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clang-p2996/llvm/lib/Target/X86/X86AsmPrinter.cpp
Nick Desaulniers 8ec304c9fd [X86AsmPrinter] refactor static functions into private methods. NFC 
Summary:
A lot of the code for printing special cases of operands in this
translation unit are static functions. While I too have suffered many
years of abuse at the hands of C, we should prefer private methods,
particularly when you start passing around *this as your first argument,
which is a code smell.

This will help make generic vs arch specific asm printing easier, as it
brings X86AsmPrinter more in line with other arch's derived AsmPrinters.
We will then be able to more easily move architecture generic code to
the base class, and architecture specific code to the derived classes.

Some other small refactorings while we're here:
- the parameter Op is now consistently OpNo
- add spaces around binary expressions. I know we're not millionaires
  but c'mon.

Reviewers: echristo

Reviewed By: echristo

Subscribers: smeenai, hiraditya, llvm-commits, srhines, craig.topper

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D60577

llvm-svn: 358236
2019-04-11 22:47:13 +00:00

732 lines
25 KiB
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//===-- X86AsmPrinter.cpp - Convert X86 LLVM code to AT&T assembly --------===//
//
// 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 a printer that converts from our internal representation
// of machine-dependent LLVM code to X86 machine code.
//
//===----------------------------------------------------------------------===//
#include "X86AsmPrinter.h"
#include "InstPrinter/X86ATTInstPrinter.h"
#include "MCTargetDesc/X86BaseInfo.h"
#include "MCTargetDesc/X86TargetStreamer.h"
#include "X86InstrInfo.h"
#include "X86MachineFunctionInfo.h"
#include "llvm/BinaryFormat/COFF.h"
#include "llvm/BinaryFormat/ELF.h"
#include "llvm/CodeGen/MachineConstantPool.h"
#include "llvm/CodeGen/MachineModuleInfoImpls.h"
#include "llvm/CodeGen/TargetLoweringObjectFileImpl.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/InlineAsm.h"
#include "llvm/IR/Mangler.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Type.h"
#include "llvm/MC/MCCodeEmitter.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCSectionCOFF.h"
#include "llvm/MC/MCSectionELF.h"
#include "llvm/MC/MCSectionMachO.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/MachineValueType.h"
#include "llvm/Support/TargetRegistry.h"
using namespace llvm;
X86AsmPrinter::X86AsmPrinter(TargetMachine &TM,
std::unique_ptr<MCStreamer> Streamer)
: AsmPrinter(TM, std::move(Streamer)), SM(*this), FM(*this) {}
//===----------------------------------------------------------------------===//
// Primitive Helper Functions.
//===----------------------------------------------------------------------===//
/// runOnMachineFunction - Emit the function body.
///
bool X86AsmPrinter::runOnMachineFunction(MachineFunction &MF) {
Subtarget = &MF.getSubtarget<X86Subtarget>();
SMShadowTracker.startFunction(MF);
CodeEmitter.reset(TM.getTarget().createMCCodeEmitter(
*Subtarget->getInstrInfo(), *Subtarget->getRegisterInfo(),
MF.getContext()));
EmitFPOData =
Subtarget->isTargetWin32() && MF.getMMI().getModule()->getCodeViewFlag();
SetupMachineFunction(MF);
if (Subtarget->isTargetCOFF()) {
bool Local = MF.getFunction().hasLocalLinkage();
OutStreamer->BeginCOFFSymbolDef(CurrentFnSym);
OutStreamer->EmitCOFFSymbolStorageClass(
Local ? COFF::IMAGE_SYM_CLASS_STATIC : COFF::IMAGE_SYM_CLASS_EXTERNAL);
OutStreamer->EmitCOFFSymbolType(COFF::IMAGE_SYM_DTYPE_FUNCTION
<< COFF::SCT_COMPLEX_TYPE_SHIFT);
OutStreamer->EndCOFFSymbolDef();
}
// Emit the rest of the function body.
EmitFunctionBody();
// Emit the XRay table for this function.
emitXRayTable();
EmitFPOData = false;
// We didn't modify anything.
return false;
}
void X86AsmPrinter::EmitFunctionBodyStart() {
if (EmitFPOData) {
if (auto *XTS =
static_cast<X86TargetStreamer *>(OutStreamer->getTargetStreamer()))
XTS->emitFPOProc(
CurrentFnSym,
MF->getInfo<X86MachineFunctionInfo>()->getArgumentStackSize());
}
}
void X86AsmPrinter::EmitFunctionBodyEnd() {
if (EmitFPOData) {
if (auto *XTS =
static_cast<X86TargetStreamer *>(OutStreamer->getTargetStreamer()))
XTS->emitFPOEndProc();
}
}
/// PrintSymbolOperand - Print a raw symbol reference operand. This handles
/// jump tables, constant pools, global address and external symbols, all of
/// which print to a label with various suffixes for relocation types etc.
void X86AsmPrinter::PrintSymbolOperand(const MachineOperand &MO,
raw_ostream &O) {
switch (MO.getType()) {
default: llvm_unreachable("unknown symbol type!");
case MachineOperand::MO_ConstantPoolIndex:
GetCPISymbol(MO.getIndex())->print(O, MAI);
printOffset(MO.getOffset(), O);
break;
case MachineOperand::MO_GlobalAddress: {
const GlobalValue *GV = MO.getGlobal();
MCSymbol *GVSym;
if (MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY ||
MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY_PIC_BASE)
GVSym = getSymbolWithGlobalValueBase(GV, "$non_lazy_ptr");
else
GVSym = getSymbol(GV);
// Handle dllimport linkage.
if (MO.getTargetFlags() == X86II::MO_DLLIMPORT)
GVSym = OutContext.getOrCreateSymbol(Twine("__imp_") + GVSym->getName());
else if (MO.getTargetFlags() == X86II::MO_COFFSTUB)
GVSym =
OutContext.getOrCreateSymbol(Twine(".refptr.") + GVSym->getName());
if (MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY ||
MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY_PIC_BASE) {
MCSymbol *Sym = getSymbolWithGlobalValueBase(GV, "$non_lazy_ptr");
MachineModuleInfoImpl::StubValueTy &StubSym =
MMI->getObjFileInfo<MachineModuleInfoMachO>().getGVStubEntry(Sym);
if (!StubSym.getPointer())
StubSym = MachineModuleInfoImpl::StubValueTy(getSymbol(GV),
!GV->hasInternalLinkage());
}
// If the name begins with a dollar-sign, enclose it in parens. We do this
// to avoid having it look like an integer immediate to the assembler.
if (GVSym->getName()[0] != '$')
GVSym->print(O, MAI);
else {
O << '(';
GVSym->print(O, MAI);
O << ')';
}
printOffset(MO.getOffset(), O);
break;
}
}
switch (MO.getTargetFlags()) {
default:
llvm_unreachable("Unknown target flag on GV operand");
case X86II::MO_NO_FLAG: // No flag.
break;
case X86II::MO_DARWIN_NONLAZY:
case X86II::MO_DLLIMPORT:
case X86II::MO_COFFSTUB:
// These affect the name of the symbol, not any suffix.
break;
case X86II::MO_GOT_ABSOLUTE_ADDRESS:
O << " + [.-";
MF->getPICBaseSymbol()->print(O, MAI);
O << ']';
break;
case X86II::MO_PIC_BASE_OFFSET:
case X86II::MO_DARWIN_NONLAZY_PIC_BASE:
O << '-';
MF->getPICBaseSymbol()->print(O, MAI);
break;
case X86II::MO_TLSGD: O << "@TLSGD"; break;
case X86II::MO_TLSLD: O << "@TLSLD"; break;
case X86II::MO_TLSLDM: O << "@TLSLDM"; break;
case X86II::MO_GOTTPOFF: O << "@GOTTPOFF"; break;
case X86II::MO_INDNTPOFF: O << "@INDNTPOFF"; break;
case X86II::MO_TPOFF: O << "@TPOFF"; break;
case X86II::MO_DTPOFF: O << "@DTPOFF"; break;
case X86II::MO_NTPOFF: O << "@NTPOFF"; break;
case X86II::MO_GOTNTPOFF: O << "@GOTNTPOFF"; break;
case X86II::MO_GOTPCREL: O << "@GOTPCREL"; break;
case X86II::MO_GOT: O << "@GOT"; break;
case X86II::MO_GOTOFF: O << "@GOTOFF"; break;
case X86II::MO_PLT: O << "@PLT"; break;
case X86II::MO_TLVP: O << "@TLVP"; break;
case X86II::MO_TLVP_PIC_BASE:
O << "@TLVP" << '-';
MF->getPICBaseSymbol()->print(O, MAI);
break;
case X86II::MO_SECREL: O << "@SECREL32"; break;
}
}
void X86AsmPrinter::PrintOperand(const MachineInstr *MI, unsigned OpNo,
raw_ostream &O) {
const MachineOperand &MO = MI->getOperand(OpNo);
const bool IsATT = MI->getInlineAsmDialect() == InlineAsm::AD_ATT;
switch (MO.getType()) {
default: llvm_unreachable("unknown operand type!");
case MachineOperand::MO_Register: {
if (IsATT)
O << '%';
O << X86ATTInstPrinter::getRegisterName(MO.getReg());
return;
}
case MachineOperand::MO_Immediate:
if (IsATT)
O << '$';
O << MO.getImm();
return;
case MachineOperand::MO_GlobalAddress: {
if (IsATT)
O << '$';
PrintSymbolOperand(MO, O);
break;
}
case MachineOperand::MO_BlockAddress: {
MCSymbol *Sym = GetBlockAddressSymbol(MO.getBlockAddress());
Sym->print(O, MAI);
break;
}
}
}
/// PrintModifiedOperand - Print subregisters based on supplied modifier,
/// deferring to PrintOperand() if no modifier was supplied or if operand is not
/// a register.
void X86AsmPrinter::PrintModifiedOperand(const MachineInstr *MI, unsigned OpNo,
raw_ostream &O, const char *Modifier) {
const MachineOperand &MO = MI->getOperand(OpNo);
if (!Modifier || MO.getType() != MachineOperand::MO_Register)
return PrintOperand(MI, OpNo, O);
if (MI->getInlineAsmDialect() == InlineAsm::AD_ATT)
O << '%';
unsigned Reg = MO.getReg();
if (strncmp(Modifier, "subreg", strlen("subreg")) == 0) {
unsigned Size = (strcmp(Modifier+6,"64") == 0) ? 64 :
(strcmp(Modifier+6,"32") == 0) ? 32 :
(strcmp(Modifier+6,"16") == 0) ? 16 : 8;
Reg = getX86SubSuperRegister(Reg, Size);
}
O << X86ATTInstPrinter::getRegisterName(Reg);
}
/// PrintPCRelImm - This is used to print an immediate value that ends up
/// being encoded as a pc-relative value. These print slightly differently, for
/// example, a $ is not emitted.
void X86AsmPrinter::PrintPCRelImm(const MachineInstr *MI, unsigned OpNo,
raw_ostream &O) {
const MachineOperand &MO = MI->getOperand(OpNo);
switch (MO.getType()) {
default: llvm_unreachable("Unknown pcrel immediate operand");
case MachineOperand::MO_Register:
// pc-relativeness was handled when computing the value in the reg.
PrintOperand(MI, OpNo, O);
return;
case MachineOperand::MO_Immediate:
O << MO.getImm();
return;
case MachineOperand::MO_GlobalAddress:
PrintSymbolOperand(MO, O);
return;
}
}
void X86AsmPrinter::PrintLeaMemReference(const MachineInstr *MI, unsigned OpNo,
raw_ostream &O, const char *Modifier) {
const MachineOperand &BaseReg = MI->getOperand(OpNo + X86::AddrBaseReg);
const MachineOperand &IndexReg = MI->getOperand(OpNo + X86::AddrIndexReg);
const MachineOperand &DispSpec = MI->getOperand(OpNo + X86::AddrDisp);
// If we really don't want to print out (rip), don't.
bool HasBaseReg = BaseReg.getReg() != 0;
if (HasBaseReg && Modifier && !strcmp(Modifier, "no-rip") &&
BaseReg.getReg() == X86::RIP)
HasBaseReg = false;
// HasParenPart - True if we will print out the () part of the mem ref.
bool HasParenPart = IndexReg.getReg() || HasBaseReg;
switch (DispSpec.getType()) {
default:
llvm_unreachable("unknown operand type!");
case MachineOperand::MO_Immediate: {
int DispVal = DispSpec.getImm();
if (DispVal || !HasParenPart)
O << DispVal;
break;
}
case MachineOperand::MO_GlobalAddress:
case MachineOperand::MO_ConstantPoolIndex:
PrintSymbolOperand(DispSpec, O);
}
if (Modifier && strcmp(Modifier, "H") == 0)
O << "+8";
if (HasParenPart) {
assert(IndexReg.getReg() != X86::ESP &&
"X86 doesn't allow scaling by ESP");
O << '(';
if (HasBaseReg)
PrintModifiedOperand(MI, OpNo + X86::AddrBaseReg, O, Modifier);
if (IndexReg.getReg()) {
O << ',';
PrintModifiedOperand(MI, OpNo + X86::AddrIndexReg, O, Modifier);
unsigned ScaleVal = MI->getOperand(OpNo + X86::AddrScaleAmt).getImm();
if (ScaleVal != 1)
O << ',' << ScaleVal;
}
O << ')';
}
}
void X86AsmPrinter::PrintMemReference(const MachineInstr *MI, unsigned OpNo,
raw_ostream &O, const char *Modifier) {
assert(isMem(*MI, OpNo) && "Invalid memory reference!");
const MachineOperand &Segment = MI->getOperand(OpNo + X86::AddrSegmentReg);
if (Segment.getReg()) {
PrintModifiedOperand(MI, OpNo + X86::AddrSegmentReg, O, Modifier);
O << ':';
}
PrintLeaMemReference(MI, OpNo, O, Modifier);
}
void X86AsmPrinter::PrintIntelMemReference(const MachineInstr *MI,
unsigned OpNo, raw_ostream &O) {
const MachineOperand &BaseReg = MI->getOperand(OpNo + X86::AddrBaseReg);
unsigned ScaleVal = MI->getOperand(OpNo + X86::AddrScaleAmt).getImm();
const MachineOperand &IndexReg = MI->getOperand(OpNo + X86::AddrIndexReg);
const MachineOperand &DispSpec = MI->getOperand(OpNo + X86::AddrDisp);
const MachineOperand &SegReg = MI->getOperand(OpNo + X86::AddrSegmentReg);
// If this has a segment register, print it.
if (SegReg.getReg()) {
PrintOperand(MI, OpNo + X86::AddrSegmentReg, O);
O << ':';
}
O << '[';
bool NeedPlus = false;
if (BaseReg.getReg()) {
PrintOperand(MI, OpNo + X86::AddrBaseReg, O);
NeedPlus = true;
}
if (IndexReg.getReg()) {
if (NeedPlus) O << " + ";
if (ScaleVal != 1)
O << ScaleVal << '*';
PrintOperand(MI, OpNo + X86::AddrIndexReg, O);
NeedPlus = true;
}
if (!DispSpec.isImm()) {
if (NeedPlus) O << " + ";
PrintOperand(MI, OpNo + X86::AddrDisp, O);
} else {
int64_t DispVal = DispSpec.getImm();
if (DispVal || (!IndexReg.getReg() && !BaseReg.getReg())) {
if (NeedPlus) {
if (DispVal > 0)
O << " + ";
else {
O << " - ";
DispVal = -DispVal;
}
}
O << DispVal;
}
}
O << ']';
}
static bool printAsmMRegister(X86AsmPrinter &P, const MachineOperand &MO,
char Mode, raw_ostream &O) {
unsigned Reg = MO.getReg();
bool EmitPercent = true;
if (!X86::GR8RegClass.contains(Reg) &&
!X86::GR16RegClass.contains(Reg) &&
!X86::GR32RegClass.contains(Reg) &&
!X86::GR64RegClass.contains(Reg))
return true;
switch (Mode) {
default: return true; // Unknown mode.
case 'b': // Print QImode register
Reg = getX86SubSuperRegister(Reg, 8);
break;
case 'h': // Print QImode high register
Reg = getX86SubSuperRegister(Reg, 8, true);
break;
case 'w': // Print HImode register
Reg = getX86SubSuperRegister(Reg, 16);
break;
case 'k': // Print SImode register
Reg = getX86SubSuperRegister(Reg, 32);
break;
case 'V':
EmitPercent = false;
LLVM_FALLTHROUGH;
case 'q':
// Print 64-bit register names if 64-bit integer registers are available.
// Otherwise, print 32-bit register names.
Reg = getX86SubSuperRegister(Reg, P.getSubtarget().is64Bit() ? 64 : 32);
break;
}
if (EmitPercent)
O << '%';
O << X86ATTInstPrinter::getRegisterName(Reg);
return false;
}
/// PrintAsmOperand - Print out an operand for an inline asm expression.
///
bool X86AsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
const char *ExtraCode, raw_ostream &O) {
// Does this asm operand have a single letter operand modifier?
if (ExtraCode && ExtraCode[0]) {
if (ExtraCode[1] != 0) return true; // Unknown modifier.
const MachineOperand &MO = MI->getOperand(OpNo);
switch (ExtraCode[0]) {
default:
// See if this is a generic print operand
return AsmPrinter::PrintAsmOperand(MI, OpNo, ExtraCode, O);
case 'a': // This is an address. Currently only 'i' and 'r' are expected.
switch (MO.getType()) {
default:
return true;
case MachineOperand::MO_Immediate:
O << MO.getImm();
return false;
case MachineOperand::MO_ConstantPoolIndex:
case MachineOperand::MO_JumpTableIndex:
case MachineOperand::MO_ExternalSymbol:
llvm_unreachable("unexpected operand type!");
case MachineOperand::MO_GlobalAddress:
PrintSymbolOperand(MO, O);
if (Subtarget->isPICStyleRIPRel())
O << "(%rip)";
return false;
case MachineOperand::MO_Register:
O << '(';
PrintOperand(MI, OpNo, O);
O << ')';
return false;
}
case 'c': // Don't print "$" before a global var name or constant.
switch (MO.getType()) {
default:
PrintOperand(MI, OpNo, O);
break;
case MachineOperand::MO_Immediate:
O << MO.getImm();
break;
case MachineOperand::MO_ConstantPoolIndex:
case MachineOperand::MO_JumpTableIndex:
case MachineOperand::MO_ExternalSymbol:
llvm_unreachable("unexpected operand type!");
case MachineOperand::MO_GlobalAddress:
PrintSymbolOperand(MO, O);
break;
}
return false;
case 'A': // Print '*' before a register (it must be a register)
if (MO.isReg()) {
O << '*';
PrintOperand(MI, OpNo, O);
return false;
}
return true;
case 'b': // Print QImode register
case 'h': // Print QImode high register
case 'w': // Print HImode register
case 'k': // Print SImode register
case 'q': // Print DImode register
case 'V': // Print native register without '%'
if (MO.isReg())
return printAsmMRegister(*this, MO, ExtraCode[0], O);
PrintOperand(MI, OpNo, O);
return false;
case 'P': // This is the operand of a call, treat specially.
PrintPCRelImm(MI, OpNo, O);
return false;
case 'n': // Negate the immediate or print a '-' before the operand.
// Note: this is a temporary solution. It should be handled target
// independently as part of the 'MC' work.
if (MO.isImm()) {
O << -MO.getImm();
return false;
}
O << '-';
}
}
PrintOperand(MI, OpNo, O);
return false;
}
bool X86AsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNo,
const char *ExtraCode,
raw_ostream &O) {
if (MI->getInlineAsmDialect() == InlineAsm::AD_Intel) {
PrintIntelMemReference(MI, OpNo, O);
return false;
}
if (ExtraCode && ExtraCode[0]) {
if (ExtraCode[1] != 0) return true; // Unknown modifier.
switch (ExtraCode[0]) {
default: return true; // Unknown modifier.
case 'b': // Print QImode register
case 'h': // Print QImode high register
case 'w': // Print HImode register
case 'k': // Print SImode register
case 'q': // Print SImode register
// These only apply to registers, ignore on mem.
break;
case 'H':
PrintMemReference(MI, OpNo, O, "H");
return false;
case 'P': // Don't print @PLT, but do print as memory.
PrintMemReference(MI, OpNo, O, "no-rip");
return false;
}
}
PrintMemReference(MI, OpNo, O, nullptr);
return false;
}
void X86AsmPrinter::EmitStartOfAsmFile(Module &M) {
const Triple &TT = TM.getTargetTriple();
if (TT.isOSBinFormatELF()) {
// Assemble feature flags that may require creation of a note section.
unsigned FeatureFlagsAnd = 0;
if (M.getModuleFlag("cf-protection-branch"))
FeatureFlagsAnd |= ELF::GNU_PROPERTY_X86_FEATURE_1_IBT;
if (M.getModuleFlag("cf-protection-return"))
FeatureFlagsAnd |= ELF::GNU_PROPERTY_X86_FEATURE_1_SHSTK;
if (FeatureFlagsAnd) {
// Emit a .note.gnu.property section with the flags.
if (!TT.isArch32Bit() && !TT.isArch64Bit())
llvm_unreachable("CFProtection used on invalid architecture!");
MCSection *Cur = OutStreamer->getCurrentSectionOnly();
MCSection *Nt = MMI->getContext().getELFSection(
".note.gnu.property", ELF::SHT_NOTE, ELF::SHF_ALLOC);
OutStreamer->SwitchSection(Nt);
// Emitting note header.
int WordSize = TT.isArch64Bit() ? 8 : 4;
EmitAlignment(WordSize == 4 ? 2 : 3);
OutStreamer->EmitIntValue(4, 4 /*size*/); // data size for "GNU\0"
OutStreamer->EmitIntValue(8 + WordSize, 4 /*size*/); // Elf_Prop size
OutStreamer->EmitIntValue(ELF::NT_GNU_PROPERTY_TYPE_0, 4 /*size*/);
OutStreamer->EmitBytes(StringRef("GNU", 4)); // note name
// Emitting an Elf_Prop for the CET properties.
OutStreamer->EmitIntValue(ELF::GNU_PROPERTY_X86_FEATURE_1_AND, 4);
OutStreamer->EmitIntValue(4, 4); // data size
OutStreamer->EmitIntValue(FeatureFlagsAnd, 4); // data
EmitAlignment(WordSize == 4 ? 2 : 3); // padding
OutStreamer->endSection(Nt);
OutStreamer->SwitchSection(Cur);
}
}
if (TT.isOSBinFormatMachO())
OutStreamer->SwitchSection(getObjFileLowering().getTextSection());
if (TT.isOSBinFormatCOFF()) {
// Emit an absolute @feat.00 symbol. This appears to be some kind of
// compiler features bitfield read by link.exe.
MCSymbol *S = MMI->getContext().getOrCreateSymbol(StringRef("@feat.00"));
OutStreamer->BeginCOFFSymbolDef(S);
OutStreamer->EmitCOFFSymbolStorageClass(COFF::IMAGE_SYM_CLASS_STATIC);
OutStreamer->EmitCOFFSymbolType(COFF::IMAGE_SYM_DTYPE_NULL);
OutStreamer->EndCOFFSymbolDef();
int64_t Feat00Flags = 0;
if (TT.getArch() == Triple::x86) {
// According to the PE-COFF spec, the LSB of this value marks the object
// for "registered SEH". This means that all SEH handler entry points
// must be registered in .sxdata. Use of any unregistered handlers will
// cause the process to terminate immediately. LLVM does not know how to
// register any SEH handlers, so its object files should be safe.
Feat00Flags |= 1;
}
if (M.getModuleFlag("cfguardtable"))
Feat00Flags |= 0x800; // Object is CFG-aware.
OutStreamer->EmitSymbolAttribute(S, MCSA_Global);
OutStreamer->EmitAssignment(
S, MCConstantExpr::create(Feat00Flags, MMI->getContext()));
}
OutStreamer->EmitSyntaxDirective();
// If this is not inline asm and we're in 16-bit
// mode prefix assembly with .code16.
bool is16 = TT.getEnvironment() == Triple::CODE16;
if (M.getModuleInlineAsm().empty() && is16)
OutStreamer->EmitAssemblerFlag(MCAF_Code16);
}
static void
emitNonLazySymbolPointer(MCStreamer &OutStreamer, MCSymbol *StubLabel,
MachineModuleInfoImpl::StubValueTy &MCSym) {
// L_foo$stub:
OutStreamer.EmitLabel(StubLabel);
// .indirect_symbol _foo
OutStreamer.EmitSymbolAttribute(MCSym.getPointer(), MCSA_IndirectSymbol);
if (MCSym.getInt())
// External to current translation unit.
OutStreamer.EmitIntValue(0, 4/*size*/);
else
// Internal to current translation unit.
//
// When we place the LSDA into the TEXT section, the type info
// pointers need to be indirect and pc-rel. We accomplish this by
// using NLPs; however, sometimes the types are local to the file.
// We need to fill in the value for the NLP in those cases.
OutStreamer.EmitValue(
MCSymbolRefExpr::create(MCSym.getPointer(), OutStreamer.getContext()),
4 /*size*/);
}
static void emitNonLazyStubs(MachineModuleInfo *MMI, MCStreamer &OutStreamer) {
MachineModuleInfoMachO &MMIMacho =
MMI->getObjFileInfo<MachineModuleInfoMachO>();
// Output stubs for dynamically-linked functions.
MachineModuleInfoMachO::SymbolListTy Stubs;
// Output stubs for external and common global variables.
Stubs = MMIMacho.GetGVStubList();
if (!Stubs.empty()) {
OutStreamer.SwitchSection(MMI->getContext().getMachOSection(
"__IMPORT", "__pointers", MachO::S_NON_LAZY_SYMBOL_POINTERS,
SectionKind::getMetadata()));
for (auto &Stub : Stubs)
emitNonLazySymbolPointer(OutStreamer, Stub.first, Stub.second);
Stubs.clear();
OutStreamer.AddBlankLine();
}
}
void X86AsmPrinter::EmitEndOfAsmFile(Module &M) {
const Triple &TT = TM.getTargetTriple();
if (TT.isOSBinFormatMachO()) {
// Mach-O uses non-lazy symbol stubs to encode per-TU information into
// global table for symbol lookup.
emitNonLazyStubs(MMI, *OutStreamer);
// Emit stack and fault map information.
emitStackMaps(SM);
FM.serializeToFaultMapSection();
// This flag tells the linker that no global symbols contain code that fall
// through to other global symbols (e.g. an implementation of multiple entry
// points). If this doesn't occur, the linker can safely perform dead code
// stripping. Since LLVM never generates code that does this, it is always
// safe to set.
OutStreamer->EmitAssemblerFlag(MCAF_SubsectionsViaSymbols);
} else if (TT.isOSBinFormatCOFF()) {
if (MMI->usesMSVCFloatingPoint()) {
// In Windows' libcmt.lib, there is a file which is linked in only if the
// symbol _fltused is referenced. Linking this in causes some
// side-effects:
//
// 1. For x86-32, it will set the x87 rounding mode to 53-bit instead of
// 64-bit mantissas at program start.
//
// 2. It links in support routines for floating-point in scanf and printf.
//
// MSVC emits an undefined reference to _fltused when there are any
// floating point operations in the program (including calls). A program
// that only has: `scanf("%f", &global_float);` may fail to trigger this,
// but oh well...that's a documented issue.
StringRef SymbolName =
(TT.getArch() == Triple::x86) ? "__fltused" : "_fltused";
MCSymbol *S = MMI->getContext().getOrCreateSymbol(SymbolName);
OutStreamer->EmitSymbolAttribute(S, MCSA_Global);
return;
}
emitStackMaps(SM);
} else if (TT.isOSBinFormatELF()) {
emitStackMaps(SM);
FM.serializeToFaultMapSection();
}
}
//===----------------------------------------------------------------------===//
// Target Registry Stuff
//===----------------------------------------------------------------------===//
// Force static initialization.
extern "C" void LLVMInitializeX86AsmPrinter() {
RegisterAsmPrinter<X86AsmPrinter> X(getTheX86_32Target());
RegisterAsmPrinter<X86AsmPrinter> Y(getTheX86_64Target());
}
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