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llvm-project/llvm/lib/Target/X86/X86CodeEmitter.cpp

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//===-- X86/X86CodeEmitter.cpp - Convert X86 code to machine code ---------===//
//
// The LLVM Compiler Infrastructure
//
// This file 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 "X86JITInfo.h"
#include "X86Subtarget.h"
#include "X86TargetMachine.h"
#include "X86Relocations.h"
#include "X86.h"
#include "llvm/LLVMContext.h"
#include "llvm/PassManager.h"
#include "llvm/CodeGen/JITCodeEmitter.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/Function.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/MC/MCCodeEmitter.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCInst.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetOptions.h"
using namespace llvm;
STATISTIC(NumEmitted, "Number of machine instructions emitted");
namespace {
template<class CodeEmitter>
class Emitter : public MachineFunctionPass {
const X86InstrInfo *II;
const TargetData *TD;
X86TargetMachine &TM;
CodeEmitter &MCE;
MachineModuleInfo *MMI;
intptr_t PICBaseOffset;
bool Is64BitMode;
bool IsPIC;
public:
static char ID;
explicit Emitter(X86TargetMachine &tm, CodeEmitter &mce)
: MachineFunctionPass(&ID), II(0), TD(0), TM(tm),
MCE(mce), PICBaseOffset(0), Is64BitMode(false),
IsPIC(TM.getRelocationModel() == Reloc::PIC_) {}
Emitter(X86TargetMachine &tm, CodeEmitter &mce,
const X86InstrInfo &ii, const TargetData &td, bool is64)
: MachineFunctionPass(&ID), II(&ii), TD(&td), TM(tm),
MCE(mce), PICBaseOffset(0), Is64BitMode(is64),
IsPIC(TM.getRelocationModel() == Reloc::PIC_) {}
bool runOnMachineFunction(MachineFunction &MF);
virtual const char *getPassName() const {
return "X86 Machine Code Emitter";
}
void emitInstruction(const MachineInstr &MI,
const TargetInstrDesc *Desc);
void getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesAll();
AU.addRequired<MachineModuleInfo>();
MachineFunctionPass::getAnalysisUsage(AU);
}
private:
void emitPCRelativeBlockAddress(MachineBasicBlock *MBB);
void emitGlobalAddress(const GlobalValue *GV, unsigned Reloc,
intptr_t Disp = 0, intptr_t PCAdj = 0,
bool Indirect = false);
void emitExternalSymbolAddress(const char *ES, unsigned Reloc);
void emitConstPoolAddress(unsigned CPI, unsigned Reloc, intptr_t Disp = 0,
intptr_t PCAdj = 0);
void emitJumpTableAddress(unsigned JTI, unsigned Reloc,
intptr_t PCAdj = 0);
void emitDisplacementField(const MachineOperand *RelocOp, int DispVal,
intptr_t Adj = 0, bool IsPCRel = true);
void emitRegModRMByte(unsigned ModRMReg, unsigned RegOpcodeField);
void emitRegModRMByte(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,
intptr_t PCAdj = 0);
unsigned getX86RegNum(unsigned RegNo) const;
};
template<class CodeEmitter>
char Emitter<CodeEmitter>::ID = 0;
} // end anonymous namespace.
/// createX86CodeEmitterPass - Return a pass that emits the collected X86 code
/// to the specified templated MachineCodeEmitter object.
FunctionPass *llvm::createX86JITCodeEmitterPass(X86TargetMachine &TM,
JITCodeEmitter &JCE) {
return new Emitter<JITCodeEmitter>(TM, JCE);
}
template<class CodeEmitter>
bool Emitter<CodeEmitter>::runOnMachineFunction(MachineFunction &MF) {
MMI = &getAnalysis<MachineModuleInfo>();
MCE.setModuleInfo(MMI);
II = TM.getInstrInfo();
TD = TM.getTargetData();
Is64BitMode = TM.getSubtarget<X86Subtarget>().is64Bit();
IsPIC = TM.getRelocationModel() == Reloc::PIC_;
do {
DEBUG(dbgs() << "JITTing function '"
<< MF.getFunction()->getName() << "'\n");
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) {
const TargetInstrDesc &Desc = I->getDesc();
emitInstruction(*I, &Desc);
// MOVPC32r is basically a call plus a pop instruction.
if (Desc.getOpcode() == X86::MOVPC32r)
emitInstruction(*I, &II->get(X86::POP32r));
++NumEmitted; // Keep track of the # of mi's emitted
}
}
} while (MCE.finishFunction(MF));
return false;
}
/// 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.
static unsigned determineREX(const MachineInstr &MI) {
unsigned REX = 0;
const TargetInstrDesc &Desc = MI.getDesc();
// 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.getNumOperands();
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.
unsigned i = isTwoAddr ? 1 : 0;
for (unsigned e = NumOps; i != e; ++i) {
const MachineOperand& MO = MI.getOperand(i);
if (MO.isReg()) {
unsigned Reg = MO.getReg();
if (X86InstrInfo::isX86_64NonExtLowByteReg(Reg))
REX |= 0x40;
}
}
switch (Desc.TSFlags & X86II::FormMask) {
case X86II::MRMInitReg:
if (X86InstrInfo::isX86_64ExtendedReg(MI.getOperand(0)))
REX |= (1 << 0) | (1 << 2);
break;
case X86II::MRMSrcReg: {
if (X86InstrInfo::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 (X86InstrInfo::isX86_64ExtendedReg(MO))
REX |= 1 << 0;
}
break;
}
case X86II::MRMSrcMem: {
if (X86InstrInfo::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.isReg()) {
if (X86InstrInfo::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 ? X86::AddrNumOperands+1 : X86::AddrNumOperands);
i = isTwoAddr ? 1 : 0;
if (NumOps > e && X86InstrInfo::isX86_64ExtendedReg(MI.getOperand(e)))
REX |= 1 << 2;
unsigned Bit = 0;
for (; i != e; ++i) {
const MachineOperand& MO = MI.getOperand(i);
if (MO.isReg()) {
if (X86InstrInfo::isX86_64ExtendedReg(MO))
REX |= 1 << Bit;
Bit++;
}
}
break;
}
default: {
if (X86InstrInfo::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 (X86InstrInfo::isX86_64ExtendedReg(MO))
REX |= 1 << 2;
}
break;
}
}
}
return REX;
}
/// emitPCRelativeBlockAddress - This method keeps track of the information
/// necessary to resolve the address of this block later and emits a dummy
/// value.
///
template<class CodeEmitter>
void Emitter<CodeEmitter>::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);
}
/// emitGlobalAddress - Emit the specified address to the code stream assuming
/// this is part of a "take the address of a global" instruction.
///
template<class CodeEmitter>
void Emitter<CodeEmitter>::emitGlobalAddress(const GlobalValue *GV,
unsigned Reloc,
intptr_t Disp /* = 0 */,
intptr_t PCAdj /* = 0 */,
bool Indirect /* = false */) {
intptr_t RelocCST = Disp;
if (Reloc == X86::reloc_picrel_word)
RelocCST = PICBaseOffset;
else if (Reloc == X86::reloc_pcrel_word)
RelocCST = PCAdj;
MachineRelocation MR = Indirect
? MachineRelocation::getIndirectSymbol(MCE.getCurrentPCOffset(), Reloc,
const_cast<GlobalValue *>(GV),
RelocCST, false)
: MachineRelocation::getGV(MCE.getCurrentPCOffset(), Reloc,
const_cast<GlobalValue *>(GV), RelocCST, false);
MCE.addRelocation(MR);
// The relocated value will be added to the displacement
if (Reloc == X86::reloc_absolute_dword)
MCE.emitDWordLE(Disp);
else
MCE.emitWordLE((int32_t)Disp);
}
/// 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.
template<class CodeEmitter>
void Emitter<CodeEmitter>::emitExternalSymbolAddress(const char *ES,
unsigned Reloc) {
intptr_t RelocCST = (Reloc == X86::reloc_picrel_word) ? PICBaseOffset : 0;
// X86 never needs stubs because instruction selection will always pick
// an instruction sequence that is large enough to hold any address
// to a symbol.
// (see X86ISelLowering.cpp, near 2039: X86TargetLowering::LowerCall)
bool NeedStub = false;
MCE.addRelocation(MachineRelocation::getExtSym(MCE.getCurrentPCOffset(),
Reloc, ES, RelocCST,
0, NeedStub));
if (Reloc == X86::reloc_absolute_dword)
MCE.emitDWordLE(0);
else
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.
template<class CodeEmitter>
void Emitter<CodeEmitter>::emitConstPoolAddress(unsigned CPI, unsigned Reloc,
intptr_t Disp /* = 0 */,
intptr_t PCAdj /* = 0 */) {
intptr_t RelocCST = 0;
if (Reloc == X86::reloc_picrel_word)
RelocCST = PICBaseOffset;
else if (Reloc == X86::reloc_pcrel_word)
RelocCST = PCAdj;
MCE.addRelocation(MachineRelocation::getConstPool(MCE.getCurrentPCOffset(),
Reloc, CPI, RelocCST));
// The relocated value will be added to the displacement
if (Reloc == X86::reloc_absolute_dword)
MCE.emitDWordLE(Disp);
else
MCE.emitWordLE((int32_t)Disp);
}
/// 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.
template<class CodeEmitter>
void Emitter<CodeEmitter>::emitJumpTableAddress(unsigned JTI, unsigned Reloc,
intptr_t PCAdj /* = 0 */) {
intptr_t RelocCST = 0;
if (Reloc == X86::reloc_picrel_word)
RelocCST = PICBaseOffset;
else if (Reloc == X86::reloc_pcrel_word)
RelocCST = PCAdj;
MCE.addRelocation(MachineRelocation::getJumpTable(MCE.getCurrentPCOffset(),
Reloc, JTI, RelocCST));
// The relocated value will be added to the displacement
if (Reloc == X86::reloc_absolute_dword)
MCE.emitDWordLE(0);
else
MCE.emitWordLE(0);
}
template<class CodeEmitter>
unsigned Emitter<CodeEmitter>::getX86RegNum(unsigned RegNo) const {
return X86RegisterInfo::getX86RegNum(RegNo);
}
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);
}
template<class CodeEmitter>
void Emitter<CodeEmitter>::emitRegModRMByte(unsigned ModRMReg,
unsigned RegOpcodeFld){
MCE.emitByte(ModRMByte(3, RegOpcodeFld, getX86RegNum(ModRMReg)));
}
template<class CodeEmitter>
void Emitter<CodeEmitter>::emitRegModRMByte(unsigned RegOpcodeFld) {
MCE.emitByte(ModRMByte(3, RegOpcodeFld, 0));
}
template<class CodeEmitter>
void Emitter<CodeEmitter>::emitSIBByte(unsigned SS,
unsigned Index,
unsigned Base) {
// SIB byte is in the same format as the ModRMByte...
MCE.emitByte(ModRMByte(SS, Index, Base));
}
template<class CodeEmitter>
void Emitter<CodeEmitter>::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;
}
static bool gvNeedsNonLazyPtr(const MachineOperand &GVOp,
const TargetMachine &TM) {
// For Darwin-64, simulate the linktime GOT by using the same non-lazy-pointer
// mechanism as 32-bit mode.
if (TM.getSubtarget<X86Subtarget>().is64Bit() &&
!TM.getSubtarget<X86Subtarget>().isTargetDarwin())
return false;
// Return true if this is a reference to a stub containing the address of the
// global, not the global itself.
return isGlobalStubReference(GVOp.getTargetFlags());
}
template<class CodeEmitter>
void Emitter<CodeEmitter>::emitDisplacementField(const MachineOperand *RelocOp,
int DispVal,
intptr_t Adj /* = 0 */,
bool IsPCRel /* = true */) {
// 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.
unsigned RelocType = Is64BitMode ?
(IsPCRel ? X86::reloc_pcrel_word : X86::reloc_absolute_word_sext)
: (IsPIC ? X86::reloc_picrel_word : X86::reloc_absolute_word);
if (RelocOp->isGlobal()) {
// In 64-bit static small code model, we could potentially emit absolute.
// But it's probably not beneficial. If the MCE supports using RIP directly
// do it, otherwise fallback to absolute (this is determined by IsPCRel).
// 89 05 00 00 00 00 mov %eax,0(%rip) # PC-relative
// 89 04 25 00 00 00 00 mov %eax,0x0 # Absolute
bool Indirect = gvNeedsNonLazyPtr(*RelocOp, TM);
emitGlobalAddress(RelocOp->getGlobal(), RelocType, RelocOp->getOffset(),
Adj, Indirect);
} else if (RelocOp->isSymbol()) {
emitExternalSymbolAddress(RelocOp->getSymbolName(), RelocType);
} else if (RelocOp->isCPI()) {
emitConstPoolAddress(RelocOp->getIndex(), RelocType,
RelocOp->getOffset(), Adj);
} else {
assert(RelocOp->isJTI() && "Unexpected machine operand!");
emitJumpTableAddress(RelocOp->getIndex(), RelocType, Adj);
}
}
template<class CodeEmitter>
void Emitter<CodeEmitter>::emitMemModRMByte(const MachineInstr &MI,
unsigned Op,unsigned RegOpcodeField,
intptr_t 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.isGlobal()) {
DispForReloc = &Op3;
} else if (Op3.isSymbol()) {
DispForReloc = &Op3;
} else if (Op3.isCPI()) {
if (!MCE.earlyResolveAddresses() || Is64BitMode || IsPIC) {
DispForReloc = &Op3;
} else {
DispVal += MCE.getConstantPoolEntryAddress(Op3.getIndex());
DispVal += Op3.getOffset();
}
} else if (Op3.isJTI()) {
if (!MCE.earlyResolveAddresses() || Is64BitMode || IsPIC) {
DispForReloc = &Op3;
} else {
DispVal += MCE.getJumpTableEntryAddress(Op3.getIndex());
}
} 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();
// Handle %rip relative addressing.
if (BaseReg == X86::RIP ||
(Is64BitMode && DispForReloc)) { // [disp32+RIP] in X86-64 mode
assert(IndexReg.getReg() == 0 && Is64BitMode &&
"Invalid rip-relative address");
MCE.emitByte(ModRMByte(0, RegOpcodeField, 5));
emitDisplacementField(DispForReloc, DispVal, PCAdj, true);
return;
}
// Indicate that the displacement will use an pcrel or absolute reference
// by default. MCEs able to resolve addresses on-the-fly use pcrel by default
// while others, unless explicit asked to use RIP, use absolute references.
bool IsPCRel = MCE.earlyResolveAddresses() ? true : false;
// Is a SIB byte needed?
// If no BaseReg, issue a RIP relative instruction only if the MCE can
// resolve addresses on-the-fly, otherwise use SIB (Intel Manual 2A, table
// 2-7) and absolute references.
unsigned BaseRegNo = -1U;
if (BaseReg != 0 && BaseReg != X86::RIP)
BaseRegNo = getX86RegNum(BaseReg);
if (// The SIB byte must be used if there is an index register.
IndexReg.getReg() == 0 &&
// The SIB byte must be used if the base is ESP/RSP/R12, all of which
// encode to an R/M value of 4, which indicates that a SIB byte is
// present.
BaseRegNo != N86::ESP &&
// If there is no base register and we're in 64-bit mode, we need a SIB
// byte to emit an addr that is just 'disp32' (the non-RIP relative form).
(!Is64BitMode || BaseReg != 0)) {
if (BaseReg == 0 || // [disp32] in X86-32 mode
BaseReg == X86::RIP) { // [disp32+RIP] in X86-64 mode
MCE.emitByte(ModRMByte(0, RegOpcodeField, 5));
emitDisplacementField(DispForReloc, DispVal, PCAdj, true);
return;
}
// If the base is not EBP/ESP and there is no displacement, use simple
// indirect register encoding, this handles addresses like [EAX]. The
// encoding for [EBP] with no displacement means [disp32] so we handle it
// by emitting a displacement of 0 below.
if (!DispForReloc && DispVal == 0 && BaseRegNo != N86::EBP) {
MCE.emitByte(ModRMByte(0, RegOpcodeField, BaseRegNo));
return;
}
// Otherwise, if the displacement fits in a byte, encode as [REG+disp8].
if (!DispForReloc && isDisp8(DispVal)) {
MCE.emitByte(ModRMByte(1, RegOpcodeField, BaseRegNo));
emitConstant(DispVal, 1);
return;
}
// Otherwise, emit the most general non-SIB encoding: [REG+disp32]
MCE.emitByte(ModRMByte(2, RegOpcodeField, BaseRegNo));
emitDisplacementField(DispForReloc, DispVal, PCAdj, IsPCRel);
return;
}
// Otherwise 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=4, 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 && BaseRegNo != 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, see Intel
// Manual 2A, table 2-7. The displacement has already been output.
unsigned IndexRegNo;
if (IndexReg.getReg())
IndexRegNo = getX86RegNum(IndexReg.getReg());
else // Examples: [ESP+1*<noreg>+4] or [scaled idx]+disp32 (MOD=0,BASE=5)
IndexRegNo = 4;
emitSIBByte(SS, IndexRegNo, 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, IsPCRel);
}
}
template<class CodeEmitter>
void Emitter<CodeEmitter>::emitInstruction(const MachineInstr &MI,
const TargetInstrDesc *Desc) {
DEBUG(dbgs() << MI);
MCE.processDebugLoc(MI.getDebugLoc(), true);
unsigned Opcode = Desc->Opcode;
// Emit the lock opcode prefix as needed.
if (Desc->TSFlags & X86II::LOCK)
MCE.emitByte(0xF0);
// Emit segment override opcode prefix as needed.
switch (Desc->TSFlags & X86II::SegOvrMask) {
case X86II::FS:
MCE.emitByte(0x64);
break;
case X86II::GS:
MCE.emitByte(0x65);
break;
default: llvm_unreachable("Invalid segment!");
case 0: break; // No segment override!
}
// 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: // Two-byte opcode prefix
case X86II::T8: // 0F 38
case X86II::TA: // 0F 3A
Need0FPrefix = true;
break;
case X86II::TF: // F2 0F 38
MCE.emitByte(0xF2);
Need0FPrefix = true;
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: llvm_unreachable("Invalid prefix!");
case 0: break; // No prefix!
}
// Handle REX prefix.
if (Is64BitMode) {
if (unsigned REX = determineREX(MI))
MCE.emitByte(0x40 | REX);
}
// 0x0F escape code must be emitted just before the opcode.
if (Need0FPrefix)
MCE.emitByte(0x0F);
switch (Desc->TSFlags & X86II::Op0Mask) {
case X86II::TF: // F2 0F 38
case X86II::T8: // 0F 38
MCE.emitByte(0x38);
break;
case X86II::TA: // 0F 3A
MCE.emitByte(0x3A);
break;
}
// If this is a two-address instruction, skip one of the register operands.
unsigned NumOps = Desc->getNumOperands();
unsigned CurOp = 0;
if (NumOps > 1 && Desc->getOperandConstraint(1, TOI::TIED_TO) != -1)
++CurOp;
else if (NumOps > 2 && Desc->getOperandConstraint(NumOps-1, TOI::TIED_TO)== 0)
// Skip the last source operand that is tied_to the dest reg. e.g. LXADD32
--NumOps;
unsigned char BaseOpcode = X86II::getBaseOpcodeFor(Desc->TSFlags);
switch (Desc->TSFlags & X86II::FormMask) {
default:
llvm_unreachable("Unknown FormMask value in X86 MachineCodeEmitter!");
case X86II::Pseudo:
// Remember the current PC offset, this is the PIC relocation
// base address.
switch (Opcode) {
default:
llvm_unreachable("psuedo instructions should be removed before code"
" emission");
break;
case TargetOpcode::INLINEASM:
// We allow inline assembler nodes with empty bodies - they can
// implicitly define registers, which is ok for JIT.
if (MI.getOperand(0).getSymbolName()[0])
report_fatal_error("JIT does not support inline asm!");
break;
case TargetOpcode::PROLOG_LABEL:
case TargetOpcode::GC_LABEL:
case TargetOpcode::EH_LABEL:
MCE.emitLabel(MI.getOperand(0).getMCSymbol());
break;
case TargetOpcode::IMPLICIT_DEF:
case TargetOpcode::KILL:
break;
case X86::MOVPC32r: {
// This emits the "call" portion of this pseudo instruction.
MCE.emitByte(BaseOpcode);
emitConstant(0, X86II::getSizeOfImm(Desc->TSFlags));
// Remember PIC base.
PICBaseOffset = (intptr_t) MCE.getCurrentPCOffset();
X86JITInfo *JTI = TM.getJITInfo();
JTI->setPICBase(MCE.getCurrentPCValue());
break;
}
}
CurOp = NumOps;
break;
case X86II::RawFrm: {
MCE.emitByte(BaseOpcode);
if (CurOp == NumOps)
break;
const MachineOperand &MO = MI.getOperand(CurOp++);
DEBUG(dbgs() << "RawFrm CurOp " << CurOp << "\n");
DEBUG(dbgs() << "isMBB " << MO.isMBB() << "\n");
DEBUG(dbgs() << "isGlobal " << MO.isGlobal() << "\n");
DEBUG(dbgs() << "isSymbol " << MO.isSymbol() << "\n");
DEBUG(dbgs() << "isImm " << MO.isImm() << "\n");
if (MO.isMBB()) {
emitPCRelativeBlockAddress(MO.getMBB());
break;
}
if (MO.isGlobal()) {
emitGlobalAddress(MO.getGlobal(), X86::reloc_pcrel_word,
MO.getOffset(), 0);
break;
}
if (MO.isSymbol()) {
emitExternalSymbolAddress(MO.getSymbolName(), X86::reloc_pcrel_word);
break;
}
// FIXME: Only used by hackish MCCodeEmitter, remove when dead.
if (MO.isJTI()) {
emitJumpTableAddress(MO.getIndex(), X86::reloc_pcrel_word);
break;
}
assert(MO.isImm() && "Unknown RawFrm operand!");
if (Opcode == X86::CALLpcrel32 || Opcode == X86::CALL64pcrel32) {
// Fix up immediate operand for pc relative calls.
intptr_t Imm = (intptr_t)MO.getImm();
Imm = Imm - MCE.getCurrentPCValue() - 4;
emitConstant(Imm, X86II::getSizeOfImm(Desc->TSFlags));
} else
emitConstant(MO.getImm(), X86II::getSizeOfImm(Desc->TSFlags));
break;
}
case X86II::AddRegFrm: {
MCE.emitByte(BaseOpcode + getX86RegNum(MI.getOperand(CurOp++).getReg()));
if (CurOp == NumOps)
break;
const MachineOperand &MO1 = MI.getOperand(CurOp++);
unsigned Size = X86II::getSizeOfImm(Desc->TSFlags);
if (MO1.isImm()) {
emitConstant(MO1.getImm(), Size);
break;
}
unsigned rt = Is64BitMode ? X86::reloc_pcrel_word
: (IsPIC ? X86::reloc_picrel_word : X86::reloc_absolute_word);
if (Opcode == X86::MOV64ri64i32)
rt = X86::reloc_absolute_word; // FIXME: add X86II flag?
// This should not occur on Darwin for relocatable objects.
if (Opcode == X86::MOV64ri)
rt = X86::reloc_absolute_dword; // FIXME: add X86II flag?
if (MO1.isGlobal()) {
bool Indirect = gvNeedsNonLazyPtr(MO1, TM);
emitGlobalAddress(MO1.getGlobal(), rt, MO1.getOffset(), 0,
Indirect);
} else if (MO1.isSymbol())
emitExternalSymbolAddress(MO1.getSymbolName(), rt);
else if (MO1.isCPI())
emitConstPoolAddress(MO1.getIndex(), rt);
else if (MO1.isJTI())
emitJumpTableAddress(MO1.getIndex(), 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(),
X86II::getSizeOfImm(Desc->TSFlags));
break;
}
case X86II::MRMDestMem: {
MCE.emitByte(BaseOpcode);
emitMemModRMByte(MI, CurOp,
getX86RegNum(MI.getOperand(CurOp + X86::AddrNumOperands)
.getReg()));
CurOp += X86::AddrNumOperands + 1;
if (CurOp != NumOps)
emitConstant(MI.getOperand(CurOp++).getImm(),
X86II::getSizeOfImm(Desc->TSFlags));
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(),
X86II::getSizeOfImm(Desc->TSFlags));
break;
case X86II::MRMSrcMem: {
int AddrOperands = X86::AddrNumOperands;
intptr_t PCAdj = (CurOp + AddrOperands + 1 != NumOps) ?
X86II::getSizeOfImm(Desc->TSFlags) : 0;
MCE.emitByte(BaseOpcode);
emitMemModRMByte(MI, CurOp+1, getX86RegNum(MI.getOperand(CurOp).getReg()),
PCAdj);
CurOp += AddrOperands + 1;
if (CurOp != NumOps)
emitConstant(MI.getOperand(CurOp++).getImm(),
X86II::getSizeOfImm(Desc->TSFlags));
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)
break;
const MachineOperand &MO1 = MI.getOperand(CurOp++);
unsigned Size = X86II::getSizeOfImm(Desc->TSFlags);
if (MO1.isImm()) {
emitConstant(MO1.getImm(), Size);
break;
}
unsigned rt = Is64BitMode ? X86::reloc_pcrel_word
: (IsPIC ? X86::reloc_picrel_word : X86::reloc_absolute_word);
if (Opcode == X86::MOV64ri32)
rt = X86::reloc_absolute_word_sext; // FIXME: add X86II flag?
if (MO1.isGlobal()) {
bool Indirect = gvNeedsNonLazyPtr(MO1, TM);
emitGlobalAddress(MO1.getGlobal(), rt, MO1.getOffset(), 0,
Indirect);
} else if (MO1.isSymbol())
emitExternalSymbolAddress(MO1.getSymbolName(), rt);
else if (MO1.isCPI())
emitConstPoolAddress(MO1.getIndex(), rt);
else if (MO1.isJTI())
emitJumpTableAddress(MO1.getIndex(), 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: {
intptr_t PCAdj = (CurOp + X86::AddrNumOperands != NumOps) ?
(MI.getOperand(CurOp+X86::AddrNumOperands).isImm() ?
X86II::getSizeOfImm(Desc->TSFlags) : 4) : 0;
MCE.emitByte(BaseOpcode);
emitMemModRMByte(MI, CurOp, (Desc->TSFlags & X86II::FormMask)-X86II::MRM0m,
PCAdj);
CurOp += X86::AddrNumOperands;
if (CurOp == NumOps)
break;
const MachineOperand &MO = MI.getOperand(CurOp++);
unsigned Size = X86II::getSizeOfImm(Desc->TSFlags);
if (MO.isImm()) {
emitConstant(MO.getImm(), Size);
break;
}
unsigned rt = Is64BitMode ? X86::reloc_pcrel_word
: (IsPIC ? X86::reloc_picrel_word : X86::reloc_absolute_word);
if (Opcode == X86::MOV64mi32)
rt = X86::reloc_absolute_word_sext; // FIXME: add X86II flag?
if (MO.isGlobal()) {
bool Indirect = gvNeedsNonLazyPtr(MO, TM);
emitGlobalAddress(MO.getGlobal(), rt, MO.getOffset(), 0,
Indirect);
} else if (MO.isSymbol())
emitExternalSymbolAddress(MO.getSymbolName(), rt);
else if (MO.isCPI())
emitConstPoolAddress(MO.getIndex(), rt);
else if (MO.isJTI())
emitJumpTableAddress(MO.getIndex(), 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;
case X86II::MRM_C1:
MCE.emitByte(BaseOpcode);
MCE.emitByte(0xC1);
break;
case X86II::MRM_C8:
MCE.emitByte(BaseOpcode);
MCE.emitByte(0xC8);
break;
case X86II::MRM_C9:
MCE.emitByte(BaseOpcode);
MCE.emitByte(0xC9);
break;
case X86II::MRM_E8:
MCE.emitByte(BaseOpcode);
MCE.emitByte(0xE8);
break;
case X86II::MRM_F0:
MCE.emitByte(BaseOpcode);
MCE.emitByte(0xF0);
break;
}
if (!Desc->isVariadic() && CurOp != NumOps) {
#ifndef NDEBUG
dbgs() << "Cannot encode all operands of: " << MI << "\n";
#endif
llvm_unreachable(0);
}
MCE.processDebugLoc(MI.getDebugLoc(), false);
}
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