diff --git a/lib/MC/ELFObjectWriter.cpp b/lib/MC/ELFObjectWriter.cpp index ebbba1327dd..f3a09c8df23 100644 --- a/lib/MC/ELFObjectWriter.cpp +++ b/lib/MC/ELFObjectWriter.cpp @@ -386,6 +386,8 @@ void ELFObjectWriterImpl::WriteSymbol(MCDataFragment *F, ELFSymbolData &MSD, if (Data.isCommon() && Data.isExternal()) Value = Data.getCommonAlignment(); + assert(!(Data.isCommon() && !Data.isExternal())); + if (!Data.isCommon() && !(Data.getFlags() & ELF_STB_Weak)) if (MCFragment *FF = Data.getFragment()) Value = Layout.getSymbolAddress(&Data) - @@ -502,7 +504,10 @@ void ELFObjectWriterImpl::RecordRelocation(const MCAssembler &Asm, if (Base) { if (F && (!Symbol->isInSection() || SD.isCommon()) && !SD.isExternal()) { Index = F->getParent()->getOrdinal() + LocalSymbolData.size() + 1; - Value += Layout.getSymbolAddress(&SD); + + MCSectionData *FSD = F->getParent(); + // Offset of the symbol in the section + Value += Layout.getSymbolAddress(&SD) - Layout.getSectionAddress(FSD); } else Index = getSymbolIndexInSymbolTable(Asm, Symbol); if (Base != &SD) @@ -672,7 +677,10 @@ void ELFObjectWriterImpl::ComputeSymbolTable(MCAssembler &Asm) { MSD.SymbolData = it; MSD.StringIndex = Entry; - if (Symbol.isUndefined()) { + if (it->isCommon()) { + MSD.SectionIndex = ELF::SHN_COMMON; + ExternalSymbolData.push_back(MSD); + } else if (Symbol.isUndefined()) { MSD.SectionIndex = ELF::SHN_UNDEF; // XXX: for some reason we dont Emit* this it->setFlags(it->getFlags() | ELF_STB_Global); @@ -680,9 +688,6 @@ void ELFObjectWriterImpl::ComputeSymbolTable(MCAssembler &Asm) { } else if (Symbol.isAbsolute()) { MSD.SectionIndex = ELF::SHN_ABS; ExternalSymbolData.push_back(MSD); - } else if (it->isCommon()) { - MSD.SectionIndex = ELF::SHN_COMMON; - ExternalSymbolData.push_back(MSD); } else { MSD.SectionIndex = SectionIndexMap.lookup(&Symbol.getSection()); assert(MSD.SectionIndex && "Invalid section index!"); diff --git a/lib/MC/MCELFStreamer.cpp b/lib/MC/MCELFStreamer.cpp index deb1a0de208..fd015946137 100644 --- a/lib/MC/MCELFStreamer.cpp +++ b/lib/MC/MCELFStreamer.cpp @@ -13,6 +13,7 @@ #include "llvm/MC/MCStreamer.h" +#include "llvm/ADT/SmallPtrSet.h" #include "llvm/MC/MCAssembler.h" #include "llvm/MC/MCContext.h" #include "llvm/MC/MCCodeEmitter.h" @@ -109,6 +110,8 @@ public: virtual void EmitInstruction(const MCInst &Inst); virtual void Finish(); +private: + SmallPtrSet BindingExplicitlySet; /// @} void SetSection(StringRef Section, unsigned Type, unsigned Flags, SectionKind Kind) { @@ -187,6 +190,13 @@ static void SetBinding(MCSymbolData &SD, unsigned Binding) { SD.setFlags(OtherFlags | (Binding << ELF_STB_Shift)); } +static unsigned GetBinding(const MCSymbolData &SD) { + uint32_t Binding = (SD.getFlags() & (0xf << ELF_STB_Shift)) >> ELF_STB_Shift; + assert(Binding == ELF::STB_LOCAL || Binding == ELF::STB_GLOBAL || + Binding == ELF::STB_WEAK); + return Binding; +} + static void SetType(MCSymbolData &SD, unsigned Type) { assert(Type == ELF::STT_NOTYPE || Type == ELF::STT_OBJECT || Type == ELF::STT_FUNC || Type == ELF::STT_SECTION || @@ -246,15 +256,19 @@ void MCELFStreamer::EmitSymbolAttribute(MCSymbol *Symbol, case MCSA_Global: SetBinding(SD, ELF::STB_GLOBAL); SD.setExternal(true); + BindingExplicitlySet.insert(Symbol); break; case MCSA_WeakReference: case MCSA_Weak: SetBinding(SD, ELF::STB_WEAK); + BindingExplicitlySet.insert(Symbol); break; case MCSA_Local: SetBinding(SD, ELF::STB_LOCAL); + SD.setExternal(false); + BindingExplicitlySet.insert(Symbol); break; case MCSA_ELF_TypeFunction: @@ -295,7 +309,12 @@ void MCELFStreamer::EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size, unsigned ByteAlignment) { MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol); - if ((SD.getFlags() & (0xf << ELF_STB_Shift)) == ELF_STB_Local) { + if (!BindingExplicitlySet.count(Symbol)) { + SetBinding(SD, ELF::STB_GLOBAL); + SD.setExternal(true); + } + + if (GetBinding(SD) == ELF_STB_Local) { const MCSection *Section = getAssembler().getContext().getELFSection(".bss", MCSectionELF::SHT_NOBITS, MCSectionELF::SHF_WRITE | @@ -306,13 +325,11 @@ void MCELFStreamer::EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size, MCFragment *F = new MCFillFragment(0, 0, Size, &SectData); SD.setFragment(F); Symbol->setSection(*Section); - SD.setSize(MCConstantExpr::Create(Size, getContext())); + } else { + SD.setCommon(Size, ByteAlignment); } - SetBinding(SD, ELF::STB_GLOBAL); - SD.setExternal(true); - - SD.setCommon(Size, ByteAlignment); + SD.setSize(MCConstantExpr::Create(Size, getContext())); } void MCELFStreamer::EmitBytes(StringRef Data, unsigned AddrSpace) { diff --git a/lib/MC/MCParser/AsmParser.cpp b/lib/MC/MCParser/AsmParser.cpp index c5d2aa078aa..84606bc3104 100644 --- a/lib/MC/MCParser/AsmParser.cpp +++ b/lib/MC/MCParser/AsmParser.cpp @@ -961,6 +961,9 @@ bool AsmParser::ParseStatement() { if (IDVal == ".globl" || IDVal == ".global") return ParseDirectiveSymbolAttribute(MCSA_Global); + // ELF only? Should it be here? + if (IDVal == ".local") + return ParseDirectiveSymbolAttribute(MCSA_Local); if (IDVal == ".hidden") return ParseDirectiveSymbolAttribute(MCSA_Hidden); if (IDVal == ".indirect_symbol") diff --git a/test/MC/ELF/common.s b/test/MC/ELF/common.s new file mode 100644 index 00000000000..18b3af5afa6 --- /dev/null +++ b/test/MC/ELF/common.s @@ -0,0 +1,63 @@ +// RUN: llvm-mc -filetype=obj -triple x86_64-pc-linux-gnu %s -o - | elf-dump --dump-section-data | FileCheck %s + + + .text + +// Test that this produces a regular local symbol. + .type common1,@object + .local common1 + .comm common1,1,1 + +// CHECK: ('st_name', 1) # 'common1' +// CHECK-NEXT: ('st_bind', 0) +// CHECK-NEXT: ('st_type', 1) +// CHECK-NEXT: ('st_other', 0) +// CHECK-NEXT: ('st_shndx', +// CHECK-NEXT: ('st_value', 0) +// CHECK-NEXT: ('st_size', 1) + + +// Same as common1, but with directives in a different order. + .local common2 + .type common2,@object + .comm common2,1,1 + +// CHECK: ('st_name', 9) # 'common2' +// CHECK-NEXT: ('st_bind', 0) +// CHECK-NEXT: ('st_type', 1) +// CHECK-NEXT: ('st_other', 0) +// CHECK-NEXT: ('st_shndx', +// CHECK-NEXT: ('st_value', 1) +// CHECK-NEXT: ('st_size', 1) + +// Test that without an explicit .local we produce a global. + .type common3,@object + .comm common3,4,4 + +// CHECK: ('st_name', 17) # 'common3' +// CHECK-NEXT: ('st_bind', 1) +// CHECK-NEXT: ('st_type', 1) +// CHECK-NEXT: ('st_other', 0) +// CHECK-NEXT: ('st_shndx', 65522) +// CHECK-NEXT: ('st_value', 4) +// CHECK-NEXT: ('st_size', 4) + + +// Test that without an explicit .local we produce a global, even if the first +// occurrence is not in a directive. + .globl foo + .type foo,@function +foo: + movsbl common4+3(%rip), %eax + + + .type common4,@object + .comm common4,40,16 + +// CHECK: ('st_name', 29) # 'common4' +// CHECK-NEXT: ('st_bind', 1) +// CHECK-NEXT: ('st_type', 1) +// CHECK-NEXT: ('st_other', 0) +// CHECK-NEXT: ('st_shndx', 65522) +// CHECK-NEXT: ('st_value', 16) +// CHECK-NEXT: ('st_size', 40)