DWARFDataExtractor.h revision 360784 
1//===- DWARFDataExtractor.h -------------------------------------*- C++ -*-===//
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#ifndef LLVM_DEBUGINFO_DWARFDATAEXTRACTOR_H
10#define LLVM_DEBUGINFO_DWARFDATAEXTRACTOR_H
11
12#include "llvm/DebugInfo/DWARF/DWARFSection.h"
13#include "llvm/Support/DataExtractor.h"
14
15namespace llvm {
16class DWARFObject;
17
18/// A DataExtractor (typically for an in-memory copy of an object-file section)
19/// plus a relocation map for that section, if there is one.
20class DWARFDataExtractor : public DataExtractor {
21  const DWARFObject *Obj = nullptr;
22  const DWARFSection *Section = nullptr;
23
24public:
25  /// Constructor for the normal case of extracting data from a DWARF section.
26  /// The DWARFSection's lifetime must be at least as long as the extractor's.
27  DWARFDataExtractor(const DWARFObject &Obj, const DWARFSection &Section,
28                     bool IsLittleEndian, uint8_t AddressSize)
29      : DataExtractor(Section.Data, IsLittleEndian, AddressSize), Obj(&Obj),
30        Section(&Section) {}
31
32  /// Constructor for cases when there are no relocations.
33  DWARFDataExtractor(StringRef Data, bool IsLittleEndian, uint8_t AddressSize)
34    : DataExtractor(Data, IsLittleEndian, AddressSize) {}
35
36  /// Extracts a value and applies a relocation to the result if
37  /// one exists for the given offset.
38  uint64_t getRelocatedValue(uint32_t Size, uint64_t *Off,
39                             uint64_t *SectionIndex = nullptr,
40                             Error *Err = nullptr) const;
41
42  /// Extracts an address-sized value and applies a relocation to the result if
43  /// one exists for the given offset.
44  uint64_t getRelocatedAddress(uint64_t *Off, uint64_t *SecIx = nullptr) const {
45    return getRelocatedValue(getAddressSize(), Off, SecIx);
46  }
47  uint64_t getRelocatedAddress(Cursor &C, uint64_t *SecIx = nullptr) const {
48    return getRelocatedValue(getAddressSize(), &getOffset(C), SecIx,
49                             &getError(C));
50  }
51
52  /// Extracts a DWARF-encoded pointer in \p Offset using \p Encoding.
53  /// There is a DWARF encoding that uses a PC-relative adjustment.
54  /// For these values, \p AbsPosOffset is used to fix them, which should
55  /// reflect the absolute address of this pointer.
56  Optional<uint64_t> getEncodedPointer(uint64_t *Offset, uint8_t Encoding,
57                                       uint64_t AbsPosOffset = 0) const;
58};
59
60} // end namespace llvm
61
62#endif // LLVM_DEBUGINFO_DWARFDATAEXTRACTOR_H
63