llvm/lib/DebugInfo/DWARF/DWARFDebugInfoEntry.cpp

   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/DWARFContext.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, uint64_t *OffsetPtr,
  23                                       const DWARFDataExtractor &DebugInfoData,
  24                                       uint64_t UEndOffset, uint32_t D) {
  25   Offset = *OffsetPtr;
  26   Depth = D;
  27   if (Offset >= UEndOffset) {
  28     U.getContext().getWarningHandler()(
  29         createStringError(errc::invalid_argument,
  30                           "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                           U.getOffset(), U.getNextUnitOffset(), *OffsetPtr));
  34     return false;
  35   }
  36   assert(DebugInfoData.isValidOffset(UEndOffset - 1));
  37   uint64_t AbbrCode = DebugInfoData.getULEB128(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(errc::invalid_argument,
  47                           "DWARF unit at offset 0x%8.8" PRIx64 " "
  48                           "contains invalid abbreviation set offset 0x%" PRIx64,
  49                           U.getOffset(), 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(errc::invalid_argument,
  58                           "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                           U.getOffset(), AbbrCode, *OffsetPtr,
  62                           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 (Optional<size_t> FixedSize = AbbrevDecl->getFixedAttributesByteSize(U)) {
  70     *OffsetPtr += *FixedSize;
  71     return true;
  72   }
  73
  74   // Skip all data in the .debug_info for the attributes
  75   for (const auto &AttrSpec : AbbrevDecl->attributes()) {
  76     // Check if this attribute has a fixed byte size.
  77     if (auto FixedSize = AttrSpec.getByteSize(U)) {
  78       // Attribute byte size if fixed, just add the size to the offset.
  79       *OffsetPtr += *FixedSize;
  80     } else if (!DWARFFormValue::skipValue(AttrSpec.Form, DebugInfoData,
  81                                           OffsetPtr, U.getFormParams())) {
  82       // We failed to skip this attribute's value, restore the original offset
  83       // and return the failure status.
  84       U.getContext().getWarningHandler()(createStringError(
  85           errc::invalid_argument,
  86           "DWARF unit at offset 0x%8.8" PRIx64 " "
  87           "contains invalid FORM_* 0x%" PRIx16 " at offset 0x%8.8" PRIx64,
  88           U.getOffset(), AttrSpec.Form, *OffsetPtr));
  89       *OffsetPtr = Offset;
  90       return false;
  91     }
  92   }
  93   return true;
  94 }