4340aad144
They are not fully functional yet, but this implements enough support for lld itself to read them. With that, delete the .so binary we were using for tests and start eating our own dog food. llvm-svn: 247487
144 lines
3.6 KiB
C++
144 lines
3.6 KiB
C++
//===- SymbolTable.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 "SymbolTable.h"
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#include "Config.h"
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#include "Error.h"
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#include "Symbols.h"
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using namespace llvm;
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using namespace llvm::object;
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using namespace lld;
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using namespace lld::elf2;
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SymbolTable::SymbolTable() {}
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void SymbolTable::addFile(std::unique_ptr<InputFile> File) {
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File->parse();
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InputFile *FileP = File.release();
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if (auto *AF = dyn_cast<ArchiveFile>(FileP)) {
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ArchiveFiles.emplace_back(AF);
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for (Lazy &Sym : AF->getLazySymbols())
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addLazy(&Sym);
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return;
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}
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addELFFile(cast<ELFFileBase>(FileP));
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}
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template <class ELFT> void SymbolTable::init() {
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if (Config->Shared)
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return;
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EntrySym = new (Alloc) Undefined<ELFT>("_start", Undefined<ELFT>::Synthetic);
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resolve<ELFT>(EntrySym);
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}
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template <class ELFT> void SymbolTable::addELFFile(ELFFileBase *File) {
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if (const ELFFileBase *Old = getFirstELF()) {
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if (!Old->isCompatibleWith(*File))
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error(Twine(Old->getName() + " is incompatible with " + File->getName()));
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} else {
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init<ELFT>();
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}
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if (auto *O = dyn_cast<ObjectFileBase>(File)) {
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ObjectFiles.emplace_back(O);
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for (SymbolBody *Body : O->getSymbols())
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resolve<ELFT>(Body);
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}
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if (auto *S = dyn_cast<SharedFile<ELFT>>(File)) {
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SharedFiles.emplace_back(S);
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for (SharedSymbol<ELFT> &Body : S->getSharedSymbols())
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resolve<ELFT>(&Body);
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}
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}
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void SymbolTable::addELFFile(ELFFileBase *File) {
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switch (File->getELFKind()) {
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case ELF32LEKind:
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addELFFile<ELF32LE>(File);
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break;
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case ELF32BEKind:
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addELFFile<ELF32BE>(File);
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break;
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case ELF64LEKind:
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addELFFile<ELF64LE>(File);
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break;
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case ELF64BEKind:
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addELFFile<ELF64BE>(File);
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break;
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}
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}
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// This function resolves conflicts if there's an existing symbol with
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// the same name. Decisions are made based on symbol type.
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template <class ELFT> void SymbolTable::resolve(SymbolBody *New) {
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Symbol *Sym = insert(New);
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if (Sym->Body == New)
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return;
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SymbolBody *Existing = Sym->Body;
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if (Lazy *L = dyn_cast<Lazy>(Existing)) {
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if (New->isUndefined()) {
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addMemberFile(L);
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return;
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}
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// Found a definition for something also in an archive. Ignore the archive
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// definition.
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Sym->Body = New;
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return;
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}
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// compare() returns -1, 0, or 1 if the lhs symbol is less preferable,
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// equivalent (conflicting), or more preferable, respectively.
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int comp = Existing->compare<ELFT>(New);
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if (comp < 0)
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Sym->Body = New;
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if (comp == 0)
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error(Twine("duplicate symbol: ") + Sym->Body->getName());
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}
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Symbol *SymbolTable::insert(SymbolBody *New) {
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// Find an existing Symbol or create and insert a new one.
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StringRef Name = New->getName();
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Symbol *&Sym = Symtab[Name];
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if (!Sym) {
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Sym = new (Alloc) Symbol(New);
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New->setBackref(Sym);
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return Sym;
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}
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New->setBackref(Sym);
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return Sym;
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}
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void SymbolTable::addLazy(Lazy *New) {
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Symbol *Sym = insert(New);
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if (Sym->Body == New)
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return;
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SymbolBody *Existing = Sym->Body;
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if (Existing->isDefined() || Existing->isLazy())
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return;
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Sym->Body = New;
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assert(Existing->isUndefined() && "Unexpected symbol kind.");
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addMemberFile(New);
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}
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void SymbolTable::addMemberFile(Lazy *Body) {
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std::unique_ptr<InputFile> File = Body->getMember();
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// getMember returns nullptr if the member was already read from the library.
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if (!File)
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return;
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addFile(std::move(File));
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}
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