1 //===- DWARFDebugFrame.h - Parsing of .debug_frame ------------------------===//
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
7 //===----------------------------------------------------------------------===//
9 #include "llvm/DebugInfo/DWARF/DWARFDebugFrame.h"
10 #include "llvm/ADT/DenseMap.h"
11 #include "llvm/ADT/Optional.h"
12 #include "llvm/ADT/StringExtras.h"
13 #include "llvm/ADT/StringRef.h"
14 #include "llvm/BinaryFormat/Dwarf.h"
15 #include "llvm/Support/Casting.h"
16 #include "llvm/Support/Compiler.h"
17 #include "llvm/Support/DataExtractor.h"
18 #include "llvm/Support/Errc.h"
19 #include "llvm/Support/ErrorHandling.h"
20 #include "llvm/Support/Format.h"
21 #include "llvm/Support/raw_ostream.h"
30 using namespace dwarf;
33 // See DWARF standard v3, section 7.23
34 const uint8_t DWARF_CFI_PRIMARY_OPCODE_MASK = 0xc0;
35 const uint8_t DWARF_CFI_PRIMARY_OPERAND_MASK = 0x3f;
37 Error CFIProgram::parse(DataExtractor Data, uint32_t *Offset,
39 while (*Offset < EndOffset) {
40 uint8_t Opcode = Data.getU8(Offset);
41 // Some instructions have a primary opcode encoded in the top bits.
42 uint8_t Primary = Opcode & DWARF_CFI_PRIMARY_OPCODE_MASK;
45 // If it's a primary opcode, the first operand is encoded in the bottom
46 // bits of the opcode itself.
47 uint64_t Op1 = Opcode & DWARF_CFI_PRIMARY_OPERAND_MASK;
50 return createStringError(errc::illegal_byte_sequence,
51 "Invalid primary CFI opcode 0x%" PRIx8,
53 case DW_CFA_advance_loc:
55 addInstruction(Primary, Op1);
58 addInstruction(Primary, Op1, Data.getULEB128(Offset));
62 // Extended opcode - its value is Opcode itself.
65 return createStringError(errc::illegal_byte_sequence,
66 "Invalid extended CFI opcode 0x%" PRIx8,
69 case DW_CFA_remember_state:
70 case DW_CFA_restore_state:
71 case DW_CFA_GNU_window_save:
73 addInstruction(Opcode);
77 addInstruction(Opcode, Data.getAddress(Offset));
79 case DW_CFA_advance_loc1:
80 // Operands: 1-byte delta
81 addInstruction(Opcode, Data.getU8(Offset));
83 case DW_CFA_advance_loc2:
84 // Operands: 2-byte delta
85 addInstruction(Opcode, Data.getU16(Offset));
87 case DW_CFA_advance_loc4:
88 // Operands: 4-byte delta
89 addInstruction(Opcode, Data.getU32(Offset));
91 case DW_CFA_restore_extended:
92 case DW_CFA_undefined:
93 case DW_CFA_same_value:
94 case DW_CFA_def_cfa_register:
95 case DW_CFA_def_cfa_offset:
96 case DW_CFA_GNU_args_size:
98 addInstruction(Opcode, Data.getULEB128(Offset));
100 case DW_CFA_def_cfa_offset_sf:
102 addInstruction(Opcode, Data.getSLEB128(Offset));
104 case DW_CFA_offset_extended:
105 case DW_CFA_register:
107 case DW_CFA_val_offset: {
108 // Operands: ULEB128, ULEB128
109 // Note: We can not embed getULEB128 directly into function
110 // argument list. getULEB128 changes Offset and order of evaluation
111 // for arguments is unspecified.
112 auto op1 = Data.getULEB128(Offset);
113 auto op2 = Data.getULEB128(Offset);
114 addInstruction(Opcode, op1, op2);
117 case DW_CFA_offset_extended_sf:
118 case DW_CFA_def_cfa_sf:
119 case DW_CFA_val_offset_sf: {
120 // Operands: ULEB128, SLEB128
121 // Note: see comment for the previous case
122 auto op1 = Data.getULEB128(Offset);
123 auto op2 = (uint64_t)Data.getSLEB128(Offset);
124 addInstruction(Opcode, op1, op2);
127 case DW_CFA_def_cfa_expression: {
128 uint32_t ExprLength = Data.getULEB128(Offset);
129 addInstruction(Opcode, 0);
130 DataExtractor Extractor(
131 Data.getData().slice(*Offset, *Offset + ExprLength),
132 Data.isLittleEndian(), Data.getAddressSize());
133 Instructions.back().Expression = DWARFExpression(
134 Extractor, Data.getAddressSize(), dwarf::DWARF_VERSION);
135 *Offset += ExprLength;
138 case DW_CFA_expression:
139 case DW_CFA_val_expression: {
140 auto RegNum = Data.getULEB128(Offset);
141 auto BlockLength = Data.getULEB128(Offset);
142 addInstruction(Opcode, RegNum, 0);
143 DataExtractor Extractor(
144 Data.getData().slice(*Offset, *Offset + BlockLength),
145 Data.isLittleEndian(), Data.getAddressSize());
146 Instructions.back().Expression = DWARFExpression(
147 Extractor, Data.getAddressSize(), dwarf::DWARF_VERSION);
148 *Offset += BlockLength;
155 return Error::success();
161 } // end anonymous namespace
163 ArrayRef<CFIProgram::OperandType[2]> CFIProgram::getOperandTypes() {
164 static OperandType OpTypes[DW_CFA_restore+1][2];
165 static bool Initialized = false;
167 return ArrayRef<OperandType[2]>(&OpTypes[0], DW_CFA_restore+1);
171 #define DECLARE_OP2(OP, OPTYPE0, OPTYPE1) \
173 OpTypes[OP][0] = OPTYPE0; \
174 OpTypes[OP][1] = OPTYPE1; \
176 #define DECLARE_OP1(OP, OPTYPE0) DECLARE_OP2(OP, OPTYPE0, OT_None)
177 #define DECLARE_OP0(OP) DECLARE_OP1(OP, OT_None)
179 DECLARE_OP1(DW_CFA_set_loc, OT_Address);
180 DECLARE_OP1(DW_CFA_advance_loc, OT_FactoredCodeOffset);
181 DECLARE_OP1(DW_CFA_advance_loc1, OT_FactoredCodeOffset);
182 DECLARE_OP1(DW_CFA_advance_loc2, OT_FactoredCodeOffset);
183 DECLARE_OP1(DW_CFA_advance_loc4, OT_FactoredCodeOffset);
184 DECLARE_OP1(DW_CFA_MIPS_advance_loc8, OT_FactoredCodeOffset);
185 DECLARE_OP2(DW_CFA_def_cfa, OT_Register, OT_Offset);
186 DECLARE_OP2(DW_CFA_def_cfa_sf, OT_Register, OT_SignedFactDataOffset);
187 DECLARE_OP1(DW_CFA_def_cfa_register, OT_Register);
188 DECLARE_OP1(DW_CFA_def_cfa_offset, OT_Offset);
189 DECLARE_OP1(DW_CFA_def_cfa_offset_sf, OT_SignedFactDataOffset);
190 DECLARE_OP1(DW_CFA_def_cfa_expression, OT_Expression);
191 DECLARE_OP1(DW_CFA_undefined, OT_Register);
192 DECLARE_OP1(DW_CFA_same_value, OT_Register);
193 DECLARE_OP2(DW_CFA_offset, OT_Register, OT_UnsignedFactDataOffset);
194 DECLARE_OP2(DW_CFA_offset_extended, OT_Register, OT_UnsignedFactDataOffset);
195 DECLARE_OP2(DW_CFA_offset_extended_sf, OT_Register, OT_SignedFactDataOffset);
196 DECLARE_OP2(DW_CFA_val_offset, OT_Register, OT_UnsignedFactDataOffset);
197 DECLARE_OP2(DW_CFA_val_offset_sf, OT_Register, OT_SignedFactDataOffset);
198 DECLARE_OP2(DW_CFA_register, OT_Register, OT_Register);
199 DECLARE_OP2(DW_CFA_expression, OT_Register, OT_Expression);
200 DECLARE_OP2(DW_CFA_val_expression, OT_Register, OT_Expression);
201 DECLARE_OP1(DW_CFA_restore, OT_Register);
202 DECLARE_OP1(DW_CFA_restore_extended, OT_Register);
203 DECLARE_OP0(DW_CFA_remember_state);
204 DECLARE_OP0(DW_CFA_restore_state);
205 DECLARE_OP0(DW_CFA_GNU_window_save);
206 DECLARE_OP1(DW_CFA_GNU_args_size, OT_Offset);
207 DECLARE_OP0(DW_CFA_nop);
213 return ArrayRef<OperandType[2]>(&OpTypes[0], DW_CFA_restore+1);
216 /// Print \p Opcode's operand number \p OperandIdx which has value \p Operand.
217 void CFIProgram::printOperand(raw_ostream &OS, const MCRegisterInfo *MRI,
218 bool IsEH, const Instruction &Instr,
219 unsigned OperandIdx, uint64_t Operand) const {
220 assert(OperandIdx < 2);
221 uint8_t Opcode = Instr.Opcode;
222 OperandType Type = getOperandTypes()[Opcode][OperandIdx];
226 OS << " Unsupported " << (OperandIdx ? "second" : "first") << " operand to";
227 auto OpcodeName = CallFrameString(Opcode, Arch);
228 if (!OpcodeName.empty())
229 OS << " " << OpcodeName;
231 OS << format(" Opcode %x", Opcode);
237 OS << format(" %" PRIx64, Operand);
240 // The offsets are all encoded in a unsigned form, but in practice
241 // consumers use them signed. It's most certainly legacy due to
242 // the lack of signed variants in the first Dwarf standards.
243 OS << format(" %+" PRId64, int64_t(Operand));
245 case OT_FactoredCodeOffset: // Always Unsigned
246 if (CodeAlignmentFactor)
247 OS << format(" %" PRId64, Operand * CodeAlignmentFactor);
249 OS << format(" %" PRId64 "*code_alignment_factor" , Operand);
251 case OT_SignedFactDataOffset:
252 if (DataAlignmentFactor)
253 OS << format(" %" PRId64, int64_t(Operand) * DataAlignmentFactor);
255 OS << format(" %" PRId64 "*data_alignment_factor" , int64_t(Operand));
257 case OT_UnsignedFactDataOffset:
258 if (DataAlignmentFactor)
259 OS << format(" %" PRId64, Operand * DataAlignmentFactor);
261 OS << format(" %" PRId64 "*data_alignment_factor" , Operand);
264 OS << format(" reg%" PRId64, Operand);
267 assert(Instr.Expression && "missing DWARFExpression object");
269 Instr.Expression->print(OS, MRI, nullptr, IsEH);
274 void CFIProgram::dump(raw_ostream &OS, const MCRegisterInfo *MRI, bool IsEH,
275 unsigned IndentLevel) const {
276 for (const auto &Instr : Instructions) {
277 uint8_t Opcode = Instr.Opcode;
278 if (Opcode & DWARF_CFI_PRIMARY_OPCODE_MASK)
279 Opcode &= DWARF_CFI_PRIMARY_OPCODE_MASK;
280 OS.indent(2 * IndentLevel);
281 OS << CallFrameString(Opcode, Arch) << ":";
282 for (unsigned i = 0; i < Instr.Ops.size(); ++i)
283 printOperand(OS, MRI, IsEH, Instr, i, Instr.Ops[i]);
288 void CIE::dump(raw_ostream &OS, const MCRegisterInfo *MRI, bool IsEH) const {
289 OS << format("%08x %08x %08x CIE", (uint32_t)Offset, (uint32_t)Length,
292 OS << format(" Version: %d\n", Version);
293 OS << " Augmentation: \"" << Augmentation << "\"\n";
295 OS << format(" Address size: %u\n", (uint32_t)AddressSize);
296 OS << format(" Segment desc size: %u\n",
297 (uint32_t)SegmentDescriptorSize);
299 OS << format(" Code alignment factor: %u\n", (uint32_t)CodeAlignmentFactor);
300 OS << format(" Data alignment factor: %d\n", (int32_t)DataAlignmentFactor);
301 OS << format(" Return address column: %d\n", (int32_t)ReturnAddressRegister);
303 OS << format(" Personality Address: %016" PRIx64 "\n", *Personality);
304 if (!AugmentationData.empty()) {
305 OS << " Augmentation data: ";
306 for (uint8_t Byte : AugmentationData)
307 OS << ' ' << hexdigit(Byte >> 4) << hexdigit(Byte & 0xf);
311 CFIs.dump(OS, MRI, IsEH);
315 void FDE::dump(raw_ostream &OS, const MCRegisterInfo *MRI, bool IsEH) const {
316 OS << format("%08x %08x %08x FDE ", (uint32_t)Offset, (uint32_t)Length,
317 (int32_t)LinkedCIEOffset);
318 OS << format("cie=%08x pc=%08x...%08x\n", (int32_t)LinkedCIEOffset,
319 (uint32_t)InitialLocation,
320 (uint32_t)InitialLocation + (uint32_t)AddressRange);
322 OS << format(" LSDA Address: %016" PRIx64 "\n", *LSDAAddress);
323 CFIs.dump(OS, MRI, IsEH);
327 DWARFDebugFrame::DWARFDebugFrame(Triple::ArchType Arch,
328 bool IsEH, uint64_t EHFrameAddress)
329 : Arch(Arch), IsEH(IsEH), EHFrameAddress(EHFrameAddress) {}
331 DWARFDebugFrame::~DWARFDebugFrame() = default;
333 static void LLVM_ATTRIBUTE_UNUSED dumpDataAux(DataExtractor Data,
334 uint32_t Offset, int Length) {
336 for (int i = 0; i < Length; ++i) {
337 uint8_t c = Data.getU8(&Offset);
338 errs().write_hex(c); errs() << " ";
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) {
350 raw_string_ostream OS(Str);
351 OS << format(ErrorMsg, StartOffset);
353 report_fatal_error(Str);
356 void DWARFDebugFrame::parse(DWARFDataExtractor Data) {
358 DenseMap<uint32_t, CIE *> CIEs;
360 while (Data.isValidOffset(Offset)) {
361 uint32_t StartOffset = Offset;
363 bool IsDWARF64 = false;
364 uint64_t Length = Data.getU32(&Offset);
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
372 Length = Data.getU64(&Offset);
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
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);
384 // The Id field's size depends on the DWARF format
385 Id = Data.getUnsigned(&Offset, (IsDWARF64 && !IsEH) ? 8 : 4);
387 ((IsDWARF64 && Id == DW64_CIE_ID) || Id == DW_CIE_ID || (IsEH && !Id));
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() :
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 =
400 Version == 1 ? Data.getU8(&Offset) : Data.getULEB128(&Offset);
402 // Parse the augmentation data for EH CIEs
403 StringRef AugmentationData("");
404 uint32_t FDEPointerEncoding = DW_EH_PE_absptr;
405 uint32_t LSDAPointerEncoding = DW_EH_PE_omit;
406 Optional<uint64_t> Personality;
407 Optional<uint32_t> PersonalityEncoding;
409 Optional<uint64_t> AugmentationLength;
410 uint32_t StartAugmentationOffset;
411 uint32_t EndAugmentationOffset;
413 // Walk the augmentation string to get all the augmentation data.
414 for (unsigned i = 0, e = AugmentationString.size(); i != e; ++i) {
415 switch (AugmentationString[i]) {
417 ReportError(StartOffset,
418 "Unknown augmentation character in entry at %lx");
420 LSDAPointerEncoding = Data.getU8(&Offset);
424 ReportError(StartOffset,
425 "Duplicate personality in entry at %lx");
426 PersonalityEncoding = Data.getU8(&Offset);
427 Personality = Data.getEncodedPointer(
428 &Offset, *PersonalityEncoding,
429 EHFrameAddress ? EHFrameAddress + Offset : 0);
433 FDEPointerEncoding = Data.getU8(&Offset);
436 // Current frame is a signal trampoline.
440 ReportError(StartOffset,
441 "'z' must be the first character at %lx");
442 // Parse the augmentation length first. We only parse it if
443 // the string contains a 'z'.
444 AugmentationLength = Data.getULEB128(&Offset);
445 StartAugmentationOffset = Offset;
446 EndAugmentationOffset = Offset +
447 static_cast<uint32_t>(*AugmentationLength);
450 // B-Key is used for signing functions associated with this
451 // augmentation string
456 if (AugmentationLength.hasValue()) {
457 if (Offset != EndAugmentationOffset)
458 ReportError(StartOffset, "Parsing augmentation data at %lx failed");
460 AugmentationData = Data.getData().slice(StartAugmentationOffset,
461 EndAugmentationOffset);
465 auto Cie = llvm::make_unique<CIE>(
466 StartOffset, Length, Version, AugmentationString, AddressSize,
467 SegmentDescriptorSize, CodeAlignmentFactor, DataAlignmentFactor,
468 ReturnAddressRegister, AugmentationData, FDEPointerEncoding,
469 LSDAPointerEncoding, Personality, PersonalityEncoding, Arch);
470 CIEs[StartOffset] = Cie.get();
471 Entries.emplace_back(std::move(Cie));
474 uint64_t CIEPointer = Id;
475 uint64_t InitialLocation = 0;
476 uint64_t AddressRange = 0;
477 Optional<uint64_t> LSDAAddress;
478 CIE *Cie = CIEs[IsEH ? (StartStructureOffset - CIEPointer) : CIEPointer];
481 // The address size is encoded in the CIE we reference.
483 ReportError(StartOffset,
484 "Parsing FDE data at %lx failed due to missing CIE");
486 if (auto Val = Data.getEncodedPointer(
487 &Offset, Cie->getFDEPointerEncoding(),
488 EHFrameAddress ? EHFrameAddress + Offset : 0)) {
489 InitialLocation = *Val;
491 if (auto Val = Data.getEncodedPointer(
492 &Offset, Cie->getFDEPointerEncoding(), 0)) {
496 StringRef AugmentationString = Cie->getAugmentationString();
497 if (!AugmentationString.empty()) {
498 // Parse the augmentation length and data for this FDE.
499 uint64_t AugmentationLength = Data.getULEB128(&Offset);
501 uint32_t EndAugmentationOffset =
502 Offset + static_cast<uint32_t>(AugmentationLength);
504 // Decode the LSDA if the CIE augmentation string said we should.
505 if (Cie->getLSDAPointerEncoding() != DW_EH_PE_omit) {
506 LSDAAddress = Data.getEncodedPointer(
507 &Offset, Cie->getLSDAPointerEncoding(),
508 EHFrameAddress ? Offset + EHFrameAddress : 0);
511 if (Offset != EndAugmentationOffset)
512 ReportError(StartOffset, "Parsing augmentation data at %lx failed");
515 InitialLocation = Data.getAddress(&Offset);
516 AddressRange = Data.getAddress(&Offset);
519 Entries.emplace_back(new FDE(StartOffset, Length, CIEPointer,
520 InitialLocation, AddressRange,
521 Cie, LSDAAddress, Arch));
525 Entries.back()->cfis().parse(Data, &Offset, EndStructureOffset)) {
526 report_fatal_error(toString(std::move(E)));
529 if (Offset != EndStructureOffset)
530 ReportError(StartOffset, "Parsing entry instructions at %lx failed");
534 FrameEntry *DWARFDebugFrame::getEntryAtOffset(uint64_t Offset) const {
535 auto It = llvm::bsearch(Entries, [=](const std::unique_ptr<FrameEntry> &E) {
536 return Offset <= E->getOffset();
538 if (It != Entries.end() && (*It)->getOffset() == Offset)
543 void DWARFDebugFrame::dump(raw_ostream &OS, const MCRegisterInfo *MRI,
544 Optional<uint64_t> Offset) const {
546 if (auto *Entry = getEntryAtOffset(*Offset))
547 Entry->dump(OS, MRI, IsEH);
552 for (const auto &Entry : Entries)
553 Entry->dump(OS, MRI, IsEH);