forked from OSchip/llvm-project
70 lines
2.0 KiB
C++
70 lines
2.0 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 "Error.h"
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#include "Symbols.h"
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using namespace llvm;
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using namespace lld;
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using namespace lld::elf2;
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SymbolTable::SymbolTable() { resolve(new (Alloc) Undefined("_start")); }
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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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auto *P = cast<ObjectFileBase>(FileP);
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addObject(P);
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}
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void SymbolTable::addObject(ObjectFileBase *File) {
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if (!ObjectFiles.empty()) {
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ObjectFileBase &Old = *ObjectFiles[0];
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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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}
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ObjectFiles.emplace_back(File);
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for (SymbolBody *Body : File->getSymbols())
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resolve(Body);
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}
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void SymbolTable::reportRemainingUndefines() {
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for (auto &I : Symtab) {
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Symbol *Sym = I.second;
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if (auto *Undef = dyn_cast<Undefined>(Sym->Body))
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error(Twine("undefined symbol: ") + Undef->getName());
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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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void SymbolTable::resolve(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;
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}
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New->setBackref(Sym);
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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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SymbolBody *Existing = Sym->Body;
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int comp = Existing->compare(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: ") + Name);
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}
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