xref: /llvm-project/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp (revision f6617d65e496823c748236cdbe8e42bf4c8d8a55)
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/ConstantRangeList.h"
37 #include "llvm/IR/Constants.h"
38 #include "llvm/IR/DebugInfoMetadata.h"
39 #include "llvm/IR/DebugLoc.h"
40 #include "llvm/IR/DerivedTypes.h"
41 #include "llvm/IR/Function.h"
42 #include "llvm/IR/GlobalAlias.h"
43 #include "llvm/IR/GlobalIFunc.h"
44 #include "llvm/IR/GlobalObject.h"
45 #include "llvm/IR/GlobalValue.h"
46 #include "llvm/IR/GlobalVariable.h"
47 #include "llvm/IR/InlineAsm.h"
48 #include "llvm/IR/InstrTypes.h"
49 #include "llvm/IR/Instruction.h"
50 #include "llvm/IR/Instructions.h"
51 #include "llvm/IR/LLVMContext.h"
52 #include "llvm/IR/Metadata.h"
53 #include "llvm/IR/Module.h"
54 #include "llvm/IR/ModuleSummaryIndex.h"
55 #include "llvm/IR/Operator.h"
56 #include "llvm/IR/Type.h"
57 #include "llvm/IR/UseListOrder.h"
58 #include "llvm/IR/Value.h"
59 #include "llvm/IR/ValueSymbolTable.h"
60 #include "llvm/MC/StringTableBuilder.h"
61 #include "llvm/MC/TargetRegistry.h"
62 #include "llvm/Object/IRSymtab.h"
63 #include "llvm/Support/AtomicOrdering.h"
64 #include "llvm/Support/Casting.h"
65 #include "llvm/Support/CommandLine.h"
66 #include "llvm/Support/Endian.h"
67 #include "llvm/Support/Error.h"
68 #include "llvm/Support/ErrorHandling.h"
69 #include "llvm/Support/MathExtras.h"
70 #include "llvm/Support/SHA1.h"
71 #include "llvm/Support/raw_ostream.h"
72 #include "llvm/TargetParser/Triple.h"
73 #include <algorithm>
74 #include <cassert>
75 #include <cstddef>
76 #include <cstdint>
77 #include <iterator>
78 #include <map>
79 #include <memory>
80 #include <optional>
81 #include <string>
82 #include <utility>
83 #include <vector>
84 
85 using namespace llvm;
86 
87 static cl::opt<unsigned>
88     IndexThreshold("bitcode-mdindex-threshold", cl::Hidden, cl::init(25),
89                    cl::desc("Number of metadatas above which we emit an index "
90                             "to enable lazy-loading"));
91 static cl::opt<uint32_t> FlushThreshold(
92     "bitcode-flush-threshold", cl::Hidden, cl::init(512),
93     cl::desc("The threshold (unit M) for flushing LLVM bitcode."));
94 
95 static cl::opt<bool> WriteRelBFToSummary(
96     "write-relbf-to-summary", cl::Hidden, cl::init(false),
97     cl::desc("Write relative block frequency to function summary "));
98 
99 namespace llvm {
100 extern FunctionSummary::ForceSummaryHotnessType ForceSummaryEdgesCold;
101 }
102 
103 extern bool WriteNewDbgInfoFormatToBitcode;
104 extern llvm::cl::opt<bool> UseNewDbgInfoFormat;
105 
106 namespace {
107 
108 /// These are manifest constants used by the bitcode writer. They do not need to
109 /// be kept in sync with the reader, but need to be consistent within this file.
110 enum {
111   // VALUE_SYMTAB_BLOCK abbrev id's.
112   VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
113   VST_ENTRY_7_ABBREV,
114   VST_ENTRY_6_ABBREV,
115   VST_BBENTRY_6_ABBREV,
116 
117   // CONSTANTS_BLOCK abbrev id's.
118   CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
119   CONSTANTS_INTEGER_ABBREV,
120   CONSTANTS_CE_CAST_Abbrev,
121   CONSTANTS_NULL_Abbrev,
122 
123   // FUNCTION_BLOCK abbrev id's.
124   FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
125   FUNCTION_INST_UNOP_ABBREV,
126   FUNCTION_INST_UNOP_FLAGS_ABBREV,
127   FUNCTION_INST_BINOP_ABBREV,
128   FUNCTION_INST_BINOP_FLAGS_ABBREV,
129   FUNCTION_INST_CAST_ABBREV,
130   FUNCTION_INST_CAST_FLAGS_ABBREV,
131   FUNCTION_INST_RET_VOID_ABBREV,
132   FUNCTION_INST_RET_VAL_ABBREV,
133   FUNCTION_INST_UNREACHABLE_ABBREV,
134   FUNCTION_INST_GEP_ABBREV,
135   FUNCTION_DEBUG_RECORD_VALUE_ABBREV,
136 };
137 
138 /// Abstract class to manage the bitcode writing, subclassed for each bitcode
139 /// file type.
140 class BitcodeWriterBase {
141 protected:
142   /// The stream created and owned by the client.
143   BitstreamWriter &Stream;
144 
145   StringTableBuilder &StrtabBuilder;
146 
147 public:
148   /// Constructs a BitcodeWriterBase object that writes to the provided
149   /// \p Stream.
150   BitcodeWriterBase(BitstreamWriter &Stream, StringTableBuilder &StrtabBuilder)
151       : Stream(Stream), StrtabBuilder(StrtabBuilder) {}
152 
153 protected:
154   void writeModuleVersion();
155 };
156 
157 void BitcodeWriterBase::writeModuleVersion() {
158   // VERSION: [version#]
159   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, ArrayRef<uint64_t>{2});
160 }
161 
162 /// Base class to manage the module bitcode writing, currently subclassed for
163 /// ModuleBitcodeWriter and ThinLinkBitcodeWriter.
164 class ModuleBitcodeWriterBase : public BitcodeWriterBase {
165 protected:
166   /// The Module to write to bitcode.
167   const Module &M;
168 
169   /// Enumerates ids for all values in the module.
170   ValueEnumerator VE;
171 
172   /// Optional per-module index to write for ThinLTO.
173   const ModuleSummaryIndex *Index;
174 
175   /// Map that holds the correspondence between GUIDs in the summary index,
176   /// that came from indirect call profiles, and a value id generated by this
177   /// class to use in the VST and summary block records.
178   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
179 
180   /// Tracks the last value id recorded in the GUIDToValueMap.
181   unsigned GlobalValueId;
182 
183   /// Saves the offset of the VSTOffset record that must eventually be
184   /// backpatched with the offset of the actual VST.
185   uint64_t VSTOffsetPlaceholder = 0;
186 
187 public:
188   /// Constructs a ModuleBitcodeWriterBase object for the given Module,
189   /// writing to the provided \p Buffer.
190   ModuleBitcodeWriterBase(const Module &M, StringTableBuilder &StrtabBuilder,
191                           BitstreamWriter &Stream,
192                           bool ShouldPreserveUseListOrder,
193                           const ModuleSummaryIndex *Index)
194       : BitcodeWriterBase(Stream, StrtabBuilder), M(M),
195         VE(M, ShouldPreserveUseListOrder), Index(Index) {
196     // Assign ValueIds to any callee values in the index that came from
197     // indirect call profiles and were recorded as a GUID not a Value*
198     // (which would have been assigned an ID by the ValueEnumerator).
199     // The starting ValueId is just after the number of values in the
200     // ValueEnumerator, so that they can be emitted in the VST.
201     GlobalValueId = VE.getValues().size();
202     if (!Index)
203       return;
204     for (const auto &GUIDSummaryLists : *Index)
205       // Examine all summaries for this GUID.
206       for (auto &Summary : GUIDSummaryLists.second.SummaryList)
207         if (auto FS = dyn_cast<FunctionSummary>(Summary.get())) {
208           // For each call in the function summary, see if the call
209           // is to a GUID (which means it is for an indirect call,
210           // otherwise we would have a Value for it). If so, synthesize
211           // a value id.
212           for (auto &CallEdge : FS->calls())
213             if (!CallEdge.first.haveGVs() || !CallEdge.first.getValue())
214               assignValueId(CallEdge.first.getGUID());
215 
216           // For each referenced variables in the function summary, see if the
217           // variable is represented by a GUID (as opposed to a symbol to
218           // declarations or definitions in the module). If so, synthesize a
219           // value id.
220           for (auto &RefEdge : FS->refs())
221             if (!RefEdge.haveGVs() || !RefEdge.getValue())
222               assignValueId(RefEdge.getGUID());
223         }
224   }
225 
226 protected:
227   void writePerModuleGlobalValueSummary();
228 
229 private:
230   void writePerModuleFunctionSummaryRecord(
231       SmallVector<uint64_t, 64> &NameVals, GlobalValueSummary *Summary,
232       unsigned ValueID, unsigned FSCallsAbbrev, unsigned FSCallsProfileAbbrev,
233       unsigned CallsiteAbbrev, unsigned AllocAbbrev, const Function &F);
234   void writeModuleLevelReferences(const GlobalVariable &V,
235                                   SmallVector<uint64_t, 64> &NameVals,
236                                   unsigned FSModRefsAbbrev,
237                                   unsigned FSModVTableRefsAbbrev);
238 
239   void assignValueId(GlobalValue::GUID ValGUID) {
240     GUIDToValueIdMap[ValGUID] = ++GlobalValueId;
241   }
242 
243   unsigned getValueId(GlobalValue::GUID ValGUID) {
244     const auto &VMI = GUIDToValueIdMap.find(ValGUID);
245     // Expect that any GUID value had a value Id assigned by an
246     // earlier call to assignValueId.
247     assert(VMI != GUIDToValueIdMap.end() &&
248            "GUID does not have assigned value Id");
249     return VMI->second;
250   }
251 
252   // Helper to get the valueId for the type of value recorded in VI.
253   unsigned getValueId(ValueInfo VI) {
254     if (!VI.haveGVs() || !VI.getValue())
255       return getValueId(VI.getGUID());
256     return VE.getValueID(VI.getValue());
257   }
258 
259   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
260 };
261 
262 /// Class to manage the bitcode writing for a module.
263 class ModuleBitcodeWriter : public ModuleBitcodeWriterBase {
264   /// True if a module hash record should be written.
265   bool GenerateHash;
266 
267   /// If non-null, when GenerateHash is true, the resulting hash is written
268   /// into ModHash.
269   ModuleHash *ModHash;
270 
271   SHA1 Hasher;
272 
273   /// The start bit of the identification block.
274   uint64_t BitcodeStartBit;
275 
276 public:
277   /// Constructs a ModuleBitcodeWriter object for the given Module,
278   /// writing to the provided \p Buffer.
279   ModuleBitcodeWriter(const Module &M, StringTableBuilder &StrtabBuilder,
280                       BitstreamWriter &Stream, bool ShouldPreserveUseListOrder,
281                       const ModuleSummaryIndex *Index, bool GenerateHash,
282                       ModuleHash *ModHash = nullptr)
283       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
284                                 ShouldPreserveUseListOrder, Index),
285         GenerateHash(GenerateHash), ModHash(ModHash),
286         BitcodeStartBit(Stream.GetCurrentBitNo()) {}
287 
288   /// Emit the current module to the bitstream.
289   void write();
290 
291 private:
292   uint64_t bitcodeStartBit() { return BitcodeStartBit; }
293 
294   size_t addToStrtab(StringRef Str);
295 
296   void writeAttributeGroupTable();
297   void writeAttributeTable();
298   void writeTypeTable();
299   void writeComdats();
300   void writeValueSymbolTableForwardDecl();
301   void writeModuleInfo();
302   void writeValueAsMetadata(const ValueAsMetadata *MD,
303                             SmallVectorImpl<uint64_t> &Record);
304   void writeMDTuple(const MDTuple *N, SmallVectorImpl<uint64_t> &Record,
305                     unsigned Abbrev);
306   unsigned createDILocationAbbrev();
307   void writeDILocation(const DILocation *N, SmallVectorImpl<uint64_t> &Record,
308                        unsigned &Abbrev);
309   unsigned createGenericDINodeAbbrev();
310   void writeGenericDINode(const GenericDINode *N,
311                           SmallVectorImpl<uint64_t> &Record, unsigned &Abbrev);
312   void writeDISubrange(const DISubrange *N, SmallVectorImpl<uint64_t> &Record,
313                        unsigned Abbrev);
314   void writeDIGenericSubrange(const DIGenericSubrange *N,
315                               SmallVectorImpl<uint64_t> &Record,
316                               unsigned Abbrev);
317   void writeDIEnumerator(const DIEnumerator *N,
318                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
319   void writeDIBasicType(const DIBasicType *N, SmallVectorImpl<uint64_t> &Record,
320                         unsigned Abbrev);
321   void writeDIStringType(const DIStringType *N,
322                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
323   void writeDIDerivedType(const DIDerivedType *N,
324                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
325   void writeDICompositeType(const DICompositeType *N,
326                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
327   void writeDISubroutineType(const DISubroutineType *N,
328                              SmallVectorImpl<uint64_t> &Record,
329                              unsigned Abbrev);
330   void writeDIFile(const DIFile *N, SmallVectorImpl<uint64_t> &Record,
331                    unsigned Abbrev);
332   void writeDICompileUnit(const DICompileUnit *N,
333                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
334   void writeDISubprogram(const DISubprogram *N,
335                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
336   void writeDILexicalBlock(const DILexicalBlock *N,
337                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
338   void writeDILexicalBlockFile(const DILexicalBlockFile *N,
339                                SmallVectorImpl<uint64_t> &Record,
340                                unsigned Abbrev);
341   void writeDICommonBlock(const DICommonBlock *N,
342                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
343   void writeDINamespace(const DINamespace *N, SmallVectorImpl<uint64_t> &Record,
344                         unsigned Abbrev);
345   void writeDIMacro(const DIMacro *N, SmallVectorImpl<uint64_t> &Record,
346                     unsigned Abbrev);
347   void writeDIMacroFile(const DIMacroFile *N, SmallVectorImpl<uint64_t> &Record,
348                         unsigned Abbrev);
349   void writeDIArgList(const DIArgList *N, SmallVectorImpl<uint64_t> &Record);
350   void writeDIModule(const DIModule *N, SmallVectorImpl<uint64_t> &Record,
351                      unsigned Abbrev);
352   void writeDIAssignID(const DIAssignID *N, SmallVectorImpl<uint64_t> &Record,
353                        unsigned Abbrev);
354   void writeDITemplateTypeParameter(const DITemplateTypeParameter *N,
355                                     SmallVectorImpl<uint64_t> &Record,
356                                     unsigned Abbrev);
357   void writeDITemplateValueParameter(const DITemplateValueParameter *N,
358                                      SmallVectorImpl<uint64_t> &Record,
359                                      unsigned Abbrev);
360   void writeDIGlobalVariable(const DIGlobalVariable *N,
361                              SmallVectorImpl<uint64_t> &Record,
362                              unsigned Abbrev);
363   void writeDILocalVariable(const DILocalVariable *N,
364                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
365   void writeDILabel(const DILabel *N,
366                     SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
367   void writeDIExpression(const DIExpression *N,
368                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
369   void writeDIGlobalVariableExpression(const DIGlobalVariableExpression *N,
370                                        SmallVectorImpl<uint64_t> &Record,
371                                        unsigned Abbrev);
372   void writeDIObjCProperty(const DIObjCProperty *N,
373                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
374   void writeDIImportedEntity(const DIImportedEntity *N,
375                              SmallVectorImpl<uint64_t> &Record,
376                              unsigned Abbrev);
377   unsigned createNamedMetadataAbbrev();
378   void writeNamedMetadata(SmallVectorImpl<uint64_t> &Record);
379   unsigned createMetadataStringsAbbrev();
380   void writeMetadataStrings(ArrayRef<const Metadata *> Strings,
381                             SmallVectorImpl<uint64_t> &Record);
382   void writeMetadataRecords(ArrayRef<const Metadata *> MDs,
383                             SmallVectorImpl<uint64_t> &Record,
384                             std::vector<unsigned> *MDAbbrevs = nullptr,
385                             std::vector<uint64_t> *IndexPos = nullptr);
386   void writeModuleMetadata();
387   void writeFunctionMetadata(const Function &F);
388   void writeFunctionMetadataAttachment(const Function &F);
389   void pushGlobalMetadataAttachment(SmallVectorImpl<uint64_t> &Record,
390                                     const GlobalObject &GO);
391   void writeModuleMetadataKinds();
392   void writeOperandBundleTags();
393   void writeSyncScopeNames();
394   void writeConstants(unsigned FirstVal, unsigned LastVal, bool isGlobal);
395   void writeModuleConstants();
396   bool pushValueAndType(const Value *V, unsigned InstID,
397                         SmallVectorImpl<unsigned> &Vals);
398   bool pushValueOrMetadata(const Value *V, unsigned InstID,
399                            SmallVectorImpl<unsigned> &Vals);
400   void writeOperandBundles(const CallBase &CB, unsigned InstID);
401   void pushValue(const Value *V, unsigned InstID,
402                  SmallVectorImpl<unsigned> &Vals);
403   void pushValueSigned(const Value *V, unsigned InstID,
404                        SmallVectorImpl<uint64_t> &Vals);
405   void writeInstruction(const Instruction &I, unsigned InstID,
406                         SmallVectorImpl<unsigned> &Vals);
407   void writeFunctionLevelValueSymbolTable(const ValueSymbolTable &VST);
408   void writeGlobalValueSymbolTable(
409       DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
410   void writeUseList(UseListOrder &&Order);
411   void writeUseListBlock(const Function *F);
412   void
413   writeFunction(const Function &F,
414                 DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
415   void writeBlockInfo();
416   void writeModuleHash(StringRef View);
417 
418   unsigned getEncodedSyncScopeID(SyncScope::ID SSID) {
419     return unsigned(SSID);
420   }
421 
422   unsigned getEncodedAlign(MaybeAlign Alignment) { return encode(Alignment); }
423 };
424 
425 /// Class to manage the bitcode writing for a combined index.
426 class IndexBitcodeWriter : public BitcodeWriterBase {
427   /// The combined index to write to bitcode.
428   const ModuleSummaryIndex &Index;
429 
430   /// When writing combined summaries, provides the set of global value
431   /// summaries for which the value (function, function alias, etc) should be
432   /// imported as a declaration.
433   const GVSummaryPtrSet *DecSummaries = nullptr;
434 
435   /// When writing a subset of the index for distributed backends, client
436   /// provides a map of modules to the corresponding GUIDs/summaries to write.
437   const ModuleToSummariesForIndexTy *ModuleToSummariesForIndex;
438 
439   /// Map that holds the correspondence between the GUID used in the combined
440   /// index and a value id generated by this class to use in references.
441   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
442 
443   // The stack ids used by this index, which will be a subset of those in
444   // the full index in the case of distributed indexes.
445   std::vector<uint64_t> StackIds;
446 
447   // Keep a map of the stack id indices used by records being written for this
448   // index to the index of the corresponding stack id in the above StackIds
449   // vector. Ensures we write each referenced stack id once.
450   DenseMap<unsigned, unsigned> StackIdIndicesToIndex;
451 
452   /// Tracks the last value id recorded in the GUIDToValueMap.
453   unsigned GlobalValueId = 0;
454 
455   /// Tracks the assignment of module paths in the module path string table to
456   /// an id assigned for use in summary references to the module path.
457   DenseMap<StringRef, uint64_t> ModuleIdMap;
458 
459 public:
460   /// Constructs a IndexBitcodeWriter object for the given combined index,
461   /// writing to the provided \p Buffer. When writing a subset of the index
462   /// for a distributed backend, provide a \p ModuleToSummariesForIndex map.
463   /// If provided, \p DecSummaries specifies the set of summaries for which
464   /// the corresponding functions or aliased functions should be imported as a
465   /// declaration (but not definition) for each module.
466   IndexBitcodeWriter(
467       BitstreamWriter &Stream, StringTableBuilder &StrtabBuilder,
468       const ModuleSummaryIndex &Index,
469       const GVSummaryPtrSet *DecSummaries = nullptr,
470       const ModuleToSummariesForIndexTy *ModuleToSummariesForIndex = nullptr)
471       : BitcodeWriterBase(Stream, StrtabBuilder), Index(Index),
472         DecSummaries(DecSummaries),
473         ModuleToSummariesForIndex(ModuleToSummariesForIndex) {
474 
475     // See if the StackIdIndex was already added to the StackId map and
476     // vector. If not, record it.
477     auto RecordStackIdReference = [&](unsigned StackIdIndex) {
478       // If the StackIdIndex is not yet in the map, the below insert ensures
479       // that it will point to the new StackIds vector entry we push to just
480       // below.
481       auto Inserted =
482           StackIdIndicesToIndex.insert({StackIdIndex, StackIds.size()});
483       if (Inserted.second)
484         StackIds.push_back(Index.getStackIdAtIndex(StackIdIndex));
485     };
486 
487     // Assign unique value ids to all summaries to be written, for use
488     // in writing out the call graph edges. Save the mapping from GUID
489     // to the new global value id to use when writing those edges, which
490     // are currently saved in the index in terms of GUID.
491     forEachSummary([&](GVInfo I, bool IsAliasee) {
492       GUIDToValueIdMap[I.first] = ++GlobalValueId;
493       if (IsAliasee)
494         return;
495       auto *FS = dyn_cast<FunctionSummary>(I.second);
496       if (!FS)
497         return;
498       // Record all stack id indices actually used in the summary entries being
499       // written, so that we can compact them in the case of distributed ThinLTO
500       // indexes.
501       for (auto &CI : FS->callsites()) {
502         // If the stack id list is empty, this callsite info was synthesized for
503         // a missing tail call frame. Ensure that the callee's GUID gets a value
504         // id. Normally we only generate these for defined summaries, which in
505         // the case of distributed ThinLTO is only the functions already defined
506         // in the module or that we want to import. We don't bother to include
507         // all the callee symbols as they aren't normally needed in the backend.
508         // However, for the synthesized callsite infos we do need the callee
509         // GUID in the backend so that we can correlate the identified callee
510         // with this callsite info (which for non-tail calls is done by the
511         // ordering of the callsite infos and verified via stack ids).
512         if (CI.StackIdIndices.empty()) {
513           GUIDToValueIdMap[CI.Callee.getGUID()] = ++GlobalValueId;
514           continue;
515         }
516         for (auto Idx : CI.StackIdIndices)
517           RecordStackIdReference(Idx);
518       }
519       for (auto &AI : FS->allocs())
520         for (auto &MIB : AI.MIBs)
521           for (auto Idx : MIB.StackIdIndices)
522             RecordStackIdReference(Idx);
523     });
524   }
525 
526   /// The below iterator returns the GUID and associated summary.
527   using GVInfo = std::pair<GlobalValue::GUID, GlobalValueSummary *>;
528 
529   /// Calls the callback for each value GUID and summary to be written to
530   /// bitcode. This hides the details of whether they are being pulled from the
531   /// entire index or just those in a provided ModuleToSummariesForIndex map.
532   template<typename Functor>
533   void forEachSummary(Functor Callback) {
534     if (ModuleToSummariesForIndex) {
535       for (auto &M : *ModuleToSummariesForIndex)
536         for (auto &Summary : M.second) {
537           Callback(Summary, false);
538           // Ensure aliasee is handled, e.g. for assigning a valueId,
539           // even if we are not importing the aliasee directly (the
540           // imported alias will contain a copy of aliasee).
541           if (auto *AS = dyn_cast<AliasSummary>(Summary.getSecond()))
542             Callback({AS->getAliaseeGUID(), &AS->getAliasee()}, true);
543         }
544     } else {
545       for (auto &Summaries : Index)
546         for (auto &Summary : Summaries.second.SummaryList)
547           Callback({Summaries.first, Summary.get()}, false);
548     }
549   }
550 
551   /// Calls the callback for each entry in the modulePaths StringMap that
552   /// should be written to the module path string table. This hides the details
553   /// of whether they are being pulled from the entire index or just those in a
554   /// provided ModuleToSummariesForIndex map.
555   template <typename Functor> void forEachModule(Functor Callback) {
556     if (ModuleToSummariesForIndex) {
557       for (const auto &M : *ModuleToSummariesForIndex) {
558         const auto &MPI = Index.modulePaths().find(M.first);
559         if (MPI == Index.modulePaths().end()) {
560           // This should only happen if the bitcode file was empty, in which
561           // case we shouldn't be importing (the ModuleToSummariesForIndex
562           // would only include the module we are writing and index for).
563           assert(ModuleToSummariesForIndex->size() == 1);
564           continue;
565         }
566         Callback(*MPI);
567       }
568     } else {
569       // Since StringMap iteration order isn't guaranteed, order by path string
570       // first.
571       // FIXME: Make this a vector of StringMapEntry instead to avoid the later
572       // map lookup.
573       std::vector<StringRef> ModulePaths;
574       for (auto &[ModPath, _] : Index.modulePaths())
575         ModulePaths.push_back(ModPath);
576       llvm::sort(ModulePaths.begin(), ModulePaths.end());
577       for (auto &ModPath : ModulePaths)
578         Callback(*Index.modulePaths().find(ModPath));
579     }
580   }
581 
582   /// Main entry point for writing a combined index to bitcode.
583   void write();
584 
585 private:
586   void writeModStrings();
587   void writeCombinedGlobalValueSummary();
588 
589   std::optional<unsigned> getValueId(GlobalValue::GUID ValGUID) {
590     auto VMI = GUIDToValueIdMap.find(ValGUID);
591     if (VMI == GUIDToValueIdMap.end())
592       return std::nullopt;
593     return VMI->second;
594   }
595 
596   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
597 };
598 
599 } // end anonymous namespace
600 
601 static unsigned getEncodedCastOpcode(unsigned Opcode) {
602   switch (Opcode) {
603   default: llvm_unreachable("Unknown cast instruction!");
604   case Instruction::Trunc   : return bitc::CAST_TRUNC;
605   case Instruction::ZExt    : return bitc::CAST_ZEXT;
606   case Instruction::SExt    : return bitc::CAST_SEXT;
607   case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
608   case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
609   case Instruction::UIToFP  : return bitc::CAST_UITOFP;
610   case Instruction::SIToFP  : return bitc::CAST_SITOFP;
611   case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
612   case Instruction::FPExt   : return bitc::CAST_FPEXT;
613   case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
614   case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
615   case Instruction::BitCast : return bitc::CAST_BITCAST;
616   case Instruction::AddrSpaceCast: return bitc::CAST_ADDRSPACECAST;
617   }
618 }
619 
620 static unsigned getEncodedUnaryOpcode(unsigned Opcode) {
621   switch (Opcode) {
622   default: llvm_unreachable("Unknown binary instruction!");
623   case Instruction::FNeg: return bitc::UNOP_FNEG;
624   }
625 }
626 
627 static unsigned getEncodedBinaryOpcode(unsigned Opcode) {
628   switch (Opcode) {
629   default: llvm_unreachable("Unknown binary instruction!");
630   case Instruction::Add:
631   case Instruction::FAdd: return bitc::BINOP_ADD;
632   case Instruction::Sub:
633   case Instruction::FSub: return bitc::BINOP_SUB;
634   case Instruction::Mul:
635   case Instruction::FMul: return bitc::BINOP_MUL;
636   case Instruction::UDiv: return bitc::BINOP_UDIV;
637   case Instruction::FDiv:
638   case Instruction::SDiv: return bitc::BINOP_SDIV;
639   case Instruction::URem: return bitc::BINOP_UREM;
640   case Instruction::FRem:
641   case Instruction::SRem: return bitc::BINOP_SREM;
642   case Instruction::Shl:  return bitc::BINOP_SHL;
643   case Instruction::LShr: return bitc::BINOP_LSHR;
644   case Instruction::AShr: return bitc::BINOP_ASHR;
645   case Instruction::And:  return bitc::BINOP_AND;
646   case Instruction::Or:   return bitc::BINOP_OR;
647   case Instruction::Xor:  return bitc::BINOP_XOR;
648   }
649 }
650 
651 static unsigned getEncodedRMWOperation(AtomicRMWInst::BinOp Op) {
652   switch (Op) {
653   default: llvm_unreachable("Unknown RMW operation!");
654   case AtomicRMWInst::Xchg: return bitc::RMW_XCHG;
655   case AtomicRMWInst::Add: return bitc::RMW_ADD;
656   case AtomicRMWInst::Sub: return bitc::RMW_SUB;
657   case AtomicRMWInst::And: return bitc::RMW_AND;
658   case AtomicRMWInst::Nand: return bitc::RMW_NAND;
659   case AtomicRMWInst::Or: return bitc::RMW_OR;
660   case AtomicRMWInst::Xor: return bitc::RMW_XOR;
661   case AtomicRMWInst::Max: return bitc::RMW_MAX;
662   case AtomicRMWInst::Min: return bitc::RMW_MIN;
663   case AtomicRMWInst::UMax: return bitc::RMW_UMAX;
664   case AtomicRMWInst::UMin: return bitc::RMW_UMIN;
665   case AtomicRMWInst::FAdd: return bitc::RMW_FADD;
666   case AtomicRMWInst::FSub: return bitc::RMW_FSUB;
667   case AtomicRMWInst::FMax: return bitc::RMW_FMAX;
668   case AtomicRMWInst::FMin: return bitc::RMW_FMIN;
669   case AtomicRMWInst::UIncWrap:
670     return bitc::RMW_UINC_WRAP;
671   case AtomicRMWInst::UDecWrap:
672     return bitc::RMW_UDEC_WRAP;
673   case AtomicRMWInst::USubCond:
674     return bitc::RMW_USUB_COND;
675   case AtomicRMWInst::USubSat:
676     return bitc::RMW_USUB_SAT;
677   }
678 }
679 
680 static unsigned getEncodedOrdering(AtomicOrdering Ordering) {
681   switch (Ordering) {
682   case AtomicOrdering::NotAtomic: return bitc::ORDERING_NOTATOMIC;
683   case AtomicOrdering::Unordered: return bitc::ORDERING_UNORDERED;
684   case AtomicOrdering::Monotonic: return bitc::ORDERING_MONOTONIC;
685   case AtomicOrdering::Acquire: return bitc::ORDERING_ACQUIRE;
686   case AtomicOrdering::Release: return bitc::ORDERING_RELEASE;
687   case AtomicOrdering::AcquireRelease: return bitc::ORDERING_ACQREL;
688   case AtomicOrdering::SequentiallyConsistent: return bitc::ORDERING_SEQCST;
689   }
690   llvm_unreachable("Invalid ordering");
691 }
692 
693 static void writeStringRecord(BitstreamWriter &Stream, unsigned Code,
694                               StringRef Str, unsigned AbbrevToUse) {
695   SmallVector<unsigned, 64> Vals;
696 
697   // Code: [strchar x N]
698   for (char C : Str) {
699     if (AbbrevToUse && !BitCodeAbbrevOp::isChar6(C))
700       AbbrevToUse = 0;
701     Vals.push_back(C);
702   }
703 
704   // Emit the finished record.
705   Stream.EmitRecord(Code, Vals, AbbrevToUse);
706 }
707 
708 static uint64_t getAttrKindEncoding(Attribute::AttrKind Kind) {
709   switch (Kind) {
710   case Attribute::Alignment:
711     return bitc::ATTR_KIND_ALIGNMENT;
712   case Attribute::AllocAlign:
713     return bitc::ATTR_KIND_ALLOC_ALIGN;
714   case Attribute::AllocSize:
715     return bitc::ATTR_KIND_ALLOC_SIZE;
716   case Attribute::AlwaysInline:
717     return bitc::ATTR_KIND_ALWAYS_INLINE;
718   case Attribute::Builtin:
719     return bitc::ATTR_KIND_BUILTIN;
720   case Attribute::ByVal:
721     return bitc::ATTR_KIND_BY_VAL;
722   case Attribute::Convergent:
723     return bitc::ATTR_KIND_CONVERGENT;
724   case Attribute::InAlloca:
725     return bitc::ATTR_KIND_IN_ALLOCA;
726   case Attribute::Cold:
727     return bitc::ATTR_KIND_COLD;
728   case Attribute::DisableSanitizerInstrumentation:
729     return bitc::ATTR_KIND_DISABLE_SANITIZER_INSTRUMENTATION;
730   case Attribute::FnRetThunkExtern:
731     return bitc::ATTR_KIND_FNRETTHUNK_EXTERN;
732   case Attribute::Hot:
733     return bitc::ATTR_KIND_HOT;
734   case Attribute::ElementType:
735     return bitc::ATTR_KIND_ELEMENTTYPE;
736   case Attribute::HybridPatchable:
737     return bitc::ATTR_KIND_HYBRID_PATCHABLE;
738   case Attribute::InlineHint:
739     return bitc::ATTR_KIND_INLINE_HINT;
740   case Attribute::InReg:
741     return bitc::ATTR_KIND_IN_REG;
742   case Attribute::JumpTable:
743     return bitc::ATTR_KIND_JUMP_TABLE;
744   case Attribute::MinSize:
745     return bitc::ATTR_KIND_MIN_SIZE;
746   case Attribute::AllocatedPointer:
747     return bitc::ATTR_KIND_ALLOCATED_POINTER;
748   case Attribute::AllocKind:
749     return bitc::ATTR_KIND_ALLOC_KIND;
750   case Attribute::Memory:
751     return bitc::ATTR_KIND_MEMORY;
752   case Attribute::NoFPClass:
753     return bitc::ATTR_KIND_NOFPCLASS;
754   case Attribute::Naked:
755     return bitc::ATTR_KIND_NAKED;
756   case Attribute::Nest:
757     return bitc::ATTR_KIND_NEST;
758   case Attribute::NoAlias:
759     return bitc::ATTR_KIND_NO_ALIAS;
760   case Attribute::NoBuiltin:
761     return bitc::ATTR_KIND_NO_BUILTIN;
762   case Attribute::NoCallback:
763     return bitc::ATTR_KIND_NO_CALLBACK;
764   case Attribute::NoCapture:
765     return bitc::ATTR_KIND_NO_CAPTURE;
766   case Attribute::NoDivergenceSource:
767     return bitc::ATTR_KIND_NO_DIVERGENCE_SOURCE;
768   case Attribute::NoDuplicate:
769     return bitc::ATTR_KIND_NO_DUPLICATE;
770   case Attribute::NoFree:
771     return bitc::ATTR_KIND_NOFREE;
772   case Attribute::NoImplicitFloat:
773     return bitc::ATTR_KIND_NO_IMPLICIT_FLOAT;
774   case Attribute::NoInline:
775     return bitc::ATTR_KIND_NO_INLINE;
776   case Attribute::NoRecurse:
777     return bitc::ATTR_KIND_NO_RECURSE;
778   case Attribute::NoMerge:
779     return bitc::ATTR_KIND_NO_MERGE;
780   case Attribute::NonLazyBind:
781     return bitc::ATTR_KIND_NON_LAZY_BIND;
782   case Attribute::NonNull:
783     return bitc::ATTR_KIND_NON_NULL;
784   case Attribute::Dereferenceable:
785     return bitc::ATTR_KIND_DEREFERENCEABLE;
786   case Attribute::DereferenceableOrNull:
787     return bitc::ATTR_KIND_DEREFERENCEABLE_OR_NULL;
788   case Attribute::NoRedZone:
789     return bitc::ATTR_KIND_NO_RED_ZONE;
790   case Attribute::NoReturn:
791     return bitc::ATTR_KIND_NO_RETURN;
792   case Attribute::NoSync:
793     return bitc::ATTR_KIND_NOSYNC;
794   case Attribute::NoCfCheck:
795     return bitc::ATTR_KIND_NOCF_CHECK;
796   case Attribute::NoProfile:
797     return bitc::ATTR_KIND_NO_PROFILE;
798   case Attribute::SkipProfile:
799     return bitc::ATTR_KIND_SKIP_PROFILE;
800   case Attribute::NoUnwind:
801     return bitc::ATTR_KIND_NO_UNWIND;
802   case Attribute::NoSanitizeBounds:
803     return bitc::ATTR_KIND_NO_SANITIZE_BOUNDS;
804   case Attribute::NoSanitizeCoverage:
805     return bitc::ATTR_KIND_NO_SANITIZE_COVERAGE;
806   case Attribute::NullPointerIsValid:
807     return bitc::ATTR_KIND_NULL_POINTER_IS_VALID;
808   case Attribute::OptimizeForDebugging:
809     return bitc::ATTR_KIND_OPTIMIZE_FOR_DEBUGGING;
810   case Attribute::OptForFuzzing:
811     return bitc::ATTR_KIND_OPT_FOR_FUZZING;
812   case Attribute::OptimizeForSize:
813     return bitc::ATTR_KIND_OPTIMIZE_FOR_SIZE;
814   case Attribute::OptimizeNone:
815     return bitc::ATTR_KIND_OPTIMIZE_NONE;
816   case Attribute::ReadNone:
817     return bitc::ATTR_KIND_READ_NONE;
818   case Attribute::ReadOnly:
819     return bitc::ATTR_KIND_READ_ONLY;
820   case Attribute::Returned:
821     return bitc::ATTR_KIND_RETURNED;
822   case Attribute::ReturnsTwice:
823     return bitc::ATTR_KIND_RETURNS_TWICE;
824   case Attribute::SExt:
825     return bitc::ATTR_KIND_S_EXT;
826   case Attribute::Speculatable:
827     return bitc::ATTR_KIND_SPECULATABLE;
828   case Attribute::StackAlignment:
829     return bitc::ATTR_KIND_STACK_ALIGNMENT;
830   case Attribute::StackProtect:
831     return bitc::ATTR_KIND_STACK_PROTECT;
832   case Attribute::StackProtectReq:
833     return bitc::ATTR_KIND_STACK_PROTECT_REQ;
834   case Attribute::StackProtectStrong:
835     return bitc::ATTR_KIND_STACK_PROTECT_STRONG;
836   case Attribute::SafeStack:
837     return bitc::ATTR_KIND_SAFESTACK;
838   case Attribute::ShadowCallStack:
839     return bitc::ATTR_KIND_SHADOWCALLSTACK;
840   case Attribute::StrictFP:
841     return bitc::ATTR_KIND_STRICT_FP;
842   case Attribute::StructRet:
843     return bitc::ATTR_KIND_STRUCT_RET;
844   case Attribute::SanitizeAddress:
845     return bitc::ATTR_KIND_SANITIZE_ADDRESS;
846   case Attribute::SanitizeHWAddress:
847     return bitc::ATTR_KIND_SANITIZE_HWADDRESS;
848   case Attribute::SanitizeThread:
849     return bitc::ATTR_KIND_SANITIZE_THREAD;
850   case Attribute::SanitizeMemory:
851     return bitc::ATTR_KIND_SANITIZE_MEMORY;
852   case Attribute::SanitizeNumericalStability:
853     return bitc::ATTR_KIND_SANITIZE_NUMERICAL_STABILITY;
854   case Attribute::SanitizeRealtime:
855     return bitc::ATTR_KIND_SANITIZE_REALTIME;
856   case Attribute::SanitizeRealtimeBlocking:
857     return bitc::ATTR_KIND_SANITIZE_REALTIME_BLOCKING;
858   case Attribute::SpeculativeLoadHardening:
859     return bitc::ATTR_KIND_SPECULATIVE_LOAD_HARDENING;
860   case Attribute::SwiftError:
861     return bitc::ATTR_KIND_SWIFT_ERROR;
862   case Attribute::SwiftSelf:
863     return bitc::ATTR_KIND_SWIFT_SELF;
864   case Attribute::SwiftAsync:
865     return bitc::ATTR_KIND_SWIFT_ASYNC;
866   case Attribute::UWTable:
867     return bitc::ATTR_KIND_UW_TABLE;
868   case Attribute::VScaleRange:
869     return bitc::ATTR_KIND_VSCALE_RANGE;
870   case Attribute::WillReturn:
871     return bitc::ATTR_KIND_WILLRETURN;
872   case Attribute::WriteOnly:
873     return bitc::ATTR_KIND_WRITEONLY;
874   case Attribute::ZExt:
875     return bitc::ATTR_KIND_Z_EXT;
876   case Attribute::ImmArg:
877     return bitc::ATTR_KIND_IMMARG;
878   case Attribute::SanitizeMemTag:
879     return bitc::ATTR_KIND_SANITIZE_MEMTAG;
880   case Attribute::Preallocated:
881     return bitc::ATTR_KIND_PREALLOCATED;
882   case Attribute::NoUndef:
883     return bitc::ATTR_KIND_NOUNDEF;
884   case Attribute::ByRef:
885     return bitc::ATTR_KIND_BYREF;
886   case Attribute::MustProgress:
887     return bitc::ATTR_KIND_MUSTPROGRESS;
888   case Attribute::PresplitCoroutine:
889     return bitc::ATTR_KIND_PRESPLIT_COROUTINE;
890   case Attribute::Writable:
891     return bitc::ATTR_KIND_WRITABLE;
892   case Attribute::CoroDestroyOnlyWhenComplete:
893     return bitc::ATTR_KIND_CORO_ONLY_DESTROY_WHEN_COMPLETE;
894   case Attribute::CoroElideSafe:
895     return bitc::ATTR_KIND_CORO_ELIDE_SAFE;
896   case Attribute::DeadOnUnwind:
897     return bitc::ATTR_KIND_DEAD_ON_UNWIND;
898   case Attribute::Range:
899     return bitc::ATTR_KIND_RANGE;
900   case Attribute::Initializes:
901     return bitc::ATTR_KIND_INITIALIZES;
902   case Attribute::NoExt:
903     return bitc::ATTR_KIND_NO_EXT;
904   case Attribute::EndAttrKinds:
905     llvm_unreachable("Can not encode end-attribute kinds marker.");
906   case Attribute::None:
907     llvm_unreachable("Can not encode none-attribute.");
908   case Attribute::EmptyKey:
909   case Attribute::TombstoneKey:
910     llvm_unreachable("Trying to encode EmptyKey/TombstoneKey");
911   }
912 
913   llvm_unreachable("Trying to encode unknown attribute");
914 }
915 
916 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
917   if ((int64_t)V >= 0)
918     Vals.push_back(V << 1);
919   else
920     Vals.push_back((-V << 1) | 1);
921 }
922 
923 static void emitWideAPInt(SmallVectorImpl<uint64_t> &Vals, const APInt &A) {
924   // We have an arbitrary precision integer value to write whose
925   // bit width is > 64. However, in canonical unsigned integer
926   // format it is likely that the high bits are going to be zero.
927   // So, we only write the number of active words.
928   unsigned NumWords = A.getActiveWords();
929   const uint64_t *RawData = A.getRawData();
930   for (unsigned i = 0; i < NumWords; i++)
931     emitSignedInt64(Vals, RawData[i]);
932 }
933 
934 static void emitConstantRange(SmallVectorImpl<uint64_t> &Record,
935                               const ConstantRange &CR, bool EmitBitWidth) {
936   unsigned BitWidth = CR.getBitWidth();
937   if (EmitBitWidth)
938     Record.push_back(BitWidth);
939   if (BitWidth > 64) {
940     Record.push_back(CR.getLower().getActiveWords() |
941                      (uint64_t(CR.getUpper().getActiveWords()) << 32));
942     emitWideAPInt(Record, CR.getLower());
943     emitWideAPInt(Record, CR.getUpper());
944   } else {
945     emitSignedInt64(Record, CR.getLower().getSExtValue());
946     emitSignedInt64(Record, CR.getUpper().getSExtValue());
947   }
948 }
949 
950 void ModuleBitcodeWriter::writeAttributeGroupTable() {
951   const std::vector<ValueEnumerator::IndexAndAttrSet> &AttrGrps =
952       VE.getAttributeGroups();
953   if (AttrGrps.empty()) return;
954 
955   Stream.EnterSubblock(bitc::PARAMATTR_GROUP_BLOCK_ID, 3);
956 
957   SmallVector<uint64_t, 64> Record;
958   for (ValueEnumerator::IndexAndAttrSet Pair : AttrGrps) {
959     unsigned AttrListIndex = Pair.first;
960     AttributeSet AS = Pair.second;
961     Record.push_back(VE.getAttributeGroupID(Pair));
962     Record.push_back(AttrListIndex);
963 
964     for (Attribute Attr : AS) {
965       if (Attr.isEnumAttribute()) {
966         Record.push_back(0);
967         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
968       } else if (Attr.isIntAttribute()) {
969         Record.push_back(1);
970         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
971         Record.push_back(Attr.getValueAsInt());
972       } else if (Attr.isStringAttribute()) {
973         StringRef Kind = Attr.getKindAsString();
974         StringRef Val = Attr.getValueAsString();
975 
976         Record.push_back(Val.empty() ? 3 : 4);
977         Record.append(Kind.begin(), Kind.end());
978         Record.push_back(0);
979         if (!Val.empty()) {
980           Record.append(Val.begin(), Val.end());
981           Record.push_back(0);
982         }
983       } else if (Attr.isTypeAttribute()) {
984         Type *Ty = Attr.getValueAsType();
985         Record.push_back(Ty ? 6 : 5);
986         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
987         if (Ty)
988           Record.push_back(VE.getTypeID(Attr.getValueAsType()));
989       } else if (Attr.isConstantRangeAttribute()) {
990         Record.push_back(7);
991         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
992         emitConstantRange(Record, Attr.getValueAsConstantRange(),
993                           /*EmitBitWidth=*/true);
994       } else {
995         assert(Attr.isConstantRangeListAttribute());
996         Record.push_back(8);
997         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
998         ArrayRef<ConstantRange> Val = Attr.getValueAsConstantRangeList();
999         Record.push_back(Val.size());
1000         Record.push_back(Val[0].getBitWidth());
1001         for (auto &CR : Val)
1002           emitConstantRange(Record, CR, /*EmitBitWidth=*/false);
1003       }
1004     }
1005 
1006     Stream.EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
1007     Record.clear();
1008   }
1009 
1010   Stream.ExitBlock();
1011 }
1012 
1013 void ModuleBitcodeWriter::writeAttributeTable() {
1014   const std::vector<AttributeList> &Attrs = VE.getAttributeLists();
1015   if (Attrs.empty()) return;
1016 
1017   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
1018 
1019   SmallVector<uint64_t, 64> Record;
1020   for (const AttributeList &AL : Attrs) {
1021     for (unsigned i : AL.indexes()) {
1022       AttributeSet AS = AL.getAttributes(i);
1023       if (AS.hasAttributes())
1024         Record.push_back(VE.getAttributeGroupID({i, AS}));
1025     }
1026 
1027     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
1028     Record.clear();
1029   }
1030 
1031   Stream.ExitBlock();
1032 }
1033 
1034 /// WriteTypeTable - Write out the type table for a module.
1035 void ModuleBitcodeWriter::writeTypeTable() {
1036   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
1037 
1038   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
1039   SmallVector<uint64_t, 64> TypeVals;
1040 
1041   uint64_t NumBits = VE.computeBitsRequiredForTypeIndices();
1042 
1043   // Abbrev for TYPE_CODE_OPAQUE_POINTER.
1044   auto Abbv = std::make_shared<BitCodeAbbrev>();
1045   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_OPAQUE_POINTER));
1046   Abbv->Add(BitCodeAbbrevOp(0)); // Addrspace = 0
1047   unsigned OpaquePtrAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1048 
1049   // Abbrev for TYPE_CODE_FUNCTION.
1050   Abbv = std::make_shared<BitCodeAbbrev>();
1051   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
1052   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
1053   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1054   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
1055   unsigned FunctionAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1056 
1057   // Abbrev for TYPE_CODE_STRUCT_ANON.
1058   Abbv = std::make_shared<BitCodeAbbrev>();
1059   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
1060   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
1061   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1062   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
1063   unsigned StructAnonAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1064 
1065   // Abbrev for TYPE_CODE_STRUCT_NAME.
1066   Abbv = std::make_shared<BitCodeAbbrev>();
1067   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
1068   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1069   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1070   unsigned StructNameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1071 
1072   // Abbrev for TYPE_CODE_STRUCT_NAMED.
1073   Abbv = std::make_shared<BitCodeAbbrev>();
1074   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
1075   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
1076   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1077   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
1078   unsigned StructNamedAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1079 
1080   // Abbrev for TYPE_CODE_ARRAY.
1081   Abbv = std::make_shared<BitCodeAbbrev>();
1082   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
1083   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
1084   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
1085   unsigned ArrayAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1086 
1087   // Emit an entry count so the reader can reserve space.
1088   TypeVals.push_back(TypeList.size());
1089   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
1090   TypeVals.clear();
1091 
1092   // Loop over all of the types, emitting each in turn.
1093   for (Type *T : TypeList) {
1094     int AbbrevToUse = 0;
1095     unsigned Code = 0;
1096 
1097     switch (T->getTypeID()) {
1098     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;      break;
1099     case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;      break;
1100     case Type::BFloatTyID:    Code = bitc::TYPE_CODE_BFLOAT;    break;
1101     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;     break;
1102     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE;    break;
1103     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80;  break;
1104     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128;     break;
1105     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
1106     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;     break;
1107     case Type::MetadataTyID:
1108       Code = bitc::TYPE_CODE_METADATA;
1109       break;
1110     case Type::X86_AMXTyID:   Code = bitc::TYPE_CODE_X86_AMX;   break;
1111     case Type::TokenTyID:     Code = bitc::TYPE_CODE_TOKEN;     break;
1112     case Type::IntegerTyID:
1113       // INTEGER: [width]
1114       Code = bitc::TYPE_CODE_INTEGER;
1115       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
1116       break;
1117     case Type::PointerTyID: {
1118       PointerType *PTy = cast<PointerType>(T);
1119       unsigned AddressSpace = PTy->getAddressSpace();
1120       // OPAQUE_POINTER: [address space]
1121       Code = bitc::TYPE_CODE_OPAQUE_POINTER;
1122       TypeVals.push_back(AddressSpace);
1123       if (AddressSpace == 0)
1124         AbbrevToUse = OpaquePtrAbbrev;
1125       break;
1126     }
1127     case Type::FunctionTyID: {
1128       FunctionType *FT = cast<FunctionType>(T);
1129       // FUNCTION: [isvararg, retty, paramty x N]
1130       Code = bitc::TYPE_CODE_FUNCTION;
1131       TypeVals.push_back(FT->isVarArg());
1132       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
1133       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
1134         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
1135       AbbrevToUse = FunctionAbbrev;
1136       break;
1137     }
1138     case Type::StructTyID: {
1139       StructType *ST = cast<StructType>(T);
1140       // STRUCT: [ispacked, eltty x N]
1141       TypeVals.push_back(ST->isPacked());
1142       // Output all of the element types.
1143       for (Type *ET : ST->elements())
1144         TypeVals.push_back(VE.getTypeID(ET));
1145 
1146       if (ST->isLiteral()) {
1147         Code = bitc::TYPE_CODE_STRUCT_ANON;
1148         AbbrevToUse = StructAnonAbbrev;
1149       } else {
1150         if (ST->isOpaque()) {
1151           Code = bitc::TYPE_CODE_OPAQUE;
1152         } else {
1153           Code = bitc::TYPE_CODE_STRUCT_NAMED;
1154           AbbrevToUse = StructNamedAbbrev;
1155         }
1156 
1157         // Emit the name if it is present.
1158         if (!ST->getName().empty())
1159           writeStringRecord(Stream, bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
1160                             StructNameAbbrev);
1161       }
1162       break;
1163     }
1164     case Type::ArrayTyID: {
1165       ArrayType *AT = cast<ArrayType>(T);
1166       // ARRAY: [numelts, eltty]
1167       Code = bitc::TYPE_CODE_ARRAY;
1168       TypeVals.push_back(AT->getNumElements());
1169       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
1170       AbbrevToUse = ArrayAbbrev;
1171       break;
1172     }
1173     case Type::FixedVectorTyID:
1174     case Type::ScalableVectorTyID: {
1175       VectorType *VT = cast<VectorType>(T);
1176       // VECTOR [numelts, eltty] or
1177       //        [numelts, eltty, scalable]
1178       Code = bitc::TYPE_CODE_VECTOR;
1179       TypeVals.push_back(VT->getElementCount().getKnownMinValue());
1180       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
1181       if (isa<ScalableVectorType>(VT))
1182         TypeVals.push_back(true);
1183       break;
1184     }
1185     case Type::TargetExtTyID: {
1186       TargetExtType *TET = cast<TargetExtType>(T);
1187       Code = bitc::TYPE_CODE_TARGET_TYPE;
1188       writeStringRecord(Stream, bitc::TYPE_CODE_STRUCT_NAME, TET->getName(),
1189                         StructNameAbbrev);
1190       TypeVals.push_back(TET->getNumTypeParameters());
1191       for (Type *InnerTy : TET->type_params())
1192         TypeVals.push_back(VE.getTypeID(InnerTy));
1193       for (unsigned IntParam : TET->int_params())
1194         TypeVals.push_back(IntParam);
1195       break;
1196     }
1197     case Type::TypedPointerTyID:
1198       llvm_unreachable("Typed pointers cannot be added to IR modules");
1199     }
1200 
1201     // Emit the finished record.
1202     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
1203     TypeVals.clear();
1204   }
1205 
1206   Stream.ExitBlock();
1207 }
1208 
1209 static unsigned getEncodedLinkage(const GlobalValue::LinkageTypes Linkage) {
1210   switch (Linkage) {
1211   case GlobalValue::ExternalLinkage:
1212     return 0;
1213   case GlobalValue::WeakAnyLinkage:
1214     return 16;
1215   case GlobalValue::AppendingLinkage:
1216     return 2;
1217   case GlobalValue::InternalLinkage:
1218     return 3;
1219   case GlobalValue::LinkOnceAnyLinkage:
1220     return 18;
1221   case GlobalValue::ExternalWeakLinkage:
1222     return 7;
1223   case GlobalValue::CommonLinkage:
1224     return 8;
1225   case GlobalValue::PrivateLinkage:
1226     return 9;
1227   case GlobalValue::WeakODRLinkage:
1228     return 17;
1229   case GlobalValue::LinkOnceODRLinkage:
1230     return 19;
1231   case GlobalValue::AvailableExternallyLinkage:
1232     return 12;
1233   }
1234   llvm_unreachable("Invalid linkage");
1235 }
1236 
1237 static unsigned getEncodedLinkage(const GlobalValue &GV) {
1238   return getEncodedLinkage(GV.getLinkage());
1239 }
1240 
1241 static uint64_t getEncodedFFlags(FunctionSummary::FFlags Flags) {
1242   uint64_t RawFlags = 0;
1243   RawFlags |= Flags.ReadNone;
1244   RawFlags |= (Flags.ReadOnly << 1);
1245   RawFlags |= (Flags.NoRecurse << 2);
1246   RawFlags |= (Flags.ReturnDoesNotAlias << 3);
1247   RawFlags |= (Flags.NoInline << 4);
1248   RawFlags |= (Flags.AlwaysInline << 5);
1249   RawFlags |= (Flags.NoUnwind << 6);
1250   RawFlags |= (Flags.MayThrow << 7);
1251   RawFlags |= (Flags.HasUnknownCall << 8);
1252   RawFlags |= (Flags.MustBeUnreachable << 9);
1253   return RawFlags;
1254 }
1255 
1256 // Decode the flags for GlobalValue in the summary. See getDecodedGVSummaryFlags
1257 // in BitcodeReader.cpp.
1258 static uint64_t getEncodedGVSummaryFlags(GlobalValueSummary::GVFlags Flags,
1259                                          bool ImportAsDecl = false) {
1260   uint64_t RawFlags = 0;
1261 
1262   RawFlags |= Flags.NotEligibleToImport; // bool
1263   RawFlags |= (Flags.Live << 1);
1264   RawFlags |= (Flags.DSOLocal << 2);
1265   RawFlags |= (Flags.CanAutoHide << 3);
1266 
1267   // Linkage don't need to be remapped at that time for the summary. Any future
1268   // change to the getEncodedLinkage() function will need to be taken into
1269   // account here as well.
1270   RawFlags = (RawFlags << 4) | Flags.Linkage; // 4 bits
1271 
1272   RawFlags |= (Flags.Visibility << 8); // 2 bits
1273 
1274   unsigned ImportType = Flags.ImportType | ImportAsDecl;
1275   RawFlags |= (ImportType << 10); // 1 bit
1276 
1277   return RawFlags;
1278 }
1279 
1280 static uint64_t getEncodedGVarFlags(GlobalVarSummary::GVarFlags Flags) {
1281   uint64_t RawFlags = Flags.MaybeReadOnly | (Flags.MaybeWriteOnly << 1) |
1282                       (Flags.Constant << 2) | Flags.VCallVisibility << 3;
1283   return RawFlags;
1284 }
1285 
1286 static uint64_t getEncodedHotnessCallEdgeInfo(const CalleeInfo &CI) {
1287   uint64_t RawFlags = 0;
1288 
1289   RawFlags |= CI.Hotness;            // 3 bits
1290   RawFlags |= (CI.HasTailCall << 3); // 1 bit
1291 
1292   return RawFlags;
1293 }
1294 
1295 static uint64_t getEncodedRelBFCallEdgeInfo(const CalleeInfo &CI) {
1296   uint64_t RawFlags = 0;
1297 
1298   RawFlags |= CI.RelBlockFreq; // CalleeInfo::RelBlockFreqBits bits
1299   RawFlags |= (CI.HasTailCall << CalleeInfo::RelBlockFreqBits); // 1 bit
1300 
1301   return RawFlags;
1302 }
1303 
1304 static unsigned getEncodedVisibility(const GlobalValue &GV) {
1305   switch (GV.getVisibility()) {
1306   case GlobalValue::DefaultVisibility:   return 0;
1307   case GlobalValue::HiddenVisibility:    return 1;
1308   case GlobalValue::ProtectedVisibility: return 2;
1309   }
1310   llvm_unreachable("Invalid visibility");
1311 }
1312 
1313 static unsigned getEncodedDLLStorageClass(const GlobalValue &GV) {
1314   switch (GV.getDLLStorageClass()) {
1315   case GlobalValue::DefaultStorageClass:   return 0;
1316   case GlobalValue::DLLImportStorageClass: return 1;
1317   case GlobalValue::DLLExportStorageClass: return 2;
1318   }
1319   llvm_unreachable("Invalid DLL storage class");
1320 }
1321 
1322 static unsigned getEncodedThreadLocalMode(const GlobalValue &GV) {
1323   switch (GV.getThreadLocalMode()) {
1324     case GlobalVariable::NotThreadLocal:         return 0;
1325     case GlobalVariable::GeneralDynamicTLSModel: return 1;
1326     case GlobalVariable::LocalDynamicTLSModel:   return 2;
1327     case GlobalVariable::InitialExecTLSModel:    return 3;
1328     case GlobalVariable::LocalExecTLSModel:      return 4;
1329   }
1330   llvm_unreachable("Invalid TLS model");
1331 }
1332 
1333 static unsigned getEncodedComdatSelectionKind(const Comdat &C) {
1334   switch (C.getSelectionKind()) {
1335   case Comdat::Any:
1336     return bitc::COMDAT_SELECTION_KIND_ANY;
1337   case Comdat::ExactMatch:
1338     return bitc::COMDAT_SELECTION_KIND_EXACT_MATCH;
1339   case Comdat::Largest:
1340     return bitc::COMDAT_SELECTION_KIND_LARGEST;
1341   case Comdat::NoDeduplicate:
1342     return bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES;
1343   case Comdat::SameSize:
1344     return bitc::COMDAT_SELECTION_KIND_SAME_SIZE;
1345   }
1346   llvm_unreachable("Invalid selection kind");
1347 }
1348 
1349 static unsigned getEncodedUnnamedAddr(const GlobalValue &GV) {
1350   switch (GV.getUnnamedAddr()) {
1351   case GlobalValue::UnnamedAddr::None:   return 0;
1352   case GlobalValue::UnnamedAddr::Local:  return 2;
1353   case GlobalValue::UnnamedAddr::Global: return 1;
1354   }
1355   llvm_unreachable("Invalid unnamed_addr");
1356 }
1357 
1358 size_t ModuleBitcodeWriter::addToStrtab(StringRef Str) {
1359   if (GenerateHash)
1360     Hasher.update(Str);
1361   return StrtabBuilder.add(Str);
1362 }
1363 
1364 void ModuleBitcodeWriter::writeComdats() {
1365   SmallVector<unsigned, 64> Vals;
1366   for (const Comdat *C : VE.getComdats()) {
1367     // COMDAT: [strtab offset, strtab size, selection_kind]
1368     Vals.push_back(addToStrtab(C->getName()));
1369     Vals.push_back(C->getName().size());
1370     Vals.push_back(getEncodedComdatSelectionKind(*C));
1371     Stream.EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
1372     Vals.clear();
1373   }
1374 }
1375 
1376 /// Write a record that will eventually hold the word offset of the
1377 /// module-level VST. For now the offset is 0, which will be backpatched
1378 /// after the real VST is written. Saves the bit offset to backpatch.
1379 void ModuleBitcodeWriter::writeValueSymbolTableForwardDecl() {
1380   // Write a placeholder value in for the offset of the real VST,
1381   // which is written after the function blocks so that it can include
1382   // the offset of each function. The placeholder offset will be
1383   // updated when the real VST is written.
1384   auto Abbv = std::make_shared<BitCodeAbbrev>();
1385   Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_VSTOFFSET));
1386   // Blocks are 32-bit aligned, so we can use a 32-bit word offset to
1387   // hold the real VST offset. Must use fixed instead of VBR as we don't
1388   // know how many VBR chunks to reserve ahead of time.
1389   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
1390   unsigned VSTOffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1391 
1392   // Emit the placeholder
1393   uint64_t Vals[] = {bitc::MODULE_CODE_VSTOFFSET, 0};
1394   Stream.EmitRecordWithAbbrev(VSTOffsetAbbrev, Vals);
1395 
1396   // Compute and save the bit offset to the placeholder, which will be
1397   // patched when the real VST is written. We can simply subtract the 32-bit
1398   // fixed size from the current bit number to get the location to backpatch.
1399   VSTOffsetPlaceholder = Stream.GetCurrentBitNo() - 32;
1400 }
1401 
1402 enum StringEncoding { SE_Char6, SE_Fixed7, SE_Fixed8 };
1403 
1404 /// Determine the encoding to use for the given string name and length.
1405 static StringEncoding getStringEncoding(StringRef Str) {
1406   bool isChar6 = true;
1407   for (char C : Str) {
1408     if (isChar6)
1409       isChar6 = BitCodeAbbrevOp::isChar6(C);
1410     if ((unsigned char)C & 128)
1411       // don't bother scanning the rest.
1412       return SE_Fixed8;
1413   }
1414   if (isChar6)
1415     return SE_Char6;
1416   return SE_Fixed7;
1417 }
1418 
1419 static_assert(sizeof(GlobalValue::SanitizerMetadata) <= sizeof(unsigned),
1420               "Sanitizer Metadata is too large for naive serialization.");
1421 static unsigned
1422 serializeSanitizerMetadata(const GlobalValue::SanitizerMetadata &Meta) {
1423   return Meta.NoAddress | (Meta.NoHWAddress << 1) |
1424          (Meta.Memtag << 2) | (Meta.IsDynInit << 3);
1425 }
1426 
1427 /// Emit top-level description of module, including target triple, inline asm,
1428 /// descriptors for global variables, and function prototype info.
1429 /// Returns the bit offset to backpatch with the location of the real VST.
1430 void ModuleBitcodeWriter::writeModuleInfo() {
1431   // Emit various pieces of data attached to a module.
1432   if (!M.getTargetTriple().empty())
1433     writeStringRecord(Stream, bitc::MODULE_CODE_TRIPLE, M.getTargetTriple(),
1434                       0 /*TODO*/);
1435   const std::string &DL = M.getDataLayoutStr();
1436   if (!DL.empty())
1437     writeStringRecord(Stream, bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/);
1438   if (!M.getModuleInlineAsm().empty())
1439     writeStringRecord(Stream, bitc::MODULE_CODE_ASM, M.getModuleInlineAsm(),
1440                       0 /*TODO*/);
1441 
1442   // Emit information about sections and GC, computing how many there are. Also
1443   // compute the maximum alignment value.
1444   std::map<std::string, unsigned> SectionMap;
1445   std::map<std::string, unsigned> GCMap;
1446   MaybeAlign MaxAlignment;
1447   unsigned MaxGlobalType = 0;
1448   const auto UpdateMaxAlignment = [&MaxAlignment](const MaybeAlign A) {
1449     if (A)
1450       MaxAlignment = !MaxAlignment ? *A : std::max(*MaxAlignment, *A);
1451   };
1452   for (const GlobalVariable &GV : M.globals()) {
1453     UpdateMaxAlignment(GV.getAlign());
1454     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getValueType()));
1455     if (GV.hasSection()) {
1456       // Give section names unique ID's.
1457       unsigned &Entry = SectionMap[std::string(GV.getSection())];
1458       if (!Entry) {
1459         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
1460                           0 /*TODO*/);
1461         Entry = SectionMap.size();
1462       }
1463     }
1464   }
1465   for (const Function &F : M) {
1466     UpdateMaxAlignment(F.getAlign());
1467     if (F.hasSection()) {
1468       // Give section names unique ID's.
1469       unsigned &Entry = SectionMap[std::string(F.getSection())];
1470       if (!Entry) {
1471         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
1472                           0 /*TODO*/);
1473         Entry = SectionMap.size();
1474       }
1475     }
1476     if (F.hasGC()) {
1477       // Same for GC names.
1478       unsigned &Entry = GCMap[F.getGC()];
1479       if (!Entry) {
1480         writeStringRecord(Stream, bitc::MODULE_CODE_GCNAME, F.getGC(),
1481                           0 /*TODO*/);
1482         Entry = GCMap.size();
1483       }
1484     }
1485   }
1486 
1487   // Emit abbrev for globals, now that we know # sections and max alignment.
1488   unsigned SimpleGVarAbbrev = 0;
1489   if (!M.global_empty()) {
1490     // Add an abbrev for common globals with no visibility or thread localness.
1491     auto Abbv = std::make_shared<BitCodeAbbrev>();
1492     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
1493     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1494     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1495     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1496                               Log2_32_Ceil(MaxGlobalType+1)));
1497     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddrSpace << 2
1498                                                            //| explicitType << 1
1499                                                            //| constant
1500     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Initializer.
1501     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // Linkage.
1502     if (!MaxAlignment)                                     // Alignment.
1503       Abbv->Add(BitCodeAbbrevOp(0));
1504     else {
1505       unsigned MaxEncAlignment = getEncodedAlign(MaxAlignment);
1506       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1507                                Log2_32_Ceil(MaxEncAlignment+1)));
1508     }
1509     if (SectionMap.empty())                                    // Section.
1510       Abbv->Add(BitCodeAbbrevOp(0));
1511     else
1512       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1513                                Log2_32_Ceil(SectionMap.size()+1)));
1514     // Don't bother emitting vis + thread local.
1515     SimpleGVarAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1516   }
1517 
1518   SmallVector<unsigned, 64> Vals;
1519   // Emit the module's source file name.
1520   {
1521     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
1522     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
1523     if (Bits == SE_Char6)
1524       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
1525     else if (Bits == SE_Fixed7)
1526       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
1527 
1528     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
1529     auto Abbv = std::make_shared<BitCodeAbbrev>();
1530     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
1531     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1532     Abbv->Add(AbbrevOpToUse);
1533     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1534 
1535     for (const auto P : M.getSourceFileName())
1536       Vals.push_back((unsigned char)P);
1537 
1538     // Emit the finished record.
1539     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
1540     Vals.clear();
1541   }
1542 
1543   // Emit the global variable information.
1544   for (const GlobalVariable &GV : M.globals()) {
1545     unsigned AbbrevToUse = 0;
1546 
1547     // GLOBALVAR: [strtab offset, strtab size, type, isconst, initid,
1548     //             linkage, alignment, section, visibility, threadlocal,
1549     //             unnamed_addr, externally_initialized, dllstorageclass,
1550     //             comdat, attributes, DSO_Local, GlobalSanitizer, code_model]
1551     Vals.push_back(addToStrtab(GV.getName()));
1552     Vals.push_back(GV.getName().size());
1553     Vals.push_back(VE.getTypeID(GV.getValueType()));
1554     Vals.push_back(GV.getType()->getAddressSpace() << 2 | 2 | GV.isConstant());
1555     Vals.push_back(GV.isDeclaration() ? 0 :
1556                    (VE.getValueID(GV.getInitializer()) + 1));
1557     Vals.push_back(getEncodedLinkage(GV));
1558     Vals.push_back(getEncodedAlign(GV.getAlign()));
1559     Vals.push_back(GV.hasSection() ? SectionMap[std::string(GV.getSection())]
1560                                    : 0);
1561     if (GV.isThreadLocal() ||
1562         GV.getVisibility() != GlobalValue::DefaultVisibility ||
1563         GV.getUnnamedAddr() != GlobalValue::UnnamedAddr::None ||
1564         GV.isExternallyInitialized() ||
1565         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
1566         GV.hasComdat() || GV.hasAttributes() || GV.isDSOLocal() ||
1567         GV.hasPartition() || GV.hasSanitizerMetadata() || GV.getCodeModel()) {
1568       Vals.push_back(getEncodedVisibility(GV));
1569       Vals.push_back(getEncodedThreadLocalMode(GV));
1570       Vals.push_back(getEncodedUnnamedAddr(GV));
1571       Vals.push_back(GV.isExternallyInitialized());
1572       Vals.push_back(getEncodedDLLStorageClass(GV));
1573       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
1574 
1575       auto AL = GV.getAttributesAsList(AttributeList::FunctionIndex);
1576       Vals.push_back(VE.getAttributeListID(AL));
1577 
1578       Vals.push_back(GV.isDSOLocal());
1579       Vals.push_back(addToStrtab(GV.getPartition()));
1580       Vals.push_back(GV.getPartition().size());
1581 
1582       Vals.push_back((GV.hasSanitizerMetadata() ? serializeSanitizerMetadata(
1583                                                       GV.getSanitizerMetadata())
1584                                                 : 0));
1585       Vals.push_back(GV.getCodeModelRaw());
1586     } else {
1587       AbbrevToUse = SimpleGVarAbbrev;
1588     }
1589 
1590     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
1591     Vals.clear();
1592   }
1593 
1594   // Emit the function proto information.
1595   for (const Function &F : M) {
1596     // FUNCTION:  [strtab offset, strtab size, type, callingconv, isproto,
1597     //             linkage, paramattrs, alignment, section, visibility, gc,
1598     //             unnamed_addr, prologuedata, dllstorageclass, comdat,
1599     //             prefixdata, personalityfn, DSO_Local, addrspace]
1600     Vals.push_back(addToStrtab(F.getName()));
1601     Vals.push_back(F.getName().size());
1602     Vals.push_back(VE.getTypeID(F.getFunctionType()));
1603     Vals.push_back(F.getCallingConv());
1604     Vals.push_back(F.isDeclaration());
1605     Vals.push_back(getEncodedLinkage(F));
1606     Vals.push_back(VE.getAttributeListID(F.getAttributes()));
1607     Vals.push_back(getEncodedAlign(F.getAlign()));
1608     Vals.push_back(F.hasSection() ? SectionMap[std::string(F.getSection())]
1609                                   : 0);
1610     Vals.push_back(getEncodedVisibility(F));
1611     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
1612     Vals.push_back(getEncodedUnnamedAddr(F));
1613     Vals.push_back(F.hasPrologueData() ? (VE.getValueID(F.getPrologueData()) + 1)
1614                                        : 0);
1615     Vals.push_back(getEncodedDLLStorageClass(F));
1616     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
1617     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
1618                                      : 0);
1619     Vals.push_back(
1620         F.hasPersonalityFn() ? (VE.getValueID(F.getPersonalityFn()) + 1) : 0);
1621 
1622     Vals.push_back(F.isDSOLocal());
1623     Vals.push_back(F.getAddressSpace());
1624     Vals.push_back(addToStrtab(F.getPartition()));
1625     Vals.push_back(F.getPartition().size());
1626 
1627     unsigned AbbrevToUse = 0;
1628     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
1629     Vals.clear();
1630   }
1631 
1632   // Emit the alias information.
1633   for (const GlobalAlias &A : M.aliases()) {
1634     // ALIAS: [strtab offset, strtab size, alias type, aliasee val#, linkage,
1635     //         visibility, dllstorageclass, threadlocal, unnamed_addr,
1636     //         DSO_Local]
1637     Vals.push_back(addToStrtab(A.getName()));
1638     Vals.push_back(A.getName().size());
1639     Vals.push_back(VE.getTypeID(A.getValueType()));
1640     Vals.push_back(A.getType()->getAddressSpace());
1641     Vals.push_back(VE.getValueID(A.getAliasee()));
1642     Vals.push_back(getEncodedLinkage(A));
1643     Vals.push_back(getEncodedVisibility(A));
1644     Vals.push_back(getEncodedDLLStorageClass(A));
1645     Vals.push_back(getEncodedThreadLocalMode(A));
1646     Vals.push_back(getEncodedUnnamedAddr(A));
1647     Vals.push_back(A.isDSOLocal());
1648     Vals.push_back(addToStrtab(A.getPartition()));
1649     Vals.push_back(A.getPartition().size());
1650 
1651     unsigned AbbrevToUse = 0;
1652     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
1653     Vals.clear();
1654   }
1655 
1656   // Emit the ifunc information.
1657   for (const GlobalIFunc &I : M.ifuncs()) {
1658     // IFUNC: [strtab offset, strtab size, ifunc type, address space, resolver
1659     //         val#, linkage, visibility, DSO_Local]
1660     Vals.push_back(addToStrtab(I.getName()));
1661     Vals.push_back(I.getName().size());
1662     Vals.push_back(VE.getTypeID(I.getValueType()));
1663     Vals.push_back(I.getType()->getAddressSpace());
1664     Vals.push_back(VE.getValueID(I.getResolver()));
1665     Vals.push_back(getEncodedLinkage(I));
1666     Vals.push_back(getEncodedVisibility(I));
1667     Vals.push_back(I.isDSOLocal());
1668     Vals.push_back(addToStrtab(I.getPartition()));
1669     Vals.push_back(I.getPartition().size());
1670     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
1671     Vals.clear();
1672   }
1673 
1674   writeValueSymbolTableForwardDecl();
1675 }
1676 
1677 static uint64_t getOptimizationFlags(const Value *V) {
1678   uint64_t Flags = 0;
1679 
1680   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
1681     if (OBO->hasNoSignedWrap())
1682       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
1683     if (OBO->hasNoUnsignedWrap())
1684       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
1685   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
1686     if (PEO->isExact())
1687       Flags |= 1 << bitc::PEO_EXACT;
1688   } else if (const auto *PDI = dyn_cast<PossiblyDisjointInst>(V)) {
1689     if (PDI->isDisjoint())
1690       Flags |= 1 << bitc::PDI_DISJOINT;
1691   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
1692     if (FPMO->hasAllowReassoc())
1693       Flags |= bitc::AllowReassoc;
1694     if (FPMO->hasNoNaNs())
1695       Flags |= bitc::NoNaNs;
1696     if (FPMO->hasNoInfs())
1697       Flags |= bitc::NoInfs;
1698     if (FPMO->hasNoSignedZeros())
1699       Flags |= bitc::NoSignedZeros;
1700     if (FPMO->hasAllowReciprocal())
1701       Flags |= bitc::AllowReciprocal;
1702     if (FPMO->hasAllowContract())
1703       Flags |= bitc::AllowContract;
1704     if (FPMO->hasApproxFunc())
1705       Flags |= bitc::ApproxFunc;
1706   } else if (const auto *NNI = dyn_cast<PossiblyNonNegInst>(V)) {
1707     if (NNI->hasNonNeg())
1708       Flags |= 1 << bitc::PNNI_NON_NEG;
1709   } else if (const auto *TI = dyn_cast<TruncInst>(V)) {
1710     if (TI->hasNoSignedWrap())
1711       Flags |= 1 << bitc::TIO_NO_SIGNED_WRAP;
1712     if (TI->hasNoUnsignedWrap())
1713       Flags |= 1 << bitc::TIO_NO_UNSIGNED_WRAP;
1714   } else if (const auto *GEP = dyn_cast<GEPOperator>(V)) {
1715     if (GEP->isInBounds())
1716       Flags |= 1 << bitc::GEP_INBOUNDS;
1717     if (GEP->hasNoUnsignedSignedWrap())
1718       Flags |= 1 << bitc::GEP_NUSW;
1719     if (GEP->hasNoUnsignedWrap())
1720       Flags |= 1 << bitc::GEP_NUW;
1721   } else if (const auto *ICmp = dyn_cast<ICmpInst>(V)) {
1722     if (ICmp->hasSameSign())
1723       Flags |= 1 << bitc::ICMP_SAME_SIGN;
1724   }
1725 
1726   return Flags;
1727 }
1728 
1729 void ModuleBitcodeWriter::writeValueAsMetadata(
1730     const ValueAsMetadata *MD, SmallVectorImpl<uint64_t> &Record) {
1731   // Mimic an MDNode with a value as one operand.
1732   Value *V = MD->getValue();
1733   Record.push_back(VE.getTypeID(V->getType()));
1734   Record.push_back(VE.getValueID(V));
1735   Stream.EmitRecord(bitc::METADATA_VALUE, Record, 0);
1736   Record.clear();
1737 }
1738 
1739 void ModuleBitcodeWriter::writeMDTuple(const MDTuple *N,
1740                                        SmallVectorImpl<uint64_t> &Record,
1741                                        unsigned Abbrev) {
1742   for (const MDOperand &MDO : N->operands()) {
1743     Metadata *MD = MDO;
1744     assert(!(MD && isa<LocalAsMetadata>(MD)) &&
1745            "Unexpected function-local metadata");
1746     Record.push_back(VE.getMetadataOrNullID(MD));
1747   }
1748   Stream.EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
1749                                     : bitc::METADATA_NODE,
1750                     Record, Abbrev);
1751   Record.clear();
1752 }
1753 
1754 unsigned ModuleBitcodeWriter::createDILocationAbbrev() {
1755   // Assume the column is usually under 128, and always output the inlined-at
1756   // location (it's never more expensive than building an array size 1).
1757   auto Abbv = std::make_shared<BitCodeAbbrev>();
1758   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
1759   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1760   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1761   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1762   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1763   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1764   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1765   return Stream.EmitAbbrev(std::move(Abbv));
1766 }
1767 
1768 void ModuleBitcodeWriter::writeDILocation(const DILocation *N,
1769                                           SmallVectorImpl<uint64_t> &Record,
1770                                           unsigned &Abbrev) {
1771   if (!Abbrev)
1772     Abbrev = createDILocationAbbrev();
1773 
1774   Record.push_back(N->isDistinct());
1775   Record.push_back(N->getLine());
1776   Record.push_back(N->getColumn());
1777   Record.push_back(VE.getMetadataID(N->getScope()));
1778   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
1779   Record.push_back(N->isImplicitCode());
1780 
1781   Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
1782   Record.clear();
1783 }
1784 
1785 unsigned ModuleBitcodeWriter::createGenericDINodeAbbrev() {
1786   // Assume the column is usually under 128, and always output the inlined-at
1787   // location (it's never more expensive than building an array size 1).
1788   auto Abbv = std::make_shared<BitCodeAbbrev>();
1789   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
1790   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1791   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1792   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1793   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1794   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1795   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1796   return Stream.EmitAbbrev(std::move(Abbv));
1797 }
1798 
1799 void ModuleBitcodeWriter::writeGenericDINode(const GenericDINode *N,
1800                                              SmallVectorImpl<uint64_t> &Record,
1801                                              unsigned &Abbrev) {
1802   if (!Abbrev)
1803     Abbrev = createGenericDINodeAbbrev();
1804 
1805   Record.push_back(N->isDistinct());
1806   Record.push_back(N->getTag());
1807   Record.push_back(0); // Per-tag version field; unused for now.
1808 
1809   for (auto &I : N->operands())
1810     Record.push_back(VE.getMetadataOrNullID(I));
1811 
1812   Stream.EmitRecord(bitc::METADATA_GENERIC_DEBUG, Record, Abbrev);
1813   Record.clear();
1814 }
1815 
1816 void ModuleBitcodeWriter::writeDISubrange(const DISubrange *N,
1817                                           SmallVectorImpl<uint64_t> &Record,
1818                                           unsigned Abbrev) {
1819   const uint64_t Version = 2 << 1;
1820   Record.push_back((uint64_t)N->isDistinct() | Version);
1821   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1822   Record.push_back(VE.getMetadataOrNullID(N->getRawLowerBound()));
1823   Record.push_back(VE.getMetadataOrNullID(N->getRawUpperBound()));
1824   Record.push_back(VE.getMetadataOrNullID(N->getRawStride()));
1825 
1826   Stream.EmitRecord(bitc::METADATA_SUBRANGE, Record, Abbrev);
1827   Record.clear();
1828 }
1829 
1830 void ModuleBitcodeWriter::writeDIGenericSubrange(
1831     const DIGenericSubrange *N, SmallVectorImpl<uint64_t> &Record,
1832     unsigned Abbrev) {
1833   Record.push_back((uint64_t)N->isDistinct());
1834   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1835   Record.push_back(VE.getMetadataOrNullID(N->getRawLowerBound()));
1836   Record.push_back(VE.getMetadataOrNullID(N->getRawUpperBound()));
1837   Record.push_back(VE.getMetadataOrNullID(N->getRawStride()));
1838 
1839   Stream.EmitRecord(bitc::METADATA_GENERIC_SUBRANGE, Record, Abbrev);
1840   Record.clear();
1841 }
1842 
1843 void ModuleBitcodeWriter::writeDIEnumerator(const DIEnumerator *N,
1844                                             SmallVectorImpl<uint64_t> &Record,
1845                                             unsigned Abbrev) {
1846   const uint64_t IsBigInt = 1 << 2;
1847   Record.push_back(IsBigInt | (N->isUnsigned() << 1) | N->isDistinct());
1848   Record.push_back(N->getValue().getBitWidth());
1849   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1850   emitWideAPInt(Record, N->getValue());
1851 
1852   Stream.EmitRecord(bitc::METADATA_ENUMERATOR, Record, Abbrev);
1853   Record.clear();
1854 }
1855 
1856 void ModuleBitcodeWriter::writeDIBasicType(const DIBasicType *N,
1857                                            SmallVectorImpl<uint64_t> &Record,
1858                                            unsigned Abbrev) {
1859   Record.push_back(N->isDistinct());
1860   Record.push_back(N->getTag());
1861   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1862   Record.push_back(N->getSizeInBits());
1863   Record.push_back(N->getAlignInBits());
1864   Record.push_back(N->getEncoding());
1865   Record.push_back(N->getFlags());
1866   Record.push_back(N->getNumExtraInhabitants());
1867 
1868   Stream.EmitRecord(bitc::METADATA_BASIC_TYPE, Record, Abbrev);
1869   Record.clear();
1870 }
1871 
1872 void ModuleBitcodeWriter::writeDIStringType(const DIStringType *N,
1873                                             SmallVectorImpl<uint64_t> &Record,
1874                                             unsigned Abbrev) {
1875   Record.push_back(N->isDistinct());
1876   Record.push_back(N->getTag());
1877   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1878   Record.push_back(VE.getMetadataOrNullID(N->getStringLength()));
1879   Record.push_back(VE.getMetadataOrNullID(N->getStringLengthExp()));
1880   Record.push_back(VE.getMetadataOrNullID(N->getStringLocationExp()));
1881   Record.push_back(N->getSizeInBits());
1882   Record.push_back(N->getAlignInBits());
1883   Record.push_back(N->getEncoding());
1884 
1885   Stream.EmitRecord(bitc::METADATA_STRING_TYPE, Record, Abbrev);
1886   Record.clear();
1887 }
1888 
1889 void ModuleBitcodeWriter::writeDIDerivedType(const DIDerivedType *N,
1890                                              SmallVectorImpl<uint64_t> &Record,
1891                                              unsigned Abbrev) {
1892   Record.push_back(N->isDistinct());
1893   Record.push_back(N->getTag());
1894   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1895   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1896   Record.push_back(N->getLine());
1897   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1898   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1899   Record.push_back(N->getSizeInBits());
1900   Record.push_back(N->getAlignInBits());
1901   Record.push_back(N->getOffsetInBits());
1902   Record.push_back(N->getFlags());
1903   Record.push_back(VE.getMetadataOrNullID(N->getExtraData()));
1904 
1905   // DWARF address space is encoded as N->getDWARFAddressSpace() + 1. 0 means
1906   // that there is no DWARF address space associated with DIDerivedType.
1907   if (const auto &DWARFAddressSpace = N->getDWARFAddressSpace())
1908     Record.push_back(*DWARFAddressSpace + 1);
1909   else
1910     Record.push_back(0);
1911 
1912   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1913 
1914   if (auto PtrAuthData = N->getPtrAuthData())
1915     Record.push_back(PtrAuthData->RawData);
1916   else
1917     Record.push_back(0);
1918 
1919   Stream.EmitRecord(bitc::METADATA_DERIVED_TYPE, Record, Abbrev);
1920   Record.clear();
1921 }
1922 
1923 void ModuleBitcodeWriter::writeDICompositeType(
1924     const DICompositeType *N, SmallVectorImpl<uint64_t> &Record,
1925     unsigned Abbrev) {
1926   const unsigned IsNotUsedInOldTypeRef = 0x2;
1927   Record.push_back(IsNotUsedInOldTypeRef | (unsigned)N->isDistinct());
1928   Record.push_back(N->getTag());
1929   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1930   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1931   Record.push_back(N->getLine());
1932   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1933   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1934   Record.push_back(N->getSizeInBits());
1935   Record.push_back(N->getAlignInBits());
1936   Record.push_back(N->getOffsetInBits());
1937   Record.push_back(N->getFlags());
1938   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1939   Record.push_back(N->getRuntimeLang());
1940   Record.push_back(VE.getMetadataOrNullID(N->getVTableHolder()));
1941   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1942   Record.push_back(VE.getMetadataOrNullID(N->getRawIdentifier()));
1943   Record.push_back(VE.getMetadataOrNullID(N->getDiscriminator()));
1944   Record.push_back(VE.getMetadataOrNullID(N->getRawDataLocation()));
1945   Record.push_back(VE.getMetadataOrNullID(N->getRawAssociated()));
1946   Record.push_back(VE.getMetadataOrNullID(N->getRawAllocated()));
1947   Record.push_back(VE.getMetadataOrNullID(N->getRawRank()));
1948   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1949   Record.push_back(N->getNumExtraInhabitants());
1950 
1951   Stream.EmitRecord(bitc::METADATA_COMPOSITE_TYPE, Record, Abbrev);
1952   Record.clear();
1953 }
1954 
1955 void ModuleBitcodeWriter::writeDISubroutineType(
1956     const DISubroutineType *N, SmallVectorImpl<uint64_t> &Record,
1957     unsigned Abbrev) {
1958   const unsigned HasNoOldTypeRefs = 0x2;
1959   Record.push_back(HasNoOldTypeRefs | (unsigned)N->isDistinct());
1960   Record.push_back(N->getFlags());
1961   Record.push_back(VE.getMetadataOrNullID(N->getTypeArray().get()));
1962   Record.push_back(N->getCC());
1963 
1964   Stream.EmitRecord(bitc::METADATA_SUBROUTINE_TYPE, Record, Abbrev);
1965   Record.clear();
1966 }
1967 
1968 void ModuleBitcodeWriter::writeDIFile(const DIFile *N,
1969                                       SmallVectorImpl<uint64_t> &Record,
1970                                       unsigned Abbrev) {
1971   Record.push_back(N->isDistinct());
1972   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
1973   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
1974   if (N->getRawChecksum()) {
1975     Record.push_back(N->getRawChecksum()->Kind);
1976     Record.push_back(VE.getMetadataOrNullID(N->getRawChecksum()->Value));
1977   } else {
1978     // Maintain backwards compatibility with the old internal representation of
1979     // CSK_None in ChecksumKind by writing nulls here when Checksum is None.
1980     Record.push_back(0);
1981     Record.push_back(VE.getMetadataOrNullID(nullptr));
1982   }
1983   auto Source = N->getRawSource();
1984   if (Source)
1985     Record.push_back(VE.getMetadataOrNullID(Source));
1986 
1987   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
1988   Record.clear();
1989 }
1990 
1991 void ModuleBitcodeWriter::writeDICompileUnit(const DICompileUnit *N,
1992                                              SmallVectorImpl<uint64_t> &Record,
1993                                              unsigned Abbrev) {
1994   assert(N->isDistinct() && "Expected distinct compile units");
1995   Record.push_back(/* IsDistinct */ true);
1996   Record.push_back(N->getSourceLanguage());
1997   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1998   Record.push_back(VE.getMetadataOrNullID(N->getRawProducer()));
1999   Record.push_back(N->isOptimized());
2000   Record.push_back(VE.getMetadataOrNullID(N->getRawFlags()));
2001   Record.push_back(N->getRuntimeVersion());
2002   Record.push_back(VE.getMetadataOrNullID(N->getRawSplitDebugFilename()));
2003   Record.push_back(N->getEmissionKind());
2004   Record.push_back(VE.getMetadataOrNullID(N->getEnumTypes().get()));
2005   Record.push_back(VE.getMetadataOrNullID(N->getRetainedTypes().get()));
2006   Record.push_back(/* subprograms */ 0);
2007   Record.push_back(VE.getMetadataOrNullID(N->getGlobalVariables().get()));
2008   Record.push_back(VE.getMetadataOrNullID(N->getImportedEntities().get()));
2009   Record.push_back(N->getDWOId());
2010   Record.push_back(VE.getMetadataOrNullID(N->getMacros().get()));
2011   Record.push_back(N->getSplitDebugInlining());
2012   Record.push_back(N->getDebugInfoForProfiling());
2013   Record.push_back((unsigned)N->getNameTableKind());
2014   Record.push_back(N->getRangesBaseAddress());
2015   Record.push_back(VE.getMetadataOrNullID(N->getRawSysRoot()));
2016   Record.push_back(VE.getMetadataOrNullID(N->getRawSDK()));
2017 
2018   Stream.EmitRecord(bitc::METADATA_COMPILE_UNIT, Record, Abbrev);
2019   Record.clear();
2020 }
2021 
2022 void ModuleBitcodeWriter::writeDISubprogram(const DISubprogram *N,
2023                                             SmallVectorImpl<uint64_t> &Record,
2024                                             unsigned Abbrev) {
2025   const uint64_t HasUnitFlag = 1 << 1;
2026   const uint64_t HasSPFlagsFlag = 1 << 2;
2027   Record.push_back(uint64_t(N->isDistinct()) | HasUnitFlag | HasSPFlagsFlag);
2028   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2029   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2030   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
2031   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2032   Record.push_back(N->getLine());
2033   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2034   Record.push_back(N->getScopeLine());
2035   Record.push_back(VE.getMetadataOrNullID(N->getContainingType()));
2036   Record.push_back(N->getSPFlags());
2037   Record.push_back(N->getVirtualIndex());
2038   Record.push_back(N->getFlags());
2039   Record.push_back(VE.getMetadataOrNullID(N->getRawUnit()));
2040   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
2041   Record.push_back(VE.getMetadataOrNullID(N->getDeclaration()));
2042   Record.push_back(VE.getMetadataOrNullID(N->getRetainedNodes().get()));
2043   Record.push_back(N->getThisAdjustment());
2044   Record.push_back(VE.getMetadataOrNullID(N->getThrownTypes().get()));
2045   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
2046   Record.push_back(VE.getMetadataOrNullID(N->getRawTargetFuncName()));
2047 
2048   Stream.EmitRecord(bitc::METADATA_SUBPROGRAM, Record, Abbrev);
2049   Record.clear();
2050 }
2051 
2052 void ModuleBitcodeWriter::writeDILexicalBlock(const DILexicalBlock *N,
2053                                               SmallVectorImpl<uint64_t> &Record,
2054                                               unsigned Abbrev) {
2055   Record.push_back(N->isDistinct());
2056   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2057   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2058   Record.push_back(N->getLine());
2059   Record.push_back(N->getColumn());
2060 
2061   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK, Record, Abbrev);
2062   Record.clear();
2063 }
2064 
2065 void ModuleBitcodeWriter::writeDILexicalBlockFile(
2066     const DILexicalBlockFile *N, SmallVectorImpl<uint64_t> &Record,
2067     unsigned Abbrev) {
2068   Record.push_back(N->isDistinct());
2069   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2070   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2071   Record.push_back(N->getDiscriminator());
2072 
2073   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK_FILE, Record, Abbrev);
2074   Record.clear();
2075 }
2076 
2077 void ModuleBitcodeWriter::writeDICommonBlock(const DICommonBlock *N,
2078                                              SmallVectorImpl<uint64_t> &Record,
2079                                              unsigned Abbrev) {
2080   Record.push_back(N->isDistinct());
2081   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2082   Record.push_back(VE.getMetadataOrNullID(N->getDecl()));
2083   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2084   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2085   Record.push_back(N->getLineNo());
2086 
2087   Stream.EmitRecord(bitc::METADATA_COMMON_BLOCK, Record, Abbrev);
2088   Record.clear();
2089 }
2090 
2091 void ModuleBitcodeWriter::writeDINamespace(const DINamespace *N,
2092                                            SmallVectorImpl<uint64_t> &Record,
2093                                            unsigned Abbrev) {
2094   Record.push_back(N->isDistinct() | N->getExportSymbols() << 1);
2095   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2096   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2097 
2098   Stream.EmitRecord(bitc::METADATA_NAMESPACE, Record, Abbrev);
2099   Record.clear();
2100 }
2101 
2102 void ModuleBitcodeWriter::writeDIMacro(const DIMacro *N,
2103                                        SmallVectorImpl<uint64_t> &Record,
2104                                        unsigned Abbrev) {
2105   Record.push_back(N->isDistinct());
2106   Record.push_back(N->getMacinfoType());
2107   Record.push_back(N->getLine());
2108   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2109   Record.push_back(VE.getMetadataOrNullID(N->getRawValue()));
2110 
2111   Stream.EmitRecord(bitc::METADATA_MACRO, Record, Abbrev);
2112   Record.clear();
2113 }
2114 
2115 void ModuleBitcodeWriter::writeDIMacroFile(const DIMacroFile *N,
2116                                            SmallVectorImpl<uint64_t> &Record,
2117                                            unsigned Abbrev) {
2118   Record.push_back(N->isDistinct());
2119   Record.push_back(N->getMacinfoType());
2120   Record.push_back(N->getLine());
2121   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2122   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
2123 
2124   Stream.EmitRecord(bitc::METADATA_MACRO_FILE, Record, Abbrev);
2125   Record.clear();
2126 }
2127 
2128 void ModuleBitcodeWriter::writeDIArgList(const DIArgList *N,
2129                                          SmallVectorImpl<uint64_t> &Record) {
2130   Record.reserve(N->getArgs().size());
2131   for (ValueAsMetadata *MD : N->getArgs())
2132     Record.push_back(VE.getMetadataID(MD));
2133 
2134   Stream.EmitRecord(bitc::METADATA_ARG_LIST, Record);
2135   Record.clear();
2136 }
2137 
2138 void ModuleBitcodeWriter::writeDIModule(const DIModule *N,
2139                                         SmallVectorImpl<uint64_t> &Record,
2140                                         unsigned Abbrev) {
2141   Record.push_back(N->isDistinct());
2142   for (auto &I : N->operands())
2143     Record.push_back(VE.getMetadataOrNullID(I));
2144   Record.push_back(N->getLineNo());
2145   Record.push_back(N->getIsDecl());
2146 
2147   Stream.EmitRecord(bitc::METADATA_MODULE, Record, Abbrev);
2148   Record.clear();
2149 }
2150 
2151 void ModuleBitcodeWriter::writeDIAssignID(const DIAssignID *N,
2152                                           SmallVectorImpl<uint64_t> &Record,
2153                                           unsigned Abbrev) {
2154   // There are no arguments for this metadata type.
2155   Record.push_back(N->isDistinct());
2156   Stream.EmitRecord(bitc::METADATA_ASSIGN_ID, Record, Abbrev);
2157   Record.clear();
2158 }
2159 
2160 void ModuleBitcodeWriter::writeDITemplateTypeParameter(
2161     const DITemplateTypeParameter *N, SmallVectorImpl<uint64_t> &Record,
2162     unsigned Abbrev) {
2163   Record.push_back(N->isDistinct());
2164   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2165   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2166   Record.push_back(N->isDefault());
2167 
2168   Stream.EmitRecord(bitc::METADATA_TEMPLATE_TYPE, Record, Abbrev);
2169   Record.clear();
2170 }
2171 
2172 void ModuleBitcodeWriter::writeDITemplateValueParameter(
2173     const DITemplateValueParameter *N, SmallVectorImpl<uint64_t> &Record,
2174     unsigned Abbrev) {
2175   Record.push_back(N->isDistinct());
2176   Record.push_back(N->getTag());
2177   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2178   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2179   Record.push_back(N->isDefault());
2180   Record.push_back(VE.getMetadataOrNullID(N->getValue()));
2181 
2182   Stream.EmitRecord(bitc::METADATA_TEMPLATE_VALUE, Record, Abbrev);
2183   Record.clear();
2184 }
2185 
2186 void ModuleBitcodeWriter::writeDIGlobalVariable(
2187     const DIGlobalVariable *N, SmallVectorImpl<uint64_t> &Record,
2188     unsigned Abbrev) {
2189   const uint64_t Version = 2 << 1;
2190   Record.push_back((uint64_t)N->isDistinct() | Version);
2191   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2192   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2193   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
2194   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2195   Record.push_back(N->getLine());
2196   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2197   Record.push_back(N->isLocalToUnit());
2198   Record.push_back(N->isDefinition());
2199   Record.push_back(VE.getMetadataOrNullID(N->getStaticDataMemberDeclaration()));
2200   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams()));
2201   Record.push_back(N->getAlignInBits());
2202   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
2203 
2204   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR, Record, Abbrev);
2205   Record.clear();
2206 }
2207 
2208 void ModuleBitcodeWriter::writeDILocalVariable(
2209     const DILocalVariable *N, SmallVectorImpl<uint64_t> &Record,
2210     unsigned Abbrev) {
2211   // In order to support all possible bitcode formats in BitcodeReader we need
2212   // to distinguish the following cases:
2213   // 1) Record has no artificial tag (Record[1]),
2214   //   has no obsolete inlinedAt field (Record[9]).
2215   //   In this case Record size will be 8, HasAlignment flag is false.
2216   // 2) Record has artificial tag (Record[1]),
2217   //   has no obsolete inlignedAt field (Record[9]).
2218   //   In this case Record size will be 9, HasAlignment flag is false.
2219   // 3) Record has both artificial tag (Record[1]) and
2220   //   obsolete inlignedAt field (Record[9]).
2221   //   In this case Record size will be 10, HasAlignment flag is false.
2222   // 4) Record has neither artificial tag, nor inlignedAt field, but
2223   //   HasAlignment flag is true and Record[8] contains alignment value.
2224   const uint64_t HasAlignmentFlag = 1 << 1;
2225   Record.push_back((uint64_t)N->isDistinct() | HasAlignmentFlag);
2226   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2227   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2228   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2229   Record.push_back(N->getLine());
2230   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2231   Record.push_back(N->getArg());
2232   Record.push_back(N->getFlags());
2233   Record.push_back(N->getAlignInBits());
2234   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
2235 
2236   Stream.EmitRecord(bitc::METADATA_LOCAL_VAR, Record, Abbrev);
2237   Record.clear();
2238 }
2239 
2240 void ModuleBitcodeWriter::writeDILabel(
2241     const DILabel *N, SmallVectorImpl<uint64_t> &Record,
2242     unsigned Abbrev) {
2243   Record.push_back((uint64_t)N->isDistinct());
2244   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2245   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2246   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2247   Record.push_back(N->getLine());
2248 
2249   Stream.EmitRecord(bitc::METADATA_LABEL, Record, Abbrev);
2250   Record.clear();
2251 }
2252 
2253 void ModuleBitcodeWriter::writeDIExpression(const DIExpression *N,
2254                                             SmallVectorImpl<uint64_t> &Record,
2255                                             unsigned Abbrev) {
2256   Record.reserve(N->getElements().size() + 1);
2257   const uint64_t Version = 3 << 1;
2258   Record.push_back((uint64_t)N->isDistinct() | Version);
2259   Record.append(N->elements_begin(), N->elements_end());
2260 
2261   Stream.EmitRecord(bitc::METADATA_EXPRESSION, Record, Abbrev);
2262   Record.clear();
2263 }
2264 
2265 void ModuleBitcodeWriter::writeDIGlobalVariableExpression(
2266     const DIGlobalVariableExpression *N, SmallVectorImpl<uint64_t> &Record,
2267     unsigned Abbrev) {
2268   Record.push_back(N->isDistinct());
2269   Record.push_back(VE.getMetadataOrNullID(N->getVariable()));
2270   Record.push_back(VE.getMetadataOrNullID(N->getExpression()));
2271 
2272   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR_EXPR, Record, Abbrev);
2273   Record.clear();
2274 }
2275 
2276 void ModuleBitcodeWriter::writeDIObjCProperty(const DIObjCProperty *N,
2277                                               SmallVectorImpl<uint64_t> &Record,
2278                                               unsigned Abbrev) {
2279   Record.push_back(N->isDistinct());
2280   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2281   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2282   Record.push_back(N->getLine());
2283   Record.push_back(VE.getMetadataOrNullID(N->getRawSetterName()));
2284   Record.push_back(VE.getMetadataOrNullID(N->getRawGetterName()));
2285   Record.push_back(N->getAttributes());
2286   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2287 
2288   Stream.EmitRecord(bitc::METADATA_OBJC_PROPERTY, Record, Abbrev);
2289   Record.clear();
2290 }
2291 
2292 void ModuleBitcodeWriter::writeDIImportedEntity(
2293     const DIImportedEntity *N, SmallVectorImpl<uint64_t> &Record,
2294     unsigned Abbrev) {
2295   Record.push_back(N->isDistinct());
2296   Record.push_back(N->getTag());
2297   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2298   Record.push_back(VE.getMetadataOrNullID(N->getEntity()));
2299   Record.push_back(N->getLine());
2300   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2301   Record.push_back(VE.getMetadataOrNullID(N->getRawFile()));
2302   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
2303 
2304   Stream.EmitRecord(bitc::METADATA_IMPORTED_ENTITY, Record, Abbrev);
2305   Record.clear();
2306 }
2307 
2308 unsigned ModuleBitcodeWriter::createNamedMetadataAbbrev() {
2309   auto Abbv = std::make_shared<BitCodeAbbrev>();
2310   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
2311   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2312   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2313   return Stream.EmitAbbrev(std::move(Abbv));
2314 }
2315 
2316 void ModuleBitcodeWriter::writeNamedMetadata(
2317     SmallVectorImpl<uint64_t> &Record) {
2318   if (M.named_metadata_empty())
2319     return;
2320 
2321   unsigned Abbrev = createNamedMetadataAbbrev();
2322   for (const NamedMDNode &NMD : M.named_metadata()) {
2323     // Write name.
2324     StringRef Str = NMD.getName();
2325     Record.append(Str.bytes_begin(), Str.bytes_end());
2326     Stream.EmitRecord(bitc::METADATA_NAME, Record, Abbrev);
2327     Record.clear();
2328 
2329     // Write named metadata operands.
2330     for (const MDNode *N : NMD.operands())
2331       Record.push_back(VE.getMetadataID(N));
2332     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
2333     Record.clear();
2334   }
2335 }
2336 
2337 unsigned ModuleBitcodeWriter::createMetadataStringsAbbrev() {
2338   auto Abbv = std::make_shared<BitCodeAbbrev>();
2339   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRINGS));
2340   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // # of strings
2341   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // offset to chars
2342   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
2343   return Stream.EmitAbbrev(std::move(Abbv));
2344 }
2345 
2346 /// Write out a record for MDString.
2347 ///
2348 /// All the metadata strings in a metadata block are emitted in a single
2349 /// record.  The sizes and strings themselves are shoved into a blob.
2350 void ModuleBitcodeWriter::writeMetadataStrings(
2351     ArrayRef<const Metadata *> Strings, SmallVectorImpl<uint64_t> &Record) {
2352   if (Strings.empty())
2353     return;
2354 
2355   // Start the record with the number of strings.
2356   Record.push_back(bitc::METADATA_STRINGS);
2357   Record.push_back(Strings.size());
2358 
2359   // Emit the sizes of the strings in the blob.
2360   SmallString<256> Blob;
2361   {
2362     BitstreamWriter W(Blob);
2363     for (const Metadata *MD : Strings)
2364       W.EmitVBR(cast<MDString>(MD)->getLength(), 6);
2365     W.FlushToWord();
2366   }
2367 
2368   // Add the offset to the strings to the record.
2369   Record.push_back(Blob.size());
2370 
2371   // Add the strings to the blob.
2372   for (const Metadata *MD : Strings)
2373     Blob.append(cast<MDString>(MD)->getString());
2374 
2375   // Emit the final record.
2376   Stream.EmitRecordWithBlob(createMetadataStringsAbbrev(), Record, Blob);
2377   Record.clear();
2378 }
2379 
2380 // Generates an enum to use as an index in the Abbrev array of Metadata record.
2381 enum MetadataAbbrev : unsigned {
2382 #define HANDLE_MDNODE_LEAF(CLASS) CLASS##AbbrevID,
2383 #include "llvm/IR/Metadata.def"
2384   LastPlusOne
2385 };
2386 
2387 void ModuleBitcodeWriter::writeMetadataRecords(
2388     ArrayRef<const Metadata *> MDs, SmallVectorImpl<uint64_t> &Record,
2389     std::vector<unsigned> *MDAbbrevs, std::vector<uint64_t> *IndexPos) {
2390   if (MDs.empty())
2391     return;
2392 
2393   // Initialize MDNode abbreviations.
2394 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
2395 #include "llvm/IR/Metadata.def"
2396 
2397   for (const Metadata *MD : MDs) {
2398     if (IndexPos)
2399       IndexPos->push_back(Stream.GetCurrentBitNo());
2400     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
2401       assert(N->isResolved() && "Expected forward references to be resolved");
2402 
2403       switch (N->getMetadataID()) {
2404       default:
2405         llvm_unreachable("Invalid MDNode subclass");
2406 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
2407   case Metadata::CLASS##Kind:                                                  \
2408     if (MDAbbrevs)                                                             \
2409       write##CLASS(cast<CLASS>(N), Record,                                     \
2410                    (*MDAbbrevs)[MetadataAbbrev::CLASS##AbbrevID]);             \
2411     else                                                                       \
2412       write##CLASS(cast<CLASS>(N), Record, CLASS##Abbrev);                     \
2413     continue;
2414 #include "llvm/IR/Metadata.def"
2415       }
2416     }
2417     if (auto *AL = dyn_cast<DIArgList>(MD)) {
2418       writeDIArgList(AL, Record);
2419       continue;
2420     }
2421     writeValueAsMetadata(cast<ValueAsMetadata>(MD), Record);
2422   }
2423 }
2424 
2425 void ModuleBitcodeWriter::writeModuleMetadata() {
2426   if (!VE.hasMDs() && M.named_metadata_empty())
2427     return;
2428 
2429   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 4);
2430   SmallVector<uint64_t, 64> Record;
2431 
2432   // Emit all abbrevs upfront, so that the reader can jump in the middle of the
2433   // block and load any metadata.
2434   std::vector<unsigned> MDAbbrevs;
2435 
2436   MDAbbrevs.resize(MetadataAbbrev::LastPlusOne);
2437   MDAbbrevs[MetadataAbbrev::DILocationAbbrevID] = createDILocationAbbrev();
2438   MDAbbrevs[MetadataAbbrev::GenericDINodeAbbrevID] =
2439       createGenericDINodeAbbrev();
2440 
2441   auto Abbv = std::make_shared<BitCodeAbbrev>();
2442   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX_OFFSET));
2443   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2444   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2445   unsigned OffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2446 
2447   Abbv = std::make_shared<BitCodeAbbrev>();
2448   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX));
2449   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2450   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2451   unsigned IndexAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2452 
2453   // Emit MDStrings together upfront.
2454   writeMetadataStrings(VE.getMDStrings(), Record);
2455 
2456   // We only emit an index for the metadata record if we have more than a given
2457   // (naive) threshold of metadatas, otherwise it is not worth it.
2458   if (VE.getNonMDStrings().size() > IndexThreshold) {
2459     // Write a placeholder value in for the offset of the metadata index,
2460     // which is written after the records, so that it can include
2461     // the offset of each entry. The placeholder offset will be
2462     // updated after all records are emitted.
2463     uint64_t Vals[] = {0, 0};
2464     Stream.EmitRecord(bitc::METADATA_INDEX_OFFSET, Vals, OffsetAbbrev);
2465   }
2466 
2467   // Compute and save the bit offset to the current position, which will be
2468   // patched when we emit the index later. We can simply subtract the 64-bit
2469   // fixed size from the current bit number to get the location to backpatch.
2470   uint64_t IndexOffsetRecordBitPos = Stream.GetCurrentBitNo();
2471 
2472   // This index will contain the bitpos for each individual record.
2473   std::vector<uint64_t> IndexPos;
2474   IndexPos.reserve(VE.getNonMDStrings().size());
2475 
2476   // Write all the records
2477   writeMetadataRecords(VE.getNonMDStrings(), Record, &MDAbbrevs, &IndexPos);
2478 
2479   if (VE.getNonMDStrings().size() > IndexThreshold) {
2480     // Now that we have emitted all the records we will emit the index. But
2481     // first
2482     // backpatch the forward reference so that the reader can skip the records
2483     // efficiently.
2484     Stream.BackpatchWord64(IndexOffsetRecordBitPos - 64,
2485                            Stream.GetCurrentBitNo() - IndexOffsetRecordBitPos);
2486 
2487     // Delta encode the index.
2488     uint64_t PreviousValue = IndexOffsetRecordBitPos;
2489     for (auto &Elt : IndexPos) {
2490       auto EltDelta = Elt - PreviousValue;
2491       PreviousValue = Elt;
2492       Elt = EltDelta;
2493     }
2494     // Emit the index record.
2495     Stream.EmitRecord(bitc::METADATA_INDEX, IndexPos, IndexAbbrev);
2496     IndexPos.clear();
2497   }
2498 
2499   // Write the named metadata now.
2500   writeNamedMetadata(Record);
2501 
2502   auto AddDeclAttachedMetadata = [&](const GlobalObject &GO) {
2503     SmallVector<uint64_t, 4> Record;
2504     Record.push_back(VE.getValueID(&GO));
2505     pushGlobalMetadataAttachment(Record, GO);
2506     Stream.EmitRecord(bitc::METADATA_GLOBAL_DECL_ATTACHMENT, Record);
2507   };
2508   for (const Function &F : M)
2509     if (F.isDeclaration() && F.hasMetadata())
2510       AddDeclAttachedMetadata(F);
2511   // FIXME: Only store metadata for declarations here, and move data for global
2512   // variable definitions to a separate block (PR28134).
2513   for (const GlobalVariable &GV : M.globals())
2514     if (GV.hasMetadata())
2515       AddDeclAttachedMetadata(GV);
2516 
2517   Stream.ExitBlock();
2518 }
2519 
2520 void ModuleBitcodeWriter::writeFunctionMetadata(const Function &F) {
2521   if (!VE.hasMDs())
2522     return;
2523 
2524   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
2525   SmallVector<uint64_t, 64> Record;
2526   writeMetadataStrings(VE.getMDStrings(), Record);
2527   writeMetadataRecords(VE.getNonMDStrings(), Record);
2528   Stream.ExitBlock();
2529 }
2530 
2531 void ModuleBitcodeWriter::pushGlobalMetadataAttachment(
2532     SmallVectorImpl<uint64_t> &Record, const GlobalObject &GO) {
2533   // [n x [id, mdnode]]
2534   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2535   GO.getAllMetadata(MDs);
2536   for (const auto &I : MDs) {
2537     Record.push_back(I.first);
2538     Record.push_back(VE.getMetadataID(I.second));
2539   }
2540 }
2541 
2542 void ModuleBitcodeWriter::writeFunctionMetadataAttachment(const Function &F) {
2543   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
2544 
2545   SmallVector<uint64_t, 64> Record;
2546 
2547   if (F.hasMetadata()) {
2548     pushGlobalMetadataAttachment(Record, F);
2549     Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2550     Record.clear();
2551   }
2552 
2553   // Write metadata attachments
2554   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
2555   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2556   for (const BasicBlock &BB : F)
2557     for (const Instruction &I : BB) {
2558       MDs.clear();
2559       I.getAllMetadataOtherThanDebugLoc(MDs);
2560 
2561       // If no metadata, ignore instruction.
2562       if (MDs.empty()) continue;
2563 
2564       Record.push_back(VE.getInstructionID(&I));
2565 
2566       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
2567         Record.push_back(MDs[i].first);
2568         Record.push_back(VE.getMetadataID(MDs[i].second));
2569       }
2570       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2571       Record.clear();
2572     }
2573 
2574   Stream.ExitBlock();
2575 }
2576 
2577 void ModuleBitcodeWriter::writeModuleMetadataKinds() {
2578   SmallVector<uint64_t, 64> Record;
2579 
2580   // Write metadata kinds
2581   // METADATA_KIND - [n x [id, name]]
2582   SmallVector<StringRef, 8> Names;
2583   M.getMDKindNames(Names);
2584 
2585   if (Names.empty()) return;
2586 
2587   Stream.EnterSubblock(bitc::METADATA_KIND_BLOCK_ID, 3);
2588 
2589   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
2590     Record.push_back(MDKindID);
2591     StringRef KName = Names[MDKindID];
2592     Record.append(KName.begin(), KName.end());
2593 
2594     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
2595     Record.clear();
2596   }
2597 
2598   Stream.ExitBlock();
2599 }
2600 
2601 void ModuleBitcodeWriter::writeOperandBundleTags() {
2602   // Write metadata kinds
2603   //
2604   // OPERAND_BUNDLE_TAGS_BLOCK_ID : N x OPERAND_BUNDLE_TAG
2605   //
2606   // OPERAND_BUNDLE_TAG - [strchr x N]
2607 
2608   SmallVector<StringRef, 8> Tags;
2609   M.getOperandBundleTags(Tags);
2610 
2611   if (Tags.empty())
2612     return;
2613 
2614   Stream.EnterSubblock(bitc::OPERAND_BUNDLE_TAGS_BLOCK_ID, 3);
2615 
2616   SmallVector<uint64_t, 64> Record;
2617 
2618   for (auto Tag : Tags) {
2619     Record.append(Tag.begin(), Tag.end());
2620 
2621     Stream.EmitRecord(bitc::OPERAND_BUNDLE_TAG, Record, 0);
2622     Record.clear();
2623   }
2624 
2625   Stream.ExitBlock();
2626 }
2627 
2628 void ModuleBitcodeWriter::writeSyncScopeNames() {
2629   SmallVector<StringRef, 8> SSNs;
2630   M.getContext().getSyncScopeNames(SSNs);
2631   if (SSNs.empty())
2632     return;
2633 
2634   Stream.EnterSubblock(bitc::SYNC_SCOPE_NAMES_BLOCK_ID, 2);
2635 
2636   SmallVector<uint64_t, 64> Record;
2637   for (auto SSN : SSNs) {
2638     Record.append(SSN.begin(), SSN.end());
2639     Stream.EmitRecord(bitc::SYNC_SCOPE_NAME, Record, 0);
2640     Record.clear();
2641   }
2642 
2643   Stream.ExitBlock();
2644 }
2645 
2646 void ModuleBitcodeWriter::writeConstants(unsigned FirstVal, unsigned LastVal,
2647                                          bool isGlobal) {
2648   if (FirstVal == LastVal) return;
2649 
2650   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
2651 
2652   unsigned AggregateAbbrev = 0;
2653   unsigned String8Abbrev = 0;
2654   unsigned CString7Abbrev = 0;
2655   unsigned CString6Abbrev = 0;
2656   // If this is a constant pool for the module, emit module-specific abbrevs.
2657   if (isGlobal) {
2658     // Abbrev for CST_CODE_AGGREGATE.
2659     auto Abbv = std::make_shared<BitCodeAbbrev>();
2660     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
2661     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2662     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
2663     AggregateAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2664 
2665     // Abbrev for CST_CODE_STRING.
2666     Abbv = std::make_shared<BitCodeAbbrev>();
2667     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
2668     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2669     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2670     String8Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2671     // Abbrev for CST_CODE_CSTRING.
2672     Abbv = std::make_shared<BitCodeAbbrev>();
2673     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2674     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2675     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2676     CString7Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2677     // Abbrev for CST_CODE_CSTRING.
2678     Abbv = std::make_shared<BitCodeAbbrev>();
2679     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2680     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2681     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2682     CString6Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2683   }
2684 
2685   SmallVector<uint64_t, 64> Record;
2686 
2687   const ValueEnumerator::ValueList &Vals = VE.getValues();
2688   Type *LastTy = nullptr;
2689   for (unsigned i = FirstVal; i != LastVal; ++i) {
2690     const Value *V = Vals[i].first;
2691     // If we need to switch types, do so now.
2692     if (V->getType() != LastTy) {
2693       LastTy = V->getType();
2694       Record.push_back(VE.getTypeID(LastTy));
2695       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
2696                         CONSTANTS_SETTYPE_ABBREV);
2697       Record.clear();
2698     }
2699 
2700     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
2701       Record.push_back(VE.getTypeID(IA->getFunctionType()));
2702       Record.push_back(
2703           unsigned(IA->hasSideEffects()) | unsigned(IA->isAlignStack()) << 1 |
2704           unsigned(IA->getDialect() & 1) << 2 | unsigned(IA->canThrow()) << 3);
2705 
2706       // Add the asm string.
2707       const std::string &AsmStr = IA->getAsmString();
2708       Record.push_back(AsmStr.size());
2709       Record.append(AsmStr.begin(), AsmStr.end());
2710 
2711       // Add the constraint string.
2712       const std::string &ConstraintStr = IA->getConstraintString();
2713       Record.push_back(ConstraintStr.size());
2714       Record.append(ConstraintStr.begin(), ConstraintStr.end());
2715       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
2716       Record.clear();
2717       continue;
2718     }
2719     const Constant *C = cast<Constant>(V);
2720     unsigned Code = -1U;
2721     unsigned AbbrevToUse = 0;
2722     if (C->isNullValue()) {
2723       Code = bitc::CST_CODE_NULL;
2724     } else if (isa<PoisonValue>(C)) {
2725       Code = bitc::CST_CODE_POISON;
2726     } else if (isa<UndefValue>(C)) {
2727       Code = bitc::CST_CODE_UNDEF;
2728     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
2729       if (IV->getBitWidth() <= 64) {
2730         uint64_t V = IV->getSExtValue();
2731         emitSignedInt64(Record, V);
2732         Code = bitc::CST_CODE_INTEGER;
2733         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
2734       } else {                             // Wide integers, > 64 bits in size.
2735         emitWideAPInt(Record, IV->getValue());
2736         Code = bitc::CST_CODE_WIDE_INTEGER;
2737       }
2738     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
2739       Code = bitc::CST_CODE_FLOAT;
2740       Type *Ty = CFP->getType()->getScalarType();
2741       if (Ty->isHalfTy() || Ty->isBFloatTy() || Ty->isFloatTy() ||
2742           Ty->isDoubleTy()) {
2743         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
2744       } else if (Ty->isX86_FP80Ty()) {
2745         // api needed to prevent premature destruction
2746         // bits are not in the same order as a normal i80 APInt, compensate.
2747         APInt api = CFP->getValueAPF().bitcastToAPInt();
2748         const uint64_t *p = api.getRawData();
2749         Record.push_back((p[1] << 48) | (p[0] >> 16));
2750         Record.push_back(p[0] & 0xffffLL);
2751       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
2752         APInt api = CFP->getValueAPF().bitcastToAPInt();
2753         const uint64_t *p = api.getRawData();
2754         Record.push_back(p[0]);
2755         Record.push_back(p[1]);
2756       } else {
2757         assert(0 && "Unknown FP type!");
2758       }
2759     } else if (isa<ConstantDataSequential>(C) &&
2760                cast<ConstantDataSequential>(C)->isString()) {
2761       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
2762       // Emit constant strings specially.
2763       unsigned NumElts = Str->getNumElements();
2764       // If this is a null-terminated string, use the denser CSTRING encoding.
2765       if (Str->isCString()) {
2766         Code = bitc::CST_CODE_CSTRING;
2767         --NumElts;  // Don't encode the null, which isn't allowed by char6.
2768       } else {
2769         Code = bitc::CST_CODE_STRING;
2770         AbbrevToUse = String8Abbrev;
2771       }
2772       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
2773       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
2774       for (unsigned i = 0; i != NumElts; ++i) {
2775         unsigned char V = Str->getElementAsInteger(i);
2776         Record.push_back(V);
2777         isCStr7 &= (V & 128) == 0;
2778         if (isCStrChar6)
2779           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
2780       }
2781 
2782       if (isCStrChar6)
2783         AbbrevToUse = CString6Abbrev;
2784       else if (isCStr7)
2785         AbbrevToUse = CString7Abbrev;
2786     } else if (const ConstantDataSequential *CDS =
2787                   dyn_cast<ConstantDataSequential>(C)) {
2788       Code = bitc::CST_CODE_DATA;
2789       Type *EltTy = CDS->getElementType();
2790       if (isa<IntegerType>(EltTy)) {
2791         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2792           Record.push_back(CDS->getElementAsInteger(i));
2793       } else {
2794         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2795           Record.push_back(
2796               CDS->getElementAsAPFloat(i).bitcastToAPInt().getLimitedValue());
2797       }
2798     } else if (isa<ConstantAggregate>(C)) {
2799       Code = bitc::CST_CODE_AGGREGATE;
2800       for (const Value *Op : C->operands())
2801         Record.push_back(VE.getValueID(Op));
2802       AbbrevToUse = AggregateAbbrev;
2803     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
2804       switch (CE->getOpcode()) {
2805       default:
2806         if (Instruction::isCast(CE->getOpcode())) {
2807           Code = bitc::CST_CODE_CE_CAST;
2808           Record.push_back(getEncodedCastOpcode(CE->getOpcode()));
2809           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2810           Record.push_back(VE.getValueID(C->getOperand(0)));
2811           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
2812         } else {
2813           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
2814           Code = bitc::CST_CODE_CE_BINOP;
2815           Record.push_back(getEncodedBinaryOpcode(CE->getOpcode()));
2816           Record.push_back(VE.getValueID(C->getOperand(0)));
2817           Record.push_back(VE.getValueID(C->getOperand(1)));
2818           uint64_t Flags = getOptimizationFlags(CE);
2819           if (Flags != 0)
2820             Record.push_back(Flags);
2821         }
2822         break;
2823       case Instruction::FNeg: {
2824         assert(CE->getNumOperands() == 1 && "Unknown constant expr!");
2825         Code = bitc::CST_CODE_CE_UNOP;
2826         Record.push_back(getEncodedUnaryOpcode(CE->getOpcode()));
2827         Record.push_back(VE.getValueID(C->getOperand(0)));
2828         uint64_t Flags = getOptimizationFlags(CE);
2829         if (Flags != 0)
2830           Record.push_back(Flags);
2831         break;
2832       }
2833       case Instruction::GetElementPtr: {
2834         Code = bitc::CST_CODE_CE_GEP;
2835         const auto *GO = cast<GEPOperator>(C);
2836         Record.push_back(VE.getTypeID(GO->getSourceElementType()));
2837         Record.push_back(getOptimizationFlags(GO));
2838         if (std::optional<ConstantRange> Range = GO->getInRange()) {
2839           Code = bitc::CST_CODE_CE_GEP_WITH_INRANGE;
2840           emitConstantRange(Record, *Range, /*EmitBitWidth=*/true);
2841         }
2842         for (const Value *Op : CE->operands()) {
2843           Record.push_back(VE.getTypeID(Op->getType()));
2844           Record.push_back(VE.getValueID(Op));
2845         }
2846         break;
2847       }
2848       case Instruction::ExtractElement:
2849         Code = bitc::CST_CODE_CE_EXTRACTELT;
2850         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2851         Record.push_back(VE.getValueID(C->getOperand(0)));
2852         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
2853         Record.push_back(VE.getValueID(C->getOperand(1)));
2854         break;
2855       case Instruction::InsertElement:
2856         Code = bitc::CST_CODE_CE_INSERTELT;
2857         Record.push_back(VE.getValueID(C->getOperand(0)));
2858         Record.push_back(VE.getValueID(C->getOperand(1)));
2859         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
2860         Record.push_back(VE.getValueID(C->getOperand(2)));
2861         break;
2862       case Instruction::ShuffleVector:
2863         // If the return type and argument types are the same, this is a
2864         // standard shufflevector instruction.  If the types are different,
2865         // then the shuffle is widening or truncating the input vectors, and
2866         // the argument type must also be encoded.
2867         if (C->getType() == C->getOperand(0)->getType()) {
2868           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
2869         } else {
2870           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
2871           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2872         }
2873         Record.push_back(VE.getValueID(C->getOperand(0)));
2874         Record.push_back(VE.getValueID(C->getOperand(1)));
2875         Record.push_back(VE.getValueID(CE->getShuffleMaskForBitcode()));
2876         break;
2877       }
2878     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
2879       Code = bitc::CST_CODE_BLOCKADDRESS;
2880       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
2881       Record.push_back(VE.getValueID(BA->getFunction()));
2882       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
2883     } else if (const auto *Equiv = dyn_cast<DSOLocalEquivalent>(C)) {
2884       Code = bitc::CST_CODE_DSO_LOCAL_EQUIVALENT;
2885       Record.push_back(VE.getTypeID(Equiv->getGlobalValue()->getType()));
2886       Record.push_back(VE.getValueID(Equiv->getGlobalValue()));
2887     } else if (const auto *NC = dyn_cast<NoCFIValue>(C)) {
2888       Code = bitc::CST_CODE_NO_CFI_VALUE;
2889       Record.push_back(VE.getTypeID(NC->getGlobalValue()->getType()));
2890       Record.push_back(VE.getValueID(NC->getGlobalValue()));
2891     } else if (const auto *CPA = dyn_cast<ConstantPtrAuth>(C)) {
2892       Code = bitc::CST_CODE_PTRAUTH;
2893       Record.push_back(VE.getValueID(CPA->getPointer()));
2894       Record.push_back(VE.getValueID(CPA->getKey()));
2895       Record.push_back(VE.getValueID(CPA->getDiscriminator()));
2896       Record.push_back(VE.getValueID(CPA->getAddrDiscriminator()));
2897     } else {
2898 #ifndef NDEBUG
2899       C->dump();
2900 #endif
2901       llvm_unreachable("Unknown constant!");
2902     }
2903     Stream.EmitRecord(Code, Record, AbbrevToUse);
2904     Record.clear();
2905   }
2906 
2907   Stream.ExitBlock();
2908 }
2909 
2910 void ModuleBitcodeWriter::writeModuleConstants() {
2911   const ValueEnumerator::ValueList &Vals = VE.getValues();
2912 
2913   // Find the first constant to emit, which is the first non-globalvalue value.
2914   // We know globalvalues have been emitted by WriteModuleInfo.
2915   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
2916     if (!isa<GlobalValue>(Vals[i].first)) {
2917       writeConstants(i, Vals.size(), true);
2918       return;
2919     }
2920   }
2921 }
2922 
2923 /// pushValueAndType - The file has to encode both the value and type id for
2924 /// many values, because we need to know what type to create for forward
2925 /// references.  However, most operands are not forward references, so this type
2926 /// field is not needed.
2927 ///
2928 /// This function adds V's value ID to Vals.  If the value ID is higher than the
2929 /// instruction ID, then it is a forward reference, and it also includes the
2930 /// type ID.  The value ID that is written is encoded relative to the InstID.
2931 bool ModuleBitcodeWriter::pushValueAndType(const Value *V, unsigned InstID,
2932                                            SmallVectorImpl<unsigned> &Vals) {
2933   unsigned ValID = VE.getValueID(V);
2934   // Make encoding relative to the InstID.
2935   Vals.push_back(InstID - ValID);
2936   if (ValID >= InstID) {
2937     Vals.push_back(VE.getTypeID(V->getType()));
2938     return true;
2939   }
2940   return false;
2941 }
2942 
2943 bool ModuleBitcodeWriter::pushValueOrMetadata(const Value *V, unsigned InstID,
2944                                               SmallVectorImpl<unsigned> &Vals) {
2945   bool IsMetadata = V->getType()->isMetadataTy();
2946   if (IsMetadata) {
2947     Vals.push_back(bitc::OB_METADATA);
2948     Metadata *MD = cast<MetadataAsValue>(V)->getMetadata();
2949     unsigned ValID = VE.getMetadataID(MD);
2950     Vals.push_back(InstID - ValID);
2951     return false;
2952   }
2953   return pushValueAndType(V, InstID, Vals);
2954 }
2955 
2956 void ModuleBitcodeWriter::writeOperandBundles(const CallBase &CS,
2957                                               unsigned InstID) {
2958   SmallVector<unsigned, 64> Record;
2959   LLVMContext &C = CS.getContext();
2960 
2961   for (unsigned i = 0, e = CS.getNumOperandBundles(); i != e; ++i) {
2962     const auto &Bundle = CS.getOperandBundleAt(i);
2963     Record.push_back(C.getOperandBundleTagID(Bundle.getTagName()));
2964 
2965     for (auto &Input : Bundle.Inputs)
2966       pushValueOrMetadata(Input, InstID, Record);
2967 
2968     Stream.EmitRecord(bitc::FUNC_CODE_OPERAND_BUNDLE, Record);
2969     Record.clear();
2970   }
2971 }
2972 
2973 /// pushValue - Like pushValueAndType, but where the type of the value is
2974 /// omitted (perhaps it was already encoded in an earlier operand).
2975 void ModuleBitcodeWriter::pushValue(const Value *V, unsigned InstID,
2976                                     SmallVectorImpl<unsigned> &Vals) {
2977   unsigned ValID = VE.getValueID(V);
2978   Vals.push_back(InstID - ValID);
2979 }
2980 
2981 void ModuleBitcodeWriter::pushValueSigned(const Value *V, unsigned InstID,
2982                                           SmallVectorImpl<uint64_t> &Vals) {
2983   unsigned ValID = VE.getValueID(V);
2984   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
2985   emitSignedInt64(Vals, diff);
2986 }
2987 
2988 /// WriteInstruction - Emit an instruction to the specified stream.
2989 void ModuleBitcodeWriter::writeInstruction(const Instruction &I,
2990                                            unsigned InstID,
2991                                            SmallVectorImpl<unsigned> &Vals) {
2992   unsigned Code = 0;
2993   unsigned AbbrevToUse = 0;
2994   VE.setInstructionID(&I);
2995   switch (I.getOpcode()) {
2996   default:
2997     if (Instruction::isCast(I.getOpcode())) {
2998       Code = bitc::FUNC_CODE_INST_CAST;
2999       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
3000         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
3001       Vals.push_back(VE.getTypeID(I.getType()));
3002       Vals.push_back(getEncodedCastOpcode(I.getOpcode()));
3003       uint64_t Flags = getOptimizationFlags(&I);
3004       if (Flags != 0) {
3005         if (AbbrevToUse == FUNCTION_INST_CAST_ABBREV)
3006           AbbrevToUse = FUNCTION_INST_CAST_FLAGS_ABBREV;
3007         Vals.push_back(Flags);
3008       }
3009     } else {
3010       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
3011       Code = bitc::FUNC_CODE_INST_BINOP;
3012       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
3013         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
3014       pushValue(I.getOperand(1), InstID, Vals);
3015       Vals.push_back(getEncodedBinaryOpcode(I.getOpcode()));
3016       uint64_t Flags = getOptimizationFlags(&I);
3017       if (Flags != 0) {
3018         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
3019           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
3020         Vals.push_back(Flags);
3021       }
3022     }
3023     break;
3024   case Instruction::FNeg: {
3025     Code = bitc::FUNC_CODE_INST_UNOP;
3026     if (!pushValueAndType(I.getOperand(0), InstID, Vals))
3027       AbbrevToUse = FUNCTION_INST_UNOP_ABBREV;
3028     Vals.push_back(getEncodedUnaryOpcode(I.getOpcode()));
3029     uint64_t Flags = getOptimizationFlags(&I);
3030     if (Flags != 0) {
3031       if (AbbrevToUse == FUNCTION_INST_UNOP_ABBREV)
3032         AbbrevToUse = FUNCTION_INST_UNOP_FLAGS_ABBREV;
3033       Vals.push_back(Flags);
3034     }
3035     break;
3036   }
3037   case Instruction::GetElementPtr: {
3038     Code = bitc::FUNC_CODE_INST_GEP;
3039     AbbrevToUse = FUNCTION_INST_GEP_ABBREV;
3040     auto &GEPInst = cast<GetElementPtrInst>(I);
3041     Vals.push_back(getOptimizationFlags(&I));
3042     Vals.push_back(VE.getTypeID(GEPInst.getSourceElementType()));
3043     for (const Value *Op : I.operands())
3044       pushValueAndType(Op, InstID, Vals);
3045     break;
3046   }
3047   case Instruction::ExtractValue: {
3048     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
3049     pushValueAndType(I.getOperand(0), InstID, Vals);
3050     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
3051     Vals.append(EVI->idx_begin(), EVI->idx_end());
3052     break;
3053   }
3054   case Instruction::InsertValue: {
3055     Code = bitc::FUNC_CODE_INST_INSERTVAL;
3056     pushValueAndType(I.getOperand(0), InstID, Vals);
3057     pushValueAndType(I.getOperand(1), InstID, Vals);
3058     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
3059     Vals.append(IVI->idx_begin(), IVI->idx_end());
3060     break;
3061   }
3062   case Instruction::Select: {
3063     Code = bitc::FUNC_CODE_INST_VSELECT;
3064     pushValueAndType(I.getOperand(1), InstID, Vals);
3065     pushValue(I.getOperand(2), InstID, Vals);
3066     pushValueAndType(I.getOperand(0), InstID, Vals);
3067     uint64_t Flags = getOptimizationFlags(&I);
3068     if (Flags != 0)
3069       Vals.push_back(Flags);
3070     break;
3071   }
3072   case Instruction::ExtractElement:
3073     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
3074     pushValueAndType(I.getOperand(0), InstID, Vals);
3075     pushValueAndType(I.getOperand(1), InstID, Vals);
3076     break;
3077   case Instruction::InsertElement:
3078     Code = bitc::FUNC_CODE_INST_INSERTELT;
3079     pushValueAndType(I.getOperand(0), InstID, Vals);
3080     pushValue(I.getOperand(1), InstID, Vals);
3081     pushValueAndType(I.getOperand(2), InstID, Vals);
3082     break;
3083   case Instruction::ShuffleVector:
3084     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
3085     pushValueAndType(I.getOperand(0), InstID, Vals);
3086     pushValue(I.getOperand(1), InstID, Vals);
3087     pushValue(cast<ShuffleVectorInst>(I).getShuffleMaskForBitcode(), InstID,
3088               Vals);
3089     break;
3090   case Instruction::ICmp:
3091   case Instruction::FCmp: {
3092     // compare returning Int1Ty or vector of Int1Ty
3093     Code = bitc::FUNC_CODE_INST_CMP2;
3094     pushValueAndType(I.getOperand(0), InstID, Vals);
3095     pushValue(I.getOperand(1), InstID, Vals);
3096     Vals.push_back(cast<CmpInst>(I).getPredicate());
3097     uint64_t Flags = getOptimizationFlags(&I);
3098     if (Flags != 0)
3099       Vals.push_back(Flags);
3100     break;
3101   }
3102 
3103   case Instruction::Ret:
3104     {
3105       Code = bitc::FUNC_CODE_INST_RET;
3106       unsigned NumOperands = I.getNumOperands();
3107       if (NumOperands == 0)
3108         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
3109       else if (NumOperands == 1) {
3110         if (!pushValueAndType(I.getOperand(0), InstID, Vals))
3111           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
3112       } else {
3113         for (const Value *Op : I.operands())
3114           pushValueAndType(Op, InstID, Vals);
3115       }
3116     }
3117     break;
3118   case Instruction::Br:
3119     {
3120       Code = bitc::FUNC_CODE_INST_BR;
3121       const BranchInst &II = cast<BranchInst>(I);
3122       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
3123       if (II.isConditional()) {
3124         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
3125         pushValue(II.getCondition(), InstID, Vals);
3126       }
3127     }
3128     break;
3129   case Instruction::Switch:
3130     {
3131       Code = bitc::FUNC_CODE_INST_SWITCH;
3132       const SwitchInst &SI = cast<SwitchInst>(I);
3133       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
3134       pushValue(SI.getCondition(), InstID, Vals);
3135       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
3136       for (auto Case : SI.cases()) {
3137         Vals.push_back(VE.getValueID(Case.getCaseValue()));
3138         Vals.push_back(VE.getValueID(Case.getCaseSuccessor()));
3139       }
3140     }
3141     break;
3142   case Instruction::IndirectBr:
3143     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
3144     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
3145     // Encode the address operand as relative, but not the basic blocks.
3146     pushValue(I.getOperand(0), InstID, Vals);
3147     for (const Value *Op : drop_begin(I.operands()))
3148       Vals.push_back(VE.getValueID(Op));
3149     break;
3150 
3151   case Instruction::Invoke: {
3152     const InvokeInst *II = cast<InvokeInst>(&I);
3153     const Value *Callee = II->getCalledOperand();
3154     FunctionType *FTy = II->getFunctionType();
3155 
3156     if (II->hasOperandBundles())
3157       writeOperandBundles(*II, InstID);
3158 
3159     Code = bitc::FUNC_CODE_INST_INVOKE;
3160 
3161     Vals.push_back(VE.getAttributeListID(II->getAttributes()));
3162     Vals.push_back(II->getCallingConv() | 1 << 13);
3163     Vals.push_back(VE.getValueID(II->getNormalDest()));
3164     Vals.push_back(VE.getValueID(II->getUnwindDest()));
3165     Vals.push_back(VE.getTypeID(FTy));
3166     pushValueAndType(Callee, InstID, Vals);
3167 
3168     // Emit value #'s for the fixed parameters.
3169     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
3170       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
3171 
3172     // Emit type/value pairs for varargs params.
3173     if (FTy->isVarArg()) {
3174       for (unsigned i = FTy->getNumParams(), e = II->arg_size(); i != e; ++i)
3175         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
3176     }
3177     break;
3178   }
3179   case Instruction::Resume:
3180     Code = bitc::FUNC_CODE_INST_RESUME;
3181     pushValueAndType(I.getOperand(0), InstID, Vals);
3182     break;
3183   case Instruction::CleanupRet: {
3184     Code = bitc::FUNC_CODE_INST_CLEANUPRET;
3185     const auto &CRI = cast<CleanupReturnInst>(I);
3186     pushValue(CRI.getCleanupPad(), InstID, Vals);
3187     if (CRI.hasUnwindDest())
3188       Vals.push_back(VE.getValueID(CRI.getUnwindDest()));
3189     break;
3190   }
3191   case Instruction::CatchRet: {
3192     Code = bitc::FUNC_CODE_INST_CATCHRET;
3193     const auto &CRI = cast<CatchReturnInst>(I);
3194     pushValue(CRI.getCatchPad(), InstID, Vals);
3195     Vals.push_back(VE.getValueID(CRI.getSuccessor()));
3196     break;
3197   }
3198   case Instruction::CleanupPad:
3199   case Instruction::CatchPad: {
3200     const auto &FuncletPad = cast<FuncletPadInst>(I);
3201     Code = isa<CatchPadInst>(FuncletPad) ? bitc::FUNC_CODE_INST_CATCHPAD
3202                                          : bitc::FUNC_CODE_INST_CLEANUPPAD;
3203     pushValue(FuncletPad.getParentPad(), InstID, Vals);
3204 
3205     unsigned NumArgOperands = FuncletPad.arg_size();
3206     Vals.push_back(NumArgOperands);
3207     for (unsigned Op = 0; Op != NumArgOperands; ++Op)
3208       pushValueAndType(FuncletPad.getArgOperand(Op), InstID, Vals);
3209     break;
3210   }
3211   case Instruction::CatchSwitch: {
3212     Code = bitc::FUNC_CODE_INST_CATCHSWITCH;
3213     const auto &CatchSwitch = cast<CatchSwitchInst>(I);
3214 
3215     pushValue(CatchSwitch.getParentPad(), InstID, Vals);
3216 
3217     unsigned NumHandlers = CatchSwitch.getNumHandlers();
3218     Vals.push_back(NumHandlers);
3219     for (const BasicBlock *CatchPadBB : CatchSwitch.handlers())
3220       Vals.push_back(VE.getValueID(CatchPadBB));
3221 
3222     if (CatchSwitch.hasUnwindDest())
3223       Vals.push_back(VE.getValueID(CatchSwitch.getUnwindDest()));
3224     break;
3225   }
3226   case Instruction::CallBr: {
3227     const CallBrInst *CBI = cast<CallBrInst>(&I);
3228     const Value *Callee = CBI->getCalledOperand();
3229     FunctionType *FTy = CBI->getFunctionType();
3230 
3231     if (CBI->hasOperandBundles())
3232       writeOperandBundles(*CBI, InstID);
3233 
3234     Code = bitc::FUNC_CODE_INST_CALLBR;
3235 
3236     Vals.push_back(VE.getAttributeListID(CBI->getAttributes()));
3237 
3238     Vals.push_back(CBI->getCallingConv() << bitc::CALL_CCONV |
3239                    1 << bitc::CALL_EXPLICIT_TYPE);
3240 
3241     Vals.push_back(VE.getValueID(CBI->getDefaultDest()));
3242     Vals.push_back(CBI->getNumIndirectDests());
3243     for (unsigned i = 0, e = CBI->getNumIndirectDests(); i != e; ++i)
3244       Vals.push_back(VE.getValueID(CBI->getIndirectDest(i)));
3245 
3246     Vals.push_back(VE.getTypeID(FTy));
3247     pushValueAndType(Callee, InstID, Vals);
3248 
3249     // Emit value #'s for the fixed parameters.
3250     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
3251       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
3252 
3253     // Emit type/value pairs for varargs params.
3254     if (FTy->isVarArg()) {
3255       for (unsigned i = FTy->getNumParams(), e = CBI->arg_size(); i != e; ++i)
3256         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
3257     }
3258     break;
3259   }
3260   case Instruction::Unreachable:
3261     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
3262     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
3263     break;
3264 
3265   case Instruction::PHI: {
3266     const PHINode &PN = cast<PHINode>(I);
3267     Code = bitc::FUNC_CODE_INST_PHI;
3268     // With the newer instruction encoding, forward references could give
3269     // negative valued IDs.  This is most common for PHIs, so we use
3270     // signed VBRs.
3271     SmallVector<uint64_t, 128> Vals64;
3272     Vals64.push_back(VE.getTypeID(PN.getType()));
3273     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
3274       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64);
3275       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
3276     }
3277 
3278     uint64_t Flags = getOptimizationFlags(&I);
3279     if (Flags != 0)
3280       Vals64.push_back(Flags);
3281 
3282     // Emit a Vals64 vector and exit.
3283     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
3284     Vals64.clear();
3285     return;
3286   }
3287 
3288   case Instruction::LandingPad: {
3289     const LandingPadInst &LP = cast<LandingPadInst>(I);
3290     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
3291     Vals.push_back(VE.getTypeID(LP.getType()));
3292     Vals.push_back(LP.isCleanup());
3293     Vals.push_back(LP.getNumClauses());
3294     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
3295       if (LP.isCatch(I))
3296         Vals.push_back(LandingPadInst::Catch);
3297       else
3298         Vals.push_back(LandingPadInst::Filter);
3299       pushValueAndType(LP.getClause(I), InstID, Vals);
3300     }
3301     break;
3302   }
3303 
3304   case Instruction::Alloca: {
3305     Code = bitc::FUNC_CODE_INST_ALLOCA;
3306     const AllocaInst &AI = cast<AllocaInst>(I);
3307     Vals.push_back(VE.getTypeID(AI.getAllocatedType()));
3308     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
3309     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
3310     using APV = AllocaPackedValues;
3311     unsigned Record = 0;
3312     unsigned EncodedAlign = getEncodedAlign(AI.getAlign());
3313     Bitfield::set<APV::AlignLower>(
3314         Record, EncodedAlign & ((1 << APV::AlignLower::Bits) - 1));
3315     Bitfield::set<APV::AlignUpper>(Record,
3316                                    EncodedAlign >> APV::AlignLower::Bits);
3317     Bitfield::set<APV::UsedWithInAlloca>(Record, AI.isUsedWithInAlloca());
3318     Bitfield::set<APV::ExplicitType>(Record, true);
3319     Bitfield::set<APV::SwiftError>(Record, AI.isSwiftError());
3320     Vals.push_back(Record);
3321 
3322     unsigned AS = AI.getAddressSpace();
3323     if (AS != M.getDataLayout().getAllocaAddrSpace())
3324       Vals.push_back(AS);
3325     break;
3326   }
3327 
3328   case Instruction::Load:
3329     if (cast<LoadInst>(I).isAtomic()) {
3330       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
3331       pushValueAndType(I.getOperand(0), InstID, Vals);
3332     } else {
3333       Code = bitc::FUNC_CODE_INST_LOAD;
3334       if (!pushValueAndType(I.getOperand(0), InstID, Vals)) // ptr
3335         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
3336     }
3337     Vals.push_back(VE.getTypeID(I.getType()));
3338     Vals.push_back(getEncodedAlign(cast<LoadInst>(I).getAlign()));
3339     Vals.push_back(cast<LoadInst>(I).isVolatile());
3340     if (cast<LoadInst>(I).isAtomic()) {
3341       Vals.push_back(getEncodedOrdering(cast<LoadInst>(I).getOrdering()));
3342       Vals.push_back(getEncodedSyncScopeID(cast<LoadInst>(I).getSyncScopeID()));
3343     }
3344     break;
3345   case Instruction::Store:
3346     if (cast<StoreInst>(I).isAtomic())
3347       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
3348     else
3349       Code = bitc::FUNC_CODE_INST_STORE;
3350     pushValueAndType(I.getOperand(1), InstID, Vals); // ptrty + ptr
3351     pushValueAndType(I.getOperand(0), InstID, Vals); // valty + val
3352     Vals.push_back(getEncodedAlign(cast<StoreInst>(I).getAlign()));
3353     Vals.push_back(cast<StoreInst>(I).isVolatile());
3354     if (cast<StoreInst>(I).isAtomic()) {
3355       Vals.push_back(getEncodedOrdering(cast<StoreInst>(I).getOrdering()));
3356       Vals.push_back(
3357           getEncodedSyncScopeID(cast<StoreInst>(I).getSyncScopeID()));
3358     }
3359     break;
3360   case Instruction::AtomicCmpXchg:
3361     Code = bitc::FUNC_CODE_INST_CMPXCHG;
3362     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
3363     pushValueAndType(I.getOperand(1), InstID, Vals); // cmp.
3364     pushValue(I.getOperand(2), InstID, Vals);        // newval.
3365     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
3366     Vals.push_back(
3367         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
3368     Vals.push_back(
3369         getEncodedSyncScopeID(cast<AtomicCmpXchgInst>(I).getSyncScopeID()));
3370     Vals.push_back(
3371         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
3372     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
3373     Vals.push_back(getEncodedAlign(cast<AtomicCmpXchgInst>(I).getAlign()));
3374     break;
3375   case Instruction::AtomicRMW:
3376     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
3377     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
3378     pushValueAndType(I.getOperand(1), InstID, Vals); // valty + val
3379     Vals.push_back(
3380         getEncodedRMWOperation(cast<AtomicRMWInst>(I).getOperation()));
3381     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
3382     Vals.push_back(getEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
3383     Vals.push_back(
3384         getEncodedSyncScopeID(cast<AtomicRMWInst>(I).getSyncScopeID()));
3385     Vals.push_back(getEncodedAlign(cast<AtomicRMWInst>(I).getAlign()));
3386     break;
3387   case Instruction::Fence:
3388     Code = bitc::FUNC_CODE_INST_FENCE;
3389     Vals.push_back(getEncodedOrdering(cast<FenceInst>(I).getOrdering()));
3390     Vals.push_back(getEncodedSyncScopeID(cast<FenceInst>(I).getSyncScopeID()));
3391     break;
3392   case Instruction::Call: {
3393     const CallInst &CI = cast<CallInst>(I);
3394     FunctionType *FTy = CI.getFunctionType();
3395 
3396     if (CI.hasOperandBundles())
3397       writeOperandBundles(CI, InstID);
3398 
3399     Code = bitc::FUNC_CODE_INST_CALL;
3400 
3401     Vals.push_back(VE.getAttributeListID(CI.getAttributes()));
3402 
3403     unsigned Flags = getOptimizationFlags(&I);
3404     Vals.push_back(CI.getCallingConv() << bitc::CALL_CCONV |
3405                    unsigned(CI.isTailCall()) << bitc::CALL_TAIL |
3406                    unsigned(CI.isMustTailCall()) << bitc::CALL_MUSTTAIL |
3407                    1 << bitc::CALL_EXPLICIT_TYPE |
3408                    unsigned(CI.isNoTailCall()) << bitc::CALL_NOTAIL |
3409                    unsigned(Flags != 0) << bitc::CALL_FMF);
3410     if (Flags != 0)
3411       Vals.push_back(Flags);
3412 
3413     Vals.push_back(VE.getTypeID(FTy));
3414     pushValueAndType(CI.getCalledOperand(), InstID, Vals); // Callee
3415 
3416     // Emit value #'s for the fixed parameters.
3417     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
3418       // Check for labels (can happen with asm labels).
3419       if (FTy->getParamType(i)->isLabelTy())
3420         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
3421       else
3422         pushValue(CI.getArgOperand(i), InstID, Vals); // fixed param.
3423     }
3424 
3425     // Emit type/value pairs for varargs params.
3426     if (FTy->isVarArg()) {
3427       for (unsigned i = FTy->getNumParams(), e = CI.arg_size(); i != e; ++i)
3428         pushValueAndType(CI.getArgOperand(i), InstID, Vals); // varargs
3429     }
3430     break;
3431   }
3432   case Instruction::VAArg:
3433     Code = bitc::FUNC_CODE_INST_VAARG;
3434     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
3435     pushValue(I.getOperand(0), InstID, Vals);                   // valist.
3436     Vals.push_back(VE.getTypeID(I.getType())); // restype.
3437     break;
3438   case Instruction::Freeze:
3439     Code = bitc::FUNC_CODE_INST_FREEZE;
3440     pushValueAndType(I.getOperand(0), InstID, Vals);
3441     break;
3442   }
3443 
3444   Stream.EmitRecord(Code, Vals, AbbrevToUse);
3445   Vals.clear();
3446 }
3447 
3448 /// Write a GlobalValue VST to the module. The purpose of this data structure is
3449 /// to allow clients to efficiently find the function body.
3450 void ModuleBitcodeWriter::writeGlobalValueSymbolTable(
3451   DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3452   // Get the offset of the VST we are writing, and backpatch it into
3453   // the VST forward declaration record.
3454   uint64_t VSTOffset = Stream.GetCurrentBitNo();
3455   // The BitcodeStartBit was the stream offset of the identification block.
3456   VSTOffset -= bitcodeStartBit();
3457   assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
3458   // Note that we add 1 here because the offset is relative to one word
3459   // before the start of the identification block, which was historically
3460   // always the start of the regular bitcode header.
3461   Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32 + 1);
3462 
3463   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3464 
3465   auto Abbv = std::make_shared<BitCodeAbbrev>();
3466   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
3467   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
3468   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
3469   unsigned FnEntryAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3470 
3471   for (const Function &F : M) {
3472     uint64_t Record[2];
3473 
3474     if (F.isDeclaration())
3475       continue;
3476 
3477     Record[0] = VE.getValueID(&F);
3478 
3479     // Save the word offset of the function (from the start of the
3480     // actual bitcode written to the stream).
3481     uint64_t BitcodeIndex = FunctionToBitcodeIndex[&F] - bitcodeStartBit();
3482     assert((BitcodeIndex & 31) == 0 && "function block not 32-bit aligned");
3483     // Note that we add 1 here because the offset is relative to one word
3484     // before the start of the identification block, which was historically
3485     // always the start of the regular bitcode header.
3486     Record[1] = BitcodeIndex / 32 + 1;
3487 
3488     Stream.EmitRecord(bitc::VST_CODE_FNENTRY, Record, FnEntryAbbrev);
3489   }
3490 
3491   Stream.ExitBlock();
3492 }
3493 
3494 /// Emit names for arguments, instructions and basic blocks in a function.
3495 void ModuleBitcodeWriter::writeFunctionLevelValueSymbolTable(
3496     const ValueSymbolTable &VST) {
3497   if (VST.empty())
3498     return;
3499 
3500   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3501 
3502   // FIXME: Set up the abbrev, we know how many values there are!
3503   // FIXME: We know if the type names can use 7-bit ascii.
3504   SmallVector<uint64_t, 64> NameVals;
3505 
3506   for (const ValueName &Name : VST) {
3507     // Figure out the encoding to use for the name.
3508     StringEncoding Bits = getStringEncoding(Name.getKey());
3509 
3510     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
3511     NameVals.push_back(VE.getValueID(Name.getValue()));
3512 
3513     // VST_CODE_ENTRY:   [valueid, namechar x N]
3514     // VST_CODE_BBENTRY: [bbid, namechar x N]
3515     unsigned Code;
3516     if (isa<BasicBlock>(Name.getValue())) {
3517       Code = bitc::VST_CODE_BBENTRY;
3518       if (Bits == SE_Char6)
3519         AbbrevToUse = VST_BBENTRY_6_ABBREV;
3520     } else {
3521       Code = bitc::VST_CODE_ENTRY;
3522       if (Bits == SE_Char6)
3523         AbbrevToUse = VST_ENTRY_6_ABBREV;
3524       else if (Bits == SE_Fixed7)
3525         AbbrevToUse = VST_ENTRY_7_ABBREV;
3526     }
3527 
3528     for (const auto P : Name.getKey())
3529       NameVals.push_back((unsigned char)P);
3530 
3531     // Emit the finished record.
3532     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
3533     NameVals.clear();
3534   }
3535 
3536   Stream.ExitBlock();
3537 }
3538 
3539 void ModuleBitcodeWriter::writeUseList(UseListOrder &&Order) {
3540   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
3541   unsigned Code;
3542   if (isa<BasicBlock>(Order.V))
3543     Code = bitc::USELIST_CODE_BB;
3544   else
3545     Code = bitc::USELIST_CODE_DEFAULT;
3546 
3547   SmallVector<uint64_t, 64> Record(Order.Shuffle.begin(), Order.Shuffle.end());
3548   Record.push_back(VE.getValueID(Order.V));
3549   Stream.EmitRecord(Code, Record);
3550 }
3551 
3552 void ModuleBitcodeWriter::writeUseListBlock(const Function *F) {
3553   assert(VE.shouldPreserveUseListOrder() &&
3554          "Expected to be preserving use-list order");
3555 
3556   auto hasMore = [&]() {
3557     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
3558   };
3559   if (!hasMore())
3560     // Nothing to do.
3561     return;
3562 
3563   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
3564   while (hasMore()) {
3565     writeUseList(std::move(VE.UseListOrders.back()));
3566     VE.UseListOrders.pop_back();
3567   }
3568   Stream.ExitBlock();
3569 }
3570 
3571 /// Emit a function body to the module stream.
3572 void ModuleBitcodeWriter::writeFunction(
3573     const Function &F,
3574     DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3575   // Save the bitcode index of the start of this function block for recording
3576   // in the VST.
3577   FunctionToBitcodeIndex[&F] = Stream.GetCurrentBitNo();
3578 
3579   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
3580   VE.incorporateFunction(F);
3581 
3582   SmallVector<unsigned, 64> Vals;
3583 
3584   // Emit the number of basic blocks, so the reader can create them ahead of
3585   // time.
3586   Vals.push_back(VE.getBasicBlocks().size());
3587   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
3588   Vals.clear();
3589 
3590   // If there are function-local constants, emit them now.
3591   unsigned CstStart, CstEnd;
3592   VE.getFunctionConstantRange(CstStart, CstEnd);
3593   writeConstants(CstStart, CstEnd, false);
3594 
3595   // If there is function-local metadata, emit it now.
3596   writeFunctionMetadata(F);
3597 
3598   // Keep a running idea of what the instruction ID is.
3599   unsigned InstID = CstEnd;
3600 
3601   bool NeedsMetadataAttachment = F.hasMetadata();
3602 
3603   DILocation *LastDL = nullptr;
3604   SmallSetVector<Function *, 4> BlockAddressUsers;
3605 
3606   // Finally, emit all the instructions, in order.
3607   for (const BasicBlock &BB : F) {
3608     for (const Instruction &I : BB) {
3609       writeInstruction(I, InstID, Vals);
3610 
3611       if (!I.getType()->isVoidTy())
3612         ++InstID;
3613 
3614       // If the instruction has metadata, write a metadata attachment later.
3615       NeedsMetadataAttachment |= I.hasMetadataOtherThanDebugLoc();
3616 
3617       // If the instruction has a debug location, emit it.
3618       if (DILocation *DL = I.getDebugLoc()) {
3619         if (DL == LastDL) {
3620           // Just repeat the same debug loc as last time.
3621           Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
3622         } else {
3623           Vals.push_back(DL->getLine());
3624           Vals.push_back(DL->getColumn());
3625           Vals.push_back(VE.getMetadataOrNullID(DL->getScope()));
3626           Vals.push_back(VE.getMetadataOrNullID(DL->getInlinedAt()));
3627           Vals.push_back(DL->isImplicitCode());
3628           Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
3629           Vals.clear();
3630           LastDL = DL;
3631         }
3632       }
3633 
3634       // If the instruction has DbgRecords attached to it, emit them. Note that
3635       // they come after the instruction so that it's easy to attach them again
3636       // when reading the bitcode, even though conceptually the debug locations
3637       // start "before" the instruction.
3638       if (I.hasDbgRecords() && WriteNewDbgInfoFormatToBitcode) {
3639         /// Try to push the value only (unwrapped), otherwise push the
3640         /// metadata wrapped value. Returns true if the value was pushed
3641         /// without the ValueAsMetadata wrapper.
3642         auto PushValueOrMetadata = [&Vals, InstID,
3643                                     this](Metadata *RawLocation) {
3644           assert(RawLocation &&
3645                  "RawLocation unexpectedly null in DbgVariableRecord");
3646           if (ValueAsMetadata *VAM = dyn_cast<ValueAsMetadata>(RawLocation)) {
3647             SmallVector<unsigned, 2> ValAndType;
3648             // If the value is a fwd-ref the type is also pushed. We don't
3649             // want the type, so fwd-refs are kept wrapped (pushValueAndType
3650             // returns false if the value is pushed without type).
3651             if (!pushValueAndType(VAM->getValue(), InstID, ValAndType)) {
3652               Vals.push_back(ValAndType[0]);
3653               return true;
3654             }
3655           }
3656           // The metadata is a DIArgList, or ValueAsMetadata wrapping a
3657           // fwd-ref. Push the metadata ID.
3658           Vals.push_back(VE.getMetadataID(RawLocation));
3659           return false;
3660         };
3661 
3662         // Write out non-instruction debug information attached to this
3663         // instruction. Write it after the instruction so that it's easy to
3664         // re-attach to the instruction reading the records in.
3665         for (DbgRecord &DR : I.DebugMarker->getDbgRecordRange()) {
3666           if (DbgLabelRecord *DLR = dyn_cast<DbgLabelRecord>(&DR)) {
3667             Vals.push_back(VE.getMetadataID(&*DLR->getDebugLoc()));
3668             Vals.push_back(VE.getMetadataID(DLR->getLabel()));
3669             Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_RECORD_LABEL, Vals);
3670             Vals.clear();
3671             continue;
3672           }
3673 
3674           // First 3 fields are common to all kinds:
3675           //   DILocation, DILocalVariable, DIExpression
3676           // dbg_value (FUNC_CODE_DEBUG_RECORD_VALUE)
3677           //   ..., LocationMetadata
3678           // dbg_value (FUNC_CODE_DEBUG_RECORD_VALUE_SIMPLE - abbrev'd)
3679           //   ..., Value
3680           // dbg_declare (FUNC_CODE_DEBUG_RECORD_DECLARE)
3681           //   ..., LocationMetadata
3682           // dbg_assign (FUNC_CODE_DEBUG_RECORD_ASSIGN)
3683           //   ..., LocationMetadata, DIAssignID, DIExpression, LocationMetadata
3684           DbgVariableRecord &DVR = cast<DbgVariableRecord>(DR);
3685           Vals.push_back(VE.getMetadataID(&*DVR.getDebugLoc()));
3686           Vals.push_back(VE.getMetadataID(DVR.getVariable()));
3687           Vals.push_back(VE.getMetadataID(DVR.getExpression()));
3688           if (DVR.isDbgValue()) {
3689             if (PushValueOrMetadata(DVR.getRawLocation()))
3690               Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_RECORD_VALUE_SIMPLE, Vals,
3691                                 FUNCTION_DEBUG_RECORD_VALUE_ABBREV);
3692             else
3693               Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_RECORD_VALUE, Vals);
3694           } else if (DVR.isDbgDeclare()) {
3695             Vals.push_back(VE.getMetadataID(DVR.getRawLocation()));
3696             Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_RECORD_DECLARE, Vals);
3697           } else {
3698             assert(DVR.isDbgAssign() && "Unexpected DbgRecord kind");
3699             Vals.push_back(VE.getMetadataID(DVR.getRawLocation()));
3700             Vals.push_back(VE.getMetadataID(DVR.getAssignID()));
3701             Vals.push_back(VE.getMetadataID(DVR.getAddressExpression()));
3702             Vals.push_back(VE.getMetadataID(DVR.getRawAddress()));
3703             Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_RECORD_ASSIGN, Vals);
3704           }
3705           Vals.clear();
3706         }
3707       }
3708     }
3709 
3710     if (BlockAddress *BA = BlockAddress::lookup(&BB)) {
3711       SmallVector<Value *> Worklist{BA};
3712       SmallPtrSet<Value *, 8> Visited{BA};
3713       while (!Worklist.empty()) {
3714         Value *V = Worklist.pop_back_val();
3715         for (User *U : V->users()) {
3716           if (auto *I = dyn_cast<Instruction>(U)) {
3717             Function *P = I->getFunction();
3718             if (P != &F)
3719               BlockAddressUsers.insert(P);
3720           } else if (isa<Constant>(U) && !isa<GlobalValue>(U) &&
3721                      Visited.insert(U).second)
3722             Worklist.push_back(U);
3723         }
3724       }
3725     }
3726   }
3727 
3728   if (!BlockAddressUsers.empty()) {
3729     Vals.resize(BlockAddressUsers.size());
3730     for (auto I : llvm::enumerate(BlockAddressUsers))
3731       Vals[I.index()] = VE.getValueID(I.value());
3732     Stream.EmitRecord(bitc::FUNC_CODE_BLOCKADDR_USERS, Vals);
3733     Vals.clear();
3734   }
3735 
3736   // Emit names for all the instructions etc.
3737   if (auto *Symtab = F.getValueSymbolTable())
3738     writeFunctionLevelValueSymbolTable(*Symtab);
3739 
3740   if (NeedsMetadataAttachment)
3741     writeFunctionMetadataAttachment(F);
3742   if (VE.shouldPreserveUseListOrder())
3743     writeUseListBlock(&F);
3744   VE.purgeFunction();
3745   Stream.ExitBlock();
3746 }
3747 
3748 // Emit blockinfo, which defines the standard abbreviations etc.
3749 void ModuleBitcodeWriter::writeBlockInfo() {
3750   // We only want to emit block info records for blocks that have multiple
3751   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
3752   // Other blocks can define their abbrevs inline.
3753   Stream.EnterBlockInfoBlock();
3754 
3755   { // 8-bit fixed-width VST_CODE_ENTRY/VST_CODE_BBENTRY strings.
3756     auto Abbv = std::make_shared<BitCodeAbbrev>();
3757     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
3758     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3759     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3760     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3761     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3762         VST_ENTRY_8_ABBREV)
3763       llvm_unreachable("Unexpected abbrev ordering!");
3764   }
3765 
3766   { // 7-bit fixed width VST_CODE_ENTRY strings.
3767     auto Abbv = std::make_shared<BitCodeAbbrev>();
3768     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3769     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3770     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3771     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3772     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3773         VST_ENTRY_7_ABBREV)
3774       llvm_unreachable("Unexpected abbrev ordering!");
3775   }
3776   { // 6-bit char6 VST_CODE_ENTRY strings.
3777     auto Abbv = std::make_shared<BitCodeAbbrev>();
3778     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3779     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3780     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3781     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3782     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3783         VST_ENTRY_6_ABBREV)
3784       llvm_unreachable("Unexpected abbrev ordering!");
3785   }
3786   { // 6-bit char6 VST_CODE_BBENTRY strings.
3787     auto Abbv = std::make_shared<BitCodeAbbrev>();
3788     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
3789     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3790     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3791     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3792     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3793         VST_BBENTRY_6_ABBREV)
3794       llvm_unreachable("Unexpected abbrev ordering!");
3795   }
3796 
3797   { // SETTYPE abbrev for CONSTANTS_BLOCK.
3798     auto Abbv = std::make_shared<BitCodeAbbrev>();
3799     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
3800     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
3801                               VE.computeBitsRequiredForTypeIndices()));
3802     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3803         CONSTANTS_SETTYPE_ABBREV)
3804       llvm_unreachable("Unexpected abbrev ordering!");
3805   }
3806 
3807   { // INTEGER abbrev for CONSTANTS_BLOCK.
3808     auto Abbv = std::make_shared<BitCodeAbbrev>();
3809     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
3810     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3811     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3812         CONSTANTS_INTEGER_ABBREV)
3813       llvm_unreachable("Unexpected abbrev ordering!");
3814   }
3815 
3816   { // CE_CAST abbrev for CONSTANTS_BLOCK.
3817     auto Abbv = std::make_shared<BitCodeAbbrev>();
3818     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
3819     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
3820     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
3821                               VE.computeBitsRequiredForTypeIndices()));
3822     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
3823 
3824     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3825         CONSTANTS_CE_CAST_Abbrev)
3826       llvm_unreachable("Unexpected abbrev ordering!");
3827   }
3828   { // NULL abbrev for CONSTANTS_BLOCK.
3829     auto Abbv = std::make_shared<BitCodeAbbrev>();
3830     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
3831     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3832         CONSTANTS_NULL_Abbrev)
3833       llvm_unreachable("Unexpected abbrev ordering!");
3834   }
3835 
3836   // FIXME: This should only use space for first class types!
3837 
3838   { // INST_LOAD abbrev for FUNCTION_BLOCK.
3839     auto Abbv = std::make_shared<BitCodeAbbrev>();
3840     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
3841     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
3842     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
3843                               VE.computeBitsRequiredForTypeIndices()));
3844     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
3845     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
3846     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3847         FUNCTION_INST_LOAD_ABBREV)
3848       llvm_unreachable("Unexpected abbrev ordering!");
3849   }
3850   { // INST_UNOP abbrev for FUNCTION_BLOCK.
3851     auto Abbv = std::make_shared<BitCodeAbbrev>();
3852     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3853     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3854     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3855     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3856         FUNCTION_INST_UNOP_ABBREV)
3857       llvm_unreachable("Unexpected abbrev ordering!");
3858   }
3859   { // INST_UNOP_FLAGS abbrev for FUNCTION_BLOCK.
3860     auto Abbv = std::make_shared<BitCodeAbbrev>();
3861     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3862     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3863     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3864     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3865     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3866         FUNCTION_INST_UNOP_FLAGS_ABBREV)
3867       llvm_unreachable("Unexpected abbrev ordering!");
3868   }
3869   { // INST_BINOP abbrev for FUNCTION_BLOCK.
3870     auto Abbv = std::make_shared<BitCodeAbbrev>();
3871     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3872     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3873     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3874     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3875     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3876         FUNCTION_INST_BINOP_ABBREV)
3877       llvm_unreachable("Unexpected abbrev ordering!");
3878   }
3879   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
3880     auto Abbv = std::make_shared<BitCodeAbbrev>();
3881     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3882     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3883     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3884     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3885     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3886     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3887         FUNCTION_INST_BINOP_FLAGS_ABBREV)
3888       llvm_unreachable("Unexpected abbrev ordering!");
3889   }
3890   { // INST_CAST abbrev for FUNCTION_BLOCK.
3891     auto Abbv = std::make_shared<BitCodeAbbrev>();
3892     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
3893     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
3894     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
3895                               VE.computeBitsRequiredForTypeIndices()));
3896     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
3897     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3898         FUNCTION_INST_CAST_ABBREV)
3899       llvm_unreachable("Unexpected abbrev ordering!");
3900   }
3901   { // INST_CAST_FLAGS abbrev for FUNCTION_BLOCK.
3902     auto Abbv = std::make_shared<BitCodeAbbrev>();
3903     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
3904     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // OpVal
3905     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
3906                               VE.computeBitsRequiredForTypeIndices()));
3907     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3908     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3909     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3910         FUNCTION_INST_CAST_FLAGS_ABBREV)
3911       llvm_unreachable("Unexpected abbrev ordering!");
3912   }
3913 
3914   { // INST_RET abbrev for FUNCTION_BLOCK.
3915     auto Abbv = std::make_shared<BitCodeAbbrev>();
3916     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3917     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3918         FUNCTION_INST_RET_VOID_ABBREV)
3919       llvm_unreachable("Unexpected abbrev ordering!");
3920   }
3921   { // INST_RET abbrev for FUNCTION_BLOCK.
3922     auto Abbv = std::make_shared<BitCodeAbbrev>();
3923     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3924     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
3925     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3926         FUNCTION_INST_RET_VAL_ABBREV)
3927       llvm_unreachable("Unexpected abbrev ordering!");
3928   }
3929   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
3930     auto Abbv = std::make_shared<BitCodeAbbrev>();
3931     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
3932     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3933         FUNCTION_INST_UNREACHABLE_ABBREV)
3934       llvm_unreachable("Unexpected abbrev ordering!");
3935   }
3936   {
3937     auto Abbv = std::make_shared<BitCodeAbbrev>();
3938     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_GEP));
3939     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
3940     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, // dest ty
3941                               Log2_32_Ceil(VE.getTypes().size() + 1)));
3942     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3943     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
3944     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3945         FUNCTION_INST_GEP_ABBREV)
3946       llvm_unreachable("Unexpected abbrev ordering!");
3947   }
3948   {
3949     auto Abbv = std::make_shared<BitCodeAbbrev>();
3950     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_DEBUG_RECORD_VALUE_SIMPLE));
3951     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 7)); // dbgloc
3952     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 7)); // var
3953     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 7)); // expr
3954     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // val
3955     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3956         FUNCTION_DEBUG_RECORD_VALUE_ABBREV)
3957       llvm_unreachable("Unexpected abbrev ordering! 1");
3958   }
3959   Stream.ExitBlock();
3960 }
3961 
3962 /// Write the module path strings, currently only used when generating
3963 /// a combined index file.
3964 void IndexBitcodeWriter::writeModStrings() {
3965   Stream.EnterSubblock(bitc::MODULE_STRTAB_BLOCK_ID, 3);
3966 
3967   // TODO: See which abbrev sizes we actually need to emit
3968 
3969   // 8-bit fixed-width MST_ENTRY strings.
3970   auto Abbv = std::make_shared<BitCodeAbbrev>();
3971   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3972   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3973   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3974   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3975   unsigned Abbrev8Bit = Stream.EmitAbbrev(std::move(Abbv));
3976 
3977   // 7-bit fixed width MST_ENTRY strings.
3978   Abbv = std::make_shared<BitCodeAbbrev>();
3979   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3980   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3981   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3982   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3983   unsigned Abbrev7Bit = Stream.EmitAbbrev(std::move(Abbv));
3984 
3985   // 6-bit char6 MST_ENTRY strings.
3986   Abbv = std::make_shared<BitCodeAbbrev>();
3987   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3988   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3989   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3990   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3991   unsigned Abbrev6Bit = Stream.EmitAbbrev(std::move(Abbv));
3992 
3993   // Module Hash, 160 bits SHA1. Optionally, emitted after each MST_CODE_ENTRY.
3994   Abbv = std::make_shared<BitCodeAbbrev>();
3995   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_HASH));
3996   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3997   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3998   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3999   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
4000   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
4001   unsigned AbbrevHash = Stream.EmitAbbrev(std::move(Abbv));
4002 
4003   SmallVector<unsigned, 64> Vals;
4004   forEachModule([&](const StringMapEntry<ModuleHash> &MPSE) {
4005     StringRef Key = MPSE.getKey();
4006     const auto &Hash = MPSE.getValue();
4007     StringEncoding Bits = getStringEncoding(Key);
4008     unsigned AbbrevToUse = Abbrev8Bit;
4009     if (Bits == SE_Char6)
4010       AbbrevToUse = Abbrev6Bit;
4011     else if (Bits == SE_Fixed7)
4012       AbbrevToUse = Abbrev7Bit;
4013 
4014     auto ModuleId = ModuleIdMap.size();
4015     ModuleIdMap[Key] = ModuleId;
4016     Vals.push_back(ModuleId);
4017     Vals.append(Key.begin(), Key.end());
4018 
4019     // Emit the finished record.
4020     Stream.EmitRecord(bitc::MST_CODE_ENTRY, Vals, AbbrevToUse);
4021 
4022     // Emit an optional hash for the module now
4023     if (llvm::any_of(Hash, [](uint32_t H) { return H; })) {
4024       Vals.assign(Hash.begin(), Hash.end());
4025       // Emit the hash record.
4026       Stream.EmitRecord(bitc::MST_CODE_HASH, Vals, AbbrevHash);
4027     }
4028 
4029     Vals.clear();
4030   });
4031   Stream.ExitBlock();
4032 }
4033 
4034 /// Write the function type metadata related records that need to appear before
4035 /// a function summary entry (whether per-module or combined).
4036 template <typename Fn>
4037 static void writeFunctionTypeMetadataRecords(BitstreamWriter &Stream,
4038                                              FunctionSummary *FS,
4039                                              Fn GetValueID) {
4040   if (!FS->type_tests().empty())
4041     Stream.EmitRecord(bitc::FS_TYPE_TESTS, FS->type_tests());
4042 
4043   SmallVector<uint64_t, 64> Record;
4044 
4045   auto WriteVFuncIdVec = [&](uint64_t Ty,
4046                              ArrayRef<FunctionSummary::VFuncId> VFs) {
4047     if (VFs.empty())
4048       return;
4049     Record.clear();
4050     for (auto &VF : VFs) {
4051       Record.push_back(VF.GUID);
4052       Record.push_back(VF.Offset);
4053     }
4054     Stream.EmitRecord(Ty, Record);
4055   };
4056 
4057   WriteVFuncIdVec(bitc::FS_TYPE_TEST_ASSUME_VCALLS,
4058                   FS->type_test_assume_vcalls());
4059   WriteVFuncIdVec(bitc::FS_TYPE_CHECKED_LOAD_VCALLS,
4060                   FS->type_checked_load_vcalls());
4061 
4062   auto WriteConstVCallVec = [&](uint64_t Ty,
4063                                 ArrayRef<FunctionSummary::ConstVCall> VCs) {
4064     for (auto &VC : VCs) {
4065       Record.clear();
4066       Record.push_back(VC.VFunc.GUID);
4067       Record.push_back(VC.VFunc.Offset);
4068       llvm::append_range(Record, VC.Args);
4069       Stream.EmitRecord(Ty, Record);
4070     }
4071   };
4072 
4073   WriteConstVCallVec(bitc::FS_TYPE_TEST_ASSUME_CONST_VCALL,
4074                      FS->type_test_assume_const_vcalls());
4075   WriteConstVCallVec(bitc::FS_TYPE_CHECKED_LOAD_CONST_VCALL,
4076                      FS->type_checked_load_const_vcalls());
4077 
4078   auto WriteRange = [&](ConstantRange Range) {
4079     Range = Range.sextOrTrunc(FunctionSummary::ParamAccess::RangeWidth);
4080     assert(Range.getLower().getNumWords() == 1);
4081     assert(Range.getUpper().getNumWords() == 1);
4082     emitSignedInt64(Record, *Range.getLower().getRawData());
4083     emitSignedInt64(Record, *Range.getUpper().getRawData());
4084   };
4085 
4086   if (!FS->paramAccesses().empty()) {
4087     Record.clear();
4088     for (auto &Arg : FS->paramAccesses()) {
4089       size_t UndoSize = Record.size();
4090       Record.push_back(Arg.ParamNo);
4091       WriteRange(Arg.Use);
4092       Record.push_back(Arg.Calls.size());
4093       for (auto &Call : Arg.Calls) {
4094         Record.push_back(Call.ParamNo);
4095         std::optional<unsigned> ValueID = GetValueID(Call.Callee);
4096         if (!ValueID) {
4097           // If ValueID is unknown we can't drop just this call, we must drop
4098           // entire parameter.
4099           Record.resize(UndoSize);
4100           break;
4101         }
4102         Record.push_back(*ValueID);
4103         WriteRange(Call.Offsets);
4104       }
4105     }
4106     if (!Record.empty())
4107       Stream.EmitRecord(bitc::FS_PARAM_ACCESS, Record);
4108   }
4109 }
4110 
4111 /// Collect type IDs from type tests used by function.
4112 static void
4113 getReferencedTypeIds(FunctionSummary *FS,
4114                      std::set<GlobalValue::GUID> &ReferencedTypeIds) {
4115   if (!FS->type_tests().empty())
4116     for (auto &TT : FS->type_tests())
4117       ReferencedTypeIds.insert(TT);
4118 
4119   auto GetReferencedTypesFromVFuncIdVec =
4120       [&](ArrayRef<FunctionSummary::VFuncId> VFs) {
4121         for (auto &VF : VFs)
4122           ReferencedTypeIds.insert(VF.GUID);
4123       };
4124 
4125   GetReferencedTypesFromVFuncIdVec(FS->type_test_assume_vcalls());
4126   GetReferencedTypesFromVFuncIdVec(FS->type_checked_load_vcalls());
4127 
4128   auto GetReferencedTypesFromConstVCallVec =
4129       [&](ArrayRef<FunctionSummary::ConstVCall> VCs) {
4130         for (auto &VC : VCs)
4131           ReferencedTypeIds.insert(VC.VFunc.GUID);
4132       };
4133 
4134   GetReferencedTypesFromConstVCallVec(FS->type_test_assume_const_vcalls());
4135   GetReferencedTypesFromConstVCallVec(FS->type_checked_load_const_vcalls());
4136 }
4137 
4138 static void writeWholeProgramDevirtResolutionByArg(
4139     SmallVector<uint64_t, 64> &NameVals, const std::vector<uint64_t> &args,
4140     const WholeProgramDevirtResolution::ByArg &ByArg) {
4141   NameVals.push_back(args.size());
4142   llvm::append_range(NameVals, args);
4143 
4144   NameVals.push_back(ByArg.TheKind);
4145   NameVals.push_back(ByArg.Info);
4146   NameVals.push_back(ByArg.Byte);
4147   NameVals.push_back(ByArg.Bit);
4148 }
4149 
4150 static void writeWholeProgramDevirtResolution(
4151     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
4152     uint64_t Id, const WholeProgramDevirtResolution &Wpd) {
4153   NameVals.push_back(Id);
4154 
4155   NameVals.push_back(Wpd.TheKind);
4156   NameVals.push_back(StrtabBuilder.add(Wpd.SingleImplName));
4157   NameVals.push_back(Wpd.SingleImplName.size());
4158 
4159   NameVals.push_back(Wpd.ResByArg.size());
4160   for (auto &A : Wpd.ResByArg)
4161     writeWholeProgramDevirtResolutionByArg(NameVals, A.first, A.second);
4162 }
4163 
4164 static void writeTypeIdSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
4165                                      StringTableBuilder &StrtabBuilder,
4166                                      const std::string &Id,
4167                                      const TypeIdSummary &Summary) {
4168   NameVals.push_back(StrtabBuilder.add(Id));
4169   NameVals.push_back(Id.size());
4170 
4171   NameVals.push_back(Summary.TTRes.TheKind);
4172   NameVals.push_back(Summary.TTRes.SizeM1BitWidth);
4173   NameVals.push_back(Summary.TTRes.AlignLog2);
4174   NameVals.push_back(Summary.TTRes.SizeM1);
4175   NameVals.push_back(Summary.TTRes.BitMask);
4176   NameVals.push_back(Summary.TTRes.InlineBits);
4177 
4178   for (auto &W : Summary.WPDRes)
4179     writeWholeProgramDevirtResolution(NameVals, StrtabBuilder, W.first,
4180                                       W.second);
4181 }
4182 
4183 static void writeTypeIdCompatibleVtableSummaryRecord(
4184     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
4185     const std::string &Id, const TypeIdCompatibleVtableInfo &Summary,
4186     ValueEnumerator &VE) {
4187   NameVals.push_back(StrtabBuilder.add(Id));
4188   NameVals.push_back(Id.size());
4189 
4190   for (auto &P : Summary) {
4191     NameVals.push_back(P.AddressPointOffset);
4192     NameVals.push_back(VE.getValueID(P.VTableVI.getValue()));
4193   }
4194 }
4195 
4196 static void writeFunctionHeapProfileRecords(
4197     BitstreamWriter &Stream, FunctionSummary *FS, unsigned CallsiteAbbrev,
4198     unsigned AllocAbbrev, bool PerModule,
4199     std::function<unsigned(const ValueInfo &VI)> GetValueID,
4200     std::function<unsigned(unsigned)> GetStackIndex) {
4201   SmallVector<uint64_t> Record;
4202 
4203   for (auto &CI : FS->callsites()) {
4204     Record.clear();
4205     // Per module callsite clones should always have a single entry of
4206     // value 0.
4207     assert(!PerModule || (CI.Clones.size() == 1 && CI.Clones[0] == 0));
4208     Record.push_back(GetValueID(CI.Callee));
4209     if (!PerModule) {
4210       Record.push_back(CI.StackIdIndices.size());
4211       Record.push_back(CI.Clones.size());
4212     }
4213     for (auto Id : CI.StackIdIndices)
4214       Record.push_back(GetStackIndex(Id));
4215     if (!PerModule) {
4216       for (auto V : CI.Clones)
4217         Record.push_back(V);
4218     }
4219     Stream.EmitRecord(PerModule ? bitc::FS_PERMODULE_CALLSITE_INFO
4220                                 : bitc::FS_COMBINED_CALLSITE_INFO,
4221                       Record, CallsiteAbbrev);
4222   }
4223 
4224   for (auto &AI : FS->allocs()) {
4225     Record.clear();
4226     // Per module alloc versions should always have a single entry of
4227     // value 0.
4228     assert(!PerModule || (AI.Versions.size() == 1 && AI.Versions[0] == 0));
4229     Record.push_back(AI.MIBs.size());
4230     if (!PerModule)
4231       Record.push_back(AI.Versions.size());
4232     for (auto &MIB : AI.MIBs) {
4233       Record.push_back((uint8_t)MIB.AllocType);
4234       Record.push_back(MIB.StackIdIndices.size());
4235       for (auto Id : MIB.StackIdIndices)
4236         Record.push_back(GetStackIndex(Id));
4237     }
4238     if (!PerModule) {
4239       for (auto V : AI.Versions)
4240         Record.push_back(V);
4241     }
4242     assert(AI.TotalSizes.empty() || AI.TotalSizes.size() == AI.MIBs.size());
4243     if (!AI.TotalSizes.empty()) {
4244       for (auto Size : AI.TotalSizes)
4245         Record.push_back(Size);
4246     }
4247     Stream.EmitRecord(PerModule ? bitc::FS_PERMODULE_ALLOC_INFO
4248                                 : bitc::FS_COMBINED_ALLOC_INFO,
4249                       Record, AllocAbbrev);
4250   }
4251 }
4252 
4253 // Helper to emit a single function summary record.
4254 void ModuleBitcodeWriterBase::writePerModuleFunctionSummaryRecord(
4255     SmallVector<uint64_t, 64> &NameVals, GlobalValueSummary *Summary,
4256     unsigned ValueID, unsigned FSCallsRelBFAbbrev,
4257     unsigned FSCallsProfileAbbrev, unsigned CallsiteAbbrev,
4258     unsigned AllocAbbrev, const Function &F) {
4259   NameVals.push_back(ValueID);
4260 
4261   FunctionSummary *FS = cast<FunctionSummary>(Summary);
4262 
4263   writeFunctionTypeMetadataRecords(
4264       Stream, FS, [&](const ValueInfo &VI) -> std::optional<unsigned> {
4265         return {VE.getValueID(VI.getValue())};
4266       });
4267 
4268   writeFunctionHeapProfileRecords(
4269       Stream, FS, CallsiteAbbrev, AllocAbbrev,
4270       /*PerModule*/ true,
4271       /*GetValueId*/ [&](const ValueInfo &VI) { return getValueId(VI); },
4272       /*GetStackIndex*/ [&](unsigned I) { return I; });
4273 
4274   auto SpecialRefCnts = FS->specialRefCounts();
4275   NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
4276   NameVals.push_back(FS->instCount());
4277   NameVals.push_back(getEncodedFFlags(FS->fflags()));
4278   NameVals.push_back(FS->refs().size());
4279   NameVals.push_back(SpecialRefCnts.first);  // rorefcnt
4280   NameVals.push_back(SpecialRefCnts.second); // worefcnt
4281 
4282   for (auto &RI : FS->refs())
4283     NameVals.push_back(getValueId(RI));
4284 
4285   const bool UseRelBFRecord =
4286       WriteRelBFToSummary && !F.hasProfileData() &&
4287       ForceSummaryEdgesCold == FunctionSummary::FSHT_None;
4288   for (auto &ECI : FS->calls()) {
4289     NameVals.push_back(getValueId(ECI.first));
4290     if (UseRelBFRecord)
4291       NameVals.push_back(getEncodedRelBFCallEdgeInfo(ECI.second));
4292     else
4293       NameVals.push_back(getEncodedHotnessCallEdgeInfo(ECI.second));
4294   }
4295 
4296   unsigned FSAbbrev =
4297       (UseRelBFRecord ? FSCallsRelBFAbbrev : FSCallsProfileAbbrev);
4298   unsigned Code =
4299       (UseRelBFRecord ? bitc::FS_PERMODULE_RELBF : bitc::FS_PERMODULE_PROFILE);
4300 
4301   // Emit the finished record.
4302   Stream.EmitRecord(Code, NameVals, FSAbbrev);
4303   NameVals.clear();
4304 }
4305 
4306 // Collect the global value references in the given variable's initializer,
4307 // and emit them in a summary record.
4308 void ModuleBitcodeWriterBase::writeModuleLevelReferences(
4309     const GlobalVariable &V, SmallVector<uint64_t, 64> &NameVals,
4310     unsigned FSModRefsAbbrev, unsigned FSModVTableRefsAbbrev) {
4311   auto VI = Index->getValueInfo(V.getGUID());
4312   if (!VI || VI.getSummaryList().empty()) {
4313     // Only declarations should not have a summary (a declaration might however
4314     // have a summary if the def was in module level asm).
4315     assert(V.isDeclaration());
4316     return;
4317   }
4318   auto *Summary = VI.getSummaryList()[0].get();
4319   NameVals.push_back(VE.getValueID(&V));
4320   GlobalVarSummary *VS = cast<GlobalVarSummary>(Summary);
4321   NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
4322   NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
4323 
4324   auto VTableFuncs = VS->vTableFuncs();
4325   if (!VTableFuncs.empty())
4326     NameVals.push_back(VS->refs().size());
4327 
4328   unsigned SizeBeforeRefs = NameVals.size();
4329   for (auto &RI : VS->refs())
4330     NameVals.push_back(VE.getValueID(RI.getValue()));
4331   // Sort the refs for determinism output, the vector returned by FS->refs() has
4332   // been initialized from a DenseSet.
4333   llvm::sort(drop_begin(NameVals, SizeBeforeRefs));
4334 
4335   if (VTableFuncs.empty())
4336     Stream.EmitRecord(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS, NameVals,
4337                       FSModRefsAbbrev);
4338   else {
4339     // VTableFuncs pairs should already be sorted by offset.
4340     for (auto &P : VTableFuncs) {
4341       NameVals.push_back(VE.getValueID(P.FuncVI.getValue()));
4342       NameVals.push_back(P.VTableOffset);
4343     }
4344 
4345     Stream.EmitRecord(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS, NameVals,
4346                       FSModVTableRefsAbbrev);
4347   }
4348   NameVals.clear();
4349 }
4350 
4351 /// Emit the per-module summary section alongside the rest of
4352 /// the module's bitcode.
4353 void ModuleBitcodeWriterBase::writePerModuleGlobalValueSummary() {
4354   // By default we compile with ThinLTO if the module has a summary, but the
4355   // client can request full LTO with a module flag.
4356   bool IsThinLTO = true;
4357   if (auto *MD =
4358           mdconst::extract_or_null<ConstantInt>(M.getModuleFlag("ThinLTO")))
4359     IsThinLTO = MD->getZExtValue();
4360   Stream.EnterSubblock(IsThinLTO ? bitc::GLOBALVAL_SUMMARY_BLOCK_ID
4361                                  : bitc::FULL_LTO_GLOBALVAL_SUMMARY_BLOCK_ID,
4362                        4);
4363 
4364   Stream.EmitRecord(
4365       bitc::FS_VERSION,
4366       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
4367 
4368   // Write the index flags.
4369   uint64_t Flags = 0;
4370   // Bits 1-3 are set only in the combined index, skip them.
4371   if (Index->enableSplitLTOUnit())
4372     Flags |= 0x8;
4373   if (Index->hasUnifiedLTO())
4374     Flags |= 0x200;
4375 
4376   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Flags});
4377 
4378   if (Index->begin() == Index->end()) {
4379     Stream.ExitBlock();
4380     return;
4381   }
4382 
4383   auto Abbv = std::make_shared<BitCodeAbbrev>();
4384   Abbv->Add(BitCodeAbbrevOp(bitc::FS_VALUE_GUID));
4385   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
4386   // GUIDS often use up most of 64-bits, so encode as two Fixed 32.
4387   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
4388   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
4389   unsigned ValueGuidAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4390 
4391   for (const auto &GVI : valueIds()) {
4392     Stream.EmitRecord(bitc::FS_VALUE_GUID,
4393                       ArrayRef<uint32_t>{GVI.second,
4394                                          static_cast<uint32_t>(GVI.first >> 32),
4395                                          static_cast<uint32_t>(GVI.first)},
4396                       ValueGuidAbbrev);
4397   }
4398 
4399   if (!Index->stackIds().empty()) {
4400     auto StackIdAbbv = std::make_shared<BitCodeAbbrev>();
4401     StackIdAbbv->Add(BitCodeAbbrevOp(bitc::FS_STACK_IDS));
4402     // numids x stackid
4403     StackIdAbbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4404     StackIdAbbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4405     unsigned StackIdAbbvId = Stream.EmitAbbrev(std::move(StackIdAbbv));
4406     Stream.EmitRecord(bitc::FS_STACK_IDS, Index->stackIds(), StackIdAbbvId);
4407   }
4408 
4409   // Abbrev for FS_PERMODULE_PROFILE.
4410   Abbv = std::make_shared<BitCodeAbbrev>();
4411   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_PROFILE));
4412   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4413   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // flags
4414   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4415   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4416   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4417   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4418   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4419   // numrefs x valueid, n x (valueid, hotness+tailcall flags)
4420   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4421   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4422   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4423 
4424   // Abbrev for FS_PERMODULE_RELBF.
4425   Abbv = std::make_shared<BitCodeAbbrev>();
4426   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_RELBF));
4427   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4428   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4429   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4430   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4431   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4432   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4433   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4434   // numrefs x valueid, n x (valueid, rel_block_freq+tailcall])
4435   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4436   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4437   unsigned FSCallsRelBFAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4438 
4439   // Abbrev for FS_PERMODULE_GLOBALVAR_INIT_REFS.
4440   Abbv = std::make_shared<BitCodeAbbrev>();
4441   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS));
4442   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
4443   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
4444   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));  // valueids
4445   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4446   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4447 
4448   // Abbrev for FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS.
4449   Abbv = std::make_shared<BitCodeAbbrev>();
4450   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS));
4451   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
4452   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
4453   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numrefs
4454   // numrefs x valueid, n x (valueid , offset)
4455   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4456   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4457   unsigned FSModVTableRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4458 
4459   // Abbrev for FS_ALIAS.
4460   Abbv = std::make_shared<BitCodeAbbrev>();
4461   Abbv->Add(BitCodeAbbrevOp(bitc::FS_ALIAS));
4462   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4463   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4464   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4465   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4466 
4467   // Abbrev for FS_TYPE_ID_METADATA
4468   Abbv = std::make_shared<BitCodeAbbrev>();
4469   Abbv->Add(BitCodeAbbrevOp(bitc::FS_TYPE_ID_METADATA));
4470   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid strtab index
4471   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid length
4472   // n x (valueid , offset)
4473   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4474   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4475   unsigned TypeIdCompatibleVtableAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4476 
4477   Abbv = std::make_shared<BitCodeAbbrev>();
4478   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_CALLSITE_INFO));
4479   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
4480   // n x stackidindex
4481   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4482   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4483   unsigned CallsiteAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4484 
4485   Abbv = std::make_shared<BitCodeAbbrev>();
4486   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_ALLOC_INFO));
4487   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // nummib
4488   // n x (alloc type, numstackids, numstackids x stackidindex)
4489   // optional: nummib x total size
4490   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4491   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4492   unsigned AllocAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4493 
4494   SmallVector<uint64_t, 64> NameVals;
4495   // Iterate over the list of functions instead of the Index to
4496   // ensure the ordering is stable.
4497   for (const Function &F : M) {
4498     // Summary emission does not support anonymous functions, they have to
4499     // renamed using the anonymous function renaming pass.
4500     if (!F.hasName())
4501       report_fatal_error("Unexpected anonymous function when writing summary");
4502 
4503     ValueInfo VI = Index->getValueInfo(F.getGUID());
4504     if (!VI || VI.getSummaryList().empty()) {
4505       // Only declarations should not have a summary (a declaration might
4506       // however have a summary if the def was in module level asm).
4507       assert(F.isDeclaration());
4508       continue;
4509     }
4510     auto *Summary = VI.getSummaryList()[0].get();
4511     writePerModuleFunctionSummaryRecord(
4512         NameVals, Summary, VE.getValueID(&F), FSCallsRelBFAbbrev,
4513         FSCallsProfileAbbrev, CallsiteAbbrev, AllocAbbrev, F);
4514   }
4515 
4516   // Capture references from GlobalVariable initializers, which are outside
4517   // of a function scope.
4518   for (const GlobalVariable &G : M.globals())
4519     writeModuleLevelReferences(G, NameVals, FSModRefsAbbrev,
4520                                FSModVTableRefsAbbrev);
4521 
4522   for (const GlobalAlias &A : M.aliases()) {
4523     auto *Aliasee = A.getAliaseeObject();
4524     // Skip ifunc and nameless functions which don't have an entry in the
4525     // summary.
4526     if (!Aliasee->hasName() || isa<GlobalIFunc>(Aliasee))
4527       continue;
4528     auto AliasId = VE.getValueID(&A);
4529     auto AliaseeId = VE.getValueID(Aliasee);
4530     NameVals.push_back(AliasId);
4531     auto *Summary = Index->getGlobalValueSummary(A);
4532     AliasSummary *AS = cast<AliasSummary>(Summary);
4533     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
4534     NameVals.push_back(AliaseeId);
4535     Stream.EmitRecord(bitc::FS_ALIAS, NameVals, FSAliasAbbrev);
4536     NameVals.clear();
4537   }
4538 
4539   for (auto &S : Index->typeIdCompatibleVtableMap()) {
4540     writeTypeIdCompatibleVtableSummaryRecord(NameVals, StrtabBuilder, S.first,
4541                                              S.second, VE);
4542     Stream.EmitRecord(bitc::FS_TYPE_ID_METADATA, NameVals,
4543                       TypeIdCompatibleVtableAbbrev);
4544     NameVals.clear();
4545   }
4546 
4547   if (Index->getBlockCount())
4548     Stream.EmitRecord(bitc::FS_BLOCK_COUNT,
4549                       ArrayRef<uint64_t>{Index->getBlockCount()});
4550 
4551   Stream.ExitBlock();
4552 }
4553 
4554 /// Emit the combined summary section into the combined index file.
4555 void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
4556   Stream.EnterSubblock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID, 4);
4557   Stream.EmitRecord(
4558       bitc::FS_VERSION,
4559       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
4560 
4561   // Write the index flags.
4562   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Index.getFlags()});
4563 
4564   auto Abbv = std::make_shared<BitCodeAbbrev>();
4565   Abbv->Add(BitCodeAbbrevOp(bitc::FS_VALUE_GUID));
4566   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
4567   // GUIDS often use up most of 64-bits, so encode as two Fixed 32.
4568   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
4569   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
4570   unsigned ValueGuidAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4571 
4572   for (const auto &GVI : valueIds()) {
4573     Stream.EmitRecord(bitc::FS_VALUE_GUID,
4574                       ArrayRef<uint32_t>{GVI.second,
4575                                          static_cast<uint32_t>(GVI.first >> 32),
4576                                          static_cast<uint32_t>(GVI.first)},
4577                       ValueGuidAbbrev);
4578   }
4579 
4580   // Write the stack ids used by this index, which will be a subset of those in
4581   // the full index in the case of distributed indexes.
4582   if (!StackIds.empty()) {
4583     auto StackIdAbbv = std::make_shared<BitCodeAbbrev>();
4584     StackIdAbbv->Add(BitCodeAbbrevOp(bitc::FS_STACK_IDS));
4585     // numids x stackid
4586     StackIdAbbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4587     StackIdAbbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4588     unsigned StackIdAbbvId = Stream.EmitAbbrev(std::move(StackIdAbbv));
4589     Stream.EmitRecord(bitc::FS_STACK_IDS, StackIds, StackIdAbbvId);
4590   }
4591 
4592   // Abbrev for FS_COMBINED_PROFILE.
4593   Abbv = std::make_shared<BitCodeAbbrev>();
4594   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_PROFILE));
4595   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4596   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4597   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4598   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4599   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4600   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
4601   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4602   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4603   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4604   // numrefs x valueid, n x (valueid, hotness+tailcall flags)
4605   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4606   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4607   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4608 
4609   // Abbrev for FS_COMBINED_GLOBALVAR_INIT_REFS.
4610   Abbv = std::make_shared<BitCodeAbbrev>();
4611   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS));
4612   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4613   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4614   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4615   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));    // valueids
4616   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4617   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4618 
4619   // Abbrev for FS_COMBINED_ALIAS.
4620   Abbv = std::make_shared<BitCodeAbbrev>();
4621   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_ALIAS));
4622   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4623   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4624   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4625   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4626   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4627 
4628   Abbv = std::make_shared<BitCodeAbbrev>();
4629   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_CALLSITE_INFO));
4630   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
4631   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numstackindices
4632   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numver
4633   // numstackindices x stackidindex, numver x version
4634   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4635   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4636   unsigned CallsiteAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4637 
4638   Abbv = std::make_shared<BitCodeAbbrev>();
4639   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_ALLOC_INFO));
4640   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // nummib
4641   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numver
4642   // nummib x (alloc type, numstackids, numstackids x stackidindex),
4643   // numver x version
4644   // optional: nummib x total size
4645   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4646   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4647   unsigned AllocAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4648 
4649   auto shouldImportValueAsDecl = [&](GlobalValueSummary *GVS) -> bool {
4650     if (DecSummaries == nullptr)
4651       return false;
4652     return DecSummaries->count(GVS);
4653   };
4654 
4655   // The aliases are emitted as a post-pass, and will point to the value
4656   // id of the aliasee. Save them in a vector for post-processing.
4657   SmallVector<AliasSummary *, 64> Aliases;
4658 
4659   // Save the value id for each summary for alias emission.
4660   DenseMap<const GlobalValueSummary *, unsigned> SummaryToValueIdMap;
4661 
4662   SmallVector<uint64_t, 64> NameVals;
4663 
4664   // Set that will be populated during call to writeFunctionTypeMetadataRecords
4665   // with the type ids referenced by this index file.
4666   std::set<GlobalValue::GUID> ReferencedTypeIds;
4667 
4668   // For local linkage, we also emit the original name separately
4669   // immediately after the record.
4670   auto MaybeEmitOriginalName = [&](GlobalValueSummary &S) {
4671     // We don't need to emit the original name if we are writing the index for
4672     // distributed backends (in which case ModuleToSummariesForIndex is
4673     // non-null). The original name is only needed during the thin link, since
4674     // for SamplePGO the indirect call targets for local functions have
4675     // have the original name annotated in profile.
4676     // Continue to emit it when writing out the entire combined index, which is
4677     // used in testing the thin link via llvm-lto.
4678     if (ModuleToSummariesForIndex || !GlobalValue::isLocalLinkage(S.linkage()))
4679       return;
4680     NameVals.push_back(S.getOriginalName());
4681     Stream.EmitRecord(bitc::FS_COMBINED_ORIGINAL_NAME, NameVals);
4682     NameVals.clear();
4683   };
4684 
4685   DenseSet<GlobalValue::GUID> DefOrUseGUIDs;
4686   forEachSummary([&](GVInfo I, bool IsAliasee) {
4687     GlobalValueSummary *S = I.second;
4688     assert(S);
4689     DefOrUseGUIDs.insert(I.first);
4690     for (const ValueInfo &VI : S->refs())
4691       DefOrUseGUIDs.insert(VI.getGUID());
4692 
4693     auto ValueId = getValueId(I.first);
4694     assert(ValueId);
4695     SummaryToValueIdMap[S] = *ValueId;
4696 
4697     // If this is invoked for an aliasee, we want to record the above
4698     // mapping, but then not emit a summary entry (if the aliasee is
4699     // to be imported, we will invoke this separately with IsAliasee=false).
4700     if (IsAliasee)
4701       return;
4702 
4703     if (auto *AS = dyn_cast<AliasSummary>(S)) {
4704       // Will process aliases as a post-pass because the reader wants all
4705       // global to be loaded first.
4706       Aliases.push_back(AS);
4707       return;
4708     }
4709 
4710     if (auto *VS = dyn_cast<GlobalVarSummary>(S)) {
4711       NameVals.push_back(*ValueId);
4712       assert(ModuleIdMap.count(VS->modulePath()));
4713       NameVals.push_back(ModuleIdMap[VS->modulePath()]);
4714       NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
4715       NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
4716       for (auto &RI : VS->refs()) {
4717         auto RefValueId = getValueId(RI.getGUID());
4718         if (!RefValueId)
4719           continue;
4720         NameVals.push_back(*RefValueId);
4721       }
4722 
4723       // Emit the finished record.
4724       Stream.EmitRecord(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS, NameVals,
4725                         FSModRefsAbbrev);
4726       NameVals.clear();
4727       MaybeEmitOriginalName(*S);
4728       return;
4729     }
4730 
4731     auto GetValueId = [&](const ValueInfo &VI) -> std::optional<unsigned> {
4732       if (!VI)
4733         return std::nullopt;
4734       return getValueId(VI.getGUID());
4735     };
4736 
4737     auto *FS = cast<FunctionSummary>(S);
4738     writeFunctionTypeMetadataRecords(Stream, FS, GetValueId);
4739     getReferencedTypeIds(FS, ReferencedTypeIds);
4740 
4741     writeFunctionHeapProfileRecords(
4742         Stream, FS, CallsiteAbbrev, AllocAbbrev,
4743         /*PerModule*/ false,
4744         /*GetValueId*/
4745         [&](const ValueInfo &VI) -> unsigned {
4746           std::optional<unsigned> ValueID = GetValueId(VI);
4747           // This can happen in shared index files for distributed ThinLTO if
4748           // the callee function summary is not included. Record 0 which we
4749           // will have to deal with conservatively when doing any kind of
4750           // validation in the ThinLTO backends.
4751           if (!ValueID)
4752             return 0;
4753           return *ValueID;
4754         },
4755         /*GetStackIndex*/
4756         [&](unsigned I) {
4757           // Get the corresponding index into the list of StackIds actually
4758           // being written for this combined index (which may be a subset in
4759           // the case of distributed indexes).
4760           assert(StackIdIndicesToIndex.contains(I));
4761           return StackIdIndicesToIndex[I];
4762         });
4763 
4764     NameVals.push_back(*ValueId);
4765     assert(ModuleIdMap.count(FS->modulePath()));
4766     NameVals.push_back(ModuleIdMap[FS->modulePath()]);
4767     NameVals.push_back(
4768         getEncodedGVSummaryFlags(FS->flags(), shouldImportValueAsDecl(FS)));
4769     NameVals.push_back(FS->instCount());
4770     NameVals.push_back(getEncodedFFlags(FS->fflags()));
4771     // TODO: Stop writing entry count and bump bitcode version.
4772     NameVals.push_back(0 /* EntryCount */);
4773 
4774     // Fill in below
4775     NameVals.push_back(0); // numrefs
4776     NameVals.push_back(0); // rorefcnt
4777     NameVals.push_back(0); // worefcnt
4778 
4779     unsigned Count = 0, RORefCnt = 0, WORefCnt = 0;
4780     for (auto &RI : FS->refs()) {
4781       auto RefValueId = getValueId(RI.getGUID());
4782       if (!RefValueId)
4783         continue;
4784       NameVals.push_back(*RefValueId);
4785       if (RI.isReadOnly())
4786         RORefCnt++;
4787       else if (RI.isWriteOnly())
4788         WORefCnt++;
4789       Count++;
4790     }
4791     NameVals[6] = Count;
4792     NameVals[7] = RORefCnt;
4793     NameVals[8] = WORefCnt;
4794 
4795     for (auto &EI : FS->calls()) {
4796       // If this GUID doesn't have a value id, it doesn't have a function
4797       // summary and we don't need to record any calls to it.
4798       std::optional<unsigned> CallValueId = GetValueId(EI.first);
4799       if (!CallValueId)
4800         continue;
4801       NameVals.push_back(*CallValueId);
4802       NameVals.push_back(getEncodedHotnessCallEdgeInfo(EI.second));
4803     }
4804 
4805     // Emit the finished record.
4806     Stream.EmitRecord(bitc::FS_COMBINED_PROFILE, NameVals,
4807                       FSCallsProfileAbbrev);
4808     NameVals.clear();
4809     MaybeEmitOriginalName(*S);
4810   });
4811 
4812   for (auto *AS : Aliases) {
4813     auto AliasValueId = SummaryToValueIdMap[AS];
4814     assert(AliasValueId);
4815     NameVals.push_back(AliasValueId);
4816     assert(ModuleIdMap.count(AS->modulePath()));
4817     NameVals.push_back(ModuleIdMap[AS->modulePath()]);
4818     NameVals.push_back(
4819         getEncodedGVSummaryFlags(AS->flags(), shouldImportValueAsDecl(AS)));
4820     auto AliaseeValueId = SummaryToValueIdMap[&AS->getAliasee()];
4821     assert(AliaseeValueId);
4822     NameVals.push_back(AliaseeValueId);
4823 
4824     // Emit the finished record.
4825     Stream.EmitRecord(bitc::FS_COMBINED_ALIAS, NameVals, FSAliasAbbrev);
4826     NameVals.clear();
4827     MaybeEmitOriginalName(*AS);
4828 
4829     if (auto *FS = dyn_cast<FunctionSummary>(&AS->getAliasee()))
4830       getReferencedTypeIds(FS, ReferencedTypeIds);
4831   }
4832 
4833   if (!Index.cfiFunctionDefs().empty()) {
4834     for (auto &S : Index.cfiFunctionDefs()) {
4835       if (DefOrUseGUIDs.contains(
4836               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4837         NameVals.push_back(StrtabBuilder.add(S));
4838         NameVals.push_back(S.size());
4839       }
4840     }
4841     if (!NameVals.empty()) {
4842       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DEFS, NameVals);
4843       NameVals.clear();
4844     }
4845   }
4846 
4847   if (!Index.cfiFunctionDecls().empty()) {
4848     for (auto &S : Index.cfiFunctionDecls()) {
4849       if (DefOrUseGUIDs.contains(
4850               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4851         NameVals.push_back(StrtabBuilder.add(S));
4852         NameVals.push_back(S.size());
4853       }
4854     }
4855     if (!NameVals.empty()) {
4856       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DECLS, NameVals);
4857       NameVals.clear();
4858     }
4859   }
4860 
4861   // Walk the GUIDs that were referenced, and write the
4862   // corresponding type id records.
4863   for (auto &T : ReferencedTypeIds) {
4864     auto TidIter = Index.typeIds().equal_range(T);
4865     for (const auto &[GUID, TypeIdPair] : make_range(TidIter)) {
4866       writeTypeIdSummaryRecord(NameVals, StrtabBuilder, TypeIdPair.first,
4867                                TypeIdPair.second);
4868       Stream.EmitRecord(bitc::FS_TYPE_ID, NameVals);
4869       NameVals.clear();
4870     }
4871   }
4872 
4873   if (Index.getBlockCount())
4874     Stream.EmitRecord(bitc::FS_BLOCK_COUNT,
4875                       ArrayRef<uint64_t>{Index.getBlockCount()});
4876 
4877   Stream.ExitBlock();
4878 }
4879 
4880 /// Create the "IDENTIFICATION_BLOCK_ID" containing a single string with the
4881 /// current llvm version, and a record for the epoch number.
4882 static void writeIdentificationBlock(BitstreamWriter &Stream) {
4883   Stream.EnterSubblock(bitc::IDENTIFICATION_BLOCK_ID, 5);
4884 
4885   // Write the "user readable" string identifying the bitcode producer
4886   auto Abbv = std::make_shared<BitCodeAbbrev>();
4887   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_STRING));
4888   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4889   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
4890   auto StringAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4891   writeStringRecord(Stream, bitc::IDENTIFICATION_CODE_STRING,
4892                     "LLVM" LLVM_VERSION_STRING, StringAbbrev);
4893 
4894   // Write the epoch version
4895   Abbv = std::make_shared<BitCodeAbbrev>();
4896   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_EPOCH));
4897   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
4898   auto EpochAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4899   constexpr std::array<unsigned, 1> Vals = {{bitc::BITCODE_CURRENT_EPOCH}};
4900   Stream.EmitRecord(bitc::IDENTIFICATION_CODE_EPOCH, Vals, EpochAbbrev);
4901   Stream.ExitBlock();
4902 }
4903 
4904 void ModuleBitcodeWriter::writeModuleHash(StringRef View) {
4905   // Emit the module's hash.
4906   // MODULE_CODE_HASH: [5*i32]
4907   if (GenerateHash) {
4908     uint32_t Vals[5];
4909     Hasher.update(ArrayRef<uint8_t>(
4910         reinterpret_cast<const uint8_t *>(View.data()), View.size()));
4911     std::array<uint8_t, 20> Hash = Hasher.result();
4912     for (int Pos = 0; Pos < 20; Pos += 4) {
4913       Vals[Pos / 4] = support::endian::read32be(Hash.data() + Pos);
4914     }
4915 
4916     // Emit the finished record.
4917     Stream.EmitRecord(bitc::MODULE_CODE_HASH, Vals);
4918 
4919     if (ModHash)
4920       // Save the written hash value.
4921       llvm::copy(Vals, std::begin(*ModHash));
4922   }
4923 }
4924 
4925 void ModuleBitcodeWriter::write() {
4926   writeIdentificationBlock(Stream);
4927 
4928   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4929   // We will want to write the module hash at this point. Block any flushing so
4930   // we can have access to the whole underlying data later.
4931   Stream.markAndBlockFlushing();
4932 
4933   writeModuleVersion();
4934 
4935   // Emit blockinfo, which defines the standard abbreviations etc.
4936   writeBlockInfo();
4937 
4938   // Emit information describing all of the types in the module.
4939   writeTypeTable();
4940 
4941   // Emit information about attribute groups.
4942   writeAttributeGroupTable();
4943 
4944   // Emit information about parameter attributes.
4945   writeAttributeTable();
4946 
4947   writeComdats();
4948 
4949   // Emit top-level description of module, including target triple, inline asm,
4950   // descriptors for global variables, and function prototype info.
4951   writeModuleInfo();
4952 
4953   // Emit constants.
4954   writeModuleConstants();
4955 
4956   // Emit metadata kind names.
4957   writeModuleMetadataKinds();
4958 
4959   // Emit metadata.
4960   writeModuleMetadata();
4961 
4962   // Emit module-level use-lists.
4963   if (VE.shouldPreserveUseListOrder())
4964     writeUseListBlock(nullptr);
4965 
4966   writeOperandBundleTags();
4967   writeSyncScopeNames();
4968 
4969   // Emit function bodies.
4970   DenseMap<const Function *, uint64_t> FunctionToBitcodeIndex;
4971   for (const Function &F : M)
4972     if (!F.isDeclaration())
4973       writeFunction(F, FunctionToBitcodeIndex);
4974 
4975   // Need to write after the above call to WriteFunction which populates
4976   // the summary information in the index.
4977   if (Index)
4978     writePerModuleGlobalValueSummary();
4979 
4980   writeGlobalValueSymbolTable(FunctionToBitcodeIndex);
4981 
4982   writeModuleHash(Stream.getMarkedBufferAndResumeFlushing());
4983 
4984   Stream.ExitBlock();
4985 }
4986 
4987 static void writeInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
4988                                uint32_t &Position) {
4989   support::endian::write32le(&Buffer[Position], Value);
4990   Position += 4;
4991 }
4992 
4993 /// If generating a bc file on darwin, we have to emit a
4994 /// header and trailer to make it compatible with the system archiver.  To do
4995 /// this we emit the following header, and then emit a trailer that pads the
4996 /// file out to be a multiple of 16 bytes.
4997 ///
4998 /// struct bc_header {
4999 ///   uint32_t Magic;         // 0x0B17C0DE
5000 ///   uint32_t Version;       // Version, currently always 0.
5001 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
5002 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
5003 ///   uint32_t CPUType;       // CPU specifier.
5004 ///   ... potentially more later ...
5005 /// };
5006 static void emitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
5007                                          const Triple &TT) {
5008   unsigned CPUType = ~0U;
5009 
5010   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
5011   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
5012   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
5013   // specific constants here because they are implicitly part of the Darwin ABI.
5014   enum {
5015     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
5016     DARWIN_CPU_TYPE_X86        = 7,
5017     DARWIN_CPU_TYPE_ARM        = 12,
5018     DARWIN_CPU_TYPE_POWERPC    = 18
5019   };
5020 
5021   Triple::ArchType Arch = TT.getArch();
5022   if (Arch == Triple::x86_64)
5023     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
5024   else if (Arch == Triple::x86)
5025     CPUType = DARWIN_CPU_TYPE_X86;
5026   else if (Arch == Triple::ppc)
5027     CPUType = DARWIN_CPU_TYPE_POWERPC;
5028   else if (Arch == Triple::ppc64)
5029     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
5030   else if (Arch == Triple::arm || Arch == Triple::thumb)
5031     CPUType = DARWIN_CPU_TYPE_ARM;
5032 
5033   // Traditional Bitcode starts after header.
5034   assert(Buffer.size() >= BWH_HeaderSize &&
5035          "Expected header size to be reserved");
5036   unsigned BCOffset = BWH_HeaderSize;
5037   unsigned BCSize = Buffer.size() - BWH_HeaderSize;
5038 
5039   // Write the magic and version.
5040   unsigned Position = 0;
5041   writeInt32ToBuffer(0x0B17C0DE, Buffer, Position);
5042   writeInt32ToBuffer(0, Buffer, Position); // Version.
5043   writeInt32ToBuffer(BCOffset, Buffer, Position);
5044   writeInt32ToBuffer(BCSize, Buffer, Position);
5045   writeInt32ToBuffer(CPUType, Buffer, Position);
5046 
5047   // If the file is not a multiple of 16 bytes, insert dummy padding.
5048   while (Buffer.size() & 15)
5049     Buffer.push_back(0);
5050 }
5051 
5052 /// Helper to write the header common to all bitcode files.
5053 static void writeBitcodeHeader(BitstreamWriter &Stream) {
5054   // Emit the file header.
5055   Stream.Emit((unsigned)'B', 8);
5056   Stream.Emit((unsigned)'C', 8);
5057   Stream.Emit(0x0, 4);
5058   Stream.Emit(0xC, 4);
5059   Stream.Emit(0xE, 4);
5060   Stream.Emit(0xD, 4);
5061 }
5062 
5063 BitcodeWriter::BitcodeWriter(SmallVectorImpl<char> &Buffer)
5064     : Stream(new BitstreamWriter(Buffer)) {
5065   writeBitcodeHeader(*Stream);
5066 }
5067 
5068 BitcodeWriter::BitcodeWriter(raw_ostream &FS)
5069     : Stream(new BitstreamWriter(FS, FlushThreshold)) {
5070   writeBitcodeHeader(*Stream);
5071 }
5072 
5073 BitcodeWriter::~BitcodeWriter() { assert(WroteStrtab); }
5074 
5075 void BitcodeWriter::writeBlob(unsigned Block, unsigned Record, StringRef Blob) {
5076   Stream->EnterSubblock(Block, 3);
5077 
5078   auto Abbv = std::make_shared<BitCodeAbbrev>();
5079   Abbv->Add(BitCodeAbbrevOp(Record));
5080   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
5081   auto AbbrevNo = Stream->EmitAbbrev(std::move(Abbv));
5082 
5083   Stream->EmitRecordWithBlob(AbbrevNo, ArrayRef<uint64_t>{Record}, Blob);
5084 
5085   Stream->ExitBlock();
5086 }
5087 
5088 void BitcodeWriter::writeSymtab() {
5089   assert(!WroteStrtab && !WroteSymtab);
5090 
5091   // If any module has module-level inline asm, we will require a registered asm
5092   // parser for the target so that we can create an accurate symbol table for
5093   // the module.
5094   for (Module *M : Mods) {
5095     if (M->getModuleInlineAsm().empty())
5096       continue;
5097 
5098     std::string Err;
5099     const Triple TT(M->getTargetTriple());
5100     const Target *T = TargetRegistry::lookupTarget(TT.str(), Err);
5101     if (!T || !T->hasMCAsmParser())
5102       return;
5103   }
5104 
5105   WroteSymtab = true;
5106   SmallVector<char, 0> Symtab;
5107   // The irsymtab::build function may be unable to create a symbol table if the
5108   // module is malformed (e.g. it contains an invalid alias). Writing a symbol
5109   // table is not required for correctness, but we still want to be able to
5110   // write malformed modules to bitcode files, so swallow the error.
5111   if (Error E = irsymtab::build(Mods, Symtab, StrtabBuilder, Alloc)) {
5112     consumeError(std::move(E));
5113     return;
5114   }
5115 
5116   writeBlob(bitc::SYMTAB_BLOCK_ID, bitc::SYMTAB_BLOB,
5117             {Symtab.data(), Symtab.size()});
5118 }
5119 
5120 void BitcodeWriter::writeStrtab() {
5121   assert(!WroteStrtab);
5122 
5123   std::vector<char> Strtab;
5124   StrtabBuilder.finalizeInOrder();
5125   Strtab.resize(StrtabBuilder.getSize());
5126   StrtabBuilder.write((uint8_t *)Strtab.data());
5127 
5128   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB,
5129             {Strtab.data(), Strtab.size()});
5130 
5131   WroteStrtab = true;
5132 }
5133 
5134 void BitcodeWriter::copyStrtab(StringRef Strtab) {
5135   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB, Strtab);
5136   WroteStrtab = true;
5137 }
5138 
5139 void BitcodeWriter::writeModule(const Module &M,
5140                                 bool ShouldPreserveUseListOrder,
5141                                 const ModuleSummaryIndex *Index,
5142                                 bool GenerateHash, ModuleHash *ModHash) {
5143   assert(!WroteStrtab);
5144 
5145   // The Mods vector is used by irsymtab::build, which requires non-const
5146   // Modules in case it needs to materialize metadata. But the bitcode writer
5147   // requires that the module is materialized, so we can cast to non-const here,
5148   // after checking that it is in fact materialized.
5149   assert(M.isMaterialized());
5150   Mods.push_back(const_cast<Module *>(&M));
5151 
5152   ModuleBitcodeWriter ModuleWriter(M, StrtabBuilder, *Stream,
5153                                    ShouldPreserveUseListOrder, Index,
5154                                    GenerateHash, ModHash);
5155   ModuleWriter.write();
5156 }
5157 
5158 void BitcodeWriter::writeIndex(
5159     const ModuleSummaryIndex *Index,
5160     const ModuleToSummariesForIndexTy *ModuleToSummariesForIndex,
5161     const GVSummaryPtrSet *DecSummaries) {
5162   IndexBitcodeWriter IndexWriter(*Stream, StrtabBuilder, *Index, DecSummaries,
5163                                  ModuleToSummariesForIndex);
5164   IndexWriter.write();
5165 }
5166 
5167 /// Write the specified module to the specified output stream.
5168 void llvm::WriteBitcodeToFile(const Module &M, raw_ostream &Out,
5169                               bool ShouldPreserveUseListOrder,
5170                               const ModuleSummaryIndex *Index,
5171                               bool GenerateHash, ModuleHash *ModHash) {
5172   auto Write = [&](BitcodeWriter &Writer) {
5173     Writer.writeModule(M, ShouldPreserveUseListOrder, Index, GenerateHash,
5174                        ModHash);
5175     Writer.writeSymtab();
5176     Writer.writeStrtab();
5177   };
5178   Triple TT(M.getTargetTriple());
5179   if (TT.isOSDarwin() || TT.isOSBinFormatMachO()) {
5180     // If this is darwin or another generic macho target, reserve space for the
5181     // header. Note that the header is computed *after* the output is known, so
5182     // we currently explicitly use a buffer, write to it, and then subsequently
5183     // flush to Out.
5184     SmallVector<char, 0> Buffer;
5185     Buffer.reserve(256 * 1024);
5186     Buffer.insert(Buffer.begin(), BWH_HeaderSize, 0);
5187     BitcodeWriter Writer(Buffer);
5188     Write(Writer);
5189     emitDarwinBCHeaderAndTrailer(Buffer, TT);
5190     Out.write(Buffer.data(), Buffer.size());
5191   } else {
5192     BitcodeWriter Writer(Out);
5193     Write(Writer);
5194   }
5195 }
5196 
5197 void IndexBitcodeWriter::write() {
5198   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
5199 
5200   writeModuleVersion();
5201 
5202   // Write the module paths in the combined index.
5203   writeModStrings();
5204 
5205   // Write the summary combined index records.
5206   writeCombinedGlobalValueSummary();
5207 
5208   Stream.ExitBlock();
5209 }
5210 
5211 // Write the specified module summary index to the given raw output stream,
5212 // where it will be written in a new bitcode block. This is used when
5213 // writing the combined index file for ThinLTO. When writing a subset of the
5214 // index for a distributed backend, provide a \p ModuleToSummariesForIndex map.
5215 void llvm::writeIndexToFile(
5216     const ModuleSummaryIndex &Index, raw_ostream &Out,
5217     const ModuleToSummariesForIndexTy *ModuleToSummariesForIndex,
5218     const GVSummaryPtrSet *DecSummaries) {
5219   SmallVector<char, 0> Buffer;
5220   Buffer.reserve(256 * 1024);
5221 
5222   BitcodeWriter Writer(Buffer);
5223   Writer.writeIndex(&Index, ModuleToSummariesForIndex, DecSummaries);
5224   Writer.writeStrtab();
5225 
5226   Out.write((char *)&Buffer.front(), Buffer.size());
5227 }
5228 
5229 namespace {
5230 
5231 /// Class to manage the bitcode writing for a thin link bitcode file.
5232 class ThinLinkBitcodeWriter : public ModuleBitcodeWriterBase {
5233   /// ModHash is for use in ThinLTO incremental build, generated while writing
5234   /// the module bitcode file.
5235   const ModuleHash *ModHash;
5236 
5237 public:
5238   ThinLinkBitcodeWriter(const Module &M, StringTableBuilder &StrtabBuilder,
5239                         BitstreamWriter &Stream,
5240                         const ModuleSummaryIndex &Index,
5241                         const ModuleHash &ModHash)
5242       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
5243                                 /*ShouldPreserveUseListOrder=*/false, &Index),
5244         ModHash(&ModHash) {}
5245 
5246   void write();
5247 
5248 private:
5249   void writeSimplifiedModuleInfo();
5250 };
5251 
5252 } // end anonymous namespace
5253 
5254 // This function writes a simpilified module info for thin link bitcode file.
5255 // It only contains the source file name along with the name(the offset and
5256 // size in strtab) and linkage for global values. For the global value info
5257 // entry, in order to keep linkage at offset 5, there are three zeros used
5258 // as padding.
5259 void ThinLinkBitcodeWriter::writeSimplifiedModuleInfo() {
5260   SmallVector<unsigned, 64> Vals;
5261   // Emit the module's source file name.
5262   {
5263     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
5264     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
5265     if (Bits == SE_Char6)
5266       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
5267     else if (Bits == SE_Fixed7)
5268       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
5269 
5270     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
5271     auto Abbv = std::make_shared<BitCodeAbbrev>();
5272     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
5273     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
5274     Abbv->Add(AbbrevOpToUse);
5275     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
5276 
5277     for (const auto P : M.getSourceFileName())
5278       Vals.push_back((unsigned char)P);
5279 
5280     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
5281     Vals.clear();
5282   }
5283 
5284   // Emit the global variable information.
5285   for (const GlobalVariable &GV : M.globals()) {
5286     // GLOBALVAR: [strtab offset, strtab size, 0, 0, 0, linkage]
5287     Vals.push_back(StrtabBuilder.add(GV.getName()));
5288     Vals.push_back(GV.getName().size());
5289     Vals.push_back(0);
5290     Vals.push_back(0);
5291     Vals.push_back(0);
5292     Vals.push_back(getEncodedLinkage(GV));
5293 
5294     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals);
5295     Vals.clear();
5296   }
5297 
5298   // Emit the function proto information.
5299   for (const Function &F : M) {
5300     // FUNCTION:  [strtab offset, strtab size, 0, 0, 0, linkage]
5301     Vals.push_back(StrtabBuilder.add(F.getName()));
5302     Vals.push_back(F.getName().size());
5303     Vals.push_back(0);
5304     Vals.push_back(0);
5305     Vals.push_back(0);
5306     Vals.push_back(getEncodedLinkage(F));
5307 
5308     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals);
5309     Vals.clear();
5310   }
5311 
5312   // Emit the alias information.
5313   for (const GlobalAlias &A : M.aliases()) {
5314     // ALIAS: [strtab offset, strtab size, 0, 0, 0, linkage]
5315     Vals.push_back(StrtabBuilder.add(A.getName()));
5316     Vals.push_back(A.getName().size());
5317     Vals.push_back(0);
5318     Vals.push_back(0);
5319     Vals.push_back(0);
5320     Vals.push_back(getEncodedLinkage(A));
5321 
5322     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals);
5323     Vals.clear();
5324   }
5325 
5326   // Emit the ifunc information.
5327   for (const GlobalIFunc &I : M.ifuncs()) {
5328     // IFUNC: [strtab offset, strtab size, 0, 0, 0, linkage]
5329     Vals.push_back(StrtabBuilder.add(I.getName()));
5330     Vals.push_back(I.getName().size());
5331     Vals.push_back(0);
5332     Vals.push_back(0);
5333     Vals.push_back(0);
5334     Vals.push_back(getEncodedLinkage(I));
5335 
5336     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
5337     Vals.clear();
5338   }
5339 }
5340 
5341 void ThinLinkBitcodeWriter::write() {
5342   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
5343 
5344   writeModuleVersion();
5345 
5346   writeSimplifiedModuleInfo();
5347 
5348   writePerModuleGlobalValueSummary();
5349 
5350   // Write module hash.
5351   Stream.EmitRecord(bitc::MODULE_CODE_HASH, ArrayRef<uint32_t>(*ModHash));
5352 
5353   Stream.ExitBlock();
5354 }
5355 
5356 void BitcodeWriter::writeThinLinkBitcode(const Module &M,
5357                                          const ModuleSummaryIndex &Index,
5358                                          const ModuleHash &ModHash) {
5359   assert(!WroteStrtab);
5360 
5361   // The Mods vector is used by irsymtab::build, which requires non-const
5362   // Modules in case it needs to materialize metadata. But the bitcode writer
5363   // requires that the module is materialized, so we can cast to non-const here,
5364   // after checking that it is in fact materialized.
5365   assert(M.isMaterialized());
5366   Mods.push_back(const_cast<Module *>(&M));
5367 
5368   ThinLinkBitcodeWriter ThinLinkWriter(M, StrtabBuilder, *Stream, Index,
5369                                        ModHash);
5370   ThinLinkWriter.write();
5371 }
5372 
5373 // Write the specified thin link bitcode file to the given raw output stream,
5374 // where it will be written in a new bitcode block. This is used when
5375 // writing the per-module index file for ThinLTO.
5376 void llvm::writeThinLinkBitcodeToFile(const Module &M, raw_ostream &Out,
5377                                       const ModuleSummaryIndex &Index,
5378                                       const ModuleHash &ModHash) {
5379   SmallVector<char, 0> Buffer;
5380   Buffer.reserve(256 * 1024);
5381 
5382   BitcodeWriter Writer(Buffer);
5383   Writer.writeThinLinkBitcode(M, Index, ModHash);
5384   Writer.writeSymtab();
5385   Writer.writeStrtab();
5386 
5387   Out.write((char *)&Buffer.front(), Buffer.size());
5388 }
5389 
5390 static const char *getSectionNameForBitcode(const Triple &T) {
5391   switch (T.getObjectFormat()) {
5392   case Triple::MachO:
5393     return "__LLVM,__bitcode";
5394   case Triple::COFF:
5395   case Triple::ELF:
5396   case Triple::Wasm:
5397   case Triple::UnknownObjectFormat:
5398     return ".llvmbc";
5399   case Triple::GOFF:
5400     llvm_unreachable("GOFF is not yet implemented");
5401     break;
5402   case Triple::SPIRV:
5403     if (T.getVendor() == Triple::AMD)
5404       return ".llvmbc";
5405     llvm_unreachable("SPIRV is not yet implemented");
5406     break;
5407   case Triple::XCOFF:
5408     llvm_unreachable("XCOFF is not yet implemented");
5409     break;
5410   case Triple::DXContainer:
5411     llvm_unreachable("DXContainer is not yet implemented");
5412     break;
5413   }
5414   llvm_unreachable("Unimplemented ObjectFormatType");
5415 }
5416 
5417 static const char *getSectionNameForCommandline(const Triple &T) {
5418   switch (T.getObjectFormat()) {
5419   case Triple::MachO:
5420     return "__LLVM,__cmdline";
5421   case Triple::COFF:
5422   case Triple::ELF:
5423   case Triple::Wasm:
5424   case Triple::UnknownObjectFormat:
5425     return ".llvmcmd";
5426   case Triple::GOFF:
5427     llvm_unreachable("GOFF is not yet implemented");
5428     break;
5429   case Triple::SPIRV:
5430     if (T.getVendor() == Triple::AMD)
5431       return ".llvmcmd";
5432     llvm_unreachable("SPIRV is not yet implemented");
5433     break;
5434   case Triple::XCOFF:
5435     llvm_unreachable("XCOFF is not yet implemented");
5436     break;
5437   case Triple::DXContainer:
5438     llvm_unreachable("DXC is not yet implemented");
5439     break;
5440   }
5441   llvm_unreachable("Unimplemented ObjectFormatType");
5442 }
5443 
5444 void llvm::embedBitcodeInModule(llvm::Module &M, llvm::MemoryBufferRef Buf,
5445                                 bool EmbedBitcode, bool EmbedCmdline,
5446                                 const std::vector<uint8_t> &CmdArgs) {
5447   // Save llvm.compiler.used and remove it.
5448   SmallVector<Constant *, 2> UsedArray;
5449   SmallVector<GlobalValue *, 4> UsedGlobals;
5450   Type *UsedElementType = PointerType::getUnqual(M.getContext());
5451   GlobalVariable *Used = collectUsedGlobalVariables(M, UsedGlobals, true);
5452   for (auto *GV : UsedGlobals) {
5453     if (GV->getName() != "llvm.embedded.module" &&
5454         GV->getName() != "llvm.cmdline")
5455       UsedArray.push_back(
5456           ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
5457   }
5458   if (Used)
5459     Used->eraseFromParent();
5460 
5461   // Embed the bitcode for the llvm module.
5462   std::string Data;
5463   ArrayRef<uint8_t> ModuleData;
5464   Triple T(M.getTargetTriple());
5465 
5466   if (EmbedBitcode) {
5467     if (Buf.getBufferSize() == 0 ||
5468         !isBitcode((const unsigned char *)Buf.getBufferStart(),
5469                    (const unsigned char *)Buf.getBufferEnd())) {
5470       // If the input is LLVM Assembly, bitcode is produced by serializing
5471       // the module. Use-lists order need to be preserved in this case.
5472       llvm::raw_string_ostream OS(Data);
5473       llvm::WriteBitcodeToFile(M, OS, /* ShouldPreserveUseListOrder */ true);
5474       ModuleData =
5475           ArrayRef<uint8_t>((const uint8_t *)OS.str().data(), OS.str().size());
5476     } else
5477       // If the input is LLVM bitcode, write the input byte stream directly.
5478       ModuleData = ArrayRef<uint8_t>((const uint8_t *)Buf.getBufferStart(),
5479                                      Buf.getBufferSize());
5480   }
5481   llvm::Constant *ModuleConstant =
5482       llvm::ConstantDataArray::get(M.getContext(), ModuleData);
5483   llvm::GlobalVariable *GV = new llvm::GlobalVariable(
5484       M, ModuleConstant->getType(), true, llvm::GlobalValue::PrivateLinkage,
5485       ModuleConstant);
5486   GV->setSection(getSectionNameForBitcode(T));
5487   // Set alignment to 1 to prevent padding between two contributions from input
5488   // sections after linking.
5489   GV->setAlignment(Align(1));
5490   UsedArray.push_back(
5491       ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
5492   if (llvm::GlobalVariable *Old =
5493           M.getGlobalVariable("llvm.embedded.module", true)) {
5494     assert(Old->hasZeroLiveUses() &&
5495            "llvm.embedded.module can only be used once in llvm.compiler.used");
5496     GV->takeName(Old);
5497     Old->eraseFromParent();
5498   } else {
5499     GV->setName("llvm.embedded.module");
5500   }
5501 
5502   // Skip if only bitcode needs to be embedded.
5503   if (EmbedCmdline) {
5504     // Embed command-line options.
5505     ArrayRef<uint8_t> CmdData(const_cast<uint8_t *>(CmdArgs.data()),
5506                               CmdArgs.size());
5507     llvm::Constant *CmdConstant =
5508         llvm::ConstantDataArray::get(M.getContext(), CmdData);
5509     GV = new llvm::GlobalVariable(M, CmdConstant->getType(), true,
5510                                   llvm::GlobalValue::PrivateLinkage,
5511                                   CmdConstant);
5512     GV->setSection(getSectionNameForCommandline(T));
5513     GV->setAlignment(Align(1));
5514     UsedArray.push_back(
5515         ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
5516     if (llvm::GlobalVariable *Old = M.getGlobalVariable("llvm.cmdline", true)) {
5517       assert(Old->hasZeroLiveUses() &&
5518              "llvm.cmdline can only be used once in llvm.compiler.used");
5519       GV->takeName(Old);
5520       Old->eraseFromParent();
5521     } else {
5522       GV->setName("llvm.cmdline");
5523     }
5524   }
5525 
5526   if (UsedArray.empty())
5527     return;
5528 
5529   // Recreate llvm.compiler.used.
5530   ArrayType *ATy = ArrayType::get(UsedElementType, UsedArray.size());
5531   auto *NewUsed = new GlobalVariable(
5532       M, ATy, false, llvm::GlobalValue::AppendingLinkage,
5533       llvm::ConstantArray::get(ATy, UsedArray), "llvm.compiler.used");
5534   NewUsed->setSection("llvm.metadata");
5535 }
5536