xref: /freebsd-src/contrib/llvm-project/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp (revision cb14a3fe5122c879eae1fb480ed7ce82a699ddb6)
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_CAST_FLAGS_ABBREV,
127   FUNCTION_INST_RET_VOID_ABBREV,
128   FUNCTION_INST_RET_VAL_ABBREV,
129   FUNCTION_INST_UNREACHABLE_ABBREV,
130   FUNCTION_INST_GEP_ABBREV,
131 };
132 
133 /// Abstract class to manage the bitcode writing, subclassed for each bitcode
134 /// file type.
135 class BitcodeWriterBase {
136 protected:
137   /// The stream created and owned by the client.
138   BitstreamWriter &Stream;
139 
140   StringTableBuilder &StrtabBuilder;
141 
142 public:
143   /// Constructs a BitcodeWriterBase object that writes to the provided
144   /// \p Stream.
145   BitcodeWriterBase(BitstreamWriter &Stream, StringTableBuilder &StrtabBuilder)
146       : Stream(Stream), StrtabBuilder(StrtabBuilder) {}
147 
148 protected:
149   void writeModuleVersion();
150 };
151 
152 void BitcodeWriterBase::writeModuleVersion() {
153   // VERSION: [version#]
154   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, ArrayRef<uint64_t>{2});
155 }
156 
157 /// Base class to manage the module bitcode writing, currently subclassed for
158 /// ModuleBitcodeWriter and ThinLinkBitcodeWriter.
159 class ModuleBitcodeWriterBase : public BitcodeWriterBase {
160 protected:
161   /// The Module to write to bitcode.
162   const Module &M;
163 
164   /// Enumerates ids for all values in the module.
165   ValueEnumerator VE;
166 
167   /// Optional per-module index to write for ThinLTO.
168   const ModuleSummaryIndex *Index;
169 
170   /// Map that holds the correspondence between GUIDs in the summary index,
171   /// that came from indirect call profiles, and a value id generated by this
172   /// class to use in the VST and summary block records.
173   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
174 
175   /// Tracks the last value id recorded in the GUIDToValueMap.
176   unsigned GlobalValueId;
177 
178   /// Saves the offset of the VSTOffset record that must eventually be
179   /// backpatched with the offset of the actual VST.
180   uint64_t VSTOffsetPlaceholder = 0;
181 
182 public:
183   /// Constructs a ModuleBitcodeWriterBase object for the given Module,
184   /// writing to the provided \p Buffer.
185   ModuleBitcodeWriterBase(const Module &M, StringTableBuilder &StrtabBuilder,
186                           BitstreamWriter &Stream,
187                           bool ShouldPreserveUseListOrder,
188                           const ModuleSummaryIndex *Index)
189       : BitcodeWriterBase(Stream, StrtabBuilder), M(M),
190         VE(M, ShouldPreserveUseListOrder), Index(Index) {
191     // Assign ValueIds to any callee values in the index that came from
192     // indirect call profiles and were recorded as a GUID not a Value*
193     // (which would have been assigned an ID by the ValueEnumerator).
194     // The starting ValueId is just after the number of values in the
195     // ValueEnumerator, so that they can be emitted in the VST.
196     GlobalValueId = VE.getValues().size();
197     if (!Index)
198       return;
199     for (const auto &GUIDSummaryLists : *Index)
200       // Examine all summaries for this GUID.
201       for (auto &Summary : GUIDSummaryLists.second.SummaryList)
202         if (auto FS = dyn_cast<FunctionSummary>(Summary.get()))
203           // For each call in the function summary, see if the call
204           // is to a GUID (which means it is for an indirect call,
205           // otherwise we would have a Value for it). If so, synthesize
206           // a value id.
207           for (auto &CallEdge : FS->calls())
208             if (!CallEdge.first.haveGVs() || !CallEdge.first.getValue())
209               assignValueId(CallEdge.first.getGUID());
210   }
211 
212 protected:
213   void writePerModuleGlobalValueSummary();
214 
215 private:
216   void writePerModuleFunctionSummaryRecord(
217       SmallVector<uint64_t, 64> &NameVals, GlobalValueSummary *Summary,
218       unsigned ValueID, unsigned FSCallsAbbrev, unsigned FSCallsProfileAbbrev,
219       unsigned CallsiteAbbrev, unsigned AllocAbbrev, const Function &F);
220   void writeModuleLevelReferences(const GlobalVariable &V,
221                                   SmallVector<uint64_t, 64> &NameVals,
222                                   unsigned FSModRefsAbbrev,
223                                   unsigned FSModVTableRefsAbbrev);
224 
225   void assignValueId(GlobalValue::GUID ValGUID) {
226     GUIDToValueIdMap[ValGUID] = ++GlobalValueId;
227   }
228 
229   unsigned getValueId(GlobalValue::GUID ValGUID) {
230     const auto &VMI = GUIDToValueIdMap.find(ValGUID);
231     // Expect that any GUID value had a value Id assigned by an
232     // earlier call to assignValueId.
233     assert(VMI != GUIDToValueIdMap.end() &&
234            "GUID does not have assigned value Id");
235     return VMI->second;
236   }
237 
238   // Helper to get the valueId for the type of value recorded in VI.
239   unsigned getValueId(ValueInfo VI) {
240     if (!VI.haveGVs() || !VI.getValue())
241       return getValueId(VI.getGUID());
242     return VE.getValueID(VI.getValue());
243   }
244 
245   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
246 };
247 
248 /// Class to manage the bitcode writing for a module.
249 class ModuleBitcodeWriter : public ModuleBitcodeWriterBase {
250   /// Pointer to the buffer allocated by caller for bitcode writing.
251   const SmallVectorImpl<char> &Buffer;
252 
253   /// True if a module hash record should be written.
254   bool GenerateHash;
255 
256   /// If non-null, when GenerateHash is true, the resulting hash is written
257   /// into ModHash.
258   ModuleHash *ModHash;
259 
260   SHA1 Hasher;
261 
262   /// The start bit of the identification block.
263   uint64_t BitcodeStartBit;
264 
265 public:
266   /// Constructs a ModuleBitcodeWriter object for the given Module,
267   /// writing to the provided \p Buffer.
268   ModuleBitcodeWriter(const Module &M, SmallVectorImpl<char> &Buffer,
269                       StringTableBuilder &StrtabBuilder,
270                       BitstreamWriter &Stream, bool ShouldPreserveUseListOrder,
271                       const ModuleSummaryIndex *Index, bool GenerateHash,
272                       ModuleHash *ModHash = nullptr)
273       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
274                                 ShouldPreserveUseListOrder, Index),
275         Buffer(Buffer), GenerateHash(GenerateHash), ModHash(ModHash),
276         BitcodeStartBit(Stream.GetCurrentBitNo()) {}
277 
278   /// Emit the current module to the bitstream.
279   void write();
280 
281 private:
282   uint64_t bitcodeStartBit() { return BitcodeStartBit; }
283 
284   size_t addToStrtab(StringRef Str);
285 
286   void writeAttributeGroupTable();
287   void writeAttributeTable();
288   void writeTypeTable();
289   void writeComdats();
290   void writeValueSymbolTableForwardDecl();
291   void writeModuleInfo();
292   void writeValueAsMetadata(const ValueAsMetadata *MD,
293                             SmallVectorImpl<uint64_t> &Record);
294   void writeMDTuple(const MDTuple *N, SmallVectorImpl<uint64_t> &Record,
295                     unsigned Abbrev);
296   unsigned createDILocationAbbrev();
297   void writeDILocation(const DILocation *N, SmallVectorImpl<uint64_t> &Record,
298                        unsigned &Abbrev);
299   unsigned createGenericDINodeAbbrev();
300   void writeGenericDINode(const GenericDINode *N,
301                           SmallVectorImpl<uint64_t> &Record, unsigned &Abbrev);
302   void writeDISubrange(const DISubrange *N, SmallVectorImpl<uint64_t> &Record,
303                        unsigned Abbrev);
304   void writeDIGenericSubrange(const DIGenericSubrange *N,
305                               SmallVectorImpl<uint64_t> &Record,
306                               unsigned Abbrev);
307   void writeDIEnumerator(const DIEnumerator *N,
308                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
309   void writeDIBasicType(const DIBasicType *N, SmallVectorImpl<uint64_t> &Record,
310                         unsigned Abbrev);
311   void writeDIStringType(const DIStringType *N,
312                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
313   void writeDIDerivedType(const DIDerivedType *N,
314                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
315   void writeDICompositeType(const DICompositeType *N,
316                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
317   void writeDISubroutineType(const DISubroutineType *N,
318                              SmallVectorImpl<uint64_t> &Record,
319                              unsigned Abbrev);
320   void writeDIFile(const DIFile *N, SmallVectorImpl<uint64_t> &Record,
321                    unsigned Abbrev);
322   void writeDICompileUnit(const DICompileUnit *N,
323                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
324   void writeDISubprogram(const DISubprogram *N,
325                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
326   void writeDILexicalBlock(const DILexicalBlock *N,
327                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
328   void writeDILexicalBlockFile(const DILexicalBlockFile *N,
329                                SmallVectorImpl<uint64_t> &Record,
330                                unsigned Abbrev);
331   void writeDICommonBlock(const DICommonBlock *N,
332                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
333   void writeDINamespace(const DINamespace *N, SmallVectorImpl<uint64_t> &Record,
334                         unsigned Abbrev);
335   void writeDIMacro(const DIMacro *N, SmallVectorImpl<uint64_t> &Record,
336                     unsigned Abbrev);
337   void writeDIMacroFile(const DIMacroFile *N, SmallVectorImpl<uint64_t> &Record,
338                         unsigned Abbrev);
339   void writeDIArgList(const DIArgList *N, SmallVectorImpl<uint64_t> &Record);
340   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::Writable:
827     return bitc::ATTR_KIND_WRITABLE;
828   case Attribute::CoroDestroyOnlyWhenComplete:
829     return bitc::ATTR_KIND_CORO_ONLY_DESTROY_WHEN_COMPLETE;
830   case Attribute::DeadOnUnwind:
831     return bitc::ATTR_KIND_DEAD_ON_UNWIND;
832   case Attribute::EndAttrKinds:
833     llvm_unreachable("Can not encode end-attribute kinds marker.");
834   case Attribute::None:
835     llvm_unreachable("Can not encode none-attribute.");
836   case Attribute::EmptyKey:
837   case Attribute::TombstoneKey:
838     llvm_unreachable("Trying to encode EmptyKey/TombstoneKey");
839   }
840 
841   llvm_unreachable("Trying to encode unknown attribute");
842 }
843 
844 void ModuleBitcodeWriter::writeAttributeGroupTable() {
845   const std::vector<ValueEnumerator::IndexAndAttrSet> &AttrGrps =
846       VE.getAttributeGroups();
847   if (AttrGrps.empty()) return;
848 
849   Stream.EnterSubblock(bitc::PARAMATTR_GROUP_BLOCK_ID, 3);
850 
851   SmallVector<uint64_t, 64> Record;
852   for (ValueEnumerator::IndexAndAttrSet Pair : AttrGrps) {
853     unsigned AttrListIndex = Pair.first;
854     AttributeSet AS = Pair.second;
855     Record.push_back(VE.getAttributeGroupID(Pair));
856     Record.push_back(AttrListIndex);
857 
858     for (Attribute Attr : AS) {
859       if (Attr.isEnumAttribute()) {
860         Record.push_back(0);
861         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
862       } else if (Attr.isIntAttribute()) {
863         Record.push_back(1);
864         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
865         Record.push_back(Attr.getValueAsInt());
866       } else if (Attr.isStringAttribute()) {
867         StringRef Kind = Attr.getKindAsString();
868         StringRef Val = Attr.getValueAsString();
869 
870         Record.push_back(Val.empty() ? 3 : 4);
871         Record.append(Kind.begin(), Kind.end());
872         Record.push_back(0);
873         if (!Val.empty()) {
874           Record.append(Val.begin(), Val.end());
875           Record.push_back(0);
876         }
877       } else {
878         assert(Attr.isTypeAttribute());
879         Type *Ty = Attr.getValueAsType();
880         Record.push_back(Ty ? 6 : 5);
881         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
882         if (Ty)
883           Record.push_back(VE.getTypeID(Attr.getValueAsType()));
884       }
885     }
886 
887     Stream.EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
888     Record.clear();
889   }
890 
891   Stream.ExitBlock();
892 }
893 
894 void ModuleBitcodeWriter::writeAttributeTable() {
895   const std::vector<AttributeList> &Attrs = VE.getAttributeLists();
896   if (Attrs.empty()) return;
897 
898   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
899 
900   SmallVector<uint64_t, 64> Record;
901   for (const AttributeList &AL : Attrs) {
902     for (unsigned i : AL.indexes()) {
903       AttributeSet AS = AL.getAttributes(i);
904       if (AS.hasAttributes())
905         Record.push_back(VE.getAttributeGroupID({i, AS}));
906     }
907 
908     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
909     Record.clear();
910   }
911 
912   Stream.ExitBlock();
913 }
914 
915 /// WriteTypeTable - Write out the type table for a module.
916 void ModuleBitcodeWriter::writeTypeTable() {
917   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
918 
919   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
920   SmallVector<uint64_t, 64> TypeVals;
921 
922   uint64_t NumBits = VE.computeBitsRequiredForTypeIndicies();
923 
924   // Abbrev for TYPE_CODE_OPAQUE_POINTER.
925   auto Abbv = std::make_shared<BitCodeAbbrev>();
926   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_OPAQUE_POINTER));
927   Abbv->Add(BitCodeAbbrevOp(0)); // Addrspace = 0
928   unsigned OpaquePtrAbbrev = Stream.EmitAbbrev(std::move(Abbv));
929 
930   // Abbrev for TYPE_CODE_FUNCTION.
931   Abbv = std::make_shared<BitCodeAbbrev>();
932   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
933   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
934   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
935   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
936   unsigned FunctionAbbrev = Stream.EmitAbbrev(std::move(Abbv));
937 
938   // Abbrev for TYPE_CODE_STRUCT_ANON.
939   Abbv = std::make_shared<BitCodeAbbrev>();
940   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
941   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
942   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
943   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
944   unsigned StructAnonAbbrev = Stream.EmitAbbrev(std::move(Abbv));
945 
946   // Abbrev for TYPE_CODE_STRUCT_NAME.
947   Abbv = std::make_shared<BitCodeAbbrev>();
948   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
949   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
950   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
951   unsigned StructNameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
952 
953   // Abbrev for TYPE_CODE_STRUCT_NAMED.
954   Abbv = std::make_shared<BitCodeAbbrev>();
955   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
956   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
957   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
958   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
959   unsigned StructNamedAbbrev = Stream.EmitAbbrev(std::move(Abbv));
960 
961   // Abbrev for TYPE_CODE_ARRAY.
962   Abbv = std::make_shared<BitCodeAbbrev>();
963   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
964   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
965   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
966   unsigned ArrayAbbrev = Stream.EmitAbbrev(std::move(Abbv));
967 
968   // Emit an entry count so the reader can reserve space.
969   TypeVals.push_back(TypeList.size());
970   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
971   TypeVals.clear();
972 
973   // Loop over all of the types, emitting each in turn.
974   for (Type *T : TypeList) {
975     int AbbrevToUse = 0;
976     unsigned Code = 0;
977 
978     switch (T->getTypeID()) {
979     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;      break;
980     case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;      break;
981     case Type::BFloatTyID:    Code = bitc::TYPE_CODE_BFLOAT;    break;
982     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;     break;
983     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE;    break;
984     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80;  break;
985     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128;     break;
986     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
987     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;     break;
988     case Type::MetadataTyID:  Code = bitc::TYPE_CODE_METADATA;  break;
989     case Type::X86_MMXTyID:   Code = bitc::TYPE_CODE_X86_MMX;   break;
990     case Type::X86_AMXTyID:   Code = bitc::TYPE_CODE_X86_AMX;   break;
991     case Type::TokenTyID:     Code = bitc::TYPE_CODE_TOKEN;     break;
992     case Type::IntegerTyID:
993       // INTEGER: [width]
994       Code = bitc::TYPE_CODE_INTEGER;
995       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
996       break;
997     case Type::PointerTyID: {
998       PointerType *PTy = cast<PointerType>(T);
999       unsigned AddressSpace = PTy->getAddressSpace();
1000       // OPAQUE_POINTER: [address space]
1001       Code = bitc::TYPE_CODE_OPAQUE_POINTER;
1002       TypeVals.push_back(AddressSpace);
1003       if (AddressSpace == 0)
1004         AbbrevToUse = OpaquePtrAbbrev;
1005       break;
1006     }
1007     case Type::FunctionTyID: {
1008       FunctionType *FT = cast<FunctionType>(T);
1009       // FUNCTION: [isvararg, retty, paramty x N]
1010       Code = bitc::TYPE_CODE_FUNCTION;
1011       TypeVals.push_back(FT->isVarArg());
1012       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
1013       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
1014         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
1015       AbbrevToUse = FunctionAbbrev;
1016       break;
1017     }
1018     case Type::StructTyID: {
1019       StructType *ST = cast<StructType>(T);
1020       // STRUCT: [ispacked, eltty x N]
1021       TypeVals.push_back(ST->isPacked());
1022       // Output all of the element types.
1023       for (Type *ET : ST->elements())
1024         TypeVals.push_back(VE.getTypeID(ET));
1025 
1026       if (ST->isLiteral()) {
1027         Code = bitc::TYPE_CODE_STRUCT_ANON;
1028         AbbrevToUse = StructAnonAbbrev;
1029       } else {
1030         if (ST->isOpaque()) {
1031           Code = bitc::TYPE_CODE_OPAQUE;
1032         } else {
1033           Code = bitc::TYPE_CODE_STRUCT_NAMED;
1034           AbbrevToUse = StructNamedAbbrev;
1035         }
1036 
1037         // Emit the name if it is present.
1038         if (!ST->getName().empty())
1039           writeStringRecord(Stream, bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
1040                             StructNameAbbrev);
1041       }
1042       break;
1043     }
1044     case Type::ArrayTyID: {
1045       ArrayType *AT = cast<ArrayType>(T);
1046       // ARRAY: [numelts, eltty]
1047       Code = bitc::TYPE_CODE_ARRAY;
1048       TypeVals.push_back(AT->getNumElements());
1049       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
1050       AbbrevToUse = ArrayAbbrev;
1051       break;
1052     }
1053     case Type::FixedVectorTyID:
1054     case Type::ScalableVectorTyID: {
1055       VectorType *VT = cast<VectorType>(T);
1056       // VECTOR [numelts, eltty] or
1057       //        [numelts, eltty, scalable]
1058       Code = bitc::TYPE_CODE_VECTOR;
1059       TypeVals.push_back(VT->getElementCount().getKnownMinValue());
1060       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
1061       if (isa<ScalableVectorType>(VT))
1062         TypeVals.push_back(true);
1063       break;
1064     }
1065     case Type::TargetExtTyID: {
1066       TargetExtType *TET = cast<TargetExtType>(T);
1067       Code = bitc::TYPE_CODE_TARGET_TYPE;
1068       writeStringRecord(Stream, bitc::TYPE_CODE_STRUCT_NAME, TET->getName(),
1069                         StructNameAbbrev);
1070       TypeVals.push_back(TET->getNumTypeParameters());
1071       for (Type *InnerTy : TET->type_params())
1072         TypeVals.push_back(VE.getTypeID(InnerTy));
1073       for (unsigned IntParam : TET->int_params())
1074         TypeVals.push_back(IntParam);
1075       break;
1076     }
1077     case Type::TypedPointerTyID:
1078       llvm_unreachable("Typed pointers cannot be added to IR modules");
1079     }
1080 
1081     // Emit the finished record.
1082     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
1083     TypeVals.clear();
1084   }
1085 
1086   Stream.ExitBlock();
1087 }
1088 
1089 static unsigned getEncodedLinkage(const GlobalValue::LinkageTypes Linkage) {
1090   switch (Linkage) {
1091   case GlobalValue::ExternalLinkage:
1092     return 0;
1093   case GlobalValue::WeakAnyLinkage:
1094     return 16;
1095   case GlobalValue::AppendingLinkage:
1096     return 2;
1097   case GlobalValue::InternalLinkage:
1098     return 3;
1099   case GlobalValue::LinkOnceAnyLinkage:
1100     return 18;
1101   case GlobalValue::ExternalWeakLinkage:
1102     return 7;
1103   case GlobalValue::CommonLinkage:
1104     return 8;
1105   case GlobalValue::PrivateLinkage:
1106     return 9;
1107   case GlobalValue::WeakODRLinkage:
1108     return 17;
1109   case GlobalValue::LinkOnceODRLinkage:
1110     return 19;
1111   case GlobalValue::AvailableExternallyLinkage:
1112     return 12;
1113   }
1114   llvm_unreachable("Invalid linkage");
1115 }
1116 
1117 static unsigned getEncodedLinkage(const GlobalValue &GV) {
1118   return getEncodedLinkage(GV.getLinkage());
1119 }
1120 
1121 static uint64_t getEncodedFFlags(FunctionSummary::FFlags Flags) {
1122   uint64_t RawFlags = 0;
1123   RawFlags |= Flags.ReadNone;
1124   RawFlags |= (Flags.ReadOnly << 1);
1125   RawFlags |= (Flags.NoRecurse << 2);
1126   RawFlags |= (Flags.ReturnDoesNotAlias << 3);
1127   RawFlags |= (Flags.NoInline << 4);
1128   RawFlags |= (Flags.AlwaysInline << 5);
1129   RawFlags |= (Flags.NoUnwind << 6);
1130   RawFlags |= (Flags.MayThrow << 7);
1131   RawFlags |= (Flags.HasUnknownCall << 8);
1132   RawFlags |= (Flags.MustBeUnreachable << 9);
1133   return RawFlags;
1134 }
1135 
1136 // Decode the flags for GlobalValue in the summary. See getDecodedGVSummaryFlags
1137 // in BitcodeReader.cpp.
1138 static uint64_t getEncodedGVSummaryFlags(GlobalValueSummary::GVFlags Flags) {
1139   uint64_t RawFlags = 0;
1140 
1141   RawFlags |= Flags.NotEligibleToImport; // bool
1142   RawFlags |= (Flags.Live << 1);
1143   RawFlags |= (Flags.DSOLocal << 2);
1144   RawFlags |= (Flags.CanAutoHide << 3);
1145 
1146   // Linkage don't need to be remapped at that time for the summary. Any future
1147   // change to the getEncodedLinkage() function will need to be taken into
1148   // account here as well.
1149   RawFlags = (RawFlags << 4) | Flags.Linkage; // 4 bits
1150 
1151   RawFlags |= (Flags.Visibility << 8); // 2 bits
1152 
1153   return RawFlags;
1154 }
1155 
1156 static uint64_t getEncodedGVarFlags(GlobalVarSummary::GVarFlags Flags) {
1157   uint64_t RawFlags = Flags.MaybeReadOnly | (Flags.MaybeWriteOnly << 1) |
1158                       (Flags.Constant << 2) | Flags.VCallVisibility << 3;
1159   return RawFlags;
1160 }
1161 
1162 static uint64_t getEncodedHotnessCallEdgeInfo(const CalleeInfo &CI) {
1163   uint64_t RawFlags = 0;
1164 
1165   RawFlags |= CI.Hotness;            // 3 bits
1166   RawFlags |= (CI.HasTailCall << 3); // 1 bit
1167 
1168   return RawFlags;
1169 }
1170 
1171 static uint64_t getEncodedRelBFCallEdgeInfo(const CalleeInfo &CI) {
1172   uint64_t RawFlags = 0;
1173 
1174   RawFlags |= CI.RelBlockFreq; // CalleeInfo::RelBlockFreqBits bits
1175   RawFlags |= (CI.HasTailCall << CalleeInfo::RelBlockFreqBits); // 1 bit
1176 
1177   return RawFlags;
1178 }
1179 
1180 static unsigned getEncodedVisibility(const GlobalValue &GV) {
1181   switch (GV.getVisibility()) {
1182   case GlobalValue::DefaultVisibility:   return 0;
1183   case GlobalValue::HiddenVisibility:    return 1;
1184   case GlobalValue::ProtectedVisibility: return 2;
1185   }
1186   llvm_unreachable("Invalid visibility");
1187 }
1188 
1189 static unsigned getEncodedDLLStorageClass(const GlobalValue &GV) {
1190   switch (GV.getDLLStorageClass()) {
1191   case GlobalValue::DefaultStorageClass:   return 0;
1192   case GlobalValue::DLLImportStorageClass: return 1;
1193   case GlobalValue::DLLExportStorageClass: return 2;
1194   }
1195   llvm_unreachable("Invalid DLL storage class");
1196 }
1197 
1198 static unsigned getEncodedThreadLocalMode(const GlobalValue &GV) {
1199   switch (GV.getThreadLocalMode()) {
1200     case GlobalVariable::NotThreadLocal:         return 0;
1201     case GlobalVariable::GeneralDynamicTLSModel: return 1;
1202     case GlobalVariable::LocalDynamicTLSModel:   return 2;
1203     case GlobalVariable::InitialExecTLSModel:    return 3;
1204     case GlobalVariable::LocalExecTLSModel:      return 4;
1205   }
1206   llvm_unreachable("Invalid TLS model");
1207 }
1208 
1209 static unsigned getEncodedComdatSelectionKind(const Comdat &C) {
1210   switch (C.getSelectionKind()) {
1211   case Comdat::Any:
1212     return bitc::COMDAT_SELECTION_KIND_ANY;
1213   case Comdat::ExactMatch:
1214     return bitc::COMDAT_SELECTION_KIND_EXACT_MATCH;
1215   case Comdat::Largest:
1216     return bitc::COMDAT_SELECTION_KIND_LARGEST;
1217   case Comdat::NoDeduplicate:
1218     return bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES;
1219   case Comdat::SameSize:
1220     return bitc::COMDAT_SELECTION_KIND_SAME_SIZE;
1221   }
1222   llvm_unreachable("Invalid selection kind");
1223 }
1224 
1225 static unsigned getEncodedUnnamedAddr(const GlobalValue &GV) {
1226   switch (GV.getUnnamedAddr()) {
1227   case GlobalValue::UnnamedAddr::None:   return 0;
1228   case GlobalValue::UnnamedAddr::Local:  return 2;
1229   case GlobalValue::UnnamedAddr::Global: return 1;
1230   }
1231   llvm_unreachable("Invalid unnamed_addr");
1232 }
1233 
1234 size_t ModuleBitcodeWriter::addToStrtab(StringRef Str) {
1235   if (GenerateHash)
1236     Hasher.update(Str);
1237   return StrtabBuilder.add(Str);
1238 }
1239 
1240 void ModuleBitcodeWriter::writeComdats() {
1241   SmallVector<unsigned, 64> Vals;
1242   for (const Comdat *C : VE.getComdats()) {
1243     // COMDAT: [strtab offset, strtab size, selection_kind]
1244     Vals.push_back(addToStrtab(C->getName()));
1245     Vals.push_back(C->getName().size());
1246     Vals.push_back(getEncodedComdatSelectionKind(*C));
1247     Stream.EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
1248     Vals.clear();
1249   }
1250 }
1251 
1252 /// Write a record that will eventually hold the word offset of the
1253 /// module-level VST. For now the offset is 0, which will be backpatched
1254 /// after the real VST is written. Saves the bit offset to backpatch.
1255 void ModuleBitcodeWriter::writeValueSymbolTableForwardDecl() {
1256   // Write a placeholder value in for the offset of the real VST,
1257   // which is written after the function blocks so that it can include
1258   // the offset of each function. The placeholder offset will be
1259   // updated when the real VST is written.
1260   auto Abbv = std::make_shared<BitCodeAbbrev>();
1261   Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_VSTOFFSET));
1262   // Blocks are 32-bit aligned, so we can use a 32-bit word offset to
1263   // hold the real VST offset. Must use fixed instead of VBR as we don't
1264   // know how many VBR chunks to reserve ahead of time.
1265   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
1266   unsigned VSTOffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1267 
1268   // Emit the placeholder
1269   uint64_t Vals[] = {bitc::MODULE_CODE_VSTOFFSET, 0};
1270   Stream.EmitRecordWithAbbrev(VSTOffsetAbbrev, Vals);
1271 
1272   // Compute and save the bit offset to the placeholder, which will be
1273   // patched when the real VST is written. We can simply subtract the 32-bit
1274   // fixed size from the current bit number to get the location to backpatch.
1275   VSTOffsetPlaceholder = Stream.GetCurrentBitNo() - 32;
1276 }
1277 
1278 enum StringEncoding { SE_Char6, SE_Fixed7, SE_Fixed8 };
1279 
1280 /// Determine the encoding to use for the given string name and length.
1281 static StringEncoding getStringEncoding(StringRef Str) {
1282   bool isChar6 = true;
1283   for (char C : Str) {
1284     if (isChar6)
1285       isChar6 = BitCodeAbbrevOp::isChar6(C);
1286     if ((unsigned char)C & 128)
1287       // don't bother scanning the rest.
1288       return SE_Fixed8;
1289   }
1290   if (isChar6)
1291     return SE_Char6;
1292   return SE_Fixed7;
1293 }
1294 
1295 static_assert(sizeof(GlobalValue::SanitizerMetadata) <= sizeof(unsigned),
1296               "Sanitizer Metadata is too large for naive serialization.");
1297 static unsigned
1298 serializeSanitizerMetadata(const GlobalValue::SanitizerMetadata &Meta) {
1299   return Meta.NoAddress | (Meta.NoHWAddress << 1) |
1300          (Meta.Memtag << 2) | (Meta.IsDynInit << 3);
1301 }
1302 
1303 /// Emit top-level description of module, including target triple, inline asm,
1304 /// descriptors for global variables, and function prototype info.
1305 /// Returns the bit offset to backpatch with the location of the real VST.
1306 void ModuleBitcodeWriter::writeModuleInfo() {
1307   // Emit various pieces of data attached to a module.
1308   if (!M.getTargetTriple().empty())
1309     writeStringRecord(Stream, bitc::MODULE_CODE_TRIPLE, M.getTargetTriple(),
1310                       0 /*TODO*/);
1311   const std::string &DL = M.getDataLayoutStr();
1312   if (!DL.empty())
1313     writeStringRecord(Stream, bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/);
1314   if (!M.getModuleInlineAsm().empty())
1315     writeStringRecord(Stream, bitc::MODULE_CODE_ASM, M.getModuleInlineAsm(),
1316                       0 /*TODO*/);
1317 
1318   // Emit information about sections and GC, computing how many there are. Also
1319   // compute the maximum alignment value.
1320   std::map<std::string, unsigned> SectionMap;
1321   std::map<std::string, unsigned> GCMap;
1322   MaybeAlign MaxAlignment;
1323   unsigned MaxGlobalType = 0;
1324   const auto UpdateMaxAlignment = [&MaxAlignment](const MaybeAlign A) {
1325     if (A)
1326       MaxAlignment = !MaxAlignment ? *A : std::max(*MaxAlignment, *A);
1327   };
1328   for (const GlobalVariable &GV : M.globals()) {
1329     UpdateMaxAlignment(GV.getAlign());
1330     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getValueType()));
1331     if (GV.hasSection()) {
1332       // Give section names unique ID's.
1333       unsigned &Entry = SectionMap[std::string(GV.getSection())];
1334       if (!Entry) {
1335         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
1336                           0 /*TODO*/);
1337         Entry = SectionMap.size();
1338       }
1339     }
1340   }
1341   for (const Function &F : M) {
1342     UpdateMaxAlignment(F.getAlign());
1343     if (F.hasSection()) {
1344       // Give section names unique ID's.
1345       unsigned &Entry = SectionMap[std::string(F.getSection())];
1346       if (!Entry) {
1347         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
1348                           0 /*TODO*/);
1349         Entry = SectionMap.size();
1350       }
1351     }
1352     if (F.hasGC()) {
1353       // Same for GC names.
1354       unsigned &Entry = GCMap[F.getGC()];
1355       if (!Entry) {
1356         writeStringRecord(Stream, bitc::MODULE_CODE_GCNAME, F.getGC(),
1357                           0 /*TODO*/);
1358         Entry = GCMap.size();
1359       }
1360     }
1361   }
1362 
1363   // Emit abbrev for globals, now that we know # sections and max alignment.
1364   unsigned SimpleGVarAbbrev = 0;
1365   if (!M.global_empty()) {
1366     // Add an abbrev for common globals with no visibility or thread localness.
1367     auto Abbv = std::make_shared<BitCodeAbbrev>();
1368     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
1369     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1370     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1371     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1372                               Log2_32_Ceil(MaxGlobalType+1)));
1373     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddrSpace << 2
1374                                                            //| explicitType << 1
1375                                                            //| constant
1376     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Initializer.
1377     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // Linkage.
1378     if (!MaxAlignment)                                     // Alignment.
1379       Abbv->Add(BitCodeAbbrevOp(0));
1380     else {
1381       unsigned MaxEncAlignment = getEncodedAlign(MaxAlignment);
1382       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1383                                Log2_32_Ceil(MaxEncAlignment+1)));
1384     }
1385     if (SectionMap.empty())                                    // Section.
1386       Abbv->Add(BitCodeAbbrevOp(0));
1387     else
1388       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1389                                Log2_32_Ceil(SectionMap.size()+1)));
1390     // Don't bother emitting vis + thread local.
1391     SimpleGVarAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1392   }
1393 
1394   SmallVector<unsigned, 64> Vals;
1395   // Emit the module's source file name.
1396   {
1397     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
1398     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
1399     if (Bits == SE_Char6)
1400       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
1401     else if (Bits == SE_Fixed7)
1402       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
1403 
1404     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
1405     auto Abbv = std::make_shared<BitCodeAbbrev>();
1406     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
1407     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1408     Abbv->Add(AbbrevOpToUse);
1409     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1410 
1411     for (const auto P : M.getSourceFileName())
1412       Vals.push_back((unsigned char)P);
1413 
1414     // Emit the finished record.
1415     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
1416     Vals.clear();
1417   }
1418 
1419   // Emit the global variable information.
1420   for (const GlobalVariable &GV : M.globals()) {
1421     unsigned AbbrevToUse = 0;
1422 
1423     // GLOBALVAR: [strtab offset, strtab size, type, isconst, initid,
1424     //             linkage, alignment, section, visibility, threadlocal,
1425     //             unnamed_addr, externally_initialized, dllstorageclass,
1426     //             comdat, attributes, DSO_Local, GlobalSanitizer, code_model]
1427     Vals.push_back(addToStrtab(GV.getName()));
1428     Vals.push_back(GV.getName().size());
1429     Vals.push_back(VE.getTypeID(GV.getValueType()));
1430     Vals.push_back(GV.getType()->getAddressSpace() << 2 | 2 | GV.isConstant());
1431     Vals.push_back(GV.isDeclaration() ? 0 :
1432                    (VE.getValueID(GV.getInitializer()) + 1));
1433     Vals.push_back(getEncodedLinkage(GV));
1434     Vals.push_back(getEncodedAlign(GV.getAlign()));
1435     Vals.push_back(GV.hasSection() ? SectionMap[std::string(GV.getSection())]
1436                                    : 0);
1437     if (GV.isThreadLocal() ||
1438         GV.getVisibility() != GlobalValue::DefaultVisibility ||
1439         GV.getUnnamedAddr() != GlobalValue::UnnamedAddr::None ||
1440         GV.isExternallyInitialized() ||
1441         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
1442         GV.hasComdat() || GV.hasAttributes() || GV.isDSOLocal() ||
1443         GV.hasPartition() || GV.hasSanitizerMetadata() || GV.getCodeModel()) {
1444       Vals.push_back(getEncodedVisibility(GV));
1445       Vals.push_back(getEncodedThreadLocalMode(GV));
1446       Vals.push_back(getEncodedUnnamedAddr(GV));
1447       Vals.push_back(GV.isExternallyInitialized());
1448       Vals.push_back(getEncodedDLLStorageClass(GV));
1449       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
1450 
1451       auto AL = GV.getAttributesAsList(AttributeList::FunctionIndex);
1452       Vals.push_back(VE.getAttributeListID(AL));
1453 
1454       Vals.push_back(GV.isDSOLocal());
1455       Vals.push_back(addToStrtab(GV.getPartition()));
1456       Vals.push_back(GV.getPartition().size());
1457 
1458       Vals.push_back((GV.hasSanitizerMetadata() ? serializeSanitizerMetadata(
1459                                                       GV.getSanitizerMetadata())
1460                                                 : 0));
1461       Vals.push_back(GV.getCodeModelRaw());
1462     } else {
1463       AbbrevToUse = SimpleGVarAbbrev;
1464     }
1465 
1466     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
1467     Vals.clear();
1468   }
1469 
1470   // Emit the function proto information.
1471   for (const Function &F : M) {
1472     // FUNCTION:  [strtab offset, strtab size, type, callingconv, isproto,
1473     //             linkage, paramattrs, alignment, section, visibility, gc,
1474     //             unnamed_addr, prologuedata, dllstorageclass, comdat,
1475     //             prefixdata, personalityfn, DSO_Local, addrspace]
1476     Vals.push_back(addToStrtab(F.getName()));
1477     Vals.push_back(F.getName().size());
1478     Vals.push_back(VE.getTypeID(F.getFunctionType()));
1479     Vals.push_back(F.getCallingConv());
1480     Vals.push_back(F.isDeclaration());
1481     Vals.push_back(getEncodedLinkage(F));
1482     Vals.push_back(VE.getAttributeListID(F.getAttributes()));
1483     Vals.push_back(getEncodedAlign(F.getAlign()));
1484     Vals.push_back(F.hasSection() ? SectionMap[std::string(F.getSection())]
1485                                   : 0);
1486     Vals.push_back(getEncodedVisibility(F));
1487     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
1488     Vals.push_back(getEncodedUnnamedAddr(F));
1489     Vals.push_back(F.hasPrologueData() ? (VE.getValueID(F.getPrologueData()) + 1)
1490                                        : 0);
1491     Vals.push_back(getEncodedDLLStorageClass(F));
1492     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
1493     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
1494                                      : 0);
1495     Vals.push_back(
1496         F.hasPersonalityFn() ? (VE.getValueID(F.getPersonalityFn()) + 1) : 0);
1497 
1498     Vals.push_back(F.isDSOLocal());
1499     Vals.push_back(F.getAddressSpace());
1500     Vals.push_back(addToStrtab(F.getPartition()));
1501     Vals.push_back(F.getPartition().size());
1502 
1503     unsigned AbbrevToUse = 0;
1504     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
1505     Vals.clear();
1506   }
1507 
1508   // Emit the alias information.
1509   for (const GlobalAlias &A : M.aliases()) {
1510     // ALIAS: [strtab offset, strtab size, alias type, aliasee val#, linkage,
1511     //         visibility, dllstorageclass, threadlocal, unnamed_addr,
1512     //         DSO_Local]
1513     Vals.push_back(addToStrtab(A.getName()));
1514     Vals.push_back(A.getName().size());
1515     Vals.push_back(VE.getTypeID(A.getValueType()));
1516     Vals.push_back(A.getType()->getAddressSpace());
1517     Vals.push_back(VE.getValueID(A.getAliasee()));
1518     Vals.push_back(getEncodedLinkage(A));
1519     Vals.push_back(getEncodedVisibility(A));
1520     Vals.push_back(getEncodedDLLStorageClass(A));
1521     Vals.push_back(getEncodedThreadLocalMode(A));
1522     Vals.push_back(getEncodedUnnamedAddr(A));
1523     Vals.push_back(A.isDSOLocal());
1524     Vals.push_back(addToStrtab(A.getPartition()));
1525     Vals.push_back(A.getPartition().size());
1526 
1527     unsigned AbbrevToUse = 0;
1528     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
1529     Vals.clear();
1530   }
1531 
1532   // Emit the ifunc information.
1533   for (const GlobalIFunc &I : M.ifuncs()) {
1534     // IFUNC: [strtab offset, strtab size, ifunc type, address space, resolver
1535     //         val#, linkage, visibility, DSO_Local]
1536     Vals.push_back(addToStrtab(I.getName()));
1537     Vals.push_back(I.getName().size());
1538     Vals.push_back(VE.getTypeID(I.getValueType()));
1539     Vals.push_back(I.getType()->getAddressSpace());
1540     Vals.push_back(VE.getValueID(I.getResolver()));
1541     Vals.push_back(getEncodedLinkage(I));
1542     Vals.push_back(getEncodedVisibility(I));
1543     Vals.push_back(I.isDSOLocal());
1544     Vals.push_back(addToStrtab(I.getPartition()));
1545     Vals.push_back(I.getPartition().size());
1546     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
1547     Vals.clear();
1548   }
1549 
1550   writeValueSymbolTableForwardDecl();
1551 }
1552 
1553 static uint64_t getOptimizationFlags(const Value *V) {
1554   uint64_t Flags = 0;
1555 
1556   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
1557     if (OBO->hasNoSignedWrap())
1558       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
1559     if (OBO->hasNoUnsignedWrap())
1560       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
1561   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
1562     if (PEO->isExact())
1563       Flags |= 1 << bitc::PEO_EXACT;
1564   } else if (const auto *PDI = dyn_cast<PossiblyDisjointInst>(V)) {
1565     if (PDI->isDisjoint())
1566       Flags |= 1 << bitc::PDI_DISJOINT;
1567   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
1568     if (FPMO->hasAllowReassoc())
1569       Flags |= bitc::AllowReassoc;
1570     if (FPMO->hasNoNaNs())
1571       Flags |= bitc::NoNaNs;
1572     if (FPMO->hasNoInfs())
1573       Flags |= bitc::NoInfs;
1574     if (FPMO->hasNoSignedZeros())
1575       Flags |= bitc::NoSignedZeros;
1576     if (FPMO->hasAllowReciprocal())
1577       Flags |= bitc::AllowReciprocal;
1578     if (FPMO->hasAllowContract())
1579       Flags |= bitc::AllowContract;
1580     if (FPMO->hasApproxFunc())
1581       Flags |= bitc::ApproxFunc;
1582   } else if (const auto *NNI = dyn_cast<PossiblyNonNegInst>(V)) {
1583     if (NNI->hasNonNeg())
1584       Flags |= 1 << bitc::PNNI_NON_NEG;
1585   }
1586 
1587   return Flags;
1588 }
1589 
1590 void ModuleBitcodeWriter::writeValueAsMetadata(
1591     const ValueAsMetadata *MD, SmallVectorImpl<uint64_t> &Record) {
1592   // Mimic an MDNode with a value as one operand.
1593   Value *V = MD->getValue();
1594   Record.push_back(VE.getTypeID(V->getType()));
1595   Record.push_back(VE.getValueID(V));
1596   Stream.EmitRecord(bitc::METADATA_VALUE, Record, 0);
1597   Record.clear();
1598 }
1599 
1600 void ModuleBitcodeWriter::writeMDTuple(const MDTuple *N,
1601                                        SmallVectorImpl<uint64_t> &Record,
1602                                        unsigned Abbrev) {
1603   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
1604     Metadata *MD = N->getOperand(i);
1605     assert(!(MD && isa<LocalAsMetadata>(MD)) &&
1606            "Unexpected function-local metadata");
1607     Record.push_back(VE.getMetadataOrNullID(MD));
1608   }
1609   Stream.EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
1610                                     : bitc::METADATA_NODE,
1611                     Record, Abbrev);
1612   Record.clear();
1613 }
1614 
1615 unsigned ModuleBitcodeWriter::createDILocationAbbrev() {
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_LOCATION));
1620   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1621   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1622   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1623   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1624   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1625   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1626   return Stream.EmitAbbrev(std::move(Abbv));
1627 }
1628 
1629 void ModuleBitcodeWriter::writeDILocation(const DILocation *N,
1630                                           SmallVectorImpl<uint64_t> &Record,
1631                                           unsigned &Abbrev) {
1632   if (!Abbrev)
1633     Abbrev = createDILocationAbbrev();
1634 
1635   Record.push_back(N->isDistinct());
1636   Record.push_back(N->getLine());
1637   Record.push_back(N->getColumn());
1638   Record.push_back(VE.getMetadataID(N->getScope()));
1639   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
1640   Record.push_back(N->isImplicitCode());
1641 
1642   Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
1643   Record.clear();
1644 }
1645 
1646 unsigned ModuleBitcodeWriter::createGenericDINodeAbbrev() {
1647   // Assume the column is usually under 128, and always output the inlined-at
1648   // location (it's never more expensive than building an array size 1).
1649   auto Abbv = std::make_shared<BitCodeAbbrev>();
1650   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
1651   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1652   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1653   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1654   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1655   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1656   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1657   return Stream.EmitAbbrev(std::move(Abbv));
1658 }
1659 
1660 void ModuleBitcodeWriter::writeGenericDINode(const GenericDINode *N,
1661                                              SmallVectorImpl<uint64_t> &Record,
1662                                              unsigned &Abbrev) {
1663   if (!Abbrev)
1664     Abbrev = createGenericDINodeAbbrev();
1665 
1666   Record.push_back(N->isDistinct());
1667   Record.push_back(N->getTag());
1668   Record.push_back(0); // Per-tag version field; unused for now.
1669 
1670   for (auto &I : N->operands())
1671     Record.push_back(VE.getMetadataOrNullID(I));
1672 
1673   Stream.EmitRecord(bitc::METADATA_GENERIC_DEBUG, Record, Abbrev);
1674   Record.clear();
1675 }
1676 
1677 void ModuleBitcodeWriter::writeDISubrange(const DISubrange *N,
1678                                           SmallVectorImpl<uint64_t> &Record,
1679                                           unsigned Abbrev) {
1680   const uint64_t Version = 2 << 1;
1681   Record.push_back((uint64_t)N->isDistinct() | Version);
1682   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1683   Record.push_back(VE.getMetadataOrNullID(N->getRawLowerBound()));
1684   Record.push_back(VE.getMetadataOrNullID(N->getRawUpperBound()));
1685   Record.push_back(VE.getMetadataOrNullID(N->getRawStride()));
1686 
1687   Stream.EmitRecord(bitc::METADATA_SUBRANGE, Record, Abbrev);
1688   Record.clear();
1689 }
1690 
1691 void ModuleBitcodeWriter::writeDIGenericSubrange(
1692     const DIGenericSubrange *N, SmallVectorImpl<uint64_t> &Record,
1693     unsigned Abbrev) {
1694   Record.push_back((uint64_t)N->isDistinct());
1695   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1696   Record.push_back(VE.getMetadataOrNullID(N->getRawLowerBound()));
1697   Record.push_back(VE.getMetadataOrNullID(N->getRawUpperBound()));
1698   Record.push_back(VE.getMetadataOrNullID(N->getRawStride()));
1699 
1700   Stream.EmitRecord(bitc::METADATA_GENERIC_SUBRANGE, Record, Abbrev);
1701   Record.clear();
1702 }
1703 
1704 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
1705   if ((int64_t)V >= 0)
1706     Vals.push_back(V << 1);
1707   else
1708     Vals.push_back((-V << 1) | 1);
1709 }
1710 
1711 static void emitWideAPInt(SmallVectorImpl<uint64_t> &Vals, const APInt &A) {
1712   // We have an arbitrary precision integer value to write whose
1713   // bit width is > 64. However, in canonical unsigned integer
1714   // format it is likely that the high bits are going to be zero.
1715   // So, we only write the number of active words.
1716   unsigned NumWords = A.getActiveWords();
1717   const uint64_t *RawData = A.getRawData();
1718   for (unsigned i = 0; i < NumWords; i++)
1719     emitSignedInt64(Vals, RawData[i]);
1720 }
1721 
1722 void ModuleBitcodeWriter::writeDIEnumerator(const DIEnumerator *N,
1723                                             SmallVectorImpl<uint64_t> &Record,
1724                                             unsigned Abbrev) {
1725   const uint64_t IsBigInt = 1 << 2;
1726   Record.push_back(IsBigInt | (N->isUnsigned() << 1) | N->isDistinct());
1727   Record.push_back(N->getValue().getBitWidth());
1728   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1729   emitWideAPInt(Record, N->getValue());
1730 
1731   Stream.EmitRecord(bitc::METADATA_ENUMERATOR, Record, Abbrev);
1732   Record.clear();
1733 }
1734 
1735 void ModuleBitcodeWriter::writeDIBasicType(const DIBasicType *N,
1736                                            SmallVectorImpl<uint64_t> &Record,
1737                                            unsigned Abbrev) {
1738   Record.push_back(N->isDistinct());
1739   Record.push_back(N->getTag());
1740   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1741   Record.push_back(N->getSizeInBits());
1742   Record.push_back(N->getAlignInBits());
1743   Record.push_back(N->getEncoding());
1744   Record.push_back(N->getFlags());
1745 
1746   Stream.EmitRecord(bitc::METADATA_BASIC_TYPE, Record, Abbrev);
1747   Record.clear();
1748 }
1749 
1750 void ModuleBitcodeWriter::writeDIStringType(const DIStringType *N,
1751                                             SmallVectorImpl<uint64_t> &Record,
1752                                             unsigned Abbrev) {
1753   Record.push_back(N->isDistinct());
1754   Record.push_back(N->getTag());
1755   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1756   Record.push_back(VE.getMetadataOrNullID(N->getStringLength()));
1757   Record.push_back(VE.getMetadataOrNullID(N->getStringLengthExp()));
1758   Record.push_back(VE.getMetadataOrNullID(N->getStringLocationExp()));
1759   Record.push_back(N->getSizeInBits());
1760   Record.push_back(N->getAlignInBits());
1761   Record.push_back(N->getEncoding());
1762 
1763   Stream.EmitRecord(bitc::METADATA_STRING_TYPE, Record, Abbrev);
1764   Record.clear();
1765 }
1766 
1767 void ModuleBitcodeWriter::writeDIDerivedType(const DIDerivedType *N,
1768                                              SmallVectorImpl<uint64_t> &Record,
1769                                              unsigned Abbrev) {
1770   Record.push_back(N->isDistinct());
1771   Record.push_back(N->getTag());
1772   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1773   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1774   Record.push_back(N->getLine());
1775   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1776   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1777   Record.push_back(N->getSizeInBits());
1778   Record.push_back(N->getAlignInBits());
1779   Record.push_back(N->getOffsetInBits());
1780   Record.push_back(N->getFlags());
1781   Record.push_back(VE.getMetadataOrNullID(N->getExtraData()));
1782 
1783   // DWARF address space is encoded as N->getDWARFAddressSpace() + 1. 0 means
1784   // that there is no DWARF address space associated with DIDerivedType.
1785   if (const auto &DWARFAddressSpace = N->getDWARFAddressSpace())
1786     Record.push_back(*DWARFAddressSpace + 1);
1787   else
1788     Record.push_back(0);
1789 
1790   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1791 
1792   Stream.EmitRecord(bitc::METADATA_DERIVED_TYPE, Record, Abbrev);
1793   Record.clear();
1794 }
1795 
1796 void ModuleBitcodeWriter::writeDICompositeType(
1797     const DICompositeType *N, SmallVectorImpl<uint64_t> &Record,
1798     unsigned Abbrev) {
1799   const unsigned IsNotUsedInOldTypeRef = 0x2;
1800   Record.push_back(IsNotUsedInOldTypeRef | (unsigned)N->isDistinct());
1801   Record.push_back(N->getTag());
1802   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1803   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1804   Record.push_back(N->getLine());
1805   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1806   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1807   Record.push_back(N->getSizeInBits());
1808   Record.push_back(N->getAlignInBits());
1809   Record.push_back(N->getOffsetInBits());
1810   Record.push_back(N->getFlags());
1811   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1812   Record.push_back(N->getRuntimeLang());
1813   Record.push_back(VE.getMetadataOrNullID(N->getVTableHolder()));
1814   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1815   Record.push_back(VE.getMetadataOrNullID(N->getRawIdentifier()));
1816   Record.push_back(VE.getMetadataOrNullID(N->getDiscriminator()));
1817   Record.push_back(VE.getMetadataOrNullID(N->getRawDataLocation()));
1818   Record.push_back(VE.getMetadataOrNullID(N->getRawAssociated()));
1819   Record.push_back(VE.getMetadataOrNullID(N->getRawAllocated()));
1820   Record.push_back(VE.getMetadataOrNullID(N->getRawRank()));
1821   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1822 
1823   Stream.EmitRecord(bitc::METADATA_COMPOSITE_TYPE, Record, Abbrev);
1824   Record.clear();
1825 }
1826 
1827 void ModuleBitcodeWriter::writeDISubroutineType(
1828     const DISubroutineType *N, SmallVectorImpl<uint64_t> &Record,
1829     unsigned Abbrev) {
1830   const unsigned HasNoOldTypeRefs = 0x2;
1831   Record.push_back(HasNoOldTypeRefs | (unsigned)N->isDistinct());
1832   Record.push_back(N->getFlags());
1833   Record.push_back(VE.getMetadataOrNullID(N->getTypeArray().get()));
1834   Record.push_back(N->getCC());
1835 
1836   Stream.EmitRecord(bitc::METADATA_SUBROUTINE_TYPE, Record, Abbrev);
1837   Record.clear();
1838 }
1839 
1840 void ModuleBitcodeWriter::writeDIFile(const DIFile *N,
1841                                       SmallVectorImpl<uint64_t> &Record,
1842                                       unsigned Abbrev) {
1843   Record.push_back(N->isDistinct());
1844   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
1845   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
1846   if (N->getRawChecksum()) {
1847     Record.push_back(N->getRawChecksum()->Kind);
1848     Record.push_back(VE.getMetadataOrNullID(N->getRawChecksum()->Value));
1849   } else {
1850     // Maintain backwards compatibility with the old internal representation of
1851     // CSK_None in ChecksumKind by writing nulls here when Checksum is None.
1852     Record.push_back(0);
1853     Record.push_back(VE.getMetadataOrNullID(nullptr));
1854   }
1855   auto Source = N->getRawSource();
1856   if (Source)
1857     Record.push_back(VE.getMetadataOrNullID(Source));
1858 
1859   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
1860   Record.clear();
1861 }
1862 
1863 void ModuleBitcodeWriter::writeDICompileUnit(const DICompileUnit *N,
1864                                              SmallVectorImpl<uint64_t> &Record,
1865                                              unsigned Abbrev) {
1866   assert(N->isDistinct() && "Expected distinct compile units");
1867   Record.push_back(/* IsDistinct */ true);
1868   Record.push_back(N->getSourceLanguage());
1869   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1870   Record.push_back(VE.getMetadataOrNullID(N->getRawProducer()));
1871   Record.push_back(N->isOptimized());
1872   Record.push_back(VE.getMetadataOrNullID(N->getRawFlags()));
1873   Record.push_back(N->getRuntimeVersion());
1874   Record.push_back(VE.getMetadataOrNullID(N->getRawSplitDebugFilename()));
1875   Record.push_back(N->getEmissionKind());
1876   Record.push_back(VE.getMetadataOrNullID(N->getEnumTypes().get()));
1877   Record.push_back(VE.getMetadataOrNullID(N->getRetainedTypes().get()));
1878   Record.push_back(/* subprograms */ 0);
1879   Record.push_back(VE.getMetadataOrNullID(N->getGlobalVariables().get()));
1880   Record.push_back(VE.getMetadataOrNullID(N->getImportedEntities().get()));
1881   Record.push_back(N->getDWOId());
1882   Record.push_back(VE.getMetadataOrNullID(N->getMacros().get()));
1883   Record.push_back(N->getSplitDebugInlining());
1884   Record.push_back(N->getDebugInfoForProfiling());
1885   Record.push_back((unsigned)N->getNameTableKind());
1886   Record.push_back(N->getRangesBaseAddress());
1887   Record.push_back(VE.getMetadataOrNullID(N->getRawSysRoot()));
1888   Record.push_back(VE.getMetadataOrNullID(N->getRawSDK()));
1889 
1890   Stream.EmitRecord(bitc::METADATA_COMPILE_UNIT, Record, Abbrev);
1891   Record.clear();
1892 }
1893 
1894 void ModuleBitcodeWriter::writeDISubprogram(const DISubprogram *N,
1895                                             SmallVectorImpl<uint64_t> &Record,
1896                                             unsigned Abbrev) {
1897   const uint64_t HasUnitFlag = 1 << 1;
1898   const uint64_t HasSPFlagsFlag = 1 << 2;
1899   Record.push_back(uint64_t(N->isDistinct()) | HasUnitFlag | HasSPFlagsFlag);
1900   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1901   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1902   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1903   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1904   Record.push_back(N->getLine());
1905   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1906   Record.push_back(N->getScopeLine());
1907   Record.push_back(VE.getMetadataOrNullID(N->getContainingType()));
1908   Record.push_back(N->getSPFlags());
1909   Record.push_back(N->getVirtualIndex());
1910   Record.push_back(N->getFlags());
1911   Record.push_back(VE.getMetadataOrNullID(N->getRawUnit()));
1912   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1913   Record.push_back(VE.getMetadataOrNullID(N->getDeclaration()));
1914   Record.push_back(VE.getMetadataOrNullID(N->getRetainedNodes().get()));
1915   Record.push_back(N->getThisAdjustment());
1916   Record.push_back(VE.getMetadataOrNullID(N->getThrownTypes().get()));
1917   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1918   Record.push_back(VE.getMetadataOrNullID(N->getRawTargetFuncName()));
1919 
1920   Stream.EmitRecord(bitc::METADATA_SUBPROGRAM, Record, Abbrev);
1921   Record.clear();
1922 }
1923 
1924 void ModuleBitcodeWriter::writeDILexicalBlock(const DILexicalBlock *N,
1925                                               SmallVectorImpl<uint64_t> &Record,
1926                                               unsigned Abbrev) {
1927   Record.push_back(N->isDistinct());
1928   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1929   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1930   Record.push_back(N->getLine());
1931   Record.push_back(N->getColumn());
1932 
1933   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK, Record, Abbrev);
1934   Record.clear();
1935 }
1936 
1937 void ModuleBitcodeWriter::writeDILexicalBlockFile(
1938     const DILexicalBlockFile *N, SmallVectorImpl<uint64_t> &Record,
1939     unsigned Abbrev) {
1940   Record.push_back(N->isDistinct());
1941   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1942   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1943   Record.push_back(N->getDiscriminator());
1944 
1945   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK_FILE, Record, Abbrev);
1946   Record.clear();
1947 }
1948 
1949 void ModuleBitcodeWriter::writeDICommonBlock(const DICommonBlock *N,
1950                                              SmallVectorImpl<uint64_t> &Record,
1951                                              unsigned Abbrev) {
1952   Record.push_back(N->isDistinct());
1953   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1954   Record.push_back(VE.getMetadataOrNullID(N->getDecl()));
1955   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1956   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1957   Record.push_back(N->getLineNo());
1958 
1959   Stream.EmitRecord(bitc::METADATA_COMMON_BLOCK, Record, Abbrev);
1960   Record.clear();
1961 }
1962 
1963 void ModuleBitcodeWriter::writeDINamespace(const DINamespace *N,
1964                                            SmallVectorImpl<uint64_t> &Record,
1965                                            unsigned Abbrev) {
1966   Record.push_back(N->isDistinct() | N->getExportSymbols() << 1);
1967   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1968   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1969 
1970   Stream.EmitRecord(bitc::METADATA_NAMESPACE, Record, Abbrev);
1971   Record.clear();
1972 }
1973 
1974 void ModuleBitcodeWriter::writeDIMacro(const DIMacro *N,
1975                                        SmallVectorImpl<uint64_t> &Record,
1976                                        unsigned Abbrev) {
1977   Record.push_back(N->isDistinct());
1978   Record.push_back(N->getMacinfoType());
1979   Record.push_back(N->getLine());
1980   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1981   Record.push_back(VE.getMetadataOrNullID(N->getRawValue()));
1982 
1983   Stream.EmitRecord(bitc::METADATA_MACRO, Record, Abbrev);
1984   Record.clear();
1985 }
1986 
1987 void ModuleBitcodeWriter::writeDIMacroFile(const DIMacroFile *N,
1988                                            SmallVectorImpl<uint64_t> &Record,
1989                                            unsigned Abbrev) {
1990   Record.push_back(N->isDistinct());
1991   Record.push_back(N->getMacinfoType());
1992   Record.push_back(N->getLine());
1993   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1994   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1995 
1996   Stream.EmitRecord(bitc::METADATA_MACRO_FILE, Record, Abbrev);
1997   Record.clear();
1998 }
1999 
2000 void ModuleBitcodeWriter::writeDIArgList(const DIArgList *N,
2001                                          SmallVectorImpl<uint64_t> &Record) {
2002   Record.reserve(N->getArgs().size());
2003   for (ValueAsMetadata *MD : N->getArgs())
2004     Record.push_back(VE.getMetadataID(MD));
2005 
2006   Stream.EmitRecord(bitc::METADATA_ARG_LIST, Record);
2007   Record.clear();
2008 }
2009 
2010 void ModuleBitcodeWriter::writeDIModule(const DIModule *N,
2011                                         SmallVectorImpl<uint64_t> &Record,
2012                                         unsigned Abbrev) {
2013   Record.push_back(N->isDistinct());
2014   for (auto &I : N->operands())
2015     Record.push_back(VE.getMetadataOrNullID(I));
2016   Record.push_back(N->getLineNo());
2017   Record.push_back(N->getIsDecl());
2018 
2019   Stream.EmitRecord(bitc::METADATA_MODULE, Record, Abbrev);
2020   Record.clear();
2021 }
2022 
2023 void ModuleBitcodeWriter::writeDIAssignID(const DIAssignID *N,
2024                                           SmallVectorImpl<uint64_t> &Record,
2025                                           unsigned Abbrev) {
2026   // There are no arguments for this metadata type.
2027   Record.push_back(N->isDistinct());
2028   Stream.EmitRecord(bitc::METADATA_ASSIGN_ID, Record, Abbrev);
2029   Record.clear();
2030 }
2031 
2032 void ModuleBitcodeWriter::writeDITemplateTypeParameter(
2033     const DITemplateTypeParameter *N, SmallVectorImpl<uint64_t> &Record,
2034     unsigned Abbrev) {
2035   Record.push_back(N->isDistinct());
2036   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2037   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2038   Record.push_back(N->isDefault());
2039 
2040   Stream.EmitRecord(bitc::METADATA_TEMPLATE_TYPE, Record, Abbrev);
2041   Record.clear();
2042 }
2043 
2044 void ModuleBitcodeWriter::writeDITemplateValueParameter(
2045     const DITemplateValueParameter *N, SmallVectorImpl<uint64_t> &Record,
2046     unsigned Abbrev) {
2047   Record.push_back(N->isDistinct());
2048   Record.push_back(N->getTag());
2049   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2050   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2051   Record.push_back(N->isDefault());
2052   Record.push_back(VE.getMetadataOrNullID(N->getValue()));
2053 
2054   Stream.EmitRecord(bitc::METADATA_TEMPLATE_VALUE, Record, Abbrev);
2055   Record.clear();
2056 }
2057 
2058 void ModuleBitcodeWriter::writeDIGlobalVariable(
2059     const DIGlobalVariable *N, SmallVectorImpl<uint64_t> &Record,
2060     unsigned Abbrev) {
2061   const uint64_t Version = 2 << 1;
2062   Record.push_back((uint64_t)N->isDistinct() | Version);
2063   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2064   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2065   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
2066   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2067   Record.push_back(N->getLine());
2068   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2069   Record.push_back(N->isLocalToUnit());
2070   Record.push_back(N->isDefinition());
2071   Record.push_back(VE.getMetadataOrNullID(N->getStaticDataMemberDeclaration()));
2072   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams()));
2073   Record.push_back(N->getAlignInBits());
2074   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
2075 
2076   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR, Record, Abbrev);
2077   Record.clear();
2078 }
2079 
2080 void ModuleBitcodeWriter::writeDILocalVariable(
2081     const DILocalVariable *N, SmallVectorImpl<uint64_t> &Record,
2082     unsigned Abbrev) {
2083   // In order to support all possible bitcode formats in BitcodeReader we need
2084   // to distinguish the following cases:
2085   // 1) Record has no artificial tag (Record[1]),
2086   //   has no obsolete inlinedAt field (Record[9]).
2087   //   In this case Record size will be 8, HasAlignment flag is false.
2088   // 2) Record has artificial tag (Record[1]),
2089   //   has no obsolete inlignedAt field (Record[9]).
2090   //   In this case Record size will be 9, HasAlignment flag is false.
2091   // 3) Record has both artificial tag (Record[1]) and
2092   //   obsolete inlignedAt field (Record[9]).
2093   //   In this case Record size will be 10, HasAlignment flag is false.
2094   // 4) Record has neither artificial tag, nor inlignedAt field, but
2095   //   HasAlignment flag is true and Record[8] contains alignment value.
2096   const uint64_t HasAlignmentFlag = 1 << 1;
2097   Record.push_back((uint64_t)N->isDistinct() | HasAlignmentFlag);
2098   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2099   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2100   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2101   Record.push_back(N->getLine());
2102   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2103   Record.push_back(N->getArg());
2104   Record.push_back(N->getFlags());
2105   Record.push_back(N->getAlignInBits());
2106   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
2107 
2108   Stream.EmitRecord(bitc::METADATA_LOCAL_VAR, Record, Abbrev);
2109   Record.clear();
2110 }
2111 
2112 void ModuleBitcodeWriter::writeDILabel(
2113     const DILabel *N, SmallVectorImpl<uint64_t> &Record,
2114     unsigned Abbrev) {
2115   Record.push_back((uint64_t)N->isDistinct());
2116   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2117   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2118   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2119   Record.push_back(N->getLine());
2120 
2121   Stream.EmitRecord(bitc::METADATA_LABEL, Record, Abbrev);
2122   Record.clear();
2123 }
2124 
2125 void ModuleBitcodeWriter::writeDIExpression(const DIExpression *N,
2126                                             SmallVectorImpl<uint64_t> &Record,
2127                                             unsigned Abbrev) {
2128   Record.reserve(N->getElements().size() + 1);
2129   const uint64_t Version = 3 << 1;
2130   Record.push_back((uint64_t)N->isDistinct() | Version);
2131   Record.append(N->elements_begin(), N->elements_end());
2132 
2133   Stream.EmitRecord(bitc::METADATA_EXPRESSION, Record, Abbrev);
2134   Record.clear();
2135 }
2136 
2137 void ModuleBitcodeWriter::writeDIGlobalVariableExpression(
2138     const DIGlobalVariableExpression *N, SmallVectorImpl<uint64_t> &Record,
2139     unsigned Abbrev) {
2140   Record.push_back(N->isDistinct());
2141   Record.push_back(VE.getMetadataOrNullID(N->getVariable()));
2142   Record.push_back(VE.getMetadataOrNullID(N->getExpression()));
2143 
2144   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR_EXPR, Record, Abbrev);
2145   Record.clear();
2146 }
2147 
2148 void ModuleBitcodeWriter::writeDIObjCProperty(const DIObjCProperty *N,
2149                                               SmallVectorImpl<uint64_t> &Record,
2150                                               unsigned Abbrev) {
2151   Record.push_back(N->isDistinct());
2152   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2153   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2154   Record.push_back(N->getLine());
2155   Record.push_back(VE.getMetadataOrNullID(N->getRawSetterName()));
2156   Record.push_back(VE.getMetadataOrNullID(N->getRawGetterName()));
2157   Record.push_back(N->getAttributes());
2158   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2159 
2160   Stream.EmitRecord(bitc::METADATA_OBJC_PROPERTY, Record, Abbrev);
2161   Record.clear();
2162 }
2163 
2164 void ModuleBitcodeWriter::writeDIImportedEntity(
2165     const DIImportedEntity *N, SmallVectorImpl<uint64_t> &Record,
2166     unsigned Abbrev) {
2167   Record.push_back(N->isDistinct());
2168   Record.push_back(N->getTag());
2169   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2170   Record.push_back(VE.getMetadataOrNullID(N->getEntity()));
2171   Record.push_back(N->getLine());
2172   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2173   Record.push_back(VE.getMetadataOrNullID(N->getRawFile()));
2174   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
2175 
2176   Stream.EmitRecord(bitc::METADATA_IMPORTED_ENTITY, Record, Abbrev);
2177   Record.clear();
2178 }
2179 
2180 unsigned ModuleBitcodeWriter::createNamedMetadataAbbrev() {
2181   auto Abbv = std::make_shared<BitCodeAbbrev>();
2182   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
2183   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2184   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2185   return Stream.EmitAbbrev(std::move(Abbv));
2186 }
2187 
2188 void ModuleBitcodeWriter::writeNamedMetadata(
2189     SmallVectorImpl<uint64_t> &Record) {
2190   if (M.named_metadata_empty())
2191     return;
2192 
2193   unsigned Abbrev = createNamedMetadataAbbrev();
2194   for (const NamedMDNode &NMD : M.named_metadata()) {
2195     // Write name.
2196     StringRef Str = NMD.getName();
2197     Record.append(Str.bytes_begin(), Str.bytes_end());
2198     Stream.EmitRecord(bitc::METADATA_NAME, Record, Abbrev);
2199     Record.clear();
2200 
2201     // Write named metadata operands.
2202     for (const MDNode *N : NMD.operands())
2203       Record.push_back(VE.getMetadataID(N));
2204     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
2205     Record.clear();
2206   }
2207 }
2208 
2209 unsigned ModuleBitcodeWriter::createMetadataStringsAbbrev() {
2210   auto Abbv = std::make_shared<BitCodeAbbrev>();
2211   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRINGS));
2212   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // # of strings
2213   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // offset to chars
2214   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
2215   return Stream.EmitAbbrev(std::move(Abbv));
2216 }
2217 
2218 /// Write out a record for MDString.
2219 ///
2220 /// All the metadata strings in a metadata block are emitted in a single
2221 /// record.  The sizes and strings themselves are shoved into a blob.
2222 void ModuleBitcodeWriter::writeMetadataStrings(
2223     ArrayRef<const Metadata *> Strings, SmallVectorImpl<uint64_t> &Record) {
2224   if (Strings.empty())
2225     return;
2226 
2227   // Start the record with the number of strings.
2228   Record.push_back(bitc::METADATA_STRINGS);
2229   Record.push_back(Strings.size());
2230 
2231   // Emit the sizes of the strings in the blob.
2232   SmallString<256> Blob;
2233   {
2234     BitstreamWriter W(Blob);
2235     for (const Metadata *MD : Strings)
2236       W.EmitVBR(cast<MDString>(MD)->getLength(), 6);
2237     W.FlushToWord();
2238   }
2239 
2240   // Add the offset to the strings to the record.
2241   Record.push_back(Blob.size());
2242 
2243   // Add the strings to the blob.
2244   for (const Metadata *MD : Strings)
2245     Blob.append(cast<MDString>(MD)->getString());
2246 
2247   // Emit the final record.
2248   Stream.EmitRecordWithBlob(createMetadataStringsAbbrev(), Record, Blob);
2249   Record.clear();
2250 }
2251 
2252 // Generates an enum to use as an index in the Abbrev array of Metadata record.
2253 enum MetadataAbbrev : unsigned {
2254 #define HANDLE_MDNODE_LEAF(CLASS) CLASS##AbbrevID,
2255 #include "llvm/IR/Metadata.def"
2256   LastPlusOne
2257 };
2258 
2259 void ModuleBitcodeWriter::writeMetadataRecords(
2260     ArrayRef<const Metadata *> MDs, SmallVectorImpl<uint64_t> &Record,
2261     std::vector<unsigned> *MDAbbrevs, std::vector<uint64_t> *IndexPos) {
2262   if (MDs.empty())
2263     return;
2264 
2265   // Initialize MDNode abbreviations.
2266 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
2267 #include "llvm/IR/Metadata.def"
2268 
2269   for (const Metadata *MD : MDs) {
2270     if (IndexPos)
2271       IndexPos->push_back(Stream.GetCurrentBitNo());
2272     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
2273       assert(N->isResolved() && "Expected forward references to be resolved");
2274 
2275       switch (N->getMetadataID()) {
2276       default:
2277         llvm_unreachable("Invalid MDNode subclass");
2278 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
2279   case Metadata::CLASS##Kind:                                                  \
2280     if (MDAbbrevs)                                                             \
2281       write##CLASS(cast<CLASS>(N), Record,                                     \
2282                    (*MDAbbrevs)[MetadataAbbrev::CLASS##AbbrevID]);             \
2283     else                                                                       \
2284       write##CLASS(cast<CLASS>(N), Record, CLASS##Abbrev);                     \
2285     continue;
2286 #include "llvm/IR/Metadata.def"
2287       }
2288     }
2289     if (auto *AL = dyn_cast<DIArgList>(MD)) {
2290       writeDIArgList(AL, Record);
2291       continue;
2292     }
2293     writeValueAsMetadata(cast<ValueAsMetadata>(MD), Record);
2294   }
2295 }
2296 
2297 void ModuleBitcodeWriter::writeModuleMetadata() {
2298   if (!VE.hasMDs() && M.named_metadata_empty())
2299     return;
2300 
2301   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 4);
2302   SmallVector<uint64_t, 64> Record;
2303 
2304   // Emit all abbrevs upfront, so that the reader can jump in the middle of the
2305   // block and load any metadata.
2306   std::vector<unsigned> MDAbbrevs;
2307 
2308   MDAbbrevs.resize(MetadataAbbrev::LastPlusOne);
2309   MDAbbrevs[MetadataAbbrev::DILocationAbbrevID] = createDILocationAbbrev();
2310   MDAbbrevs[MetadataAbbrev::GenericDINodeAbbrevID] =
2311       createGenericDINodeAbbrev();
2312 
2313   auto Abbv = std::make_shared<BitCodeAbbrev>();
2314   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX_OFFSET));
2315   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2316   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2317   unsigned OffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2318 
2319   Abbv = std::make_shared<BitCodeAbbrev>();
2320   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX));
2321   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2322   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2323   unsigned IndexAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2324 
2325   // Emit MDStrings together upfront.
2326   writeMetadataStrings(VE.getMDStrings(), Record);
2327 
2328   // We only emit an index for the metadata record if we have more than a given
2329   // (naive) threshold of metadatas, otherwise it is not worth it.
2330   if (VE.getNonMDStrings().size() > IndexThreshold) {
2331     // Write a placeholder value in for the offset of the metadata index,
2332     // which is written after the records, so that it can include
2333     // the offset of each entry. The placeholder offset will be
2334     // updated after all records are emitted.
2335     uint64_t Vals[] = {0, 0};
2336     Stream.EmitRecord(bitc::METADATA_INDEX_OFFSET, Vals, OffsetAbbrev);
2337   }
2338 
2339   // Compute and save the bit offset to the current position, which will be
2340   // patched when we emit the index later. We can simply subtract the 64-bit
2341   // fixed size from the current bit number to get the location to backpatch.
2342   uint64_t IndexOffsetRecordBitPos = Stream.GetCurrentBitNo();
2343 
2344   // This index will contain the bitpos for each individual record.
2345   std::vector<uint64_t> IndexPos;
2346   IndexPos.reserve(VE.getNonMDStrings().size());
2347 
2348   // Write all the records
2349   writeMetadataRecords(VE.getNonMDStrings(), Record, &MDAbbrevs, &IndexPos);
2350 
2351   if (VE.getNonMDStrings().size() > IndexThreshold) {
2352     // Now that we have emitted all the records we will emit the index. But
2353     // first
2354     // backpatch the forward reference so that the reader can skip the records
2355     // efficiently.
2356     Stream.BackpatchWord64(IndexOffsetRecordBitPos - 64,
2357                            Stream.GetCurrentBitNo() - IndexOffsetRecordBitPos);
2358 
2359     // Delta encode the index.
2360     uint64_t PreviousValue = IndexOffsetRecordBitPos;
2361     for (auto &Elt : IndexPos) {
2362       auto EltDelta = Elt - PreviousValue;
2363       PreviousValue = Elt;
2364       Elt = EltDelta;
2365     }
2366     // Emit the index record.
2367     Stream.EmitRecord(bitc::METADATA_INDEX, IndexPos, IndexAbbrev);
2368     IndexPos.clear();
2369   }
2370 
2371   // Write the named metadata now.
2372   writeNamedMetadata(Record);
2373 
2374   auto AddDeclAttachedMetadata = [&](const GlobalObject &GO) {
2375     SmallVector<uint64_t, 4> Record;
2376     Record.push_back(VE.getValueID(&GO));
2377     pushGlobalMetadataAttachment(Record, GO);
2378     Stream.EmitRecord(bitc::METADATA_GLOBAL_DECL_ATTACHMENT, Record);
2379   };
2380   for (const Function &F : M)
2381     if (F.isDeclaration() && F.hasMetadata())
2382       AddDeclAttachedMetadata(F);
2383   // FIXME: Only store metadata for declarations here, and move data for global
2384   // variable definitions to a separate block (PR28134).
2385   for (const GlobalVariable &GV : M.globals())
2386     if (GV.hasMetadata())
2387       AddDeclAttachedMetadata(GV);
2388 
2389   Stream.ExitBlock();
2390 }
2391 
2392 void ModuleBitcodeWriter::writeFunctionMetadata(const Function &F) {
2393   if (!VE.hasMDs())
2394     return;
2395 
2396   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
2397   SmallVector<uint64_t, 64> Record;
2398   writeMetadataStrings(VE.getMDStrings(), Record);
2399   writeMetadataRecords(VE.getNonMDStrings(), Record);
2400   Stream.ExitBlock();
2401 }
2402 
2403 void ModuleBitcodeWriter::pushGlobalMetadataAttachment(
2404     SmallVectorImpl<uint64_t> &Record, const GlobalObject &GO) {
2405   // [n x [id, mdnode]]
2406   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2407   GO.getAllMetadata(MDs);
2408   for (const auto &I : MDs) {
2409     Record.push_back(I.first);
2410     Record.push_back(VE.getMetadataID(I.second));
2411   }
2412 }
2413 
2414 void ModuleBitcodeWriter::writeFunctionMetadataAttachment(const Function &F) {
2415   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
2416 
2417   SmallVector<uint64_t, 64> Record;
2418 
2419   if (F.hasMetadata()) {
2420     pushGlobalMetadataAttachment(Record, F);
2421     Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2422     Record.clear();
2423   }
2424 
2425   // Write metadata attachments
2426   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
2427   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2428   for (const BasicBlock &BB : F)
2429     for (const Instruction &I : BB) {
2430       MDs.clear();
2431       I.getAllMetadataOtherThanDebugLoc(MDs);
2432 
2433       // If no metadata, ignore instruction.
2434       if (MDs.empty()) continue;
2435 
2436       Record.push_back(VE.getInstructionID(&I));
2437 
2438       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
2439         Record.push_back(MDs[i].first);
2440         Record.push_back(VE.getMetadataID(MDs[i].second));
2441       }
2442       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2443       Record.clear();
2444     }
2445 
2446   Stream.ExitBlock();
2447 }
2448 
2449 void ModuleBitcodeWriter::writeModuleMetadataKinds() {
2450   SmallVector<uint64_t, 64> Record;
2451 
2452   // Write metadata kinds
2453   // METADATA_KIND - [n x [id, name]]
2454   SmallVector<StringRef, 8> Names;
2455   M.getMDKindNames(Names);
2456 
2457   if (Names.empty()) return;
2458 
2459   Stream.EnterSubblock(bitc::METADATA_KIND_BLOCK_ID, 3);
2460 
2461   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
2462     Record.push_back(MDKindID);
2463     StringRef KName = Names[MDKindID];
2464     Record.append(KName.begin(), KName.end());
2465 
2466     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
2467     Record.clear();
2468   }
2469 
2470   Stream.ExitBlock();
2471 }
2472 
2473 void ModuleBitcodeWriter::writeOperandBundleTags() {
2474   // Write metadata kinds
2475   //
2476   // OPERAND_BUNDLE_TAGS_BLOCK_ID : N x OPERAND_BUNDLE_TAG
2477   //
2478   // OPERAND_BUNDLE_TAG - [strchr x N]
2479 
2480   SmallVector<StringRef, 8> Tags;
2481   M.getOperandBundleTags(Tags);
2482 
2483   if (Tags.empty())
2484     return;
2485 
2486   Stream.EnterSubblock(bitc::OPERAND_BUNDLE_TAGS_BLOCK_ID, 3);
2487 
2488   SmallVector<uint64_t, 64> Record;
2489 
2490   for (auto Tag : Tags) {
2491     Record.append(Tag.begin(), Tag.end());
2492 
2493     Stream.EmitRecord(bitc::OPERAND_BUNDLE_TAG, Record, 0);
2494     Record.clear();
2495   }
2496 
2497   Stream.ExitBlock();
2498 }
2499 
2500 void ModuleBitcodeWriter::writeSyncScopeNames() {
2501   SmallVector<StringRef, 8> SSNs;
2502   M.getContext().getSyncScopeNames(SSNs);
2503   if (SSNs.empty())
2504     return;
2505 
2506   Stream.EnterSubblock(bitc::SYNC_SCOPE_NAMES_BLOCK_ID, 2);
2507 
2508   SmallVector<uint64_t, 64> Record;
2509   for (auto SSN : SSNs) {
2510     Record.append(SSN.begin(), SSN.end());
2511     Stream.EmitRecord(bitc::SYNC_SCOPE_NAME, Record, 0);
2512     Record.clear();
2513   }
2514 
2515   Stream.ExitBlock();
2516 }
2517 
2518 void ModuleBitcodeWriter::writeConstants(unsigned FirstVal, unsigned LastVal,
2519                                          bool isGlobal) {
2520   if (FirstVal == LastVal) return;
2521 
2522   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
2523 
2524   unsigned AggregateAbbrev = 0;
2525   unsigned String8Abbrev = 0;
2526   unsigned CString7Abbrev = 0;
2527   unsigned CString6Abbrev = 0;
2528   // If this is a constant pool for the module, emit module-specific abbrevs.
2529   if (isGlobal) {
2530     // Abbrev for CST_CODE_AGGREGATE.
2531     auto Abbv = std::make_shared<BitCodeAbbrev>();
2532     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
2533     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2534     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
2535     AggregateAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2536 
2537     // Abbrev for CST_CODE_STRING.
2538     Abbv = std::make_shared<BitCodeAbbrev>();
2539     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
2540     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2541     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2542     String8Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2543     // Abbrev for CST_CODE_CSTRING.
2544     Abbv = std::make_shared<BitCodeAbbrev>();
2545     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2546     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2547     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2548     CString7Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2549     // Abbrev for CST_CODE_CSTRING.
2550     Abbv = std::make_shared<BitCodeAbbrev>();
2551     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2552     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2553     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2554     CString6Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2555   }
2556 
2557   SmallVector<uint64_t, 64> Record;
2558 
2559   const ValueEnumerator::ValueList &Vals = VE.getValues();
2560   Type *LastTy = nullptr;
2561   for (unsigned i = FirstVal; i != LastVal; ++i) {
2562     const Value *V = Vals[i].first;
2563     // If we need to switch types, do so now.
2564     if (V->getType() != LastTy) {
2565       LastTy = V->getType();
2566       Record.push_back(VE.getTypeID(LastTy));
2567       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
2568                         CONSTANTS_SETTYPE_ABBREV);
2569       Record.clear();
2570     }
2571 
2572     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
2573       Record.push_back(VE.getTypeID(IA->getFunctionType()));
2574       Record.push_back(
2575           unsigned(IA->hasSideEffects()) | unsigned(IA->isAlignStack()) << 1 |
2576           unsigned(IA->getDialect() & 1) << 2 | unsigned(IA->canThrow()) << 3);
2577 
2578       // Add the asm string.
2579       const std::string &AsmStr = IA->getAsmString();
2580       Record.push_back(AsmStr.size());
2581       Record.append(AsmStr.begin(), AsmStr.end());
2582 
2583       // Add the constraint string.
2584       const std::string &ConstraintStr = IA->getConstraintString();
2585       Record.push_back(ConstraintStr.size());
2586       Record.append(ConstraintStr.begin(), ConstraintStr.end());
2587       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
2588       Record.clear();
2589       continue;
2590     }
2591     const Constant *C = cast<Constant>(V);
2592     unsigned Code = -1U;
2593     unsigned AbbrevToUse = 0;
2594     if (C->isNullValue()) {
2595       Code = bitc::CST_CODE_NULL;
2596     } else if (isa<PoisonValue>(C)) {
2597       Code = bitc::CST_CODE_POISON;
2598     } else if (isa<UndefValue>(C)) {
2599       Code = bitc::CST_CODE_UNDEF;
2600     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
2601       if (IV->getBitWidth() <= 64) {
2602         uint64_t V = IV->getSExtValue();
2603         emitSignedInt64(Record, V);
2604         Code = bitc::CST_CODE_INTEGER;
2605         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
2606       } else {                             // Wide integers, > 64 bits in size.
2607         emitWideAPInt(Record, IV->getValue());
2608         Code = bitc::CST_CODE_WIDE_INTEGER;
2609       }
2610     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
2611       Code = bitc::CST_CODE_FLOAT;
2612       Type *Ty = CFP->getType();
2613       if (Ty->isHalfTy() || Ty->isBFloatTy() || Ty->isFloatTy() ||
2614           Ty->isDoubleTy()) {
2615         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
2616       } else if (Ty->isX86_FP80Ty()) {
2617         // api needed to prevent premature destruction
2618         // bits are not in the same order as a normal i80 APInt, compensate.
2619         APInt api = CFP->getValueAPF().bitcastToAPInt();
2620         const uint64_t *p = api.getRawData();
2621         Record.push_back((p[1] << 48) | (p[0] >> 16));
2622         Record.push_back(p[0] & 0xffffLL);
2623       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
2624         APInt api = CFP->getValueAPF().bitcastToAPInt();
2625         const uint64_t *p = api.getRawData();
2626         Record.push_back(p[0]);
2627         Record.push_back(p[1]);
2628       } else {
2629         assert(0 && "Unknown FP type!");
2630       }
2631     } else if (isa<ConstantDataSequential>(C) &&
2632                cast<ConstantDataSequential>(C)->isString()) {
2633       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
2634       // Emit constant strings specially.
2635       unsigned NumElts = Str->getNumElements();
2636       // If this is a null-terminated string, use the denser CSTRING encoding.
2637       if (Str->isCString()) {
2638         Code = bitc::CST_CODE_CSTRING;
2639         --NumElts;  // Don't encode the null, which isn't allowed by char6.
2640       } else {
2641         Code = bitc::CST_CODE_STRING;
2642         AbbrevToUse = String8Abbrev;
2643       }
2644       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
2645       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
2646       for (unsigned i = 0; i != NumElts; ++i) {
2647         unsigned char V = Str->getElementAsInteger(i);
2648         Record.push_back(V);
2649         isCStr7 &= (V & 128) == 0;
2650         if (isCStrChar6)
2651           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
2652       }
2653 
2654       if (isCStrChar6)
2655         AbbrevToUse = CString6Abbrev;
2656       else if (isCStr7)
2657         AbbrevToUse = CString7Abbrev;
2658     } else if (const ConstantDataSequential *CDS =
2659                   dyn_cast<ConstantDataSequential>(C)) {
2660       Code = bitc::CST_CODE_DATA;
2661       Type *EltTy = CDS->getElementType();
2662       if (isa<IntegerType>(EltTy)) {
2663         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2664           Record.push_back(CDS->getElementAsInteger(i));
2665       } else {
2666         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2667           Record.push_back(
2668               CDS->getElementAsAPFloat(i).bitcastToAPInt().getLimitedValue());
2669       }
2670     } else if (isa<ConstantAggregate>(C)) {
2671       Code = bitc::CST_CODE_AGGREGATE;
2672       for (const Value *Op : C->operands())
2673         Record.push_back(VE.getValueID(Op));
2674       AbbrevToUse = AggregateAbbrev;
2675     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
2676       switch (CE->getOpcode()) {
2677       default:
2678         if (Instruction::isCast(CE->getOpcode())) {
2679           Code = bitc::CST_CODE_CE_CAST;
2680           Record.push_back(getEncodedCastOpcode(CE->getOpcode()));
2681           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2682           Record.push_back(VE.getValueID(C->getOperand(0)));
2683           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
2684         } else {
2685           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
2686           Code = bitc::CST_CODE_CE_BINOP;
2687           Record.push_back(getEncodedBinaryOpcode(CE->getOpcode()));
2688           Record.push_back(VE.getValueID(C->getOperand(0)));
2689           Record.push_back(VE.getValueID(C->getOperand(1)));
2690           uint64_t Flags = getOptimizationFlags(CE);
2691           if (Flags != 0)
2692             Record.push_back(Flags);
2693         }
2694         break;
2695       case Instruction::FNeg: {
2696         assert(CE->getNumOperands() == 1 && "Unknown constant expr!");
2697         Code = bitc::CST_CODE_CE_UNOP;
2698         Record.push_back(getEncodedUnaryOpcode(CE->getOpcode()));
2699         Record.push_back(VE.getValueID(C->getOperand(0)));
2700         uint64_t Flags = getOptimizationFlags(CE);
2701         if (Flags != 0)
2702           Record.push_back(Flags);
2703         break;
2704       }
2705       case Instruction::GetElementPtr: {
2706         Code = bitc::CST_CODE_CE_GEP;
2707         const auto *GO = cast<GEPOperator>(C);
2708         Record.push_back(VE.getTypeID(GO->getSourceElementType()));
2709         if (std::optional<unsigned> Idx = GO->getInRangeIndex()) {
2710           Code = bitc::CST_CODE_CE_GEP_WITH_INRANGE_INDEX;
2711           Record.push_back((*Idx << 1) | GO->isInBounds());
2712         } else if (GO->isInBounds())
2713           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
2714         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
2715           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
2716           Record.push_back(VE.getValueID(C->getOperand(i)));
2717         }
2718         break;
2719       }
2720       case Instruction::ExtractElement:
2721         Code = bitc::CST_CODE_CE_EXTRACTELT;
2722         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2723         Record.push_back(VE.getValueID(C->getOperand(0)));
2724         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
2725         Record.push_back(VE.getValueID(C->getOperand(1)));
2726         break;
2727       case Instruction::InsertElement:
2728         Code = bitc::CST_CODE_CE_INSERTELT;
2729         Record.push_back(VE.getValueID(C->getOperand(0)));
2730         Record.push_back(VE.getValueID(C->getOperand(1)));
2731         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
2732         Record.push_back(VE.getValueID(C->getOperand(2)));
2733         break;
2734       case Instruction::ShuffleVector:
2735         // If the return type and argument types are the same, this is a
2736         // standard shufflevector instruction.  If the types are different,
2737         // then the shuffle is widening or truncating the input vectors, and
2738         // the argument type must also be encoded.
2739         if (C->getType() == C->getOperand(0)->getType()) {
2740           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
2741         } else {
2742           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
2743           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2744         }
2745         Record.push_back(VE.getValueID(C->getOperand(0)));
2746         Record.push_back(VE.getValueID(C->getOperand(1)));
2747         Record.push_back(VE.getValueID(CE->getShuffleMaskForBitcode()));
2748         break;
2749       case Instruction::ICmp:
2750       case Instruction::FCmp:
2751         Code = bitc::CST_CODE_CE_CMP;
2752         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2753         Record.push_back(VE.getValueID(C->getOperand(0)));
2754         Record.push_back(VE.getValueID(C->getOperand(1)));
2755         Record.push_back(CE->getPredicate());
2756         break;
2757       }
2758     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
2759       Code = bitc::CST_CODE_BLOCKADDRESS;
2760       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
2761       Record.push_back(VE.getValueID(BA->getFunction()));
2762       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
2763     } else if (const auto *Equiv = dyn_cast<DSOLocalEquivalent>(C)) {
2764       Code = bitc::CST_CODE_DSO_LOCAL_EQUIVALENT;
2765       Record.push_back(VE.getTypeID(Equiv->getGlobalValue()->getType()));
2766       Record.push_back(VE.getValueID(Equiv->getGlobalValue()));
2767     } else if (const auto *NC = dyn_cast<NoCFIValue>(C)) {
2768       Code = bitc::CST_CODE_NO_CFI_VALUE;
2769       Record.push_back(VE.getTypeID(NC->getGlobalValue()->getType()));
2770       Record.push_back(VE.getValueID(NC->getGlobalValue()));
2771     } else {
2772 #ifndef NDEBUG
2773       C->dump();
2774 #endif
2775       llvm_unreachable("Unknown constant!");
2776     }
2777     Stream.EmitRecord(Code, Record, AbbrevToUse);
2778     Record.clear();
2779   }
2780 
2781   Stream.ExitBlock();
2782 }
2783 
2784 void ModuleBitcodeWriter::writeModuleConstants() {
2785   const ValueEnumerator::ValueList &Vals = VE.getValues();
2786 
2787   // Find the first constant to emit, which is the first non-globalvalue value.
2788   // We know globalvalues have been emitted by WriteModuleInfo.
2789   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
2790     if (!isa<GlobalValue>(Vals[i].first)) {
2791       writeConstants(i, Vals.size(), true);
2792       return;
2793     }
2794   }
2795 }
2796 
2797 /// pushValueAndType - The file has to encode both the value and type id for
2798 /// many values, because we need to know what type to create for forward
2799 /// references.  However, most operands are not forward references, so this type
2800 /// field is not needed.
2801 ///
2802 /// This function adds V's value ID to Vals.  If the value ID is higher than the
2803 /// instruction ID, then it is a forward reference, and it also includes the
2804 /// type ID.  The value ID that is written is encoded relative to the InstID.
2805 bool ModuleBitcodeWriter::pushValueAndType(const Value *V, unsigned InstID,
2806                                            SmallVectorImpl<unsigned> &Vals) {
2807   unsigned ValID = VE.getValueID(V);
2808   // Make encoding relative to the InstID.
2809   Vals.push_back(InstID - ValID);
2810   if (ValID >= InstID) {
2811     Vals.push_back(VE.getTypeID(V->getType()));
2812     return true;
2813   }
2814   return false;
2815 }
2816 
2817 void ModuleBitcodeWriter::writeOperandBundles(const CallBase &CS,
2818                                               unsigned InstID) {
2819   SmallVector<unsigned, 64> Record;
2820   LLVMContext &C = CS.getContext();
2821 
2822   for (unsigned i = 0, e = CS.getNumOperandBundles(); i != e; ++i) {
2823     const auto &Bundle = CS.getOperandBundleAt(i);
2824     Record.push_back(C.getOperandBundleTagID(Bundle.getTagName()));
2825 
2826     for (auto &Input : Bundle.Inputs)
2827       pushValueAndType(Input, InstID, Record);
2828 
2829     Stream.EmitRecord(bitc::FUNC_CODE_OPERAND_BUNDLE, Record);
2830     Record.clear();
2831   }
2832 }
2833 
2834 /// pushValue - Like pushValueAndType, but where the type of the value is
2835 /// omitted (perhaps it was already encoded in an earlier operand).
2836 void ModuleBitcodeWriter::pushValue(const Value *V, unsigned InstID,
2837                                     SmallVectorImpl<unsigned> &Vals) {
2838   unsigned ValID = VE.getValueID(V);
2839   Vals.push_back(InstID - ValID);
2840 }
2841 
2842 void ModuleBitcodeWriter::pushValueSigned(const Value *V, unsigned InstID,
2843                                           SmallVectorImpl<uint64_t> &Vals) {
2844   unsigned ValID = VE.getValueID(V);
2845   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
2846   emitSignedInt64(Vals, diff);
2847 }
2848 
2849 /// WriteInstruction - Emit an instruction to the specified stream.
2850 void ModuleBitcodeWriter::writeInstruction(const Instruction &I,
2851                                            unsigned InstID,
2852                                            SmallVectorImpl<unsigned> &Vals) {
2853   unsigned Code = 0;
2854   unsigned AbbrevToUse = 0;
2855   VE.setInstructionID(&I);
2856   switch (I.getOpcode()) {
2857   default:
2858     if (Instruction::isCast(I.getOpcode())) {
2859       Code = bitc::FUNC_CODE_INST_CAST;
2860       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2861         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
2862       Vals.push_back(VE.getTypeID(I.getType()));
2863       Vals.push_back(getEncodedCastOpcode(I.getOpcode()));
2864       uint64_t Flags = getOptimizationFlags(&I);
2865       if (Flags != 0) {
2866         if (AbbrevToUse == FUNCTION_INST_CAST_ABBREV)
2867           AbbrevToUse = FUNCTION_INST_CAST_FLAGS_ABBREV;
2868         Vals.push_back(Flags);
2869       }
2870     } else {
2871       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
2872       Code = bitc::FUNC_CODE_INST_BINOP;
2873       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2874         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
2875       pushValue(I.getOperand(1), InstID, Vals);
2876       Vals.push_back(getEncodedBinaryOpcode(I.getOpcode()));
2877       uint64_t Flags = getOptimizationFlags(&I);
2878       if (Flags != 0) {
2879         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
2880           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
2881         Vals.push_back(Flags);
2882       }
2883     }
2884     break;
2885   case Instruction::FNeg: {
2886     Code = bitc::FUNC_CODE_INST_UNOP;
2887     if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2888       AbbrevToUse = FUNCTION_INST_UNOP_ABBREV;
2889     Vals.push_back(getEncodedUnaryOpcode(I.getOpcode()));
2890     uint64_t Flags = getOptimizationFlags(&I);
2891     if (Flags != 0) {
2892       if (AbbrevToUse == FUNCTION_INST_UNOP_ABBREV)
2893         AbbrevToUse = FUNCTION_INST_UNOP_FLAGS_ABBREV;
2894       Vals.push_back(Flags);
2895     }
2896     break;
2897   }
2898   case Instruction::GetElementPtr: {
2899     Code = bitc::FUNC_CODE_INST_GEP;
2900     AbbrevToUse = FUNCTION_INST_GEP_ABBREV;
2901     auto &GEPInst = cast<GetElementPtrInst>(I);
2902     Vals.push_back(GEPInst.isInBounds());
2903     Vals.push_back(VE.getTypeID(GEPInst.getSourceElementType()));
2904     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
2905       pushValueAndType(I.getOperand(i), InstID, Vals);
2906     break;
2907   }
2908   case Instruction::ExtractValue: {
2909     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
2910     pushValueAndType(I.getOperand(0), InstID, Vals);
2911     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
2912     Vals.append(EVI->idx_begin(), EVI->idx_end());
2913     break;
2914   }
2915   case Instruction::InsertValue: {
2916     Code = bitc::FUNC_CODE_INST_INSERTVAL;
2917     pushValueAndType(I.getOperand(0), InstID, Vals);
2918     pushValueAndType(I.getOperand(1), InstID, Vals);
2919     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
2920     Vals.append(IVI->idx_begin(), IVI->idx_end());
2921     break;
2922   }
2923   case Instruction::Select: {
2924     Code = bitc::FUNC_CODE_INST_VSELECT;
2925     pushValueAndType(I.getOperand(1), InstID, Vals);
2926     pushValue(I.getOperand(2), InstID, Vals);
2927     pushValueAndType(I.getOperand(0), InstID, Vals);
2928     uint64_t Flags = getOptimizationFlags(&I);
2929     if (Flags != 0)
2930       Vals.push_back(Flags);
2931     break;
2932   }
2933   case Instruction::ExtractElement:
2934     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
2935     pushValueAndType(I.getOperand(0), InstID, Vals);
2936     pushValueAndType(I.getOperand(1), InstID, Vals);
2937     break;
2938   case Instruction::InsertElement:
2939     Code = bitc::FUNC_CODE_INST_INSERTELT;
2940     pushValueAndType(I.getOperand(0), InstID, Vals);
2941     pushValue(I.getOperand(1), InstID, Vals);
2942     pushValueAndType(I.getOperand(2), InstID, Vals);
2943     break;
2944   case Instruction::ShuffleVector:
2945     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
2946     pushValueAndType(I.getOperand(0), InstID, Vals);
2947     pushValue(I.getOperand(1), InstID, Vals);
2948     pushValue(cast<ShuffleVectorInst>(I).getShuffleMaskForBitcode(), InstID,
2949               Vals);
2950     break;
2951   case Instruction::ICmp:
2952   case Instruction::FCmp: {
2953     // compare returning Int1Ty or vector of Int1Ty
2954     Code = bitc::FUNC_CODE_INST_CMP2;
2955     pushValueAndType(I.getOperand(0), InstID, Vals);
2956     pushValue(I.getOperand(1), InstID, Vals);
2957     Vals.push_back(cast<CmpInst>(I).getPredicate());
2958     uint64_t Flags = getOptimizationFlags(&I);
2959     if (Flags != 0)
2960       Vals.push_back(Flags);
2961     break;
2962   }
2963 
2964   case Instruction::Ret:
2965     {
2966       Code = bitc::FUNC_CODE_INST_RET;
2967       unsigned NumOperands = I.getNumOperands();
2968       if (NumOperands == 0)
2969         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
2970       else if (NumOperands == 1) {
2971         if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2972           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
2973       } else {
2974         for (unsigned i = 0, e = NumOperands; i != e; ++i)
2975           pushValueAndType(I.getOperand(i), InstID, Vals);
2976       }
2977     }
2978     break;
2979   case Instruction::Br:
2980     {
2981       Code = bitc::FUNC_CODE_INST_BR;
2982       const BranchInst &II = cast<BranchInst>(I);
2983       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
2984       if (II.isConditional()) {
2985         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
2986         pushValue(II.getCondition(), InstID, Vals);
2987       }
2988     }
2989     break;
2990   case Instruction::Switch:
2991     {
2992       Code = bitc::FUNC_CODE_INST_SWITCH;
2993       const SwitchInst &SI = cast<SwitchInst>(I);
2994       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
2995       pushValue(SI.getCondition(), InstID, Vals);
2996       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
2997       for (auto Case : SI.cases()) {
2998         Vals.push_back(VE.getValueID(Case.getCaseValue()));
2999         Vals.push_back(VE.getValueID(Case.getCaseSuccessor()));
3000       }
3001     }
3002     break;
3003   case Instruction::IndirectBr:
3004     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
3005     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
3006     // Encode the address operand as relative, but not the basic blocks.
3007     pushValue(I.getOperand(0), InstID, Vals);
3008     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
3009       Vals.push_back(VE.getValueID(I.getOperand(i)));
3010     break;
3011 
3012   case Instruction::Invoke: {
3013     const InvokeInst *II = cast<InvokeInst>(&I);
3014     const Value *Callee = II->getCalledOperand();
3015     FunctionType *FTy = II->getFunctionType();
3016 
3017     if (II->hasOperandBundles())
3018       writeOperandBundles(*II, InstID);
3019 
3020     Code = bitc::FUNC_CODE_INST_INVOKE;
3021 
3022     Vals.push_back(VE.getAttributeListID(II->getAttributes()));
3023     Vals.push_back(II->getCallingConv() | 1 << 13);
3024     Vals.push_back(VE.getValueID(II->getNormalDest()));
3025     Vals.push_back(VE.getValueID(II->getUnwindDest()));
3026     Vals.push_back(VE.getTypeID(FTy));
3027     pushValueAndType(Callee, InstID, Vals);
3028 
3029     // Emit value #'s for the fixed parameters.
3030     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
3031       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
3032 
3033     // Emit type/value pairs for varargs params.
3034     if (FTy->isVarArg()) {
3035       for (unsigned i = FTy->getNumParams(), e = II->arg_size(); i != e; ++i)
3036         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
3037     }
3038     break;
3039   }
3040   case Instruction::Resume:
3041     Code = bitc::FUNC_CODE_INST_RESUME;
3042     pushValueAndType(I.getOperand(0), InstID, Vals);
3043     break;
3044   case Instruction::CleanupRet: {
3045     Code = bitc::FUNC_CODE_INST_CLEANUPRET;
3046     const auto &CRI = cast<CleanupReturnInst>(I);
3047     pushValue(CRI.getCleanupPad(), InstID, Vals);
3048     if (CRI.hasUnwindDest())
3049       Vals.push_back(VE.getValueID(CRI.getUnwindDest()));
3050     break;
3051   }
3052   case Instruction::CatchRet: {
3053     Code = bitc::FUNC_CODE_INST_CATCHRET;
3054     const auto &CRI = cast<CatchReturnInst>(I);
3055     pushValue(CRI.getCatchPad(), InstID, Vals);
3056     Vals.push_back(VE.getValueID(CRI.getSuccessor()));
3057     break;
3058   }
3059   case Instruction::CleanupPad:
3060   case Instruction::CatchPad: {
3061     const auto &FuncletPad = cast<FuncletPadInst>(I);
3062     Code = isa<CatchPadInst>(FuncletPad) ? bitc::FUNC_CODE_INST_CATCHPAD
3063                                          : bitc::FUNC_CODE_INST_CLEANUPPAD;
3064     pushValue(FuncletPad.getParentPad(), InstID, Vals);
3065 
3066     unsigned NumArgOperands = FuncletPad.arg_size();
3067     Vals.push_back(NumArgOperands);
3068     for (unsigned Op = 0; Op != NumArgOperands; ++Op)
3069       pushValueAndType(FuncletPad.getArgOperand(Op), InstID, Vals);
3070     break;
3071   }
3072   case Instruction::CatchSwitch: {
3073     Code = bitc::FUNC_CODE_INST_CATCHSWITCH;
3074     const auto &CatchSwitch = cast<CatchSwitchInst>(I);
3075 
3076     pushValue(CatchSwitch.getParentPad(), InstID, Vals);
3077 
3078     unsigned NumHandlers = CatchSwitch.getNumHandlers();
3079     Vals.push_back(NumHandlers);
3080     for (const BasicBlock *CatchPadBB : CatchSwitch.handlers())
3081       Vals.push_back(VE.getValueID(CatchPadBB));
3082 
3083     if (CatchSwitch.hasUnwindDest())
3084       Vals.push_back(VE.getValueID(CatchSwitch.getUnwindDest()));
3085     break;
3086   }
3087   case Instruction::CallBr: {
3088     const CallBrInst *CBI = cast<CallBrInst>(&I);
3089     const Value *Callee = CBI->getCalledOperand();
3090     FunctionType *FTy = CBI->getFunctionType();
3091 
3092     if (CBI->hasOperandBundles())
3093       writeOperandBundles(*CBI, InstID);
3094 
3095     Code = bitc::FUNC_CODE_INST_CALLBR;
3096 
3097     Vals.push_back(VE.getAttributeListID(CBI->getAttributes()));
3098 
3099     Vals.push_back(CBI->getCallingConv() << bitc::CALL_CCONV |
3100                    1 << bitc::CALL_EXPLICIT_TYPE);
3101 
3102     Vals.push_back(VE.getValueID(CBI->getDefaultDest()));
3103     Vals.push_back(CBI->getNumIndirectDests());
3104     for (unsigned i = 0, e = CBI->getNumIndirectDests(); i != e; ++i)
3105       Vals.push_back(VE.getValueID(CBI->getIndirectDest(i)));
3106 
3107     Vals.push_back(VE.getTypeID(FTy));
3108     pushValueAndType(Callee, InstID, Vals);
3109 
3110     // Emit value #'s for the fixed parameters.
3111     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
3112       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
3113 
3114     // Emit type/value pairs for varargs params.
3115     if (FTy->isVarArg()) {
3116       for (unsigned i = FTy->getNumParams(), e = CBI->arg_size(); i != e; ++i)
3117         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
3118     }
3119     break;
3120   }
3121   case Instruction::Unreachable:
3122     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
3123     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
3124     break;
3125 
3126   case Instruction::PHI: {
3127     const PHINode &PN = cast<PHINode>(I);
3128     Code = bitc::FUNC_CODE_INST_PHI;
3129     // With the newer instruction encoding, forward references could give
3130     // negative valued IDs.  This is most common for PHIs, so we use
3131     // signed VBRs.
3132     SmallVector<uint64_t, 128> Vals64;
3133     Vals64.push_back(VE.getTypeID(PN.getType()));
3134     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
3135       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64);
3136       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
3137     }
3138 
3139     uint64_t Flags = getOptimizationFlags(&I);
3140     if (Flags != 0)
3141       Vals64.push_back(Flags);
3142 
3143     // Emit a Vals64 vector and exit.
3144     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
3145     Vals64.clear();
3146     return;
3147   }
3148 
3149   case Instruction::LandingPad: {
3150     const LandingPadInst &LP = cast<LandingPadInst>(I);
3151     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
3152     Vals.push_back(VE.getTypeID(LP.getType()));
3153     Vals.push_back(LP.isCleanup());
3154     Vals.push_back(LP.getNumClauses());
3155     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
3156       if (LP.isCatch(I))
3157         Vals.push_back(LandingPadInst::Catch);
3158       else
3159         Vals.push_back(LandingPadInst::Filter);
3160       pushValueAndType(LP.getClause(I), InstID, Vals);
3161     }
3162     break;
3163   }
3164 
3165   case Instruction::Alloca: {
3166     Code = bitc::FUNC_CODE_INST_ALLOCA;
3167     const AllocaInst &AI = cast<AllocaInst>(I);
3168     Vals.push_back(VE.getTypeID(AI.getAllocatedType()));
3169     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
3170     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
3171     using APV = AllocaPackedValues;
3172     unsigned Record = 0;
3173     unsigned EncodedAlign = getEncodedAlign(AI.getAlign());
3174     Bitfield::set<APV::AlignLower>(
3175         Record, EncodedAlign & ((1 << APV::AlignLower::Bits) - 1));
3176     Bitfield::set<APV::AlignUpper>(Record,
3177                                    EncodedAlign >> APV::AlignLower::Bits);
3178     Bitfield::set<APV::UsedWithInAlloca>(Record, AI.isUsedWithInAlloca());
3179     Bitfield::set<APV::ExplicitType>(Record, true);
3180     Bitfield::set<APV::SwiftError>(Record, AI.isSwiftError());
3181     Vals.push_back(Record);
3182 
3183     unsigned AS = AI.getAddressSpace();
3184     if (AS != M.getDataLayout().getAllocaAddrSpace())
3185       Vals.push_back(AS);
3186     break;
3187   }
3188 
3189   case Instruction::Load:
3190     if (cast<LoadInst>(I).isAtomic()) {
3191       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
3192       pushValueAndType(I.getOperand(0), InstID, Vals);
3193     } else {
3194       Code = bitc::FUNC_CODE_INST_LOAD;
3195       if (!pushValueAndType(I.getOperand(0), InstID, Vals)) // ptr
3196         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
3197     }
3198     Vals.push_back(VE.getTypeID(I.getType()));
3199     Vals.push_back(getEncodedAlign(cast<LoadInst>(I).getAlign()));
3200     Vals.push_back(cast<LoadInst>(I).isVolatile());
3201     if (cast<LoadInst>(I).isAtomic()) {
3202       Vals.push_back(getEncodedOrdering(cast<LoadInst>(I).getOrdering()));
3203       Vals.push_back(getEncodedSyncScopeID(cast<LoadInst>(I).getSyncScopeID()));
3204     }
3205     break;
3206   case Instruction::Store:
3207     if (cast<StoreInst>(I).isAtomic())
3208       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
3209     else
3210       Code = bitc::FUNC_CODE_INST_STORE;
3211     pushValueAndType(I.getOperand(1), InstID, Vals); // ptrty + ptr
3212     pushValueAndType(I.getOperand(0), InstID, Vals); // valty + val
3213     Vals.push_back(getEncodedAlign(cast<StoreInst>(I).getAlign()));
3214     Vals.push_back(cast<StoreInst>(I).isVolatile());
3215     if (cast<StoreInst>(I).isAtomic()) {
3216       Vals.push_back(getEncodedOrdering(cast<StoreInst>(I).getOrdering()));
3217       Vals.push_back(
3218           getEncodedSyncScopeID(cast<StoreInst>(I).getSyncScopeID()));
3219     }
3220     break;
3221   case Instruction::AtomicCmpXchg:
3222     Code = bitc::FUNC_CODE_INST_CMPXCHG;
3223     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
3224     pushValueAndType(I.getOperand(1), InstID, Vals); // cmp.
3225     pushValue(I.getOperand(2), InstID, Vals);        // newval.
3226     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
3227     Vals.push_back(
3228         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
3229     Vals.push_back(
3230         getEncodedSyncScopeID(cast<AtomicCmpXchgInst>(I).getSyncScopeID()));
3231     Vals.push_back(
3232         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
3233     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
3234     Vals.push_back(getEncodedAlign(cast<AtomicCmpXchgInst>(I).getAlign()));
3235     break;
3236   case Instruction::AtomicRMW:
3237     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
3238     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
3239     pushValueAndType(I.getOperand(1), InstID, Vals); // valty + val
3240     Vals.push_back(
3241         getEncodedRMWOperation(cast<AtomicRMWInst>(I).getOperation()));
3242     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
3243     Vals.push_back(getEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
3244     Vals.push_back(
3245         getEncodedSyncScopeID(cast<AtomicRMWInst>(I).getSyncScopeID()));
3246     Vals.push_back(getEncodedAlign(cast<AtomicRMWInst>(I).getAlign()));
3247     break;
3248   case Instruction::Fence:
3249     Code = bitc::FUNC_CODE_INST_FENCE;
3250     Vals.push_back(getEncodedOrdering(cast<FenceInst>(I).getOrdering()));
3251     Vals.push_back(getEncodedSyncScopeID(cast<FenceInst>(I).getSyncScopeID()));
3252     break;
3253   case Instruction::Call: {
3254     const CallInst &CI = cast<CallInst>(I);
3255     FunctionType *FTy = CI.getFunctionType();
3256 
3257     if (CI.hasOperandBundles())
3258       writeOperandBundles(CI, InstID);
3259 
3260     Code = bitc::FUNC_CODE_INST_CALL;
3261 
3262     Vals.push_back(VE.getAttributeListID(CI.getAttributes()));
3263 
3264     unsigned Flags = getOptimizationFlags(&I);
3265     Vals.push_back(CI.getCallingConv() << bitc::CALL_CCONV |
3266                    unsigned(CI.isTailCall()) << bitc::CALL_TAIL |
3267                    unsigned(CI.isMustTailCall()) << bitc::CALL_MUSTTAIL |
3268                    1 << bitc::CALL_EXPLICIT_TYPE |
3269                    unsigned(CI.isNoTailCall()) << bitc::CALL_NOTAIL |
3270                    unsigned(Flags != 0) << bitc::CALL_FMF);
3271     if (Flags != 0)
3272       Vals.push_back(Flags);
3273 
3274     Vals.push_back(VE.getTypeID(FTy));
3275     pushValueAndType(CI.getCalledOperand(), InstID, Vals); // Callee
3276 
3277     // Emit value #'s for the fixed parameters.
3278     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
3279       // Check for labels (can happen with asm labels).
3280       if (FTy->getParamType(i)->isLabelTy())
3281         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
3282       else
3283         pushValue(CI.getArgOperand(i), InstID, Vals); // fixed param.
3284     }
3285 
3286     // Emit type/value pairs for varargs params.
3287     if (FTy->isVarArg()) {
3288       for (unsigned i = FTy->getNumParams(), e = CI.arg_size(); i != e; ++i)
3289         pushValueAndType(CI.getArgOperand(i), InstID, Vals); // varargs
3290     }
3291     break;
3292   }
3293   case Instruction::VAArg:
3294     Code = bitc::FUNC_CODE_INST_VAARG;
3295     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
3296     pushValue(I.getOperand(0), InstID, Vals);                   // valist.
3297     Vals.push_back(VE.getTypeID(I.getType())); // restype.
3298     break;
3299   case Instruction::Freeze:
3300     Code = bitc::FUNC_CODE_INST_FREEZE;
3301     pushValueAndType(I.getOperand(0), InstID, Vals);
3302     break;
3303   }
3304 
3305   Stream.EmitRecord(Code, Vals, AbbrevToUse);
3306   Vals.clear();
3307 }
3308 
3309 /// Write a GlobalValue VST to the module. The purpose of this data structure is
3310 /// to allow clients to efficiently find the function body.
3311 void ModuleBitcodeWriter::writeGlobalValueSymbolTable(
3312   DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3313   // Get the offset of the VST we are writing, and backpatch it into
3314   // the VST forward declaration record.
3315   uint64_t VSTOffset = Stream.GetCurrentBitNo();
3316   // The BitcodeStartBit was the stream offset of the identification block.
3317   VSTOffset -= bitcodeStartBit();
3318   assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
3319   // Note that we add 1 here because the offset is relative to one word
3320   // before the start of the identification block, which was historically
3321   // always the start of the regular bitcode header.
3322   Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32 + 1);
3323 
3324   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3325 
3326   auto Abbv = std::make_shared<BitCodeAbbrev>();
3327   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
3328   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
3329   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
3330   unsigned FnEntryAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3331 
3332   for (const Function &F : M) {
3333     uint64_t Record[2];
3334 
3335     if (F.isDeclaration())
3336       continue;
3337 
3338     Record[0] = VE.getValueID(&F);
3339 
3340     // Save the word offset of the function (from the start of the
3341     // actual bitcode written to the stream).
3342     uint64_t BitcodeIndex = FunctionToBitcodeIndex[&F] - bitcodeStartBit();
3343     assert((BitcodeIndex & 31) == 0 && "function block not 32-bit aligned");
3344     // Note that we add 1 here because the offset is relative to one word
3345     // before the start of the identification block, which was historically
3346     // always the start of the regular bitcode header.
3347     Record[1] = BitcodeIndex / 32 + 1;
3348 
3349     Stream.EmitRecord(bitc::VST_CODE_FNENTRY, Record, FnEntryAbbrev);
3350   }
3351 
3352   Stream.ExitBlock();
3353 }
3354 
3355 /// Emit names for arguments, instructions and basic blocks in a function.
3356 void ModuleBitcodeWriter::writeFunctionLevelValueSymbolTable(
3357     const ValueSymbolTable &VST) {
3358   if (VST.empty())
3359     return;
3360 
3361   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3362 
3363   // FIXME: Set up the abbrev, we know how many values there are!
3364   // FIXME: We know if the type names can use 7-bit ascii.
3365   SmallVector<uint64_t, 64> NameVals;
3366 
3367   for (const ValueName &Name : VST) {
3368     // Figure out the encoding to use for the name.
3369     StringEncoding Bits = getStringEncoding(Name.getKey());
3370 
3371     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
3372     NameVals.push_back(VE.getValueID(Name.getValue()));
3373 
3374     // VST_CODE_ENTRY:   [valueid, namechar x N]
3375     // VST_CODE_BBENTRY: [bbid, namechar x N]
3376     unsigned Code;
3377     if (isa<BasicBlock>(Name.getValue())) {
3378       Code = bitc::VST_CODE_BBENTRY;
3379       if (Bits == SE_Char6)
3380         AbbrevToUse = VST_BBENTRY_6_ABBREV;
3381     } else {
3382       Code = bitc::VST_CODE_ENTRY;
3383       if (Bits == SE_Char6)
3384         AbbrevToUse = VST_ENTRY_6_ABBREV;
3385       else if (Bits == SE_Fixed7)
3386         AbbrevToUse = VST_ENTRY_7_ABBREV;
3387     }
3388 
3389     for (const auto P : Name.getKey())
3390       NameVals.push_back((unsigned char)P);
3391 
3392     // Emit the finished record.
3393     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
3394     NameVals.clear();
3395   }
3396 
3397   Stream.ExitBlock();
3398 }
3399 
3400 void ModuleBitcodeWriter::writeUseList(UseListOrder &&Order) {
3401   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
3402   unsigned Code;
3403   if (isa<BasicBlock>(Order.V))
3404     Code = bitc::USELIST_CODE_BB;
3405   else
3406     Code = bitc::USELIST_CODE_DEFAULT;
3407 
3408   SmallVector<uint64_t, 64> Record(Order.Shuffle.begin(), Order.Shuffle.end());
3409   Record.push_back(VE.getValueID(Order.V));
3410   Stream.EmitRecord(Code, Record);
3411 }
3412 
3413 void ModuleBitcodeWriter::writeUseListBlock(const Function *F) {
3414   assert(VE.shouldPreserveUseListOrder() &&
3415          "Expected to be preserving use-list order");
3416 
3417   auto hasMore = [&]() {
3418     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
3419   };
3420   if (!hasMore())
3421     // Nothing to do.
3422     return;
3423 
3424   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
3425   while (hasMore()) {
3426     writeUseList(std::move(VE.UseListOrders.back()));
3427     VE.UseListOrders.pop_back();
3428   }
3429   Stream.ExitBlock();
3430 }
3431 
3432 /// Emit a function body to the module stream.
3433 void ModuleBitcodeWriter::writeFunction(
3434     const Function &F,
3435     DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3436   // Save the bitcode index of the start of this function block for recording
3437   // in the VST.
3438   FunctionToBitcodeIndex[&F] = Stream.GetCurrentBitNo();
3439 
3440   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
3441   VE.incorporateFunction(F);
3442 
3443   SmallVector<unsigned, 64> Vals;
3444 
3445   // Emit the number of basic blocks, so the reader can create them ahead of
3446   // time.
3447   Vals.push_back(VE.getBasicBlocks().size());
3448   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
3449   Vals.clear();
3450 
3451   // If there are function-local constants, emit them now.
3452   unsigned CstStart, CstEnd;
3453   VE.getFunctionConstantRange(CstStart, CstEnd);
3454   writeConstants(CstStart, CstEnd, false);
3455 
3456   // If there is function-local metadata, emit it now.
3457   writeFunctionMetadata(F);
3458 
3459   // Keep a running idea of what the instruction ID is.
3460   unsigned InstID = CstEnd;
3461 
3462   bool NeedsMetadataAttachment = F.hasMetadata();
3463 
3464   DILocation *LastDL = nullptr;
3465   SmallSetVector<Function *, 4> BlockAddressUsers;
3466 
3467   // Finally, emit all the instructions, in order.
3468   for (const BasicBlock &BB : F) {
3469     for (const Instruction &I : BB) {
3470       writeInstruction(I, InstID, Vals);
3471 
3472       if (!I.getType()->isVoidTy())
3473         ++InstID;
3474 
3475       // If the instruction has metadata, write a metadata attachment later.
3476       NeedsMetadataAttachment |= I.hasMetadataOtherThanDebugLoc();
3477 
3478       // If the instruction has a debug location, emit it.
3479       DILocation *DL = I.getDebugLoc();
3480       if (!DL)
3481         continue;
3482 
3483       if (DL == LastDL) {
3484         // Just repeat the same debug loc as last time.
3485         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
3486         continue;
3487       }
3488 
3489       Vals.push_back(DL->getLine());
3490       Vals.push_back(DL->getColumn());
3491       Vals.push_back(VE.getMetadataOrNullID(DL->getScope()));
3492       Vals.push_back(VE.getMetadataOrNullID(DL->getInlinedAt()));
3493       Vals.push_back(DL->isImplicitCode());
3494       Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
3495       Vals.clear();
3496 
3497       LastDL = DL;
3498     }
3499 
3500     if (BlockAddress *BA = BlockAddress::lookup(&BB)) {
3501       SmallVector<Value *> Worklist{BA};
3502       SmallPtrSet<Value *, 8> Visited{BA};
3503       while (!Worklist.empty()) {
3504         Value *V = Worklist.pop_back_val();
3505         for (User *U : V->users()) {
3506           if (auto *I = dyn_cast<Instruction>(U)) {
3507             Function *P = I->getFunction();
3508             if (P != &F)
3509               BlockAddressUsers.insert(P);
3510           } else if (isa<Constant>(U) && !isa<GlobalValue>(U) &&
3511                      Visited.insert(U).second)
3512             Worklist.push_back(U);
3513         }
3514       }
3515     }
3516   }
3517 
3518   if (!BlockAddressUsers.empty()) {
3519     Vals.resize(BlockAddressUsers.size());
3520     for (auto I : llvm::enumerate(BlockAddressUsers))
3521       Vals[I.index()] = VE.getValueID(I.value());
3522     Stream.EmitRecord(bitc::FUNC_CODE_BLOCKADDR_USERS, Vals);
3523     Vals.clear();
3524   }
3525 
3526   // Emit names for all the instructions etc.
3527   if (auto *Symtab = F.getValueSymbolTable())
3528     writeFunctionLevelValueSymbolTable(*Symtab);
3529 
3530   if (NeedsMetadataAttachment)
3531     writeFunctionMetadataAttachment(F);
3532   if (VE.shouldPreserveUseListOrder())
3533     writeUseListBlock(&F);
3534   VE.purgeFunction();
3535   Stream.ExitBlock();
3536 }
3537 
3538 // Emit blockinfo, which defines the standard abbreviations etc.
3539 void ModuleBitcodeWriter::writeBlockInfo() {
3540   // We only want to emit block info records for blocks that have multiple
3541   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
3542   // Other blocks can define their abbrevs inline.
3543   Stream.EnterBlockInfoBlock();
3544 
3545   { // 8-bit fixed-width VST_CODE_ENTRY/VST_CODE_BBENTRY strings.
3546     auto Abbv = std::make_shared<BitCodeAbbrev>();
3547     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
3548     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3549     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3550     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3551     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3552         VST_ENTRY_8_ABBREV)
3553       llvm_unreachable("Unexpected abbrev ordering!");
3554   }
3555 
3556   { // 7-bit fixed width VST_CODE_ENTRY strings.
3557     auto Abbv = std::make_shared<BitCodeAbbrev>();
3558     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3559     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3560     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3561     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3562     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3563         VST_ENTRY_7_ABBREV)
3564       llvm_unreachable("Unexpected abbrev ordering!");
3565   }
3566   { // 6-bit char6 VST_CODE_ENTRY strings.
3567     auto Abbv = std::make_shared<BitCodeAbbrev>();
3568     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3569     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3570     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3571     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3572     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3573         VST_ENTRY_6_ABBREV)
3574       llvm_unreachable("Unexpected abbrev ordering!");
3575   }
3576   { // 6-bit char6 VST_CODE_BBENTRY strings.
3577     auto Abbv = std::make_shared<BitCodeAbbrev>();
3578     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
3579     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3580     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3581     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3582     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3583         VST_BBENTRY_6_ABBREV)
3584       llvm_unreachable("Unexpected abbrev ordering!");
3585   }
3586 
3587   { // SETTYPE abbrev for CONSTANTS_BLOCK.
3588     auto Abbv = std::make_shared<BitCodeAbbrev>();
3589     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
3590     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
3591                               VE.computeBitsRequiredForTypeIndicies()));
3592     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3593         CONSTANTS_SETTYPE_ABBREV)
3594       llvm_unreachable("Unexpected abbrev ordering!");
3595   }
3596 
3597   { // INTEGER abbrev for CONSTANTS_BLOCK.
3598     auto Abbv = std::make_shared<BitCodeAbbrev>();
3599     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
3600     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3601     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3602         CONSTANTS_INTEGER_ABBREV)
3603       llvm_unreachable("Unexpected abbrev ordering!");
3604   }
3605 
3606   { // CE_CAST abbrev for CONSTANTS_BLOCK.
3607     auto Abbv = std::make_shared<BitCodeAbbrev>();
3608     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
3609     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
3610     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
3611                               VE.computeBitsRequiredForTypeIndicies()));
3612     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
3613 
3614     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3615         CONSTANTS_CE_CAST_Abbrev)
3616       llvm_unreachable("Unexpected abbrev ordering!");
3617   }
3618   { // NULL abbrev for CONSTANTS_BLOCK.
3619     auto Abbv = std::make_shared<BitCodeAbbrev>();
3620     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
3621     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3622         CONSTANTS_NULL_Abbrev)
3623       llvm_unreachable("Unexpected abbrev ordering!");
3624   }
3625 
3626   // FIXME: This should only use space for first class types!
3627 
3628   { // INST_LOAD abbrev for FUNCTION_BLOCK.
3629     auto Abbv = std::make_shared<BitCodeAbbrev>();
3630     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
3631     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
3632     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
3633                               VE.computeBitsRequiredForTypeIndicies()));
3634     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
3635     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
3636     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3637         FUNCTION_INST_LOAD_ABBREV)
3638       llvm_unreachable("Unexpected abbrev ordering!");
3639   }
3640   { // INST_UNOP abbrev for FUNCTION_BLOCK.
3641     auto Abbv = std::make_shared<BitCodeAbbrev>();
3642     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3643     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3644     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3645     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3646         FUNCTION_INST_UNOP_ABBREV)
3647       llvm_unreachable("Unexpected abbrev ordering!");
3648   }
3649   { // INST_UNOP_FLAGS abbrev for FUNCTION_BLOCK.
3650     auto Abbv = std::make_shared<BitCodeAbbrev>();
3651     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3652     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3653     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3654     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3655     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3656         FUNCTION_INST_UNOP_FLAGS_ABBREV)
3657       llvm_unreachable("Unexpected abbrev ordering!");
3658   }
3659   { // INST_BINOP abbrev for FUNCTION_BLOCK.
3660     auto Abbv = std::make_shared<BitCodeAbbrev>();
3661     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3662     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3663     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3664     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3665     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3666         FUNCTION_INST_BINOP_ABBREV)
3667       llvm_unreachable("Unexpected abbrev ordering!");
3668   }
3669   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
3670     auto Abbv = std::make_shared<BitCodeAbbrev>();
3671     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3672     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3673     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3674     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3675     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3676     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3677         FUNCTION_INST_BINOP_FLAGS_ABBREV)
3678       llvm_unreachable("Unexpected abbrev ordering!");
3679   }
3680   { // INST_CAST abbrev for FUNCTION_BLOCK.
3681     auto Abbv = std::make_shared<BitCodeAbbrev>();
3682     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
3683     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
3684     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
3685                               VE.computeBitsRequiredForTypeIndicies()));
3686     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
3687     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3688         FUNCTION_INST_CAST_ABBREV)
3689       llvm_unreachable("Unexpected abbrev ordering!");
3690   }
3691   { // INST_CAST_FLAGS abbrev for FUNCTION_BLOCK.
3692     auto Abbv = std::make_shared<BitCodeAbbrev>();
3693     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
3694     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // OpVal
3695     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
3696                               VE.computeBitsRequiredForTypeIndicies()));
3697     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3698     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3699     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3700         FUNCTION_INST_CAST_FLAGS_ABBREV)
3701       llvm_unreachable("Unexpected abbrev ordering!");
3702   }
3703 
3704   { // INST_RET abbrev for FUNCTION_BLOCK.
3705     auto Abbv = std::make_shared<BitCodeAbbrev>();
3706     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3707     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3708         FUNCTION_INST_RET_VOID_ABBREV)
3709       llvm_unreachable("Unexpected abbrev ordering!");
3710   }
3711   { // INST_RET abbrev for FUNCTION_BLOCK.
3712     auto Abbv = std::make_shared<BitCodeAbbrev>();
3713     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3714     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
3715     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3716         FUNCTION_INST_RET_VAL_ABBREV)
3717       llvm_unreachable("Unexpected abbrev ordering!");
3718   }
3719   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
3720     auto Abbv = std::make_shared<BitCodeAbbrev>();
3721     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
3722     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3723         FUNCTION_INST_UNREACHABLE_ABBREV)
3724       llvm_unreachable("Unexpected abbrev ordering!");
3725   }
3726   {
3727     auto Abbv = std::make_shared<BitCodeAbbrev>();
3728     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_GEP));
3729     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
3730     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, // dest ty
3731                               Log2_32_Ceil(VE.getTypes().size() + 1)));
3732     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3733     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
3734     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3735         FUNCTION_INST_GEP_ABBREV)
3736       llvm_unreachable("Unexpected abbrev ordering!");
3737   }
3738 
3739   Stream.ExitBlock();
3740 }
3741 
3742 /// Write the module path strings, currently only used when generating
3743 /// a combined index file.
3744 void IndexBitcodeWriter::writeModStrings() {
3745   Stream.EnterSubblock(bitc::MODULE_STRTAB_BLOCK_ID, 3);
3746 
3747   // TODO: See which abbrev sizes we actually need to emit
3748 
3749   // 8-bit fixed-width MST_ENTRY strings.
3750   auto Abbv = std::make_shared<BitCodeAbbrev>();
3751   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3752   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3753   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3754   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3755   unsigned Abbrev8Bit = Stream.EmitAbbrev(std::move(Abbv));
3756 
3757   // 7-bit fixed width MST_ENTRY strings.
3758   Abbv = std::make_shared<BitCodeAbbrev>();
3759   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3760   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3761   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3762   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3763   unsigned Abbrev7Bit = Stream.EmitAbbrev(std::move(Abbv));
3764 
3765   // 6-bit char6 MST_ENTRY strings.
3766   Abbv = std::make_shared<BitCodeAbbrev>();
3767   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3768   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3769   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3770   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3771   unsigned Abbrev6Bit = Stream.EmitAbbrev(std::move(Abbv));
3772 
3773   // Module Hash, 160 bits SHA1. Optionally, emitted after each MST_CODE_ENTRY.
3774   Abbv = std::make_shared<BitCodeAbbrev>();
3775   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_HASH));
3776   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3777   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3778   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3779   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3780   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3781   unsigned AbbrevHash = Stream.EmitAbbrev(std::move(Abbv));
3782 
3783   SmallVector<unsigned, 64> Vals;
3784   forEachModule([&](const StringMapEntry<ModuleHash> &MPSE) {
3785     StringRef Key = MPSE.getKey();
3786     const auto &Hash = MPSE.getValue();
3787     StringEncoding Bits = getStringEncoding(Key);
3788     unsigned AbbrevToUse = Abbrev8Bit;
3789     if (Bits == SE_Char6)
3790       AbbrevToUse = Abbrev6Bit;
3791     else if (Bits == SE_Fixed7)
3792       AbbrevToUse = Abbrev7Bit;
3793 
3794     auto ModuleId = ModuleIdMap.size();
3795     ModuleIdMap[Key] = ModuleId;
3796     Vals.push_back(ModuleId);
3797     Vals.append(Key.begin(), Key.end());
3798 
3799     // Emit the finished record.
3800     Stream.EmitRecord(bitc::MST_CODE_ENTRY, Vals, AbbrevToUse);
3801 
3802     // Emit an optional hash for the module now
3803     if (llvm::any_of(Hash, [](uint32_t H) { return H; })) {
3804       Vals.assign(Hash.begin(), Hash.end());
3805       // Emit the hash record.
3806       Stream.EmitRecord(bitc::MST_CODE_HASH, Vals, AbbrevHash);
3807     }
3808 
3809     Vals.clear();
3810   });
3811   Stream.ExitBlock();
3812 }
3813 
3814 /// Write the function type metadata related records that need to appear before
3815 /// a function summary entry (whether per-module or combined).
3816 template <typename Fn>
3817 static void writeFunctionTypeMetadataRecords(BitstreamWriter &Stream,
3818                                              FunctionSummary *FS,
3819                                              Fn GetValueID) {
3820   if (!FS->type_tests().empty())
3821     Stream.EmitRecord(bitc::FS_TYPE_TESTS, FS->type_tests());
3822 
3823   SmallVector<uint64_t, 64> Record;
3824 
3825   auto WriteVFuncIdVec = [&](uint64_t Ty,
3826                              ArrayRef<FunctionSummary::VFuncId> VFs) {
3827     if (VFs.empty())
3828       return;
3829     Record.clear();
3830     for (auto &VF : VFs) {
3831       Record.push_back(VF.GUID);
3832       Record.push_back(VF.Offset);
3833     }
3834     Stream.EmitRecord(Ty, Record);
3835   };
3836 
3837   WriteVFuncIdVec(bitc::FS_TYPE_TEST_ASSUME_VCALLS,
3838                   FS->type_test_assume_vcalls());
3839   WriteVFuncIdVec(bitc::FS_TYPE_CHECKED_LOAD_VCALLS,
3840                   FS->type_checked_load_vcalls());
3841 
3842   auto WriteConstVCallVec = [&](uint64_t Ty,
3843                                 ArrayRef<FunctionSummary::ConstVCall> VCs) {
3844     for (auto &VC : VCs) {
3845       Record.clear();
3846       Record.push_back(VC.VFunc.GUID);
3847       Record.push_back(VC.VFunc.Offset);
3848       llvm::append_range(Record, VC.Args);
3849       Stream.EmitRecord(Ty, Record);
3850     }
3851   };
3852 
3853   WriteConstVCallVec(bitc::FS_TYPE_TEST_ASSUME_CONST_VCALL,
3854                      FS->type_test_assume_const_vcalls());
3855   WriteConstVCallVec(bitc::FS_TYPE_CHECKED_LOAD_CONST_VCALL,
3856                      FS->type_checked_load_const_vcalls());
3857 
3858   auto WriteRange = [&](ConstantRange Range) {
3859     Range = Range.sextOrTrunc(FunctionSummary::ParamAccess::RangeWidth);
3860     assert(Range.getLower().getNumWords() == 1);
3861     assert(Range.getUpper().getNumWords() == 1);
3862     emitSignedInt64(Record, *Range.getLower().getRawData());
3863     emitSignedInt64(Record, *Range.getUpper().getRawData());
3864   };
3865 
3866   if (!FS->paramAccesses().empty()) {
3867     Record.clear();
3868     for (auto &Arg : FS->paramAccesses()) {
3869       size_t UndoSize = Record.size();
3870       Record.push_back(Arg.ParamNo);
3871       WriteRange(Arg.Use);
3872       Record.push_back(Arg.Calls.size());
3873       for (auto &Call : Arg.Calls) {
3874         Record.push_back(Call.ParamNo);
3875         std::optional<unsigned> ValueID = GetValueID(Call.Callee);
3876         if (!ValueID) {
3877           // If ValueID is unknown we can't drop just this call, we must drop
3878           // entire parameter.
3879           Record.resize(UndoSize);
3880           break;
3881         }
3882         Record.push_back(*ValueID);
3883         WriteRange(Call.Offsets);
3884       }
3885     }
3886     if (!Record.empty())
3887       Stream.EmitRecord(bitc::FS_PARAM_ACCESS, Record);
3888   }
3889 }
3890 
3891 /// Collect type IDs from type tests used by function.
3892 static void
3893 getReferencedTypeIds(FunctionSummary *FS,
3894                      std::set<GlobalValue::GUID> &ReferencedTypeIds) {
3895   if (!FS->type_tests().empty())
3896     for (auto &TT : FS->type_tests())
3897       ReferencedTypeIds.insert(TT);
3898 
3899   auto GetReferencedTypesFromVFuncIdVec =
3900       [&](ArrayRef<FunctionSummary::VFuncId> VFs) {
3901         for (auto &VF : VFs)
3902           ReferencedTypeIds.insert(VF.GUID);
3903       };
3904 
3905   GetReferencedTypesFromVFuncIdVec(FS->type_test_assume_vcalls());
3906   GetReferencedTypesFromVFuncIdVec(FS->type_checked_load_vcalls());
3907 
3908   auto GetReferencedTypesFromConstVCallVec =
3909       [&](ArrayRef<FunctionSummary::ConstVCall> VCs) {
3910         for (auto &VC : VCs)
3911           ReferencedTypeIds.insert(VC.VFunc.GUID);
3912       };
3913 
3914   GetReferencedTypesFromConstVCallVec(FS->type_test_assume_const_vcalls());
3915   GetReferencedTypesFromConstVCallVec(FS->type_checked_load_const_vcalls());
3916 }
3917 
3918 static void writeWholeProgramDevirtResolutionByArg(
3919     SmallVector<uint64_t, 64> &NameVals, const std::vector<uint64_t> &args,
3920     const WholeProgramDevirtResolution::ByArg &ByArg) {
3921   NameVals.push_back(args.size());
3922   llvm::append_range(NameVals, args);
3923 
3924   NameVals.push_back(ByArg.TheKind);
3925   NameVals.push_back(ByArg.Info);
3926   NameVals.push_back(ByArg.Byte);
3927   NameVals.push_back(ByArg.Bit);
3928 }
3929 
3930 static void writeWholeProgramDevirtResolution(
3931     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3932     uint64_t Id, const WholeProgramDevirtResolution &Wpd) {
3933   NameVals.push_back(Id);
3934 
3935   NameVals.push_back(Wpd.TheKind);
3936   NameVals.push_back(StrtabBuilder.add(Wpd.SingleImplName));
3937   NameVals.push_back(Wpd.SingleImplName.size());
3938 
3939   NameVals.push_back(Wpd.ResByArg.size());
3940   for (auto &A : Wpd.ResByArg)
3941     writeWholeProgramDevirtResolutionByArg(NameVals, A.first, A.second);
3942 }
3943 
3944 static void writeTypeIdSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
3945                                      StringTableBuilder &StrtabBuilder,
3946                                      const std::string &Id,
3947                                      const TypeIdSummary &Summary) {
3948   NameVals.push_back(StrtabBuilder.add(Id));
3949   NameVals.push_back(Id.size());
3950 
3951   NameVals.push_back(Summary.TTRes.TheKind);
3952   NameVals.push_back(Summary.TTRes.SizeM1BitWidth);
3953   NameVals.push_back(Summary.TTRes.AlignLog2);
3954   NameVals.push_back(Summary.TTRes.SizeM1);
3955   NameVals.push_back(Summary.TTRes.BitMask);
3956   NameVals.push_back(Summary.TTRes.InlineBits);
3957 
3958   for (auto &W : Summary.WPDRes)
3959     writeWholeProgramDevirtResolution(NameVals, StrtabBuilder, W.first,
3960                                       W.second);
3961 }
3962 
3963 static void writeTypeIdCompatibleVtableSummaryRecord(
3964     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3965     const std::string &Id, const TypeIdCompatibleVtableInfo &Summary,
3966     ValueEnumerator &VE) {
3967   NameVals.push_back(StrtabBuilder.add(Id));
3968   NameVals.push_back(Id.size());
3969 
3970   for (auto &P : Summary) {
3971     NameVals.push_back(P.AddressPointOffset);
3972     NameVals.push_back(VE.getValueID(P.VTableVI.getValue()));
3973   }
3974 }
3975 
3976 static void writeFunctionHeapProfileRecords(
3977     BitstreamWriter &Stream, FunctionSummary *FS, unsigned CallsiteAbbrev,
3978     unsigned AllocAbbrev, bool PerModule,
3979     std::function<unsigned(const ValueInfo &VI)> GetValueID,
3980     std::function<unsigned(unsigned)> GetStackIndex) {
3981   SmallVector<uint64_t> Record;
3982 
3983   for (auto &CI : FS->callsites()) {
3984     Record.clear();
3985     // Per module callsite clones should always have a single entry of
3986     // value 0.
3987     assert(!PerModule || (CI.Clones.size() == 1 && CI.Clones[0] == 0));
3988     Record.push_back(GetValueID(CI.Callee));
3989     if (!PerModule) {
3990       Record.push_back(CI.StackIdIndices.size());
3991       Record.push_back(CI.Clones.size());
3992     }
3993     for (auto Id : CI.StackIdIndices)
3994       Record.push_back(GetStackIndex(Id));
3995     if (!PerModule) {
3996       for (auto V : CI.Clones)
3997         Record.push_back(V);
3998     }
3999     Stream.EmitRecord(PerModule ? bitc::FS_PERMODULE_CALLSITE_INFO
4000                                 : bitc::FS_COMBINED_CALLSITE_INFO,
4001                       Record, CallsiteAbbrev);
4002   }
4003 
4004   for (auto &AI : FS->allocs()) {
4005     Record.clear();
4006     // Per module alloc versions should always have a single entry of
4007     // value 0.
4008     assert(!PerModule || (AI.Versions.size() == 1 && AI.Versions[0] == 0));
4009     if (!PerModule) {
4010       Record.push_back(AI.MIBs.size());
4011       Record.push_back(AI.Versions.size());
4012     }
4013     for (auto &MIB : AI.MIBs) {
4014       Record.push_back((uint8_t)MIB.AllocType);
4015       Record.push_back(MIB.StackIdIndices.size());
4016       for (auto Id : MIB.StackIdIndices)
4017         Record.push_back(GetStackIndex(Id));
4018     }
4019     if (!PerModule) {
4020       for (auto V : AI.Versions)
4021         Record.push_back(V);
4022     }
4023     Stream.EmitRecord(PerModule ? bitc::FS_PERMODULE_ALLOC_INFO
4024                                 : bitc::FS_COMBINED_ALLOC_INFO,
4025                       Record, AllocAbbrev);
4026   }
4027 }
4028 
4029 // Helper to emit a single function summary record.
4030 void ModuleBitcodeWriterBase::writePerModuleFunctionSummaryRecord(
4031     SmallVector<uint64_t, 64> &NameVals, GlobalValueSummary *Summary,
4032     unsigned ValueID, unsigned FSCallsRelBFAbbrev,
4033     unsigned FSCallsProfileAbbrev, unsigned CallsiteAbbrev,
4034     unsigned AllocAbbrev, const Function &F) {
4035   NameVals.push_back(ValueID);
4036 
4037   FunctionSummary *FS = cast<FunctionSummary>(Summary);
4038 
4039   writeFunctionTypeMetadataRecords(
4040       Stream, FS, [&](const ValueInfo &VI) -> std::optional<unsigned> {
4041         return {VE.getValueID(VI.getValue())};
4042       });
4043 
4044   writeFunctionHeapProfileRecords(
4045       Stream, FS, CallsiteAbbrev, AllocAbbrev,
4046       /*PerModule*/ true,
4047       /*GetValueId*/ [&](const ValueInfo &VI) { return getValueId(VI); },
4048       /*GetStackIndex*/ [&](unsigned I) { return I; });
4049 
4050   auto SpecialRefCnts = FS->specialRefCounts();
4051   NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
4052   NameVals.push_back(FS->instCount());
4053   NameVals.push_back(getEncodedFFlags(FS->fflags()));
4054   NameVals.push_back(FS->refs().size());
4055   NameVals.push_back(SpecialRefCnts.first);  // rorefcnt
4056   NameVals.push_back(SpecialRefCnts.second); // worefcnt
4057 
4058   for (auto &RI : FS->refs())
4059     NameVals.push_back(VE.getValueID(RI.getValue()));
4060 
4061   const bool UseRelBFRecord =
4062       WriteRelBFToSummary && !F.hasProfileData() &&
4063       ForceSummaryEdgesCold == FunctionSummary::FSHT_None;
4064   for (auto &ECI : FS->calls()) {
4065     NameVals.push_back(getValueId(ECI.first));
4066     if (UseRelBFRecord)
4067       NameVals.push_back(getEncodedRelBFCallEdgeInfo(ECI.second));
4068     else
4069       NameVals.push_back(getEncodedHotnessCallEdgeInfo(ECI.second));
4070   }
4071 
4072   unsigned FSAbbrev =
4073       (UseRelBFRecord ? FSCallsRelBFAbbrev : FSCallsProfileAbbrev);
4074   unsigned Code =
4075       (UseRelBFRecord ? bitc::FS_PERMODULE_RELBF : bitc::FS_PERMODULE_PROFILE);
4076 
4077   // Emit the finished record.
4078   Stream.EmitRecord(Code, NameVals, FSAbbrev);
4079   NameVals.clear();
4080 }
4081 
4082 // Collect the global value references in the given variable's initializer,
4083 // and emit them in a summary record.
4084 void ModuleBitcodeWriterBase::writeModuleLevelReferences(
4085     const GlobalVariable &V, SmallVector<uint64_t, 64> &NameVals,
4086     unsigned FSModRefsAbbrev, unsigned FSModVTableRefsAbbrev) {
4087   auto VI = Index->getValueInfo(V.getGUID());
4088   if (!VI || VI.getSummaryList().empty()) {
4089     // Only declarations should not have a summary (a declaration might however
4090     // have a summary if the def was in module level asm).
4091     assert(V.isDeclaration());
4092     return;
4093   }
4094   auto *Summary = VI.getSummaryList()[0].get();
4095   NameVals.push_back(VE.getValueID(&V));
4096   GlobalVarSummary *VS = cast<GlobalVarSummary>(Summary);
4097   NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
4098   NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
4099 
4100   auto VTableFuncs = VS->vTableFuncs();
4101   if (!VTableFuncs.empty())
4102     NameVals.push_back(VS->refs().size());
4103 
4104   unsigned SizeBeforeRefs = NameVals.size();
4105   for (auto &RI : VS->refs())
4106     NameVals.push_back(VE.getValueID(RI.getValue()));
4107   // Sort the refs for determinism output, the vector returned by FS->refs() has
4108   // been initialized from a DenseSet.
4109   llvm::sort(drop_begin(NameVals, SizeBeforeRefs));
4110 
4111   if (VTableFuncs.empty())
4112     Stream.EmitRecord(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS, NameVals,
4113                       FSModRefsAbbrev);
4114   else {
4115     // VTableFuncs pairs should already be sorted by offset.
4116     for (auto &P : VTableFuncs) {
4117       NameVals.push_back(VE.getValueID(P.FuncVI.getValue()));
4118       NameVals.push_back(P.VTableOffset);
4119     }
4120 
4121     Stream.EmitRecord(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS, NameVals,
4122                       FSModVTableRefsAbbrev);
4123   }
4124   NameVals.clear();
4125 }
4126 
4127 /// Emit the per-module summary section alongside the rest of
4128 /// the module's bitcode.
4129 void ModuleBitcodeWriterBase::writePerModuleGlobalValueSummary() {
4130   // By default we compile with ThinLTO if the module has a summary, but the
4131   // client can request full LTO with a module flag.
4132   bool IsThinLTO = true;
4133   if (auto *MD =
4134           mdconst::extract_or_null<ConstantInt>(M.getModuleFlag("ThinLTO")))
4135     IsThinLTO = MD->getZExtValue();
4136   Stream.EnterSubblock(IsThinLTO ? bitc::GLOBALVAL_SUMMARY_BLOCK_ID
4137                                  : bitc::FULL_LTO_GLOBALVAL_SUMMARY_BLOCK_ID,
4138                        4);
4139 
4140   Stream.EmitRecord(
4141       bitc::FS_VERSION,
4142       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
4143 
4144   // Write the index flags.
4145   uint64_t Flags = 0;
4146   // Bits 1-3 are set only in the combined index, skip them.
4147   if (Index->enableSplitLTOUnit())
4148     Flags |= 0x8;
4149   if (Index->hasUnifiedLTO())
4150     Flags |= 0x200;
4151 
4152   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Flags});
4153 
4154   if (Index->begin() == Index->end()) {
4155     Stream.ExitBlock();
4156     return;
4157   }
4158 
4159   for (const auto &GVI : valueIds()) {
4160     Stream.EmitRecord(bitc::FS_VALUE_GUID,
4161                       ArrayRef<uint64_t>{GVI.second, GVI.first});
4162   }
4163 
4164   if (!Index->stackIds().empty()) {
4165     auto StackIdAbbv = std::make_shared<BitCodeAbbrev>();
4166     StackIdAbbv->Add(BitCodeAbbrevOp(bitc::FS_STACK_IDS));
4167     // numids x stackid
4168     StackIdAbbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4169     StackIdAbbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4170     unsigned StackIdAbbvId = Stream.EmitAbbrev(std::move(StackIdAbbv));
4171     Stream.EmitRecord(bitc::FS_STACK_IDS, Index->stackIds(), StackIdAbbvId);
4172   }
4173 
4174   // Abbrev for FS_PERMODULE_PROFILE.
4175   auto Abbv = std::make_shared<BitCodeAbbrev>();
4176   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_PROFILE));
4177   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4178   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // flags
4179   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4180   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4181   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4182   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4183   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4184   // numrefs x valueid, n x (valueid, hotness+tailcall flags)
4185   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4186   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4187   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4188 
4189   // Abbrev for FS_PERMODULE_RELBF.
4190   Abbv = std::make_shared<BitCodeAbbrev>();
4191   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_RELBF));
4192   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4193   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4194   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4195   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4196   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4197   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4198   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4199   // numrefs x valueid, n x (valueid, rel_block_freq+tailcall])
4200   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4201   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4202   unsigned FSCallsRelBFAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4203 
4204   // Abbrev for FS_PERMODULE_GLOBALVAR_INIT_REFS.
4205   Abbv = std::make_shared<BitCodeAbbrev>();
4206   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS));
4207   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
4208   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
4209   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));  // valueids
4210   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4211   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4212 
4213   // Abbrev for FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS.
4214   Abbv = std::make_shared<BitCodeAbbrev>();
4215   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS));
4216   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
4217   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
4218   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numrefs
4219   // numrefs x valueid, n x (valueid , offset)
4220   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4221   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4222   unsigned FSModVTableRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4223 
4224   // Abbrev for FS_ALIAS.
4225   Abbv = std::make_shared<BitCodeAbbrev>();
4226   Abbv->Add(BitCodeAbbrevOp(bitc::FS_ALIAS));
4227   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4228   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4229   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4230   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4231 
4232   // Abbrev for FS_TYPE_ID_METADATA
4233   Abbv = std::make_shared<BitCodeAbbrev>();
4234   Abbv->Add(BitCodeAbbrevOp(bitc::FS_TYPE_ID_METADATA));
4235   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid strtab index
4236   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid length
4237   // n x (valueid , offset)
4238   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4239   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4240   unsigned TypeIdCompatibleVtableAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4241 
4242   Abbv = std::make_shared<BitCodeAbbrev>();
4243   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_CALLSITE_INFO));
4244   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
4245   // n x stackidindex
4246   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4247   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4248   unsigned CallsiteAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4249 
4250   Abbv = std::make_shared<BitCodeAbbrev>();
4251   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_ALLOC_INFO));
4252   // n x (alloc type, numstackids, numstackids x stackidindex)
4253   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4254   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4255   unsigned AllocAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4256 
4257   SmallVector<uint64_t, 64> NameVals;
4258   // Iterate over the list of functions instead of the Index to
4259   // ensure the ordering is stable.
4260   for (const Function &F : M) {
4261     // Summary emission does not support anonymous functions, they have to
4262     // renamed using the anonymous function renaming pass.
4263     if (!F.hasName())
4264       report_fatal_error("Unexpected anonymous function when writing summary");
4265 
4266     ValueInfo VI = Index->getValueInfo(F.getGUID());
4267     if (!VI || VI.getSummaryList().empty()) {
4268       // Only declarations should not have a summary (a declaration might
4269       // however have a summary if the def was in module level asm).
4270       assert(F.isDeclaration());
4271       continue;
4272     }
4273     auto *Summary = VI.getSummaryList()[0].get();
4274     writePerModuleFunctionSummaryRecord(
4275         NameVals, Summary, VE.getValueID(&F), FSCallsRelBFAbbrev,
4276         FSCallsProfileAbbrev, CallsiteAbbrev, AllocAbbrev, F);
4277   }
4278 
4279   // Capture references from GlobalVariable initializers, which are outside
4280   // of a function scope.
4281   for (const GlobalVariable &G : M.globals())
4282     writeModuleLevelReferences(G, NameVals, FSModRefsAbbrev,
4283                                FSModVTableRefsAbbrev);
4284 
4285   for (const GlobalAlias &A : M.aliases()) {
4286     auto *Aliasee = A.getAliaseeObject();
4287     // Skip ifunc and nameless functions which don't have an entry in the
4288     // summary.
4289     if (!Aliasee->hasName() || isa<GlobalIFunc>(Aliasee))
4290       continue;
4291     auto AliasId = VE.getValueID(&A);
4292     auto AliaseeId = VE.getValueID(Aliasee);
4293     NameVals.push_back(AliasId);
4294     auto *Summary = Index->getGlobalValueSummary(A);
4295     AliasSummary *AS = cast<AliasSummary>(Summary);
4296     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
4297     NameVals.push_back(AliaseeId);
4298     Stream.EmitRecord(bitc::FS_ALIAS, NameVals, FSAliasAbbrev);
4299     NameVals.clear();
4300   }
4301 
4302   for (auto &S : Index->typeIdCompatibleVtableMap()) {
4303     writeTypeIdCompatibleVtableSummaryRecord(NameVals, StrtabBuilder, S.first,
4304                                              S.second, VE);
4305     Stream.EmitRecord(bitc::FS_TYPE_ID_METADATA, NameVals,
4306                       TypeIdCompatibleVtableAbbrev);
4307     NameVals.clear();
4308   }
4309 
4310   if (Index->getBlockCount())
4311     Stream.EmitRecord(bitc::FS_BLOCK_COUNT,
4312                       ArrayRef<uint64_t>{Index->getBlockCount()});
4313 
4314   Stream.ExitBlock();
4315 }
4316 
4317 /// Emit the combined summary section into the combined index file.
4318 void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
4319   Stream.EnterSubblock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID, 4);
4320   Stream.EmitRecord(
4321       bitc::FS_VERSION,
4322       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
4323 
4324   // Write the index flags.
4325   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Index.getFlags()});
4326 
4327   for (const auto &GVI : valueIds()) {
4328     Stream.EmitRecord(bitc::FS_VALUE_GUID,
4329                       ArrayRef<uint64_t>{GVI.second, GVI.first});
4330   }
4331 
4332   if (!StackIdIndices.empty()) {
4333     auto StackIdAbbv = std::make_shared<BitCodeAbbrev>();
4334     StackIdAbbv->Add(BitCodeAbbrevOp(bitc::FS_STACK_IDS));
4335     // numids x stackid
4336     StackIdAbbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4337     StackIdAbbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4338     unsigned StackIdAbbvId = Stream.EmitAbbrev(std::move(StackIdAbbv));
4339     // Write the stack ids used by this index, which will be a subset of those in
4340     // the full index in the case of distributed indexes.
4341     std::vector<uint64_t> StackIds;
4342     for (auto &I : StackIdIndices)
4343       StackIds.push_back(Index.getStackIdAtIndex(I));
4344     Stream.EmitRecord(bitc::FS_STACK_IDS, StackIds, StackIdAbbvId);
4345   }
4346 
4347   // Abbrev for FS_COMBINED_PROFILE.
4348   auto Abbv = std::make_shared<BitCodeAbbrev>();
4349   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_PROFILE));
4350   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4351   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4352   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4353   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4354   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4355   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
4356   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4357   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4358   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4359   // numrefs x valueid, n x (valueid, hotness+tailcall flags)
4360   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4361   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4362   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4363 
4364   // Abbrev for FS_COMBINED_GLOBALVAR_INIT_REFS.
4365   Abbv = std::make_shared<BitCodeAbbrev>();
4366   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS));
4367   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4368   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4369   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4370   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));    // valueids
4371   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4372   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4373 
4374   // Abbrev for FS_COMBINED_ALIAS.
4375   Abbv = std::make_shared<BitCodeAbbrev>();
4376   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_ALIAS));
4377   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4378   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4379   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4380   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4381   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4382 
4383   Abbv = std::make_shared<BitCodeAbbrev>();
4384   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_CALLSITE_INFO));
4385   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
4386   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numstackindices
4387   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numver
4388   // numstackindices x stackidindex, numver x version
4389   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4390   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4391   unsigned CallsiteAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4392 
4393   Abbv = std::make_shared<BitCodeAbbrev>();
4394   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_ALLOC_INFO));
4395   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // nummib
4396   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numver
4397   // nummib x (alloc type, numstackids, numstackids x stackidindex),
4398   // numver x version
4399   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4400   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4401   unsigned AllocAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4402 
4403   // The aliases are emitted as a post-pass, and will point to the value
4404   // id of the aliasee. Save them in a vector for post-processing.
4405   SmallVector<AliasSummary *, 64> Aliases;
4406 
4407   // Save the value id for each summary for alias emission.
4408   DenseMap<const GlobalValueSummary *, unsigned> SummaryToValueIdMap;
4409 
4410   SmallVector<uint64_t, 64> NameVals;
4411 
4412   // Set that will be populated during call to writeFunctionTypeMetadataRecords
4413   // with the type ids referenced by this index file.
4414   std::set<GlobalValue::GUID> ReferencedTypeIds;
4415 
4416   // For local linkage, we also emit the original name separately
4417   // immediately after the record.
4418   auto MaybeEmitOriginalName = [&](GlobalValueSummary &S) {
4419     // We don't need to emit the original name if we are writing the index for
4420     // distributed backends (in which case ModuleToSummariesForIndex is
4421     // non-null). The original name is only needed during the thin link, since
4422     // for SamplePGO the indirect call targets for local functions have
4423     // have the original name annotated in profile.
4424     // Continue to emit it when writing out the entire combined index, which is
4425     // used in testing the thin link via llvm-lto.
4426     if (ModuleToSummariesForIndex || !GlobalValue::isLocalLinkage(S.linkage()))
4427       return;
4428     NameVals.push_back(S.getOriginalName());
4429     Stream.EmitRecord(bitc::FS_COMBINED_ORIGINAL_NAME, NameVals);
4430     NameVals.clear();
4431   };
4432 
4433   std::set<GlobalValue::GUID> DefOrUseGUIDs;
4434   forEachSummary([&](GVInfo I, bool IsAliasee) {
4435     GlobalValueSummary *S = I.second;
4436     assert(S);
4437     DefOrUseGUIDs.insert(I.first);
4438     for (const ValueInfo &VI : S->refs())
4439       DefOrUseGUIDs.insert(VI.getGUID());
4440 
4441     auto ValueId = getValueId(I.first);
4442     assert(ValueId);
4443     SummaryToValueIdMap[S] = *ValueId;
4444 
4445     // If this is invoked for an aliasee, we want to record the above
4446     // mapping, but then not emit a summary entry (if the aliasee is
4447     // to be imported, we will invoke this separately with IsAliasee=false).
4448     if (IsAliasee)
4449       return;
4450 
4451     if (auto *AS = dyn_cast<AliasSummary>(S)) {
4452       // Will process aliases as a post-pass because the reader wants all
4453       // global to be loaded first.
4454       Aliases.push_back(AS);
4455       return;
4456     }
4457 
4458     if (auto *VS = dyn_cast<GlobalVarSummary>(S)) {
4459       NameVals.push_back(*ValueId);
4460       assert(ModuleIdMap.count(VS->modulePath()));
4461       NameVals.push_back(ModuleIdMap[VS->modulePath()]);
4462       NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
4463       NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
4464       for (auto &RI : VS->refs()) {
4465         auto RefValueId = getValueId(RI.getGUID());
4466         if (!RefValueId)
4467           continue;
4468         NameVals.push_back(*RefValueId);
4469       }
4470 
4471       // Emit the finished record.
4472       Stream.EmitRecord(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS, NameVals,
4473                         FSModRefsAbbrev);
4474       NameVals.clear();
4475       MaybeEmitOriginalName(*S);
4476       return;
4477     }
4478 
4479     auto GetValueId = [&](const ValueInfo &VI) -> std::optional<unsigned> {
4480       if (!VI)
4481         return std::nullopt;
4482       return getValueId(VI.getGUID());
4483     };
4484 
4485     auto *FS = cast<FunctionSummary>(S);
4486     writeFunctionTypeMetadataRecords(Stream, FS, GetValueId);
4487     getReferencedTypeIds(FS, ReferencedTypeIds);
4488 
4489     writeFunctionHeapProfileRecords(
4490         Stream, FS, CallsiteAbbrev, AllocAbbrev,
4491         /*PerModule*/ false,
4492         /*GetValueId*/ [&](const ValueInfo &VI) -> unsigned {
4493           std::optional<unsigned> ValueID = GetValueId(VI);
4494           // This can happen in shared index files for distributed ThinLTO if
4495           // the callee function summary is not included. Record 0 which we
4496           // will have to deal with conservatively when doing any kind of
4497           // validation in the ThinLTO backends.
4498           if (!ValueID)
4499             return 0;
4500           return *ValueID;
4501         },
4502         /*GetStackIndex*/ [&](unsigned I) {
4503           // Get the corresponding index into the list of StackIdIndices
4504           // actually being written for this combined index (which may be a
4505           // subset in the case of distributed indexes).
4506           auto Lower = llvm::lower_bound(StackIdIndices, I);
4507           return std::distance(StackIdIndices.begin(), Lower);
4508         });
4509 
4510     NameVals.push_back(*ValueId);
4511     assert(ModuleIdMap.count(FS->modulePath()));
4512     NameVals.push_back(ModuleIdMap[FS->modulePath()]);
4513     NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
4514     NameVals.push_back(FS->instCount());
4515     NameVals.push_back(getEncodedFFlags(FS->fflags()));
4516     NameVals.push_back(FS->entryCount());
4517 
4518     // Fill in below
4519     NameVals.push_back(0); // numrefs
4520     NameVals.push_back(0); // rorefcnt
4521     NameVals.push_back(0); // worefcnt
4522 
4523     unsigned Count = 0, RORefCnt = 0, WORefCnt = 0;
4524     for (auto &RI : FS->refs()) {
4525       auto RefValueId = getValueId(RI.getGUID());
4526       if (!RefValueId)
4527         continue;
4528       NameVals.push_back(*RefValueId);
4529       if (RI.isReadOnly())
4530         RORefCnt++;
4531       else if (RI.isWriteOnly())
4532         WORefCnt++;
4533       Count++;
4534     }
4535     NameVals[6] = Count;
4536     NameVals[7] = RORefCnt;
4537     NameVals[8] = WORefCnt;
4538 
4539     for (auto &EI : FS->calls()) {
4540       // If this GUID doesn't have a value id, it doesn't have a function
4541       // summary and we don't need to record any calls to it.
4542       std::optional<unsigned> CallValueId = GetValueId(EI.first);
4543       if (!CallValueId)
4544         continue;
4545       NameVals.push_back(*CallValueId);
4546       NameVals.push_back(getEncodedHotnessCallEdgeInfo(EI.second));
4547     }
4548 
4549     // Emit the finished record.
4550     Stream.EmitRecord(bitc::FS_COMBINED_PROFILE, NameVals,
4551                       FSCallsProfileAbbrev);
4552     NameVals.clear();
4553     MaybeEmitOriginalName(*S);
4554   });
4555 
4556   for (auto *AS : Aliases) {
4557     auto AliasValueId = SummaryToValueIdMap[AS];
4558     assert(AliasValueId);
4559     NameVals.push_back(AliasValueId);
4560     assert(ModuleIdMap.count(AS->modulePath()));
4561     NameVals.push_back(ModuleIdMap[AS->modulePath()]);
4562     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
4563     auto AliaseeValueId = SummaryToValueIdMap[&AS->getAliasee()];
4564     assert(AliaseeValueId);
4565     NameVals.push_back(AliaseeValueId);
4566 
4567     // Emit the finished record.
4568     Stream.EmitRecord(bitc::FS_COMBINED_ALIAS, NameVals, FSAliasAbbrev);
4569     NameVals.clear();
4570     MaybeEmitOriginalName(*AS);
4571 
4572     if (auto *FS = dyn_cast<FunctionSummary>(&AS->getAliasee()))
4573       getReferencedTypeIds(FS, ReferencedTypeIds);
4574   }
4575 
4576   if (!Index.cfiFunctionDefs().empty()) {
4577     for (auto &S : Index.cfiFunctionDefs()) {
4578       if (DefOrUseGUIDs.count(
4579               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4580         NameVals.push_back(StrtabBuilder.add(S));
4581         NameVals.push_back(S.size());
4582       }
4583     }
4584     if (!NameVals.empty()) {
4585       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DEFS, NameVals);
4586       NameVals.clear();
4587     }
4588   }
4589 
4590   if (!Index.cfiFunctionDecls().empty()) {
4591     for (auto &S : Index.cfiFunctionDecls()) {
4592       if (DefOrUseGUIDs.count(
4593               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4594         NameVals.push_back(StrtabBuilder.add(S));
4595         NameVals.push_back(S.size());
4596       }
4597     }
4598     if (!NameVals.empty()) {
4599       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DECLS, NameVals);
4600       NameVals.clear();
4601     }
4602   }
4603 
4604   // Walk the GUIDs that were referenced, and write the
4605   // corresponding type id records.
4606   for (auto &T : ReferencedTypeIds) {
4607     auto TidIter = Index.typeIds().equal_range(T);
4608     for (auto It = TidIter.first; It != TidIter.second; ++It) {
4609       writeTypeIdSummaryRecord(NameVals, StrtabBuilder, It->second.first,
4610                                It->second.second);
4611       Stream.EmitRecord(bitc::FS_TYPE_ID, NameVals);
4612       NameVals.clear();
4613     }
4614   }
4615 
4616   if (Index.getBlockCount())
4617     Stream.EmitRecord(bitc::FS_BLOCK_COUNT,
4618                       ArrayRef<uint64_t>{Index.getBlockCount()});
4619 
4620   Stream.ExitBlock();
4621 }
4622 
4623 /// Create the "IDENTIFICATION_BLOCK_ID" containing a single string with the
4624 /// current llvm version, and a record for the epoch number.
4625 static void writeIdentificationBlock(BitstreamWriter &Stream) {
4626   Stream.EnterSubblock(bitc::IDENTIFICATION_BLOCK_ID, 5);
4627 
4628   // Write the "user readable" string identifying the bitcode producer
4629   auto Abbv = std::make_shared<BitCodeAbbrev>();
4630   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_STRING));
4631   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4632   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
4633   auto StringAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4634   writeStringRecord(Stream, bitc::IDENTIFICATION_CODE_STRING,
4635                     "LLVM" LLVM_VERSION_STRING, StringAbbrev);
4636 
4637   // Write the epoch version
4638   Abbv = std::make_shared<BitCodeAbbrev>();
4639   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_EPOCH));
4640   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
4641   auto EpochAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4642   constexpr std::array<unsigned, 1> Vals = {{bitc::BITCODE_CURRENT_EPOCH}};
4643   Stream.EmitRecord(bitc::IDENTIFICATION_CODE_EPOCH, Vals, EpochAbbrev);
4644   Stream.ExitBlock();
4645 }
4646 
4647 void ModuleBitcodeWriter::writeModuleHash(size_t BlockStartPos) {
4648   // Emit the module's hash.
4649   // MODULE_CODE_HASH: [5*i32]
4650   if (GenerateHash) {
4651     uint32_t Vals[5];
4652     Hasher.update(ArrayRef<uint8_t>((const uint8_t *)&(Buffer)[BlockStartPos],
4653                                     Buffer.size() - BlockStartPos));
4654     std::array<uint8_t, 20> Hash = Hasher.result();
4655     for (int Pos = 0; Pos < 20; Pos += 4) {
4656       Vals[Pos / 4] = support::endian::read32be(Hash.data() + Pos);
4657     }
4658 
4659     // Emit the finished record.
4660     Stream.EmitRecord(bitc::MODULE_CODE_HASH, Vals);
4661 
4662     if (ModHash)
4663       // Save the written hash value.
4664       llvm::copy(Vals, std::begin(*ModHash));
4665   }
4666 }
4667 
4668 void ModuleBitcodeWriter::write() {
4669   writeIdentificationBlock(Stream);
4670 
4671   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4672   size_t BlockStartPos = Buffer.size();
4673 
4674   writeModuleVersion();
4675 
4676   // Emit blockinfo, which defines the standard abbreviations etc.
4677   writeBlockInfo();
4678 
4679   // Emit information describing all of the types in the module.
4680   writeTypeTable();
4681 
4682   // Emit information about attribute groups.
4683   writeAttributeGroupTable();
4684 
4685   // Emit information about parameter attributes.
4686   writeAttributeTable();
4687 
4688   writeComdats();
4689 
4690   // Emit top-level description of module, including target triple, inline asm,
4691   // descriptors for global variables, and function prototype info.
4692   writeModuleInfo();
4693 
4694   // Emit constants.
4695   writeModuleConstants();
4696 
4697   // Emit metadata kind names.
4698   writeModuleMetadataKinds();
4699 
4700   // Emit metadata.
4701   writeModuleMetadata();
4702 
4703   // Emit module-level use-lists.
4704   if (VE.shouldPreserveUseListOrder())
4705     writeUseListBlock(nullptr);
4706 
4707   writeOperandBundleTags();
4708   writeSyncScopeNames();
4709 
4710   // Emit function bodies.
4711   DenseMap<const Function *, uint64_t> FunctionToBitcodeIndex;
4712   for (const Function &F : M)
4713     if (!F.isDeclaration())
4714       writeFunction(F, FunctionToBitcodeIndex);
4715 
4716   // Need to write after the above call to WriteFunction which populates
4717   // the summary information in the index.
4718   if (Index)
4719     writePerModuleGlobalValueSummary();
4720 
4721   writeGlobalValueSymbolTable(FunctionToBitcodeIndex);
4722 
4723   writeModuleHash(BlockStartPos);
4724 
4725   Stream.ExitBlock();
4726 }
4727 
4728 static void writeInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
4729                                uint32_t &Position) {
4730   support::endian::write32le(&Buffer[Position], Value);
4731   Position += 4;
4732 }
4733 
4734 /// If generating a bc file on darwin, we have to emit a
4735 /// header and trailer to make it compatible with the system archiver.  To do
4736 /// this we emit the following header, and then emit a trailer that pads the
4737 /// file out to be a multiple of 16 bytes.
4738 ///
4739 /// struct bc_header {
4740 ///   uint32_t Magic;         // 0x0B17C0DE
4741 ///   uint32_t Version;       // Version, currently always 0.
4742 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
4743 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
4744 ///   uint32_t CPUType;       // CPU specifier.
4745 ///   ... potentially more later ...
4746 /// };
4747 static void emitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
4748                                          const Triple &TT) {
4749   unsigned CPUType = ~0U;
4750 
4751   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
4752   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
4753   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
4754   // specific constants here because they are implicitly part of the Darwin ABI.
4755   enum {
4756     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
4757     DARWIN_CPU_TYPE_X86        = 7,
4758     DARWIN_CPU_TYPE_ARM        = 12,
4759     DARWIN_CPU_TYPE_POWERPC    = 18
4760   };
4761 
4762   Triple::ArchType Arch = TT.getArch();
4763   if (Arch == Triple::x86_64)
4764     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
4765   else if (Arch == Triple::x86)
4766     CPUType = DARWIN_CPU_TYPE_X86;
4767   else if (Arch == Triple::ppc)
4768     CPUType = DARWIN_CPU_TYPE_POWERPC;
4769   else if (Arch == Triple::ppc64)
4770     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
4771   else if (Arch == Triple::arm || Arch == Triple::thumb)
4772     CPUType = DARWIN_CPU_TYPE_ARM;
4773 
4774   // Traditional Bitcode starts after header.
4775   assert(Buffer.size() >= BWH_HeaderSize &&
4776          "Expected header size to be reserved");
4777   unsigned BCOffset = BWH_HeaderSize;
4778   unsigned BCSize = Buffer.size() - BWH_HeaderSize;
4779 
4780   // Write the magic and version.
4781   unsigned Position = 0;
4782   writeInt32ToBuffer(0x0B17C0DE, Buffer, Position);
4783   writeInt32ToBuffer(0, Buffer, Position); // Version.
4784   writeInt32ToBuffer(BCOffset, Buffer, Position);
4785   writeInt32ToBuffer(BCSize, Buffer, Position);
4786   writeInt32ToBuffer(CPUType, Buffer, Position);
4787 
4788   // If the file is not a multiple of 16 bytes, insert dummy padding.
4789   while (Buffer.size() & 15)
4790     Buffer.push_back(0);
4791 }
4792 
4793 /// Helper to write the header common to all bitcode files.
4794 static void writeBitcodeHeader(BitstreamWriter &Stream) {
4795   // Emit the file header.
4796   Stream.Emit((unsigned)'B', 8);
4797   Stream.Emit((unsigned)'C', 8);
4798   Stream.Emit(0x0, 4);
4799   Stream.Emit(0xC, 4);
4800   Stream.Emit(0xE, 4);
4801   Stream.Emit(0xD, 4);
4802 }
4803 
4804 BitcodeWriter::BitcodeWriter(SmallVectorImpl<char> &Buffer, raw_fd_stream *FS)
4805     : Buffer(Buffer), Stream(new BitstreamWriter(Buffer, FS, FlushThreshold)) {
4806   writeBitcodeHeader(*Stream);
4807 }
4808 
4809 BitcodeWriter::~BitcodeWriter() { assert(WroteStrtab); }
4810 
4811 void BitcodeWriter::writeBlob(unsigned Block, unsigned Record, StringRef Blob) {
4812   Stream->EnterSubblock(Block, 3);
4813 
4814   auto Abbv = std::make_shared<BitCodeAbbrev>();
4815   Abbv->Add(BitCodeAbbrevOp(Record));
4816   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
4817   auto AbbrevNo = Stream->EmitAbbrev(std::move(Abbv));
4818 
4819   Stream->EmitRecordWithBlob(AbbrevNo, ArrayRef<uint64_t>{Record}, Blob);
4820 
4821   Stream->ExitBlock();
4822 }
4823 
4824 void BitcodeWriter::writeSymtab() {
4825   assert(!WroteStrtab && !WroteSymtab);
4826 
4827   // If any module has module-level inline asm, we will require a registered asm
4828   // parser for the target so that we can create an accurate symbol table for
4829   // the module.
4830   for (Module *M : Mods) {
4831     if (M->getModuleInlineAsm().empty())
4832       continue;
4833 
4834     std::string Err;
4835     const Triple TT(M->getTargetTriple());
4836     const Target *T = TargetRegistry::lookupTarget(TT.str(), Err);
4837     if (!T || !T->hasMCAsmParser())
4838       return;
4839   }
4840 
4841   WroteSymtab = true;
4842   SmallVector<char, 0> Symtab;
4843   // The irsymtab::build function may be unable to create a symbol table if the
4844   // module is malformed (e.g. it contains an invalid alias). Writing a symbol
4845   // table is not required for correctness, but we still want to be able to
4846   // write malformed modules to bitcode files, so swallow the error.
4847   if (Error E = irsymtab::build(Mods, Symtab, StrtabBuilder, Alloc)) {
4848     consumeError(std::move(E));
4849     return;
4850   }
4851 
4852   writeBlob(bitc::SYMTAB_BLOCK_ID, bitc::SYMTAB_BLOB,
4853             {Symtab.data(), Symtab.size()});
4854 }
4855 
4856 void BitcodeWriter::writeStrtab() {
4857   assert(!WroteStrtab);
4858 
4859   std::vector<char> Strtab;
4860   StrtabBuilder.finalizeInOrder();
4861   Strtab.resize(StrtabBuilder.getSize());
4862   StrtabBuilder.write((uint8_t *)Strtab.data());
4863 
4864   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB,
4865             {Strtab.data(), Strtab.size()});
4866 
4867   WroteStrtab = true;
4868 }
4869 
4870 void BitcodeWriter::copyStrtab(StringRef Strtab) {
4871   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB, Strtab);
4872   WroteStrtab = true;
4873 }
4874 
4875 void BitcodeWriter::writeModule(const Module &M,
4876                                 bool ShouldPreserveUseListOrder,
4877                                 const ModuleSummaryIndex *Index,
4878                                 bool GenerateHash, ModuleHash *ModHash) {
4879   assert(!WroteStrtab);
4880 
4881   // The Mods vector is used by irsymtab::build, which requires non-const
4882   // Modules in case it needs to materialize metadata. But the bitcode writer
4883   // requires that the module is materialized, so we can cast to non-const here,
4884   // after checking that it is in fact materialized.
4885   assert(M.isMaterialized());
4886   Mods.push_back(const_cast<Module *>(&M));
4887 
4888   ModuleBitcodeWriter ModuleWriter(M, Buffer, StrtabBuilder, *Stream,
4889                                    ShouldPreserveUseListOrder, Index,
4890                                    GenerateHash, ModHash);
4891   ModuleWriter.write();
4892 }
4893 
4894 void BitcodeWriter::writeIndex(
4895     const ModuleSummaryIndex *Index,
4896     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4897   IndexBitcodeWriter IndexWriter(*Stream, StrtabBuilder, *Index,
4898                                  ModuleToSummariesForIndex);
4899   IndexWriter.write();
4900 }
4901 
4902 /// Write the specified module to the specified output stream.
4903 void llvm::WriteBitcodeToFile(const Module &M, raw_ostream &Out,
4904                               bool ShouldPreserveUseListOrder,
4905                               const ModuleSummaryIndex *Index,
4906                               bool GenerateHash, ModuleHash *ModHash) {
4907   SmallVector<char, 0> Buffer;
4908   Buffer.reserve(256*1024);
4909 
4910   // If this is darwin or another generic macho target, reserve space for the
4911   // header.
4912   Triple TT(M.getTargetTriple());
4913   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4914     Buffer.insert(Buffer.begin(), BWH_HeaderSize, 0);
4915 
4916   BitcodeWriter Writer(Buffer, dyn_cast<raw_fd_stream>(&Out));
4917   Writer.writeModule(M, ShouldPreserveUseListOrder, Index, GenerateHash,
4918                      ModHash);
4919   Writer.writeSymtab();
4920   Writer.writeStrtab();
4921 
4922   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4923     emitDarwinBCHeaderAndTrailer(Buffer, TT);
4924 
4925   // Write the generated bitstream to "Out".
4926   if (!Buffer.empty())
4927     Out.write((char *)&Buffer.front(), Buffer.size());
4928 }
4929 
4930 void IndexBitcodeWriter::write() {
4931   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4932 
4933   writeModuleVersion();
4934 
4935   // Write the module paths in the combined index.
4936   writeModStrings();
4937 
4938   // Write the summary combined index records.
4939   writeCombinedGlobalValueSummary();
4940 
4941   Stream.ExitBlock();
4942 }
4943 
4944 // Write the specified module summary index to the given raw output stream,
4945 // where it will be written in a new bitcode block. This is used when
4946 // writing the combined index file for ThinLTO. When writing a subset of the
4947 // index for a distributed backend, provide a \p ModuleToSummariesForIndex map.
4948 void llvm::writeIndexToFile(
4949     const ModuleSummaryIndex &Index, raw_ostream &Out,
4950     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4951   SmallVector<char, 0> Buffer;
4952   Buffer.reserve(256 * 1024);
4953 
4954   BitcodeWriter Writer(Buffer);
4955   Writer.writeIndex(&Index, ModuleToSummariesForIndex);
4956   Writer.writeStrtab();
4957 
4958   Out.write((char *)&Buffer.front(), Buffer.size());
4959 }
4960 
4961 namespace {
4962 
4963 /// Class to manage the bitcode writing for a thin link bitcode file.
4964 class ThinLinkBitcodeWriter : public ModuleBitcodeWriterBase {
4965   /// ModHash is for use in ThinLTO incremental build, generated while writing
4966   /// the module bitcode file.
4967   const ModuleHash *ModHash;
4968 
4969 public:
4970   ThinLinkBitcodeWriter(const Module &M, StringTableBuilder &StrtabBuilder,
4971                         BitstreamWriter &Stream,
4972                         const ModuleSummaryIndex &Index,
4973                         const ModuleHash &ModHash)
4974       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
4975                                 /*ShouldPreserveUseListOrder=*/false, &Index),
4976         ModHash(&ModHash) {}
4977 
4978   void write();
4979 
4980 private:
4981   void writeSimplifiedModuleInfo();
4982 };
4983 
4984 } // end anonymous namespace
4985 
4986 // This function writes a simpilified module info for thin link bitcode file.
4987 // It only contains the source file name along with the name(the offset and
4988 // size in strtab) and linkage for global values. For the global value info
4989 // entry, in order to keep linkage at offset 5, there are three zeros used
4990 // as padding.
4991 void ThinLinkBitcodeWriter::writeSimplifiedModuleInfo() {
4992   SmallVector<unsigned, 64> Vals;
4993   // Emit the module's source file name.
4994   {
4995     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
4996     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
4997     if (Bits == SE_Char6)
4998       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
4999     else if (Bits == SE_Fixed7)
5000       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
5001 
5002     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
5003     auto Abbv = std::make_shared<BitCodeAbbrev>();
5004     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
5005     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
5006     Abbv->Add(AbbrevOpToUse);
5007     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
5008 
5009     for (const auto P : M.getSourceFileName())
5010       Vals.push_back((unsigned char)P);
5011 
5012     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
5013     Vals.clear();
5014   }
5015 
5016   // Emit the global variable information.
5017   for (const GlobalVariable &GV : M.globals()) {
5018     // GLOBALVAR: [strtab offset, strtab size, 0, 0, 0, linkage]
5019     Vals.push_back(StrtabBuilder.add(GV.getName()));
5020     Vals.push_back(GV.getName().size());
5021     Vals.push_back(0);
5022     Vals.push_back(0);
5023     Vals.push_back(0);
5024     Vals.push_back(getEncodedLinkage(GV));
5025 
5026     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals);
5027     Vals.clear();
5028   }
5029 
5030   // Emit the function proto information.
5031   for (const Function &F : M) {
5032     // FUNCTION:  [strtab offset, strtab size, 0, 0, 0, linkage]
5033     Vals.push_back(StrtabBuilder.add(F.getName()));
5034     Vals.push_back(F.getName().size());
5035     Vals.push_back(0);
5036     Vals.push_back(0);
5037     Vals.push_back(0);
5038     Vals.push_back(getEncodedLinkage(F));
5039 
5040     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals);
5041     Vals.clear();
5042   }
5043 
5044   // Emit the alias information.
5045   for (const GlobalAlias &A : M.aliases()) {
5046     // ALIAS: [strtab offset, strtab size, 0, 0, 0, linkage]
5047     Vals.push_back(StrtabBuilder.add(A.getName()));
5048     Vals.push_back(A.getName().size());
5049     Vals.push_back(0);
5050     Vals.push_back(0);
5051     Vals.push_back(0);
5052     Vals.push_back(getEncodedLinkage(A));
5053 
5054     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals);
5055     Vals.clear();
5056   }
5057 
5058   // Emit the ifunc information.
5059   for (const GlobalIFunc &I : M.ifuncs()) {
5060     // IFUNC: [strtab offset, strtab size, 0, 0, 0, linkage]
5061     Vals.push_back(StrtabBuilder.add(I.getName()));
5062     Vals.push_back(I.getName().size());
5063     Vals.push_back(0);
5064     Vals.push_back(0);
5065     Vals.push_back(0);
5066     Vals.push_back(getEncodedLinkage(I));
5067 
5068     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
5069     Vals.clear();
5070   }
5071 }
5072 
5073 void ThinLinkBitcodeWriter::write() {
5074   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
5075 
5076   writeModuleVersion();
5077 
5078   writeSimplifiedModuleInfo();
5079 
5080   writePerModuleGlobalValueSummary();
5081 
5082   // Write module hash.
5083   Stream.EmitRecord(bitc::MODULE_CODE_HASH, ArrayRef<uint32_t>(*ModHash));
5084 
5085   Stream.ExitBlock();
5086 }
5087 
5088 void BitcodeWriter::writeThinLinkBitcode(const Module &M,
5089                                          const ModuleSummaryIndex &Index,
5090                                          const ModuleHash &ModHash) {
5091   assert(!WroteStrtab);
5092 
5093   // The Mods vector is used by irsymtab::build, which requires non-const
5094   // Modules in case it needs to materialize metadata. But the bitcode writer
5095   // requires that the module is materialized, so we can cast to non-const here,
5096   // after checking that it is in fact materialized.
5097   assert(M.isMaterialized());
5098   Mods.push_back(const_cast<Module *>(&M));
5099 
5100   ThinLinkBitcodeWriter ThinLinkWriter(M, StrtabBuilder, *Stream, Index,
5101                                        ModHash);
5102   ThinLinkWriter.write();
5103 }
5104 
5105 // Write the specified thin link bitcode file to the given raw output stream,
5106 // where it will be written in a new bitcode block. This is used when
5107 // writing the per-module index file for ThinLTO.
5108 void llvm::writeThinLinkBitcodeToFile(const Module &M, raw_ostream &Out,
5109                                       const ModuleSummaryIndex &Index,
5110                                       const ModuleHash &ModHash) {
5111   SmallVector<char, 0> Buffer;
5112   Buffer.reserve(256 * 1024);
5113 
5114   BitcodeWriter Writer(Buffer);
5115   Writer.writeThinLinkBitcode(M, Index, ModHash);
5116   Writer.writeSymtab();
5117   Writer.writeStrtab();
5118 
5119   Out.write((char *)&Buffer.front(), Buffer.size());
5120 }
5121 
5122 static const char *getSectionNameForBitcode(const Triple &T) {
5123   switch (T.getObjectFormat()) {
5124   case Triple::MachO:
5125     return "__LLVM,__bitcode";
5126   case Triple::COFF:
5127   case Triple::ELF:
5128   case Triple::Wasm:
5129   case Triple::UnknownObjectFormat:
5130     return ".llvmbc";
5131   case Triple::GOFF:
5132     llvm_unreachable("GOFF is not yet implemented");
5133     break;
5134   case Triple::SPIRV:
5135     llvm_unreachable("SPIRV is not yet implemented");
5136     break;
5137   case Triple::XCOFF:
5138     llvm_unreachable("XCOFF is not yet implemented");
5139     break;
5140   case Triple::DXContainer:
5141     llvm_unreachable("DXContainer is not yet implemented");
5142     break;
5143   }
5144   llvm_unreachable("Unimplemented ObjectFormatType");
5145 }
5146 
5147 static const char *getSectionNameForCommandline(const Triple &T) {
5148   switch (T.getObjectFormat()) {
5149   case Triple::MachO:
5150     return "__LLVM,__cmdline";
5151   case Triple::COFF:
5152   case Triple::ELF:
5153   case Triple::Wasm:
5154   case Triple::UnknownObjectFormat:
5155     return ".llvmcmd";
5156   case Triple::GOFF:
5157     llvm_unreachable("GOFF is not yet implemented");
5158     break;
5159   case Triple::SPIRV:
5160     llvm_unreachable("SPIRV is not yet implemented");
5161     break;
5162   case Triple::XCOFF:
5163     llvm_unreachable("XCOFF is not yet implemented");
5164     break;
5165   case Triple::DXContainer:
5166     llvm_unreachable("DXC is not yet implemented");
5167     break;
5168   }
5169   llvm_unreachable("Unimplemented ObjectFormatType");
5170 }
5171 
5172 void llvm::embedBitcodeInModule(llvm::Module &M, llvm::MemoryBufferRef Buf,
5173                                 bool EmbedBitcode, bool EmbedCmdline,
5174                                 const std::vector<uint8_t> &CmdArgs) {
5175   // Save llvm.compiler.used and remove it.
5176   SmallVector<Constant *, 2> UsedArray;
5177   SmallVector<GlobalValue *, 4> UsedGlobals;
5178   Type *UsedElementType = PointerType::getUnqual(M.getContext());
5179   GlobalVariable *Used = collectUsedGlobalVariables(M, UsedGlobals, true);
5180   for (auto *GV : UsedGlobals) {
5181     if (GV->getName() != "llvm.embedded.module" &&
5182         GV->getName() != "llvm.cmdline")
5183       UsedArray.push_back(
5184           ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
5185   }
5186   if (Used)
5187     Used->eraseFromParent();
5188 
5189   // Embed the bitcode for the llvm module.
5190   std::string Data;
5191   ArrayRef<uint8_t> ModuleData;
5192   Triple T(M.getTargetTriple());
5193 
5194   if (EmbedBitcode) {
5195     if (Buf.getBufferSize() == 0 ||
5196         !isBitcode((const unsigned char *)Buf.getBufferStart(),
5197                    (const unsigned char *)Buf.getBufferEnd())) {
5198       // If the input is LLVM Assembly, bitcode is produced by serializing
5199       // the module. Use-lists order need to be preserved in this case.
5200       llvm::raw_string_ostream OS(Data);
5201       llvm::WriteBitcodeToFile(M, OS, /* ShouldPreserveUseListOrder */ true);
5202       ModuleData =
5203           ArrayRef<uint8_t>((const uint8_t *)OS.str().data(), OS.str().size());
5204     } else
5205       // If the input is LLVM bitcode, write the input byte stream directly.
5206       ModuleData = ArrayRef<uint8_t>((const uint8_t *)Buf.getBufferStart(),
5207                                      Buf.getBufferSize());
5208   }
5209   llvm::Constant *ModuleConstant =
5210       llvm::ConstantDataArray::get(M.getContext(), ModuleData);
5211   llvm::GlobalVariable *GV = new llvm::GlobalVariable(
5212       M, ModuleConstant->getType(), true, llvm::GlobalValue::PrivateLinkage,
5213       ModuleConstant);
5214   GV->setSection(getSectionNameForBitcode(T));
5215   // Set alignment to 1 to prevent padding between two contributions from input
5216   // sections after linking.
5217   GV->setAlignment(Align(1));
5218   UsedArray.push_back(
5219       ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
5220   if (llvm::GlobalVariable *Old =
5221           M.getGlobalVariable("llvm.embedded.module", true)) {
5222     assert(Old->hasZeroLiveUses() &&
5223            "llvm.embedded.module can only be used once in llvm.compiler.used");
5224     GV->takeName(Old);
5225     Old->eraseFromParent();
5226   } else {
5227     GV->setName("llvm.embedded.module");
5228   }
5229 
5230   // Skip if only bitcode needs to be embedded.
5231   if (EmbedCmdline) {
5232     // Embed command-line options.
5233     ArrayRef<uint8_t> CmdData(const_cast<uint8_t *>(CmdArgs.data()),
5234                               CmdArgs.size());
5235     llvm::Constant *CmdConstant =
5236         llvm::ConstantDataArray::get(M.getContext(), CmdData);
5237     GV = new llvm::GlobalVariable(M, CmdConstant->getType(), true,
5238                                   llvm::GlobalValue::PrivateLinkage,
5239                                   CmdConstant);
5240     GV->setSection(getSectionNameForCommandline(T));
5241     GV->setAlignment(Align(1));
5242     UsedArray.push_back(
5243         ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
5244     if (llvm::GlobalVariable *Old = M.getGlobalVariable("llvm.cmdline", true)) {
5245       assert(Old->hasZeroLiveUses() &&
5246              "llvm.cmdline can only be used once in llvm.compiler.used");
5247       GV->takeName(Old);
5248       Old->eraseFromParent();
5249     } else {
5250       GV->setName("llvm.cmdline");
5251     }
5252   }
5253 
5254   if (UsedArray.empty())
5255     return;
5256 
5257   // Recreate llvm.compiler.used.
5258   ArrayType *ATy = ArrayType::get(UsedElementType, UsedArray.size());
5259   auto *NewUsed = new GlobalVariable(
5260       M, ATy, false, llvm::GlobalValue::AppendingLinkage,
5261       llvm::ConstantArray::get(ATy, UsedArray), "llvm.compiler.used");
5262   NewUsed->setSection("llvm.metadata");
5263 }
5264