forked from OSchip/llvm-project
373 lines
12 KiB
C++
373 lines
12 KiB
C++
//===- InputFiles.cpp -----------------------------------------------------===//
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//
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// The LLVM Linker
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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#include "InputFiles.h"
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#include "InputSection.h"
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#include "Error.h"
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#include "Symbols.h"
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#include "llvm/ADT/STLExtras.h"
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using namespace llvm;
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using namespace llvm::ELF;
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using namespace llvm::object;
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using namespace llvm::sys::fs;
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using namespace lld;
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using namespace lld::elf2;
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namespace {
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class ECRAII {
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std::error_code EC;
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public:
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std::error_code &getEC() { return EC; }
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~ECRAII() { error(EC); }
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};
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}
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template <class ELFT>
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ELFFileBase<ELFT>::ELFFileBase(Kind K, ELFKind EKind, MemoryBufferRef M)
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: InputFile(K, M), EKind(EKind), ELFObj(MB.getBuffer(), ECRAII().getEC()) {}
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template <class ELFT>
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typename ELFFileBase<ELFT>::Elf_Sym_Range
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ELFFileBase<ELFT>::getSymbolsHelper(bool Local) {
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if (!Symtab)
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return Elf_Sym_Range(nullptr, nullptr);
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Elf_Sym_Range Syms = ELFObj.symbols(Symtab);
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uint32_t NumSymbols = std::distance(Syms.begin(), Syms.end());
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uint32_t FirstNonLocal = Symtab->sh_info;
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if (FirstNonLocal > NumSymbols)
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error("Invalid sh_info in symbol table");
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if (!Local)
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return make_range(Syms.begin() + FirstNonLocal, Syms.end());
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// +1 to skip over dummy symbol.
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return make_range(Syms.begin() + 1, Syms.begin() + FirstNonLocal);
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}
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template <class ELFT> void ELFFileBase<ELFT>::initStringTable() {
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if (!Symtab)
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return;
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ErrorOr<StringRef> StringTableOrErr = ELFObj.getStringTableForSymtab(*Symtab);
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error(StringTableOrErr.getError());
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StringTable = *StringTableOrErr;
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}
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template <class ELFT>
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typename ELFFileBase<ELFT>::Elf_Sym_Range
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ELFFileBase<ELFT>::getNonLocalSymbols() {
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return getSymbolsHelper(false);
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}
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template <class ELFT>
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ObjectFile<ELFT>::ObjectFile(MemoryBufferRef M)
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: ELFFileBase<ELFT>(Base::ObjectKind, Base::getStaticELFKind(), M) {}
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template <class ELFT>
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typename ObjectFile<ELFT>::Elf_Sym_Range ObjectFile<ELFT>::getLocalSymbols() {
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return this->getSymbolsHelper(true);
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}
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template <class ELFT>
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void elf2::ObjectFile<ELFT>::parse(DenseSet<StringRef> &Comdats) {
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// Read section and symbol tables.
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initializeSections(Comdats);
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initializeSymbols();
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}
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template <class ELFT>
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StringRef ObjectFile<ELFT>::getShtGroupSignature(const Elf_Shdr &Sec) {
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const ELFFile<ELFT> &Obj = this->ELFObj;
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uint32_t SymtabdSectionIndex = Sec.sh_link;
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ErrorOr<const Elf_Shdr *> SecOrErr = Obj.getSection(SymtabdSectionIndex);
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error(SecOrErr);
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const Elf_Shdr *SymtabSec = *SecOrErr;
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uint32_t SymIndex = Sec.sh_info;
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const Elf_Sym *Sym = Obj.getSymbol(SymtabSec, SymIndex);
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ErrorOr<StringRef> StringTableOrErr = Obj.getStringTableForSymtab(*SymtabSec);
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error(StringTableOrErr);
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ErrorOr<StringRef> SignatureOrErr = Sym->getName(*StringTableOrErr);
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error(SignatureOrErr);
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return *SignatureOrErr;
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}
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template <class ELFT>
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ArrayRef<typename ObjectFile<ELFT>::GroupEntryType>
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ObjectFile<ELFT>::getShtGroupEntries(const Elf_Shdr &Sec) {
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const ELFFile<ELFT> &Obj = this->ELFObj;
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ErrorOr<ArrayRef<GroupEntryType>> EntriesOrErr =
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Obj.template getSectionContentsAsArray<GroupEntryType>(&Sec);
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error(EntriesOrErr.getError());
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ArrayRef<GroupEntryType> Entries = *EntriesOrErr;
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if (Entries.empty() || Entries[0] != GRP_COMDAT)
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error("Unsupported SHT_GROUP format");
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return Entries.slice(1);
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}
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template <class ELFT>
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void elf2::ObjectFile<ELFT>::initializeSections(DenseSet<StringRef> &Comdats) {
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uint64_t Size = this->ELFObj.getNumSections();
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Sections.resize(Size);
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unsigned I = -1;
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const ELFFile<ELFT> &Obj = this->ELFObj;
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for (const Elf_Shdr &Sec : Obj.sections()) {
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++I;
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if (Sections[I] == &InputSection<ELFT>::Discarded)
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continue;
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switch (Sec.sh_type) {
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case SHT_GROUP:
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Sections[I] = &InputSection<ELFT>::Discarded;
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if (Comdats.insert(getShtGroupSignature(Sec)).second)
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continue;
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for (GroupEntryType E : getShtGroupEntries(Sec)) {
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uint32_t SecIndex = E;
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if (SecIndex >= Size)
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error("Invalid section index in group");
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Sections[SecIndex] = &InputSection<ELFT>::Discarded;
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}
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break;
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case SHT_SYMTAB:
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this->Symtab = &Sec;
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break;
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case SHT_SYMTAB_SHNDX: {
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ErrorOr<ArrayRef<Elf_Word>> ErrorOrTable = Obj.getSHNDXTable(Sec);
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error(ErrorOrTable);
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SymtabSHNDX = *ErrorOrTable;
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break;
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}
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case SHT_STRTAB:
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case SHT_NULL:
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break;
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case SHT_RELA:
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case SHT_REL: {
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uint32_t RelocatedSectionIndex = Sec.sh_info;
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if (RelocatedSectionIndex >= Size)
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error("Invalid relocated section index");
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InputSection<ELFT> *RelocatedSection = Sections[RelocatedSectionIndex];
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if (!RelocatedSection)
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error("Unsupported relocation reference");
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RelocatedSection->RelocSections.push_back(&Sec);
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break;
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}
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default:
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Sections[I] = new (this->Alloc) InputSection<ELFT>(this, &Sec);
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break;
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}
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}
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}
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template <class ELFT> void elf2::ObjectFile<ELFT>::initializeSymbols() {
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this->initStringTable();
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Elf_Sym_Range Syms = this->getNonLocalSymbols();
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uint32_t NumSymbols = std::distance(Syms.begin(), Syms.end());
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this->SymbolBodies.reserve(NumSymbols);
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for (const Elf_Sym &Sym : Syms)
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this->SymbolBodies.push_back(createSymbolBody(this->StringTable, &Sym));
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}
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template <class ELFT>
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SymbolBody *elf2::ObjectFile<ELFT>::createSymbolBody(StringRef StringTable,
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const Elf_Sym *Sym) {
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ErrorOr<StringRef> NameOrErr = Sym->getName(StringTable);
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error(NameOrErr.getError());
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StringRef Name = *NameOrErr;
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uint32_t SecIndex = Sym->st_shndx;
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switch (SecIndex) {
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case SHN_ABS:
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return new (this->Alloc) DefinedAbsolute<ELFT>(Name, *Sym);
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case SHN_UNDEF:
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return new (this->Alloc) Undefined<ELFT>(Name, *Sym);
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case SHN_COMMON:
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return new (this->Alloc) DefinedCommon<ELFT>(Name, *Sym);
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case SHN_XINDEX:
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SecIndex = this->ELFObj.getExtendedSymbolTableIndex(Sym, this->Symtab,
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SymtabSHNDX);
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break;
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}
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if (SecIndex >= Sections.size() || !SecIndex || !Sections[SecIndex])
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error("Invalid section index");
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switch (Sym->getBinding()) {
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default:
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error("unexpected binding");
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case STB_GLOBAL:
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case STB_WEAK:
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case STB_GNU_UNIQUE: {
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InputSection<ELFT> *Sec = Sections[SecIndex];
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if (Sec == &InputSection<ELFT>::Discarded)
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return new (this->Alloc) Undefined<ELFT>(Name, *Sym);
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return new (this->Alloc) DefinedRegular<ELFT>(Name, *Sym, *Sec);
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}
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}
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}
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static std::unique_ptr<Archive> openArchive(MemoryBufferRef MB) {
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ErrorOr<std::unique_ptr<Archive>> ArchiveOrErr = Archive::create(MB);
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error(ArchiveOrErr, "Failed to parse archive");
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return std::move(*ArchiveOrErr);
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}
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void ArchiveFile::parse() {
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File = openArchive(MB);
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// Allocate a buffer for Lazy objects.
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size_t NumSyms = File->getNumberOfSymbols();
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LazySymbols.reserve(NumSyms);
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// Read the symbol table to construct Lazy objects.
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for (const Archive::Symbol &Sym : File->symbols())
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LazySymbols.emplace_back(this, Sym);
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}
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// Returns a buffer pointing to a member file containing a given symbol.
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MemoryBufferRef ArchiveFile::getMember(const Archive::Symbol *Sym) {
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ErrorOr<Archive::child_iterator> ItOrErr = Sym->getMember();
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error(ItOrErr, "Could not get the member for symbol " + Sym->getName());
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Archive::child_iterator It = *ItOrErr;
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if (!Seen.insert(It->getChildOffset()).second)
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return MemoryBufferRef();
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ErrorOr<MemoryBufferRef> Ret = It->getMemoryBufferRef();
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error(Ret, "Could not get the buffer for the member defining symbol " +
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Sym->getName());
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return *Ret;
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}
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std::vector<MemoryBufferRef> ArchiveFile::getMembers() {
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File = openArchive(MB);
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std::vector<MemoryBufferRef> Result;
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for (const Archive::Child &Child : File->children()) {
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ErrorOr<MemoryBufferRef> MbOrErr = Child.getMemoryBufferRef();
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error(MbOrErr, "Could not get the buffer for a child of the archive " +
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File->getFileName());
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Result.push_back(MbOrErr.get());
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}
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return Result;
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}
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template <class ELFT>
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SharedFile<ELFT>::SharedFile(MemoryBufferRef M)
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: ELFFileBase<ELFT>(Base::SharedKind, Base::getStaticELFKind(), M) {
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AsNeeded = Config->AsNeeded;
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}
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template <class ELFT> void SharedFile<ELFT>::parseSoName() {
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typedef typename ELFFile<ELFT>::Elf_Dyn Elf_Dyn;
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typedef typename ELFFile<ELFT>::uintX_t uintX_t;
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const Elf_Shdr *DynamicSec = nullptr;
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const ELFFile<ELFT> Obj = this->ELFObj;
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for (const Elf_Shdr &Sec : Obj.sections()) {
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uint32_t Type = Sec.sh_type;
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if (Type == SHT_DYNSYM)
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this->Symtab = &Sec;
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else if (Type == SHT_DYNAMIC)
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DynamicSec = &Sec;
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}
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this->initStringTable();
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this->SoName = this->getName();
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if (!DynamicSec)
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return;
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auto *Begin =
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reinterpret_cast<const Elf_Dyn *>(Obj.base() + DynamicSec->sh_offset);
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const Elf_Dyn *End = Begin + DynamicSec->sh_size / sizeof(Elf_Dyn);
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for (const Elf_Dyn &Dyn : make_range(Begin, End)) {
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if (Dyn.d_tag == DT_SONAME) {
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uintX_t Val = Dyn.getVal();
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if (Val >= this->StringTable.size())
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error("Invalid DT_SONAME entry");
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this->SoName = StringRef(this->StringTable.data() + Val);
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return;
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}
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}
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}
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template <class ELFT> void SharedFile<ELFT>::parse() {
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Elf_Sym_Range Syms = this->getNonLocalSymbols();
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uint32_t NumSymbols = std::distance(Syms.begin(), Syms.end());
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SymbolBodies.reserve(NumSymbols);
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for (const Elf_Sym &Sym : Syms) {
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if (Sym.isUndefined())
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continue;
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ErrorOr<StringRef> NameOrErr = Sym.getName(this->StringTable);
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error(NameOrErr.getError());
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StringRef Name = *NameOrErr;
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SymbolBodies.emplace_back(this, Name, Sym);
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}
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}
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template <typename T>
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static std::unique_ptr<InputFile> createELFFileAux(MemoryBufferRef MB) {
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std::unique_ptr<T> Ret = llvm::make_unique<T>(MB);
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if (!Config->FirstElf)
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Config->FirstElf = Ret.get();
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if (Config->ElfKind == ELFNoneKind) {
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Config->ElfKind = Ret->getELFKind();
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Config->EMachine = Ret->getEMachine();
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}
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return std::move(Ret);
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}
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template <template <class> class T>
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std::unique_ptr<InputFile> lld::elf2::createELFFile(MemoryBufferRef MB) {
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using namespace llvm;
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std::pair<unsigned char, unsigned char> Type =
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object::getElfArchType(MB.getBuffer());
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if (Type.second != ELF::ELFDATA2LSB && Type.second != ELF::ELFDATA2MSB)
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error("Invalid data encoding: " + MB.getBufferIdentifier());
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if (Type.first == ELF::ELFCLASS32) {
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if (Type.second == ELF::ELFDATA2LSB)
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return createELFFileAux<T<object::ELF32LE>>(MB);
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return createELFFileAux<T<object::ELF32BE>>(MB);
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}
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if (Type.first == ELF::ELFCLASS64) {
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if (Type.second == ELF::ELFDATA2LSB)
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return createELFFileAux<T<object::ELF64LE>>(MB);
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return createELFFileAux<T<object::ELF64BE>>(MB);
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}
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error("Invalid file class: " + MB.getBufferIdentifier());
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}
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namespace lld {
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namespace elf2 {
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template class ELFFileBase<llvm::object::ELF32LE>;
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template class ELFFileBase<llvm::object::ELF32BE>;
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template class ELFFileBase<llvm::object::ELF64LE>;
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template class ELFFileBase<llvm::object::ELF64BE>;
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template class ObjectFile<llvm::object::ELF32LE>;
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template class ObjectFile<llvm::object::ELF32BE>;
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template class ObjectFile<llvm::object::ELF64LE>;
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template class ObjectFile<llvm::object::ELF64BE>;
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template class SharedFile<llvm::object::ELF32LE>;
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template class SharedFile<llvm::object::ELF32BE>;
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template class SharedFile<llvm::object::ELF64LE>;
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template class SharedFile<llvm::object::ELF64BE>;
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template std::unique_ptr<InputFile> createELFFile<ObjectFile>(MemoryBufferRef);
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template std::unique_ptr<InputFile> createELFFile<SharedFile>(MemoryBufferRef);
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}
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}
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