llvm-6502/include/llvm/CodeGen/TargetLoweringObjectFileImpl.h
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

155 lines
6.0 KiB
C++

//==-- llvm/CodeGen/TargetLoweringObjectFileImpl.h - Object Info -*- C++ -*-==//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements classes used to handle lowerings specific to common
// object file formats.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_CODEGEN_TARGETLOWERINGOBJECTFILEIMPL_H
#define LLVM_CODEGEN_TARGETLOWERINGOBJECTFILEIMPL_H
#include "llvm/ADT/StringRef.h"
#include "llvm/MC/SectionKind.h"
#include "llvm/Target/TargetLoweringObjectFile.h"
namespace llvm {
class MachineModuleInfo;
class Mangler;
class MCAsmInfo;
class MCExpr;
class MCSection;
class MCSectionMachO;
class MCSymbol;
class MCContext;
class GlobalValue;
class TargetMachine;
class TargetLoweringObjectFileELF : public TargetLoweringObjectFile {
bool UseInitArray;
public:
virtual ~TargetLoweringObjectFileELF() {}
void emitPersonalityValue(MCStreamer &Streamer, const TargetMachine &TM,
const MCSymbol *Sym) const override;
/// Given a constant with the SectionKind, return a section that it should be
/// placed in.
const MCSection *getSectionForConstant(SectionKind Kind,
const Constant *C) const override;
const MCSection *getExplicitSectionGlobal(const GlobalValue *GV,
SectionKind Kind, Mangler &Mang,
const TargetMachine &TM) const override;
const MCSection *SelectSectionForGlobal(const GlobalValue *GV,
SectionKind Kind, Mangler &Mang,
const TargetMachine &TM) const override;
/// Return an MCExpr to use for a reference to the specified type info global
/// variable from exception handling information.
const MCExpr *
getTTypeGlobalReference(const GlobalValue *GV, unsigned Encoding,
Mangler &Mang, const TargetMachine &TM,
MachineModuleInfo *MMI,
MCStreamer &Streamer) const override;
// The symbol that gets passed to .cfi_personality.
MCSymbol *getCFIPersonalitySymbol(const GlobalValue *GV, Mangler &Mang,
const TargetMachine &TM,
MachineModuleInfo *MMI) const override;
void InitializeELF(bool UseInitArray_);
const MCSection *getStaticCtorSection(unsigned Priority,
const MCSymbol *KeySym) const override;
const MCSection *getStaticDtorSection(unsigned Priority,
const MCSymbol *KeySym) const override;
};
class TargetLoweringObjectFileMachO : public TargetLoweringObjectFile {
public:
virtual ~TargetLoweringObjectFileMachO() {}
/// Extract the dependent library name from a linker option string. Returns
/// StringRef() if the option does not specify a library.
StringRef getDepLibFromLinkerOpt(StringRef LinkerOption) const override;
/// Emit the module flags that specify the garbage collection information.
void emitModuleFlags(MCStreamer &Streamer,
ArrayRef<Module::ModuleFlagEntry> ModuleFlags,
Mangler &Mang, const TargetMachine &TM) const override;
bool isSectionAtomizableBySymbols(const MCSection &Section) const override;
const MCSection *
SelectSectionForGlobal(const GlobalValue *GV,
SectionKind Kind, Mangler &Mang,
const TargetMachine &TM) const override;
const MCSection *
getExplicitSectionGlobal(const GlobalValue *GV,
SectionKind Kind, Mangler &Mang,
const TargetMachine &TM) const override;
const MCSection *getSectionForConstant(SectionKind Kind,
const Constant *C) const override;
/// The mach-o version of this method defaults to returning a stub reference.
const MCExpr *
getTTypeGlobalReference(const GlobalValue *GV, unsigned Encoding,
Mangler &Mang, const TargetMachine &TM,
MachineModuleInfo *MMI,
MCStreamer &Streamer) const override;
// The symbol that gets passed to .cfi_personality.
MCSymbol *getCFIPersonalitySymbol(const GlobalValue *GV, Mangler &Mang,
const TargetMachine &TM,
MachineModuleInfo *MMI) const override;
};
class TargetLoweringObjectFileCOFF : public TargetLoweringObjectFile {
public:
virtual ~TargetLoweringObjectFileCOFF() {}
const MCSection *
getExplicitSectionGlobal(const GlobalValue *GV,
SectionKind Kind, Mangler &Mang,
const TargetMachine &TM) const override;
const MCSection *
SelectSectionForGlobal(const GlobalValue *GV,
SectionKind Kind, Mangler &Mang,
const TargetMachine &TM) const override;
/// Extract the dependent library name from a linker option string. Returns
/// StringRef() if the option does not specify a library.
StringRef getDepLibFromLinkerOpt(StringRef LinkerOption) const override;
/// Emit Obj-C garbage collection and linker options. Only linker option
/// emission is implemented for COFF.
void emitModuleFlags(MCStreamer &Streamer,
ArrayRef<Module::ModuleFlagEntry> ModuleFlags,
Mangler &Mang, const TargetMachine &TM) const override;
const MCSection *getStaticCtorSection(unsigned Priority,
const MCSymbol *KeySym) const override;
const MCSection *getStaticDtorSection(unsigned Priority,
const MCSymbol *KeySym) const override;
};
} // end namespace llvm
#endif