/Users/buildslave/jenkins/workspace/clang-stage2-coverage-R/llvm/include/llvm/MC/MCMachObjectWriter.h
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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 |