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 "Thunks.h" 33 34 #include "llvm/ADT/ArrayRef.h" 35 #include "llvm/Object/ELF.h" 36 #include "llvm/Support/Endian.h" 37 #include "llvm/Support/ELF.h" 38 39 using namespace llvm; 40 using namespace llvm::object; 41 using namespace llvm::support::endian; 42 using namespace llvm::ELF; 43 44 namespace lld { 45 namespace elf { 46 47 TargetInfo *Target; 48 49 static void or32le(uint8_t *P, int32_t V) { write32le(P, read32le(P) | V); } 50 51 StringRef getRelName(uint32_t Type) { 52 return getELFRelocationTypeName(Config->EMachine, Type); 53 } 54 55 template <unsigned N> static void checkInt(int64_t V, uint32_t Type) { 56 if (!isInt<N>(V)) 57 error("relocation " + getRelName(Type) + " out of range"); 58 } 59 60 template <unsigned N> static void checkUInt(uint64_t V, uint32_t Type) { 61 if (!isUInt<N>(V)) 62 error("relocation " + getRelName(Type) + " out of range"); 63 } 64 65 template <unsigned N> static void checkIntUInt(uint64_t V, uint32_t Type) { 66 if (!isInt<N>(V) && !isUInt<N>(V)) 67 error("relocation " + getRelName(Type) + " out of range"); 68 } 69 70 template <unsigned N> static void checkAlignment(uint64_t V, uint32_t Type) { 71 if ((V & (N - 1)) != 0) 72 error("improper alignment for relocation " + getRelName(Type)); 73 } 74 75 static void errorDynRel(uint32_t Type) { 76 error("relocation " + getRelName(Type) + 77 " cannot be used against shared object; recompile with -fPIC."); 78 } 79 80 namespace { 81 class X86TargetInfo final : public TargetInfo { 82 public: 83 X86TargetInfo(); 84 RelExpr getRelExpr(uint32_t Type, const SymbolBody &S) const override; 85 uint64_t getImplicitAddend(const uint8_t *Buf, uint32_t Type) const override; 86 void writeGotPltHeader(uint8_t *Buf) const override; 87 uint32_t getDynRel(uint32_t Type) const override; 88 bool isTlsLocalDynamicRel(uint32_t Type) const override; 89 bool isTlsGlobalDynamicRel(uint32_t Type) const override; 90 bool isTlsInitialExecRel(uint32_t Type) const override; 91 void writeGotPlt(uint8_t *Buf, const SymbolBody &S) const override; 92 void writePltHeader(uint8_t *Buf) const override; 93 void writePlt(uint8_t *Buf, uint64_t GotEntryAddr, uint64_t PltEntryAddr, 94 int32_t Index, unsigned RelOff) const override; 95 void relocateOne(uint8_t *Loc, uint32_t Type, uint64_t Val) const override; 96 97 RelExpr adjustRelaxExpr(uint32_t Type, const uint8_t *Data, 98 RelExpr Expr) const override; 99 void relaxTlsGdToIe(uint8_t *Loc, uint32_t Type, uint64_t Val) const override; 100 void relaxTlsGdToLe(uint8_t *Loc, uint32_t Type, uint64_t Val) const override; 101 void relaxTlsIeToLe(uint8_t *Loc, uint32_t Type, uint64_t Val) const override; 102 void relaxTlsLdToLe(uint8_t *Loc, uint32_t Type, uint64_t Val) const override; 103 }; 104 105 template <class ELFT> class X86_64TargetInfo final : public TargetInfo { 106 public: 107 X86_64TargetInfo(); 108 RelExpr getRelExpr(uint32_t Type, const SymbolBody &S) const override; 109 uint32_t getDynRel(uint32_t Type) const override; 110 bool isTlsLocalDynamicRel(uint32_t Type) const override; 111 bool isTlsGlobalDynamicRel(uint32_t Type) const override; 112 bool isTlsInitialExecRel(uint32_t Type) const override; 113 void writeGotPltHeader(uint8_t *Buf) const override; 114 void writeGotPlt(uint8_t *Buf, const SymbolBody &S) const override; 115 void writePltHeader(uint8_t *Buf) const override; 116 void writePlt(uint8_t *Buf, uint64_t GotEntryAddr, uint64_t PltEntryAddr, 117 int32_t Index, unsigned RelOff) const override; 118 void relocateOne(uint8_t *Loc, uint32_t Type, uint64_t Val) const override; 119 120 RelExpr adjustRelaxExpr(uint32_t Type, const uint8_t *Data, 121 RelExpr Expr) const override; 122 void relaxGot(uint8_t *Loc, uint64_t Val) const override; 123 void relaxTlsGdToIe(uint8_t *Loc, uint32_t Type, uint64_t Val) const override; 124 void relaxTlsGdToLe(uint8_t *Loc, uint32_t Type, uint64_t Val) const override; 125 void relaxTlsIeToLe(uint8_t *Loc, uint32_t Type, uint64_t Val) const override; 126 void relaxTlsLdToLe(uint8_t *Loc, uint32_t Type, uint64_t Val) const override; 127 128 private: 129 void relaxGotNoPic(uint8_t *Loc, uint64_t Val, uint8_t Op, 130 uint8_t ModRm) const; 131 }; 132 133 class PPCTargetInfo final : public TargetInfo { 134 public: 135 PPCTargetInfo(); 136 void relocateOne(uint8_t *Loc, uint32_t Type, uint64_t Val) const override; 137 RelExpr getRelExpr(uint32_t Type, const SymbolBody &S) const override; 138 }; 139 140 class PPC64TargetInfo final : public TargetInfo { 141 public: 142 PPC64TargetInfo(); 143 RelExpr getRelExpr(uint32_t Type, const SymbolBody &S) const override; 144 void writePlt(uint8_t *Buf, uint64_t GotEntryAddr, uint64_t PltEntryAddr, 145 int32_t Index, unsigned RelOff) const override; 146 void relocateOne(uint8_t *Loc, uint32_t Type, uint64_t Val) const override; 147 }; 148 149 class AArch64TargetInfo final : public TargetInfo { 150 public: 151 AArch64TargetInfo(); 152 RelExpr getRelExpr(uint32_t Type, const SymbolBody &S) const override; 153 uint32_t getDynRel(uint32_t Type) const override; 154 bool isTlsInitialExecRel(uint32_t Type) const override; 155 void writeGotPlt(uint8_t *Buf, const SymbolBody &S) const override; 156 void writePltHeader(uint8_t *Buf) const override; 157 void writePlt(uint8_t *Buf, uint64_t GotEntryAddr, uint64_t PltEntryAddr, 158 int32_t Index, unsigned RelOff) const override; 159 bool usesOnlyLowPageBits(uint32_t Type) const override; 160 void relocateOne(uint8_t *Loc, uint32_t Type, uint64_t Val) const override; 161 RelExpr adjustRelaxExpr(uint32_t Type, const uint8_t *Data, 162 RelExpr Expr) const override; 163 void relaxTlsGdToLe(uint8_t *Loc, uint32_t Type, uint64_t Val) const override; 164 void relaxTlsGdToIe(uint8_t *Loc, uint32_t Type, uint64_t Val) const override; 165 void relaxTlsIeToLe(uint8_t *Loc, uint32_t Type, uint64_t Val) const override; 166 }; 167 168 class AMDGPUTargetInfo final : public TargetInfo { 169 public: 170 AMDGPUTargetInfo(); 171 void relocateOne(uint8_t *Loc, uint32_t Type, uint64_t Val) const override; 172 RelExpr getRelExpr(uint32_t Type, const SymbolBody &S) const override; 173 }; 174 175 class ARMTargetInfo final : public TargetInfo { 176 public: 177 ARMTargetInfo(); 178 RelExpr getRelExpr(uint32_t Type, const SymbolBody &S) const override; 179 uint32_t getDynRel(uint32_t Type) const override; 180 uint64_t getImplicitAddend(const uint8_t *Buf, uint32_t Type) const override; 181 bool isTlsLocalDynamicRel(uint32_t Type) const override; 182 bool isTlsGlobalDynamicRel(uint32_t Type) const override; 183 bool isTlsInitialExecRel(uint32_t Type) const override; 184 void writeGotPlt(uint8_t *Buf, const SymbolBody &S) const override; 185 void writePltHeader(uint8_t *Buf) const override; 186 void writePlt(uint8_t *Buf, uint64_t GotEntryAddr, uint64_t PltEntryAddr, 187 int32_t Index, unsigned RelOff) const override; 188 RelExpr getThunkExpr(RelExpr Expr, uint32_t RelocType, 189 const InputFile &File, 190 const SymbolBody &S) const override; 191 void relocateOne(uint8_t *Loc, uint32_t Type, uint64_t Val) const override; 192 }; 193 194 template <class ELFT> class MipsTargetInfo final : public TargetInfo { 195 public: 196 MipsTargetInfo(); 197 RelExpr getRelExpr(uint32_t Type, const SymbolBody &S) const override; 198 uint64_t getImplicitAddend(const uint8_t *Buf, uint32_t Type) const override; 199 uint32_t getDynRel(uint32_t Type) const override; 200 bool isTlsLocalDynamicRel(uint32_t Type) const override; 201 bool isTlsGlobalDynamicRel(uint32_t Type) const override; 202 void writeGotPlt(uint8_t *Buf, const SymbolBody &S) const override; 203 void writePltHeader(uint8_t *Buf) const override; 204 void writePlt(uint8_t *Buf, uint64_t GotEntryAddr, uint64_t PltEntryAddr, 205 int32_t Index, unsigned RelOff) const override; 206 RelExpr getThunkExpr(RelExpr Expr, uint32_t RelocType, 207 const InputFile &File, 208 const SymbolBody &S) const override; 209 void relocateOne(uint8_t *Loc, uint32_t Type, uint64_t Val) const override; 210 bool usesOnlyLowPageBits(uint32_t Type) const override; 211 }; 212 } // anonymous namespace 213 214 TargetInfo *createTarget() { 215 switch (Config->EMachine) { 216 case EM_386: 217 case EM_IAMCU: 218 return new X86TargetInfo(); 219 case EM_AARCH64: 220 return new AArch64TargetInfo(); 221 case EM_AMDGPU: 222 return new AMDGPUTargetInfo(); 223 case EM_ARM: 224 return new ARMTargetInfo(); 225 case EM_MIPS: 226 switch (Config->EKind) { 227 case ELF32LEKind: 228 return new MipsTargetInfo<ELF32LE>(); 229 case ELF32BEKind: 230 return new MipsTargetInfo<ELF32BE>(); 231 case ELF64LEKind: 232 return new MipsTargetInfo<ELF64LE>(); 233 case ELF64BEKind: 234 return new MipsTargetInfo<ELF64BE>(); 235 default: 236 fatal("unsupported MIPS target"); 237 } 238 case EM_PPC: 239 return new PPCTargetInfo(); 240 case EM_PPC64: 241 return new PPC64TargetInfo(); 242 case EM_X86_64: 243 if (Config->EKind == ELF32LEKind) 244 return new X86_64TargetInfo<ELF32LE>(); 245 return new X86_64TargetInfo<ELF64LE>(); 246 } 247 fatal("unknown target machine"); 248 } 249 250 TargetInfo::~TargetInfo() {} 251 252 uint64_t TargetInfo::getImplicitAddend(const uint8_t *Buf, 253 uint32_t Type) const { 254 return 0; 255 } 256 257 bool TargetInfo::usesOnlyLowPageBits(uint32_t Type) const { return false; } 258 259 RelExpr TargetInfo::getThunkExpr(RelExpr Expr, uint32_t RelocType, 260 const InputFile &File, 261 const SymbolBody &S) const { 262 return Expr; 263 } 264 265 bool TargetInfo::isTlsInitialExecRel(uint32_t Type) const { return false; } 266 267 bool TargetInfo::isTlsLocalDynamicRel(uint32_t Type) const { return false; } 268 269 bool TargetInfo::isTlsGlobalDynamicRel(uint32_t Type) const { 270 return false; 271 } 272 273 RelExpr TargetInfo::adjustRelaxExpr(uint32_t Type, const uint8_t *Data, 274 RelExpr Expr) const { 275 return Expr; 276 } 277 278 void TargetInfo::relaxGot(uint8_t *Loc, uint64_t Val) const { 279 llvm_unreachable("Should not have claimed to be relaxable"); 280 } 281 282 void TargetInfo::relaxTlsGdToLe(uint8_t *Loc, uint32_t Type, 283 uint64_t Val) const { 284 llvm_unreachable("Should not have claimed to be relaxable"); 285 } 286 287 void TargetInfo::relaxTlsGdToIe(uint8_t *Loc, uint32_t Type, 288 uint64_t Val) const { 289 llvm_unreachable("Should not have claimed to be relaxable"); 290 } 291 292 void TargetInfo::relaxTlsIeToLe(uint8_t *Loc, uint32_t Type, 293 uint64_t Val) const { 294 llvm_unreachable("Should not have claimed to be relaxable"); 295 } 296 297 void TargetInfo::relaxTlsLdToLe(uint8_t *Loc, uint32_t Type, 298 uint64_t Val) const { 299 llvm_unreachable("Should not have claimed to be relaxable"); 300 } 301 302 X86TargetInfo::X86TargetInfo() { 303 CopyRel = R_386_COPY; 304 GotRel = R_386_GLOB_DAT; 305 PltRel = R_386_JUMP_SLOT; 306 IRelativeRel = R_386_IRELATIVE; 307 RelativeRel = R_386_RELATIVE; 308 TlsGotRel = R_386_TLS_TPOFF; 309 TlsModuleIndexRel = R_386_TLS_DTPMOD32; 310 TlsOffsetRel = R_386_TLS_DTPOFF32; 311 GotEntrySize = 4; 312 GotPltEntrySize = 4; 313 PltEntrySize = 16; 314 PltHeaderSize = 16; 315 TlsGdRelaxSkip = 2; 316 } 317 318 RelExpr X86TargetInfo::getRelExpr(uint32_t Type, const SymbolBody &S) const { 319 switch (Type) { 320 default: 321 return R_ABS; 322 case R_386_TLS_GD: 323 return R_TLSGD; 324 case R_386_TLS_LDM: 325 return R_TLSLD; 326 case R_386_PLT32: 327 return R_PLT_PC; 328 case R_386_PC32: 329 return R_PC; 330 case R_386_GOTPC: 331 return R_GOTONLY_PC_FROM_END; 332 case R_386_TLS_IE: 333 return R_GOT; 334 case R_386_GOT32: 335 case R_386_GOT32X: 336 case R_386_TLS_GOTIE: 337 return R_GOT_FROM_END; 338 case R_386_GOTOFF: 339 return R_GOTREL_FROM_END; 340 case R_386_TLS_LE: 341 return R_TLS; 342 case R_386_TLS_LE_32: 343 return R_NEG_TLS; 344 } 345 } 346 347 RelExpr X86TargetInfo::adjustRelaxExpr(uint32_t Type, const uint8_t *Data, 348 RelExpr Expr) const { 349 switch (Expr) { 350 default: 351 return Expr; 352 case R_RELAX_TLS_GD_TO_IE: 353 return R_RELAX_TLS_GD_TO_IE_END; 354 case R_RELAX_TLS_GD_TO_LE: 355 return R_RELAX_TLS_GD_TO_LE_NEG; 356 } 357 } 358 359 void X86TargetInfo::writeGotPltHeader(uint8_t *Buf) const { 360 write32le(Buf, Out<ELF32LE>::Dynamic->getVA()); 361 } 362 363 void X86TargetInfo::writeGotPlt(uint8_t *Buf, const SymbolBody &S) const { 364 // Entries in .got.plt initially points back to the corresponding 365 // PLT entries with a fixed offset to skip the first instruction. 366 write32le(Buf, S.getPltVA<ELF32LE>() + 6); 367 } 368 369 uint32_t X86TargetInfo::getDynRel(uint32_t Type) const { 370 if (Type == R_386_TLS_LE) 371 return R_386_TLS_TPOFF; 372 if (Type == R_386_TLS_LE_32) 373 return R_386_TLS_TPOFF32; 374 return Type; 375 } 376 377 bool X86TargetInfo::isTlsGlobalDynamicRel(uint32_t Type) const { 378 return Type == R_386_TLS_GD; 379 } 380 381 bool X86TargetInfo::isTlsLocalDynamicRel(uint32_t Type) const { 382 return Type == R_386_TLS_LDO_32 || Type == R_386_TLS_LDM; 383 } 384 385 bool X86TargetInfo::isTlsInitialExecRel(uint32_t Type) const { 386 return Type == R_386_TLS_IE || Type == R_386_TLS_GOTIE; 387 } 388 389 void X86TargetInfo::writePltHeader(uint8_t *Buf) const { 390 // Executable files and shared object files have 391 // separate procedure linkage tables. 392 if (Config->Pic) { 393 const uint8_t V[] = { 394 0xff, 0xb3, 0x04, 0x00, 0x00, 0x00, // pushl 4(%ebx) 395 0xff, 0xa3, 0x08, 0x00, 0x00, 0x00, // jmp *8(%ebx) 396 0x90, 0x90, 0x90, 0x90 // nop; nop; nop; nop 397 }; 398 memcpy(Buf, V, sizeof(V)); 399 return; 400 } 401 402 const uint8_t PltData[] = { 403 0xff, 0x35, 0x00, 0x00, 0x00, 0x00, // pushl (GOT+4) 404 0xff, 0x25, 0x00, 0x00, 0x00, 0x00, // jmp *(GOT+8) 405 0x90, 0x90, 0x90, 0x90 // nop; nop; nop; nop 406 }; 407 memcpy(Buf, PltData, sizeof(PltData)); 408 uint32_t Got = Out<ELF32LE>::GotPlt->getVA(); 409 write32le(Buf + 2, Got + 4); 410 write32le(Buf + 8, Got + 8); 411 } 412 413 void X86TargetInfo::writePlt(uint8_t *Buf, uint64_t GotEntryAddr, 414 uint64_t PltEntryAddr, int32_t Index, 415 unsigned RelOff) const { 416 const uint8_t Inst[] = { 417 0xff, 0x00, 0x00, 0x00, 0x00, 0x00, // jmp *foo_in_GOT|*foo@GOT(%ebx) 418 0x68, 0x00, 0x00, 0x00, 0x00, // pushl $reloc_offset 419 0xe9, 0x00, 0x00, 0x00, 0x00 // jmp .PLT0@PC 420 }; 421 memcpy(Buf, Inst, sizeof(Inst)); 422 423 // jmp *foo@GOT(%ebx) or jmp *foo_in_GOT 424 Buf[1] = Config->Pic ? 0xa3 : 0x25; 425 uint32_t Got = Out<ELF32LE>::GotPlt->getVA(); 426 write32le(Buf + 2, Config->Shared ? GotEntryAddr - Got : GotEntryAddr); 427 write32le(Buf + 7, RelOff); 428 write32le(Buf + 12, -Index * PltEntrySize - PltHeaderSize - 16); 429 } 430 431 uint64_t X86TargetInfo::getImplicitAddend(const uint8_t *Buf, 432 uint32_t Type) const { 433 switch (Type) { 434 default: 435 return 0; 436 case R_386_32: 437 case R_386_GOT32: 438 case R_386_GOT32X: 439 case R_386_GOTOFF: 440 case R_386_GOTPC: 441 case R_386_PC32: 442 case R_386_PLT32: 443 case R_386_TLS_LE: 444 return read32le(Buf); 445 } 446 } 447 448 void X86TargetInfo::relocateOne(uint8_t *Loc, uint32_t Type, 449 uint64_t Val) const { 450 checkInt<32>(Val, Type); 451 write32le(Loc, Val); 452 } 453 454 void X86TargetInfo::relaxTlsGdToLe(uint8_t *Loc, uint32_t Type, 455 uint64_t Val) const { 456 // Convert 457 // leal x@tlsgd(, %ebx, 1), 458 // call __tls_get_addr@plt 459 // to 460 // movl %gs:0,%eax 461 // subl $x@ntpoff,%eax 462 const uint8_t Inst[] = { 463 0x65, 0xa1, 0x00, 0x00, 0x00, 0x00, // movl %gs:0, %eax 464 0x81, 0xe8, 0x00, 0x00, 0x00, 0x00 // subl 0(%ebx), %eax 465 }; 466 memcpy(Loc - 3, Inst, sizeof(Inst)); 467 relocateOne(Loc + 5, R_386_32, Val); 468 } 469 470 void X86TargetInfo::relaxTlsGdToIe(uint8_t *Loc, uint32_t Type, 471 uint64_t Val) const { 472 // Convert 473 // leal x@tlsgd(, %ebx, 1), 474 // call __tls_get_addr@plt 475 // to 476 // movl %gs:0, %eax 477 // addl x@gotntpoff(%ebx), %eax 478 const uint8_t Inst[] = { 479 0x65, 0xa1, 0x00, 0x00, 0x00, 0x00, // movl %gs:0, %eax 480 0x03, 0x83, 0x00, 0x00, 0x00, 0x00 // addl 0(%ebx), %eax 481 }; 482 memcpy(Loc - 3, Inst, sizeof(Inst)); 483 relocateOne(Loc + 5, R_386_32, Val); 484 } 485 486 // In some conditions, relocations can be optimized to avoid using GOT. 487 // This function does that for Initial Exec to Local Exec case. 488 void X86TargetInfo::relaxTlsIeToLe(uint8_t *Loc, uint32_t Type, 489 uint64_t Val) const { 490 // Ulrich's document section 6.2 says that @gotntpoff can 491 // be used with MOVL or ADDL instructions. 492 // @indntpoff is similar to @gotntpoff, but for use in 493 // position dependent code. 494 uint8_t Reg = (Loc[-1] >> 3) & 7; 495 496 if (Type == R_386_TLS_IE) { 497 if (Loc[-1] == 0xa1) { 498 // "movl foo@indntpoff,%eax" -> "movl $foo,%eax" 499 // This case is different from the generic case below because 500 // this is a 5 byte instruction while below is 6 bytes. 501 Loc[-1] = 0xb8; 502 } else if (Loc[-2] == 0x8b) { 503 // "movl foo@indntpoff,%reg" -> "movl $foo,%reg" 504 Loc[-2] = 0xc7; 505 Loc[-1] = 0xc0 | Reg; 506 } else { 507 // "addl foo@indntpoff,%reg" -> "addl $foo,%reg" 508 Loc[-2] = 0x81; 509 Loc[-1] = 0xc0 | Reg; 510 } 511 } else { 512 assert(Type == R_386_TLS_GOTIE); 513 if (Loc[-2] == 0x8b) { 514 // "movl foo@gottpoff(%rip),%reg" -> "movl $foo,%reg" 515 Loc[-2] = 0xc7; 516 Loc[-1] = 0xc0 | Reg; 517 } else { 518 // "addl foo@gotntpoff(%rip),%reg" -> "leal foo(%reg),%reg" 519 Loc[-2] = 0x8d; 520 Loc[-1] = 0x80 | (Reg << 3) | Reg; 521 } 522 } 523 relocateOne(Loc, R_386_TLS_LE, Val); 524 } 525 526 void X86TargetInfo::relaxTlsLdToLe(uint8_t *Loc, uint32_t Type, 527 uint64_t Val) const { 528 if (Type == R_386_TLS_LDO_32) { 529 relocateOne(Loc, R_386_TLS_LE, Val); 530 return; 531 } 532 533 // Convert 534 // leal foo(%reg),%eax 535 // call ___tls_get_addr 536 // to 537 // movl %gs:0,%eax 538 // nop 539 // leal 0(%esi,1),%esi 540 const uint8_t Inst[] = { 541 0x65, 0xa1, 0x00, 0x00, 0x00, 0x00, // movl %gs:0,%eax 542 0x90, // nop 543 0x8d, 0x74, 0x26, 0x00 // leal 0(%esi,1),%esi 544 }; 545 memcpy(Loc - 2, Inst, sizeof(Inst)); 546 } 547 548 template <class ELFT> X86_64TargetInfo<ELFT>::X86_64TargetInfo() { 549 MaxPageSize = 0x200000; // 2MiB 550 CopyRel = R_X86_64_COPY; 551 GotRel = R_X86_64_GLOB_DAT; 552 PltRel = R_X86_64_JUMP_SLOT; 553 RelativeRel = R_X86_64_RELATIVE; 554 IRelativeRel = R_X86_64_IRELATIVE; 555 TlsGotRel = R_X86_64_TPOFF64; 556 TlsModuleIndexRel = R_X86_64_DTPMOD64; 557 TlsOffsetRel = R_X86_64_DTPOFF64; 558 GotEntrySize = 8; 559 GotPltEntrySize = 8; 560 PltEntrySize = 16; 561 PltHeaderSize = 16; 562 TlsGdRelaxSkip = 2; 563 } 564 565 template <class ELFT> 566 RelExpr X86_64TargetInfo<ELFT>::getRelExpr(uint32_t Type, 567 const SymbolBody &S) const { 568 switch (Type) { 569 default: 570 return R_ABS; 571 case R_X86_64_TPOFF32: 572 return R_TLS; 573 case R_X86_64_TLSLD: 574 return R_TLSLD_PC; 575 case R_X86_64_TLSGD: 576 return R_TLSGD_PC; 577 case R_X86_64_SIZE32: 578 case R_X86_64_SIZE64: 579 return R_SIZE; 580 case R_X86_64_PLT32: 581 return R_PLT_PC; 582 case R_X86_64_PC32: 583 case R_X86_64_PC64: 584 return R_PC; 585 case R_X86_64_GOT32: 586 return R_GOT_FROM_END; 587 case R_X86_64_GOTPCREL: 588 case R_X86_64_GOTPCRELX: 589 case R_X86_64_REX_GOTPCRELX: 590 case R_X86_64_GOTTPOFF: 591 return R_GOT_PC; 592 } 593 } 594 595 template <class ELFT> 596 void X86_64TargetInfo<ELFT>::writeGotPltHeader(uint8_t *Buf) const { 597 // The first entry holds the value of _DYNAMIC. It is not clear why that is 598 // required, but it is documented in the psabi and the glibc dynamic linker 599 // seems to use it (note that this is relevant for linking ld.so, not any 600 // other program). 601 write64le(Buf, Out<ELFT>::Dynamic->getVA()); 602 } 603 604 template <class ELFT> 605 void X86_64TargetInfo<ELFT>::writeGotPlt(uint8_t *Buf, 606 const SymbolBody &S) const { 607 // See comments in X86TargetInfo::writeGotPlt. 608 write32le(Buf, S.getPltVA<ELFT>() + 6); 609 } 610 611 template <class ELFT> 612 void X86_64TargetInfo<ELFT>::writePltHeader(uint8_t *Buf) const { 613 const uint8_t PltData[] = { 614 0xff, 0x35, 0x00, 0x00, 0x00, 0x00, // pushq GOT+8(%rip) 615 0xff, 0x25, 0x00, 0x00, 0x00, 0x00, // jmp *GOT+16(%rip) 616 0x0f, 0x1f, 0x40, 0x00 // nopl 0x0(rax) 617 }; 618 memcpy(Buf, PltData, sizeof(PltData)); 619 uint64_t Got = Out<ELFT>::GotPlt->getVA(); 620 uint64_t Plt = Out<ELFT>::Plt->getVA(); 621 write32le(Buf + 2, Got - Plt + 2); // GOT+8 622 write32le(Buf + 8, Got - Plt + 4); // GOT+16 623 } 624 625 template <class ELFT> 626 void X86_64TargetInfo<ELFT>::writePlt(uint8_t *Buf, uint64_t GotEntryAddr, 627 uint64_t PltEntryAddr, int32_t Index, 628 unsigned RelOff) const { 629 const uint8_t Inst[] = { 630 0xff, 0x25, 0x00, 0x00, 0x00, 0x00, // jmpq *got(%rip) 631 0x68, 0x00, 0x00, 0x00, 0x00, // pushq <relocation index> 632 0xe9, 0x00, 0x00, 0x00, 0x00 // jmpq plt[0] 633 }; 634 memcpy(Buf, Inst, sizeof(Inst)); 635 636 write32le(Buf + 2, GotEntryAddr - PltEntryAddr - 6); 637 write32le(Buf + 7, Index); 638 write32le(Buf + 12, -Index * PltEntrySize - PltHeaderSize - 16); 639 } 640 641 template <class ELFT> 642 uint32_t X86_64TargetInfo<ELFT>::getDynRel(uint32_t Type) const { 643 if (Type == R_X86_64_PC32 || Type == R_X86_64_32) 644 errorDynRel(Type); 645 return Type; 646 } 647 648 template <class ELFT> 649 bool X86_64TargetInfo<ELFT>::isTlsInitialExecRel(uint32_t Type) const { 650 return Type == R_X86_64_GOTTPOFF; 651 } 652 653 template <class ELFT> 654 bool X86_64TargetInfo<ELFT>::isTlsGlobalDynamicRel(uint32_t Type) const { 655 return Type == R_X86_64_TLSGD; 656 } 657 658 template <class ELFT> 659 bool X86_64TargetInfo<ELFT>::isTlsLocalDynamicRel(uint32_t Type) const { 660 return Type == R_X86_64_DTPOFF32 || Type == R_X86_64_DTPOFF64 || 661 Type == R_X86_64_TLSLD; 662 } 663 664 template <class ELFT> 665 void X86_64TargetInfo<ELFT>::relaxTlsGdToLe(uint8_t *Loc, uint32_t Type, 666 uint64_t Val) const { 667 // Convert 668 // .byte 0x66 669 // leaq x@tlsgd(%rip), %rdi 670 // .word 0x6666 671 // rex64 672 // call __tls_get_addr@plt 673 // to 674 // mov %fs:0x0,%rax 675 // lea x@tpoff,%rax 676 const uint8_t Inst[] = { 677 0x64, 0x48, 0x8b, 0x04, 0x25, 0x00, 0x00, 0x00, 0x00, // mov %fs:0x0,%rax 678 0x48, 0x8d, 0x80, 0x00, 0x00, 0x00, 0x00 // lea x@tpoff,%rax 679 }; 680 memcpy(Loc - 4, Inst, sizeof(Inst)); 681 // The original code used a pc relative relocation and so we have to 682 // compensate for the -4 in had in the addend. 683 relocateOne(Loc + 8, R_X86_64_TPOFF32, Val + 4); 684 } 685 686 template <class ELFT> 687 void X86_64TargetInfo<ELFT>::relaxTlsGdToIe(uint8_t *Loc, uint32_t Type, 688 uint64_t Val) const { 689 // Convert 690 // .byte 0x66 691 // leaq x@tlsgd(%rip), %rdi 692 // .word 0x6666 693 // rex64 694 // call __tls_get_addr@plt 695 // to 696 // mov %fs:0x0,%rax 697 // addq x@tpoff,%rax 698 const uint8_t Inst[] = { 699 0x64, 0x48, 0x8b, 0x04, 0x25, 0x00, 0x00, 0x00, 0x00, // mov %fs:0x0,%rax 700 0x48, 0x03, 0x05, 0x00, 0x00, 0x00, 0x00 // addq x@tpoff,%rax 701 }; 702 memcpy(Loc - 4, Inst, sizeof(Inst)); 703 // Both code sequences are PC relatives, but since we are moving the constant 704 // forward by 8 bytes we have to subtract the value by 8. 705 relocateOne(Loc + 8, R_X86_64_PC32, Val - 8); 706 } 707 708 // In some conditions, R_X86_64_GOTTPOFF relocation can be optimized to 709 // R_X86_64_TPOFF32 so that it does not use GOT. 710 template <class ELFT> 711 void X86_64TargetInfo<ELFT>::relaxTlsIeToLe(uint8_t *Loc, uint32_t Type, 712 uint64_t Val) const { 713 uint8_t *Inst = Loc - 3; 714 uint8_t Reg = Loc[-1] >> 3; 715 uint8_t *RegSlot = Loc - 1; 716 717 // Note that ADD with RSP or R12 is converted to ADD instead of LEA 718 // because LEA with these registers needs 4 bytes to encode and thus 719 // wouldn't fit the space. 720 721 if (memcmp(Inst, "\x48\x03\x25", 3) == 0) { 722 // "addq foo@gottpoff(%rip),%rsp" -> "addq $foo,%rsp" 723 memcpy(Inst, "\x48\x81\xc4", 3); 724 } else if (memcmp(Inst, "\x4c\x03\x25", 3) == 0) { 725 // "addq foo@gottpoff(%rip),%r12" -> "addq $foo,%r12" 726 memcpy(Inst, "\x49\x81\xc4", 3); 727 } else if (memcmp(Inst, "\x4c\x03", 2) == 0) { 728 // "addq foo@gottpoff(%rip),%r[8-15]" -> "leaq foo(%r[8-15]),%r[8-15]" 729 memcpy(Inst, "\x4d\x8d", 2); 730 *RegSlot = 0x80 | (Reg << 3) | Reg; 731 } else if (memcmp(Inst, "\x48\x03", 2) == 0) { 732 // "addq foo@gottpoff(%rip),%reg -> "leaq foo(%reg),%reg" 733 memcpy(Inst, "\x48\x8d", 2); 734 *RegSlot = 0x80 | (Reg << 3) | Reg; 735 } else if (memcmp(Inst, "\x4c\x8b", 2) == 0) { 736 // "movq foo@gottpoff(%rip),%r[8-15]" -> "movq $foo,%r[8-15]" 737 memcpy(Inst, "\x49\xc7", 2); 738 *RegSlot = 0xc0 | Reg; 739 } else if (memcmp(Inst, "\x48\x8b", 2) == 0) { 740 // "movq foo@gottpoff(%rip),%reg" -> "movq $foo,%reg" 741 memcpy(Inst, "\x48\xc7", 2); 742 *RegSlot = 0xc0 | Reg; 743 } else { 744 fatal("R_X86_64_GOTTPOFF must be used in MOVQ or ADDQ instructions only"); 745 } 746 747 // The original code used a PC relative relocation. 748 // Need to compensate for the -4 it had in the addend. 749 relocateOne(Loc, R_X86_64_TPOFF32, Val + 4); 750 } 751 752 template <class ELFT> 753 void X86_64TargetInfo<ELFT>::relaxTlsLdToLe(uint8_t *Loc, uint32_t Type, 754 uint64_t Val) const { 755 // Convert 756 // leaq bar@tlsld(%rip), %rdi 757 // callq __tls_get_addr@PLT 758 // leaq bar@dtpoff(%rax), %rcx 759 // to 760 // .word 0x6666 761 // .byte 0x66 762 // mov %fs:0,%rax 763 // leaq bar@tpoff(%rax), %rcx 764 if (Type == R_X86_64_DTPOFF64) { 765 write64le(Loc, Val); 766 return; 767 } 768 if (Type == R_X86_64_DTPOFF32) { 769 relocateOne(Loc, R_X86_64_TPOFF32, Val); 770 return; 771 } 772 773 const uint8_t Inst[] = { 774 0x66, 0x66, // .word 0x6666 775 0x66, // .byte 0x66 776 0x64, 0x48, 0x8b, 0x04, 0x25, 0x00, 0x00, 0x00, 0x00 // mov %fs:0,%rax 777 }; 778 memcpy(Loc - 3, Inst, sizeof(Inst)); 779 } 780 781 template <class ELFT> 782 void X86_64TargetInfo<ELFT>::relocateOne(uint8_t *Loc, uint32_t Type, 783 uint64_t Val) const { 784 switch (Type) { 785 case R_X86_64_32: 786 checkUInt<32>(Val, Type); 787 write32le(Loc, Val); 788 break; 789 case R_X86_64_32S: 790 case R_X86_64_TPOFF32: 791 case R_X86_64_GOT32: 792 case R_X86_64_GOTPCREL: 793 case R_X86_64_GOTPCRELX: 794 case R_X86_64_REX_GOTPCRELX: 795 case R_X86_64_PC32: 796 case R_X86_64_GOTTPOFF: 797 case R_X86_64_PLT32: 798 case R_X86_64_TLSGD: 799 case R_X86_64_TLSLD: 800 case R_X86_64_DTPOFF32: 801 case R_X86_64_SIZE32: 802 checkInt<32>(Val, Type); 803 write32le(Loc, Val); 804 break; 805 case R_X86_64_64: 806 case R_X86_64_DTPOFF64: 807 case R_X86_64_SIZE64: 808 case R_X86_64_PC64: 809 write64le(Loc, Val); 810 break; 811 default: 812 fatal("unrecognized reloc " + Twine(Type)); 813 } 814 } 815 816 template <class ELFT> 817 RelExpr X86_64TargetInfo<ELFT>::adjustRelaxExpr(uint32_t Type, 818 const uint8_t *Data, 819 RelExpr RelExpr) const { 820 if (Type != R_X86_64_GOTPCRELX && Type != R_X86_64_REX_GOTPCRELX) 821 return RelExpr; 822 const uint8_t Op = Data[-2]; 823 const uint8_t ModRm = Data[-1]; 824 // FIXME: When PIC is disabled and foo is defined locally in the 825 // lower 32 bit address space, memory operand in mov can be converted into 826 // immediate operand. Otherwise, mov must be changed to lea. We support only 827 // latter relaxation at this moment. 828 if (Op == 0x8b) 829 return R_RELAX_GOT_PC; 830 // Relax call and jmp. 831 if (Op == 0xff && (ModRm == 0x15 || ModRm == 0x25)) 832 return R_RELAX_GOT_PC; 833 834 // Relaxation of test, adc, add, and, cmp, or, sbb, sub, xor. 835 // If PIC then no relaxation is available. 836 // We also don't relax test/binop instructions without REX byte, 837 // they are 32bit operations and not common to have. 838 assert(Type == R_X86_64_REX_GOTPCRELX); 839 return Config->Pic ? RelExpr : R_RELAX_GOT_PC_NOPIC; 840 } 841 842 // A subset of relaxations can only be applied for no-PIC. This method 843 // handles such relaxations. Instructions encoding information was taken from: 844 // "Intel 64 and IA-32 Architectures Software Developer's Manual V2" 845 // (http://www.intel.com/content/dam/www/public/us/en/documents/manuals/ 846 // 64-ia-32-architectures-software-developer-instruction-set-reference-manual-325383.pdf) 847 template <class ELFT> 848 void X86_64TargetInfo<ELFT>::relaxGotNoPic(uint8_t *Loc, uint64_t Val, 849 uint8_t Op, uint8_t ModRm) const { 850 const uint8_t Rex = Loc[-3]; 851 // Convert "test %reg, foo@GOTPCREL(%rip)" to "test $foo, %reg". 852 if (Op == 0x85) { 853 // See "TEST-Logical Compare" (4-428 Vol. 2B), 854 // TEST r/m64, r64 uses "full" ModR / M byte (no opcode extension). 855 856 // ModR/M byte has form XX YYY ZZZ, where 857 // YYY is MODRM.reg(register 2), ZZZ is MODRM.rm(register 1). 858 // XX has different meanings: 859 // 00: The operand's memory address is in reg1. 860 // 01: The operand's memory address is reg1 + a byte-sized displacement. 861 // 10: The operand's memory address is reg1 + a word-sized displacement. 862 // 11: The operand is reg1 itself. 863 // If an instruction requires only one operand, the unused reg2 field 864 // holds extra opcode bits rather than a register code 865 // 0xC0 == 11 000 000 binary. 866 // 0x38 == 00 111 000 binary. 867 // We transfer reg2 to reg1 here as operand. 868 // See "2.1.3 ModR/M and SIB Bytes" (Vol. 2A 2-3). 869 Loc[-1] = 0xc0 | (ModRm & 0x38) >> 3; // ModR/M byte. 870 871 // Change opcode from TEST r/m64, r64 to TEST r/m64, imm32 872 // See "TEST-Logical Compare" (4-428 Vol. 2B). 873 Loc[-2] = 0xf7; 874 875 // Move R bit to the B bit in REX byte. 876 // REX byte is encoded as 0100WRXB, where 877 // 0100 is 4bit fixed pattern. 878 // REX.W When 1, a 64-bit operand size is used. Otherwise, when 0, the 879 // default operand size is used (which is 32-bit for most but not all 880 // instructions). 881 // REX.R This 1-bit value is an extension to the MODRM.reg field. 882 // REX.X This 1-bit value is an extension to the SIB.index field. 883 // REX.B This 1-bit value is an extension to the MODRM.rm field or the 884 // SIB.base field. 885 // See "2.2.1.2 More on REX Prefix Fields " (2-8 Vol. 2A). 886 Loc[-3] = (Rex & ~0x4) | (Rex & 0x4) >> 2; 887 relocateOne(Loc, R_X86_64_PC32, Val); 888 return; 889 } 890 891 // If we are here then we need to relax the adc, add, and, cmp, or, sbb, sub 892 // or xor operations. 893 894 // Convert "binop foo@GOTPCREL(%rip), %reg" to "binop $foo, %reg". 895 // Logic is close to one for test instruction above, but we also 896 // write opcode extension here, see below for details. 897 Loc[-1] = 0xc0 | (ModRm & 0x38) >> 3 | (Op & 0x3c); // ModR/M byte. 898 899 // Primary opcode is 0x81, opcode extension is one of: 900 // 000b = ADD, 001b is OR, 010b is ADC, 011b is SBB, 901 // 100b is AND, 101b is SUB, 110b is XOR, 111b is CMP. 902 // This value was wrote to MODRM.reg in a line above. 903 // See "3.2 INSTRUCTIONS (A-M)" (Vol. 2A 3-15), 904 // "INSTRUCTION SET REFERENCE, N-Z" (Vol. 2B 4-1) for 905 // descriptions about each operation. 906 Loc[-2] = 0x81; 907 Loc[-3] = (Rex & ~0x4) | (Rex & 0x4) >> 2; 908 relocateOne(Loc, R_X86_64_PC32, Val); 909 } 910 911 template <class ELFT> 912 void X86_64TargetInfo<ELFT>::relaxGot(uint8_t *Loc, uint64_t Val) const { 913 const uint8_t Op = Loc[-2]; 914 const uint8_t ModRm = Loc[-1]; 915 916 // Convert "mov foo@GOTPCREL(%rip),%reg" to "lea foo(%rip),%reg". 917 if (Op == 0x8b) { 918 Loc[-2] = 0x8d; 919 relocateOne(Loc, R_X86_64_PC32, Val); 920 return; 921 } 922 923 if (Op != 0xff) { 924 // We are relaxing a rip relative to an absolute, so compensate 925 // for the old -4 addend. 926 assert(!Config->Pic); 927 relaxGotNoPic(Loc, Val + 4, Op, ModRm); 928 return; 929 } 930 931 // Convert call/jmp instructions. 932 if (ModRm == 0x15) { 933 // ABI says we can convert "call *foo@GOTPCREL(%rip)" to "nop; call foo". 934 // Instead we convert to "addr32 call foo" where addr32 is an instruction 935 // prefix. That makes result expression to be a single instruction. 936 Loc[-2] = 0x67; // addr32 prefix 937 Loc[-1] = 0xe8; // call 938 relocateOne(Loc, R_X86_64_PC32, Val); 939 return; 940 } 941 942 // Convert "jmp *foo@GOTPCREL(%rip)" to "jmp foo; nop". 943 // jmp doesn't return, so it is fine to use nop here, it is just a stub. 944 assert(ModRm == 0x25); 945 Loc[-2] = 0xe9; // jmp 946 Loc[3] = 0x90; // nop 947 relocateOne(Loc - 1, R_X86_64_PC32, Val + 1); 948 } 949 950 // Relocation masks following the #lo(value), #hi(value), #ha(value), 951 // #higher(value), #highera(value), #highest(value), and #highesta(value) 952 // macros defined in section 4.5.1. Relocation Types of the PPC-elf64abi 953 // document. 954 static uint16_t applyPPCLo(uint64_t V) { return V; } 955 static uint16_t applyPPCHi(uint64_t V) { return V >> 16; } 956 static uint16_t applyPPCHa(uint64_t V) { return (V + 0x8000) >> 16; } 957 static uint16_t applyPPCHigher(uint64_t V) { return V >> 32; } 958 static uint16_t applyPPCHighera(uint64_t V) { return (V + 0x8000) >> 32; } 959 static uint16_t applyPPCHighest(uint64_t V) { return V >> 48; } 960 static uint16_t applyPPCHighesta(uint64_t V) { return (V + 0x8000) >> 48; } 961 962 PPCTargetInfo::PPCTargetInfo() {} 963 964 void PPCTargetInfo::relocateOne(uint8_t *Loc, uint32_t Type, 965 uint64_t Val) const { 966 switch (Type) { 967 case R_PPC_ADDR16_HA: 968 write16be(Loc, applyPPCHa(Val)); 969 break; 970 case R_PPC_ADDR16_LO: 971 write16be(Loc, applyPPCLo(Val)); 972 break; 973 default: 974 fatal("unrecognized reloc " + Twine(Type)); 975 } 976 } 977 978 RelExpr PPCTargetInfo::getRelExpr(uint32_t Type, const SymbolBody &S) const { 979 return R_ABS; 980 } 981 982 PPC64TargetInfo::PPC64TargetInfo() { 983 PltRel = GotRel = R_PPC64_GLOB_DAT; 984 RelativeRel = R_PPC64_RELATIVE; 985 GotEntrySize = 8; 986 GotPltEntrySize = 8; 987 PltEntrySize = 32; 988 PltHeaderSize = 0; 989 990 // We need 64K pages (at least under glibc/Linux, the loader won't 991 // set different permissions on a finer granularity than that). 992 PageSize = 65536; 993 994 // The PPC64 ELF ABI v1 spec, says: 995 // 996 // It is normally desirable to put segments with different characteristics 997 // in separate 256 Mbyte portions of the address space, to give the 998 // operating system full paging flexibility in the 64-bit address space. 999 // 1000 // And because the lowest non-zero 256M boundary is 0x10000000, PPC64 linkers 1001 // use 0x10000000 as the starting address. 1002 DefaultImageBase = 0x10000000; 1003 } 1004 1005 static uint64_t PPC64TocOffset = 0x8000; 1006 1007 uint64_t getPPC64TocBase() { 1008 // The TOC consists of sections .got, .toc, .tocbss, .plt in that order. The 1009 // TOC starts where the first of these sections starts. We always create a 1010 // .got when we see a relocation that uses it, so for us the start is always 1011 // the .got. 1012 uint64_t TocVA = Out<ELF64BE>::Got->getVA(); 1013 1014 // Per the ppc64-elf-linux ABI, The TOC base is TOC value plus 0x8000 1015 // thus permitting a full 64 Kbytes segment. Note that the glibc startup 1016 // code (crt1.o) assumes that you can get from the TOC base to the 1017 // start of the .toc section with only a single (signed) 16-bit relocation. 1018 return TocVA + PPC64TocOffset; 1019 } 1020 1021 RelExpr PPC64TargetInfo::getRelExpr(uint32_t Type, const SymbolBody &S) const { 1022 switch (Type) { 1023 default: 1024 return R_ABS; 1025 case R_PPC64_TOC16: 1026 case R_PPC64_TOC16_DS: 1027 case R_PPC64_TOC16_HA: 1028 case R_PPC64_TOC16_HI: 1029 case R_PPC64_TOC16_LO: 1030 case R_PPC64_TOC16_LO_DS: 1031 return R_GOTREL; 1032 case R_PPC64_TOC: 1033 return R_PPC_TOC; 1034 case R_PPC64_REL24: 1035 return R_PPC_PLT_OPD; 1036 } 1037 } 1038 1039 void PPC64TargetInfo::writePlt(uint8_t *Buf, uint64_t GotEntryAddr, 1040 uint64_t PltEntryAddr, int32_t Index, 1041 unsigned RelOff) const { 1042 uint64_t Off = GotEntryAddr - getPPC64TocBase(); 1043 1044 // FIXME: What we should do, in theory, is get the offset of the function 1045 // descriptor in the .opd section, and use that as the offset from %r2 (the 1046 // TOC-base pointer). Instead, we have the GOT-entry offset, and that will 1047 // be a pointer to the function descriptor in the .opd section. Using 1048 // this scheme is simpler, but requires an extra indirection per PLT dispatch. 1049 1050 write32be(Buf, 0xf8410028); // std %r2, 40(%r1) 1051 write32be(Buf + 4, 0x3d620000 | applyPPCHa(Off)); // addis %r11, %r2, X@ha 1052 write32be(Buf + 8, 0xe98b0000 | applyPPCLo(Off)); // ld %r12, X@l(%r11) 1053 write32be(Buf + 12, 0xe96c0000); // ld %r11,0(%r12) 1054 write32be(Buf + 16, 0x7d6903a6); // mtctr %r11 1055 write32be(Buf + 20, 0xe84c0008); // ld %r2,8(%r12) 1056 write32be(Buf + 24, 0xe96c0010); // ld %r11,16(%r12) 1057 write32be(Buf + 28, 0x4e800420); // bctr 1058 } 1059 1060 static std::pair<uint32_t, uint64_t> toAddr16Rel(uint32_t Type, uint64_t Val) { 1061 uint64_t V = Val - PPC64TocOffset; 1062 switch (Type) { 1063 case R_PPC64_TOC16: return {R_PPC64_ADDR16, V}; 1064 case R_PPC64_TOC16_DS: return {R_PPC64_ADDR16_DS, V}; 1065 case R_PPC64_TOC16_HA: return {R_PPC64_ADDR16_HA, V}; 1066 case R_PPC64_TOC16_HI: return {R_PPC64_ADDR16_HI, V}; 1067 case R_PPC64_TOC16_LO: return {R_PPC64_ADDR16_LO, V}; 1068 case R_PPC64_TOC16_LO_DS: return {R_PPC64_ADDR16_LO_DS, V}; 1069 default: return {Type, Val}; 1070 } 1071 } 1072 1073 void PPC64TargetInfo::relocateOne(uint8_t *Loc, uint32_t Type, 1074 uint64_t Val) const { 1075 // For a TOC-relative relocation, proceed in terms of the corresponding 1076 // ADDR16 relocation type. 1077 std::tie(Type, Val) = toAddr16Rel(Type, Val); 1078 1079 switch (Type) { 1080 case R_PPC64_ADDR14: { 1081 checkAlignment<4>(Val, Type); 1082 // Preserve the AA/LK bits in the branch instruction 1083 uint8_t AALK = Loc[3]; 1084 write16be(Loc + 2, (AALK & 3) | (Val & 0xfffc)); 1085 break; 1086 } 1087 case R_PPC64_ADDR16: 1088 checkInt<16>(Val, Type); 1089 write16be(Loc, Val); 1090 break; 1091 case R_PPC64_ADDR16_DS: 1092 checkInt<16>(Val, Type); 1093 write16be(Loc, (read16be(Loc) & 3) | (Val & ~3)); 1094 break; 1095 case R_PPC64_ADDR16_HA: 1096 case R_PPC64_REL16_HA: 1097 write16be(Loc, applyPPCHa(Val)); 1098 break; 1099 case R_PPC64_ADDR16_HI: 1100 case R_PPC64_REL16_HI: 1101 write16be(Loc, applyPPCHi(Val)); 1102 break; 1103 case R_PPC64_ADDR16_HIGHER: 1104 write16be(Loc, applyPPCHigher(Val)); 1105 break; 1106 case R_PPC64_ADDR16_HIGHERA: 1107 write16be(Loc, applyPPCHighera(Val)); 1108 break; 1109 case R_PPC64_ADDR16_HIGHEST: 1110 write16be(Loc, applyPPCHighest(Val)); 1111 break; 1112 case R_PPC64_ADDR16_HIGHESTA: 1113 write16be(Loc, applyPPCHighesta(Val)); 1114 break; 1115 case R_PPC64_ADDR16_LO: 1116 write16be(Loc, applyPPCLo(Val)); 1117 break; 1118 case R_PPC64_ADDR16_LO_DS: 1119 case R_PPC64_REL16_LO: 1120 write16be(Loc, (read16be(Loc) & 3) | (applyPPCLo(Val) & ~3)); 1121 break; 1122 case R_PPC64_ADDR32: 1123 case R_PPC64_REL32: 1124 checkInt<32>(Val, Type); 1125 write32be(Loc, Val); 1126 break; 1127 case R_PPC64_ADDR64: 1128 case R_PPC64_REL64: 1129 case R_PPC64_TOC: 1130 write64be(Loc, Val); 1131 break; 1132 case R_PPC64_REL24: { 1133 uint32_t Mask = 0x03FFFFFC; 1134 checkInt<24>(Val, Type); 1135 write32be(Loc, (read32be(Loc) & ~Mask) | (Val & Mask)); 1136 break; 1137 } 1138 default: 1139 fatal("unrecognized reloc " + Twine(Type)); 1140 } 1141 } 1142 1143 AArch64TargetInfo::AArch64TargetInfo() { 1144 CopyRel = R_AARCH64_COPY; 1145 RelativeRel = R_AARCH64_RELATIVE; 1146 IRelativeRel = R_AARCH64_IRELATIVE; 1147 GotRel = R_AARCH64_GLOB_DAT; 1148 PltRel = R_AARCH64_JUMP_SLOT; 1149 TlsDescRel = R_AARCH64_TLSDESC; 1150 TlsGotRel = R_AARCH64_TLS_TPREL64; 1151 GotEntrySize = 8; 1152 GotPltEntrySize = 8; 1153 PltEntrySize = 16; 1154 PltHeaderSize = 32; 1155 1156 // It doesn't seem to be documented anywhere, but tls on aarch64 uses variant 1157 // 1 of the tls structures and the tcb size is 16. 1158 TcbSize = 16; 1159 } 1160 1161 RelExpr AArch64TargetInfo::getRelExpr(uint32_t Type, 1162 const SymbolBody &S) const { 1163 switch (Type) { 1164 default: 1165 return R_ABS; 1166 case R_AARCH64_TLSDESC_ADR_PAGE21: 1167 return R_TLSDESC_PAGE; 1168 case R_AARCH64_TLSDESC_LD64_LO12_NC: 1169 case R_AARCH64_TLSDESC_ADD_LO12_NC: 1170 return R_TLSDESC; 1171 case R_AARCH64_TLSDESC_CALL: 1172 return R_HINT; 1173 case R_AARCH64_TLSLE_ADD_TPREL_HI12: 1174 case R_AARCH64_TLSLE_ADD_TPREL_LO12_NC: 1175 return R_TLS; 1176 case R_AARCH64_CALL26: 1177 case R_AARCH64_CONDBR19: 1178 case R_AARCH64_JUMP26: 1179 case R_AARCH64_TSTBR14: 1180 return R_PLT_PC; 1181 case R_AARCH64_PREL16: 1182 case R_AARCH64_PREL32: 1183 case R_AARCH64_PREL64: 1184 case R_AARCH64_ADR_PREL_LO21: 1185 return R_PC; 1186 case R_AARCH64_ADR_PREL_PG_HI21: 1187 return R_PAGE_PC; 1188 case R_AARCH64_LD64_GOT_LO12_NC: 1189 case R_AARCH64_TLSIE_LD64_GOTTPREL_LO12_NC: 1190 return R_GOT; 1191 case R_AARCH64_ADR_GOT_PAGE: 1192 case R_AARCH64_TLSIE_ADR_GOTTPREL_PAGE21: 1193 return R_GOT_PAGE_PC; 1194 } 1195 } 1196 1197 RelExpr AArch64TargetInfo::adjustRelaxExpr(uint32_t Type, const uint8_t *Data, 1198 RelExpr Expr) const { 1199 if (Expr == R_RELAX_TLS_GD_TO_IE) { 1200 if (Type == R_AARCH64_TLSDESC_ADR_PAGE21) 1201 return R_RELAX_TLS_GD_TO_IE_PAGE_PC; 1202 return R_RELAX_TLS_GD_TO_IE_ABS; 1203 } 1204 return Expr; 1205 } 1206 1207 bool AArch64TargetInfo::usesOnlyLowPageBits(uint32_t Type) const { 1208 switch (Type) { 1209 default: 1210 return false; 1211 case R_AARCH64_ADD_ABS_LO12_NC: 1212 case R_AARCH64_LD64_GOT_LO12_NC: 1213 case R_AARCH64_LDST128_ABS_LO12_NC: 1214 case R_AARCH64_LDST16_ABS_LO12_NC: 1215 case R_AARCH64_LDST32_ABS_LO12_NC: 1216 case R_AARCH64_LDST64_ABS_LO12_NC: 1217 case R_AARCH64_LDST8_ABS_LO12_NC: 1218 case R_AARCH64_TLSDESC_ADD_LO12_NC: 1219 case R_AARCH64_TLSDESC_LD64_LO12_NC: 1220 case R_AARCH64_TLSIE_LD64_GOTTPREL_LO12_NC: 1221 return true; 1222 } 1223 } 1224 1225 bool AArch64TargetInfo::isTlsInitialExecRel(uint32_t Type) const { 1226 return Type == R_AARCH64_TLSIE_ADR_GOTTPREL_PAGE21 || 1227 Type == R_AARCH64_TLSIE_LD64_GOTTPREL_LO12_NC; 1228 } 1229 1230 uint32_t AArch64TargetInfo::getDynRel(uint32_t Type) const { 1231 if (Type == R_AARCH64_ABS32 || Type == R_AARCH64_ABS64) 1232 return Type; 1233 // Keep it going with a dummy value so that we can find more reloc errors. 1234 errorDynRel(Type); 1235 return R_AARCH64_ABS32; 1236 } 1237 1238 void AArch64TargetInfo::writeGotPlt(uint8_t *Buf, const SymbolBody &) const { 1239 write64le(Buf, Out<ELF64LE>::Plt->getVA()); 1240 } 1241 1242 static uint64_t getAArch64Page(uint64_t Expr) { 1243 return Expr & (~static_cast<uint64_t>(0xFFF)); 1244 } 1245 1246 void AArch64TargetInfo::writePltHeader(uint8_t *Buf) const { 1247 const uint8_t PltData[] = { 1248 0xf0, 0x7b, 0xbf, 0xa9, // stp x16, x30, [sp,#-16]! 1249 0x10, 0x00, 0x00, 0x90, // adrp x16, Page(&(.plt.got[2])) 1250 0x11, 0x02, 0x40, 0xf9, // ldr x17, [x16, Offset(&(.plt.got[2]))] 1251 0x10, 0x02, 0x00, 0x91, // add x16, x16, Offset(&(.plt.got[2])) 1252 0x20, 0x02, 0x1f, 0xd6, // br x17 1253 0x1f, 0x20, 0x03, 0xd5, // nop 1254 0x1f, 0x20, 0x03, 0xd5, // nop 1255 0x1f, 0x20, 0x03, 0xd5 // nop 1256 }; 1257 memcpy(Buf, PltData, sizeof(PltData)); 1258 1259 uint64_t Got = Out<ELF64LE>::GotPlt->getVA(); 1260 uint64_t Plt = Out<ELF64LE>::Plt->getVA(); 1261 relocateOne(Buf + 4, R_AARCH64_ADR_PREL_PG_HI21, 1262 getAArch64Page(Got + 16) - getAArch64Page(Plt + 4)); 1263 relocateOne(Buf + 8, R_AARCH64_LDST64_ABS_LO12_NC, Got + 16); 1264 relocateOne(Buf + 12, R_AARCH64_ADD_ABS_LO12_NC, Got + 16); 1265 } 1266 1267 void AArch64TargetInfo::writePlt(uint8_t *Buf, uint64_t GotEntryAddr, 1268 uint64_t PltEntryAddr, int32_t Index, 1269 unsigned RelOff) const { 1270 const uint8_t Inst[] = { 1271 0x10, 0x00, 0x00, 0x90, // adrp x16, Page(&(.plt.got[n])) 1272 0x11, 0x02, 0x40, 0xf9, // ldr x17, [x16, Offset(&(.plt.got[n]))] 1273 0x10, 0x02, 0x00, 0x91, // add x16, x16, Offset(&(.plt.got[n])) 1274 0x20, 0x02, 0x1f, 0xd6 // br x17 1275 }; 1276 memcpy(Buf, Inst, sizeof(Inst)); 1277 1278 relocateOne(Buf, R_AARCH64_ADR_PREL_PG_HI21, 1279 getAArch64Page(GotEntryAddr) - getAArch64Page(PltEntryAddr)); 1280 relocateOne(Buf + 4, R_AARCH64_LDST64_ABS_LO12_NC, GotEntryAddr); 1281 relocateOne(Buf + 8, R_AARCH64_ADD_ABS_LO12_NC, GotEntryAddr); 1282 } 1283 1284 static void updateAArch64Addr(uint8_t *L, uint64_t Imm) { 1285 uint32_t ImmLo = (Imm & 0x3) << 29; 1286 uint32_t ImmHi = (Imm & 0x1FFFFC) << 3; 1287 uint64_t Mask = (0x3 << 29) | (0x1FFFFC << 3); 1288 write32le(L, (read32le(L) & ~Mask) | ImmLo | ImmHi); 1289 } 1290 1291 static inline void updateAArch64Add(uint8_t *L, uint64_t Imm) { 1292 or32le(L, (Imm & 0xFFF) << 10); 1293 } 1294 1295 void AArch64TargetInfo::relocateOne(uint8_t *Loc, uint32_t Type, 1296 uint64_t Val) const { 1297 switch (Type) { 1298 case R_AARCH64_ABS16: 1299 case R_AARCH64_PREL16: 1300 checkIntUInt<16>(Val, Type); 1301 write16le(Loc, Val); 1302 break; 1303 case R_AARCH64_ABS32: 1304 case R_AARCH64_PREL32: 1305 checkIntUInt<32>(Val, Type); 1306 write32le(Loc, Val); 1307 break; 1308 case R_AARCH64_ABS64: 1309 case R_AARCH64_PREL64: 1310 write64le(Loc, Val); 1311 break; 1312 case R_AARCH64_ADD_ABS_LO12_NC: 1313 // This relocation stores 12 bits and there's no instruction 1314 // to do it. Instead, we do a 32 bits store of the value 1315 // of r_addend bitwise-or'ed Loc. This assumes that the addend 1316 // bits in Loc are zero. 1317 or32le(Loc, (Val & 0xFFF) << 10); 1318 break; 1319 case R_AARCH64_ADR_GOT_PAGE: 1320 case R_AARCH64_ADR_PREL_PG_HI21: 1321 case R_AARCH64_TLSIE_ADR_GOTTPREL_PAGE21: 1322 case R_AARCH64_TLSDESC_ADR_PAGE21: 1323 checkInt<33>(Val, Type); 1324 updateAArch64Addr(Loc, Val >> 12); 1325 break; 1326 case R_AARCH64_ADR_PREL_LO21: 1327 checkInt<21>(Val, Type); 1328 updateAArch64Addr(Loc, Val); 1329 break; 1330 case R_AARCH64_CALL26: 1331 case R_AARCH64_JUMP26: 1332 checkInt<28>(Val, Type); 1333 or32le(Loc, (Val & 0x0FFFFFFC) >> 2); 1334 break; 1335 case R_AARCH64_CONDBR19: 1336 checkInt<21>(Val, Type); 1337 or32le(Loc, (Val & 0x1FFFFC) << 3); 1338 break; 1339 case R_AARCH64_LD64_GOT_LO12_NC: 1340 case R_AARCH64_TLSIE_LD64_GOTTPREL_LO12_NC: 1341 case R_AARCH64_TLSDESC_LD64_LO12_NC: 1342 checkAlignment<8>(Val, Type); 1343 or32le(Loc, (Val & 0xFF8) << 7); 1344 break; 1345 case R_AARCH64_LDST128_ABS_LO12_NC: 1346 or32le(Loc, (Val & 0x0FF8) << 6); 1347 break; 1348 case R_AARCH64_LDST16_ABS_LO12_NC: 1349 or32le(Loc, (Val & 0x0FFC) << 9); 1350 break; 1351 case R_AARCH64_LDST8_ABS_LO12_NC: 1352 or32le(Loc, (Val & 0xFFF) << 10); 1353 break; 1354 case R_AARCH64_LDST32_ABS_LO12_NC: 1355 or32le(Loc, (Val & 0xFFC) << 8); 1356 break; 1357 case R_AARCH64_LDST64_ABS_LO12_NC: 1358 or32le(Loc, (Val & 0xFF8) << 7); 1359 break; 1360 case R_AARCH64_MOVW_UABS_G0_NC: 1361 or32le(Loc, (Val & 0xFFFF) << 5); 1362 break; 1363 case R_AARCH64_MOVW_UABS_G1_NC: 1364 or32le(Loc, (Val & 0xFFFF0000) >> 11); 1365 break; 1366 case R_AARCH64_MOVW_UABS_G2_NC: 1367 or32le(Loc, (Val & 0xFFFF00000000) >> 27); 1368 break; 1369 case R_AARCH64_MOVW_UABS_G3: 1370 or32le(Loc, (Val & 0xFFFF000000000000) >> 43); 1371 break; 1372 case R_AARCH64_TSTBR14: 1373 checkInt<16>(Val, Type); 1374 or32le(Loc, (Val & 0xFFFC) << 3); 1375 break; 1376 case R_AARCH64_TLSLE_ADD_TPREL_HI12: 1377 checkInt<24>(Val, Type); 1378 updateAArch64Add(Loc, Val >> 12); 1379 break; 1380 case R_AARCH64_TLSLE_ADD_TPREL_LO12_NC: 1381 case R_AARCH64_TLSDESC_ADD_LO12_NC: 1382 updateAArch64Add(Loc, Val); 1383 break; 1384 default: 1385 fatal("unrecognized reloc " + Twine(Type)); 1386 } 1387 } 1388 1389 void AArch64TargetInfo::relaxTlsGdToLe(uint8_t *Loc, uint32_t Type, 1390 uint64_t Val) const { 1391 // TLSDESC Global-Dynamic relocation are in the form: 1392 // adrp x0, :tlsdesc:v [R_AARCH64_TLSDESC_ADR_PAGE21] 1393 // ldr x1, [x0, #:tlsdesc_lo12:v [R_AARCH64_TLSDESC_LD64_LO12_NC] 1394 // add x0, x0, :tlsdesc_los:v [_AARCH64_TLSDESC_ADD_LO12_NC] 1395 // .tlsdesccall [R_AARCH64_TLSDESC_CALL] 1396 // blr x1 1397 // And it can optimized to: 1398 // movz x0, #0x0, lsl #16 1399 // movk x0, #0x10 1400 // nop 1401 // nop 1402 checkUInt<32>(Val, Type); 1403 1404 switch (Type) { 1405 case R_AARCH64_TLSDESC_ADD_LO12_NC: 1406 case R_AARCH64_TLSDESC_CALL: 1407 write32le(Loc, 0xd503201f); // nop 1408 return; 1409 case R_AARCH64_TLSDESC_ADR_PAGE21: 1410 write32le(Loc, 0xd2a00000 | (((Val >> 16) & 0xffff) << 5)); // movz 1411 return; 1412 case R_AARCH64_TLSDESC_LD64_LO12_NC: 1413 write32le(Loc, 0xf2800000 | ((Val & 0xffff) << 5)); // movk 1414 return; 1415 default: 1416 llvm_unreachable("unsupported relocation for TLS GD to LE relaxation"); 1417 } 1418 } 1419 1420 void AArch64TargetInfo::relaxTlsGdToIe(uint8_t *Loc, uint32_t Type, 1421 uint64_t Val) const { 1422 // TLSDESC Global-Dynamic relocation are in the form: 1423 // adrp x0, :tlsdesc:v [R_AARCH64_TLSDESC_ADR_PAGE21] 1424 // ldr x1, [x0, #:tlsdesc_lo12:v [R_AARCH64_TLSDESC_LD64_LO12_NC] 1425 // add x0, x0, :tlsdesc_los:v [_AARCH64_TLSDESC_ADD_LO12_NC] 1426 // .tlsdesccall [R_AARCH64_TLSDESC_CALL] 1427 // blr x1 1428 // And it can optimized to: 1429 // adrp x0, :gottprel:v 1430 // ldr x0, [x0, :gottprel_lo12:v] 1431 // nop 1432 // nop 1433 1434 switch (Type) { 1435 case R_AARCH64_TLSDESC_ADD_LO12_NC: 1436 case R_AARCH64_TLSDESC_CALL: 1437 write32le(Loc, 0xd503201f); // nop 1438 break; 1439 case R_AARCH64_TLSDESC_ADR_PAGE21: 1440 write32le(Loc, 0x90000000); // adrp 1441 relocateOne(Loc, R_AARCH64_TLSIE_ADR_GOTTPREL_PAGE21, Val); 1442 break; 1443 case R_AARCH64_TLSDESC_LD64_LO12_NC: 1444 write32le(Loc, 0xf9400000); // ldr 1445 relocateOne(Loc, R_AARCH64_TLSIE_LD64_GOTTPREL_LO12_NC, Val); 1446 break; 1447 default: 1448 llvm_unreachable("unsupported relocation for TLS GD to LE relaxation"); 1449 } 1450 } 1451 1452 void AArch64TargetInfo::relaxTlsIeToLe(uint8_t *Loc, uint32_t Type, 1453 uint64_t Val) const { 1454 checkUInt<32>(Val, Type); 1455 1456 if (Type == R_AARCH64_TLSIE_ADR_GOTTPREL_PAGE21) { 1457 // Generate MOVZ. 1458 uint32_t RegNo = read32le(Loc) & 0x1f; 1459 write32le(Loc, (0xd2a00000 | RegNo) | (((Val >> 16) & 0xffff) << 5)); 1460 return; 1461 } 1462 if (Type == R_AARCH64_TLSIE_LD64_GOTTPREL_LO12_NC) { 1463 // Generate MOVK. 1464 uint32_t RegNo = read32le(Loc) & 0x1f; 1465 write32le(Loc, (0xf2800000 | RegNo) | ((Val & 0xffff) << 5)); 1466 return; 1467 } 1468 llvm_unreachable("invalid relocation for TLS IE to LE relaxation"); 1469 } 1470 1471 AMDGPUTargetInfo::AMDGPUTargetInfo() { 1472 RelativeRel = R_AMDGPU_REL64; 1473 GotRel = R_AMDGPU_ABS64; 1474 GotEntrySize = 8; 1475 } 1476 1477 void AMDGPUTargetInfo::relocateOne(uint8_t *Loc, uint32_t Type, 1478 uint64_t Val) const { 1479 switch (Type) { 1480 case R_AMDGPU_ABS32: 1481 case R_AMDGPU_GOTPCREL: 1482 case R_AMDGPU_REL32: 1483 write32le(Loc, Val); 1484 break; 1485 default: 1486 fatal("unrecognized reloc " + Twine(Type)); 1487 } 1488 } 1489 1490 RelExpr AMDGPUTargetInfo::getRelExpr(uint32_t Type, const SymbolBody &S) const { 1491 switch (Type) { 1492 case R_AMDGPU_ABS32: 1493 return R_ABS; 1494 case R_AMDGPU_REL32: 1495 return R_PC; 1496 case R_AMDGPU_GOTPCREL: 1497 return R_GOT_PC; 1498 default: 1499 fatal("do not know how to handle relocation " + Twine(Type)); 1500 } 1501 } 1502 1503 ARMTargetInfo::ARMTargetInfo() { 1504 CopyRel = R_ARM_COPY; 1505 RelativeRel = R_ARM_RELATIVE; 1506 IRelativeRel = R_ARM_IRELATIVE; 1507 GotRel = R_ARM_GLOB_DAT; 1508 PltRel = R_ARM_JUMP_SLOT; 1509 TlsGotRel = R_ARM_TLS_TPOFF32; 1510 TlsModuleIndexRel = R_ARM_TLS_DTPMOD32; 1511 TlsOffsetRel = R_ARM_TLS_DTPOFF32; 1512 GotEntrySize = 4; 1513 GotPltEntrySize = 4; 1514 PltEntrySize = 16; 1515 PltHeaderSize = 20; 1516 // ARM uses Variant 1 TLS 1517 TcbSize = 8; 1518 NeedsThunks = true; 1519 } 1520 1521 RelExpr ARMTargetInfo::getRelExpr(uint32_t Type, const SymbolBody &S) const { 1522 switch (Type) { 1523 default: 1524 return R_ABS; 1525 case R_ARM_THM_JUMP11: 1526 return R_PC; 1527 case R_ARM_CALL: 1528 case R_ARM_JUMP24: 1529 case R_ARM_PC24: 1530 case R_ARM_PLT32: 1531 case R_ARM_THM_JUMP19: 1532 case R_ARM_THM_JUMP24: 1533 case R_ARM_THM_CALL: 1534 return R_PLT_PC; 1535 case R_ARM_GOTOFF32: 1536 // (S + A) - GOT_ORG 1537 return R_GOTREL; 1538 case R_ARM_GOT_BREL: 1539 // GOT(S) + A - GOT_ORG 1540 return R_GOT_OFF; 1541 case R_ARM_GOT_PREL: 1542 case R_ARM_TLS_IE32: 1543 // GOT(S) + A - P 1544 return R_GOT_PC; 1545 case R_ARM_TARGET1: 1546 return Config->Target1Rel ? R_PC : R_ABS; 1547 case R_ARM_TLS_GD32: 1548 return R_TLSGD_PC; 1549 case R_ARM_TLS_LDM32: 1550 return R_TLSLD_PC; 1551 case R_ARM_BASE_PREL: 1552 // B(S) + A - P 1553 // FIXME: currently B(S) assumed to be .got, this may not hold for all 1554 // platforms. 1555 return R_GOTONLY_PC; 1556 case R_ARM_MOVW_PREL_NC: 1557 case R_ARM_MOVT_PREL: 1558 case R_ARM_PREL31: 1559 case R_ARM_REL32: 1560 case R_ARM_THM_MOVW_PREL_NC: 1561 case R_ARM_THM_MOVT_PREL: 1562 return R_PC; 1563 case R_ARM_TLS_LE32: 1564 return R_TLS; 1565 } 1566 } 1567 1568 uint32_t ARMTargetInfo::getDynRel(uint32_t Type) const { 1569 if (Type == R_ARM_TARGET1 && !Config->Target1Rel) 1570 return R_ARM_ABS32; 1571 if (Type == R_ARM_ABS32) 1572 return Type; 1573 // Keep it going with a dummy value so that we can find more reloc errors. 1574 errorDynRel(Type); 1575 return R_ARM_ABS32; 1576 } 1577 1578 void ARMTargetInfo::writeGotPlt(uint8_t *Buf, const SymbolBody &) const { 1579 write32le(Buf, Out<ELF32LE>::Plt->getVA()); 1580 } 1581 1582 void ARMTargetInfo::writePltHeader(uint8_t *Buf) const { 1583 const uint8_t PltData[] = { 1584 0x04, 0xe0, 0x2d, 0xe5, // str lr, [sp,#-4]! 1585 0x04, 0xe0, 0x9f, 0xe5, // ldr lr, L2 1586 0x0e, 0xe0, 0x8f, 0xe0, // L1: add lr, pc, lr 1587 0x08, 0xf0, 0xbe, 0xe5, // ldr pc, [lr, #8] 1588 0x00, 0x00, 0x00, 0x00, // L2: .word &(.got.plt) - L1 - 8 1589 }; 1590 memcpy(Buf, PltData, sizeof(PltData)); 1591 uint64_t GotPlt = Out<ELF32LE>::GotPlt->getVA(); 1592 uint64_t L1 = Out<ELF32LE>::Plt->getVA() + 8; 1593 write32le(Buf + 16, GotPlt - L1 - 8); 1594 } 1595 1596 void ARMTargetInfo::writePlt(uint8_t *Buf, uint64_t GotEntryAddr, 1597 uint64_t PltEntryAddr, int32_t Index, 1598 unsigned RelOff) const { 1599 // FIXME: Using simple code sequence with simple relocations. 1600 // There is a more optimal sequence but it requires support for the group 1601 // relocations. See ELF for the ARM Architecture Appendix A.3 1602 const uint8_t PltData[] = { 1603 0x04, 0xc0, 0x9f, 0xe5, // ldr ip, L2 1604 0x0f, 0xc0, 0x8c, 0xe0, // L1: add ip, ip, pc 1605 0x00, 0xf0, 0x9c, 0xe5, // ldr pc, [ip] 1606 0x00, 0x00, 0x00, 0x00, // L2: .word Offset(&(.plt.got) - L1 - 8 1607 }; 1608 memcpy(Buf, PltData, sizeof(PltData)); 1609 uint64_t L1 = PltEntryAddr + 4; 1610 write32le(Buf + 12, GotEntryAddr - L1 - 8); 1611 } 1612 1613 RelExpr ARMTargetInfo::getThunkExpr(RelExpr Expr, uint32_t RelocType, 1614 const InputFile &File, 1615 const SymbolBody &S) const { 1616 // A state change from ARM to Thumb and vice versa must go through an 1617 // interworking thunk if the relocation type is not R_ARM_CALL or 1618 // R_ARM_THM_CALL. 1619 switch (RelocType) { 1620 case R_ARM_PC24: 1621 case R_ARM_PLT32: 1622 case R_ARM_JUMP24: 1623 // Source is ARM, all PLT entries are ARM so no interworking required. 1624 // Otherwise we need to interwork if Symbol has bit 0 set (Thumb). 1625 if (Expr == R_PC && ((S.getVA<ELF32LE>() & 1) == 1)) 1626 return R_THUNK_PC; 1627 break; 1628 case R_ARM_THM_JUMP19: 1629 case R_ARM_THM_JUMP24: 1630 // Source is Thumb, all PLT entries are ARM so interworking is required. 1631 // Otherwise we need to interwork if Symbol has bit 0 clear (ARM). 1632 if (Expr == R_PLT_PC) 1633 return R_THUNK_PLT_PC; 1634 if ((S.getVA<ELF32LE>() & 1) == 0) 1635 return R_THUNK_PC; 1636 break; 1637 } 1638 return Expr; 1639 } 1640 1641 void ARMTargetInfo::relocateOne(uint8_t *Loc, uint32_t Type, 1642 uint64_t Val) const { 1643 switch (Type) { 1644 case R_ARM_NONE: 1645 break; 1646 case R_ARM_ABS32: 1647 case R_ARM_BASE_PREL: 1648 case R_ARM_GOTOFF32: 1649 case R_ARM_GOT_BREL: 1650 case R_ARM_GOT_PREL: 1651 case R_ARM_REL32: 1652 case R_ARM_TARGET1: 1653 case R_ARM_TLS_GD32: 1654 case R_ARM_TLS_IE32: 1655 case R_ARM_TLS_LDM32: 1656 case R_ARM_TLS_LDO32: 1657 case R_ARM_TLS_LE32: 1658 write32le(Loc, Val); 1659 break; 1660 case R_ARM_PREL31: 1661 checkInt<31>(Val, Type); 1662 write32le(Loc, (read32le(Loc) & 0x80000000) | (Val & ~0x80000000)); 1663 break; 1664 case R_ARM_CALL: 1665 // R_ARM_CALL is used for BL and BLX instructions, depending on the 1666 // value of bit 0 of Val, we must select a BL or BLX instruction 1667 if (Val & 1) { 1668 // If bit 0 of Val is 1 the target is Thumb, we must select a BLX. 1669 // The BLX encoding is 0xfa:H:imm24 where Val = imm24:H:'1' 1670 checkInt<26>(Val, Type); 1671 write32le(Loc, 0xfa000000 | // opcode 1672 ((Val & 2) << 23) | // H 1673 ((Val >> 2) & 0x00ffffff)); // imm24 1674 break; 1675 } 1676 if ((read32le(Loc) & 0xfe000000) == 0xfa000000) 1677 // BLX (always unconditional) instruction to an ARM Target, select an 1678 // unconditional BL. 1679 write32le(Loc, 0xeb000000 | (read32le(Loc) & 0x00ffffff)); 1680 // fall through as BL encoding is shared with B 1681 case R_ARM_JUMP24: 1682 case R_ARM_PC24: 1683 case R_ARM_PLT32: 1684 checkInt<26>(Val, Type); 1685 write32le(Loc, (read32le(Loc) & ~0x00ffffff) | ((Val >> 2) & 0x00ffffff)); 1686 break; 1687 case R_ARM_THM_JUMP11: 1688 checkInt<12>(Val, Type); 1689 write16le(Loc, (read32le(Loc) & 0xf800) | ((Val >> 1) & 0x07ff)); 1690 break; 1691 case R_ARM_THM_JUMP19: 1692 // Encoding T3: Val = S:J2:J1:imm6:imm11:0 1693 checkInt<21>(Val, Type); 1694 write16le(Loc, 1695 (read16le(Loc) & 0xfbc0) | // opcode cond 1696 ((Val >> 10) & 0x0400) | // S 1697 ((Val >> 12) & 0x003f)); // imm6 1698 write16le(Loc + 2, 1699 0x8000 | // opcode 1700 ((Val >> 8) & 0x0800) | // J2 1701 ((Val >> 5) & 0x2000) | // J1 1702 ((Val >> 1) & 0x07ff)); // imm11 1703 break; 1704 case R_ARM_THM_CALL: 1705 // R_ARM_THM_CALL is used for BL and BLX instructions, depending on the 1706 // value of bit 0 of Val, we must select a BL or BLX instruction 1707 if ((Val & 1) == 0) { 1708 // Ensure BLX destination is 4-byte aligned. As BLX instruction may 1709 // only be two byte aligned. This must be done before overflow check 1710 Val = alignTo(Val, 4); 1711 } 1712 // Bit 12 is 0 for BLX, 1 for BL 1713 write16le(Loc + 2, (read16le(Loc + 2) & ~0x1000) | (Val & 1) << 12); 1714 // Fall through as rest of encoding is the same as B.W 1715 case R_ARM_THM_JUMP24: 1716 // Encoding B T4, BL T1, BLX T2: Val = S:I1:I2:imm10:imm11:0 1717 // FIXME: Use of I1 and I2 require v6T2ops 1718 checkInt<25>(Val, Type); 1719 write16le(Loc, 1720 0xf000 | // opcode 1721 ((Val >> 14) & 0x0400) | // S 1722 ((Val >> 12) & 0x03ff)); // imm10 1723 write16le(Loc + 2, 1724 (read16le(Loc + 2) & 0xd000) | // opcode 1725 (((~(Val >> 10)) ^ (Val >> 11)) & 0x2000) | // J1 1726 (((~(Val >> 11)) ^ (Val >> 13)) & 0x0800) | // J2 1727 ((Val >> 1) & 0x07ff)); // imm11 1728 break; 1729 case R_ARM_MOVW_ABS_NC: 1730 case R_ARM_MOVW_PREL_NC: 1731 write32le(Loc, (read32le(Loc) & ~0x000f0fff) | ((Val & 0xf000) << 4) | 1732 (Val & 0x0fff)); 1733 break; 1734 case R_ARM_MOVT_ABS: 1735 case R_ARM_MOVT_PREL: 1736 checkInt<32>(Val, Type); 1737 write32le(Loc, (read32le(Loc) & ~0x000f0fff) | 1738 (((Val >> 16) & 0xf000) << 4) | ((Val >> 16) & 0xfff)); 1739 break; 1740 case R_ARM_THM_MOVT_ABS: 1741 case R_ARM_THM_MOVT_PREL: 1742 // Encoding T1: A = imm4:i:imm3:imm8 1743 checkInt<32>(Val, Type); 1744 write16le(Loc, 1745 0xf2c0 | // opcode 1746 ((Val >> 17) & 0x0400) | // i 1747 ((Val >> 28) & 0x000f)); // imm4 1748 write16le(Loc + 2, 1749 (read16le(Loc + 2) & 0x8f00) | // opcode 1750 ((Val >> 12) & 0x7000) | // imm3 1751 ((Val >> 16) & 0x00ff)); // imm8 1752 break; 1753 case R_ARM_THM_MOVW_ABS_NC: 1754 case R_ARM_THM_MOVW_PREL_NC: 1755 // Encoding T3: A = imm4:i:imm3:imm8 1756 write16le(Loc, 1757 0xf240 | // opcode 1758 ((Val >> 1) & 0x0400) | // i 1759 ((Val >> 12) & 0x000f)); // imm4 1760 write16le(Loc + 2, 1761 (read16le(Loc + 2) & 0x8f00) | // opcode 1762 ((Val << 4) & 0x7000) | // imm3 1763 (Val & 0x00ff)); // imm8 1764 break; 1765 default: 1766 fatal("unrecognized reloc " + Twine(Type)); 1767 } 1768 } 1769 1770 uint64_t ARMTargetInfo::getImplicitAddend(const uint8_t *Buf, 1771 uint32_t Type) const { 1772 switch (Type) { 1773 default: 1774 return 0; 1775 case R_ARM_ABS32: 1776 case R_ARM_BASE_PREL: 1777 case R_ARM_GOTOFF32: 1778 case R_ARM_GOT_BREL: 1779 case R_ARM_GOT_PREL: 1780 case R_ARM_REL32: 1781 case R_ARM_TARGET1: 1782 case R_ARM_TLS_GD32: 1783 case R_ARM_TLS_LDM32: 1784 case R_ARM_TLS_LDO32: 1785 case R_ARM_TLS_IE32: 1786 case R_ARM_TLS_LE32: 1787 return SignExtend64<32>(read32le(Buf)); 1788 case R_ARM_PREL31: 1789 return SignExtend64<31>(read32le(Buf)); 1790 case R_ARM_CALL: 1791 case R_ARM_JUMP24: 1792 case R_ARM_PC24: 1793 case R_ARM_PLT32: 1794 return SignExtend64<26>(read32le(Buf) << 2); 1795 case R_ARM_THM_JUMP11: 1796 return SignExtend64<12>(read16le(Buf) << 1); 1797 case R_ARM_THM_JUMP19: { 1798 // Encoding T3: A = S:J2:J1:imm10:imm6:0 1799 uint16_t Hi = read16le(Buf); 1800 uint16_t Lo = read16le(Buf + 2); 1801 return SignExtend64<20>(((Hi & 0x0400) << 10) | // S 1802 ((Lo & 0x0800) << 8) | // J2 1803 ((Lo & 0x2000) << 5) | // J1 1804 ((Hi & 0x003f) << 12) | // imm6 1805 ((Lo & 0x07ff) << 1)); // imm11:0 1806 } 1807 case R_ARM_THM_CALL: 1808 case R_ARM_THM_JUMP24: { 1809 // Encoding B T4, BL T1, BLX T2: A = S:I1:I2:imm10:imm11:0 1810 // I1 = NOT(J1 EOR S), I2 = NOT(J2 EOR S) 1811 // FIXME: I1 and I2 require v6T2ops 1812 uint16_t Hi = read16le(Buf); 1813 uint16_t Lo = read16le(Buf + 2); 1814 return SignExtend64<24>(((Hi & 0x0400) << 14) | // S 1815 (~((Lo ^ (Hi << 3)) << 10) & 0x00800000) | // I1 1816 (~((Lo ^ (Hi << 1)) << 11) & 0x00400000) | // I2 1817 ((Hi & 0x003ff) << 12) | // imm0 1818 ((Lo & 0x007ff) << 1)); // imm11:0 1819 } 1820 // ELF for the ARM Architecture 4.6.1.1 the implicit addend for MOVW and 1821 // MOVT is in the range -32768 <= A < 32768 1822 case R_ARM_MOVW_ABS_NC: 1823 case R_ARM_MOVT_ABS: 1824 case R_ARM_MOVW_PREL_NC: 1825 case R_ARM_MOVT_PREL: { 1826 uint64_t Val = read32le(Buf) & 0x000f0fff; 1827 return SignExtend64<16>(((Val & 0x000f0000) >> 4) | (Val & 0x00fff)); 1828 } 1829 case R_ARM_THM_MOVW_ABS_NC: 1830 case R_ARM_THM_MOVT_ABS: 1831 case R_ARM_THM_MOVW_PREL_NC: 1832 case R_ARM_THM_MOVT_PREL: { 1833 // Encoding T3: A = imm4:i:imm3:imm8 1834 uint16_t Hi = read16le(Buf); 1835 uint16_t Lo = read16le(Buf + 2); 1836 return SignExtend64<16>(((Hi & 0x000f) << 12) | // imm4 1837 ((Hi & 0x0400) << 1) | // i 1838 ((Lo & 0x7000) >> 4) | // imm3 1839 (Lo & 0x00ff)); // imm8 1840 } 1841 } 1842 } 1843 1844 bool ARMTargetInfo::isTlsLocalDynamicRel(uint32_t Type) const { 1845 return Type == R_ARM_TLS_LDO32 || Type == R_ARM_TLS_LDM32; 1846 } 1847 1848 bool ARMTargetInfo::isTlsGlobalDynamicRel(uint32_t Type) const { 1849 return Type == R_ARM_TLS_GD32; 1850 } 1851 1852 bool ARMTargetInfo::isTlsInitialExecRel(uint32_t Type) const { 1853 return Type == R_ARM_TLS_IE32; 1854 } 1855 1856 template <class ELFT> MipsTargetInfo<ELFT>::MipsTargetInfo() { 1857 GotPltHeaderEntriesNum = 2; 1858 PageSize = 65536; 1859 GotEntrySize = sizeof(typename ELFT::uint); 1860 GotPltEntrySize = sizeof(typename ELFT::uint); 1861 PltEntrySize = 16; 1862 PltHeaderSize = 32; 1863 CopyRel = R_MIPS_COPY; 1864 PltRel = R_MIPS_JUMP_SLOT; 1865 NeedsThunks = true; 1866 if (ELFT::Is64Bits) { 1867 RelativeRel = (R_MIPS_64 << 8) | R_MIPS_REL32; 1868 TlsGotRel = R_MIPS_TLS_TPREL64; 1869 TlsModuleIndexRel = R_MIPS_TLS_DTPMOD64; 1870 TlsOffsetRel = R_MIPS_TLS_DTPREL64; 1871 } else { 1872 RelativeRel = R_MIPS_REL32; 1873 TlsGotRel = R_MIPS_TLS_TPREL32; 1874 TlsModuleIndexRel = R_MIPS_TLS_DTPMOD32; 1875 TlsOffsetRel = R_MIPS_TLS_DTPREL32; 1876 } 1877 } 1878 1879 template <class ELFT> 1880 RelExpr MipsTargetInfo<ELFT>::getRelExpr(uint32_t Type, 1881 const SymbolBody &S) const { 1882 if (ELFT::Is64Bits) 1883 // See comment in the calculateMips64RelChain. 1884 Type &= 0xff; 1885 switch (Type) { 1886 default: 1887 return R_ABS; 1888 case R_MIPS_JALR: 1889 return R_HINT; 1890 case R_MIPS_GPREL16: 1891 case R_MIPS_GPREL32: 1892 return R_GOTREL; 1893 case R_MIPS_26: 1894 return R_PLT; 1895 case R_MIPS_HI16: 1896 case R_MIPS_LO16: 1897 case R_MIPS_GOT_OFST: 1898 // MIPS _gp_disp designates offset between start of function and 'gp' 1899 // pointer into GOT. __gnu_local_gp is equal to the current value of 1900 // the 'gp'. Therefore any relocations against them do not require 1901 // dynamic relocation. 1902 if (&S == ElfSym<ELFT>::MipsGpDisp) 1903 return R_PC; 1904 return R_ABS; 1905 case R_MIPS_PC32: 1906 case R_MIPS_PC16: 1907 case R_MIPS_PC19_S2: 1908 case R_MIPS_PC21_S2: 1909 case R_MIPS_PC26_S2: 1910 case R_MIPS_PCHI16: 1911 case R_MIPS_PCLO16: 1912 return R_PC; 1913 case R_MIPS_GOT16: 1914 if (S.isLocal()) 1915 return R_MIPS_GOT_LOCAL_PAGE; 1916 // fallthrough 1917 case R_MIPS_CALL16: 1918 case R_MIPS_CALL_HI16: 1919 case R_MIPS_CALL_LO16: 1920 case R_MIPS_GOT_DISP: 1921 case R_MIPS_GOT_HI16: 1922 case R_MIPS_GOT_LO16: 1923 case R_MIPS_TLS_GOTTPREL: 1924 return R_MIPS_GOT_OFF; 1925 case R_MIPS_GOT_PAGE: 1926 return R_MIPS_GOT_LOCAL_PAGE; 1927 case R_MIPS_TLS_GD: 1928 return R_MIPS_TLSGD; 1929 case R_MIPS_TLS_LDM: 1930 return R_MIPS_TLSLD; 1931 } 1932 } 1933 1934 template <class ELFT> 1935 uint32_t MipsTargetInfo<ELFT>::getDynRel(uint32_t Type) const { 1936 if (Type == R_MIPS_32 || Type == R_MIPS_64) 1937 return RelativeRel; 1938 // Keep it going with a dummy value so that we can find more reloc errors. 1939 errorDynRel(Type); 1940 return R_MIPS_32; 1941 } 1942 1943 template <class ELFT> 1944 bool MipsTargetInfo<ELFT>::isTlsLocalDynamicRel(uint32_t Type) const { 1945 return Type == R_MIPS_TLS_LDM; 1946 } 1947 1948 template <class ELFT> 1949 bool MipsTargetInfo<ELFT>::isTlsGlobalDynamicRel(uint32_t Type) const { 1950 return Type == R_MIPS_TLS_GD; 1951 } 1952 1953 template <class ELFT> 1954 void MipsTargetInfo<ELFT>::writeGotPlt(uint8_t *Buf, const SymbolBody &) const { 1955 write32<ELFT::TargetEndianness>(Buf, Out<ELFT>::Plt->getVA()); 1956 } 1957 1958 template <endianness E, uint8_t BSIZE, uint8_t SHIFT> 1959 static int64_t getPcRelocAddend(const uint8_t *Loc) { 1960 uint32_t Instr = read32<E>(Loc); 1961 uint32_t Mask = 0xffffffff >> (32 - BSIZE); 1962 return SignExtend64<BSIZE + SHIFT>((Instr & Mask) << SHIFT); 1963 } 1964 1965 template <endianness E, uint8_t BSIZE, uint8_t SHIFT> 1966 static void applyMipsPcReloc(uint8_t *Loc, uint32_t Type, uint64_t V) { 1967 uint32_t Mask = 0xffffffff >> (32 - BSIZE); 1968 uint32_t Instr = read32<E>(Loc); 1969 if (SHIFT > 0) 1970 checkAlignment<(1 << SHIFT)>(V, Type); 1971 checkInt<BSIZE + SHIFT>(V, Type); 1972 write32<E>(Loc, (Instr & ~Mask) | ((V >> SHIFT) & Mask)); 1973 } 1974 1975 template <endianness E> 1976 static void writeMipsHi16(uint8_t *Loc, uint64_t V) { 1977 uint32_t Instr = read32<E>(Loc); 1978 uint16_t Res = ((V + 0x8000) >> 16) & 0xffff; 1979 write32<E>(Loc, (Instr & 0xffff0000) | Res); 1980 } 1981 1982 template <endianness E> 1983 static void writeMipsHigher(uint8_t *Loc, uint64_t V) { 1984 uint32_t Instr = read32<E>(Loc); 1985 uint16_t Res = ((V + 0x80008000) >> 32) & 0xffff; 1986 write32<E>(Loc, (Instr & 0xffff0000) | Res); 1987 } 1988 1989 template <endianness E> 1990 static void writeMipsHighest(uint8_t *Loc, uint64_t V) { 1991 uint32_t Instr = read32<E>(Loc); 1992 uint16_t Res = ((V + 0x800080008000) >> 48) & 0xffff; 1993 write32<E>(Loc, (Instr & 0xffff0000) | Res); 1994 } 1995 1996 template <endianness E> 1997 static void writeMipsLo16(uint8_t *Loc, uint64_t V) { 1998 uint32_t Instr = read32<E>(Loc); 1999 write32<E>(Loc, (Instr & 0xffff0000) | (V & 0xffff)); 2000 } 2001 2002 template <class ELFT> static bool isMipsR6() { 2003 const auto &FirstObj = cast<ELFFileBase<ELFT>>(*Config->FirstElf); 2004 uint32_t Arch = FirstObj.getObj().getHeader()->e_flags & EF_MIPS_ARCH; 2005 return Arch == EF_MIPS_ARCH_32R6 || Arch == EF_MIPS_ARCH_64R6; 2006 } 2007 2008 template <class ELFT> 2009 void MipsTargetInfo<ELFT>::writePltHeader(uint8_t *Buf) const { 2010 const endianness E = ELFT::TargetEndianness; 2011 write32<E>(Buf, 0x3c1c0000); // lui $28, %hi(&GOTPLT[0]) 2012 write32<E>(Buf + 4, 0x8f990000); // lw $25, %lo(&GOTPLT[0])($28) 2013 write32<E>(Buf + 8, 0x279c0000); // addiu $28, $28, %lo(&GOTPLT[0]) 2014 write32<E>(Buf + 12, 0x031cc023); // subu $24, $24, $28 2015 write32<E>(Buf + 16, 0x03e07825); // move $15, $31 2016 write32<E>(Buf + 20, 0x0018c082); // srl $24, $24, 2 2017 write32<E>(Buf + 24, 0x0320f809); // jalr $25 2018 write32<E>(Buf + 28, 0x2718fffe); // subu $24, $24, 2 2019 uint64_t Got = Out<ELFT>::GotPlt->getVA(); 2020 writeMipsHi16<E>(Buf, Got); 2021 writeMipsLo16<E>(Buf + 4, Got); 2022 writeMipsLo16<E>(Buf + 8, Got); 2023 } 2024 2025 template <class ELFT> 2026 void MipsTargetInfo<ELFT>::writePlt(uint8_t *Buf, uint64_t GotEntryAddr, 2027 uint64_t PltEntryAddr, int32_t Index, 2028 unsigned RelOff) const { 2029 const endianness E = ELFT::TargetEndianness; 2030 write32<E>(Buf, 0x3c0f0000); // lui $15, %hi(.got.plt entry) 2031 write32<E>(Buf + 4, 0x8df90000); // l[wd] $25, %lo(.got.plt entry)($15) 2032 // jr $25 2033 write32<E>(Buf + 8, isMipsR6<ELFT>() ? 0x03200009 : 0x03200008); 2034 write32<E>(Buf + 12, 0x25f80000); // addiu $24, $15, %lo(.got.plt entry) 2035 writeMipsHi16<E>(Buf, GotEntryAddr); 2036 writeMipsLo16<E>(Buf + 4, GotEntryAddr); 2037 writeMipsLo16<E>(Buf + 12, GotEntryAddr); 2038 } 2039 2040 template <class ELFT> 2041 RelExpr MipsTargetInfo<ELFT>::getThunkExpr(RelExpr Expr, uint32_t Type, 2042 const InputFile &File, 2043 const SymbolBody &S) const { 2044 // Any MIPS PIC code function is invoked with its address in register $t9. 2045 // So if we have a branch instruction from non-PIC code to the PIC one 2046 // we cannot make the jump directly and need to create a small stubs 2047 // to save the target function address. 2048 // See page 3-38 ftp://www.linux-mips.org/pub/linux/mips/doc/ABI/mipsabi.pdf 2049 if (Type != R_MIPS_26) 2050 return Expr; 2051 auto *F = dyn_cast<ELFFileBase<ELFT>>(&File); 2052 if (!F) 2053 return Expr; 2054 // If current file has PIC code, LA25 stub is not required. 2055 if (F->getObj().getHeader()->e_flags & EF_MIPS_PIC) 2056 return Expr; 2057 auto *D = dyn_cast<DefinedRegular<ELFT>>(&S); 2058 if (!D || !D->Section) 2059 return Expr; 2060 // LA25 is required if target file has PIC code 2061 // or target symbol is a PIC symbol. 2062 const ELFFile<ELFT> &DefFile = D->Section->getFile()->getObj(); 2063 bool PicFile = DefFile.getHeader()->e_flags & EF_MIPS_PIC; 2064 bool PicSym = (D->StOther & STO_MIPS_MIPS16) == STO_MIPS_PIC; 2065 return (PicFile || PicSym) ? R_THUNK_ABS : Expr; 2066 } 2067 2068 template <class ELFT> 2069 uint64_t MipsTargetInfo<ELFT>::getImplicitAddend(const uint8_t *Buf, 2070 uint32_t Type) const { 2071 const endianness E = ELFT::TargetEndianness; 2072 switch (Type) { 2073 default: 2074 return 0; 2075 case R_MIPS_32: 2076 case R_MIPS_GPREL32: 2077 case R_MIPS_TLS_DTPREL32: 2078 case R_MIPS_TLS_TPREL32: 2079 return read32<E>(Buf); 2080 case R_MIPS_26: 2081 // FIXME (simon): If the relocation target symbol is not a PLT entry 2082 // we should use another expression for calculation: 2083 // ((A << 2) | (P & 0xf0000000)) >> 2 2084 return SignExtend64<28>((read32<E>(Buf) & 0x3ffffff) << 2); 2085 case R_MIPS_GPREL16: 2086 case R_MIPS_LO16: 2087 case R_MIPS_PCLO16: 2088 case R_MIPS_TLS_DTPREL_HI16: 2089 case R_MIPS_TLS_DTPREL_LO16: 2090 case R_MIPS_TLS_TPREL_HI16: 2091 case R_MIPS_TLS_TPREL_LO16: 2092 return SignExtend64<16>(read32<E>(Buf)); 2093 case R_MIPS_PC16: 2094 return getPcRelocAddend<E, 16, 2>(Buf); 2095 case R_MIPS_PC19_S2: 2096 return getPcRelocAddend<E, 19, 2>(Buf); 2097 case R_MIPS_PC21_S2: 2098 return getPcRelocAddend<E, 21, 2>(Buf); 2099 case R_MIPS_PC26_S2: 2100 return getPcRelocAddend<E, 26, 2>(Buf); 2101 case R_MIPS_PC32: 2102 return getPcRelocAddend<E, 32, 0>(Buf); 2103 } 2104 } 2105 2106 static std::pair<uint32_t, uint64_t> calculateMips64RelChain(uint32_t Type, 2107 uint64_t Val) { 2108 // MIPS N64 ABI packs multiple relocations into the single relocation 2109 // record. In general, all up to three relocations can have arbitrary 2110 // types. In fact, Clang and GCC uses only a few combinations. For now, 2111 // we support two of them. That is allow to pass at least all LLVM 2112 // test suite cases. 2113 // <any relocation> / R_MIPS_SUB / R_MIPS_HI16 | R_MIPS_LO16 2114 // <any relocation> / R_MIPS_64 / R_MIPS_NONE 2115 // The first relocation is a 'real' relocation which is calculated 2116 // using the corresponding symbol's value. The second and the third 2117 // relocations used to modify result of the first one: extend it to 2118 // 64-bit, extract high or low part etc. For details, see part 2.9 Relocation 2119 // at the https://dmz-portal.mips.com/mw/images/8/82/007-4658-001.pdf 2120 uint32_t Type2 = (Type >> 8) & 0xff; 2121 uint32_t Type3 = (Type >> 16) & 0xff; 2122 if (Type2 == R_MIPS_NONE && Type3 == R_MIPS_NONE) 2123 return std::make_pair(Type, Val); 2124 if (Type2 == R_MIPS_64 && Type3 == R_MIPS_NONE) 2125 return std::make_pair(Type2, Val); 2126 if (Type2 == R_MIPS_SUB && (Type3 == R_MIPS_HI16 || Type3 == R_MIPS_LO16)) 2127 return std::make_pair(Type3, -Val); 2128 error("unsupported relocations combination " + Twine(Type)); 2129 return std::make_pair(Type & 0xff, Val); 2130 } 2131 2132 template <class ELFT> 2133 void MipsTargetInfo<ELFT>::relocateOne(uint8_t *Loc, uint32_t Type, 2134 uint64_t Val) const { 2135 const endianness E = ELFT::TargetEndianness; 2136 // Thread pointer and DRP offsets from the start of TLS data area. 2137 // https://www.linux-mips.org/wiki/NPTL 2138 if (Type == R_MIPS_TLS_DTPREL_HI16 || Type == R_MIPS_TLS_DTPREL_LO16 || 2139 Type == R_MIPS_TLS_DTPREL32 || Type == R_MIPS_TLS_DTPREL64) 2140 Val -= 0x8000; 2141 else if (Type == R_MIPS_TLS_TPREL_HI16 || Type == R_MIPS_TLS_TPREL_LO16 || 2142 Type == R_MIPS_TLS_TPREL32 || Type == R_MIPS_TLS_TPREL64) 2143 Val -= 0x7000; 2144 if (ELFT::Is64Bits) 2145 std::tie(Type, Val) = calculateMips64RelChain(Type, Val); 2146 switch (Type) { 2147 case R_MIPS_32: 2148 case R_MIPS_GPREL32: 2149 case R_MIPS_TLS_DTPREL32: 2150 case R_MIPS_TLS_TPREL32: 2151 write32<E>(Loc, Val); 2152 break; 2153 case R_MIPS_64: 2154 case R_MIPS_TLS_DTPREL64: 2155 case R_MIPS_TLS_TPREL64: 2156 write64<E>(Loc, Val); 2157 break; 2158 case R_MIPS_26: 2159 write32<E>(Loc, (read32<E>(Loc) & ~0x3ffffff) | ((Val >> 2) & 0x3ffffff)); 2160 break; 2161 case R_MIPS_GOT_DISP: 2162 case R_MIPS_GOT_PAGE: 2163 case R_MIPS_GOT16: 2164 case R_MIPS_GPREL16: 2165 case R_MIPS_TLS_GD: 2166 case R_MIPS_TLS_LDM: 2167 checkInt<16>(Val, Type); 2168 // fallthrough 2169 case R_MIPS_CALL16: 2170 case R_MIPS_CALL_LO16: 2171 case R_MIPS_GOT_LO16: 2172 case R_MIPS_GOT_OFST: 2173 case R_MIPS_LO16: 2174 case R_MIPS_PCLO16: 2175 case R_MIPS_TLS_DTPREL_LO16: 2176 case R_MIPS_TLS_GOTTPREL: 2177 case R_MIPS_TLS_TPREL_LO16: 2178 writeMipsLo16<E>(Loc, Val); 2179 break; 2180 case R_MIPS_CALL_HI16: 2181 case R_MIPS_GOT_HI16: 2182 case R_MIPS_HI16: 2183 case R_MIPS_PCHI16: 2184 case R_MIPS_TLS_DTPREL_HI16: 2185 case R_MIPS_TLS_TPREL_HI16: 2186 writeMipsHi16<E>(Loc, Val); 2187 break; 2188 case R_MIPS_HIGHER: 2189 writeMipsHigher<E>(Loc, Val); 2190 break; 2191 case R_MIPS_HIGHEST: 2192 writeMipsHighest<E>(Loc, Val); 2193 break; 2194 case R_MIPS_JALR: 2195 // Ignore this optimization relocation for now 2196 break; 2197 case R_MIPS_PC16: 2198 applyMipsPcReloc<E, 16, 2>(Loc, Type, Val); 2199 break; 2200 case R_MIPS_PC19_S2: 2201 applyMipsPcReloc<E, 19, 2>(Loc, Type, Val); 2202 break; 2203 case R_MIPS_PC21_S2: 2204 applyMipsPcReloc<E, 21, 2>(Loc, Type, Val); 2205 break; 2206 case R_MIPS_PC26_S2: 2207 applyMipsPcReloc<E, 26, 2>(Loc, Type, Val); 2208 break; 2209 case R_MIPS_PC32: 2210 applyMipsPcReloc<E, 32, 0>(Loc, Type, Val); 2211 break; 2212 default: 2213 fatal("unrecognized reloc " + Twine(Type)); 2214 } 2215 } 2216 2217 template <class ELFT> 2218 bool MipsTargetInfo<ELFT>::usesOnlyLowPageBits(uint32_t Type) const { 2219 return Type == R_MIPS_LO16 || Type == R_MIPS_GOT_OFST; 2220 } 2221 } 2222 } 2223