xref: /llvm-project/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp (revision 14120227a34365e829d05c1413033d235d7d272c)
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   void writeOperandBundles(const CallBase &CB, unsigned InstID);
399   void pushValue(const Value *V, unsigned InstID,
400                  SmallVectorImpl<unsigned> &Vals);
401   void pushValueSigned(const Value *V, unsigned InstID,
402                        SmallVectorImpl<uint64_t> &Vals);
403   void writeInstruction(const Instruction &I, unsigned InstID,
404                         SmallVectorImpl<unsigned> &Vals);
405   void writeFunctionLevelValueSymbolTable(const ValueSymbolTable &VST);
406   void writeGlobalValueSymbolTable(
407       DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
408   void writeUseList(UseListOrder &&Order);
409   void writeUseListBlock(const Function *F);
410   void
411   writeFunction(const Function &F,
412                 DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
413   void writeBlockInfo();
414   void writeModuleHash(StringRef View);
415 
416   unsigned getEncodedSyncScopeID(SyncScope::ID SSID) {
417     return unsigned(SSID);
418   }
419 
420   unsigned getEncodedAlign(MaybeAlign Alignment) { return encode(Alignment); }
421 };
422 
423 /// Class to manage the bitcode writing for a combined index.
424 class IndexBitcodeWriter : public BitcodeWriterBase {
425   /// The combined index to write to bitcode.
426   const ModuleSummaryIndex &Index;
427 
428   /// When writing combined summaries, provides the set of global value
429   /// summaries for which the value (function, function alias, etc) should be
430   /// imported as a declaration.
431   const GVSummaryPtrSet *DecSummaries = nullptr;
432 
433   /// When writing a subset of the index for distributed backends, client
434   /// provides a map of modules to the corresponding GUIDs/summaries to write.
435   const ModuleToSummariesForIndexTy *ModuleToSummariesForIndex;
436 
437   /// Map that holds the correspondence between the GUID used in the combined
438   /// index and a value id generated by this class to use in references.
439   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
440 
441   // The stack ids used by this index, which will be a subset of those in
442   // the full index in the case of distributed indexes.
443   std::vector<uint64_t> StackIds;
444 
445   // Keep a map of the stack id indices used by records being written for this
446   // index to the index of the corresponding stack id in the above StackIds
447   // vector. Ensures we write each referenced stack id once.
448   DenseMap<unsigned, unsigned> StackIdIndicesToIndex;
449 
450   /// Tracks the last value id recorded in the GUIDToValueMap.
451   unsigned GlobalValueId = 0;
452 
453   /// Tracks the assignment of module paths in the module path string table to
454   /// an id assigned for use in summary references to the module path.
455   DenseMap<StringRef, uint64_t> ModuleIdMap;
456 
457 public:
458   /// Constructs a IndexBitcodeWriter object for the given combined index,
459   /// writing to the provided \p Buffer. When writing a subset of the index
460   /// for a distributed backend, provide a \p ModuleToSummariesForIndex map.
461   /// If provided, \p DecSummaries specifies the set of summaries for which
462   /// the corresponding functions or aliased functions should be imported as a
463   /// declaration (but not definition) for each module.
464   IndexBitcodeWriter(
465       BitstreamWriter &Stream, StringTableBuilder &StrtabBuilder,
466       const ModuleSummaryIndex &Index,
467       const GVSummaryPtrSet *DecSummaries = nullptr,
468       const ModuleToSummariesForIndexTy *ModuleToSummariesForIndex = nullptr)
469       : BitcodeWriterBase(Stream, StrtabBuilder), Index(Index),
470         DecSummaries(DecSummaries),
471         ModuleToSummariesForIndex(ModuleToSummariesForIndex) {
472 
473     // See if the StackIdIndex was already added to the StackId map and
474     // vector. If not, record it.
475     auto RecordStackIdReference = [&](unsigned StackIdIndex) {
476       // If the StackIdIndex is not yet in the map, the below insert ensures
477       // that it will point to the new StackIds vector entry we push to just
478       // below.
479       auto Inserted =
480           StackIdIndicesToIndex.insert({StackIdIndex, StackIds.size()});
481       if (Inserted.second)
482         StackIds.push_back(Index.getStackIdAtIndex(StackIdIndex));
483     };
484 
485     // Assign unique value ids to all summaries to be written, for use
486     // in writing out the call graph edges. Save the mapping from GUID
487     // to the new global value id to use when writing those edges, which
488     // are currently saved in the index in terms of GUID.
489     forEachSummary([&](GVInfo I, bool IsAliasee) {
490       GUIDToValueIdMap[I.first] = ++GlobalValueId;
491       if (IsAliasee)
492         return;
493       auto *FS = dyn_cast<FunctionSummary>(I.second);
494       if (!FS)
495         return;
496       // Record all stack id indices actually used in the summary entries being
497       // written, so that we can compact them in the case of distributed ThinLTO
498       // indexes.
499       for (auto &CI : FS->callsites()) {
500         // If the stack id list is empty, this callsite info was synthesized for
501         // a missing tail call frame. Ensure that the callee's GUID gets a value
502         // id. Normally we only generate these for defined summaries, which in
503         // the case of distributed ThinLTO is only the functions already defined
504         // in the module or that we want to import. We don't bother to include
505         // all the callee symbols as they aren't normally needed in the backend.
506         // However, for the synthesized callsite infos we do need the callee
507         // GUID in the backend so that we can correlate the identified callee
508         // with this callsite info (which for non-tail calls is done by the
509         // ordering of the callsite infos and verified via stack ids).
510         if (CI.StackIdIndices.empty()) {
511           GUIDToValueIdMap[CI.Callee.getGUID()] = ++GlobalValueId;
512           continue;
513         }
514         for (auto Idx : CI.StackIdIndices)
515           RecordStackIdReference(Idx);
516       }
517       for (auto &AI : FS->allocs())
518         for (auto &MIB : AI.MIBs)
519           for (auto Idx : MIB.StackIdIndices)
520             RecordStackIdReference(Idx);
521     });
522   }
523 
524   /// The below iterator returns the GUID and associated summary.
525   using GVInfo = std::pair<GlobalValue::GUID, GlobalValueSummary *>;
526 
527   /// Calls the callback for each value GUID and summary to be written to
528   /// bitcode. This hides the details of whether they are being pulled from the
529   /// entire index or just those in a provided ModuleToSummariesForIndex map.
530   template<typename Functor>
531   void forEachSummary(Functor Callback) {
532     if (ModuleToSummariesForIndex) {
533       for (auto &M : *ModuleToSummariesForIndex)
534         for (auto &Summary : M.second) {
535           Callback(Summary, false);
536           // Ensure aliasee is handled, e.g. for assigning a valueId,
537           // even if we are not importing the aliasee directly (the
538           // imported alias will contain a copy of aliasee).
539           if (auto *AS = dyn_cast<AliasSummary>(Summary.getSecond()))
540             Callback({AS->getAliaseeGUID(), &AS->getAliasee()}, true);
541         }
542     } else {
543       for (auto &Summaries : Index)
544         for (auto &Summary : Summaries.second.SummaryList)
545           Callback({Summaries.first, Summary.get()}, false);
546     }
547   }
548 
549   /// Calls the callback for each entry in the modulePaths StringMap that
550   /// should be written to the module path string table. This hides the details
551   /// of whether they are being pulled from the entire index or just those in a
552   /// provided ModuleToSummariesForIndex map.
553   template <typename Functor> void forEachModule(Functor Callback) {
554     if (ModuleToSummariesForIndex) {
555       for (const auto &M : *ModuleToSummariesForIndex) {
556         const auto &MPI = Index.modulePaths().find(M.first);
557         if (MPI == Index.modulePaths().end()) {
558           // This should only happen if the bitcode file was empty, in which
559           // case we shouldn't be importing (the ModuleToSummariesForIndex
560           // would only include the module we are writing and index for).
561           assert(ModuleToSummariesForIndex->size() == 1);
562           continue;
563         }
564         Callback(*MPI);
565       }
566     } else {
567       // Since StringMap iteration order isn't guaranteed, order by path string
568       // first.
569       // FIXME: Make this a vector of StringMapEntry instead to avoid the later
570       // map lookup.
571       std::vector<StringRef> ModulePaths;
572       for (auto &[ModPath, _] : Index.modulePaths())
573         ModulePaths.push_back(ModPath);
574       llvm::sort(ModulePaths.begin(), ModulePaths.end());
575       for (auto &ModPath : ModulePaths)
576         Callback(*Index.modulePaths().find(ModPath));
577     }
578   }
579 
580   /// Main entry point for writing a combined index to bitcode.
581   void write();
582 
583 private:
584   void writeModStrings();
585   void writeCombinedGlobalValueSummary();
586 
587   std::optional<unsigned> getValueId(GlobalValue::GUID ValGUID) {
588     auto VMI = GUIDToValueIdMap.find(ValGUID);
589     if (VMI == GUIDToValueIdMap.end())
590       return std::nullopt;
591     return VMI->second;
592   }
593 
594   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
595 };
596 
597 } // end anonymous namespace
598 
599 static unsigned getEncodedCastOpcode(unsigned Opcode) {
600   switch (Opcode) {
601   default: llvm_unreachable("Unknown cast instruction!");
602   case Instruction::Trunc   : return bitc::CAST_TRUNC;
603   case Instruction::ZExt    : return bitc::CAST_ZEXT;
604   case Instruction::SExt    : return bitc::CAST_SEXT;
605   case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
606   case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
607   case Instruction::UIToFP  : return bitc::CAST_UITOFP;
608   case Instruction::SIToFP  : return bitc::CAST_SITOFP;
609   case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
610   case Instruction::FPExt   : return bitc::CAST_FPEXT;
611   case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
612   case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
613   case Instruction::BitCast : return bitc::CAST_BITCAST;
614   case Instruction::AddrSpaceCast: return bitc::CAST_ADDRSPACECAST;
615   }
616 }
617 
618 static unsigned getEncodedUnaryOpcode(unsigned Opcode) {
619   switch (Opcode) {
620   default: llvm_unreachable("Unknown binary instruction!");
621   case Instruction::FNeg: return bitc::UNOP_FNEG;
622   }
623 }
624 
625 static unsigned getEncodedBinaryOpcode(unsigned Opcode) {
626   switch (Opcode) {
627   default: llvm_unreachable("Unknown binary instruction!");
628   case Instruction::Add:
629   case Instruction::FAdd: return bitc::BINOP_ADD;
630   case Instruction::Sub:
631   case Instruction::FSub: return bitc::BINOP_SUB;
632   case Instruction::Mul:
633   case Instruction::FMul: return bitc::BINOP_MUL;
634   case Instruction::UDiv: return bitc::BINOP_UDIV;
635   case Instruction::FDiv:
636   case Instruction::SDiv: return bitc::BINOP_SDIV;
637   case Instruction::URem: return bitc::BINOP_UREM;
638   case Instruction::FRem:
639   case Instruction::SRem: return bitc::BINOP_SREM;
640   case Instruction::Shl:  return bitc::BINOP_SHL;
641   case Instruction::LShr: return bitc::BINOP_LSHR;
642   case Instruction::AShr: return bitc::BINOP_ASHR;
643   case Instruction::And:  return bitc::BINOP_AND;
644   case Instruction::Or:   return bitc::BINOP_OR;
645   case Instruction::Xor:  return bitc::BINOP_XOR;
646   }
647 }
648 
649 static unsigned getEncodedRMWOperation(AtomicRMWInst::BinOp Op) {
650   switch (Op) {
651   default: llvm_unreachable("Unknown RMW operation!");
652   case AtomicRMWInst::Xchg: return bitc::RMW_XCHG;
653   case AtomicRMWInst::Add: return bitc::RMW_ADD;
654   case AtomicRMWInst::Sub: return bitc::RMW_SUB;
655   case AtomicRMWInst::And: return bitc::RMW_AND;
656   case AtomicRMWInst::Nand: return bitc::RMW_NAND;
657   case AtomicRMWInst::Or: return bitc::RMW_OR;
658   case AtomicRMWInst::Xor: return bitc::RMW_XOR;
659   case AtomicRMWInst::Max: return bitc::RMW_MAX;
660   case AtomicRMWInst::Min: return bitc::RMW_MIN;
661   case AtomicRMWInst::UMax: return bitc::RMW_UMAX;
662   case AtomicRMWInst::UMin: return bitc::RMW_UMIN;
663   case AtomicRMWInst::FAdd: return bitc::RMW_FADD;
664   case AtomicRMWInst::FSub: return bitc::RMW_FSUB;
665   case AtomicRMWInst::FMax: return bitc::RMW_FMAX;
666   case AtomicRMWInst::FMin: return bitc::RMW_FMIN;
667   case AtomicRMWInst::UIncWrap:
668     return bitc::RMW_UINC_WRAP;
669   case AtomicRMWInst::UDecWrap:
670     return bitc::RMW_UDEC_WRAP;
671   case AtomicRMWInst::USubCond:
672     return bitc::RMW_USUB_COND;
673   case AtomicRMWInst::USubSat:
674     return bitc::RMW_USUB_SAT;
675   }
676 }
677 
678 static unsigned getEncodedOrdering(AtomicOrdering Ordering) {
679   switch (Ordering) {
680   case AtomicOrdering::NotAtomic: return bitc::ORDERING_NOTATOMIC;
681   case AtomicOrdering::Unordered: return bitc::ORDERING_UNORDERED;
682   case AtomicOrdering::Monotonic: return bitc::ORDERING_MONOTONIC;
683   case AtomicOrdering::Acquire: return bitc::ORDERING_ACQUIRE;
684   case AtomicOrdering::Release: return bitc::ORDERING_RELEASE;
685   case AtomicOrdering::AcquireRelease: return bitc::ORDERING_ACQREL;
686   case AtomicOrdering::SequentiallyConsistent: return bitc::ORDERING_SEQCST;
687   }
688   llvm_unreachable("Invalid ordering");
689 }
690 
691 static void writeStringRecord(BitstreamWriter &Stream, unsigned Code,
692                               StringRef Str, unsigned AbbrevToUse) {
693   SmallVector<unsigned, 64> Vals;
694 
695   // Code: [strchar x N]
696   for (char C : Str) {
697     if (AbbrevToUse && !BitCodeAbbrevOp::isChar6(C))
698       AbbrevToUse = 0;
699     Vals.push_back(C);
700   }
701 
702   // Emit the finished record.
703   Stream.EmitRecord(Code, Vals, AbbrevToUse);
704 }
705 
706 static uint64_t getAttrKindEncoding(Attribute::AttrKind Kind) {
707   switch (Kind) {
708   case Attribute::Alignment:
709     return bitc::ATTR_KIND_ALIGNMENT;
710   case Attribute::AllocAlign:
711     return bitc::ATTR_KIND_ALLOC_ALIGN;
712   case Attribute::AllocSize:
713     return bitc::ATTR_KIND_ALLOC_SIZE;
714   case Attribute::AlwaysInline:
715     return bitc::ATTR_KIND_ALWAYS_INLINE;
716   case Attribute::Builtin:
717     return bitc::ATTR_KIND_BUILTIN;
718   case Attribute::ByVal:
719     return bitc::ATTR_KIND_BY_VAL;
720   case Attribute::Convergent:
721     return bitc::ATTR_KIND_CONVERGENT;
722   case Attribute::InAlloca:
723     return bitc::ATTR_KIND_IN_ALLOCA;
724   case Attribute::Cold:
725     return bitc::ATTR_KIND_COLD;
726   case Attribute::DisableSanitizerInstrumentation:
727     return bitc::ATTR_KIND_DISABLE_SANITIZER_INSTRUMENTATION;
728   case Attribute::FnRetThunkExtern:
729     return bitc::ATTR_KIND_FNRETTHUNK_EXTERN;
730   case Attribute::Hot:
731     return bitc::ATTR_KIND_HOT;
732   case Attribute::ElementType:
733     return bitc::ATTR_KIND_ELEMENTTYPE;
734   case Attribute::HybridPatchable:
735     return bitc::ATTR_KIND_HYBRID_PATCHABLE;
736   case Attribute::InlineHint:
737     return bitc::ATTR_KIND_INLINE_HINT;
738   case Attribute::InReg:
739     return bitc::ATTR_KIND_IN_REG;
740   case Attribute::JumpTable:
741     return bitc::ATTR_KIND_JUMP_TABLE;
742   case Attribute::MinSize:
743     return bitc::ATTR_KIND_MIN_SIZE;
744   case Attribute::AllocatedPointer:
745     return bitc::ATTR_KIND_ALLOCATED_POINTER;
746   case Attribute::AllocKind:
747     return bitc::ATTR_KIND_ALLOC_KIND;
748   case Attribute::Memory:
749     return bitc::ATTR_KIND_MEMORY;
750   case Attribute::NoFPClass:
751     return bitc::ATTR_KIND_NOFPCLASS;
752   case Attribute::Naked:
753     return bitc::ATTR_KIND_NAKED;
754   case Attribute::Nest:
755     return bitc::ATTR_KIND_NEST;
756   case Attribute::NoAlias:
757     return bitc::ATTR_KIND_NO_ALIAS;
758   case Attribute::NoBuiltin:
759     return bitc::ATTR_KIND_NO_BUILTIN;
760   case Attribute::NoCallback:
761     return bitc::ATTR_KIND_NO_CALLBACK;
762   case Attribute::NoCapture:
763     return bitc::ATTR_KIND_NO_CAPTURE;
764   case Attribute::NoDuplicate:
765     return bitc::ATTR_KIND_NO_DUPLICATE;
766   case Attribute::NoFree:
767     return bitc::ATTR_KIND_NOFREE;
768   case Attribute::NoImplicitFloat:
769     return bitc::ATTR_KIND_NO_IMPLICIT_FLOAT;
770   case Attribute::NoInline:
771     return bitc::ATTR_KIND_NO_INLINE;
772   case Attribute::NoRecurse:
773     return bitc::ATTR_KIND_NO_RECURSE;
774   case Attribute::NoMerge:
775     return bitc::ATTR_KIND_NO_MERGE;
776   case Attribute::NonLazyBind:
777     return bitc::ATTR_KIND_NON_LAZY_BIND;
778   case Attribute::NonNull:
779     return bitc::ATTR_KIND_NON_NULL;
780   case Attribute::Dereferenceable:
781     return bitc::ATTR_KIND_DEREFERENCEABLE;
782   case Attribute::DereferenceableOrNull:
783     return bitc::ATTR_KIND_DEREFERENCEABLE_OR_NULL;
784   case Attribute::NoRedZone:
785     return bitc::ATTR_KIND_NO_RED_ZONE;
786   case Attribute::NoReturn:
787     return bitc::ATTR_KIND_NO_RETURN;
788   case Attribute::NoSync:
789     return bitc::ATTR_KIND_NOSYNC;
790   case Attribute::NoCfCheck:
791     return bitc::ATTR_KIND_NOCF_CHECK;
792   case Attribute::NoProfile:
793     return bitc::ATTR_KIND_NO_PROFILE;
794   case Attribute::SkipProfile:
795     return bitc::ATTR_KIND_SKIP_PROFILE;
796   case Attribute::NoUnwind:
797     return bitc::ATTR_KIND_NO_UNWIND;
798   case Attribute::NoSanitizeBounds:
799     return bitc::ATTR_KIND_NO_SANITIZE_BOUNDS;
800   case Attribute::NoSanitizeCoverage:
801     return bitc::ATTR_KIND_NO_SANITIZE_COVERAGE;
802   case Attribute::NullPointerIsValid:
803     return bitc::ATTR_KIND_NULL_POINTER_IS_VALID;
804   case Attribute::OptimizeForDebugging:
805     return bitc::ATTR_KIND_OPTIMIZE_FOR_DEBUGGING;
806   case Attribute::OptForFuzzing:
807     return bitc::ATTR_KIND_OPT_FOR_FUZZING;
808   case Attribute::OptimizeForSize:
809     return bitc::ATTR_KIND_OPTIMIZE_FOR_SIZE;
810   case Attribute::OptimizeNone:
811     return bitc::ATTR_KIND_OPTIMIZE_NONE;
812   case Attribute::ReadNone:
813     return bitc::ATTR_KIND_READ_NONE;
814   case Attribute::ReadOnly:
815     return bitc::ATTR_KIND_READ_ONLY;
816   case Attribute::Returned:
817     return bitc::ATTR_KIND_RETURNED;
818   case Attribute::ReturnsTwice:
819     return bitc::ATTR_KIND_RETURNS_TWICE;
820   case Attribute::SExt:
821     return bitc::ATTR_KIND_S_EXT;
822   case Attribute::Speculatable:
823     return bitc::ATTR_KIND_SPECULATABLE;
824   case Attribute::StackAlignment:
825     return bitc::ATTR_KIND_STACK_ALIGNMENT;
826   case Attribute::StackProtect:
827     return bitc::ATTR_KIND_STACK_PROTECT;
828   case Attribute::StackProtectReq:
829     return bitc::ATTR_KIND_STACK_PROTECT_REQ;
830   case Attribute::StackProtectStrong:
831     return bitc::ATTR_KIND_STACK_PROTECT_STRONG;
832   case Attribute::SafeStack:
833     return bitc::ATTR_KIND_SAFESTACK;
834   case Attribute::ShadowCallStack:
835     return bitc::ATTR_KIND_SHADOWCALLSTACK;
836   case Attribute::StrictFP:
837     return bitc::ATTR_KIND_STRICT_FP;
838   case Attribute::StructRet:
839     return bitc::ATTR_KIND_STRUCT_RET;
840   case Attribute::SanitizeAddress:
841     return bitc::ATTR_KIND_SANITIZE_ADDRESS;
842   case Attribute::SanitizeHWAddress:
843     return bitc::ATTR_KIND_SANITIZE_HWADDRESS;
844   case Attribute::SanitizeThread:
845     return bitc::ATTR_KIND_SANITIZE_THREAD;
846   case Attribute::SanitizeMemory:
847     return bitc::ATTR_KIND_SANITIZE_MEMORY;
848   case Attribute::SanitizeNumericalStability:
849     return bitc::ATTR_KIND_SANITIZE_NUMERICAL_STABILITY;
850   case Attribute::SanitizeRealtime:
851     return bitc::ATTR_KIND_SANITIZE_REALTIME;
852   case Attribute::SpeculativeLoadHardening:
853     return bitc::ATTR_KIND_SPECULATIVE_LOAD_HARDENING;
854   case Attribute::SwiftError:
855     return bitc::ATTR_KIND_SWIFT_ERROR;
856   case Attribute::SwiftSelf:
857     return bitc::ATTR_KIND_SWIFT_SELF;
858   case Attribute::SwiftAsync:
859     return bitc::ATTR_KIND_SWIFT_ASYNC;
860   case Attribute::UWTable:
861     return bitc::ATTR_KIND_UW_TABLE;
862   case Attribute::VScaleRange:
863     return bitc::ATTR_KIND_VSCALE_RANGE;
864   case Attribute::WillReturn:
865     return bitc::ATTR_KIND_WILLRETURN;
866   case Attribute::WriteOnly:
867     return bitc::ATTR_KIND_WRITEONLY;
868   case Attribute::ZExt:
869     return bitc::ATTR_KIND_Z_EXT;
870   case Attribute::ImmArg:
871     return bitc::ATTR_KIND_IMMARG;
872   case Attribute::SanitizeMemTag:
873     return bitc::ATTR_KIND_SANITIZE_MEMTAG;
874   case Attribute::Preallocated:
875     return bitc::ATTR_KIND_PREALLOCATED;
876   case Attribute::NoUndef:
877     return bitc::ATTR_KIND_NOUNDEF;
878   case Attribute::ByRef:
879     return bitc::ATTR_KIND_BYREF;
880   case Attribute::MustProgress:
881     return bitc::ATTR_KIND_MUSTPROGRESS;
882   case Attribute::PresplitCoroutine:
883     return bitc::ATTR_KIND_PRESPLIT_COROUTINE;
884   case Attribute::Writable:
885     return bitc::ATTR_KIND_WRITABLE;
886   case Attribute::CoroDestroyOnlyWhenComplete:
887     return bitc::ATTR_KIND_CORO_ONLY_DESTROY_WHEN_COMPLETE;
888   case Attribute::CoroElideSafe:
889     return bitc::ATTR_KIND_CORO_ELIDE_SAFE;
890   case Attribute::DeadOnUnwind:
891     return bitc::ATTR_KIND_DEAD_ON_UNWIND;
892   case Attribute::Range:
893     return bitc::ATTR_KIND_RANGE;
894   case Attribute::Initializes:
895     return bitc::ATTR_KIND_INITIALIZES;
896   case Attribute::NoExt:
897     return bitc::ATTR_KIND_NO_EXT;
898   case Attribute::EndAttrKinds:
899     llvm_unreachable("Can not encode end-attribute kinds marker.");
900   case Attribute::None:
901     llvm_unreachable("Can not encode none-attribute.");
902   case Attribute::EmptyKey:
903   case Attribute::TombstoneKey:
904     llvm_unreachable("Trying to encode EmptyKey/TombstoneKey");
905   }
906 
907   llvm_unreachable("Trying to encode unknown attribute");
908 }
909 
910 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
911   if ((int64_t)V >= 0)
912     Vals.push_back(V << 1);
913   else
914     Vals.push_back((-V << 1) | 1);
915 }
916 
917 static void emitWideAPInt(SmallVectorImpl<uint64_t> &Vals, const APInt &A) {
918   // We have an arbitrary precision integer value to write whose
919   // bit width is > 64. However, in canonical unsigned integer
920   // format it is likely that the high bits are going to be zero.
921   // So, we only write the number of active words.
922   unsigned NumWords = A.getActiveWords();
923   const uint64_t *RawData = A.getRawData();
924   for (unsigned i = 0; i < NumWords; i++)
925     emitSignedInt64(Vals, RawData[i]);
926 }
927 
928 static void emitConstantRange(SmallVectorImpl<uint64_t> &Record,
929                               const ConstantRange &CR, bool EmitBitWidth) {
930   unsigned BitWidth = CR.getBitWidth();
931   if (EmitBitWidth)
932     Record.push_back(BitWidth);
933   if (BitWidth > 64) {
934     Record.push_back(CR.getLower().getActiveWords() |
935                      (uint64_t(CR.getUpper().getActiveWords()) << 32));
936     emitWideAPInt(Record, CR.getLower());
937     emitWideAPInt(Record, CR.getUpper());
938   } else {
939     emitSignedInt64(Record, CR.getLower().getSExtValue());
940     emitSignedInt64(Record, CR.getUpper().getSExtValue());
941   }
942 }
943 
944 void ModuleBitcodeWriter::writeAttributeGroupTable() {
945   const std::vector<ValueEnumerator::IndexAndAttrSet> &AttrGrps =
946       VE.getAttributeGroups();
947   if (AttrGrps.empty()) return;
948 
949   Stream.EnterSubblock(bitc::PARAMATTR_GROUP_BLOCK_ID, 3);
950 
951   SmallVector<uint64_t, 64> Record;
952   for (ValueEnumerator::IndexAndAttrSet Pair : AttrGrps) {
953     unsigned AttrListIndex = Pair.first;
954     AttributeSet AS = Pair.second;
955     Record.push_back(VE.getAttributeGroupID(Pair));
956     Record.push_back(AttrListIndex);
957 
958     for (Attribute Attr : AS) {
959       if (Attr.isEnumAttribute()) {
960         Record.push_back(0);
961         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
962       } else if (Attr.isIntAttribute()) {
963         Record.push_back(1);
964         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
965         Record.push_back(Attr.getValueAsInt());
966       } else if (Attr.isStringAttribute()) {
967         StringRef Kind = Attr.getKindAsString();
968         StringRef Val = Attr.getValueAsString();
969 
970         Record.push_back(Val.empty() ? 3 : 4);
971         Record.append(Kind.begin(), Kind.end());
972         Record.push_back(0);
973         if (!Val.empty()) {
974           Record.append(Val.begin(), Val.end());
975           Record.push_back(0);
976         }
977       } else if (Attr.isTypeAttribute()) {
978         Type *Ty = Attr.getValueAsType();
979         Record.push_back(Ty ? 6 : 5);
980         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
981         if (Ty)
982           Record.push_back(VE.getTypeID(Attr.getValueAsType()));
983       } else if (Attr.isConstantRangeAttribute()) {
984         Record.push_back(7);
985         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
986         emitConstantRange(Record, Attr.getValueAsConstantRange(),
987                           /*EmitBitWidth=*/true);
988       } else {
989         assert(Attr.isConstantRangeListAttribute());
990         Record.push_back(8);
991         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
992         ArrayRef<ConstantRange> Val = Attr.getValueAsConstantRangeList();
993         Record.push_back(Val.size());
994         Record.push_back(Val[0].getBitWidth());
995         for (auto &CR : Val)
996           emitConstantRange(Record, CR, /*EmitBitWidth=*/false);
997       }
998     }
999 
1000     Stream.EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
1001     Record.clear();
1002   }
1003 
1004   Stream.ExitBlock();
1005 }
1006 
1007 void ModuleBitcodeWriter::writeAttributeTable() {
1008   const std::vector<AttributeList> &Attrs = VE.getAttributeLists();
1009   if (Attrs.empty()) return;
1010 
1011   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
1012 
1013   SmallVector<uint64_t, 64> Record;
1014   for (const AttributeList &AL : Attrs) {
1015     for (unsigned i : AL.indexes()) {
1016       AttributeSet AS = AL.getAttributes(i);
1017       if (AS.hasAttributes())
1018         Record.push_back(VE.getAttributeGroupID({i, AS}));
1019     }
1020 
1021     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
1022     Record.clear();
1023   }
1024 
1025   Stream.ExitBlock();
1026 }
1027 
1028 /// WriteTypeTable - Write out the type table for a module.
1029 void ModuleBitcodeWriter::writeTypeTable() {
1030   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
1031 
1032   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
1033   SmallVector<uint64_t, 64> TypeVals;
1034 
1035   uint64_t NumBits = VE.computeBitsRequiredForTypeIndices();
1036 
1037   // Abbrev for TYPE_CODE_OPAQUE_POINTER.
1038   auto Abbv = std::make_shared<BitCodeAbbrev>();
1039   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_OPAQUE_POINTER));
1040   Abbv->Add(BitCodeAbbrevOp(0)); // Addrspace = 0
1041   unsigned OpaquePtrAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1042 
1043   // Abbrev for TYPE_CODE_FUNCTION.
1044   Abbv = std::make_shared<BitCodeAbbrev>();
1045   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
1046   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
1047   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1048   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
1049   unsigned FunctionAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1050 
1051   // Abbrev for TYPE_CODE_STRUCT_ANON.
1052   Abbv = std::make_shared<BitCodeAbbrev>();
1053   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
1054   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
1055   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1056   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
1057   unsigned StructAnonAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1058 
1059   // Abbrev for TYPE_CODE_STRUCT_NAME.
1060   Abbv = std::make_shared<BitCodeAbbrev>();
1061   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
1062   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1063   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1064   unsigned StructNameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1065 
1066   // Abbrev for TYPE_CODE_STRUCT_NAMED.
1067   Abbv = std::make_shared<BitCodeAbbrev>();
1068   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
1069   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
1070   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1071   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
1072   unsigned StructNamedAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1073 
1074   // Abbrev for TYPE_CODE_ARRAY.
1075   Abbv = std::make_shared<BitCodeAbbrev>();
1076   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
1077   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
1078   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
1079   unsigned ArrayAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1080 
1081   // Emit an entry count so the reader can reserve space.
1082   TypeVals.push_back(TypeList.size());
1083   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
1084   TypeVals.clear();
1085 
1086   // Loop over all of the types, emitting each in turn.
1087   for (Type *T : TypeList) {
1088     int AbbrevToUse = 0;
1089     unsigned Code = 0;
1090 
1091     switch (T->getTypeID()) {
1092     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;      break;
1093     case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;      break;
1094     case Type::BFloatTyID:    Code = bitc::TYPE_CODE_BFLOAT;    break;
1095     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;     break;
1096     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE;    break;
1097     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80;  break;
1098     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128;     break;
1099     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
1100     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;     break;
1101     case Type::MetadataTyID:
1102       Code = bitc::TYPE_CODE_METADATA;
1103       break;
1104     case Type::X86_AMXTyID:   Code = bitc::TYPE_CODE_X86_AMX;   break;
1105     case Type::TokenTyID:     Code = bitc::TYPE_CODE_TOKEN;     break;
1106     case Type::IntegerTyID:
1107       // INTEGER: [width]
1108       Code = bitc::TYPE_CODE_INTEGER;
1109       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
1110       break;
1111     case Type::PointerTyID: {
1112       PointerType *PTy = cast<PointerType>(T);
1113       unsigned AddressSpace = PTy->getAddressSpace();
1114       // OPAQUE_POINTER: [address space]
1115       Code = bitc::TYPE_CODE_OPAQUE_POINTER;
1116       TypeVals.push_back(AddressSpace);
1117       if (AddressSpace == 0)
1118         AbbrevToUse = OpaquePtrAbbrev;
1119       break;
1120     }
1121     case Type::FunctionTyID: {
1122       FunctionType *FT = cast<FunctionType>(T);
1123       // FUNCTION: [isvararg, retty, paramty x N]
1124       Code = bitc::TYPE_CODE_FUNCTION;
1125       TypeVals.push_back(FT->isVarArg());
1126       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
1127       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
1128         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
1129       AbbrevToUse = FunctionAbbrev;
1130       break;
1131     }
1132     case Type::StructTyID: {
1133       StructType *ST = cast<StructType>(T);
1134       // STRUCT: [ispacked, eltty x N]
1135       TypeVals.push_back(ST->isPacked());
1136       // Output all of the element types.
1137       for (Type *ET : ST->elements())
1138         TypeVals.push_back(VE.getTypeID(ET));
1139 
1140       if (ST->isLiteral()) {
1141         Code = bitc::TYPE_CODE_STRUCT_ANON;
1142         AbbrevToUse = StructAnonAbbrev;
1143       } else {
1144         if (ST->isOpaque()) {
1145           Code = bitc::TYPE_CODE_OPAQUE;
1146         } else {
1147           Code = bitc::TYPE_CODE_STRUCT_NAMED;
1148           AbbrevToUse = StructNamedAbbrev;
1149         }
1150 
1151         // Emit the name if it is present.
1152         if (!ST->getName().empty())
1153           writeStringRecord(Stream, bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
1154                             StructNameAbbrev);
1155       }
1156       break;
1157     }
1158     case Type::ArrayTyID: {
1159       ArrayType *AT = cast<ArrayType>(T);
1160       // ARRAY: [numelts, eltty]
1161       Code = bitc::TYPE_CODE_ARRAY;
1162       TypeVals.push_back(AT->getNumElements());
1163       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
1164       AbbrevToUse = ArrayAbbrev;
1165       break;
1166     }
1167     case Type::FixedVectorTyID:
1168     case Type::ScalableVectorTyID: {
1169       VectorType *VT = cast<VectorType>(T);
1170       // VECTOR [numelts, eltty] or
1171       //        [numelts, eltty, scalable]
1172       Code = bitc::TYPE_CODE_VECTOR;
1173       TypeVals.push_back(VT->getElementCount().getKnownMinValue());
1174       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
1175       if (isa<ScalableVectorType>(VT))
1176         TypeVals.push_back(true);
1177       break;
1178     }
1179     case Type::TargetExtTyID: {
1180       TargetExtType *TET = cast<TargetExtType>(T);
1181       Code = bitc::TYPE_CODE_TARGET_TYPE;
1182       writeStringRecord(Stream, bitc::TYPE_CODE_STRUCT_NAME, TET->getName(),
1183                         StructNameAbbrev);
1184       TypeVals.push_back(TET->getNumTypeParameters());
1185       for (Type *InnerTy : TET->type_params())
1186         TypeVals.push_back(VE.getTypeID(InnerTy));
1187       for (unsigned IntParam : TET->int_params())
1188         TypeVals.push_back(IntParam);
1189       break;
1190     }
1191     case Type::TypedPointerTyID:
1192       llvm_unreachable("Typed pointers cannot be added to IR modules");
1193     }
1194 
1195     // Emit the finished record.
1196     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
1197     TypeVals.clear();
1198   }
1199 
1200   Stream.ExitBlock();
1201 }
1202 
1203 static unsigned getEncodedLinkage(const GlobalValue::LinkageTypes Linkage) {
1204   switch (Linkage) {
1205   case GlobalValue::ExternalLinkage:
1206     return 0;
1207   case GlobalValue::WeakAnyLinkage:
1208     return 16;
1209   case GlobalValue::AppendingLinkage:
1210     return 2;
1211   case GlobalValue::InternalLinkage:
1212     return 3;
1213   case GlobalValue::LinkOnceAnyLinkage:
1214     return 18;
1215   case GlobalValue::ExternalWeakLinkage:
1216     return 7;
1217   case GlobalValue::CommonLinkage:
1218     return 8;
1219   case GlobalValue::PrivateLinkage:
1220     return 9;
1221   case GlobalValue::WeakODRLinkage:
1222     return 17;
1223   case GlobalValue::LinkOnceODRLinkage:
1224     return 19;
1225   case GlobalValue::AvailableExternallyLinkage:
1226     return 12;
1227   }
1228   llvm_unreachable("Invalid linkage");
1229 }
1230 
1231 static unsigned getEncodedLinkage(const GlobalValue &GV) {
1232   return getEncodedLinkage(GV.getLinkage());
1233 }
1234 
1235 static uint64_t getEncodedFFlags(FunctionSummary::FFlags Flags) {
1236   uint64_t RawFlags = 0;
1237   RawFlags |= Flags.ReadNone;
1238   RawFlags |= (Flags.ReadOnly << 1);
1239   RawFlags |= (Flags.NoRecurse << 2);
1240   RawFlags |= (Flags.ReturnDoesNotAlias << 3);
1241   RawFlags |= (Flags.NoInline << 4);
1242   RawFlags |= (Flags.AlwaysInline << 5);
1243   RawFlags |= (Flags.NoUnwind << 6);
1244   RawFlags |= (Flags.MayThrow << 7);
1245   RawFlags |= (Flags.HasUnknownCall << 8);
1246   RawFlags |= (Flags.MustBeUnreachable << 9);
1247   return RawFlags;
1248 }
1249 
1250 // Decode the flags for GlobalValue in the summary. See getDecodedGVSummaryFlags
1251 // in BitcodeReader.cpp.
1252 static uint64_t getEncodedGVSummaryFlags(GlobalValueSummary::GVFlags Flags,
1253                                          bool ImportAsDecl = false) {
1254   uint64_t RawFlags = 0;
1255 
1256   RawFlags |= Flags.NotEligibleToImport; // bool
1257   RawFlags |= (Flags.Live << 1);
1258   RawFlags |= (Flags.DSOLocal << 2);
1259   RawFlags |= (Flags.CanAutoHide << 3);
1260 
1261   // Linkage don't need to be remapped at that time for the summary. Any future
1262   // change to the getEncodedLinkage() function will need to be taken into
1263   // account here as well.
1264   RawFlags = (RawFlags << 4) | Flags.Linkage; // 4 bits
1265 
1266   RawFlags |= (Flags.Visibility << 8); // 2 bits
1267 
1268   unsigned ImportType = Flags.ImportType | ImportAsDecl;
1269   RawFlags |= (ImportType << 10); // 1 bit
1270 
1271   return RawFlags;
1272 }
1273 
1274 static uint64_t getEncodedGVarFlags(GlobalVarSummary::GVarFlags Flags) {
1275   uint64_t RawFlags = Flags.MaybeReadOnly | (Flags.MaybeWriteOnly << 1) |
1276                       (Flags.Constant << 2) | Flags.VCallVisibility << 3;
1277   return RawFlags;
1278 }
1279 
1280 static uint64_t getEncodedHotnessCallEdgeInfo(const CalleeInfo &CI) {
1281   uint64_t RawFlags = 0;
1282 
1283   RawFlags |= CI.Hotness;            // 3 bits
1284   RawFlags |= (CI.HasTailCall << 3); // 1 bit
1285 
1286   return RawFlags;
1287 }
1288 
1289 static uint64_t getEncodedRelBFCallEdgeInfo(const CalleeInfo &CI) {
1290   uint64_t RawFlags = 0;
1291 
1292   RawFlags |= CI.RelBlockFreq; // CalleeInfo::RelBlockFreqBits bits
1293   RawFlags |= (CI.HasTailCall << CalleeInfo::RelBlockFreqBits); // 1 bit
1294 
1295   return RawFlags;
1296 }
1297 
1298 static unsigned getEncodedVisibility(const GlobalValue &GV) {
1299   switch (GV.getVisibility()) {
1300   case GlobalValue::DefaultVisibility:   return 0;
1301   case GlobalValue::HiddenVisibility:    return 1;
1302   case GlobalValue::ProtectedVisibility: return 2;
1303   }
1304   llvm_unreachable("Invalid visibility");
1305 }
1306 
1307 static unsigned getEncodedDLLStorageClass(const GlobalValue &GV) {
1308   switch (GV.getDLLStorageClass()) {
1309   case GlobalValue::DefaultStorageClass:   return 0;
1310   case GlobalValue::DLLImportStorageClass: return 1;
1311   case GlobalValue::DLLExportStorageClass: return 2;
1312   }
1313   llvm_unreachable("Invalid DLL storage class");
1314 }
1315 
1316 static unsigned getEncodedThreadLocalMode(const GlobalValue &GV) {
1317   switch (GV.getThreadLocalMode()) {
1318     case GlobalVariable::NotThreadLocal:         return 0;
1319     case GlobalVariable::GeneralDynamicTLSModel: return 1;
1320     case GlobalVariable::LocalDynamicTLSModel:   return 2;
1321     case GlobalVariable::InitialExecTLSModel:    return 3;
1322     case GlobalVariable::LocalExecTLSModel:      return 4;
1323   }
1324   llvm_unreachable("Invalid TLS model");
1325 }
1326 
1327 static unsigned getEncodedComdatSelectionKind(const Comdat &C) {
1328   switch (C.getSelectionKind()) {
1329   case Comdat::Any:
1330     return bitc::COMDAT_SELECTION_KIND_ANY;
1331   case Comdat::ExactMatch:
1332     return bitc::COMDAT_SELECTION_KIND_EXACT_MATCH;
1333   case Comdat::Largest:
1334     return bitc::COMDAT_SELECTION_KIND_LARGEST;
1335   case Comdat::NoDeduplicate:
1336     return bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES;
1337   case Comdat::SameSize:
1338     return bitc::COMDAT_SELECTION_KIND_SAME_SIZE;
1339   }
1340   llvm_unreachable("Invalid selection kind");
1341 }
1342 
1343 static unsigned getEncodedUnnamedAddr(const GlobalValue &GV) {
1344   switch (GV.getUnnamedAddr()) {
1345   case GlobalValue::UnnamedAddr::None:   return 0;
1346   case GlobalValue::UnnamedAddr::Local:  return 2;
1347   case GlobalValue::UnnamedAddr::Global: return 1;
1348   }
1349   llvm_unreachable("Invalid unnamed_addr");
1350 }
1351 
1352 size_t ModuleBitcodeWriter::addToStrtab(StringRef Str) {
1353   if (GenerateHash)
1354     Hasher.update(Str);
1355   return StrtabBuilder.add(Str);
1356 }
1357 
1358 void ModuleBitcodeWriter::writeComdats() {
1359   SmallVector<unsigned, 64> Vals;
1360   for (const Comdat *C : VE.getComdats()) {
1361     // COMDAT: [strtab offset, strtab size, selection_kind]
1362     Vals.push_back(addToStrtab(C->getName()));
1363     Vals.push_back(C->getName().size());
1364     Vals.push_back(getEncodedComdatSelectionKind(*C));
1365     Stream.EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
1366     Vals.clear();
1367   }
1368 }
1369 
1370 /// Write a record that will eventually hold the word offset of the
1371 /// module-level VST. For now the offset is 0, which will be backpatched
1372 /// after the real VST is written. Saves the bit offset to backpatch.
1373 void ModuleBitcodeWriter::writeValueSymbolTableForwardDecl() {
1374   // Write a placeholder value in for the offset of the real VST,
1375   // which is written after the function blocks so that it can include
1376   // the offset of each function. The placeholder offset will be
1377   // updated when the real VST is written.
1378   auto Abbv = std::make_shared<BitCodeAbbrev>();
1379   Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_VSTOFFSET));
1380   // Blocks are 32-bit aligned, so we can use a 32-bit word offset to
1381   // hold the real VST offset. Must use fixed instead of VBR as we don't
1382   // know how many VBR chunks to reserve ahead of time.
1383   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
1384   unsigned VSTOffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1385 
1386   // Emit the placeholder
1387   uint64_t Vals[] = {bitc::MODULE_CODE_VSTOFFSET, 0};
1388   Stream.EmitRecordWithAbbrev(VSTOffsetAbbrev, Vals);
1389 
1390   // Compute and save the bit offset to the placeholder, which will be
1391   // patched when the real VST is written. We can simply subtract the 32-bit
1392   // fixed size from the current bit number to get the location to backpatch.
1393   VSTOffsetPlaceholder = Stream.GetCurrentBitNo() - 32;
1394 }
1395 
1396 enum StringEncoding { SE_Char6, SE_Fixed7, SE_Fixed8 };
1397 
1398 /// Determine the encoding to use for the given string name and length.
1399 static StringEncoding getStringEncoding(StringRef Str) {
1400   bool isChar6 = true;
1401   for (char C : Str) {
1402     if (isChar6)
1403       isChar6 = BitCodeAbbrevOp::isChar6(C);
1404     if ((unsigned char)C & 128)
1405       // don't bother scanning the rest.
1406       return SE_Fixed8;
1407   }
1408   if (isChar6)
1409     return SE_Char6;
1410   return SE_Fixed7;
1411 }
1412 
1413 static_assert(sizeof(GlobalValue::SanitizerMetadata) <= sizeof(unsigned),
1414               "Sanitizer Metadata is too large for naive serialization.");
1415 static unsigned
1416 serializeSanitizerMetadata(const GlobalValue::SanitizerMetadata &Meta) {
1417   return Meta.NoAddress | (Meta.NoHWAddress << 1) |
1418          (Meta.Memtag << 2) | (Meta.IsDynInit << 3);
1419 }
1420 
1421 /// Emit top-level description of module, including target triple, inline asm,
1422 /// descriptors for global variables, and function prototype info.
1423 /// Returns the bit offset to backpatch with the location of the real VST.
1424 void ModuleBitcodeWriter::writeModuleInfo() {
1425   // Emit various pieces of data attached to a module.
1426   if (!M.getTargetTriple().empty())
1427     writeStringRecord(Stream, bitc::MODULE_CODE_TRIPLE, M.getTargetTriple(),
1428                       0 /*TODO*/);
1429   const std::string &DL = M.getDataLayoutStr();
1430   if (!DL.empty())
1431     writeStringRecord(Stream, bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/);
1432   if (!M.getModuleInlineAsm().empty())
1433     writeStringRecord(Stream, bitc::MODULE_CODE_ASM, M.getModuleInlineAsm(),
1434                       0 /*TODO*/);
1435 
1436   // Emit information about sections and GC, computing how many there are. Also
1437   // compute the maximum alignment value.
1438   std::map<std::string, unsigned> SectionMap;
1439   std::map<std::string, unsigned> GCMap;
1440   MaybeAlign MaxAlignment;
1441   unsigned MaxGlobalType = 0;
1442   const auto UpdateMaxAlignment = [&MaxAlignment](const MaybeAlign A) {
1443     if (A)
1444       MaxAlignment = !MaxAlignment ? *A : std::max(*MaxAlignment, *A);
1445   };
1446   for (const GlobalVariable &GV : M.globals()) {
1447     UpdateMaxAlignment(GV.getAlign());
1448     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getValueType()));
1449     if (GV.hasSection()) {
1450       // Give section names unique ID's.
1451       unsigned &Entry = SectionMap[std::string(GV.getSection())];
1452       if (!Entry) {
1453         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
1454                           0 /*TODO*/);
1455         Entry = SectionMap.size();
1456       }
1457     }
1458   }
1459   for (const Function &F : M) {
1460     UpdateMaxAlignment(F.getAlign());
1461     if (F.hasSection()) {
1462       // Give section names unique ID's.
1463       unsigned &Entry = SectionMap[std::string(F.getSection())];
1464       if (!Entry) {
1465         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
1466                           0 /*TODO*/);
1467         Entry = SectionMap.size();
1468       }
1469     }
1470     if (F.hasGC()) {
1471       // Same for GC names.
1472       unsigned &Entry = GCMap[F.getGC()];
1473       if (!Entry) {
1474         writeStringRecord(Stream, bitc::MODULE_CODE_GCNAME, F.getGC(),
1475                           0 /*TODO*/);
1476         Entry = GCMap.size();
1477       }
1478     }
1479   }
1480 
1481   // Emit abbrev for globals, now that we know # sections and max alignment.
1482   unsigned SimpleGVarAbbrev = 0;
1483   if (!M.global_empty()) {
1484     // Add an abbrev for common globals with no visibility or thread localness.
1485     auto Abbv = std::make_shared<BitCodeAbbrev>();
1486     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
1487     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1488     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1489     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1490                               Log2_32_Ceil(MaxGlobalType+1)));
1491     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddrSpace << 2
1492                                                            //| explicitType << 1
1493                                                            //| constant
1494     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Initializer.
1495     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // Linkage.
1496     if (!MaxAlignment)                                     // Alignment.
1497       Abbv->Add(BitCodeAbbrevOp(0));
1498     else {
1499       unsigned MaxEncAlignment = getEncodedAlign(MaxAlignment);
1500       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1501                                Log2_32_Ceil(MaxEncAlignment+1)));
1502     }
1503     if (SectionMap.empty())                                    // Section.
1504       Abbv->Add(BitCodeAbbrevOp(0));
1505     else
1506       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1507                                Log2_32_Ceil(SectionMap.size()+1)));
1508     // Don't bother emitting vis + thread local.
1509     SimpleGVarAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1510   }
1511 
1512   SmallVector<unsigned, 64> Vals;
1513   // Emit the module's source file name.
1514   {
1515     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
1516     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
1517     if (Bits == SE_Char6)
1518       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
1519     else if (Bits == SE_Fixed7)
1520       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
1521 
1522     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
1523     auto Abbv = std::make_shared<BitCodeAbbrev>();
1524     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
1525     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1526     Abbv->Add(AbbrevOpToUse);
1527     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1528 
1529     for (const auto P : M.getSourceFileName())
1530       Vals.push_back((unsigned char)P);
1531 
1532     // Emit the finished record.
1533     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
1534     Vals.clear();
1535   }
1536 
1537   // Emit the global variable information.
1538   for (const GlobalVariable &GV : M.globals()) {
1539     unsigned AbbrevToUse = 0;
1540 
1541     // GLOBALVAR: [strtab offset, strtab size, type, isconst, initid,
1542     //             linkage, alignment, section, visibility, threadlocal,
1543     //             unnamed_addr, externally_initialized, dllstorageclass,
1544     //             comdat, attributes, DSO_Local, GlobalSanitizer, code_model]
1545     Vals.push_back(addToStrtab(GV.getName()));
1546     Vals.push_back(GV.getName().size());
1547     Vals.push_back(VE.getTypeID(GV.getValueType()));
1548     Vals.push_back(GV.getType()->getAddressSpace() << 2 | 2 | GV.isConstant());
1549     Vals.push_back(GV.isDeclaration() ? 0 :
1550                    (VE.getValueID(GV.getInitializer()) + 1));
1551     Vals.push_back(getEncodedLinkage(GV));
1552     Vals.push_back(getEncodedAlign(GV.getAlign()));
1553     Vals.push_back(GV.hasSection() ? SectionMap[std::string(GV.getSection())]
1554                                    : 0);
1555     if (GV.isThreadLocal() ||
1556         GV.getVisibility() != GlobalValue::DefaultVisibility ||
1557         GV.getUnnamedAddr() != GlobalValue::UnnamedAddr::None ||
1558         GV.isExternallyInitialized() ||
1559         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
1560         GV.hasComdat() || GV.hasAttributes() || GV.isDSOLocal() ||
1561         GV.hasPartition() || GV.hasSanitizerMetadata() || GV.getCodeModel()) {
1562       Vals.push_back(getEncodedVisibility(GV));
1563       Vals.push_back(getEncodedThreadLocalMode(GV));
1564       Vals.push_back(getEncodedUnnamedAddr(GV));
1565       Vals.push_back(GV.isExternallyInitialized());
1566       Vals.push_back(getEncodedDLLStorageClass(GV));
1567       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
1568 
1569       auto AL = GV.getAttributesAsList(AttributeList::FunctionIndex);
1570       Vals.push_back(VE.getAttributeListID(AL));
1571 
1572       Vals.push_back(GV.isDSOLocal());
1573       Vals.push_back(addToStrtab(GV.getPartition()));
1574       Vals.push_back(GV.getPartition().size());
1575 
1576       Vals.push_back((GV.hasSanitizerMetadata() ? serializeSanitizerMetadata(
1577                                                       GV.getSanitizerMetadata())
1578                                                 : 0));
1579       Vals.push_back(GV.getCodeModelRaw());
1580     } else {
1581       AbbrevToUse = SimpleGVarAbbrev;
1582     }
1583 
1584     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
1585     Vals.clear();
1586   }
1587 
1588   // Emit the function proto information.
1589   for (const Function &F : M) {
1590     // FUNCTION:  [strtab offset, strtab size, type, callingconv, isproto,
1591     //             linkage, paramattrs, alignment, section, visibility, gc,
1592     //             unnamed_addr, prologuedata, dllstorageclass, comdat,
1593     //             prefixdata, personalityfn, DSO_Local, addrspace]
1594     Vals.push_back(addToStrtab(F.getName()));
1595     Vals.push_back(F.getName().size());
1596     Vals.push_back(VE.getTypeID(F.getFunctionType()));
1597     Vals.push_back(F.getCallingConv());
1598     Vals.push_back(F.isDeclaration());
1599     Vals.push_back(getEncodedLinkage(F));
1600     Vals.push_back(VE.getAttributeListID(F.getAttributes()));
1601     Vals.push_back(getEncodedAlign(F.getAlign()));
1602     Vals.push_back(F.hasSection() ? SectionMap[std::string(F.getSection())]
1603                                   : 0);
1604     Vals.push_back(getEncodedVisibility(F));
1605     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
1606     Vals.push_back(getEncodedUnnamedAddr(F));
1607     Vals.push_back(F.hasPrologueData() ? (VE.getValueID(F.getPrologueData()) + 1)
1608                                        : 0);
1609     Vals.push_back(getEncodedDLLStorageClass(F));
1610     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
1611     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
1612                                      : 0);
1613     Vals.push_back(
1614         F.hasPersonalityFn() ? (VE.getValueID(F.getPersonalityFn()) + 1) : 0);
1615 
1616     Vals.push_back(F.isDSOLocal());
1617     Vals.push_back(F.getAddressSpace());
1618     Vals.push_back(addToStrtab(F.getPartition()));
1619     Vals.push_back(F.getPartition().size());
1620 
1621     unsigned AbbrevToUse = 0;
1622     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
1623     Vals.clear();
1624   }
1625 
1626   // Emit the alias information.
1627   for (const GlobalAlias &A : M.aliases()) {
1628     // ALIAS: [strtab offset, strtab size, alias type, aliasee val#, linkage,
1629     //         visibility, dllstorageclass, threadlocal, unnamed_addr,
1630     //         DSO_Local]
1631     Vals.push_back(addToStrtab(A.getName()));
1632     Vals.push_back(A.getName().size());
1633     Vals.push_back(VE.getTypeID(A.getValueType()));
1634     Vals.push_back(A.getType()->getAddressSpace());
1635     Vals.push_back(VE.getValueID(A.getAliasee()));
1636     Vals.push_back(getEncodedLinkage(A));
1637     Vals.push_back(getEncodedVisibility(A));
1638     Vals.push_back(getEncodedDLLStorageClass(A));
1639     Vals.push_back(getEncodedThreadLocalMode(A));
1640     Vals.push_back(getEncodedUnnamedAddr(A));
1641     Vals.push_back(A.isDSOLocal());
1642     Vals.push_back(addToStrtab(A.getPartition()));
1643     Vals.push_back(A.getPartition().size());
1644 
1645     unsigned AbbrevToUse = 0;
1646     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
1647     Vals.clear();
1648   }
1649 
1650   // Emit the ifunc information.
1651   for (const GlobalIFunc &I : M.ifuncs()) {
1652     // IFUNC: [strtab offset, strtab size, ifunc type, address space, resolver
1653     //         val#, linkage, visibility, DSO_Local]
1654     Vals.push_back(addToStrtab(I.getName()));
1655     Vals.push_back(I.getName().size());
1656     Vals.push_back(VE.getTypeID(I.getValueType()));
1657     Vals.push_back(I.getType()->getAddressSpace());
1658     Vals.push_back(VE.getValueID(I.getResolver()));
1659     Vals.push_back(getEncodedLinkage(I));
1660     Vals.push_back(getEncodedVisibility(I));
1661     Vals.push_back(I.isDSOLocal());
1662     Vals.push_back(addToStrtab(I.getPartition()));
1663     Vals.push_back(I.getPartition().size());
1664     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
1665     Vals.clear();
1666   }
1667 
1668   writeValueSymbolTableForwardDecl();
1669 }
1670 
1671 static uint64_t getOptimizationFlags(const Value *V) {
1672   uint64_t Flags = 0;
1673 
1674   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
1675     if (OBO->hasNoSignedWrap())
1676       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
1677     if (OBO->hasNoUnsignedWrap())
1678       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
1679   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
1680     if (PEO->isExact())
1681       Flags |= 1 << bitc::PEO_EXACT;
1682   } else if (const auto *PDI = dyn_cast<PossiblyDisjointInst>(V)) {
1683     if (PDI->isDisjoint())
1684       Flags |= 1 << bitc::PDI_DISJOINT;
1685   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
1686     if (FPMO->hasAllowReassoc())
1687       Flags |= bitc::AllowReassoc;
1688     if (FPMO->hasNoNaNs())
1689       Flags |= bitc::NoNaNs;
1690     if (FPMO->hasNoInfs())
1691       Flags |= bitc::NoInfs;
1692     if (FPMO->hasNoSignedZeros())
1693       Flags |= bitc::NoSignedZeros;
1694     if (FPMO->hasAllowReciprocal())
1695       Flags |= bitc::AllowReciprocal;
1696     if (FPMO->hasAllowContract())
1697       Flags |= bitc::AllowContract;
1698     if (FPMO->hasApproxFunc())
1699       Flags |= bitc::ApproxFunc;
1700   } else if (const auto *NNI = dyn_cast<PossiblyNonNegInst>(V)) {
1701     if (NNI->hasNonNeg())
1702       Flags |= 1 << bitc::PNNI_NON_NEG;
1703   } else if (const auto *TI = dyn_cast<TruncInst>(V)) {
1704     if (TI->hasNoSignedWrap())
1705       Flags |= 1 << bitc::TIO_NO_SIGNED_WRAP;
1706     if (TI->hasNoUnsignedWrap())
1707       Flags |= 1 << bitc::TIO_NO_UNSIGNED_WRAP;
1708   } else if (const auto *GEP = dyn_cast<GEPOperator>(V)) {
1709     if (GEP->isInBounds())
1710       Flags |= 1 << bitc::GEP_INBOUNDS;
1711     if (GEP->hasNoUnsignedSignedWrap())
1712       Flags |= 1 << bitc::GEP_NUSW;
1713     if (GEP->hasNoUnsignedWrap())
1714       Flags |= 1 << bitc::GEP_NUW;
1715   }
1716 
1717   return Flags;
1718 }
1719 
1720 void ModuleBitcodeWriter::writeValueAsMetadata(
1721     const ValueAsMetadata *MD, SmallVectorImpl<uint64_t> &Record) {
1722   // Mimic an MDNode with a value as one operand.
1723   Value *V = MD->getValue();
1724   Record.push_back(VE.getTypeID(V->getType()));
1725   Record.push_back(VE.getValueID(V));
1726   Stream.EmitRecord(bitc::METADATA_VALUE, Record, 0);
1727   Record.clear();
1728 }
1729 
1730 void ModuleBitcodeWriter::writeMDTuple(const MDTuple *N,
1731                                        SmallVectorImpl<uint64_t> &Record,
1732                                        unsigned Abbrev) {
1733   for (const MDOperand &MDO : N->operands()) {
1734     Metadata *MD = MDO;
1735     assert(!(MD && isa<LocalAsMetadata>(MD)) &&
1736            "Unexpected function-local metadata");
1737     Record.push_back(VE.getMetadataOrNullID(MD));
1738   }
1739   Stream.EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
1740                                     : bitc::METADATA_NODE,
1741                     Record, Abbrev);
1742   Record.clear();
1743 }
1744 
1745 unsigned ModuleBitcodeWriter::createDILocationAbbrev() {
1746   // Assume the column is usually under 128, and always output the inlined-at
1747   // location (it's never more expensive than building an array size 1).
1748   auto Abbv = std::make_shared<BitCodeAbbrev>();
1749   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
1750   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1751   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1752   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1753   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1754   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1755   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1756   return Stream.EmitAbbrev(std::move(Abbv));
1757 }
1758 
1759 void ModuleBitcodeWriter::writeDILocation(const DILocation *N,
1760                                           SmallVectorImpl<uint64_t> &Record,
1761                                           unsigned &Abbrev) {
1762   if (!Abbrev)
1763     Abbrev = createDILocationAbbrev();
1764 
1765   Record.push_back(N->isDistinct());
1766   Record.push_back(N->getLine());
1767   Record.push_back(N->getColumn());
1768   Record.push_back(VE.getMetadataID(N->getScope()));
1769   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
1770   Record.push_back(N->isImplicitCode());
1771 
1772   Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
1773   Record.clear();
1774 }
1775 
1776 unsigned ModuleBitcodeWriter::createGenericDINodeAbbrev() {
1777   // Assume the column is usually under 128, and always output the inlined-at
1778   // location (it's never more expensive than building an array size 1).
1779   auto Abbv = std::make_shared<BitCodeAbbrev>();
1780   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
1781   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1782   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1783   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1784   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1785   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1786   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1787   return Stream.EmitAbbrev(std::move(Abbv));
1788 }
1789 
1790 void ModuleBitcodeWriter::writeGenericDINode(const GenericDINode *N,
1791                                              SmallVectorImpl<uint64_t> &Record,
1792                                              unsigned &Abbrev) {
1793   if (!Abbrev)
1794     Abbrev = createGenericDINodeAbbrev();
1795 
1796   Record.push_back(N->isDistinct());
1797   Record.push_back(N->getTag());
1798   Record.push_back(0); // Per-tag version field; unused for now.
1799 
1800   for (auto &I : N->operands())
1801     Record.push_back(VE.getMetadataOrNullID(I));
1802 
1803   Stream.EmitRecord(bitc::METADATA_GENERIC_DEBUG, Record, Abbrev);
1804   Record.clear();
1805 }
1806 
1807 void ModuleBitcodeWriter::writeDISubrange(const DISubrange *N,
1808                                           SmallVectorImpl<uint64_t> &Record,
1809                                           unsigned Abbrev) {
1810   const uint64_t Version = 2 << 1;
1811   Record.push_back((uint64_t)N->isDistinct() | Version);
1812   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1813   Record.push_back(VE.getMetadataOrNullID(N->getRawLowerBound()));
1814   Record.push_back(VE.getMetadataOrNullID(N->getRawUpperBound()));
1815   Record.push_back(VE.getMetadataOrNullID(N->getRawStride()));
1816 
1817   Stream.EmitRecord(bitc::METADATA_SUBRANGE, Record, Abbrev);
1818   Record.clear();
1819 }
1820 
1821 void ModuleBitcodeWriter::writeDIGenericSubrange(
1822     const DIGenericSubrange *N, SmallVectorImpl<uint64_t> &Record,
1823     unsigned Abbrev) {
1824   Record.push_back((uint64_t)N->isDistinct());
1825   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1826   Record.push_back(VE.getMetadataOrNullID(N->getRawLowerBound()));
1827   Record.push_back(VE.getMetadataOrNullID(N->getRawUpperBound()));
1828   Record.push_back(VE.getMetadataOrNullID(N->getRawStride()));
1829 
1830   Stream.EmitRecord(bitc::METADATA_GENERIC_SUBRANGE, Record, Abbrev);
1831   Record.clear();
1832 }
1833 
1834 void ModuleBitcodeWriter::writeDIEnumerator(const DIEnumerator *N,
1835                                             SmallVectorImpl<uint64_t> &Record,
1836                                             unsigned Abbrev) {
1837   const uint64_t IsBigInt = 1 << 2;
1838   Record.push_back(IsBigInt | (N->isUnsigned() << 1) | N->isDistinct());
1839   Record.push_back(N->getValue().getBitWidth());
1840   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1841   emitWideAPInt(Record, N->getValue());
1842 
1843   Stream.EmitRecord(bitc::METADATA_ENUMERATOR, Record, Abbrev);
1844   Record.clear();
1845 }
1846 
1847 void ModuleBitcodeWriter::writeDIBasicType(const DIBasicType *N,
1848                                            SmallVectorImpl<uint64_t> &Record,
1849                                            unsigned Abbrev) {
1850   Record.push_back(N->isDistinct());
1851   Record.push_back(N->getTag());
1852   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1853   Record.push_back(N->getSizeInBits());
1854   Record.push_back(N->getAlignInBits());
1855   Record.push_back(N->getEncoding());
1856   Record.push_back(N->getFlags());
1857 
1858   Stream.EmitRecord(bitc::METADATA_BASIC_TYPE, Record, Abbrev);
1859   Record.clear();
1860 }
1861 
1862 void ModuleBitcodeWriter::writeDIStringType(const DIStringType *N,
1863                                             SmallVectorImpl<uint64_t> &Record,
1864                                             unsigned Abbrev) {
1865   Record.push_back(N->isDistinct());
1866   Record.push_back(N->getTag());
1867   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1868   Record.push_back(VE.getMetadataOrNullID(N->getStringLength()));
1869   Record.push_back(VE.getMetadataOrNullID(N->getStringLengthExp()));
1870   Record.push_back(VE.getMetadataOrNullID(N->getStringLocationExp()));
1871   Record.push_back(N->getSizeInBits());
1872   Record.push_back(N->getAlignInBits());
1873   Record.push_back(N->getEncoding());
1874 
1875   Stream.EmitRecord(bitc::METADATA_STRING_TYPE, Record, Abbrev);
1876   Record.clear();
1877 }
1878 
1879 void ModuleBitcodeWriter::writeDIDerivedType(const DIDerivedType *N,
1880                                              SmallVectorImpl<uint64_t> &Record,
1881                                              unsigned Abbrev) {
1882   Record.push_back(N->isDistinct());
1883   Record.push_back(N->getTag());
1884   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1885   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1886   Record.push_back(N->getLine());
1887   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1888   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1889   Record.push_back(N->getSizeInBits());
1890   Record.push_back(N->getAlignInBits());
1891   Record.push_back(N->getOffsetInBits());
1892   Record.push_back(N->getFlags());
1893   Record.push_back(VE.getMetadataOrNullID(N->getExtraData()));
1894 
1895   // DWARF address space is encoded as N->getDWARFAddressSpace() + 1. 0 means
1896   // that there is no DWARF address space associated with DIDerivedType.
1897   if (const auto &DWARFAddressSpace = N->getDWARFAddressSpace())
1898     Record.push_back(*DWARFAddressSpace + 1);
1899   else
1900     Record.push_back(0);
1901 
1902   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1903 
1904   if (auto PtrAuthData = N->getPtrAuthData())
1905     Record.push_back(PtrAuthData->RawData);
1906   else
1907     Record.push_back(0);
1908 
1909   Stream.EmitRecord(bitc::METADATA_DERIVED_TYPE, Record, Abbrev);
1910   Record.clear();
1911 }
1912 
1913 void ModuleBitcodeWriter::writeDICompositeType(
1914     const DICompositeType *N, SmallVectorImpl<uint64_t> &Record,
1915     unsigned Abbrev) {
1916   const unsigned IsNotUsedInOldTypeRef = 0x2;
1917   Record.push_back(IsNotUsedInOldTypeRef | (unsigned)N->isDistinct());
1918   Record.push_back(N->getTag());
1919   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1920   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1921   Record.push_back(N->getLine());
1922   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1923   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1924   Record.push_back(N->getSizeInBits());
1925   Record.push_back(N->getAlignInBits());
1926   Record.push_back(N->getOffsetInBits());
1927   Record.push_back(N->getFlags());
1928   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1929   Record.push_back(N->getRuntimeLang());
1930   Record.push_back(VE.getMetadataOrNullID(N->getVTableHolder()));
1931   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1932   Record.push_back(VE.getMetadataOrNullID(N->getRawIdentifier()));
1933   Record.push_back(VE.getMetadataOrNullID(N->getDiscriminator()));
1934   Record.push_back(VE.getMetadataOrNullID(N->getRawDataLocation()));
1935   Record.push_back(VE.getMetadataOrNullID(N->getRawAssociated()));
1936   Record.push_back(VE.getMetadataOrNullID(N->getRawAllocated()));
1937   Record.push_back(VE.getMetadataOrNullID(N->getRawRank()));
1938   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1939 
1940   Stream.EmitRecord(bitc::METADATA_COMPOSITE_TYPE, Record, Abbrev);
1941   Record.clear();
1942 }
1943 
1944 void ModuleBitcodeWriter::writeDISubroutineType(
1945     const DISubroutineType *N, SmallVectorImpl<uint64_t> &Record,
1946     unsigned Abbrev) {
1947   const unsigned HasNoOldTypeRefs = 0x2;
1948   Record.push_back(HasNoOldTypeRefs | (unsigned)N->isDistinct());
1949   Record.push_back(N->getFlags());
1950   Record.push_back(VE.getMetadataOrNullID(N->getTypeArray().get()));
1951   Record.push_back(N->getCC());
1952 
1953   Stream.EmitRecord(bitc::METADATA_SUBROUTINE_TYPE, Record, Abbrev);
1954   Record.clear();
1955 }
1956 
1957 void ModuleBitcodeWriter::writeDIFile(const DIFile *N,
1958                                       SmallVectorImpl<uint64_t> &Record,
1959                                       unsigned Abbrev) {
1960   Record.push_back(N->isDistinct());
1961   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
1962   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
1963   if (N->getRawChecksum()) {
1964     Record.push_back(N->getRawChecksum()->Kind);
1965     Record.push_back(VE.getMetadataOrNullID(N->getRawChecksum()->Value));
1966   } else {
1967     // Maintain backwards compatibility with the old internal representation of
1968     // CSK_None in ChecksumKind by writing nulls here when Checksum is None.
1969     Record.push_back(0);
1970     Record.push_back(VE.getMetadataOrNullID(nullptr));
1971   }
1972   auto Source = N->getRawSource();
1973   if (Source)
1974     Record.push_back(VE.getMetadataOrNullID(Source));
1975 
1976   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
1977   Record.clear();
1978 }
1979 
1980 void ModuleBitcodeWriter::writeDICompileUnit(const DICompileUnit *N,
1981                                              SmallVectorImpl<uint64_t> &Record,
1982                                              unsigned Abbrev) {
1983   assert(N->isDistinct() && "Expected distinct compile units");
1984   Record.push_back(/* IsDistinct */ true);
1985   Record.push_back(N->getSourceLanguage());
1986   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1987   Record.push_back(VE.getMetadataOrNullID(N->getRawProducer()));
1988   Record.push_back(N->isOptimized());
1989   Record.push_back(VE.getMetadataOrNullID(N->getRawFlags()));
1990   Record.push_back(N->getRuntimeVersion());
1991   Record.push_back(VE.getMetadataOrNullID(N->getRawSplitDebugFilename()));
1992   Record.push_back(N->getEmissionKind());
1993   Record.push_back(VE.getMetadataOrNullID(N->getEnumTypes().get()));
1994   Record.push_back(VE.getMetadataOrNullID(N->getRetainedTypes().get()));
1995   Record.push_back(/* subprograms */ 0);
1996   Record.push_back(VE.getMetadataOrNullID(N->getGlobalVariables().get()));
1997   Record.push_back(VE.getMetadataOrNullID(N->getImportedEntities().get()));
1998   Record.push_back(N->getDWOId());
1999   Record.push_back(VE.getMetadataOrNullID(N->getMacros().get()));
2000   Record.push_back(N->getSplitDebugInlining());
2001   Record.push_back(N->getDebugInfoForProfiling());
2002   Record.push_back((unsigned)N->getNameTableKind());
2003   Record.push_back(N->getRangesBaseAddress());
2004   Record.push_back(VE.getMetadataOrNullID(N->getRawSysRoot()));
2005   Record.push_back(VE.getMetadataOrNullID(N->getRawSDK()));
2006 
2007   Stream.EmitRecord(bitc::METADATA_COMPILE_UNIT, Record, Abbrev);
2008   Record.clear();
2009 }
2010 
2011 void ModuleBitcodeWriter::writeDISubprogram(const DISubprogram *N,
2012                                             SmallVectorImpl<uint64_t> &Record,
2013                                             unsigned Abbrev) {
2014   const uint64_t HasUnitFlag = 1 << 1;
2015   const uint64_t HasSPFlagsFlag = 1 << 2;
2016   Record.push_back(uint64_t(N->isDistinct()) | HasUnitFlag | HasSPFlagsFlag);
2017   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2018   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2019   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
2020   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2021   Record.push_back(N->getLine());
2022   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2023   Record.push_back(N->getScopeLine());
2024   Record.push_back(VE.getMetadataOrNullID(N->getContainingType()));
2025   Record.push_back(N->getSPFlags());
2026   Record.push_back(N->getVirtualIndex());
2027   Record.push_back(N->getFlags());
2028   Record.push_back(VE.getMetadataOrNullID(N->getRawUnit()));
2029   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
2030   Record.push_back(VE.getMetadataOrNullID(N->getDeclaration()));
2031   Record.push_back(VE.getMetadataOrNullID(N->getRetainedNodes().get()));
2032   Record.push_back(N->getThisAdjustment());
2033   Record.push_back(VE.getMetadataOrNullID(N->getThrownTypes().get()));
2034   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
2035   Record.push_back(VE.getMetadataOrNullID(N->getRawTargetFuncName()));
2036 
2037   Stream.EmitRecord(bitc::METADATA_SUBPROGRAM, Record, Abbrev);
2038   Record.clear();
2039 }
2040 
2041 void ModuleBitcodeWriter::writeDILexicalBlock(const DILexicalBlock *N,
2042                                               SmallVectorImpl<uint64_t> &Record,
2043                                               unsigned Abbrev) {
2044   Record.push_back(N->isDistinct());
2045   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2046   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2047   Record.push_back(N->getLine());
2048   Record.push_back(N->getColumn());
2049 
2050   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK, Record, Abbrev);
2051   Record.clear();
2052 }
2053 
2054 void ModuleBitcodeWriter::writeDILexicalBlockFile(
2055     const DILexicalBlockFile *N, SmallVectorImpl<uint64_t> &Record,
2056     unsigned Abbrev) {
2057   Record.push_back(N->isDistinct());
2058   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2059   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2060   Record.push_back(N->getDiscriminator());
2061 
2062   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK_FILE, Record, Abbrev);
2063   Record.clear();
2064 }
2065 
2066 void ModuleBitcodeWriter::writeDICommonBlock(const DICommonBlock *N,
2067                                              SmallVectorImpl<uint64_t> &Record,
2068                                              unsigned Abbrev) {
2069   Record.push_back(N->isDistinct());
2070   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2071   Record.push_back(VE.getMetadataOrNullID(N->getDecl()));
2072   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2073   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2074   Record.push_back(N->getLineNo());
2075 
2076   Stream.EmitRecord(bitc::METADATA_COMMON_BLOCK, Record, Abbrev);
2077   Record.clear();
2078 }
2079 
2080 void ModuleBitcodeWriter::writeDINamespace(const DINamespace *N,
2081                                            SmallVectorImpl<uint64_t> &Record,
2082                                            unsigned Abbrev) {
2083   Record.push_back(N->isDistinct() | N->getExportSymbols() << 1);
2084   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2085   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2086 
2087   Stream.EmitRecord(bitc::METADATA_NAMESPACE, Record, Abbrev);
2088   Record.clear();
2089 }
2090 
2091 void ModuleBitcodeWriter::writeDIMacro(const DIMacro *N,
2092                                        SmallVectorImpl<uint64_t> &Record,
2093                                        unsigned Abbrev) {
2094   Record.push_back(N->isDistinct());
2095   Record.push_back(N->getMacinfoType());
2096   Record.push_back(N->getLine());
2097   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2098   Record.push_back(VE.getMetadataOrNullID(N->getRawValue()));
2099 
2100   Stream.EmitRecord(bitc::METADATA_MACRO, Record, Abbrev);
2101   Record.clear();
2102 }
2103 
2104 void ModuleBitcodeWriter::writeDIMacroFile(const DIMacroFile *N,
2105                                            SmallVectorImpl<uint64_t> &Record,
2106                                            unsigned Abbrev) {
2107   Record.push_back(N->isDistinct());
2108   Record.push_back(N->getMacinfoType());
2109   Record.push_back(N->getLine());
2110   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2111   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
2112 
2113   Stream.EmitRecord(bitc::METADATA_MACRO_FILE, Record, Abbrev);
2114   Record.clear();
2115 }
2116 
2117 void ModuleBitcodeWriter::writeDIArgList(const DIArgList *N,
2118                                          SmallVectorImpl<uint64_t> &Record) {
2119   Record.reserve(N->getArgs().size());
2120   for (ValueAsMetadata *MD : N->getArgs())
2121     Record.push_back(VE.getMetadataID(MD));
2122 
2123   Stream.EmitRecord(bitc::METADATA_ARG_LIST, Record);
2124   Record.clear();
2125 }
2126 
2127 void ModuleBitcodeWriter::writeDIModule(const DIModule *N,
2128                                         SmallVectorImpl<uint64_t> &Record,
2129                                         unsigned Abbrev) {
2130   Record.push_back(N->isDistinct());
2131   for (auto &I : N->operands())
2132     Record.push_back(VE.getMetadataOrNullID(I));
2133   Record.push_back(N->getLineNo());
2134   Record.push_back(N->getIsDecl());
2135 
2136   Stream.EmitRecord(bitc::METADATA_MODULE, Record, Abbrev);
2137   Record.clear();
2138 }
2139 
2140 void ModuleBitcodeWriter::writeDIAssignID(const DIAssignID *N,
2141                                           SmallVectorImpl<uint64_t> &Record,
2142                                           unsigned Abbrev) {
2143   // There are no arguments for this metadata type.
2144   Record.push_back(N->isDistinct());
2145   Stream.EmitRecord(bitc::METADATA_ASSIGN_ID, Record, Abbrev);
2146   Record.clear();
2147 }
2148 
2149 void ModuleBitcodeWriter::writeDITemplateTypeParameter(
2150     const DITemplateTypeParameter *N, SmallVectorImpl<uint64_t> &Record,
2151     unsigned Abbrev) {
2152   Record.push_back(N->isDistinct());
2153   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2154   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2155   Record.push_back(N->isDefault());
2156 
2157   Stream.EmitRecord(bitc::METADATA_TEMPLATE_TYPE, Record, Abbrev);
2158   Record.clear();
2159 }
2160 
2161 void ModuleBitcodeWriter::writeDITemplateValueParameter(
2162     const DITemplateValueParameter *N, SmallVectorImpl<uint64_t> &Record,
2163     unsigned Abbrev) {
2164   Record.push_back(N->isDistinct());
2165   Record.push_back(N->getTag());
2166   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2167   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2168   Record.push_back(N->isDefault());
2169   Record.push_back(VE.getMetadataOrNullID(N->getValue()));
2170 
2171   Stream.EmitRecord(bitc::METADATA_TEMPLATE_VALUE, Record, Abbrev);
2172   Record.clear();
2173 }
2174 
2175 void ModuleBitcodeWriter::writeDIGlobalVariable(
2176     const DIGlobalVariable *N, SmallVectorImpl<uint64_t> &Record,
2177     unsigned Abbrev) {
2178   const uint64_t Version = 2 << 1;
2179   Record.push_back((uint64_t)N->isDistinct() | Version);
2180   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2181   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2182   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
2183   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2184   Record.push_back(N->getLine());
2185   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2186   Record.push_back(N->isLocalToUnit());
2187   Record.push_back(N->isDefinition());
2188   Record.push_back(VE.getMetadataOrNullID(N->getStaticDataMemberDeclaration()));
2189   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams()));
2190   Record.push_back(N->getAlignInBits());
2191   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
2192 
2193   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR, Record, Abbrev);
2194   Record.clear();
2195 }
2196 
2197 void ModuleBitcodeWriter::writeDILocalVariable(
2198     const DILocalVariable *N, SmallVectorImpl<uint64_t> &Record,
2199     unsigned Abbrev) {
2200   // In order to support all possible bitcode formats in BitcodeReader we need
2201   // to distinguish the following cases:
2202   // 1) Record has no artificial tag (Record[1]),
2203   //   has no obsolete inlinedAt field (Record[9]).
2204   //   In this case Record size will be 8, HasAlignment flag is false.
2205   // 2) Record has artificial tag (Record[1]),
2206   //   has no obsolete inlignedAt field (Record[9]).
2207   //   In this case Record size will be 9, HasAlignment flag is false.
2208   // 3) Record has both artificial tag (Record[1]) and
2209   //   obsolete inlignedAt field (Record[9]).
2210   //   In this case Record size will be 10, HasAlignment flag is false.
2211   // 4) Record has neither artificial tag, nor inlignedAt field, but
2212   //   HasAlignment flag is true and Record[8] contains alignment value.
2213   const uint64_t HasAlignmentFlag = 1 << 1;
2214   Record.push_back((uint64_t)N->isDistinct() | HasAlignmentFlag);
2215   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2216   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2217   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2218   Record.push_back(N->getLine());
2219   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2220   Record.push_back(N->getArg());
2221   Record.push_back(N->getFlags());
2222   Record.push_back(N->getAlignInBits());
2223   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
2224 
2225   Stream.EmitRecord(bitc::METADATA_LOCAL_VAR, Record, Abbrev);
2226   Record.clear();
2227 }
2228 
2229 void ModuleBitcodeWriter::writeDILabel(
2230     const DILabel *N, SmallVectorImpl<uint64_t> &Record,
2231     unsigned Abbrev) {
2232   Record.push_back((uint64_t)N->isDistinct());
2233   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2234   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2235   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2236   Record.push_back(N->getLine());
2237 
2238   Stream.EmitRecord(bitc::METADATA_LABEL, Record, Abbrev);
2239   Record.clear();
2240 }
2241 
2242 void ModuleBitcodeWriter::writeDIExpression(const DIExpression *N,
2243                                             SmallVectorImpl<uint64_t> &Record,
2244                                             unsigned Abbrev) {
2245   Record.reserve(N->getElements().size() + 1);
2246   const uint64_t Version = 3 << 1;
2247   Record.push_back((uint64_t)N->isDistinct() | Version);
2248   Record.append(N->elements_begin(), N->elements_end());
2249 
2250   Stream.EmitRecord(bitc::METADATA_EXPRESSION, Record, Abbrev);
2251   Record.clear();
2252 }
2253 
2254 void ModuleBitcodeWriter::writeDIGlobalVariableExpression(
2255     const DIGlobalVariableExpression *N, SmallVectorImpl<uint64_t> &Record,
2256     unsigned Abbrev) {
2257   Record.push_back(N->isDistinct());
2258   Record.push_back(VE.getMetadataOrNullID(N->getVariable()));
2259   Record.push_back(VE.getMetadataOrNullID(N->getExpression()));
2260 
2261   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR_EXPR, Record, Abbrev);
2262   Record.clear();
2263 }
2264 
2265 void ModuleBitcodeWriter::writeDIObjCProperty(const DIObjCProperty *N,
2266                                               SmallVectorImpl<uint64_t> &Record,
2267                                               unsigned Abbrev) {
2268   Record.push_back(N->isDistinct());
2269   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2270   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2271   Record.push_back(N->getLine());
2272   Record.push_back(VE.getMetadataOrNullID(N->getRawSetterName()));
2273   Record.push_back(VE.getMetadataOrNullID(N->getRawGetterName()));
2274   Record.push_back(N->getAttributes());
2275   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2276 
2277   Stream.EmitRecord(bitc::METADATA_OBJC_PROPERTY, Record, Abbrev);
2278   Record.clear();
2279 }
2280 
2281 void ModuleBitcodeWriter::writeDIImportedEntity(
2282     const DIImportedEntity *N, SmallVectorImpl<uint64_t> &Record,
2283     unsigned Abbrev) {
2284   Record.push_back(N->isDistinct());
2285   Record.push_back(N->getTag());
2286   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2287   Record.push_back(VE.getMetadataOrNullID(N->getEntity()));
2288   Record.push_back(N->getLine());
2289   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2290   Record.push_back(VE.getMetadataOrNullID(N->getRawFile()));
2291   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
2292 
2293   Stream.EmitRecord(bitc::METADATA_IMPORTED_ENTITY, Record, Abbrev);
2294   Record.clear();
2295 }
2296 
2297 unsigned ModuleBitcodeWriter::createNamedMetadataAbbrev() {
2298   auto Abbv = std::make_shared<BitCodeAbbrev>();
2299   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
2300   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2301   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2302   return Stream.EmitAbbrev(std::move(Abbv));
2303 }
2304 
2305 void ModuleBitcodeWriter::writeNamedMetadata(
2306     SmallVectorImpl<uint64_t> &Record) {
2307   if (M.named_metadata_empty())
2308     return;
2309 
2310   unsigned Abbrev = createNamedMetadataAbbrev();
2311   for (const NamedMDNode &NMD : M.named_metadata()) {
2312     // Write name.
2313     StringRef Str = NMD.getName();
2314     Record.append(Str.bytes_begin(), Str.bytes_end());
2315     Stream.EmitRecord(bitc::METADATA_NAME, Record, Abbrev);
2316     Record.clear();
2317 
2318     // Write named metadata operands.
2319     for (const MDNode *N : NMD.operands())
2320       Record.push_back(VE.getMetadataID(N));
2321     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
2322     Record.clear();
2323   }
2324 }
2325 
2326 unsigned ModuleBitcodeWriter::createMetadataStringsAbbrev() {
2327   auto Abbv = std::make_shared<BitCodeAbbrev>();
2328   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRINGS));
2329   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // # of strings
2330   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // offset to chars
2331   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
2332   return Stream.EmitAbbrev(std::move(Abbv));
2333 }
2334 
2335 /// Write out a record for MDString.
2336 ///
2337 /// All the metadata strings in a metadata block are emitted in a single
2338 /// record.  The sizes and strings themselves are shoved into a blob.
2339 void ModuleBitcodeWriter::writeMetadataStrings(
2340     ArrayRef<const Metadata *> Strings, SmallVectorImpl<uint64_t> &Record) {
2341   if (Strings.empty())
2342     return;
2343 
2344   // Start the record with the number of strings.
2345   Record.push_back(bitc::METADATA_STRINGS);
2346   Record.push_back(Strings.size());
2347 
2348   // Emit the sizes of the strings in the blob.
2349   SmallString<256> Blob;
2350   {
2351     BitstreamWriter W(Blob);
2352     for (const Metadata *MD : Strings)
2353       W.EmitVBR(cast<MDString>(MD)->getLength(), 6);
2354     W.FlushToWord();
2355   }
2356 
2357   // Add the offset to the strings to the record.
2358   Record.push_back(Blob.size());
2359 
2360   // Add the strings to the blob.
2361   for (const Metadata *MD : Strings)
2362     Blob.append(cast<MDString>(MD)->getString());
2363 
2364   // Emit the final record.
2365   Stream.EmitRecordWithBlob(createMetadataStringsAbbrev(), Record, Blob);
2366   Record.clear();
2367 }
2368 
2369 // Generates an enum to use as an index in the Abbrev array of Metadata record.
2370 enum MetadataAbbrev : unsigned {
2371 #define HANDLE_MDNODE_LEAF(CLASS) CLASS##AbbrevID,
2372 #include "llvm/IR/Metadata.def"
2373   LastPlusOne
2374 };
2375 
2376 void ModuleBitcodeWriter::writeMetadataRecords(
2377     ArrayRef<const Metadata *> MDs, SmallVectorImpl<uint64_t> &Record,
2378     std::vector<unsigned> *MDAbbrevs, std::vector<uint64_t> *IndexPos) {
2379   if (MDs.empty())
2380     return;
2381 
2382   // Initialize MDNode abbreviations.
2383 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
2384 #include "llvm/IR/Metadata.def"
2385 
2386   for (const Metadata *MD : MDs) {
2387     if (IndexPos)
2388       IndexPos->push_back(Stream.GetCurrentBitNo());
2389     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
2390       assert(N->isResolved() && "Expected forward references to be resolved");
2391 
2392       switch (N->getMetadataID()) {
2393       default:
2394         llvm_unreachable("Invalid MDNode subclass");
2395 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
2396   case Metadata::CLASS##Kind:                                                  \
2397     if (MDAbbrevs)                                                             \
2398       write##CLASS(cast<CLASS>(N), Record,                                     \
2399                    (*MDAbbrevs)[MetadataAbbrev::CLASS##AbbrevID]);             \
2400     else                                                                       \
2401       write##CLASS(cast<CLASS>(N), Record, CLASS##Abbrev);                     \
2402     continue;
2403 #include "llvm/IR/Metadata.def"
2404       }
2405     }
2406     if (auto *AL = dyn_cast<DIArgList>(MD)) {
2407       writeDIArgList(AL, Record);
2408       continue;
2409     }
2410     writeValueAsMetadata(cast<ValueAsMetadata>(MD), Record);
2411   }
2412 }
2413 
2414 void ModuleBitcodeWriter::writeModuleMetadata() {
2415   if (!VE.hasMDs() && M.named_metadata_empty())
2416     return;
2417 
2418   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 4);
2419   SmallVector<uint64_t, 64> Record;
2420 
2421   // Emit all abbrevs upfront, so that the reader can jump in the middle of the
2422   // block and load any metadata.
2423   std::vector<unsigned> MDAbbrevs;
2424 
2425   MDAbbrevs.resize(MetadataAbbrev::LastPlusOne);
2426   MDAbbrevs[MetadataAbbrev::DILocationAbbrevID] = createDILocationAbbrev();
2427   MDAbbrevs[MetadataAbbrev::GenericDINodeAbbrevID] =
2428       createGenericDINodeAbbrev();
2429 
2430   auto Abbv = std::make_shared<BitCodeAbbrev>();
2431   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX_OFFSET));
2432   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2433   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2434   unsigned OffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2435 
2436   Abbv = std::make_shared<BitCodeAbbrev>();
2437   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX));
2438   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2439   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2440   unsigned IndexAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2441 
2442   // Emit MDStrings together upfront.
2443   writeMetadataStrings(VE.getMDStrings(), Record);
2444 
2445   // We only emit an index for the metadata record if we have more than a given
2446   // (naive) threshold of metadatas, otherwise it is not worth it.
2447   if (VE.getNonMDStrings().size() > IndexThreshold) {
2448     // Write a placeholder value in for the offset of the metadata index,
2449     // which is written after the records, so that it can include
2450     // the offset of each entry. The placeholder offset will be
2451     // updated after all records are emitted.
2452     uint64_t Vals[] = {0, 0};
2453     Stream.EmitRecord(bitc::METADATA_INDEX_OFFSET, Vals, OffsetAbbrev);
2454   }
2455 
2456   // Compute and save the bit offset to the current position, which will be
2457   // patched when we emit the index later. We can simply subtract the 64-bit
2458   // fixed size from the current bit number to get the location to backpatch.
2459   uint64_t IndexOffsetRecordBitPos = Stream.GetCurrentBitNo();
2460 
2461   // This index will contain the bitpos for each individual record.
2462   std::vector<uint64_t> IndexPos;
2463   IndexPos.reserve(VE.getNonMDStrings().size());
2464 
2465   // Write all the records
2466   writeMetadataRecords(VE.getNonMDStrings(), Record, &MDAbbrevs, &IndexPos);
2467 
2468   if (VE.getNonMDStrings().size() > IndexThreshold) {
2469     // Now that we have emitted all the records we will emit the index. But
2470     // first
2471     // backpatch the forward reference so that the reader can skip the records
2472     // efficiently.
2473     Stream.BackpatchWord64(IndexOffsetRecordBitPos - 64,
2474                            Stream.GetCurrentBitNo() - IndexOffsetRecordBitPos);
2475 
2476     // Delta encode the index.
2477     uint64_t PreviousValue = IndexOffsetRecordBitPos;
2478     for (auto &Elt : IndexPos) {
2479       auto EltDelta = Elt - PreviousValue;
2480       PreviousValue = Elt;
2481       Elt = EltDelta;
2482     }
2483     // Emit the index record.
2484     Stream.EmitRecord(bitc::METADATA_INDEX, IndexPos, IndexAbbrev);
2485     IndexPos.clear();
2486   }
2487 
2488   // Write the named metadata now.
2489   writeNamedMetadata(Record);
2490 
2491   auto AddDeclAttachedMetadata = [&](const GlobalObject &GO) {
2492     SmallVector<uint64_t, 4> Record;
2493     Record.push_back(VE.getValueID(&GO));
2494     pushGlobalMetadataAttachment(Record, GO);
2495     Stream.EmitRecord(bitc::METADATA_GLOBAL_DECL_ATTACHMENT, Record);
2496   };
2497   for (const Function &F : M)
2498     if (F.isDeclaration() && F.hasMetadata())
2499       AddDeclAttachedMetadata(F);
2500   // FIXME: Only store metadata for declarations here, and move data for global
2501   // variable definitions to a separate block (PR28134).
2502   for (const GlobalVariable &GV : M.globals())
2503     if (GV.hasMetadata())
2504       AddDeclAttachedMetadata(GV);
2505 
2506   Stream.ExitBlock();
2507 }
2508 
2509 void ModuleBitcodeWriter::writeFunctionMetadata(const Function &F) {
2510   if (!VE.hasMDs())
2511     return;
2512 
2513   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
2514   SmallVector<uint64_t, 64> Record;
2515   writeMetadataStrings(VE.getMDStrings(), Record);
2516   writeMetadataRecords(VE.getNonMDStrings(), Record);
2517   Stream.ExitBlock();
2518 }
2519 
2520 void ModuleBitcodeWriter::pushGlobalMetadataAttachment(
2521     SmallVectorImpl<uint64_t> &Record, const GlobalObject &GO) {
2522   // [n x [id, mdnode]]
2523   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2524   GO.getAllMetadata(MDs);
2525   for (const auto &I : MDs) {
2526     Record.push_back(I.first);
2527     Record.push_back(VE.getMetadataID(I.second));
2528   }
2529 }
2530 
2531 void ModuleBitcodeWriter::writeFunctionMetadataAttachment(const Function &F) {
2532   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
2533 
2534   SmallVector<uint64_t, 64> Record;
2535 
2536   if (F.hasMetadata()) {
2537     pushGlobalMetadataAttachment(Record, F);
2538     Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2539     Record.clear();
2540   }
2541 
2542   // Write metadata attachments
2543   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
2544   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2545   for (const BasicBlock &BB : F)
2546     for (const Instruction &I : BB) {
2547       MDs.clear();
2548       I.getAllMetadataOtherThanDebugLoc(MDs);
2549 
2550       // If no metadata, ignore instruction.
2551       if (MDs.empty()) continue;
2552 
2553       Record.push_back(VE.getInstructionID(&I));
2554 
2555       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
2556         Record.push_back(MDs[i].first);
2557         Record.push_back(VE.getMetadataID(MDs[i].second));
2558       }
2559       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2560       Record.clear();
2561     }
2562 
2563   Stream.ExitBlock();
2564 }
2565 
2566 void ModuleBitcodeWriter::writeModuleMetadataKinds() {
2567   SmallVector<uint64_t, 64> Record;
2568 
2569   // Write metadata kinds
2570   // METADATA_KIND - [n x [id, name]]
2571   SmallVector<StringRef, 8> Names;
2572   M.getMDKindNames(Names);
2573 
2574   if (Names.empty()) return;
2575 
2576   Stream.EnterSubblock(bitc::METADATA_KIND_BLOCK_ID, 3);
2577 
2578   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
2579     Record.push_back(MDKindID);
2580     StringRef KName = Names[MDKindID];
2581     Record.append(KName.begin(), KName.end());
2582 
2583     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
2584     Record.clear();
2585   }
2586 
2587   Stream.ExitBlock();
2588 }
2589 
2590 void ModuleBitcodeWriter::writeOperandBundleTags() {
2591   // Write metadata kinds
2592   //
2593   // OPERAND_BUNDLE_TAGS_BLOCK_ID : N x OPERAND_BUNDLE_TAG
2594   //
2595   // OPERAND_BUNDLE_TAG - [strchr x N]
2596 
2597   SmallVector<StringRef, 8> Tags;
2598   M.getOperandBundleTags(Tags);
2599 
2600   if (Tags.empty())
2601     return;
2602 
2603   Stream.EnterSubblock(bitc::OPERAND_BUNDLE_TAGS_BLOCK_ID, 3);
2604 
2605   SmallVector<uint64_t, 64> Record;
2606 
2607   for (auto Tag : Tags) {
2608     Record.append(Tag.begin(), Tag.end());
2609 
2610     Stream.EmitRecord(bitc::OPERAND_BUNDLE_TAG, Record, 0);
2611     Record.clear();
2612   }
2613 
2614   Stream.ExitBlock();
2615 }
2616 
2617 void ModuleBitcodeWriter::writeSyncScopeNames() {
2618   SmallVector<StringRef, 8> SSNs;
2619   M.getContext().getSyncScopeNames(SSNs);
2620   if (SSNs.empty())
2621     return;
2622 
2623   Stream.EnterSubblock(bitc::SYNC_SCOPE_NAMES_BLOCK_ID, 2);
2624 
2625   SmallVector<uint64_t, 64> Record;
2626   for (auto SSN : SSNs) {
2627     Record.append(SSN.begin(), SSN.end());
2628     Stream.EmitRecord(bitc::SYNC_SCOPE_NAME, Record, 0);
2629     Record.clear();
2630   }
2631 
2632   Stream.ExitBlock();
2633 }
2634 
2635 void ModuleBitcodeWriter::writeConstants(unsigned FirstVal, unsigned LastVal,
2636                                          bool isGlobal) {
2637   if (FirstVal == LastVal) return;
2638 
2639   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
2640 
2641   unsigned AggregateAbbrev = 0;
2642   unsigned String8Abbrev = 0;
2643   unsigned CString7Abbrev = 0;
2644   unsigned CString6Abbrev = 0;
2645   // If this is a constant pool for the module, emit module-specific abbrevs.
2646   if (isGlobal) {
2647     // Abbrev for CST_CODE_AGGREGATE.
2648     auto Abbv = std::make_shared<BitCodeAbbrev>();
2649     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
2650     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2651     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
2652     AggregateAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2653 
2654     // Abbrev for CST_CODE_STRING.
2655     Abbv = std::make_shared<BitCodeAbbrev>();
2656     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
2657     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2658     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2659     String8Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2660     // Abbrev for CST_CODE_CSTRING.
2661     Abbv = std::make_shared<BitCodeAbbrev>();
2662     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2663     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2664     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2665     CString7Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2666     // Abbrev for CST_CODE_CSTRING.
2667     Abbv = std::make_shared<BitCodeAbbrev>();
2668     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2669     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2670     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2671     CString6Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2672   }
2673 
2674   SmallVector<uint64_t, 64> Record;
2675 
2676   const ValueEnumerator::ValueList &Vals = VE.getValues();
2677   Type *LastTy = nullptr;
2678   for (unsigned i = FirstVal; i != LastVal; ++i) {
2679     const Value *V = Vals[i].first;
2680     // If we need to switch types, do so now.
2681     if (V->getType() != LastTy) {
2682       LastTy = V->getType();
2683       Record.push_back(VE.getTypeID(LastTy));
2684       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
2685                         CONSTANTS_SETTYPE_ABBREV);
2686       Record.clear();
2687     }
2688 
2689     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
2690       Record.push_back(VE.getTypeID(IA->getFunctionType()));
2691       Record.push_back(
2692           unsigned(IA->hasSideEffects()) | unsigned(IA->isAlignStack()) << 1 |
2693           unsigned(IA->getDialect() & 1) << 2 | unsigned(IA->canThrow()) << 3);
2694 
2695       // Add the asm string.
2696       const std::string &AsmStr = IA->getAsmString();
2697       Record.push_back(AsmStr.size());
2698       Record.append(AsmStr.begin(), AsmStr.end());
2699 
2700       // Add the constraint string.
2701       const std::string &ConstraintStr = IA->getConstraintString();
2702       Record.push_back(ConstraintStr.size());
2703       Record.append(ConstraintStr.begin(), ConstraintStr.end());
2704       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
2705       Record.clear();
2706       continue;
2707     }
2708     const Constant *C = cast<Constant>(V);
2709     unsigned Code = -1U;
2710     unsigned AbbrevToUse = 0;
2711     if (C->isNullValue()) {
2712       Code = bitc::CST_CODE_NULL;
2713     } else if (isa<PoisonValue>(C)) {
2714       Code = bitc::CST_CODE_POISON;
2715     } else if (isa<UndefValue>(C)) {
2716       Code = bitc::CST_CODE_UNDEF;
2717     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
2718       if (IV->getBitWidth() <= 64) {
2719         uint64_t V = IV->getSExtValue();
2720         emitSignedInt64(Record, V);
2721         Code = bitc::CST_CODE_INTEGER;
2722         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
2723       } else {                             // Wide integers, > 64 bits in size.
2724         emitWideAPInt(Record, IV->getValue());
2725         Code = bitc::CST_CODE_WIDE_INTEGER;
2726       }
2727     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
2728       Code = bitc::CST_CODE_FLOAT;
2729       Type *Ty = CFP->getType()->getScalarType();
2730       if (Ty->isHalfTy() || Ty->isBFloatTy() || Ty->isFloatTy() ||
2731           Ty->isDoubleTy()) {
2732         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
2733       } else if (Ty->isX86_FP80Ty()) {
2734         // api needed to prevent premature destruction
2735         // bits are not in the same order as a normal i80 APInt, compensate.
2736         APInt api = CFP->getValueAPF().bitcastToAPInt();
2737         const uint64_t *p = api.getRawData();
2738         Record.push_back((p[1] << 48) | (p[0] >> 16));
2739         Record.push_back(p[0] & 0xffffLL);
2740       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
2741         APInt api = CFP->getValueAPF().bitcastToAPInt();
2742         const uint64_t *p = api.getRawData();
2743         Record.push_back(p[0]);
2744         Record.push_back(p[1]);
2745       } else {
2746         assert(0 && "Unknown FP type!");
2747       }
2748     } else if (isa<ConstantDataSequential>(C) &&
2749                cast<ConstantDataSequential>(C)->isString()) {
2750       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
2751       // Emit constant strings specially.
2752       unsigned NumElts = Str->getNumElements();
2753       // If this is a null-terminated string, use the denser CSTRING encoding.
2754       if (Str->isCString()) {
2755         Code = bitc::CST_CODE_CSTRING;
2756         --NumElts;  // Don't encode the null, which isn't allowed by char6.
2757       } else {
2758         Code = bitc::CST_CODE_STRING;
2759         AbbrevToUse = String8Abbrev;
2760       }
2761       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
2762       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
2763       for (unsigned i = 0; i != NumElts; ++i) {
2764         unsigned char V = Str->getElementAsInteger(i);
2765         Record.push_back(V);
2766         isCStr7 &= (V & 128) == 0;
2767         if (isCStrChar6)
2768           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
2769       }
2770 
2771       if (isCStrChar6)
2772         AbbrevToUse = CString6Abbrev;
2773       else if (isCStr7)
2774         AbbrevToUse = CString7Abbrev;
2775     } else if (const ConstantDataSequential *CDS =
2776                   dyn_cast<ConstantDataSequential>(C)) {
2777       Code = bitc::CST_CODE_DATA;
2778       Type *EltTy = CDS->getElementType();
2779       if (isa<IntegerType>(EltTy)) {
2780         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2781           Record.push_back(CDS->getElementAsInteger(i));
2782       } else {
2783         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2784           Record.push_back(
2785               CDS->getElementAsAPFloat(i).bitcastToAPInt().getLimitedValue());
2786       }
2787     } else if (isa<ConstantAggregate>(C)) {
2788       Code = bitc::CST_CODE_AGGREGATE;
2789       for (const Value *Op : C->operands())
2790         Record.push_back(VE.getValueID(Op));
2791       AbbrevToUse = AggregateAbbrev;
2792     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
2793       switch (CE->getOpcode()) {
2794       default:
2795         if (Instruction::isCast(CE->getOpcode())) {
2796           Code = bitc::CST_CODE_CE_CAST;
2797           Record.push_back(getEncodedCastOpcode(CE->getOpcode()));
2798           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2799           Record.push_back(VE.getValueID(C->getOperand(0)));
2800           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
2801         } else {
2802           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
2803           Code = bitc::CST_CODE_CE_BINOP;
2804           Record.push_back(getEncodedBinaryOpcode(CE->getOpcode()));
2805           Record.push_back(VE.getValueID(C->getOperand(0)));
2806           Record.push_back(VE.getValueID(C->getOperand(1)));
2807           uint64_t Flags = getOptimizationFlags(CE);
2808           if (Flags != 0)
2809             Record.push_back(Flags);
2810         }
2811         break;
2812       case Instruction::FNeg: {
2813         assert(CE->getNumOperands() == 1 && "Unknown constant expr!");
2814         Code = bitc::CST_CODE_CE_UNOP;
2815         Record.push_back(getEncodedUnaryOpcode(CE->getOpcode()));
2816         Record.push_back(VE.getValueID(C->getOperand(0)));
2817         uint64_t Flags = getOptimizationFlags(CE);
2818         if (Flags != 0)
2819           Record.push_back(Flags);
2820         break;
2821       }
2822       case Instruction::GetElementPtr: {
2823         Code = bitc::CST_CODE_CE_GEP;
2824         const auto *GO = cast<GEPOperator>(C);
2825         Record.push_back(VE.getTypeID(GO->getSourceElementType()));
2826         Record.push_back(getOptimizationFlags(GO));
2827         if (std::optional<ConstantRange> Range = GO->getInRange()) {
2828           Code = bitc::CST_CODE_CE_GEP_WITH_INRANGE;
2829           emitConstantRange(Record, *Range, /*EmitBitWidth=*/true);
2830         }
2831         for (const Value *Op : CE->operands()) {
2832           Record.push_back(VE.getTypeID(Op->getType()));
2833           Record.push_back(VE.getValueID(Op));
2834         }
2835         break;
2836       }
2837       case Instruction::ExtractElement:
2838         Code = bitc::CST_CODE_CE_EXTRACTELT;
2839         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2840         Record.push_back(VE.getValueID(C->getOperand(0)));
2841         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
2842         Record.push_back(VE.getValueID(C->getOperand(1)));
2843         break;
2844       case Instruction::InsertElement:
2845         Code = bitc::CST_CODE_CE_INSERTELT;
2846         Record.push_back(VE.getValueID(C->getOperand(0)));
2847         Record.push_back(VE.getValueID(C->getOperand(1)));
2848         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
2849         Record.push_back(VE.getValueID(C->getOperand(2)));
2850         break;
2851       case Instruction::ShuffleVector:
2852         // If the return type and argument types are the same, this is a
2853         // standard shufflevector instruction.  If the types are different,
2854         // then the shuffle is widening or truncating the input vectors, and
2855         // the argument type must also be encoded.
2856         if (C->getType() == C->getOperand(0)->getType()) {
2857           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
2858         } else {
2859           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
2860           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2861         }
2862         Record.push_back(VE.getValueID(C->getOperand(0)));
2863         Record.push_back(VE.getValueID(C->getOperand(1)));
2864         Record.push_back(VE.getValueID(CE->getShuffleMaskForBitcode()));
2865         break;
2866       }
2867     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
2868       Code = bitc::CST_CODE_BLOCKADDRESS;
2869       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
2870       Record.push_back(VE.getValueID(BA->getFunction()));
2871       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
2872     } else if (const auto *Equiv = dyn_cast<DSOLocalEquivalent>(C)) {
2873       Code = bitc::CST_CODE_DSO_LOCAL_EQUIVALENT;
2874       Record.push_back(VE.getTypeID(Equiv->getGlobalValue()->getType()));
2875       Record.push_back(VE.getValueID(Equiv->getGlobalValue()));
2876     } else if (const auto *NC = dyn_cast<NoCFIValue>(C)) {
2877       Code = bitc::CST_CODE_NO_CFI_VALUE;
2878       Record.push_back(VE.getTypeID(NC->getGlobalValue()->getType()));
2879       Record.push_back(VE.getValueID(NC->getGlobalValue()));
2880     } else if (const auto *CPA = dyn_cast<ConstantPtrAuth>(C)) {
2881       Code = bitc::CST_CODE_PTRAUTH;
2882       Record.push_back(VE.getValueID(CPA->getPointer()));
2883       Record.push_back(VE.getValueID(CPA->getKey()));
2884       Record.push_back(VE.getValueID(CPA->getDiscriminator()));
2885       Record.push_back(VE.getValueID(CPA->getAddrDiscriminator()));
2886     } else {
2887 #ifndef NDEBUG
2888       C->dump();
2889 #endif
2890       llvm_unreachable("Unknown constant!");
2891     }
2892     Stream.EmitRecord(Code, Record, AbbrevToUse);
2893     Record.clear();
2894   }
2895 
2896   Stream.ExitBlock();
2897 }
2898 
2899 void ModuleBitcodeWriter::writeModuleConstants() {
2900   const ValueEnumerator::ValueList &Vals = VE.getValues();
2901 
2902   // Find the first constant to emit, which is the first non-globalvalue value.
2903   // We know globalvalues have been emitted by WriteModuleInfo.
2904   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
2905     if (!isa<GlobalValue>(Vals[i].first)) {
2906       writeConstants(i, Vals.size(), true);
2907       return;
2908     }
2909   }
2910 }
2911 
2912 /// pushValueAndType - The file has to encode both the value and type id for
2913 /// many values, because we need to know what type to create for forward
2914 /// references.  However, most operands are not forward references, so this type
2915 /// field is not needed.
2916 ///
2917 /// This function adds V's value ID to Vals.  If the value ID is higher than the
2918 /// instruction ID, then it is a forward reference, and it also includes the
2919 /// type ID.  The value ID that is written is encoded relative to the InstID.
2920 bool ModuleBitcodeWriter::pushValueAndType(const Value *V, unsigned InstID,
2921                                            SmallVectorImpl<unsigned> &Vals) {
2922   unsigned ValID = VE.getValueID(V);
2923   // Make encoding relative to the InstID.
2924   Vals.push_back(InstID - ValID);
2925   if (ValID >= InstID) {
2926     Vals.push_back(VE.getTypeID(V->getType()));
2927     return true;
2928   }
2929   return false;
2930 }
2931 
2932 void ModuleBitcodeWriter::writeOperandBundles(const CallBase &CS,
2933                                               unsigned InstID) {
2934   SmallVector<unsigned, 64> Record;
2935   LLVMContext &C = CS.getContext();
2936 
2937   for (unsigned i = 0, e = CS.getNumOperandBundles(); i != e; ++i) {
2938     const auto &Bundle = CS.getOperandBundleAt(i);
2939     Record.push_back(C.getOperandBundleTagID(Bundle.getTagName()));
2940 
2941     for (auto &Input : Bundle.Inputs)
2942       pushValueAndType(Input, InstID, Record);
2943 
2944     Stream.EmitRecord(bitc::FUNC_CODE_OPERAND_BUNDLE, Record);
2945     Record.clear();
2946   }
2947 }
2948 
2949 /// pushValue - Like pushValueAndType, but where the type of the value is
2950 /// omitted (perhaps it was already encoded in an earlier operand).
2951 void ModuleBitcodeWriter::pushValue(const Value *V, unsigned InstID,
2952                                     SmallVectorImpl<unsigned> &Vals) {
2953   unsigned ValID = VE.getValueID(V);
2954   Vals.push_back(InstID - ValID);
2955 }
2956 
2957 void ModuleBitcodeWriter::pushValueSigned(const Value *V, unsigned InstID,
2958                                           SmallVectorImpl<uint64_t> &Vals) {
2959   unsigned ValID = VE.getValueID(V);
2960   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
2961   emitSignedInt64(Vals, diff);
2962 }
2963 
2964 /// WriteInstruction - Emit an instruction to the specified stream.
2965 void ModuleBitcodeWriter::writeInstruction(const Instruction &I,
2966                                            unsigned InstID,
2967                                            SmallVectorImpl<unsigned> &Vals) {
2968   unsigned Code = 0;
2969   unsigned AbbrevToUse = 0;
2970   VE.setInstructionID(&I);
2971   switch (I.getOpcode()) {
2972   default:
2973     if (Instruction::isCast(I.getOpcode())) {
2974       Code = bitc::FUNC_CODE_INST_CAST;
2975       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2976         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
2977       Vals.push_back(VE.getTypeID(I.getType()));
2978       Vals.push_back(getEncodedCastOpcode(I.getOpcode()));
2979       uint64_t Flags = getOptimizationFlags(&I);
2980       if (Flags != 0) {
2981         if (AbbrevToUse == FUNCTION_INST_CAST_ABBREV)
2982           AbbrevToUse = FUNCTION_INST_CAST_FLAGS_ABBREV;
2983         Vals.push_back(Flags);
2984       }
2985     } else {
2986       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
2987       Code = bitc::FUNC_CODE_INST_BINOP;
2988       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2989         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
2990       pushValue(I.getOperand(1), InstID, Vals);
2991       Vals.push_back(getEncodedBinaryOpcode(I.getOpcode()));
2992       uint64_t Flags = getOptimizationFlags(&I);
2993       if (Flags != 0) {
2994         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
2995           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
2996         Vals.push_back(Flags);
2997       }
2998     }
2999     break;
3000   case Instruction::FNeg: {
3001     Code = bitc::FUNC_CODE_INST_UNOP;
3002     if (!pushValueAndType(I.getOperand(0), InstID, Vals))
3003       AbbrevToUse = FUNCTION_INST_UNOP_ABBREV;
3004     Vals.push_back(getEncodedUnaryOpcode(I.getOpcode()));
3005     uint64_t Flags = getOptimizationFlags(&I);
3006     if (Flags != 0) {
3007       if (AbbrevToUse == FUNCTION_INST_UNOP_ABBREV)
3008         AbbrevToUse = FUNCTION_INST_UNOP_FLAGS_ABBREV;
3009       Vals.push_back(Flags);
3010     }
3011     break;
3012   }
3013   case Instruction::GetElementPtr: {
3014     Code = bitc::FUNC_CODE_INST_GEP;
3015     AbbrevToUse = FUNCTION_INST_GEP_ABBREV;
3016     auto &GEPInst = cast<GetElementPtrInst>(I);
3017     Vals.push_back(getOptimizationFlags(&I));
3018     Vals.push_back(VE.getTypeID(GEPInst.getSourceElementType()));
3019     for (const Value *Op : I.operands())
3020       pushValueAndType(Op, InstID, Vals);
3021     break;
3022   }
3023   case Instruction::ExtractValue: {
3024     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
3025     pushValueAndType(I.getOperand(0), InstID, Vals);
3026     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
3027     Vals.append(EVI->idx_begin(), EVI->idx_end());
3028     break;
3029   }
3030   case Instruction::InsertValue: {
3031     Code = bitc::FUNC_CODE_INST_INSERTVAL;
3032     pushValueAndType(I.getOperand(0), InstID, Vals);
3033     pushValueAndType(I.getOperand(1), InstID, Vals);
3034     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
3035     Vals.append(IVI->idx_begin(), IVI->idx_end());
3036     break;
3037   }
3038   case Instruction::Select: {
3039     Code = bitc::FUNC_CODE_INST_VSELECT;
3040     pushValueAndType(I.getOperand(1), InstID, Vals);
3041     pushValue(I.getOperand(2), InstID, Vals);
3042     pushValueAndType(I.getOperand(0), InstID, Vals);
3043     uint64_t Flags = getOptimizationFlags(&I);
3044     if (Flags != 0)
3045       Vals.push_back(Flags);
3046     break;
3047   }
3048   case Instruction::ExtractElement:
3049     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
3050     pushValueAndType(I.getOperand(0), InstID, Vals);
3051     pushValueAndType(I.getOperand(1), InstID, Vals);
3052     break;
3053   case Instruction::InsertElement:
3054     Code = bitc::FUNC_CODE_INST_INSERTELT;
3055     pushValueAndType(I.getOperand(0), InstID, Vals);
3056     pushValue(I.getOperand(1), InstID, Vals);
3057     pushValueAndType(I.getOperand(2), InstID, Vals);
3058     break;
3059   case Instruction::ShuffleVector:
3060     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
3061     pushValueAndType(I.getOperand(0), InstID, Vals);
3062     pushValue(I.getOperand(1), InstID, Vals);
3063     pushValue(cast<ShuffleVectorInst>(I).getShuffleMaskForBitcode(), InstID,
3064               Vals);
3065     break;
3066   case Instruction::ICmp:
3067   case Instruction::FCmp: {
3068     // compare returning Int1Ty or vector of Int1Ty
3069     Code = bitc::FUNC_CODE_INST_CMP2;
3070     pushValueAndType(I.getOperand(0), InstID, Vals);
3071     pushValue(I.getOperand(1), InstID, Vals);
3072     Vals.push_back(cast<CmpInst>(I).getPredicate());
3073     uint64_t Flags = getOptimizationFlags(&I);
3074     if (Flags != 0)
3075       Vals.push_back(Flags);
3076     break;
3077   }
3078 
3079   case Instruction::Ret:
3080     {
3081       Code = bitc::FUNC_CODE_INST_RET;
3082       unsigned NumOperands = I.getNumOperands();
3083       if (NumOperands == 0)
3084         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
3085       else if (NumOperands == 1) {
3086         if (!pushValueAndType(I.getOperand(0), InstID, Vals))
3087           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
3088       } else {
3089         for (const Value *Op : I.operands())
3090           pushValueAndType(Op, InstID, Vals);
3091       }
3092     }
3093     break;
3094   case Instruction::Br:
3095     {
3096       Code = bitc::FUNC_CODE_INST_BR;
3097       const BranchInst &II = cast<BranchInst>(I);
3098       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
3099       if (II.isConditional()) {
3100         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
3101         pushValue(II.getCondition(), InstID, Vals);
3102       }
3103     }
3104     break;
3105   case Instruction::Switch:
3106     {
3107       Code = bitc::FUNC_CODE_INST_SWITCH;
3108       const SwitchInst &SI = cast<SwitchInst>(I);
3109       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
3110       pushValue(SI.getCondition(), InstID, Vals);
3111       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
3112       for (auto Case : SI.cases()) {
3113         Vals.push_back(VE.getValueID(Case.getCaseValue()));
3114         Vals.push_back(VE.getValueID(Case.getCaseSuccessor()));
3115       }
3116     }
3117     break;
3118   case Instruction::IndirectBr:
3119     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
3120     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
3121     // Encode the address operand as relative, but not the basic blocks.
3122     pushValue(I.getOperand(0), InstID, Vals);
3123     for (const Value *Op : drop_begin(I.operands()))
3124       Vals.push_back(VE.getValueID(Op));
3125     break;
3126 
3127   case Instruction::Invoke: {
3128     const InvokeInst *II = cast<InvokeInst>(&I);
3129     const Value *Callee = II->getCalledOperand();
3130     FunctionType *FTy = II->getFunctionType();
3131 
3132     if (II->hasOperandBundles())
3133       writeOperandBundles(*II, InstID);
3134 
3135     Code = bitc::FUNC_CODE_INST_INVOKE;
3136 
3137     Vals.push_back(VE.getAttributeListID(II->getAttributes()));
3138     Vals.push_back(II->getCallingConv() | 1 << 13);
3139     Vals.push_back(VE.getValueID(II->getNormalDest()));
3140     Vals.push_back(VE.getValueID(II->getUnwindDest()));
3141     Vals.push_back(VE.getTypeID(FTy));
3142     pushValueAndType(Callee, InstID, Vals);
3143 
3144     // Emit value #'s for the fixed parameters.
3145     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
3146       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
3147 
3148     // Emit type/value pairs for varargs params.
3149     if (FTy->isVarArg()) {
3150       for (unsigned i = FTy->getNumParams(), e = II->arg_size(); i != e; ++i)
3151         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
3152     }
3153     break;
3154   }
3155   case Instruction::Resume:
3156     Code = bitc::FUNC_CODE_INST_RESUME;
3157     pushValueAndType(I.getOperand(0), InstID, Vals);
3158     break;
3159   case Instruction::CleanupRet: {
3160     Code = bitc::FUNC_CODE_INST_CLEANUPRET;
3161     const auto &CRI = cast<CleanupReturnInst>(I);
3162     pushValue(CRI.getCleanupPad(), InstID, Vals);
3163     if (CRI.hasUnwindDest())
3164       Vals.push_back(VE.getValueID(CRI.getUnwindDest()));
3165     break;
3166   }
3167   case Instruction::CatchRet: {
3168     Code = bitc::FUNC_CODE_INST_CATCHRET;
3169     const auto &CRI = cast<CatchReturnInst>(I);
3170     pushValue(CRI.getCatchPad(), InstID, Vals);
3171     Vals.push_back(VE.getValueID(CRI.getSuccessor()));
3172     break;
3173   }
3174   case Instruction::CleanupPad:
3175   case Instruction::CatchPad: {
3176     const auto &FuncletPad = cast<FuncletPadInst>(I);
3177     Code = isa<CatchPadInst>(FuncletPad) ? bitc::FUNC_CODE_INST_CATCHPAD
3178                                          : bitc::FUNC_CODE_INST_CLEANUPPAD;
3179     pushValue(FuncletPad.getParentPad(), InstID, Vals);
3180 
3181     unsigned NumArgOperands = FuncletPad.arg_size();
3182     Vals.push_back(NumArgOperands);
3183     for (unsigned Op = 0; Op != NumArgOperands; ++Op)
3184       pushValueAndType(FuncletPad.getArgOperand(Op), InstID, Vals);
3185     break;
3186   }
3187   case Instruction::CatchSwitch: {
3188     Code = bitc::FUNC_CODE_INST_CATCHSWITCH;
3189     const auto &CatchSwitch = cast<CatchSwitchInst>(I);
3190 
3191     pushValue(CatchSwitch.getParentPad(), InstID, Vals);
3192 
3193     unsigned NumHandlers = CatchSwitch.getNumHandlers();
3194     Vals.push_back(NumHandlers);
3195     for (const BasicBlock *CatchPadBB : CatchSwitch.handlers())
3196       Vals.push_back(VE.getValueID(CatchPadBB));
3197 
3198     if (CatchSwitch.hasUnwindDest())
3199       Vals.push_back(VE.getValueID(CatchSwitch.getUnwindDest()));
3200     break;
3201   }
3202   case Instruction::CallBr: {
3203     const CallBrInst *CBI = cast<CallBrInst>(&I);
3204     const Value *Callee = CBI->getCalledOperand();
3205     FunctionType *FTy = CBI->getFunctionType();
3206 
3207     if (CBI->hasOperandBundles())
3208       writeOperandBundles(*CBI, InstID);
3209 
3210     Code = bitc::FUNC_CODE_INST_CALLBR;
3211 
3212     Vals.push_back(VE.getAttributeListID(CBI->getAttributes()));
3213 
3214     Vals.push_back(CBI->getCallingConv() << bitc::CALL_CCONV |
3215                    1 << bitc::CALL_EXPLICIT_TYPE);
3216 
3217     Vals.push_back(VE.getValueID(CBI->getDefaultDest()));
3218     Vals.push_back(CBI->getNumIndirectDests());
3219     for (unsigned i = 0, e = CBI->getNumIndirectDests(); i != e; ++i)
3220       Vals.push_back(VE.getValueID(CBI->getIndirectDest(i)));
3221 
3222     Vals.push_back(VE.getTypeID(FTy));
3223     pushValueAndType(Callee, InstID, Vals);
3224 
3225     // Emit value #'s for the fixed parameters.
3226     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
3227       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
3228 
3229     // Emit type/value pairs for varargs params.
3230     if (FTy->isVarArg()) {
3231       for (unsigned i = FTy->getNumParams(), e = CBI->arg_size(); i != e; ++i)
3232         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
3233     }
3234     break;
3235   }
3236   case Instruction::Unreachable:
3237     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
3238     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
3239     break;
3240 
3241   case Instruction::PHI: {
3242     const PHINode &PN = cast<PHINode>(I);
3243     Code = bitc::FUNC_CODE_INST_PHI;
3244     // With the newer instruction encoding, forward references could give
3245     // negative valued IDs.  This is most common for PHIs, so we use
3246     // signed VBRs.
3247     SmallVector<uint64_t, 128> Vals64;
3248     Vals64.push_back(VE.getTypeID(PN.getType()));
3249     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
3250       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64);
3251       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
3252     }
3253 
3254     uint64_t Flags = getOptimizationFlags(&I);
3255     if (Flags != 0)
3256       Vals64.push_back(Flags);
3257 
3258     // Emit a Vals64 vector and exit.
3259     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
3260     Vals64.clear();
3261     return;
3262   }
3263 
3264   case Instruction::LandingPad: {
3265     const LandingPadInst &LP = cast<LandingPadInst>(I);
3266     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
3267     Vals.push_back(VE.getTypeID(LP.getType()));
3268     Vals.push_back(LP.isCleanup());
3269     Vals.push_back(LP.getNumClauses());
3270     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
3271       if (LP.isCatch(I))
3272         Vals.push_back(LandingPadInst::Catch);
3273       else
3274         Vals.push_back(LandingPadInst::Filter);
3275       pushValueAndType(LP.getClause(I), InstID, Vals);
3276     }
3277     break;
3278   }
3279 
3280   case Instruction::Alloca: {
3281     Code = bitc::FUNC_CODE_INST_ALLOCA;
3282     const AllocaInst &AI = cast<AllocaInst>(I);
3283     Vals.push_back(VE.getTypeID(AI.getAllocatedType()));
3284     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
3285     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
3286     using APV = AllocaPackedValues;
3287     unsigned Record = 0;
3288     unsigned EncodedAlign = getEncodedAlign(AI.getAlign());
3289     Bitfield::set<APV::AlignLower>(
3290         Record, EncodedAlign & ((1 << APV::AlignLower::Bits) - 1));
3291     Bitfield::set<APV::AlignUpper>(Record,
3292                                    EncodedAlign >> APV::AlignLower::Bits);
3293     Bitfield::set<APV::UsedWithInAlloca>(Record, AI.isUsedWithInAlloca());
3294     Bitfield::set<APV::ExplicitType>(Record, true);
3295     Bitfield::set<APV::SwiftError>(Record, AI.isSwiftError());
3296     Vals.push_back(Record);
3297 
3298     unsigned AS = AI.getAddressSpace();
3299     if (AS != M.getDataLayout().getAllocaAddrSpace())
3300       Vals.push_back(AS);
3301     break;
3302   }
3303 
3304   case Instruction::Load:
3305     if (cast<LoadInst>(I).isAtomic()) {
3306       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
3307       pushValueAndType(I.getOperand(0), InstID, Vals);
3308     } else {
3309       Code = bitc::FUNC_CODE_INST_LOAD;
3310       if (!pushValueAndType(I.getOperand(0), InstID, Vals)) // ptr
3311         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
3312     }
3313     Vals.push_back(VE.getTypeID(I.getType()));
3314     Vals.push_back(getEncodedAlign(cast<LoadInst>(I).getAlign()));
3315     Vals.push_back(cast<LoadInst>(I).isVolatile());
3316     if (cast<LoadInst>(I).isAtomic()) {
3317       Vals.push_back(getEncodedOrdering(cast<LoadInst>(I).getOrdering()));
3318       Vals.push_back(getEncodedSyncScopeID(cast<LoadInst>(I).getSyncScopeID()));
3319     }
3320     break;
3321   case Instruction::Store:
3322     if (cast<StoreInst>(I).isAtomic())
3323       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
3324     else
3325       Code = bitc::FUNC_CODE_INST_STORE;
3326     pushValueAndType(I.getOperand(1), InstID, Vals); // ptrty + ptr
3327     pushValueAndType(I.getOperand(0), InstID, Vals); // valty + val
3328     Vals.push_back(getEncodedAlign(cast<StoreInst>(I).getAlign()));
3329     Vals.push_back(cast<StoreInst>(I).isVolatile());
3330     if (cast<StoreInst>(I).isAtomic()) {
3331       Vals.push_back(getEncodedOrdering(cast<StoreInst>(I).getOrdering()));
3332       Vals.push_back(
3333           getEncodedSyncScopeID(cast<StoreInst>(I).getSyncScopeID()));
3334     }
3335     break;
3336   case Instruction::AtomicCmpXchg:
3337     Code = bitc::FUNC_CODE_INST_CMPXCHG;
3338     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
3339     pushValueAndType(I.getOperand(1), InstID, Vals); // cmp.
3340     pushValue(I.getOperand(2), InstID, Vals);        // newval.
3341     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
3342     Vals.push_back(
3343         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
3344     Vals.push_back(
3345         getEncodedSyncScopeID(cast<AtomicCmpXchgInst>(I).getSyncScopeID()));
3346     Vals.push_back(
3347         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
3348     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
3349     Vals.push_back(getEncodedAlign(cast<AtomicCmpXchgInst>(I).getAlign()));
3350     break;
3351   case Instruction::AtomicRMW:
3352     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
3353     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
3354     pushValueAndType(I.getOperand(1), InstID, Vals); // valty + val
3355     Vals.push_back(
3356         getEncodedRMWOperation(cast<AtomicRMWInst>(I).getOperation()));
3357     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
3358     Vals.push_back(getEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
3359     Vals.push_back(
3360         getEncodedSyncScopeID(cast<AtomicRMWInst>(I).getSyncScopeID()));
3361     Vals.push_back(getEncodedAlign(cast<AtomicRMWInst>(I).getAlign()));
3362     break;
3363   case Instruction::Fence:
3364     Code = bitc::FUNC_CODE_INST_FENCE;
3365     Vals.push_back(getEncodedOrdering(cast<FenceInst>(I).getOrdering()));
3366     Vals.push_back(getEncodedSyncScopeID(cast<FenceInst>(I).getSyncScopeID()));
3367     break;
3368   case Instruction::Call: {
3369     const CallInst &CI = cast<CallInst>(I);
3370     FunctionType *FTy = CI.getFunctionType();
3371 
3372     if (CI.hasOperandBundles())
3373       writeOperandBundles(CI, InstID);
3374 
3375     Code = bitc::FUNC_CODE_INST_CALL;
3376 
3377     Vals.push_back(VE.getAttributeListID(CI.getAttributes()));
3378 
3379     unsigned Flags = getOptimizationFlags(&I);
3380     Vals.push_back(CI.getCallingConv() << bitc::CALL_CCONV |
3381                    unsigned(CI.isTailCall()) << bitc::CALL_TAIL |
3382                    unsigned(CI.isMustTailCall()) << bitc::CALL_MUSTTAIL |
3383                    1 << bitc::CALL_EXPLICIT_TYPE |
3384                    unsigned(CI.isNoTailCall()) << bitc::CALL_NOTAIL |
3385                    unsigned(Flags != 0) << bitc::CALL_FMF);
3386     if (Flags != 0)
3387       Vals.push_back(Flags);
3388 
3389     Vals.push_back(VE.getTypeID(FTy));
3390     pushValueAndType(CI.getCalledOperand(), InstID, Vals); // Callee
3391 
3392     // Emit value #'s for the fixed parameters.
3393     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
3394       // Check for labels (can happen with asm labels).
3395       if (FTy->getParamType(i)->isLabelTy())
3396         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
3397       else
3398         pushValue(CI.getArgOperand(i), InstID, Vals); // fixed param.
3399     }
3400 
3401     // Emit type/value pairs for varargs params.
3402     if (FTy->isVarArg()) {
3403       for (unsigned i = FTy->getNumParams(), e = CI.arg_size(); i != e; ++i)
3404         pushValueAndType(CI.getArgOperand(i), InstID, Vals); // varargs
3405     }
3406     break;
3407   }
3408   case Instruction::VAArg:
3409     Code = bitc::FUNC_CODE_INST_VAARG;
3410     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
3411     pushValue(I.getOperand(0), InstID, Vals);                   // valist.
3412     Vals.push_back(VE.getTypeID(I.getType())); // restype.
3413     break;
3414   case Instruction::Freeze:
3415     Code = bitc::FUNC_CODE_INST_FREEZE;
3416     pushValueAndType(I.getOperand(0), InstID, Vals);
3417     break;
3418   }
3419 
3420   Stream.EmitRecord(Code, Vals, AbbrevToUse);
3421   Vals.clear();
3422 }
3423 
3424 /// Write a GlobalValue VST to the module. The purpose of this data structure is
3425 /// to allow clients to efficiently find the function body.
3426 void ModuleBitcodeWriter::writeGlobalValueSymbolTable(
3427   DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3428   // Get the offset of the VST we are writing, and backpatch it into
3429   // the VST forward declaration record.
3430   uint64_t VSTOffset = Stream.GetCurrentBitNo();
3431   // The BitcodeStartBit was the stream offset of the identification block.
3432   VSTOffset -= bitcodeStartBit();
3433   assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
3434   // Note that we add 1 here because the offset is relative to one word
3435   // before the start of the identification block, which was historically
3436   // always the start of the regular bitcode header.
3437   Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32 + 1);
3438 
3439   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3440 
3441   auto Abbv = std::make_shared<BitCodeAbbrev>();
3442   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
3443   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
3444   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
3445   unsigned FnEntryAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3446 
3447   for (const Function &F : M) {
3448     uint64_t Record[2];
3449 
3450     if (F.isDeclaration())
3451       continue;
3452 
3453     Record[0] = VE.getValueID(&F);
3454 
3455     // Save the word offset of the function (from the start of the
3456     // actual bitcode written to the stream).
3457     uint64_t BitcodeIndex = FunctionToBitcodeIndex[&F] - bitcodeStartBit();
3458     assert((BitcodeIndex & 31) == 0 && "function block not 32-bit aligned");
3459     // Note that we add 1 here because the offset is relative to one word
3460     // before the start of the identification block, which was historically
3461     // always the start of the regular bitcode header.
3462     Record[1] = BitcodeIndex / 32 + 1;
3463 
3464     Stream.EmitRecord(bitc::VST_CODE_FNENTRY, Record, FnEntryAbbrev);
3465   }
3466 
3467   Stream.ExitBlock();
3468 }
3469 
3470 /// Emit names for arguments, instructions and basic blocks in a function.
3471 void ModuleBitcodeWriter::writeFunctionLevelValueSymbolTable(
3472     const ValueSymbolTable &VST) {
3473   if (VST.empty())
3474     return;
3475 
3476   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3477 
3478   // FIXME: Set up the abbrev, we know how many values there are!
3479   // FIXME: We know if the type names can use 7-bit ascii.
3480   SmallVector<uint64_t, 64> NameVals;
3481 
3482   for (const ValueName &Name : VST) {
3483     // Figure out the encoding to use for the name.
3484     StringEncoding Bits = getStringEncoding(Name.getKey());
3485 
3486     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
3487     NameVals.push_back(VE.getValueID(Name.getValue()));
3488 
3489     // VST_CODE_ENTRY:   [valueid, namechar x N]
3490     // VST_CODE_BBENTRY: [bbid, namechar x N]
3491     unsigned Code;
3492     if (isa<BasicBlock>(Name.getValue())) {
3493       Code = bitc::VST_CODE_BBENTRY;
3494       if (Bits == SE_Char6)
3495         AbbrevToUse = VST_BBENTRY_6_ABBREV;
3496     } else {
3497       Code = bitc::VST_CODE_ENTRY;
3498       if (Bits == SE_Char6)
3499         AbbrevToUse = VST_ENTRY_6_ABBREV;
3500       else if (Bits == SE_Fixed7)
3501         AbbrevToUse = VST_ENTRY_7_ABBREV;
3502     }
3503 
3504     for (const auto P : Name.getKey())
3505       NameVals.push_back((unsigned char)P);
3506 
3507     // Emit the finished record.
3508     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
3509     NameVals.clear();
3510   }
3511 
3512   Stream.ExitBlock();
3513 }
3514 
3515 void ModuleBitcodeWriter::writeUseList(UseListOrder &&Order) {
3516   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
3517   unsigned Code;
3518   if (isa<BasicBlock>(Order.V))
3519     Code = bitc::USELIST_CODE_BB;
3520   else
3521     Code = bitc::USELIST_CODE_DEFAULT;
3522 
3523   SmallVector<uint64_t, 64> Record(Order.Shuffle.begin(), Order.Shuffle.end());
3524   Record.push_back(VE.getValueID(Order.V));
3525   Stream.EmitRecord(Code, Record);
3526 }
3527 
3528 void ModuleBitcodeWriter::writeUseListBlock(const Function *F) {
3529   assert(VE.shouldPreserveUseListOrder() &&
3530          "Expected to be preserving use-list order");
3531 
3532   auto hasMore = [&]() {
3533     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
3534   };
3535   if (!hasMore())
3536     // Nothing to do.
3537     return;
3538 
3539   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
3540   while (hasMore()) {
3541     writeUseList(std::move(VE.UseListOrders.back()));
3542     VE.UseListOrders.pop_back();
3543   }
3544   Stream.ExitBlock();
3545 }
3546 
3547 /// Emit a function body to the module stream.
3548 void ModuleBitcodeWriter::writeFunction(
3549     const Function &F,
3550     DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3551   // Save the bitcode index of the start of this function block for recording
3552   // in the VST.
3553   FunctionToBitcodeIndex[&F] = Stream.GetCurrentBitNo();
3554 
3555   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
3556   VE.incorporateFunction(F);
3557 
3558   SmallVector<unsigned, 64> Vals;
3559 
3560   // Emit the number of basic blocks, so the reader can create them ahead of
3561   // time.
3562   Vals.push_back(VE.getBasicBlocks().size());
3563   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
3564   Vals.clear();
3565 
3566   // If there are function-local constants, emit them now.
3567   unsigned CstStart, CstEnd;
3568   VE.getFunctionConstantRange(CstStart, CstEnd);
3569   writeConstants(CstStart, CstEnd, false);
3570 
3571   // If there is function-local metadata, emit it now.
3572   writeFunctionMetadata(F);
3573 
3574   // Keep a running idea of what the instruction ID is.
3575   unsigned InstID = CstEnd;
3576 
3577   bool NeedsMetadataAttachment = F.hasMetadata();
3578 
3579   DILocation *LastDL = nullptr;
3580   SmallSetVector<Function *, 4> BlockAddressUsers;
3581 
3582   // Finally, emit all the instructions, in order.
3583   for (const BasicBlock &BB : F) {
3584     for (const Instruction &I : BB) {
3585       writeInstruction(I, InstID, Vals);
3586 
3587       if (!I.getType()->isVoidTy())
3588         ++InstID;
3589 
3590       // If the instruction has metadata, write a metadata attachment later.
3591       NeedsMetadataAttachment |= I.hasMetadataOtherThanDebugLoc();
3592 
3593       // If the instruction has a debug location, emit it.
3594       if (DILocation *DL = I.getDebugLoc()) {
3595         if (DL == LastDL) {
3596           // Just repeat the same debug loc as last time.
3597           Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
3598         } else {
3599           Vals.push_back(DL->getLine());
3600           Vals.push_back(DL->getColumn());
3601           Vals.push_back(VE.getMetadataOrNullID(DL->getScope()));
3602           Vals.push_back(VE.getMetadataOrNullID(DL->getInlinedAt()));
3603           Vals.push_back(DL->isImplicitCode());
3604           Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
3605           Vals.clear();
3606           LastDL = DL;
3607         }
3608       }
3609 
3610       // If the instruction has DbgRecords attached to it, emit them. Note that
3611       // they come after the instruction so that it's easy to attach them again
3612       // when reading the bitcode, even though conceptually the debug locations
3613       // start "before" the instruction.
3614       if (I.hasDbgRecords() && WriteNewDbgInfoFormatToBitcode) {
3615         /// Try to push the value only (unwrapped), otherwise push the
3616         /// metadata wrapped value. Returns true if the value was pushed
3617         /// without the ValueAsMetadata wrapper.
3618         auto PushValueOrMetadata = [&Vals, InstID,
3619                                     this](Metadata *RawLocation) {
3620           assert(RawLocation &&
3621                  "RawLocation unexpectedly null in DbgVariableRecord");
3622           if (ValueAsMetadata *VAM = dyn_cast<ValueAsMetadata>(RawLocation)) {
3623             SmallVector<unsigned, 2> ValAndType;
3624             // If the value is a fwd-ref the type is also pushed. We don't
3625             // want the type, so fwd-refs are kept wrapped (pushValueAndType
3626             // returns false if the value is pushed without type).
3627             if (!pushValueAndType(VAM->getValue(), InstID, ValAndType)) {
3628               Vals.push_back(ValAndType[0]);
3629               return true;
3630             }
3631           }
3632           // The metadata is a DIArgList, or ValueAsMetadata wrapping a
3633           // fwd-ref. Push the metadata ID.
3634           Vals.push_back(VE.getMetadataID(RawLocation));
3635           return false;
3636         };
3637 
3638         // Write out non-instruction debug information attached to this
3639         // instruction. Write it after the instruction so that it's easy to
3640         // re-attach to the instruction reading the records in.
3641         for (DbgRecord &DR : I.DebugMarker->getDbgRecordRange()) {
3642           if (DbgLabelRecord *DLR = dyn_cast<DbgLabelRecord>(&DR)) {
3643             Vals.push_back(VE.getMetadataID(&*DLR->getDebugLoc()));
3644             Vals.push_back(VE.getMetadataID(DLR->getLabel()));
3645             Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_RECORD_LABEL, Vals);
3646             Vals.clear();
3647             continue;
3648           }
3649 
3650           // First 3 fields are common to all kinds:
3651           //   DILocation, DILocalVariable, DIExpression
3652           // dbg_value (FUNC_CODE_DEBUG_RECORD_VALUE)
3653           //   ..., LocationMetadata
3654           // dbg_value (FUNC_CODE_DEBUG_RECORD_VALUE_SIMPLE - abbrev'd)
3655           //   ..., Value
3656           // dbg_declare (FUNC_CODE_DEBUG_RECORD_DECLARE)
3657           //   ..., LocationMetadata
3658           // dbg_assign (FUNC_CODE_DEBUG_RECORD_ASSIGN)
3659           //   ..., LocationMetadata, DIAssignID, DIExpression, LocationMetadata
3660           DbgVariableRecord &DVR = cast<DbgVariableRecord>(DR);
3661           Vals.push_back(VE.getMetadataID(&*DVR.getDebugLoc()));
3662           Vals.push_back(VE.getMetadataID(DVR.getVariable()));
3663           Vals.push_back(VE.getMetadataID(DVR.getExpression()));
3664           if (DVR.isDbgValue()) {
3665             if (PushValueOrMetadata(DVR.getRawLocation()))
3666               Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_RECORD_VALUE_SIMPLE, Vals,
3667                                 FUNCTION_DEBUG_RECORD_VALUE_ABBREV);
3668             else
3669               Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_RECORD_VALUE, Vals);
3670           } else if (DVR.isDbgDeclare()) {
3671             Vals.push_back(VE.getMetadataID(DVR.getRawLocation()));
3672             Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_RECORD_DECLARE, Vals);
3673           } else {
3674             assert(DVR.isDbgAssign() && "Unexpected DbgRecord kind");
3675             Vals.push_back(VE.getMetadataID(DVR.getRawLocation()));
3676             Vals.push_back(VE.getMetadataID(DVR.getAssignID()));
3677             Vals.push_back(VE.getMetadataID(DVR.getAddressExpression()));
3678             Vals.push_back(VE.getMetadataID(DVR.getRawAddress()));
3679             Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_RECORD_ASSIGN, Vals);
3680           }
3681           Vals.clear();
3682         }
3683       }
3684     }
3685 
3686     if (BlockAddress *BA = BlockAddress::lookup(&BB)) {
3687       SmallVector<Value *> Worklist{BA};
3688       SmallPtrSet<Value *, 8> Visited{BA};
3689       while (!Worklist.empty()) {
3690         Value *V = Worklist.pop_back_val();
3691         for (User *U : V->users()) {
3692           if (auto *I = dyn_cast<Instruction>(U)) {
3693             Function *P = I->getFunction();
3694             if (P != &F)
3695               BlockAddressUsers.insert(P);
3696           } else if (isa<Constant>(U) && !isa<GlobalValue>(U) &&
3697                      Visited.insert(U).second)
3698             Worklist.push_back(U);
3699         }
3700       }
3701     }
3702   }
3703 
3704   if (!BlockAddressUsers.empty()) {
3705     Vals.resize(BlockAddressUsers.size());
3706     for (auto I : llvm::enumerate(BlockAddressUsers))
3707       Vals[I.index()] = VE.getValueID(I.value());
3708     Stream.EmitRecord(bitc::FUNC_CODE_BLOCKADDR_USERS, Vals);
3709     Vals.clear();
3710   }
3711 
3712   // Emit names for all the instructions etc.
3713   if (auto *Symtab = F.getValueSymbolTable())
3714     writeFunctionLevelValueSymbolTable(*Symtab);
3715 
3716   if (NeedsMetadataAttachment)
3717     writeFunctionMetadataAttachment(F);
3718   if (VE.shouldPreserveUseListOrder())
3719     writeUseListBlock(&F);
3720   VE.purgeFunction();
3721   Stream.ExitBlock();
3722 }
3723 
3724 // Emit blockinfo, which defines the standard abbreviations etc.
3725 void ModuleBitcodeWriter::writeBlockInfo() {
3726   // We only want to emit block info records for blocks that have multiple
3727   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
3728   // Other blocks can define their abbrevs inline.
3729   Stream.EnterBlockInfoBlock();
3730 
3731   { // 8-bit fixed-width VST_CODE_ENTRY/VST_CODE_BBENTRY strings.
3732     auto Abbv = std::make_shared<BitCodeAbbrev>();
3733     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
3734     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3735     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3736     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3737     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3738         VST_ENTRY_8_ABBREV)
3739       llvm_unreachable("Unexpected abbrev ordering!");
3740   }
3741 
3742   { // 7-bit fixed width VST_CODE_ENTRY strings.
3743     auto Abbv = std::make_shared<BitCodeAbbrev>();
3744     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3745     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3746     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3747     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3748     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3749         VST_ENTRY_7_ABBREV)
3750       llvm_unreachable("Unexpected abbrev ordering!");
3751   }
3752   { // 6-bit char6 VST_CODE_ENTRY strings.
3753     auto Abbv = std::make_shared<BitCodeAbbrev>();
3754     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3755     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3756     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3757     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3758     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3759         VST_ENTRY_6_ABBREV)
3760       llvm_unreachable("Unexpected abbrev ordering!");
3761   }
3762   { // 6-bit char6 VST_CODE_BBENTRY strings.
3763     auto Abbv = std::make_shared<BitCodeAbbrev>();
3764     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
3765     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3766     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3767     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3768     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3769         VST_BBENTRY_6_ABBREV)
3770       llvm_unreachable("Unexpected abbrev ordering!");
3771   }
3772 
3773   { // SETTYPE abbrev for CONSTANTS_BLOCK.
3774     auto Abbv = std::make_shared<BitCodeAbbrev>();
3775     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
3776     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
3777                               VE.computeBitsRequiredForTypeIndices()));
3778     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3779         CONSTANTS_SETTYPE_ABBREV)
3780       llvm_unreachable("Unexpected abbrev ordering!");
3781   }
3782 
3783   { // INTEGER abbrev for CONSTANTS_BLOCK.
3784     auto Abbv = std::make_shared<BitCodeAbbrev>();
3785     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
3786     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3787     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3788         CONSTANTS_INTEGER_ABBREV)
3789       llvm_unreachable("Unexpected abbrev ordering!");
3790   }
3791 
3792   { // CE_CAST abbrev for CONSTANTS_BLOCK.
3793     auto Abbv = std::make_shared<BitCodeAbbrev>();
3794     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
3795     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
3796     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
3797                               VE.computeBitsRequiredForTypeIndices()));
3798     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
3799 
3800     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3801         CONSTANTS_CE_CAST_Abbrev)
3802       llvm_unreachable("Unexpected abbrev ordering!");
3803   }
3804   { // NULL abbrev for CONSTANTS_BLOCK.
3805     auto Abbv = std::make_shared<BitCodeAbbrev>();
3806     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
3807     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3808         CONSTANTS_NULL_Abbrev)
3809       llvm_unreachable("Unexpected abbrev ordering!");
3810   }
3811 
3812   // FIXME: This should only use space for first class types!
3813 
3814   { // INST_LOAD abbrev for FUNCTION_BLOCK.
3815     auto Abbv = std::make_shared<BitCodeAbbrev>();
3816     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
3817     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
3818     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
3819                               VE.computeBitsRequiredForTypeIndices()));
3820     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
3821     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
3822     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3823         FUNCTION_INST_LOAD_ABBREV)
3824       llvm_unreachable("Unexpected abbrev ordering!");
3825   }
3826   { // INST_UNOP abbrev for FUNCTION_BLOCK.
3827     auto Abbv = std::make_shared<BitCodeAbbrev>();
3828     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3829     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3830     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3831     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3832         FUNCTION_INST_UNOP_ABBREV)
3833       llvm_unreachable("Unexpected abbrev ordering!");
3834   }
3835   { // INST_UNOP_FLAGS abbrev for FUNCTION_BLOCK.
3836     auto Abbv = std::make_shared<BitCodeAbbrev>();
3837     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3838     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3839     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3840     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3841     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3842         FUNCTION_INST_UNOP_FLAGS_ABBREV)
3843       llvm_unreachable("Unexpected abbrev ordering!");
3844   }
3845   { // INST_BINOP abbrev for FUNCTION_BLOCK.
3846     auto Abbv = std::make_shared<BitCodeAbbrev>();
3847     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3848     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3849     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3850     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3851     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3852         FUNCTION_INST_BINOP_ABBREV)
3853       llvm_unreachable("Unexpected abbrev ordering!");
3854   }
3855   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
3856     auto Abbv = std::make_shared<BitCodeAbbrev>();
3857     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3858     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3859     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3860     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3861     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3862     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3863         FUNCTION_INST_BINOP_FLAGS_ABBREV)
3864       llvm_unreachable("Unexpected abbrev ordering!");
3865   }
3866   { // INST_CAST abbrev for FUNCTION_BLOCK.
3867     auto Abbv = std::make_shared<BitCodeAbbrev>();
3868     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
3869     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
3870     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
3871                               VE.computeBitsRequiredForTypeIndices()));
3872     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
3873     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3874         FUNCTION_INST_CAST_ABBREV)
3875       llvm_unreachable("Unexpected abbrev ordering!");
3876   }
3877   { // INST_CAST_FLAGS abbrev for FUNCTION_BLOCK.
3878     auto Abbv = std::make_shared<BitCodeAbbrev>();
3879     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
3880     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // OpVal
3881     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
3882                               VE.computeBitsRequiredForTypeIndices()));
3883     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3884     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3885     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3886         FUNCTION_INST_CAST_FLAGS_ABBREV)
3887       llvm_unreachable("Unexpected abbrev ordering!");
3888   }
3889 
3890   { // INST_RET abbrev for FUNCTION_BLOCK.
3891     auto Abbv = std::make_shared<BitCodeAbbrev>();
3892     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3893     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3894         FUNCTION_INST_RET_VOID_ABBREV)
3895       llvm_unreachable("Unexpected abbrev ordering!");
3896   }
3897   { // INST_RET abbrev for FUNCTION_BLOCK.
3898     auto Abbv = std::make_shared<BitCodeAbbrev>();
3899     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3900     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
3901     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3902         FUNCTION_INST_RET_VAL_ABBREV)
3903       llvm_unreachable("Unexpected abbrev ordering!");
3904   }
3905   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
3906     auto Abbv = std::make_shared<BitCodeAbbrev>();
3907     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
3908     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3909         FUNCTION_INST_UNREACHABLE_ABBREV)
3910       llvm_unreachable("Unexpected abbrev ordering!");
3911   }
3912   {
3913     auto Abbv = std::make_shared<BitCodeAbbrev>();
3914     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_GEP));
3915     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
3916     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, // dest ty
3917                               Log2_32_Ceil(VE.getTypes().size() + 1)));
3918     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3919     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
3920     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3921         FUNCTION_INST_GEP_ABBREV)
3922       llvm_unreachable("Unexpected abbrev ordering!");
3923   }
3924   {
3925     auto Abbv = std::make_shared<BitCodeAbbrev>();
3926     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_DEBUG_RECORD_VALUE_SIMPLE));
3927     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 7)); // dbgloc
3928     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 7)); // var
3929     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 7)); // expr
3930     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // val
3931     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3932         FUNCTION_DEBUG_RECORD_VALUE_ABBREV)
3933       llvm_unreachable("Unexpected abbrev ordering! 1");
3934   }
3935   Stream.ExitBlock();
3936 }
3937 
3938 /// Write the module path strings, currently only used when generating
3939 /// a combined index file.
3940 void IndexBitcodeWriter::writeModStrings() {
3941   Stream.EnterSubblock(bitc::MODULE_STRTAB_BLOCK_ID, 3);
3942 
3943   // TODO: See which abbrev sizes we actually need to emit
3944 
3945   // 8-bit fixed-width MST_ENTRY strings.
3946   auto Abbv = std::make_shared<BitCodeAbbrev>();
3947   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3948   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3949   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3950   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3951   unsigned Abbrev8Bit = Stream.EmitAbbrev(std::move(Abbv));
3952 
3953   // 7-bit fixed width MST_ENTRY strings.
3954   Abbv = std::make_shared<BitCodeAbbrev>();
3955   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3956   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3957   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3958   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3959   unsigned Abbrev7Bit = Stream.EmitAbbrev(std::move(Abbv));
3960 
3961   // 6-bit char6 MST_ENTRY strings.
3962   Abbv = std::make_shared<BitCodeAbbrev>();
3963   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3964   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3965   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3966   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3967   unsigned Abbrev6Bit = Stream.EmitAbbrev(std::move(Abbv));
3968 
3969   // Module Hash, 160 bits SHA1. Optionally, emitted after each MST_CODE_ENTRY.
3970   Abbv = std::make_shared<BitCodeAbbrev>();
3971   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_HASH));
3972   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3973   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3974   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3975   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3976   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3977   unsigned AbbrevHash = Stream.EmitAbbrev(std::move(Abbv));
3978 
3979   SmallVector<unsigned, 64> Vals;
3980   forEachModule([&](const StringMapEntry<ModuleHash> &MPSE) {
3981     StringRef Key = MPSE.getKey();
3982     const auto &Hash = MPSE.getValue();
3983     StringEncoding Bits = getStringEncoding(Key);
3984     unsigned AbbrevToUse = Abbrev8Bit;
3985     if (Bits == SE_Char6)
3986       AbbrevToUse = Abbrev6Bit;
3987     else if (Bits == SE_Fixed7)
3988       AbbrevToUse = Abbrev7Bit;
3989 
3990     auto ModuleId = ModuleIdMap.size();
3991     ModuleIdMap[Key] = ModuleId;
3992     Vals.push_back(ModuleId);
3993     Vals.append(Key.begin(), Key.end());
3994 
3995     // Emit the finished record.
3996     Stream.EmitRecord(bitc::MST_CODE_ENTRY, Vals, AbbrevToUse);
3997 
3998     // Emit an optional hash for the module now
3999     if (llvm::any_of(Hash, [](uint32_t H) { return H; })) {
4000       Vals.assign(Hash.begin(), Hash.end());
4001       // Emit the hash record.
4002       Stream.EmitRecord(bitc::MST_CODE_HASH, Vals, AbbrevHash);
4003     }
4004 
4005     Vals.clear();
4006   });
4007   Stream.ExitBlock();
4008 }
4009 
4010 /// Write the function type metadata related records that need to appear before
4011 /// a function summary entry (whether per-module or combined).
4012 template <typename Fn>
4013 static void writeFunctionTypeMetadataRecords(BitstreamWriter &Stream,
4014                                              FunctionSummary *FS,
4015                                              Fn GetValueID) {
4016   if (!FS->type_tests().empty())
4017     Stream.EmitRecord(bitc::FS_TYPE_TESTS, FS->type_tests());
4018 
4019   SmallVector<uint64_t, 64> Record;
4020 
4021   auto WriteVFuncIdVec = [&](uint64_t Ty,
4022                              ArrayRef<FunctionSummary::VFuncId> VFs) {
4023     if (VFs.empty())
4024       return;
4025     Record.clear();
4026     for (auto &VF : VFs) {
4027       Record.push_back(VF.GUID);
4028       Record.push_back(VF.Offset);
4029     }
4030     Stream.EmitRecord(Ty, Record);
4031   };
4032 
4033   WriteVFuncIdVec(bitc::FS_TYPE_TEST_ASSUME_VCALLS,
4034                   FS->type_test_assume_vcalls());
4035   WriteVFuncIdVec(bitc::FS_TYPE_CHECKED_LOAD_VCALLS,
4036                   FS->type_checked_load_vcalls());
4037 
4038   auto WriteConstVCallVec = [&](uint64_t Ty,
4039                                 ArrayRef<FunctionSummary::ConstVCall> VCs) {
4040     for (auto &VC : VCs) {
4041       Record.clear();
4042       Record.push_back(VC.VFunc.GUID);
4043       Record.push_back(VC.VFunc.Offset);
4044       llvm::append_range(Record, VC.Args);
4045       Stream.EmitRecord(Ty, Record);
4046     }
4047   };
4048 
4049   WriteConstVCallVec(bitc::FS_TYPE_TEST_ASSUME_CONST_VCALL,
4050                      FS->type_test_assume_const_vcalls());
4051   WriteConstVCallVec(bitc::FS_TYPE_CHECKED_LOAD_CONST_VCALL,
4052                      FS->type_checked_load_const_vcalls());
4053 
4054   auto WriteRange = [&](ConstantRange Range) {
4055     Range = Range.sextOrTrunc(FunctionSummary::ParamAccess::RangeWidth);
4056     assert(Range.getLower().getNumWords() == 1);
4057     assert(Range.getUpper().getNumWords() == 1);
4058     emitSignedInt64(Record, *Range.getLower().getRawData());
4059     emitSignedInt64(Record, *Range.getUpper().getRawData());
4060   };
4061 
4062   if (!FS->paramAccesses().empty()) {
4063     Record.clear();
4064     for (auto &Arg : FS->paramAccesses()) {
4065       size_t UndoSize = Record.size();
4066       Record.push_back(Arg.ParamNo);
4067       WriteRange(Arg.Use);
4068       Record.push_back(Arg.Calls.size());
4069       for (auto &Call : Arg.Calls) {
4070         Record.push_back(Call.ParamNo);
4071         std::optional<unsigned> ValueID = GetValueID(Call.Callee);
4072         if (!ValueID) {
4073           // If ValueID is unknown we can't drop just this call, we must drop
4074           // entire parameter.
4075           Record.resize(UndoSize);
4076           break;
4077         }
4078         Record.push_back(*ValueID);
4079         WriteRange(Call.Offsets);
4080       }
4081     }
4082     if (!Record.empty())
4083       Stream.EmitRecord(bitc::FS_PARAM_ACCESS, Record);
4084   }
4085 }
4086 
4087 /// Collect type IDs from type tests used by function.
4088 static void
4089 getReferencedTypeIds(FunctionSummary *FS,
4090                      std::set<GlobalValue::GUID> &ReferencedTypeIds) {
4091   if (!FS->type_tests().empty())
4092     for (auto &TT : FS->type_tests())
4093       ReferencedTypeIds.insert(TT);
4094 
4095   auto GetReferencedTypesFromVFuncIdVec =
4096       [&](ArrayRef<FunctionSummary::VFuncId> VFs) {
4097         for (auto &VF : VFs)
4098           ReferencedTypeIds.insert(VF.GUID);
4099       };
4100 
4101   GetReferencedTypesFromVFuncIdVec(FS->type_test_assume_vcalls());
4102   GetReferencedTypesFromVFuncIdVec(FS->type_checked_load_vcalls());
4103 
4104   auto GetReferencedTypesFromConstVCallVec =
4105       [&](ArrayRef<FunctionSummary::ConstVCall> VCs) {
4106         for (auto &VC : VCs)
4107           ReferencedTypeIds.insert(VC.VFunc.GUID);
4108       };
4109 
4110   GetReferencedTypesFromConstVCallVec(FS->type_test_assume_const_vcalls());
4111   GetReferencedTypesFromConstVCallVec(FS->type_checked_load_const_vcalls());
4112 }
4113 
4114 static void writeWholeProgramDevirtResolutionByArg(
4115     SmallVector<uint64_t, 64> &NameVals, const std::vector<uint64_t> &args,
4116     const WholeProgramDevirtResolution::ByArg &ByArg) {
4117   NameVals.push_back(args.size());
4118   llvm::append_range(NameVals, args);
4119 
4120   NameVals.push_back(ByArg.TheKind);
4121   NameVals.push_back(ByArg.Info);
4122   NameVals.push_back(ByArg.Byte);
4123   NameVals.push_back(ByArg.Bit);
4124 }
4125 
4126 static void writeWholeProgramDevirtResolution(
4127     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
4128     uint64_t Id, const WholeProgramDevirtResolution &Wpd) {
4129   NameVals.push_back(Id);
4130 
4131   NameVals.push_back(Wpd.TheKind);
4132   NameVals.push_back(StrtabBuilder.add(Wpd.SingleImplName));
4133   NameVals.push_back(Wpd.SingleImplName.size());
4134 
4135   NameVals.push_back(Wpd.ResByArg.size());
4136   for (auto &A : Wpd.ResByArg)
4137     writeWholeProgramDevirtResolutionByArg(NameVals, A.first, A.second);
4138 }
4139 
4140 static void writeTypeIdSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
4141                                      StringTableBuilder &StrtabBuilder,
4142                                      const std::string &Id,
4143                                      const TypeIdSummary &Summary) {
4144   NameVals.push_back(StrtabBuilder.add(Id));
4145   NameVals.push_back(Id.size());
4146 
4147   NameVals.push_back(Summary.TTRes.TheKind);
4148   NameVals.push_back(Summary.TTRes.SizeM1BitWidth);
4149   NameVals.push_back(Summary.TTRes.AlignLog2);
4150   NameVals.push_back(Summary.TTRes.SizeM1);
4151   NameVals.push_back(Summary.TTRes.BitMask);
4152   NameVals.push_back(Summary.TTRes.InlineBits);
4153 
4154   for (auto &W : Summary.WPDRes)
4155     writeWholeProgramDevirtResolution(NameVals, StrtabBuilder, W.first,
4156                                       W.second);
4157 }
4158 
4159 static void writeTypeIdCompatibleVtableSummaryRecord(
4160     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
4161     const std::string &Id, const TypeIdCompatibleVtableInfo &Summary,
4162     ValueEnumerator &VE) {
4163   NameVals.push_back(StrtabBuilder.add(Id));
4164   NameVals.push_back(Id.size());
4165 
4166   for (auto &P : Summary) {
4167     NameVals.push_back(P.AddressPointOffset);
4168     NameVals.push_back(VE.getValueID(P.VTableVI.getValue()));
4169   }
4170 }
4171 
4172 static void writeFunctionHeapProfileRecords(
4173     BitstreamWriter &Stream, FunctionSummary *FS, unsigned CallsiteAbbrev,
4174     unsigned AllocAbbrev, bool PerModule,
4175     std::function<unsigned(const ValueInfo &VI)> GetValueID,
4176     std::function<unsigned(unsigned)> GetStackIndex) {
4177   SmallVector<uint64_t> Record;
4178 
4179   for (auto &CI : FS->callsites()) {
4180     Record.clear();
4181     // Per module callsite clones should always have a single entry of
4182     // value 0.
4183     assert(!PerModule || (CI.Clones.size() == 1 && CI.Clones[0] == 0));
4184     Record.push_back(GetValueID(CI.Callee));
4185     if (!PerModule) {
4186       Record.push_back(CI.StackIdIndices.size());
4187       Record.push_back(CI.Clones.size());
4188     }
4189     for (auto Id : CI.StackIdIndices)
4190       Record.push_back(GetStackIndex(Id));
4191     if (!PerModule) {
4192       for (auto V : CI.Clones)
4193         Record.push_back(V);
4194     }
4195     Stream.EmitRecord(PerModule ? bitc::FS_PERMODULE_CALLSITE_INFO
4196                                 : bitc::FS_COMBINED_CALLSITE_INFO,
4197                       Record, CallsiteAbbrev);
4198   }
4199 
4200   for (auto &AI : FS->allocs()) {
4201     Record.clear();
4202     // Per module alloc versions should always have a single entry of
4203     // value 0.
4204     assert(!PerModule || (AI.Versions.size() == 1 && AI.Versions[0] == 0));
4205     Record.push_back(AI.MIBs.size());
4206     if (!PerModule)
4207       Record.push_back(AI.Versions.size());
4208     for (auto &MIB : AI.MIBs) {
4209       Record.push_back((uint8_t)MIB.AllocType);
4210       Record.push_back(MIB.StackIdIndices.size());
4211       for (auto Id : MIB.StackIdIndices)
4212         Record.push_back(GetStackIndex(Id));
4213     }
4214     if (!PerModule) {
4215       for (auto V : AI.Versions)
4216         Record.push_back(V);
4217     }
4218     assert(AI.TotalSizes.empty() || AI.TotalSizes.size() == AI.MIBs.size());
4219     if (!AI.TotalSizes.empty()) {
4220       for (auto Size : AI.TotalSizes)
4221         Record.push_back(Size);
4222     }
4223     Stream.EmitRecord(PerModule ? bitc::FS_PERMODULE_ALLOC_INFO
4224                                 : bitc::FS_COMBINED_ALLOC_INFO,
4225                       Record, AllocAbbrev);
4226   }
4227 }
4228 
4229 // Helper to emit a single function summary record.
4230 void ModuleBitcodeWriterBase::writePerModuleFunctionSummaryRecord(
4231     SmallVector<uint64_t, 64> &NameVals, GlobalValueSummary *Summary,
4232     unsigned ValueID, unsigned FSCallsRelBFAbbrev,
4233     unsigned FSCallsProfileAbbrev, unsigned CallsiteAbbrev,
4234     unsigned AllocAbbrev, const Function &F) {
4235   NameVals.push_back(ValueID);
4236 
4237   FunctionSummary *FS = cast<FunctionSummary>(Summary);
4238 
4239   writeFunctionTypeMetadataRecords(
4240       Stream, FS, [&](const ValueInfo &VI) -> std::optional<unsigned> {
4241         return {VE.getValueID(VI.getValue())};
4242       });
4243 
4244   writeFunctionHeapProfileRecords(
4245       Stream, FS, CallsiteAbbrev, AllocAbbrev,
4246       /*PerModule*/ true,
4247       /*GetValueId*/ [&](const ValueInfo &VI) { return getValueId(VI); },
4248       /*GetStackIndex*/ [&](unsigned I) { return I; });
4249 
4250   auto SpecialRefCnts = FS->specialRefCounts();
4251   NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
4252   NameVals.push_back(FS->instCount());
4253   NameVals.push_back(getEncodedFFlags(FS->fflags()));
4254   NameVals.push_back(FS->refs().size());
4255   NameVals.push_back(SpecialRefCnts.first);  // rorefcnt
4256   NameVals.push_back(SpecialRefCnts.second); // worefcnt
4257 
4258   for (auto &RI : FS->refs())
4259     NameVals.push_back(getValueId(RI));
4260 
4261   const bool UseRelBFRecord =
4262       WriteRelBFToSummary && !F.hasProfileData() &&
4263       ForceSummaryEdgesCold == FunctionSummary::FSHT_None;
4264   for (auto &ECI : FS->calls()) {
4265     NameVals.push_back(getValueId(ECI.first));
4266     if (UseRelBFRecord)
4267       NameVals.push_back(getEncodedRelBFCallEdgeInfo(ECI.second));
4268     else
4269       NameVals.push_back(getEncodedHotnessCallEdgeInfo(ECI.second));
4270   }
4271 
4272   unsigned FSAbbrev =
4273       (UseRelBFRecord ? FSCallsRelBFAbbrev : FSCallsProfileAbbrev);
4274   unsigned Code =
4275       (UseRelBFRecord ? bitc::FS_PERMODULE_RELBF : bitc::FS_PERMODULE_PROFILE);
4276 
4277   // Emit the finished record.
4278   Stream.EmitRecord(Code, NameVals, FSAbbrev);
4279   NameVals.clear();
4280 }
4281 
4282 // Collect the global value references in the given variable's initializer,
4283 // and emit them in a summary record.
4284 void ModuleBitcodeWriterBase::writeModuleLevelReferences(
4285     const GlobalVariable &V, SmallVector<uint64_t, 64> &NameVals,
4286     unsigned FSModRefsAbbrev, unsigned FSModVTableRefsAbbrev) {
4287   auto VI = Index->getValueInfo(V.getGUID());
4288   if (!VI || VI.getSummaryList().empty()) {
4289     // Only declarations should not have a summary (a declaration might however
4290     // have a summary if the def was in module level asm).
4291     assert(V.isDeclaration());
4292     return;
4293   }
4294   auto *Summary = VI.getSummaryList()[0].get();
4295   NameVals.push_back(VE.getValueID(&V));
4296   GlobalVarSummary *VS = cast<GlobalVarSummary>(Summary);
4297   NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
4298   NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
4299 
4300   auto VTableFuncs = VS->vTableFuncs();
4301   if (!VTableFuncs.empty())
4302     NameVals.push_back(VS->refs().size());
4303 
4304   unsigned SizeBeforeRefs = NameVals.size();
4305   for (auto &RI : VS->refs())
4306     NameVals.push_back(VE.getValueID(RI.getValue()));
4307   // Sort the refs for determinism output, the vector returned by FS->refs() has
4308   // been initialized from a DenseSet.
4309   llvm::sort(drop_begin(NameVals, SizeBeforeRefs));
4310 
4311   if (VTableFuncs.empty())
4312     Stream.EmitRecord(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS, NameVals,
4313                       FSModRefsAbbrev);
4314   else {
4315     // VTableFuncs pairs should already be sorted by offset.
4316     for (auto &P : VTableFuncs) {
4317       NameVals.push_back(VE.getValueID(P.FuncVI.getValue()));
4318       NameVals.push_back(P.VTableOffset);
4319     }
4320 
4321     Stream.EmitRecord(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS, NameVals,
4322                       FSModVTableRefsAbbrev);
4323   }
4324   NameVals.clear();
4325 }
4326 
4327 /// Emit the per-module summary section alongside the rest of
4328 /// the module's bitcode.
4329 void ModuleBitcodeWriterBase::writePerModuleGlobalValueSummary() {
4330   // By default we compile with ThinLTO if the module has a summary, but the
4331   // client can request full LTO with a module flag.
4332   bool IsThinLTO = true;
4333   if (auto *MD =
4334           mdconst::extract_or_null<ConstantInt>(M.getModuleFlag("ThinLTO")))
4335     IsThinLTO = MD->getZExtValue();
4336   Stream.EnterSubblock(IsThinLTO ? bitc::GLOBALVAL_SUMMARY_BLOCK_ID
4337                                  : bitc::FULL_LTO_GLOBALVAL_SUMMARY_BLOCK_ID,
4338                        4);
4339 
4340   Stream.EmitRecord(
4341       bitc::FS_VERSION,
4342       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
4343 
4344   // Write the index flags.
4345   uint64_t Flags = 0;
4346   // Bits 1-3 are set only in the combined index, skip them.
4347   if (Index->enableSplitLTOUnit())
4348     Flags |= 0x8;
4349   if (Index->hasUnifiedLTO())
4350     Flags |= 0x200;
4351 
4352   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Flags});
4353 
4354   if (Index->begin() == Index->end()) {
4355     Stream.ExitBlock();
4356     return;
4357   }
4358 
4359   auto Abbv = std::make_shared<BitCodeAbbrev>();
4360   Abbv->Add(BitCodeAbbrevOp(bitc::FS_VALUE_GUID));
4361   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
4362   // GUIDS often use up most of 64-bits, so encode as two Fixed 32.
4363   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
4364   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
4365   unsigned ValueGuidAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4366 
4367   for (const auto &GVI : valueIds()) {
4368     Stream.EmitRecord(bitc::FS_VALUE_GUID,
4369                       ArrayRef<uint32_t>{GVI.second,
4370                                          static_cast<uint32_t>(GVI.first >> 32),
4371                                          static_cast<uint32_t>(GVI.first)},
4372                       ValueGuidAbbrev);
4373   }
4374 
4375   if (!Index->stackIds().empty()) {
4376     auto StackIdAbbv = std::make_shared<BitCodeAbbrev>();
4377     StackIdAbbv->Add(BitCodeAbbrevOp(bitc::FS_STACK_IDS));
4378     // numids x stackid
4379     StackIdAbbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4380     StackIdAbbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4381     unsigned StackIdAbbvId = Stream.EmitAbbrev(std::move(StackIdAbbv));
4382     Stream.EmitRecord(bitc::FS_STACK_IDS, Index->stackIds(), StackIdAbbvId);
4383   }
4384 
4385   // Abbrev for FS_PERMODULE_PROFILE.
4386   Abbv = std::make_shared<BitCodeAbbrev>();
4387   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_PROFILE));
4388   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4389   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // flags
4390   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4391   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4392   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4393   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4394   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4395   // numrefs x valueid, n x (valueid, hotness+tailcall flags)
4396   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4397   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4398   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4399 
4400   // Abbrev for FS_PERMODULE_RELBF.
4401   Abbv = std::make_shared<BitCodeAbbrev>();
4402   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_RELBF));
4403   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4404   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4405   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4406   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4407   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4408   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4409   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4410   // numrefs x valueid, n x (valueid, rel_block_freq+tailcall])
4411   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4412   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4413   unsigned FSCallsRelBFAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4414 
4415   // Abbrev for FS_PERMODULE_GLOBALVAR_INIT_REFS.
4416   Abbv = std::make_shared<BitCodeAbbrev>();
4417   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS));
4418   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
4419   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
4420   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));  // valueids
4421   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4422   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4423 
4424   // Abbrev for FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS.
4425   Abbv = std::make_shared<BitCodeAbbrev>();
4426   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS));
4427   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
4428   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
4429   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numrefs
4430   // numrefs x valueid, n x (valueid , offset)
4431   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4432   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4433   unsigned FSModVTableRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4434 
4435   // Abbrev for FS_ALIAS.
4436   Abbv = std::make_shared<BitCodeAbbrev>();
4437   Abbv->Add(BitCodeAbbrevOp(bitc::FS_ALIAS));
4438   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4439   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4440   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4441   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4442 
4443   // Abbrev for FS_TYPE_ID_METADATA
4444   Abbv = std::make_shared<BitCodeAbbrev>();
4445   Abbv->Add(BitCodeAbbrevOp(bitc::FS_TYPE_ID_METADATA));
4446   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid strtab index
4447   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid length
4448   // n x (valueid , offset)
4449   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4450   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4451   unsigned TypeIdCompatibleVtableAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4452 
4453   Abbv = std::make_shared<BitCodeAbbrev>();
4454   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_CALLSITE_INFO));
4455   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
4456   // n x stackidindex
4457   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4458   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4459   unsigned CallsiteAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4460 
4461   Abbv = std::make_shared<BitCodeAbbrev>();
4462   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_ALLOC_INFO));
4463   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // nummib
4464   // n x (alloc type, numstackids, numstackids x stackidindex)
4465   // optional: nummib x total size
4466   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4467   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4468   unsigned AllocAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4469 
4470   SmallVector<uint64_t, 64> NameVals;
4471   // Iterate over the list of functions instead of the Index to
4472   // ensure the ordering is stable.
4473   for (const Function &F : M) {
4474     // Summary emission does not support anonymous functions, they have to
4475     // renamed using the anonymous function renaming pass.
4476     if (!F.hasName())
4477       report_fatal_error("Unexpected anonymous function when writing summary");
4478 
4479     ValueInfo VI = Index->getValueInfo(F.getGUID());
4480     if (!VI || VI.getSummaryList().empty()) {
4481       // Only declarations should not have a summary (a declaration might
4482       // however have a summary if the def was in module level asm).
4483       assert(F.isDeclaration());
4484       continue;
4485     }
4486     auto *Summary = VI.getSummaryList()[0].get();
4487     writePerModuleFunctionSummaryRecord(
4488         NameVals, Summary, VE.getValueID(&F), FSCallsRelBFAbbrev,
4489         FSCallsProfileAbbrev, CallsiteAbbrev, AllocAbbrev, F);
4490   }
4491 
4492   // Capture references from GlobalVariable initializers, which are outside
4493   // of a function scope.
4494   for (const GlobalVariable &G : M.globals())
4495     writeModuleLevelReferences(G, NameVals, FSModRefsAbbrev,
4496                                FSModVTableRefsAbbrev);
4497 
4498   for (const GlobalAlias &A : M.aliases()) {
4499     auto *Aliasee = A.getAliaseeObject();
4500     // Skip ifunc and nameless functions which don't have an entry in the
4501     // summary.
4502     if (!Aliasee->hasName() || isa<GlobalIFunc>(Aliasee))
4503       continue;
4504     auto AliasId = VE.getValueID(&A);
4505     auto AliaseeId = VE.getValueID(Aliasee);
4506     NameVals.push_back(AliasId);
4507     auto *Summary = Index->getGlobalValueSummary(A);
4508     AliasSummary *AS = cast<AliasSummary>(Summary);
4509     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
4510     NameVals.push_back(AliaseeId);
4511     Stream.EmitRecord(bitc::FS_ALIAS, NameVals, FSAliasAbbrev);
4512     NameVals.clear();
4513   }
4514 
4515   for (auto &S : Index->typeIdCompatibleVtableMap()) {
4516     writeTypeIdCompatibleVtableSummaryRecord(NameVals, StrtabBuilder, S.first,
4517                                              S.second, VE);
4518     Stream.EmitRecord(bitc::FS_TYPE_ID_METADATA, NameVals,
4519                       TypeIdCompatibleVtableAbbrev);
4520     NameVals.clear();
4521   }
4522 
4523   if (Index->getBlockCount())
4524     Stream.EmitRecord(bitc::FS_BLOCK_COUNT,
4525                       ArrayRef<uint64_t>{Index->getBlockCount()});
4526 
4527   Stream.ExitBlock();
4528 }
4529 
4530 /// Emit the combined summary section into the combined index file.
4531 void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
4532   Stream.EnterSubblock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID, 4);
4533   Stream.EmitRecord(
4534       bitc::FS_VERSION,
4535       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
4536 
4537   // Write the index flags.
4538   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Index.getFlags()});
4539 
4540   auto Abbv = std::make_shared<BitCodeAbbrev>();
4541   Abbv->Add(BitCodeAbbrevOp(bitc::FS_VALUE_GUID));
4542   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
4543   // GUIDS often use up most of 64-bits, so encode as two Fixed 32.
4544   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
4545   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
4546   unsigned ValueGuidAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4547 
4548   for (const auto &GVI : valueIds()) {
4549     Stream.EmitRecord(bitc::FS_VALUE_GUID,
4550                       ArrayRef<uint32_t>{GVI.second,
4551                                          static_cast<uint32_t>(GVI.first >> 32),
4552                                          static_cast<uint32_t>(GVI.first)},
4553                       ValueGuidAbbrev);
4554   }
4555 
4556   // Write the stack ids used by this index, which will be a subset of those in
4557   // the full index in the case of distributed indexes.
4558   if (!StackIds.empty()) {
4559     auto StackIdAbbv = std::make_shared<BitCodeAbbrev>();
4560     StackIdAbbv->Add(BitCodeAbbrevOp(bitc::FS_STACK_IDS));
4561     // numids x stackid
4562     StackIdAbbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4563     StackIdAbbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4564     unsigned StackIdAbbvId = Stream.EmitAbbrev(std::move(StackIdAbbv));
4565     Stream.EmitRecord(bitc::FS_STACK_IDS, StackIds, StackIdAbbvId);
4566   }
4567 
4568   // Abbrev for FS_COMBINED_PROFILE.
4569   Abbv = std::make_shared<BitCodeAbbrev>();
4570   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_PROFILE));
4571   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4572   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4573   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4574   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4575   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4576   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
4577   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4578   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4579   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4580   // numrefs x valueid, n x (valueid, hotness+tailcall flags)
4581   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4582   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4583   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4584 
4585   // Abbrev for FS_COMBINED_GLOBALVAR_INIT_REFS.
4586   Abbv = std::make_shared<BitCodeAbbrev>();
4587   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS));
4588   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4589   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4590   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4591   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));    // valueids
4592   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4593   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4594 
4595   // Abbrev for FS_COMBINED_ALIAS.
4596   Abbv = std::make_shared<BitCodeAbbrev>();
4597   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_ALIAS));
4598   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4599   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4600   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4601   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4602   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4603 
4604   Abbv = std::make_shared<BitCodeAbbrev>();
4605   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_CALLSITE_INFO));
4606   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
4607   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numstackindices
4608   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numver
4609   // numstackindices x stackidindex, numver x version
4610   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4611   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4612   unsigned CallsiteAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4613 
4614   Abbv = std::make_shared<BitCodeAbbrev>();
4615   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_ALLOC_INFO));
4616   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // nummib
4617   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numver
4618   // nummib x (alloc type, numstackids, numstackids x stackidindex),
4619   // numver x version
4620   // optional: nummib x total size
4621   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4622   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4623   unsigned AllocAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4624 
4625   auto shouldImportValueAsDecl = [&](GlobalValueSummary *GVS) -> bool {
4626     if (DecSummaries == nullptr)
4627       return false;
4628     return DecSummaries->count(GVS);
4629   };
4630 
4631   // The aliases are emitted as a post-pass, and will point to the value
4632   // id of the aliasee. Save them in a vector for post-processing.
4633   SmallVector<AliasSummary *, 64> Aliases;
4634 
4635   // Save the value id for each summary for alias emission.
4636   DenseMap<const GlobalValueSummary *, unsigned> SummaryToValueIdMap;
4637 
4638   SmallVector<uint64_t, 64> NameVals;
4639 
4640   // Set that will be populated during call to writeFunctionTypeMetadataRecords
4641   // with the type ids referenced by this index file.
4642   std::set<GlobalValue::GUID> ReferencedTypeIds;
4643 
4644   // For local linkage, we also emit the original name separately
4645   // immediately after the record.
4646   auto MaybeEmitOriginalName = [&](GlobalValueSummary &S) {
4647     // We don't need to emit the original name if we are writing the index for
4648     // distributed backends (in which case ModuleToSummariesForIndex is
4649     // non-null). The original name is only needed during the thin link, since
4650     // for SamplePGO the indirect call targets for local functions have
4651     // have the original name annotated in profile.
4652     // Continue to emit it when writing out the entire combined index, which is
4653     // used in testing the thin link via llvm-lto.
4654     if (ModuleToSummariesForIndex || !GlobalValue::isLocalLinkage(S.linkage()))
4655       return;
4656     NameVals.push_back(S.getOriginalName());
4657     Stream.EmitRecord(bitc::FS_COMBINED_ORIGINAL_NAME, NameVals);
4658     NameVals.clear();
4659   };
4660 
4661   DenseSet<GlobalValue::GUID> DefOrUseGUIDs;
4662   forEachSummary([&](GVInfo I, bool IsAliasee) {
4663     GlobalValueSummary *S = I.second;
4664     assert(S);
4665     DefOrUseGUIDs.insert(I.first);
4666     for (const ValueInfo &VI : S->refs())
4667       DefOrUseGUIDs.insert(VI.getGUID());
4668 
4669     auto ValueId = getValueId(I.first);
4670     assert(ValueId);
4671     SummaryToValueIdMap[S] = *ValueId;
4672 
4673     // If this is invoked for an aliasee, we want to record the above
4674     // mapping, but then not emit a summary entry (if the aliasee is
4675     // to be imported, we will invoke this separately with IsAliasee=false).
4676     if (IsAliasee)
4677       return;
4678 
4679     if (auto *AS = dyn_cast<AliasSummary>(S)) {
4680       // Will process aliases as a post-pass because the reader wants all
4681       // global to be loaded first.
4682       Aliases.push_back(AS);
4683       return;
4684     }
4685 
4686     if (auto *VS = dyn_cast<GlobalVarSummary>(S)) {
4687       NameVals.push_back(*ValueId);
4688       assert(ModuleIdMap.count(VS->modulePath()));
4689       NameVals.push_back(ModuleIdMap[VS->modulePath()]);
4690       NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
4691       NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
4692       for (auto &RI : VS->refs()) {
4693         auto RefValueId = getValueId(RI.getGUID());
4694         if (!RefValueId)
4695           continue;
4696         NameVals.push_back(*RefValueId);
4697       }
4698 
4699       // Emit the finished record.
4700       Stream.EmitRecord(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS, NameVals,
4701                         FSModRefsAbbrev);
4702       NameVals.clear();
4703       MaybeEmitOriginalName(*S);
4704       return;
4705     }
4706 
4707     auto GetValueId = [&](const ValueInfo &VI) -> std::optional<unsigned> {
4708       if (!VI)
4709         return std::nullopt;
4710       return getValueId(VI.getGUID());
4711     };
4712 
4713     auto *FS = cast<FunctionSummary>(S);
4714     writeFunctionTypeMetadataRecords(Stream, FS, GetValueId);
4715     getReferencedTypeIds(FS, ReferencedTypeIds);
4716 
4717     writeFunctionHeapProfileRecords(
4718         Stream, FS, CallsiteAbbrev, AllocAbbrev,
4719         /*PerModule*/ false,
4720         /*GetValueId*/
4721         [&](const ValueInfo &VI) -> unsigned {
4722           std::optional<unsigned> ValueID = GetValueId(VI);
4723           // This can happen in shared index files for distributed ThinLTO if
4724           // the callee function summary is not included. Record 0 which we
4725           // will have to deal with conservatively when doing any kind of
4726           // validation in the ThinLTO backends.
4727           if (!ValueID)
4728             return 0;
4729           return *ValueID;
4730         },
4731         /*GetStackIndex*/
4732         [&](unsigned I) {
4733           // Get the corresponding index into the list of StackIds actually
4734           // being written for this combined index (which may be a subset in
4735           // the case of distributed indexes).
4736           assert(StackIdIndicesToIndex.contains(I));
4737           return StackIdIndicesToIndex[I];
4738         });
4739 
4740     NameVals.push_back(*ValueId);
4741     assert(ModuleIdMap.count(FS->modulePath()));
4742     NameVals.push_back(ModuleIdMap[FS->modulePath()]);
4743     NameVals.push_back(
4744         getEncodedGVSummaryFlags(FS->flags(), shouldImportValueAsDecl(FS)));
4745     NameVals.push_back(FS->instCount());
4746     NameVals.push_back(getEncodedFFlags(FS->fflags()));
4747     // TODO: Stop writing entry count and bump bitcode version.
4748     NameVals.push_back(0 /* EntryCount */);
4749 
4750     // Fill in below
4751     NameVals.push_back(0); // numrefs
4752     NameVals.push_back(0); // rorefcnt
4753     NameVals.push_back(0); // worefcnt
4754 
4755     unsigned Count = 0, RORefCnt = 0, WORefCnt = 0;
4756     for (auto &RI : FS->refs()) {
4757       auto RefValueId = getValueId(RI.getGUID());
4758       if (!RefValueId)
4759         continue;
4760       NameVals.push_back(*RefValueId);
4761       if (RI.isReadOnly())
4762         RORefCnt++;
4763       else if (RI.isWriteOnly())
4764         WORefCnt++;
4765       Count++;
4766     }
4767     NameVals[6] = Count;
4768     NameVals[7] = RORefCnt;
4769     NameVals[8] = WORefCnt;
4770 
4771     for (auto &EI : FS->calls()) {
4772       // If this GUID doesn't have a value id, it doesn't have a function
4773       // summary and we don't need to record any calls to it.
4774       std::optional<unsigned> CallValueId = GetValueId(EI.first);
4775       if (!CallValueId)
4776         continue;
4777       NameVals.push_back(*CallValueId);
4778       NameVals.push_back(getEncodedHotnessCallEdgeInfo(EI.second));
4779     }
4780 
4781     // Emit the finished record.
4782     Stream.EmitRecord(bitc::FS_COMBINED_PROFILE, NameVals,
4783                       FSCallsProfileAbbrev);
4784     NameVals.clear();
4785     MaybeEmitOriginalName(*S);
4786   });
4787 
4788   for (auto *AS : Aliases) {
4789     auto AliasValueId = SummaryToValueIdMap[AS];
4790     assert(AliasValueId);
4791     NameVals.push_back(AliasValueId);
4792     assert(ModuleIdMap.count(AS->modulePath()));
4793     NameVals.push_back(ModuleIdMap[AS->modulePath()]);
4794     NameVals.push_back(
4795         getEncodedGVSummaryFlags(AS->flags(), shouldImportValueAsDecl(AS)));
4796     auto AliaseeValueId = SummaryToValueIdMap[&AS->getAliasee()];
4797     assert(AliaseeValueId);
4798     NameVals.push_back(AliaseeValueId);
4799 
4800     // Emit the finished record.
4801     Stream.EmitRecord(bitc::FS_COMBINED_ALIAS, NameVals, FSAliasAbbrev);
4802     NameVals.clear();
4803     MaybeEmitOriginalName(*AS);
4804 
4805     if (auto *FS = dyn_cast<FunctionSummary>(&AS->getAliasee()))
4806       getReferencedTypeIds(FS, ReferencedTypeIds);
4807   }
4808 
4809   if (!Index.cfiFunctionDefs().empty()) {
4810     for (auto &S : Index.cfiFunctionDefs()) {
4811       if (DefOrUseGUIDs.contains(
4812               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4813         NameVals.push_back(StrtabBuilder.add(S));
4814         NameVals.push_back(S.size());
4815       }
4816     }
4817     if (!NameVals.empty()) {
4818       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DEFS, NameVals);
4819       NameVals.clear();
4820     }
4821   }
4822 
4823   if (!Index.cfiFunctionDecls().empty()) {
4824     for (auto &S : Index.cfiFunctionDecls()) {
4825       if (DefOrUseGUIDs.contains(
4826               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4827         NameVals.push_back(StrtabBuilder.add(S));
4828         NameVals.push_back(S.size());
4829       }
4830     }
4831     if (!NameVals.empty()) {
4832       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DECLS, NameVals);
4833       NameVals.clear();
4834     }
4835   }
4836 
4837   // Walk the GUIDs that were referenced, and write the
4838   // corresponding type id records.
4839   for (auto &T : ReferencedTypeIds) {
4840     auto TidIter = Index.typeIds().equal_range(T);
4841     for (const auto &[GUID, TypeIdPair] : make_range(TidIter)) {
4842       writeTypeIdSummaryRecord(NameVals, StrtabBuilder, TypeIdPair.first,
4843                                TypeIdPair.second);
4844       Stream.EmitRecord(bitc::FS_TYPE_ID, NameVals);
4845       NameVals.clear();
4846     }
4847   }
4848 
4849   if (Index.getBlockCount())
4850     Stream.EmitRecord(bitc::FS_BLOCK_COUNT,
4851                       ArrayRef<uint64_t>{Index.getBlockCount()});
4852 
4853   Stream.ExitBlock();
4854 }
4855 
4856 /// Create the "IDENTIFICATION_BLOCK_ID" containing a single string with the
4857 /// current llvm version, and a record for the epoch number.
4858 static void writeIdentificationBlock(BitstreamWriter &Stream) {
4859   Stream.EnterSubblock(bitc::IDENTIFICATION_BLOCK_ID, 5);
4860 
4861   // Write the "user readable" string identifying the bitcode producer
4862   auto Abbv = std::make_shared<BitCodeAbbrev>();
4863   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_STRING));
4864   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4865   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
4866   auto StringAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4867   writeStringRecord(Stream, bitc::IDENTIFICATION_CODE_STRING,
4868                     "LLVM" LLVM_VERSION_STRING, StringAbbrev);
4869 
4870   // Write the epoch version
4871   Abbv = std::make_shared<BitCodeAbbrev>();
4872   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_EPOCH));
4873   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
4874   auto EpochAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4875   constexpr std::array<unsigned, 1> Vals = {{bitc::BITCODE_CURRENT_EPOCH}};
4876   Stream.EmitRecord(bitc::IDENTIFICATION_CODE_EPOCH, Vals, EpochAbbrev);
4877   Stream.ExitBlock();
4878 }
4879 
4880 void ModuleBitcodeWriter::writeModuleHash(StringRef View) {
4881   // Emit the module's hash.
4882   // MODULE_CODE_HASH: [5*i32]
4883   if (GenerateHash) {
4884     uint32_t Vals[5];
4885     Hasher.update(ArrayRef<uint8_t>(
4886         reinterpret_cast<const uint8_t *>(View.data()), View.size()));
4887     std::array<uint8_t, 20> Hash = Hasher.result();
4888     for (int Pos = 0; Pos < 20; Pos += 4) {
4889       Vals[Pos / 4] = support::endian::read32be(Hash.data() + Pos);
4890     }
4891 
4892     // Emit the finished record.
4893     Stream.EmitRecord(bitc::MODULE_CODE_HASH, Vals);
4894 
4895     if (ModHash)
4896       // Save the written hash value.
4897       llvm::copy(Vals, std::begin(*ModHash));
4898   }
4899 }
4900 
4901 void ModuleBitcodeWriter::write() {
4902   writeIdentificationBlock(Stream);
4903 
4904   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4905   // We will want to write the module hash at this point. Block any flushing so
4906   // we can have access to the whole underlying data later.
4907   Stream.markAndBlockFlushing();
4908 
4909   writeModuleVersion();
4910 
4911   // Emit blockinfo, which defines the standard abbreviations etc.
4912   writeBlockInfo();
4913 
4914   // Emit information describing all of the types in the module.
4915   writeTypeTable();
4916 
4917   // Emit information about attribute groups.
4918   writeAttributeGroupTable();
4919 
4920   // Emit information about parameter attributes.
4921   writeAttributeTable();
4922 
4923   writeComdats();
4924 
4925   // Emit top-level description of module, including target triple, inline asm,
4926   // descriptors for global variables, and function prototype info.
4927   writeModuleInfo();
4928 
4929   // Emit constants.
4930   writeModuleConstants();
4931 
4932   // Emit metadata kind names.
4933   writeModuleMetadataKinds();
4934 
4935   // Emit metadata.
4936   writeModuleMetadata();
4937 
4938   // Emit module-level use-lists.
4939   if (VE.shouldPreserveUseListOrder())
4940     writeUseListBlock(nullptr);
4941 
4942   writeOperandBundleTags();
4943   writeSyncScopeNames();
4944 
4945   // Emit function bodies.
4946   DenseMap<const Function *, uint64_t> FunctionToBitcodeIndex;
4947   for (const Function &F : M)
4948     if (!F.isDeclaration())
4949       writeFunction(F, FunctionToBitcodeIndex);
4950 
4951   // Need to write after the above call to WriteFunction which populates
4952   // the summary information in the index.
4953   if (Index)
4954     writePerModuleGlobalValueSummary();
4955 
4956   writeGlobalValueSymbolTable(FunctionToBitcodeIndex);
4957 
4958   writeModuleHash(Stream.getMarkedBufferAndResumeFlushing());
4959 
4960   Stream.ExitBlock();
4961 }
4962 
4963 static void writeInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
4964                                uint32_t &Position) {
4965   support::endian::write32le(&Buffer[Position], Value);
4966   Position += 4;
4967 }
4968 
4969 /// If generating a bc file on darwin, we have to emit a
4970 /// header and trailer to make it compatible with the system archiver.  To do
4971 /// this we emit the following header, and then emit a trailer that pads the
4972 /// file out to be a multiple of 16 bytes.
4973 ///
4974 /// struct bc_header {
4975 ///   uint32_t Magic;         // 0x0B17C0DE
4976 ///   uint32_t Version;       // Version, currently always 0.
4977 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
4978 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
4979 ///   uint32_t CPUType;       // CPU specifier.
4980 ///   ... potentially more later ...
4981 /// };
4982 static void emitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
4983                                          const Triple &TT) {
4984   unsigned CPUType = ~0U;
4985 
4986   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
4987   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
4988   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
4989   // specific constants here because they are implicitly part of the Darwin ABI.
4990   enum {
4991     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
4992     DARWIN_CPU_TYPE_X86        = 7,
4993     DARWIN_CPU_TYPE_ARM        = 12,
4994     DARWIN_CPU_TYPE_POWERPC    = 18
4995   };
4996 
4997   Triple::ArchType Arch = TT.getArch();
4998   if (Arch == Triple::x86_64)
4999     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
5000   else if (Arch == Triple::x86)
5001     CPUType = DARWIN_CPU_TYPE_X86;
5002   else if (Arch == Triple::ppc)
5003     CPUType = DARWIN_CPU_TYPE_POWERPC;
5004   else if (Arch == Triple::ppc64)
5005     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
5006   else if (Arch == Triple::arm || Arch == Triple::thumb)
5007     CPUType = DARWIN_CPU_TYPE_ARM;
5008 
5009   // Traditional Bitcode starts after header.
5010   assert(Buffer.size() >= BWH_HeaderSize &&
5011          "Expected header size to be reserved");
5012   unsigned BCOffset = BWH_HeaderSize;
5013   unsigned BCSize = Buffer.size() - BWH_HeaderSize;
5014 
5015   // Write the magic and version.
5016   unsigned Position = 0;
5017   writeInt32ToBuffer(0x0B17C0DE, Buffer, Position);
5018   writeInt32ToBuffer(0, Buffer, Position); // Version.
5019   writeInt32ToBuffer(BCOffset, Buffer, Position);
5020   writeInt32ToBuffer(BCSize, Buffer, Position);
5021   writeInt32ToBuffer(CPUType, Buffer, Position);
5022 
5023   // If the file is not a multiple of 16 bytes, insert dummy padding.
5024   while (Buffer.size() & 15)
5025     Buffer.push_back(0);
5026 }
5027 
5028 /// Helper to write the header common to all bitcode files.
5029 static void writeBitcodeHeader(BitstreamWriter &Stream) {
5030   // Emit the file header.
5031   Stream.Emit((unsigned)'B', 8);
5032   Stream.Emit((unsigned)'C', 8);
5033   Stream.Emit(0x0, 4);
5034   Stream.Emit(0xC, 4);
5035   Stream.Emit(0xE, 4);
5036   Stream.Emit(0xD, 4);
5037 }
5038 
5039 BitcodeWriter::BitcodeWriter(SmallVectorImpl<char> &Buffer)
5040     : Stream(new BitstreamWriter(Buffer)) {
5041   writeBitcodeHeader(*Stream);
5042 }
5043 
5044 BitcodeWriter::BitcodeWriter(raw_ostream &FS)
5045     : Stream(new BitstreamWriter(FS, FlushThreshold)) {
5046   writeBitcodeHeader(*Stream);
5047 }
5048 
5049 BitcodeWriter::~BitcodeWriter() { assert(WroteStrtab); }
5050 
5051 void BitcodeWriter::writeBlob(unsigned Block, unsigned Record, StringRef Blob) {
5052   Stream->EnterSubblock(Block, 3);
5053 
5054   auto Abbv = std::make_shared<BitCodeAbbrev>();
5055   Abbv->Add(BitCodeAbbrevOp(Record));
5056   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
5057   auto AbbrevNo = Stream->EmitAbbrev(std::move(Abbv));
5058 
5059   Stream->EmitRecordWithBlob(AbbrevNo, ArrayRef<uint64_t>{Record}, Blob);
5060 
5061   Stream->ExitBlock();
5062 }
5063 
5064 void BitcodeWriter::writeSymtab() {
5065   assert(!WroteStrtab && !WroteSymtab);
5066 
5067   // If any module has module-level inline asm, we will require a registered asm
5068   // parser for the target so that we can create an accurate symbol table for
5069   // the module.
5070   for (Module *M : Mods) {
5071     if (M->getModuleInlineAsm().empty())
5072       continue;
5073 
5074     std::string Err;
5075     const Triple TT(M->getTargetTriple());
5076     const Target *T = TargetRegistry::lookupTarget(TT.str(), Err);
5077     if (!T || !T->hasMCAsmParser())
5078       return;
5079   }
5080 
5081   WroteSymtab = true;
5082   SmallVector<char, 0> Symtab;
5083   // The irsymtab::build function may be unable to create a symbol table if the
5084   // module is malformed (e.g. it contains an invalid alias). Writing a symbol
5085   // table is not required for correctness, but we still want to be able to
5086   // write malformed modules to bitcode files, so swallow the error.
5087   if (Error E = irsymtab::build(Mods, Symtab, StrtabBuilder, Alloc)) {
5088     consumeError(std::move(E));
5089     return;
5090   }
5091 
5092   writeBlob(bitc::SYMTAB_BLOCK_ID, bitc::SYMTAB_BLOB,
5093             {Symtab.data(), Symtab.size()});
5094 }
5095 
5096 void BitcodeWriter::writeStrtab() {
5097   assert(!WroteStrtab);
5098 
5099   std::vector<char> Strtab;
5100   StrtabBuilder.finalizeInOrder();
5101   Strtab.resize(StrtabBuilder.getSize());
5102   StrtabBuilder.write((uint8_t *)Strtab.data());
5103 
5104   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB,
5105             {Strtab.data(), Strtab.size()});
5106 
5107   WroteStrtab = true;
5108 }
5109 
5110 void BitcodeWriter::copyStrtab(StringRef Strtab) {
5111   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB, Strtab);
5112   WroteStrtab = true;
5113 }
5114 
5115 void BitcodeWriter::writeModule(const Module &M,
5116                                 bool ShouldPreserveUseListOrder,
5117                                 const ModuleSummaryIndex *Index,
5118                                 bool GenerateHash, ModuleHash *ModHash) {
5119   assert(!WroteStrtab);
5120 
5121   // The Mods vector is used by irsymtab::build, which requires non-const
5122   // Modules in case it needs to materialize metadata. But the bitcode writer
5123   // requires that the module is materialized, so we can cast to non-const here,
5124   // after checking that it is in fact materialized.
5125   assert(M.isMaterialized());
5126   Mods.push_back(const_cast<Module *>(&M));
5127 
5128   ModuleBitcodeWriter ModuleWriter(M, StrtabBuilder, *Stream,
5129                                    ShouldPreserveUseListOrder, Index,
5130                                    GenerateHash, ModHash);
5131   ModuleWriter.write();
5132 }
5133 
5134 void BitcodeWriter::writeIndex(
5135     const ModuleSummaryIndex *Index,
5136     const ModuleToSummariesForIndexTy *ModuleToSummariesForIndex,
5137     const GVSummaryPtrSet *DecSummaries) {
5138   IndexBitcodeWriter IndexWriter(*Stream, StrtabBuilder, *Index, DecSummaries,
5139                                  ModuleToSummariesForIndex);
5140   IndexWriter.write();
5141 }
5142 
5143 /// Write the specified module to the specified output stream.
5144 void llvm::WriteBitcodeToFile(const Module &M, raw_ostream &Out,
5145                               bool ShouldPreserveUseListOrder,
5146                               const ModuleSummaryIndex *Index,
5147                               bool GenerateHash, ModuleHash *ModHash) {
5148   auto Write = [&](BitcodeWriter &Writer) {
5149     Writer.writeModule(M, ShouldPreserveUseListOrder, Index, GenerateHash,
5150                        ModHash);
5151     Writer.writeSymtab();
5152     Writer.writeStrtab();
5153   };
5154   Triple TT(M.getTargetTriple());
5155   if (TT.isOSDarwin() || TT.isOSBinFormatMachO()) {
5156     // If this is darwin or another generic macho target, reserve space for the
5157     // header. Note that the header is computed *after* the output is known, so
5158     // we currently explicitly use a buffer, write to it, and then subsequently
5159     // flush to Out.
5160     SmallVector<char, 0> Buffer;
5161     Buffer.reserve(256 * 1024);
5162     Buffer.insert(Buffer.begin(), BWH_HeaderSize, 0);
5163     BitcodeWriter Writer(Buffer);
5164     Write(Writer);
5165     emitDarwinBCHeaderAndTrailer(Buffer, TT);
5166     Out.write(Buffer.data(), Buffer.size());
5167   } else {
5168     BitcodeWriter Writer(Out);
5169     Write(Writer);
5170   }
5171 }
5172 
5173 void IndexBitcodeWriter::write() {
5174   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
5175 
5176   writeModuleVersion();
5177 
5178   // Write the module paths in the combined index.
5179   writeModStrings();
5180 
5181   // Write the summary combined index records.
5182   writeCombinedGlobalValueSummary();
5183 
5184   Stream.ExitBlock();
5185 }
5186 
5187 // Write the specified module summary index to the given raw output stream,
5188 // where it will be written in a new bitcode block. This is used when
5189 // writing the combined index file for ThinLTO. When writing a subset of the
5190 // index for a distributed backend, provide a \p ModuleToSummariesForIndex map.
5191 void llvm::writeIndexToFile(
5192     const ModuleSummaryIndex &Index, raw_ostream &Out,
5193     const ModuleToSummariesForIndexTy *ModuleToSummariesForIndex,
5194     const GVSummaryPtrSet *DecSummaries) {
5195   SmallVector<char, 0> Buffer;
5196   Buffer.reserve(256 * 1024);
5197 
5198   BitcodeWriter Writer(Buffer);
5199   Writer.writeIndex(&Index, ModuleToSummariesForIndex, DecSummaries);
5200   Writer.writeStrtab();
5201 
5202   Out.write((char *)&Buffer.front(), Buffer.size());
5203 }
5204 
5205 namespace {
5206 
5207 /// Class to manage the bitcode writing for a thin link bitcode file.
5208 class ThinLinkBitcodeWriter : public ModuleBitcodeWriterBase {
5209   /// ModHash is for use in ThinLTO incremental build, generated while writing
5210   /// the module bitcode file.
5211   const ModuleHash *ModHash;
5212 
5213 public:
5214   ThinLinkBitcodeWriter(const Module &M, StringTableBuilder &StrtabBuilder,
5215                         BitstreamWriter &Stream,
5216                         const ModuleSummaryIndex &Index,
5217                         const ModuleHash &ModHash)
5218       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
5219                                 /*ShouldPreserveUseListOrder=*/false, &Index),
5220         ModHash(&ModHash) {}
5221 
5222   void write();
5223 
5224 private:
5225   void writeSimplifiedModuleInfo();
5226 };
5227 
5228 } // end anonymous namespace
5229 
5230 // This function writes a simpilified module info for thin link bitcode file.
5231 // It only contains the source file name along with the name(the offset and
5232 // size in strtab) and linkage for global values. For the global value info
5233 // entry, in order to keep linkage at offset 5, there are three zeros used
5234 // as padding.
5235 void ThinLinkBitcodeWriter::writeSimplifiedModuleInfo() {
5236   SmallVector<unsigned, 64> Vals;
5237   // Emit the module's source file name.
5238   {
5239     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
5240     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
5241     if (Bits == SE_Char6)
5242       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
5243     else if (Bits == SE_Fixed7)
5244       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
5245 
5246     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
5247     auto Abbv = std::make_shared<BitCodeAbbrev>();
5248     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
5249     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
5250     Abbv->Add(AbbrevOpToUse);
5251     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
5252 
5253     for (const auto P : M.getSourceFileName())
5254       Vals.push_back((unsigned char)P);
5255 
5256     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
5257     Vals.clear();
5258   }
5259 
5260   // Emit the global variable information.
5261   for (const GlobalVariable &GV : M.globals()) {
5262     // GLOBALVAR: [strtab offset, strtab size, 0, 0, 0, linkage]
5263     Vals.push_back(StrtabBuilder.add(GV.getName()));
5264     Vals.push_back(GV.getName().size());
5265     Vals.push_back(0);
5266     Vals.push_back(0);
5267     Vals.push_back(0);
5268     Vals.push_back(getEncodedLinkage(GV));
5269 
5270     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals);
5271     Vals.clear();
5272   }
5273 
5274   // Emit the function proto information.
5275   for (const Function &F : M) {
5276     // FUNCTION:  [strtab offset, strtab size, 0, 0, 0, linkage]
5277     Vals.push_back(StrtabBuilder.add(F.getName()));
5278     Vals.push_back(F.getName().size());
5279     Vals.push_back(0);
5280     Vals.push_back(0);
5281     Vals.push_back(0);
5282     Vals.push_back(getEncodedLinkage(F));
5283 
5284     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals);
5285     Vals.clear();
5286   }
5287 
5288   // Emit the alias information.
5289   for (const GlobalAlias &A : M.aliases()) {
5290     // ALIAS: [strtab offset, strtab size, 0, 0, 0, linkage]
5291     Vals.push_back(StrtabBuilder.add(A.getName()));
5292     Vals.push_back(A.getName().size());
5293     Vals.push_back(0);
5294     Vals.push_back(0);
5295     Vals.push_back(0);
5296     Vals.push_back(getEncodedLinkage(A));
5297 
5298     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals);
5299     Vals.clear();
5300   }
5301 
5302   // Emit the ifunc information.
5303   for (const GlobalIFunc &I : M.ifuncs()) {
5304     // IFUNC: [strtab offset, strtab size, 0, 0, 0, linkage]
5305     Vals.push_back(StrtabBuilder.add(I.getName()));
5306     Vals.push_back(I.getName().size());
5307     Vals.push_back(0);
5308     Vals.push_back(0);
5309     Vals.push_back(0);
5310     Vals.push_back(getEncodedLinkage(I));
5311 
5312     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
5313     Vals.clear();
5314   }
5315 }
5316 
5317 void ThinLinkBitcodeWriter::write() {
5318   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
5319 
5320   writeModuleVersion();
5321 
5322   writeSimplifiedModuleInfo();
5323 
5324   writePerModuleGlobalValueSummary();
5325 
5326   // Write module hash.
5327   Stream.EmitRecord(bitc::MODULE_CODE_HASH, ArrayRef<uint32_t>(*ModHash));
5328 
5329   Stream.ExitBlock();
5330 }
5331 
5332 void BitcodeWriter::writeThinLinkBitcode(const Module &M,
5333                                          const ModuleSummaryIndex &Index,
5334                                          const ModuleHash &ModHash) {
5335   assert(!WroteStrtab);
5336 
5337   // The Mods vector is used by irsymtab::build, which requires non-const
5338   // Modules in case it needs to materialize metadata. But the bitcode writer
5339   // requires that the module is materialized, so we can cast to non-const here,
5340   // after checking that it is in fact materialized.
5341   assert(M.isMaterialized());
5342   Mods.push_back(const_cast<Module *>(&M));
5343 
5344   ThinLinkBitcodeWriter ThinLinkWriter(M, StrtabBuilder, *Stream, Index,
5345                                        ModHash);
5346   ThinLinkWriter.write();
5347 }
5348 
5349 // Write the specified thin link bitcode file to the given raw output stream,
5350 // where it will be written in a new bitcode block. This is used when
5351 // writing the per-module index file for ThinLTO.
5352 void llvm::writeThinLinkBitcodeToFile(const Module &M, raw_ostream &Out,
5353                                       const ModuleSummaryIndex &Index,
5354                                       const ModuleHash &ModHash) {
5355   SmallVector<char, 0> Buffer;
5356   Buffer.reserve(256 * 1024);
5357 
5358   BitcodeWriter Writer(Buffer);
5359   Writer.writeThinLinkBitcode(M, Index, ModHash);
5360   Writer.writeSymtab();
5361   Writer.writeStrtab();
5362 
5363   Out.write((char *)&Buffer.front(), Buffer.size());
5364 }
5365 
5366 static const char *getSectionNameForBitcode(const Triple &T) {
5367   switch (T.getObjectFormat()) {
5368   case Triple::MachO:
5369     return "__LLVM,__bitcode";
5370   case Triple::COFF:
5371   case Triple::ELF:
5372   case Triple::Wasm:
5373   case Triple::UnknownObjectFormat:
5374     return ".llvmbc";
5375   case Triple::GOFF:
5376     llvm_unreachable("GOFF is not yet implemented");
5377     break;
5378   case Triple::SPIRV:
5379     if (T.getVendor() == Triple::AMD)
5380       return ".llvmbc";
5381     llvm_unreachable("SPIRV is not yet implemented");
5382     break;
5383   case Triple::XCOFF:
5384     llvm_unreachable("XCOFF is not yet implemented");
5385     break;
5386   case Triple::DXContainer:
5387     llvm_unreachable("DXContainer is not yet implemented");
5388     break;
5389   }
5390   llvm_unreachable("Unimplemented ObjectFormatType");
5391 }
5392 
5393 static const char *getSectionNameForCommandline(const Triple &T) {
5394   switch (T.getObjectFormat()) {
5395   case Triple::MachO:
5396     return "__LLVM,__cmdline";
5397   case Triple::COFF:
5398   case Triple::ELF:
5399   case Triple::Wasm:
5400   case Triple::UnknownObjectFormat:
5401     return ".llvmcmd";
5402   case Triple::GOFF:
5403     llvm_unreachable("GOFF is not yet implemented");
5404     break;
5405   case Triple::SPIRV:
5406     if (T.getVendor() == Triple::AMD)
5407       return ".llvmcmd";
5408     llvm_unreachable("SPIRV is not yet implemented");
5409     break;
5410   case Triple::XCOFF:
5411     llvm_unreachable("XCOFF is not yet implemented");
5412     break;
5413   case Triple::DXContainer:
5414     llvm_unreachable("DXC is not yet implemented");
5415     break;
5416   }
5417   llvm_unreachable("Unimplemented ObjectFormatType");
5418 }
5419 
5420 void llvm::embedBitcodeInModule(llvm::Module &M, llvm::MemoryBufferRef Buf,
5421                                 bool EmbedBitcode, bool EmbedCmdline,
5422                                 const std::vector<uint8_t> &CmdArgs) {
5423   // Save llvm.compiler.used and remove it.
5424   SmallVector<Constant *, 2> UsedArray;
5425   SmallVector<GlobalValue *, 4> UsedGlobals;
5426   Type *UsedElementType = PointerType::getUnqual(M.getContext());
5427   GlobalVariable *Used = collectUsedGlobalVariables(M, UsedGlobals, true);
5428   for (auto *GV : UsedGlobals) {
5429     if (GV->getName() != "llvm.embedded.module" &&
5430         GV->getName() != "llvm.cmdline")
5431       UsedArray.push_back(
5432           ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
5433   }
5434   if (Used)
5435     Used->eraseFromParent();
5436 
5437   // Embed the bitcode for the llvm module.
5438   std::string Data;
5439   ArrayRef<uint8_t> ModuleData;
5440   Triple T(M.getTargetTriple());
5441 
5442   if (EmbedBitcode) {
5443     if (Buf.getBufferSize() == 0 ||
5444         !isBitcode((const unsigned char *)Buf.getBufferStart(),
5445                    (const unsigned char *)Buf.getBufferEnd())) {
5446       // If the input is LLVM Assembly, bitcode is produced by serializing
5447       // the module. Use-lists order need to be preserved in this case.
5448       llvm::raw_string_ostream OS(Data);
5449       llvm::WriteBitcodeToFile(M, OS, /* ShouldPreserveUseListOrder */ true);
5450       ModuleData =
5451           ArrayRef<uint8_t>((const uint8_t *)OS.str().data(), OS.str().size());
5452     } else
5453       // If the input is LLVM bitcode, write the input byte stream directly.
5454       ModuleData = ArrayRef<uint8_t>((const uint8_t *)Buf.getBufferStart(),
5455                                      Buf.getBufferSize());
5456   }
5457   llvm::Constant *ModuleConstant =
5458       llvm::ConstantDataArray::get(M.getContext(), ModuleData);
5459   llvm::GlobalVariable *GV = new llvm::GlobalVariable(
5460       M, ModuleConstant->getType(), true, llvm::GlobalValue::PrivateLinkage,
5461       ModuleConstant);
5462   GV->setSection(getSectionNameForBitcode(T));
5463   // Set alignment to 1 to prevent padding between two contributions from input
5464   // sections after linking.
5465   GV->setAlignment(Align(1));
5466   UsedArray.push_back(
5467       ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
5468   if (llvm::GlobalVariable *Old =
5469           M.getGlobalVariable("llvm.embedded.module", true)) {
5470     assert(Old->hasZeroLiveUses() &&
5471            "llvm.embedded.module can only be used once in llvm.compiler.used");
5472     GV->takeName(Old);
5473     Old->eraseFromParent();
5474   } else {
5475     GV->setName("llvm.embedded.module");
5476   }
5477 
5478   // Skip if only bitcode needs to be embedded.
5479   if (EmbedCmdline) {
5480     // Embed command-line options.
5481     ArrayRef<uint8_t> CmdData(const_cast<uint8_t *>(CmdArgs.data()),
5482                               CmdArgs.size());
5483     llvm::Constant *CmdConstant =
5484         llvm::ConstantDataArray::get(M.getContext(), CmdData);
5485     GV = new llvm::GlobalVariable(M, CmdConstant->getType(), true,
5486                                   llvm::GlobalValue::PrivateLinkage,
5487                                   CmdConstant);
5488     GV->setSection(getSectionNameForCommandline(T));
5489     GV->setAlignment(Align(1));
5490     UsedArray.push_back(
5491         ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
5492     if (llvm::GlobalVariable *Old = M.getGlobalVariable("llvm.cmdline", true)) {
5493       assert(Old->hasZeroLiveUses() &&
5494              "llvm.cmdline can only be used once in llvm.compiler.used");
5495       GV->takeName(Old);
5496       Old->eraseFromParent();
5497     } else {
5498       GV->setName("llvm.cmdline");
5499     }
5500   }
5501 
5502   if (UsedArray.empty())
5503     return;
5504 
5505   // Recreate llvm.compiler.used.
5506   ArrayType *ATy = ArrayType::get(UsedElementType, UsedArray.size());
5507   auto *NewUsed = new GlobalVariable(
5508       M, ATy, false, llvm::GlobalValue::AppendingLinkage,
5509       llvm::ConstantArray::get(ATy, UsedArray), "llvm.compiler.used");
5510   NewUsed->setSection("llvm.metadata");
5511 }
5512