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comparison lld/ELF/Target.cpp @ 150:1d019706d866

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LLVM10
author anatofuz
date Thu, 13 Feb 2020 15:10:13 +0900
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children 0572611fdcc8
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147:c2174574ed3a 150:1d019706d866
1 //===- Target.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 // Machine-specific things, such as applying relocations, creation of
10 // GOT or PLT entries, etc., are handled in this file.
11 //
12 // Refer the ELF spec for the single letter variables, S, A or P, used
13 // in this file.
14 //
15 // Some functions defined in this file has "relaxTls" as part of their names.
16 // They do peephole optimization for TLS variables by rewriting instructions.
17 // They are not part of the ABI but optional optimization, so you can skip
18 // them if you are not interested in how TLS variables are optimized.
19 // See the following paper for the details.
20 //
21 // Ulrich Drepper, ELF Handling For Thread-Local Storage
22 // http://www.akkadia.org/drepper/tls.pdf
23 //
24 //===----------------------------------------------------------------------===//
25
26 #include "Target.h"
27 #include "InputFiles.h"
28 #include "OutputSections.h"
29 #include "SymbolTable.h"
30 #include "Symbols.h"
31 #include "SyntheticSections.h"
32 #include "lld/Common/ErrorHandler.h"
33 #include "llvm/Object/ELF.h"
34
35 using namespace llvm;
36 using namespace llvm::object;
37 using namespace llvm::ELF;
38
39 namespace lld {
40 std::string toString(elf::RelType type) {
41 StringRef s = getELFRelocationTypeName(elf::config->emachine, type);
42 if (s == "Unknown")
43 return ("Unknown (" + Twine(type) + ")").str();
44 return std::string(s);
45 }
46
47 namespace elf {
48 const TargetInfo *target;
49
50 TargetInfo *getTarget() {
51 switch (config->emachine) {
52 case EM_386:
53 case EM_IAMCU:
54 return getX86TargetInfo();
55 case EM_AARCH64:
56 return getAArch64TargetInfo();
57 case EM_AMDGPU:
58 return getAMDGPUTargetInfo();
59 case EM_ARM:
60 return getARMTargetInfo();
61 case EM_AVR:
62 return getAVRTargetInfo();
63 case EM_HEXAGON:
64 return getHexagonTargetInfo();
65 case EM_MIPS:
66 switch (config->ekind) {
67 case ELF32LEKind:
68 return getMipsTargetInfo<ELF32LE>();
69 case ELF32BEKind:
70 return getMipsTargetInfo<ELF32BE>();
71 case ELF64LEKind:
72 return getMipsTargetInfo<ELF64LE>();
73 case ELF64BEKind:
74 return getMipsTargetInfo<ELF64BE>();
75 default:
76 llvm_unreachable("unsupported MIPS target");
77 }
78 case EM_MSP430:
79 return getMSP430TargetInfo();
80 case EM_PPC:
81 return getPPCTargetInfo();
82 case EM_PPC64:
83 return getPPC64TargetInfo();
84 case EM_RISCV:
85 return getRISCVTargetInfo();
86 case EM_SPARCV9:
87 return getSPARCV9TargetInfo();
88 case EM_X86_64:
89 return getX86_64TargetInfo();
90 }
91 llvm_unreachable("unknown target machine");
92 }
93
94 template <class ELFT> static ErrorPlace getErrPlace(const uint8_t *loc) {
95 assert(loc != nullptr);
96 for (InputSectionBase *d : inputSections) {
97 auto *isec = cast<InputSection>(d);
98 if (!isec->getParent() || (isec->type & SHT_NOBITS))
99 continue;
100
101 const uint8_t *isecLoc =
102 Out::bufferStart
103 ? (Out::bufferStart + isec->getParent()->offset + isec->outSecOff)
104 : isec->data().data();
105 if (isecLoc == nullptr) {
106 assert(isa<SyntheticSection>(isec) && "No data but not synthetic?");
107 continue;
108 }
109 if (isecLoc <= loc && loc < isecLoc + isec->getSize())
110 return {isec, isec->template getLocation<ELFT>(loc - isecLoc) + ": "};
111 }
112 return {};
113 }
114
115 ErrorPlace getErrorPlace(const uint8_t *loc) {
116 switch (config->ekind) {
117 case ELF32LEKind:
118 return getErrPlace<ELF32LE>(loc);
119 case ELF32BEKind:
120 return getErrPlace<ELF32BE>(loc);
121 case ELF64LEKind:
122 return getErrPlace<ELF64LE>(loc);
123 case ELF64BEKind:
124 return getErrPlace<ELF64BE>(loc);
125 default:
126 llvm_unreachable("unknown ELF type");
127 }
128 }
129
130 TargetInfo::~TargetInfo() {}
131
132 int64_t TargetInfo::getImplicitAddend(const uint8_t *buf, RelType type) const {
133 return 0;
134 }
135
136 bool TargetInfo::usesOnlyLowPageBits(RelType type) const { return false; }
137
138 bool TargetInfo::needsThunk(RelExpr expr, RelType type, const InputFile *file,
139 uint64_t branchAddr, const Symbol &s,
140 int64_t a) const {
141 return false;
142 }
143
144 bool TargetInfo::adjustPrologueForCrossSplitStack(uint8_t *loc, uint8_t *end,
145 uint8_t stOther) const {
146 llvm_unreachable("Target doesn't support split stacks.");
147 }
148
149 bool TargetInfo::inBranchRange(RelType type, uint64_t src, uint64_t dst) const {
150 return true;
151 }
152
153 RelExpr TargetInfo::adjustRelaxExpr(RelType type, const uint8_t *data,
154 RelExpr expr) const {
155 return expr;
156 }
157
158 void TargetInfo::relaxGot(uint8_t *loc, const Relocation &rel,
159 uint64_t val) const {
160 llvm_unreachable("Should not have claimed to be relaxable");
161 }
162
163 void TargetInfo::relaxTlsGdToLe(uint8_t *loc, const Relocation &rel,
164 uint64_t val) const {
165 llvm_unreachable("Should not have claimed to be relaxable");
166 }
167
168 void TargetInfo::relaxTlsGdToIe(uint8_t *loc, const Relocation &rel,
169 uint64_t val) const {
170 llvm_unreachable("Should not have claimed to be relaxable");
171 }
172
173 void TargetInfo::relaxTlsIeToLe(uint8_t *loc, const Relocation &rel,
174 uint64_t val) const {
175 llvm_unreachable("Should not have claimed to be relaxable");
176 }
177
178 void TargetInfo::relaxTlsLdToLe(uint8_t *loc, const Relocation &rel,
179 uint64_t val) const {
180 llvm_unreachable("Should not have claimed to be relaxable");
181 }
182
183 uint64_t TargetInfo::getImageBase() const {
184 // Use -image-base if set. Fall back to the target default if not.
185 if (config->imageBase)
186 return *config->imageBase;
187 return config->isPic ? 0 : defaultImageBase;
188 }
189
190 } // namespace elf
191 } // namespace lld