2ba4d231d1
Summary: r338767 updated the COFF and wasm linker SymbolTable code to be strutured more like the ELF linker's. That inadvertedly changed the behavior of the COFF linker so that lazy symbols would be marked as used in regular objects. This change adds an overload of the insert() function, similar to the ELF linker, which does not perform that marking. Reviewers: ruiu, rnk, hans Subscribers: aheejin, sunfish, llvm-commits Differential Revision: https://reviews.llvm.org/D51720 llvm-svn: 341585
130 lines
4.4 KiB
C++
130 lines
4.4 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_COFF_SYMBOL_TABLE_H
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#define LLD_COFF_SYMBOL_TABLE_H
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#include "InputFiles.h"
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#include "LTO.h"
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#include "llvm/ADT/CachedHashString.h"
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#include "llvm/ADT/DenseMap.h"
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#include "llvm/ADT/DenseMapInfo.h"
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#include "llvm/Support/raw_ostream.h"
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namespace llvm {
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struct LTOCodeGenerator;
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}
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namespace lld {
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namespace coff {
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class Chunk;
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class CommonChunk;
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class Defined;
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class DefinedAbsolute;
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class DefinedRelative;
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class Lazy;
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class SectionChunk;
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class 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 the
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// add*() functions, which are called by input files as they are parsed.
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// There is one add* function per symbol type.
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class SymbolTable {
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public:
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void addFile(InputFile *File);
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// Try to resolve any undefined symbols and update the symbol table
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// accordingly, then print an error message for any remaining undefined
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// symbols.
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void reportRemainingUndefines();
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void loadMinGWAutomaticImports();
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bool handleMinGWAutomaticImport(Symbol *Sym, StringRef Name);
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// Returns a list of chunks of selected symbols.
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std::vector<Chunk *> getChunks();
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// Returns a symbol for a given name. Returns a nullptr if not found.
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Symbol *find(StringRef Name);
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Symbol *findUnderscore(StringRef Name);
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// Occasionally we have to resolve an undefined symbol to its
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// mangled symbol. This function tries to find a mangled name
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// for U from the symbol table, and if found, set the symbol as
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// a weak alias for U.
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void mangleMaybe(Symbol *B);
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StringRef findMangle(StringRef Name);
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// Build a set of COFF objects representing the combined contents of
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// BitcodeFiles and add them to the symbol table. Called after all files are
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// added and before the writer writes results to a file.
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void addCombinedLTOObjects();
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std::vector<StringRef> compileBitcodeFiles();
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// Creates an Undefined symbol for a given name.
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Symbol *addUndefined(StringRef Name);
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Symbol *addSynthetic(StringRef N, Chunk *C);
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Symbol *addAbsolute(StringRef N, uint64_t VA);
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Symbol *addUndefined(StringRef Name, InputFile *F, bool IsWeakAlias);
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void addLazy(ArchiveFile *F, const Archive::Symbol Sym);
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Symbol *addAbsolute(StringRef N, COFFSymbolRef S);
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Symbol *addRegular(InputFile *F, StringRef N,
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const llvm::object::coff_symbol_generic *S = nullptr,
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SectionChunk *C = nullptr);
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std::pair<Symbol *, bool>
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addComdat(InputFile *F, StringRef N,
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const llvm::object::coff_symbol_generic *S = nullptr);
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Symbol *addCommon(InputFile *F, StringRef N, uint64_t Size,
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const llvm::object::coff_symbol_generic *S = nullptr,
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CommonChunk *C = nullptr);
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Symbol *addImportData(StringRef N, ImportFile *F);
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Symbol *addImportThunk(StringRef Name, DefinedImportData *S,
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uint16_t Machine);
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void reportDuplicate(Symbol *Existing, InputFile *NewFile);
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// A list of chunks which to be added to .rdata.
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std::vector<Chunk *> LocalImportChunks;
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// Iterates symbols in non-determinstic hash table order.
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template <typename T> void forEachSymbol(T Callback) {
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for (auto &Pair : SymMap)
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Callback(Pair.second);
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}
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private:
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/// Inserts symbol if not already present.
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std::pair<Symbol *, bool> insert(StringRef Name);
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/// Same as insert(Name), but also sets IsUsedInRegularObj.
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std::pair<Symbol *, bool> insert(StringRef Name, InputFile *F);
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StringRef findByPrefix(StringRef Prefix);
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llvm::DenseMap<llvm::CachedHashStringRef, Symbol *> SymMap;
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std::unique_ptr<BitcodeCompiler> LTO;
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};
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extern SymbolTable *Symtab;
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} // namespace coff
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} // namespace lld
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#endif
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