Source code
Revision control
Copy as Markdown
Other Tools
/* -*- 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 jit_arm_Assembler_arm_h
#define jit_arm_Assembler_arm_h
#include "mozilla/Attributes.h"
#include "mozilla/MathAlgorithms.h"
#include <algorithm>
#include <iterator>
#include <type_traits>
#include "jit/arm/Architecture-arm.h"
#include "jit/arm/disasm/Disasm-arm.h"
#include "jit/CompactBuffer.h"
#include "jit/JitCode.h"
#include "jit/shared/Assembler-shared.h"
#include "jit/shared/Disassembler-shared.h"
#include "jit/shared/IonAssemblerBufferWithConstantPools.h"
#include "wasm/WasmTypeDecls.h"
union PoolHintPun;
namespace js {
namespace jit {
using LiteralDoc = DisassemblerSpew::LiteralDoc;
using LabelDoc = DisassemblerSpew::LabelDoc;
// NOTE: there are duplicates in this list! Sometimes we want to specifically
// refer to the link register as a link register (bl lr is much clearer than bl
// r14). HOWEVER, this register can easily be a gpr when it is not busy holding
// the return address.
static constexpr Register r0{Registers::r0};
static constexpr Register r1{Registers::r1};
static constexpr Register r2{Registers::r2};
static constexpr Register r3{Registers::r3};
static constexpr Register r4{Registers::r4};
static constexpr Register r5{Registers::r5};
static constexpr Register r6{Registers::r6};
static constexpr Register r7{Registers::r7};
static constexpr Register r8{Registers::r8};
static constexpr Register r9{Registers::r9};
static constexpr Register r10{Registers::r10};
static constexpr Register r11{Registers::r11};
static constexpr Register r12{Registers::ip};
static constexpr Register ip{Registers::ip};
static constexpr Register sp{Registers::sp};
static constexpr Register r14{Registers::lr};
static constexpr Register lr{Registers::lr};
static constexpr Register pc{Registers::pc};
static constexpr Register ScratchRegister{Registers::ip};
// Helper class for ScratchRegister usage. Asserts that only one piece
// of code thinks it has exclusive ownership of the scratch register.
struct ScratchRegisterScope : public AutoRegisterScope {
explicit ScratchRegisterScope(MacroAssembler& masm)
: AutoRegisterScope(masm, ScratchRegister) {}
};
struct SecondScratchRegisterScope : public AutoRegisterScope {
explicit SecondScratchRegisterScope(MacroAssembler& masm);
};
class MOZ_RAII AutoNonDefaultSecondScratchRegister {
public:
explicit AutoNonDefaultSecondScratchRegister(MacroAssembler& masm,
Register reg);
~AutoNonDefaultSecondScratchRegister();
private:
Register prevSecondScratch_;
MacroAssembler& masm_;
};
static constexpr Register OsrFrameReg = r3;
static constexpr Register CallTempReg0 = r5;
static constexpr Register CallTempReg1 = r6;
static constexpr Register CallTempReg2 = r7;
static constexpr Register CallTempReg3 = r8;
static constexpr Register CallTempReg4 = r0;
static constexpr Register CallTempReg5 = r1;
static constexpr Register IntArgReg0 = r0;
static constexpr Register IntArgReg1 = r1;
static constexpr Register IntArgReg2 = r2;
static constexpr Register IntArgReg3 = r3;
static constexpr Register HeapReg = r10;
static constexpr Register CallTempNonArgRegs[] = {r5, r6, r7, r8};
static const uint32_t NumCallTempNonArgRegs = std::size(CallTempNonArgRegs);
// These register assignments for the 64-bit atomic ops are frequently too
// constraining, but we have no way of expressing looser constraints to the
// register allocator.
// CompareExchange: Any two odd/even pairs would do for `new` and `out`, and any
// pair would do for `old`, so long as none of them overlap.
static constexpr Register CmpXchgOldLo = r4;
static constexpr Register CmpXchgOldHi = r5;
static constexpr Register64 CmpXchgOld64 =
Register64(CmpXchgOldHi, CmpXchgOldLo);
static constexpr Register CmpXchgNewLo = IntArgReg2;
static constexpr Register CmpXchgNewHi = IntArgReg3;
static constexpr Register64 CmpXchgNew64 =
Register64(CmpXchgNewHi, CmpXchgNewLo);
static constexpr Register CmpXchgOutLo = IntArgReg0;
static constexpr Register CmpXchgOutHi = IntArgReg1;
static constexpr Register64 CmpXchgOut64 =
Register64(CmpXchgOutHi, CmpXchgOutLo);
// Exchange: Any two non-equal odd/even pairs would do for `new` and `out`.
static constexpr Register XchgNewLo = IntArgReg2;
static constexpr Register XchgNewHi = IntArgReg3;
static constexpr Register64 XchgNew64 = Register64(XchgNewHi, XchgNewLo);
static constexpr Register XchgOutLo = IntArgReg0;
static constexpr Register XchgOutHi = IntArgReg1;
// Atomic rmw operations: Any two odd/even pairs would do for `tmp` and `out`,
// and any pair would do for `val`, so long as none of them overlap.
static constexpr Register FetchOpValLo = r4;
static constexpr Register FetchOpValHi = r5;
static constexpr Register64 FetchOpVal64 =
Register64(FetchOpValHi, FetchOpValLo);
static constexpr Register FetchOpTmpLo = IntArgReg2;
static constexpr Register FetchOpTmpHi = IntArgReg3;
static constexpr Register64 FetchOpTmp64 =
Register64(FetchOpTmpHi, FetchOpTmpLo);
static constexpr Register FetchOpOutLo = IntArgReg0;
static constexpr Register FetchOpOutHi = IntArgReg1;
static constexpr Register64 FetchOpOut64 =
Register64(FetchOpOutHi, FetchOpOutLo);
class ABIArgGenerator {
unsigned intRegIndex_;
unsigned floatRegIndex_;
uint32_t stackOffset_;
ABIArg current_;
// ARM can either use HardFp (use float registers for float arguments), or
// SoftFp (use general registers for float arguments) ABI. We keep this
// switch as a runtime switch because wasm always use the HardFp back-end
// while the calls to native functions have to use the one provided by the
// system.
bool useHardFp_;
ABIArg softNext(MIRType argType);
ABIArg hardNext(MIRType argType);
public:
ABIArgGenerator();
void setUseHardFp(bool useHardFp) {
MOZ_ASSERT(intRegIndex_ == 0 && floatRegIndex_ == 0);
useHardFp_ = useHardFp;
}
ABIArg next(MIRType argType);
ABIArg& current() { return current_; }
uint32_t stackBytesConsumedSoFar() const { return stackOffset_; }
void increaseStackOffset(uint32_t bytes) { stackOffset_ += bytes; }
};
bool IsUnaligned(const wasm::MemoryAccessDesc& access);
// These registers may be volatile or nonvolatile.
static constexpr Register ABINonArgReg0 = r4;
static constexpr Register ABINonArgReg1 = r5;
static constexpr Register ABINonArgReg2 = r6;
static constexpr Register ABINonArgReg3 = r7;
// This register may be volatile or nonvolatile. Avoid d15 which is the
// ScratchDoubleReg_.
static constexpr FloatRegister ABINonArgDoubleReg{FloatRegisters::d8,
VFPRegister::Double};
// These registers may be volatile or nonvolatile.
// Note: these three registers are all guaranteed to be different
static constexpr Register ABINonArgReturnReg0 = r4;
static constexpr Register ABINonArgReturnReg1 = r5;
static constexpr Register ABINonVolatileReg = r6;
// This register is guaranteed to be clobberable during the prologue and
// epilogue of an ABI call which must preserve both ABI argument, return
// and non-volatile registers.
static constexpr Register ABINonArgReturnVolatileReg = lr;
// Instance pointer argument register for WebAssembly functions. This must not
// alias any other register used for passing function arguments or return
// values. Preserved by WebAssembly functions.
static constexpr Register InstanceReg = r9;
// Registers used for wasm table calls. These registers must be disjoint
// from the ABI argument registers, InstanceReg and each other.
static constexpr Register WasmTableCallScratchReg0 = ABINonArgReg0;
static constexpr Register WasmTableCallScratchReg1 = ABINonArgReg1;
static constexpr Register WasmTableCallSigReg = ABINonArgReg2;
static constexpr Register WasmTableCallIndexReg = ABINonArgReg3;
// Registers used for ref calls.
static constexpr Register WasmCallRefCallScratchReg0 = ABINonArgReg0;
static constexpr Register WasmCallRefCallScratchReg1 = ABINonArgReg1;
static constexpr Register WasmCallRefReg = ABINonArgReg3;
// Registers used for wasm tail calls operations.
static constexpr Register WasmTailCallInstanceScratchReg = ABINonArgReg1;
static constexpr Register WasmTailCallRAScratchReg = lr;
static constexpr Register WasmTailCallFPScratchReg = ABINonArgReg3;
// Register used as a scratch along the return path in the fast js -> wasm stub
// code. This must not overlap ReturnReg, JSReturnOperand, or InstanceReg.
// It must be a volatile register.
static constexpr Register WasmJitEntryReturnScratch = r5;
static constexpr Register PreBarrierReg = r1;
static constexpr Register InterpreterPCReg = r9;
static constexpr Register InvalidReg{Registers::invalid_reg};
static constexpr FloatRegister InvalidFloatReg;
static constexpr Register JSReturnReg_Type = r3;
static constexpr Register JSReturnReg_Data = r2;
static constexpr Register StackPointer = sp;
static constexpr Register FramePointer = r11;
static constexpr Register ReturnReg = r0;
static constexpr Register64 ReturnReg64(r1, r0);
// The attribute '__value_in_regs' alters the calling convention of a function
// so that a structure of up to four elements can be returned via the argument
// registers rather than being written to memory.
static constexpr Register ReturnRegVal0 = IntArgReg0;
static constexpr Register ReturnRegVal1 = IntArgReg1;
static constexpr Register ReturnRegVal2 = IntArgReg2;
static constexpr Register ReturnRegVal3 = IntArgReg3;
static constexpr FloatRegister ReturnFloat32Reg = {FloatRegisters::d0,
VFPRegister::Single};
static constexpr FloatRegister ReturnDoubleReg = {FloatRegisters::d0,
VFPRegister::Double};
static constexpr FloatRegister ReturnSimd128Reg = InvalidFloatReg;
static constexpr FloatRegister ScratchFloat32Reg_ = {FloatRegisters::s30,
VFPRegister::Single};
static constexpr FloatRegister ScratchDoubleReg_ = {FloatRegisters::d15,
VFPRegister::Double};
static constexpr FloatRegister ScratchSimd128Reg = InvalidFloatReg;
static constexpr FloatRegister ScratchUIntReg = {FloatRegisters::d15,
VFPRegister::UInt};
static constexpr FloatRegister ScratchIntReg = {FloatRegisters::d15,
VFPRegister::Int};
// Do not reference ScratchFloat32Reg_ directly, use ScratchFloat32Scope
// instead.
struct ScratchFloat32Scope : public AutoFloatRegisterScope {
explicit ScratchFloat32Scope(MacroAssembler& masm)
: AutoFloatRegisterScope(masm, ScratchFloat32Reg_) {}
};
// Do not reference ScratchDoubleReg_ directly, use ScratchDoubleScope instead.
struct ScratchDoubleScope : public AutoFloatRegisterScope {
explicit ScratchDoubleScope(MacroAssembler& masm)
: AutoFloatRegisterScope(masm, ScratchDoubleReg_) {}
};
// Registers used by RegExpMatcher and RegExpExecMatch stubs (do not use
// JSReturnOperand).
static constexpr Register RegExpMatcherRegExpReg = CallTempReg0;
static constexpr Register RegExpMatcherStringReg = CallTempReg1;
static constexpr Register RegExpMatcherLastIndexReg = CallTempReg2;
// Registers used by RegExpExecTest stub (do not use ReturnReg).
static constexpr Register RegExpExecTestRegExpReg = CallTempReg0;
static constexpr Register RegExpExecTestStringReg = CallTempReg1;
// Registers used by RegExpSearcher stub (do not use ReturnReg).
static constexpr Register RegExpSearcherRegExpReg = CallTempReg0;
static constexpr Register RegExpSearcherStringReg = CallTempReg1;
static constexpr Register RegExpSearcherLastIndexReg = CallTempReg2;
static constexpr FloatRegister d0 = {FloatRegisters::d0, VFPRegister::Double};
static constexpr FloatRegister d1 = {FloatRegisters::d1, VFPRegister::Double};
static constexpr FloatRegister d2 = {FloatRegisters::d2, VFPRegister::Double};
static constexpr FloatRegister d3 = {FloatRegisters::d3, VFPRegister::Double};
static constexpr FloatRegister d4 = {FloatRegisters::d4, VFPRegister::Double};
static constexpr FloatRegister d5 = {FloatRegisters::d5, VFPRegister::Double};
static constexpr FloatRegister d6 = {FloatRegisters::d6, VFPRegister::Double};
static constexpr FloatRegister d7 = {FloatRegisters::d7, VFPRegister::Double};
static constexpr FloatRegister d8 = {FloatRegisters::d8, VFPRegister::Double};
static constexpr FloatRegister d9 = {FloatRegisters::d9, VFPRegister::Double};
static constexpr FloatRegister d10 = {FloatRegisters::d10, VFPRegister::Double};
static constexpr FloatRegister d11 = {FloatRegisters::d11, VFPRegister::Double};
static constexpr FloatRegister d12 = {FloatRegisters::d12, VFPRegister::Double};
static constexpr FloatRegister d13 = {FloatRegisters::d13, VFPRegister::Double};
static constexpr FloatRegister d14 = {FloatRegisters::d14, VFPRegister::Double};
static constexpr FloatRegister d15 = {FloatRegisters::d15, VFPRegister::Double};
// For maximal awesomeness, 8 should be sufficent. ldrd/strd (dual-register
// load/store) operate in a single cycle when the address they are dealing with
// is 8 byte aligned. Also, the ARM abi wants the stack to be 8 byte aligned at
// function boundaries. I'm trying to make sure this is always true.
static constexpr uint32_t ABIStackAlignment = 8;
static constexpr uint32_t CodeAlignment = 8;
static constexpr uint32_t JitStackAlignment = 8;
static constexpr uint32_t JitStackValueAlignment =
JitStackAlignment / sizeof(Value);
static_assert(JitStackAlignment % sizeof(Value) == 0 &&
JitStackValueAlignment >= 1,
"Stack alignment should be a non-zero multiple of sizeof(Value)");
static constexpr uint32_t SimdMemoryAlignment = 8;
static_assert(CodeAlignment % SimdMemoryAlignment == 0,
"Code alignment should be larger than any of the alignments "
"which are used for "
"the constant sections of the code buffer. Thus it should be "
"larger than the "
"alignment for SIMD constants.");
static_assert(JitStackAlignment % SimdMemoryAlignment == 0,
"Stack alignment should be larger than any of the alignments "
"which are used for "
"spilled values. Thus it should be larger than the alignment "
"for SIMD accesses.");
static const uint32_t WasmStackAlignment = SimdMemoryAlignment;
static const uint32_t WasmTrapInstructionLength = 4;
// See comments in wasm::GenerateFunctionPrologue. The difference between these
// is the size of the largest callable prologue on the platform.
static constexpr uint32_t WasmCheckedCallEntryOffset = 0u;
static const Scale ScalePointer = TimesFour;
class Instruction;
class InstBranchImm;
uint32_t RM(Register r);
uint32_t RS(Register r);
uint32_t RD(Register r);
uint32_t RT(Register r);
uint32_t RN(Register r);
uint32_t maybeRD(Register r);
uint32_t maybeRT(Register r);
uint32_t maybeRN(Register r);
Register toRN(Instruction i);
Register toRM(Instruction i);
Register toRD(Instruction i);
Register toR(Instruction i);
class VFPRegister;
uint32_t VD(VFPRegister vr);
uint32_t VN(VFPRegister vr);
uint32_t VM(VFPRegister vr);
// For being passed into the generic vfp instruction generator when there is an
// instruction that only takes two registers.
static constexpr VFPRegister NoVFPRegister(VFPRegister::Double, 0, false, true);
struct ImmTag : public Imm32 {
explicit ImmTag(JSValueTag mask) : Imm32(int32_t(mask)) {}
};
struct ImmType : public ImmTag {
explicit ImmType(JSValueType type) : ImmTag(JSVAL_TYPE_TO_TAG(type)) {}
};
enum Index {
Offset = 0 << 21 | 1 << 24,
PreIndex = 1 << 21 | 1 << 24,
PostIndex = 0 << 21 | 0 << 24
// The docs were rather unclear on this. It sounds like
// 1 << 21 | 0 << 24 encodes dtrt.
};
enum IsImmOp2_ { IsImmOp2 = 1 << 25, IsNotImmOp2 = 0 << 25 };
enum IsImmDTR_ { IsImmDTR = 0 << 25, IsNotImmDTR = 1 << 25 };
// For the extra memory operations, ldrd, ldrsb, ldrh.
enum IsImmEDTR_ { IsImmEDTR = 1 << 22, IsNotImmEDTR = 0 << 22 };
enum ShiftType {
LSL = 0, // << 5
LSR = 1, // << 5
ASR = 2, // << 5
ROR = 3, // << 5
RRX = ROR // RRX is encoded as ROR with a 0 offset.
};
// Modes for STM/LDM. Names are the suffixes applied to the instruction.
enum DTMMode {
A = 0 << 24, // empty / after
B = 1 << 24, // full / before
D = 0 << 23, // decrement
I = 1 << 23, // increment
DA = D | A,
DB = D | B,
IA = I | A,
IB = I | B
};
enum DTMWriteBack { WriteBack = 1 << 21, NoWriteBack = 0 << 21 };
// Condition code updating mode.
enum SBit {
SetCC = 1 << 20, // Set condition code.
LeaveCC = 0 << 20 // Leave condition code unchanged.
};
enum LoadStore { IsLoad = 1 << 20, IsStore = 0 << 20 };
// You almost never want to use this directly. Instead, you wantto pass in a
// signed constant, and let this bit be implicitly set for you. This is however,
// necessary if we want a negative index.
enum IsUp_ { IsUp = 1 << 23, IsDown = 0 << 23 };
enum ALUOp {
OpMov = 0xd << 21,
OpMvn = 0xf << 21,
OpAnd = 0x0 << 21,
OpBic = 0xe << 21,
OpEor = 0x1 << 21,
OpOrr = 0xc << 21,
OpAdc = 0x5 << 21,
OpAdd = 0x4 << 21,
OpSbc = 0x6 << 21,
OpSub = 0x2 << 21,
OpRsb = 0x3 << 21,
OpRsc = 0x7 << 21,
OpCmn = 0xb << 21,
OpCmp = 0xa << 21,
OpTeq = 0x9 << 21,
OpTst = 0x8 << 21,
OpInvalid = -1
};
enum MULOp {
OpmMul = 0 << 21,
OpmMla = 1 << 21,
OpmUmaal = 2 << 21,
OpmMls = 3 << 21,
OpmUmull = 4 << 21,
OpmUmlal = 5 << 21,
OpmSmull = 6 << 21,
OpmSmlal = 7 << 21
};
enum BranchTag {
OpB = 0x0a000000,
OpBMask = 0x0f000000,
OpBDestMask = 0x00ffffff,
OpBl = 0x0b000000,
OpBlx = 0x012fff30,
OpBx = 0x012fff10
};
// Just like ALUOp, but for the vfp instruction set.
enum VFPOp {
OpvMul = 0x2 << 20,
OpvAdd = 0x3 << 20,
OpvSub = 0x3 << 20 | 0x1 << 6,
OpvDiv = 0x8 << 20,
OpvMov = 0xB << 20 | 0x1 << 6,
OpvAbs = 0xB << 20 | 0x3 << 6,
OpvNeg = 0xB << 20 | 0x1 << 6 | 0x1 << 16,
OpvSqrt = 0xB << 20 | 0x3 << 6 | 0x1 << 16,
OpvCmp = 0xB << 20 | 0x1 << 6 | 0x4 << 16,
OpvCmpz = 0xB << 20 | 0x1 << 6 | 0x5 << 16
};
// Negate the operation, AND negate the immediate that we were passed in.
ALUOp ALUNeg(ALUOp op, Register dest, Register scratch, Imm32* imm,
Register* negDest);
bool can_dbl(ALUOp op);
bool condsAreSafe(ALUOp op);
// If there is a variant of op that has a dest (think cmp/sub) return that
// variant of it.
ALUOp getDestVariant(ALUOp op);
static constexpr ValueOperand JSReturnOperand{JSReturnReg_Type,
JSReturnReg_Data};
static const ValueOperand softfpReturnOperand = ValueOperand(r1, r0);
// All of these classes exist solely to shuffle data into the various operands.
// For example Operand2 can be an imm8, a register-shifted-by-a-constant or a
// register-shifted-by-a-register. We represent this in C++ by having a base
// class Operand2, which just stores the 32 bits of data as they will be encoded
// in the instruction. You cannot directly create an Operand2 since it is
// tricky, and not entirely sane to do so. Instead, you create one of its child
// classes, e.g. Imm8. Imm8's constructor takes a single integer argument. Imm8
// will verify that its argument can be encoded as an ARM 12 bit imm8, encode it
// using an Imm8data, and finally call its parent's (Operand2) constructor with
// the Imm8data. The Operand2 constructor will then call the Imm8data's encode()
// function to extract the raw bits from it.
//
// In the future, we should be able to extract data from the Operand2 by asking
// it for its component Imm8data structures. The reason this is so horribly
// round-about is we wanted to have Imm8 and RegisterShiftedRegister inherit
// directly from Operand2 but have all of them take up only a single word of
// storage. We also wanted to avoid passing around raw integers at all since
// they are error prone.
class Op2Reg;
class O2RegImmShift;
class O2RegRegShift;
namespace datastore {
class Reg {
// The "second register".
uint32_t rm_ : 4;
// Do we get another register for shifting.
uint32_t rrs_ : 1;
uint32_t type_ : 2;
// We'd like this to be a more sensible encoding, but that would need to be
// a struct and that would not pack :(
uint32_t shiftAmount_ : 5;
protected:
// Mark as a protected field to avoid unused private field warnings.
uint32_t pad_ : 20;
public:
Reg(uint32_t rm, ShiftType type, uint32_t rsr, uint32_t shiftAmount)
: rm_(rm), rrs_(rsr), type_(type), shiftAmount_(shiftAmount), pad_(0) {}
explicit Reg(const Op2Reg& op) { memcpy(this, &op, sizeof(*this)); }
uint32_t shiftAmount() const { return shiftAmount_; }
uint32_t encode() const {
return rm_ | (rrs_ << 4) | (type_ << 5) | (shiftAmount_ << 7);
}
};
// Op2 has a mode labelled "<imm8m>", which is arm's magical immediate encoding.
// Some instructions actually get 8 bits of data, which is called Imm8Data
// below. These should have edit distance > 1, but this is how it is for now.
class Imm8mData {
uint32_t data_ : 8;
uint32_t rot_ : 4;
protected:
// Mark as a protected field to avoid unused private field warnings.
uint32_t buff_ : 19;
private:
// Throw in an extra bit that will be 1 if we can't encode this properly.
// if we can encode it properly, a simple "|" will still suffice to meld it
// into the instruction.
uint32_t invalid_ : 1;
public:
// Default constructor makes an invalid immediate.
Imm8mData() : data_(0xff), rot_(0xf), buff_(0), invalid_(true) {}
Imm8mData(uint32_t data, uint32_t rot)
: data_(data), rot_(rot), buff_(0), invalid_(false) {
MOZ_ASSERT(data == data_);
MOZ_ASSERT(rot == rot_);
}
bool invalid() const { return invalid_; }
uint32_t encode() const {
MOZ_ASSERT(!invalid_);
return data_ | (rot_ << 8);
};
};
class Imm8Data {
uint32_t imm4L_ : 4;
protected:
// Mark as a protected field to avoid unused private field warnings.
uint32_t pad_ : 4;
private:
uint32_t imm4H_ : 4;
public:
explicit Imm8Data(uint32_t imm) : imm4L_(imm & 0xf), imm4H_(imm >> 4) {
MOZ_ASSERT(imm <= 0xff);
}
uint32_t encode() const { return imm4L_ | (imm4H_ << 8); };
};
// VLDR/VSTR take an 8 bit offset, which is implicitly left shifted by 2.
class Imm8VFPOffData {
uint32_t data_;
public:
explicit Imm8VFPOffData(uint32_t imm) : data_(imm) {
MOZ_ASSERT((imm & ~(0xff)) == 0);
}
uint32_t encode() const { return data_; };
};
// ARM can magically encode 256 very special immediates to be moved into a
// register.
struct Imm8VFPImmData {
// This structure's members are public and it has no constructor to
// initialize them, for a very special reason. Were this structure to
// have a constructor, the initialization for DoubleEncoder's internal
// table (see below) would require a rather large static constructor on
// some of our supported compilers. The known solution to this is to mark
// the constructor constexpr, but, again, some of our supported
// compilers don't support constexpr! So we are reduced to public
// members and eschewing a constructor in hopes that the initialization
// of DoubleEncoder's table is correct.
uint32_t imm4L : 4;
uint32_t imm4H : 4;
int32_t isInvalid : 24;
uint32_t encode() const {
// This assert is an attempting at ensuring that we don't create random
// instances of this structure and then asking to encode() it.
MOZ_ASSERT(isInvalid == 0);
return imm4L | (imm4H << 16);
};
};
class Imm12Data {
uint32_t data_ : 12;
public:
explicit Imm12Data(uint32_t imm) : data_(imm) { MOZ_ASSERT(data_ == imm); }
uint32_t encode() const { return data_; }
};
class RIS {
uint32_t shiftAmount_ : 5;
public:
explicit RIS(uint32_t imm) : shiftAmount_(imm) {
MOZ_ASSERT(shiftAmount_ == imm);
}
explicit RIS(Reg r) : shiftAmount_(r.shiftAmount()) {}
uint32_t encode() const { return shiftAmount_; }
};
class RRS {
protected:
// Mark as a protected field to avoid unused private field warnings.
uint32_t mustZero_ : 1;
private:
// The register that holds the shift amount.
uint32_t rs_ : 4;
public:
explicit RRS(uint32_t rs) : rs_(rs) { MOZ_ASSERT(rs_ == rs); }
uint32_t encode() const { return rs_ << 1; }
};
} // namespace datastore
class MacroAssemblerARM;
class Operand;
class Operand2 {
friend class Operand;
friend class MacroAssemblerARM;
friend class InstALU;
uint32_t oper_ : 31;
uint32_t invalid_ : 1;
protected:
explicit Operand2(datastore::Imm8mData base)
: oper_(base.invalid() ? -1 : (base.encode() | uint32_t(IsImmOp2))),
invalid_(base.invalid()) {}
explicit Operand2(datastore::Reg base)
: oper_(base.encode() | uint32_t(IsNotImmOp2)), invalid_(false) {}
private:
explicit Operand2(uint32_t blob) : oper_(blob), invalid_(false) {}
public:
bool isO2Reg() const { return !(oper_ & IsImmOp2); }
Op2Reg toOp2Reg() const;
bool isImm8() const { return oper_ & IsImmOp2; }
bool invalid() const { return invalid_; }
uint32_t encode() const { return oper_; }
};
class Imm8 : public Operand2 {
public:
explicit Imm8(uint32_t imm) : Operand2(EncodeImm(imm)) {}
static datastore::Imm8mData EncodeImm(uint32_t imm) {
// RotateLeft below may not be called with a shift of zero.
if (imm <= 0xFF) {
return datastore::Imm8mData(imm, 0);
}
// An encodable integer has a maximum of 8 contiguous set bits,
// with an optional wrapped left rotation to even bit positions.
for (int rot = 1; rot < 16; rot++) {
uint32_t rotimm = mozilla::RotateLeft(imm, rot * 2);
if (rotimm <= 0xFF) {
return datastore::Imm8mData(rotimm, rot);
}
}
return datastore::Imm8mData();
}
// Pair template?
struct TwoImm8mData {
datastore::Imm8mData fst_, snd_;
TwoImm8mData() = default;
TwoImm8mData(datastore::Imm8mData fst, datastore::Imm8mData snd)
: fst_(fst), snd_(snd) {}
datastore::Imm8mData fst() const { return fst_; }
datastore::Imm8mData snd() const { return snd_; }
};
static TwoImm8mData EncodeTwoImms(uint32_t);
};
class Op2Reg : public Operand2 {
public:
explicit Op2Reg(Register rm, ShiftType type, datastore::RIS shiftImm)
: Operand2(datastore::Reg(rm.code(), type, 0, shiftImm.encode())) {}
explicit Op2Reg(Register rm, ShiftType type, datastore::RRS shiftReg)
: Operand2(datastore::Reg(rm.code(), type, 1, shiftReg.encode())) {}
};
static_assert(sizeof(Op2Reg) == sizeof(datastore::Reg),
"datastore::Reg(const Op2Reg&) constructor relies on Reg/Op2Reg "
"having same size");
class O2RegImmShift : public Op2Reg {
public:
explicit O2RegImmShift(Register rn, ShiftType type, uint32_t shift)
: Op2Reg(rn, type, datastore::RIS(shift)) {}
};
class O2RegRegShift : public Op2Reg {
public:
explicit O2RegRegShift(Register rn, ShiftType type, Register rs)
: Op2Reg(rn, type, datastore::RRS(rs.code())) {}
};
O2RegImmShift O2Reg(Register r);
O2RegImmShift lsl(Register r, int amt);
O2RegImmShift lsr(Register r, int amt);
O2RegImmShift asr(Register r, int amt);
O2RegImmShift rol(Register r, int amt);
O2RegImmShift ror(Register r, int amt);
O2RegRegShift lsl(Register r, Register amt);
O2RegRegShift lsr(Register r, Register amt);
O2RegRegShift asr(Register r, Register amt);
O2RegRegShift ror(Register r, Register amt);
// An offset from a register to be used for ldr/str. This should include the
// sign bit, since ARM has "signed-magnitude" offsets. That is it encodes an
// unsigned offset, then the instruction specifies if the offset is positive or
// negative. The +/- bit is necessary if the instruction set wants to be able to
// have a negative register offset e.g. ldr pc, [r1,-r2];
class DtrOff {
uint32_t data_;
protected:
explicit DtrOff(datastore::Imm12Data immdata, IsUp_ iu)
: data_(immdata.encode() | uint32_t(IsImmDTR) | uint32_t(iu)) {}
explicit DtrOff(datastore::Reg reg, IsUp_ iu = IsUp)
: data_(reg.encode() | uint32_t(IsNotImmDTR) | iu) {}
public:
uint32_t encode() const { return data_; }
};
class DtrOffImm : public DtrOff {
public:
explicit DtrOffImm(int32_t imm)
: DtrOff(datastore::Imm12Data(mozilla::Abs(imm)),
imm >= 0 ? IsUp : IsDown) {
MOZ_ASSERT(mozilla::Abs(imm) < 4096);
}
};
class DtrOffReg : public DtrOff {
// These are designed to be called by a constructor of a subclass.
// Constructing the necessary RIS/RRS structures is annoying.
protected:
explicit DtrOffReg(Register rn, ShiftType type, datastore::RIS shiftImm,
IsUp_ iu = IsUp)
: DtrOff(datastore::Reg(rn.code(), type, 0, shiftImm.encode()), iu) {}
explicit DtrOffReg(Register rn, ShiftType type, datastore::RRS shiftReg,
IsUp_ iu = IsUp)
: DtrOff(datastore::Reg(rn.code(), type, 1, shiftReg.encode()), iu) {}
};
class DtrRegImmShift : public DtrOffReg {
public:
explicit DtrRegImmShift(Register rn, ShiftType type, uint32_t shift,
IsUp_ iu = IsUp)
: DtrOffReg(rn, type, datastore::RIS(shift), iu) {}
};
class DtrRegRegShift : public DtrOffReg {
public:
explicit DtrRegRegShift(Register rn, ShiftType type, Register rs,
IsUp_ iu = IsUp)
: DtrOffReg(rn, type, datastore::RRS(rs.code()), iu) {}
};
// We will frequently want to bundle a register with its offset so that we have
// an "operand" to a load instruction.
class DTRAddr {
friend class Operand;
uint32_t data_;
public:
explicit DTRAddr(Register reg, DtrOff dtr)
: data_(dtr.encode() | (reg.code() << 16)) {}
uint32_t encode() const { return data_; }
Register getBase() const { return Register::FromCode((data_ >> 16) & 0xf); }
};
// Offsets for the extended data transfer instructions:
// ldrsh, ldrd, ldrsb, etc.
class EDtrOff {
uint32_t data_;
protected:
explicit EDtrOff(datastore::Imm8Data imm8, IsUp_ iu = IsUp)
: data_(imm8.encode() | IsImmEDTR | uint32_t(iu)) {}
explicit EDtrOff(Register rm, IsUp_ iu = IsUp)
: data_(rm.code() | IsNotImmEDTR | iu) {}
public:
uint32_t encode() const { return data_; }
};
class EDtrOffImm : public EDtrOff {
public:
explicit EDtrOffImm(int32_t imm)
: EDtrOff(datastore::Imm8Data(mozilla::Abs(imm)),
(imm >= 0) ? IsUp : IsDown) {
MOZ_ASSERT(mozilla::Abs(imm) < 256);
}
};
// This is the most-derived class, since the extended data transfer instructions
// don't support any sort of modifying the "index" operand.
class EDtrOffReg : public EDtrOff {
public:
explicit EDtrOffReg(Register rm) : EDtrOff(rm) {}
};
class EDtrAddr {
uint32_t data_;
public:
explicit EDtrAddr(Register r, EDtrOff off) : data_(RN(r) | off.encode()) {}
uint32_t encode() const { return data_; }
#ifdef DEBUG
Register maybeOffsetRegister() const {
if (data_ & IsImmEDTR) {
return InvalidReg;
}
return Register::FromCode(data_ & 0xf);
}
#endif
};
class VFPOff {
uint32_t data_;
protected:
explicit VFPOff(datastore::Imm8VFPOffData imm, IsUp_ isup)
: data_(imm.encode() | uint32_t(isup)) {}
public:
uint32_t encode() const { return data_; }
};
class VFPOffImm : public VFPOff {
public:
explicit VFPOffImm(int32_t imm)
: VFPOff(datastore::Imm8VFPOffData(mozilla::Abs(imm) / 4),
imm < 0 ? IsDown : IsUp) {
MOZ_ASSERT(mozilla::Abs(imm) <= 255 * 4);
}
};
class VFPAddr {
friend class Operand;
uint32_t data_;
public:
explicit VFPAddr(Register base, VFPOff off)
: data_(RN(base) | off.encode()) {}
uint32_t encode() const { return data_; }
};
class VFPImm {
uint32_t data_;
public:
explicit VFPImm(uint32_t topWordOfDouble);
static const VFPImm One;
uint32_t encode() const { return data_; }
bool isValid() const { return data_ != (~0U); }
};
// A BOffImm is an immediate that is used for branches. Namely, it is the offset
// that will be encoded in the branch instruction. This is the only sane way of
// constructing a branch.
class BOffImm {
friend class InstBranchImm;
uint32_t data_;
public:
explicit BOffImm(int offset) : data_((offset - 8) >> 2 & 0x00ffffff) {
MOZ_ASSERT((offset & 0x3) == 0);
if (!IsInRange(offset)) {
MOZ_CRASH("BOffImm offset out of range");
}
}
explicit BOffImm() : data_(INVALID) {}
private:
explicit BOffImm(const Instruction& inst);
public:
static const uint32_t INVALID = 0x00800000;
uint32_t encode() const { return data_; }
int32_t decode() const { return ((int32_t(data_) << 8) >> 6) + 8; }
static bool IsInRange(int offset) {
if ((offset - 8) < -33554432) {
return false;
}
if ((offset - 8) > 33554428) {
return false;
}
return true;
}
bool isInvalid() const { return data_ == INVALID; }
Instruction* getDest(Instruction* src) const;
};
class Imm16 {
uint32_t lower_ : 12;
protected:
// Mark as a protected field to avoid unused private field warnings.
uint32_t pad_ : 4;
private:
uint32_t upper_ : 4;
uint32_t invalid_ : 12;
public:
explicit Imm16();
explicit Imm16(uint32_t imm);
explicit Imm16(Instruction& inst);
uint32_t encode() const { return lower_ | (upper_ << 16); }
uint32_t decode() const { return lower_ | (upper_ << 12); }
bool isInvalid() const { return invalid_; }
};
// I would preffer that these do not exist, since there are essentially no
// instructions that would ever take more than one of these, however, the MIR
// wants to only have one type of arguments to functions, so bugger.
class Operand {
// The encoding of registers is the same for OP2, DTR and EDTR yet the type
// system doesn't let us express this, so choices must be made.
public:
enum class Tag : uint8_t { OP2, MEM, FOP };
private:
uint32_t tag_ : 8;
uint32_t reg_ : 5;
int32_t offset_;
protected:
Operand(Tag tag, uint32_t regCode, int32_t offset)
: tag_(static_cast<uint32_t>(tag)), reg_(regCode), offset_(offset) {}
public:
explicit Operand(Register reg) : Operand(Tag::OP2, reg.code(), 0) {}
explicit Operand(FloatRegister freg) : Operand(Tag::FOP, freg.code(), 0) {}
explicit Operand(Register base, Imm32 off)
: Operand(Tag::MEM, base.code(), off.value) {}
explicit Operand(Register base, int32_t off)
: Operand(Tag::MEM, base.code(), off) {}
explicit Operand(const Address& addr)
: Operand(Tag::MEM, addr.base.code(), addr.offset) {}
public:
Tag tag() const { return static_cast<Tag>(tag_); }
Operand2 toOp2() const {
MOZ_ASSERT(tag() == Tag::OP2);
return O2Reg(Register::FromCode(reg_));
}
Register toReg() const {
MOZ_ASSERT(tag() == Tag::OP2);
return Register::FromCode(reg_);
}
Address toAddress() const {
MOZ_ASSERT(tag() == Tag::MEM);
return Address(Register::FromCode(reg_), offset_);
}
int32_t disp() const {
MOZ_ASSERT(tag() == Tag::MEM);
return offset_;
}
int32_t base() const {
MOZ_ASSERT(tag() == Tag::MEM);
return reg_;
}
Register baseReg() const {
MOZ_ASSERT(tag() == Tag::MEM);
return Register::FromCode(reg_);
}
DTRAddr toDTRAddr() const {
MOZ_ASSERT(tag() == Tag::MEM);
return DTRAddr(baseReg(), DtrOffImm(offset_));
}
VFPAddr toVFPAddr() const {
MOZ_ASSERT(tag() == Tag::MEM);
return VFPAddr(baseReg(), VFPOffImm(offset_));
}
};
inline Imm32 Imm64::firstHalf() const { return low(); }
inline Imm32 Imm64::secondHalf() const { return hi(); }
class InstructionIterator {
private:
Instruction* inst_;
public:
explicit InstructionIterator(Instruction* inst) : inst_(inst) {
maybeSkipAutomaticInstructions();
}
// Advances to the next intentionally-inserted instruction.
Instruction* next();
// Advances past any automatically-inserted instructions.
Instruction* maybeSkipAutomaticInstructions();
Instruction* cur() const { return inst_; }
protected:
// Advances past the given number of instruction-length bytes.
inline void advanceRaw(ptrdiff_t instructions = 1);
};
class Assembler;
typedef js::jit::AssemblerBufferWithConstantPools<1024, 4, Instruction,
Assembler>
ARMBuffer;
class Assembler : public AssemblerShared {
public:
// ARM conditional constants:
enum ARMCondition : uint32_t {
EQ = 0x00000000, // Zero
NE = 0x10000000, // Non-zero
CS = 0x20000000,
CC = 0x30000000,
MI = 0x40000000,
PL = 0x50000000,
VS = 0x60000000,
VC = 0x70000000,
HI = 0x80000000,
LS = 0x90000000,
GE = 0xa0000000,
LT = 0xb0000000,
GT = 0xc0000000,
LE = 0xd0000000,
AL = 0xe0000000
};
enum Condition : uint32_t {
Equal = EQ,
NotEqual = NE,
Above = HI,
AboveOrEqual = CS,
Below = CC,
BelowOrEqual = LS,
GreaterThan = GT,
GreaterThanOrEqual = GE,
LessThan = LT,
LessThanOrEqual = LE,
Overflow = VS,
CarrySet = CS,
CarryClear = CC,
Signed = MI,
NotSigned = PL,
Zero = EQ,
NonZero = NE,
Always = AL,
VFP_NotEqualOrUnordered = NE,
VFP_Equal = EQ,
VFP_Unordered = VS,
VFP_NotUnordered = VC,
VFP_GreaterThanOrEqualOrUnordered = CS,
VFP_GreaterThanOrEqual = GE,
VFP_GreaterThanOrUnordered = HI,
VFP_GreaterThan = GT,
VFP_LessThanOrEqualOrUnordered = LE,
VFP_LessThanOrEqual = LS,
VFP_LessThanOrUnordered = LT,
VFP_LessThan = CC // MI is valid too.
};
// Bit set when a DoubleCondition does not map to a single ARM condition.
// The macro assembler has to special-case these conditions, or else
// ConditionFromDoubleCondition will complain.
static const int DoubleConditionBitSpecial = 0x1;
enum DoubleCondition : uint32_t {
// These conditions will only evaluate to true if the comparison is
// ordered - i.e. neither operand is NaN.
DoubleOrdered = VFP_NotUnordered,
DoubleEqual = VFP_Equal,
DoubleNotEqual = VFP_NotEqualOrUnordered | DoubleConditionBitSpecial,
DoubleGreaterThan = VFP_GreaterThan,
DoubleGreaterThanOrEqual = VFP_GreaterThanOrEqual,
DoubleLessThan = VFP_LessThan,
DoubleLessThanOrEqual = VFP_LessThanOrEqual,
// If either operand is NaN, these conditions always evaluate to true.
DoubleUnordered = VFP_Unordered,
DoubleEqualOrUnordered = VFP_Equal | DoubleConditionBitSpecial,
DoubleNotEqualOrUnordered = VFP_NotEqualOrUnordered,
DoubleGreaterThanOrUnordered = VFP_GreaterThanOrUnordered,
DoubleGreaterThanOrEqualOrUnordered = VFP_GreaterThanOrEqualOrUnordered,
DoubleLessThanOrUnordered = VFP_LessThanOrUnordered,
DoubleLessThanOrEqualOrUnordered = VFP_LessThanOrEqualOrUnordered
};
Condition getCondition(uint32_t inst) {
return (Condition)(0xf0000000 & inst);
}
static inline Condition ConditionFromDoubleCondition(DoubleCondition cond) {
MOZ_ASSERT(!(cond & DoubleConditionBitSpecial));
return static_cast<Condition>(cond);
}
enum BarrierOption {
BarrierSY = 15, // Full system barrier
BarrierST = 14 // StoreStore barrier
};
// This should be protected, but since CodeGenerator wants to use it, it
// needs to go out here :(
BufferOffset nextOffset() { return m_buffer.nextOffset(); }
protected:
// Shim around AssemblerBufferWithConstantPools::allocEntry.
BufferOffset allocLiteralLoadEntry(size_t numInst, unsigned numPoolEntries,
PoolHintPun& php, uint8_t* data,
const LiteralDoc& doc = LiteralDoc(),
ARMBuffer::PoolEntry* pe = nullptr,
bool loadToPC = false);
Instruction* editSrc(BufferOffset bo) { return m_buffer.getInst(bo); }
#ifdef JS_DISASM_ARM
typedef disasm::EmbeddedVector<char, disasm::ReasonableBufferSize>
DisasmBuffer;
static void disassembleInstruction(const Instruction* i,
DisasmBuffer& buffer);
void initDisassembler();
void finishDisassembler();
void spew(Instruction* i);
void spewBranch(Instruction* i, const LabelDoc& target);
void spewLiteralLoad(PoolHintPun& php, bool loadToPC, const Instruction* offs,
const LiteralDoc& doc);
#endif
public:
void resetCounter();
static uint32_t NopFill;
static uint32_t GetNopFill();
static uint32_t AsmPoolMaxOffset;
static uint32_t GetPoolMaxOffset();
protected:
// Structure for fixing up pc-relative loads/jumps when a the machine code
// gets moved (executable copy, gc, etc.).
class RelativePatch {
void* target_;
RelocationKind kind_;
public:
RelativePatch(void* target, RelocationKind kind)
: target_(target), kind_(kind) {}
void* target() const { return target_; }
RelocationKind kind() const { return kind_; }
};
// TODO: this should actually be a pool-like object. It is currently a big
// hack, and probably shouldn't exist.
js::Vector<RelativePatch, 8, SystemAllocPolicy> jumps_;
CompactBufferWriter jumpRelocations_;
CompactBufferWriter dataRelocations_;
ARMBuffer m_buffer;
#ifdef JS_DISASM_ARM
DisassemblerSpew spew_;
#endif
public:
// For the alignment fill use NOP: 0x0320f000 or (Always | InstNOP::NopInst).
// For the nopFill use a branch to the next instruction: 0xeaffffff.
Assembler()
: m_buffer(1, 1, 8, GetPoolMaxOffset(), 8, 0xe320f000, 0xeaffffff,
GetNopFill()),
isFinished(false),
dtmActive(false),
dtmCond(Always) {
#ifdef JS_DISASM_ARM
initDisassembler();
#endif
}
~Assembler() {
#ifdef JS_DISASM_ARM
finishDisassembler();
#endif
}
void setUnlimitedBuffer() { m_buffer.setUnlimited(); }
static Condition InvertCondition(Condition cond);
static Condition UnsignedCondition(Condition cond);
static Condition ConditionWithoutEqual(Condition cond);
static DoubleCondition InvertCondition(DoubleCondition cond);
void writeDataRelocation(BufferOffset offset, ImmGCPtr ptr) {
// Raw GC pointer relocations and Value relocations both end up in
// Assembler::TraceDataRelocations.
if (ptr.value) {
if (gc::IsInsideNursery(ptr.value)) {
embedsNurseryPointers_ = true;
}
dataRelocations_.writeUnsigned(offset.getOffset());
}
}
enum RelocBranchStyle { B_MOVWT, B_LDR_BX, B_LDR, B_MOVW_ADD };
enum RelocStyle { L_MOVWT, L_LDR };
public:
// Given the start of a Control Flow sequence, grab the value that is
// finally branched to given the start of a function that loads an address
// into a register get the address that ends up in the register.
template <class Iter>
static const uint32_t* GetCF32Target(Iter* iter);
static uintptr_t GetPointer(uint8_t*);
static const uint32_t* GetPtr32Target(InstructionIterator iter,
Register* dest = nullptr,
RelocStyle* rs = nullptr);
bool oom() const;
void setPrinter(Sprinter* sp) {
#ifdef JS_DISASM_ARM
spew_.setPrinter(sp);
#endif
}
Register getStackPointer() const { return StackPointer; }
private:
bool isFinished;
protected:
LabelDoc refLabel(const Label* label) {
#ifdef JS_DISASM_ARM
return spew_.refLabel(label);
#else
return LabelDoc();
#endif
}
public:
void finish();
bool appendRawCode(const uint8_t* code, size_t numBytes);
bool reserve(size_t size);
bool swapBuffer(wasm::Bytes& bytes);
void copyJumpRelocationTable(uint8_t* dest);
void copyDataRelocationTable(uint8_t* dest);
// Size of the instruction stream, in bytes, after pools are flushed.
size_t size() const;
// Size of the jump relocation table, in bytes.
size_t jumpRelocationTableBytes() const;
size_t dataRelocationTableBytes() const;
// Size of the data table, in bytes.
size_t bytesNeeded() const;
// Write a single instruction into the instruction stream. Very hot,
// inlined for performance
MOZ_ALWAYS_INLINE BufferOffset writeInst(uint32_t x) {
MOZ_ASSERT(hasCreator());
BufferOffset offs = m_buffer.putInt(x);
#ifdef JS_DISASM_ARM
spew(m_buffer.getInstOrNull(offs));
#endif
return offs;
}
// As above, but also mark the instruction as a branch. Very hot, inlined
// for performance
MOZ_ALWAYS_INLINE BufferOffset
writeBranchInst(uint32_t x, const LabelDoc& documentation) {
BufferOffset offs = m_buffer.putInt(x);
#ifdef JS_DISASM_ARM
spewBranch(m_buffer.getInstOrNull(offs), documentation);
#endif
return offs;
}
// Write a placeholder NOP for a branch into the instruction stream
// (in order to adjust assembler addresses and mark it as a branch), it will
// be overwritten subsequently.
BufferOffset allocBranchInst();
// A static variant for the cases where we don't want to have an assembler
// object.
static void WriteInstStatic(uint32_t x, uint32_t* dest);
public:
void writeCodePointer(CodeLabel* label);
void haltingAlign(int alignment);
void nopAlign(int alignment);
BufferOffset as_nop();
BufferOffset as_alu(Register dest, Register src1, Operand2 op2, ALUOp op,
SBit s = LeaveCC, Condition c = Always);
BufferOffset as_mov(Register dest, Operand2 op2, SBit s = LeaveCC,
Condition c = Always);
BufferOffset as_mvn(Register dest, Operand2 op2, SBit s = LeaveCC,
Condition c = Always);
static void as_alu_patch(Register dest, Register src1, Operand2 op2, ALUOp op,
SBit s, Condition c, uint32_t* pos);
static void as_mov_patch(Register dest, Operand2 op2, SBit s, Condition c,
uint32_t* pos);
// Logical operations:
BufferOffset as_and(Register dest, Register src1, Operand2 op2,
SBit s = LeaveCC, Condition c = Always);
BufferOffset as_bic(Register dest, Register src1, Operand2 op2,
SBit s = LeaveCC, Condition c = Always);
BufferOffset as_eor(Register dest, Register src1, Operand2 op2,
SBit s = LeaveCC, Condition c = Always);
BufferOffset as_orr(Register dest, Register src1, Operand2 op2,
SBit s = LeaveCC, Condition c = Always);
// Reverse byte operations:
BufferOffset as_rev(Register dest, Register src, Condition c = Always);
BufferOffset as_rev16(Register dest, Register src, Condition c = Always);
BufferOffset as_revsh(Register dest, Register src, Condition c = Always);
// Mathematical operations:
BufferOffset as_adc(Register dest, Register src1, Operand2 op2,
SBit s = LeaveCC, Condition c = Always);
BufferOffset as_add(Register dest, Register src1, Operand2 op2,
SBit s = LeaveCC, Condition c = Always);
BufferOffset as_sbc(Register dest, Register src1, Operand2 op2,
SBit s = LeaveCC, Condition c = Always);
BufferOffset as_sub(Register dest, Register src1, Operand2 op2,
SBit s = LeaveCC, Condition c = Always);
BufferOffset as_rsb(Register dest, Register src1, Operand2 op2,
SBit s = LeaveCC, Condition c = Always);
BufferOffset as_rsc(Register dest, Register src1, Operand2 op2,
SBit s = LeaveCC, Condition c = Always);
// Test operations:
BufferOffset as_cmn(Register src1, Operand2 op2, Condition c = Always);
BufferOffset as_cmp(Register src1, Operand2 op2, Condition c = Always);
BufferOffset as_teq(Register src1, Operand2 op2, Condition c = Always);
BufferOffset as_tst(Register src1, Operand2 op2, Condition c = Always);
// Sign extension operations:
BufferOffset as_sxtb(Register dest, Register src, int rotate,
Condition c = Always);
BufferOffset as_sxth(Register dest, Register src, int rotate,
Condition c = Always);
BufferOffset as_uxtb(Register dest, Register src, int rotate,
Condition c = Always);
BufferOffset as_uxth(Register dest, Register src, int rotate,
Condition c = Always);
// Not quite ALU worthy, but useful none the less: These also have the issue
// of these being formatted completly differently from the standard ALU
// operations.
BufferOffset as_movw(Register dest, Imm16 imm, Condition c = Always);
BufferOffset as_movt(Register dest, Imm16 imm, Condition c = Always);
static void as_movw_patch(Register dest, Imm16 imm, Condition c,
Instruction* pos);
static void as_movt_patch(Register dest, Imm16 imm, Condition c,
Instruction* pos);
BufferOffset as_genmul(Register d1, Register d2, Register rm, Register rn,
MULOp op, SBit s, Condition c = Always);
BufferOffset as_mul(Register dest, Register src1, Register src2,
SBit s = LeaveCC, Condition c = Always);
BufferOffset as_mla(Register dest, Register acc, Register src1, Register src2,
SBit s = LeaveCC, Condition c = Always);
BufferOffset as_umaal(Register dest1, Register dest2, Register src1,
Register src2, Condition c = Always);
BufferOffset as_mls(Register dest, Register acc, Register src1, Register src2,
Condition c = Always);
BufferOffset as_umull(Register dest1, Register dest2, Register src1,
Register src2, SBit s = LeaveCC, Condition c = Always);
BufferOffset as_umlal(Register dest1, Register dest2, Register src1,
Register src2, SBit s = LeaveCC, Condition c = Always);
BufferOffset as_smull(Register dest1, Register dest2, Register src1,
Register src2, SBit s = LeaveCC, Condition c = Always);
BufferOffset as_smlal(Register dest1, Register dest2, Register src1,
Register src2, SBit s = LeaveCC, Condition c = Always);
BufferOffset as_sdiv(Register dest, Register num, Register div,
Condition c = Always);
BufferOffset as_udiv(Register dest, Register num, Register div,
Condition c = Always);
BufferOffset as_clz(Register dest, Register src, Condition c = Always);
// Data transfer instructions: ldr, str, ldrb, strb.
// Using an int to differentiate between 8 bits and 32 bits is overkill.
BufferOffset as_dtr(LoadStore ls, int size, Index mode, Register rt,
DTRAddr addr, Condition c = Always);
static void as_dtr_patch(LoadStore ls, int size, Index mode, Register rt,
DTRAddr addr, Condition c, uint32_t* dest);
// Handles all of the other integral data transferring functions:
// ldrsb, ldrsh, ldrd, etc. The size is given in bits.
BufferOffset as_extdtr(LoadStore ls, int size, bool IsSigned, Index mode,
Register rt, EDtrAddr addr, Condition c = Always);
BufferOffset as_dtm(LoadStore ls, Register rn, uint32_t mask, DTMMode mode,
DTMWriteBack wb, Condition c = Always);
// Overwrite a pool entry with new data.
static void WritePoolEntry(Instruction* addr, Condition c, uint32_t data);
// Load a 32 bit immediate from a pool into a register.
BufferOffset as_Imm32Pool(Register dest, uint32_t value,
Condition c = Always);
// Load a 64 bit floating point immediate from a pool into a register.
BufferOffset as_FImm64Pool(VFPRegister dest, double value,
Condition c = Always);
// Load a 32 bit floating point immediate from a pool into a register.
BufferOffset as_FImm32Pool(VFPRegister dest, float value,
Condition c = Always);
// Atomic instructions: ldrexd, ldrex, ldrexh, ldrexb, strexd, strex, strexh,
// strexb.
//
// The doubleword, halfword, and byte versions are available from ARMv6K
// forward.
//
// The word versions are available from ARMv6 forward and can be used to
// implement the halfword and byte versions on older systems.
// LDREXD rt, rt2, [rn]. Constraint: rt even register, rt2=rt+1.
BufferOffset as_ldrexd(Register rt, Register rt2, Register rn,
Condition c = Always);
// LDREX rt, [rn]
BufferOffset as_ldrex(Register rt, Register rn, Condition c = Always);
BufferOffset as_ldrexh(Register rt, Register rn, Condition c = Always);
BufferOffset as_ldrexb(Register rt, Register rn, Condition c = Always);
// STREXD rd, rt, rt2, [rn]. Constraint: rt even register, rt2=rt+1.
BufferOffset as_strexd(Register rd, Register rt, Register rt2, Register rn,
Condition c = Always);
// STREX rd, rt, [rn]. Constraint: rd != rn, rd != rt.
BufferOffset as_strex(Register rd, Register rt, Register rn,
Condition c = Always);
BufferOffset as_strexh(Register rd, Register rt, Register rn,
Condition c = Always);
BufferOffset as_strexb(Register rd, Register rt, Register rn,
Condition c = Always);
// CLREX
BufferOffset as_clrex();
// Memory synchronization.
// These are available from ARMv7 forward.
BufferOffset as_dmb(BarrierOption option = BarrierSY);
BufferOffset as_dsb(BarrierOption option = BarrierSY);
BufferOffset as_isb();
// Memory synchronization for architectures before ARMv7.
BufferOffset as_dsb_trap();
BufferOffset as_dmb_trap();
BufferOffset as_isb_trap();
// Speculation barrier
BufferOffset as_csdb();
// Control flow stuff:
// bx can *only* branch to a register never to an immediate.
BufferOffset as_bx(Register r, Condition c = Always);
// Branch can branch to an immediate *or* to a register. Branches to
// immediates are pc relative, branches to registers are absolute.
BufferOffset as_b(BOffImm off, Condition c, Label* documentation = nullptr);
BufferOffset as_b(Label* l, Condition c = Always);
BufferOffset as_b(BOffImm off, Condition c, BufferOffset inst);
// blx can go to either an immediate or a register. When blx'ing to a
// register, we change processor mode depending on the low bit of the
// register when blx'ing to an immediate, we *always* change processor
// state.
BufferOffset as_blx(Label* l);
BufferOffset as_blx(Register r, Condition c = Always);
BufferOffset as_bl(BOffImm off, Condition c, Label* documentation = nullptr);
// bl can only branch+link to an immediate, never to a register it never
// changes processor state.
BufferOffset as_bl();
// bl #imm can have a condition code, blx #imm cannot.
// blx reg can be conditional.
BufferOffset as_bl(Label* l, Condition c);
BufferOffset as_bl(BOffImm off, Condition c, BufferOffset inst);
BufferOffset as_mrs(Register r, Condition c = Always);
BufferOffset as_msr(Register r, Condition c = Always);
// VFP instructions!
private:
enum vfp_size { IsDouble = 1 << 8, IsSingle = 0 << 8 };
BufferOffset writeVFPInst(vfp_size sz, uint32_t blob);
static void WriteVFPInstStatic(vfp_size sz, uint32_t blob, uint32_t* dest);
// Unityped variants: all registers hold the same (ieee754 single/double)
// notably not included are vcvt; vmov vd, #imm; vmov rt, vn.
BufferOffset as_vfp_float(VFPRegister vd, VFPRegister vn, VFPRegister vm,
VFPOp op, Condition c = Always);
public:
BufferOffset as_vadd(VFPRegister vd, VFPRegister vn, VFPRegister vm,
Condition c = Always);
BufferOffset as_vdiv(VFPRegister vd, VFPRegister vn, VFPRegister vm,
Condition c = Always);
BufferOffset as_vmul(VFPRegister vd, VFPRegister vn, VFPRegister vm,
Condition c = Always);
BufferOffset as_vnmul(VFPRegister vd, VFPRegister vn, VFPRegister vm,
Condition c = Always);
BufferOffset as_vnmla(VFPRegister vd, VFPRegister vn, VFPRegister vm,
Condition c = Always);
BufferOffset as_vnmls(VFPRegister vd, VFPRegister vn, VFPRegister vm,
Condition c = Always);
BufferOffset as_vneg(VFPRegister vd, VFPRegister vm, Condition c = Always);
BufferOffset as_vsqrt(VFPRegister vd, VFPRegister vm, Condition c = Always);
BufferOffset as_vabs(VFPRegister vd, VFPRegister vm, Condition c = Always);
BufferOffset as_vsub(VFPRegister vd, VFPRegister vn, VFPRegister vm,
Condition c = Always);
BufferOffset as_vcmp(VFPRegister vd, VFPRegister vm, Condition c = Always);
BufferOffset as_vcmpz(VFPRegister vd, Condition c = Always);
// Specifically, a move between two same sized-registers.
BufferOffset as_vmov(VFPRegister vd, VFPRegister vsrc, Condition c = Always);
// Transfer between Core and VFP.
enum FloatToCore_ { FloatToCore = 1 << 20, CoreToFloat = 0 << 20 };
private:
enum VFPXferSize { WordTransfer = 0x02000010, DoubleTransfer = 0x00400010 };
public:
// Unlike the next function, moving between the core registers and vfp
// registers can't be *that* properly typed. Namely, since I don't want to
// munge the type VFPRegister to also include core registers. Thus, the core
// and vfp registers are passed in based on their type, and src/dest is
// determined by the float2core.
BufferOffset as_vxfer(Register vt1, Register vt2, VFPRegister vm,
FloatToCore_ f2c, Condition c = Always, int idx = 0);
// Our encoding actually allows just the src and the dest (and their types)
// to uniquely specify the encoding that we are going to use.
BufferOffset as_vcvt(VFPRegister vd, VFPRegister vm, bool useFPSCR = false,
Condition c = Always);
// Hard coded to a 32 bit fixed width result for now.
BufferOffset as_vcvtFixed(VFPRegister vd, bool isSigned, uint32_t fixedPoint,
bool toFixed, Condition c = Always);
// Transfer between VFP and memory.
BufferOffset as_vdtr(LoadStore ls, VFPRegister vd, VFPAddr addr,
Condition c = Always /* vfp doesn't have a wb option*/);
static void as_vdtr_patch(LoadStore ls, VFPRegister vd, VFPAddr addr,
Condition c /* vfp doesn't have a wb option */,
uint32_t* dest);
// VFP's ldm/stm work differently from the standard arm ones. You can only
// transfer a range.
BufferOffset as_vdtm(LoadStore st, Register rn, VFPRegister vd, int length,
/* also has update conditions */ Condition c = Always);
// vldr/vstr variants that handle unaligned accesses. These encode as NEON
// single-element instructions and can only be used if NEON is available.
// Here, vd must be tagged as a float or double register.
BufferOffset as_vldr_unaligned(VFPRegister vd, Register rn);
BufferOffset as_vstr_unaligned(VFPRegister vd, Register rn);
BufferOffset as_vimm(VFPRegister vd, VFPImm imm, Condition c = Always);
BufferOffset as_vmrs(Register r, Condition c = Always);
BufferOffset as_vmsr(Register r, Condition c = Always);
// Label operations.
bool nextLink(BufferOffset b, BufferOffset* next);
void bind(Label* label, BufferOffset boff = BufferOffset());
uint32_t currentOffset() { return nextOffset().getOffset(); }
void retarget(Label* label, Label* target);
// I'm going to pretend this doesn't exist for now.
void retarget(Label* label, void* target, RelocationKind reloc);
static void Bind(uint8_t* rawCode, const CodeLabel& label);
void as_bkpt();
BufferOffset as_illegal_trap();
public:
static void TraceJumpRelocations(JSTracer* trc, JitCode* code,
CompactBufferReader& reader);
static void TraceDataRelocations(JSTracer* trc, JitCode* code,
CompactBufferReader& reader);
void assertNoGCThings() const {
#ifdef DEBUG
MOZ_ASSERT(dataRelocations_.length() == 0);
for (auto& j : jumps_) {
MOZ_ASSERT(j.kind() == RelocationKind::HARDCODED);
}
#endif
}
static bool SupportsFloatingPoint() { return HasVFP(); }
static bool SupportsUnalignedAccesses() { return HasARMv7(); }
// Note, returning false here is technically wrong, but one has to go via the
// as_vldr_unaligned and as_vstr_unaligned instructions to get proper behavior
// and those are NEON-specific and have to be asked for specifically.
static bool SupportsFastUnalignedFPAccesses() { return false; }
static bool HasRoundInstruction(RoundingMode mode) { return false; }
protected:
void addPendingJump(BufferOffset src, ImmPtr target, RelocationKind kind) {
enoughMemory_ &= jumps_.append(RelativePatch(target.value, kind));
if (kind == RelocationKind::JITCODE) {
jumpRelocations_.writeUnsigned(src.getOffset());
}
}
public:
// The buffer is about to be linked, make sure any constant pools or excess
// bookkeeping has been flushed to the instruction stream.
void flush() {
MOZ_ASSERT(!isFinished);
m_buffer.flushPool();
return;
}
void comment(const char* msg) {
#ifdef JS_DISASM_ARM
spew_.spew("; %s", msg);
#endif
}
// Copy the assembly code to the given buffer, and perform any pending
// relocations relying on the target address.
void executableCopy(uint8_t* buffer);
// Actual assembly emitting functions.
// Since I can't think of a reasonable default for the mode, I'm going to
// leave it as a required argument.
void startDataTransferM(LoadStore ls, Register rm, DTMMode mode,
DTMWriteBack update = NoWriteBack,
Condition c = Always) {
MOZ_ASSERT(!dtmActive);
dtmUpdate = update;
dtmBase = rm;
dtmLoadStore = ls;
dtmLastReg = -1;
dtmRegBitField = 0;
dtmActive = 1;
dtmCond = c;
dtmMode = mode;
}
void transferReg(Register rn) {
MOZ_ASSERT(dtmActive);
MOZ_ASSERT(rn.code() > dtmLastReg);
dtmRegBitField |= 1 << rn.code();
if (dtmLoadStore == IsLoad && rn.code() == 13 && dtmBase.code() == 13) {
MOZ_CRASH("ARM Spec says this is invalid");
}
}
void finishDataTransfer() {
dtmActive = false;
as_dtm(dtmLoadStore, dtmBase, dtmRegBitField, dtmMode, dtmUpdate, dtmCond);
}
void startFloatTransferM(LoadStore ls, Register rm, DTMMode mode,
DTMWriteBack update = NoWriteBack,
Condition c = Always) {
MOZ_ASSERT(!dtmActive);
dtmActive = true;
dtmUpdate = update;
dtmLoadStore = ls;
dtmBase = rm;
dtmCond = c;
dtmLastReg = -1;
dtmMode = mode;
dtmDelta = 0;
}
void transferFloatReg(VFPRegister rn) {
if (dtmLastReg == -1) {
vdtmFirstReg = rn.code();
} else {
if (dtmDelta == 0) {
dtmDelta = rn.code() - dtmLastReg;
MOZ_ASSERT(dtmDelta == 1 || dtmDelta == -1);
}
MOZ_ASSERT(dtmLastReg >= 0);
MOZ_ASSERT(rn.code() == unsigned(dtmLastReg) + dtmDelta);
}
dtmLastReg = rn.code();
}
void finishFloatTransfer() {
MOZ_ASSERT(dtmActive);
dtmActive = false;
MOZ_ASSERT(dtmLastReg != -1);
dtmDelta = dtmDelta ? dtmDelta : 1;
// The operand for the vstr/vldr instruction is the lowest register in the
// range.
int low = std::min(dtmLastReg, vdtmFirstReg);
int high = std::max(dtmLastReg, vdtmFirstReg);
// Fencepost problem.
int len = high - low + 1;
// vdtm can only transfer 16 registers at once. If we need to transfer
// more, then either hoops are necessary, or we need to be updating the
// register.
MOZ_ASSERT_IF(len > 16, dtmUpdate == WriteBack);
int adjustLow = dtmLoadStore == IsStore ? 0 : 1;
int adjustHigh = dtmLoadStore == IsStore ? -1 : 0;
while (len > 0) {
// Limit the instruction to 16 registers.
int curLen = std::min(len, 16);
// If it is a store, we want to start at the high end and move down
// (e.g. vpush d16-d31; vpush d0-d15).
int curStart = (dtmLoadStore == IsStore) ? high - curLen + 1 : low;
as_vdtm(dtmLoadStore, dtmBase,
VFPRegister(FloatRegister::FromCode(curStart)), curLen, dtmCond);
// Update the bounds.
low += adjustLow * curLen;
high += adjustHigh * curLen;
// Update the length parameter.
len -= curLen;
}
}
private:
int dtmRegBitField;
int vdtmFirstReg;
int dtmLastReg;
int dtmDelta;
Register dtmBase;
DTMWriteBack dtmUpdate;
DTMMode dtmMode;
LoadStore dtmLoadStore;
bool dtmActive;
Condition dtmCond;
public:
enum {
PadForAlign8 = (int)0x00,
PadForAlign16 = (int)0x0000,
PadForAlign32 = (int)0xe12fff7f // 'bkpt 0xffff'
};
// API for speaking with the IonAssemblerBufferWithConstantPools generate an
// initial placeholder instruction that we want to later fix up.
static void InsertIndexIntoTag(uint8_t* load, uint32_t index);
// Take the stub value that was written in before, and write in an actual
// load using the index we'd computed previously as well as the address of
// the pool start.
static void PatchConstantPoolLoad(void* loadAddr, void* constPoolAddr);
// We're not tracking short-range branches for ARM for now.
static void PatchShortRangeBranchToVeneer(ARMBuffer*, unsigned rangeIdx,
BufferOffset deadline,
BufferOffset veneer) {
MOZ_CRASH();
}
// END API
// Move our entire pool into the instruction stream. This is to force an
// opportunistic dump of the pool, prefferably when it is more convenient to
// do a dump.
void flushBuffer();
void enterNoPool(size_t maxInst);
void leaveNoPool();
void enterNoNops();
void leaveNoNops();
static void WritePoolHeader(uint8_t* start, Pool* p, bool isNatural);
static void WritePoolGuard(BufferOffset branch, Instruction* inst,
BufferOffset dest);
static uint32_t PatchWrite_NearCallSize();
static uint32_t NopSize() { return 4; }
static void PatchWrite_NearCall(CodeLocationLabel start,
CodeLocationLabel toCall);
static void PatchDataWithValueCheck(CodeLocationLabel label,
PatchedImmPtr newValue,
PatchedImmPtr expectedValue);
static void PatchDataWithValueCheck(CodeLocationLabel label, ImmPtr newValue,
ImmPtr expectedValue);
static void PatchWrite_Imm32(CodeLocationLabel label, Imm32 imm);
static uint32_t AlignDoubleArg(uint32_t offset) { return (offset + 1) & ~1; }
static uint8_t* NextInstruction(uint8_t* instruction,
uint32_t* count = nullptr);
// Toggle a jmp or cmp emitted by toggledJump().
static void ToggleToJmp(CodeLocationLabel inst_);
static void ToggleToCmp(CodeLocationLabel inst_);
static size_t ToggledCallSize(uint8_t* code);
static void ToggleCall(CodeLocationLabel inst_, bool enabled);
void processCodeLabels(uint8_t* rawCode);
void verifyHeapAccessDisassembly(uint32_t begin, uint32_t end,
const Disassembler::HeapAccess& heapAccess) {
// Implement this if we implement a disassembler.
}
}; // Assembler
// An Instruction is a structure for both encoding and decoding any and all ARM
// instructions. Many classes have not been implemented thus far.
class Instruction {
uint32_t data;
protected:
// This is not for defaulting to always, this is for instructions that
// cannot be made conditional, and have the usually invalid 4b1111 cond
// field.
explicit Instruction(uint32_t data_, bool fake = false)
: data(data_ | 0xf0000000) {
MOZ_ASSERT(fake || ((data_ & 0xf0000000) == 0));
}
// Standard constructor.
Instruction(uint32_t data_, Assembler::Condition c)
: data(data_ | (uint32_t)c) {
MOZ_ASSERT((data_ & 0xf0000000) == 0);
}
// You should never create an instruction directly. You should create a more
// specific instruction which will eventually call one of these constructors
// for you.
public:
uint32_t encode() const { return data; }
// Check if this instruction is really a particular case.
template <class C>
bool is() const {
return C::IsTHIS(*this);
}
// Safely get a more specific variant of this pointer.
template <class C>
C* as() const {
return C::AsTHIS(*this);
}
const Instruction& operator=(Instruction src) {
data = src.data;
return *this;
}
// Since almost all instructions have condition codes, the condition code
// extractor resides in the base class.
Assembler::Condition extractCond() const {
MOZ_ASSERT(data >> 28 != 0xf,
"The instruction does not have condition code");
return (Assembler::Condition)(data & 0xf0000000);
}
// Sometimes, an api wants a uint32_t (or a pointer to it) rather than an
// instruction. raw() just coerces this into a pointer to a uint32_t.
const uint32_t* raw() const { return &data; }
uint32_t size() const { return 4; }
}; // Instruction
// Make sure that it is the right size.
static_assert(sizeof(Instruction) == 4);
inline void InstructionIterator::advanceRaw(ptrdiff_t instructions) {
inst_ = inst_ + instructions;
}
// Data Transfer Instructions.
class InstDTR : public Instruction {
public:
enum IsByte_ { IsByte = 0x00400000, IsWord = 0x00000000 };
static const int IsDTR = 0x04000000;
static const int IsDTRMask = 0x0c000000;
// TODO: Replace the initialization with something that is safer.
InstDTR(LoadStore ls, IsByte_ ib, Index mode, Register rt, DTRAddr addr,
Assembler::Condition c)
: Instruction(std::underlying_type_t<LoadStore>(ls) |
std::underlying_type_t<IsByte_>(ib) |
std::underlying_type_t<Index>(mode) | RT(rt) |
addr.encode() | IsDTR,
c) {}
static bool IsTHIS(const Instruction& i);
static InstDTR* AsTHIS(const Instruction& i);
};
static_assert(sizeof(InstDTR) == sizeof(Instruction));
class InstLDR : public InstDTR {
public:
InstLDR(Index mode, Register rt, DTRAddr addr, Assembler::Condition c)
: InstDTR(IsLoad, IsWord, mode, rt, addr, c) {}
static bool IsTHIS(const Instruction& i);
static InstLDR* AsTHIS(const Instruction& i);
int32_t signedOffset() const {
int32_t offset = encode() & 0xfff;
if (IsUp_(encode() & IsUp) != IsUp) {
return -offset;
}
return offset;
}
uint32_t* dest() const {
int32_t offset = signedOffset();
// When patching the load in PatchConstantPoolLoad, we ensure that the
// offset is a multiple of 4, offset by 8 bytes from the actual
// location. Indeed, when the base register is PC, ARM's 3 stages
// pipeline design makes it that PC is off by 8 bytes (= 2 *
// sizeof(uint32*)) when we actually executed it.
MOZ_ASSERT(offset % 4 == 0);
offset >>= 2;
return (uint32_t*)raw() + offset + 2;
}
};
static_assert(sizeof(InstDTR) == sizeof(InstLDR));
class InstNOP : public Instruction {
public:
static const uint32_t NopInst = 0x0320f000;
InstNOP() : Instruction(NopInst, Assembler::Always) {}
static bool IsTHIS(const Instruction& i);
static InstNOP* AsTHIS(Instruction& i);
};
// Branching to a register, or calling a register
class InstBranchReg : public Instruction {
protected:
// Don't use BranchTag yourself, use a derived instruction.
enum BranchTag { IsBX = 0x012fff10, IsBLX = 0x012fff30 };
static const uint32_t IsBRegMask = 0x0ffffff0;
InstBranchReg(BranchTag tag, Register rm, Assembler::Condition c)
: Instruction(tag | rm.code(), c) {}
public:
static bool IsTHIS(const Instruction& i);
static InstBranchReg* AsTHIS(const Instruction& i);
// Get the register that is being branched to
void extractDest(Register* dest);
// Make sure we are branching to a pre-known register
bool checkDest(Register dest);
};
static_assert(sizeof(InstBranchReg) == sizeof(Instruction));
// Branching to an immediate offset, or calling an immediate offset
class InstBranchImm : public Instruction {
protected:
enum BranchTag { IsB = 0x0a000000, IsBL = 0x0b000000 };
static const uint32_t IsBImmMask = 0x0f000000;
InstBranchImm(BranchTag tag, BOffImm off, Assembler::Condition c)
: Instruction(tag | off.encode(), c) {}
public:
static bool IsTHIS(const Instruction& i);
static InstBranchImm* AsTHIS(const Instruction& i);
void extractImm(BOffImm* dest);
};
static_assert(sizeof(InstBranchImm) == sizeof(Instruction));
// Very specific branching instructions.
class InstBXReg : public InstBranchReg {
public:
static bool IsTHIS(const Instruction& i);
static InstBXReg* AsTHIS(const Instruction& i);
};
class InstBLXReg : public InstBranchReg {
public:
InstBLXReg(Register reg, Assembler::Condition c)
: InstBranchReg(IsBLX, reg, c) {}
static bool IsTHIS(const Instruction& i);
static InstBLXReg* AsTHIS(const Instruction& i);
};
class InstBImm : public InstBranchImm {
public:
InstBImm(BOffImm off, Assembler::Condition c) : InstBranchImm(IsB, off, c) {}
static bool IsTHIS(const Instruction& i);
static InstBImm* AsTHIS(const Instruction& i);
};
class InstBLImm : public InstBranchImm {
public:
InstBLImm(BOffImm off, Assembler::Condition c)
: InstBranchImm(IsBL, off, c) {}
static bool IsTHIS(const Instruction& i);
static InstBLImm* AsTHIS(const Instruction& i);
};
// Both movw and movt. The layout of both the immediate and the destination
// register is the same so the code is being shared.
class InstMovWT : public Instruction {
protected:
enum WT { IsW = 0x03000000, IsT = 0x03400000 };
static const uint32_t IsWTMask = 0x0ff00000;
InstMovWT(Register rd, Imm16 imm, WT wt, Assembler::Condition c)
: Instruction(RD(rd) | imm.encode() | wt, c) {}
public:
void extractImm(Imm16* dest);
void extractDest(Register* dest);
bool checkImm(Imm16 dest);
bool checkDest(Register dest);
static bool IsTHIS(Instruction& i);
static InstMovWT* AsTHIS(Instruction& i);
};
static_assert(sizeof(InstMovWT) == sizeof(Instruction));
class InstMovW : public InstMovWT {
public:
InstMovW(Register rd, Imm16 imm, Assembler::Condition c)
: InstMovWT(rd, imm, IsW, c) {}
static bool IsTHIS(const Instruction& i);
static InstMovW* AsTHIS(const Instruction& i);
};
class InstMovT : public InstMovWT {
public:
InstMovT(Register rd, Imm16 imm, Assembler::Condition c)
: InstMovWT(rd, imm, IsT, c) {}
static bool IsTHIS(const Instruction& i);
static InstMovT* AsTHIS(const Instruction& i);
};
class InstALU : public Instruction {
static const int32_t ALUMask = 0xc << 24;
public:
InstALU(Register rd, Register rn, Operand2 op2, ALUOp op, SBit s,
Assembler::Condition c)
: Instruction(maybeRD(rd) | maybeRN(rn) | op2.encode() | op | s, c) {}
static bool IsTHIS(const Instruction& i);
static InstALU* AsTHIS(const Instruction& i);
void extractOp(ALUOp* ret);
bool checkOp(ALUOp op);
void extractDest(Register* ret);
bool checkDest(Register rd);
void extractOp1(Register* ret);
bool checkOp1(Register rn);
Operand2 extractOp2();
};
class InstCMP : public InstALU {
public:
static bool IsTHIS(const Instruction& i);
static InstCMP* AsTHIS(const Instruction& i);
};
class InstMOV : public InstALU {
public:
static bool IsTHIS(const Instruction& i);
static InstMOV* AsTHIS(const Instruction& i);
};
// Compile-time iterator over instructions, with a safe interface that
// references not-necessarily-linear Instructions by linear BufferOffset.
class BufferInstructionIterator
: public ARMBuffer::AssemblerBufferInstIterator {
public:
BufferInstructionIterator(BufferOffset bo, ARMBuffer* buffer)
: ARMBuffer::AssemblerBufferInstIterator(bo, buffer) {}
// Advances the buffer to the next intentionally-inserted instruction.
Instruction* next() {
advance(cur()->size());
maybeSkipAutomaticInstructions();
return cur();
}
// Advances the BufferOffset past any automatically-inserted instructions.
Instruction* maybeSkipAutomaticInstructions();
};
static const uint32_t NumIntArgRegs = 4;
// There are 16 *float* registers available for arguments
// If doubles are used, only half the number of registers are available.
static const uint32_t NumFloatArgRegs = 16;
static inline bool GetIntArgReg(uint32_t usedIntArgs, uint32_t usedFloatArgs,
Register* out) {
if (usedIntArgs >= NumIntArgRegs) {
return false;
}
*out = Register::FromCode(usedIntArgs);
return true;
}
// Get a register in which we plan to put a quantity that will be used as an
// integer argument. This differs from GetIntArgReg in that if we have no more
// actual argument registers to use we will fall back on using whatever
// CallTempReg* don't overlap the argument registers, and only fail once those
// run out too.
static inline bool GetTempRegForIntArg(uint32_t usedIntArgs,
uint32_t usedFloatArgs, Register* out) {
if (GetIntArgReg(usedIntArgs, usedFloatArgs, out)) {
return true;
}
// Unfortunately, we have to assume things about the point at which
// GetIntArgReg returns false, because we need to know how many registers it
// can allocate.
usedIntArgs -= NumIntArgRegs;
if (usedIntArgs >= NumCallTempNonArgRegs) {
return false;
}
*out = CallTempNonArgRegs[usedIntArgs];
return true;
}
#if defined(JS_CODEGEN_ARM_HARDFP) || defined(JS_SIMULATOR_ARM)
static inline bool GetFloat32ArgReg(uint32_t usedIntArgs,
uint32_t usedFloatArgs,
FloatRegister* out) {
MOZ_ASSERT(UseHardFpABI());
if (usedFloatArgs >= NumFloatArgRegs) {
return false;
}
*out = VFPRegister(usedFloatArgs, VFPRegister::Single);
return true;
}
static inline bool GetDoubleArgReg(uint32_t usedIntArgs, uint32_t usedFloatArgs,
FloatRegister* out) {
MOZ_ASSERT(UseHardFpABI());
MOZ_ASSERT((usedFloatArgs % 2) == 0);
if (usedFloatArgs >= NumFloatArgRegs) {
return false;
}
*out = VFPRegister(usedFloatArgs >> 1, VFPRegister::Double);
return true;
}
#endif
class DoubleEncoder {
struct DoubleEntry {
uint32_t dblTop;
datastore::Imm8VFPImmData data;
};
static const DoubleEntry table[256];
public:
bool lookup(uint32_t top, datastore::Imm8VFPImmData* ret) const {
for (int i = 0; i < 256; i++) {
if (table[i].dblTop == top) {
*ret = table[i].data;
return true;
}
}
return false;
}
};
// Forbids nop filling for testing purposes. Not nestable.
class AutoForbidNops {
protected:
Assembler* masm_;
public:
explicit AutoForbidNops(Assembler* masm) : masm_(masm) {
masm_->enterNoNops();
}
~AutoForbidNops() { masm_->leaveNoNops(); }
};
class AutoForbidPoolsAndNops : public AutoForbidNops {
public:
// The maxInst argument is the maximum number of word sized instructions
// that will be allocated within this context. It is used to determine if
// the pool needs to be dumped before entering this content. The debug code
// checks that no more than maxInst instructions are actually allocated.
//
// Allocation of pool entries is not supported within this content so the
// code can not use large integers or float constants etc.
AutoForbidPoolsAndNops(Assembler* masm, size_t maxInst)
: AutoForbidNops(masm) {
masm_->enterNoPool(maxInst);
}
~AutoForbidPoolsAndNops() { masm_->leaveNoPool(); }
};
} // namespace jit
} // namespace js
#endif /* jit_arm_Assembler_arm_h */