1 //===- Target.cpp ---------------------------------------------------------===// 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 // Machine-specific things, such as applying relocations, creation of 11 // GOT or PLT entries, etc., are handled in this file. 12 // 13 // Refer the ELF spec for the single letter variables, S, A or P, used 14 // in this file. 15 // 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. 21 // 22 // Ulrich Drepper, ELF Handling For Thread-Local Storage 23 // http://www.akkadia.org/drepper/tls.pdf 24 // 25 //===----------------------------------------------------------------------===// 26 27 #include "Target.h" 28 #include "Error.h" 29 #include "InputFiles.h" 30 #include "OutputSections.h" 31 #include "Symbols.h" 32 #include "SyntheticSections.h" 33 #include "Thunks.h" 34 #include "Writer.h" 35 36 #include "llvm/ADT/ArrayRef.h" 37 #include "llvm/Object/ELF.h" 38 #include "llvm/Support/Endian.h" 39 #include "llvm/Support/ELF.h" 40 41 using namespace llvm; 42 using namespace llvm::object; 43 using namespace llvm::support::endian; 44 using namespace llvm::ELF; 45 46 namespace lld { 47 namespace elf { 48 49 TargetInfo *Target; 50 51 static void or32le(uint8_t *P, int32_t V) { write32le(P, read32le(P) | V); } 52 static void or32be(uint8_t *P, int32_t V) { write32be(P, read32be(P) | V); } 53 54 StringRef getRelName(uint32_t Type) { 55 return getELFRelocationTypeName(Config->EMachine, Type); 56 } 57 58 template <unsigned N> static void checkInt(int64_t V, uint32_t Type) { 59 if (!isInt<N>(V)) 60 error("relocation " + getRelName(Type) + " out of range"); 61 } 62 63 template <unsigned N> static void checkUInt(uint64_t V, uint32_t Type) { 64 if (!isUInt<N>(V)) 65 error("relocation " + getRelName(Type) + " out of range"); 66 } 67 68 template <unsigned N> static void checkIntUInt(uint64_t V, uint32_t Type) { 69 if (!isInt<N>(V) && !isUInt<N>(V)) 70 error("relocation " + getRelName(Type) + " out of range"); 71 } 72 73 template <unsigned N> static void checkAlignment(uint64_t V, uint32_t Type) { 74 if ((V & (N - 1)) != 0) 75 error("improper alignment for relocation " + getRelName(Type)); 76 } 77 78 static void errorDynRel(uint32_t Type) { 79 error("relocation " + getRelName(Type) + 80 " cannot be used against shared object; recompile with -fPIC."); 81 } 82 83 namespace { 84 class X86TargetInfo final : public TargetInfo { 85 public: 86 X86TargetInfo(); 87 RelExpr getRelExpr(uint32_t Type, const SymbolBody &S) const override; 88 uint64_t getImplicitAddend(const uint8_t *Buf, uint32_t Type) const override; 89 void writeGotPltHeader(uint8_t *Buf) const override; 90 uint32_t getDynRel(uint32_t Type) const override; 91 bool isTlsLocalDynamicRel(uint32_t Type) const override; 92 bool isTlsGlobalDynamicRel(uint32_t Type) const override; 93 bool isTlsInitialExecRel(uint32_t Type) const override; 94 void writeGotPlt(uint8_t *Buf, const SymbolBody &S) const override; 95 void writePltHeader(uint8_t *Buf) const override; 96 void writePlt(uint8_t *Buf, uint64_t GotEntryAddr, uint64_t PltEntryAddr, 97 int32_t Index, unsigned RelOff) const override; 98 void relocateOne(uint8_t *Loc, uint32_t Type, uint64_t Val) const override; 99 100 RelExpr adjustRelaxExpr(uint32_t Type, const uint8_t *Data, 101 RelExpr Expr) const override; 102 void relaxTlsGdToIe(uint8_t *Loc, uint32_t Type, uint64_t Val) const override; 103 void relaxTlsGdToLe(uint8_t *Loc, uint32_t Type, uint64_t Val) const override; 104 void relaxTlsIeToLe(uint8_t *Loc, uint32_t Type, uint64_t Val) const override; 105 void relaxTlsLdToLe(uint8_t *Loc, uint32_t Type, uint64_t Val) const override; 106 }; 107 108 template <class ELFT> class X86_64TargetInfo final : public TargetInfo { 109 public: 110 X86_64TargetInfo(); 111 RelExpr getRelExpr(uint32_t Type, const SymbolBody &S) const override; 112 uint32_t getDynRel(uint32_t Type) const override; 113 bool isTlsLocalDynamicRel(uint32_t Type) const override; 114 bool isTlsGlobalDynamicRel(uint32_t Type) const override; 115 bool isTlsInitialExecRel(uint32_t Type) const override; 116 void writeGotPltHeader(uint8_t *Buf) const override; 117 void writeGotPlt(uint8_t *Buf, const SymbolBody &S) const override; 118 void writePltHeader(uint8_t *Buf) const override; 119 void writePlt(uint8_t *Buf, uint64_t GotEntryAddr, uint64_t PltEntryAddr, 120 int32_t Index, unsigned RelOff) const override; 121 void relocateOne(uint8_t *Loc, uint32_t Type, uint64_t Val) const override; 122 123 RelExpr adjustRelaxExpr(uint32_t Type, const uint8_t *Data, 124 RelExpr Expr) const override; 125 void relaxGot(uint8_t *Loc, uint64_t Val) const override; 126 void relaxTlsGdToIe(uint8_t *Loc, uint32_t Type, uint64_t Val) const override; 127 void relaxTlsGdToLe(uint8_t *Loc, uint32_t Type, uint64_t Val) const override; 128 void relaxTlsIeToLe(uint8_t *Loc, uint32_t Type, uint64_t Val) const override; 129 void relaxTlsLdToLe(uint8_t *Loc, uint32_t Type, uint64_t Val) const override; 130 131 private: 132 void relaxGotNoPic(uint8_t *Loc, uint64_t Val, uint8_t Op, 133 uint8_t ModRm) const; 134 }; 135 136 class PPCTargetInfo final : public TargetInfo { 137 public: 138 PPCTargetInfo(); 139 void relocateOne(uint8_t *Loc, uint32_t Type, uint64_t Val) const override; 140 RelExpr getRelExpr(uint32_t Type, const SymbolBody &S) const override; 141 }; 142 143 class PPC64TargetInfo final : public TargetInfo { 144 public: 145 PPC64TargetInfo(); 146 RelExpr getRelExpr(uint32_t Type, const SymbolBody &S) const override; 147 void writePlt(uint8_t *Buf, uint64_t GotEntryAddr, uint64_t PltEntryAddr, 148 int32_t Index, unsigned RelOff) const override; 149 void relocateOne(uint8_t *Loc, uint32_t Type, uint64_t Val) const override; 150 }; 151 152 class AArch64TargetInfo final : public TargetInfo { 153 public: 154 AArch64TargetInfo(); 155 RelExpr getRelExpr(uint32_t Type, const SymbolBody &S) const override; 156 uint32_t getDynRel(uint32_t Type) const override; 157 bool isTlsInitialExecRel(uint32_t Type) const override; 158 void writeGotPlt(uint8_t *Buf, const SymbolBody &S) const override; 159 void writePltHeader(uint8_t *Buf) const override; 160 void writePlt(uint8_t *Buf, uint64_t GotEntryAddr, uint64_t PltEntryAddr, 161 int32_t Index, unsigned RelOff) const override; 162 bool usesOnlyLowPageBits(uint32_t Type) const override; 163 void relocateOne(uint8_t *Loc, uint32_t Type, uint64_t Val) const override; 164 RelExpr adjustRelaxExpr(uint32_t Type, const uint8_t *Data, 165 RelExpr Expr) const override; 166 void relaxTlsGdToLe(uint8_t *Loc, uint32_t Type, uint64_t Val) const override; 167 void relaxTlsGdToIe(uint8_t *Loc, uint32_t Type, uint64_t Val) const override; 168 void relaxTlsIeToLe(uint8_t *Loc, uint32_t Type, uint64_t Val) const override; 169 }; 170 171 class AMDGPUTargetInfo final : public TargetInfo { 172 public: 173 AMDGPUTargetInfo(); 174 void relocateOne(uint8_t *Loc, uint32_t Type, uint64_t Val) const override; 175 RelExpr getRelExpr(uint32_t Type, const SymbolBody &S) const override; 176 }; 177 178 class ARMTargetInfo final : public TargetInfo { 179 public: 180 ARMTargetInfo(); 181 RelExpr getRelExpr(uint32_t Type, const SymbolBody &S) const override; 182 uint32_t getDynRel(uint32_t Type) const override; 183 uint64_t getImplicitAddend(const uint8_t *Buf, uint32_t Type) const override; 184 bool isTlsLocalDynamicRel(uint32_t Type) const override; 185 bool isTlsGlobalDynamicRel(uint32_t Type) const override; 186 bool isTlsInitialExecRel(uint32_t Type) const override; 187 void writeGotPlt(uint8_t *Buf, const SymbolBody &S) const override; 188 void writePltHeader(uint8_t *Buf) const override; 189 void writePlt(uint8_t *Buf, uint64_t GotEntryAddr, uint64_t PltEntryAddr, 190 int32_t Index, unsigned RelOff) const override; 191 RelExpr getThunkExpr(RelExpr Expr, uint32_t RelocType, const InputFile &File, 192 const SymbolBody &S) const override; 193 void relocateOne(uint8_t *Loc, uint32_t Type, uint64_t Val) const override; 194 }; 195 196 template <class ELFT> class MipsTargetInfo final : public TargetInfo { 197 public: 198 MipsTargetInfo(); 199 RelExpr getRelExpr(uint32_t Type, const SymbolBody &S) const override; 200 uint64_t getImplicitAddend(const uint8_t *Buf, uint32_t Type) const override; 201 uint32_t getDynRel(uint32_t Type) const override; 202 bool isTlsLocalDynamicRel(uint32_t Type) const override; 203 bool isTlsGlobalDynamicRel(uint32_t Type) const override; 204 void writeGotPlt(uint8_t *Buf, const SymbolBody &S) const override; 205 void writePltHeader(uint8_t *Buf) const override; 206 void writePlt(uint8_t *Buf, uint64_t GotEntryAddr, uint64_t PltEntryAddr, 207 int32_t Index, unsigned RelOff) const override; 208 RelExpr getThunkExpr(RelExpr Expr, uint32_t RelocType, const InputFile &File, 209 const SymbolBody &S) const override; 210 void relocateOne(uint8_t *Loc, uint32_t Type, uint64_t Val) const override; 211 bool usesOnlyLowPageBits(uint32_t Type) const override; 212 }; 213 } // anonymous namespace 214 215 TargetInfo *createTarget() { 216 switch (Config->EMachine) { 217 case EM_386: 218 case EM_IAMCU: 219 return new X86TargetInfo(); 220 case EM_AARCH64: 221 return new AArch64TargetInfo(); 222 case EM_AMDGPU: 223 return new AMDGPUTargetInfo(); 224 case EM_ARM: 225 return new ARMTargetInfo(); 226 case EM_MIPS: 227 switch (Config->EKind) { 228 case ELF32LEKind: 229 return new MipsTargetInfo<ELF32LE>(); 230 case ELF32BEKind: 231 return new MipsTargetInfo<ELF32BE>(); 232 case ELF64LEKind: 233 return new MipsTargetInfo<ELF64LE>(); 234 case ELF64BEKind: 235 return new MipsTargetInfo<ELF64BE>(); 236 default: 237 fatal("unsupported MIPS target"); 238 } 239 case EM_PPC: 240 return new PPCTargetInfo(); 241 case EM_PPC64: 242 return new PPC64TargetInfo(); 243 case EM_X86_64: 244 if (Config->EKind == ELF32LEKind) 245 return new X86_64TargetInfo<ELF32LE>(); 246 return new X86_64TargetInfo<ELF64LE>(); 247 } 248 fatal("unknown target machine"); 249 } 250 251 TargetInfo::~TargetInfo() {} 252 253 uint64_t TargetInfo::getImplicitAddend(const uint8_t *Buf, 254 uint32_t Type) const { 255 return 0; 256 } 257 258 bool TargetInfo::usesOnlyLowPageBits(uint32_t Type) const { return false; } 259 260 RelExpr TargetInfo::getThunkExpr(RelExpr Expr, uint32_t RelocType, 261 const InputFile &File, 262 const SymbolBody &S) const { 263 return Expr; 264 } 265 266 bool TargetInfo::isTlsInitialExecRel(uint32_t Type) const { return false; } 267 268 bool TargetInfo::isTlsLocalDynamicRel(uint32_t Type) const { return false; } 269 270 bool TargetInfo::isTlsGlobalDynamicRel(uint32_t Type) const { return false; } 271 272 RelExpr TargetInfo::adjustRelaxExpr(uint32_t Type, const uint8_t *Data, 273 RelExpr Expr) const { 274 return Expr; 275 } 276 277 void TargetInfo::relaxGot(uint8_t *Loc, uint64_t Val) const { 278 llvm_unreachable("Should not have claimed to be relaxable"); 279 } 280 281 void TargetInfo::relaxTlsGdToLe(uint8_t *Loc, uint32_t Type, 282 uint64_t Val) const { 283 llvm_unreachable("Should not have claimed to be relaxable"); 284 } 285 286 void TargetInfo::relaxTlsGdToIe(uint8_t *Loc, uint32_t Type, 287 uint64_t Val) const { 288 llvm_unreachable("Should not have claimed to be relaxable"); 289 } 290 291 void TargetInfo::relaxTlsIeToLe(uint8_t *Loc, uint32_t Type, 292 uint64_t Val) const { 293 llvm_unreachable("Should not have claimed to be relaxable"); 294 } 295 296 void TargetInfo::relaxTlsLdToLe(uint8_t *Loc, uint32_t Type, 297 uint64_t Val) const { 298 llvm_unreachable("Should not have claimed to be relaxable"); 299 } 300 301 X86TargetInfo::X86TargetInfo() { 302 CopyRel = R_386_COPY; 303 GotRel = R_386_GLOB_DAT; 304 PltRel = R_386_JUMP_SLOT; 305 IRelativeRel = R_386_IRELATIVE; 306 RelativeRel = R_386_RELATIVE; 307 TlsGotRel = R_386_TLS_TPOFF; 308 TlsModuleIndexRel = R_386_TLS_DTPMOD32; 309 TlsOffsetRel = R_386_TLS_DTPOFF32; 310 GotEntrySize = 4; 311 GotPltEntrySize = 4; 312 PltEntrySize = 16; 313 PltHeaderSize = 16; 314 TlsGdRelaxSkip = 2; 315 } 316 317 RelExpr X86TargetInfo::getRelExpr(uint32_t Type, const SymbolBody &S) const { 318 switch (Type) { 319 default: 320 return R_ABS; 321 case R_386_TLS_GD: 322 return R_TLSGD; 323 case R_386_TLS_LDM: 324 return R_TLSLD; 325 case R_386_PLT32: 326 return R_PLT_PC; 327 case R_386_PC32: 328 return R_PC; 329 case R_386_GOTPC: 330 return R_GOTONLY_PC_FROM_END; 331 case R_386_TLS_IE: 332 return R_GOT; 333 case R_386_GOT32: 334 case R_386_GOT32X: 335 case R_386_TLS_GOTIE: 336 return R_GOT_FROM_END; 337 case R_386_GOTOFF: 338 return R_GOTREL_FROM_END; 339 case R_386_TLS_LE: 340 return R_TLS; 341 case R_386_TLS_LE_32: 342 return R_NEG_TLS; 343 } 344 } 345 346 RelExpr X86TargetInfo::adjustRelaxExpr(uint32_t Type, const uint8_t *Data, 347 RelExpr Expr) const { 348 switch (Expr) { 349 default: 350 return Expr; 351 case R_RELAX_TLS_GD_TO_IE: 352 return R_RELAX_TLS_GD_TO_IE_END; 353 case R_RELAX_TLS_GD_TO_LE: 354 return R_RELAX_TLS_GD_TO_LE_NEG; 355 } 356 } 357 358 void X86TargetInfo::writeGotPltHeader(uint8_t *Buf) const { 359 write32le(Buf, In<ELF32LE>::Dynamic->getVA()); 360 } 361 362 void X86TargetInfo::writeGotPlt(uint8_t *Buf, const SymbolBody &S) const { 363 // Entries in .got.plt initially points back to the corresponding 364 // PLT entries with a fixed offset to skip the first instruction. 365 write32le(Buf, S.getPltVA<ELF32LE>() + 6); 366 } 367 368 uint32_t X86TargetInfo::getDynRel(uint32_t Type) const { 369 if (Type == R_386_TLS_LE) 370 return R_386_TLS_TPOFF; 371 if (Type == R_386_TLS_LE_32) 372 return R_386_TLS_TPOFF32; 373 return Type; 374 } 375 376 bool X86TargetInfo::isTlsGlobalDynamicRel(uint32_t Type) const { 377 return Type == R_386_TLS_GD; 378 } 379 380 bool X86TargetInfo::isTlsLocalDynamicRel(uint32_t Type) const { 381 return Type == R_386_TLS_LDO_32 || Type == R_386_TLS_LDM; 382 } 383 384 bool X86TargetInfo::isTlsInitialExecRel(uint32_t Type) const { 385 return Type == R_386_TLS_IE || Type == R_386_TLS_GOTIE; 386 } 387 388 void X86TargetInfo::writePltHeader(uint8_t *Buf) const { 389 // Executable files and shared object files have 390 // separate procedure linkage tables. 391 if (Config->Pic) { 392 const uint8_t V[] = { 393 0xff, 0xb3, 0x04, 0x00, 0x00, 0x00, // pushl 4(%ebx) 394 0xff, 0xa3, 0x08, 0x00, 0x00, 0x00, // jmp *8(%ebx) 395 0x90, 0x90, 0x90, 0x90 // nop; nop; nop; nop 396 }; 397 memcpy(Buf, V, sizeof(V)); 398 return; 399 } 400 401 const uint8_t PltData[] = { 402 0xff, 0x35, 0x00, 0x00, 0x00, 0x00, // pushl (GOT+4) 403 0xff, 0x25, 0x00, 0x00, 0x00, 0x00, // jmp *(GOT+8) 404 0x90, 0x90, 0x90, 0x90 // nop; nop; nop; nop 405 }; 406 memcpy(Buf, PltData, sizeof(PltData)); 407 uint32_t Got = In<ELF32LE>::GotPlt->getVA(); 408 write32le(Buf + 2, Got + 4); 409 write32le(Buf + 8, Got + 8); 410 } 411 412 void X86TargetInfo::writePlt(uint8_t *Buf, uint64_t GotEntryAddr, 413 uint64_t PltEntryAddr, int32_t Index, 414 unsigned RelOff) const { 415 const uint8_t Inst[] = { 416 0xff, 0x00, 0x00, 0x00, 0x00, 0x00, // jmp *foo_in_GOT|*foo@GOT(%ebx) 417 0x68, 0x00, 0x00, 0x00, 0x00, // pushl $reloc_offset 418 0xe9, 0x00, 0x00, 0x00, 0x00 // jmp .PLT0@PC 419 }; 420 memcpy(Buf, Inst, sizeof(Inst)); 421 422 // jmp *foo@GOT(%ebx) or jmp *foo_in_GOT 423 Buf[1] = Config->Pic ? 0xa3 : 0x25; 424 uint32_t Got = In<ELF32LE>::GotPlt->getVA(); 425 write32le(Buf + 2, Config->Shared ? GotEntryAddr - Got : GotEntryAddr); 426 write32le(Buf + 7, RelOff); 427 write32le(Buf + 12, -Index * PltEntrySize - PltHeaderSize - 16); 428 } 429 430 uint64_t X86TargetInfo::getImplicitAddend(const uint8_t *Buf, 431 uint32_t Type) const { 432 switch (Type) { 433 default: 434 return 0; 435 case R_386_32: 436 case R_386_GOT32: 437 case R_386_GOT32X: 438 case R_386_GOTOFF: 439 case R_386_GOTPC: 440 case R_386_PC32: 441 case R_386_PLT32: 442 case R_386_TLS_LE: 443 return read32le(Buf); 444 } 445 } 446 447 void X86TargetInfo::relocateOne(uint8_t *Loc, uint32_t Type, 448 uint64_t Val) const { 449 checkInt<32>(Val, Type); 450 write32le(Loc, Val); 451 } 452 453 void X86TargetInfo::relaxTlsGdToLe(uint8_t *Loc, uint32_t Type, 454 uint64_t Val) const { 455 // Convert 456 // leal x@tlsgd(, %ebx, 1), 457 // call __tls_get_addr@plt 458 // to 459 // movl %gs:0,%eax 460 // subl $x@ntpoff,%eax 461 const uint8_t Inst[] = { 462 0x65, 0xa1, 0x00, 0x00, 0x00, 0x00, // movl %gs:0, %eax 463 0x81, 0xe8, 0x00, 0x00, 0x00, 0x00 // subl 0(%ebx), %eax 464 }; 465 memcpy(Loc - 3, Inst, sizeof(Inst)); 466 relocateOne(Loc + 5, R_386_32, Val); 467 } 468 469 void X86TargetInfo::relaxTlsGdToIe(uint8_t *Loc, uint32_t Type, 470 uint64_t Val) const { 471 // Convert 472 // leal x@tlsgd(, %ebx, 1), 473 // call __tls_get_addr@plt 474 // to 475 // movl %gs:0, %eax 476 // addl x@gotntpoff(%ebx), %eax 477 const uint8_t Inst[] = { 478 0x65, 0xa1, 0x00, 0x00, 0x00, 0x00, // movl %gs:0, %eax 479 0x03, 0x83, 0x00, 0x00, 0x00, 0x00 // addl 0(%ebx), %eax 480 }; 481 memcpy(Loc - 3, Inst, sizeof(Inst)); 482 relocateOne(Loc + 5, R_386_32, Val); 483 } 484 485 // In some conditions, relocations can be optimized to avoid using GOT. 486 // This function does that for Initial Exec to Local Exec case. 487 void X86TargetInfo::relaxTlsIeToLe(uint8_t *Loc, uint32_t Type, 488 uint64_t Val) const { 489 // Ulrich's document section 6.2 says that @gotntpoff can 490 // be used with MOVL or ADDL instructions. 491 // @indntpoff is similar to @gotntpoff, but for use in 492 // position dependent code. 493 uint8_t Reg = (Loc[-1] >> 3) & 7; 494 495 if (Type == R_386_TLS_IE) { 496 if (Loc[-1] == 0xa1) { 497 // "movl foo@indntpoff,%eax" -> "movl $foo,%eax" 498 // This case is different from the generic case below because 499 // this is a 5 byte instruction while below is 6 bytes. 500 Loc[-1] = 0xb8; 501 } else if (Loc[-2] == 0x8b) { 502 // "movl foo@indntpoff,%reg" -> "movl $foo,%reg" 503 Loc[-2] = 0xc7; 504 Loc[-1] = 0xc0 | Reg; 505 } else { 506 // "addl foo@indntpoff,%reg" -> "addl $foo,%reg" 507 Loc[-2] = 0x81; 508 Loc[-1] = 0xc0 | Reg; 509 } 510 } else { 511 assert(Type == R_386_TLS_GOTIE); 512 if (Loc[-2] == 0x8b) { 513 // "movl foo@gottpoff(%rip),%reg" -> "movl $foo,%reg" 514 Loc[-2] = 0xc7; 515 Loc[-1] = 0xc0 | Reg; 516 } else { 517 // "addl foo@gotntpoff(%rip),%reg" -> "leal foo(%reg),%reg" 518 Loc[-2] = 0x8d; 519 Loc[-1] = 0x80 | (Reg << 3) | Reg; 520 } 521 } 522 relocateOne(Loc, R_386_TLS_LE, Val); 523 } 524 525 void X86TargetInfo::relaxTlsLdToLe(uint8_t *Loc, uint32_t Type, 526 uint64_t Val) const { 527 if (Type == R_386_TLS_LDO_32) { 528 relocateOne(Loc, R_386_TLS_LE, Val); 529 return; 530 } 531 532 // Convert 533 // leal foo(%reg),%eax 534 // call ___tls_get_addr 535 // to 536 // movl %gs:0,%eax 537 // nop 538 // leal 0(%esi,1),%esi 539 const uint8_t Inst[] = { 540 0x65, 0xa1, 0x00, 0x00, 0x00, 0x00, // movl %gs:0,%eax 541 0x90, // nop 542 0x8d, 0x74, 0x26, 0x00 // leal 0(%esi,1),%esi 543 }; 544 memcpy(Loc - 2, Inst, sizeof(Inst)); 545 } 546 547 template <class ELFT> X86_64TargetInfo<ELFT>::X86_64TargetInfo() { 548 CopyRel = R_X86_64_COPY; 549 GotRel = R_X86_64_GLOB_DAT; 550 PltRel = R_X86_64_JUMP_SLOT; 551 RelativeRel = R_X86_64_RELATIVE; 552 IRelativeRel = R_X86_64_IRELATIVE; 553 TlsGotRel = R_X86_64_TPOFF64; 554 TlsModuleIndexRel = R_X86_64_DTPMOD64; 555 TlsOffsetRel = R_X86_64_DTPOFF64; 556 GotEntrySize = 8; 557 GotPltEntrySize = 8; 558 PltEntrySize = 16; 559 PltHeaderSize = 16; 560 TlsGdRelaxSkip = 2; 561 } 562 563 template <class ELFT> 564 RelExpr X86_64TargetInfo<ELFT>::getRelExpr(uint32_t Type, 565 const SymbolBody &S) const { 566 switch (Type) { 567 default: 568 return R_ABS; 569 case R_X86_64_TPOFF32: 570 return R_TLS; 571 case R_X86_64_TLSLD: 572 return R_TLSLD_PC; 573 case R_X86_64_TLSGD: 574 return R_TLSGD_PC; 575 case R_X86_64_SIZE32: 576 case R_X86_64_SIZE64: 577 return R_SIZE; 578 case R_X86_64_PLT32: 579 return R_PLT_PC; 580 case R_X86_64_PC32: 581 case R_X86_64_PC64: 582 return R_PC; 583 case R_X86_64_GOT32: 584 return R_GOT_FROM_END; 585 case R_X86_64_GOTPCREL: 586 case R_X86_64_GOTPCRELX: 587 case R_X86_64_REX_GOTPCRELX: 588 case R_X86_64_GOTTPOFF: 589 return R_GOT_PC; 590 } 591 } 592 593 template <class ELFT> 594 void X86_64TargetInfo<ELFT>::writeGotPltHeader(uint8_t *Buf) const { 595 // The first entry holds the value of _DYNAMIC. It is not clear why that is 596 // required, but it is documented in the psabi and the glibc dynamic linker 597 // seems to use it (note that this is relevant for linking ld.so, not any 598 // other program). 599 write64le(Buf, In<ELFT>::Dynamic->getVA()); 600 } 601 602 template <class ELFT> 603 void X86_64TargetInfo<ELFT>::writeGotPlt(uint8_t *Buf, 604 const SymbolBody &S) const { 605 // See comments in X86TargetInfo::writeGotPlt. 606 write32le(Buf, S.getPltVA<ELFT>() + 6); 607 } 608 609 template <class ELFT> 610 void X86_64TargetInfo<ELFT>::writePltHeader(uint8_t *Buf) const { 611 const uint8_t PltData[] = { 612 0xff, 0x35, 0x00, 0x00, 0x00, 0x00, // pushq GOT+8(%rip) 613 0xff, 0x25, 0x00, 0x00, 0x00, 0x00, // jmp *GOT+16(%rip) 614 0x0f, 0x1f, 0x40, 0x00 // nopl 0x0(rax) 615 }; 616 memcpy(Buf, PltData, sizeof(PltData)); 617 uint64_t Got = In<ELFT>::GotPlt->getVA(); 618 uint64_t Plt = Out<ELFT>::Plt->Addr; 619 write32le(Buf + 2, Got - Plt + 2); // GOT+8 620 write32le(Buf + 8, Got - Plt + 4); // GOT+16 621 } 622 623 template <class ELFT> 624 void X86_64TargetInfo<ELFT>::writePlt(uint8_t *Buf, uint64_t GotEntryAddr, 625 uint64_t PltEntryAddr, int32_t Index, 626 unsigned RelOff) const { 627 const uint8_t Inst[] = { 628 0xff, 0x25, 0x00, 0x00, 0x00, 0x00, // jmpq *got(%rip) 629 0x68, 0x00, 0x00, 0x00, 0x00, // pushq <relocation index> 630 0xe9, 0x00, 0x00, 0x00, 0x00 // jmpq plt[0] 631 }; 632 memcpy(Buf, Inst, sizeof(Inst)); 633 634 write32le(Buf + 2, GotEntryAddr - PltEntryAddr - 6); 635 write32le(Buf + 7, Index); 636 write32le(Buf + 12, -Index * PltEntrySize - PltHeaderSize - 16); 637 } 638 639 template <class ELFT> 640 uint32_t X86_64TargetInfo<ELFT>::getDynRel(uint32_t Type) const { 641 if (Type == R_X86_64_PC32 || Type == R_X86_64_32) 642 errorDynRel(Type); 643 return Type; 644 } 645 646 template <class ELFT> 647 bool X86_64TargetInfo<ELFT>::isTlsInitialExecRel(uint32_t Type) const { 648 return Type == R_X86_64_GOTTPOFF; 649 } 650 651 template <class ELFT> 652 bool X86_64TargetInfo<ELFT>::isTlsGlobalDynamicRel(uint32_t Type) const { 653 return Type == R_X86_64_TLSGD; 654 } 655 656 template <class ELFT> 657 bool X86_64TargetInfo<ELFT>::isTlsLocalDynamicRel(uint32_t Type) const { 658 return Type == R_X86_64_DTPOFF32 || Type == R_X86_64_DTPOFF64 || 659 Type == R_X86_64_TLSLD; 660 } 661 662 template <class ELFT> 663 void X86_64TargetInfo<ELFT>::relaxTlsGdToLe(uint8_t *Loc, uint32_t Type, 664 uint64_t Val) const { 665 // Convert 666 // .byte 0x66 667 // leaq x@tlsgd(%rip), %rdi 668 // .word 0x6666 669 // rex64 670 // call __tls_get_addr@plt 671 // to 672 // mov %fs:0x0,%rax 673 // lea x@tpoff,%rax 674 const uint8_t Inst[] = { 675 0x64, 0x48, 0x8b, 0x04, 0x25, 0x00, 0x00, 0x00, 0x00, // mov %fs:0x0,%rax 676 0x48, 0x8d, 0x80, 0x00, 0x00, 0x00, 0x00 // lea x@tpoff,%rax 677 }; 678 memcpy(Loc - 4, Inst, sizeof(Inst)); 679 // The original code used a pc relative relocation and so we have to 680 // compensate for the -4 in had in the addend. 681 relocateOne(Loc + 8, R_X86_64_TPOFF32, Val + 4); 682 } 683 684 template <class ELFT> 685 void X86_64TargetInfo<ELFT>::relaxTlsGdToIe(uint8_t *Loc, uint32_t Type, 686 uint64_t Val) const { 687 // Convert 688 // .byte 0x66 689 // leaq x@tlsgd(%rip), %rdi 690 // .word 0x6666 691 // rex64 692 // call __tls_get_addr@plt 693 // to 694 // mov %fs:0x0,%rax 695 // addq x@tpoff,%rax 696 const uint8_t Inst[] = { 697 0x64, 0x48, 0x8b, 0x04, 0x25, 0x00, 0x00, 0x00, 0x00, // mov %fs:0x0,%rax 698 0x48, 0x03, 0x05, 0x00, 0x00, 0x00, 0x00 // addq x@tpoff,%rax 699 }; 700 memcpy(Loc - 4, Inst, sizeof(Inst)); 701 // Both code sequences are PC relatives, but since we are moving the constant 702 // forward by 8 bytes we have to subtract the value by 8. 703 relocateOne(Loc + 8, R_X86_64_PC32, Val - 8); 704 } 705 706 // In some conditions, R_X86_64_GOTTPOFF relocation can be optimized to 707 // R_X86_64_TPOFF32 so that it does not use GOT. 708 template <class ELFT> 709 void X86_64TargetInfo<ELFT>::relaxTlsIeToLe(uint8_t *Loc, uint32_t Type, 710 uint64_t Val) const { 711 uint8_t *Inst = Loc - 3; 712 uint8_t Reg = Loc[-1] >> 3; 713 uint8_t *RegSlot = Loc - 1; 714 715 // Note that ADD with RSP or R12 is converted to ADD instead of LEA 716 // because LEA with these registers needs 4 bytes to encode and thus 717 // wouldn't fit the space. 718 719 if (memcmp(Inst, "\x48\x03\x25", 3) == 0) { 720 // "addq foo@gottpoff(%rip),%rsp" -> "addq $foo,%rsp" 721 memcpy(Inst, "\x48\x81\xc4", 3); 722 } else if (memcmp(Inst, "\x4c\x03\x25", 3) == 0) { 723 // "addq foo@gottpoff(%rip),%r12" -> "addq $foo,%r12" 724 memcpy(Inst, "\x49\x81\xc4", 3); 725 } else if (memcmp(Inst, "\x4c\x03", 2) == 0) { 726 // "addq foo@gottpoff(%rip),%r[8-15]" -> "leaq foo(%r[8-15]),%r[8-15]" 727 memcpy(Inst, "\x4d\x8d", 2); 728 *RegSlot = 0x80 | (Reg << 3) | Reg; 729 } else if (memcmp(Inst, "\x48\x03", 2) == 0) { 730 // "addq foo@gottpoff(%rip),%reg -> "leaq foo(%reg),%reg" 731 memcpy(Inst, "\x48\x8d", 2); 732 *RegSlot = 0x80 | (Reg << 3) | Reg; 733 } else if (memcmp(Inst, "\x4c\x8b", 2) == 0) { 734 // "movq foo@gottpoff(%rip),%r[8-15]" -> "movq $foo,%r[8-15]" 735 memcpy(Inst, "\x49\xc7", 2); 736 *RegSlot = 0xc0 | Reg; 737 } else if (memcmp(Inst, "\x48\x8b", 2) == 0) { 738 // "movq foo@gottpoff(%rip),%reg" -> "movq $foo,%reg" 739 memcpy(Inst, "\x48\xc7", 2); 740 *RegSlot = 0xc0 | Reg; 741 } else { 742 fatal("R_X86_64_GOTTPOFF must be used in MOVQ or ADDQ instructions only"); 743 } 744 745 // The original code used a PC relative relocation. 746 // Need to compensate for the -4 it had in the addend. 747 relocateOne(Loc, R_X86_64_TPOFF32, Val + 4); 748 } 749 750 template <class ELFT> 751 void X86_64TargetInfo<ELFT>::relaxTlsLdToLe(uint8_t *Loc, uint32_t Type, 752 uint64_t Val) const { 753 // Convert 754 // leaq bar@tlsld(%rip), %rdi 755 // callq __tls_get_addr@PLT 756 // leaq bar@dtpoff(%rax), %rcx 757 // to 758 // .word 0x6666 759 // .byte 0x66 760 // mov %fs:0,%rax 761 // leaq bar@tpoff(%rax), %rcx 762 if (Type == R_X86_64_DTPOFF64) { 763 write64le(Loc, Val); 764 return; 765 } 766 if (Type == R_X86_64_DTPOFF32) { 767 relocateOne(Loc, R_X86_64_TPOFF32, Val); 768 return; 769 } 770 771 const uint8_t Inst[] = { 772 0x66, 0x66, // .word 0x6666 773 0x66, // .byte 0x66 774 0x64, 0x48, 0x8b, 0x04, 0x25, 0x00, 0x00, 0x00, 0x00 // mov %fs:0,%rax 775 }; 776 memcpy(Loc - 3, Inst, sizeof(Inst)); 777 } 778 779 template <class ELFT> 780 void X86_64TargetInfo<ELFT>::relocateOne(uint8_t *Loc, uint32_t Type, 781 uint64_t Val) const { 782 switch (Type) { 783 case R_X86_64_32: 784 checkUInt<32>(Val, Type); 785 write32le(Loc, Val); 786 break; 787 case R_X86_64_32S: 788 case R_X86_64_TPOFF32: 789 case R_X86_64_GOT32: 790 case R_X86_64_GOTPCREL: 791 case R_X86_64_GOTPCRELX: 792 case R_X86_64_REX_GOTPCRELX: 793 case R_X86_64_PC32: 794 case R_X86_64_GOTTPOFF: 795 case R_X86_64_PLT32: 796 case R_X86_64_TLSGD: 797 case R_X86_64_TLSLD: 798 case R_X86_64_DTPOFF32: 799 case R_X86_64_SIZE32: 800 checkInt<32>(Val, Type); 801 write32le(Loc, Val); 802 break; 803 case R_X86_64_64: 804 case R_X86_64_DTPOFF64: 805 case R_X86_64_SIZE64: 806 case R_X86_64_PC64: 807 write64le(Loc, Val); 808 break; 809 default: 810 fatal("unrecognized reloc " + Twine(Type)); 811 } 812 } 813 814 template <class ELFT> 815 RelExpr X86_64TargetInfo<ELFT>::adjustRelaxExpr(uint32_t Type, 816 const uint8_t *Data, 817 RelExpr RelExpr) const { 818 if (Type != R_X86_64_GOTPCRELX && Type != R_X86_64_REX_GOTPCRELX) 819 return RelExpr; 820 const uint8_t Op = Data[-2]; 821 const uint8_t ModRm = Data[-1]; 822 // FIXME: When PIC is disabled and foo is defined locally in the 823 // lower 32 bit address space, memory operand in mov can be converted into 824 // immediate operand. Otherwise, mov must be changed to lea. We support only 825 // latter relaxation at this moment. 826 if (Op == 0x8b) 827 return R_RELAX_GOT_PC; 828 // Relax call and jmp. 829 if (Op == 0xff && (ModRm == 0x15 || ModRm == 0x25)) 830 return R_RELAX_GOT_PC; 831 832 // Relaxation of test, adc, add, and, cmp, or, sbb, sub, xor. 833 // If PIC then no relaxation is available. 834 // We also don't relax test/binop instructions without REX byte, 835 // they are 32bit operations and not common to have. 836 assert(Type == R_X86_64_REX_GOTPCRELX); 837 return Config->Pic ? RelExpr : R_RELAX_GOT_PC_NOPIC; 838 } 839 840 // A subset of relaxations can only be applied for no-PIC. This method 841 // handles such relaxations. Instructions encoding information was taken from: 842 // "Intel 64 and IA-32 Architectures Software Developer's Manual V2" 843 // (http://www.intel.com/content/dam/www/public/us/en/documents/manuals/ 844 // 64-ia-32-architectures-software-developer-instruction-set-reference-manual-325383.pdf) 845 template <class ELFT> 846 void X86_64TargetInfo<ELFT>::relaxGotNoPic(uint8_t *Loc, uint64_t Val, 847 uint8_t Op, uint8_t ModRm) const { 848 const uint8_t Rex = Loc[-3]; 849 // Convert "test %reg, foo@GOTPCREL(%rip)" to "test $foo, %reg". 850 if (Op == 0x85) { 851 // See "TEST-Logical Compare" (4-428 Vol. 2B), 852 // TEST r/m64, r64 uses "full" ModR / M byte (no opcode extension). 853 854 // ModR/M byte has form XX YYY ZZZ, where 855 // YYY is MODRM.reg(register 2), ZZZ is MODRM.rm(register 1). 856 // XX has different meanings: 857 // 00: The operand's memory address is in reg1. 858 // 01: The operand's memory address is reg1 + a byte-sized displacement. 859 // 10: The operand's memory address is reg1 + a word-sized displacement. 860 // 11: The operand is reg1 itself. 861 // If an instruction requires only one operand, the unused reg2 field 862 // holds extra opcode bits rather than a register code 863 // 0xC0 == 11 000 000 binary. 864 // 0x38 == 00 111 000 binary. 865 // We transfer reg2 to reg1 here as operand. 866 // See "2.1.3 ModR/M and SIB Bytes" (Vol. 2A 2-3). 867 Loc[-1] = 0xc0 | (ModRm & 0x38) >> 3; // ModR/M byte. 868 869 // Change opcode from TEST r/m64, r64 to TEST r/m64, imm32 870 // See "TEST-Logical Compare" (4-428 Vol. 2B). 871 Loc[-2] = 0xf7; 872 873 // Move R bit to the B bit in REX byte. 874 // REX byte is encoded as 0100WRXB, where 875 // 0100 is 4bit fixed pattern. 876 // REX.W When 1, a 64-bit operand size is used. Otherwise, when 0, the 877 // default operand size is used (which is 32-bit for most but not all 878 // instructions). 879 // REX.R This 1-bit value is an extension to the MODRM.reg field. 880 // REX.X This 1-bit value is an extension to the SIB.index field. 881 // REX.B This 1-bit value is an extension to the MODRM.rm field or the 882 // SIB.base field. 883 // See "2.2.1.2 More on REX Prefix Fields " (2-8 Vol. 2A). 884 Loc[-3] = (Rex & ~0x4) | (Rex & 0x4) >> 2; 885 relocateOne(Loc, R_X86_64_PC32, Val); 886 return; 887 } 888 889 // If we are here then we need to relax the adc, add, and, cmp, or, sbb, sub 890 // or xor operations. 891 892 // Convert "binop foo@GOTPCREL(%rip), %reg" to "binop $foo, %reg". 893 // Logic is close to one for test instruction above, but we also 894 // write opcode extension here, see below for details. 895 Loc[-1] = 0xc0 | (ModRm & 0x38) >> 3 | (Op & 0x3c); // ModR/M byte. 896 897 // Primary opcode is 0x81, opcode extension is one of: 898 // 000b = ADD, 001b is OR, 010b is ADC, 011b is SBB, 899 // 100b is AND, 101b is SUB, 110b is XOR, 111b is CMP. 900 // This value was wrote to MODRM.reg in a line above. 901 // See "3.2 INSTRUCTIONS (A-M)" (Vol. 2A 3-15), 902 // "INSTRUCTION SET REFERENCE, N-Z" (Vol. 2B 4-1) for 903 // descriptions about each operation. 904 Loc[-2] = 0x81; 905 Loc[-3] = (Rex & ~0x4) | (Rex & 0x4) >> 2; 906 relocateOne(Loc, R_X86_64_PC32, Val); 907 } 908 909 template <class ELFT> 910 void X86_64TargetInfo<ELFT>::relaxGot(uint8_t *Loc, uint64_t Val) const { 911 const uint8_t Op = Loc[-2]; 912 const uint8_t ModRm = Loc[-1]; 913 914 // Convert "mov foo@GOTPCREL(%rip),%reg" to "lea foo(%rip),%reg". 915 if (Op == 0x8b) { 916 Loc[-2] = 0x8d; 917 relocateOne(Loc, R_X86_64_PC32, Val); 918 return; 919 } 920 921 if (Op != 0xff) { 922 // We are relaxing a rip relative to an absolute, so compensate 923 // for the old -4 addend. 924 assert(!Config->Pic); 925 relaxGotNoPic(Loc, Val + 4, Op, ModRm); 926 return; 927 } 928 929 // Convert call/jmp instructions. 930 if (ModRm == 0x15) { 931 // ABI says we can convert "call *foo@GOTPCREL(%rip)" to "nop; call foo". 932 // Instead we convert to "addr32 call foo" where addr32 is an instruction 933 // prefix. That makes result expression to be a single instruction. 934 Loc[-2] = 0x67; // addr32 prefix 935 Loc[-1] = 0xe8; // call 936 relocateOne(Loc, R_X86_64_PC32, Val); 937 return; 938 } 939 940 // Convert "jmp *foo@GOTPCREL(%rip)" to "jmp foo; nop". 941 // jmp doesn't return, so it is fine to use nop here, it is just a stub. 942 assert(ModRm == 0x25); 943 Loc[-2] = 0xe9; // jmp 944 Loc[3] = 0x90; // nop 945 relocateOne(Loc - 1, R_X86_64_PC32, Val + 1); 946 } 947 948 // Relocation masks following the #lo(value), #hi(value), #ha(value), 949 // #higher(value), #highera(value), #highest(value), and #highesta(value) 950 // macros defined in section 4.5.1. Relocation Types of the PPC-elf64abi 951 // document. 952 static uint16_t applyPPCLo(uint64_t V) { return V; } 953 static uint16_t applyPPCHi(uint64_t V) { return V >> 16; } 954 static uint16_t applyPPCHa(uint64_t V) { return (V + 0x8000) >> 16; } 955 static uint16_t applyPPCHigher(uint64_t V) { return V >> 32; } 956 static uint16_t applyPPCHighera(uint64_t V) { return (V + 0x8000) >> 32; } 957 static uint16_t applyPPCHighest(uint64_t V) { return V >> 48; } 958 static uint16_t applyPPCHighesta(uint64_t V) { return (V + 0x8000) >> 48; } 959 960 PPCTargetInfo::PPCTargetInfo() {} 961 962 void PPCTargetInfo::relocateOne(uint8_t *Loc, uint32_t Type, 963 uint64_t Val) const { 964 switch (Type) { 965 case R_PPC_ADDR16_HA: 966 write16be(Loc, applyPPCHa(Val)); 967 break; 968 case R_PPC_ADDR16_LO: 969 write16be(Loc, applyPPCLo(Val)); 970 break; 971 case R_PPC_ADDR32: 972 case R_PPC_REL32: 973 write32be(Loc, Val); 974 break; 975 case R_PPC_REL24: 976 or32be(Loc, Val & 0x3FFFFFC); 977 break; 978 default: 979 fatal("unrecognized reloc " + Twine(Type)); 980 } 981 } 982 983 RelExpr PPCTargetInfo::getRelExpr(uint32_t Type, const SymbolBody &S) const { 984 switch (Type) { 985 case R_PPC_REL24: 986 case R_PPC_REL32: 987 return R_PC; 988 default: 989 return R_ABS; 990 } 991 } 992 993 PPC64TargetInfo::PPC64TargetInfo() { 994 PltRel = GotRel = R_PPC64_GLOB_DAT; 995 RelativeRel = R_PPC64_RELATIVE; 996 GotEntrySize = 8; 997 GotPltEntrySize = 8; 998 PltEntrySize = 32; 999 PltHeaderSize = 0; 1000 1001 // We need 64K pages (at least under glibc/Linux, the loader won't 1002 // set different permissions on a finer granularity than that). 1003 MaxPageSize = 65536; 1004 1005 // The PPC64 ELF ABI v1 spec, says: 1006 // 1007 // It is normally desirable to put segments with different characteristics 1008 // in separate 256 Mbyte portions of the address space, to give the 1009 // operating system full paging flexibility in the 64-bit address space. 1010 // 1011 // And because the lowest non-zero 256M boundary is 0x10000000, PPC64 linkers 1012 // use 0x10000000 as the starting address. 1013 DefaultImageBase = 0x10000000; 1014 } 1015 1016 static uint64_t PPC64TocOffset = 0x8000; 1017 1018 uint64_t getPPC64TocBase() { 1019 // The TOC consists of sections .got, .toc, .tocbss, .plt in that order. The 1020 // TOC starts where the first of these sections starts. We always create a 1021 // .got when we see a relocation that uses it, so for us the start is always 1022 // the .got. 1023 uint64_t TocVA = In<ELF64BE>::Got->getVA(); 1024 1025 // Per the ppc64-elf-linux ABI, The TOC base is TOC value plus 0x8000 1026 // thus permitting a full 64 Kbytes segment. Note that the glibc startup 1027 // code (crt1.o) assumes that you can get from the TOC base to the 1028 // start of the .toc section with only a single (signed) 16-bit relocation. 1029 return TocVA + PPC64TocOffset; 1030 } 1031 1032 RelExpr PPC64TargetInfo::getRelExpr(uint32_t Type, const SymbolBody &S) const { 1033 switch (Type) { 1034 default: 1035 return R_ABS; 1036 case R_PPC64_TOC16: 1037 case R_PPC64_TOC16_DS: 1038 case R_PPC64_TOC16_HA: 1039 case R_PPC64_TOC16_HI: 1040 case R_PPC64_TOC16_LO: 1041 case R_PPC64_TOC16_LO_DS: 1042 return R_GOTREL; 1043 case R_PPC64_TOC: 1044 return R_PPC_TOC; 1045 case R_PPC64_REL24: 1046 return R_PPC_PLT_OPD; 1047 } 1048 } 1049 1050 void PPC64TargetInfo::writePlt(uint8_t *Buf, uint64_t GotEntryAddr, 1051 uint64_t PltEntryAddr, int32_t Index, 1052 unsigned RelOff) const { 1053 uint64_t Off = GotEntryAddr - getPPC64TocBase(); 1054 1055 // FIXME: What we should do, in theory, is get the offset of the function 1056 // descriptor in the .opd section, and use that as the offset from %r2 (the 1057 // TOC-base pointer). Instead, we have the GOT-entry offset, and that will 1058 // be a pointer to the function descriptor in the .opd section. Using 1059 // this scheme is simpler, but requires an extra indirection per PLT dispatch. 1060 1061 write32be(Buf, 0xf8410028); // std %r2, 40(%r1) 1062 write32be(Buf + 4, 0x3d620000 | applyPPCHa(Off)); // addis %r11, %r2, X@ha 1063 write32be(Buf + 8, 0xe98b0000 | applyPPCLo(Off)); // ld %r12, X@l(%r11) 1064 write32be(Buf + 12, 0xe96c0000); // ld %r11,0(%r12) 1065 write32be(Buf + 16, 0x7d6903a6); // mtctr %r11 1066 write32be(Buf + 20, 0xe84c0008); // ld %r2,8(%r12) 1067 write32be(Buf + 24, 0xe96c0010); // ld %r11,16(%r12) 1068 write32be(Buf + 28, 0x4e800420); // bctr 1069 } 1070 1071 static std::pair<uint32_t, uint64_t> toAddr16Rel(uint32_t Type, uint64_t Val) { 1072 uint64_t V = Val - PPC64TocOffset; 1073 switch (Type) { 1074 case R_PPC64_TOC16: 1075 return {R_PPC64_ADDR16, V}; 1076 case R_PPC64_TOC16_DS: 1077 return {R_PPC64_ADDR16_DS, V}; 1078 case R_PPC64_TOC16_HA: 1079 return {R_PPC64_ADDR16_HA, V}; 1080 case R_PPC64_TOC16_HI: 1081 return {R_PPC64_ADDR16_HI, V}; 1082 case R_PPC64_TOC16_LO: 1083 return {R_PPC64_ADDR16_LO, V}; 1084 case R_PPC64_TOC16_LO_DS: 1085 return {R_PPC64_ADDR16_LO_DS, V}; 1086 default: 1087 return {Type, Val}; 1088 } 1089 } 1090 1091 void PPC64TargetInfo::relocateOne(uint8_t *Loc, uint32_t Type, 1092 uint64_t Val) const { 1093 // For a TOC-relative relocation, proceed in terms of the corresponding 1094 // ADDR16 relocation type. 1095 std::tie(Type, Val) = toAddr16Rel(Type, Val); 1096 1097 switch (Type) { 1098 case R_PPC64_ADDR14: { 1099 checkAlignment<4>(Val, Type); 1100 // Preserve the AA/LK bits in the branch instruction 1101 uint8_t AALK = Loc[3]; 1102 write16be(Loc + 2, (AALK & 3) | (Val & 0xfffc)); 1103 break; 1104 } 1105 case R_PPC64_ADDR16: 1106 checkInt<16>(Val, Type); 1107 write16be(Loc, Val); 1108 break; 1109 case R_PPC64_ADDR16_DS: 1110 checkInt<16>(Val, Type); 1111 write16be(Loc, (read16be(Loc) & 3) | (Val & ~3)); 1112 break; 1113 case R_PPC64_ADDR16_HA: 1114 case R_PPC64_REL16_HA: 1115 write16be(Loc, applyPPCHa(Val)); 1116 break; 1117 case R_PPC64_ADDR16_HI: 1118 case R_PPC64_REL16_HI: 1119 write16be(Loc, applyPPCHi(Val)); 1120 break; 1121 case R_PPC64_ADDR16_HIGHER: 1122 write16be(Loc, applyPPCHigher(Val)); 1123 break; 1124 case R_PPC64_ADDR16_HIGHERA: 1125 write16be(Loc, applyPPCHighera(Val)); 1126 break; 1127 case R_PPC64_ADDR16_HIGHEST: 1128 write16be(Loc, applyPPCHighest(Val)); 1129 break; 1130 case R_PPC64_ADDR16_HIGHESTA: 1131 write16be(Loc, applyPPCHighesta(Val)); 1132 break; 1133 case R_PPC64_ADDR16_LO: 1134 write16be(Loc, applyPPCLo(Val)); 1135 break; 1136 case R_PPC64_ADDR16_LO_DS: 1137 case R_PPC64_REL16_LO: 1138 write16be(Loc, (read16be(Loc) & 3) | (applyPPCLo(Val) & ~3)); 1139 break; 1140 case R_PPC64_ADDR32: 1141 case R_PPC64_REL32: 1142 checkInt<32>(Val, Type); 1143 write32be(Loc, Val); 1144 break; 1145 case R_PPC64_ADDR64: 1146 case R_PPC64_REL64: 1147 case R_PPC64_TOC: 1148 write64be(Loc, Val); 1149 break; 1150 case R_PPC64_REL24: { 1151 uint32_t Mask = 0x03FFFFFC; 1152 checkInt<24>(Val, Type); 1153 write32be(Loc, (read32be(Loc) & ~Mask) | (Val & Mask)); 1154 break; 1155 } 1156 default: 1157 fatal("unrecognized reloc " + Twine(Type)); 1158 } 1159 } 1160 1161 AArch64TargetInfo::AArch64TargetInfo() { 1162 CopyRel = R_AARCH64_COPY; 1163 RelativeRel = R_AARCH64_RELATIVE; 1164 IRelativeRel = R_AARCH64_IRELATIVE; 1165 GotRel = R_AARCH64_GLOB_DAT; 1166 PltRel = R_AARCH64_JUMP_SLOT; 1167 TlsDescRel = R_AARCH64_TLSDESC; 1168 TlsGotRel = R_AARCH64_TLS_TPREL64; 1169 GotEntrySize = 8; 1170 GotPltEntrySize = 8; 1171 PltEntrySize = 16; 1172 PltHeaderSize = 32; 1173 MaxPageSize = 65536; 1174 1175 // It doesn't seem to be documented anywhere, but tls on aarch64 uses variant 1176 // 1 of the tls structures and the tcb size is 16. 1177 TcbSize = 16; 1178 } 1179 1180 RelExpr AArch64TargetInfo::getRelExpr(uint32_t Type, 1181 const SymbolBody &S) const { 1182 switch (Type) { 1183 default: 1184 return R_ABS; 1185 case R_AARCH64_TLSDESC_ADR_PAGE21: 1186 return R_TLSDESC_PAGE; 1187 case R_AARCH64_TLSDESC_LD64_LO12_NC: 1188 case R_AARCH64_TLSDESC_ADD_LO12_NC: 1189 return R_TLSDESC; 1190 case R_AARCH64_TLSDESC_CALL: 1191 return R_TLSDESC_CALL; 1192 case R_AARCH64_TLSLE_ADD_TPREL_HI12: 1193 case R_AARCH64_TLSLE_ADD_TPREL_LO12_NC: 1194 return R_TLS; 1195 case R_AARCH64_CALL26: 1196 case R_AARCH64_CONDBR19: 1197 case R_AARCH64_JUMP26: 1198 case R_AARCH64_TSTBR14: 1199 return R_PLT_PC; 1200 case R_AARCH64_PREL16: 1201 case R_AARCH64_PREL32: 1202 case R_AARCH64_PREL64: 1203 case R_AARCH64_ADR_PREL_LO21: 1204 return R_PC; 1205 case R_AARCH64_ADR_PREL_PG_HI21: 1206 return R_PAGE_PC; 1207 case R_AARCH64_LD64_GOT_LO12_NC: 1208 case R_AARCH64_TLSIE_LD64_GOTTPREL_LO12_NC: 1209 return R_GOT; 1210 case R_AARCH64_ADR_GOT_PAGE: 1211 case R_AARCH64_TLSIE_ADR_GOTTPREL_PAGE21: 1212 return R_GOT_PAGE_PC; 1213 } 1214 } 1215 1216 RelExpr AArch64TargetInfo::adjustRelaxExpr(uint32_t Type, const uint8_t *Data, 1217 RelExpr Expr) const { 1218 if (Expr == R_RELAX_TLS_GD_TO_IE) { 1219 if (Type == R_AARCH64_TLSDESC_ADR_PAGE21) 1220 return R_RELAX_TLS_GD_TO_IE_PAGE_PC; 1221 return R_RELAX_TLS_GD_TO_IE_ABS; 1222 } 1223 return Expr; 1224 } 1225 1226 bool AArch64TargetInfo::usesOnlyLowPageBits(uint32_t Type) const { 1227 switch (Type) { 1228 default: 1229 return false; 1230 case R_AARCH64_ADD_ABS_LO12_NC: 1231 case R_AARCH64_LD64_GOT_LO12_NC: 1232 case R_AARCH64_LDST128_ABS_LO12_NC: 1233 case R_AARCH64_LDST16_ABS_LO12_NC: 1234 case R_AARCH64_LDST32_ABS_LO12_NC: 1235 case R_AARCH64_LDST64_ABS_LO12_NC: 1236 case R_AARCH64_LDST8_ABS_LO12_NC: 1237 case R_AARCH64_TLSDESC_ADD_LO12_NC: 1238 case R_AARCH64_TLSDESC_LD64_LO12_NC: 1239 case R_AARCH64_TLSIE_LD64_GOTTPREL_LO12_NC: 1240 return true; 1241 } 1242 } 1243 1244 bool AArch64TargetInfo::isTlsInitialExecRel(uint32_t Type) const { 1245 return Type == R_AARCH64_TLSIE_ADR_GOTTPREL_PAGE21 || 1246 Type == R_AARCH64_TLSIE_LD64_GOTTPREL_LO12_NC; 1247 } 1248 1249 uint32_t AArch64TargetInfo::getDynRel(uint32_t Type) const { 1250 if (Type == R_AARCH64_ABS32 || Type == R_AARCH64_ABS64) 1251 return Type; 1252 // Keep it going with a dummy value so that we can find more reloc errors. 1253 errorDynRel(Type); 1254 return R_AARCH64_ABS32; 1255 } 1256 1257 void AArch64TargetInfo::writeGotPlt(uint8_t *Buf, const SymbolBody &) const { 1258 write64le(Buf, Out<ELF64LE>::Plt->Addr); 1259 } 1260 1261 static uint64_t getAArch64Page(uint64_t Expr) { 1262 return Expr & (~static_cast<uint64_t>(0xFFF)); 1263 } 1264 1265 void AArch64TargetInfo::writePltHeader(uint8_t *Buf) const { 1266 const uint8_t PltData[] = { 1267 0xf0, 0x7b, 0xbf, 0xa9, // stp x16, x30, [sp,#-16]! 1268 0x10, 0x00, 0x00, 0x90, // adrp x16, Page(&(.plt.got[2])) 1269 0x11, 0x02, 0x40, 0xf9, // ldr x17, [x16, Offset(&(.plt.got[2]))] 1270 0x10, 0x02, 0x00, 0x91, // add x16, x16, Offset(&(.plt.got[2])) 1271 0x20, 0x02, 0x1f, 0xd6, // br x17 1272 0x1f, 0x20, 0x03, 0xd5, // nop 1273 0x1f, 0x20, 0x03, 0xd5, // nop 1274 0x1f, 0x20, 0x03, 0xd5 // nop 1275 }; 1276 memcpy(Buf, PltData, sizeof(PltData)); 1277 1278 uint64_t Got = In<ELF64LE>::GotPlt->getVA(); 1279 uint64_t Plt = Out<ELF64LE>::Plt->Addr; 1280 relocateOne(Buf + 4, R_AARCH64_ADR_PREL_PG_HI21, 1281 getAArch64Page(Got + 16) - getAArch64Page(Plt + 4)); 1282 relocateOne(Buf + 8, R_AARCH64_LDST64_ABS_LO12_NC, Got + 16); 1283 relocateOne(Buf + 12, R_AARCH64_ADD_ABS_LO12_NC, Got + 16); 1284 } 1285 1286 void AArch64TargetInfo::writePlt(uint8_t *Buf, uint64_t GotEntryAddr, 1287 uint64_t PltEntryAddr, int32_t Index, 1288 unsigned RelOff) const { 1289 const uint8_t Inst[] = { 1290 0x10, 0x00, 0x00, 0x90, // adrp x16, Page(&(.plt.got[n])) 1291 0x11, 0x02, 0x40, 0xf9, // ldr x17, [x16, Offset(&(.plt.got[n]))] 1292 0x10, 0x02, 0x00, 0x91, // add x16, x16, Offset(&(.plt.got[n])) 1293 0x20, 0x02, 0x1f, 0xd6 // br x17 1294 }; 1295 memcpy(Buf, Inst, sizeof(Inst)); 1296 1297 relocateOne(Buf, R_AARCH64_ADR_PREL_PG_HI21, 1298 getAArch64Page(GotEntryAddr) - getAArch64Page(PltEntryAddr)); 1299 relocateOne(Buf + 4, R_AARCH64_LDST64_ABS_LO12_NC, GotEntryAddr); 1300 relocateOne(Buf + 8, R_AARCH64_ADD_ABS_LO12_NC, GotEntryAddr); 1301 } 1302 1303 static void updateAArch64Addr(uint8_t *L, uint64_t Imm) { 1304 uint32_t ImmLo = (Imm & 0x3) << 29; 1305 uint32_t ImmHi = (Imm & 0x1FFFFC) << 3; 1306 uint64_t Mask = (0x3 << 29) | (0x1FFFFC << 3); 1307 write32le(L, (read32le(L) & ~Mask) | ImmLo | ImmHi); 1308 } 1309 1310 static inline void updateAArch64Add(uint8_t *L, uint64_t Imm) { 1311 or32le(L, (Imm & 0xFFF) << 10); 1312 } 1313 1314 void AArch64TargetInfo::relocateOne(uint8_t *Loc, uint32_t Type, 1315 uint64_t Val) const { 1316 switch (Type) { 1317 case R_AARCH64_ABS16: 1318 case R_AARCH64_PREL16: 1319 checkIntUInt<16>(Val, Type); 1320 write16le(Loc, Val); 1321 break; 1322 case R_AARCH64_ABS32: 1323 case R_AARCH64_PREL32: 1324 checkIntUInt<32>(Val, Type); 1325 write32le(Loc, Val); 1326 break; 1327 case R_AARCH64_ABS64: 1328 case R_AARCH64_PREL64: 1329 write64le(Loc, Val); 1330 break; 1331 case R_AARCH64_ADD_ABS_LO12_NC: 1332 // This relocation stores 12 bits and there's no instruction 1333 // to do it. Instead, we do a 32 bits store of the value 1334 // of r_addend bitwise-or'ed Loc. This assumes that the addend 1335 // bits in Loc are zero. 1336 or32le(Loc, (Val & 0xFFF) << 10); 1337 break; 1338 case R_AARCH64_ADR_GOT_PAGE: 1339 case R_AARCH64_ADR_PREL_PG_HI21: 1340 case R_AARCH64_TLSIE_ADR_GOTTPREL_PAGE21: 1341 case R_AARCH64_TLSDESC_ADR_PAGE21: 1342 checkInt<33>(Val, Type); 1343 updateAArch64Addr(Loc, Val >> 12); 1344 break; 1345 case R_AARCH64_ADR_PREL_LO21: 1346 checkInt<21>(Val, Type); 1347 updateAArch64Addr(Loc, Val); 1348 break; 1349 case R_AARCH64_CALL26: 1350 case R_AARCH64_JUMP26: 1351 checkInt<28>(Val, Type); 1352 or32le(Loc, (Val & 0x0FFFFFFC) >> 2); 1353 break; 1354 case R_AARCH64_CONDBR19: 1355 checkInt<21>(Val, Type); 1356 or32le(Loc, (Val & 0x1FFFFC) << 3); 1357 break; 1358 case R_AARCH64_LD64_GOT_LO12_NC: 1359 case R_AARCH64_TLSIE_LD64_GOTTPREL_LO12_NC: 1360 case R_AARCH64_TLSDESC_LD64_LO12_NC: 1361 checkAlignment<8>(Val, Type); 1362 or32le(Loc, (Val & 0xFF8) << 7); 1363 break; 1364 case R_AARCH64_LDST128_ABS_LO12_NC: 1365 or32le(Loc, (Val & 0x0FF8) << 6); 1366 break; 1367 case R_AARCH64_LDST16_ABS_LO12_NC: 1368 or32le(Loc, (Val & 0x0FFC) << 9); 1369 break; 1370 case R_AARCH64_LDST8_ABS_LO12_NC: 1371 or32le(Loc, (Val & 0xFFF) << 10); 1372 break; 1373 case R_AARCH64_LDST32_ABS_LO12_NC: 1374 or32le(Loc, (Val & 0xFFC) << 8); 1375 break; 1376 case R_AARCH64_LDST64_ABS_LO12_NC: 1377 or32le(Loc, (Val & 0xFF8) << 7); 1378 break; 1379 case R_AARCH64_MOVW_UABS_G0_NC: 1380 or32le(Loc, (Val & 0xFFFF) << 5); 1381 break; 1382 case R_AARCH64_MOVW_UABS_G1_NC: 1383 or32le(Loc, (Val & 0xFFFF0000) >> 11); 1384 break; 1385 case R_AARCH64_MOVW_UABS_G2_NC: 1386 or32le(Loc, (Val & 0xFFFF00000000) >> 27); 1387 break; 1388 case R_AARCH64_MOVW_UABS_G3: 1389 or32le(Loc, (Val & 0xFFFF000000000000) >> 43); 1390 break; 1391 case R_AARCH64_TSTBR14: 1392 checkInt<16>(Val, Type); 1393 or32le(Loc, (Val & 0xFFFC) << 3); 1394 break; 1395 case R_AARCH64_TLSLE_ADD_TPREL_HI12: 1396 checkInt<24>(Val, Type); 1397 updateAArch64Add(Loc, Val >> 12); 1398 break; 1399 case R_AARCH64_TLSLE_ADD_TPREL_LO12_NC: 1400 case R_AARCH64_TLSDESC_ADD_LO12_NC: 1401 updateAArch64Add(Loc, Val); 1402 break; 1403 default: 1404 fatal("unrecognized reloc " + Twine(Type)); 1405 } 1406 } 1407 1408 void AArch64TargetInfo::relaxTlsGdToLe(uint8_t *Loc, uint32_t Type, 1409 uint64_t Val) const { 1410 // TLSDESC Global-Dynamic relocation are in the form: 1411 // adrp x0, :tlsdesc:v [R_AARCH64_TLSDESC_ADR_PAGE21] 1412 // ldr x1, [x0, #:tlsdesc_lo12:v [R_AARCH64_TLSDESC_LD64_LO12_NC] 1413 // add x0, x0, :tlsdesc_los:v [_AARCH64_TLSDESC_ADD_LO12_NC] 1414 // .tlsdesccall [R_AARCH64_TLSDESC_CALL] 1415 // blr x1 1416 // And it can optimized to: 1417 // movz x0, #0x0, lsl #16 1418 // movk x0, #0x10 1419 // nop 1420 // nop 1421 checkUInt<32>(Val, Type); 1422 1423 switch (Type) { 1424 case R_AARCH64_TLSDESC_ADD_LO12_NC: 1425 case R_AARCH64_TLSDESC_CALL: 1426 write32le(Loc, 0xd503201f); // nop 1427 return; 1428 case R_AARCH64_TLSDESC_ADR_PAGE21: 1429 write32le(Loc, 0xd2a00000 | (((Val >> 16) & 0xffff) << 5)); // movz 1430 return; 1431 case R_AARCH64_TLSDESC_LD64_LO12_NC: 1432 write32le(Loc, 0xf2800000 | ((Val & 0xffff) << 5)); // movk 1433 return; 1434 default: 1435 llvm_unreachable("unsupported relocation for TLS GD to LE relaxation"); 1436 } 1437 } 1438 1439 void AArch64TargetInfo::relaxTlsGdToIe(uint8_t *Loc, uint32_t Type, 1440 uint64_t Val) const { 1441 // TLSDESC Global-Dynamic relocation are in the form: 1442 // adrp x0, :tlsdesc:v [R_AARCH64_TLSDESC_ADR_PAGE21] 1443 // ldr x1, [x0, #:tlsdesc_lo12:v [R_AARCH64_TLSDESC_LD64_LO12_NC] 1444 // add x0, x0, :tlsdesc_los:v [_AARCH64_TLSDESC_ADD_LO12_NC] 1445 // .tlsdesccall [R_AARCH64_TLSDESC_CALL] 1446 // blr x1 1447 // And it can optimized to: 1448 // adrp x0, :gottprel:v 1449 // ldr x0, [x0, :gottprel_lo12:v] 1450 // nop 1451 // nop 1452 1453 switch (Type) { 1454 case R_AARCH64_TLSDESC_ADD_LO12_NC: 1455 case R_AARCH64_TLSDESC_CALL: 1456 write32le(Loc, 0xd503201f); // nop 1457 break; 1458 case R_AARCH64_TLSDESC_ADR_PAGE21: 1459 write32le(Loc, 0x90000000); // adrp 1460 relocateOne(Loc, R_AARCH64_TLSIE_ADR_GOTTPREL_PAGE21, Val); 1461 break; 1462 case R_AARCH64_TLSDESC_LD64_LO12_NC: 1463 write32le(Loc, 0xf9400000); // ldr 1464 relocateOne(Loc, R_AARCH64_TLSIE_LD64_GOTTPREL_LO12_NC, Val); 1465 break; 1466 default: 1467 llvm_unreachable("unsupported relocation for TLS GD to LE relaxation"); 1468 } 1469 } 1470 1471 void AArch64TargetInfo::relaxTlsIeToLe(uint8_t *Loc, uint32_t Type, 1472 uint64_t Val) const { 1473 checkUInt<32>(Val, Type); 1474 1475 if (Type == R_AARCH64_TLSIE_ADR_GOTTPREL_PAGE21) { 1476 // Generate MOVZ. 1477 uint32_t RegNo = read32le(Loc) & 0x1f; 1478 write32le(Loc, (0xd2a00000 | RegNo) | (((Val >> 16) & 0xffff) << 5)); 1479 return; 1480 } 1481 if (Type == R_AARCH64_TLSIE_LD64_GOTTPREL_LO12_NC) { 1482 // Generate MOVK. 1483 uint32_t RegNo = read32le(Loc) & 0x1f; 1484 write32le(Loc, (0xf2800000 | RegNo) | ((Val & 0xffff) << 5)); 1485 return; 1486 } 1487 llvm_unreachable("invalid relocation for TLS IE to LE relaxation"); 1488 } 1489 1490 AMDGPUTargetInfo::AMDGPUTargetInfo() { 1491 RelativeRel = R_AMDGPU_REL64; 1492 GotRel = R_AMDGPU_ABS64; 1493 GotEntrySize = 8; 1494 } 1495 1496 void AMDGPUTargetInfo::relocateOne(uint8_t *Loc, uint32_t Type, 1497 uint64_t Val) const { 1498 switch (Type) { 1499 case R_AMDGPU_ABS32: 1500 case R_AMDGPU_GOTPCREL: 1501 case R_AMDGPU_GOTPCREL32_LO: 1502 case R_AMDGPU_REL32: 1503 case R_AMDGPU_REL32_LO: 1504 write32le(Loc, Val); 1505 break; 1506 case R_AMDGPU_ABS64: 1507 write64le(Loc, Val); 1508 break; 1509 case R_AMDGPU_GOTPCREL32_HI: 1510 case R_AMDGPU_REL32_HI: 1511 write32le(Loc, Val >> 32); 1512 break; 1513 default: 1514 fatal("unrecognized reloc " + Twine(Type)); 1515 } 1516 } 1517 1518 RelExpr AMDGPUTargetInfo::getRelExpr(uint32_t Type, const SymbolBody &S) const { 1519 switch (Type) { 1520 case R_AMDGPU_ABS32: 1521 case R_AMDGPU_ABS64: 1522 return R_ABS; 1523 case R_AMDGPU_REL32: 1524 case R_AMDGPU_REL32_LO: 1525 case R_AMDGPU_REL32_HI: 1526 return R_PC; 1527 case R_AMDGPU_GOTPCREL: 1528 case R_AMDGPU_GOTPCREL32_LO: 1529 case R_AMDGPU_GOTPCREL32_HI: 1530 return R_GOT_PC; 1531 default: 1532 fatal("do not know how to handle relocation " + Twine(Type)); 1533 } 1534 } 1535 1536 ARMTargetInfo::ARMTargetInfo() { 1537 CopyRel = R_ARM_COPY; 1538 RelativeRel = R_ARM_RELATIVE; 1539 IRelativeRel = R_ARM_IRELATIVE; 1540 GotRel = R_ARM_GLOB_DAT; 1541 PltRel = R_ARM_JUMP_SLOT; 1542 TlsGotRel = R_ARM_TLS_TPOFF32; 1543 TlsModuleIndexRel = R_ARM_TLS_DTPMOD32; 1544 TlsOffsetRel = R_ARM_TLS_DTPOFF32; 1545 GotEntrySize = 4; 1546 GotPltEntrySize = 4; 1547 PltEntrySize = 16; 1548 PltHeaderSize = 20; 1549 // ARM uses Variant 1 TLS 1550 TcbSize = 8; 1551 NeedsThunks = true; 1552 } 1553 1554 RelExpr ARMTargetInfo::getRelExpr(uint32_t Type, const SymbolBody &S) const { 1555 switch (Type) { 1556 default: 1557 return R_ABS; 1558 case R_ARM_THM_JUMP11: 1559 return R_PC; 1560 case R_ARM_CALL: 1561 case R_ARM_JUMP24: 1562 case R_ARM_PC24: 1563 case R_ARM_PLT32: 1564 case R_ARM_PREL31: 1565 case R_ARM_THM_JUMP19: 1566 case R_ARM_THM_JUMP24: 1567 case R_ARM_THM_CALL: 1568 return R_PLT_PC; 1569 case R_ARM_GOTOFF32: 1570 // (S + A) - GOT_ORG 1571 return R_GOTREL; 1572 case R_ARM_GOT_BREL: 1573 // GOT(S) + A - GOT_ORG 1574 return R_GOT_OFF; 1575 case R_ARM_GOT_PREL: 1576 case R_ARM_TLS_IE32: 1577 // GOT(S) + A - P 1578 return R_GOT_PC; 1579 case R_ARM_TARGET1: 1580 return Config->Target1Rel ? R_PC : R_ABS; 1581 case R_ARM_TARGET2: 1582 if (Config->Target2 == Target2Policy::Rel) 1583 return R_PC; 1584 if (Config->Target2 == Target2Policy::Abs) 1585 return R_ABS; 1586 return R_GOT_PC; 1587 case R_ARM_TLS_GD32: 1588 return R_TLSGD_PC; 1589 case R_ARM_TLS_LDM32: 1590 return R_TLSLD_PC; 1591 case R_ARM_BASE_PREL: 1592 // B(S) + A - P 1593 // FIXME: currently B(S) assumed to be .got, this may not hold for all 1594 // platforms. 1595 return R_GOTONLY_PC; 1596 case R_ARM_MOVW_PREL_NC: 1597 case R_ARM_MOVT_PREL: 1598 case R_ARM_REL32: 1599 case R_ARM_THM_MOVW_PREL_NC: 1600 case R_ARM_THM_MOVT_PREL: 1601 return R_PC; 1602 case R_ARM_NONE: 1603 return R_HINT; 1604 case R_ARM_TLS_LE32: 1605 return R_TLS; 1606 } 1607 } 1608 1609 uint32_t ARMTargetInfo::getDynRel(uint32_t Type) const { 1610 if (Type == R_ARM_TARGET1 && !Config->Target1Rel) 1611 return R_ARM_ABS32; 1612 if (Type == R_ARM_ABS32) 1613 return Type; 1614 // Keep it going with a dummy value so that we can find more reloc errors. 1615 errorDynRel(Type); 1616 return R_ARM_ABS32; 1617 } 1618 1619 void ARMTargetInfo::writeGotPlt(uint8_t *Buf, const SymbolBody &) const { 1620 write32le(Buf, Out<ELF32LE>::Plt->Addr); 1621 } 1622 1623 void ARMTargetInfo::writePltHeader(uint8_t *Buf) const { 1624 const uint8_t PltData[] = { 1625 0x04, 0xe0, 0x2d, 0xe5, // str lr, [sp,#-4]! 1626 0x04, 0xe0, 0x9f, 0xe5, // ldr lr, L2 1627 0x0e, 0xe0, 0x8f, 0xe0, // L1: add lr, pc, lr 1628 0x08, 0xf0, 0xbe, 0xe5, // ldr pc, [lr, #8] 1629 0x00, 0x00, 0x00, 0x00, // L2: .word &(.got.plt) - L1 - 8 1630 }; 1631 memcpy(Buf, PltData, sizeof(PltData)); 1632 uint64_t GotPlt = In<ELF32LE>::GotPlt->getVA(); 1633 uint64_t L1 = Out<ELF32LE>::Plt->Addr + 8; 1634 write32le(Buf + 16, GotPlt - L1 - 8); 1635 } 1636 1637 void ARMTargetInfo::writePlt(uint8_t *Buf, uint64_t GotEntryAddr, 1638 uint64_t PltEntryAddr, int32_t Index, 1639 unsigned RelOff) const { 1640 // FIXME: Using simple code sequence with simple relocations. 1641 // There is a more optimal sequence but it requires support for the group 1642 // relocations. See ELF for the ARM Architecture Appendix A.3 1643 const uint8_t PltData[] = { 1644 0x04, 0xc0, 0x9f, 0xe5, // ldr ip, L2 1645 0x0f, 0xc0, 0x8c, 0xe0, // L1: add ip, ip, pc 1646 0x00, 0xf0, 0x9c, 0xe5, // ldr pc, [ip] 1647 0x00, 0x00, 0x00, 0x00, // L2: .word Offset(&(.plt.got) - L1 - 8 1648 }; 1649 memcpy(Buf, PltData, sizeof(PltData)); 1650 uint64_t L1 = PltEntryAddr + 4; 1651 write32le(Buf + 12, GotEntryAddr - L1 - 8); 1652 } 1653 1654 RelExpr ARMTargetInfo::getThunkExpr(RelExpr Expr, uint32_t RelocType, 1655 const InputFile &File, 1656 const SymbolBody &S) const { 1657 // If S is an undefined weak symbol we don't need a Thunk 1658 if (S.isUndefined()) 1659 return Expr; 1660 // A state change from ARM to Thumb and vice versa must go through an 1661 // interworking thunk if the relocation type is not R_ARM_CALL or 1662 // R_ARM_THM_CALL. 1663 switch (RelocType) { 1664 case R_ARM_PC24: 1665 case R_ARM_PLT32: 1666 case R_ARM_JUMP24: 1667 // Source is ARM, all PLT entries are ARM so no interworking required. 1668 // Otherwise we need to interwork if Symbol has bit 0 set (Thumb). 1669 if (Expr == R_PC && ((S.getVA<ELF32LE>() & 1) == 1)) 1670 return R_THUNK_PC; 1671 break; 1672 case R_ARM_THM_JUMP19: 1673 case R_ARM_THM_JUMP24: 1674 // Source is Thumb, all PLT entries are ARM so interworking is required. 1675 // Otherwise we need to interwork if Symbol has bit 0 clear (ARM). 1676 if (Expr == R_PLT_PC) 1677 return R_THUNK_PLT_PC; 1678 if ((S.getVA<ELF32LE>() & 1) == 0) 1679 return R_THUNK_PC; 1680 break; 1681 } 1682 return Expr; 1683 } 1684 1685 void ARMTargetInfo::relocateOne(uint8_t *Loc, uint32_t Type, 1686 uint64_t Val) const { 1687 switch (Type) { 1688 case R_ARM_ABS32: 1689 case R_ARM_BASE_PREL: 1690 case R_ARM_GOTOFF32: 1691 case R_ARM_GOT_BREL: 1692 case R_ARM_GOT_PREL: 1693 case R_ARM_REL32: 1694 case R_ARM_TARGET1: 1695 case R_ARM_TARGET2: 1696 case R_ARM_TLS_GD32: 1697 case R_ARM_TLS_IE32: 1698 case R_ARM_TLS_LDM32: 1699 case R_ARM_TLS_LDO32: 1700 case R_ARM_TLS_LE32: 1701 write32le(Loc, Val); 1702 break; 1703 case R_ARM_PREL31: 1704 checkInt<31>(Val, Type); 1705 write32le(Loc, (read32le(Loc) & 0x80000000) | (Val & ~0x80000000)); 1706 break; 1707 case R_ARM_CALL: 1708 // R_ARM_CALL is used for BL and BLX instructions, depending on the 1709 // value of bit 0 of Val, we must select a BL or BLX instruction 1710 if (Val & 1) { 1711 // If bit 0 of Val is 1 the target is Thumb, we must select a BLX. 1712 // The BLX encoding is 0xfa:H:imm24 where Val = imm24:H:'1' 1713 checkInt<26>(Val, Type); 1714 write32le(Loc, 0xfa000000 | // opcode 1715 ((Val & 2) << 23) | // H 1716 ((Val >> 2) & 0x00ffffff)); // imm24 1717 break; 1718 } 1719 if ((read32le(Loc) & 0xfe000000) == 0xfa000000) 1720 // BLX (always unconditional) instruction to an ARM Target, select an 1721 // unconditional BL. 1722 write32le(Loc, 0xeb000000 | (read32le(Loc) & 0x00ffffff)); 1723 // fall through as BL encoding is shared with B 1724 case R_ARM_JUMP24: 1725 case R_ARM_PC24: 1726 case R_ARM_PLT32: 1727 checkInt<26>(Val, Type); 1728 write32le(Loc, (read32le(Loc) & ~0x00ffffff) | ((Val >> 2) & 0x00ffffff)); 1729 break; 1730 case R_ARM_THM_JUMP11: 1731 checkInt<12>(Val, Type); 1732 write16le(Loc, (read32le(Loc) & 0xf800) | ((Val >> 1) & 0x07ff)); 1733 break; 1734 case R_ARM_THM_JUMP19: 1735 // Encoding T3: Val = S:J2:J1:imm6:imm11:0 1736 checkInt<21>(Val, Type); 1737 write16le(Loc, 1738 (read16le(Loc) & 0xfbc0) | // opcode cond 1739 ((Val >> 10) & 0x0400) | // S 1740 ((Val >> 12) & 0x003f)); // imm6 1741 write16le(Loc + 2, 1742 0x8000 | // opcode 1743 ((Val >> 8) & 0x0800) | // J2 1744 ((Val >> 5) & 0x2000) | // J1 1745 ((Val >> 1) & 0x07ff)); // imm11 1746 break; 1747 case R_ARM_THM_CALL: 1748 // R_ARM_THM_CALL is used for BL and BLX instructions, depending on the 1749 // value of bit 0 of Val, we must select a BL or BLX instruction 1750 if ((Val & 1) == 0) { 1751 // Ensure BLX destination is 4-byte aligned. As BLX instruction may 1752 // only be two byte aligned. This must be done before overflow check 1753 Val = alignTo(Val, 4); 1754 } 1755 // Bit 12 is 0 for BLX, 1 for BL 1756 write16le(Loc + 2, (read16le(Loc + 2) & ~0x1000) | (Val & 1) << 12); 1757 // Fall through as rest of encoding is the same as B.W 1758 case R_ARM_THM_JUMP24: 1759 // Encoding B T4, BL T1, BLX T2: Val = S:I1:I2:imm10:imm11:0 1760 // FIXME: Use of I1 and I2 require v6T2ops 1761 checkInt<25>(Val, Type); 1762 write16le(Loc, 1763 0xf000 | // opcode 1764 ((Val >> 14) & 0x0400) | // S 1765 ((Val >> 12) & 0x03ff)); // imm10 1766 write16le(Loc + 2, 1767 (read16le(Loc + 2) & 0xd000) | // opcode 1768 (((~(Val >> 10)) ^ (Val >> 11)) & 0x2000) | // J1 1769 (((~(Val >> 11)) ^ (Val >> 13)) & 0x0800) | // J2 1770 ((Val >> 1) & 0x07ff)); // imm11 1771 break; 1772 case R_ARM_MOVW_ABS_NC: 1773 case R_ARM_MOVW_PREL_NC: 1774 write32le(Loc, (read32le(Loc) & ~0x000f0fff) | ((Val & 0xf000) << 4) | 1775 (Val & 0x0fff)); 1776 break; 1777 case R_ARM_MOVT_ABS: 1778 case R_ARM_MOVT_PREL: 1779 checkInt<32>(Val, Type); 1780 write32le(Loc, (read32le(Loc) & ~0x000f0fff) | 1781 (((Val >> 16) & 0xf000) << 4) | ((Val >> 16) & 0xfff)); 1782 break; 1783 case R_ARM_THM_MOVT_ABS: 1784 case R_ARM_THM_MOVT_PREL: 1785 // Encoding T1: A = imm4:i:imm3:imm8 1786 checkInt<32>(Val, Type); 1787 write16le(Loc, 1788 0xf2c0 | // opcode 1789 ((Val >> 17) & 0x0400) | // i 1790 ((Val >> 28) & 0x000f)); // imm4 1791 write16le(Loc + 2, 1792 (read16le(Loc + 2) & 0x8f00) | // opcode 1793 ((Val >> 12) & 0x7000) | // imm3 1794 ((Val >> 16) & 0x00ff)); // imm8 1795 break; 1796 case R_ARM_THM_MOVW_ABS_NC: 1797 case R_ARM_THM_MOVW_PREL_NC: 1798 // Encoding T3: A = imm4:i:imm3:imm8 1799 write16le(Loc, 1800 0xf240 | // opcode 1801 ((Val >> 1) & 0x0400) | // i 1802 ((Val >> 12) & 0x000f)); // imm4 1803 write16le(Loc + 2, 1804 (read16le(Loc + 2) & 0x8f00) | // opcode 1805 ((Val << 4) & 0x7000) | // imm3 1806 (Val & 0x00ff)); // imm8 1807 break; 1808 default: 1809 fatal("unrecognized reloc " + Twine(Type)); 1810 } 1811 } 1812 1813 uint64_t ARMTargetInfo::getImplicitAddend(const uint8_t *Buf, 1814 uint32_t Type) const { 1815 switch (Type) { 1816 default: 1817 return 0; 1818 case R_ARM_ABS32: 1819 case R_ARM_BASE_PREL: 1820 case R_ARM_GOTOFF32: 1821 case R_ARM_GOT_BREL: 1822 case R_ARM_GOT_PREL: 1823 case R_ARM_REL32: 1824 case R_ARM_TARGET1: 1825 case R_ARM_TARGET2: 1826 case R_ARM_TLS_GD32: 1827 case R_ARM_TLS_LDM32: 1828 case R_ARM_TLS_LDO32: 1829 case R_ARM_TLS_IE32: 1830 case R_ARM_TLS_LE32: 1831 return SignExtend64<32>(read32le(Buf)); 1832 case R_ARM_PREL31: 1833 return SignExtend64<31>(read32le(Buf)); 1834 case R_ARM_CALL: 1835 case R_ARM_JUMP24: 1836 case R_ARM_PC24: 1837 case R_ARM_PLT32: 1838 return SignExtend64<26>(read32le(Buf) << 2); 1839 case R_ARM_THM_JUMP11: 1840 return SignExtend64<12>(read16le(Buf) << 1); 1841 case R_ARM_THM_JUMP19: { 1842 // Encoding T3: A = S:J2:J1:imm10:imm6:0 1843 uint16_t Hi = read16le(Buf); 1844 uint16_t Lo = read16le(Buf + 2); 1845 return SignExtend64<20>(((Hi & 0x0400) << 10) | // S 1846 ((Lo & 0x0800) << 8) | // J2 1847 ((Lo & 0x2000) << 5) | // J1 1848 ((Hi & 0x003f) << 12) | // imm6 1849 ((Lo & 0x07ff) << 1)); // imm11:0 1850 } 1851 case R_ARM_THM_CALL: 1852 case R_ARM_THM_JUMP24: { 1853 // Encoding B T4, BL T1, BLX T2: A = S:I1:I2:imm10:imm11:0 1854 // I1 = NOT(J1 EOR S), I2 = NOT(J2 EOR S) 1855 // FIXME: I1 and I2 require v6T2ops 1856 uint16_t Hi = read16le(Buf); 1857 uint16_t Lo = read16le(Buf + 2); 1858 return SignExtend64<24>(((Hi & 0x0400) << 14) | // S 1859 (~((Lo ^ (Hi << 3)) << 10) & 0x00800000) | // I1 1860 (~((Lo ^ (Hi << 1)) << 11) & 0x00400000) | // I2 1861 ((Hi & 0x003ff) << 12) | // imm0 1862 ((Lo & 0x007ff) << 1)); // imm11:0 1863 } 1864 // ELF for the ARM Architecture 4.6.1.1 the implicit addend for MOVW and 1865 // MOVT is in the range -32768 <= A < 32768 1866 case R_ARM_MOVW_ABS_NC: 1867 case R_ARM_MOVT_ABS: 1868 case R_ARM_MOVW_PREL_NC: 1869 case R_ARM_MOVT_PREL: { 1870 uint64_t Val = read32le(Buf) & 0x000f0fff; 1871 return SignExtend64<16>(((Val & 0x000f0000) >> 4) | (Val & 0x00fff)); 1872 } 1873 case R_ARM_THM_MOVW_ABS_NC: 1874 case R_ARM_THM_MOVT_ABS: 1875 case R_ARM_THM_MOVW_PREL_NC: 1876 case R_ARM_THM_MOVT_PREL: { 1877 // Encoding T3: A = imm4:i:imm3:imm8 1878 uint16_t Hi = read16le(Buf); 1879 uint16_t Lo = read16le(Buf + 2); 1880 return SignExtend64<16>(((Hi & 0x000f) << 12) | // imm4 1881 ((Hi & 0x0400) << 1) | // i 1882 ((Lo & 0x7000) >> 4) | // imm3 1883 (Lo & 0x00ff)); // imm8 1884 } 1885 } 1886 } 1887 1888 bool ARMTargetInfo::isTlsLocalDynamicRel(uint32_t Type) const { 1889 return Type == R_ARM_TLS_LDO32 || Type == R_ARM_TLS_LDM32; 1890 } 1891 1892 bool ARMTargetInfo::isTlsGlobalDynamicRel(uint32_t Type) const { 1893 return Type == R_ARM_TLS_GD32; 1894 } 1895 1896 bool ARMTargetInfo::isTlsInitialExecRel(uint32_t Type) const { 1897 return Type == R_ARM_TLS_IE32; 1898 } 1899 1900 template <class ELFT> MipsTargetInfo<ELFT>::MipsTargetInfo() { 1901 GotPltHeaderEntriesNum = 2; 1902 MaxPageSize = 65536; 1903 GotEntrySize = sizeof(typename ELFT::uint); 1904 GotPltEntrySize = sizeof(typename ELFT::uint); 1905 PltEntrySize = 16; 1906 PltHeaderSize = 32; 1907 CopyRel = R_MIPS_COPY; 1908 PltRel = R_MIPS_JUMP_SLOT; 1909 NeedsThunks = true; 1910 if (ELFT::Is64Bits) { 1911 RelativeRel = (R_MIPS_64 << 8) | R_MIPS_REL32; 1912 TlsGotRel = R_MIPS_TLS_TPREL64; 1913 TlsModuleIndexRel = R_MIPS_TLS_DTPMOD64; 1914 TlsOffsetRel = R_MIPS_TLS_DTPREL64; 1915 } else { 1916 RelativeRel = R_MIPS_REL32; 1917 TlsGotRel = R_MIPS_TLS_TPREL32; 1918 TlsModuleIndexRel = R_MIPS_TLS_DTPMOD32; 1919 TlsOffsetRel = R_MIPS_TLS_DTPREL32; 1920 } 1921 } 1922 1923 template <class ELFT> 1924 RelExpr MipsTargetInfo<ELFT>::getRelExpr(uint32_t Type, 1925 const SymbolBody &S) const { 1926 // See comment in the calculateMipsRelChain. 1927 if (ELFT::Is64Bits || Config->MipsN32Abi) 1928 Type &= 0xff; 1929 switch (Type) { 1930 default: 1931 return R_ABS; 1932 case R_MIPS_JALR: 1933 return R_HINT; 1934 case R_MIPS_GPREL16: 1935 case R_MIPS_GPREL32: 1936 return R_GOTREL; 1937 case R_MIPS_26: 1938 return R_PLT; 1939 case R_MIPS_HI16: 1940 case R_MIPS_LO16: 1941 case R_MIPS_GOT_OFST: 1942 // MIPS _gp_disp designates offset between start of function and 'gp' 1943 // pointer into GOT. __gnu_local_gp is equal to the current value of 1944 // the 'gp'. Therefore any relocations against them do not require 1945 // dynamic relocation. 1946 if (&S == ElfSym<ELFT>::MipsGpDisp) 1947 return R_PC; 1948 return R_ABS; 1949 case R_MIPS_PC32: 1950 case R_MIPS_PC16: 1951 case R_MIPS_PC19_S2: 1952 case R_MIPS_PC21_S2: 1953 case R_MIPS_PC26_S2: 1954 case R_MIPS_PCHI16: 1955 case R_MIPS_PCLO16: 1956 return R_PC; 1957 case R_MIPS_GOT16: 1958 if (S.isLocal()) 1959 return R_MIPS_GOT_LOCAL_PAGE; 1960 // fallthrough 1961 case R_MIPS_CALL16: 1962 case R_MIPS_GOT_DISP: 1963 case R_MIPS_TLS_GOTTPREL: 1964 return R_MIPS_GOT_OFF; 1965 case R_MIPS_CALL_HI16: 1966 case R_MIPS_CALL_LO16: 1967 case R_MIPS_GOT_HI16: 1968 case R_MIPS_GOT_LO16: 1969 return R_MIPS_GOT_OFF32; 1970 case R_MIPS_GOT_PAGE: 1971 return R_MIPS_GOT_LOCAL_PAGE; 1972 case R_MIPS_TLS_GD: 1973 return R_MIPS_TLSGD; 1974 case R_MIPS_TLS_LDM: 1975 return R_MIPS_TLSLD; 1976 } 1977 } 1978 1979 template <class ELFT> 1980 uint32_t MipsTargetInfo<ELFT>::getDynRel(uint32_t Type) const { 1981 if (Type == R_MIPS_32 || Type == R_MIPS_64) 1982 return RelativeRel; 1983 // Keep it going with a dummy value so that we can find more reloc errors. 1984 errorDynRel(Type); 1985 return R_MIPS_32; 1986 } 1987 1988 template <class ELFT> 1989 bool MipsTargetInfo<ELFT>::isTlsLocalDynamicRel(uint32_t Type) const { 1990 return Type == R_MIPS_TLS_LDM; 1991 } 1992 1993 template <class ELFT> 1994 bool MipsTargetInfo<ELFT>::isTlsGlobalDynamicRel(uint32_t Type) const { 1995 return Type == R_MIPS_TLS_GD; 1996 } 1997 1998 template <class ELFT> 1999 void MipsTargetInfo<ELFT>::writeGotPlt(uint8_t *Buf, const SymbolBody &) const { 2000 write32<ELFT::TargetEndianness>(Buf, Out<ELFT>::Plt->Addr); 2001 } 2002 2003 template <endianness E, uint8_t BSIZE, uint8_t SHIFT> 2004 static int64_t getPcRelocAddend(const uint8_t *Loc) { 2005 uint32_t Instr = read32<E>(Loc); 2006 uint32_t Mask = 0xffffffff >> (32 - BSIZE); 2007 return SignExtend64<BSIZE + SHIFT>((Instr & Mask) << SHIFT); 2008 } 2009 2010 template <endianness E, uint8_t BSIZE, uint8_t SHIFT> 2011 static void applyMipsPcReloc(uint8_t *Loc, uint32_t Type, uint64_t V) { 2012 uint32_t Mask = 0xffffffff >> (32 - BSIZE); 2013 uint32_t Instr = read32<E>(Loc); 2014 if (SHIFT > 0) 2015 checkAlignment<(1 << SHIFT)>(V, Type); 2016 checkInt<BSIZE + SHIFT>(V, Type); 2017 write32<E>(Loc, (Instr & ~Mask) | ((V >> SHIFT) & Mask)); 2018 } 2019 2020 template <endianness E> static void writeMipsHi16(uint8_t *Loc, uint64_t V) { 2021 uint32_t Instr = read32<E>(Loc); 2022 uint16_t Res = ((V + 0x8000) >> 16) & 0xffff; 2023 write32<E>(Loc, (Instr & 0xffff0000) | Res); 2024 } 2025 2026 template <endianness E> static void writeMipsHigher(uint8_t *Loc, uint64_t V) { 2027 uint32_t Instr = read32<E>(Loc); 2028 uint16_t Res = ((V + 0x80008000) >> 32) & 0xffff; 2029 write32<E>(Loc, (Instr & 0xffff0000) | Res); 2030 } 2031 2032 template <endianness E> static void writeMipsHighest(uint8_t *Loc, uint64_t V) { 2033 uint32_t Instr = read32<E>(Loc); 2034 uint16_t Res = ((V + 0x800080008000) >> 48) & 0xffff; 2035 write32<E>(Loc, (Instr & 0xffff0000) | Res); 2036 } 2037 2038 template <endianness E> static void writeMipsLo16(uint8_t *Loc, uint64_t V) { 2039 uint32_t Instr = read32<E>(Loc); 2040 write32<E>(Loc, (Instr & 0xffff0000) | (V & 0xffff)); 2041 } 2042 2043 template <class ELFT> static bool isMipsR6() { 2044 const auto &FirstObj = cast<ELFFileBase<ELFT>>(*Config->FirstElf); 2045 uint32_t Arch = FirstObj.getObj().getHeader()->e_flags & EF_MIPS_ARCH; 2046 return Arch == EF_MIPS_ARCH_32R6 || Arch == EF_MIPS_ARCH_64R6; 2047 } 2048 2049 template <class ELFT> 2050 void MipsTargetInfo<ELFT>::writePltHeader(uint8_t *Buf) const { 2051 const endianness E = ELFT::TargetEndianness; 2052 if (Config->MipsN32Abi) { 2053 write32<E>(Buf, 0x3c0e0000); // lui $14, %hi(&GOTPLT[0]) 2054 write32<E>(Buf + 4, 0x8dd90000); // lw $25, %lo(&GOTPLT[0])($14) 2055 write32<E>(Buf + 8, 0x25ce0000); // addiu $14, $14, %lo(&GOTPLT[0]) 2056 write32<E>(Buf + 12, 0x030ec023); // subu $24, $24, $14 2057 } else { 2058 write32<E>(Buf, 0x3c1c0000); // lui $28, %hi(&GOTPLT[0]) 2059 write32<E>(Buf + 4, 0x8f990000); // lw $25, %lo(&GOTPLT[0])($28) 2060 write32<E>(Buf + 8, 0x279c0000); // addiu $28, $28, %lo(&GOTPLT[0]) 2061 write32<E>(Buf + 12, 0x031cc023); // subu $24, $24, $28 2062 } 2063 write32<E>(Buf + 16, 0x03e07825); // move $15, $31 2064 write32<E>(Buf + 20, 0x0018c082); // srl $24, $24, 2 2065 write32<E>(Buf + 24, 0x0320f809); // jalr $25 2066 write32<E>(Buf + 28, 0x2718fffe); // subu $24, $24, 2 2067 uint64_t Got = In<ELFT>::GotPlt->getVA(); 2068 writeMipsHi16<E>(Buf, Got); 2069 writeMipsLo16<E>(Buf + 4, Got); 2070 writeMipsLo16<E>(Buf + 8, Got); 2071 } 2072 2073 template <class ELFT> 2074 void MipsTargetInfo<ELFT>::writePlt(uint8_t *Buf, uint64_t GotEntryAddr, 2075 uint64_t PltEntryAddr, int32_t Index, 2076 unsigned RelOff) const { 2077 const endianness E = ELFT::TargetEndianness; 2078 write32<E>(Buf, 0x3c0f0000); // lui $15, %hi(.got.plt entry) 2079 write32<E>(Buf + 4, 0x8df90000); // l[wd] $25, %lo(.got.plt entry)($15) 2080 // jr $25 2081 write32<E>(Buf + 8, isMipsR6<ELFT>() ? 0x03200009 : 0x03200008); 2082 write32<E>(Buf + 12, 0x25f80000); // addiu $24, $15, %lo(.got.plt entry) 2083 writeMipsHi16<E>(Buf, GotEntryAddr); 2084 writeMipsLo16<E>(Buf + 4, GotEntryAddr); 2085 writeMipsLo16<E>(Buf + 12, GotEntryAddr); 2086 } 2087 2088 template <class ELFT> 2089 RelExpr MipsTargetInfo<ELFT>::getThunkExpr(RelExpr Expr, uint32_t Type, 2090 const InputFile &File, 2091 const SymbolBody &S) const { 2092 // Any MIPS PIC code function is invoked with its address in register $t9. 2093 // So if we have a branch instruction from non-PIC code to the PIC one 2094 // we cannot make the jump directly and need to create a small stubs 2095 // to save the target function address. 2096 // See page 3-38 ftp://www.linux-mips.org/pub/linux/mips/doc/ABI/mipsabi.pdf 2097 if (Type != R_MIPS_26) 2098 return Expr; 2099 auto *F = dyn_cast<ELFFileBase<ELFT>>(&File); 2100 if (!F) 2101 return Expr; 2102 // If current file has PIC code, LA25 stub is not required. 2103 if (F->getObj().getHeader()->e_flags & EF_MIPS_PIC) 2104 return Expr; 2105 auto *D = dyn_cast<DefinedRegular<ELFT>>(&S); 2106 // LA25 is required if target file has PIC code 2107 // or target symbol is a PIC symbol. 2108 return D && D->isMipsPIC() ? R_THUNK_ABS : Expr; 2109 } 2110 2111 template <class ELFT> 2112 uint64_t MipsTargetInfo<ELFT>::getImplicitAddend(const uint8_t *Buf, 2113 uint32_t Type) const { 2114 const endianness E = ELFT::TargetEndianness; 2115 switch (Type) { 2116 default: 2117 return 0; 2118 case R_MIPS_32: 2119 case R_MIPS_GPREL32: 2120 case R_MIPS_TLS_DTPREL32: 2121 case R_MIPS_TLS_TPREL32: 2122 return read32<E>(Buf); 2123 case R_MIPS_26: 2124 // FIXME (simon): If the relocation target symbol is not a PLT entry 2125 // we should use another expression for calculation: 2126 // ((A << 2) | (P & 0xf0000000)) >> 2 2127 return SignExtend64<28>((read32<E>(Buf) & 0x3ffffff) << 2); 2128 case R_MIPS_GPREL16: 2129 case R_MIPS_LO16: 2130 case R_MIPS_PCLO16: 2131 case R_MIPS_TLS_DTPREL_HI16: 2132 case R_MIPS_TLS_DTPREL_LO16: 2133 case R_MIPS_TLS_TPREL_HI16: 2134 case R_MIPS_TLS_TPREL_LO16: 2135 return SignExtend64<16>(read32<E>(Buf)); 2136 case R_MIPS_PC16: 2137 return getPcRelocAddend<E, 16, 2>(Buf); 2138 case R_MIPS_PC19_S2: 2139 return getPcRelocAddend<E, 19, 2>(Buf); 2140 case R_MIPS_PC21_S2: 2141 return getPcRelocAddend<E, 21, 2>(Buf); 2142 case R_MIPS_PC26_S2: 2143 return getPcRelocAddend<E, 26, 2>(Buf); 2144 case R_MIPS_PC32: 2145 return getPcRelocAddend<E, 32, 0>(Buf); 2146 } 2147 } 2148 2149 static std::pair<uint32_t, uint64_t> calculateMipsRelChain(uint32_t Type, 2150 uint64_t Val) { 2151 // MIPS N64 ABI packs multiple relocations into the single relocation 2152 // record. In general, all up to three relocations can have arbitrary 2153 // types. In fact, Clang and GCC uses only a few combinations. For now, 2154 // we support two of them. That is allow to pass at least all LLVM 2155 // test suite cases. 2156 // <any relocation> / R_MIPS_SUB / R_MIPS_HI16 | R_MIPS_LO16 2157 // <any relocation> / R_MIPS_64 / R_MIPS_NONE 2158 // The first relocation is a 'real' relocation which is calculated 2159 // using the corresponding symbol's value. The second and the third 2160 // relocations used to modify result of the first one: extend it to 2161 // 64-bit, extract high or low part etc. For details, see part 2.9 Relocation 2162 // at the https://dmz-portal.mips.com/mw/images/8/82/007-4658-001.pdf 2163 uint32_t Type2 = (Type >> 8) & 0xff; 2164 uint32_t Type3 = (Type >> 16) & 0xff; 2165 if (Type2 == R_MIPS_NONE && Type3 == R_MIPS_NONE) 2166 return std::make_pair(Type, Val); 2167 if (Type2 == R_MIPS_64 && Type3 == R_MIPS_NONE) 2168 return std::make_pair(Type2, Val); 2169 if (Type2 == R_MIPS_SUB && (Type3 == R_MIPS_HI16 || Type3 == R_MIPS_LO16)) 2170 return std::make_pair(Type3, -Val); 2171 error("unsupported relocations combination " + Twine(Type)); 2172 return std::make_pair(Type & 0xff, Val); 2173 } 2174 2175 template <class ELFT> 2176 void MipsTargetInfo<ELFT>::relocateOne(uint8_t *Loc, uint32_t Type, 2177 uint64_t Val) const { 2178 const endianness E = ELFT::TargetEndianness; 2179 // Thread pointer and DRP offsets from the start of TLS data area. 2180 // https://www.linux-mips.org/wiki/NPTL 2181 if (Type == R_MIPS_TLS_DTPREL_HI16 || Type == R_MIPS_TLS_DTPREL_LO16 || 2182 Type == R_MIPS_TLS_DTPREL32 || Type == R_MIPS_TLS_DTPREL64) 2183 Val -= 0x8000; 2184 else if (Type == R_MIPS_TLS_TPREL_HI16 || Type == R_MIPS_TLS_TPREL_LO16 || 2185 Type == R_MIPS_TLS_TPREL32 || Type == R_MIPS_TLS_TPREL64) 2186 Val -= 0x7000; 2187 if (ELFT::Is64Bits || Config->MipsN32Abi) 2188 std::tie(Type, Val) = calculateMipsRelChain(Type, Val); 2189 switch (Type) { 2190 case R_MIPS_32: 2191 case R_MIPS_GPREL32: 2192 case R_MIPS_TLS_DTPREL32: 2193 case R_MIPS_TLS_TPREL32: 2194 write32<E>(Loc, Val); 2195 break; 2196 case R_MIPS_64: 2197 case R_MIPS_TLS_DTPREL64: 2198 case R_MIPS_TLS_TPREL64: 2199 write64<E>(Loc, Val); 2200 break; 2201 case R_MIPS_26: 2202 write32<E>(Loc, (read32<E>(Loc) & ~0x3ffffff) | ((Val >> 2) & 0x3ffffff)); 2203 break; 2204 case R_MIPS_GOT_DISP: 2205 case R_MIPS_GOT_PAGE: 2206 case R_MIPS_GOT16: 2207 case R_MIPS_GPREL16: 2208 case R_MIPS_TLS_GD: 2209 case R_MIPS_TLS_LDM: 2210 checkInt<16>(Val, Type); 2211 // fallthrough 2212 case R_MIPS_CALL16: 2213 case R_MIPS_CALL_LO16: 2214 case R_MIPS_GOT_LO16: 2215 case R_MIPS_GOT_OFST: 2216 case R_MIPS_LO16: 2217 case R_MIPS_PCLO16: 2218 case R_MIPS_TLS_DTPREL_LO16: 2219 case R_MIPS_TLS_GOTTPREL: 2220 case R_MIPS_TLS_TPREL_LO16: 2221 writeMipsLo16<E>(Loc, Val); 2222 break; 2223 case R_MIPS_CALL_HI16: 2224 case R_MIPS_GOT_HI16: 2225 case R_MIPS_HI16: 2226 case R_MIPS_PCHI16: 2227 case R_MIPS_TLS_DTPREL_HI16: 2228 case R_MIPS_TLS_TPREL_HI16: 2229 writeMipsHi16<E>(Loc, Val); 2230 break; 2231 case R_MIPS_HIGHER: 2232 writeMipsHigher<E>(Loc, Val); 2233 break; 2234 case R_MIPS_HIGHEST: 2235 writeMipsHighest<E>(Loc, Val); 2236 break; 2237 case R_MIPS_JALR: 2238 // Ignore this optimization relocation for now 2239 break; 2240 case R_MIPS_PC16: 2241 applyMipsPcReloc<E, 16, 2>(Loc, Type, Val); 2242 break; 2243 case R_MIPS_PC19_S2: 2244 applyMipsPcReloc<E, 19, 2>(Loc, Type, Val); 2245 break; 2246 case R_MIPS_PC21_S2: 2247 applyMipsPcReloc<E, 21, 2>(Loc, Type, Val); 2248 break; 2249 case R_MIPS_PC26_S2: 2250 applyMipsPcReloc<E, 26, 2>(Loc, Type, Val); 2251 break; 2252 case R_MIPS_PC32: 2253 applyMipsPcReloc<E, 32, 0>(Loc, Type, Val); 2254 break; 2255 default: 2256 fatal("unrecognized reloc " + Twine(Type)); 2257 } 2258 } 2259 2260 template <class ELFT> 2261 bool MipsTargetInfo<ELFT>::usesOnlyLowPageBits(uint32_t Type) const { 2262 return Type == R_MIPS_LO16 || Type == R_MIPS_GOT_OFST; 2263 } 2264 } 2265 } 2266