xref: /llvm-project/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp (revision 5da674492a5acf8e08a58f611e39ff4cd6a16dfe)
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/STLExtras.h"
20 #include "llvm/ADT/SetVector.h"
21 #include "llvm/ADT/SmallPtrSet.h"
22 #include "llvm/ADT/SmallString.h"
23 #include "llvm/ADT/SmallVector.h"
24 #include "llvm/ADT/StringMap.h"
25 #include "llvm/ADT/StringRef.h"
26 #include "llvm/Bitcode/BitcodeCommon.h"
27 #include "llvm/Bitcode/BitcodeReader.h"
28 #include "llvm/Bitcode/LLVMBitCodes.h"
29 #include "llvm/Bitstream/BitCodes.h"
30 #include "llvm/Bitstream/BitstreamWriter.h"
31 #include "llvm/Config/llvm-config.h"
32 #include "llvm/IR/Attributes.h"
33 #include "llvm/IR/BasicBlock.h"
34 #include "llvm/IR/Comdat.h"
35 #include "llvm/IR/Constant.h"
36 #include "llvm/IR/Constants.h"
37 #include "llvm/IR/DebugInfoMetadata.h"
38 #include "llvm/IR/DebugLoc.h"
39 #include "llvm/IR/DerivedTypes.h"
40 #include "llvm/IR/Function.h"
41 #include "llvm/IR/GlobalAlias.h"
42 #include "llvm/IR/GlobalIFunc.h"
43 #include "llvm/IR/GlobalObject.h"
44 #include "llvm/IR/GlobalValue.h"
45 #include "llvm/IR/GlobalVariable.h"
46 #include "llvm/IR/InlineAsm.h"
47 #include "llvm/IR/InstrTypes.h"
48 #include "llvm/IR/Instruction.h"
49 #include "llvm/IR/Instructions.h"
50 #include "llvm/IR/LLVMContext.h"
51 #include "llvm/IR/Metadata.h"
52 #include "llvm/IR/Module.h"
53 #include "llvm/IR/ModuleSummaryIndex.h"
54 #include "llvm/IR/Operator.h"
55 #include "llvm/IR/Type.h"
56 #include "llvm/IR/UseListOrder.h"
57 #include "llvm/IR/Value.h"
58 #include "llvm/IR/ValueSymbolTable.h"
59 #include "llvm/MC/StringTableBuilder.h"
60 #include "llvm/MC/TargetRegistry.h"
61 #include "llvm/Object/IRSymtab.h"
62 #include "llvm/Support/AtomicOrdering.h"
63 #include "llvm/Support/Casting.h"
64 #include "llvm/Support/CommandLine.h"
65 #include "llvm/Support/Endian.h"
66 #include "llvm/Support/Error.h"
67 #include "llvm/Support/ErrorHandling.h"
68 #include "llvm/Support/MathExtras.h"
69 #include "llvm/Support/SHA1.h"
70 #include "llvm/Support/raw_ostream.h"
71 #include "llvm/TargetParser/Triple.h"
72 #include <algorithm>
73 #include <cassert>
74 #include <cstddef>
75 #include <cstdint>
76 #include <iterator>
77 #include <map>
78 #include <memory>
79 #include <optional>
80 #include <string>
81 #include <utility>
82 #include <vector>
83 
84 using namespace llvm;
85 
86 static cl::opt<unsigned>
87     IndexThreshold("bitcode-mdindex-threshold", cl::Hidden, cl::init(25),
88                    cl::desc("Number of metadatas above which we emit an index "
89                             "to enable lazy-loading"));
90 static cl::opt<uint32_t> FlushThreshold(
91     "bitcode-flush-threshold", cl::Hidden, cl::init(512),
92     cl::desc("The threshold (unit M) for flushing LLVM bitcode."));
93 
94 static cl::opt<bool> WriteRelBFToSummary(
95     "write-relbf-to-summary", cl::Hidden, cl::init(false),
96     cl::desc("Write relative block frequency to function summary "));
97 
98 namespace llvm {
99 extern FunctionSummary::ForceSummaryHotnessType ForceSummaryEdgesCold;
100 }
101 
102 namespace {
103 
104 /// These are manifest constants used by the bitcode writer. They do not need to
105 /// be kept in sync with the reader, but need to be consistent within this file.
106 enum {
107   // VALUE_SYMTAB_BLOCK abbrev id's.
108   VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
109   VST_ENTRY_7_ABBREV,
110   VST_ENTRY_6_ABBREV,
111   VST_BBENTRY_6_ABBREV,
112 
113   // CONSTANTS_BLOCK abbrev id's.
114   CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
115   CONSTANTS_INTEGER_ABBREV,
116   CONSTANTS_CE_CAST_Abbrev,
117   CONSTANTS_NULL_Abbrev,
118 
119   // FUNCTION_BLOCK abbrev id's.
120   FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
121   FUNCTION_INST_UNOP_ABBREV,
122   FUNCTION_INST_UNOP_FLAGS_ABBREV,
123   FUNCTION_INST_BINOP_ABBREV,
124   FUNCTION_INST_BINOP_FLAGS_ABBREV,
125   FUNCTION_INST_CAST_ABBREV,
126   FUNCTION_INST_RET_VOID_ABBREV,
127   FUNCTION_INST_RET_VAL_ABBREV,
128   FUNCTION_INST_UNREACHABLE_ABBREV,
129   FUNCTION_INST_GEP_ABBREV,
130 };
131 
132 /// Abstract class to manage the bitcode writing, subclassed for each bitcode
133 /// file type.
134 class BitcodeWriterBase {
135 protected:
136   /// The stream created and owned by the client.
137   BitstreamWriter &Stream;
138 
139   StringTableBuilder &StrtabBuilder;
140 
141 public:
142   /// Constructs a BitcodeWriterBase object that writes to the provided
143   /// \p Stream.
144   BitcodeWriterBase(BitstreamWriter &Stream, StringTableBuilder &StrtabBuilder)
145       : Stream(Stream), StrtabBuilder(StrtabBuilder) {}
146 
147 protected:
148   void writeModuleVersion();
149 };
150 
151 void BitcodeWriterBase::writeModuleVersion() {
152   // VERSION: [version#]
153   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, ArrayRef<uint64_t>{2});
154 }
155 
156 /// Base class to manage the module bitcode writing, currently subclassed for
157 /// ModuleBitcodeWriter and ThinLinkBitcodeWriter.
158 class ModuleBitcodeWriterBase : public BitcodeWriterBase {
159 protected:
160   /// The Module to write to bitcode.
161   const Module &M;
162 
163   /// Enumerates ids for all values in the module.
164   ValueEnumerator VE;
165 
166   /// Optional per-module index to write for ThinLTO.
167   const ModuleSummaryIndex *Index;
168 
169   /// Map that holds the correspondence between GUIDs in the summary index,
170   /// that came from indirect call profiles, and a value id generated by this
171   /// class to use in the VST and summary block records.
172   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
173 
174   /// Tracks the last value id recorded in the GUIDToValueMap.
175   unsigned GlobalValueId;
176 
177   /// Saves the offset of the VSTOffset record that must eventually be
178   /// backpatched with the offset of the actual VST.
179   uint64_t VSTOffsetPlaceholder = 0;
180 
181 public:
182   /// Constructs a ModuleBitcodeWriterBase object for the given Module,
183   /// writing to the provided \p Buffer.
184   ModuleBitcodeWriterBase(const Module &M, StringTableBuilder &StrtabBuilder,
185                           BitstreamWriter &Stream,
186                           bool ShouldPreserveUseListOrder,
187                           const ModuleSummaryIndex *Index)
188       : BitcodeWriterBase(Stream, StrtabBuilder), M(M),
189         VE(M, ShouldPreserveUseListOrder), Index(Index) {
190     // Assign ValueIds to any callee values in the index that came from
191     // indirect call profiles and were recorded as a GUID not a Value*
192     // (which would have been assigned an ID by the ValueEnumerator).
193     // The starting ValueId is just after the number of values in the
194     // ValueEnumerator, so that they can be emitted in the VST.
195     GlobalValueId = VE.getValues().size();
196     if (!Index)
197       return;
198     for (const auto &GUIDSummaryLists : *Index)
199       // Examine all summaries for this GUID.
200       for (auto &Summary : GUIDSummaryLists.second.SummaryList)
201         if (auto FS = dyn_cast<FunctionSummary>(Summary.get()))
202           // For each call in the function summary, see if the call
203           // is to a GUID (which means it is for an indirect call,
204           // otherwise we would have a Value for it). If so, synthesize
205           // a value id.
206           for (auto &CallEdge : FS->calls())
207             if (!CallEdge.first.haveGVs() || !CallEdge.first.getValue())
208               assignValueId(CallEdge.first.getGUID());
209   }
210 
211 protected:
212   void writePerModuleGlobalValueSummary();
213 
214 private:
215   void writePerModuleFunctionSummaryRecord(
216       SmallVector<uint64_t, 64> &NameVals, GlobalValueSummary *Summary,
217       unsigned ValueID, unsigned FSCallsAbbrev, unsigned FSCallsProfileAbbrev,
218       unsigned CallsiteAbbrev, unsigned AllocAbbrev, const Function &F);
219   void writeModuleLevelReferences(const GlobalVariable &V,
220                                   SmallVector<uint64_t, 64> &NameVals,
221                                   unsigned FSModRefsAbbrev,
222                                   unsigned FSModVTableRefsAbbrev);
223 
224   void assignValueId(GlobalValue::GUID ValGUID) {
225     GUIDToValueIdMap[ValGUID] = ++GlobalValueId;
226   }
227 
228   unsigned getValueId(GlobalValue::GUID ValGUID) {
229     const auto &VMI = GUIDToValueIdMap.find(ValGUID);
230     // Expect that any GUID value had a value Id assigned by an
231     // earlier call to assignValueId.
232     assert(VMI != GUIDToValueIdMap.end() &&
233            "GUID does not have assigned value Id");
234     return VMI->second;
235   }
236 
237   // Helper to get the valueId for the type of value recorded in VI.
238   unsigned getValueId(ValueInfo VI) {
239     if (!VI.haveGVs() || !VI.getValue())
240       return getValueId(VI.getGUID());
241     return VE.getValueID(VI.getValue());
242   }
243 
244   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
245 };
246 
247 /// Class to manage the bitcode writing for a module.
248 class ModuleBitcodeWriter : public ModuleBitcodeWriterBase {
249   /// Pointer to the buffer allocated by caller for bitcode writing.
250   const SmallVectorImpl<char> &Buffer;
251 
252   /// True if a module hash record should be written.
253   bool GenerateHash;
254 
255   /// If non-null, when GenerateHash is true, the resulting hash is written
256   /// into ModHash.
257   ModuleHash *ModHash;
258 
259   SHA1 Hasher;
260 
261   /// The start bit of the identification block.
262   uint64_t BitcodeStartBit;
263 
264 public:
265   /// Constructs a ModuleBitcodeWriter object for the given Module,
266   /// writing to the provided \p Buffer.
267   ModuleBitcodeWriter(const Module &M, SmallVectorImpl<char> &Buffer,
268                       StringTableBuilder &StrtabBuilder,
269                       BitstreamWriter &Stream, bool ShouldPreserveUseListOrder,
270                       const ModuleSummaryIndex *Index, bool GenerateHash,
271                       ModuleHash *ModHash = nullptr)
272       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
273                                 ShouldPreserveUseListOrder, Index),
274         Buffer(Buffer), GenerateHash(GenerateHash), ModHash(ModHash),
275         BitcodeStartBit(Stream.GetCurrentBitNo()) {}
276 
277   /// Emit the current module to the bitstream.
278   void write();
279 
280 private:
281   uint64_t bitcodeStartBit() { return BitcodeStartBit; }
282 
283   size_t addToStrtab(StringRef Str);
284 
285   void writeAttributeGroupTable();
286   void writeAttributeTable();
287   void writeTypeTable();
288   void writeComdats();
289   void writeValueSymbolTableForwardDecl();
290   void writeModuleInfo();
291   void writeValueAsMetadata(const ValueAsMetadata *MD,
292                             SmallVectorImpl<uint64_t> &Record);
293   void writeMDTuple(const MDTuple *N, SmallVectorImpl<uint64_t> &Record,
294                     unsigned Abbrev);
295   unsigned createDILocationAbbrev();
296   void writeDILocation(const DILocation *N, SmallVectorImpl<uint64_t> &Record,
297                        unsigned &Abbrev);
298   unsigned createGenericDINodeAbbrev();
299   void writeGenericDINode(const GenericDINode *N,
300                           SmallVectorImpl<uint64_t> &Record, unsigned &Abbrev);
301   void writeDISubrange(const DISubrange *N, SmallVectorImpl<uint64_t> &Record,
302                        unsigned Abbrev);
303   void writeDIGenericSubrange(const DIGenericSubrange *N,
304                               SmallVectorImpl<uint64_t> &Record,
305                               unsigned Abbrev);
306   void writeDIEnumerator(const DIEnumerator *N,
307                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
308   void writeDIBasicType(const DIBasicType *N, SmallVectorImpl<uint64_t> &Record,
309                         unsigned Abbrev);
310   void writeDIStringType(const DIStringType *N,
311                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
312   void writeDIDerivedType(const DIDerivedType *N,
313                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
314   void writeDICompositeType(const DICompositeType *N,
315                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
316   void writeDISubroutineType(const DISubroutineType *N,
317                              SmallVectorImpl<uint64_t> &Record,
318                              unsigned Abbrev);
319   void writeDIFile(const DIFile *N, SmallVectorImpl<uint64_t> &Record,
320                    unsigned Abbrev);
321   void writeDICompileUnit(const DICompileUnit *N,
322                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
323   void writeDISubprogram(const DISubprogram *N,
324                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
325   void writeDILexicalBlock(const DILexicalBlock *N,
326                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
327   void writeDILexicalBlockFile(const DILexicalBlockFile *N,
328                                SmallVectorImpl<uint64_t> &Record,
329                                unsigned Abbrev);
330   void writeDICommonBlock(const DICommonBlock *N,
331                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
332   void writeDINamespace(const DINamespace *N, SmallVectorImpl<uint64_t> &Record,
333                         unsigned Abbrev);
334   void writeDIMacro(const DIMacro *N, SmallVectorImpl<uint64_t> &Record,
335                     unsigned Abbrev);
336   void writeDIMacroFile(const DIMacroFile *N, SmallVectorImpl<uint64_t> &Record,
337                         unsigned Abbrev);
338   void writeDIArgList(const DIArgList *N, SmallVectorImpl<uint64_t> &Record,
339                       unsigned Abbrev);
340   void writeDIModule(const DIModule *N, SmallVectorImpl<uint64_t> &Record,
341                      unsigned Abbrev);
342   void writeDIAssignID(const DIAssignID *N, SmallVectorImpl<uint64_t> &Record,
343                        unsigned Abbrev);
344   void writeDITemplateTypeParameter(const DITemplateTypeParameter *N,
345                                     SmallVectorImpl<uint64_t> &Record,
346                                     unsigned Abbrev);
347   void writeDITemplateValueParameter(const DITemplateValueParameter *N,
348                                      SmallVectorImpl<uint64_t> &Record,
349                                      unsigned Abbrev);
350   void writeDIGlobalVariable(const DIGlobalVariable *N,
351                              SmallVectorImpl<uint64_t> &Record,
352                              unsigned Abbrev);
353   void writeDILocalVariable(const DILocalVariable *N,
354                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
355   void writeDILabel(const DILabel *N,
356                     SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
357   void writeDIExpression(const DIExpression *N,
358                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
359   void writeDIGlobalVariableExpression(const DIGlobalVariableExpression *N,
360                                        SmallVectorImpl<uint64_t> &Record,
361                                        unsigned Abbrev);
362   void writeDIObjCProperty(const DIObjCProperty *N,
363                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
364   void writeDIImportedEntity(const DIImportedEntity *N,
365                              SmallVectorImpl<uint64_t> &Record,
366                              unsigned Abbrev);
367   unsigned createNamedMetadataAbbrev();
368   void writeNamedMetadata(SmallVectorImpl<uint64_t> &Record);
369   unsigned createMetadataStringsAbbrev();
370   void writeMetadataStrings(ArrayRef<const Metadata *> Strings,
371                             SmallVectorImpl<uint64_t> &Record);
372   void writeMetadataRecords(ArrayRef<const Metadata *> MDs,
373                             SmallVectorImpl<uint64_t> &Record,
374                             std::vector<unsigned> *MDAbbrevs = nullptr,
375                             std::vector<uint64_t> *IndexPos = nullptr);
376   void writeModuleMetadata();
377   void writeFunctionMetadata(const Function &F);
378   void writeFunctionMetadataAttachment(const Function &F);
379   void pushGlobalMetadataAttachment(SmallVectorImpl<uint64_t> &Record,
380                                     const GlobalObject &GO);
381   void writeModuleMetadataKinds();
382   void writeOperandBundleTags();
383   void writeSyncScopeNames();
384   void writeConstants(unsigned FirstVal, unsigned LastVal, bool isGlobal);
385   void writeModuleConstants();
386   bool pushValueAndType(const Value *V, unsigned InstID,
387                         SmallVectorImpl<unsigned> &Vals);
388   void writeOperandBundles(const CallBase &CB, unsigned InstID);
389   void pushValue(const Value *V, unsigned InstID,
390                  SmallVectorImpl<unsigned> &Vals);
391   void pushValueSigned(const Value *V, unsigned InstID,
392                        SmallVectorImpl<uint64_t> &Vals);
393   void writeInstruction(const Instruction &I, unsigned InstID,
394                         SmallVectorImpl<unsigned> &Vals);
395   void writeFunctionLevelValueSymbolTable(const ValueSymbolTable &VST);
396   void writeGlobalValueSymbolTable(
397       DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
398   void writeUseList(UseListOrder &&Order);
399   void writeUseListBlock(const Function *F);
400   void
401   writeFunction(const Function &F,
402                 DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
403   void writeBlockInfo();
404   void writeModuleHash(size_t BlockStartPos);
405 
406   unsigned getEncodedSyncScopeID(SyncScope::ID SSID) {
407     return unsigned(SSID);
408   }
409 
410   unsigned getEncodedAlign(MaybeAlign Alignment) { return encode(Alignment); }
411 };
412 
413 /// Class to manage the bitcode writing for a combined index.
414 class IndexBitcodeWriter : public BitcodeWriterBase {
415   /// The combined index to write to bitcode.
416   const ModuleSummaryIndex &Index;
417 
418   /// When writing a subset of the index for distributed backends, client
419   /// provides a map of modules to the corresponding GUIDs/summaries to write.
420   const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex;
421 
422   /// Map that holds the correspondence between the GUID used in the combined
423   /// index and a value id generated by this class to use in references.
424   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
425 
426   // The sorted stack id indices actually used in the summary entries being
427   // written, which will be a subset of those in the full index in the case of
428   // distributed indexes.
429   std::vector<unsigned> StackIdIndices;
430 
431   /// Tracks the last value id recorded in the GUIDToValueMap.
432   unsigned GlobalValueId = 0;
433 
434 public:
435   /// Constructs a IndexBitcodeWriter object for the given combined index,
436   /// writing to the provided \p Buffer. When writing a subset of the index
437   /// for a distributed backend, provide a \p ModuleToSummariesForIndex map.
438   IndexBitcodeWriter(BitstreamWriter &Stream, StringTableBuilder &StrtabBuilder,
439                      const ModuleSummaryIndex &Index,
440                      const std::map<std::string, GVSummaryMapTy>
441                          *ModuleToSummariesForIndex = nullptr)
442       : BitcodeWriterBase(Stream, StrtabBuilder), Index(Index),
443         ModuleToSummariesForIndex(ModuleToSummariesForIndex) {
444     // Assign unique value ids to all summaries to be written, for use
445     // in writing out the call graph edges. Save the mapping from GUID
446     // to the new global value id to use when writing those edges, which
447     // are currently saved in the index in terms of GUID.
448     forEachSummary([&](GVInfo I, bool IsAliasee) {
449       GUIDToValueIdMap[I.first] = ++GlobalValueId;
450       if (IsAliasee)
451         return;
452       auto *FS = dyn_cast<FunctionSummary>(I.second);
453       if (!FS)
454         return;
455       // Record all stack id indices actually used in the summary entries being
456       // written, so that we can compact them in the case of distributed ThinLTO
457       // indexes.
458       for (auto &CI : FS->callsites())
459         for (auto Idx : CI.StackIdIndices)
460           StackIdIndices.push_back(Idx);
461       for (auto &AI : FS->allocs())
462         for (auto &MIB : AI.MIBs)
463           for (auto Idx : MIB.StackIdIndices)
464             StackIdIndices.push_back(Idx);
465     });
466     llvm::sort(StackIdIndices);
467     StackIdIndices.erase(
468         std::unique(StackIdIndices.begin(), StackIdIndices.end()),
469         StackIdIndices.end());
470   }
471 
472   /// The below iterator returns the GUID and associated summary.
473   using GVInfo = std::pair<GlobalValue::GUID, GlobalValueSummary *>;
474 
475   /// Calls the callback for each value GUID and summary to be written to
476   /// bitcode. This hides the details of whether they are being pulled from the
477   /// entire index or just those in a provided ModuleToSummariesForIndex map.
478   template<typename Functor>
479   void forEachSummary(Functor Callback) {
480     if (ModuleToSummariesForIndex) {
481       for (auto &M : *ModuleToSummariesForIndex)
482         for (auto &Summary : M.second) {
483           Callback(Summary, false);
484           // Ensure aliasee is handled, e.g. for assigning a valueId,
485           // even if we are not importing the aliasee directly (the
486           // imported alias will contain a copy of aliasee).
487           if (auto *AS = dyn_cast<AliasSummary>(Summary.getSecond()))
488             Callback({AS->getAliaseeGUID(), &AS->getAliasee()}, true);
489         }
490     } else {
491       for (auto &Summaries : Index)
492         for (auto &Summary : Summaries.second.SummaryList)
493           Callback({Summaries.first, Summary.get()}, false);
494     }
495   }
496 
497   /// Calls the callback for each entry in the modulePaths StringMap that
498   /// should be written to the module path string table. This hides the details
499   /// of whether they are being pulled from the entire index or just those in a
500   /// provided ModuleToSummariesForIndex map.
501   template <typename Functor> void forEachModule(Functor Callback) {
502     if (ModuleToSummariesForIndex) {
503       for (const auto &M : *ModuleToSummariesForIndex) {
504         const auto &MPI = Index.modulePaths().find(M.first);
505         if (MPI == Index.modulePaths().end()) {
506           // This should only happen if the bitcode file was empty, in which
507           // case we shouldn't be importing (the ModuleToSummariesForIndex
508           // would only include the module we are writing and index for).
509           assert(ModuleToSummariesForIndex->size() == 1);
510           continue;
511         }
512         Callback(*MPI);
513       }
514     } else {
515       for (const auto &MPSE : Index.modulePaths())
516         Callback(MPSE);
517     }
518   }
519 
520   /// Main entry point for writing a combined index to bitcode.
521   void write();
522 
523 private:
524   void writeModStrings();
525   void writeCombinedGlobalValueSummary();
526 
527   std::optional<unsigned> getValueId(GlobalValue::GUID ValGUID) {
528     auto VMI = GUIDToValueIdMap.find(ValGUID);
529     if (VMI == GUIDToValueIdMap.end())
530       return std::nullopt;
531     return VMI->second;
532   }
533 
534   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
535 };
536 
537 } // end anonymous namespace
538 
539 static unsigned getEncodedCastOpcode(unsigned Opcode) {
540   switch (Opcode) {
541   default: llvm_unreachable("Unknown cast instruction!");
542   case Instruction::Trunc   : return bitc::CAST_TRUNC;
543   case Instruction::ZExt    : return bitc::CAST_ZEXT;
544   case Instruction::SExt    : return bitc::CAST_SEXT;
545   case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
546   case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
547   case Instruction::UIToFP  : return bitc::CAST_UITOFP;
548   case Instruction::SIToFP  : return bitc::CAST_SITOFP;
549   case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
550   case Instruction::FPExt   : return bitc::CAST_FPEXT;
551   case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
552   case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
553   case Instruction::BitCast : return bitc::CAST_BITCAST;
554   case Instruction::AddrSpaceCast: return bitc::CAST_ADDRSPACECAST;
555   }
556 }
557 
558 static unsigned getEncodedUnaryOpcode(unsigned Opcode) {
559   switch (Opcode) {
560   default: llvm_unreachable("Unknown binary instruction!");
561   case Instruction::FNeg: return bitc::UNOP_FNEG;
562   }
563 }
564 
565 static unsigned getEncodedBinaryOpcode(unsigned Opcode) {
566   switch (Opcode) {
567   default: llvm_unreachable("Unknown binary instruction!");
568   case Instruction::Add:
569   case Instruction::FAdd: return bitc::BINOP_ADD;
570   case Instruction::Sub:
571   case Instruction::FSub: return bitc::BINOP_SUB;
572   case Instruction::Mul:
573   case Instruction::FMul: return bitc::BINOP_MUL;
574   case Instruction::UDiv: return bitc::BINOP_UDIV;
575   case Instruction::FDiv:
576   case Instruction::SDiv: return bitc::BINOP_SDIV;
577   case Instruction::URem: return bitc::BINOP_UREM;
578   case Instruction::FRem:
579   case Instruction::SRem: return bitc::BINOP_SREM;
580   case Instruction::Shl:  return bitc::BINOP_SHL;
581   case Instruction::LShr: return bitc::BINOP_LSHR;
582   case Instruction::AShr: return bitc::BINOP_ASHR;
583   case Instruction::And:  return bitc::BINOP_AND;
584   case Instruction::Or:   return bitc::BINOP_OR;
585   case Instruction::Xor:  return bitc::BINOP_XOR;
586   }
587 }
588 
589 static unsigned getEncodedRMWOperation(AtomicRMWInst::BinOp Op) {
590   switch (Op) {
591   default: llvm_unreachable("Unknown RMW operation!");
592   case AtomicRMWInst::Xchg: return bitc::RMW_XCHG;
593   case AtomicRMWInst::Add: return bitc::RMW_ADD;
594   case AtomicRMWInst::Sub: return bitc::RMW_SUB;
595   case AtomicRMWInst::And: return bitc::RMW_AND;
596   case AtomicRMWInst::Nand: return bitc::RMW_NAND;
597   case AtomicRMWInst::Or: return bitc::RMW_OR;
598   case AtomicRMWInst::Xor: return bitc::RMW_XOR;
599   case AtomicRMWInst::Max: return bitc::RMW_MAX;
600   case AtomicRMWInst::Min: return bitc::RMW_MIN;
601   case AtomicRMWInst::UMax: return bitc::RMW_UMAX;
602   case AtomicRMWInst::UMin: return bitc::RMW_UMIN;
603   case AtomicRMWInst::FAdd: return bitc::RMW_FADD;
604   case AtomicRMWInst::FSub: return bitc::RMW_FSUB;
605   case AtomicRMWInst::FMax: return bitc::RMW_FMAX;
606   case AtomicRMWInst::FMin: return bitc::RMW_FMIN;
607   case AtomicRMWInst::UIncWrap:
608     return bitc::RMW_UINC_WRAP;
609   case AtomicRMWInst::UDecWrap:
610     return bitc::RMW_UDEC_WRAP;
611   }
612 }
613 
614 static unsigned getEncodedOrdering(AtomicOrdering Ordering) {
615   switch (Ordering) {
616   case AtomicOrdering::NotAtomic: return bitc::ORDERING_NOTATOMIC;
617   case AtomicOrdering::Unordered: return bitc::ORDERING_UNORDERED;
618   case AtomicOrdering::Monotonic: return bitc::ORDERING_MONOTONIC;
619   case AtomicOrdering::Acquire: return bitc::ORDERING_ACQUIRE;
620   case AtomicOrdering::Release: return bitc::ORDERING_RELEASE;
621   case AtomicOrdering::AcquireRelease: return bitc::ORDERING_ACQREL;
622   case AtomicOrdering::SequentiallyConsistent: return bitc::ORDERING_SEQCST;
623   }
624   llvm_unreachable("Invalid ordering");
625 }
626 
627 static void writeStringRecord(BitstreamWriter &Stream, unsigned Code,
628                               StringRef Str, unsigned AbbrevToUse) {
629   SmallVector<unsigned, 64> Vals;
630 
631   // Code: [strchar x N]
632   for (char C : Str) {
633     if (AbbrevToUse && !BitCodeAbbrevOp::isChar6(C))
634       AbbrevToUse = 0;
635     Vals.push_back(C);
636   }
637 
638   // Emit the finished record.
639   Stream.EmitRecord(Code, Vals, AbbrevToUse);
640 }
641 
642 static uint64_t getAttrKindEncoding(Attribute::AttrKind Kind) {
643   switch (Kind) {
644   case Attribute::Alignment:
645     return bitc::ATTR_KIND_ALIGNMENT;
646   case Attribute::AllocAlign:
647     return bitc::ATTR_KIND_ALLOC_ALIGN;
648   case Attribute::AllocSize:
649     return bitc::ATTR_KIND_ALLOC_SIZE;
650   case Attribute::AlwaysInline:
651     return bitc::ATTR_KIND_ALWAYS_INLINE;
652   case Attribute::Builtin:
653     return bitc::ATTR_KIND_BUILTIN;
654   case Attribute::ByVal:
655     return bitc::ATTR_KIND_BY_VAL;
656   case Attribute::Convergent:
657     return bitc::ATTR_KIND_CONVERGENT;
658   case Attribute::InAlloca:
659     return bitc::ATTR_KIND_IN_ALLOCA;
660   case Attribute::Cold:
661     return bitc::ATTR_KIND_COLD;
662   case Attribute::DisableSanitizerInstrumentation:
663     return bitc::ATTR_KIND_DISABLE_SANITIZER_INSTRUMENTATION;
664   case Attribute::FnRetThunkExtern:
665     return bitc::ATTR_KIND_FNRETTHUNK_EXTERN;
666   case Attribute::Hot:
667     return bitc::ATTR_KIND_HOT;
668   case Attribute::ElementType:
669     return bitc::ATTR_KIND_ELEMENTTYPE;
670   case Attribute::InlineHint:
671     return bitc::ATTR_KIND_INLINE_HINT;
672   case Attribute::InReg:
673     return bitc::ATTR_KIND_IN_REG;
674   case Attribute::JumpTable:
675     return bitc::ATTR_KIND_JUMP_TABLE;
676   case Attribute::MinSize:
677     return bitc::ATTR_KIND_MIN_SIZE;
678   case Attribute::AllocatedPointer:
679     return bitc::ATTR_KIND_ALLOCATED_POINTER;
680   case Attribute::AllocKind:
681     return bitc::ATTR_KIND_ALLOC_KIND;
682   case Attribute::Memory:
683     return bitc::ATTR_KIND_MEMORY;
684   case Attribute::NoFPClass:
685     return bitc::ATTR_KIND_NOFPCLASS;
686   case Attribute::Naked:
687     return bitc::ATTR_KIND_NAKED;
688   case Attribute::Nest:
689     return bitc::ATTR_KIND_NEST;
690   case Attribute::NoAlias:
691     return bitc::ATTR_KIND_NO_ALIAS;
692   case Attribute::NoBuiltin:
693     return bitc::ATTR_KIND_NO_BUILTIN;
694   case Attribute::NoCallback:
695     return bitc::ATTR_KIND_NO_CALLBACK;
696   case Attribute::NoCapture:
697     return bitc::ATTR_KIND_NO_CAPTURE;
698   case Attribute::NoDuplicate:
699     return bitc::ATTR_KIND_NO_DUPLICATE;
700   case Attribute::NoFree:
701     return bitc::ATTR_KIND_NOFREE;
702   case Attribute::NoImplicitFloat:
703     return bitc::ATTR_KIND_NO_IMPLICIT_FLOAT;
704   case Attribute::NoInline:
705     return bitc::ATTR_KIND_NO_INLINE;
706   case Attribute::NoRecurse:
707     return bitc::ATTR_KIND_NO_RECURSE;
708   case Attribute::NoMerge:
709     return bitc::ATTR_KIND_NO_MERGE;
710   case Attribute::NonLazyBind:
711     return bitc::ATTR_KIND_NON_LAZY_BIND;
712   case Attribute::NonNull:
713     return bitc::ATTR_KIND_NON_NULL;
714   case Attribute::Dereferenceable:
715     return bitc::ATTR_KIND_DEREFERENCEABLE;
716   case Attribute::DereferenceableOrNull:
717     return bitc::ATTR_KIND_DEREFERENCEABLE_OR_NULL;
718   case Attribute::NoRedZone:
719     return bitc::ATTR_KIND_NO_RED_ZONE;
720   case Attribute::NoReturn:
721     return bitc::ATTR_KIND_NO_RETURN;
722   case Attribute::NoSync:
723     return bitc::ATTR_KIND_NOSYNC;
724   case Attribute::NoCfCheck:
725     return bitc::ATTR_KIND_NOCF_CHECK;
726   case Attribute::NoProfile:
727     return bitc::ATTR_KIND_NO_PROFILE;
728   case Attribute::SkipProfile:
729     return bitc::ATTR_KIND_SKIP_PROFILE;
730   case Attribute::NoUnwind:
731     return bitc::ATTR_KIND_NO_UNWIND;
732   case Attribute::NoSanitizeBounds:
733     return bitc::ATTR_KIND_NO_SANITIZE_BOUNDS;
734   case Attribute::NoSanitizeCoverage:
735     return bitc::ATTR_KIND_NO_SANITIZE_COVERAGE;
736   case Attribute::NullPointerIsValid:
737     return bitc::ATTR_KIND_NULL_POINTER_IS_VALID;
738   case Attribute::OptForFuzzing:
739     return bitc::ATTR_KIND_OPT_FOR_FUZZING;
740   case Attribute::OptimizeForSize:
741     return bitc::ATTR_KIND_OPTIMIZE_FOR_SIZE;
742   case Attribute::OptimizeNone:
743     return bitc::ATTR_KIND_OPTIMIZE_NONE;
744   case Attribute::ReadNone:
745     return bitc::ATTR_KIND_READ_NONE;
746   case Attribute::ReadOnly:
747     return bitc::ATTR_KIND_READ_ONLY;
748   case Attribute::Returned:
749     return bitc::ATTR_KIND_RETURNED;
750   case Attribute::ReturnsTwice:
751     return bitc::ATTR_KIND_RETURNS_TWICE;
752   case Attribute::SExt:
753     return bitc::ATTR_KIND_S_EXT;
754   case Attribute::Speculatable:
755     return bitc::ATTR_KIND_SPECULATABLE;
756   case Attribute::StackAlignment:
757     return bitc::ATTR_KIND_STACK_ALIGNMENT;
758   case Attribute::StackProtect:
759     return bitc::ATTR_KIND_STACK_PROTECT;
760   case Attribute::StackProtectReq:
761     return bitc::ATTR_KIND_STACK_PROTECT_REQ;
762   case Attribute::StackProtectStrong:
763     return bitc::ATTR_KIND_STACK_PROTECT_STRONG;
764   case Attribute::SafeStack:
765     return bitc::ATTR_KIND_SAFESTACK;
766   case Attribute::ShadowCallStack:
767     return bitc::ATTR_KIND_SHADOWCALLSTACK;
768   case Attribute::StrictFP:
769     return bitc::ATTR_KIND_STRICT_FP;
770   case Attribute::StructRet:
771     return bitc::ATTR_KIND_STRUCT_RET;
772   case Attribute::SanitizeAddress:
773     return bitc::ATTR_KIND_SANITIZE_ADDRESS;
774   case Attribute::SanitizeHWAddress:
775     return bitc::ATTR_KIND_SANITIZE_HWADDRESS;
776   case Attribute::SanitizeThread:
777     return bitc::ATTR_KIND_SANITIZE_THREAD;
778   case Attribute::SanitizeMemory:
779     return bitc::ATTR_KIND_SANITIZE_MEMORY;
780   case Attribute::SpeculativeLoadHardening:
781     return bitc::ATTR_KIND_SPECULATIVE_LOAD_HARDENING;
782   case Attribute::SwiftError:
783     return bitc::ATTR_KIND_SWIFT_ERROR;
784   case Attribute::SwiftSelf:
785     return bitc::ATTR_KIND_SWIFT_SELF;
786   case Attribute::SwiftAsync:
787     return bitc::ATTR_KIND_SWIFT_ASYNC;
788   case Attribute::UWTable:
789     return bitc::ATTR_KIND_UW_TABLE;
790   case Attribute::VScaleRange:
791     return bitc::ATTR_KIND_VSCALE_RANGE;
792   case Attribute::WillReturn:
793     return bitc::ATTR_KIND_WILLRETURN;
794   case Attribute::WriteOnly:
795     return bitc::ATTR_KIND_WRITEONLY;
796   case Attribute::ZExt:
797     return bitc::ATTR_KIND_Z_EXT;
798   case Attribute::ImmArg:
799     return bitc::ATTR_KIND_IMMARG;
800   case Attribute::SanitizeMemTag:
801     return bitc::ATTR_KIND_SANITIZE_MEMTAG;
802   case Attribute::Preallocated:
803     return bitc::ATTR_KIND_PREALLOCATED;
804   case Attribute::NoUndef:
805     return bitc::ATTR_KIND_NOUNDEF;
806   case Attribute::ByRef:
807     return bitc::ATTR_KIND_BYREF;
808   case Attribute::MustProgress:
809     return bitc::ATTR_KIND_MUSTPROGRESS;
810   case Attribute::PresplitCoroutine:
811     return bitc::ATTR_KIND_PRESPLIT_COROUTINE;
812   case Attribute::EndAttrKinds:
813     llvm_unreachable("Can not encode end-attribute kinds marker.");
814   case Attribute::None:
815     llvm_unreachable("Can not encode none-attribute.");
816   case Attribute::EmptyKey:
817   case Attribute::TombstoneKey:
818     llvm_unreachable("Trying to encode EmptyKey/TombstoneKey");
819   }
820 
821   llvm_unreachable("Trying to encode unknown attribute");
822 }
823 
824 void ModuleBitcodeWriter::writeAttributeGroupTable() {
825   const std::vector<ValueEnumerator::IndexAndAttrSet> &AttrGrps =
826       VE.getAttributeGroups();
827   if (AttrGrps.empty()) return;
828 
829   Stream.EnterSubblock(bitc::PARAMATTR_GROUP_BLOCK_ID, 3);
830 
831   SmallVector<uint64_t, 64> Record;
832   for (ValueEnumerator::IndexAndAttrSet Pair : AttrGrps) {
833     unsigned AttrListIndex = Pair.first;
834     AttributeSet AS = Pair.second;
835     Record.push_back(VE.getAttributeGroupID(Pair));
836     Record.push_back(AttrListIndex);
837 
838     for (Attribute Attr : AS) {
839       if (Attr.isEnumAttribute()) {
840         Record.push_back(0);
841         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
842       } else if (Attr.isIntAttribute()) {
843         Record.push_back(1);
844         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
845         Record.push_back(Attr.getValueAsInt());
846       } else if (Attr.isStringAttribute()) {
847         StringRef Kind = Attr.getKindAsString();
848         StringRef Val = Attr.getValueAsString();
849 
850         Record.push_back(Val.empty() ? 3 : 4);
851         Record.append(Kind.begin(), Kind.end());
852         Record.push_back(0);
853         if (!Val.empty()) {
854           Record.append(Val.begin(), Val.end());
855           Record.push_back(0);
856         }
857       } else {
858         assert(Attr.isTypeAttribute());
859         Type *Ty = Attr.getValueAsType();
860         Record.push_back(Ty ? 6 : 5);
861         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
862         if (Ty)
863           Record.push_back(VE.getTypeID(Attr.getValueAsType()));
864       }
865     }
866 
867     Stream.EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
868     Record.clear();
869   }
870 
871   Stream.ExitBlock();
872 }
873 
874 void ModuleBitcodeWriter::writeAttributeTable() {
875   const std::vector<AttributeList> &Attrs = VE.getAttributeLists();
876   if (Attrs.empty()) return;
877 
878   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
879 
880   SmallVector<uint64_t, 64> Record;
881   for (const AttributeList &AL : Attrs) {
882     for (unsigned i : AL.indexes()) {
883       AttributeSet AS = AL.getAttributes(i);
884       if (AS.hasAttributes())
885         Record.push_back(VE.getAttributeGroupID({i, AS}));
886     }
887 
888     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
889     Record.clear();
890   }
891 
892   Stream.ExitBlock();
893 }
894 
895 /// WriteTypeTable - Write out the type table for a module.
896 void ModuleBitcodeWriter::writeTypeTable() {
897   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
898 
899   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
900   SmallVector<uint64_t, 64> TypeVals;
901 
902   uint64_t NumBits = VE.computeBitsRequiredForTypeIndicies();
903 
904   // Abbrev for TYPE_CODE_POINTER.
905   auto Abbv = std::make_shared<BitCodeAbbrev>();
906   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
907   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
908   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
909   unsigned PtrAbbrev = Stream.EmitAbbrev(std::move(Abbv));
910 
911   // Abbrev for TYPE_CODE_OPAQUE_POINTER.
912   Abbv = std::make_shared<BitCodeAbbrev>();
913   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_OPAQUE_POINTER));
914   Abbv->Add(BitCodeAbbrevOp(0)); // Addrspace = 0
915   unsigned OpaquePtrAbbrev = Stream.EmitAbbrev(std::move(Abbv));
916 
917   // Abbrev for TYPE_CODE_FUNCTION.
918   Abbv = std::make_shared<BitCodeAbbrev>();
919   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
920   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
921   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
922   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
923   unsigned FunctionAbbrev = Stream.EmitAbbrev(std::move(Abbv));
924 
925   // Abbrev for TYPE_CODE_STRUCT_ANON.
926   Abbv = std::make_shared<BitCodeAbbrev>();
927   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
928   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
929   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
930   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
931   unsigned StructAnonAbbrev = Stream.EmitAbbrev(std::move(Abbv));
932 
933   // Abbrev for TYPE_CODE_STRUCT_NAME.
934   Abbv = std::make_shared<BitCodeAbbrev>();
935   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
936   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
937   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
938   unsigned StructNameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
939 
940   // Abbrev for TYPE_CODE_STRUCT_NAMED.
941   Abbv = std::make_shared<BitCodeAbbrev>();
942   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
943   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
944   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
945   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
946   unsigned StructNamedAbbrev = Stream.EmitAbbrev(std::move(Abbv));
947 
948   // Abbrev for TYPE_CODE_ARRAY.
949   Abbv = std::make_shared<BitCodeAbbrev>();
950   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
951   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
952   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
953   unsigned ArrayAbbrev = Stream.EmitAbbrev(std::move(Abbv));
954 
955   // Emit an entry count so the reader can reserve space.
956   TypeVals.push_back(TypeList.size());
957   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
958   TypeVals.clear();
959 
960   // Loop over all of the types, emitting each in turn.
961   for (Type *T : TypeList) {
962     int AbbrevToUse = 0;
963     unsigned Code = 0;
964 
965     switch (T->getTypeID()) {
966     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;      break;
967     case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;      break;
968     case Type::BFloatTyID:    Code = bitc::TYPE_CODE_BFLOAT;    break;
969     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;     break;
970     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE;    break;
971     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80;  break;
972     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128;     break;
973     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
974     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;     break;
975     case Type::MetadataTyID:  Code = bitc::TYPE_CODE_METADATA;  break;
976     case Type::X86_MMXTyID:   Code = bitc::TYPE_CODE_X86_MMX;   break;
977     case Type::X86_AMXTyID:   Code = bitc::TYPE_CODE_X86_AMX;   break;
978     case Type::TokenTyID:     Code = bitc::TYPE_CODE_TOKEN;     break;
979     case Type::IntegerTyID:
980       // INTEGER: [width]
981       Code = bitc::TYPE_CODE_INTEGER;
982       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
983       break;
984     case Type::PointerTyID: {
985       PointerType *PTy = cast<PointerType>(T);
986       unsigned AddressSpace = PTy->getAddressSpace();
987       if (PTy->isOpaque()) {
988         // OPAQUE_POINTER: [address space]
989         Code = bitc::TYPE_CODE_OPAQUE_POINTER;
990         TypeVals.push_back(AddressSpace);
991         if (AddressSpace == 0)
992           AbbrevToUse = OpaquePtrAbbrev;
993       } else {
994         // POINTER: [pointee type, address space]
995         Code = bitc::TYPE_CODE_POINTER;
996         TypeVals.push_back(VE.getTypeID(PTy->getNonOpaquePointerElementType()));
997         TypeVals.push_back(AddressSpace);
998         if (AddressSpace == 0)
999           AbbrevToUse = PtrAbbrev;
1000       }
1001       break;
1002     }
1003     case Type::FunctionTyID: {
1004       FunctionType *FT = cast<FunctionType>(T);
1005       // FUNCTION: [isvararg, retty, paramty x N]
1006       Code = bitc::TYPE_CODE_FUNCTION;
1007       TypeVals.push_back(FT->isVarArg());
1008       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
1009       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
1010         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
1011       AbbrevToUse = FunctionAbbrev;
1012       break;
1013     }
1014     case Type::StructTyID: {
1015       StructType *ST = cast<StructType>(T);
1016       // STRUCT: [ispacked, eltty x N]
1017       TypeVals.push_back(ST->isPacked());
1018       // Output all of the element types.
1019       for (Type *ET : ST->elements())
1020         TypeVals.push_back(VE.getTypeID(ET));
1021 
1022       if (ST->isLiteral()) {
1023         Code = bitc::TYPE_CODE_STRUCT_ANON;
1024         AbbrevToUse = StructAnonAbbrev;
1025       } else {
1026         if (ST->isOpaque()) {
1027           Code = bitc::TYPE_CODE_OPAQUE;
1028         } else {
1029           Code = bitc::TYPE_CODE_STRUCT_NAMED;
1030           AbbrevToUse = StructNamedAbbrev;
1031         }
1032 
1033         // Emit the name if it is present.
1034         if (!ST->getName().empty())
1035           writeStringRecord(Stream, bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
1036                             StructNameAbbrev);
1037       }
1038       break;
1039     }
1040     case Type::ArrayTyID: {
1041       ArrayType *AT = cast<ArrayType>(T);
1042       // ARRAY: [numelts, eltty]
1043       Code = bitc::TYPE_CODE_ARRAY;
1044       TypeVals.push_back(AT->getNumElements());
1045       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
1046       AbbrevToUse = ArrayAbbrev;
1047       break;
1048     }
1049     case Type::FixedVectorTyID:
1050     case Type::ScalableVectorTyID: {
1051       VectorType *VT = cast<VectorType>(T);
1052       // VECTOR [numelts, eltty] or
1053       //        [numelts, eltty, scalable]
1054       Code = bitc::TYPE_CODE_VECTOR;
1055       TypeVals.push_back(VT->getElementCount().getKnownMinValue());
1056       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
1057       if (isa<ScalableVectorType>(VT))
1058         TypeVals.push_back(true);
1059       break;
1060     }
1061     case Type::TargetExtTyID: {
1062       TargetExtType *TET = cast<TargetExtType>(T);
1063       Code = bitc::TYPE_CODE_TARGET_TYPE;
1064       writeStringRecord(Stream, bitc::TYPE_CODE_STRUCT_NAME, TET->getName(),
1065                         StructNameAbbrev);
1066       TypeVals.push_back(TET->getNumTypeParameters());
1067       for (Type *InnerTy : TET->type_params())
1068         TypeVals.push_back(VE.getTypeID(InnerTy));
1069       for (unsigned IntParam : TET->int_params())
1070         TypeVals.push_back(IntParam);
1071       break;
1072     }
1073     case Type::TypedPointerTyID:
1074       llvm_unreachable("Typed pointers cannot be added to IR modules");
1075     }
1076 
1077     // Emit the finished record.
1078     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
1079     TypeVals.clear();
1080   }
1081 
1082   Stream.ExitBlock();
1083 }
1084 
1085 static unsigned getEncodedLinkage(const GlobalValue::LinkageTypes Linkage) {
1086   switch (Linkage) {
1087   case GlobalValue::ExternalLinkage:
1088     return 0;
1089   case GlobalValue::WeakAnyLinkage:
1090     return 16;
1091   case GlobalValue::AppendingLinkage:
1092     return 2;
1093   case GlobalValue::InternalLinkage:
1094     return 3;
1095   case GlobalValue::LinkOnceAnyLinkage:
1096     return 18;
1097   case GlobalValue::ExternalWeakLinkage:
1098     return 7;
1099   case GlobalValue::CommonLinkage:
1100     return 8;
1101   case GlobalValue::PrivateLinkage:
1102     return 9;
1103   case GlobalValue::WeakODRLinkage:
1104     return 17;
1105   case GlobalValue::LinkOnceODRLinkage:
1106     return 19;
1107   case GlobalValue::AvailableExternallyLinkage:
1108     return 12;
1109   }
1110   llvm_unreachable("Invalid linkage");
1111 }
1112 
1113 static unsigned getEncodedLinkage(const GlobalValue &GV) {
1114   return getEncodedLinkage(GV.getLinkage());
1115 }
1116 
1117 static uint64_t getEncodedFFlags(FunctionSummary::FFlags Flags) {
1118   uint64_t RawFlags = 0;
1119   RawFlags |= Flags.ReadNone;
1120   RawFlags |= (Flags.ReadOnly << 1);
1121   RawFlags |= (Flags.NoRecurse << 2);
1122   RawFlags |= (Flags.ReturnDoesNotAlias << 3);
1123   RawFlags |= (Flags.NoInline << 4);
1124   RawFlags |= (Flags.AlwaysInline << 5);
1125   RawFlags |= (Flags.NoUnwind << 6);
1126   RawFlags |= (Flags.MayThrow << 7);
1127   RawFlags |= (Flags.HasUnknownCall << 8);
1128   RawFlags |= (Flags.MustBeUnreachable << 9);
1129   return RawFlags;
1130 }
1131 
1132 // Decode the flags for GlobalValue in the summary. See getDecodedGVSummaryFlags
1133 // in BitcodeReader.cpp.
1134 static uint64_t getEncodedGVSummaryFlags(GlobalValueSummary::GVFlags Flags) {
1135   uint64_t RawFlags = 0;
1136 
1137   RawFlags |= Flags.NotEligibleToImport; // bool
1138   RawFlags |= (Flags.Live << 1);
1139   RawFlags |= (Flags.DSOLocal << 2);
1140   RawFlags |= (Flags.CanAutoHide << 3);
1141 
1142   // Linkage don't need to be remapped at that time for the summary. Any future
1143   // change to the getEncodedLinkage() function will need to be taken into
1144   // account here as well.
1145   RawFlags = (RawFlags << 4) | Flags.Linkage; // 4 bits
1146 
1147   RawFlags |= (Flags.Visibility << 8); // 2 bits
1148 
1149   return RawFlags;
1150 }
1151 
1152 static uint64_t getEncodedGVarFlags(GlobalVarSummary::GVarFlags Flags) {
1153   uint64_t RawFlags = Flags.MaybeReadOnly | (Flags.MaybeWriteOnly << 1) |
1154                       (Flags.Constant << 2) | Flags.VCallVisibility << 3;
1155   return RawFlags;
1156 }
1157 
1158 static unsigned getEncodedVisibility(const GlobalValue &GV) {
1159   switch (GV.getVisibility()) {
1160   case GlobalValue::DefaultVisibility:   return 0;
1161   case GlobalValue::HiddenVisibility:    return 1;
1162   case GlobalValue::ProtectedVisibility: return 2;
1163   }
1164   llvm_unreachable("Invalid visibility");
1165 }
1166 
1167 static unsigned getEncodedDLLStorageClass(const GlobalValue &GV) {
1168   switch (GV.getDLLStorageClass()) {
1169   case GlobalValue::DefaultStorageClass:   return 0;
1170   case GlobalValue::DLLImportStorageClass: return 1;
1171   case GlobalValue::DLLExportStorageClass: return 2;
1172   }
1173   llvm_unreachable("Invalid DLL storage class");
1174 }
1175 
1176 static unsigned getEncodedThreadLocalMode(const GlobalValue &GV) {
1177   switch (GV.getThreadLocalMode()) {
1178     case GlobalVariable::NotThreadLocal:         return 0;
1179     case GlobalVariable::GeneralDynamicTLSModel: return 1;
1180     case GlobalVariable::LocalDynamicTLSModel:   return 2;
1181     case GlobalVariable::InitialExecTLSModel:    return 3;
1182     case GlobalVariable::LocalExecTLSModel:      return 4;
1183   }
1184   llvm_unreachable("Invalid TLS model");
1185 }
1186 
1187 static unsigned getEncodedComdatSelectionKind(const Comdat &C) {
1188   switch (C.getSelectionKind()) {
1189   case Comdat::Any:
1190     return bitc::COMDAT_SELECTION_KIND_ANY;
1191   case Comdat::ExactMatch:
1192     return bitc::COMDAT_SELECTION_KIND_EXACT_MATCH;
1193   case Comdat::Largest:
1194     return bitc::COMDAT_SELECTION_KIND_LARGEST;
1195   case Comdat::NoDeduplicate:
1196     return bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES;
1197   case Comdat::SameSize:
1198     return bitc::COMDAT_SELECTION_KIND_SAME_SIZE;
1199   }
1200   llvm_unreachable("Invalid selection kind");
1201 }
1202 
1203 static unsigned getEncodedUnnamedAddr(const GlobalValue &GV) {
1204   switch (GV.getUnnamedAddr()) {
1205   case GlobalValue::UnnamedAddr::None:   return 0;
1206   case GlobalValue::UnnamedAddr::Local:  return 2;
1207   case GlobalValue::UnnamedAddr::Global: return 1;
1208   }
1209   llvm_unreachable("Invalid unnamed_addr");
1210 }
1211 
1212 size_t ModuleBitcodeWriter::addToStrtab(StringRef Str) {
1213   if (GenerateHash)
1214     Hasher.update(Str);
1215   return StrtabBuilder.add(Str);
1216 }
1217 
1218 void ModuleBitcodeWriter::writeComdats() {
1219   SmallVector<unsigned, 64> Vals;
1220   for (const Comdat *C : VE.getComdats()) {
1221     // COMDAT: [strtab offset, strtab size, selection_kind]
1222     Vals.push_back(addToStrtab(C->getName()));
1223     Vals.push_back(C->getName().size());
1224     Vals.push_back(getEncodedComdatSelectionKind(*C));
1225     Stream.EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
1226     Vals.clear();
1227   }
1228 }
1229 
1230 /// Write a record that will eventually hold the word offset of the
1231 /// module-level VST. For now the offset is 0, which will be backpatched
1232 /// after the real VST is written. Saves the bit offset to backpatch.
1233 void ModuleBitcodeWriter::writeValueSymbolTableForwardDecl() {
1234   // Write a placeholder value in for the offset of the real VST,
1235   // which is written after the function blocks so that it can include
1236   // the offset of each function. The placeholder offset will be
1237   // updated when the real VST is written.
1238   auto Abbv = std::make_shared<BitCodeAbbrev>();
1239   Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_VSTOFFSET));
1240   // Blocks are 32-bit aligned, so we can use a 32-bit word offset to
1241   // hold the real VST offset. Must use fixed instead of VBR as we don't
1242   // know how many VBR chunks to reserve ahead of time.
1243   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
1244   unsigned VSTOffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1245 
1246   // Emit the placeholder
1247   uint64_t Vals[] = {bitc::MODULE_CODE_VSTOFFSET, 0};
1248   Stream.EmitRecordWithAbbrev(VSTOffsetAbbrev, Vals);
1249 
1250   // Compute and save the bit offset to the placeholder, which will be
1251   // patched when the real VST is written. We can simply subtract the 32-bit
1252   // fixed size from the current bit number to get the location to backpatch.
1253   VSTOffsetPlaceholder = Stream.GetCurrentBitNo() - 32;
1254 }
1255 
1256 enum StringEncoding { SE_Char6, SE_Fixed7, SE_Fixed8 };
1257 
1258 /// Determine the encoding to use for the given string name and length.
1259 static StringEncoding getStringEncoding(StringRef Str) {
1260   bool isChar6 = true;
1261   for (char C : Str) {
1262     if (isChar6)
1263       isChar6 = BitCodeAbbrevOp::isChar6(C);
1264     if ((unsigned char)C & 128)
1265       // don't bother scanning the rest.
1266       return SE_Fixed8;
1267   }
1268   if (isChar6)
1269     return SE_Char6;
1270   return SE_Fixed7;
1271 }
1272 
1273 static_assert(sizeof(GlobalValue::SanitizerMetadata) <= sizeof(unsigned),
1274               "Sanitizer Metadata is too large for naive serialization.");
1275 static unsigned
1276 serializeSanitizerMetadata(const GlobalValue::SanitizerMetadata &Meta) {
1277   return Meta.NoAddress | (Meta.NoHWAddress << 1) |
1278          (Meta.Memtag << 2) | (Meta.IsDynInit << 3);
1279 }
1280 
1281 /// Emit top-level description of module, including target triple, inline asm,
1282 /// descriptors for global variables, and function prototype info.
1283 /// Returns the bit offset to backpatch with the location of the real VST.
1284 void ModuleBitcodeWriter::writeModuleInfo() {
1285   // Emit various pieces of data attached to a module.
1286   if (!M.getTargetTriple().empty())
1287     writeStringRecord(Stream, bitc::MODULE_CODE_TRIPLE, M.getTargetTriple(),
1288                       0 /*TODO*/);
1289   const std::string &DL = M.getDataLayoutStr();
1290   if (!DL.empty())
1291     writeStringRecord(Stream, bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/);
1292   if (!M.getModuleInlineAsm().empty())
1293     writeStringRecord(Stream, bitc::MODULE_CODE_ASM, M.getModuleInlineAsm(),
1294                       0 /*TODO*/);
1295 
1296   // Emit information about sections and GC, computing how many there are. Also
1297   // compute the maximum alignment value.
1298   std::map<std::string, unsigned> SectionMap;
1299   std::map<std::string, unsigned> GCMap;
1300   MaybeAlign MaxAlignment;
1301   unsigned MaxGlobalType = 0;
1302   const auto UpdateMaxAlignment = [&MaxAlignment](const MaybeAlign A) {
1303     if (A)
1304       MaxAlignment = !MaxAlignment ? *A : std::max(*MaxAlignment, *A);
1305   };
1306   for (const GlobalVariable &GV : M.globals()) {
1307     UpdateMaxAlignment(GV.getAlign());
1308     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getValueType()));
1309     if (GV.hasSection()) {
1310       // Give section names unique ID's.
1311       unsigned &Entry = SectionMap[std::string(GV.getSection())];
1312       if (!Entry) {
1313         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
1314                           0 /*TODO*/);
1315         Entry = SectionMap.size();
1316       }
1317     }
1318   }
1319   for (const Function &F : M) {
1320     UpdateMaxAlignment(F.getAlign());
1321     if (F.hasSection()) {
1322       // Give section names unique ID's.
1323       unsigned &Entry = SectionMap[std::string(F.getSection())];
1324       if (!Entry) {
1325         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
1326                           0 /*TODO*/);
1327         Entry = SectionMap.size();
1328       }
1329     }
1330     if (F.hasGC()) {
1331       // Same for GC names.
1332       unsigned &Entry = GCMap[F.getGC()];
1333       if (!Entry) {
1334         writeStringRecord(Stream, bitc::MODULE_CODE_GCNAME, F.getGC(),
1335                           0 /*TODO*/);
1336         Entry = GCMap.size();
1337       }
1338     }
1339   }
1340 
1341   // Emit abbrev for globals, now that we know # sections and max alignment.
1342   unsigned SimpleGVarAbbrev = 0;
1343   if (!M.global_empty()) {
1344     // Add an abbrev for common globals with no visibility or thread localness.
1345     auto Abbv = std::make_shared<BitCodeAbbrev>();
1346     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
1347     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1348     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1349     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1350                               Log2_32_Ceil(MaxGlobalType+1)));
1351     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddrSpace << 2
1352                                                            //| explicitType << 1
1353                                                            //| constant
1354     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Initializer.
1355     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // Linkage.
1356     if (!MaxAlignment)                                     // Alignment.
1357       Abbv->Add(BitCodeAbbrevOp(0));
1358     else {
1359       unsigned MaxEncAlignment = getEncodedAlign(MaxAlignment);
1360       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1361                                Log2_32_Ceil(MaxEncAlignment+1)));
1362     }
1363     if (SectionMap.empty())                                    // Section.
1364       Abbv->Add(BitCodeAbbrevOp(0));
1365     else
1366       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1367                                Log2_32_Ceil(SectionMap.size()+1)));
1368     // Don't bother emitting vis + thread local.
1369     SimpleGVarAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1370   }
1371 
1372   SmallVector<unsigned, 64> Vals;
1373   // Emit the module's source file name.
1374   {
1375     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
1376     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
1377     if (Bits == SE_Char6)
1378       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
1379     else if (Bits == SE_Fixed7)
1380       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
1381 
1382     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
1383     auto Abbv = std::make_shared<BitCodeAbbrev>();
1384     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
1385     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1386     Abbv->Add(AbbrevOpToUse);
1387     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1388 
1389     for (const auto P : M.getSourceFileName())
1390       Vals.push_back((unsigned char)P);
1391 
1392     // Emit the finished record.
1393     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
1394     Vals.clear();
1395   }
1396 
1397   // Emit the global variable information.
1398   for (const GlobalVariable &GV : M.globals()) {
1399     unsigned AbbrevToUse = 0;
1400 
1401     // GLOBALVAR: [strtab offset, strtab size, type, isconst, initid,
1402     //             linkage, alignment, section, visibility, threadlocal,
1403     //             unnamed_addr, externally_initialized, dllstorageclass,
1404     //             comdat, attributes, DSO_Local, GlobalSanitizer]
1405     Vals.push_back(addToStrtab(GV.getName()));
1406     Vals.push_back(GV.getName().size());
1407     Vals.push_back(VE.getTypeID(GV.getValueType()));
1408     Vals.push_back(GV.getType()->getAddressSpace() << 2 | 2 | GV.isConstant());
1409     Vals.push_back(GV.isDeclaration() ? 0 :
1410                    (VE.getValueID(GV.getInitializer()) + 1));
1411     Vals.push_back(getEncodedLinkage(GV));
1412     Vals.push_back(getEncodedAlign(GV.getAlign()));
1413     Vals.push_back(GV.hasSection() ? SectionMap[std::string(GV.getSection())]
1414                                    : 0);
1415     if (GV.isThreadLocal() ||
1416         GV.getVisibility() != GlobalValue::DefaultVisibility ||
1417         GV.getUnnamedAddr() != GlobalValue::UnnamedAddr::None ||
1418         GV.isExternallyInitialized() ||
1419         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
1420         GV.hasComdat() || GV.hasAttributes() || GV.isDSOLocal() ||
1421         GV.hasPartition() || GV.hasSanitizerMetadata()) {
1422       Vals.push_back(getEncodedVisibility(GV));
1423       Vals.push_back(getEncodedThreadLocalMode(GV));
1424       Vals.push_back(getEncodedUnnamedAddr(GV));
1425       Vals.push_back(GV.isExternallyInitialized());
1426       Vals.push_back(getEncodedDLLStorageClass(GV));
1427       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
1428 
1429       auto AL = GV.getAttributesAsList(AttributeList::FunctionIndex);
1430       Vals.push_back(VE.getAttributeListID(AL));
1431 
1432       Vals.push_back(GV.isDSOLocal());
1433       Vals.push_back(addToStrtab(GV.getPartition()));
1434       Vals.push_back(GV.getPartition().size());
1435 
1436       Vals.push_back((GV.hasSanitizerMetadata() ? serializeSanitizerMetadata(
1437                                                       GV.getSanitizerMetadata())
1438                                                 : 0));
1439     } else {
1440       AbbrevToUse = SimpleGVarAbbrev;
1441     }
1442 
1443     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
1444     Vals.clear();
1445   }
1446 
1447   // Emit the function proto information.
1448   for (const Function &F : M) {
1449     // FUNCTION:  [strtab offset, strtab size, type, callingconv, isproto,
1450     //             linkage, paramattrs, alignment, section, visibility, gc,
1451     //             unnamed_addr, prologuedata, dllstorageclass, comdat,
1452     //             prefixdata, personalityfn, DSO_Local, addrspace]
1453     Vals.push_back(addToStrtab(F.getName()));
1454     Vals.push_back(F.getName().size());
1455     Vals.push_back(VE.getTypeID(F.getFunctionType()));
1456     Vals.push_back(F.getCallingConv());
1457     Vals.push_back(F.isDeclaration());
1458     Vals.push_back(getEncodedLinkage(F));
1459     Vals.push_back(VE.getAttributeListID(F.getAttributes()));
1460     Vals.push_back(getEncodedAlign(F.getAlign()));
1461     Vals.push_back(F.hasSection() ? SectionMap[std::string(F.getSection())]
1462                                   : 0);
1463     Vals.push_back(getEncodedVisibility(F));
1464     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
1465     Vals.push_back(getEncodedUnnamedAddr(F));
1466     Vals.push_back(F.hasPrologueData() ? (VE.getValueID(F.getPrologueData()) + 1)
1467                                        : 0);
1468     Vals.push_back(getEncodedDLLStorageClass(F));
1469     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
1470     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
1471                                      : 0);
1472     Vals.push_back(
1473         F.hasPersonalityFn() ? (VE.getValueID(F.getPersonalityFn()) + 1) : 0);
1474 
1475     Vals.push_back(F.isDSOLocal());
1476     Vals.push_back(F.getAddressSpace());
1477     Vals.push_back(addToStrtab(F.getPartition()));
1478     Vals.push_back(F.getPartition().size());
1479 
1480     unsigned AbbrevToUse = 0;
1481     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
1482     Vals.clear();
1483   }
1484 
1485   // Emit the alias information.
1486   for (const GlobalAlias &A : M.aliases()) {
1487     // ALIAS: [strtab offset, strtab size, alias type, aliasee val#, linkage,
1488     //         visibility, dllstorageclass, threadlocal, unnamed_addr,
1489     //         DSO_Local]
1490     Vals.push_back(addToStrtab(A.getName()));
1491     Vals.push_back(A.getName().size());
1492     Vals.push_back(VE.getTypeID(A.getValueType()));
1493     Vals.push_back(A.getType()->getAddressSpace());
1494     Vals.push_back(VE.getValueID(A.getAliasee()));
1495     Vals.push_back(getEncodedLinkage(A));
1496     Vals.push_back(getEncodedVisibility(A));
1497     Vals.push_back(getEncodedDLLStorageClass(A));
1498     Vals.push_back(getEncodedThreadLocalMode(A));
1499     Vals.push_back(getEncodedUnnamedAddr(A));
1500     Vals.push_back(A.isDSOLocal());
1501     Vals.push_back(addToStrtab(A.getPartition()));
1502     Vals.push_back(A.getPartition().size());
1503 
1504     unsigned AbbrevToUse = 0;
1505     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
1506     Vals.clear();
1507   }
1508 
1509   // Emit the ifunc information.
1510   for (const GlobalIFunc &I : M.ifuncs()) {
1511     // IFUNC: [strtab offset, strtab size, ifunc type, address space, resolver
1512     //         val#, linkage, visibility, DSO_Local]
1513     Vals.push_back(addToStrtab(I.getName()));
1514     Vals.push_back(I.getName().size());
1515     Vals.push_back(VE.getTypeID(I.getValueType()));
1516     Vals.push_back(I.getType()->getAddressSpace());
1517     Vals.push_back(VE.getValueID(I.getResolver()));
1518     Vals.push_back(getEncodedLinkage(I));
1519     Vals.push_back(getEncodedVisibility(I));
1520     Vals.push_back(I.isDSOLocal());
1521     Vals.push_back(addToStrtab(I.getPartition()));
1522     Vals.push_back(I.getPartition().size());
1523     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
1524     Vals.clear();
1525   }
1526 
1527   writeValueSymbolTableForwardDecl();
1528 }
1529 
1530 static uint64_t getOptimizationFlags(const Value *V) {
1531   uint64_t Flags = 0;
1532 
1533   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
1534     if (OBO->hasNoSignedWrap())
1535       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
1536     if (OBO->hasNoUnsignedWrap())
1537       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
1538   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
1539     if (PEO->isExact())
1540       Flags |= 1 << bitc::PEO_EXACT;
1541   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
1542     if (FPMO->hasAllowReassoc())
1543       Flags |= bitc::AllowReassoc;
1544     if (FPMO->hasNoNaNs())
1545       Flags |= bitc::NoNaNs;
1546     if (FPMO->hasNoInfs())
1547       Flags |= bitc::NoInfs;
1548     if (FPMO->hasNoSignedZeros())
1549       Flags |= bitc::NoSignedZeros;
1550     if (FPMO->hasAllowReciprocal())
1551       Flags |= bitc::AllowReciprocal;
1552     if (FPMO->hasAllowContract())
1553       Flags |= bitc::AllowContract;
1554     if (FPMO->hasApproxFunc())
1555       Flags |= bitc::ApproxFunc;
1556   }
1557 
1558   return Flags;
1559 }
1560 
1561 void ModuleBitcodeWriter::writeValueAsMetadata(
1562     const ValueAsMetadata *MD, SmallVectorImpl<uint64_t> &Record) {
1563   // Mimic an MDNode with a value as one operand.
1564   Value *V = MD->getValue();
1565   Record.push_back(VE.getTypeID(V->getType()));
1566   Record.push_back(VE.getValueID(V));
1567   Stream.EmitRecord(bitc::METADATA_VALUE, Record, 0);
1568   Record.clear();
1569 }
1570 
1571 void ModuleBitcodeWriter::writeMDTuple(const MDTuple *N,
1572                                        SmallVectorImpl<uint64_t> &Record,
1573                                        unsigned Abbrev) {
1574   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
1575     Metadata *MD = N->getOperand(i);
1576     assert(!(MD && isa<LocalAsMetadata>(MD)) &&
1577            "Unexpected function-local metadata");
1578     Record.push_back(VE.getMetadataOrNullID(MD));
1579   }
1580   Stream.EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
1581                                     : bitc::METADATA_NODE,
1582                     Record, Abbrev);
1583   Record.clear();
1584 }
1585 
1586 unsigned ModuleBitcodeWriter::createDILocationAbbrev() {
1587   // Assume the column is usually under 128, and always output the inlined-at
1588   // location (it's never more expensive than building an array size 1).
1589   auto Abbv = std::make_shared<BitCodeAbbrev>();
1590   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
1591   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1592   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1593   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1594   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1595   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1596   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1597   return Stream.EmitAbbrev(std::move(Abbv));
1598 }
1599 
1600 void ModuleBitcodeWriter::writeDILocation(const DILocation *N,
1601                                           SmallVectorImpl<uint64_t> &Record,
1602                                           unsigned &Abbrev) {
1603   if (!Abbrev)
1604     Abbrev = createDILocationAbbrev();
1605 
1606   Record.push_back(N->isDistinct());
1607   Record.push_back(N->getLine());
1608   Record.push_back(N->getColumn());
1609   Record.push_back(VE.getMetadataID(N->getScope()));
1610   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
1611   Record.push_back(N->isImplicitCode());
1612 
1613   Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
1614   Record.clear();
1615 }
1616 
1617 unsigned ModuleBitcodeWriter::createGenericDINodeAbbrev() {
1618   // Assume the column is usually under 128, and always output the inlined-at
1619   // location (it's never more expensive than building an array size 1).
1620   auto Abbv = std::make_shared<BitCodeAbbrev>();
1621   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
1622   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1623   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1624   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1625   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1626   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1627   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1628   return Stream.EmitAbbrev(std::move(Abbv));
1629 }
1630 
1631 void ModuleBitcodeWriter::writeGenericDINode(const GenericDINode *N,
1632                                              SmallVectorImpl<uint64_t> &Record,
1633                                              unsigned &Abbrev) {
1634   if (!Abbrev)
1635     Abbrev = createGenericDINodeAbbrev();
1636 
1637   Record.push_back(N->isDistinct());
1638   Record.push_back(N->getTag());
1639   Record.push_back(0); // Per-tag version field; unused for now.
1640 
1641   for (auto &I : N->operands())
1642     Record.push_back(VE.getMetadataOrNullID(I));
1643 
1644   Stream.EmitRecord(bitc::METADATA_GENERIC_DEBUG, Record, Abbrev);
1645   Record.clear();
1646 }
1647 
1648 void ModuleBitcodeWriter::writeDISubrange(const DISubrange *N,
1649                                           SmallVectorImpl<uint64_t> &Record,
1650                                           unsigned Abbrev) {
1651   const uint64_t Version = 2 << 1;
1652   Record.push_back((uint64_t)N->isDistinct() | Version);
1653   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1654   Record.push_back(VE.getMetadataOrNullID(N->getRawLowerBound()));
1655   Record.push_back(VE.getMetadataOrNullID(N->getRawUpperBound()));
1656   Record.push_back(VE.getMetadataOrNullID(N->getRawStride()));
1657 
1658   Stream.EmitRecord(bitc::METADATA_SUBRANGE, Record, Abbrev);
1659   Record.clear();
1660 }
1661 
1662 void ModuleBitcodeWriter::writeDIGenericSubrange(
1663     const DIGenericSubrange *N, SmallVectorImpl<uint64_t> &Record,
1664     unsigned Abbrev) {
1665   Record.push_back((uint64_t)N->isDistinct());
1666   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1667   Record.push_back(VE.getMetadataOrNullID(N->getRawLowerBound()));
1668   Record.push_back(VE.getMetadataOrNullID(N->getRawUpperBound()));
1669   Record.push_back(VE.getMetadataOrNullID(N->getRawStride()));
1670 
1671   Stream.EmitRecord(bitc::METADATA_GENERIC_SUBRANGE, Record, Abbrev);
1672   Record.clear();
1673 }
1674 
1675 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
1676   if ((int64_t)V >= 0)
1677     Vals.push_back(V << 1);
1678   else
1679     Vals.push_back((-V << 1) | 1);
1680 }
1681 
1682 static void emitWideAPInt(SmallVectorImpl<uint64_t> &Vals, const APInt &A) {
1683   // We have an arbitrary precision integer value to write whose
1684   // bit width is > 64. However, in canonical unsigned integer
1685   // format it is likely that the high bits are going to be zero.
1686   // So, we only write the number of active words.
1687   unsigned NumWords = A.getActiveWords();
1688   const uint64_t *RawData = A.getRawData();
1689   for (unsigned i = 0; i < NumWords; i++)
1690     emitSignedInt64(Vals, RawData[i]);
1691 }
1692 
1693 void ModuleBitcodeWriter::writeDIEnumerator(const DIEnumerator *N,
1694                                             SmallVectorImpl<uint64_t> &Record,
1695                                             unsigned Abbrev) {
1696   const uint64_t IsBigInt = 1 << 2;
1697   Record.push_back(IsBigInt | (N->isUnsigned() << 1) | N->isDistinct());
1698   Record.push_back(N->getValue().getBitWidth());
1699   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1700   emitWideAPInt(Record, N->getValue());
1701 
1702   Stream.EmitRecord(bitc::METADATA_ENUMERATOR, Record, Abbrev);
1703   Record.clear();
1704 }
1705 
1706 void ModuleBitcodeWriter::writeDIBasicType(const DIBasicType *N,
1707                                            SmallVectorImpl<uint64_t> &Record,
1708                                            unsigned Abbrev) {
1709   Record.push_back(N->isDistinct());
1710   Record.push_back(N->getTag());
1711   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1712   Record.push_back(N->getSizeInBits());
1713   Record.push_back(N->getAlignInBits());
1714   Record.push_back(N->getEncoding());
1715   Record.push_back(N->getFlags());
1716 
1717   Stream.EmitRecord(bitc::METADATA_BASIC_TYPE, Record, Abbrev);
1718   Record.clear();
1719 }
1720 
1721 void ModuleBitcodeWriter::writeDIStringType(const DIStringType *N,
1722                                             SmallVectorImpl<uint64_t> &Record,
1723                                             unsigned Abbrev) {
1724   Record.push_back(N->isDistinct());
1725   Record.push_back(N->getTag());
1726   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1727   Record.push_back(VE.getMetadataOrNullID(N->getStringLength()));
1728   Record.push_back(VE.getMetadataOrNullID(N->getStringLengthExp()));
1729   Record.push_back(VE.getMetadataOrNullID(N->getStringLocationExp()));
1730   Record.push_back(N->getSizeInBits());
1731   Record.push_back(N->getAlignInBits());
1732   Record.push_back(N->getEncoding());
1733 
1734   Stream.EmitRecord(bitc::METADATA_STRING_TYPE, Record, Abbrev);
1735   Record.clear();
1736 }
1737 
1738 void ModuleBitcodeWriter::writeDIDerivedType(const DIDerivedType *N,
1739                                              SmallVectorImpl<uint64_t> &Record,
1740                                              unsigned Abbrev) {
1741   Record.push_back(N->isDistinct());
1742   Record.push_back(N->getTag());
1743   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1744   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1745   Record.push_back(N->getLine());
1746   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1747   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1748   Record.push_back(N->getSizeInBits());
1749   Record.push_back(N->getAlignInBits());
1750   Record.push_back(N->getOffsetInBits());
1751   Record.push_back(N->getFlags());
1752   Record.push_back(VE.getMetadataOrNullID(N->getExtraData()));
1753 
1754   // DWARF address space is encoded as N->getDWARFAddressSpace() + 1. 0 means
1755   // that there is no DWARF address space associated with DIDerivedType.
1756   if (const auto &DWARFAddressSpace = N->getDWARFAddressSpace())
1757     Record.push_back(*DWARFAddressSpace + 1);
1758   else
1759     Record.push_back(0);
1760 
1761   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1762 
1763   Stream.EmitRecord(bitc::METADATA_DERIVED_TYPE, Record, Abbrev);
1764   Record.clear();
1765 }
1766 
1767 void ModuleBitcodeWriter::writeDICompositeType(
1768     const DICompositeType *N, SmallVectorImpl<uint64_t> &Record,
1769     unsigned Abbrev) {
1770   const unsigned IsNotUsedInOldTypeRef = 0x2;
1771   Record.push_back(IsNotUsedInOldTypeRef | (unsigned)N->isDistinct());
1772   Record.push_back(N->getTag());
1773   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1774   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1775   Record.push_back(N->getLine());
1776   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1777   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1778   Record.push_back(N->getSizeInBits());
1779   Record.push_back(N->getAlignInBits());
1780   Record.push_back(N->getOffsetInBits());
1781   Record.push_back(N->getFlags());
1782   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1783   Record.push_back(N->getRuntimeLang());
1784   Record.push_back(VE.getMetadataOrNullID(N->getVTableHolder()));
1785   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1786   Record.push_back(VE.getMetadataOrNullID(N->getRawIdentifier()));
1787   Record.push_back(VE.getMetadataOrNullID(N->getDiscriminator()));
1788   Record.push_back(VE.getMetadataOrNullID(N->getRawDataLocation()));
1789   Record.push_back(VE.getMetadataOrNullID(N->getRawAssociated()));
1790   Record.push_back(VE.getMetadataOrNullID(N->getRawAllocated()));
1791   Record.push_back(VE.getMetadataOrNullID(N->getRawRank()));
1792   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1793 
1794   Stream.EmitRecord(bitc::METADATA_COMPOSITE_TYPE, Record, Abbrev);
1795   Record.clear();
1796 }
1797 
1798 void ModuleBitcodeWriter::writeDISubroutineType(
1799     const DISubroutineType *N, SmallVectorImpl<uint64_t> &Record,
1800     unsigned Abbrev) {
1801   const unsigned HasNoOldTypeRefs = 0x2;
1802   Record.push_back(HasNoOldTypeRefs | (unsigned)N->isDistinct());
1803   Record.push_back(N->getFlags());
1804   Record.push_back(VE.getMetadataOrNullID(N->getTypeArray().get()));
1805   Record.push_back(N->getCC());
1806 
1807   Stream.EmitRecord(bitc::METADATA_SUBROUTINE_TYPE, Record, Abbrev);
1808   Record.clear();
1809 }
1810 
1811 void ModuleBitcodeWriter::writeDIFile(const DIFile *N,
1812                                       SmallVectorImpl<uint64_t> &Record,
1813                                       unsigned Abbrev) {
1814   Record.push_back(N->isDistinct());
1815   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
1816   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
1817   if (N->getRawChecksum()) {
1818     Record.push_back(N->getRawChecksum()->Kind);
1819     Record.push_back(VE.getMetadataOrNullID(N->getRawChecksum()->Value));
1820   } else {
1821     // Maintain backwards compatibility with the old internal representation of
1822     // CSK_None in ChecksumKind by writing nulls here when Checksum is None.
1823     Record.push_back(0);
1824     Record.push_back(VE.getMetadataOrNullID(nullptr));
1825   }
1826   auto Source = N->getRawSource();
1827   if (Source)
1828     Record.push_back(VE.getMetadataOrNullID(Source));
1829 
1830   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
1831   Record.clear();
1832 }
1833 
1834 void ModuleBitcodeWriter::writeDICompileUnit(const DICompileUnit *N,
1835                                              SmallVectorImpl<uint64_t> &Record,
1836                                              unsigned Abbrev) {
1837   assert(N->isDistinct() && "Expected distinct compile units");
1838   Record.push_back(/* IsDistinct */ true);
1839   Record.push_back(N->getSourceLanguage());
1840   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1841   Record.push_back(VE.getMetadataOrNullID(N->getRawProducer()));
1842   Record.push_back(N->isOptimized());
1843   Record.push_back(VE.getMetadataOrNullID(N->getRawFlags()));
1844   Record.push_back(N->getRuntimeVersion());
1845   Record.push_back(VE.getMetadataOrNullID(N->getRawSplitDebugFilename()));
1846   Record.push_back(N->getEmissionKind());
1847   Record.push_back(VE.getMetadataOrNullID(N->getEnumTypes().get()));
1848   Record.push_back(VE.getMetadataOrNullID(N->getRetainedTypes().get()));
1849   Record.push_back(/* subprograms */ 0);
1850   Record.push_back(VE.getMetadataOrNullID(N->getGlobalVariables().get()));
1851   Record.push_back(VE.getMetadataOrNullID(N->getImportedEntities().get()));
1852   Record.push_back(N->getDWOId());
1853   Record.push_back(VE.getMetadataOrNullID(N->getMacros().get()));
1854   Record.push_back(N->getSplitDebugInlining());
1855   Record.push_back(N->getDebugInfoForProfiling());
1856   Record.push_back((unsigned)N->getNameTableKind());
1857   Record.push_back(N->getRangesBaseAddress());
1858   Record.push_back(VE.getMetadataOrNullID(N->getRawSysRoot()));
1859   Record.push_back(VE.getMetadataOrNullID(N->getRawSDK()));
1860 
1861   Stream.EmitRecord(bitc::METADATA_COMPILE_UNIT, Record, Abbrev);
1862   Record.clear();
1863 }
1864 
1865 void ModuleBitcodeWriter::writeDISubprogram(const DISubprogram *N,
1866                                             SmallVectorImpl<uint64_t> &Record,
1867                                             unsigned Abbrev) {
1868   const uint64_t HasUnitFlag = 1 << 1;
1869   const uint64_t HasSPFlagsFlag = 1 << 2;
1870   Record.push_back(uint64_t(N->isDistinct()) | HasUnitFlag | HasSPFlagsFlag);
1871   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1872   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1873   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1874   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1875   Record.push_back(N->getLine());
1876   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1877   Record.push_back(N->getScopeLine());
1878   Record.push_back(VE.getMetadataOrNullID(N->getContainingType()));
1879   Record.push_back(N->getSPFlags());
1880   Record.push_back(N->getVirtualIndex());
1881   Record.push_back(N->getFlags());
1882   Record.push_back(VE.getMetadataOrNullID(N->getRawUnit()));
1883   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1884   Record.push_back(VE.getMetadataOrNullID(N->getDeclaration()));
1885   Record.push_back(VE.getMetadataOrNullID(N->getRetainedNodes().get()));
1886   Record.push_back(N->getThisAdjustment());
1887   Record.push_back(VE.getMetadataOrNullID(N->getThrownTypes().get()));
1888   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1889   Record.push_back(VE.getMetadataOrNullID(N->getRawTargetFuncName()));
1890 
1891   Stream.EmitRecord(bitc::METADATA_SUBPROGRAM, Record, Abbrev);
1892   Record.clear();
1893 }
1894 
1895 void ModuleBitcodeWriter::writeDILexicalBlock(const DILexicalBlock *N,
1896                                               SmallVectorImpl<uint64_t> &Record,
1897                                               unsigned Abbrev) {
1898   Record.push_back(N->isDistinct());
1899   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1900   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1901   Record.push_back(N->getLine());
1902   Record.push_back(N->getColumn());
1903 
1904   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK, Record, Abbrev);
1905   Record.clear();
1906 }
1907 
1908 void ModuleBitcodeWriter::writeDILexicalBlockFile(
1909     const DILexicalBlockFile *N, SmallVectorImpl<uint64_t> &Record,
1910     unsigned Abbrev) {
1911   Record.push_back(N->isDistinct());
1912   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1913   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1914   Record.push_back(N->getDiscriminator());
1915 
1916   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK_FILE, Record, Abbrev);
1917   Record.clear();
1918 }
1919 
1920 void ModuleBitcodeWriter::writeDICommonBlock(const DICommonBlock *N,
1921                                              SmallVectorImpl<uint64_t> &Record,
1922                                              unsigned Abbrev) {
1923   Record.push_back(N->isDistinct());
1924   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1925   Record.push_back(VE.getMetadataOrNullID(N->getDecl()));
1926   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1927   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1928   Record.push_back(N->getLineNo());
1929 
1930   Stream.EmitRecord(bitc::METADATA_COMMON_BLOCK, Record, Abbrev);
1931   Record.clear();
1932 }
1933 
1934 void ModuleBitcodeWriter::writeDINamespace(const DINamespace *N,
1935                                            SmallVectorImpl<uint64_t> &Record,
1936                                            unsigned Abbrev) {
1937   Record.push_back(N->isDistinct() | N->getExportSymbols() << 1);
1938   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1939   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1940 
1941   Stream.EmitRecord(bitc::METADATA_NAMESPACE, Record, Abbrev);
1942   Record.clear();
1943 }
1944 
1945 void ModuleBitcodeWriter::writeDIMacro(const DIMacro *N,
1946                                        SmallVectorImpl<uint64_t> &Record,
1947                                        unsigned Abbrev) {
1948   Record.push_back(N->isDistinct());
1949   Record.push_back(N->getMacinfoType());
1950   Record.push_back(N->getLine());
1951   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1952   Record.push_back(VE.getMetadataOrNullID(N->getRawValue()));
1953 
1954   Stream.EmitRecord(bitc::METADATA_MACRO, Record, Abbrev);
1955   Record.clear();
1956 }
1957 
1958 void ModuleBitcodeWriter::writeDIMacroFile(const DIMacroFile *N,
1959                                            SmallVectorImpl<uint64_t> &Record,
1960                                            unsigned Abbrev) {
1961   Record.push_back(N->isDistinct());
1962   Record.push_back(N->getMacinfoType());
1963   Record.push_back(N->getLine());
1964   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1965   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1966 
1967   Stream.EmitRecord(bitc::METADATA_MACRO_FILE, Record, Abbrev);
1968   Record.clear();
1969 }
1970 
1971 void ModuleBitcodeWriter::writeDIArgList(const DIArgList *N,
1972                                          SmallVectorImpl<uint64_t> &Record,
1973                                          unsigned Abbrev) {
1974   Record.reserve(N->getArgs().size());
1975   for (ValueAsMetadata *MD : N->getArgs())
1976     Record.push_back(VE.getMetadataID(MD));
1977 
1978   Stream.EmitRecord(bitc::METADATA_ARG_LIST, Record, Abbrev);
1979   Record.clear();
1980 }
1981 
1982 void ModuleBitcodeWriter::writeDIModule(const DIModule *N,
1983                                         SmallVectorImpl<uint64_t> &Record,
1984                                         unsigned Abbrev) {
1985   Record.push_back(N->isDistinct());
1986   for (auto &I : N->operands())
1987     Record.push_back(VE.getMetadataOrNullID(I));
1988   Record.push_back(N->getLineNo());
1989   Record.push_back(N->getIsDecl());
1990 
1991   Stream.EmitRecord(bitc::METADATA_MODULE, Record, Abbrev);
1992   Record.clear();
1993 }
1994 
1995 void ModuleBitcodeWriter::writeDIAssignID(const DIAssignID *N,
1996                                           SmallVectorImpl<uint64_t> &Record,
1997                                           unsigned Abbrev) {
1998   // There are no arguments for this metadata type.
1999   Record.push_back(N->isDistinct());
2000   Stream.EmitRecord(bitc::METADATA_ASSIGN_ID, Record, Abbrev);
2001   Record.clear();
2002 }
2003 
2004 void ModuleBitcodeWriter::writeDITemplateTypeParameter(
2005     const DITemplateTypeParameter *N, SmallVectorImpl<uint64_t> &Record,
2006     unsigned Abbrev) {
2007   Record.push_back(N->isDistinct());
2008   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2009   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2010   Record.push_back(N->isDefault());
2011 
2012   Stream.EmitRecord(bitc::METADATA_TEMPLATE_TYPE, Record, Abbrev);
2013   Record.clear();
2014 }
2015 
2016 void ModuleBitcodeWriter::writeDITemplateValueParameter(
2017     const DITemplateValueParameter *N, SmallVectorImpl<uint64_t> &Record,
2018     unsigned Abbrev) {
2019   Record.push_back(N->isDistinct());
2020   Record.push_back(N->getTag());
2021   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2022   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2023   Record.push_back(N->isDefault());
2024   Record.push_back(VE.getMetadataOrNullID(N->getValue()));
2025 
2026   Stream.EmitRecord(bitc::METADATA_TEMPLATE_VALUE, Record, Abbrev);
2027   Record.clear();
2028 }
2029 
2030 void ModuleBitcodeWriter::writeDIGlobalVariable(
2031     const DIGlobalVariable *N, SmallVectorImpl<uint64_t> &Record,
2032     unsigned Abbrev) {
2033   const uint64_t Version = 2 << 1;
2034   Record.push_back((uint64_t)N->isDistinct() | Version);
2035   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2036   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2037   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
2038   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2039   Record.push_back(N->getLine());
2040   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2041   Record.push_back(N->isLocalToUnit());
2042   Record.push_back(N->isDefinition());
2043   Record.push_back(VE.getMetadataOrNullID(N->getStaticDataMemberDeclaration()));
2044   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams()));
2045   Record.push_back(N->getAlignInBits());
2046   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
2047 
2048   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR, Record, Abbrev);
2049   Record.clear();
2050 }
2051 
2052 void ModuleBitcodeWriter::writeDILocalVariable(
2053     const DILocalVariable *N, SmallVectorImpl<uint64_t> &Record,
2054     unsigned Abbrev) {
2055   // In order to support all possible bitcode formats in BitcodeReader we need
2056   // to distinguish the following cases:
2057   // 1) Record has no artificial tag (Record[1]),
2058   //   has no obsolete inlinedAt field (Record[9]).
2059   //   In this case Record size will be 8, HasAlignment flag is false.
2060   // 2) Record has artificial tag (Record[1]),
2061   //   has no obsolete inlignedAt field (Record[9]).
2062   //   In this case Record size will be 9, HasAlignment flag is false.
2063   // 3) Record has both artificial tag (Record[1]) and
2064   //   obsolete inlignedAt field (Record[9]).
2065   //   In this case Record size will be 10, HasAlignment flag is false.
2066   // 4) Record has neither artificial tag, nor inlignedAt field, but
2067   //   HasAlignment flag is true and Record[8] contains alignment value.
2068   const uint64_t HasAlignmentFlag = 1 << 1;
2069   Record.push_back((uint64_t)N->isDistinct() | HasAlignmentFlag);
2070   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2071   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2072   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2073   Record.push_back(N->getLine());
2074   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2075   Record.push_back(N->getArg());
2076   Record.push_back(N->getFlags());
2077   Record.push_back(N->getAlignInBits());
2078   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
2079 
2080   Stream.EmitRecord(bitc::METADATA_LOCAL_VAR, Record, Abbrev);
2081   Record.clear();
2082 }
2083 
2084 void ModuleBitcodeWriter::writeDILabel(
2085     const DILabel *N, SmallVectorImpl<uint64_t> &Record,
2086     unsigned Abbrev) {
2087   Record.push_back((uint64_t)N->isDistinct());
2088   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2089   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2090   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2091   Record.push_back(N->getLine());
2092 
2093   Stream.EmitRecord(bitc::METADATA_LABEL, Record, Abbrev);
2094   Record.clear();
2095 }
2096 
2097 void ModuleBitcodeWriter::writeDIExpression(const DIExpression *N,
2098                                             SmallVectorImpl<uint64_t> &Record,
2099                                             unsigned Abbrev) {
2100   Record.reserve(N->getElements().size() + 1);
2101   const uint64_t Version = 3 << 1;
2102   Record.push_back((uint64_t)N->isDistinct() | Version);
2103   Record.append(N->elements_begin(), N->elements_end());
2104 
2105   Stream.EmitRecord(bitc::METADATA_EXPRESSION, Record, Abbrev);
2106   Record.clear();
2107 }
2108 
2109 void ModuleBitcodeWriter::writeDIGlobalVariableExpression(
2110     const DIGlobalVariableExpression *N, SmallVectorImpl<uint64_t> &Record,
2111     unsigned Abbrev) {
2112   Record.push_back(N->isDistinct());
2113   Record.push_back(VE.getMetadataOrNullID(N->getVariable()));
2114   Record.push_back(VE.getMetadataOrNullID(N->getExpression()));
2115 
2116   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR_EXPR, Record, Abbrev);
2117   Record.clear();
2118 }
2119 
2120 void ModuleBitcodeWriter::writeDIObjCProperty(const DIObjCProperty *N,
2121                                               SmallVectorImpl<uint64_t> &Record,
2122                                               unsigned Abbrev) {
2123   Record.push_back(N->isDistinct());
2124   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2125   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2126   Record.push_back(N->getLine());
2127   Record.push_back(VE.getMetadataOrNullID(N->getRawSetterName()));
2128   Record.push_back(VE.getMetadataOrNullID(N->getRawGetterName()));
2129   Record.push_back(N->getAttributes());
2130   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2131 
2132   Stream.EmitRecord(bitc::METADATA_OBJC_PROPERTY, Record, Abbrev);
2133   Record.clear();
2134 }
2135 
2136 void ModuleBitcodeWriter::writeDIImportedEntity(
2137     const DIImportedEntity *N, SmallVectorImpl<uint64_t> &Record,
2138     unsigned Abbrev) {
2139   Record.push_back(N->isDistinct());
2140   Record.push_back(N->getTag());
2141   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2142   Record.push_back(VE.getMetadataOrNullID(N->getEntity()));
2143   Record.push_back(N->getLine());
2144   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2145   Record.push_back(VE.getMetadataOrNullID(N->getRawFile()));
2146   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
2147 
2148   Stream.EmitRecord(bitc::METADATA_IMPORTED_ENTITY, Record, Abbrev);
2149   Record.clear();
2150 }
2151 
2152 unsigned ModuleBitcodeWriter::createNamedMetadataAbbrev() {
2153   auto Abbv = std::make_shared<BitCodeAbbrev>();
2154   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
2155   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2156   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2157   return Stream.EmitAbbrev(std::move(Abbv));
2158 }
2159 
2160 void ModuleBitcodeWriter::writeNamedMetadata(
2161     SmallVectorImpl<uint64_t> &Record) {
2162   if (M.named_metadata_empty())
2163     return;
2164 
2165   unsigned Abbrev = createNamedMetadataAbbrev();
2166   for (const NamedMDNode &NMD : M.named_metadata()) {
2167     // Write name.
2168     StringRef Str = NMD.getName();
2169     Record.append(Str.bytes_begin(), Str.bytes_end());
2170     Stream.EmitRecord(bitc::METADATA_NAME, Record, Abbrev);
2171     Record.clear();
2172 
2173     // Write named metadata operands.
2174     for (const MDNode *N : NMD.operands())
2175       Record.push_back(VE.getMetadataID(N));
2176     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
2177     Record.clear();
2178   }
2179 }
2180 
2181 unsigned ModuleBitcodeWriter::createMetadataStringsAbbrev() {
2182   auto Abbv = std::make_shared<BitCodeAbbrev>();
2183   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRINGS));
2184   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // # of strings
2185   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // offset to chars
2186   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
2187   return Stream.EmitAbbrev(std::move(Abbv));
2188 }
2189 
2190 /// Write out a record for MDString.
2191 ///
2192 /// All the metadata strings in a metadata block are emitted in a single
2193 /// record.  The sizes and strings themselves are shoved into a blob.
2194 void ModuleBitcodeWriter::writeMetadataStrings(
2195     ArrayRef<const Metadata *> Strings, SmallVectorImpl<uint64_t> &Record) {
2196   if (Strings.empty())
2197     return;
2198 
2199   // Start the record with the number of strings.
2200   Record.push_back(bitc::METADATA_STRINGS);
2201   Record.push_back(Strings.size());
2202 
2203   // Emit the sizes of the strings in the blob.
2204   SmallString<256> Blob;
2205   {
2206     BitstreamWriter W(Blob);
2207     for (const Metadata *MD : Strings)
2208       W.EmitVBR(cast<MDString>(MD)->getLength(), 6);
2209     W.FlushToWord();
2210   }
2211 
2212   // Add the offset to the strings to the record.
2213   Record.push_back(Blob.size());
2214 
2215   // Add the strings to the blob.
2216   for (const Metadata *MD : Strings)
2217     Blob.append(cast<MDString>(MD)->getString());
2218 
2219   // Emit the final record.
2220   Stream.EmitRecordWithBlob(createMetadataStringsAbbrev(), Record, Blob);
2221   Record.clear();
2222 }
2223 
2224 // Generates an enum to use as an index in the Abbrev array of Metadata record.
2225 enum MetadataAbbrev : unsigned {
2226 #define HANDLE_MDNODE_LEAF(CLASS) CLASS##AbbrevID,
2227 #include "llvm/IR/Metadata.def"
2228   LastPlusOne
2229 };
2230 
2231 void ModuleBitcodeWriter::writeMetadataRecords(
2232     ArrayRef<const Metadata *> MDs, SmallVectorImpl<uint64_t> &Record,
2233     std::vector<unsigned> *MDAbbrevs, std::vector<uint64_t> *IndexPos) {
2234   if (MDs.empty())
2235     return;
2236 
2237   // Initialize MDNode abbreviations.
2238 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
2239 #include "llvm/IR/Metadata.def"
2240 
2241   for (const Metadata *MD : MDs) {
2242     if (IndexPos)
2243       IndexPos->push_back(Stream.GetCurrentBitNo());
2244     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
2245       assert(N->isResolved() && "Expected forward references to be resolved");
2246 
2247       switch (N->getMetadataID()) {
2248       default:
2249         llvm_unreachable("Invalid MDNode subclass");
2250 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
2251   case Metadata::CLASS##Kind:                                                  \
2252     if (MDAbbrevs)                                                             \
2253       write##CLASS(cast<CLASS>(N), Record,                                     \
2254                    (*MDAbbrevs)[MetadataAbbrev::CLASS##AbbrevID]);             \
2255     else                                                                       \
2256       write##CLASS(cast<CLASS>(N), Record, CLASS##Abbrev);                     \
2257     continue;
2258 #include "llvm/IR/Metadata.def"
2259       }
2260     }
2261     writeValueAsMetadata(cast<ValueAsMetadata>(MD), Record);
2262   }
2263 }
2264 
2265 void ModuleBitcodeWriter::writeModuleMetadata() {
2266   if (!VE.hasMDs() && M.named_metadata_empty())
2267     return;
2268 
2269   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 4);
2270   SmallVector<uint64_t, 64> Record;
2271 
2272   // Emit all abbrevs upfront, so that the reader can jump in the middle of the
2273   // block and load any metadata.
2274   std::vector<unsigned> MDAbbrevs;
2275 
2276   MDAbbrevs.resize(MetadataAbbrev::LastPlusOne);
2277   MDAbbrevs[MetadataAbbrev::DILocationAbbrevID] = createDILocationAbbrev();
2278   MDAbbrevs[MetadataAbbrev::GenericDINodeAbbrevID] =
2279       createGenericDINodeAbbrev();
2280 
2281   auto Abbv = std::make_shared<BitCodeAbbrev>();
2282   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX_OFFSET));
2283   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2284   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2285   unsigned OffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2286 
2287   Abbv = std::make_shared<BitCodeAbbrev>();
2288   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX));
2289   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2290   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2291   unsigned IndexAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2292 
2293   // Emit MDStrings together upfront.
2294   writeMetadataStrings(VE.getMDStrings(), Record);
2295 
2296   // We only emit an index for the metadata record if we have more than a given
2297   // (naive) threshold of metadatas, otherwise it is not worth it.
2298   if (VE.getNonMDStrings().size() > IndexThreshold) {
2299     // Write a placeholder value in for the offset of the metadata index,
2300     // which is written after the records, so that it can include
2301     // the offset of each entry. The placeholder offset will be
2302     // updated after all records are emitted.
2303     uint64_t Vals[] = {0, 0};
2304     Stream.EmitRecord(bitc::METADATA_INDEX_OFFSET, Vals, OffsetAbbrev);
2305   }
2306 
2307   // Compute and save the bit offset to the current position, which will be
2308   // patched when we emit the index later. We can simply subtract the 64-bit
2309   // fixed size from the current bit number to get the location to backpatch.
2310   uint64_t IndexOffsetRecordBitPos = Stream.GetCurrentBitNo();
2311 
2312   // This index will contain the bitpos for each individual record.
2313   std::vector<uint64_t> IndexPos;
2314   IndexPos.reserve(VE.getNonMDStrings().size());
2315 
2316   // Write all the records
2317   writeMetadataRecords(VE.getNonMDStrings(), Record, &MDAbbrevs, &IndexPos);
2318 
2319   if (VE.getNonMDStrings().size() > IndexThreshold) {
2320     // Now that we have emitted all the records we will emit the index. But
2321     // first
2322     // backpatch the forward reference so that the reader can skip the records
2323     // efficiently.
2324     Stream.BackpatchWord64(IndexOffsetRecordBitPos - 64,
2325                            Stream.GetCurrentBitNo() - IndexOffsetRecordBitPos);
2326 
2327     // Delta encode the index.
2328     uint64_t PreviousValue = IndexOffsetRecordBitPos;
2329     for (auto &Elt : IndexPos) {
2330       auto EltDelta = Elt - PreviousValue;
2331       PreviousValue = Elt;
2332       Elt = EltDelta;
2333     }
2334     // Emit the index record.
2335     Stream.EmitRecord(bitc::METADATA_INDEX, IndexPos, IndexAbbrev);
2336     IndexPos.clear();
2337   }
2338 
2339   // Write the named metadata now.
2340   writeNamedMetadata(Record);
2341 
2342   auto AddDeclAttachedMetadata = [&](const GlobalObject &GO) {
2343     SmallVector<uint64_t, 4> Record;
2344     Record.push_back(VE.getValueID(&GO));
2345     pushGlobalMetadataAttachment(Record, GO);
2346     Stream.EmitRecord(bitc::METADATA_GLOBAL_DECL_ATTACHMENT, Record);
2347   };
2348   for (const Function &F : M)
2349     if (F.isDeclaration() && F.hasMetadata())
2350       AddDeclAttachedMetadata(F);
2351   // FIXME: Only store metadata for declarations here, and move data for global
2352   // variable definitions to a separate block (PR28134).
2353   for (const GlobalVariable &GV : M.globals())
2354     if (GV.hasMetadata())
2355       AddDeclAttachedMetadata(GV);
2356 
2357   Stream.ExitBlock();
2358 }
2359 
2360 void ModuleBitcodeWriter::writeFunctionMetadata(const Function &F) {
2361   if (!VE.hasMDs())
2362     return;
2363 
2364   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
2365   SmallVector<uint64_t, 64> Record;
2366   writeMetadataStrings(VE.getMDStrings(), Record);
2367   writeMetadataRecords(VE.getNonMDStrings(), Record);
2368   Stream.ExitBlock();
2369 }
2370 
2371 void ModuleBitcodeWriter::pushGlobalMetadataAttachment(
2372     SmallVectorImpl<uint64_t> &Record, const GlobalObject &GO) {
2373   // [n x [id, mdnode]]
2374   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2375   GO.getAllMetadata(MDs);
2376   for (const auto &I : MDs) {
2377     Record.push_back(I.first);
2378     Record.push_back(VE.getMetadataID(I.second));
2379   }
2380 }
2381 
2382 void ModuleBitcodeWriter::writeFunctionMetadataAttachment(const Function &F) {
2383   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
2384 
2385   SmallVector<uint64_t, 64> Record;
2386 
2387   if (F.hasMetadata()) {
2388     pushGlobalMetadataAttachment(Record, F);
2389     Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2390     Record.clear();
2391   }
2392 
2393   // Write metadata attachments
2394   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
2395   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2396   for (const BasicBlock &BB : F)
2397     for (const Instruction &I : BB) {
2398       MDs.clear();
2399       I.getAllMetadataOtherThanDebugLoc(MDs);
2400 
2401       // If no metadata, ignore instruction.
2402       if (MDs.empty()) continue;
2403 
2404       Record.push_back(VE.getInstructionID(&I));
2405 
2406       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
2407         Record.push_back(MDs[i].first);
2408         Record.push_back(VE.getMetadataID(MDs[i].second));
2409       }
2410       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2411       Record.clear();
2412     }
2413 
2414   Stream.ExitBlock();
2415 }
2416 
2417 void ModuleBitcodeWriter::writeModuleMetadataKinds() {
2418   SmallVector<uint64_t, 64> Record;
2419 
2420   // Write metadata kinds
2421   // METADATA_KIND - [n x [id, name]]
2422   SmallVector<StringRef, 8> Names;
2423   M.getMDKindNames(Names);
2424 
2425   if (Names.empty()) return;
2426 
2427   Stream.EnterSubblock(bitc::METADATA_KIND_BLOCK_ID, 3);
2428 
2429   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
2430     Record.push_back(MDKindID);
2431     StringRef KName = Names[MDKindID];
2432     Record.append(KName.begin(), KName.end());
2433 
2434     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
2435     Record.clear();
2436   }
2437 
2438   Stream.ExitBlock();
2439 }
2440 
2441 void ModuleBitcodeWriter::writeOperandBundleTags() {
2442   // Write metadata kinds
2443   //
2444   // OPERAND_BUNDLE_TAGS_BLOCK_ID : N x OPERAND_BUNDLE_TAG
2445   //
2446   // OPERAND_BUNDLE_TAG - [strchr x N]
2447 
2448   SmallVector<StringRef, 8> Tags;
2449   M.getOperandBundleTags(Tags);
2450 
2451   if (Tags.empty())
2452     return;
2453 
2454   Stream.EnterSubblock(bitc::OPERAND_BUNDLE_TAGS_BLOCK_ID, 3);
2455 
2456   SmallVector<uint64_t, 64> Record;
2457 
2458   for (auto Tag : Tags) {
2459     Record.append(Tag.begin(), Tag.end());
2460 
2461     Stream.EmitRecord(bitc::OPERAND_BUNDLE_TAG, Record, 0);
2462     Record.clear();
2463   }
2464 
2465   Stream.ExitBlock();
2466 }
2467 
2468 void ModuleBitcodeWriter::writeSyncScopeNames() {
2469   SmallVector<StringRef, 8> SSNs;
2470   M.getContext().getSyncScopeNames(SSNs);
2471   if (SSNs.empty())
2472     return;
2473 
2474   Stream.EnterSubblock(bitc::SYNC_SCOPE_NAMES_BLOCK_ID, 2);
2475 
2476   SmallVector<uint64_t, 64> Record;
2477   for (auto SSN : SSNs) {
2478     Record.append(SSN.begin(), SSN.end());
2479     Stream.EmitRecord(bitc::SYNC_SCOPE_NAME, Record, 0);
2480     Record.clear();
2481   }
2482 
2483   Stream.ExitBlock();
2484 }
2485 
2486 void ModuleBitcodeWriter::writeConstants(unsigned FirstVal, unsigned LastVal,
2487                                          bool isGlobal) {
2488   if (FirstVal == LastVal) return;
2489 
2490   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
2491 
2492   unsigned AggregateAbbrev = 0;
2493   unsigned String8Abbrev = 0;
2494   unsigned CString7Abbrev = 0;
2495   unsigned CString6Abbrev = 0;
2496   // If this is a constant pool for the module, emit module-specific abbrevs.
2497   if (isGlobal) {
2498     // Abbrev for CST_CODE_AGGREGATE.
2499     auto Abbv = std::make_shared<BitCodeAbbrev>();
2500     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
2501     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2502     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
2503     AggregateAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2504 
2505     // Abbrev for CST_CODE_STRING.
2506     Abbv = std::make_shared<BitCodeAbbrev>();
2507     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
2508     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2509     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2510     String8Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2511     // Abbrev for CST_CODE_CSTRING.
2512     Abbv = std::make_shared<BitCodeAbbrev>();
2513     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2514     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2515     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2516     CString7Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2517     // Abbrev for CST_CODE_CSTRING.
2518     Abbv = std::make_shared<BitCodeAbbrev>();
2519     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2520     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2521     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2522     CString6Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2523   }
2524 
2525   SmallVector<uint64_t, 64> Record;
2526 
2527   const ValueEnumerator::ValueList &Vals = VE.getValues();
2528   Type *LastTy = nullptr;
2529   for (unsigned i = FirstVal; i != LastVal; ++i) {
2530     const Value *V = Vals[i].first;
2531     // If we need to switch types, do so now.
2532     if (V->getType() != LastTy) {
2533       LastTy = V->getType();
2534       Record.push_back(VE.getTypeID(LastTy));
2535       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
2536                         CONSTANTS_SETTYPE_ABBREV);
2537       Record.clear();
2538     }
2539 
2540     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
2541       Record.push_back(VE.getTypeID(IA->getFunctionType()));
2542       Record.push_back(
2543           unsigned(IA->hasSideEffects()) | unsigned(IA->isAlignStack()) << 1 |
2544           unsigned(IA->getDialect() & 1) << 2 | unsigned(IA->canThrow()) << 3);
2545 
2546       // Add the asm string.
2547       const std::string &AsmStr = IA->getAsmString();
2548       Record.push_back(AsmStr.size());
2549       Record.append(AsmStr.begin(), AsmStr.end());
2550 
2551       // Add the constraint string.
2552       const std::string &ConstraintStr = IA->getConstraintString();
2553       Record.push_back(ConstraintStr.size());
2554       Record.append(ConstraintStr.begin(), ConstraintStr.end());
2555       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
2556       Record.clear();
2557       continue;
2558     }
2559     const Constant *C = cast<Constant>(V);
2560     unsigned Code = -1U;
2561     unsigned AbbrevToUse = 0;
2562     if (C->isNullValue()) {
2563       Code = bitc::CST_CODE_NULL;
2564     } else if (isa<PoisonValue>(C)) {
2565       Code = bitc::CST_CODE_POISON;
2566     } else if (isa<UndefValue>(C)) {
2567       Code = bitc::CST_CODE_UNDEF;
2568     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
2569       if (IV->getBitWidth() <= 64) {
2570         uint64_t V = IV->getSExtValue();
2571         emitSignedInt64(Record, V);
2572         Code = bitc::CST_CODE_INTEGER;
2573         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
2574       } else {                             // Wide integers, > 64 bits in size.
2575         emitWideAPInt(Record, IV->getValue());
2576         Code = bitc::CST_CODE_WIDE_INTEGER;
2577       }
2578     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
2579       Code = bitc::CST_CODE_FLOAT;
2580       Type *Ty = CFP->getType();
2581       if (Ty->isHalfTy() || Ty->isBFloatTy() || Ty->isFloatTy() ||
2582           Ty->isDoubleTy()) {
2583         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
2584       } else if (Ty->isX86_FP80Ty()) {
2585         // api needed to prevent premature destruction
2586         // bits are not in the same order as a normal i80 APInt, compensate.
2587         APInt api = CFP->getValueAPF().bitcastToAPInt();
2588         const uint64_t *p = api.getRawData();
2589         Record.push_back((p[1] << 48) | (p[0] >> 16));
2590         Record.push_back(p[0] & 0xffffLL);
2591       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
2592         APInt api = CFP->getValueAPF().bitcastToAPInt();
2593         const uint64_t *p = api.getRawData();
2594         Record.push_back(p[0]);
2595         Record.push_back(p[1]);
2596       } else {
2597         assert(0 && "Unknown FP type!");
2598       }
2599     } else if (isa<ConstantDataSequential>(C) &&
2600                cast<ConstantDataSequential>(C)->isString()) {
2601       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
2602       // Emit constant strings specially.
2603       unsigned NumElts = Str->getNumElements();
2604       // If this is a null-terminated string, use the denser CSTRING encoding.
2605       if (Str->isCString()) {
2606         Code = bitc::CST_CODE_CSTRING;
2607         --NumElts;  // Don't encode the null, which isn't allowed by char6.
2608       } else {
2609         Code = bitc::CST_CODE_STRING;
2610         AbbrevToUse = String8Abbrev;
2611       }
2612       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
2613       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
2614       for (unsigned i = 0; i != NumElts; ++i) {
2615         unsigned char V = Str->getElementAsInteger(i);
2616         Record.push_back(V);
2617         isCStr7 &= (V & 128) == 0;
2618         if (isCStrChar6)
2619           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
2620       }
2621 
2622       if (isCStrChar6)
2623         AbbrevToUse = CString6Abbrev;
2624       else if (isCStr7)
2625         AbbrevToUse = CString7Abbrev;
2626     } else if (const ConstantDataSequential *CDS =
2627                   dyn_cast<ConstantDataSequential>(C)) {
2628       Code = bitc::CST_CODE_DATA;
2629       Type *EltTy = CDS->getElementType();
2630       if (isa<IntegerType>(EltTy)) {
2631         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2632           Record.push_back(CDS->getElementAsInteger(i));
2633       } else {
2634         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2635           Record.push_back(
2636               CDS->getElementAsAPFloat(i).bitcastToAPInt().getLimitedValue());
2637       }
2638     } else if (isa<ConstantAggregate>(C)) {
2639       Code = bitc::CST_CODE_AGGREGATE;
2640       for (const Value *Op : C->operands())
2641         Record.push_back(VE.getValueID(Op));
2642       AbbrevToUse = AggregateAbbrev;
2643     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
2644       switch (CE->getOpcode()) {
2645       default:
2646         if (Instruction::isCast(CE->getOpcode())) {
2647           Code = bitc::CST_CODE_CE_CAST;
2648           Record.push_back(getEncodedCastOpcode(CE->getOpcode()));
2649           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2650           Record.push_back(VE.getValueID(C->getOperand(0)));
2651           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
2652         } else {
2653           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
2654           Code = bitc::CST_CODE_CE_BINOP;
2655           Record.push_back(getEncodedBinaryOpcode(CE->getOpcode()));
2656           Record.push_back(VE.getValueID(C->getOperand(0)));
2657           Record.push_back(VE.getValueID(C->getOperand(1)));
2658           uint64_t Flags = getOptimizationFlags(CE);
2659           if (Flags != 0)
2660             Record.push_back(Flags);
2661         }
2662         break;
2663       case Instruction::FNeg: {
2664         assert(CE->getNumOperands() == 1 && "Unknown constant expr!");
2665         Code = bitc::CST_CODE_CE_UNOP;
2666         Record.push_back(getEncodedUnaryOpcode(CE->getOpcode()));
2667         Record.push_back(VE.getValueID(C->getOperand(0)));
2668         uint64_t Flags = getOptimizationFlags(CE);
2669         if (Flags != 0)
2670           Record.push_back(Flags);
2671         break;
2672       }
2673       case Instruction::GetElementPtr: {
2674         Code = bitc::CST_CODE_CE_GEP;
2675         const auto *GO = cast<GEPOperator>(C);
2676         Record.push_back(VE.getTypeID(GO->getSourceElementType()));
2677         if (std::optional<unsigned> Idx = GO->getInRangeIndex()) {
2678           Code = bitc::CST_CODE_CE_GEP_WITH_INRANGE_INDEX;
2679           Record.push_back((*Idx << 1) | GO->isInBounds());
2680         } else if (GO->isInBounds())
2681           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
2682         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
2683           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
2684           Record.push_back(VE.getValueID(C->getOperand(i)));
2685         }
2686         break;
2687       }
2688       case Instruction::Select:
2689         Code = bitc::CST_CODE_CE_SELECT;
2690         Record.push_back(VE.getValueID(C->getOperand(0)));
2691         Record.push_back(VE.getValueID(C->getOperand(1)));
2692         Record.push_back(VE.getValueID(C->getOperand(2)));
2693         break;
2694       case Instruction::ExtractElement:
2695         Code = bitc::CST_CODE_CE_EXTRACTELT;
2696         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2697         Record.push_back(VE.getValueID(C->getOperand(0)));
2698         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
2699         Record.push_back(VE.getValueID(C->getOperand(1)));
2700         break;
2701       case Instruction::InsertElement:
2702         Code = bitc::CST_CODE_CE_INSERTELT;
2703         Record.push_back(VE.getValueID(C->getOperand(0)));
2704         Record.push_back(VE.getValueID(C->getOperand(1)));
2705         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
2706         Record.push_back(VE.getValueID(C->getOperand(2)));
2707         break;
2708       case Instruction::ShuffleVector:
2709         // If the return type and argument types are the same, this is a
2710         // standard shufflevector instruction.  If the types are different,
2711         // then the shuffle is widening or truncating the input vectors, and
2712         // the argument type must also be encoded.
2713         if (C->getType() == C->getOperand(0)->getType()) {
2714           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
2715         } else {
2716           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
2717           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2718         }
2719         Record.push_back(VE.getValueID(C->getOperand(0)));
2720         Record.push_back(VE.getValueID(C->getOperand(1)));
2721         Record.push_back(VE.getValueID(CE->getShuffleMaskForBitcode()));
2722         break;
2723       case Instruction::ICmp:
2724       case Instruction::FCmp:
2725         Code = bitc::CST_CODE_CE_CMP;
2726         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2727         Record.push_back(VE.getValueID(C->getOperand(0)));
2728         Record.push_back(VE.getValueID(C->getOperand(1)));
2729         Record.push_back(CE->getPredicate());
2730         break;
2731       }
2732     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
2733       Code = bitc::CST_CODE_BLOCKADDRESS;
2734       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
2735       Record.push_back(VE.getValueID(BA->getFunction()));
2736       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
2737     } else if (const auto *Equiv = dyn_cast<DSOLocalEquivalent>(C)) {
2738       Code = bitc::CST_CODE_DSO_LOCAL_EQUIVALENT;
2739       Record.push_back(VE.getTypeID(Equiv->getGlobalValue()->getType()));
2740       Record.push_back(VE.getValueID(Equiv->getGlobalValue()));
2741     } else if (const auto *NC = dyn_cast<NoCFIValue>(C)) {
2742       Code = bitc::CST_CODE_NO_CFI_VALUE;
2743       Record.push_back(VE.getTypeID(NC->getGlobalValue()->getType()));
2744       Record.push_back(VE.getValueID(NC->getGlobalValue()));
2745     } else {
2746 #ifndef NDEBUG
2747       C->dump();
2748 #endif
2749       llvm_unreachable("Unknown constant!");
2750     }
2751     Stream.EmitRecord(Code, Record, AbbrevToUse);
2752     Record.clear();
2753   }
2754 
2755   Stream.ExitBlock();
2756 }
2757 
2758 void ModuleBitcodeWriter::writeModuleConstants() {
2759   const ValueEnumerator::ValueList &Vals = VE.getValues();
2760 
2761   // Find the first constant to emit, which is the first non-globalvalue value.
2762   // We know globalvalues have been emitted by WriteModuleInfo.
2763   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
2764     if (!isa<GlobalValue>(Vals[i].first)) {
2765       writeConstants(i, Vals.size(), true);
2766       return;
2767     }
2768   }
2769 }
2770 
2771 /// pushValueAndType - The file has to encode both the value and type id for
2772 /// many values, because we need to know what type to create for forward
2773 /// references.  However, most operands are not forward references, so this type
2774 /// field is not needed.
2775 ///
2776 /// This function adds V's value ID to Vals.  If the value ID is higher than the
2777 /// instruction ID, then it is a forward reference, and it also includes the
2778 /// type ID.  The value ID that is written is encoded relative to the InstID.
2779 bool ModuleBitcodeWriter::pushValueAndType(const Value *V, unsigned InstID,
2780                                            SmallVectorImpl<unsigned> &Vals) {
2781   unsigned ValID = VE.getValueID(V);
2782   // Make encoding relative to the InstID.
2783   Vals.push_back(InstID - ValID);
2784   if (ValID >= InstID) {
2785     Vals.push_back(VE.getTypeID(V->getType()));
2786     return true;
2787   }
2788   return false;
2789 }
2790 
2791 void ModuleBitcodeWriter::writeOperandBundles(const CallBase &CS,
2792                                               unsigned InstID) {
2793   SmallVector<unsigned, 64> Record;
2794   LLVMContext &C = CS.getContext();
2795 
2796   for (unsigned i = 0, e = CS.getNumOperandBundles(); i != e; ++i) {
2797     const auto &Bundle = CS.getOperandBundleAt(i);
2798     Record.push_back(C.getOperandBundleTagID(Bundle.getTagName()));
2799 
2800     for (auto &Input : Bundle.Inputs)
2801       pushValueAndType(Input, InstID, Record);
2802 
2803     Stream.EmitRecord(bitc::FUNC_CODE_OPERAND_BUNDLE, Record);
2804     Record.clear();
2805   }
2806 }
2807 
2808 /// pushValue - Like pushValueAndType, but where the type of the value is
2809 /// omitted (perhaps it was already encoded in an earlier operand).
2810 void ModuleBitcodeWriter::pushValue(const Value *V, unsigned InstID,
2811                                     SmallVectorImpl<unsigned> &Vals) {
2812   unsigned ValID = VE.getValueID(V);
2813   Vals.push_back(InstID - ValID);
2814 }
2815 
2816 void ModuleBitcodeWriter::pushValueSigned(const Value *V, unsigned InstID,
2817                                           SmallVectorImpl<uint64_t> &Vals) {
2818   unsigned ValID = VE.getValueID(V);
2819   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
2820   emitSignedInt64(Vals, diff);
2821 }
2822 
2823 /// WriteInstruction - Emit an instruction to the specified stream.
2824 void ModuleBitcodeWriter::writeInstruction(const Instruction &I,
2825                                            unsigned InstID,
2826                                            SmallVectorImpl<unsigned> &Vals) {
2827   unsigned Code = 0;
2828   unsigned AbbrevToUse = 0;
2829   VE.setInstructionID(&I);
2830   switch (I.getOpcode()) {
2831   default:
2832     if (Instruction::isCast(I.getOpcode())) {
2833       Code = bitc::FUNC_CODE_INST_CAST;
2834       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2835         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
2836       Vals.push_back(VE.getTypeID(I.getType()));
2837       Vals.push_back(getEncodedCastOpcode(I.getOpcode()));
2838     } else {
2839       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
2840       Code = bitc::FUNC_CODE_INST_BINOP;
2841       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2842         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
2843       pushValue(I.getOperand(1), InstID, Vals);
2844       Vals.push_back(getEncodedBinaryOpcode(I.getOpcode()));
2845       uint64_t Flags = getOptimizationFlags(&I);
2846       if (Flags != 0) {
2847         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
2848           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
2849         Vals.push_back(Flags);
2850       }
2851     }
2852     break;
2853   case Instruction::FNeg: {
2854     Code = bitc::FUNC_CODE_INST_UNOP;
2855     if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2856       AbbrevToUse = FUNCTION_INST_UNOP_ABBREV;
2857     Vals.push_back(getEncodedUnaryOpcode(I.getOpcode()));
2858     uint64_t Flags = getOptimizationFlags(&I);
2859     if (Flags != 0) {
2860       if (AbbrevToUse == FUNCTION_INST_UNOP_ABBREV)
2861         AbbrevToUse = FUNCTION_INST_UNOP_FLAGS_ABBREV;
2862       Vals.push_back(Flags);
2863     }
2864     break;
2865   }
2866   case Instruction::GetElementPtr: {
2867     Code = bitc::FUNC_CODE_INST_GEP;
2868     AbbrevToUse = FUNCTION_INST_GEP_ABBREV;
2869     auto &GEPInst = cast<GetElementPtrInst>(I);
2870     Vals.push_back(GEPInst.isInBounds());
2871     Vals.push_back(VE.getTypeID(GEPInst.getSourceElementType()));
2872     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
2873       pushValueAndType(I.getOperand(i), InstID, Vals);
2874     break;
2875   }
2876   case Instruction::ExtractValue: {
2877     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
2878     pushValueAndType(I.getOperand(0), InstID, Vals);
2879     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
2880     Vals.append(EVI->idx_begin(), EVI->idx_end());
2881     break;
2882   }
2883   case Instruction::InsertValue: {
2884     Code = bitc::FUNC_CODE_INST_INSERTVAL;
2885     pushValueAndType(I.getOperand(0), InstID, Vals);
2886     pushValueAndType(I.getOperand(1), InstID, Vals);
2887     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
2888     Vals.append(IVI->idx_begin(), IVI->idx_end());
2889     break;
2890   }
2891   case Instruction::Select: {
2892     Code = bitc::FUNC_CODE_INST_VSELECT;
2893     pushValueAndType(I.getOperand(1), InstID, Vals);
2894     pushValue(I.getOperand(2), InstID, Vals);
2895     pushValueAndType(I.getOperand(0), InstID, Vals);
2896     uint64_t Flags = getOptimizationFlags(&I);
2897     if (Flags != 0)
2898       Vals.push_back(Flags);
2899     break;
2900   }
2901   case Instruction::ExtractElement:
2902     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
2903     pushValueAndType(I.getOperand(0), InstID, Vals);
2904     pushValueAndType(I.getOperand(1), InstID, Vals);
2905     break;
2906   case Instruction::InsertElement:
2907     Code = bitc::FUNC_CODE_INST_INSERTELT;
2908     pushValueAndType(I.getOperand(0), InstID, Vals);
2909     pushValue(I.getOperand(1), InstID, Vals);
2910     pushValueAndType(I.getOperand(2), InstID, Vals);
2911     break;
2912   case Instruction::ShuffleVector:
2913     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
2914     pushValueAndType(I.getOperand(0), InstID, Vals);
2915     pushValue(I.getOperand(1), InstID, Vals);
2916     pushValue(cast<ShuffleVectorInst>(I).getShuffleMaskForBitcode(), InstID,
2917               Vals);
2918     break;
2919   case Instruction::ICmp:
2920   case Instruction::FCmp: {
2921     // compare returning Int1Ty or vector of Int1Ty
2922     Code = bitc::FUNC_CODE_INST_CMP2;
2923     pushValueAndType(I.getOperand(0), InstID, Vals);
2924     pushValue(I.getOperand(1), InstID, Vals);
2925     Vals.push_back(cast<CmpInst>(I).getPredicate());
2926     uint64_t Flags = getOptimizationFlags(&I);
2927     if (Flags != 0)
2928       Vals.push_back(Flags);
2929     break;
2930   }
2931 
2932   case Instruction::Ret:
2933     {
2934       Code = bitc::FUNC_CODE_INST_RET;
2935       unsigned NumOperands = I.getNumOperands();
2936       if (NumOperands == 0)
2937         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
2938       else if (NumOperands == 1) {
2939         if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2940           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
2941       } else {
2942         for (unsigned i = 0, e = NumOperands; i != e; ++i)
2943           pushValueAndType(I.getOperand(i), InstID, Vals);
2944       }
2945     }
2946     break;
2947   case Instruction::Br:
2948     {
2949       Code = bitc::FUNC_CODE_INST_BR;
2950       const BranchInst &II = cast<BranchInst>(I);
2951       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
2952       if (II.isConditional()) {
2953         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
2954         pushValue(II.getCondition(), InstID, Vals);
2955       }
2956     }
2957     break;
2958   case Instruction::Switch:
2959     {
2960       Code = bitc::FUNC_CODE_INST_SWITCH;
2961       const SwitchInst &SI = cast<SwitchInst>(I);
2962       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
2963       pushValue(SI.getCondition(), InstID, Vals);
2964       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
2965       for (auto Case : SI.cases()) {
2966         Vals.push_back(VE.getValueID(Case.getCaseValue()));
2967         Vals.push_back(VE.getValueID(Case.getCaseSuccessor()));
2968       }
2969     }
2970     break;
2971   case Instruction::IndirectBr:
2972     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
2973     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2974     // Encode the address operand as relative, but not the basic blocks.
2975     pushValue(I.getOperand(0), InstID, Vals);
2976     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
2977       Vals.push_back(VE.getValueID(I.getOperand(i)));
2978     break;
2979 
2980   case Instruction::Invoke: {
2981     const InvokeInst *II = cast<InvokeInst>(&I);
2982     const Value *Callee = II->getCalledOperand();
2983     FunctionType *FTy = II->getFunctionType();
2984 
2985     if (II->hasOperandBundles())
2986       writeOperandBundles(*II, InstID);
2987 
2988     Code = bitc::FUNC_CODE_INST_INVOKE;
2989 
2990     Vals.push_back(VE.getAttributeListID(II->getAttributes()));
2991     Vals.push_back(II->getCallingConv() | 1 << 13);
2992     Vals.push_back(VE.getValueID(II->getNormalDest()));
2993     Vals.push_back(VE.getValueID(II->getUnwindDest()));
2994     Vals.push_back(VE.getTypeID(FTy));
2995     pushValueAndType(Callee, InstID, Vals);
2996 
2997     // Emit value #'s for the fixed parameters.
2998     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
2999       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
3000 
3001     // Emit type/value pairs for varargs params.
3002     if (FTy->isVarArg()) {
3003       for (unsigned i = FTy->getNumParams(), e = II->arg_size(); i != e; ++i)
3004         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
3005     }
3006     break;
3007   }
3008   case Instruction::Resume:
3009     Code = bitc::FUNC_CODE_INST_RESUME;
3010     pushValueAndType(I.getOperand(0), InstID, Vals);
3011     break;
3012   case Instruction::CleanupRet: {
3013     Code = bitc::FUNC_CODE_INST_CLEANUPRET;
3014     const auto &CRI = cast<CleanupReturnInst>(I);
3015     pushValue(CRI.getCleanupPad(), InstID, Vals);
3016     if (CRI.hasUnwindDest())
3017       Vals.push_back(VE.getValueID(CRI.getUnwindDest()));
3018     break;
3019   }
3020   case Instruction::CatchRet: {
3021     Code = bitc::FUNC_CODE_INST_CATCHRET;
3022     const auto &CRI = cast<CatchReturnInst>(I);
3023     pushValue(CRI.getCatchPad(), InstID, Vals);
3024     Vals.push_back(VE.getValueID(CRI.getSuccessor()));
3025     break;
3026   }
3027   case Instruction::CleanupPad:
3028   case Instruction::CatchPad: {
3029     const auto &FuncletPad = cast<FuncletPadInst>(I);
3030     Code = isa<CatchPadInst>(FuncletPad) ? bitc::FUNC_CODE_INST_CATCHPAD
3031                                          : bitc::FUNC_CODE_INST_CLEANUPPAD;
3032     pushValue(FuncletPad.getParentPad(), InstID, Vals);
3033 
3034     unsigned NumArgOperands = FuncletPad.arg_size();
3035     Vals.push_back(NumArgOperands);
3036     for (unsigned Op = 0; Op != NumArgOperands; ++Op)
3037       pushValueAndType(FuncletPad.getArgOperand(Op), InstID, Vals);
3038     break;
3039   }
3040   case Instruction::CatchSwitch: {
3041     Code = bitc::FUNC_CODE_INST_CATCHSWITCH;
3042     const auto &CatchSwitch = cast<CatchSwitchInst>(I);
3043 
3044     pushValue(CatchSwitch.getParentPad(), InstID, Vals);
3045 
3046     unsigned NumHandlers = CatchSwitch.getNumHandlers();
3047     Vals.push_back(NumHandlers);
3048     for (const BasicBlock *CatchPadBB : CatchSwitch.handlers())
3049       Vals.push_back(VE.getValueID(CatchPadBB));
3050 
3051     if (CatchSwitch.hasUnwindDest())
3052       Vals.push_back(VE.getValueID(CatchSwitch.getUnwindDest()));
3053     break;
3054   }
3055   case Instruction::CallBr: {
3056     const CallBrInst *CBI = cast<CallBrInst>(&I);
3057     const Value *Callee = CBI->getCalledOperand();
3058     FunctionType *FTy = CBI->getFunctionType();
3059 
3060     if (CBI->hasOperandBundles())
3061       writeOperandBundles(*CBI, InstID);
3062 
3063     Code = bitc::FUNC_CODE_INST_CALLBR;
3064 
3065     Vals.push_back(VE.getAttributeListID(CBI->getAttributes()));
3066 
3067     Vals.push_back(CBI->getCallingConv() << bitc::CALL_CCONV |
3068                    1 << bitc::CALL_EXPLICIT_TYPE);
3069 
3070     Vals.push_back(VE.getValueID(CBI->getDefaultDest()));
3071     Vals.push_back(CBI->getNumIndirectDests());
3072     for (unsigned i = 0, e = CBI->getNumIndirectDests(); i != e; ++i)
3073       Vals.push_back(VE.getValueID(CBI->getIndirectDest(i)));
3074 
3075     Vals.push_back(VE.getTypeID(FTy));
3076     pushValueAndType(Callee, InstID, Vals);
3077 
3078     // Emit value #'s for the fixed parameters.
3079     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
3080       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
3081 
3082     // Emit type/value pairs for varargs params.
3083     if (FTy->isVarArg()) {
3084       for (unsigned i = FTy->getNumParams(), e = CBI->arg_size(); i != e; ++i)
3085         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
3086     }
3087     break;
3088   }
3089   case Instruction::Unreachable:
3090     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
3091     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
3092     break;
3093 
3094   case Instruction::PHI: {
3095     const PHINode &PN = cast<PHINode>(I);
3096     Code = bitc::FUNC_CODE_INST_PHI;
3097     // With the newer instruction encoding, forward references could give
3098     // negative valued IDs.  This is most common for PHIs, so we use
3099     // signed VBRs.
3100     SmallVector<uint64_t, 128> Vals64;
3101     Vals64.push_back(VE.getTypeID(PN.getType()));
3102     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
3103       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64);
3104       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
3105     }
3106 
3107     uint64_t Flags = getOptimizationFlags(&I);
3108     if (Flags != 0)
3109       Vals64.push_back(Flags);
3110 
3111     // Emit a Vals64 vector and exit.
3112     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
3113     Vals64.clear();
3114     return;
3115   }
3116 
3117   case Instruction::LandingPad: {
3118     const LandingPadInst &LP = cast<LandingPadInst>(I);
3119     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
3120     Vals.push_back(VE.getTypeID(LP.getType()));
3121     Vals.push_back(LP.isCleanup());
3122     Vals.push_back(LP.getNumClauses());
3123     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
3124       if (LP.isCatch(I))
3125         Vals.push_back(LandingPadInst::Catch);
3126       else
3127         Vals.push_back(LandingPadInst::Filter);
3128       pushValueAndType(LP.getClause(I), InstID, Vals);
3129     }
3130     break;
3131   }
3132 
3133   case Instruction::Alloca: {
3134     Code = bitc::FUNC_CODE_INST_ALLOCA;
3135     const AllocaInst &AI = cast<AllocaInst>(I);
3136     Vals.push_back(VE.getTypeID(AI.getAllocatedType()));
3137     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
3138     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
3139     using APV = AllocaPackedValues;
3140     unsigned Record = 0;
3141     unsigned EncodedAlign = getEncodedAlign(AI.getAlign());
3142     Bitfield::set<APV::AlignLower>(
3143         Record, EncodedAlign & ((1 << APV::AlignLower::Bits) - 1));
3144     Bitfield::set<APV::AlignUpper>(Record,
3145                                    EncodedAlign >> APV::AlignLower::Bits);
3146     Bitfield::set<APV::UsedWithInAlloca>(Record, AI.isUsedWithInAlloca());
3147     Bitfield::set<APV::ExplicitType>(Record, true);
3148     Bitfield::set<APV::SwiftError>(Record, AI.isSwiftError());
3149     Vals.push_back(Record);
3150 
3151     unsigned AS = AI.getAddressSpace();
3152     if (AS != M.getDataLayout().getAllocaAddrSpace())
3153       Vals.push_back(AS);
3154     break;
3155   }
3156 
3157   case Instruction::Load:
3158     if (cast<LoadInst>(I).isAtomic()) {
3159       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
3160       pushValueAndType(I.getOperand(0), InstID, Vals);
3161     } else {
3162       Code = bitc::FUNC_CODE_INST_LOAD;
3163       if (!pushValueAndType(I.getOperand(0), InstID, Vals)) // ptr
3164         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
3165     }
3166     Vals.push_back(VE.getTypeID(I.getType()));
3167     Vals.push_back(getEncodedAlign(cast<LoadInst>(I).getAlign()));
3168     Vals.push_back(cast<LoadInst>(I).isVolatile());
3169     if (cast<LoadInst>(I).isAtomic()) {
3170       Vals.push_back(getEncodedOrdering(cast<LoadInst>(I).getOrdering()));
3171       Vals.push_back(getEncodedSyncScopeID(cast<LoadInst>(I).getSyncScopeID()));
3172     }
3173     break;
3174   case Instruction::Store:
3175     if (cast<StoreInst>(I).isAtomic())
3176       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
3177     else
3178       Code = bitc::FUNC_CODE_INST_STORE;
3179     pushValueAndType(I.getOperand(1), InstID, Vals); // ptrty + ptr
3180     pushValueAndType(I.getOperand(0), InstID, Vals); // valty + val
3181     Vals.push_back(getEncodedAlign(cast<StoreInst>(I).getAlign()));
3182     Vals.push_back(cast<StoreInst>(I).isVolatile());
3183     if (cast<StoreInst>(I).isAtomic()) {
3184       Vals.push_back(getEncodedOrdering(cast<StoreInst>(I).getOrdering()));
3185       Vals.push_back(
3186           getEncodedSyncScopeID(cast<StoreInst>(I).getSyncScopeID()));
3187     }
3188     break;
3189   case Instruction::AtomicCmpXchg:
3190     Code = bitc::FUNC_CODE_INST_CMPXCHG;
3191     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
3192     pushValueAndType(I.getOperand(1), InstID, Vals); // cmp.
3193     pushValue(I.getOperand(2), InstID, Vals);        // newval.
3194     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
3195     Vals.push_back(
3196         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
3197     Vals.push_back(
3198         getEncodedSyncScopeID(cast<AtomicCmpXchgInst>(I).getSyncScopeID()));
3199     Vals.push_back(
3200         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
3201     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
3202     Vals.push_back(getEncodedAlign(cast<AtomicCmpXchgInst>(I).getAlign()));
3203     break;
3204   case Instruction::AtomicRMW:
3205     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
3206     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
3207     pushValueAndType(I.getOperand(1), InstID, Vals); // valty + val
3208     Vals.push_back(
3209         getEncodedRMWOperation(cast<AtomicRMWInst>(I).getOperation()));
3210     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
3211     Vals.push_back(getEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
3212     Vals.push_back(
3213         getEncodedSyncScopeID(cast<AtomicRMWInst>(I).getSyncScopeID()));
3214     Vals.push_back(getEncodedAlign(cast<AtomicRMWInst>(I).getAlign()));
3215     break;
3216   case Instruction::Fence:
3217     Code = bitc::FUNC_CODE_INST_FENCE;
3218     Vals.push_back(getEncodedOrdering(cast<FenceInst>(I).getOrdering()));
3219     Vals.push_back(getEncodedSyncScopeID(cast<FenceInst>(I).getSyncScopeID()));
3220     break;
3221   case Instruction::Call: {
3222     const CallInst &CI = cast<CallInst>(I);
3223     FunctionType *FTy = CI.getFunctionType();
3224 
3225     if (CI.hasOperandBundles())
3226       writeOperandBundles(CI, InstID);
3227 
3228     Code = bitc::FUNC_CODE_INST_CALL;
3229 
3230     Vals.push_back(VE.getAttributeListID(CI.getAttributes()));
3231 
3232     unsigned Flags = getOptimizationFlags(&I);
3233     Vals.push_back(CI.getCallingConv() << bitc::CALL_CCONV |
3234                    unsigned(CI.isTailCall()) << bitc::CALL_TAIL |
3235                    unsigned(CI.isMustTailCall()) << bitc::CALL_MUSTTAIL |
3236                    1 << bitc::CALL_EXPLICIT_TYPE |
3237                    unsigned(CI.isNoTailCall()) << bitc::CALL_NOTAIL |
3238                    unsigned(Flags != 0) << bitc::CALL_FMF);
3239     if (Flags != 0)
3240       Vals.push_back(Flags);
3241 
3242     Vals.push_back(VE.getTypeID(FTy));
3243     pushValueAndType(CI.getCalledOperand(), InstID, Vals); // Callee
3244 
3245     // Emit value #'s for the fixed parameters.
3246     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
3247       // Check for labels (can happen with asm labels).
3248       if (FTy->getParamType(i)->isLabelTy())
3249         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
3250       else
3251         pushValue(CI.getArgOperand(i), InstID, Vals); // fixed param.
3252     }
3253 
3254     // Emit type/value pairs for varargs params.
3255     if (FTy->isVarArg()) {
3256       for (unsigned i = FTy->getNumParams(), e = CI.arg_size(); i != e; ++i)
3257         pushValueAndType(CI.getArgOperand(i), InstID, Vals); // varargs
3258     }
3259     break;
3260   }
3261   case Instruction::VAArg:
3262     Code = bitc::FUNC_CODE_INST_VAARG;
3263     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
3264     pushValue(I.getOperand(0), InstID, Vals);                   // valist.
3265     Vals.push_back(VE.getTypeID(I.getType())); // restype.
3266     break;
3267   case Instruction::Freeze:
3268     Code = bitc::FUNC_CODE_INST_FREEZE;
3269     pushValueAndType(I.getOperand(0), InstID, Vals);
3270     break;
3271   }
3272 
3273   Stream.EmitRecord(Code, Vals, AbbrevToUse);
3274   Vals.clear();
3275 }
3276 
3277 /// Write a GlobalValue VST to the module. The purpose of this data structure is
3278 /// to allow clients to efficiently find the function body.
3279 void ModuleBitcodeWriter::writeGlobalValueSymbolTable(
3280   DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3281   // Get the offset of the VST we are writing, and backpatch it into
3282   // the VST forward declaration record.
3283   uint64_t VSTOffset = Stream.GetCurrentBitNo();
3284   // The BitcodeStartBit was the stream offset of the identification block.
3285   VSTOffset -= bitcodeStartBit();
3286   assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
3287   // Note that we add 1 here because the offset is relative to one word
3288   // before the start of the identification block, which was historically
3289   // always the start of the regular bitcode header.
3290   Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32 + 1);
3291 
3292   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3293 
3294   auto Abbv = std::make_shared<BitCodeAbbrev>();
3295   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
3296   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
3297   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
3298   unsigned FnEntryAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3299 
3300   for (const Function &F : M) {
3301     uint64_t Record[2];
3302 
3303     if (F.isDeclaration())
3304       continue;
3305 
3306     Record[0] = VE.getValueID(&F);
3307 
3308     // Save the word offset of the function (from the start of the
3309     // actual bitcode written to the stream).
3310     uint64_t BitcodeIndex = FunctionToBitcodeIndex[&F] - bitcodeStartBit();
3311     assert((BitcodeIndex & 31) == 0 && "function block not 32-bit aligned");
3312     // Note that we add 1 here because the offset is relative to one word
3313     // before the start of the identification block, which was historically
3314     // always the start of the regular bitcode header.
3315     Record[1] = BitcodeIndex / 32 + 1;
3316 
3317     Stream.EmitRecord(bitc::VST_CODE_FNENTRY, Record, FnEntryAbbrev);
3318   }
3319 
3320   Stream.ExitBlock();
3321 }
3322 
3323 /// Emit names for arguments, instructions and basic blocks in a function.
3324 void ModuleBitcodeWriter::writeFunctionLevelValueSymbolTable(
3325     const ValueSymbolTable &VST) {
3326   if (VST.empty())
3327     return;
3328 
3329   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3330 
3331   // FIXME: Set up the abbrev, we know how many values there are!
3332   // FIXME: We know if the type names can use 7-bit ascii.
3333   SmallVector<uint64_t, 64> NameVals;
3334 
3335   for (const ValueName &Name : VST) {
3336     // Figure out the encoding to use for the name.
3337     StringEncoding Bits = getStringEncoding(Name.getKey());
3338 
3339     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
3340     NameVals.push_back(VE.getValueID(Name.getValue()));
3341 
3342     // VST_CODE_ENTRY:   [valueid, namechar x N]
3343     // VST_CODE_BBENTRY: [bbid, namechar x N]
3344     unsigned Code;
3345     if (isa<BasicBlock>(Name.getValue())) {
3346       Code = bitc::VST_CODE_BBENTRY;
3347       if (Bits == SE_Char6)
3348         AbbrevToUse = VST_BBENTRY_6_ABBREV;
3349     } else {
3350       Code = bitc::VST_CODE_ENTRY;
3351       if (Bits == SE_Char6)
3352         AbbrevToUse = VST_ENTRY_6_ABBREV;
3353       else if (Bits == SE_Fixed7)
3354         AbbrevToUse = VST_ENTRY_7_ABBREV;
3355     }
3356 
3357     for (const auto P : Name.getKey())
3358       NameVals.push_back((unsigned char)P);
3359 
3360     // Emit the finished record.
3361     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
3362     NameVals.clear();
3363   }
3364 
3365   Stream.ExitBlock();
3366 }
3367 
3368 void ModuleBitcodeWriter::writeUseList(UseListOrder &&Order) {
3369   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
3370   unsigned Code;
3371   if (isa<BasicBlock>(Order.V))
3372     Code = bitc::USELIST_CODE_BB;
3373   else
3374     Code = bitc::USELIST_CODE_DEFAULT;
3375 
3376   SmallVector<uint64_t, 64> Record(Order.Shuffle.begin(), Order.Shuffle.end());
3377   Record.push_back(VE.getValueID(Order.V));
3378   Stream.EmitRecord(Code, Record);
3379 }
3380 
3381 void ModuleBitcodeWriter::writeUseListBlock(const Function *F) {
3382   assert(VE.shouldPreserveUseListOrder() &&
3383          "Expected to be preserving use-list order");
3384 
3385   auto hasMore = [&]() {
3386     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
3387   };
3388   if (!hasMore())
3389     // Nothing to do.
3390     return;
3391 
3392   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
3393   while (hasMore()) {
3394     writeUseList(std::move(VE.UseListOrders.back()));
3395     VE.UseListOrders.pop_back();
3396   }
3397   Stream.ExitBlock();
3398 }
3399 
3400 /// Emit a function body to the module stream.
3401 void ModuleBitcodeWriter::writeFunction(
3402     const Function &F,
3403     DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3404   // Save the bitcode index of the start of this function block for recording
3405   // in the VST.
3406   FunctionToBitcodeIndex[&F] = Stream.GetCurrentBitNo();
3407 
3408   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
3409   VE.incorporateFunction(F);
3410 
3411   SmallVector<unsigned, 64> Vals;
3412 
3413   // Emit the number of basic blocks, so the reader can create them ahead of
3414   // time.
3415   Vals.push_back(VE.getBasicBlocks().size());
3416   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
3417   Vals.clear();
3418 
3419   // If there are function-local constants, emit them now.
3420   unsigned CstStart, CstEnd;
3421   VE.getFunctionConstantRange(CstStart, CstEnd);
3422   writeConstants(CstStart, CstEnd, false);
3423 
3424   // If there is function-local metadata, emit it now.
3425   writeFunctionMetadata(F);
3426 
3427   // Keep a running idea of what the instruction ID is.
3428   unsigned InstID = CstEnd;
3429 
3430   bool NeedsMetadataAttachment = F.hasMetadata();
3431 
3432   DILocation *LastDL = nullptr;
3433   SmallSetVector<Function *, 4> BlockAddressUsers;
3434 
3435   // Finally, emit all the instructions, in order.
3436   for (const BasicBlock &BB : F) {
3437     for (const Instruction &I : BB) {
3438       writeInstruction(I, InstID, Vals);
3439 
3440       if (!I.getType()->isVoidTy())
3441         ++InstID;
3442 
3443       // If the instruction has metadata, write a metadata attachment later.
3444       NeedsMetadataAttachment |= I.hasMetadataOtherThanDebugLoc();
3445 
3446       // If the instruction has a debug location, emit it.
3447       DILocation *DL = I.getDebugLoc();
3448       if (!DL)
3449         continue;
3450 
3451       if (DL == LastDL) {
3452         // Just repeat the same debug loc as last time.
3453         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
3454         continue;
3455       }
3456 
3457       Vals.push_back(DL->getLine());
3458       Vals.push_back(DL->getColumn());
3459       Vals.push_back(VE.getMetadataOrNullID(DL->getScope()));
3460       Vals.push_back(VE.getMetadataOrNullID(DL->getInlinedAt()));
3461       Vals.push_back(DL->isImplicitCode());
3462       Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
3463       Vals.clear();
3464 
3465       LastDL = DL;
3466     }
3467 
3468     if (BlockAddress *BA = BlockAddress::lookup(&BB)) {
3469       SmallVector<Value *> Worklist{BA};
3470       SmallPtrSet<Value *, 8> Visited{BA};
3471       while (!Worklist.empty()) {
3472         Value *V = Worklist.pop_back_val();
3473         for (User *U : V->users()) {
3474           if (auto *I = dyn_cast<Instruction>(U)) {
3475             Function *P = I->getFunction();
3476             if (P != &F)
3477               BlockAddressUsers.insert(P);
3478           } else if (isa<Constant>(U) && !isa<GlobalValue>(U) &&
3479                      Visited.insert(U).second)
3480             Worklist.push_back(U);
3481         }
3482       }
3483     }
3484   }
3485 
3486   if (!BlockAddressUsers.empty()) {
3487     Vals.resize(BlockAddressUsers.size());
3488     for (auto I : llvm::enumerate(BlockAddressUsers))
3489       Vals[I.index()] = VE.getValueID(I.value());
3490     Stream.EmitRecord(bitc::FUNC_CODE_BLOCKADDR_USERS, Vals);
3491     Vals.clear();
3492   }
3493 
3494   // Emit names for all the instructions etc.
3495   if (auto *Symtab = F.getValueSymbolTable())
3496     writeFunctionLevelValueSymbolTable(*Symtab);
3497 
3498   if (NeedsMetadataAttachment)
3499     writeFunctionMetadataAttachment(F);
3500   if (VE.shouldPreserveUseListOrder())
3501     writeUseListBlock(&F);
3502   VE.purgeFunction();
3503   Stream.ExitBlock();
3504 }
3505 
3506 // Emit blockinfo, which defines the standard abbreviations etc.
3507 void ModuleBitcodeWriter::writeBlockInfo() {
3508   // We only want to emit block info records for blocks that have multiple
3509   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
3510   // Other blocks can define their abbrevs inline.
3511   Stream.EnterBlockInfoBlock();
3512 
3513   { // 8-bit fixed-width VST_CODE_ENTRY/VST_CODE_BBENTRY strings.
3514     auto Abbv = std::make_shared<BitCodeAbbrev>();
3515     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
3516     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3517     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3518     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3519     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3520         VST_ENTRY_8_ABBREV)
3521       llvm_unreachable("Unexpected abbrev ordering!");
3522   }
3523 
3524   { // 7-bit fixed width VST_CODE_ENTRY strings.
3525     auto Abbv = std::make_shared<BitCodeAbbrev>();
3526     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3527     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3528     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3529     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3530     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3531         VST_ENTRY_7_ABBREV)
3532       llvm_unreachable("Unexpected abbrev ordering!");
3533   }
3534   { // 6-bit char6 VST_CODE_ENTRY strings.
3535     auto Abbv = std::make_shared<BitCodeAbbrev>();
3536     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3537     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3538     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3539     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3540     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3541         VST_ENTRY_6_ABBREV)
3542       llvm_unreachable("Unexpected abbrev ordering!");
3543   }
3544   { // 6-bit char6 VST_CODE_BBENTRY strings.
3545     auto Abbv = std::make_shared<BitCodeAbbrev>();
3546     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
3547     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3548     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3549     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3550     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3551         VST_BBENTRY_6_ABBREV)
3552       llvm_unreachable("Unexpected abbrev ordering!");
3553   }
3554 
3555   { // SETTYPE abbrev for CONSTANTS_BLOCK.
3556     auto Abbv = std::make_shared<BitCodeAbbrev>();
3557     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
3558     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
3559                               VE.computeBitsRequiredForTypeIndicies()));
3560     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3561         CONSTANTS_SETTYPE_ABBREV)
3562       llvm_unreachable("Unexpected abbrev ordering!");
3563   }
3564 
3565   { // INTEGER abbrev for CONSTANTS_BLOCK.
3566     auto Abbv = std::make_shared<BitCodeAbbrev>();
3567     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
3568     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3569     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3570         CONSTANTS_INTEGER_ABBREV)
3571       llvm_unreachable("Unexpected abbrev ordering!");
3572   }
3573 
3574   { // CE_CAST abbrev for CONSTANTS_BLOCK.
3575     auto Abbv = std::make_shared<BitCodeAbbrev>();
3576     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
3577     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
3578     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
3579                               VE.computeBitsRequiredForTypeIndicies()));
3580     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
3581 
3582     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3583         CONSTANTS_CE_CAST_Abbrev)
3584       llvm_unreachable("Unexpected abbrev ordering!");
3585   }
3586   { // NULL abbrev for CONSTANTS_BLOCK.
3587     auto Abbv = std::make_shared<BitCodeAbbrev>();
3588     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
3589     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3590         CONSTANTS_NULL_Abbrev)
3591       llvm_unreachable("Unexpected abbrev ordering!");
3592   }
3593 
3594   // FIXME: This should only use space for first class types!
3595 
3596   { // INST_LOAD abbrev for FUNCTION_BLOCK.
3597     auto Abbv = std::make_shared<BitCodeAbbrev>();
3598     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
3599     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
3600     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
3601                               VE.computeBitsRequiredForTypeIndicies()));
3602     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
3603     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
3604     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3605         FUNCTION_INST_LOAD_ABBREV)
3606       llvm_unreachable("Unexpected abbrev ordering!");
3607   }
3608   { // INST_UNOP abbrev for FUNCTION_BLOCK.
3609     auto Abbv = std::make_shared<BitCodeAbbrev>();
3610     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3611     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3612     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3613     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3614         FUNCTION_INST_UNOP_ABBREV)
3615       llvm_unreachable("Unexpected abbrev ordering!");
3616   }
3617   { // INST_UNOP_FLAGS abbrev for FUNCTION_BLOCK.
3618     auto Abbv = std::make_shared<BitCodeAbbrev>();
3619     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3620     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3621     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3622     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3623     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3624         FUNCTION_INST_UNOP_FLAGS_ABBREV)
3625       llvm_unreachable("Unexpected abbrev ordering!");
3626   }
3627   { // INST_BINOP abbrev for FUNCTION_BLOCK.
3628     auto Abbv = std::make_shared<BitCodeAbbrev>();
3629     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3630     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3631     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3632     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3633     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3634         FUNCTION_INST_BINOP_ABBREV)
3635       llvm_unreachable("Unexpected abbrev ordering!");
3636   }
3637   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
3638     auto Abbv = std::make_shared<BitCodeAbbrev>();
3639     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3640     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3641     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3642     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3643     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3644     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3645         FUNCTION_INST_BINOP_FLAGS_ABBREV)
3646       llvm_unreachable("Unexpected abbrev ordering!");
3647   }
3648   { // INST_CAST abbrev for FUNCTION_BLOCK.
3649     auto Abbv = std::make_shared<BitCodeAbbrev>();
3650     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
3651     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
3652     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
3653                               VE.computeBitsRequiredForTypeIndicies()));
3654     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
3655     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3656         FUNCTION_INST_CAST_ABBREV)
3657       llvm_unreachable("Unexpected abbrev ordering!");
3658   }
3659 
3660   { // INST_RET abbrev for FUNCTION_BLOCK.
3661     auto Abbv = std::make_shared<BitCodeAbbrev>();
3662     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3663     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3664         FUNCTION_INST_RET_VOID_ABBREV)
3665       llvm_unreachable("Unexpected abbrev ordering!");
3666   }
3667   { // INST_RET abbrev for FUNCTION_BLOCK.
3668     auto Abbv = std::make_shared<BitCodeAbbrev>();
3669     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3670     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
3671     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3672         FUNCTION_INST_RET_VAL_ABBREV)
3673       llvm_unreachable("Unexpected abbrev ordering!");
3674   }
3675   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
3676     auto Abbv = std::make_shared<BitCodeAbbrev>();
3677     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
3678     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3679         FUNCTION_INST_UNREACHABLE_ABBREV)
3680       llvm_unreachable("Unexpected abbrev ordering!");
3681   }
3682   {
3683     auto Abbv = std::make_shared<BitCodeAbbrev>();
3684     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_GEP));
3685     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
3686     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, // dest ty
3687                               Log2_32_Ceil(VE.getTypes().size() + 1)));
3688     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3689     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
3690     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3691         FUNCTION_INST_GEP_ABBREV)
3692       llvm_unreachable("Unexpected abbrev ordering!");
3693   }
3694 
3695   Stream.ExitBlock();
3696 }
3697 
3698 /// Write the module path strings, currently only used when generating
3699 /// a combined index file.
3700 void IndexBitcodeWriter::writeModStrings() {
3701   Stream.EnterSubblock(bitc::MODULE_STRTAB_BLOCK_ID, 3);
3702 
3703   // TODO: See which abbrev sizes we actually need to emit
3704 
3705   // 8-bit fixed-width MST_ENTRY strings.
3706   auto Abbv = std::make_shared<BitCodeAbbrev>();
3707   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3708   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3709   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3710   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3711   unsigned Abbrev8Bit = Stream.EmitAbbrev(std::move(Abbv));
3712 
3713   // 7-bit fixed width MST_ENTRY strings.
3714   Abbv = std::make_shared<BitCodeAbbrev>();
3715   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3716   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3717   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3718   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3719   unsigned Abbrev7Bit = Stream.EmitAbbrev(std::move(Abbv));
3720 
3721   // 6-bit char6 MST_ENTRY strings.
3722   Abbv = std::make_shared<BitCodeAbbrev>();
3723   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3724   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3725   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3726   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3727   unsigned Abbrev6Bit = Stream.EmitAbbrev(std::move(Abbv));
3728 
3729   // Module Hash, 160 bits SHA1. Optionally, emitted after each MST_CODE_ENTRY.
3730   Abbv = std::make_shared<BitCodeAbbrev>();
3731   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_HASH));
3732   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3733   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3734   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3735   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3736   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3737   unsigned AbbrevHash = Stream.EmitAbbrev(std::move(Abbv));
3738 
3739   SmallVector<unsigned, 64> Vals;
3740   forEachModule(
3741       [&](const StringMapEntry<std::pair<uint64_t, ModuleHash>> &MPSE) {
3742         StringRef Key = MPSE.getKey();
3743         const auto &Value = MPSE.getValue();
3744         StringEncoding Bits = getStringEncoding(Key);
3745         unsigned AbbrevToUse = Abbrev8Bit;
3746         if (Bits == SE_Char6)
3747           AbbrevToUse = Abbrev6Bit;
3748         else if (Bits == SE_Fixed7)
3749           AbbrevToUse = Abbrev7Bit;
3750 
3751         Vals.push_back(Value.first);
3752         Vals.append(Key.begin(), Key.end());
3753 
3754         // Emit the finished record.
3755         Stream.EmitRecord(bitc::MST_CODE_ENTRY, Vals, AbbrevToUse);
3756 
3757         // Emit an optional hash for the module now
3758         const auto &Hash = Value.second;
3759         if (llvm::any_of(Hash, [](uint32_t H) { return H; })) {
3760           Vals.assign(Hash.begin(), Hash.end());
3761           // Emit the hash record.
3762           Stream.EmitRecord(bitc::MST_CODE_HASH, Vals, AbbrevHash);
3763         }
3764 
3765         Vals.clear();
3766       });
3767   Stream.ExitBlock();
3768 }
3769 
3770 /// Write the function type metadata related records that need to appear before
3771 /// a function summary entry (whether per-module or combined).
3772 template <typename Fn>
3773 static void writeFunctionTypeMetadataRecords(BitstreamWriter &Stream,
3774                                              FunctionSummary *FS,
3775                                              Fn GetValueID) {
3776   if (!FS->type_tests().empty())
3777     Stream.EmitRecord(bitc::FS_TYPE_TESTS, FS->type_tests());
3778 
3779   SmallVector<uint64_t, 64> Record;
3780 
3781   auto WriteVFuncIdVec = [&](uint64_t Ty,
3782                              ArrayRef<FunctionSummary::VFuncId> VFs) {
3783     if (VFs.empty())
3784       return;
3785     Record.clear();
3786     for (auto &VF : VFs) {
3787       Record.push_back(VF.GUID);
3788       Record.push_back(VF.Offset);
3789     }
3790     Stream.EmitRecord(Ty, Record);
3791   };
3792 
3793   WriteVFuncIdVec(bitc::FS_TYPE_TEST_ASSUME_VCALLS,
3794                   FS->type_test_assume_vcalls());
3795   WriteVFuncIdVec(bitc::FS_TYPE_CHECKED_LOAD_VCALLS,
3796                   FS->type_checked_load_vcalls());
3797 
3798   auto WriteConstVCallVec = [&](uint64_t Ty,
3799                                 ArrayRef<FunctionSummary::ConstVCall> VCs) {
3800     for (auto &VC : VCs) {
3801       Record.clear();
3802       Record.push_back(VC.VFunc.GUID);
3803       Record.push_back(VC.VFunc.Offset);
3804       llvm::append_range(Record, VC.Args);
3805       Stream.EmitRecord(Ty, Record);
3806     }
3807   };
3808 
3809   WriteConstVCallVec(bitc::FS_TYPE_TEST_ASSUME_CONST_VCALL,
3810                      FS->type_test_assume_const_vcalls());
3811   WriteConstVCallVec(bitc::FS_TYPE_CHECKED_LOAD_CONST_VCALL,
3812                      FS->type_checked_load_const_vcalls());
3813 
3814   auto WriteRange = [&](ConstantRange Range) {
3815     Range = Range.sextOrTrunc(FunctionSummary::ParamAccess::RangeWidth);
3816     assert(Range.getLower().getNumWords() == 1);
3817     assert(Range.getUpper().getNumWords() == 1);
3818     emitSignedInt64(Record, *Range.getLower().getRawData());
3819     emitSignedInt64(Record, *Range.getUpper().getRawData());
3820   };
3821 
3822   if (!FS->paramAccesses().empty()) {
3823     Record.clear();
3824     for (auto &Arg : FS->paramAccesses()) {
3825       size_t UndoSize = Record.size();
3826       Record.push_back(Arg.ParamNo);
3827       WriteRange(Arg.Use);
3828       Record.push_back(Arg.Calls.size());
3829       for (auto &Call : Arg.Calls) {
3830         Record.push_back(Call.ParamNo);
3831         std::optional<unsigned> ValueID = GetValueID(Call.Callee);
3832         if (!ValueID) {
3833           // If ValueID is unknown we can't drop just this call, we must drop
3834           // entire parameter.
3835           Record.resize(UndoSize);
3836           break;
3837         }
3838         Record.push_back(*ValueID);
3839         WriteRange(Call.Offsets);
3840       }
3841     }
3842     if (!Record.empty())
3843       Stream.EmitRecord(bitc::FS_PARAM_ACCESS, Record);
3844   }
3845 }
3846 
3847 /// Collect type IDs from type tests used by function.
3848 static void
3849 getReferencedTypeIds(FunctionSummary *FS,
3850                      std::set<GlobalValue::GUID> &ReferencedTypeIds) {
3851   if (!FS->type_tests().empty())
3852     for (auto &TT : FS->type_tests())
3853       ReferencedTypeIds.insert(TT);
3854 
3855   auto GetReferencedTypesFromVFuncIdVec =
3856       [&](ArrayRef<FunctionSummary::VFuncId> VFs) {
3857         for (auto &VF : VFs)
3858           ReferencedTypeIds.insert(VF.GUID);
3859       };
3860 
3861   GetReferencedTypesFromVFuncIdVec(FS->type_test_assume_vcalls());
3862   GetReferencedTypesFromVFuncIdVec(FS->type_checked_load_vcalls());
3863 
3864   auto GetReferencedTypesFromConstVCallVec =
3865       [&](ArrayRef<FunctionSummary::ConstVCall> VCs) {
3866         for (auto &VC : VCs)
3867           ReferencedTypeIds.insert(VC.VFunc.GUID);
3868       };
3869 
3870   GetReferencedTypesFromConstVCallVec(FS->type_test_assume_const_vcalls());
3871   GetReferencedTypesFromConstVCallVec(FS->type_checked_load_const_vcalls());
3872 }
3873 
3874 static void writeWholeProgramDevirtResolutionByArg(
3875     SmallVector<uint64_t, 64> &NameVals, const std::vector<uint64_t> &args,
3876     const WholeProgramDevirtResolution::ByArg &ByArg) {
3877   NameVals.push_back(args.size());
3878   llvm::append_range(NameVals, args);
3879 
3880   NameVals.push_back(ByArg.TheKind);
3881   NameVals.push_back(ByArg.Info);
3882   NameVals.push_back(ByArg.Byte);
3883   NameVals.push_back(ByArg.Bit);
3884 }
3885 
3886 static void writeWholeProgramDevirtResolution(
3887     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3888     uint64_t Id, const WholeProgramDevirtResolution &Wpd) {
3889   NameVals.push_back(Id);
3890 
3891   NameVals.push_back(Wpd.TheKind);
3892   NameVals.push_back(StrtabBuilder.add(Wpd.SingleImplName));
3893   NameVals.push_back(Wpd.SingleImplName.size());
3894 
3895   NameVals.push_back(Wpd.ResByArg.size());
3896   for (auto &A : Wpd.ResByArg)
3897     writeWholeProgramDevirtResolutionByArg(NameVals, A.first, A.second);
3898 }
3899 
3900 static void writeTypeIdSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
3901                                      StringTableBuilder &StrtabBuilder,
3902                                      const std::string &Id,
3903                                      const TypeIdSummary &Summary) {
3904   NameVals.push_back(StrtabBuilder.add(Id));
3905   NameVals.push_back(Id.size());
3906 
3907   NameVals.push_back(Summary.TTRes.TheKind);
3908   NameVals.push_back(Summary.TTRes.SizeM1BitWidth);
3909   NameVals.push_back(Summary.TTRes.AlignLog2);
3910   NameVals.push_back(Summary.TTRes.SizeM1);
3911   NameVals.push_back(Summary.TTRes.BitMask);
3912   NameVals.push_back(Summary.TTRes.InlineBits);
3913 
3914   for (auto &W : Summary.WPDRes)
3915     writeWholeProgramDevirtResolution(NameVals, StrtabBuilder, W.first,
3916                                       W.second);
3917 }
3918 
3919 static void writeTypeIdCompatibleVtableSummaryRecord(
3920     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3921     const std::string &Id, const TypeIdCompatibleVtableInfo &Summary,
3922     ValueEnumerator &VE) {
3923   NameVals.push_back(StrtabBuilder.add(Id));
3924   NameVals.push_back(Id.size());
3925 
3926   for (auto &P : Summary) {
3927     NameVals.push_back(P.AddressPointOffset);
3928     NameVals.push_back(VE.getValueID(P.VTableVI.getValue()));
3929   }
3930 }
3931 
3932 static void writeFunctionHeapProfileRecords(
3933     BitstreamWriter &Stream, FunctionSummary *FS, unsigned CallsiteAbbrev,
3934     unsigned AllocAbbrev, bool PerModule,
3935     std::function<unsigned(const ValueInfo &VI)> GetValueID,
3936     std::function<unsigned(unsigned)> GetStackIndex) {
3937   SmallVector<uint64_t> Record;
3938 
3939   for (auto &CI : FS->callsites()) {
3940     Record.clear();
3941     // Per module callsite clones should always have a single entry of
3942     // value 0.
3943     assert(!PerModule || (CI.Clones.size() == 1 && CI.Clones[0] == 0));
3944     Record.push_back(GetValueID(CI.Callee));
3945     if (!PerModule) {
3946       Record.push_back(CI.StackIdIndices.size());
3947       Record.push_back(CI.Clones.size());
3948     }
3949     for (auto Id : CI.StackIdIndices)
3950       Record.push_back(GetStackIndex(Id));
3951     if (!PerModule) {
3952       for (auto V : CI.Clones)
3953         Record.push_back(V);
3954     }
3955     Stream.EmitRecord(PerModule ? bitc::FS_PERMODULE_CALLSITE_INFO
3956                                 : bitc::FS_COMBINED_CALLSITE_INFO,
3957                       Record, CallsiteAbbrev);
3958   }
3959 
3960   for (auto &AI : FS->allocs()) {
3961     Record.clear();
3962     // Per module alloc versions should always have a single entry of
3963     // value 0.
3964     assert(!PerModule || (AI.Versions.size() == 1 && AI.Versions[0] == 0));
3965     if (!PerModule) {
3966       Record.push_back(AI.MIBs.size());
3967       Record.push_back(AI.Versions.size());
3968     }
3969     for (auto &MIB : AI.MIBs) {
3970       Record.push_back((uint8_t)MIB.AllocType);
3971       Record.push_back(MIB.StackIdIndices.size());
3972       for (auto Id : MIB.StackIdIndices)
3973         Record.push_back(GetStackIndex(Id));
3974     }
3975     if (!PerModule) {
3976       for (auto V : AI.Versions)
3977         Record.push_back(V);
3978     }
3979     Stream.EmitRecord(PerModule ? bitc::FS_PERMODULE_ALLOC_INFO
3980                                 : bitc::FS_COMBINED_ALLOC_INFO,
3981                       Record, AllocAbbrev);
3982   }
3983 }
3984 
3985 // Helper to emit a single function summary record.
3986 void ModuleBitcodeWriterBase::writePerModuleFunctionSummaryRecord(
3987     SmallVector<uint64_t, 64> &NameVals, GlobalValueSummary *Summary,
3988     unsigned ValueID, unsigned FSCallsAbbrev, unsigned FSCallsProfileAbbrev,
3989     unsigned CallsiteAbbrev, unsigned AllocAbbrev, const Function &F) {
3990   NameVals.push_back(ValueID);
3991 
3992   FunctionSummary *FS = cast<FunctionSummary>(Summary);
3993 
3994   writeFunctionTypeMetadataRecords(
3995       Stream, FS, [&](const ValueInfo &VI) -> std::optional<unsigned> {
3996         return {VE.getValueID(VI.getValue())};
3997       });
3998 
3999   writeFunctionHeapProfileRecords(
4000       Stream, FS, CallsiteAbbrev, AllocAbbrev,
4001       /*PerModule*/ true,
4002       /*GetValueId*/ [&](const ValueInfo &VI) { return getValueId(VI); },
4003       /*GetStackIndex*/ [&](unsigned I) { return I; });
4004 
4005   auto SpecialRefCnts = FS->specialRefCounts();
4006   NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
4007   NameVals.push_back(FS->instCount());
4008   NameVals.push_back(getEncodedFFlags(FS->fflags()));
4009   NameVals.push_back(FS->refs().size());
4010   NameVals.push_back(SpecialRefCnts.first);  // rorefcnt
4011   NameVals.push_back(SpecialRefCnts.second); // worefcnt
4012 
4013   for (auto &RI : FS->refs())
4014     NameVals.push_back(VE.getValueID(RI.getValue()));
4015 
4016   bool HasProfileData =
4017       F.hasProfileData() || ForceSummaryEdgesCold != FunctionSummary::FSHT_None;
4018   for (auto &ECI : FS->calls()) {
4019     NameVals.push_back(getValueId(ECI.first));
4020     if (HasProfileData)
4021       NameVals.push_back(static_cast<uint8_t>(ECI.second.Hotness));
4022     else if (WriteRelBFToSummary)
4023       NameVals.push_back(ECI.second.RelBlockFreq);
4024   }
4025 
4026   unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
4027   unsigned Code =
4028       (HasProfileData ? bitc::FS_PERMODULE_PROFILE
4029                       : (WriteRelBFToSummary ? bitc::FS_PERMODULE_RELBF
4030                                              : bitc::FS_PERMODULE));
4031 
4032   // Emit the finished record.
4033   Stream.EmitRecord(Code, NameVals, FSAbbrev);
4034   NameVals.clear();
4035 }
4036 
4037 // Collect the global value references in the given variable's initializer,
4038 // and emit them in a summary record.
4039 void ModuleBitcodeWriterBase::writeModuleLevelReferences(
4040     const GlobalVariable &V, SmallVector<uint64_t, 64> &NameVals,
4041     unsigned FSModRefsAbbrev, unsigned FSModVTableRefsAbbrev) {
4042   auto VI = Index->getValueInfo(V.getGUID());
4043   if (!VI || VI.getSummaryList().empty()) {
4044     // Only declarations should not have a summary (a declaration might however
4045     // have a summary if the def was in module level asm).
4046     assert(V.isDeclaration());
4047     return;
4048   }
4049   auto *Summary = VI.getSummaryList()[0].get();
4050   NameVals.push_back(VE.getValueID(&V));
4051   GlobalVarSummary *VS = cast<GlobalVarSummary>(Summary);
4052   NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
4053   NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
4054 
4055   auto VTableFuncs = VS->vTableFuncs();
4056   if (!VTableFuncs.empty())
4057     NameVals.push_back(VS->refs().size());
4058 
4059   unsigned SizeBeforeRefs = NameVals.size();
4060   for (auto &RI : VS->refs())
4061     NameVals.push_back(VE.getValueID(RI.getValue()));
4062   // Sort the refs for determinism output, the vector returned by FS->refs() has
4063   // been initialized from a DenseSet.
4064   llvm::sort(drop_begin(NameVals, SizeBeforeRefs));
4065 
4066   if (VTableFuncs.empty())
4067     Stream.EmitRecord(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS, NameVals,
4068                       FSModRefsAbbrev);
4069   else {
4070     // VTableFuncs pairs should already be sorted by offset.
4071     for (auto &P : VTableFuncs) {
4072       NameVals.push_back(VE.getValueID(P.FuncVI.getValue()));
4073       NameVals.push_back(P.VTableOffset);
4074     }
4075 
4076     Stream.EmitRecord(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS, NameVals,
4077                       FSModVTableRefsAbbrev);
4078   }
4079   NameVals.clear();
4080 }
4081 
4082 /// Emit the per-module summary section alongside the rest of
4083 /// the module's bitcode.
4084 void ModuleBitcodeWriterBase::writePerModuleGlobalValueSummary() {
4085   // By default we compile with ThinLTO if the module has a summary, but the
4086   // client can request full LTO with a module flag.
4087   bool IsThinLTO = true;
4088   if (auto *MD =
4089           mdconst::extract_or_null<ConstantInt>(M.getModuleFlag("ThinLTO")))
4090     IsThinLTO = MD->getZExtValue();
4091   Stream.EnterSubblock(IsThinLTO ? bitc::GLOBALVAL_SUMMARY_BLOCK_ID
4092                                  : bitc::FULL_LTO_GLOBALVAL_SUMMARY_BLOCK_ID,
4093                        4);
4094 
4095   Stream.EmitRecord(
4096       bitc::FS_VERSION,
4097       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
4098 
4099   // Write the index flags.
4100   uint64_t Flags = 0;
4101   // Bits 1-3 are set only in the combined index, skip them.
4102   if (Index->enableSplitLTOUnit())
4103     Flags |= 0x8;
4104   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Flags});
4105 
4106   if (Index->begin() == Index->end()) {
4107     Stream.ExitBlock();
4108     return;
4109   }
4110 
4111   for (const auto &GVI : valueIds()) {
4112     Stream.EmitRecord(bitc::FS_VALUE_GUID,
4113                       ArrayRef<uint64_t>{GVI.second, GVI.first});
4114   }
4115 
4116   if (!Index->stackIds().empty()) {
4117     auto StackIdAbbv = std::make_shared<BitCodeAbbrev>();
4118     StackIdAbbv->Add(BitCodeAbbrevOp(bitc::FS_STACK_IDS));
4119     // numids x stackid
4120     StackIdAbbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4121     StackIdAbbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4122     unsigned StackIdAbbvId = Stream.EmitAbbrev(std::move(StackIdAbbv));
4123     Stream.EmitRecord(bitc::FS_STACK_IDS, Index->stackIds(), StackIdAbbvId);
4124   }
4125 
4126   // Abbrev for FS_PERMODULE_PROFILE.
4127   auto Abbv = std::make_shared<BitCodeAbbrev>();
4128   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_PROFILE));
4129   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4130   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4131   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4132   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4133   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4134   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4135   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4136   // numrefs x valueid, n x (valueid, hotness)
4137   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4138   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4139   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4140 
4141   // Abbrev for FS_PERMODULE or FS_PERMODULE_RELBF.
4142   Abbv = std::make_shared<BitCodeAbbrev>();
4143   if (WriteRelBFToSummary)
4144     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_RELBF));
4145   else
4146     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE));
4147   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4148   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4149   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4150   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4151   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4152   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4153   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4154   // numrefs x valueid, n x (valueid [, rel_block_freq])
4155   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4156   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4157   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4158 
4159   // Abbrev for FS_PERMODULE_GLOBALVAR_INIT_REFS.
4160   Abbv = std::make_shared<BitCodeAbbrev>();
4161   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS));
4162   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
4163   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
4164   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));  // valueids
4165   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4166   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4167 
4168   // Abbrev for FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS.
4169   Abbv = std::make_shared<BitCodeAbbrev>();
4170   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS));
4171   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
4172   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
4173   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numrefs
4174   // numrefs x valueid, n x (valueid , offset)
4175   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4176   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4177   unsigned FSModVTableRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4178 
4179   // Abbrev for FS_ALIAS.
4180   Abbv = std::make_shared<BitCodeAbbrev>();
4181   Abbv->Add(BitCodeAbbrevOp(bitc::FS_ALIAS));
4182   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4183   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4184   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4185   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4186 
4187   // Abbrev for FS_TYPE_ID_METADATA
4188   Abbv = std::make_shared<BitCodeAbbrev>();
4189   Abbv->Add(BitCodeAbbrevOp(bitc::FS_TYPE_ID_METADATA));
4190   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid strtab index
4191   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid length
4192   // n x (valueid , offset)
4193   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4194   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4195   unsigned TypeIdCompatibleVtableAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4196 
4197   Abbv = std::make_shared<BitCodeAbbrev>();
4198   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_CALLSITE_INFO));
4199   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
4200   // n x stackidindex
4201   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4202   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4203   unsigned CallsiteAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4204 
4205   Abbv = std::make_shared<BitCodeAbbrev>();
4206   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_ALLOC_INFO));
4207   // n x (alloc type, numstackids, numstackids x stackidindex)
4208   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4209   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4210   unsigned AllocAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4211 
4212   SmallVector<uint64_t, 64> NameVals;
4213   // Iterate over the list of functions instead of the Index to
4214   // ensure the ordering is stable.
4215   for (const Function &F : M) {
4216     // Summary emission does not support anonymous functions, they have to
4217     // renamed using the anonymous function renaming pass.
4218     if (!F.hasName())
4219       report_fatal_error("Unexpected anonymous function when writing summary");
4220 
4221     ValueInfo VI = Index->getValueInfo(F.getGUID());
4222     if (!VI || VI.getSummaryList().empty()) {
4223       // Only declarations should not have a summary (a declaration might
4224       // however have a summary if the def was in module level asm).
4225       assert(F.isDeclaration());
4226       continue;
4227     }
4228     auto *Summary = VI.getSummaryList()[0].get();
4229     writePerModuleFunctionSummaryRecord(NameVals, Summary, VE.getValueID(&F),
4230                                         FSCallsAbbrev, FSCallsProfileAbbrev,
4231                                         CallsiteAbbrev, AllocAbbrev, F);
4232   }
4233 
4234   // Capture references from GlobalVariable initializers, which are outside
4235   // of a function scope.
4236   for (const GlobalVariable &G : M.globals())
4237     writeModuleLevelReferences(G, NameVals, FSModRefsAbbrev,
4238                                FSModVTableRefsAbbrev);
4239 
4240   for (const GlobalAlias &A : M.aliases()) {
4241     auto *Aliasee = A.getAliaseeObject();
4242     // Skip ifunc and nameless functions which don't have an entry in the
4243     // summary.
4244     if (!Aliasee->hasName() || isa<GlobalIFunc>(Aliasee))
4245       continue;
4246     auto AliasId = VE.getValueID(&A);
4247     auto AliaseeId = VE.getValueID(Aliasee);
4248     NameVals.push_back(AliasId);
4249     auto *Summary = Index->getGlobalValueSummary(A);
4250     AliasSummary *AS = cast<AliasSummary>(Summary);
4251     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
4252     NameVals.push_back(AliaseeId);
4253     Stream.EmitRecord(bitc::FS_ALIAS, NameVals, FSAliasAbbrev);
4254     NameVals.clear();
4255   }
4256 
4257   for (auto &S : Index->typeIdCompatibleVtableMap()) {
4258     writeTypeIdCompatibleVtableSummaryRecord(NameVals, StrtabBuilder, S.first,
4259                                              S.second, VE);
4260     Stream.EmitRecord(bitc::FS_TYPE_ID_METADATA, NameVals,
4261                       TypeIdCompatibleVtableAbbrev);
4262     NameVals.clear();
4263   }
4264 
4265   Stream.EmitRecord(bitc::FS_BLOCK_COUNT,
4266                     ArrayRef<uint64_t>{Index->getBlockCount()});
4267 
4268   Stream.ExitBlock();
4269 }
4270 
4271 /// Emit the combined summary section into the combined index file.
4272 void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
4273   Stream.EnterSubblock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID, 4);
4274   Stream.EmitRecord(
4275       bitc::FS_VERSION,
4276       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
4277 
4278   // Write the index flags.
4279   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Index.getFlags()});
4280 
4281   for (const auto &GVI : valueIds()) {
4282     Stream.EmitRecord(bitc::FS_VALUE_GUID,
4283                       ArrayRef<uint64_t>{GVI.second, GVI.first});
4284   }
4285 
4286   if (!StackIdIndices.empty()) {
4287     auto StackIdAbbv = std::make_shared<BitCodeAbbrev>();
4288     StackIdAbbv->Add(BitCodeAbbrevOp(bitc::FS_STACK_IDS));
4289     // numids x stackid
4290     StackIdAbbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4291     StackIdAbbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4292     unsigned StackIdAbbvId = Stream.EmitAbbrev(std::move(StackIdAbbv));
4293     // Write the stack ids used by this index, which will be a subset of those in
4294     // the full index in the case of distributed indexes.
4295     std::vector<uint64_t> StackIds;
4296     for (auto &I : StackIdIndices)
4297       StackIds.push_back(Index.getStackIdAtIndex(I));
4298     Stream.EmitRecord(bitc::FS_STACK_IDS, StackIds, StackIdAbbvId);
4299   }
4300 
4301   // Abbrev for FS_COMBINED.
4302   auto Abbv = std::make_shared<BitCodeAbbrev>();
4303   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED));
4304   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4305   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4306   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4307   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4308   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4309   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
4310   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4311   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4312   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4313   // numrefs x valueid, n x (valueid)
4314   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4315   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4316   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4317 
4318   // Abbrev for FS_COMBINED_PROFILE.
4319   Abbv = std::make_shared<BitCodeAbbrev>();
4320   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_PROFILE));
4321   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4322   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4323   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4324   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4325   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4326   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
4327   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4328   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4329   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4330   // numrefs x valueid, n x (valueid, hotness)
4331   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4332   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4333   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4334 
4335   // Abbrev for FS_COMBINED_GLOBALVAR_INIT_REFS.
4336   Abbv = std::make_shared<BitCodeAbbrev>();
4337   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS));
4338   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4339   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4340   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4341   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));    // valueids
4342   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4343   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4344 
4345   // Abbrev for FS_COMBINED_ALIAS.
4346   Abbv = std::make_shared<BitCodeAbbrev>();
4347   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_ALIAS));
4348   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4349   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4350   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4351   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4352   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4353 
4354   Abbv = std::make_shared<BitCodeAbbrev>();
4355   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_CALLSITE_INFO));
4356   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
4357   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numstackindices
4358   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numver
4359   // numstackindices x stackidindex, numver x version
4360   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4361   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4362   unsigned CallsiteAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4363 
4364   Abbv = std::make_shared<BitCodeAbbrev>();
4365   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_ALLOC_INFO));
4366   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // nummib
4367   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numver
4368   // nummib x (alloc type, numstackids, numstackids x stackidindex),
4369   // numver x version
4370   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4371   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4372   unsigned AllocAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4373 
4374   // The aliases are emitted as a post-pass, and will point to the value
4375   // id of the aliasee. Save them in a vector for post-processing.
4376   SmallVector<AliasSummary *, 64> Aliases;
4377 
4378   // Save the value id for each summary for alias emission.
4379   DenseMap<const GlobalValueSummary *, unsigned> SummaryToValueIdMap;
4380 
4381   SmallVector<uint64_t, 64> NameVals;
4382 
4383   // Set that will be populated during call to writeFunctionTypeMetadataRecords
4384   // with the type ids referenced by this index file.
4385   std::set<GlobalValue::GUID> ReferencedTypeIds;
4386 
4387   // For local linkage, we also emit the original name separately
4388   // immediately after the record.
4389   auto MaybeEmitOriginalName = [&](GlobalValueSummary &S) {
4390     // We don't need to emit the original name if we are writing the index for
4391     // distributed backends (in which case ModuleToSummariesForIndex is
4392     // non-null). The original name is only needed during the thin link, since
4393     // for SamplePGO the indirect call targets for local functions have
4394     // have the original name annotated in profile.
4395     // Continue to emit it when writing out the entire combined index, which is
4396     // used in testing the thin link via llvm-lto.
4397     if (ModuleToSummariesForIndex || !GlobalValue::isLocalLinkage(S.linkage()))
4398       return;
4399     NameVals.push_back(S.getOriginalName());
4400     Stream.EmitRecord(bitc::FS_COMBINED_ORIGINAL_NAME, NameVals);
4401     NameVals.clear();
4402   };
4403 
4404   std::set<GlobalValue::GUID> DefOrUseGUIDs;
4405   forEachSummary([&](GVInfo I, bool IsAliasee) {
4406     GlobalValueSummary *S = I.second;
4407     assert(S);
4408     DefOrUseGUIDs.insert(I.first);
4409     for (const ValueInfo &VI : S->refs())
4410       DefOrUseGUIDs.insert(VI.getGUID());
4411 
4412     auto ValueId = getValueId(I.first);
4413     assert(ValueId);
4414     SummaryToValueIdMap[S] = *ValueId;
4415 
4416     // If this is invoked for an aliasee, we want to record the above
4417     // mapping, but then not emit a summary entry (if the aliasee is
4418     // to be imported, we will invoke this separately with IsAliasee=false).
4419     if (IsAliasee)
4420       return;
4421 
4422     if (auto *AS = dyn_cast<AliasSummary>(S)) {
4423       // Will process aliases as a post-pass because the reader wants all
4424       // global to be loaded first.
4425       Aliases.push_back(AS);
4426       return;
4427     }
4428 
4429     if (auto *VS = dyn_cast<GlobalVarSummary>(S)) {
4430       NameVals.push_back(*ValueId);
4431       NameVals.push_back(Index.getModuleId(VS->modulePath()));
4432       NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
4433       NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
4434       for (auto &RI : VS->refs()) {
4435         auto RefValueId = getValueId(RI.getGUID());
4436         if (!RefValueId)
4437           continue;
4438         NameVals.push_back(*RefValueId);
4439       }
4440 
4441       // Emit the finished record.
4442       Stream.EmitRecord(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS, NameVals,
4443                         FSModRefsAbbrev);
4444       NameVals.clear();
4445       MaybeEmitOriginalName(*S);
4446       return;
4447     }
4448 
4449     auto GetValueId = [&](const ValueInfo &VI) -> std::optional<unsigned> {
4450       if (!VI)
4451         return std::nullopt;
4452       return getValueId(VI.getGUID());
4453     };
4454 
4455     auto *FS = cast<FunctionSummary>(S);
4456     writeFunctionTypeMetadataRecords(Stream, FS, GetValueId);
4457     getReferencedTypeIds(FS, ReferencedTypeIds);
4458 
4459     writeFunctionHeapProfileRecords(
4460         Stream, FS, CallsiteAbbrev, AllocAbbrev,
4461         /*PerModule*/ false,
4462         /*GetValueId*/ [&](const ValueInfo &VI) -> unsigned {
4463           std::optional<unsigned> ValueID = GetValueId(VI);
4464           // This can happen in shared index files for distributed ThinLTO if
4465           // the callee function summary is not included. Record 0 which we
4466           // will have to deal with conservatively when doing any kind of
4467           // validation in the ThinLTO backends.
4468           if (!ValueID)
4469             return 0;
4470           return *ValueID;
4471         },
4472         /*GetStackIndex*/ [&](unsigned I) {
4473           // Get the corresponding index into the list of StackIdIndices
4474           // actually being written for this combined index (which may be a
4475           // subset in the case of distributed indexes).
4476           auto Lower = llvm::lower_bound(StackIdIndices, I);
4477           return std::distance(StackIdIndices.begin(), Lower);
4478         });
4479 
4480     NameVals.push_back(*ValueId);
4481     NameVals.push_back(Index.getModuleId(FS->modulePath()));
4482     NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
4483     NameVals.push_back(FS->instCount());
4484     NameVals.push_back(getEncodedFFlags(FS->fflags()));
4485     NameVals.push_back(FS->entryCount());
4486 
4487     // Fill in below
4488     NameVals.push_back(0); // numrefs
4489     NameVals.push_back(0); // rorefcnt
4490     NameVals.push_back(0); // worefcnt
4491 
4492     unsigned Count = 0, RORefCnt = 0, WORefCnt = 0;
4493     for (auto &RI : FS->refs()) {
4494       auto RefValueId = getValueId(RI.getGUID());
4495       if (!RefValueId)
4496         continue;
4497       NameVals.push_back(*RefValueId);
4498       if (RI.isReadOnly())
4499         RORefCnt++;
4500       else if (RI.isWriteOnly())
4501         WORefCnt++;
4502       Count++;
4503     }
4504     NameVals[6] = Count;
4505     NameVals[7] = RORefCnt;
4506     NameVals[8] = WORefCnt;
4507 
4508     bool HasProfileData = false;
4509     for (auto &EI : FS->calls()) {
4510       HasProfileData |=
4511           EI.second.getHotness() != CalleeInfo::HotnessType::Unknown;
4512       if (HasProfileData)
4513         break;
4514     }
4515 
4516     for (auto &EI : FS->calls()) {
4517       // If this GUID doesn't have a value id, it doesn't have a function
4518       // summary and we don't need to record any calls to it.
4519       std::optional<unsigned> CallValueId = GetValueId(EI.first);
4520       if (!CallValueId)
4521         continue;
4522       NameVals.push_back(*CallValueId);
4523       if (HasProfileData)
4524         NameVals.push_back(static_cast<uint8_t>(EI.second.Hotness));
4525     }
4526 
4527     unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
4528     unsigned Code =
4529         (HasProfileData ? bitc::FS_COMBINED_PROFILE : bitc::FS_COMBINED);
4530 
4531     // Emit the finished record.
4532     Stream.EmitRecord(Code, NameVals, FSAbbrev);
4533     NameVals.clear();
4534     MaybeEmitOriginalName(*S);
4535   });
4536 
4537   for (auto *AS : Aliases) {
4538     auto AliasValueId = SummaryToValueIdMap[AS];
4539     assert(AliasValueId);
4540     NameVals.push_back(AliasValueId);
4541     NameVals.push_back(Index.getModuleId(AS->modulePath()));
4542     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
4543     auto AliaseeValueId = SummaryToValueIdMap[&AS->getAliasee()];
4544     assert(AliaseeValueId);
4545     NameVals.push_back(AliaseeValueId);
4546 
4547     // Emit the finished record.
4548     Stream.EmitRecord(bitc::FS_COMBINED_ALIAS, NameVals, FSAliasAbbrev);
4549     NameVals.clear();
4550     MaybeEmitOriginalName(*AS);
4551 
4552     if (auto *FS = dyn_cast<FunctionSummary>(&AS->getAliasee()))
4553       getReferencedTypeIds(FS, ReferencedTypeIds);
4554   }
4555 
4556   if (!Index.cfiFunctionDefs().empty()) {
4557     for (auto &S : Index.cfiFunctionDefs()) {
4558       if (DefOrUseGUIDs.count(
4559               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4560         NameVals.push_back(StrtabBuilder.add(S));
4561         NameVals.push_back(S.size());
4562       }
4563     }
4564     if (!NameVals.empty()) {
4565       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DEFS, NameVals);
4566       NameVals.clear();
4567     }
4568   }
4569 
4570   if (!Index.cfiFunctionDecls().empty()) {
4571     for (auto &S : Index.cfiFunctionDecls()) {
4572       if (DefOrUseGUIDs.count(
4573               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4574         NameVals.push_back(StrtabBuilder.add(S));
4575         NameVals.push_back(S.size());
4576       }
4577     }
4578     if (!NameVals.empty()) {
4579       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DECLS, NameVals);
4580       NameVals.clear();
4581     }
4582   }
4583 
4584   // Walk the GUIDs that were referenced, and write the
4585   // corresponding type id records.
4586   for (auto &T : ReferencedTypeIds) {
4587     auto TidIter = Index.typeIds().equal_range(T);
4588     for (auto It = TidIter.first; It != TidIter.second; ++It) {
4589       writeTypeIdSummaryRecord(NameVals, StrtabBuilder, It->second.first,
4590                                It->second.second);
4591       Stream.EmitRecord(bitc::FS_TYPE_ID, NameVals);
4592       NameVals.clear();
4593     }
4594   }
4595 
4596   Stream.EmitRecord(bitc::FS_BLOCK_COUNT,
4597                     ArrayRef<uint64_t>{Index.getBlockCount()});
4598 
4599   Stream.ExitBlock();
4600 }
4601 
4602 /// Create the "IDENTIFICATION_BLOCK_ID" containing a single string with the
4603 /// current llvm version, and a record for the epoch number.
4604 static void writeIdentificationBlock(BitstreamWriter &Stream) {
4605   Stream.EnterSubblock(bitc::IDENTIFICATION_BLOCK_ID, 5);
4606 
4607   // Write the "user readable" string identifying the bitcode producer
4608   auto Abbv = std::make_shared<BitCodeAbbrev>();
4609   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_STRING));
4610   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4611   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
4612   auto StringAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4613   writeStringRecord(Stream, bitc::IDENTIFICATION_CODE_STRING,
4614                     "LLVM" LLVM_VERSION_STRING, StringAbbrev);
4615 
4616   // Write the epoch version
4617   Abbv = std::make_shared<BitCodeAbbrev>();
4618   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_EPOCH));
4619   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
4620   auto EpochAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4621   constexpr std::array<unsigned, 1> Vals = {{bitc::BITCODE_CURRENT_EPOCH}};
4622   Stream.EmitRecord(bitc::IDENTIFICATION_CODE_EPOCH, Vals, EpochAbbrev);
4623   Stream.ExitBlock();
4624 }
4625 
4626 void ModuleBitcodeWriter::writeModuleHash(size_t BlockStartPos) {
4627   // Emit the module's hash.
4628   // MODULE_CODE_HASH: [5*i32]
4629   if (GenerateHash) {
4630     uint32_t Vals[5];
4631     Hasher.update(ArrayRef<uint8_t>((const uint8_t *)&(Buffer)[BlockStartPos],
4632                                     Buffer.size() - BlockStartPos));
4633     std::array<uint8_t, 20> Hash = Hasher.result();
4634     for (int Pos = 0; Pos < 20; Pos += 4) {
4635       Vals[Pos / 4] = support::endian::read32be(Hash.data() + Pos);
4636     }
4637 
4638     // Emit the finished record.
4639     Stream.EmitRecord(bitc::MODULE_CODE_HASH, Vals);
4640 
4641     if (ModHash)
4642       // Save the written hash value.
4643       llvm::copy(Vals, std::begin(*ModHash));
4644   }
4645 }
4646 
4647 void ModuleBitcodeWriter::write() {
4648   writeIdentificationBlock(Stream);
4649 
4650   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4651   size_t BlockStartPos = Buffer.size();
4652 
4653   writeModuleVersion();
4654 
4655   // Emit blockinfo, which defines the standard abbreviations etc.
4656   writeBlockInfo();
4657 
4658   // Emit information describing all of the types in the module.
4659   writeTypeTable();
4660 
4661   // Emit information about attribute groups.
4662   writeAttributeGroupTable();
4663 
4664   // Emit information about parameter attributes.
4665   writeAttributeTable();
4666 
4667   writeComdats();
4668 
4669   // Emit top-level description of module, including target triple, inline asm,
4670   // descriptors for global variables, and function prototype info.
4671   writeModuleInfo();
4672 
4673   // Emit constants.
4674   writeModuleConstants();
4675 
4676   // Emit metadata kind names.
4677   writeModuleMetadataKinds();
4678 
4679   // Emit metadata.
4680   writeModuleMetadata();
4681 
4682   // Emit module-level use-lists.
4683   if (VE.shouldPreserveUseListOrder())
4684     writeUseListBlock(nullptr);
4685 
4686   writeOperandBundleTags();
4687   writeSyncScopeNames();
4688 
4689   // Emit function bodies.
4690   DenseMap<const Function *, uint64_t> FunctionToBitcodeIndex;
4691   for (const Function &F : M)
4692     if (!F.isDeclaration())
4693       writeFunction(F, FunctionToBitcodeIndex);
4694 
4695   // Need to write after the above call to WriteFunction which populates
4696   // the summary information in the index.
4697   if (Index)
4698     writePerModuleGlobalValueSummary();
4699 
4700   writeGlobalValueSymbolTable(FunctionToBitcodeIndex);
4701 
4702   writeModuleHash(BlockStartPos);
4703 
4704   Stream.ExitBlock();
4705 }
4706 
4707 static void writeInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
4708                                uint32_t &Position) {
4709   support::endian::write32le(&Buffer[Position], Value);
4710   Position += 4;
4711 }
4712 
4713 /// If generating a bc file on darwin, we have to emit a
4714 /// header and trailer to make it compatible with the system archiver.  To do
4715 /// this we emit the following header, and then emit a trailer that pads the
4716 /// file out to be a multiple of 16 bytes.
4717 ///
4718 /// struct bc_header {
4719 ///   uint32_t Magic;         // 0x0B17C0DE
4720 ///   uint32_t Version;       // Version, currently always 0.
4721 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
4722 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
4723 ///   uint32_t CPUType;       // CPU specifier.
4724 ///   ... potentially more later ...
4725 /// };
4726 static void emitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
4727                                          const Triple &TT) {
4728   unsigned CPUType = ~0U;
4729 
4730   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
4731   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
4732   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
4733   // specific constants here because they are implicitly part of the Darwin ABI.
4734   enum {
4735     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
4736     DARWIN_CPU_TYPE_X86        = 7,
4737     DARWIN_CPU_TYPE_ARM        = 12,
4738     DARWIN_CPU_TYPE_POWERPC    = 18
4739   };
4740 
4741   Triple::ArchType Arch = TT.getArch();
4742   if (Arch == Triple::x86_64)
4743     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
4744   else if (Arch == Triple::x86)
4745     CPUType = DARWIN_CPU_TYPE_X86;
4746   else if (Arch == Triple::ppc)
4747     CPUType = DARWIN_CPU_TYPE_POWERPC;
4748   else if (Arch == Triple::ppc64)
4749     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
4750   else if (Arch == Triple::arm || Arch == Triple::thumb)
4751     CPUType = DARWIN_CPU_TYPE_ARM;
4752 
4753   // Traditional Bitcode starts after header.
4754   assert(Buffer.size() >= BWH_HeaderSize &&
4755          "Expected header size to be reserved");
4756   unsigned BCOffset = BWH_HeaderSize;
4757   unsigned BCSize = Buffer.size() - BWH_HeaderSize;
4758 
4759   // Write the magic and version.
4760   unsigned Position = 0;
4761   writeInt32ToBuffer(0x0B17C0DE, Buffer, Position);
4762   writeInt32ToBuffer(0, Buffer, Position); // Version.
4763   writeInt32ToBuffer(BCOffset, Buffer, Position);
4764   writeInt32ToBuffer(BCSize, Buffer, Position);
4765   writeInt32ToBuffer(CPUType, Buffer, Position);
4766 
4767   // If the file is not a multiple of 16 bytes, insert dummy padding.
4768   while (Buffer.size() & 15)
4769     Buffer.push_back(0);
4770 }
4771 
4772 /// Helper to write the header common to all bitcode files.
4773 static void writeBitcodeHeader(BitstreamWriter &Stream) {
4774   // Emit the file header.
4775   Stream.Emit((unsigned)'B', 8);
4776   Stream.Emit((unsigned)'C', 8);
4777   Stream.Emit(0x0, 4);
4778   Stream.Emit(0xC, 4);
4779   Stream.Emit(0xE, 4);
4780   Stream.Emit(0xD, 4);
4781 }
4782 
4783 BitcodeWriter::BitcodeWriter(SmallVectorImpl<char> &Buffer, raw_fd_stream *FS)
4784     : Buffer(Buffer), Stream(new BitstreamWriter(Buffer, FS, FlushThreshold)) {
4785   writeBitcodeHeader(*Stream);
4786 }
4787 
4788 BitcodeWriter::~BitcodeWriter() { assert(WroteStrtab); }
4789 
4790 void BitcodeWriter::writeBlob(unsigned Block, unsigned Record, StringRef Blob) {
4791   Stream->EnterSubblock(Block, 3);
4792 
4793   auto Abbv = std::make_shared<BitCodeAbbrev>();
4794   Abbv->Add(BitCodeAbbrevOp(Record));
4795   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
4796   auto AbbrevNo = Stream->EmitAbbrev(std::move(Abbv));
4797 
4798   Stream->EmitRecordWithBlob(AbbrevNo, ArrayRef<uint64_t>{Record}, Blob);
4799 
4800   Stream->ExitBlock();
4801 }
4802 
4803 void BitcodeWriter::writeSymtab() {
4804   assert(!WroteStrtab && !WroteSymtab);
4805 
4806   // If any module has module-level inline asm, we will require a registered asm
4807   // parser for the target so that we can create an accurate symbol table for
4808   // the module.
4809   for (Module *M : Mods) {
4810     if (M->getModuleInlineAsm().empty())
4811       continue;
4812 
4813     std::string Err;
4814     const Triple TT(M->getTargetTriple());
4815     const Target *T = TargetRegistry::lookupTarget(TT.str(), Err);
4816     if (!T || !T->hasMCAsmParser())
4817       return;
4818   }
4819 
4820   WroteSymtab = true;
4821   SmallVector<char, 0> Symtab;
4822   // The irsymtab::build function may be unable to create a symbol table if the
4823   // module is malformed (e.g. it contains an invalid alias). Writing a symbol
4824   // table is not required for correctness, but we still want to be able to
4825   // write malformed modules to bitcode files, so swallow the error.
4826   if (Error E = irsymtab::build(Mods, Symtab, StrtabBuilder, Alloc)) {
4827     consumeError(std::move(E));
4828     return;
4829   }
4830 
4831   writeBlob(bitc::SYMTAB_BLOCK_ID, bitc::SYMTAB_BLOB,
4832             {Symtab.data(), Symtab.size()});
4833 }
4834 
4835 void BitcodeWriter::writeStrtab() {
4836   assert(!WroteStrtab);
4837 
4838   std::vector<char> Strtab;
4839   StrtabBuilder.finalizeInOrder();
4840   Strtab.resize(StrtabBuilder.getSize());
4841   StrtabBuilder.write((uint8_t *)Strtab.data());
4842 
4843   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB,
4844             {Strtab.data(), Strtab.size()});
4845 
4846   WroteStrtab = true;
4847 }
4848 
4849 void BitcodeWriter::copyStrtab(StringRef Strtab) {
4850   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB, Strtab);
4851   WroteStrtab = true;
4852 }
4853 
4854 void BitcodeWriter::writeModule(const Module &M,
4855                                 bool ShouldPreserveUseListOrder,
4856                                 const ModuleSummaryIndex *Index,
4857                                 bool GenerateHash, ModuleHash *ModHash) {
4858   assert(!WroteStrtab);
4859 
4860   // The Mods vector is used by irsymtab::build, which requires non-const
4861   // Modules in case it needs to materialize metadata. But the bitcode writer
4862   // requires that the module is materialized, so we can cast to non-const here,
4863   // after checking that it is in fact materialized.
4864   assert(M.isMaterialized());
4865   Mods.push_back(const_cast<Module *>(&M));
4866 
4867   ModuleBitcodeWriter ModuleWriter(M, Buffer, StrtabBuilder, *Stream,
4868                                    ShouldPreserveUseListOrder, Index,
4869                                    GenerateHash, ModHash);
4870   ModuleWriter.write();
4871 }
4872 
4873 void BitcodeWriter::writeIndex(
4874     const ModuleSummaryIndex *Index,
4875     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4876   IndexBitcodeWriter IndexWriter(*Stream, StrtabBuilder, *Index,
4877                                  ModuleToSummariesForIndex);
4878   IndexWriter.write();
4879 }
4880 
4881 /// Write the specified module to the specified output stream.
4882 void llvm::WriteBitcodeToFile(const Module &M, raw_ostream &Out,
4883                               bool ShouldPreserveUseListOrder,
4884                               const ModuleSummaryIndex *Index,
4885                               bool GenerateHash, ModuleHash *ModHash) {
4886   SmallVector<char, 0> Buffer;
4887   Buffer.reserve(256*1024);
4888 
4889   // If this is darwin or another generic macho target, reserve space for the
4890   // header.
4891   Triple TT(M.getTargetTriple());
4892   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4893     Buffer.insert(Buffer.begin(), BWH_HeaderSize, 0);
4894 
4895   BitcodeWriter Writer(Buffer, dyn_cast<raw_fd_stream>(&Out));
4896   Writer.writeModule(M, ShouldPreserveUseListOrder, Index, GenerateHash,
4897                      ModHash);
4898   Writer.writeSymtab();
4899   Writer.writeStrtab();
4900 
4901   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4902     emitDarwinBCHeaderAndTrailer(Buffer, TT);
4903 
4904   // Write the generated bitstream to "Out".
4905   if (!Buffer.empty())
4906     Out.write((char *)&Buffer.front(), Buffer.size());
4907 }
4908 
4909 void IndexBitcodeWriter::write() {
4910   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4911 
4912   writeModuleVersion();
4913 
4914   // Write the module paths in the combined index.
4915   writeModStrings();
4916 
4917   // Write the summary combined index records.
4918   writeCombinedGlobalValueSummary();
4919 
4920   Stream.ExitBlock();
4921 }
4922 
4923 // Write the specified module summary index to the given raw output stream,
4924 // where it will be written in a new bitcode block. This is used when
4925 // writing the combined index file for ThinLTO. When writing a subset of the
4926 // index for a distributed backend, provide a \p ModuleToSummariesForIndex map.
4927 void llvm::writeIndexToFile(
4928     const ModuleSummaryIndex &Index, raw_ostream &Out,
4929     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4930   SmallVector<char, 0> Buffer;
4931   Buffer.reserve(256 * 1024);
4932 
4933   BitcodeWriter Writer(Buffer);
4934   Writer.writeIndex(&Index, ModuleToSummariesForIndex);
4935   Writer.writeStrtab();
4936 
4937   Out.write((char *)&Buffer.front(), Buffer.size());
4938 }
4939 
4940 namespace {
4941 
4942 /// Class to manage the bitcode writing for a thin link bitcode file.
4943 class ThinLinkBitcodeWriter : public ModuleBitcodeWriterBase {
4944   /// ModHash is for use in ThinLTO incremental build, generated while writing
4945   /// the module bitcode file.
4946   const ModuleHash *ModHash;
4947 
4948 public:
4949   ThinLinkBitcodeWriter(const Module &M, StringTableBuilder &StrtabBuilder,
4950                         BitstreamWriter &Stream,
4951                         const ModuleSummaryIndex &Index,
4952                         const ModuleHash &ModHash)
4953       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
4954                                 /*ShouldPreserveUseListOrder=*/false, &Index),
4955         ModHash(&ModHash) {}
4956 
4957   void write();
4958 
4959 private:
4960   void writeSimplifiedModuleInfo();
4961 };
4962 
4963 } // end anonymous namespace
4964 
4965 // This function writes a simpilified module info for thin link bitcode file.
4966 // It only contains the source file name along with the name(the offset and
4967 // size in strtab) and linkage for global values. For the global value info
4968 // entry, in order to keep linkage at offset 5, there are three zeros used
4969 // as padding.
4970 void ThinLinkBitcodeWriter::writeSimplifiedModuleInfo() {
4971   SmallVector<unsigned, 64> Vals;
4972   // Emit the module's source file name.
4973   {
4974     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
4975     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
4976     if (Bits == SE_Char6)
4977       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
4978     else if (Bits == SE_Fixed7)
4979       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
4980 
4981     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
4982     auto Abbv = std::make_shared<BitCodeAbbrev>();
4983     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
4984     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4985     Abbv->Add(AbbrevOpToUse);
4986     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4987 
4988     for (const auto P : M.getSourceFileName())
4989       Vals.push_back((unsigned char)P);
4990 
4991     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
4992     Vals.clear();
4993   }
4994 
4995   // Emit the global variable information.
4996   for (const GlobalVariable &GV : M.globals()) {
4997     // GLOBALVAR: [strtab offset, strtab size, 0, 0, 0, linkage]
4998     Vals.push_back(StrtabBuilder.add(GV.getName()));
4999     Vals.push_back(GV.getName().size());
5000     Vals.push_back(0);
5001     Vals.push_back(0);
5002     Vals.push_back(0);
5003     Vals.push_back(getEncodedLinkage(GV));
5004 
5005     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals);
5006     Vals.clear();
5007   }
5008 
5009   // Emit the function proto information.
5010   for (const Function &F : M) {
5011     // FUNCTION:  [strtab offset, strtab size, 0, 0, 0, linkage]
5012     Vals.push_back(StrtabBuilder.add(F.getName()));
5013     Vals.push_back(F.getName().size());
5014     Vals.push_back(0);
5015     Vals.push_back(0);
5016     Vals.push_back(0);
5017     Vals.push_back(getEncodedLinkage(F));
5018 
5019     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals);
5020     Vals.clear();
5021   }
5022 
5023   // Emit the alias information.
5024   for (const GlobalAlias &A : M.aliases()) {
5025     // ALIAS: [strtab offset, strtab size, 0, 0, 0, linkage]
5026     Vals.push_back(StrtabBuilder.add(A.getName()));
5027     Vals.push_back(A.getName().size());
5028     Vals.push_back(0);
5029     Vals.push_back(0);
5030     Vals.push_back(0);
5031     Vals.push_back(getEncodedLinkage(A));
5032 
5033     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals);
5034     Vals.clear();
5035   }
5036 
5037   // Emit the ifunc information.
5038   for (const GlobalIFunc &I : M.ifuncs()) {
5039     // IFUNC: [strtab offset, strtab size, 0, 0, 0, linkage]
5040     Vals.push_back(StrtabBuilder.add(I.getName()));
5041     Vals.push_back(I.getName().size());
5042     Vals.push_back(0);
5043     Vals.push_back(0);
5044     Vals.push_back(0);
5045     Vals.push_back(getEncodedLinkage(I));
5046 
5047     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
5048     Vals.clear();
5049   }
5050 }
5051 
5052 void ThinLinkBitcodeWriter::write() {
5053   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
5054 
5055   writeModuleVersion();
5056 
5057   writeSimplifiedModuleInfo();
5058 
5059   writePerModuleGlobalValueSummary();
5060 
5061   // Write module hash.
5062   Stream.EmitRecord(bitc::MODULE_CODE_HASH, ArrayRef<uint32_t>(*ModHash));
5063 
5064   Stream.ExitBlock();
5065 }
5066 
5067 void BitcodeWriter::writeThinLinkBitcode(const Module &M,
5068                                          const ModuleSummaryIndex &Index,
5069                                          const ModuleHash &ModHash) {
5070   assert(!WroteStrtab);
5071 
5072   // The Mods vector is used by irsymtab::build, which requires non-const
5073   // Modules in case it needs to materialize metadata. But the bitcode writer
5074   // requires that the module is materialized, so we can cast to non-const here,
5075   // after checking that it is in fact materialized.
5076   assert(M.isMaterialized());
5077   Mods.push_back(const_cast<Module *>(&M));
5078 
5079   ThinLinkBitcodeWriter ThinLinkWriter(M, StrtabBuilder, *Stream, Index,
5080                                        ModHash);
5081   ThinLinkWriter.write();
5082 }
5083 
5084 // Write the specified thin link bitcode file to the given raw output stream,
5085 // where it will be written in a new bitcode block. This is used when
5086 // writing the per-module index file for ThinLTO.
5087 void llvm::writeThinLinkBitcodeToFile(const Module &M, raw_ostream &Out,
5088                                       const ModuleSummaryIndex &Index,
5089                                       const ModuleHash &ModHash) {
5090   SmallVector<char, 0> Buffer;
5091   Buffer.reserve(256 * 1024);
5092 
5093   BitcodeWriter Writer(Buffer);
5094   Writer.writeThinLinkBitcode(M, Index, ModHash);
5095   Writer.writeSymtab();
5096   Writer.writeStrtab();
5097 
5098   Out.write((char *)&Buffer.front(), Buffer.size());
5099 }
5100 
5101 static const char *getSectionNameForBitcode(const Triple &T) {
5102   switch (T.getObjectFormat()) {
5103   case Triple::MachO:
5104     return "__LLVM,__bitcode";
5105   case Triple::COFF:
5106   case Triple::ELF:
5107   case Triple::Wasm:
5108   case Triple::UnknownObjectFormat:
5109     return ".llvmbc";
5110   case Triple::GOFF:
5111     llvm_unreachable("GOFF is not yet implemented");
5112     break;
5113   case Triple::SPIRV:
5114     llvm_unreachable("SPIRV is not yet implemented");
5115     break;
5116   case Triple::XCOFF:
5117     llvm_unreachable("XCOFF is not yet implemented");
5118     break;
5119   case Triple::DXContainer:
5120     llvm_unreachable("DXContainer is not yet implemented");
5121     break;
5122   }
5123   llvm_unreachable("Unimplemented ObjectFormatType");
5124 }
5125 
5126 static const char *getSectionNameForCommandline(const Triple &T) {
5127   switch (T.getObjectFormat()) {
5128   case Triple::MachO:
5129     return "__LLVM,__cmdline";
5130   case Triple::COFF:
5131   case Triple::ELF:
5132   case Triple::Wasm:
5133   case Triple::UnknownObjectFormat:
5134     return ".llvmcmd";
5135   case Triple::GOFF:
5136     llvm_unreachable("GOFF is not yet implemented");
5137     break;
5138   case Triple::SPIRV:
5139     llvm_unreachable("SPIRV is not yet implemented");
5140     break;
5141   case Triple::XCOFF:
5142     llvm_unreachable("XCOFF is not yet implemented");
5143     break;
5144   case Triple::DXContainer:
5145     llvm_unreachable("DXC is not yet implemented");
5146     break;
5147   }
5148   llvm_unreachable("Unimplemented ObjectFormatType");
5149 }
5150 
5151 void llvm::embedBitcodeInModule(llvm::Module &M, llvm::MemoryBufferRef Buf,
5152                                 bool EmbedBitcode, bool EmbedCmdline,
5153                                 const std::vector<uint8_t> &CmdArgs) {
5154   // Save llvm.compiler.used and remove it.
5155   SmallVector<Constant *, 2> UsedArray;
5156   SmallVector<GlobalValue *, 4> UsedGlobals;
5157   Type *UsedElementType = Type::getInt8Ty(M.getContext())->getPointerTo(0);
5158   GlobalVariable *Used = collectUsedGlobalVariables(M, UsedGlobals, true);
5159   for (auto *GV : UsedGlobals) {
5160     if (GV->getName() != "llvm.embedded.module" &&
5161         GV->getName() != "llvm.cmdline")
5162       UsedArray.push_back(
5163           ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
5164   }
5165   if (Used)
5166     Used->eraseFromParent();
5167 
5168   // Embed the bitcode for the llvm module.
5169   std::string Data;
5170   ArrayRef<uint8_t> ModuleData;
5171   Triple T(M.getTargetTriple());
5172 
5173   if (EmbedBitcode) {
5174     if (Buf.getBufferSize() == 0 ||
5175         !isBitcode((const unsigned char *)Buf.getBufferStart(),
5176                    (const unsigned char *)Buf.getBufferEnd())) {
5177       // If the input is LLVM Assembly, bitcode is produced by serializing
5178       // the module. Use-lists order need to be preserved in this case.
5179       llvm::raw_string_ostream OS(Data);
5180       llvm::WriteBitcodeToFile(M, OS, /* ShouldPreserveUseListOrder */ true);
5181       ModuleData =
5182           ArrayRef<uint8_t>((const uint8_t *)OS.str().data(), OS.str().size());
5183     } else
5184       // If the input is LLVM bitcode, write the input byte stream directly.
5185       ModuleData = ArrayRef<uint8_t>((const uint8_t *)Buf.getBufferStart(),
5186                                      Buf.getBufferSize());
5187   }
5188   llvm::Constant *ModuleConstant =
5189       llvm::ConstantDataArray::get(M.getContext(), ModuleData);
5190   llvm::GlobalVariable *GV = new llvm::GlobalVariable(
5191       M, ModuleConstant->getType(), true, llvm::GlobalValue::PrivateLinkage,
5192       ModuleConstant);
5193   GV->setSection(getSectionNameForBitcode(T));
5194   // Set alignment to 1 to prevent padding between two contributions from input
5195   // sections after linking.
5196   GV->setAlignment(Align(1));
5197   UsedArray.push_back(
5198       ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
5199   if (llvm::GlobalVariable *Old =
5200           M.getGlobalVariable("llvm.embedded.module", true)) {
5201     assert(Old->hasZeroLiveUses() &&
5202            "llvm.embedded.module can only be used once in llvm.compiler.used");
5203     GV->takeName(Old);
5204     Old->eraseFromParent();
5205   } else {
5206     GV->setName("llvm.embedded.module");
5207   }
5208 
5209   // Skip if only bitcode needs to be embedded.
5210   if (EmbedCmdline) {
5211     // Embed command-line options.
5212     ArrayRef<uint8_t> CmdData(const_cast<uint8_t *>(CmdArgs.data()),
5213                               CmdArgs.size());
5214     llvm::Constant *CmdConstant =
5215         llvm::ConstantDataArray::get(M.getContext(), CmdData);
5216     GV = new llvm::GlobalVariable(M, CmdConstant->getType(), true,
5217                                   llvm::GlobalValue::PrivateLinkage,
5218                                   CmdConstant);
5219     GV->setSection(getSectionNameForCommandline(T));
5220     GV->setAlignment(Align(1));
5221     UsedArray.push_back(
5222         ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
5223     if (llvm::GlobalVariable *Old = M.getGlobalVariable("llvm.cmdline", true)) {
5224       assert(Old->hasZeroLiveUses() &&
5225              "llvm.cmdline can only be used once in llvm.compiler.used");
5226       GV->takeName(Old);
5227       Old->eraseFromParent();
5228     } else {
5229       GV->setName("llvm.cmdline");
5230     }
5231   }
5232 
5233   if (UsedArray.empty())
5234     return;
5235 
5236   // Recreate llvm.compiler.used.
5237   ArrayType *ATy = ArrayType::get(UsedElementType, UsedArray.size());
5238   auto *NewUsed = new GlobalVariable(
5239       M, ATy, false, llvm::GlobalValue::AppendingLinkage,
5240       llvm::ConstantArray::get(ATy, UsedArray), "llvm.compiler.used");
5241   NewUsed->setSection("llvm.metadata");
5242 }
5243