xref: /llvm-project/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp (revision df3478e480b3b2e9fe125697b7931dc48b09e450)
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::OptimizeForDebugging:
751     return bitc::ATTR_KIND_OPTIMIZE_FOR_DEBUGGING;
752   case Attribute::OptForFuzzing:
753     return bitc::ATTR_KIND_OPT_FOR_FUZZING;
754   case Attribute::OptimizeForSize:
755     return bitc::ATTR_KIND_OPTIMIZE_FOR_SIZE;
756   case Attribute::OptimizeNone:
757     return bitc::ATTR_KIND_OPTIMIZE_NONE;
758   case Attribute::ReadNone:
759     return bitc::ATTR_KIND_READ_NONE;
760   case Attribute::ReadOnly:
761     return bitc::ATTR_KIND_READ_ONLY;
762   case Attribute::Returned:
763     return bitc::ATTR_KIND_RETURNED;
764   case Attribute::ReturnsTwice:
765     return bitc::ATTR_KIND_RETURNS_TWICE;
766   case Attribute::SExt:
767     return bitc::ATTR_KIND_S_EXT;
768   case Attribute::Speculatable:
769     return bitc::ATTR_KIND_SPECULATABLE;
770   case Attribute::StackAlignment:
771     return bitc::ATTR_KIND_STACK_ALIGNMENT;
772   case Attribute::StackProtect:
773     return bitc::ATTR_KIND_STACK_PROTECT;
774   case Attribute::StackProtectReq:
775     return bitc::ATTR_KIND_STACK_PROTECT_REQ;
776   case Attribute::StackProtectStrong:
777     return bitc::ATTR_KIND_STACK_PROTECT_STRONG;
778   case Attribute::SafeStack:
779     return bitc::ATTR_KIND_SAFESTACK;
780   case Attribute::ShadowCallStack:
781     return bitc::ATTR_KIND_SHADOWCALLSTACK;
782   case Attribute::StrictFP:
783     return bitc::ATTR_KIND_STRICT_FP;
784   case Attribute::StructRet:
785     return bitc::ATTR_KIND_STRUCT_RET;
786   case Attribute::SanitizeAddress:
787     return bitc::ATTR_KIND_SANITIZE_ADDRESS;
788   case Attribute::SanitizeHWAddress:
789     return bitc::ATTR_KIND_SANITIZE_HWADDRESS;
790   case Attribute::SanitizeThread:
791     return bitc::ATTR_KIND_SANITIZE_THREAD;
792   case Attribute::SanitizeMemory:
793     return bitc::ATTR_KIND_SANITIZE_MEMORY;
794   case Attribute::SpeculativeLoadHardening:
795     return bitc::ATTR_KIND_SPECULATIVE_LOAD_HARDENING;
796   case Attribute::SwiftError:
797     return bitc::ATTR_KIND_SWIFT_ERROR;
798   case Attribute::SwiftSelf:
799     return bitc::ATTR_KIND_SWIFT_SELF;
800   case Attribute::SwiftAsync:
801     return bitc::ATTR_KIND_SWIFT_ASYNC;
802   case Attribute::UWTable:
803     return bitc::ATTR_KIND_UW_TABLE;
804   case Attribute::VScaleRange:
805     return bitc::ATTR_KIND_VSCALE_RANGE;
806   case Attribute::WillReturn:
807     return bitc::ATTR_KIND_WILLRETURN;
808   case Attribute::WriteOnly:
809     return bitc::ATTR_KIND_WRITEONLY;
810   case Attribute::ZExt:
811     return bitc::ATTR_KIND_Z_EXT;
812   case Attribute::ImmArg:
813     return bitc::ATTR_KIND_IMMARG;
814   case Attribute::SanitizeMemTag:
815     return bitc::ATTR_KIND_SANITIZE_MEMTAG;
816   case Attribute::Preallocated:
817     return bitc::ATTR_KIND_PREALLOCATED;
818   case Attribute::NoUndef:
819     return bitc::ATTR_KIND_NOUNDEF;
820   case Attribute::ByRef:
821     return bitc::ATTR_KIND_BYREF;
822   case Attribute::MustProgress:
823     return bitc::ATTR_KIND_MUSTPROGRESS;
824   case Attribute::PresplitCoroutine:
825     return bitc::ATTR_KIND_PRESPLIT_COROUTINE;
826   case Attribute::EndAttrKinds:
827     llvm_unreachable("Can not encode end-attribute kinds marker.");
828   case Attribute::None:
829     llvm_unreachable("Can not encode none-attribute.");
830   case Attribute::EmptyKey:
831   case Attribute::TombstoneKey:
832     llvm_unreachable("Trying to encode EmptyKey/TombstoneKey");
833   }
834 
835   llvm_unreachable("Trying to encode unknown attribute");
836 }
837 
838 void ModuleBitcodeWriter::writeAttributeGroupTable() {
839   const std::vector<ValueEnumerator::IndexAndAttrSet> &AttrGrps =
840       VE.getAttributeGroups();
841   if (AttrGrps.empty()) return;
842 
843   Stream.EnterSubblock(bitc::PARAMATTR_GROUP_BLOCK_ID, 3);
844 
845   SmallVector<uint64_t, 64> Record;
846   for (ValueEnumerator::IndexAndAttrSet Pair : AttrGrps) {
847     unsigned AttrListIndex = Pair.first;
848     AttributeSet AS = Pair.second;
849     Record.push_back(VE.getAttributeGroupID(Pair));
850     Record.push_back(AttrListIndex);
851 
852     for (Attribute Attr : AS) {
853       if (Attr.isEnumAttribute()) {
854         Record.push_back(0);
855         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
856       } else if (Attr.isIntAttribute()) {
857         Record.push_back(1);
858         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
859         Record.push_back(Attr.getValueAsInt());
860       } else if (Attr.isStringAttribute()) {
861         StringRef Kind = Attr.getKindAsString();
862         StringRef Val = Attr.getValueAsString();
863 
864         Record.push_back(Val.empty() ? 3 : 4);
865         Record.append(Kind.begin(), Kind.end());
866         Record.push_back(0);
867         if (!Val.empty()) {
868           Record.append(Val.begin(), Val.end());
869           Record.push_back(0);
870         }
871       } else {
872         assert(Attr.isTypeAttribute());
873         Type *Ty = Attr.getValueAsType();
874         Record.push_back(Ty ? 6 : 5);
875         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
876         if (Ty)
877           Record.push_back(VE.getTypeID(Attr.getValueAsType()));
878       }
879     }
880 
881     Stream.EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
882     Record.clear();
883   }
884 
885   Stream.ExitBlock();
886 }
887 
888 void ModuleBitcodeWriter::writeAttributeTable() {
889   const std::vector<AttributeList> &Attrs = VE.getAttributeLists();
890   if (Attrs.empty()) return;
891 
892   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
893 
894   SmallVector<uint64_t, 64> Record;
895   for (const AttributeList &AL : Attrs) {
896     for (unsigned i : AL.indexes()) {
897       AttributeSet AS = AL.getAttributes(i);
898       if (AS.hasAttributes())
899         Record.push_back(VE.getAttributeGroupID({i, AS}));
900     }
901 
902     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
903     Record.clear();
904   }
905 
906   Stream.ExitBlock();
907 }
908 
909 /// WriteTypeTable - Write out the type table for a module.
910 void ModuleBitcodeWriter::writeTypeTable() {
911   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
912 
913   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
914   SmallVector<uint64_t, 64> TypeVals;
915 
916   uint64_t NumBits = VE.computeBitsRequiredForTypeIndicies();
917 
918   // Abbrev for TYPE_CODE_OPAQUE_POINTER.
919   auto Abbv = std::make_shared<BitCodeAbbrev>();
920   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_OPAQUE_POINTER));
921   Abbv->Add(BitCodeAbbrevOp(0)); // Addrspace = 0
922   unsigned OpaquePtrAbbrev = Stream.EmitAbbrev(std::move(Abbv));
923 
924   // Abbrev for TYPE_CODE_FUNCTION.
925   Abbv = std::make_shared<BitCodeAbbrev>();
926   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
927   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
928   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
929   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
930   unsigned FunctionAbbrev = Stream.EmitAbbrev(std::move(Abbv));
931 
932   // Abbrev for TYPE_CODE_STRUCT_ANON.
933   Abbv = std::make_shared<BitCodeAbbrev>();
934   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
935   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
936   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
937   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
938   unsigned StructAnonAbbrev = Stream.EmitAbbrev(std::move(Abbv));
939 
940   // Abbrev for TYPE_CODE_STRUCT_NAME.
941   Abbv = std::make_shared<BitCodeAbbrev>();
942   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
943   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
944   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
945   unsigned StructNameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
946 
947   // Abbrev for TYPE_CODE_STRUCT_NAMED.
948   Abbv = std::make_shared<BitCodeAbbrev>();
949   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
950   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
951   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
952   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
953   unsigned StructNamedAbbrev = Stream.EmitAbbrev(std::move(Abbv));
954 
955   // Abbrev for TYPE_CODE_ARRAY.
956   Abbv = std::make_shared<BitCodeAbbrev>();
957   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
958   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
959   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
960   unsigned ArrayAbbrev = Stream.EmitAbbrev(std::move(Abbv));
961 
962   // Emit an entry count so the reader can reserve space.
963   TypeVals.push_back(TypeList.size());
964   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
965   TypeVals.clear();
966 
967   // Loop over all of the types, emitting each in turn.
968   for (Type *T : TypeList) {
969     int AbbrevToUse = 0;
970     unsigned Code = 0;
971 
972     switch (T->getTypeID()) {
973     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;      break;
974     case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;      break;
975     case Type::BFloatTyID:    Code = bitc::TYPE_CODE_BFLOAT;    break;
976     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;     break;
977     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE;    break;
978     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80;  break;
979     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128;     break;
980     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
981     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;     break;
982     case Type::MetadataTyID:  Code = bitc::TYPE_CODE_METADATA;  break;
983     case Type::X86_MMXTyID:   Code = bitc::TYPE_CODE_X86_MMX;   break;
984     case Type::X86_AMXTyID:   Code = bitc::TYPE_CODE_X86_AMX;   break;
985     case Type::TokenTyID:     Code = bitc::TYPE_CODE_TOKEN;     break;
986     case Type::IntegerTyID:
987       // INTEGER: [width]
988       Code = bitc::TYPE_CODE_INTEGER;
989       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
990       break;
991     case Type::PointerTyID: {
992       PointerType *PTy = cast<PointerType>(T);
993       unsigned AddressSpace = PTy->getAddressSpace();
994       // OPAQUE_POINTER: [address space]
995       Code = bitc::TYPE_CODE_OPAQUE_POINTER;
996       TypeVals.push_back(AddressSpace);
997       if (AddressSpace == 0)
998         AbbrevToUse = OpaquePtrAbbrev;
999       break;
1000     }
1001     case Type::FunctionTyID: {
1002       FunctionType *FT = cast<FunctionType>(T);
1003       // FUNCTION: [isvararg, retty, paramty x N]
1004       Code = bitc::TYPE_CODE_FUNCTION;
1005       TypeVals.push_back(FT->isVarArg());
1006       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
1007       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
1008         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
1009       AbbrevToUse = FunctionAbbrev;
1010       break;
1011     }
1012     case Type::StructTyID: {
1013       StructType *ST = cast<StructType>(T);
1014       // STRUCT: [ispacked, eltty x N]
1015       TypeVals.push_back(ST->isPacked());
1016       // Output all of the element types.
1017       for (Type *ET : ST->elements())
1018         TypeVals.push_back(VE.getTypeID(ET));
1019 
1020       if (ST->isLiteral()) {
1021         Code = bitc::TYPE_CODE_STRUCT_ANON;
1022         AbbrevToUse = StructAnonAbbrev;
1023       } else {
1024         if (ST->isOpaque()) {
1025           Code = bitc::TYPE_CODE_OPAQUE;
1026         } else {
1027           Code = bitc::TYPE_CODE_STRUCT_NAMED;
1028           AbbrevToUse = StructNamedAbbrev;
1029         }
1030 
1031         // Emit the name if it is present.
1032         if (!ST->getName().empty())
1033           writeStringRecord(Stream, bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
1034                             StructNameAbbrev);
1035       }
1036       break;
1037     }
1038     case Type::ArrayTyID: {
1039       ArrayType *AT = cast<ArrayType>(T);
1040       // ARRAY: [numelts, eltty]
1041       Code = bitc::TYPE_CODE_ARRAY;
1042       TypeVals.push_back(AT->getNumElements());
1043       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
1044       AbbrevToUse = ArrayAbbrev;
1045       break;
1046     }
1047     case Type::FixedVectorTyID:
1048     case Type::ScalableVectorTyID: {
1049       VectorType *VT = cast<VectorType>(T);
1050       // VECTOR [numelts, eltty] or
1051       //        [numelts, eltty, scalable]
1052       Code = bitc::TYPE_CODE_VECTOR;
1053       TypeVals.push_back(VT->getElementCount().getKnownMinValue());
1054       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
1055       if (isa<ScalableVectorType>(VT))
1056         TypeVals.push_back(true);
1057       break;
1058     }
1059     case Type::TargetExtTyID: {
1060       TargetExtType *TET = cast<TargetExtType>(T);
1061       Code = bitc::TYPE_CODE_TARGET_TYPE;
1062       writeStringRecord(Stream, bitc::TYPE_CODE_STRUCT_NAME, TET->getName(),
1063                         StructNameAbbrev);
1064       TypeVals.push_back(TET->getNumTypeParameters());
1065       for (Type *InnerTy : TET->type_params())
1066         TypeVals.push_back(VE.getTypeID(InnerTy));
1067       for (unsigned IntParam : TET->int_params())
1068         TypeVals.push_back(IntParam);
1069       break;
1070     }
1071     case Type::TypedPointerTyID:
1072       llvm_unreachable("Typed pointers cannot be added to IR modules");
1073     }
1074 
1075     // Emit the finished record.
1076     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
1077     TypeVals.clear();
1078   }
1079 
1080   Stream.ExitBlock();
1081 }
1082 
1083 static unsigned getEncodedLinkage(const GlobalValue::LinkageTypes Linkage) {
1084   switch (Linkage) {
1085   case GlobalValue::ExternalLinkage:
1086     return 0;
1087   case GlobalValue::WeakAnyLinkage:
1088     return 16;
1089   case GlobalValue::AppendingLinkage:
1090     return 2;
1091   case GlobalValue::InternalLinkage:
1092     return 3;
1093   case GlobalValue::LinkOnceAnyLinkage:
1094     return 18;
1095   case GlobalValue::ExternalWeakLinkage:
1096     return 7;
1097   case GlobalValue::CommonLinkage:
1098     return 8;
1099   case GlobalValue::PrivateLinkage:
1100     return 9;
1101   case GlobalValue::WeakODRLinkage:
1102     return 17;
1103   case GlobalValue::LinkOnceODRLinkage:
1104     return 19;
1105   case GlobalValue::AvailableExternallyLinkage:
1106     return 12;
1107   }
1108   llvm_unreachable("Invalid linkage");
1109 }
1110 
1111 static unsigned getEncodedLinkage(const GlobalValue &GV) {
1112   return getEncodedLinkage(GV.getLinkage());
1113 }
1114 
1115 static uint64_t getEncodedFFlags(FunctionSummary::FFlags Flags) {
1116   uint64_t RawFlags = 0;
1117   RawFlags |= Flags.ReadNone;
1118   RawFlags |= (Flags.ReadOnly << 1);
1119   RawFlags |= (Flags.NoRecurse << 2);
1120   RawFlags |= (Flags.ReturnDoesNotAlias << 3);
1121   RawFlags |= (Flags.NoInline << 4);
1122   RawFlags |= (Flags.AlwaysInline << 5);
1123   RawFlags |= (Flags.NoUnwind << 6);
1124   RawFlags |= (Flags.MayThrow << 7);
1125   RawFlags |= (Flags.HasUnknownCall << 8);
1126   RawFlags |= (Flags.MustBeUnreachable << 9);
1127   return RawFlags;
1128 }
1129 
1130 // Decode the flags for GlobalValue in the summary. See getDecodedGVSummaryFlags
1131 // in BitcodeReader.cpp.
1132 static uint64_t getEncodedGVSummaryFlags(GlobalValueSummary::GVFlags Flags) {
1133   uint64_t RawFlags = 0;
1134 
1135   RawFlags |= Flags.NotEligibleToImport; // bool
1136   RawFlags |= (Flags.Live << 1);
1137   RawFlags |= (Flags.DSOLocal << 2);
1138   RawFlags |= (Flags.CanAutoHide << 3);
1139 
1140   // Linkage don't need to be remapped at that time for the summary. Any future
1141   // change to the getEncodedLinkage() function will need to be taken into
1142   // account here as well.
1143   RawFlags = (RawFlags << 4) | Flags.Linkage; // 4 bits
1144 
1145   RawFlags |= (Flags.Visibility << 8); // 2 bits
1146 
1147   return RawFlags;
1148 }
1149 
1150 static uint64_t getEncodedGVarFlags(GlobalVarSummary::GVarFlags Flags) {
1151   uint64_t RawFlags = Flags.MaybeReadOnly | (Flags.MaybeWriteOnly << 1) |
1152                       (Flags.Constant << 2) | Flags.VCallVisibility << 3;
1153   return RawFlags;
1154 }
1155 
1156 static unsigned getEncodedVisibility(const GlobalValue &GV) {
1157   switch (GV.getVisibility()) {
1158   case GlobalValue::DefaultVisibility:   return 0;
1159   case GlobalValue::HiddenVisibility:    return 1;
1160   case GlobalValue::ProtectedVisibility: return 2;
1161   }
1162   llvm_unreachable("Invalid visibility");
1163 }
1164 
1165 static unsigned getEncodedDLLStorageClass(const GlobalValue &GV) {
1166   switch (GV.getDLLStorageClass()) {
1167   case GlobalValue::DefaultStorageClass:   return 0;
1168   case GlobalValue::DLLImportStorageClass: return 1;
1169   case GlobalValue::DLLExportStorageClass: return 2;
1170   }
1171   llvm_unreachable("Invalid DLL storage class");
1172 }
1173 
1174 static unsigned getEncodedThreadLocalMode(const GlobalValue &GV) {
1175   switch (GV.getThreadLocalMode()) {
1176     case GlobalVariable::NotThreadLocal:         return 0;
1177     case GlobalVariable::GeneralDynamicTLSModel: return 1;
1178     case GlobalVariable::LocalDynamicTLSModel:   return 2;
1179     case GlobalVariable::InitialExecTLSModel:    return 3;
1180     case GlobalVariable::LocalExecTLSModel:      return 4;
1181   }
1182   llvm_unreachable("Invalid TLS model");
1183 }
1184 
1185 static unsigned getEncodedComdatSelectionKind(const Comdat &C) {
1186   switch (C.getSelectionKind()) {
1187   case Comdat::Any:
1188     return bitc::COMDAT_SELECTION_KIND_ANY;
1189   case Comdat::ExactMatch:
1190     return bitc::COMDAT_SELECTION_KIND_EXACT_MATCH;
1191   case Comdat::Largest:
1192     return bitc::COMDAT_SELECTION_KIND_LARGEST;
1193   case Comdat::NoDeduplicate:
1194     return bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES;
1195   case Comdat::SameSize:
1196     return bitc::COMDAT_SELECTION_KIND_SAME_SIZE;
1197   }
1198   llvm_unreachable("Invalid selection kind");
1199 }
1200 
1201 static unsigned getEncodedUnnamedAddr(const GlobalValue &GV) {
1202   switch (GV.getUnnamedAddr()) {
1203   case GlobalValue::UnnamedAddr::None:   return 0;
1204   case GlobalValue::UnnamedAddr::Local:  return 2;
1205   case GlobalValue::UnnamedAddr::Global: return 1;
1206   }
1207   llvm_unreachable("Invalid unnamed_addr");
1208 }
1209 
1210 size_t ModuleBitcodeWriter::addToStrtab(StringRef Str) {
1211   if (GenerateHash)
1212     Hasher.update(Str);
1213   return StrtabBuilder.add(Str);
1214 }
1215 
1216 void ModuleBitcodeWriter::writeComdats() {
1217   SmallVector<unsigned, 64> Vals;
1218   for (const Comdat *C : VE.getComdats()) {
1219     // COMDAT: [strtab offset, strtab size, selection_kind]
1220     Vals.push_back(addToStrtab(C->getName()));
1221     Vals.push_back(C->getName().size());
1222     Vals.push_back(getEncodedComdatSelectionKind(*C));
1223     Stream.EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
1224     Vals.clear();
1225   }
1226 }
1227 
1228 /// Write a record that will eventually hold the word offset of the
1229 /// module-level VST. For now the offset is 0, which will be backpatched
1230 /// after the real VST is written. Saves the bit offset to backpatch.
1231 void ModuleBitcodeWriter::writeValueSymbolTableForwardDecl() {
1232   // Write a placeholder value in for the offset of the real VST,
1233   // which is written after the function blocks so that it can include
1234   // the offset of each function. The placeholder offset will be
1235   // updated when the real VST is written.
1236   auto Abbv = std::make_shared<BitCodeAbbrev>();
1237   Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_VSTOFFSET));
1238   // Blocks are 32-bit aligned, so we can use a 32-bit word offset to
1239   // hold the real VST offset. Must use fixed instead of VBR as we don't
1240   // know how many VBR chunks to reserve ahead of time.
1241   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
1242   unsigned VSTOffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1243 
1244   // Emit the placeholder
1245   uint64_t Vals[] = {bitc::MODULE_CODE_VSTOFFSET, 0};
1246   Stream.EmitRecordWithAbbrev(VSTOffsetAbbrev, Vals);
1247 
1248   // Compute and save the bit offset to the placeholder, which will be
1249   // patched when the real VST is written. We can simply subtract the 32-bit
1250   // fixed size from the current bit number to get the location to backpatch.
1251   VSTOffsetPlaceholder = Stream.GetCurrentBitNo() - 32;
1252 }
1253 
1254 enum StringEncoding { SE_Char6, SE_Fixed7, SE_Fixed8 };
1255 
1256 /// Determine the encoding to use for the given string name and length.
1257 static StringEncoding getStringEncoding(StringRef Str) {
1258   bool isChar6 = true;
1259   for (char C : Str) {
1260     if (isChar6)
1261       isChar6 = BitCodeAbbrevOp::isChar6(C);
1262     if ((unsigned char)C & 128)
1263       // don't bother scanning the rest.
1264       return SE_Fixed8;
1265   }
1266   if (isChar6)
1267     return SE_Char6;
1268   return SE_Fixed7;
1269 }
1270 
1271 static_assert(sizeof(GlobalValue::SanitizerMetadata) <= sizeof(unsigned),
1272               "Sanitizer Metadata is too large for naive serialization.");
1273 static unsigned
1274 serializeSanitizerMetadata(const GlobalValue::SanitizerMetadata &Meta) {
1275   return Meta.NoAddress | (Meta.NoHWAddress << 1) |
1276          (Meta.Memtag << 2) | (Meta.IsDynInit << 3);
1277 }
1278 
1279 /// Emit top-level description of module, including target triple, inline asm,
1280 /// descriptors for global variables, and function prototype info.
1281 /// Returns the bit offset to backpatch with the location of the real VST.
1282 void ModuleBitcodeWriter::writeModuleInfo() {
1283   // Emit various pieces of data attached to a module.
1284   if (!M.getTargetTriple().empty())
1285     writeStringRecord(Stream, bitc::MODULE_CODE_TRIPLE, M.getTargetTriple(),
1286                       0 /*TODO*/);
1287   const std::string &DL = M.getDataLayoutStr();
1288   if (!DL.empty())
1289     writeStringRecord(Stream, bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/);
1290   if (!M.getModuleInlineAsm().empty())
1291     writeStringRecord(Stream, bitc::MODULE_CODE_ASM, M.getModuleInlineAsm(),
1292                       0 /*TODO*/);
1293 
1294   // Emit information about sections and GC, computing how many there are. Also
1295   // compute the maximum alignment value.
1296   std::map<std::string, unsigned> SectionMap;
1297   std::map<std::string, unsigned> GCMap;
1298   MaybeAlign MaxAlignment;
1299   unsigned MaxGlobalType = 0;
1300   const auto UpdateMaxAlignment = [&MaxAlignment](const MaybeAlign A) {
1301     if (A)
1302       MaxAlignment = !MaxAlignment ? *A : std::max(*MaxAlignment, *A);
1303   };
1304   for (const GlobalVariable &GV : M.globals()) {
1305     UpdateMaxAlignment(GV.getAlign());
1306     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getValueType()));
1307     if (GV.hasSection()) {
1308       // Give section names unique ID's.
1309       unsigned &Entry = SectionMap[std::string(GV.getSection())];
1310       if (!Entry) {
1311         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
1312                           0 /*TODO*/);
1313         Entry = SectionMap.size();
1314       }
1315     }
1316   }
1317   for (const Function &F : M) {
1318     UpdateMaxAlignment(F.getAlign());
1319     if (F.hasSection()) {
1320       // Give section names unique ID's.
1321       unsigned &Entry = SectionMap[std::string(F.getSection())];
1322       if (!Entry) {
1323         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
1324                           0 /*TODO*/);
1325         Entry = SectionMap.size();
1326       }
1327     }
1328     if (F.hasGC()) {
1329       // Same for GC names.
1330       unsigned &Entry = GCMap[F.getGC()];
1331       if (!Entry) {
1332         writeStringRecord(Stream, bitc::MODULE_CODE_GCNAME, F.getGC(),
1333                           0 /*TODO*/);
1334         Entry = GCMap.size();
1335       }
1336     }
1337   }
1338 
1339   // Emit abbrev for globals, now that we know # sections and max alignment.
1340   unsigned SimpleGVarAbbrev = 0;
1341   if (!M.global_empty()) {
1342     // Add an abbrev for common globals with no visibility or thread localness.
1343     auto Abbv = std::make_shared<BitCodeAbbrev>();
1344     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
1345     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1346     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1347     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1348                               Log2_32_Ceil(MaxGlobalType+1)));
1349     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddrSpace << 2
1350                                                            //| explicitType << 1
1351                                                            //| constant
1352     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Initializer.
1353     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // Linkage.
1354     if (!MaxAlignment)                                     // Alignment.
1355       Abbv->Add(BitCodeAbbrevOp(0));
1356     else {
1357       unsigned MaxEncAlignment = getEncodedAlign(MaxAlignment);
1358       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1359                                Log2_32_Ceil(MaxEncAlignment+1)));
1360     }
1361     if (SectionMap.empty())                                    // Section.
1362       Abbv->Add(BitCodeAbbrevOp(0));
1363     else
1364       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1365                                Log2_32_Ceil(SectionMap.size()+1)));
1366     // Don't bother emitting vis + thread local.
1367     SimpleGVarAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1368   }
1369 
1370   SmallVector<unsigned, 64> Vals;
1371   // Emit the module's source file name.
1372   {
1373     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
1374     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
1375     if (Bits == SE_Char6)
1376       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
1377     else if (Bits == SE_Fixed7)
1378       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
1379 
1380     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
1381     auto Abbv = std::make_shared<BitCodeAbbrev>();
1382     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
1383     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1384     Abbv->Add(AbbrevOpToUse);
1385     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1386 
1387     for (const auto P : M.getSourceFileName())
1388       Vals.push_back((unsigned char)P);
1389 
1390     // Emit the finished record.
1391     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
1392     Vals.clear();
1393   }
1394 
1395   // Emit the global variable information.
1396   for (const GlobalVariable &GV : M.globals()) {
1397     unsigned AbbrevToUse = 0;
1398 
1399     // GLOBALVAR: [strtab offset, strtab size, type, isconst, initid,
1400     //             linkage, alignment, section, visibility, threadlocal,
1401     //             unnamed_addr, externally_initialized, dllstorageclass,
1402     //             comdat, attributes, DSO_Local, GlobalSanitizer]
1403     Vals.push_back(addToStrtab(GV.getName()));
1404     Vals.push_back(GV.getName().size());
1405     Vals.push_back(VE.getTypeID(GV.getValueType()));
1406     Vals.push_back(GV.getType()->getAddressSpace() << 2 | 2 | GV.isConstant());
1407     Vals.push_back(GV.isDeclaration() ? 0 :
1408                    (VE.getValueID(GV.getInitializer()) + 1));
1409     Vals.push_back(getEncodedLinkage(GV));
1410     Vals.push_back(getEncodedAlign(GV.getAlign()));
1411     Vals.push_back(GV.hasSection() ? SectionMap[std::string(GV.getSection())]
1412                                    : 0);
1413     if (GV.isThreadLocal() ||
1414         GV.getVisibility() != GlobalValue::DefaultVisibility ||
1415         GV.getUnnamedAddr() != GlobalValue::UnnamedAddr::None ||
1416         GV.isExternallyInitialized() ||
1417         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
1418         GV.hasComdat() || GV.hasAttributes() || GV.isDSOLocal() ||
1419         GV.hasPartition() || GV.hasSanitizerMetadata()) {
1420       Vals.push_back(getEncodedVisibility(GV));
1421       Vals.push_back(getEncodedThreadLocalMode(GV));
1422       Vals.push_back(getEncodedUnnamedAddr(GV));
1423       Vals.push_back(GV.isExternallyInitialized());
1424       Vals.push_back(getEncodedDLLStorageClass(GV));
1425       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
1426 
1427       auto AL = GV.getAttributesAsList(AttributeList::FunctionIndex);
1428       Vals.push_back(VE.getAttributeListID(AL));
1429 
1430       Vals.push_back(GV.isDSOLocal());
1431       Vals.push_back(addToStrtab(GV.getPartition()));
1432       Vals.push_back(GV.getPartition().size());
1433 
1434       Vals.push_back((GV.hasSanitizerMetadata() ? serializeSanitizerMetadata(
1435                                                       GV.getSanitizerMetadata())
1436                                                 : 0));
1437     } else {
1438       AbbrevToUse = SimpleGVarAbbrev;
1439     }
1440 
1441     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
1442     Vals.clear();
1443   }
1444 
1445   // Emit the function proto information.
1446   for (const Function &F : M) {
1447     // FUNCTION:  [strtab offset, strtab size, type, callingconv, isproto,
1448     //             linkage, paramattrs, alignment, section, visibility, gc,
1449     //             unnamed_addr, prologuedata, dllstorageclass, comdat,
1450     //             prefixdata, personalityfn, DSO_Local, addrspace]
1451     Vals.push_back(addToStrtab(F.getName()));
1452     Vals.push_back(F.getName().size());
1453     Vals.push_back(VE.getTypeID(F.getFunctionType()));
1454     Vals.push_back(F.getCallingConv());
1455     Vals.push_back(F.isDeclaration());
1456     Vals.push_back(getEncodedLinkage(F));
1457     Vals.push_back(VE.getAttributeListID(F.getAttributes()));
1458     Vals.push_back(getEncodedAlign(F.getAlign()));
1459     Vals.push_back(F.hasSection() ? SectionMap[std::string(F.getSection())]
1460                                   : 0);
1461     Vals.push_back(getEncodedVisibility(F));
1462     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
1463     Vals.push_back(getEncodedUnnamedAddr(F));
1464     Vals.push_back(F.hasPrologueData() ? (VE.getValueID(F.getPrologueData()) + 1)
1465                                        : 0);
1466     Vals.push_back(getEncodedDLLStorageClass(F));
1467     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
1468     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
1469                                      : 0);
1470     Vals.push_back(
1471         F.hasPersonalityFn() ? (VE.getValueID(F.getPersonalityFn()) + 1) : 0);
1472 
1473     Vals.push_back(F.isDSOLocal());
1474     Vals.push_back(F.getAddressSpace());
1475     Vals.push_back(addToStrtab(F.getPartition()));
1476     Vals.push_back(F.getPartition().size());
1477 
1478     unsigned AbbrevToUse = 0;
1479     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
1480     Vals.clear();
1481   }
1482 
1483   // Emit the alias information.
1484   for (const GlobalAlias &A : M.aliases()) {
1485     // ALIAS: [strtab offset, strtab size, alias type, aliasee val#, linkage,
1486     //         visibility, dllstorageclass, threadlocal, unnamed_addr,
1487     //         DSO_Local]
1488     Vals.push_back(addToStrtab(A.getName()));
1489     Vals.push_back(A.getName().size());
1490     Vals.push_back(VE.getTypeID(A.getValueType()));
1491     Vals.push_back(A.getType()->getAddressSpace());
1492     Vals.push_back(VE.getValueID(A.getAliasee()));
1493     Vals.push_back(getEncodedLinkage(A));
1494     Vals.push_back(getEncodedVisibility(A));
1495     Vals.push_back(getEncodedDLLStorageClass(A));
1496     Vals.push_back(getEncodedThreadLocalMode(A));
1497     Vals.push_back(getEncodedUnnamedAddr(A));
1498     Vals.push_back(A.isDSOLocal());
1499     Vals.push_back(addToStrtab(A.getPartition()));
1500     Vals.push_back(A.getPartition().size());
1501 
1502     unsigned AbbrevToUse = 0;
1503     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
1504     Vals.clear();
1505   }
1506 
1507   // Emit the ifunc information.
1508   for (const GlobalIFunc &I : M.ifuncs()) {
1509     // IFUNC: [strtab offset, strtab size, ifunc type, address space, resolver
1510     //         val#, linkage, visibility, DSO_Local]
1511     Vals.push_back(addToStrtab(I.getName()));
1512     Vals.push_back(I.getName().size());
1513     Vals.push_back(VE.getTypeID(I.getValueType()));
1514     Vals.push_back(I.getType()->getAddressSpace());
1515     Vals.push_back(VE.getValueID(I.getResolver()));
1516     Vals.push_back(getEncodedLinkage(I));
1517     Vals.push_back(getEncodedVisibility(I));
1518     Vals.push_back(I.isDSOLocal());
1519     Vals.push_back(addToStrtab(I.getPartition()));
1520     Vals.push_back(I.getPartition().size());
1521     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
1522     Vals.clear();
1523   }
1524 
1525   writeValueSymbolTableForwardDecl();
1526 }
1527 
1528 static uint64_t getOptimizationFlags(const Value *V) {
1529   uint64_t Flags = 0;
1530 
1531   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
1532     if (OBO->hasNoSignedWrap())
1533       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
1534     if (OBO->hasNoUnsignedWrap())
1535       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
1536   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
1537     if (PEO->isExact())
1538       Flags |= 1 << bitc::PEO_EXACT;
1539   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
1540     if (FPMO->hasAllowReassoc())
1541       Flags |= bitc::AllowReassoc;
1542     if (FPMO->hasNoNaNs())
1543       Flags |= bitc::NoNaNs;
1544     if (FPMO->hasNoInfs())
1545       Flags |= bitc::NoInfs;
1546     if (FPMO->hasNoSignedZeros())
1547       Flags |= bitc::NoSignedZeros;
1548     if (FPMO->hasAllowReciprocal())
1549       Flags |= bitc::AllowReciprocal;
1550     if (FPMO->hasAllowContract())
1551       Flags |= bitc::AllowContract;
1552     if (FPMO->hasApproxFunc())
1553       Flags |= bitc::ApproxFunc;
1554   }
1555 
1556   return Flags;
1557 }
1558 
1559 void ModuleBitcodeWriter::writeValueAsMetadata(
1560     const ValueAsMetadata *MD, SmallVectorImpl<uint64_t> &Record) {
1561   // Mimic an MDNode with a value as one operand.
1562   Value *V = MD->getValue();
1563   Record.push_back(VE.getTypeID(V->getType()));
1564   Record.push_back(VE.getValueID(V));
1565   Stream.EmitRecord(bitc::METADATA_VALUE, Record, 0);
1566   Record.clear();
1567 }
1568 
1569 void ModuleBitcodeWriter::writeMDTuple(const MDTuple *N,
1570                                        SmallVectorImpl<uint64_t> &Record,
1571                                        unsigned Abbrev) {
1572   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
1573     Metadata *MD = N->getOperand(i);
1574     assert(!(MD && isa<LocalAsMetadata>(MD)) &&
1575            "Unexpected function-local metadata");
1576     Record.push_back(VE.getMetadataOrNullID(MD));
1577   }
1578   Stream.EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
1579                                     : bitc::METADATA_NODE,
1580                     Record, Abbrev);
1581   Record.clear();
1582 }
1583 
1584 unsigned ModuleBitcodeWriter::createDILocationAbbrev() {
1585   // Assume the column is usually under 128, and always output the inlined-at
1586   // location (it's never more expensive than building an array size 1).
1587   auto Abbv = std::make_shared<BitCodeAbbrev>();
1588   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
1589   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1590   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1591   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1592   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1593   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1594   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1595   return Stream.EmitAbbrev(std::move(Abbv));
1596 }
1597 
1598 void ModuleBitcodeWriter::writeDILocation(const DILocation *N,
1599                                           SmallVectorImpl<uint64_t> &Record,
1600                                           unsigned &Abbrev) {
1601   if (!Abbrev)
1602     Abbrev = createDILocationAbbrev();
1603 
1604   Record.push_back(N->isDistinct());
1605   Record.push_back(N->getLine());
1606   Record.push_back(N->getColumn());
1607   Record.push_back(VE.getMetadataID(N->getScope()));
1608   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
1609   Record.push_back(N->isImplicitCode());
1610 
1611   Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
1612   Record.clear();
1613 }
1614 
1615 unsigned ModuleBitcodeWriter::createGenericDINodeAbbrev() {
1616   // Assume the column is usually under 128, and always output the inlined-at
1617   // location (it's never more expensive than building an array size 1).
1618   auto Abbv = std::make_shared<BitCodeAbbrev>();
1619   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
1620   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1621   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1622   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1623   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1624   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1625   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1626   return Stream.EmitAbbrev(std::move(Abbv));
1627 }
1628 
1629 void ModuleBitcodeWriter::writeGenericDINode(const GenericDINode *N,
1630                                              SmallVectorImpl<uint64_t> &Record,
1631                                              unsigned &Abbrev) {
1632   if (!Abbrev)
1633     Abbrev = createGenericDINodeAbbrev();
1634 
1635   Record.push_back(N->isDistinct());
1636   Record.push_back(N->getTag());
1637   Record.push_back(0); // Per-tag version field; unused for now.
1638 
1639   for (auto &I : N->operands())
1640     Record.push_back(VE.getMetadataOrNullID(I));
1641 
1642   Stream.EmitRecord(bitc::METADATA_GENERIC_DEBUG, Record, Abbrev);
1643   Record.clear();
1644 }
1645 
1646 void ModuleBitcodeWriter::writeDISubrange(const DISubrange *N,
1647                                           SmallVectorImpl<uint64_t> &Record,
1648                                           unsigned Abbrev) {
1649   const uint64_t Version = 2 << 1;
1650   Record.push_back((uint64_t)N->isDistinct() | Version);
1651   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1652   Record.push_back(VE.getMetadataOrNullID(N->getRawLowerBound()));
1653   Record.push_back(VE.getMetadataOrNullID(N->getRawUpperBound()));
1654   Record.push_back(VE.getMetadataOrNullID(N->getRawStride()));
1655 
1656   Stream.EmitRecord(bitc::METADATA_SUBRANGE, Record, Abbrev);
1657   Record.clear();
1658 }
1659 
1660 void ModuleBitcodeWriter::writeDIGenericSubrange(
1661     const DIGenericSubrange *N, SmallVectorImpl<uint64_t> &Record,
1662     unsigned Abbrev) {
1663   Record.push_back((uint64_t)N->isDistinct());
1664   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1665   Record.push_back(VE.getMetadataOrNullID(N->getRawLowerBound()));
1666   Record.push_back(VE.getMetadataOrNullID(N->getRawUpperBound()));
1667   Record.push_back(VE.getMetadataOrNullID(N->getRawStride()));
1668 
1669   Stream.EmitRecord(bitc::METADATA_GENERIC_SUBRANGE, Record, Abbrev);
1670   Record.clear();
1671 }
1672 
1673 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
1674   if ((int64_t)V >= 0)
1675     Vals.push_back(V << 1);
1676   else
1677     Vals.push_back((-V << 1) | 1);
1678 }
1679 
1680 static void emitWideAPInt(SmallVectorImpl<uint64_t> &Vals, const APInt &A) {
1681   // We have an arbitrary precision integer value to write whose
1682   // bit width is > 64. However, in canonical unsigned integer
1683   // format it is likely that the high bits are going to be zero.
1684   // So, we only write the number of active words.
1685   unsigned NumWords = A.getActiveWords();
1686   const uint64_t *RawData = A.getRawData();
1687   for (unsigned i = 0; i < NumWords; i++)
1688     emitSignedInt64(Vals, RawData[i]);
1689 }
1690 
1691 void ModuleBitcodeWriter::writeDIEnumerator(const DIEnumerator *N,
1692                                             SmallVectorImpl<uint64_t> &Record,
1693                                             unsigned Abbrev) {
1694   const uint64_t IsBigInt = 1 << 2;
1695   Record.push_back(IsBigInt | (N->isUnsigned() << 1) | N->isDistinct());
1696   Record.push_back(N->getValue().getBitWidth());
1697   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1698   emitWideAPInt(Record, N->getValue());
1699 
1700   Stream.EmitRecord(bitc::METADATA_ENUMERATOR, Record, Abbrev);
1701   Record.clear();
1702 }
1703 
1704 void ModuleBitcodeWriter::writeDIBasicType(const DIBasicType *N,
1705                                            SmallVectorImpl<uint64_t> &Record,
1706                                            unsigned Abbrev) {
1707   Record.push_back(N->isDistinct());
1708   Record.push_back(N->getTag());
1709   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1710   Record.push_back(N->getSizeInBits());
1711   Record.push_back(N->getAlignInBits());
1712   Record.push_back(N->getEncoding());
1713   Record.push_back(N->getFlags());
1714 
1715   Stream.EmitRecord(bitc::METADATA_BASIC_TYPE, Record, Abbrev);
1716   Record.clear();
1717 }
1718 
1719 void ModuleBitcodeWriter::writeDIStringType(const DIStringType *N,
1720                                             SmallVectorImpl<uint64_t> &Record,
1721                                             unsigned Abbrev) {
1722   Record.push_back(N->isDistinct());
1723   Record.push_back(N->getTag());
1724   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1725   Record.push_back(VE.getMetadataOrNullID(N->getStringLength()));
1726   Record.push_back(VE.getMetadataOrNullID(N->getStringLengthExp()));
1727   Record.push_back(VE.getMetadataOrNullID(N->getStringLocationExp()));
1728   Record.push_back(N->getSizeInBits());
1729   Record.push_back(N->getAlignInBits());
1730   Record.push_back(N->getEncoding());
1731 
1732   Stream.EmitRecord(bitc::METADATA_STRING_TYPE, Record, Abbrev);
1733   Record.clear();
1734 }
1735 
1736 void ModuleBitcodeWriter::writeDIDerivedType(const DIDerivedType *N,
1737                                              SmallVectorImpl<uint64_t> &Record,
1738                                              unsigned Abbrev) {
1739   Record.push_back(N->isDistinct());
1740   Record.push_back(N->getTag());
1741   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1742   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1743   Record.push_back(N->getLine());
1744   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1745   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1746   Record.push_back(N->getSizeInBits());
1747   Record.push_back(N->getAlignInBits());
1748   Record.push_back(N->getOffsetInBits());
1749   Record.push_back(N->getFlags());
1750   Record.push_back(VE.getMetadataOrNullID(N->getExtraData()));
1751 
1752   // DWARF address space is encoded as N->getDWARFAddressSpace() + 1. 0 means
1753   // that there is no DWARF address space associated with DIDerivedType.
1754   if (const auto &DWARFAddressSpace = N->getDWARFAddressSpace())
1755     Record.push_back(*DWARFAddressSpace + 1);
1756   else
1757     Record.push_back(0);
1758 
1759   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1760 
1761   Stream.EmitRecord(bitc::METADATA_DERIVED_TYPE, Record, Abbrev);
1762   Record.clear();
1763 }
1764 
1765 void ModuleBitcodeWriter::writeDICompositeType(
1766     const DICompositeType *N, SmallVectorImpl<uint64_t> &Record,
1767     unsigned Abbrev) {
1768   const unsigned IsNotUsedInOldTypeRef = 0x2;
1769   Record.push_back(IsNotUsedInOldTypeRef | (unsigned)N->isDistinct());
1770   Record.push_back(N->getTag());
1771   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1772   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1773   Record.push_back(N->getLine());
1774   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1775   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1776   Record.push_back(N->getSizeInBits());
1777   Record.push_back(N->getAlignInBits());
1778   Record.push_back(N->getOffsetInBits());
1779   Record.push_back(N->getFlags());
1780   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1781   Record.push_back(N->getRuntimeLang());
1782   Record.push_back(VE.getMetadataOrNullID(N->getVTableHolder()));
1783   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1784   Record.push_back(VE.getMetadataOrNullID(N->getRawIdentifier()));
1785   Record.push_back(VE.getMetadataOrNullID(N->getDiscriminator()));
1786   Record.push_back(VE.getMetadataOrNullID(N->getRawDataLocation()));
1787   Record.push_back(VE.getMetadataOrNullID(N->getRawAssociated()));
1788   Record.push_back(VE.getMetadataOrNullID(N->getRawAllocated()));
1789   Record.push_back(VE.getMetadataOrNullID(N->getRawRank()));
1790   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1791 
1792   Stream.EmitRecord(bitc::METADATA_COMPOSITE_TYPE, Record, Abbrev);
1793   Record.clear();
1794 }
1795 
1796 void ModuleBitcodeWriter::writeDISubroutineType(
1797     const DISubroutineType *N, SmallVectorImpl<uint64_t> &Record,
1798     unsigned Abbrev) {
1799   const unsigned HasNoOldTypeRefs = 0x2;
1800   Record.push_back(HasNoOldTypeRefs | (unsigned)N->isDistinct());
1801   Record.push_back(N->getFlags());
1802   Record.push_back(VE.getMetadataOrNullID(N->getTypeArray().get()));
1803   Record.push_back(N->getCC());
1804 
1805   Stream.EmitRecord(bitc::METADATA_SUBROUTINE_TYPE, Record, Abbrev);
1806   Record.clear();
1807 }
1808 
1809 void ModuleBitcodeWriter::writeDIFile(const DIFile *N,
1810                                       SmallVectorImpl<uint64_t> &Record,
1811                                       unsigned Abbrev) {
1812   Record.push_back(N->isDistinct());
1813   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
1814   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
1815   if (N->getRawChecksum()) {
1816     Record.push_back(N->getRawChecksum()->Kind);
1817     Record.push_back(VE.getMetadataOrNullID(N->getRawChecksum()->Value));
1818   } else {
1819     // Maintain backwards compatibility with the old internal representation of
1820     // CSK_None in ChecksumKind by writing nulls here when Checksum is None.
1821     Record.push_back(0);
1822     Record.push_back(VE.getMetadataOrNullID(nullptr));
1823   }
1824   auto Source = N->getRawSource();
1825   if (Source)
1826     Record.push_back(VE.getMetadataOrNullID(Source));
1827 
1828   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
1829   Record.clear();
1830 }
1831 
1832 void ModuleBitcodeWriter::writeDICompileUnit(const DICompileUnit *N,
1833                                              SmallVectorImpl<uint64_t> &Record,
1834                                              unsigned Abbrev) {
1835   assert(N->isDistinct() && "Expected distinct compile units");
1836   Record.push_back(/* IsDistinct */ true);
1837   Record.push_back(N->getSourceLanguage());
1838   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1839   Record.push_back(VE.getMetadataOrNullID(N->getRawProducer()));
1840   Record.push_back(N->isOptimized());
1841   Record.push_back(VE.getMetadataOrNullID(N->getRawFlags()));
1842   Record.push_back(N->getRuntimeVersion());
1843   Record.push_back(VE.getMetadataOrNullID(N->getRawSplitDebugFilename()));
1844   Record.push_back(N->getEmissionKind());
1845   Record.push_back(VE.getMetadataOrNullID(N->getEnumTypes().get()));
1846   Record.push_back(VE.getMetadataOrNullID(N->getRetainedTypes().get()));
1847   Record.push_back(/* subprograms */ 0);
1848   Record.push_back(VE.getMetadataOrNullID(N->getGlobalVariables().get()));
1849   Record.push_back(VE.getMetadataOrNullID(N->getImportedEntities().get()));
1850   Record.push_back(N->getDWOId());
1851   Record.push_back(VE.getMetadataOrNullID(N->getMacros().get()));
1852   Record.push_back(N->getSplitDebugInlining());
1853   Record.push_back(N->getDebugInfoForProfiling());
1854   Record.push_back((unsigned)N->getNameTableKind());
1855   Record.push_back(N->getRangesBaseAddress());
1856   Record.push_back(VE.getMetadataOrNullID(N->getRawSysRoot()));
1857   Record.push_back(VE.getMetadataOrNullID(N->getRawSDK()));
1858 
1859   Stream.EmitRecord(bitc::METADATA_COMPILE_UNIT, Record, Abbrev);
1860   Record.clear();
1861 }
1862 
1863 void ModuleBitcodeWriter::writeDISubprogram(const DISubprogram *N,
1864                                             SmallVectorImpl<uint64_t> &Record,
1865                                             unsigned Abbrev) {
1866   const uint64_t HasUnitFlag = 1 << 1;
1867   const uint64_t HasSPFlagsFlag = 1 << 2;
1868   Record.push_back(uint64_t(N->isDistinct()) | HasUnitFlag | HasSPFlagsFlag);
1869   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1870   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1871   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1872   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1873   Record.push_back(N->getLine());
1874   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1875   Record.push_back(N->getScopeLine());
1876   Record.push_back(VE.getMetadataOrNullID(N->getContainingType()));
1877   Record.push_back(N->getSPFlags());
1878   Record.push_back(N->getVirtualIndex());
1879   Record.push_back(N->getFlags());
1880   Record.push_back(VE.getMetadataOrNullID(N->getRawUnit()));
1881   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1882   Record.push_back(VE.getMetadataOrNullID(N->getDeclaration()));
1883   Record.push_back(VE.getMetadataOrNullID(N->getRetainedNodes().get()));
1884   Record.push_back(N->getThisAdjustment());
1885   Record.push_back(VE.getMetadataOrNullID(N->getThrownTypes().get()));
1886   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1887   Record.push_back(VE.getMetadataOrNullID(N->getRawTargetFuncName()));
1888 
1889   Stream.EmitRecord(bitc::METADATA_SUBPROGRAM, Record, Abbrev);
1890   Record.clear();
1891 }
1892 
1893 void ModuleBitcodeWriter::writeDILexicalBlock(const DILexicalBlock *N,
1894                                               SmallVectorImpl<uint64_t> &Record,
1895                                               unsigned Abbrev) {
1896   Record.push_back(N->isDistinct());
1897   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1898   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1899   Record.push_back(N->getLine());
1900   Record.push_back(N->getColumn());
1901 
1902   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK, Record, Abbrev);
1903   Record.clear();
1904 }
1905 
1906 void ModuleBitcodeWriter::writeDILexicalBlockFile(
1907     const DILexicalBlockFile *N, SmallVectorImpl<uint64_t> &Record,
1908     unsigned Abbrev) {
1909   Record.push_back(N->isDistinct());
1910   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1911   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1912   Record.push_back(N->getDiscriminator());
1913 
1914   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK_FILE, Record, Abbrev);
1915   Record.clear();
1916 }
1917 
1918 void ModuleBitcodeWriter::writeDICommonBlock(const DICommonBlock *N,
1919                                              SmallVectorImpl<uint64_t> &Record,
1920                                              unsigned Abbrev) {
1921   Record.push_back(N->isDistinct());
1922   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1923   Record.push_back(VE.getMetadataOrNullID(N->getDecl()));
1924   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1925   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1926   Record.push_back(N->getLineNo());
1927 
1928   Stream.EmitRecord(bitc::METADATA_COMMON_BLOCK, Record, Abbrev);
1929   Record.clear();
1930 }
1931 
1932 void ModuleBitcodeWriter::writeDINamespace(const DINamespace *N,
1933                                            SmallVectorImpl<uint64_t> &Record,
1934                                            unsigned Abbrev) {
1935   Record.push_back(N->isDistinct() | N->getExportSymbols() << 1);
1936   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1937   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1938 
1939   Stream.EmitRecord(bitc::METADATA_NAMESPACE, Record, Abbrev);
1940   Record.clear();
1941 }
1942 
1943 void ModuleBitcodeWriter::writeDIMacro(const DIMacro *N,
1944                                        SmallVectorImpl<uint64_t> &Record,
1945                                        unsigned Abbrev) {
1946   Record.push_back(N->isDistinct());
1947   Record.push_back(N->getMacinfoType());
1948   Record.push_back(N->getLine());
1949   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1950   Record.push_back(VE.getMetadataOrNullID(N->getRawValue()));
1951 
1952   Stream.EmitRecord(bitc::METADATA_MACRO, Record, Abbrev);
1953   Record.clear();
1954 }
1955 
1956 void ModuleBitcodeWriter::writeDIMacroFile(const DIMacroFile *N,
1957                                            SmallVectorImpl<uint64_t> &Record,
1958                                            unsigned Abbrev) {
1959   Record.push_back(N->isDistinct());
1960   Record.push_back(N->getMacinfoType());
1961   Record.push_back(N->getLine());
1962   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1963   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1964 
1965   Stream.EmitRecord(bitc::METADATA_MACRO_FILE, Record, Abbrev);
1966   Record.clear();
1967 }
1968 
1969 void ModuleBitcodeWriter::writeDIArgList(const DIArgList *N,
1970                                          SmallVectorImpl<uint64_t> &Record,
1971                                          unsigned Abbrev) {
1972   Record.reserve(N->getArgs().size());
1973   for (ValueAsMetadata *MD : N->getArgs())
1974     Record.push_back(VE.getMetadataID(MD));
1975 
1976   Stream.EmitRecord(bitc::METADATA_ARG_LIST, Record, Abbrev);
1977   Record.clear();
1978 }
1979 
1980 void ModuleBitcodeWriter::writeDIModule(const DIModule *N,
1981                                         SmallVectorImpl<uint64_t> &Record,
1982                                         unsigned Abbrev) {
1983   Record.push_back(N->isDistinct());
1984   for (auto &I : N->operands())
1985     Record.push_back(VE.getMetadataOrNullID(I));
1986   Record.push_back(N->getLineNo());
1987   Record.push_back(N->getIsDecl());
1988 
1989   Stream.EmitRecord(bitc::METADATA_MODULE, Record, Abbrev);
1990   Record.clear();
1991 }
1992 
1993 void ModuleBitcodeWriter::writeDIAssignID(const DIAssignID *N,
1994                                           SmallVectorImpl<uint64_t> &Record,
1995                                           unsigned Abbrev) {
1996   // There are no arguments for this metadata type.
1997   Record.push_back(N->isDistinct());
1998   Stream.EmitRecord(bitc::METADATA_ASSIGN_ID, Record, Abbrev);
1999   Record.clear();
2000 }
2001 
2002 void ModuleBitcodeWriter::writeDITemplateTypeParameter(
2003     const DITemplateTypeParameter *N, SmallVectorImpl<uint64_t> &Record,
2004     unsigned Abbrev) {
2005   Record.push_back(N->isDistinct());
2006   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2007   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2008   Record.push_back(N->isDefault());
2009 
2010   Stream.EmitRecord(bitc::METADATA_TEMPLATE_TYPE, Record, Abbrev);
2011   Record.clear();
2012 }
2013 
2014 void ModuleBitcodeWriter::writeDITemplateValueParameter(
2015     const DITemplateValueParameter *N, SmallVectorImpl<uint64_t> &Record,
2016     unsigned Abbrev) {
2017   Record.push_back(N->isDistinct());
2018   Record.push_back(N->getTag());
2019   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2020   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2021   Record.push_back(N->isDefault());
2022   Record.push_back(VE.getMetadataOrNullID(N->getValue()));
2023 
2024   Stream.EmitRecord(bitc::METADATA_TEMPLATE_VALUE, Record, Abbrev);
2025   Record.clear();
2026 }
2027 
2028 void ModuleBitcodeWriter::writeDIGlobalVariable(
2029     const DIGlobalVariable *N, SmallVectorImpl<uint64_t> &Record,
2030     unsigned Abbrev) {
2031   const uint64_t Version = 2 << 1;
2032   Record.push_back((uint64_t)N->isDistinct() | Version);
2033   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2034   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2035   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
2036   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2037   Record.push_back(N->getLine());
2038   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2039   Record.push_back(N->isLocalToUnit());
2040   Record.push_back(N->isDefinition());
2041   Record.push_back(VE.getMetadataOrNullID(N->getStaticDataMemberDeclaration()));
2042   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams()));
2043   Record.push_back(N->getAlignInBits());
2044   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
2045 
2046   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR, Record, Abbrev);
2047   Record.clear();
2048 }
2049 
2050 void ModuleBitcodeWriter::writeDILocalVariable(
2051     const DILocalVariable *N, SmallVectorImpl<uint64_t> &Record,
2052     unsigned Abbrev) {
2053   // In order to support all possible bitcode formats in BitcodeReader we need
2054   // to distinguish the following cases:
2055   // 1) Record has no artificial tag (Record[1]),
2056   //   has no obsolete inlinedAt field (Record[9]).
2057   //   In this case Record size will be 8, HasAlignment flag is false.
2058   // 2) Record has artificial tag (Record[1]),
2059   //   has no obsolete inlignedAt field (Record[9]).
2060   //   In this case Record size will be 9, HasAlignment flag is false.
2061   // 3) Record has both artificial tag (Record[1]) and
2062   //   obsolete inlignedAt field (Record[9]).
2063   //   In this case Record size will be 10, HasAlignment flag is false.
2064   // 4) Record has neither artificial tag, nor inlignedAt field, but
2065   //   HasAlignment flag is true and Record[8] contains alignment value.
2066   const uint64_t HasAlignmentFlag = 1 << 1;
2067   Record.push_back((uint64_t)N->isDistinct() | HasAlignmentFlag);
2068   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2069   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2070   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2071   Record.push_back(N->getLine());
2072   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2073   Record.push_back(N->getArg());
2074   Record.push_back(N->getFlags());
2075   Record.push_back(N->getAlignInBits());
2076   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
2077 
2078   Stream.EmitRecord(bitc::METADATA_LOCAL_VAR, Record, Abbrev);
2079   Record.clear();
2080 }
2081 
2082 void ModuleBitcodeWriter::writeDILabel(
2083     const DILabel *N, SmallVectorImpl<uint64_t> &Record,
2084     unsigned Abbrev) {
2085   Record.push_back((uint64_t)N->isDistinct());
2086   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2087   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2088   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2089   Record.push_back(N->getLine());
2090 
2091   Stream.EmitRecord(bitc::METADATA_LABEL, Record, Abbrev);
2092   Record.clear();
2093 }
2094 
2095 void ModuleBitcodeWriter::writeDIExpression(const DIExpression *N,
2096                                             SmallVectorImpl<uint64_t> &Record,
2097                                             unsigned Abbrev) {
2098   Record.reserve(N->getElements().size() + 1);
2099   const uint64_t Version = 3 << 1;
2100   Record.push_back((uint64_t)N->isDistinct() | Version);
2101   Record.append(N->elements_begin(), N->elements_end());
2102 
2103   Stream.EmitRecord(bitc::METADATA_EXPRESSION, Record, Abbrev);
2104   Record.clear();
2105 }
2106 
2107 void ModuleBitcodeWriter::writeDIGlobalVariableExpression(
2108     const DIGlobalVariableExpression *N, SmallVectorImpl<uint64_t> &Record,
2109     unsigned Abbrev) {
2110   Record.push_back(N->isDistinct());
2111   Record.push_back(VE.getMetadataOrNullID(N->getVariable()));
2112   Record.push_back(VE.getMetadataOrNullID(N->getExpression()));
2113 
2114   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR_EXPR, Record, Abbrev);
2115   Record.clear();
2116 }
2117 
2118 void ModuleBitcodeWriter::writeDIObjCProperty(const DIObjCProperty *N,
2119                                               SmallVectorImpl<uint64_t> &Record,
2120                                               unsigned Abbrev) {
2121   Record.push_back(N->isDistinct());
2122   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2123   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2124   Record.push_back(N->getLine());
2125   Record.push_back(VE.getMetadataOrNullID(N->getRawSetterName()));
2126   Record.push_back(VE.getMetadataOrNullID(N->getRawGetterName()));
2127   Record.push_back(N->getAttributes());
2128   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2129 
2130   Stream.EmitRecord(bitc::METADATA_OBJC_PROPERTY, Record, Abbrev);
2131   Record.clear();
2132 }
2133 
2134 void ModuleBitcodeWriter::writeDIImportedEntity(
2135     const DIImportedEntity *N, SmallVectorImpl<uint64_t> &Record,
2136     unsigned Abbrev) {
2137   Record.push_back(N->isDistinct());
2138   Record.push_back(N->getTag());
2139   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2140   Record.push_back(VE.getMetadataOrNullID(N->getEntity()));
2141   Record.push_back(N->getLine());
2142   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2143   Record.push_back(VE.getMetadataOrNullID(N->getRawFile()));
2144   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
2145 
2146   Stream.EmitRecord(bitc::METADATA_IMPORTED_ENTITY, Record, Abbrev);
2147   Record.clear();
2148 }
2149 
2150 unsigned ModuleBitcodeWriter::createNamedMetadataAbbrev() {
2151   auto Abbv = std::make_shared<BitCodeAbbrev>();
2152   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
2153   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2154   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2155   return Stream.EmitAbbrev(std::move(Abbv));
2156 }
2157 
2158 void ModuleBitcodeWriter::writeNamedMetadata(
2159     SmallVectorImpl<uint64_t> &Record) {
2160   if (M.named_metadata_empty())
2161     return;
2162 
2163   unsigned Abbrev = createNamedMetadataAbbrev();
2164   for (const NamedMDNode &NMD : M.named_metadata()) {
2165     // Write name.
2166     StringRef Str = NMD.getName();
2167     Record.append(Str.bytes_begin(), Str.bytes_end());
2168     Stream.EmitRecord(bitc::METADATA_NAME, Record, Abbrev);
2169     Record.clear();
2170 
2171     // Write named metadata operands.
2172     for (const MDNode *N : NMD.operands())
2173       Record.push_back(VE.getMetadataID(N));
2174     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
2175     Record.clear();
2176   }
2177 }
2178 
2179 unsigned ModuleBitcodeWriter::createMetadataStringsAbbrev() {
2180   auto Abbv = std::make_shared<BitCodeAbbrev>();
2181   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRINGS));
2182   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // # of strings
2183   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // offset to chars
2184   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
2185   return Stream.EmitAbbrev(std::move(Abbv));
2186 }
2187 
2188 /// Write out a record for MDString.
2189 ///
2190 /// All the metadata strings in a metadata block are emitted in a single
2191 /// record.  The sizes and strings themselves are shoved into a blob.
2192 void ModuleBitcodeWriter::writeMetadataStrings(
2193     ArrayRef<const Metadata *> Strings, SmallVectorImpl<uint64_t> &Record) {
2194   if (Strings.empty())
2195     return;
2196 
2197   // Start the record with the number of strings.
2198   Record.push_back(bitc::METADATA_STRINGS);
2199   Record.push_back(Strings.size());
2200 
2201   // Emit the sizes of the strings in the blob.
2202   SmallString<256> Blob;
2203   {
2204     BitstreamWriter W(Blob);
2205     for (const Metadata *MD : Strings)
2206       W.EmitVBR(cast<MDString>(MD)->getLength(), 6);
2207     W.FlushToWord();
2208   }
2209 
2210   // Add the offset to the strings to the record.
2211   Record.push_back(Blob.size());
2212 
2213   // Add the strings to the blob.
2214   for (const Metadata *MD : Strings)
2215     Blob.append(cast<MDString>(MD)->getString());
2216 
2217   // Emit the final record.
2218   Stream.EmitRecordWithBlob(createMetadataStringsAbbrev(), Record, Blob);
2219   Record.clear();
2220 }
2221 
2222 // Generates an enum to use as an index in the Abbrev array of Metadata record.
2223 enum MetadataAbbrev : unsigned {
2224 #define HANDLE_MDNODE_LEAF(CLASS) CLASS##AbbrevID,
2225 #include "llvm/IR/Metadata.def"
2226   LastPlusOne
2227 };
2228 
2229 void ModuleBitcodeWriter::writeMetadataRecords(
2230     ArrayRef<const Metadata *> MDs, SmallVectorImpl<uint64_t> &Record,
2231     std::vector<unsigned> *MDAbbrevs, std::vector<uint64_t> *IndexPos) {
2232   if (MDs.empty())
2233     return;
2234 
2235   // Initialize MDNode abbreviations.
2236 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
2237 #include "llvm/IR/Metadata.def"
2238 
2239   for (const Metadata *MD : MDs) {
2240     if (IndexPos)
2241       IndexPos->push_back(Stream.GetCurrentBitNo());
2242     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
2243       assert(N->isResolved() && "Expected forward references to be resolved");
2244 
2245       switch (N->getMetadataID()) {
2246       default:
2247         llvm_unreachable("Invalid MDNode subclass");
2248 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
2249   case Metadata::CLASS##Kind:                                                  \
2250     if (MDAbbrevs)                                                             \
2251       write##CLASS(cast<CLASS>(N), Record,                                     \
2252                    (*MDAbbrevs)[MetadataAbbrev::CLASS##AbbrevID]);             \
2253     else                                                                       \
2254       write##CLASS(cast<CLASS>(N), Record, CLASS##Abbrev);                     \
2255     continue;
2256 #include "llvm/IR/Metadata.def"
2257       }
2258     }
2259     writeValueAsMetadata(cast<ValueAsMetadata>(MD), Record);
2260   }
2261 }
2262 
2263 void ModuleBitcodeWriter::writeModuleMetadata() {
2264   if (!VE.hasMDs() && M.named_metadata_empty())
2265     return;
2266 
2267   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 4);
2268   SmallVector<uint64_t, 64> Record;
2269 
2270   // Emit all abbrevs upfront, so that the reader can jump in the middle of the
2271   // block and load any metadata.
2272   std::vector<unsigned> MDAbbrevs;
2273 
2274   MDAbbrevs.resize(MetadataAbbrev::LastPlusOne);
2275   MDAbbrevs[MetadataAbbrev::DILocationAbbrevID] = createDILocationAbbrev();
2276   MDAbbrevs[MetadataAbbrev::GenericDINodeAbbrevID] =
2277       createGenericDINodeAbbrev();
2278 
2279   auto Abbv = std::make_shared<BitCodeAbbrev>();
2280   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX_OFFSET));
2281   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2282   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2283   unsigned OffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2284 
2285   Abbv = std::make_shared<BitCodeAbbrev>();
2286   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX));
2287   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2288   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2289   unsigned IndexAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2290 
2291   // Emit MDStrings together upfront.
2292   writeMetadataStrings(VE.getMDStrings(), Record);
2293 
2294   // We only emit an index for the metadata record if we have more than a given
2295   // (naive) threshold of metadatas, otherwise it is not worth it.
2296   if (VE.getNonMDStrings().size() > IndexThreshold) {
2297     // Write a placeholder value in for the offset of the metadata index,
2298     // which is written after the records, so that it can include
2299     // the offset of each entry. The placeholder offset will be
2300     // updated after all records are emitted.
2301     uint64_t Vals[] = {0, 0};
2302     Stream.EmitRecord(bitc::METADATA_INDEX_OFFSET, Vals, OffsetAbbrev);
2303   }
2304 
2305   // Compute and save the bit offset to the current position, which will be
2306   // patched when we emit the index later. We can simply subtract the 64-bit
2307   // fixed size from the current bit number to get the location to backpatch.
2308   uint64_t IndexOffsetRecordBitPos = Stream.GetCurrentBitNo();
2309 
2310   // This index will contain the bitpos for each individual record.
2311   std::vector<uint64_t> IndexPos;
2312   IndexPos.reserve(VE.getNonMDStrings().size());
2313 
2314   // Write all the records
2315   writeMetadataRecords(VE.getNonMDStrings(), Record, &MDAbbrevs, &IndexPos);
2316 
2317   if (VE.getNonMDStrings().size() > IndexThreshold) {
2318     // Now that we have emitted all the records we will emit the index. But
2319     // first
2320     // backpatch the forward reference so that the reader can skip the records
2321     // efficiently.
2322     Stream.BackpatchWord64(IndexOffsetRecordBitPos - 64,
2323                            Stream.GetCurrentBitNo() - IndexOffsetRecordBitPos);
2324 
2325     // Delta encode the index.
2326     uint64_t PreviousValue = IndexOffsetRecordBitPos;
2327     for (auto &Elt : IndexPos) {
2328       auto EltDelta = Elt - PreviousValue;
2329       PreviousValue = Elt;
2330       Elt = EltDelta;
2331     }
2332     // Emit the index record.
2333     Stream.EmitRecord(bitc::METADATA_INDEX, IndexPos, IndexAbbrev);
2334     IndexPos.clear();
2335   }
2336 
2337   // Write the named metadata now.
2338   writeNamedMetadata(Record);
2339 
2340   auto AddDeclAttachedMetadata = [&](const GlobalObject &GO) {
2341     SmallVector<uint64_t, 4> Record;
2342     Record.push_back(VE.getValueID(&GO));
2343     pushGlobalMetadataAttachment(Record, GO);
2344     Stream.EmitRecord(bitc::METADATA_GLOBAL_DECL_ATTACHMENT, Record);
2345   };
2346   for (const Function &F : M)
2347     if (F.isDeclaration() && F.hasMetadata())
2348       AddDeclAttachedMetadata(F);
2349   // FIXME: Only store metadata for declarations here, and move data for global
2350   // variable definitions to a separate block (PR28134).
2351   for (const GlobalVariable &GV : M.globals())
2352     if (GV.hasMetadata())
2353       AddDeclAttachedMetadata(GV);
2354 
2355   Stream.ExitBlock();
2356 }
2357 
2358 void ModuleBitcodeWriter::writeFunctionMetadata(const Function &F) {
2359   if (!VE.hasMDs())
2360     return;
2361 
2362   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
2363   SmallVector<uint64_t, 64> Record;
2364   writeMetadataStrings(VE.getMDStrings(), Record);
2365   writeMetadataRecords(VE.getNonMDStrings(), Record);
2366   Stream.ExitBlock();
2367 }
2368 
2369 void ModuleBitcodeWriter::pushGlobalMetadataAttachment(
2370     SmallVectorImpl<uint64_t> &Record, const GlobalObject &GO) {
2371   // [n x [id, mdnode]]
2372   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2373   GO.getAllMetadata(MDs);
2374   for (const auto &I : MDs) {
2375     Record.push_back(I.first);
2376     Record.push_back(VE.getMetadataID(I.second));
2377   }
2378 }
2379 
2380 void ModuleBitcodeWriter::writeFunctionMetadataAttachment(const Function &F) {
2381   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
2382 
2383   SmallVector<uint64_t, 64> Record;
2384 
2385   if (F.hasMetadata()) {
2386     pushGlobalMetadataAttachment(Record, F);
2387     Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2388     Record.clear();
2389   }
2390 
2391   // Write metadata attachments
2392   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
2393   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2394   for (const BasicBlock &BB : F)
2395     for (const Instruction &I : BB) {
2396       MDs.clear();
2397       I.getAllMetadataOtherThanDebugLoc(MDs);
2398 
2399       // If no metadata, ignore instruction.
2400       if (MDs.empty()) continue;
2401 
2402       Record.push_back(VE.getInstructionID(&I));
2403 
2404       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
2405         Record.push_back(MDs[i].first);
2406         Record.push_back(VE.getMetadataID(MDs[i].second));
2407       }
2408       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2409       Record.clear();
2410     }
2411 
2412   Stream.ExitBlock();
2413 }
2414 
2415 void ModuleBitcodeWriter::writeModuleMetadataKinds() {
2416   SmallVector<uint64_t, 64> Record;
2417 
2418   // Write metadata kinds
2419   // METADATA_KIND - [n x [id, name]]
2420   SmallVector<StringRef, 8> Names;
2421   M.getMDKindNames(Names);
2422 
2423   if (Names.empty()) return;
2424 
2425   Stream.EnterSubblock(bitc::METADATA_KIND_BLOCK_ID, 3);
2426 
2427   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
2428     Record.push_back(MDKindID);
2429     StringRef KName = Names[MDKindID];
2430     Record.append(KName.begin(), KName.end());
2431 
2432     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
2433     Record.clear();
2434   }
2435 
2436   Stream.ExitBlock();
2437 }
2438 
2439 void ModuleBitcodeWriter::writeOperandBundleTags() {
2440   // Write metadata kinds
2441   //
2442   // OPERAND_BUNDLE_TAGS_BLOCK_ID : N x OPERAND_BUNDLE_TAG
2443   //
2444   // OPERAND_BUNDLE_TAG - [strchr x N]
2445 
2446   SmallVector<StringRef, 8> Tags;
2447   M.getOperandBundleTags(Tags);
2448 
2449   if (Tags.empty())
2450     return;
2451 
2452   Stream.EnterSubblock(bitc::OPERAND_BUNDLE_TAGS_BLOCK_ID, 3);
2453 
2454   SmallVector<uint64_t, 64> Record;
2455 
2456   for (auto Tag : Tags) {
2457     Record.append(Tag.begin(), Tag.end());
2458 
2459     Stream.EmitRecord(bitc::OPERAND_BUNDLE_TAG, Record, 0);
2460     Record.clear();
2461   }
2462 
2463   Stream.ExitBlock();
2464 }
2465 
2466 void ModuleBitcodeWriter::writeSyncScopeNames() {
2467   SmallVector<StringRef, 8> SSNs;
2468   M.getContext().getSyncScopeNames(SSNs);
2469   if (SSNs.empty())
2470     return;
2471 
2472   Stream.EnterSubblock(bitc::SYNC_SCOPE_NAMES_BLOCK_ID, 2);
2473 
2474   SmallVector<uint64_t, 64> Record;
2475   for (auto SSN : SSNs) {
2476     Record.append(SSN.begin(), SSN.end());
2477     Stream.EmitRecord(bitc::SYNC_SCOPE_NAME, Record, 0);
2478     Record.clear();
2479   }
2480 
2481   Stream.ExitBlock();
2482 }
2483 
2484 void ModuleBitcodeWriter::writeConstants(unsigned FirstVal, unsigned LastVal,
2485                                          bool isGlobal) {
2486   if (FirstVal == LastVal) return;
2487 
2488   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
2489 
2490   unsigned AggregateAbbrev = 0;
2491   unsigned String8Abbrev = 0;
2492   unsigned CString7Abbrev = 0;
2493   unsigned CString6Abbrev = 0;
2494   // If this is a constant pool for the module, emit module-specific abbrevs.
2495   if (isGlobal) {
2496     // Abbrev for CST_CODE_AGGREGATE.
2497     auto Abbv = std::make_shared<BitCodeAbbrev>();
2498     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
2499     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2500     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
2501     AggregateAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2502 
2503     // Abbrev for CST_CODE_STRING.
2504     Abbv = std::make_shared<BitCodeAbbrev>();
2505     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
2506     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2507     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2508     String8Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2509     // Abbrev for CST_CODE_CSTRING.
2510     Abbv = std::make_shared<BitCodeAbbrev>();
2511     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2512     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2513     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2514     CString7Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2515     // Abbrev for CST_CODE_CSTRING.
2516     Abbv = std::make_shared<BitCodeAbbrev>();
2517     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2518     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2519     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2520     CString6Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2521   }
2522 
2523   SmallVector<uint64_t, 64> Record;
2524 
2525   const ValueEnumerator::ValueList &Vals = VE.getValues();
2526   Type *LastTy = nullptr;
2527   for (unsigned i = FirstVal; i != LastVal; ++i) {
2528     const Value *V = Vals[i].first;
2529     // If we need to switch types, do so now.
2530     if (V->getType() != LastTy) {
2531       LastTy = V->getType();
2532       Record.push_back(VE.getTypeID(LastTy));
2533       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
2534                         CONSTANTS_SETTYPE_ABBREV);
2535       Record.clear();
2536     }
2537 
2538     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
2539       Record.push_back(VE.getTypeID(IA->getFunctionType()));
2540       Record.push_back(
2541           unsigned(IA->hasSideEffects()) | unsigned(IA->isAlignStack()) << 1 |
2542           unsigned(IA->getDialect() & 1) << 2 | unsigned(IA->canThrow()) << 3);
2543 
2544       // Add the asm string.
2545       const std::string &AsmStr = IA->getAsmString();
2546       Record.push_back(AsmStr.size());
2547       Record.append(AsmStr.begin(), AsmStr.end());
2548 
2549       // Add the constraint string.
2550       const std::string &ConstraintStr = IA->getConstraintString();
2551       Record.push_back(ConstraintStr.size());
2552       Record.append(ConstraintStr.begin(), ConstraintStr.end());
2553       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
2554       Record.clear();
2555       continue;
2556     }
2557     const Constant *C = cast<Constant>(V);
2558     unsigned Code = -1U;
2559     unsigned AbbrevToUse = 0;
2560     if (C->isNullValue()) {
2561       Code = bitc::CST_CODE_NULL;
2562     } else if (isa<PoisonValue>(C)) {
2563       Code = bitc::CST_CODE_POISON;
2564     } else if (isa<UndefValue>(C)) {
2565       Code = bitc::CST_CODE_UNDEF;
2566     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
2567       if (IV->getBitWidth() <= 64) {
2568         uint64_t V = IV->getSExtValue();
2569         emitSignedInt64(Record, V);
2570         Code = bitc::CST_CODE_INTEGER;
2571         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
2572       } else {                             // Wide integers, > 64 bits in size.
2573         emitWideAPInt(Record, IV->getValue());
2574         Code = bitc::CST_CODE_WIDE_INTEGER;
2575       }
2576     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
2577       Code = bitc::CST_CODE_FLOAT;
2578       Type *Ty = CFP->getType();
2579       if (Ty->isHalfTy() || Ty->isBFloatTy() || Ty->isFloatTy() ||
2580           Ty->isDoubleTy()) {
2581         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
2582       } else if (Ty->isX86_FP80Ty()) {
2583         // api needed to prevent premature destruction
2584         // bits are not in the same order as a normal i80 APInt, compensate.
2585         APInt api = CFP->getValueAPF().bitcastToAPInt();
2586         const uint64_t *p = api.getRawData();
2587         Record.push_back((p[1] << 48) | (p[0] >> 16));
2588         Record.push_back(p[0] & 0xffffLL);
2589       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
2590         APInt api = CFP->getValueAPF().bitcastToAPInt();
2591         const uint64_t *p = api.getRawData();
2592         Record.push_back(p[0]);
2593         Record.push_back(p[1]);
2594       } else {
2595         assert(0 && "Unknown FP type!");
2596       }
2597     } else if (isa<ConstantDataSequential>(C) &&
2598                cast<ConstantDataSequential>(C)->isString()) {
2599       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
2600       // Emit constant strings specially.
2601       unsigned NumElts = Str->getNumElements();
2602       // If this is a null-terminated string, use the denser CSTRING encoding.
2603       if (Str->isCString()) {
2604         Code = bitc::CST_CODE_CSTRING;
2605         --NumElts;  // Don't encode the null, which isn't allowed by char6.
2606       } else {
2607         Code = bitc::CST_CODE_STRING;
2608         AbbrevToUse = String8Abbrev;
2609       }
2610       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
2611       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
2612       for (unsigned i = 0; i != NumElts; ++i) {
2613         unsigned char V = Str->getElementAsInteger(i);
2614         Record.push_back(V);
2615         isCStr7 &= (V & 128) == 0;
2616         if (isCStrChar6)
2617           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
2618       }
2619 
2620       if (isCStrChar6)
2621         AbbrevToUse = CString6Abbrev;
2622       else if (isCStr7)
2623         AbbrevToUse = CString7Abbrev;
2624     } else if (const ConstantDataSequential *CDS =
2625                   dyn_cast<ConstantDataSequential>(C)) {
2626       Code = bitc::CST_CODE_DATA;
2627       Type *EltTy = CDS->getElementType();
2628       if (isa<IntegerType>(EltTy)) {
2629         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2630           Record.push_back(CDS->getElementAsInteger(i));
2631       } else {
2632         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2633           Record.push_back(
2634               CDS->getElementAsAPFloat(i).bitcastToAPInt().getLimitedValue());
2635       }
2636     } else if (isa<ConstantAggregate>(C)) {
2637       Code = bitc::CST_CODE_AGGREGATE;
2638       for (const Value *Op : C->operands())
2639         Record.push_back(VE.getValueID(Op));
2640       AbbrevToUse = AggregateAbbrev;
2641     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
2642       switch (CE->getOpcode()) {
2643       default:
2644         if (Instruction::isCast(CE->getOpcode())) {
2645           Code = bitc::CST_CODE_CE_CAST;
2646           Record.push_back(getEncodedCastOpcode(CE->getOpcode()));
2647           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2648           Record.push_back(VE.getValueID(C->getOperand(0)));
2649           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
2650         } else {
2651           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
2652           Code = bitc::CST_CODE_CE_BINOP;
2653           Record.push_back(getEncodedBinaryOpcode(CE->getOpcode()));
2654           Record.push_back(VE.getValueID(C->getOperand(0)));
2655           Record.push_back(VE.getValueID(C->getOperand(1)));
2656           uint64_t Flags = getOptimizationFlags(CE);
2657           if (Flags != 0)
2658             Record.push_back(Flags);
2659         }
2660         break;
2661       case Instruction::FNeg: {
2662         assert(CE->getNumOperands() == 1 && "Unknown constant expr!");
2663         Code = bitc::CST_CODE_CE_UNOP;
2664         Record.push_back(getEncodedUnaryOpcode(CE->getOpcode()));
2665         Record.push_back(VE.getValueID(C->getOperand(0)));
2666         uint64_t Flags = getOptimizationFlags(CE);
2667         if (Flags != 0)
2668           Record.push_back(Flags);
2669         break;
2670       }
2671       case Instruction::GetElementPtr: {
2672         Code = bitc::CST_CODE_CE_GEP;
2673         const auto *GO = cast<GEPOperator>(C);
2674         Record.push_back(VE.getTypeID(GO->getSourceElementType()));
2675         if (std::optional<unsigned> Idx = GO->getInRangeIndex()) {
2676           Code = bitc::CST_CODE_CE_GEP_WITH_INRANGE_INDEX;
2677           Record.push_back((*Idx << 1) | GO->isInBounds());
2678         } else if (GO->isInBounds())
2679           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
2680         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
2681           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
2682           Record.push_back(VE.getValueID(C->getOperand(i)));
2683         }
2684         break;
2685       }
2686       case Instruction::ExtractElement:
2687         Code = bitc::CST_CODE_CE_EXTRACTELT;
2688         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2689         Record.push_back(VE.getValueID(C->getOperand(0)));
2690         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
2691         Record.push_back(VE.getValueID(C->getOperand(1)));
2692         break;
2693       case Instruction::InsertElement:
2694         Code = bitc::CST_CODE_CE_INSERTELT;
2695         Record.push_back(VE.getValueID(C->getOperand(0)));
2696         Record.push_back(VE.getValueID(C->getOperand(1)));
2697         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
2698         Record.push_back(VE.getValueID(C->getOperand(2)));
2699         break;
2700       case Instruction::ShuffleVector:
2701         // If the return type and argument types are the same, this is a
2702         // standard shufflevector instruction.  If the types are different,
2703         // then the shuffle is widening or truncating the input vectors, and
2704         // the argument type must also be encoded.
2705         if (C->getType() == C->getOperand(0)->getType()) {
2706           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
2707         } else {
2708           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
2709           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2710         }
2711         Record.push_back(VE.getValueID(C->getOperand(0)));
2712         Record.push_back(VE.getValueID(C->getOperand(1)));
2713         Record.push_back(VE.getValueID(CE->getShuffleMaskForBitcode()));
2714         break;
2715       case Instruction::ICmp:
2716       case Instruction::FCmp:
2717         Code = bitc::CST_CODE_CE_CMP;
2718         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2719         Record.push_back(VE.getValueID(C->getOperand(0)));
2720         Record.push_back(VE.getValueID(C->getOperand(1)));
2721         Record.push_back(CE->getPredicate());
2722         break;
2723       }
2724     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
2725       Code = bitc::CST_CODE_BLOCKADDRESS;
2726       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
2727       Record.push_back(VE.getValueID(BA->getFunction()));
2728       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
2729     } else if (const auto *Equiv = dyn_cast<DSOLocalEquivalent>(C)) {
2730       Code = bitc::CST_CODE_DSO_LOCAL_EQUIVALENT;
2731       Record.push_back(VE.getTypeID(Equiv->getGlobalValue()->getType()));
2732       Record.push_back(VE.getValueID(Equiv->getGlobalValue()));
2733     } else if (const auto *NC = dyn_cast<NoCFIValue>(C)) {
2734       Code = bitc::CST_CODE_NO_CFI_VALUE;
2735       Record.push_back(VE.getTypeID(NC->getGlobalValue()->getType()));
2736       Record.push_back(VE.getValueID(NC->getGlobalValue()));
2737     } else {
2738 #ifndef NDEBUG
2739       C->dump();
2740 #endif
2741       llvm_unreachable("Unknown constant!");
2742     }
2743     Stream.EmitRecord(Code, Record, AbbrevToUse);
2744     Record.clear();
2745   }
2746 
2747   Stream.ExitBlock();
2748 }
2749 
2750 void ModuleBitcodeWriter::writeModuleConstants() {
2751   const ValueEnumerator::ValueList &Vals = VE.getValues();
2752 
2753   // Find the first constant to emit, which is the first non-globalvalue value.
2754   // We know globalvalues have been emitted by WriteModuleInfo.
2755   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
2756     if (!isa<GlobalValue>(Vals[i].first)) {
2757       writeConstants(i, Vals.size(), true);
2758       return;
2759     }
2760   }
2761 }
2762 
2763 /// pushValueAndType - The file has to encode both the value and type id for
2764 /// many values, because we need to know what type to create for forward
2765 /// references.  However, most operands are not forward references, so this type
2766 /// field is not needed.
2767 ///
2768 /// This function adds V's value ID to Vals.  If the value ID is higher than the
2769 /// instruction ID, then it is a forward reference, and it also includes the
2770 /// type ID.  The value ID that is written is encoded relative to the InstID.
2771 bool ModuleBitcodeWriter::pushValueAndType(const Value *V, unsigned InstID,
2772                                            SmallVectorImpl<unsigned> &Vals) {
2773   unsigned ValID = VE.getValueID(V);
2774   // Make encoding relative to the InstID.
2775   Vals.push_back(InstID - ValID);
2776   if (ValID >= InstID) {
2777     Vals.push_back(VE.getTypeID(V->getType()));
2778     return true;
2779   }
2780   return false;
2781 }
2782 
2783 void ModuleBitcodeWriter::writeOperandBundles(const CallBase &CS,
2784                                               unsigned InstID) {
2785   SmallVector<unsigned, 64> Record;
2786   LLVMContext &C = CS.getContext();
2787 
2788   for (unsigned i = 0, e = CS.getNumOperandBundles(); i != e; ++i) {
2789     const auto &Bundle = CS.getOperandBundleAt(i);
2790     Record.push_back(C.getOperandBundleTagID(Bundle.getTagName()));
2791 
2792     for (auto &Input : Bundle.Inputs)
2793       pushValueAndType(Input, InstID, Record);
2794 
2795     Stream.EmitRecord(bitc::FUNC_CODE_OPERAND_BUNDLE, Record);
2796     Record.clear();
2797   }
2798 }
2799 
2800 /// pushValue - Like pushValueAndType, but where the type of the value is
2801 /// omitted (perhaps it was already encoded in an earlier operand).
2802 void ModuleBitcodeWriter::pushValue(const Value *V, unsigned InstID,
2803                                     SmallVectorImpl<unsigned> &Vals) {
2804   unsigned ValID = VE.getValueID(V);
2805   Vals.push_back(InstID - ValID);
2806 }
2807 
2808 void ModuleBitcodeWriter::pushValueSigned(const Value *V, unsigned InstID,
2809                                           SmallVectorImpl<uint64_t> &Vals) {
2810   unsigned ValID = VE.getValueID(V);
2811   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
2812   emitSignedInt64(Vals, diff);
2813 }
2814 
2815 /// WriteInstruction - Emit an instruction to the specified stream.
2816 void ModuleBitcodeWriter::writeInstruction(const Instruction &I,
2817                                            unsigned InstID,
2818                                            SmallVectorImpl<unsigned> &Vals) {
2819   unsigned Code = 0;
2820   unsigned AbbrevToUse = 0;
2821   VE.setInstructionID(&I);
2822   switch (I.getOpcode()) {
2823   default:
2824     if (Instruction::isCast(I.getOpcode())) {
2825       Code = bitc::FUNC_CODE_INST_CAST;
2826       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2827         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
2828       Vals.push_back(VE.getTypeID(I.getType()));
2829       Vals.push_back(getEncodedCastOpcode(I.getOpcode()));
2830     } else {
2831       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
2832       Code = bitc::FUNC_CODE_INST_BINOP;
2833       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2834         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
2835       pushValue(I.getOperand(1), InstID, Vals);
2836       Vals.push_back(getEncodedBinaryOpcode(I.getOpcode()));
2837       uint64_t Flags = getOptimizationFlags(&I);
2838       if (Flags != 0) {
2839         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
2840           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
2841         Vals.push_back(Flags);
2842       }
2843     }
2844     break;
2845   case Instruction::FNeg: {
2846     Code = bitc::FUNC_CODE_INST_UNOP;
2847     if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2848       AbbrevToUse = FUNCTION_INST_UNOP_ABBREV;
2849     Vals.push_back(getEncodedUnaryOpcode(I.getOpcode()));
2850     uint64_t Flags = getOptimizationFlags(&I);
2851     if (Flags != 0) {
2852       if (AbbrevToUse == FUNCTION_INST_UNOP_ABBREV)
2853         AbbrevToUse = FUNCTION_INST_UNOP_FLAGS_ABBREV;
2854       Vals.push_back(Flags);
2855     }
2856     break;
2857   }
2858   case Instruction::GetElementPtr: {
2859     Code = bitc::FUNC_CODE_INST_GEP;
2860     AbbrevToUse = FUNCTION_INST_GEP_ABBREV;
2861     auto &GEPInst = cast<GetElementPtrInst>(I);
2862     Vals.push_back(GEPInst.isInBounds());
2863     Vals.push_back(VE.getTypeID(GEPInst.getSourceElementType()));
2864     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
2865       pushValueAndType(I.getOperand(i), InstID, Vals);
2866     break;
2867   }
2868   case Instruction::ExtractValue: {
2869     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
2870     pushValueAndType(I.getOperand(0), InstID, Vals);
2871     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
2872     Vals.append(EVI->idx_begin(), EVI->idx_end());
2873     break;
2874   }
2875   case Instruction::InsertValue: {
2876     Code = bitc::FUNC_CODE_INST_INSERTVAL;
2877     pushValueAndType(I.getOperand(0), InstID, Vals);
2878     pushValueAndType(I.getOperand(1), InstID, Vals);
2879     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
2880     Vals.append(IVI->idx_begin(), IVI->idx_end());
2881     break;
2882   }
2883   case Instruction::Select: {
2884     Code = bitc::FUNC_CODE_INST_VSELECT;
2885     pushValueAndType(I.getOperand(1), InstID, Vals);
2886     pushValue(I.getOperand(2), InstID, Vals);
2887     pushValueAndType(I.getOperand(0), InstID, Vals);
2888     uint64_t Flags = getOptimizationFlags(&I);
2889     if (Flags != 0)
2890       Vals.push_back(Flags);
2891     break;
2892   }
2893   case Instruction::ExtractElement:
2894     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
2895     pushValueAndType(I.getOperand(0), InstID, Vals);
2896     pushValueAndType(I.getOperand(1), InstID, Vals);
2897     break;
2898   case Instruction::InsertElement:
2899     Code = bitc::FUNC_CODE_INST_INSERTELT;
2900     pushValueAndType(I.getOperand(0), InstID, Vals);
2901     pushValue(I.getOperand(1), InstID, Vals);
2902     pushValueAndType(I.getOperand(2), InstID, Vals);
2903     break;
2904   case Instruction::ShuffleVector:
2905     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
2906     pushValueAndType(I.getOperand(0), InstID, Vals);
2907     pushValue(I.getOperand(1), InstID, Vals);
2908     pushValue(cast<ShuffleVectorInst>(I).getShuffleMaskForBitcode(), InstID,
2909               Vals);
2910     break;
2911   case Instruction::ICmp:
2912   case Instruction::FCmp: {
2913     // compare returning Int1Ty or vector of Int1Ty
2914     Code = bitc::FUNC_CODE_INST_CMP2;
2915     pushValueAndType(I.getOperand(0), InstID, Vals);
2916     pushValue(I.getOperand(1), InstID, Vals);
2917     Vals.push_back(cast<CmpInst>(I).getPredicate());
2918     uint64_t Flags = getOptimizationFlags(&I);
2919     if (Flags != 0)
2920       Vals.push_back(Flags);
2921     break;
2922   }
2923 
2924   case Instruction::Ret:
2925     {
2926       Code = bitc::FUNC_CODE_INST_RET;
2927       unsigned NumOperands = I.getNumOperands();
2928       if (NumOperands == 0)
2929         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
2930       else if (NumOperands == 1) {
2931         if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2932           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
2933       } else {
2934         for (unsigned i = 0, e = NumOperands; i != e; ++i)
2935           pushValueAndType(I.getOperand(i), InstID, Vals);
2936       }
2937     }
2938     break;
2939   case Instruction::Br:
2940     {
2941       Code = bitc::FUNC_CODE_INST_BR;
2942       const BranchInst &II = cast<BranchInst>(I);
2943       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
2944       if (II.isConditional()) {
2945         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
2946         pushValue(II.getCondition(), InstID, Vals);
2947       }
2948     }
2949     break;
2950   case Instruction::Switch:
2951     {
2952       Code = bitc::FUNC_CODE_INST_SWITCH;
2953       const SwitchInst &SI = cast<SwitchInst>(I);
2954       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
2955       pushValue(SI.getCondition(), InstID, Vals);
2956       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
2957       for (auto Case : SI.cases()) {
2958         Vals.push_back(VE.getValueID(Case.getCaseValue()));
2959         Vals.push_back(VE.getValueID(Case.getCaseSuccessor()));
2960       }
2961     }
2962     break;
2963   case Instruction::IndirectBr:
2964     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
2965     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2966     // Encode the address operand as relative, but not the basic blocks.
2967     pushValue(I.getOperand(0), InstID, Vals);
2968     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
2969       Vals.push_back(VE.getValueID(I.getOperand(i)));
2970     break;
2971 
2972   case Instruction::Invoke: {
2973     const InvokeInst *II = cast<InvokeInst>(&I);
2974     const Value *Callee = II->getCalledOperand();
2975     FunctionType *FTy = II->getFunctionType();
2976 
2977     if (II->hasOperandBundles())
2978       writeOperandBundles(*II, InstID);
2979 
2980     Code = bitc::FUNC_CODE_INST_INVOKE;
2981 
2982     Vals.push_back(VE.getAttributeListID(II->getAttributes()));
2983     Vals.push_back(II->getCallingConv() | 1 << 13);
2984     Vals.push_back(VE.getValueID(II->getNormalDest()));
2985     Vals.push_back(VE.getValueID(II->getUnwindDest()));
2986     Vals.push_back(VE.getTypeID(FTy));
2987     pushValueAndType(Callee, InstID, Vals);
2988 
2989     // Emit value #'s for the fixed parameters.
2990     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
2991       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
2992 
2993     // Emit type/value pairs for varargs params.
2994     if (FTy->isVarArg()) {
2995       for (unsigned i = FTy->getNumParams(), e = II->arg_size(); i != e; ++i)
2996         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
2997     }
2998     break;
2999   }
3000   case Instruction::Resume:
3001     Code = bitc::FUNC_CODE_INST_RESUME;
3002     pushValueAndType(I.getOperand(0), InstID, Vals);
3003     break;
3004   case Instruction::CleanupRet: {
3005     Code = bitc::FUNC_CODE_INST_CLEANUPRET;
3006     const auto &CRI = cast<CleanupReturnInst>(I);
3007     pushValue(CRI.getCleanupPad(), InstID, Vals);
3008     if (CRI.hasUnwindDest())
3009       Vals.push_back(VE.getValueID(CRI.getUnwindDest()));
3010     break;
3011   }
3012   case Instruction::CatchRet: {
3013     Code = bitc::FUNC_CODE_INST_CATCHRET;
3014     const auto &CRI = cast<CatchReturnInst>(I);
3015     pushValue(CRI.getCatchPad(), InstID, Vals);
3016     Vals.push_back(VE.getValueID(CRI.getSuccessor()));
3017     break;
3018   }
3019   case Instruction::CleanupPad:
3020   case Instruction::CatchPad: {
3021     const auto &FuncletPad = cast<FuncletPadInst>(I);
3022     Code = isa<CatchPadInst>(FuncletPad) ? bitc::FUNC_CODE_INST_CATCHPAD
3023                                          : bitc::FUNC_CODE_INST_CLEANUPPAD;
3024     pushValue(FuncletPad.getParentPad(), InstID, Vals);
3025 
3026     unsigned NumArgOperands = FuncletPad.arg_size();
3027     Vals.push_back(NumArgOperands);
3028     for (unsigned Op = 0; Op != NumArgOperands; ++Op)
3029       pushValueAndType(FuncletPad.getArgOperand(Op), InstID, Vals);
3030     break;
3031   }
3032   case Instruction::CatchSwitch: {
3033     Code = bitc::FUNC_CODE_INST_CATCHSWITCH;
3034     const auto &CatchSwitch = cast<CatchSwitchInst>(I);
3035 
3036     pushValue(CatchSwitch.getParentPad(), InstID, Vals);
3037 
3038     unsigned NumHandlers = CatchSwitch.getNumHandlers();
3039     Vals.push_back(NumHandlers);
3040     for (const BasicBlock *CatchPadBB : CatchSwitch.handlers())
3041       Vals.push_back(VE.getValueID(CatchPadBB));
3042 
3043     if (CatchSwitch.hasUnwindDest())
3044       Vals.push_back(VE.getValueID(CatchSwitch.getUnwindDest()));
3045     break;
3046   }
3047   case Instruction::CallBr: {
3048     const CallBrInst *CBI = cast<CallBrInst>(&I);
3049     const Value *Callee = CBI->getCalledOperand();
3050     FunctionType *FTy = CBI->getFunctionType();
3051 
3052     if (CBI->hasOperandBundles())
3053       writeOperandBundles(*CBI, InstID);
3054 
3055     Code = bitc::FUNC_CODE_INST_CALLBR;
3056 
3057     Vals.push_back(VE.getAttributeListID(CBI->getAttributes()));
3058 
3059     Vals.push_back(CBI->getCallingConv() << bitc::CALL_CCONV |
3060                    1 << bitc::CALL_EXPLICIT_TYPE);
3061 
3062     Vals.push_back(VE.getValueID(CBI->getDefaultDest()));
3063     Vals.push_back(CBI->getNumIndirectDests());
3064     for (unsigned i = 0, e = CBI->getNumIndirectDests(); i != e; ++i)
3065       Vals.push_back(VE.getValueID(CBI->getIndirectDest(i)));
3066 
3067     Vals.push_back(VE.getTypeID(FTy));
3068     pushValueAndType(Callee, InstID, Vals);
3069 
3070     // Emit value #'s for the fixed parameters.
3071     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
3072       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
3073 
3074     // Emit type/value pairs for varargs params.
3075     if (FTy->isVarArg()) {
3076       for (unsigned i = FTy->getNumParams(), e = CBI->arg_size(); i != e; ++i)
3077         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
3078     }
3079     break;
3080   }
3081   case Instruction::Unreachable:
3082     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
3083     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
3084     break;
3085 
3086   case Instruction::PHI: {
3087     const PHINode &PN = cast<PHINode>(I);
3088     Code = bitc::FUNC_CODE_INST_PHI;
3089     // With the newer instruction encoding, forward references could give
3090     // negative valued IDs.  This is most common for PHIs, so we use
3091     // signed VBRs.
3092     SmallVector<uint64_t, 128> Vals64;
3093     Vals64.push_back(VE.getTypeID(PN.getType()));
3094     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
3095       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64);
3096       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
3097     }
3098 
3099     uint64_t Flags = getOptimizationFlags(&I);
3100     if (Flags != 0)
3101       Vals64.push_back(Flags);
3102 
3103     // Emit a Vals64 vector and exit.
3104     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
3105     Vals64.clear();
3106     return;
3107   }
3108 
3109   case Instruction::LandingPad: {
3110     const LandingPadInst &LP = cast<LandingPadInst>(I);
3111     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
3112     Vals.push_back(VE.getTypeID(LP.getType()));
3113     Vals.push_back(LP.isCleanup());
3114     Vals.push_back(LP.getNumClauses());
3115     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
3116       if (LP.isCatch(I))
3117         Vals.push_back(LandingPadInst::Catch);
3118       else
3119         Vals.push_back(LandingPadInst::Filter);
3120       pushValueAndType(LP.getClause(I), InstID, Vals);
3121     }
3122     break;
3123   }
3124 
3125   case Instruction::Alloca: {
3126     Code = bitc::FUNC_CODE_INST_ALLOCA;
3127     const AllocaInst &AI = cast<AllocaInst>(I);
3128     Vals.push_back(VE.getTypeID(AI.getAllocatedType()));
3129     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
3130     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
3131     using APV = AllocaPackedValues;
3132     unsigned Record = 0;
3133     unsigned EncodedAlign = getEncodedAlign(AI.getAlign());
3134     Bitfield::set<APV::AlignLower>(
3135         Record, EncodedAlign & ((1 << APV::AlignLower::Bits) - 1));
3136     Bitfield::set<APV::AlignUpper>(Record,
3137                                    EncodedAlign >> APV::AlignLower::Bits);
3138     Bitfield::set<APV::UsedWithInAlloca>(Record, AI.isUsedWithInAlloca());
3139     Bitfield::set<APV::ExplicitType>(Record, true);
3140     Bitfield::set<APV::SwiftError>(Record, AI.isSwiftError());
3141     Vals.push_back(Record);
3142 
3143     unsigned AS = AI.getAddressSpace();
3144     if (AS != M.getDataLayout().getAllocaAddrSpace())
3145       Vals.push_back(AS);
3146     break;
3147   }
3148 
3149   case Instruction::Load:
3150     if (cast<LoadInst>(I).isAtomic()) {
3151       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
3152       pushValueAndType(I.getOperand(0), InstID, Vals);
3153     } else {
3154       Code = bitc::FUNC_CODE_INST_LOAD;
3155       if (!pushValueAndType(I.getOperand(0), InstID, Vals)) // ptr
3156         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
3157     }
3158     Vals.push_back(VE.getTypeID(I.getType()));
3159     Vals.push_back(getEncodedAlign(cast<LoadInst>(I).getAlign()));
3160     Vals.push_back(cast<LoadInst>(I).isVolatile());
3161     if (cast<LoadInst>(I).isAtomic()) {
3162       Vals.push_back(getEncodedOrdering(cast<LoadInst>(I).getOrdering()));
3163       Vals.push_back(getEncodedSyncScopeID(cast<LoadInst>(I).getSyncScopeID()));
3164     }
3165     break;
3166   case Instruction::Store:
3167     if (cast<StoreInst>(I).isAtomic())
3168       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
3169     else
3170       Code = bitc::FUNC_CODE_INST_STORE;
3171     pushValueAndType(I.getOperand(1), InstID, Vals); // ptrty + ptr
3172     pushValueAndType(I.getOperand(0), InstID, Vals); // valty + val
3173     Vals.push_back(getEncodedAlign(cast<StoreInst>(I).getAlign()));
3174     Vals.push_back(cast<StoreInst>(I).isVolatile());
3175     if (cast<StoreInst>(I).isAtomic()) {
3176       Vals.push_back(getEncodedOrdering(cast<StoreInst>(I).getOrdering()));
3177       Vals.push_back(
3178           getEncodedSyncScopeID(cast<StoreInst>(I).getSyncScopeID()));
3179     }
3180     break;
3181   case Instruction::AtomicCmpXchg:
3182     Code = bitc::FUNC_CODE_INST_CMPXCHG;
3183     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
3184     pushValueAndType(I.getOperand(1), InstID, Vals); // cmp.
3185     pushValue(I.getOperand(2), InstID, Vals);        // newval.
3186     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
3187     Vals.push_back(
3188         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
3189     Vals.push_back(
3190         getEncodedSyncScopeID(cast<AtomicCmpXchgInst>(I).getSyncScopeID()));
3191     Vals.push_back(
3192         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
3193     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
3194     Vals.push_back(getEncodedAlign(cast<AtomicCmpXchgInst>(I).getAlign()));
3195     break;
3196   case Instruction::AtomicRMW:
3197     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
3198     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
3199     pushValueAndType(I.getOperand(1), InstID, Vals); // valty + val
3200     Vals.push_back(
3201         getEncodedRMWOperation(cast<AtomicRMWInst>(I).getOperation()));
3202     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
3203     Vals.push_back(getEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
3204     Vals.push_back(
3205         getEncodedSyncScopeID(cast<AtomicRMWInst>(I).getSyncScopeID()));
3206     Vals.push_back(getEncodedAlign(cast<AtomicRMWInst>(I).getAlign()));
3207     break;
3208   case Instruction::Fence:
3209     Code = bitc::FUNC_CODE_INST_FENCE;
3210     Vals.push_back(getEncodedOrdering(cast<FenceInst>(I).getOrdering()));
3211     Vals.push_back(getEncodedSyncScopeID(cast<FenceInst>(I).getSyncScopeID()));
3212     break;
3213   case Instruction::Call: {
3214     const CallInst &CI = cast<CallInst>(I);
3215     FunctionType *FTy = CI.getFunctionType();
3216 
3217     if (CI.hasOperandBundles())
3218       writeOperandBundles(CI, InstID);
3219 
3220     Code = bitc::FUNC_CODE_INST_CALL;
3221 
3222     Vals.push_back(VE.getAttributeListID(CI.getAttributes()));
3223 
3224     unsigned Flags = getOptimizationFlags(&I);
3225     Vals.push_back(CI.getCallingConv() << bitc::CALL_CCONV |
3226                    unsigned(CI.isTailCall()) << bitc::CALL_TAIL |
3227                    unsigned(CI.isMustTailCall()) << bitc::CALL_MUSTTAIL |
3228                    1 << bitc::CALL_EXPLICIT_TYPE |
3229                    unsigned(CI.isNoTailCall()) << bitc::CALL_NOTAIL |
3230                    unsigned(Flags != 0) << bitc::CALL_FMF);
3231     if (Flags != 0)
3232       Vals.push_back(Flags);
3233 
3234     Vals.push_back(VE.getTypeID(FTy));
3235     pushValueAndType(CI.getCalledOperand(), InstID, Vals); // Callee
3236 
3237     // Emit value #'s for the fixed parameters.
3238     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
3239       // Check for labels (can happen with asm labels).
3240       if (FTy->getParamType(i)->isLabelTy())
3241         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
3242       else
3243         pushValue(CI.getArgOperand(i), InstID, Vals); // fixed param.
3244     }
3245 
3246     // Emit type/value pairs for varargs params.
3247     if (FTy->isVarArg()) {
3248       for (unsigned i = FTy->getNumParams(), e = CI.arg_size(); i != e; ++i)
3249         pushValueAndType(CI.getArgOperand(i), InstID, Vals); // varargs
3250     }
3251     break;
3252   }
3253   case Instruction::VAArg:
3254     Code = bitc::FUNC_CODE_INST_VAARG;
3255     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
3256     pushValue(I.getOperand(0), InstID, Vals);                   // valist.
3257     Vals.push_back(VE.getTypeID(I.getType())); // restype.
3258     break;
3259   case Instruction::Freeze:
3260     Code = bitc::FUNC_CODE_INST_FREEZE;
3261     pushValueAndType(I.getOperand(0), InstID, Vals);
3262     break;
3263   }
3264 
3265   Stream.EmitRecord(Code, Vals, AbbrevToUse);
3266   Vals.clear();
3267 }
3268 
3269 /// Write a GlobalValue VST to the module. The purpose of this data structure is
3270 /// to allow clients to efficiently find the function body.
3271 void ModuleBitcodeWriter::writeGlobalValueSymbolTable(
3272   DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3273   // Get the offset of the VST we are writing, and backpatch it into
3274   // the VST forward declaration record.
3275   uint64_t VSTOffset = Stream.GetCurrentBitNo();
3276   // The BitcodeStartBit was the stream offset of the identification block.
3277   VSTOffset -= bitcodeStartBit();
3278   assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
3279   // Note that we add 1 here because the offset is relative to one word
3280   // before the start of the identification block, which was historically
3281   // always the start of the regular bitcode header.
3282   Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32 + 1);
3283 
3284   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3285 
3286   auto Abbv = std::make_shared<BitCodeAbbrev>();
3287   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
3288   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
3289   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
3290   unsigned FnEntryAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3291 
3292   for (const Function &F : M) {
3293     uint64_t Record[2];
3294 
3295     if (F.isDeclaration())
3296       continue;
3297 
3298     Record[0] = VE.getValueID(&F);
3299 
3300     // Save the word offset of the function (from the start of the
3301     // actual bitcode written to the stream).
3302     uint64_t BitcodeIndex = FunctionToBitcodeIndex[&F] - bitcodeStartBit();
3303     assert((BitcodeIndex & 31) == 0 && "function block not 32-bit aligned");
3304     // Note that we add 1 here because the offset is relative to one word
3305     // before the start of the identification block, which was historically
3306     // always the start of the regular bitcode header.
3307     Record[1] = BitcodeIndex / 32 + 1;
3308 
3309     Stream.EmitRecord(bitc::VST_CODE_FNENTRY, Record, FnEntryAbbrev);
3310   }
3311 
3312   Stream.ExitBlock();
3313 }
3314 
3315 /// Emit names for arguments, instructions and basic blocks in a function.
3316 void ModuleBitcodeWriter::writeFunctionLevelValueSymbolTable(
3317     const ValueSymbolTable &VST) {
3318   if (VST.empty())
3319     return;
3320 
3321   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3322 
3323   // FIXME: Set up the abbrev, we know how many values there are!
3324   // FIXME: We know if the type names can use 7-bit ascii.
3325   SmallVector<uint64_t, 64> NameVals;
3326 
3327   for (const ValueName &Name : VST) {
3328     // Figure out the encoding to use for the name.
3329     StringEncoding Bits = getStringEncoding(Name.getKey());
3330 
3331     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
3332     NameVals.push_back(VE.getValueID(Name.getValue()));
3333 
3334     // VST_CODE_ENTRY:   [valueid, namechar x N]
3335     // VST_CODE_BBENTRY: [bbid, namechar x N]
3336     unsigned Code;
3337     if (isa<BasicBlock>(Name.getValue())) {
3338       Code = bitc::VST_CODE_BBENTRY;
3339       if (Bits == SE_Char6)
3340         AbbrevToUse = VST_BBENTRY_6_ABBREV;
3341     } else {
3342       Code = bitc::VST_CODE_ENTRY;
3343       if (Bits == SE_Char6)
3344         AbbrevToUse = VST_ENTRY_6_ABBREV;
3345       else if (Bits == SE_Fixed7)
3346         AbbrevToUse = VST_ENTRY_7_ABBREV;
3347     }
3348 
3349     for (const auto P : Name.getKey())
3350       NameVals.push_back((unsigned char)P);
3351 
3352     // Emit the finished record.
3353     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
3354     NameVals.clear();
3355   }
3356 
3357   Stream.ExitBlock();
3358 }
3359 
3360 void ModuleBitcodeWriter::writeUseList(UseListOrder &&Order) {
3361   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
3362   unsigned Code;
3363   if (isa<BasicBlock>(Order.V))
3364     Code = bitc::USELIST_CODE_BB;
3365   else
3366     Code = bitc::USELIST_CODE_DEFAULT;
3367 
3368   SmallVector<uint64_t, 64> Record(Order.Shuffle.begin(), Order.Shuffle.end());
3369   Record.push_back(VE.getValueID(Order.V));
3370   Stream.EmitRecord(Code, Record);
3371 }
3372 
3373 void ModuleBitcodeWriter::writeUseListBlock(const Function *F) {
3374   assert(VE.shouldPreserveUseListOrder() &&
3375          "Expected to be preserving use-list order");
3376 
3377   auto hasMore = [&]() {
3378     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
3379   };
3380   if (!hasMore())
3381     // Nothing to do.
3382     return;
3383 
3384   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
3385   while (hasMore()) {
3386     writeUseList(std::move(VE.UseListOrders.back()));
3387     VE.UseListOrders.pop_back();
3388   }
3389   Stream.ExitBlock();
3390 }
3391 
3392 /// Emit a function body to the module stream.
3393 void ModuleBitcodeWriter::writeFunction(
3394     const Function &F,
3395     DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3396   // Save the bitcode index of the start of this function block for recording
3397   // in the VST.
3398   FunctionToBitcodeIndex[&F] = Stream.GetCurrentBitNo();
3399 
3400   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
3401   VE.incorporateFunction(F);
3402 
3403   SmallVector<unsigned, 64> Vals;
3404 
3405   // Emit the number of basic blocks, so the reader can create them ahead of
3406   // time.
3407   Vals.push_back(VE.getBasicBlocks().size());
3408   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
3409   Vals.clear();
3410 
3411   // If there are function-local constants, emit them now.
3412   unsigned CstStart, CstEnd;
3413   VE.getFunctionConstantRange(CstStart, CstEnd);
3414   writeConstants(CstStart, CstEnd, false);
3415 
3416   // If there is function-local metadata, emit it now.
3417   writeFunctionMetadata(F);
3418 
3419   // Keep a running idea of what the instruction ID is.
3420   unsigned InstID = CstEnd;
3421 
3422   bool NeedsMetadataAttachment = F.hasMetadata();
3423 
3424   DILocation *LastDL = nullptr;
3425   SmallSetVector<Function *, 4> BlockAddressUsers;
3426 
3427   // Finally, emit all the instructions, in order.
3428   for (const BasicBlock &BB : F) {
3429     for (const Instruction &I : BB) {
3430       writeInstruction(I, InstID, Vals);
3431 
3432       if (!I.getType()->isVoidTy())
3433         ++InstID;
3434 
3435       // If the instruction has metadata, write a metadata attachment later.
3436       NeedsMetadataAttachment |= I.hasMetadataOtherThanDebugLoc();
3437 
3438       // If the instruction has a debug location, emit it.
3439       DILocation *DL = I.getDebugLoc();
3440       if (!DL)
3441         continue;
3442 
3443       if (DL == LastDL) {
3444         // Just repeat the same debug loc as last time.
3445         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
3446         continue;
3447       }
3448 
3449       Vals.push_back(DL->getLine());
3450       Vals.push_back(DL->getColumn());
3451       Vals.push_back(VE.getMetadataOrNullID(DL->getScope()));
3452       Vals.push_back(VE.getMetadataOrNullID(DL->getInlinedAt()));
3453       Vals.push_back(DL->isImplicitCode());
3454       Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
3455       Vals.clear();
3456 
3457       LastDL = DL;
3458     }
3459 
3460     if (BlockAddress *BA = BlockAddress::lookup(&BB)) {
3461       SmallVector<Value *> Worklist{BA};
3462       SmallPtrSet<Value *, 8> Visited{BA};
3463       while (!Worklist.empty()) {
3464         Value *V = Worklist.pop_back_val();
3465         for (User *U : V->users()) {
3466           if (auto *I = dyn_cast<Instruction>(U)) {
3467             Function *P = I->getFunction();
3468             if (P != &F)
3469               BlockAddressUsers.insert(P);
3470           } else if (isa<Constant>(U) && !isa<GlobalValue>(U) &&
3471                      Visited.insert(U).second)
3472             Worklist.push_back(U);
3473         }
3474       }
3475     }
3476   }
3477 
3478   if (!BlockAddressUsers.empty()) {
3479     Vals.resize(BlockAddressUsers.size());
3480     for (auto I : llvm::enumerate(BlockAddressUsers))
3481       Vals[I.index()] = VE.getValueID(I.value());
3482     Stream.EmitRecord(bitc::FUNC_CODE_BLOCKADDR_USERS, Vals);
3483     Vals.clear();
3484   }
3485 
3486   // Emit names for all the instructions etc.
3487   if (auto *Symtab = F.getValueSymbolTable())
3488     writeFunctionLevelValueSymbolTable(*Symtab);
3489 
3490   if (NeedsMetadataAttachment)
3491     writeFunctionMetadataAttachment(F);
3492   if (VE.shouldPreserveUseListOrder())
3493     writeUseListBlock(&F);
3494   VE.purgeFunction();
3495   Stream.ExitBlock();
3496 }
3497 
3498 // Emit blockinfo, which defines the standard abbreviations etc.
3499 void ModuleBitcodeWriter::writeBlockInfo() {
3500   // We only want to emit block info records for blocks that have multiple
3501   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
3502   // Other blocks can define their abbrevs inline.
3503   Stream.EnterBlockInfoBlock();
3504 
3505   { // 8-bit fixed-width VST_CODE_ENTRY/VST_CODE_BBENTRY strings.
3506     auto Abbv = std::make_shared<BitCodeAbbrev>();
3507     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
3508     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3509     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3510     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3511     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3512         VST_ENTRY_8_ABBREV)
3513       llvm_unreachable("Unexpected abbrev ordering!");
3514   }
3515 
3516   { // 7-bit fixed width VST_CODE_ENTRY strings.
3517     auto Abbv = std::make_shared<BitCodeAbbrev>();
3518     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3519     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3520     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3521     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3522     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3523         VST_ENTRY_7_ABBREV)
3524       llvm_unreachable("Unexpected abbrev ordering!");
3525   }
3526   { // 6-bit char6 VST_CODE_ENTRY strings.
3527     auto Abbv = std::make_shared<BitCodeAbbrev>();
3528     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3529     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3530     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3531     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3532     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3533         VST_ENTRY_6_ABBREV)
3534       llvm_unreachable("Unexpected abbrev ordering!");
3535   }
3536   { // 6-bit char6 VST_CODE_BBENTRY strings.
3537     auto Abbv = std::make_shared<BitCodeAbbrev>();
3538     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
3539     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3540     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3541     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3542     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3543         VST_BBENTRY_6_ABBREV)
3544       llvm_unreachable("Unexpected abbrev ordering!");
3545   }
3546 
3547   { // SETTYPE abbrev for CONSTANTS_BLOCK.
3548     auto Abbv = std::make_shared<BitCodeAbbrev>();
3549     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
3550     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
3551                               VE.computeBitsRequiredForTypeIndicies()));
3552     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3553         CONSTANTS_SETTYPE_ABBREV)
3554       llvm_unreachable("Unexpected abbrev ordering!");
3555   }
3556 
3557   { // INTEGER abbrev for CONSTANTS_BLOCK.
3558     auto Abbv = std::make_shared<BitCodeAbbrev>();
3559     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
3560     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3561     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3562         CONSTANTS_INTEGER_ABBREV)
3563       llvm_unreachable("Unexpected abbrev ordering!");
3564   }
3565 
3566   { // CE_CAST abbrev for CONSTANTS_BLOCK.
3567     auto Abbv = std::make_shared<BitCodeAbbrev>();
3568     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
3569     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
3570     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
3571                               VE.computeBitsRequiredForTypeIndicies()));
3572     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
3573 
3574     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3575         CONSTANTS_CE_CAST_Abbrev)
3576       llvm_unreachable("Unexpected abbrev ordering!");
3577   }
3578   { // NULL abbrev for CONSTANTS_BLOCK.
3579     auto Abbv = std::make_shared<BitCodeAbbrev>();
3580     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
3581     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3582         CONSTANTS_NULL_Abbrev)
3583       llvm_unreachable("Unexpected abbrev ordering!");
3584   }
3585 
3586   // FIXME: This should only use space for first class types!
3587 
3588   { // INST_LOAD abbrev for FUNCTION_BLOCK.
3589     auto Abbv = std::make_shared<BitCodeAbbrev>();
3590     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
3591     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
3592     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
3593                               VE.computeBitsRequiredForTypeIndicies()));
3594     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
3595     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
3596     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3597         FUNCTION_INST_LOAD_ABBREV)
3598       llvm_unreachable("Unexpected abbrev ordering!");
3599   }
3600   { // INST_UNOP abbrev for FUNCTION_BLOCK.
3601     auto Abbv = std::make_shared<BitCodeAbbrev>();
3602     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3603     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3604     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3605     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3606         FUNCTION_INST_UNOP_ABBREV)
3607       llvm_unreachable("Unexpected abbrev ordering!");
3608   }
3609   { // INST_UNOP_FLAGS abbrev for FUNCTION_BLOCK.
3610     auto Abbv = std::make_shared<BitCodeAbbrev>();
3611     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3612     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3613     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3614     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3615     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3616         FUNCTION_INST_UNOP_FLAGS_ABBREV)
3617       llvm_unreachable("Unexpected abbrev ordering!");
3618   }
3619   { // INST_BINOP abbrev for FUNCTION_BLOCK.
3620     auto Abbv = std::make_shared<BitCodeAbbrev>();
3621     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3622     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3623     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3624     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3625     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3626         FUNCTION_INST_BINOP_ABBREV)
3627       llvm_unreachable("Unexpected abbrev ordering!");
3628   }
3629   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
3630     auto Abbv = std::make_shared<BitCodeAbbrev>();
3631     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3632     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3633     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3634     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3635     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3636     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3637         FUNCTION_INST_BINOP_FLAGS_ABBREV)
3638       llvm_unreachable("Unexpected abbrev ordering!");
3639   }
3640   { // INST_CAST abbrev for FUNCTION_BLOCK.
3641     auto Abbv = std::make_shared<BitCodeAbbrev>();
3642     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
3643     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
3644     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
3645                               VE.computeBitsRequiredForTypeIndicies()));
3646     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
3647     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3648         FUNCTION_INST_CAST_ABBREV)
3649       llvm_unreachable("Unexpected abbrev ordering!");
3650   }
3651 
3652   { // INST_RET abbrev for FUNCTION_BLOCK.
3653     auto Abbv = std::make_shared<BitCodeAbbrev>();
3654     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3655     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3656         FUNCTION_INST_RET_VOID_ABBREV)
3657       llvm_unreachable("Unexpected abbrev ordering!");
3658   }
3659   { // INST_RET abbrev for FUNCTION_BLOCK.
3660     auto Abbv = std::make_shared<BitCodeAbbrev>();
3661     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3662     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
3663     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3664         FUNCTION_INST_RET_VAL_ABBREV)
3665       llvm_unreachable("Unexpected abbrev ordering!");
3666   }
3667   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
3668     auto Abbv = std::make_shared<BitCodeAbbrev>();
3669     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
3670     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3671         FUNCTION_INST_UNREACHABLE_ABBREV)
3672       llvm_unreachable("Unexpected abbrev ordering!");
3673   }
3674   {
3675     auto Abbv = std::make_shared<BitCodeAbbrev>();
3676     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_GEP));
3677     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
3678     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, // dest ty
3679                               Log2_32_Ceil(VE.getTypes().size() + 1)));
3680     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3681     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
3682     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3683         FUNCTION_INST_GEP_ABBREV)
3684       llvm_unreachable("Unexpected abbrev ordering!");
3685   }
3686 
3687   Stream.ExitBlock();
3688 }
3689 
3690 /// Write the module path strings, currently only used when generating
3691 /// a combined index file.
3692 void IndexBitcodeWriter::writeModStrings() {
3693   Stream.EnterSubblock(bitc::MODULE_STRTAB_BLOCK_ID, 3);
3694 
3695   // TODO: See which abbrev sizes we actually need to emit
3696 
3697   // 8-bit fixed-width MST_ENTRY strings.
3698   auto Abbv = std::make_shared<BitCodeAbbrev>();
3699   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3700   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3701   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3702   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3703   unsigned Abbrev8Bit = Stream.EmitAbbrev(std::move(Abbv));
3704 
3705   // 7-bit fixed width MST_ENTRY strings.
3706   Abbv = std::make_shared<BitCodeAbbrev>();
3707   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3708   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3709   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3710   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3711   unsigned Abbrev7Bit = Stream.EmitAbbrev(std::move(Abbv));
3712 
3713   // 6-bit char6 MST_ENTRY strings.
3714   Abbv = std::make_shared<BitCodeAbbrev>();
3715   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3716   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3717   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3718   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3719   unsigned Abbrev6Bit = Stream.EmitAbbrev(std::move(Abbv));
3720 
3721   // Module Hash, 160 bits SHA1. Optionally, emitted after each MST_CODE_ENTRY.
3722   Abbv = std::make_shared<BitCodeAbbrev>();
3723   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_HASH));
3724   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3725   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3726   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3727   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3728   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3729   unsigned AbbrevHash = Stream.EmitAbbrev(std::move(Abbv));
3730 
3731   SmallVector<unsigned, 64> Vals;
3732   forEachModule([&](const StringMapEntry<ModuleHash> &MPSE) {
3733     StringRef Key = MPSE.getKey();
3734     const auto &Hash = MPSE.getValue();
3735     StringEncoding Bits = getStringEncoding(Key);
3736     unsigned AbbrevToUse = Abbrev8Bit;
3737     if (Bits == SE_Char6)
3738       AbbrevToUse = Abbrev6Bit;
3739     else if (Bits == SE_Fixed7)
3740       AbbrevToUse = Abbrev7Bit;
3741 
3742     auto ModuleId = ModuleIdMap.size();
3743     ModuleIdMap[Key] = ModuleId;
3744     Vals.push_back(ModuleId);
3745     Vals.append(Key.begin(), Key.end());
3746 
3747     // Emit the finished record.
3748     Stream.EmitRecord(bitc::MST_CODE_ENTRY, Vals, AbbrevToUse);
3749 
3750     // Emit an optional hash for the module now
3751     if (llvm::any_of(Hash, [](uint32_t H) { return H; })) {
3752       Vals.assign(Hash.begin(), Hash.end());
3753       // Emit the hash record.
3754       Stream.EmitRecord(bitc::MST_CODE_HASH, Vals, AbbrevHash);
3755     }
3756 
3757     Vals.clear();
3758   });
3759   Stream.ExitBlock();
3760 }
3761 
3762 /// Write the function type metadata related records that need to appear before
3763 /// a function summary entry (whether per-module or combined).
3764 template <typename Fn>
3765 static void writeFunctionTypeMetadataRecords(BitstreamWriter &Stream,
3766                                              FunctionSummary *FS,
3767                                              Fn GetValueID) {
3768   if (!FS->type_tests().empty())
3769     Stream.EmitRecord(bitc::FS_TYPE_TESTS, FS->type_tests());
3770 
3771   SmallVector<uint64_t, 64> Record;
3772 
3773   auto WriteVFuncIdVec = [&](uint64_t Ty,
3774                              ArrayRef<FunctionSummary::VFuncId> VFs) {
3775     if (VFs.empty())
3776       return;
3777     Record.clear();
3778     for (auto &VF : VFs) {
3779       Record.push_back(VF.GUID);
3780       Record.push_back(VF.Offset);
3781     }
3782     Stream.EmitRecord(Ty, Record);
3783   };
3784 
3785   WriteVFuncIdVec(bitc::FS_TYPE_TEST_ASSUME_VCALLS,
3786                   FS->type_test_assume_vcalls());
3787   WriteVFuncIdVec(bitc::FS_TYPE_CHECKED_LOAD_VCALLS,
3788                   FS->type_checked_load_vcalls());
3789 
3790   auto WriteConstVCallVec = [&](uint64_t Ty,
3791                                 ArrayRef<FunctionSummary::ConstVCall> VCs) {
3792     for (auto &VC : VCs) {
3793       Record.clear();
3794       Record.push_back(VC.VFunc.GUID);
3795       Record.push_back(VC.VFunc.Offset);
3796       llvm::append_range(Record, VC.Args);
3797       Stream.EmitRecord(Ty, Record);
3798     }
3799   };
3800 
3801   WriteConstVCallVec(bitc::FS_TYPE_TEST_ASSUME_CONST_VCALL,
3802                      FS->type_test_assume_const_vcalls());
3803   WriteConstVCallVec(bitc::FS_TYPE_CHECKED_LOAD_CONST_VCALL,
3804                      FS->type_checked_load_const_vcalls());
3805 
3806   auto WriteRange = [&](ConstantRange Range) {
3807     Range = Range.sextOrTrunc(FunctionSummary::ParamAccess::RangeWidth);
3808     assert(Range.getLower().getNumWords() == 1);
3809     assert(Range.getUpper().getNumWords() == 1);
3810     emitSignedInt64(Record, *Range.getLower().getRawData());
3811     emitSignedInt64(Record, *Range.getUpper().getRawData());
3812   };
3813 
3814   if (!FS->paramAccesses().empty()) {
3815     Record.clear();
3816     for (auto &Arg : FS->paramAccesses()) {
3817       size_t UndoSize = Record.size();
3818       Record.push_back(Arg.ParamNo);
3819       WriteRange(Arg.Use);
3820       Record.push_back(Arg.Calls.size());
3821       for (auto &Call : Arg.Calls) {
3822         Record.push_back(Call.ParamNo);
3823         std::optional<unsigned> ValueID = GetValueID(Call.Callee);
3824         if (!ValueID) {
3825           // If ValueID is unknown we can't drop just this call, we must drop
3826           // entire parameter.
3827           Record.resize(UndoSize);
3828           break;
3829         }
3830         Record.push_back(*ValueID);
3831         WriteRange(Call.Offsets);
3832       }
3833     }
3834     if (!Record.empty())
3835       Stream.EmitRecord(bitc::FS_PARAM_ACCESS, Record);
3836   }
3837 }
3838 
3839 /// Collect type IDs from type tests used by function.
3840 static void
3841 getReferencedTypeIds(FunctionSummary *FS,
3842                      std::set<GlobalValue::GUID> &ReferencedTypeIds) {
3843   if (!FS->type_tests().empty())
3844     for (auto &TT : FS->type_tests())
3845       ReferencedTypeIds.insert(TT);
3846 
3847   auto GetReferencedTypesFromVFuncIdVec =
3848       [&](ArrayRef<FunctionSummary::VFuncId> VFs) {
3849         for (auto &VF : VFs)
3850           ReferencedTypeIds.insert(VF.GUID);
3851       };
3852 
3853   GetReferencedTypesFromVFuncIdVec(FS->type_test_assume_vcalls());
3854   GetReferencedTypesFromVFuncIdVec(FS->type_checked_load_vcalls());
3855 
3856   auto GetReferencedTypesFromConstVCallVec =
3857       [&](ArrayRef<FunctionSummary::ConstVCall> VCs) {
3858         for (auto &VC : VCs)
3859           ReferencedTypeIds.insert(VC.VFunc.GUID);
3860       };
3861 
3862   GetReferencedTypesFromConstVCallVec(FS->type_test_assume_const_vcalls());
3863   GetReferencedTypesFromConstVCallVec(FS->type_checked_load_const_vcalls());
3864 }
3865 
3866 static void writeWholeProgramDevirtResolutionByArg(
3867     SmallVector<uint64_t, 64> &NameVals, const std::vector<uint64_t> &args,
3868     const WholeProgramDevirtResolution::ByArg &ByArg) {
3869   NameVals.push_back(args.size());
3870   llvm::append_range(NameVals, args);
3871 
3872   NameVals.push_back(ByArg.TheKind);
3873   NameVals.push_back(ByArg.Info);
3874   NameVals.push_back(ByArg.Byte);
3875   NameVals.push_back(ByArg.Bit);
3876 }
3877 
3878 static void writeWholeProgramDevirtResolution(
3879     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3880     uint64_t Id, const WholeProgramDevirtResolution &Wpd) {
3881   NameVals.push_back(Id);
3882 
3883   NameVals.push_back(Wpd.TheKind);
3884   NameVals.push_back(StrtabBuilder.add(Wpd.SingleImplName));
3885   NameVals.push_back(Wpd.SingleImplName.size());
3886 
3887   NameVals.push_back(Wpd.ResByArg.size());
3888   for (auto &A : Wpd.ResByArg)
3889     writeWholeProgramDevirtResolutionByArg(NameVals, A.first, A.second);
3890 }
3891 
3892 static void writeTypeIdSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
3893                                      StringTableBuilder &StrtabBuilder,
3894                                      const std::string &Id,
3895                                      const TypeIdSummary &Summary) {
3896   NameVals.push_back(StrtabBuilder.add(Id));
3897   NameVals.push_back(Id.size());
3898 
3899   NameVals.push_back(Summary.TTRes.TheKind);
3900   NameVals.push_back(Summary.TTRes.SizeM1BitWidth);
3901   NameVals.push_back(Summary.TTRes.AlignLog2);
3902   NameVals.push_back(Summary.TTRes.SizeM1);
3903   NameVals.push_back(Summary.TTRes.BitMask);
3904   NameVals.push_back(Summary.TTRes.InlineBits);
3905 
3906   for (auto &W : Summary.WPDRes)
3907     writeWholeProgramDevirtResolution(NameVals, StrtabBuilder, W.first,
3908                                       W.second);
3909 }
3910 
3911 static void writeTypeIdCompatibleVtableSummaryRecord(
3912     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3913     const std::string &Id, const TypeIdCompatibleVtableInfo &Summary,
3914     ValueEnumerator &VE) {
3915   NameVals.push_back(StrtabBuilder.add(Id));
3916   NameVals.push_back(Id.size());
3917 
3918   for (auto &P : Summary) {
3919     NameVals.push_back(P.AddressPointOffset);
3920     NameVals.push_back(VE.getValueID(P.VTableVI.getValue()));
3921   }
3922 }
3923 
3924 static void writeFunctionHeapProfileRecords(
3925     BitstreamWriter &Stream, FunctionSummary *FS, unsigned CallsiteAbbrev,
3926     unsigned AllocAbbrev, bool PerModule,
3927     std::function<unsigned(const ValueInfo &VI)> GetValueID,
3928     std::function<unsigned(unsigned)> GetStackIndex) {
3929   SmallVector<uint64_t> Record;
3930 
3931   for (auto &CI : FS->callsites()) {
3932     Record.clear();
3933     // Per module callsite clones should always have a single entry of
3934     // value 0.
3935     assert(!PerModule || (CI.Clones.size() == 1 && CI.Clones[0] == 0));
3936     Record.push_back(GetValueID(CI.Callee));
3937     if (!PerModule) {
3938       Record.push_back(CI.StackIdIndices.size());
3939       Record.push_back(CI.Clones.size());
3940     }
3941     for (auto Id : CI.StackIdIndices)
3942       Record.push_back(GetStackIndex(Id));
3943     if (!PerModule) {
3944       for (auto V : CI.Clones)
3945         Record.push_back(V);
3946     }
3947     Stream.EmitRecord(PerModule ? bitc::FS_PERMODULE_CALLSITE_INFO
3948                                 : bitc::FS_COMBINED_CALLSITE_INFO,
3949                       Record, CallsiteAbbrev);
3950   }
3951 
3952   for (auto &AI : FS->allocs()) {
3953     Record.clear();
3954     // Per module alloc versions should always have a single entry of
3955     // value 0.
3956     assert(!PerModule || (AI.Versions.size() == 1 && AI.Versions[0] == 0));
3957     if (!PerModule) {
3958       Record.push_back(AI.MIBs.size());
3959       Record.push_back(AI.Versions.size());
3960     }
3961     for (auto &MIB : AI.MIBs) {
3962       Record.push_back((uint8_t)MIB.AllocType);
3963       Record.push_back(MIB.StackIdIndices.size());
3964       for (auto Id : MIB.StackIdIndices)
3965         Record.push_back(GetStackIndex(Id));
3966     }
3967     if (!PerModule) {
3968       for (auto V : AI.Versions)
3969         Record.push_back(V);
3970     }
3971     Stream.EmitRecord(PerModule ? bitc::FS_PERMODULE_ALLOC_INFO
3972                                 : bitc::FS_COMBINED_ALLOC_INFO,
3973                       Record, AllocAbbrev);
3974   }
3975 }
3976 
3977 // Helper to emit a single function summary record.
3978 void ModuleBitcodeWriterBase::writePerModuleFunctionSummaryRecord(
3979     SmallVector<uint64_t, 64> &NameVals, GlobalValueSummary *Summary,
3980     unsigned ValueID, unsigned FSCallsAbbrev, unsigned FSCallsProfileAbbrev,
3981     unsigned CallsiteAbbrev, unsigned AllocAbbrev, const Function &F) {
3982   NameVals.push_back(ValueID);
3983 
3984   FunctionSummary *FS = cast<FunctionSummary>(Summary);
3985 
3986   writeFunctionTypeMetadataRecords(
3987       Stream, FS, [&](const ValueInfo &VI) -> std::optional<unsigned> {
3988         return {VE.getValueID(VI.getValue())};
3989       });
3990 
3991   writeFunctionHeapProfileRecords(
3992       Stream, FS, CallsiteAbbrev, AllocAbbrev,
3993       /*PerModule*/ true,
3994       /*GetValueId*/ [&](const ValueInfo &VI) { return getValueId(VI); },
3995       /*GetStackIndex*/ [&](unsigned I) { return I; });
3996 
3997   auto SpecialRefCnts = FS->specialRefCounts();
3998   NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
3999   NameVals.push_back(FS->instCount());
4000   NameVals.push_back(getEncodedFFlags(FS->fflags()));
4001   NameVals.push_back(FS->refs().size());
4002   NameVals.push_back(SpecialRefCnts.first);  // rorefcnt
4003   NameVals.push_back(SpecialRefCnts.second); // worefcnt
4004 
4005   for (auto &RI : FS->refs())
4006     NameVals.push_back(VE.getValueID(RI.getValue()));
4007 
4008   bool HasProfileData =
4009       F.hasProfileData() || ForceSummaryEdgesCold != FunctionSummary::FSHT_None;
4010   for (auto &ECI : FS->calls()) {
4011     NameVals.push_back(getValueId(ECI.first));
4012     if (HasProfileData)
4013       NameVals.push_back(static_cast<uint8_t>(ECI.second.Hotness));
4014     else if (WriteRelBFToSummary)
4015       NameVals.push_back(ECI.second.RelBlockFreq);
4016   }
4017 
4018   unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
4019   unsigned Code =
4020       (HasProfileData ? bitc::FS_PERMODULE_PROFILE
4021                       : (WriteRelBFToSummary ? bitc::FS_PERMODULE_RELBF
4022                                              : bitc::FS_PERMODULE));
4023 
4024   // Emit the finished record.
4025   Stream.EmitRecord(Code, NameVals, FSAbbrev);
4026   NameVals.clear();
4027 }
4028 
4029 // Collect the global value references in the given variable's initializer,
4030 // and emit them in a summary record.
4031 void ModuleBitcodeWriterBase::writeModuleLevelReferences(
4032     const GlobalVariable &V, SmallVector<uint64_t, 64> &NameVals,
4033     unsigned FSModRefsAbbrev, unsigned FSModVTableRefsAbbrev) {
4034   auto VI = Index->getValueInfo(V.getGUID());
4035   if (!VI || VI.getSummaryList().empty()) {
4036     // Only declarations should not have a summary (a declaration might however
4037     // have a summary if the def was in module level asm).
4038     assert(V.isDeclaration());
4039     return;
4040   }
4041   auto *Summary = VI.getSummaryList()[0].get();
4042   NameVals.push_back(VE.getValueID(&V));
4043   GlobalVarSummary *VS = cast<GlobalVarSummary>(Summary);
4044   NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
4045   NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
4046 
4047   auto VTableFuncs = VS->vTableFuncs();
4048   if (!VTableFuncs.empty())
4049     NameVals.push_back(VS->refs().size());
4050 
4051   unsigned SizeBeforeRefs = NameVals.size();
4052   for (auto &RI : VS->refs())
4053     NameVals.push_back(VE.getValueID(RI.getValue()));
4054   // Sort the refs for determinism output, the vector returned by FS->refs() has
4055   // been initialized from a DenseSet.
4056   llvm::sort(drop_begin(NameVals, SizeBeforeRefs));
4057 
4058   if (VTableFuncs.empty())
4059     Stream.EmitRecord(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS, NameVals,
4060                       FSModRefsAbbrev);
4061   else {
4062     // VTableFuncs pairs should already be sorted by offset.
4063     for (auto &P : VTableFuncs) {
4064       NameVals.push_back(VE.getValueID(P.FuncVI.getValue()));
4065       NameVals.push_back(P.VTableOffset);
4066     }
4067 
4068     Stream.EmitRecord(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS, NameVals,
4069                       FSModVTableRefsAbbrev);
4070   }
4071   NameVals.clear();
4072 }
4073 
4074 /// Emit the per-module summary section alongside the rest of
4075 /// the module's bitcode.
4076 void ModuleBitcodeWriterBase::writePerModuleGlobalValueSummary() {
4077   // By default we compile with ThinLTO if the module has a summary, but the
4078   // client can request full LTO with a module flag.
4079   bool IsThinLTO = true;
4080   if (auto *MD =
4081           mdconst::extract_or_null<ConstantInt>(M.getModuleFlag("ThinLTO")))
4082     IsThinLTO = MD->getZExtValue();
4083   Stream.EnterSubblock(IsThinLTO ? bitc::GLOBALVAL_SUMMARY_BLOCK_ID
4084                                  : bitc::FULL_LTO_GLOBALVAL_SUMMARY_BLOCK_ID,
4085                        4);
4086 
4087   Stream.EmitRecord(
4088       bitc::FS_VERSION,
4089       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
4090 
4091   // Write the index flags.
4092   uint64_t Flags = 0;
4093   // Bits 1-3 are set only in the combined index, skip them.
4094   if (Index->enableSplitLTOUnit())
4095     Flags |= 0x8;
4096   if (Index->hasUnifiedLTO())
4097     Flags |= 0x200;
4098 
4099   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Flags});
4100 
4101   if (Index->begin() == Index->end()) {
4102     Stream.ExitBlock();
4103     return;
4104   }
4105 
4106   for (const auto &GVI : valueIds()) {
4107     Stream.EmitRecord(bitc::FS_VALUE_GUID,
4108                       ArrayRef<uint64_t>{GVI.second, GVI.first});
4109   }
4110 
4111   if (!Index->stackIds().empty()) {
4112     auto StackIdAbbv = std::make_shared<BitCodeAbbrev>();
4113     StackIdAbbv->Add(BitCodeAbbrevOp(bitc::FS_STACK_IDS));
4114     // numids x stackid
4115     StackIdAbbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4116     StackIdAbbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4117     unsigned StackIdAbbvId = Stream.EmitAbbrev(std::move(StackIdAbbv));
4118     Stream.EmitRecord(bitc::FS_STACK_IDS, Index->stackIds(), StackIdAbbvId);
4119   }
4120 
4121   // Abbrev for FS_PERMODULE_PROFILE.
4122   auto Abbv = std::make_shared<BitCodeAbbrev>();
4123   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_PROFILE));
4124   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4125   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // flags
4126   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4127   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4128   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4129   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4130   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4131   // numrefs x valueid, n x (valueid, hotness)
4132   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4133   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4134   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4135 
4136   // Abbrev for FS_PERMODULE or FS_PERMODULE_RELBF.
4137   Abbv = std::make_shared<BitCodeAbbrev>();
4138   if (WriteRelBFToSummary)
4139     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_RELBF));
4140   else
4141     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE));
4142   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4143   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4144   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4145   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4146   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4147   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4148   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4149   // numrefs x valueid, n x (valueid [, rel_block_freq])
4150   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4151   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4152   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4153 
4154   // Abbrev for FS_PERMODULE_GLOBALVAR_INIT_REFS.
4155   Abbv = std::make_shared<BitCodeAbbrev>();
4156   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS));
4157   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
4158   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
4159   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));  // valueids
4160   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4161   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4162 
4163   // Abbrev for FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS.
4164   Abbv = std::make_shared<BitCodeAbbrev>();
4165   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS));
4166   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
4167   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
4168   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numrefs
4169   // numrefs x valueid, n x (valueid , offset)
4170   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4171   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4172   unsigned FSModVTableRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4173 
4174   // Abbrev for FS_ALIAS.
4175   Abbv = std::make_shared<BitCodeAbbrev>();
4176   Abbv->Add(BitCodeAbbrevOp(bitc::FS_ALIAS));
4177   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4178   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4179   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4180   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4181 
4182   // Abbrev for FS_TYPE_ID_METADATA
4183   Abbv = std::make_shared<BitCodeAbbrev>();
4184   Abbv->Add(BitCodeAbbrevOp(bitc::FS_TYPE_ID_METADATA));
4185   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid strtab index
4186   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid length
4187   // n x (valueid , offset)
4188   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4189   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4190   unsigned TypeIdCompatibleVtableAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4191 
4192   Abbv = std::make_shared<BitCodeAbbrev>();
4193   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_CALLSITE_INFO));
4194   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
4195   // n x stackidindex
4196   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4197   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4198   unsigned CallsiteAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4199 
4200   Abbv = std::make_shared<BitCodeAbbrev>();
4201   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_ALLOC_INFO));
4202   // n x (alloc type, numstackids, numstackids x stackidindex)
4203   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4204   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4205   unsigned AllocAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4206 
4207   SmallVector<uint64_t, 64> NameVals;
4208   // Iterate over the list of functions instead of the Index to
4209   // ensure the ordering is stable.
4210   for (const Function &F : M) {
4211     // Summary emission does not support anonymous functions, they have to
4212     // renamed using the anonymous function renaming pass.
4213     if (!F.hasName())
4214       report_fatal_error("Unexpected anonymous function when writing summary");
4215 
4216     ValueInfo VI = Index->getValueInfo(F.getGUID());
4217     if (!VI || VI.getSummaryList().empty()) {
4218       // Only declarations should not have a summary (a declaration might
4219       // however have a summary if the def was in module level asm).
4220       assert(F.isDeclaration());
4221       continue;
4222     }
4223     auto *Summary = VI.getSummaryList()[0].get();
4224     writePerModuleFunctionSummaryRecord(NameVals, Summary, VE.getValueID(&F),
4225                                         FSCallsAbbrev, FSCallsProfileAbbrev,
4226                                         CallsiteAbbrev, AllocAbbrev, F);
4227   }
4228 
4229   // Capture references from GlobalVariable initializers, which are outside
4230   // of a function scope.
4231   for (const GlobalVariable &G : M.globals())
4232     writeModuleLevelReferences(G, NameVals, FSModRefsAbbrev,
4233                                FSModVTableRefsAbbrev);
4234 
4235   for (const GlobalAlias &A : M.aliases()) {
4236     auto *Aliasee = A.getAliaseeObject();
4237     // Skip ifunc and nameless functions which don't have an entry in the
4238     // summary.
4239     if (!Aliasee->hasName() || isa<GlobalIFunc>(Aliasee))
4240       continue;
4241     auto AliasId = VE.getValueID(&A);
4242     auto AliaseeId = VE.getValueID(Aliasee);
4243     NameVals.push_back(AliasId);
4244     auto *Summary = Index->getGlobalValueSummary(A);
4245     AliasSummary *AS = cast<AliasSummary>(Summary);
4246     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
4247     NameVals.push_back(AliaseeId);
4248     Stream.EmitRecord(bitc::FS_ALIAS, NameVals, FSAliasAbbrev);
4249     NameVals.clear();
4250   }
4251 
4252   for (auto &S : Index->typeIdCompatibleVtableMap()) {
4253     writeTypeIdCompatibleVtableSummaryRecord(NameVals, StrtabBuilder, S.first,
4254                                              S.second, VE);
4255     Stream.EmitRecord(bitc::FS_TYPE_ID_METADATA, NameVals,
4256                       TypeIdCompatibleVtableAbbrev);
4257     NameVals.clear();
4258   }
4259 
4260   if (Index->getBlockCount())
4261     Stream.EmitRecord(bitc::FS_BLOCK_COUNT,
4262                       ArrayRef<uint64_t>{Index->getBlockCount()});
4263 
4264   Stream.ExitBlock();
4265 }
4266 
4267 /// Emit the combined summary section into the combined index file.
4268 void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
4269   Stream.EnterSubblock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID, 4);
4270   Stream.EmitRecord(
4271       bitc::FS_VERSION,
4272       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
4273 
4274   // Write the index flags.
4275   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Index.getFlags()});
4276 
4277   for (const auto &GVI : valueIds()) {
4278     Stream.EmitRecord(bitc::FS_VALUE_GUID,
4279                       ArrayRef<uint64_t>{GVI.second, GVI.first});
4280   }
4281 
4282   if (!StackIdIndices.empty()) {
4283     auto StackIdAbbv = std::make_shared<BitCodeAbbrev>();
4284     StackIdAbbv->Add(BitCodeAbbrevOp(bitc::FS_STACK_IDS));
4285     // numids x stackid
4286     StackIdAbbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4287     StackIdAbbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4288     unsigned StackIdAbbvId = Stream.EmitAbbrev(std::move(StackIdAbbv));
4289     // Write the stack ids used by this index, which will be a subset of those in
4290     // the full index in the case of distributed indexes.
4291     std::vector<uint64_t> StackIds;
4292     for (auto &I : StackIdIndices)
4293       StackIds.push_back(Index.getStackIdAtIndex(I));
4294     Stream.EmitRecord(bitc::FS_STACK_IDS, StackIds, StackIdAbbvId);
4295   }
4296 
4297   // Abbrev for FS_COMBINED.
4298   auto Abbv = std::make_shared<BitCodeAbbrev>();
4299   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED));
4300   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4301   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4302   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4303   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4304   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4305   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
4306   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4307   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4308   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4309   // numrefs x valueid, n x (valueid)
4310   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4311   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4312   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4313 
4314   // Abbrev for FS_COMBINED_PROFILE.
4315   Abbv = std::make_shared<BitCodeAbbrev>();
4316   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_PROFILE));
4317   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4318   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4319   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4320   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4321   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4322   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
4323   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4324   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4325   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4326   // numrefs x valueid, n x (valueid, hotness)
4327   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4328   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4329   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4330 
4331   // Abbrev for FS_COMBINED_GLOBALVAR_INIT_REFS.
4332   Abbv = std::make_shared<BitCodeAbbrev>();
4333   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS));
4334   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4335   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4336   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4337   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));    // valueids
4338   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4339   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4340 
4341   // Abbrev for FS_COMBINED_ALIAS.
4342   Abbv = std::make_shared<BitCodeAbbrev>();
4343   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_ALIAS));
4344   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4345   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4346   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4347   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4348   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4349 
4350   Abbv = std::make_shared<BitCodeAbbrev>();
4351   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_CALLSITE_INFO));
4352   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
4353   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numstackindices
4354   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numver
4355   // numstackindices x stackidindex, numver x version
4356   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4357   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4358   unsigned CallsiteAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4359 
4360   Abbv = std::make_shared<BitCodeAbbrev>();
4361   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_ALLOC_INFO));
4362   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // nummib
4363   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numver
4364   // nummib x (alloc type, numstackids, numstackids x stackidindex),
4365   // numver x version
4366   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4367   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4368   unsigned AllocAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4369 
4370   // The aliases are emitted as a post-pass, and will point to the value
4371   // id of the aliasee. Save them in a vector for post-processing.
4372   SmallVector<AliasSummary *, 64> Aliases;
4373 
4374   // Save the value id for each summary for alias emission.
4375   DenseMap<const GlobalValueSummary *, unsigned> SummaryToValueIdMap;
4376 
4377   SmallVector<uint64_t, 64> NameVals;
4378 
4379   // Set that will be populated during call to writeFunctionTypeMetadataRecords
4380   // with the type ids referenced by this index file.
4381   std::set<GlobalValue::GUID> ReferencedTypeIds;
4382 
4383   // For local linkage, we also emit the original name separately
4384   // immediately after the record.
4385   auto MaybeEmitOriginalName = [&](GlobalValueSummary &S) {
4386     // We don't need to emit the original name if we are writing the index for
4387     // distributed backends (in which case ModuleToSummariesForIndex is
4388     // non-null). The original name is only needed during the thin link, since
4389     // for SamplePGO the indirect call targets for local functions have
4390     // have the original name annotated in profile.
4391     // Continue to emit it when writing out the entire combined index, which is
4392     // used in testing the thin link via llvm-lto.
4393     if (ModuleToSummariesForIndex || !GlobalValue::isLocalLinkage(S.linkage()))
4394       return;
4395     NameVals.push_back(S.getOriginalName());
4396     Stream.EmitRecord(bitc::FS_COMBINED_ORIGINAL_NAME, NameVals);
4397     NameVals.clear();
4398   };
4399 
4400   std::set<GlobalValue::GUID> DefOrUseGUIDs;
4401   forEachSummary([&](GVInfo I, bool IsAliasee) {
4402     GlobalValueSummary *S = I.second;
4403     assert(S);
4404     DefOrUseGUIDs.insert(I.first);
4405     for (const ValueInfo &VI : S->refs())
4406       DefOrUseGUIDs.insert(VI.getGUID());
4407 
4408     auto ValueId = getValueId(I.first);
4409     assert(ValueId);
4410     SummaryToValueIdMap[S] = *ValueId;
4411 
4412     // If this is invoked for an aliasee, we want to record the above
4413     // mapping, but then not emit a summary entry (if the aliasee is
4414     // to be imported, we will invoke this separately with IsAliasee=false).
4415     if (IsAliasee)
4416       return;
4417 
4418     if (auto *AS = dyn_cast<AliasSummary>(S)) {
4419       // Will process aliases as a post-pass because the reader wants all
4420       // global to be loaded first.
4421       Aliases.push_back(AS);
4422       return;
4423     }
4424 
4425     if (auto *VS = dyn_cast<GlobalVarSummary>(S)) {
4426       NameVals.push_back(*ValueId);
4427       assert(ModuleIdMap.count(VS->modulePath()));
4428       NameVals.push_back(ModuleIdMap[VS->modulePath()]);
4429       NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
4430       NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
4431       for (auto &RI : VS->refs()) {
4432         auto RefValueId = getValueId(RI.getGUID());
4433         if (!RefValueId)
4434           continue;
4435         NameVals.push_back(*RefValueId);
4436       }
4437 
4438       // Emit the finished record.
4439       Stream.EmitRecord(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS, NameVals,
4440                         FSModRefsAbbrev);
4441       NameVals.clear();
4442       MaybeEmitOriginalName(*S);
4443       return;
4444     }
4445 
4446     auto GetValueId = [&](const ValueInfo &VI) -> std::optional<unsigned> {
4447       if (!VI)
4448         return std::nullopt;
4449       return getValueId(VI.getGUID());
4450     };
4451 
4452     auto *FS = cast<FunctionSummary>(S);
4453     writeFunctionTypeMetadataRecords(Stream, FS, GetValueId);
4454     getReferencedTypeIds(FS, ReferencedTypeIds);
4455 
4456     writeFunctionHeapProfileRecords(
4457         Stream, FS, CallsiteAbbrev, AllocAbbrev,
4458         /*PerModule*/ false,
4459         /*GetValueId*/ [&](const ValueInfo &VI) -> unsigned {
4460           std::optional<unsigned> ValueID = GetValueId(VI);
4461           // This can happen in shared index files for distributed ThinLTO if
4462           // the callee function summary is not included. Record 0 which we
4463           // will have to deal with conservatively when doing any kind of
4464           // validation in the ThinLTO backends.
4465           if (!ValueID)
4466             return 0;
4467           return *ValueID;
4468         },
4469         /*GetStackIndex*/ [&](unsigned I) {
4470           // Get the corresponding index into the list of StackIdIndices
4471           // actually being written for this combined index (which may be a
4472           // subset in the case of distributed indexes).
4473           auto Lower = llvm::lower_bound(StackIdIndices, I);
4474           return std::distance(StackIdIndices.begin(), Lower);
4475         });
4476 
4477     NameVals.push_back(*ValueId);
4478     assert(ModuleIdMap.count(FS->modulePath()));
4479     NameVals.push_back(ModuleIdMap[FS->modulePath()]);
4480     NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
4481     NameVals.push_back(FS->instCount());
4482     NameVals.push_back(getEncodedFFlags(FS->fflags()));
4483     NameVals.push_back(FS->entryCount());
4484 
4485     // Fill in below
4486     NameVals.push_back(0); // numrefs
4487     NameVals.push_back(0); // rorefcnt
4488     NameVals.push_back(0); // worefcnt
4489 
4490     unsigned Count = 0, RORefCnt = 0, WORefCnt = 0;
4491     for (auto &RI : FS->refs()) {
4492       auto RefValueId = getValueId(RI.getGUID());
4493       if (!RefValueId)
4494         continue;
4495       NameVals.push_back(*RefValueId);
4496       if (RI.isReadOnly())
4497         RORefCnt++;
4498       else if (RI.isWriteOnly())
4499         WORefCnt++;
4500       Count++;
4501     }
4502     NameVals[6] = Count;
4503     NameVals[7] = RORefCnt;
4504     NameVals[8] = WORefCnt;
4505 
4506     bool HasProfileData = false;
4507     for (auto &EI : FS->calls()) {
4508       HasProfileData |=
4509           EI.second.getHotness() != CalleeInfo::HotnessType::Unknown;
4510       if (HasProfileData)
4511         break;
4512     }
4513 
4514     for (auto &EI : FS->calls()) {
4515       // If this GUID doesn't have a value id, it doesn't have a function
4516       // summary and we don't need to record any calls to it.
4517       std::optional<unsigned> CallValueId = GetValueId(EI.first);
4518       if (!CallValueId)
4519         continue;
4520       NameVals.push_back(*CallValueId);
4521       if (HasProfileData)
4522         NameVals.push_back(static_cast<uint8_t>(EI.second.Hotness));
4523     }
4524 
4525     unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
4526     unsigned Code =
4527         (HasProfileData ? bitc::FS_COMBINED_PROFILE : bitc::FS_COMBINED);
4528 
4529     // Emit the finished record.
4530     Stream.EmitRecord(Code, NameVals, FSAbbrev);
4531     NameVals.clear();
4532     MaybeEmitOriginalName(*S);
4533   });
4534 
4535   for (auto *AS : Aliases) {
4536     auto AliasValueId = SummaryToValueIdMap[AS];
4537     assert(AliasValueId);
4538     NameVals.push_back(AliasValueId);
4539     assert(ModuleIdMap.count(AS->modulePath()));
4540     NameVals.push_back(ModuleIdMap[AS->modulePath()]);
4541     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
4542     auto AliaseeValueId = SummaryToValueIdMap[&AS->getAliasee()];
4543     assert(AliaseeValueId);
4544     NameVals.push_back(AliaseeValueId);
4545 
4546     // Emit the finished record.
4547     Stream.EmitRecord(bitc::FS_COMBINED_ALIAS, NameVals, FSAliasAbbrev);
4548     NameVals.clear();
4549     MaybeEmitOriginalName(*AS);
4550 
4551     if (auto *FS = dyn_cast<FunctionSummary>(&AS->getAliasee()))
4552       getReferencedTypeIds(FS, ReferencedTypeIds);
4553   }
4554 
4555   if (!Index.cfiFunctionDefs().empty()) {
4556     for (auto &S : Index.cfiFunctionDefs()) {
4557       if (DefOrUseGUIDs.count(
4558               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4559         NameVals.push_back(StrtabBuilder.add(S));
4560         NameVals.push_back(S.size());
4561       }
4562     }
4563     if (!NameVals.empty()) {
4564       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DEFS, NameVals);
4565       NameVals.clear();
4566     }
4567   }
4568 
4569   if (!Index.cfiFunctionDecls().empty()) {
4570     for (auto &S : Index.cfiFunctionDecls()) {
4571       if (DefOrUseGUIDs.count(
4572               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4573         NameVals.push_back(StrtabBuilder.add(S));
4574         NameVals.push_back(S.size());
4575       }
4576     }
4577     if (!NameVals.empty()) {
4578       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DECLS, NameVals);
4579       NameVals.clear();
4580     }
4581   }
4582 
4583   // Walk the GUIDs that were referenced, and write the
4584   // corresponding type id records.
4585   for (auto &T : ReferencedTypeIds) {
4586     auto TidIter = Index.typeIds().equal_range(T);
4587     for (auto It = TidIter.first; It != TidIter.second; ++It) {
4588       writeTypeIdSummaryRecord(NameVals, StrtabBuilder, It->second.first,
4589                                It->second.second);
4590       Stream.EmitRecord(bitc::FS_TYPE_ID, NameVals);
4591       NameVals.clear();
4592     }
4593   }
4594 
4595   if (Index.getBlockCount())
4596     Stream.EmitRecord(bitc::FS_BLOCK_COUNT,
4597                       ArrayRef<uint64_t>{Index.getBlockCount()});
4598 
4599   Stream.ExitBlock();
4600 }
4601 
4602 /// Create the "IDENTIFICATION_BLOCK_ID" containing a single string with the
4603 /// current llvm version, and a record for the epoch number.
4604 static void writeIdentificationBlock(BitstreamWriter &Stream) {
4605   Stream.EnterSubblock(bitc::IDENTIFICATION_BLOCK_ID, 5);
4606 
4607   // Write the "user readable" string identifying the bitcode producer
4608   auto Abbv = std::make_shared<BitCodeAbbrev>();
4609   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_STRING));
4610   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4611   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
4612   auto StringAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4613   writeStringRecord(Stream, bitc::IDENTIFICATION_CODE_STRING,
4614                     "LLVM" LLVM_VERSION_STRING, StringAbbrev);
4615 
4616   // Write the epoch version
4617   Abbv = std::make_shared<BitCodeAbbrev>();
4618   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_EPOCH));
4619   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
4620   auto EpochAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4621   constexpr std::array<unsigned, 1> Vals = {{bitc::BITCODE_CURRENT_EPOCH}};
4622   Stream.EmitRecord(bitc::IDENTIFICATION_CODE_EPOCH, Vals, EpochAbbrev);
4623   Stream.ExitBlock();
4624 }
4625 
4626 void ModuleBitcodeWriter::writeModuleHash(size_t BlockStartPos) {
4627   // Emit the module's hash.
4628   // MODULE_CODE_HASH: [5*i32]
4629   if (GenerateHash) {
4630     uint32_t Vals[5];
4631     Hasher.update(ArrayRef<uint8_t>((const uint8_t *)&(Buffer)[BlockStartPos],
4632                                     Buffer.size() - BlockStartPos));
4633     std::array<uint8_t, 20> Hash = Hasher.result();
4634     for (int Pos = 0; Pos < 20; Pos += 4) {
4635       Vals[Pos / 4] = support::endian::read32be(Hash.data() + Pos);
4636     }
4637 
4638     // Emit the finished record.
4639     Stream.EmitRecord(bitc::MODULE_CODE_HASH, Vals);
4640 
4641     if (ModHash)
4642       // Save the written hash value.
4643       llvm::copy(Vals, std::begin(*ModHash));
4644   }
4645 }
4646 
4647 void ModuleBitcodeWriter::write() {
4648   writeIdentificationBlock(Stream);
4649 
4650   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4651   size_t BlockStartPos = Buffer.size();
4652 
4653   writeModuleVersion();
4654 
4655   // Emit blockinfo, which defines the standard abbreviations etc.
4656   writeBlockInfo();
4657 
4658   // Emit information describing all of the types in the module.
4659   writeTypeTable();
4660 
4661   // Emit information about attribute groups.
4662   writeAttributeGroupTable();
4663 
4664   // Emit information about parameter attributes.
4665   writeAttributeTable();
4666 
4667   writeComdats();
4668 
4669   // Emit top-level description of module, including target triple, inline asm,
4670   // descriptors for global variables, and function prototype info.
4671   writeModuleInfo();
4672 
4673   // Emit constants.
4674   writeModuleConstants();
4675 
4676   // Emit metadata kind names.
4677   writeModuleMetadataKinds();
4678 
4679   // Emit metadata.
4680   writeModuleMetadata();
4681 
4682   // Emit module-level use-lists.
4683   if (VE.shouldPreserveUseListOrder())
4684     writeUseListBlock(nullptr);
4685 
4686   writeOperandBundleTags();
4687   writeSyncScopeNames();
4688 
4689   // Emit function bodies.
4690   DenseMap<const Function *, uint64_t> FunctionToBitcodeIndex;
4691   for (const Function &F : M)
4692     if (!F.isDeclaration())
4693       writeFunction(F, FunctionToBitcodeIndex);
4694 
4695   // Need to write after the above call to WriteFunction which populates
4696   // the summary information in the index.
4697   if (Index)
4698     writePerModuleGlobalValueSummary();
4699 
4700   writeGlobalValueSymbolTable(FunctionToBitcodeIndex);
4701 
4702   writeModuleHash(BlockStartPos);
4703 
4704   Stream.ExitBlock();
4705 }
4706 
4707 static void writeInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
4708                                uint32_t &Position) {
4709   support::endian::write32le(&Buffer[Position], Value);
4710   Position += 4;
4711 }
4712 
4713 /// If generating a bc file on darwin, we have to emit a
4714 /// header and trailer to make it compatible with the system archiver.  To do
4715 /// this we emit the following header, and then emit a trailer that pads the
4716 /// file out to be a multiple of 16 bytes.
4717 ///
4718 /// struct bc_header {
4719 ///   uint32_t Magic;         // 0x0B17C0DE
4720 ///   uint32_t Version;       // Version, currently always 0.
4721 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
4722 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
4723 ///   uint32_t CPUType;       // CPU specifier.
4724 ///   ... potentially more later ...
4725 /// };
4726 static void emitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
4727                                          const Triple &TT) {
4728   unsigned CPUType = ~0U;
4729 
4730   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
4731   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
4732   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
4733   // specific constants here because they are implicitly part of the Darwin ABI.
4734   enum {
4735     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
4736     DARWIN_CPU_TYPE_X86        = 7,
4737     DARWIN_CPU_TYPE_ARM        = 12,
4738     DARWIN_CPU_TYPE_POWERPC    = 18
4739   };
4740 
4741   Triple::ArchType Arch = TT.getArch();
4742   if (Arch == Triple::x86_64)
4743     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
4744   else if (Arch == Triple::x86)
4745     CPUType = DARWIN_CPU_TYPE_X86;
4746   else if (Arch == Triple::ppc)
4747     CPUType = DARWIN_CPU_TYPE_POWERPC;
4748   else if (Arch == Triple::ppc64)
4749     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
4750   else if (Arch == Triple::arm || Arch == Triple::thumb)
4751     CPUType = DARWIN_CPU_TYPE_ARM;
4752 
4753   // Traditional Bitcode starts after header.
4754   assert(Buffer.size() >= BWH_HeaderSize &&
4755          "Expected header size to be reserved");
4756   unsigned BCOffset = BWH_HeaderSize;
4757   unsigned BCSize = Buffer.size() - BWH_HeaderSize;
4758 
4759   // Write the magic and version.
4760   unsigned Position = 0;
4761   writeInt32ToBuffer(0x0B17C0DE, Buffer, Position);
4762   writeInt32ToBuffer(0, Buffer, Position); // Version.
4763   writeInt32ToBuffer(BCOffset, Buffer, Position);
4764   writeInt32ToBuffer(BCSize, Buffer, Position);
4765   writeInt32ToBuffer(CPUType, Buffer, Position);
4766 
4767   // If the file is not a multiple of 16 bytes, insert dummy padding.
4768   while (Buffer.size() & 15)
4769     Buffer.push_back(0);
4770 }
4771 
4772 /// Helper to write the header common to all bitcode files.
4773 static void writeBitcodeHeader(BitstreamWriter &Stream) {
4774   // Emit the file header.
4775   Stream.Emit((unsigned)'B', 8);
4776   Stream.Emit((unsigned)'C', 8);
4777   Stream.Emit(0x0, 4);
4778   Stream.Emit(0xC, 4);
4779   Stream.Emit(0xE, 4);
4780   Stream.Emit(0xD, 4);
4781 }
4782 
4783 BitcodeWriter::BitcodeWriter(SmallVectorImpl<char> &Buffer, raw_fd_stream *FS)
4784     : Buffer(Buffer), Stream(new BitstreamWriter(Buffer, FS, FlushThreshold)) {
4785   writeBitcodeHeader(*Stream);
4786 }
4787 
4788 BitcodeWriter::~BitcodeWriter() { assert(WroteStrtab); }
4789 
4790 void BitcodeWriter::writeBlob(unsigned Block, unsigned Record, StringRef Blob) {
4791   Stream->EnterSubblock(Block, 3);
4792 
4793   auto Abbv = std::make_shared<BitCodeAbbrev>();
4794   Abbv->Add(BitCodeAbbrevOp(Record));
4795   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
4796   auto AbbrevNo = Stream->EmitAbbrev(std::move(Abbv));
4797 
4798   Stream->EmitRecordWithBlob(AbbrevNo, ArrayRef<uint64_t>{Record}, Blob);
4799 
4800   Stream->ExitBlock();
4801 }
4802 
4803 void BitcodeWriter::writeSymtab() {
4804   assert(!WroteStrtab && !WroteSymtab);
4805 
4806   // If any module has module-level inline asm, we will require a registered asm
4807   // parser for the target so that we can create an accurate symbol table for
4808   // the module.
4809   for (Module *M : Mods) {
4810     if (M->getModuleInlineAsm().empty())
4811       continue;
4812 
4813     std::string Err;
4814     const Triple TT(M->getTargetTriple());
4815     const Target *T = TargetRegistry::lookupTarget(TT.str(), Err);
4816     if (!T || !T->hasMCAsmParser())
4817       return;
4818   }
4819 
4820   WroteSymtab = true;
4821   SmallVector<char, 0> Symtab;
4822   // The irsymtab::build function may be unable to create a symbol table if the
4823   // module is malformed (e.g. it contains an invalid alias). Writing a symbol
4824   // table is not required for correctness, but we still want to be able to
4825   // write malformed modules to bitcode files, so swallow the error.
4826   if (Error E = irsymtab::build(Mods, Symtab, StrtabBuilder, Alloc)) {
4827     consumeError(std::move(E));
4828     return;
4829   }
4830 
4831   writeBlob(bitc::SYMTAB_BLOCK_ID, bitc::SYMTAB_BLOB,
4832             {Symtab.data(), Symtab.size()});
4833 }
4834 
4835 void BitcodeWriter::writeStrtab() {
4836   assert(!WroteStrtab);
4837 
4838   std::vector<char> Strtab;
4839   StrtabBuilder.finalizeInOrder();
4840   Strtab.resize(StrtabBuilder.getSize());
4841   StrtabBuilder.write((uint8_t *)Strtab.data());
4842 
4843   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB,
4844             {Strtab.data(), Strtab.size()});
4845 
4846   WroteStrtab = true;
4847 }
4848 
4849 void BitcodeWriter::copyStrtab(StringRef Strtab) {
4850   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB, Strtab);
4851   WroteStrtab = true;
4852 }
4853 
4854 void BitcodeWriter::writeModule(const Module &M,
4855                                 bool ShouldPreserveUseListOrder,
4856                                 const ModuleSummaryIndex *Index,
4857                                 bool GenerateHash, ModuleHash *ModHash) {
4858   assert(!WroteStrtab);
4859 
4860   // The Mods vector is used by irsymtab::build, which requires non-const
4861   // Modules in case it needs to materialize metadata. But the bitcode writer
4862   // requires that the module is materialized, so we can cast to non-const here,
4863   // after checking that it is in fact materialized.
4864   assert(M.isMaterialized());
4865   Mods.push_back(const_cast<Module *>(&M));
4866 
4867   ModuleBitcodeWriter ModuleWriter(M, Buffer, StrtabBuilder, *Stream,
4868                                    ShouldPreserveUseListOrder, Index,
4869                                    GenerateHash, ModHash);
4870   ModuleWriter.write();
4871 }
4872 
4873 void BitcodeWriter::writeIndex(
4874     const ModuleSummaryIndex *Index,
4875     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4876   IndexBitcodeWriter IndexWriter(*Stream, StrtabBuilder, *Index,
4877                                  ModuleToSummariesForIndex);
4878   IndexWriter.write();
4879 }
4880 
4881 /// Write the specified module to the specified output stream.
4882 void llvm::WriteBitcodeToFile(const Module &M, raw_ostream &Out,
4883                               bool ShouldPreserveUseListOrder,
4884                               const ModuleSummaryIndex *Index,
4885                               bool GenerateHash, ModuleHash *ModHash) {
4886   SmallVector<char, 0> Buffer;
4887   Buffer.reserve(256*1024);
4888 
4889   // If this is darwin or another generic macho target, reserve space for the
4890   // header.
4891   Triple TT(M.getTargetTriple());
4892   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4893     Buffer.insert(Buffer.begin(), BWH_HeaderSize, 0);
4894 
4895   BitcodeWriter Writer(Buffer, dyn_cast<raw_fd_stream>(&Out));
4896   Writer.writeModule(M, ShouldPreserveUseListOrder, Index, GenerateHash,
4897                      ModHash);
4898   Writer.writeSymtab();
4899   Writer.writeStrtab();
4900 
4901   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4902     emitDarwinBCHeaderAndTrailer(Buffer, TT);
4903 
4904   // Write the generated bitstream to "Out".
4905   if (!Buffer.empty())
4906     Out.write((char *)&Buffer.front(), Buffer.size());
4907 }
4908 
4909 void IndexBitcodeWriter::write() {
4910   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4911 
4912   writeModuleVersion();
4913 
4914   // Write the module paths in the combined index.
4915   writeModStrings();
4916 
4917   // Write the summary combined index records.
4918   writeCombinedGlobalValueSummary();
4919 
4920   Stream.ExitBlock();
4921 }
4922 
4923 // Write the specified module summary index to the given raw output stream,
4924 // where it will be written in a new bitcode block. This is used when
4925 // writing the combined index file for ThinLTO. When writing a subset of the
4926 // index for a distributed backend, provide a \p ModuleToSummariesForIndex map.
4927 void llvm::writeIndexToFile(
4928     const ModuleSummaryIndex &Index, raw_ostream &Out,
4929     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4930   SmallVector<char, 0> Buffer;
4931   Buffer.reserve(256 * 1024);
4932 
4933   BitcodeWriter Writer(Buffer);
4934   Writer.writeIndex(&Index, ModuleToSummariesForIndex);
4935   Writer.writeStrtab();
4936 
4937   Out.write((char *)&Buffer.front(), Buffer.size());
4938 }
4939 
4940 namespace {
4941 
4942 /// Class to manage the bitcode writing for a thin link bitcode file.
4943 class ThinLinkBitcodeWriter : public ModuleBitcodeWriterBase {
4944   /// ModHash is for use in ThinLTO incremental build, generated while writing
4945   /// the module bitcode file.
4946   const ModuleHash *ModHash;
4947 
4948 public:
4949   ThinLinkBitcodeWriter(const Module &M, StringTableBuilder &StrtabBuilder,
4950                         BitstreamWriter &Stream,
4951                         const ModuleSummaryIndex &Index,
4952                         const ModuleHash &ModHash)
4953       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
4954                                 /*ShouldPreserveUseListOrder=*/false, &Index),
4955         ModHash(&ModHash) {}
4956 
4957   void write();
4958 
4959 private:
4960   void writeSimplifiedModuleInfo();
4961 };
4962 
4963 } // end anonymous namespace
4964 
4965 // This function writes a simpilified module info for thin link bitcode file.
4966 // It only contains the source file name along with the name(the offset and
4967 // size in strtab) and linkage for global values. For the global value info
4968 // entry, in order to keep linkage at offset 5, there are three zeros used
4969 // as padding.
4970 void ThinLinkBitcodeWriter::writeSimplifiedModuleInfo() {
4971   SmallVector<unsigned, 64> Vals;
4972   // Emit the module's source file name.
4973   {
4974     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
4975     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
4976     if (Bits == SE_Char6)
4977       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
4978     else if (Bits == SE_Fixed7)
4979       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
4980 
4981     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
4982     auto Abbv = std::make_shared<BitCodeAbbrev>();
4983     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
4984     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4985     Abbv->Add(AbbrevOpToUse);
4986     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4987 
4988     for (const auto P : M.getSourceFileName())
4989       Vals.push_back((unsigned char)P);
4990 
4991     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
4992     Vals.clear();
4993   }
4994 
4995   // Emit the global variable information.
4996   for (const GlobalVariable &GV : M.globals()) {
4997     // GLOBALVAR: [strtab offset, strtab size, 0, 0, 0, linkage]
4998     Vals.push_back(StrtabBuilder.add(GV.getName()));
4999     Vals.push_back(GV.getName().size());
5000     Vals.push_back(0);
5001     Vals.push_back(0);
5002     Vals.push_back(0);
5003     Vals.push_back(getEncodedLinkage(GV));
5004 
5005     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals);
5006     Vals.clear();
5007   }
5008 
5009   // Emit the function proto information.
5010   for (const Function &F : M) {
5011     // FUNCTION:  [strtab offset, strtab size, 0, 0, 0, linkage]
5012     Vals.push_back(StrtabBuilder.add(F.getName()));
5013     Vals.push_back(F.getName().size());
5014     Vals.push_back(0);
5015     Vals.push_back(0);
5016     Vals.push_back(0);
5017     Vals.push_back(getEncodedLinkage(F));
5018 
5019     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals);
5020     Vals.clear();
5021   }
5022 
5023   // Emit the alias information.
5024   for (const GlobalAlias &A : M.aliases()) {
5025     // ALIAS: [strtab offset, strtab size, 0, 0, 0, linkage]
5026     Vals.push_back(StrtabBuilder.add(A.getName()));
5027     Vals.push_back(A.getName().size());
5028     Vals.push_back(0);
5029     Vals.push_back(0);
5030     Vals.push_back(0);
5031     Vals.push_back(getEncodedLinkage(A));
5032 
5033     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals);
5034     Vals.clear();
5035   }
5036 
5037   // Emit the ifunc information.
5038   for (const GlobalIFunc &I : M.ifuncs()) {
5039     // IFUNC: [strtab offset, strtab size, 0, 0, 0, linkage]
5040     Vals.push_back(StrtabBuilder.add(I.getName()));
5041     Vals.push_back(I.getName().size());
5042     Vals.push_back(0);
5043     Vals.push_back(0);
5044     Vals.push_back(0);
5045     Vals.push_back(getEncodedLinkage(I));
5046 
5047     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
5048     Vals.clear();
5049   }
5050 }
5051 
5052 void ThinLinkBitcodeWriter::write() {
5053   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
5054 
5055   writeModuleVersion();
5056 
5057   writeSimplifiedModuleInfo();
5058 
5059   writePerModuleGlobalValueSummary();
5060 
5061   // Write module hash.
5062   Stream.EmitRecord(bitc::MODULE_CODE_HASH, ArrayRef<uint32_t>(*ModHash));
5063 
5064   Stream.ExitBlock();
5065 }
5066 
5067 void BitcodeWriter::writeThinLinkBitcode(const Module &M,
5068                                          const ModuleSummaryIndex &Index,
5069                                          const ModuleHash &ModHash) {
5070   assert(!WroteStrtab);
5071 
5072   // The Mods vector is used by irsymtab::build, which requires non-const
5073   // Modules in case it needs to materialize metadata. But the bitcode writer
5074   // requires that the module is materialized, so we can cast to non-const here,
5075   // after checking that it is in fact materialized.
5076   assert(M.isMaterialized());
5077   Mods.push_back(const_cast<Module *>(&M));
5078 
5079   ThinLinkBitcodeWriter ThinLinkWriter(M, StrtabBuilder, *Stream, Index,
5080                                        ModHash);
5081   ThinLinkWriter.write();
5082 }
5083 
5084 // Write the specified thin link bitcode file to the given raw output stream,
5085 // where it will be written in a new bitcode block. This is used when
5086 // writing the per-module index file for ThinLTO.
5087 void llvm::writeThinLinkBitcodeToFile(const Module &M, raw_ostream &Out,
5088                                       const ModuleSummaryIndex &Index,
5089                                       const ModuleHash &ModHash) {
5090   SmallVector<char, 0> Buffer;
5091   Buffer.reserve(256 * 1024);
5092 
5093   BitcodeWriter Writer(Buffer);
5094   Writer.writeThinLinkBitcode(M, Index, ModHash);
5095   Writer.writeSymtab();
5096   Writer.writeStrtab();
5097 
5098   Out.write((char *)&Buffer.front(), Buffer.size());
5099 }
5100 
5101 static const char *getSectionNameForBitcode(const Triple &T) {
5102   switch (T.getObjectFormat()) {
5103   case Triple::MachO:
5104     return "__LLVM,__bitcode";
5105   case Triple::COFF:
5106   case Triple::ELF:
5107   case Triple::Wasm:
5108   case Triple::UnknownObjectFormat:
5109     return ".llvmbc";
5110   case Triple::GOFF:
5111     llvm_unreachable("GOFF is not yet implemented");
5112     break;
5113   case Triple::SPIRV:
5114     llvm_unreachable("SPIRV is not yet implemented");
5115     break;
5116   case Triple::XCOFF:
5117     llvm_unreachable("XCOFF is not yet implemented");
5118     break;
5119   case Triple::DXContainer:
5120     llvm_unreachable("DXContainer is not yet implemented");
5121     break;
5122   }
5123   llvm_unreachable("Unimplemented ObjectFormatType");
5124 }
5125 
5126 static const char *getSectionNameForCommandline(const Triple &T) {
5127   switch (T.getObjectFormat()) {
5128   case Triple::MachO:
5129     return "__LLVM,__cmdline";
5130   case Triple::COFF:
5131   case Triple::ELF:
5132   case Triple::Wasm:
5133   case Triple::UnknownObjectFormat:
5134     return ".llvmcmd";
5135   case Triple::GOFF:
5136     llvm_unreachable("GOFF is not yet implemented");
5137     break;
5138   case Triple::SPIRV:
5139     llvm_unreachable("SPIRV is not yet implemented");
5140     break;
5141   case Triple::XCOFF:
5142     llvm_unreachable("XCOFF is not yet implemented");
5143     break;
5144   case Triple::DXContainer:
5145     llvm_unreachable("DXC is not yet implemented");
5146     break;
5147   }
5148   llvm_unreachable("Unimplemented ObjectFormatType");
5149 }
5150 
5151 void llvm::embedBitcodeInModule(llvm::Module &M, llvm::MemoryBufferRef Buf,
5152                                 bool EmbedBitcode, bool EmbedCmdline,
5153                                 const std::vector<uint8_t> &CmdArgs) {
5154   // Save llvm.compiler.used and remove it.
5155   SmallVector<Constant *, 2> UsedArray;
5156   SmallVector<GlobalValue *, 4> UsedGlobals;
5157   Type *UsedElementType = Type::getInt8PtrTy(M.getContext());
5158   GlobalVariable *Used = collectUsedGlobalVariables(M, UsedGlobals, true);
5159   for (auto *GV : UsedGlobals) {
5160     if (GV->getName() != "llvm.embedded.module" &&
5161         GV->getName() != "llvm.cmdline")
5162       UsedArray.push_back(
5163           ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
5164   }
5165   if (Used)
5166     Used->eraseFromParent();
5167 
5168   // Embed the bitcode for the llvm module.
5169   std::string Data;
5170   ArrayRef<uint8_t> ModuleData;
5171   Triple T(M.getTargetTriple());
5172 
5173   if (EmbedBitcode) {
5174     if (Buf.getBufferSize() == 0 ||
5175         !isBitcode((const unsigned char *)Buf.getBufferStart(),
5176                    (const unsigned char *)Buf.getBufferEnd())) {
5177       // If the input is LLVM Assembly, bitcode is produced by serializing
5178       // the module. Use-lists order need to be preserved in this case.
5179       llvm::raw_string_ostream OS(Data);
5180       llvm::WriteBitcodeToFile(M, OS, /* ShouldPreserveUseListOrder */ true);
5181       ModuleData =
5182           ArrayRef<uint8_t>((const uint8_t *)OS.str().data(), OS.str().size());
5183     } else
5184       // If the input is LLVM bitcode, write the input byte stream directly.
5185       ModuleData = ArrayRef<uint8_t>((const uint8_t *)Buf.getBufferStart(),
5186                                      Buf.getBufferSize());
5187   }
5188   llvm::Constant *ModuleConstant =
5189       llvm::ConstantDataArray::get(M.getContext(), ModuleData);
5190   llvm::GlobalVariable *GV = new llvm::GlobalVariable(
5191       M, ModuleConstant->getType(), true, llvm::GlobalValue::PrivateLinkage,
5192       ModuleConstant);
5193   GV->setSection(getSectionNameForBitcode(T));
5194   // Set alignment to 1 to prevent padding between two contributions from input
5195   // sections after linking.
5196   GV->setAlignment(Align(1));
5197   UsedArray.push_back(
5198       ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
5199   if (llvm::GlobalVariable *Old =
5200           M.getGlobalVariable("llvm.embedded.module", true)) {
5201     assert(Old->hasZeroLiveUses() &&
5202            "llvm.embedded.module can only be used once in llvm.compiler.used");
5203     GV->takeName(Old);
5204     Old->eraseFromParent();
5205   } else {
5206     GV->setName("llvm.embedded.module");
5207   }
5208 
5209   // Skip if only bitcode needs to be embedded.
5210   if (EmbedCmdline) {
5211     // Embed command-line options.
5212     ArrayRef<uint8_t> CmdData(const_cast<uint8_t *>(CmdArgs.data()),
5213                               CmdArgs.size());
5214     llvm::Constant *CmdConstant =
5215         llvm::ConstantDataArray::get(M.getContext(), CmdData);
5216     GV = new llvm::GlobalVariable(M, CmdConstant->getType(), true,
5217                                   llvm::GlobalValue::PrivateLinkage,
5218                                   CmdConstant);
5219     GV->setSection(getSectionNameForCommandline(T));
5220     GV->setAlignment(Align(1));
5221     UsedArray.push_back(
5222         ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
5223     if (llvm::GlobalVariable *Old = M.getGlobalVariable("llvm.cmdline", true)) {
5224       assert(Old->hasZeroLiveUses() &&
5225              "llvm.cmdline can only be used once in llvm.compiler.used");
5226       GV->takeName(Old);
5227       Old->eraseFromParent();
5228     } else {
5229       GV->setName("llvm.cmdline");
5230     }
5231   }
5232 
5233   if (UsedArray.empty())
5234     return;
5235 
5236   // Recreate llvm.compiler.used.
5237   ArrayType *ATy = ArrayType::get(UsedElementType, UsedArray.size());
5238   auto *NewUsed = new GlobalVariable(
5239       M, ATy, false, llvm::GlobalValue::AppendingLinkage,
5240       llvm::ConstantArray::get(ATy, UsedArray), "llvm.compiler.used");
5241   NewUsed->setSection("llvm.metadata");
5242 }
5243