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/DebugInfo/DWARF/DWARFContext.h"
11#include "llvm/DebugInfo/DWARF/DWARFDataExtractor.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/Errc.h"
16#include <cstddef>
17#include <cstdint>
18
19using namespace llvm;
20using namespace dwarf;
21
22bool DWARFDebugInfoEntry::extractFast(const DWARFUnit &U, uint64_t *OffsetPtr,
23 const DWARFDataExtractor &DebugInfoData,
24 uint64_t UEndOffset, uint32_t ParentIdx) {
25 Offset = *OffsetPtr;
26 this->ParentIdx = ParentIdx;
27 if (Offset >= UEndOffset) {
28 U.getContext().getWarningHandler()(
29 createStringError(EC: errc::invalid_argument,
30 Fmt: "DWARF unit from offset 0x%8.8" PRIx64 " incl. "
31 "to offset 0x%8.8" PRIx64 " excl. "
32 "tries to read DIEs at offset 0x%8.8" PRIx64,
33 Vals: U.getOffset(), Vals: U.getNextUnitOffset(), Vals: *OffsetPtr));
34 return false;
35 }
36 assert(DebugInfoData.isValidOffset(UEndOffset - 1));
37 uint64_t AbbrCode = DebugInfoData.getULEB128(offset_ptr: OffsetPtr);
38 if (0 == AbbrCode) {
39 // NULL debug tag entry.
40 AbbrevDecl = nullptr;
41 return true;
42 }
43 const auto *AbbrevSet = U.getAbbreviations();
44 if (!AbbrevSet) {
45 U.getContext().getWarningHandler()(
46 createStringError(EC: errc::invalid_argument,
47 Fmt: "DWARF unit at offset 0x%8.8" PRIx64 " "
48 "contains invalid abbreviation set offset 0x%" PRIx64,
49 Vals: U.getOffset(), Vals: U.getAbbreviationsOffset()));
50 // Restore the original offset.
51 *OffsetPtr = Offset;
52 return false;
53 }
54 AbbrevDecl = AbbrevSet->getAbbreviationDeclaration(AbbrCode);
55 if (!AbbrevDecl) {
56 U.getContext().getWarningHandler()(
57 createStringError(EC: errc::invalid_argument,
58 Fmt: "DWARF unit at offset 0x%8.8" PRIx64 " "
59 "contains invalid abbreviation %" PRIu64 " at "
60 "offset 0x%8.8" PRIx64 ", valid abbreviations are %s",
61 Vals: U.getOffset(), Vals: AbbrCode, Vals: *OffsetPtr,
62 Vals: AbbrevSet->getCodeRange().c_str()));
63 // Restore the original offset.
64 *OffsetPtr = Offset;
65 return false;
66 }
67 // See if all attributes in this DIE have fixed byte sizes. If so, we can
68 // just add this size to the offset to skip to the next DIE.
69 if (std::optional<size_t> FixedSize =
70 AbbrevDecl->getFixedAttributesByteSize(U)) {
71 *OffsetPtr += *FixedSize;
72 return true;
73 }
74
75 // Skip all data in the .debug_info for the attributes
76 for (const auto &AttrSpec : AbbrevDecl->attributes()) {
77 // Check if this attribute has a fixed byte size.
78 if (auto FixedSize = AttrSpec.getByteSize(U)) {
79 // Attribute byte size if fixed, just add the size to the offset.
80 *OffsetPtr += *FixedSize;
81 } else if (!DWARFFormValue::skipValue(Form: AttrSpec.Form, DebugInfoData,
82 OffsetPtr, FormParams: U.getFormParams())) {
83 // We failed to skip this attribute's value, restore the original offset
84 // and return the failure status.
85 U.getContext().getWarningHandler()(createStringError(
86 EC: errc::invalid_argument,
87 Fmt: "DWARF unit at offset 0x%8.8" PRIx64 " "
88 "contains invalid FORM_* 0x%" PRIx16 " at offset 0x%8.8" PRIx64,
89 Vals: U.getOffset(), Vals: AttrSpec.Form, Vals: *OffsetPtr));
90 *OffsetPtr = Offset;
91 return false;
92 }
93 }
94 return true;
95}
96