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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
#ifndef frontend_BytecodeSection_h
#define frontend_BytecodeSection_h
#include "mozilla/Attributes.h" // MOZ_STACK_CLASS
#include "mozilla/Maybe.h" // mozilla::Maybe
#include "mozilla/Span.h" // mozilla::Span
#include <stddef.h> // ptrdiff_t, size_t
#include <stdint.h> // uint16_t, int32_t, uint32_t
#include "frontend/AbstractScopePtr.h" // AbstractScopePtr, ScopeIndex
#include "frontend/BytecodeOffset.h" // BytecodeOffset
#include "frontend/CompilationStencil.h" // CompilationStencil, CompilationGCOutput, CompilationAtomCache
#include "frontend/FrontendContext.h" // FrontendContext
#include "frontend/JumpList.h" // JumpTarget
#include "frontend/NameCollections.h" // AtomIndexMap, PooledMapPtr
#include "frontend/ParseNode.h" // BigIntLiteral
#include "frontend/ParserAtom.h" // ParserAtomsTable, TaggedParserAtomIndex, ParserAtom
#include "frontend/SourceNotes.h" // SrcNote
#include "frontend/Stencil.h" // Stencils
#include "js/ColumnNumber.h" // JS::LimitedColumnNumberOneOrigin
#include "js/TypeDecls.h" // jsbytecode, JSContext
#include "js/Vector.h" // Vector
#include "vm/SharedStencil.h" // TryNote, ScopeNote, GCThingIndex
#include "vm/StencilEnums.h" // TryNoteKind
namespace js {
namespace frontend {
class FunctionBox;
struct MOZ_STACK_CLASS GCThingList {
// The BCE accumulates TaggedScriptThingIndex items so use a vector type. We
// reserve some stack slots to avoid allocating for most small scripts.
using ScriptThingsStackVector = Vector<TaggedScriptThingIndex, 8>;
CompilationState& compilationState;
ScriptThingsStackVector vector;
// Index of the first scope in the vector.
mozilla::Maybe<GCThingIndex> firstScopeIndex;
explicit GCThingList(FrontendContext* fc, CompilationState& compilationState)
: compilationState(compilationState), vector(fc) {}
[[nodiscard]] bool append(TaggedParserAtomIndex atom,
ParserAtom::Atomize atomize, GCThingIndex* index) {
*index = GCThingIndex(vector.length());
compilationState.parserAtoms.markUsedByStencil(atom, atomize);
if (!vector.emplaceBack(atom)) {
return false;
}
return true;
}
[[nodiscard]] bool append(ScopeIndex scope, GCThingIndex* index) {
*index = GCThingIndex(vector.length());
if (!vector.emplaceBack(scope)) {
return false;
}
if (!firstScopeIndex) {
firstScopeIndex.emplace(*index);
}
return true;
}
[[nodiscard]] bool append(BigIntLiteral* literal, GCThingIndex* index) {
*index = GCThingIndex(vector.length());
if (!vector.emplaceBack(literal->index())) {
return false;
}
return true;
}
[[nodiscard]] bool append(RegExpLiteral* literal, GCThingIndex* index) {
*index = GCThingIndex(vector.length());
if (!vector.emplaceBack(literal->index())) {
return false;
}
return true;
}
[[nodiscard]] bool append(ObjLiteralIndex objlit, GCThingIndex* index) {
*index = GCThingIndex(vector.length());
if (!vector.emplaceBack(objlit)) {
return false;
}
return true;
}
[[nodiscard]] bool append(FunctionBox* funbox, GCThingIndex* index);
[[nodiscard]] bool appendEmptyGlobalScope(GCThingIndex* index) {
*index = GCThingIndex(vector.length());
EmptyGlobalScopeType emptyGlobalScope;
if (!vector.emplaceBack(emptyGlobalScope)) {
return false;
}
if (!firstScopeIndex) {
firstScopeIndex.emplace(*index);
}
return true;
}
uint32_t length() const { return vector.length(); }
const ScriptThingsStackVector& objects() { return vector; }
AbstractScopePtr getScope(size_t index) const;
// Index of scope within CompilationStencil or Nothing is the scope is
// EmptyGlobalScopeType.
mozilla::Maybe<ScopeIndex> getScopeIndex(size_t index) const;
TaggedParserAtomIndex getAtom(size_t index) const;
AbstractScopePtr firstScope() const {
MOZ_ASSERT(firstScopeIndex.isSome());
return getScope(*firstScopeIndex);
}
};
[[nodiscard]] bool EmitScriptThingsVector(
JSContext* cx, const CompilationAtomCache& atomCache,
const CompilationStencil& stencil, CompilationGCOutput& gcOutput,
mozilla::Span<const TaggedScriptThingIndex> things,
mozilla::Span<JS::GCCellPtr> output);
struct CGTryNoteList {
Vector<TryNote, 0> list;
explicit CGTryNoteList(FrontendContext* fc) : list(fc) {}
[[nodiscard]] bool append(TryNoteKind kind, uint32_t stackDepth,
BytecodeOffset start, BytecodeOffset end);
mozilla::Span<const TryNote> span() const {
return {list.begin(), list.length()};
}
size_t length() const { return list.length(); }
};
struct CGScopeNoteList {
Vector<ScopeNote, 0> list;
explicit CGScopeNoteList(FrontendContext* fc) : list(fc) {}
[[nodiscard]] bool append(GCThingIndex scopeIndex, BytecodeOffset offset,
uint32_t parent);
void recordEnd(uint32_t index, BytecodeOffset offset);
void recordEndFunctionBodyVar(uint32_t index);
mozilla::Span<const ScopeNote> span() const {
return {list.begin(), list.length()};
}
size_t length() const { return list.length(); }
private:
void recordEndImpl(uint32_t index, uint32_t offset);
};
struct CGResumeOffsetList {
Vector<uint32_t, 0> list;
explicit CGResumeOffsetList(FrontendContext* fc) : list(fc) {}
[[nodiscard]] bool append(uint32_t offset) { return list.append(offset); }
mozilla::Span<const uint32_t> span() const {
return {list.begin(), list.length()};
}
size_t length() const { return list.length(); }
};
static constexpr size_t MaxBytecodeLength = INT32_MAX;
static constexpr size_t MaxSrcNotesLength = INT32_MAX;
// Have a few inline elements, so as to avoid heap allocation for tiny
typedef Vector<jsbytecode, 64> BytecodeVector;
typedef Vector<js::SrcNote, 64> SrcNotesVector;
// Bytecode and all data directly associated with specific opcode/index inside
// bytecode is stored in this class.
class BytecodeSection {
public:
BytecodeSection(FrontendContext* fc, uint32_t lineNum,
JS::LimitedColumnNumberOneOrigin column);
// ---- Bytecode ----
BytecodeVector& code() { return code_; }
const BytecodeVector& code() const { return code_; }
jsbytecode* code(BytecodeOffset offset) {
return code_.begin() + offset.value();
}
BytecodeOffset offset() const {
return BytecodeOffset(code_.end() - code_.begin());
}
// ---- Source notes ----
SrcNotesVector& notes() { return notes_; }
const SrcNotesVector& notes() const { return notes_; }
BytecodeOffset lastNoteOffset() const { return lastNoteOffset_; }
void setLastNoteOffset(BytecodeOffset offset) { lastNoteOffset_ = offset; }
// ---- Jump ----
BytecodeOffset lastTargetOffset() const { return lastTarget_.offset; }
void setLastTargetOffset(BytecodeOffset offset) {
lastTarget_.offset = offset;
}
// ---- Stack ----
int32_t stackDepth() const { return stackDepth_; }
void setStackDepth(int32_t depth) { stackDepth_ = depth; }
uint32_t maxStackDepth() const { return maxStackDepth_; }
void updateDepth(JSOp op, BytecodeOffset target);
// ---- Try notes ----
CGTryNoteList& tryNoteList() { return tryNoteList_; };
const CGTryNoteList& tryNoteList() const { return tryNoteList_; };
// ---- Scope ----
CGScopeNoteList& scopeNoteList() { return scopeNoteList_; };
const CGScopeNoteList& scopeNoteList() const { return scopeNoteList_; };
// ---- Generator ----
CGResumeOffsetList& resumeOffsetList() { return resumeOffsetList_; }
const CGResumeOffsetList& resumeOffsetList() const {
return resumeOffsetList_;
}
uint32_t numYields() const { return numYields_; }
void addNumYields() { numYields_++; }
// ---- Line and column ----
uint32_t currentLine() const { return currentLine_; }
JS::LimitedColumnNumberOneOrigin lastColumn() const { return lastColumn_; }
void setCurrentLine(uint32_t line, uint32_t sourceOffset) {
currentLine_ = line;
lastColumn_ = JS::LimitedColumnNumberOneOrigin();
lastSourceOffset_ = sourceOffset;
}
void setLastColumn(JS::LimitedColumnNumberOneOrigin column, uint32_t offset) {
lastColumn_ = column;
lastSourceOffset_ = offset;
}
void updateSeparatorPosition() {
lastSeparatorCodeOffset_ = code().length();
lastSeparatorSourceOffset_ = lastSourceOffset_;
lastSeparatorLine_ = currentLine_;
lastSeparatorColumn_ = lastColumn_;
}
void updateSeparatorPositionIfPresent() {
if (lastSeparatorCodeOffset_ == code().length()) {
lastSeparatorSourceOffset_ = lastSourceOffset_;
lastSeparatorLine_ = currentLine_;
lastSeparatorColumn_ = lastColumn_;
}
}
bool isDuplicateLocation() const {
return lastSeparatorLine_ == currentLine_ &&
lastSeparatorColumn_ == lastColumn_;
}
bool atSeparator(uint32_t offset) const {
return lastSeparatorSourceOffset_ == offset;
}
// ---- JIT ----
uint32_t numICEntries() const { return numICEntries_; }
void incrementNumICEntries() {
MOZ_ASSERT(numICEntries_ != UINT32_MAX, "Shouldn't overflow");
numICEntries_++;
}
void setNumICEntries(uint32_t entries) { numICEntries_ = entries; }
private:
// ---- Bytecode ----
// Bytecode.
BytecodeVector code_;
// ---- Source notes ----
// Source notes
SrcNotesVector notes_;
// Code offset for last source note
BytecodeOffset lastNoteOffset_;
// ---- Jump ----
// Last jump target emitted.
JumpTarget lastTarget_;
// ---- Stack ----
// Maximum number of expression stack slots so far.
uint32_t maxStackDepth_ = 0;
// Current stack depth in script frame.
int32_t stackDepth_ = 0;
// ---- Try notes ----
// List of emitted try notes.
CGTryNoteList tryNoteList_;
// ---- Scope ----
// List of emitted block scope notes.
CGScopeNoteList scopeNoteList_;
// ---- Generator ----
// Certain ops (yield, await) have an entry in the script's resumeOffsets
// list. This can be used to map from the op's resumeIndex to the bytecode
// offset of the next pc. This indirection makes it easy to resume in the JIT
// (because BaselineScript stores a resumeIndex => native code array).
CGResumeOffsetList resumeOffsetList_;
// Number of yield instructions emitted. Does not include JSOp::Await.
uint32_t numYields_ = 0;
// ---- Line and column ----
// Line number for srcnotes.
//
// WARNING: If this becomes out of sync with already-emitted srcnotes,
// we can get undefined behavior.
uint32_t currentLine_;
// Column index in UTF-16 code units on currentLine_ of last
// SrcNoteType::ColSpan-annotated opcode.
//
// WARNING: If this becomes out of sync with already-emitted srcnotes,
// we can get undefined behavior.
JS::LimitedColumnNumberOneOrigin lastColumn_;
// The last code unit used for srcnotes.
uint32_t lastSourceOffset_ = 0;
// The offset, line and column numbers of the last opcode for the
// breakpoint for step execution.
uint32_t lastSeparatorCodeOffset_ = 0;
uint32_t lastSeparatorSourceOffset_ = 0;
uint32_t lastSeparatorLine_ = 0;
JS::LimitedColumnNumberOneOrigin lastSeparatorColumn_;
// ---- JIT ----
// Number of ICEntries in the script. There's one ICEntry for each JOF_IC op
// and, if the script is a function, for |this| and each formal argument.
uint32_t numICEntries_ = 0;
};
// Data that is not directly associated with specific opcode/index inside
// bytecode, but referred from bytecode is stored in this class.
class PerScriptData {
public:
PerScriptData(FrontendContext* fc,
frontend::CompilationState& compilationState);
[[nodiscard]] bool init(FrontendContext* fc);
GCThingList& gcThingList() { return gcThingList_; }
const GCThingList& gcThingList() const { return gcThingList_; }
PooledMapPtr<AtomIndexMap>& atomIndices() { return atomIndices_; }
const PooledMapPtr<AtomIndexMap>& atomIndices() const { return atomIndices_; }
private:
// List of emitted scopes/objects/bigints.
GCThingList gcThingList_;
// Map from atom to index.
PooledMapPtr<AtomIndexMap> atomIndices_;
};
} /* namespace frontend */
} /* namespace js */
#endif /* frontend_BytecodeSection_h */