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