xref: /llvm-project/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp (revision f7dffc28b3f82e25a0e283d2b11ffb9c6a129340)
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/ADT/Triple.h"
27 #include "llvm/Bitcode/BitcodeCommon.h"
28 #include "llvm/Bitcode/BitcodeReader.h"
29 #include "llvm/Bitcode/LLVMBitCodes.h"
30 #include "llvm/Bitstream/BitCodes.h"
31 #include "llvm/Bitstream/BitstreamWriter.h"
32 #include "llvm/Config/llvm-config.h"
33 #include "llvm/IR/Attributes.h"
34 #include "llvm/IR/BasicBlock.h"
35 #include "llvm/IR/Comdat.h"
36 #include "llvm/IR/Constant.h"
37 #include "llvm/IR/Constants.h"
38 #include "llvm/IR/DebugInfoMetadata.h"
39 #include "llvm/IR/DebugLoc.h"
40 #include "llvm/IR/DerivedTypes.h"
41 #include "llvm/IR/Function.h"
42 #include "llvm/IR/GlobalAlias.h"
43 #include "llvm/IR/GlobalIFunc.h"
44 #include "llvm/IR/GlobalObject.h"
45 #include "llvm/IR/GlobalValue.h"
46 #include "llvm/IR/GlobalVariable.h"
47 #include "llvm/IR/InlineAsm.h"
48 #include "llvm/IR/InstrTypes.h"
49 #include "llvm/IR/Instruction.h"
50 #include "llvm/IR/Instructions.h"
51 #include "llvm/IR/LLVMContext.h"
52 #include "llvm/IR/Metadata.h"
53 #include "llvm/IR/Module.h"
54 #include "llvm/IR/ModuleSummaryIndex.h"
55 #include "llvm/IR/Operator.h"
56 #include "llvm/IR/Type.h"
57 #include "llvm/IR/UseListOrder.h"
58 #include "llvm/IR/Value.h"
59 #include "llvm/IR/ValueSymbolTable.h"
60 #include "llvm/MC/StringTableBuilder.h"
61 #include "llvm/MC/TargetRegistry.h"
62 #include "llvm/Object/IRSymtab.h"
63 #include "llvm/Support/AtomicOrdering.h"
64 #include "llvm/Support/Casting.h"
65 #include "llvm/Support/CommandLine.h"
66 #include "llvm/Support/Endian.h"
67 #include "llvm/Support/Error.h"
68 #include "llvm/Support/ErrorHandling.h"
69 #include "llvm/Support/MathExtras.h"
70 #include "llvm/Support/SHA1.h"
71 #include "llvm/Support/raw_ostream.h"
72 #include <algorithm>
73 #include <cassert>
74 #include <cstddef>
75 #include <cstdint>
76 #include <iterator>
77 #include <map>
78 #include <memory>
79 #include <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   }
608 }
609 
610 static unsigned getEncodedOrdering(AtomicOrdering Ordering) {
611   switch (Ordering) {
612   case AtomicOrdering::NotAtomic: return bitc::ORDERING_NOTATOMIC;
613   case AtomicOrdering::Unordered: return bitc::ORDERING_UNORDERED;
614   case AtomicOrdering::Monotonic: return bitc::ORDERING_MONOTONIC;
615   case AtomicOrdering::Acquire: return bitc::ORDERING_ACQUIRE;
616   case AtomicOrdering::Release: return bitc::ORDERING_RELEASE;
617   case AtomicOrdering::AcquireRelease: return bitc::ORDERING_ACQREL;
618   case AtomicOrdering::SequentiallyConsistent: return bitc::ORDERING_SEQCST;
619   }
620   llvm_unreachable("Invalid ordering");
621 }
622 
623 static void writeStringRecord(BitstreamWriter &Stream, unsigned Code,
624                               StringRef Str, unsigned AbbrevToUse) {
625   SmallVector<unsigned, 64> Vals;
626 
627   // Code: [strchar x N]
628   for (char C : Str) {
629     if (AbbrevToUse && !BitCodeAbbrevOp::isChar6(C))
630       AbbrevToUse = 0;
631     Vals.push_back(C);
632   }
633 
634   // Emit the finished record.
635   Stream.EmitRecord(Code, Vals, AbbrevToUse);
636 }
637 
638 static uint64_t getAttrKindEncoding(Attribute::AttrKind Kind) {
639   switch (Kind) {
640   case Attribute::Alignment:
641     return bitc::ATTR_KIND_ALIGNMENT;
642   case Attribute::AllocAlign:
643     return bitc::ATTR_KIND_ALLOC_ALIGN;
644   case Attribute::AllocSize:
645     return bitc::ATTR_KIND_ALLOC_SIZE;
646   case Attribute::AlwaysInline:
647     return bitc::ATTR_KIND_ALWAYS_INLINE;
648   case Attribute::Builtin:
649     return bitc::ATTR_KIND_BUILTIN;
650   case Attribute::ByVal:
651     return bitc::ATTR_KIND_BY_VAL;
652   case Attribute::Convergent:
653     return bitc::ATTR_KIND_CONVERGENT;
654   case Attribute::InAlloca:
655     return bitc::ATTR_KIND_IN_ALLOCA;
656   case Attribute::Cold:
657     return bitc::ATTR_KIND_COLD;
658   case Attribute::DisableSanitizerInstrumentation:
659     return bitc::ATTR_KIND_DISABLE_SANITIZER_INSTRUMENTATION;
660   case Attribute::FnRetThunkExtern:
661     return bitc::ATTR_KIND_FNRETTHUNK_EXTERN;
662   case Attribute::Hot:
663     return bitc::ATTR_KIND_HOT;
664   case Attribute::ElementType:
665     return bitc::ATTR_KIND_ELEMENTTYPE;
666   case Attribute::InlineHint:
667     return bitc::ATTR_KIND_INLINE_HINT;
668   case Attribute::InReg:
669     return bitc::ATTR_KIND_IN_REG;
670   case Attribute::JumpTable:
671     return bitc::ATTR_KIND_JUMP_TABLE;
672   case Attribute::MinSize:
673     return bitc::ATTR_KIND_MIN_SIZE;
674   case Attribute::AllocatedPointer:
675     return bitc::ATTR_KIND_ALLOCATED_POINTER;
676   case Attribute::AllocKind:
677     return bitc::ATTR_KIND_ALLOC_KIND;
678   case Attribute::Memory:
679     return bitc::ATTR_KIND_MEMORY;
680   case Attribute::Naked:
681     return bitc::ATTR_KIND_NAKED;
682   case Attribute::Nest:
683     return bitc::ATTR_KIND_NEST;
684   case Attribute::NoAlias:
685     return bitc::ATTR_KIND_NO_ALIAS;
686   case Attribute::NoBuiltin:
687     return bitc::ATTR_KIND_NO_BUILTIN;
688   case Attribute::NoCallback:
689     return bitc::ATTR_KIND_NO_CALLBACK;
690   case Attribute::NoCapture:
691     return bitc::ATTR_KIND_NO_CAPTURE;
692   case Attribute::NoDuplicate:
693     return bitc::ATTR_KIND_NO_DUPLICATE;
694   case Attribute::NoFree:
695     return bitc::ATTR_KIND_NOFREE;
696   case Attribute::NoImplicitFloat:
697     return bitc::ATTR_KIND_NO_IMPLICIT_FLOAT;
698   case Attribute::NoInline:
699     return bitc::ATTR_KIND_NO_INLINE;
700   case Attribute::NoRecurse:
701     return bitc::ATTR_KIND_NO_RECURSE;
702   case Attribute::NoMerge:
703     return bitc::ATTR_KIND_NO_MERGE;
704   case Attribute::NonLazyBind:
705     return bitc::ATTR_KIND_NON_LAZY_BIND;
706   case Attribute::NonNull:
707     return bitc::ATTR_KIND_NON_NULL;
708   case Attribute::Dereferenceable:
709     return bitc::ATTR_KIND_DEREFERENCEABLE;
710   case Attribute::DereferenceableOrNull:
711     return bitc::ATTR_KIND_DEREFERENCEABLE_OR_NULL;
712   case Attribute::NoRedZone:
713     return bitc::ATTR_KIND_NO_RED_ZONE;
714   case Attribute::NoReturn:
715     return bitc::ATTR_KIND_NO_RETURN;
716   case Attribute::NoSync:
717     return bitc::ATTR_KIND_NOSYNC;
718   case Attribute::NoCfCheck:
719     return bitc::ATTR_KIND_NOCF_CHECK;
720   case Attribute::NoProfile:
721     return bitc::ATTR_KIND_NO_PROFILE;
722   case Attribute::SkipProfile:
723     return bitc::ATTR_KIND_SKIP_PROFILE;
724   case Attribute::NoUnwind:
725     return bitc::ATTR_KIND_NO_UNWIND;
726   case Attribute::NoSanitizeBounds:
727     return bitc::ATTR_KIND_NO_SANITIZE_BOUNDS;
728   case Attribute::NoSanitizeCoverage:
729     return bitc::ATTR_KIND_NO_SANITIZE_COVERAGE;
730   case Attribute::NullPointerIsValid:
731     return bitc::ATTR_KIND_NULL_POINTER_IS_VALID;
732   case Attribute::OptForFuzzing:
733     return bitc::ATTR_KIND_OPT_FOR_FUZZING;
734   case Attribute::OptimizeForSize:
735     return bitc::ATTR_KIND_OPTIMIZE_FOR_SIZE;
736   case Attribute::OptimizeNone:
737     return bitc::ATTR_KIND_OPTIMIZE_NONE;
738   case Attribute::ReadNone:
739     return bitc::ATTR_KIND_READ_NONE;
740   case Attribute::ReadOnly:
741     return bitc::ATTR_KIND_READ_ONLY;
742   case Attribute::Returned:
743     return bitc::ATTR_KIND_RETURNED;
744   case Attribute::ReturnsTwice:
745     return bitc::ATTR_KIND_RETURNS_TWICE;
746   case Attribute::SExt:
747     return bitc::ATTR_KIND_S_EXT;
748   case Attribute::Speculatable:
749     return bitc::ATTR_KIND_SPECULATABLE;
750   case Attribute::StackAlignment:
751     return bitc::ATTR_KIND_STACK_ALIGNMENT;
752   case Attribute::StackProtect:
753     return bitc::ATTR_KIND_STACK_PROTECT;
754   case Attribute::StackProtectReq:
755     return bitc::ATTR_KIND_STACK_PROTECT_REQ;
756   case Attribute::StackProtectStrong:
757     return bitc::ATTR_KIND_STACK_PROTECT_STRONG;
758   case Attribute::SafeStack:
759     return bitc::ATTR_KIND_SAFESTACK;
760   case Attribute::ShadowCallStack:
761     return bitc::ATTR_KIND_SHADOWCALLSTACK;
762   case Attribute::StrictFP:
763     return bitc::ATTR_KIND_STRICT_FP;
764   case Attribute::StructRet:
765     return bitc::ATTR_KIND_STRUCT_RET;
766   case Attribute::SanitizeAddress:
767     return bitc::ATTR_KIND_SANITIZE_ADDRESS;
768   case Attribute::SanitizeHWAddress:
769     return bitc::ATTR_KIND_SANITIZE_HWADDRESS;
770   case Attribute::SanitizeThread:
771     return bitc::ATTR_KIND_SANITIZE_THREAD;
772   case Attribute::SanitizeMemory:
773     return bitc::ATTR_KIND_SANITIZE_MEMORY;
774   case Attribute::SpeculativeLoadHardening:
775     return bitc::ATTR_KIND_SPECULATIVE_LOAD_HARDENING;
776   case Attribute::SwiftError:
777     return bitc::ATTR_KIND_SWIFT_ERROR;
778   case Attribute::SwiftSelf:
779     return bitc::ATTR_KIND_SWIFT_SELF;
780   case Attribute::SwiftAsync:
781     return bitc::ATTR_KIND_SWIFT_ASYNC;
782   case Attribute::UWTable:
783     return bitc::ATTR_KIND_UW_TABLE;
784   case Attribute::VScaleRange:
785     return bitc::ATTR_KIND_VSCALE_RANGE;
786   case Attribute::WillReturn:
787     return bitc::ATTR_KIND_WILLRETURN;
788   case Attribute::WriteOnly:
789     return bitc::ATTR_KIND_WRITEONLY;
790   case Attribute::ZExt:
791     return bitc::ATTR_KIND_Z_EXT;
792   case Attribute::ImmArg:
793     return bitc::ATTR_KIND_IMMARG;
794   case Attribute::SanitizeMemTag:
795     return bitc::ATTR_KIND_SANITIZE_MEMTAG;
796   case Attribute::Preallocated:
797     return bitc::ATTR_KIND_PREALLOCATED;
798   case Attribute::NoUndef:
799     return bitc::ATTR_KIND_NOUNDEF;
800   case Attribute::ByRef:
801     return bitc::ATTR_KIND_BYREF;
802   case Attribute::MustProgress:
803     return bitc::ATTR_KIND_MUSTPROGRESS;
804   case Attribute::PresplitCoroutine:
805     return bitc::ATTR_KIND_PRESPLIT_COROUTINE;
806   case Attribute::EndAttrKinds:
807     llvm_unreachable("Can not encode end-attribute kinds marker.");
808   case Attribute::None:
809     llvm_unreachable("Can not encode none-attribute.");
810   case Attribute::EmptyKey:
811   case Attribute::TombstoneKey:
812     llvm_unreachable("Trying to encode EmptyKey/TombstoneKey");
813   }
814 
815   llvm_unreachable("Trying to encode unknown attribute");
816 }
817 
818 void ModuleBitcodeWriter::writeAttributeGroupTable() {
819   const std::vector<ValueEnumerator::IndexAndAttrSet> &AttrGrps =
820       VE.getAttributeGroups();
821   if (AttrGrps.empty()) return;
822 
823   Stream.EnterSubblock(bitc::PARAMATTR_GROUP_BLOCK_ID, 3);
824 
825   SmallVector<uint64_t, 64> Record;
826   for (ValueEnumerator::IndexAndAttrSet Pair : AttrGrps) {
827     unsigned AttrListIndex = Pair.first;
828     AttributeSet AS = Pair.second;
829     Record.push_back(VE.getAttributeGroupID(Pair));
830     Record.push_back(AttrListIndex);
831 
832     for (Attribute Attr : AS) {
833       if (Attr.isEnumAttribute()) {
834         Record.push_back(0);
835         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
836       } else if (Attr.isIntAttribute()) {
837         Record.push_back(1);
838         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
839         Record.push_back(Attr.getValueAsInt());
840       } else if (Attr.isStringAttribute()) {
841         StringRef Kind = Attr.getKindAsString();
842         StringRef Val = Attr.getValueAsString();
843 
844         Record.push_back(Val.empty() ? 3 : 4);
845         Record.append(Kind.begin(), Kind.end());
846         Record.push_back(0);
847         if (!Val.empty()) {
848           Record.append(Val.begin(), Val.end());
849           Record.push_back(0);
850         }
851       } else {
852         assert(Attr.isTypeAttribute());
853         Type *Ty = Attr.getValueAsType();
854         Record.push_back(Ty ? 6 : 5);
855         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
856         if (Ty)
857           Record.push_back(VE.getTypeID(Attr.getValueAsType()));
858       }
859     }
860 
861     Stream.EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
862     Record.clear();
863   }
864 
865   Stream.ExitBlock();
866 }
867 
868 void ModuleBitcodeWriter::writeAttributeTable() {
869   const std::vector<AttributeList> &Attrs = VE.getAttributeLists();
870   if (Attrs.empty()) return;
871 
872   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
873 
874   SmallVector<uint64_t, 64> Record;
875   for (const AttributeList &AL : Attrs) {
876     for (unsigned i : AL.indexes()) {
877       AttributeSet AS = AL.getAttributes(i);
878       if (AS.hasAttributes())
879         Record.push_back(VE.getAttributeGroupID({i, AS}));
880     }
881 
882     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
883     Record.clear();
884   }
885 
886   Stream.ExitBlock();
887 }
888 
889 /// WriteTypeTable - Write out the type table for a module.
890 void ModuleBitcodeWriter::writeTypeTable() {
891   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
892 
893   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
894   SmallVector<uint64_t, 64> TypeVals;
895 
896   uint64_t NumBits = VE.computeBitsRequiredForTypeIndicies();
897 
898   // Abbrev for TYPE_CODE_POINTER.
899   auto Abbv = std::make_shared<BitCodeAbbrev>();
900   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
901   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
902   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
903   unsigned PtrAbbrev = Stream.EmitAbbrev(std::move(Abbv));
904 
905   // Abbrev for TYPE_CODE_OPAQUE_POINTER.
906   Abbv = std::make_shared<BitCodeAbbrev>();
907   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_OPAQUE_POINTER));
908   Abbv->Add(BitCodeAbbrevOp(0)); // Addrspace = 0
909   unsigned OpaquePtrAbbrev = Stream.EmitAbbrev(std::move(Abbv));
910 
911   // Abbrev for TYPE_CODE_FUNCTION.
912   Abbv = std::make_shared<BitCodeAbbrev>();
913   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
914   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
915   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
916   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
917   unsigned FunctionAbbrev = Stream.EmitAbbrev(std::move(Abbv));
918 
919   // Abbrev for TYPE_CODE_STRUCT_ANON.
920   Abbv = std::make_shared<BitCodeAbbrev>();
921   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
922   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
923   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
924   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
925   unsigned StructAnonAbbrev = Stream.EmitAbbrev(std::move(Abbv));
926 
927   // Abbrev for TYPE_CODE_STRUCT_NAME.
928   Abbv = std::make_shared<BitCodeAbbrev>();
929   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
930   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
931   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
932   unsigned StructNameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
933 
934   // Abbrev for TYPE_CODE_STRUCT_NAMED.
935   Abbv = std::make_shared<BitCodeAbbrev>();
936   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
937   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
938   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
939   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
940   unsigned StructNamedAbbrev = Stream.EmitAbbrev(std::move(Abbv));
941 
942   // Abbrev for TYPE_CODE_ARRAY.
943   Abbv = std::make_shared<BitCodeAbbrev>();
944   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
945   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
946   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
947   unsigned ArrayAbbrev = Stream.EmitAbbrev(std::move(Abbv));
948 
949   // Emit an entry count so the reader can reserve space.
950   TypeVals.push_back(TypeList.size());
951   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
952   TypeVals.clear();
953 
954   // Loop over all of the types, emitting each in turn.
955   for (Type *T : TypeList) {
956     int AbbrevToUse = 0;
957     unsigned Code = 0;
958 
959     switch (T->getTypeID()) {
960     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;      break;
961     case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;      break;
962     case Type::BFloatTyID:    Code = bitc::TYPE_CODE_BFLOAT;    break;
963     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;     break;
964     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE;    break;
965     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80;  break;
966     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128;     break;
967     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
968     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;     break;
969     case Type::MetadataTyID:  Code = bitc::TYPE_CODE_METADATA;  break;
970     case Type::X86_MMXTyID:   Code = bitc::TYPE_CODE_X86_MMX;   break;
971     case Type::X86_AMXTyID:   Code = bitc::TYPE_CODE_X86_AMX;   break;
972     case Type::TokenTyID:     Code = bitc::TYPE_CODE_TOKEN;     break;
973     case Type::IntegerTyID:
974       // INTEGER: [width]
975       Code = bitc::TYPE_CODE_INTEGER;
976       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
977       break;
978     case Type::PointerTyID: {
979       PointerType *PTy = cast<PointerType>(T);
980       unsigned AddressSpace = PTy->getAddressSpace();
981       if (PTy->isOpaque()) {
982         // OPAQUE_POINTER: [address space]
983         Code = bitc::TYPE_CODE_OPAQUE_POINTER;
984         TypeVals.push_back(AddressSpace);
985         if (AddressSpace == 0)
986           AbbrevToUse = OpaquePtrAbbrev;
987       } else {
988         // POINTER: [pointee type, address space]
989         Code = bitc::TYPE_CODE_POINTER;
990         TypeVals.push_back(VE.getTypeID(PTy->getNonOpaquePointerElementType()));
991         TypeVals.push_back(AddressSpace);
992         if (AddressSpace == 0)
993           AbbrevToUse = PtrAbbrev;
994       }
995       break;
996     }
997     case Type::FunctionTyID: {
998       FunctionType *FT = cast<FunctionType>(T);
999       // FUNCTION: [isvararg, retty, paramty x N]
1000       Code = bitc::TYPE_CODE_FUNCTION;
1001       TypeVals.push_back(FT->isVarArg());
1002       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
1003       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
1004         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
1005       AbbrevToUse = FunctionAbbrev;
1006       break;
1007     }
1008     case Type::StructTyID: {
1009       StructType *ST = cast<StructType>(T);
1010       // STRUCT: [ispacked, eltty x N]
1011       TypeVals.push_back(ST->isPacked());
1012       // Output all of the element types.
1013       for (Type *ET : ST->elements())
1014         TypeVals.push_back(VE.getTypeID(ET));
1015 
1016       if (ST->isLiteral()) {
1017         Code = bitc::TYPE_CODE_STRUCT_ANON;
1018         AbbrevToUse = StructAnonAbbrev;
1019       } else {
1020         if (ST->isOpaque()) {
1021           Code = bitc::TYPE_CODE_OPAQUE;
1022         } else {
1023           Code = bitc::TYPE_CODE_STRUCT_NAMED;
1024           AbbrevToUse = StructNamedAbbrev;
1025         }
1026 
1027         // Emit the name if it is present.
1028         if (!ST->getName().empty())
1029           writeStringRecord(Stream, bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
1030                             StructNameAbbrev);
1031       }
1032       break;
1033     }
1034     case Type::ArrayTyID: {
1035       ArrayType *AT = cast<ArrayType>(T);
1036       // ARRAY: [numelts, eltty]
1037       Code = bitc::TYPE_CODE_ARRAY;
1038       TypeVals.push_back(AT->getNumElements());
1039       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
1040       AbbrevToUse = ArrayAbbrev;
1041       break;
1042     }
1043     case Type::FixedVectorTyID:
1044     case Type::ScalableVectorTyID: {
1045       VectorType *VT = cast<VectorType>(T);
1046       // VECTOR [numelts, eltty] or
1047       //        [numelts, eltty, scalable]
1048       Code = bitc::TYPE_CODE_VECTOR;
1049       TypeVals.push_back(VT->getElementCount().getKnownMinValue());
1050       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
1051       if (isa<ScalableVectorType>(VT))
1052         TypeVals.push_back(true);
1053       break;
1054     }
1055     case Type::TypedPointerTyID:
1056       llvm_unreachable("Typed pointers cannot be added to IR modules");
1057     }
1058 
1059     // Emit the finished record.
1060     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
1061     TypeVals.clear();
1062   }
1063 
1064   Stream.ExitBlock();
1065 }
1066 
1067 static unsigned getEncodedLinkage(const GlobalValue::LinkageTypes Linkage) {
1068   switch (Linkage) {
1069   case GlobalValue::ExternalLinkage:
1070     return 0;
1071   case GlobalValue::WeakAnyLinkage:
1072     return 16;
1073   case GlobalValue::AppendingLinkage:
1074     return 2;
1075   case GlobalValue::InternalLinkage:
1076     return 3;
1077   case GlobalValue::LinkOnceAnyLinkage:
1078     return 18;
1079   case GlobalValue::ExternalWeakLinkage:
1080     return 7;
1081   case GlobalValue::CommonLinkage:
1082     return 8;
1083   case GlobalValue::PrivateLinkage:
1084     return 9;
1085   case GlobalValue::WeakODRLinkage:
1086     return 17;
1087   case GlobalValue::LinkOnceODRLinkage:
1088     return 19;
1089   case GlobalValue::AvailableExternallyLinkage:
1090     return 12;
1091   }
1092   llvm_unreachable("Invalid linkage");
1093 }
1094 
1095 static unsigned getEncodedLinkage(const GlobalValue &GV) {
1096   return getEncodedLinkage(GV.getLinkage());
1097 }
1098 
1099 static uint64_t getEncodedFFlags(FunctionSummary::FFlags Flags) {
1100   uint64_t RawFlags = 0;
1101   RawFlags |= Flags.ReadNone;
1102   RawFlags |= (Flags.ReadOnly << 1);
1103   RawFlags |= (Flags.NoRecurse << 2);
1104   RawFlags |= (Flags.ReturnDoesNotAlias << 3);
1105   RawFlags |= (Flags.NoInline << 4);
1106   RawFlags |= (Flags.AlwaysInline << 5);
1107   RawFlags |= (Flags.NoUnwind << 6);
1108   RawFlags |= (Flags.MayThrow << 7);
1109   RawFlags |= (Flags.HasUnknownCall << 8);
1110   RawFlags |= (Flags.MustBeUnreachable << 9);
1111   return RawFlags;
1112 }
1113 
1114 // Decode the flags for GlobalValue in the summary. See getDecodedGVSummaryFlags
1115 // in BitcodeReader.cpp.
1116 static uint64_t getEncodedGVSummaryFlags(GlobalValueSummary::GVFlags Flags) {
1117   uint64_t RawFlags = 0;
1118 
1119   RawFlags |= Flags.NotEligibleToImport; // bool
1120   RawFlags |= (Flags.Live << 1);
1121   RawFlags |= (Flags.DSOLocal << 2);
1122   RawFlags |= (Flags.CanAutoHide << 3);
1123 
1124   // Linkage don't need to be remapped at that time for the summary. Any future
1125   // change to the getEncodedLinkage() function will need to be taken into
1126   // account here as well.
1127   RawFlags = (RawFlags << 4) | Flags.Linkage; // 4 bits
1128 
1129   RawFlags |= (Flags.Visibility << 8); // 2 bits
1130 
1131   return RawFlags;
1132 }
1133 
1134 static uint64_t getEncodedGVarFlags(GlobalVarSummary::GVarFlags Flags) {
1135   uint64_t RawFlags = Flags.MaybeReadOnly | (Flags.MaybeWriteOnly << 1) |
1136                       (Flags.Constant << 2) | Flags.VCallVisibility << 3;
1137   return RawFlags;
1138 }
1139 
1140 static unsigned getEncodedVisibility(const GlobalValue &GV) {
1141   switch (GV.getVisibility()) {
1142   case GlobalValue::DefaultVisibility:   return 0;
1143   case GlobalValue::HiddenVisibility:    return 1;
1144   case GlobalValue::ProtectedVisibility: return 2;
1145   }
1146   llvm_unreachable("Invalid visibility");
1147 }
1148 
1149 static unsigned getEncodedDLLStorageClass(const GlobalValue &GV) {
1150   switch (GV.getDLLStorageClass()) {
1151   case GlobalValue::DefaultStorageClass:   return 0;
1152   case GlobalValue::DLLImportStorageClass: return 1;
1153   case GlobalValue::DLLExportStorageClass: return 2;
1154   }
1155   llvm_unreachable("Invalid DLL storage class");
1156 }
1157 
1158 static unsigned getEncodedThreadLocalMode(const GlobalValue &GV) {
1159   switch (GV.getThreadLocalMode()) {
1160     case GlobalVariable::NotThreadLocal:         return 0;
1161     case GlobalVariable::GeneralDynamicTLSModel: return 1;
1162     case GlobalVariable::LocalDynamicTLSModel:   return 2;
1163     case GlobalVariable::InitialExecTLSModel:    return 3;
1164     case GlobalVariable::LocalExecTLSModel:      return 4;
1165   }
1166   llvm_unreachable("Invalid TLS model");
1167 }
1168 
1169 static unsigned getEncodedComdatSelectionKind(const Comdat &C) {
1170   switch (C.getSelectionKind()) {
1171   case Comdat::Any:
1172     return bitc::COMDAT_SELECTION_KIND_ANY;
1173   case Comdat::ExactMatch:
1174     return bitc::COMDAT_SELECTION_KIND_EXACT_MATCH;
1175   case Comdat::Largest:
1176     return bitc::COMDAT_SELECTION_KIND_LARGEST;
1177   case Comdat::NoDeduplicate:
1178     return bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES;
1179   case Comdat::SameSize:
1180     return bitc::COMDAT_SELECTION_KIND_SAME_SIZE;
1181   }
1182   llvm_unreachable("Invalid selection kind");
1183 }
1184 
1185 static unsigned getEncodedUnnamedAddr(const GlobalValue &GV) {
1186   switch (GV.getUnnamedAddr()) {
1187   case GlobalValue::UnnamedAddr::None:   return 0;
1188   case GlobalValue::UnnamedAddr::Local:  return 2;
1189   case GlobalValue::UnnamedAddr::Global: return 1;
1190   }
1191   llvm_unreachable("Invalid unnamed_addr");
1192 }
1193 
1194 size_t ModuleBitcodeWriter::addToStrtab(StringRef Str) {
1195   if (GenerateHash)
1196     Hasher.update(Str);
1197   return StrtabBuilder.add(Str);
1198 }
1199 
1200 void ModuleBitcodeWriter::writeComdats() {
1201   SmallVector<unsigned, 64> Vals;
1202   for (const Comdat *C : VE.getComdats()) {
1203     // COMDAT: [strtab offset, strtab size, selection_kind]
1204     Vals.push_back(addToStrtab(C->getName()));
1205     Vals.push_back(C->getName().size());
1206     Vals.push_back(getEncodedComdatSelectionKind(*C));
1207     Stream.EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
1208     Vals.clear();
1209   }
1210 }
1211 
1212 /// Write a record that will eventually hold the word offset of the
1213 /// module-level VST. For now the offset is 0, which will be backpatched
1214 /// after the real VST is written. Saves the bit offset to backpatch.
1215 void ModuleBitcodeWriter::writeValueSymbolTableForwardDecl() {
1216   // Write a placeholder value in for the offset of the real VST,
1217   // which is written after the function blocks so that it can include
1218   // the offset of each function. The placeholder offset will be
1219   // updated when the real VST is written.
1220   auto Abbv = std::make_shared<BitCodeAbbrev>();
1221   Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_VSTOFFSET));
1222   // Blocks are 32-bit aligned, so we can use a 32-bit word offset to
1223   // hold the real VST offset. Must use fixed instead of VBR as we don't
1224   // know how many VBR chunks to reserve ahead of time.
1225   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
1226   unsigned VSTOffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1227 
1228   // Emit the placeholder
1229   uint64_t Vals[] = {bitc::MODULE_CODE_VSTOFFSET, 0};
1230   Stream.EmitRecordWithAbbrev(VSTOffsetAbbrev, Vals);
1231 
1232   // Compute and save the bit offset to the placeholder, which will be
1233   // patched when the real VST is written. We can simply subtract the 32-bit
1234   // fixed size from the current bit number to get the location to backpatch.
1235   VSTOffsetPlaceholder = Stream.GetCurrentBitNo() - 32;
1236 }
1237 
1238 enum StringEncoding { SE_Char6, SE_Fixed7, SE_Fixed8 };
1239 
1240 /// Determine the encoding to use for the given string name and length.
1241 static StringEncoding getStringEncoding(StringRef Str) {
1242   bool isChar6 = true;
1243   for (char C : Str) {
1244     if (isChar6)
1245       isChar6 = BitCodeAbbrevOp::isChar6(C);
1246     if ((unsigned char)C & 128)
1247       // don't bother scanning the rest.
1248       return SE_Fixed8;
1249   }
1250   if (isChar6)
1251     return SE_Char6;
1252   return SE_Fixed7;
1253 }
1254 
1255 static_assert(sizeof(GlobalValue::SanitizerMetadata) <= sizeof(unsigned),
1256               "Sanitizer Metadata is too large for naive serialization.");
1257 static unsigned
1258 serializeSanitizerMetadata(const GlobalValue::SanitizerMetadata &Meta) {
1259   return Meta.NoAddress | (Meta.NoHWAddress << 1) |
1260          (Meta.Memtag << 2) | (Meta.IsDynInit << 3);
1261 }
1262 
1263 /// Emit top-level description of module, including target triple, inline asm,
1264 /// descriptors for global variables, and function prototype info.
1265 /// Returns the bit offset to backpatch with the location of the real VST.
1266 void ModuleBitcodeWriter::writeModuleInfo() {
1267   // Emit various pieces of data attached to a module.
1268   if (!M.getTargetTriple().empty())
1269     writeStringRecord(Stream, bitc::MODULE_CODE_TRIPLE, M.getTargetTriple(),
1270                       0 /*TODO*/);
1271   const std::string &DL = M.getDataLayoutStr();
1272   if (!DL.empty())
1273     writeStringRecord(Stream, bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/);
1274   if (!M.getModuleInlineAsm().empty())
1275     writeStringRecord(Stream, bitc::MODULE_CODE_ASM, M.getModuleInlineAsm(),
1276                       0 /*TODO*/);
1277 
1278   // Emit information about sections and GC, computing how many there are. Also
1279   // compute the maximum alignment value.
1280   std::map<std::string, unsigned> SectionMap;
1281   std::map<std::string, unsigned> GCMap;
1282   MaybeAlign MaxAlignment;
1283   unsigned MaxGlobalType = 0;
1284   const auto UpdateMaxAlignment = [&MaxAlignment](const MaybeAlign A) {
1285     if (A)
1286       MaxAlignment = !MaxAlignment ? *A : std::max(*MaxAlignment, *A);
1287   };
1288   for (const GlobalVariable &GV : M.globals()) {
1289     UpdateMaxAlignment(GV.getAlign());
1290     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getValueType()));
1291     if (GV.hasSection()) {
1292       // Give section names unique ID's.
1293       unsigned &Entry = SectionMap[std::string(GV.getSection())];
1294       if (!Entry) {
1295         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
1296                           0 /*TODO*/);
1297         Entry = SectionMap.size();
1298       }
1299     }
1300   }
1301   for (const Function &F : M) {
1302     UpdateMaxAlignment(F.getAlign());
1303     if (F.hasSection()) {
1304       // Give section names unique ID's.
1305       unsigned &Entry = SectionMap[std::string(F.getSection())];
1306       if (!Entry) {
1307         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
1308                           0 /*TODO*/);
1309         Entry = SectionMap.size();
1310       }
1311     }
1312     if (F.hasGC()) {
1313       // Same for GC names.
1314       unsigned &Entry = GCMap[F.getGC()];
1315       if (!Entry) {
1316         writeStringRecord(Stream, bitc::MODULE_CODE_GCNAME, F.getGC(),
1317                           0 /*TODO*/);
1318         Entry = GCMap.size();
1319       }
1320     }
1321   }
1322 
1323   // Emit abbrev for globals, now that we know # sections and max alignment.
1324   unsigned SimpleGVarAbbrev = 0;
1325   if (!M.global_empty()) {
1326     // Add an abbrev for common globals with no visibility or thread localness.
1327     auto Abbv = std::make_shared<BitCodeAbbrev>();
1328     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
1329     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1330     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1331     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1332                               Log2_32_Ceil(MaxGlobalType+1)));
1333     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddrSpace << 2
1334                                                            //| explicitType << 1
1335                                                            //| constant
1336     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Initializer.
1337     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // Linkage.
1338     if (!MaxAlignment)                                     // Alignment.
1339       Abbv->Add(BitCodeAbbrevOp(0));
1340     else {
1341       unsigned MaxEncAlignment = getEncodedAlign(MaxAlignment);
1342       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1343                                Log2_32_Ceil(MaxEncAlignment+1)));
1344     }
1345     if (SectionMap.empty())                                    // Section.
1346       Abbv->Add(BitCodeAbbrevOp(0));
1347     else
1348       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1349                                Log2_32_Ceil(SectionMap.size()+1)));
1350     // Don't bother emitting vis + thread local.
1351     SimpleGVarAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1352   }
1353 
1354   SmallVector<unsigned, 64> Vals;
1355   // Emit the module's source file name.
1356   {
1357     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
1358     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
1359     if (Bits == SE_Char6)
1360       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
1361     else if (Bits == SE_Fixed7)
1362       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
1363 
1364     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
1365     auto Abbv = std::make_shared<BitCodeAbbrev>();
1366     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
1367     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1368     Abbv->Add(AbbrevOpToUse);
1369     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1370 
1371     for (const auto P : M.getSourceFileName())
1372       Vals.push_back((unsigned char)P);
1373 
1374     // Emit the finished record.
1375     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
1376     Vals.clear();
1377   }
1378 
1379   // Emit the global variable information.
1380   for (const GlobalVariable &GV : M.globals()) {
1381     unsigned AbbrevToUse = 0;
1382 
1383     // GLOBALVAR: [strtab offset, strtab size, type, isconst, initid,
1384     //             linkage, alignment, section, visibility, threadlocal,
1385     //             unnamed_addr, externally_initialized, dllstorageclass,
1386     //             comdat, attributes, DSO_Local, GlobalSanitizer]
1387     Vals.push_back(addToStrtab(GV.getName()));
1388     Vals.push_back(GV.getName().size());
1389     Vals.push_back(VE.getTypeID(GV.getValueType()));
1390     Vals.push_back(GV.getType()->getAddressSpace() << 2 | 2 | GV.isConstant());
1391     Vals.push_back(GV.isDeclaration() ? 0 :
1392                    (VE.getValueID(GV.getInitializer()) + 1));
1393     Vals.push_back(getEncodedLinkage(GV));
1394     Vals.push_back(getEncodedAlign(GV.getAlign()));
1395     Vals.push_back(GV.hasSection() ? SectionMap[std::string(GV.getSection())]
1396                                    : 0);
1397     if (GV.isThreadLocal() ||
1398         GV.getVisibility() != GlobalValue::DefaultVisibility ||
1399         GV.getUnnamedAddr() != GlobalValue::UnnamedAddr::None ||
1400         GV.isExternallyInitialized() ||
1401         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
1402         GV.hasComdat() || GV.hasAttributes() || GV.isDSOLocal() ||
1403         GV.hasPartition() || GV.hasSanitizerMetadata()) {
1404       Vals.push_back(getEncodedVisibility(GV));
1405       Vals.push_back(getEncodedThreadLocalMode(GV));
1406       Vals.push_back(getEncodedUnnamedAddr(GV));
1407       Vals.push_back(GV.isExternallyInitialized());
1408       Vals.push_back(getEncodedDLLStorageClass(GV));
1409       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
1410 
1411       auto AL = GV.getAttributesAsList(AttributeList::FunctionIndex);
1412       Vals.push_back(VE.getAttributeListID(AL));
1413 
1414       Vals.push_back(GV.isDSOLocal());
1415       Vals.push_back(addToStrtab(GV.getPartition()));
1416       Vals.push_back(GV.getPartition().size());
1417 
1418       Vals.push_back((GV.hasSanitizerMetadata() ? serializeSanitizerMetadata(
1419                                                       GV.getSanitizerMetadata())
1420                                                 : 0));
1421     } else {
1422       AbbrevToUse = SimpleGVarAbbrev;
1423     }
1424 
1425     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
1426     Vals.clear();
1427   }
1428 
1429   // Emit the function proto information.
1430   for (const Function &F : M) {
1431     // FUNCTION:  [strtab offset, strtab size, type, callingconv, isproto,
1432     //             linkage, paramattrs, alignment, section, visibility, gc,
1433     //             unnamed_addr, prologuedata, dllstorageclass, comdat,
1434     //             prefixdata, personalityfn, DSO_Local, addrspace]
1435     Vals.push_back(addToStrtab(F.getName()));
1436     Vals.push_back(F.getName().size());
1437     Vals.push_back(VE.getTypeID(F.getFunctionType()));
1438     Vals.push_back(F.getCallingConv());
1439     Vals.push_back(F.isDeclaration());
1440     Vals.push_back(getEncodedLinkage(F));
1441     Vals.push_back(VE.getAttributeListID(F.getAttributes()));
1442     Vals.push_back(getEncodedAlign(F.getAlign()));
1443     Vals.push_back(F.hasSection() ? SectionMap[std::string(F.getSection())]
1444                                   : 0);
1445     Vals.push_back(getEncodedVisibility(F));
1446     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
1447     Vals.push_back(getEncodedUnnamedAddr(F));
1448     Vals.push_back(F.hasPrologueData() ? (VE.getValueID(F.getPrologueData()) + 1)
1449                                        : 0);
1450     Vals.push_back(getEncodedDLLStorageClass(F));
1451     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
1452     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
1453                                      : 0);
1454     Vals.push_back(
1455         F.hasPersonalityFn() ? (VE.getValueID(F.getPersonalityFn()) + 1) : 0);
1456 
1457     Vals.push_back(F.isDSOLocal());
1458     Vals.push_back(F.getAddressSpace());
1459     Vals.push_back(addToStrtab(F.getPartition()));
1460     Vals.push_back(F.getPartition().size());
1461 
1462     unsigned AbbrevToUse = 0;
1463     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
1464     Vals.clear();
1465   }
1466 
1467   // Emit the alias information.
1468   for (const GlobalAlias &A : M.aliases()) {
1469     // ALIAS: [strtab offset, strtab size, alias type, aliasee val#, linkage,
1470     //         visibility, dllstorageclass, threadlocal, unnamed_addr,
1471     //         DSO_Local]
1472     Vals.push_back(addToStrtab(A.getName()));
1473     Vals.push_back(A.getName().size());
1474     Vals.push_back(VE.getTypeID(A.getValueType()));
1475     Vals.push_back(A.getType()->getAddressSpace());
1476     Vals.push_back(VE.getValueID(A.getAliasee()));
1477     Vals.push_back(getEncodedLinkage(A));
1478     Vals.push_back(getEncodedVisibility(A));
1479     Vals.push_back(getEncodedDLLStorageClass(A));
1480     Vals.push_back(getEncodedThreadLocalMode(A));
1481     Vals.push_back(getEncodedUnnamedAddr(A));
1482     Vals.push_back(A.isDSOLocal());
1483     Vals.push_back(addToStrtab(A.getPartition()));
1484     Vals.push_back(A.getPartition().size());
1485 
1486     unsigned AbbrevToUse = 0;
1487     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
1488     Vals.clear();
1489   }
1490 
1491   // Emit the ifunc information.
1492   for (const GlobalIFunc &I : M.ifuncs()) {
1493     // IFUNC: [strtab offset, strtab size, ifunc type, address space, resolver
1494     //         val#, linkage, visibility, DSO_Local]
1495     Vals.push_back(addToStrtab(I.getName()));
1496     Vals.push_back(I.getName().size());
1497     Vals.push_back(VE.getTypeID(I.getValueType()));
1498     Vals.push_back(I.getType()->getAddressSpace());
1499     Vals.push_back(VE.getValueID(I.getResolver()));
1500     Vals.push_back(getEncodedLinkage(I));
1501     Vals.push_back(getEncodedVisibility(I));
1502     Vals.push_back(I.isDSOLocal());
1503     Vals.push_back(addToStrtab(I.getPartition()));
1504     Vals.push_back(I.getPartition().size());
1505     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
1506     Vals.clear();
1507   }
1508 
1509   writeValueSymbolTableForwardDecl();
1510 }
1511 
1512 static uint64_t getOptimizationFlags(const Value *V) {
1513   uint64_t Flags = 0;
1514 
1515   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
1516     if (OBO->hasNoSignedWrap())
1517       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
1518     if (OBO->hasNoUnsignedWrap())
1519       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
1520   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
1521     if (PEO->isExact())
1522       Flags |= 1 << bitc::PEO_EXACT;
1523   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
1524     if (FPMO->hasAllowReassoc())
1525       Flags |= bitc::AllowReassoc;
1526     if (FPMO->hasNoNaNs())
1527       Flags |= bitc::NoNaNs;
1528     if (FPMO->hasNoInfs())
1529       Flags |= bitc::NoInfs;
1530     if (FPMO->hasNoSignedZeros())
1531       Flags |= bitc::NoSignedZeros;
1532     if (FPMO->hasAllowReciprocal())
1533       Flags |= bitc::AllowReciprocal;
1534     if (FPMO->hasAllowContract())
1535       Flags |= bitc::AllowContract;
1536     if (FPMO->hasApproxFunc())
1537       Flags |= bitc::ApproxFunc;
1538   }
1539 
1540   return Flags;
1541 }
1542 
1543 void ModuleBitcodeWriter::writeValueAsMetadata(
1544     const ValueAsMetadata *MD, SmallVectorImpl<uint64_t> &Record) {
1545   // Mimic an MDNode with a value as one operand.
1546   Value *V = MD->getValue();
1547   Record.push_back(VE.getTypeID(V->getType()));
1548   Record.push_back(VE.getValueID(V));
1549   Stream.EmitRecord(bitc::METADATA_VALUE, Record, 0);
1550   Record.clear();
1551 }
1552 
1553 void ModuleBitcodeWriter::writeMDTuple(const MDTuple *N,
1554                                        SmallVectorImpl<uint64_t> &Record,
1555                                        unsigned Abbrev) {
1556   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
1557     Metadata *MD = N->getOperand(i);
1558     assert(!(MD && isa<LocalAsMetadata>(MD)) &&
1559            "Unexpected function-local metadata");
1560     Record.push_back(VE.getMetadataOrNullID(MD));
1561   }
1562   Stream.EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
1563                                     : bitc::METADATA_NODE,
1564                     Record, Abbrev);
1565   Record.clear();
1566 }
1567 
1568 unsigned ModuleBitcodeWriter::createDILocationAbbrev() {
1569   // Assume the column is usually under 128, and always output the inlined-at
1570   // location (it's never more expensive than building an array size 1).
1571   auto Abbv = std::make_shared<BitCodeAbbrev>();
1572   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
1573   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1574   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1575   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1576   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1577   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1578   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1579   return Stream.EmitAbbrev(std::move(Abbv));
1580 }
1581 
1582 void ModuleBitcodeWriter::writeDILocation(const DILocation *N,
1583                                           SmallVectorImpl<uint64_t> &Record,
1584                                           unsigned &Abbrev) {
1585   if (!Abbrev)
1586     Abbrev = createDILocationAbbrev();
1587 
1588   Record.push_back(N->isDistinct());
1589   Record.push_back(N->getLine());
1590   Record.push_back(N->getColumn());
1591   Record.push_back(VE.getMetadataID(N->getScope()));
1592   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
1593   Record.push_back(N->isImplicitCode());
1594 
1595   Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
1596   Record.clear();
1597 }
1598 
1599 unsigned ModuleBitcodeWriter::createGenericDINodeAbbrev() {
1600   // Assume the column is usually under 128, and always output the inlined-at
1601   // location (it's never more expensive than building an array size 1).
1602   auto Abbv = std::make_shared<BitCodeAbbrev>();
1603   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
1604   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1605   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1606   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1607   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1608   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1609   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1610   return Stream.EmitAbbrev(std::move(Abbv));
1611 }
1612 
1613 void ModuleBitcodeWriter::writeGenericDINode(const GenericDINode *N,
1614                                              SmallVectorImpl<uint64_t> &Record,
1615                                              unsigned &Abbrev) {
1616   if (!Abbrev)
1617     Abbrev = createGenericDINodeAbbrev();
1618 
1619   Record.push_back(N->isDistinct());
1620   Record.push_back(N->getTag());
1621   Record.push_back(0); // Per-tag version field; unused for now.
1622 
1623   for (auto &I : N->operands())
1624     Record.push_back(VE.getMetadataOrNullID(I));
1625 
1626   Stream.EmitRecord(bitc::METADATA_GENERIC_DEBUG, Record, Abbrev);
1627   Record.clear();
1628 }
1629 
1630 void ModuleBitcodeWriter::writeDISubrange(const DISubrange *N,
1631                                           SmallVectorImpl<uint64_t> &Record,
1632                                           unsigned Abbrev) {
1633   const uint64_t Version = 2 << 1;
1634   Record.push_back((uint64_t)N->isDistinct() | Version);
1635   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1636   Record.push_back(VE.getMetadataOrNullID(N->getRawLowerBound()));
1637   Record.push_back(VE.getMetadataOrNullID(N->getRawUpperBound()));
1638   Record.push_back(VE.getMetadataOrNullID(N->getRawStride()));
1639 
1640   Stream.EmitRecord(bitc::METADATA_SUBRANGE, Record, Abbrev);
1641   Record.clear();
1642 }
1643 
1644 void ModuleBitcodeWriter::writeDIGenericSubrange(
1645     const DIGenericSubrange *N, SmallVectorImpl<uint64_t> &Record,
1646     unsigned Abbrev) {
1647   Record.push_back((uint64_t)N->isDistinct());
1648   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1649   Record.push_back(VE.getMetadataOrNullID(N->getRawLowerBound()));
1650   Record.push_back(VE.getMetadataOrNullID(N->getRawUpperBound()));
1651   Record.push_back(VE.getMetadataOrNullID(N->getRawStride()));
1652 
1653   Stream.EmitRecord(bitc::METADATA_GENERIC_SUBRANGE, Record, Abbrev);
1654   Record.clear();
1655 }
1656 
1657 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
1658   if ((int64_t)V >= 0)
1659     Vals.push_back(V << 1);
1660   else
1661     Vals.push_back((-V << 1) | 1);
1662 }
1663 
1664 static void emitWideAPInt(SmallVectorImpl<uint64_t> &Vals, const APInt &A) {
1665   // We have an arbitrary precision integer value to write whose
1666   // bit width is > 64. However, in canonical unsigned integer
1667   // format it is likely that the high bits are going to be zero.
1668   // So, we only write the number of active words.
1669   unsigned NumWords = A.getActiveWords();
1670   const uint64_t *RawData = A.getRawData();
1671   for (unsigned i = 0; i < NumWords; i++)
1672     emitSignedInt64(Vals, RawData[i]);
1673 }
1674 
1675 void ModuleBitcodeWriter::writeDIEnumerator(const DIEnumerator *N,
1676                                             SmallVectorImpl<uint64_t> &Record,
1677                                             unsigned Abbrev) {
1678   const uint64_t IsBigInt = 1 << 2;
1679   Record.push_back(IsBigInt | (N->isUnsigned() << 1) | N->isDistinct());
1680   Record.push_back(N->getValue().getBitWidth());
1681   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1682   emitWideAPInt(Record, N->getValue());
1683 
1684   Stream.EmitRecord(bitc::METADATA_ENUMERATOR, Record, Abbrev);
1685   Record.clear();
1686 }
1687 
1688 void ModuleBitcodeWriter::writeDIBasicType(const DIBasicType *N,
1689                                            SmallVectorImpl<uint64_t> &Record,
1690                                            unsigned Abbrev) {
1691   Record.push_back(N->isDistinct());
1692   Record.push_back(N->getTag());
1693   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1694   Record.push_back(N->getSizeInBits());
1695   Record.push_back(N->getAlignInBits());
1696   Record.push_back(N->getEncoding());
1697   Record.push_back(N->getFlags());
1698 
1699   Stream.EmitRecord(bitc::METADATA_BASIC_TYPE, Record, Abbrev);
1700   Record.clear();
1701 }
1702 
1703 void ModuleBitcodeWriter::writeDIStringType(const DIStringType *N,
1704                                             SmallVectorImpl<uint64_t> &Record,
1705                                             unsigned Abbrev) {
1706   Record.push_back(N->isDistinct());
1707   Record.push_back(N->getTag());
1708   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1709   Record.push_back(VE.getMetadataOrNullID(N->getStringLength()));
1710   Record.push_back(VE.getMetadataOrNullID(N->getStringLengthExp()));
1711   Record.push_back(VE.getMetadataOrNullID(N->getStringLocationExp()));
1712   Record.push_back(N->getSizeInBits());
1713   Record.push_back(N->getAlignInBits());
1714   Record.push_back(N->getEncoding());
1715 
1716   Stream.EmitRecord(bitc::METADATA_STRING_TYPE, Record, Abbrev);
1717   Record.clear();
1718 }
1719 
1720 void ModuleBitcodeWriter::writeDIDerivedType(const DIDerivedType *N,
1721                                              SmallVectorImpl<uint64_t> &Record,
1722                                              unsigned Abbrev) {
1723   Record.push_back(N->isDistinct());
1724   Record.push_back(N->getTag());
1725   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1726   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1727   Record.push_back(N->getLine());
1728   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1729   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1730   Record.push_back(N->getSizeInBits());
1731   Record.push_back(N->getAlignInBits());
1732   Record.push_back(N->getOffsetInBits());
1733   Record.push_back(N->getFlags());
1734   Record.push_back(VE.getMetadataOrNullID(N->getExtraData()));
1735 
1736   // DWARF address space is encoded as N->getDWARFAddressSpace() + 1. 0 means
1737   // that there is no DWARF address space associated with DIDerivedType.
1738   if (const auto &DWARFAddressSpace = N->getDWARFAddressSpace())
1739     Record.push_back(*DWARFAddressSpace + 1);
1740   else
1741     Record.push_back(0);
1742 
1743   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1744 
1745   Stream.EmitRecord(bitc::METADATA_DERIVED_TYPE, Record, Abbrev);
1746   Record.clear();
1747 }
1748 
1749 void ModuleBitcodeWriter::writeDICompositeType(
1750     const DICompositeType *N, SmallVectorImpl<uint64_t> &Record,
1751     unsigned Abbrev) {
1752   const unsigned IsNotUsedInOldTypeRef = 0x2;
1753   Record.push_back(IsNotUsedInOldTypeRef | (unsigned)N->isDistinct());
1754   Record.push_back(N->getTag());
1755   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1756   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1757   Record.push_back(N->getLine());
1758   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1759   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1760   Record.push_back(N->getSizeInBits());
1761   Record.push_back(N->getAlignInBits());
1762   Record.push_back(N->getOffsetInBits());
1763   Record.push_back(N->getFlags());
1764   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1765   Record.push_back(N->getRuntimeLang());
1766   Record.push_back(VE.getMetadataOrNullID(N->getVTableHolder()));
1767   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1768   Record.push_back(VE.getMetadataOrNullID(N->getRawIdentifier()));
1769   Record.push_back(VE.getMetadataOrNullID(N->getDiscriminator()));
1770   Record.push_back(VE.getMetadataOrNullID(N->getRawDataLocation()));
1771   Record.push_back(VE.getMetadataOrNullID(N->getRawAssociated()));
1772   Record.push_back(VE.getMetadataOrNullID(N->getRawAllocated()));
1773   Record.push_back(VE.getMetadataOrNullID(N->getRawRank()));
1774   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1775 
1776   Stream.EmitRecord(bitc::METADATA_COMPOSITE_TYPE, Record, Abbrev);
1777   Record.clear();
1778 }
1779 
1780 void ModuleBitcodeWriter::writeDISubroutineType(
1781     const DISubroutineType *N, SmallVectorImpl<uint64_t> &Record,
1782     unsigned Abbrev) {
1783   const unsigned HasNoOldTypeRefs = 0x2;
1784   Record.push_back(HasNoOldTypeRefs | (unsigned)N->isDistinct());
1785   Record.push_back(N->getFlags());
1786   Record.push_back(VE.getMetadataOrNullID(N->getTypeArray().get()));
1787   Record.push_back(N->getCC());
1788 
1789   Stream.EmitRecord(bitc::METADATA_SUBROUTINE_TYPE, Record, Abbrev);
1790   Record.clear();
1791 }
1792 
1793 void ModuleBitcodeWriter::writeDIFile(const DIFile *N,
1794                                       SmallVectorImpl<uint64_t> &Record,
1795                                       unsigned Abbrev) {
1796   Record.push_back(N->isDistinct());
1797   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
1798   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
1799   if (N->getRawChecksum()) {
1800     Record.push_back(N->getRawChecksum()->Kind);
1801     Record.push_back(VE.getMetadataOrNullID(N->getRawChecksum()->Value));
1802   } else {
1803     // Maintain backwards compatibility with the old internal representation of
1804     // CSK_None in ChecksumKind by writing nulls here when Checksum is None.
1805     Record.push_back(0);
1806     Record.push_back(VE.getMetadataOrNullID(nullptr));
1807   }
1808   auto Source = N->getRawSource();
1809   if (Source)
1810     Record.push_back(VE.getMetadataOrNullID(Source));
1811 
1812   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
1813   Record.clear();
1814 }
1815 
1816 void ModuleBitcodeWriter::writeDICompileUnit(const DICompileUnit *N,
1817                                              SmallVectorImpl<uint64_t> &Record,
1818                                              unsigned Abbrev) {
1819   assert(N->isDistinct() && "Expected distinct compile units");
1820   Record.push_back(/* IsDistinct */ true);
1821   Record.push_back(N->getSourceLanguage());
1822   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1823   Record.push_back(VE.getMetadataOrNullID(N->getRawProducer()));
1824   Record.push_back(N->isOptimized());
1825   Record.push_back(VE.getMetadataOrNullID(N->getRawFlags()));
1826   Record.push_back(N->getRuntimeVersion());
1827   Record.push_back(VE.getMetadataOrNullID(N->getRawSplitDebugFilename()));
1828   Record.push_back(N->getEmissionKind());
1829   Record.push_back(VE.getMetadataOrNullID(N->getEnumTypes().get()));
1830   Record.push_back(VE.getMetadataOrNullID(N->getRetainedTypes().get()));
1831   Record.push_back(/* subprograms */ 0);
1832   Record.push_back(VE.getMetadataOrNullID(N->getGlobalVariables().get()));
1833   Record.push_back(VE.getMetadataOrNullID(N->getImportedEntities().get()));
1834   Record.push_back(N->getDWOId());
1835   Record.push_back(VE.getMetadataOrNullID(N->getMacros().get()));
1836   Record.push_back(N->getSplitDebugInlining());
1837   Record.push_back(N->getDebugInfoForProfiling());
1838   Record.push_back((unsigned)N->getNameTableKind());
1839   Record.push_back(N->getRangesBaseAddress());
1840   Record.push_back(VE.getMetadataOrNullID(N->getRawSysRoot()));
1841   Record.push_back(VE.getMetadataOrNullID(N->getRawSDK()));
1842 
1843   Stream.EmitRecord(bitc::METADATA_COMPILE_UNIT, Record, Abbrev);
1844   Record.clear();
1845 }
1846 
1847 void ModuleBitcodeWriter::writeDISubprogram(const DISubprogram *N,
1848                                             SmallVectorImpl<uint64_t> &Record,
1849                                             unsigned Abbrev) {
1850   const uint64_t HasUnitFlag = 1 << 1;
1851   const uint64_t HasSPFlagsFlag = 1 << 2;
1852   Record.push_back(uint64_t(N->isDistinct()) | HasUnitFlag | HasSPFlagsFlag);
1853   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1854   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1855   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1856   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1857   Record.push_back(N->getLine());
1858   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1859   Record.push_back(N->getScopeLine());
1860   Record.push_back(VE.getMetadataOrNullID(N->getContainingType()));
1861   Record.push_back(N->getSPFlags());
1862   Record.push_back(N->getVirtualIndex());
1863   Record.push_back(N->getFlags());
1864   Record.push_back(VE.getMetadataOrNullID(N->getRawUnit()));
1865   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1866   Record.push_back(VE.getMetadataOrNullID(N->getDeclaration()));
1867   Record.push_back(VE.getMetadataOrNullID(N->getRetainedNodes().get()));
1868   Record.push_back(N->getThisAdjustment());
1869   Record.push_back(VE.getMetadataOrNullID(N->getThrownTypes().get()));
1870   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1871   Record.push_back(VE.getMetadataOrNullID(N->getRawTargetFuncName()));
1872 
1873   Stream.EmitRecord(bitc::METADATA_SUBPROGRAM, Record, Abbrev);
1874   Record.clear();
1875 }
1876 
1877 void ModuleBitcodeWriter::writeDILexicalBlock(const DILexicalBlock *N,
1878                                               SmallVectorImpl<uint64_t> &Record,
1879                                               unsigned Abbrev) {
1880   Record.push_back(N->isDistinct());
1881   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1882   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1883   Record.push_back(N->getLine());
1884   Record.push_back(N->getColumn());
1885 
1886   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK, Record, Abbrev);
1887   Record.clear();
1888 }
1889 
1890 void ModuleBitcodeWriter::writeDILexicalBlockFile(
1891     const DILexicalBlockFile *N, SmallVectorImpl<uint64_t> &Record,
1892     unsigned Abbrev) {
1893   Record.push_back(N->isDistinct());
1894   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1895   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1896   Record.push_back(N->getDiscriminator());
1897 
1898   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK_FILE, Record, Abbrev);
1899   Record.clear();
1900 }
1901 
1902 void ModuleBitcodeWriter::writeDICommonBlock(const DICommonBlock *N,
1903                                              SmallVectorImpl<uint64_t> &Record,
1904                                              unsigned Abbrev) {
1905   Record.push_back(N->isDistinct());
1906   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1907   Record.push_back(VE.getMetadataOrNullID(N->getDecl()));
1908   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1909   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1910   Record.push_back(N->getLineNo());
1911 
1912   Stream.EmitRecord(bitc::METADATA_COMMON_BLOCK, Record, Abbrev);
1913   Record.clear();
1914 }
1915 
1916 void ModuleBitcodeWriter::writeDINamespace(const DINamespace *N,
1917                                            SmallVectorImpl<uint64_t> &Record,
1918                                            unsigned Abbrev) {
1919   Record.push_back(N->isDistinct() | N->getExportSymbols() << 1);
1920   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1921   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1922 
1923   Stream.EmitRecord(bitc::METADATA_NAMESPACE, Record, Abbrev);
1924   Record.clear();
1925 }
1926 
1927 void ModuleBitcodeWriter::writeDIMacro(const DIMacro *N,
1928                                        SmallVectorImpl<uint64_t> &Record,
1929                                        unsigned Abbrev) {
1930   Record.push_back(N->isDistinct());
1931   Record.push_back(N->getMacinfoType());
1932   Record.push_back(N->getLine());
1933   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1934   Record.push_back(VE.getMetadataOrNullID(N->getRawValue()));
1935 
1936   Stream.EmitRecord(bitc::METADATA_MACRO, Record, Abbrev);
1937   Record.clear();
1938 }
1939 
1940 void ModuleBitcodeWriter::writeDIMacroFile(const DIMacroFile *N,
1941                                            SmallVectorImpl<uint64_t> &Record,
1942                                            unsigned Abbrev) {
1943   Record.push_back(N->isDistinct());
1944   Record.push_back(N->getMacinfoType());
1945   Record.push_back(N->getLine());
1946   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1947   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1948 
1949   Stream.EmitRecord(bitc::METADATA_MACRO_FILE, Record, Abbrev);
1950   Record.clear();
1951 }
1952 
1953 void ModuleBitcodeWriter::writeDIArgList(const DIArgList *N,
1954                                          SmallVectorImpl<uint64_t> &Record,
1955                                          unsigned Abbrev) {
1956   Record.reserve(N->getArgs().size());
1957   for (ValueAsMetadata *MD : N->getArgs())
1958     Record.push_back(VE.getMetadataID(MD));
1959 
1960   Stream.EmitRecord(bitc::METADATA_ARG_LIST, Record, Abbrev);
1961   Record.clear();
1962 }
1963 
1964 void ModuleBitcodeWriter::writeDIModule(const DIModule *N,
1965                                         SmallVectorImpl<uint64_t> &Record,
1966                                         unsigned Abbrev) {
1967   Record.push_back(N->isDistinct());
1968   for (auto &I : N->operands())
1969     Record.push_back(VE.getMetadataOrNullID(I));
1970   Record.push_back(N->getLineNo());
1971   Record.push_back(N->getIsDecl());
1972 
1973   Stream.EmitRecord(bitc::METADATA_MODULE, Record, Abbrev);
1974   Record.clear();
1975 }
1976 
1977 void ModuleBitcodeWriter::writeDIAssignID(const DIAssignID *N,
1978                                           SmallVectorImpl<uint64_t> &Record,
1979                                           unsigned Abbrev) {
1980   // There are no arguments for this metadata type.
1981   Record.push_back(N->isDistinct());
1982   Stream.EmitRecord(bitc::METADATA_ASSIGN_ID, Record, Abbrev);
1983   Record.clear();
1984 }
1985 
1986 void ModuleBitcodeWriter::writeDITemplateTypeParameter(
1987     const DITemplateTypeParameter *N, SmallVectorImpl<uint64_t> &Record,
1988     unsigned Abbrev) {
1989   Record.push_back(N->isDistinct());
1990   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1991   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1992   Record.push_back(N->isDefault());
1993 
1994   Stream.EmitRecord(bitc::METADATA_TEMPLATE_TYPE, Record, Abbrev);
1995   Record.clear();
1996 }
1997 
1998 void ModuleBitcodeWriter::writeDITemplateValueParameter(
1999     const DITemplateValueParameter *N, SmallVectorImpl<uint64_t> &Record,
2000     unsigned Abbrev) {
2001   Record.push_back(N->isDistinct());
2002   Record.push_back(N->getTag());
2003   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2004   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2005   Record.push_back(N->isDefault());
2006   Record.push_back(VE.getMetadataOrNullID(N->getValue()));
2007 
2008   Stream.EmitRecord(bitc::METADATA_TEMPLATE_VALUE, Record, Abbrev);
2009   Record.clear();
2010 }
2011 
2012 void ModuleBitcodeWriter::writeDIGlobalVariable(
2013     const DIGlobalVariable *N, SmallVectorImpl<uint64_t> &Record,
2014     unsigned Abbrev) {
2015   const uint64_t Version = 2 << 1;
2016   Record.push_back((uint64_t)N->isDistinct() | Version);
2017   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2018   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2019   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
2020   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2021   Record.push_back(N->getLine());
2022   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2023   Record.push_back(N->isLocalToUnit());
2024   Record.push_back(N->isDefinition());
2025   Record.push_back(VE.getMetadataOrNullID(N->getStaticDataMemberDeclaration()));
2026   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams()));
2027   Record.push_back(N->getAlignInBits());
2028   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
2029 
2030   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR, Record, Abbrev);
2031   Record.clear();
2032 }
2033 
2034 void ModuleBitcodeWriter::writeDILocalVariable(
2035     const DILocalVariable *N, SmallVectorImpl<uint64_t> &Record,
2036     unsigned Abbrev) {
2037   // In order to support all possible bitcode formats in BitcodeReader we need
2038   // to distinguish the following cases:
2039   // 1) Record has no artificial tag (Record[1]),
2040   //   has no obsolete inlinedAt field (Record[9]).
2041   //   In this case Record size will be 8, HasAlignment flag is false.
2042   // 2) Record has artificial tag (Record[1]),
2043   //   has no obsolete inlignedAt field (Record[9]).
2044   //   In this case Record size will be 9, HasAlignment flag is false.
2045   // 3) Record has both artificial tag (Record[1]) and
2046   //   obsolete inlignedAt field (Record[9]).
2047   //   In this case Record size will be 10, HasAlignment flag is false.
2048   // 4) Record has neither artificial tag, nor inlignedAt field, but
2049   //   HasAlignment flag is true and Record[8] contains alignment value.
2050   const uint64_t HasAlignmentFlag = 1 << 1;
2051   Record.push_back((uint64_t)N->isDistinct() | HasAlignmentFlag);
2052   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2053   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2054   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2055   Record.push_back(N->getLine());
2056   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2057   Record.push_back(N->getArg());
2058   Record.push_back(N->getFlags());
2059   Record.push_back(N->getAlignInBits());
2060   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
2061 
2062   Stream.EmitRecord(bitc::METADATA_LOCAL_VAR, Record, Abbrev);
2063   Record.clear();
2064 }
2065 
2066 void ModuleBitcodeWriter::writeDILabel(
2067     const DILabel *N, SmallVectorImpl<uint64_t> &Record,
2068     unsigned Abbrev) {
2069   Record.push_back((uint64_t)N->isDistinct());
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 
2075   Stream.EmitRecord(bitc::METADATA_LABEL, Record, Abbrev);
2076   Record.clear();
2077 }
2078 
2079 void ModuleBitcodeWriter::writeDIExpression(const DIExpression *N,
2080                                             SmallVectorImpl<uint64_t> &Record,
2081                                             unsigned Abbrev) {
2082   Record.reserve(N->getElements().size() + 1);
2083   const uint64_t Version = 3 << 1;
2084   Record.push_back((uint64_t)N->isDistinct() | Version);
2085   Record.append(N->elements_begin(), N->elements_end());
2086 
2087   Stream.EmitRecord(bitc::METADATA_EXPRESSION, Record, Abbrev);
2088   Record.clear();
2089 }
2090 
2091 void ModuleBitcodeWriter::writeDIGlobalVariableExpression(
2092     const DIGlobalVariableExpression *N, SmallVectorImpl<uint64_t> &Record,
2093     unsigned Abbrev) {
2094   Record.push_back(N->isDistinct());
2095   Record.push_back(VE.getMetadataOrNullID(N->getVariable()));
2096   Record.push_back(VE.getMetadataOrNullID(N->getExpression()));
2097 
2098   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR_EXPR, Record, Abbrev);
2099   Record.clear();
2100 }
2101 
2102 void ModuleBitcodeWriter::writeDIObjCProperty(const DIObjCProperty *N,
2103                                               SmallVectorImpl<uint64_t> &Record,
2104                                               unsigned Abbrev) {
2105   Record.push_back(N->isDistinct());
2106   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2107   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2108   Record.push_back(N->getLine());
2109   Record.push_back(VE.getMetadataOrNullID(N->getRawSetterName()));
2110   Record.push_back(VE.getMetadataOrNullID(N->getRawGetterName()));
2111   Record.push_back(N->getAttributes());
2112   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2113 
2114   Stream.EmitRecord(bitc::METADATA_OBJC_PROPERTY, Record, Abbrev);
2115   Record.clear();
2116 }
2117 
2118 void ModuleBitcodeWriter::writeDIImportedEntity(
2119     const DIImportedEntity *N, SmallVectorImpl<uint64_t> &Record,
2120     unsigned Abbrev) {
2121   Record.push_back(N->isDistinct());
2122   Record.push_back(N->getTag());
2123   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2124   Record.push_back(VE.getMetadataOrNullID(N->getEntity()));
2125   Record.push_back(N->getLine());
2126   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2127   Record.push_back(VE.getMetadataOrNullID(N->getRawFile()));
2128   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
2129 
2130   Stream.EmitRecord(bitc::METADATA_IMPORTED_ENTITY, Record, Abbrev);
2131   Record.clear();
2132 }
2133 
2134 unsigned ModuleBitcodeWriter::createNamedMetadataAbbrev() {
2135   auto Abbv = std::make_shared<BitCodeAbbrev>();
2136   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
2137   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2138   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2139   return Stream.EmitAbbrev(std::move(Abbv));
2140 }
2141 
2142 void ModuleBitcodeWriter::writeNamedMetadata(
2143     SmallVectorImpl<uint64_t> &Record) {
2144   if (M.named_metadata_empty())
2145     return;
2146 
2147   unsigned Abbrev = createNamedMetadataAbbrev();
2148   for (const NamedMDNode &NMD : M.named_metadata()) {
2149     // Write name.
2150     StringRef Str = NMD.getName();
2151     Record.append(Str.bytes_begin(), Str.bytes_end());
2152     Stream.EmitRecord(bitc::METADATA_NAME, Record, Abbrev);
2153     Record.clear();
2154 
2155     // Write named metadata operands.
2156     for (const MDNode *N : NMD.operands())
2157       Record.push_back(VE.getMetadataID(N));
2158     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
2159     Record.clear();
2160   }
2161 }
2162 
2163 unsigned ModuleBitcodeWriter::createMetadataStringsAbbrev() {
2164   auto Abbv = std::make_shared<BitCodeAbbrev>();
2165   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRINGS));
2166   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // # of strings
2167   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // offset to chars
2168   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
2169   return Stream.EmitAbbrev(std::move(Abbv));
2170 }
2171 
2172 /// Write out a record for MDString.
2173 ///
2174 /// All the metadata strings in a metadata block are emitted in a single
2175 /// record.  The sizes and strings themselves are shoved into a blob.
2176 void ModuleBitcodeWriter::writeMetadataStrings(
2177     ArrayRef<const Metadata *> Strings, SmallVectorImpl<uint64_t> &Record) {
2178   if (Strings.empty())
2179     return;
2180 
2181   // Start the record with the number of strings.
2182   Record.push_back(bitc::METADATA_STRINGS);
2183   Record.push_back(Strings.size());
2184 
2185   // Emit the sizes of the strings in the blob.
2186   SmallString<256> Blob;
2187   {
2188     BitstreamWriter W(Blob);
2189     for (const Metadata *MD : Strings)
2190       W.EmitVBR(cast<MDString>(MD)->getLength(), 6);
2191     W.FlushToWord();
2192   }
2193 
2194   // Add the offset to the strings to the record.
2195   Record.push_back(Blob.size());
2196 
2197   // Add the strings to the blob.
2198   for (const Metadata *MD : Strings)
2199     Blob.append(cast<MDString>(MD)->getString());
2200 
2201   // Emit the final record.
2202   Stream.EmitRecordWithBlob(createMetadataStringsAbbrev(), Record, Blob);
2203   Record.clear();
2204 }
2205 
2206 // Generates an enum to use as an index in the Abbrev array of Metadata record.
2207 enum MetadataAbbrev : unsigned {
2208 #define HANDLE_MDNODE_LEAF(CLASS) CLASS##AbbrevID,
2209 #include "llvm/IR/Metadata.def"
2210   LastPlusOne
2211 };
2212 
2213 void ModuleBitcodeWriter::writeMetadataRecords(
2214     ArrayRef<const Metadata *> MDs, SmallVectorImpl<uint64_t> &Record,
2215     std::vector<unsigned> *MDAbbrevs, std::vector<uint64_t> *IndexPos) {
2216   if (MDs.empty())
2217     return;
2218 
2219   // Initialize MDNode abbreviations.
2220 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
2221 #include "llvm/IR/Metadata.def"
2222 
2223   for (const Metadata *MD : MDs) {
2224     if (IndexPos)
2225       IndexPos->push_back(Stream.GetCurrentBitNo());
2226     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
2227       assert(N->isResolved() && "Expected forward references to be resolved");
2228 
2229       switch (N->getMetadataID()) {
2230       default:
2231         llvm_unreachable("Invalid MDNode subclass");
2232 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
2233   case Metadata::CLASS##Kind:                                                  \
2234     if (MDAbbrevs)                                                             \
2235       write##CLASS(cast<CLASS>(N), Record,                                     \
2236                    (*MDAbbrevs)[MetadataAbbrev::CLASS##AbbrevID]);             \
2237     else                                                                       \
2238       write##CLASS(cast<CLASS>(N), Record, CLASS##Abbrev);                     \
2239     continue;
2240 #include "llvm/IR/Metadata.def"
2241       }
2242     }
2243     writeValueAsMetadata(cast<ValueAsMetadata>(MD), Record);
2244   }
2245 }
2246 
2247 void ModuleBitcodeWriter::writeModuleMetadata() {
2248   if (!VE.hasMDs() && M.named_metadata_empty())
2249     return;
2250 
2251   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 4);
2252   SmallVector<uint64_t, 64> Record;
2253 
2254   // Emit all abbrevs upfront, so that the reader can jump in the middle of the
2255   // block and load any metadata.
2256   std::vector<unsigned> MDAbbrevs;
2257 
2258   MDAbbrevs.resize(MetadataAbbrev::LastPlusOne);
2259   MDAbbrevs[MetadataAbbrev::DILocationAbbrevID] = createDILocationAbbrev();
2260   MDAbbrevs[MetadataAbbrev::GenericDINodeAbbrevID] =
2261       createGenericDINodeAbbrev();
2262 
2263   auto Abbv = std::make_shared<BitCodeAbbrev>();
2264   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX_OFFSET));
2265   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2266   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2267   unsigned OffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2268 
2269   Abbv = std::make_shared<BitCodeAbbrev>();
2270   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX));
2271   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2272   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2273   unsigned IndexAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2274 
2275   // Emit MDStrings together upfront.
2276   writeMetadataStrings(VE.getMDStrings(), Record);
2277 
2278   // We only emit an index for the metadata record if we have more than a given
2279   // (naive) threshold of metadatas, otherwise it is not worth it.
2280   if (VE.getNonMDStrings().size() > IndexThreshold) {
2281     // Write a placeholder value in for the offset of the metadata index,
2282     // which is written after the records, so that it can include
2283     // the offset of each entry. The placeholder offset will be
2284     // updated after all records are emitted.
2285     uint64_t Vals[] = {0, 0};
2286     Stream.EmitRecord(bitc::METADATA_INDEX_OFFSET, Vals, OffsetAbbrev);
2287   }
2288 
2289   // Compute and save the bit offset to the current position, which will be
2290   // patched when we emit the index later. We can simply subtract the 64-bit
2291   // fixed size from the current bit number to get the location to backpatch.
2292   uint64_t IndexOffsetRecordBitPos = Stream.GetCurrentBitNo();
2293 
2294   // This index will contain the bitpos for each individual record.
2295   std::vector<uint64_t> IndexPos;
2296   IndexPos.reserve(VE.getNonMDStrings().size());
2297 
2298   // Write all the records
2299   writeMetadataRecords(VE.getNonMDStrings(), Record, &MDAbbrevs, &IndexPos);
2300 
2301   if (VE.getNonMDStrings().size() > IndexThreshold) {
2302     // Now that we have emitted all the records we will emit the index. But
2303     // first
2304     // backpatch the forward reference so that the reader can skip the records
2305     // efficiently.
2306     Stream.BackpatchWord64(IndexOffsetRecordBitPos - 64,
2307                            Stream.GetCurrentBitNo() - IndexOffsetRecordBitPos);
2308 
2309     // Delta encode the index.
2310     uint64_t PreviousValue = IndexOffsetRecordBitPos;
2311     for (auto &Elt : IndexPos) {
2312       auto EltDelta = Elt - PreviousValue;
2313       PreviousValue = Elt;
2314       Elt = EltDelta;
2315     }
2316     // Emit the index record.
2317     Stream.EmitRecord(bitc::METADATA_INDEX, IndexPos, IndexAbbrev);
2318     IndexPos.clear();
2319   }
2320 
2321   // Write the named metadata now.
2322   writeNamedMetadata(Record);
2323 
2324   auto AddDeclAttachedMetadata = [&](const GlobalObject &GO) {
2325     SmallVector<uint64_t, 4> Record;
2326     Record.push_back(VE.getValueID(&GO));
2327     pushGlobalMetadataAttachment(Record, GO);
2328     Stream.EmitRecord(bitc::METADATA_GLOBAL_DECL_ATTACHMENT, Record);
2329   };
2330   for (const Function &F : M)
2331     if (F.isDeclaration() && F.hasMetadata())
2332       AddDeclAttachedMetadata(F);
2333   // FIXME: Only store metadata for declarations here, and move data for global
2334   // variable definitions to a separate block (PR28134).
2335   for (const GlobalVariable &GV : M.globals())
2336     if (GV.hasMetadata())
2337       AddDeclAttachedMetadata(GV);
2338 
2339   Stream.ExitBlock();
2340 }
2341 
2342 void ModuleBitcodeWriter::writeFunctionMetadata(const Function &F) {
2343   if (!VE.hasMDs())
2344     return;
2345 
2346   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
2347   SmallVector<uint64_t, 64> Record;
2348   writeMetadataStrings(VE.getMDStrings(), Record);
2349   writeMetadataRecords(VE.getNonMDStrings(), Record);
2350   Stream.ExitBlock();
2351 }
2352 
2353 void ModuleBitcodeWriter::pushGlobalMetadataAttachment(
2354     SmallVectorImpl<uint64_t> &Record, const GlobalObject &GO) {
2355   // [n x [id, mdnode]]
2356   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2357   GO.getAllMetadata(MDs);
2358   for (const auto &I : MDs) {
2359     Record.push_back(I.first);
2360     Record.push_back(VE.getMetadataID(I.second));
2361   }
2362 }
2363 
2364 void ModuleBitcodeWriter::writeFunctionMetadataAttachment(const Function &F) {
2365   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
2366 
2367   SmallVector<uint64_t, 64> Record;
2368 
2369   if (F.hasMetadata()) {
2370     pushGlobalMetadataAttachment(Record, F);
2371     Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2372     Record.clear();
2373   }
2374 
2375   // Write metadata attachments
2376   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
2377   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2378   for (const BasicBlock &BB : F)
2379     for (const Instruction &I : BB) {
2380       MDs.clear();
2381       I.getAllMetadataOtherThanDebugLoc(MDs);
2382 
2383       // If no metadata, ignore instruction.
2384       if (MDs.empty()) continue;
2385 
2386       Record.push_back(VE.getInstructionID(&I));
2387 
2388       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
2389         Record.push_back(MDs[i].first);
2390         Record.push_back(VE.getMetadataID(MDs[i].second));
2391       }
2392       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2393       Record.clear();
2394     }
2395 
2396   Stream.ExitBlock();
2397 }
2398 
2399 void ModuleBitcodeWriter::writeModuleMetadataKinds() {
2400   SmallVector<uint64_t, 64> Record;
2401 
2402   // Write metadata kinds
2403   // METADATA_KIND - [n x [id, name]]
2404   SmallVector<StringRef, 8> Names;
2405   M.getMDKindNames(Names);
2406 
2407   if (Names.empty()) return;
2408 
2409   Stream.EnterSubblock(bitc::METADATA_KIND_BLOCK_ID, 3);
2410 
2411   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
2412     Record.push_back(MDKindID);
2413     StringRef KName = Names[MDKindID];
2414     Record.append(KName.begin(), KName.end());
2415 
2416     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
2417     Record.clear();
2418   }
2419 
2420   Stream.ExitBlock();
2421 }
2422 
2423 void ModuleBitcodeWriter::writeOperandBundleTags() {
2424   // Write metadata kinds
2425   //
2426   // OPERAND_BUNDLE_TAGS_BLOCK_ID : N x OPERAND_BUNDLE_TAG
2427   //
2428   // OPERAND_BUNDLE_TAG - [strchr x N]
2429 
2430   SmallVector<StringRef, 8> Tags;
2431   M.getOperandBundleTags(Tags);
2432 
2433   if (Tags.empty())
2434     return;
2435 
2436   Stream.EnterSubblock(bitc::OPERAND_BUNDLE_TAGS_BLOCK_ID, 3);
2437 
2438   SmallVector<uint64_t, 64> Record;
2439 
2440   for (auto Tag : Tags) {
2441     Record.append(Tag.begin(), Tag.end());
2442 
2443     Stream.EmitRecord(bitc::OPERAND_BUNDLE_TAG, Record, 0);
2444     Record.clear();
2445   }
2446 
2447   Stream.ExitBlock();
2448 }
2449 
2450 void ModuleBitcodeWriter::writeSyncScopeNames() {
2451   SmallVector<StringRef, 8> SSNs;
2452   M.getContext().getSyncScopeNames(SSNs);
2453   if (SSNs.empty())
2454     return;
2455 
2456   Stream.EnterSubblock(bitc::SYNC_SCOPE_NAMES_BLOCK_ID, 2);
2457 
2458   SmallVector<uint64_t, 64> Record;
2459   for (auto SSN : SSNs) {
2460     Record.append(SSN.begin(), SSN.end());
2461     Stream.EmitRecord(bitc::SYNC_SCOPE_NAME, Record, 0);
2462     Record.clear();
2463   }
2464 
2465   Stream.ExitBlock();
2466 }
2467 
2468 void ModuleBitcodeWriter::writeConstants(unsigned FirstVal, unsigned LastVal,
2469                                          bool isGlobal) {
2470   if (FirstVal == LastVal) return;
2471 
2472   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
2473 
2474   unsigned AggregateAbbrev = 0;
2475   unsigned String8Abbrev = 0;
2476   unsigned CString7Abbrev = 0;
2477   unsigned CString6Abbrev = 0;
2478   // If this is a constant pool for the module, emit module-specific abbrevs.
2479   if (isGlobal) {
2480     // Abbrev for CST_CODE_AGGREGATE.
2481     auto Abbv = std::make_shared<BitCodeAbbrev>();
2482     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
2483     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2484     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
2485     AggregateAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2486 
2487     // Abbrev for CST_CODE_STRING.
2488     Abbv = std::make_shared<BitCodeAbbrev>();
2489     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
2490     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2491     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2492     String8Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2493     // Abbrev for CST_CODE_CSTRING.
2494     Abbv = std::make_shared<BitCodeAbbrev>();
2495     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2496     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2497     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2498     CString7Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2499     // Abbrev for CST_CODE_CSTRING.
2500     Abbv = std::make_shared<BitCodeAbbrev>();
2501     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2502     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2503     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2504     CString6Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2505   }
2506 
2507   SmallVector<uint64_t, 64> Record;
2508 
2509   const ValueEnumerator::ValueList &Vals = VE.getValues();
2510   Type *LastTy = nullptr;
2511   for (unsigned i = FirstVal; i != LastVal; ++i) {
2512     const Value *V = Vals[i].first;
2513     // If we need to switch types, do so now.
2514     if (V->getType() != LastTy) {
2515       LastTy = V->getType();
2516       Record.push_back(VE.getTypeID(LastTy));
2517       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
2518                         CONSTANTS_SETTYPE_ABBREV);
2519       Record.clear();
2520     }
2521 
2522     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
2523       Record.push_back(VE.getTypeID(IA->getFunctionType()));
2524       Record.push_back(
2525           unsigned(IA->hasSideEffects()) | unsigned(IA->isAlignStack()) << 1 |
2526           unsigned(IA->getDialect() & 1) << 2 | unsigned(IA->canThrow()) << 3);
2527 
2528       // Add the asm string.
2529       const std::string &AsmStr = IA->getAsmString();
2530       Record.push_back(AsmStr.size());
2531       Record.append(AsmStr.begin(), AsmStr.end());
2532 
2533       // Add the constraint string.
2534       const std::string &ConstraintStr = IA->getConstraintString();
2535       Record.push_back(ConstraintStr.size());
2536       Record.append(ConstraintStr.begin(), ConstraintStr.end());
2537       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
2538       Record.clear();
2539       continue;
2540     }
2541     const Constant *C = cast<Constant>(V);
2542     unsigned Code = -1U;
2543     unsigned AbbrevToUse = 0;
2544     if (C->isNullValue()) {
2545       Code = bitc::CST_CODE_NULL;
2546     } else if (isa<PoisonValue>(C)) {
2547       Code = bitc::CST_CODE_POISON;
2548     } else if (isa<UndefValue>(C)) {
2549       Code = bitc::CST_CODE_UNDEF;
2550     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
2551       if (IV->getBitWidth() <= 64) {
2552         uint64_t V = IV->getSExtValue();
2553         emitSignedInt64(Record, V);
2554         Code = bitc::CST_CODE_INTEGER;
2555         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
2556       } else {                             // Wide integers, > 64 bits in size.
2557         emitWideAPInt(Record, IV->getValue());
2558         Code = bitc::CST_CODE_WIDE_INTEGER;
2559       }
2560     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
2561       Code = bitc::CST_CODE_FLOAT;
2562       Type *Ty = CFP->getType();
2563       if (Ty->isHalfTy() || Ty->isBFloatTy() || Ty->isFloatTy() ||
2564           Ty->isDoubleTy()) {
2565         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
2566       } else if (Ty->isX86_FP80Ty()) {
2567         // api needed to prevent premature destruction
2568         // bits are not in the same order as a normal i80 APInt, compensate.
2569         APInt api = CFP->getValueAPF().bitcastToAPInt();
2570         const uint64_t *p = api.getRawData();
2571         Record.push_back((p[1] << 48) | (p[0] >> 16));
2572         Record.push_back(p[0] & 0xffffLL);
2573       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
2574         APInt api = CFP->getValueAPF().bitcastToAPInt();
2575         const uint64_t *p = api.getRawData();
2576         Record.push_back(p[0]);
2577         Record.push_back(p[1]);
2578       } else {
2579         assert(0 && "Unknown FP type!");
2580       }
2581     } else if (isa<ConstantDataSequential>(C) &&
2582                cast<ConstantDataSequential>(C)->isString()) {
2583       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
2584       // Emit constant strings specially.
2585       unsigned NumElts = Str->getNumElements();
2586       // If this is a null-terminated string, use the denser CSTRING encoding.
2587       if (Str->isCString()) {
2588         Code = bitc::CST_CODE_CSTRING;
2589         --NumElts;  // Don't encode the null, which isn't allowed by char6.
2590       } else {
2591         Code = bitc::CST_CODE_STRING;
2592         AbbrevToUse = String8Abbrev;
2593       }
2594       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
2595       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
2596       for (unsigned i = 0; i != NumElts; ++i) {
2597         unsigned char V = Str->getElementAsInteger(i);
2598         Record.push_back(V);
2599         isCStr7 &= (V & 128) == 0;
2600         if (isCStrChar6)
2601           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
2602       }
2603 
2604       if (isCStrChar6)
2605         AbbrevToUse = CString6Abbrev;
2606       else if (isCStr7)
2607         AbbrevToUse = CString7Abbrev;
2608     } else if (const ConstantDataSequential *CDS =
2609                   dyn_cast<ConstantDataSequential>(C)) {
2610       Code = bitc::CST_CODE_DATA;
2611       Type *EltTy = CDS->getElementType();
2612       if (isa<IntegerType>(EltTy)) {
2613         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2614           Record.push_back(CDS->getElementAsInteger(i));
2615       } else {
2616         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2617           Record.push_back(
2618               CDS->getElementAsAPFloat(i).bitcastToAPInt().getLimitedValue());
2619       }
2620     } else if (isa<ConstantAggregate>(C)) {
2621       Code = bitc::CST_CODE_AGGREGATE;
2622       for (const Value *Op : C->operands())
2623         Record.push_back(VE.getValueID(Op));
2624       AbbrevToUse = AggregateAbbrev;
2625     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
2626       switch (CE->getOpcode()) {
2627       default:
2628         if (Instruction::isCast(CE->getOpcode())) {
2629           Code = bitc::CST_CODE_CE_CAST;
2630           Record.push_back(getEncodedCastOpcode(CE->getOpcode()));
2631           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2632           Record.push_back(VE.getValueID(C->getOperand(0)));
2633           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
2634         } else {
2635           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
2636           Code = bitc::CST_CODE_CE_BINOP;
2637           Record.push_back(getEncodedBinaryOpcode(CE->getOpcode()));
2638           Record.push_back(VE.getValueID(C->getOperand(0)));
2639           Record.push_back(VE.getValueID(C->getOperand(1)));
2640           uint64_t Flags = getOptimizationFlags(CE);
2641           if (Flags != 0)
2642             Record.push_back(Flags);
2643         }
2644         break;
2645       case Instruction::FNeg: {
2646         assert(CE->getNumOperands() == 1 && "Unknown constant expr!");
2647         Code = bitc::CST_CODE_CE_UNOP;
2648         Record.push_back(getEncodedUnaryOpcode(CE->getOpcode()));
2649         Record.push_back(VE.getValueID(C->getOperand(0)));
2650         uint64_t Flags = getOptimizationFlags(CE);
2651         if (Flags != 0)
2652           Record.push_back(Flags);
2653         break;
2654       }
2655       case Instruction::GetElementPtr: {
2656         Code = bitc::CST_CODE_CE_GEP;
2657         const auto *GO = cast<GEPOperator>(C);
2658         Record.push_back(VE.getTypeID(GO->getSourceElementType()));
2659         if (std::optional<unsigned> Idx = GO->getInRangeIndex()) {
2660           Code = bitc::CST_CODE_CE_GEP_WITH_INRANGE_INDEX;
2661           Record.push_back((*Idx << 1) | GO->isInBounds());
2662         } else if (GO->isInBounds())
2663           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
2664         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
2665           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
2666           Record.push_back(VE.getValueID(C->getOperand(i)));
2667         }
2668         break;
2669       }
2670       case Instruction::Select:
2671         Code = bitc::CST_CODE_CE_SELECT;
2672         Record.push_back(VE.getValueID(C->getOperand(0)));
2673         Record.push_back(VE.getValueID(C->getOperand(1)));
2674         Record.push_back(VE.getValueID(C->getOperand(2)));
2675         break;
2676       case Instruction::ExtractElement:
2677         Code = bitc::CST_CODE_CE_EXTRACTELT;
2678         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2679         Record.push_back(VE.getValueID(C->getOperand(0)));
2680         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
2681         Record.push_back(VE.getValueID(C->getOperand(1)));
2682         break;
2683       case Instruction::InsertElement:
2684         Code = bitc::CST_CODE_CE_INSERTELT;
2685         Record.push_back(VE.getValueID(C->getOperand(0)));
2686         Record.push_back(VE.getValueID(C->getOperand(1)));
2687         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
2688         Record.push_back(VE.getValueID(C->getOperand(2)));
2689         break;
2690       case Instruction::ShuffleVector:
2691         // If the return type and argument types are the same, this is a
2692         // standard shufflevector instruction.  If the types are different,
2693         // then the shuffle is widening or truncating the input vectors, and
2694         // the argument type must also be encoded.
2695         if (C->getType() == C->getOperand(0)->getType()) {
2696           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
2697         } else {
2698           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
2699           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2700         }
2701         Record.push_back(VE.getValueID(C->getOperand(0)));
2702         Record.push_back(VE.getValueID(C->getOperand(1)));
2703         Record.push_back(VE.getValueID(CE->getShuffleMaskForBitcode()));
2704         break;
2705       case Instruction::ICmp:
2706       case Instruction::FCmp:
2707         Code = bitc::CST_CODE_CE_CMP;
2708         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2709         Record.push_back(VE.getValueID(C->getOperand(0)));
2710         Record.push_back(VE.getValueID(C->getOperand(1)));
2711         Record.push_back(CE->getPredicate());
2712         break;
2713       }
2714     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
2715       Code = bitc::CST_CODE_BLOCKADDRESS;
2716       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
2717       Record.push_back(VE.getValueID(BA->getFunction()));
2718       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
2719     } else if (const auto *Equiv = dyn_cast<DSOLocalEquivalent>(C)) {
2720       Code = bitc::CST_CODE_DSO_LOCAL_EQUIVALENT;
2721       Record.push_back(VE.getTypeID(Equiv->getGlobalValue()->getType()));
2722       Record.push_back(VE.getValueID(Equiv->getGlobalValue()));
2723     } else if (const auto *NC = dyn_cast<NoCFIValue>(C)) {
2724       Code = bitc::CST_CODE_NO_CFI_VALUE;
2725       Record.push_back(VE.getTypeID(NC->getGlobalValue()->getType()));
2726       Record.push_back(VE.getValueID(NC->getGlobalValue()));
2727     } else {
2728 #ifndef NDEBUG
2729       C->dump();
2730 #endif
2731       llvm_unreachable("Unknown constant!");
2732     }
2733     Stream.EmitRecord(Code, Record, AbbrevToUse);
2734     Record.clear();
2735   }
2736 
2737   Stream.ExitBlock();
2738 }
2739 
2740 void ModuleBitcodeWriter::writeModuleConstants() {
2741   const ValueEnumerator::ValueList &Vals = VE.getValues();
2742 
2743   // Find the first constant to emit, which is the first non-globalvalue value.
2744   // We know globalvalues have been emitted by WriteModuleInfo.
2745   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
2746     if (!isa<GlobalValue>(Vals[i].first)) {
2747       writeConstants(i, Vals.size(), true);
2748       return;
2749     }
2750   }
2751 }
2752 
2753 /// pushValueAndType - The file has to encode both the value and type id for
2754 /// many values, because we need to know what type to create for forward
2755 /// references.  However, most operands are not forward references, so this type
2756 /// field is not needed.
2757 ///
2758 /// This function adds V's value ID to Vals.  If the value ID is higher than the
2759 /// instruction ID, then it is a forward reference, and it also includes the
2760 /// type ID.  The value ID that is written is encoded relative to the InstID.
2761 bool ModuleBitcodeWriter::pushValueAndType(const Value *V, unsigned InstID,
2762                                            SmallVectorImpl<unsigned> &Vals) {
2763   unsigned ValID = VE.getValueID(V);
2764   // Make encoding relative to the InstID.
2765   Vals.push_back(InstID - ValID);
2766   if (ValID >= InstID) {
2767     Vals.push_back(VE.getTypeID(V->getType()));
2768     return true;
2769   }
2770   return false;
2771 }
2772 
2773 void ModuleBitcodeWriter::writeOperandBundles(const CallBase &CS,
2774                                               unsigned InstID) {
2775   SmallVector<unsigned, 64> Record;
2776   LLVMContext &C = CS.getContext();
2777 
2778   for (unsigned i = 0, e = CS.getNumOperandBundles(); i != e; ++i) {
2779     const auto &Bundle = CS.getOperandBundleAt(i);
2780     Record.push_back(C.getOperandBundleTagID(Bundle.getTagName()));
2781 
2782     for (auto &Input : Bundle.Inputs)
2783       pushValueAndType(Input, InstID, Record);
2784 
2785     Stream.EmitRecord(bitc::FUNC_CODE_OPERAND_BUNDLE, Record);
2786     Record.clear();
2787   }
2788 }
2789 
2790 /// pushValue - Like pushValueAndType, but where the type of the value is
2791 /// omitted (perhaps it was already encoded in an earlier operand).
2792 void ModuleBitcodeWriter::pushValue(const Value *V, unsigned InstID,
2793                                     SmallVectorImpl<unsigned> &Vals) {
2794   unsigned ValID = VE.getValueID(V);
2795   Vals.push_back(InstID - ValID);
2796 }
2797 
2798 void ModuleBitcodeWriter::pushValueSigned(const Value *V, unsigned InstID,
2799                                           SmallVectorImpl<uint64_t> &Vals) {
2800   unsigned ValID = VE.getValueID(V);
2801   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
2802   emitSignedInt64(Vals, diff);
2803 }
2804 
2805 /// WriteInstruction - Emit an instruction to the specified stream.
2806 void ModuleBitcodeWriter::writeInstruction(const Instruction &I,
2807                                            unsigned InstID,
2808                                            SmallVectorImpl<unsigned> &Vals) {
2809   unsigned Code = 0;
2810   unsigned AbbrevToUse = 0;
2811   VE.setInstructionID(&I);
2812   switch (I.getOpcode()) {
2813   default:
2814     if (Instruction::isCast(I.getOpcode())) {
2815       Code = bitc::FUNC_CODE_INST_CAST;
2816       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2817         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
2818       Vals.push_back(VE.getTypeID(I.getType()));
2819       Vals.push_back(getEncodedCastOpcode(I.getOpcode()));
2820     } else {
2821       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
2822       Code = bitc::FUNC_CODE_INST_BINOP;
2823       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2824         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
2825       pushValue(I.getOperand(1), InstID, Vals);
2826       Vals.push_back(getEncodedBinaryOpcode(I.getOpcode()));
2827       uint64_t Flags = getOptimizationFlags(&I);
2828       if (Flags != 0) {
2829         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
2830           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
2831         Vals.push_back(Flags);
2832       }
2833     }
2834     break;
2835   case Instruction::FNeg: {
2836     Code = bitc::FUNC_CODE_INST_UNOP;
2837     if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2838       AbbrevToUse = FUNCTION_INST_UNOP_ABBREV;
2839     Vals.push_back(getEncodedUnaryOpcode(I.getOpcode()));
2840     uint64_t Flags = getOptimizationFlags(&I);
2841     if (Flags != 0) {
2842       if (AbbrevToUse == FUNCTION_INST_UNOP_ABBREV)
2843         AbbrevToUse = FUNCTION_INST_UNOP_FLAGS_ABBREV;
2844       Vals.push_back(Flags);
2845     }
2846     break;
2847   }
2848   case Instruction::GetElementPtr: {
2849     Code = bitc::FUNC_CODE_INST_GEP;
2850     AbbrevToUse = FUNCTION_INST_GEP_ABBREV;
2851     auto &GEPInst = cast<GetElementPtrInst>(I);
2852     Vals.push_back(GEPInst.isInBounds());
2853     Vals.push_back(VE.getTypeID(GEPInst.getSourceElementType()));
2854     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
2855       pushValueAndType(I.getOperand(i), InstID, Vals);
2856     break;
2857   }
2858   case Instruction::ExtractValue: {
2859     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
2860     pushValueAndType(I.getOperand(0), InstID, Vals);
2861     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
2862     Vals.append(EVI->idx_begin(), EVI->idx_end());
2863     break;
2864   }
2865   case Instruction::InsertValue: {
2866     Code = bitc::FUNC_CODE_INST_INSERTVAL;
2867     pushValueAndType(I.getOperand(0), InstID, Vals);
2868     pushValueAndType(I.getOperand(1), InstID, Vals);
2869     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
2870     Vals.append(IVI->idx_begin(), IVI->idx_end());
2871     break;
2872   }
2873   case Instruction::Select: {
2874     Code = bitc::FUNC_CODE_INST_VSELECT;
2875     pushValueAndType(I.getOperand(1), InstID, Vals);
2876     pushValue(I.getOperand(2), InstID, Vals);
2877     pushValueAndType(I.getOperand(0), InstID, Vals);
2878     uint64_t Flags = getOptimizationFlags(&I);
2879     if (Flags != 0)
2880       Vals.push_back(Flags);
2881     break;
2882   }
2883   case Instruction::ExtractElement:
2884     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
2885     pushValueAndType(I.getOperand(0), InstID, Vals);
2886     pushValueAndType(I.getOperand(1), InstID, Vals);
2887     break;
2888   case Instruction::InsertElement:
2889     Code = bitc::FUNC_CODE_INST_INSERTELT;
2890     pushValueAndType(I.getOperand(0), InstID, Vals);
2891     pushValue(I.getOperand(1), InstID, Vals);
2892     pushValueAndType(I.getOperand(2), InstID, Vals);
2893     break;
2894   case Instruction::ShuffleVector:
2895     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
2896     pushValueAndType(I.getOperand(0), InstID, Vals);
2897     pushValue(I.getOperand(1), InstID, Vals);
2898     pushValue(cast<ShuffleVectorInst>(I).getShuffleMaskForBitcode(), InstID,
2899               Vals);
2900     break;
2901   case Instruction::ICmp:
2902   case Instruction::FCmp: {
2903     // compare returning Int1Ty or vector of Int1Ty
2904     Code = bitc::FUNC_CODE_INST_CMP2;
2905     pushValueAndType(I.getOperand(0), InstID, Vals);
2906     pushValue(I.getOperand(1), InstID, Vals);
2907     Vals.push_back(cast<CmpInst>(I).getPredicate());
2908     uint64_t Flags = getOptimizationFlags(&I);
2909     if (Flags != 0)
2910       Vals.push_back(Flags);
2911     break;
2912   }
2913 
2914   case Instruction::Ret:
2915     {
2916       Code = bitc::FUNC_CODE_INST_RET;
2917       unsigned NumOperands = I.getNumOperands();
2918       if (NumOperands == 0)
2919         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
2920       else if (NumOperands == 1) {
2921         if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2922           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
2923       } else {
2924         for (unsigned i = 0, e = NumOperands; i != e; ++i)
2925           pushValueAndType(I.getOperand(i), InstID, Vals);
2926       }
2927     }
2928     break;
2929   case Instruction::Br:
2930     {
2931       Code = bitc::FUNC_CODE_INST_BR;
2932       const BranchInst &II = cast<BranchInst>(I);
2933       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
2934       if (II.isConditional()) {
2935         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
2936         pushValue(II.getCondition(), InstID, Vals);
2937       }
2938     }
2939     break;
2940   case Instruction::Switch:
2941     {
2942       Code = bitc::FUNC_CODE_INST_SWITCH;
2943       const SwitchInst &SI = cast<SwitchInst>(I);
2944       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
2945       pushValue(SI.getCondition(), InstID, Vals);
2946       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
2947       for (auto Case : SI.cases()) {
2948         Vals.push_back(VE.getValueID(Case.getCaseValue()));
2949         Vals.push_back(VE.getValueID(Case.getCaseSuccessor()));
2950       }
2951     }
2952     break;
2953   case Instruction::IndirectBr:
2954     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
2955     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2956     // Encode the address operand as relative, but not the basic blocks.
2957     pushValue(I.getOperand(0), InstID, Vals);
2958     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
2959       Vals.push_back(VE.getValueID(I.getOperand(i)));
2960     break;
2961 
2962   case Instruction::Invoke: {
2963     const InvokeInst *II = cast<InvokeInst>(&I);
2964     const Value *Callee = II->getCalledOperand();
2965     FunctionType *FTy = II->getFunctionType();
2966 
2967     if (II->hasOperandBundles())
2968       writeOperandBundles(*II, InstID);
2969 
2970     Code = bitc::FUNC_CODE_INST_INVOKE;
2971 
2972     Vals.push_back(VE.getAttributeListID(II->getAttributes()));
2973     Vals.push_back(II->getCallingConv() | 1 << 13);
2974     Vals.push_back(VE.getValueID(II->getNormalDest()));
2975     Vals.push_back(VE.getValueID(II->getUnwindDest()));
2976     Vals.push_back(VE.getTypeID(FTy));
2977     pushValueAndType(Callee, InstID, Vals);
2978 
2979     // Emit value #'s for the fixed parameters.
2980     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
2981       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
2982 
2983     // Emit type/value pairs for varargs params.
2984     if (FTy->isVarArg()) {
2985       for (unsigned i = FTy->getNumParams(), e = II->arg_size(); i != e; ++i)
2986         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
2987     }
2988     break;
2989   }
2990   case Instruction::Resume:
2991     Code = bitc::FUNC_CODE_INST_RESUME;
2992     pushValueAndType(I.getOperand(0), InstID, Vals);
2993     break;
2994   case Instruction::CleanupRet: {
2995     Code = bitc::FUNC_CODE_INST_CLEANUPRET;
2996     const auto &CRI = cast<CleanupReturnInst>(I);
2997     pushValue(CRI.getCleanupPad(), InstID, Vals);
2998     if (CRI.hasUnwindDest())
2999       Vals.push_back(VE.getValueID(CRI.getUnwindDest()));
3000     break;
3001   }
3002   case Instruction::CatchRet: {
3003     Code = bitc::FUNC_CODE_INST_CATCHRET;
3004     const auto &CRI = cast<CatchReturnInst>(I);
3005     pushValue(CRI.getCatchPad(), InstID, Vals);
3006     Vals.push_back(VE.getValueID(CRI.getSuccessor()));
3007     break;
3008   }
3009   case Instruction::CleanupPad:
3010   case Instruction::CatchPad: {
3011     const auto &FuncletPad = cast<FuncletPadInst>(I);
3012     Code = isa<CatchPadInst>(FuncletPad) ? bitc::FUNC_CODE_INST_CATCHPAD
3013                                          : bitc::FUNC_CODE_INST_CLEANUPPAD;
3014     pushValue(FuncletPad.getParentPad(), InstID, Vals);
3015 
3016     unsigned NumArgOperands = FuncletPad.arg_size();
3017     Vals.push_back(NumArgOperands);
3018     for (unsigned Op = 0; Op != NumArgOperands; ++Op)
3019       pushValueAndType(FuncletPad.getArgOperand(Op), InstID, Vals);
3020     break;
3021   }
3022   case Instruction::CatchSwitch: {
3023     Code = bitc::FUNC_CODE_INST_CATCHSWITCH;
3024     const auto &CatchSwitch = cast<CatchSwitchInst>(I);
3025 
3026     pushValue(CatchSwitch.getParentPad(), InstID, Vals);
3027 
3028     unsigned NumHandlers = CatchSwitch.getNumHandlers();
3029     Vals.push_back(NumHandlers);
3030     for (const BasicBlock *CatchPadBB : CatchSwitch.handlers())
3031       Vals.push_back(VE.getValueID(CatchPadBB));
3032 
3033     if (CatchSwitch.hasUnwindDest())
3034       Vals.push_back(VE.getValueID(CatchSwitch.getUnwindDest()));
3035     break;
3036   }
3037   case Instruction::CallBr: {
3038     const CallBrInst *CBI = cast<CallBrInst>(&I);
3039     const Value *Callee = CBI->getCalledOperand();
3040     FunctionType *FTy = CBI->getFunctionType();
3041 
3042     if (CBI->hasOperandBundles())
3043       writeOperandBundles(*CBI, InstID);
3044 
3045     Code = bitc::FUNC_CODE_INST_CALLBR;
3046 
3047     Vals.push_back(VE.getAttributeListID(CBI->getAttributes()));
3048 
3049     Vals.push_back(CBI->getCallingConv() << bitc::CALL_CCONV |
3050                    1 << bitc::CALL_EXPLICIT_TYPE);
3051 
3052     Vals.push_back(VE.getValueID(CBI->getDefaultDest()));
3053     Vals.push_back(CBI->getNumIndirectDests());
3054     for (unsigned i = 0, e = CBI->getNumIndirectDests(); i != e; ++i)
3055       Vals.push_back(VE.getValueID(CBI->getIndirectDest(i)));
3056 
3057     Vals.push_back(VE.getTypeID(FTy));
3058     pushValueAndType(Callee, InstID, Vals);
3059 
3060     // Emit value #'s for the fixed parameters.
3061     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
3062       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
3063 
3064     // Emit type/value pairs for varargs params.
3065     if (FTy->isVarArg()) {
3066       for (unsigned i = FTy->getNumParams(), e = CBI->arg_size(); i != e; ++i)
3067         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
3068     }
3069     break;
3070   }
3071   case Instruction::Unreachable:
3072     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
3073     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
3074     break;
3075 
3076   case Instruction::PHI: {
3077     const PHINode &PN = cast<PHINode>(I);
3078     Code = bitc::FUNC_CODE_INST_PHI;
3079     // With the newer instruction encoding, forward references could give
3080     // negative valued IDs.  This is most common for PHIs, so we use
3081     // signed VBRs.
3082     SmallVector<uint64_t, 128> Vals64;
3083     Vals64.push_back(VE.getTypeID(PN.getType()));
3084     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
3085       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64);
3086       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
3087     }
3088 
3089     uint64_t Flags = getOptimizationFlags(&I);
3090     if (Flags != 0)
3091       Vals64.push_back(Flags);
3092 
3093     // Emit a Vals64 vector and exit.
3094     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
3095     Vals64.clear();
3096     return;
3097   }
3098 
3099   case Instruction::LandingPad: {
3100     const LandingPadInst &LP = cast<LandingPadInst>(I);
3101     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
3102     Vals.push_back(VE.getTypeID(LP.getType()));
3103     Vals.push_back(LP.isCleanup());
3104     Vals.push_back(LP.getNumClauses());
3105     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
3106       if (LP.isCatch(I))
3107         Vals.push_back(LandingPadInst::Catch);
3108       else
3109         Vals.push_back(LandingPadInst::Filter);
3110       pushValueAndType(LP.getClause(I), InstID, Vals);
3111     }
3112     break;
3113   }
3114 
3115   case Instruction::Alloca: {
3116     Code = bitc::FUNC_CODE_INST_ALLOCA;
3117     const AllocaInst &AI = cast<AllocaInst>(I);
3118     Vals.push_back(VE.getTypeID(AI.getAllocatedType()));
3119     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
3120     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
3121     using APV = AllocaPackedValues;
3122     unsigned Record = 0;
3123     unsigned EncodedAlign = getEncodedAlign(AI.getAlign());
3124     Bitfield::set<APV::AlignLower>(
3125         Record, EncodedAlign & ((1 << APV::AlignLower::Bits) - 1));
3126     Bitfield::set<APV::AlignUpper>(Record,
3127                                    EncodedAlign >> APV::AlignLower::Bits);
3128     Bitfield::set<APV::UsedWithInAlloca>(Record, AI.isUsedWithInAlloca());
3129     Bitfield::set<APV::ExplicitType>(Record, true);
3130     Bitfield::set<APV::SwiftError>(Record, AI.isSwiftError());
3131     Vals.push_back(Record);
3132 
3133     unsigned AS = AI.getAddressSpace();
3134     if (AS != M.getDataLayout().getAllocaAddrSpace())
3135       Vals.push_back(AS);
3136     break;
3137   }
3138 
3139   case Instruction::Load:
3140     if (cast<LoadInst>(I).isAtomic()) {
3141       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
3142       pushValueAndType(I.getOperand(0), InstID, Vals);
3143     } else {
3144       Code = bitc::FUNC_CODE_INST_LOAD;
3145       if (!pushValueAndType(I.getOperand(0), InstID, Vals)) // ptr
3146         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
3147     }
3148     Vals.push_back(VE.getTypeID(I.getType()));
3149     Vals.push_back(getEncodedAlign(cast<LoadInst>(I).getAlign()));
3150     Vals.push_back(cast<LoadInst>(I).isVolatile());
3151     if (cast<LoadInst>(I).isAtomic()) {
3152       Vals.push_back(getEncodedOrdering(cast<LoadInst>(I).getOrdering()));
3153       Vals.push_back(getEncodedSyncScopeID(cast<LoadInst>(I).getSyncScopeID()));
3154     }
3155     break;
3156   case Instruction::Store:
3157     if (cast<StoreInst>(I).isAtomic())
3158       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
3159     else
3160       Code = bitc::FUNC_CODE_INST_STORE;
3161     pushValueAndType(I.getOperand(1), InstID, Vals); // ptrty + ptr
3162     pushValueAndType(I.getOperand(0), InstID, Vals); // valty + val
3163     Vals.push_back(getEncodedAlign(cast<StoreInst>(I).getAlign()));
3164     Vals.push_back(cast<StoreInst>(I).isVolatile());
3165     if (cast<StoreInst>(I).isAtomic()) {
3166       Vals.push_back(getEncodedOrdering(cast<StoreInst>(I).getOrdering()));
3167       Vals.push_back(
3168           getEncodedSyncScopeID(cast<StoreInst>(I).getSyncScopeID()));
3169     }
3170     break;
3171   case Instruction::AtomicCmpXchg:
3172     Code = bitc::FUNC_CODE_INST_CMPXCHG;
3173     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
3174     pushValueAndType(I.getOperand(1), InstID, Vals); // cmp.
3175     pushValue(I.getOperand(2), InstID, Vals);        // newval.
3176     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
3177     Vals.push_back(
3178         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
3179     Vals.push_back(
3180         getEncodedSyncScopeID(cast<AtomicCmpXchgInst>(I).getSyncScopeID()));
3181     Vals.push_back(
3182         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
3183     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
3184     Vals.push_back(getEncodedAlign(cast<AtomicCmpXchgInst>(I).getAlign()));
3185     break;
3186   case Instruction::AtomicRMW:
3187     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
3188     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
3189     pushValueAndType(I.getOperand(1), InstID, Vals); // valty + val
3190     Vals.push_back(
3191         getEncodedRMWOperation(cast<AtomicRMWInst>(I).getOperation()));
3192     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
3193     Vals.push_back(getEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
3194     Vals.push_back(
3195         getEncodedSyncScopeID(cast<AtomicRMWInst>(I).getSyncScopeID()));
3196     Vals.push_back(getEncodedAlign(cast<AtomicRMWInst>(I).getAlign()));
3197     break;
3198   case Instruction::Fence:
3199     Code = bitc::FUNC_CODE_INST_FENCE;
3200     Vals.push_back(getEncodedOrdering(cast<FenceInst>(I).getOrdering()));
3201     Vals.push_back(getEncodedSyncScopeID(cast<FenceInst>(I).getSyncScopeID()));
3202     break;
3203   case Instruction::Call: {
3204     const CallInst &CI = cast<CallInst>(I);
3205     FunctionType *FTy = CI.getFunctionType();
3206 
3207     if (CI.hasOperandBundles())
3208       writeOperandBundles(CI, InstID);
3209 
3210     Code = bitc::FUNC_CODE_INST_CALL;
3211 
3212     Vals.push_back(VE.getAttributeListID(CI.getAttributes()));
3213 
3214     unsigned Flags = getOptimizationFlags(&I);
3215     Vals.push_back(CI.getCallingConv() << bitc::CALL_CCONV |
3216                    unsigned(CI.isTailCall()) << bitc::CALL_TAIL |
3217                    unsigned(CI.isMustTailCall()) << bitc::CALL_MUSTTAIL |
3218                    1 << bitc::CALL_EXPLICIT_TYPE |
3219                    unsigned(CI.isNoTailCall()) << bitc::CALL_NOTAIL |
3220                    unsigned(Flags != 0) << bitc::CALL_FMF);
3221     if (Flags != 0)
3222       Vals.push_back(Flags);
3223 
3224     Vals.push_back(VE.getTypeID(FTy));
3225     pushValueAndType(CI.getCalledOperand(), InstID, Vals); // Callee
3226 
3227     // Emit value #'s for the fixed parameters.
3228     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
3229       // Check for labels (can happen with asm labels).
3230       if (FTy->getParamType(i)->isLabelTy())
3231         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
3232       else
3233         pushValue(CI.getArgOperand(i), InstID, Vals); // fixed param.
3234     }
3235 
3236     // Emit type/value pairs for varargs params.
3237     if (FTy->isVarArg()) {
3238       for (unsigned i = FTy->getNumParams(), e = CI.arg_size(); i != e; ++i)
3239         pushValueAndType(CI.getArgOperand(i), InstID, Vals); // varargs
3240     }
3241     break;
3242   }
3243   case Instruction::VAArg:
3244     Code = bitc::FUNC_CODE_INST_VAARG;
3245     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
3246     pushValue(I.getOperand(0), InstID, Vals);                   // valist.
3247     Vals.push_back(VE.getTypeID(I.getType())); // restype.
3248     break;
3249   case Instruction::Freeze:
3250     Code = bitc::FUNC_CODE_INST_FREEZE;
3251     pushValueAndType(I.getOperand(0), InstID, Vals);
3252     break;
3253   }
3254 
3255   Stream.EmitRecord(Code, Vals, AbbrevToUse);
3256   Vals.clear();
3257 }
3258 
3259 /// Write a GlobalValue VST to the module. The purpose of this data structure is
3260 /// to allow clients to efficiently find the function body.
3261 void ModuleBitcodeWriter::writeGlobalValueSymbolTable(
3262   DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3263   // Get the offset of the VST we are writing, and backpatch it into
3264   // the VST forward declaration record.
3265   uint64_t VSTOffset = Stream.GetCurrentBitNo();
3266   // The BitcodeStartBit was the stream offset of the identification block.
3267   VSTOffset -= bitcodeStartBit();
3268   assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
3269   // Note that we add 1 here because the offset is relative to one word
3270   // before the start of the identification block, which was historically
3271   // always the start of the regular bitcode header.
3272   Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32 + 1);
3273 
3274   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3275 
3276   auto Abbv = std::make_shared<BitCodeAbbrev>();
3277   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
3278   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
3279   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
3280   unsigned FnEntryAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3281 
3282   for (const Function &F : M) {
3283     uint64_t Record[2];
3284 
3285     if (F.isDeclaration())
3286       continue;
3287 
3288     Record[0] = VE.getValueID(&F);
3289 
3290     // Save the word offset of the function (from the start of the
3291     // actual bitcode written to the stream).
3292     uint64_t BitcodeIndex = FunctionToBitcodeIndex[&F] - bitcodeStartBit();
3293     assert((BitcodeIndex & 31) == 0 && "function block not 32-bit aligned");
3294     // Note that we add 1 here because the offset is relative to one word
3295     // before the start of the identification block, which was historically
3296     // always the start of the regular bitcode header.
3297     Record[1] = BitcodeIndex / 32 + 1;
3298 
3299     Stream.EmitRecord(bitc::VST_CODE_FNENTRY, Record, FnEntryAbbrev);
3300   }
3301 
3302   Stream.ExitBlock();
3303 }
3304 
3305 /// Emit names for arguments, instructions and basic blocks in a function.
3306 void ModuleBitcodeWriter::writeFunctionLevelValueSymbolTable(
3307     const ValueSymbolTable &VST) {
3308   if (VST.empty())
3309     return;
3310 
3311   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3312 
3313   // FIXME: Set up the abbrev, we know how many values there are!
3314   // FIXME: We know if the type names can use 7-bit ascii.
3315   SmallVector<uint64_t, 64> NameVals;
3316 
3317   for (const ValueName &Name : VST) {
3318     // Figure out the encoding to use for the name.
3319     StringEncoding Bits = getStringEncoding(Name.getKey());
3320 
3321     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
3322     NameVals.push_back(VE.getValueID(Name.getValue()));
3323 
3324     // VST_CODE_ENTRY:   [valueid, namechar x N]
3325     // VST_CODE_BBENTRY: [bbid, namechar x N]
3326     unsigned Code;
3327     if (isa<BasicBlock>(Name.getValue())) {
3328       Code = bitc::VST_CODE_BBENTRY;
3329       if (Bits == SE_Char6)
3330         AbbrevToUse = VST_BBENTRY_6_ABBREV;
3331     } else {
3332       Code = bitc::VST_CODE_ENTRY;
3333       if (Bits == SE_Char6)
3334         AbbrevToUse = VST_ENTRY_6_ABBREV;
3335       else if (Bits == SE_Fixed7)
3336         AbbrevToUse = VST_ENTRY_7_ABBREV;
3337     }
3338 
3339     for (const auto P : Name.getKey())
3340       NameVals.push_back((unsigned char)P);
3341 
3342     // Emit the finished record.
3343     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
3344     NameVals.clear();
3345   }
3346 
3347   Stream.ExitBlock();
3348 }
3349 
3350 void ModuleBitcodeWriter::writeUseList(UseListOrder &&Order) {
3351   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
3352   unsigned Code;
3353   if (isa<BasicBlock>(Order.V))
3354     Code = bitc::USELIST_CODE_BB;
3355   else
3356     Code = bitc::USELIST_CODE_DEFAULT;
3357 
3358   SmallVector<uint64_t, 64> Record(Order.Shuffle.begin(), Order.Shuffle.end());
3359   Record.push_back(VE.getValueID(Order.V));
3360   Stream.EmitRecord(Code, Record);
3361 }
3362 
3363 void ModuleBitcodeWriter::writeUseListBlock(const Function *F) {
3364   assert(VE.shouldPreserveUseListOrder() &&
3365          "Expected to be preserving use-list order");
3366 
3367   auto hasMore = [&]() {
3368     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
3369   };
3370   if (!hasMore())
3371     // Nothing to do.
3372     return;
3373 
3374   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
3375   while (hasMore()) {
3376     writeUseList(std::move(VE.UseListOrders.back()));
3377     VE.UseListOrders.pop_back();
3378   }
3379   Stream.ExitBlock();
3380 }
3381 
3382 /// Emit a function body to the module stream.
3383 void ModuleBitcodeWriter::writeFunction(
3384     const Function &F,
3385     DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3386   // Save the bitcode index of the start of this function block for recording
3387   // in the VST.
3388   FunctionToBitcodeIndex[&F] = Stream.GetCurrentBitNo();
3389 
3390   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
3391   VE.incorporateFunction(F);
3392 
3393   SmallVector<unsigned, 64> Vals;
3394 
3395   // Emit the number of basic blocks, so the reader can create them ahead of
3396   // time.
3397   Vals.push_back(VE.getBasicBlocks().size());
3398   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
3399   Vals.clear();
3400 
3401   // If there are function-local constants, emit them now.
3402   unsigned CstStart, CstEnd;
3403   VE.getFunctionConstantRange(CstStart, CstEnd);
3404   writeConstants(CstStart, CstEnd, false);
3405 
3406   // If there is function-local metadata, emit it now.
3407   writeFunctionMetadata(F);
3408 
3409   // Keep a running idea of what the instruction ID is.
3410   unsigned InstID = CstEnd;
3411 
3412   bool NeedsMetadataAttachment = F.hasMetadata();
3413 
3414   DILocation *LastDL = nullptr;
3415   SmallSetVector<Function *, 4> BlockAddressUsers;
3416 
3417   // Finally, emit all the instructions, in order.
3418   for (const BasicBlock &BB : F) {
3419     for (const Instruction &I : BB) {
3420       writeInstruction(I, InstID, Vals);
3421 
3422       if (!I.getType()->isVoidTy())
3423         ++InstID;
3424 
3425       // If the instruction has metadata, write a metadata attachment later.
3426       NeedsMetadataAttachment |= I.hasMetadataOtherThanDebugLoc();
3427 
3428       // If the instruction has a debug location, emit it.
3429       DILocation *DL = I.getDebugLoc();
3430       if (!DL)
3431         continue;
3432 
3433       if (DL == LastDL) {
3434         // Just repeat the same debug loc as last time.
3435         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
3436         continue;
3437       }
3438 
3439       Vals.push_back(DL->getLine());
3440       Vals.push_back(DL->getColumn());
3441       Vals.push_back(VE.getMetadataOrNullID(DL->getScope()));
3442       Vals.push_back(VE.getMetadataOrNullID(DL->getInlinedAt()));
3443       Vals.push_back(DL->isImplicitCode());
3444       Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
3445       Vals.clear();
3446 
3447       LastDL = DL;
3448     }
3449 
3450     if (BlockAddress *BA = BlockAddress::lookup(&BB)) {
3451       SmallVector<Value *> Worklist{BA};
3452       SmallPtrSet<Value *, 8> Visited{BA};
3453       while (!Worklist.empty()) {
3454         Value *V = Worklist.pop_back_val();
3455         for (User *U : V->users()) {
3456           if (auto *I = dyn_cast<Instruction>(U)) {
3457             Function *P = I->getFunction();
3458             if (P != &F)
3459               BlockAddressUsers.insert(P);
3460           } else if (isa<Constant>(U) && !isa<GlobalValue>(U) &&
3461                      Visited.insert(U).second)
3462             Worklist.push_back(U);
3463         }
3464       }
3465     }
3466   }
3467 
3468   if (!BlockAddressUsers.empty()) {
3469     Vals.resize(BlockAddressUsers.size());
3470     for (auto I : llvm::enumerate(BlockAddressUsers))
3471       Vals[I.index()] = VE.getValueID(I.value());
3472     Stream.EmitRecord(bitc::FUNC_CODE_BLOCKADDR_USERS, Vals);
3473     Vals.clear();
3474   }
3475 
3476   // Emit names for all the instructions etc.
3477   if (auto *Symtab = F.getValueSymbolTable())
3478     writeFunctionLevelValueSymbolTable(*Symtab);
3479 
3480   if (NeedsMetadataAttachment)
3481     writeFunctionMetadataAttachment(F);
3482   if (VE.shouldPreserveUseListOrder())
3483     writeUseListBlock(&F);
3484   VE.purgeFunction();
3485   Stream.ExitBlock();
3486 }
3487 
3488 // Emit blockinfo, which defines the standard abbreviations etc.
3489 void ModuleBitcodeWriter::writeBlockInfo() {
3490   // We only want to emit block info records for blocks that have multiple
3491   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
3492   // Other blocks can define their abbrevs inline.
3493   Stream.EnterBlockInfoBlock();
3494 
3495   { // 8-bit fixed-width VST_CODE_ENTRY/VST_CODE_BBENTRY strings.
3496     auto Abbv = std::make_shared<BitCodeAbbrev>();
3497     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
3498     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3499     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3500     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3501     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3502         VST_ENTRY_8_ABBREV)
3503       llvm_unreachable("Unexpected abbrev ordering!");
3504   }
3505 
3506   { // 7-bit fixed width VST_CODE_ENTRY strings.
3507     auto Abbv = std::make_shared<BitCodeAbbrev>();
3508     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3509     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3510     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3511     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3512     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3513         VST_ENTRY_7_ABBREV)
3514       llvm_unreachable("Unexpected abbrev ordering!");
3515   }
3516   { // 6-bit char6 VST_CODE_ENTRY strings.
3517     auto Abbv = std::make_shared<BitCodeAbbrev>();
3518     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3519     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3520     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3521     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3522     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3523         VST_ENTRY_6_ABBREV)
3524       llvm_unreachable("Unexpected abbrev ordering!");
3525   }
3526   { // 6-bit char6 VST_CODE_BBENTRY strings.
3527     auto Abbv = std::make_shared<BitCodeAbbrev>();
3528     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
3529     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3530     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3531     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3532     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3533         VST_BBENTRY_6_ABBREV)
3534       llvm_unreachable("Unexpected abbrev ordering!");
3535   }
3536 
3537   { // SETTYPE abbrev for CONSTANTS_BLOCK.
3538     auto Abbv = std::make_shared<BitCodeAbbrev>();
3539     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
3540     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
3541                               VE.computeBitsRequiredForTypeIndicies()));
3542     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3543         CONSTANTS_SETTYPE_ABBREV)
3544       llvm_unreachable("Unexpected abbrev ordering!");
3545   }
3546 
3547   { // INTEGER abbrev for CONSTANTS_BLOCK.
3548     auto Abbv = std::make_shared<BitCodeAbbrev>();
3549     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
3550     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3551     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3552         CONSTANTS_INTEGER_ABBREV)
3553       llvm_unreachable("Unexpected abbrev ordering!");
3554   }
3555 
3556   { // CE_CAST abbrev for CONSTANTS_BLOCK.
3557     auto Abbv = std::make_shared<BitCodeAbbrev>();
3558     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
3559     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
3560     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
3561                               VE.computeBitsRequiredForTypeIndicies()));
3562     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
3563 
3564     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3565         CONSTANTS_CE_CAST_Abbrev)
3566       llvm_unreachable("Unexpected abbrev ordering!");
3567   }
3568   { // NULL abbrev for CONSTANTS_BLOCK.
3569     auto Abbv = std::make_shared<BitCodeAbbrev>();
3570     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
3571     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3572         CONSTANTS_NULL_Abbrev)
3573       llvm_unreachable("Unexpected abbrev ordering!");
3574   }
3575 
3576   // FIXME: This should only use space for first class types!
3577 
3578   { // INST_LOAD abbrev for FUNCTION_BLOCK.
3579     auto Abbv = std::make_shared<BitCodeAbbrev>();
3580     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
3581     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
3582     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
3583                               VE.computeBitsRequiredForTypeIndicies()));
3584     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
3585     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
3586     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3587         FUNCTION_INST_LOAD_ABBREV)
3588       llvm_unreachable("Unexpected abbrev ordering!");
3589   }
3590   { // INST_UNOP abbrev for FUNCTION_BLOCK.
3591     auto Abbv = std::make_shared<BitCodeAbbrev>();
3592     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3593     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3594     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3595     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3596         FUNCTION_INST_UNOP_ABBREV)
3597       llvm_unreachable("Unexpected abbrev ordering!");
3598   }
3599   { // INST_UNOP_FLAGS abbrev for FUNCTION_BLOCK.
3600     auto Abbv = std::make_shared<BitCodeAbbrev>();
3601     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3602     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3603     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3604     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3605     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3606         FUNCTION_INST_UNOP_FLAGS_ABBREV)
3607       llvm_unreachable("Unexpected abbrev ordering!");
3608   }
3609   { // INST_BINOP abbrev for FUNCTION_BLOCK.
3610     auto Abbv = std::make_shared<BitCodeAbbrev>();
3611     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3612     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3613     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3614     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3615     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3616         FUNCTION_INST_BINOP_ABBREV)
3617       llvm_unreachable("Unexpected abbrev ordering!");
3618   }
3619   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
3620     auto Abbv = std::make_shared<BitCodeAbbrev>();
3621     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3622     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3623     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3624     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3625     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3626     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3627         FUNCTION_INST_BINOP_FLAGS_ABBREV)
3628       llvm_unreachable("Unexpected abbrev ordering!");
3629   }
3630   { // INST_CAST abbrev for FUNCTION_BLOCK.
3631     auto Abbv = std::make_shared<BitCodeAbbrev>();
3632     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
3633     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
3634     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
3635                               VE.computeBitsRequiredForTypeIndicies()));
3636     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
3637     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3638         FUNCTION_INST_CAST_ABBREV)
3639       llvm_unreachable("Unexpected abbrev ordering!");
3640   }
3641 
3642   { // INST_RET abbrev for FUNCTION_BLOCK.
3643     auto Abbv = std::make_shared<BitCodeAbbrev>();
3644     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3645     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3646         FUNCTION_INST_RET_VOID_ABBREV)
3647       llvm_unreachable("Unexpected abbrev ordering!");
3648   }
3649   { // INST_RET abbrev for FUNCTION_BLOCK.
3650     auto Abbv = std::make_shared<BitCodeAbbrev>();
3651     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3652     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
3653     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3654         FUNCTION_INST_RET_VAL_ABBREV)
3655       llvm_unreachable("Unexpected abbrev ordering!");
3656   }
3657   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
3658     auto Abbv = std::make_shared<BitCodeAbbrev>();
3659     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
3660     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3661         FUNCTION_INST_UNREACHABLE_ABBREV)
3662       llvm_unreachable("Unexpected abbrev ordering!");
3663   }
3664   {
3665     auto Abbv = std::make_shared<BitCodeAbbrev>();
3666     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_GEP));
3667     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
3668     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, // dest ty
3669                               Log2_32_Ceil(VE.getTypes().size() + 1)));
3670     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3671     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
3672     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3673         FUNCTION_INST_GEP_ABBREV)
3674       llvm_unreachable("Unexpected abbrev ordering!");
3675   }
3676 
3677   Stream.ExitBlock();
3678 }
3679 
3680 /// Write the module path strings, currently only used when generating
3681 /// a combined index file.
3682 void IndexBitcodeWriter::writeModStrings() {
3683   Stream.EnterSubblock(bitc::MODULE_STRTAB_BLOCK_ID, 3);
3684 
3685   // TODO: See which abbrev sizes we actually need to emit
3686 
3687   // 8-bit fixed-width MST_ENTRY strings.
3688   auto Abbv = std::make_shared<BitCodeAbbrev>();
3689   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3690   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3691   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3692   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3693   unsigned Abbrev8Bit = Stream.EmitAbbrev(std::move(Abbv));
3694 
3695   // 7-bit fixed width MST_ENTRY strings.
3696   Abbv = std::make_shared<BitCodeAbbrev>();
3697   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3698   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3699   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3700   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3701   unsigned Abbrev7Bit = Stream.EmitAbbrev(std::move(Abbv));
3702 
3703   // 6-bit char6 MST_ENTRY strings.
3704   Abbv = std::make_shared<BitCodeAbbrev>();
3705   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3706   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3707   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3708   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3709   unsigned Abbrev6Bit = Stream.EmitAbbrev(std::move(Abbv));
3710 
3711   // Module Hash, 160 bits SHA1. Optionally, emitted after each MST_CODE_ENTRY.
3712   Abbv = std::make_shared<BitCodeAbbrev>();
3713   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_HASH));
3714   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3715   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3716   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3717   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3718   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3719   unsigned AbbrevHash = Stream.EmitAbbrev(std::move(Abbv));
3720 
3721   SmallVector<unsigned, 64> Vals;
3722   forEachModule(
3723       [&](const StringMapEntry<std::pair<uint64_t, ModuleHash>> &MPSE) {
3724         StringRef Key = MPSE.getKey();
3725         const auto &Value = MPSE.getValue();
3726         StringEncoding Bits = getStringEncoding(Key);
3727         unsigned AbbrevToUse = Abbrev8Bit;
3728         if (Bits == SE_Char6)
3729           AbbrevToUse = Abbrev6Bit;
3730         else if (Bits == SE_Fixed7)
3731           AbbrevToUse = Abbrev7Bit;
3732 
3733         Vals.push_back(Value.first);
3734         Vals.append(Key.begin(), Key.end());
3735 
3736         // Emit the finished record.
3737         Stream.EmitRecord(bitc::MST_CODE_ENTRY, Vals, AbbrevToUse);
3738 
3739         // Emit an optional hash for the module now
3740         const auto &Hash = Value.second;
3741         if (llvm::any_of(Hash, [](uint32_t H) { return H; })) {
3742           Vals.assign(Hash.begin(), Hash.end());
3743           // Emit the hash record.
3744           Stream.EmitRecord(bitc::MST_CODE_HASH, Vals, AbbrevHash);
3745         }
3746 
3747         Vals.clear();
3748       });
3749   Stream.ExitBlock();
3750 }
3751 
3752 /// Write the function type metadata related records that need to appear before
3753 /// a function summary entry (whether per-module or combined).
3754 template <typename Fn>
3755 static void writeFunctionTypeMetadataRecords(BitstreamWriter &Stream,
3756                                              FunctionSummary *FS,
3757                                              Fn GetValueID) {
3758   if (!FS->type_tests().empty())
3759     Stream.EmitRecord(bitc::FS_TYPE_TESTS, FS->type_tests());
3760 
3761   SmallVector<uint64_t, 64> Record;
3762 
3763   auto WriteVFuncIdVec = [&](uint64_t Ty,
3764                              ArrayRef<FunctionSummary::VFuncId> VFs) {
3765     if (VFs.empty())
3766       return;
3767     Record.clear();
3768     for (auto &VF : VFs) {
3769       Record.push_back(VF.GUID);
3770       Record.push_back(VF.Offset);
3771     }
3772     Stream.EmitRecord(Ty, Record);
3773   };
3774 
3775   WriteVFuncIdVec(bitc::FS_TYPE_TEST_ASSUME_VCALLS,
3776                   FS->type_test_assume_vcalls());
3777   WriteVFuncIdVec(bitc::FS_TYPE_CHECKED_LOAD_VCALLS,
3778                   FS->type_checked_load_vcalls());
3779 
3780   auto WriteConstVCallVec = [&](uint64_t Ty,
3781                                 ArrayRef<FunctionSummary::ConstVCall> VCs) {
3782     for (auto &VC : VCs) {
3783       Record.clear();
3784       Record.push_back(VC.VFunc.GUID);
3785       Record.push_back(VC.VFunc.Offset);
3786       llvm::append_range(Record, VC.Args);
3787       Stream.EmitRecord(Ty, Record);
3788     }
3789   };
3790 
3791   WriteConstVCallVec(bitc::FS_TYPE_TEST_ASSUME_CONST_VCALL,
3792                      FS->type_test_assume_const_vcalls());
3793   WriteConstVCallVec(bitc::FS_TYPE_CHECKED_LOAD_CONST_VCALL,
3794                      FS->type_checked_load_const_vcalls());
3795 
3796   auto WriteRange = [&](ConstantRange Range) {
3797     Range = Range.sextOrTrunc(FunctionSummary::ParamAccess::RangeWidth);
3798     assert(Range.getLower().getNumWords() == 1);
3799     assert(Range.getUpper().getNumWords() == 1);
3800     emitSignedInt64(Record, *Range.getLower().getRawData());
3801     emitSignedInt64(Record, *Range.getUpper().getRawData());
3802   };
3803 
3804   if (!FS->paramAccesses().empty()) {
3805     Record.clear();
3806     for (auto &Arg : FS->paramAccesses()) {
3807       size_t UndoSize = Record.size();
3808       Record.push_back(Arg.ParamNo);
3809       WriteRange(Arg.Use);
3810       Record.push_back(Arg.Calls.size());
3811       for (auto &Call : Arg.Calls) {
3812         Record.push_back(Call.ParamNo);
3813         std::optional<unsigned> ValueID = GetValueID(Call.Callee);
3814         if (!ValueID) {
3815           // If ValueID is unknown we can't drop just this call, we must drop
3816           // entire parameter.
3817           Record.resize(UndoSize);
3818           break;
3819         }
3820         Record.push_back(*ValueID);
3821         WriteRange(Call.Offsets);
3822       }
3823     }
3824     if (!Record.empty())
3825       Stream.EmitRecord(bitc::FS_PARAM_ACCESS, Record);
3826   }
3827 }
3828 
3829 /// Collect type IDs from type tests used by function.
3830 static void
3831 getReferencedTypeIds(FunctionSummary *FS,
3832                      std::set<GlobalValue::GUID> &ReferencedTypeIds) {
3833   if (!FS->type_tests().empty())
3834     for (auto &TT : FS->type_tests())
3835       ReferencedTypeIds.insert(TT);
3836 
3837   auto GetReferencedTypesFromVFuncIdVec =
3838       [&](ArrayRef<FunctionSummary::VFuncId> VFs) {
3839         for (auto &VF : VFs)
3840           ReferencedTypeIds.insert(VF.GUID);
3841       };
3842 
3843   GetReferencedTypesFromVFuncIdVec(FS->type_test_assume_vcalls());
3844   GetReferencedTypesFromVFuncIdVec(FS->type_checked_load_vcalls());
3845 
3846   auto GetReferencedTypesFromConstVCallVec =
3847       [&](ArrayRef<FunctionSummary::ConstVCall> VCs) {
3848         for (auto &VC : VCs)
3849           ReferencedTypeIds.insert(VC.VFunc.GUID);
3850       };
3851 
3852   GetReferencedTypesFromConstVCallVec(FS->type_test_assume_const_vcalls());
3853   GetReferencedTypesFromConstVCallVec(FS->type_checked_load_const_vcalls());
3854 }
3855 
3856 static void writeWholeProgramDevirtResolutionByArg(
3857     SmallVector<uint64_t, 64> &NameVals, const std::vector<uint64_t> &args,
3858     const WholeProgramDevirtResolution::ByArg &ByArg) {
3859   NameVals.push_back(args.size());
3860   llvm::append_range(NameVals, args);
3861 
3862   NameVals.push_back(ByArg.TheKind);
3863   NameVals.push_back(ByArg.Info);
3864   NameVals.push_back(ByArg.Byte);
3865   NameVals.push_back(ByArg.Bit);
3866 }
3867 
3868 static void writeWholeProgramDevirtResolution(
3869     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3870     uint64_t Id, const WholeProgramDevirtResolution &Wpd) {
3871   NameVals.push_back(Id);
3872 
3873   NameVals.push_back(Wpd.TheKind);
3874   NameVals.push_back(StrtabBuilder.add(Wpd.SingleImplName));
3875   NameVals.push_back(Wpd.SingleImplName.size());
3876 
3877   NameVals.push_back(Wpd.ResByArg.size());
3878   for (auto &A : Wpd.ResByArg)
3879     writeWholeProgramDevirtResolutionByArg(NameVals, A.first, A.second);
3880 }
3881 
3882 static void writeTypeIdSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
3883                                      StringTableBuilder &StrtabBuilder,
3884                                      const std::string &Id,
3885                                      const TypeIdSummary &Summary) {
3886   NameVals.push_back(StrtabBuilder.add(Id));
3887   NameVals.push_back(Id.size());
3888 
3889   NameVals.push_back(Summary.TTRes.TheKind);
3890   NameVals.push_back(Summary.TTRes.SizeM1BitWidth);
3891   NameVals.push_back(Summary.TTRes.AlignLog2);
3892   NameVals.push_back(Summary.TTRes.SizeM1);
3893   NameVals.push_back(Summary.TTRes.BitMask);
3894   NameVals.push_back(Summary.TTRes.InlineBits);
3895 
3896   for (auto &W : Summary.WPDRes)
3897     writeWholeProgramDevirtResolution(NameVals, StrtabBuilder, W.first,
3898                                       W.second);
3899 }
3900 
3901 static void writeTypeIdCompatibleVtableSummaryRecord(
3902     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3903     const std::string &Id, const TypeIdCompatibleVtableInfo &Summary,
3904     ValueEnumerator &VE) {
3905   NameVals.push_back(StrtabBuilder.add(Id));
3906   NameVals.push_back(Id.size());
3907 
3908   for (auto &P : Summary) {
3909     NameVals.push_back(P.AddressPointOffset);
3910     NameVals.push_back(VE.getValueID(P.VTableVI.getValue()));
3911   }
3912 }
3913 
3914 static void writeFunctionHeapProfileRecords(
3915     BitstreamWriter &Stream, FunctionSummary *FS, unsigned CallsiteAbbrev,
3916     unsigned AllocAbbrev, bool PerModule,
3917     std::function<unsigned(const ValueInfo &VI)> GetValueID,
3918     std::function<unsigned(unsigned)> GetStackIndex) {
3919   SmallVector<uint64_t> Record;
3920 
3921   for (auto &CI : FS->callsites()) {
3922     Record.clear();
3923     // Per module callsite clones should always have a single entry of
3924     // value 0.
3925     assert(!PerModule || (CI.Clones.size() == 1 && CI.Clones[0] == 0));
3926     Record.push_back(GetValueID(CI.Callee));
3927     if (!PerModule) {
3928       Record.push_back(CI.StackIdIndices.size());
3929       Record.push_back(CI.Clones.size());
3930     }
3931     for (auto Id : CI.StackIdIndices)
3932       Record.push_back(GetStackIndex(Id));
3933     if (!PerModule) {
3934       for (auto V : CI.Clones)
3935         Record.push_back(V);
3936     }
3937     Stream.EmitRecord(PerModule ? bitc::FS_PERMODULE_CALLSITE_INFO
3938                                 : bitc::FS_COMBINED_CALLSITE_INFO,
3939                       Record, CallsiteAbbrev);
3940   }
3941 
3942   for (auto &AI : FS->allocs()) {
3943     Record.clear();
3944     // Per module alloc versions should always have a single entry of
3945     // value 0.
3946     assert(!PerModule || (AI.Versions.size() == 1 && AI.Versions[0] == 0));
3947     if (!PerModule) {
3948       Record.push_back(AI.MIBs.size());
3949       Record.push_back(AI.Versions.size());
3950     }
3951     for (auto &MIB : AI.MIBs) {
3952       Record.push_back((uint8_t)MIB.AllocType);
3953       Record.push_back(MIB.StackIdIndices.size());
3954       for (auto Id : MIB.StackIdIndices)
3955         Record.push_back(GetStackIndex(Id));
3956     }
3957     if (!PerModule) {
3958       for (auto V : AI.Versions)
3959         Record.push_back(V);
3960     }
3961     Stream.EmitRecord(PerModule ? bitc::FS_PERMODULE_ALLOC_INFO
3962                                 : bitc::FS_COMBINED_ALLOC_INFO,
3963                       Record, AllocAbbrev);
3964   }
3965 }
3966 
3967 // Helper to emit a single function summary record.
3968 void ModuleBitcodeWriterBase::writePerModuleFunctionSummaryRecord(
3969     SmallVector<uint64_t, 64> &NameVals, GlobalValueSummary *Summary,
3970     unsigned ValueID, unsigned FSCallsAbbrev, unsigned FSCallsProfileAbbrev,
3971     unsigned CallsiteAbbrev, unsigned AllocAbbrev, const Function &F) {
3972   NameVals.push_back(ValueID);
3973 
3974   FunctionSummary *FS = cast<FunctionSummary>(Summary);
3975 
3976   writeFunctionTypeMetadataRecords(
3977       Stream, FS, [&](const ValueInfo &VI) -> std::optional<unsigned> {
3978         return {VE.getValueID(VI.getValue())};
3979       });
3980 
3981   writeFunctionHeapProfileRecords(
3982       Stream, FS, CallsiteAbbrev, AllocAbbrev,
3983       /*PerModule*/ true,
3984       /*GetValueId*/ [&](const ValueInfo &VI) { return getValueId(VI); },
3985       /*GetStackIndex*/ [&](unsigned I) { return I; });
3986 
3987   auto SpecialRefCnts = FS->specialRefCounts();
3988   NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
3989   NameVals.push_back(FS->instCount());
3990   NameVals.push_back(getEncodedFFlags(FS->fflags()));
3991   NameVals.push_back(FS->refs().size());
3992   NameVals.push_back(SpecialRefCnts.first);  // rorefcnt
3993   NameVals.push_back(SpecialRefCnts.second); // worefcnt
3994 
3995   for (auto &RI : FS->refs())
3996     NameVals.push_back(VE.getValueID(RI.getValue()));
3997 
3998   bool HasProfileData =
3999       F.hasProfileData() || ForceSummaryEdgesCold != FunctionSummary::FSHT_None;
4000   for (auto &ECI : FS->calls()) {
4001     NameVals.push_back(getValueId(ECI.first));
4002     if (HasProfileData)
4003       NameVals.push_back(static_cast<uint8_t>(ECI.second.Hotness));
4004     else if (WriteRelBFToSummary)
4005       NameVals.push_back(ECI.second.RelBlockFreq);
4006   }
4007 
4008   unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
4009   unsigned Code =
4010       (HasProfileData ? bitc::FS_PERMODULE_PROFILE
4011                       : (WriteRelBFToSummary ? bitc::FS_PERMODULE_RELBF
4012                                              : bitc::FS_PERMODULE));
4013 
4014   // Emit the finished record.
4015   Stream.EmitRecord(Code, NameVals, FSAbbrev);
4016   NameVals.clear();
4017 }
4018 
4019 // Collect the global value references in the given variable's initializer,
4020 // and emit them in a summary record.
4021 void ModuleBitcodeWriterBase::writeModuleLevelReferences(
4022     const GlobalVariable &V, SmallVector<uint64_t, 64> &NameVals,
4023     unsigned FSModRefsAbbrev, unsigned FSModVTableRefsAbbrev) {
4024   auto VI = Index->getValueInfo(V.getGUID());
4025   if (!VI || VI.getSummaryList().empty()) {
4026     // Only declarations should not have a summary (a declaration might however
4027     // have a summary if the def was in module level asm).
4028     assert(V.isDeclaration());
4029     return;
4030   }
4031   auto *Summary = VI.getSummaryList()[0].get();
4032   NameVals.push_back(VE.getValueID(&V));
4033   GlobalVarSummary *VS = cast<GlobalVarSummary>(Summary);
4034   NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
4035   NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
4036 
4037   auto VTableFuncs = VS->vTableFuncs();
4038   if (!VTableFuncs.empty())
4039     NameVals.push_back(VS->refs().size());
4040 
4041   unsigned SizeBeforeRefs = NameVals.size();
4042   for (auto &RI : VS->refs())
4043     NameVals.push_back(VE.getValueID(RI.getValue()));
4044   // Sort the refs for determinism output, the vector returned by FS->refs() has
4045   // been initialized from a DenseSet.
4046   llvm::sort(drop_begin(NameVals, SizeBeforeRefs));
4047 
4048   if (VTableFuncs.empty())
4049     Stream.EmitRecord(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS, NameVals,
4050                       FSModRefsAbbrev);
4051   else {
4052     // VTableFuncs pairs should already be sorted by offset.
4053     for (auto &P : VTableFuncs) {
4054       NameVals.push_back(VE.getValueID(P.FuncVI.getValue()));
4055       NameVals.push_back(P.VTableOffset);
4056     }
4057 
4058     Stream.EmitRecord(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS, NameVals,
4059                       FSModVTableRefsAbbrev);
4060   }
4061   NameVals.clear();
4062 }
4063 
4064 /// Emit the per-module summary section alongside the rest of
4065 /// the module's bitcode.
4066 void ModuleBitcodeWriterBase::writePerModuleGlobalValueSummary() {
4067   // By default we compile with ThinLTO if the module has a summary, but the
4068   // client can request full LTO with a module flag.
4069   bool IsThinLTO = true;
4070   if (auto *MD =
4071           mdconst::extract_or_null<ConstantInt>(M.getModuleFlag("ThinLTO")))
4072     IsThinLTO = MD->getZExtValue();
4073   Stream.EnterSubblock(IsThinLTO ? bitc::GLOBALVAL_SUMMARY_BLOCK_ID
4074                                  : bitc::FULL_LTO_GLOBALVAL_SUMMARY_BLOCK_ID,
4075                        4);
4076 
4077   Stream.EmitRecord(
4078       bitc::FS_VERSION,
4079       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
4080 
4081   // Write the index flags.
4082   uint64_t Flags = 0;
4083   // Bits 1-3 are set only in the combined index, skip them.
4084   if (Index->enableSplitLTOUnit())
4085     Flags |= 0x8;
4086   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Flags});
4087 
4088   if (Index->begin() == Index->end()) {
4089     Stream.ExitBlock();
4090     return;
4091   }
4092 
4093   for (const auto &GVI : valueIds()) {
4094     Stream.EmitRecord(bitc::FS_VALUE_GUID,
4095                       ArrayRef<uint64_t>{GVI.second, GVI.first});
4096   }
4097 
4098   if (!Index->stackIds().empty()) {
4099     auto StackIdAbbv = std::make_shared<BitCodeAbbrev>();
4100     StackIdAbbv->Add(BitCodeAbbrevOp(bitc::FS_STACK_IDS));
4101     // numids x stackid
4102     StackIdAbbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4103     StackIdAbbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4104     unsigned StackIdAbbvId = Stream.EmitAbbrev(std::move(StackIdAbbv));
4105     Stream.EmitRecord(bitc::FS_STACK_IDS, Index->stackIds(), StackIdAbbvId);
4106   }
4107 
4108   // Abbrev for FS_PERMODULE_PROFILE.
4109   auto Abbv = std::make_shared<BitCodeAbbrev>();
4110   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_PROFILE));
4111   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4112   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4113   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4114   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4115   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4116   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4117   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4118   // numrefs x valueid, n x (valueid, hotness)
4119   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4120   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4121   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4122 
4123   // Abbrev for FS_PERMODULE or FS_PERMODULE_RELBF.
4124   Abbv = std::make_shared<BitCodeAbbrev>();
4125   if (WriteRelBFToSummary)
4126     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_RELBF));
4127   else
4128     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE));
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 [, rel_block_freq])
4137   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4138   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4139   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4140 
4141   // Abbrev for FS_PERMODULE_GLOBALVAR_INIT_REFS.
4142   Abbv = std::make_shared<BitCodeAbbrev>();
4143   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS));
4144   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
4145   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
4146   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));  // valueids
4147   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4148   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4149 
4150   // Abbrev for FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS.
4151   Abbv = std::make_shared<BitCodeAbbrev>();
4152   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS));
4153   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
4154   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
4155   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numrefs
4156   // numrefs x valueid, n x (valueid , offset)
4157   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4158   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4159   unsigned FSModVTableRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4160 
4161   // Abbrev for FS_ALIAS.
4162   Abbv = std::make_shared<BitCodeAbbrev>();
4163   Abbv->Add(BitCodeAbbrevOp(bitc::FS_ALIAS));
4164   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4165   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4166   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4167   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4168 
4169   // Abbrev for FS_TYPE_ID_METADATA
4170   Abbv = std::make_shared<BitCodeAbbrev>();
4171   Abbv->Add(BitCodeAbbrevOp(bitc::FS_TYPE_ID_METADATA));
4172   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid strtab index
4173   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid length
4174   // n x (valueid , offset)
4175   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4176   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4177   unsigned TypeIdCompatibleVtableAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4178 
4179   Abbv = std::make_shared<BitCodeAbbrev>();
4180   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_CALLSITE_INFO));
4181   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
4182   // n x stackidindex
4183   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4184   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4185   unsigned CallsiteAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4186 
4187   Abbv = std::make_shared<BitCodeAbbrev>();
4188   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_ALLOC_INFO));
4189   // n x (alloc type, numstackids, numstackids x stackidindex)
4190   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4191   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4192   unsigned AllocAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4193 
4194   SmallVector<uint64_t, 64> NameVals;
4195   // Iterate over the list of functions instead of the Index to
4196   // ensure the ordering is stable.
4197   for (const Function &F : M) {
4198     // Summary emission does not support anonymous functions, they have to
4199     // renamed using the anonymous function renaming pass.
4200     if (!F.hasName())
4201       report_fatal_error("Unexpected anonymous function when writing summary");
4202 
4203     ValueInfo VI = Index->getValueInfo(F.getGUID());
4204     if (!VI || VI.getSummaryList().empty()) {
4205       // Only declarations should not have a summary (a declaration might
4206       // however have a summary if the def was in module level asm).
4207       assert(F.isDeclaration());
4208       continue;
4209     }
4210     auto *Summary = VI.getSummaryList()[0].get();
4211     writePerModuleFunctionSummaryRecord(NameVals, Summary, VE.getValueID(&F),
4212                                         FSCallsAbbrev, FSCallsProfileAbbrev,
4213                                         CallsiteAbbrev, AllocAbbrev, F);
4214   }
4215 
4216   // Capture references from GlobalVariable initializers, which are outside
4217   // of a function scope.
4218   for (const GlobalVariable &G : M.globals())
4219     writeModuleLevelReferences(G, NameVals, FSModRefsAbbrev,
4220                                FSModVTableRefsAbbrev);
4221 
4222   for (const GlobalAlias &A : M.aliases()) {
4223     auto *Aliasee = A.getAliaseeObject();
4224     // Skip ifunc and nameless functions which don't have an entry in the
4225     // summary.
4226     if (!Aliasee->hasName() || isa<GlobalIFunc>(Aliasee))
4227       continue;
4228     auto AliasId = VE.getValueID(&A);
4229     auto AliaseeId = VE.getValueID(Aliasee);
4230     NameVals.push_back(AliasId);
4231     auto *Summary = Index->getGlobalValueSummary(A);
4232     AliasSummary *AS = cast<AliasSummary>(Summary);
4233     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
4234     NameVals.push_back(AliaseeId);
4235     Stream.EmitRecord(bitc::FS_ALIAS, NameVals, FSAliasAbbrev);
4236     NameVals.clear();
4237   }
4238 
4239   for (auto &S : Index->typeIdCompatibleVtableMap()) {
4240     writeTypeIdCompatibleVtableSummaryRecord(NameVals, StrtabBuilder, S.first,
4241                                              S.second, VE);
4242     Stream.EmitRecord(bitc::FS_TYPE_ID_METADATA, NameVals,
4243                       TypeIdCompatibleVtableAbbrev);
4244     NameVals.clear();
4245   }
4246 
4247   Stream.EmitRecord(bitc::FS_BLOCK_COUNT,
4248                     ArrayRef<uint64_t>{Index->getBlockCount()});
4249 
4250   Stream.ExitBlock();
4251 }
4252 
4253 /// Emit the combined summary section into the combined index file.
4254 void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
4255   Stream.EnterSubblock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID, 4);
4256   Stream.EmitRecord(
4257       bitc::FS_VERSION,
4258       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
4259 
4260   // Write the index flags.
4261   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Index.getFlags()});
4262 
4263   for (const auto &GVI : valueIds()) {
4264     Stream.EmitRecord(bitc::FS_VALUE_GUID,
4265                       ArrayRef<uint64_t>{GVI.second, GVI.first});
4266   }
4267 
4268   if (!StackIdIndices.empty()) {
4269     auto StackIdAbbv = std::make_shared<BitCodeAbbrev>();
4270     StackIdAbbv->Add(BitCodeAbbrevOp(bitc::FS_STACK_IDS));
4271     // numids x stackid
4272     StackIdAbbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4273     StackIdAbbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4274     unsigned StackIdAbbvId = Stream.EmitAbbrev(std::move(StackIdAbbv));
4275     // Write the stack ids used by this index, which will be a subset of those in
4276     // the full index in the case of distributed indexes.
4277     std::vector<uint64_t> StackIds;
4278     for (auto &I : StackIdIndices)
4279       StackIds.push_back(Index.getStackIdAtIndex(I));
4280     Stream.EmitRecord(bitc::FS_STACK_IDS, StackIds, StackIdAbbvId);
4281   }
4282 
4283   // Abbrev for FS_COMBINED.
4284   auto Abbv = std::make_shared<BitCodeAbbrev>();
4285   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED));
4286   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4287   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4288   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4289   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4290   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4291   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
4292   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4293   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4294   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4295   // numrefs x valueid, n x (valueid)
4296   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4297   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4298   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4299 
4300   // Abbrev for FS_COMBINED_PROFILE.
4301   Abbv = std::make_shared<BitCodeAbbrev>();
4302   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_PROFILE));
4303   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4304   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4305   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4306   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4307   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4308   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
4309   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4310   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4311   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4312   // numrefs x valueid, n x (valueid, hotness)
4313   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4314   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4315   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4316 
4317   // Abbrev for FS_COMBINED_GLOBALVAR_INIT_REFS.
4318   Abbv = std::make_shared<BitCodeAbbrev>();
4319   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS));
4320   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4321   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4322   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4323   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));    // valueids
4324   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4325   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4326 
4327   // Abbrev for FS_COMBINED_ALIAS.
4328   Abbv = std::make_shared<BitCodeAbbrev>();
4329   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_ALIAS));
4330   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4331   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4332   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4333   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4334   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4335 
4336   Abbv = std::make_shared<BitCodeAbbrev>();
4337   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_CALLSITE_INFO));
4338   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
4339   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numstackindices
4340   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numver
4341   // numstackindices x stackidindex, numver x version
4342   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4343   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4344   unsigned CallsiteAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4345 
4346   Abbv = std::make_shared<BitCodeAbbrev>();
4347   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_ALLOC_INFO));
4348   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // nummib
4349   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numver
4350   // nummib x (alloc type, numstackids, numstackids x stackidindex),
4351   // numver x version
4352   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4353   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4354   unsigned AllocAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4355 
4356   // The aliases are emitted as a post-pass, and will point to the value
4357   // id of the aliasee. Save them in a vector for post-processing.
4358   SmallVector<AliasSummary *, 64> Aliases;
4359 
4360   // Save the value id for each summary for alias emission.
4361   DenseMap<const GlobalValueSummary *, unsigned> SummaryToValueIdMap;
4362 
4363   SmallVector<uint64_t, 64> NameVals;
4364 
4365   // Set that will be populated during call to writeFunctionTypeMetadataRecords
4366   // with the type ids referenced by this index file.
4367   std::set<GlobalValue::GUID> ReferencedTypeIds;
4368 
4369   // For local linkage, we also emit the original name separately
4370   // immediately after the record.
4371   auto MaybeEmitOriginalName = [&](GlobalValueSummary &S) {
4372     // We don't need to emit the original name if we are writing the index for
4373     // distributed backends (in which case ModuleToSummariesForIndex is
4374     // non-null). The original name is only needed during the thin link, since
4375     // for SamplePGO the indirect call targets for local functions have
4376     // have the original name annotated in profile.
4377     // Continue to emit it when writing out the entire combined index, which is
4378     // used in testing the thin link via llvm-lto.
4379     if (ModuleToSummariesForIndex || !GlobalValue::isLocalLinkage(S.linkage()))
4380       return;
4381     NameVals.push_back(S.getOriginalName());
4382     Stream.EmitRecord(bitc::FS_COMBINED_ORIGINAL_NAME, NameVals);
4383     NameVals.clear();
4384   };
4385 
4386   std::set<GlobalValue::GUID> DefOrUseGUIDs;
4387   forEachSummary([&](GVInfo I, bool IsAliasee) {
4388     GlobalValueSummary *S = I.second;
4389     assert(S);
4390     DefOrUseGUIDs.insert(I.first);
4391     for (const ValueInfo &VI : S->refs())
4392       DefOrUseGUIDs.insert(VI.getGUID());
4393 
4394     auto ValueId = getValueId(I.first);
4395     assert(ValueId);
4396     SummaryToValueIdMap[S] = *ValueId;
4397 
4398     // If this is invoked for an aliasee, we want to record the above
4399     // mapping, but then not emit a summary entry (if the aliasee is
4400     // to be imported, we will invoke this separately with IsAliasee=false).
4401     if (IsAliasee)
4402       return;
4403 
4404     if (auto *AS = dyn_cast<AliasSummary>(S)) {
4405       // Will process aliases as a post-pass because the reader wants all
4406       // global to be loaded first.
4407       Aliases.push_back(AS);
4408       return;
4409     }
4410 
4411     if (auto *VS = dyn_cast<GlobalVarSummary>(S)) {
4412       NameVals.push_back(*ValueId);
4413       NameVals.push_back(Index.getModuleId(VS->modulePath()));
4414       NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
4415       NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
4416       for (auto &RI : VS->refs()) {
4417         auto RefValueId = getValueId(RI.getGUID());
4418         if (!RefValueId)
4419           continue;
4420         NameVals.push_back(*RefValueId);
4421       }
4422 
4423       // Emit the finished record.
4424       Stream.EmitRecord(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS, NameVals,
4425                         FSModRefsAbbrev);
4426       NameVals.clear();
4427       MaybeEmitOriginalName(*S);
4428       return;
4429     }
4430 
4431     auto GetValueId = [&](const ValueInfo &VI) -> std::optional<unsigned> {
4432       if (!VI)
4433         return std::nullopt;
4434       return getValueId(VI.getGUID());
4435     };
4436 
4437     auto *FS = cast<FunctionSummary>(S);
4438     writeFunctionTypeMetadataRecords(Stream, FS, GetValueId);
4439     getReferencedTypeIds(FS, ReferencedTypeIds);
4440 
4441     writeFunctionHeapProfileRecords(
4442         Stream, FS, CallsiteAbbrev, AllocAbbrev,
4443         /*PerModule*/ false,
4444         /*GetValueId*/ [&](const ValueInfo &VI) -> unsigned {
4445           std::optional<unsigned> ValueID = GetValueId(VI);
4446           // This can happen in shared index files for distributed ThinLTO if
4447           // the callee function summary is not included. Record 0 which we
4448           // will have to deal with conservatively when doing any kind of
4449           // validation in the ThinLTO backends.
4450           if (!ValueID)
4451             return 0;
4452           return *ValueID;
4453         },
4454         /*GetStackIndex*/ [&](unsigned I) {
4455           // Get the corresponding index into the list of StackIdIndices
4456           // actually being written for this combined index (which may be a
4457           // subset in the case of distributed indexes).
4458           auto Lower = llvm::lower_bound(StackIdIndices, I);
4459           return std::distance(StackIdIndices.begin(), Lower);
4460         });
4461 
4462     NameVals.push_back(*ValueId);
4463     NameVals.push_back(Index.getModuleId(FS->modulePath()));
4464     NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
4465     NameVals.push_back(FS->instCount());
4466     NameVals.push_back(getEncodedFFlags(FS->fflags()));
4467     NameVals.push_back(FS->entryCount());
4468 
4469     // Fill in below
4470     NameVals.push_back(0); // numrefs
4471     NameVals.push_back(0); // rorefcnt
4472     NameVals.push_back(0); // worefcnt
4473 
4474     unsigned Count = 0, RORefCnt = 0, WORefCnt = 0;
4475     for (auto &RI : FS->refs()) {
4476       auto RefValueId = getValueId(RI.getGUID());
4477       if (!RefValueId)
4478         continue;
4479       NameVals.push_back(*RefValueId);
4480       if (RI.isReadOnly())
4481         RORefCnt++;
4482       else if (RI.isWriteOnly())
4483         WORefCnt++;
4484       Count++;
4485     }
4486     NameVals[6] = Count;
4487     NameVals[7] = RORefCnt;
4488     NameVals[8] = WORefCnt;
4489 
4490     bool HasProfileData = false;
4491     for (auto &EI : FS->calls()) {
4492       HasProfileData |=
4493           EI.second.getHotness() != CalleeInfo::HotnessType::Unknown;
4494       if (HasProfileData)
4495         break;
4496     }
4497 
4498     for (auto &EI : FS->calls()) {
4499       // If this GUID doesn't have a value id, it doesn't have a function
4500       // summary and we don't need to record any calls to it.
4501       std::optional<unsigned> CallValueId = GetValueId(EI.first);
4502       if (!CallValueId)
4503         continue;
4504       NameVals.push_back(*CallValueId);
4505       if (HasProfileData)
4506         NameVals.push_back(static_cast<uint8_t>(EI.second.Hotness));
4507     }
4508 
4509     unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
4510     unsigned Code =
4511         (HasProfileData ? bitc::FS_COMBINED_PROFILE : bitc::FS_COMBINED);
4512 
4513     // Emit the finished record.
4514     Stream.EmitRecord(Code, NameVals, FSAbbrev);
4515     NameVals.clear();
4516     MaybeEmitOriginalName(*S);
4517   });
4518 
4519   for (auto *AS : Aliases) {
4520     auto AliasValueId = SummaryToValueIdMap[AS];
4521     assert(AliasValueId);
4522     NameVals.push_back(AliasValueId);
4523     NameVals.push_back(Index.getModuleId(AS->modulePath()));
4524     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
4525     auto AliaseeValueId = SummaryToValueIdMap[&AS->getAliasee()];
4526     assert(AliaseeValueId);
4527     NameVals.push_back(AliaseeValueId);
4528 
4529     // Emit the finished record.
4530     Stream.EmitRecord(bitc::FS_COMBINED_ALIAS, NameVals, FSAliasAbbrev);
4531     NameVals.clear();
4532     MaybeEmitOriginalName(*AS);
4533 
4534     if (auto *FS = dyn_cast<FunctionSummary>(&AS->getAliasee()))
4535       getReferencedTypeIds(FS, ReferencedTypeIds);
4536   }
4537 
4538   if (!Index.cfiFunctionDefs().empty()) {
4539     for (auto &S : Index.cfiFunctionDefs()) {
4540       if (DefOrUseGUIDs.count(
4541               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4542         NameVals.push_back(StrtabBuilder.add(S));
4543         NameVals.push_back(S.size());
4544       }
4545     }
4546     if (!NameVals.empty()) {
4547       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DEFS, NameVals);
4548       NameVals.clear();
4549     }
4550   }
4551 
4552   if (!Index.cfiFunctionDecls().empty()) {
4553     for (auto &S : Index.cfiFunctionDecls()) {
4554       if (DefOrUseGUIDs.count(
4555               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4556         NameVals.push_back(StrtabBuilder.add(S));
4557         NameVals.push_back(S.size());
4558       }
4559     }
4560     if (!NameVals.empty()) {
4561       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DECLS, NameVals);
4562       NameVals.clear();
4563     }
4564   }
4565 
4566   // Walk the GUIDs that were referenced, and write the
4567   // corresponding type id records.
4568   for (auto &T : ReferencedTypeIds) {
4569     auto TidIter = Index.typeIds().equal_range(T);
4570     for (auto It = TidIter.first; It != TidIter.second; ++It) {
4571       writeTypeIdSummaryRecord(NameVals, StrtabBuilder, It->second.first,
4572                                It->second.second);
4573       Stream.EmitRecord(bitc::FS_TYPE_ID, NameVals);
4574       NameVals.clear();
4575     }
4576   }
4577 
4578   Stream.EmitRecord(bitc::FS_BLOCK_COUNT,
4579                     ArrayRef<uint64_t>{Index.getBlockCount()});
4580 
4581   Stream.ExitBlock();
4582 }
4583 
4584 /// Create the "IDENTIFICATION_BLOCK_ID" containing a single string with the
4585 /// current llvm version, and a record for the epoch number.
4586 static void writeIdentificationBlock(BitstreamWriter &Stream) {
4587   Stream.EnterSubblock(bitc::IDENTIFICATION_BLOCK_ID, 5);
4588 
4589   // Write the "user readable" string identifying the bitcode producer
4590   auto Abbv = std::make_shared<BitCodeAbbrev>();
4591   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_STRING));
4592   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4593   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
4594   auto StringAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4595   writeStringRecord(Stream, bitc::IDENTIFICATION_CODE_STRING,
4596                     "LLVM" LLVM_VERSION_STRING, StringAbbrev);
4597 
4598   // Write the epoch version
4599   Abbv = std::make_shared<BitCodeAbbrev>();
4600   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_EPOCH));
4601   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
4602   auto EpochAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4603   constexpr std::array<unsigned, 1> Vals = {{bitc::BITCODE_CURRENT_EPOCH}};
4604   Stream.EmitRecord(bitc::IDENTIFICATION_CODE_EPOCH, Vals, EpochAbbrev);
4605   Stream.ExitBlock();
4606 }
4607 
4608 void ModuleBitcodeWriter::writeModuleHash(size_t BlockStartPos) {
4609   // Emit the module's hash.
4610   // MODULE_CODE_HASH: [5*i32]
4611   if (GenerateHash) {
4612     uint32_t Vals[5];
4613     Hasher.update(ArrayRef<uint8_t>((const uint8_t *)&(Buffer)[BlockStartPos],
4614                                     Buffer.size() - BlockStartPos));
4615     std::array<uint8_t, 20> Hash = Hasher.result();
4616     for (int Pos = 0; Pos < 20; Pos += 4) {
4617       Vals[Pos / 4] = support::endian::read32be(Hash.data() + Pos);
4618     }
4619 
4620     // Emit the finished record.
4621     Stream.EmitRecord(bitc::MODULE_CODE_HASH, Vals);
4622 
4623     if (ModHash)
4624       // Save the written hash value.
4625       llvm::copy(Vals, std::begin(*ModHash));
4626   }
4627 }
4628 
4629 void ModuleBitcodeWriter::write() {
4630   writeIdentificationBlock(Stream);
4631 
4632   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4633   size_t BlockStartPos = Buffer.size();
4634 
4635   writeModuleVersion();
4636 
4637   // Emit blockinfo, which defines the standard abbreviations etc.
4638   writeBlockInfo();
4639 
4640   // Emit information describing all of the types in the module.
4641   writeTypeTable();
4642 
4643   // Emit information about attribute groups.
4644   writeAttributeGroupTable();
4645 
4646   // Emit information about parameter attributes.
4647   writeAttributeTable();
4648 
4649   writeComdats();
4650 
4651   // Emit top-level description of module, including target triple, inline asm,
4652   // descriptors for global variables, and function prototype info.
4653   writeModuleInfo();
4654 
4655   // Emit constants.
4656   writeModuleConstants();
4657 
4658   // Emit metadata kind names.
4659   writeModuleMetadataKinds();
4660 
4661   // Emit metadata.
4662   writeModuleMetadata();
4663 
4664   // Emit module-level use-lists.
4665   if (VE.shouldPreserveUseListOrder())
4666     writeUseListBlock(nullptr);
4667 
4668   writeOperandBundleTags();
4669   writeSyncScopeNames();
4670 
4671   // Emit function bodies.
4672   DenseMap<const Function *, uint64_t> FunctionToBitcodeIndex;
4673   for (const Function &F : M)
4674     if (!F.isDeclaration())
4675       writeFunction(F, FunctionToBitcodeIndex);
4676 
4677   // Need to write after the above call to WriteFunction which populates
4678   // the summary information in the index.
4679   if (Index)
4680     writePerModuleGlobalValueSummary();
4681 
4682   writeGlobalValueSymbolTable(FunctionToBitcodeIndex);
4683 
4684   writeModuleHash(BlockStartPos);
4685 
4686   Stream.ExitBlock();
4687 }
4688 
4689 static void writeInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
4690                                uint32_t &Position) {
4691   support::endian::write32le(&Buffer[Position], Value);
4692   Position += 4;
4693 }
4694 
4695 /// If generating a bc file on darwin, we have to emit a
4696 /// header and trailer to make it compatible with the system archiver.  To do
4697 /// this we emit the following header, and then emit a trailer that pads the
4698 /// file out to be a multiple of 16 bytes.
4699 ///
4700 /// struct bc_header {
4701 ///   uint32_t Magic;         // 0x0B17C0DE
4702 ///   uint32_t Version;       // Version, currently always 0.
4703 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
4704 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
4705 ///   uint32_t CPUType;       // CPU specifier.
4706 ///   ... potentially more later ...
4707 /// };
4708 static void emitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
4709                                          const Triple &TT) {
4710   unsigned CPUType = ~0U;
4711 
4712   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
4713   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
4714   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
4715   // specific constants here because they are implicitly part of the Darwin ABI.
4716   enum {
4717     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
4718     DARWIN_CPU_TYPE_X86        = 7,
4719     DARWIN_CPU_TYPE_ARM        = 12,
4720     DARWIN_CPU_TYPE_POWERPC    = 18
4721   };
4722 
4723   Triple::ArchType Arch = TT.getArch();
4724   if (Arch == Triple::x86_64)
4725     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
4726   else if (Arch == Triple::x86)
4727     CPUType = DARWIN_CPU_TYPE_X86;
4728   else if (Arch == Triple::ppc)
4729     CPUType = DARWIN_CPU_TYPE_POWERPC;
4730   else if (Arch == Triple::ppc64)
4731     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
4732   else if (Arch == Triple::arm || Arch == Triple::thumb)
4733     CPUType = DARWIN_CPU_TYPE_ARM;
4734 
4735   // Traditional Bitcode starts after header.
4736   assert(Buffer.size() >= BWH_HeaderSize &&
4737          "Expected header size to be reserved");
4738   unsigned BCOffset = BWH_HeaderSize;
4739   unsigned BCSize = Buffer.size() - BWH_HeaderSize;
4740 
4741   // Write the magic and version.
4742   unsigned Position = 0;
4743   writeInt32ToBuffer(0x0B17C0DE, Buffer, Position);
4744   writeInt32ToBuffer(0, Buffer, Position); // Version.
4745   writeInt32ToBuffer(BCOffset, Buffer, Position);
4746   writeInt32ToBuffer(BCSize, Buffer, Position);
4747   writeInt32ToBuffer(CPUType, Buffer, Position);
4748 
4749   // If the file is not a multiple of 16 bytes, insert dummy padding.
4750   while (Buffer.size() & 15)
4751     Buffer.push_back(0);
4752 }
4753 
4754 /// Helper to write the header common to all bitcode files.
4755 static void writeBitcodeHeader(BitstreamWriter &Stream) {
4756   // Emit the file header.
4757   Stream.Emit((unsigned)'B', 8);
4758   Stream.Emit((unsigned)'C', 8);
4759   Stream.Emit(0x0, 4);
4760   Stream.Emit(0xC, 4);
4761   Stream.Emit(0xE, 4);
4762   Stream.Emit(0xD, 4);
4763 }
4764 
4765 BitcodeWriter::BitcodeWriter(SmallVectorImpl<char> &Buffer, raw_fd_stream *FS)
4766     : Buffer(Buffer), Stream(new BitstreamWriter(Buffer, FS, FlushThreshold)) {
4767   writeBitcodeHeader(*Stream);
4768 }
4769 
4770 BitcodeWriter::~BitcodeWriter() { assert(WroteStrtab); }
4771 
4772 void BitcodeWriter::writeBlob(unsigned Block, unsigned Record, StringRef Blob) {
4773   Stream->EnterSubblock(Block, 3);
4774 
4775   auto Abbv = std::make_shared<BitCodeAbbrev>();
4776   Abbv->Add(BitCodeAbbrevOp(Record));
4777   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
4778   auto AbbrevNo = Stream->EmitAbbrev(std::move(Abbv));
4779 
4780   Stream->EmitRecordWithBlob(AbbrevNo, ArrayRef<uint64_t>{Record}, Blob);
4781 
4782   Stream->ExitBlock();
4783 }
4784 
4785 void BitcodeWriter::writeSymtab() {
4786   assert(!WroteStrtab && !WroteSymtab);
4787 
4788   // If any module has module-level inline asm, we will require a registered asm
4789   // parser for the target so that we can create an accurate symbol table for
4790   // the module.
4791   for (Module *M : Mods) {
4792     if (M->getModuleInlineAsm().empty())
4793       continue;
4794 
4795     std::string Err;
4796     const Triple TT(M->getTargetTriple());
4797     const Target *T = TargetRegistry::lookupTarget(TT.str(), Err);
4798     if (!T || !T->hasMCAsmParser())
4799       return;
4800   }
4801 
4802   WroteSymtab = true;
4803   SmallVector<char, 0> Symtab;
4804   // The irsymtab::build function may be unable to create a symbol table if the
4805   // module is malformed (e.g. it contains an invalid alias). Writing a symbol
4806   // table is not required for correctness, but we still want to be able to
4807   // write malformed modules to bitcode files, so swallow the error.
4808   if (Error E = irsymtab::build(Mods, Symtab, StrtabBuilder, Alloc)) {
4809     consumeError(std::move(E));
4810     return;
4811   }
4812 
4813   writeBlob(bitc::SYMTAB_BLOCK_ID, bitc::SYMTAB_BLOB,
4814             {Symtab.data(), Symtab.size()});
4815 }
4816 
4817 void BitcodeWriter::writeStrtab() {
4818   assert(!WroteStrtab);
4819 
4820   std::vector<char> Strtab;
4821   StrtabBuilder.finalizeInOrder();
4822   Strtab.resize(StrtabBuilder.getSize());
4823   StrtabBuilder.write((uint8_t *)Strtab.data());
4824 
4825   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB,
4826             {Strtab.data(), Strtab.size()});
4827 
4828   WroteStrtab = true;
4829 }
4830 
4831 void BitcodeWriter::copyStrtab(StringRef Strtab) {
4832   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB, Strtab);
4833   WroteStrtab = true;
4834 }
4835 
4836 void BitcodeWriter::writeModule(const Module &M,
4837                                 bool ShouldPreserveUseListOrder,
4838                                 const ModuleSummaryIndex *Index,
4839                                 bool GenerateHash, ModuleHash *ModHash) {
4840   assert(!WroteStrtab);
4841 
4842   // The Mods vector is used by irsymtab::build, which requires non-const
4843   // Modules in case it needs to materialize metadata. But the bitcode writer
4844   // requires that the module is materialized, so we can cast to non-const here,
4845   // after checking that it is in fact materialized.
4846   assert(M.isMaterialized());
4847   Mods.push_back(const_cast<Module *>(&M));
4848 
4849   ModuleBitcodeWriter ModuleWriter(M, Buffer, StrtabBuilder, *Stream,
4850                                    ShouldPreserveUseListOrder, Index,
4851                                    GenerateHash, ModHash);
4852   ModuleWriter.write();
4853 }
4854 
4855 void BitcodeWriter::writeIndex(
4856     const ModuleSummaryIndex *Index,
4857     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4858   IndexBitcodeWriter IndexWriter(*Stream, StrtabBuilder, *Index,
4859                                  ModuleToSummariesForIndex);
4860   IndexWriter.write();
4861 }
4862 
4863 /// Write the specified module to the specified output stream.
4864 void llvm::WriteBitcodeToFile(const Module &M, raw_ostream &Out,
4865                               bool ShouldPreserveUseListOrder,
4866                               const ModuleSummaryIndex *Index,
4867                               bool GenerateHash, ModuleHash *ModHash) {
4868   SmallVector<char, 0> Buffer;
4869   Buffer.reserve(256*1024);
4870 
4871   // If this is darwin or another generic macho target, reserve space for the
4872   // header.
4873   Triple TT(M.getTargetTriple());
4874   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4875     Buffer.insert(Buffer.begin(), BWH_HeaderSize, 0);
4876 
4877   BitcodeWriter Writer(Buffer, dyn_cast<raw_fd_stream>(&Out));
4878   Writer.writeModule(M, ShouldPreserveUseListOrder, Index, GenerateHash,
4879                      ModHash);
4880   Writer.writeSymtab();
4881   Writer.writeStrtab();
4882 
4883   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4884     emitDarwinBCHeaderAndTrailer(Buffer, TT);
4885 
4886   // Write the generated bitstream to "Out".
4887   if (!Buffer.empty())
4888     Out.write((char *)&Buffer.front(), Buffer.size());
4889 }
4890 
4891 void IndexBitcodeWriter::write() {
4892   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4893 
4894   writeModuleVersion();
4895 
4896   // Write the module paths in the combined index.
4897   writeModStrings();
4898 
4899   // Write the summary combined index records.
4900   writeCombinedGlobalValueSummary();
4901 
4902   Stream.ExitBlock();
4903 }
4904 
4905 // Write the specified module summary index to the given raw output stream,
4906 // where it will be written in a new bitcode block. This is used when
4907 // writing the combined index file for ThinLTO. When writing a subset of the
4908 // index for a distributed backend, provide a \p ModuleToSummariesForIndex map.
4909 void llvm::writeIndexToFile(
4910     const ModuleSummaryIndex &Index, raw_ostream &Out,
4911     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4912   SmallVector<char, 0> Buffer;
4913   Buffer.reserve(256 * 1024);
4914 
4915   BitcodeWriter Writer(Buffer);
4916   Writer.writeIndex(&Index, ModuleToSummariesForIndex);
4917   Writer.writeStrtab();
4918 
4919   Out.write((char *)&Buffer.front(), Buffer.size());
4920 }
4921 
4922 namespace {
4923 
4924 /// Class to manage the bitcode writing for a thin link bitcode file.
4925 class ThinLinkBitcodeWriter : public ModuleBitcodeWriterBase {
4926   /// ModHash is for use in ThinLTO incremental build, generated while writing
4927   /// the module bitcode file.
4928   const ModuleHash *ModHash;
4929 
4930 public:
4931   ThinLinkBitcodeWriter(const Module &M, StringTableBuilder &StrtabBuilder,
4932                         BitstreamWriter &Stream,
4933                         const ModuleSummaryIndex &Index,
4934                         const ModuleHash &ModHash)
4935       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
4936                                 /*ShouldPreserveUseListOrder=*/false, &Index),
4937         ModHash(&ModHash) {}
4938 
4939   void write();
4940 
4941 private:
4942   void writeSimplifiedModuleInfo();
4943 };
4944 
4945 } // end anonymous namespace
4946 
4947 // This function writes a simpilified module info for thin link bitcode file.
4948 // It only contains the source file name along with the name(the offset and
4949 // size in strtab) and linkage for global values. For the global value info
4950 // entry, in order to keep linkage at offset 5, there are three zeros used
4951 // as padding.
4952 void ThinLinkBitcodeWriter::writeSimplifiedModuleInfo() {
4953   SmallVector<unsigned, 64> Vals;
4954   // Emit the module's source file name.
4955   {
4956     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
4957     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
4958     if (Bits == SE_Char6)
4959       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
4960     else if (Bits == SE_Fixed7)
4961       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
4962 
4963     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
4964     auto Abbv = std::make_shared<BitCodeAbbrev>();
4965     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
4966     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4967     Abbv->Add(AbbrevOpToUse);
4968     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4969 
4970     for (const auto P : M.getSourceFileName())
4971       Vals.push_back((unsigned char)P);
4972 
4973     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
4974     Vals.clear();
4975   }
4976 
4977   // Emit the global variable information.
4978   for (const GlobalVariable &GV : M.globals()) {
4979     // GLOBALVAR: [strtab offset, strtab size, 0, 0, 0, linkage]
4980     Vals.push_back(StrtabBuilder.add(GV.getName()));
4981     Vals.push_back(GV.getName().size());
4982     Vals.push_back(0);
4983     Vals.push_back(0);
4984     Vals.push_back(0);
4985     Vals.push_back(getEncodedLinkage(GV));
4986 
4987     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals);
4988     Vals.clear();
4989   }
4990 
4991   // Emit the function proto information.
4992   for (const Function &F : M) {
4993     // FUNCTION:  [strtab offset, strtab size, 0, 0, 0, linkage]
4994     Vals.push_back(StrtabBuilder.add(F.getName()));
4995     Vals.push_back(F.getName().size());
4996     Vals.push_back(0);
4997     Vals.push_back(0);
4998     Vals.push_back(0);
4999     Vals.push_back(getEncodedLinkage(F));
5000 
5001     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals);
5002     Vals.clear();
5003   }
5004 
5005   // Emit the alias information.
5006   for (const GlobalAlias &A : M.aliases()) {
5007     // ALIAS: [strtab offset, strtab size, 0, 0, 0, linkage]
5008     Vals.push_back(StrtabBuilder.add(A.getName()));
5009     Vals.push_back(A.getName().size());
5010     Vals.push_back(0);
5011     Vals.push_back(0);
5012     Vals.push_back(0);
5013     Vals.push_back(getEncodedLinkage(A));
5014 
5015     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals);
5016     Vals.clear();
5017   }
5018 
5019   // Emit the ifunc information.
5020   for (const GlobalIFunc &I : M.ifuncs()) {
5021     // IFUNC: [strtab offset, strtab size, 0, 0, 0, linkage]
5022     Vals.push_back(StrtabBuilder.add(I.getName()));
5023     Vals.push_back(I.getName().size());
5024     Vals.push_back(0);
5025     Vals.push_back(0);
5026     Vals.push_back(0);
5027     Vals.push_back(getEncodedLinkage(I));
5028 
5029     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
5030     Vals.clear();
5031   }
5032 }
5033 
5034 void ThinLinkBitcodeWriter::write() {
5035   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
5036 
5037   writeModuleVersion();
5038 
5039   writeSimplifiedModuleInfo();
5040 
5041   writePerModuleGlobalValueSummary();
5042 
5043   // Write module hash.
5044   Stream.EmitRecord(bitc::MODULE_CODE_HASH, ArrayRef<uint32_t>(*ModHash));
5045 
5046   Stream.ExitBlock();
5047 }
5048 
5049 void BitcodeWriter::writeThinLinkBitcode(const Module &M,
5050                                          const ModuleSummaryIndex &Index,
5051                                          const ModuleHash &ModHash) {
5052   assert(!WroteStrtab);
5053 
5054   // The Mods vector is used by irsymtab::build, which requires non-const
5055   // Modules in case it needs to materialize metadata. But the bitcode writer
5056   // requires that the module is materialized, so we can cast to non-const here,
5057   // after checking that it is in fact materialized.
5058   assert(M.isMaterialized());
5059   Mods.push_back(const_cast<Module *>(&M));
5060 
5061   ThinLinkBitcodeWriter ThinLinkWriter(M, StrtabBuilder, *Stream, Index,
5062                                        ModHash);
5063   ThinLinkWriter.write();
5064 }
5065 
5066 // Write the specified thin link bitcode file to the given raw output stream,
5067 // where it will be written in a new bitcode block. This is used when
5068 // writing the per-module index file for ThinLTO.
5069 void llvm::writeThinLinkBitcodeToFile(const Module &M, raw_ostream &Out,
5070                                       const ModuleSummaryIndex &Index,
5071                                       const ModuleHash &ModHash) {
5072   SmallVector<char, 0> Buffer;
5073   Buffer.reserve(256 * 1024);
5074 
5075   BitcodeWriter Writer(Buffer);
5076   Writer.writeThinLinkBitcode(M, Index, ModHash);
5077   Writer.writeSymtab();
5078   Writer.writeStrtab();
5079 
5080   Out.write((char *)&Buffer.front(), Buffer.size());
5081 }
5082 
5083 static const char *getSectionNameForBitcode(const Triple &T) {
5084   switch (T.getObjectFormat()) {
5085   case Triple::MachO:
5086     return "__LLVM,__bitcode";
5087   case Triple::COFF:
5088   case Triple::ELF:
5089   case Triple::Wasm:
5090   case Triple::UnknownObjectFormat:
5091     return ".llvmbc";
5092   case Triple::GOFF:
5093     llvm_unreachable("GOFF is not yet implemented");
5094     break;
5095   case Triple::SPIRV:
5096     llvm_unreachable("SPIRV is not yet implemented");
5097     break;
5098   case Triple::XCOFF:
5099     llvm_unreachable("XCOFF is not yet implemented");
5100     break;
5101   case Triple::DXContainer:
5102     llvm_unreachable("DXContainer is not yet implemented");
5103     break;
5104   }
5105   llvm_unreachable("Unimplemented ObjectFormatType");
5106 }
5107 
5108 static const char *getSectionNameForCommandline(const Triple &T) {
5109   switch (T.getObjectFormat()) {
5110   case Triple::MachO:
5111     return "__LLVM,__cmdline";
5112   case Triple::COFF:
5113   case Triple::ELF:
5114   case Triple::Wasm:
5115   case Triple::UnknownObjectFormat:
5116     return ".llvmcmd";
5117   case Triple::GOFF:
5118     llvm_unreachable("GOFF is not yet implemented");
5119     break;
5120   case Triple::SPIRV:
5121     llvm_unreachable("SPIRV is not yet implemented");
5122     break;
5123   case Triple::XCOFF:
5124     llvm_unreachable("XCOFF is not yet implemented");
5125     break;
5126   case Triple::DXContainer:
5127     llvm_unreachable("DXC is not yet implemented");
5128     break;
5129   }
5130   llvm_unreachable("Unimplemented ObjectFormatType");
5131 }
5132 
5133 void llvm::embedBitcodeInModule(llvm::Module &M, llvm::MemoryBufferRef Buf,
5134                                 bool EmbedBitcode, bool EmbedCmdline,
5135                                 const std::vector<uint8_t> &CmdArgs) {
5136   // Save llvm.compiler.used and remove it.
5137   SmallVector<Constant *, 2> UsedArray;
5138   SmallVector<GlobalValue *, 4> UsedGlobals;
5139   Type *UsedElementType = Type::getInt8Ty(M.getContext())->getPointerTo(0);
5140   GlobalVariable *Used = collectUsedGlobalVariables(M, UsedGlobals, true);
5141   for (auto *GV : UsedGlobals) {
5142     if (GV->getName() != "llvm.embedded.module" &&
5143         GV->getName() != "llvm.cmdline")
5144       UsedArray.push_back(
5145           ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
5146   }
5147   if (Used)
5148     Used->eraseFromParent();
5149 
5150   // Embed the bitcode for the llvm module.
5151   std::string Data;
5152   ArrayRef<uint8_t> ModuleData;
5153   Triple T(M.getTargetTriple());
5154 
5155   if (EmbedBitcode) {
5156     if (Buf.getBufferSize() == 0 ||
5157         !isBitcode((const unsigned char *)Buf.getBufferStart(),
5158                    (const unsigned char *)Buf.getBufferEnd())) {
5159       // If the input is LLVM Assembly, bitcode is produced by serializing
5160       // the module. Use-lists order need to be preserved in this case.
5161       llvm::raw_string_ostream OS(Data);
5162       llvm::WriteBitcodeToFile(M, OS, /* ShouldPreserveUseListOrder */ true);
5163       ModuleData =
5164           ArrayRef<uint8_t>((const uint8_t *)OS.str().data(), OS.str().size());
5165     } else
5166       // If the input is LLVM bitcode, write the input byte stream directly.
5167       ModuleData = ArrayRef<uint8_t>((const uint8_t *)Buf.getBufferStart(),
5168                                      Buf.getBufferSize());
5169   }
5170   llvm::Constant *ModuleConstant =
5171       llvm::ConstantDataArray::get(M.getContext(), ModuleData);
5172   llvm::GlobalVariable *GV = new llvm::GlobalVariable(
5173       M, ModuleConstant->getType(), true, llvm::GlobalValue::PrivateLinkage,
5174       ModuleConstant);
5175   GV->setSection(getSectionNameForBitcode(T));
5176   // Set alignment to 1 to prevent padding between two contributions from input
5177   // sections after linking.
5178   GV->setAlignment(Align(1));
5179   UsedArray.push_back(
5180       ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
5181   if (llvm::GlobalVariable *Old =
5182           M.getGlobalVariable("llvm.embedded.module", true)) {
5183     assert(Old->hasZeroLiveUses() &&
5184            "llvm.embedded.module can only be used once in llvm.compiler.used");
5185     GV->takeName(Old);
5186     Old->eraseFromParent();
5187   } else {
5188     GV->setName("llvm.embedded.module");
5189   }
5190 
5191   // Skip if only bitcode needs to be embedded.
5192   if (EmbedCmdline) {
5193     // Embed command-line options.
5194     ArrayRef<uint8_t> CmdData(const_cast<uint8_t *>(CmdArgs.data()),
5195                               CmdArgs.size());
5196     llvm::Constant *CmdConstant =
5197         llvm::ConstantDataArray::get(M.getContext(), CmdData);
5198     GV = new llvm::GlobalVariable(M, CmdConstant->getType(), true,
5199                                   llvm::GlobalValue::PrivateLinkage,
5200                                   CmdConstant);
5201     GV->setSection(getSectionNameForCommandline(T));
5202     GV->setAlignment(Align(1));
5203     UsedArray.push_back(
5204         ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
5205     if (llvm::GlobalVariable *Old = M.getGlobalVariable("llvm.cmdline", true)) {
5206       assert(Old->hasZeroLiveUses() &&
5207              "llvm.cmdline can only be used once in llvm.compiler.used");
5208       GV->takeName(Old);
5209       Old->eraseFromParent();
5210     } else {
5211       GV->setName("llvm.cmdline");
5212     }
5213   }
5214 
5215   if (UsedArray.empty())
5216     return;
5217 
5218   // Recreate llvm.compiler.used.
5219   ArrayType *ATy = ArrayType::get(UsedElementType, UsedArray.size());
5220   auto *NewUsed = new GlobalVariable(
5221       M, ATy, false, llvm::GlobalValue::AppendingLinkage,
5222       llvm::ConstantArray::get(ATy, UsedArray), "llvm.compiler.used");
5223   NewUsed->setSection("llvm.metadata");
5224 }
5225