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/Compiler.h"
20 #include "llvm/Support/Error.h"
21 #include "llvm/Support/Format.h"
22 #include "llvm/Support/MemoryBufferRef.h"
23 #include <cinttypes>
24 #include <cstdint>
25 #include <cstring>
26 #include <iterator>
27 #include <memory>
28
29 namespace llvm {
30
31 class LLVMContext;
32 class raw_ostream;
33
34 namespace object {
35
36 union DataRefImpl {
37 // This entire union should probably be a
38 // char[max(8, sizeof(uintptr_t))] and require the impl to cast.
39 struct {
40 uint32_t a, b;
41 } d;
42 uintptr_t p;
43
DataRefImpl()44 DataRefImpl() { std::memset(this, 0, sizeof(DataRefImpl)); }
45 };
46
47 template <typename OStream>
48 OStream& operator<<(OStream &OS, const DataRefImpl &D) {
49 OS << "(" << format("0x%08" PRIxPTR, D.p) << " (" << format("0x%08x", D.d.a)
50 << ", " << format("0x%08x", D.d.b) << "))";
51 return OS;
52 }
53
54 inline bool operator==(const DataRefImpl &a, const DataRefImpl &b) {
55 // Check bitwise identical. This is the only legal way to compare a union w/o
56 // knowing which member is in use.
57 return std::memcmp(&a, &b, sizeof(DataRefImpl)) == 0;
58 }
59
60 inline bool operator!=(const DataRefImpl &a, const DataRefImpl &b) {
61 return !operator==(a, b);
62 }
63
64 inline bool operator<(const DataRefImpl &a, const DataRefImpl &b) {
65 // Check bitwise identical. This is the only legal way to compare a union w/o
66 // knowing which member is in use.
67 return std::memcmp(&a, &b, sizeof(DataRefImpl)) < 0;
68 }
69
70 template <class content_type> class content_iterator {
71 content_type Current;
72
73 public:
74 using iterator_category = std::forward_iterator_tag;
75 using value_type = const content_type;
76 using difference_type = std::ptrdiff_t;
77 using pointer = value_type *;
78 using reference = value_type &;
79
content_iterator(content_type symb)80 content_iterator(content_type symb) : Current(std::move(symb)) {}
81
82 const content_type *operator->() const { return &Current; }
83
84 const content_type &operator*() const { return Current; }
85
86 bool operator==(const content_iterator &other) const {
87 return Current == other.Current;
88 }
89
90 bool operator!=(const content_iterator &other) const {
91 return !(*this == other);
92 }
93
94 content_iterator &operator++() { // preincrement
95 Current.moveNext();
96 return *this;
97 }
98 };
99
100 class SymbolicFile;
101
102 /// This is a value type class that represents a single symbol in the list of
103 /// symbols in the object file.
104 class BasicSymbolRef {
105 DataRefImpl SymbolPimpl;
106 const SymbolicFile *OwningObject = nullptr;
107
108 public:
109 enum Flags : unsigned {
110 SF_None = 0,
111 SF_Undefined = 1U << 0, // Symbol is defined in another object file
112 SF_Global = 1U << 1, // Global symbol
113 SF_Weak = 1U << 2, // Weak symbol
114 SF_Absolute = 1U << 3, // Absolute symbol
115 SF_Common = 1U << 4, // Symbol has common linkage
116 SF_Indirect = 1U << 5, // Symbol is an alias to another symbol
117 SF_Exported = 1U << 6, // Symbol is visible to other DSOs
118 SF_FormatSpecific = 1U << 7, // Specific to the object file format
119 // (e.g. section symbols)
120 SF_Thumb = 1U << 8, // Thumb symbol in a 32-bit ARM binary
121 SF_Hidden = 1U << 9, // Symbol has hidden visibility
122 SF_Const = 1U << 10, // Symbol value is constant
123 SF_Executable = 1U << 11, // Symbol points to an executable section
124 // (IR only)
125 };
126
127 BasicSymbolRef() = default;
128 BasicSymbolRef(DataRefImpl SymbolP, const SymbolicFile *Owner);
129
130 bool operator==(const BasicSymbolRef &Other) const;
131 bool operator<(const BasicSymbolRef &Other) const;
132
133 void moveNext();
134
135 Error printName(raw_ostream &OS) const;
136
137 /// Get symbol flags (bitwise OR of SymbolRef::Flags)
138 Expected<uint32_t> getFlags() const;
139
140 DataRefImpl getRawDataRefImpl() const;
141 const SymbolicFile *getObject() const;
142 };
143
144 using basic_symbol_iterator = content_iterator<BasicSymbolRef>;
145
146 class LLVM_ABI SymbolicFile : public Binary {
147 public:
148 SymbolicFile(unsigned int Type, MemoryBufferRef Source);
149 ~SymbolicFile() override;
150
151 // virtual interface.
152 virtual void moveSymbolNext(DataRefImpl &Symb) const = 0;
153
154 virtual Error printSymbolName(raw_ostream &OS, DataRefImpl Symb) const = 0;
155
156 virtual Expected<uint32_t> getSymbolFlags(DataRefImpl Symb) const = 0;
157
158 virtual basic_symbol_iterator symbol_begin() const = 0;
159
160 virtual basic_symbol_iterator symbol_end() const = 0;
161
162 virtual bool is64Bit() const = 0;
163
164 // convenience wrappers.
165 using basic_symbol_iterator_range = iterator_range<basic_symbol_iterator>;
symbols()166 basic_symbol_iterator_range symbols() const {
167 return basic_symbol_iterator_range(symbol_begin(), symbol_end());
168 }
169
170 // construction aux.
171 static Expected<std::unique_ptr<SymbolicFile>>
172 createSymbolicFile(MemoryBufferRef Object, llvm::file_magic Type,
173 LLVMContext *Context, bool InitContent = true);
174
175 static Expected<std::unique_ptr<SymbolicFile>>
createSymbolicFile(MemoryBufferRef Object)176 createSymbolicFile(MemoryBufferRef Object) {
177 return createSymbolicFile(Object, llvm::file_magic::unknown, nullptr);
178 }
179
classof(const Binary * v)180 static bool classof(const Binary *v) {
181 return v->isSymbolic();
182 }
183
184 static bool isSymbolicFile(file_magic Type, const LLVMContext *Context);
185 };
186
BasicSymbolRef(DataRefImpl SymbolP,const SymbolicFile * Owner)187 inline BasicSymbolRef::BasicSymbolRef(DataRefImpl SymbolP,
188 const SymbolicFile *Owner)
189 : SymbolPimpl(SymbolP), OwningObject(Owner) {}
190
191 inline bool BasicSymbolRef::operator==(const BasicSymbolRef &Other) const {
192 return SymbolPimpl == Other.SymbolPimpl;
193 }
194
195 inline bool BasicSymbolRef::operator<(const BasicSymbolRef &Other) const {
196 return SymbolPimpl < Other.SymbolPimpl;
197 }
198
moveNext()199 inline void BasicSymbolRef::moveNext() {
200 return OwningObject->moveSymbolNext(SymbolPimpl);
201 }
202
printName(raw_ostream & OS)203 inline Error BasicSymbolRef::printName(raw_ostream &OS) const {
204 return OwningObject->printSymbolName(OS, SymbolPimpl);
205 }
206
getFlags()207 inline Expected<uint32_t> BasicSymbolRef::getFlags() const {
208 return OwningObject->getSymbolFlags(SymbolPimpl);
209 }
210
getRawDataRefImpl()211 inline DataRefImpl BasicSymbolRef::getRawDataRefImpl() const {
212 return SymbolPimpl;
213 }
214
getObject()215 inline const SymbolicFile *BasicSymbolRef::getObject() const {
216 return OwningObject;
217 }
218
219 } // end namespace object
220 } // end namespace llvm
221
222 #endif // LLVM_OBJECT_SYMBOLICFILE_H
223