1 //===- DWARFDebugInfoEntry.cpp --------------------------------------------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 10 #include "llvm/DebugInfo/DWARF/DWARFDebugInfoEntry.h" 11 #include "llvm/ADT/Optional.h" 12 #include "llvm/DebugInfo/DWARF/DWARFDebugAbbrev.h" 13 #include "llvm/DebugInfo/DWARF/DWARFFormValue.h" 14 #include "llvm/DebugInfo/DWARF/DWARFUnit.h" 15 #include "llvm/Support/DataExtractor.h" 16 #include <cstddef> 17 #include <cstdint> 18 19 using namespace llvm; 20 using namespace dwarf; 21 22 bool DWARFDebugInfoEntry::extractFast(const DWARFUnit &U, 23 uint32_t *OffsetPtr) { 24 DWARFDataExtractor DebugInfoData = U.getDebugInfoExtractor(); 25 const uint32_t UEndOffset = U.getNextUnitOffset(); 26 return extractFast(U, OffsetPtr, DebugInfoData, UEndOffset, 0); 27 } 28 29 bool DWARFDebugInfoEntry::extractFast(const DWARFUnit &U, uint32_t *OffsetPtr, 30 const DWARFDataExtractor &DebugInfoData, 31 uint32_t UEndOffset, uint32_t D) { 32 Offset = *OffsetPtr; 33 Depth = D; 34 if (Offset >= UEndOffset || !DebugInfoData.isValidOffset(Offset)) 35 return false; 36 uint64_t AbbrCode = DebugInfoData.getULEB128(OffsetPtr); 37 if (0 == AbbrCode) { 38 // NULL debug tag entry. 39 AbbrevDecl = nullptr; 40 return true; 41 } 42 AbbrevDecl = U.getAbbreviations()->getAbbreviationDeclaration(AbbrCode); 43 if (nullptr == AbbrevDecl) { 44 // Restore the original offset. 45 *OffsetPtr = Offset; 46 return false; 47 } 48 // See if all attributes in this DIE have fixed byte sizes. If so, we can 49 // just add this size to the offset to skip to the next DIE. 50 if (Optional<size_t> FixedSize = AbbrevDecl->getFixedAttributesByteSize(U)) { 51 *OffsetPtr += *FixedSize; 52 return true; 53 } 54 55 // Skip all data in the .debug_info for the attributes 56 for (const auto &AttrSpec : AbbrevDecl->attributes()) { 57 // Check if this attribute has a fixed byte size. 58 if (auto FixedSize = AttrSpec.getByteSize(U)) { 59 // Attribute byte size if fixed, just add the size to the offset. 60 *OffsetPtr += *FixedSize; 61 } else if (!DWARFFormValue::skipValue(AttrSpec.Form, DebugInfoData, 62 OffsetPtr, U.getFormParams())) { 63 // We failed to skip this attribute's value, restore the original offset 64 // and return the failure status. 65 *OffsetPtr = Offset; 66 return false; 67 } 68 } 69 return true; 70 } 71
