1 //===- Target.cpp ---------------------------------------------------------===//
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // Machine-specific things, such as applying relocations, creation of
11 // GOT or PLT entries, etc., are handled in this file.
13 // Refer the ELF spec for the single letter variables, S, A or P, used
16 // Some functions defined in this file has "relaxTls" as part of their names.
17 // They do peephole optimization for TLS variables by rewriting instructions.
18 // They are not part of the ABI but optional optimization, so you can skip
19 // them if you are not interested in how TLS variables are optimized.
20 // See the following paper for the details.
22 // Ulrich Drepper, ELF Handling For Thread-Local Storage
23 // http://www.akkadia.org/drepper/tls.pdf
25 //===----------------------------------------------------------------------===//
28 #include "InputFiles.h"
29 #include "OutputSections.h"
30 #include "SymbolTable.h"
32 #include "lld/Common/ErrorHandler.h"
33 #include "llvm/Object/ELF.h"
36 using namespace llvm::object;
37 using namespace llvm::ELF;
39 using namespace lld::elf;
41 TargetInfo *elf::Target;
43 std::string lld::toString(RelType Type) {
44 StringRef S = getELFRelocationTypeName(elf::Config->EMachine, Type);
46 return ("Unknown (" + Twine(Type) + ")").str();
50 TargetInfo *elf::getTarget() {
51 switch (Config->EMachine) {
54 return getX86TargetInfo();
56 return getAArch64TargetInfo();
58 return getAMDGPUTargetInfo();
60 return getARMTargetInfo();
62 return getAVRTargetInfo();
64 switch (Config->EKind) {
66 return getMipsTargetInfo<ELF32LE>();
68 return getMipsTargetInfo<ELF32BE>();
70 return getMipsTargetInfo<ELF64LE>();
72 return getMipsTargetInfo<ELF64BE>();
74 fatal("unsupported MIPS target");
77 return getPPCTargetInfo();
79 return getPPC64TargetInfo();
81 return getSPARCV9TargetInfo();
83 if (Config->EKind == ELF32LEKind)
84 return getX32TargetInfo();
85 return getX86_64TargetInfo();
87 fatal("unknown target machine");
90 template <class ELFT> static std::string getErrorLoc(const uint8_t *Loc) {
91 for (InputSectionBase *D : InputSections) {
92 auto *IS = dyn_cast<InputSection>(D);
93 if (!IS || !IS->getParent())
96 uint8_t *ISLoc = IS->getParent()->Loc + IS->OutSecOff;
97 if (ISLoc <= Loc && Loc < ISLoc + IS->getSize())
98 return IS->template getLocation<ELFT>(Loc - ISLoc) + ": ";
103 std::string elf::getErrorLocation(const uint8_t *Loc) {
104 switch (Config->EKind) {
106 return getErrorLoc<ELF32LE>(Loc);
108 return getErrorLoc<ELF32BE>(Loc);
110 return getErrorLoc<ELF64LE>(Loc);
112 return getErrorLoc<ELF64BE>(Loc);
114 llvm_unreachable("unknown ELF type");
118 TargetInfo::~TargetInfo() {}
120 int64_t TargetInfo::getImplicitAddend(const uint8_t *Buf, RelType Type) const {
124 bool TargetInfo::usesOnlyLowPageBits(RelType Type) const { return false; }
126 bool TargetInfo::needsThunk(RelExpr Expr, RelType Type, const InputFile *File,
127 uint64_t BranchAddr, const Symbol &S) const {
131 bool TargetInfo::inBranchRange(RelType Type, uint64_t Src, uint64_t Dst) const {
135 void TargetInfo::writeIgotPlt(uint8_t *Buf, const Symbol &S) const {
139 RelExpr TargetInfo::adjustRelaxExpr(RelType Type, const uint8_t *Data,
140 RelExpr Expr) const {
144 void TargetInfo::relaxGot(uint8_t *Loc, uint64_t Val) const {
145 llvm_unreachable("Should not have claimed to be relaxable");
148 void TargetInfo::relaxTlsGdToLe(uint8_t *Loc, RelType Type,
149 uint64_t Val) const {
150 llvm_unreachable("Should not have claimed to be relaxable");
153 void TargetInfo::relaxTlsGdToIe(uint8_t *Loc, RelType Type,
154 uint64_t Val) const {
155 llvm_unreachable("Should not have claimed to be relaxable");
158 void TargetInfo::relaxTlsIeToLe(uint8_t *Loc, RelType Type,
159 uint64_t Val) const {
160 llvm_unreachable("Should not have claimed to be relaxable");
163 void TargetInfo::relaxTlsLdToLe(uint8_t *Loc, RelType Type,
164 uint64_t Val) const {
165 llvm_unreachable("Should not have claimed to be relaxable");
168 uint64_t TargetInfo::getImageBase() {
169 // Use -image-base if set. Fall back to the target default if not.
170 if (Config->ImageBase)
171 return *Config->ImageBase;
172 return Config->Pic ? 0 : DefaultImageBase;