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llvm-project/llvm/lib/Target/X86/AsmPrinter/X86MCInstLower.cpp

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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 "X86MCInstLower.h"
#include "X86AsmPrinter.h"
#include "X86COFFMachineModuleInfo.h"
#include "X86MCAsmInfo.h"
#include "llvm/Analysis/DebugInfo.h"
#include "llvm/CodeGen/MachineModuleInfoImpls.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCInst.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/Target/Mangler.h"
#include "llvm/Support/FormattedStream.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/Type.h"
using namespace llvm;
const X86Subtarget &X86MCInstLower::getSubtarget() const {
return AsmPrinter.getSubtarget();
}
MachineModuleInfoMachO &X86MCInstLower::getMachOMMI() const {
assert(getSubtarget().isTargetDarwin() &&"Can only get MachO info on darwin");
return AsmPrinter.MMI->getObjFileInfo<MachineModuleInfoMachO>();
}
MCSymbol *X86MCInstLower::GetPICBaseSymbol() const {
const TargetLowering *TLI = AsmPrinter.TM.getTargetLowering();
return static_cast<const X86TargetLowering*>(TLI)->
getPICBaseSymbol(AsmPrinter.MF, Ctx);
}
/// GetSymbolFromOperand - Lower an MO_GlobalAddress or MO_ExternalSymbol
/// operand to an MCSymbol.
MCSymbol *X86MCInstLower::
GetSymbolFromOperand(const MachineOperand &MO) const {
assert((MO.isGlobal() || MO.isSymbol()) && "Isn't a symbol reference");
SmallString<128> Name;
if (!MO.isGlobal()) {
assert(MO.isSymbol());
Name += AsmPrinter.MAI->getGlobalPrefix();
Name += MO.getSymbolName();
} else {
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);
}
// 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 += "$non_lazy_ptr";
MCSymbol *Sym = Ctx.GetOrCreateSymbol(Name.str());
MachineModuleInfoImpl::StubValueTy &StubSym =
getMachOMMI().getGVStubEntry(Sym);
if (StubSym.getPointer() == 0) {
assert(MO.isGlobal() && "Extern symbol not handled yet");
StubSym =
MachineModuleInfoImpl::
StubValueTy(AsmPrinter.Mang->getSymbol(MO.getGlobal()),
!MO.getGlobal()->hasInternalLinkage());
}
return Sym;
}
case X86II::MO_DARWIN_HIDDEN_NONLAZY_PIC_BASE: {
Name += "$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(AsmPrinter.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(AsmPrinter.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_TLSGD: RefKind = MCSymbolRefExpr::VK_TLSGD; 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_NTPOFF: RefKind = MCSymbolRefExpr::VK_NTPOFF; 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(GetPICBaseSymbol(), Ctx),
Ctx);
if (MO.isJTI() && AsmPrinter.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.getOffset())
Expr = MCBinaryExpr::CreateAdd(Expr,
MCConstantExpr::Create(MO.getOffset(), Ctx),
Ctx);
return MCOperand::CreateExpr(Expr);
}
static void lower_subreg32(MCInst *MI, unsigned OpNo) {
// Convert registers in the addr mode according to subreg32.
unsigned Reg = MI->getOperand(OpNo).getReg();
if (Reg != 0)
MI->getOperand(OpNo).setReg(getX86SubSuperRegister(Reg, MVT::i32));
}
static void lower_lea64_32mem(MCInst *MI, unsigned OpNo) {
// Convert registers in the addr mode according to subreg64.
for (unsigned i = 0; i != 4; ++i) {
if (!MI->getOperand(OpNo+i).isReg()) continue;
unsigned Reg = MI->getOperand(OpNo+i).getReg();
if (Reg == 0) continue;
MI->getOperand(OpNo+i).setReg(getX86SubSuperRegister(Reg, MVT::i64));
}
}
/// LowerSubReg32_Op0 - Things like MOVZX16rr8 -> MOVZX32rr8.
static void LowerSubReg32_Op0(MCInst &OutMI, unsigned NewOpc) {
OutMI.setOpcode(NewOpc);
lower_subreg32(&OutMI, 0);
}
/// 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));
}
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:
MCOp = MCOperand::CreateExpr(MCSymbolRefExpr::Create(
MO.getMBB()->getSymbol(), Ctx));
break;
case MachineOperand::MO_GlobalAddress:
MCOp = LowerSymbolOperand(MO, GetSymbolFromOperand(MO));
break;
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;
}
OutMI.addOperand(MCOp);
}
// Handle a few special cases to eliminate operand modifiers.
switch (OutMI.getOpcode()) {
case X86::LEA64_32r: // Handle 'subreg rewriting' for the lea64_32mem operand.
lower_lea64_32mem(&OutMI, 1);
break;
case X86::MOVZX16rr8: LowerSubReg32_Op0(OutMI, X86::MOVZX32rr8); break;
case X86::MOVZX16rm8: LowerSubReg32_Op0(OutMI, X86::MOVZX32rm8); break;
case X86::MOVSX16rr8: LowerSubReg32_Op0(OutMI, X86::MOVSX32rr8); break;
case X86::MOVSX16rm8: LowerSubReg32_Op0(OutMI, X86::MOVSX32rm8); break;
case X86::MOVZX64rr32: LowerSubReg32_Op0(OutMI, X86::MOV32rr); break;
case X86::MOVZX64rm32: LowerSubReg32_Op0(OutMI, X86::MOV32rm); break;
case X86::MOV64ri64i32: LowerSubReg32_Op0(OutMI, X86::MOV32ri); break;
case X86::MOVZX64rr8: LowerSubReg32_Op0(OutMI, X86::MOVZX32rr8); break;
case X86::MOVZX64rm8: LowerSubReg32_Op0(OutMI, X86::MOVZX32rm8); break;
case X86::MOVZX64rr16: LowerSubReg32_Op0(OutMI, X86::MOVZX32rr16); break;
case X86::MOVZX64rm16: LowerSubReg32_Op0(OutMI, X86::MOVZX32rm16); break;
case X86::SETB_C8r: LowerUnaryToTwoAddr(OutMI, X86::SBB8rr); break;
case X86::SETB_C16r: LowerUnaryToTwoAddr(OutMI, X86::SBB16rr); break;
case X86::SETB_C32r: LowerUnaryToTwoAddr(OutMI, X86::SBB32rr); break;
case X86::SETB_C64r: LowerUnaryToTwoAddr(OutMI, X86::SBB64rr); break;
case X86::MOV8r0: LowerUnaryToTwoAddr(OutMI, X86::XOR8rr); break;
case X86::MOV32r0: LowerUnaryToTwoAddr(OutMI, X86::XOR32rr); break;
case X86::MMX_V_SET0: LowerUnaryToTwoAddr(OutMI, X86::MMX_PXORrr); break;
case X86::MMX_V_SETALLONES:
LowerUnaryToTwoAddr(OutMI, X86::MMX_PCMPEQDrr); break;
case X86::FsFLD0SS: LowerUnaryToTwoAddr(OutMI, X86::PXORrr); break;
case X86::FsFLD0SD: LowerUnaryToTwoAddr(OutMI, X86::PXORrr); break;
case X86::V_SET0PS: LowerUnaryToTwoAddr(OutMI, X86::XORPSrr); break;
case X86::V_SET0PD: LowerUnaryToTwoAddr(OutMI, X86::XORPDrr); break;
case X86::V_SET0PI: LowerUnaryToTwoAddr(OutMI, X86::PXORrr); break;
case X86::V_SETALLONES: LowerUnaryToTwoAddr(OutMI, X86::PCMPEQDrr); break;
case X86::MOV16r0:
LowerSubReg32_Op0(OutMI, X86::MOV32r0); // MOV16r0 -> MOV32r0
LowerUnaryToTwoAddr(OutMI, X86::XOR32rr); // MOV32r0 -> XOR32rr
break;
case X86::MOV64r0:
LowerSubReg32_Op0(OutMI, X86::MOV32r0); // MOV64r0 -> MOV32r0
LowerUnaryToTwoAddr(OutMI, X86::XOR32rr); // MOV32r0 -> XOR32rr
break;
// 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;
}
}
void X86AsmPrinter::PrintDebugValueComment(const MachineInstr *MI,
raw_ostream &O) {
// Only the target-dependent form of DBG_VALUE should get here.
// Referencing the offset and metadata as NOps-2 and NOps-1 is
// probably portable to other targets; frame pointer location is not.
unsigned NOps = MI->getNumOperands();
assert(NOps==7);
O << '\t' << MAI->getCommentString() << "DEBUG_VALUE: ";
// cast away const; DIetc do not take const operands for some reason.
DIVariable V(const_cast<MDNode *>(MI->getOperand(NOps-1).getMetadata()));
O << V.getName();
O << " <- ";
// Frame address. Currently handles register +- offset only.
assert(MI->getOperand(0).isReg() && MI->getOperand(3).isImm());
O << '['; printOperand(MI, 0, O); O << '+'; printOperand(MI, 3, O);
O << ']';
O << "+";
printOperand(MI, NOps-2, O);
}
void X86AsmPrinter::EmitInstruction(const MachineInstr *MI) {
X86MCInstLower MCInstLowering(OutContext, Mang, *this);
switch (MI->getOpcode()) {
case TargetOpcode::DBG_VALUE:
if (isVerbose() && OutStreamer.hasRawTextSupport()) {
std::string TmpStr;
raw_string_ostream OS(TmpStr);
PrintDebugValueComment(MI, OS);
OutStreamer.EmitRawText(StringRef(OS.str()));
}
return;
case X86::MOVPC32r: {
MCInst TmpInst;
// 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 = MCInstLowering.GetPICBaseSymbol();
TmpInst.setOpcode(X86::CALLpcrel32);
// FIXME: We would like an efficient form for this, so we don't have to do a
// lot of extra uniquing.
TmpInst.addOperand(MCOperand::CreateExpr(MCSymbolRefExpr::Create(PICBase,
OutContext)));
OutStreamer.EmitInstruction(TmpInst);
// Emit the label.
OutStreamer.EmitLabel(PICBase);
// popl $reg
TmpInst.setOpcode(X86::POP32r);
TmpInst.getOperand(0) = MCOperand::CreateReg(MI->getOperand(0).getReg());
OutStreamer.EmitInstruction(TmpInst);
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(MCInstLowering.GetPICBaseSymbol(), OutContext);
DotExpr = MCBinaryExpr::CreateSub(DotExpr, PICBase, OutContext);
DotExpr = MCBinaryExpr::CreateAdd(MCSymbolRefExpr::Create(OpSym,OutContext),
DotExpr, OutContext);
MCInst TmpInst;
TmpInst.setOpcode(X86::ADD32ri);
TmpInst.addOperand(MCOperand::CreateReg(MI->getOperand(0).getReg()));
TmpInst.addOperand(MCOperand::CreateReg(MI->getOperand(1).getReg()));
TmpInst.addOperand(MCOperand::CreateExpr(DotExpr));
OutStreamer.EmitInstruction(TmpInst);
return;
}
}
MCInst TmpInst;
MCInstLowering.Lower(MI, TmpInst);
OutStreamer.EmitInstruction(TmpInst);
}
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