diff options
Diffstat (limited to 'ELF/InputSection.cpp')
| -rw-r--r-- | ELF/InputSection.cpp | 461 |
1 files changed, 237 insertions, 224 deletions
diff --git a/ELF/InputSection.cpp b/ELF/InputSection.cpp index c6a539b8dfa5..02cad56ca508 100644 --- a/ELF/InputSection.cpp +++ b/ELF/InputSection.cpp @@ -10,21 +10,23 @@ #include "InputSection.h" #include "Config.h" #include "EhFrame.h" -#include "Error.h" #include "InputFiles.h" #include "LinkerScript.h" -#include "Memory.h" #include "OutputSections.h" #include "Relocations.h" +#include "Symbols.h" #include "SyntheticSections.h" #include "Target.h" #include "Thunks.h" +#include "lld/Common/ErrorHandler.h" +#include "lld/Common/Memory.h" #include "llvm/Object/Decompressor.h" #include "llvm/Support/Compiler.h" #include "llvm/Support/Compression.h" #include "llvm/Support/Endian.h" #include "llvm/Support/Path.h" #include "llvm/Support/Threading.h" +#include "llvm/Support/xxhash.h" #include <mutex> using namespace llvm; @@ -44,8 +46,34 @@ std::string lld::toString(const InputSectionBase *Sec) { return (toString(Sec->File) + ":(" + Sec->Name + ")").str(); } +DenseMap<SectionBase *, int> elf::buildSectionOrder() { + DenseMap<SectionBase *, int> SectionOrder; + if (Config->SymbolOrderingFile.empty()) + return SectionOrder; + + // Build a map from symbols to their priorities. Symbols that didn't + // appear in the symbol ordering file have the lowest priority 0. + // All explicitly mentioned symbols have negative (higher) priorities. + DenseMap<StringRef, int> SymbolOrder; + int Priority = -Config->SymbolOrderingFile.size(); + for (StringRef S : Config->SymbolOrderingFile) + SymbolOrder.insert({S, Priority++}); + + // Build a map from sections to their priorities. + for (InputFile *File : ObjectFiles) { + for (Symbol *Sym : File->getSymbols()) { + auto *D = dyn_cast<Defined>(Sym); + if (!D || !D->Section) + continue; + int &Priority = SectionOrder[D->Section]; + Priority = std::min(Priority, SymbolOrder.lookup(D->getName())); + } + } + return SectionOrder; +} + template <class ELFT> -static ArrayRef<uint8_t> getSectionContents(elf::ObjectFile<ELFT> *File, +static ArrayRef<uint8_t> getSectionContents(ObjFile<ELFT> *File, const typename ELFT::Shdr *Hdr) { if (!File || Hdr->sh_type == SHT_NOBITS) return makeArrayRef<uint8_t>(nullptr, Hdr->sh_size); @@ -59,9 +87,7 @@ InputSectionBase::InputSectionBase(InputFile *File, uint64_t Flags, StringRef Name, Kind SectionKind) : SectionBase(SectionKind, Name, Flags, Entsize, Alignment, Type, Info, Link), - File(File), Data(Data), Repl(this) { - Live = !Config->GcSections || !(Flags & SHF_ALLOC); - Assigned = false; + File(File), Data(Data) { NumRelocations = 0; AreRelocsRela = false; @@ -102,7 +128,7 @@ static uint64_t getType(uint64_t Type, StringRef Name) { } template <class ELFT> -InputSectionBase::InputSectionBase(elf::ObjectFile<ELFT> *File, +InputSectionBase::InputSectionBase(ObjFile<ELFT> *File, const typename ELFT::Shdr *Hdr, StringRef Name, Kind SectionKind) : InputSectionBase(File, getFlags(Hdr->sh_flags), @@ -160,7 +186,7 @@ uint64_t SectionBase::getOffset(uint64_t Offset) const { OutputSection *SectionBase::getOutputSection() { InputSection *Sec; if (auto *IS = dyn_cast<InputSection>(this)) - Sec = IS; + return IS->getParent(); else if (auto *MS = dyn_cast<MergeInputSection>(this)) Sec = MS->getParent(); else if (auto *EH = dyn_cast<EhInputSection>(this)) @@ -170,29 +196,23 @@ OutputSection *SectionBase::getOutputSection() { return Sec ? Sec->getParent() : nullptr; } -// Uncompress section contents. Note that this function is called -// from parallel_for_each, so it must be thread-safe. -void InputSectionBase::uncompress() { +// Uncompress section contents if required. Note that this function +// is called from parallelForEach, so it must be thread-safe. +void InputSectionBase::maybeUncompress() { + if (UncompressBuf || !Decompressor::isCompressedELFSection(Flags, Name)) + return; + Decompressor Dec = check(Decompressor::create(Name, toStringRef(Data), Config->IsLE, Config->Is64)); size_t Size = Dec.getDecompressedSize(); - char *OutputBuf; - { - static std::mutex Mu; - std::lock_guard<std::mutex> Lock(Mu); - OutputBuf = BAlloc.Allocate<char>(Size); - } - - if (Error E = Dec.decompress({OutputBuf, Size})) + UncompressBuf.reset(new char[Size]()); + if (Error E = Dec.decompress({UncompressBuf.get(), Size})) fatal(toString(this) + ": decompress failed: " + llvm::toString(std::move(E))); - this->Data = ArrayRef<uint8_t>((uint8_t *)OutputBuf, Size); - this->Flags &= ~(uint64_t)SHF_COMPRESSED; -} -uint64_t SectionBase::getOffset(const DefinedRegular &Sym) const { - return getOffset(Sym.Value); + this->Data = makeArrayRef((uint8_t *)UncompressBuf.get(), Size); + this->Flags &= ~(uint64_t)SHF_COMPRESSED; } InputSection *InputSectionBase::getLinkOrderDep() const { @@ -200,9 +220,9 @@ InputSection *InputSectionBase::getLinkOrderDep() const { InputSectionBase *L = File->getSections()[Link]; if (auto *IS = dyn_cast<InputSection>(L)) return IS; - error( - "Merge and .eh_frame sections are not supported with SHF_LINK_ORDER " + - toString(L)); + error("a section with SHF_LINK_ORDER should not refer a non-regular " + "section: " + + toString(L)); } return nullptr; } @@ -227,8 +247,8 @@ std::string InputSectionBase::getLocation(uint64_t Offset) { SrcFile = toString(File); // Find a function symbol that encloses a given location. - for (SymbolBody *B : getFile<ELFT>()->getSymbols()) - if (auto *D = dyn_cast<DefinedRegular>(B)) + for (Symbol *B : File->getSymbols()) + if (auto *D = dyn_cast<Defined>(B)) if (D->Section == this && D->Type == STT_FUNC) if (D->Value <= Offset && Offset < D->Value + D->Size) return SrcFile + ":(function " + toString(*D) + ")"; @@ -237,31 +257,40 @@ std::string InputSectionBase::getLocation(uint64_t Offset) { return (SrcFile + ":(" + Name + "+0x" + utohexstr(Offset) + ")").str(); } -// Returns a source location string. This function is intended to be -// used for constructing an error message. The returned message looks -// like this: +// Concatenates arguments to construct a string representing an error location. +static std::string createFileLineMsg(StringRef Path, unsigned Line) { + std::string Filename = path::filename(Path); + std::string Lineno = ":" + std::to_string(Line); + if (Filename == Path) + return Filename + Lineno; + return Filename + Lineno + " (" + Path.str() + Lineno + ")"; +} + +// This function is intended to be used for constructing an error message. +// The returned message looks like this: // // foo.c:42 (/home/alice/possibly/very/long/path/foo.c:42) // -// Returns an empty string if there's no way to get line info. -template <class ELFT> std::string InputSectionBase::getSrcMsg(uint64_t Offset) { +// Returns an empty string if there's no way to get line info. +template <class ELFT> +std::string InputSectionBase::getSrcMsg(const Symbol &Sym, uint64_t Offset) { // Synthetic sections don't have input files. - elf::ObjectFile<ELFT> *File = getFile<ELFT>(); + ObjFile<ELFT> *File = getFile<ELFT>(); if (!File) return ""; - Optional<DILineInfo> Info = File->getDILineInfo(this, Offset); + // In DWARF, functions and variables are stored to different places. + // First, lookup a function for a given offset. + if (Optional<DILineInfo> Info = File->getDILineInfo(this, Offset)) + return createFileLineMsg(Info->FileName, Info->Line); - // File->SourceFile contains STT_FILE symbol, and that is a last resort. - if (!Info) - return File->SourceFile; + // If it failed, lookup again as a variable. + if (Optional<std::pair<std::string, unsigned>> FileLine = + File->getVariableLoc(Sym.getName())) + return createFileLineMsg(FileLine->first, FileLine->second); - std::string Path = Info->FileName; - std::string Filename = path::filename(Path); - std::string Lineno = ":" + std::to_string(Info->Line); - if (Filename == Path) - return Filename + Lineno; - return Filename + Lineno + " (" + Path + Lineno + ")"; + // File->SourceFile contains STT_FILE symbol, and that is a last resort. + return File->SourceFile; } // Returns a filename string along with an optional section name. This @@ -273,11 +302,10 @@ template <class ELFT> std::string InputSectionBase::getSrcMsg(uint64_t Offset) { // or // // path/to/foo.o:(function bar) in archive path/to/bar.a -template <class ELFT> std::string InputSectionBase::getObjMsg(uint64_t Off) { +std::string InputSectionBase::getObjMsg(uint64_t Off) { // Synthetic sections don't have input files. - elf::ObjectFile<ELFT> *File = getFile<ELFT>(); if (!File) - return ("(internal):(" + Name + "+0x" + utohexstr(Off) + ")").str(); + return ("<internal>:(" + Name + "+0x" + utohexstr(Off) + ")").str(); std::string Filename = File->getName(); std::string Archive; @@ -285,8 +313,8 @@ template <class ELFT> std::string InputSectionBase::getObjMsg(uint64_t Off) { Archive = (" in archive " + File->ArchiveName).str(); // Find a symbol that encloses a given location. - for (SymbolBody *B : getFile<ELFT>()->getSymbols()) - if (auto *D = dyn_cast<DefinedRegular>(B)) + for (Symbol *B : File->getSymbols()) + if (auto *D = dyn_cast<Defined>(B)) if (D->Section == this && D->Value <= Off && Off < D->Value + D->Size) return Filename + ":(" + toString(*D) + ")" + Archive; @@ -295,7 +323,7 @@ template <class ELFT> std::string InputSectionBase::getObjMsg(uint64_t Off) { .str(); } -InputSectionBase InputSectionBase::Discarded; +InputSection InputSection::Discarded(0, 0, 0, ArrayRef<uint8_t>(), ""); InputSection::InputSection(uint64_t Flags, uint32_t Type, uint32_t Alignment, ArrayRef<uint8_t> Data, StringRef Name, Kind K) @@ -304,8 +332,8 @@ InputSection::InputSection(uint64_t Flags, uint32_t Type, uint32_t Alignment, Name, K) {} template <class ELFT> -InputSection::InputSection(elf::ObjectFile<ELFT> *F, - const typename ELFT::Shdr *Header, StringRef Name) +InputSection::InputSection(ObjFile<ELFT> *F, const typename ELFT::Shdr *Header, + StringRef Name) : InputSectionBase(F, Header, Name, InputSectionBase::Regular) {} bool InputSection::classof(const SectionBase *S) { @@ -313,10 +341,6 @@ bool InputSection::classof(const SectionBase *S) { S->kind() == SectionBase::Synthetic; } -bool InputSectionBase::classof(const SectionBase *S) { - return S->kind() != Output; -} - OutputSection *InputSection::getParent() const { return cast_or_null<OutputSection>(Parent); } @@ -349,15 +373,11 @@ InputSectionBase *InputSection::getRelocatedSection() { // for each relocation. So we copy relocations one by one. template <class ELFT, class RelTy> void InputSection::copyRelocations(uint8_t *Buf, ArrayRef<RelTy> Rels) { - InputSectionBase *RelocatedSection = getRelocatedSection(); + InputSectionBase *Sec = getRelocatedSection(); - // Loop is slow and have complexity O(N*M), where N - amount of - // relocations and M - amount of symbols in symbol table. - // That happens because getSymbolIndex(...) call below performs - // simple linear search. for (const RelTy &Rel : Rels) { - uint32_t Type = Rel.getType(Config->IsMips64EL); - SymbolBody &Body = this->getFile<ELFT>()->getRelocTargetSym(Rel); + RelType Type = Rel.getType(Config->IsMips64EL); + Symbol &Sym = this->getFile<ELFT>()->getRelocTargetSym(Rel); auto *P = reinterpret_cast<typename ELFT::Rela *>(Buf); Buf += sizeof(RelTy); @@ -367,12 +387,11 @@ void InputSection::copyRelocations(uint8_t *Buf, ArrayRef<RelTy> Rels) { // Output section VA is zero for -r, so r_offset is an offset within the // section, but for --emit-relocs it is an virtual address. - P->r_offset = RelocatedSection->getOutputSection()->Addr + - RelocatedSection->getOffset(Rel.r_offset); - P->setSymbolAndType(InX::SymTab->getSymbolIndex(&Body), Type, + P->r_offset = Sec->getOutputSection()->Addr + Sec->getOffset(Rel.r_offset); + P->setSymbolAndType(InX::SymTab->getSymbolIndex(&Sym), Type, Config->IsMips64EL); - if (Body.Type == STT_SECTION) { + if (Sym.Type == STT_SECTION) { // We combine multiple section symbols into only one per // section. This means we have to update the addend. That is // trivial for Elf_Rela, but for Elf_Rel we have to write to the @@ -382,19 +401,25 @@ void InputSection::copyRelocations(uint8_t *Buf, ArrayRef<RelTy> Rels) { // avoid having to parse and recreate .eh_frame, we just replace any // relocation in it pointing to discarded sections with R_*_NONE, which // hopefully creates a frame that is ignored at runtime. - SectionBase *Section = cast<DefinedRegular>(Body).Section; + auto *D = dyn_cast<Defined>(&Sym); + if (!D) { + error("STT_SECTION symbol should be defined"); + continue; + } + SectionBase *Section = D->Section; if (Section == &InputSection::Discarded) { P->setSymbolAndType(0, 0, false); continue; } if (Config->IsRela) { - P->r_addend += Body.getVA() - Section->getOutputSection()->Addr; + P->r_addend = + Sym.getVA(getAddend<ELFT>(Rel)) - Section->getOutputSection()->Addr; } else if (Config->Relocatable) { - const uint8_t *BufLoc = RelocatedSection->Data.begin() + Rel.r_offset; - RelocatedSection->Relocations.push_back( - {R_ABS, Type, Rel.r_offset, Target->getImplicitAddend(BufLoc, Type), - &Body}); + const uint8_t *BufLoc = Sec->Data.begin() + Rel.r_offset; + Sec->Relocations.push_back({R_ABS, Type, Rel.r_offset, + Target->getImplicitAddend(BufLoc, Type), + &Sym}); } } @@ -406,7 +431,7 @@ void InputSection::copyRelocations(uint8_t *Buf, ArrayRef<RelTy> Rels) { // this context is the address of the place P. A further special case is that // branch relocations to an undefined weak reference resolve to the next // instruction. -static uint32_t getARMUndefinedRelativeWeakVA(uint32_t Type, uint32_t A, +static uint32_t getARMUndefinedRelativeWeakVA(RelType Type, uint32_t A, uint32_t P) { switch (Type) { // Unresolved branch relocations to weak references resolve to next @@ -453,6 +478,7 @@ static uint64_t getAArch64UndefinedRelativeWeakVA(uint64_t Type, uint64_t A, case R_AARCH64_PREL32: case R_AARCH64_PREL64: case R_AARCH64_ADR_PREL_LO21: + case R_AARCH64_LD_PREL_LO19: return P + A; } llvm_unreachable("AArch64 pc-relative relocation expected\n"); @@ -461,53 +487,55 @@ static uint64_t getAArch64UndefinedRelativeWeakVA(uint64_t Type, uint64_t A, // ARM SBREL relocations are of the form S + A - B where B is the static base // The ARM ABI defines base to be "addressing origin of the output segment // defining the symbol S". We defined the "addressing origin"/static base to be -// the base of the PT_LOAD segment containing the Body. +// the base of the PT_LOAD segment containing the Sym. // The procedure call standard only defines a Read Write Position Independent // RWPI variant so in practice we should expect the static base to be the base // of the RW segment. -static uint64_t getARMStaticBase(const SymbolBody &Body) { - OutputSection *OS = Body.getOutputSection(); - if (!OS || !OS->FirstInPtLoad) - fatal("SBREL relocation to " + Body.getName() + " without static base"); - return OS->FirstInPtLoad->Addr; +static uint64_t getARMStaticBase(const Symbol &Sym) { + OutputSection *OS = Sym.getOutputSection(); + if (!OS || !OS->PtLoad || !OS->PtLoad->FirstSec) + fatal("SBREL relocation to " + Sym.getName() + " without static base"); + return OS->PtLoad->FirstSec->Addr; } -static uint64_t getRelocTargetVA(uint32_t Type, int64_t A, uint64_t P, - const SymbolBody &Body, RelExpr Expr) { +static uint64_t getRelocTargetVA(RelType Type, int64_t A, uint64_t P, + const Symbol &Sym, RelExpr Expr) { switch (Expr) { + case R_INVALID: + return 0; case R_ABS: case R_RELAX_GOT_PC_NOPIC: - return Body.getVA(A); + return Sym.getVA(A); case R_ARM_SBREL: - return Body.getVA(A) - getARMStaticBase(Body); + return Sym.getVA(A) - getARMStaticBase(Sym); case R_GOT: case R_RELAX_TLS_GD_TO_IE_ABS: - return Body.getGotVA() + A; + return Sym.getGotVA() + A; case R_GOTONLY_PC: return InX::Got->getVA() + A - P; case R_GOTONLY_PC_FROM_END: return InX::Got->getVA() + A - P + InX::Got->getSize(); case R_GOTREL: - return Body.getVA(A) - InX::Got->getVA(); + return Sym.getVA(A) - InX::Got->getVA(); case R_GOTREL_FROM_END: - return Body.getVA(A) - InX::Got->getVA() - InX::Got->getSize(); + return Sym.getVA(A) - InX::Got->getVA() - InX::Got->getSize(); case R_GOT_FROM_END: case R_RELAX_TLS_GD_TO_IE_END: - return Body.getGotOffset() + A - InX::Got->getSize(); + return Sym.getGotOffset() + A - InX::Got->getSize(); case R_GOT_OFF: - return Body.getGotOffset() + A; + return Sym.getGotOffset() + A; case R_GOT_PAGE_PC: case R_RELAX_TLS_GD_TO_IE_PAGE_PC: - return getAArch64Page(Body.getGotVA() + A) - getAArch64Page(P); + return getAArch64Page(Sym.getGotVA() + A) - getAArch64Page(P); case R_GOT_PC: case R_RELAX_TLS_GD_TO_IE: - return Body.getGotVA() + A - P; + return Sym.getGotVA() + A - P; case R_HINT: case R_NONE: case R_TLSDESC_CALL: llvm_unreachable("cannot relocate hint relocs"); case R_MIPS_GOTREL: - return Body.getVA(A) - InX::MipsGot->getGp(); + return Sym.getVA(A) - InX::MipsGot->getGp(); case R_MIPS_GOT_GP: return InX::MipsGot->getGp() + A; case R_MIPS_GOT_GP_PC: { @@ -515,42 +543,47 @@ static uint64_t getRelocTargetVA(uint32_t Type, int64_t A, uint64_t P, // is _gp_disp symbol. In that case we should use the following // formula for calculation "AHL + GP - P + 4". For details see p. 4-19 at // ftp://www.linux-mips.org/pub/linux/mips/doc/ABI/mipsabi.pdf + // microMIPS variants of these relocations use slightly different + // expressions: AHL + GP - P + 3 for %lo() and AHL + GP - P - 1 for %hi() + // to correctly handle less-sugnificant bit of the microMIPS symbol. uint64_t V = InX::MipsGot->getGp() + A - P; - if (Type == R_MIPS_LO16) + if (Type == R_MIPS_LO16 || Type == R_MICROMIPS_LO16) V += 4; + if (Type == R_MICROMIPS_LO16 || Type == R_MICROMIPS_HI16) + V -= 1; return V; } case R_MIPS_GOT_LOCAL_PAGE: // 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 InX::MipsGot->getVA() + InX::MipsGot->getPageEntryOffset(Body, A) - + return InX::MipsGot->getVA() + InX::MipsGot->getPageEntryOffset(Sym, A) - InX::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 InX::MipsGot->getVA() + InX::MipsGot->getBodyEntryOffset(Body, A) - + return InX::MipsGot->getVA() + InX::MipsGot->getSymEntryOffset(Sym, A) - InX::MipsGot->getGp(); case R_MIPS_TLSGD: return InX::MipsGot->getVA() + InX::MipsGot->getTlsOffset() + - InX::MipsGot->getGlobalDynOffset(Body) - InX::MipsGot->getGp(); + InX::MipsGot->getGlobalDynOffset(Sym) - InX::MipsGot->getGp(); case R_MIPS_TLSLD: return InX::MipsGot->getVA() + InX::MipsGot->getTlsOffset() + InX::MipsGot->getTlsIndexOff() - InX::MipsGot->getGp(); case R_PAGE_PC: case R_PLT_PAGE_PC: { uint64_t Dest; - if (Body.isUndefined() && !Body.isLocal() && Body.symbol()->isWeak()) + if (Sym.isUndefWeak()) Dest = getAArch64Page(A); else - Dest = getAArch64Page(Body.getVA(A)); + Dest = getAArch64Page(Sym.getVA(A)); return Dest - getAArch64Page(P); } case R_PC: { uint64_t Dest; - if (Body.isUndefined() && !Body.isLocal() && Body.symbol()->isWeak()) { + if (Sym.isUndefWeak()) { // On ARM and AArch64 a branch to an undefined weak resolves to the // next instruction, otherwise the place. if (Config->EMachine == EM_ARM) @@ -558,19 +591,19 @@ static uint64_t getRelocTargetVA(uint32_t Type, int64_t A, uint64_t P, else if (Config->EMachine == EM_AARCH64) Dest = getAArch64UndefinedRelativeWeakVA(Type, A, P); else - Dest = Body.getVA(A); + Dest = Sym.getVA(A); } else { - Dest = Body.getVA(A); + Dest = Sym.getVA(A); } return Dest - P; } case R_PLT: - return Body.getPltVA() + A; + return Sym.getPltVA() + A; case R_PLT_PC: case R_PPC_PLT_OPD: - return Body.getPltVA() + A - P; + return Sym.getPltVA() + A - P; case R_PPC_OPD: { - uint64_t SymVA = Body.getVA(A); + uint64_t SymVA = Sym.getVA(A); // If we have an undefined weak symbol, we might get here with a symbol // address of zero. That could overflow, but the code must be unreachable, // so don't bother doing anything at all. @@ -590,7 +623,7 @@ static uint64_t getRelocTargetVA(uint32_t Type, int64_t A, uint64_t P, case R_PPC_TOC: return getPPC64TocBase() + A; case R_RELAX_GOT_PC: - return Body.getVA(A) - P; + return Sym.getVA(A) - P; case R_RELAX_TLS_GD_TO_LE: case R_RELAX_TLS_IE_TO_LE: case R_RELAX_TLS_LD_TO_LE: @@ -600,26 +633,25 @@ static uint64_t getRelocTargetVA(uint32_t Type, int64_t A, uint64_t P, // 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()) + if (Sym.isTls() && Sym.isUndefWeak()) return 0; if (Target->TcbSize) - return Body.getVA(A) + alignTo(Target->TcbSize, Out::TlsPhdr->p_align); - return Body.getVA(A) - Out::TlsPhdr->p_memsz; + return Sym.getVA(A) + alignTo(Target->TcbSize, Out::TlsPhdr->p_align); + return Sym.getVA(A) - Out::TlsPhdr->p_memsz; case R_RELAX_TLS_GD_TO_LE_NEG: case R_NEG_TLS: - return Out::TlsPhdr->p_memsz - Body.getVA(A); + return Out::TlsPhdr->p_memsz - Sym.getVA(A); case R_SIZE: - return A; // Body.getSize was already folded into the addend. + return A; // Sym.getSize was already folded into the addend. case R_TLSDESC: - return InX::Got->getGlobalDynAddr(Body) + A; + return InX::Got->getGlobalDynAddr(Sym) + A; case R_TLSDESC_PAGE: - return getAArch64Page(InX::Got->getGlobalDynAddr(Body) + A) - + return getAArch64Page(InX::Got->getGlobalDynAddr(Sym) + A) - getAArch64Page(P); case R_TLSGD: - return InX::Got->getGlobalDynOffset(Body) + A - InX::Got->getSize(); + return InX::Got->getGlobalDynOffset(Sym) + A - InX::Got->getSize(); case R_TLSGD_PC: - return InX::Got->getGlobalDynAddr(Body) + A - P; + return InX::Got->getGlobalDynAddr(Sym) + A - P; case R_TLSLD: return InX::Got->getTlsIndexOff() + A - InX::Got->getSize(); case R_TLSLD_PC: @@ -637,64 +669,62 @@ static uint64_t getRelocTargetVA(uint32_t Type, int64_t A, uint64_t P, // function as a performance optimization. template <class ELFT, class RelTy> void InputSection::relocateNonAlloc(uint8_t *Buf, ArrayRef<RelTy> Rels) { + const unsigned Bits = sizeof(typename ELFT::uint) * 8; + for (const RelTy &Rel : Rels) { - uint32_t Type = Rel.getType(Config->IsMips64EL); + RelType Type = Rel.getType(Config->IsMips64EL); uint64_t Offset = getOffset(Rel.r_offset); uint8_t *BufLoc = Buf + Offset; int64_t Addend = getAddend<ELFT>(Rel); if (!RelTy::IsRela) Addend += Target->getImplicitAddend(BufLoc, Type); - SymbolBody &Sym = this->getFile<ELFT>()->getRelocTargetSym(Rel); + Symbol &Sym = this->getFile<ELFT>()->getRelocTargetSym(Rel); RelExpr Expr = Target->getRelExpr(Type, Sym, BufLoc); if (Expr == R_NONE) continue; if (Expr != R_ABS) { - error(this->getLocation<ELFT>(Offset) + ": has non-ABS reloc"); + // GCC 8.0 or earlier have a bug that it emits R_386_GOTPC relocations + // against _GLOBAL_OFFSET_TABLE for .debug_info. The bug seems to have + // been fixed in 2017: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82630, + // but we need to keep this bug-compatible code for a while. + if (Config->EMachine == EM_386 && Type == R_386_GOTPC) + continue; + + error(this->getLocation<ELFT>(Offset) + ": has non-ABS relocation " + + toString(Type) + " against symbol '" + toString(Sym) + "'"); return; } - uint64_t AddrLoc = getParent()->Addr + Offset; - uint64_t SymVA = 0; - if (!Sym.isTls() || Out::TlsPhdr) - SymVA = SignExtend64<sizeof(typename ELFT::uint) * 8>( - getRelocTargetVA(Type, Addend, AddrLoc, Sym, R_ABS)); - Target->relocateOne(BufLoc, Type, SymVA); + if (Sym.isTls() && !Out::TlsPhdr) + Target->relocateOne(BufLoc, Type, 0); + else + Target->relocateOne(BufLoc, Type, SignExtend64<Bits>(Sym.getVA(Addend))); } } -template <class ELFT> elf::ObjectFile<ELFT> *InputSectionBase::getFile() const { - return cast_or_null<elf::ObjectFile<ELFT>>(File); -} - template <class ELFT> void InputSectionBase::relocate(uint8_t *Buf, uint8_t *BufEnd) { - if (Flags & SHF_ALLOC) + if (Flags & SHF_ALLOC) { relocateAlloc(Buf, BufEnd); - else - relocateNonAlloc<ELFT>(Buf, BufEnd); -} + return; + } -template <class ELFT> -void InputSectionBase::relocateNonAlloc(uint8_t *Buf, uint8_t *BufEnd) { - // scanReloc function in Writer.cpp constructs Relocations - // vector only for SHF_ALLOC'ed sections. For other sections, - // we handle relocations directly here. - auto *IS = cast<InputSection>(this); - assert(!(IS->Flags & SHF_ALLOC)); - if (IS->AreRelocsRela) - IS->relocateNonAlloc<ELFT>(Buf, IS->template relas<ELFT>()); + auto *Sec = cast<InputSection>(this); + if (Sec->AreRelocsRela) + Sec->relocateNonAlloc<ELFT>(Buf, Sec->template relas<ELFT>()); else - IS->relocateNonAlloc<ELFT>(Buf, IS->template rels<ELFT>()); + Sec->relocateNonAlloc<ELFT>(Buf, Sec->template rels<ELFT>()); } void InputSectionBase::relocateAlloc(uint8_t *Buf, uint8_t *BufEnd) { assert(Flags & SHF_ALLOC); const unsigned Bits = Config->Wordsize * 8; + for (const Relocation &Rel : Relocations) { uint64_t Offset = getOffset(Rel.Offset); uint8_t *BufLoc = Buf + Offset; - uint32_t Type = Rel.Type; + RelType Type = Rel.Type; uint64_t AddrLoc = getOutputSection()->Addr + Offset; RelExpr Expr = Rel.Expr; @@ -776,24 +806,15 @@ void InputSection::replace(InputSection *Other) { } template <class ELFT> -EhInputSection::EhInputSection(elf::ObjectFile<ELFT> *F, +EhInputSection::EhInputSection(ObjFile<ELFT> *F, const typename ELFT::Shdr *Header, StringRef Name) - : InputSectionBase(F, Header, Name, InputSectionBase::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. - this->Live = true; -} + : InputSectionBase(F, Header, Name, InputSectionBase::EHFrame) {} SyntheticSection *EhInputSection::getParent() const { return cast_or_null<SyntheticSection>(Parent); } -bool EhInputSection::classof(const SectionBase *S) { - return S->kind() == InputSectionBase::EHFrame; -} - // Returns the index of the first relocation that points to a region between // Begin and Begin+Size. template <class IntTy, class RelTy> @@ -820,14 +841,10 @@ template <class ELFT> void EhInputSection::split() { if (!this->Pieces.empty()) return; - if (this->NumRelocations) { - if (this->AreRelocsRela) - split<ELFT>(this->relas<ELFT>()); - else - split<ELFT>(this->rels<ELFT>()); - return; - } - split<ELFT>(makeArrayRef<typename ELFT::Rela>(nullptr, nullptr)); + if (this->AreRelocsRela) + split<ELFT>(this->relas<ELFT>()); + else + split<ELFT>(this->rels<ELFT>()); } template <class ELFT, class RelTy> @@ -835,7 +852,7 @@ void EhInputSection::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>(this, Off); + size_t Size = readEhRecordSize(this, Off); this->Pieces.emplace_back(Off, this, Size, getReloc(Off, Size, Rels, RelI)); // The empty record is the end marker. if (Size == 4) @@ -844,9 +861,8 @@ void EhInputSection::split(ArrayRef<RelTy> Rels) { } } -static size_t findNull(ArrayRef<uint8_t> A, size_t EntSize) { +static size_t findNull(StringRef S, size_t EntSize) { // Optimize the common case. - StringRef S((const char *)A.data(), A.size()); if (EntSize == 1) return S.find(0); @@ -867,14 +883,16 @@ SyntheticSection *MergeInputSection::getParent() const { void MergeInputSection::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); + StringRef S = toStringRef(Data); + + while (!S.empty()) { + size_t End = findNull(S, EntSize); if (End == StringRef::npos) fatal(toString(this) + ": string is not null terminated"); size_t Size = End + EntSize; - Pieces.emplace_back(Off, !IsAlloc); - Hashes.push_back(hash_value(toStringRef(Data.slice(0, Size)))); - Data = Data.slice(Size); + + Pieces.emplace_back(Off, xxHash64(S.substr(0, Size)), !IsAlloc); + S = S.substr(Size); Off += Size; } } @@ -886,41 +904,43 @@ void MergeInputSection::splitNonStrings(ArrayRef<uint8_t> Data, size_t Size = Data.size(); assert((Size % EntSize) == 0); 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); - } + + for (size_t I = 0; I != Size; I += EntSize) + Pieces.emplace_back(I, xxHash64(toStringRef(Data.slice(I, EntSize))), + !IsAlloc); } template <class ELFT> -MergeInputSection::MergeInputSection(elf::ObjectFile<ELFT> *F, +MergeInputSection::MergeInputSection(ObjFile<ELFT> *F, const typename ELFT::Shdr *Header, StringRef Name) - : InputSectionBase(F, Header, Name, InputSectionBase::Merge) {} + : InputSectionBase(F, Header, Name, InputSectionBase::Merge) { + // In order to reduce memory allocation, we assume that mergeable + // sections are smaller than 4 GiB, which is not an unreasonable + // assumption as of 2017. + if (Data.size() > UINT32_MAX) + error(toString(this) + ": section too large"); +} // 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 +// Note that this function is called from parallelForEach. This must be // thread-safe (i.e. no memory allocation from the pools). void MergeInputSection::splitIntoPieces() { - ArrayRef<uint8_t> Data = this->Data; - uint64_t EntSize = this->Entsize; + assert(Pieces.empty()); + if (this->Flags & SHF_STRINGS) - splitStrings(Data, EntSize); + splitStrings(Data, Entsize); else - splitNonStrings(Data, EntSize); + splitNonStrings(Data, Entsize); if (Config->GcSections && (this->Flags & SHF_ALLOC)) for (uint64_t Off : LiveOffsets) this->getSectionPiece(Off)->Live = true; } -bool MergeInputSection::classof(const SectionBase *S) { - return S->kind() == InputSectionBase::Merge; -} - // Do binary search to get a section piece at a given input offset. SectionPiece *MergeInputSection::getSectionPiece(uint64_t Offset) { auto *This = static_cast<const MergeInputSection *>(this); @@ -941,8 +961,7 @@ static It fastUpperBound(It First, It Last, const T &Value, Compare Comp) { } const SectionPiece *MergeInputSection::getSectionPiece(uint64_t Offset) const { - uint64_t Size = this->Data.size(); - if (Offset >= Size) + if (Data.size() <= Offset) fatal(toString(this) + ": entry is past the end of the section"); // Find the element this offset points to. @@ -957,20 +976,20 @@ const SectionPiece *MergeInputSection::getSectionPiece(uint64_t Offset) const { // Because contents of a mergeable section is not contiguous in output, // it is not just an addition to a base output offset. uint64_t MergeInputSection::getOffset(uint64_t Offset) const { + if (!Live) + return 0; + // Initialize OffsetMap lazily. llvm::call_once(InitOffsetMap, [&] { OffsetMap.reserve(Pieces.size()); - for (const SectionPiece &Piece : Pieces) - OffsetMap[Piece.InputOff] = Piece.OutputOff; + for (size_t I = 0; I < Pieces.size(); ++I) + OffsetMap[Pieces[I].InputOff] = I; }); // 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; + return Pieces[It->second].OutputOff; // 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. @@ -982,56 +1001,50 @@ uint64_t MergeInputSection::getOffset(uint64_t Offset) const { return Piece.OutputOff + Addend; } -template InputSection::InputSection(elf::ObjectFile<ELF32LE> *, - const ELF32LE::Shdr *, StringRef); -template InputSection::InputSection(elf::ObjectFile<ELF32BE> *, - const ELF32BE::Shdr *, StringRef); -template InputSection::InputSection(elf::ObjectFile<ELF64LE> *, - const ELF64LE::Shdr *, StringRef); -template InputSection::InputSection(elf::ObjectFile<ELF64BE> *, - const ELF64BE::Shdr *, StringRef); +template InputSection::InputSection(ObjFile<ELF32LE> *, const ELF32LE::Shdr *, + StringRef); +template InputSection::InputSection(ObjFile<ELF32BE> *, const ELF32BE::Shdr *, + StringRef); +template InputSection::InputSection(ObjFile<ELF64LE> *, const ELF64LE::Shdr *, + StringRef); +template InputSection::InputSection(ObjFile<ELF64BE> *, const ELF64BE::Shdr *, + StringRef); template std::string InputSectionBase::getLocation<ELF32LE>(uint64_t); template std::string InputSectionBase::getLocation<ELF32BE>(uint64_t); template std::string InputSectionBase::getLocation<ELF64LE>(uint64_t); template std::string InputSectionBase::getLocation<ELF64BE>(uint64_t); -template std::string InputSectionBase::getSrcMsg<ELF32LE>(uint64_t); -template std::string InputSectionBase::getSrcMsg<ELF32BE>(uint64_t); -template std::string InputSectionBase::getSrcMsg<ELF64LE>(uint64_t); -template std::string InputSectionBase::getSrcMsg<ELF64BE>(uint64_t); - -template std::string InputSectionBase::getObjMsg<ELF32LE>(uint64_t); -template std::string InputSectionBase::getObjMsg<ELF32BE>(uint64_t); -template std::string InputSectionBase::getObjMsg<ELF64LE>(uint64_t); -template std::string InputSectionBase::getObjMsg<ELF64BE>(uint64_t); +template std::string InputSectionBase::getSrcMsg<ELF32LE>(const Symbol &, + uint64_t); +template std::string InputSectionBase::getSrcMsg<ELF32BE>(const Symbol &, + uint64_t); +template std::string InputSectionBase::getSrcMsg<ELF64LE>(const Symbol &, + uint64_t); +template std::string InputSectionBase::getSrcMsg<ELF64BE>(const Symbol &, + uint64_t); template void InputSection::writeTo<ELF32LE>(uint8_t *); template void InputSection::writeTo<ELF32BE>(uint8_t *); template void InputSection::writeTo<ELF64LE>(uint8_t *); template void InputSection::writeTo<ELF64BE>(uint8_t *); -template elf::ObjectFile<ELF32LE> *InputSectionBase::getFile<ELF32LE>() const; -template elf::ObjectFile<ELF32BE> *InputSectionBase::getFile<ELF32BE>() const; -template elf::ObjectFile<ELF64LE> *InputSectionBase::getFile<ELF64LE>() const; -template elf::ObjectFile<ELF64BE> *InputSectionBase::getFile<ELF64BE>() const; - -template MergeInputSection::MergeInputSection(elf::ObjectFile<ELF32LE> *, +template MergeInputSection::MergeInputSection(ObjFile<ELF32LE> *, const ELF32LE::Shdr *, StringRef); -template MergeInputSection::MergeInputSection(elf::ObjectFile<ELF32BE> *, +template MergeInputSection::MergeInputSection(ObjFile<ELF32BE> *, const ELF32BE::Shdr *, StringRef); -template MergeInputSection::MergeInputSection(elf::ObjectFile<ELF64LE> *, +template MergeInputSection::MergeInputSection(ObjFile<ELF64LE> *, const ELF64LE::Shdr *, StringRef); -template MergeInputSection::MergeInputSection(elf::ObjectFile<ELF64BE> *, +template MergeInputSection::MergeInputSection(ObjFile<ELF64BE> *, const ELF64BE::Shdr *, StringRef); -template EhInputSection::EhInputSection(elf::ObjectFile<ELF32LE> *, +template EhInputSection::EhInputSection(ObjFile<ELF32LE> *, const ELF32LE::Shdr *, StringRef); -template EhInputSection::EhInputSection(elf::ObjectFile<ELF32BE> *, +template EhInputSection::EhInputSection(ObjFile<ELF32BE> *, const ELF32BE::Shdr *, StringRef); -template EhInputSection::EhInputSection(elf::ObjectFile<ELF64LE> *, +template EhInputSection::EhInputSection(ObjFile<ELF64LE> *, const ELF64LE::Shdr *, StringRef); -template EhInputSection::EhInputSection(elf::ObjectFile<ELF64BE> *, +template EhInputSection::EhInputSection(ObjFile<ELF64BE> *, const ELF64BE::Shdr *, StringRef); template void EhInputSection::split<ELF32LE>(); |