Coverage Report

Created: 2018-01-17 17:22

/Users/buildslave/jenkins/workspace/clang-stage2-coverage-R/llvm/tools/lld/ELF/SymbolTable.h
Line
Count
Source
1
//===- SymbolTable.h --------------------------------------------*- C++ -*-===//
2
//
3
//                             The LLVM Linker
4
//
5
// This file is distributed under the University of Illinois Open Source
6
// License. See LICENSE.TXT for details.
7
//
8
//===----------------------------------------------------------------------===//
9
10
#ifndef LLD_ELF_SYMBOL_TABLE_H
11
#define LLD_ELF_SYMBOL_TABLE_H
12
13
#include "InputFiles.h"
14
#include "LTO.h"
15
#include "Strings.h"
16
#include "llvm/ADT/CachedHashString.h"
17
#include "llvm/ADT/DenseMap.h"
18
19
namespace lld {
20
namespace elf {
21
class Defined;
22
class SectionBase;
23
24
// SymbolTable is a bucket of all known symbols, including defined,
25
// undefined, or lazy symbols (the last one is symbols in archive
26
// files whose archive members are not yet loaded).
27
//
28
// We put all symbols of all files to a SymbolTable, and the
29
// SymbolTable selects the "best" symbols if there are name
30
// conflicts. For example, obviously, a defined symbol is better than
31
// an undefined symbol. Or, if there's a conflict between a lazy and a
32
// undefined, it'll read an archive member to read a real definition
33
// to replace the lazy symbol. The logic is implemented in the
34
// add*() functions, which are called by input files as they are parsed. There
35
// is one add* function per symbol type.
36
class SymbolTable {
37
public:
38
  template <class ELFT> void addFile(InputFile *File);
39
  template <class ELFT> void addCombinedLTOObject();
40
  template <class ELFT> void addSymbolWrap(StringRef Name);
41
  void applySymbolWrap();
42
43
3.77k
  ArrayRef<Symbol *> getSymbols() const { return SymVector; }
44
45
  Defined *addAbsolute(StringRef Name,
46
                       uint8_t Visibility = llvm::ELF::STV_HIDDEN,
47
                       uint8_t Binding = llvm::ELF::STB_GLOBAL);
48
49
  template <class ELFT> Symbol *addUndefined(StringRef Name);
50
  template <class ELFT>
51
  Symbol *addUndefined(StringRef Name, uint8_t Binding, uint8_t StOther,
52
                       uint8_t Type, bool CanOmitFromDynSym, InputFile *File);
53
  Symbol *addRegular(StringRef Name, uint8_t StOther, uint8_t Type,
54
                     uint64_t Value, uint64_t Size, uint8_t Binding,
55
                     SectionBase *Section, InputFile *File);
56
57
  template <class ELFT>
58
  void addShared(StringRef Name, SharedFile<ELFT> &F,
59
                 const typename ELFT::Sym &Sym, uint32_t Alignment,
60
                 uint32_t VerdefIndex);
61
62
  template <class ELFT>
63
  Symbol *addLazyArchive(StringRef Name, ArchiveFile &F,
64
                         const llvm::object::Archive::Symbol S);
65
66
  template <class ELFT> void addLazyObject(StringRef Name, LazyObjFile &Obj);
67
68
  Symbol *addBitcode(StringRef Name, uint8_t Binding, uint8_t StOther,
69
                     uint8_t Type, bool CanOmitFromDynSym, BitcodeFile &File);
70
71
  Symbol *addCommon(StringRef Name, uint64_t Size, uint32_t Alignment,
72
                    uint8_t Binding, uint8_t StOther, uint8_t Type,
73
                    InputFile &File);
74
75
  std::pair<Symbol *, bool> insert(StringRef Name);
76
  std::pair<Symbol *, bool> insert(StringRef Name, uint8_t Type,
77
                                   uint8_t Visibility, bool CanOmitFromDynSym,
78
                                   InputFile *File);
79
80
  template <class ELFT> void fetchIfLazy(StringRef Name);
81
  template <class ELFT> void scanShlibUndefined();
82
  void scanVersionScript();
83
84
  Symbol *find(StringRef Name);
85
86
  void trace(StringRef Name);
87
88
  void handleDynamicList();
89
90
private:
91
  std::vector<Symbol *> findByVersion(SymbolVersion Ver);
92
  std::vector<Symbol *> findAllByVersion(SymbolVersion Ver);
93
  void defsym(Symbol *Dst, Symbol *Src);
94
95
  llvm::StringMap<std::vector<Symbol *>> &getDemangledSyms();
96
  void handleAnonymousVersion();
97
  void assignExactVersion(SymbolVersion Ver, uint16_t VersionId,
98
                          StringRef VersionName);
99
  void assignWildcardVersion(SymbolVersion Ver, uint16_t VersionId);
100
101
  // The order the global symbols are in is not defined. We can use an arbitrary
102
  // order, but it has to be reproducible. That is true even when cross linking.
103
  // The default hashing of StringRef produces different results on 32 and 64
104
  // bit systems so we use a map to a vector. That is arbitrary, deterministic
105
  // but a bit inefficient.
106
  // FIXME: Experiment with passing in a custom hashing or sorting the symbols
107
  // once symbol resolution is finished.
108
  llvm::DenseMap<llvm::CachedHashStringRef, int> SymMap;
109
  std::vector<Symbol *> SymVector;
110
111
  // Comdat groups define "link once" sections. If two comdat groups have the
112
  // same name, only one of them is linked, and the other is ignored. This set
113
  // is used to uniquify them.
114
  llvm::DenseSet<llvm::CachedHashStringRef> ComdatGroups;
115
116
  // Set of .so files to not link the same shared object file more than once.
117
  llvm::DenseSet<StringRef> SoNames;
118
119
  // A map from demangled symbol names to their symbol objects.
120
  // This mapping is 1:N because two symbols with different versions
121
  // can have the same name. We use this map to handle "extern C++ {}"
122
  // directive in version scripts.
123
  llvm::Optional<llvm::StringMap<std::vector<Symbol *>>> DemangledSyms;
124
125
  struct WrappedSymbol {
126
    Symbol *Sym;
127
    Symbol *Real;
128
    Symbol *Wrap;
129
  };
130
131
  // For -wrap.
132
  std::vector<WrappedSymbol> WrappedSymbols;
133
134
  // For LTO.
135
  std::unique_ptr<BitcodeCompiler> LTO;
136
};
137
138
extern SymbolTable *Symtab;
139
} // namespace elf
140
} // namespace lld
141
142
#endif