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llvm-6502/lib/Target/X86/X86AsmPrinter.cpp
David Majnemer 38d8be1ad8 CodeGen: Stick constant pool entries in COMDAT sections for WinCOFF 
COFF lacks a feature that other object file formats support: mergeable
sections.

To work around this, MSVC sticks constant pool entries in special COMDAT
sections so that each constant is in it's own section.  This permits
unused constants to be dropped and it also allows duplicate constants in
different translation units to get merged together.

This fixes PR20262.

Differential Revision: http://reviews.llvm.org/D4482

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213006 91177308-0d34-0410-b5e6-96231b3b80d8
2014-07-14 22:57:27 +00:00

749 lines
26 KiB
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//===-- X86AsmPrinter.cpp - Convert X86 LLVM code to AT&T assembly --------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// 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 "X86InstrInfo.h"
#include "X86MachineFunctionInfo.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/CodeGen/MachineConstantPool.h"
#include "llvm/CodeGen/MachineModuleInfoImpls.h"
#include "llvm/CodeGen/MachineValueType.h"
#include "llvm/CodeGen/TargetLoweringObjectFileImpl.h"
#include "llvm/IR/DebugInfo.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/Mangler.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Type.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCSectionCOFF.h"
#include "llvm/MC/MCSectionMachO.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/Support/COFF.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/TargetRegistry.h"
using namespace llvm;
//===----------------------------------------------------------------------===//
// Primitive Helper Functions.
//===----------------------------------------------------------------------===//
/// runOnMachineFunction - Emit the function body.
///
bool X86AsmPrinter::runOnMachineFunction(MachineFunction &MF) {
SetupMachineFunction(MF);
if (Subtarget->isTargetCOFF()) {
bool Intrn = MF.getFunction()->hasInternalLinkage();
OutStreamer.BeginCOFFSymbolDef(CurrentFnSym);
OutStreamer.EmitCOFFSymbolStorageClass(Intrn ? COFF::IMAGE_SYM_CLASS_STATIC
: COFF::IMAGE_SYM_CLASS_EXTERNAL);
OutStreamer.EmitCOFFSymbolType(COFF::IMAGE_SYM_DTYPE_FUNCTION
<< COFF::SCT_COMPLEX_TYPE_SHIFT);
OutStreamer.EndCOFFSymbolDef();
}
// Have common code print out the function header with linkage info etc.
EmitFunctionHeader();
// Emit the rest of the function body.
EmitFunctionBody();
// We didn't modify anything.
return false;
}
/// 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.
static void printSymbolOperand(X86AsmPrinter &P, const MachineOperand &MO,
raw_ostream &O) {
switch (MO.getType()) {
default: llvm_unreachable("unknown symbol type!");
case MachineOperand::MO_ConstantPoolIndex:
O << *P.GetCPISymbol(MO.getIndex());
P.printOffset(MO.getOffset(), O);
break;
case MachineOperand::MO_GlobalAddress: {
const GlobalValue *GV = MO.getGlobal();
MCSymbol *GVSym;
if (MO.getTargetFlags() == X86II::MO_DARWIN_STUB)
GVSym = P.getSymbolWithGlobalValueBase(GV, "$stub");
else if (MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY ||
MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY_PIC_BASE ||
MO.getTargetFlags() == X86II::MO_DARWIN_HIDDEN_NONLAZY_PIC_BASE)
GVSym = P.getSymbolWithGlobalValueBase(GV, "$non_lazy_ptr");
else
GVSym = P.getSymbol(GV);
// Handle dllimport linkage.
if (MO.getTargetFlags() == X86II::MO_DLLIMPORT)
GVSym =
P.OutContext.GetOrCreateSymbol(Twine("__imp_") + GVSym->getName());
if (MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY ||
MO.getTargetFlags() == X86II::MO_DARWIN_NONLAZY_PIC_BASE) {
MCSymbol *Sym = P.getSymbolWithGlobalValueBase(GV, "$non_lazy_ptr");
MachineModuleInfoImpl::StubValueTy &StubSym =
P.MMI->getObjFileInfo<MachineModuleInfoMachO>().getGVStubEntry(Sym);
if (!StubSym.getPointer())
StubSym = MachineModuleInfoImpl::
StubValueTy(P.getSymbol(GV), !GV->hasInternalLinkage());
} else if (MO.getTargetFlags() == X86II::MO_DARWIN_HIDDEN_NONLAZY_PIC_BASE){
MCSymbol *Sym = P.getSymbolWithGlobalValueBase(GV, "$non_lazy_ptr");
MachineModuleInfoImpl::StubValueTy &StubSym =
P.MMI->getObjFileInfo<MachineModuleInfoMachO>().getHiddenGVStubEntry(
Sym);
if (!StubSym.getPointer())
StubSym = MachineModuleInfoImpl::
StubValueTy(P.getSymbol(GV), !GV->hasInternalLinkage());
} else if (MO.getTargetFlags() == X86II::MO_DARWIN_STUB) {
MCSymbol *Sym = P.getSymbolWithGlobalValueBase(GV, "$stub");
MachineModuleInfoImpl::StubValueTy &StubSym =
P.MMI->getObjFileInfo<MachineModuleInfoMachO>().getFnStubEntry(Sym);
if (!StubSym.getPointer())
StubSym = MachineModuleInfoImpl::
StubValueTy(P.getSymbol(GV), !GV->hasInternalLinkage());
}
// If the name begins with a dollar-sign, enclose it in parens. We do this
// to avoid having it look like an integer immediate to the assembler.
if (GVSym->getName()[0] != '$')
O << *GVSym;
else
O << '(' << *GVSym << ')';
P.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_DARWIN_STUB:
// These affect the name of the symbol, not any suffix.
break;
case X86II::MO_GOT_ABSOLUTE_ADDRESS:
O << " + [.-" << *P.MF->getPICBaseSymbol() << ']';
break;
case X86II::MO_PIC_BASE_OFFSET:
case X86II::MO_DARWIN_NONLAZY_PIC_BASE:
case X86II::MO_DARWIN_HIDDEN_NONLAZY_PIC_BASE:
O << '-' << *P.MF->getPICBaseSymbol();
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" << '-' << *P.MF->getPICBaseSymbol();
break;
case X86II::MO_SECREL: O << "@SECREL32"; break;
}
}
static void printOperand(X86AsmPrinter &P, const MachineInstr *MI,
unsigned OpNo, raw_ostream &O,
const char *Modifier = nullptr, unsigned AsmVariant = 0);
/// 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.
static void printPCRelImm(X86AsmPrinter &P, 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(P, MI, OpNo, O);
return;
case MachineOperand::MO_Immediate:
O << MO.getImm();
return;
case MachineOperand::MO_GlobalAddress:
printSymbolOperand(P, MO, O);
return;
}
}
static void printOperand(X86AsmPrinter &P, const MachineInstr *MI,
unsigned OpNo, raw_ostream &O, const char *Modifier,
unsigned AsmVariant) {
const MachineOperand &MO = MI->getOperand(OpNo);
switch (MO.getType()) {
default: llvm_unreachable("unknown operand type!");
case MachineOperand::MO_Register: {
// FIXME: Enumerating AsmVariant, so we can remove magic number.
if (AsmVariant == 0) O << '%';
unsigned Reg = MO.getReg();
if (Modifier && strncmp(Modifier, "subreg", strlen("subreg")) == 0) {
MVT::SimpleValueType VT = (strcmp(Modifier+6,"64") == 0) ?
MVT::i64 : ((strcmp(Modifier+6, "32") == 0) ? MVT::i32 :
((strcmp(Modifier+6,"16") == 0) ? MVT::i16 : MVT::i8));
Reg = getX86SubSuperRegister(Reg, VT);
}
O << X86ATTInstPrinter::getRegisterName(Reg);
return;
}
case MachineOperand::MO_Immediate:
if (AsmVariant == 0) O << '$';
O << MO.getImm();
return;
case MachineOperand::MO_GlobalAddress: {
if (AsmVariant == 0) O << '$';
printSymbolOperand(P, MO, O);
break;
}
}
}
static void printLeaMemReference(X86AsmPrinter &P, const MachineInstr *MI,
unsigned Op, raw_ostream &O,
const char *Modifier = nullptr) {
const MachineOperand &BaseReg = MI->getOperand(Op+X86::AddrBaseReg);
const MachineOperand &IndexReg = MI->getOperand(Op+X86::AddrIndexReg);
const MachineOperand &DispSpec = MI->getOperand(Op+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(P, 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)
printOperand(P, MI, Op+X86::AddrBaseReg, O, Modifier);
if (IndexReg.getReg()) {
O << ',';
printOperand(P, MI, Op+X86::AddrIndexReg, O, Modifier);
unsigned ScaleVal = MI->getOperand(Op+X86::AddrScaleAmt).getImm();
if (ScaleVal != 1)
O << ',' << ScaleVal;
}
O << ')';
}
}
static void printMemReference(X86AsmPrinter &P, const MachineInstr *MI,
unsigned Op, raw_ostream &O,
const char *Modifier = nullptr) {
assert(isMem(MI, Op) && "Invalid memory reference!");
const MachineOperand &Segment = MI->getOperand(Op+X86::AddrSegmentReg);
if (Segment.getReg()) {
printOperand(P, MI, Op+X86::AddrSegmentReg, O, Modifier);
O << ':';
}
printLeaMemReference(P, MI, Op, O, Modifier);
}
static void printIntelMemReference(X86AsmPrinter &P, const MachineInstr *MI,
unsigned Op, raw_ostream &O,
const char *Modifier = nullptr,
unsigned AsmVariant = 1) {
const MachineOperand &BaseReg = MI->getOperand(Op+X86::AddrBaseReg);
unsigned ScaleVal = MI->getOperand(Op+X86::AddrScaleAmt).getImm();
const MachineOperand &IndexReg = MI->getOperand(Op+X86::AddrIndexReg);
const MachineOperand &DispSpec = MI->getOperand(Op+X86::AddrDisp);
const MachineOperand &SegReg = MI->getOperand(Op+X86::AddrSegmentReg);
// If this has a segment register, print it.
if (SegReg.getReg()) {
printOperand(P, MI, Op+X86::AddrSegmentReg, O, Modifier, AsmVariant);
O << ':';
}
O << '[';
bool NeedPlus = false;
if (BaseReg.getReg()) {
printOperand(P, MI, Op+X86::AddrBaseReg, O, Modifier, AsmVariant);
NeedPlus = true;
}
if (IndexReg.getReg()) {
if (NeedPlus) O << " + ";
if (ScaleVal != 1)
O << ScaleVal << '*';
printOperand(P, MI, Op+X86::AddrIndexReg, O, Modifier, AsmVariant);
NeedPlus = true;
}
if (!DispSpec.isImm()) {
if (NeedPlus) O << " + ";
printOperand(P, MI, Op+X86::AddrDisp, O, Modifier, AsmVariant);
} 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();
switch (Mode) {
default: return true; // Unknown mode.
case 'b': // Print QImode register
Reg = getX86SubSuperRegister(Reg, MVT::i8);
break;
case 'h': // Print QImode high register
Reg = getX86SubSuperRegister(Reg, MVT::i8, true);
break;
case 'w': // Print HImode register
Reg = getX86SubSuperRegister(Reg, MVT::i16);
break;
case 'k': // Print SImode register
Reg = getX86SubSuperRegister(Reg, MVT::i32);
break;
case 'q':
// Print 64-bit register names if 64-bit integer registers are available.
// Otherwise, print 32-bit register names.
MVT::SimpleValueType Ty = P.getSubtarget().is64Bit() ? MVT::i64 : MVT::i32;
Reg = getX86SubSuperRegister(Reg, Ty);
break;
}
O << '%' << X86ATTInstPrinter::getRegisterName(Reg);
return false;
}
/// PrintAsmOperand - Print out an operand for an inline asm expression.
///
bool X86AsmPrinter::PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
unsigned AsmVariant,
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, AsmVariant, 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(*this, MO, O);
if (Subtarget->isPICStyleRIPRel())
O << "(%rip)";
return false;
case MachineOperand::MO_Register:
O << '(';
printOperand(*this, MI, OpNo, O);
O << ')';
return false;
}
case 'c': // Don't print "$" before a global var name or constant.
switch (MO.getType()) {
default:
printOperand(*this, 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(*this, MO, O);
break;
}
return false;
case 'A': // Print '*' before a register (it must be a register)
if (MO.isReg()) {
O << '*';
printOperand(*this, 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
if (MO.isReg())
return printAsmMRegister(*this, MO, ExtraCode[0], O);
printOperand(*this, MI, OpNo, O);
return false;
case 'P': // This is the operand of a call, treat specially.
printPCRelImm(*this, 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(*this, MI, OpNo, O, /*Modifier*/ nullptr, AsmVariant);
return false;
}
bool X86AsmPrinter::PrintAsmMemoryOperand(const MachineInstr *MI,
unsigned OpNo, unsigned AsmVariant,
const char *ExtraCode,
raw_ostream &O) {
if (AsmVariant) {
printIntelMemReference(*this, 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(*this, MI, OpNo, O, "H");
return false;
case 'P': // Don't print @PLT, but do print as memory.
printMemReference(*this, MI, OpNo, O, "no-rip");
return false;
}
}
printMemReference(*this, MI, OpNo, O);
return false;
}
void X86AsmPrinter::EmitStartOfAsmFile(Module &M) {
if (Subtarget->isTargetMacho())
OutStreamer.SwitchSection(getObjFileLowering().getTextSection());
if (Subtarget->isTargetCOFF()) {
// Emit an absolute @feat.00 symbol. This appears to be some kind of
// compiler features bitfield read by link.exe.
if (!Subtarget->is64Bit()) {
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();
// 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.
S->setAbsolute();
OutStreamer.EmitSymbolAttribute(S, MCSA_Global);
OutStreamer.EmitAssignment(
S, MCConstantExpr::Create(int64_t(1), MMI->getContext()));
}
}
}
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*/);
}
MCSymbol *X86AsmPrinter::GetCPISymbol(unsigned CPID) const {
if (Subtarget->isTargetKnownWindowsMSVC()) {
const MachineConstantPoolEntry &CPE =
MF->getConstantPool()->getConstants()[CPID];
if (!CPE.isMachineConstantPoolEntry()) {
SectionKind Kind = CPE.getSectionKind(TM.getDataLayout());
const Constant *C = CPE.Val.ConstVal;
const MCSectionCOFF *S = cast<MCSectionCOFF>(
getObjFileLowering().getSectionForConstant(Kind, C));
if (MCSymbol *Sym = S->getCOMDATSymbol()) {
if (Sym->isUndefined())
OutStreamer.EmitSymbolAttribute(Sym, MCSA_Global);
return Sym;
}
}
}
return AsmPrinter::GetCPISymbol(CPID);
}
void X86AsmPrinter::GenerateExportDirective(const MCSymbol *Sym, bool IsData) {
SmallString<128> Directive;
raw_svector_ostream OS(Directive);
StringRef Name = Sym->getName();
if (Subtarget->isTargetKnownWindowsMSVC())
OS << " /EXPORT:";
else
OS << " -export:";
if ((Subtarget->isTargetWindowsGNU() || Subtarget->isTargetWindowsCygwin()) &&
(Name[0] == getDataLayout().getGlobalPrefix()))
Name = Name.drop_front();
OS << Name;
if (IsData) {
if (Subtarget->isTargetKnownWindowsMSVC())
OS << ",DATA";
else
OS << ",data";
}
OS.flush();
OutStreamer.EmitBytes(Directive);
}
void X86AsmPrinter::EmitEndOfAsmFile(Module &M) {
if (Subtarget->isTargetMacho()) {
// All darwin targets use mach-o.
MachineModuleInfoMachO &MMIMacho =
MMI->getObjFileInfo<MachineModuleInfoMachO>();
// Output stubs for dynamically-linked functions.
MachineModuleInfoMachO::SymbolListTy Stubs;
Stubs = MMIMacho.GetFnStubList();
if (!Stubs.empty()) {
const MCSection *TheSection =
OutContext.getMachOSection("__IMPORT", "__jump_table",
MachO::S_SYMBOL_STUBS |
MachO::S_ATTR_SELF_MODIFYING_CODE |
MachO::S_ATTR_PURE_INSTRUCTIONS,
5, SectionKind::getMetadata());
OutStreamer.SwitchSection(TheSection);
for (const auto &Stub : Stubs) {
// L_foo$stub:
OutStreamer.EmitLabel(Stub.first);
// .indirect_symbol _foo
OutStreamer.EmitSymbolAttribute(Stub.second.getPointer(),
MCSA_IndirectSymbol);
// hlt; hlt; hlt; hlt; hlt hlt = 0xf4.
const char HltInsts[] = "\xf4\xf4\xf4\xf4\xf4";
OutStreamer.EmitBytes(StringRef(HltInsts, 5));
}
Stubs.clear();
OutStreamer.AddBlankLine();
}
// Output stubs for external and common global variables.
Stubs = MMIMacho.GetGVStubList();
if (!Stubs.empty()) {
const MCSection *TheSection =
OutContext.getMachOSection("__IMPORT", "__pointers",
MachO::S_NON_LAZY_SYMBOL_POINTERS,
SectionKind::getMetadata());
OutStreamer.SwitchSection(TheSection);
for (auto &Stub : Stubs)
emitNonLazySymbolPointer(OutStreamer, Stub.first, Stub.second);
Stubs.clear();
OutStreamer.AddBlankLine();
}
Stubs = MMIMacho.GetHiddenGVStubList();
if (!Stubs.empty()) {
const MCSection *TheSection =
OutContext.getMachOSection("__IMPORT", "__pointers",
MachO::S_NON_LAZY_SYMBOL_POINTERS,
SectionKind::getMetadata());
OutStreamer.SwitchSection(TheSection);
for (auto &Stub : Stubs)
emitNonLazySymbolPointer(OutStreamer, Stub.first, Stub.second);
Stubs.clear();
OutStreamer.AddBlankLine();
}
SM.serializeToStackMapSection();
// Funny Darwin hack: This flag tells the linker that no global symbols
// contain code that falls through to other global symbols (e.g. the obvious
// 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);
}
if (Subtarget->isTargetKnownWindowsMSVC() && MMI->usesVAFloatArgument()) {
StringRef SymbolName = Subtarget->is64Bit() ? "_fltused" : "__fltused";
MCSymbol *S = MMI->getContext().GetOrCreateSymbol(SymbolName);
OutStreamer.EmitSymbolAttribute(S, MCSA_Global);
}
if (Subtarget->isTargetCOFF()) {
// Necessary for dllexport support
std::vector<const MCSymbol*> DLLExportedFns, DLLExportedGlobals;
for (const auto &Function : M)
if (Function.hasDLLExportStorageClass())
DLLExportedFns.push_back(getSymbol(&Function));
for (const auto &Global : M.globals())
if (Global.hasDLLExportStorageClass())
DLLExportedGlobals.push_back(getSymbol(&Global));
for (const auto &Alias : M.aliases()) {
if (!Alias.hasDLLExportStorageClass())
continue;
if (Alias.getType()->getElementType()->isFunctionTy())
DLLExportedFns.push_back(getSymbol(&Alias));
else
DLLExportedGlobals.push_back(getSymbol(&Alias));
}
// Output linker support code for dllexported globals on windows.
if (!DLLExportedGlobals.empty() || !DLLExportedFns.empty()) {
const TargetLoweringObjectFileCOFF &TLOFCOFF =
static_cast<const TargetLoweringObjectFileCOFF&>(getObjFileLowering());
OutStreamer.SwitchSection(TLOFCOFF.getDrectveSection());
for (auto & Symbol : DLLExportedGlobals)
GenerateExportDirective(Symbol, /*IsData=*/true);
for (auto & Symbol : DLLExportedFns)
GenerateExportDirective(Symbol, /*IsData=*/false);
}
}
if (Subtarget->isTargetELF()) {
const TargetLoweringObjectFileELF &TLOFELF =
static_cast<const TargetLoweringObjectFileELF &>(getObjFileLowering());
MachineModuleInfoELF &MMIELF = MMI->getObjFileInfo<MachineModuleInfoELF>();
// Output stubs for external and common global variables.
MachineModuleInfoELF::SymbolListTy Stubs = MMIELF.GetGVStubList();
if (!Stubs.empty()) {
OutStreamer.SwitchSection(TLOFELF.getDataRelSection());
const DataLayout *TD = TM.getDataLayout();
for (const auto &Stub : Stubs) {
OutStreamer.EmitLabel(Stub.first);
OutStreamer.EmitSymbolValue(Stub.second.getPointer(),
TD->getPointerSize());
}
Stubs.clear();
}
}
}
//===----------------------------------------------------------------------===//
// Target Registry Stuff
//===----------------------------------------------------------------------===//
// Force static initialization.
extern "C" void LLVMInitializeX86AsmPrinter() {
RegisterAsmPrinter<X86AsmPrinter> X(TheX86_32Target);
RegisterAsmPrinter<X86AsmPrinter> Y(TheX86_64Target);
}
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