1 //===--------------------------- DwarfParser.hpp --------------------------===// 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 // Parses DWARF CFIs (FDEs and CIEs). 9 // 10 //===----------------------------------------------------------------------===// 11 12 #ifndef __DWARF_PARSER_HPP__ 13 #define __DWARF_PARSER_HPP__ 14 15 #include <inttypes.h> 16 #include <stdint.h> 17 #include <stdio.h> 18 #include <stdlib.h> 19 20 #include "libunwind.h" 21 #include "dwarf2.h" 22 #include "Registers.hpp" 23 24 #include "config.h" 25 26 namespace libunwind { 27 28 /// CFI_Parser does basic parsing of a CFI (Call Frame Information) records. 29 /// See DWARF Spec for details: 30 /// http://refspecs.linuxbase.org/LSB_3.1.0/LSB-Core-generic/LSB-Core-generic/ehframechpt.html 31 /// 32 template <typename A> 33 class CFI_Parser { 34 public: 35 typedef typename A::pint_t pint_t; 36 37 /// Information encoded in a CIE (Common Information Entry) 38 struct CIE_Info { 39 pint_t cieStart; 40 pint_t cieLength; 41 pint_t cieInstructions; 42 uint8_t pointerEncoding; 43 uint8_t lsdaEncoding; 44 uint8_t personalityEncoding; 45 uint8_t personalityOffsetInCIE; 46 pint_t personality; 47 uint32_t codeAlignFactor; 48 int dataAlignFactor; 49 bool isSignalFrame; 50 bool fdesHaveAugmentationData; 51 uint8_t returnAddressRegister; 52 #if defined(_LIBUNWIND_TARGET_AARCH64) 53 bool addressesSignedWithBKey; 54 #endif 55 }; 56 57 /// Information about an FDE (Frame Description Entry) 58 struct FDE_Info { 59 pint_t fdeStart; 60 pint_t fdeLength; 61 pint_t fdeInstructions; 62 pint_t pcStart; 63 pint_t pcEnd; 64 pint_t lsda; 65 }; 66 67 enum { 68 kMaxRegisterNumber = _LIBUNWIND_HIGHEST_DWARF_REGISTER 69 }; 70 enum RegisterSavedWhere { 71 kRegisterUnused, 72 kRegisterInCFA, 73 kRegisterOffsetFromCFA, 74 kRegisterInRegister, 75 kRegisterAtExpression, 76 kRegisterIsExpression 77 }; 78 struct RegisterLocation { 79 RegisterSavedWhere location; 80 bool initialStateSaved; 81 int64_t value; 82 }; 83 /// Information about a frame layout and registers saved determined 84 /// by "running" the DWARF FDE "instructions" 85 struct PrologInfo { 86 uint32_t cfaRegister; 87 int32_t cfaRegisterOffset; // CFA = (cfaRegister)+cfaRegisterOffset 88 int64_t cfaExpression; // CFA = expression 89 uint32_t spExtraArgSize; 90 uint32_t codeOffsetAtStackDecrement; 91 bool registersInOtherRegisters; 92 bool sameValueUsed; 93 RegisterLocation savedRegisters[kMaxRegisterNumber + 1]; 94 enum class InitializeTime { kLazy, kNormal }; 95 96 // When saving registers, this data structure is lazily initialized. 97 PrologInfo(InitializeTime IT = InitializeTime::kNormal) { 98 if (IT == InitializeTime::kNormal) 99 memset(this, 0, sizeof(*this)); 100 } 101 void checkSaveRegister(uint64_t reg, PrologInfo &initialState) { 102 if (!savedRegisters[reg].initialStateSaved) { 103 initialState.savedRegisters[reg] = savedRegisters[reg]; 104 savedRegisters[reg].initialStateSaved = true; 105 } 106 } 107 void setRegister(uint64_t reg, RegisterSavedWhere newLocation, 108 int64_t newValue, PrologInfo &initialState) { 109 checkSaveRegister(reg, initialState); 110 savedRegisters[reg].location = newLocation; 111 savedRegisters[reg].value = newValue; 112 } 113 void setRegisterLocation(uint64_t reg, RegisterSavedWhere newLocation, 114 PrologInfo &initialState) { 115 checkSaveRegister(reg, initialState); 116 savedRegisters[reg].location = newLocation; 117 } 118 void setRegisterValue(uint64_t reg, int64_t newValue, 119 PrologInfo &initialState) { 120 checkSaveRegister(reg, initialState); 121 savedRegisters[reg].value = newValue; 122 } 123 void restoreRegisterToInitialState(uint64_t reg, PrologInfo &initialState) { 124 if (savedRegisters[reg].initialStateSaved) 125 savedRegisters[reg] = initialState.savedRegisters[reg]; 126 // else the register still holds its initial state 127 } 128 }; 129 130 struct PrologInfoStackEntry { 131 PrologInfoStackEntry(PrologInfoStackEntry *n, const PrologInfo &i) 132 : next(n), info(i) {} 133 PrologInfoStackEntry *next; 134 PrologInfo info; 135 }; 136 137 static bool findFDE(A &addressSpace, pint_t pc, pint_t ehSectionStart, 138 uint32_t sectionLength, pint_t fdeHint, FDE_Info *fdeInfo, 139 CIE_Info *cieInfo); 140 static const char *decodeFDE(A &addressSpace, pint_t fdeStart, 141 FDE_Info *fdeInfo, CIE_Info *cieInfo); 142 static bool parseFDEInstructions(A &addressSpace, const FDE_Info &fdeInfo, 143 const CIE_Info &cieInfo, pint_t upToPC, 144 int arch, PrologInfo *results); 145 146 static const char *parseCIE(A &addressSpace, pint_t cie, CIE_Info *cieInfo); 147 148 private: 149 static bool parseInstructions(A &addressSpace, pint_t instructions, 150 pint_t instructionsEnd, const CIE_Info &cieInfo, 151 pint_t pcoffset, 152 PrologInfoStackEntry *&rememberStack, int arch, 153 PrologInfo *results); 154 }; 155 156 /// Parse a FDE into a CIE_Info and an FDE_Info 157 template <typename A> 158 const char *CFI_Parser<A>::decodeFDE(A &addressSpace, pint_t fdeStart, 159 FDE_Info *fdeInfo, CIE_Info *cieInfo) { 160 pint_t p = fdeStart; 161 pint_t cfiLength = (pint_t)addressSpace.get32(p); 162 p += 4; 163 if (cfiLength == 0xffffffff) { 164 // 0xffffffff means length is really next 8 bytes 165 cfiLength = (pint_t)addressSpace.get64(p); 166 p += 8; 167 } 168 if (cfiLength == 0) 169 return "FDE has zero length"; // end marker 170 uint32_t ciePointer = addressSpace.get32(p); 171 if (ciePointer == 0) 172 return "FDE is really a CIE"; // this is a CIE not an FDE 173 pint_t nextCFI = p + cfiLength; 174 pint_t cieStart = p - ciePointer; 175 const char *err = parseCIE(addressSpace, cieStart, cieInfo); 176 if (err != NULL) 177 return err; 178 p += 4; 179 // Parse pc begin and range. 180 pint_t pcStart = 181 addressSpace.getEncodedP(p, nextCFI, cieInfo->pointerEncoding); 182 pint_t pcRange = 183 addressSpace.getEncodedP(p, nextCFI, cieInfo->pointerEncoding & 0x0F); 184 // Parse rest of info. 185 fdeInfo->lsda = 0; 186 // Check for augmentation length. 187 if (cieInfo->fdesHaveAugmentationData) { 188 pint_t augLen = (pint_t)addressSpace.getULEB128(p, nextCFI); 189 pint_t endOfAug = p + augLen; 190 if (cieInfo->lsdaEncoding != DW_EH_PE_omit) { 191 // Peek at value (without indirection). Zero means no LSDA. 192 pint_t lsdaStart = p; 193 if (addressSpace.getEncodedP(p, nextCFI, cieInfo->lsdaEncoding & 0x0F) != 194 0) { 195 // Reset pointer and re-parse LSDA address. 196 p = lsdaStart; 197 fdeInfo->lsda = 198 addressSpace.getEncodedP(p, nextCFI, cieInfo->lsdaEncoding); 199 } 200 } 201 p = endOfAug; 202 } 203 fdeInfo->fdeStart = fdeStart; 204 fdeInfo->fdeLength = nextCFI - fdeStart; 205 fdeInfo->fdeInstructions = p; 206 fdeInfo->pcStart = pcStart; 207 fdeInfo->pcEnd = pcStart + pcRange; 208 return NULL; // success 209 } 210 211 /// Scan an eh_frame section to find an FDE for a pc 212 template <typename A> 213 bool CFI_Parser<A>::findFDE(A &addressSpace, pint_t pc, pint_t ehSectionStart, 214 uint32_t sectionLength, pint_t fdeHint, 215 FDE_Info *fdeInfo, CIE_Info *cieInfo) { 216 //fprintf(stderr, "findFDE(0x%llX)\n", (long long)pc); 217 pint_t p = (fdeHint != 0) ? fdeHint : ehSectionStart; 218 const pint_t ehSectionEnd = p + sectionLength; 219 while (p < ehSectionEnd) { 220 pint_t currentCFI = p; 221 //fprintf(stderr, "findFDE() CFI at 0x%llX\n", (long long)p); 222 pint_t cfiLength = addressSpace.get32(p); 223 p += 4; 224 if (cfiLength == 0xffffffff) { 225 // 0xffffffff means length is really next 8 bytes 226 cfiLength = (pint_t)addressSpace.get64(p); 227 p += 8; 228 } 229 if (cfiLength == 0) 230 return false; // end marker 231 uint32_t id = addressSpace.get32(p); 232 if (id == 0) { 233 // Skip over CIEs. 234 p += cfiLength; 235 } else { 236 // Process FDE to see if it covers pc. 237 pint_t nextCFI = p + cfiLength; 238 uint32_t ciePointer = addressSpace.get32(p); 239 pint_t cieStart = p - ciePointer; 240 // Validate pointer to CIE is within section. 241 if ((ehSectionStart <= cieStart) && (cieStart < ehSectionEnd)) { 242 if (parseCIE(addressSpace, cieStart, cieInfo) == NULL) { 243 p += 4; 244 // Parse pc begin and range. 245 pint_t pcStart = 246 addressSpace.getEncodedP(p, nextCFI, cieInfo->pointerEncoding); 247 pint_t pcRange = addressSpace.getEncodedP( 248 p, nextCFI, cieInfo->pointerEncoding & 0x0F); 249 // Test if pc is within the function this FDE covers. 250 if ((pcStart < pc) && (pc <= pcStart + pcRange)) { 251 // parse rest of info 252 fdeInfo->lsda = 0; 253 // check for augmentation length 254 if (cieInfo->fdesHaveAugmentationData) { 255 pint_t augLen = (pint_t)addressSpace.getULEB128(p, nextCFI); 256 pint_t endOfAug = p + augLen; 257 if (cieInfo->lsdaEncoding != DW_EH_PE_omit) { 258 // Peek at value (without indirection). Zero means no LSDA. 259 pint_t lsdaStart = p; 260 if (addressSpace.getEncodedP( 261 p, nextCFI, cieInfo->lsdaEncoding & 0x0F) != 0) { 262 // Reset pointer and re-parse LSDA address. 263 p = lsdaStart; 264 fdeInfo->lsda = addressSpace 265 .getEncodedP(p, nextCFI, cieInfo->lsdaEncoding); 266 } 267 } 268 p = endOfAug; 269 } 270 fdeInfo->fdeStart = currentCFI; 271 fdeInfo->fdeLength = nextCFI - currentCFI; 272 fdeInfo->fdeInstructions = p; 273 fdeInfo->pcStart = pcStart; 274 fdeInfo->pcEnd = pcStart + pcRange; 275 return true; 276 } else { 277 // pc is not in begin/range, skip this FDE 278 } 279 } else { 280 // Malformed CIE, now augmentation describing pc range encoding. 281 } 282 } else { 283 // malformed FDE. CIE is bad 284 } 285 p = nextCFI; 286 } 287 } 288 return false; 289 } 290 291 /// Extract info from a CIE 292 template <typename A> 293 const char *CFI_Parser<A>::parseCIE(A &addressSpace, pint_t cie, 294 CIE_Info *cieInfo) { 295 cieInfo->pointerEncoding = 0; 296 cieInfo->lsdaEncoding = DW_EH_PE_omit; 297 cieInfo->personalityEncoding = 0; 298 cieInfo->personalityOffsetInCIE = 0; 299 cieInfo->personality = 0; 300 cieInfo->codeAlignFactor = 0; 301 cieInfo->dataAlignFactor = 0; 302 cieInfo->isSignalFrame = false; 303 cieInfo->fdesHaveAugmentationData = false; 304 #if defined(_LIBUNWIND_TARGET_AARCH64) 305 cieInfo->addressesSignedWithBKey = false; 306 #endif 307 cieInfo->cieStart = cie; 308 pint_t p = cie; 309 pint_t cieLength = (pint_t)addressSpace.get32(p); 310 p += 4; 311 pint_t cieContentEnd = p + cieLength; 312 if (cieLength == 0xffffffff) { 313 // 0xffffffff means length is really next 8 bytes 314 cieLength = (pint_t)addressSpace.get64(p); 315 p += 8; 316 cieContentEnd = p + cieLength; 317 } 318 if (cieLength == 0) 319 return NULL; 320 // CIE ID is always 0 321 if (addressSpace.get32(p) != 0) 322 return "CIE ID is not zero"; 323 p += 4; 324 // Version is always 1 or 3 325 uint8_t version = addressSpace.get8(p); 326 if ((version != 1) && (version != 3)) 327 return "CIE version is not 1 or 3"; 328 ++p; 329 // save start of augmentation string and find end 330 pint_t strStart = p; 331 while (addressSpace.get8(p) != 0) 332 ++p; 333 ++p; 334 // parse code aligment factor 335 cieInfo->codeAlignFactor = (uint32_t)addressSpace.getULEB128(p, cieContentEnd); 336 // parse data alignment factor 337 cieInfo->dataAlignFactor = (int)addressSpace.getSLEB128(p, cieContentEnd); 338 // parse return address register 339 uint64_t raReg = addressSpace.getULEB128(p, cieContentEnd); 340 assert(raReg < 255 && "return address register too large"); 341 cieInfo->returnAddressRegister = (uint8_t)raReg; 342 // parse augmentation data based on augmentation string 343 const char *result = NULL; 344 if (addressSpace.get8(strStart) == 'z') { 345 // parse augmentation data length 346 addressSpace.getULEB128(p, cieContentEnd); 347 for (pint_t s = strStart; addressSpace.get8(s) != '\0'; ++s) { 348 switch (addressSpace.get8(s)) { 349 case 'z': 350 cieInfo->fdesHaveAugmentationData = true; 351 break; 352 case 'P': 353 cieInfo->personalityEncoding = addressSpace.get8(p); 354 ++p; 355 cieInfo->personalityOffsetInCIE = (uint8_t)(p - cie); 356 cieInfo->personality = addressSpace 357 .getEncodedP(p, cieContentEnd, cieInfo->personalityEncoding); 358 break; 359 case 'L': 360 cieInfo->lsdaEncoding = addressSpace.get8(p); 361 ++p; 362 break; 363 case 'R': 364 cieInfo->pointerEncoding = addressSpace.get8(p); 365 ++p; 366 break; 367 case 'S': 368 cieInfo->isSignalFrame = true; 369 break; 370 #if defined(_LIBUNWIND_TARGET_AARCH64) 371 case 'B': 372 cieInfo->addressesSignedWithBKey = true; 373 break; 374 #endif 375 default: 376 // ignore unknown letters 377 break; 378 } 379 } 380 } 381 cieInfo->cieLength = cieContentEnd - cieInfo->cieStart; 382 cieInfo->cieInstructions = p; 383 return result; 384 } 385 386 387 /// "run" the DWARF instructions and create the abstact PrologInfo for an FDE 388 template <typename A> 389 bool CFI_Parser<A>::parseFDEInstructions(A &addressSpace, 390 const FDE_Info &fdeInfo, 391 const CIE_Info &cieInfo, pint_t upToPC, 392 int arch, PrologInfo *results) { 393 PrologInfoStackEntry *rememberStack = NULL; 394 395 // parse CIE then FDE instructions 396 bool returnValue = 397 parseInstructions(addressSpace, cieInfo.cieInstructions, 398 cieInfo.cieStart + cieInfo.cieLength, cieInfo, 399 (pint_t)(-1), rememberStack, arch, results) && 400 parseInstructions(addressSpace, fdeInfo.fdeInstructions, 401 fdeInfo.fdeStart + fdeInfo.fdeLength, cieInfo, 402 upToPC - fdeInfo.pcStart, rememberStack, arch, results); 403 404 // Clean up rememberStack. Even in the case where every DW_CFA_remember_state 405 // is paired with a DW_CFA_restore_state, parseInstructions can skip restore 406 // opcodes if it reaches the target PC and stops interpreting, so we have to 407 // make sure we don't leak memory. 408 while (rememberStack) { 409 PrologInfoStackEntry *next = rememberStack->next; 410 free(rememberStack); 411 rememberStack = next; 412 } 413 414 return returnValue; 415 } 416 417 /// "run" the DWARF instructions 418 template <typename A> 419 bool CFI_Parser<A>::parseInstructions(A &addressSpace, pint_t instructions, 420 pint_t instructionsEnd, 421 const CIE_Info &cieInfo, pint_t pcoffset, 422 PrologInfoStackEntry *&rememberStack, 423 int arch, PrologInfo *results) { 424 pint_t p = instructions; 425 pint_t codeOffset = 0; 426 // initialState initialized as registers in results are modified. Use 427 // PrologInfo accessor functions to avoid reading uninitialized data. 428 PrologInfo initialState(PrologInfo::InitializeTime::kLazy); 429 430 _LIBUNWIND_TRACE_DWARF("parseInstructions(instructions=0x%0" PRIx64 ")\n", 431 static_cast<uint64_t>(instructionsEnd)); 432 433 // see DWARF Spec, section 6.4.2 for details on unwind opcodes 434 while ((p < instructionsEnd) && (codeOffset < pcoffset)) { 435 uint64_t reg; 436 uint64_t reg2; 437 int64_t offset; 438 uint64_t length; 439 uint8_t opcode = addressSpace.get8(p); 440 uint8_t operand; 441 #if !defined(_LIBUNWIND_NO_HEAP) 442 PrologInfoStackEntry *entry; 443 #endif 444 ++p; 445 switch (opcode) { 446 case DW_CFA_nop: 447 _LIBUNWIND_TRACE_DWARF("DW_CFA_nop\n"); 448 break; 449 case DW_CFA_set_loc: 450 codeOffset = 451 addressSpace.getEncodedP(p, instructionsEnd, cieInfo.pointerEncoding); 452 _LIBUNWIND_TRACE_DWARF("DW_CFA_set_loc\n"); 453 break; 454 case DW_CFA_advance_loc1: 455 codeOffset += (addressSpace.get8(p) * cieInfo.codeAlignFactor); 456 p += 1; 457 _LIBUNWIND_TRACE_DWARF("DW_CFA_advance_loc1: new offset=%" PRIu64 "\n", 458 static_cast<uint64_t>(codeOffset)); 459 break; 460 case DW_CFA_advance_loc2: 461 codeOffset += (addressSpace.get16(p) * cieInfo.codeAlignFactor); 462 p += 2; 463 _LIBUNWIND_TRACE_DWARF("DW_CFA_advance_loc2: new offset=%" PRIu64 "\n", 464 static_cast<uint64_t>(codeOffset)); 465 break; 466 case DW_CFA_advance_loc4: 467 codeOffset += (addressSpace.get32(p) * cieInfo.codeAlignFactor); 468 p += 4; 469 _LIBUNWIND_TRACE_DWARF("DW_CFA_advance_loc4: new offset=%" PRIu64 "\n", 470 static_cast<uint64_t>(codeOffset)); 471 break; 472 case DW_CFA_offset_extended: 473 reg = addressSpace.getULEB128(p, instructionsEnd); 474 offset = (int64_t)addressSpace.getULEB128(p, instructionsEnd) 475 * cieInfo.dataAlignFactor; 476 if (reg > kMaxRegisterNumber) { 477 _LIBUNWIND_LOG0( 478 "malformed DW_CFA_offset_extended DWARF unwind, reg too big"); 479 return false; 480 } 481 results->setRegister(reg, kRegisterInCFA, offset, initialState); 482 _LIBUNWIND_TRACE_DWARF("DW_CFA_offset_extended(reg=%" PRIu64 ", " 483 "offset=%" PRId64 ")\n", 484 reg, offset); 485 break; 486 case DW_CFA_restore_extended: 487 reg = addressSpace.getULEB128(p, instructionsEnd); 488 if (reg > kMaxRegisterNumber) { 489 _LIBUNWIND_LOG0( 490 "malformed DW_CFA_restore_extended DWARF unwind, reg too big"); 491 return false; 492 } 493 results->restoreRegisterToInitialState(reg, initialState); 494 _LIBUNWIND_TRACE_DWARF("DW_CFA_restore_extended(reg=%" PRIu64 ")\n", reg); 495 break; 496 case DW_CFA_undefined: 497 reg = addressSpace.getULEB128(p, instructionsEnd); 498 if (reg > kMaxRegisterNumber) { 499 _LIBUNWIND_LOG0( 500 "malformed DW_CFA_undefined DWARF unwind, reg too big"); 501 return false; 502 } 503 results->setRegisterLocation(reg, kRegisterUnused, initialState); 504 _LIBUNWIND_TRACE_DWARF("DW_CFA_undefined(reg=%" PRIu64 ")\n", reg); 505 break; 506 case DW_CFA_same_value: 507 reg = addressSpace.getULEB128(p, instructionsEnd); 508 if (reg > kMaxRegisterNumber) { 509 _LIBUNWIND_LOG0( 510 "malformed DW_CFA_same_value DWARF unwind, reg too big"); 511 return false; 512 } 513 // <rdar://problem/8456377> DW_CFA_same_value unsupported 514 // "same value" means register was stored in frame, but its current 515 // value has not changed, so no need to restore from frame. 516 // We model this as if the register was never saved. 517 results->setRegisterLocation(reg, kRegisterUnused, initialState); 518 // set flag to disable conversion to compact unwind 519 results->sameValueUsed = true; 520 _LIBUNWIND_TRACE_DWARF("DW_CFA_same_value(reg=%" PRIu64 ")\n", reg); 521 break; 522 case DW_CFA_register: 523 reg = addressSpace.getULEB128(p, instructionsEnd); 524 reg2 = addressSpace.getULEB128(p, instructionsEnd); 525 if (reg > kMaxRegisterNumber) { 526 _LIBUNWIND_LOG0( 527 "malformed DW_CFA_register DWARF unwind, reg too big"); 528 return false; 529 } 530 if (reg2 > kMaxRegisterNumber) { 531 _LIBUNWIND_LOG0( 532 "malformed DW_CFA_register DWARF unwind, reg2 too big"); 533 return false; 534 } 535 results->setRegister(reg, kRegisterInRegister, (int64_t)reg2, 536 initialState); 537 // set flag to disable conversion to compact unwind 538 results->registersInOtherRegisters = true; 539 _LIBUNWIND_TRACE_DWARF( 540 "DW_CFA_register(reg=%" PRIu64 ", reg2=%" PRIu64 ")\n", reg, reg2); 541 break; 542 #if !defined(_LIBUNWIND_NO_HEAP) 543 case DW_CFA_remember_state: 544 // avoid operator new, because that would be an upward dependency 545 entry = (PrologInfoStackEntry *)malloc(sizeof(PrologInfoStackEntry)); 546 if (entry != NULL) { 547 entry->next = rememberStack; 548 entry->info = *results; 549 rememberStack = entry; 550 } else { 551 return false; 552 } 553 _LIBUNWIND_TRACE_DWARF("DW_CFA_remember_state\n"); 554 break; 555 case DW_CFA_restore_state: 556 if (rememberStack != NULL) { 557 PrologInfoStackEntry *top = rememberStack; 558 *results = top->info; 559 rememberStack = top->next; 560 free((char *)top); 561 } else { 562 return false; 563 } 564 _LIBUNWIND_TRACE_DWARF("DW_CFA_restore_state\n"); 565 break; 566 #endif 567 case DW_CFA_def_cfa: 568 reg = addressSpace.getULEB128(p, instructionsEnd); 569 offset = (int64_t)addressSpace.getULEB128(p, instructionsEnd); 570 if (reg > kMaxRegisterNumber) { 571 _LIBUNWIND_LOG0("malformed DW_CFA_def_cfa DWARF unwind, reg too big"); 572 return false; 573 } 574 results->cfaRegister = (uint32_t)reg; 575 results->cfaRegisterOffset = (int32_t)offset; 576 _LIBUNWIND_TRACE_DWARF( 577 "DW_CFA_def_cfa(reg=%" PRIu64 ", offset=%" PRIu64 ")\n", reg, offset); 578 break; 579 case DW_CFA_def_cfa_register: 580 reg = addressSpace.getULEB128(p, instructionsEnd); 581 if (reg > kMaxRegisterNumber) { 582 _LIBUNWIND_LOG0( 583 "malformed DW_CFA_def_cfa_register DWARF unwind, reg too big"); 584 return false; 585 } 586 results->cfaRegister = (uint32_t)reg; 587 _LIBUNWIND_TRACE_DWARF("DW_CFA_def_cfa_register(%" PRIu64 ")\n", reg); 588 break; 589 case DW_CFA_def_cfa_offset: 590 results->cfaRegisterOffset = (int32_t) 591 addressSpace.getULEB128(p, instructionsEnd); 592 results->codeOffsetAtStackDecrement = (uint32_t)codeOffset; 593 _LIBUNWIND_TRACE_DWARF("DW_CFA_def_cfa_offset(%d)\n", 594 results->cfaRegisterOffset); 595 break; 596 case DW_CFA_def_cfa_expression: 597 results->cfaRegister = 0; 598 results->cfaExpression = (int64_t)p; 599 length = addressSpace.getULEB128(p, instructionsEnd); 600 assert(length < static_cast<pint_t>(~0) && "pointer overflow"); 601 p += static_cast<pint_t>(length); 602 _LIBUNWIND_TRACE_DWARF("DW_CFA_def_cfa_expression(expression=0x%" PRIx64 603 ", length=%" PRIu64 ")\n", 604 results->cfaExpression, length); 605 break; 606 case DW_CFA_expression: 607 reg = addressSpace.getULEB128(p, instructionsEnd); 608 if (reg > kMaxRegisterNumber) { 609 _LIBUNWIND_LOG0( 610 "malformed DW_CFA_expression DWARF unwind, reg too big"); 611 return false; 612 } 613 results->setRegister(reg, kRegisterAtExpression, (int64_t)p, 614 initialState); 615 length = addressSpace.getULEB128(p, instructionsEnd); 616 assert(length < static_cast<pint_t>(~0) && "pointer overflow"); 617 p += static_cast<pint_t>(length); 618 _LIBUNWIND_TRACE_DWARF("DW_CFA_expression(reg=%" PRIu64 ", " 619 "expression=0x%" PRIx64 ", " 620 "length=%" PRIu64 ")\n", 621 reg, results->savedRegisters[reg].value, length); 622 break; 623 case DW_CFA_offset_extended_sf: 624 reg = addressSpace.getULEB128(p, instructionsEnd); 625 if (reg > kMaxRegisterNumber) { 626 _LIBUNWIND_LOG0( 627 "malformed DW_CFA_offset_extended_sf DWARF unwind, reg too big"); 628 return false; 629 } 630 offset = 631 addressSpace.getSLEB128(p, instructionsEnd) * cieInfo.dataAlignFactor; 632 results->setRegister(reg, kRegisterInCFA, offset, initialState); 633 _LIBUNWIND_TRACE_DWARF("DW_CFA_offset_extended_sf(reg=%" PRIu64 ", " 634 "offset=%" PRId64 ")\n", 635 reg, offset); 636 break; 637 case DW_CFA_def_cfa_sf: 638 reg = addressSpace.getULEB128(p, instructionsEnd); 639 offset = 640 addressSpace.getSLEB128(p, instructionsEnd) * cieInfo.dataAlignFactor; 641 if (reg > kMaxRegisterNumber) { 642 _LIBUNWIND_LOG0( 643 "malformed DW_CFA_def_cfa_sf DWARF unwind, reg too big"); 644 return false; 645 } 646 results->cfaRegister = (uint32_t)reg; 647 results->cfaRegisterOffset = (int32_t)offset; 648 _LIBUNWIND_TRACE_DWARF("DW_CFA_def_cfa_sf(reg=%" PRIu64 ", " 649 "offset=%" PRId64 ")\n", 650 reg, offset); 651 break; 652 case DW_CFA_def_cfa_offset_sf: 653 results->cfaRegisterOffset = (int32_t) 654 (addressSpace.getSLEB128(p, instructionsEnd) * cieInfo.dataAlignFactor); 655 results->codeOffsetAtStackDecrement = (uint32_t)codeOffset; 656 _LIBUNWIND_TRACE_DWARF("DW_CFA_def_cfa_offset_sf(%d)\n", 657 results->cfaRegisterOffset); 658 break; 659 case DW_CFA_val_offset: 660 reg = addressSpace.getULEB128(p, instructionsEnd); 661 if (reg > kMaxRegisterNumber) { 662 _LIBUNWIND_LOG( 663 "malformed DW_CFA_val_offset DWARF unwind, reg (%" PRIu64 664 ") out of range\n", 665 reg); 666 return false; 667 } 668 offset = (int64_t)addressSpace.getULEB128(p, instructionsEnd) 669 * cieInfo.dataAlignFactor; 670 results->setRegister(reg, kRegisterOffsetFromCFA, offset, initialState); 671 _LIBUNWIND_TRACE_DWARF("DW_CFA_val_offset(reg=%" PRIu64 ", " 672 "offset=%" PRId64 "\n", 673 reg, offset); 674 break; 675 case DW_CFA_val_offset_sf: 676 reg = addressSpace.getULEB128(p, instructionsEnd); 677 if (reg > kMaxRegisterNumber) { 678 _LIBUNWIND_LOG0( 679 "malformed DW_CFA_val_offset_sf DWARF unwind, reg too big"); 680 return false; 681 } 682 offset = 683 addressSpace.getSLEB128(p, instructionsEnd) * cieInfo.dataAlignFactor; 684 results->setRegister(reg, kRegisterOffsetFromCFA, offset, initialState); 685 _LIBUNWIND_TRACE_DWARF("DW_CFA_val_offset_sf(reg=%" PRIu64 ", " 686 "offset=%" PRId64 "\n", 687 reg, offset); 688 break; 689 case DW_CFA_val_expression: 690 reg = addressSpace.getULEB128(p, instructionsEnd); 691 if (reg > kMaxRegisterNumber) { 692 _LIBUNWIND_LOG0( 693 "malformed DW_CFA_val_expression DWARF unwind, reg too big"); 694 return false; 695 } 696 results->setRegister(reg, kRegisterIsExpression, (int64_t)p, 697 initialState); 698 length = addressSpace.getULEB128(p, instructionsEnd); 699 assert(length < static_cast<pint_t>(~0) && "pointer overflow"); 700 p += static_cast<pint_t>(length); 701 _LIBUNWIND_TRACE_DWARF("DW_CFA_val_expression(reg=%" PRIu64 ", " 702 "expression=0x%" PRIx64 ", length=%" PRIu64 ")\n", 703 reg, results->savedRegisters[reg].value, length); 704 break; 705 case DW_CFA_GNU_args_size: 706 length = addressSpace.getULEB128(p, instructionsEnd); 707 results->spExtraArgSize = (uint32_t)length; 708 _LIBUNWIND_TRACE_DWARF("DW_CFA_GNU_args_size(%" PRIu64 ")\n", length); 709 break; 710 case DW_CFA_GNU_negative_offset_extended: 711 reg = addressSpace.getULEB128(p, instructionsEnd); 712 if (reg > kMaxRegisterNumber) { 713 _LIBUNWIND_LOG0("malformed DW_CFA_GNU_negative_offset_extended DWARF " 714 "unwind, reg too big"); 715 return false; 716 } 717 offset = (int64_t)addressSpace.getULEB128(p, instructionsEnd) 718 * cieInfo.dataAlignFactor; 719 results->setRegister(reg, kRegisterInCFA, -offset, initialState); 720 _LIBUNWIND_TRACE_DWARF( 721 "DW_CFA_GNU_negative_offset_extended(%" PRId64 ")\n", offset); 722 break; 723 724 #if defined(_LIBUNWIND_TARGET_AARCH64) || defined(_LIBUNWIND_TARGET_SPARC) 725 // The same constant is used to represent different instructions on 726 // AArch64 (negate_ra_state) and SPARC (window_save). 727 static_assert(DW_CFA_AARCH64_negate_ra_state == DW_CFA_GNU_window_save, 728 "uses the same constant"); 729 case DW_CFA_AARCH64_negate_ra_state: 730 switch (arch) { 731 #if defined(_LIBUNWIND_TARGET_AARCH64) 732 case REGISTERS_ARM64: { 733 int64_t value = 734 results->savedRegisters[UNW_ARM64_RA_SIGN_STATE].value ^ 0x1; 735 results->setRegisterValue(UNW_ARM64_RA_SIGN_STATE, value, initialState); 736 _LIBUNWIND_TRACE_DWARF("DW_CFA_AARCH64_negate_ra_state\n"); 737 } break; 738 #endif 739 740 #if defined(_LIBUNWIND_TARGET_SPARC) 741 // case DW_CFA_GNU_window_save: 742 case REGISTERS_SPARC: 743 _LIBUNWIND_TRACE_DWARF("DW_CFA_GNU_window_save()\n"); 744 for (reg = UNW_SPARC_O0; reg <= UNW_SPARC_O7; reg++) { 745 results->setRegister(reg, kRegisterInRegister, 746 ((int64_t)reg - UNW_SPARC_O0) + UNW_SPARC_I0, 747 initialState); 748 } 749 750 for (reg = UNW_SPARC_L0; reg <= UNW_SPARC_I7; reg++) { 751 results->setRegister(reg, kRegisterInCFA, 752 ((int64_t)reg - UNW_SPARC_L0) * 4, initialState); 753 } 754 break; 755 #endif 756 } 757 break; 758 #else 759 (void)arch; 760 #endif 761 762 default: 763 operand = opcode & 0x3F; 764 switch (opcode & 0xC0) { 765 case DW_CFA_offset: 766 reg = operand; 767 if (reg > kMaxRegisterNumber) { 768 _LIBUNWIND_LOG("malformed DW_CFA_offset DWARF unwind, reg (%" PRIu64 769 ") out of range", 770 reg); 771 return false; 772 } 773 offset = (int64_t)addressSpace.getULEB128(p, instructionsEnd) 774 * cieInfo.dataAlignFactor; 775 results->setRegister(reg, kRegisterInCFA, offset, initialState); 776 _LIBUNWIND_TRACE_DWARF("DW_CFA_offset(reg=%d, offset=%" PRId64 ")\n", 777 operand, offset); 778 break; 779 case DW_CFA_advance_loc: 780 codeOffset += operand * cieInfo.codeAlignFactor; 781 _LIBUNWIND_TRACE_DWARF("DW_CFA_advance_loc: new offset=%" PRIu64 "\n", 782 static_cast<uint64_t>(codeOffset)); 783 break; 784 case DW_CFA_restore: 785 reg = operand; 786 if (reg > kMaxRegisterNumber) { 787 _LIBUNWIND_LOG("malformed DW_CFA_restore DWARF unwind, reg (%" PRIu64 788 ") out of range", 789 reg); 790 return false; 791 } 792 results->restoreRegisterToInitialState(reg, initialState); 793 _LIBUNWIND_TRACE_DWARF("DW_CFA_restore(reg=%" PRIu64 ")\n", 794 static_cast<uint64_t>(operand)); 795 break; 796 default: 797 _LIBUNWIND_TRACE_DWARF("unknown CFA opcode 0x%02X\n", opcode); 798 return false; 799 } 800 } 801 } 802 803 return true; 804 } 805 806 } // namespace libunwind 807 808 #endif // __DWARF_PARSER_HPP__ 809