xref: /llvm-project/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp (revision 3624bdf60aa49dd3943ac4a2cdb552143df3964a)
1 //===--- Bitcode/Writer/BitcodeWriter.cpp - Bitcode Writer ----------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // Bitcode writer implementation.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "llvm/Bitcode/BitcodeWriter.h"
15 #include "ValueEnumerator.h"
16 #include "llvm/ADT/StringExtras.h"
17 #include "llvm/ADT/Triple.h"
18 #include "llvm/Bitcode/BitstreamWriter.h"
19 #include "llvm/Bitcode/LLVMBitCodes.h"
20 #include "llvm/IR/CallSite.h"
21 #include "llvm/IR/Constants.h"
22 #include "llvm/IR/DebugInfoMetadata.h"
23 #include "llvm/IR/DerivedTypes.h"
24 #include "llvm/IR/InlineAsm.h"
25 #include "llvm/IR/Instructions.h"
26 #include "llvm/IR/LLVMContext.h"
27 #include "llvm/IR/Module.h"
28 #include "llvm/IR/Operator.h"
29 #include "llvm/IR/UseListOrder.h"
30 #include "llvm/IR/ValueSymbolTable.h"
31 #include "llvm/Support/ErrorHandling.h"
32 #include "llvm/Support/MathExtras.h"
33 #include "llvm/Support/Program.h"
34 #include "llvm/Support/SHA1.h"
35 #include "llvm/Support/raw_ostream.h"
36 #include <cctype>
37 #include <map>
38 using namespace llvm;
39 
40 namespace {
41 /// These are manifest constants used by the bitcode writer. They do not need to
42 /// be kept in sync with the reader, but need to be consistent within this file.
43 enum {
44   // VALUE_SYMTAB_BLOCK abbrev id's.
45   VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
46   VST_ENTRY_7_ABBREV,
47   VST_ENTRY_6_ABBREV,
48   VST_BBENTRY_6_ABBREV,
49 
50   // CONSTANTS_BLOCK abbrev id's.
51   CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
52   CONSTANTS_INTEGER_ABBREV,
53   CONSTANTS_CE_CAST_Abbrev,
54   CONSTANTS_NULL_Abbrev,
55 
56   // FUNCTION_BLOCK abbrev id's.
57   FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
58   FUNCTION_INST_BINOP_ABBREV,
59   FUNCTION_INST_BINOP_FLAGS_ABBREV,
60   FUNCTION_INST_CAST_ABBREV,
61   FUNCTION_INST_RET_VOID_ABBREV,
62   FUNCTION_INST_RET_VAL_ABBREV,
63   FUNCTION_INST_UNREACHABLE_ABBREV,
64   FUNCTION_INST_GEP_ABBREV,
65 };
66 
67 /// Abstract class to manage the bitcode writing, subclassed for each bitcode
68 /// file type. Owns the BitstreamWriter, and includes the main entry point for
69 /// writing.
70 class BitcodeWriter {
71 protected:
72   /// Pointer to the buffer allocated by caller for bitcode writing.
73   const SmallVectorImpl<char> &Buffer;
74 
75   /// The stream created and owned by the BitodeWriter.
76   BitstreamWriter Stream;
77 
78   /// Saves the offset of the VSTOffset record that must eventually be
79   /// backpatched with the offset of the actual VST.
80   uint64_t VSTOffsetPlaceholder = 0;
81 
82 public:
83   /// Constructs a BitcodeWriter object, and initializes a BitstreamRecord,
84   /// writing to the provided \p Buffer.
85   BitcodeWriter(SmallVectorImpl<char> &Buffer)
86       : Buffer(Buffer), Stream(Buffer) {}
87 
88   virtual ~BitcodeWriter() = default;
89 
90   /// Main entry point to write the bitcode file, which writes the bitcode
91   /// header and will then invoke the virtual writeBlocks() method.
92   void write();
93 
94 private:
95   /// Derived classes must implement this to write the corresponding blocks for
96   /// that bitcode file type.
97   virtual void writeBlocks() = 0;
98 
99 protected:
100   bool hasVSTOffsetPlaceholder() { return VSTOffsetPlaceholder != 0; }
101   void writeValueSymbolTableForwardDecl();
102   void writeBitcodeHeader();
103 };
104 
105 /// Class to manage the bitcode writing for a module.
106 class ModuleBitcodeWriter : public BitcodeWriter {
107   /// The Module to write to bitcode.
108   const Module &M;
109 
110   /// Enumerates ids for all values in the module.
111   ValueEnumerator VE;
112 
113   /// Optional per-module index to write for ThinLTO.
114   const ModuleSummaryIndex *Index;
115 
116   /// True if a module hash record should be written.
117   bool GenerateHash;
118 
119   /// The start bit of the module block, for use in generating a module hash
120   uint64_t BitcodeStartBit = 0;
121 
122   /// Map that holds the correspondence between GUIDs in the summary index,
123   /// that came from indirect call profiles, and a value id generated by this
124   /// class to use in the VST and summary block records.
125   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
126 
127   /// Tracks the last value id recorded in the GUIDToValueMap.
128   unsigned GlobalValueId;
129 
130 public:
131   /// Constructs a ModuleBitcodeWriter object for the given Module,
132   /// writing to the provided \p Buffer.
133   ModuleBitcodeWriter(const Module *M, SmallVectorImpl<char> &Buffer,
134                       bool ShouldPreserveUseListOrder,
135                       const ModuleSummaryIndex *Index, bool GenerateHash)
136       : BitcodeWriter(Buffer), M(*M), VE(*M, ShouldPreserveUseListOrder),
137         Index(Index), GenerateHash(GenerateHash) {
138     // Save the start bit of the actual bitcode, in case there is space
139     // saved at the start for the darwin header above. The reader stream
140     // will start at the bitcode, and we need the offset of the VST
141     // to line up.
142     BitcodeStartBit = Stream.GetCurrentBitNo();
143 
144     // Assign ValueIds to any callee values in the index that came from
145     // indirect call profiles and were recorded as a GUID not a Value*
146     // (which would have been assigned an ID by the ValueEnumerator).
147     // The starting ValueId is just after the number of values in the
148     // ValueEnumerator, so that they can be emitted in the VST.
149     GlobalValueId = VE.getValues().size();
150     if (!Index)
151       return;
152     for (const auto &GUIDSummaryLists : *Index)
153       // Examine all summaries for this GUID.
154       for (auto &Summary : GUIDSummaryLists.second)
155         if (auto FS = dyn_cast<FunctionSummary>(Summary.get()))
156           // For each call in the function summary, see if the call
157           // is to a GUID (which means it is for an indirect call,
158           // otherwise we would have a Value for it). If so, synthesize
159           // a value id.
160           for (auto &CallEdge : FS->calls())
161             if (CallEdge.first.isGUID())
162               assignValueId(CallEdge.first.getGUID());
163   }
164 
165 private:
166   /// Main entry point for writing a module to bitcode, invoked by
167   /// BitcodeWriter::write() after it writes the header.
168   void writeBlocks() override;
169 
170   /// Create the "IDENTIFICATION_BLOCK_ID" containing a single string with the
171   /// current llvm version, and a record for the epoch number.
172   void writeIdentificationBlock();
173 
174   /// Emit the current module to the bitstream.
175   void writeModule();
176 
177   uint64_t bitcodeStartBit() { return BitcodeStartBit; }
178 
179   void writeStringRecord(unsigned Code, StringRef Str, unsigned AbbrevToUse);
180   void writeAttributeGroupTable();
181   void writeAttributeTable();
182   void writeTypeTable();
183   void writeComdats();
184   void writeModuleInfo();
185   void writeValueAsMetadata(const ValueAsMetadata *MD,
186                             SmallVectorImpl<uint64_t> &Record);
187   void writeMDTuple(const MDTuple *N, SmallVectorImpl<uint64_t> &Record,
188                     unsigned Abbrev);
189   unsigned createDILocationAbbrev();
190   void writeDILocation(const DILocation *N, SmallVectorImpl<uint64_t> &Record,
191                        unsigned &Abbrev);
192   unsigned createGenericDINodeAbbrev();
193   void writeGenericDINode(const GenericDINode *N,
194                           SmallVectorImpl<uint64_t> &Record, unsigned &Abbrev);
195   void writeDISubrange(const DISubrange *N, SmallVectorImpl<uint64_t> &Record,
196                        unsigned Abbrev);
197   void writeDIEnumerator(const DIEnumerator *N,
198                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
199   void writeDIBasicType(const DIBasicType *N, SmallVectorImpl<uint64_t> &Record,
200                         unsigned Abbrev);
201   void writeDIDerivedType(const DIDerivedType *N,
202                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
203   void writeDICompositeType(const DICompositeType *N,
204                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
205   void writeDISubroutineType(const DISubroutineType *N,
206                              SmallVectorImpl<uint64_t> &Record,
207                              unsigned Abbrev);
208   void writeDIFile(const DIFile *N, SmallVectorImpl<uint64_t> &Record,
209                    unsigned Abbrev);
210   void writeDICompileUnit(const DICompileUnit *N,
211                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
212   void writeDISubprogram(const DISubprogram *N,
213                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
214   void writeDILexicalBlock(const DILexicalBlock *N,
215                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
216   void writeDILexicalBlockFile(const DILexicalBlockFile *N,
217                                SmallVectorImpl<uint64_t> &Record,
218                                unsigned Abbrev);
219   void writeDINamespace(const DINamespace *N, SmallVectorImpl<uint64_t> &Record,
220                         unsigned Abbrev);
221   void writeDIMacro(const DIMacro *N, SmallVectorImpl<uint64_t> &Record,
222                     unsigned Abbrev);
223   void writeDIMacroFile(const DIMacroFile *N, SmallVectorImpl<uint64_t> &Record,
224                         unsigned Abbrev);
225   void writeDIModule(const DIModule *N, SmallVectorImpl<uint64_t> &Record,
226                      unsigned Abbrev);
227   void writeDITemplateTypeParameter(const DITemplateTypeParameter *N,
228                                     SmallVectorImpl<uint64_t> &Record,
229                                     unsigned Abbrev);
230   void writeDITemplateValueParameter(const DITemplateValueParameter *N,
231                                      SmallVectorImpl<uint64_t> &Record,
232                                      unsigned Abbrev);
233   void writeDIGlobalVariable(const DIGlobalVariable *N,
234                              SmallVectorImpl<uint64_t> &Record,
235                              unsigned Abbrev);
236   void writeDILocalVariable(const DILocalVariable *N,
237                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
238   void writeDIExpression(const DIExpression *N,
239                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
240   void writeDIObjCProperty(const DIObjCProperty *N,
241                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
242   void writeDIImportedEntity(const DIImportedEntity *N,
243                              SmallVectorImpl<uint64_t> &Record,
244                              unsigned Abbrev);
245   unsigned createNamedMetadataAbbrev();
246   void writeNamedMetadata(SmallVectorImpl<uint64_t> &Record);
247   unsigned createMetadataStringsAbbrev();
248   void writeMetadataStrings(ArrayRef<const Metadata *> Strings,
249                             SmallVectorImpl<uint64_t> &Record);
250   void writeMetadataRecords(ArrayRef<const Metadata *> MDs,
251                             SmallVectorImpl<uint64_t> &Record);
252   void writeModuleMetadata();
253   void writeFunctionMetadata(const Function &F);
254   void writeFunctionMetadataAttachment(const Function &F);
255   void writeGlobalVariableMetadataAttachment(const GlobalVariable &GV);
256   void pushGlobalMetadataAttachment(SmallVectorImpl<uint64_t> &Record,
257                                     const GlobalObject &GO);
258   void writeModuleMetadataKinds();
259   void writeOperandBundleTags();
260   void writeConstants(unsigned FirstVal, unsigned LastVal, bool isGlobal);
261   void writeModuleConstants();
262   bool pushValueAndType(const Value *V, unsigned InstID,
263                         SmallVectorImpl<unsigned> &Vals);
264   void writeOperandBundles(ImmutableCallSite CS, unsigned InstID);
265   void pushValue(const Value *V, unsigned InstID,
266                  SmallVectorImpl<unsigned> &Vals);
267   void pushValueSigned(const Value *V, unsigned InstID,
268                        SmallVectorImpl<uint64_t> &Vals);
269   void writeInstruction(const Instruction &I, unsigned InstID,
270                         SmallVectorImpl<unsigned> &Vals);
271   void writeValueSymbolTable(
272       const ValueSymbolTable &VST, bool IsModuleLevel = false,
273       DenseMap<const Function *, uint64_t> *FunctionToBitcodeIndex = nullptr);
274   void writeUseList(UseListOrder &&Order);
275   void writeUseListBlock(const Function *F);
276   void
277   writeFunction(const Function &F,
278                 DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
279   void writeBlockInfo();
280   void writePerModuleFunctionSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
281                                            GlobalValueSummary *Summary,
282                                            unsigned ValueID,
283                                            unsigned FSCallsAbbrev,
284                                            unsigned FSCallsProfileAbbrev,
285                                            const Function &F);
286   void writeModuleLevelReferences(const GlobalVariable &V,
287                                   SmallVector<uint64_t, 64> &NameVals,
288                                   unsigned FSModRefsAbbrev);
289   void writePerModuleGlobalValueSummary();
290   void writeModuleHash(size_t BlockStartPos);
291 
292   void assignValueId(GlobalValue::GUID ValGUID) {
293     GUIDToValueIdMap[ValGUID] = ++GlobalValueId;
294   }
295   unsigned getValueId(GlobalValue::GUID ValGUID) {
296     const auto &VMI = GUIDToValueIdMap.find(ValGUID);
297     // Expect that any GUID value had a value Id assigned by an
298     // earlier call to assignValueId.
299     assert(VMI != GUIDToValueIdMap.end() &&
300            "GUID does not have assigned value Id");
301     return VMI->second;
302   }
303   // Helper to get the valueId for the type of value recorded in VI.
304   unsigned getValueId(ValueInfo VI) {
305     if (VI.isGUID())
306       return getValueId(VI.getGUID());
307     return VE.getValueID(VI.getValue());
308   }
309   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
310 };
311 
312 /// Class to manage the bitcode writing for a combined index.
313 class IndexBitcodeWriter : public BitcodeWriter {
314   /// The combined index to write to bitcode.
315   const ModuleSummaryIndex &Index;
316 
317   /// When writing a subset of the index for distributed backends, client
318   /// provides a map of modules to the corresponding GUIDs/summaries to write.
319   const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex;
320 
321   /// Map that holds the correspondence between the GUID used in the combined
322   /// index and a value id generated by this class to use in references.
323   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
324 
325   /// Tracks the last value id recorded in the GUIDToValueMap.
326   unsigned GlobalValueId = 0;
327 
328 public:
329   /// Constructs a IndexBitcodeWriter object for the given combined index,
330   /// writing to the provided \p Buffer. When writing a subset of the index
331   /// for a distributed backend, provide a \p ModuleToSummariesForIndex map.
332   IndexBitcodeWriter(SmallVectorImpl<char> &Buffer,
333                      const ModuleSummaryIndex &Index,
334                      const std::map<std::string, GVSummaryMapTy>
335                          *ModuleToSummariesForIndex = nullptr)
336       : BitcodeWriter(Buffer), Index(Index),
337         ModuleToSummariesForIndex(ModuleToSummariesForIndex) {
338     // Assign unique value ids to all summaries to be written, for use
339     // in writing out the call graph edges. Save the mapping from GUID
340     // to the new global value id to use when writing those edges, which
341     // are currently saved in the index in terms of GUID.
342     for (const auto &I : *this)
343       GUIDToValueIdMap[I.first] = ++GlobalValueId;
344   }
345 
346   /// The below iterator returns the GUID and associated summary.
347   typedef std::pair<GlobalValue::GUID, GlobalValueSummary *> GVInfo;
348 
349   /// Iterator over the value GUID and summaries to be written to bitcode,
350   /// hides the details of whether they are being pulled from the entire
351   /// index or just those in a provided ModuleToSummariesForIndex map.
352   class iterator
353       : public llvm::iterator_facade_base<iterator, std::forward_iterator_tag,
354                                           GVInfo> {
355     /// Enables access to parent class.
356     const IndexBitcodeWriter &Writer;
357 
358     // Iterators used when writing only those summaries in a provided
359     // ModuleToSummariesForIndex map:
360 
361     /// Points to the last element in outer ModuleToSummariesForIndex map.
362     std::map<std::string, GVSummaryMapTy>::const_iterator ModuleSummariesBack;
363     /// Iterator on outer ModuleToSummariesForIndex map.
364     std::map<std::string, GVSummaryMapTy>::const_iterator ModuleSummariesIter;
365     /// Iterator on an inner global variable summary map.
366     GVSummaryMapTy::const_iterator ModuleGVSummariesIter;
367 
368     // Iterators used when writing all summaries in the index:
369 
370     /// Points to the last element in the Index outer GlobalValueMap.
371     const_gvsummary_iterator IndexSummariesBack;
372     /// Iterator on outer GlobalValueMap.
373     const_gvsummary_iterator IndexSummariesIter;
374     /// Iterator on an inner GlobalValueSummaryList.
375     GlobalValueSummaryList::const_iterator IndexGVSummariesIter;
376 
377   public:
378     /// Construct iterator from parent \p Writer and indicate if we are
379     /// constructing the end iterator.
380     iterator(const IndexBitcodeWriter &Writer, bool IsAtEnd) : Writer(Writer) {
381       // Set up the appropriate set of iterators given whether we are writing
382       // the full index or just a subset.
383       // Can't setup the Back or inner iterators if the corresponding map
384       // is empty. This will be handled specially in operator== as well.
385       if (Writer.ModuleToSummariesForIndex &&
386           !Writer.ModuleToSummariesForIndex->empty()) {
387         for (ModuleSummariesBack = Writer.ModuleToSummariesForIndex->begin();
388              std::next(ModuleSummariesBack) !=
389              Writer.ModuleToSummariesForIndex->end();
390              ModuleSummariesBack++)
391           ;
392         ModuleSummariesIter = !IsAtEnd
393                                   ? Writer.ModuleToSummariesForIndex->begin()
394                                   : ModuleSummariesBack;
395         ModuleGVSummariesIter = !IsAtEnd ? ModuleSummariesIter->second.begin()
396                                          : ModuleSummariesBack->second.end();
397       } else if (!Writer.ModuleToSummariesForIndex &&
398                  Writer.Index.begin() != Writer.Index.end()) {
399         for (IndexSummariesBack = Writer.Index.begin();
400              std::next(IndexSummariesBack) != Writer.Index.end();
401              IndexSummariesBack++)
402           ;
403         IndexSummariesIter =
404             !IsAtEnd ? Writer.Index.begin() : IndexSummariesBack;
405         IndexGVSummariesIter = !IsAtEnd ? IndexSummariesIter->second.begin()
406                                         : IndexSummariesBack->second.end();
407       }
408     }
409 
410     /// Increment the appropriate set of iterators.
411     iterator &operator++() {
412       // First the inner iterator is incremented, then if it is at the end
413       // and there are more outer iterations to go, the inner is reset to
414       // the start of the next inner list.
415       if (Writer.ModuleToSummariesForIndex) {
416         ++ModuleGVSummariesIter;
417         if (ModuleGVSummariesIter == ModuleSummariesIter->second.end() &&
418             ModuleSummariesIter != ModuleSummariesBack) {
419           ++ModuleSummariesIter;
420           ModuleGVSummariesIter = ModuleSummariesIter->second.begin();
421         }
422       } else {
423         ++IndexGVSummariesIter;
424         if (IndexGVSummariesIter == IndexSummariesIter->second.end() &&
425             IndexSummariesIter != IndexSummariesBack) {
426           ++IndexSummariesIter;
427           IndexGVSummariesIter = IndexSummariesIter->second.begin();
428         }
429       }
430       return *this;
431     }
432 
433     /// Access the <GUID,GlobalValueSummary*> pair corresponding to the current
434     /// outer and inner iterator positions.
435     GVInfo operator*() {
436       if (Writer.ModuleToSummariesForIndex)
437         return std::make_pair(ModuleGVSummariesIter->first,
438                               ModuleGVSummariesIter->second);
439       return std::make_pair(IndexSummariesIter->first,
440                             IndexGVSummariesIter->get());
441     }
442 
443     /// Checks if the iterators are equal, with special handling for empty
444     /// indexes.
445     bool operator==(const iterator &RHS) const {
446       if (Writer.ModuleToSummariesForIndex) {
447         // First ensure that both are writing the same subset.
448         if (Writer.ModuleToSummariesForIndex !=
449             RHS.Writer.ModuleToSummariesForIndex)
450           return false;
451         // Already determined above that maps are the same, so if one is
452         // empty, they both are.
453         if (Writer.ModuleToSummariesForIndex->empty())
454           return true;
455         // Ensure the ModuleGVSummariesIter are iterating over the same
456         // container before checking them below.
457         if (ModuleSummariesIter != RHS.ModuleSummariesIter)
458           return false;
459         return ModuleGVSummariesIter == RHS.ModuleGVSummariesIter;
460       }
461       // First ensure RHS also writing the full index, and that both are
462       // writing the same full index.
463       if (RHS.Writer.ModuleToSummariesForIndex ||
464           &Writer.Index != &RHS.Writer.Index)
465         return false;
466       // Already determined above that maps are the same, so if one is
467       // empty, they both are.
468       if (Writer.Index.begin() == Writer.Index.end())
469         return true;
470       // Ensure the IndexGVSummariesIter are iterating over the same
471       // container before checking them below.
472       if (IndexSummariesIter != RHS.IndexSummariesIter)
473         return false;
474       return IndexGVSummariesIter == RHS.IndexGVSummariesIter;
475     }
476   };
477 
478   /// Obtain the start iterator over the summaries to be written.
479   iterator begin() { return iterator(*this, /*IsAtEnd=*/false); }
480   /// Obtain the end iterator over the summaries to be written.
481   iterator end() { return iterator(*this, /*IsAtEnd=*/true); }
482 
483 private:
484   /// Main entry point for writing a combined index to bitcode, invoked by
485   /// BitcodeWriter::write() after it writes the header.
486   void writeBlocks() override;
487 
488   void writeIndex();
489   void writeModStrings();
490   void writeCombinedValueSymbolTable();
491   void writeCombinedGlobalValueSummary();
492 
493   /// Indicates whether the provided \p ModulePath should be written into
494   /// the module string table, e.g. if full index written or if it is in
495   /// the provided subset.
496   bool doIncludeModule(StringRef ModulePath) {
497     return !ModuleToSummariesForIndex ||
498            ModuleToSummariesForIndex->count(ModulePath);
499   }
500 
501   bool hasValueId(GlobalValue::GUID ValGUID) {
502     const auto &VMI = GUIDToValueIdMap.find(ValGUID);
503     return VMI != GUIDToValueIdMap.end();
504   }
505   unsigned getValueId(GlobalValue::GUID ValGUID) {
506     const auto &VMI = GUIDToValueIdMap.find(ValGUID);
507     // If this GUID doesn't have an entry, assign one.
508     if (VMI == GUIDToValueIdMap.end()) {
509       GUIDToValueIdMap[ValGUID] = ++GlobalValueId;
510       return GlobalValueId;
511     } else {
512       return VMI->second;
513     }
514   }
515   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
516 };
517 } // end anonymous namespace
518 
519 static unsigned getEncodedCastOpcode(unsigned Opcode) {
520   switch (Opcode) {
521   default: llvm_unreachable("Unknown cast instruction!");
522   case Instruction::Trunc   : return bitc::CAST_TRUNC;
523   case Instruction::ZExt    : return bitc::CAST_ZEXT;
524   case Instruction::SExt    : return bitc::CAST_SEXT;
525   case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
526   case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
527   case Instruction::UIToFP  : return bitc::CAST_UITOFP;
528   case Instruction::SIToFP  : return bitc::CAST_SITOFP;
529   case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
530   case Instruction::FPExt   : return bitc::CAST_FPEXT;
531   case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
532   case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
533   case Instruction::BitCast : return bitc::CAST_BITCAST;
534   case Instruction::AddrSpaceCast: return bitc::CAST_ADDRSPACECAST;
535   }
536 }
537 
538 static unsigned getEncodedBinaryOpcode(unsigned Opcode) {
539   switch (Opcode) {
540   default: llvm_unreachable("Unknown binary instruction!");
541   case Instruction::Add:
542   case Instruction::FAdd: return bitc::BINOP_ADD;
543   case Instruction::Sub:
544   case Instruction::FSub: return bitc::BINOP_SUB;
545   case Instruction::Mul:
546   case Instruction::FMul: return bitc::BINOP_MUL;
547   case Instruction::UDiv: return bitc::BINOP_UDIV;
548   case Instruction::FDiv:
549   case Instruction::SDiv: return bitc::BINOP_SDIV;
550   case Instruction::URem: return bitc::BINOP_UREM;
551   case Instruction::FRem:
552   case Instruction::SRem: return bitc::BINOP_SREM;
553   case Instruction::Shl:  return bitc::BINOP_SHL;
554   case Instruction::LShr: return bitc::BINOP_LSHR;
555   case Instruction::AShr: return bitc::BINOP_ASHR;
556   case Instruction::And:  return bitc::BINOP_AND;
557   case Instruction::Or:   return bitc::BINOP_OR;
558   case Instruction::Xor:  return bitc::BINOP_XOR;
559   }
560 }
561 
562 static unsigned getEncodedRMWOperation(AtomicRMWInst::BinOp Op) {
563   switch (Op) {
564   default: llvm_unreachable("Unknown RMW operation!");
565   case AtomicRMWInst::Xchg: return bitc::RMW_XCHG;
566   case AtomicRMWInst::Add: return bitc::RMW_ADD;
567   case AtomicRMWInst::Sub: return bitc::RMW_SUB;
568   case AtomicRMWInst::And: return bitc::RMW_AND;
569   case AtomicRMWInst::Nand: return bitc::RMW_NAND;
570   case AtomicRMWInst::Or: return bitc::RMW_OR;
571   case AtomicRMWInst::Xor: return bitc::RMW_XOR;
572   case AtomicRMWInst::Max: return bitc::RMW_MAX;
573   case AtomicRMWInst::Min: return bitc::RMW_MIN;
574   case AtomicRMWInst::UMax: return bitc::RMW_UMAX;
575   case AtomicRMWInst::UMin: return bitc::RMW_UMIN;
576   }
577 }
578 
579 static unsigned getEncodedOrdering(AtomicOrdering Ordering) {
580   switch (Ordering) {
581   case AtomicOrdering::NotAtomic: return bitc::ORDERING_NOTATOMIC;
582   case AtomicOrdering::Unordered: return bitc::ORDERING_UNORDERED;
583   case AtomicOrdering::Monotonic: return bitc::ORDERING_MONOTONIC;
584   case AtomicOrdering::Acquire: return bitc::ORDERING_ACQUIRE;
585   case AtomicOrdering::Release: return bitc::ORDERING_RELEASE;
586   case AtomicOrdering::AcquireRelease: return bitc::ORDERING_ACQREL;
587   case AtomicOrdering::SequentiallyConsistent: return bitc::ORDERING_SEQCST;
588   }
589   llvm_unreachable("Invalid ordering");
590 }
591 
592 static unsigned getEncodedSynchScope(SynchronizationScope SynchScope) {
593   switch (SynchScope) {
594   case SingleThread: return bitc::SYNCHSCOPE_SINGLETHREAD;
595   case CrossThread: return bitc::SYNCHSCOPE_CROSSTHREAD;
596   }
597   llvm_unreachable("Invalid synch scope");
598 }
599 
600 void ModuleBitcodeWriter::writeStringRecord(unsigned Code, StringRef Str,
601                                             unsigned AbbrevToUse) {
602   SmallVector<unsigned, 64> Vals;
603 
604   // Code: [strchar x N]
605   for (unsigned i = 0, e = Str.size(); i != e; ++i) {
606     if (AbbrevToUse && !BitCodeAbbrevOp::isChar6(Str[i]))
607       AbbrevToUse = 0;
608     Vals.push_back(Str[i]);
609   }
610 
611   // Emit the finished record.
612   Stream.EmitRecord(Code, Vals, AbbrevToUse);
613 }
614 
615 static uint64_t getAttrKindEncoding(Attribute::AttrKind Kind) {
616   switch (Kind) {
617   case Attribute::Alignment:
618     return bitc::ATTR_KIND_ALIGNMENT;
619   case Attribute::AllocSize:
620     return bitc::ATTR_KIND_ALLOC_SIZE;
621   case Attribute::AlwaysInline:
622     return bitc::ATTR_KIND_ALWAYS_INLINE;
623   case Attribute::ArgMemOnly:
624     return bitc::ATTR_KIND_ARGMEMONLY;
625   case Attribute::Builtin:
626     return bitc::ATTR_KIND_BUILTIN;
627   case Attribute::ByVal:
628     return bitc::ATTR_KIND_BY_VAL;
629   case Attribute::Convergent:
630     return bitc::ATTR_KIND_CONVERGENT;
631   case Attribute::InAlloca:
632     return bitc::ATTR_KIND_IN_ALLOCA;
633   case Attribute::Cold:
634     return bitc::ATTR_KIND_COLD;
635   case Attribute::InaccessibleMemOnly:
636     return bitc::ATTR_KIND_INACCESSIBLEMEM_ONLY;
637   case Attribute::InaccessibleMemOrArgMemOnly:
638     return bitc::ATTR_KIND_INACCESSIBLEMEM_OR_ARGMEMONLY;
639   case Attribute::InlineHint:
640     return bitc::ATTR_KIND_INLINE_HINT;
641   case Attribute::InReg:
642     return bitc::ATTR_KIND_IN_REG;
643   case Attribute::JumpTable:
644     return bitc::ATTR_KIND_JUMP_TABLE;
645   case Attribute::MinSize:
646     return bitc::ATTR_KIND_MIN_SIZE;
647   case Attribute::Naked:
648     return bitc::ATTR_KIND_NAKED;
649   case Attribute::Nest:
650     return bitc::ATTR_KIND_NEST;
651   case Attribute::NoAlias:
652     return bitc::ATTR_KIND_NO_ALIAS;
653   case Attribute::NoBuiltin:
654     return bitc::ATTR_KIND_NO_BUILTIN;
655   case Attribute::NoCapture:
656     return bitc::ATTR_KIND_NO_CAPTURE;
657   case Attribute::NoDuplicate:
658     return bitc::ATTR_KIND_NO_DUPLICATE;
659   case Attribute::NoImplicitFloat:
660     return bitc::ATTR_KIND_NO_IMPLICIT_FLOAT;
661   case Attribute::NoInline:
662     return bitc::ATTR_KIND_NO_INLINE;
663   case Attribute::NoRecurse:
664     return bitc::ATTR_KIND_NO_RECURSE;
665   case Attribute::NonLazyBind:
666     return bitc::ATTR_KIND_NON_LAZY_BIND;
667   case Attribute::NonNull:
668     return bitc::ATTR_KIND_NON_NULL;
669   case Attribute::Dereferenceable:
670     return bitc::ATTR_KIND_DEREFERENCEABLE;
671   case Attribute::DereferenceableOrNull:
672     return bitc::ATTR_KIND_DEREFERENCEABLE_OR_NULL;
673   case Attribute::NoRedZone:
674     return bitc::ATTR_KIND_NO_RED_ZONE;
675   case Attribute::NoReturn:
676     return bitc::ATTR_KIND_NO_RETURN;
677   case Attribute::NoUnwind:
678     return bitc::ATTR_KIND_NO_UNWIND;
679   case Attribute::OptimizeForSize:
680     return bitc::ATTR_KIND_OPTIMIZE_FOR_SIZE;
681   case Attribute::OptimizeNone:
682     return bitc::ATTR_KIND_OPTIMIZE_NONE;
683   case Attribute::ReadNone:
684     return bitc::ATTR_KIND_READ_NONE;
685   case Attribute::ReadOnly:
686     return bitc::ATTR_KIND_READ_ONLY;
687   case Attribute::Returned:
688     return bitc::ATTR_KIND_RETURNED;
689   case Attribute::ReturnsTwice:
690     return bitc::ATTR_KIND_RETURNS_TWICE;
691   case Attribute::SExt:
692     return bitc::ATTR_KIND_S_EXT;
693   case Attribute::StackAlignment:
694     return bitc::ATTR_KIND_STACK_ALIGNMENT;
695   case Attribute::StackProtect:
696     return bitc::ATTR_KIND_STACK_PROTECT;
697   case Attribute::StackProtectReq:
698     return bitc::ATTR_KIND_STACK_PROTECT_REQ;
699   case Attribute::StackProtectStrong:
700     return bitc::ATTR_KIND_STACK_PROTECT_STRONG;
701   case Attribute::SafeStack:
702     return bitc::ATTR_KIND_SAFESTACK;
703   case Attribute::StructRet:
704     return bitc::ATTR_KIND_STRUCT_RET;
705   case Attribute::SanitizeAddress:
706     return bitc::ATTR_KIND_SANITIZE_ADDRESS;
707   case Attribute::SanitizeThread:
708     return bitc::ATTR_KIND_SANITIZE_THREAD;
709   case Attribute::SanitizeMemory:
710     return bitc::ATTR_KIND_SANITIZE_MEMORY;
711   case Attribute::SwiftError:
712     return bitc::ATTR_KIND_SWIFT_ERROR;
713   case Attribute::SwiftSelf:
714     return bitc::ATTR_KIND_SWIFT_SELF;
715   case Attribute::UWTable:
716     return bitc::ATTR_KIND_UW_TABLE;
717   case Attribute::WriteOnly:
718     return bitc::ATTR_KIND_WRITEONLY;
719   case Attribute::ZExt:
720     return bitc::ATTR_KIND_Z_EXT;
721   case Attribute::EndAttrKinds:
722     llvm_unreachable("Can not encode end-attribute kinds marker.");
723   case Attribute::None:
724     llvm_unreachable("Can not encode none-attribute.");
725   }
726 
727   llvm_unreachable("Trying to encode unknown attribute");
728 }
729 
730 void ModuleBitcodeWriter::writeAttributeGroupTable() {
731   const std::vector<AttributeSet> &AttrGrps = VE.getAttributeGroups();
732   if (AttrGrps.empty()) return;
733 
734   Stream.EnterSubblock(bitc::PARAMATTR_GROUP_BLOCK_ID, 3);
735 
736   SmallVector<uint64_t, 64> Record;
737   for (unsigned i = 0, e = AttrGrps.size(); i != e; ++i) {
738     AttributeSet AS = AttrGrps[i];
739     for (unsigned i = 0, e = AS.getNumSlots(); i != e; ++i) {
740       AttributeSet A = AS.getSlotAttributes(i);
741 
742       Record.push_back(VE.getAttributeGroupID(A));
743       Record.push_back(AS.getSlotIndex(i));
744 
745       for (AttributeSet::iterator I = AS.begin(0), E = AS.end(0);
746            I != E; ++I) {
747         Attribute Attr = *I;
748         if (Attr.isEnumAttribute()) {
749           Record.push_back(0);
750           Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
751         } else if (Attr.isIntAttribute()) {
752           Record.push_back(1);
753           Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
754           Record.push_back(Attr.getValueAsInt());
755         } else {
756           StringRef Kind = Attr.getKindAsString();
757           StringRef Val = Attr.getValueAsString();
758 
759           Record.push_back(Val.empty() ? 3 : 4);
760           Record.append(Kind.begin(), Kind.end());
761           Record.push_back(0);
762           if (!Val.empty()) {
763             Record.append(Val.begin(), Val.end());
764             Record.push_back(0);
765           }
766         }
767       }
768 
769       Stream.EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
770       Record.clear();
771     }
772   }
773 
774   Stream.ExitBlock();
775 }
776 
777 void ModuleBitcodeWriter::writeAttributeTable() {
778   const std::vector<AttributeSet> &Attrs = VE.getAttributes();
779   if (Attrs.empty()) return;
780 
781   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
782 
783   SmallVector<uint64_t, 64> Record;
784   for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
785     const AttributeSet &A = Attrs[i];
786     for (unsigned i = 0, e = A.getNumSlots(); i != e; ++i)
787       Record.push_back(VE.getAttributeGroupID(A.getSlotAttributes(i)));
788 
789     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
790     Record.clear();
791   }
792 
793   Stream.ExitBlock();
794 }
795 
796 /// WriteTypeTable - Write out the type table for a module.
797 void ModuleBitcodeWriter::writeTypeTable() {
798   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
799 
800   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
801   SmallVector<uint64_t, 64> TypeVals;
802 
803   uint64_t NumBits = VE.computeBitsRequiredForTypeIndicies();
804 
805   // Abbrev for TYPE_CODE_POINTER.
806   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
807   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
808   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
809   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
810   unsigned PtrAbbrev = Stream.EmitAbbrev(Abbv);
811 
812   // Abbrev for TYPE_CODE_FUNCTION.
813   Abbv = new BitCodeAbbrev();
814   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
815   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
816   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
817   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
818 
819   unsigned FunctionAbbrev = Stream.EmitAbbrev(Abbv);
820 
821   // Abbrev for TYPE_CODE_STRUCT_ANON.
822   Abbv = new BitCodeAbbrev();
823   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
824   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
825   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
826   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
827 
828   unsigned StructAnonAbbrev = Stream.EmitAbbrev(Abbv);
829 
830   // Abbrev for TYPE_CODE_STRUCT_NAME.
831   Abbv = new BitCodeAbbrev();
832   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
833   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
834   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
835   unsigned StructNameAbbrev = Stream.EmitAbbrev(Abbv);
836 
837   // Abbrev for TYPE_CODE_STRUCT_NAMED.
838   Abbv = new BitCodeAbbrev();
839   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
840   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
841   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
842   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
843 
844   unsigned StructNamedAbbrev = Stream.EmitAbbrev(Abbv);
845 
846   // Abbrev for TYPE_CODE_ARRAY.
847   Abbv = new BitCodeAbbrev();
848   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
849   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
850   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
851 
852   unsigned ArrayAbbrev = Stream.EmitAbbrev(Abbv);
853 
854   // Emit an entry count so the reader can reserve space.
855   TypeVals.push_back(TypeList.size());
856   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
857   TypeVals.clear();
858 
859   // Loop over all of the types, emitting each in turn.
860   for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
861     Type *T = TypeList[i];
862     int AbbrevToUse = 0;
863     unsigned Code = 0;
864 
865     switch (T->getTypeID()) {
866     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;      break;
867     case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;      break;
868     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;     break;
869     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE;    break;
870     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80;  break;
871     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128;     break;
872     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
873     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;     break;
874     case Type::MetadataTyID:  Code = bitc::TYPE_CODE_METADATA;  break;
875     case Type::X86_MMXTyID:   Code = bitc::TYPE_CODE_X86_MMX;   break;
876     case Type::TokenTyID:     Code = bitc::TYPE_CODE_TOKEN;     break;
877     case Type::IntegerTyID:
878       // INTEGER: [width]
879       Code = bitc::TYPE_CODE_INTEGER;
880       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
881       break;
882     case Type::PointerTyID: {
883       PointerType *PTy = cast<PointerType>(T);
884       // POINTER: [pointee type, address space]
885       Code = bitc::TYPE_CODE_POINTER;
886       TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
887       unsigned AddressSpace = PTy->getAddressSpace();
888       TypeVals.push_back(AddressSpace);
889       if (AddressSpace == 0) AbbrevToUse = PtrAbbrev;
890       break;
891     }
892     case Type::FunctionTyID: {
893       FunctionType *FT = cast<FunctionType>(T);
894       // FUNCTION: [isvararg, retty, paramty x N]
895       Code = bitc::TYPE_CODE_FUNCTION;
896       TypeVals.push_back(FT->isVarArg());
897       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
898       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
899         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
900       AbbrevToUse = FunctionAbbrev;
901       break;
902     }
903     case Type::StructTyID: {
904       StructType *ST = cast<StructType>(T);
905       // STRUCT: [ispacked, eltty x N]
906       TypeVals.push_back(ST->isPacked());
907       // Output all of the element types.
908       for (StructType::element_iterator I = ST->element_begin(),
909            E = ST->element_end(); I != E; ++I)
910         TypeVals.push_back(VE.getTypeID(*I));
911 
912       if (ST->isLiteral()) {
913         Code = bitc::TYPE_CODE_STRUCT_ANON;
914         AbbrevToUse = StructAnonAbbrev;
915       } else {
916         if (ST->isOpaque()) {
917           Code = bitc::TYPE_CODE_OPAQUE;
918         } else {
919           Code = bitc::TYPE_CODE_STRUCT_NAMED;
920           AbbrevToUse = StructNamedAbbrev;
921         }
922 
923         // Emit the name if it is present.
924         if (!ST->getName().empty())
925           writeStringRecord(bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
926                             StructNameAbbrev);
927       }
928       break;
929     }
930     case Type::ArrayTyID: {
931       ArrayType *AT = cast<ArrayType>(T);
932       // ARRAY: [numelts, eltty]
933       Code = bitc::TYPE_CODE_ARRAY;
934       TypeVals.push_back(AT->getNumElements());
935       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
936       AbbrevToUse = ArrayAbbrev;
937       break;
938     }
939     case Type::VectorTyID: {
940       VectorType *VT = cast<VectorType>(T);
941       // VECTOR [numelts, eltty]
942       Code = bitc::TYPE_CODE_VECTOR;
943       TypeVals.push_back(VT->getNumElements());
944       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
945       break;
946     }
947     }
948 
949     // Emit the finished record.
950     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
951     TypeVals.clear();
952   }
953 
954   Stream.ExitBlock();
955 }
956 
957 static unsigned getEncodedLinkage(const GlobalValue::LinkageTypes Linkage) {
958   switch (Linkage) {
959   case GlobalValue::ExternalLinkage:
960     return 0;
961   case GlobalValue::WeakAnyLinkage:
962     return 16;
963   case GlobalValue::AppendingLinkage:
964     return 2;
965   case GlobalValue::InternalLinkage:
966     return 3;
967   case GlobalValue::LinkOnceAnyLinkage:
968     return 18;
969   case GlobalValue::ExternalWeakLinkage:
970     return 7;
971   case GlobalValue::CommonLinkage:
972     return 8;
973   case GlobalValue::PrivateLinkage:
974     return 9;
975   case GlobalValue::WeakODRLinkage:
976     return 17;
977   case GlobalValue::LinkOnceODRLinkage:
978     return 19;
979   case GlobalValue::AvailableExternallyLinkage:
980     return 12;
981   }
982   llvm_unreachable("Invalid linkage");
983 }
984 
985 static unsigned getEncodedLinkage(const GlobalValue &GV) {
986   return getEncodedLinkage(GV.getLinkage());
987 }
988 
989 // Decode the flags for GlobalValue in the summary
990 static uint64_t getEncodedGVSummaryFlags(GlobalValueSummary::GVFlags Flags) {
991   uint64_t RawFlags = 0;
992 
993   RawFlags |= Flags.NoRename; // bool
994   RawFlags |= (Flags.IsNotViableToInline << 1);
995   RawFlags |= (Flags.HasInlineAsmMaybeReferencingInternal << 2);
996   // Linkage don't need to be remapped at that time for the summary. Any future
997   // change to the getEncodedLinkage() function will need to be taken into
998   // account here as well.
999   RawFlags = (RawFlags << 4) | Flags.Linkage; // 4 bits
1000 
1001   return RawFlags;
1002 }
1003 
1004 static unsigned getEncodedVisibility(const GlobalValue &GV) {
1005   switch (GV.getVisibility()) {
1006   case GlobalValue::DefaultVisibility:   return 0;
1007   case GlobalValue::HiddenVisibility:    return 1;
1008   case GlobalValue::ProtectedVisibility: return 2;
1009   }
1010   llvm_unreachable("Invalid visibility");
1011 }
1012 
1013 static unsigned getEncodedDLLStorageClass(const GlobalValue &GV) {
1014   switch (GV.getDLLStorageClass()) {
1015   case GlobalValue::DefaultStorageClass:   return 0;
1016   case GlobalValue::DLLImportStorageClass: return 1;
1017   case GlobalValue::DLLExportStorageClass: return 2;
1018   }
1019   llvm_unreachable("Invalid DLL storage class");
1020 }
1021 
1022 static unsigned getEncodedThreadLocalMode(const GlobalValue &GV) {
1023   switch (GV.getThreadLocalMode()) {
1024     case GlobalVariable::NotThreadLocal:         return 0;
1025     case GlobalVariable::GeneralDynamicTLSModel: return 1;
1026     case GlobalVariable::LocalDynamicTLSModel:   return 2;
1027     case GlobalVariable::InitialExecTLSModel:    return 3;
1028     case GlobalVariable::LocalExecTLSModel:      return 4;
1029   }
1030   llvm_unreachable("Invalid TLS model");
1031 }
1032 
1033 static unsigned getEncodedComdatSelectionKind(const Comdat &C) {
1034   switch (C.getSelectionKind()) {
1035   case Comdat::Any:
1036     return bitc::COMDAT_SELECTION_KIND_ANY;
1037   case Comdat::ExactMatch:
1038     return bitc::COMDAT_SELECTION_KIND_EXACT_MATCH;
1039   case Comdat::Largest:
1040     return bitc::COMDAT_SELECTION_KIND_LARGEST;
1041   case Comdat::NoDuplicates:
1042     return bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES;
1043   case Comdat::SameSize:
1044     return bitc::COMDAT_SELECTION_KIND_SAME_SIZE;
1045   }
1046   llvm_unreachable("Invalid selection kind");
1047 }
1048 
1049 static unsigned getEncodedUnnamedAddr(const GlobalValue &GV) {
1050   switch (GV.getUnnamedAddr()) {
1051   case GlobalValue::UnnamedAddr::None:   return 0;
1052   case GlobalValue::UnnamedAddr::Local:  return 2;
1053   case GlobalValue::UnnamedAddr::Global: return 1;
1054   }
1055   llvm_unreachable("Invalid unnamed_addr");
1056 }
1057 
1058 void ModuleBitcodeWriter::writeComdats() {
1059   SmallVector<unsigned, 64> Vals;
1060   for (const Comdat *C : VE.getComdats()) {
1061     // COMDAT: [selection_kind, name]
1062     Vals.push_back(getEncodedComdatSelectionKind(*C));
1063     size_t Size = C->getName().size();
1064     assert(isUInt<32>(Size));
1065     Vals.push_back(Size);
1066     for (char Chr : C->getName())
1067       Vals.push_back((unsigned char)Chr);
1068     Stream.EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
1069     Vals.clear();
1070   }
1071 }
1072 
1073 /// Write a record that will eventually hold the word offset of the
1074 /// module-level VST. For now the offset is 0, which will be backpatched
1075 /// after the real VST is written. Saves the bit offset to backpatch.
1076 void BitcodeWriter::writeValueSymbolTableForwardDecl() {
1077   // Write a placeholder value in for the offset of the real VST,
1078   // which is written after the function blocks so that it can include
1079   // the offset of each function. The placeholder offset will be
1080   // updated when the real VST is written.
1081   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1082   Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_VSTOFFSET));
1083   // Blocks are 32-bit aligned, so we can use a 32-bit word offset to
1084   // hold the real VST offset. Must use fixed instead of VBR as we don't
1085   // know how many VBR chunks to reserve ahead of time.
1086   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
1087   unsigned VSTOffsetAbbrev = Stream.EmitAbbrev(Abbv);
1088 
1089   // Emit the placeholder
1090   uint64_t Vals[] = {bitc::MODULE_CODE_VSTOFFSET, 0};
1091   Stream.EmitRecordWithAbbrev(VSTOffsetAbbrev, Vals);
1092 
1093   // Compute and save the bit offset to the placeholder, which will be
1094   // patched when the real VST is written. We can simply subtract the 32-bit
1095   // fixed size from the current bit number to get the location to backpatch.
1096   VSTOffsetPlaceholder = Stream.GetCurrentBitNo() - 32;
1097 }
1098 
1099 enum StringEncoding { SE_Char6, SE_Fixed7, SE_Fixed8 };
1100 
1101 /// Determine the encoding to use for the given string name and length.
1102 static StringEncoding getStringEncoding(const char *Str, unsigned StrLen) {
1103   bool isChar6 = true;
1104   for (const char *C = Str, *E = C + StrLen; C != E; ++C) {
1105     if (isChar6)
1106       isChar6 = BitCodeAbbrevOp::isChar6(*C);
1107     if ((unsigned char)*C & 128)
1108       // don't bother scanning the rest.
1109       return SE_Fixed8;
1110   }
1111   if (isChar6)
1112     return SE_Char6;
1113   else
1114     return SE_Fixed7;
1115 }
1116 
1117 /// Emit top-level description of module, including target triple, inline asm,
1118 /// descriptors for global variables, and function prototype info.
1119 /// Returns the bit offset to backpatch with the location of the real VST.
1120 void ModuleBitcodeWriter::writeModuleInfo() {
1121   // Emit various pieces of data attached to a module.
1122   if (!M.getTargetTriple().empty())
1123     writeStringRecord(bitc::MODULE_CODE_TRIPLE, M.getTargetTriple(),
1124                       0 /*TODO*/);
1125   const std::string &DL = M.getDataLayoutStr();
1126   if (!DL.empty())
1127     writeStringRecord(bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/);
1128   if (!M.getModuleInlineAsm().empty())
1129     writeStringRecord(bitc::MODULE_CODE_ASM, M.getModuleInlineAsm(),
1130                       0 /*TODO*/);
1131 
1132   // Emit information about sections and GC, computing how many there are. Also
1133   // compute the maximum alignment value.
1134   std::map<std::string, unsigned> SectionMap;
1135   std::map<std::string, unsigned> GCMap;
1136   unsigned MaxAlignment = 0;
1137   unsigned MaxGlobalType = 0;
1138   for (const GlobalValue &GV : M.globals()) {
1139     MaxAlignment = std::max(MaxAlignment, GV.getAlignment());
1140     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getValueType()));
1141     if (GV.hasSection()) {
1142       // Give section names unique ID's.
1143       unsigned &Entry = SectionMap[GV.getSection()];
1144       if (!Entry) {
1145         writeStringRecord(bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
1146                           0 /*TODO*/);
1147         Entry = SectionMap.size();
1148       }
1149     }
1150   }
1151   for (const Function &F : M) {
1152     MaxAlignment = std::max(MaxAlignment, F.getAlignment());
1153     if (F.hasSection()) {
1154       // Give section names unique ID's.
1155       unsigned &Entry = SectionMap[F.getSection()];
1156       if (!Entry) {
1157         writeStringRecord(bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
1158                           0 /*TODO*/);
1159         Entry = SectionMap.size();
1160       }
1161     }
1162     if (F.hasGC()) {
1163       // Same for GC names.
1164       unsigned &Entry = GCMap[F.getGC()];
1165       if (!Entry) {
1166         writeStringRecord(bitc::MODULE_CODE_GCNAME, F.getGC(), 0 /*TODO*/);
1167         Entry = GCMap.size();
1168       }
1169     }
1170   }
1171 
1172   // Emit abbrev for globals, now that we know # sections and max alignment.
1173   unsigned SimpleGVarAbbrev = 0;
1174   if (!M.global_empty()) {
1175     // Add an abbrev for common globals with no visibility or thread localness.
1176     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1177     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
1178     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1179                               Log2_32_Ceil(MaxGlobalType+1)));
1180     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddrSpace << 2
1181                                                            //| explicitType << 1
1182                                                            //| constant
1183     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Initializer.
1184     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // Linkage.
1185     if (MaxAlignment == 0)                                 // Alignment.
1186       Abbv->Add(BitCodeAbbrevOp(0));
1187     else {
1188       unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
1189       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1190                                Log2_32_Ceil(MaxEncAlignment+1)));
1191     }
1192     if (SectionMap.empty())                                    // Section.
1193       Abbv->Add(BitCodeAbbrevOp(0));
1194     else
1195       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1196                                Log2_32_Ceil(SectionMap.size()+1)));
1197     // Don't bother emitting vis + thread local.
1198     SimpleGVarAbbrev = Stream.EmitAbbrev(Abbv);
1199   }
1200 
1201   // Emit the global variable information.
1202   SmallVector<unsigned, 64> Vals;
1203   for (const GlobalVariable &GV : M.globals()) {
1204     unsigned AbbrevToUse = 0;
1205 
1206     // GLOBALVAR: [type, isconst, initid,
1207     //             linkage, alignment, section, visibility, threadlocal,
1208     //             unnamed_addr, externally_initialized, dllstorageclass,
1209     //             comdat]
1210     Vals.push_back(VE.getTypeID(GV.getValueType()));
1211     Vals.push_back(GV.getType()->getAddressSpace() << 2 | 2 | GV.isConstant());
1212     Vals.push_back(GV.isDeclaration() ? 0 :
1213                    (VE.getValueID(GV.getInitializer()) + 1));
1214     Vals.push_back(getEncodedLinkage(GV));
1215     Vals.push_back(Log2_32(GV.getAlignment())+1);
1216     Vals.push_back(GV.hasSection() ? SectionMap[GV.getSection()] : 0);
1217     if (GV.isThreadLocal() ||
1218         GV.getVisibility() != GlobalValue::DefaultVisibility ||
1219         GV.getUnnamedAddr() != GlobalValue::UnnamedAddr::None ||
1220         GV.isExternallyInitialized() ||
1221         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
1222         GV.hasComdat()) {
1223       Vals.push_back(getEncodedVisibility(GV));
1224       Vals.push_back(getEncodedThreadLocalMode(GV));
1225       Vals.push_back(getEncodedUnnamedAddr(GV));
1226       Vals.push_back(GV.isExternallyInitialized());
1227       Vals.push_back(getEncodedDLLStorageClass(GV));
1228       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
1229     } else {
1230       AbbrevToUse = SimpleGVarAbbrev;
1231     }
1232 
1233     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
1234     Vals.clear();
1235   }
1236 
1237   // Emit the function proto information.
1238   for (const Function &F : M) {
1239     // FUNCTION:  [type, callingconv, isproto, linkage, paramattrs, alignment,
1240     //             section, visibility, gc, unnamed_addr, prologuedata,
1241     //             dllstorageclass, comdat, prefixdata, personalityfn]
1242     Vals.push_back(VE.getTypeID(F.getFunctionType()));
1243     Vals.push_back(F.getCallingConv());
1244     Vals.push_back(F.isDeclaration());
1245     Vals.push_back(getEncodedLinkage(F));
1246     Vals.push_back(VE.getAttributeID(F.getAttributes()));
1247     Vals.push_back(Log2_32(F.getAlignment())+1);
1248     Vals.push_back(F.hasSection() ? SectionMap[F.getSection()] : 0);
1249     Vals.push_back(getEncodedVisibility(F));
1250     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
1251     Vals.push_back(getEncodedUnnamedAddr(F));
1252     Vals.push_back(F.hasPrologueData() ? (VE.getValueID(F.getPrologueData()) + 1)
1253                                        : 0);
1254     Vals.push_back(getEncodedDLLStorageClass(F));
1255     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
1256     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
1257                                      : 0);
1258     Vals.push_back(
1259         F.hasPersonalityFn() ? (VE.getValueID(F.getPersonalityFn()) + 1) : 0);
1260 
1261     unsigned AbbrevToUse = 0;
1262     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
1263     Vals.clear();
1264   }
1265 
1266   // Emit the alias information.
1267   for (const GlobalAlias &A : M.aliases()) {
1268     // ALIAS: [alias type, aliasee val#, linkage, visibility, dllstorageclass,
1269     //         threadlocal, unnamed_addr]
1270     Vals.push_back(VE.getTypeID(A.getValueType()));
1271     Vals.push_back(A.getType()->getAddressSpace());
1272     Vals.push_back(VE.getValueID(A.getAliasee()));
1273     Vals.push_back(getEncodedLinkage(A));
1274     Vals.push_back(getEncodedVisibility(A));
1275     Vals.push_back(getEncodedDLLStorageClass(A));
1276     Vals.push_back(getEncodedThreadLocalMode(A));
1277     Vals.push_back(getEncodedUnnamedAddr(A));
1278     unsigned AbbrevToUse = 0;
1279     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
1280     Vals.clear();
1281   }
1282 
1283   // Emit the ifunc information.
1284   for (const GlobalIFunc &I : M.ifuncs()) {
1285     // IFUNC: [ifunc type, address space, resolver val#, linkage, visibility]
1286     Vals.push_back(VE.getTypeID(I.getValueType()));
1287     Vals.push_back(I.getType()->getAddressSpace());
1288     Vals.push_back(VE.getValueID(I.getResolver()));
1289     Vals.push_back(getEncodedLinkage(I));
1290     Vals.push_back(getEncodedVisibility(I));
1291     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
1292     Vals.clear();
1293   }
1294 
1295   // Emit the module's source file name.
1296   {
1297     StringEncoding Bits = getStringEncoding(M.getSourceFileName().data(),
1298                                             M.getSourceFileName().size());
1299     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
1300     if (Bits == SE_Char6)
1301       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
1302     else if (Bits == SE_Fixed7)
1303       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
1304 
1305     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
1306     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1307     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
1308     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1309     Abbv->Add(AbbrevOpToUse);
1310     unsigned FilenameAbbrev = Stream.EmitAbbrev(Abbv);
1311 
1312     for (const auto P : M.getSourceFileName())
1313       Vals.push_back((unsigned char)P);
1314 
1315     // Emit the finished record.
1316     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
1317     Vals.clear();
1318   }
1319 
1320   // If we have a VST, write the VSTOFFSET record placeholder.
1321   if (M.getValueSymbolTable().empty())
1322     return;
1323   writeValueSymbolTableForwardDecl();
1324 }
1325 
1326 static uint64_t getOptimizationFlags(const Value *V) {
1327   uint64_t Flags = 0;
1328 
1329   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
1330     if (OBO->hasNoSignedWrap())
1331       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
1332     if (OBO->hasNoUnsignedWrap())
1333       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
1334   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
1335     if (PEO->isExact())
1336       Flags |= 1 << bitc::PEO_EXACT;
1337   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
1338     if (FPMO->hasUnsafeAlgebra())
1339       Flags |= FastMathFlags::UnsafeAlgebra;
1340     if (FPMO->hasNoNaNs())
1341       Flags |= FastMathFlags::NoNaNs;
1342     if (FPMO->hasNoInfs())
1343       Flags |= FastMathFlags::NoInfs;
1344     if (FPMO->hasNoSignedZeros())
1345       Flags |= FastMathFlags::NoSignedZeros;
1346     if (FPMO->hasAllowReciprocal())
1347       Flags |= FastMathFlags::AllowReciprocal;
1348   }
1349 
1350   return Flags;
1351 }
1352 
1353 void ModuleBitcodeWriter::writeValueAsMetadata(
1354     const ValueAsMetadata *MD, SmallVectorImpl<uint64_t> &Record) {
1355   // Mimic an MDNode with a value as one operand.
1356   Value *V = MD->getValue();
1357   Record.push_back(VE.getTypeID(V->getType()));
1358   Record.push_back(VE.getValueID(V));
1359   Stream.EmitRecord(bitc::METADATA_VALUE, Record, 0);
1360   Record.clear();
1361 }
1362 
1363 void ModuleBitcodeWriter::writeMDTuple(const MDTuple *N,
1364                                        SmallVectorImpl<uint64_t> &Record,
1365                                        unsigned Abbrev) {
1366   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
1367     Metadata *MD = N->getOperand(i);
1368     assert(!(MD && isa<LocalAsMetadata>(MD)) &&
1369            "Unexpected function-local metadata");
1370     Record.push_back(VE.getMetadataOrNullID(MD));
1371   }
1372   Stream.EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
1373                                     : bitc::METADATA_NODE,
1374                     Record, Abbrev);
1375   Record.clear();
1376 }
1377 
1378 unsigned ModuleBitcodeWriter::createDILocationAbbrev() {
1379   // Assume the column is usually under 128, and always output the inlined-at
1380   // location (it's never more expensive than building an array size 1).
1381   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1382   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
1383   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1384   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1385   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1386   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1387   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1388   return Stream.EmitAbbrev(Abbv);
1389 }
1390 
1391 void ModuleBitcodeWriter::writeDILocation(const DILocation *N,
1392                                           SmallVectorImpl<uint64_t> &Record,
1393                                           unsigned &Abbrev) {
1394   if (!Abbrev)
1395     Abbrev = createDILocationAbbrev();
1396 
1397   Record.push_back(N->isDistinct());
1398   Record.push_back(N->getLine());
1399   Record.push_back(N->getColumn());
1400   Record.push_back(VE.getMetadataID(N->getScope()));
1401   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
1402 
1403   Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
1404   Record.clear();
1405 }
1406 
1407 unsigned ModuleBitcodeWriter::createGenericDINodeAbbrev() {
1408   // Assume the column is usually under 128, and always output the inlined-at
1409   // location (it's never more expensive than building an array size 1).
1410   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1411   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
1412   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1413   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1414   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1415   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1416   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1417   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1418   return Stream.EmitAbbrev(Abbv);
1419 }
1420 
1421 void ModuleBitcodeWriter::writeGenericDINode(const GenericDINode *N,
1422                                              SmallVectorImpl<uint64_t> &Record,
1423                                              unsigned &Abbrev) {
1424   if (!Abbrev)
1425     Abbrev = createGenericDINodeAbbrev();
1426 
1427   Record.push_back(N->isDistinct());
1428   Record.push_back(N->getTag());
1429   Record.push_back(0); // Per-tag version field; unused for now.
1430 
1431   for (auto &I : N->operands())
1432     Record.push_back(VE.getMetadataOrNullID(I));
1433 
1434   Stream.EmitRecord(bitc::METADATA_GENERIC_DEBUG, Record, Abbrev);
1435   Record.clear();
1436 }
1437 
1438 static uint64_t rotateSign(int64_t I) {
1439   uint64_t U = I;
1440   return I < 0 ? ~(U << 1) : U << 1;
1441 }
1442 
1443 void ModuleBitcodeWriter::writeDISubrange(const DISubrange *N,
1444                                           SmallVectorImpl<uint64_t> &Record,
1445                                           unsigned Abbrev) {
1446   Record.push_back(N->isDistinct());
1447   Record.push_back(N->getCount());
1448   Record.push_back(rotateSign(N->getLowerBound()));
1449 
1450   Stream.EmitRecord(bitc::METADATA_SUBRANGE, Record, Abbrev);
1451   Record.clear();
1452 }
1453 
1454 void ModuleBitcodeWriter::writeDIEnumerator(const DIEnumerator *N,
1455                                             SmallVectorImpl<uint64_t> &Record,
1456                                             unsigned Abbrev) {
1457   Record.push_back(N->isDistinct());
1458   Record.push_back(rotateSign(N->getValue()));
1459   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1460 
1461   Stream.EmitRecord(bitc::METADATA_ENUMERATOR, Record, Abbrev);
1462   Record.clear();
1463 }
1464 
1465 void ModuleBitcodeWriter::writeDIBasicType(const DIBasicType *N,
1466                                            SmallVectorImpl<uint64_t> &Record,
1467                                            unsigned Abbrev) {
1468   Record.push_back(N->isDistinct());
1469   Record.push_back(N->getTag());
1470   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1471   Record.push_back(N->getSizeInBits());
1472   Record.push_back(N->getAlignInBits());
1473   Record.push_back(N->getEncoding());
1474 
1475   Stream.EmitRecord(bitc::METADATA_BASIC_TYPE, Record, Abbrev);
1476   Record.clear();
1477 }
1478 
1479 void ModuleBitcodeWriter::writeDIDerivedType(const DIDerivedType *N,
1480                                              SmallVectorImpl<uint64_t> &Record,
1481                                              unsigned Abbrev) {
1482   Record.push_back(N->isDistinct());
1483   Record.push_back(N->getTag());
1484   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1485   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1486   Record.push_back(N->getLine());
1487   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1488   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1489   Record.push_back(N->getSizeInBits());
1490   Record.push_back(N->getAlignInBits());
1491   Record.push_back(N->getOffsetInBits());
1492   Record.push_back(N->getFlags());
1493   Record.push_back(VE.getMetadataOrNullID(N->getExtraData()));
1494 
1495   Stream.EmitRecord(bitc::METADATA_DERIVED_TYPE, Record, Abbrev);
1496   Record.clear();
1497 }
1498 
1499 void ModuleBitcodeWriter::writeDICompositeType(
1500     const DICompositeType *N, SmallVectorImpl<uint64_t> &Record,
1501     unsigned Abbrev) {
1502   const unsigned IsNotUsedInOldTypeRef = 0x2;
1503   Record.push_back(IsNotUsedInOldTypeRef | (unsigned)N->isDistinct());
1504   Record.push_back(N->getTag());
1505   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1506   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1507   Record.push_back(N->getLine());
1508   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1509   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1510   Record.push_back(N->getSizeInBits());
1511   Record.push_back(N->getAlignInBits());
1512   Record.push_back(N->getOffsetInBits());
1513   Record.push_back(N->getFlags());
1514   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1515   Record.push_back(N->getRuntimeLang());
1516   Record.push_back(VE.getMetadataOrNullID(N->getVTableHolder()));
1517   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1518   Record.push_back(VE.getMetadataOrNullID(N->getRawIdentifier()));
1519 
1520   Stream.EmitRecord(bitc::METADATA_COMPOSITE_TYPE, Record, Abbrev);
1521   Record.clear();
1522 }
1523 
1524 void ModuleBitcodeWriter::writeDISubroutineType(
1525     const DISubroutineType *N, SmallVectorImpl<uint64_t> &Record,
1526     unsigned Abbrev) {
1527   const unsigned HasNoOldTypeRefs = 0x2;
1528   Record.push_back(HasNoOldTypeRefs | (unsigned)N->isDistinct());
1529   Record.push_back(N->getFlags());
1530   Record.push_back(VE.getMetadataOrNullID(N->getTypeArray().get()));
1531   Record.push_back(N->getCC());
1532 
1533   Stream.EmitRecord(bitc::METADATA_SUBROUTINE_TYPE, Record, Abbrev);
1534   Record.clear();
1535 }
1536 
1537 void ModuleBitcodeWriter::writeDIFile(const DIFile *N,
1538                                       SmallVectorImpl<uint64_t> &Record,
1539                                       unsigned Abbrev) {
1540   Record.push_back(N->isDistinct());
1541   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
1542   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
1543 
1544   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
1545   Record.clear();
1546 }
1547 
1548 void ModuleBitcodeWriter::writeDICompileUnit(const DICompileUnit *N,
1549                                              SmallVectorImpl<uint64_t> &Record,
1550                                              unsigned Abbrev) {
1551   assert(N->isDistinct() && "Expected distinct compile units");
1552   Record.push_back(/* IsDistinct */ true);
1553   Record.push_back(N->getSourceLanguage());
1554   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1555   Record.push_back(VE.getMetadataOrNullID(N->getRawProducer()));
1556   Record.push_back(N->isOptimized());
1557   Record.push_back(VE.getMetadataOrNullID(N->getRawFlags()));
1558   Record.push_back(N->getRuntimeVersion());
1559   Record.push_back(VE.getMetadataOrNullID(N->getRawSplitDebugFilename()));
1560   Record.push_back(N->getEmissionKind());
1561   Record.push_back(VE.getMetadataOrNullID(N->getEnumTypes().get()));
1562   Record.push_back(VE.getMetadataOrNullID(N->getRetainedTypes().get()));
1563   Record.push_back(/* subprograms */ 0);
1564   Record.push_back(VE.getMetadataOrNullID(N->getGlobalVariables().get()));
1565   Record.push_back(VE.getMetadataOrNullID(N->getImportedEntities().get()));
1566   Record.push_back(N->getDWOId());
1567   Record.push_back(VE.getMetadataOrNullID(N->getMacros().get()));
1568   Record.push_back(N->getSplitDebugInlining());
1569 
1570   Stream.EmitRecord(bitc::METADATA_COMPILE_UNIT, Record, Abbrev);
1571   Record.clear();
1572 }
1573 
1574 void ModuleBitcodeWriter::writeDISubprogram(const DISubprogram *N,
1575                                             SmallVectorImpl<uint64_t> &Record,
1576                                             unsigned Abbrev) {
1577   uint64_t HasUnitFlag = 1 << 1;
1578   Record.push_back(N->isDistinct() | HasUnitFlag);
1579   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1580   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1581   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1582   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1583   Record.push_back(N->getLine());
1584   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1585   Record.push_back(N->isLocalToUnit());
1586   Record.push_back(N->isDefinition());
1587   Record.push_back(N->getScopeLine());
1588   Record.push_back(VE.getMetadataOrNullID(N->getContainingType()));
1589   Record.push_back(N->getVirtuality());
1590   Record.push_back(N->getVirtualIndex());
1591   Record.push_back(N->getFlags());
1592   Record.push_back(N->isOptimized());
1593   Record.push_back(VE.getMetadataOrNullID(N->getRawUnit()));
1594   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1595   Record.push_back(VE.getMetadataOrNullID(N->getDeclaration()));
1596   Record.push_back(VE.getMetadataOrNullID(N->getVariables().get()));
1597   Record.push_back(N->getThisAdjustment());
1598 
1599   Stream.EmitRecord(bitc::METADATA_SUBPROGRAM, Record, Abbrev);
1600   Record.clear();
1601 }
1602 
1603 void ModuleBitcodeWriter::writeDILexicalBlock(const DILexicalBlock *N,
1604                                               SmallVectorImpl<uint64_t> &Record,
1605                                               unsigned Abbrev) {
1606   Record.push_back(N->isDistinct());
1607   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1608   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1609   Record.push_back(N->getLine());
1610   Record.push_back(N->getColumn());
1611 
1612   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK, Record, Abbrev);
1613   Record.clear();
1614 }
1615 
1616 void ModuleBitcodeWriter::writeDILexicalBlockFile(
1617     const DILexicalBlockFile *N, SmallVectorImpl<uint64_t> &Record,
1618     unsigned Abbrev) {
1619   Record.push_back(N->isDistinct());
1620   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1621   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1622   Record.push_back(N->getDiscriminator());
1623 
1624   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK_FILE, Record, Abbrev);
1625   Record.clear();
1626 }
1627 
1628 void ModuleBitcodeWriter::writeDINamespace(const DINamespace *N,
1629                                            SmallVectorImpl<uint64_t> &Record,
1630                                            unsigned Abbrev) {
1631   Record.push_back(N->isDistinct() | N->getExportSymbols() << 1);
1632   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1633   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1634   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1635   Record.push_back(N->getLine());
1636 
1637   Stream.EmitRecord(bitc::METADATA_NAMESPACE, Record, Abbrev);
1638   Record.clear();
1639 }
1640 
1641 void ModuleBitcodeWriter::writeDIMacro(const DIMacro *N,
1642                                        SmallVectorImpl<uint64_t> &Record,
1643                                        unsigned Abbrev) {
1644   Record.push_back(N->isDistinct());
1645   Record.push_back(N->getMacinfoType());
1646   Record.push_back(N->getLine());
1647   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1648   Record.push_back(VE.getMetadataOrNullID(N->getRawValue()));
1649 
1650   Stream.EmitRecord(bitc::METADATA_MACRO, Record, Abbrev);
1651   Record.clear();
1652 }
1653 
1654 void ModuleBitcodeWriter::writeDIMacroFile(const DIMacroFile *N,
1655                                            SmallVectorImpl<uint64_t> &Record,
1656                                            unsigned Abbrev) {
1657   Record.push_back(N->isDistinct());
1658   Record.push_back(N->getMacinfoType());
1659   Record.push_back(N->getLine());
1660   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1661   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1662 
1663   Stream.EmitRecord(bitc::METADATA_MACRO_FILE, Record, Abbrev);
1664   Record.clear();
1665 }
1666 
1667 void ModuleBitcodeWriter::writeDIModule(const DIModule *N,
1668                                         SmallVectorImpl<uint64_t> &Record,
1669                                         unsigned Abbrev) {
1670   Record.push_back(N->isDistinct());
1671   for (auto &I : N->operands())
1672     Record.push_back(VE.getMetadataOrNullID(I));
1673 
1674   Stream.EmitRecord(bitc::METADATA_MODULE, Record, Abbrev);
1675   Record.clear();
1676 }
1677 
1678 void ModuleBitcodeWriter::writeDITemplateTypeParameter(
1679     const DITemplateTypeParameter *N, SmallVectorImpl<uint64_t> &Record,
1680     unsigned Abbrev) {
1681   Record.push_back(N->isDistinct());
1682   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1683   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1684 
1685   Stream.EmitRecord(bitc::METADATA_TEMPLATE_TYPE, Record, Abbrev);
1686   Record.clear();
1687 }
1688 
1689 void ModuleBitcodeWriter::writeDITemplateValueParameter(
1690     const DITemplateValueParameter *N, SmallVectorImpl<uint64_t> &Record,
1691     unsigned Abbrev) {
1692   Record.push_back(N->isDistinct());
1693   Record.push_back(N->getTag());
1694   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1695   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1696   Record.push_back(VE.getMetadataOrNullID(N->getValue()));
1697 
1698   Stream.EmitRecord(bitc::METADATA_TEMPLATE_VALUE, Record, Abbrev);
1699   Record.clear();
1700 }
1701 
1702 void ModuleBitcodeWriter::writeDIGlobalVariable(
1703     const DIGlobalVariable *N, SmallVectorImpl<uint64_t> &Record,
1704     unsigned Abbrev) {
1705   Record.push_back(N->isDistinct());
1706   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1707   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1708   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1709   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1710   Record.push_back(N->getLine());
1711   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1712   Record.push_back(N->isLocalToUnit());
1713   Record.push_back(N->isDefinition());
1714   Record.push_back(VE.getMetadataOrNullID(N->getRawExpr()));
1715   Record.push_back(VE.getMetadataOrNullID(N->getStaticDataMemberDeclaration()));
1716   Record.push_back(N->getAlignInBits());
1717 
1718   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR, Record, Abbrev);
1719   Record.clear();
1720 }
1721 
1722 void ModuleBitcodeWriter::writeDILocalVariable(
1723     const DILocalVariable *N, SmallVectorImpl<uint64_t> &Record,
1724     unsigned Abbrev) {
1725   // In order to support all possible bitcode formats in BitcodeReader we need
1726   // to distinguish the following cases:
1727   // 1) Record has no artificial tag (Record[1]),
1728   //   has no obsolete inlinedAt field (Record[9]).
1729   //   In this case Record size will be 8, HasAlignment flag is false.
1730   // 2) Record has artificial tag (Record[1]),
1731   //   has no obsolete inlignedAt field (Record[9]).
1732   //   In this case Record size will be 9, HasAlignment flag is false.
1733   // 3) Record has both artificial tag (Record[1]) and
1734   //   obsolete inlignedAt field (Record[9]).
1735   //   In this case Record size will be 10, HasAlignment flag is false.
1736   // 4) Record has neither artificial tag, nor inlignedAt field, but
1737   //   HasAlignment flag is true and Record[8] contains alignment value.
1738   const uint64_t HasAlignmentFlag = 1 << 1;
1739   Record.push_back((uint64_t)N->isDistinct() | HasAlignmentFlag);
1740   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1741   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1742   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1743   Record.push_back(N->getLine());
1744   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1745   Record.push_back(N->getArg());
1746   Record.push_back(N->getFlags());
1747   Record.push_back(N->getAlignInBits());
1748 
1749   Stream.EmitRecord(bitc::METADATA_LOCAL_VAR, Record, Abbrev);
1750   Record.clear();
1751 }
1752 
1753 void ModuleBitcodeWriter::writeDIExpression(const DIExpression *N,
1754                                             SmallVectorImpl<uint64_t> &Record,
1755                                             unsigned Abbrev) {
1756   Record.reserve(N->getElements().size() + 1);
1757 
1758   Record.push_back(N->isDistinct());
1759   Record.append(N->elements_begin(), N->elements_end());
1760 
1761   Stream.EmitRecord(bitc::METADATA_EXPRESSION, Record, Abbrev);
1762   Record.clear();
1763 }
1764 
1765 void ModuleBitcodeWriter::writeDIObjCProperty(const DIObjCProperty *N,
1766                                               SmallVectorImpl<uint64_t> &Record,
1767                                               unsigned Abbrev) {
1768   Record.push_back(N->isDistinct());
1769   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1770   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1771   Record.push_back(N->getLine());
1772   Record.push_back(VE.getMetadataOrNullID(N->getRawSetterName()));
1773   Record.push_back(VE.getMetadataOrNullID(N->getRawGetterName()));
1774   Record.push_back(N->getAttributes());
1775   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1776 
1777   Stream.EmitRecord(bitc::METADATA_OBJC_PROPERTY, Record, Abbrev);
1778   Record.clear();
1779 }
1780 
1781 void ModuleBitcodeWriter::writeDIImportedEntity(
1782     const DIImportedEntity *N, SmallVectorImpl<uint64_t> &Record,
1783     unsigned Abbrev) {
1784   Record.push_back(N->isDistinct());
1785   Record.push_back(N->getTag());
1786   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1787   Record.push_back(VE.getMetadataOrNullID(N->getEntity()));
1788   Record.push_back(N->getLine());
1789   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1790 
1791   Stream.EmitRecord(bitc::METADATA_IMPORTED_ENTITY, Record, Abbrev);
1792   Record.clear();
1793 }
1794 
1795 unsigned ModuleBitcodeWriter::createNamedMetadataAbbrev() {
1796   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1797   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
1798   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1799   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1800   return Stream.EmitAbbrev(Abbv);
1801 }
1802 
1803 void ModuleBitcodeWriter::writeNamedMetadata(
1804     SmallVectorImpl<uint64_t> &Record) {
1805   if (M.named_metadata_empty())
1806     return;
1807 
1808   unsigned Abbrev = createNamedMetadataAbbrev();
1809   for (const NamedMDNode &NMD : M.named_metadata()) {
1810     // Write name.
1811     StringRef Str = NMD.getName();
1812     Record.append(Str.bytes_begin(), Str.bytes_end());
1813     Stream.EmitRecord(bitc::METADATA_NAME, Record, Abbrev);
1814     Record.clear();
1815 
1816     // Write named metadata operands.
1817     for (const MDNode *N : NMD.operands())
1818       Record.push_back(VE.getMetadataID(N));
1819     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
1820     Record.clear();
1821   }
1822 }
1823 
1824 unsigned ModuleBitcodeWriter::createMetadataStringsAbbrev() {
1825   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
1826   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRINGS));
1827   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // # of strings
1828   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // offset to chars
1829   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
1830   return Stream.EmitAbbrev(Abbv);
1831 }
1832 
1833 /// Write out a record for MDString.
1834 ///
1835 /// All the metadata strings in a metadata block are emitted in a single
1836 /// record.  The sizes and strings themselves are shoved into a blob.
1837 void ModuleBitcodeWriter::writeMetadataStrings(
1838     ArrayRef<const Metadata *> Strings, SmallVectorImpl<uint64_t> &Record) {
1839   if (Strings.empty())
1840     return;
1841 
1842   // Start the record with the number of strings.
1843   Record.push_back(bitc::METADATA_STRINGS);
1844   Record.push_back(Strings.size());
1845 
1846   // Emit the sizes of the strings in the blob.
1847   SmallString<256> Blob;
1848   {
1849     BitstreamWriter W(Blob);
1850     for (const Metadata *MD : Strings)
1851       W.EmitVBR(cast<MDString>(MD)->getLength(), 6);
1852     W.FlushToWord();
1853   }
1854 
1855   // Add the offset to the strings to the record.
1856   Record.push_back(Blob.size());
1857 
1858   // Add the strings to the blob.
1859   for (const Metadata *MD : Strings)
1860     Blob.append(cast<MDString>(MD)->getString());
1861 
1862   // Emit the final record.
1863   Stream.EmitRecordWithBlob(createMetadataStringsAbbrev(), Record, Blob);
1864   Record.clear();
1865 }
1866 
1867 void ModuleBitcodeWriter::writeMetadataRecords(
1868     ArrayRef<const Metadata *> MDs, SmallVectorImpl<uint64_t> &Record) {
1869   if (MDs.empty())
1870     return;
1871 
1872   // Initialize MDNode abbreviations.
1873 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
1874 #include "llvm/IR/Metadata.def"
1875 
1876   for (const Metadata *MD : MDs) {
1877     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
1878       assert(N->isResolved() && "Expected forward references to be resolved");
1879 
1880       switch (N->getMetadataID()) {
1881       default:
1882         llvm_unreachable("Invalid MDNode subclass");
1883 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
1884   case Metadata::CLASS##Kind:                                                  \
1885     write##CLASS(cast<CLASS>(N), Record, CLASS##Abbrev);                       \
1886     continue;
1887 #include "llvm/IR/Metadata.def"
1888       }
1889     }
1890     writeValueAsMetadata(cast<ValueAsMetadata>(MD), Record);
1891   }
1892 }
1893 
1894 void ModuleBitcodeWriter::writeModuleMetadata() {
1895   if (!VE.hasMDs() && M.named_metadata_empty())
1896     return;
1897 
1898   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
1899   SmallVector<uint64_t, 64> Record;
1900   writeMetadataStrings(VE.getMDStrings(), Record);
1901   writeMetadataRecords(VE.getNonMDStrings(), Record);
1902   writeNamedMetadata(Record);
1903 
1904   auto AddDeclAttachedMetadata = [&](const GlobalObject &GO) {
1905     SmallVector<uint64_t, 4> Record;
1906     Record.push_back(VE.getValueID(&GO));
1907     pushGlobalMetadataAttachment(Record, GO);
1908     Stream.EmitRecord(bitc::METADATA_GLOBAL_DECL_ATTACHMENT, Record);
1909   };
1910   for (const Function &F : M)
1911     if (F.isDeclaration() && F.hasMetadata())
1912       AddDeclAttachedMetadata(F);
1913   // FIXME: Only store metadata for declarations here, and move data for global
1914   // variable definitions to a separate block (PR28134).
1915   for (const GlobalVariable &GV : M.globals())
1916     if (GV.hasMetadata())
1917       AddDeclAttachedMetadata(GV);
1918 
1919   Stream.ExitBlock();
1920 }
1921 
1922 void ModuleBitcodeWriter::writeFunctionMetadata(const Function &F) {
1923   if (!VE.hasMDs())
1924     return;
1925 
1926   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
1927   SmallVector<uint64_t, 64> Record;
1928   writeMetadataStrings(VE.getMDStrings(), Record);
1929   writeMetadataRecords(VE.getNonMDStrings(), Record);
1930   Stream.ExitBlock();
1931 }
1932 
1933 void ModuleBitcodeWriter::pushGlobalMetadataAttachment(
1934     SmallVectorImpl<uint64_t> &Record, const GlobalObject &GO) {
1935   // [n x [id, mdnode]]
1936   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
1937   GO.getAllMetadata(MDs);
1938   for (const auto &I : MDs) {
1939     Record.push_back(I.first);
1940     Record.push_back(VE.getMetadataID(I.second));
1941   }
1942 }
1943 
1944 void ModuleBitcodeWriter::writeFunctionMetadataAttachment(const Function &F) {
1945   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
1946 
1947   SmallVector<uint64_t, 64> Record;
1948 
1949   if (F.hasMetadata()) {
1950     pushGlobalMetadataAttachment(Record, F);
1951     Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
1952     Record.clear();
1953   }
1954 
1955   // Write metadata attachments
1956   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
1957   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
1958   for (const BasicBlock &BB : F)
1959     for (const Instruction &I : BB) {
1960       MDs.clear();
1961       I.getAllMetadataOtherThanDebugLoc(MDs);
1962 
1963       // If no metadata, ignore instruction.
1964       if (MDs.empty()) continue;
1965 
1966       Record.push_back(VE.getInstructionID(&I));
1967 
1968       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
1969         Record.push_back(MDs[i].first);
1970         Record.push_back(VE.getMetadataID(MDs[i].second));
1971       }
1972       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
1973       Record.clear();
1974     }
1975 
1976   Stream.ExitBlock();
1977 }
1978 
1979 void ModuleBitcodeWriter::writeModuleMetadataKinds() {
1980   SmallVector<uint64_t, 64> Record;
1981 
1982   // Write metadata kinds
1983   // METADATA_KIND - [n x [id, name]]
1984   SmallVector<StringRef, 8> Names;
1985   M.getMDKindNames(Names);
1986 
1987   if (Names.empty()) return;
1988 
1989   Stream.EnterSubblock(bitc::METADATA_KIND_BLOCK_ID, 3);
1990 
1991   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
1992     Record.push_back(MDKindID);
1993     StringRef KName = Names[MDKindID];
1994     Record.append(KName.begin(), KName.end());
1995 
1996     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
1997     Record.clear();
1998   }
1999 
2000   Stream.ExitBlock();
2001 }
2002 
2003 void ModuleBitcodeWriter::writeOperandBundleTags() {
2004   // Write metadata kinds
2005   //
2006   // OPERAND_BUNDLE_TAGS_BLOCK_ID : N x OPERAND_BUNDLE_TAG
2007   //
2008   // OPERAND_BUNDLE_TAG - [strchr x N]
2009 
2010   SmallVector<StringRef, 8> Tags;
2011   M.getOperandBundleTags(Tags);
2012 
2013   if (Tags.empty())
2014     return;
2015 
2016   Stream.EnterSubblock(bitc::OPERAND_BUNDLE_TAGS_BLOCK_ID, 3);
2017 
2018   SmallVector<uint64_t, 64> Record;
2019 
2020   for (auto Tag : Tags) {
2021     Record.append(Tag.begin(), Tag.end());
2022 
2023     Stream.EmitRecord(bitc::OPERAND_BUNDLE_TAG, Record, 0);
2024     Record.clear();
2025   }
2026 
2027   Stream.ExitBlock();
2028 }
2029 
2030 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
2031   if ((int64_t)V >= 0)
2032     Vals.push_back(V << 1);
2033   else
2034     Vals.push_back((-V << 1) | 1);
2035 }
2036 
2037 void ModuleBitcodeWriter::writeConstants(unsigned FirstVal, unsigned LastVal,
2038                                          bool isGlobal) {
2039   if (FirstVal == LastVal) return;
2040 
2041   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
2042 
2043   unsigned AggregateAbbrev = 0;
2044   unsigned String8Abbrev = 0;
2045   unsigned CString7Abbrev = 0;
2046   unsigned CString6Abbrev = 0;
2047   // If this is a constant pool for the module, emit module-specific abbrevs.
2048   if (isGlobal) {
2049     // Abbrev for CST_CODE_AGGREGATE.
2050     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2051     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
2052     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2053     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
2054     AggregateAbbrev = Stream.EmitAbbrev(Abbv);
2055 
2056     // Abbrev for CST_CODE_STRING.
2057     Abbv = new BitCodeAbbrev();
2058     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
2059     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2060     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2061     String8Abbrev = Stream.EmitAbbrev(Abbv);
2062     // Abbrev for CST_CODE_CSTRING.
2063     Abbv = new BitCodeAbbrev();
2064     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2065     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2066     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2067     CString7Abbrev = Stream.EmitAbbrev(Abbv);
2068     // Abbrev for CST_CODE_CSTRING.
2069     Abbv = new BitCodeAbbrev();
2070     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2071     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2072     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2073     CString6Abbrev = Stream.EmitAbbrev(Abbv);
2074   }
2075 
2076   SmallVector<uint64_t, 64> Record;
2077 
2078   const ValueEnumerator::ValueList &Vals = VE.getValues();
2079   Type *LastTy = nullptr;
2080   for (unsigned i = FirstVal; i != LastVal; ++i) {
2081     const Value *V = Vals[i].first;
2082     // If we need to switch types, do so now.
2083     if (V->getType() != LastTy) {
2084       LastTy = V->getType();
2085       Record.push_back(VE.getTypeID(LastTy));
2086       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
2087                         CONSTANTS_SETTYPE_ABBREV);
2088       Record.clear();
2089     }
2090 
2091     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
2092       Record.push_back(unsigned(IA->hasSideEffects()) |
2093                        unsigned(IA->isAlignStack()) << 1 |
2094                        unsigned(IA->getDialect()&1) << 2);
2095 
2096       // Add the asm string.
2097       const std::string &AsmStr = IA->getAsmString();
2098       Record.push_back(AsmStr.size());
2099       Record.append(AsmStr.begin(), AsmStr.end());
2100 
2101       // Add the constraint string.
2102       const std::string &ConstraintStr = IA->getConstraintString();
2103       Record.push_back(ConstraintStr.size());
2104       Record.append(ConstraintStr.begin(), ConstraintStr.end());
2105       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
2106       Record.clear();
2107       continue;
2108     }
2109     const Constant *C = cast<Constant>(V);
2110     unsigned Code = -1U;
2111     unsigned AbbrevToUse = 0;
2112     if (C->isNullValue()) {
2113       Code = bitc::CST_CODE_NULL;
2114     } else if (isa<UndefValue>(C)) {
2115       Code = bitc::CST_CODE_UNDEF;
2116     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
2117       if (IV->getBitWidth() <= 64) {
2118         uint64_t V = IV->getSExtValue();
2119         emitSignedInt64(Record, V);
2120         Code = bitc::CST_CODE_INTEGER;
2121         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
2122       } else {                             // Wide integers, > 64 bits in size.
2123         // We have an arbitrary precision integer value to write whose
2124         // bit width is > 64. However, in canonical unsigned integer
2125         // format it is likely that the high bits are going to be zero.
2126         // So, we only write the number of active words.
2127         unsigned NWords = IV->getValue().getActiveWords();
2128         const uint64_t *RawWords = IV->getValue().getRawData();
2129         for (unsigned i = 0; i != NWords; ++i) {
2130           emitSignedInt64(Record, RawWords[i]);
2131         }
2132         Code = bitc::CST_CODE_WIDE_INTEGER;
2133       }
2134     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
2135       Code = bitc::CST_CODE_FLOAT;
2136       Type *Ty = CFP->getType();
2137       if (Ty->isHalfTy() || Ty->isFloatTy() || Ty->isDoubleTy()) {
2138         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
2139       } else if (Ty->isX86_FP80Ty()) {
2140         // api needed to prevent premature destruction
2141         // bits are not in the same order as a normal i80 APInt, compensate.
2142         APInt api = CFP->getValueAPF().bitcastToAPInt();
2143         const uint64_t *p = api.getRawData();
2144         Record.push_back((p[1] << 48) | (p[0] >> 16));
2145         Record.push_back(p[0] & 0xffffLL);
2146       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
2147         APInt api = CFP->getValueAPF().bitcastToAPInt();
2148         const uint64_t *p = api.getRawData();
2149         Record.push_back(p[0]);
2150         Record.push_back(p[1]);
2151       } else {
2152         assert (0 && "Unknown FP type!");
2153       }
2154     } else if (isa<ConstantDataSequential>(C) &&
2155                cast<ConstantDataSequential>(C)->isString()) {
2156       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
2157       // Emit constant strings specially.
2158       unsigned NumElts = Str->getNumElements();
2159       // If this is a null-terminated string, use the denser CSTRING encoding.
2160       if (Str->isCString()) {
2161         Code = bitc::CST_CODE_CSTRING;
2162         --NumElts;  // Don't encode the null, which isn't allowed by char6.
2163       } else {
2164         Code = bitc::CST_CODE_STRING;
2165         AbbrevToUse = String8Abbrev;
2166       }
2167       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
2168       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
2169       for (unsigned i = 0; i != NumElts; ++i) {
2170         unsigned char V = Str->getElementAsInteger(i);
2171         Record.push_back(V);
2172         isCStr7 &= (V & 128) == 0;
2173         if (isCStrChar6)
2174           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
2175       }
2176 
2177       if (isCStrChar6)
2178         AbbrevToUse = CString6Abbrev;
2179       else if (isCStr7)
2180         AbbrevToUse = CString7Abbrev;
2181     } else if (const ConstantDataSequential *CDS =
2182                   dyn_cast<ConstantDataSequential>(C)) {
2183       Code = bitc::CST_CODE_DATA;
2184       Type *EltTy = CDS->getType()->getElementType();
2185       if (isa<IntegerType>(EltTy)) {
2186         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2187           Record.push_back(CDS->getElementAsInteger(i));
2188       } else {
2189         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2190           Record.push_back(
2191               CDS->getElementAsAPFloat(i).bitcastToAPInt().getLimitedValue());
2192       }
2193     } else if (isa<ConstantAggregate>(C)) {
2194       Code = bitc::CST_CODE_AGGREGATE;
2195       for (const Value *Op : C->operands())
2196         Record.push_back(VE.getValueID(Op));
2197       AbbrevToUse = AggregateAbbrev;
2198     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
2199       switch (CE->getOpcode()) {
2200       default:
2201         if (Instruction::isCast(CE->getOpcode())) {
2202           Code = bitc::CST_CODE_CE_CAST;
2203           Record.push_back(getEncodedCastOpcode(CE->getOpcode()));
2204           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2205           Record.push_back(VE.getValueID(C->getOperand(0)));
2206           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
2207         } else {
2208           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
2209           Code = bitc::CST_CODE_CE_BINOP;
2210           Record.push_back(getEncodedBinaryOpcode(CE->getOpcode()));
2211           Record.push_back(VE.getValueID(C->getOperand(0)));
2212           Record.push_back(VE.getValueID(C->getOperand(1)));
2213           uint64_t Flags = getOptimizationFlags(CE);
2214           if (Flags != 0)
2215             Record.push_back(Flags);
2216         }
2217         break;
2218       case Instruction::GetElementPtr: {
2219         Code = bitc::CST_CODE_CE_GEP;
2220         const auto *GO = cast<GEPOperator>(C);
2221         Record.push_back(VE.getTypeID(GO->getSourceElementType()));
2222         if (Optional<unsigned> Idx = GO->getInRangeIndex()) {
2223           Code = bitc::CST_CODE_CE_GEP_WITH_INRANGE_INDEX;
2224           Record.push_back((*Idx << 1) | GO->isInBounds());
2225         } else if (GO->isInBounds())
2226           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
2227         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
2228           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
2229           Record.push_back(VE.getValueID(C->getOperand(i)));
2230         }
2231         break;
2232       }
2233       case Instruction::Select:
2234         Code = bitc::CST_CODE_CE_SELECT;
2235         Record.push_back(VE.getValueID(C->getOperand(0)));
2236         Record.push_back(VE.getValueID(C->getOperand(1)));
2237         Record.push_back(VE.getValueID(C->getOperand(2)));
2238         break;
2239       case Instruction::ExtractElement:
2240         Code = bitc::CST_CODE_CE_EXTRACTELT;
2241         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2242         Record.push_back(VE.getValueID(C->getOperand(0)));
2243         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
2244         Record.push_back(VE.getValueID(C->getOperand(1)));
2245         break;
2246       case Instruction::InsertElement:
2247         Code = bitc::CST_CODE_CE_INSERTELT;
2248         Record.push_back(VE.getValueID(C->getOperand(0)));
2249         Record.push_back(VE.getValueID(C->getOperand(1)));
2250         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
2251         Record.push_back(VE.getValueID(C->getOperand(2)));
2252         break;
2253       case Instruction::ShuffleVector:
2254         // If the return type and argument types are the same, this is a
2255         // standard shufflevector instruction.  If the types are different,
2256         // then the shuffle is widening or truncating the input vectors, and
2257         // the argument type must also be encoded.
2258         if (C->getType() == C->getOperand(0)->getType()) {
2259           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
2260         } else {
2261           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
2262           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2263         }
2264         Record.push_back(VE.getValueID(C->getOperand(0)));
2265         Record.push_back(VE.getValueID(C->getOperand(1)));
2266         Record.push_back(VE.getValueID(C->getOperand(2)));
2267         break;
2268       case Instruction::ICmp:
2269       case Instruction::FCmp:
2270         Code = bitc::CST_CODE_CE_CMP;
2271         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2272         Record.push_back(VE.getValueID(C->getOperand(0)));
2273         Record.push_back(VE.getValueID(C->getOperand(1)));
2274         Record.push_back(CE->getPredicate());
2275         break;
2276       }
2277     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
2278       Code = bitc::CST_CODE_BLOCKADDRESS;
2279       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
2280       Record.push_back(VE.getValueID(BA->getFunction()));
2281       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
2282     } else {
2283 #ifndef NDEBUG
2284       C->dump();
2285 #endif
2286       llvm_unreachable("Unknown constant!");
2287     }
2288     Stream.EmitRecord(Code, Record, AbbrevToUse);
2289     Record.clear();
2290   }
2291 
2292   Stream.ExitBlock();
2293 }
2294 
2295 void ModuleBitcodeWriter::writeModuleConstants() {
2296   const ValueEnumerator::ValueList &Vals = VE.getValues();
2297 
2298   // Find the first constant to emit, which is the first non-globalvalue value.
2299   // We know globalvalues have been emitted by WriteModuleInfo.
2300   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
2301     if (!isa<GlobalValue>(Vals[i].first)) {
2302       writeConstants(i, Vals.size(), true);
2303       return;
2304     }
2305   }
2306 }
2307 
2308 /// pushValueAndType - The file has to encode both the value and type id for
2309 /// many values, because we need to know what type to create for forward
2310 /// references.  However, most operands are not forward references, so this type
2311 /// field is not needed.
2312 ///
2313 /// This function adds V's value ID to Vals.  If the value ID is higher than the
2314 /// instruction ID, then it is a forward reference, and it also includes the
2315 /// type ID.  The value ID that is written is encoded relative to the InstID.
2316 bool ModuleBitcodeWriter::pushValueAndType(const Value *V, unsigned InstID,
2317                                            SmallVectorImpl<unsigned> &Vals) {
2318   unsigned ValID = VE.getValueID(V);
2319   // Make encoding relative to the InstID.
2320   Vals.push_back(InstID - ValID);
2321   if (ValID >= InstID) {
2322     Vals.push_back(VE.getTypeID(V->getType()));
2323     return true;
2324   }
2325   return false;
2326 }
2327 
2328 void ModuleBitcodeWriter::writeOperandBundles(ImmutableCallSite CS,
2329                                               unsigned InstID) {
2330   SmallVector<unsigned, 64> Record;
2331   LLVMContext &C = CS.getInstruction()->getContext();
2332 
2333   for (unsigned i = 0, e = CS.getNumOperandBundles(); i != e; ++i) {
2334     const auto &Bundle = CS.getOperandBundleAt(i);
2335     Record.push_back(C.getOperandBundleTagID(Bundle.getTagName()));
2336 
2337     for (auto &Input : Bundle.Inputs)
2338       pushValueAndType(Input, InstID, Record);
2339 
2340     Stream.EmitRecord(bitc::FUNC_CODE_OPERAND_BUNDLE, Record);
2341     Record.clear();
2342   }
2343 }
2344 
2345 /// pushValue - Like pushValueAndType, but where the type of the value is
2346 /// omitted (perhaps it was already encoded in an earlier operand).
2347 void ModuleBitcodeWriter::pushValue(const Value *V, unsigned InstID,
2348                                     SmallVectorImpl<unsigned> &Vals) {
2349   unsigned ValID = VE.getValueID(V);
2350   Vals.push_back(InstID - ValID);
2351 }
2352 
2353 void ModuleBitcodeWriter::pushValueSigned(const Value *V, unsigned InstID,
2354                                           SmallVectorImpl<uint64_t> &Vals) {
2355   unsigned ValID = VE.getValueID(V);
2356   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
2357   emitSignedInt64(Vals, diff);
2358 }
2359 
2360 /// WriteInstruction - Emit an instruction to the specified stream.
2361 void ModuleBitcodeWriter::writeInstruction(const Instruction &I,
2362                                            unsigned InstID,
2363                                            SmallVectorImpl<unsigned> &Vals) {
2364   unsigned Code = 0;
2365   unsigned AbbrevToUse = 0;
2366   VE.setInstructionID(&I);
2367   switch (I.getOpcode()) {
2368   default:
2369     if (Instruction::isCast(I.getOpcode())) {
2370       Code = bitc::FUNC_CODE_INST_CAST;
2371       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2372         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
2373       Vals.push_back(VE.getTypeID(I.getType()));
2374       Vals.push_back(getEncodedCastOpcode(I.getOpcode()));
2375     } else {
2376       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
2377       Code = bitc::FUNC_CODE_INST_BINOP;
2378       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2379         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
2380       pushValue(I.getOperand(1), InstID, Vals);
2381       Vals.push_back(getEncodedBinaryOpcode(I.getOpcode()));
2382       uint64_t Flags = getOptimizationFlags(&I);
2383       if (Flags != 0) {
2384         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
2385           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
2386         Vals.push_back(Flags);
2387       }
2388     }
2389     break;
2390 
2391   case Instruction::GetElementPtr: {
2392     Code = bitc::FUNC_CODE_INST_GEP;
2393     AbbrevToUse = FUNCTION_INST_GEP_ABBREV;
2394     auto &GEPInst = cast<GetElementPtrInst>(I);
2395     Vals.push_back(GEPInst.isInBounds());
2396     Vals.push_back(VE.getTypeID(GEPInst.getSourceElementType()));
2397     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
2398       pushValueAndType(I.getOperand(i), InstID, Vals);
2399     break;
2400   }
2401   case Instruction::ExtractValue: {
2402     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
2403     pushValueAndType(I.getOperand(0), InstID, Vals);
2404     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
2405     Vals.append(EVI->idx_begin(), EVI->idx_end());
2406     break;
2407   }
2408   case Instruction::InsertValue: {
2409     Code = bitc::FUNC_CODE_INST_INSERTVAL;
2410     pushValueAndType(I.getOperand(0), InstID, Vals);
2411     pushValueAndType(I.getOperand(1), InstID, Vals);
2412     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
2413     Vals.append(IVI->idx_begin(), IVI->idx_end());
2414     break;
2415   }
2416   case Instruction::Select:
2417     Code = bitc::FUNC_CODE_INST_VSELECT;
2418     pushValueAndType(I.getOperand(1), InstID, Vals);
2419     pushValue(I.getOperand(2), InstID, Vals);
2420     pushValueAndType(I.getOperand(0), InstID, Vals);
2421     break;
2422   case Instruction::ExtractElement:
2423     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
2424     pushValueAndType(I.getOperand(0), InstID, Vals);
2425     pushValueAndType(I.getOperand(1), InstID, Vals);
2426     break;
2427   case Instruction::InsertElement:
2428     Code = bitc::FUNC_CODE_INST_INSERTELT;
2429     pushValueAndType(I.getOperand(0), InstID, Vals);
2430     pushValue(I.getOperand(1), InstID, Vals);
2431     pushValueAndType(I.getOperand(2), InstID, Vals);
2432     break;
2433   case Instruction::ShuffleVector:
2434     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
2435     pushValueAndType(I.getOperand(0), InstID, Vals);
2436     pushValue(I.getOperand(1), InstID, Vals);
2437     pushValue(I.getOperand(2), InstID, Vals);
2438     break;
2439   case Instruction::ICmp:
2440   case Instruction::FCmp: {
2441     // compare returning Int1Ty or vector of Int1Ty
2442     Code = bitc::FUNC_CODE_INST_CMP2;
2443     pushValueAndType(I.getOperand(0), InstID, Vals);
2444     pushValue(I.getOperand(1), InstID, Vals);
2445     Vals.push_back(cast<CmpInst>(I).getPredicate());
2446     uint64_t Flags = getOptimizationFlags(&I);
2447     if (Flags != 0)
2448       Vals.push_back(Flags);
2449     break;
2450   }
2451 
2452   case Instruction::Ret:
2453     {
2454       Code = bitc::FUNC_CODE_INST_RET;
2455       unsigned NumOperands = I.getNumOperands();
2456       if (NumOperands == 0)
2457         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
2458       else if (NumOperands == 1) {
2459         if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2460           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
2461       } else {
2462         for (unsigned i = 0, e = NumOperands; i != e; ++i)
2463           pushValueAndType(I.getOperand(i), InstID, Vals);
2464       }
2465     }
2466     break;
2467   case Instruction::Br:
2468     {
2469       Code = bitc::FUNC_CODE_INST_BR;
2470       const BranchInst &II = cast<BranchInst>(I);
2471       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
2472       if (II.isConditional()) {
2473         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
2474         pushValue(II.getCondition(), InstID, Vals);
2475       }
2476     }
2477     break;
2478   case Instruction::Switch:
2479     {
2480       Code = bitc::FUNC_CODE_INST_SWITCH;
2481       const SwitchInst &SI = cast<SwitchInst>(I);
2482       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
2483       pushValue(SI.getCondition(), InstID, Vals);
2484       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
2485       for (SwitchInst::ConstCaseIt Case : SI.cases()) {
2486         Vals.push_back(VE.getValueID(Case.getCaseValue()));
2487         Vals.push_back(VE.getValueID(Case.getCaseSuccessor()));
2488       }
2489     }
2490     break;
2491   case Instruction::IndirectBr:
2492     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
2493     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2494     // Encode the address operand as relative, but not the basic blocks.
2495     pushValue(I.getOperand(0), InstID, Vals);
2496     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
2497       Vals.push_back(VE.getValueID(I.getOperand(i)));
2498     break;
2499 
2500   case Instruction::Invoke: {
2501     const InvokeInst *II = cast<InvokeInst>(&I);
2502     const Value *Callee = II->getCalledValue();
2503     FunctionType *FTy = II->getFunctionType();
2504 
2505     if (II->hasOperandBundles())
2506       writeOperandBundles(II, InstID);
2507 
2508     Code = bitc::FUNC_CODE_INST_INVOKE;
2509 
2510     Vals.push_back(VE.getAttributeID(II->getAttributes()));
2511     Vals.push_back(II->getCallingConv() | 1 << 13);
2512     Vals.push_back(VE.getValueID(II->getNormalDest()));
2513     Vals.push_back(VE.getValueID(II->getUnwindDest()));
2514     Vals.push_back(VE.getTypeID(FTy));
2515     pushValueAndType(Callee, InstID, Vals);
2516 
2517     // Emit value #'s for the fixed parameters.
2518     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
2519       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
2520 
2521     // Emit type/value pairs for varargs params.
2522     if (FTy->isVarArg()) {
2523       for (unsigned i = FTy->getNumParams(), e = II->getNumArgOperands();
2524            i != e; ++i)
2525         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
2526     }
2527     break;
2528   }
2529   case Instruction::Resume:
2530     Code = bitc::FUNC_CODE_INST_RESUME;
2531     pushValueAndType(I.getOperand(0), InstID, Vals);
2532     break;
2533   case Instruction::CleanupRet: {
2534     Code = bitc::FUNC_CODE_INST_CLEANUPRET;
2535     const auto &CRI = cast<CleanupReturnInst>(I);
2536     pushValue(CRI.getCleanupPad(), InstID, Vals);
2537     if (CRI.hasUnwindDest())
2538       Vals.push_back(VE.getValueID(CRI.getUnwindDest()));
2539     break;
2540   }
2541   case Instruction::CatchRet: {
2542     Code = bitc::FUNC_CODE_INST_CATCHRET;
2543     const auto &CRI = cast<CatchReturnInst>(I);
2544     pushValue(CRI.getCatchPad(), InstID, Vals);
2545     Vals.push_back(VE.getValueID(CRI.getSuccessor()));
2546     break;
2547   }
2548   case Instruction::CleanupPad:
2549   case Instruction::CatchPad: {
2550     const auto &FuncletPad = cast<FuncletPadInst>(I);
2551     Code = isa<CatchPadInst>(FuncletPad) ? bitc::FUNC_CODE_INST_CATCHPAD
2552                                          : bitc::FUNC_CODE_INST_CLEANUPPAD;
2553     pushValue(FuncletPad.getParentPad(), InstID, Vals);
2554 
2555     unsigned NumArgOperands = FuncletPad.getNumArgOperands();
2556     Vals.push_back(NumArgOperands);
2557     for (unsigned Op = 0; Op != NumArgOperands; ++Op)
2558       pushValueAndType(FuncletPad.getArgOperand(Op), InstID, Vals);
2559     break;
2560   }
2561   case Instruction::CatchSwitch: {
2562     Code = bitc::FUNC_CODE_INST_CATCHSWITCH;
2563     const auto &CatchSwitch = cast<CatchSwitchInst>(I);
2564 
2565     pushValue(CatchSwitch.getParentPad(), InstID, Vals);
2566 
2567     unsigned NumHandlers = CatchSwitch.getNumHandlers();
2568     Vals.push_back(NumHandlers);
2569     for (const BasicBlock *CatchPadBB : CatchSwitch.handlers())
2570       Vals.push_back(VE.getValueID(CatchPadBB));
2571 
2572     if (CatchSwitch.hasUnwindDest())
2573       Vals.push_back(VE.getValueID(CatchSwitch.getUnwindDest()));
2574     break;
2575   }
2576   case Instruction::Unreachable:
2577     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
2578     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
2579     break;
2580 
2581   case Instruction::PHI: {
2582     const PHINode &PN = cast<PHINode>(I);
2583     Code = bitc::FUNC_CODE_INST_PHI;
2584     // With the newer instruction encoding, forward references could give
2585     // negative valued IDs.  This is most common for PHIs, so we use
2586     // signed VBRs.
2587     SmallVector<uint64_t, 128> Vals64;
2588     Vals64.push_back(VE.getTypeID(PN.getType()));
2589     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
2590       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64);
2591       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
2592     }
2593     // Emit a Vals64 vector and exit.
2594     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
2595     Vals64.clear();
2596     return;
2597   }
2598 
2599   case Instruction::LandingPad: {
2600     const LandingPadInst &LP = cast<LandingPadInst>(I);
2601     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
2602     Vals.push_back(VE.getTypeID(LP.getType()));
2603     Vals.push_back(LP.isCleanup());
2604     Vals.push_back(LP.getNumClauses());
2605     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
2606       if (LP.isCatch(I))
2607         Vals.push_back(LandingPadInst::Catch);
2608       else
2609         Vals.push_back(LandingPadInst::Filter);
2610       pushValueAndType(LP.getClause(I), InstID, Vals);
2611     }
2612     break;
2613   }
2614 
2615   case Instruction::Alloca: {
2616     Code = bitc::FUNC_CODE_INST_ALLOCA;
2617     const AllocaInst &AI = cast<AllocaInst>(I);
2618     Vals.push_back(VE.getTypeID(AI.getAllocatedType()));
2619     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2620     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
2621     unsigned AlignRecord = Log2_32(AI.getAlignment()) + 1;
2622     assert(Log2_32(Value::MaximumAlignment) + 1 < 1 << 5 &&
2623            "not enough bits for maximum alignment");
2624     assert(AlignRecord < 1 << 5 && "alignment greater than 1 << 64");
2625     AlignRecord |= AI.isUsedWithInAlloca() << 5;
2626     AlignRecord |= 1 << 6;
2627     AlignRecord |= AI.isSwiftError() << 7;
2628     Vals.push_back(AlignRecord);
2629     break;
2630   }
2631 
2632   case Instruction::Load:
2633     if (cast<LoadInst>(I).isAtomic()) {
2634       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
2635       pushValueAndType(I.getOperand(0), InstID, Vals);
2636     } else {
2637       Code = bitc::FUNC_CODE_INST_LOAD;
2638       if (!pushValueAndType(I.getOperand(0), InstID, Vals)) // ptr
2639         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
2640     }
2641     Vals.push_back(VE.getTypeID(I.getType()));
2642     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
2643     Vals.push_back(cast<LoadInst>(I).isVolatile());
2644     if (cast<LoadInst>(I).isAtomic()) {
2645       Vals.push_back(getEncodedOrdering(cast<LoadInst>(I).getOrdering()));
2646       Vals.push_back(getEncodedSynchScope(cast<LoadInst>(I).getSynchScope()));
2647     }
2648     break;
2649   case Instruction::Store:
2650     if (cast<StoreInst>(I).isAtomic())
2651       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
2652     else
2653       Code = bitc::FUNC_CODE_INST_STORE;
2654     pushValueAndType(I.getOperand(1), InstID, Vals); // ptrty + ptr
2655     pushValueAndType(I.getOperand(0), InstID, Vals); // valty + val
2656     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
2657     Vals.push_back(cast<StoreInst>(I).isVolatile());
2658     if (cast<StoreInst>(I).isAtomic()) {
2659       Vals.push_back(getEncodedOrdering(cast<StoreInst>(I).getOrdering()));
2660       Vals.push_back(getEncodedSynchScope(cast<StoreInst>(I).getSynchScope()));
2661     }
2662     break;
2663   case Instruction::AtomicCmpXchg:
2664     Code = bitc::FUNC_CODE_INST_CMPXCHG;
2665     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
2666     pushValueAndType(I.getOperand(1), InstID, Vals); // cmp.
2667     pushValue(I.getOperand(2), InstID, Vals);        // newval.
2668     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
2669     Vals.push_back(
2670         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
2671     Vals.push_back(
2672         getEncodedSynchScope(cast<AtomicCmpXchgInst>(I).getSynchScope()));
2673     Vals.push_back(
2674         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
2675     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
2676     break;
2677   case Instruction::AtomicRMW:
2678     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
2679     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
2680     pushValue(I.getOperand(1), InstID, Vals);        // val.
2681     Vals.push_back(
2682         getEncodedRMWOperation(cast<AtomicRMWInst>(I).getOperation()));
2683     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
2684     Vals.push_back(getEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
2685     Vals.push_back(
2686         getEncodedSynchScope(cast<AtomicRMWInst>(I).getSynchScope()));
2687     break;
2688   case Instruction::Fence:
2689     Code = bitc::FUNC_CODE_INST_FENCE;
2690     Vals.push_back(getEncodedOrdering(cast<FenceInst>(I).getOrdering()));
2691     Vals.push_back(getEncodedSynchScope(cast<FenceInst>(I).getSynchScope()));
2692     break;
2693   case Instruction::Call: {
2694     const CallInst &CI = cast<CallInst>(I);
2695     FunctionType *FTy = CI.getFunctionType();
2696 
2697     if (CI.hasOperandBundles())
2698       writeOperandBundles(&CI, InstID);
2699 
2700     Code = bitc::FUNC_CODE_INST_CALL;
2701 
2702     Vals.push_back(VE.getAttributeID(CI.getAttributes()));
2703 
2704     unsigned Flags = getOptimizationFlags(&I);
2705     Vals.push_back(CI.getCallingConv() << bitc::CALL_CCONV |
2706                    unsigned(CI.isTailCall()) << bitc::CALL_TAIL |
2707                    unsigned(CI.isMustTailCall()) << bitc::CALL_MUSTTAIL |
2708                    1 << bitc::CALL_EXPLICIT_TYPE |
2709                    unsigned(CI.isNoTailCall()) << bitc::CALL_NOTAIL |
2710                    unsigned(Flags != 0) << bitc::CALL_FMF);
2711     if (Flags != 0)
2712       Vals.push_back(Flags);
2713 
2714     Vals.push_back(VE.getTypeID(FTy));
2715     pushValueAndType(CI.getCalledValue(), InstID, Vals); // Callee
2716 
2717     // Emit value #'s for the fixed parameters.
2718     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
2719       // Check for labels (can happen with asm labels).
2720       if (FTy->getParamType(i)->isLabelTy())
2721         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
2722       else
2723         pushValue(CI.getArgOperand(i), InstID, Vals); // fixed param.
2724     }
2725 
2726     // Emit type/value pairs for varargs params.
2727     if (FTy->isVarArg()) {
2728       for (unsigned i = FTy->getNumParams(), e = CI.getNumArgOperands();
2729            i != e; ++i)
2730         pushValueAndType(CI.getArgOperand(i), InstID, Vals); // varargs
2731     }
2732     break;
2733   }
2734   case Instruction::VAArg:
2735     Code = bitc::FUNC_CODE_INST_VAARG;
2736     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
2737     pushValue(I.getOperand(0), InstID, Vals);                   // valist.
2738     Vals.push_back(VE.getTypeID(I.getType())); // restype.
2739     break;
2740   }
2741 
2742   Stream.EmitRecord(Code, Vals, AbbrevToUse);
2743   Vals.clear();
2744 }
2745 
2746 /// Emit names for globals/functions etc. \p IsModuleLevel is true when
2747 /// we are writing the module-level VST, where we are including a function
2748 /// bitcode index and need to backpatch the VST forward declaration record.
2749 void ModuleBitcodeWriter::writeValueSymbolTable(
2750     const ValueSymbolTable &VST, bool IsModuleLevel,
2751     DenseMap<const Function *, uint64_t> *FunctionToBitcodeIndex) {
2752   if (VST.empty()) {
2753     // writeValueSymbolTableForwardDecl should have returned early as
2754     // well. Ensure this handling remains in sync by asserting that
2755     // the placeholder offset is not set.
2756     assert(!IsModuleLevel || !hasVSTOffsetPlaceholder());
2757     return;
2758   }
2759 
2760   if (IsModuleLevel && hasVSTOffsetPlaceholder()) {
2761     // Get the offset of the VST we are writing, and backpatch it into
2762     // the VST forward declaration record.
2763     uint64_t VSTOffset = Stream.GetCurrentBitNo();
2764     // The BitcodeStartBit was the stream offset of the actual bitcode
2765     // (e.g. excluding any initial darwin header).
2766     VSTOffset -= bitcodeStartBit();
2767     assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
2768     Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32);
2769   }
2770 
2771   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
2772 
2773   // For the module-level VST, add abbrev Ids for the VST_CODE_FNENTRY
2774   // records, which are not used in the per-function VSTs.
2775   unsigned FnEntry8BitAbbrev;
2776   unsigned FnEntry7BitAbbrev;
2777   unsigned FnEntry6BitAbbrev;
2778   unsigned GUIDEntryAbbrev;
2779   if (IsModuleLevel && hasVSTOffsetPlaceholder()) {
2780     // 8-bit fixed-width VST_CODE_FNENTRY function strings.
2781     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2782     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
2783     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
2784     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
2785     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2786     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2787     FnEntry8BitAbbrev = Stream.EmitAbbrev(Abbv);
2788 
2789     // 7-bit fixed width VST_CODE_FNENTRY function strings.
2790     Abbv = new BitCodeAbbrev();
2791     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
2792     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
2793     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
2794     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2795     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2796     FnEntry7BitAbbrev = Stream.EmitAbbrev(Abbv);
2797 
2798     // 6-bit char6 VST_CODE_FNENTRY function strings.
2799     Abbv = new BitCodeAbbrev();
2800     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
2801     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
2802     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
2803     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2804     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2805     FnEntry6BitAbbrev = Stream.EmitAbbrev(Abbv);
2806 
2807     // FIXME: Change the name of this record as it is now used by
2808     // the per-module index as well.
2809     Abbv = new BitCodeAbbrev();
2810     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_COMBINED_ENTRY));
2811     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
2812     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // refguid
2813     GUIDEntryAbbrev = Stream.EmitAbbrev(Abbv);
2814   }
2815 
2816   // FIXME: Set up the abbrev, we know how many values there are!
2817   // FIXME: We know if the type names can use 7-bit ascii.
2818   SmallVector<uint64_t, 64> NameVals;
2819 
2820   for (const ValueName &Name : VST) {
2821     // Figure out the encoding to use for the name.
2822     StringEncoding Bits =
2823         getStringEncoding(Name.getKeyData(), Name.getKeyLength());
2824 
2825     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
2826     NameVals.push_back(VE.getValueID(Name.getValue()));
2827 
2828     Function *F = dyn_cast<Function>(Name.getValue());
2829     if (!F) {
2830       // If value is an alias, need to get the aliased base object to
2831       // see if it is a function.
2832       auto *GA = dyn_cast<GlobalAlias>(Name.getValue());
2833       if (GA && GA->getBaseObject())
2834         F = dyn_cast<Function>(GA->getBaseObject());
2835     }
2836 
2837     // VST_CODE_ENTRY:   [valueid, namechar x N]
2838     // VST_CODE_FNENTRY: [valueid, funcoffset, namechar x N]
2839     // VST_CODE_BBENTRY: [bbid, namechar x N]
2840     unsigned Code;
2841     if (isa<BasicBlock>(Name.getValue())) {
2842       Code = bitc::VST_CODE_BBENTRY;
2843       if (Bits == SE_Char6)
2844         AbbrevToUse = VST_BBENTRY_6_ABBREV;
2845     } else if (F && !F->isDeclaration()) {
2846       // Must be the module-level VST, where we pass in the Index and
2847       // have a VSTOffsetPlaceholder. The function-level VST should not
2848       // contain any Function symbols.
2849       assert(FunctionToBitcodeIndex);
2850       assert(hasVSTOffsetPlaceholder());
2851 
2852       // Save the word offset of the function (from the start of the
2853       // actual bitcode written to the stream).
2854       uint64_t BitcodeIndex = (*FunctionToBitcodeIndex)[F] - bitcodeStartBit();
2855       assert((BitcodeIndex & 31) == 0 && "function block not 32-bit aligned");
2856       NameVals.push_back(BitcodeIndex / 32);
2857 
2858       Code = bitc::VST_CODE_FNENTRY;
2859       AbbrevToUse = FnEntry8BitAbbrev;
2860       if (Bits == SE_Char6)
2861         AbbrevToUse = FnEntry6BitAbbrev;
2862       else if (Bits == SE_Fixed7)
2863         AbbrevToUse = FnEntry7BitAbbrev;
2864     } else {
2865       Code = bitc::VST_CODE_ENTRY;
2866       if (Bits == SE_Char6)
2867         AbbrevToUse = VST_ENTRY_6_ABBREV;
2868       else if (Bits == SE_Fixed7)
2869         AbbrevToUse = VST_ENTRY_7_ABBREV;
2870     }
2871 
2872     for (const auto P : Name.getKey())
2873       NameVals.push_back((unsigned char)P);
2874 
2875     // Emit the finished record.
2876     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
2877     NameVals.clear();
2878   }
2879   // Emit any GUID valueIDs created for indirect call edges into the
2880   // module-level VST.
2881   if (IsModuleLevel && hasVSTOffsetPlaceholder())
2882     for (const auto &GI : valueIds()) {
2883       NameVals.push_back(GI.second);
2884       NameVals.push_back(GI.first);
2885       Stream.EmitRecord(bitc::VST_CODE_COMBINED_ENTRY, NameVals,
2886                         GUIDEntryAbbrev);
2887       NameVals.clear();
2888     }
2889   Stream.ExitBlock();
2890 }
2891 
2892 /// Emit function names and summary offsets for the combined index
2893 /// used by ThinLTO.
2894 void IndexBitcodeWriter::writeCombinedValueSymbolTable() {
2895   assert(hasVSTOffsetPlaceholder() && "Expected non-zero VSTOffsetPlaceholder");
2896   // Get the offset of the VST we are writing, and backpatch it into
2897   // the VST forward declaration record.
2898   uint64_t VSTOffset = Stream.GetCurrentBitNo();
2899   assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
2900   Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32);
2901 
2902   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
2903 
2904   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
2905   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_COMBINED_ENTRY));
2906   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
2907   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // refguid
2908   unsigned EntryAbbrev = Stream.EmitAbbrev(Abbv);
2909 
2910   SmallVector<uint64_t, 64> NameVals;
2911   for (const auto &GVI : valueIds()) {
2912     // VST_CODE_COMBINED_ENTRY: [valueid, refguid]
2913     NameVals.push_back(GVI.second);
2914     NameVals.push_back(GVI.first);
2915 
2916     // Emit the finished record.
2917     Stream.EmitRecord(bitc::VST_CODE_COMBINED_ENTRY, NameVals, EntryAbbrev);
2918     NameVals.clear();
2919   }
2920   Stream.ExitBlock();
2921 }
2922 
2923 void ModuleBitcodeWriter::writeUseList(UseListOrder &&Order) {
2924   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
2925   unsigned Code;
2926   if (isa<BasicBlock>(Order.V))
2927     Code = bitc::USELIST_CODE_BB;
2928   else
2929     Code = bitc::USELIST_CODE_DEFAULT;
2930 
2931   SmallVector<uint64_t, 64> Record(Order.Shuffle.begin(), Order.Shuffle.end());
2932   Record.push_back(VE.getValueID(Order.V));
2933   Stream.EmitRecord(Code, Record);
2934 }
2935 
2936 void ModuleBitcodeWriter::writeUseListBlock(const Function *F) {
2937   assert(VE.shouldPreserveUseListOrder() &&
2938          "Expected to be preserving use-list order");
2939 
2940   auto hasMore = [&]() {
2941     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
2942   };
2943   if (!hasMore())
2944     // Nothing to do.
2945     return;
2946 
2947   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
2948   while (hasMore()) {
2949     writeUseList(std::move(VE.UseListOrders.back()));
2950     VE.UseListOrders.pop_back();
2951   }
2952   Stream.ExitBlock();
2953 }
2954 
2955 /// Emit a function body to the module stream.
2956 void ModuleBitcodeWriter::writeFunction(
2957     const Function &F,
2958     DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
2959   // Save the bitcode index of the start of this function block for recording
2960   // in the VST.
2961   FunctionToBitcodeIndex[&F] = Stream.GetCurrentBitNo();
2962 
2963   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
2964   VE.incorporateFunction(F);
2965 
2966   SmallVector<unsigned, 64> Vals;
2967 
2968   // Emit the number of basic blocks, so the reader can create them ahead of
2969   // time.
2970   Vals.push_back(VE.getBasicBlocks().size());
2971   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
2972   Vals.clear();
2973 
2974   // If there are function-local constants, emit them now.
2975   unsigned CstStart, CstEnd;
2976   VE.getFunctionConstantRange(CstStart, CstEnd);
2977   writeConstants(CstStart, CstEnd, false);
2978 
2979   // If there is function-local metadata, emit it now.
2980   writeFunctionMetadata(F);
2981 
2982   // Keep a running idea of what the instruction ID is.
2983   unsigned InstID = CstEnd;
2984 
2985   bool NeedsMetadataAttachment = F.hasMetadata();
2986 
2987   DILocation *LastDL = nullptr;
2988   // Finally, emit all the instructions, in order.
2989   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
2990     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
2991          I != E; ++I) {
2992       writeInstruction(*I, InstID, Vals);
2993 
2994       if (!I->getType()->isVoidTy())
2995         ++InstID;
2996 
2997       // If the instruction has metadata, write a metadata attachment later.
2998       NeedsMetadataAttachment |= I->hasMetadataOtherThanDebugLoc();
2999 
3000       // If the instruction has a debug location, emit it.
3001       DILocation *DL = I->getDebugLoc();
3002       if (!DL)
3003         continue;
3004 
3005       if (DL == LastDL) {
3006         // Just repeat the same debug loc as last time.
3007         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
3008         continue;
3009       }
3010 
3011       Vals.push_back(DL->getLine());
3012       Vals.push_back(DL->getColumn());
3013       Vals.push_back(VE.getMetadataOrNullID(DL->getScope()));
3014       Vals.push_back(VE.getMetadataOrNullID(DL->getInlinedAt()));
3015       Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
3016       Vals.clear();
3017 
3018       LastDL = DL;
3019     }
3020 
3021   // Emit names for all the instructions etc.
3022   if (auto *Symtab = F.getValueSymbolTable())
3023     writeValueSymbolTable(*Symtab);
3024 
3025   if (NeedsMetadataAttachment)
3026     writeFunctionMetadataAttachment(F);
3027   if (VE.shouldPreserveUseListOrder())
3028     writeUseListBlock(&F);
3029   VE.purgeFunction();
3030   Stream.ExitBlock();
3031 }
3032 
3033 // Emit blockinfo, which defines the standard abbreviations etc.
3034 void ModuleBitcodeWriter::writeBlockInfo() {
3035   // We only want to emit block info records for blocks that have multiple
3036   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
3037   // Other blocks can define their abbrevs inline.
3038   Stream.EnterBlockInfoBlock();
3039 
3040   { // 8-bit fixed-width VST_CODE_ENTRY/VST_CODE_BBENTRY strings.
3041     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
3042     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
3043     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3044     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3045     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3046     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3047         VST_ENTRY_8_ABBREV)
3048       llvm_unreachable("Unexpected abbrev ordering!");
3049   }
3050 
3051   { // 7-bit fixed width VST_CODE_ENTRY strings.
3052     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
3053     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3054     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3055     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3056     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3057     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3058         VST_ENTRY_7_ABBREV)
3059       llvm_unreachable("Unexpected abbrev ordering!");
3060   }
3061   { // 6-bit char6 VST_CODE_ENTRY strings.
3062     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
3063     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3064     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3065     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3066     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3067     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3068         VST_ENTRY_6_ABBREV)
3069       llvm_unreachable("Unexpected abbrev ordering!");
3070   }
3071   { // 6-bit char6 VST_CODE_BBENTRY strings.
3072     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
3073     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
3074     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3075     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3076     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3077     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3078         VST_BBENTRY_6_ABBREV)
3079       llvm_unreachable("Unexpected abbrev ordering!");
3080   }
3081 
3082 
3083 
3084   { // SETTYPE abbrev for CONSTANTS_BLOCK.
3085     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
3086     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
3087     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
3088                               VE.computeBitsRequiredForTypeIndicies()));
3089     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3090         CONSTANTS_SETTYPE_ABBREV)
3091       llvm_unreachable("Unexpected abbrev ordering!");
3092   }
3093 
3094   { // INTEGER abbrev for CONSTANTS_BLOCK.
3095     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
3096     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
3097     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3098     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3099         CONSTANTS_INTEGER_ABBREV)
3100       llvm_unreachable("Unexpected abbrev ordering!");
3101   }
3102 
3103   { // CE_CAST abbrev for CONSTANTS_BLOCK.
3104     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
3105     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
3106     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
3107     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
3108                               VE.computeBitsRequiredForTypeIndicies()));
3109     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
3110 
3111     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3112         CONSTANTS_CE_CAST_Abbrev)
3113       llvm_unreachable("Unexpected abbrev ordering!");
3114   }
3115   { // NULL abbrev for CONSTANTS_BLOCK.
3116     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
3117     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
3118     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3119         CONSTANTS_NULL_Abbrev)
3120       llvm_unreachable("Unexpected abbrev ordering!");
3121   }
3122 
3123   // FIXME: This should only use space for first class types!
3124 
3125   { // INST_LOAD abbrev for FUNCTION_BLOCK.
3126     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
3127     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
3128     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
3129     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
3130                               VE.computeBitsRequiredForTypeIndicies()));
3131     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
3132     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
3133     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3134         FUNCTION_INST_LOAD_ABBREV)
3135       llvm_unreachable("Unexpected abbrev ordering!");
3136   }
3137   { // INST_BINOP abbrev for FUNCTION_BLOCK.
3138     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
3139     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3140     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3141     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3142     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3143     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3144         FUNCTION_INST_BINOP_ABBREV)
3145       llvm_unreachable("Unexpected abbrev ordering!");
3146   }
3147   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
3148     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
3149     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3150     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3151     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3152     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3153     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7)); // flags
3154     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3155         FUNCTION_INST_BINOP_FLAGS_ABBREV)
3156       llvm_unreachable("Unexpected abbrev ordering!");
3157   }
3158   { // INST_CAST abbrev for FUNCTION_BLOCK.
3159     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
3160     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
3161     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
3162     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
3163                               VE.computeBitsRequiredForTypeIndicies()));
3164     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
3165     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3166         FUNCTION_INST_CAST_ABBREV)
3167       llvm_unreachable("Unexpected abbrev ordering!");
3168   }
3169 
3170   { // INST_RET abbrev for FUNCTION_BLOCK.
3171     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
3172     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3173     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3174         FUNCTION_INST_RET_VOID_ABBREV)
3175       llvm_unreachable("Unexpected abbrev ordering!");
3176   }
3177   { // INST_RET abbrev for FUNCTION_BLOCK.
3178     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
3179     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3180     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
3181     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3182         FUNCTION_INST_RET_VAL_ABBREV)
3183       llvm_unreachable("Unexpected abbrev ordering!");
3184   }
3185   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
3186     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
3187     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
3188     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3189         FUNCTION_INST_UNREACHABLE_ABBREV)
3190       llvm_unreachable("Unexpected abbrev ordering!");
3191   }
3192   {
3193     BitCodeAbbrev *Abbv = new BitCodeAbbrev();
3194     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_GEP));
3195     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
3196     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, // dest ty
3197                               Log2_32_Ceil(VE.getTypes().size() + 1)));
3198     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3199     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
3200     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3201         FUNCTION_INST_GEP_ABBREV)
3202       llvm_unreachable("Unexpected abbrev ordering!");
3203   }
3204 
3205   Stream.ExitBlock();
3206 }
3207 
3208 /// Write the module path strings, currently only used when generating
3209 /// a combined index file.
3210 void IndexBitcodeWriter::writeModStrings() {
3211   Stream.EnterSubblock(bitc::MODULE_STRTAB_BLOCK_ID, 3);
3212 
3213   // TODO: See which abbrev sizes we actually need to emit
3214 
3215   // 8-bit fixed-width MST_ENTRY strings.
3216   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
3217   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3218   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3219   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3220   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3221   unsigned Abbrev8Bit = Stream.EmitAbbrev(Abbv);
3222 
3223   // 7-bit fixed width MST_ENTRY strings.
3224   Abbv = new BitCodeAbbrev();
3225   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3226   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3227   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3228   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3229   unsigned Abbrev7Bit = Stream.EmitAbbrev(Abbv);
3230 
3231   // 6-bit char6 MST_ENTRY strings.
3232   Abbv = new BitCodeAbbrev();
3233   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3234   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3235   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3236   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3237   unsigned Abbrev6Bit = Stream.EmitAbbrev(Abbv);
3238 
3239   // Module Hash, 160 bits SHA1. Optionally, emitted after each MST_CODE_ENTRY.
3240   Abbv = new BitCodeAbbrev();
3241   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_HASH));
3242   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3243   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3244   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3245   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3246   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3247   unsigned AbbrevHash = Stream.EmitAbbrev(Abbv);
3248 
3249   SmallVector<unsigned, 64> Vals;
3250   for (const auto &MPSE : Index.modulePaths()) {
3251     if (!doIncludeModule(MPSE.getKey()))
3252       continue;
3253     StringEncoding Bits =
3254         getStringEncoding(MPSE.getKey().data(), MPSE.getKey().size());
3255     unsigned AbbrevToUse = Abbrev8Bit;
3256     if (Bits == SE_Char6)
3257       AbbrevToUse = Abbrev6Bit;
3258     else if (Bits == SE_Fixed7)
3259       AbbrevToUse = Abbrev7Bit;
3260 
3261     Vals.push_back(MPSE.getValue().first);
3262 
3263     for (const auto P : MPSE.getKey())
3264       Vals.push_back((unsigned char)P);
3265 
3266     // Emit the finished record.
3267     Stream.EmitRecord(bitc::MST_CODE_ENTRY, Vals, AbbrevToUse);
3268 
3269     Vals.clear();
3270     // Emit an optional hash for the module now
3271     auto &Hash = MPSE.getValue().second;
3272     bool AllZero = true; // Detect if the hash is empty, and do not generate it
3273     for (auto Val : Hash) {
3274       if (Val)
3275         AllZero = false;
3276       Vals.push_back(Val);
3277     }
3278     if (!AllZero) {
3279       // Emit the hash record.
3280       Stream.EmitRecord(bitc::MST_CODE_HASH, Vals, AbbrevHash);
3281     }
3282 
3283     Vals.clear();
3284   }
3285   Stream.ExitBlock();
3286 }
3287 
3288 // Helper to emit a single function summary record.
3289 void ModuleBitcodeWriter::writePerModuleFunctionSummaryRecord(
3290     SmallVector<uint64_t, 64> &NameVals, GlobalValueSummary *Summary,
3291     unsigned ValueID, unsigned FSCallsAbbrev, unsigned FSCallsProfileAbbrev,
3292     const Function &F) {
3293   NameVals.push_back(ValueID);
3294 
3295   FunctionSummary *FS = cast<FunctionSummary>(Summary);
3296   NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
3297   NameVals.push_back(FS->instCount());
3298   NameVals.push_back(FS->refs().size());
3299 
3300   unsigned SizeBeforeRefs = NameVals.size();
3301   for (auto &RI : FS->refs())
3302     NameVals.push_back(VE.getValueID(RI.getValue()));
3303   // Sort the refs for determinism output, the vector returned by FS->refs() has
3304   // been initialized from a DenseSet.
3305   std::sort(NameVals.begin() + SizeBeforeRefs, NameVals.end());
3306 
3307   std::vector<FunctionSummary::EdgeTy> Calls = FS->calls();
3308   std::sort(Calls.begin(), Calls.end(),
3309             [this](const FunctionSummary::EdgeTy &L,
3310                    const FunctionSummary::EdgeTy &R) {
3311               return getValueId(L.first) < getValueId(R.first);
3312             });
3313   bool HasProfileData = F.getEntryCount().hasValue();
3314   for (auto &ECI : Calls) {
3315     NameVals.push_back(getValueId(ECI.first));
3316     if (HasProfileData)
3317       NameVals.push_back(static_cast<uint8_t>(ECI.second.Hotness));
3318   }
3319 
3320   unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
3321   unsigned Code =
3322       (HasProfileData ? bitc::FS_PERMODULE_PROFILE : bitc::FS_PERMODULE);
3323 
3324   // Emit the finished record.
3325   Stream.EmitRecord(Code, NameVals, FSAbbrev);
3326   NameVals.clear();
3327 }
3328 
3329 // Collect the global value references in the given variable's initializer,
3330 // and emit them in a summary record.
3331 void ModuleBitcodeWriter::writeModuleLevelReferences(
3332     const GlobalVariable &V, SmallVector<uint64_t, 64> &NameVals,
3333     unsigned FSModRefsAbbrev) {
3334   auto Summaries =
3335       Index->findGlobalValueSummaryList(GlobalValue::getGUID(V.getName()));
3336   if (Summaries == Index->end()) {
3337     // Only declarations should not have a summary (a declaration might however
3338     // have a summary if the def was in module level asm).
3339     assert(V.isDeclaration());
3340     return;
3341   }
3342   auto *Summary = Summaries->second.front().get();
3343   NameVals.push_back(VE.getValueID(&V));
3344   GlobalVarSummary *VS = cast<GlobalVarSummary>(Summary);
3345   NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
3346 
3347   unsigned SizeBeforeRefs = NameVals.size();
3348   for (auto &RI : VS->refs())
3349     NameVals.push_back(VE.getValueID(RI.getValue()));
3350   // Sort the refs for determinism output, the vector returned by FS->refs() has
3351   // been initialized from a DenseSet.
3352   std::sort(NameVals.begin() + SizeBeforeRefs, NameVals.end());
3353 
3354   Stream.EmitRecord(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS, NameVals,
3355                     FSModRefsAbbrev);
3356   NameVals.clear();
3357 }
3358 
3359 // Current version for the summary.
3360 // This is bumped whenever we introduce changes in the way some record are
3361 // interpreted, like flags for instance.
3362 static const uint64_t INDEX_VERSION = 2;
3363 
3364 /// Emit the per-module summary section alongside the rest of
3365 /// the module's bitcode.
3366 void ModuleBitcodeWriter::writePerModuleGlobalValueSummary() {
3367   Stream.EnterSubblock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID, 4);
3368 
3369   Stream.EmitRecord(bitc::FS_VERSION, ArrayRef<uint64_t>{INDEX_VERSION});
3370 
3371   if (Index->begin() == Index->end()) {
3372     Stream.ExitBlock();
3373     return;
3374   }
3375 
3376   // Abbrev for FS_PERMODULE.
3377   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
3378   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE));
3379   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3380   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3381   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3382   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3383   // numrefs x valueid, n x (valueid)
3384   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3385   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3386   unsigned FSCallsAbbrev = Stream.EmitAbbrev(Abbv);
3387 
3388   // Abbrev for FS_PERMODULE_PROFILE.
3389   Abbv = new BitCodeAbbrev();
3390   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_PROFILE));
3391   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3392   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3393   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3394   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3395   // numrefs x valueid, n x (valueid, hotness)
3396   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3397   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3398   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(Abbv);
3399 
3400   // Abbrev for FS_PERMODULE_GLOBALVAR_INIT_REFS.
3401   Abbv = new BitCodeAbbrev();
3402   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS));
3403   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
3404   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
3405   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));  // valueids
3406   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3407   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(Abbv);
3408 
3409   // Abbrev for FS_ALIAS.
3410   Abbv = new BitCodeAbbrev();
3411   Abbv->Add(BitCodeAbbrevOp(bitc::FS_ALIAS));
3412   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3413   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3414   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3415   unsigned FSAliasAbbrev = Stream.EmitAbbrev(Abbv);
3416 
3417   SmallVector<uint64_t, 64> NameVals;
3418   // Iterate over the list of functions instead of the Index to
3419   // ensure the ordering is stable.
3420   for (const Function &F : M) {
3421     // Summary emission does not support anonymous functions, they have to
3422     // renamed using the anonymous function renaming pass.
3423     if (!F.hasName())
3424       report_fatal_error("Unexpected anonymous function when writing summary");
3425 
3426     auto Summaries =
3427         Index->findGlobalValueSummaryList(GlobalValue::getGUID(F.getName()));
3428     if (Summaries == Index->end()) {
3429       // Only declarations should not have a summary (a declaration might
3430       // however have a summary if the def was in module level asm).
3431       assert(F.isDeclaration());
3432       continue;
3433     }
3434     auto *Summary = Summaries->second.front().get();
3435     writePerModuleFunctionSummaryRecord(NameVals, Summary, VE.getValueID(&F),
3436                                         FSCallsAbbrev, FSCallsProfileAbbrev, F);
3437   }
3438 
3439   // Capture references from GlobalVariable initializers, which are outside
3440   // of a function scope.
3441   for (const GlobalVariable &G : M.globals())
3442     writeModuleLevelReferences(G, NameVals, FSModRefsAbbrev);
3443 
3444   for (const GlobalAlias &A : M.aliases()) {
3445     auto *Aliasee = A.getBaseObject();
3446     if (!Aliasee->hasName())
3447       // Nameless function don't have an entry in the summary, skip it.
3448       continue;
3449     auto AliasId = VE.getValueID(&A);
3450     auto AliaseeId = VE.getValueID(Aliasee);
3451     NameVals.push_back(AliasId);
3452     auto *Summary = Index->getGlobalValueSummary(A);
3453     AliasSummary *AS = cast<AliasSummary>(Summary);
3454     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
3455     NameVals.push_back(AliaseeId);
3456     Stream.EmitRecord(bitc::FS_ALIAS, NameVals, FSAliasAbbrev);
3457     NameVals.clear();
3458   }
3459 
3460   Stream.ExitBlock();
3461 }
3462 
3463 /// Emit the combined summary section into the combined index file.
3464 void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
3465   Stream.EnterSubblock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID, 3);
3466   Stream.EmitRecord(bitc::FS_VERSION, ArrayRef<uint64_t>{INDEX_VERSION});
3467 
3468   // Abbrev for FS_COMBINED.
3469   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
3470   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED));
3471   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3472   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3473   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3474   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3475   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3476   // numrefs x valueid, n x (valueid)
3477   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3478   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3479   unsigned FSCallsAbbrev = Stream.EmitAbbrev(Abbv);
3480 
3481   // Abbrev for FS_COMBINED_PROFILE.
3482   Abbv = new BitCodeAbbrev();
3483   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_PROFILE));
3484   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3485   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3486   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3487   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3488   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3489   // numrefs x valueid, n x (valueid, hotness)
3490   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3491   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3492   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(Abbv);
3493 
3494   // Abbrev for FS_COMBINED_GLOBALVAR_INIT_REFS.
3495   Abbv = new BitCodeAbbrev();
3496   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS));
3497   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3498   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3499   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3500   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));    // valueids
3501   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3502   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(Abbv);
3503 
3504   // Abbrev for FS_COMBINED_ALIAS.
3505   Abbv = new BitCodeAbbrev();
3506   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_ALIAS));
3507   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3508   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3509   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3510   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3511   unsigned FSAliasAbbrev = Stream.EmitAbbrev(Abbv);
3512 
3513   // The aliases are emitted as a post-pass, and will point to the value
3514   // id of the aliasee. Save them in a vector for post-processing.
3515   SmallVector<AliasSummary *, 64> Aliases;
3516 
3517   // Save the value id for each summary for alias emission.
3518   DenseMap<const GlobalValueSummary *, unsigned> SummaryToValueIdMap;
3519 
3520   SmallVector<uint64_t, 64> NameVals;
3521 
3522   // For local linkage, we also emit the original name separately
3523   // immediately after the record.
3524   auto MaybeEmitOriginalName = [&](GlobalValueSummary &S) {
3525     if (!GlobalValue::isLocalLinkage(S.linkage()))
3526       return;
3527     NameVals.push_back(S.getOriginalName());
3528     Stream.EmitRecord(bitc::FS_COMBINED_ORIGINAL_NAME, NameVals);
3529     NameVals.clear();
3530   };
3531 
3532   for (const auto &I : *this) {
3533     GlobalValueSummary *S = I.second;
3534     assert(S);
3535 
3536     assert(hasValueId(I.first));
3537     unsigned ValueId = getValueId(I.first);
3538     SummaryToValueIdMap[S] = ValueId;
3539 
3540     if (auto *AS = dyn_cast<AliasSummary>(S)) {
3541       // Will process aliases as a post-pass because the reader wants all
3542       // global to be loaded first.
3543       Aliases.push_back(AS);
3544       continue;
3545     }
3546 
3547     if (auto *VS = dyn_cast<GlobalVarSummary>(S)) {
3548       NameVals.push_back(ValueId);
3549       NameVals.push_back(Index.getModuleId(VS->modulePath()));
3550       NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
3551       for (auto &RI : VS->refs()) {
3552         NameVals.push_back(getValueId(RI.getGUID()));
3553       }
3554 
3555       // Emit the finished record.
3556       Stream.EmitRecord(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS, NameVals,
3557                         FSModRefsAbbrev);
3558       NameVals.clear();
3559       MaybeEmitOriginalName(*S);
3560       continue;
3561     }
3562 
3563     auto *FS = cast<FunctionSummary>(S);
3564     NameVals.push_back(ValueId);
3565     NameVals.push_back(Index.getModuleId(FS->modulePath()));
3566     NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
3567     NameVals.push_back(FS->instCount());
3568     NameVals.push_back(FS->refs().size());
3569 
3570     for (auto &RI : FS->refs()) {
3571       NameVals.push_back(getValueId(RI.getGUID()));
3572     }
3573 
3574     bool HasProfileData = false;
3575     for (auto &EI : FS->calls()) {
3576       HasProfileData |= EI.second.Hotness != CalleeInfo::HotnessType::Unknown;
3577       if (HasProfileData)
3578         break;
3579     }
3580 
3581     for (auto &EI : FS->calls()) {
3582       // If this GUID doesn't have a value id, it doesn't have a function
3583       // summary and we don't need to record any calls to it.
3584       if (!hasValueId(EI.first.getGUID()))
3585         continue;
3586       NameVals.push_back(getValueId(EI.first.getGUID()));
3587       if (HasProfileData)
3588         NameVals.push_back(static_cast<uint8_t>(EI.second.Hotness));
3589     }
3590 
3591     unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
3592     unsigned Code =
3593         (HasProfileData ? bitc::FS_COMBINED_PROFILE : bitc::FS_COMBINED);
3594 
3595     // Emit the finished record.
3596     Stream.EmitRecord(Code, NameVals, FSAbbrev);
3597     NameVals.clear();
3598     MaybeEmitOriginalName(*S);
3599   }
3600 
3601   for (auto *AS : Aliases) {
3602     auto AliasValueId = SummaryToValueIdMap[AS];
3603     assert(AliasValueId);
3604     NameVals.push_back(AliasValueId);
3605     NameVals.push_back(Index.getModuleId(AS->modulePath()));
3606     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
3607     auto AliaseeValueId = SummaryToValueIdMap[&AS->getAliasee()];
3608     assert(AliaseeValueId);
3609     NameVals.push_back(AliaseeValueId);
3610 
3611     // Emit the finished record.
3612     Stream.EmitRecord(bitc::FS_COMBINED_ALIAS, NameVals, FSAliasAbbrev);
3613     NameVals.clear();
3614     MaybeEmitOriginalName(*AS);
3615   }
3616 
3617   Stream.ExitBlock();
3618 }
3619 
3620 void ModuleBitcodeWriter::writeIdentificationBlock() {
3621   Stream.EnterSubblock(bitc::IDENTIFICATION_BLOCK_ID, 5);
3622 
3623   // Write the "user readable" string identifying the bitcode producer
3624   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
3625   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_STRING));
3626   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3627   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3628   auto StringAbbrev = Stream.EmitAbbrev(Abbv);
3629   writeStringRecord(bitc::IDENTIFICATION_CODE_STRING,
3630                     "LLVM" LLVM_VERSION_STRING, StringAbbrev);
3631 
3632   // Write the epoch version
3633   Abbv = new BitCodeAbbrev();
3634   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_EPOCH));
3635   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
3636   auto EpochAbbrev = Stream.EmitAbbrev(Abbv);
3637   SmallVector<unsigned, 1> Vals = {bitc::BITCODE_CURRENT_EPOCH};
3638   Stream.EmitRecord(bitc::IDENTIFICATION_CODE_EPOCH, Vals, EpochAbbrev);
3639   Stream.ExitBlock();
3640 }
3641 
3642 void ModuleBitcodeWriter::writeModuleHash(size_t BlockStartPos) {
3643   // Emit the module's hash.
3644   // MODULE_CODE_HASH: [5*i32]
3645   SHA1 Hasher;
3646   Hasher.update(ArrayRef<uint8_t>((const uint8_t *)&(Buffer)[BlockStartPos],
3647                                   Buffer.size() - BlockStartPos));
3648   StringRef Hash = Hasher.result();
3649   uint32_t Vals[5];
3650   for (int Pos = 0; Pos < 20; Pos += 4) {
3651     Vals[Pos / 4] = support::endian::read32be(Hash.data() + Pos);
3652   }
3653 
3654   // Emit the finished record.
3655   Stream.EmitRecord(bitc::MODULE_CODE_HASH, Vals);
3656 }
3657 
3658 void BitcodeWriter::write() {
3659   // Emit the file header first.
3660   writeBitcodeHeader();
3661 
3662   writeBlocks();
3663 }
3664 
3665 void ModuleBitcodeWriter::writeBlocks() {
3666   writeIdentificationBlock();
3667   writeModule();
3668 }
3669 
3670 void IndexBitcodeWriter::writeBlocks() {
3671   // Index contains only a single outer (module) block.
3672   writeIndex();
3673 }
3674 
3675 void ModuleBitcodeWriter::writeModule() {
3676   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
3677   size_t BlockStartPos = Buffer.size();
3678 
3679   SmallVector<unsigned, 1> Vals;
3680   unsigned CurVersion = 1;
3681   Vals.push_back(CurVersion);
3682   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
3683 
3684   // Emit blockinfo, which defines the standard abbreviations etc.
3685   writeBlockInfo();
3686 
3687   // Emit information about attribute groups.
3688   writeAttributeGroupTable();
3689 
3690   // Emit information about parameter attributes.
3691   writeAttributeTable();
3692 
3693   // Emit information describing all of the types in the module.
3694   writeTypeTable();
3695 
3696   writeComdats();
3697 
3698   // Emit top-level description of module, including target triple, inline asm,
3699   // descriptors for global variables, and function prototype info.
3700   writeModuleInfo();
3701 
3702   // Emit constants.
3703   writeModuleConstants();
3704 
3705   // Emit metadata kind names.
3706   writeModuleMetadataKinds();
3707 
3708   // Emit metadata.
3709   writeModuleMetadata();
3710 
3711   // Emit module-level use-lists.
3712   if (VE.shouldPreserveUseListOrder())
3713     writeUseListBlock(nullptr);
3714 
3715   writeOperandBundleTags();
3716 
3717   // Emit function bodies.
3718   DenseMap<const Function *, uint64_t> FunctionToBitcodeIndex;
3719   for (Module::const_iterator F = M.begin(), E = M.end(); F != E; ++F)
3720     if (!F->isDeclaration())
3721       writeFunction(*F, FunctionToBitcodeIndex);
3722 
3723   // Need to write after the above call to WriteFunction which populates
3724   // the summary information in the index.
3725   if (Index)
3726     writePerModuleGlobalValueSummary();
3727 
3728   writeValueSymbolTable(M.getValueSymbolTable(),
3729                         /* IsModuleLevel */ true, &FunctionToBitcodeIndex);
3730 
3731   if (GenerateHash) {
3732     writeModuleHash(BlockStartPos);
3733   }
3734 
3735   Stream.ExitBlock();
3736 }
3737 
3738 static void writeInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
3739                                uint32_t &Position) {
3740   support::endian::write32le(&Buffer[Position], Value);
3741   Position += 4;
3742 }
3743 
3744 /// If generating a bc file on darwin, we have to emit a
3745 /// header and trailer to make it compatible with the system archiver.  To do
3746 /// this we emit the following header, and then emit a trailer that pads the
3747 /// file out to be a multiple of 16 bytes.
3748 ///
3749 /// struct bc_header {
3750 ///   uint32_t Magic;         // 0x0B17C0DE
3751 ///   uint32_t Version;       // Version, currently always 0.
3752 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
3753 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
3754 ///   uint32_t CPUType;       // CPU specifier.
3755 ///   ... potentially more later ...
3756 /// };
3757 static void emitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
3758                                          const Triple &TT) {
3759   unsigned CPUType = ~0U;
3760 
3761   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
3762   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
3763   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
3764   // specific constants here because they are implicitly part of the Darwin ABI.
3765   enum {
3766     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
3767     DARWIN_CPU_TYPE_X86        = 7,
3768     DARWIN_CPU_TYPE_ARM        = 12,
3769     DARWIN_CPU_TYPE_POWERPC    = 18
3770   };
3771 
3772   Triple::ArchType Arch = TT.getArch();
3773   if (Arch == Triple::x86_64)
3774     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
3775   else if (Arch == Triple::x86)
3776     CPUType = DARWIN_CPU_TYPE_X86;
3777   else if (Arch == Triple::ppc)
3778     CPUType = DARWIN_CPU_TYPE_POWERPC;
3779   else if (Arch == Triple::ppc64)
3780     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
3781   else if (Arch == Triple::arm || Arch == Triple::thumb)
3782     CPUType = DARWIN_CPU_TYPE_ARM;
3783 
3784   // Traditional Bitcode starts after header.
3785   assert(Buffer.size() >= BWH_HeaderSize &&
3786          "Expected header size to be reserved");
3787   unsigned BCOffset = BWH_HeaderSize;
3788   unsigned BCSize = Buffer.size() - BWH_HeaderSize;
3789 
3790   // Write the magic and version.
3791   unsigned Position = 0;
3792   writeInt32ToBuffer(0x0B17C0DE, Buffer, Position);
3793   writeInt32ToBuffer(0, Buffer, Position); // Version.
3794   writeInt32ToBuffer(BCOffset, Buffer, Position);
3795   writeInt32ToBuffer(BCSize, Buffer, Position);
3796   writeInt32ToBuffer(CPUType, Buffer, Position);
3797 
3798   // If the file is not a multiple of 16 bytes, insert dummy padding.
3799   while (Buffer.size() & 15)
3800     Buffer.push_back(0);
3801 }
3802 
3803 /// Helper to write the header common to all bitcode files.
3804 void BitcodeWriter::writeBitcodeHeader() {
3805   // Emit the file header.
3806   Stream.Emit((unsigned)'B', 8);
3807   Stream.Emit((unsigned)'C', 8);
3808   Stream.Emit(0x0, 4);
3809   Stream.Emit(0xC, 4);
3810   Stream.Emit(0xE, 4);
3811   Stream.Emit(0xD, 4);
3812 }
3813 
3814 /// WriteBitcodeToFile - Write the specified module to the specified output
3815 /// stream.
3816 void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out,
3817                               bool ShouldPreserveUseListOrder,
3818                               const ModuleSummaryIndex *Index,
3819                               bool GenerateHash) {
3820   SmallVector<char, 0> Buffer;
3821   Buffer.reserve(256*1024);
3822 
3823   // If this is darwin or another generic macho target, reserve space for the
3824   // header.
3825   Triple TT(M->getTargetTriple());
3826   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
3827     Buffer.insert(Buffer.begin(), BWH_HeaderSize, 0);
3828 
3829   // Emit the module into the buffer.
3830   ModuleBitcodeWriter ModuleWriter(M, Buffer, ShouldPreserveUseListOrder, Index,
3831                                    GenerateHash);
3832   ModuleWriter.write();
3833 
3834   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
3835     emitDarwinBCHeaderAndTrailer(Buffer, TT);
3836 
3837   // Write the generated bitstream to "Out".
3838   Out.write((char*)&Buffer.front(), Buffer.size());
3839 }
3840 
3841 void IndexBitcodeWriter::writeIndex() {
3842   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
3843 
3844   SmallVector<unsigned, 1> Vals;
3845   unsigned CurVersion = 1;
3846   Vals.push_back(CurVersion);
3847   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
3848 
3849   // If we have a VST, write the VSTOFFSET record placeholder.
3850   writeValueSymbolTableForwardDecl();
3851 
3852   // Write the module paths in the combined index.
3853   writeModStrings();
3854 
3855   // Write the summary combined index records.
3856   writeCombinedGlobalValueSummary();
3857 
3858   // Need a special VST writer for the combined index (we don't have a
3859   // real VST and real values when this is invoked).
3860   writeCombinedValueSymbolTable();
3861 
3862   Stream.ExitBlock();
3863 }
3864 
3865 // Write the specified module summary index to the given raw output stream,
3866 // where it will be written in a new bitcode block. This is used when
3867 // writing the combined index file for ThinLTO. When writing a subset of the
3868 // index for a distributed backend, provide a \p ModuleToSummariesForIndex map.
3869 void llvm::WriteIndexToFile(
3870     const ModuleSummaryIndex &Index, raw_ostream &Out,
3871     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
3872   SmallVector<char, 0> Buffer;
3873   Buffer.reserve(256 * 1024);
3874 
3875   IndexBitcodeWriter IndexWriter(Buffer, Index, ModuleToSummariesForIndex);
3876   IndexWriter.write();
3877 
3878   Out.write((char *)&Buffer.front(), Buffer.size());
3879 }
3880