SymbolicFile.h revision d111c7844ec26448764ced627e153f406d730c5f
1//===- SymbolicFile.h - Interface that only provides symbols ----*- 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// This file declares the SymbolicFile interface.
10//
11//===----------------------------------------------------------------------===//
12
13#ifndef LLVM_OBJECT_SYMBOLICFILE_H
14#define LLVM_OBJECT_SYMBOLICFILE_H
15
16#include "llvm/ADT/StringRef.h"
17#include "llvm/ADT/iterator_range.h"
18#include "llvm/BinaryFormat/Magic.h"
19#include "llvm/Object/Binary.h"
20#include "llvm/Support/Error.h"
21#include "llvm/Support/FileSystem.h"
22#include "llvm/Support/Format.h"
23#include "llvm/Support/MemoryBuffer.h"
24#include <cinttypes>
25#include <cstdint>
26#include <cstring>
27#include <iterator>
28#include <memory>
29#include <system_error>
30
31namespace llvm {
32namespace object {
33
34union DataRefImpl {
35  // This entire union should probably be a
36  // char[max(8, sizeof(uintptr_t))] and require the impl to cast.
37  struct {
38    uint32_t a, b;
39  } d;
40  uintptr_t p;
41
42  DataRefImpl() { std::memset(this, 0, sizeof(DataRefImpl)); }
43};
44
45template <typename OStream>
46OStream& operator<<(OStream &OS, const DataRefImpl &D) {
47  OS << "(" << format("0x%08" PRIxPTR, D.p) << " (" << format("0x%08x", D.d.a)
48     << ", " << format("0x%08x", D.d.b) << "))";
49  return OS;
50}
51
52inline bool operator==(const DataRefImpl &a, const DataRefImpl &b) {
53  // Check bitwise identical. This is the only legal way to compare a union w/o
54  // knowing which member is in use.
55  return std::memcmp(&a, &b, sizeof(DataRefImpl)) == 0;
56}
57
58inline bool operator!=(const DataRefImpl &a, const DataRefImpl &b) {
59  return !operator==(a, b);
60}
61
62inline bool operator<(const DataRefImpl &a, const DataRefImpl &b) {
63  // Check bitwise identical. This is the only legal way to compare a union w/o
64  // knowing which member is in use.
65  return std::memcmp(&a, &b, sizeof(DataRefImpl)) < 0;
66}
67
68template <class content_type>
69class content_iterator
70    : public std::iterator<std::forward_iterator_tag, content_type> {
71  content_type Current;
72
73public:
74  content_iterator(content_type symb) : Current(std::move(symb)) {}
75
76  const content_type *operator->() const { return &Current; }
77
78  const content_type &operator*() const { return Current; }
79
80  bool operator==(const content_iterator &other) const {
81    return Current == other.Current;
82  }
83
84  bool operator!=(const content_iterator &other) const {
85    return !(*this == other);
86  }
87
88  content_iterator &operator++() { // preincrement
89    Current.moveNext();
90    return *this;
91  }
92};
93
94class SymbolicFile;
95
96/// This is a value type class that represents a single symbol in the list of
97/// symbols in the object file.
98class BasicSymbolRef {
99  DataRefImpl SymbolPimpl;
100  const SymbolicFile *OwningObject = nullptr;
101
102public:
103  enum Flags : unsigned {
104    SF_None = 0,
105    SF_Undefined = 1U << 0,      // Symbol is defined in another object file
106    SF_Global = 1U << 1,         // Global symbol
107    SF_Weak = 1U << 2,           // Weak symbol
108    SF_Absolute = 1U << 3,       // Absolute symbol
109    SF_Common = 1U << 4,         // Symbol has common linkage
110    SF_Indirect = 1U << 5,       // Symbol is an alias to another symbol
111    SF_Exported = 1U << 6,       // Symbol is visible to other DSOs
112    SF_FormatSpecific = 1U << 7, // Specific to the object file format
113                                 // (e.g. section symbols)
114    SF_Thumb = 1U << 8,          // Thumb symbol in a 32-bit ARM binary
115    SF_Hidden = 1U << 9,         // Symbol has hidden visibility
116    SF_Const = 1U << 10,         // Symbol value is constant
117    SF_Executable = 1U << 11,    // Symbol points to an executable section
118                                 // (IR only)
119  };
120
121  BasicSymbolRef() = default;
122  BasicSymbolRef(DataRefImpl SymbolP, const SymbolicFile *Owner);
123
124  bool operator==(const BasicSymbolRef &Other) const;
125  bool operator<(const BasicSymbolRef &Other) const;
126
127  void moveNext();
128
129  Error printName(raw_ostream &OS) const;
130
131  /// Get symbol flags (bitwise OR of SymbolRef::Flags)
132  uint32_t getFlags() const;
133
134  DataRefImpl getRawDataRefImpl() const;
135  const SymbolicFile *getObject() const;
136};
137
138using basic_symbol_iterator = content_iterator<BasicSymbolRef>;
139
140class SymbolicFile : public Binary {
141public:
142  SymbolicFile(unsigned int Type, MemoryBufferRef Source);
143  ~SymbolicFile() override;
144
145  // virtual interface.
146  virtual void moveSymbolNext(DataRefImpl &Symb) const = 0;
147
148  virtual Error printSymbolName(raw_ostream &OS, DataRefImpl Symb) const = 0;
149
150  virtual uint32_t getSymbolFlags(DataRefImpl Symb) const = 0;
151
152  virtual basic_symbol_iterator symbol_begin() const = 0;
153
154  virtual basic_symbol_iterator symbol_end() const = 0;
155
156  // convenience wrappers.
157  using basic_symbol_iterator_range = iterator_range<basic_symbol_iterator>;
158  basic_symbol_iterator_range symbols() const {
159    return basic_symbol_iterator_range(symbol_begin(), symbol_end());
160  }
161
162  // construction aux.
163  static Expected<std::unique_ptr<SymbolicFile>>
164  createSymbolicFile(MemoryBufferRef Object, llvm::file_magic Type,
165                     LLVMContext *Context);
166
167  static Expected<std::unique_ptr<SymbolicFile>>
168  createSymbolicFile(MemoryBufferRef Object) {
169    return createSymbolicFile(Object, llvm::file_magic::unknown, nullptr);
170  }
171  static Expected<OwningBinary<SymbolicFile>>
172  createSymbolicFile(StringRef ObjectPath);
173
174  static bool classof(const Binary *v) {
175    return v->isSymbolic();
176  }
177};
178
179inline BasicSymbolRef::BasicSymbolRef(DataRefImpl SymbolP,
180                                      const SymbolicFile *Owner)
181    : SymbolPimpl(SymbolP), OwningObject(Owner) {}
182
183inline bool BasicSymbolRef::operator==(const BasicSymbolRef &Other) const {
184  return SymbolPimpl == Other.SymbolPimpl;
185}
186
187inline bool BasicSymbolRef::operator<(const BasicSymbolRef &Other) const {
188  return SymbolPimpl < Other.SymbolPimpl;
189}
190
191inline void BasicSymbolRef::moveNext() {
192  return OwningObject->moveSymbolNext(SymbolPimpl);
193}
194
195inline Error BasicSymbolRef::printName(raw_ostream &OS) const {
196  return OwningObject->printSymbolName(OS, SymbolPimpl);
197}
198
199inline uint32_t BasicSymbolRef::getFlags() const {
200  return OwningObject->getSymbolFlags(SymbolPimpl);
201}
202
203inline DataRefImpl BasicSymbolRef::getRawDataRefImpl() const {
204  return SymbolPimpl;
205}
206
207inline const SymbolicFile *BasicSymbolRef::getObject() const {
208  return OwningObject;
209}
210
211} // end namespace object
212} // end namespace llvm
213
214#endif // LLVM_OBJECT_SYMBOLICFILE_H
215