1 //===- Bitcode/Writer/BitcodeWriter.cpp - Bitcode Writer ------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // Bitcode writer implementation.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "llvm/Bitcode/BitcodeWriter.h"
14 #include "ValueEnumerator.h"
15 #include "llvm/ADT/APFloat.h"
16 #include "llvm/ADT/APInt.h"
17 #include "llvm/ADT/ArrayRef.h"
18 #include "llvm/ADT/DenseMap.h"
19 #include "llvm/ADT/None.h"
20 #include "llvm/ADT/Optional.h"
21 #include "llvm/ADT/STLExtras.h"
22 #include "llvm/ADT/SmallString.h"
23 #include "llvm/ADT/SmallVector.h"
24 #include "llvm/ADT/StringMap.h"
25 #include "llvm/ADT/StringRef.h"
26 #include "llvm/ADT/Triple.h"
27 #include "llvm/Bitcode/BitcodeCommon.h"
28 #include "llvm/Bitcode/BitcodeReader.h"
29 #include "llvm/Bitcode/LLVMBitCodes.h"
30 #include "llvm/Bitstream/BitCodes.h"
31 #include "llvm/Bitstream/BitstreamWriter.h"
32 #include "llvm/Config/llvm-config.h"
33 #include "llvm/IR/Attributes.h"
34 #include "llvm/IR/BasicBlock.h"
35 #include "llvm/IR/Comdat.h"
36 #include "llvm/IR/Constant.h"
37 #include "llvm/IR/Constants.h"
38 #include "llvm/IR/DebugInfoMetadata.h"
39 #include "llvm/IR/DebugLoc.h"
40 #include "llvm/IR/DerivedTypes.h"
41 #include "llvm/IR/Function.h"
42 #include "llvm/IR/GlobalAlias.h"
43 #include "llvm/IR/GlobalIFunc.h"
44 #include "llvm/IR/GlobalObject.h"
45 #include "llvm/IR/GlobalValue.h"
46 #include "llvm/IR/GlobalVariable.h"
47 #include "llvm/IR/InlineAsm.h"
48 #include "llvm/IR/InstrTypes.h"
49 #include "llvm/IR/Instruction.h"
50 #include "llvm/IR/Instructions.h"
51 #include "llvm/IR/LLVMContext.h"
52 #include "llvm/IR/Metadata.h"
53 #include "llvm/IR/Module.h"
54 #include "llvm/IR/ModuleSummaryIndex.h"
55 #include "llvm/IR/Operator.h"
56 #include "llvm/IR/Type.h"
57 #include "llvm/IR/UseListOrder.h"
58 #include "llvm/IR/Value.h"
59 #include "llvm/IR/ValueSymbolTable.h"
60 #include "llvm/MC/StringTableBuilder.h"
61 #include "llvm/Object/IRSymtab.h"
62 #include "llvm/Support/AtomicOrdering.h"
63 #include "llvm/Support/Casting.h"
64 #include "llvm/Support/CommandLine.h"
65 #include "llvm/Support/Endian.h"
66 #include "llvm/Support/Error.h"
67 #include "llvm/Support/ErrorHandling.h"
68 #include "llvm/Support/MathExtras.h"
69 #include "llvm/Support/SHA1.h"
70 #include "llvm/Support/TargetRegistry.h"
71 #include "llvm/Support/raw_ostream.h"
72 #include <algorithm>
73 #include <cassert>
74 #include <cstddef>
75 #include <cstdint>
76 #include <iterator>
77 #include <map>
78 #include <memory>
79 #include <string>
80 #include <utility>
81 #include <vector>
82 
83 using namespace llvm;
84 
85 static cl::opt<unsigned>
86     IndexThreshold("bitcode-mdindex-threshold", cl::Hidden, cl::init(25),
87                    cl::desc("Number of metadatas above which we emit an index "
88                             "to enable lazy-loading"));
89 static cl::opt<uint32_t> FlushThreshold(
90     "bitcode-flush-threshold", cl::Hidden, cl::init(512),
91     cl::desc("The threshold (unit M) for flushing LLVM bitcode."));
92 
93 static cl::opt<bool> WriteRelBFToSummary(
94     "write-relbf-to-summary", cl::Hidden, cl::init(false),
95     cl::desc("Write relative block frequency to function summary "));
96 
97 extern FunctionSummary::ForceSummaryHotnessType ForceSummaryEdgesCold;
98 
99 namespace {
100 
101 /// These are manifest constants used by the bitcode writer. They do not need to
102 /// be kept in sync with the reader, but need to be consistent within this file.
103 enum {
104   // VALUE_SYMTAB_BLOCK abbrev id's.
105   VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
106   VST_ENTRY_7_ABBREV,
107   VST_ENTRY_6_ABBREV,
108   VST_BBENTRY_6_ABBREV,
109 
110   // CONSTANTS_BLOCK abbrev id's.
111   CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
112   CONSTANTS_INTEGER_ABBREV,
113   CONSTANTS_CE_CAST_Abbrev,
114   CONSTANTS_NULL_Abbrev,
115 
116   // FUNCTION_BLOCK abbrev id's.
117   FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
118   FUNCTION_INST_UNOP_ABBREV,
119   FUNCTION_INST_UNOP_FLAGS_ABBREV,
120   FUNCTION_INST_BINOP_ABBREV,
121   FUNCTION_INST_BINOP_FLAGS_ABBREV,
122   FUNCTION_INST_CAST_ABBREV,
123   FUNCTION_INST_RET_VOID_ABBREV,
124   FUNCTION_INST_RET_VAL_ABBREV,
125   FUNCTION_INST_UNREACHABLE_ABBREV,
126   FUNCTION_INST_GEP_ABBREV,
127 };
128 
129 /// Abstract class to manage the bitcode writing, subclassed for each bitcode
130 /// file type.
131 class BitcodeWriterBase {
132 protected:
133   /// The stream created and owned by the client.
134   BitstreamWriter &Stream;
135 
136   StringTableBuilder &StrtabBuilder;
137 
138 public:
139   /// Constructs a BitcodeWriterBase object that writes to the provided
140   /// \p Stream.
141   BitcodeWriterBase(BitstreamWriter &Stream, StringTableBuilder &StrtabBuilder)
142       : Stream(Stream), StrtabBuilder(StrtabBuilder) {}
143 
144 protected:
145   void writeBitcodeHeader();
146   void writeModuleVersion();
147 };
148 
149 void BitcodeWriterBase::writeModuleVersion() {
150   // VERSION: [version#]
151   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, ArrayRef<uint64_t>{2});
152 }
153 
154 /// Base class to manage the module bitcode writing, currently subclassed for
155 /// ModuleBitcodeWriter and ThinLinkBitcodeWriter.
156 class ModuleBitcodeWriterBase : public BitcodeWriterBase {
157 protected:
158   /// The Module to write to bitcode.
159   const Module &M;
160 
161   /// Enumerates ids for all values in the module.
162   ValueEnumerator VE;
163 
164   /// Optional per-module index to write for ThinLTO.
165   const ModuleSummaryIndex *Index;
166 
167   /// Map that holds the correspondence between GUIDs in the summary index,
168   /// that came from indirect call profiles, and a value id generated by this
169   /// class to use in the VST and summary block records.
170   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
171 
172   /// Tracks the last value id recorded in the GUIDToValueMap.
173   unsigned GlobalValueId;
174 
175   /// Saves the offset of the VSTOffset record that must eventually be
176   /// backpatched with the offset of the actual VST.
177   uint64_t VSTOffsetPlaceholder = 0;
178 
179 public:
180   /// Constructs a ModuleBitcodeWriterBase object for the given Module,
181   /// writing to the provided \p Buffer.
182   ModuleBitcodeWriterBase(const Module &M, StringTableBuilder &StrtabBuilder,
183                           BitstreamWriter &Stream,
184                           bool ShouldPreserveUseListOrder,
185                           const ModuleSummaryIndex *Index)
186       : BitcodeWriterBase(Stream, StrtabBuilder), M(M),
187         VE(M, ShouldPreserveUseListOrder), Index(Index) {
188     // Assign ValueIds to any callee values in the index that came from
189     // indirect call profiles and were recorded as a GUID not a Value*
190     // (which would have been assigned an ID by the ValueEnumerator).
191     // The starting ValueId is just after the number of values in the
192     // ValueEnumerator, so that they can be emitted in the VST.
193     GlobalValueId = VE.getValues().size();
194     if (!Index)
195       return;
196     for (const auto &GUIDSummaryLists : *Index)
197       // Examine all summaries for this GUID.
198       for (auto &Summary : GUIDSummaryLists.second.SummaryList)
199         if (auto FS = dyn_cast<FunctionSummary>(Summary.get()))
200           // For each call in the function summary, see if the call
201           // is to a GUID (which means it is for an indirect call,
202           // otherwise we would have a Value for it). If so, synthesize
203           // a value id.
204           for (auto &CallEdge : FS->calls())
205             if (!CallEdge.first.haveGVs() || !CallEdge.first.getValue())
206               assignValueId(CallEdge.first.getGUID());
207   }
208 
209 protected:
210   void writePerModuleGlobalValueSummary();
211 
212 private:
213   void writePerModuleFunctionSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
214                                            GlobalValueSummary *Summary,
215                                            unsigned ValueID,
216                                            unsigned FSCallsAbbrev,
217                                            unsigned FSCallsProfileAbbrev,
218                                            const Function &F);
219   void writeModuleLevelReferences(const GlobalVariable &V,
220                                   SmallVector<uint64_t, 64> &NameVals,
221                                   unsigned FSModRefsAbbrev,
222                                   unsigned FSModVTableRefsAbbrev);
223 
224   void assignValueId(GlobalValue::GUID ValGUID) {
225     GUIDToValueIdMap[ValGUID] = ++GlobalValueId;
226   }
227 
228   unsigned getValueId(GlobalValue::GUID ValGUID) {
229     const auto &VMI = GUIDToValueIdMap.find(ValGUID);
230     // Expect that any GUID value had a value Id assigned by an
231     // earlier call to assignValueId.
232     assert(VMI != GUIDToValueIdMap.end() &&
233            "GUID does not have assigned value Id");
234     return VMI->second;
235   }
236 
237   // Helper to get the valueId for the type of value recorded in VI.
238   unsigned getValueId(ValueInfo VI) {
239     if (!VI.haveGVs() || !VI.getValue())
240       return getValueId(VI.getGUID());
241     return VE.getValueID(VI.getValue());
242   }
243 
244   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
245 };
246 
247 /// Class to manage the bitcode writing for a module.
248 class ModuleBitcodeWriter : public ModuleBitcodeWriterBase {
249   /// Pointer to the buffer allocated by caller for bitcode writing.
250   const SmallVectorImpl<char> &Buffer;
251 
252   /// True if a module hash record should be written.
253   bool GenerateHash;
254 
255   /// If non-null, when GenerateHash is true, the resulting hash is written
256   /// into ModHash.
257   ModuleHash *ModHash;
258 
259   SHA1 Hasher;
260 
261   /// The start bit of the identification block.
262   uint64_t BitcodeStartBit;
263 
264 public:
265   /// Constructs a ModuleBitcodeWriter object for the given Module,
266   /// writing to the provided \p Buffer.
267   ModuleBitcodeWriter(const Module &M, SmallVectorImpl<char> &Buffer,
268                       StringTableBuilder &StrtabBuilder,
269                       BitstreamWriter &Stream, bool ShouldPreserveUseListOrder,
270                       const ModuleSummaryIndex *Index, bool GenerateHash,
271                       ModuleHash *ModHash = nullptr)
272       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
273                                 ShouldPreserveUseListOrder, Index),
274         Buffer(Buffer), GenerateHash(GenerateHash), ModHash(ModHash),
275         BitcodeStartBit(Stream.GetCurrentBitNo()) {}
276 
277   /// Emit the current module to the bitstream.
278   void write();
279 
280 private:
281   uint64_t bitcodeStartBit() { return BitcodeStartBit; }
282 
283   size_t addToStrtab(StringRef Str);
284 
285   void writeAttributeGroupTable();
286   void writeAttributeTable();
287   void writeTypeTable();
288   void writeComdats();
289   void writeValueSymbolTableForwardDecl();
290   void writeModuleInfo();
291   void writeValueAsMetadata(const ValueAsMetadata *MD,
292                             SmallVectorImpl<uint64_t> &Record);
293   void writeMDTuple(const MDTuple *N, SmallVectorImpl<uint64_t> &Record,
294                     unsigned Abbrev);
295   unsigned createDILocationAbbrev();
296   void writeDILocation(const DILocation *N, SmallVectorImpl<uint64_t> &Record,
297                        unsigned &Abbrev);
298   unsigned createGenericDINodeAbbrev();
299   void writeGenericDINode(const GenericDINode *N,
300                           SmallVectorImpl<uint64_t> &Record, unsigned &Abbrev);
301   void writeDISubrange(const DISubrange *N, SmallVectorImpl<uint64_t> &Record,
302                        unsigned Abbrev);
303   void writeDIGenericSubrange(const DIGenericSubrange *N,
304                               SmallVectorImpl<uint64_t> &Record,
305                               unsigned Abbrev);
306   void writeDIEnumerator(const DIEnumerator *N,
307                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
308   void writeDIBasicType(const DIBasicType *N, SmallVectorImpl<uint64_t> &Record,
309                         unsigned Abbrev);
310   void writeDIStringType(const DIStringType *N,
311                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
312   void writeDIDerivedType(const DIDerivedType *N,
313                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
314   void writeDICompositeType(const DICompositeType *N,
315                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
316   void writeDISubroutineType(const DISubroutineType *N,
317                              SmallVectorImpl<uint64_t> &Record,
318                              unsigned Abbrev);
319   void writeDIFile(const DIFile *N, SmallVectorImpl<uint64_t> &Record,
320                    unsigned Abbrev);
321   void writeDICompileUnit(const DICompileUnit *N,
322                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
323   void writeDISubprogram(const DISubprogram *N,
324                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
325   void writeDILexicalBlock(const DILexicalBlock *N,
326                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
327   void writeDILexicalBlockFile(const DILexicalBlockFile *N,
328                                SmallVectorImpl<uint64_t> &Record,
329                                unsigned Abbrev);
330   void writeDICommonBlock(const DICommonBlock *N,
331                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
332   void writeDINamespace(const DINamespace *N, SmallVectorImpl<uint64_t> &Record,
333                         unsigned Abbrev);
334   void writeDIMacro(const DIMacro *N, SmallVectorImpl<uint64_t> &Record,
335                     unsigned Abbrev);
336   void writeDIMacroFile(const DIMacroFile *N, SmallVectorImpl<uint64_t> &Record,
337                         unsigned Abbrev);
338   void writeDIModule(const DIModule *N, SmallVectorImpl<uint64_t> &Record,
339                      unsigned Abbrev);
340   void writeDITemplateTypeParameter(const DITemplateTypeParameter *N,
341                                     SmallVectorImpl<uint64_t> &Record,
342                                     unsigned Abbrev);
343   void writeDITemplateValueParameter(const DITemplateValueParameter *N,
344                                      SmallVectorImpl<uint64_t> &Record,
345                                      unsigned Abbrev);
346   void writeDIGlobalVariable(const DIGlobalVariable *N,
347                              SmallVectorImpl<uint64_t> &Record,
348                              unsigned Abbrev);
349   void writeDILocalVariable(const DILocalVariable *N,
350                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
351   void writeDILabel(const DILabel *N,
352                     SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
353   void writeDIExpression(const DIExpression *N,
354                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
355   void writeDIGlobalVariableExpression(const DIGlobalVariableExpression *N,
356                                        SmallVectorImpl<uint64_t> &Record,
357                                        unsigned Abbrev);
358   void writeDIObjCProperty(const DIObjCProperty *N,
359                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
360   void writeDIImportedEntity(const DIImportedEntity *N,
361                              SmallVectorImpl<uint64_t> &Record,
362                              unsigned Abbrev);
363   unsigned createNamedMetadataAbbrev();
364   void writeNamedMetadata(SmallVectorImpl<uint64_t> &Record);
365   unsigned createMetadataStringsAbbrev();
366   void writeMetadataStrings(ArrayRef<const Metadata *> Strings,
367                             SmallVectorImpl<uint64_t> &Record);
368   void writeMetadataRecords(ArrayRef<const Metadata *> MDs,
369                             SmallVectorImpl<uint64_t> &Record,
370                             std::vector<unsigned> *MDAbbrevs = nullptr,
371                             std::vector<uint64_t> *IndexPos = nullptr);
372   void writeModuleMetadata();
373   void writeFunctionMetadata(const Function &F);
374   void writeFunctionMetadataAttachment(const Function &F);
375   void writeGlobalVariableMetadataAttachment(const GlobalVariable &GV);
376   void pushGlobalMetadataAttachment(SmallVectorImpl<uint64_t> &Record,
377                                     const GlobalObject &GO);
378   void writeModuleMetadataKinds();
379   void writeOperandBundleTags();
380   void writeSyncScopeNames();
381   void writeConstants(unsigned FirstVal, unsigned LastVal, bool isGlobal);
382   void writeModuleConstants();
383   bool pushValueAndType(const Value *V, unsigned InstID,
384                         SmallVectorImpl<unsigned> &Vals);
385   void writeOperandBundles(const CallBase &CB, unsigned InstID);
386   void pushValue(const Value *V, unsigned InstID,
387                  SmallVectorImpl<unsigned> &Vals);
388   void pushValueSigned(const Value *V, unsigned InstID,
389                        SmallVectorImpl<uint64_t> &Vals);
390   void writeInstruction(const Instruction &I, unsigned InstID,
391                         SmallVectorImpl<unsigned> &Vals);
392   void writeFunctionLevelValueSymbolTable(const ValueSymbolTable &VST);
393   void writeGlobalValueSymbolTable(
394       DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
395   void writeUseList(UseListOrder &&Order);
396   void writeUseListBlock(const Function *F);
397   void
398   writeFunction(const Function &F,
399                 DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
400   void writeBlockInfo();
401   void writeModuleHash(size_t BlockStartPos);
402 
403   unsigned getEncodedSyncScopeID(SyncScope::ID SSID) {
404     return unsigned(SSID);
405   }
406 
407   unsigned getEncodedAlign(MaybeAlign Alignment) { return encode(Alignment); }
408 };
409 
410 /// Class to manage the bitcode writing for a combined index.
411 class IndexBitcodeWriter : public BitcodeWriterBase {
412   /// The combined index to write to bitcode.
413   const ModuleSummaryIndex &Index;
414 
415   /// When writing a subset of the index for distributed backends, client
416   /// provides a map of modules to the corresponding GUIDs/summaries to write.
417   const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex;
418 
419   /// Map that holds the correspondence between the GUID used in the combined
420   /// index and a value id generated by this class to use in references.
421   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
422 
423   /// Tracks the last value id recorded in the GUIDToValueMap.
424   unsigned GlobalValueId = 0;
425 
426 public:
427   /// Constructs a IndexBitcodeWriter object for the given combined index,
428   /// writing to the provided \p Buffer. When writing a subset of the index
429   /// for a distributed backend, provide a \p ModuleToSummariesForIndex map.
430   IndexBitcodeWriter(BitstreamWriter &Stream, StringTableBuilder &StrtabBuilder,
431                      const ModuleSummaryIndex &Index,
432                      const std::map<std::string, GVSummaryMapTy>
433                          *ModuleToSummariesForIndex = nullptr)
434       : BitcodeWriterBase(Stream, StrtabBuilder), Index(Index),
435         ModuleToSummariesForIndex(ModuleToSummariesForIndex) {
436     // Assign unique value ids to all summaries to be written, for use
437     // in writing out the call graph edges. Save the mapping from GUID
438     // to the new global value id to use when writing those edges, which
439     // are currently saved in the index in terms of GUID.
440     forEachSummary([&](GVInfo I, bool) {
441       GUIDToValueIdMap[I.first] = ++GlobalValueId;
442     });
443   }
444 
445   /// The below iterator returns the GUID and associated summary.
446   using GVInfo = std::pair<GlobalValue::GUID, GlobalValueSummary *>;
447 
448   /// Calls the callback for each value GUID and summary to be written to
449   /// bitcode. This hides the details of whether they are being pulled from the
450   /// entire index or just those in a provided ModuleToSummariesForIndex map.
451   template<typename Functor>
452   void forEachSummary(Functor Callback) {
453     if (ModuleToSummariesForIndex) {
454       for (auto &M : *ModuleToSummariesForIndex)
455         for (auto &Summary : M.second) {
456           Callback(Summary, false);
457           // Ensure aliasee is handled, e.g. for assigning a valueId,
458           // even if we are not importing the aliasee directly (the
459           // imported alias will contain a copy of aliasee).
460           if (auto *AS = dyn_cast<AliasSummary>(Summary.getSecond()))
461             Callback({AS->getAliaseeGUID(), &AS->getAliasee()}, true);
462         }
463     } else {
464       for (auto &Summaries : Index)
465         for (auto &Summary : Summaries.second.SummaryList)
466           Callback({Summaries.first, Summary.get()}, false);
467     }
468   }
469 
470   /// Calls the callback for each entry in the modulePaths StringMap that
471   /// should be written to the module path string table. This hides the details
472   /// of whether they are being pulled from the entire index or just those in a
473   /// provided ModuleToSummariesForIndex map.
474   template <typename Functor> void forEachModule(Functor Callback) {
475     if (ModuleToSummariesForIndex) {
476       for (const auto &M : *ModuleToSummariesForIndex) {
477         const auto &MPI = Index.modulePaths().find(M.first);
478         if (MPI == Index.modulePaths().end()) {
479           // This should only happen if the bitcode file was empty, in which
480           // case we shouldn't be importing (the ModuleToSummariesForIndex
481           // would only include the module we are writing and index for).
482           assert(ModuleToSummariesForIndex->size() == 1);
483           continue;
484         }
485         Callback(*MPI);
486       }
487     } else {
488       for (const auto &MPSE : Index.modulePaths())
489         Callback(MPSE);
490     }
491   }
492 
493   /// Main entry point for writing a combined index to bitcode.
494   void write();
495 
496 private:
497   void writeModStrings();
498   void writeCombinedGlobalValueSummary();
499 
500   Optional<unsigned> getValueId(GlobalValue::GUID ValGUID) {
501     auto VMI = GUIDToValueIdMap.find(ValGUID);
502     if (VMI == GUIDToValueIdMap.end())
503       return None;
504     return VMI->second;
505   }
506 
507   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
508 };
509 
510 } // end anonymous namespace
511 
512 static unsigned getEncodedCastOpcode(unsigned Opcode) {
513   switch (Opcode) {
514   default: llvm_unreachable("Unknown cast instruction!");
515   case Instruction::Trunc   : return bitc::CAST_TRUNC;
516   case Instruction::ZExt    : return bitc::CAST_ZEXT;
517   case Instruction::SExt    : return bitc::CAST_SEXT;
518   case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
519   case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
520   case Instruction::UIToFP  : return bitc::CAST_UITOFP;
521   case Instruction::SIToFP  : return bitc::CAST_SITOFP;
522   case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
523   case Instruction::FPExt   : return bitc::CAST_FPEXT;
524   case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
525   case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
526   case Instruction::BitCast : return bitc::CAST_BITCAST;
527   case Instruction::AddrSpaceCast: return bitc::CAST_ADDRSPACECAST;
528   }
529 }
530 
531 static unsigned getEncodedUnaryOpcode(unsigned Opcode) {
532   switch (Opcode) {
533   default: llvm_unreachable("Unknown binary instruction!");
534   case Instruction::FNeg: return bitc::UNOP_FNEG;
535   }
536 }
537 
538 static unsigned getEncodedBinaryOpcode(unsigned Opcode) {
539   switch (Opcode) {
540   default: llvm_unreachable("Unknown binary instruction!");
541   case Instruction::Add:
542   case Instruction::FAdd: return bitc::BINOP_ADD;
543   case Instruction::Sub:
544   case Instruction::FSub: return bitc::BINOP_SUB;
545   case Instruction::Mul:
546   case Instruction::FMul: return bitc::BINOP_MUL;
547   case Instruction::UDiv: return bitc::BINOP_UDIV;
548   case Instruction::FDiv:
549   case Instruction::SDiv: return bitc::BINOP_SDIV;
550   case Instruction::URem: return bitc::BINOP_UREM;
551   case Instruction::FRem:
552   case Instruction::SRem: return bitc::BINOP_SREM;
553   case Instruction::Shl:  return bitc::BINOP_SHL;
554   case Instruction::LShr: return bitc::BINOP_LSHR;
555   case Instruction::AShr: return bitc::BINOP_ASHR;
556   case Instruction::And:  return bitc::BINOP_AND;
557   case Instruction::Or:   return bitc::BINOP_OR;
558   case Instruction::Xor:  return bitc::BINOP_XOR;
559   }
560 }
561 
562 static unsigned getEncodedRMWOperation(AtomicRMWInst::BinOp Op) {
563   switch (Op) {
564   default: llvm_unreachable("Unknown RMW operation!");
565   case AtomicRMWInst::Xchg: return bitc::RMW_XCHG;
566   case AtomicRMWInst::Add: return bitc::RMW_ADD;
567   case AtomicRMWInst::Sub: return bitc::RMW_SUB;
568   case AtomicRMWInst::And: return bitc::RMW_AND;
569   case AtomicRMWInst::Nand: return bitc::RMW_NAND;
570   case AtomicRMWInst::Or: return bitc::RMW_OR;
571   case AtomicRMWInst::Xor: return bitc::RMW_XOR;
572   case AtomicRMWInst::Max: return bitc::RMW_MAX;
573   case AtomicRMWInst::Min: return bitc::RMW_MIN;
574   case AtomicRMWInst::UMax: return bitc::RMW_UMAX;
575   case AtomicRMWInst::UMin: return bitc::RMW_UMIN;
576   case AtomicRMWInst::FAdd: return bitc::RMW_FADD;
577   case AtomicRMWInst::FSub: return bitc::RMW_FSUB;
578   }
579 }
580 
581 static unsigned getEncodedOrdering(AtomicOrdering Ordering) {
582   switch (Ordering) {
583   case AtomicOrdering::NotAtomic: return bitc::ORDERING_NOTATOMIC;
584   case AtomicOrdering::Unordered: return bitc::ORDERING_UNORDERED;
585   case AtomicOrdering::Monotonic: return bitc::ORDERING_MONOTONIC;
586   case AtomicOrdering::Acquire: return bitc::ORDERING_ACQUIRE;
587   case AtomicOrdering::Release: return bitc::ORDERING_RELEASE;
588   case AtomicOrdering::AcquireRelease: return bitc::ORDERING_ACQREL;
589   case AtomicOrdering::SequentiallyConsistent: return bitc::ORDERING_SEQCST;
590   }
591   llvm_unreachable("Invalid ordering");
592 }
593 
594 static void writeStringRecord(BitstreamWriter &Stream, unsigned Code,
595                               StringRef Str, unsigned AbbrevToUse) {
596   SmallVector<unsigned, 64> Vals;
597 
598   // Code: [strchar x N]
599   for (unsigned i = 0, e = Str.size(); i != e; ++i) {
600     if (AbbrevToUse && !BitCodeAbbrevOp::isChar6(Str[i]))
601       AbbrevToUse = 0;
602     Vals.push_back(Str[i]);
603   }
604 
605   // Emit the finished record.
606   Stream.EmitRecord(Code, Vals, AbbrevToUse);
607 }
608 
609 static uint64_t getAttrKindEncoding(Attribute::AttrKind Kind) {
610   switch (Kind) {
611   case Attribute::Alignment:
612     return bitc::ATTR_KIND_ALIGNMENT;
613   case Attribute::AllocSize:
614     return bitc::ATTR_KIND_ALLOC_SIZE;
615   case Attribute::AlwaysInline:
616     return bitc::ATTR_KIND_ALWAYS_INLINE;
617   case Attribute::ArgMemOnly:
618     return bitc::ATTR_KIND_ARGMEMONLY;
619   case Attribute::Builtin:
620     return bitc::ATTR_KIND_BUILTIN;
621   case Attribute::ByVal:
622     return bitc::ATTR_KIND_BY_VAL;
623   case Attribute::Convergent:
624     return bitc::ATTR_KIND_CONVERGENT;
625   case Attribute::InAlloca:
626     return bitc::ATTR_KIND_IN_ALLOCA;
627   case Attribute::Cold:
628     return bitc::ATTR_KIND_COLD;
629   case Attribute::Hot:
630     return bitc::ATTR_KIND_HOT;
631   case Attribute::InaccessibleMemOnly:
632     return bitc::ATTR_KIND_INACCESSIBLEMEM_ONLY;
633   case Attribute::InaccessibleMemOrArgMemOnly:
634     return bitc::ATTR_KIND_INACCESSIBLEMEM_OR_ARGMEMONLY;
635   case Attribute::InlineHint:
636     return bitc::ATTR_KIND_INLINE_HINT;
637   case Attribute::InReg:
638     return bitc::ATTR_KIND_IN_REG;
639   case Attribute::JumpTable:
640     return bitc::ATTR_KIND_JUMP_TABLE;
641   case Attribute::MinSize:
642     return bitc::ATTR_KIND_MIN_SIZE;
643   case Attribute::Naked:
644     return bitc::ATTR_KIND_NAKED;
645   case Attribute::Nest:
646     return bitc::ATTR_KIND_NEST;
647   case Attribute::NoAlias:
648     return bitc::ATTR_KIND_NO_ALIAS;
649   case Attribute::NoBuiltin:
650     return bitc::ATTR_KIND_NO_BUILTIN;
651   case Attribute::NoCallback:
652     return bitc::ATTR_KIND_NO_CALLBACK;
653   case Attribute::NoCapture:
654     return bitc::ATTR_KIND_NO_CAPTURE;
655   case Attribute::NoDuplicate:
656     return bitc::ATTR_KIND_NO_DUPLICATE;
657   case Attribute::NoFree:
658     return bitc::ATTR_KIND_NOFREE;
659   case Attribute::NoImplicitFloat:
660     return bitc::ATTR_KIND_NO_IMPLICIT_FLOAT;
661   case Attribute::NoInline:
662     return bitc::ATTR_KIND_NO_INLINE;
663   case Attribute::NoRecurse:
664     return bitc::ATTR_KIND_NO_RECURSE;
665   case Attribute::NoMerge:
666     return bitc::ATTR_KIND_NO_MERGE;
667   case Attribute::NonLazyBind:
668     return bitc::ATTR_KIND_NON_LAZY_BIND;
669   case Attribute::NonNull:
670     return bitc::ATTR_KIND_NON_NULL;
671   case Attribute::Dereferenceable:
672     return bitc::ATTR_KIND_DEREFERENCEABLE;
673   case Attribute::DereferenceableOrNull:
674     return bitc::ATTR_KIND_DEREFERENCEABLE_OR_NULL;
675   case Attribute::NoRedZone:
676     return bitc::ATTR_KIND_NO_RED_ZONE;
677   case Attribute::NoReturn:
678     return bitc::ATTR_KIND_NO_RETURN;
679   case Attribute::NoSync:
680     return bitc::ATTR_KIND_NOSYNC;
681   case Attribute::NoCfCheck:
682     return bitc::ATTR_KIND_NOCF_CHECK;
683   case Attribute::NoProfile:
684     return bitc::ATTR_KIND_NO_PROFILE;
685   case Attribute::NoUnwind:
686     return bitc::ATTR_KIND_NO_UNWIND;
687   case Attribute::NullPointerIsValid:
688     return bitc::ATTR_KIND_NULL_POINTER_IS_VALID;
689   case Attribute::OptForFuzzing:
690     return bitc::ATTR_KIND_OPT_FOR_FUZZING;
691   case Attribute::OptimizeForSize:
692     return bitc::ATTR_KIND_OPTIMIZE_FOR_SIZE;
693   case Attribute::OptimizeNone:
694     return bitc::ATTR_KIND_OPTIMIZE_NONE;
695   case Attribute::ReadNone:
696     return bitc::ATTR_KIND_READ_NONE;
697   case Attribute::ReadOnly:
698     return bitc::ATTR_KIND_READ_ONLY;
699   case Attribute::Returned:
700     return bitc::ATTR_KIND_RETURNED;
701   case Attribute::ReturnsTwice:
702     return bitc::ATTR_KIND_RETURNS_TWICE;
703   case Attribute::SExt:
704     return bitc::ATTR_KIND_S_EXT;
705   case Attribute::Speculatable:
706     return bitc::ATTR_KIND_SPECULATABLE;
707   case Attribute::StackAlignment:
708     return bitc::ATTR_KIND_STACK_ALIGNMENT;
709   case Attribute::StackProtect:
710     return bitc::ATTR_KIND_STACK_PROTECT;
711   case Attribute::StackProtectReq:
712     return bitc::ATTR_KIND_STACK_PROTECT_REQ;
713   case Attribute::StackProtectStrong:
714     return bitc::ATTR_KIND_STACK_PROTECT_STRONG;
715   case Attribute::SafeStack:
716     return bitc::ATTR_KIND_SAFESTACK;
717   case Attribute::ShadowCallStack:
718     return bitc::ATTR_KIND_SHADOWCALLSTACK;
719   case Attribute::StrictFP:
720     return bitc::ATTR_KIND_STRICT_FP;
721   case Attribute::StructRet:
722     return bitc::ATTR_KIND_STRUCT_RET;
723   case Attribute::SanitizeAddress:
724     return bitc::ATTR_KIND_SANITIZE_ADDRESS;
725   case Attribute::SanitizeHWAddress:
726     return bitc::ATTR_KIND_SANITIZE_HWADDRESS;
727   case Attribute::SanitizeThread:
728     return bitc::ATTR_KIND_SANITIZE_THREAD;
729   case Attribute::SanitizeMemory:
730     return bitc::ATTR_KIND_SANITIZE_MEMORY;
731   case Attribute::SpeculativeLoadHardening:
732     return bitc::ATTR_KIND_SPECULATIVE_LOAD_HARDENING;
733   case Attribute::SwiftError:
734     return bitc::ATTR_KIND_SWIFT_ERROR;
735   case Attribute::SwiftSelf:
736     return bitc::ATTR_KIND_SWIFT_SELF;
737   case Attribute::UWTable:
738     return bitc::ATTR_KIND_UW_TABLE;
739   case Attribute::WillReturn:
740     return bitc::ATTR_KIND_WILLRETURN;
741   case Attribute::WriteOnly:
742     return bitc::ATTR_KIND_WRITEONLY;
743   case Attribute::ZExt:
744     return bitc::ATTR_KIND_Z_EXT;
745   case Attribute::ImmArg:
746     return bitc::ATTR_KIND_IMMARG;
747   case Attribute::SanitizeMemTag:
748     return bitc::ATTR_KIND_SANITIZE_MEMTAG;
749   case Attribute::Preallocated:
750     return bitc::ATTR_KIND_PREALLOCATED;
751   case Attribute::NoUndef:
752     return bitc::ATTR_KIND_NOUNDEF;
753   case Attribute::ByRef:
754     return bitc::ATTR_KIND_BYREF;
755   case Attribute::MustProgress:
756     return bitc::ATTR_KIND_MUSTPROGRESS;
757   case Attribute::EndAttrKinds:
758     llvm_unreachable("Can not encode end-attribute kinds marker.");
759   case Attribute::None:
760     llvm_unreachable("Can not encode none-attribute.");
761   case Attribute::EmptyKey:
762   case Attribute::TombstoneKey:
763     llvm_unreachable("Trying to encode EmptyKey/TombstoneKey");
764   }
765 
766   llvm_unreachable("Trying to encode unknown attribute");
767 }
768 
769 void ModuleBitcodeWriter::writeAttributeGroupTable() {
770   const std::vector<ValueEnumerator::IndexAndAttrSet> &AttrGrps =
771       VE.getAttributeGroups();
772   if (AttrGrps.empty()) return;
773 
774   Stream.EnterSubblock(bitc::PARAMATTR_GROUP_BLOCK_ID, 3);
775 
776   SmallVector<uint64_t, 64> Record;
777   for (ValueEnumerator::IndexAndAttrSet Pair : AttrGrps) {
778     unsigned AttrListIndex = Pair.first;
779     AttributeSet AS = Pair.second;
780     Record.push_back(VE.getAttributeGroupID(Pair));
781     Record.push_back(AttrListIndex);
782 
783     for (Attribute Attr : AS) {
784       if (Attr.isEnumAttribute()) {
785         Record.push_back(0);
786         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
787       } else if (Attr.isIntAttribute()) {
788         Record.push_back(1);
789         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
790         Record.push_back(Attr.getValueAsInt());
791       } else if (Attr.isStringAttribute()) {
792         StringRef Kind = Attr.getKindAsString();
793         StringRef Val = Attr.getValueAsString();
794 
795         Record.push_back(Val.empty() ? 3 : 4);
796         Record.append(Kind.begin(), Kind.end());
797         Record.push_back(0);
798         if (!Val.empty()) {
799           Record.append(Val.begin(), Val.end());
800           Record.push_back(0);
801         }
802       } else {
803         assert(Attr.isTypeAttribute());
804         Type *Ty = Attr.getValueAsType();
805         Record.push_back(Ty ? 6 : 5);
806         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
807         if (Ty)
808           Record.push_back(VE.getTypeID(Attr.getValueAsType()));
809       }
810     }
811 
812     Stream.EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
813     Record.clear();
814   }
815 
816   Stream.ExitBlock();
817 }
818 
819 void ModuleBitcodeWriter::writeAttributeTable() {
820   const std::vector<AttributeList> &Attrs = VE.getAttributeLists();
821   if (Attrs.empty()) return;
822 
823   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
824 
825   SmallVector<uint64_t, 64> Record;
826   for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
827     AttributeList AL = Attrs[i];
828     for (unsigned i = AL.index_begin(), e = AL.index_end(); i != e; ++i) {
829       AttributeSet AS = AL.getAttributes(i);
830       if (AS.hasAttributes())
831         Record.push_back(VE.getAttributeGroupID({i, AS}));
832     }
833 
834     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
835     Record.clear();
836   }
837 
838   Stream.ExitBlock();
839 }
840 
841 /// WriteTypeTable - Write out the type table for a module.
842 void ModuleBitcodeWriter::writeTypeTable() {
843   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
844 
845   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
846   SmallVector<uint64_t, 64> TypeVals;
847 
848   uint64_t NumBits = VE.computeBitsRequiredForTypeIndicies();
849 
850   // Abbrev for TYPE_CODE_POINTER.
851   auto Abbv = std::make_shared<BitCodeAbbrev>();
852   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
853   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
854   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
855   unsigned PtrAbbrev = Stream.EmitAbbrev(std::move(Abbv));
856 
857   // Abbrev for TYPE_CODE_FUNCTION.
858   Abbv = std::make_shared<BitCodeAbbrev>();
859   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
860   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
861   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
862   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
863   unsigned FunctionAbbrev = Stream.EmitAbbrev(std::move(Abbv));
864 
865   // Abbrev for TYPE_CODE_STRUCT_ANON.
866   Abbv = std::make_shared<BitCodeAbbrev>();
867   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
868   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
869   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
870   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
871   unsigned StructAnonAbbrev = Stream.EmitAbbrev(std::move(Abbv));
872 
873   // Abbrev for TYPE_CODE_STRUCT_NAME.
874   Abbv = std::make_shared<BitCodeAbbrev>();
875   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
876   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
877   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
878   unsigned StructNameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
879 
880   // Abbrev for TYPE_CODE_STRUCT_NAMED.
881   Abbv = std::make_shared<BitCodeAbbrev>();
882   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
883   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
884   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
885   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
886   unsigned StructNamedAbbrev = Stream.EmitAbbrev(std::move(Abbv));
887 
888   // Abbrev for TYPE_CODE_ARRAY.
889   Abbv = std::make_shared<BitCodeAbbrev>();
890   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
891   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
892   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
893   unsigned ArrayAbbrev = Stream.EmitAbbrev(std::move(Abbv));
894 
895   // Emit an entry count so the reader can reserve space.
896   TypeVals.push_back(TypeList.size());
897   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
898   TypeVals.clear();
899 
900   // Loop over all of the types, emitting each in turn.
901   for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
902     Type *T = TypeList[i];
903     int AbbrevToUse = 0;
904     unsigned Code = 0;
905 
906     switch (T->getTypeID()) {
907     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;      break;
908     case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;      break;
909     case Type::BFloatTyID:    Code = bitc::TYPE_CODE_BFLOAT;    break;
910     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;     break;
911     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE;    break;
912     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80;  break;
913     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128;     break;
914     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
915     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;     break;
916     case Type::MetadataTyID:  Code = bitc::TYPE_CODE_METADATA;  break;
917     case Type::X86_MMXTyID:   Code = bitc::TYPE_CODE_X86_MMX;   break;
918     case Type::X86_AMXTyID:   Code = bitc::TYPE_CODE_X86_AMX;   break;
919     case Type::TokenTyID:     Code = bitc::TYPE_CODE_TOKEN;     break;
920     case Type::IntegerTyID:
921       // INTEGER: [width]
922       Code = bitc::TYPE_CODE_INTEGER;
923       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
924       break;
925     case Type::PointerTyID: {
926       PointerType *PTy = cast<PointerType>(T);
927       // POINTER: [pointee type, address space]
928       Code = bitc::TYPE_CODE_POINTER;
929       TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
930       unsigned AddressSpace = PTy->getAddressSpace();
931       TypeVals.push_back(AddressSpace);
932       if (AddressSpace == 0) AbbrevToUse = PtrAbbrev;
933       break;
934     }
935     case Type::FunctionTyID: {
936       FunctionType *FT = cast<FunctionType>(T);
937       // FUNCTION: [isvararg, retty, paramty x N]
938       Code = bitc::TYPE_CODE_FUNCTION;
939       TypeVals.push_back(FT->isVarArg());
940       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
941       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
942         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
943       AbbrevToUse = FunctionAbbrev;
944       break;
945     }
946     case Type::StructTyID: {
947       StructType *ST = cast<StructType>(T);
948       // STRUCT: [ispacked, eltty x N]
949       TypeVals.push_back(ST->isPacked());
950       // Output all of the element types.
951       for (StructType::element_iterator I = ST->element_begin(),
952            E = ST->element_end(); I != E; ++I)
953         TypeVals.push_back(VE.getTypeID(*I));
954 
955       if (ST->isLiteral()) {
956         Code = bitc::TYPE_CODE_STRUCT_ANON;
957         AbbrevToUse = StructAnonAbbrev;
958       } else {
959         if (ST->isOpaque()) {
960           Code = bitc::TYPE_CODE_OPAQUE;
961         } else {
962           Code = bitc::TYPE_CODE_STRUCT_NAMED;
963           AbbrevToUse = StructNamedAbbrev;
964         }
965 
966         // Emit the name if it is present.
967         if (!ST->getName().empty())
968           writeStringRecord(Stream, bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
969                             StructNameAbbrev);
970       }
971       break;
972     }
973     case Type::ArrayTyID: {
974       ArrayType *AT = cast<ArrayType>(T);
975       // ARRAY: [numelts, eltty]
976       Code = bitc::TYPE_CODE_ARRAY;
977       TypeVals.push_back(AT->getNumElements());
978       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
979       AbbrevToUse = ArrayAbbrev;
980       break;
981     }
982     case Type::FixedVectorTyID:
983     case Type::ScalableVectorTyID: {
984       VectorType *VT = cast<VectorType>(T);
985       // VECTOR [numelts, eltty] or
986       //        [numelts, eltty, scalable]
987       Code = bitc::TYPE_CODE_VECTOR;
988       TypeVals.push_back(VT->getElementCount().getKnownMinValue());
989       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
990       if (isa<ScalableVectorType>(VT))
991         TypeVals.push_back(true);
992       break;
993     }
994     }
995 
996     // Emit the finished record.
997     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
998     TypeVals.clear();
999   }
1000 
1001   Stream.ExitBlock();
1002 }
1003 
1004 static unsigned getEncodedLinkage(const GlobalValue::LinkageTypes Linkage) {
1005   switch (Linkage) {
1006   case GlobalValue::ExternalLinkage:
1007     return 0;
1008   case GlobalValue::WeakAnyLinkage:
1009     return 16;
1010   case GlobalValue::AppendingLinkage:
1011     return 2;
1012   case GlobalValue::InternalLinkage:
1013     return 3;
1014   case GlobalValue::LinkOnceAnyLinkage:
1015     return 18;
1016   case GlobalValue::ExternalWeakLinkage:
1017     return 7;
1018   case GlobalValue::CommonLinkage:
1019     return 8;
1020   case GlobalValue::PrivateLinkage:
1021     return 9;
1022   case GlobalValue::WeakODRLinkage:
1023     return 17;
1024   case GlobalValue::LinkOnceODRLinkage:
1025     return 19;
1026   case GlobalValue::AvailableExternallyLinkage:
1027     return 12;
1028   }
1029   llvm_unreachable("Invalid linkage");
1030 }
1031 
1032 static unsigned getEncodedLinkage(const GlobalValue &GV) {
1033   return getEncodedLinkage(GV.getLinkage());
1034 }
1035 
1036 static uint64_t getEncodedFFlags(FunctionSummary::FFlags Flags) {
1037   uint64_t RawFlags = 0;
1038   RawFlags |= Flags.ReadNone;
1039   RawFlags |= (Flags.ReadOnly << 1);
1040   RawFlags |= (Flags.NoRecurse << 2);
1041   RawFlags |= (Flags.ReturnDoesNotAlias << 3);
1042   RawFlags |= (Flags.NoInline << 4);
1043   RawFlags |= (Flags.AlwaysInline << 5);
1044   return RawFlags;
1045 }
1046 
1047 // Decode the flags for GlobalValue in the summary
1048 static uint64_t getEncodedGVSummaryFlags(GlobalValueSummary::GVFlags Flags) {
1049   uint64_t RawFlags = 0;
1050 
1051   RawFlags |= Flags.NotEligibleToImport; // bool
1052   RawFlags |= (Flags.Live << 1);
1053   RawFlags |= (Flags.DSOLocal << 2);
1054   RawFlags |= (Flags.CanAutoHide << 3);
1055 
1056   // Linkage don't need to be remapped at that time for the summary. Any future
1057   // change to the getEncodedLinkage() function will need to be taken into
1058   // account here as well.
1059   RawFlags = (RawFlags << 4) | Flags.Linkage; // 4 bits
1060 
1061   return RawFlags;
1062 }
1063 
1064 static uint64_t getEncodedGVarFlags(GlobalVarSummary::GVarFlags Flags) {
1065   uint64_t RawFlags = Flags.MaybeReadOnly | (Flags.MaybeWriteOnly << 1) |
1066                       (Flags.Constant << 2) | Flags.VCallVisibility << 3;
1067   return RawFlags;
1068 }
1069 
1070 static unsigned getEncodedVisibility(const GlobalValue &GV) {
1071   switch (GV.getVisibility()) {
1072   case GlobalValue::DefaultVisibility:   return 0;
1073   case GlobalValue::HiddenVisibility:    return 1;
1074   case GlobalValue::ProtectedVisibility: return 2;
1075   }
1076   llvm_unreachable("Invalid visibility");
1077 }
1078 
1079 static unsigned getEncodedDLLStorageClass(const GlobalValue &GV) {
1080   switch (GV.getDLLStorageClass()) {
1081   case GlobalValue::DefaultStorageClass:   return 0;
1082   case GlobalValue::DLLImportStorageClass: return 1;
1083   case GlobalValue::DLLExportStorageClass: return 2;
1084   }
1085   llvm_unreachable("Invalid DLL storage class");
1086 }
1087 
1088 static unsigned getEncodedThreadLocalMode(const GlobalValue &GV) {
1089   switch (GV.getThreadLocalMode()) {
1090     case GlobalVariable::NotThreadLocal:         return 0;
1091     case GlobalVariable::GeneralDynamicTLSModel: return 1;
1092     case GlobalVariable::LocalDynamicTLSModel:   return 2;
1093     case GlobalVariable::InitialExecTLSModel:    return 3;
1094     case GlobalVariable::LocalExecTLSModel:      return 4;
1095   }
1096   llvm_unreachable("Invalid TLS model");
1097 }
1098 
1099 static unsigned getEncodedComdatSelectionKind(const Comdat &C) {
1100   switch (C.getSelectionKind()) {
1101   case Comdat::Any:
1102     return bitc::COMDAT_SELECTION_KIND_ANY;
1103   case Comdat::ExactMatch:
1104     return bitc::COMDAT_SELECTION_KIND_EXACT_MATCH;
1105   case Comdat::Largest:
1106     return bitc::COMDAT_SELECTION_KIND_LARGEST;
1107   case Comdat::NoDuplicates:
1108     return bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES;
1109   case Comdat::SameSize:
1110     return bitc::COMDAT_SELECTION_KIND_SAME_SIZE;
1111   }
1112   llvm_unreachable("Invalid selection kind");
1113 }
1114 
1115 static unsigned getEncodedUnnamedAddr(const GlobalValue &GV) {
1116   switch (GV.getUnnamedAddr()) {
1117   case GlobalValue::UnnamedAddr::None:   return 0;
1118   case GlobalValue::UnnamedAddr::Local:  return 2;
1119   case GlobalValue::UnnamedAddr::Global: return 1;
1120   }
1121   llvm_unreachable("Invalid unnamed_addr");
1122 }
1123 
1124 size_t ModuleBitcodeWriter::addToStrtab(StringRef Str) {
1125   if (GenerateHash)
1126     Hasher.update(Str);
1127   return StrtabBuilder.add(Str);
1128 }
1129 
1130 void ModuleBitcodeWriter::writeComdats() {
1131   SmallVector<unsigned, 64> Vals;
1132   for (const Comdat *C : VE.getComdats()) {
1133     // COMDAT: [strtab offset, strtab size, selection_kind]
1134     Vals.push_back(addToStrtab(C->getName()));
1135     Vals.push_back(C->getName().size());
1136     Vals.push_back(getEncodedComdatSelectionKind(*C));
1137     Stream.EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
1138     Vals.clear();
1139   }
1140 }
1141 
1142 /// Write a record that will eventually hold the word offset of the
1143 /// module-level VST. For now the offset is 0, which will be backpatched
1144 /// after the real VST is written. Saves the bit offset to backpatch.
1145 void ModuleBitcodeWriter::writeValueSymbolTableForwardDecl() {
1146   // Write a placeholder value in for the offset of the real VST,
1147   // which is written after the function blocks so that it can include
1148   // the offset of each function. The placeholder offset will be
1149   // updated when the real VST is written.
1150   auto Abbv = std::make_shared<BitCodeAbbrev>();
1151   Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_VSTOFFSET));
1152   // Blocks are 32-bit aligned, so we can use a 32-bit word offset to
1153   // hold the real VST offset. Must use fixed instead of VBR as we don't
1154   // know how many VBR chunks to reserve ahead of time.
1155   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
1156   unsigned VSTOffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1157 
1158   // Emit the placeholder
1159   uint64_t Vals[] = {bitc::MODULE_CODE_VSTOFFSET, 0};
1160   Stream.EmitRecordWithAbbrev(VSTOffsetAbbrev, Vals);
1161 
1162   // Compute and save the bit offset to the placeholder, which will be
1163   // patched when the real VST is written. We can simply subtract the 32-bit
1164   // fixed size from the current bit number to get the location to backpatch.
1165   VSTOffsetPlaceholder = Stream.GetCurrentBitNo() - 32;
1166 }
1167 
1168 enum StringEncoding { SE_Char6, SE_Fixed7, SE_Fixed8 };
1169 
1170 /// Determine the encoding to use for the given string name and length.
1171 static StringEncoding getStringEncoding(StringRef Str) {
1172   bool isChar6 = true;
1173   for (char C : Str) {
1174     if (isChar6)
1175       isChar6 = BitCodeAbbrevOp::isChar6(C);
1176     if ((unsigned char)C & 128)
1177       // don't bother scanning the rest.
1178       return SE_Fixed8;
1179   }
1180   if (isChar6)
1181     return SE_Char6;
1182   return SE_Fixed7;
1183 }
1184 
1185 /// Emit top-level description of module, including target triple, inline asm,
1186 /// descriptors for global variables, and function prototype info.
1187 /// Returns the bit offset to backpatch with the location of the real VST.
1188 void ModuleBitcodeWriter::writeModuleInfo() {
1189   // Emit various pieces of data attached to a module.
1190   if (!M.getTargetTriple().empty())
1191     writeStringRecord(Stream, bitc::MODULE_CODE_TRIPLE, M.getTargetTriple(),
1192                       0 /*TODO*/);
1193   const std::string &DL = M.getDataLayoutStr();
1194   if (!DL.empty())
1195     writeStringRecord(Stream, bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/);
1196   if (!M.getModuleInlineAsm().empty())
1197     writeStringRecord(Stream, bitc::MODULE_CODE_ASM, M.getModuleInlineAsm(),
1198                       0 /*TODO*/);
1199 
1200   // Emit information about sections and GC, computing how many there are. Also
1201   // compute the maximum alignment value.
1202   std::map<std::string, unsigned> SectionMap;
1203   std::map<std::string, unsigned> GCMap;
1204   MaybeAlign MaxAlignment;
1205   unsigned MaxGlobalType = 0;
1206   const auto UpdateMaxAlignment = [&MaxAlignment](const MaybeAlign A) {
1207     if (A)
1208       MaxAlignment = !MaxAlignment ? *A : std::max(*MaxAlignment, *A);
1209   };
1210   for (const GlobalVariable &GV : M.globals()) {
1211     UpdateMaxAlignment(GV.getAlign());
1212     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getValueType()));
1213     if (GV.hasSection()) {
1214       // Give section names unique ID's.
1215       unsigned &Entry = SectionMap[std::string(GV.getSection())];
1216       if (!Entry) {
1217         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
1218                           0 /*TODO*/);
1219         Entry = SectionMap.size();
1220       }
1221     }
1222   }
1223   for (const Function &F : M) {
1224     UpdateMaxAlignment(F.getAlign());
1225     if (F.hasSection()) {
1226       // Give section names unique ID's.
1227       unsigned &Entry = SectionMap[std::string(F.getSection())];
1228       if (!Entry) {
1229         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
1230                           0 /*TODO*/);
1231         Entry = SectionMap.size();
1232       }
1233     }
1234     if (F.hasGC()) {
1235       // Same for GC names.
1236       unsigned &Entry = GCMap[F.getGC()];
1237       if (!Entry) {
1238         writeStringRecord(Stream, bitc::MODULE_CODE_GCNAME, F.getGC(),
1239                           0 /*TODO*/);
1240         Entry = GCMap.size();
1241       }
1242     }
1243   }
1244 
1245   // Emit abbrev for globals, now that we know # sections and max alignment.
1246   unsigned SimpleGVarAbbrev = 0;
1247   if (!M.global_empty()) {
1248     // Add an abbrev for common globals with no visibility or thread localness.
1249     auto Abbv = std::make_shared<BitCodeAbbrev>();
1250     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
1251     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1252     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1253     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1254                               Log2_32_Ceil(MaxGlobalType+1)));
1255     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddrSpace << 2
1256                                                            //| explicitType << 1
1257                                                            //| constant
1258     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Initializer.
1259     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // Linkage.
1260     if (!MaxAlignment)                                     // Alignment.
1261       Abbv->Add(BitCodeAbbrevOp(0));
1262     else {
1263       unsigned MaxEncAlignment = getEncodedAlign(MaxAlignment);
1264       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1265                                Log2_32_Ceil(MaxEncAlignment+1)));
1266     }
1267     if (SectionMap.empty())                                    // Section.
1268       Abbv->Add(BitCodeAbbrevOp(0));
1269     else
1270       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1271                                Log2_32_Ceil(SectionMap.size()+1)));
1272     // Don't bother emitting vis + thread local.
1273     SimpleGVarAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1274   }
1275 
1276   SmallVector<unsigned, 64> Vals;
1277   // Emit the module's source file name.
1278   {
1279     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
1280     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
1281     if (Bits == SE_Char6)
1282       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
1283     else if (Bits == SE_Fixed7)
1284       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
1285 
1286     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
1287     auto Abbv = std::make_shared<BitCodeAbbrev>();
1288     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
1289     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1290     Abbv->Add(AbbrevOpToUse);
1291     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1292 
1293     for (const auto P : M.getSourceFileName())
1294       Vals.push_back((unsigned char)P);
1295 
1296     // Emit the finished record.
1297     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
1298     Vals.clear();
1299   }
1300 
1301   // Emit the global variable information.
1302   for (const GlobalVariable &GV : M.globals()) {
1303     unsigned AbbrevToUse = 0;
1304 
1305     // GLOBALVAR: [strtab offset, strtab size, type, isconst, initid,
1306     //             linkage, alignment, section, visibility, threadlocal,
1307     //             unnamed_addr, externally_initialized, dllstorageclass,
1308     //             comdat, attributes, DSO_Local]
1309     Vals.push_back(addToStrtab(GV.getName()));
1310     Vals.push_back(GV.getName().size());
1311     Vals.push_back(VE.getTypeID(GV.getValueType()));
1312     Vals.push_back(GV.getType()->getAddressSpace() << 2 | 2 | GV.isConstant());
1313     Vals.push_back(GV.isDeclaration() ? 0 :
1314                    (VE.getValueID(GV.getInitializer()) + 1));
1315     Vals.push_back(getEncodedLinkage(GV));
1316     Vals.push_back(getEncodedAlign(GV.getAlign()));
1317     Vals.push_back(GV.hasSection() ? SectionMap[std::string(GV.getSection())]
1318                                    : 0);
1319     if (GV.isThreadLocal() ||
1320         GV.getVisibility() != GlobalValue::DefaultVisibility ||
1321         GV.getUnnamedAddr() != GlobalValue::UnnamedAddr::None ||
1322         GV.isExternallyInitialized() ||
1323         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
1324         GV.hasComdat() ||
1325         GV.hasAttributes() ||
1326         GV.isDSOLocal() ||
1327         GV.hasPartition()) {
1328       Vals.push_back(getEncodedVisibility(GV));
1329       Vals.push_back(getEncodedThreadLocalMode(GV));
1330       Vals.push_back(getEncodedUnnamedAddr(GV));
1331       Vals.push_back(GV.isExternallyInitialized());
1332       Vals.push_back(getEncodedDLLStorageClass(GV));
1333       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
1334 
1335       auto AL = GV.getAttributesAsList(AttributeList::FunctionIndex);
1336       Vals.push_back(VE.getAttributeListID(AL));
1337 
1338       Vals.push_back(GV.isDSOLocal());
1339       Vals.push_back(addToStrtab(GV.getPartition()));
1340       Vals.push_back(GV.getPartition().size());
1341     } else {
1342       AbbrevToUse = SimpleGVarAbbrev;
1343     }
1344 
1345     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
1346     Vals.clear();
1347   }
1348 
1349   // Emit the function proto information.
1350   for (const Function &F : M) {
1351     // FUNCTION:  [strtab offset, strtab size, type, callingconv, isproto,
1352     //             linkage, paramattrs, alignment, section, visibility, gc,
1353     //             unnamed_addr, prologuedata, dllstorageclass, comdat,
1354     //             prefixdata, personalityfn, DSO_Local, addrspace]
1355     Vals.push_back(addToStrtab(F.getName()));
1356     Vals.push_back(F.getName().size());
1357     Vals.push_back(VE.getTypeID(F.getFunctionType()));
1358     Vals.push_back(F.getCallingConv());
1359     Vals.push_back(F.isDeclaration());
1360     Vals.push_back(getEncodedLinkage(F));
1361     Vals.push_back(VE.getAttributeListID(F.getAttributes()));
1362     Vals.push_back(getEncodedAlign(F.getAlign()));
1363     Vals.push_back(F.hasSection() ? SectionMap[std::string(F.getSection())]
1364                                   : 0);
1365     Vals.push_back(getEncodedVisibility(F));
1366     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
1367     Vals.push_back(getEncodedUnnamedAddr(F));
1368     Vals.push_back(F.hasPrologueData() ? (VE.getValueID(F.getPrologueData()) + 1)
1369                                        : 0);
1370     Vals.push_back(getEncodedDLLStorageClass(F));
1371     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
1372     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
1373                                      : 0);
1374     Vals.push_back(
1375         F.hasPersonalityFn() ? (VE.getValueID(F.getPersonalityFn()) + 1) : 0);
1376 
1377     Vals.push_back(F.isDSOLocal());
1378     Vals.push_back(F.getAddressSpace());
1379     Vals.push_back(addToStrtab(F.getPartition()));
1380     Vals.push_back(F.getPartition().size());
1381 
1382     unsigned AbbrevToUse = 0;
1383     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
1384     Vals.clear();
1385   }
1386 
1387   // Emit the alias information.
1388   for (const GlobalAlias &A : M.aliases()) {
1389     // ALIAS: [strtab offset, strtab size, alias type, aliasee val#, linkage,
1390     //         visibility, dllstorageclass, threadlocal, unnamed_addr,
1391     //         DSO_Local]
1392     Vals.push_back(addToStrtab(A.getName()));
1393     Vals.push_back(A.getName().size());
1394     Vals.push_back(VE.getTypeID(A.getValueType()));
1395     Vals.push_back(A.getType()->getAddressSpace());
1396     Vals.push_back(VE.getValueID(A.getAliasee()));
1397     Vals.push_back(getEncodedLinkage(A));
1398     Vals.push_back(getEncodedVisibility(A));
1399     Vals.push_back(getEncodedDLLStorageClass(A));
1400     Vals.push_back(getEncodedThreadLocalMode(A));
1401     Vals.push_back(getEncodedUnnamedAddr(A));
1402     Vals.push_back(A.isDSOLocal());
1403     Vals.push_back(addToStrtab(A.getPartition()));
1404     Vals.push_back(A.getPartition().size());
1405 
1406     unsigned AbbrevToUse = 0;
1407     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
1408     Vals.clear();
1409   }
1410 
1411   // Emit the ifunc information.
1412   for (const GlobalIFunc &I : M.ifuncs()) {
1413     // IFUNC: [strtab offset, strtab size, ifunc type, address space, resolver
1414     //         val#, linkage, visibility, DSO_Local]
1415     Vals.push_back(addToStrtab(I.getName()));
1416     Vals.push_back(I.getName().size());
1417     Vals.push_back(VE.getTypeID(I.getValueType()));
1418     Vals.push_back(I.getType()->getAddressSpace());
1419     Vals.push_back(VE.getValueID(I.getResolver()));
1420     Vals.push_back(getEncodedLinkage(I));
1421     Vals.push_back(getEncodedVisibility(I));
1422     Vals.push_back(I.isDSOLocal());
1423     Vals.push_back(addToStrtab(I.getPartition()));
1424     Vals.push_back(I.getPartition().size());
1425     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
1426     Vals.clear();
1427   }
1428 
1429   writeValueSymbolTableForwardDecl();
1430 }
1431 
1432 static uint64_t getOptimizationFlags(const Value *V) {
1433   uint64_t Flags = 0;
1434 
1435   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
1436     if (OBO->hasNoSignedWrap())
1437       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
1438     if (OBO->hasNoUnsignedWrap())
1439       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
1440   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
1441     if (PEO->isExact())
1442       Flags |= 1 << bitc::PEO_EXACT;
1443   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
1444     if (FPMO->hasAllowReassoc())
1445       Flags |= bitc::AllowReassoc;
1446     if (FPMO->hasNoNaNs())
1447       Flags |= bitc::NoNaNs;
1448     if (FPMO->hasNoInfs())
1449       Flags |= bitc::NoInfs;
1450     if (FPMO->hasNoSignedZeros())
1451       Flags |= bitc::NoSignedZeros;
1452     if (FPMO->hasAllowReciprocal())
1453       Flags |= bitc::AllowReciprocal;
1454     if (FPMO->hasAllowContract())
1455       Flags |= bitc::AllowContract;
1456     if (FPMO->hasApproxFunc())
1457       Flags |= bitc::ApproxFunc;
1458   }
1459 
1460   return Flags;
1461 }
1462 
1463 void ModuleBitcodeWriter::writeValueAsMetadata(
1464     const ValueAsMetadata *MD, SmallVectorImpl<uint64_t> &Record) {
1465   // Mimic an MDNode with a value as one operand.
1466   Value *V = MD->getValue();
1467   Record.push_back(VE.getTypeID(V->getType()));
1468   Record.push_back(VE.getValueID(V));
1469   Stream.EmitRecord(bitc::METADATA_VALUE, Record, 0);
1470   Record.clear();
1471 }
1472 
1473 void ModuleBitcodeWriter::writeMDTuple(const MDTuple *N,
1474                                        SmallVectorImpl<uint64_t> &Record,
1475                                        unsigned Abbrev) {
1476   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
1477     Metadata *MD = N->getOperand(i);
1478     assert(!(MD && isa<LocalAsMetadata>(MD)) &&
1479            "Unexpected function-local metadata");
1480     Record.push_back(VE.getMetadataOrNullID(MD));
1481   }
1482   Stream.EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
1483                                     : bitc::METADATA_NODE,
1484                     Record, Abbrev);
1485   Record.clear();
1486 }
1487 
1488 unsigned ModuleBitcodeWriter::createDILocationAbbrev() {
1489   // Assume the column is usually under 128, and always output the inlined-at
1490   // location (it's never more expensive than building an array size 1).
1491   auto Abbv = std::make_shared<BitCodeAbbrev>();
1492   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
1493   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1494   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1495   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1496   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1497   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1498   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1499   return Stream.EmitAbbrev(std::move(Abbv));
1500 }
1501 
1502 void ModuleBitcodeWriter::writeDILocation(const DILocation *N,
1503                                           SmallVectorImpl<uint64_t> &Record,
1504                                           unsigned &Abbrev) {
1505   if (!Abbrev)
1506     Abbrev = createDILocationAbbrev();
1507 
1508   Record.push_back(N->isDistinct());
1509   Record.push_back(N->getLine());
1510   Record.push_back(N->getColumn());
1511   Record.push_back(VE.getMetadataID(N->getScope()));
1512   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
1513   Record.push_back(N->isImplicitCode());
1514 
1515   Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
1516   Record.clear();
1517 }
1518 
1519 unsigned ModuleBitcodeWriter::createGenericDINodeAbbrev() {
1520   // Assume the column is usually under 128, and always output the inlined-at
1521   // location (it's never more expensive than building an array size 1).
1522   auto Abbv = std::make_shared<BitCodeAbbrev>();
1523   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
1524   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1525   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1526   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1527   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1528   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1529   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1530   return Stream.EmitAbbrev(std::move(Abbv));
1531 }
1532 
1533 void ModuleBitcodeWriter::writeGenericDINode(const GenericDINode *N,
1534                                              SmallVectorImpl<uint64_t> &Record,
1535                                              unsigned &Abbrev) {
1536   if (!Abbrev)
1537     Abbrev = createGenericDINodeAbbrev();
1538 
1539   Record.push_back(N->isDistinct());
1540   Record.push_back(N->getTag());
1541   Record.push_back(0); // Per-tag version field; unused for now.
1542 
1543   for (auto &I : N->operands())
1544     Record.push_back(VE.getMetadataOrNullID(I));
1545 
1546   Stream.EmitRecord(bitc::METADATA_GENERIC_DEBUG, Record, Abbrev);
1547   Record.clear();
1548 }
1549 
1550 void ModuleBitcodeWriter::writeDISubrange(const DISubrange *N,
1551                                           SmallVectorImpl<uint64_t> &Record,
1552                                           unsigned Abbrev) {
1553   const uint64_t Version = 2 << 1;
1554   Record.push_back((uint64_t)N->isDistinct() | Version);
1555   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1556   Record.push_back(VE.getMetadataOrNullID(N->getRawLowerBound()));
1557   Record.push_back(VE.getMetadataOrNullID(N->getRawUpperBound()));
1558   Record.push_back(VE.getMetadataOrNullID(N->getRawStride()));
1559 
1560   Stream.EmitRecord(bitc::METADATA_SUBRANGE, Record, Abbrev);
1561   Record.clear();
1562 }
1563 
1564 void ModuleBitcodeWriter::writeDIGenericSubrange(
1565     const DIGenericSubrange *N, SmallVectorImpl<uint64_t> &Record,
1566     unsigned Abbrev) {
1567   Record.push_back((uint64_t)N->isDistinct());
1568   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1569   Record.push_back(VE.getMetadataOrNullID(N->getRawLowerBound()));
1570   Record.push_back(VE.getMetadataOrNullID(N->getRawUpperBound()));
1571   Record.push_back(VE.getMetadataOrNullID(N->getRawStride()));
1572 
1573   Stream.EmitRecord(bitc::METADATA_GENERIC_SUBRANGE, Record, Abbrev);
1574   Record.clear();
1575 }
1576 
1577 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
1578   if ((int64_t)V >= 0)
1579     Vals.push_back(V << 1);
1580   else
1581     Vals.push_back((-V << 1) | 1);
1582 }
1583 
1584 static void emitWideAPInt(SmallVectorImpl<uint64_t> &Vals, const APInt &A) {
1585   // We have an arbitrary precision integer value to write whose
1586   // bit width is > 64. However, in canonical unsigned integer
1587   // format it is likely that the high bits are going to be zero.
1588   // So, we only write the number of active words.
1589   unsigned NumWords = A.getActiveWords();
1590   const uint64_t *RawData = A.getRawData();
1591   for (unsigned i = 0; i < NumWords; i++)
1592     emitSignedInt64(Vals, RawData[i]);
1593 }
1594 
1595 void ModuleBitcodeWriter::writeDIEnumerator(const DIEnumerator *N,
1596                                             SmallVectorImpl<uint64_t> &Record,
1597                                             unsigned Abbrev) {
1598   const uint64_t IsBigInt = 1 << 2;
1599   Record.push_back(IsBigInt | (N->isUnsigned() << 1) | N->isDistinct());
1600   Record.push_back(N->getValue().getBitWidth());
1601   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1602   emitWideAPInt(Record, N->getValue());
1603 
1604   Stream.EmitRecord(bitc::METADATA_ENUMERATOR, Record, Abbrev);
1605   Record.clear();
1606 }
1607 
1608 void ModuleBitcodeWriter::writeDIBasicType(const DIBasicType *N,
1609                                            SmallVectorImpl<uint64_t> &Record,
1610                                            unsigned Abbrev) {
1611   Record.push_back(N->isDistinct());
1612   Record.push_back(N->getTag());
1613   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1614   Record.push_back(N->getSizeInBits());
1615   Record.push_back(N->getAlignInBits());
1616   Record.push_back(N->getEncoding());
1617   Record.push_back(N->getFlags());
1618 
1619   Stream.EmitRecord(bitc::METADATA_BASIC_TYPE, Record, Abbrev);
1620   Record.clear();
1621 }
1622 
1623 void ModuleBitcodeWriter::writeDIStringType(const DIStringType *N,
1624                                             SmallVectorImpl<uint64_t> &Record,
1625                                             unsigned Abbrev) {
1626   Record.push_back(N->isDistinct());
1627   Record.push_back(N->getTag());
1628   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1629   Record.push_back(VE.getMetadataOrNullID(N->getStringLength()));
1630   Record.push_back(VE.getMetadataOrNullID(N->getStringLengthExp()));
1631   Record.push_back(N->getSizeInBits());
1632   Record.push_back(N->getAlignInBits());
1633   Record.push_back(N->getEncoding());
1634 
1635   Stream.EmitRecord(bitc::METADATA_STRING_TYPE, Record, Abbrev);
1636   Record.clear();
1637 }
1638 
1639 void ModuleBitcodeWriter::writeDIDerivedType(const DIDerivedType *N,
1640                                              SmallVectorImpl<uint64_t> &Record,
1641                                              unsigned Abbrev) {
1642   Record.push_back(N->isDistinct());
1643   Record.push_back(N->getTag());
1644   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1645   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1646   Record.push_back(N->getLine());
1647   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1648   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1649   Record.push_back(N->getSizeInBits());
1650   Record.push_back(N->getAlignInBits());
1651   Record.push_back(N->getOffsetInBits());
1652   Record.push_back(N->getFlags());
1653   Record.push_back(VE.getMetadataOrNullID(N->getExtraData()));
1654 
1655   // DWARF address space is encoded as N->getDWARFAddressSpace() + 1. 0 means
1656   // that there is no DWARF address space associated with DIDerivedType.
1657   if (const auto &DWARFAddressSpace = N->getDWARFAddressSpace())
1658     Record.push_back(*DWARFAddressSpace + 1);
1659   else
1660     Record.push_back(0);
1661 
1662   Stream.EmitRecord(bitc::METADATA_DERIVED_TYPE, Record, Abbrev);
1663   Record.clear();
1664 }
1665 
1666 void ModuleBitcodeWriter::writeDICompositeType(
1667     const DICompositeType *N, SmallVectorImpl<uint64_t> &Record,
1668     unsigned Abbrev) {
1669   const unsigned IsNotUsedInOldTypeRef = 0x2;
1670   Record.push_back(IsNotUsedInOldTypeRef | (unsigned)N->isDistinct());
1671   Record.push_back(N->getTag());
1672   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1673   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1674   Record.push_back(N->getLine());
1675   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1676   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1677   Record.push_back(N->getSizeInBits());
1678   Record.push_back(N->getAlignInBits());
1679   Record.push_back(N->getOffsetInBits());
1680   Record.push_back(N->getFlags());
1681   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1682   Record.push_back(N->getRuntimeLang());
1683   Record.push_back(VE.getMetadataOrNullID(N->getVTableHolder()));
1684   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1685   Record.push_back(VE.getMetadataOrNullID(N->getRawIdentifier()));
1686   Record.push_back(VE.getMetadataOrNullID(N->getDiscriminator()));
1687   Record.push_back(VE.getMetadataOrNullID(N->getRawDataLocation()));
1688   Record.push_back(VE.getMetadataOrNullID(N->getRawAssociated()));
1689   Record.push_back(VE.getMetadataOrNullID(N->getRawAllocated()));
1690   Record.push_back(VE.getMetadataOrNullID(N->getRawRank()));
1691 
1692   Stream.EmitRecord(bitc::METADATA_COMPOSITE_TYPE, Record, Abbrev);
1693   Record.clear();
1694 }
1695 
1696 void ModuleBitcodeWriter::writeDISubroutineType(
1697     const DISubroutineType *N, SmallVectorImpl<uint64_t> &Record,
1698     unsigned Abbrev) {
1699   const unsigned HasNoOldTypeRefs = 0x2;
1700   Record.push_back(HasNoOldTypeRefs | (unsigned)N->isDistinct());
1701   Record.push_back(N->getFlags());
1702   Record.push_back(VE.getMetadataOrNullID(N->getTypeArray().get()));
1703   Record.push_back(N->getCC());
1704 
1705   Stream.EmitRecord(bitc::METADATA_SUBROUTINE_TYPE, Record, Abbrev);
1706   Record.clear();
1707 }
1708 
1709 void ModuleBitcodeWriter::writeDIFile(const DIFile *N,
1710                                       SmallVectorImpl<uint64_t> &Record,
1711                                       unsigned Abbrev) {
1712   Record.push_back(N->isDistinct());
1713   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
1714   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
1715   if (N->getRawChecksum()) {
1716     Record.push_back(N->getRawChecksum()->Kind);
1717     Record.push_back(VE.getMetadataOrNullID(N->getRawChecksum()->Value));
1718   } else {
1719     // Maintain backwards compatibility with the old internal representation of
1720     // CSK_None in ChecksumKind by writing nulls here when Checksum is None.
1721     Record.push_back(0);
1722     Record.push_back(VE.getMetadataOrNullID(nullptr));
1723   }
1724   auto Source = N->getRawSource();
1725   if (Source)
1726     Record.push_back(VE.getMetadataOrNullID(*Source));
1727 
1728   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
1729   Record.clear();
1730 }
1731 
1732 void ModuleBitcodeWriter::writeDICompileUnit(const DICompileUnit *N,
1733                                              SmallVectorImpl<uint64_t> &Record,
1734                                              unsigned Abbrev) {
1735   assert(N->isDistinct() && "Expected distinct compile units");
1736   Record.push_back(/* IsDistinct */ true);
1737   Record.push_back(N->getSourceLanguage());
1738   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1739   Record.push_back(VE.getMetadataOrNullID(N->getRawProducer()));
1740   Record.push_back(N->isOptimized());
1741   Record.push_back(VE.getMetadataOrNullID(N->getRawFlags()));
1742   Record.push_back(N->getRuntimeVersion());
1743   Record.push_back(VE.getMetadataOrNullID(N->getRawSplitDebugFilename()));
1744   Record.push_back(N->getEmissionKind());
1745   Record.push_back(VE.getMetadataOrNullID(N->getEnumTypes().get()));
1746   Record.push_back(VE.getMetadataOrNullID(N->getRetainedTypes().get()));
1747   Record.push_back(/* subprograms */ 0);
1748   Record.push_back(VE.getMetadataOrNullID(N->getGlobalVariables().get()));
1749   Record.push_back(VE.getMetadataOrNullID(N->getImportedEntities().get()));
1750   Record.push_back(N->getDWOId());
1751   Record.push_back(VE.getMetadataOrNullID(N->getMacros().get()));
1752   Record.push_back(N->getSplitDebugInlining());
1753   Record.push_back(N->getDebugInfoForProfiling());
1754   Record.push_back((unsigned)N->getNameTableKind());
1755   Record.push_back(N->getRangesBaseAddress());
1756   Record.push_back(VE.getMetadataOrNullID(N->getRawSysRoot()));
1757   Record.push_back(VE.getMetadataOrNullID(N->getRawSDK()));
1758 
1759   Stream.EmitRecord(bitc::METADATA_COMPILE_UNIT, Record, Abbrev);
1760   Record.clear();
1761 }
1762 
1763 void ModuleBitcodeWriter::writeDISubprogram(const DISubprogram *N,
1764                                             SmallVectorImpl<uint64_t> &Record,
1765                                             unsigned Abbrev) {
1766   const uint64_t HasUnitFlag = 1 << 1;
1767   const uint64_t HasSPFlagsFlag = 1 << 2;
1768   Record.push_back(uint64_t(N->isDistinct()) | HasUnitFlag | HasSPFlagsFlag);
1769   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1770   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1771   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1772   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1773   Record.push_back(N->getLine());
1774   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1775   Record.push_back(N->getScopeLine());
1776   Record.push_back(VE.getMetadataOrNullID(N->getContainingType()));
1777   Record.push_back(N->getSPFlags());
1778   Record.push_back(N->getVirtualIndex());
1779   Record.push_back(N->getFlags());
1780   Record.push_back(VE.getMetadataOrNullID(N->getRawUnit()));
1781   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1782   Record.push_back(VE.getMetadataOrNullID(N->getDeclaration()));
1783   Record.push_back(VE.getMetadataOrNullID(N->getRetainedNodes().get()));
1784   Record.push_back(N->getThisAdjustment());
1785   Record.push_back(VE.getMetadataOrNullID(N->getThrownTypes().get()));
1786 
1787   Stream.EmitRecord(bitc::METADATA_SUBPROGRAM, Record, Abbrev);
1788   Record.clear();
1789 }
1790 
1791 void ModuleBitcodeWriter::writeDILexicalBlock(const DILexicalBlock *N,
1792                                               SmallVectorImpl<uint64_t> &Record,
1793                                               unsigned Abbrev) {
1794   Record.push_back(N->isDistinct());
1795   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1796   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1797   Record.push_back(N->getLine());
1798   Record.push_back(N->getColumn());
1799 
1800   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK, Record, Abbrev);
1801   Record.clear();
1802 }
1803 
1804 void ModuleBitcodeWriter::writeDILexicalBlockFile(
1805     const DILexicalBlockFile *N, SmallVectorImpl<uint64_t> &Record,
1806     unsigned Abbrev) {
1807   Record.push_back(N->isDistinct());
1808   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1809   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1810   Record.push_back(N->getDiscriminator());
1811 
1812   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK_FILE, Record, Abbrev);
1813   Record.clear();
1814 }
1815 
1816 void ModuleBitcodeWriter::writeDICommonBlock(const DICommonBlock *N,
1817                                              SmallVectorImpl<uint64_t> &Record,
1818                                              unsigned Abbrev) {
1819   Record.push_back(N->isDistinct());
1820   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1821   Record.push_back(VE.getMetadataOrNullID(N->getDecl()));
1822   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1823   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1824   Record.push_back(N->getLineNo());
1825 
1826   Stream.EmitRecord(bitc::METADATA_COMMON_BLOCK, Record, Abbrev);
1827   Record.clear();
1828 }
1829 
1830 void ModuleBitcodeWriter::writeDINamespace(const DINamespace *N,
1831                                            SmallVectorImpl<uint64_t> &Record,
1832                                            unsigned Abbrev) {
1833   Record.push_back(N->isDistinct() | N->getExportSymbols() << 1);
1834   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1835   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1836 
1837   Stream.EmitRecord(bitc::METADATA_NAMESPACE, Record, Abbrev);
1838   Record.clear();
1839 }
1840 
1841 void ModuleBitcodeWriter::writeDIMacro(const DIMacro *N,
1842                                        SmallVectorImpl<uint64_t> &Record,
1843                                        unsigned Abbrev) {
1844   Record.push_back(N->isDistinct());
1845   Record.push_back(N->getMacinfoType());
1846   Record.push_back(N->getLine());
1847   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1848   Record.push_back(VE.getMetadataOrNullID(N->getRawValue()));
1849 
1850   Stream.EmitRecord(bitc::METADATA_MACRO, Record, Abbrev);
1851   Record.clear();
1852 }
1853 
1854 void ModuleBitcodeWriter::writeDIMacroFile(const DIMacroFile *N,
1855                                            SmallVectorImpl<uint64_t> &Record,
1856                                            unsigned Abbrev) {
1857   Record.push_back(N->isDistinct());
1858   Record.push_back(N->getMacinfoType());
1859   Record.push_back(N->getLine());
1860   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1861   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1862 
1863   Stream.EmitRecord(bitc::METADATA_MACRO_FILE, Record, Abbrev);
1864   Record.clear();
1865 }
1866 
1867 void ModuleBitcodeWriter::writeDIModule(const DIModule *N,
1868                                         SmallVectorImpl<uint64_t> &Record,
1869                                         unsigned Abbrev) {
1870   Record.push_back(N->isDistinct());
1871   for (auto &I : N->operands())
1872     Record.push_back(VE.getMetadataOrNullID(I));
1873   Record.push_back(N->getLineNo());
1874   Record.push_back(N->getIsDecl());
1875 
1876   Stream.EmitRecord(bitc::METADATA_MODULE, Record, Abbrev);
1877   Record.clear();
1878 }
1879 
1880 void ModuleBitcodeWriter::writeDITemplateTypeParameter(
1881     const DITemplateTypeParameter *N, SmallVectorImpl<uint64_t> &Record,
1882     unsigned Abbrev) {
1883   Record.push_back(N->isDistinct());
1884   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1885   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1886   Record.push_back(N->isDefault());
1887 
1888   Stream.EmitRecord(bitc::METADATA_TEMPLATE_TYPE, Record, Abbrev);
1889   Record.clear();
1890 }
1891 
1892 void ModuleBitcodeWriter::writeDITemplateValueParameter(
1893     const DITemplateValueParameter *N, SmallVectorImpl<uint64_t> &Record,
1894     unsigned Abbrev) {
1895   Record.push_back(N->isDistinct());
1896   Record.push_back(N->getTag());
1897   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1898   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1899   Record.push_back(N->isDefault());
1900   Record.push_back(VE.getMetadataOrNullID(N->getValue()));
1901 
1902   Stream.EmitRecord(bitc::METADATA_TEMPLATE_VALUE, Record, Abbrev);
1903   Record.clear();
1904 }
1905 
1906 void ModuleBitcodeWriter::writeDIGlobalVariable(
1907     const DIGlobalVariable *N, SmallVectorImpl<uint64_t> &Record,
1908     unsigned Abbrev) {
1909   const uint64_t Version = 2 << 1;
1910   Record.push_back((uint64_t)N->isDistinct() | Version);
1911   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1912   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1913   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1914   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1915   Record.push_back(N->getLine());
1916   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1917   Record.push_back(N->isLocalToUnit());
1918   Record.push_back(N->isDefinition());
1919   Record.push_back(VE.getMetadataOrNullID(N->getStaticDataMemberDeclaration()));
1920   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams()));
1921   Record.push_back(N->getAlignInBits());
1922 
1923   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR, Record, Abbrev);
1924   Record.clear();
1925 }
1926 
1927 void ModuleBitcodeWriter::writeDILocalVariable(
1928     const DILocalVariable *N, SmallVectorImpl<uint64_t> &Record,
1929     unsigned Abbrev) {
1930   // In order to support all possible bitcode formats in BitcodeReader we need
1931   // to distinguish the following cases:
1932   // 1) Record has no artificial tag (Record[1]),
1933   //   has no obsolete inlinedAt field (Record[9]).
1934   //   In this case Record size will be 8, HasAlignment flag is false.
1935   // 2) Record has artificial tag (Record[1]),
1936   //   has no obsolete inlignedAt field (Record[9]).
1937   //   In this case Record size will be 9, HasAlignment flag is false.
1938   // 3) Record has both artificial tag (Record[1]) and
1939   //   obsolete inlignedAt field (Record[9]).
1940   //   In this case Record size will be 10, HasAlignment flag is false.
1941   // 4) Record has neither artificial tag, nor inlignedAt field, but
1942   //   HasAlignment flag is true and Record[8] contains alignment value.
1943   const uint64_t HasAlignmentFlag = 1 << 1;
1944   Record.push_back((uint64_t)N->isDistinct() | HasAlignmentFlag);
1945   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1946   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1947   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1948   Record.push_back(N->getLine());
1949   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1950   Record.push_back(N->getArg());
1951   Record.push_back(N->getFlags());
1952   Record.push_back(N->getAlignInBits());
1953 
1954   Stream.EmitRecord(bitc::METADATA_LOCAL_VAR, Record, Abbrev);
1955   Record.clear();
1956 }
1957 
1958 void ModuleBitcodeWriter::writeDILabel(
1959     const DILabel *N, SmallVectorImpl<uint64_t> &Record,
1960     unsigned Abbrev) {
1961   Record.push_back((uint64_t)N->isDistinct());
1962   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1963   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1964   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1965   Record.push_back(N->getLine());
1966 
1967   Stream.EmitRecord(bitc::METADATA_LABEL, Record, Abbrev);
1968   Record.clear();
1969 }
1970 
1971 void ModuleBitcodeWriter::writeDIExpression(const DIExpression *N,
1972                                             SmallVectorImpl<uint64_t> &Record,
1973                                             unsigned Abbrev) {
1974   Record.reserve(N->getElements().size() + 1);
1975   const uint64_t Version = 3 << 1;
1976   Record.push_back((uint64_t)N->isDistinct() | Version);
1977   Record.append(N->elements_begin(), N->elements_end());
1978 
1979   Stream.EmitRecord(bitc::METADATA_EXPRESSION, Record, Abbrev);
1980   Record.clear();
1981 }
1982 
1983 void ModuleBitcodeWriter::writeDIGlobalVariableExpression(
1984     const DIGlobalVariableExpression *N, SmallVectorImpl<uint64_t> &Record,
1985     unsigned Abbrev) {
1986   Record.push_back(N->isDistinct());
1987   Record.push_back(VE.getMetadataOrNullID(N->getVariable()));
1988   Record.push_back(VE.getMetadataOrNullID(N->getExpression()));
1989 
1990   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR_EXPR, Record, Abbrev);
1991   Record.clear();
1992 }
1993 
1994 void ModuleBitcodeWriter::writeDIObjCProperty(const DIObjCProperty *N,
1995                                               SmallVectorImpl<uint64_t> &Record,
1996                                               unsigned Abbrev) {
1997   Record.push_back(N->isDistinct());
1998   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1999   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2000   Record.push_back(N->getLine());
2001   Record.push_back(VE.getMetadataOrNullID(N->getRawSetterName()));
2002   Record.push_back(VE.getMetadataOrNullID(N->getRawGetterName()));
2003   Record.push_back(N->getAttributes());
2004   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2005 
2006   Stream.EmitRecord(bitc::METADATA_OBJC_PROPERTY, Record, Abbrev);
2007   Record.clear();
2008 }
2009 
2010 void ModuleBitcodeWriter::writeDIImportedEntity(
2011     const DIImportedEntity *N, SmallVectorImpl<uint64_t> &Record,
2012     unsigned Abbrev) {
2013   Record.push_back(N->isDistinct());
2014   Record.push_back(N->getTag());
2015   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2016   Record.push_back(VE.getMetadataOrNullID(N->getEntity()));
2017   Record.push_back(N->getLine());
2018   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2019   Record.push_back(VE.getMetadataOrNullID(N->getRawFile()));
2020 
2021   Stream.EmitRecord(bitc::METADATA_IMPORTED_ENTITY, Record, Abbrev);
2022   Record.clear();
2023 }
2024 
2025 unsigned ModuleBitcodeWriter::createNamedMetadataAbbrev() {
2026   auto Abbv = std::make_shared<BitCodeAbbrev>();
2027   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
2028   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2029   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2030   return Stream.EmitAbbrev(std::move(Abbv));
2031 }
2032 
2033 void ModuleBitcodeWriter::writeNamedMetadata(
2034     SmallVectorImpl<uint64_t> &Record) {
2035   if (M.named_metadata_empty())
2036     return;
2037 
2038   unsigned Abbrev = createNamedMetadataAbbrev();
2039   for (const NamedMDNode &NMD : M.named_metadata()) {
2040     // Write name.
2041     StringRef Str = NMD.getName();
2042     Record.append(Str.bytes_begin(), Str.bytes_end());
2043     Stream.EmitRecord(bitc::METADATA_NAME, Record, Abbrev);
2044     Record.clear();
2045 
2046     // Write named metadata operands.
2047     for (const MDNode *N : NMD.operands())
2048       Record.push_back(VE.getMetadataID(N));
2049     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
2050     Record.clear();
2051   }
2052 }
2053 
2054 unsigned ModuleBitcodeWriter::createMetadataStringsAbbrev() {
2055   auto Abbv = std::make_shared<BitCodeAbbrev>();
2056   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRINGS));
2057   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // # of strings
2058   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // offset to chars
2059   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
2060   return Stream.EmitAbbrev(std::move(Abbv));
2061 }
2062 
2063 /// Write out a record for MDString.
2064 ///
2065 /// All the metadata strings in a metadata block are emitted in a single
2066 /// record.  The sizes and strings themselves are shoved into a blob.
2067 void ModuleBitcodeWriter::writeMetadataStrings(
2068     ArrayRef<const Metadata *> Strings, SmallVectorImpl<uint64_t> &Record) {
2069   if (Strings.empty())
2070     return;
2071 
2072   // Start the record with the number of strings.
2073   Record.push_back(bitc::METADATA_STRINGS);
2074   Record.push_back(Strings.size());
2075 
2076   // Emit the sizes of the strings in the blob.
2077   SmallString<256> Blob;
2078   {
2079     BitstreamWriter W(Blob);
2080     for (const Metadata *MD : Strings)
2081       W.EmitVBR(cast<MDString>(MD)->getLength(), 6);
2082     W.FlushToWord();
2083   }
2084 
2085   // Add the offset to the strings to the record.
2086   Record.push_back(Blob.size());
2087 
2088   // Add the strings to the blob.
2089   for (const Metadata *MD : Strings)
2090     Blob.append(cast<MDString>(MD)->getString());
2091 
2092   // Emit the final record.
2093   Stream.EmitRecordWithBlob(createMetadataStringsAbbrev(), Record, Blob);
2094   Record.clear();
2095 }
2096 
2097 // Generates an enum to use as an index in the Abbrev array of Metadata record.
2098 enum MetadataAbbrev : unsigned {
2099 #define HANDLE_MDNODE_LEAF(CLASS) CLASS##AbbrevID,
2100 #include "llvm/IR/Metadata.def"
2101   LastPlusOne
2102 };
2103 
2104 void ModuleBitcodeWriter::writeMetadataRecords(
2105     ArrayRef<const Metadata *> MDs, SmallVectorImpl<uint64_t> &Record,
2106     std::vector<unsigned> *MDAbbrevs, std::vector<uint64_t> *IndexPos) {
2107   if (MDs.empty())
2108     return;
2109 
2110   // Initialize MDNode abbreviations.
2111 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
2112 #include "llvm/IR/Metadata.def"
2113 
2114   for (const Metadata *MD : MDs) {
2115     if (IndexPos)
2116       IndexPos->push_back(Stream.GetCurrentBitNo());
2117     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
2118       assert(N->isResolved() && "Expected forward references to be resolved");
2119 
2120       switch (N->getMetadataID()) {
2121       default:
2122         llvm_unreachable("Invalid MDNode subclass");
2123 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
2124   case Metadata::CLASS##Kind:                                                  \
2125     if (MDAbbrevs)                                                             \
2126       write##CLASS(cast<CLASS>(N), Record,                                     \
2127                    (*MDAbbrevs)[MetadataAbbrev::CLASS##AbbrevID]);             \
2128     else                                                                       \
2129       write##CLASS(cast<CLASS>(N), Record, CLASS##Abbrev);                     \
2130     continue;
2131 #include "llvm/IR/Metadata.def"
2132       }
2133     }
2134     writeValueAsMetadata(cast<ValueAsMetadata>(MD), Record);
2135   }
2136 }
2137 
2138 void ModuleBitcodeWriter::writeModuleMetadata() {
2139   if (!VE.hasMDs() && M.named_metadata_empty())
2140     return;
2141 
2142   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 4);
2143   SmallVector<uint64_t, 64> Record;
2144 
2145   // Emit all abbrevs upfront, so that the reader can jump in the middle of the
2146   // block and load any metadata.
2147   std::vector<unsigned> MDAbbrevs;
2148 
2149   MDAbbrevs.resize(MetadataAbbrev::LastPlusOne);
2150   MDAbbrevs[MetadataAbbrev::DILocationAbbrevID] = createDILocationAbbrev();
2151   MDAbbrevs[MetadataAbbrev::GenericDINodeAbbrevID] =
2152       createGenericDINodeAbbrev();
2153 
2154   auto Abbv = std::make_shared<BitCodeAbbrev>();
2155   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX_OFFSET));
2156   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2157   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2158   unsigned OffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2159 
2160   Abbv = std::make_shared<BitCodeAbbrev>();
2161   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX));
2162   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2163   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2164   unsigned IndexAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2165 
2166   // Emit MDStrings together upfront.
2167   writeMetadataStrings(VE.getMDStrings(), Record);
2168 
2169   // We only emit an index for the metadata record if we have more than a given
2170   // (naive) threshold of metadatas, otherwise it is not worth it.
2171   if (VE.getNonMDStrings().size() > IndexThreshold) {
2172     // Write a placeholder value in for the offset of the metadata index,
2173     // which is written after the records, so that it can include
2174     // the offset of each entry. The placeholder offset will be
2175     // updated after all records are emitted.
2176     uint64_t Vals[] = {0, 0};
2177     Stream.EmitRecord(bitc::METADATA_INDEX_OFFSET, Vals, OffsetAbbrev);
2178   }
2179 
2180   // Compute and save the bit offset to the current position, which will be
2181   // patched when we emit the index later. We can simply subtract the 64-bit
2182   // fixed size from the current bit number to get the location to backpatch.
2183   uint64_t IndexOffsetRecordBitPos = Stream.GetCurrentBitNo();
2184 
2185   // This index will contain the bitpos for each individual record.
2186   std::vector<uint64_t> IndexPos;
2187   IndexPos.reserve(VE.getNonMDStrings().size());
2188 
2189   // Write all the records
2190   writeMetadataRecords(VE.getNonMDStrings(), Record, &MDAbbrevs, &IndexPos);
2191 
2192   if (VE.getNonMDStrings().size() > IndexThreshold) {
2193     // Now that we have emitted all the records we will emit the index. But
2194     // first
2195     // backpatch the forward reference so that the reader can skip the records
2196     // efficiently.
2197     Stream.BackpatchWord64(IndexOffsetRecordBitPos - 64,
2198                            Stream.GetCurrentBitNo() - IndexOffsetRecordBitPos);
2199 
2200     // Delta encode the index.
2201     uint64_t PreviousValue = IndexOffsetRecordBitPos;
2202     for (auto &Elt : IndexPos) {
2203       auto EltDelta = Elt - PreviousValue;
2204       PreviousValue = Elt;
2205       Elt = EltDelta;
2206     }
2207     // Emit the index record.
2208     Stream.EmitRecord(bitc::METADATA_INDEX, IndexPos, IndexAbbrev);
2209     IndexPos.clear();
2210   }
2211 
2212   // Write the named metadata now.
2213   writeNamedMetadata(Record);
2214 
2215   auto AddDeclAttachedMetadata = [&](const GlobalObject &GO) {
2216     SmallVector<uint64_t, 4> Record;
2217     Record.push_back(VE.getValueID(&GO));
2218     pushGlobalMetadataAttachment(Record, GO);
2219     Stream.EmitRecord(bitc::METADATA_GLOBAL_DECL_ATTACHMENT, Record);
2220   };
2221   for (const Function &F : M)
2222     if (F.isDeclaration() && F.hasMetadata())
2223       AddDeclAttachedMetadata(F);
2224   // FIXME: Only store metadata for declarations here, and move data for global
2225   // variable definitions to a separate block (PR28134).
2226   for (const GlobalVariable &GV : M.globals())
2227     if (GV.hasMetadata())
2228       AddDeclAttachedMetadata(GV);
2229 
2230   Stream.ExitBlock();
2231 }
2232 
2233 void ModuleBitcodeWriter::writeFunctionMetadata(const Function &F) {
2234   if (!VE.hasMDs())
2235     return;
2236 
2237   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
2238   SmallVector<uint64_t, 64> Record;
2239   writeMetadataStrings(VE.getMDStrings(), Record);
2240   writeMetadataRecords(VE.getNonMDStrings(), Record);
2241   Stream.ExitBlock();
2242 }
2243 
2244 void ModuleBitcodeWriter::pushGlobalMetadataAttachment(
2245     SmallVectorImpl<uint64_t> &Record, const GlobalObject &GO) {
2246   // [n x [id, mdnode]]
2247   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2248   GO.getAllMetadata(MDs);
2249   for (const auto &I : MDs) {
2250     Record.push_back(I.first);
2251     Record.push_back(VE.getMetadataID(I.second));
2252   }
2253 }
2254 
2255 void ModuleBitcodeWriter::writeFunctionMetadataAttachment(const Function &F) {
2256   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
2257 
2258   SmallVector<uint64_t, 64> Record;
2259 
2260   if (F.hasMetadata()) {
2261     pushGlobalMetadataAttachment(Record, F);
2262     Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2263     Record.clear();
2264   }
2265 
2266   // Write metadata attachments
2267   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
2268   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2269   for (const BasicBlock &BB : F)
2270     for (const Instruction &I : BB) {
2271       MDs.clear();
2272       I.getAllMetadataOtherThanDebugLoc(MDs);
2273 
2274       // If no metadata, ignore instruction.
2275       if (MDs.empty()) continue;
2276 
2277       Record.push_back(VE.getInstructionID(&I));
2278 
2279       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
2280         Record.push_back(MDs[i].first);
2281         Record.push_back(VE.getMetadataID(MDs[i].second));
2282       }
2283       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2284       Record.clear();
2285     }
2286 
2287   Stream.ExitBlock();
2288 }
2289 
2290 void ModuleBitcodeWriter::writeModuleMetadataKinds() {
2291   SmallVector<uint64_t, 64> Record;
2292 
2293   // Write metadata kinds
2294   // METADATA_KIND - [n x [id, name]]
2295   SmallVector<StringRef, 8> Names;
2296   M.getMDKindNames(Names);
2297 
2298   if (Names.empty()) return;
2299 
2300   Stream.EnterSubblock(bitc::METADATA_KIND_BLOCK_ID, 3);
2301 
2302   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
2303     Record.push_back(MDKindID);
2304     StringRef KName = Names[MDKindID];
2305     Record.append(KName.begin(), KName.end());
2306 
2307     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
2308     Record.clear();
2309   }
2310 
2311   Stream.ExitBlock();
2312 }
2313 
2314 void ModuleBitcodeWriter::writeOperandBundleTags() {
2315   // Write metadata kinds
2316   //
2317   // OPERAND_BUNDLE_TAGS_BLOCK_ID : N x OPERAND_BUNDLE_TAG
2318   //
2319   // OPERAND_BUNDLE_TAG - [strchr x N]
2320 
2321   SmallVector<StringRef, 8> Tags;
2322   M.getOperandBundleTags(Tags);
2323 
2324   if (Tags.empty())
2325     return;
2326 
2327   Stream.EnterSubblock(bitc::OPERAND_BUNDLE_TAGS_BLOCK_ID, 3);
2328 
2329   SmallVector<uint64_t, 64> Record;
2330 
2331   for (auto Tag : Tags) {
2332     Record.append(Tag.begin(), Tag.end());
2333 
2334     Stream.EmitRecord(bitc::OPERAND_BUNDLE_TAG, Record, 0);
2335     Record.clear();
2336   }
2337 
2338   Stream.ExitBlock();
2339 }
2340 
2341 void ModuleBitcodeWriter::writeSyncScopeNames() {
2342   SmallVector<StringRef, 8> SSNs;
2343   M.getContext().getSyncScopeNames(SSNs);
2344   if (SSNs.empty())
2345     return;
2346 
2347   Stream.EnterSubblock(bitc::SYNC_SCOPE_NAMES_BLOCK_ID, 2);
2348 
2349   SmallVector<uint64_t, 64> Record;
2350   for (auto SSN : SSNs) {
2351     Record.append(SSN.begin(), SSN.end());
2352     Stream.EmitRecord(bitc::SYNC_SCOPE_NAME, Record, 0);
2353     Record.clear();
2354   }
2355 
2356   Stream.ExitBlock();
2357 }
2358 
2359 void ModuleBitcodeWriter::writeConstants(unsigned FirstVal, unsigned LastVal,
2360                                          bool isGlobal) {
2361   if (FirstVal == LastVal) return;
2362 
2363   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
2364 
2365   unsigned AggregateAbbrev = 0;
2366   unsigned String8Abbrev = 0;
2367   unsigned CString7Abbrev = 0;
2368   unsigned CString6Abbrev = 0;
2369   // If this is a constant pool for the module, emit module-specific abbrevs.
2370   if (isGlobal) {
2371     // Abbrev for CST_CODE_AGGREGATE.
2372     auto Abbv = std::make_shared<BitCodeAbbrev>();
2373     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
2374     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2375     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
2376     AggregateAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2377 
2378     // Abbrev for CST_CODE_STRING.
2379     Abbv = std::make_shared<BitCodeAbbrev>();
2380     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
2381     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2382     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2383     String8Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2384     // Abbrev for CST_CODE_CSTRING.
2385     Abbv = std::make_shared<BitCodeAbbrev>();
2386     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2387     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2388     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2389     CString7Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2390     // Abbrev for CST_CODE_CSTRING.
2391     Abbv = std::make_shared<BitCodeAbbrev>();
2392     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2393     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2394     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2395     CString6Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2396   }
2397 
2398   SmallVector<uint64_t, 64> Record;
2399 
2400   const ValueEnumerator::ValueList &Vals = VE.getValues();
2401   Type *LastTy = nullptr;
2402   for (unsigned i = FirstVal; i != LastVal; ++i) {
2403     const Value *V = Vals[i].first;
2404     // If we need to switch types, do so now.
2405     if (V->getType() != LastTy) {
2406       LastTy = V->getType();
2407       Record.push_back(VE.getTypeID(LastTy));
2408       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
2409                         CONSTANTS_SETTYPE_ABBREV);
2410       Record.clear();
2411     }
2412 
2413     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
2414       Record.push_back(unsigned(IA->hasSideEffects()) |
2415                        unsigned(IA->isAlignStack()) << 1 |
2416                        unsigned(IA->getDialect()&1) << 2);
2417 
2418       // Add the asm string.
2419       const std::string &AsmStr = IA->getAsmString();
2420       Record.push_back(AsmStr.size());
2421       Record.append(AsmStr.begin(), AsmStr.end());
2422 
2423       // Add the constraint string.
2424       const std::string &ConstraintStr = IA->getConstraintString();
2425       Record.push_back(ConstraintStr.size());
2426       Record.append(ConstraintStr.begin(), ConstraintStr.end());
2427       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
2428       Record.clear();
2429       continue;
2430     }
2431     const Constant *C = cast<Constant>(V);
2432     unsigned Code = -1U;
2433     unsigned AbbrevToUse = 0;
2434     if (C->isNullValue()) {
2435       Code = bitc::CST_CODE_NULL;
2436     } else if (isa<PoisonValue>(C)) {
2437       Code = bitc::CST_CODE_POISON;
2438     } else if (isa<UndefValue>(C)) {
2439       Code = bitc::CST_CODE_UNDEF;
2440     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
2441       if (IV->getBitWidth() <= 64) {
2442         uint64_t V = IV->getSExtValue();
2443         emitSignedInt64(Record, V);
2444         Code = bitc::CST_CODE_INTEGER;
2445         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
2446       } else {                             // Wide integers, > 64 bits in size.
2447         emitWideAPInt(Record, IV->getValue());
2448         Code = bitc::CST_CODE_WIDE_INTEGER;
2449       }
2450     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
2451       Code = bitc::CST_CODE_FLOAT;
2452       Type *Ty = CFP->getType();
2453       if (Ty->isHalfTy() || Ty->isBFloatTy() || Ty->isFloatTy() ||
2454           Ty->isDoubleTy()) {
2455         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
2456       } else if (Ty->isX86_FP80Ty()) {
2457         // api needed to prevent premature destruction
2458         // bits are not in the same order as a normal i80 APInt, compensate.
2459         APInt api = CFP->getValueAPF().bitcastToAPInt();
2460         const uint64_t *p = api.getRawData();
2461         Record.push_back((p[1] << 48) | (p[0] >> 16));
2462         Record.push_back(p[0] & 0xffffLL);
2463       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
2464         APInt api = CFP->getValueAPF().bitcastToAPInt();
2465         const uint64_t *p = api.getRawData();
2466         Record.push_back(p[0]);
2467         Record.push_back(p[1]);
2468       } else {
2469         assert(0 && "Unknown FP type!");
2470       }
2471     } else if (isa<ConstantDataSequential>(C) &&
2472                cast<ConstantDataSequential>(C)->isString()) {
2473       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
2474       // Emit constant strings specially.
2475       unsigned NumElts = Str->getNumElements();
2476       // If this is a null-terminated string, use the denser CSTRING encoding.
2477       if (Str->isCString()) {
2478         Code = bitc::CST_CODE_CSTRING;
2479         --NumElts;  // Don't encode the null, which isn't allowed by char6.
2480       } else {
2481         Code = bitc::CST_CODE_STRING;
2482         AbbrevToUse = String8Abbrev;
2483       }
2484       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
2485       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
2486       for (unsigned i = 0; i != NumElts; ++i) {
2487         unsigned char V = Str->getElementAsInteger(i);
2488         Record.push_back(V);
2489         isCStr7 &= (V & 128) == 0;
2490         if (isCStrChar6)
2491           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
2492       }
2493 
2494       if (isCStrChar6)
2495         AbbrevToUse = CString6Abbrev;
2496       else if (isCStr7)
2497         AbbrevToUse = CString7Abbrev;
2498     } else if (const ConstantDataSequential *CDS =
2499                   dyn_cast<ConstantDataSequential>(C)) {
2500       Code = bitc::CST_CODE_DATA;
2501       Type *EltTy = CDS->getElementType();
2502       if (isa<IntegerType>(EltTy)) {
2503         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2504           Record.push_back(CDS->getElementAsInteger(i));
2505       } else {
2506         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2507           Record.push_back(
2508               CDS->getElementAsAPFloat(i).bitcastToAPInt().getLimitedValue());
2509       }
2510     } else if (isa<ConstantAggregate>(C)) {
2511       Code = bitc::CST_CODE_AGGREGATE;
2512       for (const Value *Op : C->operands())
2513         Record.push_back(VE.getValueID(Op));
2514       AbbrevToUse = AggregateAbbrev;
2515     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
2516       switch (CE->getOpcode()) {
2517       default:
2518         if (Instruction::isCast(CE->getOpcode())) {
2519           Code = bitc::CST_CODE_CE_CAST;
2520           Record.push_back(getEncodedCastOpcode(CE->getOpcode()));
2521           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2522           Record.push_back(VE.getValueID(C->getOperand(0)));
2523           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
2524         } else {
2525           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
2526           Code = bitc::CST_CODE_CE_BINOP;
2527           Record.push_back(getEncodedBinaryOpcode(CE->getOpcode()));
2528           Record.push_back(VE.getValueID(C->getOperand(0)));
2529           Record.push_back(VE.getValueID(C->getOperand(1)));
2530           uint64_t Flags = getOptimizationFlags(CE);
2531           if (Flags != 0)
2532             Record.push_back(Flags);
2533         }
2534         break;
2535       case Instruction::FNeg: {
2536         assert(CE->getNumOperands() == 1 && "Unknown constant expr!");
2537         Code = bitc::CST_CODE_CE_UNOP;
2538         Record.push_back(getEncodedUnaryOpcode(CE->getOpcode()));
2539         Record.push_back(VE.getValueID(C->getOperand(0)));
2540         uint64_t Flags = getOptimizationFlags(CE);
2541         if (Flags != 0)
2542           Record.push_back(Flags);
2543         break;
2544       }
2545       case Instruction::GetElementPtr: {
2546         Code = bitc::CST_CODE_CE_GEP;
2547         const auto *GO = cast<GEPOperator>(C);
2548         Record.push_back(VE.getTypeID(GO->getSourceElementType()));
2549         if (Optional<unsigned> Idx = GO->getInRangeIndex()) {
2550           Code = bitc::CST_CODE_CE_GEP_WITH_INRANGE_INDEX;
2551           Record.push_back((*Idx << 1) | GO->isInBounds());
2552         } else if (GO->isInBounds())
2553           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
2554         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
2555           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
2556           Record.push_back(VE.getValueID(C->getOperand(i)));
2557         }
2558         break;
2559       }
2560       case Instruction::Select:
2561         Code = bitc::CST_CODE_CE_SELECT;
2562         Record.push_back(VE.getValueID(C->getOperand(0)));
2563         Record.push_back(VE.getValueID(C->getOperand(1)));
2564         Record.push_back(VE.getValueID(C->getOperand(2)));
2565         break;
2566       case Instruction::ExtractElement:
2567         Code = bitc::CST_CODE_CE_EXTRACTELT;
2568         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2569         Record.push_back(VE.getValueID(C->getOperand(0)));
2570         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
2571         Record.push_back(VE.getValueID(C->getOperand(1)));
2572         break;
2573       case Instruction::InsertElement:
2574         Code = bitc::CST_CODE_CE_INSERTELT;
2575         Record.push_back(VE.getValueID(C->getOperand(0)));
2576         Record.push_back(VE.getValueID(C->getOperand(1)));
2577         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
2578         Record.push_back(VE.getValueID(C->getOperand(2)));
2579         break;
2580       case Instruction::ShuffleVector:
2581         // If the return type and argument types are the same, this is a
2582         // standard shufflevector instruction.  If the types are different,
2583         // then the shuffle is widening or truncating the input vectors, and
2584         // the argument type must also be encoded.
2585         if (C->getType() == C->getOperand(0)->getType()) {
2586           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
2587         } else {
2588           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
2589           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2590         }
2591         Record.push_back(VE.getValueID(C->getOperand(0)));
2592         Record.push_back(VE.getValueID(C->getOperand(1)));
2593         Record.push_back(VE.getValueID(CE->getShuffleMaskForBitcode()));
2594         break;
2595       case Instruction::ICmp:
2596       case Instruction::FCmp:
2597         Code = bitc::CST_CODE_CE_CMP;
2598         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2599         Record.push_back(VE.getValueID(C->getOperand(0)));
2600         Record.push_back(VE.getValueID(C->getOperand(1)));
2601         Record.push_back(CE->getPredicate());
2602         break;
2603       }
2604     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
2605       Code = bitc::CST_CODE_BLOCKADDRESS;
2606       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
2607       Record.push_back(VE.getValueID(BA->getFunction()));
2608       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
2609     } else {
2610 #ifndef NDEBUG
2611       C->dump();
2612 #endif
2613       llvm_unreachable("Unknown constant!");
2614     }
2615     Stream.EmitRecord(Code, Record, AbbrevToUse);
2616     Record.clear();
2617   }
2618 
2619   Stream.ExitBlock();
2620 }
2621 
2622 void ModuleBitcodeWriter::writeModuleConstants() {
2623   const ValueEnumerator::ValueList &Vals = VE.getValues();
2624 
2625   // Find the first constant to emit, which is the first non-globalvalue value.
2626   // We know globalvalues have been emitted by WriteModuleInfo.
2627   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
2628     if (!isa<GlobalValue>(Vals[i].first)) {
2629       writeConstants(i, Vals.size(), true);
2630       return;
2631     }
2632   }
2633 }
2634 
2635 /// pushValueAndType - The file has to encode both the value and type id for
2636 /// many values, because we need to know what type to create for forward
2637 /// references.  However, most operands are not forward references, so this type
2638 /// field is not needed.
2639 ///
2640 /// This function adds V's value ID to Vals.  If the value ID is higher than the
2641 /// instruction ID, then it is a forward reference, and it also includes the
2642 /// type ID.  The value ID that is written is encoded relative to the InstID.
2643 bool ModuleBitcodeWriter::pushValueAndType(const Value *V, unsigned InstID,
2644                                            SmallVectorImpl<unsigned> &Vals) {
2645   unsigned ValID = VE.getValueID(V);
2646   // Make encoding relative to the InstID.
2647   Vals.push_back(InstID - ValID);
2648   if (ValID >= InstID) {
2649     Vals.push_back(VE.getTypeID(V->getType()));
2650     return true;
2651   }
2652   return false;
2653 }
2654 
2655 void ModuleBitcodeWriter::writeOperandBundles(const CallBase &CS,
2656                                               unsigned InstID) {
2657   SmallVector<unsigned, 64> Record;
2658   LLVMContext &C = CS.getContext();
2659 
2660   for (unsigned i = 0, e = CS.getNumOperandBundles(); i != e; ++i) {
2661     const auto &Bundle = CS.getOperandBundleAt(i);
2662     Record.push_back(C.getOperandBundleTagID(Bundle.getTagName()));
2663 
2664     for (auto &Input : Bundle.Inputs)
2665       pushValueAndType(Input, InstID, Record);
2666 
2667     Stream.EmitRecord(bitc::FUNC_CODE_OPERAND_BUNDLE, Record);
2668     Record.clear();
2669   }
2670 }
2671 
2672 /// pushValue - Like pushValueAndType, but where the type of the value is
2673 /// omitted (perhaps it was already encoded in an earlier operand).
2674 void ModuleBitcodeWriter::pushValue(const Value *V, unsigned InstID,
2675                                     SmallVectorImpl<unsigned> &Vals) {
2676   unsigned ValID = VE.getValueID(V);
2677   Vals.push_back(InstID - ValID);
2678 }
2679 
2680 void ModuleBitcodeWriter::pushValueSigned(const Value *V, unsigned InstID,
2681                                           SmallVectorImpl<uint64_t> &Vals) {
2682   unsigned ValID = VE.getValueID(V);
2683   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
2684   emitSignedInt64(Vals, diff);
2685 }
2686 
2687 /// WriteInstruction - Emit an instruction to the specified stream.
2688 void ModuleBitcodeWriter::writeInstruction(const Instruction &I,
2689                                            unsigned InstID,
2690                                            SmallVectorImpl<unsigned> &Vals) {
2691   unsigned Code = 0;
2692   unsigned AbbrevToUse = 0;
2693   VE.setInstructionID(&I);
2694   switch (I.getOpcode()) {
2695   default:
2696     if (Instruction::isCast(I.getOpcode())) {
2697       Code = bitc::FUNC_CODE_INST_CAST;
2698       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2699         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
2700       Vals.push_back(VE.getTypeID(I.getType()));
2701       Vals.push_back(getEncodedCastOpcode(I.getOpcode()));
2702     } else {
2703       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
2704       Code = bitc::FUNC_CODE_INST_BINOP;
2705       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2706         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
2707       pushValue(I.getOperand(1), InstID, Vals);
2708       Vals.push_back(getEncodedBinaryOpcode(I.getOpcode()));
2709       uint64_t Flags = getOptimizationFlags(&I);
2710       if (Flags != 0) {
2711         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
2712           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
2713         Vals.push_back(Flags);
2714       }
2715     }
2716     break;
2717   case Instruction::FNeg: {
2718     Code = bitc::FUNC_CODE_INST_UNOP;
2719     if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2720       AbbrevToUse = FUNCTION_INST_UNOP_ABBREV;
2721     Vals.push_back(getEncodedUnaryOpcode(I.getOpcode()));
2722     uint64_t Flags = getOptimizationFlags(&I);
2723     if (Flags != 0) {
2724       if (AbbrevToUse == FUNCTION_INST_UNOP_ABBREV)
2725         AbbrevToUse = FUNCTION_INST_UNOP_FLAGS_ABBREV;
2726       Vals.push_back(Flags);
2727     }
2728     break;
2729   }
2730   case Instruction::GetElementPtr: {
2731     Code = bitc::FUNC_CODE_INST_GEP;
2732     AbbrevToUse = FUNCTION_INST_GEP_ABBREV;
2733     auto &GEPInst = cast<GetElementPtrInst>(I);
2734     Vals.push_back(GEPInst.isInBounds());
2735     Vals.push_back(VE.getTypeID(GEPInst.getSourceElementType()));
2736     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
2737       pushValueAndType(I.getOperand(i), InstID, Vals);
2738     break;
2739   }
2740   case Instruction::ExtractValue: {
2741     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
2742     pushValueAndType(I.getOperand(0), InstID, Vals);
2743     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
2744     Vals.append(EVI->idx_begin(), EVI->idx_end());
2745     break;
2746   }
2747   case Instruction::InsertValue: {
2748     Code = bitc::FUNC_CODE_INST_INSERTVAL;
2749     pushValueAndType(I.getOperand(0), InstID, Vals);
2750     pushValueAndType(I.getOperand(1), InstID, Vals);
2751     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
2752     Vals.append(IVI->idx_begin(), IVI->idx_end());
2753     break;
2754   }
2755   case Instruction::Select: {
2756     Code = bitc::FUNC_CODE_INST_VSELECT;
2757     pushValueAndType(I.getOperand(1), InstID, Vals);
2758     pushValue(I.getOperand(2), InstID, Vals);
2759     pushValueAndType(I.getOperand(0), InstID, Vals);
2760     uint64_t Flags = getOptimizationFlags(&I);
2761     if (Flags != 0)
2762       Vals.push_back(Flags);
2763     break;
2764   }
2765   case Instruction::ExtractElement:
2766     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
2767     pushValueAndType(I.getOperand(0), InstID, Vals);
2768     pushValueAndType(I.getOperand(1), InstID, Vals);
2769     break;
2770   case Instruction::InsertElement:
2771     Code = bitc::FUNC_CODE_INST_INSERTELT;
2772     pushValueAndType(I.getOperand(0), InstID, Vals);
2773     pushValue(I.getOperand(1), InstID, Vals);
2774     pushValueAndType(I.getOperand(2), InstID, Vals);
2775     break;
2776   case Instruction::ShuffleVector:
2777     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
2778     pushValueAndType(I.getOperand(0), InstID, Vals);
2779     pushValue(I.getOperand(1), InstID, Vals);
2780     pushValue(cast<ShuffleVectorInst>(I).getShuffleMaskForBitcode(), InstID,
2781               Vals);
2782     break;
2783   case Instruction::ICmp:
2784   case Instruction::FCmp: {
2785     // compare returning Int1Ty or vector of Int1Ty
2786     Code = bitc::FUNC_CODE_INST_CMP2;
2787     pushValueAndType(I.getOperand(0), InstID, Vals);
2788     pushValue(I.getOperand(1), InstID, Vals);
2789     Vals.push_back(cast<CmpInst>(I).getPredicate());
2790     uint64_t Flags = getOptimizationFlags(&I);
2791     if (Flags != 0)
2792       Vals.push_back(Flags);
2793     break;
2794   }
2795 
2796   case Instruction::Ret:
2797     {
2798       Code = bitc::FUNC_CODE_INST_RET;
2799       unsigned NumOperands = I.getNumOperands();
2800       if (NumOperands == 0)
2801         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
2802       else if (NumOperands == 1) {
2803         if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2804           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
2805       } else {
2806         for (unsigned i = 0, e = NumOperands; i != e; ++i)
2807           pushValueAndType(I.getOperand(i), InstID, Vals);
2808       }
2809     }
2810     break;
2811   case Instruction::Br:
2812     {
2813       Code = bitc::FUNC_CODE_INST_BR;
2814       const BranchInst &II = cast<BranchInst>(I);
2815       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
2816       if (II.isConditional()) {
2817         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
2818         pushValue(II.getCondition(), InstID, Vals);
2819       }
2820     }
2821     break;
2822   case Instruction::Switch:
2823     {
2824       Code = bitc::FUNC_CODE_INST_SWITCH;
2825       const SwitchInst &SI = cast<SwitchInst>(I);
2826       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
2827       pushValue(SI.getCondition(), InstID, Vals);
2828       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
2829       for (auto Case : SI.cases()) {
2830         Vals.push_back(VE.getValueID(Case.getCaseValue()));
2831         Vals.push_back(VE.getValueID(Case.getCaseSuccessor()));
2832       }
2833     }
2834     break;
2835   case Instruction::IndirectBr:
2836     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
2837     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2838     // Encode the address operand as relative, but not the basic blocks.
2839     pushValue(I.getOperand(0), InstID, Vals);
2840     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
2841       Vals.push_back(VE.getValueID(I.getOperand(i)));
2842     break;
2843 
2844   case Instruction::Invoke: {
2845     const InvokeInst *II = cast<InvokeInst>(&I);
2846     const Value *Callee = II->getCalledOperand();
2847     FunctionType *FTy = II->getFunctionType();
2848 
2849     if (II->hasOperandBundles())
2850       writeOperandBundles(*II, InstID);
2851 
2852     Code = bitc::FUNC_CODE_INST_INVOKE;
2853 
2854     Vals.push_back(VE.getAttributeListID(II->getAttributes()));
2855     Vals.push_back(II->getCallingConv() | 1 << 13);
2856     Vals.push_back(VE.getValueID(II->getNormalDest()));
2857     Vals.push_back(VE.getValueID(II->getUnwindDest()));
2858     Vals.push_back(VE.getTypeID(FTy));
2859     pushValueAndType(Callee, InstID, Vals);
2860 
2861     // Emit value #'s for the fixed parameters.
2862     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
2863       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
2864 
2865     // Emit type/value pairs for varargs params.
2866     if (FTy->isVarArg()) {
2867       for (unsigned i = FTy->getNumParams(), e = II->getNumArgOperands();
2868            i != e; ++i)
2869         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
2870     }
2871     break;
2872   }
2873   case Instruction::Resume:
2874     Code = bitc::FUNC_CODE_INST_RESUME;
2875     pushValueAndType(I.getOperand(0), InstID, Vals);
2876     break;
2877   case Instruction::CleanupRet: {
2878     Code = bitc::FUNC_CODE_INST_CLEANUPRET;
2879     const auto &CRI = cast<CleanupReturnInst>(I);
2880     pushValue(CRI.getCleanupPad(), InstID, Vals);
2881     if (CRI.hasUnwindDest())
2882       Vals.push_back(VE.getValueID(CRI.getUnwindDest()));
2883     break;
2884   }
2885   case Instruction::CatchRet: {
2886     Code = bitc::FUNC_CODE_INST_CATCHRET;
2887     const auto &CRI = cast<CatchReturnInst>(I);
2888     pushValue(CRI.getCatchPad(), InstID, Vals);
2889     Vals.push_back(VE.getValueID(CRI.getSuccessor()));
2890     break;
2891   }
2892   case Instruction::CleanupPad:
2893   case Instruction::CatchPad: {
2894     const auto &FuncletPad = cast<FuncletPadInst>(I);
2895     Code = isa<CatchPadInst>(FuncletPad) ? bitc::FUNC_CODE_INST_CATCHPAD
2896                                          : bitc::FUNC_CODE_INST_CLEANUPPAD;
2897     pushValue(FuncletPad.getParentPad(), InstID, Vals);
2898 
2899     unsigned NumArgOperands = FuncletPad.getNumArgOperands();
2900     Vals.push_back(NumArgOperands);
2901     for (unsigned Op = 0; Op != NumArgOperands; ++Op)
2902       pushValueAndType(FuncletPad.getArgOperand(Op), InstID, Vals);
2903     break;
2904   }
2905   case Instruction::CatchSwitch: {
2906     Code = bitc::FUNC_CODE_INST_CATCHSWITCH;
2907     const auto &CatchSwitch = cast<CatchSwitchInst>(I);
2908 
2909     pushValue(CatchSwitch.getParentPad(), InstID, Vals);
2910 
2911     unsigned NumHandlers = CatchSwitch.getNumHandlers();
2912     Vals.push_back(NumHandlers);
2913     for (const BasicBlock *CatchPadBB : CatchSwitch.handlers())
2914       Vals.push_back(VE.getValueID(CatchPadBB));
2915 
2916     if (CatchSwitch.hasUnwindDest())
2917       Vals.push_back(VE.getValueID(CatchSwitch.getUnwindDest()));
2918     break;
2919   }
2920   case Instruction::CallBr: {
2921     const CallBrInst *CBI = cast<CallBrInst>(&I);
2922     const Value *Callee = CBI->getCalledOperand();
2923     FunctionType *FTy = CBI->getFunctionType();
2924 
2925     if (CBI->hasOperandBundles())
2926       writeOperandBundles(*CBI, InstID);
2927 
2928     Code = bitc::FUNC_CODE_INST_CALLBR;
2929 
2930     Vals.push_back(VE.getAttributeListID(CBI->getAttributes()));
2931 
2932     Vals.push_back(CBI->getCallingConv() << bitc::CALL_CCONV |
2933                    1 << bitc::CALL_EXPLICIT_TYPE);
2934 
2935     Vals.push_back(VE.getValueID(CBI->getDefaultDest()));
2936     Vals.push_back(CBI->getNumIndirectDests());
2937     for (unsigned i = 0, e = CBI->getNumIndirectDests(); i != e; ++i)
2938       Vals.push_back(VE.getValueID(CBI->getIndirectDest(i)));
2939 
2940     Vals.push_back(VE.getTypeID(FTy));
2941     pushValueAndType(Callee, InstID, Vals);
2942 
2943     // Emit value #'s for the fixed parameters.
2944     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
2945       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
2946 
2947     // Emit type/value pairs for varargs params.
2948     if (FTy->isVarArg()) {
2949       for (unsigned i = FTy->getNumParams(), e = CBI->getNumArgOperands();
2950            i != e; ++i)
2951         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
2952     }
2953     break;
2954   }
2955   case Instruction::Unreachable:
2956     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
2957     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
2958     break;
2959 
2960   case Instruction::PHI: {
2961     const PHINode &PN = cast<PHINode>(I);
2962     Code = bitc::FUNC_CODE_INST_PHI;
2963     // With the newer instruction encoding, forward references could give
2964     // negative valued IDs.  This is most common for PHIs, so we use
2965     // signed VBRs.
2966     SmallVector<uint64_t, 128> Vals64;
2967     Vals64.push_back(VE.getTypeID(PN.getType()));
2968     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
2969       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64);
2970       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
2971     }
2972 
2973     uint64_t Flags = getOptimizationFlags(&I);
2974     if (Flags != 0)
2975       Vals64.push_back(Flags);
2976 
2977     // Emit a Vals64 vector and exit.
2978     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
2979     Vals64.clear();
2980     return;
2981   }
2982 
2983   case Instruction::LandingPad: {
2984     const LandingPadInst &LP = cast<LandingPadInst>(I);
2985     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
2986     Vals.push_back(VE.getTypeID(LP.getType()));
2987     Vals.push_back(LP.isCleanup());
2988     Vals.push_back(LP.getNumClauses());
2989     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
2990       if (LP.isCatch(I))
2991         Vals.push_back(LandingPadInst::Catch);
2992       else
2993         Vals.push_back(LandingPadInst::Filter);
2994       pushValueAndType(LP.getClause(I), InstID, Vals);
2995     }
2996     break;
2997   }
2998 
2999   case Instruction::Alloca: {
3000     Code = bitc::FUNC_CODE_INST_ALLOCA;
3001     const AllocaInst &AI = cast<AllocaInst>(I);
3002     Vals.push_back(VE.getTypeID(AI.getAllocatedType()));
3003     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
3004     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
3005     using APV = AllocaPackedValues;
3006     unsigned Record = 0;
3007     Bitfield::set<APV::Align>(Record, getEncodedAlign(AI.getAlign()));
3008     Bitfield::set<APV::UsedWithInAlloca>(Record, AI.isUsedWithInAlloca());
3009     Bitfield::set<APV::ExplicitType>(Record, true);
3010     Bitfield::set<APV::SwiftError>(Record, AI.isSwiftError());
3011     Vals.push_back(Record);
3012     break;
3013   }
3014 
3015   case Instruction::Load:
3016     if (cast<LoadInst>(I).isAtomic()) {
3017       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
3018       pushValueAndType(I.getOperand(0), InstID, Vals);
3019     } else {
3020       Code = bitc::FUNC_CODE_INST_LOAD;
3021       if (!pushValueAndType(I.getOperand(0), InstID, Vals)) // ptr
3022         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
3023     }
3024     Vals.push_back(VE.getTypeID(I.getType()));
3025     Vals.push_back(getEncodedAlign(cast<LoadInst>(I).getAlign()));
3026     Vals.push_back(cast<LoadInst>(I).isVolatile());
3027     if (cast<LoadInst>(I).isAtomic()) {
3028       Vals.push_back(getEncodedOrdering(cast<LoadInst>(I).getOrdering()));
3029       Vals.push_back(getEncodedSyncScopeID(cast<LoadInst>(I).getSyncScopeID()));
3030     }
3031     break;
3032   case Instruction::Store:
3033     if (cast<StoreInst>(I).isAtomic())
3034       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
3035     else
3036       Code = bitc::FUNC_CODE_INST_STORE;
3037     pushValueAndType(I.getOperand(1), InstID, Vals); // ptrty + ptr
3038     pushValueAndType(I.getOperand(0), InstID, Vals); // valty + val
3039     Vals.push_back(getEncodedAlign(cast<StoreInst>(I).getAlign()));
3040     Vals.push_back(cast<StoreInst>(I).isVolatile());
3041     if (cast<StoreInst>(I).isAtomic()) {
3042       Vals.push_back(getEncodedOrdering(cast<StoreInst>(I).getOrdering()));
3043       Vals.push_back(
3044           getEncodedSyncScopeID(cast<StoreInst>(I).getSyncScopeID()));
3045     }
3046     break;
3047   case Instruction::AtomicCmpXchg:
3048     Code = bitc::FUNC_CODE_INST_CMPXCHG;
3049     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
3050     pushValueAndType(I.getOperand(1), InstID, Vals); // cmp.
3051     pushValue(I.getOperand(2), InstID, Vals);        // newval.
3052     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
3053     Vals.push_back(
3054         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
3055     Vals.push_back(
3056         getEncodedSyncScopeID(cast<AtomicCmpXchgInst>(I).getSyncScopeID()));
3057     Vals.push_back(
3058         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
3059     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
3060     break;
3061   case Instruction::AtomicRMW:
3062     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
3063     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
3064     pushValue(I.getOperand(1), InstID, Vals);        // val.
3065     Vals.push_back(
3066         getEncodedRMWOperation(cast<AtomicRMWInst>(I).getOperation()));
3067     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
3068     Vals.push_back(getEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
3069     Vals.push_back(
3070         getEncodedSyncScopeID(cast<AtomicRMWInst>(I).getSyncScopeID()));
3071     break;
3072   case Instruction::Fence:
3073     Code = bitc::FUNC_CODE_INST_FENCE;
3074     Vals.push_back(getEncodedOrdering(cast<FenceInst>(I).getOrdering()));
3075     Vals.push_back(getEncodedSyncScopeID(cast<FenceInst>(I).getSyncScopeID()));
3076     break;
3077   case Instruction::Call: {
3078     const CallInst &CI = cast<CallInst>(I);
3079     FunctionType *FTy = CI.getFunctionType();
3080 
3081     if (CI.hasOperandBundles())
3082       writeOperandBundles(CI, InstID);
3083 
3084     Code = bitc::FUNC_CODE_INST_CALL;
3085 
3086     Vals.push_back(VE.getAttributeListID(CI.getAttributes()));
3087 
3088     unsigned Flags = getOptimizationFlags(&I);
3089     Vals.push_back(CI.getCallingConv() << bitc::CALL_CCONV |
3090                    unsigned(CI.isTailCall()) << bitc::CALL_TAIL |
3091                    unsigned(CI.isMustTailCall()) << bitc::CALL_MUSTTAIL |
3092                    1 << bitc::CALL_EXPLICIT_TYPE |
3093                    unsigned(CI.isNoTailCall()) << bitc::CALL_NOTAIL |
3094                    unsigned(Flags != 0) << bitc::CALL_FMF);
3095     if (Flags != 0)
3096       Vals.push_back(Flags);
3097 
3098     Vals.push_back(VE.getTypeID(FTy));
3099     pushValueAndType(CI.getCalledOperand(), InstID, Vals); // Callee
3100 
3101     // Emit value #'s for the fixed parameters.
3102     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
3103       // Check for labels (can happen with asm labels).
3104       if (FTy->getParamType(i)->isLabelTy())
3105         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
3106       else
3107         pushValue(CI.getArgOperand(i), InstID, Vals); // fixed param.
3108     }
3109 
3110     // Emit type/value pairs for varargs params.
3111     if (FTy->isVarArg()) {
3112       for (unsigned i = FTy->getNumParams(), e = CI.getNumArgOperands();
3113            i != e; ++i)
3114         pushValueAndType(CI.getArgOperand(i), InstID, Vals); // varargs
3115     }
3116     break;
3117   }
3118   case Instruction::VAArg:
3119     Code = bitc::FUNC_CODE_INST_VAARG;
3120     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
3121     pushValue(I.getOperand(0), InstID, Vals);                   // valist.
3122     Vals.push_back(VE.getTypeID(I.getType())); // restype.
3123     break;
3124   case Instruction::Freeze:
3125     Code = bitc::FUNC_CODE_INST_FREEZE;
3126     pushValueAndType(I.getOperand(0), InstID, Vals);
3127     break;
3128   }
3129 
3130   Stream.EmitRecord(Code, Vals, AbbrevToUse);
3131   Vals.clear();
3132 }
3133 
3134 /// Write a GlobalValue VST to the module. The purpose of this data structure is
3135 /// to allow clients to efficiently find the function body.
3136 void ModuleBitcodeWriter::writeGlobalValueSymbolTable(
3137   DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3138   // Get the offset of the VST we are writing, and backpatch it into
3139   // the VST forward declaration record.
3140   uint64_t VSTOffset = Stream.GetCurrentBitNo();
3141   // The BitcodeStartBit was the stream offset of the identification block.
3142   VSTOffset -= bitcodeStartBit();
3143   assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
3144   // Note that we add 1 here because the offset is relative to one word
3145   // before the start of the identification block, which was historically
3146   // always the start of the regular bitcode header.
3147   Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32 + 1);
3148 
3149   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3150 
3151   auto Abbv = std::make_shared<BitCodeAbbrev>();
3152   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
3153   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
3154   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
3155   unsigned FnEntryAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3156 
3157   for (const Function &F : M) {
3158     uint64_t Record[2];
3159 
3160     if (F.isDeclaration())
3161       continue;
3162 
3163     Record[0] = VE.getValueID(&F);
3164 
3165     // Save the word offset of the function (from the start of the
3166     // actual bitcode written to the stream).
3167     uint64_t BitcodeIndex = FunctionToBitcodeIndex[&F] - bitcodeStartBit();
3168     assert((BitcodeIndex & 31) == 0 && "function block not 32-bit aligned");
3169     // Note that we add 1 here because the offset is relative to one word
3170     // before the start of the identification block, which was historically
3171     // always the start of the regular bitcode header.
3172     Record[1] = BitcodeIndex / 32 + 1;
3173 
3174     Stream.EmitRecord(bitc::VST_CODE_FNENTRY, Record, FnEntryAbbrev);
3175   }
3176 
3177   Stream.ExitBlock();
3178 }
3179 
3180 /// Emit names for arguments, instructions and basic blocks in a function.
3181 void ModuleBitcodeWriter::writeFunctionLevelValueSymbolTable(
3182     const ValueSymbolTable &VST) {
3183   if (VST.empty())
3184     return;
3185 
3186   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3187 
3188   // FIXME: Set up the abbrev, we know how many values there are!
3189   // FIXME: We know if the type names can use 7-bit ascii.
3190   SmallVector<uint64_t, 64> NameVals;
3191 
3192   for (const ValueName &Name : VST) {
3193     // Figure out the encoding to use for the name.
3194     StringEncoding Bits = getStringEncoding(Name.getKey());
3195 
3196     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
3197     NameVals.push_back(VE.getValueID(Name.getValue()));
3198 
3199     // VST_CODE_ENTRY:   [valueid, namechar x N]
3200     // VST_CODE_BBENTRY: [bbid, namechar x N]
3201     unsigned Code;
3202     if (isa<BasicBlock>(Name.getValue())) {
3203       Code = bitc::VST_CODE_BBENTRY;
3204       if (Bits == SE_Char6)
3205         AbbrevToUse = VST_BBENTRY_6_ABBREV;
3206     } else {
3207       Code = bitc::VST_CODE_ENTRY;
3208       if (Bits == SE_Char6)
3209         AbbrevToUse = VST_ENTRY_6_ABBREV;
3210       else if (Bits == SE_Fixed7)
3211         AbbrevToUse = VST_ENTRY_7_ABBREV;
3212     }
3213 
3214     for (const auto P : Name.getKey())
3215       NameVals.push_back((unsigned char)P);
3216 
3217     // Emit the finished record.
3218     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
3219     NameVals.clear();
3220   }
3221 
3222   Stream.ExitBlock();
3223 }
3224 
3225 void ModuleBitcodeWriter::writeUseList(UseListOrder &&Order) {
3226   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
3227   unsigned Code;
3228   if (isa<BasicBlock>(Order.V))
3229     Code = bitc::USELIST_CODE_BB;
3230   else
3231     Code = bitc::USELIST_CODE_DEFAULT;
3232 
3233   SmallVector<uint64_t, 64> Record(Order.Shuffle.begin(), Order.Shuffle.end());
3234   Record.push_back(VE.getValueID(Order.V));
3235   Stream.EmitRecord(Code, Record);
3236 }
3237 
3238 void ModuleBitcodeWriter::writeUseListBlock(const Function *F) {
3239   assert(VE.shouldPreserveUseListOrder() &&
3240          "Expected to be preserving use-list order");
3241 
3242   auto hasMore = [&]() {
3243     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
3244   };
3245   if (!hasMore())
3246     // Nothing to do.
3247     return;
3248 
3249   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
3250   while (hasMore()) {
3251     writeUseList(std::move(VE.UseListOrders.back()));
3252     VE.UseListOrders.pop_back();
3253   }
3254   Stream.ExitBlock();
3255 }
3256 
3257 /// Emit a function body to the module stream.
3258 void ModuleBitcodeWriter::writeFunction(
3259     const Function &F,
3260     DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3261   // Save the bitcode index of the start of this function block for recording
3262   // in the VST.
3263   FunctionToBitcodeIndex[&F] = Stream.GetCurrentBitNo();
3264 
3265   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
3266   VE.incorporateFunction(F);
3267 
3268   SmallVector<unsigned, 64> Vals;
3269 
3270   // Emit the number of basic blocks, so the reader can create them ahead of
3271   // time.
3272   Vals.push_back(VE.getBasicBlocks().size());
3273   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
3274   Vals.clear();
3275 
3276   // If there are function-local constants, emit them now.
3277   unsigned CstStart, CstEnd;
3278   VE.getFunctionConstantRange(CstStart, CstEnd);
3279   writeConstants(CstStart, CstEnd, false);
3280 
3281   // If there is function-local metadata, emit it now.
3282   writeFunctionMetadata(F);
3283 
3284   // Keep a running idea of what the instruction ID is.
3285   unsigned InstID = CstEnd;
3286 
3287   bool NeedsMetadataAttachment = F.hasMetadata();
3288 
3289   DILocation *LastDL = nullptr;
3290   // Finally, emit all the instructions, in order.
3291   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
3292     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
3293          I != E; ++I) {
3294       writeInstruction(*I, InstID, Vals);
3295 
3296       if (!I->getType()->isVoidTy())
3297         ++InstID;
3298 
3299       // If the instruction has metadata, write a metadata attachment later.
3300       NeedsMetadataAttachment |= I->hasMetadataOtherThanDebugLoc();
3301 
3302       // If the instruction has a debug location, emit it.
3303       DILocation *DL = I->getDebugLoc();
3304       if (!DL)
3305         continue;
3306 
3307       if (DL == LastDL) {
3308         // Just repeat the same debug loc as last time.
3309         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
3310         continue;
3311       }
3312 
3313       Vals.push_back(DL->getLine());
3314       Vals.push_back(DL->getColumn());
3315       Vals.push_back(VE.getMetadataOrNullID(DL->getScope()));
3316       Vals.push_back(VE.getMetadataOrNullID(DL->getInlinedAt()));
3317       Vals.push_back(DL->isImplicitCode());
3318       Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
3319       Vals.clear();
3320 
3321       LastDL = DL;
3322     }
3323 
3324   // Emit names for all the instructions etc.
3325   if (auto *Symtab = F.getValueSymbolTable())
3326     writeFunctionLevelValueSymbolTable(*Symtab);
3327 
3328   if (NeedsMetadataAttachment)
3329     writeFunctionMetadataAttachment(F);
3330   if (VE.shouldPreserveUseListOrder())
3331     writeUseListBlock(&F);
3332   VE.purgeFunction();
3333   Stream.ExitBlock();
3334 }
3335 
3336 // Emit blockinfo, which defines the standard abbreviations etc.
3337 void ModuleBitcodeWriter::writeBlockInfo() {
3338   // We only want to emit block info records for blocks that have multiple
3339   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
3340   // Other blocks can define their abbrevs inline.
3341   Stream.EnterBlockInfoBlock();
3342 
3343   { // 8-bit fixed-width VST_CODE_ENTRY/VST_CODE_BBENTRY strings.
3344     auto Abbv = std::make_shared<BitCodeAbbrev>();
3345     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
3346     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3347     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3348     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3349     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3350         VST_ENTRY_8_ABBREV)
3351       llvm_unreachable("Unexpected abbrev ordering!");
3352   }
3353 
3354   { // 7-bit fixed width VST_CODE_ENTRY strings.
3355     auto Abbv = std::make_shared<BitCodeAbbrev>();
3356     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3357     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3358     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3359     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3360     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3361         VST_ENTRY_7_ABBREV)
3362       llvm_unreachable("Unexpected abbrev ordering!");
3363   }
3364   { // 6-bit char6 VST_CODE_ENTRY strings.
3365     auto Abbv = std::make_shared<BitCodeAbbrev>();
3366     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3367     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3368     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3369     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3370     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3371         VST_ENTRY_6_ABBREV)
3372       llvm_unreachable("Unexpected abbrev ordering!");
3373   }
3374   { // 6-bit char6 VST_CODE_BBENTRY strings.
3375     auto Abbv = std::make_shared<BitCodeAbbrev>();
3376     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
3377     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3378     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3379     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3380     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3381         VST_BBENTRY_6_ABBREV)
3382       llvm_unreachable("Unexpected abbrev ordering!");
3383   }
3384 
3385   { // SETTYPE abbrev for CONSTANTS_BLOCK.
3386     auto Abbv = std::make_shared<BitCodeAbbrev>();
3387     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
3388     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
3389                               VE.computeBitsRequiredForTypeIndicies()));
3390     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3391         CONSTANTS_SETTYPE_ABBREV)
3392       llvm_unreachable("Unexpected abbrev ordering!");
3393   }
3394 
3395   { // INTEGER abbrev for CONSTANTS_BLOCK.
3396     auto Abbv = std::make_shared<BitCodeAbbrev>();
3397     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
3398     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3399     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3400         CONSTANTS_INTEGER_ABBREV)
3401       llvm_unreachable("Unexpected abbrev ordering!");
3402   }
3403 
3404   { // CE_CAST abbrev for CONSTANTS_BLOCK.
3405     auto Abbv = std::make_shared<BitCodeAbbrev>();
3406     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
3407     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
3408     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
3409                               VE.computeBitsRequiredForTypeIndicies()));
3410     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
3411 
3412     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3413         CONSTANTS_CE_CAST_Abbrev)
3414       llvm_unreachable("Unexpected abbrev ordering!");
3415   }
3416   { // NULL abbrev for CONSTANTS_BLOCK.
3417     auto Abbv = std::make_shared<BitCodeAbbrev>();
3418     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
3419     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3420         CONSTANTS_NULL_Abbrev)
3421       llvm_unreachable("Unexpected abbrev ordering!");
3422   }
3423 
3424   // FIXME: This should only use space for first class types!
3425 
3426   { // INST_LOAD abbrev for FUNCTION_BLOCK.
3427     auto Abbv = std::make_shared<BitCodeAbbrev>();
3428     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
3429     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
3430     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
3431                               VE.computeBitsRequiredForTypeIndicies()));
3432     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
3433     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
3434     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3435         FUNCTION_INST_LOAD_ABBREV)
3436       llvm_unreachable("Unexpected abbrev ordering!");
3437   }
3438   { // INST_UNOP abbrev for FUNCTION_BLOCK.
3439     auto Abbv = std::make_shared<BitCodeAbbrev>();
3440     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3441     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3442     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3443     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3444         FUNCTION_INST_UNOP_ABBREV)
3445       llvm_unreachable("Unexpected abbrev ordering!");
3446   }
3447   { // INST_UNOP_FLAGS abbrev for FUNCTION_BLOCK.
3448     auto Abbv = std::make_shared<BitCodeAbbrev>();
3449     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3450     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3451     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3452     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3453     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3454         FUNCTION_INST_UNOP_FLAGS_ABBREV)
3455       llvm_unreachable("Unexpected abbrev ordering!");
3456   }
3457   { // INST_BINOP abbrev for FUNCTION_BLOCK.
3458     auto Abbv = std::make_shared<BitCodeAbbrev>();
3459     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3460     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3461     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3462     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3463     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3464         FUNCTION_INST_BINOP_ABBREV)
3465       llvm_unreachable("Unexpected abbrev ordering!");
3466   }
3467   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
3468     auto Abbv = std::make_shared<BitCodeAbbrev>();
3469     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3470     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3471     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3472     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3473     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3474     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3475         FUNCTION_INST_BINOP_FLAGS_ABBREV)
3476       llvm_unreachable("Unexpected abbrev ordering!");
3477   }
3478   { // INST_CAST abbrev for FUNCTION_BLOCK.
3479     auto Abbv = std::make_shared<BitCodeAbbrev>();
3480     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
3481     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
3482     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
3483                               VE.computeBitsRequiredForTypeIndicies()));
3484     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
3485     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3486         FUNCTION_INST_CAST_ABBREV)
3487       llvm_unreachable("Unexpected abbrev ordering!");
3488   }
3489 
3490   { // INST_RET abbrev for FUNCTION_BLOCK.
3491     auto Abbv = std::make_shared<BitCodeAbbrev>();
3492     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3493     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3494         FUNCTION_INST_RET_VOID_ABBREV)
3495       llvm_unreachable("Unexpected abbrev ordering!");
3496   }
3497   { // INST_RET abbrev for FUNCTION_BLOCK.
3498     auto Abbv = std::make_shared<BitCodeAbbrev>();
3499     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3500     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
3501     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3502         FUNCTION_INST_RET_VAL_ABBREV)
3503       llvm_unreachable("Unexpected abbrev ordering!");
3504   }
3505   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
3506     auto Abbv = std::make_shared<BitCodeAbbrev>();
3507     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
3508     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3509         FUNCTION_INST_UNREACHABLE_ABBREV)
3510       llvm_unreachable("Unexpected abbrev ordering!");
3511   }
3512   {
3513     auto Abbv = std::make_shared<BitCodeAbbrev>();
3514     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_GEP));
3515     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
3516     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, // dest ty
3517                               Log2_32_Ceil(VE.getTypes().size() + 1)));
3518     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3519     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
3520     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3521         FUNCTION_INST_GEP_ABBREV)
3522       llvm_unreachable("Unexpected abbrev ordering!");
3523   }
3524 
3525   Stream.ExitBlock();
3526 }
3527 
3528 /// Write the module path strings, currently only used when generating
3529 /// a combined index file.
3530 void IndexBitcodeWriter::writeModStrings() {
3531   Stream.EnterSubblock(bitc::MODULE_STRTAB_BLOCK_ID, 3);
3532 
3533   // TODO: See which abbrev sizes we actually need to emit
3534 
3535   // 8-bit fixed-width MST_ENTRY strings.
3536   auto Abbv = std::make_shared<BitCodeAbbrev>();
3537   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3538   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3539   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3540   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3541   unsigned Abbrev8Bit = Stream.EmitAbbrev(std::move(Abbv));
3542 
3543   // 7-bit fixed width MST_ENTRY strings.
3544   Abbv = std::make_shared<BitCodeAbbrev>();
3545   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3546   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3547   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3548   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3549   unsigned Abbrev7Bit = Stream.EmitAbbrev(std::move(Abbv));
3550 
3551   // 6-bit char6 MST_ENTRY strings.
3552   Abbv = std::make_shared<BitCodeAbbrev>();
3553   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3554   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3555   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3556   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3557   unsigned Abbrev6Bit = Stream.EmitAbbrev(std::move(Abbv));
3558 
3559   // Module Hash, 160 bits SHA1. Optionally, emitted after each MST_CODE_ENTRY.
3560   Abbv = std::make_shared<BitCodeAbbrev>();
3561   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_HASH));
3562   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3563   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3564   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3565   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3566   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3567   unsigned AbbrevHash = Stream.EmitAbbrev(std::move(Abbv));
3568 
3569   SmallVector<unsigned, 64> Vals;
3570   forEachModule(
3571       [&](const StringMapEntry<std::pair<uint64_t, ModuleHash>> &MPSE) {
3572         StringRef Key = MPSE.getKey();
3573         const auto &Value = MPSE.getValue();
3574         StringEncoding Bits = getStringEncoding(Key);
3575         unsigned AbbrevToUse = Abbrev8Bit;
3576         if (Bits == SE_Char6)
3577           AbbrevToUse = Abbrev6Bit;
3578         else if (Bits == SE_Fixed7)
3579           AbbrevToUse = Abbrev7Bit;
3580 
3581         Vals.push_back(Value.first);
3582         Vals.append(Key.begin(), Key.end());
3583 
3584         // Emit the finished record.
3585         Stream.EmitRecord(bitc::MST_CODE_ENTRY, Vals, AbbrevToUse);
3586 
3587         // Emit an optional hash for the module now
3588         const auto &Hash = Value.second;
3589         if (llvm::any_of(Hash, [](uint32_t H) { return H; })) {
3590           Vals.assign(Hash.begin(), Hash.end());
3591           // Emit the hash record.
3592           Stream.EmitRecord(bitc::MST_CODE_HASH, Vals, AbbrevHash);
3593         }
3594 
3595         Vals.clear();
3596       });
3597   Stream.ExitBlock();
3598 }
3599 
3600 /// Write the function type metadata related records that need to appear before
3601 /// a function summary entry (whether per-module or combined).
3602 template <typename Fn>
3603 static void writeFunctionTypeMetadataRecords(BitstreamWriter &Stream,
3604                                              FunctionSummary *FS,
3605                                              Fn GetValueID) {
3606   if (!FS->type_tests().empty())
3607     Stream.EmitRecord(bitc::FS_TYPE_TESTS, FS->type_tests());
3608 
3609   SmallVector<uint64_t, 64> Record;
3610 
3611   auto WriteVFuncIdVec = [&](uint64_t Ty,
3612                              ArrayRef<FunctionSummary::VFuncId> VFs) {
3613     if (VFs.empty())
3614       return;
3615     Record.clear();
3616     for (auto &VF : VFs) {
3617       Record.push_back(VF.GUID);
3618       Record.push_back(VF.Offset);
3619     }
3620     Stream.EmitRecord(Ty, Record);
3621   };
3622 
3623   WriteVFuncIdVec(bitc::FS_TYPE_TEST_ASSUME_VCALLS,
3624                   FS->type_test_assume_vcalls());
3625   WriteVFuncIdVec(bitc::FS_TYPE_CHECKED_LOAD_VCALLS,
3626                   FS->type_checked_load_vcalls());
3627 
3628   auto WriteConstVCallVec = [&](uint64_t Ty,
3629                                 ArrayRef<FunctionSummary::ConstVCall> VCs) {
3630     for (auto &VC : VCs) {
3631       Record.clear();
3632       Record.push_back(VC.VFunc.GUID);
3633       Record.push_back(VC.VFunc.Offset);
3634       llvm::append_range(Record, VC.Args);
3635       Stream.EmitRecord(Ty, Record);
3636     }
3637   };
3638 
3639   WriteConstVCallVec(bitc::FS_TYPE_TEST_ASSUME_CONST_VCALL,
3640                      FS->type_test_assume_const_vcalls());
3641   WriteConstVCallVec(bitc::FS_TYPE_CHECKED_LOAD_CONST_VCALL,
3642                      FS->type_checked_load_const_vcalls());
3643 
3644   auto WriteRange = [&](ConstantRange Range) {
3645     Range = Range.sextOrTrunc(FunctionSummary::ParamAccess::RangeWidth);
3646     assert(Range.getLower().getNumWords() == 1);
3647     assert(Range.getUpper().getNumWords() == 1);
3648     emitSignedInt64(Record, *Range.getLower().getRawData());
3649     emitSignedInt64(Record, *Range.getUpper().getRawData());
3650   };
3651 
3652   if (!FS->paramAccesses().empty()) {
3653     Record.clear();
3654     for (auto &Arg : FS->paramAccesses()) {
3655       size_t UndoSize = Record.size();
3656       Record.push_back(Arg.ParamNo);
3657       WriteRange(Arg.Use);
3658       Record.push_back(Arg.Calls.size());
3659       for (auto &Call : Arg.Calls) {
3660         Record.push_back(Call.ParamNo);
3661         Optional<unsigned> ValueID = GetValueID(Call.Callee);
3662         if (!ValueID) {
3663           // If ValueID is unknown we can't drop just this call, we must drop
3664           // entire parameter.
3665           Record.resize(UndoSize);
3666           break;
3667         }
3668         Record.push_back(*ValueID);
3669         WriteRange(Call.Offsets);
3670       }
3671     }
3672     if (!Record.empty())
3673       Stream.EmitRecord(bitc::FS_PARAM_ACCESS, Record);
3674   }
3675 }
3676 
3677 /// Collect type IDs from type tests used by function.
3678 static void
3679 getReferencedTypeIds(FunctionSummary *FS,
3680                      std::set<GlobalValue::GUID> &ReferencedTypeIds) {
3681   if (!FS->type_tests().empty())
3682     for (auto &TT : FS->type_tests())
3683       ReferencedTypeIds.insert(TT);
3684 
3685   auto GetReferencedTypesFromVFuncIdVec =
3686       [&](ArrayRef<FunctionSummary::VFuncId> VFs) {
3687         for (auto &VF : VFs)
3688           ReferencedTypeIds.insert(VF.GUID);
3689       };
3690 
3691   GetReferencedTypesFromVFuncIdVec(FS->type_test_assume_vcalls());
3692   GetReferencedTypesFromVFuncIdVec(FS->type_checked_load_vcalls());
3693 
3694   auto GetReferencedTypesFromConstVCallVec =
3695       [&](ArrayRef<FunctionSummary::ConstVCall> VCs) {
3696         for (auto &VC : VCs)
3697           ReferencedTypeIds.insert(VC.VFunc.GUID);
3698       };
3699 
3700   GetReferencedTypesFromConstVCallVec(FS->type_test_assume_const_vcalls());
3701   GetReferencedTypesFromConstVCallVec(FS->type_checked_load_const_vcalls());
3702 }
3703 
3704 static void writeWholeProgramDevirtResolutionByArg(
3705     SmallVector<uint64_t, 64> &NameVals, const std::vector<uint64_t> &args,
3706     const WholeProgramDevirtResolution::ByArg &ByArg) {
3707   NameVals.push_back(args.size());
3708   llvm::append_range(NameVals, args);
3709 
3710   NameVals.push_back(ByArg.TheKind);
3711   NameVals.push_back(ByArg.Info);
3712   NameVals.push_back(ByArg.Byte);
3713   NameVals.push_back(ByArg.Bit);
3714 }
3715 
3716 static void writeWholeProgramDevirtResolution(
3717     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3718     uint64_t Id, const WholeProgramDevirtResolution &Wpd) {
3719   NameVals.push_back(Id);
3720 
3721   NameVals.push_back(Wpd.TheKind);
3722   NameVals.push_back(StrtabBuilder.add(Wpd.SingleImplName));
3723   NameVals.push_back(Wpd.SingleImplName.size());
3724 
3725   NameVals.push_back(Wpd.ResByArg.size());
3726   for (auto &A : Wpd.ResByArg)
3727     writeWholeProgramDevirtResolutionByArg(NameVals, A.first, A.second);
3728 }
3729 
3730 static void writeTypeIdSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
3731                                      StringTableBuilder &StrtabBuilder,
3732                                      const std::string &Id,
3733                                      const TypeIdSummary &Summary) {
3734   NameVals.push_back(StrtabBuilder.add(Id));
3735   NameVals.push_back(Id.size());
3736 
3737   NameVals.push_back(Summary.TTRes.TheKind);
3738   NameVals.push_back(Summary.TTRes.SizeM1BitWidth);
3739   NameVals.push_back(Summary.TTRes.AlignLog2);
3740   NameVals.push_back(Summary.TTRes.SizeM1);
3741   NameVals.push_back(Summary.TTRes.BitMask);
3742   NameVals.push_back(Summary.TTRes.InlineBits);
3743 
3744   for (auto &W : Summary.WPDRes)
3745     writeWholeProgramDevirtResolution(NameVals, StrtabBuilder, W.first,
3746                                       W.second);
3747 }
3748 
3749 static void writeTypeIdCompatibleVtableSummaryRecord(
3750     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3751     const std::string &Id, const TypeIdCompatibleVtableInfo &Summary,
3752     ValueEnumerator &VE) {
3753   NameVals.push_back(StrtabBuilder.add(Id));
3754   NameVals.push_back(Id.size());
3755 
3756   for (auto &P : Summary) {
3757     NameVals.push_back(P.AddressPointOffset);
3758     NameVals.push_back(VE.getValueID(P.VTableVI.getValue()));
3759   }
3760 }
3761 
3762 // Helper to emit a single function summary record.
3763 void ModuleBitcodeWriterBase::writePerModuleFunctionSummaryRecord(
3764     SmallVector<uint64_t, 64> &NameVals, GlobalValueSummary *Summary,
3765     unsigned ValueID, unsigned FSCallsAbbrev, unsigned FSCallsProfileAbbrev,
3766     const Function &F) {
3767   NameVals.push_back(ValueID);
3768 
3769   FunctionSummary *FS = cast<FunctionSummary>(Summary);
3770 
3771   writeFunctionTypeMetadataRecords(
3772       Stream, FS, [&](const ValueInfo &VI) -> Optional<unsigned> {
3773         return {VE.getValueID(VI.getValue())};
3774       });
3775 
3776   auto SpecialRefCnts = FS->specialRefCounts();
3777   NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
3778   NameVals.push_back(FS->instCount());
3779   NameVals.push_back(getEncodedFFlags(FS->fflags()));
3780   NameVals.push_back(FS->refs().size());
3781   NameVals.push_back(SpecialRefCnts.first);  // rorefcnt
3782   NameVals.push_back(SpecialRefCnts.second); // worefcnt
3783 
3784   for (auto &RI : FS->refs())
3785     NameVals.push_back(VE.getValueID(RI.getValue()));
3786 
3787   bool HasProfileData =
3788       F.hasProfileData() || ForceSummaryEdgesCold != FunctionSummary::FSHT_None;
3789   for (auto &ECI : FS->calls()) {
3790     NameVals.push_back(getValueId(ECI.first));
3791     if (HasProfileData)
3792       NameVals.push_back(static_cast<uint8_t>(ECI.second.Hotness));
3793     else if (WriteRelBFToSummary)
3794       NameVals.push_back(ECI.second.RelBlockFreq);
3795   }
3796 
3797   unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
3798   unsigned Code =
3799       (HasProfileData ? bitc::FS_PERMODULE_PROFILE
3800                       : (WriteRelBFToSummary ? bitc::FS_PERMODULE_RELBF
3801                                              : bitc::FS_PERMODULE));
3802 
3803   // Emit the finished record.
3804   Stream.EmitRecord(Code, NameVals, FSAbbrev);
3805   NameVals.clear();
3806 }
3807 
3808 // Collect the global value references in the given variable's initializer,
3809 // and emit them in a summary record.
3810 void ModuleBitcodeWriterBase::writeModuleLevelReferences(
3811     const GlobalVariable &V, SmallVector<uint64_t, 64> &NameVals,
3812     unsigned FSModRefsAbbrev, unsigned FSModVTableRefsAbbrev) {
3813   auto VI = Index->getValueInfo(V.getGUID());
3814   if (!VI || VI.getSummaryList().empty()) {
3815     // Only declarations should not have a summary (a declaration might however
3816     // have a summary if the def was in module level asm).
3817     assert(V.isDeclaration());
3818     return;
3819   }
3820   auto *Summary = VI.getSummaryList()[0].get();
3821   NameVals.push_back(VE.getValueID(&V));
3822   GlobalVarSummary *VS = cast<GlobalVarSummary>(Summary);
3823   NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
3824   NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
3825 
3826   auto VTableFuncs = VS->vTableFuncs();
3827   if (!VTableFuncs.empty())
3828     NameVals.push_back(VS->refs().size());
3829 
3830   unsigned SizeBeforeRefs = NameVals.size();
3831   for (auto &RI : VS->refs())
3832     NameVals.push_back(VE.getValueID(RI.getValue()));
3833   // Sort the refs for determinism output, the vector returned by FS->refs() has
3834   // been initialized from a DenseSet.
3835   llvm::sort(drop_begin(NameVals, SizeBeforeRefs));
3836 
3837   if (VTableFuncs.empty())
3838     Stream.EmitRecord(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS, NameVals,
3839                       FSModRefsAbbrev);
3840   else {
3841     // VTableFuncs pairs should already be sorted by offset.
3842     for (auto &P : VTableFuncs) {
3843       NameVals.push_back(VE.getValueID(P.FuncVI.getValue()));
3844       NameVals.push_back(P.VTableOffset);
3845     }
3846 
3847     Stream.EmitRecord(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS, NameVals,
3848                       FSModVTableRefsAbbrev);
3849   }
3850   NameVals.clear();
3851 }
3852 
3853 /// Emit the per-module summary section alongside the rest of
3854 /// the module's bitcode.
3855 void ModuleBitcodeWriterBase::writePerModuleGlobalValueSummary() {
3856   // By default we compile with ThinLTO if the module has a summary, but the
3857   // client can request full LTO with a module flag.
3858   bool IsThinLTO = true;
3859   if (auto *MD =
3860           mdconst::extract_or_null<ConstantInt>(M.getModuleFlag("ThinLTO")))
3861     IsThinLTO = MD->getZExtValue();
3862   Stream.EnterSubblock(IsThinLTO ? bitc::GLOBALVAL_SUMMARY_BLOCK_ID
3863                                  : bitc::FULL_LTO_GLOBALVAL_SUMMARY_BLOCK_ID,
3864                        4);
3865 
3866   Stream.EmitRecord(
3867       bitc::FS_VERSION,
3868       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
3869 
3870   // Write the index flags.
3871   uint64_t Flags = 0;
3872   // Bits 1-3 are set only in the combined index, skip them.
3873   if (Index->enableSplitLTOUnit())
3874     Flags |= 0x8;
3875   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Flags});
3876 
3877   if (Index->begin() == Index->end()) {
3878     Stream.ExitBlock();
3879     return;
3880   }
3881 
3882   for (const auto &GVI : valueIds()) {
3883     Stream.EmitRecord(bitc::FS_VALUE_GUID,
3884                       ArrayRef<uint64_t>{GVI.second, GVI.first});
3885   }
3886 
3887   // Abbrev for FS_PERMODULE_PROFILE.
3888   auto Abbv = std::make_shared<BitCodeAbbrev>();
3889   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_PROFILE));
3890   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3891   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3892   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3893   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3894   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3895   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
3896   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
3897   // numrefs x valueid, n x (valueid, hotness)
3898   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3899   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3900   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3901 
3902   // Abbrev for FS_PERMODULE or FS_PERMODULE_RELBF.
3903   Abbv = std::make_shared<BitCodeAbbrev>();
3904   if (WriteRelBFToSummary)
3905     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_RELBF));
3906   else
3907     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE));
3908   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3909   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3910   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3911   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3912   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3913   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
3914   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
3915   // numrefs x valueid, n x (valueid [, rel_block_freq])
3916   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3917   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3918   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3919 
3920   // Abbrev for FS_PERMODULE_GLOBALVAR_INIT_REFS.
3921   Abbv = std::make_shared<BitCodeAbbrev>();
3922   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS));
3923   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
3924   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
3925   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));  // valueids
3926   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3927   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3928 
3929   // Abbrev for FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS.
3930   Abbv = std::make_shared<BitCodeAbbrev>();
3931   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS));
3932   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
3933   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
3934   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numrefs
3935   // numrefs x valueid, n x (valueid , offset)
3936   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3937   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3938   unsigned FSModVTableRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3939 
3940   // Abbrev for FS_ALIAS.
3941   Abbv = std::make_shared<BitCodeAbbrev>();
3942   Abbv->Add(BitCodeAbbrevOp(bitc::FS_ALIAS));
3943   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3944   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3945   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3946   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3947 
3948   // Abbrev for FS_TYPE_ID_METADATA
3949   Abbv = std::make_shared<BitCodeAbbrev>();
3950   Abbv->Add(BitCodeAbbrevOp(bitc::FS_TYPE_ID_METADATA));
3951   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid strtab index
3952   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid length
3953   // n x (valueid , offset)
3954   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3955   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3956   unsigned TypeIdCompatibleVtableAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3957 
3958   SmallVector<uint64_t, 64> NameVals;
3959   // Iterate over the list of functions instead of the Index to
3960   // ensure the ordering is stable.
3961   for (const Function &F : M) {
3962     // Summary emission does not support anonymous functions, they have to
3963     // renamed using the anonymous function renaming pass.
3964     if (!F.hasName())
3965       report_fatal_error("Unexpected anonymous function when writing summary");
3966 
3967     ValueInfo VI = Index->getValueInfo(F.getGUID());
3968     if (!VI || VI.getSummaryList().empty()) {
3969       // Only declarations should not have a summary (a declaration might
3970       // however have a summary if the def was in module level asm).
3971       assert(F.isDeclaration());
3972       continue;
3973     }
3974     auto *Summary = VI.getSummaryList()[0].get();
3975     writePerModuleFunctionSummaryRecord(NameVals, Summary, VE.getValueID(&F),
3976                                         FSCallsAbbrev, FSCallsProfileAbbrev, F);
3977   }
3978 
3979   // Capture references from GlobalVariable initializers, which are outside
3980   // of a function scope.
3981   for (const GlobalVariable &G : M.globals())
3982     writeModuleLevelReferences(G, NameVals, FSModRefsAbbrev,
3983                                FSModVTableRefsAbbrev);
3984 
3985   for (const GlobalAlias &A : M.aliases()) {
3986     auto *Aliasee = A.getBaseObject();
3987     if (!Aliasee->hasName())
3988       // Nameless function don't have an entry in the summary, skip it.
3989       continue;
3990     auto AliasId = VE.getValueID(&A);
3991     auto AliaseeId = VE.getValueID(Aliasee);
3992     NameVals.push_back(AliasId);
3993     auto *Summary = Index->getGlobalValueSummary(A);
3994     AliasSummary *AS = cast<AliasSummary>(Summary);
3995     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
3996     NameVals.push_back(AliaseeId);
3997     Stream.EmitRecord(bitc::FS_ALIAS, NameVals, FSAliasAbbrev);
3998     NameVals.clear();
3999   }
4000 
4001   for (auto &S : Index->typeIdCompatibleVtableMap()) {
4002     writeTypeIdCompatibleVtableSummaryRecord(NameVals, StrtabBuilder, S.first,
4003                                              S.second, VE);
4004     Stream.EmitRecord(bitc::FS_TYPE_ID_METADATA, NameVals,
4005                       TypeIdCompatibleVtableAbbrev);
4006     NameVals.clear();
4007   }
4008 
4009   Stream.EmitRecord(bitc::FS_BLOCK_COUNT,
4010                     ArrayRef<uint64_t>{Index->getBlockCount()});
4011 
4012   Stream.ExitBlock();
4013 }
4014 
4015 /// Emit the combined summary section into the combined index file.
4016 void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
4017   Stream.EnterSubblock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID, 3);
4018   Stream.EmitRecord(
4019       bitc::FS_VERSION,
4020       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
4021 
4022   // Write the index flags.
4023   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Index.getFlags()});
4024 
4025   for (const auto &GVI : valueIds()) {
4026     Stream.EmitRecord(bitc::FS_VALUE_GUID,
4027                       ArrayRef<uint64_t>{GVI.second, GVI.first});
4028   }
4029 
4030   // Abbrev for FS_COMBINED.
4031   auto Abbv = std::make_shared<BitCodeAbbrev>();
4032   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED));
4033   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4034   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4035   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4036   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4037   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4038   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
4039   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4040   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4041   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4042   // numrefs x valueid, n x (valueid)
4043   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4044   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4045   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4046 
4047   // Abbrev for FS_COMBINED_PROFILE.
4048   Abbv = std::make_shared<BitCodeAbbrev>();
4049   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_PROFILE));
4050   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4051   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4052   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4053   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4054   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4055   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
4056   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4057   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4058   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4059   // numrefs x valueid, n x (valueid, hotness)
4060   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4061   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4062   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4063 
4064   // Abbrev for FS_COMBINED_GLOBALVAR_INIT_REFS.
4065   Abbv = std::make_shared<BitCodeAbbrev>();
4066   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS));
4067   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4068   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4069   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4070   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));    // valueids
4071   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4072   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4073 
4074   // Abbrev for FS_COMBINED_ALIAS.
4075   Abbv = std::make_shared<BitCodeAbbrev>();
4076   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_ALIAS));
4077   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4078   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4079   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4080   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4081   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4082 
4083   // The aliases are emitted as a post-pass, and will point to the value
4084   // id of the aliasee. Save them in a vector for post-processing.
4085   SmallVector<AliasSummary *, 64> Aliases;
4086 
4087   // Save the value id for each summary for alias emission.
4088   DenseMap<const GlobalValueSummary *, unsigned> SummaryToValueIdMap;
4089 
4090   SmallVector<uint64_t, 64> NameVals;
4091 
4092   // Set that will be populated during call to writeFunctionTypeMetadataRecords
4093   // with the type ids referenced by this index file.
4094   std::set<GlobalValue::GUID> ReferencedTypeIds;
4095 
4096   // For local linkage, we also emit the original name separately
4097   // immediately after the record.
4098   auto MaybeEmitOriginalName = [&](GlobalValueSummary &S) {
4099     if (!GlobalValue::isLocalLinkage(S.linkage()))
4100       return;
4101     NameVals.push_back(S.getOriginalName());
4102     Stream.EmitRecord(bitc::FS_COMBINED_ORIGINAL_NAME, NameVals);
4103     NameVals.clear();
4104   };
4105 
4106   std::set<GlobalValue::GUID> DefOrUseGUIDs;
4107   forEachSummary([&](GVInfo I, bool IsAliasee) {
4108     GlobalValueSummary *S = I.second;
4109     assert(S);
4110     DefOrUseGUIDs.insert(I.first);
4111     for (const ValueInfo &VI : S->refs())
4112       DefOrUseGUIDs.insert(VI.getGUID());
4113 
4114     auto ValueId = getValueId(I.first);
4115     assert(ValueId);
4116     SummaryToValueIdMap[S] = *ValueId;
4117 
4118     // If this is invoked for an aliasee, we want to record the above
4119     // mapping, but then not emit a summary entry (if the aliasee is
4120     // to be imported, we will invoke this separately with IsAliasee=false).
4121     if (IsAliasee)
4122       return;
4123 
4124     if (auto *AS = dyn_cast<AliasSummary>(S)) {
4125       // Will process aliases as a post-pass because the reader wants all
4126       // global to be loaded first.
4127       Aliases.push_back(AS);
4128       return;
4129     }
4130 
4131     if (auto *VS = dyn_cast<GlobalVarSummary>(S)) {
4132       NameVals.push_back(*ValueId);
4133       NameVals.push_back(Index.getModuleId(VS->modulePath()));
4134       NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
4135       NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
4136       for (auto &RI : VS->refs()) {
4137         auto RefValueId = getValueId(RI.getGUID());
4138         if (!RefValueId)
4139           continue;
4140         NameVals.push_back(*RefValueId);
4141       }
4142 
4143       // Emit the finished record.
4144       Stream.EmitRecord(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS, NameVals,
4145                         FSModRefsAbbrev);
4146       NameVals.clear();
4147       MaybeEmitOriginalName(*S);
4148       return;
4149     }
4150 
4151     auto GetValueId = [&](const ValueInfo &VI) -> Optional<unsigned> {
4152       GlobalValue::GUID GUID = VI.getGUID();
4153       Optional<unsigned> CallValueId = getValueId(GUID);
4154       if (CallValueId)
4155         return CallValueId;
4156       // For SamplePGO, the indirect call targets for local functions will
4157       // have its original name annotated in profile. We try to find the
4158       // corresponding PGOFuncName as the GUID.
4159       GUID = Index.getGUIDFromOriginalID(GUID);
4160       if (!GUID)
4161         return None;
4162       CallValueId = getValueId(GUID);
4163       if (!CallValueId)
4164         return None;
4165       // The mapping from OriginalId to GUID may return a GUID
4166       // that corresponds to a static variable. Filter it out here.
4167       // This can happen when
4168       // 1) There is a call to a library function which does not have
4169       // a CallValidId;
4170       // 2) There is a static variable with the  OriginalGUID identical
4171       // to the GUID of the library function in 1);
4172       // When this happens, the logic for SamplePGO kicks in and
4173       // the static variable in 2) will be found, which needs to be
4174       // filtered out.
4175       auto *GVSum = Index.getGlobalValueSummary(GUID, false);
4176       if (GVSum && GVSum->getSummaryKind() == GlobalValueSummary::GlobalVarKind)
4177         return None;
4178       return CallValueId;
4179     };
4180 
4181     auto *FS = cast<FunctionSummary>(S);
4182     writeFunctionTypeMetadataRecords(Stream, FS, GetValueId);
4183     getReferencedTypeIds(FS, ReferencedTypeIds);
4184 
4185     NameVals.push_back(*ValueId);
4186     NameVals.push_back(Index.getModuleId(FS->modulePath()));
4187     NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
4188     NameVals.push_back(FS->instCount());
4189     NameVals.push_back(getEncodedFFlags(FS->fflags()));
4190     NameVals.push_back(FS->entryCount());
4191 
4192     // Fill in below
4193     NameVals.push_back(0); // numrefs
4194     NameVals.push_back(0); // rorefcnt
4195     NameVals.push_back(0); // worefcnt
4196 
4197     unsigned Count = 0, RORefCnt = 0, WORefCnt = 0;
4198     for (auto &RI : FS->refs()) {
4199       auto RefValueId = getValueId(RI.getGUID());
4200       if (!RefValueId)
4201         continue;
4202       NameVals.push_back(*RefValueId);
4203       if (RI.isReadOnly())
4204         RORefCnt++;
4205       else if (RI.isWriteOnly())
4206         WORefCnt++;
4207       Count++;
4208     }
4209     NameVals[6] = Count;
4210     NameVals[7] = RORefCnt;
4211     NameVals[8] = WORefCnt;
4212 
4213     bool HasProfileData = false;
4214     for (auto &EI : FS->calls()) {
4215       HasProfileData |=
4216           EI.second.getHotness() != CalleeInfo::HotnessType::Unknown;
4217       if (HasProfileData)
4218         break;
4219     }
4220 
4221     for (auto &EI : FS->calls()) {
4222       // If this GUID doesn't have a value id, it doesn't have a function
4223       // summary and we don't need to record any calls to it.
4224       Optional<unsigned> CallValueId = GetValueId(EI.first);
4225       if (!CallValueId)
4226         continue;
4227       NameVals.push_back(*CallValueId);
4228       if (HasProfileData)
4229         NameVals.push_back(static_cast<uint8_t>(EI.second.Hotness));
4230     }
4231 
4232     unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
4233     unsigned Code =
4234         (HasProfileData ? bitc::FS_COMBINED_PROFILE : bitc::FS_COMBINED);
4235 
4236     // Emit the finished record.
4237     Stream.EmitRecord(Code, NameVals, FSAbbrev);
4238     NameVals.clear();
4239     MaybeEmitOriginalName(*S);
4240   });
4241 
4242   for (auto *AS : Aliases) {
4243     auto AliasValueId = SummaryToValueIdMap[AS];
4244     assert(AliasValueId);
4245     NameVals.push_back(AliasValueId);
4246     NameVals.push_back(Index.getModuleId(AS->modulePath()));
4247     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
4248     auto AliaseeValueId = SummaryToValueIdMap[&AS->getAliasee()];
4249     assert(AliaseeValueId);
4250     NameVals.push_back(AliaseeValueId);
4251 
4252     // Emit the finished record.
4253     Stream.EmitRecord(bitc::FS_COMBINED_ALIAS, NameVals, FSAliasAbbrev);
4254     NameVals.clear();
4255     MaybeEmitOriginalName(*AS);
4256 
4257     if (auto *FS = dyn_cast<FunctionSummary>(&AS->getAliasee()))
4258       getReferencedTypeIds(FS, ReferencedTypeIds);
4259   }
4260 
4261   if (!Index.cfiFunctionDefs().empty()) {
4262     for (auto &S : Index.cfiFunctionDefs()) {
4263       if (DefOrUseGUIDs.count(
4264               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4265         NameVals.push_back(StrtabBuilder.add(S));
4266         NameVals.push_back(S.size());
4267       }
4268     }
4269     if (!NameVals.empty()) {
4270       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DEFS, NameVals);
4271       NameVals.clear();
4272     }
4273   }
4274 
4275   if (!Index.cfiFunctionDecls().empty()) {
4276     for (auto &S : Index.cfiFunctionDecls()) {
4277       if (DefOrUseGUIDs.count(
4278               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4279         NameVals.push_back(StrtabBuilder.add(S));
4280         NameVals.push_back(S.size());
4281       }
4282     }
4283     if (!NameVals.empty()) {
4284       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DECLS, NameVals);
4285       NameVals.clear();
4286     }
4287   }
4288 
4289   // Walk the GUIDs that were referenced, and write the
4290   // corresponding type id records.
4291   for (auto &T : ReferencedTypeIds) {
4292     auto TidIter = Index.typeIds().equal_range(T);
4293     for (auto It = TidIter.first; It != TidIter.second; ++It) {
4294       writeTypeIdSummaryRecord(NameVals, StrtabBuilder, It->second.first,
4295                                It->second.second);
4296       Stream.EmitRecord(bitc::FS_TYPE_ID, NameVals);
4297       NameVals.clear();
4298     }
4299   }
4300 
4301   Stream.EmitRecord(bitc::FS_BLOCK_COUNT,
4302                     ArrayRef<uint64_t>{Index.getBlockCount()});
4303 
4304   Stream.ExitBlock();
4305 }
4306 
4307 /// Create the "IDENTIFICATION_BLOCK_ID" containing a single string with the
4308 /// current llvm version, and a record for the epoch number.
4309 static void writeIdentificationBlock(BitstreamWriter &Stream) {
4310   Stream.EnterSubblock(bitc::IDENTIFICATION_BLOCK_ID, 5);
4311 
4312   // Write the "user readable" string identifying the bitcode producer
4313   auto Abbv = std::make_shared<BitCodeAbbrev>();
4314   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_STRING));
4315   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4316   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
4317   auto StringAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4318   writeStringRecord(Stream, bitc::IDENTIFICATION_CODE_STRING,
4319                     "LLVM" LLVM_VERSION_STRING, StringAbbrev);
4320 
4321   // Write the epoch version
4322   Abbv = std::make_shared<BitCodeAbbrev>();
4323   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_EPOCH));
4324   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
4325   auto EpochAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4326   constexpr std::array<unsigned, 1> Vals = {{bitc::BITCODE_CURRENT_EPOCH}};
4327   Stream.EmitRecord(bitc::IDENTIFICATION_CODE_EPOCH, Vals, EpochAbbrev);
4328   Stream.ExitBlock();
4329 }
4330 
4331 void ModuleBitcodeWriter::writeModuleHash(size_t BlockStartPos) {
4332   // Emit the module's hash.
4333   // MODULE_CODE_HASH: [5*i32]
4334   if (GenerateHash) {
4335     uint32_t Vals[5];
4336     Hasher.update(ArrayRef<uint8_t>((const uint8_t *)&(Buffer)[BlockStartPos],
4337                                     Buffer.size() - BlockStartPos));
4338     StringRef Hash = Hasher.result();
4339     for (int Pos = 0; Pos < 20; Pos += 4) {
4340       Vals[Pos / 4] = support::endian::read32be(Hash.data() + Pos);
4341     }
4342 
4343     // Emit the finished record.
4344     Stream.EmitRecord(bitc::MODULE_CODE_HASH, Vals);
4345 
4346     if (ModHash)
4347       // Save the written hash value.
4348       llvm::copy(Vals, std::begin(*ModHash));
4349   }
4350 }
4351 
4352 void ModuleBitcodeWriter::write() {
4353   writeIdentificationBlock(Stream);
4354 
4355   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4356   size_t BlockStartPos = Buffer.size();
4357 
4358   writeModuleVersion();
4359 
4360   // Emit blockinfo, which defines the standard abbreviations etc.
4361   writeBlockInfo();
4362 
4363   // Emit information describing all of the types in the module.
4364   writeTypeTable();
4365 
4366   // Emit information about attribute groups.
4367   writeAttributeGroupTable();
4368 
4369   // Emit information about parameter attributes.
4370   writeAttributeTable();
4371 
4372   writeComdats();
4373 
4374   // Emit top-level description of module, including target triple, inline asm,
4375   // descriptors for global variables, and function prototype info.
4376   writeModuleInfo();
4377 
4378   // Emit constants.
4379   writeModuleConstants();
4380 
4381   // Emit metadata kind names.
4382   writeModuleMetadataKinds();
4383 
4384   // Emit metadata.
4385   writeModuleMetadata();
4386 
4387   // Emit module-level use-lists.
4388   if (VE.shouldPreserveUseListOrder())
4389     writeUseListBlock(nullptr);
4390 
4391   writeOperandBundleTags();
4392   writeSyncScopeNames();
4393 
4394   // Emit function bodies.
4395   DenseMap<const Function *, uint64_t> FunctionToBitcodeIndex;
4396   for (Module::const_iterator F = M.begin(), E = M.end(); F != E; ++F)
4397     if (!F->isDeclaration())
4398       writeFunction(*F, FunctionToBitcodeIndex);
4399 
4400   // Need to write after the above call to WriteFunction which populates
4401   // the summary information in the index.
4402   if (Index)
4403     writePerModuleGlobalValueSummary();
4404 
4405   writeGlobalValueSymbolTable(FunctionToBitcodeIndex);
4406 
4407   writeModuleHash(BlockStartPos);
4408 
4409   Stream.ExitBlock();
4410 }
4411 
4412 static void writeInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
4413                                uint32_t &Position) {
4414   support::endian::write32le(&Buffer[Position], Value);
4415   Position += 4;
4416 }
4417 
4418 /// If generating a bc file on darwin, we have to emit a
4419 /// header and trailer to make it compatible with the system archiver.  To do
4420 /// this we emit the following header, and then emit a trailer that pads the
4421 /// file out to be a multiple of 16 bytes.
4422 ///
4423 /// struct bc_header {
4424 ///   uint32_t Magic;         // 0x0B17C0DE
4425 ///   uint32_t Version;       // Version, currently always 0.
4426 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
4427 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
4428 ///   uint32_t CPUType;       // CPU specifier.
4429 ///   ... potentially more later ...
4430 /// };
4431 static void emitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
4432                                          const Triple &TT) {
4433   unsigned CPUType = ~0U;
4434 
4435   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
4436   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
4437   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
4438   // specific constants here because they are implicitly part of the Darwin ABI.
4439   enum {
4440     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
4441     DARWIN_CPU_TYPE_X86        = 7,
4442     DARWIN_CPU_TYPE_ARM        = 12,
4443     DARWIN_CPU_TYPE_POWERPC    = 18
4444   };
4445 
4446   Triple::ArchType Arch = TT.getArch();
4447   if (Arch == Triple::x86_64)
4448     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
4449   else if (Arch == Triple::x86)
4450     CPUType = DARWIN_CPU_TYPE_X86;
4451   else if (Arch == Triple::ppc)
4452     CPUType = DARWIN_CPU_TYPE_POWERPC;
4453   else if (Arch == Triple::ppc64)
4454     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
4455   else if (Arch == Triple::arm || Arch == Triple::thumb)
4456     CPUType = DARWIN_CPU_TYPE_ARM;
4457 
4458   // Traditional Bitcode starts after header.
4459   assert(Buffer.size() >= BWH_HeaderSize &&
4460          "Expected header size to be reserved");
4461   unsigned BCOffset = BWH_HeaderSize;
4462   unsigned BCSize = Buffer.size() - BWH_HeaderSize;
4463 
4464   // Write the magic and version.
4465   unsigned Position = 0;
4466   writeInt32ToBuffer(0x0B17C0DE, Buffer, Position);
4467   writeInt32ToBuffer(0, Buffer, Position); // Version.
4468   writeInt32ToBuffer(BCOffset, Buffer, Position);
4469   writeInt32ToBuffer(BCSize, Buffer, Position);
4470   writeInt32ToBuffer(CPUType, Buffer, Position);
4471 
4472   // If the file is not a multiple of 16 bytes, insert dummy padding.
4473   while (Buffer.size() & 15)
4474     Buffer.push_back(0);
4475 }
4476 
4477 /// Helper to write the header common to all bitcode files.
4478 static void writeBitcodeHeader(BitstreamWriter &Stream) {
4479   // Emit the file header.
4480   Stream.Emit((unsigned)'B', 8);
4481   Stream.Emit((unsigned)'C', 8);
4482   Stream.Emit(0x0, 4);
4483   Stream.Emit(0xC, 4);
4484   Stream.Emit(0xE, 4);
4485   Stream.Emit(0xD, 4);
4486 }
4487 
4488 BitcodeWriter::BitcodeWriter(SmallVectorImpl<char> &Buffer, raw_fd_stream *FS)
4489     : Buffer(Buffer), Stream(new BitstreamWriter(Buffer, FS, FlushThreshold)) {
4490   writeBitcodeHeader(*Stream);
4491 }
4492 
4493 BitcodeWriter::~BitcodeWriter() { assert(WroteStrtab); }
4494 
4495 void BitcodeWriter::writeBlob(unsigned Block, unsigned Record, StringRef Blob) {
4496   Stream->EnterSubblock(Block, 3);
4497 
4498   auto Abbv = std::make_shared<BitCodeAbbrev>();
4499   Abbv->Add(BitCodeAbbrevOp(Record));
4500   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
4501   auto AbbrevNo = Stream->EmitAbbrev(std::move(Abbv));
4502 
4503   Stream->EmitRecordWithBlob(AbbrevNo, ArrayRef<uint64_t>{Record}, Blob);
4504 
4505   Stream->ExitBlock();
4506 }
4507 
4508 void BitcodeWriter::writeSymtab() {
4509   assert(!WroteStrtab && !WroteSymtab);
4510 
4511   // If any module has module-level inline asm, we will require a registered asm
4512   // parser for the target so that we can create an accurate symbol table for
4513   // the module.
4514   for (Module *M : Mods) {
4515     if (M->getModuleInlineAsm().empty())
4516       continue;
4517 
4518     std::string Err;
4519     const Triple TT(M->getTargetTriple());
4520     const Target *T = TargetRegistry::lookupTarget(TT.str(), Err);
4521     if (!T || !T->hasMCAsmParser())
4522       return;
4523   }
4524 
4525   WroteSymtab = true;
4526   SmallVector<char, 0> Symtab;
4527   // The irsymtab::build function may be unable to create a symbol table if the
4528   // module is malformed (e.g. it contains an invalid alias). Writing a symbol
4529   // table is not required for correctness, but we still want to be able to
4530   // write malformed modules to bitcode files, so swallow the error.
4531   if (Error E = irsymtab::build(Mods, Symtab, StrtabBuilder, Alloc)) {
4532     consumeError(std::move(E));
4533     return;
4534   }
4535 
4536   writeBlob(bitc::SYMTAB_BLOCK_ID, bitc::SYMTAB_BLOB,
4537             {Symtab.data(), Symtab.size()});
4538 }
4539 
4540 void BitcodeWriter::writeStrtab() {
4541   assert(!WroteStrtab);
4542 
4543   std::vector<char> Strtab;
4544   StrtabBuilder.finalizeInOrder();
4545   Strtab.resize(StrtabBuilder.getSize());
4546   StrtabBuilder.write((uint8_t *)Strtab.data());
4547 
4548   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB,
4549             {Strtab.data(), Strtab.size()});
4550 
4551   WroteStrtab = true;
4552 }
4553 
4554 void BitcodeWriter::copyStrtab(StringRef Strtab) {
4555   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB, Strtab);
4556   WroteStrtab = true;
4557 }
4558 
4559 void BitcodeWriter::writeModule(const Module &M,
4560                                 bool ShouldPreserveUseListOrder,
4561                                 const ModuleSummaryIndex *Index,
4562                                 bool GenerateHash, ModuleHash *ModHash) {
4563   assert(!WroteStrtab);
4564 
4565   // The Mods vector is used by irsymtab::build, which requires non-const
4566   // Modules in case it needs to materialize metadata. But the bitcode writer
4567   // requires that the module is materialized, so we can cast to non-const here,
4568   // after checking that it is in fact materialized.
4569   assert(M.isMaterialized());
4570   Mods.push_back(const_cast<Module *>(&M));
4571 
4572   ModuleBitcodeWriter ModuleWriter(M, Buffer, StrtabBuilder, *Stream,
4573                                    ShouldPreserveUseListOrder, Index,
4574                                    GenerateHash, ModHash);
4575   ModuleWriter.write();
4576 }
4577 
4578 void BitcodeWriter::writeIndex(
4579     const ModuleSummaryIndex *Index,
4580     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4581   IndexBitcodeWriter IndexWriter(*Stream, StrtabBuilder, *Index,
4582                                  ModuleToSummariesForIndex);
4583   IndexWriter.write();
4584 }
4585 
4586 /// Write the specified module to the specified output stream.
4587 void llvm::WriteBitcodeToFile(const Module &M, raw_ostream &Out,
4588                               bool ShouldPreserveUseListOrder,
4589                               const ModuleSummaryIndex *Index,
4590                               bool GenerateHash, ModuleHash *ModHash) {
4591   SmallVector<char, 0> Buffer;
4592   Buffer.reserve(256*1024);
4593 
4594   // If this is darwin or another generic macho target, reserve space for the
4595   // header.
4596   Triple TT(M.getTargetTriple());
4597   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4598     Buffer.insert(Buffer.begin(), BWH_HeaderSize, 0);
4599 
4600   BitcodeWriter Writer(Buffer, dyn_cast<raw_fd_stream>(&Out));
4601   Writer.writeModule(M, ShouldPreserveUseListOrder, Index, GenerateHash,
4602                      ModHash);
4603   Writer.writeSymtab();
4604   Writer.writeStrtab();
4605 
4606   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4607     emitDarwinBCHeaderAndTrailer(Buffer, TT);
4608 
4609   // Write the generated bitstream to "Out".
4610   if (!Buffer.empty())
4611     Out.write((char *)&Buffer.front(), Buffer.size());
4612 }
4613 
4614 void IndexBitcodeWriter::write() {
4615   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4616 
4617   writeModuleVersion();
4618 
4619   // Write the module paths in the combined index.
4620   writeModStrings();
4621 
4622   // Write the summary combined index records.
4623   writeCombinedGlobalValueSummary();
4624 
4625   Stream.ExitBlock();
4626 }
4627 
4628 // Write the specified module summary index to the given raw output stream,
4629 // where it will be written in a new bitcode block. This is used when
4630 // writing the combined index file for ThinLTO. When writing a subset of the
4631 // index for a distributed backend, provide a \p ModuleToSummariesForIndex map.
4632 void llvm::WriteIndexToFile(
4633     const ModuleSummaryIndex &Index, raw_ostream &Out,
4634     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4635   SmallVector<char, 0> Buffer;
4636   Buffer.reserve(256 * 1024);
4637 
4638   BitcodeWriter Writer(Buffer);
4639   Writer.writeIndex(&Index, ModuleToSummariesForIndex);
4640   Writer.writeStrtab();
4641 
4642   Out.write((char *)&Buffer.front(), Buffer.size());
4643 }
4644 
4645 namespace {
4646 
4647 /// Class to manage the bitcode writing for a thin link bitcode file.
4648 class ThinLinkBitcodeWriter : public ModuleBitcodeWriterBase {
4649   /// ModHash is for use in ThinLTO incremental build, generated while writing
4650   /// the module bitcode file.
4651   const ModuleHash *ModHash;
4652 
4653 public:
4654   ThinLinkBitcodeWriter(const Module &M, StringTableBuilder &StrtabBuilder,
4655                         BitstreamWriter &Stream,
4656                         const ModuleSummaryIndex &Index,
4657                         const ModuleHash &ModHash)
4658       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
4659                                 /*ShouldPreserveUseListOrder=*/false, &Index),
4660         ModHash(&ModHash) {}
4661 
4662   void write();
4663 
4664 private:
4665   void writeSimplifiedModuleInfo();
4666 };
4667 
4668 } // end anonymous namespace
4669 
4670 // This function writes a simpilified module info for thin link bitcode file.
4671 // It only contains the source file name along with the name(the offset and
4672 // size in strtab) and linkage for global values. For the global value info
4673 // entry, in order to keep linkage at offset 5, there are three zeros used
4674 // as padding.
4675 void ThinLinkBitcodeWriter::writeSimplifiedModuleInfo() {
4676   SmallVector<unsigned, 64> Vals;
4677   // Emit the module's source file name.
4678   {
4679     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
4680     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
4681     if (Bits == SE_Char6)
4682       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
4683     else if (Bits == SE_Fixed7)
4684       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
4685 
4686     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
4687     auto Abbv = std::make_shared<BitCodeAbbrev>();
4688     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
4689     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4690     Abbv->Add(AbbrevOpToUse);
4691     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4692 
4693     for (const auto P : M.getSourceFileName())
4694       Vals.push_back((unsigned char)P);
4695 
4696     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
4697     Vals.clear();
4698   }
4699 
4700   // Emit the global variable information.
4701   for (const GlobalVariable &GV : M.globals()) {
4702     // GLOBALVAR: [strtab offset, strtab size, 0, 0, 0, linkage]
4703     Vals.push_back(StrtabBuilder.add(GV.getName()));
4704     Vals.push_back(GV.getName().size());
4705     Vals.push_back(0);
4706     Vals.push_back(0);
4707     Vals.push_back(0);
4708     Vals.push_back(getEncodedLinkage(GV));
4709 
4710     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals);
4711     Vals.clear();
4712   }
4713 
4714   // Emit the function proto information.
4715   for (const Function &F : M) {
4716     // FUNCTION:  [strtab offset, strtab size, 0, 0, 0, linkage]
4717     Vals.push_back(StrtabBuilder.add(F.getName()));
4718     Vals.push_back(F.getName().size());
4719     Vals.push_back(0);
4720     Vals.push_back(0);
4721     Vals.push_back(0);
4722     Vals.push_back(getEncodedLinkage(F));
4723 
4724     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals);
4725     Vals.clear();
4726   }
4727 
4728   // Emit the alias information.
4729   for (const GlobalAlias &A : M.aliases()) {
4730     // ALIAS: [strtab offset, strtab size, 0, 0, 0, linkage]
4731     Vals.push_back(StrtabBuilder.add(A.getName()));
4732     Vals.push_back(A.getName().size());
4733     Vals.push_back(0);
4734     Vals.push_back(0);
4735     Vals.push_back(0);
4736     Vals.push_back(getEncodedLinkage(A));
4737 
4738     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals);
4739     Vals.clear();
4740   }
4741 
4742   // Emit the ifunc information.
4743   for (const GlobalIFunc &I : M.ifuncs()) {
4744     // IFUNC: [strtab offset, strtab size, 0, 0, 0, linkage]
4745     Vals.push_back(StrtabBuilder.add(I.getName()));
4746     Vals.push_back(I.getName().size());
4747     Vals.push_back(0);
4748     Vals.push_back(0);
4749     Vals.push_back(0);
4750     Vals.push_back(getEncodedLinkage(I));
4751 
4752     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
4753     Vals.clear();
4754   }
4755 }
4756 
4757 void ThinLinkBitcodeWriter::write() {
4758   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4759 
4760   writeModuleVersion();
4761 
4762   writeSimplifiedModuleInfo();
4763 
4764   writePerModuleGlobalValueSummary();
4765 
4766   // Write module hash.
4767   Stream.EmitRecord(bitc::MODULE_CODE_HASH, ArrayRef<uint32_t>(*ModHash));
4768 
4769   Stream.ExitBlock();
4770 }
4771 
4772 void BitcodeWriter::writeThinLinkBitcode(const Module &M,
4773                                          const ModuleSummaryIndex &Index,
4774                                          const ModuleHash &ModHash) {
4775   assert(!WroteStrtab);
4776 
4777   // The Mods vector is used by irsymtab::build, which requires non-const
4778   // Modules in case it needs to materialize metadata. But the bitcode writer
4779   // requires that the module is materialized, so we can cast to non-const here,
4780   // after checking that it is in fact materialized.
4781   assert(M.isMaterialized());
4782   Mods.push_back(const_cast<Module *>(&M));
4783 
4784   ThinLinkBitcodeWriter ThinLinkWriter(M, StrtabBuilder, *Stream, Index,
4785                                        ModHash);
4786   ThinLinkWriter.write();
4787 }
4788 
4789 // Write the specified thin link bitcode file to the given raw output stream,
4790 // where it will be written in a new bitcode block. This is used when
4791 // writing the per-module index file for ThinLTO.
4792 void llvm::WriteThinLinkBitcodeToFile(const Module &M, raw_ostream &Out,
4793                                       const ModuleSummaryIndex &Index,
4794                                       const ModuleHash &ModHash) {
4795   SmallVector<char, 0> Buffer;
4796   Buffer.reserve(256 * 1024);
4797 
4798   BitcodeWriter Writer(Buffer);
4799   Writer.writeThinLinkBitcode(M, Index, ModHash);
4800   Writer.writeSymtab();
4801   Writer.writeStrtab();
4802 
4803   Out.write((char *)&Buffer.front(), Buffer.size());
4804 }
4805 
4806 static const char *getSectionNameForBitcode(const Triple &T) {
4807   switch (T.getObjectFormat()) {
4808   case Triple::MachO:
4809     return "__LLVM,__bitcode";
4810   case Triple::COFF:
4811   case Triple::ELF:
4812   case Triple::Wasm:
4813   case Triple::UnknownObjectFormat:
4814     return ".llvmbc";
4815   case Triple::GOFF:
4816     llvm_unreachable("GOFF is not yet implemented");
4817     break;
4818   case Triple::XCOFF:
4819     llvm_unreachable("XCOFF is not yet implemented");
4820     break;
4821   }
4822   llvm_unreachable("Unimplemented ObjectFormatType");
4823 }
4824 
4825 static const char *getSectionNameForCommandline(const Triple &T) {
4826   switch (T.getObjectFormat()) {
4827   case Triple::MachO:
4828     return "__LLVM,__cmdline";
4829   case Triple::COFF:
4830   case Triple::ELF:
4831   case Triple::Wasm:
4832   case Triple::UnknownObjectFormat:
4833     return ".llvmcmd";
4834   case Triple::GOFF:
4835     llvm_unreachable("GOFF is not yet implemented");
4836     break;
4837   case Triple::XCOFF:
4838     llvm_unreachable("XCOFF is not yet implemented");
4839     break;
4840   }
4841   llvm_unreachable("Unimplemented ObjectFormatType");
4842 }
4843 
4844 void llvm::EmbedBitcodeInModule(llvm::Module &M, llvm::MemoryBufferRef Buf,
4845                                 bool EmbedBitcode, bool EmbedCmdline,
4846                                 const std::vector<uint8_t> &CmdArgs) {
4847   // Save llvm.compiler.used and remove it.
4848   SmallVector<Constant *, 2> UsedArray;
4849   SmallPtrSet<GlobalValue *, 4> UsedGlobals;
4850   Type *UsedElementType = Type::getInt8Ty(M.getContext())->getPointerTo(0);
4851   GlobalVariable *Used = collectUsedGlobalVariables(M, UsedGlobals, true);
4852   for (auto *GV : UsedGlobals) {
4853     if (GV->getName() != "llvm.embedded.module" &&
4854         GV->getName() != "llvm.cmdline")
4855       UsedArray.push_back(
4856           ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
4857   }
4858   if (Used)
4859     Used->eraseFromParent();
4860 
4861   // Embed the bitcode for the llvm module.
4862   std::string Data;
4863   ArrayRef<uint8_t> ModuleData;
4864   Triple T(M.getTargetTriple());
4865 
4866   if (EmbedBitcode) {
4867     if (Buf.getBufferSize() == 0 ||
4868         !isBitcode((const unsigned char *)Buf.getBufferStart(),
4869                    (const unsigned char *)Buf.getBufferEnd())) {
4870       // If the input is LLVM Assembly, bitcode is produced by serializing
4871       // the module. Use-lists order need to be preserved in this case.
4872       llvm::raw_string_ostream OS(Data);
4873       llvm::WriteBitcodeToFile(M, OS, /* ShouldPreserveUseListOrder */ true);
4874       ModuleData =
4875           ArrayRef<uint8_t>((const uint8_t *)OS.str().data(), OS.str().size());
4876     } else
4877       // If the input is LLVM bitcode, write the input byte stream directly.
4878       ModuleData = ArrayRef<uint8_t>((const uint8_t *)Buf.getBufferStart(),
4879                                      Buf.getBufferSize());
4880   }
4881   llvm::Constant *ModuleConstant =
4882       llvm::ConstantDataArray::get(M.getContext(), ModuleData);
4883   llvm::GlobalVariable *GV = new llvm::GlobalVariable(
4884       M, ModuleConstant->getType(), true, llvm::GlobalValue::PrivateLinkage,
4885       ModuleConstant);
4886   GV->setSection(getSectionNameForBitcode(T));
4887   // Set alignment to 1 to prevent padding between two contributions from input
4888   // sections after linking.
4889   GV->setAlignment(Align(1));
4890   UsedArray.push_back(
4891       ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
4892   if (llvm::GlobalVariable *Old =
4893           M.getGlobalVariable("llvm.embedded.module", true)) {
4894     assert(Old->hasOneUse() &&
4895            "llvm.embedded.module can only be used once in llvm.compiler.used");
4896     GV->takeName(Old);
4897     Old->eraseFromParent();
4898   } else {
4899     GV->setName("llvm.embedded.module");
4900   }
4901 
4902   // Skip if only bitcode needs to be embedded.
4903   if (EmbedCmdline) {
4904     // Embed command-line options.
4905     ArrayRef<uint8_t> CmdData(const_cast<uint8_t *>(CmdArgs.data()),
4906                               CmdArgs.size());
4907     llvm::Constant *CmdConstant =
4908         llvm::ConstantDataArray::get(M.getContext(), CmdData);
4909     GV = new llvm::GlobalVariable(M, CmdConstant->getType(), true,
4910                                   llvm::GlobalValue::PrivateLinkage,
4911                                   CmdConstant);
4912     GV->setSection(getSectionNameForCommandline(T));
4913     GV->setAlignment(Align(1));
4914     UsedArray.push_back(
4915         ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
4916     if (llvm::GlobalVariable *Old = M.getGlobalVariable("llvm.cmdline", true)) {
4917       assert(Old->hasOneUse() &&
4918              "llvm.cmdline can only be used once in llvm.compiler.used");
4919       GV->takeName(Old);
4920       Old->eraseFromParent();
4921     } else {
4922       GV->setName("llvm.cmdline");
4923     }
4924   }
4925 
4926   if (UsedArray.empty())
4927     return;
4928 
4929   // Recreate llvm.compiler.used.
4930   ArrayType *ATy = ArrayType::get(UsedElementType, UsedArray.size());
4931   auto *NewUsed = new GlobalVariable(
4932       M, ATy, false, llvm::GlobalValue::AppendingLinkage,
4933       llvm::ConstantArray::get(ATy, UsedArray), "llvm.compiler.used");
4934   NewUsed->setSection("llvm.metadata");
4935 }
4936