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/iterator_range.h"
17#include "llvm/BinaryFormat/Magic.h"
18#include "llvm/Object/Binary.h"
19#include "llvm/Support/Error.h"
20#include "llvm/Support/Format.h"
21#include "llvm/Support/MemoryBufferRef.h"
22#include <cinttypes>
23#include <cstdint>
24#include <cstring>
25#include <iterator>
26#include <memory>
27
28namespace llvm {
29
30class LLVMContext;
31class raw_ostream;
32
33namespace object {
34
35union DataRefImpl {
36  // This entire union should probably be a
37  // char[max(8, sizeof(uintptr_t))] and require the impl to cast.
38  struct {
39    uint32_t a, b;
40  } d;
41  uintptr_t p;
42
43  DataRefImpl() { std::memset(this, 0, sizeof(DataRefImpl)); }
44};
45
46template <typename OStream>
47OStream& operator<<(OStream &OS, const DataRefImpl &D) {
48  OS << "(" << format("0x%08" PRIxPTR, D.p) << " (" << format("0x%08x", D.d.a)
49     << ", " << format("0x%08x", D.d.b) << "))";
50  return OS;
51}
52
53inline bool operator==(const DataRefImpl &a, const DataRefImpl &b) {
54  // Check bitwise identical. This is the only legal way to compare a union w/o
55  // knowing which member is in use.
56  return std::memcmp(&a, &b, sizeof(DataRefImpl)) == 0;
57}
58
59inline bool operator!=(const DataRefImpl &a, const DataRefImpl &b) {
60  return !operator==(a, b);
61}
62
63inline bool operator<(const DataRefImpl &a, const DataRefImpl &b) {
64  // Check bitwise identical. This is the only legal way to compare a union w/o
65  // knowing which member is in use.
66  return std::memcmp(&a, &b, sizeof(DataRefImpl)) < 0;
67}
68
69template <class content_type> class content_iterator {
70  content_type Current;
71
72public:
73  using iterator_category = std::forward_iterator_tag;
74  using value_type = content_type;
75  using difference_type = std::ptrdiff_t;
76  using pointer = value_type *;
77  using reference = value_type &;
78
79  content_iterator(content_type symb) : Current(std::move(symb)) {}
80
81  const content_type *operator->() const { return &Current; }
82
83  const content_type &operator*() const { return Current; }
84
85  bool operator==(const content_iterator &other) const {
86    return Current == other.Current;
87  }
88
89  bool operator!=(const content_iterator &other) const {
90    return !(*this == other);
91  }
92
93  content_iterator &operator++() { // preincrement
94    Current.moveNext();
95    return *this;
96  }
97};
98
99class SymbolicFile;
100
101/// This is a value type class that represents a single symbol in the list of
102/// symbols in the object file.
103class BasicSymbolRef {
104  DataRefImpl SymbolPimpl;
105  const SymbolicFile *OwningObject = nullptr;
106
107public:
108  enum Flags : unsigned {
109    SF_None = 0,
110    SF_Undefined = 1U << 0,      // Symbol is defined in another object file
111    SF_Global = 1U << 1,         // Global symbol
112    SF_Weak = 1U << 2,           // Weak symbol
113    SF_Absolute = 1U << 3,       // Absolute symbol
114    SF_Common = 1U << 4,         // Symbol has common linkage
115    SF_Indirect = 1U << 5,       // Symbol is an alias to another symbol
116    SF_Exported = 1U << 6,       // Symbol is visible to other DSOs
117    SF_FormatSpecific = 1U << 7, // Specific to the object file format
118                                 // (e.g. section symbols)
119    SF_Thumb = 1U << 8,          // Thumb symbol in a 32-bit ARM binary
120    SF_Hidden = 1U << 9,         // Symbol has hidden visibility
121    SF_Const = 1U << 10,         // Symbol value is constant
122    SF_Executable = 1U << 11,    // Symbol points to an executable section
123                                 // (IR only)
124  };
125
126  BasicSymbolRef() = default;
127  BasicSymbolRef(DataRefImpl SymbolP, const SymbolicFile *Owner);
128
129  bool operator==(const BasicSymbolRef &Other) const;
130  bool operator<(const BasicSymbolRef &Other) const;
131
132  void moveNext();
133
134  Error printName(raw_ostream &OS) const;
135
136  /// Get symbol flags (bitwise OR of SymbolRef::Flags)
137  Expected<uint32_t> getFlags() const;
138
139  DataRefImpl getRawDataRefImpl() const;
140  const SymbolicFile *getObject() const;
141};
142
143using basic_symbol_iterator = content_iterator<BasicSymbolRef>;
144
145class SymbolicFile : public Binary {
146public:
147  SymbolicFile(unsigned int Type, MemoryBufferRef Source);
148  ~SymbolicFile() override;
149
150  // virtual interface.
151  virtual void moveSymbolNext(DataRefImpl &Symb) const = 0;
152
153  virtual Error printSymbolName(raw_ostream &OS, DataRefImpl Symb) const = 0;
154
155  virtual Expected<uint32_t> getSymbolFlags(DataRefImpl Symb) const = 0;
156
157  virtual basic_symbol_iterator symbol_begin() const = 0;
158
159  virtual basic_symbol_iterator symbol_end() const = 0;
160
161  virtual bool is64Bit() const = 0;
162
163  // convenience wrappers.
164  using basic_symbol_iterator_range = iterator_range<basic_symbol_iterator>;
165  basic_symbol_iterator_range symbols() const {
166    return basic_symbol_iterator_range(symbol_begin(), symbol_end());
167  }
168
169  // construction aux.
170  static Expected<std::unique_ptr<SymbolicFile>>
171  createSymbolicFile(MemoryBufferRef Object, llvm::file_magic Type,
172                     LLVMContext *Context, bool InitContent = true);
173
174  static Expected<std::unique_ptr<SymbolicFile>>
175  createSymbolicFile(MemoryBufferRef Object) {
176    return createSymbolicFile(Object, llvm::file_magic::unknown, nullptr);
177  }
178
179  static bool classof(const Binary *v) {
180    return v->isSymbolic();
181  }
182
183  static bool isSymbolicFile(file_magic Type, const LLVMContext *Context);
184};
185
186inline BasicSymbolRef::BasicSymbolRef(DataRefImpl SymbolP,
187                                      const SymbolicFile *Owner)
188    : SymbolPimpl(SymbolP), OwningObject(Owner) {}
189
190inline bool BasicSymbolRef::operator==(const BasicSymbolRef &Other) const {
191  return SymbolPimpl == Other.SymbolPimpl;
192}
193
194inline bool BasicSymbolRef::operator<(const BasicSymbolRef &Other) const {
195  return SymbolPimpl < Other.SymbolPimpl;
196}
197
198inline void BasicSymbolRef::moveNext() {
199  return OwningObject->moveSymbolNext(SymbolPimpl);
200}
201
202inline Error BasicSymbolRef::printName(raw_ostream &OS) const {
203  return OwningObject->printSymbolName(OS, SymbolPimpl);
204}
205
206inline Expected<uint32_t> BasicSymbolRef::getFlags() const {
207  return OwningObject->getSymbolFlags(SymbolPimpl);
208}
209
210inline DataRefImpl BasicSymbolRef::getRawDataRefImpl() const {
211  return SymbolPimpl;
212}
213
214inline const SymbolicFile *BasicSymbolRef::getObject() const {
215  return OwningObject;
216}
217
218} // end namespace object
219} // end namespace llvm
220
221#endif // LLVM_OBJECT_SYMBOLICFILE_H
222