Coverage Report

Created: 2019-07-24 05:18

/Users/buildslave/jenkins/workspace/clang-stage2-coverage-R/llvm/include/llvm/MC/MCMachObjectWriter.h
Line
Count
Source (jump to first uncovered line)
1
//===- llvm/MC/MCMachObjectWriter.h - Mach Object Writer --------*- 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
#ifndef LLVM_MC_MCMACHOBJECTWRITER_H
10
#define LLVM_MC_MCMACHOBJECTWRITER_H
11
12
#include "llvm/ADT/DenseMap.h"
13
#include "llvm/ADT/StringRef.h"
14
#include "llvm/BinaryFormat/MachO.h"
15
#include "llvm/MC/MCExpr.h"
16
#include "llvm/MC/MCObjectWriter.h"
17
#include "llvm/MC/MCSection.h"
18
#include "llvm/MC/StringTableBuilder.h"
19
#include <cstdint>
20
#include <memory>
21
#include <string>
22
#include <vector>
23
24
namespace llvm {
25
26
class MachObjectWriter;
27
28
class MCMachObjectTargetWriter : public MCObjectTargetWriter {
29
  const unsigned Is64Bit : 1;
30
  const uint32_t CPUType;
31
  const uint32_t CPUSubtype;
32
  unsigned LocalDifference_RIT;
33
34
protected:
35
  MCMachObjectTargetWriter(bool Is64Bit_, uint32_t CPUType_,
36
                           uint32_t CPUSubtype_);
37
38
0
  void setLocalDifferenceRelocationType(unsigned Type) {
39
0
    LocalDifference_RIT = Type;
40
0
  }
41
42
public:
43
  virtual ~MCMachObjectTargetWriter();
44
45
16.6k
  virtual Triple::ObjectFormatType getFormat() const { return Triple::MachO; }
46
0
  static bool classof(const MCObjectTargetWriter *W) {
47
0
    return W->getFormat() == Triple::MachO;
48
0
  }
49
50
  /// \name Lifetime Management
51
  /// @{
52
53
0
  virtual void reset() {}
54
55
  /// @}
56
57
  /// \name Accessors
58
  /// @{
59
60
1.78M
  bool is64Bit() const { return Is64Bit; }
61
3.08M
  uint32_t getCPUType() const { return CPUType; }
62
13.9k
  uint32_t getCPUSubtype() const { return CPUSubtype; }
63
0
  unsigned getLocalDifferenceRelocationType() const {
64
0
    return LocalDifference_RIT;
65
0
  }
66
67
  /// @}
68
69
  /// \name API
70
  /// @{
71
72
  virtual void recordRelocation(MachObjectWriter *Writer, MCAssembler &Asm,
73
                                const MCAsmLayout &Layout,
74
                                const MCFragment *Fragment,
75
                                const MCFixup &Fixup, MCValue Target,
76
                                uint64_t &FixedValue) = 0;
77
78
  /// @}
79
};
80
81
class MachObjectWriter : public MCObjectWriter {
82
  /// Helper struct for containing some precomputed information on symbols.
83
  struct MachSymbolData {
84
    const MCSymbol *Symbol;
85
    uint64_t StringIndex;
86
    uint8_t SectionIndex;
87
88
    // Support lexicographic sorting.
89
    bool operator<(const MachSymbolData &RHS) const;
90
  };
91
92
  /// The target specific Mach-O writer instance.
93
  std::unique_ptr<MCMachObjectTargetWriter> TargetObjectWriter;
94
95
  /// \name Relocation Data
96
  /// @{
97
98
  struct RelAndSymbol {
99
    const MCSymbol *Sym;
100
    MachO::any_relocation_info MRE;
101
    RelAndSymbol(const MCSymbol *Sym, const MachO::any_relocation_info &MRE)
102
3.59M
        : Sym(Sym), MRE(MRE) {}
103
  };
104
105
  DenseMap<const MCSection *, std::vector<RelAndSymbol>> Relocations;
106
  DenseMap<const MCSection *, unsigned> IndirectSymBase;
107
108
  SectionAddrMap SectionAddress;
109
110
  /// @}
111
  /// \name Symbol Table Data
112
  /// @{
113
114
  StringTableBuilder StringTable{StringTableBuilder::MachO};
115
  std::vector<MachSymbolData> LocalSymbolData;
116
  std::vector<MachSymbolData> ExternalSymbolData;
117
  std::vector<MachSymbolData> UndefinedSymbolData;
118
119
  /// @}
120
121
  MachSymbolData *findSymbolData(const MCSymbol &Sym);
122
123
  void writeWithPadding(StringRef Str, uint64_t Size);
124
125
public:
126
  MachObjectWriter(std::unique_ptr<MCMachObjectTargetWriter> MOTW,
127
                   raw_pwrite_stream &OS, bool IsLittleEndian)
128
      : TargetObjectWriter(std::move(MOTW)),
129
16.6k
        W(OS, IsLittleEndian ? support::little : support::big) {}
130
131
  support::endian::Writer W;
132
133
  const MCSymbol &findAliasedSymbol(const MCSymbol &Sym) const;
134
135
  /// \name Lifetime management Methods
136
  /// @{
137
138
  void reset() override;
139
140
  /// @}
141
142
  /// \name Utility Methods
143
  /// @{
144
145
  bool isFixupKindPCRel(const MCAssembler &Asm, unsigned Kind);
146
147
22.6k
  SectionAddrMap &getSectionAddressMap() { return SectionAddress; }
148
149
5.36M
  uint64_t getSectionAddress(const MCSection *Sec) const {
150
5.36M
    return SectionAddress.lookup(Sec);
151
5.36M
  }
152
  uint64_t getSymbolAddress(const MCSymbol &S, const MCAsmLayout &Layout) const;
153
154
  uint64_t getFragmentAddress(const MCFragment *Fragment,
155
                              const MCAsmLayout &Layout) const;
156
157
  uint64_t getPaddingSize(const MCSection *SD, const MCAsmLayout &Layout) const;
158
159
  bool doesSymbolRequireExternRelocation(const MCSymbol &S);
160
161
  /// @}
162
163
  /// \name Target Writer Proxy Accessors
164
  /// @{
165
166
1.78M
  bool is64Bit() const { return TargetObjectWriter->is64Bit(); }
167
3.07M
  bool isX86_64() const {
168
3.07M
    uint32_t CPUType = TargetObjectWriter->getCPUType();
169
3.07M
    return CPUType == MachO::CPU_TYPE_X86_64;
170
3.07M
  }
171
172
  /// @}
173
174
  void writeHeader(MachO::HeaderFileType Type, unsigned NumLoadCommands,
175
                   unsigned LoadCommandsSize, bool SubsectionsViaSymbols);
176
177
  /// Write a segment load command.
178
  ///
179
  /// \param NumSections The number of sections in this segment.
180
  /// \param SectionDataSize The total size of the sections.
181
  void writeSegmentLoadCommand(StringRef Name, unsigned NumSections,
182
                               uint64_t VMAddr, uint64_t VMSize,
183
                               uint64_t SectionDataStartOffset,
184
                               uint64_t SectionDataSize, uint32_t MaxProt,
185
                               uint32_t InitProt);
186
187
  void writeSection(const MCAsmLayout &Layout, const MCSection &Sec,
188
                    uint64_t VMAddr, uint64_t FileOffset, unsigned Flags,
189
                    uint64_t RelocationsStart, unsigned NumRelocations);
190
191
  void writeSymtabLoadCommand(uint32_t SymbolOffset, uint32_t NumSymbols,
192
                              uint32_t StringTableOffset,
193
                              uint32_t StringTableSize);
194
195
  void writeDysymtabLoadCommand(
196
      uint32_t FirstLocalSymbol, uint32_t NumLocalSymbols,
197
      uint32_t FirstExternalSymbol, uint32_t NumExternalSymbols,
198
      uint32_t FirstUndefinedSymbol, uint32_t NumUndefinedSymbols,
199
      uint32_t IndirectSymbolOffset, uint32_t NumIndirectSymbols);
200
201
  void writeNlist(MachSymbolData &MSD, const MCAsmLayout &Layout);
202
203
  void writeLinkeditLoadCommand(uint32_t Type, uint32_t DataOffset,
204
                                uint32_t DataSize);
205
206
  void writeLinkerOptionsLoadCommand(const std::vector<std::string> &Options);
207
208
  // FIXME: We really need to improve the relocation validation. Basically, we
209
  // want to implement a separate computation which evaluates the relocation
210
  // entry as the linker would, and verifies that the resultant fixup value is
211
  // exactly what the encoder wanted. This will catch several classes of
212
  // problems:
213
  //
214
  //  - Relocation entry bugs, the two algorithms are unlikely to have the same
215
  //    exact bug.
216
  //
217
  //  - Relaxation issues, where we forget to relax something.
218
  //
219
  //  - Input errors, where something cannot be correctly encoded. 'as' allows
220
  //    these through in many cases.
221
222
  // Add a relocation to be output in the object file. At the time this is
223
  // called, the symbol indexes are not know, so if the relocation refers
224
  // to a symbol it should be passed as \p RelSymbol so that it can be updated
225
  // afterwards. If the relocation doesn't refer to a symbol, nullptr should be
226
  // used.
227
  void addRelocation(const MCSymbol *RelSymbol, const MCSection *Sec,
228
3.59M
                     MachO::any_relocation_info &MRE) {
229
3.59M
    RelAndSymbol P(RelSymbol, MRE);
230
3.59M
    Relocations[Sec].push_back(P);
231
3.59M
  }
232
233
  void recordScatteredRelocation(const MCAssembler &Asm,
234
                                 const MCAsmLayout &Layout,
235
                                 const MCFragment *Fragment,
236
                                 const MCFixup &Fixup, MCValue Target,
237
                                 unsigned Log2Size, uint64_t &FixedValue);
238
239
  void recordTLVPRelocation(const MCAssembler &Asm, const MCAsmLayout &Layout,
240
                            const MCFragment *Fragment, const MCFixup &Fixup,
241
                            MCValue Target, uint64_t &FixedValue);
242
243
  void recordRelocation(MCAssembler &Asm, const MCAsmLayout &Layout,
244
                        const MCFragment *Fragment, const MCFixup &Fixup,
245
                        MCValue Target, uint64_t &FixedValue) override;
246
247
  void bindIndirectSymbols(MCAssembler &Asm);
248
249
  /// Compute the symbol table data.
250
  void computeSymbolTable(MCAssembler &Asm,
251
                          std::vector<MachSymbolData> &LocalSymbolData,
252
                          std::vector<MachSymbolData> &ExternalSymbolData,
253
                          std::vector<MachSymbolData> &UndefinedSymbolData);
254
255
  void computeSectionAddresses(const MCAssembler &Asm,
256
                               const MCAsmLayout &Layout);
257
258
  void executePostLayoutBinding(MCAssembler &Asm,
259
                                const MCAsmLayout &Layout) override;
260
261
  bool isSymbolRefDifferenceFullyResolvedImpl(const MCAssembler &Asm,
262
                                              const MCSymbol &A,
263
                                              const MCSymbol &B,
264
                                              bool InSet) const override;
265
266
  bool isSymbolRefDifferenceFullyResolvedImpl(const MCAssembler &Asm,
267
                                              const MCSymbol &SymA,
268
                                              const MCFragment &FB, bool InSet,
269
                                              bool IsPCRel) const override;
270
271
  uint64_t writeObject(MCAssembler &Asm, const MCAsmLayout &Layout) override;
272
};
273
274
/// Construct a new Mach-O writer instance.
275
///
276
/// This routine takes ownership of the target writer subclass.
277
///
278
/// \param MOTW - The target specific Mach-O writer subclass.
279
/// \param OS - The stream to write to.
280
/// \returns The constructed object writer.
281
std::unique_ptr<MCObjectWriter>
282
createMachObjectWriter(std::unique_ptr<MCMachObjectTargetWriter> MOTW,
283
                       raw_pwrite_stream &OS, bool IsLittleEndian);
284
285
} // end namespace llvm
286
287
#endif // LLVM_MC_MCMACHOBJECTWRITER_H