emitDeclarationInstantiation(body)) {
return false;
}
if (topLevelAwait) {
if (!topLevelAwait->prepareForModule()) {
return false;
}
}
switchToMain();
if (topLevelAwait) {
if (!topLevelAwait->prepareForBody()) {
return false;
}
}
if (!emitTree(body)) {
// [stack]
return false;
}
if (!updateSourceCoordNotes(body->pn_pos.end)) {
return false;
}
}
if (topLevelAwait) {
if (!topLevelAwait->emitEndModule()) {
return false;
}
}
if (!markSimpleBreakpoint()) {
return false;
}
if (!emitReturnRval()) {
return false;
}
if (!emitterScope.leave(this)) {
return false;
}
if (!NameFunctions(fc, parserAtoms(), body)) {
return false;
}
// Create a Stencil and convert it into a JSScript.
return intoScriptStencil(CompilationStencil::TopLevelIndex);
}
js::UniquePtr<ImmutableScriptData>
BytecodeEmitter::createImmutableScriptData() {
uint32_t nslots;
if (!getNslots(&nslots)) {
return nullptr;
}
bool isFunction = sc->isFunctionBox();
uint16_t funLength = isFunction ? sc->asFunctionBox()->length() : 0;
mozilla::SaturateUint8 propertyCountEstimate = propertyAdditionEstimate;
// Add fields to the property count estimate.
if (isFunction && sc->asFunctionBox()->useMemberInitializers()) {
propertyCountEstimate +=
sc->asFunctionBox()->memberInitializers().numMemberInitializers;
}
return ImmutableScriptData::new_(
fc, mainOffset(), maxFixedSlots, nslots, bodyScopeIndex,
bytecodeSection().numICEntries(), isFunction, funLength,
propertyCountEstimate.value(), bytecodeSection().code(),
bytecodeSection().notes(), bytecodeSection().resumeOffsetList().span(),
bytecodeSection().scopeNoteList().span(),
bytecodeSection().tryNoteList().span());
}
#ifdef ENABLE_DECORATORS
bool BytecodeEmitter::emitCheckIsCallable() {
// This emits code to check if the value at the top of the stack is
// callable. The value is left on the stack.
// [stack] VAL
if (!emitAtomOp(JSOp::GetIntrinsic,
TaggedParserAtomIndex::WellKnown::IsCallable())) {
// [stack] VAL ISCALLABLE
return false;
}
if (!emit1(JSOp::Undefined)) {
// [stack] VAL ISCALLABLE UNDEFINED
return false;
}
if (!emitDupAt(2)) {
// [stack] VAL ISCALLABLE UNDEFINED VAL
return false;
}
return emitCall(JSOp::Call, 1);
// [stack] VAL ISCALLABLE_RESULT
}
#endif
bool BytecodeEmitter::getNslots(uint32_t* nslots) {
uint64_t nslots64 =
maxFixedSlots + static_cast<uint64_t>(bytecodeSection().maxStackDepth());
if (nslots64 > UINT32_MAX) {
reportError(nullptr, JSMSG_NEED_DIET, "script");
return false;
}
*nslots = nslots64;
return true;
}
bool BytecodeEmitter::emitFunctionScript(FunctionNode* funNode) {
MOZ_ASSERT(inPrologue());
ParamsBodyNode* paramsBody = funNode->body();
FunctionBox* funbox = sc->asFunctionBox();
setScriptStartOffsetIfUnset(paramsBody->pn_pos.begin);
// [stack]
FunctionScriptEmitter fse(this, funbox, Some(paramsBody->pn_pos.begin),
Some(paramsBody->pn_pos.end));
if (!fse.prepareForParameters()) {
// [stack]
return false;
}
if (!emitFunctionFormalParameters(paramsBody)) {
// [stack]
return false;
}
if (!fse.prepareForBody()) {
// [stack]
return false;
}
if (!emitTree(paramsBody->body())) {
// [stack]
return false;
}
if (!fse.emitEndBody()) {
// [stack]
return false;
}
if (funbox->index() == CompilationStencil::TopLevelIndex) {
if (!NameFunctions(fc, parserAtoms(), funNode)) {
return false;
}
}
return fse.intoStencil();
}
bool BytecodeEmitter::emitDestructuringLHSRef(ParseNode* target,
size_t* emitted) {
#ifdef DEBUG
int depth = bytecodeSection().stackDepth();
#endif
switch (target->getKind()) {
case ParseNodeKind::Name:
case ParseNodeKind::ArrayExpr:
case ParseNodeKind::ObjectExpr:
// No need to recurse into ParseNodeKind::Array and ParseNodeKind::Object
// subpatterns here, since emitSetOrInitializeDestructuring does the
// recursion when setting or initializing the value. Getting reference
// doesn't recurse.
*emitted = 0;
break;
case ParseNodeKind::ArgumentsLength:
case ParseNodeKind::DotExpr: {
PropertyAccess* prop = &target->as<PropertyAccess>();
bool isSuper = prop->isSuper();
PropOpEmitter poe(this, PropOpEmitter::Kind::SimpleAssignment,
isSuper ? PropOpEmitter::ObjKind::Super
: PropOpEmitter::ObjKind::Other);
if (!poe.prepareForObj()) {
return false;
}
if (isSuper) {
UnaryNode* base = &prop->expression().as<UnaryNode>();
if (!emitGetThisForSuperBase(base)) {
// [stack] THIS SUPERBASE
return false;
}
} else {
if (!emitTree(&prop->expression())) {
// [stack] OBJ
return false;
}
}
if (!poe.prepareForRhs()) {
// [stack] # if Super
// [stack] THIS SUPERBASE
// [stack] # otherwise
// [stack] OBJ
return false;
}
// SUPERBASE was pushed onto THIS in poe.prepareForRhs above.
*emitted = 1 + isSuper;
break;
}
case ParseNodeKind::ElemExpr: {
PropertyByValue* elem = &target->as<PropertyByValue>();
bool isSuper = elem->isSuper();
MOZ_ASSERT(!elem->key().isKind(ParseNodeKind::PrivateName));
ElemOpEmitter eoe(this, ElemOpEmitter::Kind::SimpleAssignment,
isSuper ? ElemOpEmitter::ObjKind::Super
: ElemOpEmitter::ObjKind::Other);
if (!emitElemObjAndKey(elem, isSuper, eoe)) {
// [stack] # if Super
// [stack] THIS KEY
// [stack] # otherwise
// [stack] OBJ KEY
return false;
}
if (!eoe.prepareForRhs()) {
// [stack] # if Super
// [stack] THIS KEY SUPERBASE
// [stack] # otherwise
// [stack] OBJ KEY
return false;
}
// SUPERBASE was pushed onto KEY in eoe.prepareForRhs above.
*emitted = 2 + isSuper;
break;
}
case ParseNodeKind::PrivateMemberExpr: {
PrivateMemberAccess* privateExpr = &target->as<PrivateMemberAccess>();
PrivateOpEmitter xoe(this, PrivateOpEmitter::Kind::SimpleAssignment,
privateExpr->privateName().name());
if (!emitTree(&privateExpr->expression())) {
// [stack] OBJ
return false;
}
if (!xoe.emitReference()) {
// [stack] OBJ NAME
return false;
}
*emitted = xoe.numReferenceSlots();
break;
}
case ParseNodeKind::CallExpr:
MOZ_ASSERT_UNREACHABLE(
"Parser::reportIfNotValidSimpleAssignmentTarget "
"rejects function calls as assignment "
"targets in destructuring assignments");
break;
default:
MOZ_CRASH("emitDestructuringLHSRef: bad lhs kind");
}
MOZ_ASSERT(bytecodeSection().stackDepth() == depth + int(*emitted));
return true;
}
bool BytecodeEmitter::emitSetOrInitializeDestructuring(
ParseNode* target, DestructuringFlavor flav) {
// Now emit the lvalue opcode sequence. If the lvalue is a nested
// destructuring initialiser-form, call ourselves to handle it, then pop
// the matched value. Otherwise emit an lvalue bytecode sequence followed
// by an assignment op.
switch (target->getKind()) {
case ParseNodeKind::ArrayExpr:
case ParseNodeKind::ObjectExpr:
if (!emitDestructuringOps(&target->as<ListNode>(), flav)) {
return false;
}
// emitDestructuringOps leaves the assigned (to-be-destructured) value on
// top of the stack.
break;
case ParseNodeKind::Name: {
auto name = target->as<NameNode>().name();
NameLocation loc = lookupName(name);
NameOpEmitter::Kind kind;
switch (flav) {
case DestructuringFlavor::Declaration:
kind = NameOpEmitter::Kind::Initialize;
break;
case DestructuringFlavor::Assignment:
kind = NameOpEmitter::Kind::SimpleAssignment;
break;
}
NameOpEmitter noe(this, name, loc, kind);
if (!noe.prepareForRhs()) {
// [stack] V ENV?
return false;
}
if (noe.emittedBindOp()) {
// This is like ordinary assignment, but with one difference.
//
// In `a = b`, we first determine a binding for `a` (using
// JSOp::BindName or JSOp::BindGName), then we evaluate `b`, then
// a JSOp::SetName instruction.
//
// In `[a] = [b]`, per spec, `b` is evaluated first, then we
// determine a binding for `a`. Then we need to do assignment--
// but the operands are on the stack in the wrong order for
// JSOp::SetProp, so we have to add a JSOp::Swap.
//
// In the cases where we are emitting a name op, emit a swap
// because of this.
if (!emit1(JSOp::Swap)) {
// [stack] ENV V
return false;
}
} else {
// In cases of emitting a frame slot or environment slot,
// nothing needs be done.
}
if (!noe.emitAssignment()) {
// [stack] V
return false;
}
break;
}
case ParseNodeKind::ArgumentsLength:
case ParseNodeKind::DotExpr: {
// The reference is already pushed by emitDestructuringLHSRef.
// [stack] # if Super
// [stack] THIS SUPERBASE VAL
// [stack] # otherwise
// [stack] OBJ VAL
PropertyAccess* prop = &target->as<PropertyAccess>();
bool isSuper = prop->isSuper();
PropOpEmitter poe(this, PropOpEmitter::Kind::SimpleAssignment,
isSuper ? PropOpEmitter::ObjKind::Super
: PropOpEmitter::ObjKind::Other);
if (!poe.skipObjAndRhs()) {
return false;
}
// [stack] # VAL
if (!poe.emitAssignment(prop->key().atom())) {
return false;
}
break;
}
case ParseNodeKind::ElemExpr: {
// The reference is already pushed by emitDestructuringLHSRef.
// [stack] # if Super
// [stack] THIS KEY SUPERBASE VAL
// [stack] # otherwise
// [stack] OBJ KEY VAL
PropertyByValue* elem = &target->as<PropertyByValue>();
bool isSuper = elem->isSuper();
MOZ_ASSERT(!elem->key().isKind(ParseNodeKind::PrivateName));
ElemOpEmitter eoe(this, ElemOpEmitter::Kind::SimpleAssignment,
isSuper ? ElemOpEmitter::ObjKind::Super
: ElemOpEmitter::ObjKind::Other);
if (!eoe.skipObjAndKeyAndRhs()) {
return false;
}
if (!eoe.emitAssignment()) {
// [stack] VAL
return false;
}
break;
}
case ParseNodeKind::PrivateMemberExpr: {
// The reference is already pushed by emitDestructuringLHSRef.
// [stack] OBJ NAME VAL
PrivateMemberAccess* privateExpr = &target->as<PrivateMemberAccess>();
PrivateOpEmitter xoe(this, PrivateOpEmitter::Kind::SimpleAssignment,
privateExpr->privateName().name());
if (!xoe.skipReference()) {
return false;
}
if (!xoe.emitAssignment()) {
// [stack] VAL
return false;
}
break;
}
case ParseNodeKind::CallExpr:
MOZ_ASSERT_UNREACHABLE(
"Parser::reportIfNotValidSimpleAssignmentTarget "
"rejects function calls as assignment "
"targets in destructuring assignments");
break;
default:
MOZ_CRASH("emitSetOrInitializeDestructuring: bad lhs kind");
}
// Pop the assigned value.
if (!emit1(JSOp::Pop)) {
// [stack] # empty
return false;
}
return true;
}
JSOp BytecodeEmitter::getIterCallOp(JSOp callOp,
SelfHostedIter selfHostedIter) {
if (emitterMode == BytecodeEmitter::SelfHosting) {
MOZ_ASSERT(selfHostedIter != SelfHostedIter::Deny);
switch (callOp) {
case JSOp::Call:
return JSOp::CallContent;
case JSOp::CallIter:
return JSOp::CallContentIter;
default:
MOZ_CRASH("Unknown iterator call op");
}
}
return callOp;
}
bool BytecodeEmitter::emitIteratorNext(
const Maybe<uint32_t>& callSourceCoordOffset,
IteratorKind iterKind /* = IteratorKind::Sync */,
SelfHostedIter selfHostedIter /* = SelfHostedIter::Deny */) {
MOZ_ASSERT(selfHostedIter != SelfHostedIter::Deny ||
emitterMode != BytecodeEmitter::SelfHosting,
".next() iteration is prohibited in self-hosted code because it"
"can run user-modifiable iteration code");
// [stack] ... NEXT ITER
MOZ_ASSERT(bytecodeSection().stackDepth() >= 2);
if (!emitCall(getIterCallOp(JSOp::Call, selfHostedIter), 0,
callSourceCoordOffset)) {
// [stack] ... RESULT
return false;
}
if (iterKind == IteratorKind::Async) {
if (!emitAwaitInInnermostScope()) {
// [stack] ... RESULT
return false;
}
}
if (!emitCheckIsObj(CheckIsObjectKind::IteratorNext)) {
// [stack] ... RESULT
return false;
}
return true;
}
bool BytecodeEmitter::emitIteratorCloseInScope(
EmitterScope& currentScope,
IteratorKind iterKind /* = IteratorKind::Sync */,
CompletionKind completionKind /* = CompletionKind::Normal */,
SelfHostedIter selfHostedIter /* = SelfHostedIter::Deny */) {
MOZ_ASSERT(selfHostedIter != SelfHostedIter::Deny ||
emitterMode != BytecodeEmitter::SelfHosting,
".close() on iterators is prohibited in self-hosted code because "
"it can run user-modifiable iteration code");
if (iterKind == IteratorKind::Sync) {
return emit2(JSOp::CloseIter, uint8_t(completionKind));
}
// Generate inline logic corresponding to IteratorClose (ES2021 7.4.6) and
// AsyncIteratorClose (ES2021 7.4.7). Steps numbers apply to both operations.
//
// Callers need to ensure that the iterator object is at the top of the
// stack.
// For non-Throw completions, we emit the equivalent of:
//
// var returnMethod = GetMethod(iterator, "return");
// if (returnMethod !== undefined) {
// var innerResult = [Await] Call(returnMethod, iterator);
// CheckIsObj(innerResult);
// }
//
// Whereas for Throw completions, we emit:
//
// try {
// var returnMethod = GetMethod(iterator, "return");
// if (returnMethod !== undefined) {
// [Await] Call(returnMethod, iterator);
// }
// } catch {}
Maybe<TryEmitter> tryCatch;
if (completionKind == CompletionKind::Throw) {
tryCatch.emplace(this, TryEmitter::Kind::TryCatch,
TryEmitter::ControlKind::NonSyntactic);
if (!tryCatch->emitTry()) {
// [stack] ... ITER
return false;
}
}
if (!emit1(JSOp::Dup)) {
// [stack] ... ITER ITER
return false;
}
// Steps 1-2 are assertions, step 3 is implicit.
// Step 4.
//
// Get the "return" method.
if (!emitAtomOp(JSOp::GetProp, TaggedParserAtomIndex::WellKnown::return_())) {
// [stack] ... ITER RET
return false;
}
// Step 5.
//
// Do nothing if "return" is undefined or null.
InternalIfEmitter ifReturnMethodIsDefined(this);
if (!emit1(JSOp::IsNullOrUndefined)) {
// [stack] ... ITER RET NULL-OR-UNDEF
return false;
}
if (!ifReturnMethodIsDefined.emitThenElse(
IfEmitter::ConditionKind::Negative)) {
// [stack] ... ITER RET
return false;
}
// Steps 5.c, 7.
//
// Call the "return" method.
if (!emit1(JSOp::Swap)) {
// [stack] ... RET ITER
return false;
}
if (!emitCall(getIterCallOp(JSOp::Call, selfHostedIter), 0)) {
// [stack] ... RESULT
return false;
}
// 7.4.7 AsyncIteratorClose, step 5.d.
if (iterKind == IteratorKind::Async) {
if (completionKind != CompletionKind::Throw) {
// Await clobbers rval, so save the current rval.
if (!emit1(JSOp::GetRval)) {
// [stack] ... RESULT RVAL
return false;
}
if (!emit1(JSOp::Swap)) {
// [stack] ... RVAL RESULT
return false;
}
}
if (!emitAwaitInScope(currentScope)) {
// [stack] ... RVAL? RESULT
return false;
}
if (completionKind != CompletionKind::Throw) {
if (!emit1(JSOp::Swap)) {
// [stack] ... RESULT RVAL
return false;
}
if (!emit1(JSOp::SetRval)) {
// [stack] ... RESULT
return false;
}
}
}
// Step 6 (Handled in caller).
// Step 8.
if (completionKind != CompletionKind::Throw) {
// Check that the "return" result is an object.
if (!emitCheckIsObj(CheckIsObjectKind::IteratorReturn)) {
// [stack] ... RESULT
return false;
}
}
if (!ifReturnMethodIsDefined.emitElse()) {
// [stack] ... ITER RET
return false;
}
if (!emit1(JSOp::Pop)) {
// [stack] ... ITER
return false;
}
if (!ifReturnMethodIsDefined.emitEnd()) {
return false;
}
if (completionKind == CompletionKind::Throw) {
if (!tryCatch->emitCatch()) {
// [stack] ... ITER EXC
return false;
}
// Just ignore the exception thrown by call and await.
if (!emit1(JSOp::Pop)) {
// [stack] ... ITER
return false;
}
if (!tryCatch->emitEnd()) {
// [stack] ... ITER
return false;
}
}
// Step 9 (Handled in caller).
return emit1(JSOp::Pop);
// [stack] ...
}
template <typename InnerEmitter>
bool BytecodeEmitter::wrapWithDestructuringTryNote(int32_t iterDepth,
InnerEmitter emitter) {
MOZ_ASSERT(bytecodeSection().stackDepth() >= iterDepth);
// Pad a nop at the beginning of the bytecode covered by the trynote so
// that when unwinding environments, we may unwind to the scope
// corresponding to the pc *before* the start, in case the first bytecode
// emitted by |emitter| is the start of an inner scope. See comment above
// UnwindEnvironmentToTryPc.
if (!emit1(JSOp::TryDestructuring)) {
return false;
}
BytecodeOffset start = bytecodeSection().offset();
if (!emitter(this)) {
return false;
}
BytecodeOffset end = bytecodeSection().offset();
if (start != end) {
return addTryNote(TryNoteKind::Destructuring, iterDepth, start, end);
}
return true;
}
bool BytecodeEmitter::emitDefault(ParseNode* defaultExpr, ParseNode* pattern) {
// [stack] VALUE
DefaultEmitter de(this);
if (!de.prepareForDefault()) {
// [stack]
return false;
}
if (!emitInitializer(defaultExpr, pattern)) {
// [stack] DEFAULTVALUE
return false;
}
if (!de.emitEnd()) {
// [stack] VALUE/DEFAULTVALUE
return false;
}
return true;
}
bool BytecodeEmitter::emitAnonymousFunctionWithName(
ParseNode* node, TaggedParserAtomIndex name) {
MOZ_ASSERT(node->isDirectRHSAnonFunction());
if (node->is<FunctionNode>()) {
// Function doesn't have 'name' property at this point.
// Set function's name at compile time.
if (!setFunName(node->as<FunctionNode>().funbox(), name)) {
return false;
}
return emitTree(node);
}
MOZ_ASSERT(node->is<ClassNode>());
return emitClass(&node->as<ClassNode>(), ClassNameKind::InferredName, name);
}
bool BytecodeEmitter::emitAnonymousFunctionWithComputedName(
ParseNode* node, FunctionPrefixKind prefixKind) {
MOZ_ASSERT(node->isDirectRHSAnonFunction());
if (node->is<FunctionNode>()) {
if (!emitTree(node)) {
// [stack] NAME FUN
return false;
}
if (!emitDupAt(1)) {
// [stack] NAME FUN NAME
return false;
}
if (!emit2(JSOp::SetFunName, uint8_t(prefixKind))) {
// [stack] NAME FUN
return false;
}
return true;
}
MOZ_ASSERT(node->is<ClassNode>());
MOZ_ASSERT(prefixKind == FunctionPrefixKind::None);
return emitClass(&node->as<ClassNode>(), ClassNameKind::ComputedName);
}
bool BytecodeEmitter::setFunName(FunctionBox* funbox,
TaggedParserAtomIndex name) {
// The inferred name may already be set if this function is an interpreted
// lazy function and we OOM'ed after we set the inferred name the first
// time.
if (funbox->hasInferredName()) {
MOZ_ASSERT(!funbox->emitBytecode);
MOZ_ASSERT(funbox->displayAtom() == name);
return true;
}
funbox->setInferredName(name);
return true;
}
bool BytecodeEmitter::emitInitializer(ParseNode* initializer,
ParseNode* pattern) {
if (initializer->isDirectRHSAnonFunction()) {
MOZ_ASSERT(!pattern->isInParens());
auto name = pattern->as<NameNode>().name();
if (!emitAnonymousFunctionWithName(initializer, name)) {
return false;
}
} else {
if (!emitTree(initializer)) {
return false;
}
}
return true;
}
bool BytecodeEmitter::emitDestructuringOpsArray(ListNode* pattern,
DestructuringFlavor flav) {
MOZ_ASSERT(getSelfHostedIterFor(pattern) == SelfHostedIter::Deny,
"array destructuring is prohibited in self-hosted code because it"
"can run user-modifiable iteration code");
MOZ_ASSERT(pattern->isKind(ParseNodeKind::ArrayExpr));
MOZ_ASSERT(bytecodeSection().stackDepth() != 0);
// Here's pseudo code for |let [a, b, , c=y, ...d] = x;|
//
// Lines that are annotated "covered by trynote" mean that upon throwing
// an exception, IteratorClose is called on iter only if done is false.
//
// let x, y;
// let a, b, c, d;
// let iter, next, lref, result, done, value; // stack values
//
// // NOTE: the fast path for this example is not applicable, because of
// // the spread and the assignment |c=y|, but it is documented here for a
// // simpler example, |let [a,b] = x;|
// //
// // if (IsOptimizableArray(x)) {
// // a = x[0];
// // b = x[1];
// // goto end: // (skip everything below)
// // }
//
// iter = x[Symbol.iterator]();
// next = iter.next;
//
// // ==== emitted by loop for a ====
// lref = GetReference(a); // covered by trynote
//
// result = Call(next, iter);
// done = result.done;
//
// if (done)
// value = undefined;
// else
// value = result.value;
//
// SetOrInitialize(lref, value); // covered by trynote
//
// // ==== emitted by loop for b ====
// lref = GetReference(b); // covered by trynote
//
// if (done) {
// value = undefined;
// } else {
// result = Call(next, iter);
// done = result.done;
// if (done)
// value = undefined;
// else
// value = result.value;
// }
//
// SetOrInitialize(lref, value); // covered by trynote
//
// // ==== emitted by loop for elision ====
// if (done) {
// value = undefined;
// } else {
// result = Call(next, iter);
// done = result.done;
// if (done)
// value = undefined;
// else
// value = result.value;
// }
//
// // ==== emitted by loop for c ====
// lref = GetReference(c); // covered by trynote
//
// if (done) {
// value = undefined;
// } else {
// result = Call(next, iter);
// done = result.done;
// if (done)
// value = undefined;
// else
// value = result.value;
// }
//
// if (value === undefined)
// value = y; // covered by trynote
//
// SetOrInitialize(lref, value); // covered by trynote
//
// // ==== emitted by loop for d ====
// lref = GetReference(d); // covered by trynote
//
// if (done)
// value = [];
// else
// value = [...iter];
//
// SetOrInitialize(lref, value); // covered by trynote
//
// // === emitted after loop ===
// if (!done)
// IteratorClose(iter);
//
// end:
bool isEligibleForArrayOptimizations = true;
for (ParseNode* member : pattern->contents()) {
switch (member->getKind()) {
case ParseNodeKind::Elision:
break;
case ParseNodeKind::Name: {
auto name = member->as<NameNode>().name();
NameLocation loc = lookupName(name);
if (loc.kind() != NameLocation::Kind::ArgumentSlot &&
loc.kind() != NameLocation::Kind::FrameSlot &&
loc.kind() != NameLocation::Kind::EnvironmentCoordinate) {
isEligibleForArrayOptimizations = false;
}
break;
}
default:
// Unfortunately we can't handle any recursive destructuring,
// because we can't guarantee that the recursed-into parts
// won't run code which invalidates our constraints. We also
// cannot handle ParseNodeKind::AssignExpr for similar reasons.
isEligibleForArrayOptimizations = false;
break;
}
if (!isEligibleForArrayOptimizations) {
break;
}
}
// Use an iterator to destructure the RHS, instead of index lookup. We
// must leave the *original* value on the stack.
if (!emit1(JSOp::Dup)) {
// [stack] ... OBJ OBJ
return false;
}
Maybe<InternalIfEmitter> ifArrayOptimizable;
if (isEligibleForArrayOptimizations) {
ifArrayOptimizable.emplace(
this, BranchEmitterBase::LexicalKind::MayContainLexicalAccessInBranch);
if (!emit1(JSOp::Dup)) {
// [stack] OBJ OBJ
return false;
}
if (!emit1(JSOp::OptimizeGetIterator)) {
// [stack] OBJ OBJ IS_OPTIMIZABLE
return false;
}
if (!ifArrayOptimizable->emitThenElse()) {
// [stack] OBJ OBJ
return false;
}
if (!emitAtomOp(JSOp::GetProp,
TaggedParserAtomIndex::WellKnown::length())) {
// [stack] OBJ LENGTH
return false;
}
if (!emit1(JSOp::Swap)) {
// [stack] LENGTH OBJ
return false;
}
uint32_t idx = 0;
for (ParseNode* member : pattern->contents()) {
if (member->isKind(ParseNodeKind::Elision)) {
idx += 1;
continue;
}
if (!emit1(JSOp::Dup)) {
// [stack] LENGTH OBJ OBJ
return false;
}
if (!emitNumberOp(idx)) {
// [stack] LENGTH OBJ OBJ IDX
return false;
}
if (!emit1(JSOp::Dup)) {
// [stack] LENGTH OBJ OBJ IDX IDX
return false;
}
if (!emitDupAt(4)) {
// [stack] LENGTH OBJ OBJ IDX IDX LENGTH
return false;
}
if (!emit1(JSOp::Lt)) {
// [stack] LENGTH OBJ OBJ IDX IS_IN_DENSE_BOUNDS
return false;
}
InternalIfEmitter isInDenseBounds(this);
if (!isInDenseBounds.emitThenElse()) {
// [stack] LENGTH OBJ OBJ IDX
return false;
}
if (!emit1(JSOp::GetElem)) {
// [stack] LENGTH OBJ VALUE
return false;
}
if (!isInDenseBounds.emitElse()) {
// [stack] LENGTH OBJ OBJ IDX
return false;
}
if (!emitPopN(2)) {
// [stack] LENGTH OBJ
return false;
}
if (!emit1(JSOp::Undefined)) {
// [stack] LENGTH OBJ UNDEFINED
return false;
}
if (!isInDenseBounds.emitEnd()) {
// [stack] LENGTH OBJ VALUE|UNDEFINED
return false;
}
if (!emitSetOrInitializeDestructuring(member, flav)) {
// [stack] LENGTH OBJ
return false;
}
idx += 1;
}
if (!emit1(JSOp::Swap)) {
// [stack] OBJ LENGTH
return false;
}
if (!emit1(JSOp::Pop)) {
// [stack] OBJ
return false;
}
if (!ifArrayOptimizable->emitElse()) {
// [stack] OBJ OBJ
return false;
}
}
if (!emitIterator(SelfHostedIter::Deny)) {
// [stack] ... OBJ NEXT ITER
return false;
}
// For an empty pattern [], call IteratorClose unconditionally. Nothing
// else needs to be done.
if (!pattern->head()) {
if (!emit1(JSOp::Swap)) {
// [stack] ... OBJ ITER NEXT
return false;
}
if (!emit1(JSOp::Pop)) {
// [stack] ... OBJ ITER
return false;
}
if (!emitIteratorCloseInInnermostScope()) {
// [stack] ... OBJ
return false;
}
if (ifArrayOptimizable.isSome()) {
if (!ifArrayOptimizable->emitEnd()) {
// [stack] OBJ
return false;
}
}
return true;
}
// Push an initial FALSE value for DONE.
if (!emit1(JSOp::False)) {
// [stack] ... OBJ NEXT ITER FALSE
return false;
}
// TryNoteKind::Destructuring expects the iterator and the done value
// to be the second to top and the top of the stack, respectively.
// IteratorClose is called upon exception only if done is false.
int32_t tryNoteDepth = bytecodeSection().stackDepth();
for (ParseNode* member : pattern->contents()) {
bool isFirst = member == pattern->head();
DebugOnly<bool> hasNext = !!member->pn_next;
ParseNode* subpattern;
if (member->isKind(ParseNodeKind::Spread)) {
subpattern = member->as<UnaryNode>().kid();
MOZ_ASSERT(!subpattern->isKind(ParseNodeKind::AssignExpr));
} else {
subpattern = member;
}
ParseNode* lhsPattern = subpattern;
ParseNode* pndefault = nullptr;
if (subpattern->isKind(ParseNodeKind::AssignExpr)) {
lhsPattern = subpattern->as<AssignmentNode>().left();
pndefault = subpattern->as<AssignmentNode>().right();
}
// Number of stack slots emitted for the LHS reference.
size_t emitted = 0;
// Spec requires LHS reference to be evaluated first.
bool isElision = lhsPattern->isKind(ParseNodeKind::Elision);
if (!isElision) {
auto emitLHSRef = [lhsPattern, &emitted](BytecodeEmitter* bce) {
return bce->emitDestructuringLHSRef(lhsPattern, &emitted);
// [stack] ... OBJ NEXT ITER DONE LREF*
};
if (!wrapWithDestructuringTryNote(tryNoteDepth, emitLHSRef)) {
return false;
}
}
// Pick the DONE value to the top of the stack.
if (emitted) {
if (!emitPickN(emitted)) {
// [stack] ... OBJ NEXT ITER LREF* DONE
return false;
}
}
if (isFirst) {
// If this element is the first, DONE is always FALSE, so pop it.
//
// Non-first elements should emit if-else depending on the
// member pattern, below.
if (!emit1(JSOp::Pop)) {
// [stack] ... OBJ NEXT ITER LREF*
return false;
}
}
if (member->isKind(ParseNodeKind::Spread)) {
InternalIfEmitter ifThenElse(this);
if (!isFirst) {
// If spread is not the first element of the pattern,
// iterator can already be completed.
// [stack] ... OBJ NEXT ITER LREF* DONE
if (!ifThenElse.emitThenElse()) {
// [stack] ... OBJ NEXT ITER LREF*
return false;
}
if (!emitUint32Operand(JSOp::NewArray, 0)) {
// [stack] ... OBJ NEXT ITER LREF* ARRAY
return false;
}
if (!ifThenElse.emitElse()) {
// [stack] ... OBJ NEXT ITER LREF*
return false;
}
}
// If iterator is not completed, create a new array with the rest
// of the iterator.
if (!emitDupAt(emitted + 1, 2)) {
// [stack] ... OBJ NEXT ITER LREF* NEXT ITER
return false;
}
if (!emitUint32Operand(JSOp::NewArray, 0)) {
// [stack] ... OBJ NEXT ITER LREF* NEXT ITER ARRAY
return false;
}
if (!emitNumberOp(0)) {
// [stack] ... OBJ NEXT ITER LREF* NEXT ITER ARRAY INDEX
return false;
}
if (!emitSpread(SelfHostedIter::Deny)) {
// [stack] ... OBJ NEXT ITER LREF* ARRAY INDEX
return false;
}
if (!emit1(JSOp::Pop)) {
// [stack] ... OBJ NEXT ITER LREF* ARRAY
return false;
}
if (!isFirst) {
if (!ifThenElse.emitEnd()) {
return false;
}
MOZ_ASSERT(ifThenElse.pushed() == 1);
}
// At this point the iterator is done. Unpick a TRUE value for DONE above
// ITER.
if (!emit1(JSOp::True)) {
// [stack] ... OBJ NEXT ITER LREF* ARRAY TRUE
return false;
}
if (!emitUnpickN(emitted + 1)) {
// [stack] ... OBJ NEXT ITER TRUE LREF* ARRAY
return false;
}
auto emitAssignment = [lhsPattern, flav](BytecodeEmitter* bce) {
return bce->emitSetOrInitializeDestructuring(lhsPattern, flav);
// [stack] ... OBJ NEXT ITER TRUE
};
if (!wrapWithDestructuringTryNote(tryNoteDepth, emitAssignment)) {
return false;
}
MOZ_ASSERT(!hasNext);
break;
}
InternalIfEmitter ifAlreadyDone(this);
if (!isFirst) {
// [stack] ... OBJ NEXT ITER LREF* DONE
if (!ifAlreadyDone.emitThenElse()) {
// [stack] ... OBJ NEXT ITER LREF*
return false;
}
if (!emit1(JSOp::Undefined)) {
// [stack] ... OBJ NEXT ITER LREF* UNDEF
return false;
}
if (!emit1(JSOp::NopDestructuring)) {
// [stack] ... OBJ NEXT ITER LREF* UNDEF
return false;
}
// The iterator is done. Unpick a TRUE value for DONE above ITER.
if (!emit1(JSOp::True)) {
// [stack] ... OBJ NEXT ITER LREF* UNDEF TRUE
return false;
}
if (!emitUnpickN(emitted + 1)) {
// [stack] ... OBJ NEXT ITER TRUE LREF* UNDEF
return false;
}
if (!ifAlreadyDone.emitElse()) {
// [stack] ... OBJ NEXT ITER LREF*
return false;
}
}
if (!emitDupAt(emitted + 1, 2)) {
// [stack] ... OBJ NEXT ITER LREF* NEXT
return false;
}
if (!emitIteratorNext(Some(pattern->pn_pos.begin))) {
// [stack] ... OBJ NEXT ITER LREF* RESULT
return false;
}
if (!emit1(JSOp::Dup)) {
// [stack] ... OBJ NEXT ITER LREF* RESULT RESULT
return false;
}
if (!emitAtomOp(JSOp::GetProp, TaggedParserAtomIndex::WellKnown::done())) {
// [stack] ... OBJ NEXT ITER LREF* RESULT DONE
return false;
}
if (!emit1(JSOp::Dup)) {
// [stack] ... OBJ NEXT ITER LREF* RESULT DONE DONE
return false;
}
if (!emitUnpickN(emitted + 2)) {
// [stack] ... OBJ NEXT ITER DONE LREF* RESULT DONE
return false;
}
InternalIfEmitter ifDone(this);
if (!ifDone.emitThenElse()) {
// [stack] ... OBJ NEXT ITER DONE LREF* RESULT
return false;
}
if (!emit1(JSOp::Pop)) {
// [stack] ... OBJ NEXT ITER DONE LREF*
return false;
}
if (!emit1(JSOp::Undefined)) {
// [stack] ... OBJ NEXT ITER DONE LREF* UNDEF
return false;
}
if (!emit1(JSOp::NopDestructuring)) {
// [stack] ... OBJ NEXT ITER DONE LREF* UNDEF
return false;
}
if (!ifDone.emitElse()) {
// [stack] ... OBJ NEXT ITER DONE LREF* RESULT
return false;
}
if (!emitAtomOp(JSOp::GetProp, TaggedParserAtomIndex::WellKnown::value())) {
// [stack] ... OBJ NEXT ITER DONE LREF* VALUE
return false;
}
if (!ifDone.emitEnd()) {
return false;
}
MOZ_ASSERT(ifDone.pushed() == 0);
if (!isFirst) {
if (!ifAlreadyDone.emitEnd()) {
return false;
}
MOZ_ASSERT(ifAlreadyDone.pushed() == 2);
}
if (pndefault) {
auto emitDefault = [pndefault, lhsPattern](BytecodeEmitter* bce) {
return bce->emitDefault(pndefault, lhsPattern);
// [stack] ... OBJ NEXT ITER DONE LREF* VALUE
};
if (!wrapWithDestructuringTryNote(tryNoteDepth, emitDefault)) {
return false;
}
}
if (!isElision) {
auto emitAssignment = [lhsPattern, flav](BytecodeEmitter* bce) {
return bce->emitSetOrInitializeDestructuring(lhsPattern, flav);
// [stack] ... OBJ NEXT ITER DONE
};
if (!wrapWithDestructuringTryNote(tryNoteDepth, emitAssignment)) {
return false;
}
} else {
if (!emit1(JSOp::Pop)) {
// [stack] ... OBJ NEXT ITER DONE
return false;
}
}
}
// The last DONE value is on top of the stack. If not DONE, call
// IteratorClose.
// [stack] ... OBJ NEXT ITER DONE
InternalIfEmitter ifDone(this);
if (!ifDone.emitThenElse()) {
// [stack] ... OBJ NEXT ITER
return false;
}
if (!emitPopN(2)) {
// [stack] ... OBJ
return false;
}
if (!ifDone.emitElse()) {
// [stack] ... OBJ NEXT ITER
return false;
}
if (!emit1(JSOp::Swap)) {
// [stack] ... OBJ ITER NEXT
return false;
}
if (!emit1(JSOp::Pop)) {
// [stack] ... OBJ ITER
return false;
}
if (!emitIteratorCloseInInnermostScope()) {
// [stack] ... OBJ
return false;
}
if (!ifDone.emitEnd()) {
return false;
}
if (ifArrayOptimizable.isSome()) {
if (!ifArrayOptimizable->emitEnd()) {
// [stack] OBJ
return false;
}
}
return true;
}
bool BytecodeEmitter::emitComputedPropertyName(UnaryNode* computedPropName) {
MOZ_ASSERT(computedPropName->isKind(ParseNodeKind::ComputedName));
return emitTree(computedPropName->kid()) && emit1(JSOp::ToPropertyKey);
}
bool BytecodeEmitter::emitDestructuringOpsObject(ListNode* pattern,
DestructuringFlavor flav) {
MOZ_ASSERT(pattern->isKind(ParseNodeKind::ObjectExpr));
// [stack] ... RHS
MOZ_ASSERT(bytecodeSection().stackDepth() > 0);
if (!emit1(JSOp::CheckObjCoercible)) {
// [stack] ... RHS
return false;
}
bool needsRestPropertyExcludedSet =
pattern->count() > 1 && pattern->last()->isKind(ParseNodeKind::Spread);
if (needsRestPropertyExcludedSet) {
if (!emitDestructuringObjRestExclusionSet(pattern)) {
// [stack] ... RHS SET
return false;
}
if (!emit1(JSOp::Swap)) {
// [stack] ... SET RHS
return false;
}
}
for (ParseNode* member : pattern->contents()) {
ParseNode* subpattern;
if (member->isKind(ParseNodeKind::MutateProto) ||
member->isKind(ParseNodeKind::Spread)) {
subpattern = member->as<UnaryNode>().kid();
MOZ_ASSERT_IF(member->isKind(ParseNodeKind::Spread),
!subpattern->isKind(ParseNodeKind::AssignExpr));
} else {
MOZ_ASSERT(member->isKind(ParseNodeKind::PropertyDefinition) ||
member->isKind(ParseNodeKind::Shorthand));
subpattern = member->as<BinaryNode>().right();
}
ParseNode* lhs = subpattern;
ParseNode* pndefault = nullptr;
if (subpattern->isKind(ParseNodeKind::AssignExpr)) {
lhs = subpattern->as<AssignmentNode>().left();
pndefault = subpattern->as<AssignmentNode>().right();
}
// Number of stack slots emitted for the LHS reference.
size_t emitted = 0;
// Spec requires LHS reference to be evaluated first.
if (!emitDestructuringLHSRef(lhs, &emitted)) {
// [stack] ... SET? RHS LREF*
return false;
}
// Duplicate the value being destructured to use as a reference base.
if (!emitDupAt(emitted)) {
// [stack] ... SET? RHS LREF* RHS
return false;
}
if (member->isKind(ParseNodeKind::Spread)) {
if (!updateSourceCoordNotes(member->pn_pos.begin)) {
return false;
}
if (!emit1(JSOp::NewInit)) {
// [stack] ... SET? RHS LREF* RHS TARGET
return false;
}
if (!emit1(JSOp::Dup)) {
// [stack] ... SET? RHS LREF* RHS TARGET TARGET
return false;
}
if (!emit2(JSOp::Pick, 2)) {
// [stack] ... SET? RHS LREF* TARGET TARGET RHS
return false;
}
if (needsRestPropertyExcludedSet) {
if (!emit2(JSOp::Pick, emitted + 4)) {
// [stack] ... RHS LREF* TARGET TARGET RHS SET
return false;
}
}
CopyOption option = needsRestPropertyExcludedSet ? CopyOption::Filtered
: CopyOption::Unfiltered;
if (!emitCopyDataProperties(option)) {
// [stack] ... RHS LREF* TARGET
return false;
}
// Destructure TARGET per this member's lhs.
if (!emitSetOrInitializeDestructuring(lhs, flav)) {
// [stack] ... RHS
return false;
}
MOZ_ASSERT(member == pattern->last(), "Rest property is always last");
break;
}
// Now push the property value currently being matched, which is the value
// of the current property name "label" on the left of a colon in the object
// initialiser.
if (member->isKind(ParseNodeKind::MutateProto)) {
if (!emitAtomOp(JSOp::GetProp,
TaggedParserAtomIndex::WellKnown::proto_())) {
// [stack] ... SET? RHS LREF* PROP
return false;
}
} else {
MOZ_ASSERT(member->isKind(ParseNodeKind::PropertyDefinition) ||
member->isKind(ParseNodeKind::Shorthand));
ParseNode* key = member->as<BinaryNode>().left();
if (key->isKind(ParseNodeKind::ObjectPropertyName) ||
key->isKind(ParseNodeKind::StringExpr)) {
if (!emitAtomOp(JSOp::GetProp, key->as<NameNode>().atom())) {
// [stack] ... SET? RHS LREF* PROP
return false;
}
} else {
if (key->isKind(ParseNodeKind::NumberExpr)) {
if (!emitNumberOp(key->as<NumericLiteral>().value())) {
// [stack]... SET? RHS LREF* RHS KEY
return false;
}
} else {
// Otherwise this is a computed property name. BigInt keys are parsed
// as (synthetic) computed property names, too.
MOZ_ASSERT(key->isKind(ParseNodeKind::ComputedName));
if (!emitComputedPropertyName(&key->as<UnaryNode>())) {
// [stack] ... SET? RHS LREF* RHS KEY
return false;
}
// Add the computed property key to the exclusion set.
if (needsRestPropertyExcludedSet) {
if (!emitDupAt(emitted + 3)) {
// [stack] ... SET RHS LREF* RHS KEY SET
return false;
}
if (!emitDupAt(1)) {
// [stack] ... SET RHS LREF* RHS KEY SET KEY
return false;
}
if (!emit1(JSOp::Undefined)) {
// [stack] ... SET RHS LREF* RHS KEY SET KEY UNDEFINED
return false;
}
if (!emit1(JSOp::InitElem)) {
// [stack] ... SET RHS LREF* RHS KEY SET
return false;
}
if (!emit1(JSOp::Pop)) {
// [stack] ... SET RHS LREF* RHS KEY
return false;
}
}
}
// Get the property value.
if (!emitElemOpBase(JSOp::GetElem)) {
// [stack] ... SET? RHS LREF* PROP
return false;
}
}
}
if (pndefault) {
if (!emitDefault(pndefault, lhs)) {
// [stack] ... SET? RHS LREF* VALUE
return false;
}
}
// Destructure PROP per this member's lhs.
if (!emitSetOrInitializeDestructuring(lhs, flav)) {
// [stack] ... SET? RHS
return false;
}
}
return true;
}
static bool IsDestructuringRestExclusionSetObjLiteralCompatible(
ListNode* pattern) {
uint32_t propCount = 0;
for (ParseNode* member : pattern->contents()) {
if (member->isKind(ParseNodeKind::Spread)) {
MOZ_ASSERT(!member->pn_next, "unexpected trailing element after spread");
break;
}
propCount++;
if (member->isKind(ParseNodeKind::MutateProto)) {
continue;
}
ParseNode* key = member->as<BinaryNode>().left();
if (key->isKind(ParseNodeKind::ObjectPropertyName) ||
key->isKind(ParseNodeKind::StringExpr)) {
continue;
}
// Number and BigInt keys aren't yet supported. Computed property names need
// to be added dynamically.
MOZ_ASSERT(key->isKind(ParseNodeKind::NumberExpr) ||
key->isKind(ParseNodeKind::BigIntExpr) ||
key->isKind(ParseNodeKind::ComputedName));
return false;
}
if (propCount > SharedPropMap::MaxPropsForNonDictionary) {
// JSOp::NewObject cannot accept dictionary-mode objects.
return false;
}
return true;
}
bool BytecodeEmitter::emitDestructuringObjRestExclusionSet(ListNode* pattern) {
MOZ_ASSERT(pattern->isKind(ParseNodeKind::ObjectExpr));
MOZ_ASSERT(pattern->last()->isKind(ParseNodeKind::Spread));
// See if we can use ObjLiteral to construct the exclusion set object.
if (IsDestructuringRestExclusionSetObjLiteralCompatible(pattern)) {
if (!emitDestructuringRestExclusionSetObjLiteral(pattern)) {
// [stack] OBJ
return false;
}
} else {
// Take the slow but sure way and start off with a blank object.
if (!emit1(JSOp::NewInit)) {
// [stack] OBJ
return false;
}
}
for (ParseNode* member : pattern->contents()) {
if (member->isKind(ParseNodeKind::Spread)) {
MOZ_ASSERT(!member->pn_next, "unexpected trailing element after spread");
break;
}
TaggedParserAtomIndex pnatom;
if (member->isKind(ParseNodeKind::MutateProto)) {
pnatom = TaggedParserAtomIndex::WellKnown::proto_();
} else {
ParseNode* key = member->as<BinaryNode>().left();
if (key->isKind(ParseNodeKind::ObjectPropertyName) ||
key->isKind(ParseNodeKind::StringExpr)) {
pnatom = key->as<NameNode>().atom();
} else if (key->isKind(ParseNodeKind::NumberExpr)) {
if (!emitNumberOp(key->as<NumericLiteral>().value())) {
return false;
}
} else {
// Otherwise this is a computed property name which needs to be added
// dynamically. BigInt keys are parsed as (synthetic) computed property
// names, too.
MOZ_ASSERT(key->isKind(ParseNodeKind::ComputedName));
continue;
}
}
// Initialize elements with |undefined|.
if (!emit1(JSOp::Undefined)) {
return false;
}
if (!pnatom) {
if (!emit1(JSOp::InitElem)) {
return false;
}
} else {
if (!emitAtomOp(JSOp::InitProp, pnatom)) {
return false;
}
}
}
return true;
}
bool BytecodeEmitter::emitDestructuringOps(ListNode* pattern,
DestructuringFlavor flav) {
if (pattern->isKind(ParseNodeKind::ArrayExpr)) {
return emitDestructuringOpsArray(pattern, flav);
}
return emitDestructuringOpsObject(pattern, flav);
}
bool BytecodeEmitter::emitTemplateString(ListNode* templateString) {
bool pushedString = false;
for (ParseNode* item : templateString->contents()) {
bool isString = (item->getKind() == ParseNodeKind::StringExpr ||
item->getKind() == ParseNodeKind::TemplateStringExpr);
// Skip empty strings. These are very common: a template string like
// `${a}${b}` has three empty strings and without this optimization
// we'd emit four JSOp::Add operations instead of just one.
if (isString && item->as<NameNode>().atom() ==
TaggedParserAtomIndex::WellKnown::empty()) {
continue;
}
if (!isString) {
// We update source notes before emitting the expression
if (!updateSourceCoordNotes(item->pn_pos.begin)) {
return false;
}
}
if (!emitTree(item)) {
return false;
}
if (!isString) {
// We need to convert the expression to a string
if (!emit1(JSOp::ToString)) {
return false;
}
}
if (pushedString) {
// We've pushed two strings onto the stack. Add them together, leaving
// just one.
if (!emit1(JSOp::Add)) {
return false;
}
} else {
pushedString = true;
}
}
if (!pushedString) {
// All strings were empty, this can happen for something like `${""}`.
// Just push an empty string.
if (!emitStringOp(JSOp::String,
TaggedParserAtomIndex::WellKnown::empty())) {
return false;
}
}
return true;
}
bool BytecodeEmitter::emitDeclarationList(ListNode* declList) {
for (ParseNode* decl : declList->contents()) {
ParseNode* pattern;
ParseNode* initializer;
if (decl->isKind(ParseNodeKind::Name)) {
pattern = decl;
initializer = nullptr;
} else {
AssignmentNode* assignNode = &decl->as<AssignmentNode>();
pattern = assignNode->left();
initializer = assignNode->right();
}
if (pattern->isKind(ParseNodeKind::Name)) {
// initializer can be null here.
if (!emitSingleDeclaration(declList, &pattern->as<NameNode>(),
initializer)) {
return false;
}
} else {
MOZ_ASSERT(pattern->isKind(ParseNodeKind::ArrayExpr) ||
pattern->isKind(ParseNodeKind::ObjectExpr));
MOZ_ASSERT(initializer != nullptr);
if (!updateSourceCoordNotes(initializer->pn_pos.begin)) {
return false;
}
if (!markStepBreakpoint()) {
return false;
}
if (!emitTree(initializer)) {
return false;
}
if (!emitDestructuringOps(&pattern->as<ListNode>(),
DestructuringFlavor::Declaration)) {
return false;
}
if (!emit1(JSOp::Pop)) {
return false;
}
}
}
return true;
}
bool BytecodeEmitter::emitSingleDeclaration(ListNode* declList, NameNode* decl,
ParseNode* initializer) {
MOZ_ASSERT(decl->isKind(ParseNodeKind::Name));
// Nothing to do for initializer-less 'var' declarations, as there's no TDZ.
if (!initializer && declList->isKind(ParseNodeKind::VarStmt)) {
return true;
}
auto nameAtom = decl->name();
NameOpEmitter noe(this, nameAtom, NameOpEmitter::Kind::Initialize);
if (!noe.prepareForRhs()) {
// [stack] ENV?
return false;
}
if (!initializer) {
// Lexical declarations are initialized to undefined without an
// initializer.
MOZ_ASSERT(declList->isKind(ParseNodeKind::LetDecl),
"var declarations without initializers handled above, "
"and const declarations must have initializers");
if (!emit1(JSOp::Undefined)) {
// [stack] ENV? UNDEF
return false;
}
} else {
MOZ_ASSERT(initializer);
if (!updateSourceCoordNotes(initializer->pn_pos.begin)) {
return false;
}
if (!markStepBreakpoint()) {
return false;
}
if (!emitInitializer(initializer, decl)) {
// [stack] ENV? V
return false;
}
}
if (!noe.emitAssignment()) {
// [stack] V
return false;
}
if (!emit1(JSOp::Pop)) {
// [stack]
return false;
}
return true;
}
bool BytecodeEmitter::emitAssignmentRhs(
ParseNode* rhs, TaggedParserAtomIndex anonFunctionName) {
if (rhs->isDirectRHSAnonFunction()) {
if (anonFunctionName) {
return emitAnonymousFunctionWithName(rhs, anonFunctionName);
}
return emitAnonymousFunctionWithComputedName(rhs, FunctionPrefixKind::None);
}
return emitTree(rhs);
}
// The RHS value to assign is already on the stack, i.e., the next enumeration
// value in a for-in or for-of loop. Offset is the location in the stack of the
// already-emitted rhs. If we emitted a JSOp::BindName or JSOp::BindGName, then
// the scope is on the top of the stack and we need to dig one deeper to get
// the right RHS value.
bool BytecodeEmitter::emitAssignmentRhs(uint8_t offset) {
if (offset != 1) {
return emitPickN(offset - 1);
}
return true;
}
static inline JSOp CompoundAssignmentParseNodeKindToJSOp(ParseNodeKind pnk) {
switch (pnk) {
case ParseNodeKind::InitExpr:
return JSOp::Nop;
case ParseNodeKind::AssignExpr:
return JSOp::Nop;
case ParseNodeKind::AddAssignExpr:
return JSOp::Add;
case ParseNodeKind::SubAssignExpr:
return JSOp::Sub;
case ParseNodeKind::BitOrAssignExpr:
return JSOp::BitOr;
case ParseNodeKind::BitXorAssignExpr:
return JSOp::BitXor;
case ParseNodeKind::BitAndAssignExpr:
return JSOp::BitAnd;
case ParseNodeKind::LshAssignExpr:
return JSOp::Lsh;
case ParseNodeKind::RshAssignExpr:
return JSOp::Rsh;
case ParseNodeKind::UrshAssignExpr:
return JSOp::Ursh;
case ParseNodeKind::MulAssignExpr:
return JSOp::Mul;
case ParseNodeKind::DivAssignExpr:
return JSOp::Div;
case ParseNodeKind::ModAssignExpr:
return JSOp::Mod;
case ParseNodeKind::PowAssignExpr:
return JSOp::Pow;
case ParseNodeKind::CoalesceAssignExpr:
case ParseNodeKind::OrAssignExpr:
case ParseNodeKind::AndAssignExpr:
// Short-circuit assignment operators are handled elsewhere.
[[fallthrough]];
default:
MOZ_CRASH("unexpected compound assignment op");
}
}
bool BytecodeEmitter::emitAssignmentOrInit(ParseNodeKind kind, ParseNode* lhs,
ParseNode* rhs) {
JSOp compoundOp = CompoundAssignmentParseNodeKindToJSOp(kind);
bool isCompound = compoundOp != JSOp::Nop;
bool isInit = kind == ParseNodeKind::InitExpr;
// We estimate the number of properties this could create
// if used as constructor merely by counting this.foo = assignment
// or init expressions;
//
// This currently doesn't handle this[x] = foo;
if (isInit || kind == ParseNodeKind::AssignExpr) {
if (lhs->isKind(ParseNodeKind::DotExpr)) {
if (lhs->as<PropertyAccess>().expression().isKind(
ParseNodeKind::ThisExpr)) {
propertyAdditionEstimate++;
}
}
}
MOZ_ASSERT_IF(isInit, lhs->isKind(ParseNodeKind::DotExpr) ||
lhs->isKind(ParseNodeKind::ElemExpr) ||
lhs->isKind(ParseNodeKind::PrivateMemberExpr));
// |name| is used within NameOpEmitter, so its lifetime must surpass |noe|.
TaggedParserAtomIndex name;
Maybe<NameOpEmitter> noe;
Maybe<PropOpEmitter> poe;
Maybe<ElemOpEmitter> eoe;
Maybe<PrivateOpEmitter> xoe;
// Deal with non-name assignments.
uint8_t offset = 1;
// Purpose of anonFunctionName:
//
// In normal name assignments (`f = function(){}`), an anonymous function gets
// an inferred name based on the left-hand side name node.
//
// In normal property assignments (`obj.x = function(){}`), the anonymous
// function does not have a computed name, and rhs->isDirectRHSAnonFunction()
// will be false (and anonFunctionName will not be used). However, in field
// initializers (`class C { x = function(){} }`), field initialization is
// implemented via a property or elem assignment (where we are now), and
// rhs->isDirectRHSAnonFunction() is set - so we'll assign the name of the
// function.
TaggedParserAtomIndex anonFunctionName;
switch (lhs->getKind()) {
case ParseNodeKind::Name: {
name = lhs->as<NameNode>().name();
anonFunctionName = name;
noe.emplace(this, name,
isCompound ? NameOpEmitter::Kind::CompoundAssignment
: NameOpEmitter::Kind::SimpleAssignment);
break;
}
case ParseNodeKind::ArgumentsLength:
case ParseNodeKind::DotExpr: {
PropertyAccess* prop = &lhs->as<PropertyAccess>();
bool isSuper = prop->isSuper();
poe.emplace(this,
isCompound ? PropOpEmitter::Kind::CompoundAssignment
: isInit ? PropOpEmitter::Kind::PropInit
: PropOpEmitter::Kind::SimpleAssignment,
isSuper ? PropOpEmitter::ObjKind::Super
: PropOpEmitter::ObjKind::Other);
if (!poe->prepareForObj()) {
return false;
}
anonFunctionName = prop->name();
if (isSuper) {
UnaryNode* base = &prop->expression().as<UnaryNode>();
if (!emitGetThisForSuperBase(base)) {
// [stack] THIS SUPERBASE
return false;
}
// SUPERBASE is pushed onto THIS later in poe->emitGet below.
offset += 2;
} else {
if (!emitTree(&prop->expression())) {
// [stack] OBJ
return false;
}
offset += 1;
}
break;
}
case ParseNodeKind::ElemExpr: {
PropertyByValue* elem = &lhs->as<PropertyByValue>();
bool isSuper = elem->isSuper();
MOZ_ASSERT(!elem->key().isKind(ParseNodeKind::PrivateName));
eoe.emplace(this,
isCompound ? ElemOpEmitter::Kind::CompoundAssignment
: isInit ? ElemOpEmitter::Kind::PropInit
: ElemOpEmitter::Kind::SimpleAssignment,
isSuper ? ElemOpEmitter::ObjKind::Super
: ElemOpEmitter::ObjKind::Other);
if (!emitElemObjAndKey(elem, isSuper, *eoe)) {
// [stack] # if Super
// [stack] THIS KEY
// [stack] # otherwise
// [stack] OBJ KEY
return false;
}
if (isSuper) {
// SUPERBASE is pushed onto KEY in eoe->emitGet below.
offset += 3;
} else {
offset += 2;
}
break;
}
case ParseNodeKind::PrivateMemberExpr: {
PrivateMemberAccess* privateExpr = &lhs->as<PrivateMemberAccess>();
xoe.emplace(this,
isCompound ? PrivateOpEmitter::Kind::CompoundAssignment
: isInit ? PrivateOpEmitter::Kind::PropInit
: PrivateOpEmitter::Kind::SimpleAssignment,
privateExpr->privateName().name());
if (!emitTree(&privateExpr->expression())) {
// [stack] OBJ
return false;
}
if (!xoe->emitReference()) {
// [stack] OBJ KEY
return false;
}
offset += xoe->numReferenceSlots();
break;
}
case ParseNodeKind::ArrayExpr:
case ParseNodeKind::ObjectExpr:
break;
case ParseNodeKind::CallExpr:
if (!emitTree(lhs)) {
return false;
}
// Assignment to function calls is forbidden, but we have to make the
// call first. Now we can throw.
if (!emit2(JSOp::ThrowMsg, uint8_t(ThrowMsgKind::AssignToCall))) {
return false;
}
// Rebalance the stack to placate stack-depth assertions.
if (!emit1(JSOp::Pop)) {
return false;
}
break;
default:
MOZ_ASSERT(0);
}
if (isCompound) {
MOZ_ASSERT(rhs);
switch (lhs->getKind()) {
case ParseNodeKind::ArgumentsLength:
case ParseNodeKind::DotExpr: {
PropertyAccess* prop = &lhs->as<PropertyAccess>();
if (!poe->emitGet(prop->key().atom())) {
// [stack] # if Super
// [stack] THIS SUPERBASE PROP
// [stack] # otherwise
// [stack] OBJ PROP
return false;
}
break;
}
case ParseNodeKind::ElemExpr: {
if (!eoe->emitGet()) {
// [stack] KEY THIS OBJ ELEM
return false;
}
break;
}
case ParseNodeKind::PrivateMemberExpr: {
if (!xoe->emitGet()) {
// [stack] OBJ KEY VALUE
return false;
}
break;
}
case ParseNodeKind::CallExpr:
// We just emitted a JSOp::ThrowMsg and popped the call's return
// value. Push a random value to make sure the stack depth is
// correct.
if (!emit1(JSOp::Null)) {
// [stack] NULL
return false;
}
break;
default:;
}
}
switch (lhs->getKind()) {
case ParseNodeKind::Name:
if (!noe->prepareForRhs()) {
// [stack] ENV? VAL?
return false;
}
offset += noe->emittedBindOp();
break;
case ParseNodeKind::ArgumentsLength:
case ParseNodeKind::DotExpr:
if (!poe->prepareForRhs()) {
// [stack] # if Simple Assignment with Super
// [stack] THIS SUPERBASE
// [stack] # if Simple Assignment with other
// [stack] OBJ
// [stack] # if Compound Assignment with Super
// [stack] THIS SUPERBASE PROP
// [stack] # if Compound Assignment with other
// [stack] OBJ PROP
return false;
}
break;
case ParseNodeKind::ElemExpr:
if (!eoe->prepareForRhs()) {
// [stack] # if Simple Assignment with Super
// [stack] THIS KEY SUPERBASE
// [stack] # if Simple Assignment with other
// [stack] OBJ KEY
// [stack] # if Compound Assignment with Super
// [stack] THIS KEY SUPERBASE ELEM
// [stack] # if Compound Assignment with other
// [stack] OBJ KEY ELEM
return false;
}
break;
case ParseNodeKind::PrivateMemberExpr:
// no stack adjustment needed
break;
default:
break;
}
if (rhs) {
if (!emitAssignmentRhs(rhs, anonFunctionName)) {
// [stack] ... VAL? RHS
return false;
}
} else {
// Assumption: Things with pre-emitted RHS values never need to be named.
if (!emitAssignmentRhs(offset)) {
// [stack] ... VAL? RHS
return false;
}
}
/* If += etc., emit the binary operator with a hint for the decompiler. */
if (isCompound) {
if (!emit1(compoundOp)) {
// [stack] ... VAL
return false;
}
if (!emit1(JSOp::NopIsAssignOp)) {
// [stack] ... VAL
return false;
}
}
/* Finally, emit the specialized assignment bytecode. */
switch (lhs->getKind()) {
case ParseNodeKind::Name: {
if (!noe->emitAssignment()) {
// [stack] VAL
return false;
}
break;
}
case ParseNodeKind::ArgumentsLength:
case ParseNodeKind::DotExpr: {
PropertyAccess* prop = &lhs->as<PropertyAccess>();
if (!poe->emitAssignment(prop->key().atom())) {
// [stack] VAL
return false;
}
break;
}
case ParseNodeKind::CallExpr:
// We threw above, so nothing to do here.
break;
case ParseNodeKind::ElemExpr: {
if (!eoe->emitAssignment()) {
// [stack] VAL
return false;
}
break;
}
case ParseNodeKind::PrivateMemberExpr:
if (!xoe->emitAssignment()) {
// [stack] VAL
return false;
}
break;
case ParseNodeKind::ArrayExpr:
case ParseNodeKind::ObjectExpr:
if (!emitDestructuringOps(&lhs->as<ListNode>(),
DestructuringFlavor::Assignment)) {
return false;
}
break;
default:
MOZ_ASSERT(0);
}
return true;
}
bool BytecodeEmitter::emitShortCircuitAssignment(AssignmentNode* node) {
TDZCheckCache tdzCache(this);
JSOp op;
switch (node->getKind()) {
case ParseNodeKind::CoalesceAssignExpr:
op = JSOp::Coalesce;
break;
case ParseNodeKind::OrAssignExpr:
op = JSOp::Or;
break;
case ParseNodeKind::AndAssignExpr:
op = JSOp::And;
break;
default:
MOZ_CRASH("Unexpected ParseNodeKind");
}
ParseNode* lhs = node->left();
ParseNode* rhs = node->right();
// |name| is used within NameOpEmitter, so its lifetime must surpass |noe|.
TaggedParserAtomIndex name;
// Select the appropriate emitter based on the left-hand side.
Maybe<NameOpEmitter> noe;
Maybe<PropOpEmitter> poe;
Maybe<ElemOpEmitter> eoe;
Maybe<PrivateOpEmitter> xoe;
int32_t depth = bytecodeSection().stackDepth();
// Number of values pushed onto the stack in addition to the lhs value.
int32_t numPushed;
// Evaluate the left-hand side expression and compute any stack values needed
// for the assignment.
switch (lhs->getKind()) {
case ParseNodeKind::Name: {
name = lhs->as<NameNode>().name();
noe.emplace(this, name, NameOpEmitter::Kind::CompoundAssignment);
if (!noe->prepareForRhs()) {
// [stack] ENV? LHS
return false;
}
numPushed = noe->emittedBindOp();
break;
}
case ParseNodeKind::ArgumentsLength:
case ParseNodeKind::DotExpr: {
PropertyAccess* prop = &lhs->as<PropertyAccess>();
bool isSuper = prop->isSuper();
poe.emplace(this, PropOpEmitter::Kind::CompoundAssignment,
isSuper ? PropOpEmitter::ObjKind::Super
: PropOpEmitter::ObjKind::Other);
if (!poe->prepareForObj()) {
return false;
}
if (isSuper) {
UnaryNode* base = &prop->expression().as<UnaryNode>();
if (!emitGetThisForSuperBase(base)) {
// [stack] THIS SUPERBASE
return false;
}
} else {
if (!emitTree(&prop->expression())) {
// [stack] OBJ
return false;
}
}
if (!poe->emitGet(prop->key().atom())) {
// [stack] # if Super
// [stack] THIS SUPERBASE LHS
// [stack] # otherwise
// [stack] OBJ LHS
return false;
}
if (!poe->prepareForRhs()) {
// [stack] # if Super
// [stack] THIS SUPERBASE LHS
// [stack] # otherwise
// [stack] OBJ LHS
return false;
}
numPushed = 1 + isSuper;
break;
}
case ParseNodeKind::ElemExpr: {
PropertyByValue* elem = &lhs->as<PropertyByValue>();
bool isSuper = elem->isSuper();
MOZ_ASSERT(!elem->key().isKind(ParseNodeKind::PrivateName));
eoe.emplace(this, ElemOpEmitter::Kind::CompoundAssignment,
isSuper ? ElemOpEmitter::ObjKind::Super
: ElemOpEmitter::ObjKind::Other);
if (!emitElemObjAndKey(elem, isSuper, *eoe)) {
// [stack] # if Super
// [stack] THIS KEY
// [stack] # otherwise
// [stack] OBJ KEY
return false;
}
if (!eoe->emitGet()) {
// [stack] # if Super
// [stack] THIS KEY SUPERBASE LHS
// [stack] # otherwise
// [stack] OBJ KEY LHS
return false;
}
if (!eoe->prepareForRhs()) {
// [stack] # if Super
// [stack] THIS KEY SUPERBASE LHS
// [stack] # otherwise
// [stack] OBJ KEY LHS
return false;
}
numPushed = 2 + isSuper;
break;
}
case ParseNodeKind::PrivateMemberExpr: {
PrivateMemberAccess* privateExpr = &lhs->as<PrivateMemberAccess>();
xoe.emplace(this, PrivateOpEmitter::Kind::CompoundAssignment,
privateExpr->privateName().name());
if (!emitTree(&privateExpr->expression())) {
// [stack] OBJ
return false;
}
if (!xoe->emitReference()) {
// [stack] OBJ NAME
return false;
}
if (!xoe->emitGet()) {
// [stack] OBJ NAME LHS
return false;
}
numPushed = xoe->numReferenceSlots();
break;
}
default:
MOZ_CRASH();
}
MOZ_ASSERT(bytecodeSection().stackDepth() == depth + numPushed + 1);
// Test for the short-circuit condition.
JumpList jump;
if (!emitJump(op, &jump)) {
// [stack] ... LHS
return false;
}
// The short-circuit condition wasn't fulfilled, pop the left-hand side value
// which was kept on the stack.
if (!emit1(JSOp::Pop)) {
// [stack] ...
return false;
}
if (!emitAssignmentRhs(rhs, name)) {
// [stack] ... RHS
return false;
}
// Perform the actual assignment.
switch (lhs->getKind()) {
case ParseNodeKind::Name: {
if (!noe->emitAssignment()) {
// [stack] RHS
return false;
}
break;
}
case ParseNodeKind::ArgumentsLength:
case ParseNodeKind::DotExpr: {
PropertyAccess* prop = &lhs->as<PropertyAccess>();
if (!poe->emitAssignment(prop->key().atom())) {
// [stack] RHS
return false;
}
break;
}
case ParseNodeKind::ElemExpr: {
if (!eoe->emitAssignment()) {
// [stack] RHS
return false;
}
break;
}
case ParseNodeKind::PrivateMemberExpr:
if (!xoe->emitAssignment()) {
// [stack] RHS
return false;
}
break;
default:
MOZ_CRASH();
}
MOZ_ASSERT(bytecodeSection().stackDepth() == depth + 1);
// Join with the short-circuit jump and pop anything left on the stack.
if (numPushed > 0) {
JumpList jumpAroundPop;
if (!emitJump(JSOp::Goto, &jumpAroundPop)) {
// [stack] RHS
return false;
}
if (!emitJumpTargetAndPatch(jump)) {
// [stack] ... LHS
return false;
}
// Reconstruct the stack depth after the jump.
bytecodeSection().setStackDepth(depth + 1 + numPushed);
// Move the left-hand side value to the bottom and pop the rest.
if (!emitUnpickN(numPushed)) {
// [stack] LHS ...
return false;
}
if (!emitPopN(numPushed)) {
// [stack] LHS
return false;
}
if (!emitJumpTargetAndPatch(jumpAroundPop)) {
// [stack] LHS | RHS
return false;
}
} else {
if (!emitJumpTargetAndPatch(jump)) {
// [stack] LHS | RHS
return false;
}
}
MOZ_ASSERT(bytecodeSection().stackDepth() == depth + 1);
return true;
}
bool BytecodeEmitter::emitCallSiteObjectArray(ObjLiteralWriter& writer,
ListNode* cookedOrRaw,
ParseNode* head, uint32_t count) {
DebugOnly<size_t> idx = 0;
for (ParseNode* pn : cookedOrRaw->contentsFrom(head)) {
MOZ_ASSERT(pn->isKind(ParseNodeKind::TemplateStringExpr) ||
pn->isKind(ParseNodeKind::RawUndefinedExpr));
if (!emitObjLiteralValue(writer, pn)) {
return false;
}
idx++;
}
MOZ_ASSERT(idx == count);
return true;
}
bool BytecodeEmitter::emitCallSiteObject(CallSiteNode* callSiteObj) {
constexpr JSOp op = JSOp::CallSiteObj;
// The first element of a call-site node is the raw-values list. Skip over it.
ListNode* raw = callSiteObj->rawNodes();
MOZ_ASSERT(raw->isKind(ParseNodeKind::ArrayExpr));
ParseNode* head = callSiteObj->head()->pn_next;
uint32_t count = callSiteObj->count() - 1;
MOZ_ASSERT(count == raw->count());
ObjLiteralWriter writer;
writer.beginCallSiteObj(op);
writer.beginDenseArrayElements();
// Write elements of the two arrays: the 'cooked' values followed by the
// 'raw' values.
MOZ_RELEASE_ASSERT(count < UINT32_MAX / 2,
"Number of elements for both arrays must fit in uint32_t");
if (!emitCallSiteObjectArray(writer, callSiteObj, head, count)) {
return false;
}
if (!emitCallSiteObjectArray(writer, raw, raw->head(), count)) {
return false;
}
GCThingIndex cookedIndex;
if (!addObjLiteralData(writer, &cookedIndex)) {
return false;
}
MOZ_ASSERT(sc->hasCallSiteObj());
return emitInternedObjectOp(cookedIndex, op);
}
bool BytecodeEmitter::emitCatch(BinaryNode* catchClause) {
// We must be nested under a try-finally statement.
MOZ_ASSERT(innermostNestableControl->is<TryFinallyControl>());
ParseNode* param = catchClause->left();
if (!param) {
// Catch parameter was omitted; just discard the exception.
if (!emit1(JSOp::Pop)) {
return false;
}
} else {
switch (param->getKind()) {
case ParseNodeKind::ArrayExpr:
case ParseNodeKind::ObjectExpr:
if (!emitDestructuringOps(¶m->as<ListNode>(),
DestructuringFlavor::Declaration)) {
return false;
}
if (!emit1(JSOp::Pop)) {
return false;
}
break;
case ParseNodeKind::Name:
if (!emitLexicalInitialization(¶m->as<NameNode>())) {
return false;
}
if (!emit1(JSOp::Pop)) {
return false;
}
break;
default:
MOZ_ASSERT(0);
}
}
/* Emit the catch body. */
return emitTree(catchClause->right());
}
// Using MOZ_NEVER_INLINE in here is a workaround for llvm.org/pr14047. See the
// comment on EmitSwitch.
MOZ_NEVER_INLINE bool BytecodeEmitter::emitTry(TryNode* tryNode) {
LexicalScopeNode* catchScope = tryNode->catchScope();
ParseNode* finallyNode = tryNode->finallyBlock();
TryEmitter::Kind kind;
if (catchScope) {
if (finallyNode) {
kind = TryEmitter::Kind::TryCatchFinally;
} else {
kind = TryEmitter::Kind::TryCatch;
}
} else {
MOZ_ASSERT(finallyNode);
kind = TryEmitter::Kind::TryFinally;
}
TryEmitter tryCatch(this, kind, TryEmitter::ControlKind::Syntactic);
if (!tryCatch.emitTry()) {
return false;
}
if (!emitTree(tryNode->body())) {
return false;
}
// If this try has a catch block, emit it.
if (catchScope) {
// The emitted code for a catch block looks like:
//
// [pushlexicalenv] only if any local aliased
// exception
// setlocal 0; pop assign or possibly destructure exception
// < catch block contents >
// debugleaveblock
// [poplexicalenv] only if any local aliased
// if there is a finally block:
// goto <finally>
// [jump target for returning from finally]
// goto <after finally>
if (!tryCatch.emitCatch()) {
return false;
}
// Emit the lexical scope and catch body.
if (!emitTree(catchScope)) {
return false;
}
}
// Emit the finally handler, if there is one.
if (finallyNode) {
if (!tryCatch.emitFinally(Some(finallyNode->pn_pos.begin))) {
return false;
}
if (!emitTree(finallyNode)) {
return false;
}
}
if (!tryCatch.emitEnd()) {
return false;
}
return true;
}
[[nodiscard]] bool BytecodeEmitter::emitJumpToFinally(JumpList* jump,
uint32_t idx) {
// Push the continuation index.
if (!emitNumberOp(idx)) {
return false;
}
// Push |exception_stack|.
if (!emit1(JSOp::Null)) {
return false;
}
// Push |throwing|.
if (!emit1(JSOp::False)) {
return false;
}
// Jump to the finally block.
if (!emitJumpNoFallthrough(JSOp::Goto, jump)) {
return false;
}
return true;
}
bool BytecodeEmitter::emitIf(TernaryNode* ifNode) {
IfEmitter ifThenElse(this);
if (!ifThenElse.emitIf(Some(ifNode->kid1()->pn_pos.begin))) {
return false;
}
if_again:
ParseNode* testNode = ifNode->kid1();
auto conditionKind = IfEmitter::ConditionKind::Positive;
if (testNode->isKind(ParseNodeKind::NotExpr)) {
testNode = testNode->as<UnaryNode>().kid();
conditionKind = IfEmitter::ConditionKind::Negative;
}
if (!markStepBreakpoint()) {
return false;
}
// Emit code for the condition before pushing stmtInfo.
// NOTE: NotExpr of testNode may be unwrapped, and in that case the negation
// is handled by conditionKind.
if (!emitTree(testNode)) {
return false;
}
ParseNode* elseNode = ifNode->kid3();
if (elseNode) {
if (!ifThenElse.emitThenElse(conditionKind)) {
return false;
}
} else {
if (!ifThenElse.emitThen(conditionKind)) {
return false;
}
}
/* Emit code for the then part. */
if (!emitTree(ifNode->kid2())) {
return false;
}
if (elseNode) {
if (elseNode->isKind(ParseNodeKind::IfStmt)) {
ifNode = &elseNode->as<TernaryNode>();
if (!ifThenElse.emitElseIf(Some(ifNode->kid1()->pn_pos.begin))) {
return false;
}
goto if_again;
}
if (!ifThenElse.emitElse()) {
return false;
}
/* Emit code for the else part. */
if (!emitTree(elseNode)) {
return false;
}
}
if (!ifThenElse.emitEnd()) {
return false;
}
return true;
}
bool BytecodeEmitter::emitHoistedFunctionsInList(ListNode* stmtList) {
MOZ_ASSERT(stmtList->hasTopLevelFunctionDeclarations());
// We can call this multiple times for sloppy eval scopes.
if (stmtList->emittedTopLevelFunctionDeclarations()) {
return true;
}
stmtList->setEmittedTopLevelFunctionDeclarations();
for (ParseNode* stmt : stmtList->contents()) {
ParseNode* maybeFun = stmt;
if (!sc->strict()) {
while (maybeFun->isKind(ParseNodeKind::LabelStmt)) {
maybeFun = maybeFun->as<LabeledStatement>().statement();
}
}
if (maybeFun->is<FunctionNode>() &&
maybeFun->as<FunctionNode>().functionIsHoisted()) {
if (!emitTree(maybeFun)) {
return false;
}
}
}
return true;
}
bool BytecodeEmitter::emitLexicalScopeBody(
ParseNode* body, EmitLineNumberNote emitLineNote /* = EMIT_LINENOTE */) {
if (body->isKind(ParseNodeKind::StatementList) &&
body->as<ListNode>().hasTopLevelFunctionDeclarations()) {
// This block contains function statements whose definitions are
// hoisted to the top of the block. Emit these as a separate pass
// before the rest of the block.
if (!emitHoistedFunctionsInList(&body->as<ListNode>())) {
return false;
}
}
// Line notes were updated by emitLexicalScope or emitScript.
return emitTree(body, ValueUsage::WantValue, emitLineNote);
}
// Using MOZ_NEVER_INLINE in here is a workaround for llvm.org/pr14047. See
// the comment on emitSwitch.
MOZ_NEVER_INLINE bool BytecodeEmitter::emitLexicalScope(
LexicalScopeNode* lexicalScope) {
LexicalScopeEmitter lse(this);
ParseNode* body = lexicalScope->scopeBody();
if (lexicalScope->isEmptyScope()) {
if (!lse.emitEmptyScope()) {
return false;
}
if (!emitLexicalScopeBody(body)) {
return false;
}
if (!lse.emitEnd()) {
return false;
}
return true;
}
// We are about to emit some bytecode for what the spec calls "declaration
// instantiation". Assign these instructions to the opening `{` of the
// block. (Using the location of each declaration we're instantiating is
// too weird when stepping in the debugger.)
if (!ParseNodeRequiresSpecialLineNumberNotes(body)) {
if (!updateSourceCoordNotes(lexicalScope->pn_pos.begin)) {
return false;
}
}
ScopeKind kind;
if (body->isKind(ParseNodeKind::Catch)) {
BinaryNode* catchNode = &body->as<BinaryNode>();
kind =
(!catchNode->left() || catchNode->left()->isKind(ParseNodeKind::Name))
? ScopeKind::SimpleCatch
: ScopeKind::Catch;
} else {
kind = lexicalScope->kind();
}
if (!lse.emitScope(kind, lexicalScope->scopeBindings())) {
return false;
}
if (body->isKind(ParseNodeKind::ForStmt)) {
// for loops need to emit JSOp::FreshenLexicalEnv/JSOp::RecreateLexicalEnv
// if there are lexical declarations in the head. Signal this by passing a
// non-nullptr lexical scope.
if (!emitFor(&body->as<ForNode>(), &lse.emitterScope())) {
return false;
}
} else {
if (!emitLexicalScopeBody(body, SUPPRESS_LINENOTE)) {
return false;
}
}
if (!lse.emitEnd()) {
return false;
}
return true;
}
bool BytecodeEmitter::emitWith(BinaryNode* withNode) {
// Ensure that the column of the 'with' is set properly.
if (!updateSourceCoordNotes(withNode->left()->pn_pos.begin)) {
return false;
}
if (!markStepBreakpoint()) {
return false;
}
if (!emitTree(withNode->left())) {
return false;
}
EmitterScope emitterScope(this);
if (!emitterScope.enterWith(this)) {
return false;
}
if (!emitTree(withNode->right())) {
return false;
}
return emitterScope.leave(this);
}
bool BytecodeEmitter::emitCopyDataProperties(CopyOption option) {
DebugOnly<int32_t> depth = bytecodeSection().stackDepth();
uint32_t argc;
if (option == CopyOption::Filtered) {
MOZ_ASSERT(depth > 2);
// [stack] TARGET SOURCE SET
argc = 3;
if (!emitAtomOp(JSOp::GetIntrinsic,
TaggedParserAtomIndex::WellKnown::CopyDataProperties())) {
// [stack] TARGET SOURCE SET COPYDATAPROPERTIES
return false;
}
} else {
MOZ_ASSERT(depth > 1);
// [stack] TARGET SOURCE
argc = 2;
if (!emitAtomOp(
JSOp::GetIntrinsic,
TaggedParserAtomIndex::WellKnown::CopyDataPropertiesUnfiltered())) {
// [stack] TARGET SOURCE COPYDATAPROPERTIES
return false;
}
}
if (!emit1(JSOp::Undefined)) {
// [stack] TARGET SOURCE SET? COPYDATAPROPERTIES
// UNDEFINED
return false;
}
if (!emit2(JSOp::Pick, argc + 1)) {
// [stack] SOURCE SET? COPYDATAPROPERTIES UNDEFINED
// TARGET
return false;
}
if (!emit2(JSOp::Pick, argc + 1)) {
// [stack] SET? COPYDATAPROPERTIES UNDEFINED TARGET
// SOURCE
return false;
}
if (option == CopyOption::Filtered) {
if (!emit2(JSOp::Pick, argc + 1)) {
// [stack] COPYDATAPROPERTIES UNDEFINED TARGET SOURCE SET
return false;
}
}
// Callee is always self-hosted instrinsic, and cannot be content function.
if (!emitCall(JSOp::CallIgnoresRv, argc)) {
// [stack] IGNORED
return false;
}
if (!emit1(JSOp::Pop)) {
// [stack]
return false;
}
MOZ_ASSERT(depth - int(argc) == bytecodeSection().stackDepth());
return true;
}
bool BytecodeEmitter::emitBigIntOp(BigIntLiteral* bigint) {
GCThingIndex index;
if (!perScriptData().gcThingList().append(bigint, &index)) {
return false;
}
return emitGCIndexOp(JSOp::BigInt, index);
}
bool BytecodeEmitter::emitIterable(ParseNode* value,
SelfHostedIter selfHostedIter,
IteratorKind iterKind) {
MOZ_ASSERT(getSelfHostedIterFor(value) == selfHostedIter);
if (!emitTree(value)) {
// [stack] ITERABLE
return false;
}
switch (selfHostedIter) {
case SelfHostedIter::Deny:
case SelfHostedIter::AllowContent:
// [stack] ITERABLE
return true;
case SelfHostedIter::AllowContentWith: {
// This is the following case:
//
// for (const nextValue of allowContentIterWith(items, usingIterator)) {
//
// `items` is emitted by `emitTree(value)` above, and the result is on the
// stack as ITERABLE.
// `usingIterator` is the value of `items[Symbol.iterator]`, that's
// already retrieved.
ListNode* argsList = value->as<CallNode>().args();
MOZ_ASSERT_IF(iterKind == IteratorKind::Sync, argsList->count() == 2);
MOZ_ASSERT_IF(iterKind == IteratorKind::Async, argsList->count() == 3);
if (!emitTree(argsList->head()->pn_next)) {
// [stack] ITERABLE ITERFN
return false;
}
// Async iterator has two possible iterators: An async iterator and a sync
// iterator.
if (iterKind == IteratorKind::Async) {
if (!emitTree(argsList->head()->pn_next->pn_next)) {
// [stack] ITERABLE ASYNC_ITERFN SYNC_ITERFN
return false;
}
}
// [stack] ITERABLE ASYNC_ITERFN? SYNC_ITERFN
return true;
}
case SelfHostedIter::AllowContentWithNext: {
// This is the following case:
//
// for (const nextValue of allowContentIterWithNext(iterator, next)) {
//
// `iterator` is emitted by `emitTree(value)` above, and the result is on
// the stack as ITER.
// `next` is the value of `iterator.next`, that's already retrieved.
ListNode* argsList = value->as<CallNode>().args();
MOZ_ASSERT(argsList->count() == 2);
if (!emitTree(argsList->head()->pn_next)) {
// [stack] ITER NEXT
return false;
}
if (!emit1(JSOp::Swap)) {
// [stack] NEXT ITER
return false;
}
// [stack] NEXT ITER
return true;
}
}
MOZ_CRASH("invalid self-hosted iteration kind");
}
bool BytecodeEmitter::emitIterator(SelfHostedIter selfHostedIter) {
MOZ_ASSERT(selfHostedIter != SelfHostedIter::Deny ||
emitterMode != BytecodeEmitter::SelfHosting,
"[Symbol.iterator]() call is prohibited in self-hosted code "
"because it can run user-modifiable iteration code");
if (selfHostedIter == SelfHostedIter::AllowContentWithNext) {
// [stack] NEXT ITER
// Nothing to do, stack already contains the iterator and its `next` method.
return true;
}
if (selfHostedIter != SelfHostedIter::AllowContentWith) {
// [stack] OBJ
// Convert iterable to iterator.
if (!emit1(JSOp::Dup)) {
// [stack] OBJ OBJ
return false;
}
if (!emit2(JSOp::Symbol, uint8_t(JS::SymbolCode::iterator))) {
// [stack] OBJ OBJ @@ITERATOR
return false;
}
if (!emitElemOpBase(JSOp::GetElem)) {
// [stack] OBJ ITERFN
return false;
}
}
if (!emit1(JSOp::Swap)) {
// [stack] ITERFN OBJ
return false;
}
if (!emitCall(getIterCallOp(JSOp::CallIter, selfHostedIter), 0)) {
// [stack] ITER
return false;
}
if (!emitCheckIsObj(CheckIsObjectKind::GetIterator)) {
// [stack] ITER
return false;
}
if (!emit1(JSOp::Dup)) {
// [stack] ITER ITER
return false;
}
if (!emitAtomOp(JSOp::GetProp, TaggedParserAtomIndex::WellKnown::next())) {
// [stack] ITER NEXT
return false;
}
if (!emit1(JSOp::Swap)) {
// [stack] NEXT ITER
return false;
}
return true;
}
bool BytecodeEmitter::emitAsyncIterator(SelfHostedIter selfHostedIter) {
MOZ_ASSERT(selfHostedIter != SelfHostedIter::AllowContentWithNext);
MOZ_ASSERT(selfHostedIter != SelfHostedIter::Deny ||
emitterMode != BytecodeEmitter::SelfHosting,
"[Symbol.asyncIterator]() call is prohibited in self-hosted code "
"because it can run user-modifiable iteration code");
if (selfHostedIter != SelfHostedIter::AllowContentWith) {
// [stack] OBJ
// Convert iterable to iterator.
if (!emit1(JSOp::Dup)) {
// [stack] OBJ OBJ
return false;
}
if (!emit2(JSOp::Symbol, uint8_t(JS::SymbolCode::asyncIterator))) {
// [stack] OBJ OBJ @@ASYNCITERATOR
return false;
}
if (!emitElemOpBase(JSOp::GetElem)) {
// [stack] OBJ ASYNC_ITERFN
return false;
}
} else {
// [stack] OBJ ASYNC_ITERFN SYNC_ITERFN
if (!emitElemOpBase(JSOp::Swap)) {
// [stack] OBJ SYNC_ITERFN ASYNC_ITERFN
return false;
}
}
InternalIfEmitter ifAsyncIterIsUndefined(this);
if (!emit1(JSOp::IsNullOrUndefined)) {
// [stack] OBJ SYNC_ITERFN? ASYNC_ITERFN NULL-OR-UNDEF
return false;
}
if (!ifAsyncIterIsUndefined.emitThenElse()) {
// [stack] OBJ SYNC_ITERFN? ASYNC_ITERFN
return false;
}
if (!emit1(JSOp::Pop)) {
// [stack] OBJ SYNC_ITERFN?
return false;
}
if (selfHostedIter != SelfHostedIter::AllowContentWith) {
if (!emit1(JSOp::Dup)) {
// [stack] OBJ OBJ
return false;
}
if (!emit2(JSOp::Symbol, uint8_t(JS::SymbolCode::iterator))) {
// [stack] OBJ OBJ @@ITERATOR
return false;
}
if (!emitElemOpBase(JSOp::GetElem)) {
// [stack] OBJ SYNC_ITERFN
return false;
}
} else {
// [stack] OBJ SYNC_ITERFN
}
if (!emit1(JSOp::Swap)) {
// [stack] SYNC_ITERFN OBJ
return false;
}
if (!emitCall(getIterCallOp(JSOp::CallIter, selfHostedIter), 0)) {
// [stack] ITER
return false;
}
if (!emitCheckIsObj(CheckIsObjectKind::GetIterator)) {
// [stack] ITER
return false;
}
if (!emit1(JSOp::Dup)) {
// [stack] ITER ITER
return false;
}
if (!emitAtomOp(JSOp::GetProp, TaggedParserAtomIndex::WellKnown::next())) {
// [stack] ITER SYNCNEXT
return false;
}
if (!emit1(JSOp::ToAsyncIter)) {
// [stack] ITER
return false;
}
if (!ifAsyncIterIsUndefined.emitElse()) {
// [stack] OBJ SYNC_ITERFN? ASYNC_ITERFN
return false;
}
if (selfHostedIter == SelfHostedIter::AllowContentWith) {
if (!emit1(JSOp::Swap)) {
// [stack] OBJ ASYNC_ITERFN SYNC_ITERFN
return false;
}
if (!emit1(JSOp::Pop)) {
// [stack] OBJ ASYNC_ITERFN
return false;
}
}
if (!emit1(JSOp::Swap)) {
// [stack] ASYNC_ITERFN OBJ
return false;
}
if (!emitCall(getIterCallOp(JSOp::CallIter, selfHostedIter), 0)) {
// [stack] ITER
return false;
}
if (!emitCheckIsObj(CheckIsObjectKind::GetAsyncIterator)) {
// [stack] ITER
return false;
}
if (!ifAsyncIterIsUndefined.emitEnd()) {
// [stack] ITER
return false;
}
if (!emit1(JSOp::Dup)) {
// [stack] ITER ITER
return false;
}
if (!emitAtomOp(JSOp::GetProp, TaggedParserAtomIndex::WellKnown::next())) {
// [stack] ITER NEXT
return false;
}
if (!emit1(JSOp::Swap)) {
// [stack] NEXT ITER
return false;
}
return true;
}
bool BytecodeEmitter::emitSpread(SelfHostedIter selfHostedIter) {
// [stack] NEXT ITER ARR I
return emitSpread(selfHostedIter, 2, JSOp::InitElemInc);
// [stack] ARR FINAL_INDEX
}
bool BytecodeEmitter::emitSpread(SelfHostedIter selfHostedIter,
int spreadeeStackItems, JSOp storeElementOp) {
LoopControl loopInfo(this, StatementKind::Spread);
// In the [stack] annotations, (spreadee) can be "ARR I" (when spreading
// into an array or into call parameters, or "TUPLE" (when spreading into a
// tuple)
if (!loopInfo.emitLoopHead(this, Nothing())) {
// [stack] NEXT ITER (spreadee)
return false;
}
{
#ifdef DEBUG
auto loopDepth = bytecodeSection().stackDepth();
#endif
// Spread operations can't contain |continue|, so don't bother setting loop
// and enclosing "update" offsets, as we do with for-loops.
if (!emitDupAt(spreadeeStackItems + 1, 2)) {
// [stack] NEXT ITER (spreadee) NEXT ITER
return false;
}
if (!emitIteratorNext(Nothing(), IteratorKind::Sync, selfHostedIter)) {
// [stack] NEXT ITER (spreadee) RESULT
return false;
}
if (!emit1(JSOp::Dup)) {
// [stack] NEXT ITER (spreadee) RESULT RESULT
return false;
}
if (!emitAtomOp(JSOp::GetProp, TaggedParserAtomIndex::WellKnown::done())) {
// [stack] NEXT ITER (spreadee) RESULT DONE
return false;
}
if (!emitJump(JSOp::JumpIfTrue, &loopInfo.breaks)) {
// [stack] NEXT ITER (spreadee) RESULT
return false;
}
// Emit code to assign result.value to the iteration variable.
if (!emitAtomOp(JSOp::GetProp, TaggedParserAtomIndex::WellKnown::value())) {
// [stack] NEXT ITER (spreadee) VALUE
return false;
}
if (!emit1(storeElementOp)) {
// [stack] NEXT ITER (spreadee)
return false;
}
if (!loopInfo.emitLoopEnd(this, JSOp::Goto, TryNoteKind::ForOf)) {
// [stack] NEXT ITER (spreadee)
return false;
}
MOZ_ASSERT(bytecodeSection().stackDepth() == loopDepth);
}
// When we leave the loop body and jump to this point, the result value is
// still on the stack. Account for that by updating the stack depth
// manually.
bytecodeSection().setStackDepth(bytecodeSection().stackDepth() + 1);
// No continues should occur in spreads.
MOZ_ASSERT(!loopInfo.continues.offset.valid());
if (!emit2(JSOp::Pick, spreadeeStackItems + 2)) {
// [stack] ITER (spreadee) RESULT NEXT
return false;
}
if (!emit2(JSOp::Pick, spreadeeStackItems + 2)) {
// [stack] (spreadee) RESULT NEXT ITER
return false;
}
return emitPopN(3);
// [stack] (spreadee)
}
bool BytecodeEmitter::emitInitializeForInOrOfTarget(TernaryNode* forHead) {
MOZ_ASSERT(forHead->isKind(ParseNodeKind::ForIn) ||
forHead->isKind(ParseNodeKind::ForOf));
MOZ_ASSERT(bytecodeSection().stackDepth() >= 1,
"must have a per-iteration value for initializing");
ParseNode* target = forHead->kid1();
MOZ_ASSERT(!forHead->kid2());
// If the for-in/of loop didn't have a variable declaration, per-loop
// initialization is just assigning the iteration value to a target
// expression.
if (!target->is<DeclarationListNode>()) {
return emitAssignmentOrInit(ParseNodeKind::AssignExpr, target, nullptr);
// [stack] ... ITERVAL
}
// Otherwise, per-loop initialization is (possibly) declaration
// initialization. If the declaration is a lexical declaration, it must be
// initialized. If the declaration is a variable declaration, an
// assignment to that name (which does *not* necessarily assign to the
// variable!) must be generated.
auto* declarationList = &target->as<DeclarationListNode>();
if (!updateSourceCoordNotes(declarationList->pn_pos.begin)) {
return false;
}
target = declarationList->singleBinding();
NameNode* nameNode = nullptr;
if (target->isKind(ParseNodeKind::Name)) {
nameNode = &target->as<NameNode>();
} else if (target->isKind(ParseNodeKind::AssignExpr)) {
BinaryNode* assignNode = &target->as<BinaryNode>();
if (assignNode->left()->is<NameNode>()) {
nameNode = &assignNode->left()->as<NameNode>();
}
}
if (nameNode) {
auto nameAtom = nameNode->name();
NameOpEmitter noe(this, nameAtom, NameOpEmitter::Kind::Initialize);
if (!noe.prepareForRhs()) {
return false;
}
if (noe.emittedBindOp()) {
// Per-iteration initialization in for-in/of loops computes the
// iteration value *before* initializing. Thus the initializing
// value may be buried under a bind-specific value on the stack.
// Swap it to the top of the stack.
MOZ_ASSERT(bytecodeSection().stackDepth() >= 2);
if (!emit1(JSOp::Swap)) {
return false;
}
} else {
// In cases of emitting a frame slot or environment slot,
// nothing needs be done.
MOZ_ASSERT(bytecodeSection().stackDepth() >= 1);
}
if (!noe.emitAssignment()) {
return false;
}
// The caller handles removing the iteration value from the stack.
return true;
}
MOZ_ASSERT(
!target->isKind(ParseNodeKind::AssignExpr),
"for-in/of loop destructuring declarations can't have initializers");
MOZ_ASSERT(target->isKind(ParseNodeKind::ArrayExpr) ||
target->isKind(ParseNodeKind::ObjectExpr));
return emitDestructuringOps(&target->as<ListNode>(),
DestructuringFlavor::Declaration);
}
bool BytecodeEmitter::emitForOf(ForNode* forOfLoop,
const EmitterScope* headLexicalEmitterScope) {
MOZ_ASSERT(forOfLoop->isKind(ParseNodeKind::ForStmt));
TernaryNode* forOfHead = forOfLoop->head();
MOZ_ASSERT(forOfHead->isKind(ParseNodeKind::ForOf));
unsigned iflags = forOfLoop->iflags();
IteratorKind iterKind =
(iflags & JSITER_FORAWAITOF) ? IteratorKind::Async : IteratorKind::Sync;
MOZ_ASSERT_IF(iterKind == IteratorKind::Async, sc->isSuspendableContext());
MOZ_ASSERT_IF(iterKind == IteratorKind::Async,
sc->asSuspendableContext()->isAsync());
ParseNode* forHeadExpr = forOfHead->kid3();
// Certain builtins (e.g. Array.from) are implemented in self-hosting
// as for-of loops.
auto selfHostedIter = getSelfHostedIterFor(forHeadExpr);
ForOfEmitter forOf(this, headLexicalEmitterScope, selfHostedIter, iterKind);
if (!forOf.emitIterated()) {
// [stack]
return false;
}
if (!updateSourceCoordNotes(forHeadExpr->pn_pos.begin)) {
return false;
}
if (!markStepBreakpoint()) {
return false;
}
if (!emitIterable(forHeadExpr, selfHostedIter, iterKind)) {
// [stack] ITERABLE
return false;
}
if (headLexicalEmitterScope) {
DebugOnly<ParseNode*> forOfTarget = forOfHead->kid1();
MOZ_ASSERT(forOfTarget->isKind(ParseNodeKind::LetDecl) ||
forOfTarget->isKind(ParseNodeKind::ConstDecl));
}
if (!forOf.emitInitialize(forOfHead->pn_pos.begin)) {
// [stack] NEXT ITER VALUE
return false;
}
if (!emitInitializeForInOrOfTarget(forOfHead)) {
// [stack] NEXT ITER VALUE
return false;
}
if (!forOf.emitBody()) {
// [stack] NEXT ITER UNDEF
return false;
}
// Perform the loop body.
ParseNode* forBody = forOfLoop->body();
if (!emitTree(forBody)) {
// [stack] NEXT ITER UNDEF
return false;
}
if (!forOf.emitEnd(forHeadExpr->pn_pos.begin)) {
// [stack]
return false;
}
return true;
}
bool BytecodeEmitter::emitForIn(ForNode* forInLoop,
const EmitterScope* headLexicalEmitterScope) {
TernaryNode* forInHead = forInLoop->head();
MOZ_ASSERT(forInHead->isKind(ParseNodeKind::ForIn));
ForInEmitter forIn(this, headLexicalEmitterScope);
// Annex B: Evaluate the var-initializer expression if present.
// |for (var i = initializer in expr) { ... }|
ParseNode* forInTarget = forInHead->kid1();
if (forInTarget->is<DeclarationListNode>()) {
auto* declarationList = &forInTarget->as<DeclarationListNode>();
ParseNode* decl = declarationList->singleBinding();
if (decl->isKind(ParseNodeKind::AssignExpr)) {
BinaryNode* assignNode = &decl->as<BinaryNode>();
if (assignNode->left()->is<NameNode>()) {
NameNode* nameNode = &assignNode->left()->as<NameNode>();
ParseNode* initializer = assignNode->right();
MOZ_ASSERT(
forInTarget->isKind(ParseNodeKind::VarStmt),
"for-in initializers are only permitted for |var| declarations");
if (!updateSourceCoordNotes(decl->pn_pos.begin)) {
return false;
}
auto nameAtom = nameNode->name();
NameOpEmitter noe(this, nameAtom, NameOpEmitter::Kind::Initialize);
if (!noe.prepareForRhs()) {
return false;
}
if (!emitInitializer(initializer, nameNode)) {
return false;
}
if (!noe.emitAssignment()) {
return false;
}
// Pop the initializer.
if (!emit1(JSOp::Pop)) {
return false;
}
}
}
}
if (!forIn.emitIterated()) {
// [stack]
return false;
}
// Evaluate the expression being iterated.
ParseNode* expr = forInHead->kid3();
if (!updateSourceCoordNotes(expr->pn_pos.begin)) {
return false;
}
if (!markStepBreakpoint()) {
return false;
}
if (!emitTree(expr)) {
// [stack] EXPR
return false;
}
MOZ_ASSERT(forInLoop->iflags() == 0);
MOZ_ASSERT_IF(headLexicalEmitterScope,
forInTarget->isKind(ParseNodeKind::LetDecl) ||
forInTarget->isKind(ParseNodeKind::ConstDecl));
if (!forIn.emitInitialize()) {
// [stack] ITER ITERVAL
return false;
}
if (!emitInitializeForInOrOfTarget(forInHead)) {
// [stack] ITER ITERVAL
return false;
}
if (!forIn.emitBody()) {
// [stack] ITER ITERVAL
return false;
}
// Perform the loop body.
ParseNode* forBody = forInLoop->body();
if (!emitTree(forBody)) {
// [stack] ITER ITERVAL
return false;
}
if (!forIn.emitEnd(forInHead->pn_pos.begin)) {
// [stack]
return false;
}
return true;
}
/* C-style `for (init; cond; update) ...` loop. */
bool BytecodeEmitter::emitCStyleFor(
ForNode* forNode, const EmitterScope* headLexicalEmitterScope) {
TernaryNode* forHead = forNode->head();
ParseNode* forBody = forNode->body();
ParseNode* init = forHead->kid1();
ParseNode* cond = forHead->kid2();
ParseNode* update = forHead->kid3();
bool isLet = init && init->isKind(ParseNodeKind::LetDecl);
CForEmitter cfor(this, isLet ? headLexicalEmitterScope : nullptr);
if (!cfor.emitInit(init ? Some(init->pn_pos.begin) : Nothing())) {
// [stack]
return false;
}
// If the head of this for-loop declared any lexical variables, the parser
// wrapped this ParseNodeKind::For node in a ParseNodeKind::LexicalScope
// representing the implicit scope of those variables. By the time we get
// here, we have already entered that scope. So far, so good.
if (init) {
// Emit the `init` clause, whether it's an expression or a variable
// declaration. (The loop variables were hoisted into an enclosing
// scope, but we still need to emit code for the initializers.)
if (init->is<DeclarationListNode>()) {
MOZ_ASSERT(!init->as<DeclarationListNode>().empty());
if (!emitTree(init)) {
// [stack]
return false;
}
} else {
if (!updateSourceCoordNotes(init->pn_pos.begin)) {
return false;
}
if (!markStepBreakpoint()) {
return false;
}
// 'init' is an expression, not a declaration. emitTree left its
// value on the stack.
if (!emitTree(init, ValueUsage::IgnoreValue)) {
// [stack] VAL
return false;
}
if (!emit1(JSOp::Pop)) {
// [stack]
return false;
}
}
}
if (!cfor.emitCond(cond ? Some(cond->pn_pos.begin) : Nothing())) {
// [stack]
return false;
}
if (cond) {
if (!updateSourceCoordNotes(cond->pn_pos.begin)) {
return false;
}
if (!markStepBreakpoint()) {
return false;
}
if (!emitTree(cond)) {
// [stack] VAL
return false;
}
}
if (!cfor.emitBody(cond ? CForEmitter::Cond::Present
: CForEmitter::Cond::Missing)) {
// [stack]
return false;
}
if (!emitTree(forBody)) {
// [stack]
return false;
}
if (!cfor.emitUpdate(
update ? CForEmitter::Update::Present : CForEmitter::Update::Missing,
update ? Some(update->pn_pos.begin) : Nothing())) {
// [stack]
return false;
}
// Check for update code to do before the condition (if any).
if (update) {
if (!updateSourceCoordNotes(update->pn_pos.begin)) {
return false;
}
if (!markStepBreakpoint()) {
return false;
}
if (!emitTree(update, ValueUsage::IgnoreValue)) {
// [stack] VAL
return false;
}
}
if (!cfor.emitEnd(forNode->pn_pos.begin)) {
// [stack]
return false;
}
return true;
}
bool BytecodeEmitter::emitFor(ForNode* forNode,
const EmitterScope* headLexicalEmitterScope) {
if (forNode->head()->isKind(ParseNodeKind::ForHead)) {
return emitCStyleFor(forNode, headLexicalEmitterScope);
}
if (!updateLineNumberNotes(forNode->pn_pos.begin)) {
return false;
}
if (forNode->head()->isKind(ParseNodeKind::ForIn)) {
return emitForIn(forNode, headLexicalEmitterScope);
}
MOZ_ASSERT(forNode->head()->isKind(ParseNodeKind::ForOf));
return emitForOf(forNode, headLexicalEmitterScope);
}
MOZ_NEVER_INLINE bool BytecodeEmitter::emitFunction(
FunctionNode* funNode, bool needsProto /* = false */) {
FunctionBox* funbox = funNode->funbox();
// [stack]
FunctionEmitter fe(this, funbox, funNode->syntaxKind(),
funNode->functionIsHoisted()
? FunctionEmitter::IsHoisted::Yes
: FunctionEmitter::IsHoisted::No);
// |wasEmittedByEnclosingScript| flag is set to true once the function has
// been emitted. Function definitions that need hoisting to the top of the
// function will be seen by emitFunction in two places.
if (funbox->wasEmittedByEnclosingScript()) {
if (!fe.emitAgain()) {
// [stack]
return false;
}
MOZ_ASSERT(funNode->functionIsHoisted());
} else if (funbox->isInterpreted()) {
if (!funbox->emitBytecode) {
return fe.emitLazy();
// [stack] FUN?
}
if (!fe.prepareForNonLazy()) {
// [stack]
return false;
}
BytecodeEmitter bce2(this, funbox);
if (!bce2.init(funNode->pn_pos)) {
return false;
}
/* We measured the max scope depth when we parsed the function. */
if (!bce2.emitFunctionScript(funNode)) {
return false;
}
if (!fe.emitNonLazyEnd()) {
// [stack] FUN?
return false;
}
} else {
if (!fe.emitAsmJSModule()) {
// [stack]
return false;
}
}
// Track the last emitted top-level self-hosted function, so that intrinsics
// can adjust attributes at parse time.
//
// NOTE: We also disallow lambda functions in the top-level body. This is done
// to simplify handling of the self-hosted stencil. Within normal function
// declarations there are no such restrictions.
if (emitterMode == EmitterMode::SelfHosting) {
if (sc->isTopLevelContext()) {
MOZ_ASSERT(!funbox->isLambda());
MOZ_ASSERT(funbox->explicitName());
prevSelfHostedTopLevelFunction = funbox;
}
}
return true;
}
bool BytecodeEmitter::emitDo(BinaryNode* doNode) {
ParseNode* bodyNode = doNode->left();
DoWhileEmitter doWhile(this);
if (!doWhile.emitBody(doNode->pn_pos.begin, getOffsetForLoop(bodyNode))) {
return false;
}
if (!emitTree(bodyNode)) {
return false;
}
if (!doWhile.emitCond()) {
return false;
}
ParseNode* condNode = doNode->right();
if (!updateSourceCoordNotes(condNode->pn_pos.begin)) {
return false;
}
if (!markStepBreakpoint()) {
return false;
}
if (!emitTree(condNode)) {
return false;
}
if (!doWhile.emitEnd()) {
return false;
}
return true;
}
bool BytecodeEmitter::emitWhile(BinaryNode* whileNode) {
ParseNode* bodyNode = whileNode->right();
WhileEmitter wh(this);
ParseNode* condNode = whileNode->left();
if (!wh.emitCond(whileNode->pn_pos.begin, getOffsetForLoop(condNode),
whileNode->pn_pos.end)) {
return false;
}
if (!updateSourceCoordNotes(condNode->pn_pos.begin)) {
return false;
}
if (!markStepBreakpoint()) {
return false;
}
if (!emitTree(condNode)) {
return false;
}
if (!wh.emitBody()) {
return false;
}
if (!emitTree(bodyNode)) {
return false;
}
if (!wh.emitEnd()) {
return false;
}
return true;
}
bool BytecodeEmitter::emitBreak(TaggedParserAtomIndex label) {
BreakableControl* target;
if (label) {
// Any statement with the matching label may be the break target.
auto hasSameLabel = [label](LabelControl* labelControl) {
return labelControl->label() == label;
};
target = findInnermostNestableControl<LabelControl>(hasSameLabel);
} else {
auto isNotLabel = [](BreakableControl* control) {
return !control->is<LabelControl>();
};
target = findInnermostNestableControl<BreakableControl>(isNotLabel);
}
return emitGoto(target, GotoKind::Break);
}
bool BytecodeEmitter::emitContinue(TaggedParserAtomIndex label) {
LoopControl* target = nullptr;
if (label) {
// Find the loop statement enclosed by the matching label.
NestableControl* control = innermostNestableControl;
while (!control->is<LabelControl>() ||
control->as<LabelControl>().label() != label) {
if (control->is<LoopControl>()) {
target = &control->as<LoopControl>();
}
control = control->enclosing();
}
} else {
target = findInnermostNestableControl<LoopControl>();
}
return emitGoto(target, GotoKind::Continue);
}
bool BytecodeEmitter::emitGetFunctionThis(NameNode* thisName) {
MOZ_ASSERT(sc->hasFunctionThisBinding());
MOZ_ASSERT(thisName->isName(TaggedParserAtomIndex::WellKnown::dot_this_()));
if (!updateLineNumberNotes(thisName->pn_pos.begin)) {
return false;
}
if (!emitGetName(TaggedParserAtomIndex::WellKnown::dot_this_())) {
// [stack] THIS
return false;
}
if (sc->needsThisTDZChecks()) {
if (!emit1(JSOp::CheckThis)) {
// [stack] THIS
return false;
}
}
return true;
}
bool BytecodeEmitter::emitGetThisForSuperBase(UnaryNode* superBase) {
MOZ_ASSERT(superBase->isKind(ParseNodeKind::SuperBase));
NameNode* nameNode = &superBase->kid()->as<NameNode>();
return emitGetFunctionThis(nameNode);
// [stack] THIS
}
bool BytecodeEmitter::emitThisLiteral(ThisLiteral* pn) {
if (ParseNode* kid = pn->kid()) {
NameNode* thisName = &kid->as<NameNode>();
return emitGetFunctionThis(thisName);
// [stack] THIS
}
if (sc->thisBinding() == ThisBinding::Module) {
return emit1(JSOp::Undefined);
// [stack] UNDEF
}
MOZ_ASSERT(sc->thisBinding() == ThisBinding::Global);
MOZ_ASSERT(outermostScope().hasNonSyntacticScopeOnChain() ==
sc->hasNonSyntacticScope());
if (sc->hasNonSyntacticScope()) {
return emit1(JSOp::NonSyntacticGlobalThis);
// [stack] THIS
}
return emit1(JSOp::GlobalThis);
// [stack] THIS
}
bool BytecodeEmitter::emitCheckDerivedClassConstructorReturn() {
MOZ_ASSERT(
lookupName(TaggedParserAtomIndex::WellKnown::dot_this_()).hasKnownSlot());
if (!emitGetName(TaggedParserAtomIndex::WellKnown::dot_this_())) {
return false;
}
if (!emit1(JSOp::CheckReturn)) {
return false;
}
if (!emit1(JSOp::SetRval)) {
return false;
}
return true;
}
bool BytecodeEmitter::emitNewTarget() {
MOZ_ASSERT(sc->allowNewTarget());
if (!emitGetName(TaggedParserAtomIndex::WellKnown::dot_newTarget_())) {
// [stack] NEW.TARGET
return false;
}
return true;
}
bool BytecodeEmitter::emitNewTarget(NewTargetNode* pn) {
MOZ_ASSERT(pn->newTargetName()->isName(
TaggedParserAtomIndex::WellKnown::dot_newTarget_()));
return emitNewTarget();
}
bool BytecodeEmitter::emitNewTarget(CallNode* pn) {
MOZ_ASSERT(pn->callOp() == JSOp::SuperCall ||
pn->callOp() == JSOp::SpreadSuperCall);
// The parser is responsible for marking the "new.target" binding as being
// implicitly used in super() calls.
return emitNewTarget();
}
bool BytecodeEmitter::emitReturn(UnaryNode* returnNode) {
if (!updateSourceCoordNotes(returnNode->pn_pos.begin)) {
return false;
}
if (!markStepBreakpoint()) {
return false;
}
/* Push a return value */
if (ParseNode* expr = returnNode->kid()) {
if (!emitTree(expr)) {
return false;
}
if (sc->asSuspendableContext()->isAsync() &&
sc->asSuspendableContext()->isGenerator()) {
if (!emitAwaitInInnermostScope()) {
return false;
}
}
} else {
/* No explicit return value provided */
if (!emit1(JSOp::Undefined)) {
return false;
}
}
// We know functionBodyEndPos is set because "return" is only
// valid in a function, and so we've passed through
// emitFunctionScript.
if (!updateSourceCoordNotes(*functionBodyEndPos)) {
return false;
}
/*
* The return value is currently on the stack. We would like to
* generate JSOp::Return, but if we have work to do before returning,
* we will instead generate JSOp::SetRval / JSOp::RetRval.
*
* We don't know whether we will need fixup code until after calling
* prepareForNonLocalJumpToOutermost, so we start by generating
* JSOp::SetRval, then mutate it to JSOp::Return in finishReturn if it
* wasn't needed.
*/
BytecodeOffset setRvalOffset = bytecodeSection().offset();
if (!emit1(JSOp::SetRval)) {
return false;
}
NonLocalExitControl nle(this, NonLocalExitKind::Return);
return nle.emitReturn(setRvalOffset);
}
bool BytecodeEmitter::finishReturn(BytecodeOffset setRvalOffset) {
// The return value is currently in rval. Depending on the current function,
// we may have to do additional work before returning:
// - Derived class constructors must check if the return value is an object.
// - Generators and async functions must do a final yield.
// - Non-async generators must return the value as an iterator result:
// { value: <rval>, done: true }
// - Non-generator async functions must resolve the function's result promise
// with the value.
//
// If we have not generated any code since the SetRval that stored the return
// value, we can also optimize the bytecode by rewriting that SetRval as a
// JSOp::Return. See |emitReturn| above.
bool isDerivedClassConstructor =
sc->isFunctionBox() && sc->asFunctionBox()->isDerivedClassConstructor();
bool needsFinalYield =
sc->isFunctionBox() && sc->asFunctionBox()->needsFinalYield();
bool isSimpleReturn =
setRvalOffset.valid() &&
setRvalOffset + BytecodeOffsetDiff(JSOpLength_SetRval) ==
bytecodeSection().offset();
if (isDerivedClassConstructor) {
MOZ_ASSERT(!needsFinalYield);
if (!emitJump(JSOp::Goto, &endOfDerivedClassConstructorBody)) {
return false;
}
return true;
}
if (needsFinalYield) {
if (!emitJump(JSOp::Goto, &finalYields)) {
return false;
}
return true;
}
if (isSimpleReturn) {
MOZ_ASSERT(JSOp(bytecodeSection().code()[setRvalOffset.value()]) ==
JSOp::SetRval);
bytecodeSection().code()[setRvalOffset.value()] = jsbytecode(JSOp::Return);
return true;
}
// Nothing special needs to be done.
return emitReturnRval();
}
bool BytecodeEmitter::emitGetDotGeneratorInScope(EmitterScope& currentScope) {
if (!sc->isFunction() && sc->isModuleContext() &&
sc->asModuleContext()->isAsync()) {
NameLocation loc = *locationOfNameBoundInScopeType<ModuleScope>(
TaggedParserAtomIndex::WellKnown::dot_generator_(), ¤tScope);
return emitGetNameAtLocation(
TaggedParserAtomIndex::WellKnown::dot_generator_(), loc);
}
NameLocation loc = *locationOfNameBoundInScopeType<FunctionScope>(
TaggedParserAtomIndex::WellKnown::dot_generator_(), ¤tScope);
return emitGetNameAtLocation(
TaggedParserAtomIndex::WellKnown::dot_generator_(), loc);
}
bool BytecodeEmitter::emitInitialYield(UnaryNode* yieldNode) {
if (!emitTree(yieldNode->kid())) {
return false;
}
if (!emitYieldOp(JSOp::InitialYield)) {
// [stack] RVAL GENERATOR RESUMEKIND
return false;
}
if (!emit1(JSOp::CheckResumeKind)) {
// [stack] RVAL
return false;
}
if (!emit1(JSOp::Pop)) {
// [stack]
return false;
}
return true;
}
bool BytecodeEmitter::emitYield(UnaryNode* yieldNode) {
MOZ_ASSERT(sc->isFunctionBox());
MOZ_ASSERT(sc->asFunctionBox()->isGenerator());
MOZ_ASSERT(yieldNode->isKind(ParseNodeKind::YieldExpr));
bool needsIteratorResult = sc->asFunctionBox()->needsIteratorResult();
if (needsIteratorResult) {
if (!emitPrepareIteratorResult()) {
// [stack] ITEROBJ
return false;
}
}
if (ParseNode* expr = yieldNode->kid()) {
if (!emitTree(expr)) {
// [stack] ITEROBJ? VAL
return false;
}
} else {
if (!emit1(JSOp::Undefined)) {
// [stack] ITEROBJ? UNDEFINED
return false;
}
}
if (sc->asSuspendableContext()->isAsync()) {
MOZ_ASSERT(!needsIteratorResult);
if (!emitAwaitInInnermostScope()) {
// [stack] RESULT
return false;
}
}
if (needsIteratorResult) {
if (!emitFinishIteratorResult(false)) {
// [stack] ITEROBJ
return false;
}
}
if (!emitGetDotGeneratorInInnermostScope()) {
// [stack] # if needsIteratorResult
// [stack] ITEROBJ .GENERATOR
// [stack] # else
// [stack] RESULT .GENERATOR
return false;
}
if (!emitYieldOp(JSOp::Yield)) {
// [stack] YIELDRESULT GENERATOR RESUMEKIND
return false;
}
if (!emit1(JSOp::CheckResumeKind)) {
// [stack] YIELDRESULT
return false;
}
return true;
}
bool BytecodeEmitter::emitAwaitInInnermostScope(UnaryNode* awaitNode) {
MOZ_ASSERT(sc->isSuspendableContext());
MOZ_ASSERT(awaitNode->isKind(ParseNodeKind::AwaitExpr));
if (!emitTree(awaitNode->kid())) {
return false;
}
return emitAwaitInInnermostScope();
}
bool BytecodeEmitter::emitAwaitInScope(EmitterScope& currentScope) {
if (!emit1(JSOp::CanSkipAwait)) {
// [stack] VALUE CANSKIP
return false;
}
if (!emit1(JSOp::MaybeExtractAwaitValue)) {
// [stack] VALUE_OR_RESOLVED CANSKIP
return false;
}
InternalIfEmitter ifCanSkip(this);
if (!ifCanSkip.emitThen(IfEmitter::ConditionKind::Negative)) {
// [stack] VALUE_OR_RESOLVED
return false;
}
if (sc->asSuspendableContext()->needsPromiseResult()) {
if (!emitGetDotGeneratorInScope(currentScope)) {
// [stack] VALUE GENERATOR
return false;
}
if (!emit1(JSOp::AsyncAwait)) {
// [stack] PROMISE
return false;
}
}
if (!emitGetDotGeneratorInScope(currentScope)) {
// [stack] VALUE|PROMISE GENERATOR
return false;
}
if (!emitYieldOp(JSOp::Await)) {
// [stack] RESOLVED GENERATOR RESUMEKIND
return false;
}
if (!emit1(JSOp::CheckResumeKind)) {
// [stack] RESOLVED
return false;
}
if (!ifCanSkip.emitEnd()) {
return false;
}
MOZ_ASSERT(ifCanSkip.popped() == 0);
return true;
}
// ES2019 draft rev 49b781ec80117b60f73327ef3054703a3111e40c
// 14.4.14 Runtime Semantics: Evaluation
// YieldExpression : yield* AssignmentExpression
bool BytecodeEmitter::emitYieldStar(ParseNode* iter) {
MOZ_ASSERT(getSelfHostedIterFor(iter) == SelfHostedIter::Deny,
"yield* is prohibited in self-hosted code because it can run "
"user-modifiable iteration code");
MOZ_ASSERT(sc->isSuspendableContext());
MOZ_ASSERT(sc->asSuspendableContext()->isGenerator());
// Step 1.
IteratorKind iterKind = sc->asSuspendableContext()->isAsync()
? IteratorKind::Async
: IteratorKind::Sync;
bool needsIteratorResult = sc->asSuspendableContext()->needsIteratorResult();
// Steps 2-5.
if (!emitTree(iter)) {
// [stack] ITERABLE
return false;
}
if (iterKind == IteratorKind::Async) {
if (!emitAsyncIterator(SelfHostedIter::Deny)) {
// [stack] NEXT ITER
return false;
}
} else {
if (!emitIterator(SelfHostedIter::Deny)) {
// [stack] NEXT ITER
return false;
}
}
// Step 6.
// Start with NormalCompletion(undefined).
if (!emit1(JSOp::Undefined)) {
// [stack] NEXT ITER RECEIVED
return false;
}
if (!emitPushResumeKind(GeneratorResumeKind::Next)) {
// [stack] NEXT ITER RECEIVED RESUMEKIND
return false;
}
const int32_t startDepth = bytecodeSection().stackDepth();
MOZ_ASSERT(startDepth >= 4);
// Step 7 is a loop.
LoopControl loopInfo(this, StatementKind::YieldStar);
if (!loopInfo.emitLoopHead(this, Nothing())) {
// [stack] NEXT ITER RECEIVED RESUMEKIND
return false;
}
// Step 7.a. Check for Normal completion.
if (!emit1(JSOp::Dup)) {
// [stack] NEXT ITER RECEIVED RESUMEKIND RESUMEKIND
return false;
}
if (!emitPushResumeKind(GeneratorResumeKind::Next)) {
// [stack] NEXT ITER RECEIVED RESUMEKIND RESUMEKIND NORMAL
return false;
}
if (!emit1(JSOp::StrictEq)) {
// [stack] NEXT ITER RECEIVED RESUMEKIND IS_NORMAL
return false;
}
InternalIfEmitter ifKind(this);
if (!ifKind.emitThenElse()) {
// [stack] NEXT ITER RECEIVED RESUMEKIND
return false;
}
{
if (!emit1(JSOp::Pop)) {
// [stack] NEXT ITER RECEIVED
return false;
}
// Step 7.a.i.
// result = iter.next(received)
if (!emit2(JSOp::Unpick, 2)) {
// [stack] RECEIVED NEXT ITER
return false;
}
if (!emit1(JSOp::Dup2)) {
// [stack] RECEIVED NEXT ITER NEXT ITER
return false;
}
if (!emit2(JSOp::Pick, 4)) {
// [stack] NEXT ITER NEXT ITER RECEIVED
return false;
}
if (!emitCall(JSOp::Call, 1, iter)) {
// [stack] NEXT ITER RESULT
return false;
}
// Step 7.a.ii.
if (iterKind == IteratorKind::Async) {
if (!emitAwaitInInnermostScope()) {
// [stack] NEXT ITER RESULT
return false;
}
}
// Step 7.a.iii.
if (!emitCheckIsObj(CheckIsObjectKind::IteratorNext)) {
// [stack] NEXT ITER RESULT
return false;
}
// Bytecode for steps 7.a.iv-vii is emitted after the ifKind if-else because
// it's shared with other branches.
}
// Step 7.b. Check for Throw completion.
if (!ifKind.emitElseIf(Nothing())) {
// [stack] NEXT ITER RECEIVED RESUMEKIND
return false;
}
if (!emit1(JSOp::Dup)) {
// [stack] NEXT ITER RECEIVED RESUMEKIND RESUMEKIND
return false;
}
if (!emitPushResumeKind(GeneratorResumeKind::Throw)) {
// [stack] NEXT ITER RECEIVED RESUMEKIND RESUMEKIND THROW
return false;
}
if (!emit1(JSOp::StrictEq)) {
// [stack] NEXT ITER RECEIVED RESUMEKIND IS_THROW
return false;
}
if (!ifKind.emitThenElse()) {
// [stack] NEXT ITER RECEIVED RESUMEKIND
return false;
}
{
if (!emit1(JSOp::Pop)) {
// [stack] NEXT ITER RECEIVED
return false;
}
// Step 7.b.i.
if (!emitDupAt(1)) {
// [stack] NEXT ITER RECEIVED ITER
return false;
}
if (!emit1(JSOp::Dup)) {
// [stack] NEXT ITER RECEIVED ITER ITER
return false;
}
if (!emitAtomOp(JSOp::GetProp,
TaggedParserAtomIndex::WellKnown::throw_())) {
// [stack] NEXT ITER RECEIVED ITER THROW
return false;
}
// Step 7.b.ii.
InternalIfEmitter ifThrowMethodIsNotDefined(this);
if (!emit1(JSOp::IsNullOrUndefined)) {
// [stack] NEXT ITER RECEIVED ITER THROW NULL-OR-UNDEF
return false;
}
if (!ifThrowMethodIsNotDefined.emitThenElse(
IfEmitter::ConditionKind::Negative)) {
// [stack] NEXT ITER RECEIVED ITER THROW
return false;
}
// Step 7.b.ii.1.
// RESULT = ITER.throw(EXCEPTION)
if (!emit1(JSOp::Swap)) {
// [stack] NEXT ITER RECEIVED THROW ITER
return false;
}
if (!emit2(JSOp::Pick, 2)) {
// [stack] NEXT ITER THROW ITER RECEIVED
return false;
}
if (!emitCall(JSOp::Call, 1, iter)) {
// [stack] NEXT ITER RESULT
return false;
}
// Step 7.b.ii.2.
if (iterKind == IteratorKind::Async) {
if (!emitAwaitInInnermostScope()) {
// [stack] NEXT ITER RESULT
return false;
}
}
// Step 7.b.ii.4.
if (!emitCheckIsObj(CheckIsObjectKind::IteratorThrow)) {
// [stack] NEXT ITER RESULT
return false;
}
// Bytecode for steps 7.b.ii.5-8 is emitted after the ifKind if-else because
// it's shared with other branches.
// Step 7.b.iii.
if (!ifThrowMethodIsNotDefined.emitElse()) {
// [stack] NEXT ITER RECEIVED ITER THROW
return false;
}
if (!emit1(JSOp::Pop)) {
// [stack] NEXT ITER RECEIVED ITER
return false;
}
// Steps 7.b.iii.1-4.
//
// If the iterator does not have a "throw" method, it calls IteratorClose
// and then throws a TypeError.
if (!emitIteratorCloseInInnermostScope(iterKind, CompletionKind::Normal)) {
// [stack] NEXT ITER RECEIVED ITER
return false;
}
// Steps 7.b.iii.5-6.
if (!emit2(JSOp::ThrowMsg, uint8_t(ThrowMsgKind::IteratorNoThrow))) {
// [stack] NEXT ITER RECEIVED ITER
// [stack] # throw
return false;
}
if (!ifThrowMethodIsNotDefined.emitEnd()) {
return false;
}
}
// Step 7.c. It must be a Return completion.
if (!ifKind.emitElse()) {
// [stack] NEXT ITER RECEIVED RESUMEKIND
return false;
}
{
if (!emit1(JSOp::Pop)) {
// [stack] NEXT ITER RECEIVED
return false;
}
// Step 7.c.i.
//
// Call iterator.return() for receiving a "forced return" completion from
// the generator.
// Step 7.c.ii.
//
// Get the "return" method.
if (!emitDupAt(1)) {
// [stack] NEXT ITER RECEIVED ITER
return false;
}
if (!emit1(JSOp::Dup)) {
// [stack] NEXT ITER RECEIVED ITER ITER
return false;
}
if (!emitAtomOp(JSOp::GetProp,
TaggedParserAtomIndex::WellKnown::return_())) {
// [stack] NEXT ITER RECEIVED ITER RET
return false;
}
// Step 7.c.iii.
//
// Do nothing if "return" is undefined or null.
InternalIfEmitter ifReturnMethodIsDefined(this);
if (!emit1(JSOp::IsNullOrUndefined)) {
// [stack] NEXT ITER RECEIVED ITER RET NULL-OR-UNDEF
return false;
}
// Step 7.c.iv.
//
// Call "return" with the argument passed to Generator.prototype.return.
if (!ifReturnMethodIsDefined.emitThenElse(
IfEmitter::ConditionKind::Negative)) {
// [stack] NEXT ITER RECEIVED ITER RET
return false;
}
if (!emit1(JSOp::Swap)) {
// [stack] NEXT ITER RECEIVED RET ITER
return false;
}
if (!emit2(JSOp::Pick, 2)) {
// [stack] NEXT ITER RET ITER RECEIVED
return false;
}
if (needsIteratorResult) {
if (!emitAtomOp(JSOp::GetProp,
TaggedParserAtomIndex::WellKnown::value())) {
// [stack] NEXT ITER RET ITER VAL
return false;
}
}
if (!emitCall(JSOp::Call, 1)) {
// [stack] NEXT ITER RESULT
return false;
}
// Step 7.c.v.
if (iterKind == IteratorKind::Async) {
if (!emitAwaitInInnermostScope()) {
// [stack] NEXT ITER RESULT
return false;
}
}
// Step 7.c.vi.
if (!emitCheckIsObj(CheckIsObjectKind::IteratorReturn)) {
// [stack] NEXT ITER RESULT
return false;
}
// Check if the returned object from iterator.return() is done. If not,
// continue yielding.
// Steps 7.c.vii-viii.
InternalIfEmitter ifReturnDone(this);
if (!emit1(JSOp::Dup)) {
// [stack] NEXT ITER RESULT RESULT
return false;
}
if (!emitAtomOp(JSOp::GetProp, TaggedParserAtomIndex::WellKnown::done())) {
// [stack] NEXT ITER RESULT DONE
return false;
}
if (!ifReturnDone.emitThenElse()) {
// [stack] NEXT ITER RESULT
return false;
}
// Step 7.c.viii.1.
if (!emitAtomOp(JSOp::GetProp, TaggedParserAtomIndex::WellKnown::value())) {
// [stack] NEXT ITER VALUE
return false;
}
if (needsIteratorResult) {
if (!emitPrepareIteratorResult()) {
// [stack] NEXT ITER VALUE RESULT
return false;
}
if (!emit1(JSOp::Swap)) {
// [stack] NEXT ITER RESULT VALUE
return false;
}
if (!emitFinishIteratorResult(true)) {
// [stack] NEXT ITER RESULT
return false;
}
}
if (!ifReturnDone.emitElse()) {
// [stack] NEXT ITER RESULT
return false;
}
// Jump to continue label for steps 7.c.ix-x.
if (!emitJump(JSOp::Goto, &loopInfo.continues)) {
// [stack] NEXT ITER RESULT
return false;
}
if (!ifReturnDone.emitEnd()) {
// [stack] NEXT ITER RESULT
return false;
}
// Step 7.c.iii.
if (!ifReturnMethodIsDefined.emitElse()) {
// [stack] NEXT ITER RECEIVED ITER RET
return false;
}
if (!emitPopN(2)) {
// [stack] NEXT ITER RECEIVED
return false;
}
if (iterKind == IteratorKind::Async) {
// Step 7.c.iii.1.
if (!emitAwaitInInnermostScope()) {
// [stack] NEXT ITER RECEIVED
return false;
}
}
if (!ifReturnMethodIsDefined.emitEnd()) {
// [stack] NEXT ITER RECEIVED
return false;
}
// Perform a "forced generator return".
//
// Step 7.c.iii.2.
// Step 7.c.viii.2.
if (!emitGetDotGeneratorInInnermostScope()) {
// [stack] NEXT ITER RESULT GENOBJ
return false;
}
if (!emitPushResumeKind(GeneratorResumeKind::Return)) {
// [stack] NEXT ITER RESULT GENOBJ RESUMEKIND
return false;
}
if (!emit1(JSOp::CheckResumeKind)) {
// [stack] NEXT ITER RESULT GENOBJ RESUMEKIND
return false;
}
}
if (!ifKind.emitEnd()) {
// [stack] NEXT ITER RESULT
return false;
}
// Shared tail for Normal/Throw completions.
//
// Steps 7.a.iv-v.
// Steps 7.b.ii.5-6.
//
// [stack] NEXT ITER RESULT
// if (result.done) break;
if (!emit1(JSOp::Dup)) {
// [stack] NEXT ITER RESULT RESULT
return false;
}
if (!emitAtomOp(JSOp::GetProp, TaggedParserAtomIndex::WellKnown::done())) {
// [stack] NEXT ITER RESULT DONE
return false;
}
if (!emitJump(JSOp::JumpIfTrue, &loopInfo.breaks)) {
// [stack] NEXT ITER RESULT
return false;
}
// Steps 7.a.vi-vii.
// Steps 7.b.ii.7-8.
// Steps 7.c.ix-x.
if (!loopInfo.emitContinueTarget(this)) {
// [stack] NEXT ITER RESULT
return false;
}
if (iterKind == IteratorKind::Async) {
if (!emitAtomOp(JSOp::GetProp, TaggedParserAtomIndex::WellKnown::value())) {
// [stack] NEXT ITER RESULT
return false;
}
}
if (!emitGetDotGeneratorInInnermostScope()) {
// [stack] NEXT ITER RESULT GENOBJ
return false;
}
if (!emitYieldOp(JSOp::Yield)) {
// [stack] NEXT ITER RVAL GENOBJ RESUMEKIND
return false;
}
if (!emit1(JSOp::Swap)) {
// [stack] NEXT ITER RVAL RESUMEKIND GENOBJ
return false;
}
if (!emit1(JSOp::Pop)) {
// [stack] NEXT ITER RVAL RESUMEKIND
return false;
}
if (!loopInfo.emitLoopEnd(this, JSOp::Goto, TryNoteKind::Loop)) {
// [stack] NEXT ITER RVAL RESUMEKIND
return false;
}
// Jumps to this point have 3 (instead of 4) values on the stack.
MOZ_ASSERT(bytecodeSection().stackDepth() == startDepth);
bytecodeSection().setStackDepth(startDepth - 1);
// [stack] NEXT ITER RESULT
// Step 7.a.v.1.
// Step 7.b.ii.6.a.
//
// result.value
if (!emit2(JSOp::Unpick, 2)) {
// [stack] RESULT NEXT ITER
return false;
}
if (!emitPopN(2)) {
// [stack] RESULT
return false;
}
if (!emitAtomOp(JSOp::GetProp, TaggedParserAtomIndex::WellKnown::value())) {
// [stack] VALUE
return false;
}
MOZ_ASSERT(bytecodeSection().stackDepth() == startDepth - 3);
return true;
}
bool BytecodeEmitter::emitStatementList(ListNode* stmtList) {
for (ParseNode* stmt : stmtList->contents()) {
if (!emitTree(stmt)) {
return false;
}
}
return true;
}
bool BytecodeEmitter::emitExpressionStatement(UnaryNode* exprStmt) {
MOZ_ASSERT(exprStmt->isKind(ParseNodeKind::ExpressionStmt));
/*
* Top-level or called-from-a-native JS_Execute/EvaluateScript,
* debugger, and eval frames may need the value of the ultimate
* expression statement as the script's result, despite the fact
* that it appears useless to the compiler.
*
* API users may also set the ReadOnlyCompileOptions::noScriptRval option when
* calling JS_Compile* to suppress JSOp::SetRval.
*/
bool wantval = false;
bool useful = false;
if (sc->isTopLevelContext()) {
useful = wantval = !sc->noScriptRval();
}
/* Don't eliminate expressions with side effects. */
ParseNode* expr = exprStmt->kid();
if (!useful) {
if (!checkSideEffects(expr, &useful)) {
return false;
}
/*
* Don't eliminate apparently useless expressions if they are labeled
* expression statements. The startOffset() test catches the case
* where we are nesting in emitTree for a labeled compound statement.
*/
if (innermostNestableControl &&
innermostNestableControl->is<LabelControl>() &&
innermostNestableControl->as<LabelControl>().startOffset() >=
bytecodeSection().offset()) {
useful = true;
}
}
if (useful) {
ValueUsage valueUsage =
wantval ? ValueUsage::WantValue : ValueUsage::IgnoreValue;
ExpressionStatementEmitter ese(this, valueUsage);
if (!ese.prepareForExpr(exprStmt->pn_pos.begin)) {
return false;
}
if (!markStepBreakpoint()) {
return false;
}
if (!emitTree(expr, valueUsage)) {
return false;
}
if (!ese.emitEnd()) {
return false;
}
}
return true;
}
bool BytecodeEmitter::emitDeleteName(UnaryNode* deleteNode) {
MOZ_ASSERT(deleteNode->isKind(ParseNodeKind::DeleteNameExpr));
NameNode* nameExpr = &deleteNode->kid()->as<NameNode>();
MOZ_ASSERT(nameExpr->isKind(ParseNodeKind::Name));
return emitAtomOp(JSOp::DelName, nameExpr->atom());
}
bool BytecodeEmitter::emitDeleteProperty(UnaryNode* deleteNode) {
MOZ_ASSERT(deleteNode->isKind(ParseNodeKind::DeletePropExpr));
PropertyAccess* propExpr = &deleteNode->kid()->as<PropertyAccess>();
PropOpEmitter poe(this, PropOpEmitter::Kind::Delete,
propExpr->as<PropertyAccess>().isSuper()
? PropOpEmitter::ObjKind::Super
: PropOpEmitter::ObjKind::Other);
if (propExpr->isSuper()) {
// The expression |delete super.foo;| has to evaluate |super.foo|,
// which could throw if |this| hasn't yet been set by a |super(...)|
// call or the super-base is not an object, before throwing a
// ReferenceError for attempting to delete a super-reference.
UnaryNode* base = &propExpr->expression().as<UnaryNode>();
if (!emitGetThisForSuperBase(base)) {
// [stack] THIS
return false;
}
} else {
if (!poe.prepareForObj()) {
return false;
}
if (!emitPropLHS(propExpr)) {
// [stack] OBJ
return false;
}
}
if (!poe.emitDelete(propExpr->key().atom())) {
// [stack] # if Super
// [stack] THIS
// [stack] # otherwise
// [stack] SUCCEEDED
return false;
}
return true;
}
bool BytecodeEmitter::emitDeleteElement(UnaryNode* deleteNode) {
MOZ_ASSERT(deleteNode->isKind(ParseNodeKind::DeleteElemExpr));
PropertyByValue* elemExpr = &deleteNode->kid()->as<PropertyByValue>();
bool isSuper = elemExpr->isSuper();
DebugOnly<bool> isPrivate =
elemExpr->key().isKind(ParseNodeKind::PrivateName);
MOZ_ASSERT(!isPrivate);
ElemOpEmitter eoe(
this, ElemOpEmitter::Kind::Delete,
isSuper ? ElemOpEmitter::ObjKind::Super : ElemOpEmitter::ObjKind::Other);
if (isSuper) {
// The expression |delete super[foo];| has to evaluate |super[foo]|,
// which could throw if |this| hasn't yet been set by a |super(...)|
// call, or trigger side-effects when evaluating ToPropertyKey(foo),
// or also throw when the super-base is not an object, before throwing
// a ReferenceError for attempting to delete a super-reference.
if (!eoe.prepareForObj()) {
// [stack]
return false;
}
UnaryNode* base = &elemExpr->expression().as<UnaryNode>();
if (!emitGetThisForSuperBase(base)) {
// [stack] THIS
return false;
}
if (!eoe.prepareForKey()) {
// [stack] THIS
return false;
}
if (!emitTree(&elemExpr->key())) {
// [stack] THIS KEY
return false;
}
} else {
if (!emitElemObjAndKey(elemExpr, false, eoe)) {
// [stack] OBJ KEY
return false;
}
}
if (!eoe.emitDelete()) {
// [stack] # if Super
// [stack] THIS
// [stack] # otherwise
// [stack] SUCCEEDED
return false;
}
return true;
}
bool BytecodeEmitter::emitDeleteExpression(UnaryNode* deleteNode) {
MOZ_ASSERT(deleteNode->isKind(ParseNodeKind::DeleteExpr));
ParseNode* expression = deleteNode->kid();
// If useless, just emit JSOp::True; otherwise convert |delete <expr>| to
// effectively |<expr>, true|.
bool useful = false;
if (!checkSideEffects(expression, &useful)) {
return false;
}
if (useful) {
if (!emitTree(expression)) {
return false;
}
if (!emit1(JSOp::Pop)) {
return false;
}
}
return emit1(JSOp::True);
}
bool BytecodeEmitter::emitDeleteOptionalChain(UnaryNode* deleteNode) {
MOZ_ASSERT(deleteNode->isKind(ParseNodeKind::DeleteOptionalChainExpr));
OptionalEmitter oe(this, bytecodeSection().stackDepth());
ParseNode* kid = deleteNode->kid();
switch (kid->getKind()) {
case ParseNodeKind::ElemExpr:
case ParseNodeKind::OptionalElemExpr: {
auto* elemExpr = &kid->as<PropertyByValueBase>();
if (!emitDeleteElementInOptChain(elemExpr, oe)) {
// [stack] # If shortcircuit
// [stack] UNDEFINED-OR-NULL
// [stack] # otherwise
// [stack] SUCCEEDED
return false;
}
break;
}
case ParseNodeKind::ArgumentsLength:
case ParseNodeKind::DotExpr:
case ParseNodeKind::OptionalDotExpr: {
auto* propExpr = &kid->as<PropertyAccessBase>();
if (!emitDeletePropertyInOptChain(propExpr, oe)) {
// [stack] # If shortcircuit
// [stack] UNDEFINED-OR-NULL
// [stack] # otherwise
// [stack] SUCCEEDED
return false;
}
break;
}
default:
MOZ_ASSERT_UNREACHABLE("Unrecognized optional delete ParseNodeKind");
}
if (!oe.emitOptionalJumpTarget(JSOp::True)) {
// [stack] # If shortcircuit
// [stack] TRUE
// [stack] # otherwise
// [stack] SUCCEEDED
return false;
}
return true;
}
bool BytecodeEmitter::emitDeletePropertyInOptChain(PropertyAccessBase* propExpr,
OptionalEmitter& oe) {
MOZ_ASSERT_IF(propExpr->is<PropertyAccess>(),
!propExpr->as<PropertyAccess>().isSuper());
PropOpEmitter poe(this, PropOpEmitter::Kind::Delete,
PropOpEmitter::ObjKind::Other);
if (!poe.prepareForObj()) {
// [stack]
return false;
}
if (!emitOptionalTree(&propExpr->expression(), oe)) {
// [stack] OBJ
return false;
}
if (propExpr->isKind(ParseNodeKind::OptionalDotExpr)) {
if (!oe.emitJumpShortCircuit()) {
// [stack] # if Jump
// [stack] UNDEFINED-OR-NULL
// [stack] # otherwise
// [stack] OBJ
return false;
}
}
if (!poe.emitDelete(propExpr->key().atom())) {
// [stack] SUCCEEDED
return false;
}
return true;
}
bool BytecodeEmitter::emitDeleteElementInOptChain(PropertyByValueBase* elemExpr,
OptionalEmitter& oe) {
MOZ_ASSERT_IF(elemExpr->is<PropertyByValue>(),
!elemExpr->as<PropertyByValue>().isSuper());
ElemOpEmitter eoe(this, ElemOpEmitter::Kind::Delete,
ElemOpEmitter::ObjKind::Other);
if (!eoe.prepareForObj()) {
// [stack]
return false;
}
if (!emitOptionalTree(&elemExpr->expression(), oe)) {
// [stack] OBJ
return false;
}
if (elemExpr->isKind(ParseNodeKind::OptionalElemExpr)) {
if (!oe.emitJumpShortCircuit()) {
// [stack] # if Jump
// [stack] UNDEFINED-OR-NULL
// [stack] # otherwise
// [stack] OBJ
return false;
}
}
if (!eoe.prepareForKey()) {
// [stack] OBJ
return false;
}
if (!emitTree(&elemExpr->key())) {
// [stack] OBJ KEY
return false;
}
if (!eoe.emitDelete()) {
// [stack] SUCCEEDED
return false;
}
return true;
}
bool BytecodeEmitter::emitDebugCheckSelfHosted() {
// [stack] CALLEE
#ifdef DEBUG
if (!emit1(JSOp::DebugCheckSelfHosted)) {
// [stack] CALLEE
return false;
}
#endif
return true;
}
bool BytecodeEmitter::emitSelfHostedCallFunction(CallNode* callNode, JSOp op) {
// Special-casing of callFunction to emit bytecode that directly
// invokes the callee with the correct |this| object and arguments.
// callFunction(fun, thisArg, arg0, arg1) thus becomes:
// - emit lookup for fun
// - emit lookup for thisArg
// - emit lookups for arg0, arg1
//
// argc is set to the amount of actually emitted args and the
// emitting of args below is disabled by setting emitArgs to false.
NameNode* calleeNode = &callNode->callee()->as<NameNode>();
ListNode* argsList = callNode->args();
MOZ_ASSERT(argsList->count() >= 2);
MOZ_ASSERT(callNode->callOp() == JSOp::Call);
bool constructing =
calleeNode->name() ==
TaggedParserAtomIndex::WellKnown::constructContentFunction();
ParseNode* funNode = argsList->head();
if (!emitTree(funNode)) {
// [stack] CALLEE
return false;
}
#ifdef DEBUG
MOZ_ASSERT(op == JSOp::Call || op == JSOp::CallContent ||
op == JSOp::NewContent);
if (op == JSOp::Call) {
if (!emitDebugCheckSelfHosted()) {
// [stack] CALLEE
return false;
}
}
#endif
ParseNode* thisOrNewTarget = funNode->pn_next;
if (constructing) {
// Save off the new.target value, but here emit a proper |this| for a
// constructing call.
if (!emit1(JSOp::IsConstructing)) {
// [stack] CALLEE IS_CONSTRUCTING
return false;
}
} else {
// It's |this|, emit it.
if (!emitTree(thisOrNewTarget)) {
// [stack] CALLEE THIS
return false;
}
}
for (ParseNode* argpn : argsList->contentsFrom(thisOrNewTarget->pn_next)) {
if (!emitTree(argpn)) {
// [stack] CALLEE ... ARGS...
return false;
}
}
if (constructing) {
if (!emitTree(thisOrNewTarget)) {
// [stack] CALLEE IS_CONSTRUCTING ARGS... NEW.TARGET
return false;
}
}
uint32_t argc = argsList->count() - 2;
if (!emitCall(op, argc)) {
// [stack] RVAL
return false;
}
return true;
}
bool BytecodeEmitter::emitSelfHostedResumeGenerator(CallNode* callNode) {
ListNode* argsList = callNode->args();
// Syntax: resumeGenerator(gen, value, 'next'|'throw'|'return')
MOZ_ASSERT(argsList->count() == 3);
ParseNode* genNode = argsList->head();
if (!emitTree(genNode)) {
// [stack] GENERATOR
return false;
}
ParseNode* valNode = genNode->pn_next;
if (!emitTree(valNode)) {
// [stack] GENERATOR VALUE
return false;
}
ParseNode* kindNode = valNode->pn_next;
MOZ_ASSERT(kindNode->isKind(ParseNodeKind::StringExpr));
GeneratorResumeKind kind =
ParserAtomToResumeKind(kindNode->as<NameNode>().atom());
MOZ_ASSERT(!kindNode->pn_next);
if (!emitPushResumeKind(kind)) {
// [stack] GENERATOR VALUE RESUMEKIND
return false;
}
if (!emit1(JSOp::Resume)) {
// [stack] RVAL
return false;
}
return true;
}
bool BytecodeEmitter::emitSelfHostedForceInterpreter() {
// JSScript::hasForceInterpreterOp() relies on JSOp::ForceInterpreter being
// the first bytecode op in the script.
MOZ_ASSERT(bytecodeSection().code().empty());
if (!emit1(JSOp::ForceInterpreter)) {
return false;
}
if (!emit1(JSOp::Undefined)) {
return false;
}
return true;
}
bool BytecodeEmitter::emitSelfHostedAllowContentIter(CallNode* callNode) {
ListNode* argsList = callNode->args();
MOZ_ASSERT(argsList->count() == 1);
// We're just here as a sentinel. Pass the value through directly.
return emitTree(argsList->head());
}
bool BytecodeEmitter::emitSelfHostedAllowContentIterWith(CallNode* callNode) {
ListNode* argsList = callNode->args();
MOZ_ASSERT(argsList->count() == 2 || argsList->count() == 3);
// We're just here as a sentinel. Pass the value through directly.
return emitTree(argsList->head());
}
bool BytecodeEmitter::emitSelfHostedAllowContentIterWithNext(
CallNode* callNode) {
ListNode* argsList = callNode->args();
MOZ_ASSERT(argsList->count() == 2);
// We're just here as a sentinel. Pass the value through directly.
return emitTree(argsList->head());
}
bool BytecodeEmitter::emitSelfHostedDefineDataProperty(CallNode* callNode) {
ListNode* argsList = callNode->args();
// Only optimize when 3 arguments are passed.
MOZ_ASSERT(argsList->count() == 3);
ParseNode* objNode = argsList->head();
if (!emitTree(objNode)) {
return false;
}
ParseNode* idNode = objNode->pn_next;
if (!emitTree(idNode)) {
return false;
}
ParseNode* valNode = idNode->pn_next;
if (!emitTree(valNode)) {
return false;
}
// This will leave the object on the stack instead of pushing |undefined|,
// but that's fine because the self-hosted code doesn't use the return
// value.
return emit1(JSOp::InitElem);
}
bool BytecodeEmitter::emitSelfHostedHasOwn(CallNode* callNode) {
ListNode* argsList = callNode->args();
MOZ_ASSERT(argsList->count() == 2);
ParseNode* idNode = argsList->head();
if (!emitTree(idNode)) {
return false;
}
ParseNode* objNode = idNode->pn_next;
if (!emitTree(objNode)) {
return false;
}
return emit1(JSOp::HasOwn);
}
bool BytecodeEmitter::emitSelfHostedGetPropertySuper(CallNode* callNode) {
ListNode* argsList = callNode->args();
MOZ_ASSERT(argsList->count() == 3);
ParseNode* objNode = argsList->head();
ParseNode* idNode = objNode->pn_next;
ParseNode* receiverNode = idNode->pn_next;
if (!emitTree(receiverNode)) {
return false;
}
if (!emitTree(idNode)) {
return false;
}
if (!emitTree(objNode)) {
return false;
}
return emitElemOpBase(JSOp::GetElemSuper);
}
bool BytecodeEmitter::emitSelfHostedToNumeric(CallNode* callNode) {
ListNode* argsList = callNode->args();
MOZ_ASSERT(argsList->count() == 1);
ParseNode* argNode = argsList->head();
if (!emitTree(argNode)) {
return false;
}
return emit1(JSOp::ToNumeric);
}
bool BytecodeEmitter::emitSelfHostedToString(CallNode* callNode) {
ListNode* argsList = callNode->args();
MOZ_ASSERT(argsList->count() == 1);
ParseNode* argNode = argsList->head();
if (!emitTree(argNode)) {
return false;
}
return emit1(JSOp::ToString);
}
bool BytecodeEmitter::emitSelfHostedIsNullOrUndefined(CallNode* callNode) {
ListNode* argsList = callNode->args();
MOZ_ASSERT(argsList->count() == 1);
ParseNode* argNode = argsList->head();
if (!emitTree(argNode)) {
// [stack] ARG
return false;
}
if (!emit1(JSOp::IsNullOrUndefined)) {
// [stack] ARG IS_NULL_OR_UNDEF
return false;
}
if (!emit1(JSOp::Swap)) {
// [stack] IS_NULL_OR_UNDEF ARG
return false;
}
if (!emit1(JSOp::Pop)) {
// [stack] IS_NULL_OR_UNDEF
return false;
}
return true;
}
bool BytecodeEmitter::emitSelfHostedIteratorClose(CallNode* callNode) {
ListNode* argsList = callNode->args();
MOZ_ASSERT(argsList->count() == 1);
ParseNode* argNode = argsList->head();
if (!emitTree(argNode)) {
// [stack] ARG
return false;
}
if (!emit2(JSOp::CloseIter, uint8_t(CompletionKind::Normal))) {
// [stack]
return false;
}
// This is still a call node, so we must generate a stack value.
if (!emit1(JSOp::Undefined)) {
// [stack] RVAL
return false;
}
return true;
}
bool BytecodeEmitter::emitSelfHostedGetBuiltinConstructorOrPrototype(
CallNode* callNode, bool isConstructor) {
ListNode* argsList = callNode->args();
MOZ_ASSERT(argsList->count() == 1);
ParseNode* argNode = argsList->head();
if (!argNode->isKind(ParseNodeKind::StringExpr)) {
reportError(callNode, JSMSG_UNEXPECTED_TYPE, "built-in name",
"not a string constant");
return false;
}
auto name = argNode->as<NameNode>().atom();
BuiltinObjectKind kind;
if (isConstructor) {
kind = BuiltinConstructorForName(name);
} else {
kind = BuiltinPrototypeForName(name);
}
if (kind == BuiltinObjectKind::None) {
reportError(callNode, JSMSG_UNEXPECTED_TYPE, "built-in name",
"not a valid built-in");
return false;
}
return emitBuiltinObject(kind);
}
bool BytecodeEmitter::emitSelfHostedGetBuiltinConstructor(CallNode* callNode) {
return emitSelfHostedGetBuiltinConstructorOrPrototype(
callNode, /* isConstructor = */ true);
}
bool BytecodeEmitter::emitSelfHostedGetBuiltinPrototype(CallNode* callNode) {
return emitSelfHostedGetBuiltinConstructorOrPrototype(
callNode, /* isConstructor = */ false);
}
JS::SymbolCode ParserAtomToSymbolCode(TaggedParserAtomIndex atom) {
// NOTE: This is a linear search, but the set of entries is quite small and
// this is only used for initial self-hosted parse.
#define MATCH_WELL_KNOWN_SYMBOL(NAME) \
if (atom == TaggedParserAtomIndex::WellKnown::NAME()) { \
return JS::SymbolCode::NAME; \
}
JS_FOR_EACH_WELL_KNOWN_SYMBOL(MATCH_WELL_KNOWN_SYMBOL)
#undef MATCH_WELL_KNOWN_SYMBOL
return JS::SymbolCode::Limit;
}
bool BytecodeEmitter::emitSelfHostedGetBuiltinSymbol(CallNode* callNode) {
ListNode* argsList = callNode->args();
MOZ_ASSERT(argsList->count() == 1);
ParseNode* argNode = argsList->head();
if (!argNode->isKind(ParseNodeKind::StringExpr)) {
reportError(callNode, JSMSG_UNEXPECTED_TYPE, "built-in name",
"not a string constant");
return false;
}
auto name = argNode->as<NameNode>().atom();
JS::SymbolCode code = ParserAtomToSymbolCode(name);
if (code == JS::SymbolCode::Limit) {
reportError(callNode, JSMSG_UNEXPECTED_TYPE, "built-in name",
"not a valid built-in");
return false;
}
return emit2(JSOp::Symbol, uint8_t(code));
}
bool BytecodeEmitter::emitSelfHostedArgumentsLength(CallNode* callNode) {
MOZ_ASSERT(!sc->asFunctionBox()->needsArgsObj());
sc->asFunctionBox()->setUsesArgumentsIntrinsics();
MOZ_ASSERT(callNode->args()->count() == 0);
return emit1(JSOp::ArgumentsLength);
}
bool BytecodeEmitter::emitSelfHostedGetArgument(CallNode* callNode) {
MOZ_ASSERT(!sc->asFunctionBox()->needsArgsObj());
sc->asFunctionBox()->setUsesArgumentsIntrinsics();
ListNode* argsList = callNode->args();
MOZ_ASSERT(argsList->count() == 1);
ParseNode* argNode = argsList->head();
if (!emitTree(argNode)) {
return false;
}
return emit1(JSOp::GetActualArg);
}
#ifdef DEBUG
void BytecodeEmitter::assertSelfHostedExpectedTopLevel(ParseNode* node) {
// The function argument is expected to be a simple binding/function name.
// Eg. `function foo() { }; SpecialIntrinsic(foo)`
MOZ_ASSERT(node->isKind(ParseNodeKind::Name),
"argument must be a function name");
TaggedParserAtomIndex targetName = node->as<NameNode>().name();
// The special intrinsics must follow the target functions definition. A
// simple assert is fine here since any hoisted function will cause a non-null
// value to be set here.
MOZ_ASSERT(prevSelfHostedTopLevelFunction);
// The target function must match the most recently defined top-level
// self-hosted function.
MOZ_ASSERT(prevSelfHostedTopLevelFunction->explicitName() == targetName,
"selfhost decorator must immediately follow target function");
}
#endif
bool BytecodeEmitter::emitSelfHostedSetIsInlinableLargeFunction(
CallNode* callNode) {
#ifdef DEBUG
ListNode* argsList = callNode->args();
MOZ_ASSERT(argsList->count() == 1);
assertSelfHostedExpectedTopLevel(argsList->head());
#endif
MOZ_ASSERT(prevSelfHostedTopLevelFunction->isInitialCompilation);
prevSelfHostedTopLevelFunction->setIsInlinableLargeFunction();
// This is still a call node, so we must generate a stack value.
return emit1(JSOp::Undefined);
}
bool BytecodeEmitter::emitSelfHostedSetCanonicalName(CallNode* callNode) {
ListNode* argsList = callNode->args();
MOZ_ASSERT(argsList->count() == 2);
#ifdef DEBUG
assertSelfHostedExpectedTopLevel(argsList->head());
#endif
ParseNode* nameNode = argsList->last();
MOZ_ASSERT(nameNode->isKind(ParseNodeKind::StringExpr));
TaggedParserAtomIndex specName = nameNode->as<NameNode>().atom();
// Canonical name must be atomized.
compilationState.parserAtoms.markUsedByStencil(specName,
ParserAtom::Atomize::Yes);
// Store the canonical name for instantiation.
prevSelfHostedTopLevelFunction->functionStencil().setSelfHostedCanonicalName(
specName);
return emit1(JSOp::Undefined);
}
#ifdef DEBUG
void BytecodeEmitter::assertSelfHostedUnsafeGetReservedSlot(
ListNode* argsList) {
MOZ_ASSERT(argsList->count() == 2);
ParseNode* objNode = argsList->head();
ParseNode* slotNode = objNode->pn_next;
// Ensure that the slot argument is fixed, this is required by the JITs.
MOZ_ASSERT(slotNode->isKind(ParseNodeKind::NumberExpr),
"slot argument must be a constant");
}
void BytecodeEmitter::assertSelfHostedUnsafeSetReservedSlot(
ListNode* argsList) {
MOZ_ASSERT(argsList->count() == 3);
ParseNode* objNode = argsList->head();
ParseNode* slotNode = objNode->pn_next;
// Ensure that the slot argument is fixed, this is required by the JITs.
MOZ_ASSERT(slotNode->isKind(ParseNodeKind::NumberExpr),
"slot argument must be a constant");
}
#endif
/* A version of emitCalleeAndThis for the optional cases:
* * a?.()
* * a?.b()
* * a?.["b"]()
* * (a?.b)()
* * a?.#b()
*
* See emitCallOrNew and emitOptionalCall for more context.
*/
bool BytecodeEmitter::emitOptionalCalleeAndThis(ParseNode* callee,
CallNode* call,
CallOrNewEmitter& cone,
OptionalEmitter& oe) {
AutoCheckRecursionLimit recursion(fc);
if (!recursion.check(fc)) {
return false;
}
switch (ParseNodeKind kind = callee->getKind()) {
case ParseNodeKind::Name: {
auto name = callee->as<NameNode>().name();
if (!cone.emitNameCallee(name)) {
// [stack] CALLEE THIS
return false;
}
break;
}
case ParseNodeKind::OptionalDotExpr: {
MOZ_ASSERT(emitterMode != BytecodeEmitter::SelfHosting);
OptionalPropertyAccess* prop = &callee->as<OptionalPropertyAccess>();
bool isSuper = false;
PropOpEmitter& poe = cone.prepareForPropCallee(isSuper);
if (!emitOptionalDotExpression(prop, poe, isSuper, oe)) {
// [stack] CALLEE THIS
return false;
}
break;
}
case ParseNodeKind::ArgumentsLength:
case ParseNodeKind::DotExpr: {
MOZ_ASSERT(emitterMode != BytecodeEmitter::SelfHosting);
PropertyAccess* prop = &callee->as<PropertyAccess>();
bool isSuper = prop->isSuper();
PropOpEmitter& poe = cone.prepareForPropCallee(isSuper);
if (!emitOptionalDotExpression(prop, poe, isSuper, oe)) {
// [stack] CALLEE THIS
return false;
}
break;
}
case ParseNodeKind::OptionalElemExpr: {
OptionalPropertyByValue* elem = &callee->as<OptionalPropertyByValue>();
bool isSuper = false;
MOZ_ASSERT(!elem->key().isKind(ParseNodeKind::PrivateName));
ElemOpEmitter& eoe = cone.prepareForElemCallee(isSuper);
if (!emitOptionalElemExpression(elem, eoe, isSuper, oe)) {
// [stack] CALLEE THIS
return false;
}
break;
}
case ParseNodeKind::ElemExpr: {
PropertyByValue* elem = &callee->as<PropertyByValue>();
bool isSuper = elem->isSuper();
MOZ_ASSERT(!elem->key().isKind(ParseNodeKind::PrivateName));
ElemOpEmitter& eoe = cone.prepareForElemCallee(isSuper);
if (!emitOptionalElemExpression(elem, eoe, isSuper, oe)) {
// [stack] CALLEE THIS
return false;
}
break;
}
case ParseNodeKind::PrivateMemberExpr:
case ParseNodeKind::OptionalPrivateMemberExpr: {
PrivateMemberAccessBase* privateExpr =
&callee->as<PrivateMemberAccessBase>();
PrivateOpEmitter& xoe =
cone.prepareForPrivateCallee(privateExpr->privateName().name());
if (!emitOptionalPrivateExpression(privateExpr, xoe, oe)) {
// [stack] CALLEE THIS
return false;
}
break;
}
case ParseNodeKind::Function:
if (!cone.prepareForFunctionCallee()) {
return false;
}
if (!emitOptionalTree(callee, oe)) {
// [stack] CALLEE
return false;
}
break;
case ParseNodeKind::OptionalChain: {
return emitCalleeAndThisForOptionalChain(&callee->as<UnaryNode>(), call,
cone);
}
default:
MOZ_RELEASE_ASSERT(kind != ParseNodeKind::SuperBase);
if (!cone.prepareForOtherCallee()) {
return false;
}
if (!emitOptionalTree(callee, oe)) {
// [stack] CALLEE
return false;
}
break;
}
if (!cone.emitThis()) {
// [stack] CALLEE THIS
return false;
}
return true;
}
bool BytecodeEmitter::emitCalleeAndThis(ParseNode* callee, CallNode* maybeCall,
CallOrNewEmitter& cone) {
MOZ_ASSERT_IF(maybeCall, maybeCall->callee() == callee);
switch (callee->getKind()) {
case ParseNodeKind::Name: {
auto name = callee->as<NameNode>().name();
if (!cone.emitNameCallee(name)) {
// [stack] CALLEE THIS?
return false;
}
break;
}
case ParseNodeKind::ArgumentsLength:
case ParseNodeKind::DotExpr: {
MOZ_ASSERT(emitterMode != BytecodeEmitter::SelfHosting);
PropertyAccess* prop = &callee->as<PropertyAccess>();
bool isSuper = prop->isSuper();
PropOpEmitter& poe = cone.prepareForPropCallee(isSuper);
if (!poe.prepareForObj()) {
return false;
}
if (isSuper) {
UnaryNode* base = &prop->expression().as<UnaryNode>();
if (!emitGetThisForSuperBase(base)) {
// [stack] THIS
return false;
}
} else {
if (!emitPropLHS(prop)) {
// [stack] OBJ
return false;
}
}
if (!poe.emitGet(prop->key().atom())) {
// [stack] CALLEE THIS?
return false;
}
break;
}
case ParseNodeKind::ElemExpr: {
MOZ_ASSERT(emitterMode != BytecodeEmitter::SelfHosting);
PropertyByValue* elem = &callee->as<PropertyByValue>();
bool isSuper = elem->isSuper();
MOZ_ASSERT(!elem->key().isKind(ParseNodeKind::PrivateName));
ElemOpEmitter& eoe = cone.prepareForElemCallee(isSuper);
if (!emitElemObjAndKey(elem, isSuper, eoe)) {
// [stack] # if Super
// [stack] THIS? THIS KEY
// [stack] # otherwise
// [stack] OBJ? OBJ KEY
return false;
}
if (!eoe.emitGet()) {
// [stack] CALLEE THIS?
return false;
}
break;
}
case ParseNodeKind::PrivateMemberExpr: {
MOZ_ASSERT(emitterMode != BytecodeEmitter::SelfHosting);
PrivateMemberAccessBase* privateExpr =
&callee->as<PrivateMemberAccessBase>();
PrivateOpEmitter& xoe =
cone.prepareForPrivateCallee(privateExpr->privateName().name());
if (!emitTree(&privateExpr->expression())) {
// [stack] OBJ
return false;
}
if (!xoe.emitReference()) {
// [stack] OBJ NAME
return false;
}
if (!xoe.emitGetForCallOrNew()) {
// [stack] CALLEE THIS
return false;
}
break;
}
case ParseNodeKind::Function:
if (!cone.prepareForFunctionCallee()) {
return false;
}
if (!emitTree(callee)) {
// [stack] CALLEE
return false;
}
break;
case ParseNodeKind::SuperBase:
MOZ_ASSERT(maybeCall);
MOZ_ASSERT(maybeCall->isKind(ParseNodeKind::SuperCallExpr));
MOZ_ASSERT(callee->isKind(ParseNodeKind::SuperBase));
if (!cone.emitSuperCallee()) {
// [stack] CALLEE IsConstructing
return false;
}
break;
case ParseNodeKind::OptionalChain: {
MOZ_ASSERT(maybeCall);
return emitCalleeAndThisForOptionalChain(&callee->as<UnaryNode>(),
maybeCall, cone);
}
default:
if (!cone.prepareForOtherCallee()) {
return false;
}
if (!emitTree(callee)) {
return false;
}
break;
}
if (!cone.emitThis()) {
// [stack] CALLEE THIS
return false;
}
return true;
}
ParseNode* BytecodeEmitter::getCoordNode(ParseNode* callNode,
ParseNode* calleeNode, JSOp op,
ListNode* argsList) {
ParseNode* coordNode = callNode;
if (op == JSOp::Call || op == JSOp::SpreadCall) {
// Default to using the location of the `(` itself.
// obj[expr]() // expression
// ^ // column coord
coordNode = argsList;
switch (calleeNode->getKind()) {
case ParseNodeKind::ArgumentsLength:
case ParseNodeKind::DotExpr:
// Use the position of a property access identifier.
//
// obj().aprop() // expression
// ^ // column coord
//
// Note: Because of the constant folding logic in FoldElement,
// this case also applies for constant string properties.
//
// obj()['aprop']() // expression
// ^ // column coord
coordNode = &calleeNode->as<PropertyAccess>().key();
break;
case ParseNodeKind::Name: {
// Use the start of callee name unless it is at a separator
// or has no args.
//
// 2 + obj() // expression
// ^ // column coord
//
if (argsList->empty() ||
!bytecodeSection().atSeparator(calleeNode->pn_pos.begin)) {
// Use the start of callee names.
coordNode = calleeNode;
}
break;
}
default:
break;
}
}
return coordNode;
}
bool BytecodeEmitter::emitArguments(ListNode* argsList, bool isCall,
bool isSpread, CallOrNewEmitter& cone) {
uint32_t argc = argsList->count();
if (argc >= ARGC_LIMIT) {
reportError(argsList,
isCall ? JSMSG_TOO_MANY_FUN_ARGS : JSMSG_TOO_MANY_CON_ARGS);
return false;
}
if (!isSpread) {
if (!cone.prepareForNonSpreadArguments()) {
// [stack] CALLEE THIS
return false;
}
for (ParseNode* arg : argsList->contents()) {
if (!updateSourceCoordNotesIfNonLiteral(arg)) {
return false;
}
if (!emitTree(arg)) {
// [stack] CALLEE THIS ARG*
return false;
}
}
} else if (cone.wantSpreadOperand()) {
auto* spreadNode = &argsList->head()->as<UnaryNode>();
if (!updateSourceCoordNotesIfNonLiteral(spreadNode->kid())) {
return false;
}
if (!emitTree(spreadNode->kid())) {
// [stack] CALLEE THIS ARG0
return false;
}
if (!cone.emitSpreadArgumentsTest()) {
// [stack] CALLEE THIS ARG0
return false;
}
if (cone.wantSpreadIteration()) {
if (!emitSpreadIntoArray(spreadNode)) {
// [stack] CALLEE THIS ARR
return false;
}
}
if (!cone.emitSpreadArgumentsTestEnd()) {
// [stack] CALLEE THIS ARR
return false;
}
} else {
if (!cone.prepareForSpreadArguments()) {
// [stack] CALLEE THIS
return false;
}
if (!emitArray(argsList)) {
// [stack] CALLEE THIS ARR
return false;
}
}
return true;
}
bool BytecodeEmitter::emitOptionalCall(CallNode* callNode, OptionalEmitter& oe,
ValueUsage valueUsage) {
/*
* A modified version of emitCallOrNew that handles optional calls.
*
* These include the following:
* a?.()
* a.b?.()
* a.["b"]?.()
* (a?.b)?.()
*
* See CallOrNewEmitter for more context.
*/
ParseNode* calleeNode = callNode->callee();
ListNode* argsList = callNode->args();
bool isSpread = IsSpreadOp(callNode->callOp());
JSOp op = callNode->callOp();
uint32_t argc = argsList->count();
bool isOptimizableSpread = isSpread && argc == 1;
CallOrNewEmitter cone(this, op,
isOptimizableSpread
? CallOrNewEmitter::ArgumentsKind::SingleSpread
: CallOrNewEmitter::ArgumentsKind::Other,
valueUsage);
ParseNode* coordNode = getCoordNode(callNode, calleeNode, op, argsList);
if (!emitOptionalCalleeAndThis(calleeNode, callNode, cone, oe)) {
// [stack] CALLEE THIS
return false;
}
if (callNode->isKind(ParseNodeKind::OptionalCallExpr)) {
if (!oe.emitJumpShortCircuitForCall()) {
// [stack] CALLEE THIS
return false;
}
}
if (!emitArguments(argsList, /* isCall = */ true, isSpread, cone)) {
// [stack] CALLEE THIS ARGS...
return false;
}
if (!cone.emitEnd(argc, coordNode->pn_pos.begin)) {
// [stack] RVAL
return false;
}
return true;
}
bool BytecodeEmitter::emitCallOrNew(CallNode* callNode, ValueUsage valueUsage) {
/*
* Emit callable invocation or operator new (constructor call) code.
* First, emit code for the left operand to evaluate the callable or
* constructable object expression.
*
* Then (or in a call case that has no explicit reference-base
* object) we emit JSOp::Undefined to produce the undefined |this|
* value required for calls (which non-strict mode functions
* will box into the global object).
*/
bool isCall = callNode->isKind(ParseNodeKind::CallExpr) ||
callNode->isKind(ParseNodeKind::TaggedTemplateExpr);
ParseNode* calleeNode = callNode->callee();
ListNode* argsList = callNode->args();
JSOp op = callNode->callOp();
if (calleeNode->isKind(ParseNodeKind::Name) &&
emitterMode == BytecodeEmitter::SelfHosting && op == JSOp::Call) {
// Calls to "forceInterpreter", "callFunction",
// "callContentFunction", or "resumeGenerator" in self-hosted
// code generate inline bytecode.
//
// NOTE: The list of special instruction names has to be kept in sync with
// "js/src/builtin/.eslintrc.js".
auto calleeName = calleeNode->as<NameNode>().name();
if (calleeName == TaggedParserAtomIndex::WellKnown::callFunction()) {
return emitSelfHostedCallFunction(callNode, JSOp::Call);
}
if (calleeName == TaggedParserAtomIndex::WellKnown::callContentFunction()) {
return emitSelfHostedCallFunction(callNode, JSOp::CallContent);
}
if (calleeName ==
TaggedParserAtomIndex::WellKnown::constructContentFunction()) {
return emitSelfHostedCallFunction(callNode, JSOp::NewContent);
}
if (calleeName == TaggedParserAtomIndex::WellKnown::resumeGenerator()) {
return emitSelfHostedResumeGenerator(callNode);
}
if (calleeName == TaggedParserAtomIndex::WellKnown::forceInterpreter()) {
return emitSelfHostedForceInterpreter();
}
if (calleeName == TaggedParserAtomIndex::WellKnown::allowContentIter()) {
return emitSelfHostedAllowContentIter(callNode);
}
if (calleeName ==
TaggedParserAtomIndex::WellKnown::allowContentIterWith()) {
return emitSelfHostedAllowContentIterWith(callNode);
}
if (calleeName ==
TaggedParserAtomIndex::WellKnown::allowContentIterWithNext()) {
return emitSelfHostedAllowContentIterWithNext(callNode);
}
if (calleeName == TaggedParserAtomIndex::WellKnown::DefineDataProperty() &&
argsList->count() == 3) {
return emitSelfHostedDefineDataProperty(callNode);
}
if (calleeName == TaggedParserAtomIndex::WellKnown::hasOwn()) {
return emitSelfHostedHasOwn(callNode);
}
if (calleeName == TaggedParserAtomIndex::WellKnown::getPropertySuper()) {
return emitSelfHostedGetPropertySuper(callNode);
}
if (calleeName == TaggedParserAtomIndex::WellKnown::ToNumeric()) {
return emitSelfHostedToNumeric(callNode);
}
if (calleeName == TaggedParserAtomIndex::WellKnown::ToString()) {
return emitSelfHostedToString(callNode);
}
if (calleeName ==
TaggedParserAtomIndex::WellKnown::GetBuiltinConstructor()) {
return emitSelfHostedGetBuiltinConstructor(callNode);
}
if (calleeName == TaggedParserAtomIndex::WellKnown::GetBuiltinPrototype()) {
return emitSelfHostedGetBuiltinPrototype(callNode);
}
if (calleeName == TaggedParserAtomIndex::WellKnown::GetBuiltinSymbol()) {
return emitSelfHostedGetBuiltinSymbol(callNode);
}
if (calleeName == TaggedParserAtomIndex::WellKnown::ArgumentsLength()) {
return emitSelfHostedArgumentsLength(callNode);
}
if (calleeName == TaggedParserAtomIndex::WellKnown::GetArgument()) {
return emitSelfHostedGetArgument(callNode);
}
if (calleeName ==
TaggedParserAtomIndex::WellKnown::SetIsInlinableLargeFunction()) {
return emitSelfHostedSetIsInlinableLargeFunction(callNode);
}
if (calleeName == TaggedParserAtomIndex::WellKnown::SetCanonicalName()) {
return emitSelfHostedSetCanonicalName(callNode);
}
if (calleeName == TaggedParserAtomIndex::WellKnown::IsNullOrUndefined()) {
return emitSelfHostedIsNullOrUndefined(callNode);
}
if (calleeName == TaggedParserAtomIndex::WellKnown::IteratorClose()) {
return emitSelfHostedIteratorClose(callNode);
}
#ifdef DEBUG
if (calleeName ==
TaggedParserAtomIndex::WellKnown::UnsafeGetReservedSlot() ||
calleeName == TaggedParserAtomIndex::WellKnown::
UnsafeGetObjectFromReservedSlot() ||
calleeName == TaggedParserAtomIndex::WellKnown::
UnsafeGetInt32FromReservedSlot() ||
calleeName == TaggedParserAtomIndex::WellKnown::
UnsafeGetStringFromReservedSlot()) {
// Make sure that this call is correct, but don't emit any special code.
assertSelfHostedUnsafeGetReservedSlot(argsList);
}
if (calleeName ==
TaggedParserAtomIndex::WellKnown::UnsafeSetReservedSlot()) {
// Make sure that this call is correct, but don't emit any special code.
assertSelfHostedUnsafeSetReservedSlot(argsList);
}
#endif
// Fall through
}
uint32_t argc = argsList->count();
bool isSpread = IsSpreadOp(op);
bool isOptimizableSpread = isSpread && argc == 1;
bool isDefaultDerivedClassConstructor =
sc->isFunctionBox() && sc->asFunctionBox()->isDerivedClassConstructor() &&
sc->asFunctionBox()->isSyntheticFunction();
MOZ_ASSERT_IF(isDefaultDerivedClassConstructor, isOptimizableSpread);
CallOrNewEmitter cone(
this, op,
isOptimizableSpread
? isDefaultDerivedClassConstructor
? CallOrNewEmitter::ArgumentsKind::PassthroughRest
: CallOrNewEmitter::ArgumentsKind::SingleSpread
: CallOrNewEmitter::ArgumentsKind::Other,
valueUsage);
if (!emitCalleeAndThis(calleeNode, callNode, cone)) {
// [stack] CALLEE THIS
return false;
}
if (!emitArguments(argsList, isCall, isSpread, cone)) {
// [stack] CALLEE THIS ARGS...
return false;
}
// Push new.target for construct calls.
if (IsConstructOp(op)) {
if (op == JSOp::SuperCall || op == JSOp::SpreadSuperCall) {
if (!emitNewTarget(callNode)) {
// [stack] CALLEE THIS ARGS.. NEW.TARGET
return false;
}
} else {
// Repush the callee as new.target
uint32_t effectiveArgc = isSpread ? 1 : argc;
if (!emitDupAt(effectiveArgc + 1)) {
// [stack] CALLEE THIS ARGS.. CALLEE
return false;
}
}
}
ParseNode* coordNode = getCoordNode(callNode, calleeNode, op, argsList);
if (!cone.emitEnd(argc, coordNode->pn_pos.begin)) {
// [stack] RVAL
return false;
}
return true;
}
// This list must be kept in the same order in several places:
// - The binary operators in ParseNode.h ,
// - the binary operators in TokenKind.h
// - the precedence list in Parser.cpp
static const JSOp ParseNodeKindToJSOp[] = {
// Some binary ops require special code generation (PrivateIn);
// these should not use BinaryOpParseNodeKindToJSOp. This table fills those
// slots with Nops to make the rest of the table lookup work.
JSOp::Coalesce, JSOp::Or, JSOp::And, JSOp::BitOr, JSOp::BitXor,
JSOp::BitAnd, JSOp::StrictEq, JSOp::Eq, JSOp::StrictNe, JSOp::Ne,
JSOp::Lt, JSOp::Le, JSOp::Gt, JSOp::Ge, JSOp::Instanceof,
JSOp::In, JSOp::Nop, JSOp::Lsh, JSOp::Rsh, JSOp::Ursh,
JSOp::Add, JSOp::Sub, JSOp::Mul, JSOp::Div, JSOp::Mod,
JSOp::Pow};
static inline JSOp BinaryOpParseNodeKindToJSOp(ParseNodeKind pnk) {
MOZ_ASSERT(pnk >= ParseNodeKind::BinOpFirst);
MOZ_ASSERT(pnk <= ParseNodeKind::BinOpLast);
int parseNodeFirst = size_t(ParseNodeKind::BinOpFirst);
#ifdef DEBUG
int jsopArraySize = std::size(ParseNodeKindToJSOp);
int parseNodeKindListSize =
size_t(ParseNodeKind::BinOpLast) - parseNodeFirst + 1;
MOZ_ASSERT(jsopArraySize == parseNodeKindListSize);
// Ensure we don't use this to find an op for a parse node
// requiring special emission rules.
MOZ_ASSERT(ParseNodeKindToJSOp[size_t(pnk) - parseNodeFirst] != JSOp::Nop);
#endif
return ParseNodeKindToJSOp[size_t(pnk) - parseNodeFirst];
}
bool BytecodeEmitter::emitRightAssociative(ListNode* node) {
// ** is the only right-associative operator.
MOZ_ASSERT(node->isKind(ParseNodeKind::PowExpr));
// Right-associative operator chain.
for (ParseNode* subexpr : node->contents()) {
if (!updateSourceCoordNotesIfNonLiteral(subexpr)) {
return false;
}
if (!emitTree(subexpr)) {
return false;
}
}
for (uint32_t i = 0; i < node->count() - 1; i++) {
if (!emit1(JSOp::Pow)) {
return false;
}
}
return true;
}
bool BytecodeEmitter::emitLeftAssociative(ListNode* node) {
// Left-associative operator chain.
if (!emitTree(node->head())) {
return false;
}
JSOp op = BinaryOpParseNodeKindToJSOp(node->getKind());
ParseNode* nextExpr = node->head()->pn_next;
do {
if (!updateSourceCoordNotesIfNonLiteral(nextExpr)) {
return false;
}
if (!emitTree(nextExpr)) {
return false;
}
if (!emit1(op)) {
return false;
}
} while ((nextExpr = nextExpr->pn_next));
return true;
}
bool BytecodeEmitter::emitPrivateInExpr(ListNode* node) {
MOZ_ASSERT(node->head()->isKind(ParseNodeKind::PrivateName));
NameNode& privateNameNode = node->head()->as<NameNode>();
TaggedParserAtomIndex privateName = privateNameNode.name();
PrivateOpEmitter xoe(this, PrivateOpEmitter::Kind::ErgonomicBrandCheck,
privateName);
ParseNode* valueNode = node->head()->pn_next;
MOZ_ASSERT(valueNode->pn_next == nullptr);
if (!emitTree(valueNode)) {
// [stack] OBJ
return false;
}
if (!xoe.emitReference()) {
// [stack] OBJ BRAND if private method
// [stack] OBJ NAME if private field or accessor.
return false;
}
if (!xoe.emitBrandCheck()) {
// [stack] OBJ BRAND BOOL if private method
// [stack] OBJ NAME BOOL if private field or accessor.
return false;
}
if (!emitUnpickN(2)) {
// [stack] BOOL OBJ BRAND if private method
// [stack] BOOL OBJ NAME if private field or accessor.
return false;
}
if (!emitPopN(2)) {
// [stack] BOOL
return false;
}
return true;
}
/*
* Special `emitTree` for Optional Chaining case.
* Examples of this are `emitOptionalChain`, `emitDeleteOptionalChain` and
* `emitCalleeAndThisForOptionalChain`.
*/
bool BytecodeEmitter::emitOptionalTree(
ParseNode* pn, OptionalEmitter& oe,
ValueUsage valueUsage /* = ValueUsage::WantValue */) {
AutoCheckRecursionLimit recursion(fc);
if (!recursion.check(fc)) {
return false;
}
ParseNodeKind kind = pn->getKind();
switch (kind) {
case ParseNodeKind::OptionalDotExpr: {
OptionalPropertyAccess* prop = &pn->as<OptionalPropertyAccess>();
bool isSuper = false;
PropOpEmitter poe(this, PropOpEmitter::Kind::Get,
PropOpEmitter::ObjKind::Other);
if (!emitOptionalDotExpression(prop, poe, isSuper, oe)) {
return false;
}
break;
}
case ParseNodeKind::ArgumentsLength:
case ParseNodeKind::DotExpr: {
PropertyAccess* prop = &pn->as<PropertyAccess>();
bool isSuper = prop->isSuper();
PropOpEmitter poe(this, PropOpEmitter::Kind::Get,
isSuper ? PropOpEmitter::ObjKind::Super
: PropOpEmitter::ObjKind::Other);
if (!emitOptionalDotExpression(prop, poe, isSuper, oe)) {
return false;
}
break;
}
case ParseNodeKind::OptionalElemExpr: {
OptionalPropertyByValue* elem = &pn->as<OptionalPropertyByValue>();
bool isSuper = false;
MOZ_ASSERT(!elem->key().isKind(ParseNodeKind::PrivateName));
ElemOpEmitter eoe(this, ElemOpEmitter::Kind::Get,
ElemOpEmitter::ObjKind::Other);
if (!emitOptionalElemExpression(elem, eoe, isSuper, oe)) {
return false;
}
break;
}
case ParseNodeKind::ElemExpr: {
PropertyByValue* elem = &pn->as<PropertyByValue>();
bool isSuper = elem->isSuper();
MOZ_ASSERT(!elem->key().isKind(ParseNodeKind::PrivateName));
ElemOpEmitter eoe(this, ElemOpEmitter::Kind::Get,
isSuper ? ElemOpEmitter::ObjKind::Super
: ElemOpEmitter::ObjKind::Other);
if (!emitOptionalElemExpression(elem, eoe, isSuper, oe)) {
return false;
}
break;
}
case ParseNodeKind::PrivateMemberExpr:
case ParseNodeKind::OptionalPrivateMemberExpr: {
PrivateMemberAccessBase* privateExpr = &pn->as<PrivateMemberAccessBase>();
PrivateOpEmitter xoe(this, PrivateOpEmitter::Kind::Get,
privateExpr->privateName().name());
if (!emitOptionalPrivateExpression(privateExpr, xoe, oe)) {
return false;
}
break;
}
case ParseNodeKind::CallExpr:
case ParseNodeKind::OptionalCallExpr:
if (!emitOptionalCall(&pn->as<CallNode>(), oe, valueUsage)) {
return false;
}
break;
// List of accepted ParseNodeKinds that might appear only at the beginning
// of an Optional Chain.
// For example, a taggedTemplateExpr node might occur if we have
// `test`?.b, with `test` as the taggedTemplateExpr ParseNode.
default:
#ifdef DEBUG
bool isPrimaryExpression =
kind == ParseNodeKind::ThisExpr || kind == ParseNodeKind::Name ||
kind == ParseNodeKind::PrivateName ||
kind == ParseNodeKind::NullExpr || kind == ParseNodeKind::TrueExpr ||
kind == ParseNodeKind::FalseExpr ||
kind == ParseNodeKind::NumberExpr ||
kind == ParseNodeKind::BigIntExpr ||
kind == ParseNodeKind::StringExpr ||
kind == ParseNodeKind::ArrayExpr ||
kind == ParseNodeKind::ObjectExpr ||
kind == ParseNodeKind::Function || kind == ParseNodeKind::ClassDecl ||
kind == ParseNodeKind::RegExpExpr ||
kind == ParseNodeKind::TemplateStringExpr ||
kind == ParseNodeKind::TemplateStringListExpr ||
kind == ParseNodeKind::RawUndefinedExpr || pn->isInParens();
bool isMemberExpression = isPrimaryExpression ||
kind == ParseNodeKind::TaggedTemplateExpr ||
kind == ParseNodeKind::NewExpr ||
kind == ParseNodeKind::NewTargetExpr ||
kind == ParseNodeKind::ImportMetaExpr;
bool isCallExpression = kind == ParseNodeKind::SetThis ||
kind == ParseNodeKind::CallImportExpr;
MOZ_ASSERT(isMemberExpression || isCallExpression,
"Unknown ParseNodeKind for OptionalChain");
#endif
return emitTree(pn);
}
return true;
}
// Handle the case of a call made on a OptionalChainParseNode.
// For example `(a?.b)()` and `(a?.b)?.()`.
bool BytecodeEmitter::emitCalleeAndThisForOptionalChain(
UnaryNode* optionalChain, CallNode* callNode, CallOrNewEmitter& cone) {
ParseNode* calleeNode = optionalChain->kid();
// Create a new OptionalEmitter, in order to emit the right bytecode
// in isolation.
OptionalEmitter oe(this, bytecodeSection().stackDepth());
if (!emitOptionalCalleeAndThis(calleeNode, callNode, cone, oe)) {
// [stack] CALLEE THIS
return false;
}
// complete the jump if necessary. This will set both the "this" value
// and the "callee" value to undefined, if the callee is undefined. It
// does not matter much what the this value is, the function call will
// fail if it is not optional, and be set to undefined otherwise.
if (!oe.emitOptionalJumpTarget(JSOp::Undefined,
OptionalEmitter::Kind::Reference)) {
// [stack] # If shortcircuit
// [stack] UNDEFINED UNDEFINED
// [stack] # otherwise
// [stack] CALLEE THIS
return false;
}
return true;
}
bool BytecodeEmitter::emitOptionalChain(UnaryNode* optionalChain,
ValueUsage valueUsage) {
ParseNode* expr = optionalChain->kid();
OptionalEmitter oe(this, bytecodeSection().stackDepth());
if (!emitOptionalTree(expr, oe, valueUsage)) {
// [stack] VAL
return false;
}
if (!oe.emitOptionalJumpTarget(JSOp::Undefined)) {
// [stack] # If shortcircuit
// [stack] UNDEFINED
// [stack] # otherwise
// [stack] VAL
return false;
}
return true;
}
bool BytecodeEmitter::emitOptionalDotExpression(PropertyAccessBase* prop,
PropOpEmitter& poe,
bool isSuper,
OptionalEmitter& oe) {
if (!poe.prepareForObj()) {
// [stack]
return false;
}
if (isSuper) {
UnaryNode* base = &prop->expression().as<UnaryNode>();
if (!emitGetThisForSuperBase(base)) {
// [stack] OBJ
return false;
}
} else {
if (!emitOptionalTree(&prop->expression(), oe)) {
// [stack] OBJ
return false;
}
}
if (prop->isKind(ParseNodeKind::OptionalDotExpr)) {
MOZ_ASSERT(!isSuper);
if (!oe.emitJumpShortCircuit()) {
// [stack] # if Jump
// [stack] UNDEFINED-OR-NULL
// [stack] # otherwise
// [stack] OBJ
return false;
}
}
if (!poe.emitGet(prop->key().atom())) {
// [stack] PROP
return false;
}
return true;
}
bool BytecodeEmitter::emitOptionalElemExpression(PropertyByValueBase* elem,
ElemOpEmitter& eoe,
bool isSuper,
OptionalEmitter& oe) {
if (!eoe.prepareForObj()) {
// [stack]
return false;
}
if (isSuper) {
UnaryNode* base = &elem->expression().as<UnaryNode>();
if (!emitGetThisForSuperBase(base)) {
// [stack] OBJ
return false;
}
} else {
if (!emitOptionalTree(&elem->expression(), oe)) {
// [stack] OBJ
return false;
}
}
if (elem->isKind(ParseNodeKind::OptionalElemExpr)) {
MOZ_ASSERT(!isSuper);
if (!oe.emitJumpShortCircuit()) {
// [stack] # if Jump
// [stack] UNDEFINED-OR-NULL
// [stack] # otherwise
// [stack] OBJ
return false;
}
}
if (!eoe.prepareForKey()) {
// [stack] OBJ? OBJ
return false;
}
if (!emitTree(&elem->key())) {
// [stack] OBJ? OBJ KEY
return false;
}
if (!eoe.emitGet()) {
// [stack] ELEM
return false;
}
return true;
}
bool BytecodeEmitter::emitOptionalPrivateExpression(
PrivateMemberAccessBase* privateExpr, PrivateOpEmitter& xoe,
OptionalEmitter& oe) {
if (!emitOptionalTree(&privateExpr->expression(), oe)) {
// [stack] OBJ
return false;
}
if (privateExpr->isKind(ParseNodeKind::OptionalPrivateMemberExpr)) {
if (!oe.emitJumpShortCircuit()) {
// [stack] # if Jump
// [stack] UNDEFINED-OR-NULL
// [stack] # otherwise
// [stack] OBJ
return false;
}
}
if (!xoe.emitReference()) {
// [stack] OBJ NAME
return false;
}
if (!xoe.emitGet()) {
// [stack] CALLEE THIS # if call
// [stack] VALUE # otherwise
return false;
}
return true;
}
bool BytecodeEmitter::emitShortCircuit(ListNode* node, ValueUsage valueUsage) {
MOZ_ASSERT(node->isKind(ParseNodeKind::OrExpr) ||
node->isKind(ParseNodeKind::CoalesceExpr) ||
node->isKind(ParseNodeKind::AndExpr));
/*
* JSOp::Or converts the operand on the stack to boolean, leaves the original
* value on the stack and jumps if true; otherwise it falls into the next
* bytecode, which pops the left operand and then evaluates the right operand.
* The jump goes around the right operand evaluation.
*
* JSOp::And converts the operand on the stack to boolean and jumps if false;
* otherwise it falls into the right operand's bytecode.
*/
TDZCheckCache tdzCache(this);
JSOp op;
switch (node->getKind()) {
case ParseNodeKind::OrExpr:
op = JSOp::Or;
break;
case ParseNodeKind::CoalesceExpr:
op = JSOp::Coalesce;
break;
case ParseNodeKind::AndExpr:
op = JSOp::And;
break;
default:
MOZ_CRASH("Unexpected ParseNodeKind");
}
JumpList jump;
// Left-associative operator chain: avoid too much recursion.
//
// Emit all nodes but the last.
for (ParseNode* expr : node->contentsTo(node->last())) {
if (!emitTree(expr)) {
return false;
}
if (!emitJump(op, &jump)) {
return false;
}
if (!emit1(JSOp::Pop)) {
return false;
}
}
// Emit the last node
if (!emitTree(node->last(), valueUsage)) {
return false;
}
if (!emitJumpTargetAndPatch(jump)) {
return false;
}
return true;
}
bool BytecodeEmitter::emitSequenceExpr(ListNode* node, ValueUsage valueUsage) {
for (ParseNode* child : node->contentsTo(node->last())) {
if (!updateSourceCoordNotes(child->pn_pos.begin)) {
return false;
}
if (!emitTree(child, ValueUsage::IgnoreValue)) {
return false;
}
if (!emit1(JSOp::Pop)) {
return false;
}
}
ParseNode* child = node->last();
if (!updateSourceCoordNotes(child->pn_pos.begin)) {
return false;
}
if (!emitTree(child, valueUsage)) {
return false;
}
return true;
}
// Using MOZ_NEVER_INLINE in here is a workaround for llvm.org/pr14047. See
// the comment on emitSwitch.
MOZ_NEVER_INLINE bool BytecodeEmitter::emitIncOrDec(UnaryNode* incDec,
ValueUsage valueUsage) {
switch (incDec->kid()->getKind()) {
case ParseNodeKind::ArgumentsLength:
case ParseNodeKind::DotExpr:
return emitPropIncDec(incDec, valueUsage);
case ParseNodeKind::ElemExpr:
return emitElemIncDec(incDec, valueUsage);
case ParseNodeKind::PrivateMemberExpr:
return emitPrivateIncDec(incDec, valueUsage);
case ParseNodeKind::CallExpr:
return emitCallIncDec(incDec);
default:
return emitNameIncDec(incDec, valueUsage);
}
}
// Using MOZ_NEVER_INLINE in here is a workaround for llvm.org/pr14047. See
// the comment on emitSwitch.
MOZ_NEVER_INLINE bool BytecodeEmitter::emitLabeledStatement(
const LabeledStatement* labeledStmt) {
auto name = labeledStmt->label();
LabelEmitter label(this);
label.emitLabel(name);
if (!emitTree(labeledStmt->statement())) {
return false;
}
if (!label.emitEnd()) {
return false;
}
return true;
}
bool BytecodeEmitter::emitConditionalExpression(
ConditionalExpression& conditional, ValueUsage valueUsage) {
CondEmitter cond(this);
if (!cond.emitCond()) {
return false;
}
ParseNode* conditionNode = &conditional.condition();
auto conditionKind = IfEmitter::ConditionKind::Positive;
if (conditionNode->isKind(ParseNodeKind::NotExpr)) {
conditionNode = conditionNode->as<UnaryNode>().kid();
conditionKind = IfEmitter::ConditionKind::Negative;
}
// NOTE: NotExpr of conditionNode may be unwrapped, and in that case the
// negation is handled by conditionKind.
if (!emitTree(conditionNode)) {
return false;
}
if (!cond.emitThenElse(conditionKind)) {
return false;
}
if (!emitTree(&conditional.thenExpression(), valueUsage)) {
return false;
}
if (!cond.emitElse()) {
return false;
}
if (!emitTree(&conditional.elseExpression(), valueUsage)) {
return false;
}
if (!cond.emitEnd()) {
return false;
}
MOZ_ASSERT(cond.pushed() == 1);
return true;
}
// Check for an object-literal property list that can be handled by the
// ObjLiteral writer. We ensure that for each `prop: value` pair, the key is a
// constant name or numeric index, there is no accessor specified, and the value
// can be encoded by an ObjLiteral instruction (constant number, string,
// boolean, null/undefined).
void BytecodeEmitter::isPropertyListObjLiteralCompatible(ListNode* obj,
bool* withValues,
bool* withoutValues) {
bool keysOK = true;
bool valuesOK = true;
uint32_t propCount = 0;
for (ParseNode* propdef : obj->contents()) {
if (!propdef->is<BinaryNode>()) {
keysOK = false;
break;
}
propCount++;
BinaryNode* prop = &propdef->as<BinaryNode>();
ParseNode* key = prop->left();
ParseNode* value = prop->right();
// Computed keys not OK (ObjLiteral data stores constant keys).
if (key->isKind(ParseNodeKind::ComputedName)) {
keysOK = false;
break;
}
// BigIntExprs should have been lowered to computed names at parse
// time, and so should be excluded above.
MOZ_ASSERT(!key->isKind(ParseNodeKind::BigIntExpr));
// Numeric keys OK as long as they are integers and in range.
if (key->isKind(ParseNodeKind::NumberExpr)) {
double numValue = key->as<NumericLiteral>().value();
int32_t i = 0;
if (!NumberIsInt32(numValue, &i)) {
keysOK = false;
break;
}
if (!ObjLiteralWriter::arrayIndexInRange(i)) {
keysOK = false;
break;
}
}
MOZ_ASSERT(key->isKind(ParseNodeKind::ObjectPropertyName) ||
key->isKind(ParseNodeKind::StringExpr) ||
key->isKind(ParseNodeKind::NumberExpr));
AccessorType accessorType =
prop->is<PropertyDefinition>()
? prop->as<PropertyDefinition>().accessorType()
: AccessorType::None;
if (accessorType != AccessorType::None) {
keysOK = false;
break;
}
if (!isRHSObjLiteralCompatible(value)) {
valuesOK = false;
}
}
if (propCount > SharedPropMap::MaxPropsForNonDictionary) {
// JSOp::NewObject cannot accept dictionary-mode objects.
keysOK = false;
}
*withValues = keysOK && valuesOK;
*withoutValues = keysOK;
}
bool BytecodeEmitter::isArrayObjLiteralCompatible(ListNode* array) {
for (ParseNode* elem : array->contents()) {
if (elem->isKind(ParseNodeKind::Spread)) {
return false;
}
if (!isRHSObjLiteralCompatible(elem)) {
return false;
}
}
return true;
}
bool BytecodeEmitter::emitPropertyList(ListNode* obj, PropertyEmitter& pe,
PropListType type) {
// [stack] CTOR? OBJ
size_t curFieldKeyIndex = 0;
size_t curStaticFieldKeyIndex = 0;
for (ParseNode* propdef : obj->contents()) {
if (propdef->is<ClassField>()) {
MOZ_ASSERT(type == ClassBody);
// Only handle computing field keys here: the .initializers lambda array
// is created elsewhere.
ClassField* field = &propdef->as<ClassField>();
if (field->name().getKind() == ParseNodeKind::ComputedName) {
auto fieldKeys =
field->isStatic()
? TaggedParserAtomIndex::WellKnown::dot_staticFieldKeys_()
: TaggedParserAtomIndex::WellKnown::dot_fieldKeys_();
if (!emitGetName(fieldKeys)) {
// [stack] CTOR OBJ ARRAY
return false;
}
ParseNode* nameExpr = field->name().as<UnaryNode>().kid();
if (!emitTree(nameExpr, ValueUsage::WantValue)) {
// [stack] CTOR OBJ ARRAY KEY
return false;
}
if (!emit1(JSOp::ToPropertyKey)) {
// [stack] CTOR OBJ ARRAY KEY
return false;
}
size_t fieldKeysIndex;
if (field->isStatic()) {
fieldKeysIndex = curStaticFieldKeyIndex++;
} else {
fieldKeysIndex = curFieldKeyIndex++;
}
if (!emitUint32Operand(JSOp::InitElemArray, fieldKeysIndex)) {
// [stack] CTOR OBJ ARRAY
return false;
}
if (!emit1(JSOp::Pop)) {
// [stack] CTOR OBJ
return false;
}
}
continue;
}
if (propdef->isKind(ParseNodeKind::StaticClassBlock)) {
// Static class blocks are emitted as part of
// emitCreateMemberInitializers.
continue;
}
if (propdef->is<LexicalScopeNode>()) {
// Constructors are sometimes wrapped in LexicalScopeNodes. As we
// already handled emitting the constructor, skip it.
MOZ_ASSERT(
propdef->as<LexicalScopeNode>().scopeBody()->is<ClassMethod>());
continue;
}
// Handle __proto__: v specially because *only* this form, and no other
// involving "__proto__", performs [[Prototype]] mutation.
if (propdef->isKind(ParseNodeKind::MutateProto)) {
// [stack] OBJ
MOZ_ASSERT(type == ObjectLiteral);
if (!pe.prepareForProtoValue(propdef->pn_pos.begin)) {
// [stack] OBJ
return false;
}
if (!emitTree(propdef->as<UnaryNode>().kid())) {
// [stack] OBJ PROTO
return false;
}
if (!pe.emitMutateProto()) {
// [stack] OBJ
return false;
}
continue;
}
if (propdef->isKind(ParseNodeKind::Spread)) {
MOZ_ASSERT(type == ObjectLiteral);
// [stack] OBJ
if (!pe.prepareForSpreadOperand(propdef->pn_pos.begin)) {
// [stack] OBJ OBJ
return false;
}
if (!emitTree(propdef->as<UnaryNode>().kid())) {
// [stack] OBJ OBJ VAL
return false;
}
if (!pe.emitSpread()) {
// [stack] OBJ
return false;
}
continue;
}
BinaryNode* prop = &propdef->as<BinaryNode>();
ParseNode* key = prop->left();
AccessorType accessorType;
if (prop->is<ClassMethod>()) {
ClassMethod& method = prop->as<ClassMethod>();
accessorType = method.accessorType();
if (!method.isStatic() && key->isKind(ParseNodeKind::PrivateName) &&
accessorType != AccessorType::None) {
// Private non-static accessors are stamped onto instances from
// initializers; see emitCreateMemberInitializers.
continue;
}
} else if (prop->is<PropertyDefinition>()) {
accessorType = prop->as<PropertyDefinition>().accessorType();
} else {
accessorType = AccessorType::None;
}
auto emitValue = [this, &key, &prop, accessorType, &pe]() {
// [stack] CTOR? OBJ CTOR? KEY?
ParseNode* propVal = prop->right();
if (propVal->isDirectRHSAnonFunction()) {
// The following branches except for the last `else` clause emit the
// cases handled in NameResolver::resolveFun (see NameFunctions.cpp)
if (key->isKind(ParseNodeKind::ObjectPropertyName) ||
key->isKind(ParseNodeKind::PrivateName) ||
key->isKind(ParseNodeKind::StringExpr)) {
auto keyAtom = key->as<NameNode>().atom();
if (!emitAnonymousFunctionWithName(propVal, keyAtom)) {
// [stack] CTOR? OBJ CTOR? VAL
return false;
}
} else if (key->isKind(ParseNodeKind::NumberExpr)) {
MOZ_ASSERT(accessorType == AccessorType::None);
auto keyAtom = key->as<NumericLiteral>().toAtom(fc, parserAtoms());
if (!keyAtom) {
return false;
}
if (!emitAnonymousFunctionWithName(propVal, keyAtom)) {
// [stack] CTOR? OBJ CTOR? KEY VAL
return false;
}
} else if (key->isKind(ParseNodeKind::ComputedName) &&
(key->as<UnaryNode>().kid()->isKind(
ParseNodeKind::NumberExpr) ||
key->as<UnaryNode>().kid()->isKind(
ParseNodeKind::StringExpr)) &&
accessorType == AccessorType::None) {
ParseNode* keyKid = key->as<UnaryNode>().kid();
if (keyKid->isKind(ParseNodeKind::NumberExpr)) {
auto keyAtom =
keyKid->as<NumericLiteral>().toAtom(fc, parserAtoms());
if (!keyAtom) {
return false;
}
if (!emitAnonymousFunctionWithName(propVal, keyAtom)) {
// [stack] CTOR? OBJ CTOR? KEY VAL
return false;
}
} else {
MOZ_ASSERT(keyKid->isKind(ParseNodeKind::StringExpr));
auto keyAtom = keyKid->as<NameNode>().atom();
if (!emitAnonymousFunctionWithName(propVal, keyAtom)) {
// [stack] CTOR? OBJ CTOR? KEY VAL
return false;
}
}
} else {
// Either a proper computed property name or a synthetic computed
// property name for BigInt keys.
MOZ_ASSERT(key->isKind(ParseNodeKind::ComputedName));
FunctionPrefixKind prefix =
accessorType == AccessorType::None ? FunctionPrefixKind::None
: accessorType == AccessorType::Getter ? FunctionPrefixKind::Get
: FunctionPrefixKind::Set;
if (!emitAnonymousFunctionWithComputedName(propVal, prefix)) {
// [stack] CTOR? OBJ CTOR? KEY VAL
return false;
}
}
} else {
if (!emitTree(propVal)) {
// [stack] CTOR? OBJ CTOR? KEY? VAL
return false;
}
}
if (propVal->is<FunctionNode>() &&
propVal->as<FunctionNode>().funbox()->needsHomeObject()) {
if (!pe.emitInitHomeObject()) {
// [stack] CTOR? OBJ CTOR? KEY? FUN
return false;
}
}
#ifdef ENABLE_DECORATORS
if (prop->is<ClassMethod>()) {
ClassMethod& method = prop->as<ClassMethod>();
if (method.decorators() && !method.decorators()->empty()) {
DecoratorEmitter::Kind kind;
switch (method.accessorType()) {
case AccessorType::Getter:
kind = DecoratorEmitter::Getter;
break;
case AccessorType::Setter:
kind = DecoratorEmitter::Setter;
break;
case AccessorType::None:
kind = DecoratorEmitter::Method;
break;
}
if (!method.isStatic()) {
bool hasKeyOnStack = key->isKind(ParseNodeKind::NumberExpr) ||
key->isKind(ParseNodeKind::ComputedName);
if (!emitDupAt(hasKeyOnStack ? 4 : 3)) {
// [stack] ADDINIT OBJ KEY? VAL ADDINIT
return false;
}
} else {
// Note: Key will be present if this has a private name.
if (!emit1(JSOp::Undefined)) {
// [stack] CTOR OBJ CTOR KEY? VAL ADDINIT
return false;
}
}
if (!emit1(JSOp::Swap)) {
// [stack] ADDINIT CTOR? OBJ CTOR? KEY? ADDINIT VAL
return false;
}
// The decorators are applied to the current value on the stack,
// possibly replacing it.
DecoratorEmitter de(this);
if (!de.emitApplyDecoratorsToElementDefinition(
kind, key, method.decorators(), method.isStatic())) {
// [stack] ADDINIT CTOR? OBJ CTOR? KEY? ADDINIT VAL
return false;
}
if (!emit1(JSOp::Swap)) {
// [stack] ADDINIT CTOR? OBJ CTOR? KEY? VAL ADDINIT
return false;
}
if (!emitPopN(1)) {
// [stack] ADDINIT CTOR? OBJ CTOR? KEY? VAL
return false;
}
}
}
#endif
return true;
};
PropertyEmitter::Kind kind =
(type == ClassBody && propdef->as<ClassMethod>().isStatic())
? PropertyEmitter::Kind::Static
: PropertyEmitter::Kind::Prototype;
if (key->isKind(ParseNodeKind::ObjectPropertyName) ||
key->isKind(ParseNodeKind::StringExpr)) {
// [stack] CTOR? OBJ
auto keyAtom = key->as<NameNode>().atom();
// emitClass took care of constructor already.
if (type == ClassBody &&
keyAtom == TaggedParserAtomIndex::WellKnown::constructor() &&
!propdef->as<ClassMethod>().isStatic()) {
continue;
}
if (!pe.prepareForPropValue(propdef->pn_pos.begin, kind)) {
// [stack] CTOR? OBJ CTOR?
return false;
}
if (!emitValue()) {
// [stack] CTOR? OBJ CTOR? VAL
return false;
}
if (!pe.emitInit(accessorType, keyAtom)) {
// [stack] CTOR? OBJ
return false;
}
continue;
}
if (key->isKind(ParseNodeKind::NumberExpr)) {
// [stack] CTOR? OBJ
if (!pe.prepareForIndexPropKey(propdef->pn_pos.begin, kind)) {
// [stack] CTOR? OBJ CTOR?
return false;
}
if (!emitNumberOp(key->as<NumericLiteral>().value())) {
// [stack] CTOR? OBJ CTOR? KEY
return false;
}
if (!pe.prepareForIndexPropValue()) {
// [stack] CTOR? OBJ CTOR? KEY
return false;
}
if (!emitValue()) {
// [stack] CTOR? OBJ CTOR? KEY VAL
return false;
}
if (!pe.emitInitIndexOrComputed(accessorType)) {
// [stack] CTOR? OBJ
return false;
}
continue;
}
if (key->isKind(ParseNodeKind::ComputedName)) {
// Either a proper computed property name or a synthetic computed property
// name for BigInt keys.
// [stack] CTOR? OBJ
if (!pe.prepareForComputedPropKey(propdef->pn_pos.begin, kind)) {
// [stack] CTOR? OBJ CTOR?
return false;
}
if (!emitTree(key->as<UnaryNode>().kid())) {
// [stack] CTOR? OBJ CTOR? KEY
return false;
}
if (!pe.prepareForComputedPropValue()) {
// [stack] CTOR? OBJ CTOR? KEY
return false;
}
if (!emitValue()) {
// [stack] CTOR? OBJ CTOR? KEY VAL
return false;
}
if (!pe.emitInitIndexOrComputed(accessorType)) {
// [stack] CTOR? OBJ
return false;
}
continue;
}
MOZ_ASSERT(key->isKind(ParseNodeKind::PrivateName));
MOZ_ASSERT(type == ClassBody);
auto* privateName = &key->as<NameNode>();
if (kind == PropertyEmitter::Kind::Prototype) {
MOZ_ASSERT(accessorType == AccessorType::None);
if (!pe.prepareForPrivateMethod()) {
// [stack] CTOR OBJ
return false;
}
NameOpEmitter noe(this, privateName->atom(),
NameOpEmitter::Kind::SimpleAssignment);
// Ensure the NameOp emitter doesn't push an environment onto the stack,
// because that would change the stack location of the home object.
MOZ_ASSERT(noe.loc().kind() == NameLocation::Kind::FrameSlot ||
noe.loc().kind() == NameLocation::Kind::EnvironmentCoordinate);
if (!noe.prepareForRhs()) {
// [stack] CTOR OBJ
return false;
}
if (!emitValue()) {
// [stack] CTOR OBJ METHOD
return false;
}
if (!noe.emitAssignment()) {
// [stack] CTOR OBJ METHOD
return false;
}
if (!emit1(JSOp::Pop)) {
// [stack] CTOR OBJ
return false;
}
if (!pe.skipInit()) {
// [stack] CTOR OBJ
return false;
}
continue;
}
MOZ_ASSERT(kind == PropertyEmitter::Kind::Static);
// [stack] CTOR OBJ
if (!pe.prepareForPrivateStaticMethod(propdef->pn_pos.begin)) {
// [stack] CTOR OBJ CTOR
return false;
}
if (!emitGetPrivateName(privateName)) {
// [stack] CTOR OBJ CTOR KEY
return false;
}
if (!emitValue()) {
// [stack] CTOR OBJ CTOR KEY VAL
return false;
}
if (!pe.emitPrivateStaticMethod(accessorType)) {
// [stack] CTOR OBJ
return false;
}
if (privateName->privateNameKind() == PrivateNameKind::Setter) {
if (!emitDupAt(1)) {
// [stack] CTOR OBJ CTOR
return false;
}
if (!emitGetPrivateName(privateName)) {
// [stack] CTOR OBJ CTOR NAME
return false;
}
if (!emitAtomOp(JSOp::GetIntrinsic,
TaggedParserAtomIndex::WellKnown::NoPrivateGetter())) {
// [stack] CTOR OBJ CTOR NAME FUN
return false;
}
if (!emit1(JSOp::InitHiddenElemGetter)) {
// [stack] CTOR OBJ CTOR
return false;
}
if (!emit1(JSOp::Pop)) {
// [stack] CTOR OBJ
return false;
}
}
}
return true;
}
bool BytecodeEmitter::emitPropertyListObjLiteral(ListNode* obj, JSOp op,
bool useObjLiteralValues) {
ObjLiteralWriter writer;
#ifdef DEBUG
// In self-hosted JS, we check duplication only on debug build.
mozilla::Maybe<mozilla::HashSet<frontend::TaggedParserAtomIndex,
frontend::TaggedParserAtomIndexHasher>>
selfHostedPropNames;
if (emitterMode == BytecodeEmitter::SelfHosting) {
selfHostedPropNames.emplace();
}
#endif
if (op == JSOp::Object) {
writer.beginObject(op);
} else {
MOZ_ASSERT(op == JSOp::NewObject);
writer.beginShape(op);
}
for (ParseNode* propdef : obj->contents()) {
BinaryNode* prop = &propdef->as<BinaryNode>();
ParseNode* key = prop->left();
if (key->is<NameNode>()) {
if (emitterMode == BytecodeEmitter::SelfHosting) {
auto propName = key->as<NameNode>().atom();
#ifdef DEBUG
// Self-hosted JS shouldn't contain duplicate properties.
auto p = selfHostedPropNames->lookupForAdd(propName);
MOZ_ASSERT(!p);
if (!selfHostedPropNames->add(p, propName)) {
js::ReportOutOfMemory(fc);
return false;
}
#endif
writer.setPropNameNoDuplicateCheck(parserAtoms(), propName);
} else {
if (!writer.setPropName(parserAtoms(), key->as<NameNode>().atom())) {
return false;
}
}
} else {
double numValue = key->as<NumericLiteral>().value();
int32_t i = 0;
DebugOnly<bool> numIsInt =
NumberIsInt32(numValue, &i); // checked previously.
MOZ_ASSERT(numIsInt);
MOZ_ASSERT(
ObjLiteralWriter::arrayIndexInRange(i)); // checked previously.
// Ignore indexed properties if we're not storing property values, and
// rely on InitElem ops to define those. These properties will be either
// dense elements (not possible to represent in the literal's shape) or
// sparse elements (enumerated separately, so this doesn't affect property
// iteration order).
if (!useObjLiteralValues) {
continue;
}
writer.setPropIndex(i);
}
if (useObjLiteralValues) {
MOZ_ASSERT(op == JSOp::Object);
ParseNode* value = prop->right();
if (!emitObjLiteralValue(writer, value)) {
return false;
}
} else {
if (!writer.propWithUndefinedValue(fc)) {
return false;
}
}
}
GCThingIndex index;
if (!addObjLiteralData(writer, &index)) {
return false;
}
// JSOp::Object may only be used by (top-level) run-once scripts.
MOZ_ASSERT_IF(op == JSOp::Object,
sc->isTopLevelContext() && sc->treatAsRunOnce());
if (!emitGCIndexOp(op, index)) {
// [stack] OBJ
return false;
}
return true;
}
bool BytecodeEmitter::emitDestructuringRestExclusionSetObjLiteral(
ListNode* pattern) {
// Note: if we want to squeeze out a little more performance, we could switch
// to the `JSOp::Object` opcode, because the exclusion set object is never
// exposed to the user, so it's safe to bake the object into the bytecode.
constexpr JSOp op = JSOp::NewObject;
ObjLiteralWriter writer;
writer.beginShape(op);
for (ParseNode* member : pattern->contents()) {
if (member->isKind(ParseNodeKind::Spread)) {
MOZ_ASSERT(!member->pn_next, "unexpected trailing element after spread");
break;
}
TaggedParserAtomIndex atom;
if (member->isKind(ParseNodeKind::MutateProto)) {
atom = TaggedParserAtomIndex::WellKnown::proto_();
} else {
ParseNode* key = member->as<BinaryNode>().left();
atom = key->as<NameNode>().atom();
}
if (!writer.setPropName(parserAtoms(), atom)) {
return false;
}
if (!writer.propWithUndefinedValue(fc)) {
return false;
}
}
GCThingIndex index;
if (!addObjLiteralData(writer, &index)) {
return false;
}
if (!emitGCIndexOp(op, index)) {
// [stack] OBJ
return false;
}
return true;
}
bool BytecodeEmitter::emitObjLiteralArray(ListNode* array) {
MOZ_ASSERT(checkSingletonContext());
constexpr JSOp op = JSOp::Object;
ObjLiteralWriter writer;
writer.beginArray(op);
writer.beginDenseArrayElements();
for (ParseNode* elem : array->contents()) {
if (!emitObjLiteralValue(writer, elem)) {
return false;
}
}
GCThingIndex index;
if (!addObjLiteralData(writer, &index)) {
return false;
}
if (!emitGCIndexOp(op, index)) {
// [stack] OBJ
return false;
}
return true;
}
bool BytecodeEmitter::isRHSObjLiteralCompatible(ParseNode* value) {
return value->isKind(ParseNodeKind::NumberExpr) ||
value->isKind(ParseNodeKind::TrueExpr) ||
value->isKind(ParseNodeKind::FalseExpr) ||
value->isKind(ParseNodeKind::NullExpr) ||
value->isKind(ParseNodeKind::RawUndefinedExpr) ||
value->isKind(ParseNodeKind::StringExpr) ||
value->isKind(ParseNodeKind::TemplateStringExpr);
}
bool BytecodeEmitter::emitObjLiteralValue(ObjLiteralWriter& writer,
ParseNode* value) {
MOZ_ASSERT(isRHSObjLiteralCompatible(value));
if (value->isKind(ParseNodeKind::NumberExpr)) {
double numValue = value->as<NumericLiteral>().value();
int32_t i = 0;
js::Value v;
if (NumberIsInt32(numValue, &i)) {
v.setInt32(i);
} else {
v.setDouble(numValue);
}
if (!writer.propWithConstNumericValue(fc, v)) {
return false;
}
} else if (value->isKind(ParseNodeKind::TrueExpr)) {
if (!writer.propWithTrueValue(fc)) {
return false;
}
} else if (value->isKind(ParseNodeKind::FalseExpr)) {
if (!writer.propWithFalseValue(fc)) {
return false;
}
} else if (value->isKind(ParseNodeKind::NullExpr)) {
if (!writer.propWithNullValue(fc)) {
return false;
}
} else if (value->isKind(ParseNodeKind::RawUndefinedExpr)) {
if (!writer.propWithUndefinedValue(fc)) {
return false;
}
} else if (value->isKind(ParseNodeKind::StringExpr) ||
value->isKind(ParseNodeKind::TemplateStringExpr)) {
if (!writer.propWithAtomValue(fc, parserAtoms(),
value->as<NameNode>().atom())) {
return false;
}
} else {
MOZ_CRASH("Unexpected parse node");
}
return true;
}
static bool NeedsPrivateBrand(ParseNode* member) {
return member->is<ClassMethod>() &&
member->as<ClassMethod>().name().isKind(ParseNodeKind::PrivateName) &&
!member->as<ClassMethod>().isStatic();
}
#ifdef ENABLE_DECORATORS
static bool HasDecorators(ParseNode* member) {
return member->is<ClassMethod>() && member->as<ClassMethod>().decorators();
}
#endif
mozilla::Maybe<MemberInitializers> BytecodeEmitter::setupMemberInitializers(
ListNode* classMembers, FieldPlacement placement) {
bool isStatic = placement == FieldPlacement::Static;
size_t numFields = 0;
size_t numPrivateInitializers = 0;
bool hasPrivateBrand = false;
#ifdef ENABLE_DECORATORS
bool hasDecorators = false;
#endif
for (ParseNode* member : classMembers->contents()) {
if (NeedsFieldInitializer(member, isStatic)) {
numFields++;
} else if (NeedsAccessorInitializer(member, isStatic)) {
numPrivateInitializers++;
hasPrivateBrand = true;
} else if (NeedsPrivateBrand(member)) {
hasPrivateBrand = true;
}
#ifdef ENABLE_DECORATORS
if (!hasDecorators && HasDecorators(member)) {
hasDecorators = true;
}
#endif
}
// If there are more initializers than can be represented, return invalid.
if (numFields + numPrivateInitializers >
MemberInitializers::MaxInitializers) {
return Nothing();
}
return Some(MemberInitializers(hasPrivateBrand,
#ifdef ENABLE_DECORATORS
hasDecorators,
#endif
numFields + numPrivateInitializers));
}
// Purpose of .fieldKeys:
// Computed field names (`["x"] = 2;`) must be ran at class-evaluation time,
// not object construction time. The transformation to do so is roughly as
// follows:
//
// class C {
// [keyExpr] = valueExpr;
// }
// -->
// let .fieldKeys = [keyExpr];
// let .initializers = [
// () => {
// this[.fieldKeys[0]] = valueExpr;
// }
// ];
// class C {
// constructor() {
// .initializers[0]();
// }
// }
//
// BytecodeEmitter::emitCreateFieldKeys does `let .fieldKeys = [...];`
// BytecodeEmitter::emitPropertyList fills in the elements of the array.
// See GeneralParser::fieldInitializer for the `this[.fieldKeys[0]]` part.
bool BytecodeEmitter::emitCreateFieldKeys(ListNode* obj,
FieldPlacement placement) {
bool isStatic = placement == FieldPlacement::Static;
auto isFieldWithComputedName = [isStatic](ParseNode* propdef) {
return propdef->is<ClassField>() &&
propdef->as<ClassField>().isStatic() == isStatic &&
propdef->as<ClassField>().name().getKind() ==
ParseNodeKind::ComputedName;
};
size_t numFieldKeys = std::count_if(
obj->contents().begin(), obj->contents().end(), isFieldWithComputedName);
if (numFieldKeys == 0) {
return true;
}
auto fieldKeys =
isStatic ? TaggedParserAtomIndex::WellKnown::dot_staticFieldKeys_()
: TaggedParserAtomIndex::WellKnown::dot_fieldKeys_();
NameOpEmitter noe(this, fieldKeys, NameOpEmitter::Kind::Initialize);
if (!noe.prepareForRhs()) {
return false;
}
if (!emitUint32Operand(JSOp::NewArray, numFieldKeys)) {
// [stack] ARRAY
return false;
}
if (!noe.emitAssignment()) {
// [stack] ARRAY
return false;
}
if (!emit1(JSOp::Pop)) {
// [stack]
return false;
}
return true;
}
static bool HasInitializer(ParseNode* node, bool isStaticContext) {
return (node->is<ClassField>() &&
node->as<ClassField>().isStatic() == isStaticContext) ||
(isStaticContext && node->is<StaticClassBlock>());
}
static FunctionNode* GetInitializer(ParseNode* node, bool isStaticContext) {
MOZ_ASSERT(HasInitializer(node, isStaticContext));
MOZ_ASSERT_IF(!node->is<ClassField>(), isStaticContext);
return node->is<ClassField>() ? node->as<ClassField>().initializer()
: node->as<StaticClassBlock>().function();
}
static bool IsPrivateInstanceAccessor(const ClassMethod* classMethod) {
return !classMethod->isStatic() &&
classMethod->name().isKind(ParseNodeKind::PrivateName) &&
classMethod->accessorType() != AccessorType::None;
}
bool BytecodeEmitter::emitCreateMemberInitializers(ClassEmitter& ce,
ListNode* obj,
FieldPlacement placement
#ifdef ENABLE_DECORATORS
,
bool hasHeritage
#endif
) {
// FieldPlacement::Instance, hasHeritage == false
// [stack] HOME
//
// FieldPlacement::Instance, hasHeritage == true
// [stack] HOME HERIT
//
// FieldPlacement::Static
// [stack] CTOR HOME
#ifdef ENABLE_DECORATORS
MOZ_ASSERT_IF(placement == FieldPlacement::Static, !hasHeritage);
#endif
mozilla::Maybe<MemberInitializers> memberInitializers =
setupMemberInitializers(obj, placement);
if (!memberInitializers) {
ReportAllocationOverflow(fc);
return false;
}
size_t numInitializers = memberInitializers->numMemberInitializers;
if (numInitializers == 0) {
return true;
}
bool isStatic = placement == FieldPlacement::Static;
if (!ce.prepareForMemberInitializers(numInitializers, isStatic)) {
// [stack] HOME HERIT? ARR
// or:
// [stack] CTOR HOME ARR
return false;
}
// Private accessors could be used in the field initializers, so make sure
// accessor initializers appear earlier in the .initializers array so they
// run first. Static private methods are not initialized using initializers
// (emitPropertyList emits bytecode to stamp them onto the constructor), so
// skip this step if isStatic.
if (!isStatic) {
if (!emitPrivateMethodInitializers(ce, obj)) {
return false;
}
}
for (ParseNode* propdef : obj->contents()) {
if (!HasInitializer(propdef, isStatic)) {
continue;
}
FunctionNode* initializer = GetInitializer(propdef, isStatic);
if (!ce.prepareForMemberInitializer()) {
return false;
}
if (!emitTree(initializer)) {
// [stack] HOME HERIT? ARR LAMBDA
// or:
// [stack] CTOR HOME ARR LAMBDA
return false;
}
if (initializer->funbox()->needsHomeObject()) {
MOZ_ASSERT(initializer->funbox()->allowSuperProperty());
if (!ce.emitMemberInitializerHomeObject(isStatic)) {
// [stack] HOME HERIT? ARR LAMBDA
// or:
// [stack] CTOR HOME ARR LAMBDA
return false;
}
}
if (!ce.emitStoreMemberInitializer()) {
// [stack] HOME HERIT? ARR
// or:
// [stack] CTOR HOME ARR
return false;
}
}
#ifdef ENABLE_DECORATORS
// Index to use to append new initializers returned by decorators to the array
if (!emitNumberOp(numInitializers)) {
// [stack] HOME HERIT? ARR I
// or:
// [stack] CTOR HOME ARR I
return false;
}
for (ParseNode* propdef : obj->contents()) {
if (!propdef->is<ClassField>()) {
continue;
}
ClassField* field = &propdef->as<ClassField>();
if (field->isStatic() != isStatic) {
continue;
}
if (field->decorators() && !field->decorators()->empty()) {
DecoratorEmitter de(this);
if (!field->hasAccessor()) {
if (!emitDupAt((hasHeritage || isStatic) ? 4 : 3)) {
// [stack] ADDINIT HOME HERIT? ARR I ADDINIT
// or:
// [stack] ADDINIT CTOR HOME ARR I ADDINIT
return false;
}
if (!de.emitApplyDecoratorsToFieldDefinition(
&field->name(), field->decorators(), field->isStatic())) {
// [stack] HOME HERIT? ARR I ADDINIT INITS
// or:
// [stack] CTOR HOME ARR I ADDINIT INITS
return false;
}
if (!emit1(JSOp::Swap)) {
// [stack] HOME HERIT? ARR I INITS ADDINIT
// or:
// [stack] CTOR HOME ARR I INITS ADDINIT
return false;
}
if (!emitPopN(1)) {
// [stack] ADDINIT HOME HERIT? ARR I INITS
// or:
// [stack] ADDINIT CTOR HOME ARR I INITS
return false;
}
} else {
ClassMethod* accessorGetterNode = field->accessorGetterNode();
auto accessorGetterKeyAtom =
accessorGetterNode->left()->as<NameNode>().atom();
ClassMethod* accessorSetterNode = field->accessorSetterNode();
auto accessorSetterKeyAtom =
accessorSetterNode->left()->as<NameNode>().atom();
if (!IsPrivateInstanceAccessor(accessorGetterNode)) {
if (!emitTree(&accessorGetterNode->method())) {
// [stack] ADDINIT HOME HERIT? ARR I GET
// or:
// [stack] ADDINIT CTOR HOME ARR I GET
return false;
}
if (!emitTree(&accessorSetterNode->method())) {
// [stack] ADDINIT HOME HERIT? ARR I GET
// SET
// or:
// [stack] ADDINIT CTOR HOME ARR I GET SET
return false;
}
} else {
MOZ_ASSERT(IsPrivateInstanceAccessor(accessorSetterNode));
auto getAccessor = [this](
ClassMethod* classMethod,
TaggedParserAtomIndex& updatedAtom) -> bool {
// [stack]
// Synthesize a name for the lexical variable that will store the
// private method body.
TaggedParserAtomIndex name =
classMethod->name().as<NameNode>().atom();
AccessorType accessorType = classMethod->accessorType();
StringBuffer storedMethodName(fc);
if (!storedMethodName.append(parserAtoms(), name)) {
return false;
}
if (!storedMethodName.append(accessorType == AccessorType::Getter
? ".getter"
: ".setter")) {
return false;
}
updatedAtom = storedMethodName.finishParserAtom(parserAtoms(), fc);
if (!updatedAtom) {
return false;
}
return emitGetName(updatedAtom);
// [stack] ACCESSOR
};
if (!getAccessor(accessorGetterNode, accessorGetterKeyAtom)) {
// [stack] ADDINIT HOME HERIT? ARR I GET
// or:
// [stack] ADDINIT CTOR HOME ARR I GET
return false;
};
if (!getAccessor(accessorSetterNode, accessorSetterKeyAtom)) {
// [stack] ADDINIT HOME HERIT? ARR I GET SET
// or:
// [stack] ADDINIT CTOR HOME ARR I GET SET
return false;
};
}
if (!emitDupAt((hasHeritage || isStatic) ? 6 : 5)) {
// [stack] ADDINIT HOME HERIT? ARR I GET SET ADDINIT
// or:
// [stack] ADDINIT CTOR HOME ARR I GET SET ADDINIT
return false;
}
if (!emitUnpickN(2)) {
// [stack] ADDINIT HOME HERIT? ARR I ADDINIT GET SET
// or:
// [stack] ADDINIT CTOR HOME ARR I ADDINIT GET SET
return false;
}
if (!de.emitApplyDecoratorsToAccessorDefinition(
&field->name(), field->decorators(), field->isStatic())) {
// [stack] ADDINIT HOME HERIT? ARR I ADDINIT GET SET INITS
// or:
// [stack] ADDINIT CTOR HOME ARR I ADDINIT GET SET INITS
return false;
}
if (!emitPickN(3)) {
// [stack] HOME HERIT? ARR I GET SET INITS ADDINIT
// or:
// [stack] CTOR HOME ARR I GET SET INITS ADDINIT
return false;
}
if (!emitPopN(1)) {
// [stack] ADDINIT HOME HERIT? ARR I GET SET INITS
// or:
// [stack] ADDINIT CTOR HOME ARR I GET SET INITS
return false;
}
if (!emitUnpickN(2)) {
// [stack] ADDINIT HOME HERIT? ARR I INITS GET SET
// or:
// [stack] ADDINIT CTOR HOME ARR I INITS GET SET
return false;
}
if (!IsPrivateInstanceAccessor(accessorGetterNode)) {
if (!isStatic) {
if (!emitDupAt(hasHeritage ? 6 : 5)) {
// [stack] ADDINIT HOME HERIT? ARR I INITS GET SET HOME
return false;
}
} else {
if (!emitDupAt(6)) {
// [stack] ADDINIT CTOR HOME ARR I INITS GET SET CTOR
return false;
}
if (!emitDupAt(6)) {
// [stack] ADDINIT CTOR HOME ARR I INITS GET SET CTOR HOME
return false;
}
}
PropertyEmitter::Kind kind = field->isStatic()
? PropertyEmitter::Kind::Static
: PropertyEmitter::Kind::Prototype;
if (!accessorGetterNode->name().isKind(ParseNodeKind::PrivateName)) {
MOZ_ASSERT(
!accessorSetterNode->name().isKind(ParseNodeKind::PrivateName));
if (!ce.prepareForPropValue(propdef->pn_pos.begin, kind)) {
// [stack] ADDINIT HOME HERIT? ARR I INITS GET SET HOME
// or:
// [stack] ADDINIT CTOR HOME ARR I INITS GET SET CTOR HOME CTOR
return false;
}
if (!emitPickN(isStatic ? 3 : 1)) {
// [stack] ADDINIT HOME HERIT? ARR I INITS GET HOME SET
// or:
// [stack] ADDINIT CTOR HOME ARR I INITS GET CTOR HOME CTOR SET
return false;
}
if (!ce.emitInit(AccessorType::Setter, accessorSetterKeyAtom)) {
// [stack] ADDINIT HOME HERIT? ARR I INITS GET HOME
// or:
// [stack] ADDINIT CTOR HOME ARR I INITS GET CTOR HOME
return false;
}
if (!ce.prepareForPropValue(propdef->pn_pos.begin, kind)) {
// [stack] ADDINIT HOME HERIT? ARR I INITS GET HOME
// or:
// [stack] ADDINIT CTOR HOME ARR I INITS GET CTOR HOME CTOR
return false;
}
if (!emitPickN(isStatic ? 3 : 1)) {
// [stack] ADDINIT HOME HERIT? ARR I INITS HOME GET
// or:
// [stack] ADDINIT CTOR HOME ARR I INITS CTOR HOME CTOR GET
return false;
}
if (!ce.emitInit(AccessorType::Getter, accessorGetterKeyAtom)) {
// [stack] ADDINIT HOME HERIT? ARR I INITS HOME
// or:
// [stack] ADDINIT CTOR HOME ARR I INITS CTOR HOME
return false;
}
} else {
MOZ_ASSERT(isStatic);
// The getter and setter share the same name.
if (!emitNewPrivateName(accessorSetterKeyAtom,
accessorSetterKeyAtom)) {
return false;
}
if (!ce.prepareForPrivateStaticMethod(propdef->pn_pos.begin)) {
// [stack] ADDINIT CTOR HOME ARR I INITS GET SET CTOR HOME CTOR
return false;
}
if (!emitGetPrivateName(
&accessorSetterNode->name().as<NameNode>())) {
// [stack] ADDINIT CTOR HOME ARR I INITS GET SET CTOR HOME CTOR
// KEY
return false;
}
if (!emitPickN(4)) {
// [stack] ADDINIT CTOR HOME ARR I INITS GET CTOR HOME CTOR KEY
// SET
return false;
}
if (!ce.emitPrivateStaticMethod(AccessorType::Setter)) {
// [stack] ADDINIT CTOR HOME ARR I INITS GET CTOR HOME
return false;
}
if (!ce.prepareForPrivateStaticMethod(propdef->pn_pos.begin)) {
// [stack] ADDINIT CTOR HOME ARR I INITS GET CTOR HOME CTOR
return false;
}
if (!emitGetPrivateName(
&accessorGetterNode->name().as<NameNode>())) {
// [stack] ADDINIT CTOR HOME ARR I INITS GET CTOR HOME CTOR KEY
return false;
}
if (!emitPickN(4)) {
// [stack] ADDINIT CTOR HOME ARR I INITS CTOR HOME CTOR KEY GET
return false;
}
if (!ce.emitPrivateStaticMethod(AccessorType::Getter)) {
// [stack] ADDINIT CTOR HOME ARR I INITS CTOR HOME
return false;
}
}
if (!isStatic) {
if (!emitPopN(1)) {
// [stack] ADDINIT HOME HERIT? ARR I INITS
return false;
}
} else {
if (!emitPopN(2)) {
// [stack] ADDINIT CTOR HOME ARR I INITS
return false;
}
}
} else {
MOZ_ASSERT(IsPrivateInstanceAccessor(accessorSetterNode));
if (!emitLexicalInitialization(accessorSetterKeyAtom)) {
// [stack] ADDINIT HOME HERIT? ARR I INITS GET SET
// or:
// [stack] ADDINIT CTOR HOME ARR I INITS GET SET
return false;
}
if (!emitPopN(1)) {
// [stack] ADDINIT HOME HERIT? ARR I INITS GET
// or:
// [stack] ADDINIT CTOR HOME ARR I INITS GET
return false;
}
if (!emitLexicalInitialization(accessorGetterKeyAtom)) {
// [stack] ADDINIT HOME HERIT? ARR I INITS GET
// or:
// [stack] ADDINIT CTOR HOME ARR I INITS GET
return false;
}
if (!emitPopN(1)) {
// [stack] ADDINIT HOME HERIT? ARR I INITS
// or:
// [stack] ADDINIT CTOR HOME ARR I INITS
return false;
}
}
}
if (!emit1(JSOp::InitElemInc)) {
// [stack] ADDINIT HOME HERIT? ARR I
// or:
// [stack] ADDINIT CTOR HOME ARR I
return false;
}
}
}
// Pop I
if (!emitPopN(1)) {
// [stack] ADDINIT HOME HERIT? ARR
// or:
// [stack] ADDINIT CTOR HOME ARR
return false;
}
#endif
if (!ce.emitMemberInitializersEnd()) {
// [stack] ADDINIT HOME HERIT?
// or:
// [stack] ADDINIT CTOR HOME
return false;
}
return true;
}
bool BytecodeEmitter::emitPrivateMethodInitializers(ClassEmitter& ce,
ListNode* obj) {
for (ParseNode* propdef : obj->contents()) {
if (!propdef->is<ClassMethod>()) {
continue;
}
auto* classMethod = &propdef->as<ClassMethod>();
// Skip over anything which isn't a private instance accessor.
if (!IsPrivateInstanceAccessor(classMethod)) {
continue;
}
if (!ce.prepareForMemberInitializer()) {
// [stack] HOMEOBJ HERITAGE? ARRAY
// or:
// [stack] CTOR HOMEOBJ ARRAY
return false;
}
// Synthesize a name for the lexical variable that will store the
// private method body.
TaggedParserAtomIndex name = classMethod->name().as<NameNode>().atom();
AccessorType accessorType = classMethod->accessorType();
StringBuffer storedMethodName(fc);
if (!storedMethodName.append(parserAtoms(), name)) {
return false;
}
if (!storedMethodName.append(
accessorType == AccessorType::Getter ? ".getter" : ".setter")) {
return false;
}
auto storedMethodAtom =
storedMethodName.finishParserAtom(parserAtoms(), fc);
// Emit the private method body and store it as a lexical var.
if (!emitFunction(&classMethod->method())) {
// [stack] HOMEOBJ HERITAGE? ARRAY METHOD
// or:
// [stack] CTOR HOMEOBJ ARRAY METHOD
return false;
}
// The private method body needs to access the home object,
// and the CE knows where that is on the stack.
if (classMethod->method().funbox()->needsHomeObject()) {
if (!ce.emitMemberInitializerHomeObject(false)) {
// [stack] HOMEOBJ HERITAGE? ARRAY METHOD
// or:
// [stack] CTOR HOMEOBJ ARRAY METHOD
return false;
}
}
if (!emitLexicalInitialization(storedMethodAtom)) {
// [stack] HOMEOBJ HERITAGE? ARRAY METHOD
// or:
// [stack] CTOR HOMEOBJ ARRAY METHOD
return false;
}
if (!emit1(JSOp::Pop)) {
// [stack] HOMEOBJ HERITAGE? ARRAY
// or:
// [stack] CTOR HOMEOBJ ARRAY
return false;
}
if (!emitPrivateMethodInitializer(classMethod, storedMethodAtom)) {
// [stack] HOMEOBJ HERITAGE? ARRAY
// or:
// [stack] CTOR HOMEOBJ ARRAY
return false;
}
// Store the emitted initializer function into the .initializers array.
if (!ce.emitStoreMemberInitializer()) {
// [stack] HOMEOBJ HERITAGE? ARRAY
// or:
// [stack] CTOR HOMEOBJ ARRAY
return false;
}
}
return true;
}
bool BytecodeEmitter::emitPrivateMethodInitializer(
ClassMethod* classMethod, TaggedParserAtomIndex storedMethodAtom) {
MOZ_ASSERT(IsPrivateInstanceAccessor(classMethod));
auto* name = &classMethod->name().as<NameNode>();
// Emit the synthesized initializer function.
FunctionNode* funNode = classMethod->initializerIfPrivate();
MOZ_ASSERT(funNode);
FunctionBox* funbox = funNode->funbox();
FunctionEmitter fe(this, funbox, funNode->syntaxKind(),
FunctionEmitter::IsHoisted::No);
if (!fe.prepareForNonLazy()) {
// [stack]
return false;
}
BytecodeEmitter bce2(this, funbox);
if (!bce2.init(funNode->pn_pos)) {
return false;
}
ParamsBodyNode* paramsBody = funNode->body();
FunctionScriptEmitter fse(&bce2, funbox, Nothing(), Nothing());
if (!fse.prepareForParameters()) {
// [stack]
return false;
}
if (!bce2.emitFunctionFormalParameters(paramsBody)) {
// [stack]
return false;
}
if (!fse.prepareForBody()) {
// [stack]
return false;
}
if (!bce2.emit1(JSOp::FunctionThis)) {
// [stack] THIS
return false;
}
if (!bce2.emitGetPrivateName(name)) {
// [stack] THIS NAME
return false;
}
if (!bce2.emitGetName(storedMethodAtom)) {
// [stack] THIS NAME METHOD
return false;
}
switch (name->privateNameKind()) {
case PrivateNameKind::Setter:
if (!bce2.emit1(JSOp::InitHiddenElemSetter)) {
// [stack] THIS
return false;
}
if (!bce2.emitGetPrivateName(name)) {
// [stack] THIS NAME
return false;
}
if (!bce2.emitAtomOp(
JSOp::GetIntrinsic,
TaggedParserAtomIndex::WellKnown::NoPrivateGetter())) {
// [stack] THIS NAME FUN
return false;
}
if (!bce2.emit1(JSOp::InitHiddenElemGetter)) {
// [stack] THIS
return false;
}
break;
case PrivateNameKind::Getter:
case PrivateNameKind::GetterSetter:
if (classMethod->accessorType() == AccessorType::Getter) {
if (!bce2.emit1(JSOp::InitHiddenElemGetter)) {
// [stack] THIS
return false;
}
} else {
if (!bce2.emit1(JSOp::InitHiddenElemSetter)) {
// [stack] THIS
return false;
}
}
break;
default:
MOZ_CRASH("Invalid op");
}
// Pop remaining THIS.
if (!bce2.emit1(JSOp::Pop)) {
// [stack]
return false;
}
if (!fse.emitEndBody()) {
// [stack]
return false;
}
if (!fse.intoStencil()) {
return false;
}
if (!fe.emitNonLazyEnd()) {
// [stack] HOMEOBJ HERITAGE? ARRAY FUN
// or:
// [stack] CTOR HOMEOBJ ARRAY FUN
return false;
}
return true;
}
const MemberInitializers& BytecodeEmitter::findMemberInitializersForCall() {
for (BytecodeEmitter* current = this; current; current = current->parent) {
if (current->sc->isFunctionBox()) {
FunctionBox* funbox = current->sc->asFunctionBox();
if (funbox->isArrow()) {
continue;
}
// If we found a non-arrow / non-constructor we were never allowed to
// expect fields in the first place.
MOZ_RELEASE_ASSERT(funbox->isClassConstructor());
return funbox->useMemberInitializers() ? funbox->memberInitializers()
: MemberInitializers::Empty();
}
}
MOZ_RELEASE_ASSERT(compilationState.scopeContext.memberInitializers);
return *compilationState.scopeContext.memberInitializers;
}
bool BytecodeEmitter::emitInitializeInstanceMembers(
bool isDerivedClassConstructor) {
const MemberInitializers& memberInitializers =
findMemberInitializersForCall();
MOZ_ASSERT(memberInitializers.valid);
if (memberInitializers.hasPrivateBrand) {
// This is guaranteed to run after super(), so we don't need TDZ checks.
if (!emitGetName(TaggedParserAtomIndex::WellKnown::dot_this_())) {
// [stack] THIS
return false;
}
if (!emitGetName(TaggedParserAtomIndex::WellKnown::dot_privateBrand_())) {
// [stack] THIS BRAND
return false;
}
if (isDerivedClassConstructor) {
if (!emitCheckPrivateField(ThrowCondition::ThrowHas,
ThrowMsgKind::PrivateBrandDoubleInit)) {
// [stack] THIS BRAND BOOL
return false;
}
if (!emit1(JSOp::Pop)) {
// [stack] THIS BRAND
return false;
}
}
if (!emit1(JSOp::Null)) {
// [stack] THIS BRAND NULL
return false;
}
if (!emit1(JSOp::InitHiddenElem)) {
// [stack] THIS
return false;
}
if (!emit1(JSOp::Pop)) {
// [stack]
return false;
}
}
size_t numInitializers = memberInitializers.numMemberInitializers;
if (numInitializers > 0) {
if (!emitGetName(TaggedParserAtomIndex::WellKnown::dot_initializers_())) {
// [stack] ARRAY
return false;
}
for (size_t index = 0; index < numInitializers; index++) {
if (index < numInitializers - 1) {
// We Dup to keep the array around (it is consumed in the bytecode
// below) for next iterations of this loop, except for the last
// iteration, which avoids an extra Pop at the end of the loop.
if (!emit1(JSOp::Dup)) {
// [stack] ARRAY ARRAY
return false;
}
}
if (!emitNumberOp(index)) {
// [stack] ARRAY? ARRAY INDEX
return false;
}
if (!emit1(JSOp::GetElem)) {
// [stack] ARRAY? FUNC
return false;
}
// This is guaranteed to run after super(), so we don't need TDZ checks.
if (!emitGetName(TaggedParserAtomIndex::WellKnown::dot_this_())) {
// [stack] ARRAY? FUNC THIS
return false;
}
// Callee is always internal function.
if (!emitCall(JSOp::CallIgnoresRv, 0)) {
// [stack] ARRAY? RVAL
return false;
}
if (!emit1(JSOp::Pop)) {
// [stack] ARRAY?
return false;
}
}
#ifdef ENABLE_DECORATORS
if (memberInitializers.hasDecorators) {
// Decorators Proposal
// 4. For each element e of elements, do
// 4.a. If elementRecord.[[Kind]] is field or accessor, then
// 4.a.i. Perform ? InitializeFieldOrAccessor(O, elementRecord).
//
// initialization logic in two steps. The pre-decorator initialization
// code runs, stores the initial value, and then we retrieve it here and
// apply the initializers added by decorators. We should unify these two
// steps.
if (!emitGetName(TaggedParserAtomIndex::WellKnown::dot_initializers_())) {
// [stack] ARRAY
return false;
}
if (!emit1(JSOp::Dup)) {
// [stack] ARRAY ARRAY
return false;
}
if (!emitAtomOp(JSOp::GetProp,
TaggedParserAtomIndex::WellKnown::length())) {
// [stack] ARRAY LENGTH
return false;
}
if (!emitNumberOp(static_cast<double>(numInitializers))) {
// [stack] ARRAY LENGTH INDEX
return false;
}
InternalWhileEmitter wh(this);
// At this point, we have no context to determine offsets in the
// code for this while statement. Ideally, it would correspond to
// the field we're initializing.
if (!wh.emitCond()) {
// [stack] ARRAY LENGTH INDEX
return false;
}
if (!emit1(JSOp::Dup)) {
// [stack] ARRAY LENGTH INDEX INDEX
return false;
}
if (!emitDupAt(2)) {
// [stack] ARRAY LENGTH INDEX INDEX LENGTH
return false;
}
if (!emit1(JSOp::Lt)) {
// [stack] ARRAY LENGTH INDEX BOOL
return false;
}
if (!wh.emitBody()) {
// [stack] ARRAY LENGTH INDEX
return false;
}
if (!emitDupAt(2)) {
// [stack] ARRAY LENGTH INDEX ARRAY
return false;
}
if (!emitDupAt(1)) {
// [stack] ARRAY LENGTH INDEX ARRAY INDEX
return false;
}
// Retrieve initializers for this field
if (!emit1(JSOp::GetElem)) {
// [stack] ARRAY LENGTH INDEX INITIALIZERS
return false;
}
// This is guaranteed to run after super(), so we don't need TDZ checks.
if (!emitGetName(TaggedParserAtomIndex::WellKnown::dot_this_())) {
// [stack] ARRAY LENGTH INDEX INITIALIZERS THIS
return false;
}
if (!emit1(JSOp::Swap)) {
// [stack] ARRAY LENGTH INDEX THIS INITIALIZERS
return false;
}
DecoratorEmitter de(this);
if (!de.emitInitializeFieldOrAccessor()) {
// [stack] ARRAY LENGTH INDEX
return false;
}
if (!emit1(JSOp::Inc)) {
// [stack] ARRAY LENGTH INDEX
return false;
}
if (!wh.emitEnd()) {
// [stack] ARRAY LENGTH INDEX
return false;
}
if (!emitPopN(3)) {
// [stack]
return false;
}
// 5. Return unused.
if (!de.emitCallExtraInitializers(TaggedParserAtomIndex::WellKnown::
dot_instanceExtraInitializers_())) {
return false;
}
}
#endif
}
return true;
}
bool BytecodeEmitter::emitInitializeStaticFields(ListNode* classMembers) {
auto isStaticField = [](ParseNode* propdef) {
return HasInitializer(propdef, true);
};
size_t numFields =
std::count_if(classMembers->contents().begin(),
classMembers->contents().end(), isStaticField);
if (numFields == 0) {
return true;
}
if (!emitGetName(
TaggedParserAtomIndex::WellKnown::dot_staticInitializers_())) {
// [stack] CTOR ARRAY
return false;
}
for (size_t fieldIndex = 0; fieldIndex < numFields; fieldIndex++) {
bool hasNext = fieldIndex < numFields - 1;
if (hasNext) {
// We Dup to keep the array around (it is consumed in the bytecode below)
// for next iterations of this loop, except for the last iteration, which
// avoids an extra Pop at the end of the loop.
if (!emit1(JSOp::Dup)) {
// [stack] CTOR ARRAY ARRAY
return false;
}
}
if (!emitNumberOp(fieldIndex)) {
// [stack] CTOR ARRAY? ARRAY INDEX
return false;
}
if (!emit1(JSOp::GetElem)) {
// [stack] CTOR ARRAY? FUNC
return false;
}
if (!emitDupAt(1 + hasNext)) {
// [stack] CTOR ARRAY? FUNC CTOR
return false;
}
// Callee is always internal function.
if (!emitCall(JSOp::CallIgnoresRv, 0)) {
// [stack] CTOR ARRAY? RVAL
return false;
}
if (!emit1(JSOp::Pop)) {
// [stack] CTOR ARRAY?
return false;
}
}
#ifdef ENABLE_DECORATORS
// Decorators Proposal
// 4. For each element e of elements, do
// 4.a. If elementRecord.[[Kind]] is field or accessor, then
// 4.a.i. Perform ? InitializeFieldOrAccessor(O, elementRecord).
//
// logic in two steps. The pre-decorator initialization code runs, stores
// the initial value, and then we retrieve it here and apply the
// initializers added by decorators. We should unify these two steps.
if (!emitGetName(
TaggedParserAtomIndex::WellKnown::dot_staticInitializers_())) {
// [stack] CTOR ARRAY
return false;
}
if (!emit1(JSOp::Dup)) {
// [stack] CTOR ARRAY ARRAY
return false;
}
if (!emitAtomOp(JSOp::GetProp, TaggedParserAtomIndex::WellKnown::length())) {
// [stack] CTOR ARRAY LENGTH
return false;
}
if (!emitNumberOp(static_cast<double>(numFields))) {
// [stack] CTOR ARRAY LENGTH INDEX
return false;
}
InternalWhileEmitter wh(this);
// At this point, we have no context to determine offsets in the
// code for this while statement. Ideally, it would correspond to
// the field we're initializing.
if (!wh.emitCond()) {
// [stack] CTOR ARRAY LENGTH INDEX
return false;
}
if (!emit1(JSOp::Dup)) {
// [stack] CTOR ARRAY LENGTH INDEX INDEX
return false;
}
if (!emitDupAt(2)) {
// [stack] CTOR ARRAY LENGTH INDEX INDEX LENGTH
return false;
}
if (!emit1(JSOp::Lt)) {
// [stack] CTOR ARRAY LENGTH INDEX BOOL
return false;
}
if (!wh.emitBody()) {
// [stack] CTOR ARRAY LENGTH INDEX
return false;
}
if (!emitDupAt(2)) {
// [stack] CTOR ARRAY LENGTH INDEX ARRAY
return false;
}
if (!emitDupAt(1)) {
// [stack] CTOR ARRAY LENGTH INDEX ARRAY INDEX
return false;
}
// Retrieve initializers for this field
if (!emit1(JSOp::GetElem)) {
// [stack] CTOR ARRAY LENGTH INDEX INITIALIZERS
return false;
}
if (!emitDupAt(4)) {
// [stack] CTOR ARRAY LENGTH INDEX INITIALIZERS CTOR
return false;
}
if (!emit1(JSOp::Swap)) {
// [stack] CTOR ARRAY LENGTH INDEX CTOR INITIALIZERS
return false;
}
DecoratorEmitter de(this);
if (!de.emitInitializeFieldOrAccessor()) {
// [stack] CTOR ARRAY LENGTH INDEX
return false;
}
if (!emit1(JSOp::Inc)) {
// [stack] CTOR ARRAY LENGTH INDEX
return false;
}
if (!wh.emitEnd()) {
// [stack] CTOR ARRAY LENGTH INDEX
return false;
}
if (!emitPopN(3)) {
// [stack] CTOR
return false;
}
// 5. Return unused.
#endif
// Overwrite |.staticInitializers| and |.staticFieldKeys| with undefined to
// avoid keeping the arrays alive indefinitely.
auto clearStaticFieldSlot = [&](TaggedParserAtomIndex name) {
NameOpEmitter noe(this, name, NameOpEmitter::Kind::SimpleAssignment);
if (!noe.prepareForRhs()) {
// [stack] ENV? VAL?
return false;
}
if (!emit1(JSOp::Undefined)) {
// [stack] ENV? VAL? UNDEFINED
return false;
}
if (!noe.emitAssignment()) {
// [stack] VAL
return false;
}
if (!emit1(JSOp::Pop)) {
// [stack]
return false;
}
return true;
};
if (!clearStaticFieldSlot(
TaggedParserAtomIndex::WellKnown::dot_staticInitializers_())) {
return false;
}
auto isStaticFieldWithComputedName = [](ParseNode* propdef) {
return propdef->is<ClassField>() && propdef->as<ClassField>().isStatic() &&
propdef->as<ClassField>().name().getKind() ==
ParseNodeKind::ComputedName;
};
if (std::any_of(classMembers->contents().begin(),
classMembers->contents().end(),
isStaticFieldWithComputedName)) {
if (!clearStaticFieldSlot(
TaggedParserAtomIndex::WellKnown::dot_staticFieldKeys_())) {
return false;
}
}
return true;
}
// Using MOZ_NEVER_INLINE in here is a workaround for llvm.org/pr14047. See
// the comment on emitSwitch.
MOZ_NEVER_INLINE bool BytecodeEmitter::emitObject(ListNode* objNode) {
// Note: this method uses the ObjLiteralWriter and emits ObjLiteralStencil
// objects into the GCThingList, which will evaluate them into real GC objects
// or shapes during JSScript::fullyInitFromEmitter. Eventually we want
// JSOp::Object to be a real opcode, but for now, performance constraints
// limit us to evaluating object literals at the end of parse, when we're
// allowed to allocate GC things.
//
// There are four cases here, in descending order of preference:
//
// 1. The list of property names is "normal" and constant (no computed
// values, no integer indices), the values are all simple constants
// (numbers, booleans, strings), *and* this occurs in a run-once
// (singleton) context. In this case, we can emit ObjLiteral
// instructions to build an object with values, and the object will be
// attached to a JSOp::Object opcode, whose semantics are for the backend
// to simply steal the object from the script.
//
// 2. The list of property names is "normal" and constant as above, *and* this
// occurs in a run-once (singleton) context, but some values are complex
// (computed expressions, sub-objects, functions, etc.). In this case, we
// can still use JSOp::Object (because singleton context), but the object
// has |undefined| property values and InitProp ops are emitted to set the
// values.
//
// 3. The list of property names is "normal" and constant as above, but this
// occurs in a non-run-once (non-singleton) context. In this case, we can
// use the ObjLiteral functionality to describe an *empty* object (all
// values left undefined) with the right fields, which will become a
// JSOp::NewObject opcode using the object's shape to speed up the creation
// of the object each time it executes. The emitted bytecode still needs
// InitProp ops to set the values in this case.
//
// 4. Any other case. As a fallback, we use NewInit to create a new, empty
// object (i.e., `{}`) and then emit bytecode to initialize its properties
// one-by-one.
bool useObjLiteral = false;
bool useObjLiteralValues = false;
isPropertyListObjLiteralCompatible(objNode, &useObjLiteralValues,
&useObjLiteral);
// [stack]
//
ObjectEmitter oe(this);
if (useObjLiteral) {
bool singleton = checkSingletonContext() &&
!objNode->hasNonConstInitializer() && objNode->head();
JSOp op;
if (singleton) {
// Case 1 or 2.
op = JSOp::Object;
} else {
// Case 3.
useObjLiteralValues = false;
op = JSOp::NewObject;
}
// Use an ObjLiteral op. This will record ObjLiteral insns in the
// objLiteralWriter's buffer and add a fixup to the list of ObjLiteral
// fixups so that at GC-publish time at the end of parse, the full object
// (case 1 or 2) or shape (case 3) can be allocated and the bytecode can be
// patched to refer to it.
if (!emitPropertyListObjLiteral(objNode, op, useObjLiteralValues)) {
// [stack] OBJ
return false;
}
// Put the ObjectEmitter in the right state. This tells it that there will
// already be an object on the stack as a result of the (eventual)
// NewObject or Object op, and prepares it to emit values if needed.
if (!oe.emitObjectWithTemplateOnStack()) {
// [stack] OBJ
return false;
}
if (!useObjLiteralValues) {
// Case 2 or 3 above: we still need to emit bytecode to fill in the
// object's property values.
if (!emitPropertyList(objNode, oe, ObjectLiteral)) {
// [stack] OBJ
return false;
}
}
} else {
// Case 4 above: no ObjLiteral use, just bytecode to build the object from
// scratch.
if (!oe.emitObject(objNode->count())) {
// [stack] OBJ
return false;
}
if (!emitPropertyList(objNode, oe, ObjectLiteral)) {
// [stack] OBJ
return false;
}
}
if (!oe.emitEnd()) {
// [stack] OBJ
return false;
}
return true;
}
bool BytecodeEmitter::emitArrayLiteral(ListNode* array) {
// Emit JSOp::Object if the array consists entirely of primitive values and we
// are in a singleton context.
if (checkSingletonContext() && !array->hasNonConstInitializer() &&
!array->empty() && isArrayObjLiteralCompatible(array)) {
return emitObjLiteralArray(array);
}
return emitArray(array);
}
bool BytecodeEmitter::emitArray(ListNode* array) {
/*
* Emit code for [a, b, c] that is equivalent to constructing a new
* array and in source order evaluating each element value and adding
* it to the array, without invoking latent setters. We use the
* JSOp::NewInit and JSOp::InitElemArray bytecodes to ignore setters and
* to avoid dup'ing and popping the array as each element is added, as
* JSOp::SetElem/JSOp::SetProp would do.
*/
uint32_t nspread = 0;
for (ParseNode* elem : array->contents()) {
if (elem->isKind(ParseNodeKind::Spread)) {
nspread++;
}
}
// Array literal's length is limited to NELEMENTS_LIMIT in parser.
static_assert(NativeObject::MAX_DENSE_ELEMENTS_COUNT <= INT32_MAX,
"array literals' maximum length must not exceed limits "
"required by BaselineCompiler::emit_NewArray, "
"BaselineCompiler::emit_InitElemArray, "
"and DoSetElemFallback's handling of JSOp::InitElemArray");
uint32_t count = array->count();
MOZ_ASSERT(count >= nspread);
MOZ_ASSERT(count <= NativeObject::MAX_DENSE_ELEMENTS_COUNT,
"the parser must throw an error if the array exceeds maximum "
"length");
// For arrays with spread, this is a very pessimistic allocation, the
// minimum possible final size.
if (!emitUint32Operand(JSOp::NewArray, count - nspread)) {
// [stack] ARRAY
return false;
}
uint32_t index = 0;
bool afterSpread = false;
for (ParseNode* elem : array->contents()) {
if (elem->isKind(ParseNodeKind::Spread)) {
if (!afterSpread) {
afterSpread = true;
if (!emitNumberOp(index)) {
// [stack] ARRAY INDEX
return false;
}
}
ParseNode* expr = elem->as<UnaryNode>().kid();
SelfHostedIter selfHostedIter = getSelfHostedIterFor(expr);
if (!updateSourceCoordNotes(elem->pn_pos.begin)) {
return false;
}
if (!emitIterable(expr, selfHostedIter)) {
// [stack] ARRAY INDEX ITERABLE
return false;
}
if (!emitIterator(selfHostedIter)) {
// [stack] ARRAY INDEX NEXT ITER
return false;
}
if (!emit2(JSOp::Pick, 3)) {
// [stack] INDEX NEXT ITER ARRAY
return false;
}
if (!emit2(JSOp::Pick, 3)) {
// [stack] NEXT ITER ARRAY INDEX
return false;
}
if (!emitSpread(selfHostedIter)) {
// [stack] ARRAY INDEX
return false;
}
} else {
if (!updateSourceCoordNotesIfNonLiteral(elem)) {
return false;
}
if (elem->isKind(ParseNodeKind::Elision)) {
if (!emit1(JSOp::Hole)) {
return false;
}
} else {
if (!emitTree(elem, ValueUsage::WantValue)) {
// [stack] ARRAY INDEX? VALUE
return false;
}
}
if (afterSpread) {
if (!emit1(JSOp::InitElemInc)) {
// [stack] ARRAY (INDEX+1)
return false;
}
} else {
if (!emitUint32Operand(JSOp::InitElemArray, index)) {
// [stack] ARRAY
return false;
}
}
}
index++;
}
MOZ_ASSERT(index == count);
if (afterSpread) {
if (!emit1(JSOp::Pop)) {
// [stack] ARRAY
return false;
}
}
return true;
}
bool BytecodeEmitter::emitSpreadIntoArray(UnaryNode* elem) {
MOZ_ASSERT(elem->isKind(ParseNodeKind::Spread));
if (!updateSourceCoordNotes(elem->pn_pos.begin)) {
// [stack] VALUE
return false;
}
SelfHostedIter selfHostedIter = getSelfHostedIterFor(elem->kid());
MOZ_ASSERT(selfHostedIter == SelfHostedIter::Deny ||
selfHostedIter == SelfHostedIter::AllowContent);
if (!emitIterator(selfHostedIter)) {
// [stack] NEXT ITER
return false;
}
if (!emitUint32Operand(JSOp::NewArray, 0)) {
// [stack] NEXT ITER ARRAY
return false;
}
if (!emitNumberOp(0)) {
// [stack] NEXT ITER ARRAY INDEX
return false;
}
if (!emitSpread(selfHostedIter)) {
// [stack] ARRAY INDEX
return false;
}
if (!emit1(JSOp::Pop)) {
// [stack] ARRAY
return false;
}
return true;
}
#ifdef ENABLE_RECORD_TUPLE
bool BytecodeEmitter::emitRecordLiteral(ListNode* record) {
if (!emitUint32Operand(JSOp::InitRecord, record->count())) {
// [stack] RECORD
return false;
}
for (ParseNode* propdef : record->contents()) {
if (propdef->isKind(ParseNodeKind::Spread)) {
if (!emitTree(propdef->as<UnaryNode>().kid())) {
// [stack] RECORD SPREADEE
return false;
}
if (!emit1(JSOp::AddRecordSpread)) {
// [stack] RECORD
return false;
}
} else {
BinaryNode* prop = &propdef->as<BinaryNode>();
ParseNode* key = prop->left();
ParseNode* value = prop->right();
switch (key->getKind()) {
case ParseNodeKind::ObjectPropertyName:
if (!emitStringOp(JSOp::String, key->as<NameNode>().atom())) {
return false;
}
break;
case ParseNodeKind::ComputedName:
if (!emitTree(key->as<UnaryNode>().kid())) {
return false;
}
break;
default:
MOZ_ASSERT(key->isKind(ParseNodeKind::StringExpr) ||
key->isKind(ParseNodeKind::NumberExpr) ||
key->isKind(ParseNodeKind::BigIntExpr));
if (!emitTree(key)) {
return false;
}
break;
}
// [stack] RECORD KEY
if (!emitTree(value)) {
// [stack] RECORD KEY VALUE
return false;
}
if (!emit1(JSOp::AddRecordProperty)) {
// [stack] RECORD
return false;
}
}
}
if (!emit1(JSOp::FinishRecord)) {
// [stack] RECORD
return false;
}
return true;
}
bool BytecodeEmitter::emitTupleLiteral(ListNode* tuple) {
if (!emitUint32Operand(JSOp::InitTuple, tuple->count())) {
// [stack] TUPLE
return false;
}
for (ParseNode* elt : tuple->contents()) {
if (elt->isKind(ParseNodeKind::Spread)) {
ParseNode* expr = elt->as<UnaryNode>().kid();
auto selfHostedIter = getSelfHostedIterFor(expr);
if (!emitIterable(expr, selfHostedIter)) {
// [stack] TUPLE ITERABLE
return false;
}
if (!emitIterator(selfHostedIter)) {
// [stack] TUPLE NEXT ITER
return false;
}
if (!emit2(JSOp::Pick, 2)) {
// [stack] NEXT ITER TUPLE
return false;
}
if (!emitSpread(selfHostedIter, /* spreadeeStackItems = */ 1,
JSOp::AddTupleElement)) {
// [stack] TUPLE
return false;
}
} else {
// Update location to throw errors about non-primitive elements
// in the correct position.
if (!updateSourceCoordNotesIfNonLiteral(elt)) {
return false;
}
if (!emitTree(elt)) {
// [stack] TUPLE VALUE
return false;
}
if (!emit1(JSOp::AddTupleElement)) {
// [stack] TUPLE
return false;
}
}
}
if (!emit1(JSOp::FinishTuple)) {
// [stack] TUPLE
return false;
}
return true;
}
#endif
static inline JSOp UnaryOpParseNodeKindToJSOp(ParseNodeKind pnk) {
switch (pnk) {
case ParseNodeKind::ThrowStmt:
return JSOp::Throw;
case ParseNodeKind::VoidExpr:
return JSOp::Void;
case ParseNodeKind::NotExpr:
return JSOp::Not;
case ParseNodeKind::BitNotExpr:
return JSOp::BitNot;
case ParseNodeKind::PosExpr:
return JSOp::Pos;
case ParseNodeKind::NegExpr:
return JSOp::Neg;
default:
MOZ_CRASH("unexpected unary op");
}
}
bool BytecodeEmitter::emitUnary(UnaryNode* unaryNode) {
if (!updateSourceCoordNotes(unaryNode->pn_pos.begin)) {
return false;
}
JSOp op = UnaryOpParseNodeKindToJSOp(unaryNode->getKind());
ValueUsage valueUsage =
op == JSOp::Void ? ValueUsage::IgnoreValue : ValueUsage::WantValue;
if (!emitTree(unaryNode->kid(), valueUsage)) {
return false;
}
return emit1(op);
}
bool BytecodeEmitter::emitTypeof(UnaryNode* typeofNode, JSOp op) {
MOZ_ASSERT(op == JSOp::Typeof || op == JSOp::TypeofExpr);
if (!updateSourceCoordNotes(typeofNode->pn_pos.begin)) {
return false;
}
if (!emitTree(typeofNode->kid())) {
return false;
}
return emit1(op);
}
bool BytecodeEmitter::emitFunctionFormalParameters(ParamsBodyNode* paramsBody) {
FunctionBox* funbox = sc->asFunctionBox();
bool hasRest = funbox->hasRest();
FunctionParamsEmitter fpe(this, funbox);
for (ParseNode* arg : paramsBody->parameters()) {
ParseNode* bindingElement = arg;
ParseNode* initializer = nullptr;
if (arg->isKind(ParseNodeKind::AssignExpr)) {
bindingElement = arg->as<BinaryNode>().left();
initializer = arg->as<BinaryNode>().right();
}
bool hasInitializer = !!initializer;
bool isRest =
hasRest && arg->pn_next == *std::end(paramsBody->parameters());
bool isDestructuring = !bindingElement->isKind(ParseNodeKind::Name);
// Left-hand sides are either simple names or destructuring patterns.
MOZ_ASSERT(bindingElement->isKind(ParseNodeKind::Name) ||
bindingElement->isKind(ParseNodeKind::ArrayExpr) ||
bindingElement->isKind(ParseNodeKind::ObjectExpr));
auto emitDefaultInitializer = [this, &initializer, &bindingElement]() {
// [stack]
if (!this->emitInitializer(initializer, bindingElement)) {
// [stack] DEFAULT
return false;
}
return true;
};
auto emitDestructuring = [this, &bindingElement]() {
// [stack] ARG
if (!this->emitDestructuringOps(&bindingElement->as<ListNode>(),
DestructuringFlavor::Declaration)) {
// [stack] ARG
return false;
}
return true;
};
if (isRest) {
if (isDestructuring) {
if (!fpe.prepareForDestructuringRest()) {
// [stack]
return false;
}
if (!emitDestructuring()) {
// [stack]
return false;
}
if (!fpe.emitDestructuringRestEnd()) {
// [stack]
return false;
}
} else {
auto paramName = bindingElement->as<NameNode>().name();
if (!fpe.emitRest(paramName)) {
// [stack]
return false;
}
}
continue;
}
if (isDestructuring) {
if (hasInitializer) {
if (!fpe.prepareForDestructuringDefaultInitializer()) {
// [stack]
return false;
}
if (!emitDefaultInitializer()) {
// [stack]
return false;
}
if (!fpe.prepareForDestructuringDefault()) {
// [stack]
return false;
}
if (!emitDestructuring()) {
// [stack]
return false;
}
if (!fpe.emitDestructuringDefaultEnd()) {
// [stack]
return false;
}
} else {
if (!fpe.prepareForDestructuring()) {
// [stack]
return false;
}
if (!emitDestructuring()) {
// [stack]
return false;
}
if (!fpe.emitDestructuringEnd()) {
// [stack]
return false;
}
}
continue;
}
if (hasInitializer) {
if (!fpe.prepareForDefault()) {
// [stack]
return false;
}
if (!emitDefaultInitializer()) {
// [stack]
return false;
}
auto paramName = bindingElement->as<NameNode>().name();
if (!fpe.emitDefaultEnd(paramName)) {
// [stack]
return false;
}
continue;
}
auto paramName = bindingElement->as<NameNode>().name();
if (!fpe.emitSimple(paramName)) {
// [stack]
return false;
}
}
return true;
}
bool BytecodeEmitter::emitInitializeFunctionSpecialNames() {
FunctionBox* funbox = sc->asFunctionBox();
// [stack]
auto emitInitializeFunctionSpecialName =
[](BytecodeEmitter* bce, TaggedParserAtomIndex name, JSOp op) {
// A special name must be slotful, either on the frame or on the
// call environment.
MOZ_ASSERT(bce->lookupName(name).hasKnownSlot());
NameOpEmitter noe(bce, name, NameOpEmitter::Kind::Initialize);
if (!noe.prepareForRhs()) {
// [stack]
return false;
}
if (!bce->emit1(op)) {
// [stack] THIS/ARGUMENTS/NEW.TARGET
return false;
}
if (!noe.emitAssignment()) {
// [stack] THIS/ARGUMENTS/NEW.TARGET
return false;
}
if (!bce->emit1(JSOp::Pop)) {
// [stack]
return false;
}
return true;
};
// Do nothing if the function doesn't have an arguments binding.
if (funbox->needsArgsObj()) {
// Self-hosted code should use the more efficient ArgumentsLength and
// GetArgument intrinsics instead of `arguments`.
MOZ_ASSERT(emitterMode != BytecodeEmitter::SelfHosting);
if (!emitInitializeFunctionSpecialName(
this, TaggedParserAtomIndex::WellKnown::arguments(),
JSOp::Arguments)) {
// [stack]
return false;
}
}
// Do nothing if the function doesn't have a this-binding (this
// happens for instance if it doesn't use this/eval or if it's an
// arrow function).
if (funbox->functionHasThisBinding()) {
if (!emitInitializeFunctionSpecialName(
this, TaggedParserAtomIndex::WellKnown::dot_this_(),
JSOp::FunctionThis)) {
return false;
}
}
// Do nothing if the function doesn't have a new.target-binding (this happens
// for instance if it doesn't use new.target/eval or if it's an arrow
// function).
if (funbox->functionHasNewTargetBinding()) {
if (!emitInitializeFunctionSpecialName(
this, TaggedParserAtomIndex::WellKnown::dot_newTarget_(),
JSOp::NewTarget)) {
return false;
}
}
// Do nothing if the function doesn't implicitly return a promise result.
if (funbox->needsPromiseResult()) {
if (!emitInitializeFunctionSpecialName(
this, TaggedParserAtomIndex::WellKnown::dot_generator_(),
JSOp::Generator)) {
// [stack]
return false;
}
}
return true;
}
bool BytecodeEmitter::emitLexicalInitialization(NameNode* name) {
return emitLexicalInitialization(name->name());
}
bool BytecodeEmitter::emitLexicalInitialization(TaggedParserAtomIndex name) {
NameOpEmitter noe(this, name, NameOpEmitter::Kind::Initialize);
if (!noe.prepareForRhs()) {
return false;
}
// The caller has pushed the RHS to the top of the stack. Assert that the
// binding can be initialized without a binding object on the stack, and that
// no JSOp::BindName or JSOp::BindGName ops were emitted.
MOZ_ASSERT(noe.loc().isLexical() || noe.loc().isSynthetic() ||
noe.loc().isPrivateMethod());
MOZ_ASSERT(!noe.emittedBindOp());
if (!noe.emitAssignment()) {
return false;
}
return true;
}
static MOZ_ALWAYS_INLINE ParseNode* FindConstructor(ListNode* classMethods) {
for (ParseNode* classElement : classMethods->contents()) {
ParseNode* unwrappedElement = classElement;
if (unwrappedElement->is<LexicalScopeNode>()) {
unwrappedElement = unwrappedElement->as<LexicalScopeNode>().scopeBody();
}
if (unwrappedElement->is<ClassMethod>()) {
ClassMethod& method = unwrappedElement->as<ClassMethod>();
ParseNode& methodName = method.name();
if (!method.isStatic() &&
(methodName.isKind(ParseNodeKind::ObjectPropertyName) ||
methodName.isKind(ParseNodeKind::StringExpr)) &&
methodName.as<NameNode>().atom() ==
TaggedParserAtomIndex::WellKnown::constructor()) {
return classElement;
}
}
}
return nullptr;
}
bool BytecodeEmitter::emitNewPrivateName(TaggedParserAtomIndex bindingName,
TaggedParserAtomIndex symbolName) {
if (!emitAtomOp(JSOp::NewPrivateName, symbolName)) {
// [stack] HERITAGE PRIVATENAME
return false;
}
// Add a binding for #name => privatename
if (!emitLexicalInitialization(bindingName)) {
// [stack] HERITAGE PRIVATENAME
return false;
}
// Pop Private name off the stack.
if (!emit1(JSOp::Pop)) {
// [stack] HERITAGE
return false;
}
return true;
}
bool BytecodeEmitter::emitNewPrivateNames(
TaggedParserAtomIndex privateBrandName, ListNode* classMembers) {
bool hasPrivateBrand = false;
for (ParseNode* classElement : classMembers->contents()) {
ParseNode* elementName;
if (classElement->is<ClassMethod>()) {
elementName = &classElement->as<ClassMethod>().name();
} else if (classElement->is<ClassField>()) {
elementName = &classElement->as<ClassField>().name();
} else {
continue;
}
if (!elementName->isKind(ParseNodeKind::PrivateName)) {
continue;
}
// Non-static private methods' private names are optimized away.
bool isOptimized = false;
if (classElement->is<ClassMethod>() &&
!classElement->as<ClassMethod>().isStatic()) {
hasPrivateBrand = true;
if (classElement->as<ClassMethod>().accessorType() ==
AccessorType::None) {
isOptimized = true;
}
}
if (!isOptimized) {
auto privateName = elementName->as<NameNode>().name();
if (!emitNewPrivateName(privateName, privateName)) {
return false;
}
}
}
if (hasPrivateBrand) {
// We don't make a private name for every optimized method, but we need one
// private name per class, the `.privateBrand`.
if (!emitNewPrivateName(
TaggedParserAtomIndex::WellKnown::dot_privateBrand_(),
privateBrandName)) {
return false;
}
}
return true;
}
// This follows ES6 14.5.14 (ClassDefinitionEvaluation) and ES6 14.5.15
// (BindingClassDeclarationEvaluation).
bool BytecodeEmitter::emitClass(
ClassNode* classNode,
ClassNameKind nameKind /* = ClassNameKind::BindingName */,
TaggedParserAtomIndex
nameForAnonymousClass /* = TaggedParserAtomIndex::null() */) {
MOZ_ASSERT((nameKind == ClassNameKind::InferredName) ==
bool(nameForAnonymousClass));
ParseNode* heritageExpression = classNode->heritage();
ListNode* classMembers = classNode->memberList();
ParseNode* constructor = FindConstructor(classMembers);
// If |nameKind != ClassNameKind::ComputedName|
// [stack]
// Else
// [stack] NAME
ClassEmitter ce(this);
TaggedParserAtomIndex innerName;
ClassEmitter::Kind kind = ClassEmitter::Kind::Expression;
if (ClassNames* names = classNode->names()) {
MOZ_ASSERT(nameKind == ClassNameKind::BindingName);
innerName = names->innerBinding()->name();
MOZ_ASSERT(innerName);
if (names->outerBinding()) {
MOZ_ASSERT(names->outerBinding()->name());
MOZ_ASSERT(names->outerBinding()->name() == innerName);
kind = ClassEmitter::Kind::Declaration;
}
}
if (LexicalScopeNode* scopeBindings = classNode->scopeBindings()) {
if (!ce.emitScope(scopeBindings->scopeBindings())) {
// [stack]
return false;
}
}
bool isDerived = !!heritageExpression;
if (isDerived) {
if (!updateSourceCoordNotes(classNode->pn_pos.begin)) {
return false;
}
if (!markStepBreakpoint()) {
return false;
}
if (!emitTree(heritageExpression)) {
// [stack] HERITAGE
return false;
}
}
// The class body scope holds any private names. Those mustn't be visible in
// the heritage expression and hence the scope must be emitted after the
// heritage expression.
if (ClassBodyScopeNode* bodyScopeBindings = classNode->bodyScopeBindings()) {
if (!ce.emitBodyScope(bodyScopeBindings->scopeBindings())) {
// [stack] HERITAGE
return false;
}
// The spec does not say anything about private brands being symbols. It's
// an implementation detail. So we can give the special private brand
// symbol any description we want and users won't normally see it. For
// debugging, use the class name.
auto privateBrandName = innerName;
if (!innerName) {
privateBrandName = nameForAnonymousClass
? nameForAnonymousClass
: TaggedParserAtomIndex::WellKnown::anonymous();
}
if (!emitNewPrivateNames(privateBrandName, classMembers)) {
return false;
}
}
bool hasNameOnStack = nameKind == ClassNameKind::ComputedName;
if (isDerived) {
if (!ce.emitDerivedClass(innerName, nameForAnonymousClass,
hasNameOnStack)) {
// [stack] HOMEOBJ HERITAGE
return false;
}
} else {
if (!ce.emitClass(innerName, nameForAnonymousClass, hasNameOnStack)) {
// [stack] HOMEOBJ
return false;
}
}
// Stack currently has HOMEOBJ followed by optional HERITAGE. When HERITAGE
// is not used, an implicit value of %FunctionPrototype% is implied.
// See |Parser::classMember(...)| for the reason why |.initializers| is
// created within its own scope.
Maybe<LexicalScopeEmitter> lse;
FunctionNode* ctor;
#ifdef ENABLE_DECORATORS
bool extraInitializersPresent = false;
#endif
if (constructor->is<LexicalScopeNode>()) {
LexicalScopeNode* constructorScope = &constructor->as<LexicalScopeNode>();
MOZ_ASSERT(!constructorScope->isEmptyScope());
#ifdef ENABLE_DECORATORS
// With decorators enabled we expect to see |.initializers|,
// and |.instanceExtraInitializers| in this scope.
MOZ_ASSERT(constructorScope->scopeBindings()->length == 2);
MOZ_ASSERT(GetScopeDataTrailingNames(constructorScope->scopeBindings())[0]
.name() ==
TaggedParserAtomIndex::WellKnown::dot_initializers_());
MOZ_ASSERT(
GetScopeDataTrailingNames(constructorScope->scopeBindings())[1]
.name() ==
TaggedParserAtomIndex::WellKnown::dot_instanceExtraInitializers_());
// We should only call this code if we know decorators are present, see bug
// 1871147.
lse.emplace(this);
if (!lse->emitScope(ScopeKind::Lexical,
constructorScope->scopeBindings())) {
return false;
}
if (!ce.prepareForExtraInitializers(TaggedParserAtomIndex::WellKnown::
dot_instanceExtraInitializers_())) {
return false;
}
if (classNode->addInitializerFunction()) {
DecoratorEmitter de(this);
if (!de.emitCreateAddInitializerFunction(
classNode->addInitializerFunction(),
TaggedParserAtomIndex::WellKnown::
dot_instanceExtraInitializers_())) {
// [stack] HOMEOBJ HERITAGE? ADDINIT
return false;
}
if (!emitUnpickN(isDerived ? 2 : 1)) {
// [stack] ADDINIT HOMEOBJ HERITAGE?
return false;
}
extraInitializersPresent = true;
}
#else
// The constructor scope should only contain the |.initializers| binding.
MOZ_ASSERT(constructorScope->scopeBindings()->length == 1);
MOZ_ASSERT(GetScopeDataTrailingNames(constructorScope->scopeBindings())[0]
.name() ==
TaggedParserAtomIndex::WellKnown::dot_initializers_());
#endif
auto needsInitializer = [](ParseNode* propdef) {
return NeedsFieldInitializer(propdef, false) ||
NeedsAccessorInitializer(propdef, false);
};
// As an optimization omit the |.initializers| binding when no instance
// fields or private methods are present.
bool needsInitializers =
std::any_of(classMembers->contents().begin(),
classMembers->contents().end(), needsInitializer);
if (needsInitializers) {
#ifndef ENABLE_DECORATORS
lse.emplace(this);
if (!lse->emitScope(ScopeKind::Lexical,
constructorScope->scopeBindings())) {
return false;
}
#endif
// Any class with field initializers will have a constructor
if (!emitCreateMemberInitializers(ce, classMembers,
FieldPlacement::Instance
#ifdef ENABLE_DECORATORS
,
isDerived
#endif
)) {
return false;
}
}
ctor = &constructorScope->scopeBody()->as<ClassMethod>().method();
} else {
// The |.initializers| binding is never emitted when in self-hosting mode.
MOZ_ASSERT(emitterMode == BytecodeEmitter::SelfHosting);
ctor = &constructor->as<ClassMethod>().method();
}
bool needsHomeObject = ctor->funbox()->needsHomeObject();
// HERITAGE is consumed inside emitFunction.
if (nameKind == ClassNameKind::InferredName) {
if (!setFunName(ctor->funbox(), nameForAnonymousClass)) {
return false;
}
}
if (!emitFunction(ctor, isDerived)) {
// [stack] HOMEOBJ CTOR
return false;
}
if (lse.isSome()) {
if (!lse->emitEnd()) {
return false;
}
lse.reset();
}
if (!ce.emitInitConstructor(needsHomeObject)) {
// [stack] CTOR HOMEOBJ
return false;
}
if (!emitCreateFieldKeys(classMembers, FieldPlacement::Instance)) {
return false;
}
#ifdef ENABLE_DECORATORS
if (!emit1(JSOp::Undefined)) {
// [stack] ADDINIT? CTOR HOMEOBJ UNDEFINED
return false;
}
if (!emitUnpickN(2)) {
// [stack] ADDINIT? UNDEFINED CTOR HOMEOBJ
}
#endif
if (!emitCreateMemberInitializers(ce, classMembers, FieldPlacement::Static
#ifdef ENABLE_DECORATORS
,
false
#endif
)) {
return false;
}
#ifdef ENABLE_DECORATORS
if (!emitPickN(2)) {
// [stack] ADDINIT? CTOR HOMEOBJ UNDEFINED
return false;
}
if (!emitPopN(1)) {
// [stack] ADDINIT? CTOR HOMEOBJ
return false;
}
#endif
if (!emitCreateFieldKeys(classMembers, FieldPlacement::Static)) {
return false;
}
if (!emitPropertyList(classMembers, ce, ClassBody)) {
// [stack] CTOR HOMEOBJ
return false;
}
#ifdef ENABLE_DECORATORS
if (extraInitializersPresent) {
if (!emitPickN(2)) {
// [stack] CTOR HOMEOBJ ADDINIT
return false;
}
if (!emitPopN(1)) {
// [stack] CTOR HOMEOBJ
return false;
}
}
#endif
if (!ce.emitBinding()) {
// [stack] CTOR
return false;
}
if (!emitInitializeStaticFields(classMembers)) {
// [stack] CTOR
return false;
}
#if ENABLE_DECORATORS
if (!ce.prepareForDecorators()) {
// [stack] CTOR
return false;
}
if (classNode->decorators() != nullptr) {
DecoratorEmitter de(this);
NameNode* className =
classNode->names() ? classNode->names()->innerBinding() : nullptr;
if (!de.emitApplyDecoratorsToClassDefinition(className,
classNode->decorators())) {
// [stack] CTOR
return false;
}
}
#endif
if (!ce.emitEnd(kind)) {
// [stack] # class declaration
// [stack]
// [stack] # class expression
// [stack] CTOR
return false;
}
return true;
}
bool BytecodeEmitter::emitExportDefault(BinaryNode* exportNode) {
MOZ_ASSERT(exportNode->isKind(ParseNodeKind::ExportDefaultStmt));
ParseNode* valueNode = exportNode->left();
if (valueNode->isDirectRHSAnonFunction()) {
MOZ_ASSERT(exportNode->right());
if (!emitAnonymousFunctionWithName(
valueNode, TaggedParserAtomIndex::WellKnown::default_())) {
return false;
}
} else {
if (!emitTree(valueNode)) {
return false;
}
}
if (ParseNode* binding = exportNode->right()) {
if (!emitLexicalInitialization(&binding->as<NameNode>())) {
return false;
}
if (!emit1(JSOp::Pop)) {
return false;
}
}
return true;
}
bool BytecodeEmitter::emitTree(
ParseNode* pn, ValueUsage valueUsage /* = ValueUsage::WantValue */,
EmitLineNumberNote emitLineNote /* = EMIT_LINENOTE */) {
AutoCheckRecursionLimit recursion(fc);
if (!recursion.check(fc)) {
return false;
}
/* Emit notes to tell the current bytecode's source line number.
However, a couple trees require special treatment; see the
relevant emitter functions for details. */
if (emitLineNote == EMIT_LINENOTE &&
!ParseNodeRequiresSpecialLineNumberNotes(pn)) {
if (!updateLineNumberNotes(pn->pn_pos.begin)) {
return false;
}
}
switch (pn->getKind()) {
case ParseNodeKind::Function:
if (!emitFunction(&pn->as<FunctionNode>())) {
return false;
}
break;
case ParseNodeKind::ParamsBody:
MOZ_ASSERT_UNREACHABLE(
"ParamsBody should be handled in emitFunctionScript.");
break;
case ParseNodeKind::IfStmt:
if (!emitIf(&pn->as<TernaryNode>())) {
return false;
}
break;
case ParseNodeKind::SwitchStmt:
if (!emitSwitch(&pn->as<SwitchStatement>())) {
return false;
}
break;
case ParseNodeKind::WhileStmt:
if (!emitWhile(&pn->as<BinaryNode>())) {
return false;
}
break;
case ParseNodeKind::DoWhileStmt:
if (!emitDo(&pn->as<BinaryNode>())) {
return false;
}
break;
case ParseNodeKind::ForStmt:
if (!emitFor(&pn->as<ForNode>())) {
return false;
}
break;
case ParseNodeKind::BreakStmt:
// Ensure that the column of the 'break' is set properly.
if (!updateSourceCoordNotes(pn->pn_pos.begin)) {
return false;
}
if (!markStepBreakpoint()) {
return false;
}
if (!emitBreak(pn->as<BreakStatement>().label())) {
return false;
}
break;
case ParseNodeKind::ContinueStmt:
// Ensure that the column of the 'continue' is set properly.
if (!updateSourceCoordNotes(pn->pn_pos.begin)) {
return false;
}
if (!markStepBreakpoint()) {
return false;
}
if (!emitContinue(pn->as<ContinueStatement>().label())) {
return false;
}
break;
case ParseNodeKind::WithStmt:
if (!emitWith(&pn->as<BinaryNode>())) {
return false;
}
break;
case ParseNodeKind::TryStmt:
if (!emitTry(&pn->as<TryNode>())) {
return false;
}
break;
case ParseNodeKind::Catch:
if (!emitCatch(&pn->as<BinaryNode>())) {
return false;
}
break;
case ParseNodeKind::VarStmt:
if (!emitDeclarationList(&pn->as<ListNode>())) {
return false;
}
break;
case ParseNodeKind::ReturnStmt:
if (!emitReturn(&pn->as<UnaryNode>())) {
return false;
}
break;
case ParseNodeKind::YieldStarExpr:
if (!emitYieldStar(pn->as<UnaryNode>().kid())) {
return false;
}
break;
case ParseNodeKind::Generator:
if (!emit1(JSOp::Generator)) {
return false;
}
break;
case ParseNodeKind::InitialYield:
if (!emitInitialYield(&pn->as<UnaryNode>())) {
return false;
}
break;
case ParseNodeKind::YieldExpr:
if (!emitYield(&pn->as<UnaryNode>())) {
return false;
}
break;
case ParseNodeKind::AwaitExpr:
if (!emitAwaitInInnermostScope(&pn->as<UnaryNode>())) {
return false;
}
break;
case ParseNodeKind::StatementList:
if (!emitStatementList(&pn->as<ListNode>())) {
return false;
}
break;
case ParseNodeKind::EmptyStmt:
break;
case ParseNodeKind::ExpressionStmt:
if (!emitExpressionStatement(&pn->as<UnaryNode>())) {
return false;
}
break;
case ParseNodeKind::LabelStmt:
if (!emitLabeledStatement(&pn->as<LabeledStatement>())) {
return false;
}
break;
case ParseNodeKind::CommaExpr:
if (!emitSequenceExpr(&pn->as<ListNode>(), valueUsage)) {
return false;
}
break;
case ParseNodeKind::InitExpr:
case ParseNodeKind::AssignExpr:
case ParseNodeKind::AddAssignExpr:
case ParseNodeKind::SubAssignExpr:
case ParseNodeKind::BitOrAssignExpr:
case ParseNodeKind::BitXorAssignExpr:
case ParseNodeKind::BitAndAssignExpr:
case ParseNodeKind::LshAssignExpr:
case ParseNodeKind::RshAssignExpr:
case ParseNodeKind::UrshAssignExpr:
case ParseNodeKind::MulAssignExpr:
case ParseNodeKind::DivAssignExpr:
case ParseNodeKind::ModAssignExpr:
case ParseNodeKind::PowAssignExpr: {
BinaryNode* assignNode = &pn->as<BinaryNode>();
if (!emitAssignmentOrInit(assignNode->getKind(), assignNode->left(),
assignNode->right())) {
return false;
}
break;
}
case ParseNodeKind::CoalesceAssignExpr:
case ParseNodeKind::OrAssignExpr:
case ParseNodeKind::AndAssignExpr:
if (!emitShortCircuitAssignment(&pn->as<AssignmentNode>())) {
return false;
}
break;
case ParseNodeKind::ConditionalExpr:
if (!emitConditionalExpression(pn->as<ConditionalExpression>(),
valueUsage)) {
return false;
}
break;
case ParseNodeKind::OrExpr:
case ParseNodeKind::CoalesceExpr:
case ParseNodeKind::AndExpr:
if (!emitShortCircuit(&pn->as<ListNode>(), valueUsage)) {
return false;
}
break;
case ParseNodeKind::AddExpr:
case ParseNodeKind::SubExpr:
case ParseNodeKind::BitOrExpr:
case ParseNodeKind::BitXorExpr:
case ParseNodeKind::BitAndExpr:
case ParseNodeKind::StrictEqExpr:
case ParseNodeKind::EqExpr:
case ParseNodeKind::StrictNeExpr:
case ParseNodeKind::NeExpr:
case ParseNodeKind::LtExpr:
case ParseNodeKind::LeExpr:
case ParseNodeKind::GtExpr:
case ParseNodeKind::GeExpr:
case ParseNodeKind::InExpr:
case ParseNodeKind::InstanceOfExpr:
case ParseNodeKind::LshExpr:
case ParseNodeKind::RshExpr:
case ParseNodeKind::UrshExpr:
case ParseNodeKind::MulExpr:
case ParseNodeKind::DivExpr:
case ParseNodeKind::ModExpr:
if (!emitLeftAssociative(&pn->as<ListNode>())) {
return false;
}
break;
case ParseNodeKind::PrivateInExpr:
if (!emitPrivateInExpr(&pn->as<ListNode>())) {
return false;
}
break;
case ParseNodeKind::PowExpr:
if (!emitRightAssociative(&pn->as<ListNode>())) {
return false;
}
break;
case ParseNodeKind::TypeOfNameExpr:
if (!emitTypeof(&pn->as<UnaryNode>(), JSOp::Typeof)) {
return false;
}
break;
case ParseNodeKind::TypeOfExpr:
if (!emitTypeof(&pn->as<UnaryNode>(), JSOp::TypeofExpr)) {
return false;
}
break;
case ParseNodeKind::ThrowStmt:
if (!updateSourceCoordNotes(pn->pn_pos.begin)) {
return false;
}
if (!markStepBreakpoint()) {
return false;
}
[[fallthrough]];
case ParseNodeKind::VoidExpr:
case ParseNodeKind::NotExpr:
case ParseNodeKind::BitNotExpr:
case ParseNodeKind::PosExpr:
case ParseNodeKind::NegExpr:
if (!emitUnary(&pn->as<UnaryNode>())) {
return false;
}
break;
case ParseNodeKind::PreIncrementExpr:
case ParseNodeKind::PreDecrementExpr:
case ParseNodeKind::PostIncrementExpr:
case ParseNodeKind::PostDecrementExpr:
if (!emitIncOrDec(&pn->as<UnaryNode>(), valueUsage)) {
return false;
}
break;
case ParseNodeKind::DeleteNameExpr:
if (!emitDeleteName(&pn->as<UnaryNode>())) {
return false;
}
break;
case ParseNodeKind::DeletePropExpr:
if (!emitDeleteProperty(&pn->as<UnaryNode>())) {
return false;
}
break;
case ParseNodeKind::DeleteElemExpr:
if (!emitDeleteElement(&pn->as<UnaryNode>())) {
return false;
}
break;
case ParseNodeKind::DeleteExpr:
if (!emitDeleteExpression(&pn->as<UnaryNode>())) {
return false;
}
break;
case ParseNodeKind::DeleteOptionalChainExpr:
if (!emitDeleteOptionalChain(&pn->as<UnaryNode>())) {
return false;
}
break;
case ParseNodeKind::OptionalChain:
if (!emitOptionalChain(&pn->as<UnaryNode>(), valueUsage)) {
return false;
}
break;
case ParseNodeKind::DotExpr: {
PropertyAccess* prop = &pn->as<PropertyAccess>();
bool isSuper = prop->isSuper();
PropOpEmitter poe(this, PropOpEmitter::Kind::Get,
isSuper ? PropOpEmitter::ObjKind::Super
: PropOpEmitter::ObjKind::Other);
if (!poe.prepareForObj()) {
return false;
}
if (isSuper) {
UnaryNode* base = &prop->expression().as<UnaryNode>();
if (!emitGetThisForSuperBase(base)) {
// [stack] THIS
return false;
}
} else {
if (!emitPropLHS(prop)) {
// [stack] OBJ
return false;
}
}
if (!poe.emitGet(prop->key().atom())) {
// [stack] PROP
return false;
}
break;
}
case ParseNodeKind::ArgumentsLength: {
if (sc->isFunctionBox() &&
sc->asFunctionBox()->isEligibleForArgumentsLength() &&
!sc->asFunctionBox()->needsArgsObj()) {
if (!emit1(JSOp::ArgumentsLength)) {
return false;
}
} else {
PropOpEmitter poe(this, PropOpEmitter::Kind::Get,
PropOpEmitter::ObjKind::Other);
if (!poe.prepareForObj()) {
return false;
}
NameOpEmitter noe(this, TaggedParserAtomIndex::WellKnown::arguments(),
NameOpEmitter::Kind::Get);
if (!noe.emitGet()) {
return false;
}
if (!poe.emitGet(TaggedParserAtomIndex::WellKnown::length())) {
return false;
}
}
break;
}
case ParseNodeKind::ElemExpr: {
PropertyByValue* elem = &pn->as<PropertyByValue>();
bool isSuper = elem->isSuper();
MOZ_ASSERT(!elem->key().isKind(ParseNodeKind::PrivateName));
ElemOpEmitter eoe(this, ElemOpEmitter::Kind::Get,
isSuper ? ElemOpEmitter::ObjKind::Super
: ElemOpEmitter::ObjKind::Other);
if (!emitElemObjAndKey(elem, isSuper, eoe)) {
// [stack] # if Super
// [stack] THIS KEY
// [stack] # otherwise
// [stack] OBJ KEY
return false;
}
if (!eoe.emitGet()) {
// [stack] ELEM
return false;
}
break;
}
case ParseNodeKind::PrivateMemberExpr: {
PrivateMemberAccess* privateExpr = &pn->as<PrivateMemberAccess>();
PrivateOpEmitter xoe(this, PrivateOpEmitter::Kind::Get,
privateExpr->privateName().name());
if (!emitTree(&privateExpr->expression())) {
// [stack] OBJ
return false;
}
if (!xoe.emitReference()) {
// [stack] OBJ NAME
return false;
}
if (!xoe.emitGet()) {
// [stack] VALUE
return false;
}
break;
}
case ParseNodeKind::NewExpr:
case ParseNodeKind::TaggedTemplateExpr:
case ParseNodeKind::CallExpr:
case ParseNodeKind::SuperCallExpr:
if (!emitCallOrNew(&pn->as<CallNode>(), valueUsage)) {
return false;
}
break;
case ParseNodeKind::LexicalScope:
if (!emitLexicalScope(&pn->as<LexicalScopeNode>())) {
return false;
}
break;
case ParseNodeKind::ConstDecl:
case ParseNodeKind::LetDecl:
if (!emitDeclarationList(&pn->as<ListNode>())) {
return false;
}
break;
case ParseNodeKind::ImportDecl:
MOZ_ASSERT(sc->isModuleContext());
break;
case ParseNodeKind::ExportStmt: {
MOZ_ASSERT(sc->isModuleContext());
UnaryNode* node = &pn->as<UnaryNode>();
ParseNode* decl = node->kid();
if (decl->getKind() != ParseNodeKind::ExportSpecList) {
if (!emitTree(decl)) {
return false;
}
}
break;
}
case ParseNodeKind::ExportDefaultStmt:
MOZ_ASSERT(sc->isModuleContext());
if (!emitExportDefault(&pn->as<BinaryNode>())) {
return false;
}
break;
case ParseNodeKind::ExportFromStmt:
MOZ_ASSERT(sc->isModuleContext());
break;
case ParseNodeKind::CallSiteObj:
if (!emitCallSiteObject(&pn->as<CallSiteNode>())) {
return false;
}
break;
case ParseNodeKind::ArrayExpr:
if (!emitArrayLiteral(&pn->as<ListNode>())) {
return false;
}
break;
case ParseNodeKind::ObjectExpr:
if (!emitObject(&pn->as<ListNode>())) {
return false;
}
break;
case ParseNodeKind::Name:
if (!emitGetName(&pn->as<NameNode>())) {
return false;
}
break;
case ParseNodeKind::PrivateName:
if (!emitGetPrivateName(&pn->as<NameNode>())) {
return false;
}
break;
case ParseNodeKind::TemplateStringListExpr:
if (!emitTemplateString(&pn->as<ListNode>())) {
return false;
}
break;
case ParseNodeKind::TemplateStringExpr:
case ParseNodeKind::StringExpr:
if (!emitStringOp(JSOp::String, pn->as<NameNode>().atom())) {
return false;
}
break;
case ParseNodeKind::NumberExpr:
if (!emitNumberOp(pn->as<NumericLiteral>().value())) {
return false;
}
break;
case ParseNodeKind::BigIntExpr:
if (!emitBigIntOp(&pn->as<BigIntLiteral>())) {
return false;
}
break;
case ParseNodeKind::RegExpExpr: {
GCThingIndex index;
if (!perScriptData().gcThingList().append(&pn->as<RegExpLiteral>(),
&index)) {
return false;
}
if (!emitRegExp(index)) {
return false;
}
break;
}
case ParseNodeKind::TrueExpr:
if (!emit1(JSOp::True)) {
return false;
}
break;
case ParseNodeKind::FalseExpr:
if (!emit1(JSOp::False)) {
return false;
}
break;
case ParseNodeKind::NullExpr:
if (!emit1(JSOp::Null)) {
return false;
}
break;
case ParseNodeKind::RawUndefinedExpr:
if (!emit1(JSOp::Undefined)) {
return false;
}
break;
case ParseNodeKind::ThisExpr:
if (!emitThisLiteral(&pn->as<ThisLiteral>())) {
return false;
}
break;
case ParseNodeKind::DebuggerStmt:
if (!updateSourceCoordNotes(pn->pn_pos.begin)) {
return false;
}
if (!markStepBreakpoint()) {
return false;
}
if (!emit1(JSOp::Debugger)) {
return false;
}
break;
case ParseNodeKind::ClassDecl:
if (!emitClass(&pn->as<ClassNode>())) {
return false;
}
break;
case ParseNodeKind::NewTargetExpr:
if (!emitNewTarget(&pn->as<NewTargetNode>())) {
return false;
}
break;
case ParseNodeKind::ImportMetaExpr:
if (!emit1(JSOp::ImportMeta)) {
return false;
}
break;
case ParseNodeKind::CallImportExpr: {
BinaryNode* spec = &pn->as<BinaryNode>().right()->as<BinaryNode>();
if (!emitTree(spec->left())) {
// [stack] specifier
return false;
}
if (!spec->right()->isKind(ParseNodeKind::PosHolder)) {
// [stack] specifier options
if (!emitTree(spec->right())) {
return false;
}
} else {
// [stack] specifier undefined
if (!emit1(JSOp::Undefined)) {
return false;
}
}
if (!emit1(JSOp::DynamicImport)) {
return false;
}
break;
}
case ParseNodeKind::SetThis:
if (!emitSetThis(&pn->as<BinaryNode>())) {
return false;
}
break;
#ifdef ENABLE_RECORD_TUPLE
case ParseNodeKind::RecordExpr:
if (!emitRecordLiteral(&pn->as<ListNode>())) {
return false;
}
break;
case ParseNodeKind::TupleExpr:
if (!emitTupleLiteral(&pn->as<ListNode>())) {
return false;
}
break;
#endif
case ParseNodeKind::PropertyNameExpr:
case ParseNodeKind::PosHolder:
MOZ_FALLTHROUGH_ASSERT(
"Should never try to emit ParseNodeKind::PosHolder or ::Property");
default:
MOZ_ASSERT(0);
}
return true;
}
static bool AllocSrcNote(FrontendContext* fc, SrcNotesVector& notes,
unsigned size, unsigned* index) {
size_t oldLength = notes.length();
if (MOZ_UNLIKELY(oldLength + size > MaxSrcNotesLength)) {
ReportAllocationOverflow(fc);
return false;
}
if (!notes.growByUninitialized(size)) {
return false;
}
*index = oldLength;
return true;
}
bool BytecodeEmitter::addTryNote(TryNoteKind kind, uint32_t stackDepth,
BytecodeOffset start, BytecodeOffset end) {
MOZ_ASSERT(!inPrologue());
return bytecodeSection().tryNoteList().append(kind, stackDepth, start, end);
}
bool BytecodeEmitter::newSrcNote(SrcNoteType type, unsigned* indexp) {
SrcNotesVector& notes = bytecodeSection().notes();
unsigned index;
/*
* Compute delta from the last annotated bytecode's offset. If it's too
* big to fit in sn, allocate one or more xdelta notes and reset sn.
*/
BytecodeOffset offset = bytecodeSection().offset();
ptrdiff_t delta = (offset - bytecodeSection().lastNoteOffset()).value();
bytecodeSection().setLastNoteOffset(offset);
auto allocator = [&](unsigned size) -> SrcNote* {
if (!AllocSrcNote(fc, notes, size, &index)) {
return nullptr;
}
return ¬es[index];
};
if (!SrcNoteWriter::writeNote(type, delta, allocator)) {
return false;
}
if (indexp) {
*indexp = index;
}
if (type == SrcNoteType::NewLine || type == SrcNoteType::SetLine) {
lastLineOnlySrcNoteIndex = index;
} else {
lastLineOnlySrcNoteIndex = LastSrcNoteIsNotLineOnly;
}
return true;
}
bool BytecodeEmitter::newSrcNote2(SrcNoteType type, ptrdiff_t offset,
unsigned* indexp) {
unsigned index;
if (!newSrcNote(type, &index)) {
return false;
}
if (!newSrcNoteOperand(offset)) {
return false;
}
if (indexp) {
*indexp = index;
}
return true;
}
bool BytecodeEmitter::convertLastNewLineToNewLineColumn(
JS::LimitedColumnNumberOneOrigin column) {
SrcNotesVector& notes = bytecodeSection().notes();
MOZ_ASSERT(lastLineOnlySrcNoteIndex == notes.length() - 1);
SrcNote* sn = ¬es[lastLineOnlySrcNoteIndex];
MOZ_ASSERT(sn->type() == SrcNoteType::NewLine);
SrcNoteWriter::convertNote(sn, SrcNoteType::NewLineColumn);
if (!newSrcNoteOperand(SrcNote::NewLineColumn::toOperand(column))) {
return false;
}
lastLineOnlySrcNoteIndex = LastSrcNoteIsNotLineOnly;
return true;
}
bool BytecodeEmitter::convertLastSetLineToSetLineColumn(
JS::LimitedColumnNumberOneOrigin column) {
SrcNotesVector& notes = bytecodeSection().notes();
// The Line operand is either 1 byte or 4 bytes.
MOZ_ASSERT(lastLineOnlySrcNoteIndex == notes.length() - 1 - 1 ||
lastLineOnlySrcNoteIndex == notes.length() - 1 - 4);
SrcNote* sn = ¬es[lastLineOnlySrcNoteIndex];
MOZ_ASSERT(sn->type() == SrcNoteType::SetLine);
SrcNoteWriter::convertNote(sn, SrcNoteType::SetLineColumn);
if (!newSrcNoteOperand(SrcNote::SetLineColumn::columnToOperand(column))) {
return false;
}
lastLineOnlySrcNoteIndex = LastSrcNoteIsNotLineOnly;
return true;
}
bool BytecodeEmitter::newSrcNoteOperand(ptrdiff_t operand) {
if (!SrcNote::isRepresentableOperand(operand)) {
reportError(nullptr, JSMSG_NEED_DIET, "script");
return false;
}
SrcNotesVector& notes = bytecodeSection().notes();
auto allocator = [&](unsigned size) -> SrcNote* {
unsigned index;
if (!AllocSrcNote(fc, notes, size, &index)) {
return nullptr;
}
return ¬es[index];
};
return SrcNoteWriter::writeOperand(operand, allocator);
}
bool BytecodeEmitter::intoScriptStencil(ScriptIndex scriptIndex) {
js::UniquePtr<ImmutableScriptData> immutableScriptData =
createImmutableScriptData();
if (!immutableScriptData) {
return false;
}
MOZ_ASSERT(outermostScope().hasNonSyntacticScopeOnChain() ==
sc->hasNonSyntacticScope());
auto& things = perScriptData().gcThingList().objects();
if (!compilationState.appendGCThings(fc, scriptIndex, things)) {
return false;
}
// Hand over the ImmutableScriptData instance generated by BCE.
auto* sharedData =
SharedImmutableScriptData::createWith(fc, std::move(immutableScriptData));
if (!sharedData) {
return false;
}
// De-duplicate the bytecode within the runtime.
if (!compilationState.sharedData.addAndShare(fc, scriptIndex, sharedData)) {
return false;
}
ScriptStencil& script = compilationState.scriptData[scriptIndex];
script.setHasSharedData();
// Update flags specific to functions.
if (sc->isFunctionBox()) {
FunctionBox* funbox = sc->asFunctionBox();
MOZ_ASSERT(&script == &funbox->functionStencil());
funbox->copyUpdatedImmutableFlags();
MOZ_ASSERT(script.isFunction());
} else {
ScriptStencilExtra& scriptExtra = compilationState.scriptExtra[scriptIndex];
sc->copyScriptExtraFields(scriptExtra);
}
return true;
}
SelfHostedIter BytecodeEmitter::getSelfHostedIterFor(ParseNode* parseNode) {
if (emitterMode == BytecodeEmitter::SelfHosting &&
parseNode->isKind(ParseNodeKind::CallExpr)) {
auto* callee = parseNode->as<CallNode>().callee();
if (callee->isName(TaggedParserAtomIndex::WellKnown::allowContentIter())) {
return SelfHostedIter::AllowContent;
}
if (callee->isName(
TaggedParserAtomIndex::WellKnown::allowContentIterWith())) {
return SelfHostedIter::AllowContentWith;
}
if (callee->isName(
TaggedParserAtomIndex::WellKnown::allowContentIterWithNext())) {
return SelfHostedIter::AllowContentWithNext;
}
}
return SelfHostedIter::Deny;
}
#if defined(DEBUG) || defined(JS_JITSPEW)
void BytecodeEmitter::dumpAtom(TaggedParserAtomIndex index) const {
parserAtoms().dump(index);
}
#endif