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Diffstat (limited to 'lib/DebugInfo/DWARFDebugFrame.cpp')
| -rw-r--r-- | lib/DebugInfo/DWARFDebugFrame.cpp | 195 |
1 files changed, 195 insertions, 0 deletions
diff --git a/lib/DebugInfo/DWARFDebugFrame.cpp b/lib/DebugInfo/DWARFDebugFrame.cpp new file mode 100644 index 0000000000..0b78cce1dd --- /dev/null +++ b/lib/DebugInfo/DWARFDebugFrame.cpp @@ -0,0 +1,195 @@ +//===-- 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 "DWARFDebugFrame.h" +#include "llvm/ADT/SmallString.h" +#include "llvm/Support/DataTypes.h" +#include "llvm/Support/Dwarf.h" +#include "llvm/Support/Format.h" + +using namespace llvm; +using namespace dwarf; + + +class llvm::FrameEntry { +public: + enum FrameKind {FK_CIE, FK_FDE}; + FrameEntry(FrameKind K, DataExtractor D, uint64_t Offset, uint64_t Length) + : Kind(K), Data(D), Offset(Offset), Length(Length) + {} + + FrameKind getKind() const { return Kind; } + + virtual void dumpHeader(raw_ostream &OS) const = 0; +protected: + const FrameKind Kind; + DataExtractor Data; + uint64_t Offset; + uint64_t Length; +}; + + +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(DataExtractor D, uint64_t Offset, uint64_t Length, uint8_t Version, + SmallString<8> Augmentation, uint64_t CodeAlignmentFactor, + int64_t DataAlignmentFactor, uint64_t ReturnAddressRegister) + : FrameEntry(FK_CIE, D, Offset, Length), Version(Version), + Augmentation(Augmentation), CodeAlignmentFactor(CodeAlignmentFactor), + DataAlignmentFactor(DataAlignmentFactor), + ReturnAddressRegister(ReturnAddressRegister) + {} + + void dumpHeader(raw_ostream &OS) const { + OS << format("%08x %08x %08x CIE", Offset, Length, DW_CIE_ID) << "\n"; + OS << format(" Version: %d\n", Version); + OS << " Augmentation: \"" << Augmentation << "\"\n"; + OS << format(" Code alignment factor: %u\n", CodeAlignmentFactor); + OS << format(" Data alignment factor: %d\n", DataAlignmentFactor); + OS << format(" Return address column: %d\n", ReturnAddressRegister); + OS << "\n"; + } + + static bool classof(const FrameEntry *FE) { + return FE->getKind() == FK_CIE; + } +private: + uint8_t Version; + SmallString<8> Augmentation; + uint64_t CodeAlignmentFactor; + int64_t DataAlignmentFactor; + uint64_t ReturnAddressRegister; +}; + + +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(DataExtractor D, uint64_t Offset, uint64_t Length, int64_t LinkedCIEOffset, + uint64_t InitialLocation, uint64_t AddressRange) + : FrameEntry(FK_FDE, D, Offset, Length), LinkedCIEOffset(LinkedCIEOffset), + InitialLocation(InitialLocation), AddressRange(AddressRange), + LinkedCIE(NULL) + {} + + void dumpHeader(raw_ostream &OS) const { + OS << format("%08x %08x %08x FDE ", Offset, Length, LinkedCIEOffset); + OS << format("cie=%08x pc=%08x...%08x\n", + LinkedCIEOffset, InitialLocation, + InitialLocation + AddressRange); + OS << "\n"; + } + + static bool classof(const FrameEntry *FE) { + return FE->getKind() == FK_FDE; + } +private: + uint64_t LinkedCIEOffset; + uint64_t InitialLocation; + uint64_t AddressRange; + CIE *LinkedCIE; +}; + + +DWARFDebugFrame::DWARFDebugFrame() +{ +} + + +DWARFDebugFrame::~DWARFDebugFrame() +{ + for (EntryVector::iterator I = Entries.begin(), E = Entries.end(); + I != E; ++I) { + delete *I; + } +} + + +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; + + 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) { + // Note: this is specifically DWARFv3 CIE header structure. It was + // changed in DWARFv4. + uint8_t Version = Data.getU8(&Offset); + const char *Augmentation = Data.getCStr(&Offset); + uint64_t CodeAlignmentFactor = Data.getULEB128(&Offset); + int64_t DataAlignmentFactor = Data.getSLEB128(&Offset); + uint64_t ReturnAddressRegister = Data.getULEB128(&Offset); + + CIE *NewCIE = new CIE(Data, StartOffset, Length, Version, + StringRef(Augmentation), CodeAlignmentFactor, + DataAlignmentFactor, ReturnAddressRegister); + Entries.push_back(NewCIE); + } else { + // FDE + uint64_t CIEPointer = Id; + uint64_t InitialLocation = Data.getAddress(&Offset); + uint64_t AddressRange = Data.getAddress(&Offset); + + FDE *NewFDE = new FDE(Data, StartOffset, Length, CIEPointer, + InitialLocation, AddressRange); + Entries.push_back(NewFDE); + } + + Offset = EndStructureOffset; + } +} + + +void DWARFDebugFrame::dump(raw_ostream &OS) const { + OS << "\n"; + for (EntryVector::const_iterator I = Entries.begin(), E = Entries.end(); + I != E; ++I) { + (*I)->dumpHeader(OS); + } +} + |