1//===- SymbolTable.h --------------------------------------------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#ifndef LLD_COFF_SYMBOL_TABLE_H
10#define LLD_COFF_SYMBOL_TABLE_H
11
12#include "InputFiles.h"
13#include "LTO.h"
14#include "llvm/ADT/CachedHashString.h"
15#include "llvm/ADT/DenseMap.h"
16#include "llvm/ADT/DenseMapInfo.h"
17#include "llvm/Support/raw_ostream.h"
18
19namespace llvm {
20struct LTOCodeGenerator;
21}
22
23namespace lld {
24namespace coff {
25
26class Chunk;
27class CommonChunk;
28class Defined;
29class DefinedAbsolute;
30class DefinedRegular;
31class DefinedRelative;
32class LazyArchive;
33class SectionChunk;
34class Symbol;
35
36// SymbolTable is a bucket of all known symbols, including defined,
37// undefined, or lazy symbols (the last one is symbols in archive
38// files whose archive members are not yet loaded).
39//
40// We put all symbols of all files to a SymbolTable, and the
41// SymbolTable selects the "best" symbols if there are name
42// conflicts. For example, obviously, a defined symbol is better than
43// an undefined symbol. Or, if there's a conflict between a lazy and a
44// undefined, it'll read an archive member to read a real definition
45// to replace the lazy symbol. The logic is implemented in the
46// add*() functions, which are called by input files as they are parsed.
47// There is one add* function per symbol type.
48class SymbolTable {
49public:
50 void addFile(InputFile *file);
51
52 // Emit errors for symbols that cannot be resolved.
53 void reportUnresolvable();
54
55 // Try to resolve any undefined symbols and update the symbol table
56 // accordingly, then print an error message for any remaining undefined
57 // symbols and warn about imported local symbols.
58 void resolveRemainingUndefines();
59
60 void loadMinGWAutomaticImports();
61 bool handleMinGWAutomaticImport(Symbol *sym, StringRef name);
62
63 // Returns a list of chunks of selected symbols.
64 std::vector<Chunk *> getChunks();
65
66 // Returns a symbol for a given name. Returns a nullptr if not found.
67 Symbol *find(StringRef name);
68 Symbol *findUnderscore(StringRef name);
69
70 // Occasionally we have to resolve an undefined symbol to its
71 // mangled symbol. This function tries to find a mangled name
72 // for U from the symbol table, and if found, set the symbol as
73 // a weak alias for U.
74 Symbol *findMangle(StringRef name);
75
76 // Build a set of COFF objects representing the combined contents of
77 // BitcodeFiles and add them to the symbol table. Called after all files are
78 // added and before the writer writes results to a file.
79 void addCombinedLTOObjects();
80
81 // Creates an Undefined symbol for a given name.
82 Symbol *addUndefined(StringRef name);
83
84 Symbol *addSynthetic(StringRef n, Chunk *c);
85 Symbol *addAbsolute(StringRef n, uint64_t va);
86
87 Symbol *addUndefined(StringRef name, InputFile *f, bool isWeakAlias);
88 void addLazyArchive(ArchiveFile *f, const Archive::Symbol &sym);
89 void addLazyObject(LazyObjFile *f, StringRef n);
90 Symbol *addAbsolute(StringRef n, COFFSymbolRef s);
91 Symbol *addRegular(InputFile *f, StringRef n,
92 const llvm::object::coff_symbol_generic *s = nullptr,
93 SectionChunk *c = nullptr, uint32_t sectionOffset = 0);
94 std::pair<DefinedRegular *, bool>
95 addComdat(InputFile *f, StringRef n,
96 const llvm::object::coff_symbol_generic *s = nullptr);
97 Symbol *addCommon(InputFile *f, StringRef n, uint64_t size,
98 const llvm::object::coff_symbol_generic *s = nullptr,
99 CommonChunk *c = nullptr);
100 Symbol *addImportData(StringRef n, ImportFile *f);
101 Symbol *addImportThunk(StringRef name, DefinedImportData *s,
102 uint16_t machine);
103 void addLibcall(StringRef name);
104
105 void reportDuplicate(Symbol *existing, InputFile *newFile,
106 SectionChunk *newSc = nullptr,
107 uint32_t newSectionOffset = 0);
108
109 // A list of chunks which to be added to .rdata.
110 std::vector<Chunk *> localImportChunks;
111
112 // Iterates symbols in non-determinstic hash table order.
113 template <typename T> void forEachSymbol(T callback) {
114 for (auto &pair : symMap)
115 callback(pair.second);
116 }
117
118private:
119 /// Given a name without "__imp_" prefix, returns a defined symbol
120 /// with the "__imp_" prefix, if it exists.
121 Defined *impSymbol(StringRef name);
122 /// Inserts symbol if not already present.
123 std::pair<Symbol *, bool> insert(StringRef name);
124 /// Same as insert(Name), but also sets isUsedInRegularObj.
125 std::pair<Symbol *, bool> insert(StringRef name, InputFile *f);
126
127 std::vector<Symbol *> getSymsWithPrefix(StringRef prefix);
128
129 llvm::DenseMap<llvm::CachedHashStringRef, Symbol *> symMap;
130 std::unique_ptr<BitcodeCompiler> lto;
131};
132
133extern SymbolTable *symtab;
134
135std::vector<std::string> getSymbolLocations(ObjFile *file, uint32_t symIndex);
136
137} // namespace coff
138} // namespace lld
139
140#endif
141