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llvm-mirror/lib/Target/X86/X86CodeEmitter.cpp
Evan Cheng 50a0af3b57 Clean up. 
llvm-svn: 35105
2007-03-14 20:20:19 +00:00

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//===-- X86/X86CodeEmitter.cpp - Convert X86 code to machine code ---------===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains the pass that transforms the X86 machine instructions into
// relocatable machine code.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "x86-emitter"
#include "X86InstrInfo.h"
#include "X86Subtarget.h"
#include "X86TargetMachine.h"
#include "X86Relocations.h"
#include "X86.h"
#include "llvm/PassManager.h"
#include "llvm/CodeGen/MachineCodeEmitter.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/Function.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Target/TargetOptions.h"
using namespace llvm;
STATISTIC(NumEmitted, "Number of machine instructions emitted");
namespace {
class VISIBILITY_HIDDEN Emitter : public MachineFunctionPass {
const X86InstrInfo *II;
const TargetData *TD;
TargetMachine &TM;
MachineCodeEmitter &MCE;
bool Is64BitMode;
public:
explicit Emitter(TargetMachine &tm, MachineCodeEmitter &mce)
: II(0), TD(0), TM(tm), MCE(mce), Is64BitMode(false) {}
Emitter(TargetMachine &tm, MachineCodeEmitter &mce,
const X86InstrInfo &ii, const TargetData &td, bool is64)
: II(&ii), TD(&td), TM(tm), MCE(mce), Is64BitMode(is64) {}
bool runOnMachineFunction(MachineFunction &MF);
virtual const char *getPassName() const {
return "X86 Machine Code Emitter";
}
void emitInstruction(const MachineInstr &MI);
private:
void emitPCRelativeBlockAddress(MachineBasicBlock *MBB);
void emitPCRelativeValue(intptr_t Address);
void emitGlobalAddressForCall(GlobalValue *GV, bool DoesntNeedStub);
void emitGlobalAddressForPtr(GlobalValue *GV, unsigned Reloc,
int Disp = 0, unsigned PCAdj = 0);
void emitExternalSymbolAddress(const char *ES, unsigned Reloc);
void emitConstPoolAddress(unsigned CPI, unsigned Reloc, int Disp = 0,
unsigned PCAdj = 0);
void emitJumpTableAddress(unsigned JTI, unsigned Reloc, unsigned PCAdj = 0);
void emitDisplacementField(const MachineOperand *RelocOp, int DispVal,
unsigned PCAdj = 0);
void emitRegModRMByte(unsigned ModRMReg, unsigned RegOpcodeField);
void emitSIBByte(unsigned SS, unsigned Index, unsigned Base);
void emitConstant(uint64_t Val, unsigned Size);
void emitMemModRMByte(const MachineInstr &MI,
unsigned Op, unsigned RegOpcodeField,
unsigned PCAdj = 0);
unsigned getX86RegNum(unsigned RegNo);
bool isX86_64ExtendedReg(const MachineOperand &MO);
unsigned determineREX(const MachineInstr &MI);
};
}
/// createX86CodeEmitterPass - Return a pass that emits the collected X86 code
/// to the specified MCE object.
FunctionPass *llvm::createX86CodeEmitterPass(X86TargetMachine &TM,
MachineCodeEmitter &MCE) {
return new Emitter(TM, MCE);
}
bool Emitter::runOnMachineFunction(MachineFunction &MF) {
assert((MF.getTarget().getRelocationModel() != Reloc::Default ||
MF.getTarget().getRelocationModel() != Reloc::Static) &&
"JIT relocation model must be set to static or default!");
II = ((X86TargetMachine&)MF.getTarget()).getInstrInfo();
TD = ((X86TargetMachine&)MF.getTarget()).getTargetData();
Is64BitMode =
((X86TargetMachine&)MF.getTarget()).getSubtarget<X86Subtarget>().is64Bit();
do {
MCE.startFunction(MF);
for (MachineFunction::iterator MBB = MF.begin(), E = MF.end();
MBB != E; ++MBB) {
MCE.StartMachineBasicBlock(MBB);
for (MachineBasicBlock::const_iterator I = MBB->begin(), E = MBB->end();
I != E; ++I)
emitInstruction(*I);
}
} while (MCE.finishFunction(MF));
return false;
}
/// emitPCRelativeValue - Emit a PC relative address.
///
void Emitter::emitPCRelativeValue(intptr_t Address) {
MCE.emitWordLE(Address-MCE.getCurrentPCValue()-4);
}
/// emitPCRelativeBlockAddress - This method keeps track of the information
/// necessary to resolve the address of this block later and emits a dummy
/// value.
///
void Emitter::emitPCRelativeBlockAddress(MachineBasicBlock *MBB) {
// Remember where this reference was and where it is to so we can
// deal with it later.
MCE.addRelocation(MachineRelocation::getBB(MCE.getCurrentPCOffset(),
X86::reloc_pcrel_word, MBB));
MCE.emitWordLE(0);
}
/// emitGlobalAddressForCall - Emit the specified address to the code stream
/// assuming this is part of a function call, which is PC relative.
///
void Emitter::emitGlobalAddressForCall(GlobalValue *GV, bool DoesntNeedStub) {
MCE.addRelocation(MachineRelocation::getGV(MCE.getCurrentPCOffset(),
X86::reloc_pcrel_word, GV, 0,
DoesntNeedStub));
MCE.emitWordLE(0);
}
/// emitGlobalAddress - Emit the specified address to the code stream assuming
/// this is part of a "take the address of a global" instruction.
///
void Emitter::emitGlobalAddressForPtr(GlobalValue *GV, unsigned Reloc,
int Disp /* = 0 */,
unsigned PCAdj /* = 0 */) {
MCE.addRelocation(MachineRelocation::getGV(MCE.getCurrentPCOffset(), Reloc,
GV, PCAdj));
if (Reloc == X86::reloc_absolute_dword)
MCE.emitWordLE(0);
MCE.emitWordLE(Disp); // The relocated value will be added to the displacement
}
/// emitExternalSymbolAddress - Arrange for the address of an external symbol to
/// be emitted to the current location in the function, and allow it to be PC
/// relative.
void Emitter::emitExternalSymbolAddress(const char *ES, unsigned Reloc) {
MCE.addRelocation(MachineRelocation::getExtSym(MCE.getCurrentPCOffset(),
Reloc, ES));
if (Reloc == X86::reloc_absolute_dword)
MCE.emitWordLE(0);
MCE.emitWordLE(0);
}
/// emitConstPoolAddress - Arrange for the address of an constant pool
/// to be emitted to the current location in the function, and allow it to be PC
/// relative.
void Emitter::emitConstPoolAddress(unsigned CPI, unsigned Reloc,
int Disp /* = 0 */,
unsigned PCAdj /* = 0 */) {
MCE.addRelocation(MachineRelocation::getConstPool(MCE.getCurrentPCOffset(),
Reloc, CPI, PCAdj));
if (Reloc == X86::reloc_absolute_dword)
MCE.emitWordLE(0);
MCE.emitWordLE(Disp); // The relocated value will be added to the displacement
}
/// emitJumpTableAddress - Arrange for the address of a jump table to
/// be emitted to the current location in the function, and allow it to be PC
/// relative.
void Emitter::emitJumpTableAddress(unsigned JTI, unsigned Reloc,
unsigned PCAdj /* = 0 */) {
MCE.addRelocation(MachineRelocation::getJumpTable(MCE.getCurrentPCOffset(),
Reloc, JTI, PCAdj));
if (Reloc == X86::reloc_absolute_dword)
MCE.emitWordLE(0);
MCE.emitWordLE(0); // The relocated value will be added to the displacement
}
/// N86 namespace - Native X86 Register numbers... used by X86 backend.
///
namespace N86 {
enum {
EAX = 0, ECX = 1, EDX = 2, EBX = 3, ESP = 4, EBP = 5, ESI = 6, EDI = 7
};
}
// getX86RegNum - This function maps LLVM register identifiers to their X86
// specific numbering, which is used in various places encoding instructions.
//
unsigned Emitter::getX86RegNum(unsigned RegNo) {
switch(RegNo) {
case X86::RAX: case X86::EAX: case X86::AX: case X86::AL: return N86::EAX;
case X86::RCX: case X86::ECX: case X86::CX: case X86::CL: return N86::ECX;
case X86::RDX: case X86::EDX: case X86::DX: case X86::DL: return N86::EDX;
case X86::RBX: case X86::EBX: case X86::BX: case X86::BL: return N86::EBX;
case X86::RSP: case X86::ESP: case X86::SP: case X86::SPL: case X86::AH:
return N86::ESP;
case X86::RBP: case X86::EBP: case X86::BP: case X86::BPL: case X86::CH:
return N86::EBP;
case X86::RSI: case X86::ESI: case X86::SI: case X86::SIL: case X86::DH:
return N86::ESI;
case X86::RDI: case X86::EDI: case X86::DI: case X86::DIL: case X86::BH:
return N86::EDI;
case X86::R8: case X86::R8D: case X86::R8W: case X86::R8B:
return N86::EAX;
case X86::R9: case X86::R9D: case X86::R9W: case X86::R9B:
return N86::ECX;
case X86::R10: case X86::R10D: case X86::R10W: case X86::R10B:
return N86::EDX;
case X86::R11: case X86::R11D: case X86::R11W: case X86::R11B:
return N86::EBX;
case X86::R12: case X86::R12D: case X86::R12W: case X86::R12B:
return N86::ESP;
case X86::R13: case X86::R13D: case X86::R13W: case X86::R13B:
return N86::EBP;
case X86::R14: case X86::R14D: case X86::R14W: case X86::R14B:
return N86::ESI;
case X86::R15: case X86::R15D: case X86::R15W: case X86::R15B:
return N86::EDI;
case X86::ST0: case X86::ST1: case X86::ST2: case X86::ST3:
case X86::ST4: case X86::ST5: case X86::ST6: case X86::ST7:
return RegNo-X86::ST0;
case X86::XMM0: case X86::XMM1: case X86::XMM2: case X86::XMM3:
case X86::XMM4: case X86::XMM5: case X86::XMM6: case X86::XMM7:
return II->getRegisterInfo().getDwarfRegNum(RegNo) -
II->getRegisterInfo().getDwarfRegNum(X86::XMM0);
case X86::XMM8: case X86::XMM9: case X86::XMM10: case X86::XMM11:
case X86::XMM12: case X86::XMM13: case X86::XMM14: case X86::XMM15:
return II->getRegisterInfo().getDwarfRegNum(RegNo) -
II->getRegisterInfo().getDwarfRegNum(X86::XMM8);
default:
assert(MRegisterInfo::isVirtualRegister(RegNo) &&
"Unknown physical register!");
assert(0 && "Register allocator hasn't allocated reg correctly yet!");
return 0;
}
}
inline static unsigned char ModRMByte(unsigned Mod, unsigned RegOpcode,
unsigned RM) {
assert(Mod < 4 && RegOpcode < 8 && RM < 8 && "ModRM Fields out of range!");
return RM | (RegOpcode << 3) | (Mod << 6);
}
void Emitter::emitRegModRMByte(unsigned ModRMReg, unsigned RegOpcodeFld){
MCE.emitByte(ModRMByte(3, RegOpcodeFld, getX86RegNum(ModRMReg)));
}
void Emitter::emitSIBByte(unsigned SS, unsigned Index, unsigned Base) {
// SIB byte is in the same format as the ModRMByte...
MCE.emitByte(ModRMByte(SS, Index, Base));
}
void Emitter::emitConstant(uint64_t Val, unsigned Size) {
// Output the constant in little endian byte order...
for (unsigned i = 0; i != Size; ++i) {
MCE.emitByte(Val & 255);
Val >>= 8;
}
}
/// isDisp8 - Return true if this signed displacement fits in a 8-bit
/// sign-extended field.
static bool isDisp8(int Value) {
return Value == (signed char)Value;
}
void Emitter::emitDisplacementField(const MachineOperand *RelocOp,
int DispVal, unsigned PCAdj) {
// If this is a simple integer displacement that doesn't require a relocation,
// emit it now.
if (!RelocOp) {
emitConstant(DispVal, 4);
return;
}
// Otherwise, this is something that requires a relocation. Emit it as such
// now.
if (RelocOp->isGlobalAddress()) {
// In 64-bit static small code model, we could potentially emit absolute.
// But it's probably not beneficial.
// 89 05 00 00 00 00 mov %eax,0(%rip) # PC-relative
// 89 04 25 00 00 00 00 mov %eax,0x0 # Absolute
unsigned rt= Is64BitMode ? X86::reloc_pcrel_word : X86::reloc_absolute_word;
emitGlobalAddressForPtr(RelocOp->getGlobal(), rt,
RelocOp->getOffset(), PCAdj);
} else if (RelocOp->isConstantPoolIndex()) {
// Must be in 64-bit mode.
emitConstPoolAddress(RelocOp->getConstantPoolIndex(), X86::reloc_pcrel_word,
RelocOp->getOffset(), PCAdj);
} else if (RelocOp->isJumpTableIndex()) {
// Must be in 64-bit mode.
emitJumpTableAddress(RelocOp->getJumpTableIndex(), X86::reloc_pcrel_word,
PCAdj);
} else {
assert(0 && "Unknown value to relocate!");
}
}
void Emitter::emitMemModRMByte(const MachineInstr &MI,
unsigned Op, unsigned RegOpcodeField,
unsigned PCAdj) {
const MachineOperand &Op3 = MI.getOperand(Op+3);
int DispVal = 0;
const MachineOperand *DispForReloc = 0;
// Figure out what sort of displacement we have to handle here.
if (Op3.isGlobalAddress()) {
DispForReloc = &Op3;
} else if (Op3.isConstantPoolIndex()) {
if (Is64BitMode) {
DispForReloc = &Op3;
} else {
DispVal += MCE.getConstantPoolEntryAddress(Op3.getConstantPoolIndex());
DispVal += Op3.getOffset();
}
} else if (Op3.isJumpTableIndex()) {
if (Is64BitMode) {
DispForReloc = &Op3;
} else {
DispVal += MCE.getJumpTableEntryAddress(Op3.getJumpTableIndex());
}
} else {
DispVal = Op3.getImm();
}
const MachineOperand &Base = MI.getOperand(Op);
const MachineOperand &Scale = MI.getOperand(Op+1);
const MachineOperand &IndexReg = MI.getOperand(Op+2);
unsigned BaseReg = Base.getReg();
// Is a SIB byte needed?
if (IndexReg.getReg() == 0 &&
(BaseReg == 0 || getX86RegNum(BaseReg) != N86::ESP)) {
if (BaseReg == 0) { // Just a displacement?
// Emit special case [disp32] encoding
MCE.emitByte(ModRMByte(0, RegOpcodeField, 5));
emitDisplacementField(DispForReloc, DispVal, PCAdj);
} else {
unsigned BaseRegNo = getX86RegNum(BaseReg);
if (!DispForReloc && DispVal == 0 && BaseRegNo != N86::EBP) {
// Emit simple indirect register encoding... [EAX] f.e.
MCE.emitByte(ModRMByte(0, RegOpcodeField, BaseRegNo));
} else if (!DispForReloc && isDisp8(DispVal)) {
// Emit the disp8 encoding... [REG+disp8]
MCE.emitByte(ModRMByte(1, RegOpcodeField, BaseRegNo));
emitConstant(DispVal, 1);
} else {
// Emit the most general non-SIB encoding: [REG+disp32]
MCE.emitByte(ModRMByte(2, RegOpcodeField, BaseRegNo));
emitDisplacementField(DispForReloc, DispVal, PCAdj);
}
}
} else { // We need a SIB byte, so start by outputting the ModR/M byte first
assert(IndexReg.getReg() != X86::ESP &&
IndexReg.getReg() != X86::RSP && "Cannot use ESP as index reg!");
bool ForceDisp32 = false;
bool ForceDisp8 = false;
if (BaseReg == 0) {
// If there is no base register, we emit the special case SIB byte with
// MOD=0, BASE=5, to JUST get the index, scale, and displacement.
MCE.emitByte(ModRMByte(0, RegOpcodeField, 4));
ForceDisp32 = true;
} else if (DispForReloc) {
// Emit the normal disp32 encoding.
MCE.emitByte(ModRMByte(2, RegOpcodeField, 4));
ForceDisp32 = true;
} else if (DispVal == 0 && getX86RegNum(BaseReg) != N86::EBP) {
// Emit no displacement ModR/M byte
MCE.emitByte(ModRMByte(0, RegOpcodeField, 4));
} else if (isDisp8(DispVal)) {
// Emit the disp8 encoding...
MCE.emitByte(ModRMByte(1, RegOpcodeField, 4));
ForceDisp8 = true; // Make sure to force 8 bit disp if Base=EBP
} else {
// Emit the normal disp32 encoding...
MCE.emitByte(ModRMByte(2, RegOpcodeField, 4));
}
// Calculate what the SS field value should be...
static const unsigned SSTable[] = { ~0, 0, 1, ~0, 2, ~0, ~0, ~0, 3 };
unsigned SS = SSTable[Scale.getImm()];
if (BaseReg == 0) {
// Handle the SIB byte for the case where there is no base. The
// displacement has already been output.
assert(IndexReg.getReg() && "Index register must be specified!");
emitSIBByte(SS, getX86RegNum(IndexReg.getReg()), 5);
} else {
unsigned BaseRegNo = getX86RegNum(BaseReg);
unsigned IndexRegNo;
if (IndexReg.getReg())
IndexRegNo = getX86RegNum(IndexReg.getReg());
else
IndexRegNo = 4; // For example [ESP+1*<noreg>+4]
emitSIBByte(SS, IndexRegNo, BaseRegNo);
}
// Do we need to output a displacement?
if (ForceDisp8) {
emitConstant(DispVal, 1);
} else if (DispVal != 0 || ForceDisp32) {
emitDisplacementField(DispForReloc, DispVal, PCAdj);
}
}
}
static unsigned sizeOfImm(const TargetInstrDescriptor *Desc) {
switch (Desc->TSFlags & X86II::ImmMask) {
case X86II::Imm8: return 1;
case X86II::Imm16: return 2;
case X86II::Imm32: return 4;
case X86II::Imm64: return 8;
default: assert(0 && "Immediate size not set!");
return 0;
}
}
/// isX86_64ExtendedReg - Is the MachineOperand a x86-64 extended register?
/// e.g. r8, xmm8, etc.
bool Emitter::isX86_64ExtendedReg(const MachineOperand &MO) {
if (!MO.isRegister()) return false;
unsigned RegNo = MO.getReg();
int DWNum = II->getRegisterInfo().getDwarfRegNum(RegNo);
if (DWNum >= II->getRegisterInfo().getDwarfRegNum(X86::R8) &&
DWNum <= II->getRegisterInfo().getDwarfRegNum(X86::R15))
return true;
if (DWNum >= II->getRegisterInfo().getDwarfRegNum(X86::XMM8) &&
DWNum <= II->getRegisterInfo().getDwarfRegNum(X86::XMM15))
return true;
return false;
}
inline static bool isX86_64TruncToByte(unsigned oc) {
return (oc == X86::TRUNC_64to8 || oc == X86::TRUNC_32to8 ||
oc == X86::TRUNC_16to8);
}
inline static bool isX86_64NonExtLowByteReg(unsigned reg) {
return (reg == X86::SPL || reg == X86::BPL ||
reg == X86::SIL || reg == X86::DIL);
}
/// determineREX - Determine if the MachineInstr has to be encoded with a X86-64
/// REX prefix which specifies 1) 64-bit instructions, 2) non-default operand
/// size, and 3) use of X86-64 extended registers.
unsigned Emitter::determineREX(const MachineInstr &MI) {
unsigned REX = 0;
const TargetInstrDescriptor *Desc = MI.getInstrDescriptor();
unsigned Opcode = Desc->Opcode;
// Pseudo instructions do not need REX prefix byte.
if ((Desc->TSFlags & X86II::FormMask) == X86II::Pseudo)
return 0;
if (Desc->TSFlags & X86II::REX_W)
REX |= 1 << 3;
unsigned NumOps = Desc->numOperands;
if (NumOps) {
bool isTwoAddr = NumOps > 1 &&
Desc->getOperandConstraint(1, TOI::TIED_TO) != -1;
// If it accesses SPL, BPL, SIL, or DIL, then it requires a 0x40 REX prefix.
bool isTrunc8 = isX86_64TruncToByte(Opcode);
unsigned i = isTwoAddr ? 1 : 0;
for (unsigned e = NumOps; i != e; ++i) {
const MachineOperand& MO = MI.getOperand(i);
if (MO.isRegister()) {
unsigned Reg = MO.getReg();
// Trunc to byte are actually movb. The real source operand is the low
// byte of the register.
if (isTrunc8 && i == 1)
Reg = getX86SubSuperRegister(Reg, MVT::i8);
if (isX86_64NonExtLowByteReg(Reg))
REX |= 0x40;
}
}
switch (Desc->TSFlags & X86II::FormMask) {
case X86II::MRMInitReg:
if (isX86_64ExtendedReg(MI.getOperand(0)))
REX |= (1 << 0) | (1 << 2);
break;
case X86II::MRMSrcReg: {
if (isX86_64ExtendedReg(MI.getOperand(0)))
REX |= 1 << 2;
i = isTwoAddr ? 2 : 1;
for (unsigned e = NumOps; i != e; ++i) {
const MachineOperand& MO = MI.getOperand(i);
if (isX86_64ExtendedReg(MO))
REX |= 1 << 0;
}
break;
}
case X86II::MRMSrcMem: {
if (isX86_64ExtendedReg(MI.getOperand(0)))
REX |= 1 << 2;
unsigned Bit = 0;
i = isTwoAddr ? 2 : 1;
for (; i != NumOps; ++i) {
const MachineOperand& MO = MI.getOperand(i);
if (MO.isRegister()) {
if (isX86_64ExtendedReg(MO))
REX |= 1 << Bit;
Bit++;
}
}
break;
}
case X86II::MRM0m: case X86II::MRM1m:
case X86II::MRM2m: case X86II::MRM3m:
case X86II::MRM4m: case X86II::MRM5m:
case X86II::MRM6m: case X86II::MRM7m:
case X86II::MRMDestMem: {
unsigned e = isTwoAddr ? 5 : 4;
i = isTwoAddr ? 1 : 0;
if (NumOps > e && isX86_64ExtendedReg(MI.getOperand(e)))
REX |= 1 << 2;
unsigned Bit = 0;
for (; i != e; ++i) {
const MachineOperand& MO = MI.getOperand(i);
if (MO.isRegister()) {
if (isX86_64ExtendedReg(MO))
REX |= 1 << Bit;
Bit++;
}
}
break;
}
default: {
if (isX86_64ExtendedReg(MI.getOperand(0)))
REX |= 1 << 0;
i = isTwoAddr ? 2 : 1;
for (unsigned e = NumOps; i != e; ++i) {
const MachineOperand& MO = MI.getOperand(i);
if (isX86_64ExtendedReg(MO))
REX |= 1 << 2;
}
break;
}
}
}
return REX;
}
void Emitter::emitInstruction(const MachineInstr &MI) {
NumEmitted++; // Keep track of the # of mi's emitted
const TargetInstrDescriptor *Desc = MI.getInstrDescriptor();
unsigned Opcode = Desc->Opcode;
// Emit the repeat opcode prefix as needed.
if ((Desc->TSFlags & X86II::Op0Mask) == X86II::REP) MCE.emitByte(0xF3);
// Emit the operand size opcode prefix as needed.
if (Desc->TSFlags & X86II::OpSize) MCE.emitByte(0x66);
// Emit the address size opcode prefix as needed.
if (Desc->TSFlags & X86II::AdSize) MCE.emitByte(0x67);
bool Need0FPrefix = false;
switch (Desc->TSFlags & X86II::Op0Mask) {
case X86II::TB:
Need0FPrefix = true; // Two-byte opcode prefix
break;
case X86II::REP: break; // already handled.
case X86II::XS: // F3 0F
MCE.emitByte(0xF3);
Need0FPrefix = true;
break;
case X86II::XD: // F2 0F
MCE.emitByte(0xF2);
Need0FPrefix = true;
break;
case X86II::D8: case X86II::D9: case X86II::DA: case X86II::DB:
case X86II::DC: case X86II::DD: case X86II::DE: case X86II::DF:
MCE.emitByte(0xD8+
(((Desc->TSFlags & X86II::Op0Mask)-X86II::D8)
>> X86II::Op0Shift));
break; // Two-byte opcode prefix
default: assert(0 && "Invalid prefix!");
case 0: break; // No prefix!
}
if (Is64BitMode) {
// REX prefix
unsigned REX = determineREX(MI);
if (REX)
MCE.emitByte(0x40 | REX);
}
// 0x0F escape code must be emitted just before the opcode.
if (Need0FPrefix)
MCE.emitByte(0x0F);
// If this is a two-address instruction, skip one of the register operands.
unsigned NumOps = Desc->numOperands;
unsigned CurOp = 0;
if (NumOps > 1 && Desc->getOperandConstraint(1, TOI::TIED_TO) != -1)
CurOp++;
unsigned char BaseOpcode = II->getBaseOpcodeFor(Desc);
switch (Desc->TSFlags & X86II::FormMask) {
default: assert(0 && "Unknown FormMask value in X86 MachineCodeEmitter!");
case X86II::Pseudo:
#ifndef NDEBUG
switch (Opcode) {
default:
assert(0 && "psuedo instructions should be removed before code emission");
case TargetInstrInfo::INLINEASM:
assert(0 && "JIT does not support inline asm!\n");
case TargetInstrInfo::LABEL:
assert(0 && "JIT does not support meta labels!\n");
case X86::IMPLICIT_USE:
case X86::IMPLICIT_DEF:
case X86::IMPLICIT_DEF_GR8:
case X86::IMPLICIT_DEF_GR16:
case X86::IMPLICIT_DEF_GR32:
case X86::IMPLICIT_DEF_GR64:
case X86::IMPLICIT_DEF_FR32:
case X86::IMPLICIT_DEF_FR64:
case X86::IMPLICIT_DEF_VR64:
case X86::IMPLICIT_DEF_VR128:
case X86::FP_REG_KILL:
break;
}
#endif
CurOp = NumOps;
break;
case X86II::RawFrm:
MCE.emitByte(BaseOpcode);
if (CurOp != NumOps) {
const MachineOperand &MO = MI.getOperand(CurOp++);
if (MO.isMachineBasicBlock()) {
emitPCRelativeBlockAddress(MO.getMachineBasicBlock());
} else if (MO.isGlobalAddress()) {
bool NeedStub = Is64BitMode ||
Opcode == X86::TAILJMPd ||
Opcode == X86::TAILJMPr || Opcode == X86::TAILJMPm;
emitGlobalAddressForCall(MO.getGlobal(), !NeedStub);
} else if (MO.isExternalSymbol()) {
emitExternalSymbolAddress(MO.getSymbolName(), X86::reloc_pcrel_word);
} else if (MO.isImmediate()) {
emitConstant(MO.getImm(), sizeOfImm(Desc));
} else {
assert(0 && "Unknown RawFrm operand!");
}
}
break;
case X86II::AddRegFrm:
MCE.emitByte(BaseOpcode + getX86RegNum(MI.getOperand(CurOp++).getReg()));
if (CurOp != NumOps) {
const MachineOperand &MO1 = MI.getOperand(CurOp++);
unsigned Size = sizeOfImm(Desc);
if (MO1.isImmediate())
emitConstant(MO1.getImm(), Size);
else {
unsigned rt = Is64BitMode ? X86::reloc_pcrel_word : X86::reloc_absolute_word;
if (Opcode == X86::MOV64ri)
rt = X86::reloc_absolute_dword; // FIXME: add X86II flag?
if (MO1.isGlobalAddress())
emitGlobalAddressForPtr(MO1.getGlobal(), rt, MO1.getOffset());
else if (MO1.isExternalSymbol())
emitExternalSymbolAddress(MO1.getSymbolName(), rt);
else if (MO1.isConstantPoolIndex())
emitConstPoolAddress(MO1.getConstantPoolIndex(), rt);
else if (MO1.isJumpTableIndex())
emitJumpTableAddress(MO1.getJumpTableIndex(), rt);
}
}
break;
case X86II::MRMDestReg: {
MCE.emitByte(BaseOpcode);
emitRegModRMByte(MI.getOperand(CurOp).getReg(),
getX86RegNum(MI.getOperand(CurOp+1).getReg()));
CurOp += 2;
if (CurOp != NumOps)
emitConstant(MI.getOperand(CurOp++).getImm(), sizeOfImm(Desc));
break;
}
case X86II::MRMDestMem: {
MCE.emitByte(BaseOpcode);
emitMemModRMByte(MI, CurOp, getX86RegNum(MI.getOperand(CurOp+4).getReg()));
CurOp += 5;
if (CurOp != NumOps)
emitConstant(MI.getOperand(CurOp++).getImm(), sizeOfImm(Desc));
break;
}
case X86II::MRMSrcReg:
MCE.emitByte(BaseOpcode);
emitRegModRMByte(MI.getOperand(CurOp+1).getReg(),
getX86RegNum(MI.getOperand(CurOp).getReg()));
CurOp += 2;
if (CurOp != NumOps)
emitConstant(MI.getOperand(CurOp++).getImm(), sizeOfImm(Desc));
break;
case X86II::MRMSrcMem: {
unsigned PCAdj = (CurOp+5 != NumOps) ? sizeOfImm(Desc) : 0;
MCE.emitByte(BaseOpcode);
emitMemModRMByte(MI, CurOp+1, getX86RegNum(MI.getOperand(CurOp).getReg()),
PCAdj);
CurOp += 5;
if (CurOp != NumOps)
emitConstant(MI.getOperand(CurOp++).getImm(), sizeOfImm(Desc));
break;
}
case X86II::MRM0r: case X86II::MRM1r:
case X86II::MRM2r: case X86II::MRM3r:
case X86II::MRM4r: case X86II::MRM5r:
case X86II::MRM6r: case X86II::MRM7r:
MCE.emitByte(BaseOpcode);
emitRegModRMByte(MI.getOperand(CurOp++).getReg(),
(Desc->TSFlags & X86II::FormMask)-X86II::MRM0r);
if (CurOp != NumOps) {
const MachineOperand &MO1 = MI.getOperand(CurOp++);
unsigned Size = sizeOfImm(Desc);
if (MO1.isImmediate())
emitConstant(MO1.getImm(), Size);
else {
unsigned rt = Is64BitMode ? X86::reloc_pcrel_word
: X86::reloc_absolute_word;
if (Opcode == X86::MOV64ri32)
rt = X86::reloc_absolute_word; // FIXME: add X86II flag?
if (MO1.isGlobalAddress())
emitGlobalAddressForPtr(MO1.getGlobal(), rt, MO1.getOffset());
else if (MO1.isExternalSymbol())
emitExternalSymbolAddress(MO1.getSymbolName(), rt);
else if (MO1.isConstantPoolIndex())
emitConstPoolAddress(MO1.getConstantPoolIndex(), rt);
else if (MO1.isJumpTableIndex())
emitJumpTableAddress(MO1.getJumpTableIndex(), rt);
}
}
break;
case X86II::MRM0m: case X86II::MRM1m:
case X86II::MRM2m: case X86II::MRM3m:
case X86II::MRM4m: case X86II::MRM5m:
case X86II::MRM6m: case X86II::MRM7m: {
unsigned PCAdj = (CurOp+4 != NumOps) ?
(MI.getOperand(CurOp+4).isImmediate() ? sizeOfImm(Desc) : 4) : 0;
MCE.emitByte(BaseOpcode);
emitMemModRMByte(MI, CurOp, (Desc->TSFlags & X86II::FormMask)-X86II::MRM0m,
PCAdj);
CurOp += 4;
if (CurOp != NumOps) {
const MachineOperand &MO = MI.getOperand(CurOp++);
unsigned Size = sizeOfImm(Desc);
if (MO.isImmediate())
emitConstant(MO.getImm(), Size);
else {
unsigned rt = Is64BitMode ? X86::reloc_pcrel_word
: X86::reloc_absolute_word;
if (Opcode == X86::MOV64mi32)
rt = X86::reloc_absolute_word; // FIXME: add X86II flag?
if (MO.isGlobalAddress())
emitGlobalAddressForPtr(MO.getGlobal(), rt, MO.getOffset());
else if (MO.isExternalSymbol())
emitExternalSymbolAddress(MO.getSymbolName(), rt);
else if (MO.isConstantPoolIndex())
emitConstPoolAddress(MO.getConstantPoolIndex(), rt);
else if (MO.isJumpTableIndex())
emitJumpTableAddress(MO.getJumpTableIndex(), rt);
}
}
break;
}
case X86II::MRMInitReg:
MCE.emitByte(BaseOpcode);
// Duplicate register, used by things like MOV8r0 (aka xor reg,reg).
emitRegModRMByte(MI.getOperand(CurOp).getReg(),
getX86RegNum(MI.getOperand(CurOp).getReg()));
++CurOp;
break;
}
assert((Desc->Flags & M_VARIABLE_OPS) != 0 ||
CurOp == NumOps && "Unknown encoding!");
}
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