1 //===- DWARFDebugFrame.h - Parsing of .debug_frame ------------------------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 10 #include "llvm/DebugInfo/DWARF/DWARFDebugFrame.h" 11 #include "llvm/ADT/DenseMap.h" 12 #include "llvm/ADT/Optional.h" 13 #include "llvm/ADT/StringExtras.h" 14 #include "llvm/ADT/StringRef.h" 15 #include "llvm/BinaryFormat/Dwarf.h" 16 #include "llvm/Support/Casting.h" 17 #include "llvm/Support/Compiler.h" 18 #include "llvm/Support/DataExtractor.h" 19 #include "llvm/Support/Errc.h" 20 #include "llvm/Support/ErrorHandling.h" 21 #include "llvm/Support/Format.h" 22 #include "llvm/Support/raw_ostream.h" 23 #include <algorithm> 24 #include <cassert> 25 #include <cinttypes> 26 #include <cstdint> 27 #include <string> 28 #include <vector> 29 30 using namespace llvm; 31 using namespace dwarf; 32 33 34 // See DWARF standard v3, section 7.23 35 const uint8_t DWARF_CFI_PRIMARY_OPCODE_MASK = 0xc0; 36 const uint8_t DWARF_CFI_PRIMARY_OPERAND_MASK = 0x3f; 37 38 Error CFIProgram::parse(DataExtractor Data, uint32_t *Offset, 39 uint32_t EndOffset) { 40 while (*Offset < EndOffset) { 41 uint8_t Opcode = Data.getU8(Offset); 42 // Some instructions have a primary opcode encoded in the top bits. 43 uint8_t Primary = Opcode & DWARF_CFI_PRIMARY_OPCODE_MASK; 44 45 if (Primary) { 46 // If it's a primary opcode, the first operand is encoded in the bottom 47 // bits of the opcode itself. 48 uint64_t Op1 = Opcode & DWARF_CFI_PRIMARY_OPERAND_MASK; 49 switch (Primary) { 50 default: 51 return createStringError(errc::illegal_byte_sequence, 52 "Invalid primary CFI opcode 0x%" PRIx8, 53 Primary); 54 case DW_CFA_advance_loc: 55 case DW_CFA_restore: 56 addInstruction(Primary, Op1); 57 break; 58 case DW_CFA_offset: 59 addInstruction(Primary, Op1, Data.getULEB128(Offset)); 60 break; 61 } 62 } else { 63 // Extended opcode - its value is Opcode itself. 64 switch (Opcode) { 65 default: 66 return createStringError(errc::illegal_byte_sequence, 67 "Invalid extended CFI opcode 0x%" PRIx8, 68 Opcode); 69 case DW_CFA_nop: 70 case DW_CFA_remember_state: 71 case DW_CFA_restore_state: 72 case DW_CFA_GNU_window_save: 73 // No operands 74 addInstruction(Opcode); 75 break; 76 case DW_CFA_set_loc: 77 // Operands: Address 78 addInstruction(Opcode, Data.getAddress(Offset)); 79 break; 80 case DW_CFA_advance_loc1: 81 // Operands: 1-byte delta 82 addInstruction(Opcode, Data.getU8(Offset)); 83 break; 84 case DW_CFA_advance_loc2: 85 // Operands: 2-byte delta 86 addInstruction(Opcode, Data.getU16(Offset)); 87 break; 88 case DW_CFA_advance_loc4: 89 // Operands: 4-byte delta 90 addInstruction(Opcode, Data.getU32(Offset)); 91 break; 92 case DW_CFA_restore_extended: 93 case DW_CFA_undefined: 94 case DW_CFA_same_value: 95 case DW_CFA_def_cfa_register: 96 case DW_CFA_def_cfa_offset: 97 case DW_CFA_GNU_args_size: 98 // Operands: ULEB128 99 addInstruction(Opcode, Data.getULEB128(Offset)); 100 break; 101 case DW_CFA_def_cfa_offset_sf: 102 // Operands: SLEB128 103 addInstruction(Opcode, Data.getSLEB128(Offset)); 104 break; 105 case DW_CFA_offset_extended: 106 case DW_CFA_register: 107 case DW_CFA_def_cfa: 108 case DW_CFA_val_offset: { 109 // Operands: ULEB128, ULEB128 110 // Note: We can not embed getULEB128 directly into function 111 // argument list. getULEB128 changes Offset and order of evaluation 112 // for arguments is unspecified. 113 auto op1 = Data.getULEB128(Offset); 114 auto op2 = Data.getULEB128(Offset); 115 addInstruction(Opcode, op1, op2); 116 break; 117 } 118 case DW_CFA_offset_extended_sf: 119 case DW_CFA_def_cfa_sf: 120 case DW_CFA_val_offset_sf: { 121 // Operands: ULEB128, SLEB128 122 // Note: see comment for the previous case 123 auto op1 = Data.getULEB128(Offset); 124 auto op2 = (uint64_t)Data.getSLEB128(Offset); 125 addInstruction(Opcode, op1, op2); 126 break; 127 } 128 case DW_CFA_def_cfa_expression: { 129 uint32_t ExprLength = Data.getULEB128(Offset); 130 addInstruction(Opcode, 0); 131 DataExtractor Extractor( 132 Data.getData().slice(*Offset, *Offset + ExprLength), 133 Data.isLittleEndian(), Data.getAddressSize()); 134 Instructions.back().Expression = DWARFExpression( 135 Extractor, Data.getAddressSize(), dwarf::DWARF_VERSION); 136 *Offset += ExprLength; 137 break; 138 } 139 case DW_CFA_expression: 140 case DW_CFA_val_expression: { 141 auto RegNum = Data.getULEB128(Offset); 142 auto BlockLength = Data.getULEB128(Offset); 143 addInstruction(Opcode, RegNum, 0); 144 DataExtractor Extractor( 145 Data.getData().slice(*Offset, *Offset + BlockLength), 146 Data.isLittleEndian(), Data.getAddressSize()); 147 Instructions.back().Expression = DWARFExpression( 148 Extractor, Data.getAddressSize(), dwarf::DWARF_VERSION); 149 *Offset += BlockLength; 150 break; 151 } 152 } 153 } 154 } 155 156 return Error::success(); 157 } 158 159 namespace { 160 161 162 } // end anonymous namespace 163 164 ArrayRef<CFIProgram::OperandType[2]> CFIProgram::getOperandTypes() { 165 static OperandType OpTypes[DW_CFA_restore+1][2]; 166 static bool Initialized = false; 167 if (Initialized) { 168 return ArrayRef<OperandType[2]>(&OpTypes[0], DW_CFA_restore+1); 169 } 170 Initialized = true; 171 172 #define DECLARE_OP2(OP, OPTYPE0, OPTYPE1) \ 173 do { \ 174 OpTypes[OP][0] = OPTYPE0; \ 175 OpTypes[OP][1] = OPTYPE1; \ 176 } while (false) 177 #define DECLARE_OP1(OP, OPTYPE0) DECLARE_OP2(OP, OPTYPE0, OT_None) 178 #define DECLARE_OP0(OP) DECLARE_OP1(OP, OT_None) 179 180 DECLARE_OP1(DW_CFA_set_loc, OT_Address); 181 DECLARE_OP1(DW_CFA_advance_loc, OT_FactoredCodeOffset); 182 DECLARE_OP1(DW_CFA_advance_loc1, OT_FactoredCodeOffset); 183 DECLARE_OP1(DW_CFA_advance_loc2, OT_FactoredCodeOffset); 184 DECLARE_OP1(DW_CFA_advance_loc4, OT_FactoredCodeOffset); 185 DECLARE_OP1(DW_CFA_MIPS_advance_loc8, OT_FactoredCodeOffset); 186 DECLARE_OP2(DW_CFA_def_cfa, OT_Register, OT_Offset); 187 DECLARE_OP2(DW_CFA_def_cfa_sf, OT_Register, OT_SignedFactDataOffset); 188 DECLARE_OP1(DW_CFA_def_cfa_register, OT_Register); 189 DECLARE_OP1(DW_CFA_def_cfa_offset, OT_Offset); 190 DECLARE_OP1(DW_CFA_def_cfa_offset_sf, OT_SignedFactDataOffset); 191 DECLARE_OP1(DW_CFA_def_cfa_expression, OT_Expression); 192 DECLARE_OP1(DW_CFA_undefined, OT_Register); 193 DECLARE_OP1(DW_CFA_same_value, OT_Register); 194 DECLARE_OP2(DW_CFA_offset, OT_Register, OT_UnsignedFactDataOffset); 195 DECLARE_OP2(DW_CFA_offset_extended, OT_Register, OT_UnsignedFactDataOffset); 196 DECLARE_OP2(DW_CFA_offset_extended_sf, OT_Register, OT_SignedFactDataOffset); 197 DECLARE_OP2(DW_CFA_val_offset, OT_Register, OT_UnsignedFactDataOffset); 198 DECLARE_OP2(DW_CFA_val_offset_sf, OT_Register, OT_SignedFactDataOffset); 199 DECLARE_OP2(DW_CFA_register, OT_Register, OT_Register); 200 DECLARE_OP2(DW_CFA_expression, OT_Register, OT_Expression); 201 DECLARE_OP2(DW_CFA_val_expression, OT_Register, OT_Expression); 202 DECLARE_OP1(DW_CFA_restore, OT_Register); 203 DECLARE_OP1(DW_CFA_restore_extended, OT_Register); 204 DECLARE_OP0(DW_CFA_remember_state); 205 DECLARE_OP0(DW_CFA_restore_state); 206 DECLARE_OP0(DW_CFA_GNU_window_save); 207 DECLARE_OP1(DW_CFA_GNU_args_size, OT_Offset); 208 DECLARE_OP0(DW_CFA_nop); 209 210 #undef DECLARE_OP0 211 #undef DECLARE_OP1 212 #undef DECLARE_OP2 213 214 return ArrayRef<OperandType[2]>(&OpTypes[0], DW_CFA_restore+1); 215 } 216 217 /// Print \p Opcode's operand number \p OperandIdx which has value \p Operand. 218 void CFIProgram::printOperand(raw_ostream &OS, const MCRegisterInfo *MRI, 219 bool IsEH, const Instruction &Instr, 220 unsigned OperandIdx, uint64_t Operand) const { 221 assert(OperandIdx < 2); 222 uint8_t Opcode = Instr.Opcode; 223 OperandType Type = getOperandTypes()[Opcode][OperandIdx]; 224 225 switch (Type) { 226 case OT_Unset: { 227 OS << " Unsupported " << (OperandIdx ? "second" : "first") << " operand to"; 228 auto OpcodeName = CallFrameString(Opcode); 229 if (!OpcodeName.empty()) 230 OS << " " << OpcodeName; 231 else 232 OS << format(" Opcode %x", Opcode); 233 break; 234 } 235 case OT_None: 236 break; 237 case OT_Address: 238 OS << format(" %" PRIx64, Operand); 239 break; 240 case OT_Offset: 241 // The offsets are all encoded in a unsigned form, but in practice 242 // consumers use them signed. It's most certainly legacy due to 243 // the lack of signed variants in the first Dwarf standards. 244 OS << format(" %+" PRId64, int64_t(Operand)); 245 break; 246 case OT_FactoredCodeOffset: // Always Unsigned 247 if (CodeAlignmentFactor) 248 OS << format(" %" PRId64, Operand * CodeAlignmentFactor); 249 else 250 OS << format(" %" PRId64 "*code_alignment_factor" , Operand); 251 break; 252 case OT_SignedFactDataOffset: 253 if (DataAlignmentFactor) 254 OS << format(" %" PRId64, int64_t(Operand) * DataAlignmentFactor); 255 else 256 OS << format(" %" PRId64 "*data_alignment_factor" , int64_t(Operand)); 257 break; 258 case OT_UnsignedFactDataOffset: 259 if (DataAlignmentFactor) 260 OS << format(" %" PRId64, Operand * DataAlignmentFactor); 261 else 262 OS << format(" %" PRId64 "*data_alignment_factor" , Operand); 263 break; 264 case OT_Register: 265 OS << format(" reg%" PRId64, Operand); 266 break; 267 case OT_Expression: 268 assert(Instr.Expression && "missing DWARFExpression object"); 269 OS << " "; 270 Instr.Expression->print(OS, MRI, IsEH); 271 break; 272 } 273 } 274 275 void CFIProgram::dump(raw_ostream &OS, const MCRegisterInfo *MRI, bool IsEH, 276 unsigned IndentLevel) const { 277 for (const auto &Instr : Instructions) { 278 uint8_t Opcode = Instr.Opcode; 279 if (Opcode & DWARF_CFI_PRIMARY_OPCODE_MASK) 280 Opcode &= DWARF_CFI_PRIMARY_OPCODE_MASK; 281 OS.indent(2 * IndentLevel); 282 OS << CallFrameString(Opcode) << ":"; 283 for (unsigned i = 0; i < Instr.Ops.size(); ++i) 284 printOperand(OS, MRI, IsEH, Instr, i, Instr.Ops[i]); 285 OS << '\n'; 286 } 287 } 288 289 void CIE::dump(raw_ostream &OS, const MCRegisterInfo *MRI, bool IsEH) const { 290 OS << format("%08x %08x %08x CIE", (uint32_t)Offset, (uint32_t)Length, 291 DW_CIE_ID) 292 << "\n"; 293 OS << format(" Version: %d\n", Version); 294 OS << " Augmentation: \"" << Augmentation << "\"\n"; 295 if (Version >= 4) { 296 OS << format(" Address size: %u\n", (uint32_t)AddressSize); 297 OS << format(" Segment desc size: %u\n", 298 (uint32_t)SegmentDescriptorSize); 299 } 300 OS << format(" Code alignment factor: %u\n", (uint32_t)CodeAlignmentFactor); 301 OS << format(" Data alignment factor: %d\n", (int32_t)DataAlignmentFactor); 302 OS << format(" Return address column: %d\n", (int32_t)ReturnAddressRegister); 303 if (Personality) 304 OS << format(" Personality Address: %08x\n", *Personality); 305 if (!AugmentationData.empty()) { 306 OS << " Augmentation data: "; 307 for (uint8_t Byte : AugmentationData) 308 OS << ' ' << hexdigit(Byte >> 4) << hexdigit(Byte & 0xf); 309 OS << "\n"; 310 } 311 OS << "\n"; 312 CFIs.dump(OS, MRI, IsEH); 313 OS << "\n"; 314 } 315 316 void FDE::dump(raw_ostream &OS, const MCRegisterInfo *MRI, bool IsEH) const { 317 OS << format("%08x %08x %08x FDE ", (uint32_t)Offset, (uint32_t)Length, 318 (int32_t)LinkedCIEOffset); 319 OS << format("cie=%08x pc=%08x...%08x\n", (int32_t)LinkedCIEOffset, 320 (uint32_t)InitialLocation, 321 (uint32_t)InitialLocation + (uint32_t)AddressRange); 322 if (LSDAAddress) 323 OS << format(" LSDA Address: %08x\n", *LSDAAddress); 324 CFIs.dump(OS, MRI, IsEH); 325 OS << "\n"; 326 } 327 328 DWARFDebugFrame::DWARFDebugFrame(bool IsEH, uint64_t EHFrameAddress) 329 : IsEH(IsEH), EHFrameAddress(EHFrameAddress) {} 330 331 DWARFDebugFrame::~DWARFDebugFrame() = default; 332 333 static void LLVM_ATTRIBUTE_UNUSED dumpDataAux(DataExtractor Data, 334 uint32_t Offset, int Length) { 335 errs() << "DUMP: "; 336 for (int i = 0; i < Length; ++i) { 337 uint8_t c = Data.getU8(&Offset); 338 errs().write_hex(c); errs() << " "; 339 } 340 errs() << "\n"; 341 } 342 343 // This is a workaround for old compilers which do not allow 344 // noreturn attribute usage in lambdas. Once the support for those 345 // compilers are phased out, we can remove this and return back to 346 // a ReportError lambda: [StartOffset](const char *ErrorMsg). 347 static void LLVM_ATTRIBUTE_NORETURN ReportError(uint32_t StartOffset, 348 const char *ErrorMsg) { 349 std::string Str; 350 raw_string_ostream OS(Str); 351 OS << format(ErrorMsg, StartOffset); 352 OS.flush(); 353 report_fatal_error(Str); 354 } 355 356 void DWARFDebugFrame::parse(DWARFDataExtractor Data) { 357 uint32_t Offset = 0; 358 DenseMap<uint32_t, CIE *> CIEs; 359 360 while (Data.isValidOffset(Offset)) { 361 uint32_t StartOffset = Offset; 362 363 bool IsDWARF64 = false; 364 uint64_t Length = Data.getU32(&Offset); 365 uint64_t Id; 366 367 if (Length == UINT32_MAX) { 368 // DWARF-64 is distinguished by the first 32 bits of the initial length 369 // field being 0xffffffff. Then, the next 64 bits are the actual entry 370 // length. 371 IsDWARF64 = true; 372 Length = Data.getU64(&Offset); 373 } 374 375 // At this point, Offset points to the next field after Length. 376 // Length is the structure size excluding itself. Compute an offset one 377 // past the end of the structure (needed to know how many instructions to 378 // read). 379 // TODO: For honest DWARF64 support, DataExtractor will have to treat 380 // offset_ptr as uint64_t* 381 uint32_t StartStructureOffset = Offset; 382 uint32_t EndStructureOffset = Offset + static_cast<uint32_t>(Length); 383 384 // The Id field's size depends on the DWARF format 385 Id = Data.getUnsigned(&Offset, (IsDWARF64 && !IsEH) ? 8 : 4); 386 bool IsCIE = 387 ((IsDWARF64 && Id == DW64_CIE_ID) || Id == DW_CIE_ID || (IsEH && !Id)); 388 389 if (IsCIE) { 390 uint8_t Version = Data.getU8(&Offset); 391 const char *Augmentation = Data.getCStr(&Offset); 392 StringRef AugmentationString(Augmentation ? Augmentation : ""); 393 uint8_t AddressSize = Version < 4 ? Data.getAddressSize() : 394 Data.getU8(&Offset); 395 Data.setAddressSize(AddressSize); 396 uint8_t SegmentDescriptorSize = Version < 4 ? 0 : Data.getU8(&Offset); 397 uint64_t CodeAlignmentFactor = Data.getULEB128(&Offset); 398 int64_t DataAlignmentFactor = Data.getSLEB128(&Offset); 399 uint64_t ReturnAddressRegister = Data.getULEB128(&Offset); 400 401 // Parse the augmentation data for EH CIEs 402 StringRef AugmentationData(""); 403 uint32_t FDEPointerEncoding = DW_EH_PE_absptr; 404 uint32_t LSDAPointerEncoding = DW_EH_PE_omit; 405 Optional<uint64_t> Personality; 406 Optional<uint32_t> PersonalityEncoding; 407 if (IsEH) { 408 Optional<uint64_t> AugmentationLength; 409 uint32_t StartAugmentationOffset; 410 uint32_t EndAugmentationOffset; 411 412 // Walk the augmentation string to get all the augmentation data. 413 for (unsigned i = 0, e = AugmentationString.size(); i != e; ++i) { 414 switch (AugmentationString[i]) { 415 default: 416 ReportError(StartOffset, 417 "Unknown augmentation character in entry at %lx"); 418 case 'L': 419 LSDAPointerEncoding = Data.getU8(&Offset); 420 break; 421 case 'P': { 422 if (Personality) 423 ReportError(StartOffset, 424 "Duplicate personality in entry at %lx"); 425 PersonalityEncoding = Data.getU8(&Offset); 426 Personality = Data.getEncodedPointer( 427 &Offset, *PersonalityEncoding, 428 EHFrameAddress ? EHFrameAddress + Offset : 0); 429 break; 430 } 431 case 'R': 432 FDEPointerEncoding = Data.getU8(&Offset); 433 break; 434 case 'S': 435 // Current frame is a signal trampoline. 436 break; 437 case 'z': 438 if (i) 439 ReportError(StartOffset, 440 "'z' must be the first character at %lx"); 441 // Parse the augmentation length first. We only parse it if 442 // the string contains a 'z'. 443 AugmentationLength = Data.getULEB128(&Offset); 444 StartAugmentationOffset = Offset; 445 EndAugmentationOffset = Offset + 446 static_cast<uint32_t>(*AugmentationLength); 447 } 448 } 449 450 if (AugmentationLength.hasValue()) { 451 if (Offset != EndAugmentationOffset) 452 ReportError(StartOffset, "Parsing augmentation data at %lx failed"); 453 454 AugmentationData = Data.getData().slice(StartAugmentationOffset, 455 EndAugmentationOffset); 456 } 457 } 458 459 auto Cie = llvm::make_unique<CIE>( 460 StartOffset, Length, Version, AugmentationString, AddressSize, 461 SegmentDescriptorSize, CodeAlignmentFactor, DataAlignmentFactor, 462 ReturnAddressRegister, AugmentationData, FDEPointerEncoding, 463 LSDAPointerEncoding, Personality, PersonalityEncoding); 464 CIEs[StartOffset] = Cie.get(); 465 Entries.emplace_back(std::move(Cie)); 466 } else { 467 // FDE 468 uint64_t CIEPointer = Id; 469 uint64_t InitialLocation = 0; 470 uint64_t AddressRange = 0; 471 Optional<uint64_t> LSDAAddress; 472 CIE *Cie = CIEs[IsEH ? (StartStructureOffset - CIEPointer) : CIEPointer]; 473 474 if (IsEH) { 475 // The address size is encoded in the CIE we reference. 476 if (!Cie) 477 ReportError(StartOffset, 478 "Parsing FDE data at %lx failed due to missing CIE"); 479 480 if (auto Val = Data.getEncodedPointer( 481 &Offset, Cie->getFDEPointerEncoding(), 482 EHFrameAddress ? EHFrameAddress + Offset : 0)) { 483 InitialLocation = *Val; 484 } 485 if (auto Val = Data.getEncodedPointer( 486 &Offset, Cie->getFDEPointerEncoding(), 0)) { 487 AddressRange = *Val; 488 } 489 490 StringRef AugmentationString = Cie->getAugmentationString(); 491 if (!AugmentationString.empty()) { 492 // Parse the augmentation length and data for this FDE. 493 uint64_t AugmentationLength = Data.getULEB128(&Offset); 494 495 uint32_t EndAugmentationOffset = 496 Offset + static_cast<uint32_t>(AugmentationLength); 497 498 // Decode the LSDA if the CIE augmentation string said we should. 499 if (Cie->getLSDAPointerEncoding() != DW_EH_PE_omit) { 500 LSDAAddress = Data.getEncodedPointer( 501 &Offset, Cie->getLSDAPointerEncoding(), 502 EHFrameAddress ? Offset + EHFrameAddress : 0); 503 } 504 505 if (Offset != EndAugmentationOffset) 506 ReportError(StartOffset, "Parsing augmentation data at %lx failed"); 507 } 508 } else { 509 InitialLocation = Data.getAddress(&Offset); 510 AddressRange = Data.getAddress(&Offset); 511 } 512 513 Entries.emplace_back(new FDE(StartOffset, Length, CIEPointer, 514 InitialLocation, AddressRange, 515 Cie, LSDAAddress)); 516 } 517 518 if (Error E = 519 Entries.back()->cfis().parse(Data, &Offset, EndStructureOffset)) { 520 report_fatal_error(toString(std::move(E))); 521 } 522 523 if (Offset != EndStructureOffset) 524 ReportError(StartOffset, "Parsing entry instructions at %lx failed"); 525 } 526 } 527 528 FrameEntry *DWARFDebugFrame::getEntryAtOffset(uint64_t Offset) const { 529 auto It = 530 std::lower_bound(Entries.begin(), Entries.end(), Offset, 531 [](const std::unique_ptr<FrameEntry> &E, 532 uint64_t Offset) { return E->getOffset() < Offset; }); 533 if (It != Entries.end() && (*It)->getOffset() == Offset) 534 return It->get(); 535 return nullptr; 536 } 537 538 void DWARFDebugFrame::dump(raw_ostream &OS, const MCRegisterInfo *MRI, 539 Optional<uint64_t> Offset) const { 540 if (Offset) { 541 if (auto *Entry = getEntryAtOffset(*Offset)) 542 Entry->dump(OS, MRI, IsEH); 543 return; 544 } 545 546 OS << "\n"; 547 for (const auto &Entry : Entries) 548 Entry->dump(OS, MRI, IsEH); 549 } 550