Newer
Older
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
//===- Core/SymbolTable.cpp - Main Symbol Table ---------------------------===//
//
// The LLVM Linker
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "lld/Core/SymbolTable.h"
#include "lld/Core/Atom.h"
#include "lld/Core/File.h"
#include "lld/Core/InputFiles.h"
#include "lld/Core/Resolver.h"
#include "lld/Core/UndefinedAtom.h"
#include "lld/Platform/Platform.h"
#include "llvm/Support/ErrorHandling.h"
#include <algorithm>
#include <cassert>
#include <stdlib.h>
#include <vector>
namespace lld {
void SymbolTable::add(const Atom &atom) {
assert(atom.scope() != Atom::scopeTranslationUnit);
switch (atom.combine()) {
case Atom::combineNever:
case Atom::combineByName:
this->addByName(atom);
break;
case Atom::combineByTypeContent:
case Atom::combineByTypeContentDeep:
// TO DO: support constants merging
break;
}
}
enum NameCollisionResolution {
NCR_First,
NCR_Second,
NCR_Weak,
NCR_Larger,
NCR_Error
};
static NameCollisionResolution cases[5][5] = {
//regular tentative absolute undef sharedLib
{
// first is regular
NCR_Error, NCR_First, NCR_Error, NCR_First, NCR_First
},
{
// first is tentative
NCR_Second, NCR_Larger, NCR_Error, NCR_First, NCR_First
},
{
// first is absolute
NCR_Error, NCR_Error, NCR_Error, NCR_First, NCR_First
},
{
// first is undef
NCR_Second, NCR_Second, NCR_Second, NCR_First, NCR_Second
},
{
// first is sharedLib
NCR_Second, NCR_Second, NCR_Second, NCR_First, NCR_First
}
};
static NameCollisionResolution collide(Atom::Definition first,
Atom::Definition second) {
return cases[first][second];
}
void SymbolTable::addByName(const Atom &atom) {
llvm::StringRef name = atom.name();
const Atom *existing = this->findByName(name);
if (existing == NULL) {
// name is not in symbol table yet, add it associate with this atom
_nameTable[name] = &atom;
} else {
// name is already in symbol table and associated with another atom
switch (collide(existing->definition(), atom.definition())) {
case NCR_First:
// using first, just add new to _replacedAtoms
_replacedAtoms[&atom] = existing;
break;
case NCR_Second:
// using second, update tables
_nameTable[name] = &atom;
_replacedAtoms[existing] = &atom;
break;
default:
llvm::report_fatal_error("unhandled switch clause");
}
}
}
const Atom *SymbolTable::findByName(llvm::StringRef sym) {
NameToAtom::iterator pos = _nameTable.find(sym);
if (pos == _nameTable.end())
return NULL;
return pos->second;
}
bool SymbolTable::isDefined(llvm::StringRef sym) {
const Atom *atom = this->findByName(sym);
if (atom == NULL)
return false;
if (atom->definition() == Atom::definitionUndefined)
return false;
return true;
}
const Atom *SymbolTable::replacement(const Atom *atom) {
AtomToAtom::iterator pos = _replacedAtoms.find(atom);
if (pos == _replacedAtoms.end())
return atom;
// might be chain, recurse to end
return this->replacement(pos->second);
}
unsigned int SymbolTable::size() {
return _nameTable.size();
}
void SymbolTable::undefines(std::vector<const Atom *> &undefs) {
for (NameToAtom::iterator it = _nameTable.begin(),
end = _nameTable.end(); it != end; ++it) {
const Atom *atom = it->second;
assert(atom != NULL);
if (atom->definition() == Atom::definitionUndefined)
undefs.push_back(atom);
}
}
} // namespace lld