149 lines
6.1 KiB
C++
149 lines
6.1 KiB
C++
//===- SymbolTable.h --------------------------------------------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLD_WASM_SYMBOL_TABLE_H
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#define LLD_WASM_SYMBOL_TABLE_H
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#include "InputFiles.h"
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#include "LTO.h"
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#include "Symbols.h"
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#include "lld/Common/LLVM.h"
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#include "llvm/ADT/CachedHashString.h"
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#include "llvm/ADT/DenseSet.h"
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#include "llvm/BinaryFormat/WasmTraits.h"
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#include <optional>
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namespace lld::wasm {
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class InputSegment;
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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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ArrayRef<Symbol *> symbols() const { return symVector; }
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void wrap(Symbol *sym, Symbol *real, Symbol *wrap);
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void addFile(InputFile *file);
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void compileBitcodeFiles();
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Symbol *find(StringRef name);
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void replace(StringRef name, Symbol* sym);
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void trace(StringRef name);
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Symbol *addDefinedFunction(StringRef name, uint32_t flags, InputFile *file,
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InputFunction *function);
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Symbol *addDefinedData(StringRef name, uint32_t flags, InputFile *file,
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InputChunk *segment, uint64_t address, uint64_t size);
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Symbol *addDefinedGlobal(StringRef name, uint32_t flags, InputFile *file,
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InputGlobal *g);
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Symbol *addDefinedTag(StringRef name, uint32_t flags, InputFile *file,
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InputTag *t);
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Symbol *addDefinedTable(StringRef name, uint32_t flags, InputFile *file,
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InputTable *t);
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Symbol *addUndefinedFunction(StringRef name,
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std::optional<StringRef> importName,
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std::optional<StringRef> importModule,
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uint32_t flags, InputFile *file,
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const WasmSignature *signature,
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bool isCalledDirectly);
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Symbol *addUndefinedData(StringRef name, uint32_t flags, InputFile *file);
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Symbol *addUndefinedGlobal(StringRef name,
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std::optional<StringRef> importName,
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std::optional<StringRef> importModule,
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uint32_t flags, InputFile *file,
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const WasmGlobalType *type);
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Symbol *addUndefinedTable(StringRef name, std::optional<StringRef> importName,
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std::optional<StringRef> importModule,
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uint32_t flags, InputFile *file,
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const WasmTableType *type);
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Symbol *addUndefinedTag(StringRef name, std::optional<StringRef> importName,
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std::optional<StringRef> importModule, uint32_t flags,
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InputFile *file, const WasmSignature *sig);
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TableSymbol *resolveIndirectFunctionTable(bool required);
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void addLazy(ArchiveFile *f, const llvm::object::Archive::Symbol *sym);
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bool addComdat(StringRef name);
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DefinedData *addSyntheticDataSymbol(StringRef name, uint32_t flags);
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DefinedGlobal *addSyntheticGlobal(StringRef name, uint32_t flags,
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InputGlobal *global);
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DefinedFunction *addSyntheticFunction(StringRef name, uint32_t flags,
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InputFunction *function);
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DefinedData *addOptionalDataSymbol(StringRef name, uint64_t value = 0);
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DefinedGlobal *addOptionalGlobalSymbol(StringRef name, InputGlobal *global);
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DefinedTable *addSyntheticTable(StringRef name, uint32_t flags,
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InputTable *global);
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void handleSymbolVariants();
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void handleWeakUndefines();
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DefinedFunction *createUndefinedStub(const WasmSignature &sig);
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std::vector<ObjFile *> objectFiles;
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std::vector<SharedFile *> sharedFiles;
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std::vector<BitcodeFile *> bitcodeFiles;
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std::vector<InputFunction *> syntheticFunctions;
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std::vector<InputGlobal *> syntheticGlobals;
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std::vector<InputTable *> syntheticTables;
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private:
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std::pair<Symbol *, bool> insert(StringRef name, const InputFile *file);
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std::pair<Symbol *, bool> insertName(StringRef name);
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bool getFunctionVariant(Symbol* sym, const WasmSignature *sig,
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const InputFile *file, Symbol **out);
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InputFunction *replaceWithUnreachable(Symbol *sym, const WasmSignature &sig,
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StringRef debugName);
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void replaceWithUndefined(Symbol *sym);
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TableSymbol *createDefinedIndirectFunctionTable(StringRef name);
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TableSymbol *createUndefinedIndirectFunctionTable(StringRef name);
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// Maps symbol names to index into the symVector. -1 means that symbols
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// is to not yet in the vector but it should have tracing enabled if it is
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// ever added.
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llvm::DenseMap<llvm::CachedHashStringRef, int> symMap;
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std::vector<Symbol *> symVector;
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// For certain symbols types, e.g. function symbols, we allow for multiple
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// variants of the same symbol with different signatures.
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llvm::DenseMap<llvm::CachedHashStringRef, std::vector<Symbol *>> symVariants;
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llvm::DenseMap<WasmSignature, DefinedFunction *> stubFunctions;
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// Comdat groups define "link once" sections. If two comdat groups have the
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// same name, only one of them is linked, and the other is ignored. This set
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// is used to uniquify them.
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llvm::DenseSet<llvm::CachedHashStringRef> comdatGroups;
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// For LTO.
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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 lld::wasm
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#endif
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