1 //===- SymbolTable.cpp ----------------------------------------------------===//
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 #include "SymbolTable.h"
10 #include "InputFiles.h"
11 #include "Symbols.h"
12 #include "lld/Common/ErrorHandler.h"
13 #include "lld/Common/Memory.h"
14 
15 using namespace llvm;
16 using namespace lld;
17 using namespace lld::macho;
18 
19 Symbol *SymbolTable::find(StringRef name) {
20   auto it = symMap.find(llvm::CachedHashStringRef(name));
21   if (it == symMap.end())
22     return nullptr;
23   return symVector[it->second];
24 }
25 
26 std::pair<Symbol *, bool> SymbolTable::insert(StringRef name) {
27   auto p = symMap.insert({CachedHashStringRef(name), (int)symVector.size()});
28 
29   // Name already present in the symbol table.
30   if (!p.second)
31     return {symVector[p.first->second], false};
32 
33   // Name is a new symbol.
34   Symbol *sym = reinterpret_cast<Symbol *>(make<SymbolUnion>());
35   symVector.push_back(sym);
36   return {sym, true};
37 }
38 
39 Symbol *SymbolTable::addDefined(StringRef name, InputSection *isec,
40                                 uint32_t value) {
41   Symbol *s;
42   bool wasInserted;
43   std::tie(s, wasInserted) = insert(name);
44 
45   if (!wasInserted && isa<Defined>(s))
46     error("duplicate symbol: " + name);
47 
48   replaceSymbol<Defined>(s, name, isec, value);
49   return s;
50 }
51 
52 Symbol *SymbolTable::addUndefined(StringRef name) {
53   Symbol *s;
54   bool wasInserted;
55   std::tie(s, wasInserted) = insert(name);
56 
57   if (wasInserted)
58     replaceSymbol<Undefined>(s, name);
59   return s;
60 }
61 
62 Symbol *SymbolTable::addDylib(StringRef name, DylibFile *file) {
63   Symbol *s;
64   bool wasInserted;
65   std::tie(s, wasInserted) = insert(name);
66 
67   if (wasInserted || isa<Undefined>(s))
68     replaceSymbol<DylibSymbol>(s, file, name);
69   return s;
70 }
71 
72 SymbolTable *macho::symtab;
73