LLVM  6.0.0svn
DWARFDebugInfoEntry.cpp
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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 
11 #include "llvm/ADT/Optional.h"
16 #include <cstddef>
17 #include <cstdint>
18 
19 using namespace llvm;
20 using namespace dwarf;
21 
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 
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 }
const DWARFAbbreviationDeclarationSet * getAbbreviations() const
Definition: DWARFUnit.cpp:464
uint64_t getULEB128(uint32_t *offset_ptr) const
Extract a unsigned LEB128 value from *offset_ptr.
Compute iterated dominance frontiers using a linear time algorithm.
Definition: AllocatorList.h:24
const DWARFFormParams & getFormParams() const
Definition: DWARFUnit.h:275
uint32_t getNextUnitOffset() const
Definition: DWARFUnit.h:272
bool skipValue(DataExtractor DebugInfoData, uint32_t *OffsetPtr, const DWARFFormParams Params) const
Skip a form&#39;s value in DebugInfoData at the offset specified by OffsetPtr.
const DWARFAbbreviationDeclaration * getAbbreviationDeclaration(uint32_t AbbrCode) const
bool extractFast(const DWARFUnit &U, uint32_t *OffsetPtr)
Extracts a debug info entry, which is a child of a given unit, starting at a given offset...
A DataExtractor (typically for an in-memory copy of an object-file section) plus a relocation map for...
static GCRegistry::Add< StatepointGC > D("statepoint-example", "an example strategy for statepoint")
DWARFDataExtractor getDebugInfoExtractor() const
Definition: DWARFUnit.cpp:64
bool isValidOffset(uint32_t offset) const
Test the validity of offset.