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//==-- AArch64MCInstLower.cpp - Convert AArch64 MachineInstr to an MCInst --==//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file contains code to lower AArch64 MachineInstrs to their corresponding
// MCInst records.
//
//===----------------------------------------------------------------------===//
#include "AArch64MCInstLower.h"
#include "MCTargetDesc/AArch64MCExpr.h"
#include "Utils/AArch64BaseInfo.h"
#include "llvm/CodeGen/AsmPrinter.h"
#include "llvm/CodeGen/MachineBasicBlock.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/MachineModuleInfoImpls.h"
#include "llvm/IR/Mangler.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCInst.h"
#include "llvm/Support/CodeGen.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Target/TargetLoweringObjectFile.h"
#include "llvm/Target/TargetMachine.h"
using namespace llvm;
extern cl::opt<bool> EnableAArch64ELFLocalDynamicTLSGeneration;
AArch64MCInstLower::AArch64MCInstLower(MCContext &ctx, AsmPrinter &printer)
: Ctx(ctx), Printer(printer) {}
MCSymbol *
AArch64MCInstLower::GetGlobalAddressSymbol(const MachineOperand &MO) const {
const GlobalValue *GV = MO.getGlobal();
unsigned TargetFlags = MO.getTargetFlags();
const Triple &TheTriple = Printer.TM.getTargetTriple();
if (!TheTriple.isOSBinFormatCOFF())
return Printer.getSymbolPreferLocal(*GV);
assert(TheTriple.isOSWindows() &&
"Windows is the only supported COFF target");
bool IsIndirect = (TargetFlags & (AArch64II::MO_DLLIMPORT | AArch64II::MO_COFFSTUB));
if (!IsIndirect)
return Printer.getSymbol(GV);
SmallString<128> Name;
if (TargetFlags & AArch64II::MO_DLLIMPORT)
Name = "__imp_";
else if (TargetFlags & AArch64II::MO_COFFSTUB)
Name = ".refptr.";
Printer.TM.getNameWithPrefix(Name, GV,
Printer.getObjFileLowering().getMangler());
MCSymbol *MCSym = Ctx.getOrCreateSymbol(Name);
if (TargetFlags & AArch64II::MO_COFFSTUB) {
MachineModuleInfoCOFF &MMICOFF =
Printer.MMI->getObjFileInfo<MachineModuleInfoCOFF>();
MachineModuleInfoImpl::StubValueTy &StubSym =
MMICOFF.getGVStubEntry(MCSym);
if (!StubSym.getPointer())
StubSym = MachineModuleInfoImpl::StubValueTy(Printer.getSymbol(GV), true);
}
return MCSym;
}
MCSymbol *
AArch64MCInstLower::GetExternalSymbolSymbol(const MachineOperand &MO) const {
return Printer.GetExternalSymbolSymbol(MO.getSymbolName());
}
MCOperand AArch64MCInstLower::lowerSymbolOperandDarwin(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.
MCSymbolRefExpr::VariantKind RefKind = MCSymbolRefExpr::VK_None;
if ((MO.getTargetFlags() & AArch64II::MO_GOT) != 0) {
if ((MO.getTargetFlags() & AArch64II::MO_FRAGMENT) == AArch64II::MO_PAGE)
RefKind = MCSymbolRefExpr::VK_GOTPAGE;
else if ((MO.getTargetFlags() & AArch64II::MO_FRAGMENT) ==
AArch64II::MO_PAGEOFF)
RefKind = MCSymbolRefExpr::VK_GOTPAGEOFF;
else
llvm_unreachable("Unexpected target flags with MO_GOT on GV operand");
} else if ((MO.getTargetFlags() & AArch64II::MO_TLS) != 0) {
if ((MO.getTargetFlags() & AArch64II::MO_FRAGMENT) == AArch64II::MO_PAGE)
RefKind = MCSymbolRefExpr::VK_TLVPPAGE;
else if ((MO.getTargetFlags() & AArch64II::MO_FRAGMENT) ==
AArch64II::MO_PAGEOFF)
RefKind = MCSymbolRefExpr::VK_TLVPPAGEOFF;
else
llvm_unreachable("Unexpected target flags with MO_TLS on GV operand");
} else {
if ((MO.getTargetFlags() & AArch64II::MO_FRAGMENT) == AArch64II::MO_PAGE)
RefKind = MCSymbolRefExpr::VK_PAGE;
else if ((MO.getTargetFlags() & AArch64II::MO_FRAGMENT) ==
AArch64II::MO_PAGEOFF)
RefKind = MCSymbolRefExpr::VK_PAGEOFF;
}
const MCExpr *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);
}
MCOperand AArch64MCInstLower::lowerSymbolOperandELF(const MachineOperand &MO,
MCSymbol *Sym) const {
uint32_t RefFlags = 0;
if (MO.getTargetFlags() & AArch64II::MO_GOT)
RefFlags |= AArch64MCExpr::VK_GOT;
else if (MO.getTargetFlags() & AArch64II::MO_TLS) {
TLSModel::Model Model;
if (MO.isGlobal()) {
const GlobalValue *GV = MO.getGlobal();
Model = Printer.TM.getTLSModel(GV);
if (!EnableAArch64ELFLocalDynamicTLSGeneration &&
Model == TLSModel::LocalDynamic)
Model = TLSModel::GeneralDynamic;
} else {
assert(MO.isSymbol() &&
StringRef(MO.getSymbolName()) == "_TLS_MODULE_BASE_" &&
"unexpected external TLS symbol");
// The general dynamic access sequence is used to get the
// address of _TLS_MODULE_BASE_.
Model = TLSModel::GeneralDynamic;
}
switch (Model) {
case TLSModel::InitialExec:
RefFlags |= AArch64MCExpr::VK_GOTTPREL;
break;
case TLSModel::LocalExec:
RefFlags |= AArch64MCExpr::VK_TPREL;
break;
case TLSModel::LocalDynamic:
RefFlags |= AArch64MCExpr::VK_DTPREL;
break;
case TLSModel::GeneralDynamic:
RefFlags |= AArch64MCExpr::VK_TLSDESC;
break;
}
} else if (MO.getTargetFlags() & AArch64II::MO_PREL) {
RefFlags |= AArch64MCExpr::VK_PREL;
} else {
// No modifier means this is a generic reference, classified as absolute for
// the cases where it matters (:abs_g0: etc).
RefFlags |= AArch64MCExpr::VK_ABS;
}
if ((MO.getTargetFlags() & AArch64II::MO_FRAGMENT) == AArch64II::MO_PAGE)
RefFlags |= AArch64MCExpr::VK_PAGE;
else if ((MO.getTargetFlags() & AArch64II::MO_FRAGMENT) ==
AArch64II::MO_PAGEOFF)
RefFlags |= AArch64MCExpr::VK_PAGEOFF;
else if ((MO.getTargetFlags() & AArch64II::MO_FRAGMENT) == AArch64II::MO_G3)
RefFlags |= AArch64MCExpr::VK_G3;
else if ((MO.getTargetFlags() & AArch64II::MO_FRAGMENT) == AArch64II::MO_G2)
RefFlags |= AArch64MCExpr::VK_G2;
else if ((MO.getTargetFlags() & AArch64II::MO_FRAGMENT) == AArch64II::MO_G1)
RefFlags |= AArch64MCExpr::VK_G1;
else if ((MO.getTargetFlags() & AArch64II::MO_FRAGMENT) == AArch64II::MO_G0)
RefFlags |= AArch64MCExpr::VK_G0;
else if ((MO.getTargetFlags() & AArch64II::MO_FRAGMENT) == AArch64II::MO_HI12)
RefFlags |= AArch64MCExpr::VK_HI12;
if (MO.getTargetFlags() & AArch64II::MO_NC)
RefFlags |= AArch64MCExpr::VK_NC;
const MCExpr *Expr =
MCSymbolRefExpr::create(Sym, MCSymbolRefExpr::VK_None, Ctx);
if (!MO.isJTI() && MO.getOffset())
Expr = MCBinaryExpr::createAdd(
Expr, MCConstantExpr::create(MO.getOffset(), Ctx), Ctx);
AArch64MCExpr::VariantKind RefKind;
RefKind = static_cast<AArch64MCExpr::VariantKind>(RefFlags);
Expr = AArch64MCExpr::create(Expr, RefKind, Ctx);
return MCOperand::createExpr(Expr);
}
MCOperand AArch64MCInstLower::lowerSymbolOperandCOFF(const MachineOperand &MO,
MCSymbol *Sym) const {
uint32_t RefFlags = 0;
if (MO.getTargetFlags() & AArch64II::MO_TLS) {
if ((MO.getTargetFlags() & AArch64II::MO_FRAGMENT) == AArch64II::MO_PAGEOFF)
RefFlags |= AArch64MCExpr::VK_SECREL_LO12;
else if ((MO.getTargetFlags() & AArch64II::MO_FRAGMENT) ==
AArch64II::MO_HI12)
RefFlags |= AArch64MCExpr::VK_SECREL_HI12;
} else if (MO.getTargetFlags() & AArch64II::MO_S) {
RefFlags |= AArch64MCExpr::VK_SABS;
} else {
RefFlags |= AArch64MCExpr::VK_ABS;
if ((MO.getTargetFlags() & AArch64II::MO_FRAGMENT) == AArch64II::MO_PAGE)
RefFlags |= AArch64MCExpr::VK_PAGE;
else if ((MO.getTargetFlags() & AArch64II::MO_FRAGMENT) ==
AArch64II::MO_PAGEOFF)
RefFlags |= AArch64MCExpr::VK_PAGEOFF | AArch64MCExpr::VK_NC;
}
if ((MO.getTargetFlags() & AArch64II::MO_FRAGMENT) == AArch64II::MO_G3)
RefFlags |= AArch64MCExpr::VK_G3;
else if ((MO.getTargetFlags() & AArch64II::MO_FRAGMENT) == AArch64II::MO_G2)
RefFlags |= AArch64MCExpr::VK_G2;
else if ((MO.getTargetFlags() & AArch64II::MO_FRAGMENT) == AArch64II::MO_G1)
RefFlags |= AArch64MCExpr::VK_G1;
else if ((MO.getTargetFlags() & AArch64II::MO_FRAGMENT) == AArch64II::MO_G0)
RefFlags |= AArch64MCExpr::VK_G0;
// FIXME: Currently we only set VK_NC for MO_G3/MO_G2/MO_G1/MO_G0. This is
// because setting VK_NC for others would mean setting their respective
// RefFlags correctly. We should do this in a separate patch.
if (MO.getTargetFlags() & AArch64II::MO_NC) {
auto MOFrag = (MO.getTargetFlags() & AArch64II::MO_FRAGMENT);
if (MOFrag == AArch64II::MO_G3 || MOFrag == AArch64II::MO_G2 ||
MOFrag == AArch64II::MO_G1 || MOFrag == AArch64II::MO_G0)
RefFlags |= AArch64MCExpr::VK_NC;
}
const MCExpr *Expr =
MCSymbolRefExpr::create(Sym, MCSymbolRefExpr::VK_None, Ctx);
if (!MO.isJTI() && MO.getOffset())
Expr = MCBinaryExpr::createAdd(
Expr, MCConstantExpr::create(MO.getOffset(), Ctx), Ctx);
auto RefKind = static_cast<AArch64MCExpr::VariantKind>(RefFlags);
assert(RefKind != AArch64MCExpr::VK_INVALID &&
"Invalid relocation requested");
Expr = AArch64MCExpr::create(Expr, RefKind, Ctx);
return MCOperand::createExpr(Expr);
}
MCOperand AArch64MCInstLower::LowerSymbolOperand(const MachineOperand &MO,
MCSymbol *Sym) const {
if (Printer.TM.getTargetTriple().isOSDarwin())
return lowerSymbolOperandDarwin(MO, Sym);
if (Printer.TM.getTargetTriple().isOSBinFormatCOFF())
return lowerSymbolOperandCOFF(MO, Sym);
assert(Printer.TM.getTargetTriple().isOSBinFormatELF() && "Invalid target");
return lowerSymbolOperandELF(MO, Sym);
}
bool AArch64MCInstLower::lowerOperand(const MachineOperand &MO,
MCOperand &MCOp) const {
switch (MO.getType()) {
default:
llvm_unreachable("unknown operand type");
case MachineOperand::MO_Register:
// Ignore all implicit register operands.
if (MO.isImplicit())
return false;
MCOp = MCOperand::createReg(MO.getReg());
break;
case MachineOperand::MO_RegisterMask:
// Regmasks are like implicit defs.
return false;
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, GetGlobalAddressSymbol(MO));
break;
case MachineOperand::MO_ExternalSymbol:
MCOp = LowerSymbolOperand(MO, GetExternalSymbolSymbol(MO));
break;
case MachineOperand::MO_MCSymbol:
MCOp = LowerSymbolOperand(MO, MO.getMCSymbol());
break;
case MachineOperand::MO_JumpTableIndex:
MCOp = LowerSymbolOperand(MO, Printer.GetJTISymbol(MO.getIndex()));
break;
case MachineOperand::MO_ConstantPoolIndex:
MCOp = LowerSymbolOperand(MO, Printer.GetCPISymbol(MO.getIndex()));
break;
case MachineOperand::MO_BlockAddress:
MCOp = LowerSymbolOperand(
MO, Printer.GetBlockAddressSymbol(MO.getBlockAddress()));
break;
}
return true;
}
void AArch64MCInstLower::Lower(const MachineInstr *MI, MCInst &OutMI) const {
OutMI.setOpcode(MI->getOpcode());
for (const MachineOperand &MO : MI->operands()) {
MCOperand MCOp;
if (lowerOperand(MO, MCOp))
OutMI.addOperand(MCOp);
}
switch (OutMI.getOpcode()) {
case AArch64::CATCHRET:
OutMI = MCInst();
OutMI.setOpcode(AArch64::RET);
OutMI.addOperand(MCOperand::createReg(AArch64::LR));
break;
case AArch64::CLEANUPRET:
OutMI = MCInst();
OutMI.setOpcode(AArch64::RET);
OutMI.addOperand(MCOperand::createReg(AArch64::LR));
break;
}
}
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