1//===- SymbolicFile.h - Interface that only provides symbols ----*- 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// This file declares the SymbolicFile interface.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef LLVM_OBJECT_SYMBOLICFILE_H
15#define LLVM_OBJECT_SYMBOLICFILE_H
16
17#include "llvm/ADT/StringRef.h"
18#include "llvm/ADT/iterator_range.h"
19#include "llvm/BinaryFormat/Magic.h"
20#include "llvm/Object/Binary.h"
21#include "llvm/Support/Error.h"
22#include "llvm/Support/FileSystem.h"
23#include "llvm/Support/Format.h"
24#include "llvm/Support/MemoryBuffer.h"
25#include <cinttypes>
26#include <cstdint>
27#include <cstring>
28#include <iterator>
29#include <memory>
30#include <system_error>
31
32namespace llvm {
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>
70class content_iterator
71    : public std::iterator<std::forward_iterator_tag, content_type> {
72  content_type Current;
73
74public:
75  content_iterator(content_type symb) : Current(std::move(symb)) {}
76
77  const content_type *operator->() const { return &Current; }
78
79  const content_type &operator*() const { return Current; }
80
81  bool operator==(const content_iterator &other) const {
82    return Current == other.Current;
83  }
84
85  bool operator!=(const content_iterator &other) const {
86    return !(*this == other);
87  }
88
89  content_iterator &operator++() { // preincrement
90    Current.moveNext();
91    return *this;
92  }
93};
94
95class SymbolicFile;
96
97/// This is a value type class that represents a single symbol in the list of
98/// symbols in the object file.
99class BasicSymbolRef {
100  DataRefImpl SymbolPimpl;
101  const SymbolicFile *OwningObject = nullptr;
102
103public:
104  enum Flags : unsigned {
105    SF_None = 0,
106    SF_Undefined = 1U << 0,      // Symbol is defined in another object file
107    SF_Global = 1U << 1,         // Global symbol
108    SF_Weak = 1U << 2,           // Weak symbol
109    SF_Absolute = 1U << 3,       // Absolute symbol
110    SF_Common = 1U << 4,         // Symbol has common linkage
111    SF_Indirect = 1U << 5,       // Symbol is an alias to another symbol
112    SF_Exported = 1U << 6,       // Symbol is visible to other DSOs
113    SF_FormatSpecific = 1U << 7, // Specific to the object file format
114                                 // (e.g. section symbols)
115    SF_Thumb = 1U << 8,          // Thumb symbol in a 32-bit ARM binary
116    SF_Hidden = 1U << 9,         // Symbol has hidden visibility
117    SF_Const = 1U << 10,         // Symbol value is constant
118    SF_Executable = 1U << 11,    // Symbol points to an executable section
119                                 // (IR only)
120  };
121
122  BasicSymbolRef() = default;
123  BasicSymbolRef(DataRefImpl SymbolP, const SymbolicFile *Owner);
124
125  bool operator==(const BasicSymbolRef &Other) const;
126  bool operator<(const BasicSymbolRef &Other) const;
127
128  void moveNext();
129
130  std::error_code printName(raw_ostream &OS) const;
131
132  /// Get symbol flags (bitwise OR of SymbolRef::Flags)
133  uint32_t getFlags() const;
134
135  DataRefImpl getRawDataRefImpl() const;
136  const SymbolicFile *getObject() const;
137};
138
139using basic_symbol_iterator = content_iterator<BasicSymbolRef>;
140
141class SymbolicFile : public Binary {
142public:
143  SymbolicFile(unsigned int Type, MemoryBufferRef Source);
144  ~SymbolicFile() override;
145
146  // virtual interface.
147  virtual void moveSymbolNext(DataRefImpl &Symb) const = 0;
148
149  virtual std::error_code printSymbolName(raw_ostream &OS,
150                                          DataRefImpl Symb) const = 0;
151
152  virtual uint32_t getSymbolFlags(DataRefImpl Symb) const = 0;
153
154  virtual basic_symbol_iterator symbol_begin() const = 0;
155
156  virtual basic_symbol_iterator symbol_end() const = 0;
157
158  // convenience wrappers.
159  using basic_symbol_iterator_range = iterator_range<basic_symbol_iterator>;
160  basic_symbol_iterator_range symbols() const {
161    return basic_symbol_iterator_range(symbol_begin(), symbol_end());
162  }
163
164  // construction aux.
165  static Expected<std::unique_ptr<SymbolicFile>>
166  createSymbolicFile(MemoryBufferRef Object, llvm::file_magic Type,
167                     LLVMContext *Context);
168
169  static Expected<std::unique_ptr<SymbolicFile>>
170  createSymbolicFile(MemoryBufferRef Object) {
171    return createSymbolicFile(Object, llvm::file_magic::unknown, nullptr);
172  }
173  static Expected<OwningBinary<SymbolicFile>>
174  createSymbolicFile(StringRef ObjectPath);
175
176  static bool classof(const Binary *v) {
177    return v->isSymbolic();
178  }
179};
180
181inline BasicSymbolRef::BasicSymbolRef(DataRefImpl SymbolP,
182                                      const SymbolicFile *Owner)
183    : SymbolPimpl(SymbolP), OwningObject(Owner) {}
184
185inline bool BasicSymbolRef::operator==(const BasicSymbolRef &Other) const {
186  return SymbolPimpl == Other.SymbolPimpl;
187}
188
189inline bool BasicSymbolRef::operator<(const BasicSymbolRef &Other) const {
190  return SymbolPimpl < Other.SymbolPimpl;
191}
192
193inline void BasicSymbolRef::moveNext() {
194  return OwningObject->moveSymbolNext(SymbolPimpl);
195}
196
197inline std::error_code BasicSymbolRef::printName(raw_ostream &OS) const {
198  return OwningObject->printSymbolName(OS, SymbolPimpl);
199}
200
201inline uint32_t BasicSymbolRef::getFlags() const {
202  return OwningObject->getSymbolFlags(SymbolPimpl);
203}
204
205inline DataRefImpl BasicSymbolRef::getRawDataRefImpl() const {
206  return SymbolPimpl;
207}
208
209inline const SymbolicFile *BasicSymbolRef::getObject() const {
210  return OwningObject;
211}
212
213} // end namespace object
214} // end namespace llvm
215
216#endif // LLVM_OBJECT_SYMBOLICFILE_H
217