diff options
Diffstat (limited to 'contrib/llvm/tools/lld/ELF/InputSection.cpp')
| -rw-r--r-- | contrib/llvm/tools/lld/ELF/InputSection.cpp | 641 |
1 files changed, 376 insertions, 265 deletions
diff --git a/contrib/llvm/tools/lld/ELF/InputSection.cpp b/contrib/llvm/tools/lld/ELF/InputSection.cpp index 6564e79..6b1e928 100644 --- a/contrib/llvm/tools/lld/ELF/InputSection.cpp +++ b/contrib/llvm/tools/lld/ELF/InputSection.cpp @@ -13,103 +13,138 @@ #include "Error.h" #include "InputFiles.h" #include "LinkerScript.h" +#include "Memory.h" #include "OutputSections.h" +#include "Relocations.h" +#include "SyntheticSections.h" #include "Target.h" #include "Thunks.h" - +#include "llvm/Object/Decompressor.h" #include "llvm/Support/Compression.h" #include "llvm/Support/Endian.h" +#include <mutex> using namespace llvm; using namespace llvm::ELF; using namespace llvm::object; +using namespace llvm::support; using namespace llvm::support::endian; using namespace lld; using namespace lld::elf; -template <class ELFT> bool elf::isDiscarded(InputSectionBase<ELFT> *S) { - return !S || S == &InputSection<ELFT>::Discarded || !S->Live || - Script<ELFT>::X->isDiscarded(S); +// Returns a string to construct an error message. +template <class ELFT> +std::string lld::toString(const InputSectionBase<ELFT> *Sec) { + // File can be absent if section is synthetic. + std::string FileName = + Sec->getFile() ? Sec->getFile()->getName() : "<internal>"; + return (FileName + ":(" + Sec->Name + ")").str(); +} + +template <class ELFT> +static ArrayRef<uint8_t> getSectionContents(elf::ObjectFile<ELFT> *File, + const typename ELFT::Shdr *Hdr) { + if (!File || Hdr->sh_type == SHT_NOBITS) + return makeArrayRef<uint8_t>(nullptr, Hdr->sh_size); + return check(File->getObj().getSectionContents(Hdr)); } template <class ELFT> InputSectionBase<ELFT>::InputSectionBase(elf::ObjectFile<ELFT> *File, - const Elf_Shdr *Header, + uintX_t Flags, uint32_t Type, + uintX_t Entsize, uint32_t Link, + uint32_t Info, uintX_t Addralign, + ArrayRef<uint8_t> Data, StringRef Name, Kind SectionKind) - : Header(Header), File(File), SectionKind(SectionKind), Repl(this), - Compressed(Header->sh_flags & SHF_COMPRESSED) { - // The garbage collector sets sections' Live bits. - // If GC is disabled, all sections are considered live by default. - Live = !Config->GcSections; + : InputSectionData(SectionKind, Name, Data, + !Config->GcSections || !(Flags & SHF_ALLOC)), + File(File), Flags(Flags), Entsize(Entsize), Type(Type), Link(Link), + Info(Info), Repl(this) { + NumRelocations = 0; + AreRelocsRela = false; // The ELF spec states that a value of 0 means the section has // no alignment constraits. - Alignment = std::max<uintX_t>(Header->sh_addralign, 1); + uint64_t V = std::max<uint64_t>(Addralign, 1); + if (!isPowerOf2_64(V)) + fatal(toString(File) + ": section sh_addralign is not a power of 2"); + + // We reject object files having insanely large alignments even though + // they are allowed by the spec. I think 4GB is a reasonable limitation. + // We might want to relax this in the future. + if (V > UINT32_MAX) + fatal(toString(File) + ": section sh_addralign is too large"); + Alignment = V; + + // If it is not a mergeable section, overwrite the flag so that the flag + // is consistent with the class. This inconsistency could occur when + // string merging is disabled using -O0 flag. + if (!Config->Relocatable && !isa<MergeInputSection<ELFT>>(this)) + this->Flags &= ~(SHF_MERGE | SHF_STRINGS); +} + +template <class ELFT> +InputSectionBase<ELFT>::InputSectionBase(elf::ObjectFile<ELFT> *File, + const Elf_Shdr *Hdr, StringRef Name, + Kind SectionKind) + : InputSectionBase(File, Hdr->sh_flags & ~SHF_INFO_LINK, Hdr->sh_type, + Hdr->sh_entsize, Hdr->sh_link, Hdr->sh_info, + Hdr->sh_addralign, getSectionContents(File, Hdr), Name, + SectionKind) { + this->Offset = Hdr->sh_offset; } template <class ELFT> size_t InputSectionBase<ELFT>::getSize() const { + if (auto *S = dyn_cast<SyntheticSection<ELFT>>(this)) + return S->getSize(); + if (auto *D = dyn_cast<InputSection<ELFT>>(this)) if (D->getThunksSize() > 0) return D->getThunkOff() + D->getThunksSize(); - return Header->sh_size; -} - -template <class ELFT> StringRef InputSectionBase<ELFT>::getSectionName() const { - return check(File->getObj().getSectionName(this->Header)); -} -template <class ELFT> -ArrayRef<uint8_t> InputSectionBase<ELFT>::getSectionData() const { - if (Compressed) - return ArrayRef<uint8_t>((const uint8_t *)Uncompressed.data(), - Uncompressed.size()); - return check(this->File->getObj().getSectionContents(this->Header)); + return Data.size(); } template <class ELFT> typename ELFT::uint InputSectionBase<ELFT>::getOffset(uintX_t Offset) const { - switch (SectionKind) { + switch (kind()) { case Regular: return cast<InputSection<ELFT>>(this)->OutSecOff + Offset; + case Synthetic: + // For synthetic sections we treat offset -1 as the end of the section. + // The same approach is used for synthetic symbols (DefinedSynthetic). + return cast<InputSection<ELFT>>(this)->OutSecOff + + (Offset == uintX_t(-1) ? getSize() : Offset); case EHFrame: - return cast<EhInputSection<ELFT>>(this)->getOffset(Offset); + // The file crtbeginT.o has relocations pointing to the start of an empty + // .eh_frame that is known to be the first in the link. It does that to + // identify the start of the output .eh_frame. + return Offset; case Merge: return cast<MergeInputSection<ELFT>>(this)->getOffset(Offset); - case MipsReginfo: - case MipsOptions: - // MIPS .reginfo and .MIPS.options sections are consumed by the linker, - // and the linker produces a single output section. It is possible that - // input files contain section symbol points to the corresponding input - // section. Redirect it to the produced output section. - if (Offset != 0) - fatal("Unsupported reference to the middle of '" + getSectionName() + - "' section"); - return this->OutSec->getVA(); } llvm_unreachable("invalid section kind"); } +// Uncompress section contents. Note that this function is called +// from parallel_for_each, so it must be thread-safe. template <class ELFT> void InputSectionBase<ELFT>::uncompress() { - if (!zlib::isAvailable()) - fatal("build lld with zlib to enable compressed sections support"); - - // A compressed section consists of a header of Elf_Chdr type - // followed by compressed data. - ArrayRef<uint8_t> Data = - check(this->File->getObj().getSectionContents(this->Header)); - if (Data.size() < sizeof(Elf_Chdr)) - fatal("corrupt compressed section"); - - auto *Hdr = reinterpret_cast<const Elf_Chdr *>(Data.data()); - Data = Data.slice(sizeof(Elf_Chdr)); - - if (Hdr->ch_type != ELFCOMPRESS_ZLIB) - fatal("unsupported compression type"); + Decompressor Decompressor = check(Decompressor::create( + Name, toStringRef(Data), ELFT::TargetEndianness == llvm::support::little, + ELFT::Is64Bits)); + + size_t Size = Decompressor.getDecompressedSize(); + char *OutputBuf; + { + static std::mutex Mu; + std::lock_guard<std::mutex> Lock(Mu); + OutputBuf = BAlloc.Allocate<char>(Size); + } - StringRef Buf((const char *)Data.data(), Data.size()); - if (zlib::uncompress(Buf, Uncompressed, Hdr->ch_size) != zlib::StatusOK) - fatal("error uncompressing section"); + if (Error E = Decompressor.decompress({OutputBuf, Size})) + fatal(E, toString(this)); + Data = ArrayRef<uint8_t>((uint8_t *)OutputBuf, Size); } template <class ELFT> @@ -119,29 +154,71 @@ InputSectionBase<ELFT>::getOffset(const DefinedRegular<ELFT> &Sym) const { } template <class ELFT> +InputSectionBase<ELFT> *InputSectionBase<ELFT>::getLinkOrderDep() const { + if ((Flags & SHF_LINK_ORDER) && Link != 0) + return getFile()->getSections()[Link]; + return nullptr; +} + +// Returns a source location string. Used to construct an error message. +template <class ELFT> +std::string InputSectionBase<ELFT>::getLocation(typename ELFT::uint Offset) { + // First check if we can get desired values from debugging information. + std::string LineInfo = File->getLineInfo(this, Offset); + if (!LineInfo.empty()) + return LineInfo; + + // File->SourceFile contains STT_FILE symbol that contains a + // source file name. If it's missing, we use an object file name. + std::string SrcFile = File->SourceFile; + if (SrcFile.empty()) + SrcFile = toString(File); + + // Find a function symbol that encloses a given location. + for (SymbolBody *B : File->getSymbols()) + if (auto *D = dyn_cast<DefinedRegular<ELFT>>(B)) + if (D->Section == this && D->Type == STT_FUNC) + if (D->Value <= Offset && Offset < D->Value + D->Size) + return SrcFile + ":(function " + toString(*D) + ")"; + + // If there's no symbol, print out the offset in the section. + return (SrcFile + ":(" + Name + "+0x" + utohexstr(Offset) + ")").str(); +} + +template <class ELFT> +InputSection<ELFT>::InputSection() : InputSectionBase<ELFT>() {} + +template <class ELFT> +InputSection<ELFT>::InputSection(uintX_t Flags, uint32_t Type, + uintX_t Addralign, ArrayRef<uint8_t> Data, + StringRef Name, Kind K) + : InputSectionBase<ELFT>(nullptr, Flags, Type, + /*Entsize*/ 0, /*Link*/ 0, /*Info*/ 0, Addralign, + Data, Name, K) {} + +template <class ELFT> InputSection<ELFT>::InputSection(elf::ObjectFile<ELFT> *F, - const Elf_Shdr *Header) - : InputSectionBase<ELFT>(F, Header, Base::Regular) {} + const Elf_Shdr *Header, StringRef Name) + : InputSectionBase<ELFT>(F, Header, Name, Base::Regular) {} template <class ELFT> -bool InputSection<ELFT>::classof(const InputSectionBase<ELFT> *S) { - return S->SectionKind == Base::Regular; +bool InputSection<ELFT>::classof(const InputSectionData *S) { + return S->kind() == Base::Regular || S->kind() == Base::Synthetic; } template <class ELFT> InputSectionBase<ELFT> *InputSection<ELFT>::getRelocatedSection() { - assert(this->Header->sh_type == SHT_RELA || this->Header->sh_type == SHT_REL); + assert(this->Type == SHT_RELA || this->Type == SHT_REL); ArrayRef<InputSectionBase<ELFT> *> Sections = this->File->getSections(); - return Sections[this->Header->sh_info]; + return Sections[this->Info]; } -template <class ELFT> -void InputSection<ELFT>::addThunk(const Thunk<ELFT> *T) { +template <class ELFT> void InputSection<ELFT>::addThunk(const Thunk<ELFT> *T) { Thunks.push_back(T); } template <class ELFT> uint64_t InputSection<ELFT>::getThunkOff() const { - return this->Header->sh_size; + return this->Data.size(); } template <class ELFT> uint64_t InputSection<ELFT>::getThunksSize() const { @@ -163,35 +240,63 @@ void InputSection<ELFT>::copyRelocations(uint8_t *Buf, ArrayRef<RelTy> Rels) { uint32_t Type = Rel.getType(Config->Mips64EL); SymbolBody &Body = this->File->getRelocTargetSym(Rel); - RelTy *P = reinterpret_cast<RelTy *>(Buf); + Elf_Rela *P = reinterpret_cast<Elf_Rela *>(Buf); Buf += sizeof(RelTy); + if (Config->Rela) + P->r_addend = getAddend<ELFT>(Rel); P->r_offset = RelocatedSection->getOffset(Rel.r_offset); - P->setSymbolAndType(Body.DynsymIndex, Type, Config->Mips64EL); + P->setSymbolAndType(In<ELFT>::SymTab->getSymbolIndex(&Body), Type, + Config->Mips64EL); } } -// Page(Expr) is the page address of the expression Expr, defined -// as (Expr & ~0xFFF). (This applies even if the machine page size -// supported by the platform has a different value.) -static uint64_t getAArch64Page(uint64_t Expr) { - return Expr & (~static_cast<uint64_t>(0xFFF)); +static uint32_t getARMUndefinedRelativeWeakVA(uint32_t Type, uint32_t A, + uint32_t P) { + switch (Type) { + case R_ARM_THM_JUMP11: + return P + 2; + case R_ARM_CALL: + case R_ARM_JUMP24: + case R_ARM_PC24: + case R_ARM_PLT32: + case R_ARM_PREL31: + case R_ARM_THM_JUMP19: + case R_ARM_THM_JUMP24: + return P + 4; + case R_ARM_THM_CALL: + // We don't want an interworking BLX to ARM + return P + 5; + default: + return A; + } } -template <class ELFT> -static typename ELFT::uint getSymVA(uint32_t Type, typename ELFT::uint A, - typename ELFT::uint P, - const SymbolBody &Body, RelExpr Expr) { - typedef typename ELFT::uint uintX_t; +static uint64_t getAArch64UndefinedRelativeWeakVA(uint64_t Type, uint64_t A, + uint64_t P) { + switch (Type) { + case R_AARCH64_CALL26: + case R_AARCH64_CONDBR19: + case R_AARCH64_JUMP26: + case R_AARCH64_TSTBR14: + return P + 4; + default: + return A; + } +} +template <class ELFT> +static typename ELFT::uint +getRelocTargetVA(uint32_t Type, typename ELFT::uint A, typename ELFT::uint P, + const SymbolBody &Body, RelExpr Expr) { switch (Expr) { case R_HINT: + case R_TLSDESC_CALL: llvm_unreachable("cannot relocate hint relocs"); case R_TLSLD: - return Out<ELFT>::Got->getTlsIndexOff() + A - - Out<ELFT>::Got->getNumEntries() * sizeof(uintX_t); + return In<ELFT>::Got->getTlsIndexOff() + A - In<ELFT>::Got->getSize(); case R_TLSLD_PC: - return Out<ELFT>::Got->getTlsIndexVA() + A - P; + return In<ELFT>::Got->getTlsIndexVA() + A - P; case R_THUNK_ABS: return Body.getThunkVA<ELFT>() + A; case R_THUNK_PC: @@ -200,14 +305,14 @@ static typename ELFT::uint getSymVA(uint32_t Type, typename ELFT::uint A, case R_PPC_TOC: return getPPC64TocBase() + A; case R_TLSGD: - return Out<ELFT>::Got->getGlobalDynOffset(Body) + A - - Out<ELFT>::Got->getNumEntries() * sizeof(uintX_t); + return In<ELFT>::Got->getGlobalDynOffset(Body) + A - + In<ELFT>::Got->getSize(); case R_TLSGD_PC: - return Out<ELFT>::Got->getGlobalDynAddr(Body) + A - P; + return In<ELFT>::Got->getGlobalDynAddr(Body) + A - P; case R_TLSDESC: - return Out<ELFT>::Got->getGlobalDynAddr(Body) + A; + return In<ELFT>::Got->getGlobalDynAddr(Body) + A; case R_TLSDESC_PAGE: - return getAArch64Page(Out<ELFT>::Got->getGlobalDynAddr(Body) + A) - + return getAArch64Page(In<ELFT>::Got->getGlobalDynAddr(Body) + A) - getAArch64Page(P); case R_PLT: return Body.getPltVA<ELFT>() + A; @@ -217,11 +322,13 @@ static typename ELFT::uint getSymVA(uint32_t Type, typename ELFT::uint A, case R_SIZE: return Body.getSize<ELFT>() + A; case R_GOTREL: - return Body.getVA<ELFT>(A) - Out<ELFT>::Got->getVA(); + return Body.getVA<ELFT>(A) - In<ELFT>::Got->getVA(); + case R_GOTREL_FROM_END: + return Body.getVA<ELFT>(A) - In<ELFT>::Got->getVA() - + In<ELFT>::Got->getSize(); case R_RELAX_TLS_GD_TO_IE_END: case R_GOT_FROM_END: - return Body.getGotOffset<ELFT>() + A - - Out<ELFT>::Got->getNumEntries() * sizeof(uintX_t); + return Body.getGotOffset<ELFT>() + A - In<ELFT>::Got->getSize(); case R_RELAX_TLS_GD_TO_IE_ABS: case R_GOT: return Body.getGotVA<ELFT>() + A; @@ -232,11 +339,21 @@ static typename ELFT::uint getSymVA(uint32_t Type, typename ELFT::uint A, case R_GOT_PC: return Body.getGotVA<ELFT>() + A - P; case R_GOTONLY_PC: - return Out<ELFT>::Got->getVA() + A - P; + return In<ELFT>::Got->getVA() + A - P; + case R_GOTONLY_PC_FROM_END: + return In<ELFT>::Got->getVA() + A - P + In<ELFT>::Got->getSize(); case R_RELAX_TLS_LD_TO_LE: case R_RELAX_TLS_IE_TO_LE: case R_RELAX_TLS_GD_TO_LE: case R_TLS: + // A weak undefined TLS symbol resolves to the base of the TLS + // block, i.e. gets a value of zero. If we pass --gc-sections to + // lld and .tbss is not referenced, it gets reclaimed and we don't + // create a TLS program header. Therefore, we resolve this + // statically to zero. + if (Body.isTls() && (Body.isLazy() || Body.isUndefined()) && + Body.symbol()->isWeak()) + return 0; if (Target->TcbSize) return Body.getVA<ELFT>(A) + alignTo(Target->TcbSize, Out<ELFT>::TlsPhdr->p_align); @@ -253,18 +370,26 @@ static typename ELFT::uint getSymVA(uint32_t Type, typename ELFT::uint A, // If relocation against MIPS local symbol requires GOT entry, this entry // should be initialized by 'page address'. This address is high 16-bits // of sum the symbol's value and the addend. - return Out<ELFT>::Got->getMipsLocalPageOffset(Body.getVA<ELFT>(A)); + return In<ELFT>::MipsGot->getVA() + + In<ELFT>::MipsGot->getPageEntryOffset(Body, A) - + In<ELFT>::MipsGot->getGp(); case R_MIPS_GOT_OFF: + case R_MIPS_GOT_OFF32: // In case of MIPS if a GOT relocation has non-zero addend this addend // should be applied to the GOT entry content not to the GOT entry offset. // That is why we use separate expression type. - return Out<ELFT>::Got->getMipsGotOffset(Body, A); + return In<ELFT>::MipsGot->getVA() + + In<ELFT>::MipsGot->getBodyEntryOffset(Body, A) - + In<ELFT>::MipsGot->getGp(); + case R_MIPS_GOTREL: + return Body.getVA<ELFT>(A) - In<ELFT>::MipsGot->getGp(); case R_MIPS_TLSGD: - return Out<ELFT>::Got->getGlobalDynOffset(Body) + - Out<ELFT>::Got->getMipsTlsOffset() - MipsGPOffset; + return In<ELFT>::MipsGot->getVA() + In<ELFT>::MipsGot->getTlsOffset() + + In<ELFT>::MipsGot->getGlobalDynOffset(Body) - + In<ELFT>::MipsGot->getGp(); case R_MIPS_TLSLD: - return Out<ELFT>::Got->getTlsIndexOff() + - Out<ELFT>::Got->getMipsTlsOffset() - MipsGPOffset; + return In<ELFT>::MipsGot->getVA() + In<ELFT>::MipsGot->getTlsOffset() + + In<ELFT>::MipsGot->getTlsIndexOff() - In<ELFT>::MipsGot->getGp(); case R_PPC_OPD: { uint64_t SymVA = Body.getVA<ELFT>(A); // If we have an undefined weak symbol, we might get here with a symbol @@ -275,8 +400,8 @@ static typename ELFT::uint getSymVA(uint32_t Type, typename ELFT::uint A, if (Out<ELF64BE>::Opd) { // If this is a local call, and we currently have the address of a // function-descriptor, get the underlying code address instead. - uint64_t OpdStart = Out<ELF64BE>::Opd->getVA(); - uint64_t OpdEnd = OpdStart + Out<ELF64BE>::Opd->getSize(); + uint64_t OpdStart = Out<ELF64BE>::Opd->Addr; + uint64_t OpdEnd = OpdStart + Out<ELF64BE>::Opd->Size; bool InOpd = OpdStart <= SymVA && SymVA < OpdEnd; if (InOpd) SymVA = read64be(&Out<ELF64BE>::OpdBuf[SymVA - OpdStart]); @@ -284,10 +409,20 @@ static typename ELFT::uint getSymVA(uint32_t Type, typename ELFT::uint A, return SymVA - P; } case R_PC: + if (Body.isUndefined() && !Body.isLocal() && Body.symbol()->isWeak()) { + // On ARM and AArch64 a branch to an undefined weak resolves to the + // next instruction, otherwise the place. + if (Config->EMachine == EM_ARM) + return getARMUndefinedRelativeWeakVA(Type, A, P); + if (Config->EMachine == EM_AARCH64) + return getAArch64UndefinedRelativeWeakVA(Type, A, P); + } case R_RELAX_GOT_PC: return Body.getVA<ELFT>(A) - P; case R_PLT_PAGE_PC: case R_PAGE_PC: + if (Body.isUndefined() && !Body.isLocal() && Body.symbol()->isWeak()) + return getAArch64Page(A); return getAArch64Page(Body.getVA<ELFT>(A)) - getAArch64Page(P); } llvm_unreachable("Invalid expression"); @@ -303,7 +438,6 @@ static typename ELFT::uint getSymVA(uint32_t Type, typename ELFT::uint A, template <class ELFT> template <class RelTy> void InputSection<ELFT>::relocateNonAlloc(uint8_t *Buf, ArrayRef<RelTy> Rels) { - const unsigned Bits = sizeof(uintX_t) * 8; for (const RelTy &Rel : Rels) { uint32_t Type = Rel.getType(Config->Mips64EL); uintX_t Offset = this->getOffset(Rel.r_offset); @@ -314,13 +448,15 @@ void InputSection<ELFT>::relocateNonAlloc(uint8_t *Buf, ArrayRef<RelTy> Rels) { SymbolBody &Sym = this->File->getRelocTargetSym(Rel); if (Target->getRelExpr(Type, Sym) != R_ABS) { - error(this->getSectionName() + " has non-ABS reloc"); + error(this->getLocation(Offset) + ": has non-ABS reloc"); return; } - uintX_t AddrLoc = this->OutSec->getVA() + Offset; - uint64_t SymVA = - SignExtend64<Bits>(getSymVA<ELFT>(Type, Addend, AddrLoc, Sym, R_ABS)); + uintX_t AddrLoc = this->OutSec->Addr + Offset; + uint64_t SymVA = 0; + if (!Sym.isTls() || Out<ELFT>::TlsPhdr) + SymVA = SignExtend64<sizeof(uintX_t) * 8>( + getRelocTargetVA<ELFT>(Type, Addend, AddrLoc, Sym, R_ABS)); Target->relocateOne(BufLoc, Type, SymVA); } } @@ -331,78 +467,80 @@ void InputSectionBase<ELFT>::relocate(uint8_t *Buf, uint8_t *BufEnd) { // vector only for SHF_ALLOC'ed sections. For other sections, // we handle relocations directly here. auto *IS = dyn_cast<InputSection<ELFT>>(this); - if (IS && !(IS->Header->sh_flags & SHF_ALLOC)) { - for (const Elf_Shdr *RelSec : IS->RelocSections) { - if (RelSec->sh_type == SHT_RELA) - IS->relocateNonAlloc(Buf, IS->File->getObj().relas(RelSec)); - else - IS->relocateNonAlloc(Buf, IS->File->getObj().rels(RelSec)); - } + if (IS && !(IS->Flags & SHF_ALLOC)) { + if (IS->AreRelocsRela) + IS->relocateNonAlloc(Buf, IS->relas()); + else + IS->relocateNonAlloc(Buf, IS->rels()); return; } const unsigned Bits = sizeof(uintX_t) * 8; - for (const Relocation<ELFT> &Rel : Relocations) { - uintX_t Offset = Rel.InputSec->getOffset(Rel.Offset); + for (const Relocation &Rel : Relocations) { + uintX_t Offset = getOffset(Rel.Offset); uint8_t *BufLoc = Buf + Offset; uint32_t Type = Rel.Type; uintX_t A = Rel.Addend; - uintX_t AddrLoc = OutSec->getVA() + Offset; + uintX_t AddrLoc = OutSec->Addr + Offset; RelExpr Expr = Rel.Expr; - uint64_t SymVA = - SignExtend64<Bits>(getSymVA<ELFT>(Type, A, AddrLoc, *Rel.Sym, Expr)); + uint64_t TargetVA = SignExtend64<Bits>( + getRelocTargetVA<ELFT>(Type, A, AddrLoc, *Rel.Sym, Expr)); switch (Expr) { case R_RELAX_GOT_PC: case R_RELAX_GOT_PC_NOPIC: - Target->relaxGot(BufLoc, SymVA); + Target->relaxGot(BufLoc, TargetVA); break; case R_RELAX_TLS_IE_TO_LE: - Target->relaxTlsIeToLe(BufLoc, Type, SymVA); + Target->relaxTlsIeToLe(BufLoc, Type, TargetVA); break; case R_RELAX_TLS_LD_TO_LE: - Target->relaxTlsLdToLe(BufLoc, Type, SymVA); + Target->relaxTlsLdToLe(BufLoc, Type, TargetVA); break; case R_RELAX_TLS_GD_TO_LE: case R_RELAX_TLS_GD_TO_LE_NEG: - Target->relaxTlsGdToLe(BufLoc, Type, SymVA); + Target->relaxTlsGdToLe(BufLoc, Type, TargetVA); break; case R_RELAX_TLS_GD_TO_IE: case R_RELAX_TLS_GD_TO_IE_ABS: case R_RELAX_TLS_GD_TO_IE_PAGE_PC: case R_RELAX_TLS_GD_TO_IE_END: - Target->relaxTlsGdToIe(BufLoc, Type, SymVA); + Target->relaxTlsGdToIe(BufLoc, Type, TargetVA); break; case R_PPC_PLT_OPD: // Patch a nop (0x60000000) to a ld. if (BufLoc + 8 <= BufEnd && read32be(BufLoc + 4) == 0x60000000) write32be(BufLoc + 4, 0xe8410028); // ld %r2, 40(%r1) - // fallthrough + // fallthrough default: - Target->relocateOne(BufLoc, Type, SymVA); + Target->relocateOne(BufLoc, Type, TargetVA); break; } } } template <class ELFT> void InputSection<ELFT>::writeTo(uint8_t *Buf) { - if (this->Header->sh_type == SHT_NOBITS) + if (this->Type == SHT_NOBITS) return; - ELFFile<ELFT> &EObj = this->File->getObj(); + + if (auto *S = dyn_cast<SyntheticSection<ELFT>>(this)) { + S->writeTo(Buf + OutSecOff); + return; + } // If -r is given, then an InputSection may be a relocation section. - if (this->Header->sh_type == SHT_RELA) { - copyRelocations(Buf + OutSecOff, EObj.relas(this->Header)); + if (this->Type == SHT_RELA) { + copyRelocations(Buf + OutSecOff, this->template getDataAs<Elf_Rela>()); return; } - if (this->Header->sh_type == SHT_REL) { - copyRelocations(Buf + OutSecOff, EObj.rels(this->Header)); + if (this->Type == SHT_REL) { + copyRelocations(Buf + OutSecOff, this->template getDataAs<Elf_Rel>()); return; } // Copy section contents from source object file to output file. - ArrayRef<uint8_t> Data = this->getSectionData(); + ArrayRef<uint8_t> Data = this->Data; memcpy(Buf + OutSecOff, Data.data(), Data.size()); // Iterate over all relocation sections that apply to this section. @@ -431,15 +569,9 @@ void InputSection<ELFT>::replace(InputSection<ELFT> *Other) { } template <class ELFT> -SplitInputSection<ELFT>::SplitInputSection( - elf::ObjectFile<ELFT> *File, const Elf_Shdr *Header, - typename InputSectionBase<ELFT>::Kind SectionKind) - : InputSectionBase<ELFT>(File, Header, SectionKind) {} - -template <class ELFT> EhInputSection<ELFT>::EhInputSection(elf::ObjectFile<ELFT> *F, - const Elf_Shdr *Header) - : SplitInputSection<ELFT>(F, Header, InputSectionBase<ELFT>::EHFrame) { + const Elf_Shdr *Header, StringRef Name) + : InputSectionBase<ELFT>(F, Header, Name, InputSectionBase<ELFT>::EHFrame) { // Mark .eh_frame sections as live by default because there are // usually no relocations that point to .eh_frames. Otherwise, // the garbage collector would drop all .eh_frame sections. @@ -447,18 +579,54 @@ EhInputSection<ELFT>::EhInputSection(elf::ObjectFile<ELFT> *F, } template <class ELFT> -bool EhInputSection<ELFT>::classof(const InputSectionBase<ELFT> *S) { - return S->SectionKind == InputSectionBase<ELFT>::EHFrame; +bool EhInputSection<ELFT>::classof(const InputSectionData *S) { + return S->kind() == InputSectionBase<ELFT>::EHFrame; +} + +// Returns the index of the first relocation that points to a region between +// Begin and Begin+Size. +template <class IntTy, class RelTy> +static unsigned getReloc(IntTy Begin, IntTy Size, const ArrayRef<RelTy> &Rels, + unsigned &RelocI) { + // Start search from RelocI for fast access. That works because the + // relocations are sorted in .eh_frame. + for (unsigned N = Rels.size(); RelocI < N; ++RelocI) { + const RelTy &Rel = Rels[RelocI]; + if (Rel.r_offset < Begin) + continue; + + if (Rel.r_offset < Begin + Size) + return RelocI; + return -1; + } + return -1; } // .eh_frame is a sequence of CIE or FDE records. // This function splits an input section into records and returns them. +template <class ELFT> void EhInputSection<ELFT>::split() { + // Early exit if already split. + if (!this->Pieces.empty()) + return; + + if (this->NumRelocations) { + if (this->AreRelocsRela) + split(this->relas()); + else + split(this->rels()); + return; + } + split(makeArrayRef<typename ELFT::Rela>(nullptr, nullptr)); +} + template <class ELFT> -void EhInputSection<ELFT>::split() { - ArrayRef<uint8_t> Data = this->getSectionData(); +template <class RelTy> +void EhInputSection<ELFT>::split(ArrayRef<RelTy> Rels) { + ArrayRef<uint8_t> Data = this->Data; + unsigned RelI = 0; for (size_t Off = 0, End = Data.size(); Off != End;) { - size_t Size = readEhRecordSize<ELFT>(Data.slice(Off)); - this->Pieces.emplace_back(Off, Data.slice(Off, Size)); + size_t Size = readEhRecordSize<ELFT>(this, Off); + this->Pieces.emplace_back(Off, this, Size, getReloc(Off, Size, Rels, RelI)); // The empty record is the end marker. if (Size == 4) break; @@ -466,21 +634,6 @@ void EhInputSection<ELFT>::split() { } } -template <class ELFT> -typename ELFT::uint EhInputSection<ELFT>::getOffset(uintX_t Offset) const { - // The file crtbeginT.o has relocations pointing to the start of an empty - // .eh_frame that is known to be the first in the link. It does that to - // identify the start of the output .eh_frame. Handle this special case. - if (this->getSectionHdr()->sh_size == 0) - return Offset; - const SectionPiece *Piece = this->getSectionPiece(Offset); - if (Piece->OutputOff == size_t(-1)) - return -1; // Not in the output - - uintX_t Addend = Offset - Piece->InputOff; - return Piece->OutputOff + Addend; -} - static size_t findNull(ArrayRef<uint8_t> A, size_t EntSize) { // Optimize the common case. StringRef S((const char *)A.data(), A.size()); @@ -497,75 +650,96 @@ static size_t findNull(ArrayRef<uint8_t> A, size_t EntSize) { // Split SHF_STRINGS section. Such section is a sequence of // null-terminated strings. -static std::vector<SectionPiece> splitStrings(ArrayRef<uint8_t> Data, - size_t EntSize) { - std::vector<SectionPiece> V; +template <class ELFT> +void MergeInputSection<ELFT>::splitStrings(ArrayRef<uint8_t> Data, + size_t EntSize) { size_t Off = 0; + bool IsAlloc = this->Flags & SHF_ALLOC; while (!Data.empty()) { size_t End = findNull(Data, EntSize); if (End == StringRef::npos) - fatal("string is not null terminated"); + fatal(toString(this) + ": string is not null terminated"); size_t Size = End + EntSize; - V.emplace_back(Off, Data.slice(0, Size)); + Pieces.emplace_back(Off, !IsAlloc); + Hashes.push_back(hash_value(toStringRef(Data.slice(0, Size)))); Data = Data.slice(Size); Off += Size; } - return V; } // Split non-SHF_STRINGS section. Such section is a sequence of // fixed size records. -static std::vector<SectionPiece> splitNonStrings(ArrayRef<uint8_t> Data, - size_t EntSize) { - std::vector<SectionPiece> V; +template <class ELFT> +void MergeInputSection<ELFT>::splitNonStrings(ArrayRef<uint8_t> Data, + size_t EntSize) { size_t Size = Data.size(); assert((Size % EntSize) == 0); - for (unsigned I = 0, N = Size; I != N; I += EntSize) - V.emplace_back(I, Data.slice(I, EntSize)); - return V; + bool IsAlloc = this->Flags & SHF_ALLOC; + for (unsigned I = 0, N = Size; I != N; I += EntSize) { + Hashes.push_back(hash_value(toStringRef(Data.slice(I, EntSize)))); + Pieces.emplace_back(I, !IsAlloc); + } } template <class ELFT> MergeInputSection<ELFT>::MergeInputSection(elf::ObjectFile<ELFT> *F, - const Elf_Shdr *Header) - : SplitInputSection<ELFT>(F, Header, InputSectionBase<ELFT>::Merge) {} + const Elf_Shdr *Header, + StringRef Name) + : InputSectionBase<ELFT>(F, Header, Name, InputSectionBase<ELFT>::Merge) {} +// This function is called after we obtain a complete list of input sections +// that need to be linked. This is responsible to split section contents +// into small chunks for further processing. +// +// Note that this function is called from parallel_for_each. This must be +// thread-safe (i.e. no memory allocation from the pools). template <class ELFT> void MergeInputSection<ELFT>::splitIntoPieces() { - ArrayRef<uint8_t> Data = this->getSectionData(); - uintX_t EntSize = this->Header->sh_entsize; - if (this->Header->sh_flags & SHF_STRINGS) - this->Pieces = splitStrings(Data, EntSize); + ArrayRef<uint8_t> Data = this->Data; + uintX_t EntSize = this->Entsize; + if (this->Flags & SHF_STRINGS) + splitStrings(Data, EntSize); else - this->Pieces = splitNonStrings(Data, EntSize); + splitNonStrings(Data, EntSize); - if (Config->GcSections) + if (Config->GcSections && (this->Flags & SHF_ALLOC)) for (uintX_t Off : LiveOffsets) this->getSectionPiece(Off)->Live = true; } template <class ELFT> -bool MergeInputSection<ELFT>::classof(const InputSectionBase<ELFT> *S) { - return S->SectionKind == InputSectionBase<ELFT>::Merge; +bool MergeInputSection<ELFT>::classof(const InputSectionData *S) { + return S->kind() == InputSectionBase<ELFT>::Merge; } // Do binary search to get a section piece at a given input offset. template <class ELFT> -SectionPiece *SplitInputSection<ELFT>::getSectionPiece(uintX_t Offset) { - auto *This = static_cast<const SplitInputSection<ELFT> *>(this); +SectionPiece *MergeInputSection<ELFT>::getSectionPiece(uintX_t Offset) { + auto *This = static_cast<const MergeInputSection<ELFT> *>(this); return const_cast<SectionPiece *>(This->getSectionPiece(Offset)); } +template <class It, class T, class Compare> +static It fastUpperBound(It First, It Last, const T &Value, Compare Comp) { + size_t Size = std::distance(First, Last); + assert(Size != 0); + while (Size != 1) { + size_t H = Size / 2; + const It MI = First + H; + Size -= H; + First = Comp(Value, *MI) ? First : First + H; + } + return Comp(Value, *First) ? First : First + 1; +} + template <class ELFT> const SectionPiece * -SplitInputSection<ELFT>::getSectionPiece(uintX_t Offset) const { - ArrayRef<uint8_t> D = this->getSectionData(); - StringRef Data((const char *)D.data(), D.size()); - uintX_t Size = Data.size(); +MergeInputSection<ELFT>::getSectionPiece(uintX_t Offset) const { + uintX_t Size = this->Data.size(); if (Offset >= Size) - fatal("entry is past the end of the section"); + fatal(toString(this) + ": entry is past the end of the section"); // Find the element this offset points to. - auto I = std::upper_bound( + auto I = fastUpperBound( Pieces.begin(), Pieces.end(), Offset, [](const uintX_t &A, const SectionPiece &B) { return A < B.InputOff; }); --I; @@ -577,84 +751,31 @@ SplitInputSection<ELFT>::getSectionPiece(uintX_t Offset) const { // it is not just an addition to a base output offset. template <class ELFT> typename ELFT::uint MergeInputSection<ELFT>::getOffset(uintX_t Offset) const { + // Initialize OffsetMap lazily. + std::call_once(InitOffsetMap, [&] { + OffsetMap.reserve(Pieces.size()); + for (const SectionPiece &Piece : Pieces) + OffsetMap[Piece.InputOff] = Piece.OutputOff; + }); + + // Find a string starting at a given offset. auto It = OffsetMap.find(Offset); if (It != OffsetMap.end()) return It->second; + if (!this->Live) + return 0; + // If Offset is not at beginning of a section piece, it is not in the map. // In that case we need to search from the original section piece vector. const SectionPiece &Piece = *this->getSectionPiece(Offset); - assert(Piece.Live); + if (!Piece.Live) + return 0; + uintX_t Addend = Offset - Piece.InputOff; return Piece.OutputOff + Addend; } -// Create a map from input offsets to output offsets for all section pieces. -// It is called after finalize(). -template <class ELFT> void MergeInputSection<ELFT>::finalizePieces() { - OffsetMap.grow(this->Pieces.size()); - for (SectionPiece &Piece : this->Pieces) { - if (!Piece.Live) - continue; - if (Piece.OutputOff == size_t(-1)) { - // Offsets of tail-merged strings are computed lazily. - auto *OutSec = static_cast<MergeOutputSection<ELFT> *>(this->OutSec); - ArrayRef<uint8_t> D = Piece.data(); - StringRef S((const char *)D.data(), D.size()); - Piece.OutputOff = OutSec->getOffset(S); - } - OffsetMap[Piece.InputOff] = Piece.OutputOff; - } -} - -template <class ELFT> -MipsReginfoInputSection<ELFT>::MipsReginfoInputSection(elf::ObjectFile<ELFT> *F, - const Elf_Shdr *Hdr) - : InputSectionBase<ELFT>(F, Hdr, InputSectionBase<ELFT>::MipsReginfo) { - // Initialize this->Reginfo. - ArrayRef<uint8_t> D = this->getSectionData(); - if (D.size() != sizeof(Elf_Mips_RegInfo<ELFT>)) { - error("invalid size of .reginfo section"); - return; - } - Reginfo = reinterpret_cast<const Elf_Mips_RegInfo<ELFT> *>(D.data()); -} - -template <class ELFT> -bool MipsReginfoInputSection<ELFT>::classof(const InputSectionBase<ELFT> *S) { - return S->SectionKind == InputSectionBase<ELFT>::MipsReginfo; -} - -template <class ELFT> -MipsOptionsInputSection<ELFT>::MipsOptionsInputSection(elf::ObjectFile<ELFT> *F, - const Elf_Shdr *Hdr) - : InputSectionBase<ELFT>(F, Hdr, InputSectionBase<ELFT>::MipsOptions) { - // Find ODK_REGINFO option in the section's content. - ArrayRef<uint8_t> D = this->getSectionData(); - while (!D.empty()) { - if (D.size() < sizeof(Elf_Mips_Options<ELFT>)) { - error("invalid size of .MIPS.options section"); - break; - } - auto *O = reinterpret_cast<const Elf_Mips_Options<ELFT> *>(D.data()); - if (O->kind == ODK_REGINFO) { - Reginfo = &O->getRegInfo(); - break; - } - D = D.slice(O->size); - } -} - -template <class ELFT> -bool MipsOptionsInputSection<ELFT>::classof(const InputSectionBase<ELFT> *S) { - return S->SectionKind == InputSectionBase<ELFT>::MipsOptions; -} - -template bool elf::isDiscarded<ELF32LE>(InputSectionBase<ELF32LE> *); -template bool elf::isDiscarded<ELF32BE>(InputSectionBase<ELF32BE> *); -template bool elf::isDiscarded<ELF64LE>(InputSectionBase<ELF64LE> *); -template bool elf::isDiscarded<ELF64BE>(InputSectionBase<ELF64BE> *); - template class elf::InputSectionBase<ELF32LE>; template class elf::InputSectionBase<ELF32BE>; template class elf::InputSectionBase<ELF64LE>; @@ -665,11 +786,6 @@ template class elf::InputSection<ELF32BE>; template class elf::InputSection<ELF64LE>; template class elf::InputSection<ELF64BE>; -template class elf::SplitInputSection<ELF32LE>; -template class elf::SplitInputSection<ELF32BE>; -template class elf::SplitInputSection<ELF64LE>; -template class elf::SplitInputSection<ELF64BE>; - template class elf::EhInputSection<ELF32LE>; template class elf::EhInputSection<ELF32BE>; template class elf::EhInputSection<ELF64LE>; @@ -680,12 +796,7 @@ template class elf::MergeInputSection<ELF32BE>; template class elf::MergeInputSection<ELF64LE>; template class elf::MergeInputSection<ELF64BE>; -template class elf::MipsReginfoInputSection<ELF32LE>; -template class elf::MipsReginfoInputSection<ELF32BE>; -template class elf::MipsReginfoInputSection<ELF64LE>; -template class elf::MipsReginfoInputSection<ELF64BE>; - -template class elf::MipsOptionsInputSection<ELF32LE>; -template class elf::MipsOptionsInputSection<ELF32BE>; -template class elf::MipsOptionsInputSection<ELF64LE>; -template class elf::MipsOptionsInputSection<ELF64BE>; +template std::string lld::toString(const InputSectionBase<ELF32LE> *); +template std::string lld::toString(const InputSectionBase<ELF32BE> *); +template std::string lld::toString(const InputSectionBase<ELF64LE> *); +template std::string lld::toString(const InputSectionBase<ELF64BE> *); |
