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//===- DWARFDebugInfoEntry.cpp --------------------------------------------===//
//
// 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/DWARFDebugInfoEntry.h"
#include "llvm/ADT/Optional.h"
#include "llvm/DebugInfo/DWARF/DWARFDebugAbbrev.h"
#include "llvm/DebugInfo/DWARF/DWARFFormValue.h"
#include "llvm/DebugInfo/DWARF/DWARFUnit.h"
#include "llvm/Support/DataExtractor.h"
#include <cstddef>
#include <cstdint>
using namespace llvm;
using namespace dwarf;
bool DWARFDebugInfoEntry::extractFast(const DWARFUnit &U,
uint64_t *OffsetPtr) {
DWARFDataExtractor DebugInfoData = U.getDebugInfoExtractor();
const uint64_t UEndOffset = U.getNextUnitOffset();
return extractFast(U, OffsetPtr, DebugInfoData, UEndOffset, 0);
}
bool DWARFDebugInfoEntry::extractFast(const DWARFUnit &U, uint64_t *OffsetPtr,
const DWARFDataExtractor &DebugInfoData,
uint64_t UEndOffset, uint32_t D) {
Offset = *OffsetPtr;
Depth = D;
if (Offset >= UEndOffset || !DebugInfoData.isValidOffset(Offset))
return false;
uint64_t AbbrCode = DebugInfoData.getULEB128(OffsetPtr);
if (0 == AbbrCode) {
// NULL debug tag entry.
AbbrevDecl = nullptr;
return true;
}
if (const auto *AbbrevSet = U.getAbbreviations())
AbbrevDecl = AbbrevSet->getAbbreviationDeclaration(AbbrCode);
if (nullptr == AbbrevDecl) {
// Restore the original offset.
*OffsetPtr = Offset;
return false;
}
// See if all attributes in this DIE have fixed byte sizes. If so, we can
// just add this size to the offset to skip to the next DIE.
if (Optional<size_t> FixedSize = AbbrevDecl->getFixedAttributesByteSize(U)) {
*OffsetPtr += *FixedSize;
return true;
}
// Skip all data in the .debug_info for the attributes
for (const auto &AttrSpec : AbbrevDecl->attributes()) {
// Check if this attribute has a fixed byte size.
if (auto FixedSize = AttrSpec.getByteSize(U)) {
// Attribute byte size if fixed, just add the size to the offset.
*OffsetPtr += *FixedSize;
} else if (!DWARFFormValue::skipValue(AttrSpec.Form, DebugInfoData,
OffsetPtr, U.getFormParams())) {
// We failed to skip this attribute's value, restore the original offset
// and return the failure status.
*OffsetPtr = Offset;
return false;
}
}
return true;
}
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