1 //===- MCAssembler.h - Object File Generation -------------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 #ifndef LLVM_MC_MCASSEMBLER_H
11 #define LLVM_MC_MCASSEMBLER_H
13 #include "llvm/ADT/ArrayRef.h"
14 #include "llvm/ADT/STLExtras.h"
15 #include "llvm/ADT/SmallPtrSet.h"
16 #include "llvm/ADT/StringRef.h"
17 #include "llvm/ADT/iterator.h"
18 #include "llvm/ADT/iterator_range.h"
19 #include "llvm/BinaryFormat/MachO.h"
20 #include "llvm/MC/MCDirectives.h"
21 #include "llvm/MC/MCDwarf.h"
22 #include "llvm/MC/MCFixup.h"
23 #include "llvm/MC/MCFragment.h"
24 #include "llvm/MC/MCLinkerOptimizationHint.h"
25 #include "llvm/MC/MCSymbol.h"
44 // FIXME: This really doesn't belong here. See comments below.
45 struct IndirectSymbolData {
50 // FIXME: Ditto this. Purely so the Streamer and the ObjectWriter can talk
52 struct DataRegionData {
53 // This enum should be kept in sync w/ the mach-o definition in
54 // llvm/Object/MachOFormat.h.
55 enum KindTy { Data = 1, JumpTable8, JumpTable16, JumpTable32 } Kind;
61 friend class MCAsmLayout;
64 using SectionListType = std::vector<MCSection *>;
65 using SymbolDataListType = std::vector<const MCSymbol *>;
67 using const_iterator = pointee_iterator<SectionListType::const_iterator>;
68 using iterator = pointee_iterator<SectionListType::iterator>;
70 using const_symbol_iterator =
71 pointee_iterator<SymbolDataListType::const_iterator>;
72 using symbol_iterator = pointee_iterator<SymbolDataListType::iterator>;
74 using symbol_range = iterator_range<symbol_iterator>;
75 using const_symbol_range = iterator_range<const_symbol_iterator>;
77 using const_indirect_symbol_iterator =
78 std::vector<IndirectSymbolData>::const_iterator;
79 using indirect_symbol_iterator = std::vector<IndirectSymbolData>::iterator;
81 using const_data_region_iterator =
82 std::vector<DataRegionData>::const_iterator;
83 using data_region_iterator = std::vector<DataRegionData>::iterator;
85 /// MachO specific deployment target version info.
86 // A Major version of 0 indicates that no version information was supplied
87 // and so the corresponding load command should not be emitted.
88 using VersionInfoType = struct {
89 bool EmitBuildVersion;
91 MCVersionMinType Type; ///< Used when EmitBuildVersion==false.
92 MachO::PlatformType Platform; ///< Used when EmitBuildVersion==true.
102 std::unique_ptr<MCAsmBackend> Backend;
104 std::unique_ptr<MCCodeEmitter> Emitter;
106 std::unique_ptr<MCObjectWriter> Writer;
108 SectionListType Sections;
110 SymbolDataListType Symbols;
112 std::vector<IndirectSymbolData> IndirectSymbols;
114 std::vector<DataRegionData> DataRegions;
116 /// The list of linker options to propagate into the object file.
117 std::vector<std::vector<std::string>> LinkerOptions;
119 /// List of declared file names
120 std::vector<std::string> FileNames;
122 MCDwarfLineTableParams LTParams;
124 /// The set of function symbols for which a .thumb_func directive has
127 // FIXME: We really would like this in target specific code rather than
128 // here. Maybe when the relocation stuff moves to target specific,
129 // this can go with it? The streamer would need some target specific
131 mutable SmallPtrSet<const MCSymbol *, 32> ThumbFuncs;
133 /// The bundle alignment size currently set in the assembler.
135 /// By default it's 0, which means bundling is disabled.
136 unsigned BundleAlignSize;
139 bool SubsectionsViaSymbols : 1;
140 bool IncrementalLinkerCompatible : 1;
142 /// ELF specific e_header flags
143 // It would be good if there were an MCELFAssembler class to hold this.
144 // ELF header flags are used both by the integrated and standalone assemblers.
145 // Access to the flags is necessary in cases where assembler directives affect
146 // which flags to be set.
147 unsigned ELFHeaderEFlags;
149 /// Used to communicate Linker Optimization Hint information between
150 /// the Streamer and the .o writer
151 MCLOHContainer LOHContainer;
153 VersionInfoType VersionInfo;
155 /// Evaluate a fixup to a relocatable expression and the value which should be
156 /// placed into the fixup.
158 /// \param Layout The layout to use for evaluation.
159 /// \param Fixup The fixup to evaluate.
160 /// \param DF The fragment the fixup is inside.
161 /// \param Target [out] On return, the relocatable expression the fixup
163 /// \param Value [out] On return, the value of the fixup as currently laid
165 /// \param WasForced [out] On return, the value in the fixup is set to the
166 /// correct value if WasForced is true, even if evaluateFixup returns false.
167 /// \return Whether the fixup value was fully resolved. This is true if the
168 /// \p Value result is fixed, otherwise the value may change due to
170 bool evaluateFixup(const MCAsmLayout &Layout, const MCFixup &Fixup,
171 const MCFragment *DF, MCValue &Target,
172 uint64_t &Value, bool &WasForced) const;
174 /// Check whether a fixup can be satisfied, or whether it needs to be relaxed
175 /// (increased in size, in order to hold its value correctly).
176 bool fixupNeedsRelaxation(const MCFixup &Fixup, const MCRelaxableFragment *DF,
177 const MCAsmLayout &Layout) const;
179 /// Check whether the given fragment needs relaxation.
180 bool fragmentNeedsRelaxation(const MCRelaxableFragment *IF,
181 const MCAsmLayout &Layout) const;
183 /// Perform one layout iteration and return true if any offsets
185 bool layoutOnce(MCAsmLayout &Layout);
187 /// Perform one layout iteration of the given section and return true
188 /// if any offsets were adjusted.
189 bool layoutSectionOnce(MCAsmLayout &Layout, MCSection &Sec);
191 bool relaxInstruction(MCAsmLayout &Layout, MCRelaxableFragment &IF);
193 bool relaxPaddingFragment(MCAsmLayout &Layout, MCPaddingFragment &PF);
195 bool relaxLEB(MCAsmLayout &Layout, MCLEBFragment &IF);
197 bool relaxDwarfLineAddr(MCAsmLayout &Layout, MCDwarfLineAddrFragment &DF);
198 bool relaxDwarfCallFrameFragment(MCAsmLayout &Layout,
199 MCDwarfCallFrameFragment &DF);
200 bool relaxCVInlineLineTable(MCAsmLayout &Layout,
201 MCCVInlineLineTableFragment &DF);
202 bool relaxCVDefRange(MCAsmLayout &Layout, MCCVDefRangeFragment &DF);
204 /// finishLayout - Finalize a layout, including fragment lowering.
205 void finishLayout(MCAsmLayout &Layout);
207 std::tuple<MCValue, uint64_t, bool>
208 handleFixup(const MCAsmLayout &Layout, MCFragment &F, const MCFixup &Fixup);
211 std::vector<std::pair<StringRef, const MCSymbol *>> Symvers;
213 /// Construct a new assembler instance.
215 // FIXME: How are we going to parameterize this? Two obvious options are stay
216 // concrete and require clients to pass in a target like object. The other
217 // option is to make this abstract, and have targets provide concrete
218 // implementations as we do with AsmParser.
219 MCAssembler(MCContext &Context, std::unique_ptr<MCAsmBackend> Backend,
220 std::unique_ptr<MCCodeEmitter> Emitter,
221 std::unique_ptr<MCObjectWriter> Writer);
222 MCAssembler(const MCAssembler &) = delete;
223 MCAssembler &operator=(const MCAssembler &) = delete;
226 /// Compute the effective fragment size assuming it is laid out at the given
227 /// \p SectionAddress and \p FragmentOffset.
228 uint64_t computeFragmentSize(const MCAsmLayout &Layout,
229 const MCFragment &F) const;
231 /// Find the symbol which defines the atom containing the given symbol, or
232 /// null if there is no such symbol.
233 const MCSymbol *getAtom(const MCSymbol &S) const;
235 /// Check whether a particular symbol is visible to the linker and is required
236 /// in the symbol table, or whether it can be discarded by the assembler. This
237 /// also effects whether the assembler treats the label as potentially
238 /// defining a separate atom.
239 bool isSymbolLinkerVisible(const MCSymbol &SD) const;
241 /// Emit the section contents to \p OS.
242 void writeSectionData(raw_ostream &OS, const MCSection *Section,
243 const MCAsmLayout &Layout) const;
245 /// Check whether a given symbol has been flagged with .thumb_func.
246 bool isThumbFunc(const MCSymbol *Func) const;
248 /// Flag a function symbol as the target of a .thumb_func directive.
249 void setIsThumbFunc(const MCSymbol *Func) { ThumbFuncs.insert(Func); }
251 /// ELF e_header flags
252 unsigned getELFHeaderEFlags() const { return ELFHeaderEFlags; }
253 void setELFHeaderEFlags(unsigned Flags) { ELFHeaderEFlags = Flags; }
255 /// MachO deployment target version information.
256 const VersionInfoType &getVersionInfo() const { return VersionInfo; }
257 void setVersionMin(MCVersionMinType Type, unsigned Major, unsigned Minor,
259 VersionInfo.EmitBuildVersion = false;
260 VersionInfo.TypeOrPlatform.Type = Type;
261 VersionInfo.Major = Major;
262 VersionInfo.Minor = Minor;
263 VersionInfo.Update = Update;
265 void setBuildVersion(MachO::PlatformType Platform, unsigned Major,
266 unsigned Minor, unsigned Update) {
267 VersionInfo.EmitBuildVersion = true;
268 VersionInfo.TypeOrPlatform.Platform = Platform;
269 VersionInfo.Major = Major;
270 VersionInfo.Minor = Minor;
271 VersionInfo.Update = Update;
274 /// Reuse an assembler instance
278 MCContext &getContext() const { return Context; }
280 MCAsmBackend *getBackendPtr() const { return Backend.get(); }
282 MCCodeEmitter *getEmitterPtr() const { return Emitter.get(); }
284 MCObjectWriter *getWriterPtr() const { return Writer.get(); }
286 MCAsmBackend &getBackend() const { return *Backend; }
288 MCCodeEmitter &getEmitter() const { return *Emitter; }
290 MCObjectWriter &getWriter() const { return *Writer; }
292 MCDwarfLineTableParams getDWARFLinetableParams() const { return LTParams; }
293 void setDWARFLinetableParams(MCDwarfLineTableParams P) { LTParams = P; }
295 /// Finish - Do final processing and write the object to the output stream.
296 /// \p Writer is used for custom object writer (as the MCJIT does),
297 /// if not specified it is automatically created from backend.
300 // Layout all section and prepare them for emission.
301 void layout(MCAsmLayout &Layout);
303 // FIXME: This does not belong here.
304 bool getSubsectionsViaSymbols() const { return SubsectionsViaSymbols; }
305 void setSubsectionsViaSymbols(bool Value) { SubsectionsViaSymbols = Value; }
307 bool isIncrementalLinkerCompatible() const {
308 return IncrementalLinkerCompatible;
310 void setIncrementalLinkerCompatible(bool Value) {
311 IncrementalLinkerCompatible = Value;
314 bool getRelaxAll() const { return RelaxAll; }
315 void setRelaxAll(bool Value) { RelaxAll = Value; }
317 bool isBundlingEnabled() const { return BundleAlignSize != 0; }
319 unsigned getBundleAlignSize() const { return BundleAlignSize; }
321 void setBundleAlignSize(unsigned Size) {
322 assert((Size == 0 || !(Size & (Size - 1))) &&
323 "Expect a power-of-two bundle align size");
324 BundleAlignSize = Size;
327 /// \name Section List Access
330 iterator begin() { return Sections.begin(); }
331 const_iterator begin() const { return Sections.begin(); }
333 iterator end() { return Sections.end(); }
334 const_iterator end() const { return Sections.end(); }
336 size_t size() const { return Sections.size(); }
339 /// \name Symbol List Access
341 symbol_iterator symbol_begin() { return Symbols.begin(); }
342 const_symbol_iterator symbol_begin() const { return Symbols.begin(); }
344 symbol_iterator symbol_end() { return Symbols.end(); }
345 const_symbol_iterator symbol_end() const { return Symbols.end(); }
347 symbol_range symbols() { return make_range(symbol_begin(), symbol_end()); }
348 const_symbol_range symbols() const {
349 return make_range(symbol_begin(), symbol_end());
352 size_t symbol_size() const { return Symbols.size(); }
355 /// \name Indirect Symbol List Access
358 // FIXME: This is a total hack, this should not be here. Once things are
359 // factored so that the streamer has direct access to the .o writer, it can
361 std::vector<IndirectSymbolData> &getIndirectSymbols() {
362 return IndirectSymbols;
365 indirect_symbol_iterator indirect_symbol_begin() {
366 return IndirectSymbols.begin();
368 const_indirect_symbol_iterator indirect_symbol_begin() const {
369 return IndirectSymbols.begin();
372 indirect_symbol_iterator indirect_symbol_end() {
373 return IndirectSymbols.end();
375 const_indirect_symbol_iterator indirect_symbol_end() const {
376 return IndirectSymbols.end();
379 size_t indirect_symbol_size() const { return IndirectSymbols.size(); }
382 /// \name Linker Option List Access
385 std::vector<std::vector<std::string>> &getLinkerOptions() {
386 return LinkerOptions;
390 /// \name Data Region List Access
393 // FIXME: This is a total hack, this should not be here. Once things are
394 // factored so that the streamer has direct access to the .o writer, it can
396 std::vector<DataRegionData> &getDataRegions() { return DataRegions; }
398 data_region_iterator data_region_begin() { return DataRegions.begin(); }
399 const_data_region_iterator data_region_begin() const {
400 return DataRegions.begin();
403 data_region_iterator data_region_end() { return DataRegions.end(); }
404 const_data_region_iterator data_region_end() const {
405 return DataRegions.end();
408 size_t data_region_size() const { return DataRegions.size(); }
411 /// \name Data Region List Access
414 // FIXME: This is a total hack, this should not be here. Once things are
415 // factored so that the streamer has direct access to the .o writer, it can
417 MCLOHContainer &getLOHContainer() { return LOHContainer; }
418 const MCLOHContainer &getLOHContainer() const {
419 return const_cast<MCAssembler *>(this)->getLOHContainer();
422 struct CGProfileEntry {
423 const MCSymbolRefExpr *From;
424 const MCSymbolRefExpr *To;
427 std::vector<CGProfileEntry> CGProfile;
429 /// \name Backend Data Access
432 bool registerSection(MCSection &Section);
434 void registerSymbol(const MCSymbol &Symbol, bool *Created = nullptr);
436 ArrayRef<std::string> getFileNames() { return FileNames; }
438 void addFileName(StringRef FileName) {
439 if (!is_contained(FileNames, FileName))
440 FileNames.push_back(FileName);
443 /// Write the necessary bundle padding to \p OS.
444 /// Expects a fragment \p F containing instructions and its size \p FSize.
445 void writeFragmentPadding(raw_ostream &OS, const MCEncodedFragment &F,
446 uint64_t FSize) const;
453 /// Compute the amount of padding required before the fragment \p F to
454 /// obey bundling restrictions, where \p FOffset is the fragment's offset in
455 /// its section and \p FSize is the fragment's size.
456 uint64_t computeBundlePadding(const MCAssembler &Assembler,
457 const MCEncodedFragment *F, uint64_t FOffset,
460 } // end namespace llvm
462 #endif // LLVM_MC_MCASSEMBLER_H