#include "llvm/MC/MCSectionMachO.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCSymbol.h"
+#include "llvm/MC/MCValue.h"
#include "llvm/Support/Dwarf.h"
#include "llvm/Support/ELF.h"
#include "llvm/Support/ErrorHandling.h"
return ELF::SHT_PROGBITS;
}
-
-static unsigned
-getELFSectionFlags(SectionKind K, bool InCOMDAT) {
+static unsigned getELFSectionFlags(SectionKind K) {
unsigned Flags = 0;
if (!K.isMetadata())
if (K.isThreadLocal())
Flags |= ELF::SHF_TLS;
- // FIXME: There is nothing in ELF preventing an SHF_MERGE from being
- // in a comdat. We just avoid it for now because we don't print
- // those .sections correctly.
- if (!InCOMDAT && (K.isMergeableCString() || K.isMergeableConst()))
+ if (K.isMergeableCString() || K.isMergeableConst())
Flags |= ELF::SHF_MERGE;
if (K.isMergeableCString())
Kind = getELFKindForNamedSection(SectionName, Kind);
StringRef Group = "";
- unsigned Flags = getELFSectionFlags(Kind, GV->hasComdat());
+ unsigned Flags = getELFSectionFlags(Kind);
if (const Comdat *C = getELFComdat(GV)) {
Group = C->getName();
Flags |= ELF::SHF_GROUP;
return ".data.rel.ro";
}
-const MCSection *TargetLoweringObjectFileELF::
-SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind,
- Mangler &Mang, const TargetMachine &TM) const {
- unsigned Flags = getELFSectionFlags(Kind, GV->hasComdat());
-
- // If we have -ffunction-section or -fdata-section then we should emit the
- // global value to a uniqued section specifically for it.
- bool EmitUniquedSection = false;
- if (!(Flags & ELF::SHF_MERGE) && !Kind.isCommon()) {
- if (Kind.isText())
- EmitUniquedSection = TM.getFunctionSections();
- else
- EmitUniquedSection = TM.getDataSections();
- }
-
- if (EmitUniquedSection || GV->hasComdat()) {
- StringRef Prefix = getSectionPrefixForGlobal(Kind);
-
- SmallString<128> Name(Prefix);
- bool UniqueSectionNames = TM.getUniqueSectionNames();
- if (UniqueSectionNames) {
- Name.push_back('.');
- TM.getNameWithPrefix(Name, GV, Mang, true);
+static const MCSectionELF *
+selectELFSectionForGlobal(MCContext &Ctx, const GlobalValue *GV,
+ SectionKind Kind, Mangler &Mang,
+ const TargetMachine &TM, bool EmitUniqueSection,
+ unsigned Flags, unsigned *NextUniqueID) {
+ unsigned EntrySize = 0;
+ if (Kind.isMergeableCString()) {
+ if (Kind.isMergeable2ByteCString()) {
+ EntrySize = 2;
+ } else if (Kind.isMergeable4ByteCString()) {
+ EntrySize = 4;
+ } else {
+ EntrySize = 1;
+ assert(Kind.isMergeable1ByteCString() && "unknown string width");
}
- StringRef Group = "";
- if (const Comdat *C = getELFComdat(GV)) {
- Flags |= ELF::SHF_GROUP;
- Group = C->getName();
+ } else if (Kind.isMergeableConst()) {
+ if (Kind.isMergeableConst4()) {
+ EntrySize = 4;
+ } else if (Kind.isMergeableConst8()) {
+ EntrySize = 8;
+ } else {
+ assert(Kind.isMergeableConst16() && "unknown data width");
+ EntrySize = 16;
}
-
- return getContext().getELFSection(Name, getELFSectionType(Name, Kind),
- Flags, 0, Group, !UniqueSectionNames);
}
- if (Kind.isText()) return TextSection;
+ StringRef Group = "";
+ if (const Comdat *C = getELFComdat(GV)) {
+ Flags |= ELF::SHF_GROUP;
+ Group = C->getName();
+ }
+ bool UniqueSectionNames = TM.getUniqueSectionNames();
+ SmallString<128> Name;
if (Kind.isMergeableCString()) {
-
// We also need alignment here.
// FIXME: this is getting the alignment of the character, not the
// alignment of the global!
unsigned Align =
TM.getDataLayout()->getPreferredAlignment(cast<GlobalVariable>(GV));
- unsigned EntrySize = 1;
- if (Kind.isMergeable2ByteCString())
- EntrySize = 2;
- else if (Kind.isMergeable4ByteCString())
- EntrySize = 4;
- else
- assert(Kind.isMergeable1ByteCString() && "unknown string width");
-
std::string SizeSpec = ".rodata.str" + utostr(EntrySize) + ".";
- std::string Name = SizeSpec + utostr(Align);
- return getContext().getELFSection(
- Name, ELF::SHT_PROGBITS,
- ELF::SHF_ALLOC | ELF::SHF_MERGE | ELF::SHF_STRINGS, EntrySize, "");
+ Name = SizeSpec + utostr(Align);
+ } else if (Kind.isMergeableConst()) {
+ Name = ".rodata.cst";
+ Name += utostr(EntrySize);
+ } else {
+ Name = getSectionPrefixForGlobal(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 (EmitUniqueSection && UniqueSectionNames) {
+ Name.push_back('.');
+ TM.getNameWithPrefix(Name, GV, Mang, true);
}
+ unsigned UniqueID = ~0;
+ if (EmitUniqueSection && !UniqueSectionNames) {
+ UniqueID = *NextUniqueID;
+ (*NextUniqueID)++;
+ }
+ return Ctx.getELFSection(Name, getELFSectionType(Name, Kind), Flags,
+ EntrySize, Group, UniqueID);
+}
- 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;
+const MCSection *TargetLoweringObjectFileELF::SelectSectionForGlobal(
+ const GlobalValue *GV, SectionKind Kind, Mangler &Mang,
+ const TargetMachine &TM) const {
+ unsigned Flags = getELFSectionFlags(Kind);
- if (Kind.isDataNoRel()) return DataSection;
- if (Kind.isDataRelLocal()) return DataRelLocalSection;
- if (Kind.isDataRel()) return DataRelSection;
- if (Kind.isReadOnlyWithRelLocal()) return DataRelROLocalSection;
+ // If we have -ffunction-section or -fdata-section then we should emit the
+ // global value to a uniqued section specifically for it.
+ bool EmitUniqueSection = false;
+ if (!(Flags & ELF::SHF_MERGE) && !Kind.isCommon()) {
+ if (Kind.isText())
+ EmitUniqueSection = TM.getFunctionSections();
+ else
+ EmitUniqueSection = TM.getDataSections();
+ }
+ EmitUniqueSection |= GV->hasComdat();
- assert(Kind.isReadOnlyWithRel() && "Unknown section kind");
- return DataRelROSection;
+ return selectELFSectionForGlobal(getContext(), GV, Kind, Mang, TM,
+ EmitUniqueSection, Flags, &NextUniqueID);
}
const MCSection *TargetLoweringObjectFileELF::getSectionForJumpTable(
if (!EmitUniqueSection)
return ReadOnlySection;
- SmallString<128> Name(".rodata.");
- TM.getNameWithPrefix(Name, &F, Mang, true);
-
- unsigned Flags = ELF::SHF_ALLOC;
- StringRef Group = "";
- if (C) {
- Flags |= ELF::SHF_GROUP;
- Group = C->getName();
- }
+ return selectELFSectionForGlobal(getContext(), &F, SectionKind::getReadOnly(),
+ Mang, TM, EmitUniqueSection, ELF::SHF_ALLOC,
+ &NextUniqueID);
+}
- return getContext().getELFSection(Name, ELF::SHT_PROGBITS, Flags, 0, Group);
+bool TargetLoweringObjectFileELF::shouldPutJumpTableInFunctionSection(
+ bool UsesLabelDifference, const Function &F) const {
+ // We can always create relative relocations, so use another section
+ // that can be marked non-executable.
+ return false;
}
/// getSectionForConstant - Given a mergeable constant with the
// MachO
//===----------------------------------------------------------------------===//
+TargetLoweringObjectFileMachO::TargetLoweringObjectFileMachO()
+ : TargetLoweringObjectFile() {
+ SupportIndirectSymViaGOTPCRel = true;
+}
+
/// getDepLibFromLinkerOpt - Extract the dependent library name from a linker
/// option string. Returns StringRef() if the option does not specify a library.
StringRef TargetLoweringObjectFileMachO::
return SSym;
}
+const MCExpr *TargetLoweringObjectFileMachO::getIndirectSymViaGOTPCRel(
+ const MCSymbol *Sym, const MCValue &MV, int64_t Offset,
+ MachineModuleInfo *MMI, MCStreamer &Streamer) const {
+ // Although MachO 32-bit targets do not explictly have a GOTPCREL relocation
+ // as 64-bit do, we replace the GOT equivalent by accessing the final symbol
+ // through a non_lazy_ptr stub instead. One advantage is that it allows the
+ // computation of deltas to final external symbols. Example:
+ //
+ // _extgotequiv:
+ // .long _extfoo
+ //
+ // _delta:
+ // .long _extgotequiv-_delta
+ //
+ // is transformed to:
+ //
+ // _delta:
+ // .long L_extfoo$non_lazy_ptr-(_delta+0)
+ //
+ // .section __IMPORT,__pointers,non_lazy_symbol_pointers
+ // L_extfoo$non_lazy_ptr:
+ // .indirect_symbol _extfoo
+ // .long 0
+ //
+ MachineModuleInfoMachO &MachOMMI =
+ MMI->getObjFileInfo<MachineModuleInfoMachO>();
+ MCContext &Ctx = getContext();
+
+ // The offset must consider the original displacement from the base symbol
+ // since 32-bit targets don't have a GOTPCREL to fold the PC displacement.
+ Offset = -MV.getConstant();
+ const MCSymbol *BaseSym = &MV.getSymB()->getSymbol();
+
+ // Access the final symbol via sym$non_lazy_ptr and generate the appropriated
+ // non_lazy_ptr stubs.
+ SmallString<128> Name;
+ StringRef Suffix = "$non_lazy_ptr";
+ Name += DL->getPrivateGlobalPrefix();
+ Name += Sym->getName();
+ Name += Suffix;
+ MCSymbol *Stub = Ctx.GetOrCreateSymbol(Name);
+
+ MachineModuleInfoImpl::StubValueTy &StubSym = MachOMMI.getGVStubEntry(Stub);
+ if (!StubSym.getPointer())
+ StubSym = MachineModuleInfoImpl::
+ StubValueTy(const_cast<MCSymbol *>(Sym), true /* access indirectly */);
+
+ const MCExpr *BSymExpr =
+ MCSymbolRefExpr::Create(BaseSym, MCSymbolRefExpr::VK_None, Ctx);
+ const MCExpr *LHS =
+ MCSymbolRefExpr::Create(Stub, MCSymbolRefExpr::VK_None, Ctx);
+
+ if (!Offset)
+ return MCBinaryExpr::CreateSub(LHS, BSymExpr, Ctx);
+
+ const MCExpr *RHS =
+ MCBinaryExpr::CreateAdd(BSymExpr, MCConstantExpr::Create(Offset, Ctx), Ctx);
+ return MCBinaryExpr::CreateSub(LHS, RHS, Ctx);
+}
+
//===----------------------------------------------------------------------===//
// COFF
//===----------------------------------------------------------------------===//
StringRef COMDATSymName = Sym->getName();
return getContext().getCOFFSection(Name, Characteristics, Kind,
COMDATSymName, Selection);
+ } else {
+ SmallString<256> TmpData;
+ getNameWithPrefix(TmpData, GV, /*CannotUsePrivateLabel=*/true, Mang, TM);
+ return getContext().getCOFFSection(Name, Characteristics, Kind, TmpData,
+ Selection);
}
}
return DataSection;
}
+void TargetLoweringObjectFileCOFF::getNameWithPrefix(
+ SmallVectorImpl<char> &OutName, const GlobalValue *GV,
+ bool CannotUsePrivateLabel, Mangler &Mang, const TargetMachine &TM) const {
+ if (GV->hasPrivateLinkage() &&
+ ((isa<Function>(GV) && TM.getFunctionSections()) ||
+ (isa<GlobalVariable>(GV) && TM.getDataSections())))
+ CannotUsePrivateLabel = true;
+
+ Mang.getNameWithPrefix(OutName, GV, CannotUsePrivateLabel);
+}
+
+const MCSection *TargetLoweringObjectFileCOFF::getSectionForJumpTable(
+ const Function &F, Mangler &Mang, const TargetMachine &TM) const {
+ // If the function can be removed, produce a unique section so that
+ // the table doesn't prevent the removal.
+ const Comdat *C = F.getComdat();
+ bool EmitUniqueSection = TM.getFunctionSections() || C;
+ if (!EmitUniqueSection)
+ return ReadOnlySection;
+
+ // FIXME: we should produce a symbol for F instead.
+ if (F.hasPrivateLinkage())
+ return ReadOnlySection;
+
+ MCSymbol *Sym = TM.getSymbol(&F, Mang);
+ StringRef COMDATSymName = Sym->getName();
+
+ SectionKind Kind = SectionKind::getReadOnly();
+ const char *Name = getCOFFSectionNameForUniqueGlobal(Kind);
+ unsigned Characteristics = getCOFFSectionFlags(Kind);
+ Characteristics |= COFF::IMAGE_SCN_LNK_COMDAT;
+
+ return getContext().getCOFFSection(Name, Characteristics, Kind, COMDATSymName,
+ COFF::IMAGE_COMDAT_SELECT_ASSOCIATIVE);
+}
+
StringRef TargetLoweringObjectFileCOFF::
getDepLibFromLinkerOpt(StringRef LinkerOption) const {
const char *LibCmd = "/DEFAULTLIB:";
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