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llvm-mirror/lib/Target/X86/X86MCInstLower.cpp
Benjamin Kramer 95a2f42a75 X86: Shrink certain forms of movsx. 
In particular:
movsbw %al, %ax   --> cbtw
movswl %ax, %eax  --> cwtl
movslq %eax, %rax --> cltq

According to Intel's manual those have the same performance characteristics but
come with a smaller encoding.

llvm-svn: 186174
2013-07-12 18:06:44 +00:00

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30 KiB
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//===-- X86MCInstLower.cpp - Convert X86 MachineInstr to an MCInst --------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains code to lower X86 MachineInstrs to their corresponding
// MCInst records.
//
//===----------------------------------------------------------------------===//
#include "X86AsmPrinter.h"
#include "InstPrinter/X86ATTInstPrinter.h"
#include "X86COFFMachineModuleInfo.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/CodeGen/MachineModuleInfoImpls.h"
#include "llvm/IR/Type.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCInst.h"
#include "llvm/MC/MCInstBuilder.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/Support/FormattedStream.h"
#include "llvm/Target/Mangler.h"
using namespace llvm;
namespace {
/// X86MCInstLower - This class is used to lower an MachineInstr into an MCInst.
class X86MCInstLower {
MCContext &Ctx;
Mangler *Mang;
const MachineFunction &MF;
const TargetMachine &TM;
const MCAsmInfo &MAI;
X86AsmPrinter &AsmPrinter;
public:
X86MCInstLower(Mangler *mang, const MachineFunction &MF,
X86AsmPrinter &asmprinter);
void Lower(const MachineInstr *MI, MCInst &OutMI) const;
MCSymbol *GetSymbolFromOperand(const MachineOperand &MO) const;
MCOperand LowerSymbolOperand(const MachineOperand &MO, MCSymbol *Sym) const;
private:
MachineModuleInfoMachO &getMachOMMI() const;
};
} // end anonymous namespace
X86MCInstLower::X86MCInstLower(Mangler *mang, const MachineFunction &mf,
X86AsmPrinter &asmprinter)
: Ctx(mf.getContext()), Mang(mang), MF(mf), TM(mf.getTarget()),
MAI(*TM.getMCAsmInfo()), AsmPrinter(asmprinter) {}
MachineModuleInfoMachO &X86MCInstLower::getMachOMMI() const {
return MF.getMMI().getObjFileInfo<MachineModuleInfoMachO>();
}
/// GetSymbolFromOperand - Lower an MO_GlobalAddress or MO_ExternalSymbol
/// operand to an MCSymbol.
MCSymbol *X86MCInstLower::
GetSymbolFromOperand(const MachineOperand &MO) const {
assert((MO.isGlobal() || MO.isSymbol() || MO.isMBB()) && "Isn't a symbol reference");
SmallString<128> Name;
if (MO.isGlobal()) {
const GlobalValue *GV = MO.getGlobal();
bool isImplicitlyPrivate = false;
if (MO.getTargetFlags() == X86II::MO_DARWIN_STUB ||
MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY ||
MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY_PIC_BASE ||
MO.getTargetFlags() == X86II::MO_DARWIN_HIDDEN_NONLAZY_PIC_BASE)
isImplicitlyPrivate = true;
Mang->getNameWithPrefix(Name, GV, isImplicitlyPrivate);
} else if (MO.isSymbol()) {
Name += MAI.getGlobalPrefix();
Name += MO.getSymbolName();
} else if (MO.isMBB()) {
Name += MO.getMBB()->getSymbol()->getName();
}
// If the target flags on the operand changes the name of the symbol, do that
// before we return the symbol.
switch (MO.getTargetFlags()) {
default: break;
case X86II::MO_DLLIMPORT: {
// Handle dllimport linkage.
const char *Prefix = "__imp_";
Name.insert(Name.begin(), Prefix, Prefix+strlen(Prefix));
break;
}
case X86II::MO_DARWIN_NONLAZY:
case X86II::MO_DARWIN_NONLAZY_PIC_BASE: {
Name += "$non_lazy_ptr";
MCSymbol *Sym = Ctx.GetOrCreateSymbol(Name.str());
MachineModuleInfoImpl::StubValueTy &StubSym =
getMachOMMI().getGVStubEntry(Sym);
if (StubSym.getPointer() == 0) {
assert(MO.isGlobal() && "Extern symbol not handled yet");
StubSym =
MachineModuleInfoImpl::
StubValueTy(Mang->getSymbol(MO.getGlobal()),
!MO.getGlobal()->hasInternalLinkage());
}
return Sym;
}
case X86II::MO_DARWIN_HIDDEN_NONLAZY_PIC_BASE: {
Name += "$non_lazy_ptr";
MCSymbol *Sym = Ctx.GetOrCreateSymbol(Name.str());
MachineModuleInfoImpl::StubValueTy &StubSym =
getMachOMMI().getHiddenGVStubEntry(Sym);
if (StubSym.getPointer() == 0) {
assert(MO.isGlobal() && "Extern symbol not handled yet");
StubSym =
MachineModuleInfoImpl::
StubValueTy(Mang->getSymbol(MO.getGlobal()),
!MO.getGlobal()->hasInternalLinkage());
}
return Sym;
}
case X86II::MO_DARWIN_STUB: {
Name += "$stub";
MCSymbol *Sym = Ctx.GetOrCreateSymbol(Name.str());
MachineModuleInfoImpl::StubValueTy &StubSym =
getMachOMMI().getFnStubEntry(Sym);
if (StubSym.getPointer())
return Sym;
if (MO.isGlobal()) {
StubSym =
MachineModuleInfoImpl::
StubValueTy(Mang->getSymbol(MO.getGlobal()),
!MO.getGlobal()->hasInternalLinkage());
} else {
Name.erase(Name.end()-5, Name.end());
StubSym =
MachineModuleInfoImpl::
StubValueTy(Ctx.GetOrCreateSymbol(Name.str()), false);
}
return Sym;
}
}
return Ctx.GetOrCreateSymbol(Name.str());
}
MCOperand X86MCInstLower::LowerSymbolOperand(const MachineOperand &MO,
MCSymbol *Sym) const {
// FIXME: We would like an efficient form for this, so we don't have to do a
// lot of extra uniquing.
const MCExpr *Expr = 0;
MCSymbolRefExpr::VariantKind RefKind = MCSymbolRefExpr::VK_None;
switch (MO.getTargetFlags()) {
default: llvm_unreachable("Unknown target flag on GV operand");
case X86II::MO_NO_FLAG: // No flag.
// These affect the name of the symbol, not any suffix.
case X86II::MO_DARWIN_NONLAZY:
case X86II::MO_DLLIMPORT:
case X86II::MO_DARWIN_STUB:
break;
case X86II::MO_TLVP: RefKind = MCSymbolRefExpr::VK_TLVP; break;
case X86II::MO_TLVP_PIC_BASE:
Expr = MCSymbolRefExpr::Create(Sym, MCSymbolRefExpr::VK_TLVP, Ctx);
// Subtract the pic base.
Expr = MCBinaryExpr::CreateSub(Expr,
MCSymbolRefExpr::Create(MF.getPICBaseSymbol(),
Ctx),
Ctx);
break;
case X86II::MO_SECREL: RefKind = MCSymbolRefExpr::VK_SECREL; break;
case X86II::MO_TLSGD: RefKind = MCSymbolRefExpr::VK_TLSGD; break;
case X86II::MO_TLSLD: RefKind = MCSymbolRefExpr::VK_TLSLD; break;
case X86II::MO_TLSLDM: RefKind = MCSymbolRefExpr::VK_TLSLDM; break;
case X86II::MO_GOTTPOFF: RefKind = MCSymbolRefExpr::VK_GOTTPOFF; break;
case X86II::MO_INDNTPOFF: RefKind = MCSymbolRefExpr::VK_INDNTPOFF; break;
case X86II::MO_TPOFF: RefKind = MCSymbolRefExpr::VK_TPOFF; break;
case X86II::MO_DTPOFF: RefKind = MCSymbolRefExpr::VK_DTPOFF; break;
case X86II::MO_NTPOFF: RefKind = MCSymbolRefExpr::VK_NTPOFF; break;
case X86II::MO_GOTNTPOFF: RefKind = MCSymbolRefExpr::VK_GOTNTPOFF; break;
case X86II::MO_GOTPCREL: RefKind = MCSymbolRefExpr::VK_GOTPCREL; break;
case X86II::MO_GOT: RefKind = MCSymbolRefExpr::VK_GOT; break;
case X86II::MO_GOTOFF: RefKind = MCSymbolRefExpr::VK_GOTOFF; break;
case X86II::MO_PLT: RefKind = MCSymbolRefExpr::VK_PLT; break;
case X86II::MO_PIC_BASE_OFFSET:
case X86II::MO_DARWIN_NONLAZY_PIC_BASE:
case X86II::MO_DARWIN_HIDDEN_NONLAZY_PIC_BASE:
Expr = MCSymbolRefExpr::Create(Sym, Ctx);
// Subtract the pic base.
Expr = MCBinaryExpr::CreateSub(Expr,
MCSymbolRefExpr::Create(MF.getPICBaseSymbol(), Ctx),
Ctx);
if (MO.isJTI() && MAI.hasSetDirective()) {
// If .set directive is supported, use it to reduce the number of
// relocations the assembler will generate for differences between
// local labels. This is only safe when the symbols are in the same
// section so we are restricting it to jumptable references.
MCSymbol *Label = Ctx.CreateTempSymbol();
AsmPrinter.OutStreamer.EmitAssignment(Label, Expr);
Expr = MCSymbolRefExpr::Create(Label, Ctx);
}
break;
}
if (Expr == 0)
Expr = MCSymbolRefExpr::Create(Sym, RefKind, Ctx);
if (!MO.isJTI() && !MO.isMBB() && MO.getOffset())
Expr = MCBinaryExpr::CreateAdd(Expr,
MCConstantExpr::Create(MO.getOffset(), Ctx),
Ctx);
return MCOperand::CreateExpr(Expr);
}
/// LowerUnaryToTwoAddr - R = setb -> R = sbb R, R
static void LowerUnaryToTwoAddr(MCInst &OutMI, unsigned NewOpc) {
OutMI.setOpcode(NewOpc);
OutMI.addOperand(OutMI.getOperand(0));
OutMI.addOperand(OutMI.getOperand(0));
}
/// \brief Simplify FOO $imm, %{al,ax,eax,rax} to FOO $imm, for instruction with
/// a short fixed-register form.
static void SimplifyShortImmForm(MCInst &Inst, unsigned Opcode) {
unsigned ImmOp = Inst.getNumOperands() - 1;
assert(Inst.getOperand(0).isReg() &&
(Inst.getOperand(ImmOp).isImm() || Inst.getOperand(ImmOp).isExpr()) &&
((Inst.getNumOperands() == 3 && Inst.getOperand(1).isReg() &&
Inst.getOperand(0).getReg() == Inst.getOperand(1).getReg()) ||
Inst.getNumOperands() == 2) && "Unexpected instruction!");
// Check whether the destination register can be fixed.
unsigned Reg = Inst.getOperand(0).getReg();
if (Reg != X86::AL && Reg != X86::AX && Reg != X86::EAX && Reg != X86::RAX)
return;
// If so, rewrite the instruction.
MCOperand Saved = Inst.getOperand(ImmOp);
Inst = MCInst();
Inst.setOpcode(Opcode);
Inst.addOperand(Saved);
}
/// \brief If a movsx instruction has a shorter encoding for the used register
/// simplify the instruction to use it instead.
static void SimplifyMOVSX(MCInst &Inst) {
unsigned NewOpcode = 0;
unsigned Op0 = Inst.getOperand(0).getReg(), Op1 = Inst.getOperand(1).getReg();
switch (Inst.getOpcode()) {
default:
llvm_unreachable("Unexpected instruction!");
case X86::MOVSX16rr8: // movsbw %al, %ax --> cbtw
if (Op0 == X86::AX && Op1 == X86::AL)
NewOpcode = X86::CBW;
break;
case X86::MOVSX32rr16: // movswl %ax, %eax --> cwtl
if (Op0 == X86::EAX && Op1 == X86::AX)
NewOpcode = X86::CWDE;
break;
case X86::MOVSX64rr32: // movslq %eax, %rax --> cltq
if (Op0 == X86::RAX && Op1 == X86::EAX)
NewOpcode = X86::CDQE;
break;
}
if (NewOpcode != 0) {
Inst = MCInst();
Inst.setOpcode(NewOpcode);
}
}
/// \brief Simplify things like MOV32rm to MOV32o32a.
static void SimplifyShortMoveForm(X86AsmPrinter &Printer, MCInst &Inst,
unsigned Opcode) {
// Don't make these simplifications in 64-bit mode; other assemblers don't
// perform them because they make the code larger.
if (Printer.getSubtarget().is64Bit())
return;
bool IsStore = Inst.getOperand(0).isReg() && Inst.getOperand(1).isReg();
unsigned AddrBase = IsStore;
unsigned RegOp = IsStore ? 0 : 5;
unsigned AddrOp = AddrBase + 3;
assert(Inst.getNumOperands() == 6 && Inst.getOperand(RegOp).isReg() &&
Inst.getOperand(AddrBase + 0).isReg() && // base
Inst.getOperand(AddrBase + 1).isImm() && // scale
Inst.getOperand(AddrBase + 2).isReg() && // index register
(Inst.getOperand(AddrOp).isExpr() || // address
Inst.getOperand(AddrOp).isImm())&&
Inst.getOperand(AddrBase + 4).isReg() && // segment
"Unexpected instruction!");
// Check whether the destination register can be fixed.
unsigned Reg = Inst.getOperand(RegOp).getReg();
if (Reg != X86::AL && Reg != X86::AX && Reg != X86::EAX && Reg != X86::RAX)
return;
// Check whether this is an absolute address.
// FIXME: We know TLVP symbol refs aren't, but there should be a better way
// to do this here.
bool Absolute = true;
if (Inst.getOperand(AddrOp).isExpr()) {
const MCExpr *MCE = Inst.getOperand(AddrOp).getExpr();
if (const MCSymbolRefExpr *SRE = dyn_cast<MCSymbolRefExpr>(MCE))
if (SRE->getKind() == MCSymbolRefExpr::VK_TLVP)
Absolute = false;
}
if (Absolute &&
(Inst.getOperand(AddrBase + 0).getReg() != 0 ||
Inst.getOperand(AddrBase + 2).getReg() != 0 ||
Inst.getOperand(AddrBase + 4).getReg() != 0 ||
Inst.getOperand(AddrBase + 1).getImm() != 1))
return;
// If so, rewrite the instruction.
MCOperand Saved = Inst.getOperand(AddrOp);
Inst = MCInst();
Inst.setOpcode(Opcode);
Inst.addOperand(Saved);
}
void X86MCInstLower::Lower(const MachineInstr *MI, MCInst &OutMI) const {
OutMI.setOpcode(MI->getOpcode());
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
const MachineOperand &MO = MI->getOperand(i);
MCOperand MCOp;
switch (MO.getType()) {
default:
MI->dump();
llvm_unreachable("unknown operand type");
case MachineOperand::MO_Register:
// Ignore all implicit register operands.
if (MO.isImplicit()) continue;
MCOp = MCOperand::CreateReg(MO.getReg());
break;
case MachineOperand::MO_Immediate:
MCOp = MCOperand::CreateImm(MO.getImm());
break;
case MachineOperand::MO_MachineBasicBlock:
case MachineOperand::MO_GlobalAddress:
case MachineOperand::MO_ExternalSymbol:
MCOp = LowerSymbolOperand(MO, GetSymbolFromOperand(MO));
break;
case MachineOperand::MO_JumpTableIndex:
MCOp = LowerSymbolOperand(MO, AsmPrinter.GetJTISymbol(MO.getIndex()));
break;
case MachineOperand::MO_ConstantPoolIndex:
MCOp = LowerSymbolOperand(MO, AsmPrinter.GetCPISymbol(MO.getIndex()));
break;
case MachineOperand::MO_BlockAddress:
MCOp = LowerSymbolOperand(MO,
AsmPrinter.GetBlockAddressSymbol(MO.getBlockAddress()));
break;
case MachineOperand::MO_RegisterMask:
// Ignore call clobbers.
continue;
}
OutMI.addOperand(MCOp);
}
// Handle a few special cases to eliminate operand modifiers.
ReSimplify:
switch (OutMI.getOpcode()) {
case X86::LEA64_32r:
case X86::LEA64r:
case X86::LEA16r:
case X86::LEA32r:
// LEA should have a segment register, but it must be empty.
assert(OutMI.getNumOperands() == 1+X86::AddrNumOperands &&
"Unexpected # of LEA operands");
assert(OutMI.getOperand(1+X86::AddrSegmentReg).getReg() == 0 &&
"LEA has segment specified!");
break;
case X86::MOV32r0: LowerUnaryToTwoAddr(OutMI, X86::XOR32rr); break;
case X86::MOV32ri64:
OutMI.setOpcode(X86::MOV32ri);
break;
// Commute operands to get a smaller encoding by using VEX.R instead of VEX.B
// if one of the registers is extended, but other isn't.
case X86::VMOVAPDrr:
case X86::VMOVAPDYrr:
case X86::VMOVAPSrr:
case X86::VMOVAPSYrr:
case X86::VMOVDQArr:
case X86::VMOVDQAYrr:
case X86::VMOVDQUrr:
case X86::VMOVDQUYrr:
case X86::VMOVUPDrr:
case X86::VMOVUPDYrr:
case X86::VMOVUPSrr:
case X86::VMOVUPSYrr: {
if (!X86II::isX86_64ExtendedReg(OutMI.getOperand(0).getReg()) &&
X86II::isX86_64ExtendedReg(OutMI.getOperand(1).getReg())) {
unsigned NewOpc;
switch (OutMI.getOpcode()) {
default: llvm_unreachable("Invalid opcode");
case X86::VMOVAPDrr: NewOpc = X86::VMOVAPDrr_REV; break;
case X86::VMOVAPDYrr: NewOpc = X86::VMOVAPDYrr_REV; break;
case X86::VMOVAPSrr: NewOpc = X86::VMOVAPSrr_REV; break;
case X86::VMOVAPSYrr: NewOpc = X86::VMOVAPSYrr_REV; break;
case X86::VMOVDQArr: NewOpc = X86::VMOVDQArr_REV; break;
case X86::VMOVDQAYrr: NewOpc = X86::VMOVDQAYrr_REV; break;
case X86::VMOVDQUrr: NewOpc = X86::VMOVDQUrr_REV; break;
case X86::VMOVDQUYrr: NewOpc = X86::VMOVDQUYrr_REV; break;
case X86::VMOVUPDrr: NewOpc = X86::VMOVUPDrr_REV; break;
case X86::VMOVUPDYrr: NewOpc = X86::VMOVUPDYrr_REV; break;
case X86::VMOVUPSrr: NewOpc = X86::VMOVUPSrr_REV; break;
case X86::VMOVUPSYrr: NewOpc = X86::VMOVUPSYrr_REV; break;
}
OutMI.setOpcode(NewOpc);
}
break;
}
case X86::VMOVSDrr:
case X86::VMOVSSrr: {
if (!X86II::isX86_64ExtendedReg(OutMI.getOperand(0).getReg()) &&
X86II::isX86_64ExtendedReg(OutMI.getOperand(2).getReg())) {
unsigned NewOpc;
switch (OutMI.getOpcode()) {
default: llvm_unreachable("Invalid opcode");
case X86::VMOVSDrr: NewOpc = X86::VMOVSDrr_REV; break;
case X86::VMOVSSrr: NewOpc = X86::VMOVSSrr_REV; break;
}
OutMI.setOpcode(NewOpc);
}
break;
}
// TAILJMPr64, CALL64r, CALL64pcrel32 - These instructions have register
// inputs modeled as normal uses instead of implicit uses. As such, truncate
// off all but the first operand (the callee). FIXME: Change isel.
case X86::TAILJMPr64:
case X86::CALL64r:
case X86::CALL64pcrel32: {
unsigned Opcode = OutMI.getOpcode();
MCOperand Saved = OutMI.getOperand(0);
OutMI = MCInst();
OutMI.setOpcode(Opcode);
OutMI.addOperand(Saved);
break;
}
case X86::EH_RETURN:
case X86::EH_RETURN64: {
OutMI = MCInst();
OutMI.setOpcode(X86::RET);
break;
}
// TAILJMPd, TAILJMPd64 - Lower to the correct jump instructions.
case X86::TAILJMPr:
case X86::TAILJMPd:
case X86::TAILJMPd64: {
unsigned Opcode;
switch (OutMI.getOpcode()) {
default: llvm_unreachable("Invalid opcode");
case X86::TAILJMPr: Opcode = X86::JMP32r; break;
case X86::TAILJMPd:
case X86::TAILJMPd64: Opcode = X86::JMP_1; break;
}
MCOperand Saved = OutMI.getOperand(0);
OutMI = MCInst();
OutMI.setOpcode(Opcode);
OutMI.addOperand(Saved);
break;
}
// These are pseudo-ops for OR to help with the OR->ADD transformation. We do
// this with an ugly goto in case the resultant OR uses EAX and needs the
// short form.
case X86::ADD16rr_DB: OutMI.setOpcode(X86::OR16rr); goto ReSimplify;
case X86::ADD32rr_DB: OutMI.setOpcode(X86::OR32rr); goto ReSimplify;
case X86::ADD64rr_DB: OutMI.setOpcode(X86::OR64rr); goto ReSimplify;
case X86::ADD16ri_DB: OutMI.setOpcode(X86::OR16ri); goto ReSimplify;
case X86::ADD32ri_DB: OutMI.setOpcode(X86::OR32ri); goto ReSimplify;
case X86::ADD64ri32_DB: OutMI.setOpcode(X86::OR64ri32); goto ReSimplify;
case X86::ADD16ri8_DB: OutMI.setOpcode(X86::OR16ri8); goto ReSimplify;
case X86::ADD32ri8_DB: OutMI.setOpcode(X86::OR32ri8); goto ReSimplify;
case X86::ADD64ri8_DB: OutMI.setOpcode(X86::OR64ri8); goto ReSimplify;
// The assembler backend wants to see branches in their small form and relax
// them to their large form. The JIT can only handle the large form because
// it does not do relaxation. For now, translate the large form to the
// small one here.
case X86::JMP_4: OutMI.setOpcode(X86::JMP_1); break;
case X86::JO_4: OutMI.setOpcode(X86::JO_1); break;
case X86::JNO_4: OutMI.setOpcode(X86::JNO_1); break;
case X86::JB_4: OutMI.setOpcode(X86::JB_1); break;
case X86::JAE_4: OutMI.setOpcode(X86::JAE_1); break;
case X86::JE_4: OutMI.setOpcode(X86::JE_1); break;
case X86::JNE_4: OutMI.setOpcode(X86::JNE_1); break;
case X86::JBE_4: OutMI.setOpcode(X86::JBE_1); break;
case X86::JA_4: OutMI.setOpcode(X86::JA_1); break;
case X86::JS_4: OutMI.setOpcode(X86::JS_1); break;
case X86::JNS_4: OutMI.setOpcode(X86::JNS_1); break;
case X86::JP_4: OutMI.setOpcode(X86::JP_1); break;
case X86::JNP_4: OutMI.setOpcode(X86::JNP_1); break;
case X86::JL_4: OutMI.setOpcode(X86::JL_1); break;
case X86::JGE_4: OutMI.setOpcode(X86::JGE_1); break;
case X86::JLE_4: OutMI.setOpcode(X86::JLE_1); break;
case X86::JG_4: OutMI.setOpcode(X86::JG_1); break;
// Atomic load and store require a separate pseudo-inst because Acquire
// implies mayStore and Release implies mayLoad; fix these to regular MOV
// instructions here
case X86::ACQUIRE_MOV8rm: OutMI.setOpcode(X86::MOV8rm); goto ReSimplify;
case X86::ACQUIRE_MOV16rm: OutMI.setOpcode(X86::MOV16rm); goto ReSimplify;
case X86::ACQUIRE_MOV32rm: OutMI.setOpcode(X86::MOV32rm); goto ReSimplify;
case X86::ACQUIRE_MOV64rm: OutMI.setOpcode(X86::MOV64rm); goto ReSimplify;
case X86::RELEASE_MOV8mr: OutMI.setOpcode(X86::MOV8mr); goto ReSimplify;
case X86::RELEASE_MOV16mr: OutMI.setOpcode(X86::MOV16mr); goto ReSimplify;
case X86::RELEASE_MOV32mr: OutMI.setOpcode(X86::MOV32mr); goto ReSimplify;
case X86::RELEASE_MOV64mr: OutMI.setOpcode(X86::MOV64mr); goto ReSimplify;
// We don't currently select the correct instruction form for instructions
// which have a short %eax, etc. form. Handle this by custom lowering, for
// now.
//
// Note, we are currently not handling the following instructions:
// MOV64ao8, MOV64o8a
// XCHG16ar, XCHG32ar, XCHG64ar
case X86::MOV8mr_NOREX:
case X86::MOV8mr: SimplifyShortMoveForm(AsmPrinter, OutMI, X86::MOV8ao8); break;
case X86::MOV8rm_NOREX:
case X86::MOV8rm: SimplifyShortMoveForm(AsmPrinter, OutMI, X86::MOV8o8a); break;
case X86::MOV16mr: SimplifyShortMoveForm(AsmPrinter, OutMI, X86::MOV16ao16); break;
case X86::MOV16rm: SimplifyShortMoveForm(AsmPrinter, OutMI, X86::MOV16o16a); break;
case X86::MOV32mr: SimplifyShortMoveForm(AsmPrinter, OutMI, X86::MOV32ao32); break;
case X86::MOV32rm: SimplifyShortMoveForm(AsmPrinter, OutMI, X86::MOV32o32a); break;
case X86::ADC8ri: SimplifyShortImmForm(OutMI, X86::ADC8i8); break;
case X86::ADC16ri: SimplifyShortImmForm(OutMI, X86::ADC16i16); break;
case X86::ADC32ri: SimplifyShortImmForm(OutMI, X86::ADC32i32); break;
case X86::ADC64ri32: SimplifyShortImmForm(OutMI, X86::ADC64i32); break;
case X86::ADD8ri: SimplifyShortImmForm(OutMI, X86::ADD8i8); break;
case X86::ADD16ri: SimplifyShortImmForm(OutMI, X86::ADD16i16); break;
case X86::ADD32ri: SimplifyShortImmForm(OutMI, X86::ADD32i32); break;
case X86::ADD64ri32: SimplifyShortImmForm(OutMI, X86::ADD64i32); break;
case X86::AND8ri: SimplifyShortImmForm(OutMI, X86::AND8i8); break;
case X86::AND16ri: SimplifyShortImmForm(OutMI, X86::AND16i16); break;
case X86::AND32ri: SimplifyShortImmForm(OutMI, X86::AND32i32); break;
case X86::AND64ri32: SimplifyShortImmForm(OutMI, X86::AND64i32); break;
case X86::CMP8ri: SimplifyShortImmForm(OutMI, X86::CMP8i8); break;
case X86::CMP16ri: SimplifyShortImmForm(OutMI, X86::CMP16i16); break;
case X86::CMP32ri: SimplifyShortImmForm(OutMI, X86::CMP32i32); break;
case X86::CMP64ri32: SimplifyShortImmForm(OutMI, X86::CMP64i32); break;
case X86::OR8ri: SimplifyShortImmForm(OutMI, X86::OR8i8); break;
case X86::OR16ri: SimplifyShortImmForm(OutMI, X86::OR16i16); break;
case X86::OR32ri: SimplifyShortImmForm(OutMI, X86::OR32i32); break;
case X86::OR64ri32: SimplifyShortImmForm(OutMI, X86::OR64i32); break;
case X86::SBB8ri: SimplifyShortImmForm(OutMI, X86::SBB8i8); break;
case X86::SBB16ri: SimplifyShortImmForm(OutMI, X86::SBB16i16); break;
case X86::SBB32ri: SimplifyShortImmForm(OutMI, X86::SBB32i32); break;
case X86::SBB64ri32: SimplifyShortImmForm(OutMI, X86::SBB64i32); break;
case X86::SUB8ri: SimplifyShortImmForm(OutMI, X86::SUB8i8); break;
case X86::SUB16ri: SimplifyShortImmForm(OutMI, X86::SUB16i16); break;
case X86::SUB32ri: SimplifyShortImmForm(OutMI, X86::SUB32i32); break;
case X86::SUB64ri32: SimplifyShortImmForm(OutMI, X86::SUB64i32); break;
case X86::TEST8ri: SimplifyShortImmForm(OutMI, X86::TEST8i8); break;
case X86::TEST16ri: SimplifyShortImmForm(OutMI, X86::TEST16i16); break;
case X86::TEST32ri: SimplifyShortImmForm(OutMI, X86::TEST32i32); break;
case X86::TEST64ri32: SimplifyShortImmForm(OutMI, X86::TEST64i32); break;
case X86::XOR8ri: SimplifyShortImmForm(OutMI, X86::XOR8i8); break;
case X86::XOR16ri: SimplifyShortImmForm(OutMI, X86::XOR16i16); break;
case X86::XOR32ri: SimplifyShortImmForm(OutMI, X86::XOR32i32); break;
case X86::XOR64ri32: SimplifyShortImmForm(OutMI, X86::XOR64i32); break;
// Try to shrink some forms of movsx.
case X86::MOVSX16rr8:
case X86::MOVSX32rr16:
case X86::MOVSX64rr32:
SimplifyMOVSX(OutMI);
break;
case X86::MORESTACK_RET:
OutMI.setOpcode(X86::RET);
break;
case X86::MORESTACK_RET_RESTORE_R10:
OutMI.setOpcode(X86::MOV64rr);
OutMI.addOperand(MCOperand::CreateReg(X86::R10));
OutMI.addOperand(MCOperand::CreateReg(X86::RAX));
AsmPrinter.OutStreamer.EmitInstruction(MCInstBuilder(X86::RET));
break;
}
}
static void LowerTlsAddr(MCStreamer &OutStreamer,
X86MCInstLower &MCInstLowering,
const MachineInstr &MI) {
bool is64Bits = MI.getOpcode() == X86::TLS_addr64 ||
MI.getOpcode() == X86::TLS_base_addr64;
bool needsPadding = MI.getOpcode() == X86::TLS_addr64;
MCContext &context = OutStreamer.getContext();
if (needsPadding)
OutStreamer.EmitInstruction(MCInstBuilder(X86::DATA16_PREFIX));
MCSymbolRefExpr::VariantKind SRVK;
switch (MI.getOpcode()) {
case X86::TLS_addr32:
case X86::TLS_addr64:
SRVK = MCSymbolRefExpr::VK_TLSGD;
break;
case X86::TLS_base_addr32:
SRVK = MCSymbolRefExpr::VK_TLSLDM;
break;
case X86::TLS_base_addr64:
SRVK = MCSymbolRefExpr::VK_TLSLD;
break;
default:
llvm_unreachable("unexpected opcode");
}
MCSymbol *sym = MCInstLowering.GetSymbolFromOperand(MI.getOperand(3));
const MCSymbolRefExpr *symRef = MCSymbolRefExpr::Create(sym, SRVK, context);
MCInst LEA;
if (is64Bits) {
LEA.setOpcode(X86::LEA64r);
LEA.addOperand(MCOperand::CreateReg(X86::RDI)); // dest
LEA.addOperand(MCOperand::CreateReg(X86::RIP)); // base
LEA.addOperand(MCOperand::CreateImm(1)); // scale
LEA.addOperand(MCOperand::CreateReg(0)); // index
LEA.addOperand(MCOperand::CreateExpr(symRef)); // disp
LEA.addOperand(MCOperand::CreateReg(0)); // seg
} else if (SRVK == MCSymbolRefExpr::VK_TLSLDM) {
LEA.setOpcode(X86::LEA32r);
LEA.addOperand(MCOperand::CreateReg(X86::EAX)); // dest
LEA.addOperand(MCOperand::CreateReg(X86::EBX)); // base
LEA.addOperand(MCOperand::CreateImm(1)); // scale
LEA.addOperand(MCOperand::CreateReg(0)); // index
LEA.addOperand(MCOperand::CreateExpr(symRef)); // disp
LEA.addOperand(MCOperand::CreateReg(0)); // seg
} else {
LEA.setOpcode(X86::LEA32r);
LEA.addOperand(MCOperand::CreateReg(X86::EAX)); // dest
LEA.addOperand(MCOperand::CreateReg(0)); // base
LEA.addOperand(MCOperand::CreateImm(1)); // scale
LEA.addOperand(MCOperand::CreateReg(X86::EBX)); // index
LEA.addOperand(MCOperand::CreateExpr(symRef)); // disp
LEA.addOperand(MCOperand::CreateReg(0)); // seg
}
OutStreamer.EmitInstruction(LEA);
if (needsPadding) {
OutStreamer.EmitInstruction(MCInstBuilder(X86::DATA16_PREFIX));
OutStreamer.EmitInstruction(MCInstBuilder(X86::DATA16_PREFIX));
OutStreamer.EmitInstruction(MCInstBuilder(X86::REX64_PREFIX));
}
StringRef name = is64Bits ? "__tls_get_addr" : "___tls_get_addr";
MCSymbol *tlsGetAddr = context.GetOrCreateSymbol(name);
const MCSymbolRefExpr *tlsRef =
MCSymbolRefExpr::Create(tlsGetAddr,
MCSymbolRefExpr::VK_PLT,
context);
OutStreamer.EmitInstruction(MCInstBuilder(is64Bits ? X86::CALL64pcrel32
: X86::CALLpcrel32)
.addExpr(tlsRef));
}
void X86AsmPrinter::EmitInstruction(const MachineInstr *MI) {
X86MCInstLower MCInstLowering(Mang, *MF, *this);
switch (MI->getOpcode()) {
case TargetOpcode::DBG_VALUE:
llvm_unreachable("Should be handled target independently");
// Emit nothing here but a comment if we can.
case X86::Int_MemBarrier:
if (OutStreamer.hasRawTextSupport())
OutStreamer.EmitRawText(StringRef("\t#MEMBARRIER"));
return;
case X86::EH_RETURN:
case X86::EH_RETURN64: {
// Lower these as normal, but add some comments.
unsigned Reg = MI->getOperand(0).getReg();
OutStreamer.AddComment(StringRef("eh_return, addr: %") +
X86ATTInstPrinter::getRegisterName(Reg));
break;
}
case X86::TAILJMPr:
case X86::TAILJMPd:
case X86::TAILJMPd64:
// Lower these as normal, but add some comments.
OutStreamer.AddComment("TAILCALL");
break;
case X86::TLS_addr32:
case X86::TLS_addr64:
case X86::TLS_base_addr32:
case X86::TLS_base_addr64:
return LowerTlsAddr(OutStreamer, MCInstLowering, *MI);
case X86::MOVPC32r: {
// This is a pseudo op for a two instruction sequence with a label, which
// looks like:
// call "L1$pb"
// "L1$pb":
// popl %esi
// Emit the call.
MCSymbol *PICBase = MF->getPICBaseSymbol();
// FIXME: We would like an efficient form for this, so we don't have to do a
// lot of extra uniquing.
OutStreamer.EmitInstruction(MCInstBuilder(X86::CALLpcrel32)
.addExpr(MCSymbolRefExpr::Create(PICBase, OutContext)));
// Emit the label.
OutStreamer.EmitLabel(PICBase);
// popl $reg
OutStreamer.EmitInstruction(MCInstBuilder(X86::POP32r)
.addReg(MI->getOperand(0).getReg()));
return;
}
case X86::ADD32ri: {
// Lower the MO_GOT_ABSOLUTE_ADDRESS form of ADD32ri.
if (MI->getOperand(2).getTargetFlags() != X86II::MO_GOT_ABSOLUTE_ADDRESS)
break;
// Okay, we have something like:
// EAX = ADD32ri EAX, MO_GOT_ABSOLUTE_ADDRESS(@MYGLOBAL)
// For this, we want to print something like:
// MYGLOBAL + (. - PICBASE)
// However, we can't generate a ".", so just emit a new label here and refer
// to it.
MCSymbol *DotSym = OutContext.CreateTempSymbol();
OutStreamer.EmitLabel(DotSym);
// Now that we have emitted the label, lower the complex operand expression.
MCSymbol *OpSym = MCInstLowering.GetSymbolFromOperand(MI->getOperand(2));
const MCExpr *DotExpr = MCSymbolRefExpr::Create(DotSym, OutContext);
const MCExpr *PICBase =
MCSymbolRefExpr::Create(MF->getPICBaseSymbol(), OutContext);
DotExpr = MCBinaryExpr::CreateSub(DotExpr, PICBase, OutContext);
DotExpr = MCBinaryExpr::CreateAdd(MCSymbolRefExpr::Create(OpSym,OutContext),
DotExpr, OutContext);
OutStreamer.EmitInstruction(MCInstBuilder(X86::ADD32ri)
.addReg(MI->getOperand(0).getReg())
.addReg(MI->getOperand(1).getReg())
.addExpr(DotExpr));
return;
}
}
MCInst TmpInst;
MCInstLowering.Lower(MI, TmpInst);
OutStreamer.EmitInstruction(TmpInst);
}
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