forked from OSchip/llvm-project
104 lines
3.2 KiB
C++
104 lines
3.2 KiB
C++
//===- SymbolTable.h --------------------------------------------*- C++ -*-===//
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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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#ifndef LLD_ELF_SYMBOL_TABLE_H
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#define LLD_ELF_SYMBOL_TABLE_H
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#include "InputFiles.h"
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#include "llvm/ADT/MapVector.h"
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namespace lld {
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namespace elf2 {
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struct Symbol;
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// SymbolTable is a bucket of all known symbols, including defined,
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// undefined, or lazy symbols (the last one is symbols in archive
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// files whose archive members are not yet loaded).
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//
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// We put all symbols of all files to a SymbolTable, and the
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// SymbolTable selects the "best" symbols if there are name
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// conflicts. For example, obviously, a defined symbol is better than
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// an undefined symbol. Or, if there's a conflict between a lazy and a
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// undefined, it'll read an archive member to read a real definition
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// to replace the lazy symbol. The logic is implemented in resolve().
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class SymbolTable {
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public:
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SymbolTable();
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void addFile(std::unique_ptr<InputFile> File);
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const ELFFileBase *getFirstELF() const {
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if (!ObjectFiles.empty())
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return ObjectFiles[0].get();
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if (!SharedFiles.empty())
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return SharedFiles[0].get();
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return nullptr;
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}
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bool shouldUseRela() const;
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const llvm::MapVector<StringRef, Symbol *> &getSymbols() const {
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return Symtab;
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}
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const std::vector<std::unique_ptr<ObjectFileBase>> &getObjectFiles() const {
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return ObjectFiles;
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}
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const std::vector<std::unique_ptr<SharedFileBase>> &getSharedFiles() const {
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return SharedFiles;
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}
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SymbolBody *getEntrySym() const {
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if (!EntrySym)
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return nullptr;
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return EntrySym->getReplacement();
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}
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template <class ELFT>
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void addSyntheticSym(StringRef Name, OutputSection<ELFT> &Section,
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typename llvm::object::ELFFile<ELFT>::uintX_t Value);
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private:
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Symbol *insert(SymbolBody *New);
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template <class ELFT> void addELFFile(ELFFileBase *File);
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void addELFFile(ELFFileBase *File);
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void addLazy(Lazy *New);
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void addMemberFile(Lazy *Body);
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template <class ELFT> void init(uint16_t EMachine);
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template <class ELFT> void resolve(SymbolBody *Body);
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template <class ELFT>
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void dupError(const SymbolBody &Old, const SymbolBody &New);
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std::vector<std::unique_ptr<ArchiveFile>> ArchiveFiles;
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// The order the global symbols are in is not defined. We can use an arbitrary
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// order, but it has to be reproducible. That is true even when cross linking.
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// The default hashing of StringRef produces different results on 32 and 64
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// bit systems so we use a MapVector. That is arbitrary, deterministic but
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// a bit inefficient.
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// FIXME: Experiment with passing in a custom hashing or sorting the symbols
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// once symbol resolution is finished.
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llvm::MapVector<StringRef, Symbol *> Symtab;
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llvm::BumpPtrAllocator Alloc;
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// The writer needs to infer the machine type from the object files.
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std::vector<std::unique_ptr<ObjectFileBase>> ObjectFiles;
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std::vector<std::unique_ptr<SharedFileBase>> SharedFiles;
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SymbolBody *EntrySym = nullptr;
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};
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} // namespace elf2
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} // namespace lld
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#endif
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