xref: /llvm-project/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp (revision 519465b993268b5b07b676a5224d858169507f1b)
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 
42 cl::opt<unsigned>
43     IndexThreshold("bitcode-mdindex-threshold", cl::Hidden, cl::init(25),
44                    cl::desc("Number of metadatas above which we emit an index "
45                             "to enable lazy-loading"));
46 /// These are manifest constants used by the bitcode writer. They do not need to
47 /// be kept in sync with the reader, but need to be consistent within this file.
48 enum {
49   // VALUE_SYMTAB_BLOCK abbrev id's.
50   VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
51   VST_ENTRY_7_ABBREV,
52   VST_ENTRY_6_ABBREV,
53   VST_BBENTRY_6_ABBREV,
54 
55   // CONSTANTS_BLOCK abbrev id's.
56   CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
57   CONSTANTS_INTEGER_ABBREV,
58   CONSTANTS_CE_CAST_Abbrev,
59   CONSTANTS_NULL_Abbrev,
60 
61   // FUNCTION_BLOCK abbrev id's.
62   FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
63   FUNCTION_INST_BINOP_ABBREV,
64   FUNCTION_INST_BINOP_FLAGS_ABBREV,
65   FUNCTION_INST_CAST_ABBREV,
66   FUNCTION_INST_RET_VOID_ABBREV,
67   FUNCTION_INST_RET_VAL_ABBREV,
68   FUNCTION_INST_UNREACHABLE_ABBREV,
69   FUNCTION_INST_GEP_ABBREV,
70 };
71 
72 /// Abstract class to manage the bitcode writing, subclassed for each bitcode
73 /// file type.
74 class BitcodeWriterBase {
75 protected:
76   /// The stream created and owned by the client.
77   BitstreamWriter &Stream;
78 
79   /// Saves the offset of the VSTOffset record that must eventually be
80   /// backpatched with the offset of the actual VST.
81   uint64_t VSTOffsetPlaceholder = 0;
82 
83 public:
84   /// Constructs a BitcodeWriterBase object that writes to the provided
85   /// \p Stream.
86   BitcodeWriterBase(BitstreamWriter &Stream) : Stream(Stream) {}
87 
88 protected:
89   bool hasVSTOffsetPlaceholder() { return VSTOffsetPlaceholder != 0; }
90   void writeValueSymbolTableForwardDecl();
91   void writeBitcodeHeader();
92 };
93 
94 /// Class to manage the bitcode writing for a module.
95 class ModuleBitcodeWriter : public BitcodeWriterBase {
96   /// Pointer to the buffer allocated by caller for bitcode writing.
97   const SmallVectorImpl<char> &Buffer;
98 
99   /// The Module to write to bitcode.
100   const Module &M;
101 
102   /// Enumerates ids for all values in the module.
103   ValueEnumerator VE;
104 
105   /// Optional per-module index to write for ThinLTO.
106   const ModuleSummaryIndex *Index;
107 
108   /// True if a module hash record should be written.
109   bool GenerateHash;
110 
111   /// The start bit of the identification block.
112   uint64_t BitcodeStartBit;
113 
114   /// Map that holds the correspondence between GUIDs in the summary index,
115   /// that came from indirect call profiles, and a value id generated by this
116   /// class to use in the VST and summary block records.
117   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
118 
119   /// Tracks the last value id recorded in the GUIDToValueMap.
120   unsigned GlobalValueId;
121 
122 public:
123   /// Constructs a ModuleBitcodeWriter object for the given Module,
124   /// writing to the provided \p Buffer.
125   ModuleBitcodeWriter(const Module *M, SmallVectorImpl<char> &Buffer,
126                       BitstreamWriter &Stream, bool ShouldPreserveUseListOrder,
127                       const ModuleSummaryIndex *Index, bool GenerateHash)
128       : BitcodeWriterBase(Stream), Buffer(Buffer), M(*M),
129         VE(*M, ShouldPreserveUseListOrder), Index(Index),
130         GenerateHash(GenerateHash), BitcodeStartBit(Stream.GetCurrentBitNo()) {
131     // Assign ValueIds to any callee values in the index that came from
132     // indirect call profiles and were recorded as a GUID not a Value*
133     // (which would have been assigned an ID by the ValueEnumerator).
134     // The starting ValueId is just after the number of values in the
135     // ValueEnumerator, so that they can be emitted in the VST.
136     GlobalValueId = VE.getValues().size();
137     if (!Index)
138       return;
139     for (const auto &GUIDSummaryLists : *Index)
140       // Examine all summaries for this GUID.
141       for (auto &Summary : GUIDSummaryLists.second)
142         if (auto FS = dyn_cast<FunctionSummary>(Summary.get()))
143           // For each call in the function summary, see if the call
144           // is to a GUID (which means it is for an indirect call,
145           // otherwise we would have a Value for it). If so, synthesize
146           // a value id.
147           for (auto &CallEdge : FS->calls())
148             if (CallEdge.first.isGUID())
149               assignValueId(CallEdge.first.getGUID());
150   }
151 
152   /// Emit the current module to the bitstream.
153   void write();
154 
155 private:
156   uint64_t bitcodeStartBit() { return BitcodeStartBit; }
157 
158   void writeAttributeGroupTable();
159   void writeAttributeTable();
160   void writeTypeTable();
161   void writeComdats();
162   void writeModuleInfo();
163   void writeValueAsMetadata(const ValueAsMetadata *MD,
164                             SmallVectorImpl<uint64_t> &Record);
165   void writeMDTuple(const MDTuple *N, SmallVectorImpl<uint64_t> &Record,
166                     unsigned Abbrev);
167   unsigned createDILocationAbbrev();
168   void writeDILocation(const DILocation *N, SmallVectorImpl<uint64_t> &Record,
169                        unsigned &Abbrev);
170   unsigned createGenericDINodeAbbrev();
171   void writeGenericDINode(const GenericDINode *N,
172                           SmallVectorImpl<uint64_t> &Record, unsigned &Abbrev);
173   void writeDISubrange(const DISubrange *N, SmallVectorImpl<uint64_t> &Record,
174                        unsigned Abbrev);
175   void writeDIEnumerator(const DIEnumerator *N,
176                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
177   void writeDIBasicType(const DIBasicType *N, SmallVectorImpl<uint64_t> &Record,
178                         unsigned Abbrev);
179   void writeDIDerivedType(const DIDerivedType *N,
180                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
181   void writeDICompositeType(const DICompositeType *N,
182                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
183   void writeDISubroutineType(const DISubroutineType *N,
184                              SmallVectorImpl<uint64_t> &Record,
185                              unsigned Abbrev);
186   void writeDIFile(const DIFile *N, SmallVectorImpl<uint64_t> &Record,
187                    unsigned Abbrev);
188   void writeDICompileUnit(const DICompileUnit *N,
189                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
190   void writeDISubprogram(const DISubprogram *N,
191                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
192   void writeDILexicalBlock(const DILexicalBlock *N,
193                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
194   void writeDILexicalBlockFile(const DILexicalBlockFile *N,
195                                SmallVectorImpl<uint64_t> &Record,
196                                unsigned Abbrev);
197   void writeDINamespace(const DINamespace *N, SmallVectorImpl<uint64_t> &Record,
198                         unsigned Abbrev);
199   void writeDIMacro(const DIMacro *N, SmallVectorImpl<uint64_t> &Record,
200                     unsigned Abbrev);
201   void writeDIMacroFile(const DIMacroFile *N, SmallVectorImpl<uint64_t> &Record,
202                         unsigned Abbrev);
203   void writeDIModule(const DIModule *N, SmallVectorImpl<uint64_t> &Record,
204                      unsigned Abbrev);
205   void writeDITemplateTypeParameter(const DITemplateTypeParameter *N,
206                                     SmallVectorImpl<uint64_t> &Record,
207                                     unsigned Abbrev);
208   void writeDITemplateValueParameter(const DITemplateValueParameter *N,
209                                      SmallVectorImpl<uint64_t> &Record,
210                                      unsigned Abbrev);
211   void writeDIGlobalVariable(const DIGlobalVariable *N,
212                              SmallVectorImpl<uint64_t> &Record,
213                              unsigned Abbrev);
214   void writeDILocalVariable(const DILocalVariable *N,
215                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
216   void writeDIExpression(const DIExpression *N,
217                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
218   void writeDIGlobalVariableExpression(const DIGlobalVariableExpression *N,
219                                        SmallVectorImpl<uint64_t> &Record,
220                                        unsigned Abbrev);
221   void writeDIObjCProperty(const DIObjCProperty *N,
222                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
223   void writeDIImportedEntity(const DIImportedEntity *N,
224                              SmallVectorImpl<uint64_t> &Record,
225                              unsigned Abbrev);
226   unsigned createNamedMetadataAbbrev();
227   void writeNamedMetadata(SmallVectorImpl<uint64_t> &Record);
228   unsigned createMetadataStringsAbbrev();
229   void writeMetadataStrings(ArrayRef<const Metadata *> Strings,
230                             SmallVectorImpl<uint64_t> &Record);
231   void writeMetadataRecords(ArrayRef<const Metadata *> MDs,
232                             SmallVectorImpl<uint64_t> &Record,
233                             std::vector<unsigned> *MDAbbrevs = nullptr,
234                             std::vector<uint64_t> *IndexPos = nullptr);
235   void writeModuleMetadata();
236   void writeFunctionMetadata(const Function &F);
237   void writeFunctionMetadataAttachment(const Function &F);
238   void writeGlobalVariableMetadataAttachment(const GlobalVariable &GV);
239   void pushGlobalMetadataAttachment(SmallVectorImpl<uint64_t> &Record,
240                                     const GlobalObject &GO);
241   void writeModuleMetadataKinds();
242   void writeOperandBundleTags();
243   void writeConstants(unsigned FirstVal, unsigned LastVal, bool isGlobal);
244   void writeModuleConstants();
245   bool pushValueAndType(const Value *V, unsigned InstID,
246                         SmallVectorImpl<unsigned> &Vals);
247   void writeOperandBundles(ImmutableCallSite CS, unsigned InstID);
248   void pushValue(const Value *V, unsigned InstID,
249                  SmallVectorImpl<unsigned> &Vals);
250   void pushValueSigned(const Value *V, unsigned InstID,
251                        SmallVectorImpl<uint64_t> &Vals);
252   void writeInstruction(const Instruction &I, unsigned InstID,
253                         SmallVectorImpl<unsigned> &Vals);
254   void writeValueSymbolTable(
255       const ValueSymbolTable &VST, bool IsModuleLevel = false,
256       DenseMap<const Function *, uint64_t> *FunctionToBitcodeIndex = nullptr);
257   void writeUseList(UseListOrder &&Order);
258   void writeUseListBlock(const Function *F);
259   void
260   writeFunction(const Function &F,
261                 DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
262   void writeBlockInfo();
263   void writePerModuleFunctionSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
264                                            GlobalValueSummary *Summary,
265                                            unsigned ValueID,
266                                            unsigned FSCallsAbbrev,
267                                            unsigned FSCallsProfileAbbrev,
268                                            const Function &F);
269   void writeModuleLevelReferences(const GlobalVariable &V,
270                                   SmallVector<uint64_t, 64> &NameVals,
271                                   unsigned FSModRefsAbbrev);
272   void writePerModuleGlobalValueSummary();
273   void writeModuleHash(size_t BlockStartPos);
274 
275   void assignValueId(GlobalValue::GUID ValGUID) {
276     GUIDToValueIdMap[ValGUID] = ++GlobalValueId;
277   }
278   unsigned getValueId(GlobalValue::GUID ValGUID) {
279     const auto &VMI = GUIDToValueIdMap.find(ValGUID);
280     // Expect that any GUID value had a value Id assigned by an
281     // earlier call to assignValueId.
282     assert(VMI != GUIDToValueIdMap.end() &&
283            "GUID does not have assigned value Id");
284     return VMI->second;
285   }
286   // Helper to get the valueId for the type of value recorded in VI.
287   unsigned getValueId(ValueInfo VI) {
288     if (VI.isGUID())
289       return getValueId(VI.getGUID());
290     return VE.getValueID(VI.getValue());
291   }
292   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
293 };
294 
295 /// Class to manage the bitcode writing for a combined index.
296 class IndexBitcodeWriter : public BitcodeWriterBase {
297   /// The combined index to write to bitcode.
298   const ModuleSummaryIndex &Index;
299 
300   /// When writing a subset of the index for distributed backends, client
301   /// provides a map of modules to the corresponding GUIDs/summaries to write.
302   const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex;
303 
304   /// Map that holds the correspondence between the GUID used in the combined
305   /// index and a value id generated by this class to use in references.
306   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
307 
308   /// Tracks the last value id recorded in the GUIDToValueMap.
309   unsigned GlobalValueId = 0;
310 
311 public:
312   /// Constructs a IndexBitcodeWriter object for the given combined index,
313   /// writing to the provided \p Buffer. When writing a subset of the index
314   /// for a distributed backend, provide a \p ModuleToSummariesForIndex map.
315   IndexBitcodeWriter(BitstreamWriter &Stream, const ModuleSummaryIndex &Index,
316                      const std::map<std::string, GVSummaryMapTy>
317                          *ModuleToSummariesForIndex = nullptr)
318       : BitcodeWriterBase(Stream), Index(Index),
319         ModuleToSummariesForIndex(ModuleToSummariesForIndex) {
320     // Assign unique value ids to all summaries to be written, for use
321     // in writing out the call graph edges. Save the mapping from GUID
322     // to the new global value id to use when writing those edges, which
323     // are currently saved in the index in terms of GUID.
324     for (const auto &I : *this)
325       GUIDToValueIdMap[I.first] = ++GlobalValueId;
326   }
327 
328   /// The below iterator returns the GUID and associated summary.
329   typedef std::pair<GlobalValue::GUID, GlobalValueSummary *> GVInfo;
330 
331   /// Iterator over the value GUID and summaries to be written to bitcode,
332   /// hides the details of whether they are being pulled from the entire
333   /// index or just those in a provided ModuleToSummariesForIndex map.
334   class iterator
335       : public llvm::iterator_facade_base<iterator, std::forward_iterator_tag,
336                                           GVInfo> {
337     /// Enables access to parent class.
338     const IndexBitcodeWriter &Writer;
339 
340     // Iterators used when writing only those summaries in a provided
341     // ModuleToSummariesForIndex map:
342 
343     /// Points to the last element in outer ModuleToSummariesForIndex map.
344     std::map<std::string, GVSummaryMapTy>::const_iterator ModuleSummariesBack;
345     /// Iterator on outer ModuleToSummariesForIndex map.
346     std::map<std::string, GVSummaryMapTy>::const_iterator ModuleSummariesIter;
347     /// Iterator on an inner global variable summary map.
348     GVSummaryMapTy::const_iterator ModuleGVSummariesIter;
349 
350     // Iterators used when writing all summaries in the index:
351 
352     /// Points to the last element in the Index outer GlobalValueMap.
353     const_gvsummary_iterator IndexSummariesBack;
354     /// Iterator on outer GlobalValueMap.
355     const_gvsummary_iterator IndexSummariesIter;
356     /// Iterator on an inner GlobalValueSummaryList.
357     GlobalValueSummaryList::const_iterator IndexGVSummariesIter;
358 
359   public:
360     /// Construct iterator from parent \p Writer and indicate if we are
361     /// constructing the end iterator.
362     iterator(const IndexBitcodeWriter &Writer, bool IsAtEnd) : Writer(Writer) {
363       // Set up the appropriate set of iterators given whether we are writing
364       // the full index or just a subset.
365       // Can't setup the Back or inner iterators if the corresponding map
366       // is empty. This will be handled specially in operator== as well.
367       if (Writer.ModuleToSummariesForIndex &&
368           !Writer.ModuleToSummariesForIndex->empty()) {
369         for (ModuleSummariesBack = Writer.ModuleToSummariesForIndex->begin();
370              std::next(ModuleSummariesBack) !=
371              Writer.ModuleToSummariesForIndex->end();
372              ModuleSummariesBack++)
373           ;
374         ModuleSummariesIter = !IsAtEnd
375                                   ? Writer.ModuleToSummariesForIndex->begin()
376                                   : ModuleSummariesBack;
377         ModuleGVSummariesIter = !IsAtEnd ? ModuleSummariesIter->second.begin()
378                                          : ModuleSummariesBack->second.end();
379       } else if (!Writer.ModuleToSummariesForIndex &&
380                  Writer.Index.begin() != Writer.Index.end()) {
381         for (IndexSummariesBack = Writer.Index.begin();
382              std::next(IndexSummariesBack) != Writer.Index.end();
383              IndexSummariesBack++)
384           ;
385         IndexSummariesIter =
386             !IsAtEnd ? Writer.Index.begin() : IndexSummariesBack;
387         IndexGVSummariesIter = !IsAtEnd ? IndexSummariesIter->second.begin()
388                                         : IndexSummariesBack->second.end();
389       }
390     }
391 
392     /// Increment the appropriate set of iterators.
393     iterator &operator++() {
394       // First the inner iterator is incremented, then if it is at the end
395       // and there are more outer iterations to go, the inner is reset to
396       // the start of the next inner list.
397       if (Writer.ModuleToSummariesForIndex) {
398         ++ModuleGVSummariesIter;
399         if (ModuleGVSummariesIter == ModuleSummariesIter->second.end() &&
400             ModuleSummariesIter != ModuleSummariesBack) {
401           ++ModuleSummariesIter;
402           ModuleGVSummariesIter = ModuleSummariesIter->second.begin();
403         }
404       } else {
405         ++IndexGVSummariesIter;
406         if (IndexGVSummariesIter == IndexSummariesIter->second.end() &&
407             IndexSummariesIter != IndexSummariesBack) {
408           ++IndexSummariesIter;
409           IndexGVSummariesIter = IndexSummariesIter->second.begin();
410         }
411       }
412       return *this;
413     }
414 
415     /// Access the <GUID,GlobalValueSummary*> pair corresponding to the current
416     /// outer and inner iterator positions.
417     GVInfo operator*() {
418       if (Writer.ModuleToSummariesForIndex)
419         return std::make_pair(ModuleGVSummariesIter->first,
420                               ModuleGVSummariesIter->second);
421       return std::make_pair(IndexSummariesIter->first,
422                             IndexGVSummariesIter->get());
423     }
424 
425     /// Checks if the iterators are equal, with special handling for empty
426     /// indexes.
427     bool operator==(const iterator &RHS) const {
428       if (Writer.ModuleToSummariesForIndex) {
429         // First ensure that both are writing the same subset.
430         if (Writer.ModuleToSummariesForIndex !=
431             RHS.Writer.ModuleToSummariesForIndex)
432           return false;
433         // Already determined above that maps are the same, so if one is
434         // empty, they both are.
435         if (Writer.ModuleToSummariesForIndex->empty())
436           return true;
437         // Ensure the ModuleGVSummariesIter are iterating over the same
438         // container before checking them below.
439         if (ModuleSummariesIter != RHS.ModuleSummariesIter)
440           return false;
441         return ModuleGVSummariesIter == RHS.ModuleGVSummariesIter;
442       }
443       // First ensure RHS also writing the full index, and that both are
444       // writing the same full index.
445       if (RHS.Writer.ModuleToSummariesForIndex ||
446           &Writer.Index != &RHS.Writer.Index)
447         return false;
448       // Already determined above that maps are the same, so if one is
449       // empty, they both are.
450       if (Writer.Index.begin() == Writer.Index.end())
451         return true;
452       // Ensure the IndexGVSummariesIter are iterating over the same
453       // container before checking them below.
454       if (IndexSummariesIter != RHS.IndexSummariesIter)
455         return false;
456       return IndexGVSummariesIter == RHS.IndexGVSummariesIter;
457     }
458   };
459 
460   /// Obtain the start iterator over the summaries to be written.
461   iterator begin() { return iterator(*this, /*IsAtEnd=*/false); }
462   /// Obtain the end iterator over the summaries to be written.
463   iterator end() { return iterator(*this, /*IsAtEnd=*/true); }
464 
465   /// Main entry point for writing a combined index to bitcode.
466   void write();
467 
468 private:
469   void writeIndex();
470   void writeModStrings();
471   void writeCombinedValueSymbolTable();
472   void writeCombinedGlobalValueSummary();
473 
474   /// Indicates whether the provided \p ModulePath should be written into
475   /// the module string table, e.g. if full index written or if it is in
476   /// the provided subset.
477   bool doIncludeModule(StringRef ModulePath) {
478     return !ModuleToSummariesForIndex ||
479            ModuleToSummariesForIndex->count(ModulePath);
480   }
481 
482   bool hasValueId(GlobalValue::GUID ValGUID) {
483     const auto &VMI = GUIDToValueIdMap.find(ValGUID);
484     return VMI != GUIDToValueIdMap.end();
485   }
486   unsigned getValueId(GlobalValue::GUID ValGUID) {
487     const auto &VMI = GUIDToValueIdMap.find(ValGUID);
488     // If this GUID doesn't have an entry, assign one.
489     if (VMI == GUIDToValueIdMap.end()) {
490       GUIDToValueIdMap[ValGUID] = ++GlobalValueId;
491       return GlobalValueId;
492     } else {
493       return VMI->second;
494     }
495   }
496   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
497 };
498 } // end anonymous namespace
499 
500 static unsigned getEncodedCastOpcode(unsigned Opcode) {
501   switch (Opcode) {
502   default: llvm_unreachable("Unknown cast instruction!");
503   case Instruction::Trunc   : return bitc::CAST_TRUNC;
504   case Instruction::ZExt    : return bitc::CAST_ZEXT;
505   case Instruction::SExt    : return bitc::CAST_SEXT;
506   case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
507   case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
508   case Instruction::UIToFP  : return bitc::CAST_UITOFP;
509   case Instruction::SIToFP  : return bitc::CAST_SITOFP;
510   case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
511   case Instruction::FPExt   : return bitc::CAST_FPEXT;
512   case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
513   case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
514   case Instruction::BitCast : return bitc::CAST_BITCAST;
515   case Instruction::AddrSpaceCast: return bitc::CAST_ADDRSPACECAST;
516   }
517 }
518 
519 static unsigned getEncodedBinaryOpcode(unsigned Opcode) {
520   switch (Opcode) {
521   default: llvm_unreachable("Unknown binary instruction!");
522   case Instruction::Add:
523   case Instruction::FAdd: return bitc::BINOP_ADD;
524   case Instruction::Sub:
525   case Instruction::FSub: return bitc::BINOP_SUB;
526   case Instruction::Mul:
527   case Instruction::FMul: return bitc::BINOP_MUL;
528   case Instruction::UDiv: return bitc::BINOP_UDIV;
529   case Instruction::FDiv:
530   case Instruction::SDiv: return bitc::BINOP_SDIV;
531   case Instruction::URem: return bitc::BINOP_UREM;
532   case Instruction::FRem:
533   case Instruction::SRem: return bitc::BINOP_SREM;
534   case Instruction::Shl:  return bitc::BINOP_SHL;
535   case Instruction::LShr: return bitc::BINOP_LSHR;
536   case Instruction::AShr: return bitc::BINOP_ASHR;
537   case Instruction::And:  return bitc::BINOP_AND;
538   case Instruction::Or:   return bitc::BINOP_OR;
539   case Instruction::Xor:  return bitc::BINOP_XOR;
540   }
541 }
542 
543 static unsigned getEncodedRMWOperation(AtomicRMWInst::BinOp Op) {
544   switch (Op) {
545   default: llvm_unreachable("Unknown RMW operation!");
546   case AtomicRMWInst::Xchg: return bitc::RMW_XCHG;
547   case AtomicRMWInst::Add: return bitc::RMW_ADD;
548   case AtomicRMWInst::Sub: return bitc::RMW_SUB;
549   case AtomicRMWInst::And: return bitc::RMW_AND;
550   case AtomicRMWInst::Nand: return bitc::RMW_NAND;
551   case AtomicRMWInst::Or: return bitc::RMW_OR;
552   case AtomicRMWInst::Xor: return bitc::RMW_XOR;
553   case AtomicRMWInst::Max: return bitc::RMW_MAX;
554   case AtomicRMWInst::Min: return bitc::RMW_MIN;
555   case AtomicRMWInst::UMax: return bitc::RMW_UMAX;
556   case AtomicRMWInst::UMin: return bitc::RMW_UMIN;
557   }
558 }
559 
560 static unsigned getEncodedOrdering(AtomicOrdering Ordering) {
561   switch (Ordering) {
562   case AtomicOrdering::NotAtomic: return bitc::ORDERING_NOTATOMIC;
563   case AtomicOrdering::Unordered: return bitc::ORDERING_UNORDERED;
564   case AtomicOrdering::Monotonic: return bitc::ORDERING_MONOTONIC;
565   case AtomicOrdering::Acquire: return bitc::ORDERING_ACQUIRE;
566   case AtomicOrdering::Release: return bitc::ORDERING_RELEASE;
567   case AtomicOrdering::AcquireRelease: return bitc::ORDERING_ACQREL;
568   case AtomicOrdering::SequentiallyConsistent: return bitc::ORDERING_SEQCST;
569   }
570   llvm_unreachable("Invalid ordering");
571 }
572 
573 static unsigned getEncodedSynchScope(SynchronizationScope SynchScope) {
574   switch (SynchScope) {
575   case SingleThread: return bitc::SYNCHSCOPE_SINGLETHREAD;
576   case CrossThread: return bitc::SYNCHSCOPE_CROSSTHREAD;
577   }
578   llvm_unreachable("Invalid synch scope");
579 }
580 
581 static void writeStringRecord(BitstreamWriter &Stream, unsigned Code,
582                               StringRef Str, unsigned AbbrevToUse) {
583   SmallVector<unsigned, 64> Vals;
584 
585   // Code: [strchar x N]
586   for (unsigned i = 0, e = Str.size(); i != e; ++i) {
587     if (AbbrevToUse && !BitCodeAbbrevOp::isChar6(Str[i]))
588       AbbrevToUse = 0;
589     Vals.push_back(Str[i]);
590   }
591 
592   // Emit the finished record.
593   Stream.EmitRecord(Code, Vals, AbbrevToUse);
594 }
595 
596 static uint64_t getAttrKindEncoding(Attribute::AttrKind Kind) {
597   switch (Kind) {
598   case Attribute::Alignment:
599     return bitc::ATTR_KIND_ALIGNMENT;
600   case Attribute::AllocSize:
601     return bitc::ATTR_KIND_ALLOC_SIZE;
602   case Attribute::AlwaysInline:
603     return bitc::ATTR_KIND_ALWAYS_INLINE;
604   case Attribute::ArgMemOnly:
605     return bitc::ATTR_KIND_ARGMEMONLY;
606   case Attribute::Builtin:
607     return bitc::ATTR_KIND_BUILTIN;
608   case Attribute::ByVal:
609     return bitc::ATTR_KIND_BY_VAL;
610   case Attribute::Convergent:
611     return bitc::ATTR_KIND_CONVERGENT;
612   case Attribute::InAlloca:
613     return bitc::ATTR_KIND_IN_ALLOCA;
614   case Attribute::Cold:
615     return bitc::ATTR_KIND_COLD;
616   case Attribute::InaccessibleMemOnly:
617     return bitc::ATTR_KIND_INACCESSIBLEMEM_ONLY;
618   case Attribute::InaccessibleMemOrArgMemOnly:
619     return bitc::ATTR_KIND_INACCESSIBLEMEM_OR_ARGMEMONLY;
620   case Attribute::InlineHint:
621     return bitc::ATTR_KIND_INLINE_HINT;
622   case Attribute::InReg:
623     return bitc::ATTR_KIND_IN_REG;
624   case Attribute::JumpTable:
625     return bitc::ATTR_KIND_JUMP_TABLE;
626   case Attribute::MinSize:
627     return bitc::ATTR_KIND_MIN_SIZE;
628   case Attribute::Naked:
629     return bitc::ATTR_KIND_NAKED;
630   case Attribute::Nest:
631     return bitc::ATTR_KIND_NEST;
632   case Attribute::NoAlias:
633     return bitc::ATTR_KIND_NO_ALIAS;
634   case Attribute::NoBuiltin:
635     return bitc::ATTR_KIND_NO_BUILTIN;
636   case Attribute::NoCapture:
637     return bitc::ATTR_KIND_NO_CAPTURE;
638   case Attribute::NoDuplicate:
639     return bitc::ATTR_KIND_NO_DUPLICATE;
640   case Attribute::NoImplicitFloat:
641     return bitc::ATTR_KIND_NO_IMPLICIT_FLOAT;
642   case Attribute::NoInline:
643     return bitc::ATTR_KIND_NO_INLINE;
644   case Attribute::NoRecurse:
645     return bitc::ATTR_KIND_NO_RECURSE;
646   case Attribute::NonLazyBind:
647     return bitc::ATTR_KIND_NON_LAZY_BIND;
648   case Attribute::NonNull:
649     return bitc::ATTR_KIND_NON_NULL;
650   case Attribute::Dereferenceable:
651     return bitc::ATTR_KIND_DEREFERENCEABLE;
652   case Attribute::DereferenceableOrNull:
653     return bitc::ATTR_KIND_DEREFERENCEABLE_OR_NULL;
654   case Attribute::NoRedZone:
655     return bitc::ATTR_KIND_NO_RED_ZONE;
656   case Attribute::NoReturn:
657     return bitc::ATTR_KIND_NO_RETURN;
658   case Attribute::NoUnwind:
659     return bitc::ATTR_KIND_NO_UNWIND;
660   case Attribute::OptimizeForSize:
661     return bitc::ATTR_KIND_OPTIMIZE_FOR_SIZE;
662   case Attribute::OptimizeNone:
663     return bitc::ATTR_KIND_OPTIMIZE_NONE;
664   case Attribute::ReadNone:
665     return bitc::ATTR_KIND_READ_NONE;
666   case Attribute::ReadOnly:
667     return bitc::ATTR_KIND_READ_ONLY;
668   case Attribute::Returned:
669     return bitc::ATTR_KIND_RETURNED;
670   case Attribute::ReturnsTwice:
671     return bitc::ATTR_KIND_RETURNS_TWICE;
672   case Attribute::SExt:
673     return bitc::ATTR_KIND_S_EXT;
674   case Attribute::StackAlignment:
675     return bitc::ATTR_KIND_STACK_ALIGNMENT;
676   case Attribute::StackProtect:
677     return bitc::ATTR_KIND_STACK_PROTECT;
678   case Attribute::StackProtectReq:
679     return bitc::ATTR_KIND_STACK_PROTECT_REQ;
680   case Attribute::StackProtectStrong:
681     return bitc::ATTR_KIND_STACK_PROTECT_STRONG;
682   case Attribute::SafeStack:
683     return bitc::ATTR_KIND_SAFESTACK;
684   case Attribute::StructRet:
685     return bitc::ATTR_KIND_STRUCT_RET;
686   case Attribute::SanitizeAddress:
687     return bitc::ATTR_KIND_SANITIZE_ADDRESS;
688   case Attribute::SanitizeThread:
689     return bitc::ATTR_KIND_SANITIZE_THREAD;
690   case Attribute::SanitizeMemory:
691     return bitc::ATTR_KIND_SANITIZE_MEMORY;
692   case Attribute::SwiftError:
693     return bitc::ATTR_KIND_SWIFT_ERROR;
694   case Attribute::SwiftSelf:
695     return bitc::ATTR_KIND_SWIFT_SELF;
696   case Attribute::UWTable:
697     return bitc::ATTR_KIND_UW_TABLE;
698   case Attribute::WriteOnly:
699     return bitc::ATTR_KIND_WRITEONLY;
700   case Attribute::ZExt:
701     return bitc::ATTR_KIND_Z_EXT;
702   case Attribute::EndAttrKinds:
703     llvm_unreachable("Can not encode end-attribute kinds marker.");
704   case Attribute::None:
705     llvm_unreachable("Can not encode none-attribute.");
706   }
707 
708   llvm_unreachable("Trying to encode unknown attribute");
709 }
710 
711 void ModuleBitcodeWriter::writeAttributeGroupTable() {
712   const std::vector<AttributeSet> &AttrGrps = VE.getAttributeGroups();
713   if (AttrGrps.empty()) return;
714 
715   Stream.EnterSubblock(bitc::PARAMATTR_GROUP_BLOCK_ID, 3);
716 
717   SmallVector<uint64_t, 64> Record;
718   for (unsigned i = 0, e = AttrGrps.size(); i != e; ++i) {
719     AttributeSet AS = AttrGrps[i];
720     for (unsigned i = 0, e = AS.getNumSlots(); i != e; ++i) {
721       AttributeSet A = AS.getSlotAttributes(i);
722 
723       Record.push_back(VE.getAttributeGroupID(A));
724       Record.push_back(AS.getSlotIndex(i));
725 
726       for (AttributeSet::iterator I = AS.begin(0), E = AS.end(0);
727            I != E; ++I) {
728         Attribute Attr = *I;
729         if (Attr.isEnumAttribute()) {
730           Record.push_back(0);
731           Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
732         } else if (Attr.isIntAttribute()) {
733           Record.push_back(1);
734           Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
735           Record.push_back(Attr.getValueAsInt());
736         } else {
737           StringRef Kind = Attr.getKindAsString();
738           StringRef Val = Attr.getValueAsString();
739 
740           Record.push_back(Val.empty() ? 3 : 4);
741           Record.append(Kind.begin(), Kind.end());
742           Record.push_back(0);
743           if (!Val.empty()) {
744             Record.append(Val.begin(), Val.end());
745             Record.push_back(0);
746           }
747         }
748       }
749 
750       Stream.EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
751       Record.clear();
752     }
753   }
754 
755   Stream.ExitBlock();
756 }
757 
758 void ModuleBitcodeWriter::writeAttributeTable() {
759   const std::vector<AttributeSet> &Attrs = VE.getAttributes();
760   if (Attrs.empty()) return;
761 
762   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
763 
764   SmallVector<uint64_t, 64> Record;
765   for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
766     const AttributeSet &A = Attrs[i];
767     for (unsigned i = 0, e = A.getNumSlots(); i != e; ++i)
768       Record.push_back(VE.getAttributeGroupID(A.getSlotAttributes(i)));
769 
770     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
771     Record.clear();
772   }
773 
774   Stream.ExitBlock();
775 }
776 
777 /// WriteTypeTable - Write out the type table for a module.
778 void ModuleBitcodeWriter::writeTypeTable() {
779   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
780 
781   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
782   SmallVector<uint64_t, 64> TypeVals;
783 
784   uint64_t NumBits = VE.computeBitsRequiredForTypeIndicies();
785 
786   // Abbrev for TYPE_CODE_POINTER.
787   auto Abbv = std::make_shared<BitCodeAbbrev>();
788   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
789   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
790   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
791   unsigned PtrAbbrev = Stream.EmitAbbrev(std::move(Abbv));
792 
793   // Abbrev for TYPE_CODE_FUNCTION.
794   Abbv = std::make_shared<BitCodeAbbrev>();
795   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
796   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
797   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
798   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
799 
800   unsigned FunctionAbbrev = Stream.EmitAbbrev(std::move(Abbv));
801 
802   // Abbrev for TYPE_CODE_STRUCT_ANON.
803   Abbv = std::make_shared<BitCodeAbbrev>();
804   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
805   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
806   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
807   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
808 
809   unsigned StructAnonAbbrev = Stream.EmitAbbrev(std::move(Abbv));
810 
811   // Abbrev for TYPE_CODE_STRUCT_NAME.
812   Abbv = std::make_shared<BitCodeAbbrev>();
813   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
814   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
815   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
816   unsigned StructNameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
817 
818   // Abbrev for TYPE_CODE_STRUCT_NAMED.
819   Abbv = std::make_shared<BitCodeAbbrev>();
820   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
821   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
822   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
823   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
824 
825   unsigned StructNamedAbbrev = Stream.EmitAbbrev(std::move(Abbv));
826 
827   // Abbrev for TYPE_CODE_ARRAY.
828   Abbv = std::make_shared<BitCodeAbbrev>();
829   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
830   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
831   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
832 
833   unsigned ArrayAbbrev = Stream.EmitAbbrev(std::move(Abbv));
834 
835   // Emit an entry count so the reader can reserve space.
836   TypeVals.push_back(TypeList.size());
837   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
838   TypeVals.clear();
839 
840   // Loop over all of the types, emitting each in turn.
841   for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
842     Type *T = TypeList[i];
843     int AbbrevToUse = 0;
844     unsigned Code = 0;
845 
846     switch (T->getTypeID()) {
847     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;      break;
848     case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;      break;
849     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;     break;
850     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE;    break;
851     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80;  break;
852     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128;     break;
853     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
854     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;     break;
855     case Type::MetadataTyID:  Code = bitc::TYPE_CODE_METADATA;  break;
856     case Type::X86_MMXTyID:   Code = bitc::TYPE_CODE_X86_MMX;   break;
857     case Type::TokenTyID:     Code = bitc::TYPE_CODE_TOKEN;     break;
858     case Type::IntegerTyID:
859       // INTEGER: [width]
860       Code = bitc::TYPE_CODE_INTEGER;
861       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
862       break;
863     case Type::PointerTyID: {
864       PointerType *PTy = cast<PointerType>(T);
865       // POINTER: [pointee type, address space]
866       Code = bitc::TYPE_CODE_POINTER;
867       TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
868       unsigned AddressSpace = PTy->getAddressSpace();
869       TypeVals.push_back(AddressSpace);
870       if (AddressSpace == 0) AbbrevToUse = PtrAbbrev;
871       break;
872     }
873     case Type::FunctionTyID: {
874       FunctionType *FT = cast<FunctionType>(T);
875       // FUNCTION: [isvararg, retty, paramty x N]
876       Code = bitc::TYPE_CODE_FUNCTION;
877       TypeVals.push_back(FT->isVarArg());
878       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
879       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
880         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
881       AbbrevToUse = FunctionAbbrev;
882       break;
883     }
884     case Type::StructTyID: {
885       StructType *ST = cast<StructType>(T);
886       // STRUCT: [ispacked, eltty x N]
887       TypeVals.push_back(ST->isPacked());
888       // Output all of the element types.
889       for (StructType::element_iterator I = ST->element_begin(),
890            E = ST->element_end(); I != E; ++I)
891         TypeVals.push_back(VE.getTypeID(*I));
892 
893       if (ST->isLiteral()) {
894         Code = bitc::TYPE_CODE_STRUCT_ANON;
895         AbbrevToUse = StructAnonAbbrev;
896       } else {
897         if (ST->isOpaque()) {
898           Code = bitc::TYPE_CODE_OPAQUE;
899         } else {
900           Code = bitc::TYPE_CODE_STRUCT_NAMED;
901           AbbrevToUse = StructNamedAbbrev;
902         }
903 
904         // Emit the name if it is present.
905         if (!ST->getName().empty())
906           writeStringRecord(Stream, bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
907                             StructNameAbbrev);
908       }
909       break;
910     }
911     case Type::ArrayTyID: {
912       ArrayType *AT = cast<ArrayType>(T);
913       // ARRAY: [numelts, eltty]
914       Code = bitc::TYPE_CODE_ARRAY;
915       TypeVals.push_back(AT->getNumElements());
916       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
917       AbbrevToUse = ArrayAbbrev;
918       break;
919     }
920     case Type::VectorTyID: {
921       VectorType *VT = cast<VectorType>(T);
922       // VECTOR [numelts, eltty]
923       Code = bitc::TYPE_CODE_VECTOR;
924       TypeVals.push_back(VT->getNumElements());
925       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
926       break;
927     }
928     }
929 
930     // Emit the finished record.
931     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
932     TypeVals.clear();
933   }
934 
935   Stream.ExitBlock();
936 }
937 
938 static unsigned getEncodedLinkage(const GlobalValue::LinkageTypes Linkage) {
939   switch (Linkage) {
940   case GlobalValue::ExternalLinkage:
941     return 0;
942   case GlobalValue::WeakAnyLinkage:
943     return 16;
944   case GlobalValue::AppendingLinkage:
945     return 2;
946   case GlobalValue::InternalLinkage:
947     return 3;
948   case GlobalValue::LinkOnceAnyLinkage:
949     return 18;
950   case GlobalValue::ExternalWeakLinkage:
951     return 7;
952   case GlobalValue::CommonLinkage:
953     return 8;
954   case GlobalValue::PrivateLinkage:
955     return 9;
956   case GlobalValue::WeakODRLinkage:
957     return 17;
958   case GlobalValue::LinkOnceODRLinkage:
959     return 19;
960   case GlobalValue::AvailableExternallyLinkage:
961     return 12;
962   }
963   llvm_unreachable("Invalid linkage");
964 }
965 
966 static unsigned getEncodedLinkage(const GlobalValue &GV) {
967   return getEncodedLinkage(GV.getLinkage());
968 }
969 
970 // Decode the flags for GlobalValue in the summary
971 static uint64_t getEncodedGVSummaryFlags(GlobalValueSummary::GVFlags Flags) {
972   uint64_t RawFlags = 0;
973 
974   RawFlags |= Flags.NotEligibleToImport; // bool
975   // Linkage don't need to be remapped at that time for the summary. Any future
976   // change to the getEncodedLinkage() function will need to be taken into
977   // account here as well.
978   RawFlags = (RawFlags << 4) | Flags.Linkage; // 4 bits
979 
980   return RawFlags;
981 }
982 
983 static unsigned getEncodedVisibility(const GlobalValue &GV) {
984   switch (GV.getVisibility()) {
985   case GlobalValue::DefaultVisibility:   return 0;
986   case GlobalValue::HiddenVisibility:    return 1;
987   case GlobalValue::ProtectedVisibility: return 2;
988   }
989   llvm_unreachable("Invalid visibility");
990 }
991 
992 static unsigned getEncodedDLLStorageClass(const GlobalValue &GV) {
993   switch (GV.getDLLStorageClass()) {
994   case GlobalValue::DefaultStorageClass:   return 0;
995   case GlobalValue::DLLImportStorageClass: return 1;
996   case GlobalValue::DLLExportStorageClass: return 2;
997   }
998   llvm_unreachable("Invalid DLL storage class");
999 }
1000 
1001 static unsigned getEncodedThreadLocalMode(const GlobalValue &GV) {
1002   switch (GV.getThreadLocalMode()) {
1003     case GlobalVariable::NotThreadLocal:         return 0;
1004     case GlobalVariable::GeneralDynamicTLSModel: return 1;
1005     case GlobalVariable::LocalDynamicTLSModel:   return 2;
1006     case GlobalVariable::InitialExecTLSModel:    return 3;
1007     case GlobalVariable::LocalExecTLSModel:      return 4;
1008   }
1009   llvm_unreachable("Invalid TLS model");
1010 }
1011 
1012 static unsigned getEncodedComdatSelectionKind(const Comdat &C) {
1013   switch (C.getSelectionKind()) {
1014   case Comdat::Any:
1015     return bitc::COMDAT_SELECTION_KIND_ANY;
1016   case Comdat::ExactMatch:
1017     return bitc::COMDAT_SELECTION_KIND_EXACT_MATCH;
1018   case Comdat::Largest:
1019     return bitc::COMDAT_SELECTION_KIND_LARGEST;
1020   case Comdat::NoDuplicates:
1021     return bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES;
1022   case Comdat::SameSize:
1023     return bitc::COMDAT_SELECTION_KIND_SAME_SIZE;
1024   }
1025   llvm_unreachable("Invalid selection kind");
1026 }
1027 
1028 static unsigned getEncodedUnnamedAddr(const GlobalValue &GV) {
1029   switch (GV.getUnnamedAddr()) {
1030   case GlobalValue::UnnamedAddr::None:   return 0;
1031   case GlobalValue::UnnamedAddr::Local:  return 2;
1032   case GlobalValue::UnnamedAddr::Global: return 1;
1033   }
1034   llvm_unreachable("Invalid unnamed_addr");
1035 }
1036 
1037 void ModuleBitcodeWriter::writeComdats() {
1038   SmallVector<unsigned, 64> Vals;
1039   for (const Comdat *C : VE.getComdats()) {
1040     // COMDAT: [selection_kind, name]
1041     Vals.push_back(getEncodedComdatSelectionKind(*C));
1042     size_t Size = C->getName().size();
1043     assert(isUInt<32>(Size));
1044     Vals.push_back(Size);
1045     for (char Chr : C->getName())
1046       Vals.push_back((unsigned char)Chr);
1047     Stream.EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
1048     Vals.clear();
1049   }
1050 }
1051 
1052 /// Write a record that will eventually hold the word offset of the
1053 /// module-level VST. For now the offset is 0, which will be backpatched
1054 /// after the real VST is written. Saves the bit offset to backpatch.
1055 void BitcodeWriterBase::writeValueSymbolTableForwardDecl() {
1056   // Write a placeholder value in for the offset of the real VST,
1057   // which is written after the function blocks so that it can include
1058   // the offset of each function. The placeholder offset will be
1059   // updated when the real VST is written.
1060   auto Abbv = std::make_shared<BitCodeAbbrev>();
1061   Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_VSTOFFSET));
1062   // Blocks are 32-bit aligned, so we can use a 32-bit word offset to
1063   // hold the real VST offset. Must use fixed instead of VBR as we don't
1064   // know how many VBR chunks to reserve ahead of time.
1065   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
1066   unsigned VSTOffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1067 
1068   // Emit the placeholder
1069   uint64_t Vals[] = {bitc::MODULE_CODE_VSTOFFSET, 0};
1070   Stream.EmitRecordWithAbbrev(VSTOffsetAbbrev, Vals);
1071 
1072   // Compute and save the bit offset to the placeholder, which will be
1073   // patched when the real VST is written. We can simply subtract the 32-bit
1074   // fixed size from the current bit number to get the location to backpatch.
1075   VSTOffsetPlaceholder = Stream.GetCurrentBitNo() - 32;
1076 }
1077 
1078 enum StringEncoding { SE_Char6, SE_Fixed7, SE_Fixed8 };
1079 
1080 /// Determine the encoding to use for the given string name and length.
1081 static StringEncoding getStringEncoding(const char *Str, unsigned StrLen) {
1082   bool isChar6 = true;
1083   for (const char *C = Str, *E = C + StrLen; C != E; ++C) {
1084     if (isChar6)
1085       isChar6 = BitCodeAbbrevOp::isChar6(*C);
1086     if ((unsigned char)*C & 128)
1087       // don't bother scanning the rest.
1088       return SE_Fixed8;
1089   }
1090   if (isChar6)
1091     return SE_Char6;
1092   else
1093     return SE_Fixed7;
1094 }
1095 
1096 /// Emit top-level description of module, including target triple, inline asm,
1097 /// descriptors for global variables, and function prototype info.
1098 /// Returns the bit offset to backpatch with the location of the real VST.
1099 void ModuleBitcodeWriter::writeModuleInfo() {
1100   // Emit various pieces of data attached to a module.
1101   if (!M.getTargetTriple().empty())
1102     writeStringRecord(Stream, bitc::MODULE_CODE_TRIPLE, M.getTargetTriple(),
1103                       0 /*TODO*/);
1104   const std::string &DL = M.getDataLayoutStr();
1105   if (!DL.empty())
1106     writeStringRecord(Stream, bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/);
1107   if (!M.getModuleInlineAsm().empty())
1108     writeStringRecord(Stream, bitc::MODULE_CODE_ASM, M.getModuleInlineAsm(),
1109                       0 /*TODO*/);
1110 
1111   // Emit information about sections and GC, computing how many there are. Also
1112   // compute the maximum alignment value.
1113   std::map<std::string, unsigned> SectionMap;
1114   std::map<std::string, unsigned> GCMap;
1115   unsigned MaxAlignment = 0;
1116   unsigned MaxGlobalType = 0;
1117   for (const GlobalValue &GV : M.globals()) {
1118     MaxAlignment = std::max(MaxAlignment, GV.getAlignment());
1119     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getValueType()));
1120     if (GV.hasSection()) {
1121       // Give section names unique ID's.
1122       unsigned &Entry = SectionMap[GV.getSection()];
1123       if (!Entry) {
1124         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
1125                           0 /*TODO*/);
1126         Entry = SectionMap.size();
1127       }
1128     }
1129   }
1130   for (const Function &F : M) {
1131     MaxAlignment = std::max(MaxAlignment, F.getAlignment());
1132     if (F.hasSection()) {
1133       // Give section names unique ID's.
1134       unsigned &Entry = SectionMap[F.getSection()];
1135       if (!Entry) {
1136         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
1137                           0 /*TODO*/);
1138         Entry = SectionMap.size();
1139       }
1140     }
1141     if (F.hasGC()) {
1142       // Same for GC names.
1143       unsigned &Entry = GCMap[F.getGC()];
1144       if (!Entry) {
1145         writeStringRecord(Stream, bitc::MODULE_CODE_GCNAME, F.getGC(),
1146                           0 /*TODO*/);
1147         Entry = GCMap.size();
1148       }
1149     }
1150   }
1151 
1152   // Emit abbrev for globals, now that we know # sections and max alignment.
1153   unsigned SimpleGVarAbbrev = 0;
1154   if (!M.global_empty()) {
1155     // Add an abbrev for common globals with no visibility or thread localness.
1156     auto Abbv = std::make_shared<BitCodeAbbrev>();
1157     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
1158     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1159                               Log2_32_Ceil(MaxGlobalType+1)));
1160     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddrSpace << 2
1161                                                            //| explicitType << 1
1162                                                            //| constant
1163     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Initializer.
1164     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // Linkage.
1165     if (MaxAlignment == 0)                                 // Alignment.
1166       Abbv->Add(BitCodeAbbrevOp(0));
1167     else {
1168       unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
1169       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1170                                Log2_32_Ceil(MaxEncAlignment+1)));
1171     }
1172     if (SectionMap.empty())                                    // Section.
1173       Abbv->Add(BitCodeAbbrevOp(0));
1174     else
1175       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1176                                Log2_32_Ceil(SectionMap.size()+1)));
1177     // Don't bother emitting vis + thread local.
1178     SimpleGVarAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1179   }
1180 
1181   // Emit the global variable information.
1182   SmallVector<unsigned, 64> Vals;
1183   for (const GlobalVariable &GV : M.globals()) {
1184     unsigned AbbrevToUse = 0;
1185 
1186     // GLOBALVAR: [type, isconst, initid,
1187     //             linkage, alignment, section, visibility, threadlocal,
1188     //             unnamed_addr, externally_initialized, dllstorageclass,
1189     //             comdat]
1190     Vals.push_back(VE.getTypeID(GV.getValueType()));
1191     Vals.push_back(GV.getType()->getAddressSpace() << 2 | 2 | GV.isConstant());
1192     Vals.push_back(GV.isDeclaration() ? 0 :
1193                    (VE.getValueID(GV.getInitializer()) + 1));
1194     Vals.push_back(getEncodedLinkage(GV));
1195     Vals.push_back(Log2_32(GV.getAlignment())+1);
1196     Vals.push_back(GV.hasSection() ? SectionMap[GV.getSection()] : 0);
1197     if (GV.isThreadLocal() ||
1198         GV.getVisibility() != GlobalValue::DefaultVisibility ||
1199         GV.getUnnamedAddr() != GlobalValue::UnnamedAddr::None ||
1200         GV.isExternallyInitialized() ||
1201         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
1202         GV.hasComdat()) {
1203       Vals.push_back(getEncodedVisibility(GV));
1204       Vals.push_back(getEncodedThreadLocalMode(GV));
1205       Vals.push_back(getEncodedUnnamedAddr(GV));
1206       Vals.push_back(GV.isExternallyInitialized());
1207       Vals.push_back(getEncodedDLLStorageClass(GV));
1208       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
1209     } else {
1210       AbbrevToUse = SimpleGVarAbbrev;
1211     }
1212 
1213     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
1214     Vals.clear();
1215   }
1216 
1217   // Emit the function proto information.
1218   for (const Function &F : M) {
1219     // FUNCTION:  [type, callingconv, isproto, linkage, paramattrs, alignment,
1220     //             section, visibility, gc, unnamed_addr, prologuedata,
1221     //             dllstorageclass, comdat, prefixdata, personalityfn]
1222     Vals.push_back(VE.getTypeID(F.getFunctionType()));
1223     Vals.push_back(F.getCallingConv());
1224     Vals.push_back(F.isDeclaration());
1225     Vals.push_back(getEncodedLinkage(F));
1226     Vals.push_back(VE.getAttributeID(F.getAttributes()));
1227     Vals.push_back(Log2_32(F.getAlignment())+1);
1228     Vals.push_back(F.hasSection() ? SectionMap[F.getSection()] : 0);
1229     Vals.push_back(getEncodedVisibility(F));
1230     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
1231     Vals.push_back(getEncodedUnnamedAddr(F));
1232     Vals.push_back(F.hasPrologueData() ? (VE.getValueID(F.getPrologueData()) + 1)
1233                                        : 0);
1234     Vals.push_back(getEncodedDLLStorageClass(F));
1235     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
1236     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
1237                                      : 0);
1238     Vals.push_back(
1239         F.hasPersonalityFn() ? (VE.getValueID(F.getPersonalityFn()) + 1) : 0);
1240 
1241     unsigned AbbrevToUse = 0;
1242     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
1243     Vals.clear();
1244   }
1245 
1246   // Emit the alias information.
1247   for (const GlobalAlias &A : M.aliases()) {
1248     // ALIAS: [alias type, aliasee val#, linkage, visibility, dllstorageclass,
1249     //         threadlocal, unnamed_addr]
1250     Vals.push_back(VE.getTypeID(A.getValueType()));
1251     Vals.push_back(A.getType()->getAddressSpace());
1252     Vals.push_back(VE.getValueID(A.getAliasee()));
1253     Vals.push_back(getEncodedLinkage(A));
1254     Vals.push_back(getEncodedVisibility(A));
1255     Vals.push_back(getEncodedDLLStorageClass(A));
1256     Vals.push_back(getEncodedThreadLocalMode(A));
1257     Vals.push_back(getEncodedUnnamedAddr(A));
1258     unsigned AbbrevToUse = 0;
1259     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
1260     Vals.clear();
1261   }
1262 
1263   // Emit the ifunc information.
1264   for (const GlobalIFunc &I : M.ifuncs()) {
1265     // IFUNC: [ifunc type, address space, resolver val#, linkage, visibility]
1266     Vals.push_back(VE.getTypeID(I.getValueType()));
1267     Vals.push_back(I.getType()->getAddressSpace());
1268     Vals.push_back(VE.getValueID(I.getResolver()));
1269     Vals.push_back(getEncodedLinkage(I));
1270     Vals.push_back(getEncodedVisibility(I));
1271     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
1272     Vals.clear();
1273   }
1274 
1275   // Emit the module's source file name.
1276   {
1277     StringEncoding Bits = getStringEncoding(M.getSourceFileName().data(),
1278                                             M.getSourceFileName().size());
1279     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
1280     if (Bits == SE_Char6)
1281       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
1282     else if (Bits == SE_Fixed7)
1283       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
1284 
1285     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
1286     auto Abbv = std::make_shared<BitCodeAbbrev>();
1287     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
1288     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1289     Abbv->Add(AbbrevOpToUse);
1290     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1291 
1292     for (const auto P : M.getSourceFileName())
1293       Vals.push_back((unsigned char)P);
1294 
1295     // Emit the finished record.
1296     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
1297     Vals.clear();
1298   }
1299 
1300   // If we have a VST, write the VSTOFFSET record placeholder.
1301   if (M.getValueSymbolTable().empty())
1302     return;
1303   writeValueSymbolTableForwardDecl();
1304 }
1305 
1306 static uint64_t getOptimizationFlags(const Value *V) {
1307   uint64_t Flags = 0;
1308 
1309   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
1310     if (OBO->hasNoSignedWrap())
1311       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
1312     if (OBO->hasNoUnsignedWrap())
1313       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
1314   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
1315     if (PEO->isExact())
1316       Flags |= 1 << bitc::PEO_EXACT;
1317   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
1318     if (FPMO->hasUnsafeAlgebra())
1319       Flags |= FastMathFlags::UnsafeAlgebra;
1320     if (FPMO->hasNoNaNs())
1321       Flags |= FastMathFlags::NoNaNs;
1322     if (FPMO->hasNoInfs())
1323       Flags |= FastMathFlags::NoInfs;
1324     if (FPMO->hasNoSignedZeros())
1325       Flags |= FastMathFlags::NoSignedZeros;
1326     if (FPMO->hasAllowReciprocal())
1327       Flags |= FastMathFlags::AllowReciprocal;
1328   }
1329 
1330   return Flags;
1331 }
1332 
1333 void ModuleBitcodeWriter::writeValueAsMetadata(
1334     const ValueAsMetadata *MD, SmallVectorImpl<uint64_t> &Record) {
1335   // Mimic an MDNode with a value as one operand.
1336   Value *V = MD->getValue();
1337   Record.push_back(VE.getTypeID(V->getType()));
1338   Record.push_back(VE.getValueID(V));
1339   Stream.EmitRecord(bitc::METADATA_VALUE, Record, 0);
1340   Record.clear();
1341 }
1342 
1343 void ModuleBitcodeWriter::writeMDTuple(const MDTuple *N,
1344                                        SmallVectorImpl<uint64_t> &Record,
1345                                        unsigned Abbrev) {
1346   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
1347     Metadata *MD = N->getOperand(i);
1348     assert(!(MD && isa<LocalAsMetadata>(MD)) &&
1349            "Unexpected function-local metadata");
1350     Record.push_back(VE.getMetadataOrNullID(MD));
1351   }
1352   Stream.EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
1353                                     : bitc::METADATA_NODE,
1354                     Record, Abbrev);
1355   Record.clear();
1356 }
1357 
1358 unsigned ModuleBitcodeWriter::createDILocationAbbrev() {
1359   // Assume the column is usually under 128, and always output the inlined-at
1360   // location (it's never more expensive than building an array size 1).
1361   auto Abbv = std::make_shared<BitCodeAbbrev>();
1362   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
1363   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1364   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1365   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1366   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1367   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1368   return Stream.EmitAbbrev(std::move(Abbv));
1369 }
1370 
1371 void ModuleBitcodeWriter::writeDILocation(const DILocation *N,
1372                                           SmallVectorImpl<uint64_t> &Record,
1373                                           unsigned &Abbrev) {
1374   if (!Abbrev)
1375     Abbrev = createDILocationAbbrev();
1376 
1377   Record.push_back(N->isDistinct());
1378   Record.push_back(N->getLine());
1379   Record.push_back(N->getColumn());
1380   Record.push_back(VE.getMetadataID(N->getScope()));
1381   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
1382 
1383   Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
1384   Record.clear();
1385 }
1386 
1387 unsigned ModuleBitcodeWriter::createGenericDINodeAbbrev() {
1388   // Assume the column is usually under 128, and always output the inlined-at
1389   // location (it's never more expensive than building an array size 1).
1390   auto Abbv = std::make_shared<BitCodeAbbrev>();
1391   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
1392   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1393   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1394   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1395   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1396   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1397   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1398   return Stream.EmitAbbrev(std::move(Abbv));
1399 }
1400 
1401 void ModuleBitcodeWriter::writeGenericDINode(const GenericDINode *N,
1402                                              SmallVectorImpl<uint64_t> &Record,
1403                                              unsigned &Abbrev) {
1404   if (!Abbrev)
1405     Abbrev = createGenericDINodeAbbrev();
1406 
1407   Record.push_back(N->isDistinct());
1408   Record.push_back(N->getTag());
1409   Record.push_back(0); // Per-tag version field; unused for now.
1410 
1411   for (auto &I : N->operands())
1412     Record.push_back(VE.getMetadataOrNullID(I));
1413 
1414   Stream.EmitRecord(bitc::METADATA_GENERIC_DEBUG, Record, Abbrev);
1415   Record.clear();
1416 }
1417 
1418 static uint64_t rotateSign(int64_t I) {
1419   uint64_t U = I;
1420   return I < 0 ? ~(U << 1) : U << 1;
1421 }
1422 
1423 void ModuleBitcodeWriter::writeDISubrange(const DISubrange *N,
1424                                           SmallVectorImpl<uint64_t> &Record,
1425                                           unsigned Abbrev) {
1426   Record.push_back(N->isDistinct());
1427   Record.push_back(N->getCount());
1428   Record.push_back(rotateSign(N->getLowerBound()));
1429 
1430   Stream.EmitRecord(bitc::METADATA_SUBRANGE, Record, Abbrev);
1431   Record.clear();
1432 }
1433 
1434 void ModuleBitcodeWriter::writeDIEnumerator(const DIEnumerator *N,
1435                                             SmallVectorImpl<uint64_t> &Record,
1436                                             unsigned Abbrev) {
1437   Record.push_back(N->isDistinct());
1438   Record.push_back(rotateSign(N->getValue()));
1439   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1440 
1441   Stream.EmitRecord(bitc::METADATA_ENUMERATOR, Record, Abbrev);
1442   Record.clear();
1443 }
1444 
1445 void ModuleBitcodeWriter::writeDIBasicType(const DIBasicType *N,
1446                                            SmallVectorImpl<uint64_t> &Record,
1447                                            unsigned Abbrev) {
1448   Record.push_back(N->isDistinct());
1449   Record.push_back(N->getTag());
1450   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1451   Record.push_back(N->getSizeInBits());
1452   Record.push_back(N->getAlignInBits());
1453   Record.push_back(N->getEncoding());
1454 
1455   Stream.EmitRecord(bitc::METADATA_BASIC_TYPE, Record, Abbrev);
1456   Record.clear();
1457 }
1458 
1459 void ModuleBitcodeWriter::writeDIDerivedType(const DIDerivedType *N,
1460                                              SmallVectorImpl<uint64_t> &Record,
1461                                              unsigned Abbrev) {
1462   Record.push_back(N->isDistinct());
1463   Record.push_back(N->getTag());
1464   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1465   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1466   Record.push_back(N->getLine());
1467   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1468   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1469   Record.push_back(N->getSizeInBits());
1470   Record.push_back(N->getAlignInBits());
1471   Record.push_back(N->getOffsetInBits());
1472   Record.push_back(N->getFlags());
1473   Record.push_back(VE.getMetadataOrNullID(N->getExtraData()));
1474 
1475   Stream.EmitRecord(bitc::METADATA_DERIVED_TYPE, Record, Abbrev);
1476   Record.clear();
1477 }
1478 
1479 void ModuleBitcodeWriter::writeDICompositeType(
1480     const DICompositeType *N, SmallVectorImpl<uint64_t> &Record,
1481     unsigned Abbrev) {
1482   const unsigned IsNotUsedInOldTypeRef = 0x2;
1483   Record.push_back(IsNotUsedInOldTypeRef | (unsigned)N->isDistinct());
1484   Record.push_back(N->getTag());
1485   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1486   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1487   Record.push_back(N->getLine());
1488   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1489   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1490   Record.push_back(N->getSizeInBits());
1491   Record.push_back(N->getAlignInBits());
1492   Record.push_back(N->getOffsetInBits());
1493   Record.push_back(N->getFlags());
1494   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1495   Record.push_back(N->getRuntimeLang());
1496   Record.push_back(VE.getMetadataOrNullID(N->getVTableHolder()));
1497   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1498   Record.push_back(VE.getMetadataOrNullID(N->getRawIdentifier()));
1499 
1500   Stream.EmitRecord(bitc::METADATA_COMPOSITE_TYPE, Record, Abbrev);
1501   Record.clear();
1502 }
1503 
1504 void ModuleBitcodeWriter::writeDISubroutineType(
1505     const DISubroutineType *N, SmallVectorImpl<uint64_t> &Record,
1506     unsigned Abbrev) {
1507   const unsigned HasNoOldTypeRefs = 0x2;
1508   Record.push_back(HasNoOldTypeRefs | (unsigned)N->isDistinct());
1509   Record.push_back(N->getFlags());
1510   Record.push_back(VE.getMetadataOrNullID(N->getTypeArray().get()));
1511   Record.push_back(N->getCC());
1512 
1513   Stream.EmitRecord(bitc::METADATA_SUBROUTINE_TYPE, Record, Abbrev);
1514   Record.clear();
1515 }
1516 
1517 void ModuleBitcodeWriter::writeDIFile(const DIFile *N,
1518                                       SmallVectorImpl<uint64_t> &Record,
1519                                       unsigned Abbrev) {
1520   Record.push_back(N->isDistinct());
1521   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
1522   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
1523   Record.push_back(N->getChecksumKind());
1524   Record.push_back(VE.getMetadataOrNullID(N->getRawChecksum()));
1525 
1526   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
1527   Record.clear();
1528 }
1529 
1530 void ModuleBitcodeWriter::writeDICompileUnit(const DICompileUnit *N,
1531                                              SmallVectorImpl<uint64_t> &Record,
1532                                              unsigned Abbrev) {
1533   assert(N->isDistinct() && "Expected distinct compile units");
1534   Record.push_back(/* IsDistinct */ true);
1535   Record.push_back(N->getSourceLanguage());
1536   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1537   Record.push_back(VE.getMetadataOrNullID(N->getRawProducer()));
1538   Record.push_back(N->isOptimized());
1539   Record.push_back(VE.getMetadataOrNullID(N->getRawFlags()));
1540   Record.push_back(N->getRuntimeVersion());
1541   Record.push_back(VE.getMetadataOrNullID(N->getRawSplitDebugFilename()));
1542   Record.push_back(N->getEmissionKind());
1543   Record.push_back(VE.getMetadataOrNullID(N->getEnumTypes().get()));
1544   Record.push_back(VE.getMetadataOrNullID(N->getRetainedTypes().get()));
1545   Record.push_back(/* subprograms */ 0);
1546   Record.push_back(VE.getMetadataOrNullID(N->getGlobalVariables().get()));
1547   Record.push_back(VE.getMetadataOrNullID(N->getImportedEntities().get()));
1548   Record.push_back(N->getDWOId());
1549   Record.push_back(VE.getMetadataOrNullID(N->getMacros().get()));
1550   Record.push_back(N->getSplitDebugInlining());
1551 
1552   Stream.EmitRecord(bitc::METADATA_COMPILE_UNIT, Record, Abbrev);
1553   Record.clear();
1554 }
1555 
1556 void ModuleBitcodeWriter::writeDISubprogram(const DISubprogram *N,
1557                                             SmallVectorImpl<uint64_t> &Record,
1558                                             unsigned Abbrev) {
1559   uint64_t HasUnitFlag = 1 << 1;
1560   Record.push_back(N->isDistinct() | HasUnitFlag);
1561   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1562   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1563   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1564   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1565   Record.push_back(N->getLine());
1566   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1567   Record.push_back(N->isLocalToUnit());
1568   Record.push_back(N->isDefinition());
1569   Record.push_back(N->getScopeLine());
1570   Record.push_back(VE.getMetadataOrNullID(N->getContainingType()));
1571   Record.push_back(N->getVirtuality());
1572   Record.push_back(N->getVirtualIndex());
1573   Record.push_back(N->getFlags());
1574   Record.push_back(N->isOptimized());
1575   Record.push_back(VE.getMetadataOrNullID(N->getRawUnit()));
1576   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1577   Record.push_back(VE.getMetadataOrNullID(N->getDeclaration()));
1578   Record.push_back(VE.getMetadataOrNullID(N->getVariables().get()));
1579   Record.push_back(N->getThisAdjustment());
1580 
1581   Stream.EmitRecord(bitc::METADATA_SUBPROGRAM, Record, Abbrev);
1582   Record.clear();
1583 }
1584 
1585 void ModuleBitcodeWriter::writeDILexicalBlock(const DILexicalBlock *N,
1586                                               SmallVectorImpl<uint64_t> &Record,
1587                                               unsigned Abbrev) {
1588   Record.push_back(N->isDistinct());
1589   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1590   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1591   Record.push_back(N->getLine());
1592   Record.push_back(N->getColumn());
1593 
1594   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK, Record, Abbrev);
1595   Record.clear();
1596 }
1597 
1598 void ModuleBitcodeWriter::writeDILexicalBlockFile(
1599     const DILexicalBlockFile *N, SmallVectorImpl<uint64_t> &Record,
1600     unsigned Abbrev) {
1601   Record.push_back(N->isDistinct());
1602   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1603   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1604   Record.push_back(N->getDiscriminator());
1605 
1606   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK_FILE, Record, Abbrev);
1607   Record.clear();
1608 }
1609 
1610 void ModuleBitcodeWriter::writeDINamespace(const DINamespace *N,
1611                                            SmallVectorImpl<uint64_t> &Record,
1612                                            unsigned Abbrev) {
1613   Record.push_back(N->isDistinct() | N->getExportSymbols() << 1);
1614   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1615   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1616   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1617   Record.push_back(N->getLine());
1618 
1619   Stream.EmitRecord(bitc::METADATA_NAMESPACE, Record, Abbrev);
1620   Record.clear();
1621 }
1622 
1623 void ModuleBitcodeWriter::writeDIMacro(const DIMacro *N,
1624                                        SmallVectorImpl<uint64_t> &Record,
1625                                        unsigned Abbrev) {
1626   Record.push_back(N->isDistinct());
1627   Record.push_back(N->getMacinfoType());
1628   Record.push_back(N->getLine());
1629   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1630   Record.push_back(VE.getMetadataOrNullID(N->getRawValue()));
1631 
1632   Stream.EmitRecord(bitc::METADATA_MACRO, Record, Abbrev);
1633   Record.clear();
1634 }
1635 
1636 void ModuleBitcodeWriter::writeDIMacroFile(const DIMacroFile *N,
1637                                            SmallVectorImpl<uint64_t> &Record,
1638                                            unsigned Abbrev) {
1639   Record.push_back(N->isDistinct());
1640   Record.push_back(N->getMacinfoType());
1641   Record.push_back(N->getLine());
1642   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1643   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1644 
1645   Stream.EmitRecord(bitc::METADATA_MACRO_FILE, Record, Abbrev);
1646   Record.clear();
1647 }
1648 
1649 void ModuleBitcodeWriter::writeDIModule(const DIModule *N,
1650                                         SmallVectorImpl<uint64_t> &Record,
1651                                         unsigned Abbrev) {
1652   Record.push_back(N->isDistinct());
1653   for (auto &I : N->operands())
1654     Record.push_back(VE.getMetadataOrNullID(I));
1655 
1656   Stream.EmitRecord(bitc::METADATA_MODULE, Record, Abbrev);
1657   Record.clear();
1658 }
1659 
1660 void ModuleBitcodeWriter::writeDITemplateTypeParameter(
1661     const DITemplateTypeParameter *N, SmallVectorImpl<uint64_t> &Record,
1662     unsigned Abbrev) {
1663   Record.push_back(N->isDistinct());
1664   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1665   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1666 
1667   Stream.EmitRecord(bitc::METADATA_TEMPLATE_TYPE, Record, Abbrev);
1668   Record.clear();
1669 }
1670 
1671 void ModuleBitcodeWriter::writeDITemplateValueParameter(
1672     const DITemplateValueParameter *N, SmallVectorImpl<uint64_t> &Record,
1673     unsigned Abbrev) {
1674   Record.push_back(N->isDistinct());
1675   Record.push_back(N->getTag());
1676   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1677   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1678   Record.push_back(VE.getMetadataOrNullID(N->getValue()));
1679 
1680   Stream.EmitRecord(bitc::METADATA_TEMPLATE_VALUE, Record, Abbrev);
1681   Record.clear();
1682 }
1683 
1684 void ModuleBitcodeWriter::writeDIGlobalVariable(
1685     const DIGlobalVariable *N, SmallVectorImpl<uint64_t> &Record,
1686     unsigned Abbrev) {
1687   const uint64_t Version = 1 << 1;
1688   Record.push_back((uint64_t)N->isDistinct() | Version);
1689   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1690   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1691   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1692   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1693   Record.push_back(N->getLine());
1694   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1695   Record.push_back(N->isLocalToUnit());
1696   Record.push_back(N->isDefinition());
1697   Record.push_back(/* expr */ 0);
1698   Record.push_back(VE.getMetadataOrNullID(N->getStaticDataMemberDeclaration()));
1699   Record.push_back(N->getAlignInBits());
1700 
1701   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR, Record, Abbrev);
1702   Record.clear();
1703 }
1704 
1705 void ModuleBitcodeWriter::writeDILocalVariable(
1706     const DILocalVariable *N, SmallVectorImpl<uint64_t> &Record,
1707     unsigned Abbrev) {
1708   // In order to support all possible bitcode formats in BitcodeReader we need
1709   // to distinguish the following cases:
1710   // 1) Record has no artificial tag (Record[1]),
1711   //   has no obsolete inlinedAt field (Record[9]).
1712   //   In this case Record size will be 8, HasAlignment flag is false.
1713   // 2) Record has artificial tag (Record[1]),
1714   //   has no obsolete inlignedAt field (Record[9]).
1715   //   In this case Record size will be 9, HasAlignment flag is false.
1716   // 3) Record has both artificial tag (Record[1]) and
1717   //   obsolete inlignedAt field (Record[9]).
1718   //   In this case Record size will be 10, HasAlignment flag is false.
1719   // 4) Record has neither artificial tag, nor inlignedAt field, but
1720   //   HasAlignment flag is true and Record[8] contains alignment value.
1721   const uint64_t HasAlignmentFlag = 1 << 1;
1722   Record.push_back((uint64_t)N->isDistinct() | HasAlignmentFlag);
1723   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1724   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1725   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1726   Record.push_back(N->getLine());
1727   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1728   Record.push_back(N->getArg());
1729   Record.push_back(N->getFlags());
1730   Record.push_back(N->getAlignInBits());
1731 
1732   Stream.EmitRecord(bitc::METADATA_LOCAL_VAR, Record, Abbrev);
1733   Record.clear();
1734 }
1735 
1736 void ModuleBitcodeWriter::writeDIExpression(const DIExpression *N,
1737                                             SmallVectorImpl<uint64_t> &Record,
1738                                             unsigned Abbrev) {
1739   Record.reserve(N->getElements().size() + 1);
1740 
1741   const uint64_t HasOpFragmentFlag = 1 << 1;
1742   Record.push_back((uint64_t)N->isDistinct() | HasOpFragmentFlag);
1743   Record.append(N->elements_begin(), N->elements_end());
1744 
1745   Stream.EmitRecord(bitc::METADATA_EXPRESSION, Record, Abbrev);
1746   Record.clear();
1747 }
1748 
1749 void ModuleBitcodeWriter::writeDIGlobalVariableExpression(
1750     const DIGlobalVariableExpression *N, SmallVectorImpl<uint64_t> &Record,
1751     unsigned Abbrev) {
1752   Record.push_back(N->isDistinct());
1753   Record.push_back(VE.getMetadataOrNullID(N->getVariable()));
1754   Record.push_back(VE.getMetadataOrNullID(N->getExpression()));
1755 
1756   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR_EXPR, Record, Abbrev);
1757   Record.clear();
1758 }
1759 
1760 void ModuleBitcodeWriter::writeDIObjCProperty(const DIObjCProperty *N,
1761                                               SmallVectorImpl<uint64_t> &Record,
1762                                               unsigned Abbrev) {
1763   Record.push_back(N->isDistinct());
1764   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1765   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1766   Record.push_back(N->getLine());
1767   Record.push_back(VE.getMetadataOrNullID(N->getRawSetterName()));
1768   Record.push_back(VE.getMetadataOrNullID(N->getRawGetterName()));
1769   Record.push_back(N->getAttributes());
1770   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1771 
1772   Stream.EmitRecord(bitc::METADATA_OBJC_PROPERTY, Record, Abbrev);
1773   Record.clear();
1774 }
1775 
1776 void ModuleBitcodeWriter::writeDIImportedEntity(
1777     const DIImportedEntity *N, SmallVectorImpl<uint64_t> &Record,
1778     unsigned Abbrev) {
1779   Record.push_back(N->isDistinct());
1780   Record.push_back(N->getTag());
1781   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1782   Record.push_back(VE.getMetadataOrNullID(N->getEntity()));
1783   Record.push_back(N->getLine());
1784   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1785 
1786   Stream.EmitRecord(bitc::METADATA_IMPORTED_ENTITY, Record, Abbrev);
1787   Record.clear();
1788 }
1789 
1790 unsigned ModuleBitcodeWriter::createNamedMetadataAbbrev() {
1791   auto Abbv = std::make_shared<BitCodeAbbrev>();
1792   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
1793   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1794   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1795   return Stream.EmitAbbrev(std::move(Abbv));
1796 }
1797 
1798 void ModuleBitcodeWriter::writeNamedMetadata(
1799     SmallVectorImpl<uint64_t> &Record) {
1800   if (M.named_metadata_empty())
1801     return;
1802 
1803   unsigned Abbrev = createNamedMetadataAbbrev();
1804   for (const NamedMDNode &NMD : M.named_metadata()) {
1805     // Write name.
1806     StringRef Str = NMD.getName();
1807     Record.append(Str.bytes_begin(), Str.bytes_end());
1808     Stream.EmitRecord(bitc::METADATA_NAME, Record, Abbrev);
1809     Record.clear();
1810 
1811     // Write named metadata operands.
1812     for (const MDNode *N : NMD.operands())
1813       Record.push_back(VE.getMetadataID(N));
1814     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
1815     Record.clear();
1816   }
1817 }
1818 
1819 unsigned ModuleBitcodeWriter::createMetadataStringsAbbrev() {
1820   auto Abbv = std::make_shared<BitCodeAbbrev>();
1821   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRINGS));
1822   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // # of strings
1823   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // offset to chars
1824   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
1825   return Stream.EmitAbbrev(std::move(Abbv));
1826 }
1827 
1828 /// Write out a record for MDString.
1829 ///
1830 /// All the metadata strings in a metadata block are emitted in a single
1831 /// record.  The sizes and strings themselves are shoved into a blob.
1832 void ModuleBitcodeWriter::writeMetadataStrings(
1833     ArrayRef<const Metadata *> Strings, SmallVectorImpl<uint64_t> &Record) {
1834   if (Strings.empty())
1835     return;
1836 
1837   // Start the record with the number of strings.
1838   Record.push_back(bitc::METADATA_STRINGS);
1839   Record.push_back(Strings.size());
1840 
1841   // Emit the sizes of the strings in the blob.
1842   SmallString<256> Blob;
1843   {
1844     BitstreamWriter W(Blob);
1845     for (const Metadata *MD : Strings)
1846       W.EmitVBR(cast<MDString>(MD)->getLength(), 6);
1847     W.FlushToWord();
1848   }
1849 
1850   // Add the offset to the strings to the record.
1851   Record.push_back(Blob.size());
1852 
1853   // Add the strings to the blob.
1854   for (const Metadata *MD : Strings)
1855     Blob.append(cast<MDString>(MD)->getString());
1856 
1857   // Emit the final record.
1858   Stream.EmitRecordWithBlob(createMetadataStringsAbbrev(), Record, Blob);
1859   Record.clear();
1860 }
1861 
1862 // Generates an enum to use as an index in the Abbrev array of Metadata record.
1863 enum MetadataAbbrev : unsigned {
1864 #define HANDLE_MDNODE_LEAF(CLASS) CLASS##AbbrevID,
1865 #include "llvm/IR/Metadata.def"
1866   LastPlusOne
1867 };
1868 
1869 void ModuleBitcodeWriter::writeMetadataRecords(
1870     ArrayRef<const Metadata *> MDs, SmallVectorImpl<uint64_t> &Record,
1871     std::vector<unsigned> *MDAbbrevs, std::vector<uint64_t> *IndexPos) {
1872   if (MDs.empty())
1873     return;
1874 
1875   // Initialize MDNode abbreviations.
1876 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
1877 #include "llvm/IR/Metadata.def"
1878 
1879   for (const Metadata *MD : MDs) {
1880     if (IndexPos)
1881       IndexPos->push_back(Stream.GetCurrentBitNo());
1882     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
1883       assert(N->isResolved() && "Expected forward references to be resolved");
1884 
1885       switch (N->getMetadataID()) {
1886       default:
1887         llvm_unreachable("Invalid MDNode subclass");
1888 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
1889   case Metadata::CLASS##Kind:                                                  \
1890     if (MDAbbrevs)                                                             \
1891       write##CLASS(cast<CLASS>(N), Record,                                     \
1892                    (*MDAbbrevs)[MetadataAbbrev::CLASS##AbbrevID]);             \
1893     else                                                                       \
1894       write##CLASS(cast<CLASS>(N), Record, CLASS##Abbrev);                     \
1895     continue;
1896 #include "llvm/IR/Metadata.def"
1897       }
1898     }
1899     writeValueAsMetadata(cast<ValueAsMetadata>(MD), Record);
1900   }
1901 }
1902 
1903 void ModuleBitcodeWriter::writeModuleMetadata() {
1904   if (!VE.hasMDs() && M.named_metadata_empty())
1905     return;
1906 
1907   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 4);
1908   SmallVector<uint64_t, 64> Record;
1909 
1910   // Emit all abbrevs upfront, so that the reader can jump in the middle of the
1911   // block and load any metadata.
1912   std::vector<unsigned> MDAbbrevs;
1913 
1914   MDAbbrevs.resize(MetadataAbbrev::LastPlusOne);
1915   MDAbbrevs[MetadataAbbrev::DILocationAbbrevID] = createDILocationAbbrev();
1916   MDAbbrevs[MetadataAbbrev::GenericDINodeAbbrevID] =
1917       createGenericDINodeAbbrev();
1918 
1919   auto Abbv = std::make_shared<BitCodeAbbrev>();
1920   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX_OFFSET));
1921   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
1922   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
1923   unsigned OffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1924 
1925   Abbv = std::make_shared<BitCodeAbbrev>();
1926   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX));
1927   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1928   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1929   unsigned IndexAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1930 
1931   // Emit MDStrings together upfront.
1932   writeMetadataStrings(VE.getMDStrings(), Record);
1933 
1934   // We only emit an index for the metadata record if we have more than a given
1935   // (naive) threshold of metadatas, otherwise it is not worth it.
1936   if (VE.getNonMDStrings().size() > IndexThreshold) {
1937     // Write a placeholder value in for the offset of the metadata index,
1938     // which is written after the records, so that it can include
1939     // the offset of each entry. The placeholder offset will be
1940     // updated after all records are emitted.
1941     uint64_t Vals[] = {0, 0};
1942     Stream.EmitRecord(bitc::METADATA_INDEX_OFFSET, Vals, OffsetAbbrev);
1943   }
1944 
1945   // Compute and save the bit offset to the current position, which will be
1946   // patched when we emit the index later. We can simply subtract the 64-bit
1947   // fixed size from the current bit number to get the location to backpatch.
1948   uint64_t IndexOffsetRecordBitPos = Stream.GetCurrentBitNo();
1949 
1950   // This index will contain the bitpos for each individual record.
1951   std::vector<uint64_t> IndexPos;
1952   IndexPos.reserve(VE.getNonMDStrings().size());
1953 
1954   // Write all the records
1955   writeMetadataRecords(VE.getNonMDStrings(), Record, &MDAbbrevs, &IndexPos);
1956 
1957   if (VE.getNonMDStrings().size() > IndexThreshold) {
1958     // Now that we have emitted all the records we will emit the index. But
1959     // first
1960     // backpatch the forward reference so that the reader can skip the records
1961     // efficiently.
1962     Stream.BackpatchWord64(IndexOffsetRecordBitPos - 64,
1963                            Stream.GetCurrentBitNo() - IndexOffsetRecordBitPos);
1964 
1965     // Delta encode the index.
1966     uint64_t PreviousValue = IndexOffsetRecordBitPos;
1967     for (auto &Elt : IndexPos) {
1968       auto EltDelta = Elt - PreviousValue;
1969       PreviousValue = Elt;
1970       Elt = EltDelta;
1971     }
1972     // Emit the index record.
1973     Stream.EmitRecord(bitc::METADATA_INDEX, IndexPos, IndexAbbrev);
1974     IndexPos.clear();
1975   }
1976 
1977   // Write the named metadata now.
1978   writeNamedMetadata(Record);
1979 
1980   auto AddDeclAttachedMetadata = [&](const GlobalObject &GO) {
1981     SmallVector<uint64_t, 4> Record;
1982     Record.push_back(VE.getValueID(&GO));
1983     pushGlobalMetadataAttachment(Record, GO);
1984     Stream.EmitRecord(bitc::METADATA_GLOBAL_DECL_ATTACHMENT, Record);
1985   };
1986   for (const Function &F : M)
1987     if (F.isDeclaration() && F.hasMetadata())
1988       AddDeclAttachedMetadata(F);
1989   // FIXME: Only store metadata for declarations here, and move data for global
1990   // variable definitions to a separate block (PR28134).
1991   for (const GlobalVariable &GV : M.globals())
1992     if (GV.hasMetadata())
1993       AddDeclAttachedMetadata(GV);
1994 
1995   Stream.ExitBlock();
1996 }
1997 
1998 void ModuleBitcodeWriter::writeFunctionMetadata(const Function &F) {
1999   if (!VE.hasMDs())
2000     return;
2001 
2002   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
2003   SmallVector<uint64_t, 64> Record;
2004   writeMetadataStrings(VE.getMDStrings(), Record);
2005   writeMetadataRecords(VE.getNonMDStrings(), Record);
2006   Stream.ExitBlock();
2007 }
2008 
2009 void ModuleBitcodeWriter::pushGlobalMetadataAttachment(
2010     SmallVectorImpl<uint64_t> &Record, const GlobalObject &GO) {
2011   // [n x [id, mdnode]]
2012   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2013   GO.getAllMetadata(MDs);
2014   for (const auto &I : MDs) {
2015     Record.push_back(I.first);
2016     Record.push_back(VE.getMetadataID(I.second));
2017   }
2018 }
2019 
2020 void ModuleBitcodeWriter::writeFunctionMetadataAttachment(const Function &F) {
2021   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
2022 
2023   SmallVector<uint64_t, 64> Record;
2024 
2025   if (F.hasMetadata()) {
2026     pushGlobalMetadataAttachment(Record, F);
2027     Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2028     Record.clear();
2029   }
2030 
2031   // Write metadata attachments
2032   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
2033   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2034   for (const BasicBlock &BB : F)
2035     for (const Instruction &I : BB) {
2036       MDs.clear();
2037       I.getAllMetadataOtherThanDebugLoc(MDs);
2038 
2039       // If no metadata, ignore instruction.
2040       if (MDs.empty()) continue;
2041 
2042       Record.push_back(VE.getInstructionID(&I));
2043 
2044       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
2045         Record.push_back(MDs[i].first);
2046         Record.push_back(VE.getMetadataID(MDs[i].second));
2047       }
2048       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2049       Record.clear();
2050     }
2051 
2052   Stream.ExitBlock();
2053 }
2054 
2055 void ModuleBitcodeWriter::writeModuleMetadataKinds() {
2056   SmallVector<uint64_t, 64> Record;
2057 
2058   // Write metadata kinds
2059   // METADATA_KIND - [n x [id, name]]
2060   SmallVector<StringRef, 8> Names;
2061   M.getMDKindNames(Names);
2062 
2063   if (Names.empty()) return;
2064 
2065   Stream.EnterSubblock(bitc::METADATA_KIND_BLOCK_ID, 3);
2066 
2067   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
2068     Record.push_back(MDKindID);
2069     StringRef KName = Names[MDKindID];
2070     Record.append(KName.begin(), KName.end());
2071 
2072     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
2073     Record.clear();
2074   }
2075 
2076   Stream.ExitBlock();
2077 }
2078 
2079 void ModuleBitcodeWriter::writeOperandBundleTags() {
2080   // Write metadata kinds
2081   //
2082   // OPERAND_BUNDLE_TAGS_BLOCK_ID : N x OPERAND_BUNDLE_TAG
2083   //
2084   // OPERAND_BUNDLE_TAG - [strchr x N]
2085 
2086   SmallVector<StringRef, 8> Tags;
2087   M.getOperandBundleTags(Tags);
2088 
2089   if (Tags.empty())
2090     return;
2091 
2092   Stream.EnterSubblock(bitc::OPERAND_BUNDLE_TAGS_BLOCK_ID, 3);
2093 
2094   SmallVector<uint64_t, 64> Record;
2095 
2096   for (auto Tag : Tags) {
2097     Record.append(Tag.begin(), Tag.end());
2098 
2099     Stream.EmitRecord(bitc::OPERAND_BUNDLE_TAG, Record, 0);
2100     Record.clear();
2101   }
2102 
2103   Stream.ExitBlock();
2104 }
2105 
2106 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
2107   if ((int64_t)V >= 0)
2108     Vals.push_back(V << 1);
2109   else
2110     Vals.push_back((-V << 1) | 1);
2111 }
2112 
2113 void ModuleBitcodeWriter::writeConstants(unsigned FirstVal, unsigned LastVal,
2114                                          bool isGlobal) {
2115   if (FirstVal == LastVal) return;
2116 
2117   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
2118 
2119   unsigned AggregateAbbrev = 0;
2120   unsigned String8Abbrev = 0;
2121   unsigned CString7Abbrev = 0;
2122   unsigned CString6Abbrev = 0;
2123   // If this is a constant pool for the module, emit module-specific abbrevs.
2124   if (isGlobal) {
2125     // Abbrev for CST_CODE_AGGREGATE.
2126     auto Abbv = std::make_shared<BitCodeAbbrev>();
2127     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
2128     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2129     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
2130     AggregateAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2131 
2132     // Abbrev for CST_CODE_STRING.
2133     Abbv = std::make_shared<BitCodeAbbrev>();
2134     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
2135     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2136     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2137     String8Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2138     // Abbrev for CST_CODE_CSTRING.
2139     Abbv = std::make_shared<BitCodeAbbrev>();
2140     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2141     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2142     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2143     CString7Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2144     // Abbrev for CST_CODE_CSTRING.
2145     Abbv = std::make_shared<BitCodeAbbrev>();
2146     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2147     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2148     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2149     CString6Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2150   }
2151 
2152   SmallVector<uint64_t, 64> Record;
2153 
2154   const ValueEnumerator::ValueList &Vals = VE.getValues();
2155   Type *LastTy = nullptr;
2156   for (unsigned i = FirstVal; i != LastVal; ++i) {
2157     const Value *V = Vals[i].first;
2158     // If we need to switch types, do so now.
2159     if (V->getType() != LastTy) {
2160       LastTy = V->getType();
2161       Record.push_back(VE.getTypeID(LastTy));
2162       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
2163                         CONSTANTS_SETTYPE_ABBREV);
2164       Record.clear();
2165     }
2166 
2167     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
2168       Record.push_back(unsigned(IA->hasSideEffects()) |
2169                        unsigned(IA->isAlignStack()) << 1 |
2170                        unsigned(IA->getDialect()&1) << 2);
2171 
2172       // Add the asm string.
2173       const std::string &AsmStr = IA->getAsmString();
2174       Record.push_back(AsmStr.size());
2175       Record.append(AsmStr.begin(), AsmStr.end());
2176 
2177       // Add the constraint string.
2178       const std::string &ConstraintStr = IA->getConstraintString();
2179       Record.push_back(ConstraintStr.size());
2180       Record.append(ConstraintStr.begin(), ConstraintStr.end());
2181       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
2182       Record.clear();
2183       continue;
2184     }
2185     const Constant *C = cast<Constant>(V);
2186     unsigned Code = -1U;
2187     unsigned AbbrevToUse = 0;
2188     if (C->isNullValue()) {
2189       Code = bitc::CST_CODE_NULL;
2190     } else if (isa<UndefValue>(C)) {
2191       Code = bitc::CST_CODE_UNDEF;
2192     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
2193       if (IV->getBitWidth() <= 64) {
2194         uint64_t V = IV->getSExtValue();
2195         emitSignedInt64(Record, V);
2196         Code = bitc::CST_CODE_INTEGER;
2197         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
2198       } else {                             // Wide integers, > 64 bits in size.
2199         // We have an arbitrary precision integer value to write whose
2200         // bit width is > 64. However, in canonical unsigned integer
2201         // format it is likely that the high bits are going to be zero.
2202         // So, we only write the number of active words.
2203         unsigned NWords = IV->getValue().getActiveWords();
2204         const uint64_t *RawWords = IV->getValue().getRawData();
2205         for (unsigned i = 0; i != NWords; ++i) {
2206           emitSignedInt64(Record, RawWords[i]);
2207         }
2208         Code = bitc::CST_CODE_WIDE_INTEGER;
2209       }
2210     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
2211       Code = bitc::CST_CODE_FLOAT;
2212       Type *Ty = CFP->getType();
2213       if (Ty->isHalfTy() || Ty->isFloatTy() || Ty->isDoubleTy()) {
2214         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
2215       } else if (Ty->isX86_FP80Ty()) {
2216         // api needed to prevent premature destruction
2217         // bits are not in the same order as a normal i80 APInt, compensate.
2218         APInt api = CFP->getValueAPF().bitcastToAPInt();
2219         const uint64_t *p = api.getRawData();
2220         Record.push_back((p[1] << 48) | (p[0] >> 16));
2221         Record.push_back(p[0] & 0xffffLL);
2222       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
2223         APInt api = CFP->getValueAPF().bitcastToAPInt();
2224         const uint64_t *p = api.getRawData();
2225         Record.push_back(p[0]);
2226         Record.push_back(p[1]);
2227       } else {
2228         assert (0 && "Unknown FP type!");
2229       }
2230     } else if (isa<ConstantDataSequential>(C) &&
2231                cast<ConstantDataSequential>(C)->isString()) {
2232       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
2233       // Emit constant strings specially.
2234       unsigned NumElts = Str->getNumElements();
2235       // If this is a null-terminated string, use the denser CSTRING encoding.
2236       if (Str->isCString()) {
2237         Code = bitc::CST_CODE_CSTRING;
2238         --NumElts;  // Don't encode the null, which isn't allowed by char6.
2239       } else {
2240         Code = bitc::CST_CODE_STRING;
2241         AbbrevToUse = String8Abbrev;
2242       }
2243       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
2244       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
2245       for (unsigned i = 0; i != NumElts; ++i) {
2246         unsigned char V = Str->getElementAsInteger(i);
2247         Record.push_back(V);
2248         isCStr7 &= (V & 128) == 0;
2249         if (isCStrChar6)
2250           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
2251       }
2252 
2253       if (isCStrChar6)
2254         AbbrevToUse = CString6Abbrev;
2255       else if (isCStr7)
2256         AbbrevToUse = CString7Abbrev;
2257     } else if (const ConstantDataSequential *CDS =
2258                   dyn_cast<ConstantDataSequential>(C)) {
2259       Code = bitc::CST_CODE_DATA;
2260       Type *EltTy = CDS->getType()->getElementType();
2261       if (isa<IntegerType>(EltTy)) {
2262         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2263           Record.push_back(CDS->getElementAsInteger(i));
2264       } else {
2265         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2266           Record.push_back(
2267               CDS->getElementAsAPFloat(i).bitcastToAPInt().getLimitedValue());
2268       }
2269     } else if (isa<ConstantAggregate>(C)) {
2270       Code = bitc::CST_CODE_AGGREGATE;
2271       for (const Value *Op : C->operands())
2272         Record.push_back(VE.getValueID(Op));
2273       AbbrevToUse = AggregateAbbrev;
2274     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
2275       switch (CE->getOpcode()) {
2276       default:
2277         if (Instruction::isCast(CE->getOpcode())) {
2278           Code = bitc::CST_CODE_CE_CAST;
2279           Record.push_back(getEncodedCastOpcode(CE->getOpcode()));
2280           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2281           Record.push_back(VE.getValueID(C->getOperand(0)));
2282           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
2283         } else {
2284           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
2285           Code = bitc::CST_CODE_CE_BINOP;
2286           Record.push_back(getEncodedBinaryOpcode(CE->getOpcode()));
2287           Record.push_back(VE.getValueID(C->getOperand(0)));
2288           Record.push_back(VE.getValueID(C->getOperand(1)));
2289           uint64_t Flags = getOptimizationFlags(CE);
2290           if (Flags != 0)
2291             Record.push_back(Flags);
2292         }
2293         break;
2294       case Instruction::GetElementPtr: {
2295         Code = bitc::CST_CODE_CE_GEP;
2296         const auto *GO = cast<GEPOperator>(C);
2297         Record.push_back(VE.getTypeID(GO->getSourceElementType()));
2298         if (Optional<unsigned> Idx = GO->getInRangeIndex()) {
2299           Code = bitc::CST_CODE_CE_GEP_WITH_INRANGE_INDEX;
2300           Record.push_back((*Idx << 1) | GO->isInBounds());
2301         } else if (GO->isInBounds())
2302           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
2303         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
2304           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
2305           Record.push_back(VE.getValueID(C->getOperand(i)));
2306         }
2307         break;
2308       }
2309       case Instruction::Select:
2310         Code = bitc::CST_CODE_CE_SELECT;
2311         Record.push_back(VE.getValueID(C->getOperand(0)));
2312         Record.push_back(VE.getValueID(C->getOperand(1)));
2313         Record.push_back(VE.getValueID(C->getOperand(2)));
2314         break;
2315       case Instruction::ExtractElement:
2316         Code = bitc::CST_CODE_CE_EXTRACTELT;
2317         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2318         Record.push_back(VE.getValueID(C->getOperand(0)));
2319         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
2320         Record.push_back(VE.getValueID(C->getOperand(1)));
2321         break;
2322       case Instruction::InsertElement:
2323         Code = bitc::CST_CODE_CE_INSERTELT;
2324         Record.push_back(VE.getValueID(C->getOperand(0)));
2325         Record.push_back(VE.getValueID(C->getOperand(1)));
2326         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
2327         Record.push_back(VE.getValueID(C->getOperand(2)));
2328         break;
2329       case Instruction::ShuffleVector:
2330         // If the return type and argument types are the same, this is a
2331         // standard shufflevector instruction.  If the types are different,
2332         // then the shuffle is widening or truncating the input vectors, and
2333         // the argument type must also be encoded.
2334         if (C->getType() == C->getOperand(0)->getType()) {
2335           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
2336         } else {
2337           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
2338           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2339         }
2340         Record.push_back(VE.getValueID(C->getOperand(0)));
2341         Record.push_back(VE.getValueID(C->getOperand(1)));
2342         Record.push_back(VE.getValueID(C->getOperand(2)));
2343         break;
2344       case Instruction::ICmp:
2345       case Instruction::FCmp:
2346         Code = bitc::CST_CODE_CE_CMP;
2347         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2348         Record.push_back(VE.getValueID(C->getOperand(0)));
2349         Record.push_back(VE.getValueID(C->getOperand(1)));
2350         Record.push_back(CE->getPredicate());
2351         break;
2352       }
2353     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
2354       Code = bitc::CST_CODE_BLOCKADDRESS;
2355       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
2356       Record.push_back(VE.getValueID(BA->getFunction()));
2357       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
2358     } else {
2359 #ifndef NDEBUG
2360       C->dump();
2361 #endif
2362       llvm_unreachable("Unknown constant!");
2363     }
2364     Stream.EmitRecord(Code, Record, AbbrevToUse);
2365     Record.clear();
2366   }
2367 
2368   Stream.ExitBlock();
2369 }
2370 
2371 void ModuleBitcodeWriter::writeModuleConstants() {
2372   const ValueEnumerator::ValueList &Vals = VE.getValues();
2373 
2374   // Find the first constant to emit, which is the first non-globalvalue value.
2375   // We know globalvalues have been emitted by WriteModuleInfo.
2376   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
2377     if (!isa<GlobalValue>(Vals[i].first)) {
2378       writeConstants(i, Vals.size(), true);
2379       return;
2380     }
2381   }
2382 }
2383 
2384 /// pushValueAndType - The file has to encode both the value and type id for
2385 /// many values, because we need to know what type to create for forward
2386 /// references.  However, most operands are not forward references, so this type
2387 /// field is not needed.
2388 ///
2389 /// This function adds V's value ID to Vals.  If the value ID is higher than the
2390 /// instruction ID, then it is a forward reference, and it also includes the
2391 /// type ID.  The value ID that is written is encoded relative to the InstID.
2392 bool ModuleBitcodeWriter::pushValueAndType(const Value *V, unsigned InstID,
2393                                            SmallVectorImpl<unsigned> &Vals) {
2394   unsigned ValID = VE.getValueID(V);
2395   // Make encoding relative to the InstID.
2396   Vals.push_back(InstID - ValID);
2397   if (ValID >= InstID) {
2398     Vals.push_back(VE.getTypeID(V->getType()));
2399     return true;
2400   }
2401   return false;
2402 }
2403 
2404 void ModuleBitcodeWriter::writeOperandBundles(ImmutableCallSite CS,
2405                                               unsigned InstID) {
2406   SmallVector<unsigned, 64> Record;
2407   LLVMContext &C = CS.getInstruction()->getContext();
2408 
2409   for (unsigned i = 0, e = CS.getNumOperandBundles(); i != e; ++i) {
2410     const auto &Bundle = CS.getOperandBundleAt(i);
2411     Record.push_back(C.getOperandBundleTagID(Bundle.getTagName()));
2412 
2413     for (auto &Input : Bundle.Inputs)
2414       pushValueAndType(Input, InstID, Record);
2415 
2416     Stream.EmitRecord(bitc::FUNC_CODE_OPERAND_BUNDLE, Record);
2417     Record.clear();
2418   }
2419 }
2420 
2421 /// pushValue - Like pushValueAndType, but where the type of the value is
2422 /// omitted (perhaps it was already encoded in an earlier operand).
2423 void ModuleBitcodeWriter::pushValue(const Value *V, unsigned InstID,
2424                                     SmallVectorImpl<unsigned> &Vals) {
2425   unsigned ValID = VE.getValueID(V);
2426   Vals.push_back(InstID - ValID);
2427 }
2428 
2429 void ModuleBitcodeWriter::pushValueSigned(const Value *V, unsigned InstID,
2430                                           SmallVectorImpl<uint64_t> &Vals) {
2431   unsigned ValID = VE.getValueID(V);
2432   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
2433   emitSignedInt64(Vals, diff);
2434 }
2435 
2436 /// WriteInstruction - Emit an instruction to the specified stream.
2437 void ModuleBitcodeWriter::writeInstruction(const Instruction &I,
2438                                            unsigned InstID,
2439                                            SmallVectorImpl<unsigned> &Vals) {
2440   unsigned Code = 0;
2441   unsigned AbbrevToUse = 0;
2442   VE.setInstructionID(&I);
2443   switch (I.getOpcode()) {
2444   default:
2445     if (Instruction::isCast(I.getOpcode())) {
2446       Code = bitc::FUNC_CODE_INST_CAST;
2447       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2448         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
2449       Vals.push_back(VE.getTypeID(I.getType()));
2450       Vals.push_back(getEncodedCastOpcode(I.getOpcode()));
2451     } else {
2452       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
2453       Code = bitc::FUNC_CODE_INST_BINOP;
2454       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2455         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
2456       pushValue(I.getOperand(1), InstID, Vals);
2457       Vals.push_back(getEncodedBinaryOpcode(I.getOpcode()));
2458       uint64_t Flags = getOptimizationFlags(&I);
2459       if (Flags != 0) {
2460         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
2461           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
2462         Vals.push_back(Flags);
2463       }
2464     }
2465     break;
2466 
2467   case Instruction::GetElementPtr: {
2468     Code = bitc::FUNC_CODE_INST_GEP;
2469     AbbrevToUse = FUNCTION_INST_GEP_ABBREV;
2470     auto &GEPInst = cast<GetElementPtrInst>(I);
2471     Vals.push_back(GEPInst.isInBounds());
2472     Vals.push_back(VE.getTypeID(GEPInst.getSourceElementType()));
2473     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
2474       pushValueAndType(I.getOperand(i), InstID, Vals);
2475     break;
2476   }
2477   case Instruction::ExtractValue: {
2478     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
2479     pushValueAndType(I.getOperand(0), InstID, Vals);
2480     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
2481     Vals.append(EVI->idx_begin(), EVI->idx_end());
2482     break;
2483   }
2484   case Instruction::InsertValue: {
2485     Code = bitc::FUNC_CODE_INST_INSERTVAL;
2486     pushValueAndType(I.getOperand(0), InstID, Vals);
2487     pushValueAndType(I.getOperand(1), InstID, Vals);
2488     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
2489     Vals.append(IVI->idx_begin(), IVI->idx_end());
2490     break;
2491   }
2492   case Instruction::Select:
2493     Code = bitc::FUNC_CODE_INST_VSELECT;
2494     pushValueAndType(I.getOperand(1), InstID, Vals);
2495     pushValue(I.getOperand(2), InstID, Vals);
2496     pushValueAndType(I.getOperand(0), InstID, Vals);
2497     break;
2498   case Instruction::ExtractElement:
2499     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
2500     pushValueAndType(I.getOperand(0), InstID, Vals);
2501     pushValueAndType(I.getOperand(1), InstID, Vals);
2502     break;
2503   case Instruction::InsertElement:
2504     Code = bitc::FUNC_CODE_INST_INSERTELT;
2505     pushValueAndType(I.getOperand(0), InstID, Vals);
2506     pushValue(I.getOperand(1), InstID, Vals);
2507     pushValueAndType(I.getOperand(2), InstID, Vals);
2508     break;
2509   case Instruction::ShuffleVector:
2510     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
2511     pushValueAndType(I.getOperand(0), InstID, Vals);
2512     pushValue(I.getOperand(1), InstID, Vals);
2513     pushValue(I.getOperand(2), InstID, Vals);
2514     break;
2515   case Instruction::ICmp:
2516   case Instruction::FCmp: {
2517     // compare returning Int1Ty or vector of Int1Ty
2518     Code = bitc::FUNC_CODE_INST_CMP2;
2519     pushValueAndType(I.getOperand(0), InstID, Vals);
2520     pushValue(I.getOperand(1), InstID, Vals);
2521     Vals.push_back(cast<CmpInst>(I).getPredicate());
2522     uint64_t Flags = getOptimizationFlags(&I);
2523     if (Flags != 0)
2524       Vals.push_back(Flags);
2525     break;
2526   }
2527 
2528   case Instruction::Ret:
2529     {
2530       Code = bitc::FUNC_CODE_INST_RET;
2531       unsigned NumOperands = I.getNumOperands();
2532       if (NumOperands == 0)
2533         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
2534       else if (NumOperands == 1) {
2535         if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2536           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
2537       } else {
2538         for (unsigned i = 0, e = NumOperands; i != e; ++i)
2539           pushValueAndType(I.getOperand(i), InstID, Vals);
2540       }
2541     }
2542     break;
2543   case Instruction::Br:
2544     {
2545       Code = bitc::FUNC_CODE_INST_BR;
2546       const BranchInst &II = cast<BranchInst>(I);
2547       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
2548       if (II.isConditional()) {
2549         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
2550         pushValue(II.getCondition(), InstID, Vals);
2551       }
2552     }
2553     break;
2554   case Instruction::Switch:
2555     {
2556       Code = bitc::FUNC_CODE_INST_SWITCH;
2557       const SwitchInst &SI = cast<SwitchInst>(I);
2558       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
2559       pushValue(SI.getCondition(), InstID, Vals);
2560       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
2561       for (SwitchInst::ConstCaseIt Case : SI.cases()) {
2562         Vals.push_back(VE.getValueID(Case.getCaseValue()));
2563         Vals.push_back(VE.getValueID(Case.getCaseSuccessor()));
2564       }
2565     }
2566     break;
2567   case Instruction::IndirectBr:
2568     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
2569     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2570     // Encode the address operand as relative, but not the basic blocks.
2571     pushValue(I.getOperand(0), InstID, Vals);
2572     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
2573       Vals.push_back(VE.getValueID(I.getOperand(i)));
2574     break;
2575 
2576   case Instruction::Invoke: {
2577     const InvokeInst *II = cast<InvokeInst>(&I);
2578     const Value *Callee = II->getCalledValue();
2579     FunctionType *FTy = II->getFunctionType();
2580 
2581     if (II->hasOperandBundles())
2582       writeOperandBundles(II, InstID);
2583 
2584     Code = bitc::FUNC_CODE_INST_INVOKE;
2585 
2586     Vals.push_back(VE.getAttributeID(II->getAttributes()));
2587     Vals.push_back(II->getCallingConv() | 1 << 13);
2588     Vals.push_back(VE.getValueID(II->getNormalDest()));
2589     Vals.push_back(VE.getValueID(II->getUnwindDest()));
2590     Vals.push_back(VE.getTypeID(FTy));
2591     pushValueAndType(Callee, InstID, Vals);
2592 
2593     // Emit value #'s for the fixed parameters.
2594     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
2595       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
2596 
2597     // Emit type/value pairs for varargs params.
2598     if (FTy->isVarArg()) {
2599       for (unsigned i = FTy->getNumParams(), e = II->getNumArgOperands();
2600            i != e; ++i)
2601         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
2602     }
2603     break;
2604   }
2605   case Instruction::Resume:
2606     Code = bitc::FUNC_CODE_INST_RESUME;
2607     pushValueAndType(I.getOperand(0), InstID, Vals);
2608     break;
2609   case Instruction::CleanupRet: {
2610     Code = bitc::FUNC_CODE_INST_CLEANUPRET;
2611     const auto &CRI = cast<CleanupReturnInst>(I);
2612     pushValue(CRI.getCleanupPad(), InstID, Vals);
2613     if (CRI.hasUnwindDest())
2614       Vals.push_back(VE.getValueID(CRI.getUnwindDest()));
2615     break;
2616   }
2617   case Instruction::CatchRet: {
2618     Code = bitc::FUNC_CODE_INST_CATCHRET;
2619     const auto &CRI = cast<CatchReturnInst>(I);
2620     pushValue(CRI.getCatchPad(), InstID, Vals);
2621     Vals.push_back(VE.getValueID(CRI.getSuccessor()));
2622     break;
2623   }
2624   case Instruction::CleanupPad:
2625   case Instruction::CatchPad: {
2626     const auto &FuncletPad = cast<FuncletPadInst>(I);
2627     Code = isa<CatchPadInst>(FuncletPad) ? bitc::FUNC_CODE_INST_CATCHPAD
2628                                          : bitc::FUNC_CODE_INST_CLEANUPPAD;
2629     pushValue(FuncletPad.getParentPad(), InstID, Vals);
2630 
2631     unsigned NumArgOperands = FuncletPad.getNumArgOperands();
2632     Vals.push_back(NumArgOperands);
2633     for (unsigned Op = 0; Op != NumArgOperands; ++Op)
2634       pushValueAndType(FuncletPad.getArgOperand(Op), InstID, Vals);
2635     break;
2636   }
2637   case Instruction::CatchSwitch: {
2638     Code = bitc::FUNC_CODE_INST_CATCHSWITCH;
2639     const auto &CatchSwitch = cast<CatchSwitchInst>(I);
2640 
2641     pushValue(CatchSwitch.getParentPad(), InstID, Vals);
2642 
2643     unsigned NumHandlers = CatchSwitch.getNumHandlers();
2644     Vals.push_back(NumHandlers);
2645     for (const BasicBlock *CatchPadBB : CatchSwitch.handlers())
2646       Vals.push_back(VE.getValueID(CatchPadBB));
2647 
2648     if (CatchSwitch.hasUnwindDest())
2649       Vals.push_back(VE.getValueID(CatchSwitch.getUnwindDest()));
2650     break;
2651   }
2652   case Instruction::Unreachable:
2653     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
2654     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
2655     break;
2656 
2657   case Instruction::PHI: {
2658     const PHINode &PN = cast<PHINode>(I);
2659     Code = bitc::FUNC_CODE_INST_PHI;
2660     // With the newer instruction encoding, forward references could give
2661     // negative valued IDs.  This is most common for PHIs, so we use
2662     // signed VBRs.
2663     SmallVector<uint64_t, 128> Vals64;
2664     Vals64.push_back(VE.getTypeID(PN.getType()));
2665     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
2666       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64);
2667       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
2668     }
2669     // Emit a Vals64 vector and exit.
2670     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
2671     Vals64.clear();
2672     return;
2673   }
2674 
2675   case Instruction::LandingPad: {
2676     const LandingPadInst &LP = cast<LandingPadInst>(I);
2677     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
2678     Vals.push_back(VE.getTypeID(LP.getType()));
2679     Vals.push_back(LP.isCleanup());
2680     Vals.push_back(LP.getNumClauses());
2681     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
2682       if (LP.isCatch(I))
2683         Vals.push_back(LandingPadInst::Catch);
2684       else
2685         Vals.push_back(LandingPadInst::Filter);
2686       pushValueAndType(LP.getClause(I), InstID, Vals);
2687     }
2688     break;
2689   }
2690 
2691   case Instruction::Alloca: {
2692     Code = bitc::FUNC_CODE_INST_ALLOCA;
2693     const AllocaInst &AI = cast<AllocaInst>(I);
2694     Vals.push_back(VE.getTypeID(AI.getAllocatedType()));
2695     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2696     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
2697     unsigned AlignRecord = Log2_32(AI.getAlignment()) + 1;
2698     assert(Log2_32(Value::MaximumAlignment) + 1 < 1 << 5 &&
2699            "not enough bits for maximum alignment");
2700     assert(AlignRecord < 1 << 5 && "alignment greater than 1 << 64");
2701     AlignRecord |= AI.isUsedWithInAlloca() << 5;
2702     AlignRecord |= 1 << 6;
2703     AlignRecord |= AI.isSwiftError() << 7;
2704     Vals.push_back(AlignRecord);
2705     break;
2706   }
2707 
2708   case Instruction::Load:
2709     if (cast<LoadInst>(I).isAtomic()) {
2710       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
2711       pushValueAndType(I.getOperand(0), InstID, Vals);
2712     } else {
2713       Code = bitc::FUNC_CODE_INST_LOAD;
2714       if (!pushValueAndType(I.getOperand(0), InstID, Vals)) // ptr
2715         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
2716     }
2717     Vals.push_back(VE.getTypeID(I.getType()));
2718     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
2719     Vals.push_back(cast<LoadInst>(I).isVolatile());
2720     if (cast<LoadInst>(I).isAtomic()) {
2721       Vals.push_back(getEncodedOrdering(cast<LoadInst>(I).getOrdering()));
2722       Vals.push_back(getEncodedSynchScope(cast<LoadInst>(I).getSynchScope()));
2723     }
2724     break;
2725   case Instruction::Store:
2726     if (cast<StoreInst>(I).isAtomic())
2727       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
2728     else
2729       Code = bitc::FUNC_CODE_INST_STORE;
2730     pushValueAndType(I.getOperand(1), InstID, Vals); // ptrty + ptr
2731     pushValueAndType(I.getOperand(0), InstID, Vals); // valty + val
2732     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
2733     Vals.push_back(cast<StoreInst>(I).isVolatile());
2734     if (cast<StoreInst>(I).isAtomic()) {
2735       Vals.push_back(getEncodedOrdering(cast<StoreInst>(I).getOrdering()));
2736       Vals.push_back(getEncodedSynchScope(cast<StoreInst>(I).getSynchScope()));
2737     }
2738     break;
2739   case Instruction::AtomicCmpXchg:
2740     Code = bitc::FUNC_CODE_INST_CMPXCHG;
2741     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
2742     pushValueAndType(I.getOperand(1), InstID, Vals); // cmp.
2743     pushValue(I.getOperand(2), InstID, Vals);        // newval.
2744     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
2745     Vals.push_back(
2746         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
2747     Vals.push_back(
2748         getEncodedSynchScope(cast<AtomicCmpXchgInst>(I).getSynchScope()));
2749     Vals.push_back(
2750         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
2751     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
2752     break;
2753   case Instruction::AtomicRMW:
2754     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
2755     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
2756     pushValue(I.getOperand(1), InstID, Vals);        // val.
2757     Vals.push_back(
2758         getEncodedRMWOperation(cast<AtomicRMWInst>(I).getOperation()));
2759     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
2760     Vals.push_back(getEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
2761     Vals.push_back(
2762         getEncodedSynchScope(cast<AtomicRMWInst>(I).getSynchScope()));
2763     break;
2764   case Instruction::Fence:
2765     Code = bitc::FUNC_CODE_INST_FENCE;
2766     Vals.push_back(getEncodedOrdering(cast<FenceInst>(I).getOrdering()));
2767     Vals.push_back(getEncodedSynchScope(cast<FenceInst>(I).getSynchScope()));
2768     break;
2769   case Instruction::Call: {
2770     const CallInst &CI = cast<CallInst>(I);
2771     FunctionType *FTy = CI.getFunctionType();
2772 
2773     if (CI.hasOperandBundles())
2774       writeOperandBundles(&CI, InstID);
2775 
2776     Code = bitc::FUNC_CODE_INST_CALL;
2777 
2778     Vals.push_back(VE.getAttributeID(CI.getAttributes()));
2779 
2780     unsigned Flags = getOptimizationFlags(&I);
2781     Vals.push_back(CI.getCallingConv() << bitc::CALL_CCONV |
2782                    unsigned(CI.isTailCall()) << bitc::CALL_TAIL |
2783                    unsigned(CI.isMustTailCall()) << bitc::CALL_MUSTTAIL |
2784                    1 << bitc::CALL_EXPLICIT_TYPE |
2785                    unsigned(CI.isNoTailCall()) << bitc::CALL_NOTAIL |
2786                    unsigned(Flags != 0) << bitc::CALL_FMF);
2787     if (Flags != 0)
2788       Vals.push_back(Flags);
2789 
2790     Vals.push_back(VE.getTypeID(FTy));
2791     pushValueAndType(CI.getCalledValue(), InstID, Vals); // Callee
2792 
2793     // Emit value #'s for the fixed parameters.
2794     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
2795       // Check for labels (can happen with asm labels).
2796       if (FTy->getParamType(i)->isLabelTy())
2797         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
2798       else
2799         pushValue(CI.getArgOperand(i), InstID, Vals); // fixed param.
2800     }
2801 
2802     // Emit type/value pairs for varargs params.
2803     if (FTy->isVarArg()) {
2804       for (unsigned i = FTy->getNumParams(), e = CI.getNumArgOperands();
2805            i != e; ++i)
2806         pushValueAndType(CI.getArgOperand(i), InstID, Vals); // varargs
2807     }
2808     break;
2809   }
2810   case Instruction::VAArg:
2811     Code = bitc::FUNC_CODE_INST_VAARG;
2812     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
2813     pushValue(I.getOperand(0), InstID, Vals);                   // valist.
2814     Vals.push_back(VE.getTypeID(I.getType())); // restype.
2815     break;
2816   }
2817 
2818   Stream.EmitRecord(Code, Vals, AbbrevToUse);
2819   Vals.clear();
2820 }
2821 
2822 /// Emit names for globals/functions etc. \p IsModuleLevel is true when
2823 /// we are writing the module-level VST, where we are including a function
2824 /// bitcode index and need to backpatch the VST forward declaration record.
2825 void ModuleBitcodeWriter::writeValueSymbolTable(
2826     const ValueSymbolTable &VST, bool IsModuleLevel,
2827     DenseMap<const Function *, uint64_t> *FunctionToBitcodeIndex) {
2828   if (VST.empty()) {
2829     // writeValueSymbolTableForwardDecl should have returned early as
2830     // well. Ensure this handling remains in sync by asserting that
2831     // the placeholder offset is not set.
2832     assert(!IsModuleLevel || !hasVSTOffsetPlaceholder());
2833     return;
2834   }
2835 
2836   if (IsModuleLevel && hasVSTOffsetPlaceholder()) {
2837     // Get the offset of the VST we are writing, and backpatch it into
2838     // the VST forward declaration record.
2839     uint64_t VSTOffset = Stream.GetCurrentBitNo();
2840     // The BitcodeStartBit was the stream offset of the identification block.
2841     VSTOffset -= bitcodeStartBit();
2842     assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
2843     // Note that we add 1 here because the offset is relative to one word
2844     // before the start of the identification block, which was historically
2845     // always the start of the regular bitcode header.
2846     Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32 + 1);
2847   }
2848 
2849   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
2850 
2851   // For the module-level VST, add abbrev Ids for the VST_CODE_FNENTRY
2852   // records, which are not used in the per-function VSTs.
2853   unsigned FnEntry8BitAbbrev;
2854   unsigned FnEntry7BitAbbrev;
2855   unsigned FnEntry6BitAbbrev;
2856   unsigned GUIDEntryAbbrev;
2857   if (IsModuleLevel && hasVSTOffsetPlaceholder()) {
2858     // 8-bit fixed-width VST_CODE_FNENTRY function strings.
2859     auto Abbv = std::make_shared<BitCodeAbbrev>();
2860     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
2861     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
2862     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
2863     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2864     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2865     FnEntry8BitAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2866 
2867     // 7-bit fixed width VST_CODE_FNENTRY function strings.
2868     Abbv = std::make_shared<BitCodeAbbrev>();
2869     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
2870     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
2871     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
2872     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2873     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2874     FnEntry7BitAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2875 
2876     // 6-bit char6 VST_CODE_FNENTRY function strings.
2877     Abbv = std::make_shared<BitCodeAbbrev>();
2878     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
2879     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
2880     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
2881     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2882     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2883     FnEntry6BitAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2884 
2885     // FIXME: Change the name of this record as it is now used by
2886     // the per-module index as well.
2887     Abbv = std::make_shared<BitCodeAbbrev>();
2888     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_COMBINED_ENTRY));
2889     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
2890     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // refguid
2891     GUIDEntryAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2892   }
2893 
2894   // FIXME: Set up the abbrev, we know how many values there are!
2895   // FIXME: We know if the type names can use 7-bit ascii.
2896   SmallVector<uint64_t, 64> NameVals;
2897 
2898   for (const ValueName &Name : VST) {
2899     // Figure out the encoding to use for the name.
2900     StringEncoding Bits =
2901         getStringEncoding(Name.getKeyData(), Name.getKeyLength());
2902 
2903     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
2904     NameVals.push_back(VE.getValueID(Name.getValue()));
2905 
2906     Function *F = dyn_cast<Function>(Name.getValue());
2907     if (!F) {
2908       // If value is an alias, need to get the aliased base object to
2909       // see if it is a function.
2910       auto *GA = dyn_cast<GlobalAlias>(Name.getValue());
2911       if (GA && GA->getBaseObject())
2912         F = dyn_cast<Function>(GA->getBaseObject());
2913     }
2914 
2915     // VST_CODE_ENTRY:   [valueid, namechar x N]
2916     // VST_CODE_FNENTRY: [valueid, funcoffset, namechar x N]
2917     // VST_CODE_BBENTRY: [bbid, namechar x N]
2918     unsigned Code;
2919     if (isa<BasicBlock>(Name.getValue())) {
2920       Code = bitc::VST_CODE_BBENTRY;
2921       if (Bits == SE_Char6)
2922         AbbrevToUse = VST_BBENTRY_6_ABBREV;
2923     } else if (F && !F->isDeclaration()) {
2924       // Must be the module-level VST, where we pass in the Index and
2925       // have a VSTOffsetPlaceholder. The function-level VST should not
2926       // contain any Function symbols.
2927       assert(FunctionToBitcodeIndex);
2928       assert(hasVSTOffsetPlaceholder());
2929 
2930       // Save the word offset of the function (from the start of the
2931       // actual bitcode written to the stream).
2932       uint64_t BitcodeIndex = (*FunctionToBitcodeIndex)[F] - bitcodeStartBit();
2933       assert((BitcodeIndex & 31) == 0 && "function block not 32-bit aligned");
2934       // Note that we add 1 here because the offset is relative to one word
2935       // before the start of the identification block, which was historically
2936       // always the start of the regular bitcode header.
2937       NameVals.push_back(BitcodeIndex / 32 + 1);
2938 
2939       Code = bitc::VST_CODE_FNENTRY;
2940       AbbrevToUse = FnEntry8BitAbbrev;
2941       if (Bits == SE_Char6)
2942         AbbrevToUse = FnEntry6BitAbbrev;
2943       else if (Bits == SE_Fixed7)
2944         AbbrevToUse = FnEntry7BitAbbrev;
2945     } else {
2946       Code = bitc::VST_CODE_ENTRY;
2947       if (Bits == SE_Char6)
2948         AbbrevToUse = VST_ENTRY_6_ABBREV;
2949       else if (Bits == SE_Fixed7)
2950         AbbrevToUse = VST_ENTRY_7_ABBREV;
2951     }
2952 
2953     for (const auto P : Name.getKey())
2954       NameVals.push_back((unsigned char)P);
2955 
2956     // Emit the finished record.
2957     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
2958     NameVals.clear();
2959   }
2960   // Emit any GUID valueIDs created for indirect call edges into the
2961   // module-level VST.
2962   if (IsModuleLevel && hasVSTOffsetPlaceholder())
2963     for (const auto &GI : valueIds()) {
2964       NameVals.push_back(GI.second);
2965       NameVals.push_back(GI.first);
2966       Stream.EmitRecord(bitc::VST_CODE_COMBINED_ENTRY, NameVals,
2967                         GUIDEntryAbbrev);
2968       NameVals.clear();
2969     }
2970   Stream.ExitBlock();
2971 }
2972 
2973 /// Emit function names and summary offsets for the combined index
2974 /// used by ThinLTO.
2975 void IndexBitcodeWriter::writeCombinedValueSymbolTable() {
2976   assert(hasVSTOffsetPlaceholder() && "Expected non-zero VSTOffsetPlaceholder");
2977   // Get the offset of the VST we are writing, and backpatch it into
2978   // the VST forward declaration record.
2979   uint64_t VSTOffset = Stream.GetCurrentBitNo();
2980   assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
2981   Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32);
2982 
2983   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
2984 
2985   auto Abbv = std::make_shared<BitCodeAbbrev>();
2986   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_COMBINED_ENTRY));
2987   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
2988   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // refguid
2989   unsigned EntryAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2990 
2991   SmallVector<uint64_t, 64> NameVals;
2992   for (const auto &GVI : valueIds()) {
2993     // VST_CODE_COMBINED_ENTRY: [valueid, refguid]
2994     NameVals.push_back(GVI.second);
2995     NameVals.push_back(GVI.first);
2996 
2997     // Emit the finished record.
2998     Stream.EmitRecord(bitc::VST_CODE_COMBINED_ENTRY, NameVals, EntryAbbrev);
2999     NameVals.clear();
3000   }
3001   Stream.ExitBlock();
3002 }
3003 
3004 void ModuleBitcodeWriter::writeUseList(UseListOrder &&Order) {
3005   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
3006   unsigned Code;
3007   if (isa<BasicBlock>(Order.V))
3008     Code = bitc::USELIST_CODE_BB;
3009   else
3010     Code = bitc::USELIST_CODE_DEFAULT;
3011 
3012   SmallVector<uint64_t, 64> Record(Order.Shuffle.begin(), Order.Shuffle.end());
3013   Record.push_back(VE.getValueID(Order.V));
3014   Stream.EmitRecord(Code, Record);
3015 }
3016 
3017 void ModuleBitcodeWriter::writeUseListBlock(const Function *F) {
3018   assert(VE.shouldPreserveUseListOrder() &&
3019          "Expected to be preserving use-list order");
3020 
3021   auto hasMore = [&]() {
3022     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
3023   };
3024   if (!hasMore())
3025     // Nothing to do.
3026     return;
3027 
3028   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
3029   while (hasMore()) {
3030     writeUseList(std::move(VE.UseListOrders.back()));
3031     VE.UseListOrders.pop_back();
3032   }
3033   Stream.ExitBlock();
3034 }
3035 
3036 /// Emit a function body to the module stream.
3037 void ModuleBitcodeWriter::writeFunction(
3038     const Function &F,
3039     DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3040   // Save the bitcode index of the start of this function block for recording
3041   // in the VST.
3042   FunctionToBitcodeIndex[&F] = Stream.GetCurrentBitNo();
3043 
3044   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
3045   VE.incorporateFunction(F);
3046 
3047   SmallVector<unsigned, 64> Vals;
3048 
3049   // Emit the number of basic blocks, so the reader can create them ahead of
3050   // time.
3051   Vals.push_back(VE.getBasicBlocks().size());
3052   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
3053   Vals.clear();
3054 
3055   // If there are function-local constants, emit them now.
3056   unsigned CstStart, CstEnd;
3057   VE.getFunctionConstantRange(CstStart, CstEnd);
3058   writeConstants(CstStart, CstEnd, false);
3059 
3060   // If there is function-local metadata, emit it now.
3061   writeFunctionMetadata(F);
3062 
3063   // Keep a running idea of what the instruction ID is.
3064   unsigned InstID = CstEnd;
3065 
3066   bool NeedsMetadataAttachment = F.hasMetadata();
3067 
3068   DILocation *LastDL = nullptr;
3069   // Finally, emit all the instructions, in order.
3070   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
3071     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
3072          I != E; ++I) {
3073       writeInstruction(*I, InstID, Vals);
3074 
3075       if (!I->getType()->isVoidTy())
3076         ++InstID;
3077 
3078       // If the instruction has metadata, write a metadata attachment later.
3079       NeedsMetadataAttachment |= I->hasMetadataOtherThanDebugLoc();
3080 
3081       // If the instruction has a debug location, emit it.
3082       DILocation *DL = I->getDebugLoc();
3083       if (!DL)
3084         continue;
3085 
3086       if (DL == LastDL) {
3087         // Just repeat the same debug loc as last time.
3088         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
3089         continue;
3090       }
3091 
3092       Vals.push_back(DL->getLine());
3093       Vals.push_back(DL->getColumn());
3094       Vals.push_back(VE.getMetadataOrNullID(DL->getScope()));
3095       Vals.push_back(VE.getMetadataOrNullID(DL->getInlinedAt()));
3096       Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
3097       Vals.clear();
3098 
3099       LastDL = DL;
3100     }
3101 
3102   // Emit names for all the instructions etc.
3103   if (auto *Symtab = F.getValueSymbolTable())
3104     writeValueSymbolTable(*Symtab);
3105 
3106   if (NeedsMetadataAttachment)
3107     writeFunctionMetadataAttachment(F);
3108   if (VE.shouldPreserveUseListOrder())
3109     writeUseListBlock(&F);
3110   VE.purgeFunction();
3111   Stream.ExitBlock();
3112 }
3113 
3114 // Emit blockinfo, which defines the standard abbreviations etc.
3115 void ModuleBitcodeWriter::writeBlockInfo() {
3116   // We only want to emit block info records for blocks that have multiple
3117   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
3118   // Other blocks can define their abbrevs inline.
3119   Stream.EnterBlockInfoBlock();
3120 
3121   { // 8-bit fixed-width VST_CODE_ENTRY/VST_CODE_BBENTRY strings.
3122     auto Abbv = std::make_shared<BitCodeAbbrev>();
3123     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
3124     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3125     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3126     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3127     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3128         VST_ENTRY_8_ABBREV)
3129       llvm_unreachable("Unexpected abbrev ordering!");
3130   }
3131 
3132   { // 7-bit fixed width VST_CODE_ENTRY strings.
3133     auto Abbv = std::make_shared<BitCodeAbbrev>();
3134     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3135     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3136     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3137     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3138     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3139         VST_ENTRY_7_ABBREV)
3140       llvm_unreachable("Unexpected abbrev ordering!");
3141   }
3142   { // 6-bit char6 VST_CODE_ENTRY strings.
3143     auto Abbv = std::make_shared<BitCodeAbbrev>();
3144     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3145     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3146     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3147     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3148     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3149         VST_ENTRY_6_ABBREV)
3150       llvm_unreachable("Unexpected abbrev ordering!");
3151   }
3152   { // 6-bit char6 VST_CODE_BBENTRY strings.
3153     auto Abbv = std::make_shared<BitCodeAbbrev>();
3154     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
3155     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3156     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3157     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3158     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3159         VST_BBENTRY_6_ABBREV)
3160       llvm_unreachable("Unexpected abbrev ordering!");
3161   }
3162 
3163 
3164 
3165   { // SETTYPE abbrev for CONSTANTS_BLOCK.
3166     auto Abbv = std::make_shared<BitCodeAbbrev>();
3167     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
3168     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
3169                               VE.computeBitsRequiredForTypeIndicies()));
3170     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3171         CONSTANTS_SETTYPE_ABBREV)
3172       llvm_unreachable("Unexpected abbrev ordering!");
3173   }
3174 
3175   { // INTEGER abbrev for CONSTANTS_BLOCK.
3176     auto Abbv = std::make_shared<BitCodeAbbrev>();
3177     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
3178     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3179     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3180         CONSTANTS_INTEGER_ABBREV)
3181       llvm_unreachable("Unexpected abbrev ordering!");
3182   }
3183 
3184   { // CE_CAST abbrev for CONSTANTS_BLOCK.
3185     auto Abbv = std::make_shared<BitCodeAbbrev>();
3186     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
3187     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
3188     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
3189                               VE.computeBitsRequiredForTypeIndicies()));
3190     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
3191 
3192     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3193         CONSTANTS_CE_CAST_Abbrev)
3194       llvm_unreachable("Unexpected abbrev ordering!");
3195   }
3196   { // NULL abbrev for CONSTANTS_BLOCK.
3197     auto Abbv = std::make_shared<BitCodeAbbrev>();
3198     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
3199     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3200         CONSTANTS_NULL_Abbrev)
3201       llvm_unreachable("Unexpected abbrev ordering!");
3202   }
3203 
3204   // FIXME: This should only use space for first class types!
3205 
3206   { // INST_LOAD abbrev for FUNCTION_BLOCK.
3207     auto Abbv = std::make_shared<BitCodeAbbrev>();
3208     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
3209     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
3210     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
3211                               VE.computeBitsRequiredForTypeIndicies()));
3212     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
3213     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
3214     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3215         FUNCTION_INST_LOAD_ABBREV)
3216       llvm_unreachable("Unexpected abbrev ordering!");
3217   }
3218   { // INST_BINOP abbrev for FUNCTION_BLOCK.
3219     auto Abbv = std::make_shared<BitCodeAbbrev>();
3220     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3221     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3222     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3223     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3224     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3225         FUNCTION_INST_BINOP_ABBREV)
3226       llvm_unreachable("Unexpected abbrev ordering!");
3227   }
3228   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
3229     auto Abbv = std::make_shared<BitCodeAbbrev>();
3230     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3231     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3232     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3233     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3234     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7)); // flags
3235     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3236         FUNCTION_INST_BINOP_FLAGS_ABBREV)
3237       llvm_unreachable("Unexpected abbrev ordering!");
3238   }
3239   { // INST_CAST abbrev for FUNCTION_BLOCK.
3240     auto Abbv = std::make_shared<BitCodeAbbrev>();
3241     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
3242     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
3243     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
3244                               VE.computeBitsRequiredForTypeIndicies()));
3245     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
3246     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3247         FUNCTION_INST_CAST_ABBREV)
3248       llvm_unreachable("Unexpected abbrev ordering!");
3249   }
3250 
3251   { // INST_RET abbrev for FUNCTION_BLOCK.
3252     auto Abbv = std::make_shared<BitCodeAbbrev>();
3253     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3254     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3255         FUNCTION_INST_RET_VOID_ABBREV)
3256       llvm_unreachable("Unexpected abbrev ordering!");
3257   }
3258   { // INST_RET abbrev for FUNCTION_BLOCK.
3259     auto Abbv = std::make_shared<BitCodeAbbrev>();
3260     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3261     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
3262     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3263         FUNCTION_INST_RET_VAL_ABBREV)
3264       llvm_unreachable("Unexpected abbrev ordering!");
3265   }
3266   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
3267     auto Abbv = std::make_shared<BitCodeAbbrev>();
3268     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
3269     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3270         FUNCTION_INST_UNREACHABLE_ABBREV)
3271       llvm_unreachable("Unexpected abbrev ordering!");
3272   }
3273   {
3274     auto Abbv = std::make_shared<BitCodeAbbrev>();
3275     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_GEP));
3276     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
3277     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, // dest ty
3278                               Log2_32_Ceil(VE.getTypes().size() + 1)));
3279     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3280     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
3281     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3282         FUNCTION_INST_GEP_ABBREV)
3283       llvm_unreachable("Unexpected abbrev ordering!");
3284   }
3285 
3286   Stream.ExitBlock();
3287 }
3288 
3289 /// Write the module path strings, currently only used when generating
3290 /// a combined index file.
3291 void IndexBitcodeWriter::writeModStrings() {
3292   Stream.EnterSubblock(bitc::MODULE_STRTAB_BLOCK_ID, 3);
3293 
3294   // TODO: See which abbrev sizes we actually need to emit
3295 
3296   // 8-bit fixed-width MST_ENTRY strings.
3297   auto Abbv = std::make_shared<BitCodeAbbrev>();
3298   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3299   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3300   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3301   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3302   unsigned Abbrev8Bit = Stream.EmitAbbrev(std::move(Abbv));
3303 
3304   // 7-bit fixed width MST_ENTRY strings.
3305   Abbv = std::make_shared<BitCodeAbbrev>();
3306   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3307   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3308   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3309   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3310   unsigned Abbrev7Bit = Stream.EmitAbbrev(std::move(Abbv));
3311 
3312   // 6-bit char6 MST_ENTRY strings.
3313   Abbv = std::make_shared<BitCodeAbbrev>();
3314   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3315   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3316   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3317   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3318   unsigned Abbrev6Bit = Stream.EmitAbbrev(std::move(Abbv));
3319 
3320   // Module Hash, 160 bits SHA1. Optionally, emitted after each MST_CODE_ENTRY.
3321   Abbv = std::make_shared<BitCodeAbbrev>();
3322   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_HASH));
3323   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3324   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3325   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3326   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3327   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3328   unsigned AbbrevHash = Stream.EmitAbbrev(std::move(Abbv));
3329 
3330   SmallVector<unsigned, 64> Vals;
3331   for (const auto &MPSE : Index.modulePaths()) {
3332     if (!doIncludeModule(MPSE.getKey()))
3333       continue;
3334     StringEncoding Bits =
3335         getStringEncoding(MPSE.getKey().data(), MPSE.getKey().size());
3336     unsigned AbbrevToUse = Abbrev8Bit;
3337     if (Bits == SE_Char6)
3338       AbbrevToUse = Abbrev6Bit;
3339     else if (Bits == SE_Fixed7)
3340       AbbrevToUse = Abbrev7Bit;
3341 
3342     Vals.push_back(MPSE.getValue().first);
3343 
3344     for (const auto P : MPSE.getKey())
3345       Vals.push_back((unsigned char)P);
3346 
3347     // Emit the finished record.
3348     Stream.EmitRecord(bitc::MST_CODE_ENTRY, Vals, AbbrevToUse);
3349 
3350     Vals.clear();
3351     // Emit an optional hash for the module now
3352     auto &Hash = MPSE.getValue().second;
3353     bool AllZero = true; // Detect if the hash is empty, and do not generate it
3354     for (auto Val : Hash) {
3355       if (Val)
3356         AllZero = false;
3357       Vals.push_back(Val);
3358     }
3359     if (!AllZero) {
3360       // Emit the hash record.
3361       Stream.EmitRecord(bitc::MST_CODE_HASH, Vals, AbbrevHash);
3362     }
3363 
3364     Vals.clear();
3365   }
3366   Stream.ExitBlock();
3367 }
3368 
3369 // Helper to emit a single function summary record.
3370 void ModuleBitcodeWriter::writePerModuleFunctionSummaryRecord(
3371     SmallVector<uint64_t, 64> &NameVals, GlobalValueSummary *Summary,
3372     unsigned ValueID, unsigned FSCallsAbbrev, unsigned FSCallsProfileAbbrev,
3373     const Function &F) {
3374   NameVals.push_back(ValueID);
3375 
3376   FunctionSummary *FS = cast<FunctionSummary>(Summary);
3377   if (!FS->type_tests().empty())
3378     Stream.EmitRecord(bitc::FS_TYPE_TESTS, FS->type_tests());
3379 
3380   NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
3381   NameVals.push_back(FS->instCount());
3382   NameVals.push_back(FS->refs().size());
3383 
3384   for (auto &RI : FS->refs())
3385     NameVals.push_back(VE.getValueID(RI.getValue()));
3386 
3387   bool HasProfileData = F.getEntryCount().hasValue();
3388   for (auto &ECI : FS->calls()) {
3389     NameVals.push_back(getValueId(ECI.first));
3390     if (HasProfileData)
3391       NameVals.push_back(static_cast<uint8_t>(ECI.second.Hotness));
3392   }
3393 
3394   unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
3395   unsigned Code =
3396       (HasProfileData ? bitc::FS_PERMODULE_PROFILE : bitc::FS_PERMODULE);
3397 
3398   // Emit the finished record.
3399   Stream.EmitRecord(Code, NameVals, FSAbbrev);
3400   NameVals.clear();
3401 }
3402 
3403 // Collect the global value references in the given variable's initializer,
3404 // and emit them in a summary record.
3405 void ModuleBitcodeWriter::writeModuleLevelReferences(
3406     const GlobalVariable &V, SmallVector<uint64_t, 64> &NameVals,
3407     unsigned FSModRefsAbbrev) {
3408   auto Summaries =
3409       Index->findGlobalValueSummaryList(GlobalValue::getGUID(V.getName()));
3410   if (Summaries == Index->end()) {
3411     // Only declarations should not have a summary (a declaration might however
3412     // have a summary if the def was in module level asm).
3413     assert(V.isDeclaration());
3414     return;
3415   }
3416   auto *Summary = Summaries->second.front().get();
3417   NameVals.push_back(VE.getValueID(&V));
3418   GlobalVarSummary *VS = cast<GlobalVarSummary>(Summary);
3419   NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
3420 
3421   unsigned SizeBeforeRefs = NameVals.size();
3422   for (auto &RI : VS->refs())
3423     NameVals.push_back(VE.getValueID(RI.getValue()));
3424   // Sort the refs for determinism output, the vector returned by FS->refs() has
3425   // been initialized from a DenseSet.
3426   std::sort(NameVals.begin() + SizeBeforeRefs, NameVals.end());
3427 
3428   Stream.EmitRecord(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS, NameVals,
3429                     FSModRefsAbbrev);
3430   NameVals.clear();
3431 }
3432 
3433 // Current version for the summary.
3434 // This is bumped whenever we introduce changes in the way some record are
3435 // interpreted, like flags for instance.
3436 static const uint64_t INDEX_VERSION = 3;
3437 
3438 /// Emit the per-module summary section alongside the rest of
3439 /// the module's bitcode.
3440 void ModuleBitcodeWriter::writePerModuleGlobalValueSummary() {
3441   Stream.EnterSubblock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID, 4);
3442 
3443   Stream.EmitRecord(bitc::FS_VERSION, ArrayRef<uint64_t>{INDEX_VERSION});
3444 
3445   if (Index->begin() == Index->end()) {
3446     Stream.ExitBlock();
3447     return;
3448   }
3449 
3450   // Abbrev for FS_PERMODULE.
3451   auto Abbv = std::make_shared<BitCodeAbbrev>();
3452   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE));
3453   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3454   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3455   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3456   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3457   // numrefs x valueid, n x (valueid)
3458   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3459   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3460   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3461 
3462   // Abbrev for FS_PERMODULE_PROFILE.
3463   Abbv = std::make_shared<BitCodeAbbrev>();
3464   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_PROFILE));
3465   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3466   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3467   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3468   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3469   // numrefs x valueid, n x (valueid, hotness)
3470   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3471   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3472   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3473 
3474   // Abbrev for FS_PERMODULE_GLOBALVAR_INIT_REFS.
3475   Abbv = std::make_shared<BitCodeAbbrev>();
3476   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS));
3477   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
3478   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
3479   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));  // valueids
3480   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3481   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3482 
3483   // Abbrev for FS_ALIAS.
3484   Abbv = std::make_shared<BitCodeAbbrev>();
3485   Abbv->Add(BitCodeAbbrevOp(bitc::FS_ALIAS));
3486   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3487   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3488   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3489   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3490 
3491   SmallVector<uint64_t, 64> NameVals;
3492   // Iterate over the list of functions instead of the Index to
3493   // ensure the ordering is stable.
3494   for (const Function &F : M) {
3495     // Summary emission does not support anonymous functions, they have to
3496     // renamed using the anonymous function renaming pass.
3497     if (!F.hasName())
3498       report_fatal_error("Unexpected anonymous function when writing summary");
3499 
3500     auto Summaries =
3501         Index->findGlobalValueSummaryList(GlobalValue::getGUID(F.getName()));
3502     if (Summaries == Index->end()) {
3503       // Only declarations should not have a summary (a declaration might
3504       // however have a summary if the def was in module level asm).
3505       assert(F.isDeclaration());
3506       continue;
3507     }
3508     auto *Summary = Summaries->second.front().get();
3509     writePerModuleFunctionSummaryRecord(NameVals, Summary, VE.getValueID(&F),
3510                                         FSCallsAbbrev, FSCallsProfileAbbrev, F);
3511   }
3512 
3513   // Capture references from GlobalVariable initializers, which are outside
3514   // of a function scope.
3515   for (const GlobalVariable &G : M.globals())
3516     writeModuleLevelReferences(G, NameVals, FSModRefsAbbrev);
3517 
3518   for (const GlobalAlias &A : M.aliases()) {
3519     auto *Aliasee = A.getBaseObject();
3520     if (!Aliasee->hasName())
3521       // Nameless function don't have an entry in the summary, skip it.
3522       continue;
3523     auto AliasId = VE.getValueID(&A);
3524     auto AliaseeId = VE.getValueID(Aliasee);
3525     NameVals.push_back(AliasId);
3526     auto *Summary = Index->getGlobalValueSummary(A);
3527     AliasSummary *AS = cast<AliasSummary>(Summary);
3528     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
3529     NameVals.push_back(AliaseeId);
3530     Stream.EmitRecord(bitc::FS_ALIAS, NameVals, FSAliasAbbrev);
3531     NameVals.clear();
3532   }
3533 
3534   Stream.ExitBlock();
3535 }
3536 
3537 /// Emit the combined summary section into the combined index file.
3538 void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
3539   Stream.EnterSubblock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID, 3);
3540   Stream.EmitRecord(bitc::FS_VERSION, ArrayRef<uint64_t>{INDEX_VERSION});
3541 
3542   // Abbrev for FS_COMBINED.
3543   auto Abbv = std::make_shared<BitCodeAbbrev>();
3544   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED));
3545   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3546   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3547   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3548   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3549   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3550   // numrefs x valueid, n x (valueid)
3551   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3552   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3553   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3554 
3555   // Abbrev for FS_COMBINED_PROFILE.
3556   Abbv = std::make_shared<BitCodeAbbrev>();
3557   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_PROFILE));
3558   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3559   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3560   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3561   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3562   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3563   // numrefs x valueid, n x (valueid, hotness)
3564   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3565   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3566   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3567 
3568   // Abbrev for FS_COMBINED_GLOBALVAR_INIT_REFS.
3569   Abbv = std::make_shared<BitCodeAbbrev>();
3570   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS));
3571   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3572   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3573   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3574   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));    // valueids
3575   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3576   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3577 
3578   // Abbrev for FS_COMBINED_ALIAS.
3579   Abbv = std::make_shared<BitCodeAbbrev>();
3580   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_ALIAS));
3581   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3582   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3583   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3584   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3585   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3586 
3587   // The aliases are emitted as a post-pass, and will point to the value
3588   // id of the aliasee. Save them in a vector for post-processing.
3589   SmallVector<AliasSummary *, 64> Aliases;
3590 
3591   // Save the value id for each summary for alias emission.
3592   DenseMap<const GlobalValueSummary *, unsigned> SummaryToValueIdMap;
3593 
3594   SmallVector<uint64_t, 64> NameVals;
3595 
3596   // For local linkage, we also emit the original name separately
3597   // immediately after the record.
3598   auto MaybeEmitOriginalName = [&](GlobalValueSummary &S) {
3599     if (!GlobalValue::isLocalLinkage(S.linkage()))
3600       return;
3601     NameVals.push_back(S.getOriginalName());
3602     Stream.EmitRecord(bitc::FS_COMBINED_ORIGINAL_NAME, NameVals);
3603     NameVals.clear();
3604   };
3605 
3606   for (const auto &I : *this) {
3607     GlobalValueSummary *S = I.second;
3608     assert(S);
3609 
3610     assert(hasValueId(I.first));
3611     unsigned ValueId = getValueId(I.first);
3612     SummaryToValueIdMap[S] = ValueId;
3613 
3614     if (auto *AS = dyn_cast<AliasSummary>(S)) {
3615       // Will process aliases as a post-pass because the reader wants all
3616       // global to be loaded first.
3617       Aliases.push_back(AS);
3618       continue;
3619     }
3620 
3621     if (auto *VS = dyn_cast<GlobalVarSummary>(S)) {
3622       NameVals.push_back(ValueId);
3623       NameVals.push_back(Index.getModuleId(VS->modulePath()));
3624       NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
3625       for (auto &RI : VS->refs()) {
3626         NameVals.push_back(getValueId(RI.getGUID()));
3627       }
3628 
3629       // Emit the finished record.
3630       Stream.EmitRecord(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS, NameVals,
3631                         FSModRefsAbbrev);
3632       NameVals.clear();
3633       MaybeEmitOriginalName(*S);
3634       continue;
3635     }
3636 
3637     auto *FS = cast<FunctionSummary>(S);
3638     if (!FS->type_tests().empty())
3639       Stream.EmitRecord(bitc::FS_TYPE_TESTS, FS->type_tests());
3640 
3641     NameVals.push_back(ValueId);
3642     NameVals.push_back(Index.getModuleId(FS->modulePath()));
3643     NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
3644     NameVals.push_back(FS->instCount());
3645     NameVals.push_back(FS->refs().size());
3646 
3647     for (auto &RI : FS->refs()) {
3648       NameVals.push_back(getValueId(RI.getGUID()));
3649     }
3650 
3651     bool HasProfileData = false;
3652     for (auto &EI : FS->calls()) {
3653       HasProfileData |= EI.second.Hotness != CalleeInfo::HotnessType::Unknown;
3654       if (HasProfileData)
3655         break;
3656     }
3657 
3658     for (auto &EI : FS->calls()) {
3659       // If this GUID doesn't have a value id, it doesn't have a function
3660       // summary and we don't need to record any calls to it.
3661       if (!hasValueId(EI.first.getGUID()))
3662         continue;
3663       NameVals.push_back(getValueId(EI.first.getGUID()));
3664       if (HasProfileData)
3665         NameVals.push_back(static_cast<uint8_t>(EI.second.Hotness));
3666     }
3667 
3668     unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
3669     unsigned Code =
3670         (HasProfileData ? bitc::FS_COMBINED_PROFILE : bitc::FS_COMBINED);
3671 
3672     // Emit the finished record.
3673     Stream.EmitRecord(Code, NameVals, FSAbbrev);
3674     NameVals.clear();
3675     MaybeEmitOriginalName(*S);
3676   }
3677 
3678   for (auto *AS : Aliases) {
3679     auto AliasValueId = SummaryToValueIdMap[AS];
3680     assert(AliasValueId);
3681     NameVals.push_back(AliasValueId);
3682     NameVals.push_back(Index.getModuleId(AS->modulePath()));
3683     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
3684     auto AliaseeValueId = SummaryToValueIdMap[&AS->getAliasee()];
3685     assert(AliaseeValueId);
3686     NameVals.push_back(AliaseeValueId);
3687 
3688     // Emit the finished record.
3689     Stream.EmitRecord(bitc::FS_COMBINED_ALIAS, NameVals, FSAliasAbbrev);
3690     NameVals.clear();
3691     MaybeEmitOriginalName(*AS);
3692   }
3693 
3694   Stream.ExitBlock();
3695 }
3696 
3697 /// Create the "IDENTIFICATION_BLOCK_ID" containing a single string with the
3698 /// current llvm version, and a record for the epoch number.
3699 void writeIdentificationBlock(BitstreamWriter &Stream) {
3700   Stream.EnterSubblock(bitc::IDENTIFICATION_BLOCK_ID, 5);
3701 
3702   // Write the "user readable" string identifying the bitcode producer
3703   auto Abbv = std::make_shared<BitCodeAbbrev>();
3704   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_STRING));
3705   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3706   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3707   auto StringAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3708   writeStringRecord(Stream, bitc::IDENTIFICATION_CODE_STRING,
3709                     "LLVM" LLVM_VERSION_STRING, StringAbbrev);
3710 
3711   // Write the epoch version
3712   Abbv = std::make_shared<BitCodeAbbrev>();
3713   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_EPOCH));
3714   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
3715   auto EpochAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3716   SmallVector<unsigned, 1> Vals = {bitc::BITCODE_CURRENT_EPOCH};
3717   Stream.EmitRecord(bitc::IDENTIFICATION_CODE_EPOCH, Vals, EpochAbbrev);
3718   Stream.ExitBlock();
3719 }
3720 
3721 void ModuleBitcodeWriter::writeModuleHash(size_t BlockStartPos) {
3722   // Emit the module's hash.
3723   // MODULE_CODE_HASH: [5*i32]
3724   SHA1 Hasher;
3725   Hasher.update(ArrayRef<uint8_t>((const uint8_t *)&(Buffer)[BlockStartPos],
3726                                   Buffer.size() - BlockStartPos));
3727   StringRef Hash = Hasher.result();
3728   uint32_t Vals[5];
3729   for (int Pos = 0; Pos < 20; Pos += 4) {
3730     Vals[Pos / 4] = support::endian::read32be(Hash.data() + Pos);
3731   }
3732 
3733   // Emit the finished record.
3734   Stream.EmitRecord(bitc::MODULE_CODE_HASH, Vals);
3735 }
3736 
3737 void ModuleBitcodeWriter::write() {
3738   writeIdentificationBlock(Stream);
3739 
3740   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
3741   size_t BlockStartPos = Buffer.size();
3742 
3743   SmallVector<unsigned, 1> Vals;
3744   unsigned CurVersion = 1;
3745   Vals.push_back(CurVersion);
3746   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
3747 
3748   // Emit blockinfo, which defines the standard abbreviations etc.
3749   writeBlockInfo();
3750 
3751   // Emit information about attribute groups.
3752   writeAttributeGroupTable();
3753 
3754   // Emit information about parameter attributes.
3755   writeAttributeTable();
3756 
3757   // Emit information describing all of the types in the module.
3758   writeTypeTable();
3759 
3760   writeComdats();
3761 
3762   // Emit top-level description of module, including target triple, inline asm,
3763   // descriptors for global variables, and function prototype info.
3764   writeModuleInfo();
3765 
3766   // Emit constants.
3767   writeModuleConstants();
3768 
3769   // Emit metadata kind names.
3770   writeModuleMetadataKinds();
3771 
3772   // Emit metadata.
3773   writeModuleMetadata();
3774 
3775   // Emit module-level use-lists.
3776   if (VE.shouldPreserveUseListOrder())
3777     writeUseListBlock(nullptr);
3778 
3779   writeOperandBundleTags();
3780 
3781   // Emit function bodies.
3782   DenseMap<const Function *, uint64_t> FunctionToBitcodeIndex;
3783   for (Module::const_iterator F = M.begin(), E = M.end(); F != E; ++F)
3784     if (!F->isDeclaration())
3785       writeFunction(*F, FunctionToBitcodeIndex);
3786 
3787   // Need to write after the above call to WriteFunction which populates
3788   // the summary information in the index.
3789   if (Index)
3790     writePerModuleGlobalValueSummary();
3791 
3792   writeValueSymbolTable(M.getValueSymbolTable(),
3793                         /* IsModuleLevel */ true, &FunctionToBitcodeIndex);
3794 
3795   if (GenerateHash) {
3796     writeModuleHash(BlockStartPos);
3797   }
3798 
3799   Stream.ExitBlock();
3800 }
3801 
3802 static void writeInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
3803                                uint32_t &Position) {
3804   support::endian::write32le(&Buffer[Position], Value);
3805   Position += 4;
3806 }
3807 
3808 /// If generating a bc file on darwin, we have to emit a
3809 /// header and trailer to make it compatible with the system archiver.  To do
3810 /// this we emit the following header, and then emit a trailer that pads the
3811 /// file out to be a multiple of 16 bytes.
3812 ///
3813 /// struct bc_header {
3814 ///   uint32_t Magic;         // 0x0B17C0DE
3815 ///   uint32_t Version;       // Version, currently always 0.
3816 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
3817 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
3818 ///   uint32_t CPUType;       // CPU specifier.
3819 ///   ... potentially more later ...
3820 /// };
3821 static void emitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
3822                                          const Triple &TT) {
3823   unsigned CPUType = ~0U;
3824 
3825   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
3826   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
3827   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
3828   // specific constants here because they are implicitly part of the Darwin ABI.
3829   enum {
3830     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
3831     DARWIN_CPU_TYPE_X86        = 7,
3832     DARWIN_CPU_TYPE_ARM        = 12,
3833     DARWIN_CPU_TYPE_POWERPC    = 18
3834   };
3835 
3836   Triple::ArchType Arch = TT.getArch();
3837   if (Arch == Triple::x86_64)
3838     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
3839   else if (Arch == Triple::x86)
3840     CPUType = DARWIN_CPU_TYPE_X86;
3841   else if (Arch == Triple::ppc)
3842     CPUType = DARWIN_CPU_TYPE_POWERPC;
3843   else if (Arch == Triple::ppc64)
3844     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
3845   else if (Arch == Triple::arm || Arch == Triple::thumb)
3846     CPUType = DARWIN_CPU_TYPE_ARM;
3847 
3848   // Traditional Bitcode starts after header.
3849   assert(Buffer.size() >= BWH_HeaderSize &&
3850          "Expected header size to be reserved");
3851   unsigned BCOffset = BWH_HeaderSize;
3852   unsigned BCSize = Buffer.size() - BWH_HeaderSize;
3853 
3854   // Write the magic and version.
3855   unsigned Position = 0;
3856   writeInt32ToBuffer(0x0B17C0DE, Buffer, Position);
3857   writeInt32ToBuffer(0, Buffer, Position); // Version.
3858   writeInt32ToBuffer(BCOffset, Buffer, Position);
3859   writeInt32ToBuffer(BCSize, Buffer, Position);
3860   writeInt32ToBuffer(CPUType, Buffer, Position);
3861 
3862   // If the file is not a multiple of 16 bytes, insert dummy padding.
3863   while (Buffer.size() & 15)
3864     Buffer.push_back(0);
3865 }
3866 
3867 /// Helper to write the header common to all bitcode files.
3868 static void writeBitcodeHeader(BitstreamWriter &Stream) {
3869   // Emit the file header.
3870   Stream.Emit((unsigned)'B', 8);
3871   Stream.Emit((unsigned)'C', 8);
3872   Stream.Emit(0x0, 4);
3873   Stream.Emit(0xC, 4);
3874   Stream.Emit(0xE, 4);
3875   Stream.Emit(0xD, 4);
3876 }
3877 
3878 BitcodeWriter::BitcodeWriter(SmallVectorImpl<char> &Buffer)
3879     : Buffer(Buffer), Stream(new BitstreamWriter(Buffer)) {
3880   writeBitcodeHeader(*Stream);
3881 }
3882 
3883 BitcodeWriter::~BitcodeWriter() = default;
3884 
3885 void BitcodeWriter::writeModule(const Module *M,
3886                                 bool ShouldPreserveUseListOrder,
3887                                 const ModuleSummaryIndex *Index,
3888                                 bool GenerateHash) {
3889   ModuleBitcodeWriter ModuleWriter(
3890       M, Buffer, *Stream, ShouldPreserveUseListOrder, Index, GenerateHash);
3891   ModuleWriter.write();
3892 }
3893 
3894 /// WriteBitcodeToFile - Write the specified module to the specified output
3895 /// stream.
3896 void llvm::WriteBitcodeToFile(const Module *M, raw_ostream &Out,
3897                               bool ShouldPreserveUseListOrder,
3898                               const ModuleSummaryIndex *Index,
3899                               bool GenerateHash) {
3900   SmallVector<char, 0> Buffer;
3901   Buffer.reserve(256*1024);
3902 
3903   // If this is darwin or another generic macho target, reserve space for the
3904   // header.
3905   Triple TT(M->getTargetTriple());
3906   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
3907     Buffer.insert(Buffer.begin(), BWH_HeaderSize, 0);
3908 
3909   BitcodeWriter Writer(Buffer);
3910   Writer.writeModule(M, ShouldPreserveUseListOrder, Index, GenerateHash);
3911 
3912   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
3913     emitDarwinBCHeaderAndTrailer(Buffer, TT);
3914 
3915   // Write the generated bitstream to "Out".
3916   Out.write((char*)&Buffer.front(), Buffer.size());
3917 }
3918 
3919 void IndexBitcodeWriter::write() {
3920   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
3921 
3922   SmallVector<unsigned, 1> Vals;
3923   unsigned CurVersion = 1;
3924   Vals.push_back(CurVersion);
3925   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, Vals);
3926 
3927   // If we have a VST, write the VSTOFFSET record placeholder.
3928   writeValueSymbolTableForwardDecl();
3929 
3930   // Write the module paths in the combined index.
3931   writeModStrings();
3932 
3933   // Write the summary combined index records.
3934   writeCombinedGlobalValueSummary();
3935 
3936   // Need a special VST writer for the combined index (we don't have a
3937   // real VST and real values when this is invoked).
3938   writeCombinedValueSymbolTable();
3939 
3940   Stream.ExitBlock();
3941 }
3942 
3943 // Write the specified module summary index to the given raw output stream,
3944 // where it will be written in a new bitcode block. This is used when
3945 // writing the combined index file for ThinLTO. When writing a subset of the
3946 // index for a distributed backend, provide a \p ModuleToSummariesForIndex map.
3947 void llvm::WriteIndexToFile(
3948     const ModuleSummaryIndex &Index, raw_ostream &Out,
3949     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
3950   SmallVector<char, 0> Buffer;
3951   Buffer.reserve(256 * 1024);
3952 
3953   BitstreamWriter Stream(Buffer);
3954   writeBitcodeHeader(Stream);
3955 
3956   IndexBitcodeWriter IndexWriter(Stream, Index, ModuleToSummariesForIndex);
3957   IndexWriter.write();
3958 
3959   Out.write((char *)&Buffer.front(), Buffer.size());
3960 }
3961