xref: /llvm-project/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp (revision bbe8cd13335300958b04db5318c31ff52714f96f)
1 //===- Bitcode/Writer/BitcodeWriter.cpp - Bitcode Writer ------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // Bitcode writer implementation.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "llvm/Bitcode/BitcodeWriter.h"
14 #include "ValueEnumerator.h"
15 #include "llvm/ADT/APFloat.h"
16 #include "llvm/ADT/APInt.h"
17 #include "llvm/ADT/ArrayRef.h"
18 #include "llvm/ADT/DenseMap.h"
19 #include "llvm/ADT/STLExtras.h"
20 #include "llvm/ADT/SetVector.h"
21 #include "llvm/ADT/SmallPtrSet.h"
22 #include "llvm/ADT/SmallString.h"
23 #include "llvm/ADT/SmallVector.h"
24 #include "llvm/ADT/StringMap.h"
25 #include "llvm/ADT/StringRef.h"
26 #include "llvm/Bitcode/BitcodeCommon.h"
27 #include "llvm/Bitcode/BitcodeReader.h"
28 #include "llvm/Bitcode/LLVMBitCodes.h"
29 #include "llvm/Bitstream/BitCodes.h"
30 #include "llvm/Bitstream/BitstreamWriter.h"
31 #include "llvm/Config/llvm-config.h"
32 #include "llvm/IR/Attributes.h"
33 #include "llvm/IR/BasicBlock.h"
34 #include "llvm/IR/Comdat.h"
35 #include "llvm/IR/Constant.h"
36 #include "llvm/IR/Constants.h"
37 #include "llvm/IR/DebugInfoMetadata.h"
38 #include "llvm/IR/DebugLoc.h"
39 #include "llvm/IR/DerivedTypes.h"
40 #include "llvm/IR/Function.h"
41 #include "llvm/IR/GlobalAlias.h"
42 #include "llvm/IR/GlobalIFunc.h"
43 #include "llvm/IR/GlobalObject.h"
44 #include "llvm/IR/GlobalValue.h"
45 #include "llvm/IR/GlobalVariable.h"
46 #include "llvm/IR/InlineAsm.h"
47 #include "llvm/IR/InstrTypes.h"
48 #include "llvm/IR/Instruction.h"
49 #include "llvm/IR/Instructions.h"
50 #include "llvm/IR/LLVMContext.h"
51 #include "llvm/IR/Metadata.h"
52 #include "llvm/IR/Module.h"
53 #include "llvm/IR/ModuleSummaryIndex.h"
54 #include "llvm/IR/Operator.h"
55 #include "llvm/IR/Type.h"
56 #include "llvm/IR/UseListOrder.h"
57 #include "llvm/IR/Value.h"
58 #include "llvm/IR/ValueSymbolTable.h"
59 #include "llvm/MC/StringTableBuilder.h"
60 #include "llvm/MC/TargetRegistry.h"
61 #include "llvm/Object/IRSymtab.h"
62 #include "llvm/Support/AtomicOrdering.h"
63 #include "llvm/Support/Casting.h"
64 #include "llvm/Support/CommandLine.h"
65 #include "llvm/Support/Endian.h"
66 #include "llvm/Support/Error.h"
67 #include "llvm/Support/ErrorHandling.h"
68 #include "llvm/Support/MathExtras.h"
69 #include "llvm/Support/SHA1.h"
70 #include "llvm/Support/raw_ostream.h"
71 #include "llvm/TargetParser/Triple.h"
72 #include <algorithm>
73 #include <cassert>
74 #include <cstddef>
75 #include <cstdint>
76 #include <iterator>
77 #include <map>
78 #include <memory>
79 #include <optional>
80 #include <string>
81 #include <utility>
82 #include <vector>
83 
84 using namespace llvm;
85 
86 static cl::opt<unsigned>
87     IndexThreshold("bitcode-mdindex-threshold", cl::Hidden, cl::init(25),
88                    cl::desc("Number of metadatas above which we emit an index "
89                             "to enable lazy-loading"));
90 static cl::opt<uint32_t> FlushThreshold(
91     "bitcode-flush-threshold", cl::Hidden, cl::init(512),
92     cl::desc("The threshold (unit M) for flushing LLVM bitcode."));
93 
94 static cl::opt<bool> WriteRelBFToSummary(
95     "write-relbf-to-summary", cl::Hidden, cl::init(false),
96     cl::desc("Write relative block frequency to function summary "));
97 
98 namespace llvm {
99 extern FunctionSummary::ForceSummaryHotnessType ForceSummaryEdgesCold;
100 }
101 
102 namespace {
103 
104 /// These are manifest constants used by the bitcode writer. They do not need to
105 /// be kept in sync with the reader, but need to be consistent within this file.
106 enum {
107   // VALUE_SYMTAB_BLOCK abbrev id's.
108   VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
109   VST_ENTRY_7_ABBREV,
110   VST_ENTRY_6_ABBREV,
111   VST_BBENTRY_6_ABBREV,
112 
113   // CONSTANTS_BLOCK abbrev id's.
114   CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
115   CONSTANTS_INTEGER_ABBREV,
116   CONSTANTS_CE_CAST_Abbrev,
117   CONSTANTS_NULL_Abbrev,
118 
119   // FUNCTION_BLOCK abbrev id's.
120   FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
121   FUNCTION_INST_UNOP_ABBREV,
122   FUNCTION_INST_UNOP_FLAGS_ABBREV,
123   FUNCTION_INST_BINOP_ABBREV,
124   FUNCTION_INST_BINOP_FLAGS_ABBREV,
125   FUNCTION_INST_CAST_ABBREV,
126   FUNCTION_INST_RET_VOID_ABBREV,
127   FUNCTION_INST_RET_VAL_ABBREV,
128   FUNCTION_INST_UNREACHABLE_ABBREV,
129   FUNCTION_INST_GEP_ABBREV,
130 };
131 
132 /// Abstract class to manage the bitcode writing, subclassed for each bitcode
133 /// file type.
134 class BitcodeWriterBase {
135 protected:
136   /// The stream created and owned by the client.
137   BitstreamWriter &Stream;
138 
139   StringTableBuilder &StrtabBuilder;
140 
141 public:
142   /// Constructs a BitcodeWriterBase object that writes to the provided
143   /// \p Stream.
144   BitcodeWriterBase(BitstreamWriter &Stream, StringTableBuilder &StrtabBuilder)
145       : Stream(Stream), StrtabBuilder(StrtabBuilder) {}
146 
147 protected:
148   void writeModuleVersion();
149 };
150 
151 void BitcodeWriterBase::writeModuleVersion() {
152   // VERSION: [version#]
153   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, ArrayRef<uint64_t>{2});
154 }
155 
156 /// Base class to manage the module bitcode writing, currently subclassed for
157 /// ModuleBitcodeWriter and ThinLinkBitcodeWriter.
158 class ModuleBitcodeWriterBase : public BitcodeWriterBase {
159 protected:
160   /// The Module to write to bitcode.
161   const Module &M;
162 
163   /// Enumerates ids for all values in the module.
164   ValueEnumerator VE;
165 
166   /// Optional per-module index to write for ThinLTO.
167   const ModuleSummaryIndex *Index;
168 
169   /// Map that holds the correspondence between GUIDs in the summary index,
170   /// that came from indirect call profiles, and a value id generated by this
171   /// class to use in the VST and summary block records.
172   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
173 
174   /// Tracks the last value id recorded in the GUIDToValueMap.
175   unsigned GlobalValueId;
176 
177   /// Saves the offset of the VSTOffset record that must eventually be
178   /// backpatched with the offset of the actual VST.
179   uint64_t VSTOffsetPlaceholder = 0;
180 
181 public:
182   /// Constructs a ModuleBitcodeWriterBase object for the given Module,
183   /// writing to the provided \p Buffer.
184   ModuleBitcodeWriterBase(const Module &M, StringTableBuilder &StrtabBuilder,
185                           BitstreamWriter &Stream,
186                           bool ShouldPreserveUseListOrder,
187                           const ModuleSummaryIndex *Index)
188       : BitcodeWriterBase(Stream, StrtabBuilder), M(M),
189         VE(M, ShouldPreserveUseListOrder), Index(Index) {
190     // Assign ValueIds to any callee values in the index that came from
191     // indirect call profiles and were recorded as a GUID not a Value*
192     // (which would have been assigned an ID by the ValueEnumerator).
193     // The starting ValueId is just after the number of values in the
194     // ValueEnumerator, so that they can be emitted in the VST.
195     GlobalValueId = VE.getValues().size();
196     if (!Index)
197       return;
198     for (const auto &GUIDSummaryLists : *Index)
199       // Examine all summaries for this GUID.
200       for (auto &Summary : GUIDSummaryLists.second.SummaryList)
201         if (auto FS = dyn_cast<FunctionSummary>(Summary.get()))
202           // For each call in the function summary, see if the call
203           // is to a GUID (which means it is for an indirect call,
204           // otherwise we would have a Value for it). If so, synthesize
205           // a value id.
206           for (auto &CallEdge : FS->calls())
207             if (!CallEdge.first.haveGVs() || !CallEdge.first.getValue())
208               assignValueId(CallEdge.first.getGUID());
209   }
210 
211 protected:
212   void writePerModuleGlobalValueSummary();
213 
214 private:
215   void writePerModuleFunctionSummaryRecord(
216       SmallVector<uint64_t, 64> &NameVals, GlobalValueSummary *Summary,
217       unsigned ValueID, unsigned FSCallsAbbrev, unsigned FSCallsProfileAbbrev,
218       unsigned CallsiteAbbrev, unsigned AllocAbbrev, const Function &F);
219   void writeModuleLevelReferences(const GlobalVariable &V,
220                                   SmallVector<uint64_t, 64> &NameVals,
221                                   unsigned FSModRefsAbbrev,
222                                   unsigned FSModVTableRefsAbbrev);
223 
224   void assignValueId(GlobalValue::GUID ValGUID) {
225     GUIDToValueIdMap[ValGUID] = ++GlobalValueId;
226   }
227 
228   unsigned getValueId(GlobalValue::GUID ValGUID) {
229     const auto &VMI = GUIDToValueIdMap.find(ValGUID);
230     // Expect that any GUID value had a value Id assigned by an
231     // earlier call to assignValueId.
232     assert(VMI != GUIDToValueIdMap.end() &&
233            "GUID does not have assigned value Id");
234     return VMI->second;
235   }
236 
237   // Helper to get the valueId for the type of value recorded in VI.
238   unsigned getValueId(ValueInfo VI) {
239     if (!VI.haveGVs() || !VI.getValue())
240       return getValueId(VI.getGUID());
241     return VE.getValueID(VI.getValue());
242   }
243 
244   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
245 };
246 
247 /// Class to manage the bitcode writing for a module.
248 class ModuleBitcodeWriter : public ModuleBitcodeWriterBase {
249   /// Pointer to the buffer allocated by caller for bitcode writing.
250   const SmallVectorImpl<char> &Buffer;
251 
252   /// True if a module hash record should be written.
253   bool GenerateHash;
254 
255   /// If non-null, when GenerateHash is true, the resulting hash is written
256   /// into ModHash.
257   ModuleHash *ModHash;
258 
259   SHA1 Hasher;
260 
261   /// The start bit of the identification block.
262   uint64_t BitcodeStartBit;
263 
264 public:
265   /// Constructs a ModuleBitcodeWriter object for the given Module,
266   /// writing to the provided \p Buffer.
267   ModuleBitcodeWriter(const Module &M, SmallVectorImpl<char> &Buffer,
268                       StringTableBuilder &StrtabBuilder,
269                       BitstreamWriter &Stream, bool ShouldPreserveUseListOrder,
270                       const ModuleSummaryIndex *Index, bool GenerateHash,
271                       ModuleHash *ModHash = nullptr)
272       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
273                                 ShouldPreserveUseListOrder, Index),
274         Buffer(Buffer), GenerateHash(GenerateHash), ModHash(ModHash),
275         BitcodeStartBit(Stream.GetCurrentBitNo()) {}
276 
277   /// Emit the current module to the bitstream.
278   void write();
279 
280 private:
281   uint64_t bitcodeStartBit() { return BitcodeStartBit; }
282 
283   size_t addToStrtab(StringRef Str);
284 
285   void writeAttributeGroupTable();
286   void writeAttributeTable();
287   void writeTypeTable();
288   void writeComdats();
289   void writeValueSymbolTableForwardDecl();
290   void writeModuleInfo();
291   void writeValueAsMetadata(const ValueAsMetadata *MD,
292                             SmallVectorImpl<uint64_t> &Record);
293   void writeMDTuple(const MDTuple *N, SmallVectorImpl<uint64_t> &Record,
294                     unsigned Abbrev);
295   unsigned createDILocationAbbrev();
296   void writeDILocation(const DILocation *N, SmallVectorImpl<uint64_t> &Record,
297                        unsigned &Abbrev);
298   unsigned createGenericDINodeAbbrev();
299   void writeGenericDINode(const GenericDINode *N,
300                           SmallVectorImpl<uint64_t> &Record, unsigned &Abbrev);
301   void writeDISubrange(const DISubrange *N, SmallVectorImpl<uint64_t> &Record,
302                        unsigned Abbrev);
303   void writeDIGenericSubrange(const DIGenericSubrange *N,
304                               SmallVectorImpl<uint64_t> &Record,
305                               unsigned Abbrev);
306   void writeDIEnumerator(const DIEnumerator *N,
307                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
308   void writeDIBasicType(const DIBasicType *N, SmallVectorImpl<uint64_t> &Record,
309                         unsigned Abbrev);
310   void writeDIStringType(const DIStringType *N,
311                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
312   void writeDIDerivedType(const DIDerivedType *N,
313                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
314   void writeDICompositeType(const DICompositeType *N,
315                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
316   void writeDISubroutineType(const DISubroutineType *N,
317                              SmallVectorImpl<uint64_t> &Record,
318                              unsigned Abbrev);
319   void writeDIFile(const DIFile *N, SmallVectorImpl<uint64_t> &Record,
320                    unsigned Abbrev);
321   void writeDICompileUnit(const DICompileUnit *N,
322                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
323   void writeDISubprogram(const DISubprogram *N,
324                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
325   void writeDILexicalBlock(const DILexicalBlock *N,
326                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
327   void writeDILexicalBlockFile(const DILexicalBlockFile *N,
328                                SmallVectorImpl<uint64_t> &Record,
329                                unsigned Abbrev);
330   void writeDICommonBlock(const DICommonBlock *N,
331                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
332   void writeDINamespace(const DINamespace *N, SmallVectorImpl<uint64_t> &Record,
333                         unsigned Abbrev);
334   void writeDIMacro(const DIMacro *N, SmallVectorImpl<uint64_t> &Record,
335                     unsigned Abbrev);
336   void writeDIMacroFile(const DIMacroFile *N, SmallVectorImpl<uint64_t> &Record,
337                         unsigned Abbrev);
338   void writeDIArgList(const DIArgList *N, SmallVectorImpl<uint64_t> &Record,
339                       unsigned Abbrev);
340   void writeDIModule(const DIModule *N, SmallVectorImpl<uint64_t> &Record,
341                      unsigned Abbrev);
342   void writeDIAssignID(const DIAssignID *N, SmallVectorImpl<uint64_t> &Record,
343                        unsigned Abbrev);
344   void writeDITemplateTypeParameter(const DITemplateTypeParameter *N,
345                                     SmallVectorImpl<uint64_t> &Record,
346                                     unsigned Abbrev);
347   void writeDITemplateValueParameter(const DITemplateValueParameter *N,
348                                      SmallVectorImpl<uint64_t> &Record,
349                                      unsigned Abbrev);
350   void writeDIGlobalVariable(const DIGlobalVariable *N,
351                              SmallVectorImpl<uint64_t> &Record,
352                              unsigned Abbrev);
353   void writeDILocalVariable(const DILocalVariable *N,
354                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
355   void writeDILabel(const DILabel *N,
356                     SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
357   void writeDIExpression(const DIExpression *N,
358                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
359   void writeDIGlobalVariableExpression(const DIGlobalVariableExpression *N,
360                                        SmallVectorImpl<uint64_t> &Record,
361                                        unsigned Abbrev);
362   void writeDIObjCProperty(const DIObjCProperty *N,
363                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
364   void writeDIImportedEntity(const DIImportedEntity *N,
365                              SmallVectorImpl<uint64_t> &Record,
366                              unsigned Abbrev);
367   unsigned createNamedMetadataAbbrev();
368   void writeNamedMetadata(SmallVectorImpl<uint64_t> &Record);
369   unsigned createMetadataStringsAbbrev();
370   void writeMetadataStrings(ArrayRef<const Metadata *> Strings,
371                             SmallVectorImpl<uint64_t> &Record);
372   void writeMetadataRecords(ArrayRef<const Metadata *> MDs,
373                             SmallVectorImpl<uint64_t> &Record,
374                             std::vector<unsigned> *MDAbbrevs = nullptr,
375                             std::vector<uint64_t> *IndexPos = nullptr);
376   void writeModuleMetadata();
377   void writeFunctionMetadata(const Function &F);
378   void writeFunctionMetadataAttachment(const Function &F);
379   void pushGlobalMetadataAttachment(SmallVectorImpl<uint64_t> &Record,
380                                     const GlobalObject &GO);
381   void writeModuleMetadataKinds();
382   void writeOperandBundleTags();
383   void writeSyncScopeNames();
384   void writeConstants(unsigned FirstVal, unsigned LastVal, bool isGlobal);
385   void writeModuleConstants();
386   bool pushValueAndType(const Value *V, unsigned InstID,
387                         SmallVectorImpl<unsigned> &Vals);
388   void writeOperandBundles(const CallBase &CB, unsigned InstID);
389   void pushValue(const Value *V, unsigned InstID,
390                  SmallVectorImpl<unsigned> &Vals);
391   void pushValueSigned(const Value *V, unsigned InstID,
392                        SmallVectorImpl<uint64_t> &Vals);
393   void writeInstruction(const Instruction &I, unsigned InstID,
394                         SmallVectorImpl<unsigned> &Vals);
395   void writeFunctionLevelValueSymbolTable(const ValueSymbolTable &VST);
396   void writeGlobalValueSymbolTable(
397       DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
398   void writeUseList(UseListOrder &&Order);
399   void writeUseListBlock(const Function *F);
400   void
401   writeFunction(const Function &F,
402                 DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
403   void writeBlockInfo();
404   void writeModuleHash(size_t BlockStartPos);
405 
406   unsigned getEncodedSyncScopeID(SyncScope::ID SSID) {
407     return unsigned(SSID);
408   }
409 
410   unsigned getEncodedAlign(MaybeAlign Alignment) { return encode(Alignment); }
411 };
412 
413 /// Class to manage the bitcode writing for a combined index.
414 class IndexBitcodeWriter : public BitcodeWriterBase {
415   /// The combined index to write to bitcode.
416   const ModuleSummaryIndex &Index;
417 
418   /// When writing a subset of the index for distributed backends, client
419   /// provides a map of modules to the corresponding GUIDs/summaries to write.
420   const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex;
421 
422   /// Map that holds the correspondence between the GUID used in the combined
423   /// index and a value id generated by this class to use in references.
424   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
425 
426   // The sorted stack id indices actually used in the summary entries being
427   // written, which will be a subset of those in the full index in the case of
428   // distributed indexes.
429   std::vector<unsigned> StackIdIndices;
430 
431   /// Tracks the last value id recorded in the GUIDToValueMap.
432   unsigned GlobalValueId = 0;
433 
434   /// Tracks the assignment of module paths in the module path string table to
435   /// an id assigned for use in summary references to the module path.
436   DenseMap<StringRef, uint64_t> ModuleIdMap;
437 
438 public:
439   /// Constructs a IndexBitcodeWriter object for the given combined index,
440   /// writing to the provided \p Buffer. When writing a subset of the index
441   /// for a distributed backend, provide a \p ModuleToSummariesForIndex map.
442   IndexBitcodeWriter(BitstreamWriter &Stream, StringTableBuilder &StrtabBuilder,
443                      const ModuleSummaryIndex &Index,
444                      const std::map<std::string, GVSummaryMapTy>
445                          *ModuleToSummariesForIndex = nullptr)
446       : BitcodeWriterBase(Stream, StrtabBuilder), Index(Index),
447         ModuleToSummariesForIndex(ModuleToSummariesForIndex) {
448     // Assign unique value ids to all summaries to be written, for use
449     // in writing out the call graph edges. Save the mapping from GUID
450     // to the new global value id to use when writing those edges, which
451     // are currently saved in the index in terms of GUID.
452     forEachSummary([&](GVInfo I, bool IsAliasee) {
453       GUIDToValueIdMap[I.first] = ++GlobalValueId;
454       if (IsAliasee)
455         return;
456       auto *FS = dyn_cast<FunctionSummary>(I.second);
457       if (!FS)
458         return;
459       // Record all stack id indices actually used in the summary entries being
460       // written, so that we can compact them in the case of distributed ThinLTO
461       // indexes.
462       for (auto &CI : FS->callsites())
463         for (auto Idx : CI.StackIdIndices)
464           StackIdIndices.push_back(Idx);
465       for (auto &AI : FS->allocs())
466         for (auto &MIB : AI.MIBs)
467           for (auto Idx : MIB.StackIdIndices)
468             StackIdIndices.push_back(Idx);
469     });
470     llvm::sort(StackIdIndices);
471     StackIdIndices.erase(
472         std::unique(StackIdIndices.begin(), StackIdIndices.end()),
473         StackIdIndices.end());
474   }
475 
476   /// The below iterator returns the GUID and associated summary.
477   using GVInfo = std::pair<GlobalValue::GUID, GlobalValueSummary *>;
478 
479   /// Calls the callback for each value GUID and summary to be written to
480   /// bitcode. This hides the details of whether they are being pulled from the
481   /// entire index or just those in a provided ModuleToSummariesForIndex map.
482   template<typename Functor>
483   void forEachSummary(Functor Callback) {
484     if (ModuleToSummariesForIndex) {
485       for (auto &M : *ModuleToSummariesForIndex)
486         for (auto &Summary : M.second) {
487           Callback(Summary, false);
488           // Ensure aliasee is handled, e.g. for assigning a valueId,
489           // even if we are not importing the aliasee directly (the
490           // imported alias will contain a copy of aliasee).
491           if (auto *AS = dyn_cast<AliasSummary>(Summary.getSecond()))
492             Callback({AS->getAliaseeGUID(), &AS->getAliasee()}, true);
493         }
494     } else {
495       for (auto &Summaries : Index)
496         for (auto &Summary : Summaries.second.SummaryList)
497           Callback({Summaries.first, Summary.get()}, false);
498     }
499   }
500 
501   /// Calls the callback for each entry in the modulePaths StringMap that
502   /// should be written to the module path string table. This hides the details
503   /// of whether they are being pulled from the entire index or just those in a
504   /// provided ModuleToSummariesForIndex map.
505   template <typename Functor> void forEachModule(Functor Callback) {
506     if (ModuleToSummariesForIndex) {
507       for (const auto &M : *ModuleToSummariesForIndex) {
508         const auto &MPI = Index.modulePaths().find(M.first);
509         if (MPI == Index.modulePaths().end()) {
510           // This should only happen if the bitcode file was empty, in which
511           // case we shouldn't be importing (the ModuleToSummariesForIndex
512           // would only include the module we are writing and index for).
513           assert(ModuleToSummariesForIndex->size() == 1);
514           continue;
515         }
516         Callback(*MPI);
517       }
518     } else {
519       // Since StringMap iteration order isn't guaranteed, order by path string
520       // first.
521       // FIXME: Make this a vector of StringMapEntry instead to avoid the later
522       // map lookup.
523       std::vector<StringRef> ModulePaths;
524       for (auto &[ModPath, _] : Index.modulePaths())
525         ModulePaths.push_back(ModPath);
526       llvm::sort(ModulePaths.begin(), ModulePaths.end());
527       for (auto &ModPath : ModulePaths)
528         Callback(*Index.modulePaths().find(ModPath));
529     }
530   }
531 
532   /// Main entry point for writing a combined index to bitcode.
533   void write();
534 
535 private:
536   void writeModStrings();
537   void writeCombinedGlobalValueSummary();
538 
539   std::optional<unsigned> getValueId(GlobalValue::GUID ValGUID) {
540     auto VMI = GUIDToValueIdMap.find(ValGUID);
541     if (VMI == GUIDToValueIdMap.end())
542       return std::nullopt;
543     return VMI->second;
544   }
545 
546   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
547 };
548 
549 } // end anonymous namespace
550 
551 static unsigned getEncodedCastOpcode(unsigned Opcode) {
552   switch (Opcode) {
553   default: llvm_unreachable("Unknown cast instruction!");
554   case Instruction::Trunc   : return bitc::CAST_TRUNC;
555   case Instruction::ZExt    : return bitc::CAST_ZEXT;
556   case Instruction::SExt    : return bitc::CAST_SEXT;
557   case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
558   case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
559   case Instruction::UIToFP  : return bitc::CAST_UITOFP;
560   case Instruction::SIToFP  : return bitc::CAST_SITOFP;
561   case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
562   case Instruction::FPExt   : return bitc::CAST_FPEXT;
563   case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
564   case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
565   case Instruction::BitCast : return bitc::CAST_BITCAST;
566   case Instruction::AddrSpaceCast: return bitc::CAST_ADDRSPACECAST;
567   }
568 }
569 
570 static unsigned getEncodedUnaryOpcode(unsigned Opcode) {
571   switch (Opcode) {
572   default: llvm_unreachable("Unknown binary instruction!");
573   case Instruction::FNeg: return bitc::UNOP_FNEG;
574   }
575 }
576 
577 static unsigned getEncodedBinaryOpcode(unsigned Opcode) {
578   switch (Opcode) {
579   default: llvm_unreachable("Unknown binary instruction!");
580   case Instruction::Add:
581   case Instruction::FAdd: return bitc::BINOP_ADD;
582   case Instruction::Sub:
583   case Instruction::FSub: return bitc::BINOP_SUB;
584   case Instruction::Mul:
585   case Instruction::FMul: return bitc::BINOP_MUL;
586   case Instruction::UDiv: return bitc::BINOP_UDIV;
587   case Instruction::FDiv:
588   case Instruction::SDiv: return bitc::BINOP_SDIV;
589   case Instruction::URem: return bitc::BINOP_UREM;
590   case Instruction::FRem:
591   case Instruction::SRem: return bitc::BINOP_SREM;
592   case Instruction::Shl:  return bitc::BINOP_SHL;
593   case Instruction::LShr: return bitc::BINOP_LSHR;
594   case Instruction::AShr: return bitc::BINOP_ASHR;
595   case Instruction::And:  return bitc::BINOP_AND;
596   case Instruction::Or:   return bitc::BINOP_OR;
597   case Instruction::Xor:  return bitc::BINOP_XOR;
598   }
599 }
600 
601 static unsigned getEncodedRMWOperation(AtomicRMWInst::BinOp Op) {
602   switch (Op) {
603   default: llvm_unreachable("Unknown RMW operation!");
604   case AtomicRMWInst::Xchg: return bitc::RMW_XCHG;
605   case AtomicRMWInst::Add: return bitc::RMW_ADD;
606   case AtomicRMWInst::Sub: return bitc::RMW_SUB;
607   case AtomicRMWInst::And: return bitc::RMW_AND;
608   case AtomicRMWInst::Nand: return bitc::RMW_NAND;
609   case AtomicRMWInst::Or: return bitc::RMW_OR;
610   case AtomicRMWInst::Xor: return bitc::RMW_XOR;
611   case AtomicRMWInst::Max: return bitc::RMW_MAX;
612   case AtomicRMWInst::Min: return bitc::RMW_MIN;
613   case AtomicRMWInst::UMax: return bitc::RMW_UMAX;
614   case AtomicRMWInst::UMin: return bitc::RMW_UMIN;
615   case AtomicRMWInst::FAdd: return bitc::RMW_FADD;
616   case AtomicRMWInst::FSub: return bitc::RMW_FSUB;
617   case AtomicRMWInst::FMax: return bitc::RMW_FMAX;
618   case AtomicRMWInst::FMin: return bitc::RMW_FMIN;
619   case AtomicRMWInst::UIncWrap:
620     return bitc::RMW_UINC_WRAP;
621   case AtomicRMWInst::UDecWrap:
622     return bitc::RMW_UDEC_WRAP;
623   }
624 }
625 
626 static unsigned getEncodedOrdering(AtomicOrdering Ordering) {
627   switch (Ordering) {
628   case AtomicOrdering::NotAtomic: return bitc::ORDERING_NOTATOMIC;
629   case AtomicOrdering::Unordered: return bitc::ORDERING_UNORDERED;
630   case AtomicOrdering::Monotonic: return bitc::ORDERING_MONOTONIC;
631   case AtomicOrdering::Acquire: return bitc::ORDERING_ACQUIRE;
632   case AtomicOrdering::Release: return bitc::ORDERING_RELEASE;
633   case AtomicOrdering::AcquireRelease: return bitc::ORDERING_ACQREL;
634   case AtomicOrdering::SequentiallyConsistent: return bitc::ORDERING_SEQCST;
635   }
636   llvm_unreachable("Invalid ordering");
637 }
638 
639 static void writeStringRecord(BitstreamWriter &Stream, unsigned Code,
640                               StringRef Str, unsigned AbbrevToUse) {
641   SmallVector<unsigned, 64> Vals;
642 
643   // Code: [strchar x N]
644   for (char C : Str) {
645     if (AbbrevToUse && !BitCodeAbbrevOp::isChar6(C))
646       AbbrevToUse = 0;
647     Vals.push_back(C);
648   }
649 
650   // Emit the finished record.
651   Stream.EmitRecord(Code, Vals, AbbrevToUse);
652 }
653 
654 static uint64_t getAttrKindEncoding(Attribute::AttrKind Kind) {
655   switch (Kind) {
656   case Attribute::Alignment:
657     return bitc::ATTR_KIND_ALIGNMENT;
658   case Attribute::AllocAlign:
659     return bitc::ATTR_KIND_ALLOC_ALIGN;
660   case Attribute::AllocSize:
661     return bitc::ATTR_KIND_ALLOC_SIZE;
662   case Attribute::AlwaysInline:
663     return bitc::ATTR_KIND_ALWAYS_INLINE;
664   case Attribute::Builtin:
665     return bitc::ATTR_KIND_BUILTIN;
666   case Attribute::ByVal:
667     return bitc::ATTR_KIND_BY_VAL;
668   case Attribute::Convergent:
669     return bitc::ATTR_KIND_CONVERGENT;
670   case Attribute::InAlloca:
671     return bitc::ATTR_KIND_IN_ALLOCA;
672   case Attribute::Cold:
673     return bitc::ATTR_KIND_COLD;
674   case Attribute::DisableSanitizerInstrumentation:
675     return bitc::ATTR_KIND_DISABLE_SANITIZER_INSTRUMENTATION;
676   case Attribute::FnRetThunkExtern:
677     return bitc::ATTR_KIND_FNRETTHUNK_EXTERN;
678   case Attribute::Hot:
679     return bitc::ATTR_KIND_HOT;
680   case Attribute::ElementType:
681     return bitc::ATTR_KIND_ELEMENTTYPE;
682   case Attribute::InlineHint:
683     return bitc::ATTR_KIND_INLINE_HINT;
684   case Attribute::InReg:
685     return bitc::ATTR_KIND_IN_REG;
686   case Attribute::JumpTable:
687     return bitc::ATTR_KIND_JUMP_TABLE;
688   case Attribute::MinSize:
689     return bitc::ATTR_KIND_MIN_SIZE;
690   case Attribute::AllocatedPointer:
691     return bitc::ATTR_KIND_ALLOCATED_POINTER;
692   case Attribute::AllocKind:
693     return bitc::ATTR_KIND_ALLOC_KIND;
694   case Attribute::Memory:
695     return bitc::ATTR_KIND_MEMORY;
696   case Attribute::NoFPClass:
697     return bitc::ATTR_KIND_NOFPCLASS;
698   case Attribute::Naked:
699     return bitc::ATTR_KIND_NAKED;
700   case Attribute::Nest:
701     return bitc::ATTR_KIND_NEST;
702   case Attribute::NoAlias:
703     return bitc::ATTR_KIND_NO_ALIAS;
704   case Attribute::NoBuiltin:
705     return bitc::ATTR_KIND_NO_BUILTIN;
706   case Attribute::NoCallback:
707     return bitc::ATTR_KIND_NO_CALLBACK;
708   case Attribute::NoCapture:
709     return bitc::ATTR_KIND_NO_CAPTURE;
710   case Attribute::NoDuplicate:
711     return bitc::ATTR_KIND_NO_DUPLICATE;
712   case Attribute::NoFree:
713     return bitc::ATTR_KIND_NOFREE;
714   case Attribute::NoImplicitFloat:
715     return bitc::ATTR_KIND_NO_IMPLICIT_FLOAT;
716   case Attribute::NoInline:
717     return bitc::ATTR_KIND_NO_INLINE;
718   case Attribute::NoRecurse:
719     return bitc::ATTR_KIND_NO_RECURSE;
720   case Attribute::NoMerge:
721     return bitc::ATTR_KIND_NO_MERGE;
722   case Attribute::NonLazyBind:
723     return bitc::ATTR_KIND_NON_LAZY_BIND;
724   case Attribute::NonNull:
725     return bitc::ATTR_KIND_NON_NULL;
726   case Attribute::Dereferenceable:
727     return bitc::ATTR_KIND_DEREFERENCEABLE;
728   case Attribute::DereferenceableOrNull:
729     return bitc::ATTR_KIND_DEREFERENCEABLE_OR_NULL;
730   case Attribute::NoRedZone:
731     return bitc::ATTR_KIND_NO_RED_ZONE;
732   case Attribute::NoReturn:
733     return bitc::ATTR_KIND_NO_RETURN;
734   case Attribute::NoSync:
735     return bitc::ATTR_KIND_NOSYNC;
736   case Attribute::NoCfCheck:
737     return bitc::ATTR_KIND_NOCF_CHECK;
738   case Attribute::NoProfile:
739     return bitc::ATTR_KIND_NO_PROFILE;
740   case Attribute::SkipProfile:
741     return bitc::ATTR_KIND_SKIP_PROFILE;
742   case Attribute::NoUnwind:
743     return bitc::ATTR_KIND_NO_UNWIND;
744   case Attribute::NoSanitizeBounds:
745     return bitc::ATTR_KIND_NO_SANITIZE_BOUNDS;
746   case Attribute::NoSanitizeCoverage:
747     return bitc::ATTR_KIND_NO_SANITIZE_COVERAGE;
748   case Attribute::NullPointerIsValid:
749     return bitc::ATTR_KIND_NULL_POINTER_IS_VALID;
750   case Attribute::OptForFuzzing:
751     return bitc::ATTR_KIND_OPT_FOR_FUZZING;
752   case Attribute::OptimizeForSize:
753     return bitc::ATTR_KIND_OPTIMIZE_FOR_SIZE;
754   case Attribute::OptimizeNone:
755     return bitc::ATTR_KIND_OPTIMIZE_NONE;
756   case Attribute::ReadNone:
757     return bitc::ATTR_KIND_READ_NONE;
758   case Attribute::ReadOnly:
759     return bitc::ATTR_KIND_READ_ONLY;
760   case Attribute::Returned:
761     return bitc::ATTR_KIND_RETURNED;
762   case Attribute::ReturnsTwice:
763     return bitc::ATTR_KIND_RETURNS_TWICE;
764   case Attribute::SExt:
765     return bitc::ATTR_KIND_S_EXT;
766   case Attribute::Speculatable:
767     return bitc::ATTR_KIND_SPECULATABLE;
768   case Attribute::StackAlignment:
769     return bitc::ATTR_KIND_STACK_ALIGNMENT;
770   case Attribute::StackProtect:
771     return bitc::ATTR_KIND_STACK_PROTECT;
772   case Attribute::StackProtectReq:
773     return bitc::ATTR_KIND_STACK_PROTECT_REQ;
774   case Attribute::StackProtectStrong:
775     return bitc::ATTR_KIND_STACK_PROTECT_STRONG;
776   case Attribute::SafeStack:
777     return bitc::ATTR_KIND_SAFESTACK;
778   case Attribute::ShadowCallStack:
779     return bitc::ATTR_KIND_SHADOWCALLSTACK;
780   case Attribute::StrictFP:
781     return bitc::ATTR_KIND_STRICT_FP;
782   case Attribute::StructRet:
783     return bitc::ATTR_KIND_STRUCT_RET;
784   case Attribute::SanitizeAddress:
785     return bitc::ATTR_KIND_SANITIZE_ADDRESS;
786   case Attribute::SanitizeHWAddress:
787     return bitc::ATTR_KIND_SANITIZE_HWADDRESS;
788   case Attribute::SanitizeThread:
789     return bitc::ATTR_KIND_SANITIZE_THREAD;
790   case Attribute::SanitizeMemory:
791     return bitc::ATTR_KIND_SANITIZE_MEMORY;
792   case Attribute::SpeculativeLoadHardening:
793     return bitc::ATTR_KIND_SPECULATIVE_LOAD_HARDENING;
794   case Attribute::SwiftError:
795     return bitc::ATTR_KIND_SWIFT_ERROR;
796   case Attribute::SwiftSelf:
797     return bitc::ATTR_KIND_SWIFT_SELF;
798   case Attribute::SwiftAsync:
799     return bitc::ATTR_KIND_SWIFT_ASYNC;
800   case Attribute::UWTable:
801     return bitc::ATTR_KIND_UW_TABLE;
802   case Attribute::VScaleRange:
803     return bitc::ATTR_KIND_VSCALE_RANGE;
804   case Attribute::WillReturn:
805     return bitc::ATTR_KIND_WILLRETURN;
806   case Attribute::WriteOnly:
807     return bitc::ATTR_KIND_WRITEONLY;
808   case Attribute::ZExt:
809     return bitc::ATTR_KIND_Z_EXT;
810   case Attribute::ImmArg:
811     return bitc::ATTR_KIND_IMMARG;
812   case Attribute::SanitizeMemTag:
813     return bitc::ATTR_KIND_SANITIZE_MEMTAG;
814   case Attribute::Preallocated:
815     return bitc::ATTR_KIND_PREALLOCATED;
816   case Attribute::NoUndef:
817     return bitc::ATTR_KIND_NOUNDEF;
818   case Attribute::ByRef:
819     return bitc::ATTR_KIND_BYREF;
820   case Attribute::MustProgress:
821     return bitc::ATTR_KIND_MUSTPROGRESS;
822   case Attribute::PresplitCoroutine:
823     return bitc::ATTR_KIND_PRESPLIT_COROUTINE;
824   case Attribute::EndAttrKinds:
825     llvm_unreachable("Can not encode end-attribute kinds marker.");
826   case Attribute::None:
827     llvm_unreachable("Can not encode none-attribute.");
828   case Attribute::EmptyKey:
829   case Attribute::TombstoneKey:
830     llvm_unreachable("Trying to encode EmptyKey/TombstoneKey");
831   }
832 
833   llvm_unreachable("Trying to encode unknown attribute");
834 }
835 
836 void ModuleBitcodeWriter::writeAttributeGroupTable() {
837   const std::vector<ValueEnumerator::IndexAndAttrSet> &AttrGrps =
838       VE.getAttributeGroups();
839   if (AttrGrps.empty()) return;
840 
841   Stream.EnterSubblock(bitc::PARAMATTR_GROUP_BLOCK_ID, 3);
842 
843   SmallVector<uint64_t, 64> Record;
844   for (ValueEnumerator::IndexAndAttrSet Pair : AttrGrps) {
845     unsigned AttrListIndex = Pair.first;
846     AttributeSet AS = Pair.second;
847     Record.push_back(VE.getAttributeGroupID(Pair));
848     Record.push_back(AttrListIndex);
849 
850     for (Attribute Attr : AS) {
851       if (Attr.isEnumAttribute()) {
852         Record.push_back(0);
853         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
854       } else if (Attr.isIntAttribute()) {
855         Record.push_back(1);
856         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
857         Record.push_back(Attr.getValueAsInt());
858       } else if (Attr.isStringAttribute()) {
859         StringRef Kind = Attr.getKindAsString();
860         StringRef Val = Attr.getValueAsString();
861 
862         Record.push_back(Val.empty() ? 3 : 4);
863         Record.append(Kind.begin(), Kind.end());
864         Record.push_back(0);
865         if (!Val.empty()) {
866           Record.append(Val.begin(), Val.end());
867           Record.push_back(0);
868         }
869       } else {
870         assert(Attr.isTypeAttribute());
871         Type *Ty = Attr.getValueAsType();
872         Record.push_back(Ty ? 6 : 5);
873         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
874         if (Ty)
875           Record.push_back(VE.getTypeID(Attr.getValueAsType()));
876       }
877     }
878 
879     Stream.EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
880     Record.clear();
881   }
882 
883   Stream.ExitBlock();
884 }
885 
886 void ModuleBitcodeWriter::writeAttributeTable() {
887   const std::vector<AttributeList> &Attrs = VE.getAttributeLists();
888   if (Attrs.empty()) return;
889 
890   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
891 
892   SmallVector<uint64_t, 64> Record;
893   for (const AttributeList &AL : Attrs) {
894     for (unsigned i : AL.indexes()) {
895       AttributeSet AS = AL.getAttributes(i);
896       if (AS.hasAttributes())
897         Record.push_back(VE.getAttributeGroupID({i, AS}));
898     }
899 
900     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
901     Record.clear();
902   }
903 
904   Stream.ExitBlock();
905 }
906 
907 /// WriteTypeTable - Write out the type table for a module.
908 void ModuleBitcodeWriter::writeTypeTable() {
909   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
910 
911   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
912   SmallVector<uint64_t, 64> TypeVals;
913 
914   uint64_t NumBits = VE.computeBitsRequiredForTypeIndicies();
915 
916   // Abbrev for TYPE_CODE_OPAQUE_POINTER.
917   auto Abbv = std::make_shared<BitCodeAbbrev>();
918   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_OPAQUE_POINTER));
919   Abbv->Add(BitCodeAbbrevOp(0)); // Addrspace = 0
920   unsigned OpaquePtrAbbrev = Stream.EmitAbbrev(std::move(Abbv));
921 
922   // Abbrev for TYPE_CODE_FUNCTION.
923   Abbv = std::make_shared<BitCodeAbbrev>();
924   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
925   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
926   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
927   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
928   unsigned FunctionAbbrev = Stream.EmitAbbrev(std::move(Abbv));
929 
930   // Abbrev for TYPE_CODE_STRUCT_ANON.
931   Abbv = std::make_shared<BitCodeAbbrev>();
932   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
933   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
934   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
935   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
936   unsigned StructAnonAbbrev = Stream.EmitAbbrev(std::move(Abbv));
937 
938   // Abbrev for TYPE_CODE_STRUCT_NAME.
939   Abbv = std::make_shared<BitCodeAbbrev>();
940   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
941   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
942   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
943   unsigned StructNameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
944 
945   // Abbrev for TYPE_CODE_STRUCT_NAMED.
946   Abbv = std::make_shared<BitCodeAbbrev>();
947   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
948   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
949   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
950   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
951   unsigned StructNamedAbbrev = Stream.EmitAbbrev(std::move(Abbv));
952 
953   // Abbrev for TYPE_CODE_ARRAY.
954   Abbv = std::make_shared<BitCodeAbbrev>();
955   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
956   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
957   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
958   unsigned ArrayAbbrev = Stream.EmitAbbrev(std::move(Abbv));
959 
960   // Emit an entry count so the reader can reserve space.
961   TypeVals.push_back(TypeList.size());
962   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
963   TypeVals.clear();
964 
965   // Loop over all of the types, emitting each in turn.
966   for (Type *T : TypeList) {
967     int AbbrevToUse = 0;
968     unsigned Code = 0;
969 
970     switch (T->getTypeID()) {
971     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;      break;
972     case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;      break;
973     case Type::BFloatTyID:    Code = bitc::TYPE_CODE_BFLOAT;    break;
974     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;     break;
975     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE;    break;
976     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80;  break;
977     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128;     break;
978     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
979     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;     break;
980     case Type::MetadataTyID:  Code = bitc::TYPE_CODE_METADATA;  break;
981     case Type::X86_MMXTyID:   Code = bitc::TYPE_CODE_X86_MMX;   break;
982     case Type::X86_AMXTyID:   Code = bitc::TYPE_CODE_X86_AMX;   break;
983     case Type::TokenTyID:     Code = bitc::TYPE_CODE_TOKEN;     break;
984     case Type::IntegerTyID:
985       // INTEGER: [width]
986       Code = bitc::TYPE_CODE_INTEGER;
987       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
988       break;
989     case Type::PointerTyID: {
990       PointerType *PTy = cast<PointerType>(T);
991       unsigned AddressSpace = PTy->getAddressSpace();
992       // OPAQUE_POINTER: [address space]
993       Code = bitc::TYPE_CODE_OPAQUE_POINTER;
994       TypeVals.push_back(AddressSpace);
995       if (AddressSpace == 0)
996         AbbrevToUse = OpaquePtrAbbrev;
997       break;
998     }
999     case Type::FunctionTyID: {
1000       FunctionType *FT = cast<FunctionType>(T);
1001       // FUNCTION: [isvararg, retty, paramty x N]
1002       Code = bitc::TYPE_CODE_FUNCTION;
1003       TypeVals.push_back(FT->isVarArg());
1004       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
1005       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
1006         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
1007       AbbrevToUse = FunctionAbbrev;
1008       break;
1009     }
1010     case Type::StructTyID: {
1011       StructType *ST = cast<StructType>(T);
1012       // STRUCT: [ispacked, eltty x N]
1013       TypeVals.push_back(ST->isPacked());
1014       // Output all of the element types.
1015       for (Type *ET : ST->elements())
1016         TypeVals.push_back(VE.getTypeID(ET));
1017 
1018       if (ST->isLiteral()) {
1019         Code = bitc::TYPE_CODE_STRUCT_ANON;
1020         AbbrevToUse = StructAnonAbbrev;
1021       } else {
1022         if (ST->isOpaque()) {
1023           Code = bitc::TYPE_CODE_OPAQUE;
1024         } else {
1025           Code = bitc::TYPE_CODE_STRUCT_NAMED;
1026           AbbrevToUse = StructNamedAbbrev;
1027         }
1028 
1029         // Emit the name if it is present.
1030         if (!ST->getName().empty())
1031           writeStringRecord(Stream, bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
1032                             StructNameAbbrev);
1033       }
1034       break;
1035     }
1036     case Type::ArrayTyID: {
1037       ArrayType *AT = cast<ArrayType>(T);
1038       // ARRAY: [numelts, eltty]
1039       Code = bitc::TYPE_CODE_ARRAY;
1040       TypeVals.push_back(AT->getNumElements());
1041       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
1042       AbbrevToUse = ArrayAbbrev;
1043       break;
1044     }
1045     case Type::FixedVectorTyID:
1046     case Type::ScalableVectorTyID: {
1047       VectorType *VT = cast<VectorType>(T);
1048       // VECTOR [numelts, eltty] or
1049       //        [numelts, eltty, scalable]
1050       Code = bitc::TYPE_CODE_VECTOR;
1051       TypeVals.push_back(VT->getElementCount().getKnownMinValue());
1052       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
1053       if (isa<ScalableVectorType>(VT))
1054         TypeVals.push_back(true);
1055       break;
1056     }
1057     case Type::TargetExtTyID: {
1058       TargetExtType *TET = cast<TargetExtType>(T);
1059       Code = bitc::TYPE_CODE_TARGET_TYPE;
1060       writeStringRecord(Stream, bitc::TYPE_CODE_STRUCT_NAME, TET->getName(),
1061                         StructNameAbbrev);
1062       TypeVals.push_back(TET->getNumTypeParameters());
1063       for (Type *InnerTy : TET->type_params())
1064         TypeVals.push_back(VE.getTypeID(InnerTy));
1065       for (unsigned IntParam : TET->int_params())
1066         TypeVals.push_back(IntParam);
1067       break;
1068     }
1069     case Type::TypedPointerTyID:
1070       llvm_unreachable("Typed pointers cannot be added to IR modules");
1071     }
1072 
1073     // Emit the finished record.
1074     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
1075     TypeVals.clear();
1076   }
1077 
1078   Stream.ExitBlock();
1079 }
1080 
1081 static unsigned getEncodedLinkage(const GlobalValue::LinkageTypes Linkage) {
1082   switch (Linkage) {
1083   case GlobalValue::ExternalLinkage:
1084     return 0;
1085   case GlobalValue::WeakAnyLinkage:
1086     return 16;
1087   case GlobalValue::AppendingLinkage:
1088     return 2;
1089   case GlobalValue::InternalLinkage:
1090     return 3;
1091   case GlobalValue::LinkOnceAnyLinkage:
1092     return 18;
1093   case GlobalValue::ExternalWeakLinkage:
1094     return 7;
1095   case GlobalValue::CommonLinkage:
1096     return 8;
1097   case GlobalValue::PrivateLinkage:
1098     return 9;
1099   case GlobalValue::WeakODRLinkage:
1100     return 17;
1101   case GlobalValue::LinkOnceODRLinkage:
1102     return 19;
1103   case GlobalValue::AvailableExternallyLinkage:
1104     return 12;
1105   }
1106   llvm_unreachable("Invalid linkage");
1107 }
1108 
1109 static unsigned getEncodedLinkage(const GlobalValue &GV) {
1110   return getEncodedLinkage(GV.getLinkage());
1111 }
1112 
1113 static uint64_t getEncodedFFlags(FunctionSummary::FFlags Flags) {
1114   uint64_t RawFlags = 0;
1115   RawFlags |= Flags.ReadNone;
1116   RawFlags |= (Flags.ReadOnly << 1);
1117   RawFlags |= (Flags.NoRecurse << 2);
1118   RawFlags |= (Flags.ReturnDoesNotAlias << 3);
1119   RawFlags |= (Flags.NoInline << 4);
1120   RawFlags |= (Flags.AlwaysInline << 5);
1121   RawFlags |= (Flags.NoUnwind << 6);
1122   RawFlags |= (Flags.MayThrow << 7);
1123   RawFlags |= (Flags.HasUnknownCall << 8);
1124   RawFlags |= (Flags.MustBeUnreachable << 9);
1125   return RawFlags;
1126 }
1127 
1128 // Decode the flags for GlobalValue in the summary. See getDecodedGVSummaryFlags
1129 // in BitcodeReader.cpp.
1130 static uint64_t getEncodedGVSummaryFlags(GlobalValueSummary::GVFlags Flags) {
1131   uint64_t RawFlags = 0;
1132 
1133   RawFlags |= Flags.NotEligibleToImport; // bool
1134   RawFlags |= (Flags.Live << 1);
1135   RawFlags |= (Flags.DSOLocal << 2);
1136   RawFlags |= (Flags.CanAutoHide << 3);
1137 
1138   // Linkage don't need to be remapped at that time for the summary. Any future
1139   // change to the getEncodedLinkage() function will need to be taken into
1140   // account here as well.
1141   RawFlags = (RawFlags << 4) | Flags.Linkage; // 4 bits
1142 
1143   RawFlags |= (Flags.Visibility << 8); // 2 bits
1144 
1145   return RawFlags;
1146 }
1147 
1148 static uint64_t getEncodedGVarFlags(GlobalVarSummary::GVarFlags Flags) {
1149   uint64_t RawFlags = Flags.MaybeReadOnly | (Flags.MaybeWriteOnly << 1) |
1150                       (Flags.Constant << 2) | Flags.VCallVisibility << 3;
1151   return RawFlags;
1152 }
1153 
1154 static unsigned getEncodedVisibility(const GlobalValue &GV) {
1155   switch (GV.getVisibility()) {
1156   case GlobalValue::DefaultVisibility:   return 0;
1157   case GlobalValue::HiddenVisibility:    return 1;
1158   case GlobalValue::ProtectedVisibility: return 2;
1159   }
1160   llvm_unreachable("Invalid visibility");
1161 }
1162 
1163 static unsigned getEncodedDLLStorageClass(const GlobalValue &GV) {
1164   switch (GV.getDLLStorageClass()) {
1165   case GlobalValue::DefaultStorageClass:   return 0;
1166   case GlobalValue::DLLImportStorageClass: return 1;
1167   case GlobalValue::DLLExportStorageClass: return 2;
1168   }
1169   llvm_unreachable("Invalid DLL storage class");
1170 }
1171 
1172 static unsigned getEncodedThreadLocalMode(const GlobalValue &GV) {
1173   switch (GV.getThreadLocalMode()) {
1174     case GlobalVariable::NotThreadLocal:         return 0;
1175     case GlobalVariable::GeneralDynamicTLSModel: return 1;
1176     case GlobalVariable::LocalDynamicTLSModel:   return 2;
1177     case GlobalVariable::InitialExecTLSModel:    return 3;
1178     case GlobalVariable::LocalExecTLSModel:      return 4;
1179   }
1180   llvm_unreachable("Invalid TLS model");
1181 }
1182 
1183 static unsigned getEncodedComdatSelectionKind(const Comdat &C) {
1184   switch (C.getSelectionKind()) {
1185   case Comdat::Any:
1186     return bitc::COMDAT_SELECTION_KIND_ANY;
1187   case Comdat::ExactMatch:
1188     return bitc::COMDAT_SELECTION_KIND_EXACT_MATCH;
1189   case Comdat::Largest:
1190     return bitc::COMDAT_SELECTION_KIND_LARGEST;
1191   case Comdat::NoDeduplicate:
1192     return bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES;
1193   case Comdat::SameSize:
1194     return bitc::COMDAT_SELECTION_KIND_SAME_SIZE;
1195   }
1196   llvm_unreachable("Invalid selection kind");
1197 }
1198 
1199 static unsigned getEncodedUnnamedAddr(const GlobalValue &GV) {
1200   switch (GV.getUnnamedAddr()) {
1201   case GlobalValue::UnnamedAddr::None:   return 0;
1202   case GlobalValue::UnnamedAddr::Local:  return 2;
1203   case GlobalValue::UnnamedAddr::Global: return 1;
1204   }
1205   llvm_unreachable("Invalid unnamed_addr");
1206 }
1207 
1208 size_t ModuleBitcodeWriter::addToStrtab(StringRef Str) {
1209   if (GenerateHash)
1210     Hasher.update(Str);
1211   return StrtabBuilder.add(Str);
1212 }
1213 
1214 void ModuleBitcodeWriter::writeComdats() {
1215   SmallVector<unsigned, 64> Vals;
1216   for (const Comdat *C : VE.getComdats()) {
1217     // COMDAT: [strtab offset, strtab size, selection_kind]
1218     Vals.push_back(addToStrtab(C->getName()));
1219     Vals.push_back(C->getName().size());
1220     Vals.push_back(getEncodedComdatSelectionKind(*C));
1221     Stream.EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
1222     Vals.clear();
1223   }
1224 }
1225 
1226 /// Write a record that will eventually hold the word offset of the
1227 /// module-level VST. For now the offset is 0, which will be backpatched
1228 /// after the real VST is written. Saves the bit offset to backpatch.
1229 void ModuleBitcodeWriter::writeValueSymbolTableForwardDecl() {
1230   // Write a placeholder value in for the offset of the real VST,
1231   // which is written after the function blocks so that it can include
1232   // the offset of each function. The placeholder offset will be
1233   // updated when the real VST is written.
1234   auto Abbv = std::make_shared<BitCodeAbbrev>();
1235   Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_VSTOFFSET));
1236   // Blocks are 32-bit aligned, so we can use a 32-bit word offset to
1237   // hold the real VST offset. Must use fixed instead of VBR as we don't
1238   // know how many VBR chunks to reserve ahead of time.
1239   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
1240   unsigned VSTOffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1241 
1242   // Emit the placeholder
1243   uint64_t Vals[] = {bitc::MODULE_CODE_VSTOFFSET, 0};
1244   Stream.EmitRecordWithAbbrev(VSTOffsetAbbrev, Vals);
1245 
1246   // Compute and save the bit offset to the placeholder, which will be
1247   // patched when the real VST is written. We can simply subtract the 32-bit
1248   // fixed size from the current bit number to get the location to backpatch.
1249   VSTOffsetPlaceholder = Stream.GetCurrentBitNo() - 32;
1250 }
1251 
1252 enum StringEncoding { SE_Char6, SE_Fixed7, SE_Fixed8 };
1253 
1254 /// Determine the encoding to use for the given string name and length.
1255 static StringEncoding getStringEncoding(StringRef Str) {
1256   bool isChar6 = true;
1257   for (char C : Str) {
1258     if (isChar6)
1259       isChar6 = BitCodeAbbrevOp::isChar6(C);
1260     if ((unsigned char)C & 128)
1261       // don't bother scanning the rest.
1262       return SE_Fixed8;
1263   }
1264   if (isChar6)
1265     return SE_Char6;
1266   return SE_Fixed7;
1267 }
1268 
1269 static_assert(sizeof(GlobalValue::SanitizerMetadata) <= sizeof(unsigned),
1270               "Sanitizer Metadata is too large for naive serialization.");
1271 static unsigned
1272 serializeSanitizerMetadata(const GlobalValue::SanitizerMetadata &Meta) {
1273   return Meta.NoAddress | (Meta.NoHWAddress << 1) |
1274          (Meta.Memtag << 2) | (Meta.IsDynInit << 3);
1275 }
1276 
1277 /// Emit top-level description of module, including target triple, inline asm,
1278 /// descriptors for global variables, and function prototype info.
1279 /// Returns the bit offset to backpatch with the location of the real VST.
1280 void ModuleBitcodeWriter::writeModuleInfo() {
1281   // Emit various pieces of data attached to a module.
1282   if (!M.getTargetTriple().empty())
1283     writeStringRecord(Stream, bitc::MODULE_CODE_TRIPLE, M.getTargetTriple(),
1284                       0 /*TODO*/);
1285   const std::string &DL = M.getDataLayoutStr();
1286   if (!DL.empty())
1287     writeStringRecord(Stream, bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/);
1288   if (!M.getModuleInlineAsm().empty())
1289     writeStringRecord(Stream, bitc::MODULE_CODE_ASM, M.getModuleInlineAsm(),
1290                       0 /*TODO*/);
1291 
1292   // Emit information about sections and GC, computing how many there are. Also
1293   // compute the maximum alignment value.
1294   std::map<std::string, unsigned> SectionMap;
1295   std::map<std::string, unsigned> GCMap;
1296   MaybeAlign MaxAlignment;
1297   unsigned MaxGlobalType = 0;
1298   const auto UpdateMaxAlignment = [&MaxAlignment](const MaybeAlign A) {
1299     if (A)
1300       MaxAlignment = !MaxAlignment ? *A : std::max(*MaxAlignment, *A);
1301   };
1302   for (const GlobalVariable &GV : M.globals()) {
1303     UpdateMaxAlignment(GV.getAlign());
1304     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getValueType()));
1305     if (GV.hasSection()) {
1306       // Give section names unique ID's.
1307       unsigned &Entry = SectionMap[std::string(GV.getSection())];
1308       if (!Entry) {
1309         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
1310                           0 /*TODO*/);
1311         Entry = SectionMap.size();
1312       }
1313     }
1314   }
1315   for (const Function &F : M) {
1316     UpdateMaxAlignment(F.getAlign());
1317     if (F.hasSection()) {
1318       // Give section names unique ID's.
1319       unsigned &Entry = SectionMap[std::string(F.getSection())];
1320       if (!Entry) {
1321         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
1322                           0 /*TODO*/);
1323         Entry = SectionMap.size();
1324       }
1325     }
1326     if (F.hasGC()) {
1327       // Same for GC names.
1328       unsigned &Entry = GCMap[F.getGC()];
1329       if (!Entry) {
1330         writeStringRecord(Stream, bitc::MODULE_CODE_GCNAME, F.getGC(),
1331                           0 /*TODO*/);
1332         Entry = GCMap.size();
1333       }
1334     }
1335   }
1336 
1337   // Emit abbrev for globals, now that we know # sections and max alignment.
1338   unsigned SimpleGVarAbbrev = 0;
1339   if (!M.global_empty()) {
1340     // Add an abbrev for common globals with no visibility or thread localness.
1341     auto Abbv = std::make_shared<BitCodeAbbrev>();
1342     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
1343     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1344     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1345     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1346                               Log2_32_Ceil(MaxGlobalType+1)));
1347     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddrSpace << 2
1348                                                            //| explicitType << 1
1349                                                            //| constant
1350     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Initializer.
1351     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // Linkage.
1352     if (!MaxAlignment)                                     // Alignment.
1353       Abbv->Add(BitCodeAbbrevOp(0));
1354     else {
1355       unsigned MaxEncAlignment = getEncodedAlign(MaxAlignment);
1356       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1357                                Log2_32_Ceil(MaxEncAlignment+1)));
1358     }
1359     if (SectionMap.empty())                                    // Section.
1360       Abbv->Add(BitCodeAbbrevOp(0));
1361     else
1362       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1363                                Log2_32_Ceil(SectionMap.size()+1)));
1364     // Don't bother emitting vis + thread local.
1365     SimpleGVarAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1366   }
1367 
1368   SmallVector<unsigned, 64> Vals;
1369   // Emit the module's source file name.
1370   {
1371     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
1372     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
1373     if (Bits == SE_Char6)
1374       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
1375     else if (Bits == SE_Fixed7)
1376       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
1377 
1378     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
1379     auto Abbv = std::make_shared<BitCodeAbbrev>();
1380     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
1381     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1382     Abbv->Add(AbbrevOpToUse);
1383     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1384 
1385     for (const auto P : M.getSourceFileName())
1386       Vals.push_back((unsigned char)P);
1387 
1388     // Emit the finished record.
1389     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
1390     Vals.clear();
1391   }
1392 
1393   // Emit the global variable information.
1394   for (const GlobalVariable &GV : M.globals()) {
1395     unsigned AbbrevToUse = 0;
1396 
1397     // GLOBALVAR: [strtab offset, strtab size, type, isconst, initid,
1398     //             linkage, alignment, section, visibility, threadlocal,
1399     //             unnamed_addr, externally_initialized, dllstorageclass,
1400     //             comdat, attributes, DSO_Local, GlobalSanitizer]
1401     Vals.push_back(addToStrtab(GV.getName()));
1402     Vals.push_back(GV.getName().size());
1403     Vals.push_back(VE.getTypeID(GV.getValueType()));
1404     Vals.push_back(GV.getType()->getAddressSpace() << 2 | 2 | GV.isConstant());
1405     Vals.push_back(GV.isDeclaration() ? 0 :
1406                    (VE.getValueID(GV.getInitializer()) + 1));
1407     Vals.push_back(getEncodedLinkage(GV));
1408     Vals.push_back(getEncodedAlign(GV.getAlign()));
1409     Vals.push_back(GV.hasSection() ? SectionMap[std::string(GV.getSection())]
1410                                    : 0);
1411     if (GV.isThreadLocal() ||
1412         GV.getVisibility() != GlobalValue::DefaultVisibility ||
1413         GV.getUnnamedAddr() != GlobalValue::UnnamedAddr::None ||
1414         GV.isExternallyInitialized() ||
1415         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
1416         GV.hasComdat() || GV.hasAttributes() || GV.isDSOLocal() ||
1417         GV.hasPartition() || GV.hasSanitizerMetadata()) {
1418       Vals.push_back(getEncodedVisibility(GV));
1419       Vals.push_back(getEncodedThreadLocalMode(GV));
1420       Vals.push_back(getEncodedUnnamedAddr(GV));
1421       Vals.push_back(GV.isExternallyInitialized());
1422       Vals.push_back(getEncodedDLLStorageClass(GV));
1423       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
1424 
1425       auto AL = GV.getAttributesAsList(AttributeList::FunctionIndex);
1426       Vals.push_back(VE.getAttributeListID(AL));
1427 
1428       Vals.push_back(GV.isDSOLocal());
1429       Vals.push_back(addToStrtab(GV.getPartition()));
1430       Vals.push_back(GV.getPartition().size());
1431 
1432       Vals.push_back((GV.hasSanitizerMetadata() ? serializeSanitizerMetadata(
1433                                                       GV.getSanitizerMetadata())
1434                                                 : 0));
1435     } else {
1436       AbbrevToUse = SimpleGVarAbbrev;
1437     }
1438 
1439     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
1440     Vals.clear();
1441   }
1442 
1443   // Emit the function proto information.
1444   for (const Function &F : M) {
1445     // FUNCTION:  [strtab offset, strtab size, type, callingconv, isproto,
1446     //             linkage, paramattrs, alignment, section, visibility, gc,
1447     //             unnamed_addr, prologuedata, dllstorageclass, comdat,
1448     //             prefixdata, personalityfn, DSO_Local, addrspace]
1449     Vals.push_back(addToStrtab(F.getName()));
1450     Vals.push_back(F.getName().size());
1451     Vals.push_back(VE.getTypeID(F.getFunctionType()));
1452     Vals.push_back(F.getCallingConv());
1453     Vals.push_back(F.isDeclaration());
1454     Vals.push_back(getEncodedLinkage(F));
1455     Vals.push_back(VE.getAttributeListID(F.getAttributes()));
1456     Vals.push_back(getEncodedAlign(F.getAlign()));
1457     Vals.push_back(F.hasSection() ? SectionMap[std::string(F.getSection())]
1458                                   : 0);
1459     Vals.push_back(getEncodedVisibility(F));
1460     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
1461     Vals.push_back(getEncodedUnnamedAddr(F));
1462     Vals.push_back(F.hasPrologueData() ? (VE.getValueID(F.getPrologueData()) + 1)
1463                                        : 0);
1464     Vals.push_back(getEncodedDLLStorageClass(F));
1465     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
1466     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
1467                                      : 0);
1468     Vals.push_back(
1469         F.hasPersonalityFn() ? (VE.getValueID(F.getPersonalityFn()) + 1) : 0);
1470 
1471     Vals.push_back(F.isDSOLocal());
1472     Vals.push_back(F.getAddressSpace());
1473     Vals.push_back(addToStrtab(F.getPartition()));
1474     Vals.push_back(F.getPartition().size());
1475 
1476     unsigned AbbrevToUse = 0;
1477     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
1478     Vals.clear();
1479   }
1480 
1481   // Emit the alias information.
1482   for (const GlobalAlias &A : M.aliases()) {
1483     // ALIAS: [strtab offset, strtab size, alias type, aliasee val#, linkage,
1484     //         visibility, dllstorageclass, threadlocal, unnamed_addr,
1485     //         DSO_Local]
1486     Vals.push_back(addToStrtab(A.getName()));
1487     Vals.push_back(A.getName().size());
1488     Vals.push_back(VE.getTypeID(A.getValueType()));
1489     Vals.push_back(A.getType()->getAddressSpace());
1490     Vals.push_back(VE.getValueID(A.getAliasee()));
1491     Vals.push_back(getEncodedLinkage(A));
1492     Vals.push_back(getEncodedVisibility(A));
1493     Vals.push_back(getEncodedDLLStorageClass(A));
1494     Vals.push_back(getEncodedThreadLocalMode(A));
1495     Vals.push_back(getEncodedUnnamedAddr(A));
1496     Vals.push_back(A.isDSOLocal());
1497     Vals.push_back(addToStrtab(A.getPartition()));
1498     Vals.push_back(A.getPartition().size());
1499 
1500     unsigned AbbrevToUse = 0;
1501     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
1502     Vals.clear();
1503   }
1504 
1505   // Emit the ifunc information.
1506   for (const GlobalIFunc &I : M.ifuncs()) {
1507     // IFUNC: [strtab offset, strtab size, ifunc type, address space, resolver
1508     //         val#, linkage, visibility, DSO_Local]
1509     Vals.push_back(addToStrtab(I.getName()));
1510     Vals.push_back(I.getName().size());
1511     Vals.push_back(VE.getTypeID(I.getValueType()));
1512     Vals.push_back(I.getType()->getAddressSpace());
1513     Vals.push_back(VE.getValueID(I.getResolver()));
1514     Vals.push_back(getEncodedLinkage(I));
1515     Vals.push_back(getEncodedVisibility(I));
1516     Vals.push_back(I.isDSOLocal());
1517     Vals.push_back(addToStrtab(I.getPartition()));
1518     Vals.push_back(I.getPartition().size());
1519     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
1520     Vals.clear();
1521   }
1522 
1523   writeValueSymbolTableForwardDecl();
1524 }
1525 
1526 static uint64_t getOptimizationFlags(const Value *V) {
1527   uint64_t Flags = 0;
1528 
1529   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
1530     if (OBO->hasNoSignedWrap())
1531       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
1532     if (OBO->hasNoUnsignedWrap())
1533       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
1534   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
1535     if (PEO->isExact())
1536       Flags |= 1 << bitc::PEO_EXACT;
1537   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
1538     if (FPMO->hasAllowReassoc())
1539       Flags |= bitc::AllowReassoc;
1540     if (FPMO->hasNoNaNs())
1541       Flags |= bitc::NoNaNs;
1542     if (FPMO->hasNoInfs())
1543       Flags |= bitc::NoInfs;
1544     if (FPMO->hasNoSignedZeros())
1545       Flags |= bitc::NoSignedZeros;
1546     if (FPMO->hasAllowReciprocal())
1547       Flags |= bitc::AllowReciprocal;
1548     if (FPMO->hasAllowContract())
1549       Flags |= bitc::AllowContract;
1550     if (FPMO->hasApproxFunc())
1551       Flags |= bitc::ApproxFunc;
1552   }
1553 
1554   return Flags;
1555 }
1556 
1557 void ModuleBitcodeWriter::writeValueAsMetadata(
1558     const ValueAsMetadata *MD, SmallVectorImpl<uint64_t> &Record) {
1559   // Mimic an MDNode with a value as one operand.
1560   Value *V = MD->getValue();
1561   Record.push_back(VE.getTypeID(V->getType()));
1562   Record.push_back(VE.getValueID(V));
1563   Stream.EmitRecord(bitc::METADATA_VALUE, Record, 0);
1564   Record.clear();
1565 }
1566 
1567 void ModuleBitcodeWriter::writeMDTuple(const MDTuple *N,
1568                                        SmallVectorImpl<uint64_t> &Record,
1569                                        unsigned Abbrev) {
1570   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
1571     Metadata *MD = N->getOperand(i);
1572     assert(!(MD && isa<LocalAsMetadata>(MD)) &&
1573            "Unexpected function-local metadata");
1574     Record.push_back(VE.getMetadataOrNullID(MD));
1575   }
1576   Stream.EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
1577                                     : bitc::METADATA_NODE,
1578                     Record, Abbrev);
1579   Record.clear();
1580 }
1581 
1582 unsigned ModuleBitcodeWriter::createDILocationAbbrev() {
1583   // Assume the column is usually under 128, and always output the inlined-at
1584   // location (it's never more expensive than building an array size 1).
1585   auto Abbv = std::make_shared<BitCodeAbbrev>();
1586   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
1587   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1588   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1589   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1590   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1591   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1592   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1593   return Stream.EmitAbbrev(std::move(Abbv));
1594 }
1595 
1596 void ModuleBitcodeWriter::writeDILocation(const DILocation *N,
1597                                           SmallVectorImpl<uint64_t> &Record,
1598                                           unsigned &Abbrev) {
1599   if (!Abbrev)
1600     Abbrev = createDILocationAbbrev();
1601 
1602   Record.push_back(N->isDistinct());
1603   Record.push_back(N->getLine());
1604   Record.push_back(N->getColumn());
1605   Record.push_back(VE.getMetadataID(N->getScope()));
1606   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
1607   Record.push_back(N->isImplicitCode());
1608 
1609   Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
1610   Record.clear();
1611 }
1612 
1613 unsigned ModuleBitcodeWriter::createGenericDINodeAbbrev() {
1614   // Assume the column is usually under 128, and always output the inlined-at
1615   // location (it's never more expensive than building an array size 1).
1616   auto Abbv = std::make_shared<BitCodeAbbrev>();
1617   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
1618   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1619   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1620   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1621   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1622   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1623   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1624   return Stream.EmitAbbrev(std::move(Abbv));
1625 }
1626 
1627 void ModuleBitcodeWriter::writeGenericDINode(const GenericDINode *N,
1628                                              SmallVectorImpl<uint64_t> &Record,
1629                                              unsigned &Abbrev) {
1630   if (!Abbrev)
1631     Abbrev = createGenericDINodeAbbrev();
1632 
1633   Record.push_back(N->isDistinct());
1634   Record.push_back(N->getTag());
1635   Record.push_back(0); // Per-tag version field; unused for now.
1636 
1637   for (auto &I : N->operands())
1638     Record.push_back(VE.getMetadataOrNullID(I));
1639 
1640   Stream.EmitRecord(bitc::METADATA_GENERIC_DEBUG, Record, Abbrev);
1641   Record.clear();
1642 }
1643 
1644 void ModuleBitcodeWriter::writeDISubrange(const DISubrange *N,
1645                                           SmallVectorImpl<uint64_t> &Record,
1646                                           unsigned Abbrev) {
1647   const uint64_t Version = 2 << 1;
1648   Record.push_back((uint64_t)N->isDistinct() | Version);
1649   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1650   Record.push_back(VE.getMetadataOrNullID(N->getRawLowerBound()));
1651   Record.push_back(VE.getMetadataOrNullID(N->getRawUpperBound()));
1652   Record.push_back(VE.getMetadataOrNullID(N->getRawStride()));
1653 
1654   Stream.EmitRecord(bitc::METADATA_SUBRANGE, Record, Abbrev);
1655   Record.clear();
1656 }
1657 
1658 void ModuleBitcodeWriter::writeDIGenericSubrange(
1659     const DIGenericSubrange *N, SmallVectorImpl<uint64_t> &Record,
1660     unsigned Abbrev) {
1661   Record.push_back((uint64_t)N->isDistinct());
1662   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1663   Record.push_back(VE.getMetadataOrNullID(N->getRawLowerBound()));
1664   Record.push_back(VE.getMetadataOrNullID(N->getRawUpperBound()));
1665   Record.push_back(VE.getMetadataOrNullID(N->getRawStride()));
1666 
1667   Stream.EmitRecord(bitc::METADATA_GENERIC_SUBRANGE, Record, Abbrev);
1668   Record.clear();
1669 }
1670 
1671 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
1672   if ((int64_t)V >= 0)
1673     Vals.push_back(V << 1);
1674   else
1675     Vals.push_back((-V << 1) | 1);
1676 }
1677 
1678 static void emitWideAPInt(SmallVectorImpl<uint64_t> &Vals, const APInt &A) {
1679   // We have an arbitrary precision integer value to write whose
1680   // bit width is > 64. However, in canonical unsigned integer
1681   // format it is likely that the high bits are going to be zero.
1682   // So, we only write the number of active words.
1683   unsigned NumWords = A.getActiveWords();
1684   const uint64_t *RawData = A.getRawData();
1685   for (unsigned i = 0; i < NumWords; i++)
1686     emitSignedInt64(Vals, RawData[i]);
1687 }
1688 
1689 void ModuleBitcodeWriter::writeDIEnumerator(const DIEnumerator *N,
1690                                             SmallVectorImpl<uint64_t> &Record,
1691                                             unsigned Abbrev) {
1692   const uint64_t IsBigInt = 1 << 2;
1693   Record.push_back(IsBigInt | (N->isUnsigned() << 1) | N->isDistinct());
1694   Record.push_back(N->getValue().getBitWidth());
1695   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1696   emitWideAPInt(Record, N->getValue());
1697 
1698   Stream.EmitRecord(bitc::METADATA_ENUMERATOR, Record, Abbrev);
1699   Record.clear();
1700 }
1701 
1702 void ModuleBitcodeWriter::writeDIBasicType(const DIBasicType *N,
1703                                            SmallVectorImpl<uint64_t> &Record,
1704                                            unsigned Abbrev) {
1705   Record.push_back(N->isDistinct());
1706   Record.push_back(N->getTag());
1707   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1708   Record.push_back(N->getSizeInBits());
1709   Record.push_back(N->getAlignInBits());
1710   Record.push_back(N->getEncoding());
1711   Record.push_back(N->getFlags());
1712 
1713   Stream.EmitRecord(bitc::METADATA_BASIC_TYPE, Record, Abbrev);
1714   Record.clear();
1715 }
1716 
1717 void ModuleBitcodeWriter::writeDIStringType(const DIStringType *N,
1718                                             SmallVectorImpl<uint64_t> &Record,
1719                                             unsigned Abbrev) {
1720   Record.push_back(N->isDistinct());
1721   Record.push_back(N->getTag());
1722   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1723   Record.push_back(VE.getMetadataOrNullID(N->getStringLength()));
1724   Record.push_back(VE.getMetadataOrNullID(N->getStringLengthExp()));
1725   Record.push_back(VE.getMetadataOrNullID(N->getStringLocationExp()));
1726   Record.push_back(N->getSizeInBits());
1727   Record.push_back(N->getAlignInBits());
1728   Record.push_back(N->getEncoding());
1729 
1730   Stream.EmitRecord(bitc::METADATA_STRING_TYPE, Record, Abbrev);
1731   Record.clear();
1732 }
1733 
1734 void ModuleBitcodeWriter::writeDIDerivedType(const DIDerivedType *N,
1735                                              SmallVectorImpl<uint64_t> &Record,
1736                                              unsigned Abbrev) {
1737   Record.push_back(N->isDistinct());
1738   Record.push_back(N->getTag());
1739   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1740   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1741   Record.push_back(N->getLine());
1742   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1743   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1744   Record.push_back(N->getSizeInBits());
1745   Record.push_back(N->getAlignInBits());
1746   Record.push_back(N->getOffsetInBits());
1747   Record.push_back(N->getFlags());
1748   Record.push_back(VE.getMetadataOrNullID(N->getExtraData()));
1749 
1750   // DWARF address space is encoded as N->getDWARFAddressSpace() + 1. 0 means
1751   // that there is no DWARF address space associated with DIDerivedType.
1752   if (const auto &DWARFAddressSpace = N->getDWARFAddressSpace())
1753     Record.push_back(*DWARFAddressSpace + 1);
1754   else
1755     Record.push_back(0);
1756 
1757   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1758 
1759   Stream.EmitRecord(bitc::METADATA_DERIVED_TYPE, Record, Abbrev);
1760   Record.clear();
1761 }
1762 
1763 void ModuleBitcodeWriter::writeDICompositeType(
1764     const DICompositeType *N, SmallVectorImpl<uint64_t> &Record,
1765     unsigned Abbrev) {
1766   const unsigned IsNotUsedInOldTypeRef = 0x2;
1767   Record.push_back(IsNotUsedInOldTypeRef | (unsigned)N->isDistinct());
1768   Record.push_back(N->getTag());
1769   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1770   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1771   Record.push_back(N->getLine());
1772   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1773   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1774   Record.push_back(N->getSizeInBits());
1775   Record.push_back(N->getAlignInBits());
1776   Record.push_back(N->getOffsetInBits());
1777   Record.push_back(N->getFlags());
1778   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1779   Record.push_back(N->getRuntimeLang());
1780   Record.push_back(VE.getMetadataOrNullID(N->getVTableHolder()));
1781   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1782   Record.push_back(VE.getMetadataOrNullID(N->getRawIdentifier()));
1783   Record.push_back(VE.getMetadataOrNullID(N->getDiscriminator()));
1784   Record.push_back(VE.getMetadataOrNullID(N->getRawDataLocation()));
1785   Record.push_back(VE.getMetadataOrNullID(N->getRawAssociated()));
1786   Record.push_back(VE.getMetadataOrNullID(N->getRawAllocated()));
1787   Record.push_back(VE.getMetadataOrNullID(N->getRawRank()));
1788   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1789 
1790   Stream.EmitRecord(bitc::METADATA_COMPOSITE_TYPE, Record, Abbrev);
1791   Record.clear();
1792 }
1793 
1794 void ModuleBitcodeWriter::writeDISubroutineType(
1795     const DISubroutineType *N, SmallVectorImpl<uint64_t> &Record,
1796     unsigned Abbrev) {
1797   const unsigned HasNoOldTypeRefs = 0x2;
1798   Record.push_back(HasNoOldTypeRefs | (unsigned)N->isDistinct());
1799   Record.push_back(N->getFlags());
1800   Record.push_back(VE.getMetadataOrNullID(N->getTypeArray().get()));
1801   Record.push_back(N->getCC());
1802 
1803   Stream.EmitRecord(bitc::METADATA_SUBROUTINE_TYPE, Record, Abbrev);
1804   Record.clear();
1805 }
1806 
1807 void ModuleBitcodeWriter::writeDIFile(const DIFile *N,
1808                                       SmallVectorImpl<uint64_t> &Record,
1809                                       unsigned Abbrev) {
1810   Record.push_back(N->isDistinct());
1811   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
1812   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
1813   if (N->getRawChecksum()) {
1814     Record.push_back(N->getRawChecksum()->Kind);
1815     Record.push_back(VE.getMetadataOrNullID(N->getRawChecksum()->Value));
1816   } else {
1817     // Maintain backwards compatibility with the old internal representation of
1818     // CSK_None in ChecksumKind by writing nulls here when Checksum is None.
1819     Record.push_back(0);
1820     Record.push_back(VE.getMetadataOrNullID(nullptr));
1821   }
1822   auto Source = N->getRawSource();
1823   if (Source)
1824     Record.push_back(VE.getMetadataOrNullID(Source));
1825 
1826   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
1827   Record.clear();
1828 }
1829 
1830 void ModuleBitcodeWriter::writeDICompileUnit(const DICompileUnit *N,
1831                                              SmallVectorImpl<uint64_t> &Record,
1832                                              unsigned Abbrev) {
1833   assert(N->isDistinct() && "Expected distinct compile units");
1834   Record.push_back(/* IsDistinct */ true);
1835   Record.push_back(N->getSourceLanguage());
1836   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1837   Record.push_back(VE.getMetadataOrNullID(N->getRawProducer()));
1838   Record.push_back(N->isOptimized());
1839   Record.push_back(VE.getMetadataOrNullID(N->getRawFlags()));
1840   Record.push_back(N->getRuntimeVersion());
1841   Record.push_back(VE.getMetadataOrNullID(N->getRawSplitDebugFilename()));
1842   Record.push_back(N->getEmissionKind());
1843   Record.push_back(VE.getMetadataOrNullID(N->getEnumTypes().get()));
1844   Record.push_back(VE.getMetadataOrNullID(N->getRetainedTypes().get()));
1845   Record.push_back(/* subprograms */ 0);
1846   Record.push_back(VE.getMetadataOrNullID(N->getGlobalVariables().get()));
1847   Record.push_back(VE.getMetadataOrNullID(N->getImportedEntities().get()));
1848   Record.push_back(N->getDWOId());
1849   Record.push_back(VE.getMetadataOrNullID(N->getMacros().get()));
1850   Record.push_back(N->getSplitDebugInlining());
1851   Record.push_back(N->getDebugInfoForProfiling());
1852   Record.push_back((unsigned)N->getNameTableKind());
1853   Record.push_back(N->getRangesBaseAddress());
1854   Record.push_back(VE.getMetadataOrNullID(N->getRawSysRoot()));
1855   Record.push_back(VE.getMetadataOrNullID(N->getRawSDK()));
1856 
1857   Stream.EmitRecord(bitc::METADATA_COMPILE_UNIT, Record, Abbrev);
1858   Record.clear();
1859 }
1860 
1861 void ModuleBitcodeWriter::writeDISubprogram(const DISubprogram *N,
1862                                             SmallVectorImpl<uint64_t> &Record,
1863                                             unsigned Abbrev) {
1864   const uint64_t HasUnitFlag = 1 << 1;
1865   const uint64_t HasSPFlagsFlag = 1 << 2;
1866   Record.push_back(uint64_t(N->isDistinct()) | HasUnitFlag | HasSPFlagsFlag);
1867   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1868   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1869   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1870   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1871   Record.push_back(N->getLine());
1872   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1873   Record.push_back(N->getScopeLine());
1874   Record.push_back(VE.getMetadataOrNullID(N->getContainingType()));
1875   Record.push_back(N->getSPFlags());
1876   Record.push_back(N->getVirtualIndex());
1877   Record.push_back(N->getFlags());
1878   Record.push_back(VE.getMetadataOrNullID(N->getRawUnit()));
1879   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1880   Record.push_back(VE.getMetadataOrNullID(N->getDeclaration()));
1881   Record.push_back(VE.getMetadataOrNullID(N->getRetainedNodes().get()));
1882   Record.push_back(N->getThisAdjustment());
1883   Record.push_back(VE.getMetadataOrNullID(N->getThrownTypes().get()));
1884   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1885   Record.push_back(VE.getMetadataOrNullID(N->getRawTargetFuncName()));
1886 
1887   Stream.EmitRecord(bitc::METADATA_SUBPROGRAM, Record, Abbrev);
1888   Record.clear();
1889 }
1890 
1891 void ModuleBitcodeWriter::writeDILexicalBlock(const DILexicalBlock *N,
1892                                               SmallVectorImpl<uint64_t> &Record,
1893                                               unsigned Abbrev) {
1894   Record.push_back(N->isDistinct());
1895   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1896   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1897   Record.push_back(N->getLine());
1898   Record.push_back(N->getColumn());
1899 
1900   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK, Record, Abbrev);
1901   Record.clear();
1902 }
1903 
1904 void ModuleBitcodeWriter::writeDILexicalBlockFile(
1905     const DILexicalBlockFile *N, SmallVectorImpl<uint64_t> &Record,
1906     unsigned Abbrev) {
1907   Record.push_back(N->isDistinct());
1908   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1909   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1910   Record.push_back(N->getDiscriminator());
1911 
1912   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK_FILE, Record, Abbrev);
1913   Record.clear();
1914 }
1915 
1916 void ModuleBitcodeWriter::writeDICommonBlock(const DICommonBlock *N,
1917                                              SmallVectorImpl<uint64_t> &Record,
1918                                              unsigned Abbrev) {
1919   Record.push_back(N->isDistinct());
1920   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1921   Record.push_back(VE.getMetadataOrNullID(N->getDecl()));
1922   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1923   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1924   Record.push_back(N->getLineNo());
1925 
1926   Stream.EmitRecord(bitc::METADATA_COMMON_BLOCK, Record, Abbrev);
1927   Record.clear();
1928 }
1929 
1930 void ModuleBitcodeWriter::writeDINamespace(const DINamespace *N,
1931                                            SmallVectorImpl<uint64_t> &Record,
1932                                            unsigned Abbrev) {
1933   Record.push_back(N->isDistinct() | N->getExportSymbols() << 1);
1934   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1935   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1936 
1937   Stream.EmitRecord(bitc::METADATA_NAMESPACE, Record, Abbrev);
1938   Record.clear();
1939 }
1940 
1941 void ModuleBitcodeWriter::writeDIMacro(const DIMacro *N,
1942                                        SmallVectorImpl<uint64_t> &Record,
1943                                        unsigned Abbrev) {
1944   Record.push_back(N->isDistinct());
1945   Record.push_back(N->getMacinfoType());
1946   Record.push_back(N->getLine());
1947   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1948   Record.push_back(VE.getMetadataOrNullID(N->getRawValue()));
1949 
1950   Stream.EmitRecord(bitc::METADATA_MACRO, Record, Abbrev);
1951   Record.clear();
1952 }
1953 
1954 void ModuleBitcodeWriter::writeDIMacroFile(const DIMacroFile *N,
1955                                            SmallVectorImpl<uint64_t> &Record,
1956                                            unsigned Abbrev) {
1957   Record.push_back(N->isDistinct());
1958   Record.push_back(N->getMacinfoType());
1959   Record.push_back(N->getLine());
1960   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1961   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1962 
1963   Stream.EmitRecord(bitc::METADATA_MACRO_FILE, Record, Abbrev);
1964   Record.clear();
1965 }
1966 
1967 void ModuleBitcodeWriter::writeDIArgList(const DIArgList *N,
1968                                          SmallVectorImpl<uint64_t> &Record,
1969                                          unsigned Abbrev) {
1970   Record.reserve(N->getArgs().size());
1971   for (ValueAsMetadata *MD : N->getArgs())
1972     Record.push_back(VE.getMetadataID(MD));
1973 
1974   Stream.EmitRecord(bitc::METADATA_ARG_LIST, Record, Abbrev);
1975   Record.clear();
1976 }
1977 
1978 void ModuleBitcodeWriter::writeDIModule(const DIModule *N,
1979                                         SmallVectorImpl<uint64_t> &Record,
1980                                         unsigned Abbrev) {
1981   Record.push_back(N->isDistinct());
1982   for (auto &I : N->operands())
1983     Record.push_back(VE.getMetadataOrNullID(I));
1984   Record.push_back(N->getLineNo());
1985   Record.push_back(N->getIsDecl());
1986 
1987   Stream.EmitRecord(bitc::METADATA_MODULE, Record, Abbrev);
1988   Record.clear();
1989 }
1990 
1991 void ModuleBitcodeWriter::writeDIAssignID(const DIAssignID *N,
1992                                           SmallVectorImpl<uint64_t> &Record,
1993                                           unsigned Abbrev) {
1994   // There are no arguments for this metadata type.
1995   Record.push_back(N->isDistinct());
1996   Stream.EmitRecord(bitc::METADATA_ASSIGN_ID, Record, Abbrev);
1997   Record.clear();
1998 }
1999 
2000 void ModuleBitcodeWriter::writeDITemplateTypeParameter(
2001     const DITemplateTypeParameter *N, SmallVectorImpl<uint64_t> &Record,
2002     unsigned Abbrev) {
2003   Record.push_back(N->isDistinct());
2004   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2005   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2006   Record.push_back(N->isDefault());
2007 
2008   Stream.EmitRecord(bitc::METADATA_TEMPLATE_TYPE, Record, Abbrev);
2009   Record.clear();
2010 }
2011 
2012 void ModuleBitcodeWriter::writeDITemplateValueParameter(
2013     const DITemplateValueParameter *N, SmallVectorImpl<uint64_t> &Record,
2014     unsigned Abbrev) {
2015   Record.push_back(N->isDistinct());
2016   Record.push_back(N->getTag());
2017   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2018   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2019   Record.push_back(N->isDefault());
2020   Record.push_back(VE.getMetadataOrNullID(N->getValue()));
2021 
2022   Stream.EmitRecord(bitc::METADATA_TEMPLATE_VALUE, Record, Abbrev);
2023   Record.clear();
2024 }
2025 
2026 void ModuleBitcodeWriter::writeDIGlobalVariable(
2027     const DIGlobalVariable *N, SmallVectorImpl<uint64_t> &Record,
2028     unsigned Abbrev) {
2029   const uint64_t Version = 2 << 1;
2030   Record.push_back((uint64_t)N->isDistinct() | Version);
2031   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2032   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2033   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
2034   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2035   Record.push_back(N->getLine());
2036   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2037   Record.push_back(N->isLocalToUnit());
2038   Record.push_back(N->isDefinition());
2039   Record.push_back(VE.getMetadataOrNullID(N->getStaticDataMemberDeclaration()));
2040   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams()));
2041   Record.push_back(N->getAlignInBits());
2042   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
2043 
2044   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR, Record, Abbrev);
2045   Record.clear();
2046 }
2047 
2048 void ModuleBitcodeWriter::writeDILocalVariable(
2049     const DILocalVariable *N, SmallVectorImpl<uint64_t> &Record,
2050     unsigned Abbrev) {
2051   // In order to support all possible bitcode formats in BitcodeReader we need
2052   // to distinguish the following cases:
2053   // 1) Record has no artificial tag (Record[1]),
2054   //   has no obsolete inlinedAt field (Record[9]).
2055   //   In this case Record size will be 8, HasAlignment flag is false.
2056   // 2) Record has artificial tag (Record[1]),
2057   //   has no obsolete inlignedAt field (Record[9]).
2058   //   In this case Record size will be 9, HasAlignment flag is false.
2059   // 3) Record has both artificial tag (Record[1]) and
2060   //   obsolete inlignedAt field (Record[9]).
2061   //   In this case Record size will be 10, HasAlignment flag is false.
2062   // 4) Record has neither artificial tag, nor inlignedAt field, but
2063   //   HasAlignment flag is true and Record[8] contains alignment value.
2064   const uint64_t HasAlignmentFlag = 1 << 1;
2065   Record.push_back((uint64_t)N->isDistinct() | HasAlignmentFlag);
2066   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2067   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2068   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2069   Record.push_back(N->getLine());
2070   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2071   Record.push_back(N->getArg());
2072   Record.push_back(N->getFlags());
2073   Record.push_back(N->getAlignInBits());
2074   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
2075 
2076   Stream.EmitRecord(bitc::METADATA_LOCAL_VAR, Record, Abbrev);
2077   Record.clear();
2078 }
2079 
2080 void ModuleBitcodeWriter::writeDILabel(
2081     const DILabel *N, SmallVectorImpl<uint64_t> &Record,
2082     unsigned Abbrev) {
2083   Record.push_back((uint64_t)N->isDistinct());
2084   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2085   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2086   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2087   Record.push_back(N->getLine());
2088 
2089   Stream.EmitRecord(bitc::METADATA_LABEL, Record, Abbrev);
2090   Record.clear();
2091 }
2092 
2093 void ModuleBitcodeWriter::writeDIExpression(const DIExpression *N,
2094                                             SmallVectorImpl<uint64_t> &Record,
2095                                             unsigned Abbrev) {
2096   Record.reserve(N->getElements().size() + 1);
2097   const uint64_t Version = 3 << 1;
2098   Record.push_back((uint64_t)N->isDistinct() | Version);
2099   Record.append(N->elements_begin(), N->elements_end());
2100 
2101   Stream.EmitRecord(bitc::METADATA_EXPRESSION, Record, Abbrev);
2102   Record.clear();
2103 }
2104 
2105 void ModuleBitcodeWriter::writeDIGlobalVariableExpression(
2106     const DIGlobalVariableExpression *N, SmallVectorImpl<uint64_t> &Record,
2107     unsigned Abbrev) {
2108   Record.push_back(N->isDistinct());
2109   Record.push_back(VE.getMetadataOrNullID(N->getVariable()));
2110   Record.push_back(VE.getMetadataOrNullID(N->getExpression()));
2111 
2112   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR_EXPR, Record, Abbrev);
2113   Record.clear();
2114 }
2115 
2116 void ModuleBitcodeWriter::writeDIObjCProperty(const DIObjCProperty *N,
2117                                               SmallVectorImpl<uint64_t> &Record,
2118                                               unsigned Abbrev) {
2119   Record.push_back(N->isDistinct());
2120   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2121   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2122   Record.push_back(N->getLine());
2123   Record.push_back(VE.getMetadataOrNullID(N->getRawSetterName()));
2124   Record.push_back(VE.getMetadataOrNullID(N->getRawGetterName()));
2125   Record.push_back(N->getAttributes());
2126   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2127 
2128   Stream.EmitRecord(bitc::METADATA_OBJC_PROPERTY, Record, Abbrev);
2129   Record.clear();
2130 }
2131 
2132 void ModuleBitcodeWriter::writeDIImportedEntity(
2133     const DIImportedEntity *N, SmallVectorImpl<uint64_t> &Record,
2134     unsigned Abbrev) {
2135   Record.push_back(N->isDistinct());
2136   Record.push_back(N->getTag());
2137   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2138   Record.push_back(VE.getMetadataOrNullID(N->getEntity()));
2139   Record.push_back(N->getLine());
2140   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2141   Record.push_back(VE.getMetadataOrNullID(N->getRawFile()));
2142   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
2143 
2144   Stream.EmitRecord(bitc::METADATA_IMPORTED_ENTITY, Record, Abbrev);
2145   Record.clear();
2146 }
2147 
2148 unsigned ModuleBitcodeWriter::createNamedMetadataAbbrev() {
2149   auto Abbv = std::make_shared<BitCodeAbbrev>();
2150   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
2151   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2152   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2153   return Stream.EmitAbbrev(std::move(Abbv));
2154 }
2155 
2156 void ModuleBitcodeWriter::writeNamedMetadata(
2157     SmallVectorImpl<uint64_t> &Record) {
2158   if (M.named_metadata_empty())
2159     return;
2160 
2161   unsigned Abbrev = createNamedMetadataAbbrev();
2162   for (const NamedMDNode &NMD : M.named_metadata()) {
2163     // Write name.
2164     StringRef Str = NMD.getName();
2165     Record.append(Str.bytes_begin(), Str.bytes_end());
2166     Stream.EmitRecord(bitc::METADATA_NAME, Record, Abbrev);
2167     Record.clear();
2168 
2169     // Write named metadata operands.
2170     for (const MDNode *N : NMD.operands())
2171       Record.push_back(VE.getMetadataID(N));
2172     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
2173     Record.clear();
2174   }
2175 }
2176 
2177 unsigned ModuleBitcodeWriter::createMetadataStringsAbbrev() {
2178   auto Abbv = std::make_shared<BitCodeAbbrev>();
2179   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRINGS));
2180   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // # of strings
2181   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // offset to chars
2182   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
2183   return Stream.EmitAbbrev(std::move(Abbv));
2184 }
2185 
2186 /// Write out a record for MDString.
2187 ///
2188 /// All the metadata strings in a metadata block are emitted in a single
2189 /// record.  The sizes and strings themselves are shoved into a blob.
2190 void ModuleBitcodeWriter::writeMetadataStrings(
2191     ArrayRef<const Metadata *> Strings, SmallVectorImpl<uint64_t> &Record) {
2192   if (Strings.empty())
2193     return;
2194 
2195   // Start the record with the number of strings.
2196   Record.push_back(bitc::METADATA_STRINGS);
2197   Record.push_back(Strings.size());
2198 
2199   // Emit the sizes of the strings in the blob.
2200   SmallString<256> Blob;
2201   {
2202     BitstreamWriter W(Blob);
2203     for (const Metadata *MD : Strings)
2204       W.EmitVBR(cast<MDString>(MD)->getLength(), 6);
2205     W.FlushToWord();
2206   }
2207 
2208   // Add the offset to the strings to the record.
2209   Record.push_back(Blob.size());
2210 
2211   // Add the strings to the blob.
2212   for (const Metadata *MD : Strings)
2213     Blob.append(cast<MDString>(MD)->getString());
2214 
2215   // Emit the final record.
2216   Stream.EmitRecordWithBlob(createMetadataStringsAbbrev(), Record, Blob);
2217   Record.clear();
2218 }
2219 
2220 // Generates an enum to use as an index in the Abbrev array of Metadata record.
2221 enum MetadataAbbrev : unsigned {
2222 #define HANDLE_MDNODE_LEAF(CLASS) CLASS##AbbrevID,
2223 #include "llvm/IR/Metadata.def"
2224   LastPlusOne
2225 };
2226 
2227 void ModuleBitcodeWriter::writeMetadataRecords(
2228     ArrayRef<const Metadata *> MDs, SmallVectorImpl<uint64_t> &Record,
2229     std::vector<unsigned> *MDAbbrevs, std::vector<uint64_t> *IndexPos) {
2230   if (MDs.empty())
2231     return;
2232 
2233   // Initialize MDNode abbreviations.
2234 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
2235 #include "llvm/IR/Metadata.def"
2236 
2237   for (const Metadata *MD : MDs) {
2238     if (IndexPos)
2239       IndexPos->push_back(Stream.GetCurrentBitNo());
2240     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
2241       assert(N->isResolved() && "Expected forward references to be resolved");
2242 
2243       switch (N->getMetadataID()) {
2244       default:
2245         llvm_unreachable("Invalid MDNode subclass");
2246 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
2247   case Metadata::CLASS##Kind:                                                  \
2248     if (MDAbbrevs)                                                             \
2249       write##CLASS(cast<CLASS>(N), Record,                                     \
2250                    (*MDAbbrevs)[MetadataAbbrev::CLASS##AbbrevID]);             \
2251     else                                                                       \
2252       write##CLASS(cast<CLASS>(N), Record, CLASS##Abbrev);                     \
2253     continue;
2254 #include "llvm/IR/Metadata.def"
2255       }
2256     }
2257     writeValueAsMetadata(cast<ValueAsMetadata>(MD), Record);
2258   }
2259 }
2260 
2261 void ModuleBitcodeWriter::writeModuleMetadata() {
2262   if (!VE.hasMDs() && M.named_metadata_empty())
2263     return;
2264 
2265   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 4);
2266   SmallVector<uint64_t, 64> Record;
2267 
2268   // Emit all abbrevs upfront, so that the reader can jump in the middle of the
2269   // block and load any metadata.
2270   std::vector<unsigned> MDAbbrevs;
2271 
2272   MDAbbrevs.resize(MetadataAbbrev::LastPlusOne);
2273   MDAbbrevs[MetadataAbbrev::DILocationAbbrevID] = createDILocationAbbrev();
2274   MDAbbrevs[MetadataAbbrev::GenericDINodeAbbrevID] =
2275       createGenericDINodeAbbrev();
2276 
2277   auto Abbv = std::make_shared<BitCodeAbbrev>();
2278   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX_OFFSET));
2279   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2280   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2281   unsigned OffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2282 
2283   Abbv = std::make_shared<BitCodeAbbrev>();
2284   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX));
2285   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2286   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2287   unsigned IndexAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2288 
2289   // Emit MDStrings together upfront.
2290   writeMetadataStrings(VE.getMDStrings(), Record);
2291 
2292   // We only emit an index for the metadata record if we have more than a given
2293   // (naive) threshold of metadatas, otherwise it is not worth it.
2294   if (VE.getNonMDStrings().size() > IndexThreshold) {
2295     // Write a placeholder value in for the offset of the metadata index,
2296     // which is written after the records, so that it can include
2297     // the offset of each entry. The placeholder offset will be
2298     // updated after all records are emitted.
2299     uint64_t Vals[] = {0, 0};
2300     Stream.EmitRecord(bitc::METADATA_INDEX_OFFSET, Vals, OffsetAbbrev);
2301   }
2302 
2303   // Compute and save the bit offset to the current position, which will be
2304   // patched when we emit the index later. We can simply subtract the 64-bit
2305   // fixed size from the current bit number to get the location to backpatch.
2306   uint64_t IndexOffsetRecordBitPos = Stream.GetCurrentBitNo();
2307 
2308   // This index will contain the bitpos for each individual record.
2309   std::vector<uint64_t> IndexPos;
2310   IndexPos.reserve(VE.getNonMDStrings().size());
2311 
2312   // Write all the records
2313   writeMetadataRecords(VE.getNonMDStrings(), Record, &MDAbbrevs, &IndexPos);
2314 
2315   if (VE.getNonMDStrings().size() > IndexThreshold) {
2316     // Now that we have emitted all the records we will emit the index. But
2317     // first
2318     // backpatch the forward reference so that the reader can skip the records
2319     // efficiently.
2320     Stream.BackpatchWord64(IndexOffsetRecordBitPos - 64,
2321                            Stream.GetCurrentBitNo() - IndexOffsetRecordBitPos);
2322 
2323     // Delta encode the index.
2324     uint64_t PreviousValue = IndexOffsetRecordBitPos;
2325     for (auto &Elt : IndexPos) {
2326       auto EltDelta = Elt - PreviousValue;
2327       PreviousValue = Elt;
2328       Elt = EltDelta;
2329     }
2330     // Emit the index record.
2331     Stream.EmitRecord(bitc::METADATA_INDEX, IndexPos, IndexAbbrev);
2332     IndexPos.clear();
2333   }
2334 
2335   // Write the named metadata now.
2336   writeNamedMetadata(Record);
2337 
2338   auto AddDeclAttachedMetadata = [&](const GlobalObject &GO) {
2339     SmallVector<uint64_t, 4> Record;
2340     Record.push_back(VE.getValueID(&GO));
2341     pushGlobalMetadataAttachment(Record, GO);
2342     Stream.EmitRecord(bitc::METADATA_GLOBAL_DECL_ATTACHMENT, Record);
2343   };
2344   for (const Function &F : M)
2345     if (F.isDeclaration() && F.hasMetadata())
2346       AddDeclAttachedMetadata(F);
2347   // FIXME: Only store metadata for declarations here, and move data for global
2348   // variable definitions to a separate block (PR28134).
2349   for (const GlobalVariable &GV : M.globals())
2350     if (GV.hasMetadata())
2351       AddDeclAttachedMetadata(GV);
2352 
2353   Stream.ExitBlock();
2354 }
2355 
2356 void ModuleBitcodeWriter::writeFunctionMetadata(const Function &F) {
2357   if (!VE.hasMDs())
2358     return;
2359 
2360   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
2361   SmallVector<uint64_t, 64> Record;
2362   writeMetadataStrings(VE.getMDStrings(), Record);
2363   writeMetadataRecords(VE.getNonMDStrings(), Record);
2364   Stream.ExitBlock();
2365 }
2366 
2367 void ModuleBitcodeWriter::pushGlobalMetadataAttachment(
2368     SmallVectorImpl<uint64_t> &Record, const GlobalObject &GO) {
2369   // [n x [id, mdnode]]
2370   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2371   GO.getAllMetadata(MDs);
2372   for (const auto &I : MDs) {
2373     Record.push_back(I.first);
2374     Record.push_back(VE.getMetadataID(I.second));
2375   }
2376 }
2377 
2378 void ModuleBitcodeWriter::writeFunctionMetadataAttachment(const Function &F) {
2379   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
2380 
2381   SmallVector<uint64_t, 64> Record;
2382 
2383   if (F.hasMetadata()) {
2384     pushGlobalMetadataAttachment(Record, F);
2385     Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2386     Record.clear();
2387   }
2388 
2389   // Write metadata attachments
2390   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
2391   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2392   for (const BasicBlock &BB : F)
2393     for (const Instruction &I : BB) {
2394       MDs.clear();
2395       I.getAllMetadataOtherThanDebugLoc(MDs);
2396 
2397       // If no metadata, ignore instruction.
2398       if (MDs.empty()) continue;
2399 
2400       Record.push_back(VE.getInstructionID(&I));
2401 
2402       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
2403         Record.push_back(MDs[i].first);
2404         Record.push_back(VE.getMetadataID(MDs[i].second));
2405       }
2406       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2407       Record.clear();
2408     }
2409 
2410   Stream.ExitBlock();
2411 }
2412 
2413 void ModuleBitcodeWriter::writeModuleMetadataKinds() {
2414   SmallVector<uint64_t, 64> Record;
2415 
2416   // Write metadata kinds
2417   // METADATA_KIND - [n x [id, name]]
2418   SmallVector<StringRef, 8> Names;
2419   M.getMDKindNames(Names);
2420 
2421   if (Names.empty()) return;
2422 
2423   Stream.EnterSubblock(bitc::METADATA_KIND_BLOCK_ID, 3);
2424 
2425   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
2426     Record.push_back(MDKindID);
2427     StringRef KName = Names[MDKindID];
2428     Record.append(KName.begin(), KName.end());
2429 
2430     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
2431     Record.clear();
2432   }
2433 
2434   Stream.ExitBlock();
2435 }
2436 
2437 void ModuleBitcodeWriter::writeOperandBundleTags() {
2438   // Write metadata kinds
2439   //
2440   // OPERAND_BUNDLE_TAGS_BLOCK_ID : N x OPERAND_BUNDLE_TAG
2441   //
2442   // OPERAND_BUNDLE_TAG - [strchr x N]
2443 
2444   SmallVector<StringRef, 8> Tags;
2445   M.getOperandBundleTags(Tags);
2446 
2447   if (Tags.empty())
2448     return;
2449 
2450   Stream.EnterSubblock(bitc::OPERAND_BUNDLE_TAGS_BLOCK_ID, 3);
2451 
2452   SmallVector<uint64_t, 64> Record;
2453 
2454   for (auto Tag : Tags) {
2455     Record.append(Tag.begin(), Tag.end());
2456 
2457     Stream.EmitRecord(bitc::OPERAND_BUNDLE_TAG, Record, 0);
2458     Record.clear();
2459   }
2460 
2461   Stream.ExitBlock();
2462 }
2463 
2464 void ModuleBitcodeWriter::writeSyncScopeNames() {
2465   SmallVector<StringRef, 8> SSNs;
2466   M.getContext().getSyncScopeNames(SSNs);
2467   if (SSNs.empty())
2468     return;
2469 
2470   Stream.EnterSubblock(bitc::SYNC_SCOPE_NAMES_BLOCK_ID, 2);
2471 
2472   SmallVector<uint64_t, 64> Record;
2473   for (auto SSN : SSNs) {
2474     Record.append(SSN.begin(), SSN.end());
2475     Stream.EmitRecord(bitc::SYNC_SCOPE_NAME, Record, 0);
2476     Record.clear();
2477   }
2478 
2479   Stream.ExitBlock();
2480 }
2481 
2482 void ModuleBitcodeWriter::writeConstants(unsigned FirstVal, unsigned LastVal,
2483                                          bool isGlobal) {
2484   if (FirstVal == LastVal) return;
2485 
2486   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
2487 
2488   unsigned AggregateAbbrev = 0;
2489   unsigned String8Abbrev = 0;
2490   unsigned CString7Abbrev = 0;
2491   unsigned CString6Abbrev = 0;
2492   // If this is a constant pool for the module, emit module-specific abbrevs.
2493   if (isGlobal) {
2494     // Abbrev for CST_CODE_AGGREGATE.
2495     auto Abbv = std::make_shared<BitCodeAbbrev>();
2496     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
2497     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2498     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
2499     AggregateAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2500 
2501     // Abbrev for CST_CODE_STRING.
2502     Abbv = std::make_shared<BitCodeAbbrev>();
2503     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
2504     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2505     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2506     String8Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2507     // Abbrev for CST_CODE_CSTRING.
2508     Abbv = std::make_shared<BitCodeAbbrev>();
2509     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2510     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2511     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2512     CString7Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2513     // Abbrev for CST_CODE_CSTRING.
2514     Abbv = std::make_shared<BitCodeAbbrev>();
2515     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2516     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2517     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2518     CString6Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2519   }
2520 
2521   SmallVector<uint64_t, 64> Record;
2522 
2523   const ValueEnumerator::ValueList &Vals = VE.getValues();
2524   Type *LastTy = nullptr;
2525   for (unsigned i = FirstVal; i != LastVal; ++i) {
2526     const Value *V = Vals[i].first;
2527     // If we need to switch types, do so now.
2528     if (V->getType() != LastTy) {
2529       LastTy = V->getType();
2530       Record.push_back(VE.getTypeID(LastTy));
2531       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
2532                         CONSTANTS_SETTYPE_ABBREV);
2533       Record.clear();
2534     }
2535 
2536     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
2537       Record.push_back(VE.getTypeID(IA->getFunctionType()));
2538       Record.push_back(
2539           unsigned(IA->hasSideEffects()) | unsigned(IA->isAlignStack()) << 1 |
2540           unsigned(IA->getDialect() & 1) << 2 | unsigned(IA->canThrow()) << 3);
2541 
2542       // Add the asm string.
2543       const std::string &AsmStr = IA->getAsmString();
2544       Record.push_back(AsmStr.size());
2545       Record.append(AsmStr.begin(), AsmStr.end());
2546 
2547       // Add the constraint string.
2548       const std::string &ConstraintStr = IA->getConstraintString();
2549       Record.push_back(ConstraintStr.size());
2550       Record.append(ConstraintStr.begin(), ConstraintStr.end());
2551       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
2552       Record.clear();
2553       continue;
2554     }
2555     const Constant *C = cast<Constant>(V);
2556     unsigned Code = -1U;
2557     unsigned AbbrevToUse = 0;
2558     if (C->isNullValue()) {
2559       Code = bitc::CST_CODE_NULL;
2560     } else if (isa<PoisonValue>(C)) {
2561       Code = bitc::CST_CODE_POISON;
2562     } else if (isa<UndefValue>(C)) {
2563       Code = bitc::CST_CODE_UNDEF;
2564     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
2565       if (IV->getBitWidth() <= 64) {
2566         uint64_t V = IV->getSExtValue();
2567         emitSignedInt64(Record, V);
2568         Code = bitc::CST_CODE_INTEGER;
2569         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
2570       } else {                             // Wide integers, > 64 bits in size.
2571         emitWideAPInt(Record, IV->getValue());
2572         Code = bitc::CST_CODE_WIDE_INTEGER;
2573       }
2574     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
2575       Code = bitc::CST_CODE_FLOAT;
2576       Type *Ty = CFP->getType();
2577       if (Ty->isHalfTy() || Ty->isBFloatTy() || Ty->isFloatTy() ||
2578           Ty->isDoubleTy()) {
2579         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
2580       } else if (Ty->isX86_FP80Ty()) {
2581         // api needed to prevent premature destruction
2582         // bits are not in the same order as a normal i80 APInt, compensate.
2583         APInt api = CFP->getValueAPF().bitcastToAPInt();
2584         const uint64_t *p = api.getRawData();
2585         Record.push_back((p[1] << 48) | (p[0] >> 16));
2586         Record.push_back(p[0] & 0xffffLL);
2587       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
2588         APInt api = CFP->getValueAPF().bitcastToAPInt();
2589         const uint64_t *p = api.getRawData();
2590         Record.push_back(p[0]);
2591         Record.push_back(p[1]);
2592       } else {
2593         assert(0 && "Unknown FP type!");
2594       }
2595     } else if (isa<ConstantDataSequential>(C) &&
2596                cast<ConstantDataSequential>(C)->isString()) {
2597       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
2598       // Emit constant strings specially.
2599       unsigned NumElts = Str->getNumElements();
2600       // If this is a null-terminated string, use the denser CSTRING encoding.
2601       if (Str->isCString()) {
2602         Code = bitc::CST_CODE_CSTRING;
2603         --NumElts;  // Don't encode the null, which isn't allowed by char6.
2604       } else {
2605         Code = bitc::CST_CODE_STRING;
2606         AbbrevToUse = String8Abbrev;
2607       }
2608       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
2609       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
2610       for (unsigned i = 0; i != NumElts; ++i) {
2611         unsigned char V = Str->getElementAsInteger(i);
2612         Record.push_back(V);
2613         isCStr7 &= (V & 128) == 0;
2614         if (isCStrChar6)
2615           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
2616       }
2617 
2618       if (isCStrChar6)
2619         AbbrevToUse = CString6Abbrev;
2620       else if (isCStr7)
2621         AbbrevToUse = CString7Abbrev;
2622     } else if (const ConstantDataSequential *CDS =
2623                   dyn_cast<ConstantDataSequential>(C)) {
2624       Code = bitc::CST_CODE_DATA;
2625       Type *EltTy = CDS->getElementType();
2626       if (isa<IntegerType>(EltTy)) {
2627         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2628           Record.push_back(CDS->getElementAsInteger(i));
2629       } else {
2630         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2631           Record.push_back(
2632               CDS->getElementAsAPFloat(i).bitcastToAPInt().getLimitedValue());
2633       }
2634     } else if (isa<ConstantAggregate>(C)) {
2635       Code = bitc::CST_CODE_AGGREGATE;
2636       for (const Value *Op : C->operands())
2637         Record.push_back(VE.getValueID(Op));
2638       AbbrevToUse = AggregateAbbrev;
2639     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
2640       switch (CE->getOpcode()) {
2641       default:
2642         if (Instruction::isCast(CE->getOpcode())) {
2643           Code = bitc::CST_CODE_CE_CAST;
2644           Record.push_back(getEncodedCastOpcode(CE->getOpcode()));
2645           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2646           Record.push_back(VE.getValueID(C->getOperand(0)));
2647           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
2648         } else {
2649           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
2650           Code = bitc::CST_CODE_CE_BINOP;
2651           Record.push_back(getEncodedBinaryOpcode(CE->getOpcode()));
2652           Record.push_back(VE.getValueID(C->getOperand(0)));
2653           Record.push_back(VE.getValueID(C->getOperand(1)));
2654           uint64_t Flags = getOptimizationFlags(CE);
2655           if (Flags != 0)
2656             Record.push_back(Flags);
2657         }
2658         break;
2659       case Instruction::FNeg: {
2660         assert(CE->getNumOperands() == 1 && "Unknown constant expr!");
2661         Code = bitc::CST_CODE_CE_UNOP;
2662         Record.push_back(getEncodedUnaryOpcode(CE->getOpcode()));
2663         Record.push_back(VE.getValueID(C->getOperand(0)));
2664         uint64_t Flags = getOptimizationFlags(CE);
2665         if (Flags != 0)
2666           Record.push_back(Flags);
2667         break;
2668       }
2669       case Instruction::GetElementPtr: {
2670         Code = bitc::CST_CODE_CE_GEP;
2671         const auto *GO = cast<GEPOperator>(C);
2672         Record.push_back(VE.getTypeID(GO->getSourceElementType()));
2673         if (std::optional<unsigned> Idx = GO->getInRangeIndex()) {
2674           Code = bitc::CST_CODE_CE_GEP_WITH_INRANGE_INDEX;
2675           Record.push_back((*Idx << 1) | GO->isInBounds());
2676         } else if (GO->isInBounds())
2677           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
2678         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
2679           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
2680           Record.push_back(VE.getValueID(C->getOperand(i)));
2681         }
2682         break;
2683       }
2684       case Instruction::ExtractElement:
2685         Code = bitc::CST_CODE_CE_EXTRACTELT;
2686         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2687         Record.push_back(VE.getValueID(C->getOperand(0)));
2688         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
2689         Record.push_back(VE.getValueID(C->getOperand(1)));
2690         break;
2691       case Instruction::InsertElement:
2692         Code = bitc::CST_CODE_CE_INSERTELT;
2693         Record.push_back(VE.getValueID(C->getOperand(0)));
2694         Record.push_back(VE.getValueID(C->getOperand(1)));
2695         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
2696         Record.push_back(VE.getValueID(C->getOperand(2)));
2697         break;
2698       case Instruction::ShuffleVector:
2699         // If the return type and argument types are the same, this is a
2700         // standard shufflevector instruction.  If the types are different,
2701         // then the shuffle is widening or truncating the input vectors, and
2702         // the argument type must also be encoded.
2703         if (C->getType() == C->getOperand(0)->getType()) {
2704           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
2705         } else {
2706           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
2707           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2708         }
2709         Record.push_back(VE.getValueID(C->getOperand(0)));
2710         Record.push_back(VE.getValueID(C->getOperand(1)));
2711         Record.push_back(VE.getValueID(CE->getShuffleMaskForBitcode()));
2712         break;
2713       case Instruction::ICmp:
2714       case Instruction::FCmp:
2715         Code = bitc::CST_CODE_CE_CMP;
2716         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2717         Record.push_back(VE.getValueID(C->getOperand(0)));
2718         Record.push_back(VE.getValueID(C->getOperand(1)));
2719         Record.push_back(CE->getPredicate());
2720         break;
2721       }
2722     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
2723       Code = bitc::CST_CODE_BLOCKADDRESS;
2724       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
2725       Record.push_back(VE.getValueID(BA->getFunction()));
2726       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
2727     } else if (const auto *Equiv = dyn_cast<DSOLocalEquivalent>(C)) {
2728       Code = bitc::CST_CODE_DSO_LOCAL_EQUIVALENT;
2729       Record.push_back(VE.getTypeID(Equiv->getGlobalValue()->getType()));
2730       Record.push_back(VE.getValueID(Equiv->getGlobalValue()));
2731     } else if (const auto *NC = dyn_cast<NoCFIValue>(C)) {
2732       Code = bitc::CST_CODE_NO_CFI_VALUE;
2733       Record.push_back(VE.getTypeID(NC->getGlobalValue()->getType()));
2734       Record.push_back(VE.getValueID(NC->getGlobalValue()));
2735     } else {
2736 #ifndef NDEBUG
2737       C->dump();
2738 #endif
2739       llvm_unreachable("Unknown constant!");
2740     }
2741     Stream.EmitRecord(Code, Record, AbbrevToUse);
2742     Record.clear();
2743   }
2744 
2745   Stream.ExitBlock();
2746 }
2747 
2748 void ModuleBitcodeWriter::writeModuleConstants() {
2749   const ValueEnumerator::ValueList &Vals = VE.getValues();
2750 
2751   // Find the first constant to emit, which is the first non-globalvalue value.
2752   // We know globalvalues have been emitted by WriteModuleInfo.
2753   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
2754     if (!isa<GlobalValue>(Vals[i].first)) {
2755       writeConstants(i, Vals.size(), true);
2756       return;
2757     }
2758   }
2759 }
2760 
2761 /// pushValueAndType - The file has to encode both the value and type id for
2762 /// many values, because we need to know what type to create for forward
2763 /// references.  However, most operands are not forward references, so this type
2764 /// field is not needed.
2765 ///
2766 /// This function adds V's value ID to Vals.  If the value ID is higher than the
2767 /// instruction ID, then it is a forward reference, and it also includes the
2768 /// type ID.  The value ID that is written is encoded relative to the InstID.
2769 bool ModuleBitcodeWriter::pushValueAndType(const Value *V, unsigned InstID,
2770                                            SmallVectorImpl<unsigned> &Vals) {
2771   unsigned ValID = VE.getValueID(V);
2772   // Make encoding relative to the InstID.
2773   Vals.push_back(InstID - ValID);
2774   if (ValID >= InstID) {
2775     Vals.push_back(VE.getTypeID(V->getType()));
2776     return true;
2777   }
2778   return false;
2779 }
2780 
2781 void ModuleBitcodeWriter::writeOperandBundles(const CallBase &CS,
2782                                               unsigned InstID) {
2783   SmallVector<unsigned, 64> Record;
2784   LLVMContext &C = CS.getContext();
2785 
2786   for (unsigned i = 0, e = CS.getNumOperandBundles(); i != e; ++i) {
2787     const auto &Bundle = CS.getOperandBundleAt(i);
2788     Record.push_back(C.getOperandBundleTagID(Bundle.getTagName()));
2789 
2790     for (auto &Input : Bundle.Inputs)
2791       pushValueAndType(Input, InstID, Record);
2792 
2793     Stream.EmitRecord(bitc::FUNC_CODE_OPERAND_BUNDLE, Record);
2794     Record.clear();
2795   }
2796 }
2797 
2798 /// pushValue - Like pushValueAndType, but where the type of the value is
2799 /// omitted (perhaps it was already encoded in an earlier operand).
2800 void ModuleBitcodeWriter::pushValue(const Value *V, unsigned InstID,
2801                                     SmallVectorImpl<unsigned> &Vals) {
2802   unsigned ValID = VE.getValueID(V);
2803   Vals.push_back(InstID - ValID);
2804 }
2805 
2806 void ModuleBitcodeWriter::pushValueSigned(const Value *V, unsigned InstID,
2807                                           SmallVectorImpl<uint64_t> &Vals) {
2808   unsigned ValID = VE.getValueID(V);
2809   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
2810   emitSignedInt64(Vals, diff);
2811 }
2812 
2813 /// WriteInstruction - Emit an instruction to the specified stream.
2814 void ModuleBitcodeWriter::writeInstruction(const Instruction &I,
2815                                            unsigned InstID,
2816                                            SmallVectorImpl<unsigned> &Vals) {
2817   unsigned Code = 0;
2818   unsigned AbbrevToUse = 0;
2819   VE.setInstructionID(&I);
2820   switch (I.getOpcode()) {
2821   default:
2822     if (Instruction::isCast(I.getOpcode())) {
2823       Code = bitc::FUNC_CODE_INST_CAST;
2824       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2825         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
2826       Vals.push_back(VE.getTypeID(I.getType()));
2827       Vals.push_back(getEncodedCastOpcode(I.getOpcode()));
2828     } else {
2829       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
2830       Code = bitc::FUNC_CODE_INST_BINOP;
2831       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2832         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
2833       pushValue(I.getOperand(1), InstID, Vals);
2834       Vals.push_back(getEncodedBinaryOpcode(I.getOpcode()));
2835       uint64_t Flags = getOptimizationFlags(&I);
2836       if (Flags != 0) {
2837         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
2838           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
2839         Vals.push_back(Flags);
2840       }
2841     }
2842     break;
2843   case Instruction::FNeg: {
2844     Code = bitc::FUNC_CODE_INST_UNOP;
2845     if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2846       AbbrevToUse = FUNCTION_INST_UNOP_ABBREV;
2847     Vals.push_back(getEncodedUnaryOpcode(I.getOpcode()));
2848     uint64_t Flags = getOptimizationFlags(&I);
2849     if (Flags != 0) {
2850       if (AbbrevToUse == FUNCTION_INST_UNOP_ABBREV)
2851         AbbrevToUse = FUNCTION_INST_UNOP_FLAGS_ABBREV;
2852       Vals.push_back(Flags);
2853     }
2854     break;
2855   }
2856   case Instruction::GetElementPtr: {
2857     Code = bitc::FUNC_CODE_INST_GEP;
2858     AbbrevToUse = FUNCTION_INST_GEP_ABBREV;
2859     auto &GEPInst = cast<GetElementPtrInst>(I);
2860     Vals.push_back(GEPInst.isInBounds());
2861     Vals.push_back(VE.getTypeID(GEPInst.getSourceElementType()));
2862     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
2863       pushValueAndType(I.getOperand(i), InstID, Vals);
2864     break;
2865   }
2866   case Instruction::ExtractValue: {
2867     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
2868     pushValueAndType(I.getOperand(0), InstID, Vals);
2869     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
2870     Vals.append(EVI->idx_begin(), EVI->idx_end());
2871     break;
2872   }
2873   case Instruction::InsertValue: {
2874     Code = bitc::FUNC_CODE_INST_INSERTVAL;
2875     pushValueAndType(I.getOperand(0), InstID, Vals);
2876     pushValueAndType(I.getOperand(1), InstID, Vals);
2877     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
2878     Vals.append(IVI->idx_begin(), IVI->idx_end());
2879     break;
2880   }
2881   case Instruction::Select: {
2882     Code = bitc::FUNC_CODE_INST_VSELECT;
2883     pushValueAndType(I.getOperand(1), InstID, Vals);
2884     pushValue(I.getOperand(2), InstID, Vals);
2885     pushValueAndType(I.getOperand(0), InstID, Vals);
2886     uint64_t Flags = getOptimizationFlags(&I);
2887     if (Flags != 0)
2888       Vals.push_back(Flags);
2889     break;
2890   }
2891   case Instruction::ExtractElement:
2892     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
2893     pushValueAndType(I.getOperand(0), InstID, Vals);
2894     pushValueAndType(I.getOperand(1), InstID, Vals);
2895     break;
2896   case Instruction::InsertElement:
2897     Code = bitc::FUNC_CODE_INST_INSERTELT;
2898     pushValueAndType(I.getOperand(0), InstID, Vals);
2899     pushValue(I.getOperand(1), InstID, Vals);
2900     pushValueAndType(I.getOperand(2), InstID, Vals);
2901     break;
2902   case Instruction::ShuffleVector:
2903     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
2904     pushValueAndType(I.getOperand(0), InstID, Vals);
2905     pushValue(I.getOperand(1), InstID, Vals);
2906     pushValue(cast<ShuffleVectorInst>(I).getShuffleMaskForBitcode(), InstID,
2907               Vals);
2908     break;
2909   case Instruction::ICmp:
2910   case Instruction::FCmp: {
2911     // compare returning Int1Ty or vector of Int1Ty
2912     Code = bitc::FUNC_CODE_INST_CMP2;
2913     pushValueAndType(I.getOperand(0), InstID, Vals);
2914     pushValue(I.getOperand(1), InstID, Vals);
2915     Vals.push_back(cast<CmpInst>(I).getPredicate());
2916     uint64_t Flags = getOptimizationFlags(&I);
2917     if (Flags != 0)
2918       Vals.push_back(Flags);
2919     break;
2920   }
2921 
2922   case Instruction::Ret:
2923     {
2924       Code = bitc::FUNC_CODE_INST_RET;
2925       unsigned NumOperands = I.getNumOperands();
2926       if (NumOperands == 0)
2927         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
2928       else if (NumOperands == 1) {
2929         if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2930           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
2931       } else {
2932         for (unsigned i = 0, e = NumOperands; i != e; ++i)
2933           pushValueAndType(I.getOperand(i), InstID, Vals);
2934       }
2935     }
2936     break;
2937   case Instruction::Br:
2938     {
2939       Code = bitc::FUNC_CODE_INST_BR;
2940       const BranchInst &II = cast<BranchInst>(I);
2941       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
2942       if (II.isConditional()) {
2943         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
2944         pushValue(II.getCondition(), InstID, Vals);
2945       }
2946     }
2947     break;
2948   case Instruction::Switch:
2949     {
2950       Code = bitc::FUNC_CODE_INST_SWITCH;
2951       const SwitchInst &SI = cast<SwitchInst>(I);
2952       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
2953       pushValue(SI.getCondition(), InstID, Vals);
2954       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
2955       for (auto Case : SI.cases()) {
2956         Vals.push_back(VE.getValueID(Case.getCaseValue()));
2957         Vals.push_back(VE.getValueID(Case.getCaseSuccessor()));
2958       }
2959     }
2960     break;
2961   case Instruction::IndirectBr:
2962     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
2963     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2964     // Encode the address operand as relative, but not the basic blocks.
2965     pushValue(I.getOperand(0), InstID, Vals);
2966     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
2967       Vals.push_back(VE.getValueID(I.getOperand(i)));
2968     break;
2969 
2970   case Instruction::Invoke: {
2971     const InvokeInst *II = cast<InvokeInst>(&I);
2972     const Value *Callee = II->getCalledOperand();
2973     FunctionType *FTy = II->getFunctionType();
2974 
2975     if (II->hasOperandBundles())
2976       writeOperandBundles(*II, InstID);
2977 
2978     Code = bitc::FUNC_CODE_INST_INVOKE;
2979 
2980     Vals.push_back(VE.getAttributeListID(II->getAttributes()));
2981     Vals.push_back(II->getCallingConv() | 1 << 13);
2982     Vals.push_back(VE.getValueID(II->getNormalDest()));
2983     Vals.push_back(VE.getValueID(II->getUnwindDest()));
2984     Vals.push_back(VE.getTypeID(FTy));
2985     pushValueAndType(Callee, InstID, Vals);
2986 
2987     // Emit value #'s for the fixed parameters.
2988     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
2989       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
2990 
2991     // Emit type/value pairs for varargs params.
2992     if (FTy->isVarArg()) {
2993       for (unsigned i = FTy->getNumParams(), e = II->arg_size(); i != e; ++i)
2994         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
2995     }
2996     break;
2997   }
2998   case Instruction::Resume:
2999     Code = bitc::FUNC_CODE_INST_RESUME;
3000     pushValueAndType(I.getOperand(0), InstID, Vals);
3001     break;
3002   case Instruction::CleanupRet: {
3003     Code = bitc::FUNC_CODE_INST_CLEANUPRET;
3004     const auto &CRI = cast<CleanupReturnInst>(I);
3005     pushValue(CRI.getCleanupPad(), InstID, Vals);
3006     if (CRI.hasUnwindDest())
3007       Vals.push_back(VE.getValueID(CRI.getUnwindDest()));
3008     break;
3009   }
3010   case Instruction::CatchRet: {
3011     Code = bitc::FUNC_CODE_INST_CATCHRET;
3012     const auto &CRI = cast<CatchReturnInst>(I);
3013     pushValue(CRI.getCatchPad(), InstID, Vals);
3014     Vals.push_back(VE.getValueID(CRI.getSuccessor()));
3015     break;
3016   }
3017   case Instruction::CleanupPad:
3018   case Instruction::CatchPad: {
3019     const auto &FuncletPad = cast<FuncletPadInst>(I);
3020     Code = isa<CatchPadInst>(FuncletPad) ? bitc::FUNC_CODE_INST_CATCHPAD
3021                                          : bitc::FUNC_CODE_INST_CLEANUPPAD;
3022     pushValue(FuncletPad.getParentPad(), InstID, Vals);
3023 
3024     unsigned NumArgOperands = FuncletPad.arg_size();
3025     Vals.push_back(NumArgOperands);
3026     for (unsigned Op = 0; Op != NumArgOperands; ++Op)
3027       pushValueAndType(FuncletPad.getArgOperand(Op), InstID, Vals);
3028     break;
3029   }
3030   case Instruction::CatchSwitch: {
3031     Code = bitc::FUNC_CODE_INST_CATCHSWITCH;
3032     const auto &CatchSwitch = cast<CatchSwitchInst>(I);
3033 
3034     pushValue(CatchSwitch.getParentPad(), InstID, Vals);
3035 
3036     unsigned NumHandlers = CatchSwitch.getNumHandlers();
3037     Vals.push_back(NumHandlers);
3038     for (const BasicBlock *CatchPadBB : CatchSwitch.handlers())
3039       Vals.push_back(VE.getValueID(CatchPadBB));
3040 
3041     if (CatchSwitch.hasUnwindDest())
3042       Vals.push_back(VE.getValueID(CatchSwitch.getUnwindDest()));
3043     break;
3044   }
3045   case Instruction::CallBr: {
3046     const CallBrInst *CBI = cast<CallBrInst>(&I);
3047     const Value *Callee = CBI->getCalledOperand();
3048     FunctionType *FTy = CBI->getFunctionType();
3049 
3050     if (CBI->hasOperandBundles())
3051       writeOperandBundles(*CBI, InstID);
3052 
3053     Code = bitc::FUNC_CODE_INST_CALLBR;
3054 
3055     Vals.push_back(VE.getAttributeListID(CBI->getAttributes()));
3056 
3057     Vals.push_back(CBI->getCallingConv() << bitc::CALL_CCONV |
3058                    1 << bitc::CALL_EXPLICIT_TYPE);
3059 
3060     Vals.push_back(VE.getValueID(CBI->getDefaultDest()));
3061     Vals.push_back(CBI->getNumIndirectDests());
3062     for (unsigned i = 0, e = CBI->getNumIndirectDests(); i != e; ++i)
3063       Vals.push_back(VE.getValueID(CBI->getIndirectDest(i)));
3064 
3065     Vals.push_back(VE.getTypeID(FTy));
3066     pushValueAndType(Callee, InstID, Vals);
3067 
3068     // Emit value #'s for the fixed parameters.
3069     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
3070       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
3071 
3072     // Emit type/value pairs for varargs params.
3073     if (FTy->isVarArg()) {
3074       for (unsigned i = FTy->getNumParams(), e = CBI->arg_size(); i != e; ++i)
3075         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
3076     }
3077     break;
3078   }
3079   case Instruction::Unreachable:
3080     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
3081     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
3082     break;
3083 
3084   case Instruction::PHI: {
3085     const PHINode &PN = cast<PHINode>(I);
3086     Code = bitc::FUNC_CODE_INST_PHI;
3087     // With the newer instruction encoding, forward references could give
3088     // negative valued IDs.  This is most common for PHIs, so we use
3089     // signed VBRs.
3090     SmallVector<uint64_t, 128> Vals64;
3091     Vals64.push_back(VE.getTypeID(PN.getType()));
3092     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
3093       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64);
3094       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
3095     }
3096 
3097     uint64_t Flags = getOptimizationFlags(&I);
3098     if (Flags != 0)
3099       Vals64.push_back(Flags);
3100 
3101     // Emit a Vals64 vector and exit.
3102     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
3103     Vals64.clear();
3104     return;
3105   }
3106 
3107   case Instruction::LandingPad: {
3108     const LandingPadInst &LP = cast<LandingPadInst>(I);
3109     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
3110     Vals.push_back(VE.getTypeID(LP.getType()));
3111     Vals.push_back(LP.isCleanup());
3112     Vals.push_back(LP.getNumClauses());
3113     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
3114       if (LP.isCatch(I))
3115         Vals.push_back(LandingPadInst::Catch);
3116       else
3117         Vals.push_back(LandingPadInst::Filter);
3118       pushValueAndType(LP.getClause(I), InstID, Vals);
3119     }
3120     break;
3121   }
3122 
3123   case Instruction::Alloca: {
3124     Code = bitc::FUNC_CODE_INST_ALLOCA;
3125     const AllocaInst &AI = cast<AllocaInst>(I);
3126     Vals.push_back(VE.getTypeID(AI.getAllocatedType()));
3127     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
3128     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
3129     using APV = AllocaPackedValues;
3130     unsigned Record = 0;
3131     unsigned EncodedAlign = getEncodedAlign(AI.getAlign());
3132     Bitfield::set<APV::AlignLower>(
3133         Record, EncodedAlign & ((1 << APV::AlignLower::Bits) - 1));
3134     Bitfield::set<APV::AlignUpper>(Record,
3135                                    EncodedAlign >> APV::AlignLower::Bits);
3136     Bitfield::set<APV::UsedWithInAlloca>(Record, AI.isUsedWithInAlloca());
3137     Bitfield::set<APV::ExplicitType>(Record, true);
3138     Bitfield::set<APV::SwiftError>(Record, AI.isSwiftError());
3139     Vals.push_back(Record);
3140 
3141     unsigned AS = AI.getAddressSpace();
3142     if (AS != M.getDataLayout().getAllocaAddrSpace())
3143       Vals.push_back(AS);
3144     break;
3145   }
3146 
3147   case Instruction::Load:
3148     if (cast<LoadInst>(I).isAtomic()) {
3149       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
3150       pushValueAndType(I.getOperand(0), InstID, Vals);
3151     } else {
3152       Code = bitc::FUNC_CODE_INST_LOAD;
3153       if (!pushValueAndType(I.getOperand(0), InstID, Vals)) // ptr
3154         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
3155     }
3156     Vals.push_back(VE.getTypeID(I.getType()));
3157     Vals.push_back(getEncodedAlign(cast<LoadInst>(I).getAlign()));
3158     Vals.push_back(cast<LoadInst>(I).isVolatile());
3159     if (cast<LoadInst>(I).isAtomic()) {
3160       Vals.push_back(getEncodedOrdering(cast<LoadInst>(I).getOrdering()));
3161       Vals.push_back(getEncodedSyncScopeID(cast<LoadInst>(I).getSyncScopeID()));
3162     }
3163     break;
3164   case Instruction::Store:
3165     if (cast<StoreInst>(I).isAtomic())
3166       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
3167     else
3168       Code = bitc::FUNC_CODE_INST_STORE;
3169     pushValueAndType(I.getOperand(1), InstID, Vals); // ptrty + ptr
3170     pushValueAndType(I.getOperand(0), InstID, Vals); // valty + val
3171     Vals.push_back(getEncodedAlign(cast<StoreInst>(I).getAlign()));
3172     Vals.push_back(cast<StoreInst>(I).isVolatile());
3173     if (cast<StoreInst>(I).isAtomic()) {
3174       Vals.push_back(getEncodedOrdering(cast<StoreInst>(I).getOrdering()));
3175       Vals.push_back(
3176           getEncodedSyncScopeID(cast<StoreInst>(I).getSyncScopeID()));
3177     }
3178     break;
3179   case Instruction::AtomicCmpXchg:
3180     Code = bitc::FUNC_CODE_INST_CMPXCHG;
3181     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
3182     pushValueAndType(I.getOperand(1), InstID, Vals); // cmp.
3183     pushValue(I.getOperand(2), InstID, Vals);        // newval.
3184     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
3185     Vals.push_back(
3186         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
3187     Vals.push_back(
3188         getEncodedSyncScopeID(cast<AtomicCmpXchgInst>(I).getSyncScopeID()));
3189     Vals.push_back(
3190         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
3191     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
3192     Vals.push_back(getEncodedAlign(cast<AtomicCmpXchgInst>(I).getAlign()));
3193     break;
3194   case Instruction::AtomicRMW:
3195     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
3196     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
3197     pushValueAndType(I.getOperand(1), InstID, Vals); // valty + val
3198     Vals.push_back(
3199         getEncodedRMWOperation(cast<AtomicRMWInst>(I).getOperation()));
3200     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
3201     Vals.push_back(getEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
3202     Vals.push_back(
3203         getEncodedSyncScopeID(cast<AtomicRMWInst>(I).getSyncScopeID()));
3204     Vals.push_back(getEncodedAlign(cast<AtomicRMWInst>(I).getAlign()));
3205     break;
3206   case Instruction::Fence:
3207     Code = bitc::FUNC_CODE_INST_FENCE;
3208     Vals.push_back(getEncodedOrdering(cast<FenceInst>(I).getOrdering()));
3209     Vals.push_back(getEncodedSyncScopeID(cast<FenceInst>(I).getSyncScopeID()));
3210     break;
3211   case Instruction::Call: {
3212     const CallInst &CI = cast<CallInst>(I);
3213     FunctionType *FTy = CI.getFunctionType();
3214 
3215     if (CI.hasOperandBundles())
3216       writeOperandBundles(CI, InstID);
3217 
3218     Code = bitc::FUNC_CODE_INST_CALL;
3219 
3220     Vals.push_back(VE.getAttributeListID(CI.getAttributes()));
3221 
3222     unsigned Flags = getOptimizationFlags(&I);
3223     Vals.push_back(CI.getCallingConv() << bitc::CALL_CCONV |
3224                    unsigned(CI.isTailCall()) << bitc::CALL_TAIL |
3225                    unsigned(CI.isMustTailCall()) << bitc::CALL_MUSTTAIL |
3226                    1 << bitc::CALL_EXPLICIT_TYPE |
3227                    unsigned(CI.isNoTailCall()) << bitc::CALL_NOTAIL |
3228                    unsigned(Flags != 0) << bitc::CALL_FMF);
3229     if (Flags != 0)
3230       Vals.push_back(Flags);
3231 
3232     Vals.push_back(VE.getTypeID(FTy));
3233     pushValueAndType(CI.getCalledOperand(), InstID, Vals); // Callee
3234 
3235     // Emit value #'s for the fixed parameters.
3236     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
3237       // Check for labels (can happen with asm labels).
3238       if (FTy->getParamType(i)->isLabelTy())
3239         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
3240       else
3241         pushValue(CI.getArgOperand(i), InstID, Vals); // fixed param.
3242     }
3243 
3244     // Emit type/value pairs for varargs params.
3245     if (FTy->isVarArg()) {
3246       for (unsigned i = FTy->getNumParams(), e = CI.arg_size(); i != e; ++i)
3247         pushValueAndType(CI.getArgOperand(i), InstID, Vals); // varargs
3248     }
3249     break;
3250   }
3251   case Instruction::VAArg:
3252     Code = bitc::FUNC_CODE_INST_VAARG;
3253     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
3254     pushValue(I.getOperand(0), InstID, Vals);                   // valist.
3255     Vals.push_back(VE.getTypeID(I.getType())); // restype.
3256     break;
3257   case Instruction::Freeze:
3258     Code = bitc::FUNC_CODE_INST_FREEZE;
3259     pushValueAndType(I.getOperand(0), InstID, Vals);
3260     break;
3261   }
3262 
3263   Stream.EmitRecord(Code, Vals, AbbrevToUse);
3264   Vals.clear();
3265 }
3266 
3267 /// Write a GlobalValue VST to the module. The purpose of this data structure is
3268 /// to allow clients to efficiently find the function body.
3269 void ModuleBitcodeWriter::writeGlobalValueSymbolTable(
3270   DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3271   // Get the offset of the VST we are writing, and backpatch it into
3272   // the VST forward declaration record.
3273   uint64_t VSTOffset = Stream.GetCurrentBitNo();
3274   // The BitcodeStartBit was the stream offset of the identification block.
3275   VSTOffset -= bitcodeStartBit();
3276   assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
3277   // Note that we add 1 here because the offset is relative to one word
3278   // before the start of the identification block, which was historically
3279   // always the start of the regular bitcode header.
3280   Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32 + 1);
3281 
3282   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3283 
3284   auto Abbv = std::make_shared<BitCodeAbbrev>();
3285   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
3286   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
3287   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
3288   unsigned FnEntryAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3289 
3290   for (const Function &F : M) {
3291     uint64_t Record[2];
3292 
3293     if (F.isDeclaration())
3294       continue;
3295 
3296     Record[0] = VE.getValueID(&F);
3297 
3298     // Save the word offset of the function (from the start of the
3299     // actual bitcode written to the stream).
3300     uint64_t BitcodeIndex = FunctionToBitcodeIndex[&F] - bitcodeStartBit();
3301     assert((BitcodeIndex & 31) == 0 && "function block not 32-bit aligned");
3302     // Note that we add 1 here because the offset is relative to one word
3303     // before the start of the identification block, which was historically
3304     // always the start of the regular bitcode header.
3305     Record[1] = BitcodeIndex / 32 + 1;
3306 
3307     Stream.EmitRecord(bitc::VST_CODE_FNENTRY, Record, FnEntryAbbrev);
3308   }
3309 
3310   Stream.ExitBlock();
3311 }
3312 
3313 /// Emit names for arguments, instructions and basic blocks in a function.
3314 void ModuleBitcodeWriter::writeFunctionLevelValueSymbolTable(
3315     const ValueSymbolTable &VST) {
3316   if (VST.empty())
3317     return;
3318 
3319   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3320 
3321   // FIXME: Set up the abbrev, we know how many values there are!
3322   // FIXME: We know if the type names can use 7-bit ascii.
3323   SmallVector<uint64_t, 64> NameVals;
3324 
3325   for (const ValueName &Name : VST) {
3326     // Figure out the encoding to use for the name.
3327     StringEncoding Bits = getStringEncoding(Name.getKey());
3328 
3329     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
3330     NameVals.push_back(VE.getValueID(Name.getValue()));
3331 
3332     // VST_CODE_ENTRY:   [valueid, namechar x N]
3333     // VST_CODE_BBENTRY: [bbid, namechar x N]
3334     unsigned Code;
3335     if (isa<BasicBlock>(Name.getValue())) {
3336       Code = bitc::VST_CODE_BBENTRY;
3337       if (Bits == SE_Char6)
3338         AbbrevToUse = VST_BBENTRY_6_ABBREV;
3339     } else {
3340       Code = bitc::VST_CODE_ENTRY;
3341       if (Bits == SE_Char6)
3342         AbbrevToUse = VST_ENTRY_6_ABBREV;
3343       else if (Bits == SE_Fixed7)
3344         AbbrevToUse = VST_ENTRY_7_ABBREV;
3345     }
3346 
3347     for (const auto P : Name.getKey())
3348       NameVals.push_back((unsigned char)P);
3349 
3350     // Emit the finished record.
3351     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
3352     NameVals.clear();
3353   }
3354 
3355   Stream.ExitBlock();
3356 }
3357 
3358 void ModuleBitcodeWriter::writeUseList(UseListOrder &&Order) {
3359   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
3360   unsigned Code;
3361   if (isa<BasicBlock>(Order.V))
3362     Code = bitc::USELIST_CODE_BB;
3363   else
3364     Code = bitc::USELIST_CODE_DEFAULT;
3365 
3366   SmallVector<uint64_t, 64> Record(Order.Shuffle.begin(), Order.Shuffle.end());
3367   Record.push_back(VE.getValueID(Order.V));
3368   Stream.EmitRecord(Code, Record);
3369 }
3370 
3371 void ModuleBitcodeWriter::writeUseListBlock(const Function *F) {
3372   assert(VE.shouldPreserveUseListOrder() &&
3373          "Expected to be preserving use-list order");
3374 
3375   auto hasMore = [&]() {
3376     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
3377   };
3378   if (!hasMore())
3379     // Nothing to do.
3380     return;
3381 
3382   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
3383   while (hasMore()) {
3384     writeUseList(std::move(VE.UseListOrders.back()));
3385     VE.UseListOrders.pop_back();
3386   }
3387   Stream.ExitBlock();
3388 }
3389 
3390 /// Emit a function body to the module stream.
3391 void ModuleBitcodeWriter::writeFunction(
3392     const Function &F,
3393     DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3394   // Save the bitcode index of the start of this function block for recording
3395   // in the VST.
3396   FunctionToBitcodeIndex[&F] = Stream.GetCurrentBitNo();
3397 
3398   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
3399   VE.incorporateFunction(F);
3400 
3401   SmallVector<unsigned, 64> Vals;
3402 
3403   // Emit the number of basic blocks, so the reader can create them ahead of
3404   // time.
3405   Vals.push_back(VE.getBasicBlocks().size());
3406   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
3407   Vals.clear();
3408 
3409   // If there are function-local constants, emit them now.
3410   unsigned CstStart, CstEnd;
3411   VE.getFunctionConstantRange(CstStart, CstEnd);
3412   writeConstants(CstStart, CstEnd, false);
3413 
3414   // If there is function-local metadata, emit it now.
3415   writeFunctionMetadata(F);
3416 
3417   // Keep a running idea of what the instruction ID is.
3418   unsigned InstID = CstEnd;
3419 
3420   bool NeedsMetadataAttachment = F.hasMetadata();
3421 
3422   DILocation *LastDL = nullptr;
3423   SmallSetVector<Function *, 4> BlockAddressUsers;
3424 
3425   // Finally, emit all the instructions, in order.
3426   for (const BasicBlock &BB : F) {
3427     for (const Instruction &I : BB) {
3428       writeInstruction(I, InstID, Vals);
3429 
3430       if (!I.getType()->isVoidTy())
3431         ++InstID;
3432 
3433       // If the instruction has metadata, write a metadata attachment later.
3434       NeedsMetadataAttachment |= I.hasMetadataOtherThanDebugLoc();
3435 
3436       // If the instruction has a debug location, emit it.
3437       DILocation *DL = I.getDebugLoc();
3438       if (!DL)
3439         continue;
3440 
3441       if (DL == LastDL) {
3442         // Just repeat the same debug loc as last time.
3443         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
3444         continue;
3445       }
3446 
3447       Vals.push_back(DL->getLine());
3448       Vals.push_back(DL->getColumn());
3449       Vals.push_back(VE.getMetadataOrNullID(DL->getScope()));
3450       Vals.push_back(VE.getMetadataOrNullID(DL->getInlinedAt()));
3451       Vals.push_back(DL->isImplicitCode());
3452       Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
3453       Vals.clear();
3454 
3455       LastDL = DL;
3456     }
3457 
3458     if (BlockAddress *BA = BlockAddress::lookup(&BB)) {
3459       SmallVector<Value *> Worklist{BA};
3460       SmallPtrSet<Value *, 8> Visited{BA};
3461       while (!Worklist.empty()) {
3462         Value *V = Worklist.pop_back_val();
3463         for (User *U : V->users()) {
3464           if (auto *I = dyn_cast<Instruction>(U)) {
3465             Function *P = I->getFunction();
3466             if (P != &F)
3467               BlockAddressUsers.insert(P);
3468           } else if (isa<Constant>(U) && !isa<GlobalValue>(U) &&
3469                      Visited.insert(U).second)
3470             Worklist.push_back(U);
3471         }
3472       }
3473     }
3474   }
3475 
3476   if (!BlockAddressUsers.empty()) {
3477     Vals.resize(BlockAddressUsers.size());
3478     for (auto I : llvm::enumerate(BlockAddressUsers))
3479       Vals[I.index()] = VE.getValueID(I.value());
3480     Stream.EmitRecord(bitc::FUNC_CODE_BLOCKADDR_USERS, Vals);
3481     Vals.clear();
3482   }
3483 
3484   // Emit names for all the instructions etc.
3485   if (auto *Symtab = F.getValueSymbolTable())
3486     writeFunctionLevelValueSymbolTable(*Symtab);
3487 
3488   if (NeedsMetadataAttachment)
3489     writeFunctionMetadataAttachment(F);
3490   if (VE.shouldPreserveUseListOrder())
3491     writeUseListBlock(&F);
3492   VE.purgeFunction();
3493   Stream.ExitBlock();
3494 }
3495 
3496 // Emit blockinfo, which defines the standard abbreviations etc.
3497 void ModuleBitcodeWriter::writeBlockInfo() {
3498   // We only want to emit block info records for blocks that have multiple
3499   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
3500   // Other blocks can define their abbrevs inline.
3501   Stream.EnterBlockInfoBlock();
3502 
3503   { // 8-bit fixed-width VST_CODE_ENTRY/VST_CODE_BBENTRY strings.
3504     auto Abbv = std::make_shared<BitCodeAbbrev>();
3505     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
3506     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3507     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3508     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3509     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3510         VST_ENTRY_8_ABBREV)
3511       llvm_unreachable("Unexpected abbrev ordering!");
3512   }
3513 
3514   { // 7-bit fixed width VST_CODE_ENTRY strings.
3515     auto Abbv = std::make_shared<BitCodeAbbrev>();
3516     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3517     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3518     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3519     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3520     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3521         VST_ENTRY_7_ABBREV)
3522       llvm_unreachable("Unexpected abbrev ordering!");
3523   }
3524   { // 6-bit char6 VST_CODE_ENTRY strings.
3525     auto Abbv = std::make_shared<BitCodeAbbrev>();
3526     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3527     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3528     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3529     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3530     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3531         VST_ENTRY_6_ABBREV)
3532       llvm_unreachable("Unexpected abbrev ordering!");
3533   }
3534   { // 6-bit char6 VST_CODE_BBENTRY strings.
3535     auto Abbv = std::make_shared<BitCodeAbbrev>();
3536     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
3537     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3538     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3539     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3540     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3541         VST_BBENTRY_6_ABBREV)
3542       llvm_unreachable("Unexpected abbrev ordering!");
3543   }
3544 
3545   { // SETTYPE abbrev for CONSTANTS_BLOCK.
3546     auto Abbv = std::make_shared<BitCodeAbbrev>();
3547     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
3548     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
3549                               VE.computeBitsRequiredForTypeIndicies()));
3550     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3551         CONSTANTS_SETTYPE_ABBREV)
3552       llvm_unreachable("Unexpected abbrev ordering!");
3553   }
3554 
3555   { // INTEGER abbrev for CONSTANTS_BLOCK.
3556     auto Abbv = std::make_shared<BitCodeAbbrev>();
3557     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
3558     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3559     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3560         CONSTANTS_INTEGER_ABBREV)
3561       llvm_unreachable("Unexpected abbrev ordering!");
3562   }
3563 
3564   { // CE_CAST abbrev for CONSTANTS_BLOCK.
3565     auto Abbv = std::make_shared<BitCodeAbbrev>();
3566     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
3567     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
3568     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
3569                               VE.computeBitsRequiredForTypeIndicies()));
3570     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
3571 
3572     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3573         CONSTANTS_CE_CAST_Abbrev)
3574       llvm_unreachable("Unexpected abbrev ordering!");
3575   }
3576   { // NULL abbrev for CONSTANTS_BLOCK.
3577     auto Abbv = std::make_shared<BitCodeAbbrev>();
3578     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
3579     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3580         CONSTANTS_NULL_Abbrev)
3581       llvm_unreachable("Unexpected abbrev ordering!");
3582   }
3583 
3584   // FIXME: This should only use space for first class types!
3585 
3586   { // INST_LOAD abbrev for FUNCTION_BLOCK.
3587     auto Abbv = std::make_shared<BitCodeAbbrev>();
3588     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
3589     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
3590     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
3591                               VE.computeBitsRequiredForTypeIndicies()));
3592     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
3593     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
3594     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3595         FUNCTION_INST_LOAD_ABBREV)
3596       llvm_unreachable("Unexpected abbrev ordering!");
3597   }
3598   { // INST_UNOP abbrev for FUNCTION_BLOCK.
3599     auto Abbv = std::make_shared<BitCodeAbbrev>();
3600     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3601     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3602     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3603     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3604         FUNCTION_INST_UNOP_ABBREV)
3605       llvm_unreachable("Unexpected abbrev ordering!");
3606   }
3607   { // INST_UNOP_FLAGS abbrev for FUNCTION_BLOCK.
3608     auto Abbv = std::make_shared<BitCodeAbbrev>();
3609     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3610     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3611     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3612     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3613     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3614         FUNCTION_INST_UNOP_FLAGS_ABBREV)
3615       llvm_unreachable("Unexpected abbrev ordering!");
3616   }
3617   { // INST_BINOP abbrev for FUNCTION_BLOCK.
3618     auto Abbv = std::make_shared<BitCodeAbbrev>();
3619     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3620     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3621     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3622     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3623     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3624         FUNCTION_INST_BINOP_ABBREV)
3625       llvm_unreachable("Unexpected abbrev ordering!");
3626   }
3627   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
3628     auto Abbv = std::make_shared<BitCodeAbbrev>();
3629     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3630     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3631     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3632     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3633     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3634     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3635         FUNCTION_INST_BINOP_FLAGS_ABBREV)
3636       llvm_unreachable("Unexpected abbrev ordering!");
3637   }
3638   { // INST_CAST abbrev for FUNCTION_BLOCK.
3639     auto Abbv = std::make_shared<BitCodeAbbrev>();
3640     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
3641     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
3642     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
3643                               VE.computeBitsRequiredForTypeIndicies()));
3644     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
3645     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3646         FUNCTION_INST_CAST_ABBREV)
3647       llvm_unreachable("Unexpected abbrev ordering!");
3648   }
3649 
3650   { // INST_RET abbrev for FUNCTION_BLOCK.
3651     auto Abbv = std::make_shared<BitCodeAbbrev>();
3652     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3653     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3654         FUNCTION_INST_RET_VOID_ABBREV)
3655       llvm_unreachable("Unexpected abbrev ordering!");
3656   }
3657   { // INST_RET abbrev for FUNCTION_BLOCK.
3658     auto Abbv = std::make_shared<BitCodeAbbrev>();
3659     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3660     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
3661     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3662         FUNCTION_INST_RET_VAL_ABBREV)
3663       llvm_unreachable("Unexpected abbrev ordering!");
3664   }
3665   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
3666     auto Abbv = std::make_shared<BitCodeAbbrev>();
3667     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
3668     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3669         FUNCTION_INST_UNREACHABLE_ABBREV)
3670       llvm_unreachable("Unexpected abbrev ordering!");
3671   }
3672   {
3673     auto Abbv = std::make_shared<BitCodeAbbrev>();
3674     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_GEP));
3675     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
3676     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, // dest ty
3677                               Log2_32_Ceil(VE.getTypes().size() + 1)));
3678     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3679     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
3680     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3681         FUNCTION_INST_GEP_ABBREV)
3682       llvm_unreachable("Unexpected abbrev ordering!");
3683   }
3684 
3685   Stream.ExitBlock();
3686 }
3687 
3688 /// Write the module path strings, currently only used when generating
3689 /// a combined index file.
3690 void IndexBitcodeWriter::writeModStrings() {
3691   Stream.EnterSubblock(bitc::MODULE_STRTAB_BLOCK_ID, 3);
3692 
3693   // TODO: See which abbrev sizes we actually need to emit
3694 
3695   // 8-bit fixed-width MST_ENTRY strings.
3696   auto 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, 8));
3701   unsigned Abbrev8Bit = Stream.EmitAbbrev(std::move(Abbv));
3702 
3703   // 7-bit fixed width 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::Fixed, 7));
3709   unsigned Abbrev7Bit = Stream.EmitAbbrev(std::move(Abbv));
3710 
3711   // 6-bit char6 MST_ENTRY strings.
3712   Abbv = std::make_shared<BitCodeAbbrev>();
3713   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3714   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3715   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3716   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3717   unsigned Abbrev6Bit = Stream.EmitAbbrev(std::move(Abbv));
3718 
3719   // Module Hash, 160 bits SHA1. Optionally, emitted after each MST_CODE_ENTRY.
3720   Abbv = std::make_shared<BitCodeAbbrev>();
3721   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_HASH));
3722   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3723   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3724   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3725   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3726   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3727   unsigned AbbrevHash = Stream.EmitAbbrev(std::move(Abbv));
3728 
3729   SmallVector<unsigned, 64> Vals;
3730   forEachModule([&](const StringMapEntry<ModuleHash> &MPSE) {
3731     StringRef Key = MPSE.getKey();
3732     const auto &Hash = MPSE.getValue();
3733     StringEncoding Bits = getStringEncoding(Key);
3734     unsigned AbbrevToUse = Abbrev8Bit;
3735     if (Bits == SE_Char6)
3736       AbbrevToUse = Abbrev6Bit;
3737     else if (Bits == SE_Fixed7)
3738       AbbrevToUse = Abbrev7Bit;
3739 
3740     auto ModuleId = ModuleIdMap.size();
3741     ModuleIdMap[Key] = ModuleId;
3742     Vals.push_back(ModuleId);
3743     Vals.append(Key.begin(), Key.end());
3744 
3745     // Emit the finished record.
3746     Stream.EmitRecord(bitc::MST_CODE_ENTRY, Vals, AbbrevToUse);
3747 
3748     // Emit an optional hash for the module now
3749     if (llvm::any_of(Hash, [](uint32_t H) { return H; })) {
3750       Vals.assign(Hash.begin(), Hash.end());
3751       // Emit the hash record.
3752       Stream.EmitRecord(bitc::MST_CODE_HASH, Vals, AbbrevHash);
3753     }
3754 
3755     Vals.clear();
3756   });
3757   Stream.ExitBlock();
3758 }
3759 
3760 /// Write the function type metadata related records that need to appear before
3761 /// a function summary entry (whether per-module or combined).
3762 template <typename Fn>
3763 static void writeFunctionTypeMetadataRecords(BitstreamWriter &Stream,
3764                                              FunctionSummary *FS,
3765                                              Fn GetValueID) {
3766   if (!FS->type_tests().empty())
3767     Stream.EmitRecord(bitc::FS_TYPE_TESTS, FS->type_tests());
3768 
3769   SmallVector<uint64_t, 64> Record;
3770 
3771   auto WriteVFuncIdVec = [&](uint64_t Ty,
3772                              ArrayRef<FunctionSummary::VFuncId> VFs) {
3773     if (VFs.empty())
3774       return;
3775     Record.clear();
3776     for (auto &VF : VFs) {
3777       Record.push_back(VF.GUID);
3778       Record.push_back(VF.Offset);
3779     }
3780     Stream.EmitRecord(Ty, Record);
3781   };
3782 
3783   WriteVFuncIdVec(bitc::FS_TYPE_TEST_ASSUME_VCALLS,
3784                   FS->type_test_assume_vcalls());
3785   WriteVFuncIdVec(bitc::FS_TYPE_CHECKED_LOAD_VCALLS,
3786                   FS->type_checked_load_vcalls());
3787 
3788   auto WriteConstVCallVec = [&](uint64_t Ty,
3789                                 ArrayRef<FunctionSummary::ConstVCall> VCs) {
3790     for (auto &VC : VCs) {
3791       Record.clear();
3792       Record.push_back(VC.VFunc.GUID);
3793       Record.push_back(VC.VFunc.Offset);
3794       llvm::append_range(Record, VC.Args);
3795       Stream.EmitRecord(Ty, Record);
3796     }
3797   };
3798 
3799   WriteConstVCallVec(bitc::FS_TYPE_TEST_ASSUME_CONST_VCALL,
3800                      FS->type_test_assume_const_vcalls());
3801   WriteConstVCallVec(bitc::FS_TYPE_CHECKED_LOAD_CONST_VCALL,
3802                      FS->type_checked_load_const_vcalls());
3803 
3804   auto WriteRange = [&](ConstantRange Range) {
3805     Range = Range.sextOrTrunc(FunctionSummary::ParamAccess::RangeWidth);
3806     assert(Range.getLower().getNumWords() == 1);
3807     assert(Range.getUpper().getNumWords() == 1);
3808     emitSignedInt64(Record, *Range.getLower().getRawData());
3809     emitSignedInt64(Record, *Range.getUpper().getRawData());
3810   };
3811 
3812   if (!FS->paramAccesses().empty()) {
3813     Record.clear();
3814     for (auto &Arg : FS->paramAccesses()) {
3815       size_t UndoSize = Record.size();
3816       Record.push_back(Arg.ParamNo);
3817       WriteRange(Arg.Use);
3818       Record.push_back(Arg.Calls.size());
3819       for (auto &Call : Arg.Calls) {
3820         Record.push_back(Call.ParamNo);
3821         std::optional<unsigned> ValueID = GetValueID(Call.Callee);
3822         if (!ValueID) {
3823           // If ValueID is unknown we can't drop just this call, we must drop
3824           // entire parameter.
3825           Record.resize(UndoSize);
3826           break;
3827         }
3828         Record.push_back(*ValueID);
3829         WriteRange(Call.Offsets);
3830       }
3831     }
3832     if (!Record.empty())
3833       Stream.EmitRecord(bitc::FS_PARAM_ACCESS, Record);
3834   }
3835 }
3836 
3837 /// Collect type IDs from type tests used by function.
3838 static void
3839 getReferencedTypeIds(FunctionSummary *FS,
3840                      std::set<GlobalValue::GUID> &ReferencedTypeIds) {
3841   if (!FS->type_tests().empty())
3842     for (auto &TT : FS->type_tests())
3843       ReferencedTypeIds.insert(TT);
3844 
3845   auto GetReferencedTypesFromVFuncIdVec =
3846       [&](ArrayRef<FunctionSummary::VFuncId> VFs) {
3847         for (auto &VF : VFs)
3848           ReferencedTypeIds.insert(VF.GUID);
3849       };
3850 
3851   GetReferencedTypesFromVFuncIdVec(FS->type_test_assume_vcalls());
3852   GetReferencedTypesFromVFuncIdVec(FS->type_checked_load_vcalls());
3853 
3854   auto GetReferencedTypesFromConstVCallVec =
3855       [&](ArrayRef<FunctionSummary::ConstVCall> VCs) {
3856         for (auto &VC : VCs)
3857           ReferencedTypeIds.insert(VC.VFunc.GUID);
3858       };
3859 
3860   GetReferencedTypesFromConstVCallVec(FS->type_test_assume_const_vcalls());
3861   GetReferencedTypesFromConstVCallVec(FS->type_checked_load_const_vcalls());
3862 }
3863 
3864 static void writeWholeProgramDevirtResolutionByArg(
3865     SmallVector<uint64_t, 64> &NameVals, const std::vector<uint64_t> &args,
3866     const WholeProgramDevirtResolution::ByArg &ByArg) {
3867   NameVals.push_back(args.size());
3868   llvm::append_range(NameVals, args);
3869 
3870   NameVals.push_back(ByArg.TheKind);
3871   NameVals.push_back(ByArg.Info);
3872   NameVals.push_back(ByArg.Byte);
3873   NameVals.push_back(ByArg.Bit);
3874 }
3875 
3876 static void writeWholeProgramDevirtResolution(
3877     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3878     uint64_t Id, const WholeProgramDevirtResolution &Wpd) {
3879   NameVals.push_back(Id);
3880 
3881   NameVals.push_back(Wpd.TheKind);
3882   NameVals.push_back(StrtabBuilder.add(Wpd.SingleImplName));
3883   NameVals.push_back(Wpd.SingleImplName.size());
3884 
3885   NameVals.push_back(Wpd.ResByArg.size());
3886   for (auto &A : Wpd.ResByArg)
3887     writeWholeProgramDevirtResolutionByArg(NameVals, A.first, A.second);
3888 }
3889 
3890 static void writeTypeIdSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
3891                                      StringTableBuilder &StrtabBuilder,
3892                                      const std::string &Id,
3893                                      const TypeIdSummary &Summary) {
3894   NameVals.push_back(StrtabBuilder.add(Id));
3895   NameVals.push_back(Id.size());
3896 
3897   NameVals.push_back(Summary.TTRes.TheKind);
3898   NameVals.push_back(Summary.TTRes.SizeM1BitWidth);
3899   NameVals.push_back(Summary.TTRes.AlignLog2);
3900   NameVals.push_back(Summary.TTRes.SizeM1);
3901   NameVals.push_back(Summary.TTRes.BitMask);
3902   NameVals.push_back(Summary.TTRes.InlineBits);
3903 
3904   for (auto &W : Summary.WPDRes)
3905     writeWholeProgramDevirtResolution(NameVals, StrtabBuilder, W.first,
3906                                       W.second);
3907 }
3908 
3909 static void writeTypeIdCompatibleVtableSummaryRecord(
3910     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3911     const std::string &Id, const TypeIdCompatibleVtableInfo &Summary,
3912     ValueEnumerator &VE) {
3913   NameVals.push_back(StrtabBuilder.add(Id));
3914   NameVals.push_back(Id.size());
3915 
3916   for (auto &P : Summary) {
3917     NameVals.push_back(P.AddressPointOffset);
3918     NameVals.push_back(VE.getValueID(P.VTableVI.getValue()));
3919   }
3920 }
3921 
3922 static void writeFunctionHeapProfileRecords(
3923     BitstreamWriter &Stream, FunctionSummary *FS, unsigned CallsiteAbbrev,
3924     unsigned AllocAbbrev, bool PerModule,
3925     std::function<unsigned(const ValueInfo &VI)> GetValueID,
3926     std::function<unsigned(unsigned)> GetStackIndex) {
3927   SmallVector<uint64_t> Record;
3928 
3929   for (auto &CI : FS->callsites()) {
3930     Record.clear();
3931     // Per module callsite clones should always have a single entry of
3932     // value 0.
3933     assert(!PerModule || (CI.Clones.size() == 1 && CI.Clones[0] == 0));
3934     Record.push_back(GetValueID(CI.Callee));
3935     if (!PerModule) {
3936       Record.push_back(CI.StackIdIndices.size());
3937       Record.push_back(CI.Clones.size());
3938     }
3939     for (auto Id : CI.StackIdIndices)
3940       Record.push_back(GetStackIndex(Id));
3941     if (!PerModule) {
3942       for (auto V : CI.Clones)
3943         Record.push_back(V);
3944     }
3945     Stream.EmitRecord(PerModule ? bitc::FS_PERMODULE_CALLSITE_INFO
3946                                 : bitc::FS_COMBINED_CALLSITE_INFO,
3947                       Record, CallsiteAbbrev);
3948   }
3949 
3950   for (auto &AI : FS->allocs()) {
3951     Record.clear();
3952     // Per module alloc versions should always have a single entry of
3953     // value 0.
3954     assert(!PerModule || (AI.Versions.size() == 1 && AI.Versions[0] == 0));
3955     if (!PerModule) {
3956       Record.push_back(AI.MIBs.size());
3957       Record.push_back(AI.Versions.size());
3958     }
3959     for (auto &MIB : AI.MIBs) {
3960       Record.push_back((uint8_t)MIB.AllocType);
3961       Record.push_back(MIB.StackIdIndices.size());
3962       for (auto Id : MIB.StackIdIndices)
3963         Record.push_back(GetStackIndex(Id));
3964     }
3965     if (!PerModule) {
3966       for (auto V : AI.Versions)
3967         Record.push_back(V);
3968     }
3969     Stream.EmitRecord(PerModule ? bitc::FS_PERMODULE_ALLOC_INFO
3970                                 : bitc::FS_COMBINED_ALLOC_INFO,
3971                       Record, AllocAbbrev);
3972   }
3973 }
3974 
3975 // Helper to emit a single function summary record.
3976 void ModuleBitcodeWriterBase::writePerModuleFunctionSummaryRecord(
3977     SmallVector<uint64_t, 64> &NameVals, GlobalValueSummary *Summary,
3978     unsigned ValueID, unsigned FSCallsAbbrev, unsigned FSCallsProfileAbbrev,
3979     unsigned CallsiteAbbrev, unsigned AllocAbbrev, const Function &F) {
3980   NameVals.push_back(ValueID);
3981 
3982   FunctionSummary *FS = cast<FunctionSummary>(Summary);
3983 
3984   writeFunctionTypeMetadataRecords(
3985       Stream, FS, [&](const ValueInfo &VI) -> std::optional<unsigned> {
3986         return {VE.getValueID(VI.getValue())};
3987       });
3988 
3989   writeFunctionHeapProfileRecords(
3990       Stream, FS, CallsiteAbbrev, AllocAbbrev,
3991       /*PerModule*/ true,
3992       /*GetValueId*/ [&](const ValueInfo &VI) { return getValueId(VI); },
3993       /*GetStackIndex*/ [&](unsigned I) { return I; });
3994 
3995   auto SpecialRefCnts = FS->specialRefCounts();
3996   NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
3997   NameVals.push_back(FS->instCount());
3998   NameVals.push_back(getEncodedFFlags(FS->fflags()));
3999   NameVals.push_back(FS->refs().size());
4000   NameVals.push_back(SpecialRefCnts.first);  // rorefcnt
4001   NameVals.push_back(SpecialRefCnts.second); // worefcnt
4002 
4003   for (auto &RI : FS->refs())
4004     NameVals.push_back(VE.getValueID(RI.getValue()));
4005 
4006   bool HasProfileData =
4007       F.hasProfileData() || ForceSummaryEdgesCold != FunctionSummary::FSHT_None;
4008   for (auto &ECI : FS->calls()) {
4009     NameVals.push_back(getValueId(ECI.first));
4010     if (HasProfileData)
4011       NameVals.push_back(static_cast<uint8_t>(ECI.second.Hotness));
4012     else if (WriteRelBFToSummary)
4013       NameVals.push_back(ECI.second.RelBlockFreq);
4014   }
4015 
4016   unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
4017   unsigned Code =
4018       (HasProfileData ? bitc::FS_PERMODULE_PROFILE
4019                       : (WriteRelBFToSummary ? bitc::FS_PERMODULE_RELBF
4020                                              : bitc::FS_PERMODULE));
4021 
4022   // Emit the finished record.
4023   Stream.EmitRecord(Code, NameVals, FSAbbrev);
4024   NameVals.clear();
4025 }
4026 
4027 // Collect the global value references in the given variable's initializer,
4028 // and emit them in a summary record.
4029 void ModuleBitcodeWriterBase::writeModuleLevelReferences(
4030     const GlobalVariable &V, SmallVector<uint64_t, 64> &NameVals,
4031     unsigned FSModRefsAbbrev, unsigned FSModVTableRefsAbbrev) {
4032   auto VI = Index->getValueInfo(V.getGUID());
4033   if (!VI || VI.getSummaryList().empty()) {
4034     // Only declarations should not have a summary (a declaration might however
4035     // have a summary if the def was in module level asm).
4036     assert(V.isDeclaration());
4037     return;
4038   }
4039   auto *Summary = VI.getSummaryList()[0].get();
4040   NameVals.push_back(VE.getValueID(&V));
4041   GlobalVarSummary *VS = cast<GlobalVarSummary>(Summary);
4042   NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
4043   NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
4044 
4045   auto VTableFuncs = VS->vTableFuncs();
4046   if (!VTableFuncs.empty())
4047     NameVals.push_back(VS->refs().size());
4048 
4049   unsigned SizeBeforeRefs = NameVals.size();
4050   for (auto &RI : VS->refs())
4051     NameVals.push_back(VE.getValueID(RI.getValue()));
4052   // Sort the refs for determinism output, the vector returned by FS->refs() has
4053   // been initialized from a DenseSet.
4054   llvm::sort(drop_begin(NameVals, SizeBeforeRefs));
4055 
4056   if (VTableFuncs.empty())
4057     Stream.EmitRecord(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS, NameVals,
4058                       FSModRefsAbbrev);
4059   else {
4060     // VTableFuncs pairs should already be sorted by offset.
4061     for (auto &P : VTableFuncs) {
4062       NameVals.push_back(VE.getValueID(P.FuncVI.getValue()));
4063       NameVals.push_back(P.VTableOffset);
4064     }
4065 
4066     Stream.EmitRecord(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS, NameVals,
4067                       FSModVTableRefsAbbrev);
4068   }
4069   NameVals.clear();
4070 }
4071 
4072 /// Emit the per-module summary section alongside the rest of
4073 /// the module's bitcode.
4074 void ModuleBitcodeWriterBase::writePerModuleGlobalValueSummary() {
4075   // By default we compile with ThinLTO if the module has a summary, but the
4076   // client can request full LTO with a module flag.
4077   bool IsThinLTO = true;
4078   if (auto *MD =
4079           mdconst::extract_or_null<ConstantInt>(M.getModuleFlag("ThinLTO")))
4080     IsThinLTO = MD->getZExtValue();
4081   Stream.EnterSubblock(IsThinLTO ? bitc::GLOBALVAL_SUMMARY_BLOCK_ID
4082                                  : bitc::FULL_LTO_GLOBALVAL_SUMMARY_BLOCK_ID,
4083                        4);
4084 
4085   Stream.EmitRecord(
4086       bitc::FS_VERSION,
4087       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
4088 
4089   // Write the index flags.
4090   uint64_t Flags = 0;
4091   // Bits 1-3 are set only in the combined index, skip them.
4092   if (Index->enableSplitLTOUnit())
4093     Flags |= 0x8;
4094   if (Index->hasUnifiedLTO())
4095     Flags |= 0x200;
4096 
4097   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Flags});
4098 
4099   if (Index->begin() == Index->end()) {
4100     Stream.ExitBlock();
4101     return;
4102   }
4103 
4104   for (const auto &GVI : valueIds()) {
4105     Stream.EmitRecord(bitc::FS_VALUE_GUID,
4106                       ArrayRef<uint64_t>{GVI.second, GVI.first});
4107   }
4108 
4109   if (!Index->stackIds().empty()) {
4110     auto StackIdAbbv = std::make_shared<BitCodeAbbrev>();
4111     StackIdAbbv->Add(BitCodeAbbrevOp(bitc::FS_STACK_IDS));
4112     // numids x stackid
4113     StackIdAbbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4114     StackIdAbbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4115     unsigned StackIdAbbvId = Stream.EmitAbbrev(std::move(StackIdAbbv));
4116     Stream.EmitRecord(bitc::FS_STACK_IDS, Index->stackIds(), StackIdAbbvId);
4117   }
4118 
4119   // Abbrev for FS_PERMODULE_PROFILE.
4120   auto Abbv = std::make_shared<BitCodeAbbrev>();
4121   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_PROFILE));
4122   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4123   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // flags
4124   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4125   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4126   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4127   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4128   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4129   // numrefs x valueid, n x (valueid, hotness)
4130   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4131   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4132   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4133 
4134   // Abbrev for FS_PERMODULE or FS_PERMODULE_RELBF.
4135   Abbv = std::make_shared<BitCodeAbbrev>();
4136   if (WriteRelBFToSummary)
4137     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_RELBF));
4138   else
4139     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE));
4140   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4141   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4142   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4143   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4144   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4145   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4146   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4147   // numrefs x valueid, n x (valueid [, rel_block_freq])
4148   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4149   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4150   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4151 
4152   // Abbrev for FS_PERMODULE_GLOBALVAR_INIT_REFS.
4153   Abbv = std::make_shared<BitCodeAbbrev>();
4154   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS));
4155   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
4156   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
4157   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));  // valueids
4158   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4159   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4160 
4161   // Abbrev for FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS.
4162   Abbv = std::make_shared<BitCodeAbbrev>();
4163   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS));
4164   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
4165   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
4166   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numrefs
4167   // numrefs x valueid, n x (valueid , offset)
4168   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4169   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4170   unsigned FSModVTableRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4171 
4172   // Abbrev for FS_ALIAS.
4173   Abbv = std::make_shared<BitCodeAbbrev>();
4174   Abbv->Add(BitCodeAbbrevOp(bitc::FS_ALIAS));
4175   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4176   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4177   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4178   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4179 
4180   // Abbrev for FS_TYPE_ID_METADATA
4181   Abbv = std::make_shared<BitCodeAbbrev>();
4182   Abbv->Add(BitCodeAbbrevOp(bitc::FS_TYPE_ID_METADATA));
4183   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid strtab index
4184   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid length
4185   // n x (valueid , offset)
4186   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4187   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4188   unsigned TypeIdCompatibleVtableAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4189 
4190   Abbv = std::make_shared<BitCodeAbbrev>();
4191   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_CALLSITE_INFO));
4192   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
4193   // n x stackidindex
4194   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4195   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4196   unsigned CallsiteAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4197 
4198   Abbv = std::make_shared<BitCodeAbbrev>();
4199   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_ALLOC_INFO));
4200   // n x (alloc type, numstackids, numstackids x stackidindex)
4201   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4202   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4203   unsigned AllocAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4204 
4205   SmallVector<uint64_t, 64> NameVals;
4206   // Iterate over the list of functions instead of the Index to
4207   // ensure the ordering is stable.
4208   for (const Function &F : M) {
4209     // Summary emission does not support anonymous functions, they have to
4210     // renamed using the anonymous function renaming pass.
4211     if (!F.hasName())
4212       report_fatal_error("Unexpected anonymous function when writing summary");
4213 
4214     ValueInfo VI = Index->getValueInfo(F.getGUID());
4215     if (!VI || VI.getSummaryList().empty()) {
4216       // Only declarations should not have a summary (a declaration might
4217       // however have a summary if the def was in module level asm).
4218       assert(F.isDeclaration());
4219       continue;
4220     }
4221     auto *Summary = VI.getSummaryList()[0].get();
4222     writePerModuleFunctionSummaryRecord(NameVals, Summary, VE.getValueID(&F),
4223                                         FSCallsAbbrev, FSCallsProfileAbbrev,
4224                                         CallsiteAbbrev, AllocAbbrev, F);
4225   }
4226 
4227   // Capture references from GlobalVariable initializers, which are outside
4228   // of a function scope.
4229   for (const GlobalVariable &G : M.globals())
4230     writeModuleLevelReferences(G, NameVals, FSModRefsAbbrev,
4231                                FSModVTableRefsAbbrev);
4232 
4233   for (const GlobalAlias &A : M.aliases()) {
4234     auto *Aliasee = A.getAliaseeObject();
4235     // Skip ifunc and nameless functions which don't have an entry in the
4236     // summary.
4237     if (!Aliasee->hasName() || isa<GlobalIFunc>(Aliasee))
4238       continue;
4239     auto AliasId = VE.getValueID(&A);
4240     auto AliaseeId = VE.getValueID(Aliasee);
4241     NameVals.push_back(AliasId);
4242     auto *Summary = Index->getGlobalValueSummary(A);
4243     AliasSummary *AS = cast<AliasSummary>(Summary);
4244     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
4245     NameVals.push_back(AliaseeId);
4246     Stream.EmitRecord(bitc::FS_ALIAS, NameVals, FSAliasAbbrev);
4247     NameVals.clear();
4248   }
4249 
4250   for (auto &S : Index->typeIdCompatibleVtableMap()) {
4251     writeTypeIdCompatibleVtableSummaryRecord(NameVals, StrtabBuilder, S.first,
4252                                              S.second, VE);
4253     Stream.EmitRecord(bitc::FS_TYPE_ID_METADATA, NameVals,
4254                       TypeIdCompatibleVtableAbbrev);
4255     NameVals.clear();
4256   }
4257 
4258   if (Index->getBlockCount())
4259     Stream.EmitRecord(bitc::FS_BLOCK_COUNT,
4260                       ArrayRef<uint64_t>{Index->getBlockCount()});
4261 
4262   Stream.ExitBlock();
4263 }
4264 
4265 /// Emit the combined summary section into the combined index file.
4266 void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
4267   Stream.EnterSubblock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID, 4);
4268   Stream.EmitRecord(
4269       bitc::FS_VERSION,
4270       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
4271 
4272   // Write the index flags.
4273   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Index.getFlags()});
4274 
4275   for (const auto &GVI : valueIds()) {
4276     Stream.EmitRecord(bitc::FS_VALUE_GUID,
4277                       ArrayRef<uint64_t>{GVI.second, GVI.first});
4278   }
4279 
4280   if (!StackIdIndices.empty()) {
4281     auto StackIdAbbv = std::make_shared<BitCodeAbbrev>();
4282     StackIdAbbv->Add(BitCodeAbbrevOp(bitc::FS_STACK_IDS));
4283     // numids x stackid
4284     StackIdAbbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4285     StackIdAbbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4286     unsigned StackIdAbbvId = Stream.EmitAbbrev(std::move(StackIdAbbv));
4287     // Write the stack ids used by this index, which will be a subset of those in
4288     // the full index in the case of distributed indexes.
4289     std::vector<uint64_t> StackIds;
4290     for (auto &I : StackIdIndices)
4291       StackIds.push_back(Index.getStackIdAtIndex(I));
4292     Stream.EmitRecord(bitc::FS_STACK_IDS, StackIds, StackIdAbbvId);
4293   }
4294 
4295   // Abbrev for FS_COMBINED.
4296   auto Abbv = std::make_shared<BitCodeAbbrev>();
4297   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED));
4298   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4299   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4300   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4301   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4302   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4303   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
4304   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4305   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4306   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4307   // numrefs x valueid, n x (valueid)
4308   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4309   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4310   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4311 
4312   // Abbrev for FS_COMBINED_PROFILE.
4313   Abbv = std::make_shared<BitCodeAbbrev>();
4314   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_PROFILE));
4315   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4316   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4317   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4318   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4319   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4320   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
4321   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4322   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4323   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4324   // numrefs x valueid, n x (valueid, hotness)
4325   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4326   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4327   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4328 
4329   // Abbrev for FS_COMBINED_GLOBALVAR_INIT_REFS.
4330   Abbv = std::make_shared<BitCodeAbbrev>();
4331   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS));
4332   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4333   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4334   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4335   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));    // valueids
4336   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4337   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4338 
4339   // Abbrev for FS_COMBINED_ALIAS.
4340   Abbv = std::make_shared<BitCodeAbbrev>();
4341   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_ALIAS));
4342   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4343   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4344   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4345   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4346   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4347 
4348   Abbv = std::make_shared<BitCodeAbbrev>();
4349   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_CALLSITE_INFO));
4350   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
4351   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numstackindices
4352   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numver
4353   // numstackindices x stackidindex, numver x version
4354   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4355   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4356   unsigned CallsiteAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4357 
4358   Abbv = std::make_shared<BitCodeAbbrev>();
4359   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_ALLOC_INFO));
4360   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // nummib
4361   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numver
4362   // nummib x (alloc type, numstackids, numstackids x stackidindex),
4363   // numver x version
4364   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4365   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4366   unsigned AllocAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4367 
4368   // The aliases are emitted as a post-pass, and will point to the value
4369   // id of the aliasee. Save them in a vector for post-processing.
4370   SmallVector<AliasSummary *, 64> Aliases;
4371 
4372   // Save the value id for each summary for alias emission.
4373   DenseMap<const GlobalValueSummary *, unsigned> SummaryToValueIdMap;
4374 
4375   SmallVector<uint64_t, 64> NameVals;
4376 
4377   // Set that will be populated during call to writeFunctionTypeMetadataRecords
4378   // with the type ids referenced by this index file.
4379   std::set<GlobalValue::GUID> ReferencedTypeIds;
4380 
4381   // For local linkage, we also emit the original name separately
4382   // immediately after the record.
4383   auto MaybeEmitOriginalName = [&](GlobalValueSummary &S) {
4384     // We don't need to emit the original name if we are writing the index for
4385     // distributed backends (in which case ModuleToSummariesForIndex is
4386     // non-null). The original name is only needed during the thin link, since
4387     // for SamplePGO the indirect call targets for local functions have
4388     // have the original name annotated in profile.
4389     // Continue to emit it when writing out the entire combined index, which is
4390     // used in testing the thin link via llvm-lto.
4391     if (ModuleToSummariesForIndex || !GlobalValue::isLocalLinkage(S.linkage()))
4392       return;
4393     NameVals.push_back(S.getOriginalName());
4394     Stream.EmitRecord(bitc::FS_COMBINED_ORIGINAL_NAME, NameVals);
4395     NameVals.clear();
4396   };
4397 
4398   std::set<GlobalValue::GUID> DefOrUseGUIDs;
4399   forEachSummary([&](GVInfo I, bool IsAliasee) {
4400     GlobalValueSummary *S = I.second;
4401     assert(S);
4402     DefOrUseGUIDs.insert(I.first);
4403     for (const ValueInfo &VI : S->refs())
4404       DefOrUseGUIDs.insert(VI.getGUID());
4405 
4406     auto ValueId = getValueId(I.first);
4407     assert(ValueId);
4408     SummaryToValueIdMap[S] = *ValueId;
4409 
4410     // If this is invoked for an aliasee, we want to record the above
4411     // mapping, but then not emit a summary entry (if the aliasee is
4412     // to be imported, we will invoke this separately with IsAliasee=false).
4413     if (IsAliasee)
4414       return;
4415 
4416     if (auto *AS = dyn_cast<AliasSummary>(S)) {
4417       // Will process aliases as a post-pass because the reader wants all
4418       // global to be loaded first.
4419       Aliases.push_back(AS);
4420       return;
4421     }
4422 
4423     if (auto *VS = dyn_cast<GlobalVarSummary>(S)) {
4424       NameVals.push_back(*ValueId);
4425       assert(ModuleIdMap.count(VS->modulePath()));
4426       NameVals.push_back(ModuleIdMap[VS->modulePath()]);
4427       NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
4428       NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
4429       for (auto &RI : VS->refs()) {
4430         auto RefValueId = getValueId(RI.getGUID());
4431         if (!RefValueId)
4432           continue;
4433         NameVals.push_back(*RefValueId);
4434       }
4435 
4436       // Emit the finished record.
4437       Stream.EmitRecord(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS, NameVals,
4438                         FSModRefsAbbrev);
4439       NameVals.clear();
4440       MaybeEmitOriginalName(*S);
4441       return;
4442     }
4443 
4444     auto GetValueId = [&](const ValueInfo &VI) -> std::optional<unsigned> {
4445       if (!VI)
4446         return std::nullopt;
4447       return getValueId(VI.getGUID());
4448     };
4449 
4450     auto *FS = cast<FunctionSummary>(S);
4451     writeFunctionTypeMetadataRecords(Stream, FS, GetValueId);
4452     getReferencedTypeIds(FS, ReferencedTypeIds);
4453 
4454     writeFunctionHeapProfileRecords(
4455         Stream, FS, CallsiteAbbrev, AllocAbbrev,
4456         /*PerModule*/ false,
4457         /*GetValueId*/ [&](const ValueInfo &VI) -> unsigned {
4458           std::optional<unsigned> ValueID = GetValueId(VI);
4459           // This can happen in shared index files for distributed ThinLTO if
4460           // the callee function summary is not included. Record 0 which we
4461           // will have to deal with conservatively when doing any kind of
4462           // validation in the ThinLTO backends.
4463           if (!ValueID)
4464             return 0;
4465           return *ValueID;
4466         },
4467         /*GetStackIndex*/ [&](unsigned I) {
4468           // Get the corresponding index into the list of StackIdIndices
4469           // actually being written for this combined index (which may be a
4470           // subset in the case of distributed indexes).
4471           auto Lower = llvm::lower_bound(StackIdIndices, I);
4472           return std::distance(StackIdIndices.begin(), Lower);
4473         });
4474 
4475     NameVals.push_back(*ValueId);
4476     assert(ModuleIdMap.count(FS->modulePath()));
4477     NameVals.push_back(ModuleIdMap[FS->modulePath()]);
4478     NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
4479     NameVals.push_back(FS->instCount());
4480     NameVals.push_back(getEncodedFFlags(FS->fflags()));
4481     NameVals.push_back(FS->entryCount());
4482 
4483     // Fill in below
4484     NameVals.push_back(0); // numrefs
4485     NameVals.push_back(0); // rorefcnt
4486     NameVals.push_back(0); // worefcnt
4487 
4488     unsigned Count = 0, RORefCnt = 0, WORefCnt = 0;
4489     for (auto &RI : FS->refs()) {
4490       auto RefValueId = getValueId(RI.getGUID());
4491       if (!RefValueId)
4492         continue;
4493       NameVals.push_back(*RefValueId);
4494       if (RI.isReadOnly())
4495         RORefCnt++;
4496       else if (RI.isWriteOnly())
4497         WORefCnt++;
4498       Count++;
4499     }
4500     NameVals[6] = Count;
4501     NameVals[7] = RORefCnt;
4502     NameVals[8] = WORefCnt;
4503 
4504     bool HasProfileData = false;
4505     for (auto &EI : FS->calls()) {
4506       HasProfileData |=
4507           EI.second.getHotness() != CalleeInfo::HotnessType::Unknown;
4508       if (HasProfileData)
4509         break;
4510     }
4511 
4512     for (auto &EI : FS->calls()) {
4513       // If this GUID doesn't have a value id, it doesn't have a function
4514       // summary and we don't need to record any calls to it.
4515       std::optional<unsigned> CallValueId = GetValueId(EI.first);
4516       if (!CallValueId)
4517         continue;
4518       NameVals.push_back(*CallValueId);
4519       if (HasProfileData)
4520         NameVals.push_back(static_cast<uint8_t>(EI.second.Hotness));
4521     }
4522 
4523     unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
4524     unsigned Code =
4525         (HasProfileData ? bitc::FS_COMBINED_PROFILE : bitc::FS_COMBINED);
4526 
4527     // Emit the finished record.
4528     Stream.EmitRecord(Code, NameVals, FSAbbrev);
4529     NameVals.clear();
4530     MaybeEmitOriginalName(*S);
4531   });
4532 
4533   for (auto *AS : Aliases) {
4534     auto AliasValueId = SummaryToValueIdMap[AS];
4535     assert(AliasValueId);
4536     NameVals.push_back(AliasValueId);
4537     assert(ModuleIdMap.count(AS->modulePath()));
4538     NameVals.push_back(ModuleIdMap[AS->modulePath()]);
4539     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
4540     auto AliaseeValueId = SummaryToValueIdMap[&AS->getAliasee()];
4541     assert(AliaseeValueId);
4542     NameVals.push_back(AliaseeValueId);
4543 
4544     // Emit the finished record.
4545     Stream.EmitRecord(bitc::FS_COMBINED_ALIAS, NameVals, FSAliasAbbrev);
4546     NameVals.clear();
4547     MaybeEmitOriginalName(*AS);
4548 
4549     if (auto *FS = dyn_cast<FunctionSummary>(&AS->getAliasee()))
4550       getReferencedTypeIds(FS, ReferencedTypeIds);
4551   }
4552 
4553   if (!Index.cfiFunctionDefs().empty()) {
4554     for (auto &S : Index.cfiFunctionDefs()) {
4555       if (DefOrUseGUIDs.count(
4556               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4557         NameVals.push_back(StrtabBuilder.add(S));
4558         NameVals.push_back(S.size());
4559       }
4560     }
4561     if (!NameVals.empty()) {
4562       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DEFS, NameVals);
4563       NameVals.clear();
4564     }
4565   }
4566 
4567   if (!Index.cfiFunctionDecls().empty()) {
4568     for (auto &S : Index.cfiFunctionDecls()) {
4569       if (DefOrUseGUIDs.count(
4570               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4571         NameVals.push_back(StrtabBuilder.add(S));
4572         NameVals.push_back(S.size());
4573       }
4574     }
4575     if (!NameVals.empty()) {
4576       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DECLS, NameVals);
4577       NameVals.clear();
4578     }
4579   }
4580 
4581   // Walk the GUIDs that were referenced, and write the
4582   // corresponding type id records.
4583   for (auto &T : ReferencedTypeIds) {
4584     auto TidIter = Index.typeIds().equal_range(T);
4585     for (auto It = TidIter.first; It != TidIter.second; ++It) {
4586       writeTypeIdSummaryRecord(NameVals, StrtabBuilder, It->second.first,
4587                                It->second.second);
4588       Stream.EmitRecord(bitc::FS_TYPE_ID, NameVals);
4589       NameVals.clear();
4590     }
4591   }
4592 
4593   if (Index.getBlockCount())
4594     Stream.EmitRecord(bitc::FS_BLOCK_COUNT,
4595                       ArrayRef<uint64_t>{Index.getBlockCount()});
4596 
4597   Stream.ExitBlock();
4598 }
4599 
4600 /// Create the "IDENTIFICATION_BLOCK_ID" containing a single string with the
4601 /// current llvm version, and a record for the epoch number.
4602 static void writeIdentificationBlock(BitstreamWriter &Stream) {
4603   Stream.EnterSubblock(bitc::IDENTIFICATION_BLOCK_ID, 5);
4604 
4605   // Write the "user readable" string identifying the bitcode producer
4606   auto Abbv = std::make_shared<BitCodeAbbrev>();
4607   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_STRING));
4608   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4609   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
4610   auto StringAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4611   writeStringRecord(Stream, bitc::IDENTIFICATION_CODE_STRING,
4612                     "LLVM" LLVM_VERSION_STRING, StringAbbrev);
4613 
4614   // Write the epoch version
4615   Abbv = std::make_shared<BitCodeAbbrev>();
4616   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_EPOCH));
4617   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
4618   auto EpochAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4619   constexpr std::array<unsigned, 1> Vals = {{bitc::BITCODE_CURRENT_EPOCH}};
4620   Stream.EmitRecord(bitc::IDENTIFICATION_CODE_EPOCH, Vals, EpochAbbrev);
4621   Stream.ExitBlock();
4622 }
4623 
4624 void ModuleBitcodeWriter::writeModuleHash(size_t BlockStartPos) {
4625   // Emit the module's hash.
4626   // MODULE_CODE_HASH: [5*i32]
4627   if (GenerateHash) {
4628     uint32_t Vals[5];
4629     Hasher.update(ArrayRef<uint8_t>((const uint8_t *)&(Buffer)[BlockStartPos],
4630                                     Buffer.size() - BlockStartPos));
4631     std::array<uint8_t, 20> Hash = Hasher.result();
4632     for (int Pos = 0; Pos < 20; Pos += 4) {
4633       Vals[Pos / 4] = support::endian::read32be(Hash.data() + Pos);
4634     }
4635 
4636     // Emit the finished record.
4637     Stream.EmitRecord(bitc::MODULE_CODE_HASH, Vals);
4638 
4639     if (ModHash)
4640       // Save the written hash value.
4641       llvm::copy(Vals, std::begin(*ModHash));
4642   }
4643 }
4644 
4645 void ModuleBitcodeWriter::write() {
4646   writeIdentificationBlock(Stream);
4647 
4648   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4649   size_t BlockStartPos = Buffer.size();
4650 
4651   writeModuleVersion();
4652 
4653   // Emit blockinfo, which defines the standard abbreviations etc.
4654   writeBlockInfo();
4655 
4656   // Emit information describing all of the types in the module.
4657   writeTypeTable();
4658 
4659   // Emit information about attribute groups.
4660   writeAttributeGroupTable();
4661 
4662   // Emit information about parameter attributes.
4663   writeAttributeTable();
4664 
4665   writeComdats();
4666 
4667   // Emit top-level description of module, including target triple, inline asm,
4668   // descriptors for global variables, and function prototype info.
4669   writeModuleInfo();
4670 
4671   // Emit constants.
4672   writeModuleConstants();
4673 
4674   // Emit metadata kind names.
4675   writeModuleMetadataKinds();
4676 
4677   // Emit metadata.
4678   writeModuleMetadata();
4679 
4680   // Emit module-level use-lists.
4681   if (VE.shouldPreserveUseListOrder())
4682     writeUseListBlock(nullptr);
4683 
4684   writeOperandBundleTags();
4685   writeSyncScopeNames();
4686 
4687   // Emit function bodies.
4688   DenseMap<const Function *, uint64_t> FunctionToBitcodeIndex;
4689   for (const Function &F : M)
4690     if (!F.isDeclaration())
4691       writeFunction(F, FunctionToBitcodeIndex);
4692 
4693   // Need to write after the above call to WriteFunction which populates
4694   // the summary information in the index.
4695   if (Index)
4696     writePerModuleGlobalValueSummary();
4697 
4698   writeGlobalValueSymbolTable(FunctionToBitcodeIndex);
4699 
4700   writeModuleHash(BlockStartPos);
4701 
4702   Stream.ExitBlock();
4703 }
4704 
4705 static void writeInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
4706                                uint32_t &Position) {
4707   support::endian::write32le(&Buffer[Position], Value);
4708   Position += 4;
4709 }
4710 
4711 /// If generating a bc file on darwin, we have to emit a
4712 /// header and trailer to make it compatible with the system archiver.  To do
4713 /// this we emit the following header, and then emit a trailer that pads the
4714 /// file out to be a multiple of 16 bytes.
4715 ///
4716 /// struct bc_header {
4717 ///   uint32_t Magic;         // 0x0B17C0DE
4718 ///   uint32_t Version;       // Version, currently always 0.
4719 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
4720 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
4721 ///   uint32_t CPUType;       // CPU specifier.
4722 ///   ... potentially more later ...
4723 /// };
4724 static void emitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
4725                                          const Triple &TT) {
4726   unsigned CPUType = ~0U;
4727 
4728   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
4729   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
4730   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
4731   // specific constants here because they are implicitly part of the Darwin ABI.
4732   enum {
4733     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
4734     DARWIN_CPU_TYPE_X86        = 7,
4735     DARWIN_CPU_TYPE_ARM        = 12,
4736     DARWIN_CPU_TYPE_POWERPC    = 18
4737   };
4738 
4739   Triple::ArchType Arch = TT.getArch();
4740   if (Arch == Triple::x86_64)
4741     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
4742   else if (Arch == Triple::x86)
4743     CPUType = DARWIN_CPU_TYPE_X86;
4744   else if (Arch == Triple::ppc)
4745     CPUType = DARWIN_CPU_TYPE_POWERPC;
4746   else if (Arch == Triple::ppc64)
4747     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
4748   else if (Arch == Triple::arm || Arch == Triple::thumb)
4749     CPUType = DARWIN_CPU_TYPE_ARM;
4750 
4751   // Traditional Bitcode starts after header.
4752   assert(Buffer.size() >= BWH_HeaderSize &&
4753          "Expected header size to be reserved");
4754   unsigned BCOffset = BWH_HeaderSize;
4755   unsigned BCSize = Buffer.size() - BWH_HeaderSize;
4756 
4757   // Write the magic and version.
4758   unsigned Position = 0;
4759   writeInt32ToBuffer(0x0B17C0DE, Buffer, Position);
4760   writeInt32ToBuffer(0, Buffer, Position); // Version.
4761   writeInt32ToBuffer(BCOffset, Buffer, Position);
4762   writeInt32ToBuffer(BCSize, Buffer, Position);
4763   writeInt32ToBuffer(CPUType, Buffer, Position);
4764 
4765   // If the file is not a multiple of 16 bytes, insert dummy padding.
4766   while (Buffer.size() & 15)
4767     Buffer.push_back(0);
4768 }
4769 
4770 /// Helper to write the header common to all bitcode files.
4771 static void writeBitcodeHeader(BitstreamWriter &Stream) {
4772   // Emit the file header.
4773   Stream.Emit((unsigned)'B', 8);
4774   Stream.Emit((unsigned)'C', 8);
4775   Stream.Emit(0x0, 4);
4776   Stream.Emit(0xC, 4);
4777   Stream.Emit(0xE, 4);
4778   Stream.Emit(0xD, 4);
4779 }
4780 
4781 BitcodeWriter::BitcodeWriter(SmallVectorImpl<char> &Buffer, raw_fd_stream *FS)
4782     : Buffer(Buffer), Stream(new BitstreamWriter(Buffer, FS, FlushThreshold)) {
4783   writeBitcodeHeader(*Stream);
4784 }
4785 
4786 BitcodeWriter::~BitcodeWriter() { assert(WroteStrtab); }
4787 
4788 void BitcodeWriter::writeBlob(unsigned Block, unsigned Record, StringRef Blob) {
4789   Stream->EnterSubblock(Block, 3);
4790 
4791   auto Abbv = std::make_shared<BitCodeAbbrev>();
4792   Abbv->Add(BitCodeAbbrevOp(Record));
4793   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
4794   auto AbbrevNo = Stream->EmitAbbrev(std::move(Abbv));
4795 
4796   Stream->EmitRecordWithBlob(AbbrevNo, ArrayRef<uint64_t>{Record}, Blob);
4797 
4798   Stream->ExitBlock();
4799 }
4800 
4801 void BitcodeWriter::writeSymtab() {
4802   assert(!WroteStrtab && !WroteSymtab);
4803 
4804   // If any module has module-level inline asm, we will require a registered asm
4805   // parser for the target so that we can create an accurate symbol table for
4806   // the module.
4807   for (Module *M : Mods) {
4808     if (M->getModuleInlineAsm().empty())
4809       continue;
4810 
4811     std::string Err;
4812     const Triple TT(M->getTargetTriple());
4813     const Target *T = TargetRegistry::lookupTarget(TT.str(), Err);
4814     if (!T || !T->hasMCAsmParser())
4815       return;
4816   }
4817 
4818   WroteSymtab = true;
4819   SmallVector<char, 0> Symtab;
4820   // The irsymtab::build function may be unable to create a symbol table if the
4821   // module is malformed (e.g. it contains an invalid alias). Writing a symbol
4822   // table is not required for correctness, but we still want to be able to
4823   // write malformed modules to bitcode files, so swallow the error.
4824   if (Error E = irsymtab::build(Mods, Symtab, StrtabBuilder, Alloc)) {
4825     consumeError(std::move(E));
4826     return;
4827   }
4828 
4829   writeBlob(bitc::SYMTAB_BLOCK_ID, bitc::SYMTAB_BLOB,
4830             {Symtab.data(), Symtab.size()});
4831 }
4832 
4833 void BitcodeWriter::writeStrtab() {
4834   assert(!WroteStrtab);
4835 
4836   std::vector<char> Strtab;
4837   StrtabBuilder.finalizeInOrder();
4838   Strtab.resize(StrtabBuilder.getSize());
4839   StrtabBuilder.write((uint8_t *)Strtab.data());
4840 
4841   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB,
4842             {Strtab.data(), Strtab.size()});
4843 
4844   WroteStrtab = true;
4845 }
4846 
4847 void BitcodeWriter::copyStrtab(StringRef Strtab) {
4848   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB, Strtab);
4849   WroteStrtab = true;
4850 }
4851 
4852 void BitcodeWriter::writeModule(const Module &M,
4853                                 bool ShouldPreserveUseListOrder,
4854                                 const ModuleSummaryIndex *Index,
4855                                 bool GenerateHash, ModuleHash *ModHash) {
4856   assert(!WroteStrtab);
4857 
4858   // The Mods vector is used by irsymtab::build, which requires non-const
4859   // Modules in case it needs to materialize metadata. But the bitcode writer
4860   // requires that the module is materialized, so we can cast to non-const here,
4861   // after checking that it is in fact materialized.
4862   assert(M.isMaterialized());
4863   Mods.push_back(const_cast<Module *>(&M));
4864 
4865   ModuleBitcodeWriter ModuleWriter(M, Buffer, StrtabBuilder, *Stream,
4866                                    ShouldPreserveUseListOrder, Index,
4867                                    GenerateHash, ModHash);
4868   ModuleWriter.write();
4869 }
4870 
4871 void BitcodeWriter::writeIndex(
4872     const ModuleSummaryIndex *Index,
4873     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4874   IndexBitcodeWriter IndexWriter(*Stream, StrtabBuilder, *Index,
4875                                  ModuleToSummariesForIndex);
4876   IndexWriter.write();
4877 }
4878 
4879 /// Write the specified module to the specified output stream.
4880 void llvm::WriteBitcodeToFile(const Module &M, raw_ostream &Out,
4881                               bool ShouldPreserveUseListOrder,
4882                               const ModuleSummaryIndex *Index,
4883                               bool GenerateHash, ModuleHash *ModHash) {
4884   SmallVector<char, 0> Buffer;
4885   Buffer.reserve(256*1024);
4886 
4887   // If this is darwin or another generic macho target, reserve space for the
4888   // header.
4889   Triple TT(M.getTargetTriple());
4890   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4891     Buffer.insert(Buffer.begin(), BWH_HeaderSize, 0);
4892 
4893   BitcodeWriter Writer(Buffer, dyn_cast<raw_fd_stream>(&Out));
4894   Writer.writeModule(M, ShouldPreserveUseListOrder, Index, GenerateHash,
4895                      ModHash);
4896   Writer.writeSymtab();
4897   Writer.writeStrtab();
4898 
4899   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4900     emitDarwinBCHeaderAndTrailer(Buffer, TT);
4901 
4902   // Write the generated bitstream to "Out".
4903   if (!Buffer.empty())
4904     Out.write((char *)&Buffer.front(), Buffer.size());
4905 }
4906 
4907 void IndexBitcodeWriter::write() {
4908   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4909 
4910   writeModuleVersion();
4911 
4912   // Write the module paths in the combined index.
4913   writeModStrings();
4914 
4915   // Write the summary combined index records.
4916   writeCombinedGlobalValueSummary();
4917 
4918   Stream.ExitBlock();
4919 }
4920 
4921 // Write the specified module summary index to the given raw output stream,
4922 // where it will be written in a new bitcode block. This is used when
4923 // writing the combined index file for ThinLTO. When writing a subset of the
4924 // index for a distributed backend, provide a \p ModuleToSummariesForIndex map.
4925 void llvm::writeIndexToFile(
4926     const ModuleSummaryIndex &Index, raw_ostream &Out,
4927     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4928   SmallVector<char, 0> Buffer;
4929   Buffer.reserve(256 * 1024);
4930 
4931   BitcodeWriter Writer(Buffer);
4932   Writer.writeIndex(&Index, ModuleToSummariesForIndex);
4933   Writer.writeStrtab();
4934 
4935   Out.write((char *)&Buffer.front(), Buffer.size());
4936 }
4937 
4938 namespace {
4939 
4940 /// Class to manage the bitcode writing for a thin link bitcode file.
4941 class ThinLinkBitcodeWriter : public ModuleBitcodeWriterBase {
4942   /// ModHash is for use in ThinLTO incremental build, generated while writing
4943   /// the module bitcode file.
4944   const ModuleHash *ModHash;
4945 
4946 public:
4947   ThinLinkBitcodeWriter(const Module &M, StringTableBuilder &StrtabBuilder,
4948                         BitstreamWriter &Stream,
4949                         const ModuleSummaryIndex &Index,
4950                         const ModuleHash &ModHash)
4951       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
4952                                 /*ShouldPreserveUseListOrder=*/false, &Index),
4953         ModHash(&ModHash) {}
4954 
4955   void write();
4956 
4957 private:
4958   void writeSimplifiedModuleInfo();
4959 };
4960 
4961 } // end anonymous namespace
4962 
4963 // This function writes a simpilified module info for thin link bitcode file.
4964 // It only contains the source file name along with the name(the offset and
4965 // size in strtab) and linkage for global values. For the global value info
4966 // entry, in order to keep linkage at offset 5, there are three zeros used
4967 // as padding.
4968 void ThinLinkBitcodeWriter::writeSimplifiedModuleInfo() {
4969   SmallVector<unsigned, 64> Vals;
4970   // Emit the module's source file name.
4971   {
4972     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
4973     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
4974     if (Bits == SE_Char6)
4975       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
4976     else if (Bits == SE_Fixed7)
4977       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
4978 
4979     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
4980     auto Abbv = std::make_shared<BitCodeAbbrev>();
4981     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
4982     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4983     Abbv->Add(AbbrevOpToUse);
4984     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4985 
4986     for (const auto P : M.getSourceFileName())
4987       Vals.push_back((unsigned char)P);
4988 
4989     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
4990     Vals.clear();
4991   }
4992 
4993   // Emit the global variable information.
4994   for (const GlobalVariable &GV : M.globals()) {
4995     // GLOBALVAR: [strtab offset, strtab size, 0, 0, 0, linkage]
4996     Vals.push_back(StrtabBuilder.add(GV.getName()));
4997     Vals.push_back(GV.getName().size());
4998     Vals.push_back(0);
4999     Vals.push_back(0);
5000     Vals.push_back(0);
5001     Vals.push_back(getEncodedLinkage(GV));
5002 
5003     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals);
5004     Vals.clear();
5005   }
5006 
5007   // Emit the function proto information.
5008   for (const Function &F : M) {
5009     // FUNCTION:  [strtab offset, strtab size, 0, 0, 0, linkage]
5010     Vals.push_back(StrtabBuilder.add(F.getName()));
5011     Vals.push_back(F.getName().size());
5012     Vals.push_back(0);
5013     Vals.push_back(0);
5014     Vals.push_back(0);
5015     Vals.push_back(getEncodedLinkage(F));
5016 
5017     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals);
5018     Vals.clear();
5019   }
5020 
5021   // Emit the alias information.
5022   for (const GlobalAlias &A : M.aliases()) {
5023     // ALIAS: [strtab offset, strtab size, 0, 0, 0, linkage]
5024     Vals.push_back(StrtabBuilder.add(A.getName()));
5025     Vals.push_back(A.getName().size());
5026     Vals.push_back(0);
5027     Vals.push_back(0);
5028     Vals.push_back(0);
5029     Vals.push_back(getEncodedLinkage(A));
5030 
5031     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals);
5032     Vals.clear();
5033   }
5034 
5035   // Emit the ifunc information.
5036   for (const GlobalIFunc &I : M.ifuncs()) {
5037     // IFUNC: [strtab offset, strtab size, 0, 0, 0, linkage]
5038     Vals.push_back(StrtabBuilder.add(I.getName()));
5039     Vals.push_back(I.getName().size());
5040     Vals.push_back(0);
5041     Vals.push_back(0);
5042     Vals.push_back(0);
5043     Vals.push_back(getEncodedLinkage(I));
5044 
5045     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
5046     Vals.clear();
5047   }
5048 }
5049 
5050 void ThinLinkBitcodeWriter::write() {
5051   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
5052 
5053   writeModuleVersion();
5054 
5055   writeSimplifiedModuleInfo();
5056 
5057   writePerModuleGlobalValueSummary();
5058 
5059   // Write module hash.
5060   Stream.EmitRecord(bitc::MODULE_CODE_HASH, ArrayRef<uint32_t>(*ModHash));
5061 
5062   Stream.ExitBlock();
5063 }
5064 
5065 void BitcodeWriter::writeThinLinkBitcode(const Module &M,
5066                                          const ModuleSummaryIndex &Index,
5067                                          const ModuleHash &ModHash) {
5068   assert(!WroteStrtab);
5069 
5070   // The Mods vector is used by irsymtab::build, which requires non-const
5071   // Modules in case it needs to materialize metadata. But the bitcode writer
5072   // requires that the module is materialized, so we can cast to non-const here,
5073   // after checking that it is in fact materialized.
5074   assert(M.isMaterialized());
5075   Mods.push_back(const_cast<Module *>(&M));
5076 
5077   ThinLinkBitcodeWriter ThinLinkWriter(M, StrtabBuilder, *Stream, Index,
5078                                        ModHash);
5079   ThinLinkWriter.write();
5080 }
5081 
5082 // Write the specified thin link bitcode file to the given raw output stream,
5083 // where it will be written in a new bitcode block. This is used when
5084 // writing the per-module index file for ThinLTO.
5085 void llvm::writeThinLinkBitcodeToFile(const Module &M, raw_ostream &Out,
5086                                       const ModuleSummaryIndex &Index,
5087                                       const ModuleHash &ModHash) {
5088   SmallVector<char, 0> Buffer;
5089   Buffer.reserve(256 * 1024);
5090 
5091   BitcodeWriter Writer(Buffer);
5092   Writer.writeThinLinkBitcode(M, Index, ModHash);
5093   Writer.writeSymtab();
5094   Writer.writeStrtab();
5095 
5096   Out.write((char *)&Buffer.front(), Buffer.size());
5097 }
5098 
5099 static const char *getSectionNameForBitcode(const Triple &T) {
5100   switch (T.getObjectFormat()) {
5101   case Triple::MachO:
5102     return "__LLVM,__bitcode";
5103   case Triple::COFF:
5104   case Triple::ELF:
5105   case Triple::Wasm:
5106   case Triple::UnknownObjectFormat:
5107     return ".llvmbc";
5108   case Triple::GOFF:
5109     llvm_unreachable("GOFF is not yet implemented");
5110     break;
5111   case Triple::SPIRV:
5112     llvm_unreachable("SPIRV is not yet implemented");
5113     break;
5114   case Triple::XCOFF:
5115     llvm_unreachable("XCOFF is not yet implemented");
5116     break;
5117   case Triple::DXContainer:
5118     llvm_unreachable("DXContainer is not yet implemented");
5119     break;
5120   }
5121   llvm_unreachable("Unimplemented ObjectFormatType");
5122 }
5123 
5124 static const char *getSectionNameForCommandline(const Triple &T) {
5125   switch (T.getObjectFormat()) {
5126   case Triple::MachO:
5127     return "__LLVM,__cmdline";
5128   case Triple::COFF:
5129   case Triple::ELF:
5130   case Triple::Wasm:
5131   case Triple::UnknownObjectFormat:
5132     return ".llvmcmd";
5133   case Triple::GOFF:
5134     llvm_unreachable("GOFF is not yet implemented");
5135     break;
5136   case Triple::SPIRV:
5137     llvm_unreachable("SPIRV is not yet implemented");
5138     break;
5139   case Triple::XCOFF:
5140     llvm_unreachable("XCOFF is not yet implemented");
5141     break;
5142   case Triple::DXContainer:
5143     llvm_unreachable("DXC is not yet implemented");
5144     break;
5145   }
5146   llvm_unreachable("Unimplemented ObjectFormatType");
5147 }
5148 
5149 void llvm::embedBitcodeInModule(llvm::Module &M, llvm::MemoryBufferRef Buf,
5150                                 bool EmbedBitcode, bool EmbedCmdline,
5151                                 const std::vector<uint8_t> &CmdArgs) {
5152   // Save llvm.compiler.used and remove it.
5153   SmallVector<Constant *, 2> UsedArray;
5154   SmallVector<GlobalValue *, 4> UsedGlobals;
5155   Type *UsedElementType = Type::getInt8Ty(M.getContext())->getPointerTo(0);
5156   GlobalVariable *Used = collectUsedGlobalVariables(M, UsedGlobals, true);
5157   for (auto *GV : UsedGlobals) {
5158     if (GV->getName() != "llvm.embedded.module" &&
5159         GV->getName() != "llvm.cmdline")
5160       UsedArray.push_back(
5161           ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
5162   }
5163   if (Used)
5164     Used->eraseFromParent();
5165 
5166   // Embed the bitcode for the llvm module.
5167   std::string Data;
5168   ArrayRef<uint8_t> ModuleData;
5169   Triple T(M.getTargetTriple());
5170 
5171   if (EmbedBitcode) {
5172     if (Buf.getBufferSize() == 0 ||
5173         !isBitcode((const unsigned char *)Buf.getBufferStart(),
5174                    (const unsigned char *)Buf.getBufferEnd())) {
5175       // If the input is LLVM Assembly, bitcode is produced by serializing
5176       // the module. Use-lists order need to be preserved in this case.
5177       llvm::raw_string_ostream OS(Data);
5178       llvm::WriteBitcodeToFile(M, OS, /* ShouldPreserveUseListOrder */ true);
5179       ModuleData =
5180           ArrayRef<uint8_t>((const uint8_t *)OS.str().data(), OS.str().size());
5181     } else
5182       // If the input is LLVM bitcode, write the input byte stream directly.
5183       ModuleData = ArrayRef<uint8_t>((const uint8_t *)Buf.getBufferStart(),
5184                                      Buf.getBufferSize());
5185   }
5186   llvm::Constant *ModuleConstant =
5187       llvm::ConstantDataArray::get(M.getContext(), ModuleData);
5188   llvm::GlobalVariable *GV = new llvm::GlobalVariable(
5189       M, ModuleConstant->getType(), true, llvm::GlobalValue::PrivateLinkage,
5190       ModuleConstant);
5191   GV->setSection(getSectionNameForBitcode(T));
5192   // Set alignment to 1 to prevent padding between two contributions from input
5193   // sections after linking.
5194   GV->setAlignment(Align(1));
5195   UsedArray.push_back(
5196       ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
5197   if (llvm::GlobalVariable *Old =
5198           M.getGlobalVariable("llvm.embedded.module", true)) {
5199     assert(Old->hasZeroLiveUses() &&
5200            "llvm.embedded.module can only be used once in llvm.compiler.used");
5201     GV->takeName(Old);
5202     Old->eraseFromParent();
5203   } else {
5204     GV->setName("llvm.embedded.module");
5205   }
5206 
5207   // Skip if only bitcode needs to be embedded.
5208   if (EmbedCmdline) {
5209     // Embed command-line options.
5210     ArrayRef<uint8_t> CmdData(const_cast<uint8_t *>(CmdArgs.data()),
5211                               CmdArgs.size());
5212     llvm::Constant *CmdConstant =
5213         llvm::ConstantDataArray::get(M.getContext(), CmdData);
5214     GV = new llvm::GlobalVariable(M, CmdConstant->getType(), true,
5215                                   llvm::GlobalValue::PrivateLinkage,
5216                                   CmdConstant);
5217     GV->setSection(getSectionNameForCommandline(T));
5218     GV->setAlignment(Align(1));
5219     UsedArray.push_back(
5220         ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
5221     if (llvm::GlobalVariable *Old = M.getGlobalVariable("llvm.cmdline", true)) {
5222       assert(Old->hasZeroLiveUses() &&
5223              "llvm.cmdline can only be used once in llvm.compiler.used");
5224       GV->takeName(Old);
5225       Old->eraseFromParent();
5226     } else {
5227       GV->setName("llvm.cmdline");
5228     }
5229   }
5230 
5231   if (UsedArray.empty())
5232     return;
5233 
5234   // Recreate llvm.compiler.used.
5235   ArrayType *ATy = ArrayType::get(UsedElementType, UsedArray.size());
5236   auto *NewUsed = new GlobalVariable(
5237       M, ATy, false, llvm::GlobalValue::AppendingLinkage,
5238       llvm::ConstantArray::get(ATy, UsedArray), "llvm.compiler.used");
5239   NewUsed->setSection("llvm.metadata");
5240 }
5241