| //===- DWARFDebugFrame.h - Parsing of .debug_frame ------------------------===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "llvm/DebugInfo/DWARF/DWARFDebugFrame.h" |
| #include "llvm/ADT/DenseMap.h" |
| #include "llvm/ADT/StringExtras.h" |
| #include "llvm/ADT/StringRef.h" |
| #include "llvm/BinaryFormat/Dwarf.h" |
| #include "llvm/DebugInfo/DIContext.h" |
| #include "llvm/DebugInfo/DWARF/DWARFCFIPrinter.h" |
| #include "llvm/DebugInfo/DWARF/DWARFDataExtractor.h" |
| #include "llvm/DebugInfo/DWARF/DWARFExpressionPrinter.h" |
| #include "llvm/DebugInfo/DWARF/DWARFUnwindTablePrinter.h" |
| #include "llvm/DebugInfo/DWARF/LowLevel/DWARFCFIProgram.h" |
| #include "llvm/DebugInfo/DWARF/LowLevel/DWARFExpression.h" |
| #include "llvm/Support/Compiler.h" |
| #include "llvm/Support/DataExtractor.h" |
| #include "llvm/Support/Errc.h" |
| #include "llvm/Support/Error.h" |
| #include "llvm/Support/ErrorHandling.h" |
| #include "llvm/Support/Format.h" |
| #include "llvm/Support/raw_ostream.h" |
| #include <cassert> |
| #include <cinttypes> |
| #include <cstdint> |
| #include <optional> |
| |
| using namespace llvm; |
| using namespace dwarf; |
| |
| Expected<UnwindTable> llvm::dwarf::createUnwindTable(const FDE *Fde) { |
| const CIE *Cie = Fde->getLinkedCIE(); |
| if (Cie == nullptr) |
| return createStringError(errc::invalid_argument, |
| "unable to get CIE for FDE at offset 0x%" PRIx64, |
| Fde->getOffset()); |
| |
| // Rows will be empty if there are no CFI instructions. |
| if (Cie->cfis().empty() && Fde->cfis().empty()) |
| return UnwindTable({}); |
| |
| UnwindTable::RowContainer CieRows; |
| UnwindRow Row; |
| Row.setAddress(Fde->getInitialLocation()); |
| if (Error CieError = parseRows(Cie->cfis(), Row, nullptr).moveInto(CieRows)) |
| return std::move(CieError); |
| // We need to save the initial locations of registers from the CIE parsing |
| // in case we run into DW_CFA_restore or DW_CFA_restore_extended opcodes. |
| UnwindTable::RowContainer FdeRows; |
| const RegisterLocations InitialLocs = Row.getRegisterLocations(); |
| if (Error FdeError = |
| parseRows(Fde->cfis(), Row, &InitialLocs).moveInto(FdeRows)) |
| return std::move(FdeError); |
| |
| UnwindTable::RowContainer AllRows; |
| AllRows.insert(AllRows.end(), CieRows.begin(), CieRows.end()); |
| AllRows.insert(AllRows.end(), FdeRows.begin(), FdeRows.end()); |
| |
| // May be all the CFI instructions were DW_CFA_nop amd Row becomes empty. |
| // Do not add that to the unwind table. |
| if (Row.getRegisterLocations().hasLocations() || |
| Row.getCFAValue().getLocation() != UnwindLocation::Unspecified) |
| AllRows.push_back(Row); |
| return UnwindTable(std::move(AllRows)); |
| } |
| |
| Expected<UnwindTable> llvm::dwarf::createUnwindTable(const CIE *Cie) { |
| // Rows will be empty if there are no CFI instructions. |
| if (Cie->cfis().empty()) |
| return UnwindTable({}); |
| |
| UnwindTable::RowContainer Rows; |
| UnwindRow Row; |
| if (Error CieError = parseRows(Cie->cfis(), Row, nullptr).moveInto(Rows)) |
| return std::move(CieError); |
| // May be all the CFI instructions were DW_CFA_nop amd Row becomes empty. |
| // Do not add that to the unwind table. |
| if (Row.getRegisterLocations().hasLocations() || |
| Row.getCFAValue().getLocation() != UnwindLocation::Unspecified) |
| Rows.push_back(Row); |
| return UnwindTable(std::move(Rows)); |
| } |
| |
| // Returns the CIE identifier to be used by the requested format. |
| // CIE ids for .debug_frame sections are defined in Section 7.24 of DWARFv5. |
| // For CIE ID in .eh_frame sections see |
| // https://refspecs.linuxfoundation.org/LSB_5.0.0/LSB-Core-generic/LSB-Core-generic/ehframechpt.html |
| constexpr uint64_t getCIEId(bool IsDWARF64, bool IsEH) { |
| if (IsEH) |
| return 0; |
| if (IsDWARF64) |
| return DW64_CIE_ID; |
| return DW_CIE_ID; |
| } |
| |
| void CIE::dump(raw_ostream &OS, DIDumpOptions DumpOpts) const { |
| // A CIE with a zero length is a terminator entry in the .eh_frame section. |
| if (DumpOpts.IsEH && Length == 0) { |
| OS << format("%08" PRIx64, Offset) << " ZERO terminator\n"; |
| return; |
| } |
| |
| OS << format("%08" PRIx64, Offset) |
| << format(" %0*" PRIx64, IsDWARF64 ? 16 : 8, Length) |
| << format(" %0*" PRIx64, IsDWARF64 && !DumpOpts.IsEH ? 16 : 8, |
| getCIEId(IsDWARF64, DumpOpts.IsEH)) |
| << " CIE\n" |
| << " Format: " << FormatString(IsDWARF64) << "\n"; |
| if (DumpOpts.IsEH && Version != 1) |
| OS << "WARNING: unsupported CIE version\n"; |
| OS << format(" Version: %d\n", Version) |
| << " 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); |
| if (Personality) |
| OS << format(" Personality Address: %016" PRIx64 "\n", *Personality); |
| if (!AugmentationData.empty()) { |
| OS << " Augmentation data: "; |
| for (uint8_t Byte : AugmentationData) |
| OS << ' ' << hexdigit(Byte >> 4) << hexdigit(Byte & 0xf); |
| OS << "\n"; |
| } |
| OS << "\n"; |
| printCFIProgram(CFIs, OS, DumpOpts, /*IndentLevel=*/1, |
| /*InitialLocation=*/{}); |
| OS << "\n"; |
| |
| if (Expected<UnwindTable> RowsOrErr = createUnwindTable(this)) |
| printUnwindTable(*RowsOrErr, OS, DumpOpts, 1); |
| else { |
| DumpOpts.RecoverableErrorHandler(joinErrors( |
| createStringError(errc::invalid_argument, |
| "decoding the CIE opcodes into rows failed"), |
| RowsOrErr.takeError())); |
| } |
| OS << "\n"; |
| } |
| |
| void FDE::dump(raw_ostream &OS, DIDumpOptions DumpOpts) const { |
| OS << format("%08" PRIx64, Offset) |
| << format(" %0*" PRIx64, IsDWARF64 ? 16 : 8, Length) |
| << format(" %0*" PRIx64, IsDWARF64 && !DumpOpts.IsEH ? 16 : 8, CIEPointer) |
| << " FDE cie="; |
| if (LinkedCIE) |
| OS << format("%08" PRIx64, LinkedCIE->getOffset()); |
| else |
| OS << "<invalid offset>"; |
| OS << format(" pc=%08" PRIx64 "...%08" PRIx64 "\n", InitialLocation, |
| InitialLocation + AddressRange); |
| OS << " Format: " << FormatString(IsDWARF64) << "\n"; |
| if (LSDAAddress) |
| OS << format(" LSDA Address: %016" PRIx64 "\n", *LSDAAddress); |
| printCFIProgram(CFIs, OS, DumpOpts, /*IndentLevel=*/1, InitialLocation); |
| OS << "\n"; |
| |
| if (Expected<UnwindTable> RowsOrErr = createUnwindTable(this)) |
| printUnwindTable(*RowsOrErr, OS, DumpOpts, 1); |
| else { |
| DumpOpts.RecoverableErrorHandler(joinErrors( |
| createStringError(errc::invalid_argument, |
| "decoding the FDE opcodes into rows failed"), |
| RowsOrErr.takeError())); |
| } |
| OS << "\n"; |
| } |
| |
| DWARFDebugFrame::DWARFDebugFrame(Triple::ArchType Arch, |
| bool IsEH, uint64_t EHFrameAddress) |
| : Arch(Arch), IsEH(IsEH), EHFrameAddress(EHFrameAddress) {} |
| |
| DWARFDebugFrame::~DWARFDebugFrame() = default; |
| |
| static void LLVM_ATTRIBUTE_UNUSED dumpDataAux(DataExtractor Data, |
| uint64_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"; |
| } |
| |
| Error DWARFDebugFrame::parse(DWARFDataExtractor Data) { |
| uint64_t Offset = 0; |
| DenseMap<uint64_t, CIE *> CIEs; |
| |
| while (Data.isValidOffset(Offset)) { |
| uint64_t StartOffset = Offset; |
| |
| uint64_t Length; |
| DwarfFormat Format; |
| std::tie(Length, Format) = Data.getInitialLength(&Offset); |
| bool IsDWARF64 = Format == DWARF64; |
| |
| // If the Length is 0, then this CIE is a terminator. We add it because some |
| // dumper tools might need it to print something special for such entries |
| // (e.g. llvm-objdump --dwarf=frames prints "ZERO terminator"). |
| if (Length == 0) { |
| auto Cie = std::make_unique<CIE>( |
| IsDWARF64, StartOffset, 0, 0, SmallString<8>(), 0, 0, 0, 0, 0, |
| SmallString<8>(), 0, 0, std::nullopt, std::nullopt, Arch); |
| CIEs[StartOffset] = Cie.get(); |
| Entries.push_back(std::move(Cie)); |
| break; |
| } |
| |
| // 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). |
| uint64_t StartStructureOffset = Offset; |
| uint64_t EndStructureOffset = Offset + Length; |
| |
| // The Id field's size depends on the DWARF format |
| Error Err = Error::success(); |
| uint64_t Id = Data.getRelocatedValue((IsDWARF64 && !IsEH) ? 8 : 4, &Offset, |
| /*SectionIndex=*/nullptr, &Err); |
| if (Err) |
| return Err; |
| |
| if (Id == getCIEId(IsDWARF64, IsEH)) { |
| uint8_t Version = Data.getU8(&Offset); |
| const char *Augmentation = Data.getCStr(&Offset); |
| StringRef AugmentationString(Augmentation ? Augmentation : ""); |
| 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 = |
| Version == 1 ? Data.getU8(&Offset) : Data.getULEB128(&Offset); |
| |
| // Parse the augmentation data for EH CIEs |
| StringRef AugmentationData(""); |
| uint32_t FDEPointerEncoding = DW_EH_PE_absptr; |
| uint32_t LSDAPointerEncoding = DW_EH_PE_omit; |
| std::optional<uint64_t> Personality; |
| std::optional<uint32_t> PersonalityEncoding; |
| if (IsEH) { |
| std::optional<uint64_t> AugmentationLength; |
| uint64_t StartAugmentationOffset; |
| uint64_t EndAugmentationOffset; |
| |
| // Walk the augmentation string to get all the augmentation data. |
| for (unsigned i = 0, e = AugmentationString.size(); i != e; ++i) { |
| switch (AugmentationString[i]) { |
| default: |
| return createStringError( |
| errc::invalid_argument, |
| "unknown augmentation character %c in entry at 0x%" PRIx64, |
| AugmentationString[i], StartOffset); |
| case 'L': |
| LSDAPointerEncoding = Data.getU8(&Offset); |
| break; |
| case 'P': { |
| if (Personality) |
| return createStringError( |
| errc::invalid_argument, |
| "duplicate personality in entry at 0x%" PRIx64, StartOffset); |
| PersonalityEncoding = Data.getU8(&Offset); |
| Personality = Data.getEncodedPointer( |
| &Offset, *PersonalityEncoding, |
| EHFrameAddress ? EHFrameAddress + Offset : 0); |
| break; |
| } |
| case 'R': |
| FDEPointerEncoding = Data.getU8(&Offset); |
| break; |
| case 'S': |
| // Current frame is a signal trampoline. |
| break; |
| case 'z': |
| if (i) |
| return createStringError( |
| errc::invalid_argument, |
| "'z' must be the first character at 0x%" PRIx64, StartOffset); |
| // Parse the augmentation length first. We only parse it if |
| // the string contains a 'z'. |
| AugmentationLength = Data.getULEB128(&Offset); |
| StartAugmentationOffset = Offset; |
| EndAugmentationOffset = Offset + *AugmentationLength; |
| break; |
| case 'B': |
| // B-Key is used for signing functions associated with this |
| // augmentation string |
| break; |
| // This stack frame contains MTE tagged data, so needs to be |
| // untagged on unwind. |
| case 'G': |
| break; |
| } |
| } |
| |
| if (AugmentationLength) { |
| if (Offset != EndAugmentationOffset) |
| return createStringError(errc::invalid_argument, |
| "parsing augmentation data at 0x%" PRIx64 |
| " failed", |
| StartOffset); |
| AugmentationData = Data.getData().slice(StartAugmentationOffset, |
| EndAugmentationOffset); |
| } |
| } |
| |
| auto Cie = std::make_unique<CIE>( |
| IsDWARF64, StartOffset, Length, Version, AugmentationString, |
| AddressSize, SegmentDescriptorSize, CodeAlignmentFactor, |
| DataAlignmentFactor, ReturnAddressRegister, AugmentationData, |
| FDEPointerEncoding, LSDAPointerEncoding, Personality, |
| PersonalityEncoding, Arch); |
| CIEs[StartOffset] = Cie.get(); |
| Entries.emplace_back(std::move(Cie)); |
| } else { |
| // FDE |
| uint64_t CIEPointer = Id; |
| uint64_t InitialLocation = 0; |
| uint64_t AddressRange = 0; |
| std::optional<uint64_t> LSDAAddress; |
| CIE *Cie = CIEs[IsEH ? (StartStructureOffset - CIEPointer) : CIEPointer]; |
| |
| if (IsEH) { |
| // The address size is encoded in the CIE we reference. |
| if (!Cie) |
| return createStringError(errc::invalid_argument, |
| "parsing FDE data at 0x%" PRIx64 |
| " failed due to missing CIE", |
| StartOffset); |
| if (auto Val = |
| Data.getEncodedPointer(&Offset, Cie->getFDEPointerEncoding(), |
| EHFrameAddress + Offset)) { |
| InitialLocation = *Val; |
| } |
| if (auto Val = Data.getEncodedPointer( |
| &Offset, Cie->getFDEPointerEncoding(), 0)) { |
| AddressRange = *Val; |
| } |
| |
| StringRef AugmentationString = Cie->getAugmentationString(); |
| if (!AugmentationString.empty()) { |
| // Parse the augmentation length and data for this FDE. |
| uint64_t AugmentationLength = Data.getULEB128(&Offset); |
| |
| uint64_t EndAugmentationOffset = Offset + AugmentationLength; |
| |
| // Decode the LSDA if the CIE augmentation string said we should. |
| if (Cie->getLSDAPointerEncoding() != DW_EH_PE_omit) { |
| LSDAAddress = Data.getEncodedPointer( |
| &Offset, Cie->getLSDAPointerEncoding(), |
| EHFrameAddress ? Offset + EHFrameAddress : 0); |
| } |
| |
| if (Offset != EndAugmentationOffset) |
| return createStringError(errc::invalid_argument, |
| "parsing augmentation data at 0x%" PRIx64 |
| " failed", |
| StartOffset); |
| } |
| } else { |
| InitialLocation = Data.getRelocatedAddress(&Offset); |
| AddressRange = Data.getRelocatedAddress(&Offset); |
| } |
| |
| Entries.emplace_back(new FDE(IsDWARF64, StartOffset, Length, CIEPointer, |
| InitialLocation, AddressRange, Cie, |
| LSDAAddress, Arch)); |
| } |
| |
| if (Error E = |
| Entries.back()->cfis().parse(Data, &Offset, EndStructureOffset)) |
| return E; |
| |
| if (Offset != EndStructureOffset) |
| return createStringError( |
| errc::invalid_argument, |
| "parsing entry instructions at 0x%" PRIx64 " failed", StartOffset); |
| } |
| |
| return Error::success(); |
| } |
| |
| FrameEntry *DWARFDebugFrame::getEntryAtOffset(uint64_t Offset) const { |
| auto It = partition_point(Entries, [=](const std::unique_ptr<FrameEntry> &E) { |
| return E->getOffset() < Offset; |
| }); |
| if (It != Entries.end() && (*It)->getOffset() == Offset) |
| return It->get(); |
| return nullptr; |
| } |
| |
| void DWARFDebugFrame::dump(raw_ostream &OS, DIDumpOptions DumpOpts, |
| std::optional<uint64_t> Offset) const { |
| DumpOpts.IsEH = IsEH; |
| if (Offset) { |
| if (auto *Entry = getEntryAtOffset(*Offset)) |
| Entry->dump(OS, DumpOpts); |
| return; |
| } |
| |
| OS << "\n"; |
| for (const auto &Entry : Entries) |
| Entry->dump(OS, DumpOpts); |
| } |
