1 //===- DWARFDebugInfoEntry.cpp --------------------------------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #include "llvm/DebugInfo/DWARF/DWARFDebugInfoEntry.h" 10 #include "llvm/ADT/Optional.h" 11 #include "llvm/DebugInfo/DWARF/DWARFDebugAbbrev.h" 12 #include "llvm/DebugInfo/DWARF/DWARFFormValue.h" 13 #include "llvm/DebugInfo/DWARF/DWARFUnit.h" 14 #include "llvm/Support/DataExtractor.h" 15 #include <cstddef> 16 #include <cstdint> 17 18 using namespace llvm; 19 using namespace dwarf; 20 21 bool DWARFDebugInfoEntry::extractFast(const DWARFUnit &U, 22 uint64_t *OffsetPtr) { 23 DWARFDataExtractor DebugInfoData = U.getDebugInfoExtractor(); 24 const uint64_t UEndOffset = U.getNextUnitOffset(); 25 return extractFast(U, OffsetPtr, DebugInfoData, UEndOffset, 0); 26 } 27 28 bool DWARFDebugInfoEntry::extractFast(const DWARFUnit &U, uint64_t *OffsetPtr, 29 const DWARFDataExtractor &DebugInfoData, 30 uint64_t UEndOffset, uint32_t D) { 31 Offset = *OffsetPtr; 32 Depth = D; 33 if (Offset >= UEndOffset || !DebugInfoData.isValidOffset(Offset)) 34 return false; 35 uint64_t AbbrCode = DebugInfoData.getULEB128(OffsetPtr); 36 if (0 == AbbrCode) { 37 // NULL debug tag entry. 38 AbbrevDecl = nullptr; 39 return true; 40 } 41 AbbrevDecl = U.getAbbreviations()->getAbbreviationDeclaration(AbbrCode); 42 if (nullptr == AbbrevDecl) { 43 // Restore the original offset. 44 *OffsetPtr = Offset; 45 return false; 46 } 47 // See if all attributes in this DIE have fixed byte sizes. If so, we can 48 // just add this size to the offset to skip to the next DIE. 49 if (Optional<size_t> FixedSize = AbbrevDecl->getFixedAttributesByteSize(U)) { 50 *OffsetPtr += *FixedSize; 51 return true; 52 } 53 54 // Skip all data in the .debug_info for the attributes 55 for (const auto &AttrSpec : AbbrevDecl->attributes()) { 56 // Check if this attribute has a fixed byte size. 57 if (auto FixedSize = AttrSpec.getByteSize(U)) { 58 // Attribute byte size if fixed, just add the size to the offset. 59 *OffsetPtr += *FixedSize; 60 } else if (!DWARFFormValue::skipValue(AttrSpec.Form, DebugInfoData, 61 OffsetPtr, U.getFormParams())) { 62 // We failed to skip this attribute's value, restore the original offset 63 // and return the failure status. 64 *OffsetPtr = Offset; 65 return false; 66 } 67 } 68 return true; 69 } 70