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 std::string toString(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 " + toString(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 " + toString(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 " + toString(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 " + toString(Type)); 76 } 77 78 static void errorDynRel(uint32_t Type) { 79 error("relocation " + toString(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 // Align to the large page size (known as a superpage or huge page). 562 // FreeBSD automatically promotes large, superpage-aligned allocations. 563 DefaultImageBase = 0x200000; 564 } 565 566 template <class ELFT> 567 RelExpr X86_64TargetInfo<ELFT>::getRelExpr(uint32_t Type, 568 const SymbolBody &S) const { 569 switch (Type) { 570 default: 571 return R_ABS; 572 case R_X86_64_TPOFF32: 573 return R_TLS; 574 case R_X86_64_TLSLD: 575 return R_TLSLD_PC; 576 case R_X86_64_TLSGD: 577 return R_TLSGD_PC; 578 case R_X86_64_SIZE32: 579 case R_X86_64_SIZE64: 580 return R_SIZE; 581 case R_X86_64_PLT32: 582 return R_PLT_PC; 583 case R_X86_64_PC32: 584 case R_X86_64_PC64: 585 return R_PC; 586 case R_X86_64_GOT32: 587 return R_GOT_FROM_END; 588 case R_X86_64_GOTPCREL: 589 case R_X86_64_GOTPCRELX: 590 case R_X86_64_REX_GOTPCRELX: 591 case R_X86_64_GOTTPOFF: 592 return R_GOT_PC; 593 } 594 } 595 596 template <class ELFT> 597 void X86_64TargetInfo<ELFT>::writeGotPltHeader(uint8_t *Buf) const { 598 // The first entry holds the value of _DYNAMIC. It is not clear why that is 599 // required, but it is documented in the psabi and the glibc dynamic linker 600 // seems to use it (note that this is relevant for linking ld.so, not any 601 // other program). 602 write64le(Buf, In<ELFT>::Dynamic->getVA()); 603 } 604 605 template <class ELFT> 606 void X86_64TargetInfo<ELFT>::writeGotPlt(uint8_t *Buf, 607 const SymbolBody &S) const { 608 // See comments in X86TargetInfo::writeGotPlt. 609 write32le(Buf, S.getPltVA<ELFT>() + 6); 610 } 611 612 template <class ELFT> 613 void X86_64TargetInfo<ELFT>::writePltHeader(uint8_t *Buf) const { 614 const uint8_t PltData[] = { 615 0xff, 0x35, 0x00, 0x00, 0x00, 0x00, // pushq GOT+8(%rip) 616 0xff, 0x25, 0x00, 0x00, 0x00, 0x00, // jmp *GOT+16(%rip) 617 0x0f, 0x1f, 0x40, 0x00 // nopl 0x0(rax) 618 }; 619 memcpy(Buf, PltData, sizeof(PltData)); 620 uint64_t Got = In<ELFT>::GotPlt->getVA(); 621 uint64_t Plt = In<ELFT>::Plt->getVA(); 622 write32le(Buf + 2, Got - Plt + 2); // GOT+8 623 write32le(Buf + 8, Got - Plt + 4); // GOT+16 624 } 625 626 template <class ELFT> 627 void X86_64TargetInfo<ELFT>::writePlt(uint8_t *Buf, uint64_t GotEntryAddr, 628 uint64_t PltEntryAddr, int32_t Index, 629 unsigned RelOff) const { 630 const uint8_t Inst[] = { 631 0xff, 0x25, 0x00, 0x00, 0x00, 0x00, // jmpq *got(%rip) 632 0x68, 0x00, 0x00, 0x00, 0x00, // pushq <relocation index> 633 0xe9, 0x00, 0x00, 0x00, 0x00 // jmpq plt[0] 634 }; 635 memcpy(Buf, Inst, sizeof(Inst)); 636 637 write32le(Buf + 2, GotEntryAddr - PltEntryAddr - 6); 638 write32le(Buf + 7, Index); 639 write32le(Buf + 12, -Index * PltEntrySize - PltHeaderSize - 16); 640 } 641 642 template <class ELFT> 643 uint32_t X86_64TargetInfo<ELFT>::getDynRel(uint32_t Type) const { 644 if (Type == R_X86_64_PC32 || Type == R_X86_64_32) 645 errorDynRel(Type); 646 return Type; 647 } 648 649 template <class ELFT> 650 bool X86_64TargetInfo<ELFT>::isTlsInitialExecRel(uint32_t Type) const { 651 return Type == R_X86_64_GOTTPOFF; 652 } 653 654 template <class ELFT> 655 bool X86_64TargetInfo<ELFT>::isTlsGlobalDynamicRel(uint32_t Type) const { 656 return Type == R_X86_64_TLSGD; 657 } 658 659 template <class ELFT> 660 bool X86_64TargetInfo<ELFT>::isTlsLocalDynamicRel(uint32_t Type) const { 661 return Type == R_X86_64_DTPOFF32 || Type == R_X86_64_DTPOFF64 || 662 Type == R_X86_64_TLSLD; 663 } 664 665 template <class ELFT> 666 void X86_64TargetInfo<ELFT>::relaxTlsGdToLe(uint8_t *Loc, uint32_t Type, 667 uint64_t Val) const { 668 // Convert 669 // .byte 0x66 670 // leaq x@tlsgd(%rip), %rdi 671 // .word 0x6666 672 // rex64 673 // call __tls_get_addr@plt 674 // to 675 // mov %fs:0x0,%rax 676 // lea x@tpoff,%rax 677 const uint8_t Inst[] = { 678 0x64, 0x48, 0x8b, 0x04, 0x25, 0x00, 0x00, 0x00, 0x00, // mov %fs:0x0,%rax 679 0x48, 0x8d, 0x80, 0x00, 0x00, 0x00, 0x00 // lea x@tpoff,%rax 680 }; 681 memcpy(Loc - 4, Inst, sizeof(Inst)); 682 // The original code used a pc relative relocation and so we have to 683 // compensate for the -4 in had in the addend. 684 relocateOne(Loc + 8, R_X86_64_TPOFF32, Val + 4); 685 } 686 687 template <class ELFT> 688 void X86_64TargetInfo<ELFT>::relaxTlsGdToIe(uint8_t *Loc, uint32_t Type, 689 uint64_t Val) const { 690 // Convert 691 // .byte 0x66 692 // leaq x@tlsgd(%rip), %rdi 693 // .word 0x6666 694 // rex64 695 // call __tls_get_addr@plt 696 // to 697 // mov %fs:0x0,%rax 698 // addq x@tpoff,%rax 699 const uint8_t Inst[] = { 700 0x64, 0x48, 0x8b, 0x04, 0x25, 0x00, 0x00, 0x00, 0x00, // mov %fs:0x0,%rax 701 0x48, 0x03, 0x05, 0x00, 0x00, 0x00, 0x00 // addq x@tpoff,%rax 702 }; 703 memcpy(Loc - 4, Inst, sizeof(Inst)); 704 // Both code sequences are PC relatives, but since we are moving the constant 705 // forward by 8 bytes we have to subtract the value by 8. 706 relocateOne(Loc + 8, R_X86_64_PC32, Val - 8); 707 } 708 709 // In some conditions, R_X86_64_GOTTPOFF relocation can be optimized to 710 // R_X86_64_TPOFF32 so that it does not use GOT. 711 template <class ELFT> 712 void X86_64TargetInfo<ELFT>::relaxTlsIeToLe(uint8_t *Loc, uint32_t Type, 713 uint64_t Val) const { 714 uint8_t *Inst = Loc - 3; 715 uint8_t Reg = Loc[-1] >> 3; 716 uint8_t *RegSlot = Loc - 1; 717 718 // Note that ADD with RSP or R12 is converted to ADD instead of LEA 719 // because LEA with these registers needs 4 bytes to encode and thus 720 // wouldn't fit the space. 721 722 if (memcmp(Inst, "\x48\x03\x25", 3) == 0) { 723 // "addq foo@gottpoff(%rip),%rsp" -> "addq $foo,%rsp" 724 memcpy(Inst, "\x48\x81\xc4", 3); 725 } else if (memcmp(Inst, "\x4c\x03\x25", 3) == 0) { 726 // "addq foo@gottpoff(%rip),%r12" -> "addq $foo,%r12" 727 memcpy(Inst, "\x49\x81\xc4", 3); 728 } else if (memcmp(Inst, "\x4c\x03", 2) == 0) { 729 // "addq foo@gottpoff(%rip),%r[8-15]" -> "leaq foo(%r[8-15]),%r[8-15]" 730 memcpy(Inst, "\x4d\x8d", 2); 731 *RegSlot = 0x80 | (Reg << 3) | Reg; 732 } else if (memcmp(Inst, "\x48\x03", 2) == 0) { 733 // "addq foo@gottpoff(%rip),%reg -> "leaq foo(%reg),%reg" 734 memcpy(Inst, "\x48\x8d", 2); 735 *RegSlot = 0x80 | (Reg << 3) | Reg; 736 } else if (memcmp(Inst, "\x4c\x8b", 2) == 0) { 737 // "movq foo@gottpoff(%rip),%r[8-15]" -> "movq $foo,%r[8-15]" 738 memcpy(Inst, "\x49\xc7", 2); 739 *RegSlot = 0xc0 | Reg; 740 } else if (memcmp(Inst, "\x48\x8b", 2) == 0) { 741 // "movq foo@gottpoff(%rip),%reg" -> "movq $foo,%reg" 742 memcpy(Inst, "\x48\xc7", 2); 743 *RegSlot = 0xc0 | Reg; 744 } else { 745 fatal("R_X86_64_GOTTPOFF must be used in MOVQ or ADDQ instructions only"); 746 } 747 748 // The original code used a PC relative relocation. 749 // Need to compensate for the -4 it had in the addend. 750 relocateOne(Loc, R_X86_64_TPOFF32, Val + 4); 751 } 752 753 template <class ELFT> 754 void X86_64TargetInfo<ELFT>::relaxTlsLdToLe(uint8_t *Loc, uint32_t Type, 755 uint64_t Val) const { 756 // Convert 757 // leaq bar@tlsld(%rip), %rdi 758 // callq __tls_get_addr@PLT 759 // leaq bar@dtpoff(%rax), %rcx 760 // to 761 // .word 0x6666 762 // .byte 0x66 763 // mov %fs:0,%rax 764 // leaq bar@tpoff(%rax), %rcx 765 if (Type == R_X86_64_DTPOFF64) { 766 write64le(Loc, Val); 767 return; 768 } 769 if (Type == R_X86_64_DTPOFF32) { 770 relocateOne(Loc, R_X86_64_TPOFF32, Val); 771 return; 772 } 773 774 const uint8_t Inst[] = { 775 0x66, 0x66, // .word 0x6666 776 0x66, // .byte 0x66 777 0x64, 0x48, 0x8b, 0x04, 0x25, 0x00, 0x00, 0x00, 0x00 // mov %fs:0,%rax 778 }; 779 memcpy(Loc - 3, Inst, sizeof(Inst)); 780 } 781 782 template <class ELFT> 783 void X86_64TargetInfo<ELFT>::relocateOne(uint8_t *Loc, uint32_t Type, 784 uint64_t Val) const { 785 switch (Type) { 786 case R_X86_64_32: 787 checkUInt<32>(Val, Type); 788 write32le(Loc, Val); 789 break; 790 case R_X86_64_32S: 791 case R_X86_64_TPOFF32: 792 case R_X86_64_GOT32: 793 case R_X86_64_GOTPCREL: 794 case R_X86_64_GOTPCRELX: 795 case R_X86_64_REX_GOTPCRELX: 796 case R_X86_64_PC32: 797 case R_X86_64_GOTTPOFF: 798 case R_X86_64_PLT32: 799 case R_X86_64_TLSGD: 800 case R_X86_64_TLSLD: 801 case R_X86_64_DTPOFF32: 802 case R_X86_64_SIZE32: 803 checkInt<32>(Val, Type); 804 write32le(Loc, Val); 805 break; 806 case R_X86_64_64: 807 case R_X86_64_DTPOFF64: 808 case R_X86_64_SIZE64: 809 case R_X86_64_PC64: 810 write64le(Loc, Val); 811 break; 812 default: 813 fatal("unrecognized reloc " + Twine(Type)); 814 } 815 } 816 817 template <class ELFT> 818 RelExpr X86_64TargetInfo<ELFT>::adjustRelaxExpr(uint32_t Type, 819 const uint8_t *Data, 820 RelExpr RelExpr) const { 821 if (Type != R_X86_64_GOTPCRELX && Type != R_X86_64_REX_GOTPCRELX) 822 return RelExpr; 823 const uint8_t Op = Data[-2]; 824 const uint8_t ModRm = Data[-1]; 825 // FIXME: When PIC is disabled and foo is defined locally in the 826 // lower 32 bit address space, memory operand in mov can be converted into 827 // immediate operand. Otherwise, mov must be changed to lea. We support only 828 // latter relaxation at this moment. 829 if (Op == 0x8b) 830 return R_RELAX_GOT_PC; 831 // Relax call and jmp. 832 if (Op == 0xff && (ModRm == 0x15 || ModRm == 0x25)) 833 return R_RELAX_GOT_PC; 834 835 // Relaxation of test, adc, add, and, cmp, or, sbb, sub, xor. 836 // If PIC then no relaxation is available. 837 // We also don't relax test/binop instructions without REX byte, 838 // they are 32bit operations and not common to have. 839 assert(Type == R_X86_64_REX_GOTPCRELX); 840 return Config->Pic ? RelExpr : R_RELAX_GOT_PC_NOPIC; 841 } 842 843 // A subset of relaxations can only be applied for no-PIC. This method 844 // handles such relaxations. Instructions encoding information was taken from: 845 // "Intel 64 and IA-32 Architectures Software Developer's Manual V2" 846 // (http://www.intel.com/content/dam/www/public/us/en/documents/manuals/ 847 // 64-ia-32-architectures-software-developer-instruction-set-reference-manual-325383.pdf) 848 template <class ELFT> 849 void X86_64TargetInfo<ELFT>::relaxGotNoPic(uint8_t *Loc, uint64_t Val, 850 uint8_t Op, uint8_t ModRm) const { 851 const uint8_t Rex = Loc[-3]; 852 // Convert "test %reg, foo@GOTPCREL(%rip)" to "test $foo, %reg". 853 if (Op == 0x85) { 854 // See "TEST-Logical Compare" (4-428 Vol. 2B), 855 // TEST r/m64, r64 uses "full" ModR / M byte (no opcode extension). 856 857 // ModR/M byte has form XX YYY ZZZ, where 858 // YYY is MODRM.reg(register 2), ZZZ is MODRM.rm(register 1). 859 // XX has different meanings: 860 // 00: The operand's memory address is in reg1. 861 // 01: The operand's memory address is reg1 + a byte-sized displacement. 862 // 10: The operand's memory address is reg1 + a word-sized displacement. 863 // 11: The operand is reg1 itself. 864 // If an instruction requires only one operand, the unused reg2 field 865 // holds extra opcode bits rather than a register code 866 // 0xC0 == 11 000 000 binary. 867 // 0x38 == 00 111 000 binary. 868 // We transfer reg2 to reg1 here as operand. 869 // See "2.1.3 ModR/M and SIB Bytes" (Vol. 2A 2-3). 870 Loc[-1] = 0xc0 | (ModRm & 0x38) >> 3; // ModR/M byte. 871 872 // Change opcode from TEST r/m64, r64 to TEST r/m64, imm32 873 // See "TEST-Logical Compare" (4-428 Vol. 2B). 874 Loc[-2] = 0xf7; 875 876 // Move R bit to the B bit in REX byte. 877 // REX byte is encoded as 0100WRXB, where 878 // 0100 is 4bit fixed pattern. 879 // REX.W When 1, a 64-bit operand size is used. Otherwise, when 0, the 880 // default operand size is used (which is 32-bit for most but not all 881 // instructions). 882 // REX.R This 1-bit value is an extension to the MODRM.reg field. 883 // REX.X This 1-bit value is an extension to the SIB.index field. 884 // REX.B This 1-bit value is an extension to the MODRM.rm field or the 885 // SIB.base field. 886 // See "2.2.1.2 More on REX Prefix Fields " (2-8 Vol. 2A). 887 Loc[-3] = (Rex & ~0x4) | (Rex & 0x4) >> 2; 888 relocateOne(Loc, R_X86_64_PC32, Val); 889 return; 890 } 891 892 // If we are here then we need to relax the adc, add, and, cmp, or, sbb, sub 893 // or xor operations. 894 895 // Convert "binop foo@GOTPCREL(%rip), %reg" to "binop $foo, %reg". 896 // Logic is close to one for test instruction above, but we also 897 // write opcode extension here, see below for details. 898 Loc[-1] = 0xc0 | (ModRm & 0x38) >> 3 | (Op & 0x3c); // ModR/M byte. 899 900 // Primary opcode is 0x81, opcode extension is one of: 901 // 000b = ADD, 001b is OR, 010b is ADC, 011b is SBB, 902 // 100b is AND, 101b is SUB, 110b is XOR, 111b is CMP. 903 // This value was wrote to MODRM.reg in a line above. 904 // See "3.2 INSTRUCTIONS (A-M)" (Vol. 2A 3-15), 905 // "INSTRUCTION SET REFERENCE, N-Z" (Vol. 2B 4-1) for 906 // descriptions about each operation. 907 Loc[-2] = 0x81; 908 Loc[-3] = (Rex & ~0x4) | (Rex & 0x4) >> 2; 909 relocateOne(Loc, R_X86_64_PC32, Val); 910 } 911 912 template <class ELFT> 913 void X86_64TargetInfo<ELFT>::relaxGot(uint8_t *Loc, uint64_t Val) const { 914 const uint8_t Op = Loc[-2]; 915 const uint8_t ModRm = Loc[-1]; 916 917 // Convert "mov foo@GOTPCREL(%rip),%reg" to "lea foo(%rip),%reg". 918 if (Op == 0x8b) { 919 Loc[-2] = 0x8d; 920 relocateOne(Loc, R_X86_64_PC32, Val); 921 return; 922 } 923 924 if (Op != 0xff) { 925 // We are relaxing a rip relative to an absolute, so compensate 926 // for the old -4 addend. 927 assert(!Config->Pic); 928 relaxGotNoPic(Loc, Val + 4, Op, ModRm); 929 return; 930 } 931 932 // Convert call/jmp instructions. 933 if (ModRm == 0x15) { 934 // ABI says we can convert "call *foo@GOTPCREL(%rip)" to "nop; call foo". 935 // Instead we convert to "addr32 call foo" where addr32 is an instruction 936 // prefix. That makes result expression to be a single instruction. 937 Loc[-2] = 0x67; // addr32 prefix 938 Loc[-1] = 0xe8; // call 939 relocateOne(Loc, R_X86_64_PC32, Val); 940 return; 941 } 942 943 // Convert "jmp *foo@GOTPCREL(%rip)" to "jmp foo; nop". 944 // jmp doesn't return, so it is fine to use nop here, it is just a stub. 945 assert(ModRm == 0x25); 946 Loc[-2] = 0xe9; // jmp 947 Loc[3] = 0x90; // nop 948 relocateOne(Loc - 1, R_X86_64_PC32, Val + 1); 949 } 950 951 // Relocation masks following the #lo(value), #hi(value), #ha(value), 952 // #higher(value), #highera(value), #highest(value), and #highesta(value) 953 // macros defined in section 4.5.1. Relocation Types of the PPC-elf64abi 954 // document. 955 static uint16_t applyPPCLo(uint64_t V) { return V; } 956 static uint16_t applyPPCHi(uint64_t V) { return V >> 16; } 957 static uint16_t applyPPCHa(uint64_t V) { return (V + 0x8000) >> 16; } 958 static uint16_t applyPPCHigher(uint64_t V) { return V >> 32; } 959 static uint16_t applyPPCHighera(uint64_t V) { return (V + 0x8000) >> 32; } 960 static uint16_t applyPPCHighest(uint64_t V) { return V >> 48; } 961 static uint16_t applyPPCHighesta(uint64_t V) { return (V + 0x8000) >> 48; } 962 963 PPCTargetInfo::PPCTargetInfo() {} 964 965 void PPCTargetInfo::relocateOne(uint8_t *Loc, uint32_t Type, 966 uint64_t Val) const { 967 switch (Type) { 968 case R_PPC_ADDR16_HA: 969 write16be(Loc, applyPPCHa(Val)); 970 break; 971 case R_PPC_ADDR16_LO: 972 write16be(Loc, applyPPCLo(Val)); 973 break; 974 case R_PPC_ADDR32: 975 case R_PPC_REL32: 976 write32be(Loc, Val); 977 break; 978 case R_PPC_REL24: 979 or32be(Loc, Val & 0x3FFFFFC); 980 break; 981 default: 982 fatal("unrecognized reloc " + Twine(Type)); 983 } 984 } 985 986 RelExpr PPCTargetInfo::getRelExpr(uint32_t Type, const SymbolBody &S) const { 987 switch (Type) { 988 case R_PPC_REL24: 989 case R_PPC_REL32: 990 return R_PC; 991 default: 992 return R_ABS; 993 } 994 } 995 996 PPC64TargetInfo::PPC64TargetInfo() { 997 PltRel = GotRel = R_PPC64_GLOB_DAT; 998 RelativeRel = R_PPC64_RELATIVE; 999 GotEntrySize = 8; 1000 GotPltEntrySize = 8; 1001 PltEntrySize = 32; 1002 PltHeaderSize = 0; 1003 1004 // We need 64K pages (at least under glibc/Linux, the loader won't 1005 // set different permissions on a finer granularity than that). 1006 MaxPageSize = 65536; 1007 1008 // The PPC64 ELF ABI v1 spec, says: 1009 // 1010 // It is normally desirable to put segments with different characteristics 1011 // in separate 256 Mbyte portions of the address space, to give the 1012 // operating system full paging flexibility in the 64-bit address space. 1013 // 1014 // And because the lowest non-zero 256M boundary is 0x10000000, PPC64 linkers 1015 // use 0x10000000 as the starting address. 1016 DefaultImageBase = 0x10000000; 1017 } 1018 1019 static uint64_t PPC64TocOffset = 0x8000; 1020 1021 uint64_t getPPC64TocBase() { 1022 // The TOC consists of sections .got, .toc, .tocbss, .plt in that order. The 1023 // TOC starts where the first of these sections starts. We always create a 1024 // .got when we see a relocation that uses it, so for us the start is always 1025 // the .got. 1026 uint64_t TocVA = In<ELF64BE>::Got->getVA(); 1027 1028 // Per the ppc64-elf-linux ABI, The TOC base is TOC value plus 0x8000 1029 // thus permitting a full 64 Kbytes segment. Note that the glibc startup 1030 // code (crt1.o) assumes that you can get from the TOC base to the 1031 // start of the .toc section with only a single (signed) 16-bit relocation. 1032 return TocVA + PPC64TocOffset; 1033 } 1034 1035 RelExpr PPC64TargetInfo::getRelExpr(uint32_t Type, const SymbolBody &S) const { 1036 switch (Type) { 1037 default: 1038 return R_ABS; 1039 case R_PPC64_TOC16: 1040 case R_PPC64_TOC16_DS: 1041 case R_PPC64_TOC16_HA: 1042 case R_PPC64_TOC16_HI: 1043 case R_PPC64_TOC16_LO: 1044 case R_PPC64_TOC16_LO_DS: 1045 return R_GOTREL; 1046 case R_PPC64_TOC: 1047 return R_PPC_TOC; 1048 case R_PPC64_REL24: 1049 return R_PPC_PLT_OPD; 1050 } 1051 } 1052 1053 void PPC64TargetInfo::writePlt(uint8_t *Buf, uint64_t GotEntryAddr, 1054 uint64_t PltEntryAddr, int32_t Index, 1055 unsigned RelOff) const { 1056 uint64_t Off = GotEntryAddr - getPPC64TocBase(); 1057 1058 // FIXME: What we should do, in theory, is get the offset of the function 1059 // descriptor in the .opd section, and use that as the offset from %r2 (the 1060 // TOC-base pointer). Instead, we have the GOT-entry offset, and that will 1061 // be a pointer to the function descriptor in the .opd section. Using 1062 // this scheme is simpler, but requires an extra indirection per PLT dispatch. 1063 1064 write32be(Buf, 0xf8410028); // std %r2, 40(%r1) 1065 write32be(Buf + 4, 0x3d620000 | applyPPCHa(Off)); // addis %r11, %r2, X@ha 1066 write32be(Buf + 8, 0xe98b0000 | applyPPCLo(Off)); // ld %r12, X@l(%r11) 1067 write32be(Buf + 12, 0xe96c0000); // ld %r11,0(%r12) 1068 write32be(Buf + 16, 0x7d6903a6); // mtctr %r11 1069 write32be(Buf + 20, 0xe84c0008); // ld %r2,8(%r12) 1070 write32be(Buf + 24, 0xe96c0010); // ld %r11,16(%r12) 1071 write32be(Buf + 28, 0x4e800420); // bctr 1072 } 1073 1074 static std::pair<uint32_t, uint64_t> toAddr16Rel(uint32_t Type, uint64_t Val) { 1075 uint64_t V = Val - PPC64TocOffset; 1076 switch (Type) { 1077 case R_PPC64_TOC16: 1078 return {R_PPC64_ADDR16, V}; 1079 case R_PPC64_TOC16_DS: 1080 return {R_PPC64_ADDR16_DS, V}; 1081 case R_PPC64_TOC16_HA: 1082 return {R_PPC64_ADDR16_HA, V}; 1083 case R_PPC64_TOC16_HI: 1084 return {R_PPC64_ADDR16_HI, V}; 1085 case R_PPC64_TOC16_LO: 1086 return {R_PPC64_ADDR16_LO, V}; 1087 case R_PPC64_TOC16_LO_DS: 1088 return {R_PPC64_ADDR16_LO_DS, V}; 1089 default: 1090 return {Type, Val}; 1091 } 1092 } 1093 1094 void PPC64TargetInfo::relocateOne(uint8_t *Loc, uint32_t Type, 1095 uint64_t Val) const { 1096 // For a TOC-relative relocation, proceed in terms of the corresponding 1097 // ADDR16 relocation type. 1098 std::tie(Type, Val) = toAddr16Rel(Type, Val); 1099 1100 switch (Type) { 1101 case R_PPC64_ADDR14: { 1102 checkAlignment<4>(Val, Type); 1103 // Preserve the AA/LK bits in the branch instruction 1104 uint8_t AALK = Loc[3]; 1105 write16be(Loc + 2, (AALK & 3) | (Val & 0xfffc)); 1106 break; 1107 } 1108 case R_PPC64_ADDR16: 1109 checkInt<16>(Val, Type); 1110 write16be(Loc, Val); 1111 break; 1112 case R_PPC64_ADDR16_DS: 1113 checkInt<16>(Val, Type); 1114 write16be(Loc, (read16be(Loc) & 3) | (Val & ~3)); 1115 break; 1116 case R_PPC64_ADDR16_HA: 1117 case R_PPC64_REL16_HA: 1118 write16be(Loc, applyPPCHa(Val)); 1119 break; 1120 case R_PPC64_ADDR16_HI: 1121 case R_PPC64_REL16_HI: 1122 write16be(Loc, applyPPCHi(Val)); 1123 break; 1124 case R_PPC64_ADDR16_HIGHER: 1125 write16be(Loc, applyPPCHigher(Val)); 1126 break; 1127 case R_PPC64_ADDR16_HIGHERA: 1128 write16be(Loc, applyPPCHighera(Val)); 1129 break; 1130 case R_PPC64_ADDR16_HIGHEST: 1131 write16be(Loc, applyPPCHighest(Val)); 1132 break; 1133 case R_PPC64_ADDR16_HIGHESTA: 1134 write16be(Loc, applyPPCHighesta(Val)); 1135 break; 1136 case R_PPC64_ADDR16_LO: 1137 write16be(Loc, applyPPCLo(Val)); 1138 break; 1139 case R_PPC64_ADDR16_LO_DS: 1140 case R_PPC64_REL16_LO: 1141 write16be(Loc, (read16be(Loc) & 3) | (applyPPCLo(Val) & ~3)); 1142 break; 1143 case R_PPC64_ADDR32: 1144 case R_PPC64_REL32: 1145 checkInt<32>(Val, Type); 1146 write32be(Loc, Val); 1147 break; 1148 case R_PPC64_ADDR64: 1149 case R_PPC64_REL64: 1150 case R_PPC64_TOC: 1151 write64be(Loc, Val); 1152 break; 1153 case R_PPC64_REL24: { 1154 uint32_t Mask = 0x03FFFFFC; 1155 checkInt<24>(Val, Type); 1156 write32be(Loc, (read32be(Loc) & ~Mask) | (Val & Mask)); 1157 break; 1158 } 1159 default: 1160 fatal("unrecognized reloc " + Twine(Type)); 1161 } 1162 } 1163 1164 AArch64TargetInfo::AArch64TargetInfo() { 1165 CopyRel = R_AARCH64_COPY; 1166 RelativeRel = R_AARCH64_RELATIVE; 1167 IRelativeRel = R_AARCH64_IRELATIVE; 1168 GotRel = R_AARCH64_GLOB_DAT; 1169 PltRel = R_AARCH64_JUMP_SLOT; 1170 TlsDescRel = R_AARCH64_TLSDESC; 1171 TlsGotRel = R_AARCH64_TLS_TPREL64; 1172 GotEntrySize = 8; 1173 GotPltEntrySize = 8; 1174 PltEntrySize = 16; 1175 PltHeaderSize = 32; 1176 MaxPageSize = 65536; 1177 1178 // It doesn't seem to be documented anywhere, but tls on aarch64 uses variant 1179 // 1 of the tls structures and the tcb size is 16. 1180 TcbSize = 16; 1181 } 1182 1183 RelExpr AArch64TargetInfo::getRelExpr(uint32_t Type, 1184 const SymbolBody &S) const { 1185 switch (Type) { 1186 default: 1187 return R_ABS; 1188 case R_AARCH64_TLSDESC_ADR_PAGE21: 1189 return R_TLSDESC_PAGE; 1190 case R_AARCH64_TLSDESC_LD64_LO12_NC: 1191 case R_AARCH64_TLSDESC_ADD_LO12_NC: 1192 return R_TLSDESC; 1193 case R_AARCH64_TLSDESC_CALL: 1194 return R_TLSDESC_CALL; 1195 case R_AARCH64_TLSLE_ADD_TPREL_HI12: 1196 case R_AARCH64_TLSLE_ADD_TPREL_LO12_NC: 1197 return R_TLS; 1198 case R_AARCH64_CALL26: 1199 case R_AARCH64_CONDBR19: 1200 case R_AARCH64_JUMP26: 1201 case R_AARCH64_TSTBR14: 1202 return R_PLT_PC; 1203 case R_AARCH64_PREL16: 1204 case R_AARCH64_PREL32: 1205 case R_AARCH64_PREL64: 1206 case R_AARCH64_ADR_PREL_LO21: 1207 return R_PC; 1208 case R_AARCH64_ADR_PREL_PG_HI21: 1209 return R_PAGE_PC; 1210 case R_AARCH64_LD64_GOT_LO12_NC: 1211 case R_AARCH64_TLSIE_LD64_GOTTPREL_LO12_NC: 1212 return R_GOT; 1213 case R_AARCH64_ADR_GOT_PAGE: 1214 case R_AARCH64_TLSIE_ADR_GOTTPREL_PAGE21: 1215 return R_GOT_PAGE_PC; 1216 } 1217 } 1218 1219 RelExpr AArch64TargetInfo::adjustRelaxExpr(uint32_t Type, const uint8_t *Data, 1220 RelExpr Expr) const { 1221 if (Expr == R_RELAX_TLS_GD_TO_IE) { 1222 if (Type == R_AARCH64_TLSDESC_ADR_PAGE21) 1223 return R_RELAX_TLS_GD_TO_IE_PAGE_PC; 1224 return R_RELAX_TLS_GD_TO_IE_ABS; 1225 } 1226 return Expr; 1227 } 1228 1229 bool AArch64TargetInfo::usesOnlyLowPageBits(uint32_t Type) const { 1230 switch (Type) { 1231 default: 1232 return false; 1233 case R_AARCH64_ADD_ABS_LO12_NC: 1234 case R_AARCH64_LD64_GOT_LO12_NC: 1235 case R_AARCH64_LDST128_ABS_LO12_NC: 1236 case R_AARCH64_LDST16_ABS_LO12_NC: 1237 case R_AARCH64_LDST32_ABS_LO12_NC: 1238 case R_AARCH64_LDST64_ABS_LO12_NC: 1239 case R_AARCH64_LDST8_ABS_LO12_NC: 1240 case R_AARCH64_TLSDESC_ADD_LO12_NC: 1241 case R_AARCH64_TLSDESC_LD64_LO12_NC: 1242 case R_AARCH64_TLSIE_LD64_GOTTPREL_LO12_NC: 1243 return true; 1244 } 1245 } 1246 1247 bool AArch64TargetInfo::isTlsInitialExecRel(uint32_t Type) const { 1248 return Type == R_AARCH64_TLSIE_ADR_GOTTPREL_PAGE21 || 1249 Type == R_AARCH64_TLSIE_LD64_GOTTPREL_LO12_NC; 1250 } 1251 1252 uint32_t AArch64TargetInfo::getDynRel(uint32_t Type) const { 1253 if (Type == R_AARCH64_ABS32 || Type == R_AARCH64_ABS64) 1254 return Type; 1255 // Keep it going with a dummy value so that we can find more reloc errors. 1256 errorDynRel(Type); 1257 return R_AARCH64_ABS32; 1258 } 1259 1260 void AArch64TargetInfo::writeGotPlt(uint8_t *Buf, const SymbolBody &) const { 1261 write64le(Buf, In<ELF64LE>::Plt->getVA()); 1262 } 1263 1264 static uint64_t getAArch64Page(uint64_t Expr) { 1265 return Expr & (~static_cast<uint64_t>(0xFFF)); 1266 } 1267 1268 void AArch64TargetInfo::writePltHeader(uint8_t *Buf) const { 1269 const uint8_t PltData[] = { 1270 0xf0, 0x7b, 0xbf, 0xa9, // stp x16, x30, [sp,#-16]! 1271 0x10, 0x00, 0x00, 0x90, // adrp x16, Page(&(.plt.got[2])) 1272 0x11, 0x02, 0x40, 0xf9, // ldr x17, [x16, Offset(&(.plt.got[2]))] 1273 0x10, 0x02, 0x00, 0x91, // add x16, x16, Offset(&(.plt.got[2])) 1274 0x20, 0x02, 0x1f, 0xd6, // br x17 1275 0x1f, 0x20, 0x03, 0xd5, // nop 1276 0x1f, 0x20, 0x03, 0xd5, // nop 1277 0x1f, 0x20, 0x03, 0xd5 // nop 1278 }; 1279 memcpy(Buf, PltData, sizeof(PltData)); 1280 1281 uint64_t Got = In<ELF64LE>::GotPlt->getVA(); 1282 uint64_t Plt = In<ELF64LE>::Plt->getVA(); 1283 relocateOne(Buf + 4, R_AARCH64_ADR_PREL_PG_HI21, 1284 getAArch64Page(Got + 16) - getAArch64Page(Plt + 4)); 1285 relocateOne(Buf + 8, R_AARCH64_LDST64_ABS_LO12_NC, Got + 16); 1286 relocateOne(Buf + 12, R_AARCH64_ADD_ABS_LO12_NC, Got + 16); 1287 } 1288 1289 void AArch64TargetInfo::writePlt(uint8_t *Buf, uint64_t GotEntryAddr, 1290 uint64_t PltEntryAddr, int32_t Index, 1291 unsigned RelOff) const { 1292 const uint8_t Inst[] = { 1293 0x10, 0x00, 0x00, 0x90, // adrp x16, Page(&(.plt.got[n])) 1294 0x11, 0x02, 0x40, 0xf9, // ldr x17, [x16, Offset(&(.plt.got[n]))] 1295 0x10, 0x02, 0x00, 0x91, // add x16, x16, Offset(&(.plt.got[n])) 1296 0x20, 0x02, 0x1f, 0xd6 // br x17 1297 }; 1298 memcpy(Buf, Inst, sizeof(Inst)); 1299 1300 relocateOne(Buf, R_AARCH64_ADR_PREL_PG_HI21, 1301 getAArch64Page(GotEntryAddr) - getAArch64Page(PltEntryAddr)); 1302 relocateOne(Buf + 4, R_AARCH64_LDST64_ABS_LO12_NC, GotEntryAddr); 1303 relocateOne(Buf + 8, R_AARCH64_ADD_ABS_LO12_NC, GotEntryAddr); 1304 } 1305 1306 static void updateAArch64Addr(uint8_t *L, uint64_t Imm) { 1307 uint32_t ImmLo = (Imm & 0x3) << 29; 1308 uint32_t ImmHi = (Imm & 0x1FFFFC) << 3; 1309 uint64_t Mask = (0x3 << 29) | (0x1FFFFC << 3); 1310 write32le(L, (read32le(L) & ~Mask) | ImmLo | ImmHi); 1311 } 1312 1313 static inline void updateAArch64Add(uint8_t *L, uint64_t Imm) { 1314 or32le(L, (Imm & 0xFFF) << 10); 1315 } 1316 1317 void AArch64TargetInfo::relocateOne(uint8_t *Loc, uint32_t Type, 1318 uint64_t Val) const { 1319 switch (Type) { 1320 case R_AARCH64_ABS16: 1321 case R_AARCH64_PREL16: 1322 checkIntUInt<16>(Val, Type); 1323 write16le(Loc, Val); 1324 break; 1325 case R_AARCH64_ABS32: 1326 case R_AARCH64_PREL32: 1327 checkIntUInt<32>(Val, Type); 1328 write32le(Loc, Val); 1329 break; 1330 case R_AARCH64_ABS64: 1331 case R_AARCH64_PREL64: 1332 write64le(Loc, Val); 1333 break; 1334 case R_AARCH64_ADD_ABS_LO12_NC: 1335 // This relocation stores 12 bits and there's no instruction 1336 // to do it. Instead, we do a 32 bits store of the value 1337 // of r_addend bitwise-or'ed Loc. This assumes that the addend 1338 // bits in Loc are zero. 1339 or32le(Loc, (Val & 0xFFF) << 10); 1340 break; 1341 case R_AARCH64_ADR_GOT_PAGE: 1342 case R_AARCH64_ADR_PREL_PG_HI21: 1343 case R_AARCH64_TLSIE_ADR_GOTTPREL_PAGE21: 1344 case R_AARCH64_TLSDESC_ADR_PAGE21: 1345 checkInt<33>(Val, Type); 1346 updateAArch64Addr(Loc, Val >> 12); 1347 break; 1348 case R_AARCH64_ADR_PREL_LO21: 1349 checkInt<21>(Val, Type); 1350 updateAArch64Addr(Loc, Val); 1351 break; 1352 case R_AARCH64_CALL26: 1353 case R_AARCH64_JUMP26: 1354 checkInt<28>(Val, Type); 1355 or32le(Loc, (Val & 0x0FFFFFFC) >> 2); 1356 break; 1357 case R_AARCH64_CONDBR19: 1358 checkInt<21>(Val, Type); 1359 or32le(Loc, (Val & 0x1FFFFC) << 3); 1360 break; 1361 case R_AARCH64_LD64_GOT_LO12_NC: 1362 case R_AARCH64_TLSIE_LD64_GOTTPREL_LO12_NC: 1363 case R_AARCH64_TLSDESC_LD64_LO12_NC: 1364 checkAlignment<8>(Val, Type); 1365 or32le(Loc, (Val & 0xFF8) << 7); 1366 break; 1367 case R_AARCH64_LDST128_ABS_LO12_NC: 1368 or32le(Loc, (Val & 0x0FF8) << 6); 1369 break; 1370 case R_AARCH64_LDST16_ABS_LO12_NC: 1371 or32le(Loc, (Val & 0x0FFC) << 9); 1372 break; 1373 case R_AARCH64_LDST8_ABS_LO12_NC: 1374 or32le(Loc, (Val & 0xFFF) << 10); 1375 break; 1376 case R_AARCH64_LDST32_ABS_LO12_NC: 1377 or32le(Loc, (Val & 0xFFC) << 8); 1378 break; 1379 case R_AARCH64_LDST64_ABS_LO12_NC: 1380 or32le(Loc, (Val & 0xFF8) << 7); 1381 break; 1382 case R_AARCH64_MOVW_UABS_G0_NC: 1383 or32le(Loc, (Val & 0xFFFF) << 5); 1384 break; 1385 case R_AARCH64_MOVW_UABS_G1_NC: 1386 or32le(Loc, (Val & 0xFFFF0000) >> 11); 1387 break; 1388 case R_AARCH64_MOVW_UABS_G2_NC: 1389 or32le(Loc, (Val & 0xFFFF00000000) >> 27); 1390 break; 1391 case R_AARCH64_MOVW_UABS_G3: 1392 or32le(Loc, (Val & 0xFFFF000000000000) >> 43); 1393 break; 1394 case R_AARCH64_TSTBR14: 1395 checkInt<16>(Val, Type); 1396 or32le(Loc, (Val & 0xFFFC) << 3); 1397 break; 1398 case R_AARCH64_TLSLE_ADD_TPREL_HI12: 1399 checkInt<24>(Val, Type); 1400 updateAArch64Add(Loc, Val >> 12); 1401 break; 1402 case R_AARCH64_TLSLE_ADD_TPREL_LO12_NC: 1403 case R_AARCH64_TLSDESC_ADD_LO12_NC: 1404 updateAArch64Add(Loc, Val); 1405 break; 1406 default: 1407 fatal("unrecognized reloc " + Twine(Type)); 1408 } 1409 } 1410 1411 void AArch64TargetInfo::relaxTlsGdToLe(uint8_t *Loc, uint32_t Type, 1412 uint64_t Val) const { 1413 // TLSDESC Global-Dynamic relocation are in the form: 1414 // adrp x0, :tlsdesc:v [R_AARCH64_TLSDESC_ADR_PAGE21] 1415 // ldr x1, [x0, #:tlsdesc_lo12:v [R_AARCH64_TLSDESC_LD64_LO12_NC] 1416 // add x0, x0, :tlsdesc_los:v [_AARCH64_TLSDESC_ADD_LO12_NC] 1417 // .tlsdesccall [R_AARCH64_TLSDESC_CALL] 1418 // blr x1 1419 // And it can optimized to: 1420 // movz x0, #0x0, lsl #16 1421 // movk x0, #0x10 1422 // nop 1423 // nop 1424 checkUInt<32>(Val, Type); 1425 1426 switch (Type) { 1427 case R_AARCH64_TLSDESC_ADD_LO12_NC: 1428 case R_AARCH64_TLSDESC_CALL: 1429 write32le(Loc, 0xd503201f); // nop 1430 return; 1431 case R_AARCH64_TLSDESC_ADR_PAGE21: 1432 write32le(Loc, 0xd2a00000 | (((Val >> 16) & 0xffff) << 5)); // movz 1433 return; 1434 case R_AARCH64_TLSDESC_LD64_LO12_NC: 1435 write32le(Loc, 0xf2800000 | ((Val & 0xffff) << 5)); // movk 1436 return; 1437 default: 1438 llvm_unreachable("unsupported relocation for TLS GD to LE relaxation"); 1439 } 1440 } 1441 1442 void AArch64TargetInfo::relaxTlsGdToIe(uint8_t *Loc, uint32_t Type, 1443 uint64_t Val) const { 1444 // TLSDESC Global-Dynamic relocation are in the form: 1445 // adrp x0, :tlsdesc:v [R_AARCH64_TLSDESC_ADR_PAGE21] 1446 // ldr x1, [x0, #:tlsdesc_lo12:v [R_AARCH64_TLSDESC_LD64_LO12_NC] 1447 // add x0, x0, :tlsdesc_los:v [_AARCH64_TLSDESC_ADD_LO12_NC] 1448 // .tlsdesccall [R_AARCH64_TLSDESC_CALL] 1449 // blr x1 1450 // And it can optimized to: 1451 // adrp x0, :gottprel:v 1452 // ldr x0, [x0, :gottprel_lo12:v] 1453 // nop 1454 // nop 1455 1456 switch (Type) { 1457 case R_AARCH64_TLSDESC_ADD_LO12_NC: 1458 case R_AARCH64_TLSDESC_CALL: 1459 write32le(Loc, 0xd503201f); // nop 1460 break; 1461 case R_AARCH64_TLSDESC_ADR_PAGE21: 1462 write32le(Loc, 0x90000000); // adrp 1463 relocateOne(Loc, R_AARCH64_TLSIE_ADR_GOTTPREL_PAGE21, Val); 1464 break; 1465 case R_AARCH64_TLSDESC_LD64_LO12_NC: 1466 write32le(Loc, 0xf9400000); // ldr 1467 relocateOne(Loc, R_AARCH64_TLSIE_LD64_GOTTPREL_LO12_NC, Val); 1468 break; 1469 default: 1470 llvm_unreachable("unsupported relocation for TLS GD to LE relaxation"); 1471 } 1472 } 1473 1474 void AArch64TargetInfo::relaxTlsIeToLe(uint8_t *Loc, uint32_t Type, 1475 uint64_t Val) const { 1476 checkUInt<32>(Val, Type); 1477 1478 if (Type == R_AARCH64_TLSIE_ADR_GOTTPREL_PAGE21) { 1479 // Generate MOVZ. 1480 uint32_t RegNo = read32le(Loc) & 0x1f; 1481 write32le(Loc, (0xd2a00000 | RegNo) | (((Val >> 16) & 0xffff) << 5)); 1482 return; 1483 } 1484 if (Type == R_AARCH64_TLSIE_LD64_GOTTPREL_LO12_NC) { 1485 // Generate MOVK. 1486 uint32_t RegNo = read32le(Loc) & 0x1f; 1487 write32le(Loc, (0xf2800000 | RegNo) | ((Val & 0xffff) << 5)); 1488 return; 1489 } 1490 llvm_unreachable("invalid relocation for TLS IE to LE relaxation"); 1491 } 1492 1493 AMDGPUTargetInfo::AMDGPUTargetInfo() { 1494 RelativeRel = R_AMDGPU_REL64; 1495 GotRel = R_AMDGPU_ABS64; 1496 GotEntrySize = 8; 1497 } 1498 1499 void AMDGPUTargetInfo::relocateOne(uint8_t *Loc, uint32_t Type, 1500 uint64_t Val) const { 1501 switch (Type) { 1502 case R_AMDGPU_ABS32: 1503 case R_AMDGPU_GOTPCREL: 1504 case R_AMDGPU_GOTPCREL32_LO: 1505 case R_AMDGPU_REL32: 1506 case R_AMDGPU_REL32_LO: 1507 write32le(Loc, Val); 1508 break; 1509 case R_AMDGPU_ABS64: 1510 write64le(Loc, Val); 1511 break; 1512 case R_AMDGPU_GOTPCREL32_HI: 1513 case R_AMDGPU_REL32_HI: 1514 write32le(Loc, Val >> 32); 1515 break; 1516 default: 1517 fatal("unrecognized reloc " + Twine(Type)); 1518 } 1519 } 1520 1521 RelExpr AMDGPUTargetInfo::getRelExpr(uint32_t Type, const SymbolBody &S) const { 1522 switch (Type) { 1523 case R_AMDGPU_ABS32: 1524 case R_AMDGPU_ABS64: 1525 return R_ABS; 1526 case R_AMDGPU_REL32: 1527 case R_AMDGPU_REL32_LO: 1528 case R_AMDGPU_REL32_HI: 1529 return R_PC; 1530 case R_AMDGPU_GOTPCREL: 1531 case R_AMDGPU_GOTPCREL32_LO: 1532 case R_AMDGPU_GOTPCREL32_HI: 1533 return R_GOT_PC; 1534 default: 1535 fatal("do not know how to handle relocation " + Twine(Type)); 1536 } 1537 } 1538 1539 ARMTargetInfo::ARMTargetInfo() { 1540 CopyRel = R_ARM_COPY; 1541 RelativeRel = R_ARM_RELATIVE; 1542 IRelativeRel = R_ARM_IRELATIVE; 1543 GotRel = R_ARM_GLOB_DAT; 1544 PltRel = R_ARM_JUMP_SLOT; 1545 TlsGotRel = R_ARM_TLS_TPOFF32; 1546 TlsModuleIndexRel = R_ARM_TLS_DTPMOD32; 1547 TlsOffsetRel = R_ARM_TLS_DTPOFF32; 1548 GotEntrySize = 4; 1549 GotPltEntrySize = 4; 1550 PltEntrySize = 16; 1551 PltHeaderSize = 20; 1552 // ARM uses Variant 1 TLS 1553 TcbSize = 8; 1554 NeedsThunks = true; 1555 } 1556 1557 RelExpr ARMTargetInfo::getRelExpr(uint32_t Type, const SymbolBody &S) const { 1558 switch (Type) { 1559 default: 1560 return R_ABS; 1561 case R_ARM_THM_JUMP11: 1562 return R_PC; 1563 case R_ARM_CALL: 1564 case R_ARM_JUMP24: 1565 case R_ARM_PC24: 1566 case R_ARM_PLT32: 1567 case R_ARM_PREL31: 1568 case R_ARM_THM_JUMP19: 1569 case R_ARM_THM_JUMP24: 1570 case R_ARM_THM_CALL: 1571 return R_PLT_PC; 1572 case R_ARM_GOTOFF32: 1573 // (S + A) - GOT_ORG 1574 return R_GOTREL; 1575 case R_ARM_GOT_BREL: 1576 // GOT(S) + A - GOT_ORG 1577 return R_GOT_OFF; 1578 case R_ARM_GOT_PREL: 1579 case R_ARM_TLS_IE32: 1580 // GOT(S) + A - P 1581 return R_GOT_PC; 1582 case R_ARM_TARGET1: 1583 return Config->Target1Rel ? R_PC : R_ABS; 1584 case R_ARM_TARGET2: 1585 if (Config->Target2 == Target2Policy::Rel) 1586 return R_PC; 1587 if (Config->Target2 == Target2Policy::Abs) 1588 return R_ABS; 1589 return R_GOT_PC; 1590 case R_ARM_TLS_GD32: 1591 return R_TLSGD_PC; 1592 case R_ARM_TLS_LDM32: 1593 return R_TLSLD_PC; 1594 case R_ARM_BASE_PREL: 1595 // B(S) + A - P 1596 // FIXME: currently B(S) assumed to be .got, this may not hold for all 1597 // platforms. 1598 return R_GOTONLY_PC; 1599 case R_ARM_MOVW_PREL_NC: 1600 case R_ARM_MOVT_PREL: 1601 case R_ARM_REL32: 1602 case R_ARM_THM_MOVW_PREL_NC: 1603 case R_ARM_THM_MOVT_PREL: 1604 return R_PC; 1605 case R_ARM_NONE: 1606 return R_HINT; 1607 case R_ARM_TLS_LE32: 1608 return R_TLS; 1609 } 1610 } 1611 1612 uint32_t ARMTargetInfo::getDynRel(uint32_t Type) const { 1613 if (Type == R_ARM_TARGET1 && !Config->Target1Rel) 1614 return R_ARM_ABS32; 1615 if (Type == R_ARM_ABS32) 1616 return Type; 1617 // Keep it going with a dummy value so that we can find more reloc errors. 1618 errorDynRel(Type); 1619 return R_ARM_ABS32; 1620 } 1621 1622 void ARMTargetInfo::writeGotPlt(uint8_t *Buf, const SymbolBody &) const { 1623 write32le(Buf, In<ELF32LE>::Plt->getVA()); 1624 } 1625 1626 void ARMTargetInfo::writePltHeader(uint8_t *Buf) const { 1627 const uint8_t PltData[] = { 1628 0x04, 0xe0, 0x2d, 0xe5, // str lr, [sp,#-4]! 1629 0x04, 0xe0, 0x9f, 0xe5, // ldr lr, L2 1630 0x0e, 0xe0, 0x8f, 0xe0, // L1: add lr, pc, lr 1631 0x08, 0xf0, 0xbe, 0xe5, // ldr pc, [lr, #8] 1632 0x00, 0x00, 0x00, 0x00, // L2: .word &(.got.plt) - L1 - 8 1633 }; 1634 memcpy(Buf, PltData, sizeof(PltData)); 1635 uint64_t GotPlt = In<ELF32LE>::GotPlt->getVA(); 1636 uint64_t L1 = In<ELF32LE>::Plt->getVA() + 8; 1637 write32le(Buf + 16, GotPlt - L1 - 8); 1638 } 1639 1640 void ARMTargetInfo::writePlt(uint8_t *Buf, uint64_t GotEntryAddr, 1641 uint64_t PltEntryAddr, int32_t Index, 1642 unsigned RelOff) const { 1643 // FIXME: Using simple code sequence with simple relocations. 1644 // There is a more optimal sequence but it requires support for the group 1645 // relocations. See ELF for the ARM Architecture Appendix A.3 1646 const uint8_t PltData[] = { 1647 0x04, 0xc0, 0x9f, 0xe5, // ldr ip, L2 1648 0x0f, 0xc0, 0x8c, 0xe0, // L1: add ip, ip, pc 1649 0x00, 0xf0, 0x9c, 0xe5, // ldr pc, [ip] 1650 0x00, 0x00, 0x00, 0x00, // L2: .word Offset(&(.plt.got) - L1 - 8 1651 }; 1652 memcpy(Buf, PltData, sizeof(PltData)); 1653 uint64_t L1 = PltEntryAddr + 4; 1654 write32le(Buf + 12, GotEntryAddr - L1 - 8); 1655 } 1656 1657 RelExpr ARMTargetInfo::getThunkExpr(RelExpr Expr, uint32_t RelocType, 1658 const InputFile &File, 1659 const SymbolBody &S) const { 1660 // If S is an undefined weak symbol we don't need a Thunk 1661 if (S.isUndefined()) 1662 return Expr; 1663 // A state change from ARM to Thumb and vice versa must go through an 1664 // interworking thunk if the relocation type is not R_ARM_CALL or 1665 // R_ARM_THM_CALL. 1666 switch (RelocType) { 1667 case R_ARM_PC24: 1668 case R_ARM_PLT32: 1669 case R_ARM_JUMP24: 1670 // Source is ARM, all PLT entries are ARM so no interworking required. 1671 // Otherwise we need to interwork if Symbol has bit 0 set (Thumb). 1672 if (Expr == R_PC && ((S.getVA<ELF32LE>() & 1) == 1)) 1673 return R_THUNK_PC; 1674 break; 1675 case R_ARM_THM_JUMP19: 1676 case R_ARM_THM_JUMP24: 1677 // Source is Thumb, all PLT entries are ARM so interworking is required. 1678 // Otherwise we need to interwork if Symbol has bit 0 clear (ARM). 1679 if (Expr == R_PLT_PC) 1680 return R_THUNK_PLT_PC; 1681 if ((S.getVA<ELF32LE>() & 1) == 0) 1682 return R_THUNK_PC; 1683 break; 1684 } 1685 return Expr; 1686 } 1687 1688 void ARMTargetInfo::relocateOne(uint8_t *Loc, uint32_t Type, 1689 uint64_t Val) const { 1690 switch (Type) { 1691 case R_ARM_ABS32: 1692 case R_ARM_BASE_PREL: 1693 case R_ARM_GOTOFF32: 1694 case R_ARM_GOT_BREL: 1695 case R_ARM_GOT_PREL: 1696 case R_ARM_REL32: 1697 case R_ARM_TARGET1: 1698 case R_ARM_TARGET2: 1699 case R_ARM_TLS_GD32: 1700 case R_ARM_TLS_IE32: 1701 case R_ARM_TLS_LDM32: 1702 case R_ARM_TLS_LDO32: 1703 case R_ARM_TLS_LE32: 1704 write32le(Loc, Val); 1705 break; 1706 case R_ARM_PREL31: 1707 checkInt<31>(Val, Type); 1708 write32le(Loc, (read32le(Loc) & 0x80000000) | (Val & ~0x80000000)); 1709 break; 1710 case R_ARM_CALL: 1711 // R_ARM_CALL is used for BL and BLX instructions, depending on the 1712 // value of bit 0 of Val, we must select a BL or BLX instruction 1713 if (Val & 1) { 1714 // If bit 0 of Val is 1 the target is Thumb, we must select a BLX. 1715 // The BLX encoding is 0xfa:H:imm24 where Val = imm24:H:'1' 1716 checkInt<26>(Val, Type); 1717 write32le(Loc, 0xfa000000 | // opcode 1718 ((Val & 2) << 23) | // H 1719 ((Val >> 2) & 0x00ffffff)); // imm24 1720 break; 1721 } 1722 if ((read32le(Loc) & 0xfe000000) == 0xfa000000) 1723 // BLX (always unconditional) instruction to an ARM Target, select an 1724 // unconditional BL. 1725 write32le(Loc, 0xeb000000 | (read32le(Loc) & 0x00ffffff)); 1726 // fall through as BL encoding is shared with B 1727 case R_ARM_JUMP24: 1728 case R_ARM_PC24: 1729 case R_ARM_PLT32: 1730 checkInt<26>(Val, Type); 1731 write32le(Loc, (read32le(Loc) & ~0x00ffffff) | ((Val >> 2) & 0x00ffffff)); 1732 break; 1733 case R_ARM_THM_JUMP11: 1734 checkInt<12>(Val, Type); 1735 write16le(Loc, (read32le(Loc) & 0xf800) | ((Val >> 1) & 0x07ff)); 1736 break; 1737 case R_ARM_THM_JUMP19: 1738 // Encoding T3: Val = S:J2:J1:imm6:imm11:0 1739 checkInt<21>(Val, Type); 1740 write16le(Loc, 1741 (read16le(Loc) & 0xfbc0) | // opcode cond 1742 ((Val >> 10) & 0x0400) | // S 1743 ((Val >> 12) & 0x003f)); // imm6 1744 write16le(Loc + 2, 1745 0x8000 | // opcode 1746 ((Val >> 8) & 0x0800) | // J2 1747 ((Val >> 5) & 0x2000) | // J1 1748 ((Val >> 1) & 0x07ff)); // imm11 1749 break; 1750 case R_ARM_THM_CALL: 1751 // R_ARM_THM_CALL is used for BL and BLX instructions, depending on the 1752 // value of bit 0 of Val, we must select a BL or BLX instruction 1753 if ((Val & 1) == 0) { 1754 // Ensure BLX destination is 4-byte aligned. As BLX instruction may 1755 // only be two byte aligned. This must be done before overflow check 1756 Val = alignTo(Val, 4); 1757 } 1758 // Bit 12 is 0 for BLX, 1 for BL 1759 write16le(Loc + 2, (read16le(Loc + 2) & ~0x1000) | (Val & 1) << 12); 1760 // Fall through as rest of encoding is the same as B.W 1761 case R_ARM_THM_JUMP24: 1762 // Encoding B T4, BL T1, BLX T2: Val = S:I1:I2:imm10:imm11:0 1763 // FIXME: Use of I1 and I2 require v6T2ops 1764 checkInt<25>(Val, Type); 1765 write16le(Loc, 1766 0xf000 | // opcode 1767 ((Val >> 14) & 0x0400) | // S 1768 ((Val >> 12) & 0x03ff)); // imm10 1769 write16le(Loc + 2, 1770 (read16le(Loc + 2) & 0xd000) | // opcode 1771 (((~(Val >> 10)) ^ (Val >> 11)) & 0x2000) | // J1 1772 (((~(Val >> 11)) ^ (Val >> 13)) & 0x0800) | // J2 1773 ((Val >> 1) & 0x07ff)); // imm11 1774 break; 1775 case R_ARM_MOVW_ABS_NC: 1776 case R_ARM_MOVW_PREL_NC: 1777 write32le(Loc, (read32le(Loc) & ~0x000f0fff) | ((Val & 0xf000) << 4) | 1778 (Val & 0x0fff)); 1779 break; 1780 case R_ARM_MOVT_ABS: 1781 case R_ARM_MOVT_PREL: 1782 checkInt<32>(Val, Type); 1783 write32le(Loc, (read32le(Loc) & ~0x000f0fff) | 1784 (((Val >> 16) & 0xf000) << 4) | ((Val >> 16) & 0xfff)); 1785 break; 1786 case R_ARM_THM_MOVT_ABS: 1787 case R_ARM_THM_MOVT_PREL: 1788 // Encoding T1: A = imm4:i:imm3:imm8 1789 checkInt<32>(Val, Type); 1790 write16le(Loc, 1791 0xf2c0 | // opcode 1792 ((Val >> 17) & 0x0400) | // i 1793 ((Val >> 28) & 0x000f)); // imm4 1794 write16le(Loc + 2, 1795 (read16le(Loc + 2) & 0x8f00) | // opcode 1796 ((Val >> 12) & 0x7000) | // imm3 1797 ((Val >> 16) & 0x00ff)); // imm8 1798 break; 1799 case R_ARM_THM_MOVW_ABS_NC: 1800 case R_ARM_THM_MOVW_PREL_NC: 1801 // Encoding T3: A = imm4:i:imm3:imm8 1802 write16le(Loc, 1803 0xf240 | // opcode 1804 ((Val >> 1) & 0x0400) | // i 1805 ((Val >> 12) & 0x000f)); // imm4 1806 write16le(Loc + 2, 1807 (read16le(Loc + 2) & 0x8f00) | // opcode 1808 ((Val << 4) & 0x7000) | // imm3 1809 (Val & 0x00ff)); // imm8 1810 break; 1811 default: 1812 fatal("unrecognized reloc " + Twine(Type)); 1813 } 1814 } 1815 1816 uint64_t ARMTargetInfo::getImplicitAddend(const uint8_t *Buf, 1817 uint32_t Type) const { 1818 switch (Type) { 1819 default: 1820 return 0; 1821 case R_ARM_ABS32: 1822 case R_ARM_BASE_PREL: 1823 case R_ARM_GOTOFF32: 1824 case R_ARM_GOT_BREL: 1825 case R_ARM_GOT_PREL: 1826 case R_ARM_REL32: 1827 case R_ARM_TARGET1: 1828 case R_ARM_TARGET2: 1829 case R_ARM_TLS_GD32: 1830 case R_ARM_TLS_LDM32: 1831 case R_ARM_TLS_LDO32: 1832 case R_ARM_TLS_IE32: 1833 case R_ARM_TLS_LE32: 1834 return SignExtend64<32>(read32le(Buf)); 1835 case R_ARM_PREL31: 1836 return SignExtend64<31>(read32le(Buf)); 1837 case R_ARM_CALL: 1838 case R_ARM_JUMP24: 1839 case R_ARM_PC24: 1840 case R_ARM_PLT32: 1841 return SignExtend64<26>(read32le(Buf) << 2); 1842 case R_ARM_THM_JUMP11: 1843 return SignExtend64<12>(read16le(Buf) << 1); 1844 case R_ARM_THM_JUMP19: { 1845 // Encoding T3: A = S:J2:J1:imm10:imm6:0 1846 uint16_t Hi = read16le(Buf); 1847 uint16_t Lo = read16le(Buf + 2); 1848 return SignExtend64<20>(((Hi & 0x0400) << 10) | // S 1849 ((Lo & 0x0800) << 8) | // J2 1850 ((Lo & 0x2000) << 5) | // J1 1851 ((Hi & 0x003f) << 12) | // imm6 1852 ((Lo & 0x07ff) << 1)); // imm11:0 1853 } 1854 case R_ARM_THM_CALL: 1855 case R_ARM_THM_JUMP24: { 1856 // Encoding B T4, BL T1, BLX T2: A = S:I1:I2:imm10:imm11:0 1857 // I1 = NOT(J1 EOR S), I2 = NOT(J2 EOR S) 1858 // FIXME: I1 and I2 require v6T2ops 1859 uint16_t Hi = read16le(Buf); 1860 uint16_t Lo = read16le(Buf + 2); 1861 return SignExtend64<24>(((Hi & 0x0400) << 14) | // S 1862 (~((Lo ^ (Hi << 3)) << 10) & 0x00800000) | // I1 1863 (~((Lo ^ (Hi << 1)) << 11) & 0x00400000) | // I2 1864 ((Hi & 0x003ff) << 12) | // imm0 1865 ((Lo & 0x007ff) << 1)); // imm11:0 1866 } 1867 // ELF for the ARM Architecture 4.6.1.1 the implicit addend for MOVW and 1868 // MOVT is in the range -32768 <= A < 32768 1869 case R_ARM_MOVW_ABS_NC: 1870 case R_ARM_MOVT_ABS: 1871 case R_ARM_MOVW_PREL_NC: 1872 case R_ARM_MOVT_PREL: { 1873 uint64_t Val = read32le(Buf) & 0x000f0fff; 1874 return SignExtend64<16>(((Val & 0x000f0000) >> 4) | (Val & 0x00fff)); 1875 } 1876 case R_ARM_THM_MOVW_ABS_NC: 1877 case R_ARM_THM_MOVT_ABS: 1878 case R_ARM_THM_MOVW_PREL_NC: 1879 case R_ARM_THM_MOVT_PREL: { 1880 // Encoding T3: A = imm4:i:imm3:imm8 1881 uint16_t Hi = read16le(Buf); 1882 uint16_t Lo = read16le(Buf + 2); 1883 return SignExtend64<16>(((Hi & 0x000f) << 12) | // imm4 1884 ((Hi & 0x0400) << 1) | // i 1885 ((Lo & 0x7000) >> 4) | // imm3 1886 (Lo & 0x00ff)); // imm8 1887 } 1888 } 1889 } 1890 1891 bool ARMTargetInfo::isTlsLocalDynamicRel(uint32_t Type) const { 1892 return Type == R_ARM_TLS_LDO32 || Type == R_ARM_TLS_LDM32; 1893 } 1894 1895 bool ARMTargetInfo::isTlsGlobalDynamicRel(uint32_t Type) const { 1896 return Type == R_ARM_TLS_GD32; 1897 } 1898 1899 bool ARMTargetInfo::isTlsInitialExecRel(uint32_t Type) const { 1900 return Type == R_ARM_TLS_IE32; 1901 } 1902 1903 template <class ELFT> MipsTargetInfo<ELFT>::MipsTargetInfo() { 1904 GotPltHeaderEntriesNum = 2; 1905 MaxPageSize = 65536; 1906 GotEntrySize = sizeof(typename ELFT::uint); 1907 GotPltEntrySize = sizeof(typename ELFT::uint); 1908 PltEntrySize = 16; 1909 PltHeaderSize = 32; 1910 CopyRel = R_MIPS_COPY; 1911 PltRel = R_MIPS_JUMP_SLOT; 1912 NeedsThunks = true; 1913 if (ELFT::Is64Bits) { 1914 RelativeRel = (R_MIPS_64 << 8) | R_MIPS_REL32; 1915 TlsGotRel = R_MIPS_TLS_TPREL64; 1916 TlsModuleIndexRel = R_MIPS_TLS_DTPMOD64; 1917 TlsOffsetRel = R_MIPS_TLS_DTPREL64; 1918 } else { 1919 RelativeRel = R_MIPS_REL32; 1920 TlsGotRel = R_MIPS_TLS_TPREL32; 1921 TlsModuleIndexRel = R_MIPS_TLS_DTPMOD32; 1922 TlsOffsetRel = R_MIPS_TLS_DTPREL32; 1923 } 1924 } 1925 1926 template <class ELFT> 1927 RelExpr MipsTargetInfo<ELFT>::getRelExpr(uint32_t Type, 1928 const SymbolBody &S) const { 1929 // See comment in the calculateMipsRelChain. 1930 if (ELFT::Is64Bits || Config->MipsN32Abi) 1931 Type &= 0xff; 1932 switch (Type) { 1933 default: 1934 return R_ABS; 1935 case R_MIPS_JALR: 1936 return R_HINT; 1937 case R_MIPS_GPREL16: 1938 case R_MIPS_GPREL32: 1939 return R_MIPS_GOTREL; 1940 case R_MIPS_26: 1941 return R_PLT; 1942 case R_MIPS_HI16: 1943 case R_MIPS_LO16: 1944 case R_MIPS_GOT_OFST: 1945 // MIPS _gp_disp designates offset between start of function and 'gp' 1946 // pointer into GOT. __gnu_local_gp is equal to the current value of 1947 // the 'gp'. Therefore any relocations against them do not require 1948 // dynamic relocation. 1949 if (&S == ElfSym<ELFT>::MipsGpDisp) 1950 return R_PC; 1951 return R_ABS; 1952 case R_MIPS_PC32: 1953 case R_MIPS_PC16: 1954 case R_MIPS_PC19_S2: 1955 case R_MIPS_PC21_S2: 1956 case R_MIPS_PC26_S2: 1957 case R_MIPS_PCHI16: 1958 case R_MIPS_PCLO16: 1959 return R_PC; 1960 case R_MIPS_GOT16: 1961 if (S.isLocal()) 1962 return R_MIPS_GOT_LOCAL_PAGE; 1963 // fallthrough 1964 case R_MIPS_CALL16: 1965 case R_MIPS_GOT_DISP: 1966 case R_MIPS_TLS_GOTTPREL: 1967 return R_MIPS_GOT_OFF; 1968 case R_MIPS_CALL_HI16: 1969 case R_MIPS_CALL_LO16: 1970 case R_MIPS_GOT_HI16: 1971 case R_MIPS_GOT_LO16: 1972 return R_MIPS_GOT_OFF32; 1973 case R_MIPS_GOT_PAGE: 1974 return R_MIPS_GOT_LOCAL_PAGE; 1975 case R_MIPS_TLS_GD: 1976 return R_MIPS_TLSGD; 1977 case R_MIPS_TLS_LDM: 1978 return R_MIPS_TLSLD; 1979 } 1980 } 1981 1982 template <class ELFT> 1983 uint32_t MipsTargetInfo<ELFT>::getDynRel(uint32_t Type) const { 1984 if (Type == R_MIPS_32 || Type == R_MIPS_64) 1985 return RelativeRel; 1986 // Keep it going with a dummy value so that we can find more reloc errors. 1987 errorDynRel(Type); 1988 return R_MIPS_32; 1989 } 1990 1991 template <class ELFT> 1992 bool MipsTargetInfo<ELFT>::isTlsLocalDynamicRel(uint32_t Type) const { 1993 return Type == R_MIPS_TLS_LDM; 1994 } 1995 1996 template <class ELFT> 1997 bool MipsTargetInfo<ELFT>::isTlsGlobalDynamicRel(uint32_t Type) const { 1998 return Type == R_MIPS_TLS_GD; 1999 } 2000 2001 template <class ELFT> 2002 void MipsTargetInfo<ELFT>::writeGotPlt(uint8_t *Buf, const SymbolBody &) const { 2003 write32<ELFT::TargetEndianness>(Buf, In<ELFT>::Plt->getVA()); 2004 } 2005 2006 template <endianness E, uint8_t BSIZE, uint8_t SHIFT> 2007 static int64_t getPcRelocAddend(const uint8_t *Loc) { 2008 uint32_t Instr = read32<E>(Loc); 2009 uint32_t Mask = 0xffffffff >> (32 - BSIZE); 2010 return SignExtend64<BSIZE + SHIFT>((Instr & Mask) << SHIFT); 2011 } 2012 2013 template <endianness E, uint8_t BSIZE, uint8_t SHIFT> 2014 static void applyMipsPcReloc(uint8_t *Loc, uint32_t Type, uint64_t V) { 2015 uint32_t Mask = 0xffffffff >> (32 - BSIZE); 2016 uint32_t Instr = read32<E>(Loc); 2017 if (SHIFT > 0) 2018 checkAlignment<(1 << SHIFT)>(V, Type); 2019 checkInt<BSIZE + SHIFT>(V, Type); 2020 write32<E>(Loc, (Instr & ~Mask) | ((V >> SHIFT) & Mask)); 2021 } 2022 2023 template <endianness E> static void writeMipsHi16(uint8_t *Loc, uint64_t V) { 2024 uint32_t Instr = read32<E>(Loc); 2025 uint16_t Res = ((V + 0x8000) >> 16) & 0xffff; 2026 write32<E>(Loc, (Instr & 0xffff0000) | Res); 2027 } 2028 2029 template <endianness E> static void writeMipsHigher(uint8_t *Loc, uint64_t V) { 2030 uint32_t Instr = read32<E>(Loc); 2031 uint16_t Res = ((V + 0x80008000) >> 32) & 0xffff; 2032 write32<E>(Loc, (Instr & 0xffff0000) | Res); 2033 } 2034 2035 template <endianness E> static void writeMipsHighest(uint8_t *Loc, uint64_t V) { 2036 uint32_t Instr = read32<E>(Loc); 2037 uint16_t Res = ((V + 0x800080008000) >> 48) & 0xffff; 2038 write32<E>(Loc, (Instr & 0xffff0000) | Res); 2039 } 2040 2041 template <endianness E> static void writeMipsLo16(uint8_t *Loc, uint64_t V) { 2042 uint32_t Instr = read32<E>(Loc); 2043 write32<E>(Loc, (Instr & 0xffff0000) | (V & 0xffff)); 2044 } 2045 2046 template <class ELFT> static bool isMipsR6() { 2047 const auto &FirstObj = cast<ELFFileBase<ELFT>>(*Config->FirstElf); 2048 uint32_t Arch = FirstObj.getObj().getHeader()->e_flags & EF_MIPS_ARCH; 2049 return Arch == EF_MIPS_ARCH_32R6 || Arch == EF_MIPS_ARCH_64R6; 2050 } 2051 2052 template <class ELFT> 2053 void MipsTargetInfo<ELFT>::writePltHeader(uint8_t *Buf) const { 2054 const endianness E = ELFT::TargetEndianness; 2055 if (Config->MipsN32Abi) { 2056 write32<E>(Buf, 0x3c0e0000); // lui $14, %hi(&GOTPLT[0]) 2057 write32<E>(Buf + 4, 0x8dd90000); // lw $25, %lo(&GOTPLT[0])($14) 2058 write32<E>(Buf + 8, 0x25ce0000); // addiu $14, $14, %lo(&GOTPLT[0]) 2059 write32<E>(Buf + 12, 0x030ec023); // subu $24, $24, $14 2060 } else { 2061 write32<E>(Buf, 0x3c1c0000); // lui $28, %hi(&GOTPLT[0]) 2062 write32<E>(Buf + 4, 0x8f990000); // lw $25, %lo(&GOTPLT[0])($28) 2063 write32<E>(Buf + 8, 0x279c0000); // addiu $28, $28, %lo(&GOTPLT[0]) 2064 write32<E>(Buf + 12, 0x031cc023); // subu $24, $24, $28 2065 } 2066 write32<E>(Buf + 16, 0x03e07825); // move $15, $31 2067 write32<E>(Buf + 20, 0x0018c082); // srl $24, $24, 2 2068 write32<E>(Buf + 24, 0x0320f809); // jalr $25 2069 write32<E>(Buf + 28, 0x2718fffe); // subu $24, $24, 2 2070 uint64_t Got = In<ELFT>::GotPlt->getVA(); 2071 writeMipsHi16<E>(Buf, Got); 2072 writeMipsLo16<E>(Buf + 4, Got); 2073 writeMipsLo16<E>(Buf + 8, Got); 2074 } 2075 2076 template <class ELFT> 2077 void MipsTargetInfo<ELFT>::writePlt(uint8_t *Buf, uint64_t GotEntryAddr, 2078 uint64_t PltEntryAddr, int32_t Index, 2079 unsigned RelOff) const { 2080 const endianness E = ELFT::TargetEndianness; 2081 write32<E>(Buf, 0x3c0f0000); // lui $15, %hi(.got.plt entry) 2082 write32<E>(Buf + 4, 0x8df90000); // l[wd] $25, %lo(.got.plt entry)($15) 2083 // jr $25 2084 write32<E>(Buf + 8, isMipsR6<ELFT>() ? 0x03200009 : 0x03200008); 2085 write32<E>(Buf + 12, 0x25f80000); // addiu $24, $15, %lo(.got.plt entry) 2086 writeMipsHi16<E>(Buf, GotEntryAddr); 2087 writeMipsLo16<E>(Buf + 4, GotEntryAddr); 2088 writeMipsLo16<E>(Buf + 12, GotEntryAddr); 2089 } 2090 2091 template <class ELFT> 2092 RelExpr MipsTargetInfo<ELFT>::getThunkExpr(RelExpr Expr, uint32_t Type, 2093 const InputFile &File, 2094 const SymbolBody &S) const { 2095 // Any MIPS PIC code function is invoked with its address in register $t9. 2096 // So if we have a branch instruction from non-PIC code to the PIC one 2097 // we cannot make the jump directly and need to create a small stubs 2098 // to save the target function address. 2099 // See page 3-38 ftp://www.linux-mips.org/pub/linux/mips/doc/ABI/mipsabi.pdf 2100 if (Type != R_MIPS_26) 2101 return Expr; 2102 auto *F = dyn_cast<ELFFileBase<ELFT>>(&File); 2103 if (!F) 2104 return Expr; 2105 // If current file has PIC code, LA25 stub is not required. 2106 if (F->getObj().getHeader()->e_flags & EF_MIPS_PIC) 2107 return Expr; 2108 auto *D = dyn_cast<DefinedRegular<ELFT>>(&S); 2109 // LA25 is required if target file has PIC code 2110 // or target symbol is a PIC symbol. 2111 return D && D->isMipsPIC() ? R_THUNK_ABS : Expr; 2112 } 2113 2114 template <class ELFT> 2115 uint64_t MipsTargetInfo<ELFT>::getImplicitAddend(const uint8_t *Buf, 2116 uint32_t Type) const { 2117 const endianness E = ELFT::TargetEndianness; 2118 switch (Type) { 2119 default: 2120 return 0; 2121 case R_MIPS_32: 2122 case R_MIPS_GPREL32: 2123 case R_MIPS_TLS_DTPREL32: 2124 case R_MIPS_TLS_TPREL32: 2125 return read32<E>(Buf); 2126 case R_MIPS_26: 2127 // FIXME (simon): If the relocation target symbol is not a PLT entry 2128 // we should use another expression for calculation: 2129 // ((A << 2) | (P & 0xf0000000)) >> 2 2130 return SignExtend64<28>((read32<E>(Buf) & 0x3ffffff) << 2); 2131 case R_MIPS_GPREL16: 2132 case R_MIPS_LO16: 2133 case R_MIPS_PCLO16: 2134 case R_MIPS_TLS_DTPREL_HI16: 2135 case R_MIPS_TLS_DTPREL_LO16: 2136 case R_MIPS_TLS_TPREL_HI16: 2137 case R_MIPS_TLS_TPREL_LO16: 2138 return SignExtend64<16>(read32<E>(Buf)); 2139 case R_MIPS_PC16: 2140 return getPcRelocAddend<E, 16, 2>(Buf); 2141 case R_MIPS_PC19_S2: 2142 return getPcRelocAddend<E, 19, 2>(Buf); 2143 case R_MIPS_PC21_S2: 2144 return getPcRelocAddend<E, 21, 2>(Buf); 2145 case R_MIPS_PC26_S2: 2146 return getPcRelocAddend<E, 26, 2>(Buf); 2147 case R_MIPS_PC32: 2148 return getPcRelocAddend<E, 32, 0>(Buf); 2149 } 2150 } 2151 2152 static std::pair<uint32_t, uint64_t> calculateMipsRelChain(uint32_t Type, 2153 uint64_t Val) { 2154 // MIPS N64 ABI packs multiple relocations into the single relocation 2155 // record. In general, all up to three relocations can have arbitrary 2156 // types. In fact, Clang and GCC uses only a few combinations. For now, 2157 // we support two of them. That is allow to pass at least all LLVM 2158 // test suite cases. 2159 // <any relocation> / R_MIPS_SUB / R_MIPS_HI16 | R_MIPS_LO16 2160 // <any relocation> / R_MIPS_64 / R_MIPS_NONE 2161 // The first relocation is a 'real' relocation which is calculated 2162 // using the corresponding symbol's value. The second and the third 2163 // relocations used to modify result of the first one: extend it to 2164 // 64-bit, extract high or low part etc. For details, see part 2.9 Relocation 2165 // at the https://dmz-portal.mips.com/mw/images/8/82/007-4658-001.pdf 2166 uint32_t Type2 = (Type >> 8) & 0xff; 2167 uint32_t Type3 = (Type >> 16) & 0xff; 2168 if (Type2 == R_MIPS_NONE && Type3 == R_MIPS_NONE) 2169 return std::make_pair(Type, Val); 2170 if (Type2 == R_MIPS_64 && Type3 == R_MIPS_NONE) 2171 return std::make_pair(Type2, Val); 2172 if (Type2 == R_MIPS_SUB && (Type3 == R_MIPS_HI16 || Type3 == R_MIPS_LO16)) 2173 return std::make_pair(Type3, -Val); 2174 error("unsupported relocations combination " + Twine(Type)); 2175 return std::make_pair(Type & 0xff, Val); 2176 } 2177 2178 template <class ELFT> 2179 void MipsTargetInfo<ELFT>::relocateOne(uint8_t *Loc, uint32_t Type, 2180 uint64_t Val) const { 2181 const endianness E = ELFT::TargetEndianness; 2182 // Thread pointer and DRP offsets from the start of TLS data area. 2183 // https://www.linux-mips.org/wiki/NPTL 2184 if (Type == R_MIPS_TLS_DTPREL_HI16 || Type == R_MIPS_TLS_DTPREL_LO16 || 2185 Type == R_MIPS_TLS_DTPREL32 || Type == R_MIPS_TLS_DTPREL64) 2186 Val -= 0x8000; 2187 else if (Type == R_MIPS_TLS_TPREL_HI16 || Type == R_MIPS_TLS_TPREL_LO16 || 2188 Type == R_MIPS_TLS_TPREL32 || Type == R_MIPS_TLS_TPREL64) 2189 Val -= 0x7000; 2190 if (ELFT::Is64Bits || Config->MipsN32Abi) 2191 std::tie(Type, Val) = calculateMipsRelChain(Type, Val); 2192 switch (Type) { 2193 case R_MIPS_32: 2194 case R_MIPS_GPREL32: 2195 case R_MIPS_TLS_DTPREL32: 2196 case R_MIPS_TLS_TPREL32: 2197 write32<E>(Loc, Val); 2198 break; 2199 case R_MIPS_64: 2200 case R_MIPS_TLS_DTPREL64: 2201 case R_MIPS_TLS_TPREL64: 2202 write64<E>(Loc, Val); 2203 break; 2204 case R_MIPS_26: 2205 write32<E>(Loc, (read32<E>(Loc) & ~0x3ffffff) | ((Val >> 2) & 0x3ffffff)); 2206 break; 2207 case R_MIPS_GOT_DISP: 2208 case R_MIPS_GOT_PAGE: 2209 case R_MIPS_GOT16: 2210 case R_MIPS_GPREL16: 2211 case R_MIPS_TLS_GD: 2212 case R_MIPS_TLS_LDM: 2213 checkInt<16>(Val, Type); 2214 // fallthrough 2215 case R_MIPS_CALL16: 2216 case R_MIPS_CALL_LO16: 2217 case R_MIPS_GOT_LO16: 2218 case R_MIPS_GOT_OFST: 2219 case R_MIPS_LO16: 2220 case R_MIPS_PCLO16: 2221 case R_MIPS_TLS_DTPREL_LO16: 2222 case R_MIPS_TLS_GOTTPREL: 2223 case R_MIPS_TLS_TPREL_LO16: 2224 writeMipsLo16<E>(Loc, Val); 2225 break; 2226 case R_MIPS_CALL_HI16: 2227 case R_MIPS_GOT_HI16: 2228 case R_MIPS_HI16: 2229 case R_MIPS_PCHI16: 2230 case R_MIPS_TLS_DTPREL_HI16: 2231 case R_MIPS_TLS_TPREL_HI16: 2232 writeMipsHi16<E>(Loc, Val); 2233 break; 2234 case R_MIPS_HIGHER: 2235 writeMipsHigher<E>(Loc, Val); 2236 break; 2237 case R_MIPS_HIGHEST: 2238 writeMipsHighest<E>(Loc, Val); 2239 break; 2240 case R_MIPS_JALR: 2241 // Ignore this optimization relocation for now 2242 break; 2243 case R_MIPS_PC16: 2244 applyMipsPcReloc<E, 16, 2>(Loc, Type, Val); 2245 break; 2246 case R_MIPS_PC19_S2: 2247 applyMipsPcReloc<E, 19, 2>(Loc, Type, Val); 2248 break; 2249 case R_MIPS_PC21_S2: 2250 applyMipsPcReloc<E, 21, 2>(Loc, Type, Val); 2251 break; 2252 case R_MIPS_PC26_S2: 2253 applyMipsPcReloc<E, 26, 2>(Loc, Type, Val); 2254 break; 2255 case R_MIPS_PC32: 2256 applyMipsPcReloc<E, 32, 0>(Loc, Type, Val); 2257 break; 2258 default: 2259 fatal("unrecognized reloc " + Twine(Type)); 2260 } 2261 } 2262 2263 template <class ELFT> 2264 bool MipsTargetInfo<ELFT>::usesOnlyLowPageBits(uint32_t Type) const { 2265 return Type == R_MIPS_LO16 || Type == R_MIPS_GOT_OFST; 2266 } 2267 } 2268 } 2269