1 //===--------------------------- DwarfParser.hpp --------------------------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is dual licensed under the MIT and the University of Illinois Open 6 // Source Licenses. See LICENSE.TXT for details. 7 // 8 // 9 // Parses DWARF CFIs (FDEs and CIEs). 10 // 11 //===----------------------------------------------------------------------===// 12 13 #ifndef __DWARF_PARSER_HPP__ 14 #define __DWARF_PARSER_HPP__ 15 16 #include <stdint.h> 17 #include <stdio.h> 18 #include <stdlib.h> 19 20 #include <vector> 21 22 #include "libunwind.h" 23 #include "dwarf2.h" 24 25 #include "AddressSpace.hpp" 26 27 namespace libunwind { 28 29 /// CFI_Parser does basic parsing of a CFI (Call Frame Information) records. 30 /// See Dwarf Spec for details: 31 /// http://refspecs.linuxbase.org/LSB_3.1.0/LSB-Core-generic/LSB-Core-generic/ehframechpt.html 32 /// 33 template <typename A> 34 class CFI_Parser { 35 public: 36 typedef typename A::pint_t pint_t; 37 38 /// Information encoded in a CIE (Common Information Entry) 39 struct CIE_Info { 40 pint_t cieStart; 41 pint_t cieLength; 42 pint_t cieInstructions; 43 uint8_t pointerEncoding; 44 uint8_t lsdaEncoding; 45 uint8_t personalityEncoding; 46 uint8_t personalityOffsetInCIE; 47 pint_t personality; 48 uint32_t codeAlignFactor; 49 int dataAlignFactor; 50 bool isSignalFrame; 51 bool fdesHaveAugmentationData; 52 uint8_t returnAddressRegister; 53 }; 54 55 /// Information about an FDE (Frame Description Entry) 56 struct FDE_Info { 57 pint_t fdeStart; 58 pint_t fdeLength; 59 pint_t fdeInstructions; 60 pint_t pcStart; 61 pint_t pcEnd; 62 pint_t lsda; 63 }; 64 65 enum { 66 kMaxRegisterNumber = 120 67 }; 68 enum RegisterSavedWhere { 69 kRegisterUnused, 70 kRegisterInCFA, 71 kRegisterOffsetFromCFA, 72 kRegisterInRegister, 73 kRegisterAtExpression, 74 kRegisterIsExpression 75 }; 76 struct RegisterLocation { 77 RegisterSavedWhere location; 78 int64_t value; 79 }; 80 /// Information about a frame layout and registers saved determined 81 /// by "running" the dwarf FDE "instructions" 82 struct PrologInfo { 83 uint32_t cfaRegister; 84 int32_t cfaRegisterOffset; // CFA = (cfaRegister)+cfaRegisterOffset 85 int64_t cfaExpression; // CFA = expression 86 uint32_t spExtraArgSize; 87 uint32_t codeOffsetAtStackDecrement; 88 bool registersInOtherRegisters; 89 bool sameValueUsed; 90 RegisterLocation savedRegisters[kMaxRegisterNumber]; 91 }; 92 93 struct PrologInfoStackEntry { 94 PrologInfoStackEntry(PrologInfoStackEntry *n, const PrologInfo &i) 95 : next(n), info(i) {} 96 PrologInfoStackEntry *next; 97 PrologInfo info; 98 }; 99 100 static bool findFDE(A &addressSpace, pint_t pc, pint_t ehSectionStart, 101 uint32_t sectionLength, pint_t fdeHint, FDE_Info *fdeInfo, 102 CIE_Info *cieInfo); 103 static const char *decodeFDE(A &addressSpace, pint_t fdeStart, 104 FDE_Info *fdeInfo, CIE_Info *cieInfo); 105 static bool parseFDEInstructions(A &addressSpace, const FDE_Info &fdeInfo, 106 const CIE_Info &cieInfo, pint_t upToPC, 107 PrologInfo *results); 108 109 static const char *parseCIE(A &addressSpace, pint_t cie, CIE_Info *cieInfo); 110 111 private: 112 static bool parseInstructions(A &addressSpace, pint_t instructions, 113 pint_t instructionsEnd, const CIE_Info &cieInfo, 114 pint_t pcoffset, 115 PrologInfoStackEntry *&rememberStack, 116 PrologInfo *results); 117 }; 118 119 /// Parse a FDE into a CIE_Info and an FDE_Info 120 template <typename A> 121 const char *CFI_Parser<A>::decodeFDE(A &addressSpace, pint_t fdeStart, 122 FDE_Info *fdeInfo, CIE_Info *cieInfo) { 123 pint_t p = fdeStart; 124 pint_t cfiLength = (pint_t)addressSpace.get32(p); 125 p += 4; 126 if (cfiLength == 0xffffffff) { 127 // 0xffffffff means length is really next 8 bytes 128 cfiLength = (pint_t)addressSpace.get64(p); 129 p += 8; 130 } 131 if (cfiLength == 0) 132 return "FDE has zero length"; // end marker 133 uint32_t ciePointer = addressSpace.get32(p); 134 if (ciePointer == 0) 135 return "FDE is really a CIE"; // this is a CIE not an FDE 136 pint_t nextCFI = p + cfiLength; 137 pint_t cieStart = p - ciePointer; 138 const char *err = parseCIE(addressSpace, cieStart, cieInfo); 139 if (err != NULL) 140 return err; 141 p += 4; 142 // parse pc begin and range 143 pint_t pcStart = 144 addressSpace.getEncodedP(p, nextCFI, cieInfo->pointerEncoding); 145 pint_t pcRange = 146 addressSpace.getEncodedP(p, nextCFI, cieInfo->pointerEncoding & 0x0F); 147 // parse rest of info 148 fdeInfo->lsda = 0; 149 // check for augmentation length 150 if (cieInfo->fdesHaveAugmentationData) { 151 pint_t augLen = (pint_t)addressSpace.getULEB128(p, nextCFI); 152 pint_t endOfAug = p + augLen; 153 if (cieInfo->lsdaEncoding != DW_EH_PE_omit) { 154 // peek at value (without indirection). Zero means no lsda 155 pint_t lsdaStart = p; 156 if (addressSpace.getEncodedP(p, nextCFI, cieInfo->lsdaEncoding & 0x0F) != 157 0) { 158 // reset pointer and re-parse lsda address 159 p = lsdaStart; 160 fdeInfo->lsda = 161 addressSpace.getEncodedP(p, nextCFI, cieInfo->lsdaEncoding); 162 } 163 } 164 p = endOfAug; 165 } 166 fdeInfo->fdeStart = fdeStart; 167 fdeInfo->fdeLength = nextCFI - fdeStart; 168 fdeInfo->fdeInstructions = p; 169 fdeInfo->pcStart = pcStart; 170 fdeInfo->pcEnd = pcStart + pcRange; 171 return NULL; // success 172 } 173 174 /// Scan an eh_frame section to find an FDE for a pc 175 template <typename A> 176 bool CFI_Parser<A>::findFDE(A &addressSpace, pint_t pc, pint_t ehSectionStart, 177 uint32_t sectionLength, pint_t fdeHint, 178 FDE_Info *fdeInfo, CIE_Info *cieInfo) { 179 //fprintf(stderr, "findFDE(0x%llX)\n", (long long)pc); 180 pint_t p = (fdeHint != 0) ? fdeHint : ehSectionStart; 181 const pint_t ehSectionEnd = p + sectionLength; 182 while (p < ehSectionEnd) { 183 pint_t currentCFI = p; 184 //fprintf(stderr, "findFDE() CFI at 0x%llX\n", (long long)p); 185 pint_t cfiLength = addressSpace.get32(p); 186 p += 4; 187 if (cfiLength == 0xffffffff) { 188 // 0xffffffff means length is really next 8 bytes 189 cfiLength = (pint_t)addressSpace.get64(p); 190 p += 8; 191 } 192 if (cfiLength == 0) 193 return false; // end marker 194 uint32_t id = addressSpace.get32(p); 195 if (id == 0) { 196 // skip over CIEs 197 p += cfiLength; 198 } else { 199 // process FDE to see if it covers pc 200 pint_t nextCFI = p + cfiLength; 201 uint32_t ciePointer = addressSpace.get32(p); 202 pint_t cieStart = p - ciePointer; 203 // validate pointer to CIE is within section 204 if ((ehSectionStart <= cieStart) && (cieStart < ehSectionEnd)) { 205 if (parseCIE(addressSpace, cieStart, cieInfo) == NULL) { 206 p += 4; 207 // parse pc begin and range 208 pint_t pcStart = 209 addressSpace.getEncodedP(p, nextCFI, cieInfo->pointerEncoding); 210 pint_t pcRange = addressSpace.getEncodedP( 211 p, nextCFI, cieInfo->pointerEncoding & 0x0F); 212 // test if pc is within the function this FDE covers 213 if ((pcStart < pc) && (pc <= pcStart + pcRange)) { 214 // parse rest of info 215 fdeInfo->lsda = 0; 216 // check for augmentation length 217 if (cieInfo->fdesHaveAugmentationData) { 218 pint_t augLen = (pint_t)addressSpace.getULEB128(p, nextCFI); 219 pint_t endOfAug = p + augLen; 220 if (cieInfo->lsdaEncoding != DW_EH_PE_omit) { 221 // peek at value (without indirection). Zero means no lsda 222 pint_t lsdaStart = p; 223 if (addressSpace.getEncodedP( 224 p, nextCFI, cieInfo->lsdaEncoding & 0x0F) != 0) { 225 // reset pointer and re-parse lsda address 226 p = lsdaStart; 227 fdeInfo->lsda = addressSpace 228 .getEncodedP(p, nextCFI, cieInfo->lsdaEncoding); 229 } 230 } 231 p = endOfAug; 232 } 233 fdeInfo->fdeStart = currentCFI; 234 fdeInfo->fdeLength = nextCFI - currentCFI; 235 fdeInfo->fdeInstructions = p; 236 fdeInfo->pcStart = pcStart; 237 fdeInfo->pcEnd = pcStart + pcRange; 238 return true; 239 } else { 240 // pc is not in begin/range, skip this FDE 241 } 242 } else { 243 // malformed CIE, now augmentation describing pc range encoding 244 } 245 } else { 246 // malformed FDE. CIE is bad 247 } 248 p = nextCFI; 249 } 250 } 251 return false; 252 } 253 254 /// Extract info from a CIE 255 template <typename A> 256 const char *CFI_Parser<A>::parseCIE(A &addressSpace, pint_t cie, 257 CIE_Info *cieInfo) { 258 cieInfo->pointerEncoding = 0; 259 cieInfo->lsdaEncoding = DW_EH_PE_omit; 260 cieInfo->personalityEncoding = 0; 261 cieInfo->personalityOffsetInCIE = 0; 262 cieInfo->personality = 0; 263 cieInfo->codeAlignFactor = 0; 264 cieInfo->dataAlignFactor = 0; 265 cieInfo->isSignalFrame = false; 266 cieInfo->fdesHaveAugmentationData = false; 267 cieInfo->cieStart = cie; 268 pint_t p = cie; 269 pint_t cieLength = (pint_t)addressSpace.get32(p); 270 p += 4; 271 pint_t cieContentEnd = p + cieLength; 272 if (cieLength == 0xffffffff) { 273 // 0xffffffff means length is really next 8 bytes 274 cieLength = (pint_t)addressSpace.get64(p); 275 p += 8; 276 cieContentEnd = p + cieLength; 277 } 278 if (cieLength == 0) 279 return NULL; 280 // CIE ID is always 0 281 if (addressSpace.get32(p) != 0) 282 return "CIE ID is not zero"; 283 p += 4; 284 // Version is always 1 or 3 285 uint8_t version = addressSpace.get8(p); 286 if ((version != 1) && (version != 3)) 287 return "CIE version is not 1 or 3"; 288 ++p; 289 // save start of augmentation string and find end 290 pint_t strStart = p; 291 while (addressSpace.get8(p) != 0) 292 ++p; 293 ++p; 294 // parse code aligment factor 295 cieInfo->codeAlignFactor = (uint32_t)addressSpace.getULEB128(p, cieContentEnd); 296 // parse data alignment factor 297 cieInfo->dataAlignFactor = (int)addressSpace.getSLEB128(p, cieContentEnd); 298 // parse return address register 299 uint64_t raReg = addressSpace.getULEB128(p, cieContentEnd); 300 assert(raReg < 255 && "return address register too large"); 301 cieInfo->returnAddressRegister = (uint8_t)raReg; 302 // parse augmentation data based on augmentation string 303 const char *result = NULL; 304 if (addressSpace.get8(strStart) == 'z') { 305 // parse augmentation data length 306 addressSpace.getULEB128(p, cieContentEnd); 307 for (pint_t s = strStart; addressSpace.get8(s) != '\0'; ++s) { 308 switch (addressSpace.get8(s)) { 309 case 'z': 310 cieInfo->fdesHaveAugmentationData = true; 311 break; 312 case 'P': 313 cieInfo->personalityEncoding = addressSpace.get8(p); 314 ++p; 315 cieInfo->personalityOffsetInCIE = (uint8_t)(p - cie); 316 cieInfo->personality = addressSpace 317 .getEncodedP(p, cieContentEnd, cieInfo->personalityEncoding); 318 break; 319 case 'L': 320 cieInfo->lsdaEncoding = addressSpace.get8(p); 321 ++p; 322 break; 323 case 'R': 324 cieInfo->pointerEncoding = addressSpace.get8(p); 325 ++p; 326 break; 327 case 'S': 328 cieInfo->isSignalFrame = true; 329 break; 330 default: 331 // ignore unknown letters 332 break; 333 } 334 } 335 } 336 cieInfo->cieLength = cieContentEnd - cieInfo->cieStart; 337 cieInfo->cieInstructions = p; 338 return result; 339 } 340 341 342 /// "run" the dwarf instructions and create the abstact PrologInfo for an FDE 343 template <typename A> 344 bool CFI_Parser<A>::parseFDEInstructions(A &addressSpace, 345 const FDE_Info &fdeInfo, 346 const CIE_Info &cieInfo, pint_t upToPC, 347 PrologInfo *results) { 348 // clear results 349 bzero(results, sizeof(PrologInfo)); 350 PrologInfoStackEntry *rememberStack = NULL; 351 352 // parse CIE then FDE instructions 353 return parseInstructions(addressSpace, cieInfo.cieInstructions, 354 cieInfo.cieStart + cieInfo.cieLength, cieInfo, 355 (pint_t)(-1), rememberStack, results) && 356 parseInstructions(addressSpace, fdeInfo.fdeInstructions, 357 fdeInfo.fdeStart + fdeInfo.fdeLength, cieInfo, 358 upToPC - fdeInfo.pcStart, rememberStack, results); 359 } 360 361 /// "run" the dwarf instructions 362 template <typename A> 363 bool CFI_Parser<A>::parseInstructions(A &addressSpace, pint_t instructions, 364 pint_t instructionsEnd, 365 const CIE_Info &cieInfo, pint_t pcoffset, 366 PrologInfoStackEntry *&rememberStack, 367 PrologInfo *results) { 368 const bool logDwarf = false; 369 pint_t p = instructions; 370 pint_t codeOffset = 0; 371 PrologInfo initialState = *results; 372 if (logDwarf) 373 fprintf(stderr, "parseInstructions(instructions=0x%0llX)\n", 374 (uint64_t) instructionsEnd); 375 376 // see Dwarf Spec, section 6.4.2 for details on unwind opcodes 377 while ((p < instructionsEnd) && (codeOffset < pcoffset)) { 378 uint64_t reg; 379 uint64_t reg2; 380 int64_t offset; 381 uint64_t length; 382 uint8_t opcode = addressSpace.get8(p); 383 uint8_t operand; 384 PrologInfoStackEntry *entry; 385 ++p; 386 switch (opcode) { 387 case DW_CFA_nop: 388 if (logDwarf) 389 fprintf(stderr, "DW_CFA_nop\n"); 390 break; 391 case DW_CFA_set_loc: 392 codeOffset = 393 addressSpace.getEncodedP(p, instructionsEnd, cieInfo.pointerEncoding); 394 if (logDwarf) 395 fprintf(stderr, "DW_CFA_set_loc\n"); 396 break; 397 case DW_CFA_advance_loc1: 398 codeOffset += (addressSpace.get8(p) * cieInfo.codeAlignFactor); 399 p += 1; 400 if (logDwarf) 401 fprintf(stderr, "DW_CFA_advance_loc1: new offset=%llu\n", 402 (uint64_t)codeOffset); 403 break; 404 case DW_CFA_advance_loc2: 405 codeOffset += (addressSpace.get16(p) * cieInfo.codeAlignFactor); 406 p += 2; 407 if (logDwarf) 408 fprintf(stderr, "DW_CFA_advance_loc2: new offset=%llu\n", 409 (uint64_t)codeOffset); 410 break; 411 case DW_CFA_advance_loc4: 412 codeOffset += (addressSpace.get32(p) * cieInfo.codeAlignFactor); 413 p += 4; 414 if (logDwarf) 415 fprintf(stderr, "DW_CFA_advance_loc4: new offset=%llu\n", 416 (uint64_t)codeOffset); 417 break; 418 case DW_CFA_offset_extended: 419 reg = addressSpace.getULEB128(p, instructionsEnd); 420 offset = (int64_t)addressSpace.getULEB128(p, instructionsEnd) 421 * cieInfo.dataAlignFactor; 422 if (reg > kMaxRegisterNumber) { 423 fprintf(stderr, 424 "malformed DW_CFA_offset_extended dwarf unwind, reg too big\n"); 425 return false; 426 } 427 results->savedRegisters[reg].location = kRegisterInCFA; 428 results->savedRegisters[reg].value = offset; 429 if (logDwarf) 430 fprintf(stderr, "DW_CFA_offset_extended(reg=%lld, offset=%lld)\n", reg, 431 offset); 432 break; 433 case DW_CFA_restore_extended: 434 reg = addressSpace.getULEB128(p, instructionsEnd); 435 ; 436 if (reg > kMaxRegisterNumber) { 437 fprintf( 438 stderr, 439 "malformed DW_CFA_restore_extended dwarf unwind, reg too big\n"); 440 return false; 441 } 442 results->savedRegisters[reg] = initialState.savedRegisters[reg]; 443 if (logDwarf) 444 fprintf(stderr, "DW_CFA_restore_extended(reg=%lld)\n", reg); 445 break; 446 case DW_CFA_undefined: 447 reg = addressSpace.getULEB128(p, instructionsEnd); 448 if (reg > kMaxRegisterNumber) { 449 fprintf(stderr, 450 "malformed DW_CFA_undefined dwarf unwind, reg too big\n"); 451 return false; 452 } 453 results->savedRegisters[reg].location = kRegisterUnused; 454 if (logDwarf) 455 fprintf(stderr, "DW_CFA_undefined(reg=%lld)\n", reg); 456 break; 457 case DW_CFA_same_value: 458 reg = addressSpace.getULEB128(p, instructionsEnd); 459 if (reg > kMaxRegisterNumber) { 460 fprintf(stderr, 461 "malformed DW_CFA_same_value dwarf unwind, reg too big\n"); 462 return false; 463 } 464 // <rdar://problem/8456377> DW_CFA_same_value unsupported 465 // "same value" means register was stored in frame, but its current 466 // value has not changed, so no need to restore from frame. 467 // We model this as if the register was never saved. 468 results->savedRegisters[reg].location = kRegisterUnused; 469 // set flag to disable conversion to compact unwind 470 results->sameValueUsed = true; 471 if (logDwarf) 472 fprintf(stderr, "DW_CFA_same_value(reg=%lld)\n", reg); 473 break; 474 case DW_CFA_register: 475 reg = addressSpace.getULEB128(p, instructionsEnd); 476 reg2 = addressSpace.getULEB128(p, instructionsEnd); 477 if (reg > kMaxRegisterNumber) { 478 fprintf(stderr, 479 "malformed DW_CFA_register dwarf unwind, reg too big\n"); 480 return false; 481 } 482 if (reg2 > kMaxRegisterNumber) { 483 fprintf(stderr, 484 "malformed DW_CFA_register dwarf unwind, reg2 too big\n"); 485 return false; 486 } 487 results->savedRegisters[reg].location = kRegisterInRegister; 488 results->savedRegisters[reg].value = (int64_t)reg2; 489 // set flag to disable conversion to compact unwind 490 results->registersInOtherRegisters = true; 491 if (logDwarf) 492 fprintf(stderr, "DW_CFA_register(reg=%lld, reg2=%lld)\n", reg, reg2); 493 break; 494 case DW_CFA_remember_state: 495 // avoid operator new, because that would be an upward dependency 496 entry = (PrologInfoStackEntry *)malloc(sizeof(PrologInfoStackEntry)); 497 if (entry != NULL) { 498 entry->next = rememberStack; 499 entry->info = *results; 500 rememberStack = entry; 501 } else { 502 return false; 503 } 504 if (logDwarf) 505 fprintf(stderr, "DW_CFA_remember_state\n"); 506 break; 507 case DW_CFA_restore_state: 508 if (rememberStack != NULL) { 509 PrologInfoStackEntry *top = rememberStack; 510 *results = top->info; 511 rememberStack = top->next; 512 free((char *)top); 513 } else { 514 return false; 515 } 516 if (logDwarf) 517 fprintf(stderr, "DW_CFA_restore_state\n"); 518 break; 519 case DW_CFA_def_cfa: 520 reg = addressSpace.getULEB128(p, instructionsEnd); 521 offset = (int64_t)addressSpace.getULEB128(p, instructionsEnd); 522 if (reg > kMaxRegisterNumber) { 523 fprintf(stderr, "malformed DW_CFA_def_cfa dwarf unwind, reg too big\n"); 524 return false; 525 } 526 results->cfaRegister = (uint32_t)reg; 527 results->cfaRegisterOffset = (int32_t)offset; 528 if (logDwarf) 529 fprintf(stderr, "DW_CFA_def_cfa(reg=%lld, offset=%lld)\n", reg, offset); 530 break; 531 case DW_CFA_def_cfa_register: 532 reg = addressSpace.getULEB128(p, instructionsEnd); 533 if (reg > kMaxRegisterNumber) { 534 fprintf( 535 stderr, 536 "malformed DW_CFA_def_cfa_register dwarf unwind, reg too big\n"); 537 return false; 538 } 539 results->cfaRegister = (uint32_t)reg; 540 if (logDwarf) 541 fprintf(stderr, "DW_CFA_def_cfa_register(%lld)\n", reg); 542 break; 543 case DW_CFA_def_cfa_offset: 544 results->cfaRegisterOffset = (int32_t) 545 addressSpace.getULEB128(p, instructionsEnd); 546 results->codeOffsetAtStackDecrement = (uint32_t)codeOffset; 547 if (logDwarf) 548 fprintf(stderr, "DW_CFA_def_cfa_offset(%d)\n", 549 results->cfaRegisterOffset); 550 break; 551 case DW_CFA_def_cfa_expression: 552 results->cfaRegister = 0; 553 results->cfaExpression = (int64_t)p; 554 length = addressSpace.getULEB128(p, instructionsEnd); 555 p += length; 556 if (logDwarf) 557 fprintf(stderr, 558 "DW_CFA_def_cfa_expression(expression=0x%llX, length=%llu)\n", 559 results->cfaExpression, length); 560 break; 561 case DW_CFA_expression: 562 reg = addressSpace.getULEB128(p, instructionsEnd); 563 if (reg > kMaxRegisterNumber) { 564 fprintf(stderr, 565 "malformed DW_CFA_expression dwarf unwind, reg too big\n"); 566 return false; 567 } 568 results->savedRegisters[reg].location = kRegisterAtExpression; 569 results->savedRegisters[reg].value = (int64_t)p; 570 length = addressSpace.getULEB128(p, instructionsEnd); 571 p += length; 572 if (logDwarf) 573 fprintf(stderr, 574 "DW_CFA_expression(reg=%lld, expression=0x%llX, length=%llu)\n", 575 reg, results->savedRegisters[reg].value, length); 576 break; 577 case DW_CFA_offset_extended_sf: 578 reg = addressSpace.getULEB128(p, instructionsEnd); 579 if (reg > kMaxRegisterNumber) { 580 fprintf( 581 stderr, 582 "malformed DW_CFA_offset_extended_sf dwarf unwind, reg too big\n"); 583 return false; 584 } 585 offset = 586 addressSpace.getSLEB128(p, instructionsEnd) * cieInfo.dataAlignFactor; 587 results->savedRegisters[reg].location = kRegisterInCFA; 588 results->savedRegisters[reg].value = offset; 589 if (logDwarf) 590 fprintf(stderr, "DW_CFA_offset_extended_sf(reg=%lld, offset=%lld)\n", 591 reg, offset); 592 break; 593 case DW_CFA_def_cfa_sf: 594 reg = addressSpace.getULEB128(p, instructionsEnd); 595 offset = 596 addressSpace.getSLEB128(p, instructionsEnd) * cieInfo.dataAlignFactor; 597 if (reg > kMaxRegisterNumber) { 598 fprintf(stderr, 599 "malformed DW_CFA_def_cfa_sf dwarf unwind, reg too big\n"); 600 return false; 601 } 602 results->cfaRegister = (uint32_t)reg; 603 results->cfaRegisterOffset = (int32_t)offset; 604 if (logDwarf) 605 fprintf(stderr, "DW_CFA_def_cfa_sf(reg=%lld, offset=%lld)\n", reg, 606 offset); 607 break; 608 case DW_CFA_def_cfa_offset_sf: 609 results->cfaRegisterOffset = (int32_t) 610 (addressSpace.getSLEB128(p, instructionsEnd) * cieInfo.dataAlignFactor); 611 results->codeOffsetAtStackDecrement = (uint32_t)codeOffset; 612 if (logDwarf) 613 fprintf(stderr, "DW_CFA_def_cfa_offset_sf(%d)\n", 614 results->cfaRegisterOffset); 615 break; 616 case DW_CFA_val_offset: 617 reg = addressSpace.getULEB128(p, instructionsEnd); 618 offset = (int64_t)addressSpace.getULEB128(p, instructionsEnd) 619 * cieInfo.dataAlignFactor; 620 results->savedRegisters[reg].location = kRegisterOffsetFromCFA; 621 results->savedRegisters[reg].value = offset; 622 if (logDwarf) 623 fprintf(stderr, "DW_CFA_val_offset(reg=%lld, offset=%lld\n", reg, 624 offset); 625 break; 626 case DW_CFA_val_offset_sf: 627 reg = addressSpace.getULEB128(p, instructionsEnd); 628 if (reg > kMaxRegisterNumber) { 629 fprintf(stderr, 630 "malformed DW_CFA_val_offset_sf dwarf unwind, reg too big\n"); 631 return false; 632 } 633 offset = 634 addressSpace.getSLEB128(p, instructionsEnd) * cieInfo.dataAlignFactor; 635 results->savedRegisters[reg].location = kRegisterOffsetFromCFA; 636 results->savedRegisters[reg].value = offset; 637 if (logDwarf) 638 fprintf(stderr, "DW_CFA_val_offset_sf(reg=%lld, offset=%lld\n", reg, 639 offset); 640 break; 641 case DW_CFA_val_expression: 642 reg = addressSpace.getULEB128(p, instructionsEnd); 643 if (reg > kMaxRegisterNumber) { 644 fprintf(stderr, 645 "malformed DW_CFA_val_expression dwarf unwind, reg too big\n"); 646 return false; 647 } 648 results->savedRegisters[reg].location = kRegisterIsExpression; 649 results->savedRegisters[reg].value = (int64_t)p; 650 length = addressSpace.getULEB128(p, instructionsEnd); 651 p += length; 652 if (logDwarf) 653 fprintf( 654 stderr, 655 "DW_CFA_val_expression(reg=%lld, expression=0x%llX, length=%lld)\n", 656 reg, results->savedRegisters[reg].value, length); 657 break; 658 case DW_CFA_GNU_args_size: 659 length = addressSpace.getULEB128(p, instructionsEnd); 660 results->spExtraArgSize = (uint32_t)length; 661 if (logDwarf) 662 fprintf(stderr, "DW_CFA_GNU_args_size(%lld)\n", length); 663 break; 664 case DW_CFA_GNU_negative_offset_extended: 665 reg = addressSpace.getULEB128(p, instructionsEnd); 666 if (reg > kMaxRegisterNumber) { 667 fprintf(stderr, "malformed DW_CFA_GNU_negative_offset_extended dwarf " 668 "unwind, reg too big\n"); 669 return false; 670 } 671 offset = (int64_t)addressSpace.getULEB128(p, instructionsEnd) 672 * cieInfo.dataAlignFactor; 673 results->savedRegisters[reg].location = kRegisterInCFA; 674 results->savedRegisters[reg].value = -offset; 675 if (logDwarf) 676 fprintf(stderr, "DW_CFA_GNU_negative_offset_extended(%lld)\n", offset); 677 break; 678 default: 679 operand = opcode & 0x3F; 680 switch (opcode & 0xC0) { 681 case DW_CFA_offset: 682 reg = operand; 683 offset = (int64_t)addressSpace.getULEB128(p, instructionsEnd) 684 * cieInfo.dataAlignFactor; 685 results->savedRegisters[reg].location = kRegisterInCFA; 686 results->savedRegisters[reg].value = offset; 687 if (logDwarf) 688 fprintf(stderr, "DW_CFA_offset(reg=%d, offset=%lld)\n", operand, 689 offset); 690 break; 691 case DW_CFA_advance_loc: 692 codeOffset += operand * cieInfo.codeAlignFactor; 693 if (logDwarf) 694 fprintf(stderr, "DW_CFA_advance_loc: new offset=%llu\n", 695 (uint64_t)codeOffset); 696 break; 697 case DW_CFA_restore: 698 reg = operand; 699 results->savedRegisters[reg] = initialState.savedRegisters[reg]; 700 if (logDwarf) 701 fprintf(stderr, "DW_CFA_restore(reg=%lld)\n", reg); 702 break; 703 default: 704 if (logDwarf) 705 fprintf(stderr, "unknown CFA opcode 0x%02X\n", opcode); 706 return false; 707 } 708 } 709 } 710 711 return true; 712 } 713 714 } // namespace libunwind 715 716 #endif // __DWARF_PARSER_HPP__ 717
