DWARFFormValue.h revision 6948897e478cbd66626159776a8017b3c18579b9 
1//===-- DWARFFormValue.h ----------------------------------------*- C++ -*-===//
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
10#ifndef LLVM_DEBUGINFO_DWARFFORMVALUE_H
11#define LLVM_DEBUGINFO_DWARFFORMVALUE_H
12
13#include "llvm/ADT/ArrayRef.h"
14#include "llvm/ADT/Optional.h"
15#include "llvm/Support/DataExtractor.h"
16
17namespace llvm {
18
19class DWARFUnit;
20class raw_ostream;
21
22class DWARFFormValue {
23public:
24  enum FormClass {
25    FC_Unknown,
26    FC_Address,
27    FC_Block,
28    FC_Constant,
29    FC_String,
30    FC_Flag,
31    FC_Reference,
32    FC_Indirect,
33    FC_SectionOffset,
34    FC_Exprloc
35  };
36
37private:
38  struct ValueType {
39    ValueType() : data(nullptr) {
40      uval = 0;
41    }
42
43    union {
44      uint64_t uval;
45      int64_t sval;
46      const char* cstr;
47    };
48    const uint8_t* data;
49  };
50
51  uint16_t Form;   // Form for this value.
52  ValueType Value; // Contains all data for the form.
53
54public:
55  DWARFFormValue(uint16_t Form = 0) : Form(Form) {}
56  uint16_t getForm() const { return Form; }
57  bool isFormClass(FormClass FC) const;
58
59  void dump(raw_ostream &OS, const DWARFUnit *U) const;
60
61  /// \brief extracts a value in data at offset *offset_ptr.
62  ///
63  /// The passed DWARFUnit is allowed to be nullptr, in which
64  /// case no relocation processing will be performed and some
65  /// kind of forms that depend on Unit information are disallowed.
66  /// \returns whether the extraction succeeded.
67  bool extractValue(DataExtractor data, uint32_t *offset_ptr,
68                    const DWARFUnit *u);
69  bool isInlinedCStr() const {
70    return Value.data != nullptr && Value.data == (const uint8_t*)Value.cstr;
71  }
72
73  /// getAsFoo functions below return the extracted value as Foo if only
74  /// DWARFFormValue has form class is suitable for representing Foo.
75  Optional<uint64_t> getAsReference(const DWARFUnit *U) const;
76  Optional<uint64_t> getAsUnsignedConstant() const;
77  Optional<int64_t> getAsSignedConstant() const;
78  Optional<const char *> getAsCString(const DWARFUnit *U) const;
79  Optional<uint64_t> getAsAddress(const DWARFUnit *U) const;
80  Optional<uint64_t> getAsSectionOffset() const;
81  Optional<ArrayRef<uint8_t>> getAsBlock() const;
82
83  bool skipValue(DataExtractor debug_info_data, uint32_t *offset_ptr,
84                 const DWARFUnit *u) const;
85  static bool skipValue(uint16_t form, DataExtractor debug_info_data,
86                        uint32_t *offset_ptr, const DWARFUnit *u);
87
88  static ArrayRef<uint8_t> getFixedFormSizes(uint8_t AddrSize,
89                                             uint16_t Version);
90private:
91  void dumpString(raw_ostream &OS, const DWARFUnit *U) const;
92};
93
94}
95
96#endif
97