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llvm-mirror/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
Chris Lattner e2f110cba5 fix the definitions of ConstTextCoalSection/ConstDataCoalSection 
to keep "Text" in sync with the "pure instructions" section attribute.
Lack of this attribute was preventing the assembler from emitting
multibyte noops instructions for templates (and inlines, and other
coalesced stuff) and was causing the assembler to mismatch .o files.

This fixes rdar://8018335

llvm-svn: 108461
2010-07-15 21:22:00 +00:00

1011 lines
41 KiB
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Raw Blame History

//===-- llvm/CodeGen/TargetLoweringObjectFileImpl.cpp - Object File Info --===//
//
// 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.
//
//===----------------------------------------------------------------------===//
#include "llvm/CodeGen/TargetLoweringObjectFileImpl.h"
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Function.h"
#include "llvm/GlobalVariable.h"
#include "llvm/CodeGen/MachineModuleInfoImpls.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCSectionMachO.h"
#include "llvm/MC/MCSectionELF.h"
#include "llvm/MC/MCSectionCOFF.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/Target/Mangler.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/Support/Dwarf.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/StringExtras.h"
using namespace llvm;
using namespace dwarf;
//===----------------------------------------------------------------------===//
// ELF
//===----------------------------------------------------------------------===//
void TargetLoweringObjectFileELF::Initialize(MCContext &Ctx,
const TargetMachine &TM) {
TargetLoweringObjectFile::Initialize(Ctx, TM);
BSSSection =
getContext().getELFSection(".bss", MCSectionELF::SHT_NOBITS,
MCSectionELF::SHF_WRITE |MCSectionELF::SHF_ALLOC,
SectionKind::getBSS());
TextSection =
getContext().getELFSection(".text", MCSectionELF::SHT_PROGBITS,
MCSectionELF::SHF_EXECINSTR |
MCSectionELF::SHF_ALLOC,
SectionKind::getText());
DataSection =
getContext().getELFSection(".data", MCSectionELF::SHT_PROGBITS,
MCSectionELF::SHF_WRITE |MCSectionELF::SHF_ALLOC,
SectionKind::getDataRel());
ReadOnlySection =
getContext().getELFSection(".rodata", MCSectionELF::SHT_PROGBITS,
MCSectionELF::SHF_ALLOC,
SectionKind::getReadOnly());
TLSDataSection =
getContext().getELFSection(".tdata", MCSectionELF::SHT_PROGBITS,
MCSectionELF::SHF_ALLOC | MCSectionELF::SHF_TLS |
MCSectionELF::SHF_WRITE,
SectionKind::getThreadData());
TLSBSSSection =
getContext().getELFSection(".tbss", MCSectionELF::SHT_NOBITS,
MCSectionELF::SHF_ALLOC | MCSectionELF::SHF_TLS |
MCSectionELF::SHF_WRITE,
SectionKind::getThreadBSS());
DataRelSection =
getContext().getELFSection(".data.rel", MCSectionELF::SHT_PROGBITS,
MCSectionELF::SHF_ALLOC |MCSectionELF::SHF_WRITE,
SectionKind::getDataRel());
DataRelLocalSection =
getContext().getELFSection(".data.rel.local", MCSectionELF::SHT_PROGBITS,
MCSectionELF::SHF_ALLOC |MCSectionELF::SHF_WRITE,
SectionKind::getDataRelLocal());
DataRelROSection =
getContext().getELFSection(".data.rel.ro", MCSectionELF::SHT_PROGBITS,
MCSectionELF::SHF_ALLOC |MCSectionELF::SHF_WRITE,
SectionKind::getReadOnlyWithRel());
DataRelROLocalSection =
getContext().getELFSection(".data.rel.ro.local", MCSectionELF::SHT_PROGBITS,
MCSectionELF::SHF_ALLOC |MCSectionELF::SHF_WRITE,
SectionKind::getReadOnlyWithRelLocal());
MergeableConst4Section =
getContext().getELFSection(".rodata.cst4", MCSectionELF::SHT_PROGBITS,
MCSectionELF::SHF_ALLOC |MCSectionELF::SHF_MERGE,
SectionKind::getMergeableConst4());
MergeableConst8Section =
getContext().getELFSection(".rodata.cst8", MCSectionELF::SHT_PROGBITS,
MCSectionELF::SHF_ALLOC |MCSectionELF::SHF_MERGE,
SectionKind::getMergeableConst8());
MergeableConst16Section =
getContext().getELFSection(".rodata.cst16", MCSectionELF::SHT_PROGBITS,
MCSectionELF::SHF_ALLOC |MCSectionELF::SHF_MERGE,
SectionKind::getMergeableConst16());
StaticCtorSection =
getContext().getELFSection(".ctors", MCSectionELF::SHT_PROGBITS,
MCSectionELF::SHF_ALLOC |MCSectionELF::SHF_WRITE,
SectionKind::getDataRel());
StaticDtorSection =
getContext().getELFSection(".dtors", MCSectionELF::SHT_PROGBITS,
MCSectionELF::SHF_ALLOC |MCSectionELF::SHF_WRITE,
SectionKind::getDataRel());
// Exception Handling Sections.
// FIXME: We're emitting LSDA info into a readonly section on ELF, even though
// it contains relocatable pointers. In PIC mode, this is probably a big
// runtime hit for C++ apps. Either the contents of the LSDA need to be
// adjusted or this should be a data section.
LSDASection =
getContext().getELFSection(".gcc_except_table", MCSectionELF::SHT_PROGBITS,
MCSectionELF::SHF_ALLOC,
SectionKind::getReadOnly());
EHFrameSection =
getContext().getELFSection(".eh_frame", MCSectionELF::SHT_PROGBITS,
MCSectionELF::SHF_ALLOC |MCSectionELF::SHF_WRITE,
SectionKind::getDataRel());
// Debug Info Sections.
DwarfAbbrevSection =
getContext().getELFSection(".debug_abbrev", MCSectionELF::SHT_PROGBITS, 0,
SectionKind::getMetadata());
DwarfInfoSection =
getContext().getELFSection(".debug_info", MCSectionELF::SHT_PROGBITS, 0,
SectionKind::getMetadata());
DwarfLineSection =
getContext().getELFSection(".debug_line", MCSectionELF::SHT_PROGBITS, 0,
SectionKind::getMetadata());
DwarfFrameSection =
getContext().getELFSection(".debug_frame", MCSectionELF::SHT_PROGBITS, 0,
SectionKind::getMetadata());
DwarfPubNamesSection =
getContext().getELFSection(".debug_pubnames", MCSectionELF::SHT_PROGBITS, 0,
SectionKind::getMetadata());
DwarfPubTypesSection =
getContext().getELFSection(".debug_pubtypes", MCSectionELF::SHT_PROGBITS, 0,
SectionKind::getMetadata());
DwarfStrSection =
getContext().getELFSection(".debug_str", MCSectionELF::SHT_PROGBITS, 0,
SectionKind::getMetadata());
DwarfLocSection =
getContext().getELFSection(".debug_loc", MCSectionELF::SHT_PROGBITS, 0,
SectionKind::getMetadata());
DwarfARangesSection =
getContext().getELFSection(".debug_aranges", MCSectionELF::SHT_PROGBITS, 0,
SectionKind::getMetadata());
DwarfRangesSection =
getContext().getELFSection(".debug_ranges", MCSectionELF::SHT_PROGBITS, 0,
SectionKind::getMetadata());
DwarfMacroInfoSection =
getContext().getELFSection(".debug_macinfo", MCSectionELF::SHT_PROGBITS, 0,
SectionKind::getMetadata());
}
static SectionKind
getELFKindForNamedSection(StringRef Name, SectionKind K) {
if (Name.empty() || Name[0] != '.') return K;
// Some lame default implementation based on some magic section names.
if (Name == ".bss" ||
Name.startswith(".bss.") ||
Name.startswith(".gnu.linkonce.b.") ||
Name.startswith(".llvm.linkonce.b.") ||
Name == ".sbss" ||
Name.startswith(".sbss.") ||
Name.startswith(".gnu.linkonce.sb.") ||
Name.startswith(".llvm.linkonce.sb."))
return SectionKind::getBSS();
if (Name == ".tdata" ||
Name.startswith(".tdata.") ||
Name.startswith(".gnu.linkonce.td.") ||
Name.startswith(".llvm.linkonce.td."))
return SectionKind::getThreadData();
if (Name == ".tbss" ||
Name.startswith(".tbss.") ||
Name.startswith(".gnu.linkonce.tb.") ||
Name.startswith(".llvm.linkonce.tb."))
return SectionKind::getThreadBSS();
return K;
}
static unsigned getELFSectionType(StringRef Name, SectionKind K) {
if (Name == ".init_array")
return MCSectionELF::SHT_INIT_ARRAY;
if (Name == ".fini_array")
return MCSectionELF::SHT_FINI_ARRAY;
if (Name == ".preinit_array")
return MCSectionELF::SHT_PREINIT_ARRAY;
if (K.isBSS() || K.isThreadBSS())
return MCSectionELF::SHT_NOBITS;
return MCSectionELF::SHT_PROGBITS;
}
static unsigned
getELFSectionFlags(SectionKind K) {
unsigned Flags = 0;
if (!K.isMetadata())
Flags |= MCSectionELF::SHF_ALLOC;
if (K.isText())
Flags |= MCSectionELF::SHF_EXECINSTR;
if (K.isWriteable())
Flags |= MCSectionELF::SHF_WRITE;
if (K.isThreadLocal())
Flags |= MCSectionELF::SHF_TLS;
// K.isMergeableConst() is left out to honour PR4650
if (K.isMergeableCString() || K.isMergeableConst4() ||
K.isMergeableConst8() || K.isMergeableConst16())
Flags |= MCSectionELF::SHF_MERGE;
if (K.isMergeableCString())
Flags |= MCSectionELF::SHF_STRINGS;
return Flags;
}
const MCSection *TargetLoweringObjectFileELF::
getExplicitSectionGlobal(const GlobalValue *GV, SectionKind Kind,
Mangler *Mang, const TargetMachine &TM) const {
StringRef SectionName = GV->getSection();
// Infer section flags from the section name if we can.
Kind = getELFKindForNamedSection(SectionName, Kind);
return getContext().getELFSection(SectionName,
getELFSectionType(SectionName, Kind),
getELFSectionFlags(Kind), Kind, true);
}
static const char *getSectionPrefixForUniqueGlobal(SectionKind Kind) {
if (Kind.isText()) return ".gnu.linkonce.t.";
if (Kind.isReadOnly()) return ".gnu.linkonce.r.";
if (Kind.isThreadData()) return ".gnu.linkonce.td.";
if (Kind.isThreadBSS()) return ".gnu.linkonce.tb.";
if (Kind.isDataNoRel()) return ".gnu.linkonce.d.";
if (Kind.isDataRelLocal()) return ".gnu.linkonce.d.rel.local.";
if (Kind.isDataRel()) return ".gnu.linkonce.d.rel.";
if (Kind.isReadOnlyWithRelLocal()) return ".gnu.linkonce.d.rel.ro.local.";
assert(Kind.isReadOnlyWithRel() && "Unknown section kind");
return ".gnu.linkonce.d.rel.ro.";
}
/// getSectionPrefixForGlobal - Return the section prefix name used by options
/// FunctionsSections and DataSections.
static const char *getSectionPrefixForGlobal(SectionKind Kind) {
if (Kind.isText()) return ".text.";
if (Kind.isReadOnly()) return ".rodata.";
if (Kind.isThreadData()) return ".tdata.";
if (Kind.isThreadBSS()) return ".tbss.";
if (Kind.isDataNoRel()) return ".data.";
if (Kind.isDataRelLocal()) return ".data.rel.local.";
if (Kind.isDataRel()) return ".data.rel.";
if (Kind.isReadOnlyWithRelLocal()) return ".data.rel.ro.local.";
assert(Kind.isReadOnlyWithRel() && "Unknown section kind");
return ".data.rel.ro.";
}
const MCSection *TargetLoweringObjectFileELF::
SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
Mangler *Mang, const TargetMachine &TM) const {
// If we have -ffunction-section or -fdata-section then we should emit the
// global value to a uniqued section specifically for it.
bool EmitUniquedSection;
if (Kind.isText())
EmitUniquedSection = TM.getFunctionSections();
else
EmitUniquedSection = TM.getDataSections();
// If this global is linkonce/weak and the target handles this by emitting it
// into a 'uniqued' section name, create and return the section now.
if ((GV->isWeakForLinker() || EmitUniquedSection) &&
!Kind.isCommon() && !Kind.isBSS()) {
const char *Prefix;
if (GV->isWeakForLinker())
Prefix = getSectionPrefixForUniqueGlobal(Kind);
else {
assert(EmitUniquedSection);
Prefix = getSectionPrefixForGlobal(Kind);
}
SmallString<128> Name(Prefix, Prefix+strlen(Prefix));
MCSymbol *Sym = Mang->getSymbol(GV);
Name.append(Sym->getName().begin(), Sym->getName().end());
return getContext().getELFSection(Name.str(),
getELFSectionType(Name.str(), Kind),
getELFSectionFlags(Kind), Kind);
}
if (Kind.isText()) return TextSection;
if (Kind.isMergeable1ByteCString() ||
Kind.isMergeable2ByteCString() ||
Kind.isMergeable4ByteCString()) {
// We also need alignment here.
// FIXME: this is getting the alignment of the character, not the
// alignment of the global!
unsigned Align =
TM.getTargetData()->getPreferredAlignment(cast<GlobalVariable>(GV));
const char *SizeSpec = ".rodata.str1.";
if (Kind.isMergeable2ByteCString())
SizeSpec = ".rodata.str2.";
else if (Kind.isMergeable4ByteCString())
SizeSpec = ".rodata.str4.";
else
assert(Kind.isMergeable1ByteCString() && "unknown string width");
std::string Name = SizeSpec + utostr(Align);
return getContext().getELFSection(Name, MCSectionELF::SHT_PROGBITS,
MCSectionELF::SHF_ALLOC |
MCSectionELF::SHF_MERGE |
MCSectionELF::SHF_STRINGS,
Kind);
}
if (Kind.isMergeableConst()) {
if (Kind.isMergeableConst4() && MergeableConst4Section)
return MergeableConst4Section;
if (Kind.isMergeableConst8() && MergeableConst8Section)
return MergeableConst8Section;
if (Kind.isMergeableConst16() && MergeableConst16Section)
return MergeableConst16Section;
return ReadOnlySection; // .const
}
if (Kind.isReadOnly()) return ReadOnlySection;
if (Kind.isThreadData()) return TLSDataSection;
if (Kind.isThreadBSS()) return TLSBSSSection;
// Note: we claim that common symbols are put in BSSSection, but they are
// really emitted with the magic .comm directive, which creates a symbol table
// entry but not a section.
if (Kind.isBSS() || Kind.isCommon()) return BSSSection;
if (Kind.isDataNoRel()) return DataSection;
if (Kind.isDataRelLocal()) return DataRelLocalSection;
if (Kind.isDataRel()) return DataRelSection;
if (Kind.isReadOnlyWithRelLocal()) return DataRelROLocalSection;
assert(Kind.isReadOnlyWithRel() && "Unknown section kind");
return DataRelROSection;
}
/// getSectionForConstant - Given a mergeable constant with the
/// specified size and relocation information, return a section that it
/// should be placed in.
const MCSection *TargetLoweringObjectFileELF::
getSectionForConstant(SectionKind Kind) const {
if (Kind.isMergeableConst4() && MergeableConst4Section)
return MergeableConst4Section;
if (Kind.isMergeableConst8() && MergeableConst8Section)
return MergeableConst8Section;
if (Kind.isMergeableConst16() && MergeableConst16Section)
return MergeableConst16Section;
if (Kind.isReadOnly())
return ReadOnlySection;
if (Kind.isReadOnlyWithRelLocal()) return DataRelROLocalSection;
assert(Kind.isReadOnlyWithRel() && "Unknown section kind");
return DataRelROSection;
}
const MCExpr *TargetLoweringObjectFileELF::
getExprForDwarfGlobalReference(const GlobalValue *GV, Mangler *Mang,
MachineModuleInfo *MMI,
unsigned Encoding, MCStreamer &Streamer) const {
if (Encoding & dwarf::DW_EH_PE_indirect) {
MachineModuleInfoELF &ELFMMI = MMI->getObjFileInfo<MachineModuleInfoELF>();
SmallString<128> Name;
Mang->getNameWithPrefix(Name, GV, true);
Name += ".DW.stub";
// Add information about the stub reference to ELFMMI so that the stub
// gets emitted by the asmprinter.
MCSymbol *SSym = getContext().GetOrCreateSymbol(Name.str());
MachineModuleInfoImpl::StubValueTy &StubSym = ELFMMI.getGVStubEntry(SSym);
if (StubSym.getPointer() == 0) {
MCSymbol *Sym = Mang->getSymbol(GV);
StubSym = MachineModuleInfoImpl::StubValueTy(Sym, !GV->hasLocalLinkage());
}
return TargetLoweringObjectFile::
getExprForDwarfReference(SSym, Mang, MMI,
Encoding & ~dwarf::DW_EH_PE_indirect, Streamer);
}
return TargetLoweringObjectFile::
getExprForDwarfGlobalReference(GV, Mang, MMI, Encoding, Streamer);
}
//===----------------------------------------------------------------------===//
// MachO
//===----------------------------------------------------------------------===//
void TargetLoweringObjectFileMachO::Initialize(MCContext &Ctx,
const TargetMachine &TM) {
// _foo.eh symbols are currently always exported so that the linker knows
// about them. This is not necessary on 10.6 and later, but it
// doesn't hurt anything.
// FIXME: I need to get this from Triple.
IsFunctionEHSymbolGlobal = true;
IsFunctionEHFrameSymbolPrivate = false;
SupportsWeakOmittedEHFrame = false;
TargetLoweringObjectFile::Initialize(Ctx, TM);
TextSection // .text
= getContext().getMachOSection("__TEXT", "__text",
MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS,
SectionKind::getText());
DataSection // .data
= getContext().getMachOSection("__DATA", "__data", 0,
SectionKind::getDataRel());
TLSDataSection // .tdata
= getContext().getMachOSection("__DATA", "__thread_data",
MCSectionMachO::S_THREAD_LOCAL_REGULAR,
SectionKind::getDataRel());
TLSBSSSection // .tbss
= getContext().getMachOSection("__DATA", "__thread_bss",
MCSectionMachO::S_THREAD_LOCAL_ZEROFILL,
SectionKind::getThreadBSS());
// TODO: Verify datarel below.
TLSTLVSection // .tlv
= getContext().getMachOSection("__DATA", "__thread_vars",
MCSectionMachO::S_THREAD_LOCAL_VARIABLES,
SectionKind::getDataRel());
TLSThreadInitSection
= getContext().getMachOSection("__DATA", "__thread_init",
MCSectionMachO::S_THREAD_LOCAL_INIT_FUNCTION_POINTERS,
SectionKind::getDataRel());
CStringSection // .cstring
= getContext().getMachOSection("__TEXT", "__cstring",
MCSectionMachO::S_CSTRING_LITERALS,
SectionKind::getMergeable1ByteCString());
UStringSection
= getContext().getMachOSection("__TEXT","__ustring", 0,
SectionKind::getMergeable2ByteCString());
FourByteConstantSection // .literal4
= getContext().getMachOSection("__TEXT", "__literal4",
MCSectionMachO::S_4BYTE_LITERALS,
SectionKind::getMergeableConst4());
EightByteConstantSection // .literal8
= getContext().getMachOSection("__TEXT", "__literal8",
MCSectionMachO::S_8BYTE_LITERALS,
SectionKind::getMergeableConst8());
// ld_classic doesn't support .literal16 in 32-bit mode, and ld64 falls back
// to using it in -static mode.
SixteenByteConstantSection = 0;
if (TM.getRelocationModel() != Reloc::Static &&
TM.getTargetData()->getPointerSize() == 32)
SixteenByteConstantSection = // .literal16
getContext().getMachOSection("__TEXT", "__literal16",
MCSectionMachO::S_16BYTE_LITERALS,
SectionKind::getMergeableConst16());
ReadOnlySection // .const
= getContext().getMachOSection("__TEXT", "__const", 0,
SectionKind::getReadOnly());
TextCoalSection
= getContext().getMachOSection("__TEXT", "__textcoal_nt",
MCSectionMachO::S_COALESCED |
MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS,
SectionKind::getText());
ConstTextCoalSection
= getContext().getMachOSection("__TEXT", "__const_coal",
MCSectionMachO::S_COALESCED |
MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS,
SectionKind::getText());
ConstDataCoalSection
= getContext().getMachOSection("__DATA","__const_coal",
MCSectionMachO::S_COALESCED,
SectionKind::getReadOnly());
ConstDataSection // .const_data
= getContext().getMachOSection("__DATA", "__const", 0,
SectionKind::getReadOnlyWithRel());
DataCoalSection
= getContext().getMachOSection("__DATA","__datacoal_nt",
MCSectionMachO::S_COALESCED,
SectionKind::getDataRel());
DataCommonSection
= getContext().getMachOSection("__DATA","__common",
MCSectionMachO::S_ZEROFILL,
SectionKind::getBSS());
DataBSSSection
= getContext().getMachOSection("__DATA","__bss", MCSectionMachO::S_ZEROFILL,
SectionKind::getBSS());
LazySymbolPointerSection
= getContext().getMachOSection("__DATA", "__la_symbol_ptr",
MCSectionMachO::S_LAZY_SYMBOL_POINTERS,
SectionKind::getMetadata());
NonLazySymbolPointerSection
= getContext().getMachOSection("__DATA", "__nl_symbol_ptr",
MCSectionMachO::S_NON_LAZY_SYMBOL_POINTERS,
SectionKind::getMetadata());
if (TM.getRelocationModel() == Reloc::Static) {
StaticCtorSection
= getContext().getMachOSection("__TEXT", "__constructor", 0,
SectionKind::getDataRel());
StaticDtorSection
= getContext().getMachOSection("__TEXT", "__destructor", 0,
SectionKind::getDataRel());
} else {
StaticCtorSection
= getContext().getMachOSection("__DATA", "__mod_init_func",
MCSectionMachO::S_MOD_INIT_FUNC_POINTERS,
SectionKind::getDataRel());
StaticDtorSection
= getContext().getMachOSection("__DATA", "__mod_term_func",
MCSectionMachO::S_MOD_TERM_FUNC_POINTERS,
SectionKind::getDataRel());
}
// Exception Handling.
LSDASection = getContext().getMachOSection("__TEXT", "__gcc_except_tab", 0,
SectionKind::getReadOnlyWithRel());
EHFrameSection =
getContext().getMachOSection("__TEXT", "__eh_frame",
MCSectionMachO::S_COALESCED |
MCSectionMachO::S_ATTR_NO_TOC |
MCSectionMachO::S_ATTR_STRIP_STATIC_SYMS |
MCSectionMachO::S_ATTR_LIVE_SUPPORT,
SectionKind::getReadOnly());
// Debug Information.
DwarfAbbrevSection =
getContext().getMachOSection("__DWARF", "__debug_abbrev",
MCSectionMachO::S_ATTR_DEBUG,
SectionKind::getMetadata());
DwarfInfoSection =
getContext().getMachOSection("__DWARF", "__debug_info",
MCSectionMachO::S_ATTR_DEBUG,
SectionKind::getMetadata());
DwarfLineSection =
getContext().getMachOSection("__DWARF", "__debug_line",
MCSectionMachO::S_ATTR_DEBUG,
SectionKind::getMetadata());
DwarfFrameSection =
getContext().getMachOSection("__DWARF", "__debug_frame",
MCSectionMachO::S_ATTR_DEBUG,
SectionKind::getMetadata());
DwarfPubNamesSection =
getContext().getMachOSection("__DWARF", "__debug_pubnames",
MCSectionMachO::S_ATTR_DEBUG,
SectionKind::getMetadata());
DwarfPubTypesSection =
getContext().getMachOSection("__DWARF", "__debug_pubtypes",
MCSectionMachO::S_ATTR_DEBUG,
SectionKind::getMetadata());
DwarfStrSection =
getContext().getMachOSection("__DWARF", "__debug_str",
MCSectionMachO::S_ATTR_DEBUG,
SectionKind::getMetadata());
DwarfLocSection =
getContext().getMachOSection("__DWARF", "__debug_loc",
MCSectionMachO::S_ATTR_DEBUG,
SectionKind::getMetadata());
DwarfARangesSection =
getContext().getMachOSection("__DWARF", "__debug_aranges",
MCSectionMachO::S_ATTR_DEBUG,
SectionKind::getMetadata());
DwarfRangesSection =
getContext().getMachOSection("__DWARF", "__debug_ranges",
MCSectionMachO::S_ATTR_DEBUG,
SectionKind::getMetadata());
DwarfMacroInfoSection =
getContext().getMachOSection("__DWARF", "__debug_macinfo",
MCSectionMachO::S_ATTR_DEBUG,
SectionKind::getMetadata());
DwarfDebugInlineSection =
getContext().getMachOSection("__DWARF", "__debug_inlined",
MCSectionMachO::S_ATTR_DEBUG,
SectionKind::getMetadata());
TLSExtraDataSection = TLSTLVSection;
}
const MCSection *TargetLoweringObjectFileMachO::
getExplicitSectionGlobal(const GlobalValue *GV, SectionKind Kind,
Mangler *Mang, const TargetMachine &TM) const {
// Parse the section specifier and create it if valid.
StringRef Segment, Section;
unsigned TAA, StubSize;
std::string ErrorCode =
MCSectionMachO::ParseSectionSpecifier(GV->getSection(), Segment, Section,
TAA, StubSize);
if (!ErrorCode.empty()) {
// If invalid, report the error with report_fatal_error.
report_fatal_error("Global variable '" + GV->getNameStr() +
"' has an invalid section specifier '" + GV->getSection()+
"': " + ErrorCode + ".");
// Fall back to dropping it into the data section.
return DataSection;
}
// Get the section.
const MCSectionMachO *S =
getContext().getMachOSection(Segment, Section, TAA, StubSize, Kind);
// Okay, now that we got the section, verify that the TAA & StubSize agree.
// If the user declared multiple globals with different section flags, we need
// to reject it here.
if (S->getTypeAndAttributes() != TAA || S->getStubSize() != StubSize) {
// If invalid, report the error with report_fatal_error.
report_fatal_error("Global variable '" + GV->getNameStr() +
"' section type or attributes does not match previous"
" section specifier");
}
return S;
}
const MCSection *TargetLoweringObjectFileMachO::
SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
Mangler *Mang, const TargetMachine &TM) const {
// Handle thread local data.
if (Kind.isThreadBSS()) return TLSBSSSection;
if (Kind.isThreadData()) return TLSDataSection;
if (Kind.isText())
return GV->isWeakForLinker() ? TextCoalSection : TextSection;
// If this is weak/linkonce, put this in a coalescable section, either in text
// or data depending on if it is writable.
if (GV->isWeakForLinker()) {
if (Kind.isReadOnly())
return ConstTextCoalSection;
return DataCoalSection;
}
// FIXME: Alignment check should be handled by section classifier.
if (Kind.isMergeable1ByteCString() &&
TM.getTargetData()->getPreferredAlignment(cast<GlobalVariable>(GV)) < 32)
return CStringSection;
// Do not put 16-bit arrays in the UString section if they have an
// externally visible label, this runs into issues with certain linker
// versions.
if (Kind.isMergeable2ByteCString() && !GV->hasExternalLinkage() &&
TM.getTargetData()->getPreferredAlignment(cast<GlobalVariable>(GV)) < 32)
return UStringSection;
if (Kind.isMergeableConst()) {
if (Kind.isMergeableConst4())
return FourByteConstantSection;
if (Kind.isMergeableConst8())
return EightByteConstantSection;
if (Kind.isMergeableConst16() && SixteenByteConstantSection)
return SixteenByteConstantSection;
}
// Otherwise, if it is readonly, but not something we can specially optimize,
// just drop it in .const.
if (Kind.isReadOnly())
return ReadOnlySection;
// If this is marked const, put it into a const section. But if the dynamic
// linker needs to write to it, put it in the data segment.
if (Kind.isReadOnlyWithRel())
return ConstDataSection;
// Put zero initialized globals with strong external linkage in the
// DATA, __common section with the .zerofill directive.
if (Kind.isBSSExtern())
return DataCommonSection;
// Put zero initialized globals with local linkage in __DATA,__bss directive
// with the .zerofill directive (aka .lcomm).
if (Kind.isBSSLocal())
return DataBSSSection;
// Otherwise, just drop the variable in the normal data section.
return DataSection;
}
const MCSection *
TargetLoweringObjectFileMachO::getSectionForConstant(SectionKind Kind) const {
// If this constant requires a relocation, we have to put it in the data
// segment, not in the text segment.
if (Kind.isDataRel() || Kind.isReadOnlyWithRel())
return ConstDataSection;
if (Kind.isMergeableConst4())
return FourByteConstantSection;
if (Kind.isMergeableConst8())
return EightByteConstantSection;
if (Kind.isMergeableConst16() && SixteenByteConstantSection)
return SixteenByteConstantSection;
return ReadOnlySection; // .const
}
/// shouldEmitUsedDirectiveFor - This hook allows targets to selectively decide
/// not to emit the UsedDirective for some symbols in llvm.used.
// FIXME: REMOVE this (rdar://7071300)
bool TargetLoweringObjectFileMachO::
shouldEmitUsedDirectiveFor(const GlobalValue *GV, Mangler *Mang) const {
/// On Darwin, internally linked data beginning with "L" or "l" does not have
/// the directive emitted (this occurs in ObjC metadata).
if (!GV) return false;
// Check whether the mangled name has the "Private" or "LinkerPrivate" prefix.
if (GV->hasLocalLinkage() && !isa<Function>(GV)) {
// FIXME: ObjC metadata is currently emitted as internal symbols that have
// \1L and \0l prefixes on them. Fix them to be Private/LinkerPrivate and
// this horrible hack can go away.
MCSymbol *Sym = Mang->getSymbol(GV);
if (Sym->getName()[0] == 'L' || Sym->getName()[0] == 'l')
return false;
}
return true;
}
const MCExpr *TargetLoweringObjectFileMachO::
getExprForDwarfGlobalReference(const GlobalValue *GV, Mangler *Mang,
MachineModuleInfo *MMI, unsigned Encoding,
MCStreamer &Streamer) const {
// The mach-o version of this method defaults to returning a stub reference.
if (Encoding & DW_EH_PE_indirect) {
MachineModuleInfoMachO &MachOMMI =
MMI->getObjFileInfo<MachineModuleInfoMachO>();
SmallString<128> Name;
Mang->getNameWithPrefix(Name, GV, true);
Name += "$non_lazy_ptr";
// Add information about the stub reference to MachOMMI so that the stub
// gets emitted by the asmprinter.
MCSymbol *SSym = getContext().GetOrCreateSymbol(Name.str());
MachineModuleInfoImpl::StubValueTy &StubSym = MachOMMI.getGVStubEntry(SSym);
if (StubSym.getPointer() == 0) {
MCSymbol *Sym = Mang->getSymbol(GV);
StubSym = MachineModuleInfoImpl::StubValueTy(Sym, !GV->hasLocalLinkage());
}
return TargetLoweringObjectFile::
getExprForDwarfReference(SSym, Mang, MMI,
Encoding & ~dwarf::DW_EH_PE_indirect, Streamer);
}
return TargetLoweringObjectFile::
getExprForDwarfGlobalReference(GV, Mang, MMI, Encoding, Streamer);
}
unsigned TargetLoweringObjectFileMachO::getPersonalityEncoding() const {
return DW_EH_PE_indirect | DW_EH_PE_pcrel | DW_EH_PE_sdata4;
}
unsigned TargetLoweringObjectFileMachO::getLSDAEncoding() const {
return DW_EH_PE_pcrel;
}
unsigned TargetLoweringObjectFileMachO::getFDEEncoding() const {
return DW_EH_PE_pcrel;
}
unsigned TargetLoweringObjectFileMachO::getTTypeEncoding() const {
return DW_EH_PE_indirect | DW_EH_PE_pcrel | DW_EH_PE_sdata4;
}
//===----------------------------------------------------------------------===//
// COFF
//===----------------------------------------------------------------------===//
void TargetLoweringObjectFileCOFF::Initialize(MCContext &Ctx,
const TargetMachine &TM) {
TargetLoweringObjectFile::Initialize(Ctx, TM);
TextSection =
getContext().getCOFFSection(".text",
COFF::IMAGE_SCN_CNT_CODE |
COFF::IMAGE_SCN_MEM_EXECUTE |
COFF::IMAGE_SCN_MEM_READ,
SectionKind::getText());
DataSection =
getContext().getCOFFSection(".data",
COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ |
COFF::IMAGE_SCN_MEM_WRITE,
SectionKind::getDataRel());
ReadOnlySection =
getContext().getCOFFSection(".rdata",
COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ,
SectionKind::getReadOnly());
StaticCtorSection =
getContext().getCOFFSection(".ctors",
COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ |
COFF::IMAGE_SCN_MEM_WRITE,
SectionKind::getDataRel());
StaticDtorSection =
getContext().getCOFFSection(".dtors",
COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ |
COFF::IMAGE_SCN_MEM_WRITE,
SectionKind::getDataRel());
// FIXME: We're emitting LSDA info into a readonly section on COFF, even
// though it contains relocatable pointers. In PIC mode, this is probably a
// big runtime hit for C++ apps. Either the contents of the LSDA need to be
// adjusted or this should be a data section.
LSDASection =
getContext().getCOFFSection(".gcc_except_table",
COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ,
SectionKind::getReadOnly());
EHFrameSection =
getContext().getCOFFSection(".eh_frame",
COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ |
COFF::IMAGE_SCN_MEM_WRITE,
SectionKind::getDataRel());
// Debug info.
DwarfAbbrevSection =
getContext().getCOFFSection(".debug_abbrev",
COFF::IMAGE_SCN_MEM_DISCARDABLE |
COFF::IMAGE_SCN_MEM_READ,
SectionKind::getMetadata());
DwarfInfoSection =
getContext().getCOFFSection(".debug_info",
COFF::IMAGE_SCN_MEM_DISCARDABLE |
COFF::IMAGE_SCN_MEM_READ,
SectionKind::getMetadata());
DwarfLineSection =
getContext().getCOFFSection(".debug_line",
COFF::IMAGE_SCN_MEM_DISCARDABLE |
COFF::IMAGE_SCN_MEM_READ,
SectionKind::getMetadata());
DwarfFrameSection =
getContext().getCOFFSection(".debug_frame",
COFF::IMAGE_SCN_MEM_DISCARDABLE |
COFF::IMAGE_SCN_MEM_READ,
SectionKind::getMetadata());
DwarfPubNamesSection =
getContext().getCOFFSection(".debug_pubnames",
COFF::IMAGE_SCN_MEM_DISCARDABLE |
COFF::IMAGE_SCN_MEM_READ,
SectionKind::getMetadata());
DwarfPubTypesSection =
getContext().getCOFFSection(".debug_pubtypes",
COFF::IMAGE_SCN_MEM_DISCARDABLE |
COFF::IMAGE_SCN_MEM_READ,
SectionKind::getMetadata());
DwarfStrSection =
getContext().getCOFFSection(".debug_str",
COFF::IMAGE_SCN_MEM_DISCARDABLE |
COFF::IMAGE_SCN_MEM_READ,
SectionKind::getMetadata());
DwarfLocSection =
getContext().getCOFFSection(".debug_loc",
COFF::IMAGE_SCN_MEM_DISCARDABLE |
COFF::IMAGE_SCN_MEM_READ,
SectionKind::getMetadata());
DwarfARangesSection =
getContext().getCOFFSection(".debug_aranges",
COFF::IMAGE_SCN_MEM_DISCARDABLE |
COFF::IMAGE_SCN_MEM_READ,
SectionKind::getMetadata());
DwarfRangesSection =
getContext().getCOFFSection(".debug_ranges",
COFF::IMAGE_SCN_MEM_DISCARDABLE |
COFF::IMAGE_SCN_MEM_READ,
SectionKind::getMetadata());
DwarfMacroInfoSection =
getContext().getCOFFSection(".debug_macinfo",
COFF::IMAGE_SCN_MEM_DISCARDABLE |
COFF::IMAGE_SCN_MEM_READ,
SectionKind::getMetadata());
DrectveSection =
getContext().getCOFFSection(".drectve",
COFF::IMAGE_SCN_LNK_INFO,
SectionKind::getMetadata());
}
static unsigned
getCOFFSectionFlags(SectionKind K) {
unsigned Flags = 0;
if (K.isMetadata())
Flags |=
COFF::IMAGE_SCN_MEM_DISCARDABLE;
else if (K.isText())
Flags |=
COFF::IMAGE_SCN_MEM_EXECUTE |
COFF::IMAGE_SCN_CNT_CODE;
else if (K.isBSS ())
Flags |=
COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ |
COFF::IMAGE_SCN_MEM_WRITE;
else if (K.isReadOnly())
Flags |=
COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ;
else if (K.isWriteable())
Flags |=
COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
COFF::IMAGE_SCN_MEM_READ |
COFF::IMAGE_SCN_MEM_WRITE;
return Flags;
}
const MCSection *TargetLoweringObjectFileCOFF::
getExplicitSectionGlobal(const GlobalValue *GV, SectionKind Kind,
Mangler *Mang, const TargetMachine &TM) const {
return getContext().getCOFFSection(GV->getSection(),
getCOFFSectionFlags(Kind),
Kind);
}
static const char *getCOFFSectionPrefixForUniqueGlobal(SectionKind Kind) {
if (Kind.isText())
return ".text$linkonce";
if (Kind.isBSS ())
return ".bss$linkonce";
if (Kind.isWriteable())
return ".data$linkonce";
return ".rdata$linkonce";
}
const MCSection *TargetLoweringObjectFileCOFF::
SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
Mangler *Mang, const TargetMachine &TM) const {
assert(!Kind.isThreadLocal() && "Doesn't support TLS");
// If this global is linkonce/weak and the target handles this by emitting it
// into a 'uniqued' section name, create and return the section now.
if (GV->isWeakForLinker()) {
const char *Prefix = getCOFFSectionPrefixForUniqueGlobal(Kind);
SmallString<128> Name(Prefix, Prefix+strlen(Prefix));
MCSymbol *Sym = Mang->getSymbol(GV);
Name.append(Sym->getName().begin(), Sym->getName().end());
unsigned Characteristics = getCOFFSectionFlags(Kind);
Characteristics |= COFF::IMAGE_SCN_LNK_COMDAT;
return getContext().getCOFFSection(Name.str(), Characteristics,
COFF::IMAGE_COMDAT_SELECT_EXACT_MATCH, Kind);
}
if (Kind.isText())
return getTextSection();
return getDataSection();
}
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