DWARFDebugFrame.cpp revision 90e01ac0ea5bdc6dd6bccd9c59c3acb04e339666
15d1f7b1de12d16ceb2c938c56701a3e8bfa558f7Torne (Richard Coles)//===-- DWARFDebugFrame.h - Parsing of .debug_frame -------------*- C++ -*-===// 25d1f7b1de12d16ceb2c938c56701a3e8bfa558f7Torne (Richard Coles)// 35d1f7b1de12d16ceb2c938c56701a3e8bfa558f7Torne (Richard Coles)// The LLVM Compiler Infrastructure 45d1f7b1de12d16ceb2c938c56701a3e8bfa558f7Torne (Richard Coles)// 55d1f7b1de12d16ceb2c938c56701a3e8bfa558f7Torne (Richard Coles)// This file is distributed under the University of Illinois Open Source 65d1f7b1de12d16ceb2c938c56701a3e8bfa558f7Torne (Richard Coles)// License. See LICENSE.TXT for details. 75d1f7b1de12d16ceb2c938c56701a3e8bfa558f7Torne (Richard Coles)// 85d1f7b1de12d16ceb2c938c56701a3e8bfa558f7Torne (Richard Coles)//===----------------------------------------------------------------------===// 95d1f7b1de12d16ceb2c938c56701a3e8bfa558f7Torne (Richard Coles) 105d1f7b1de12d16ceb2c938c56701a3e8bfa558f7Torne (Richard Coles)#include "DWARFDebugFrame.h" 115d1f7b1de12d16ceb2c938c56701a3e8bfa558f7Torne (Richard Coles)#include "llvm/ADT/SmallString.h" 125d1f7b1de12d16ceb2c938c56701a3e8bfa558f7Torne (Richard Coles)#include "llvm/Support/DataTypes.h" 135d1f7b1de12d16ceb2c938c56701a3e8bfa558f7Torne (Richard Coles)#include "llvm/Support/Dwarf.h" 145d1f7b1de12d16ceb2c938c56701a3e8bfa558f7Torne (Richard Coles)#include "llvm/Support/Format.h" 155d1f7b1de12d16ceb2c938c56701a3e8bfa558f7Torne (Richard Coles) 165d1f7b1de12d16ceb2c938c56701a3e8bfa558f7Torne (Richard Coles)using namespace llvm; 175d1f7b1de12d16ceb2c938c56701a3e8bfa558f7Torne (Richard Coles)using namespace dwarf; 185d1f7b1de12d16ceb2c938c56701a3e8bfa558f7Torne (Richard Coles) 195d1f7b1de12d16ceb2c938c56701a3e8bfa558f7Torne (Richard Coles) 205d1f7b1de12d16ceb2c938c56701a3e8bfa558f7Torne (Richard Coles)/// \brief Abstract frame entry defining the common interface concrete 215d1f7b1de12d16ceb2c938c56701a3e8bfa558f7Torne (Richard Coles)/// entries implement. 225d1f7b1de12d16ceb2c938c56701a3e8bfa558f7Torne (Richard Coles)class llvm::FrameEntry { 235d1f7b1de12d16ceb2c938c56701a3e8bfa558f7Torne (Richard Coles)public: 245d1f7b1de12d16ceb2c938c56701a3e8bfa558f7Torne (Richard Coles) enum FrameKind {FK_CIE, FK_FDE}; 255d1f7b1de12d16ceb2c938c56701a3e8bfa558f7Torne (Richard Coles) FrameEntry(FrameKind K, DataExtractor D, uint64_t Offset, uint64_t Length) 265d1f7b1de12d16ceb2c938c56701a3e8bfa558f7Torne (Richard Coles) : Kind(K), Data(D), Offset(Offset), Length(Length) {} 275d1f7b1de12d16ceb2c938c56701a3e8bfa558f7Torne (Richard Coles) 285d1f7b1de12d16ceb2c938c56701a3e8bfa558f7Torne (Richard Coles) virtual ~FrameEntry() { 295d1f7b1de12d16ceb2c938c56701a3e8bfa558f7Torne (Richard Coles) } 305d1f7b1de12d16ceb2c938c56701a3e8bfa558f7Torne (Richard Coles) 315d1f7b1de12d16ceb2c938c56701a3e8bfa558f7Torne (Richard Coles) FrameKind getKind() const { return Kind; } 325d1f7b1de12d16ceb2c938c56701a3e8bfa558f7Torne (Richard Coles) 335d1f7b1de12d16ceb2c938c56701a3e8bfa558f7Torne (Richard Coles) virtual void dumpHeader(raw_ostream &OS) const = 0; 345d1f7b1de12d16ceb2c938c56701a3e8bfa558f7Torne (Richard Coles) 355d1f7b1de12d16ceb2c938c56701a3e8bfa558f7Torne (Richard Coles)protected: 365d1f7b1de12d16ceb2c938c56701a3e8bfa558f7Torne (Richard Coles) const FrameKind Kind; 375d1f7b1de12d16ceb2c938c56701a3e8bfa558f7Torne (Richard Coles) 385d1f7b1de12d16ceb2c938c56701a3e8bfa558f7Torne (Richard Coles) /// \brief The data stream holding the section from which the entry was 39 /// parsed. 40 DataExtractor Data; 41 42 /// \brief Offset of this entry in the section. 43 uint64_t Offset; 44 45 /// \brief Entry length as specified in DWARF. 46 uint64_t Length; 47}; 48 49 50/// \brief DWARF Common Information Entry (CIE) 51class CIE : public FrameEntry { 52public: 53 // CIEs (and FDEs) are simply container classes, so the only sensible way to 54 // create them is by providing the full parsed contents in the constructor. 55 CIE(DataExtractor D, uint64_t Offset, uint64_t Length, uint8_t Version, 56 SmallString<8> Augmentation, uint64_t CodeAlignmentFactor, 57 int64_t DataAlignmentFactor, uint64_t ReturnAddressRegister) 58 : FrameEntry(FK_CIE, D, Offset, Length), Version(Version), 59 Augmentation(Augmentation), CodeAlignmentFactor(CodeAlignmentFactor), 60 DataAlignmentFactor(DataAlignmentFactor), 61 ReturnAddressRegister(ReturnAddressRegister) {} 62 63 ~CIE() { 64 } 65 66 void dumpHeader(raw_ostream &OS) const { 67 OS << format("%08x %08x %08x CIE", 68 (uint32_t)Offset, (uint32_t)Length, DW_CIE_ID) 69 << "\n"; 70 OS << format(" Version: %d\n", Version); 71 OS << " Augmentation: \"" << Augmentation << "\"\n"; 72 OS << format(" Code alignment factor: %u\n", CodeAlignmentFactor); 73 OS << format(" Data alignment factor: %d\n", DataAlignmentFactor); 74 OS << format(" Return address column: %d\n", ReturnAddressRegister); 75 OS << "\n"; 76 } 77 78 static bool classof(const FrameEntry *FE) { 79 return FE->getKind() == FK_CIE; 80 } 81 82private: 83 /// The following fields are defined in section 6.4.1 of the DWARF standard v3 84 uint8_t Version; 85 SmallString<8> Augmentation; 86 uint64_t CodeAlignmentFactor; 87 int64_t DataAlignmentFactor; 88 uint64_t ReturnAddressRegister; 89}; 90 91 92/// \brief DWARF Frame Description Entry (FDE) 93class FDE : public FrameEntry { 94public: 95 // Each FDE has a CIE it's "linked to". Our FDE contains is constructed with 96 // an offset to the CIE (provided by parsing the FDE header). The CIE itself 97 // is obtained lazily once it's actually required. 98 FDE(DataExtractor D, uint64_t Offset, uint64_t Length, 99 int64_t LinkedCIEOffset, uint64_t InitialLocation, uint64_t AddressRange) 100 : FrameEntry(FK_FDE, D, Offset, Length), LinkedCIEOffset(LinkedCIEOffset), 101 InitialLocation(InitialLocation), AddressRange(AddressRange), 102 LinkedCIE(NULL) {} 103 104 ~FDE() { 105 } 106 107 void dumpHeader(raw_ostream &OS) const { 108 OS << format("%08x %08x %08x FDE ", 109 (uint32_t)Offset, (uint32_t)Length, LinkedCIEOffset); 110 OS << format("cie=%08x pc=%08x...%08x\n", 111 (uint32_t)LinkedCIEOffset, (uint32_t)InitialLocation, 112 InitialLocation + AddressRange); 113 OS << "\n"; 114 if (LinkedCIE) { 115 OS << format("%p\n", LinkedCIE); 116 } 117 } 118 119 static bool classof(const FrameEntry *FE) { 120 return FE->getKind() == FK_FDE; 121 } 122private: 123 124 /// The following fields are defined in section 6.4.1 of the DWARF standard v3 125 uint64_t LinkedCIEOffset; 126 uint64_t InitialLocation; 127 uint64_t AddressRange; 128 CIE *LinkedCIE; 129}; 130 131 132DWARFDebugFrame::DWARFDebugFrame() { 133} 134 135 136DWARFDebugFrame::~DWARFDebugFrame() { 137 for (EntryVector::iterator I = Entries.begin(), E = Entries.end(); 138 I != E; ++I) { 139 delete *I; 140 } 141} 142 143 144static void LLVM_ATTRIBUTE_UNUSED dumpDataAux(DataExtractor Data, 145 uint32_t Offset, int Length) { 146 errs() << "DUMP: "; 147 for (int i = 0; i < Length; ++i) { 148 uint8_t c = Data.getU8(&Offset); 149 errs().write_hex(c); errs() << " "; 150 } 151 errs() << "\n"; 152} 153 154 155void DWARFDebugFrame::parse(DataExtractor Data) { 156 uint32_t Offset = 0; 157 158 while (Data.isValidOffset(Offset)) { 159 uint32_t StartOffset = Offset; 160 161 bool IsDWARF64 = false; 162 uint64_t Length = Data.getU32(&Offset); 163 uint64_t Id; 164 165 if (Length == UINT32_MAX) { 166 // DWARF-64 is distinguished by the first 32 bits of the initial length 167 // field being 0xffffffff. Then, the next 64 bits are the actual entry 168 // length. 169 IsDWARF64 = true; 170 Length = Data.getU64(&Offset); 171 } 172 173 // At this point, Offset points to the next field after Length. 174 // Length is the structure size excluding itself. Compute an offset one 175 // past the end of the structure (needed to know how many instructions to 176 // read). 177 // TODO: For honest DWARF64 support, DataExtractor will have to treat 178 // offset_ptr as uint64_t* 179 uint32_t EndStructureOffset = Offset + static_cast<uint32_t>(Length); 180 181 // The Id field's size depends on the DWARF format 182 Id = Data.getUnsigned(&Offset, IsDWARF64 ? 8 : 4); 183 bool IsCIE = ((IsDWARF64 && Id == DW64_CIE_ID) || Id == DW_CIE_ID); 184 185 if (IsCIE) { 186 // Note: this is specifically DWARFv3 CIE header structure. It was 187 // changed in DWARFv4. 188 uint8_t Version = Data.getU8(&Offset); 189 const char *Augmentation = Data.getCStr(&Offset); 190 uint64_t CodeAlignmentFactor = Data.getULEB128(&Offset); 191 int64_t DataAlignmentFactor = Data.getSLEB128(&Offset); 192 uint64_t ReturnAddressRegister = Data.getULEB128(&Offset); 193 194 CIE *NewCIE = new CIE(Data, StartOffset, Length, Version, 195 StringRef(Augmentation), CodeAlignmentFactor, 196 DataAlignmentFactor, ReturnAddressRegister); 197 Entries.push_back(NewCIE); 198 } else { 199 // FDE 200 uint64_t CIEPointer = Id; 201 uint64_t InitialLocation = Data.getAddress(&Offset); 202 uint64_t AddressRange = Data.getAddress(&Offset); 203 204 FDE *NewFDE = new FDE(Data, StartOffset, Length, CIEPointer, 205 InitialLocation, AddressRange); 206 Entries.push_back(NewFDE); 207 } 208 209 Offset = EndStructureOffset; 210 } 211} 212 213 214void DWARFDebugFrame::dump(raw_ostream &OS) const { 215 OS << "\n"; 216 for (EntryVector::const_iterator I = Entries.begin(), E = Entries.end(); 217 I != E; ++I) { 218 (*I)->dumpHeader(OS); 219 } 220} 221 222