1 //===- MIPS.cpp -----------------------------------------------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #include "InputFiles.h" 10 #include "OutputSections.h" 11 #include "Symbols.h" 12 #include "SyntheticSections.h" 13 #include "Target.h" 14 #include "Thunks.h" 15 #include "lld/Common/ErrorHandler.h" 16 #include "llvm/Object/ELF.h" 17 18 using namespace llvm; 19 using namespace llvm::object; 20 using namespace llvm::ELF; 21 using namespace lld; 22 using namespace lld::elf; 23 24 namespace { 25 template <class ELFT> class MIPS final : public TargetInfo { 26 public: 27 MIPS(); 28 uint32_t calcEFlags() const override; 29 RelExpr getRelExpr(RelType type, const Symbol &s, 30 const uint8_t *loc) const override; 31 int64_t getImplicitAddend(const uint8_t *buf, RelType type) const override; 32 RelType getDynRel(RelType type) const override; 33 void writeGotPlt(uint8_t *buf, const Symbol &s) const override; 34 void writePltHeader(uint8_t *buf) const override; 35 void writePlt(uint8_t *buf, const Symbol &sym, 36 uint64_t pltEntryAddr) const override; 37 bool needsThunk(RelExpr expr, RelType type, const InputFile *file, 38 uint64_t branchAddr, const Symbol &s, 39 int64_t a) const override; 40 void relocate(uint8_t *loc, const Relocation &rel, 41 uint64_t val) const override; 42 bool usesOnlyLowPageBits(RelType type) const override; 43 }; 44 } // namespace 45 46 template <class ELFT> MIPS<ELFT>::MIPS() { 47 gotPltHeaderEntriesNum = 2; 48 defaultMaxPageSize = 65536; 49 gotBaseSymInGotPlt = false; 50 pltEntrySize = 16; 51 pltHeaderSize = 32; 52 copyRel = R_MIPS_COPY; 53 noneRel = R_MIPS_NONE; 54 pltRel = R_MIPS_JUMP_SLOT; 55 needsThunks = true; 56 57 // Set `sigrie 1` as a trap instruction. 58 write32(trapInstr.data(), 0x04170001); 59 60 if (ELFT::Is64Bits) { 61 relativeRel = (R_MIPS_64 << 8) | R_MIPS_REL32; 62 symbolicRel = R_MIPS_64; 63 tlsGotRel = R_MIPS_TLS_TPREL64; 64 tlsModuleIndexRel = R_MIPS_TLS_DTPMOD64; 65 tlsOffsetRel = R_MIPS_TLS_DTPREL64; 66 } else { 67 relativeRel = R_MIPS_REL32; 68 symbolicRel = R_MIPS_32; 69 tlsGotRel = R_MIPS_TLS_TPREL32; 70 tlsModuleIndexRel = R_MIPS_TLS_DTPMOD32; 71 tlsOffsetRel = R_MIPS_TLS_DTPREL32; 72 } 73 } 74 75 template <class ELFT> uint32_t MIPS<ELFT>::calcEFlags() const { 76 return calcMipsEFlags<ELFT>(); 77 } 78 79 template <class ELFT> 80 RelExpr MIPS<ELFT>::getRelExpr(RelType type, const Symbol &s, 81 const uint8_t *loc) const { 82 // See comment in the calculateMipsRelChain. 83 if (ELFT::Is64Bits || config->mipsN32Abi) 84 type &= 0xff; 85 86 switch (type) { 87 case R_MIPS_JALR: 88 // Older versions of clang would erroneously emit this relocation not only 89 // against functions (loaded from the GOT) but also against data symbols 90 // (e.g. a table of function pointers). When we encounter this, ignore the 91 // relocation and emit a warning instead. 92 if (!s.isFunc() && s.type != STT_NOTYPE) { 93 warn(getErrorLocation(loc) + 94 "found R_MIPS_JALR relocation against non-function symbol " + 95 toString(s) + ". This is invalid and most likely a compiler bug."); 96 return R_NONE; 97 } 98 99 // If the target symbol is not preemptible and is not microMIPS, 100 // it might be possible to replace jalr/jr instruction by bal/b. 101 // It depends on the target symbol's offset. 102 if (!s.isPreemptible && !(s.getVA() & 0x1)) 103 return R_PC; 104 return R_NONE; 105 case R_MICROMIPS_JALR: 106 return R_NONE; 107 case R_MIPS_GPREL16: 108 case R_MIPS_GPREL32: 109 case R_MICROMIPS_GPREL16: 110 case R_MICROMIPS_GPREL7_S2: 111 return R_MIPS_GOTREL; 112 case R_MIPS_26: 113 case R_MICROMIPS_26_S1: 114 return R_PLT; 115 case R_MICROMIPS_PC26_S1: 116 return R_PLT_PC; 117 case R_MIPS_HI16: 118 case R_MIPS_LO16: 119 case R_MIPS_HIGHER: 120 case R_MIPS_HIGHEST: 121 case R_MICROMIPS_HI16: 122 case R_MICROMIPS_LO16: 123 // R_MIPS_HI16/R_MIPS_LO16 relocations against _gp_disp calculate 124 // offset between start of function and 'gp' value which by default 125 // equal to the start of .got section. In that case we consider these 126 // relocations as relative. 127 if (&s == ElfSym::mipsGpDisp) 128 return R_MIPS_GOT_GP_PC; 129 if (&s == ElfSym::mipsLocalGp) 130 return R_MIPS_GOT_GP; 131 LLVM_FALLTHROUGH; 132 case R_MIPS_32: 133 case R_MIPS_64: 134 case R_MIPS_GOT_OFST: 135 case R_MIPS_SUB: 136 case R_MIPS_TLS_DTPREL_HI16: 137 case R_MIPS_TLS_DTPREL_LO16: 138 case R_MIPS_TLS_DTPREL32: 139 case R_MIPS_TLS_DTPREL64: 140 case R_MICROMIPS_TLS_DTPREL_HI16: 141 case R_MICROMIPS_TLS_DTPREL_LO16: 142 return R_ABS; 143 case R_MIPS_TLS_TPREL_HI16: 144 case R_MIPS_TLS_TPREL_LO16: 145 case R_MIPS_TLS_TPREL32: 146 case R_MIPS_TLS_TPREL64: 147 case R_MICROMIPS_TLS_TPREL_HI16: 148 case R_MICROMIPS_TLS_TPREL_LO16: 149 return R_TPREL; 150 case R_MIPS_PC32: 151 case R_MIPS_PC16: 152 case R_MIPS_PC19_S2: 153 case R_MIPS_PC21_S2: 154 case R_MIPS_PC26_S2: 155 case R_MIPS_PCHI16: 156 case R_MIPS_PCLO16: 157 case R_MICROMIPS_PC7_S1: 158 case R_MICROMIPS_PC10_S1: 159 case R_MICROMIPS_PC16_S1: 160 case R_MICROMIPS_PC18_S3: 161 case R_MICROMIPS_PC19_S2: 162 case R_MICROMIPS_PC23_S2: 163 case R_MICROMIPS_PC21_S1: 164 return R_PC; 165 case R_MIPS_GOT16: 166 case R_MICROMIPS_GOT16: 167 if (s.isLocal()) 168 return R_MIPS_GOT_LOCAL_PAGE; 169 LLVM_FALLTHROUGH; 170 case R_MIPS_CALL16: 171 case R_MIPS_GOT_DISP: 172 case R_MIPS_TLS_GOTTPREL: 173 case R_MICROMIPS_CALL16: 174 case R_MICROMIPS_TLS_GOTTPREL: 175 return R_MIPS_GOT_OFF; 176 case R_MIPS_CALL_HI16: 177 case R_MIPS_CALL_LO16: 178 case R_MIPS_GOT_HI16: 179 case R_MIPS_GOT_LO16: 180 case R_MICROMIPS_CALL_HI16: 181 case R_MICROMIPS_CALL_LO16: 182 case R_MICROMIPS_GOT_HI16: 183 case R_MICROMIPS_GOT_LO16: 184 return R_MIPS_GOT_OFF32; 185 case R_MIPS_GOT_PAGE: 186 return R_MIPS_GOT_LOCAL_PAGE; 187 case R_MIPS_TLS_GD: 188 case R_MICROMIPS_TLS_GD: 189 return R_MIPS_TLSGD; 190 case R_MIPS_TLS_LDM: 191 case R_MICROMIPS_TLS_LDM: 192 return R_MIPS_TLSLD; 193 case R_MIPS_NONE: 194 return R_NONE; 195 default: 196 error(getErrorLocation(loc) + "unknown relocation (" + Twine(type) + 197 ") against symbol " + toString(s)); 198 return R_NONE; 199 } 200 } 201 202 template <class ELFT> RelType MIPS<ELFT>::getDynRel(RelType type) const { 203 if (type == symbolicRel) 204 return type; 205 return R_MIPS_NONE; 206 } 207 208 template <class ELFT> 209 void MIPS<ELFT>::writeGotPlt(uint8_t *buf, const Symbol &) const { 210 uint64_t va = in.plt->getVA(); 211 if (isMicroMips()) 212 va |= 1; 213 write32(buf, va); 214 } 215 216 template <endianness E> static uint32_t readShuffle(const uint8_t *loc) { 217 // The major opcode of a microMIPS instruction needs to appear 218 // in the first 16-bit word (lowest address) for efficient hardware 219 // decode so that it knows if the instruction is 16-bit or 32-bit 220 // as early as possible. To do so, little-endian binaries keep 16-bit 221 // words in a big-endian order. That is why we have to swap these 222 // words to get a correct value. 223 uint32_t v = read32(loc); 224 if (E == support::little) 225 return (v << 16) | (v >> 16); 226 return v; 227 } 228 229 static void writeValue(uint8_t *loc, uint64_t v, uint8_t bitsSize, 230 uint8_t shift) { 231 uint32_t instr = read32(loc); 232 uint32_t mask = 0xffffffff >> (32 - bitsSize); 233 uint32_t data = (instr & ~mask) | ((v >> shift) & mask); 234 write32(loc, data); 235 } 236 237 template <endianness E> 238 static void writeShuffleValue(uint8_t *loc, uint64_t v, uint8_t bitsSize, 239 uint8_t shift) { 240 // See comments in readShuffle for purpose of this code. 241 uint16_t *words = (uint16_t *)loc; 242 if (E == support::little) 243 std::swap(words[0], words[1]); 244 245 writeValue(loc, v, bitsSize, shift); 246 247 if (E == support::little) 248 std::swap(words[0], words[1]); 249 } 250 251 template <endianness E> 252 static void writeMicroRelocation16(uint8_t *loc, uint64_t v, uint8_t bitsSize, 253 uint8_t shift) { 254 uint16_t instr = read16(loc); 255 uint16_t mask = 0xffff >> (16 - bitsSize); 256 uint16_t data = (instr & ~mask) | ((v >> shift) & mask); 257 write16(loc, data); 258 } 259 260 template <class ELFT> void MIPS<ELFT>::writePltHeader(uint8_t *buf) const { 261 if (isMicroMips()) { 262 uint64_t gotPlt = in.gotPlt->getVA(); 263 uint64_t plt = in.plt->getVA(); 264 // Overwrite trap instructions written by Writer::writeTrapInstr. 265 memset(buf, 0, pltHeaderSize); 266 267 write16(buf, isMipsR6() ? 0x7860 : 0x7980); // addiupc v1, (GOTPLT) - . 268 write16(buf + 4, 0xff23); // lw $25, 0($3) 269 write16(buf + 8, 0x0535); // subu16 $2, $2, $3 270 write16(buf + 10, 0x2525); // srl16 $2, $2, 2 271 write16(buf + 12, 0x3302); // addiu $24, $2, -2 272 write16(buf + 14, 0xfffe); 273 write16(buf + 16, 0x0dff); // move $15, $31 274 if (isMipsR6()) { 275 write16(buf + 18, 0x0f83); // move $28, $3 276 write16(buf + 20, 0x472b); // jalrc $25 277 write16(buf + 22, 0x0c00); // nop 278 relocateNoSym(buf, R_MICROMIPS_PC19_S2, gotPlt - plt); 279 } else { 280 write16(buf + 18, 0x45f9); // jalrc $25 281 write16(buf + 20, 0x0f83); // move $28, $3 282 write16(buf + 22, 0x0c00); // nop 283 relocateNoSym(buf, R_MICROMIPS_PC23_S2, gotPlt - plt); 284 } 285 return; 286 } 287 288 if (config->mipsN32Abi) { 289 write32(buf, 0x3c0e0000); // lui $14, %hi(&GOTPLT[0]) 290 write32(buf + 4, 0x8dd90000); // lw $25, %lo(&GOTPLT[0])($14) 291 write32(buf + 8, 0x25ce0000); // addiu $14, $14, %lo(&GOTPLT[0]) 292 write32(buf + 12, 0x030ec023); // subu $24, $24, $14 293 write32(buf + 16, 0x03e07825); // move $15, $31 294 write32(buf + 20, 0x0018c082); // srl $24, $24, 2 295 } else if (ELFT::Is64Bits) { 296 write32(buf, 0x3c0e0000); // lui $14, %hi(&GOTPLT[0]) 297 write32(buf + 4, 0xddd90000); // ld $25, %lo(&GOTPLT[0])($14) 298 write32(buf + 8, 0x25ce0000); // addiu $14, $14, %lo(&GOTPLT[0]) 299 write32(buf + 12, 0x030ec023); // subu $24, $24, $14 300 write32(buf + 16, 0x03e07825); // move $15, $31 301 write32(buf + 20, 0x0018c0c2); // srl $24, $24, 3 302 } else { 303 write32(buf, 0x3c1c0000); // lui $28, %hi(&GOTPLT[0]) 304 write32(buf + 4, 0x8f990000); // lw $25, %lo(&GOTPLT[0])($28) 305 write32(buf + 8, 0x279c0000); // addiu $28, $28, %lo(&GOTPLT[0]) 306 write32(buf + 12, 0x031cc023); // subu $24, $24, $28 307 write32(buf + 16, 0x03e07825); // move $15, $31 308 write32(buf + 20, 0x0018c082); // srl $24, $24, 2 309 } 310 311 uint32_t jalrInst = config->zHazardplt ? 0x0320fc09 : 0x0320f809; 312 write32(buf + 24, jalrInst); // jalr.hb $25 or jalr $25 313 write32(buf + 28, 0x2718fffe); // subu $24, $24, 2 314 315 uint64_t gotPlt = in.gotPlt->getVA(); 316 writeValue(buf, gotPlt + 0x8000, 16, 16); 317 writeValue(buf + 4, gotPlt, 16, 0); 318 writeValue(buf + 8, gotPlt, 16, 0); 319 } 320 321 template <class ELFT> 322 void MIPS<ELFT>::writePlt(uint8_t *buf, const Symbol &sym, 323 uint64_t pltEntryAddr) const { 324 uint64_t gotPltEntryAddr = sym.getGotPltVA(); 325 if (isMicroMips()) { 326 // Overwrite trap instructions written by Writer::writeTrapInstr. 327 memset(buf, 0, pltEntrySize); 328 329 if (isMipsR6()) { 330 write16(buf, 0x7840); // addiupc $2, (GOTPLT) - . 331 write16(buf + 4, 0xff22); // lw $25, 0($2) 332 write16(buf + 8, 0x0f02); // move $24, $2 333 write16(buf + 10, 0x4723); // jrc $25 / jr16 $25 334 relocateNoSym(buf, R_MICROMIPS_PC19_S2, gotPltEntryAddr - pltEntryAddr); 335 } else { 336 write16(buf, 0x7900); // addiupc $2, (GOTPLT) - . 337 write16(buf + 4, 0xff22); // lw $25, 0($2) 338 write16(buf + 8, 0x4599); // jrc $25 / jr16 $25 339 write16(buf + 10, 0x0f02); // move $24, $2 340 relocateNoSym(buf, R_MICROMIPS_PC23_S2, gotPltEntryAddr - pltEntryAddr); 341 } 342 return; 343 } 344 345 uint32_t loadInst = ELFT::Is64Bits ? 0xddf90000 : 0x8df90000; 346 uint32_t jrInst = isMipsR6() ? (config->zHazardplt ? 0x03200409 : 0x03200009) 347 : (config->zHazardplt ? 0x03200408 : 0x03200008); 348 uint32_t addInst = ELFT::Is64Bits ? 0x65f80000 : 0x25f80000; 349 350 write32(buf, 0x3c0f0000); // lui $15, %hi(.got.plt entry) 351 write32(buf + 4, loadInst); // l[wd] $25, %lo(.got.plt entry)($15) 352 write32(buf + 8, jrInst); // jr $25 / jr.hb $25 353 write32(buf + 12, addInst); // [d]addiu $24, $15, %lo(.got.plt entry) 354 writeValue(buf, gotPltEntryAddr + 0x8000, 16, 16); 355 writeValue(buf + 4, gotPltEntryAddr, 16, 0); 356 writeValue(buf + 12, gotPltEntryAddr, 16, 0); 357 } 358 359 template <class ELFT> 360 bool MIPS<ELFT>::needsThunk(RelExpr expr, RelType type, const InputFile *file, 361 uint64_t branchAddr, const Symbol &s, 362 int64_t /*a*/) const { 363 // Any MIPS PIC code function is invoked with its address in register $t9. 364 // So if we have a branch instruction from non-PIC code to the PIC one 365 // we cannot make the jump directly and need to create a small stubs 366 // to save the target function address. 367 // See page 3-38 ftp://www.linux-mips.org/pub/linux/mips/doc/ABI/mipsabi.pdf 368 if (type != R_MIPS_26 && type != R_MIPS_PC26_S2 && 369 type != R_MICROMIPS_26_S1 && type != R_MICROMIPS_PC26_S1) 370 return false; 371 auto *f = dyn_cast_or_null<ObjFile<ELFT>>(file); 372 if (!f) 373 return false; 374 // If current file has PIC code, LA25 stub is not required. 375 if (f->getObj().getHeader().e_flags & EF_MIPS_PIC) 376 return false; 377 auto *d = dyn_cast<Defined>(&s); 378 // LA25 is required if target file has PIC code 379 // or target symbol is a PIC symbol. 380 return d && isMipsPIC<ELFT>(d); 381 } 382 383 template <class ELFT> 384 int64_t MIPS<ELFT>::getImplicitAddend(const uint8_t *buf, RelType type) const { 385 const endianness e = ELFT::TargetEndianness; 386 switch (type) { 387 case R_MIPS_32: 388 case R_MIPS_REL32: 389 case R_MIPS_GPREL32: 390 case R_MIPS_TLS_DTPREL32: 391 case R_MIPS_TLS_DTPMOD32: 392 case R_MIPS_TLS_TPREL32: 393 return SignExtend64<32>(read32(buf)); 394 case R_MIPS_26: 395 // FIXME (simon): If the relocation target symbol is not a PLT entry 396 // we should use another expression for calculation: 397 // ((A << 2) | (P & 0xf0000000)) >> 2 398 return SignExtend64<28>(read32(buf) << 2); 399 case R_MIPS_CALL_HI16: 400 case R_MIPS_GOT16: 401 case R_MIPS_GOT_HI16: 402 case R_MIPS_HI16: 403 case R_MIPS_PCHI16: 404 return SignExtend64<16>(read32(buf)) << 16; 405 case R_MIPS_CALL16: 406 case R_MIPS_CALL_LO16: 407 case R_MIPS_GOT_LO16: 408 case R_MIPS_GPREL16: 409 case R_MIPS_LO16: 410 case R_MIPS_PCLO16: 411 case R_MIPS_TLS_DTPREL_HI16: 412 case R_MIPS_TLS_DTPREL_LO16: 413 case R_MIPS_TLS_GD: 414 case R_MIPS_TLS_GOTTPREL: 415 case R_MIPS_TLS_LDM: 416 case R_MIPS_TLS_TPREL_HI16: 417 case R_MIPS_TLS_TPREL_LO16: 418 return SignExtend64<16>(read32(buf)); 419 case R_MICROMIPS_GOT16: 420 case R_MICROMIPS_HI16: 421 return SignExtend64<16>(readShuffle<e>(buf)) << 16; 422 case R_MICROMIPS_CALL16: 423 case R_MICROMIPS_GPREL16: 424 case R_MICROMIPS_LO16: 425 case R_MICROMIPS_TLS_DTPREL_HI16: 426 case R_MICROMIPS_TLS_DTPREL_LO16: 427 case R_MICROMIPS_TLS_GD: 428 case R_MICROMIPS_TLS_GOTTPREL: 429 case R_MICROMIPS_TLS_LDM: 430 case R_MICROMIPS_TLS_TPREL_HI16: 431 case R_MICROMIPS_TLS_TPREL_LO16: 432 return SignExtend64<16>(readShuffle<e>(buf)); 433 case R_MICROMIPS_GPREL7_S2: 434 return SignExtend64<9>(readShuffle<e>(buf) << 2); 435 case R_MIPS_PC16: 436 return SignExtend64<18>(read32(buf) << 2); 437 case R_MIPS_PC19_S2: 438 return SignExtend64<21>(read32(buf) << 2); 439 case R_MIPS_PC21_S2: 440 return SignExtend64<23>(read32(buf) << 2); 441 case R_MIPS_PC26_S2: 442 return SignExtend64<28>(read32(buf) << 2); 443 case R_MIPS_PC32: 444 return SignExtend64<32>(read32(buf)); 445 case R_MICROMIPS_26_S1: 446 return SignExtend64<27>(readShuffle<e>(buf) << 1); 447 case R_MICROMIPS_PC7_S1: 448 return SignExtend64<8>(read16(buf) << 1); 449 case R_MICROMIPS_PC10_S1: 450 return SignExtend64<11>(read16(buf) << 1); 451 case R_MICROMIPS_PC16_S1: 452 return SignExtend64<17>(readShuffle<e>(buf) << 1); 453 case R_MICROMIPS_PC18_S3: 454 return SignExtend64<21>(readShuffle<e>(buf) << 3); 455 case R_MICROMIPS_PC19_S2: 456 return SignExtend64<21>(readShuffle<e>(buf) << 2); 457 case R_MICROMIPS_PC21_S1: 458 return SignExtend64<22>(readShuffle<e>(buf) << 1); 459 case R_MICROMIPS_PC23_S2: 460 return SignExtend64<25>(readShuffle<e>(buf) << 2); 461 case R_MICROMIPS_PC26_S1: 462 return SignExtend64<27>(readShuffle<e>(buf) << 1); 463 case R_MIPS_64: 464 case R_MIPS_TLS_DTPMOD64: 465 case R_MIPS_TLS_DTPREL64: 466 case R_MIPS_TLS_TPREL64: 467 case (R_MIPS_64 << 8) | R_MIPS_REL32: 468 return read64(buf); 469 case R_MIPS_COPY: 470 return config->is64 ? read64(buf) : read32(buf); 471 case R_MIPS_NONE: 472 case R_MIPS_JUMP_SLOT: 473 case R_MIPS_JALR: 474 // These relocations are defined as not having an implicit addend. 475 return 0; 476 default: 477 internalLinkerError(getErrorLocation(buf), 478 "cannot read addend for relocation " + toString(type)); 479 return 0; 480 } 481 } 482 483 static std::pair<uint32_t, uint64_t> 484 calculateMipsRelChain(uint8_t *loc, RelType type, uint64_t val) { 485 // MIPS N64 ABI packs multiple relocations into the single relocation 486 // record. In general, all up to three relocations can have arbitrary 487 // types. In fact, Clang and GCC uses only a few combinations. For now, 488 // we support two of them. That is allow to pass at least all LLVM 489 // test suite cases. 490 // <any relocation> / R_MIPS_SUB / R_MIPS_HI16 | R_MIPS_LO16 491 // <any relocation> / R_MIPS_64 / R_MIPS_NONE 492 // The first relocation is a 'real' relocation which is calculated 493 // using the corresponding symbol's value. The second and the third 494 // relocations used to modify result of the first one: extend it to 495 // 64-bit, extract high or low part etc. For details, see part 2.9 Relocation 496 // at the https://dmz-portal.mips.com/mw/images/8/82/007-4658-001.pdf 497 RelType type2 = (type >> 8) & 0xff; 498 RelType type3 = (type >> 16) & 0xff; 499 if (type2 == R_MIPS_NONE && type3 == R_MIPS_NONE) 500 return std::make_pair(type, val); 501 if (type2 == R_MIPS_64 && type3 == R_MIPS_NONE) 502 return std::make_pair(type2, val); 503 if (type2 == R_MIPS_SUB && (type3 == R_MIPS_HI16 || type3 == R_MIPS_LO16)) 504 return std::make_pair(type3, -val); 505 error(getErrorLocation(loc) + "unsupported relocations combination " + 506 Twine(type)); 507 return std::make_pair(type & 0xff, val); 508 } 509 510 static bool isBranchReloc(RelType type) { 511 return type == R_MIPS_26 || type == R_MIPS_PC26_S2 || 512 type == R_MIPS_PC21_S2 || type == R_MIPS_PC16; 513 } 514 515 static bool isMicroBranchReloc(RelType type) { 516 return type == R_MICROMIPS_26_S1 || type == R_MICROMIPS_PC16_S1 || 517 type == R_MICROMIPS_PC10_S1 || type == R_MICROMIPS_PC7_S1; 518 } 519 520 template <class ELFT> 521 static uint64_t fixupCrossModeJump(uint8_t *loc, RelType type, uint64_t val) { 522 // Here we need to detect jump/branch from regular MIPS code 523 // to a microMIPS target and vice versa. In that cases jump 524 // instructions need to be replaced by their "cross-mode" 525 // equivalents. 526 const endianness e = ELFT::TargetEndianness; 527 bool isMicroTgt = val & 0x1; 528 bool isCrossJump = (isMicroTgt && isBranchReloc(type)) || 529 (!isMicroTgt && isMicroBranchReloc(type)); 530 if (!isCrossJump) 531 return val; 532 533 switch (type) { 534 case R_MIPS_26: { 535 uint32_t inst = read32(loc) >> 26; 536 if (inst == 0x3 || inst == 0x1d) { // JAL or JALX 537 writeValue(loc, 0x1d << 26, 32, 0); 538 return val; 539 } 540 break; 541 } 542 case R_MICROMIPS_26_S1: { 543 uint32_t inst = readShuffle<e>(loc) >> 26; 544 if (inst == 0x3d || inst == 0x3c) { // JAL32 or JALX32 545 val >>= 1; 546 writeShuffleValue<e>(loc, 0x3c << 26, 32, 0); 547 return val; 548 } 549 break; 550 } 551 case R_MIPS_PC26_S2: 552 case R_MIPS_PC21_S2: 553 case R_MIPS_PC16: 554 case R_MICROMIPS_PC16_S1: 555 case R_MICROMIPS_PC10_S1: 556 case R_MICROMIPS_PC7_S1: 557 // FIXME (simon): Support valid branch relocations. 558 break; 559 default: 560 llvm_unreachable("unexpected jump/branch relocation"); 561 } 562 563 error(getErrorLocation(loc) + 564 "unsupported jump/branch instruction between ISA modes referenced by " + 565 toString(type) + " relocation"); 566 return val; 567 } 568 569 template <class ELFT> 570 void MIPS<ELFT>::relocate(uint8_t *loc, const Relocation &rel, 571 uint64_t val) const { 572 const endianness e = ELFT::TargetEndianness; 573 RelType type = rel.type; 574 575 if (ELFT::Is64Bits || config->mipsN32Abi) 576 std::tie(type, val) = calculateMipsRelChain(loc, type, val); 577 578 // Detect cross-mode jump/branch and fix instruction. 579 val = fixupCrossModeJump<ELFT>(loc, type, val); 580 581 // Thread pointer and DRP offsets from the start of TLS data area. 582 // https://www.linux-mips.org/wiki/NPTL 583 if (type == R_MIPS_TLS_DTPREL_HI16 || type == R_MIPS_TLS_DTPREL_LO16 || 584 type == R_MIPS_TLS_DTPREL32 || type == R_MIPS_TLS_DTPREL64 || 585 type == R_MICROMIPS_TLS_DTPREL_HI16 || 586 type == R_MICROMIPS_TLS_DTPREL_LO16) { 587 val -= 0x8000; 588 } 589 590 switch (type) { 591 case R_MIPS_32: 592 case R_MIPS_GPREL32: 593 case R_MIPS_TLS_DTPREL32: 594 case R_MIPS_TLS_TPREL32: 595 write32(loc, val); 596 break; 597 case R_MIPS_64: 598 case R_MIPS_TLS_DTPREL64: 599 case R_MIPS_TLS_TPREL64: 600 write64(loc, val); 601 break; 602 case R_MIPS_26: 603 writeValue(loc, val, 26, 2); 604 break; 605 case R_MIPS_GOT16: 606 // The R_MIPS_GOT16 relocation's value in "relocatable" linking mode 607 // is updated addend (not a GOT index). In that case write high 16 bits 608 // to store a correct addend value. 609 if (config->relocatable) { 610 writeValue(loc, val + 0x8000, 16, 16); 611 } else { 612 checkInt(loc, val, 16, rel); 613 writeValue(loc, val, 16, 0); 614 } 615 break; 616 case R_MICROMIPS_GOT16: 617 if (config->relocatable) { 618 writeShuffleValue<e>(loc, val + 0x8000, 16, 16); 619 } else { 620 checkInt(loc, val, 16, rel); 621 writeShuffleValue<e>(loc, val, 16, 0); 622 } 623 break; 624 case R_MIPS_CALL16: 625 case R_MIPS_GOT_DISP: 626 case R_MIPS_GOT_PAGE: 627 case R_MIPS_GPREL16: 628 case R_MIPS_TLS_GD: 629 case R_MIPS_TLS_GOTTPREL: 630 case R_MIPS_TLS_LDM: 631 checkInt(loc, val, 16, rel); 632 LLVM_FALLTHROUGH; 633 case R_MIPS_CALL_LO16: 634 case R_MIPS_GOT_LO16: 635 case R_MIPS_GOT_OFST: 636 case R_MIPS_LO16: 637 case R_MIPS_PCLO16: 638 case R_MIPS_TLS_DTPREL_LO16: 639 case R_MIPS_TLS_TPREL_LO16: 640 writeValue(loc, val, 16, 0); 641 break; 642 case R_MICROMIPS_GPREL16: 643 case R_MICROMIPS_TLS_GD: 644 case R_MICROMIPS_TLS_LDM: 645 checkInt(loc, val, 16, rel); 646 writeShuffleValue<e>(loc, val, 16, 0); 647 break; 648 case R_MICROMIPS_CALL16: 649 case R_MICROMIPS_CALL_LO16: 650 case R_MICROMIPS_LO16: 651 case R_MICROMIPS_TLS_DTPREL_LO16: 652 case R_MICROMIPS_TLS_GOTTPREL: 653 case R_MICROMIPS_TLS_TPREL_LO16: 654 writeShuffleValue<e>(loc, val, 16, 0); 655 break; 656 case R_MICROMIPS_GPREL7_S2: 657 checkInt(loc, val, 7, rel); 658 writeShuffleValue<e>(loc, val, 7, 2); 659 break; 660 case R_MIPS_CALL_HI16: 661 case R_MIPS_GOT_HI16: 662 case R_MIPS_HI16: 663 case R_MIPS_PCHI16: 664 case R_MIPS_TLS_DTPREL_HI16: 665 case R_MIPS_TLS_TPREL_HI16: 666 writeValue(loc, val + 0x8000, 16, 16); 667 break; 668 case R_MICROMIPS_CALL_HI16: 669 case R_MICROMIPS_GOT_HI16: 670 case R_MICROMIPS_HI16: 671 case R_MICROMIPS_TLS_DTPREL_HI16: 672 case R_MICROMIPS_TLS_TPREL_HI16: 673 writeShuffleValue<e>(loc, val + 0x8000, 16, 16); 674 break; 675 case R_MIPS_HIGHER: 676 writeValue(loc, val + 0x80008000, 16, 32); 677 break; 678 case R_MIPS_HIGHEST: 679 writeValue(loc, val + 0x800080008000, 16, 48); 680 break; 681 case R_MIPS_JALR: 682 val -= 4; 683 // Replace jalr/jr instructions by bal/b if the target 684 // offset fits into the 18-bit range. 685 if (isInt<18>(val)) { 686 switch (read32(loc)) { 687 case 0x0320f809: // jalr $25 => bal sym 688 write32(loc, 0x04110000 | ((val >> 2) & 0xffff)); 689 break; 690 case 0x03200008: // jr $25 => b sym 691 write32(loc, 0x10000000 | ((val >> 2) & 0xffff)); 692 break; 693 } 694 } 695 break; 696 case R_MICROMIPS_JALR: 697 // Ignore this optimization relocation for now 698 break; 699 case R_MIPS_PC16: 700 checkAlignment(loc, val, 4, rel); 701 checkInt(loc, val, 18, rel); 702 writeValue(loc, val, 16, 2); 703 break; 704 case R_MIPS_PC19_S2: 705 checkAlignment(loc, val, 4, rel); 706 checkInt(loc, val, 21, rel); 707 writeValue(loc, val, 19, 2); 708 break; 709 case R_MIPS_PC21_S2: 710 checkAlignment(loc, val, 4, rel); 711 checkInt(loc, val, 23, rel); 712 writeValue(loc, val, 21, 2); 713 break; 714 case R_MIPS_PC26_S2: 715 checkAlignment(loc, val, 4, rel); 716 checkInt(loc, val, 28, rel); 717 writeValue(loc, val, 26, 2); 718 break; 719 case R_MIPS_PC32: 720 writeValue(loc, val, 32, 0); 721 break; 722 case R_MICROMIPS_26_S1: 723 case R_MICROMIPS_PC26_S1: 724 checkInt(loc, val, 27, rel); 725 writeShuffleValue<e>(loc, val, 26, 1); 726 break; 727 case R_MICROMIPS_PC7_S1: 728 checkInt(loc, val, 8, rel); 729 writeMicroRelocation16<e>(loc, val, 7, 1); 730 break; 731 case R_MICROMIPS_PC10_S1: 732 checkInt(loc, val, 11, rel); 733 writeMicroRelocation16<e>(loc, val, 10, 1); 734 break; 735 case R_MICROMIPS_PC16_S1: 736 checkInt(loc, val, 17, rel); 737 writeShuffleValue<e>(loc, val, 16, 1); 738 break; 739 case R_MICROMIPS_PC18_S3: 740 checkInt(loc, val, 21, rel); 741 writeShuffleValue<e>(loc, val, 18, 3); 742 break; 743 case R_MICROMIPS_PC19_S2: 744 checkInt(loc, val, 21, rel); 745 writeShuffleValue<e>(loc, val, 19, 2); 746 break; 747 case R_MICROMIPS_PC21_S1: 748 checkInt(loc, val, 22, rel); 749 writeShuffleValue<e>(loc, val, 21, 1); 750 break; 751 case R_MICROMIPS_PC23_S2: 752 checkInt(loc, val, 25, rel); 753 writeShuffleValue<e>(loc, val, 23, 2); 754 break; 755 default: 756 llvm_unreachable("unknown relocation"); 757 } 758 } 759 760 template <class ELFT> bool MIPS<ELFT>::usesOnlyLowPageBits(RelType type) const { 761 return type == R_MIPS_LO16 || type == R_MIPS_GOT_OFST || 762 type == R_MICROMIPS_LO16; 763 } 764 765 // Return true if the symbol is a PIC function. 766 template <class ELFT> bool elf::isMipsPIC(const Defined *sym) { 767 if (!sym->isFunc()) 768 return false; 769 770 if (sym->stOther & STO_MIPS_PIC) 771 return true; 772 773 if (!sym->section) 774 return false; 775 776 ObjFile<ELFT> *file = 777 cast<InputSectionBase>(sym->section)->template getFile<ELFT>(); 778 if (!file) 779 return false; 780 781 return file->getObj().getHeader().e_flags & EF_MIPS_PIC; 782 } 783 784 template <class ELFT> TargetInfo *elf::getMipsTargetInfo() { 785 static MIPS<ELFT> target; 786 return ⌖ 787 } 788 789 template TargetInfo *elf::getMipsTargetInfo<ELF32LE>(); 790 template TargetInfo *elf::getMipsTargetInfo<ELF32BE>(); 791 template TargetInfo *elf::getMipsTargetInfo<ELF64LE>(); 792 template TargetInfo *elf::getMipsTargetInfo<ELF64BE>(); 793 794 template bool elf::isMipsPIC<ELF32LE>(const Defined *); 795 template bool elf::isMipsPIC<ELF32BE>(const Defined *); 796 template bool elf::isMipsPIC<ELF64LE>(const Defined *); 797 template bool elf::isMipsPIC<ELF64BE>(const Defined *); 798