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
28 namespace llvm {
29
30 class LLVMContext;
31 class raw_ostream;
32
33 namespace object {
34
35 union 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
DataRefImpl()43 DataRefImpl() { std::memset(this, 0, sizeof(DataRefImpl)); }
44 };
45
46 template <typename OStream>
47 OStream& 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
53 inline 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
59 inline bool operator!=(const DataRefImpl &a, const DataRefImpl &b) {
60 return !operator==(a, b);
61 }
62
63 inline 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
69 template <class content_type> class content_iterator {
70 content_type Current;
71
72 public:
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
content_iterator(content_type symb)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
99 class SymbolicFile;
100
101 /// This is a value type class that represents a single symbol in the list of
102 /// symbols in the object file.
103 class BasicSymbolRef {
104 DataRefImpl SymbolPimpl;
105 const SymbolicFile *OwningObject = nullptr;
106
107 public:
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
143 using basic_symbol_iterator = content_iterator<BasicSymbolRef>;
144
145 class SymbolicFile : public Binary {
146 public:
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>;
symbols()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>>
createSymbolicFile(MemoryBufferRef Object)175 createSymbolicFile(MemoryBufferRef Object) {
176 return createSymbolicFile(Object, llvm::file_magic::unknown, nullptr);
177 }
178
classof(const Binary * v)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
BasicSymbolRef(DataRefImpl SymbolP,const SymbolicFile * Owner)186 inline BasicSymbolRef::BasicSymbolRef(DataRefImpl SymbolP,
187 const SymbolicFile *Owner)
188 : SymbolPimpl(SymbolP), OwningObject(Owner) {}
189
190 inline bool BasicSymbolRef::operator==(const BasicSymbolRef &Other) const {
191 return SymbolPimpl == Other.SymbolPimpl;
192 }
193
194 inline bool BasicSymbolRef::operator<(const BasicSymbolRef &Other) const {
195 return SymbolPimpl < Other.SymbolPimpl;
196 }
197
moveNext()198 inline void BasicSymbolRef::moveNext() {
199 return OwningObject->moveSymbolNext(SymbolPimpl);
200 }
201
printName(raw_ostream & OS)202 inline Error BasicSymbolRef::printName(raw_ostream &OS) const {
203 return OwningObject->printSymbolName(OS, SymbolPimpl);
204 }
205
getFlags()206 inline Expected<uint32_t> BasicSymbolRef::getFlags() const {
207 return OwningObject->getSymbolFlags(SymbolPimpl);
208 }
209
getRawDataRefImpl()210 inline DataRefImpl BasicSymbolRef::getRawDataRefImpl() const {
211 return SymbolPimpl;
212 }
213
getObject()214 inline 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