X-Git-Url: http://plrg.eecs.uci.edu/git/?a=blobdiff_plain;ds=sidebyside;f=lib%2FMC%2FELFObjectWriter.cpp;h=edece8b63d4c1f1709524a0bd456becada6a74b3;hb=f4ccd110750a3f3fe6a107d5c74c649c2a0dc407;hp=4f66156f6de22bb20da280f336564ba3f32c0ba3;hpb=db3cc56e7018f6a553ba6bea8aeb6ee32aa121d8;p=oota-llvm.git diff --git a/lib/MC/ELFObjectWriter.cpp b/lib/MC/ELFObjectWriter.cpp index 4f66156f6de..edece8b63d4 100644 --- a/lib/MC/ELFObjectWriter.cpp +++ b/lib/MC/ELFObjectWriter.cpp @@ -12,7 +12,6 @@ //===----------------------------------------------------------------------===// #include "llvm/MC/MCELFObjectWriter.h" -#include "llvm/ADT/OwningPtr.h" #include "llvm/ADT/STLExtras.h" #include "llvm/ADT/SmallPtrSet.h" #include "llvm/ADT/SmallString.h" @@ -73,17 +72,13 @@ class ELFObjectWriter : public MCObjectWriter { // Support lexicographic sorting. bool operator<(const ELFSymbolData &RHS) const { - if (MCELF::GetType(*SymbolData) == ELF::STT_FILE) - return true; - if (MCELF::GetType(*RHS.SymbolData) == ELF::STT_FILE) - return false; return SymbolData->getSymbol().getName() < RHS.SymbolData->getSymbol().getName(); } }; /// The target specific ELF writer instance. - llvm::OwningPtr TargetObjectWriter; + std::unique_ptr TargetObjectWriter; SmallPtrSet UsedInReloc; SmallPtrSet WeakrefUsedInReloc; @@ -98,6 +93,7 @@ class ELFObjectWriter : public MCObjectWriter { /// @{ SmallString<256> StringTable; + std::vector FileSymbolData; std::vector LocalSymbolData; std::vector ExternalSymbolData; std::vector UndefinedSymbolData; @@ -535,6 +531,41 @@ void ELFObjectWriter::ExecutePostLayoutBinding(MCAssembler &Asm, } } +static uint8_t mergeTypeForSet(uint8_t origType, uint8_t newType) { + uint8_t Type = newType; + + // Propagation rules: + // IFUNC > FUNC > OBJECT > NOTYPE + // TLS_OBJECT > OBJECT > NOTYPE + // + // dont let the new type degrade the old type + switch (origType) { + default: + break; + case ELF::STT_GNU_IFUNC: + if (Type == ELF::STT_FUNC || Type == ELF::STT_OBJECT || + Type == ELF::STT_NOTYPE || Type == ELF::STT_TLS) + Type = ELF::STT_GNU_IFUNC; + break; + case ELF::STT_FUNC: + if (Type == ELF::STT_OBJECT || Type == ELF::STT_NOTYPE || + Type == ELF::STT_TLS) + Type = ELF::STT_FUNC; + break; + case ELF::STT_OBJECT: + if (Type == ELF::STT_NOTYPE) + Type = ELF::STT_OBJECT; + break; + case ELF::STT_TLS: + if (Type == ELF::STT_OBJECT || Type == ELF::STT_NOTYPE || + Type == ELF::STT_GNU_IFUNC || Type == ELF::STT_FUNC) + Type = ELF::STT_TLS; + break; + } + + return Type; +} + void ELFObjectWriter::WriteSymbol(MCDataFragment *SymtabF, MCDataFragment *ShndxF, ELFSymbolData &MSD, @@ -548,14 +579,13 @@ void ELFObjectWriter::WriteSymbol(MCDataFragment *SymtabF, // Binding and Type share the same byte as upper and lower nibbles uint8_t Binding = MCELF::GetBinding(OrigData); - uint8_t Type = MCELF::GetType(Data); + uint8_t Type = mergeTypeForSet(MCELF::GetType(OrigData), MCELF::GetType(Data)); uint8_t Info = (Binding << ELF_STB_Shift) | (Type << ELF_STT_Shift); - // Other and Visibility share the same byte with Visability using the lower + // Other and Visibility share the same byte with Visibility using the lower // 2 bits uint8_t Visibility = MCELF::GetVisibility(OrigData); - uint8_t Other = MCELF::getOther(OrigData) << - (ELF_Other_Shift - ELF_STV_Shift); + uint8_t Other = MCELF::getOther(OrigData) << (ELF_STO_Shift - ELF_STV_Shift); Other |= Visibility; uint64_t Value = SymbolValue(Data, Layout); @@ -590,8 +620,15 @@ void ELFObjectWriter::WriteSymbolTable(MCDataFragment *SymtabF, // The first entry is the undefined symbol entry. WriteSymbolEntry(SymtabF, ShndxF, 0, 0, 0, 0, 0, 0, false); + for (unsigned i = 0, e = FileSymbolData.size(); i != e; ++i) { + WriteSymbolEntry(SymtabF, ShndxF, FileSymbolData[i], + ELF::STT_FILE | ELF::STB_LOCAL, 0, 0, + ELF::STV_DEFAULT, ELF::SHN_ABS, true); + } + // Write the symbol table entries. - LastLocalSymbolIndex = LocalSymbolData.size() + 1; + LastLocalSymbolIndex = FileSymbolData.size() + LocalSymbolData.size() + 1; + for (unsigned i = 0, e = LocalSymbolData.size(); i != e; ++i) { ELFSymbolData &MSD = LocalSymbolData[i]; WriteSymbol(SymtabF, ShndxF, MSD, Layout); @@ -717,6 +754,12 @@ void ELFObjectWriter::RecordRelocation(const MCAssembler &Asm, MCSymbolData &SDB = Asm.getSymbolData(SymbolB); IsPCRel = true; + if (!SDB.getFragment()) + Asm.getContext().FatalError( + Fixup.getLoc(), + Twine("symbol '") + SymbolB.getName() + + "' can not be undefined in a subtraction expression"); + // Offset of the symbol in the section int64_t a = Layout.getSymbolOffset(&SDB); @@ -804,9 +847,6 @@ bool ELFObjectWriter::isInSymtab(const MCAssembler &Asm, if (!Symbol.isVariable() && Symbol.isUndefined() && !IsGlobal) return false; - if (!Asm.isSymbolLinkerVisible(Symbol) && !Symbol.isUndefined()) - return false; - if (Symbol.isTemporary()) return false; @@ -880,6 +920,20 @@ void ELFObjectWriter::ComputeSymbolTable(MCAssembler &Asm, // FIXME: We could optimize suffixes in strtab in the same way we // optimize them in shstrtab. + for (MCAssembler::const_file_name_iterator it = Asm.file_names_begin(), + ie = Asm.file_names_end(); + it != ie; + ++it) { + StringRef Name = *it; + uint64_t &Entry = StringIndexMap[Name]; + if (!Entry) { + Entry = StringTable.size(); + StringTable += Name; + StringTable += '\x00'; + } + FileSymbolData.push_back(Entry); + } + // Add the data for the symbols. for (MCAssembler::symbol_iterator it = Asm.symbol_begin(), ie = Asm.symbol_end(); it != ie; ++it) { @@ -964,7 +1018,7 @@ void ELFObjectWriter::ComputeSymbolTable(MCAssembler &Asm, // Set the symbol indices. Local symbols must come before all other // symbols with non-local bindings. - unsigned Index = 1; + unsigned Index = FileSymbolData.size() + 1; for (unsigned i = 0, e = LocalSymbolData.size(); i != e; ++i) LocalSymbolData[i].SymbolData->setIndex(Index++); @@ -1002,11 +1056,18 @@ void ELFObjectWriter::CreateRelocationSections(MCAssembler &Asm, else EntrySize = is64Bit() ? sizeof(ELF::Elf64_Rel) : sizeof(ELF::Elf32_Rel); + unsigned Flags = 0; + StringRef Group = ""; + if (Section.getFlags() & ELF::SHF_GROUP) { + Flags = ELF::SHF_GROUP; + Group = Section.getGroup()->getName(); + } + const MCSectionELF *RelaSection = Ctx.getELFSection(RelaSectionName, hasRelocationAddend() ? - ELF::SHT_RELA : ELF::SHT_REL, 0, + ELF::SHT_RELA : ELF::SHT_REL, Flags, SectionKind::getReadOnly(), - EntrySize, ""); + EntrySize, Group); RelMap[&Section] = RelaSection; Asm.getOrCreateSectionData(*RelaSection); } @@ -1066,7 +1127,7 @@ void ELFObjectWriter::WriteRelocationsFragment(const MCAssembler &Asm, else if (entry.Index < 0) entry.Index = getSymbolIndexInSymbolTable(Asm, entry.Symbol); else - entry.Index += LocalSymbolData.size(); + entry.Index += FileSymbolData.size() + LocalSymbolData.size(); if (is64Bit()) { String64(*F, entry.r_offset); if (TargetObjectWriter->isN64()) { @@ -1097,11 +1158,10 @@ void ELFObjectWriter::WriteRelocationsFragment(const MCAssembler &Asm, } } -static int compareBySuffix(const void *a, const void *b) { - const MCSectionELF *secA = *static_cast(a); - const MCSectionELF *secB = *static_cast(b); - const StringRef &NameA = secA->getSectionName(); - const StringRef &NameB = secB->getSectionName(); +static int compareBySuffix(const MCSectionELF *const *a, + const MCSectionELF *const *b) { + const StringRef &NameA = (*a)->getSectionName(); + const StringRef &NameB = (*b)->getSectionName(); const unsigned sizeA = NameA.size(); const unsigned sizeB = NameB.size(); const unsigned len = std::min(sizeA, sizeB); @@ -1292,10 +1352,12 @@ void ELFObjectWriter::WriteSection(MCAssembler &Asm, // Remove ".rel" and ".rela" prefixes. unsigned SecNameLen = (Section.getType() == ELF::SHT_REL) ? 4 : 5; StringRef SectionName = Section.getSectionName().substr(SecNameLen); + StringRef GroupName = + Section.getGroup() ? Section.getGroup()->getName() : ""; - InfoSection = Asm.getContext().getELFSection(SectionName, - ELF::SHT_PROGBITS, 0, - SectionKind::getReadOnly()); + InfoSection = Asm.getContext().getELFSection(SectionName, ELF::SHT_PROGBITS, + 0, SectionKind::getReadOnly(), + 0, GroupName); sh_info = SectionIndexMap.lookup(InfoSection); break; } @@ -1345,11 +1407,12 @@ void ELFObjectWriter::WriteSection(MCAssembler &Asm, ELF::SHF_EXECINSTR | ELF::SHF_ALLOC, SectionKind::getText())); } else if (SecName.startswith(".ARM.exidx")) { - sh_link = SectionIndexMap.lookup( - Asm.getContext().getELFSection(SecName.substr(sizeof(".ARM.exidx") - 1), - ELF::SHT_PROGBITS, - ELF::SHF_EXECINSTR | ELF::SHF_ALLOC, - SectionKind::getText())); + StringRef GroupName = + Section.getGroup() ? Section.getGroup()->getName() : ""; + sh_link = SectionIndexMap.lookup(Asm.getContext().getELFSection( + SecName.substr(sizeof(".ARM.exidx") - 1), ELF::SHT_PROGBITS, + ELF::SHF_EXECINSTR | ELF::SHF_ALLOC, SectionKind::getText(), 0, + GroupName)); } } @@ -1578,7 +1641,7 @@ ELFObjectWriter::IsSymbolRefDifferenceFullyResolvedImpl(const MCAssembler &Asm, const MCFragment &FB, bool InSet, bool IsPCRel) const { - if (DataA.getFlags() & ELF_STB_Weak) + if (DataA.getFlags() & ELF_STB_Weak || MCELF::GetType(DataA) == ELF::STT_GNU_IFUNC) return false; return MCObjectWriter::IsSymbolRefDifferenceFullyResolvedImpl( Asm, DataA, FB,InSet, IsPCRel);