| //===-- DWARFDebugFrame.h - Parsing of .debug_frame -------------*- C++ -*-===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "llvm/DebugInfo/DWARF/DWARFDebugFrame.h" |
| #include "llvm/ADT/ArrayRef.h" |
| #include "llvm/ADT/DenseMap.h" |
| #include "llvm/ADT/SmallString.h" |
| #include "llvm/Support/Casting.h" |
| #include "llvm/Support/DataTypes.h" |
| #include "llvm/Support/Dwarf.h" |
| #include "llvm/Support/ErrorHandling.h" |
| #include "llvm/Support/Format.h" |
| #include "llvm/Support/raw_ostream.h" |
| #include <string> |
| #include <vector> |
| |
| using namespace llvm; |
| using namespace dwarf; |
| |
| |
| /// \brief Abstract frame entry defining the common interface concrete |
| /// entries implement. |
| class llvm::FrameEntry { |
| public: |
| enum FrameKind {FK_CIE, FK_FDE}; |
| FrameEntry(FrameKind K, uint64_t Offset, uint64_t Length) |
| : Kind(K), Offset(Offset), Length(Length) {} |
| |
| virtual ~FrameEntry() { |
| } |
| |
| FrameKind getKind() const { return Kind; } |
| virtual uint64_t getOffset() const { return Offset; } |
| |
| /// \brief Parse and store a sequence of CFI instructions from Data, |
| /// starting at *Offset and ending at EndOffset. If everything |
| /// goes well, *Offset should be equal to EndOffset when this method |
| /// returns. Otherwise, an error occurred. |
| virtual void parseInstructions(DataExtractor Data, uint32_t *Offset, |
| uint32_t EndOffset); |
| |
| /// \brief Dump the entry header to the given output stream. |
| virtual void dumpHeader(raw_ostream &OS) const = 0; |
| |
| /// \brief Dump the entry's instructions to the given output stream. |
| virtual void dumpInstructions(raw_ostream &OS) const; |
| |
| protected: |
| const FrameKind Kind; |
| |
| /// \brief Offset of this entry in the section. |
| uint64_t Offset; |
| |
| /// \brief Entry length as specified in DWARF. |
| uint64_t Length; |
| |
| /// An entry may contain CFI instructions. An instruction consists of an |
| /// opcode and an optional sequence of operands. |
| typedef std::vector<uint64_t> Operands; |
| struct Instruction { |
| Instruction(uint8_t Opcode) |
| : Opcode(Opcode) |
| {} |
| |
| uint8_t Opcode; |
| Operands Ops; |
| }; |
| |
| std::vector<Instruction> Instructions; |
| |
| /// Convenience methods to add a new instruction with the given opcode and |
| /// operands to the Instructions vector. |
| void addInstruction(uint8_t Opcode) { |
| Instructions.push_back(Instruction(Opcode)); |
| } |
| |
| void addInstruction(uint8_t Opcode, uint64_t Operand1) { |
| Instructions.push_back(Instruction(Opcode)); |
| Instructions.back().Ops.push_back(Operand1); |
| } |
| |
| void addInstruction(uint8_t Opcode, uint64_t Operand1, uint64_t Operand2) { |
| Instructions.push_back(Instruction(Opcode)); |
| Instructions.back().Ops.push_back(Operand1); |
| Instructions.back().Ops.push_back(Operand2); |
| } |
| }; |
| |
| |
| // See DWARF standard v3, section 7.23 |
| const uint8_t DWARF_CFI_PRIMARY_OPCODE_MASK = 0xc0; |
| const uint8_t DWARF_CFI_PRIMARY_OPERAND_MASK = 0x3f; |
| |
| void FrameEntry::parseInstructions(DataExtractor Data, uint32_t *Offset, |
| uint32_t EndOffset) { |
| while (*Offset < EndOffset) { |
| uint8_t Opcode = Data.getU8(Offset); |
| // Some instructions have a primary opcode encoded in the top bits. |
| uint8_t Primary = Opcode & DWARF_CFI_PRIMARY_OPCODE_MASK; |
| |
| if (Primary) { |
| // If it's a primary opcode, the first operand is encoded in the bottom |
| // bits of the opcode itself. |
| uint64_t Op1 = Opcode & DWARF_CFI_PRIMARY_OPERAND_MASK; |
| switch (Primary) { |
| default: llvm_unreachable("Impossible primary CFI opcode"); |
| case DW_CFA_advance_loc: |
| case DW_CFA_restore: |
| addInstruction(Primary, Op1); |
| break; |
| case DW_CFA_offset: |
| addInstruction(Primary, Op1, Data.getULEB128(Offset)); |
| break; |
| } |
| } else { |
| // Extended opcode - its value is Opcode itself. |
| switch (Opcode) { |
| default: llvm_unreachable("Invalid extended CFI opcode"); |
| case DW_CFA_nop: |
| case DW_CFA_remember_state: |
| case DW_CFA_restore_state: |
| case DW_CFA_GNU_window_save: |
| // No operands |
| addInstruction(Opcode); |
| break; |
| case DW_CFA_set_loc: |
| // Operands: Address |
| addInstruction(Opcode, Data.getAddress(Offset)); |
| break; |
| case DW_CFA_advance_loc1: |
| // Operands: 1-byte delta |
| addInstruction(Opcode, Data.getU8(Offset)); |
| break; |
| case DW_CFA_advance_loc2: |
| // Operands: 2-byte delta |
| addInstruction(Opcode, Data.getU16(Offset)); |
| break; |
| case DW_CFA_advance_loc4: |
| // Operands: 4-byte delta |
| addInstruction(Opcode, Data.getU32(Offset)); |
| break; |
| case DW_CFA_restore_extended: |
| case DW_CFA_undefined: |
| case DW_CFA_same_value: |
| case DW_CFA_def_cfa_register: |
| case DW_CFA_def_cfa_offset: |
| // Operands: ULEB128 |
| addInstruction(Opcode, Data.getULEB128(Offset)); |
| break; |
| case DW_CFA_def_cfa_offset_sf: |
| // Operands: SLEB128 |
| addInstruction(Opcode, Data.getSLEB128(Offset)); |
| break; |
| case DW_CFA_offset_extended: |
| case DW_CFA_register: |
| case DW_CFA_def_cfa: |
| case DW_CFA_val_offset: |
| // Operands: ULEB128, ULEB128 |
| addInstruction(Opcode, Data.getULEB128(Offset), |
| Data.getULEB128(Offset)); |
| break; |
| case DW_CFA_offset_extended_sf: |
| case DW_CFA_def_cfa_sf: |
| case DW_CFA_val_offset_sf: |
| // Operands: ULEB128, SLEB128 |
| addInstruction(Opcode, Data.getULEB128(Offset), |
| Data.getSLEB128(Offset)); |
| break; |
| case DW_CFA_def_cfa_expression: |
| case DW_CFA_expression: |
| case DW_CFA_val_expression: |
| // TODO: implement this |
| report_fatal_error("Values with expressions not implemented yet!"); |
| } |
| } |
| } |
| } |
| |
| namespace { |
| /// \brief DWARF Common Information Entry (CIE) |
| class CIE : public FrameEntry { |
| public: |
| // CIEs (and FDEs) are simply container classes, so the only sensible way to |
| // create them is by providing the full parsed contents in the constructor. |
| CIE(uint64_t Offset, uint64_t Length, uint8_t Version, |
| SmallString<8> Augmentation, uint8_t AddressSize, |
| uint8_t SegmentDescriptorSize, uint64_t CodeAlignmentFactor, |
| int64_t DataAlignmentFactor, uint64_t ReturnAddressRegister) |
| : FrameEntry(FK_CIE, Offset, Length), Version(Version), |
| Augmentation(std::move(Augmentation)), |
| AddressSize(AddressSize), |
| SegmentDescriptorSize(SegmentDescriptorSize), |
| CodeAlignmentFactor(CodeAlignmentFactor), |
| DataAlignmentFactor(DataAlignmentFactor), |
| ReturnAddressRegister(ReturnAddressRegister) {} |
| |
| ~CIE() override {} |
| |
| uint64_t getCodeAlignmentFactor() const { return CodeAlignmentFactor; } |
| int64_t getDataAlignmentFactor() const { return DataAlignmentFactor; } |
| |
| void dumpHeader(raw_ostream &OS) const override { |
| OS << format("%08x %08x %08x CIE", |
| (uint32_t)Offset, (uint32_t)Length, DW_CIE_ID) |
| << "\n"; |
| OS << format(" Version: %d\n", Version); |
| OS << " Augmentation: \"" << Augmentation << "\"\n"; |
| if (Version >= 4) { |
| OS << format(" Address size: %u\n", |
| (uint32_t)AddressSize); |
| OS << format(" Segment desc size: %u\n", |
| (uint32_t)SegmentDescriptorSize); |
| } |
| OS << format(" Code alignment factor: %u\n", |
| (uint32_t)CodeAlignmentFactor); |
| OS << format(" Data alignment factor: %d\n", |
| (int32_t)DataAlignmentFactor); |
| OS << format(" Return address column: %d\n", |
| (int32_t)ReturnAddressRegister); |
| OS << "\n"; |
| } |
| |
| static bool classof(const FrameEntry *FE) { |
| return FE->getKind() == FK_CIE; |
| } |
| |
| private: |
| /// The following fields are defined in section 6.4.1 of the DWARF standard v4 |
| uint8_t Version; |
| SmallString<8> Augmentation; |
| uint8_t AddressSize; |
| uint8_t SegmentDescriptorSize; |
| uint64_t CodeAlignmentFactor; |
| int64_t DataAlignmentFactor; |
| uint64_t ReturnAddressRegister; |
| }; |
| |
| |
| /// \brief DWARF Frame Description Entry (FDE) |
| class FDE : public FrameEntry { |
| public: |
| // Each FDE has a CIE it's "linked to". Our FDE contains is constructed with |
| // an offset to the CIE (provided by parsing the FDE header). The CIE itself |
| // is obtained lazily once it's actually required. |
| FDE(uint64_t Offset, uint64_t Length, int64_t LinkedCIEOffset, |
| uint64_t InitialLocation, uint64_t AddressRange, |
| CIE *Cie) |
| : FrameEntry(FK_FDE, Offset, Length), LinkedCIEOffset(LinkedCIEOffset), |
| InitialLocation(InitialLocation), AddressRange(AddressRange), |
| LinkedCIE(Cie) {} |
| |
| ~FDE() override {} |
| |
| CIE *getLinkedCIE() const { return LinkedCIE; } |
| |
| void dumpHeader(raw_ostream &OS) const override { |
| OS << format("%08x %08x %08x FDE ", |
| (uint32_t)Offset, (uint32_t)Length, (int32_t)LinkedCIEOffset); |
| OS << format("cie=%08x pc=%08x...%08x\n", |
| (int32_t)LinkedCIEOffset, |
| (uint32_t)InitialLocation, |
| (uint32_t)InitialLocation + (uint32_t)AddressRange); |
| } |
| |
| static bool classof(const FrameEntry *FE) { |
| return FE->getKind() == FK_FDE; |
| } |
| |
| private: |
| /// The following fields are defined in section 6.4.1 of the DWARF standard v3 |
| uint64_t LinkedCIEOffset; |
| uint64_t InitialLocation; |
| uint64_t AddressRange; |
| CIE *LinkedCIE; |
| }; |
| |
| /// \brief Types of operands to CF instructions. |
| enum OperandType { |
| OT_Unset, |
| OT_None, |
| OT_Address, |
| OT_Offset, |
| OT_FactoredCodeOffset, |
| OT_SignedFactDataOffset, |
| OT_UnsignedFactDataOffset, |
| OT_Register, |
| OT_Expression |
| }; |
| |
| } // end anonymous namespace |
| |
| /// \brief Initialize the array describing the types of operands. |
| static ArrayRef<OperandType[2]> getOperandTypes() { |
| static OperandType OpTypes[DW_CFA_restore+1][2]; |
| |
| #define DECLARE_OP2(OP, OPTYPE0, OPTYPE1) \ |
| do { \ |
| OpTypes[OP][0] = OPTYPE0; \ |
| OpTypes[OP][1] = OPTYPE1; \ |
| } while (0) |
| #define DECLARE_OP1(OP, OPTYPE0) DECLARE_OP2(OP, OPTYPE0, OT_None) |
| #define DECLARE_OP0(OP) DECLARE_OP1(OP, OT_None) |
| |
| DECLARE_OP1(DW_CFA_set_loc, OT_Address); |
| DECLARE_OP1(DW_CFA_advance_loc, OT_FactoredCodeOffset); |
| DECLARE_OP1(DW_CFA_advance_loc1, OT_FactoredCodeOffset); |
| DECLARE_OP1(DW_CFA_advance_loc2, OT_FactoredCodeOffset); |
| DECLARE_OP1(DW_CFA_advance_loc4, OT_FactoredCodeOffset); |
| DECLARE_OP1(DW_CFA_MIPS_advance_loc8, OT_FactoredCodeOffset); |
| DECLARE_OP2(DW_CFA_def_cfa, OT_Register, OT_Offset); |
| DECLARE_OP2(DW_CFA_def_cfa_sf, OT_Register, OT_SignedFactDataOffset); |
| DECLARE_OP1(DW_CFA_def_cfa_register, OT_Register); |
| DECLARE_OP1(DW_CFA_def_cfa_offset, OT_Offset); |
| DECLARE_OP1(DW_CFA_def_cfa_offset_sf, OT_SignedFactDataOffset); |
| DECLARE_OP1(DW_CFA_def_cfa_expression, OT_Expression); |
| DECLARE_OP1(DW_CFA_undefined, OT_Register); |
| DECLARE_OP1(DW_CFA_same_value, OT_Register); |
| DECLARE_OP2(DW_CFA_offset, OT_Register, OT_UnsignedFactDataOffset); |
| DECLARE_OP2(DW_CFA_offset_extended, OT_Register, OT_UnsignedFactDataOffset); |
| DECLARE_OP2(DW_CFA_offset_extended_sf, OT_Register, OT_SignedFactDataOffset); |
| DECLARE_OP2(DW_CFA_val_offset, OT_Register, OT_UnsignedFactDataOffset); |
| DECLARE_OP2(DW_CFA_val_offset_sf, OT_Register, OT_SignedFactDataOffset); |
| DECLARE_OP2(DW_CFA_register, OT_Register, OT_Register); |
| DECLARE_OP2(DW_CFA_expression, OT_Register, OT_Expression); |
| DECLARE_OP2(DW_CFA_val_expression, OT_Register, OT_Expression); |
| DECLARE_OP1(DW_CFA_restore, OT_Register); |
| DECLARE_OP1(DW_CFA_restore_extended, OT_Register); |
| DECLARE_OP0(DW_CFA_remember_state); |
| DECLARE_OP0(DW_CFA_restore_state); |
| DECLARE_OP0(DW_CFA_GNU_window_save); |
| DECLARE_OP1(DW_CFA_GNU_args_size, OT_Offset); |
| DECLARE_OP0(DW_CFA_nop); |
| |
| #undef DECLARE_OP0 |
| #undef DECLARE_OP1 |
| #undef DECLARE_OP2 |
| return ArrayRef<OperandType[2]>(&OpTypes[0], DW_CFA_restore+1); |
| } |
| |
| static ArrayRef<OperandType[2]> OpTypes = getOperandTypes(); |
| |
| /// \brief Print \p Opcode's operand number \p OperandIdx which has |
| /// value \p Operand. |
| static void printOperand(raw_ostream &OS, uint8_t Opcode, unsigned OperandIdx, |
| uint64_t Operand, uint64_t CodeAlignmentFactor, |
| int64_t DataAlignmentFactor) { |
| assert(OperandIdx < 2); |
| OperandType Type = OpTypes[Opcode][OperandIdx]; |
| |
| switch (Type) { |
| case OT_Unset: |
| OS << " Unsupported " << (OperandIdx ? "second" : "first") << " operand to"; |
| if (const char *OpcodeName = CallFrameString(Opcode)) |
| OS << " " << OpcodeName; |
| else |
| OS << format(" Opcode %x", Opcode); |
| break; |
| case OT_None: |
| break; |
| case OT_Address: |
| OS << format(" %" PRIx64, Operand); |
| break; |
| case OT_Offset: |
| // The offsets are all encoded in a unsigned form, but in practice |
| // consumers use them signed. It's most certainly legacy due to |
| // the lack of signed variants in the first Dwarf standards. |
| OS << format(" %+" PRId64, int64_t(Operand)); |
| break; |
| case OT_FactoredCodeOffset: // Always Unsigned |
| if (CodeAlignmentFactor) |
| OS << format(" %" PRId64, Operand * CodeAlignmentFactor); |
| else |
| OS << format(" %" PRId64 "*code_alignment_factor" , Operand); |
| break; |
| case OT_SignedFactDataOffset: |
| if (DataAlignmentFactor) |
| OS << format(" %" PRId64, int64_t(Operand) * DataAlignmentFactor); |
| else |
| OS << format(" %" PRId64 "*data_alignment_factor" , int64_t(Operand)); |
| break; |
| case OT_UnsignedFactDataOffset: |
| if (DataAlignmentFactor) |
| OS << format(" %" PRId64, Operand * DataAlignmentFactor); |
| else |
| OS << format(" %" PRId64 "*data_alignment_factor" , Operand); |
| break; |
| case OT_Register: |
| OS << format(" reg%" PRId64, Operand); |
| break; |
| case OT_Expression: |
| OS << " expression"; |
| break; |
| } |
| } |
| |
| void FrameEntry::dumpInstructions(raw_ostream &OS) const { |
| uint64_t CodeAlignmentFactor = 0; |
| int64_t DataAlignmentFactor = 0; |
| const CIE *Cie = dyn_cast<CIE>(this); |
| |
| if (!Cie) |
| Cie = cast<FDE>(this)->getLinkedCIE(); |
| if (Cie) { |
| CodeAlignmentFactor = Cie->getCodeAlignmentFactor(); |
| DataAlignmentFactor = Cie->getDataAlignmentFactor(); |
| } |
| |
| for (const auto &Instr : Instructions) { |
| uint8_t Opcode = Instr.Opcode; |
| if (Opcode & DWARF_CFI_PRIMARY_OPCODE_MASK) |
| Opcode &= DWARF_CFI_PRIMARY_OPCODE_MASK; |
| OS << " " << CallFrameString(Opcode) << ":"; |
| for (unsigned i = 0; i < Instr.Ops.size(); ++i) |
| printOperand(OS, Opcode, i, Instr.Ops[i], CodeAlignmentFactor, |
| DataAlignmentFactor); |
| OS << '\n'; |
| } |
| } |
| |
| DWARFDebugFrame::DWARFDebugFrame() { |
| } |
| |
| DWARFDebugFrame::~DWARFDebugFrame() { |
| } |
| |
| static void LLVM_ATTRIBUTE_UNUSED dumpDataAux(DataExtractor Data, |
| uint32_t Offset, int Length) { |
| errs() << "DUMP: "; |
| for (int i = 0; i < Length; ++i) { |
| uint8_t c = Data.getU8(&Offset); |
| errs().write_hex(c); errs() << " "; |
| } |
| errs() << "\n"; |
| } |
| |
| |
| void DWARFDebugFrame::parse(DataExtractor Data) { |
| uint32_t Offset = 0; |
| DenseMap<uint32_t, CIE *> CIEs; |
| |
| while (Data.isValidOffset(Offset)) { |
| uint32_t StartOffset = Offset; |
| |
| bool IsDWARF64 = false; |
| uint64_t Length = Data.getU32(&Offset); |
| uint64_t Id; |
| |
| if (Length == UINT32_MAX) { |
| // DWARF-64 is distinguished by the first 32 bits of the initial length |
| // field being 0xffffffff. Then, the next 64 bits are the actual entry |
| // length. |
| IsDWARF64 = true; |
| Length = Data.getU64(&Offset); |
| } |
| |
| // At this point, Offset points to the next field after Length. |
| // Length is the structure size excluding itself. Compute an offset one |
| // past the end of the structure (needed to know how many instructions to |
| // read). |
| // TODO: For honest DWARF64 support, DataExtractor will have to treat |
| // offset_ptr as uint64_t* |
| uint32_t EndStructureOffset = Offset + static_cast<uint32_t>(Length); |
| |
| // The Id field's size depends on the DWARF format |
| Id = Data.getUnsigned(&Offset, IsDWARF64 ? 8 : 4); |
| bool IsCIE = ((IsDWARF64 && Id == DW64_CIE_ID) || Id == DW_CIE_ID); |
| |
| if (IsCIE) { |
| uint8_t Version = Data.getU8(&Offset); |
| const char *Augmentation = Data.getCStr(&Offset); |
| uint8_t AddressSize = Version < 4 ? Data.getAddressSize() : Data.getU8(&Offset); |
| Data.setAddressSize(AddressSize); |
| uint8_t SegmentDescriptorSize = Version < 4 ? 0 : Data.getU8(&Offset); |
| uint64_t CodeAlignmentFactor = Data.getULEB128(&Offset); |
| int64_t DataAlignmentFactor = Data.getSLEB128(&Offset); |
| uint64_t ReturnAddressRegister = Data.getULEB128(&Offset); |
| |
| auto Cie = make_unique<CIE>(StartOffset, Length, Version, |
| StringRef(Augmentation), AddressSize, |
| SegmentDescriptorSize, CodeAlignmentFactor, |
| DataAlignmentFactor, ReturnAddressRegister); |
| CIEs[StartOffset] = Cie.get(); |
| Entries.emplace_back(std::move(Cie)); |
| } else { |
| // FDE |
| uint64_t CIEPointer = Id; |
| uint64_t InitialLocation = Data.getAddress(&Offset); |
| uint64_t AddressRange = Data.getAddress(&Offset); |
| |
| Entries.emplace_back(new FDE(StartOffset, Length, CIEPointer, |
| InitialLocation, AddressRange, |
| CIEs[CIEPointer])); |
| } |
| |
| Entries.back()->parseInstructions(Data, &Offset, EndStructureOffset); |
| |
| if (Offset != EndStructureOffset) { |
| std::string Str; |
| raw_string_ostream OS(Str); |
| OS << format("Parsing entry instructions at %lx failed", StartOffset); |
| report_fatal_error(Str); |
| } |
| } |
| } |
| |
| |
| void DWARFDebugFrame::dump(raw_ostream &OS) const { |
| OS << "\n"; |
| for (const auto &Entry : Entries) { |
| Entry->dumpHeader(OS); |
| Entry->dumpInstructions(OS); |
| OS << "\n"; |
| } |
| } |
| |
