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
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
|
//===- lib/ReaderWriter/ELF/Mips/MipsTargetHandler.h ----------------------===//
//
// The LLVM Linker
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#ifndef LLD_READER_WRITER_ELF_MIPS_MIPS_TARGET_HANDLER_H
#define LLD_READER_WRITER_ELF_MIPS_MIPS_TARGET_HANDLER_H
#include "DefaultTargetHandler.h"
#include "MipsELFReader.h"
#include "MipsLinkingContext.h"
#include "MipsRelocationHandler.h"
#include "MipsSectionChunks.h"
#include "TargetLayout.h"
namespace lld {
namespace elf {
/// \brief TargetLayout for Mips
template <class ELFType>
class MipsTargetLayout final : public TargetLayout<ELFType> {
public:
MipsTargetLayout(const MipsLinkingContext &ctx)
: TargetLayout<ELFType>(ctx),
_gotSection(new (_alloc) MipsGOTSection<ELFType>(ctx)),
_pltSection(new (_alloc) MipsPLTSection<ELFType>(ctx)) {}
const MipsGOTSection<ELFType> &getGOTSection() const { return *_gotSection; }
const MipsPLTSection<ELFType> &getPLTSection() const { return *_pltSection; }
AtomSection<ELFType> *
createSection(StringRef name, int32_t type,
DefinedAtom::ContentPermissions permissions,
Layout::SectionOrder order) override {
if (type == DefinedAtom::typeGOT && name == ".got")
return _gotSection;
if (type == DefinedAtom::typeStub && name == ".plt")
return _pltSection;
return DefaultLayout<ELFType>::createSection(name, type, permissions,
order);
}
StringRef getSectionName(const DefinedAtom *da) const override {
return llvm::StringSwitch<StringRef>(da->customSectionName())
.StartsWith(".ctors", ".ctors")
.StartsWith(".dtors", ".dtors")
.Default(TargetLayout<ELFType>::getSectionName(da));
}
Layout::SegmentType getSegmentType(Section<ELFType> *section) const override {
switch (section->order()) {
case DefaultLayout<ELFType>::ORDER_CTORS:
case DefaultLayout<ELFType>::ORDER_DTORS:
return llvm::ELF::PT_LOAD;
default:
return TargetLayout<ELFType>::getSegmentType(section);
}
}
/// \brief GP offset relative to .got section.
uint64_t getGPOffset() const { return 0x7FF0; }
/// \brief Get '_gp' symbol atom layout.
AtomLayout *getGP() {
if (!_gpAtom.hasValue()) {
auto atom = this->findAbsoluteAtom("_gp");
_gpAtom = atom != this->absoluteAtoms().end() ? *atom : nullptr;
}
return *_gpAtom;
}
/// \brief Get '_gp_disp' symbol atom layout.
AtomLayout *getGPDisp() {
if (!_gpDispAtom.hasValue()) {
auto atom = this->findAbsoluteAtom("_gp_disp");
_gpDispAtom = atom != this->absoluteAtoms().end() ? *atom : nullptr;
}
return *_gpDispAtom;
}
private:
llvm::BumpPtrAllocator _alloc;
MipsGOTSection<ELFType> *_gotSection;
MipsPLTSection<ELFType> *_pltSection;
llvm::Optional<AtomLayout *> _gpAtom;
llvm::Optional<AtomLayout *> _gpDispAtom;
};
/// \brief Mips Runtime file.
template <class ELFType>
class MipsRuntimeFile final : public CRuntimeFile<ELFType> {
public:
MipsRuntimeFile(const MipsLinkingContext &context)
: CRuntimeFile<ELFType>(context, "Mips runtime file") {}
};
/// \brief TargetHandler for Mips
class MipsTargetHandler final : public DefaultTargetHandler<Mips32ElELFType> {
public:
MipsTargetHandler(MipsLinkingContext &context);
MipsTargetLayout<Mips32ElELFType> &getTargetLayout() override {
return *_targetLayout;
}
std::unique_ptr<Reader> getObjReader(bool atomizeStrings) override {
return std::unique_ptr<Reader>(new MipsELFObjectReader(atomizeStrings));
}
const MipsTargetRelocationHandler &getRelocationHandler() const override {
return *_relocationHandler;
}
std::unique_ptr<Writer> getWriter() override;
void registerRelocationNames(Registry ®istry) override;
private:
static const Registry::KindStrings kindStrings[];
MipsLinkingContext &_context;
std::unique_ptr<MipsRuntimeFile<Mips32ElELFType>> _runtimeFile;
std::unique_ptr<MipsTargetLayout<Mips32ElELFType>> _targetLayout;
std::unique_ptr<MipsTargetRelocationHandler> _relocationHandler;
};
template <class ELFT>
class MipsDynamicSymbolTable : public DynamicSymbolTable<ELFT> {
public:
MipsDynamicSymbolTable(const MipsLinkingContext &context,
MipsTargetLayout<ELFT> &layout)
: DynamicSymbolTable<ELFT>(
context, layout, ".dynsym",
DefaultLayout<ELFT>::ORDER_DYNAMIC_SYMBOLS),
_targetLayout(layout) {}
void sortSymbols() override {
typedef typename DynamicSymbolTable<ELFT>::SymbolEntry SymbolEntry;
std::stable_sort(this->_symbolTable.begin(), this->_symbolTable.end(),
[this](const SymbolEntry &A, const SymbolEntry &B) {
if (A._symbol.getBinding() != STB_GLOBAL &&
B._symbol.getBinding() != STB_GLOBAL)
return A._symbol.getBinding() < B._symbol.getBinding();
return _targetLayout.getGOTSection().compare(A._atom, B._atom);
});
}
void finalize() override {
const auto &pltSection = _targetLayout.getPLTSection();
// Under some conditions a dynamic symbol table record should hold a symbol
// value of the corresponding PLT entry. For details look at the PLT entry
// creation code in the class MipsRelocationPass. Let's update atomLayout
// fields for such symbols.
for (auto &ste : this->_symbolTable) {
if (!ste._atom || ste._atomLayout)
continue;
auto *layout = pltSection.findPLTLayout(ste._atom);
if (layout) {
ste._symbol.st_value = layout->_virtualAddr;
ste._symbol.st_other |= ELF::STO_MIPS_PLT;
}
}
DynamicSymbolTable<Mips32ElELFType>::finalize();
}
private:
MipsTargetLayout<ELFT> &_targetLayout;
};
} // end namespace elf
} // end namespace lld
#endif
|
