xref: /llvm-project/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp (revision 12e78ff88105f2dc6cb1449d6fcd5d8f69e0512f)
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/SetVector.h"
23 #include "llvm/ADT/SmallPtrSet.h"
24 #include "llvm/ADT/SmallString.h"
25 #include "llvm/ADT/SmallVector.h"
26 #include "llvm/ADT/StringMap.h"
27 #include "llvm/ADT/StringRef.h"
28 #include "llvm/ADT/Triple.h"
29 #include "llvm/Bitcode/BitcodeCommon.h"
30 #include "llvm/Bitcode/BitcodeReader.h"
31 #include "llvm/Bitcode/LLVMBitCodes.h"
32 #include "llvm/Bitstream/BitCodes.h"
33 #include "llvm/Bitstream/BitstreamWriter.h"
34 #include "llvm/Config/llvm-config.h"
35 #include "llvm/IR/Attributes.h"
36 #include "llvm/IR/BasicBlock.h"
37 #include "llvm/IR/Comdat.h"
38 #include "llvm/IR/Constant.h"
39 #include "llvm/IR/Constants.h"
40 #include "llvm/IR/DebugInfoMetadata.h"
41 #include "llvm/IR/DebugLoc.h"
42 #include "llvm/IR/DerivedTypes.h"
43 #include "llvm/IR/Function.h"
44 #include "llvm/IR/GlobalAlias.h"
45 #include "llvm/IR/GlobalIFunc.h"
46 #include "llvm/IR/GlobalObject.h"
47 #include "llvm/IR/GlobalValue.h"
48 #include "llvm/IR/GlobalVariable.h"
49 #include "llvm/IR/InlineAsm.h"
50 #include "llvm/IR/InstrTypes.h"
51 #include "llvm/IR/Instruction.h"
52 #include "llvm/IR/Instructions.h"
53 #include "llvm/IR/LLVMContext.h"
54 #include "llvm/IR/Metadata.h"
55 #include "llvm/IR/Module.h"
56 #include "llvm/IR/ModuleSummaryIndex.h"
57 #include "llvm/IR/Operator.h"
58 #include "llvm/IR/Type.h"
59 #include "llvm/IR/UseListOrder.h"
60 #include "llvm/IR/Value.h"
61 #include "llvm/IR/ValueSymbolTable.h"
62 #include "llvm/MC/StringTableBuilder.h"
63 #include "llvm/MC/TargetRegistry.h"
64 #include "llvm/Object/IRSymtab.h"
65 #include "llvm/Support/AtomicOrdering.h"
66 #include "llvm/Support/Casting.h"
67 #include "llvm/Support/CommandLine.h"
68 #include "llvm/Support/Endian.h"
69 #include "llvm/Support/Error.h"
70 #include "llvm/Support/ErrorHandling.h"
71 #include "llvm/Support/MathExtras.h"
72 #include "llvm/Support/SHA1.h"
73 #include "llvm/Support/raw_ostream.h"
74 #include <algorithm>
75 #include <cassert>
76 #include <cstddef>
77 #include <cstdint>
78 #include <iterator>
79 #include <map>
80 #include <memory>
81 #include <string>
82 #include <utility>
83 #include <vector>
84 
85 using namespace llvm;
86 
87 static cl::opt<unsigned>
88     IndexThreshold("bitcode-mdindex-threshold", cl::Hidden, cl::init(25),
89                    cl::desc("Number of metadatas above which we emit an index "
90                             "to enable lazy-loading"));
91 static cl::opt<uint32_t> FlushThreshold(
92     "bitcode-flush-threshold", cl::Hidden, cl::init(512),
93     cl::desc("The threshold (unit M) for flushing LLVM bitcode."));
94 
95 static cl::opt<bool> WriteRelBFToSummary(
96     "write-relbf-to-summary", cl::Hidden, cl::init(false),
97     cl::desc("Write relative block frequency to function summary "));
98 
99 extern FunctionSummary::ForceSummaryHotnessType ForceSummaryEdgesCold;
100 
101 namespace {
102 
103 /// These are manifest constants used by the bitcode writer. They do not need to
104 /// be kept in sync with the reader, but need to be consistent within this file.
105 enum {
106   // VALUE_SYMTAB_BLOCK abbrev id's.
107   VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
108   VST_ENTRY_7_ABBREV,
109   VST_ENTRY_6_ABBREV,
110   VST_BBENTRY_6_ABBREV,
111 
112   // CONSTANTS_BLOCK abbrev id's.
113   CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
114   CONSTANTS_INTEGER_ABBREV,
115   CONSTANTS_CE_CAST_Abbrev,
116   CONSTANTS_NULL_Abbrev,
117 
118   // FUNCTION_BLOCK abbrev id's.
119   FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
120   FUNCTION_INST_UNOP_ABBREV,
121   FUNCTION_INST_UNOP_FLAGS_ABBREV,
122   FUNCTION_INST_BINOP_ABBREV,
123   FUNCTION_INST_BINOP_FLAGS_ABBREV,
124   FUNCTION_INST_CAST_ABBREV,
125   FUNCTION_INST_RET_VOID_ABBREV,
126   FUNCTION_INST_RET_VAL_ABBREV,
127   FUNCTION_INST_UNREACHABLE_ABBREV,
128   FUNCTION_INST_GEP_ABBREV,
129 };
130 
131 /// Abstract class to manage the bitcode writing, subclassed for each bitcode
132 /// file type.
133 class BitcodeWriterBase {
134 protected:
135   /// The stream created and owned by the client.
136   BitstreamWriter &Stream;
137 
138   StringTableBuilder &StrtabBuilder;
139 
140 public:
141   /// Constructs a BitcodeWriterBase object that writes to the provided
142   /// \p Stream.
143   BitcodeWriterBase(BitstreamWriter &Stream, StringTableBuilder &StrtabBuilder)
144       : Stream(Stream), StrtabBuilder(StrtabBuilder) {}
145 
146 protected:
147   void writeModuleVersion();
148 };
149 
150 void BitcodeWriterBase::writeModuleVersion() {
151   // VERSION: [version#]
152   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, ArrayRef<uint64_t>{2});
153 }
154 
155 /// Base class to manage the module bitcode writing, currently subclassed for
156 /// ModuleBitcodeWriter and ThinLinkBitcodeWriter.
157 class ModuleBitcodeWriterBase : public BitcodeWriterBase {
158 protected:
159   /// The Module to write to bitcode.
160   const Module &M;
161 
162   /// Enumerates ids for all values in the module.
163   ValueEnumerator VE;
164 
165   /// Optional per-module index to write for ThinLTO.
166   const ModuleSummaryIndex *Index;
167 
168   /// Map that holds the correspondence between GUIDs in the summary index,
169   /// that came from indirect call profiles, and a value id generated by this
170   /// class to use in the VST and summary block records.
171   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
172 
173   /// Tracks the last value id recorded in the GUIDToValueMap.
174   unsigned GlobalValueId;
175 
176   /// Saves the offset of the VSTOffset record that must eventually be
177   /// backpatched with the offset of the actual VST.
178   uint64_t VSTOffsetPlaceholder = 0;
179 
180 public:
181   /// Constructs a ModuleBitcodeWriterBase object for the given Module,
182   /// writing to the provided \p Buffer.
183   ModuleBitcodeWriterBase(const Module &M, StringTableBuilder &StrtabBuilder,
184                           BitstreamWriter &Stream,
185                           bool ShouldPreserveUseListOrder,
186                           const ModuleSummaryIndex *Index)
187       : BitcodeWriterBase(Stream, StrtabBuilder), M(M),
188         VE(M, ShouldPreserveUseListOrder), Index(Index) {
189     // Assign ValueIds to any callee values in the index that came from
190     // indirect call profiles and were recorded as a GUID not a Value*
191     // (which would have been assigned an ID by the ValueEnumerator).
192     // The starting ValueId is just after the number of values in the
193     // ValueEnumerator, so that they can be emitted in the VST.
194     GlobalValueId = VE.getValues().size();
195     if (!Index)
196       return;
197     for (const auto &GUIDSummaryLists : *Index)
198       // Examine all summaries for this GUID.
199       for (auto &Summary : GUIDSummaryLists.second.SummaryList)
200         if (auto FS = dyn_cast<FunctionSummary>(Summary.get()))
201           // For each call in the function summary, see if the call
202           // is to a GUID (which means it is for an indirect call,
203           // otherwise we would have a Value for it). If so, synthesize
204           // a value id.
205           for (auto &CallEdge : FS->calls())
206             if (!CallEdge.first.haveGVs() || !CallEdge.first.getValue())
207               assignValueId(CallEdge.first.getGUID());
208   }
209 
210 protected:
211   void writePerModuleGlobalValueSummary();
212 
213 private:
214   void writePerModuleFunctionSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
215                                            GlobalValueSummary *Summary,
216                                            unsigned ValueID,
217                                            unsigned FSCallsAbbrev,
218                                            unsigned FSCallsProfileAbbrev,
219                                            const Function &F);
220   void writeModuleLevelReferences(const GlobalVariable &V,
221                                   SmallVector<uint64_t, 64> &NameVals,
222                                   unsigned FSModRefsAbbrev,
223                                   unsigned FSModVTableRefsAbbrev);
224 
225   void assignValueId(GlobalValue::GUID ValGUID) {
226     GUIDToValueIdMap[ValGUID] = ++GlobalValueId;
227   }
228 
229   unsigned getValueId(GlobalValue::GUID ValGUID) {
230     const auto &VMI = GUIDToValueIdMap.find(ValGUID);
231     // Expect that any GUID value had a value Id assigned by an
232     // earlier call to assignValueId.
233     assert(VMI != GUIDToValueIdMap.end() &&
234            "GUID does not have assigned value Id");
235     return VMI->second;
236   }
237 
238   // Helper to get the valueId for the type of value recorded in VI.
239   unsigned getValueId(ValueInfo VI) {
240     if (!VI.haveGVs() || !VI.getValue())
241       return getValueId(VI.getGUID());
242     return VE.getValueID(VI.getValue());
243   }
244 
245   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
246 };
247 
248 /// Class to manage the bitcode writing for a module.
249 class ModuleBitcodeWriter : public ModuleBitcodeWriterBase {
250   /// Pointer to the buffer allocated by caller for bitcode writing.
251   const SmallVectorImpl<char> &Buffer;
252 
253   /// True if a module hash record should be written.
254   bool GenerateHash;
255 
256   /// If non-null, when GenerateHash is true, the resulting hash is written
257   /// into ModHash.
258   ModuleHash *ModHash;
259 
260   SHA1 Hasher;
261 
262   /// The start bit of the identification block.
263   uint64_t BitcodeStartBit;
264 
265 public:
266   /// Constructs a ModuleBitcodeWriter object for the given Module,
267   /// writing to the provided \p Buffer.
268   ModuleBitcodeWriter(const Module &M, SmallVectorImpl<char> &Buffer,
269                       StringTableBuilder &StrtabBuilder,
270                       BitstreamWriter &Stream, bool ShouldPreserveUseListOrder,
271                       const ModuleSummaryIndex *Index, bool GenerateHash,
272                       ModuleHash *ModHash = nullptr)
273       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
274                                 ShouldPreserveUseListOrder, Index),
275         Buffer(Buffer), GenerateHash(GenerateHash), ModHash(ModHash),
276         BitcodeStartBit(Stream.GetCurrentBitNo()) {}
277 
278   /// Emit the current module to the bitstream.
279   void write();
280 
281 private:
282   uint64_t bitcodeStartBit() { return BitcodeStartBit; }
283 
284   size_t addToStrtab(StringRef Str);
285 
286   void writeAttributeGroupTable();
287   void writeAttributeTable();
288   void writeTypeTable();
289   void writeComdats();
290   void writeValueSymbolTableForwardDecl();
291   void writeModuleInfo();
292   void writeValueAsMetadata(const ValueAsMetadata *MD,
293                             SmallVectorImpl<uint64_t> &Record);
294   void writeMDTuple(const MDTuple *N, SmallVectorImpl<uint64_t> &Record,
295                     unsigned Abbrev);
296   unsigned createDILocationAbbrev();
297   void writeDILocation(const DILocation *N, SmallVectorImpl<uint64_t> &Record,
298                        unsigned &Abbrev);
299   unsigned createGenericDINodeAbbrev();
300   void writeGenericDINode(const GenericDINode *N,
301                           SmallVectorImpl<uint64_t> &Record, unsigned &Abbrev);
302   void writeDISubrange(const DISubrange *N, SmallVectorImpl<uint64_t> &Record,
303                        unsigned Abbrev);
304   void writeDIGenericSubrange(const DIGenericSubrange *N,
305                               SmallVectorImpl<uint64_t> &Record,
306                               unsigned Abbrev);
307   void writeDIEnumerator(const DIEnumerator *N,
308                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
309   void writeDIBasicType(const DIBasicType *N, SmallVectorImpl<uint64_t> &Record,
310                         unsigned Abbrev);
311   void writeDIStringType(const DIStringType *N,
312                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
313   void writeDIDerivedType(const DIDerivedType *N,
314                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
315   void writeDICompositeType(const DICompositeType *N,
316                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
317   void writeDISubroutineType(const DISubroutineType *N,
318                              SmallVectorImpl<uint64_t> &Record,
319                              unsigned Abbrev);
320   void writeDIFile(const DIFile *N, SmallVectorImpl<uint64_t> &Record,
321                    unsigned Abbrev);
322   void writeDICompileUnit(const DICompileUnit *N,
323                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
324   void writeDISubprogram(const DISubprogram *N,
325                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
326   void writeDILexicalBlock(const DILexicalBlock *N,
327                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
328   void writeDILexicalBlockFile(const DILexicalBlockFile *N,
329                                SmallVectorImpl<uint64_t> &Record,
330                                unsigned Abbrev);
331   void writeDICommonBlock(const DICommonBlock *N,
332                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
333   void writeDINamespace(const DINamespace *N, SmallVectorImpl<uint64_t> &Record,
334                         unsigned Abbrev);
335   void writeDIMacro(const DIMacro *N, SmallVectorImpl<uint64_t> &Record,
336                     unsigned Abbrev);
337   void writeDIMacroFile(const DIMacroFile *N, SmallVectorImpl<uint64_t> &Record,
338                         unsigned Abbrev);
339   void writeDIArgList(const DIArgList *N, SmallVectorImpl<uint64_t> &Record,
340                       unsigned Abbrev);
341   void writeDIModule(const DIModule *N, SmallVectorImpl<uint64_t> &Record,
342                      unsigned Abbrev);
343   void writeDITemplateTypeParameter(const DITemplateTypeParameter *N,
344                                     SmallVectorImpl<uint64_t> &Record,
345                                     unsigned Abbrev);
346   void writeDITemplateValueParameter(const DITemplateValueParameter *N,
347                                      SmallVectorImpl<uint64_t> &Record,
348                                      unsigned Abbrev);
349   void writeDIGlobalVariable(const DIGlobalVariable *N,
350                              SmallVectorImpl<uint64_t> &Record,
351                              unsigned Abbrev);
352   void writeDILocalVariable(const DILocalVariable *N,
353                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
354   void writeDILabel(const DILabel *N,
355                     SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
356   void writeDIExpression(const DIExpression *N,
357                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
358   void writeDIGlobalVariableExpression(const DIGlobalVariableExpression *N,
359                                        SmallVectorImpl<uint64_t> &Record,
360                                        unsigned Abbrev);
361   void writeDIObjCProperty(const DIObjCProperty *N,
362                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
363   void writeDIImportedEntity(const DIImportedEntity *N,
364                              SmallVectorImpl<uint64_t> &Record,
365                              unsigned Abbrev);
366   unsigned createNamedMetadataAbbrev();
367   void writeNamedMetadata(SmallVectorImpl<uint64_t> &Record);
368   unsigned createMetadataStringsAbbrev();
369   void writeMetadataStrings(ArrayRef<const Metadata *> Strings,
370                             SmallVectorImpl<uint64_t> &Record);
371   void writeMetadataRecords(ArrayRef<const Metadata *> MDs,
372                             SmallVectorImpl<uint64_t> &Record,
373                             std::vector<unsigned> *MDAbbrevs = nullptr,
374                             std::vector<uint64_t> *IndexPos = nullptr);
375   void writeModuleMetadata();
376   void writeFunctionMetadata(const Function &F);
377   void writeFunctionMetadataAttachment(const Function &F);
378   void pushGlobalMetadataAttachment(SmallVectorImpl<uint64_t> &Record,
379                                     const GlobalObject &GO);
380   void writeModuleMetadataKinds();
381   void writeOperandBundleTags();
382   void writeSyncScopeNames();
383   void writeConstants(unsigned FirstVal, unsigned LastVal, bool isGlobal);
384   void writeModuleConstants();
385   bool pushValueAndType(const Value *V, unsigned InstID,
386                         SmallVectorImpl<unsigned> &Vals);
387   void writeOperandBundles(const CallBase &CB, unsigned InstID);
388   void pushValue(const Value *V, unsigned InstID,
389                  SmallVectorImpl<unsigned> &Vals);
390   void pushValueSigned(const Value *V, unsigned InstID,
391                        SmallVectorImpl<uint64_t> &Vals);
392   void writeInstruction(const Instruction &I, unsigned InstID,
393                         SmallVectorImpl<unsigned> &Vals);
394   void writeFunctionLevelValueSymbolTable(const ValueSymbolTable &VST);
395   void writeGlobalValueSymbolTable(
396       DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
397   void writeUseList(UseListOrder &&Order);
398   void writeUseListBlock(const Function *F);
399   void
400   writeFunction(const Function &F,
401                 DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
402   void writeBlockInfo();
403   void writeModuleHash(size_t BlockStartPos);
404 
405   unsigned getEncodedSyncScopeID(SyncScope::ID SSID) {
406     return unsigned(SSID);
407   }
408 
409   unsigned getEncodedAlign(MaybeAlign Alignment) { return encode(Alignment); }
410 };
411 
412 /// Class to manage the bitcode writing for a combined index.
413 class IndexBitcodeWriter : public BitcodeWriterBase {
414   /// The combined index to write to bitcode.
415   const ModuleSummaryIndex &Index;
416 
417   /// When writing a subset of the index for distributed backends, client
418   /// provides a map of modules to the corresponding GUIDs/summaries to write.
419   const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex;
420 
421   /// Map that holds the correspondence between the GUID used in the combined
422   /// index and a value id generated by this class to use in references.
423   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
424 
425   /// Tracks the last value id recorded in the GUIDToValueMap.
426   unsigned GlobalValueId = 0;
427 
428 public:
429   /// Constructs a IndexBitcodeWriter object for the given combined index,
430   /// writing to the provided \p Buffer. When writing a subset of the index
431   /// for a distributed backend, provide a \p ModuleToSummariesForIndex map.
432   IndexBitcodeWriter(BitstreamWriter &Stream, StringTableBuilder &StrtabBuilder,
433                      const ModuleSummaryIndex &Index,
434                      const std::map<std::string, GVSummaryMapTy>
435                          *ModuleToSummariesForIndex = nullptr)
436       : BitcodeWriterBase(Stream, StrtabBuilder), Index(Index),
437         ModuleToSummariesForIndex(ModuleToSummariesForIndex) {
438     // Assign unique value ids to all summaries to be written, for use
439     // in writing out the call graph edges. Save the mapping from GUID
440     // to the new global value id to use when writing those edges, which
441     // are currently saved in the index in terms of GUID.
442     forEachSummary([&](GVInfo I, bool) {
443       GUIDToValueIdMap[I.first] = ++GlobalValueId;
444     });
445   }
446 
447   /// The below iterator returns the GUID and associated summary.
448   using GVInfo = std::pair<GlobalValue::GUID, GlobalValueSummary *>;
449 
450   /// Calls the callback for each value GUID and summary to be written to
451   /// bitcode. This hides the details of whether they are being pulled from the
452   /// entire index or just those in a provided ModuleToSummariesForIndex map.
453   template<typename Functor>
454   void forEachSummary(Functor Callback) {
455     if (ModuleToSummariesForIndex) {
456       for (auto &M : *ModuleToSummariesForIndex)
457         for (auto &Summary : M.second) {
458           Callback(Summary, false);
459           // Ensure aliasee is handled, e.g. for assigning a valueId,
460           // even if we are not importing the aliasee directly (the
461           // imported alias will contain a copy of aliasee).
462           if (auto *AS = dyn_cast<AliasSummary>(Summary.getSecond()))
463             Callback({AS->getAliaseeGUID(), &AS->getAliasee()}, true);
464         }
465     } else {
466       for (auto &Summaries : Index)
467         for (auto &Summary : Summaries.second.SummaryList)
468           Callback({Summaries.first, Summary.get()}, false);
469     }
470   }
471 
472   /// Calls the callback for each entry in the modulePaths StringMap that
473   /// should be written to the module path string table. This hides the details
474   /// of whether they are being pulled from the entire index or just those in a
475   /// provided ModuleToSummariesForIndex map.
476   template <typename Functor> void forEachModule(Functor Callback) {
477     if (ModuleToSummariesForIndex) {
478       for (const auto &M : *ModuleToSummariesForIndex) {
479         const auto &MPI = Index.modulePaths().find(M.first);
480         if (MPI == Index.modulePaths().end()) {
481           // This should only happen if the bitcode file was empty, in which
482           // case we shouldn't be importing (the ModuleToSummariesForIndex
483           // would only include the module we are writing and index for).
484           assert(ModuleToSummariesForIndex->size() == 1);
485           continue;
486         }
487         Callback(*MPI);
488       }
489     } else {
490       for (const auto &MPSE : Index.modulePaths())
491         Callback(MPSE);
492     }
493   }
494 
495   /// Main entry point for writing a combined index to bitcode.
496   void write();
497 
498 private:
499   void writeModStrings();
500   void writeCombinedGlobalValueSummary();
501 
502   Optional<unsigned> getValueId(GlobalValue::GUID ValGUID) {
503     auto VMI = GUIDToValueIdMap.find(ValGUID);
504     if (VMI == GUIDToValueIdMap.end())
505       return None;
506     return VMI->second;
507   }
508 
509   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
510 };
511 
512 } // end anonymous namespace
513 
514 static unsigned getEncodedCastOpcode(unsigned Opcode) {
515   switch (Opcode) {
516   default: llvm_unreachable("Unknown cast instruction!");
517   case Instruction::Trunc   : return bitc::CAST_TRUNC;
518   case Instruction::ZExt    : return bitc::CAST_ZEXT;
519   case Instruction::SExt    : return bitc::CAST_SEXT;
520   case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
521   case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
522   case Instruction::UIToFP  : return bitc::CAST_UITOFP;
523   case Instruction::SIToFP  : return bitc::CAST_SITOFP;
524   case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
525   case Instruction::FPExt   : return bitc::CAST_FPEXT;
526   case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
527   case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
528   case Instruction::BitCast : return bitc::CAST_BITCAST;
529   case Instruction::AddrSpaceCast: return bitc::CAST_ADDRSPACECAST;
530   }
531 }
532 
533 static unsigned getEncodedUnaryOpcode(unsigned Opcode) {
534   switch (Opcode) {
535   default: llvm_unreachable("Unknown binary instruction!");
536   case Instruction::FNeg: return bitc::UNOP_FNEG;
537   }
538 }
539 
540 static unsigned getEncodedBinaryOpcode(unsigned Opcode) {
541   switch (Opcode) {
542   default: llvm_unreachable("Unknown binary instruction!");
543   case Instruction::Add:
544   case Instruction::FAdd: return bitc::BINOP_ADD;
545   case Instruction::Sub:
546   case Instruction::FSub: return bitc::BINOP_SUB;
547   case Instruction::Mul:
548   case Instruction::FMul: return bitc::BINOP_MUL;
549   case Instruction::UDiv: return bitc::BINOP_UDIV;
550   case Instruction::FDiv:
551   case Instruction::SDiv: return bitc::BINOP_SDIV;
552   case Instruction::URem: return bitc::BINOP_UREM;
553   case Instruction::FRem:
554   case Instruction::SRem: return bitc::BINOP_SREM;
555   case Instruction::Shl:  return bitc::BINOP_SHL;
556   case Instruction::LShr: return bitc::BINOP_LSHR;
557   case Instruction::AShr: return bitc::BINOP_ASHR;
558   case Instruction::And:  return bitc::BINOP_AND;
559   case Instruction::Or:   return bitc::BINOP_OR;
560   case Instruction::Xor:  return bitc::BINOP_XOR;
561   }
562 }
563 
564 static unsigned getEncodedRMWOperation(AtomicRMWInst::BinOp Op) {
565   switch (Op) {
566   default: llvm_unreachable("Unknown RMW operation!");
567   case AtomicRMWInst::Xchg: return bitc::RMW_XCHG;
568   case AtomicRMWInst::Add: return bitc::RMW_ADD;
569   case AtomicRMWInst::Sub: return bitc::RMW_SUB;
570   case AtomicRMWInst::And: return bitc::RMW_AND;
571   case AtomicRMWInst::Nand: return bitc::RMW_NAND;
572   case AtomicRMWInst::Or: return bitc::RMW_OR;
573   case AtomicRMWInst::Xor: return bitc::RMW_XOR;
574   case AtomicRMWInst::Max: return bitc::RMW_MAX;
575   case AtomicRMWInst::Min: return bitc::RMW_MIN;
576   case AtomicRMWInst::UMax: return bitc::RMW_UMAX;
577   case AtomicRMWInst::UMin: return bitc::RMW_UMIN;
578   case AtomicRMWInst::FAdd: return bitc::RMW_FADD;
579   case AtomicRMWInst::FSub: return bitc::RMW_FSUB;
580   case AtomicRMWInst::FMax: return bitc::RMW_FMAX;
581   case AtomicRMWInst::FMin: return bitc::RMW_FMIN;
582   }
583 }
584 
585 static unsigned getEncodedOrdering(AtomicOrdering Ordering) {
586   switch (Ordering) {
587   case AtomicOrdering::NotAtomic: return bitc::ORDERING_NOTATOMIC;
588   case AtomicOrdering::Unordered: return bitc::ORDERING_UNORDERED;
589   case AtomicOrdering::Monotonic: return bitc::ORDERING_MONOTONIC;
590   case AtomicOrdering::Acquire: return bitc::ORDERING_ACQUIRE;
591   case AtomicOrdering::Release: return bitc::ORDERING_RELEASE;
592   case AtomicOrdering::AcquireRelease: return bitc::ORDERING_ACQREL;
593   case AtomicOrdering::SequentiallyConsistent: return bitc::ORDERING_SEQCST;
594   }
595   llvm_unreachable("Invalid ordering");
596 }
597 
598 static void writeStringRecord(BitstreamWriter &Stream, unsigned Code,
599                               StringRef Str, unsigned AbbrevToUse) {
600   SmallVector<unsigned, 64> Vals;
601 
602   // Code: [strchar x N]
603   for (char C : Str) {
604     if (AbbrevToUse && !BitCodeAbbrevOp::isChar6(C))
605       AbbrevToUse = 0;
606     Vals.push_back(C);
607   }
608 
609   // Emit the finished record.
610   Stream.EmitRecord(Code, Vals, AbbrevToUse);
611 }
612 
613 static uint64_t getAttrKindEncoding(Attribute::AttrKind Kind) {
614   switch (Kind) {
615   case Attribute::Alignment:
616     return bitc::ATTR_KIND_ALIGNMENT;
617   case Attribute::AllocAlign:
618     return bitc::ATTR_KIND_ALLOC_ALIGN;
619   case Attribute::AllocSize:
620     return bitc::ATTR_KIND_ALLOC_SIZE;
621   case Attribute::AlwaysInline:
622     return bitc::ATTR_KIND_ALWAYS_INLINE;
623   case Attribute::ArgMemOnly:
624     return bitc::ATTR_KIND_ARGMEMONLY;
625   case Attribute::Builtin:
626     return bitc::ATTR_KIND_BUILTIN;
627   case Attribute::ByVal:
628     return bitc::ATTR_KIND_BY_VAL;
629   case Attribute::Convergent:
630     return bitc::ATTR_KIND_CONVERGENT;
631   case Attribute::InAlloca:
632     return bitc::ATTR_KIND_IN_ALLOCA;
633   case Attribute::Cold:
634     return bitc::ATTR_KIND_COLD;
635   case Attribute::DisableSanitizerInstrumentation:
636     return bitc::ATTR_KIND_DISABLE_SANITIZER_INSTRUMENTATION;
637   case Attribute::FnRetThunkExtern:
638     return bitc::ATTR_KIND_FNRETTHUNK_EXTERN;
639   case Attribute::Hot:
640     return bitc::ATTR_KIND_HOT;
641   case Attribute::ElementType:
642     return bitc::ATTR_KIND_ELEMENTTYPE;
643   case Attribute::InaccessibleMemOnly:
644     return bitc::ATTR_KIND_INACCESSIBLEMEM_ONLY;
645   case Attribute::InaccessibleMemOrArgMemOnly:
646     return bitc::ATTR_KIND_INACCESSIBLEMEM_OR_ARGMEMONLY;
647   case Attribute::InlineHint:
648     return bitc::ATTR_KIND_INLINE_HINT;
649   case Attribute::InReg:
650     return bitc::ATTR_KIND_IN_REG;
651   case Attribute::JumpTable:
652     return bitc::ATTR_KIND_JUMP_TABLE;
653   case Attribute::MinSize:
654     return bitc::ATTR_KIND_MIN_SIZE;
655   case Attribute::AllocatedPointer:
656     return bitc::ATTR_KIND_ALLOCATED_POINTER;
657   case Attribute::AllocKind:
658     return bitc::ATTR_KIND_ALLOC_KIND;
659   case Attribute::Naked:
660     return bitc::ATTR_KIND_NAKED;
661   case Attribute::Nest:
662     return bitc::ATTR_KIND_NEST;
663   case Attribute::NoAlias:
664     return bitc::ATTR_KIND_NO_ALIAS;
665   case Attribute::NoBuiltin:
666     return bitc::ATTR_KIND_NO_BUILTIN;
667   case Attribute::NoCallback:
668     return bitc::ATTR_KIND_NO_CALLBACK;
669   case Attribute::NoCapture:
670     return bitc::ATTR_KIND_NO_CAPTURE;
671   case Attribute::NoDuplicate:
672     return bitc::ATTR_KIND_NO_DUPLICATE;
673   case Attribute::NoFree:
674     return bitc::ATTR_KIND_NOFREE;
675   case Attribute::NoImplicitFloat:
676     return bitc::ATTR_KIND_NO_IMPLICIT_FLOAT;
677   case Attribute::NoInline:
678     return bitc::ATTR_KIND_NO_INLINE;
679   case Attribute::NoRecurse:
680     return bitc::ATTR_KIND_NO_RECURSE;
681   case Attribute::NoMerge:
682     return bitc::ATTR_KIND_NO_MERGE;
683   case Attribute::NonLazyBind:
684     return bitc::ATTR_KIND_NON_LAZY_BIND;
685   case Attribute::NonNull:
686     return bitc::ATTR_KIND_NON_NULL;
687   case Attribute::Dereferenceable:
688     return bitc::ATTR_KIND_DEREFERENCEABLE;
689   case Attribute::DereferenceableOrNull:
690     return bitc::ATTR_KIND_DEREFERENCEABLE_OR_NULL;
691   case Attribute::NoRedZone:
692     return bitc::ATTR_KIND_NO_RED_ZONE;
693   case Attribute::NoReturn:
694     return bitc::ATTR_KIND_NO_RETURN;
695   case Attribute::NoSync:
696     return bitc::ATTR_KIND_NOSYNC;
697   case Attribute::NoCfCheck:
698     return bitc::ATTR_KIND_NOCF_CHECK;
699   case Attribute::NoProfile:
700     return bitc::ATTR_KIND_NO_PROFILE;
701   case Attribute::SkipProfile:
702     return bitc::ATTR_KIND_SKIP_PROFILE;
703   case Attribute::NoUnwind:
704     return bitc::ATTR_KIND_NO_UNWIND;
705   case Attribute::NoSanitizeBounds:
706     return bitc::ATTR_KIND_NO_SANITIZE_BOUNDS;
707   case Attribute::NoSanitizeCoverage:
708     return bitc::ATTR_KIND_NO_SANITIZE_COVERAGE;
709   case Attribute::NullPointerIsValid:
710     return bitc::ATTR_KIND_NULL_POINTER_IS_VALID;
711   case Attribute::OptForFuzzing:
712     return bitc::ATTR_KIND_OPT_FOR_FUZZING;
713   case Attribute::OptimizeForSize:
714     return bitc::ATTR_KIND_OPTIMIZE_FOR_SIZE;
715   case Attribute::OptimizeNone:
716     return bitc::ATTR_KIND_OPTIMIZE_NONE;
717   case Attribute::ReadNone:
718     return bitc::ATTR_KIND_READ_NONE;
719   case Attribute::ReadOnly:
720     return bitc::ATTR_KIND_READ_ONLY;
721   case Attribute::Returned:
722     return bitc::ATTR_KIND_RETURNED;
723   case Attribute::ReturnsTwice:
724     return bitc::ATTR_KIND_RETURNS_TWICE;
725   case Attribute::SExt:
726     return bitc::ATTR_KIND_S_EXT;
727   case Attribute::Speculatable:
728     return bitc::ATTR_KIND_SPECULATABLE;
729   case Attribute::StackAlignment:
730     return bitc::ATTR_KIND_STACK_ALIGNMENT;
731   case Attribute::StackProtect:
732     return bitc::ATTR_KIND_STACK_PROTECT;
733   case Attribute::StackProtectReq:
734     return bitc::ATTR_KIND_STACK_PROTECT_REQ;
735   case Attribute::StackProtectStrong:
736     return bitc::ATTR_KIND_STACK_PROTECT_STRONG;
737   case Attribute::SafeStack:
738     return bitc::ATTR_KIND_SAFESTACK;
739   case Attribute::ShadowCallStack:
740     return bitc::ATTR_KIND_SHADOWCALLSTACK;
741   case Attribute::StrictFP:
742     return bitc::ATTR_KIND_STRICT_FP;
743   case Attribute::StructRet:
744     return bitc::ATTR_KIND_STRUCT_RET;
745   case Attribute::SanitizeAddress:
746     return bitc::ATTR_KIND_SANITIZE_ADDRESS;
747   case Attribute::SanitizeHWAddress:
748     return bitc::ATTR_KIND_SANITIZE_HWADDRESS;
749   case Attribute::SanitizeThread:
750     return bitc::ATTR_KIND_SANITIZE_THREAD;
751   case Attribute::SanitizeMemory:
752     return bitc::ATTR_KIND_SANITIZE_MEMORY;
753   case Attribute::SpeculativeLoadHardening:
754     return bitc::ATTR_KIND_SPECULATIVE_LOAD_HARDENING;
755   case Attribute::SwiftError:
756     return bitc::ATTR_KIND_SWIFT_ERROR;
757   case Attribute::SwiftSelf:
758     return bitc::ATTR_KIND_SWIFT_SELF;
759   case Attribute::SwiftAsync:
760     return bitc::ATTR_KIND_SWIFT_ASYNC;
761   case Attribute::UWTable:
762     return bitc::ATTR_KIND_UW_TABLE;
763   case Attribute::VScaleRange:
764     return bitc::ATTR_KIND_VSCALE_RANGE;
765   case Attribute::WillReturn:
766     return bitc::ATTR_KIND_WILLRETURN;
767   case Attribute::WriteOnly:
768     return bitc::ATTR_KIND_WRITEONLY;
769   case Attribute::ZExt:
770     return bitc::ATTR_KIND_Z_EXT;
771   case Attribute::ImmArg:
772     return bitc::ATTR_KIND_IMMARG;
773   case Attribute::SanitizeMemTag:
774     return bitc::ATTR_KIND_SANITIZE_MEMTAG;
775   case Attribute::Preallocated:
776     return bitc::ATTR_KIND_PREALLOCATED;
777   case Attribute::NoUndef:
778     return bitc::ATTR_KIND_NOUNDEF;
779   case Attribute::ByRef:
780     return bitc::ATTR_KIND_BYREF;
781   case Attribute::MustProgress:
782     return bitc::ATTR_KIND_MUSTPROGRESS;
783   case Attribute::PresplitCoroutine:
784     return bitc::ATTR_KIND_PRESPLIT_COROUTINE;
785   case Attribute::EndAttrKinds:
786     llvm_unreachable("Can not encode end-attribute kinds marker.");
787   case Attribute::None:
788     llvm_unreachable("Can not encode none-attribute.");
789   case Attribute::EmptyKey:
790   case Attribute::TombstoneKey:
791     llvm_unreachable("Trying to encode EmptyKey/TombstoneKey");
792   }
793 
794   llvm_unreachable("Trying to encode unknown attribute");
795 }
796 
797 void ModuleBitcodeWriter::writeAttributeGroupTable() {
798   const std::vector<ValueEnumerator::IndexAndAttrSet> &AttrGrps =
799       VE.getAttributeGroups();
800   if (AttrGrps.empty()) return;
801 
802   Stream.EnterSubblock(bitc::PARAMATTR_GROUP_BLOCK_ID, 3);
803 
804   SmallVector<uint64_t, 64> Record;
805   for (ValueEnumerator::IndexAndAttrSet Pair : AttrGrps) {
806     unsigned AttrListIndex = Pair.first;
807     AttributeSet AS = Pair.second;
808     Record.push_back(VE.getAttributeGroupID(Pair));
809     Record.push_back(AttrListIndex);
810 
811     for (Attribute Attr : AS) {
812       if (Attr.isEnumAttribute()) {
813         Record.push_back(0);
814         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
815       } else if (Attr.isIntAttribute()) {
816         Record.push_back(1);
817         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
818         Record.push_back(Attr.getValueAsInt());
819       } else if (Attr.isStringAttribute()) {
820         StringRef Kind = Attr.getKindAsString();
821         StringRef Val = Attr.getValueAsString();
822 
823         Record.push_back(Val.empty() ? 3 : 4);
824         Record.append(Kind.begin(), Kind.end());
825         Record.push_back(0);
826         if (!Val.empty()) {
827           Record.append(Val.begin(), Val.end());
828           Record.push_back(0);
829         }
830       } else {
831         assert(Attr.isTypeAttribute());
832         Type *Ty = Attr.getValueAsType();
833         Record.push_back(Ty ? 6 : 5);
834         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
835         if (Ty)
836           Record.push_back(VE.getTypeID(Attr.getValueAsType()));
837       }
838     }
839 
840     Stream.EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
841     Record.clear();
842   }
843 
844   Stream.ExitBlock();
845 }
846 
847 void ModuleBitcodeWriter::writeAttributeTable() {
848   const std::vector<AttributeList> &Attrs = VE.getAttributeLists();
849   if (Attrs.empty()) return;
850 
851   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
852 
853   SmallVector<uint64_t, 64> Record;
854   for (const AttributeList &AL : Attrs) {
855     for (unsigned i : AL.indexes()) {
856       AttributeSet AS = AL.getAttributes(i);
857       if (AS.hasAttributes())
858         Record.push_back(VE.getAttributeGroupID({i, AS}));
859     }
860 
861     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
862     Record.clear();
863   }
864 
865   Stream.ExitBlock();
866 }
867 
868 /// WriteTypeTable - Write out the type table for a module.
869 void ModuleBitcodeWriter::writeTypeTable() {
870   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
871 
872   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
873   SmallVector<uint64_t, 64> TypeVals;
874 
875   uint64_t NumBits = VE.computeBitsRequiredForTypeIndicies();
876 
877   // Abbrev for TYPE_CODE_POINTER.
878   auto Abbv = std::make_shared<BitCodeAbbrev>();
879   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
880   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
881   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
882   unsigned PtrAbbrev = Stream.EmitAbbrev(std::move(Abbv));
883 
884   // Abbrev for TYPE_CODE_OPAQUE_POINTER.
885   Abbv = std::make_shared<BitCodeAbbrev>();
886   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_OPAQUE_POINTER));
887   Abbv->Add(BitCodeAbbrevOp(0)); // Addrspace = 0
888   unsigned OpaquePtrAbbrev = Stream.EmitAbbrev(std::move(Abbv));
889 
890   // Abbrev for TYPE_CODE_FUNCTION.
891   Abbv = std::make_shared<BitCodeAbbrev>();
892   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
893   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
894   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
895   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
896   unsigned FunctionAbbrev = Stream.EmitAbbrev(std::move(Abbv));
897 
898   // Abbrev for TYPE_CODE_STRUCT_ANON.
899   Abbv = std::make_shared<BitCodeAbbrev>();
900   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
901   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
902   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
903   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
904   unsigned StructAnonAbbrev = Stream.EmitAbbrev(std::move(Abbv));
905 
906   // Abbrev for TYPE_CODE_STRUCT_NAME.
907   Abbv = std::make_shared<BitCodeAbbrev>();
908   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
909   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
910   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
911   unsigned StructNameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
912 
913   // Abbrev for TYPE_CODE_STRUCT_NAMED.
914   Abbv = std::make_shared<BitCodeAbbrev>();
915   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
916   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
917   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
918   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
919   unsigned StructNamedAbbrev = Stream.EmitAbbrev(std::move(Abbv));
920 
921   // Abbrev for TYPE_CODE_ARRAY.
922   Abbv = std::make_shared<BitCodeAbbrev>();
923   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
924   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
925   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
926   unsigned ArrayAbbrev = Stream.EmitAbbrev(std::move(Abbv));
927 
928   // Emit an entry count so the reader can reserve space.
929   TypeVals.push_back(TypeList.size());
930   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
931   TypeVals.clear();
932 
933   // Loop over all of the types, emitting each in turn.
934   for (Type *T : TypeList) {
935     int AbbrevToUse = 0;
936     unsigned Code = 0;
937 
938     switch (T->getTypeID()) {
939     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;      break;
940     case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;      break;
941     case Type::BFloatTyID:    Code = bitc::TYPE_CODE_BFLOAT;    break;
942     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;     break;
943     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE;    break;
944     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80;  break;
945     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128;     break;
946     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
947     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;     break;
948     case Type::MetadataTyID:  Code = bitc::TYPE_CODE_METADATA;  break;
949     case Type::X86_MMXTyID:   Code = bitc::TYPE_CODE_X86_MMX;   break;
950     case Type::X86_AMXTyID:   Code = bitc::TYPE_CODE_X86_AMX;   break;
951     case Type::TokenTyID:     Code = bitc::TYPE_CODE_TOKEN;     break;
952     case Type::IntegerTyID:
953       // INTEGER: [width]
954       Code = bitc::TYPE_CODE_INTEGER;
955       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
956       break;
957     case Type::PointerTyID: {
958       PointerType *PTy = cast<PointerType>(T);
959       unsigned AddressSpace = PTy->getAddressSpace();
960       if (PTy->isOpaque()) {
961         // OPAQUE_POINTER: [address space]
962         Code = bitc::TYPE_CODE_OPAQUE_POINTER;
963         TypeVals.push_back(AddressSpace);
964         if (AddressSpace == 0)
965           AbbrevToUse = OpaquePtrAbbrev;
966       } else {
967         // POINTER: [pointee type, address space]
968         Code = bitc::TYPE_CODE_POINTER;
969         TypeVals.push_back(VE.getTypeID(PTy->getNonOpaquePointerElementType()));
970         TypeVals.push_back(AddressSpace);
971         if (AddressSpace == 0)
972           AbbrevToUse = PtrAbbrev;
973       }
974       break;
975     }
976     case Type::FunctionTyID: {
977       FunctionType *FT = cast<FunctionType>(T);
978       // FUNCTION: [isvararg, retty, paramty x N]
979       Code = bitc::TYPE_CODE_FUNCTION;
980       TypeVals.push_back(FT->isVarArg());
981       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
982       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
983         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
984       AbbrevToUse = FunctionAbbrev;
985       break;
986     }
987     case Type::StructTyID: {
988       StructType *ST = cast<StructType>(T);
989       // STRUCT: [ispacked, eltty x N]
990       TypeVals.push_back(ST->isPacked());
991       // Output all of the element types.
992       for (Type *ET : ST->elements())
993         TypeVals.push_back(VE.getTypeID(ET));
994 
995       if (ST->isLiteral()) {
996         Code = bitc::TYPE_CODE_STRUCT_ANON;
997         AbbrevToUse = StructAnonAbbrev;
998       } else {
999         if (ST->isOpaque()) {
1000           Code = bitc::TYPE_CODE_OPAQUE;
1001         } else {
1002           Code = bitc::TYPE_CODE_STRUCT_NAMED;
1003           AbbrevToUse = StructNamedAbbrev;
1004         }
1005 
1006         // Emit the name if it is present.
1007         if (!ST->getName().empty())
1008           writeStringRecord(Stream, bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
1009                             StructNameAbbrev);
1010       }
1011       break;
1012     }
1013     case Type::ArrayTyID: {
1014       ArrayType *AT = cast<ArrayType>(T);
1015       // ARRAY: [numelts, eltty]
1016       Code = bitc::TYPE_CODE_ARRAY;
1017       TypeVals.push_back(AT->getNumElements());
1018       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
1019       AbbrevToUse = ArrayAbbrev;
1020       break;
1021     }
1022     case Type::FixedVectorTyID:
1023     case Type::ScalableVectorTyID: {
1024       VectorType *VT = cast<VectorType>(T);
1025       // VECTOR [numelts, eltty] or
1026       //        [numelts, eltty, scalable]
1027       Code = bitc::TYPE_CODE_VECTOR;
1028       TypeVals.push_back(VT->getElementCount().getKnownMinValue());
1029       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
1030       if (isa<ScalableVectorType>(VT))
1031         TypeVals.push_back(true);
1032       break;
1033     }
1034     case Type::TypedPointerTyID:
1035       llvm_unreachable("Typed pointers cannot be added to IR modules");
1036     }
1037 
1038     // Emit the finished record.
1039     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
1040     TypeVals.clear();
1041   }
1042 
1043   Stream.ExitBlock();
1044 }
1045 
1046 static unsigned getEncodedLinkage(const GlobalValue::LinkageTypes Linkage) {
1047   switch (Linkage) {
1048   case GlobalValue::ExternalLinkage:
1049     return 0;
1050   case GlobalValue::WeakAnyLinkage:
1051     return 16;
1052   case GlobalValue::AppendingLinkage:
1053     return 2;
1054   case GlobalValue::InternalLinkage:
1055     return 3;
1056   case GlobalValue::LinkOnceAnyLinkage:
1057     return 18;
1058   case GlobalValue::ExternalWeakLinkage:
1059     return 7;
1060   case GlobalValue::CommonLinkage:
1061     return 8;
1062   case GlobalValue::PrivateLinkage:
1063     return 9;
1064   case GlobalValue::WeakODRLinkage:
1065     return 17;
1066   case GlobalValue::LinkOnceODRLinkage:
1067     return 19;
1068   case GlobalValue::AvailableExternallyLinkage:
1069     return 12;
1070   }
1071   llvm_unreachable("Invalid linkage");
1072 }
1073 
1074 static unsigned getEncodedLinkage(const GlobalValue &GV) {
1075   return getEncodedLinkage(GV.getLinkage());
1076 }
1077 
1078 static uint64_t getEncodedFFlags(FunctionSummary::FFlags Flags) {
1079   uint64_t RawFlags = 0;
1080   RawFlags |= Flags.ReadNone;
1081   RawFlags |= (Flags.ReadOnly << 1);
1082   RawFlags |= (Flags.NoRecurse << 2);
1083   RawFlags |= (Flags.ReturnDoesNotAlias << 3);
1084   RawFlags |= (Flags.NoInline << 4);
1085   RawFlags |= (Flags.AlwaysInline << 5);
1086   RawFlags |= (Flags.NoUnwind << 6);
1087   RawFlags |= (Flags.MayThrow << 7);
1088   RawFlags |= (Flags.HasUnknownCall << 8);
1089   RawFlags |= (Flags.MustBeUnreachable << 9);
1090   return RawFlags;
1091 }
1092 
1093 // Decode the flags for GlobalValue in the summary. See getDecodedGVSummaryFlags
1094 // in BitcodeReader.cpp.
1095 static uint64_t getEncodedGVSummaryFlags(GlobalValueSummary::GVFlags Flags) {
1096   uint64_t RawFlags = 0;
1097 
1098   RawFlags |= Flags.NotEligibleToImport; // bool
1099   RawFlags |= (Flags.Live << 1);
1100   RawFlags |= (Flags.DSOLocal << 2);
1101   RawFlags |= (Flags.CanAutoHide << 3);
1102 
1103   // Linkage don't need to be remapped at that time for the summary. Any future
1104   // change to the getEncodedLinkage() function will need to be taken into
1105   // account here as well.
1106   RawFlags = (RawFlags << 4) | Flags.Linkage; // 4 bits
1107 
1108   RawFlags |= (Flags.Visibility << 8); // 2 bits
1109 
1110   return RawFlags;
1111 }
1112 
1113 static uint64_t getEncodedGVarFlags(GlobalVarSummary::GVarFlags Flags) {
1114   uint64_t RawFlags = Flags.MaybeReadOnly | (Flags.MaybeWriteOnly << 1) |
1115                       (Flags.Constant << 2) | Flags.VCallVisibility << 3;
1116   return RawFlags;
1117 }
1118 
1119 static unsigned getEncodedVisibility(const GlobalValue &GV) {
1120   switch (GV.getVisibility()) {
1121   case GlobalValue::DefaultVisibility:   return 0;
1122   case GlobalValue::HiddenVisibility:    return 1;
1123   case GlobalValue::ProtectedVisibility: return 2;
1124   }
1125   llvm_unreachable("Invalid visibility");
1126 }
1127 
1128 static unsigned getEncodedDLLStorageClass(const GlobalValue &GV) {
1129   switch (GV.getDLLStorageClass()) {
1130   case GlobalValue::DefaultStorageClass:   return 0;
1131   case GlobalValue::DLLImportStorageClass: return 1;
1132   case GlobalValue::DLLExportStorageClass: return 2;
1133   }
1134   llvm_unreachable("Invalid DLL storage class");
1135 }
1136 
1137 static unsigned getEncodedThreadLocalMode(const GlobalValue &GV) {
1138   switch (GV.getThreadLocalMode()) {
1139     case GlobalVariable::NotThreadLocal:         return 0;
1140     case GlobalVariable::GeneralDynamicTLSModel: return 1;
1141     case GlobalVariable::LocalDynamicTLSModel:   return 2;
1142     case GlobalVariable::InitialExecTLSModel:    return 3;
1143     case GlobalVariable::LocalExecTLSModel:      return 4;
1144   }
1145   llvm_unreachable("Invalid TLS model");
1146 }
1147 
1148 static unsigned getEncodedComdatSelectionKind(const Comdat &C) {
1149   switch (C.getSelectionKind()) {
1150   case Comdat::Any:
1151     return bitc::COMDAT_SELECTION_KIND_ANY;
1152   case Comdat::ExactMatch:
1153     return bitc::COMDAT_SELECTION_KIND_EXACT_MATCH;
1154   case Comdat::Largest:
1155     return bitc::COMDAT_SELECTION_KIND_LARGEST;
1156   case Comdat::NoDeduplicate:
1157     return bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES;
1158   case Comdat::SameSize:
1159     return bitc::COMDAT_SELECTION_KIND_SAME_SIZE;
1160   }
1161   llvm_unreachable("Invalid selection kind");
1162 }
1163 
1164 static unsigned getEncodedUnnamedAddr(const GlobalValue &GV) {
1165   switch (GV.getUnnamedAddr()) {
1166   case GlobalValue::UnnamedAddr::None:   return 0;
1167   case GlobalValue::UnnamedAddr::Local:  return 2;
1168   case GlobalValue::UnnamedAddr::Global: return 1;
1169   }
1170   llvm_unreachable("Invalid unnamed_addr");
1171 }
1172 
1173 size_t ModuleBitcodeWriter::addToStrtab(StringRef Str) {
1174   if (GenerateHash)
1175     Hasher.update(Str);
1176   return StrtabBuilder.add(Str);
1177 }
1178 
1179 void ModuleBitcodeWriter::writeComdats() {
1180   SmallVector<unsigned, 64> Vals;
1181   for (const Comdat *C : VE.getComdats()) {
1182     // COMDAT: [strtab offset, strtab size, selection_kind]
1183     Vals.push_back(addToStrtab(C->getName()));
1184     Vals.push_back(C->getName().size());
1185     Vals.push_back(getEncodedComdatSelectionKind(*C));
1186     Stream.EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
1187     Vals.clear();
1188   }
1189 }
1190 
1191 /// Write a record that will eventually hold the word offset of the
1192 /// module-level VST. For now the offset is 0, which will be backpatched
1193 /// after the real VST is written. Saves the bit offset to backpatch.
1194 void ModuleBitcodeWriter::writeValueSymbolTableForwardDecl() {
1195   // Write a placeholder value in for the offset of the real VST,
1196   // which is written after the function blocks so that it can include
1197   // the offset of each function. The placeholder offset will be
1198   // updated when the real VST is written.
1199   auto Abbv = std::make_shared<BitCodeAbbrev>();
1200   Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_VSTOFFSET));
1201   // Blocks are 32-bit aligned, so we can use a 32-bit word offset to
1202   // hold the real VST offset. Must use fixed instead of VBR as we don't
1203   // know how many VBR chunks to reserve ahead of time.
1204   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
1205   unsigned VSTOffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1206 
1207   // Emit the placeholder
1208   uint64_t Vals[] = {bitc::MODULE_CODE_VSTOFFSET, 0};
1209   Stream.EmitRecordWithAbbrev(VSTOffsetAbbrev, Vals);
1210 
1211   // Compute and save the bit offset to the placeholder, which will be
1212   // patched when the real VST is written. We can simply subtract the 32-bit
1213   // fixed size from the current bit number to get the location to backpatch.
1214   VSTOffsetPlaceholder = Stream.GetCurrentBitNo() - 32;
1215 }
1216 
1217 enum StringEncoding { SE_Char6, SE_Fixed7, SE_Fixed8 };
1218 
1219 /// Determine the encoding to use for the given string name and length.
1220 static StringEncoding getStringEncoding(StringRef Str) {
1221   bool isChar6 = true;
1222   for (char C : Str) {
1223     if (isChar6)
1224       isChar6 = BitCodeAbbrevOp::isChar6(C);
1225     if ((unsigned char)C & 128)
1226       // don't bother scanning the rest.
1227       return SE_Fixed8;
1228   }
1229   if (isChar6)
1230     return SE_Char6;
1231   return SE_Fixed7;
1232 }
1233 
1234 static_assert(sizeof(GlobalValue::SanitizerMetadata) <= sizeof(unsigned),
1235               "Sanitizer Metadata is too large for naive serialization.");
1236 static unsigned
1237 serializeSanitizerMetadata(const GlobalValue::SanitizerMetadata &Meta) {
1238   return Meta.NoAddress | (Meta.NoHWAddress << 1) |
1239          (Meta.Memtag << 2) | (Meta.IsDynInit << 3);
1240 }
1241 
1242 /// Emit top-level description of module, including target triple, inline asm,
1243 /// descriptors for global variables, and function prototype info.
1244 /// Returns the bit offset to backpatch with the location of the real VST.
1245 void ModuleBitcodeWriter::writeModuleInfo() {
1246   // Emit various pieces of data attached to a module.
1247   if (!M.getTargetTriple().empty())
1248     writeStringRecord(Stream, bitc::MODULE_CODE_TRIPLE, M.getTargetTriple(),
1249                       0 /*TODO*/);
1250   const std::string &DL = M.getDataLayoutStr();
1251   if (!DL.empty())
1252     writeStringRecord(Stream, bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/);
1253   if (!M.getModuleInlineAsm().empty())
1254     writeStringRecord(Stream, bitc::MODULE_CODE_ASM, M.getModuleInlineAsm(),
1255                       0 /*TODO*/);
1256 
1257   // Emit information about sections and GC, computing how many there are. Also
1258   // compute the maximum alignment value.
1259   std::map<std::string, unsigned> SectionMap;
1260   std::map<std::string, unsigned> GCMap;
1261   MaybeAlign MaxAlignment;
1262   unsigned MaxGlobalType = 0;
1263   const auto UpdateMaxAlignment = [&MaxAlignment](const MaybeAlign A) {
1264     if (A)
1265       MaxAlignment = !MaxAlignment ? *A : std::max(*MaxAlignment, *A);
1266   };
1267   for (const GlobalVariable &GV : M.globals()) {
1268     UpdateMaxAlignment(GV.getAlign());
1269     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getValueType()));
1270     if (GV.hasSection()) {
1271       // Give section names unique ID's.
1272       unsigned &Entry = SectionMap[std::string(GV.getSection())];
1273       if (!Entry) {
1274         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
1275                           0 /*TODO*/);
1276         Entry = SectionMap.size();
1277       }
1278     }
1279   }
1280   for (const Function &F : M) {
1281     UpdateMaxAlignment(F.getAlign());
1282     if (F.hasSection()) {
1283       // Give section names unique ID's.
1284       unsigned &Entry = SectionMap[std::string(F.getSection())];
1285       if (!Entry) {
1286         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
1287                           0 /*TODO*/);
1288         Entry = SectionMap.size();
1289       }
1290     }
1291     if (F.hasGC()) {
1292       // Same for GC names.
1293       unsigned &Entry = GCMap[F.getGC()];
1294       if (!Entry) {
1295         writeStringRecord(Stream, bitc::MODULE_CODE_GCNAME, F.getGC(),
1296                           0 /*TODO*/);
1297         Entry = GCMap.size();
1298       }
1299     }
1300   }
1301 
1302   // Emit abbrev for globals, now that we know # sections and max alignment.
1303   unsigned SimpleGVarAbbrev = 0;
1304   if (!M.global_empty()) {
1305     // Add an abbrev for common globals with no visibility or thread localness.
1306     auto Abbv = std::make_shared<BitCodeAbbrev>();
1307     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
1308     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1309     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1310     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1311                               Log2_32_Ceil(MaxGlobalType+1)));
1312     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddrSpace << 2
1313                                                            //| explicitType << 1
1314                                                            //| constant
1315     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Initializer.
1316     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // Linkage.
1317     if (!MaxAlignment)                                     // Alignment.
1318       Abbv->Add(BitCodeAbbrevOp(0));
1319     else {
1320       unsigned MaxEncAlignment = getEncodedAlign(MaxAlignment);
1321       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1322                                Log2_32_Ceil(MaxEncAlignment+1)));
1323     }
1324     if (SectionMap.empty())                                    // Section.
1325       Abbv->Add(BitCodeAbbrevOp(0));
1326     else
1327       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1328                                Log2_32_Ceil(SectionMap.size()+1)));
1329     // Don't bother emitting vis + thread local.
1330     SimpleGVarAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1331   }
1332 
1333   SmallVector<unsigned, 64> Vals;
1334   // Emit the module's source file name.
1335   {
1336     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
1337     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
1338     if (Bits == SE_Char6)
1339       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
1340     else if (Bits == SE_Fixed7)
1341       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
1342 
1343     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
1344     auto Abbv = std::make_shared<BitCodeAbbrev>();
1345     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
1346     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1347     Abbv->Add(AbbrevOpToUse);
1348     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1349 
1350     for (const auto P : M.getSourceFileName())
1351       Vals.push_back((unsigned char)P);
1352 
1353     // Emit the finished record.
1354     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
1355     Vals.clear();
1356   }
1357 
1358   // Emit the global variable information.
1359   for (const GlobalVariable &GV : M.globals()) {
1360     unsigned AbbrevToUse = 0;
1361 
1362     // GLOBALVAR: [strtab offset, strtab size, type, isconst, initid,
1363     //             linkage, alignment, section, visibility, threadlocal,
1364     //             unnamed_addr, externally_initialized, dllstorageclass,
1365     //             comdat, attributes, DSO_Local, GlobalSanitizer]
1366     Vals.push_back(addToStrtab(GV.getName()));
1367     Vals.push_back(GV.getName().size());
1368     Vals.push_back(VE.getTypeID(GV.getValueType()));
1369     Vals.push_back(GV.getType()->getAddressSpace() << 2 | 2 | GV.isConstant());
1370     Vals.push_back(GV.isDeclaration() ? 0 :
1371                    (VE.getValueID(GV.getInitializer()) + 1));
1372     Vals.push_back(getEncodedLinkage(GV));
1373     Vals.push_back(getEncodedAlign(GV.getAlign()));
1374     Vals.push_back(GV.hasSection() ? SectionMap[std::string(GV.getSection())]
1375                                    : 0);
1376     if (GV.isThreadLocal() ||
1377         GV.getVisibility() != GlobalValue::DefaultVisibility ||
1378         GV.getUnnamedAddr() != GlobalValue::UnnamedAddr::None ||
1379         GV.isExternallyInitialized() ||
1380         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
1381         GV.hasComdat() || GV.hasAttributes() || GV.isDSOLocal() ||
1382         GV.hasPartition() || GV.hasSanitizerMetadata()) {
1383       Vals.push_back(getEncodedVisibility(GV));
1384       Vals.push_back(getEncodedThreadLocalMode(GV));
1385       Vals.push_back(getEncodedUnnamedAddr(GV));
1386       Vals.push_back(GV.isExternallyInitialized());
1387       Vals.push_back(getEncodedDLLStorageClass(GV));
1388       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
1389 
1390       auto AL = GV.getAttributesAsList(AttributeList::FunctionIndex);
1391       Vals.push_back(VE.getAttributeListID(AL));
1392 
1393       Vals.push_back(GV.isDSOLocal());
1394       Vals.push_back(addToStrtab(GV.getPartition()));
1395       Vals.push_back(GV.getPartition().size());
1396 
1397       Vals.push_back((GV.hasSanitizerMetadata() ? serializeSanitizerMetadata(
1398                                                       GV.getSanitizerMetadata())
1399                                                 : 0));
1400     } else {
1401       AbbrevToUse = SimpleGVarAbbrev;
1402     }
1403 
1404     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
1405     Vals.clear();
1406   }
1407 
1408   // Emit the function proto information.
1409   for (const Function &F : M) {
1410     // FUNCTION:  [strtab offset, strtab size, type, callingconv, isproto,
1411     //             linkage, paramattrs, alignment, section, visibility, gc,
1412     //             unnamed_addr, prologuedata, dllstorageclass, comdat,
1413     //             prefixdata, personalityfn, DSO_Local, addrspace]
1414     Vals.push_back(addToStrtab(F.getName()));
1415     Vals.push_back(F.getName().size());
1416     Vals.push_back(VE.getTypeID(F.getFunctionType()));
1417     Vals.push_back(F.getCallingConv());
1418     Vals.push_back(F.isDeclaration());
1419     Vals.push_back(getEncodedLinkage(F));
1420     Vals.push_back(VE.getAttributeListID(F.getAttributes()));
1421     Vals.push_back(getEncodedAlign(F.getAlign()));
1422     Vals.push_back(F.hasSection() ? SectionMap[std::string(F.getSection())]
1423                                   : 0);
1424     Vals.push_back(getEncodedVisibility(F));
1425     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
1426     Vals.push_back(getEncodedUnnamedAddr(F));
1427     Vals.push_back(F.hasPrologueData() ? (VE.getValueID(F.getPrologueData()) + 1)
1428                                        : 0);
1429     Vals.push_back(getEncodedDLLStorageClass(F));
1430     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
1431     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
1432                                      : 0);
1433     Vals.push_back(
1434         F.hasPersonalityFn() ? (VE.getValueID(F.getPersonalityFn()) + 1) : 0);
1435 
1436     Vals.push_back(F.isDSOLocal());
1437     Vals.push_back(F.getAddressSpace());
1438     Vals.push_back(addToStrtab(F.getPartition()));
1439     Vals.push_back(F.getPartition().size());
1440 
1441     unsigned AbbrevToUse = 0;
1442     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
1443     Vals.clear();
1444   }
1445 
1446   // Emit the alias information.
1447   for (const GlobalAlias &A : M.aliases()) {
1448     // ALIAS: [strtab offset, strtab size, alias type, aliasee val#, linkage,
1449     //         visibility, dllstorageclass, threadlocal, unnamed_addr,
1450     //         DSO_Local]
1451     Vals.push_back(addToStrtab(A.getName()));
1452     Vals.push_back(A.getName().size());
1453     Vals.push_back(VE.getTypeID(A.getValueType()));
1454     Vals.push_back(A.getType()->getAddressSpace());
1455     Vals.push_back(VE.getValueID(A.getAliasee()));
1456     Vals.push_back(getEncodedLinkage(A));
1457     Vals.push_back(getEncodedVisibility(A));
1458     Vals.push_back(getEncodedDLLStorageClass(A));
1459     Vals.push_back(getEncodedThreadLocalMode(A));
1460     Vals.push_back(getEncodedUnnamedAddr(A));
1461     Vals.push_back(A.isDSOLocal());
1462     Vals.push_back(addToStrtab(A.getPartition()));
1463     Vals.push_back(A.getPartition().size());
1464 
1465     unsigned AbbrevToUse = 0;
1466     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
1467     Vals.clear();
1468   }
1469 
1470   // Emit the ifunc information.
1471   for (const GlobalIFunc &I : M.ifuncs()) {
1472     // IFUNC: [strtab offset, strtab size, ifunc type, address space, resolver
1473     //         val#, linkage, visibility, DSO_Local]
1474     Vals.push_back(addToStrtab(I.getName()));
1475     Vals.push_back(I.getName().size());
1476     Vals.push_back(VE.getTypeID(I.getValueType()));
1477     Vals.push_back(I.getType()->getAddressSpace());
1478     Vals.push_back(VE.getValueID(I.getResolver()));
1479     Vals.push_back(getEncodedLinkage(I));
1480     Vals.push_back(getEncodedVisibility(I));
1481     Vals.push_back(I.isDSOLocal());
1482     Vals.push_back(addToStrtab(I.getPartition()));
1483     Vals.push_back(I.getPartition().size());
1484     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
1485     Vals.clear();
1486   }
1487 
1488   writeValueSymbolTableForwardDecl();
1489 }
1490 
1491 static uint64_t getOptimizationFlags(const Value *V) {
1492   uint64_t Flags = 0;
1493 
1494   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
1495     if (OBO->hasNoSignedWrap())
1496       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
1497     if (OBO->hasNoUnsignedWrap())
1498       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
1499   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
1500     if (PEO->isExact())
1501       Flags |= 1 << bitc::PEO_EXACT;
1502   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
1503     if (FPMO->hasAllowReassoc())
1504       Flags |= bitc::AllowReassoc;
1505     if (FPMO->hasNoNaNs())
1506       Flags |= bitc::NoNaNs;
1507     if (FPMO->hasNoInfs())
1508       Flags |= bitc::NoInfs;
1509     if (FPMO->hasNoSignedZeros())
1510       Flags |= bitc::NoSignedZeros;
1511     if (FPMO->hasAllowReciprocal())
1512       Flags |= bitc::AllowReciprocal;
1513     if (FPMO->hasAllowContract())
1514       Flags |= bitc::AllowContract;
1515     if (FPMO->hasApproxFunc())
1516       Flags |= bitc::ApproxFunc;
1517   }
1518 
1519   return Flags;
1520 }
1521 
1522 void ModuleBitcodeWriter::writeValueAsMetadata(
1523     const ValueAsMetadata *MD, SmallVectorImpl<uint64_t> &Record) {
1524   // Mimic an MDNode with a value as one operand.
1525   Value *V = MD->getValue();
1526   Record.push_back(VE.getTypeID(V->getType()));
1527   Record.push_back(VE.getValueID(V));
1528   Stream.EmitRecord(bitc::METADATA_VALUE, Record, 0);
1529   Record.clear();
1530 }
1531 
1532 void ModuleBitcodeWriter::writeMDTuple(const MDTuple *N,
1533                                        SmallVectorImpl<uint64_t> &Record,
1534                                        unsigned Abbrev) {
1535   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
1536     Metadata *MD = N->getOperand(i);
1537     assert(!(MD && isa<LocalAsMetadata>(MD)) &&
1538            "Unexpected function-local metadata");
1539     Record.push_back(VE.getMetadataOrNullID(MD));
1540   }
1541   Stream.EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
1542                                     : bitc::METADATA_NODE,
1543                     Record, Abbrev);
1544   Record.clear();
1545 }
1546 
1547 unsigned ModuleBitcodeWriter::createDILocationAbbrev() {
1548   // Assume the column is usually under 128, and always output the inlined-at
1549   // location (it's never more expensive than building an array size 1).
1550   auto Abbv = std::make_shared<BitCodeAbbrev>();
1551   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
1552   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1553   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1554   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1555   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1556   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1557   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1558   return Stream.EmitAbbrev(std::move(Abbv));
1559 }
1560 
1561 void ModuleBitcodeWriter::writeDILocation(const DILocation *N,
1562                                           SmallVectorImpl<uint64_t> &Record,
1563                                           unsigned &Abbrev) {
1564   if (!Abbrev)
1565     Abbrev = createDILocationAbbrev();
1566 
1567   Record.push_back(N->isDistinct());
1568   Record.push_back(N->getLine());
1569   Record.push_back(N->getColumn());
1570   Record.push_back(VE.getMetadataID(N->getScope()));
1571   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
1572   Record.push_back(N->isImplicitCode());
1573 
1574   Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
1575   Record.clear();
1576 }
1577 
1578 unsigned ModuleBitcodeWriter::createGenericDINodeAbbrev() {
1579   // Assume the column is usually under 128, and always output the inlined-at
1580   // location (it's never more expensive than building an array size 1).
1581   auto Abbv = std::make_shared<BitCodeAbbrev>();
1582   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
1583   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1584   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1585   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1586   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1587   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1588   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1589   return Stream.EmitAbbrev(std::move(Abbv));
1590 }
1591 
1592 void ModuleBitcodeWriter::writeGenericDINode(const GenericDINode *N,
1593                                              SmallVectorImpl<uint64_t> &Record,
1594                                              unsigned &Abbrev) {
1595   if (!Abbrev)
1596     Abbrev = createGenericDINodeAbbrev();
1597 
1598   Record.push_back(N->isDistinct());
1599   Record.push_back(N->getTag());
1600   Record.push_back(0); // Per-tag version field; unused for now.
1601 
1602   for (auto &I : N->operands())
1603     Record.push_back(VE.getMetadataOrNullID(I));
1604 
1605   Stream.EmitRecord(bitc::METADATA_GENERIC_DEBUG, Record, Abbrev);
1606   Record.clear();
1607 }
1608 
1609 void ModuleBitcodeWriter::writeDISubrange(const DISubrange *N,
1610                                           SmallVectorImpl<uint64_t> &Record,
1611                                           unsigned Abbrev) {
1612   const uint64_t Version = 2 << 1;
1613   Record.push_back((uint64_t)N->isDistinct() | Version);
1614   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1615   Record.push_back(VE.getMetadataOrNullID(N->getRawLowerBound()));
1616   Record.push_back(VE.getMetadataOrNullID(N->getRawUpperBound()));
1617   Record.push_back(VE.getMetadataOrNullID(N->getRawStride()));
1618 
1619   Stream.EmitRecord(bitc::METADATA_SUBRANGE, Record, Abbrev);
1620   Record.clear();
1621 }
1622 
1623 void ModuleBitcodeWriter::writeDIGenericSubrange(
1624     const DIGenericSubrange *N, SmallVectorImpl<uint64_t> &Record,
1625     unsigned Abbrev) {
1626   Record.push_back((uint64_t)N->isDistinct());
1627   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1628   Record.push_back(VE.getMetadataOrNullID(N->getRawLowerBound()));
1629   Record.push_back(VE.getMetadataOrNullID(N->getRawUpperBound()));
1630   Record.push_back(VE.getMetadataOrNullID(N->getRawStride()));
1631 
1632   Stream.EmitRecord(bitc::METADATA_GENERIC_SUBRANGE, Record, Abbrev);
1633   Record.clear();
1634 }
1635 
1636 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
1637   if ((int64_t)V >= 0)
1638     Vals.push_back(V << 1);
1639   else
1640     Vals.push_back((-V << 1) | 1);
1641 }
1642 
1643 static void emitWideAPInt(SmallVectorImpl<uint64_t> &Vals, const APInt &A) {
1644   // We have an arbitrary precision integer value to write whose
1645   // bit width is > 64. However, in canonical unsigned integer
1646   // format it is likely that the high bits are going to be zero.
1647   // So, we only write the number of active words.
1648   unsigned NumWords = A.getActiveWords();
1649   const uint64_t *RawData = A.getRawData();
1650   for (unsigned i = 0; i < NumWords; i++)
1651     emitSignedInt64(Vals, RawData[i]);
1652 }
1653 
1654 void ModuleBitcodeWriter::writeDIEnumerator(const DIEnumerator *N,
1655                                             SmallVectorImpl<uint64_t> &Record,
1656                                             unsigned Abbrev) {
1657   const uint64_t IsBigInt = 1 << 2;
1658   Record.push_back(IsBigInt | (N->isUnsigned() << 1) | N->isDistinct());
1659   Record.push_back(N->getValue().getBitWidth());
1660   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1661   emitWideAPInt(Record, N->getValue());
1662 
1663   Stream.EmitRecord(bitc::METADATA_ENUMERATOR, Record, Abbrev);
1664   Record.clear();
1665 }
1666 
1667 void ModuleBitcodeWriter::writeDIBasicType(const DIBasicType *N,
1668                                            SmallVectorImpl<uint64_t> &Record,
1669                                            unsigned Abbrev) {
1670   Record.push_back(N->isDistinct());
1671   Record.push_back(N->getTag());
1672   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1673   Record.push_back(N->getSizeInBits());
1674   Record.push_back(N->getAlignInBits());
1675   Record.push_back(N->getEncoding());
1676   Record.push_back(N->getFlags());
1677 
1678   Stream.EmitRecord(bitc::METADATA_BASIC_TYPE, Record, Abbrev);
1679   Record.clear();
1680 }
1681 
1682 void ModuleBitcodeWriter::writeDIStringType(const DIStringType *N,
1683                                             SmallVectorImpl<uint64_t> &Record,
1684                                             unsigned Abbrev) {
1685   Record.push_back(N->isDistinct());
1686   Record.push_back(N->getTag());
1687   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1688   Record.push_back(VE.getMetadataOrNullID(N->getStringLength()));
1689   Record.push_back(VE.getMetadataOrNullID(N->getStringLengthExp()));
1690   Record.push_back(VE.getMetadataOrNullID(N->getStringLocationExp()));
1691   Record.push_back(N->getSizeInBits());
1692   Record.push_back(N->getAlignInBits());
1693   Record.push_back(N->getEncoding());
1694 
1695   Stream.EmitRecord(bitc::METADATA_STRING_TYPE, Record, Abbrev);
1696   Record.clear();
1697 }
1698 
1699 void ModuleBitcodeWriter::writeDIDerivedType(const DIDerivedType *N,
1700                                              SmallVectorImpl<uint64_t> &Record,
1701                                              unsigned Abbrev) {
1702   Record.push_back(N->isDistinct());
1703   Record.push_back(N->getTag());
1704   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1705   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1706   Record.push_back(N->getLine());
1707   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1708   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1709   Record.push_back(N->getSizeInBits());
1710   Record.push_back(N->getAlignInBits());
1711   Record.push_back(N->getOffsetInBits());
1712   Record.push_back(N->getFlags());
1713   Record.push_back(VE.getMetadataOrNullID(N->getExtraData()));
1714 
1715   // DWARF address space is encoded as N->getDWARFAddressSpace() + 1. 0 means
1716   // that there is no DWARF address space associated with DIDerivedType.
1717   if (const auto &DWARFAddressSpace = N->getDWARFAddressSpace())
1718     Record.push_back(*DWARFAddressSpace + 1);
1719   else
1720     Record.push_back(0);
1721 
1722   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1723 
1724   Stream.EmitRecord(bitc::METADATA_DERIVED_TYPE, Record, Abbrev);
1725   Record.clear();
1726 }
1727 
1728 void ModuleBitcodeWriter::writeDICompositeType(
1729     const DICompositeType *N, SmallVectorImpl<uint64_t> &Record,
1730     unsigned Abbrev) {
1731   const unsigned IsNotUsedInOldTypeRef = 0x2;
1732   Record.push_back(IsNotUsedInOldTypeRef | (unsigned)N->isDistinct());
1733   Record.push_back(N->getTag());
1734   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1735   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1736   Record.push_back(N->getLine());
1737   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1738   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1739   Record.push_back(N->getSizeInBits());
1740   Record.push_back(N->getAlignInBits());
1741   Record.push_back(N->getOffsetInBits());
1742   Record.push_back(N->getFlags());
1743   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1744   Record.push_back(N->getRuntimeLang());
1745   Record.push_back(VE.getMetadataOrNullID(N->getVTableHolder()));
1746   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1747   Record.push_back(VE.getMetadataOrNullID(N->getRawIdentifier()));
1748   Record.push_back(VE.getMetadataOrNullID(N->getDiscriminator()));
1749   Record.push_back(VE.getMetadataOrNullID(N->getRawDataLocation()));
1750   Record.push_back(VE.getMetadataOrNullID(N->getRawAssociated()));
1751   Record.push_back(VE.getMetadataOrNullID(N->getRawAllocated()));
1752   Record.push_back(VE.getMetadataOrNullID(N->getRawRank()));
1753   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1754 
1755   Stream.EmitRecord(bitc::METADATA_COMPOSITE_TYPE, Record, Abbrev);
1756   Record.clear();
1757 }
1758 
1759 void ModuleBitcodeWriter::writeDISubroutineType(
1760     const DISubroutineType *N, SmallVectorImpl<uint64_t> &Record,
1761     unsigned Abbrev) {
1762   const unsigned HasNoOldTypeRefs = 0x2;
1763   Record.push_back(HasNoOldTypeRefs | (unsigned)N->isDistinct());
1764   Record.push_back(N->getFlags());
1765   Record.push_back(VE.getMetadataOrNullID(N->getTypeArray().get()));
1766   Record.push_back(N->getCC());
1767 
1768   Stream.EmitRecord(bitc::METADATA_SUBROUTINE_TYPE, Record, Abbrev);
1769   Record.clear();
1770 }
1771 
1772 void ModuleBitcodeWriter::writeDIFile(const DIFile *N,
1773                                       SmallVectorImpl<uint64_t> &Record,
1774                                       unsigned Abbrev) {
1775   Record.push_back(N->isDistinct());
1776   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
1777   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
1778   if (N->getRawChecksum()) {
1779     Record.push_back(N->getRawChecksum()->Kind);
1780     Record.push_back(VE.getMetadataOrNullID(N->getRawChecksum()->Value));
1781   } else {
1782     // Maintain backwards compatibility with the old internal representation of
1783     // CSK_None in ChecksumKind by writing nulls here when Checksum is None.
1784     Record.push_back(0);
1785     Record.push_back(VE.getMetadataOrNullID(nullptr));
1786   }
1787   auto Source = N->getRawSource();
1788   if (Source)
1789     Record.push_back(VE.getMetadataOrNullID(*Source));
1790 
1791   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
1792   Record.clear();
1793 }
1794 
1795 void ModuleBitcodeWriter::writeDICompileUnit(const DICompileUnit *N,
1796                                              SmallVectorImpl<uint64_t> &Record,
1797                                              unsigned Abbrev) {
1798   assert(N->isDistinct() && "Expected distinct compile units");
1799   Record.push_back(/* IsDistinct */ true);
1800   Record.push_back(N->getSourceLanguage());
1801   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1802   Record.push_back(VE.getMetadataOrNullID(N->getRawProducer()));
1803   Record.push_back(N->isOptimized());
1804   Record.push_back(VE.getMetadataOrNullID(N->getRawFlags()));
1805   Record.push_back(N->getRuntimeVersion());
1806   Record.push_back(VE.getMetadataOrNullID(N->getRawSplitDebugFilename()));
1807   Record.push_back(N->getEmissionKind());
1808   Record.push_back(VE.getMetadataOrNullID(N->getEnumTypes().get()));
1809   Record.push_back(VE.getMetadataOrNullID(N->getRetainedTypes().get()));
1810   Record.push_back(/* subprograms */ 0);
1811   Record.push_back(VE.getMetadataOrNullID(N->getGlobalVariables().get()));
1812   Record.push_back(VE.getMetadataOrNullID(N->getImportedEntities().get()));
1813   Record.push_back(N->getDWOId());
1814   Record.push_back(VE.getMetadataOrNullID(N->getMacros().get()));
1815   Record.push_back(N->getSplitDebugInlining());
1816   Record.push_back(N->getDebugInfoForProfiling());
1817   Record.push_back((unsigned)N->getNameTableKind());
1818   Record.push_back(N->getRangesBaseAddress());
1819   Record.push_back(VE.getMetadataOrNullID(N->getRawSysRoot()));
1820   Record.push_back(VE.getMetadataOrNullID(N->getRawSDK()));
1821 
1822   Stream.EmitRecord(bitc::METADATA_COMPILE_UNIT, Record, Abbrev);
1823   Record.clear();
1824 }
1825 
1826 void ModuleBitcodeWriter::writeDISubprogram(const DISubprogram *N,
1827                                             SmallVectorImpl<uint64_t> &Record,
1828                                             unsigned Abbrev) {
1829   const uint64_t HasUnitFlag = 1 << 1;
1830   const uint64_t HasSPFlagsFlag = 1 << 2;
1831   Record.push_back(uint64_t(N->isDistinct()) | HasUnitFlag | HasSPFlagsFlag);
1832   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1833   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1834   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1835   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1836   Record.push_back(N->getLine());
1837   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1838   Record.push_back(N->getScopeLine());
1839   Record.push_back(VE.getMetadataOrNullID(N->getContainingType()));
1840   Record.push_back(N->getSPFlags());
1841   Record.push_back(N->getVirtualIndex());
1842   Record.push_back(N->getFlags());
1843   Record.push_back(VE.getMetadataOrNullID(N->getRawUnit()));
1844   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1845   Record.push_back(VE.getMetadataOrNullID(N->getDeclaration()));
1846   Record.push_back(VE.getMetadataOrNullID(N->getRetainedNodes().get()));
1847   Record.push_back(N->getThisAdjustment());
1848   Record.push_back(VE.getMetadataOrNullID(N->getThrownTypes().get()));
1849   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1850   Record.push_back(VE.getMetadataOrNullID(N->getRawTargetFuncName()));
1851 
1852   Stream.EmitRecord(bitc::METADATA_SUBPROGRAM, Record, Abbrev);
1853   Record.clear();
1854 }
1855 
1856 void ModuleBitcodeWriter::writeDILexicalBlock(const DILexicalBlock *N,
1857                                               SmallVectorImpl<uint64_t> &Record,
1858                                               unsigned Abbrev) {
1859   Record.push_back(N->isDistinct());
1860   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1861   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1862   Record.push_back(N->getLine());
1863   Record.push_back(N->getColumn());
1864 
1865   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK, Record, Abbrev);
1866   Record.clear();
1867 }
1868 
1869 void ModuleBitcodeWriter::writeDILexicalBlockFile(
1870     const DILexicalBlockFile *N, SmallVectorImpl<uint64_t> &Record,
1871     unsigned Abbrev) {
1872   Record.push_back(N->isDistinct());
1873   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1874   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1875   Record.push_back(N->getDiscriminator());
1876 
1877   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK_FILE, Record, Abbrev);
1878   Record.clear();
1879 }
1880 
1881 void ModuleBitcodeWriter::writeDICommonBlock(const DICommonBlock *N,
1882                                              SmallVectorImpl<uint64_t> &Record,
1883                                              unsigned Abbrev) {
1884   Record.push_back(N->isDistinct());
1885   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1886   Record.push_back(VE.getMetadataOrNullID(N->getDecl()));
1887   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1888   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1889   Record.push_back(N->getLineNo());
1890 
1891   Stream.EmitRecord(bitc::METADATA_COMMON_BLOCK, Record, Abbrev);
1892   Record.clear();
1893 }
1894 
1895 void ModuleBitcodeWriter::writeDINamespace(const DINamespace *N,
1896                                            SmallVectorImpl<uint64_t> &Record,
1897                                            unsigned Abbrev) {
1898   Record.push_back(N->isDistinct() | N->getExportSymbols() << 1);
1899   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1900   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1901 
1902   Stream.EmitRecord(bitc::METADATA_NAMESPACE, Record, Abbrev);
1903   Record.clear();
1904 }
1905 
1906 void ModuleBitcodeWriter::writeDIMacro(const DIMacro *N,
1907                                        SmallVectorImpl<uint64_t> &Record,
1908                                        unsigned Abbrev) {
1909   Record.push_back(N->isDistinct());
1910   Record.push_back(N->getMacinfoType());
1911   Record.push_back(N->getLine());
1912   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1913   Record.push_back(VE.getMetadataOrNullID(N->getRawValue()));
1914 
1915   Stream.EmitRecord(bitc::METADATA_MACRO, Record, Abbrev);
1916   Record.clear();
1917 }
1918 
1919 void ModuleBitcodeWriter::writeDIMacroFile(const DIMacroFile *N,
1920                                            SmallVectorImpl<uint64_t> &Record,
1921                                            unsigned Abbrev) {
1922   Record.push_back(N->isDistinct());
1923   Record.push_back(N->getMacinfoType());
1924   Record.push_back(N->getLine());
1925   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1926   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1927 
1928   Stream.EmitRecord(bitc::METADATA_MACRO_FILE, Record, Abbrev);
1929   Record.clear();
1930 }
1931 
1932 void ModuleBitcodeWriter::writeDIArgList(const DIArgList *N,
1933                                          SmallVectorImpl<uint64_t> &Record,
1934                                          unsigned Abbrev) {
1935   Record.reserve(N->getArgs().size());
1936   for (ValueAsMetadata *MD : N->getArgs())
1937     Record.push_back(VE.getMetadataID(MD));
1938 
1939   Stream.EmitRecord(bitc::METADATA_ARG_LIST, Record, Abbrev);
1940   Record.clear();
1941 }
1942 
1943 void ModuleBitcodeWriter::writeDIModule(const DIModule *N,
1944                                         SmallVectorImpl<uint64_t> &Record,
1945                                         unsigned Abbrev) {
1946   Record.push_back(N->isDistinct());
1947   for (auto &I : N->operands())
1948     Record.push_back(VE.getMetadataOrNullID(I));
1949   Record.push_back(N->getLineNo());
1950   Record.push_back(N->getIsDecl());
1951 
1952   Stream.EmitRecord(bitc::METADATA_MODULE, Record, Abbrev);
1953   Record.clear();
1954 }
1955 
1956 void ModuleBitcodeWriter::writeDITemplateTypeParameter(
1957     const DITemplateTypeParameter *N, SmallVectorImpl<uint64_t> &Record,
1958     unsigned Abbrev) {
1959   Record.push_back(N->isDistinct());
1960   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1961   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1962   Record.push_back(N->isDefault());
1963 
1964   Stream.EmitRecord(bitc::METADATA_TEMPLATE_TYPE, Record, Abbrev);
1965   Record.clear();
1966 }
1967 
1968 void ModuleBitcodeWriter::writeDITemplateValueParameter(
1969     const DITemplateValueParameter *N, SmallVectorImpl<uint64_t> &Record,
1970     unsigned Abbrev) {
1971   Record.push_back(N->isDistinct());
1972   Record.push_back(N->getTag());
1973   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1974   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1975   Record.push_back(N->isDefault());
1976   Record.push_back(VE.getMetadataOrNullID(N->getValue()));
1977 
1978   Stream.EmitRecord(bitc::METADATA_TEMPLATE_VALUE, Record, Abbrev);
1979   Record.clear();
1980 }
1981 
1982 void ModuleBitcodeWriter::writeDIGlobalVariable(
1983     const DIGlobalVariable *N, SmallVectorImpl<uint64_t> &Record,
1984     unsigned Abbrev) {
1985   const uint64_t Version = 2 << 1;
1986   Record.push_back((uint64_t)N->isDistinct() | Version);
1987   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1988   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1989   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1990   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1991   Record.push_back(N->getLine());
1992   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1993   Record.push_back(N->isLocalToUnit());
1994   Record.push_back(N->isDefinition());
1995   Record.push_back(VE.getMetadataOrNullID(N->getStaticDataMemberDeclaration()));
1996   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams()));
1997   Record.push_back(N->getAlignInBits());
1998   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1999 
2000   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR, Record, Abbrev);
2001   Record.clear();
2002 }
2003 
2004 void ModuleBitcodeWriter::writeDILocalVariable(
2005     const DILocalVariable *N, SmallVectorImpl<uint64_t> &Record,
2006     unsigned Abbrev) {
2007   // In order to support all possible bitcode formats in BitcodeReader we need
2008   // to distinguish the following cases:
2009   // 1) Record has no artificial tag (Record[1]),
2010   //   has no obsolete inlinedAt field (Record[9]).
2011   //   In this case Record size will be 8, HasAlignment flag is false.
2012   // 2) Record has artificial tag (Record[1]),
2013   //   has no obsolete inlignedAt field (Record[9]).
2014   //   In this case Record size will be 9, HasAlignment flag is false.
2015   // 3) Record has both artificial tag (Record[1]) and
2016   //   obsolete inlignedAt field (Record[9]).
2017   //   In this case Record size will be 10, HasAlignment flag is false.
2018   // 4) Record has neither artificial tag, nor inlignedAt field, but
2019   //   HasAlignment flag is true and Record[8] contains alignment value.
2020   const uint64_t HasAlignmentFlag = 1 << 1;
2021   Record.push_back((uint64_t)N->isDistinct() | HasAlignmentFlag);
2022   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2023   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2024   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2025   Record.push_back(N->getLine());
2026   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2027   Record.push_back(N->getArg());
2028   Record.push_back(N->getFlags());
2029   Record.push_back(N->getAlignInBits());
2030   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
2031 
2032   Stream.EmitRecord(bitc::METADATA_LOCAL_VAR, Record, Abbrev);
2033   Record.clear();
2034 }
2035 
2036 void ModuleBitcodeWriter::writeDILabel(
2037     const DILabel *N, SmallVectorImpl<uint64_t> &Record,
2038     unsigned Abbrev) {
2039   Record.push_back((uint64_t)N->isDistinct());
2040   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2041   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2042   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2043   Record.push_back(N->getLine());
2044 
2045   Stream.EmitRecord(bitc::METADATA_LABEL, Record, Abbrev);
2046   Record.clear();
2047 }
2048 
2049 void ModuleBitcodeWriter::writeDIExpression(const DIExpression *N,
2050                                             SmallVectorImpl<uint64_t> &Record,
2051                                             unsigned Abbrev) {
2052   Record.reserve(N->getElements().size() + 1);
2053   const uint64_t Version = 3 << 1;
2054   Record.push_back((uint64_t)N->isDistinct() | Version);
2055   Record.append(N->elements_begin(), N->elements_end());
2056 
2057   Stream.EmitRecord(bitc::METADATA_EXPRESSION, Record, Abbrev);
2058   Record.clear();
2059 }
2060 
2061 void ModuleBitcodeWriter::writeDIGlobalVariableExpression(
2062     const DIGlobalVariableExpression *N, SmallVectorImpl<uint64_t> &Record,
2063     unsigned Abbrev) {
2064   Record.push_back(N->isDistinct());
2065   Record.push_back(VE.getMetadataOrNullID(N->getVariable()));
2066   Record.push_back(VE.getMetadataOrNullID(N->getExpression()));
2067 
2068   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR_EXPR, Record, Abbrev);
2069   Record.clear();
2070 }
2071 
2072 void ModuleBitcodeWriter::writeDIObjCProperty(const DIObjCProperty *N,
2073                                               SmallVectorImpl<uint64_t> &Record,
2074                                               unsigned Abbrev) {
2075   Record.push_back(N->isDistinct());
2076   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2077   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2078   Record.push_back(N->getLine());
2079   Record.push_back(VE.getMetadataOrNullID(N->getRawSetterName()));
2080   Record.push_back(VE.getMetadataOrNullID(N->getRawGetterName()));
2081   Record.push_back(N->getAttributes());
2082   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2083 
2084   Stream.EmitRecord(bitc::METADATA_OBJC_PROPERTY, Record, Abbrev);
2085   Record.clear();
2086 }
2087 
2088 void ModuleBitcodeWriter::writeDIImportedEntity(
2089     const DIImportedEntity *N, SmallVectorImpl<uint64_t> &Record,
2090     unsigned Abbrev) {
2091   Record.push_back(N->isDistinct());
2092   Record.push_back(N->getTag());
2093   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2094   Record.push_back(VE.getMetadataOrNullID(N->getEntity()));
2095   Record.push_back(N->getLine());
2096   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2097   Record.push_back(VE.getMetadataOrNullID(N->getRawFile()));
2098   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
2099 
2100   Stream.EmitRecord(bitc::METADATA_IMPORTED_ENTITY, Record, Abbrev);
2101   Record.clear();
2102 }
2103 
2104 unsigned ModuleBitcodeWriter::createNamedMetadataAbbrev() {
2105   auto Abbv = std::make_shared<BitCodeAbbrev>();
2106   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
2107   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2108   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2109   return Stream.EmitAbbrev(std::move(Abbv));
2110 }
2111 
2112 void ModuleBitcodeWriter::writeNamedMetadata(
2113     SmallVectorImpl<uint64_t> &Record) {
2114   if (M.named_metadata_empty())
2115     return;
2116 
2117   unsigned Abbrev = createNamedMetadataAbbrev();
2118   for (const NamedMDNode &NMD : M.named_metadata()) {
2119     // Write name.
2120     StringRef Str = NMD.getName();
2121     Record.append(Str.bytes_begin(), Str.bytes_end());
2122     Stream.EmitRecord(bitc::METADATA_NAME, Record, Abbrev);
2123     Record.clear();
2124 
2125     // Write named metadata operands.
2126     for (const MDNode *N : NMD.operands())
2127       Record.push_back(VE.getMetadataID(N));
2128     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
2129     Record.clear();
2130   }
2131 }
2132 
2133 unsigned ModuleBitcodeWriter::createMetadataStringsAbbrev() {
2134   auto Abbv = std::make_shared<BitCodeAbbrev>();
2135   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRINGS));
2136   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // # of strings
2137   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // offset to chars
2138   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
2139   return Stream.EmitAbbrev(std::move(Abbv));
2140 }
2141 
2142 /// Write out a record for MDString.
2143 ///
2144 /// All the metadata strings in a metadata block are emitted in a single
2145 /// record.  The sizes and strings themselves are shoved into a blob.
2146 void ModuleBitcodeWriter::writeMetadataStrings(
2147     ArrayRef<const Metadata *> Strings, SmallVectorImpl<uint64_t> &Record) {
2148   if (Strings.empty())
2149     return;
2150 
2151   // Start the record with the number of strings.
2152   Record.push_back(bitc::METADATA_STRINGS);
2153   Record.push_back(Strings.size());
2154 
2155   // Emit the sizes of the strings in the blob.
2156   SmallString<256> Blob;
2157   {
2158     BitstreamWriter W(Blob);
2159     for (const Metadata *MD : Strings)
2160       W.EmitVBR(cast<MDString>(MD)->getLength(), 6);
2161     W.FlushToWord();
2162   }
2163 
2164   // Add the offset to the strings to the record.
2165   Record.push_back(Blob.size());
2166 
2167   // Add the strings to the blob.
2168   for (const Metadata *MD : Strings)
2169     Blob.append(cast<MDString>(MD)->getString());
2170 
2171   // Emit the final record.
2172   Stream.EmitRecordWithBlob(createMetadataStringsAbbrev(), Record, Blob);
2173   Record.clear();
2174 }
2175 
2176 // Generates an enum to use as an index in the Abbrev array of Metadata record.
2177 enum MetadataAbbrev : unsigned {
2178 #define HANDLE_MDNODE_LEAF(CLASS) CLASS##AbbrevID,
2179 #include "llvm/IR/Metadata.def"
2180   LastPlusOne
2181 };
2182 
2183 void ModuleBitcodeWriter::writeMetadataRecords(
2184     ArrayRef<const Metadata *> MDs, SmallVectorImpl<uint64_t> &Record,
2185     std::vector<unsigned> *MDAbbrevs, std::vector<uint64_t> *IndexPos) {
2186   if (MDs.empty())
2187     return;
2188 
2189   // Initialize MDNode abbreviations.
2190 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
2191 #include "llvm/IR/Metadata.def"
2192 
2193   for (const Metadata *MD : MDs) {
2194     if (IndexPos)
2195       IndexPos->push_back(Stream.GetCurrentBitNo());
2196     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
2197       assert(N->isResolved() && "Expected forward references to be resolved");
2198 
2199       switch (N->getMetadataID()) {
2200       default:
2201         llvm_unreachable("Invalid MDNode subclass");
2202 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
2203   case Metadata::CLASS##Kind:                                                  \
2204     if (MDAbbrevs)                                                             \
2205       write##CLASS(cast<CLASS>(N), Record,                                     \
2206                    (*MDAbbrevs)[MetadataAbbrev::CLASS##AbbrevID]);             \
2207     else                                                                       \
2208       write##CLASS(cast<CLASS>(N), Record, CLASS##Abbrev);                     \
2209     continue;
2210 #include "llvm/IR/Metadata.def"
2211       }
2212     }
2213     writeValueAsMetadata(cast<ValueAsMetadata>(MD), Record);
2214   }
2215 }
2216 
2217 void ModuleBitcodeWriter::writeModuleMetadata() {
2218   if (!VE.hasMDs() && M.named_metadata_empty())
2219     return;
2220 
2221   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 4);
2222   SmallVector<uint64_t, 64> Record;
2223 
2224   // Emit all abbrevs upfront, so that the reader can jump in the middle of the
2225   // block and load any metadata.
2226   std::vector<unsigned> MDAbbrevs;
2227 
2228   MDAbbrevs.resize(MetadataAbbrev::LastPlusOne);
2229   MDAbbrevs[MetadataAbbrev::DILocationAbbrevID] = createDILocationAbbrev();
2230   MDAbbrevs[MetadataAbbrev::GenericDINodeAbbrevID] =
2231       createGenericDINodeAbbrev();
2232 
2233   auto Abbv = std::make_shared<BitCodeAbbrev>();
2234   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX_OFFSET));
2235   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2236   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2237   unsigned OffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2238 
2239   Abbv = std::make_shared<BitCodeAbbrev>();
2240   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX));
2241   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2242   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2243   unsigned IndexAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2244 
2245   // Emit MDStrings together upfront.
2246   writeMetadataStrings(VE.getMDStrings(), Record);
2247 
2248   // We only emit an index for the metadata record if we have more than a given
2249   // (naive) threshold of metadatas, otherwise it is not worth it.
2250   if (VE.getNonMDStrings().size() > IndexThreshold) {
2251     // Write a placeholder value in for the offset of the metadata index,
2252     // which is written after the records, so that it can include
2253     // the offset of each entry. The placeholder offset will be
2254     // updated after all records are emitted.
2255     uint64_t Vals[] = {0, 0};
2256     Stream.EmitRecord(bitc::METADATA_INDEX_OFFSET, Vals, OffsetAbbrev);
2257   }
2258 
2259   // Compute and save the bit offset to the current position, which will be
2260   // patched when we emit the index later. We can simply subtract the 64-bit
2261   // fixed size from the current bit number to get the location to backpatch.
2262   uint64_t IndexOffsetRecordBitPos = Stream.GetCurrentBitNo();
2263 
2264   // This index will contain the bitpos for each individual record.
2265   std::vector<uint64_t> IndexPos;
2266   IndexPos.reserve(VE.getNonMDStrings().size());
2267 
2268   // Write all the records
2269   writeMetadataRecords(VE.getNonMDStrings(), Record, &MDAbbrevs, &IndexPos);
2270 
2271   if (VE.getNonMDStrings().size() > IndexThreshold) {
2272     // Now that we have emitted all the records we will emit the index. But
2273     // first
2274     // backpatch the forward reference so that the reader can skip the records
2275     // efficiently.
2276     Stream.BackpatchWord64(IndexOffsetRecordBitPos - 64,
2277                            Stream.GetCurrentBitNo() - IndexOffsetRecordBitPos);
2278 
2279     // Delta encode the index.
2280     uint64_t PreviousValue = IndexOffsetRecordBitPos;
2281     for (auto &Elt : IndexPos) {
2282       auto EltDelta = Elt - PreviousValue;
2283       PreviousValue = Elt;
2284       Elt = EltDelta;
2285     }
2286     // Emit the index record.
2287     Stream.EmitRecord(bitc::METADATA_INDEX, IndexPos, IndexAbbrev);
2288     IndexPos.clear();
2289   }
2290 
2291   // Write the named metadata now.
2292   writeNamedMetadata(Record);
2293 
2294   auto AddDeclAttachedMetadata = [&](const GlobalObject &GO) {
2295     SmallVector<uint64_t, 4> Record;
2296     Record.push_back(VE.getValueID(&GO));
2297     pushGlobalMetadataAttachment(Record, GO);
2298     Stream.EmitRecord(bitc::METADATA_GLOBAL_DECL_ATTACHMENT, Record);
2299   };
2300   for (const Function &F : M)
2301     if (F.isDeclaration() && F.hasMetadata())
2302       AddDeclAttachedMetadata(F);
2303   // FIXME: Only store metadata for declarations here, and move data for global
2304   // variable definitions to a separate block (PR28134).
2305   for (const GlobalVariable &GV : M.globals())
2306     if (GV.hasMetadata())
2307       AddDeclAttachedMetadata(GV);
2308 
2309   Stream.ExitBlock();
2310 }
2311 
2312 void ModuleBitcodeWriter::writeFunctionMetadata(const Function &F) {
2313   if (!VE.hasMDs())
2314     return;
2315 
2316   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
2317   SmallVector<uint64_t, 64> Record;
2318   writeMetadataStrings(VE.getMDStrings(), Record);
2319   writeMetadataRecords(VE.getNonMDStrings(), Record);
2320   Stream.ExitBlock();
2321 }
2322 
2323 void ModuleBitcodeWriter::pushGlobalMetadataAttachment(
2324     SmallVectorImpl<uint64_t> &Record, const GlobalObject &GO) {
2325   // [n x [id, mdnode]]
2326   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2327   GO.getAllMetadata(MDs);
2328   for (const auto &I : MDs) {
2329     Record.push_back(I.first);
2330     Record.push_back(VE.getMetadataID(I.second));
2331   }
2332 }
2333 
2334 void ModuleBitcodeWriter::writeFunctionMetadataAttachment(const Function &F) {
2335   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
2336 
2337   SmallVector<uint64_t, 64> Record;
2338 
2339   if (F.hasMetadata()) {
2340     pushGlobalMetadataAttachment(Record, F);
2341     Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2342     Record.clear();
2343   }
2344 
2345   // Write metadata attachments
2346   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
2347   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2348   for (const BasicBlock &BB : F)
2349     for (const Instruction &I : BB) {
2350       MDs.clear();
2351       I.getAllMetadataOtherThanDebugLoc(MDs);
2352 
2353       // If no metadata, ignore instruction.
2354       if (MDs.empty()) continue;
2355 
2356       Record.push_back(VE.getInstructionID(&I));
2357 
2358       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
2359         Record.push_back(MDs[i].first);
2360         Record.push_back(VE.getMetadataID(MDs[i].second));
2361       }
2362       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2363       Record.clear();
2364     }
2365 
2366   Stream.ExitBlock();
2367 }
2368 
2369 void ModuleBitcodeWriter::writeModuleMetadataKinds() {
2370   SmallVector<uint64_t, 64> Record;
2371 
2372   // Write metadata kinds
2373   // METADATA_KIND - [n x [id, name]]
2374   SmallVector<StringRef, 8> Names;
2375   M.getMDKindNames(Names);
2376 
2377   if (Names.empty()) return;
2378 
2379   Stream.EnterSubblock(bitc::METADATA_KIND_BLOCK_ID, 3);
2380 
2381   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
2382     Record.push_back(MDKindID);
2383     StringRef KName = Names[MDKindID];
2384     Record.append(KName.begin(), KName.end());
2385 
2386     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
2387     Record.clear();
2388   }
2389 
2390   Stream.ExitBlock();
2391 }
2392 
2393 void ModuleBitcodeWriter::writeOperandBundleTags() {
2394   // Write metadata kinds
2395   //
2396   // OPERAND_BUNDLE_TAGS_BLOCK_ID : N x OPERAND_BUNDLE_TAG
2397   //
2398   // OPERAND_BUNDLE_TAG - [strchr x N]
2399 
2400   SmallVector<StringRef, 8> Tags;
2401   M.getOperandBundleTags(Tags);
2402 
2403   if (Tags.empty())
2404     return;
2405 
2406   Stream.EnterSubblock(bitc::OPERAND_BUNDLE_TAGS_BLOCK_ID, 3);
2407 
2408   SmallVector<uint64_t, 64> Record;
2409 
2410   for (auto Tag : Tags) {
2411     Record.append(Tag.begin(), Tag.end());
2412 
2413     Stream.EmitRecord(bitc::OPERAND_BUNDLE_TAG, Record, 0);
2414     Record.clear();
2415   }
2416 
2417   Stream.ExitBlock();
2418 }
2419 
2420 void ModuleBitcodeWriter::writeSyncScopeNames() {
2421   SmallVector<StringRef, 8> SSNs;
2422   M.getContext().getSyncScopeNames(SSNs);
2423   if (SSNs.empty())
2424     return;
2425 
2426   Stream.EnterSubblock(bitc::SYNC_SCOPE_NAMES_BLOCK_ID, 2);
2427 
2428   SmallVector<uint64_t, 64> Record;
2429   for (auto SSN : SSNs) {
2430     Record.append(SSN.begin(), SSN.end());
2431     Stream.EmitRecord(bitc::SYNC_SCOPE_NAME, Record, 0);
2432     Record.clear();
2433   }
2434 
2435   Stream.ExitBlock();
2436 }
2437 
2438 void ModuleBitcodeWriter::writeConstants(unsigned FirstVal, unsigned LastVal,
2439                                          bool isGlobal) {
2440   if (FirstVal == LastVal) return;
2441 
2442   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
2443 
2444   unsigned AggregateAbbrev = 0;
2445   unsigned String8Abbrev = 0;
2446   unsigned CString7Abbrev = 0;
2447   unsigned CString6Abbrev = 0;
2448   // If this is a constant pool for the module, emit module-specific abbrevs.
2449   if (isGlobal) {
2450     // Abbrev for CST_CODE_AGGREGATE.
2451     auto Abbv = std::make_shared<BitCodeAbbrev>();
2452     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
2453     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2454     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
2455     AggregateAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2456 
2457     // Abbrev for CST_CODE_STRING.
2458     Abbv = std::make_shared<BitCodeAbbrev>();
2459     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
2460     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2461     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2462     String8Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2463     // Abbrev for CST_CODE_CSTRING.
2464     Abbv = std::make_shared<BitCodeAbbrev>();
2465     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2466     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2467     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2468     CString7Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2469     // Abbrev for CST_CODE_CSTRING.
2470     Abbv = std::make_shared<BitCodeAbbrev>();
2471     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2472     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2473     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2474     CString6Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2475   }
2476 
2477   SmallVector<uint64_t, 64> Record;
2478 
2479   const ValueEnumerator::ValueList &Vals = VE.getValues();
2480   Type *LastTy = nullptr;
2481   for (unsigned i = FirstVal; i != LastVal; ++i) {
2482     const Value *V = Vals[i].first;
2483     // If we need to switch types, do so now.
2484     if (V->getType() != LastTy) {
2485       LastTy = V->getType();
2486       Record.push_back(VE.getTypeID(LastTy));
2487       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
2488                         CONSTANTS_SETTYPE_ABBREV);
2489       Record.clear();
2490     }
2491 
2492     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
2493       Record.push_back(VE.getTypeID(IA->getFunctionType()));
2494       Record.push_back(
2495           unsigned(IA->hasSideEffects()) | unsigned(IA->isAlignStack()) << 1 |
2496           unsigned(IA->getDialect() & 1) << 2 | unsigned(IA->canThrow()) << 3);
2497 
2498       // Add the asm string.
2499       const std::string &AsmStr = IA->getAsmString();
2500       Record.push_back(AsmStr.size());
2501       Record.append(AsmStr.begin(), AsmStr.end());
2502 
2503       // Add the constraint string.
2504       const std::string &ConstraintStr = IA->getConstraintString();
2505       Record.push_back(ConstraintStr.size());
2506       Record.append(ConstraintStr.begin(), ConstraintStr.end());
2507       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
2508       Record.clear();
2509       continue;
2510     }
2511     const Constant *C = cast<Constant>(V);
2512     unsigned Code = -1U;
2513     unsigned AbbrevToUse = 0;
2514     if (C->isNullValue()) {
2515       Code = bitc::CST_CODE_NULL;
2516     } else if (isa<PoisonValue>(C)) {
2517       Code = bitc::CST_CODE_POISON;
2518     } else if (isa<UndefValue>(C)) {
2519       Code = bitc::CST_CODE_UNDEF;
2520     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
2521       if (IV->getBitWidth() <= 64) {
2522         uint64_t V = IV->getSExtValue();
2523         emitSignedInt64(Record, V);
2524         Code = bitc::CST_CODE_INTEGER;
2525         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
2526       } else {                             // Wide integers, > 64 bits in size.
2527         emitWideAPInt(Record, IV->getValue());
2528         Code = bitc::CST_CODE_WIDE_INTEGER;
2529       }
2530     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
2531       Code = bitc::CST_CODE_FLOAT;
2532       Type *Ty = CFP->getType();
2533       if (Ty->isHalfTy() || Ty->isBFloatTy() || Ty->isFloatTy() ||
2534           Ty->isDoubleTy()) {
2535         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
2536       } else if (Ty->isX86_FP80Ty()) {
2537         // api needed to prevent premature destruction
2538         // bits are not in the same order as a normal i80 APInt, compensate.
2539         APInt api = CFP->getValueAPF().bitcastToAPInt();
2540         const uint64_t *p = api.getRawData();
2541         Record.push_back((p[1] << 48) | (p[0] >> 16));
2542         Record.push_back(p[0] & 0xffffLL);
2543       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
2544         APInt api = CFP->getValueAPF().bitcastToAPInt();
2545         const uint64_t *p = api.getRawData();
2546         Record.push_back(p[0]);
2547         Record.push_back(p[1]);
2548       } else {
2549         assert(0 && "Unknown FP type!");
2550       }
2551     } else if (isa<ConstantDataSequential>(C) &&
2552                cast<ConstantDataSequential>(C)->isString()) {
2553       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
2554       // Emit constant strings specially.
2555       unsigned NumElts = Str->getNumElements();
2556       // If this is a null-terminated string, use the denser CSTRING encoding.
2557       if (Str->isCString()) {
2558         Code = bitc::CST_CODE_CSTRING;
2559         --NumElts;  // Don't encode the null, which isn't allowed by char6.
2560       } else {
2561         Code = bitc::CST_CODE_STRING;
2562         AbbrevToUse = String8Abbrev;
2563       }
2564       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
2565       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
2566       for (unsigned i = 0; i != NumElts; ++i) {
2567         unsigned char V = Str->getElementAsInteger(i);
2568         Record.push_back(V);
2569         isCStr7 &= (V & 128) == 0;
2570         if (isCStrChar6)
2571           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
2572       }
2573 
2574       if (isCStrChar6)
2575         AbbrevToUse = CString6Abbrev;
2576       else if (isCStr7)
2577         AbbrevToUse = CString7Abbrev;
2578     } else if (const ConstantDataSequential *CDS =
2579                   dyn_cast<ConstantDataSequential>(C)) {
2580       Code = bitc::CST_CODE_DATA;
2581       Type *EltTy = CDS->getElementType();
2582       if (isa<IntegerType>(EltTy)) {
2583         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2584           Record.push_back(CDS->getElementAsInteger(i));
2585       } else {
2586         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2587           Record.push_back(
2588               CDS->getElementAsAPFloat(i).bitcastToAPInt().getLimitedValue());
2589       }
2590     } else if (isa<ConstantAggregate>(C)) {
2591       Code = bitc::CST_CODE_AGGREGATE;
2592       for (const Value *Op : C->operands())
2593         Record.push_back(VE.getValueID(Op));
2594       AbbrevToUse = AggregateAbbrev;
2595     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
2596       switch (CE->getOpcode()) {
2597       default:
2598         if (Instruction::isCast(CE->getOpcode())) {
2599           Code = bitc::CST_CODE_CE_CAST;
2600           Record.push_back(getEncodedCastOpcode(CE->getOpcode()));
2601           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2602           Record.push_back(VE.getValueID(C->getOperand(0)));
2603           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
2604         } else {
2605           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
2606           Code = bitc::CST_CODE_CE_BINOP;
2607           Record.push_back(getEncodedBinaryOpcode(CE->getOpcode()));
2608           Record.push_back(VE.getValueID(C->getOperand(0)));
2609           Record.push_back(VE.getValueID(C->getOperand(1)));
2610           uint64_t Flags = getOptimizationFlags(CE);
2611           if (Flags != 0)
2612             Record.push_back(Flags);
2613         }
2614         break;
2615       case Instruction::FNeg: {
2616         assert(CE->getNumOperands() == 1 && "Unknown constant expr!");
2617         Code = bitc::CST_CODE_CE_UNOP;
2618         Record.push_back(getEncodedUnaryOpcode(CE->getOpcode()));
2619         Record.push_back(VE.getValueID(C->getOperand(0)));
2620         uint64_t Flags = getOptimizationFlags(CE);
2621         if (Flags != 0)
2622           Record.push_back(Flags);
2623         break;
2624       }
2625       case Instruction::GetElementPtr: {
2626         Code = bitc::CST_CODE_CE_GEP;
2627         const auto *GO = cast<GEPOperator>(C);
2628         Record.push_back(VE.getTypeID(GO->getSourceElementType()));
2629         if (Optional<unsigned> Idx = GO->getInRangeIndex()) {
2630           Code = bitc::CST_CODE_CE_GEP_WITH_INRANGE_INDEX;
2631           Record.push_back((*Idx << 1) | GO->isInBounds());
2632         } else if (GO->isInBounds())
2633           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
2634         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
2635           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
2636           Record.push_back(VE.getValueID(C->getOperand(i)));
2637         }
2638         break;
2639       }
2640       case Instruction::Select:
2641         Code = bitc::CST_CODE_CE_SELECT;
2642         Record.push_back(VE.getValueID(C->getOperand(0)));
2643         Record.push_back(VE.getValueID(C->getOperand(1)));
2644         Record.push_back(VE.getValueID(C->getOperand(2)));
2645         break;
2646       case Instruction::ExtractElement:
2647         Code = bitc::CST_CODE_CE_EXTRACTELT;
2648         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2649         Record.push_back(VE.getValueID(C->getOperand(0)));
2650         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
2651         Record.push_back(VE.getValueID(C->getOperand(1)));
2652         break;
2653       case Instruction::InsertElement:
2654         Code = bitc::CST_CODE_CE_INSERTELT;
2655         Record.push_back(VE.getValueID(C->getOperand(0)));
2656         Record.push_back(VE.getValueID(C->getOperand(1)));
2657         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
2658         Record.push_back(VE.getValueID(C->getOperand(2)));
2659         break;
2660       case Instruction::ShuffleVector:
2661         // If the return type and argument types are the same, this is a
2662         // standard shufflevector instruction.  If the types are different,
2663         // then the shuffle is widening or truncating the input vectors, and
2664         // the argument type must also be encoded.
2665         if (C->getType() == C->getOperand(0)->getType()) {
2666           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
2667         } else {
2668           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
2669           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2670         }
2671         Record.push_back(VE.getValueID(C->getOperand(0)));
2672         Record.push_back(VE.getValueID(C->getOperand(1)));
2673         Record.push_back(VE.getValueID(CE->getShuffleMaskForBitcode()));
2674         break;
2675       case Instruction::ICmp:
2676       case Instruction::FCmp:
2677         Code = bitc::CST_CODE_CE_CMP;
2678         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2679         Record.push_back(VE.getValueID(C->getOperand(0)));
2680         Record.push_back(VE.getValueID(C->getOperand(1)));
2681         Record.push_back(CE->getPredicate());
2682         break;
2683       }
2684     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
2685       Code = bitc::CST_CODE_BLOCKADDRESS;
2686       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
2687       Record.push_back(VE.getValueID(BA->getFunction()));
2688       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
2689     } else if (const auto *Equiv = dyn_cast<DSOLocalEquivalent>(C)) {
2690       Code = bitc::CST_CODE_DSO_LOCAL_EQUIVALENT;
2691       Record.push_back(VE.getTypeID(Equiv->getGlobalValue()->getType()));
2692       Record.push_back(VE.getValueID(Equiv->getGlobalValue()));
2693     } else if (const auto *NC = dyn_cast<NoCFIValue>(C)) {
2694       Code = bitc::CST_CODE_NO_CFI_VALUE;
2695       Record.push_back(VE.getTypeID(NC->getGlobalValue()->getType()));
2696       Record.push_back(VE.getValueID(NC->getGlobalValue()));
2697     } else {
2698 #ifndef NDEBUG
2699       C->dump();
2700 #endif
2701       llvm_unreachable("Unknown constant!");
2702     }
2703     Stream.EmitRecord(Code, Record, AbbrevToUse);
2704     Record.clear();
2705   }
2706 
2707   Stream.ExitBlock();
2708 }
2709 
2710 void ModuleBitcodeWriter::writeModuleConstants() {
2711   const ValueEnumerator::ValueList &Vals = VE.getValues();
2712 
2713   // Find the first constant to emit, which is the first non-globalvalue value.
2714   // We know globalvalues have been emitted by WriteModuleInfo.
2715   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
2716     if (!isa<GlobalValue>(Vals[i].first)) {
2717       writeConstants(i, Vals.size(), true);
2718       return;
2719     }
2720   }
2721 }
2722 
2723 /// pushValueAndType - The file has to encode both the value and type id for
2724 /// many values, because we need to know what type to create for forward
2725 /// references.  However, most operands are not forward references, so this type
2726 /// field is not needed.
2727 ///
2728 /// This function adds V's value ID to Vals.  If the value ID is higher than the
2729 /// instruction ID, then it is a forward reference, and it also includes the
2730 /// type ID.  The value ID that is written is encoded relative to the InstID.
2731 bool ModuleBitcodeWriter::pushValueAndType(const Value *V, unsigned InstID,
2732                                            SmallVectorImpl<unsigned> &Vals) {
2733   unsigned ValID = VE.getValueID(V);
2734   // Make encoding relative to the InstID.
2735   Vals.push_back(InstID - ValID);
2736   if (ValID >= InstID) {
2737     Vals.push_back(VE.getTypeID(V->getType()));
2738     return true;
2739   }
2740   return false;
2741 }
2742 
2743 void ModuleBitcodeWriter::writeOperandBundles(const CallBase &CS,
2744                                               unsigned InstID) {
2745   SmallVector<unsigned, 64> Record;
2746   LLVMContext &C = CS.getContext();
2747 
2748   for (unsigned i = 0, e = CS.getNumOperandBundles(); i != e; ++i) {
2749     const auto &Bundle = CS.getOperandBundleAt(i);
2750     Record.push_back(C.getOperandBundleTagID(Bundle.getTagName()));
2751 
2752     for (auto &Input : Bundle.Inputs)
2753       pushValueAndType(Input, InstID, Record);
2754 
2755     Stream.EmitRecord(bitc::FUNC_CODE_OPERAND_BUNDLE, Record);
2756     Record.clear();
2757   }
2758 }
2759 
2760 /// pushValue - Like pushValueAndType, but where the type of the value is
2761 /// omitted (perhaps it was already encoded in an earlier operand).
2762 void ModuleBitcodeWriter::pushValue(const Value *V, unsigned InstID,
2763                                     SmallVectorImpl<unsigned> &Vals) {
2764   unsigned ValID = VE.getValueID(V);
2765   Vals.push_back(InstID - ValID);
2766 }
2767 
2768 void ModuleBitcodeWriter::pushValueSigned(const Value *V, unsigned InstID,
2769                                           SmallVectorImpl<uint64_t> &Vals) {
2770   unsigned ValID = VE.getValueID(V);
2771   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
2772   emitSignedInt64(Vals, diff);
2773 }
2774 
2775 /// WriteInstruction - Emit an instruction to the specified stream.
2776 void ModuleBitcodeWriter::writeInstruction(const Instruction &I,
2777                                            unsigned InstID,
2778                                            SmallVectorImpl<unsigned> &Vals) {
2779   unsigned Code = 0;
2780   unsigned AbbrevToUse = 0;
2781   VE.setInstructionID(&I);
2782   switch (I.getOpcode()) {
2783   default:
2784     if (Instruction::isCast(I.getOpcode())) {
2785       Code = bitc::FUNC_CODE_INST_CAST;
2786       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2787         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
2788       Vals.push_back(VE.getTypeID(I.getType()));
2789       Vals.push_back(getEncodedCastOpcode(I.getOpcode()));
2790     } else {
2791       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
2792       Code = bitc::FUNC_CODE_INST_BINOP;
2793       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2794         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
2795       pushValue(I.getOperand(1), InstID, Vals);
2796       Vals.push_back(getEncodedBinaryOpcode(I.getOpcode()));
2797       uint64_t Flags = getOptimizationFlags(&I);
2798       if (Flags != 0) {
2799         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
2800           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
2801         Vals.push_back(Flags);
2802       }
2803     }
2804     break;
2805   case Instruction::FNeg: {
2806     Code = bitc::FUNC_CODE_INST_UNOP;
2807     if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2808       AbbrevToUse = FUNCTION_INST_UNOP_ABBREV;
2809     Vals.push_back(getEncodedUnaryOpcode(I.getOpcode()));
2810     uint64_t Flags = getOptimizationFlags(&I);
2811     if (Flags != 0) {
2812       if (AbbrevToUse == FUNCTION_INST_UNOP_ABBREV)
2813         AbbrevToUse = FUNCTION_INST_UNOP_FLAGS_ABBREV;
2814       Vals.push_back(Flags);
2815     }
2816     break;
2817   }
2818   case Instruction::GetElementPtr: {
2819     Code = bitc::FUNC_CODE_INST_GEP;
2820     AbbrevToUse = FUNCTION_INST_GEP_ABBREV;
2821     auto &GEPInst = cast<GetElementPtrInst>(I);
2822     Vals.push_back(GEPInst.isInBounds());
2823     Vals.push_back(VE.getTypeID(GEPInst.getSourceElementType()));
2824     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
2825       pushValueAndType(I.getOperand(i), InstID, Vals);
2826     break;
2827   }
2828   case Instruction::ExtractValue: {
2829     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
2830     pushValueAndType(I.getOperand(0), InstID, Vals);
2831     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
2832     Vals.append(EVI->idx_begin(), EVI->idx_end());
2833     break;
2834   }
2835   case Instruction::InsertValue: {
2836     Code = bitc::FUNC_CODE_INST_INSERTVAL;
2837     pushValueAndType(I.getOperand(0), InstID, Vals);
2838     pushValueAndType(I.getOperand(1), InstID, Vals);
2839     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
2840     Vals.append(IVI->idx_begin(), IVI->idx_end());
2841     break;
2842   }
2843   case Instruction::Select: {
2844     Code = bitc::FUNC_CODE_INST_VSELECT;
2845     pushValueAndType(I.getOperand(1), InstID, Vals);
2846     pushValue(I.getOperand(2), InstID, Vals);
2847     pushValueAndType(I.getOperand(0), InstID, Vals);
2848     uint64_t Flags = getOptimizationFlags(&I);
2849     if (Flags != 0)
2850       Vals.push_back(Flags);
2851     break;
2852   }
2853   case Instruction::ExtractElement:
2854     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
2855     pushValueAndType(I.getOperand(0), InstID, Vals);
2856     pushValueAndType(I.getOperand(1), InstID, Vals);
2857     break;
2858   case Instruction::InsertElement:
2859     Code = bitc::FUNC_CODE_INST_INSERTELT;
2860     pushValueAndType(I.getOperand(0), InstID, Vals);
2861     pushValue(I.getOperand(1), InstID, Vals);
2862     pushValueAndType(I.getOperand(2), InstID, Vals);
2863     break;
2864   case Instruction::ShuffleVector:
2865     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
2866     pushValueAndType(I.getOperand(0), InstID, Vals);
2867     pushValue(I.getOperand(1), InstID, Vals);
2868     pushValue(cast<ShuffleVectorInst>(I).getShuffleMaskForBitcode(), InstID,
2869               Vals);
2870     break;
2871   case Instruction::ICmp:
2872   case Instruction::FCmp: {
2873     // compare returning Int1Ty or vector of Int1Ty
2874     Code = bitc::FUNC_CODE_INST_CMP2;
2875     pushValueAndType(I.getOperand(0), InstID, Vals);
2876     pushValue(I.getOperand(1), InstID, Vals);
2877     Vals.push_back(cast<CmpInst>(I).getPredicate());
2878     uint64_t Flags = getOptimizationFlags(&I);
2879     if (Flags != 0)
2880       Vals.push_back(Flags);
2881     break;
2882   }
2883 
2884   case Instruction::Ret:
2885     {
2886       Code = bitc::FUNC_CODE_INST_RET;
2887       unsigned NumOperands = I.getNumOperands();
2888       if (NumOperands == 0)
2889         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
2890       else if (NumOperands == 1) {
2891         if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2892           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
2893       } else {
2894         for (unsigned i = 0, e = NumOperands; i != e; ++i)
2895           pushValueAndType(I.getOperand(i), InstID, Vals);
2896       }
2897     }
2898     break;
2899   case Instruction::Br:
2900     {
2901       Code = bitc::FUNC_CODE_INST_BR;
2902       const BranchInst &II = cast<BranchInst>(I);
2903       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
2904       if (II.isConditional()) {
2905         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
2906         pushValue(II.getCondition(), InstID, Vals);
2907       }
2908     }
2909     break;
2910   case Instruction::Switch:
2911     {
2912       Code = bitc::FUNC_CODE_INST_SWITCH;
2913       const SwitchInst &SI = cast<SwitchInst>(I);
2914       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
2915       pushValue(SI.getCondition(), InstID, Vals);
2916       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
2917       for (auto Case : SI.cases()) {
2918         Vals.push_back(VE.getValueID(Case.getCaseValue()));
2919         Vals.push_back(VE.getValueID(Case.getCaseSuccessor()));
2920       }
2921     }
2922     break;
2923   case Instruction::IndirectBr:
2924     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
2925     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2926     // Encode the address operand as relative, but not the basic blocks.
2927     pushValue(I.getOperand(0), InstID, Vals);
2928     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
2929       Vals.push_back(VE.getValueID(I.getOperand(i)));
2930     break;
2931 
2932   case Instruction::Invoke: {
2933     const InvokeInst *II = cast<InvokeInst>(&I);
2934     const Value *Callee = II->getCalledOperand();
2935     FunctionType *FTy = II->getFunctionType();
2936 
2937     if (II->hasOperandBundles())
2938       writeOperandBundles(*II, InstID);
2939 
2940     Code = bitc::FUNC_CODE_INST_INVOKE;
2941 
2942     Vals.push_back(VE.getAttributeListID(II->getAttributes()));
2943     Vals.push_back(II->getCallingConv() | 1 << 13);
2944     Vals.push_back(VE.getValueID(II->getNormalDest()));
2945     Vals.push_back(VE.getValueID(II->getUnwindDest()));
2946     Vals.push_back(VE.getTypeID(FTy));
2947     pushValueAndType(Callee, InstID, Vals);
2948 
2949     // Emit value #'s for the fixed parameters.
2950     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
2951       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
2952 
2953     // Emit type/value pairs for varargs params.
2954     if (FTy->isVarArg()) {
2955       for (unsigned i = FTy->getNumParams(), e = II->arg_size(); i != e; ++i)
2956         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
2957     }
2958     break;
2959   }
2960   case Instruction::Resume:
2961     Code = bitc::FUNC_CODE_INST_RESUME;
2962     pushValueAndType(I.getOperand(0), InstID, Vals);
2963     break;
2964   case Instruction::CleanupRet: {
2965     Code = bitc::FUNC_CODE_INST_CLEANUPRET;
2966     const auto &CRI = cast<CleanupReturnInst>(I);
2967     pushValue(CRI.getCleanupPad(), InstID, Vals);
2968     if (CRI.hasUnwindDest())
2969       Vals.push_back(VE.getValueID(CRI.getUnwindDest()));
2970     break;
2971   }
2972   case Instruction::CatchRet: {
2973     Code = bitc::FUNC_CODE_INST_CATCHRET;
2974     const auto &CRI = cast<CatchReturnInst>(I);
2975     pushValue(CRI.getCatchPad(), InstID, Vals);
2976     Vals.push_back(VE.getValueID(CRI.getSuccessor()));
2977     break;
2978   }
2979   case Instruction::CleanupPad:
2980   case Instruction::CatchPad: {
2981     const auto &FuncletPad = cast<FuncletPadInst>(I);
2982     Code = isa<CatchPadInst>(FuncletPad) ? bitc::FUNC_CODE_INST_CATCHPAD
2983                                          : bitc::FUNC_CODE_INST_CLEANUPPAD;
2984     pushValue(FuncletPad.getParentPad(), InstID, Vals);
2985 
2986     unsigned NumArgOperands = FuncletPad.getNumArgOperands();
2987     Vals.push_back(NumArgOperands);
2988     for (unsigned Op = 0; Op != NumArgOperands; ++Op)
2989       pushValueAndType(FuncletPad.getArgOperand(Op), InstID, Vals);
2990     break;
2991   }
2992   case Instruction::CatchSwitch: {
2993     Code = bitc::FUNC_CODE_INST_CATCHSWITCH;
2994     const auto &CatchSwitch = cast<CatchSwitchInst>(I);
2995 
2996     pushValue(CatchSwitch.getParentPad(), InstID, Vals);
2997 
2998     unsigned NumHandlers = CatchSwitch.getNumHandlers();
2999     Vals.push_back(NumHandlers);
3000     for (const BasicBlock *CatchPadBB : CatchSwitch.handlers())
3001       Vals.push_back(VE.getValueID(CatchPadBB));
3002 
3003     if (CatchSwitch.hasUnwindDest())
3004       Vals.push_back(VE.getValueID(CatchSwitch.getUnwindDest()));
3005     break;
3006   }
3007   case Instruction::CallBr: {
3008     const CallBrInst *CBI = cast<CallBrInst>(&I);
3009     const Value *Callee = CBI->getCalledOperand();
3010     FunctionType *FTy = CBI->getFunctionType();
3011 
3012     if (CBI->hasOperandBundles())
3013       writeOperandBundles(*CBI, InstID);
3014 
3015     Code = bitc::FUNC_CODE_INST_CALLBR;
3016 
3017     Vals.push_back(VE.getAttributeListID(CBI->getAttributes()));
3018 
3019     Vals.push_back(CBI->getCallingConv() << bitc::CALL_CCONV |
3020                    1 << bitc::CALL_EXPLICIT_TYPE);
3021 
3022     Vals.push_back(VE.getValueID(CBI->getDefaultDest()));
3023     Vals.push_back(CBI->getNumIndirectDests());
3024     for (unsigned i = 0, e = CBI->getNumIndirectDests(); i != e; ++i)
3025       Vals.push_back(VE.getValueID(CBI->getIndirectDest(i)));
3026 
3027     Vals.push_back(VE.getTypeID(FTy));
3028     pushValueAndType(Callee, InstID, Vals);
3029 
3030     // Emit value #'s for the fixed parameters.
3031     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
3032       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
3033 
3034     // Emit type/value pairs for varargs params.
3035     if (FTy->isVarArg()) {
3036       for (unsigned i = FTy->getNumParams(), e = CBI->arg_size(); i != e; ++i)
3037         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
3038     }
3039     break;
3040   }
3041   case Instruction::Unreachable:
3042     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
3043     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
3044     break;
3045 
3046   case Instruction::PHI: {
3047     const PHINode &PN = cast<PHINode>(I);
3048     Code = bitc::FUNC_CODE_INST_PHI;
3049     // With the newer instruction encoding, forward references could give
3050     // negative valued IDs.  This is most common for PHIs, so we use
3051     // signed VBRs.
3052     SmallVector<uint64_t, 128> Vals64;
3053     Vals64.push_back(VE.getTypeID(PN.getType()));
3054     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
3055       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64);
3056       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
3057     }
3058 
3059     uint64_t Flags = getOptimizationFlags(&I);
3060     if (Flags != 0)
3061       Vals64.push_back(Flags);
3062 
3063     // Emit a Vals64 vector and exit.
3064     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
3065     Vals64.clear();
3066     return;
3067   }
3068 
3069   case Instruction::LandingPad: {
3070     const LandingPadInst &LP = cast<LandingPadInst>(I);
3071     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
3072     Vals.push_back(VE.getTypeID(LP.getType()));
3073     Vals.push_back(LP.isCleanup());
3074     Vals.push_back(LP.getNumClauses());
3075     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
3076       if (LP.isCatch(I))
3077         Vals.push_back(LandingPadInst::Catch);
3078       else
3079         Vals.push_back(LandingPadInst::Filter);
3080       pushValueAndType(LP.getClause(I), InstID, Vals);
3081     }
3082     break;
3083   }
3084 
3085   case Instruction::Alloca: {
3086     Code = bitc::FUNC_CODE_INST_ALLOCA;
3087     const AllocaInst &AI = cast<AllocaInst>(I);
3088     Vals.push_back(VE.getTypeID(AI.getAllocatedType()));
3089     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
3090     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
3091     using APV = AllocaPackedValues;
3092     unsigned Record = 0;
3093     unsigned EncodedAlign = getEncodedAlign(AI.getAlign());
3094     Bitfield::set<APV::AlignLower>(
3095         Record, EncodedAlign & ((1 << APV::AlignLower::Bits) - 1));
3096     Bitfield::set<APV::AlignUpper>(Record,
3097                                    EncodedAlign >> APV::AlignLower::Bits);
3098     Bitfield::set<APV::UsedWithInAlloca>(Record, AI.isUsedWithInAlloca());
3099     Bitfield::set<APV::ExplicitType>(Record, true);
3100     Bitfield::set<APV::SwiftError>(Record, AI.isSwiftError());
3101     Vals.push_back(Record);
3102 
3103     unsigned AS = AI.getAddressSpace();
3104     if (AS != M.getDataLayout().getAllocaAddrSpace())
3105       Vals.push_back(AS);
3106     break;
3107   }
3108 
3109   case Instruction::Load:
3110     if (cast<LoadInst>(I).isAtomic()) {
3111       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
3112       pushValueAndType(I.getOperand(0), InstID, Vals);
3113     } else {
3114       Code = bitc::FUNC_CODE_INST_LOAD;
3115       if (!pushValueAndType(I.getOperand(0), InstID, Vals)) // ptr
3116         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
3117     }
3118     Vals.push_back(VE.getTypeID(I.getType()));
3119     Vals.push_back(getEncodedAlign(cast<LoadInst>(I).getAlign()));
3120     Vals.push_back(cast<LoadInst>(I).isVolatile());
3121     if (cast<LoadInst>(I).isAtomic()) {
3122       Vals.push_back(getEncodedOrdering(cast<LoadInst>(I).getOrdering()));
3123       Vals.push_back(getEncodedSyncScopeID(cast<LoadInst>(I).getSyncScopeID()));
3124     }
3125     break;
3126   case Instruction::Store:
3127     if (cast<StoreInst>(I).isAtomic())
3128       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
3129     else
3130       Code = bitc::FUNC_CODE_INST_STORE;
3131     pushValueAndType(I.getOperand(1), InstID, Vals); // ptrty + ptr
3132     pushValueAndType(I.getOperand(0), InstID, Vals); // valty + val
3133     Vals.push_back(getEncodedAlign(cast<StoreInst>(I).getAlign()));
3134     Vals.push_back(cast<StoreInst>(I).isVolatile());
3135     if (cast<StoreInst>(I).isAtomic()) {
3136       Vals.push_back(getEncodedOrdering(cast<StoreInst>(I).getOrdering()));
3137       Vals.push_back(
3138           getEncodedSyncScopeID(cast<StoreInst>(I).getSyncScopeID()));
3139     }
3140     break;
3141   case Instruction::AtomicCmpXchg:
3142     Code = bitc::FUNC_CODE_INST_CMPXCHG;
3143     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
3144     pushValueAndType(I.getOperand(1), InstID, Vals); // cmp.
3145     pushValue(I.getOperand(2), InstID, Vals);        // newval.
3146     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
3147     Vals.push_back(
3148         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
3149     Vals.push_back(
3150         getEncodedSyncScopeID(cast<AtomicCmpXchgInst>(I).getSyncScopeID()));
3151     Vals.push_back(
3152         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
3153     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
3154     Vals.push_back(getEncodedAlign(cast<AtomicCmpXchgInst>(I).getAlign()));
3155     break;
3156   case Instruction::AtomicRMW:
3157     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
3158     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
3159     pushValueAndType(I.getOperand(1), InstID, Vals); // valty + val
3160     Vals.push_back(
3161         getEncodedRMWOperation(cast<AtomicRMWInst>(I).getOperation()));
3162     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
3163     Vals.push_back(getEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
3164     Vals.push_back(
3165         getEncodedSyncScopeID(cast<AtomicRMWInst>(I).getSyncScopeID()));
3166     Vals.push_back(getEncodedAlign(cast<AtomicRMWInst>(I).getAlign()));
3167     break;
3168   case Instruction::Fence:
3169     Code = bitc::FUNC_CODE_INST_FENCE;
3170     Vals.push_back(getEncodedOrdering(cast<FenceInst>(I).getOrdering()));
3171     Vals.push_back(getEncodedSyncScopeID(cast<FenceInst>(I).getSyncScopeID()));
3172     break;
3173   case Instruction::Call: {
3174     const CallInst &CI = cast<CallInst>(I);
3175     FunctionType *FTy = CI.getFunctionType();
3176 
3177     if (CI.hasOperandBundles())
3178       writeOperandBundles(CI, InstID);
3179 
3180     Code = bitc::FUNC_CODE_INST_CALL;
3181 
3182     Vals.push_back(VE.getAttributeListID(CI.getAttributes()));
3183 
3184     unsigned Flags = getOptimizationFlags(&I);
3185     Vals.push_back(CI.getCallingConv() << bitc::CALL_CCONV |
3186                    unsigned(CI.isTailCall()) << bitc::CALL_TAIL |
3187                    unsigned(CI.isMustTailCall()) << bitc::CALL_MUSTTAIL |
3188                    1 << bitc::CALL_EXPLICIT_TYPE |
3189                    unsigned(CI.isNoTailCall()) << bitc::CALL_NOTAIL |
3190                    unsigned(Flags != 0) << bitc::CALL_FMF);
3191     if (Flags != 0)
3192       Vals.push_back(Flags);
3193 
3194     Vals.push_back(VE.getTypeID(FTy));
3195     pushValueAndType(CI.getCalledOperand(), InstID, Vals); // Callee
3196 
3197     // Emit value #'s for the fixed parameters.
3198     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
3199       // Check for labels (can happen with asm labels).
3200       if (FTy->getParamType(i)->isLabelTy())
3201         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
3202       else
3203         pushValue(CI.getArgOperand(i), InstID, Vals); // fixed param.
3204     }
3205 
3206     // Emit type/value pairs for varargs params.
3207     if (FTy->isVarArg()) {
3208       for (unsigned i = FTy->getNumParams(), e = CI.arg_size(); i != e; ++i)
3209         pushValueAndType(CI.getArgOperand(i), InstID, Vals); // varargs
3210     }
3211     break;
3212   }
3213   case Instruction::VAArg:
3214     Code = bitc::FUNC_CODE_INST_VAARG;
3215     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
3216     pushValue(I.getOperand(0), InstID, Vals);                   // valist.
3217     Vals.push_back(VE.getTypeID(I.getType())); // restype.
3218     break;
3219   case Instruction::Freeze:
3220     Code = bitc::FUNC_CODE_INST_FREEZE;
3221     pushValueAndType(I.getOperand(0), InstID, Vals);
3222     break;
3223   }
3224 
3225   Stream.EmitRecord(Code, Vals, AbbrevToUse);
3226   Vals.clear();
3227 }
3228 
3229 /// Write a GlobalValue VST to the module. The purpose of this data structure is
3230 /// to allow clients to efficiently find the function body.
3231 void ModuleBitcodeWriter::writeGlobalValueSymbolTable(
3232   DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3233   // Get the offset of the VST we are writing, and backpatch it into
3234   // the VST forward declaration record.
3235   uint64_t VSTOffset = Stream.GetCurrentBitNo();
3236   // The BitcodeStartBit was the stream offset of the identification block.
3237   VSTOffset -= bitcodeStartBit();
3238   assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
3239   // Note that we add 1 here because the offset is relative to one word
3240   // before the start of the identification block, which was historically
3241   // always the start of the regular bitcode header.
3242   Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32 + 1);
3243 
3244   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3245 
3246   auto Abbv = std::make_shared<BitCodeAbbrev>();
3247   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
3248   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
3249   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
3250   unsigned FnEntryAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3251 
3252   for (const Function &F : M) {
3253     uint64_t Record[2];
3254 
3255     if (F.isDeclaration())
3256       continue;
3257 
3258     Record[0] = VE.getValueID(&F);
3259 
3260     // Save the word offset of the function (from the start of the
3261     // actual bitcode written to the stream).
3262     uint64_t BitcodeIndex = FunctionToBitcodeIndex[&F] - bitcodeStartBit();
3263     assert((BitcodeIndex & 31) == 0 && "function block not 32-bit aligned");
3264     // Note that we add 1 here because the offset is relative to one word
3265     // before the start of the identification block, which was historically
3266     // always the start of the regular bitcode header.
3267     Record[1] = BitcodeIndex / 32 + 1;
3268 
3269     Stream.EmitRecord(bitc::VST_CODE_FNENTRY, Record, FnEntryAbbrev);
3270   }
3271 
3272   Stream.ExitBlock();
3273 }
3274 
3275 /// Emit names for arguments, instructions and basic blocks in a function.
3276 void ModuleBitcodeWriter::writeFunctionLevelValueSymbolTable(
3277     const ValueSymbolTable &VST) {
3278   if (VST.empty())
3279     return;
3280 
3281   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3282 
3283   // FIXME: Set up the abbrev, we know how many values there are!
3284   // FIXME: We know if the type names can use 7-bit ascii.
3285   SmallVector<uint64_t, 64> NameVals;
3286 
3287   for (const ValueName &Name : VST) {
3288     // Figure out the encoding to use for the name.
3289     StringEncoding Bits = getStringEncoding(Name.getKey());
3290 
3291     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
3292     NameVals.push_back(VE.getValueID(Name.getValue()));
3293 
3294     // VST_CODE_ENTRY:   [valueid, namechar x N]
3295     // VST_CODE_BBENTRY: [bbid, namechar x N]
3296     unsigned Code;
3297     if (isa<BasicBlock>(Name.getValue())) {
3298       Code = bitc::VST_CODE_BBENTRY;
3299       if (Bits == SE_Char6)
3300         AbbrevToUse = VST_BBENTRY_6_ABBREV;
3301     } else {
3302       Code = bitc::VST_CODE_ENTRY;
3303       if (Bits == SE_Char6)
3304         AbbrevToUse = VST_ENTRY_6_ABBREV;
3305       else if (Bits == SE_Fixed7)
3306         AbbrevToUse = VST_ENTRY_7_ABBREV;
3307     }
3308 
3309     for (const auto P : Name.getKey())
3310       NameVals.push_back((unsigned char)P);
3311 
3312     // Emit the finished record.
3313     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
3314     NameVals.clear();
3315   }
3316 
3317   Stream.ExitBlock();
3318 }
3319 
3320 void ModuleBitcodeWriter::writeUseList(UseListOrder &&Order) {
3321   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
3322   unsigned Code;
3323   if (isa<BasicBlock>(Order.V))
3324     Code = bitc::USELIST_CODE_BB;
3325   else
3326     Code = bitc::USELIST_CODE_DEFAULT;
3327 
3328   SmallVector<uint64_t, 64> Record(Order.Shuffle.begin(), Order.Shuffle.end());
3329   Record.push_back(VE.getValueID(Order.V));
3330   Stream.EmitRecord(Code, Record);
3331 }
3332 
3333 void ModuleBitcodeWriter::writeUseListBlock(const Function *F) {
3334   assert(VE.shouldPreserveUseListOrder() &&
3335          "Expected to be preserving use-list order");
3336 
3337   auto hasMore = [&]() {
3338     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
3339   };
3340   if (!hasMore())
3341     // Nothing to do.
3342     return;
3343 
3344   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
3345   while (hasMore()) {
3346     writeUseList(std::move(VE.UseListOrders.back()));
3347     VE.UseListOrders.pop_back();
3348   }
3349   Stream.ExitBlock();
3350 }
3351 
3352 /// Emit a function body to the module stream.
3353 void ModuleBitcodeWriter::writeFunction(
3354     const Function &F,
3355     DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3356   // Save the bitcode index of the start of this function block for recording
3357   // in the VST.
3358   FunctionToBitcodeIndex[&F] = Stream.GetCurrentBitNo();
3359 
3360   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
3361   VE.incorporateFunction(F);
3362 
3363   SmallVector<unsigned, 64> Vals;
3364 
3365   // Emit the number of basic blocks, so the reader can create them ahead of
3366   // time.
3367   Vals.push_back(VE.getBasicBlocks().size());
3368   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
3369   Vals.clear();
3370 
3371   // If there are function-local constants, emit them now.
3372   unsigned CstStart, CstEnd;
3373   VE.getFunctionConstantRange(CstStart, CstEnd);
3374   writeConstants(CstStart, CstEnd, false);
3375 
3376   // If there is function-local metadata, emit it now.
3377   writeFunctionMetadata(F);
3378 
3379   // Keep a running idea of what the instruction ID is.
3380   unsigned InstID = CstEnd;
3381 
3382   bool NeedsMetadataAttachment = F.hasMetadata();
3383 
3384   DILocation *LastDL = nullptr;
3385   SmallSetVector<Function *, 4> BlockAddressUsers;
3386 
3387   // Finally, emit all the instructions, in order.
3388   for (const BasicBlock &BB : F) {
3389     for (const Instruction &I : BB) {
3390       writeInstruction(I, InstID, Vals);
3391 
3392       if (!I.getType()->isVoidTy())
3393         ++InstID;
3394 
3395       // If the instruction has metadata, write a metadata attachment later.
3396       NeedsMetadataAttachment |= I.hasMetadataOtherThanDebugLoc();
3397 
3398       // If the instruction has a debug location, emit it.
3399       DILocation *DL = I.getDebugLoc();
3400       if (!DL)
3401         continue;
3402 
3403       if (DL == LastDL) {
3404         // Just repeat the same debug loc as last time.
3405         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
3406         continue;
3407       }
3408 
3409       Vals.push_back(DL->getLine());
3410       Vals.push_back(DL->getColumn());
3411       Vals.push_back(VE.getMetadataOrNullID(DL->getScope()));
3412       Vals.push_back(VE.getMetadataOrNullID(DL->getInlinedAt()));
3413       Vals.push_back(DL->isImplicitCode());
3414       Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
3415       Vals.clear();
3416 
3417       LastDL = DL;
3418     }
3419 
3420     if (BlockAddress *BA = BlockAddress::lookup(&BB)) {
3421       SmallVector<Value *> Worklist{BA};
3422       SmallPtrSet<Value *, 8> Visited{BA};
3423       while (!Worklist.empty()) {
3424         Value *V = Worklist.pop_back_val();
3425         for (User *U : V->users()) {
3426           if (auto *I = dyn_cast<Instruction>(U)) {
3427             Function *P = I->getFunction();
3428             if (P != &F)
3429               BlockAddressUsers.insert(P);
3430           } else if (isa<Constant>(U) && !isa<GlobalValue>(U) &&
3431                      Visited.insert(U).second)
3432             Worklist.push_back(U);
3433         }
3434       }
3435     }
3436   }
3437 
3438   if (!BlockAddressUsers.empty()) {
3439     Vals.resize(BlockAddressUsers.size());
3440     for (auto I : llvm::enumerate(BlockAddressUsers))
3441       Vals[I.index()] = VE.getValueID(I.value());
3442     Stream.EmitRecord(bitc::FUNC_CODE_BLOCKADDR_USERS, Vals);
3443     Vals.clear();
3444   }
3445 
3446   // Emit names for all the instructions etc.
3447   if (auto *Symtab = F.getValueSymbolTable())
3448     writeFunctionLevelValueSymbolTable(*Symtab);
3449 
3450   if (NeedsMetadataAttachment)
3451     writeFunctionMetadataAttachment(F);
3452   if (VE.shouldPreserveUseListOrder())
3453     writeUseListBlock(&F);
3454   VE.purgeFunction();
3455   Stream.ExitBlock();
3456 }
3457 
3458 // Emit blockinfo, which defines the standard abbreviations etc.
3459 void ModuleBitcodeWriter::writeBlockInfo() {
3460   // We only want to emit block info records for blocks that have multiple
3461   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
3462   // Other blocks can define their abbrevs inline.
3463   Stream.EnterBlockInfoBlock();
3464 
3465   { // 8-bit fixed-width VST_CODE_ENTRY/VST_CODE_BBENTRY strings.
3466     auto Abbv = std::make_shared<BitCodeAbbrev>();
3467     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
3468     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3469     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3470     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3471     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3472         VST_ENTRY_8_ABBREV)
3473       llvm_unreachable("Unexpected abbrev ordering!");
3474   }
3475 
3476   { // 7-bit fixed width VST_CODE_ENTRY strings.
3477     auto Abbv = std::make_shared<BitCodeAbbrev>();
3478     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3479     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3480     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3481     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3482     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3483         VST_ENTRY_7_ABBREV)
3484       llvm_unreachable("Unexpected abbrev ordering!");
3485   }
3486   { // 6-bit char6 VST_CODE_ENTRY strings.
3487     auto Abbv = std::make_shared<BitCodeAbbrev>();
3488     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3489     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3490     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3491     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3492     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3493         VST_ENTRY_6_ABBREV)
3494       llvm_unreachable("Unexpected abbrev ordering!");
3495   }
3496   { // 6-bit char6 VST_CODE_BBENTRY strings.
3497     auto Abbv = std::make_shared<BitCodeAbbrev>();
3498     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
3499     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3500     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3501     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3502     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3503         VST_BBENTRY_6_ABBREV)
3504       llvm_unreachable("Unexpected abbrev ordering!");
3505   }
3506 
3507   { // SETTYPE abbrev for CONSTANTS_BLOCK.
3508     auto Abbv = std::make_shared<BitCodeAbbrev>();
3509     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
3510     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
3511                               VE.computeBitsRequiredForTypeIndicies()));
3512     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3513         CONSTANTS_SETTYPE_ABBREV)
3514       llvm_unreachable("Unexpected abbrev ordering!");
3515   }
3516 
3517   { // INTEGER abbrev for CONSTANTS_BLOCK.
3518     auto Abbv = std::make_shared<BitCodeAbbrev>();
3519     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
3520     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3521     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3522         CONSTANTS_INTEGER_ABBREV)
3523       llvm_unreachable("Unexpected abbrev ordering!");
3524   }
3525 
3526   { // CE_CAST abbrev for CONSTANTS_BLOCK.
3527     auto Abbv = std::make_shared<BitCodeAbbrev>();
3528     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
3529     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
3530     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
3531                               VE.computeBitsRequiredForTypeIndicies()));
3532     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
3533 
3534     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3535         CONSTANTS_CE_CAST_Abbrev)
3536       llvm_unreachable("Unexpected abbrev ordering!");
3537   }
3538   { // NULL abbrev for CONSTANTS_BLOCK.
3539     auto Abbv = std::make_shared<BitCodeAbbrev>();
3540     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
3541     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3542         CONSTANTS_NULL_Abbrev)
3543       llvm_unreachable("Unexpected abbrev ordering!");
3544   }
3545 
3546   // FIXME: This should only use space for first class types!
3547 
3548   { // INST_LOAD abbrev for FUNCTION_BLOCK.
3549     auto Abbv = std::make_shared<BitCodeAbbrev>();
3550     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
3551     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
3552     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
3553                               VE.computeBitsRequiredForTypeIndicies()));
3554     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
3555     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
3556     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3557         FUNCTION_INST_LOAD_ABBREV)
3558       llvm_unreachable("Unexpected abbrev ordering!");
3559   }
3560   { // INST_UNOP abbrev for FUNCTION_BLOCK.
3561     auto Abbv = std::make_shared<BitCodeAbbrev>();
3562     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3563     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3564     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3565     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3566         FUNCTION_INST_UNOP_ABBREV)
3567       llvm_unreachable("Unexpected abbrev ordering!");
3568   }
3569   { // INST_UNOP_FLAGS abbrev for FUNCTION_BLOCK.
3570     auto Abbv = std::make_shared<BitCodeAbbrev>();
3571     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3572     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3573     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3574     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3575     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3576         FUNCTION_INST_UNOP_FLAGS_ABBREV)
3577       llvm_unreachable("Unexpected abbrev ordering!");
3578   }
3579   { // INST_BINOP abbrev for FUNCTION_BLOCK.
3580     auto Abbv = std::make_shared<BitCodeAbbrev>();
3581     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3582     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3583     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3584     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3585     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3586         FUNCTION_INST_BINOP_ABBREV)
3587       llvm_unreachable("Unexpected abbrev ordering!");
3588   }
3589   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
3590     auto Abbv = std::make_shared<BitCodeAbbrev>();
3591     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3592     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3593     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3594     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3595     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3596     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3597         FUNCTION_INST_BINOP_FLAGS_ABBREV)
3598       llvm_unreachable("Unexpected abbrev ordering!");
3599   }
3600   { // INST_CAST abbrev for FUNCTION_BLOCK.
3601     auto Abbv = std::make_shared<BitCodeAbbrev>();
3602     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
3603     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
3604     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
3605                               VE.computeBitsRequiredForTypeIndicies()));
3606     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
3607     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3608         FUNCTION_INST_CAST_ABBREV)
3609       llvm_unreachable("Unexpected abbrev ordering!");
3610   }
3611 
3612   { // INST_RET abbrev for FUNCTION_BLOCK.
3613     auto Abbv = std::make_shared<BitCodeAbbrev>();
3614     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3615     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3616         FUNCTION_INST_RET_VOID_ABBREV)
3617       llvm_unreachable("Unexpected abbrev ordering!");
3618   }
3619   { // INST_RET abbrev for FUNCTION_BLOCK.
3620     auto Abbv = std::make_shared<BitCodeAbbrev>();
3621     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3622     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
3623     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3624         FUNCTION_INST_RET_VAL_ABBREV)
3625       llvm_unreachable("Unexpected abbrev ordering!");
3626   }
3627   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
3628     auto Abbv = std::make_shared<BitCodeAbbrev>();
3629     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
3630     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3631         FUNCTION_INST_UNREACHABLE_ABBREV)
3632       llvm_unreachable("Unexpected abbrev ordering!");
3633   }
3634   {
3635     auto Abbv = std::make_shared<BitCodeAbbrev>();
3636     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_GEP));
3637     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
3638     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, // dest ty
3639                               Log2_32_Ceil(VE.getTypes().size() + 1)));
3640     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3641     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
3642     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3643         FUNCTION_INST_GEP_ABBREV)
3644       llvm_unreachable("Unexpected abbrev ordering!");
3645   }
3646 
3647   Stream.ExitBlock();
3648 }
3649 
3650 /// Write the module path strings, currently only used when generating
3651 /// a combined index file.
3652 void IndexBitcodeWriter::writeModStrings() {
3653   Stream.EnterSubblock(bitc::MODULE_STRTAB_BLOCK_ID, 3);
3654 
3655   // TODO: See which abbrev sizes we actually need to emit
3656 
3657   // 8-bit fixed-width MST_ENTRY strings.
3658   auto Abbv = std::make_shared<BitCodeAbbrev>();
3659   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3660   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3661   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3662   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3663   unsigned Abbrev8Bit = Stream.EmitAbbrev(std::move(Abbv));
3664 
3665   // 7-bit fixed width MST_ENTRY strings.
3666   Abbv = std::make_shared<BitCodeAbbrev>();
3667   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3668   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3669   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3670   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3671   unsigned Abbrev7Bit = Stream.EmitAbbrev(std::move(Abbv));
3672 
3673   // 6-bit char6 MST_ENTRY strings.
3674   Abbv = std::make_shared<BitCodeAbbrev>();
3675   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3676   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3677   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3678   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3679   unsigned Abbrev6Bit = Stream.EmitAbbrev(std::move(Abbv));
3680 
3681   // Module Hash, 160 bits SHA1. Optionally, emitted after each MST_CODE_ENTRY.
3682   Abbv = std::make_shared<BitCodeAbbrev>();
3683   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_HASH));
3684   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3685   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3686   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3687   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3688   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3689   unsigned AbbrevHash = Stream.EmitAbbrev(std::move(Abbv));
3690 
3691   SmallVector<unsigned, 64> Vals;
3692   forEachModule(
3693       [&](const StringMapEntry<std::pair<uint64_t, ModuleHash>> &MPSE) {
3694         StringRef Key = MPSE.getKey();
3695         const auto &Value = MPSE.getValue();
3696         StringEncoding Bits = getStringEncoding(Key);
3697         unsigned AbbrevToUse = Abbrev8Bit;
3698         if (Bits == SE_Char6)
3699           AbbrevToUse = Abbrev6Bit;
3700         else if (Bits == SE_Fixed7)
3701           AbbrevToUse = Abbrev7Bit;
3702 
3703         Vals.push_back(Value.first);
3704         Vals.append(Key.begin(), Key.end());
3705 
3706         // Emit the finished record.
3707         Stream.EmitRecord(bitc::MST_CODE_ENTRY, Vals, AbbrevToUse);
3708 
3709         // Emit an optional hash for the module now
3710         const auto &Hash = Value.second;
3711         if (llvm::any_of(Hash, [](uint32_t H) { return H; })) {
3712           Vals.assign(Hash.begin(), Hash.end());
3713           // Emit the hash record.
3714           Stream.EmitRecord(bitc::MST_CODE_HASH, Vals, AbbrevHash);
3715         }
3716 
3717         Vals.clear();
3718       });
3719   Stream.ExitBlock();
3720 }
3721 
3722 /// Write the function type metadata related records that need to appear before
3723 /// a function summary entry (whether per-module or combined).
3724 template <typename Fn>
3725 static void writeFunctionTypeMetadataRecords(BitstreamWriter &Stream,
3726                                              FunctionSummary *FS,
3727                                              Fn GetValueID) {
3728   if (!FS->type_tests().empty())
3729     Stream.EmitRecord(bitc::FS_TYPE_TESTS, FS->type_tests());
3730 
3731   SmallVector<uint64_t, 64> Record;
3732 
3733   auto WriteVFuncIdVec = [&](uint64_t Ty,
3734                              ArrayRef<FunctionSummary::VFuncId> VFs) {
3735     if (VFs.empty())
3736       return;
3737     Record.clear();
3738     for (auto &VF : VFs) {
3739       Record.push_back(VF.GUID);
3740       Record.push_back(VF.Offset);
3741     }
3742     Stream.EmitRecord(Ty, Record);
3743   };
3744 
3745   WriteVFuncIdVec(bitc::FS_TYPE_TEST_ASSUME_VCALLS,
3746                   FS->type_test_assume_vcalls());
3747   WriteVFuncIdVec(bitc::FS_TYPE_CHECKED_LOAD_VCALLS,
3748                   FS->type_checked_load_vcalls());
3749 
3750   auto WriteConstVCallVec = [&](uint64_t Ty,
3751                                 ArrayRef<FunctionSummary::ConstVCall> VCs) {
3752     for (auto &VC : VCs) {
3753       Record.clear();
3754       Record.push_back(VC.VFunc.GUID);
3755       Record.push_back(VC.VFunc.Offset);
3756       llvm::append_range(Record, VC.Args);
3757       Stream.EmitRecord(Ty, Record);
3758     }
3759   };
3760 
3761   WriteConstVCallVec(bitc::FS_TYPE_TEST_ASSUME_CONST_VCALL,
3762                      FS->type_test_assume_const_vcalls());
3763   WriteConstVCallVec(bitc::FS_TYPE_CHECKED_LOAD_CONST_VCALL,
3764                      FS->type_checked_load_const_vcalls());
3765 
3766   auto WriteRange = [&](ConstantRange Range) {
3767     Range = Range.sextOrTrunc(FunctionSummary::ParamAccess::RangeWidth);
3768     assert(Range.getLower().getNumWords() == 1);
3769     assert(Range.getUpper().getNumWords() == 1);
3770     emitSignedInt64(Record, *Range.getLower().getRawData());
3771     emitSignedInt64(Record, *Range.getUpper().getRawData());
3772   };
3773 
3774   if (!FS->paramAccesses().empty()) {
3775     Record.clear();
3776     for (auto &Arg : FS->paramAccesses()) {
3777       size_t UndoSize = Record.size();
3778       Record.push_back(Arg.ParamNo);
3779       WriteRange(Arg.Use);
3780       Record.push_back(Arg.Calls.size());
3781       for (auto &Call : Arg.Calls) {
3782         Record.push_back(Call.ParamNo);
3783         Optional<unsigned> ValueID = GetValueID(Call.Callee);
3784         if (!ValueID) {
3785           // If ValueID is unknown we can't drop just this call, we must drop
3786           // entire parameter.
3787           Record.resize(UndoSize);
3788           break;
3789         }
3790         Record.push_back(*ValueID);
3791         WriteRange(Call.Offsets);
3792       }
3793     }
3794     if (!Record.empty())
3795       Stream.EmitRecord(bitc::FS_PARAM_ACCESS, Record);
3796   }
3797 }
3798 
3799 /// Collect type IDs from type tests used by function.
3800 static void
3801 getReferencedTypeIds(FunctionSummary *FS,
3802                      std::set<GlobalValue::GUID> &ReferencedTypeIds) {
3803   if (!FS->type_tests().empty())
3804     for (auto &TT : FS->type_tests())
3805       ReferencedTypeIds.insert(TT);
3806 
3807   auto GetReferencedTypesFromVFuncIdVec =
3808       [&](ArrayRef<FunctionSummary::VFuncId> VFs) {
3809         for (auto &VF : VFs)
3810           ReferencedTypeIds.insert(VF.GUID);
3811       };
3812 
3813   GetReferencedTypesFromVFuncIdVec(FS->type_test_assume_vcalls());
3814   GetReferencedTypesFromVFuncIdVec(FS->type_checked_load_vcalls());
3815 
3816   auto GetReferencedTypesFromConstVCallVec =
3817       [&](ArrayRef<FunctionSummary::ConstVCall> VCs) {
3818         for (auto &VC : VCs)
3819           ReferencedTypeIds.insert(VC.VFunc.GUID);
3820       };
3821 
3822   GetReferencedTypesFromConstVCallVec(FS->type_test_assume_const_vcalls());
3823   GetReferencedTypesFromConstVCallVec(FS->type_checked_load_const_vcalls());
3824 }
3825 
3826 static void writeWholeProgramDevirtResolutionByArg(
3827     SmallVector<uint64_t, 64> &NameVals, const std::vector<uint64_t> &args,
3828     const WholeProgramDevirtResolution::ByArg &ByArg) {
3829   NameVals.push_back(args.size());
3830   llvm::append_range(NameVals, args);
3831 
3832   NameVals.push_back(ByArg.TheKind);
3833   NameVals.push_back(ByArg.Info);
3834   NameVals.push_back(ByArg.Byte);
3835   NameVals.push_back(ByArg.Bit);
3836 }
3837 
3838 static void writeWholeProgramDevirtResolution(
3839     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3840     uint64_t Id, const WholeProgramDevirtResolution &Wpd) {
3841   NameVals.push_back(Id);
3842 
3843   NameVals.push_back(Wpd.TheKind);
3844   NameVals.push_back(StrtabBuilder.add(Wpd.SingleImplName));
3845   NameVals.push_back(Wpd.SingleImplName.size());
3846 
3847   NameVals.push_back(Wpd.ResByArg.size());
3848   for (auto &A : Wpd.ResByArg)
3849     writeWholeProgramDevirtResolutionByArg(NameVals, A.first, A.second);
3850 }
3851 
3852 static void writeTypeIdSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
3853                                      StringTableBuilder &StrtabBuilder,
3854                                      const std::string &Id,
3855                                      const TypeIdSummary &Summary) {
3856   NameVals.push_back(StrtabBuilder.add(Id));
3857   NameVals.push_back(Id.size());
3858 
3859   NameVals.push_back(Summary.TTRes.TheKind);
3860   NameVals.push_back(Summary.TTRes.SizeM1BitWidth);
3861   NameVals.push_back(Summary.TTRes.AlignLog2);
3862   NameVals.push_back(Summary.TTRes.SizeM1);
3863   NameVals.push_back(Summary.TTRes.BitMask);
3864   NameVals.push_back(Summary.TTRes.InlineBits);
3865 
3866   for (auto &W : Summary.WPDRes)
3867     writeWholeProgramDevirtResolution(NameVals, StrtabBuilder, W.first,
3868                                       W.second);
3869 }
3870 
3871 static void writeTypeIdCompatibleVtableSummaryRecord(
3872     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3873     const std::string &Id, const TypeIdCompatibleVtableInfo &Summary,
3874     ValueEnumerator &VE) {
3875   NameVals.push_back(StrtabBuilder.add(Id));
3876   NameVals.push_back(Id.size());
3877 
3878   for (auto &P : Summary) {
3879     NameVals.push_back(P.AddressPointOffset);
3880     NameVals.push_back(VE.getValueID(P.VTableVI.getValue()));
3881   }
3882 }
3883 
3884 // Helper to emit a single function summary record.
3885 void ModuleBitcodeWriterBase::writePerModuleFunctionSummaryRecord(
3886     SmallVector<uint64_t, 64> &NameVals, GlobalValueSummary *Summary,
3887     unsigned ValueID, unsigned FSCallsAbbrev, unsigned FSCallsProfileAbbrev,
3888     const Function &F) {
3889   NameVals.push_back(ValueID);
3890 
3891   FunctionSummary *FS = cast<FunctionSummary>(Summary);
3892 
3893   writeFunctionTypeMetadataRecords(
3894       Stream, FS, [&](const ValueInfo &VI) -> Optional<unsigned> {
3895         return {VE.getValueID(VI.getValue())};
3896       });
3897 
3898   auto SpecialRefCnts = FS->specialRefCounts();
3899   NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
3900   NameVals.push_back(FS->instCount());
3901   NameVals.push_back(getEncodedFFlags(FS->fflags()));
3902   NameVals.push_back(FS->refs().size());
3903   NameVals.push_back(SpecialRefCnts.first);  // rorefcnt
3904   NameVals.push_back(SpecialRefCnts.second); // worefcnt
3905 
3906   for (auto &RI : FS->refs())
3907     NameVals.push_back(VE.getValueID(RI.getValue()));
3908 
3909   bool HasProfileData =
3910       F.hasProfileData() || ForceSummaryEdgesCold != FunctionSummary::FSHT_None;
3911   for (auto &ECI : FS->calls()) {
3912     NameVals.push_back(getValueId(ECI.first));
3913     if (HasProfileData)
3914       NameVals.push_back(static_cast<uint8_t>(ECI.second.Hotness));
3915     else if (WriteRelBFToSummary)
3916       NameVals.push_back(ECI.second.RelBlockFreq);
3917   }
3918 
3919   unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
3920   unsigned Code =
3921       (HasProfileData ? bitc::FS_PERMODULE_PROFILE
3922                       : (WriteRelBFToSummary ? bitc::FS_PERMODULE_RELBF
3923                                              : bitc::FS_PERMODULE));
3924 
3925   // Emit the finished record.
3926   Stream.EmitRecord(Code, NameVals, FSAbbrev);
3927   NameVals.clear();
3928 }
3929 
3930 // Collect the global value references in the given variable's initializer,
3931 // and emit them in a summary record.
3932 void ModuleBitcodeWriterBase::writeModuleLevelReferences(
3933     const GlobalVariable &V, SmallVector<uint64_t, 64> &NameVals,
3934     unsigned FSModRefsAbbrev, unsigned FSModVTableRefsAbbrev) {
3935   auto VI = Index->getValueInfo(V.getGUID());
3936   if (!VI || VI.getSummaryList().empty()) {
3937     // Only declarations should not have a summary (a declaration might however
3938     // have a summary if the def was in module level asm).
3939     assert(V.isDeclaration());
3940     return;
3941   }
3942   auto *Summary = VI.getSummaryList()[0].get();
3943   NameVals.push_back(VE.getValueID(&V));
3944   GlobalVarSummary *VS = cast<GlobalVarSummary>(Summary);
3945   NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
3946   NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
3947 
3948   auto VTableFuncs = VS->vTableFuncs();
3949   if (!VTableFuncs.empty())
3950     NameVals.push_back(VS->refs().size());
3951 
3952   unsigned SizeBeforeRefs = NameVals.size();
3953   for (auto &RI : VS->refs())
3954     NameVals.push_back(VE.getValueID(RI.getValue()));
3955   // Sort the refs for determinism output, the vector returned by FS->refs() has
3956   // been initialized from a DenseSet.
3957   llvm::sort(drop_begin(NameVals, SizeBeforeRefs));
3958 
3959   if (VTableFuncs.empty())
3960     Stream.EmitRecord(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS, NameVals,
3961                       FSModRefsAbbrev);
3962   else {
3963     // VTableFuncs pairs should already be sorted by offset.
3964     for (auto &P : VTableFuncs) {
3965       NameVals.push_back(VE.getValueID(P.FuncVI.getValue()));
3966       NameVals.push_back(P.VTableOffset);
3967     }
3968 
3969     Stream.EmitRecord(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS, NameVals,
3970                       FSModVTableRefsAbbrev);
3971   }
3972   NameVals.clear();
3973 }
3974 
3975 /// Emit the per-module summary section alongside the rest of
3976 /// the module's bitcode.
3977 void ModuleBitcodeWriterBase::writePerModuleGlobalValueSummary() {
3978   // By default we compile with ThinLTO if the module has a summary, but the
3979   // client can request full LTO with a module flag.
3980   bool IsThinLTO = true;
3981   if (auto *MD =
3982           mdconst::extract_or_null<ConstantInt>(M.getModuleFlag("ThinLTO")))
3983     IsThinLTO = MD->getZExtValue();
3984   Stream.EnterSubblock(IsThinLTO ? bitc::GLOBALVAL_SUMMARY_BLOCK_ID
3985                                  : bitc::FULL_LTO_GLOBALVAL_SUMMARY_BLOCK_ID,
3986                        4);
3987 
3988   Stream.EmitRecord(
3989       bitc::FS_VERSION,
3990       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
3991 
3992   // Write the index flags.
3993   uint64_t Flags = 0;
3994   // Bits 1-3 are set only in the combined index, skip them.
3995   if (Index->enableSplitLTOUnit())
3996     Flags |= 0x8;
3997   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Flags});
3998 
3999   if (Index->begin() == Index->end()) {
4000     Stream.ExitBlock();
4001     return;
4002   }
4003 
4004   for (const auto &GVI : valueIds()) {
4005     Stream.EmitRecord(bitc::FS_VALUE_GUID,
4006                       ArrayRef<uint64_t>{GVI.second, GVI.first});
4007   }
4008 
4009   // Abbrev for FS_PERMODULE_PROFILE.
4010   auto Abbv = std::make_shared<BitCodeAbbrev>();
4011   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_PROFILE));
4012   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4013   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4014   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4015   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4016   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4017   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4018   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4019   // numrefs x valueid, n x (valueid, hotness)
4020   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4021   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4022   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4023 
4024   // Abbrev for FS_PERMODULE or FS_PERMODULE_RELBF.
4025   Abbv = std::make_shared<BitCodeAbbrev>();
4026   if (WriteRelBFToSummary)
4027     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_RELBF));
4028   else
4029     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE));
4030   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4031   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4032   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4033   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4034   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4035   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4036   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4037   // numrefs x valueid, n x (valueid [, rel_block_freq])
4038   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4039   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4040   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4041 
4042   // Abbrev for FS_PERMODULE_GLOBALVAR_INIT_REFS.
4043   Abbv = std::make_shared<BitCodeAbbrev>();
4044   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS));
4045   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
4046   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
4047   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));  // valueids
4048   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4049   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4050 
4051   // Abbrev for FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS.
4052   Abbv = std::make_shared<BitCodeAbbrev>();
4053   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS));
4054   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
4055   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
4056   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numrefs
4057   // numrefs x valueid, n x (valueid , offset)
4058   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4059   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4060   unsigned FSModVTableRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4061 
4062   // Abbrev for FS_ALIAS.
4063   Abbv = std::make_shared<BitCodeAbbrev>();
4064   Abbv->Add(BitCodeAbbrevOp(bitc::FS_ALIAS));
4065   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4066   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4067   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4068   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4069 
4070   // Abbrev for FS_TYPE_ID_METADATA
4071   Abbv = std::make_shared<BitCodeAbbrev>();
4072   Abbv->Add(BitCodeAbbrevOp(bitc::FS_TYPE_ID_METADATA));
4073   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid strtab index
4074   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid length
4075   // n x (valueid , offset)
4076   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4077   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4078   unsigned TypeIdCompatibleVtableAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4079 
4080   SmallVector<uint64_t, 64> NameVals;
4081   // Iterate over the list of functions instead of the Index to
4082   // ensure the ordering is stable.
4083   for (const Function &F : M) {
4084     // Summary emission does not support anonymous functions, they have to
4085     // renamed using the anonymous function renaming pass.
4086     if (!F.hasName())
4087       report_fatal_error("Unexpected anonymous function when writing summary");
4088 
4089     ValueInfo VI = Index->getValueInfo(F.getGUID());
4090     if (!VI || VI.getSummaryList().empty()) {
4091       // Only declarations should not have a summary (a declaration might
4092       // however have a summary if the def was in module level asm).
4093       assert(F.isDeclaration());
4094       continue;
4095     }
4096     auto *Summary = VI.getSummaryList()[0].get();
4097     writePerModuleFunctionSummaryRecord(NameVals, Summary, VE.getValueID(&F),
4098                                         FSCallsAbbrev, FSCallsProfileAbbrev, F);
4099   }
4100 
4101   // Capture references from GlobalVariable initializers, which are outside
4102   // of a function scope.
4103   for (const GlobalVariable &G : M.globals())
4104     writeModuleLevelReferences(G, NameVals, FSModRefsAbbrev,
4105                                FSModVTableRefsAbbrev);
4106 
4107   for (const GlobalAlias &A : M.aliases()) {
4108     auto *Aliasee = A.getAliaseeObject();
4109     // Skip ifunc and nameless functions which don't have an entry in the
4110     // summary.
4111     if (!Aliasee->hasName() || isa<GlobalIFunc>(Aliasee))
4112       continue;
4113     auto AliasId = VE.getValueID(&A);
4114     auto AliaseeId = VE.getValueID(Aliasee);
4115     NameVals.push_back(AliasId);
4116     auto *Summary = Index->getGlobalValueSummary(A);
4117     AliasSummary *AS = cast<AliasSummary>(Summary);
4118     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
4119     NameVals.push_back(AliaseeId);
4120     Stream.EmitRecord(bitc::FS_ALIAS, NameVals, FSAliasAbbrev);
4121     NameVals.clear();
4122   }
4123 
4124   for (auto &S : Index->typeIdCompatibleVtableMap()) {
4125     writeTypeIdCompatibleVtableSummaryRecord(NameVals, StrtabBuilder, S.first,
4126                                              S.second, VE);
4127     Stream.EmitRecord(bitc::FS_TYPE_ID_METADATA, NameVals,
4128                       TypeIdCompatibleVtableAbbrev);
4129     NameVals.clear();
4130   }
4131 
4132   Stream.EmitRecord(bitc::FS_BLOCK_COUNT,
4133                     ArrayRef<uint64_t>{Index->getBlockCount()});
4134 
4135   Stream.ExitBlock();
4136 }
4137 
4138 /// Emit the combined summary section into the combined index file.
4139 void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
4140   Stream.EnterSubblock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID, 3);
4141   Stream.EmitRecord(
4142       bitc::FS_VERSION,
4143       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
4144 
4145   // Write the index flags.
4146   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Index.getFlags()});
4147 
4148   for (const auto &GVI : valueIds()) {
4149     Stream.EmitRecord(bitc::FS_VALUE_GUID,
4150                       ArrayRef<uint64_t>{GVI.second, GVI.first});
4151   }
4152 
4153   // Abbrev for FS_COMBINED.
4154   auto Abbv = std::make_shared<BitCodeAbbrev>();
4155   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED));
4156   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4157   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4158   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4159   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4160   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4161   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
4162   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4163   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4164   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4165   // numrefs x valueid, n x (valueid)
4166   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4167   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4168   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4169 
4170   // Abbrev for FS_COMBINED_PROFILE.
4171   Abbv = std::make_shared<BitCodeAbbrev>();
4172   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_PROFILE));
4173   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4174   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4175   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4176   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4177   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4178   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
4179   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4180   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4181   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4182   // numrefs x valueid, n x (valueid, hotness)
4183   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4184   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4185   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4186 
4187   // Abbrev for FS_COMBINED_GLOBALVAR_INIT_REFS.
4188   Abbv = std::make_shared<BitCodeAbbrev>();
4189   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS));
4190   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4191   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4192   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4193   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));    // valueids
4194   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4195   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4196 
4197   // Abbrev for FS_COMBINED_ALIAS.
4198   Abbv = std::make_shared<BitCodeAbbrev>();
4199   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_ALIAS));
4200   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4201   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4202   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4203   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4204   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4205 
4206   // The aliases are emitted as a post-pass, and will point to the value
4207   // id of the aliasee. Save them in a vector for post-processing.
4208   SmallVector<AliasSummary *, 64> Aliases;
4209 
4210   // Save the value id for each summary for alias emission.
4211   DenseMap<const GlobalValueSummary *, unsigned> SummaryToValueIdMap;
4212 
4213   SmallVector<uint64_t, 64> NameVals;
4214 
4215   // Set that will be populated during call to writeFunctionTypeMetadataRecords
4216   // with the type ids referenced by this index file.
4217   std::set<GlobalValue::GUID> ReferencedTypeIds;
4218 
4219   // For local linkage, we also emit the original name separately
4220   // immediately after the record.
4221   auto MaybeEmitOriginalName = [&](GlobalValueSummary &S) {
4222     // We don't need to emit the original name if we are writing the index for
4223     // distributed backends (in which case ModuleToSummariesForIndex is
4224     // non-null). The original name is only needed during the thin link, since
4225     // for SamplePGO the indirect call targets for local functions have
4226     // have the original name annotated in profile.
4227     // Continue to emit it when writing out the entire combined index, which is
4228     // used in testing the thin link via llvm-lto.
4229     if (ModuleToSummariesForIndex || !GlobalValue::isLocalLinkage(S.linkage()))
4230       return;
4231     NameVals.push_back(S.getOriginalName());
4232     Stream.EmitRecord(bitc::FS_COMBINED_ORIGINAL_NAME, NameVals);
4233     NameVals.clear();
4234   };
4235 
4236   std::set<GlobalValue::GUID> DefOrUseGUIDs;
4237   forEachSummary([&](GVInfo I, bool IsAliasee) {
4238     GlobalValueSummary *S = I.second;
4239     assert(S);
4240     DefOrUseGUIDs.insert(I.first);
4241     for (const ValueInfo &VI : S->refs())
4242       DefOrUseGUIDs.insert(VI.getGUID());
4243 
4244     auto ValueId = getValueId(I.first);
4245     assert(ValueId);
4246     SummaryToValueIdMap[S] = *ValueId;
4247 
4248     // If this is invoked for an aliasee, we want to record the above
4249     // mapping, but then not emit a summary entry (if the aliasee is
4250     // to be imported, we will invoke this separately with IsAliasee=false).
4251     if (IsAliasee)
4252       return;
4253 
4254     if (auto *AS = dyn_cast<AliasSummary>(S)) {
4255       // Will process aliases as a post-pass because the reader wants all
4256       // global to be loaded first.
4257       Aliases.push_back(AS);
4258       return;
4259     }
4260 
4261     if (auto *VS = dyn_cast<GlobalVarSummary>(S)) {
4262       NameVals.push_back(*ValueId);
4263       NameVals.push_back(Index.getModuleId(VS->modulePath()));
4264       NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
4265       NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
4266       for (auto &RI : VS->refs()) {
4267         auto RefValueId = getValueId(RI.getGUID());
4268         if (!RefValueId)
4269           continue;
4270         NameVals.push_back(*RefValueId);
4271       }
4272 
4273       // Emit the finished record.
4274       Stream.EmitRecord(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS, NameVals,
4275                         FSModRefsAbbrev);
4276       NameVals.clear();
4277       MaybeEmitOriginalName(*S);
4278       return;
4279     }
4280 
4281     auto GetValueId = [&](const ValueInfo &VI) -> Optional<unsigned> {
4282       return getValueId(VI.getGUID());
4283     };
4284 
4285     auto *FS = cast<FunctionSummary>(S);
4286     writeFunctionTypeMetadataRecords(Stream, FS, GetValueId);
4287     getReferencedTypeIds(FS, ReferencedTypeIds);
4288 
4289     NameVals.push_back(*ValueId);
4290     NameVals.push_back(Index.getModuleId(FS->modulePath()));
4291     NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
4292     NameVals.push_back(FS->instCount());
4293     NameVals.push_back(getEncodedFFlags(FS->fflags()));
4294     NameVals.push_back(FS->entryCount());
4295 
4296     // Fill in below
4297     NameVals.push_back(0); // numrefs
4298     NameVals.push_back(0); // rorefcnt
4299     NameVals.push_back(0); // worefcnt
4300 
4301     unsigned Count = 0, RORefCnt = 0, WORefCnt = 0;
4302     for (auto &RI : FS->refs()) {
4303       auto RefValueId = getValueId(RI.getGUID());
4304       if (!RefValueId)
4305         continue;
4306       NameVals.push_back(*RefValueId);
4307       if (RI.isReadOnly())
4308         RORefCnt++;
4309       else if (RI.isWriteOnly())
4310         WORefCnt++;
4311       Count++;
4312     }
4313     NameVals[6] = Count;
4314     NameVals[7] = RORefCnt;
4315     NameVals[8] = WORefCnt;
4316 
4317     bool HasProfileData = false;
4318     for (auto &EI : FS->calls()) {
4319       HasProfileData |=
4320           EI.second.getHotness() != CalleeInfo::HotnessType::Unknown;
4321       if (HasProfileData)
4322         break;
4323     }
4324 
4325     for (auto &EI : FS->calls()) {
4326       // If this GUID doesn't have a value id, it doesn't have a function
4327       // summary and we don't need to record any calls to it.
4328       Optional<unsigned> CallValueId = GetValueId(EI.first);
4329       if (!CallValueId)
4330         continue;
4331       NameVals.push_back(*CallValueId);
4332       if (HasProfileData)
4333         NameVals.push_back(static_cast<uint8_t>(EI.second.Hotness));
4334     }
4335 
4336     unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
4337     unsigned Code =
4338         (HasProfileData ? bitc::FS_COMBINED_PROFILE : bitc::FS_COMBINED);
4339 
4340     // Emit the finished record.
4341     Stream.EmitRecord(Code, NameVals, FSAbbrev);
4342     NameVals.clear();
4343     MaybeEmitOriginalName(*S);
4344   });
4345 
4346   for (auto *AS : Aliases) {
4347     auto AliasValueId = SummaryToValueIdMap[AS];
4348     assert(AliasValueId);
4349     NameVals.push_back(AliasValueId);
4350     NameVals.push_back(Index.getModuleId(AS->modulePath()));
4351     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
4352     auto AliaseeValueId = SummaryToValueIdMap[&AS->getAliasee()];
4353     assert(AliaseeValueId);
4354     NameVals.push_back(AliaseeValueId);
4355 
4356     // Emit the finished record.
4357     Stream.EmitRecord(bitc::FS_COMBINED_ALIAS, NameVals, FSAliasAbbrev);
4358     NameVals.clear();
4359     MaybeEmitOriginalName(*AS);
4360 
4361     if (auto *FS = dyn_cast<FunctionSummary>(&AS->getAliasee()))
4362       getReferencedTypeIds(FS, ReferencedTypeIds);
4363   }
4364 
4365   if (!Index.cfiFunctionDefs().empty()) {
4366     for (auto &S : Index.cfiFunctionDefs()) {
4367       if (DefOrUseGUIDs.count(
4368               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4369         NameVals.push_back(StrtabBuilder.add(S));
4370         NameVals.push_back(S.size());
4371       }
4372     }
4373     if (!NameVals.empty()) {
4374       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DEFS, NameVals);
4375       NameVals.clear();
4376     }
4377   }
4378 
4379   if (!Index.cfiFunctionDecls().empty()) {
4380     for (auto &S : Index.cfiFunctionDecls()) {
4381       if (DefOrUseGUIDs.count(
4382               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4383         NameVals.push_back(StrtabBuilder.add(S));
4384         NameVals.push_back(S.size());
4385       }
4386     }
4387     if (!NameVals.empty()) {
4388       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DECLS, NameVals);
4389       NameVals.clear();
4390     }
4391   }
4392 
4393   // Walk the GUIDs that were referenced, and write the
4394   // corresponding type id records.
4395   for (auto &T : ReferencedTypeIds) {
4396     auto TidIter = Index.typeIds().equal_range(T);
4397     for (auto It = TidIter.first; It != TidIter.second; ++It) {
4398       writeTypeIdSummaryRecord(NameVals, StrtabBuilder, It->second.first,
4399                                It->second.second);
4400       Stream.EmitRecord(bitc::FS_TYPE_ID, NameVals);
4401       NameVals.clear();
4402     }
4403   }
4404 
4405   Stream.EmitRecord(bitc::FS_BLOCK_COUNT,
4406                     ArrayRef<uint64_t>{Index.getBlockCount()});
4407 
4408   Stream.ExitBlock();
4409 }
4410 
4411 /// Create the "IDENTIFICATION_BLOCK_ID" containing a single string with the
4412 /// current llvm version, and a record for the epoch number.
4413 static void writeIdentificationBlock(BitstreamWriter &Stream) {
4414   Stream.EnterSubblock(bitc::IDENTIFICATION_BLOCK_ID, 5);
4415 
4416   // Write the "user readable" string identifying the bitcode producer
4417   auto Abbv = std::make_shared<BitCodeAbbrev>();
4418   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_STRING));
4419   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4420   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
4421   auto StringAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4422   writeStringRecord(Stream, bitc::IDENTIFICATION_CODE_STRING,
4423                     "LLVM" LLVM_VERSION_STRING, StringAbbrev);
4424 
4425   // Write the epoch version
4426   Abbv = std::make_shared<BitCodeAbbrev>();
4427   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_EPOCH));
4428   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
4429   auto EpochAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4430   constexpr std::array<unsigned, 1> Vals = {{bitc::BITCODE_CURRENT_EPOCH}};
4431   Stream.EmitRecord(bitc::IDENTIFICATION_CODE_EPOCH, Vals, EpochAbbrev);
4432   Stream.ExitBlock();
4433 }
4434 
4435 void ModuleBitcodeWriter::writeModuleHash(size_t BlockStartPos) {
4436   // Emit the module's hash.
4437   // MODULE_CODE_HASH: [5*i32]
4438   if (GenerateHash) {
4439     uint32_t Vals[5];
4440     Hasher.update(ArrayRef<uint8_t>((const uint8_t *)&(Buffer)[BlockStartPos],
4441                                     Buffer.size() - BlockStartPos));
4442     std::array<uint8_t, 20> Hash = Hasher.result();
4443     for (int Pos = 0; Pos < 20; Pos += 4) {
4444       Vals[Pos / 4] = support::endian::read32be(Hash.data() + Pos);
4445     }
4446 
4447     // Emit the finished record.
4448     Stream.EmitRecord(bitc::MODULE_CODE_HASH, Vals);
4449 
4450     if (ModHash)
4451       // Save the written hash value.
4452       llvm::copy(Vals, std::begin(*ModHash));
4453   }
4454 }
4455 
4456 void ModuleBitcodeWriter::write() {
4457   writeIdentificationBlock(Stream);
4458 
4459   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4460   size_t BlockStartPos = Buffer.size();
4461 
4462   writeModuleVersion();
4463 
4464   // Emit blockinfo, which defines the standard abbreviations etc.
4465   writeBlockInfo();
4466 
4467   // Emit information describing all of the types in the module.
4468   writeTypeTable();
4469 
4470   // Emit information about attribute groups.
4471   writeAttributeGroupTable();
4472 
4473   // Emit information about parameter attributes.
4474   writeAttributeTable();
4475 
4476   writeComdats();
4477 
4478   // Emit top-level description of module, including target triple, inline asm,
4479   // descriptors for global variables, and function prototype info.
4480   writeModuleInfo();
4481 
4482   // Emit constants.
4483   writeModuleConstants();
4484 
4485   // Emit metadata kind names.
4486   writeModuleMetadataKinds();
4487 
4488   // Emit metadata.
4489   writeModuleMetadata();
4490 
4491   // Emit module-level use-lists.
4492   if (VE.shouldPreserveUseListOrder())
4493     writeUseListBlock(nullptr);
4494 
4495   writeOperandBundleTags();
4496   writeSyncScopeNames();
4497 
4498   // Emit function bodies.
4499   DenseMap<const Function *, uint64_t> FunctionToBitcodeIndex;
4500   for (const Function &F : M)
4501     if (!F.isDeclaration())
4502       writeFunction(F, FunctionToBitcodeIndex);
4503 
4504   // Need to write after the above call to WriteFunction which populates
4505   // the summary information in the index.
4506   if (Index)
4507     writePerModuleGlobalValueSummary();
4508 
4509   writeGlobalValueSymbolTable(FunctionToBitcodeIndex);
4510 
4511   writeModuleHash(BlockStartPos);
4512 
4513   Stream.ExitBlock();
4514 }
4515 
4516 static void writeInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
4517                                uint32_t &Position) {
4518   support::endian::write32le(&Buffer[Position], Value);
4519   Position += 4;
4520 }
4521 
4522 /// If generating a bc file on darwin, we have to emit a
4523 /// header and trailer to make it compatible with the system archiver.  To do
4524 /// this we emit the following header, and then emit a trailer that pads the
4525 /// file out to be a multiple of 16 bytes.
4526 ///
4527 /// struct bc_header {
4528 ///   uint32_t Magic;         // 0x0B17C0DE
4529 ///   uint32_t Version;       // Version, currently always 0.
4530 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
4531 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
4532 ///   uint32_t CPUType;       // CPU specifier.
4533 ///   ... potentially more later ...
4534 /// };
4535 static void emitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
4536                                          const Triple &TT) {
4537   unsigned CPUType = ~0U;
4538 
4539   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
4540   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
4541   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
4542   // specific constants here because they are implicitly part of the Darwin ABI.
4543   enum {
4544     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
4545     DARWIN_CPU_TYPE_X86        = 7,
4546     DARWIN_CPU_TYPE_ARM        = 12,
4547     DARWIN_CPU_TYPE_POWERPC    = 18
4548   };
4549 
4550   Triple::ArchType Arch = TT.getArch();
4551   if (Arch == Triple::x86_64)
4552     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
4553   else if (Arch == Triple::x86)
4554     CPUType = DARWIN_CPU_TYPE_X86;
4555   else if (Arch == Triple::ppc)
4556     CPUType = DARWIN_CPU_TYPE_POWERPC;
4557   else if (Arch == Triple::ppc64)
4558     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
4559   else if (Arch == Triple::arm || Arch == Triple::thumb)
4560     CPUType = DARWIN_CPU_TYPE_ARM;
4561 
4562   // Traditional Bitcode starts after header.
4563   assert(Buffer.size() >= BWH_HeaderSize &&
4564          "Expected header size to be reserved");
4565   unsigned BCOffset = BWH_HeaderSize;
4566   unsigned BCSize = Buffer.size() - BWH_HeaderSize;
4567 
4568   // Write the magic and version.
4569   unsigned Position = 0;
4570   writeInt32ToBuffer(0x0B17C0DE, Buffer, Position);
4571   writeInt32ToBuffer(0, Buffer, Position); // Version.
4572   writeInt32ToBuffer(BCOffset, Buffer, Position);
4573   writeInt32ToBuffer(BCSize, Buffer, Position);
4574   writeInt32ToBuffer(CPUType, Buffer, Position);
4575 
4576   // If the file is not a multiple of 16 bytes, insert dummy padding.
4577   while (Buffer.size() & 15)
4578     Buffer.push_back(0);
4579 }
4580 
4581 /// Helper to write the header common to all bitcode files.
4582 static void writeBitcodeHeader(BitstreamWriter &Stream) {
4583   // Emit the file header.
4584   Stream.Emit((unsigned)'B', 8);
4585   Stream.Emit((unsigned)'C', 8);
4586   Stream.Emit(0x0, 4);
4587   Stream.Emit(0xC, 4);
4588   Stream.Emit(0xE, 4);
4589   Stream.Emit(0xD, 4);
4590 }
4591 
4592 BitcodeWriter::BitcodeWriter(SmallVectorImpl<char> &Buffer, raw_fd_stream *FS)
4593     : Buffer(Buffer), Stream(new BitstreamWriter(Buffer, FS, FlushThreshold)) {
4594   writeBitcodeHeader(*Stream);
4595 }
4596 
4597 BitcodeWriter::~BitcodeWriter() { assert(WroteStrtab); }
4598 
4599 void BitcodeWriter::writeBlob(unsigned Block, unsigned Record, StringRef Blob) {
4600   Stream->EnterSubblock(Block, 3);
4601 
4602   auto Abbv = std::make_shared<BitCodeAbbrev>();
4603   Abbv->Add(BitCodeAbbrevOp(Record));
4604   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
4605   auto AbbrevNo = Stream->EmitAbbrev(std::move(Abbv));
4606 
4607   Stream->EmitRecordWithBlob(AbbrevNo, ArrayRef<uint64_t>{Record}, Blob);
4608 
4609   Stream->ExitBlock();
4610 }
4611 
4612 void BitcodeWriter::writeSymtab() {
4613   assert(!WroteStrtab && !WroteSymtab);
4614 
4615   // If any module has module-level inline asm, we will require a registered asm
4616   // parser for the target so that we can create an accurate symbol table for
4617   // the module.
4618   for (Module *M : Mods) {
4619     if (M->getModuleInlineAsm().empty())
4620       continue;
4621 
4622     std::string Err;
4623     const Triple TT(M->getTargetTriple());
4624     const Target *T = TargetRegistry::lookupTarget(TT.str(), Err);
4625     if (!T || !T->hasMCAsmParser())
4626       return;
4627   }
4628 
4629   WroteSymtab = true;
4630   SmallVector<char, 0> Symtab;
4631   // The irsymtab::build function may be unable to create a symbol table if the
4632   // module is malformed (e.g. it contains an invalid alias). Writing a symbol
4633   // table is not required for correctness, but we still want to be able to
4634   // write malformed modules to bitcode files, so swallow the error.
4635   if (Error E = irsymtab::build(Mods, Symtab, StrtabBuilder, Alloc)) {
4636     consumeError(std::move(E));
4637     return;
4638   }
4639 
4640   writeBlob(bitc::SYMTAB_BLOCK_ID, bitc::SYMTAB_BLOB,
4641             {Symtab.data(), Symtab.size()});
4642 }
4643 
4644 void BitcodeWriter::writeStrtab() {
4645   assert(!WroteStrtab);
4646 
4647   std::vector<char> Strtab;
4648   StrtabBuilder.finalizeInOrder();
4649   Strtab.resize(StrtabBuilder.getSize());
4650   StrtabBuilder.write((uint8_t *)Strtab.data());
4651 
4652   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB,
4653             {Strtab.data(), Strtab.size()});
4654 
4655   WroteStrtab = true;
4656 }
4657 
4658 void BitcodeWriter::copyStrtab(StringRef Strtab) {
4659   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB, Strtab);
4660   WroteStrtab = true;
4661 }
4662 
4663 void BitcodeWriter::writeModule(const Module &M,
4664                                 bool ShouldPreserveUseListOrder,
4665                                 const ModuleSummaryIndex *Index,
4666                                 bool GenerateHash, ModuleHash *ModHash) {
4667   assert(!WroteStrtab);
4668 
4669   // The Mods vector is used by irsymtab::build, which requires non-const
4670   // Modules in case it needs to materialize metadata. But the bitcode writer
4671   // requires that the module is materialized, so we can cast to non-const here,
4672   // after checking that it is in fact materialized.
4673   assert(M.isMaterialized());
4674   Mods.push_back(const_cast<Module *>(&M));
4675 
4676   ModuleBitcodeWriter ModuleWriter(M, Buffer, StrtabBuilder, *Stream,
4677                                    ShouldPreserveUseListOrder, Index,
4678                                    GenerateHash, ModHash);
4679   ModuleWriter.write();
4680 }
4681 
4682 void BitcodeWriter::writeIndex(
4683     const ModuleSummaryIndex *Index,
4684     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4685   IndexBitcodeWriter IndexWriter(*Stream, StrtabBuilder, *Index,
4686                                  ModuleToSummariesForIndex);
4687   IndexWriter.write();
4688 }
4689 
4690 /// Write the specified module to the specified output stream.
4691 void llvm::WriteBitcodeToFile(const Module &M, raw_ostream &Out,
4692                               bool ShouldPreserveUseListOrder,
4693                               const ModuleSummaryIndex *Index,
4694                               bool GenerateHash, ModuleHash *ModHash) {
4695   SmallVector<char, 0> Buffer;
4696   Buffer.reserve(256*1024);
4697 
4698   // If this is darwin or another generic macho target, reserve space for the
4699   // header.
4700   Triple TT(M.getTargetTriple());
4701   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4702     Buffer.insert(Buffer.begin(), BWH_HeaderSize, 0);
4703 
4704   BitcodeWriter Writer(Buffer, dyn_cast<raw_fd_stream>(&Out));
4705   Writer.writeModule(M, ShouldPreserveUseListOrder, Index, GenerateHash,
4706                      ModHash);
4707   Writer.writeSymtab();
4708   Writer.writeStrtab();
4709 
4710   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4711     emitDarwinBCHeaderAndTrailer(Buffer, TT);
4712 
4713   // Write the generated bitstream to "Out".
4714   if (!Buffer.empty())
4715     Out.write((char *)&Buffer.front(), Buffer.size());
4716 }
4717 
4718 void IndexBitcodeWriter::write() {
4719   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4720 
4721   writeModuleVersion();
4722 
4723   // Write the module paths in the combined index.
4724   writeModStrings();
4725 
4726   // Write the summary combined index records.
4727   writeCombinedGlobalValueSummary();
4728 
4729   Stream.ExitBlock();
4730 }
4731 
4732 // Write the specified module summary index to the given raw output stream,
4733 // where it will be written in a new bitcode block. This is used when
4734 // writing the combined index file for ThinLTO. When writing a subset of the
4735 // index for a distributed backend, provide a \p ModuleToSummariesForIndex map.
4736 void llvm::writeIndexToFile(
4737     const ModuleSummaryIndex &Index, raw_ostream &Out,
4738     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4739   SmallVector<char, 0> Buffer;
4740   Buffer.reserve(256 * 1024);
4741 
4742   BitcodeWriter Writer(Buffer);
4743   Writer.writeIndex(&Index, ModuleToSummariesForIndex);
4744   Writer.writeStrtab();
4745 
4746   Out.write((char *)&Buffer.front(), Buffer.size());
4747 }
4748 
4749 namespace {
4750 
4751 /// Class to manage the bitcode writing for a thin link bitcode file.
4752 class ThinLinkBitcodeWriter : public ModuleBitcodeWriterBase {
4753   /// ModHash is for use in ThinLTO incremental build, generated while writing
4754   /// the module bitcode file.
4755   const ModuleHash *ModHash;
4756 
4757 public:
4758   ThinLinkBitcodeWriter(const Module &M, StringTableBuilder &StrtabBuilder,
4759                         BitstreamWriter &Stream,
4760                         const ModuleSummaryIndex &Index,
4761                         const ModuleHash &ModHash)
4762       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
4763                                 /*ShouldPreserveUseListOrder=*/false, &Index),
4764         ModHash(&ModHash) {}
4765 
4766   void write();
4767 
4768 private:
4769   void writeSimplifiedModuleInfo();
4770 };
4771 
4772 } // end anonymous namespace
4773 
4774 // This function writes a simpilified module info for thin link bitcode file.
4775 // It only contains the source file name along with the name(the offset and
4776 // size in strtab) and linkage for global values. For the global value info
4777 // entry, in order to keep linkage at offset 5, there are three zeros used
4778 // as padding.
4779 void ThinLinkBitcodeWriter::writeSimplifiedModuleInfo() {
4780   SmallVector<unsigned, 64> Vals;
4781   // Emit the module's source file name.
4782   {
4783     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
4784     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
4785     if (Bits == SE_Char6)
4786       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
4787     else if (Bits == SE_Fixed7)
4788       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
4789 
4790     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
4791     auto Abbv = std::make_shared<BitCodeAbbrev>();
4792     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
4793     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4794     Abbv->Add(AbbrevOpToUse);
4795     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4796 
4797     for (const auto P : M.getSourceFileName())
4798       Vals.push_back((unsigned char)P);
4799 
4800     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
4801     Vals.clear();
4802   }
4803 
4804   // Emit the global variable information.
4805   for (const GlobalVariable &GV : M.globals()) {
4806     // GLOBALVAR: [strtab offset, strtab size, 0, 0, 0, linkage]
4807     Vals.push_back(StrtabBuilder.add(GV.getName()));
4808     Vals.push_back(GV.getName().size());
4809     Vals.push_back(0);
4810     Vals.push_back(0);
4811     Vals.push_back(0);
4812     Vals.push_back(getEncodedLinkage(GV));
4813 
4814     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals);
4815     Vals.clear();
4816   }
4817 
4818   // Emit the function proto information.
4819   for (const Function &F : M) {
4820     // FUNCTION:  [strtab offset, strtab size, 0, 0, 0, linkage]
4821     Vals.push_back(StrtabBuilder.add(F.getName()));
4822     Vals.push_back(F.getName().size());
4823     Vals.push_back(0);
4824     Vals.push_back(0);
4825     Vals.push_back(0);
4826     Vals.push_back(getEncodedLinkage(F));
4827 
4828     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals);
4829     Vals.clear();
4830   }
4831 
4832   // Emit the alias information.
4833   for (const GlobalAlias &A : M.aliases()) {
4834     // ALIAS: [strtab offset, strtab size, 0, 0, 0, linkage]
4835     Vals.push_back(StrtabBuilder.add(A.getName()));
4836     Vals.push_back(A.getName().size());
4837     Vals.push_back(0);
4838     Vals.push_back(0);
4839     Vals.push_back(0);
4840     Vals.push_back(getEncodedLinkage(A));
4841 
4842     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals);
4843     Vals.clear();
4844   }
4845 
4846   // Emit the ifunc information.
4847   for (const GlobalIFunc &I : M.ifuncs()) {
4848     // IFUNC: [strtab offset, strtab size, 0, 0, 0, linkage]
4849     Vals.push_back(StrtabBuilder.add(I.getName()));
4850     Vals.push_back(I.getName().size());
4851     Vals.push_back(0);
4852     Vals.push_back(0);
4853     Vals.push_back(0);
4854     Vals.push_back(getEncodedLinkage(I));
4855 
4856     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
4857     Vals.clear();
4858   }
4859 }
4860 
4861 void ThinLinkBitcodeWriter::write() {
4862   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4863 
4864   writeModuleVersion();
4865 
4866   writeSimplifiedModuleInfo();
4867 
4868   writePerModuleGlobalValueSummary();
4869 
4870   // Write module hash.
4871   Stream.EmitRecord(bitc::MODULE_CODE_HASH, ArrayRef<uint32_t>(*ModHash));
4872 
4873   Stream.ExitBlock();
4874 }
4875 
4876 void BitcodeWriter::writeThinLinkBitcode(const Module &M,
4877                                          const ModuleSummaryIndex &Index,
4878                                          const ModuleHash &ModHash) {
4879   assert(!WroteStrtab);
4880 
4881   // The Mods vector is used by irsymtab::build, which requires non-const
4882   // Modules in case it needs to materialize metadata. But the bitcode writer
4883   // requires that the module is materialized, so we can cast to non-const here,
4884   // after checking that it is in fact materialized.
4885   assert(M.isMaterialized());
4886   Mods.push_back(const_cast<Module *>(&M));
4887 
4888   ThinLinkBitcodeWriter ThinLinkWriter(M, StrtabBuilder, *Stream, Index,
4889                                        ModHash);
4890   ThinLinkWriter.write();
4891 }
4892 
4893 // Write the specified thin link bitcode file to the given raw output stream,
4894 // where it will be written in a new bitcode block. This is used when
4895 // writing the per-module index file for ThinLTO.
4896 void llvm::writeThinLinkBitcodeToFile(const Module &M, raw_ostream &Out,
4897                                       const ModuleSummaryIndex &Index,
4898                                       const ModuleHash &ModHash) {
4899   SmallVector<char, 0> Buffer;
4900   Buffer.reserve(256 * 1024);
4901 
4902   BitcodeWriter Writer(Buffer);
4903   Writer.writeThinLinkBitcode(M, Index, ModHash);
4904   Writer.writeSymtab();
4905   Writer.writeStrtab();
4906 
4907   Out.write((char *)&Buffer.front(), Buffer.size());
4908 }
4909 
4910 static const char *getSectionNameForBitcode(const Triple &T) {
4911   switch (T.getObjectFormat()) {
4912   case Triple::MachO:
4913     return "__LLVM,__bitcode";
4914   case Triple::COFF:
4915   case Triple::ELF:
4916   case Triple::Wasm:
4917   case Triple::UnknownObjectFormat:
4918     return ".llvmbc";
4919   case Triple::GOFF:
4920     llvm_unreachable("GOFF is not yet implemented");
4921     break;
4922   case Triple::SPIRV:
4923     llvm_unreachable("SPIRV is not yet implemented");
4924     break;
4925   case Triple::XCOFF:
4926     llvm_unreachable("XCOFF is not yet implemented");
4927     break;
4928   case Triple::DXContainer:
4929     llvm_unreachable("DXContainer is not yet implemented");
4930     break;
4931   }
4932   llvm_unreachable("Unimplemented ObjectFormatType");
4933 }
4934 
4935 static const char *getSectionNameForCommandline(const Triple &T) {
4936   switch (T.getObjectFormat()) {
4937   case Triple::MachO:
4938     return "__LLVM,__cmdline";
4939   case Triple::COFF:
4940   case Triple::ELF:
4941   case Triple::Wasm:
4942   case Triple::UnknownObjectFormat:
4943     return ".llvmcmd";
4944   case Triple::GOFF:
4945     llvm_unreachable("GOFF is not yet implemented");
4946     break;
4947   case Triple::SPIRV:
4948     llvm_unreachable("SPIRV is not yet implemented");
4949     break;
4950   case Triple::XCOFF:
4951     llvm_unreachable("XCOFF is not yet implemented");
4952     break;
4953   case Triple::DXContainer:
4954     llvm_unreachable("DXC is not yet implemented");
4955     break;
4956   }
4957   llvm_unreachable("Unimplemented ObjectFormatType");
4958 }
4959 
4960 void llvm::embedBitcodeInModule(llvm::Module &M, llvm::MemoryBufferRef Buf,
4961                                 bool EmbedBitcode, bool EmbedCmdline,
4962                                 const std::vector<uint8_t> &CmdArgs) {
4963   // Save llvm.compiler.used and remove it.
4964   SmallVector<Constant *, 2> UsedArray;
4965   SmallVector<GlobalValue *, 4> UsedGlobals;
4966   Type *UsedElementType = Type::getInt8Ty(M.getContext())->getPointerTo(0);
4967   GlobalVariable *Used = collectUsedGlobalVariables(M, UsedGlobals, true);
4968   for (auto *GV : UsedGlobals) {
4969     if (GV->getName() != "llvm.embedded.module" &&
4970         GV->getName() != "llvm.cmdline")
4971       UsedArray.push_back(
4972           ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
4973   }
4974   if (Used)
4975     Used->eraseFromParent();
4976 
4977   // Embed the bitcode for the llvm module.
4978   std::string Data;
4979   ArrayRef<uint8_t> ModuleData;
4980   Triple T(M.getTargetTriple());
4981 
4982   if (EmbedBitcode) {
4983     if (Buf.getBufferSize() == 0 ||
4984         !isBitcode((const unsigned char *)Buf.getBufferStart(),
4985                    (const unsigned char *)Buf.getBufferEnd())) {
4986       // If the input is LLVM Assembly, bitcode is produced by serializing
4987       // the module. Use-lists order need to be preserved in this case.
4988       llvm::raw_string_ostream OS(Data);
4989       llvm::WriteBitcodeToFile(M, OS, /* ShouldPreserveUseListOrder */ true);
4990       ModuleData =
4991           ArrayRef<uint8_t>((const uint8_t *)OS.str().data(), OS.str().size());
4992     } else
4993       // If the input is LLVM bitcode, write the input byte stream directly.
4994       ModuleData = ArrayRef<uint8_t>((const uint8_t *)Buf.getBufferStart(),
4995                                      Buf.getBufferSize());
4996   }
4997   llvm::Constant *ModuleConstant =
4998       llvm::ConstantDataArray::get(M.getContext(), ModuleData);
4999   llvm::GlobalVariable *GV = new llvm::GlobalVariable(
5000       M, ModuleConstant->getType(), true, llvm::GlobalValue::PrivateLinkage,
5001       ModuleConstant);
5002   GV->setSection(getSectionNameForBitcode(T));
5003   // Set alignment to 1 to prevent padding between two contributions from input
5004   // sections after linking.
5005   GV->setAlignment(Align(1));
5006   UsedArray.push_back(
5007       ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
5008   if (llvm::GlobalVariable *Old =
5009           M.getGlobalVariable("llvm.embedded.module", true)) {
5010     assert(Old->hasZeroLiveUses() &&
5011            "llvm.embedded.module can only be used once in llvm.compiler.used");
5012     GV->takeName(Old);
5013     Old->eraseFromParent();
5014   } else {
5015     GV->setName("llvm.embedded.module");
5016   }
5017 
5018   // Skip if only bitcode needs to be embedded.
5019   if (EmbedCmdline) {
5020     // Embed command-line options.
5021     ArrayRef<uint8_t> CmdData(const_cast<uint8_t *>(CmdArgs.data()),
5022                               CmdArgs.size());
5023     llvm::Constant *CmdConstant =
5024         llvm::ConstantDataArray::get(M.getContext(), CmdData);
5025     GV = new llvm::GlobalVariable(M, CmdConstant->getType(), true,
5026                                   llvm::GlobalValue::PrivateLinkage,
5027                                   CmdConstant);
5028     GV->setSection(getSectionNameForCommandline(T));
5029     GV->setAlignment(Align(1));
5030     UsedArray.push_back(
5031         ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
5032     if (llvm::GlobalVariable *Old = M.getGlobalVariable("llvm.cmdline", true)) {
5033       assert(Old->hasZeroLiveUses() &&
5034              "llvm.cmdline can only be used once in llvm.compiler.used");
5035       GV->takeName(Old);
5036       Old->eraseFromParent();
5037     } else {
5038       GV->setName("llvm.cmdline");
5039     }
5040   }
5041 
5042   if (UsedArray.empty())
5043     return;
5044 
5045   // Recreate llvm.compiler.used.
5046   ArrayType *ATy = ArrayType::get(UsedElementType, UsedArray.size());
5047   auto *NewUsed = new GlobalVariable(
5048       M, ATy, false, llvm::GlobalValue::AppendingLinkage,
5049       llvm::ConstantArray::get(ATy, UsedArray), "llvm.compiler.used");
5050   NewUsed->setSection("llvm.metadata");
5051 }
5052