xref: /llvm-project/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp (revision e17a39bc314f97231e440c9e68d9f46a9c07af6d)
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::EndAttrKinds:
897     llvm_unreachable("Can not encode end-attribute kinds marker.");
898   case Attribute::None:
899     llvm_unreachable("Can not encode none-attribute.");
900   case Attribute::EmptyKey:
901   case Attribute::TombstoneKey:
902     llvm_unreachable("Trying to encode EmptyKey/TombstoneKey");
903   }
904 
905   llvm_unreachable("Trying to encode unknown attribute");
906 }
907 
908 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
909   if ((int64_t)V >= 0)
910     Vals.push_back(V << 1);
911   else
912     Vals.push_back((-V << 1) | 1);
913 }
914 
915 static void emitWideAPInt(SmallVectorImpl<uint64_t> &Vals, const APInt &A) {
916   // We have an arbitrary precision integer value to write whose
917   // bit width is > 64. However, in canonical unsigned integer
918   // format it is likely that the high bits are going to be zero.
919   // So, we only write the number of active words.
920   unsigned NumWords = A.getActiveWords();
921   const uint64_t *RawData = A.getRawData();
922   for (unsigned i = 0; i < NumWords; i++)
923     emitSignedInt64(Vals, RawData[i]);
924 }
925 
926 static void emitConstantRange(SmallVectorImpl<uint64_t> &Record,
927                               const ConstantRange &CR, bool EmitBitWidth) {
928   unsigned BitWidth = CR.getBitWidth();
929   if (EmitBitWidth)
930     Record.push_back(BitWidth);
931   if (BitWidth > 64) {
932     Record.push_back(CR.getLower().getActiveWords() |
933                      (uint64_t(CR.getUpper().getActiveWords()) << 32));
934     emitWideAPInt(Record, CR.getLower());
935     emitWideAPInt(Record, CR.getUpper());
936   } else {
937     emitSignedInt64(Record, CR.getLower().getSExtValue());
938     emitSignedInt64(Record, CR.getUpper().getSExtValue());
939   }
940 }
941 
942 void ModuleBitcodeWriter::writeAttributeGroupTable() {
943   const std::vector<ValueEnumerator::IndexAndAttrSet> &AttrGrps =
944       VE.getAttributeGroups();
945   if (AttrGrps.empty()) return;
946 
947   Stream.EnterSubblock(bitc::PARAMATTR_GROUP_BLOCK_ID, 3);
948 
949   SmallVector<uint64_t, 64> Record;
950   for (ValueEnumerator::IndexAndAttrSet Pair : AttrGrps) {
951     unsigned AttrListIndex = Pair.first;
952     AttributeSet AS = Pair.second;
953     Record.push_back(VE.getAttributeGroupID(Pair));
954     Record.push_back(AttrListIndex);
955 
956     for (Attribute Attr : AS) {
957       if (Attr.isEnumAttribute()) {
958         Record.push_back(0);
959         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
960       } else if (Attr.isIntAttribute()) {
961         Record.push_back(1);
962         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
963         Record.push_back(Attr.getValueAsInt());
964       } else if (Attr.isStringAttribute()) {
965         StringRef Kind = Attr.getKindAsString();
966         StringRef Val = Attr.getValueAsString();
967 
968         Record.push_back(Val.empty() ? 3 : 4);
969         Record.append(Kind.begin(), Kind.end());
970         Record.push_back(0);
971         if (!Val.empty()) {
972           Record.append(Val.begin(), Val.end());
973           Record.push_back(0);
974         }
975       } else if (Attr.isTypeAttribute()) {
976         Type *Ty = Attr.getValueAsType();
977         Record.push_back(Ty ? 6 : 5);
978         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
979         if (Ty)
980           Record.push_back(VE.getTypeID(Attr.getValueAsType()));
981       } else if (Attr.isConstantRangeAttribute()) {
982         Record.push_back(7);
983         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
984         emitConstantRange(Record, Attr.getValueAsConstantRange(),
985                           /*EmitBitWidth=*/true);
986       } else {
987         assert(Attr.isConstantRangeListAttribute());
988         Record.push_back(8);
989         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
990         ArrayRef<ConstantRange> Val = Attr.getValueAsConstantRangeList();
991         Record.push_back(Val.size());
992         Record.push_back(Val[0].getBitWidth());
993         for (auto &CR : Val)
994           emitConstantRange(Record, CR, /*EmitBitWidth=*/false);
995       }
996     }
997 
998     Stream.EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
999     Record.clear();
1000   }
1001 
1002   Stream.ExitBlock();
1003 }
1004 
1005 void ModuleBitcodeWriter::writeAttributeTable() {
1006   const std::vector<AttributeList> &Attrs = VE.getAttributeLists();
1007   if (Attrs.empty()) return;
1008 
1009   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
1010 
1011   SmallVector<uint64_t, 64> Record;
1012   for (const AttributeList &AL : Attrs) {
1013     for (unsigned i : AL.indexes()) {
1014       AttributeSet AS = AL.getAttributes(i);
1015       if (AS.hasAttributes())
1016         Record.push_back(VE.getAttributeGroupID({i, AS}));
1017     }
1018 
1019     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
1020     Record.clear();
1021   }
1022 
1023   Stream.ExitBlock();
1024 }
1025 
1026 /// WriteTypeTable - Write out the type table for a module.
1027 void ModuleBitcodeWriter::writeTypeTable() {
1028   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
1029 
1030   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
1031   SmallVector<uint64_t, 64> TypeVals;
1032 
1033   uint64_t NumBits = VE.computeBitsRequiredForTypeIndices();
1034 
1035   // Abbrev for TYPE_CODE_OPAQUE_POINTER.
1036   auto Abbv = std::make_shared<BitCodeAbbrev>();
1037   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_OPAQUE_POINTER));
1038   Abbv->Add(BitCodeAbbrevOp(0)); // Addrspace = 0
1039   unsigned OpaquePtrAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1040 
1041   // Abbrev for TYPE_CODE_FUNCTION.
1042   Abbv = std::make_shared<BitCodeAbbrev>();
1043   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
1044   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
1045   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1046   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
1047   unsigned FunctionAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1048 
1049   // Abbrev for TYPE_CODE_STRUCT_ANON.
1050   Abbv = std::make_shared<BitCodeAbbrev>();
1051   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
1052   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
1053   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1054   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
1055   unsigned StructAnonAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1056 
1057   // Abbrev for TYPE_CODE_STRUCT_NAME.
1058   Abbv = std::make_shared<BitCodeAbbrev>();
1059   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
1060   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1061   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1062   unsigned StructNameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1063 
1064   // Abbrev for TYPE_CODE_STRUCT_NAMED.
1065   Abbv = std::make_shared<BitCodeAbbrev>();
1066   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
1067   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
1068   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1069   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
1070   unsigned StructNamedAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1071 
1072   // Abbrev for TYPE_CODE_ARRAY.
1073   Abbv = std::make_shared<BitCodeAbbrev>();
1074   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
1075   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
1076   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
1077   unsigned ArrayAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1078 
1079   // Emit an entry count so the reader can reserve space.
1080   TypeVals.push_back(TypeList.size());
1081   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
1082   TypeVals.clear();
1083 
1084   // Loop over all of the types, emitting each in turn.
1085   for (Type *T : TypeList) {
1086     int AbbrevToUse = 0;
1087     unsigned Code = 0;
1088 
1089     switch (T->getTypeID()) {
1090     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;      break;
1091     case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;      break;
1092     case Type::BFloatTyID:    Code = bitc::TYPE_CODE_BFLOAT;    break;
1093     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;     break;
1094     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE;    break;
1095     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80;  break;
1096     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128;     break;
1097     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
1098     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;     break;
1099     case Type::MetadataTyID:
1100       Code = bitc::TYPE_CODE_METADATA;
1101       break;
1102     case Type::X86_AMXTyID:   Code = bitc::TYPE_CODE_X86_AMX;   break;
1103     case Type::TokenTyID:     Code = bitc::TYPE_CODE_TOKEN;     break;
1104     case Type::IntegerTyID:
1105       // INTEGER: [width]
1106       Code = bitc::TYPE_CODE_INTEGER;
1107       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
1108       break;
1109     case Type::PointerTyID: {
1110       PointerType *PTy = cast<PointerType>(T);
1111       unsigned AddressSpace = PTy->getAddressSpace();
1112       // OPAQUE_POINTER: [address space]
1113       Code = bitc::TYPE_CODE_OPAQUE_POINTER;
1114       TypeVals.push_back(AddressSpace);
1115       if (AddressSpace == 0)
1116         AbbrevToUse = OpaquePtrAbbrev;
1117       break;
1118     }
1119     case Type::FunctionTyID: {
1120       FunctionType *FT = cast<FunctionType>(T);
1121       // FUNCTION: [isvararg, retty, paramty x N]
1122       Code = bitc::TYPE_CODE_FUNCTION;
1123       TypeVals.push_back(FT->isVarArg());
1124       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
1125       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
1126         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
1127       AbbrevToUse = FunctionAbbrev;
1128       break;
1129     }
1130     case Type::StructTyID: {
1131       StructType *ST = cast<StructType>(T);
1132       // STRUCT: [ispacked, eltty x N]
1133       TypeVals.push_back(ST->isPacked());
1134       // Output all of the element types.
1135       for (Type *ET : ST->elements())
1136         TypeVals.push_back(VE.getTypeID(ET));
1137 
1138       if (ST->isLiteral()) {
1139         Code = bitc::TYPE_CODE_STRUCT_ANON;
1140         AbbrevToUse = StructAnonAbbrev;
1141       } else {
1142         if (ST->isOpaque()) {
1143           Code = bitc::TYPE_CODE_OPAQUE;
1144         } else {
1145           Code = bitc::TYPE_CODE_STRUCT_NAMED;
1146           AbbrevToUse = StructNamedAbbrev;
1147         }
1148 
1149         // Emit the name if it is present.
1150         if (!ST->getName().empty())
1151           writeStringRecord(Stream, bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
1152                             StructNameAbbrev);
1153       }
1154       break;
1155     }
1156     case Type::ArrayTyID: {
1157       ArrayType *AT = cast<ArrayType>(T);
1158       // ARRAY: [numelts, eltty]
1159       Code = bitc::TYPE_CODE_ARRAY;
1160       TypeVals.push_back(AT->getNumElements());
1161       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
1162       AbbrevToUse = ArrayAbbrev;
1163       break;
1164     }
1165     case Type::FixedVectorTyID:
1166     case Type::ScalableVectorTyID: {
1167       VectorType *VT = cast<VectorType>(T);
1168       // VECTOR [numelts, eltty] or
1169       //        [numelts, eltty, scalable]
1170       Code = bitc::TYPE_CODE_VECTOR;
1171       TypeVals.push_back(VT->getElementCount().getKnownMinValue());
1172       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
1173       if (isa<ScalableVectorType>(VT))
1174         TypeVals.push_back(true);
1175       break;
1176     }
1177     case Type::TargetExtTyID: {
1178       TargetExtType *TET = cast<TargetExtType>(T);
1179       Code = bitc::TYPE_CODE_TARGET_TYPE;
1180       writeStringRecord(Stream, bitc::TYPE_CODE_STRUCT_NAME, TET->getName(),
1181                         StructNameAbbrev);
1182       TypeVals.push_back(TET->getNumTypeParameters());
1183       for (Type *InnerTy : TET->type_params())
1184         TypeVals.push_back(VE.getTypeID(InnerTy));
1185       for (unsigned IntParam : TET->int_params())
1186         TypeVals.push_back(IntParam);
1187       break;
1188     }
1189     case Type::TypedPointerTyID:
1190       llvm_unreachable("Typed pointers cannot be added to IR modules");
1191     }
1192 
1193     // Emit the finished record.
1194     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
1195     TypeVals.clear();
1196   }
1197 
1198   Stream.ExitBlock();
1199 }
1200 
1201 static unsigned getEncodedLinkage(const GlobalValue::LinkageTypes Linkage) {
1202   switch (Linkage) {
1203   case GlobalValue::ExternalLinkage:
1204     return 0;
1205   case GlobalValue::WeakAnyLinkage:
1206     return 16;
1207   case GlobalValue::AppendingLinkage:
1208     return 2;
1209   case GlobalValue::InternalLinkage:
1210     return 3;
1211   case GlobalValue::LinkOnceAnyLinkage:
1212     return 18;
1213   case GlobalValue::ExternalWeakLinkage:
1214     return 7;
1215   case GlobalValue::CommonLinkage:
1216     return 8;
1217   case GlobalValue::PrivateLinkage:
1218     return 9;
1219   case GlobalValue::WeakODRLinkage:
1220     return 17;
1221   case GlobalValue::LinkOnceODRLinkage:
1222     return 19;
1223   case GlobalValue::AvailableExternallyLinkage:
1224     return 12;
1225   }
1226   llvm_unreachable("Invalid linkage");
1227 }
1228 
1229 static unsigned getEncodedLinkage(const GlobalValue &GV) {
1230   return getEncodedLinkage(GV.getLinkage());
1231 }
1232 
1233 static uint64_t getEncodedFFlags(FunctionSummary::FFlags Flags) {
1234   uint64_t RawFlags = 0;
1235   RawFlags |= Flags.ReadNone;
1236   RawFlags |= (Flags.ReadOnly << 1);
1237   RawFlags |= (Flags.NoRecurse << 2);
1238   RawFlags |= (Flags.ReturnDoesNotAlias << 3);
1239   RawFlags |= (Flags.NoInline << 4);
1240   RawFlags |= (Flags.AlwaysInline << 5);
1241   RawFlags |= (Flags.NoUnwind << 6);
1242   RawFlags |= (Flags.MayThrow << 7);
1243   RawFlags |= (Flags.HasUnknownCall << 8);
1244   RawFlags |= (Flags.MustBeUnreachable << 9);
1245   return RawFlags;
1246 }
1247 
1248 // Decode the flags for GlobalValue in the summary. See getDecodedGVSummaryFlags
1249 // in BitcodeReader.cpp.
1250 static uint64_t getEncodedGVSummaryFlags(GlobalValueSummary::GVFlags Flags,
1251                                          bool ImportAsDecl = false) {
1252   uint64_t RawFlags = 0;
1253 
1254   RawFlags |= Flags.NotEligibleToImport; // bool
1255   RawFlags |= (Flags.Live << 1);
1256   RawFlags |= (Flags.DSOLocal << 2);
1257   RawFlags |= (Flags.CanAutoHide << 3);
1258 
1259   // Linkage don't need to be remapped at that time for the summary. Any future
1260   // change to the getEncodedLinkage() function will need to be taken into
1261   // account here as well.
1262   RawFlags = (RawFlags << 4) | Flags.Linkage; // 4 bits
1263 
1264   RawFlags |= (Flags.Visibility << 8); // 2 bits
1265 
1266   unsigned ImportType = Flags.ImportType | ImportAsDecl;
1267   RawFlags |= (ImportType << 10); // 1 bit
1268 
1269   return RawFlags;
1270 }
1271 
1272 static uint64_t getEncodedGVarFlags(GlobalVarSummary::GVarFlags Flags) {
1273   uint64_t RawFlags = Flags.MaybeReadOnly | (Flags.MaybeWriteOnly << 1) |
1274                       (Flags.Constant << 2) | Flags.VCallVisibility << 3;
1275   return RawFlags;
1276 }
1277 
1278 static uint64_t getEncodedHotnessCallEdgeInfo(const CalleeInfo &CI) {
1279   uint64_t RawFlags = 0;
1280 
1281   RawFlags |= CI.Hotness;            // 3 bits
1282   RawFlags |= (CI.HasTailCall << 3); // 1 bit
1283 
1284   return RawFlags;
1285 }
1286 
1287 static uint64_t getEncodedRelBFCallEdgeInfo(const CalleeInfo &CI) {
1288   uint64_t RawFlags = 0;
1289 
1290   RawFlags |= CI.RelBlockFreq; // CalleeInfo::RelBlockFreqBits bits
1291   RawFlags |= (CI.HasTailCall << CalleeInfo::RelBlockFreqBits); // 1 bit
1292 
1293   return RawFlags;
1294 }
1295 
1296 static unsigned getEncodedVisibility(const GlobalValue &GV) {
1297   switch (GV.getVisibility()) {
1298   case GlobalValue::DefaultVisibility:   return 0;
1299   case GlobalValue::HiddenVisibility:    return 1;
1300   case GlobalValue::ProtectedVisibility: return 2;
1301   }
1302   llvm_unreachable("Invalid visibility");
1303 }
1304 
1305 static unsigned getEncodedDLLStorageClass(const GlobalValue &GV) {
1306   switch (GV.getDLLStorageClass()) {
1307   case GlobalValue::DefaultStorageClass:   return 0;
1308   case GlobalValue::DLLImportStorageClass: return 1;
1309   case GlobalValue::DLLExportStorageClass: return 2;
1310   }
1311   llvm_unreachable("Invalid DLL storage class");
1312 }
1313 
1314 static unsigned getEncodedThreadLocalMode(const GlobalValue &GV) {
1315   switch (GV.getThreadLocalMode()) {
1316     case GlobalVariable::NotThreadLocal:         return 0;
1317     case GlobalVariable::GeneralDynamicTLSModel: return 1;
1318     case GlobalVariable::LocalDynamicTLSModel:   return 2;
1319     case GlobalVariable::InitialExecTLSModel:    return 3;
1320     case GlobalVariable::LocalExecTLSModel:      return 4;
1321   }
1322   llvm_unreachable("Invalid TLS model");
1323 }
1324 
1325 static unsigned getEncodedComdatSelectionKind(const Comdat &C) {
1326   switch (C.getSelectionKind()) {
1327   case Comdat::Any:
1328     return bitc::COMDAT_SELECTION_KIND_ANY;
1329   case Comdat::ExactMatch:
1330     return bitc::COMDAT_SELECTION_KIND_EXACT_MATCH;
1331   case Comdat::Largest:
1332     return bitc::COMDAT_SELECTION_KIND_LARGEST;
1333   case Comdat::NoDeduplicate:
1334     return bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES;
1335   case Comdat::SameSize:
1336     return bitc::COMDAT_SELECTION_KIND_SAME_SIZE;
1337   }
1338   llvm_unreachable("Invalid selection kind");
1339 }
1340 
1341 static unsigned getEncodedUnnamedAddr(const GlobalValue &GV) {
1342   switch (GV.getUnnamedAddr()) {
1343   case GlobalValue::UnnamedAddr::None:   return 0;
1344   case GlobalValue::UnnamedAddr::Local:  return 2;
1345   case GlobalValue::UnnamedAddr::Global: return 1;
1346   }
1347   llvm_unreachable("Invalid unnamed_addr");
1348 }
1349 
1350 size_t ModuleBitcodeWriter::addToStrtab(StringRef Str) {
1351   if (GenerateHash)
1352     Hasher.update(Str);
1353   return StrtabBuilder.add(Str);
1354 }
1355 
1356 void ModuleBitcodeWriter::writeComdats() {
1357   SmallVector<unsigned, 64> Vals;
1358   for (const Comdat *C : VE.getComdats()) {
1359     // COMDAT: [strtab offset, strtab size, selection_kind]
1360     Vals.push_back(addToStrtab(C->getName()));
1361     Vals.push_back(C->getName().size());
1362     Vals.push_back(getEncodedComdatSelectionKind(*C));
1363     Stream.EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
1364     Vals.clear();
1365   }
1366 }
1367 
1368 /// Write a record that will eventually hold the word offset of the
1369 /// module-level VST. For now the offset is 0, which will be backpatched
1370 /// after the real VST is written. Saves the bit offset to backpatch.
1371 void ModuleBitcodeWriter::writeValueSymbolTableForwardDecl() {
1372   // Write a placeholder value in for the offset of the real VST,
1373   // which is written after the function blocks so that it can include
1374   // the offset of each function. The placeholder offset will be
1375   // updated when the real VST is written.
1376   auto Abbv = std::make_shared<BitCodeAbbrev>();
1377   Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_VSTOFFSET));
1378   // Blocks are 32-bit aligned, so we can use a 32-bit word offset to
1379   // hold the real VST offset. Must use fixed instead of VBR as we don't
1380   // know how many VBR chunks to reserve ahead of time.
1381   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
1382   unsigned VSTOffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1383 
1384   // Emit the placeholder
1385   uint64_t Vals[] = {bitc::MODULE_CODE_VSTOFFSET, 0};
1386   Stream.EmitRecordWithAbbrev(VSTOffsetAbbrev, Vals);
1387 
1388   // Compute and save the bit offset to the placeholder, which will be
1389   // patched when the real VST is written. We can simply subtract the 32-bit
1390   // fixed size from the current bit number to get the location to backpatch.
1391   VSTOffsetPlaceholder = Stream.GetCurrentBitNo() - 32;
1392 }
1393 
1394 enum StringEncoding { SE_Char6, SE_Fixed7, SE_Fixed8 };
1395 
1396 /// Determine the encoding to use for the given string name and length.
1397 static StringEncoding getStringEncoding(StringRef Str) {
1398   bool isChar6 = true;
1399   for (char C : Str) {
1400     if (isChar6)
1401       isChar6 = BitCodeAbbrevOp::isChar6(C);
1402     if ((unsigned char)C & 128)
1403       // don't bother scanning the rest.
1404       return SE_Fixed8;
1405   }
1406   if (isChar6)
1407     return SE_Char6;
1408   return SE_Fixed7;
1409 }
1410 
1411 static_assert(sizeof(GlobalValue::SanitizerMetadata) <= sizeof(unsigned),
1412               "Sanitizer Metadata is too large for naive serialization.");
1413 static unsigned
1414 serializeSanitizerMetadata(const GlobalValue::SanitizerMetadata &Meta) {
1415   return Meta.NoAddress | (Meta.NoHWAddress << 1) |
1416          (Meta.Memtag << 2) | (Meta.IsDynInit << 3);
1417 }
1418 
1419 /// Emit top-level description of module, including target triple, inline asm,
1420 /// descriptors for global variables, and function prototype info.
1421 /// Returns the bit offset to backpatch with the location of the real VST.
1422 void ModuleBitcodeWriter::writeModuleInfo() {
1423   // Emit various pieces of data attached to a module.
1424   if (!M.getTargetTriple().empty())
1425     writeStringRecord(Stream, bitc::MODULE_CODE_TRIPLE, M.getTargetTriple(),
1426                       0 /*TODO*/);
1427   const std::string &DL = M.getDataLayoutStr();
1428   if (!DL.empty())
1429     writeStringRecord(Stream, bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/);
1430   if (!M.getModuleInlineAsm().empty())
1431     writeStringRecord(Stream, bitc::MODULE_CODE_ASM, M.getModuleInlineAsm(),
1432                       0 /*TODO*/);
1433 
1434   // Emit information about sections and GC, computing how many there are. Also
1435   // compute the maximum alignment value.
1436   std::map<std::string, unsigned> SectionMap;
1437   std::map<std::string, unsigned> GCMap;
1438   MaybeAlign MaxAlignment;
1439   unsigned MaxGlobalType = 0;
1440   const auto UpdateMaxAlignment = [&MaxAlignment](const MaybeAlign A) {
1441     if (A)
1442       MaxAlignment = !MaxAlignment ? *A : std::max(*MaxAlignment, *A);
1443   };
1444   for (const GlobalVariable &GV : M.globals()) {
1445     UpdateMaxAlignment(GV.getAlign());
1446     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getValueType()));
1447     if (GV.hasSection()) {
1448       // Give section names unique ID's.
1449       unsigned &Entry = SectionMap[std::string(GV.getSection())];
1450       if (!Entry) {
1451         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
1452                           0 /*TODO*/);
1453         Entry = SectionMap.size();
1454       }
1455     }
1456   }
1457   for (const Function &F : M) {
1458     UpdateMaxAlignment(F.getAlign());
1459     if (F.hasSection()) {
1460       // Give section names unique ID's.
1461       unsigned &Entry = SectionMap[std::string(F.getSection())];
1462       if (!Entry) {
1463         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
1464                           0 /*TODO*/);
1465         Entry = SectionMap.size();
1466       }
1467     }
1468     if (F.hasGC()) {
1469       // Same for GC names.
1470       unsigned &Entry = GCMap[F.getGC()];
1471       if (!Entry) {
1472         writeStringRecord(Stream, bitc::MODULE_CODE_GCNAME, F.getGC(),
1473                           0 /*TODO*/);
1474         Entry = GCMap.size();
1475       }
1476     }
1477   }
1478 
1479   // Emit abbrev for globals, now that we know # sections and max alignment.
1480   unsigned SimpleGVarAbbrev = 0;
1481   if (!M.global_empty()) {
1482     // Add an abbrev for common globals with no visibility or thread localness.
1483     auto Abbv = std::make_shared<BitCodeAbbrev>();
1484     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
1485     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1486     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1487     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1488                               Log2_32_Ceil(MaxGlobalType+1)));
1489     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddrSpace << 2
1490                                                            //| explicitType << 1
1491                                                            //| constant
1492     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Initializer.
1493     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // Linkage.
1494     if (!MaxAlignment)                                     // Alignment.
1495       Abbv->Add(BitCodeAbbrevOp(0));
1496     else {
1497       unsigned MaxEncAlignment = getEncodedAlign(MaxAlignment);
1498       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1499                                Log2_32_Ceil(MaxEncAlignment+1)));
1500     }
1501     if (SectionMap.empty())                                    // Section.
1502       Abbv->Add(BitCodeAbbrevOp(0));
1503     else
1504       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1505                                Log2_32_Ceil(SectionMap.size()+1)));
1506     // Don't bother emitting vis + thread local.
1507     SimpleGVarAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1508   }
1509 
1510   SmallVector<unsigned, 64> Vals;
1511   // Emit the module's source file name.
1512   {
1513     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
1514     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
1515     if (Bits == SE_Char6)
1516       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
1517     else if (Bits == SE_Fixed7)
1518       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
1519 
1520     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
1521     auto Abbv = std::make_shared<BitCodeAbbrev>();
1522     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
1523     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1524     Abbv->Add(AbbrevOpToUse);
1525     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1526 
1527     for (const auto P : M.getSourceFileName())
1528       Vals.push_back((unsigned char)P);
1529 
1530     // Emit the finished record.
1531     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
1532     Vals.clear();
1533   }
1534 
1535   // Emit the global variable information.
1536   for (const GlobalVariable &GV : M.globals()) {
1537     unsigned AbbrevToUse = 0;
1538 
1539     // GLOBALVAR: [strtab offset, strtab size, type, isconst, initid,
1540     //             linkage, alignment, section, visibility, threadlocal,
1541     //             unnamed_addr, externally_initialized, dllstorageclass,
1542     //             comdat, attributes, DSO_Local, GlobalSanitizer, code_model]
1543     Vals.push_back(addToStrtab(GV.getName()));
1544     Vals.push_back(GV.getName().size());
1545     Vals.push_back(VE.getTypeID(GV.getValueType()));
1546     Vals.push_back(GV.getType()->getAddressSpace() << 2 | 2 | GV.isConstant());
1547     Vals.push_back(GV.isDeclaration() ? 0 :
1548                    (VE.getValueID(GV.getInitializer()) + 1));
1549     Vals.push_back(getEncodedLinkage(GV));
1550     Vals.push_back(getEncodedAlign(GV.getAlign()));
1551     Vals.push_back(GV.hasSection() ? SectionMap[std::string(GV.getSection())]
1552                                    : 0);
1553     if (GV.isThreadLocal() ||
1554         GV.getVisibility() != GlobalValue::DefaultVisibility ||
1555         GV.getUnnamedAddr() != GlobalValue::UnnamedAddr::None ||
1556         GV.isExternallyInitialized() ||
1557         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
1558         GV.hasComdat() || GV.hasAttributes() || GV.isDSOLocal() ||
1559         GV.hasPartition() || GV.hasSanitizerMetadata() || GV.getCodeModel()) {
1560       Vals.push_back(getEncodedVisibility(GV));
1561       Vals.push_back(getEncodedThreadLocalMode(GV));
1562       Vals.push_back(getEncodedUnnamedAddr(GV));
1563       Vals.push_back(GV.isExternallyInitialized());
1564       Vals.push_back(getEncodedDLLStorageClass(GV));
1565       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
1566 
1567       auto AL = GV.getAttributesAsList(AttributeList::FunctionIndex);
1568       Vals.push_back(VE.getAttributeListID(AL));
1569 
1570       Vals.push_back(GV.isDSOLocal());
1571       Vals.push_back(addToStrtab(GV.getPartition()));
1572       Vals.push_back(GV.getPartition().size());
1573 
1574       Vals.push_back((GV.hasSanitizerMetadata() ? serializeSanitizerMetadata(
1575                                                       GV.getSanitizerMetadata())
1576                                                 : 0));
1577       Vals.push_back(GV.getCodeModelRaw());
1578     } else {
1579       AbbrevToUse = SimpleGVarAbbrev;
1580     }
1581 
1582     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
1583     Vals.clear();
1584   }
1585 
1586   // Emit the function proto information.
1587   for (const Function &F : M) {
1588     // FUNCTION:  [strtab offset, strtab size, type, callingconv, isproto,
1589     //             linkage, paramattrs, alignment, section, visibility, gc,
1590     //             unnamed_addr, prologuedata, dllstorageclass, comdat,
1591     //             prefixdata, personalityfn, DSO_Local, addrspace]
1592     Vals.push_back(addToStrtab(F.getName()));
1593     Vals.push_back(F.getName().size());
1594     Vals.push_back(VE.getTypeID(F.getFunctionType()));
1595     Vals.push_back(F.getCallingConv());
1596     Vals.push_back(F.isDeclaration());
1597     Vals.push_back(getEncodedLinkage(F));
1598     Vals.push_back(VE.getAttributeListID(F.getAttributes()));
1599     Vals.push_back(getEncodedAlign(F.getAlign()));
1600     Vals.push_back(F.hasSection() ? SectionMap[std::string(F.getSection())]
1601                                   : 0);
1602     Vals.push_back(getEncodedVisibility(F));
1603     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
1604     Vals.push_back(getEncodedUnnamedAddr(F));
1605     Vals.push_back(F.hasPrologueData() ? (VE.getValueID(F.getPrologueData()) + 1)
1606                                        : 0);
1607     Vals.push_back(getEncodedDLLStorageClass(F));
1608     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
1609     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
1610                                      : 0);
1611     Vals.push_back(
1612         F.hasPersonalityFn() ? (VE.getValueID(F.getPersonalityFn()) + 1) : 0);
1613 
1614     Vals.push_back(F.isDSOLocal());
1615     Vals.push_back(F.getAddressSpace());
1616     Vals.push_back(addToStrtab(F.getPartition()));
1617     Vals.push_back(F.getPartition().size());
1618 
1619     unsigned AbbrevToUse = 0;
1620     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
1621     Vals.clear();
1622   }
1623 
1624   // Emit the alias information.
1625   for (const GlobalAlias &A : M.aliases()) {
1626     // ALIAS: [strtab offset, strtab size, alias type, aliasee val#, linkage,
1627     //         visibility, dllstorageclass, threadlocal, unnamed_addr,
1628     //         DSO_Local]
1629     Vals.push_back(addToStrtab(A.getName()));
1630     Vals.push_back(A.getName().size());
1631     Vals.push_back(VE.getTypeID(A.getValueType()));
1632     Vals.push_back(A.getType()->getAddressSpace());
1633     Vals.push_back(VE.getValueID(A.getAliasee()));
1634     Vals.push_back(getEncodedLinkage(A));
1635     Vals.push_back(getEncodedVisibility(A));
1636     Vals.push_back(getEncodedDLLStorageClass(A));
1637     Vals.push_back(getEncodedThreadLocalMode(A));
1638     Vals.push_back(getEncodedUnnamedAddr(A));
1639     Vals.push_back(A.isDSOLocal());
1640     Vals.push_back(addToStrtab(A.getPartition()));
1641     Vals.push_back(A.getPartition().size());
1642 
1643     unsigned AbbrevToUse = 0;
1644     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
1645     Vals.clear();
1646   }
1647 
1648   // Emit the ifunc information.
1649   for (const GlobalIFunc &I : M.ifuncs()) {
1650     // IFUNC: [strtab offset, strtab size, ifunc type, address space, resolver
1651     //         val#, linkage, visibility, DSO_Local]
1652     Vals.push_back(addToStrtab(I.getName()));
1653     Vals.push_back(I.getName().size());
1654     Vals.push_back(VE.getTypeID(I.getValueType()));
1655     Vals.push_back(I.getType()->getAddressSpace());
1656     Vals.push_back(VE.getValueID(I.getResolver()));
1657     Vals.push_back(getEncodedLinkage(I));
1658     Vals.push_back(getEncodedVisibility(I));
1659     Vals.push_back(I.isDSOLocal());
1660     Vals.push_back(addToStrtab(I.getPartition()));
1661     Vals.push_back(I.getPartition().size());
1662     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
1663     Vals.clear();
1664   }
1665 
1666   writeValueSymbolTableForwardDecl();
1667 }
1668 
1669 static uint64_t getOptimizationFlags(const Value *V) {
1670   uint64_t Flags = 0;
1671 
1672   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
1673     if (OBO->hasNoSignedWrap())
1674       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
1675     if (OBO->hasNoUnsignedWrap())
1676       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
1677   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
1678     if (PEO->isExact())
1679       Flags |= 1 << bitc::PEO_EXACT;
1680   } else if (const auto *PDI = dyn_cast<PossiblyDisjointInst>(V)) {
1681     if (PDI->isDisjoint())
1682       Flags |= 1 << bitc::PDI_DISJOINT;
1683   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
1684     if (FPMO->hasAllowReassoc())
1685       Flags |= bitc::AllowReassoc;
1686     if (FPMO->hasNoNaNs())
1687       Flags |= bitc::NoNaNs;
1688     if (FPMO->hasNoInfs())
1689       Flags |= bitc::NoInfs;
1690     if (FPMO->hasNoSignedZeros())
1691       Flags |= bitc::NoSignedZeros;
1692     if (FPMO->hasAllowReciprocal())
1693       Flags |= bitc::AllowReciprocal;
1694     if (FPMO->hasAllowContract())
1695       Flags |= bitc::AllowContract;
1696     if (FPMO->hasApproxFunc())
1697       Flags |= bitc::ApproxFunc;
1698   } else if (const auto *NNI = dyn_cast<PossiblyNonNegInst>(V)) {
1699     if (NNI->hasNonNeg())
1700       Flags |= 1 << bitc::PNNI_NON_NEG;
1701   } else if (const auto *TI = dyn_cast<TruncInst>(V)) {
1702     if (TI->hasNoSignedWrap())
1703       Flags |= 1 << bitc::TIO_NO_SIGNED_WRAP;
1704     if (TI->hasNoUnsignedWrap())
1705       Flags |= 1 << bitc::TIO_NO_UNSIGNED_WRAP;
1706   } else if (const auto *GEP = dyn_cast<GEPOperator>(V)) {
1707     if (GEP->isInBounds())
1708       Flags |= 1 << bitc::GEP_INBOUNDS;
1709     if (GEP->hasNoUnsignedSignedWrap())
1710       Flags |= 1 << bitc::GEP_NUSW;
1711     if (GEP->hasNoUnsignedWrap())
1712       Flags |= 1 << bitc::GEP_NUW;
1713   }
1714 
1715   return Flags;
1716 }
1717 
1718 void ModuleBitcodeWriter::writeValueAsMetadata(
1719     const ValueAsMetadata *MD, SmallVectorImpl<uint64_t> &Record) {
1720   // Mimic an MDNode with a value as one operand.
1721   Value *V = MD->getValue();
1722   Record.push_back(VE.getTypeID(V->getType()));
1723   Record.push_back(VE.getValueID(V));
1724   Stream.EmitRecord(bitc::METADATA_VALUE, Record, 0);
1725   Record.clear();
1726 }
1727 
1728 void ModuleBitcodeWriter::writeMDTuple(const MDTuple *N,
1729                                        SmallVectorImpl<uint64_t> &Record,
1730                                        unsigned Abbrev) {
1731   for (const MDOperand &MDO : N->operands()) {
1732     Metadata *MD = MDO;
1733     assert(!(MD && isa<LocalAsMetadata>(MD)) &&
1734            "Unexpected function-local metadata");
1735     Record.push_back(VE.getMetadataOrNullID(MD));
1736   }
1737   Stream.EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
1738                                     : bitc::METADATA_NODE,
1739                     Record, Abbrev);
1740   Record.clear();
1741 }
1742 
1743 unsigned ModuleBitcodeWriter::createDILocationAbbrev() {
1744   // Assume the column is usually under 128, and always output the inlined-at
1745   // location (it's never more expensive than building an array size 1).
1746   auto Abbv = std::make_shared<BitCodeAbbrev>();
1747   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
1748   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1749   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1750   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1751   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1752   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1753   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1754   return Stream.EmitAbbrev(std::move(Abbv));
1755 }
1756 
1757 void ModuleBitcodeWriter::writeDILocation(const DILocation *N,
1758                                           SmallVectorImpl<uint64_t> &Record,
1759                                           unsigned &Abbrev) {
1760   if (!Abbrev)
1761     Abbrev = createDILocationAbbrev();
1762 
1763   Record.push_back(N->isDistinct());
1764   Record.push_back(N->getLine());
1765   Record.push_back(N->getColumn());
1766   Record.push_back(VE.getMetadataID(N->getScope()));
1767   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
1768   Record.push_back(N->isImplicitCode());
1769 
1770   Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
1771   Record.clear();
1772 }
1773 
1774 unsigned ModuleBitcodeWriter::createGenericDINodeAbbrev() {
1775   // Assume the column is usually under 128, and always output the inlined-at
1776   // location (it's never more expensive than building an array size 1).
1777   auto Abbv = std::make_shared<BitCodeAbbrev>();
1778   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
1779   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1780   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1781   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1782   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1783   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1784   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1785   return Stream.EmitAbbrev(std::move(Abbv));
1786 }
1787 
1788 void ModuleBitcodeWriter::writeGenericDINode(const GenericDINode *N,
1789                                              SmallVectorImpl<uint64_t> &Record,
1790                                              unsigned &Abbrev) {
1791   if (!Abbrev)
1792     Abbrev = createGenericDINodeAbbrev();
1793 
1794   Record.push_back(N->isDistinct());
1795   Record.push_back(N->getTag());
1796   Record.push_back(0); // Per-tag version field; unused for now.
1797 
1798   for (auto &I : N->operands())
1799     Record.push_back(VE.getMetadataOrNullID(I));
1800 
1801   Stream.EmitRecord(bitc::METADATA_GENERIC_DEBUG, Record, Abbrev);
1802   Record.clear();
1803 }
1804 
1805 void ModuleBitcodeWriter::writeDISubrange(const DISubrange *N,
1806                                           SmallVectorImpl<uint64_t> &Record,
1807                                           unsigned Abbrev) {
1808   const uint64_t Version = 2 << 1;
1809   Record.push_back((uint64_t)N->isDistinct() | Version);
1810   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1811   Record.push_back(VE.getMetadataOrNullID(N->getRawLowerBound()));
1812   Record.push_back(VE.getMetadataOrNullID(N->getRawUpperBound()));
1813   Record.push_back(VE.getMetadataOrNullID(N->getRawStride()));
1814 
1815   Stream.EmitRecord(bitc::METADATA_SUBRANGE, Record, Abbrev);
1816   Record.clear();
1817 }
1818 
1819 void ModuleBitcodeWriter::writeDIGenericSubrange(
1820     const DIGenericSubrange *N, SmallVectorImpl<uint64_t> &Record,
1821     unsigned Abbrev) {
1822   Record.push_back((uint64_t)N->isDistinct());
1823   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1824   Record.push_back(VE.getMetadataOrNullID(N->getRawLowerBound()));
1825   Record.push_back(VE.getMetadataOrNullID(N->getRawUpperBound()));
1826   Record.push_back(VE.getMetadataOrNullID(N->getRawStride()));
1827 
1828   Stream.EmitRecord(bitc::METADATA_GENERIC_SUBRANGE, Record, Abbrev);
1829   Record.clear();
1830 }
1831 
1832 void ModuleBitcodeWriter::writeDIEnumerator(const DIEnumerator *N,
1833                                             SmallVectorImpl<uint64_t> &Record,
1834                                             unsigned Abbrev) {
1835   const uint64_t IsBigInt = 1 << 2;
1836   Record.push_back(IsBigInt | (N->isUnsigned() << 1) | N->isDistinct());
1837   Record.push_back(N->getValue().getBitWidth());
1838   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1839   emitWideAPInt(Record, N->getValue());
1840 
1841   Stream.EmitRecord(bitc::METADATA_ENUMERATOR, Record, Abbrev);
1842   Record.clear();
1843 }
1844 
1845 void ModuleBitcodeWriter::writeDIBasicType(const DIBasicType *N,
1846                                            SmallVectorImpl<uint64_t> &Record,
1847                                            unsigned Abbrev) {
1848   Record.push_back(N->isDistinct());
1849   Record.push_back(N->getTag());
1850   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1851   Record.push_back(N->getSizeInBits());
1852   Record.push_back(N->getAlignInBits());
1853   Record.push_back(N->getEncoding());
1854   Record.push_back(N->getFlags());
1855 
1856   Stream.EmitRecord(bitc::METADATA_BASIC_TYPE, Record, Abbrev);
1857   Record.clear();
1858 }
1859 
1860 void ModuleBitcodeWriter::writeDIStringType(const DIStringType *N,
1861                                             SmallVectorImpl<uint64_t> &Record,
1862                                             unsigned Abbrev) {
1863   Record.push_back(N->isDistinct());
1864   Record.push_back(N->getTag());
1865   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1866   Record.push_back(VE.getMetadataOrNullID(N->getStringLength()));
1867   Record.push_back(VE.getMetadataOrNullID(N->getStringLengthExp()));
1868   Record.push_back(VE.getMetadataOrNullID(N->getStringLocationExp()));
1869   Record.push_back(N->getSizeInBits());
1870   Record.push_back(N->getAlignInBits());
1871   Record.push_back(N->getEncoding());
1872 
1873   Stream.EmitRecord(bitc::METADATA_STRING_TYPE, Record, Abbrev);
1874   Record.clear();
1875 }
1876 
1877 void ModuleBitcodeWriter::writeDIDerivedType(const DIDerivedType *N,
1878                                              SmallVectorImpl<uint64_t> &Record,
1879                                              unsigned Abbrev) {
1880   Record.push_back(N->isDistinct());
1881   Record.push_back(N->getTag());
1882   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1883   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1884   Record.push_back(N->getLine());
1885   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1886   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1887   Record.push_back(N->getSizeInBits());
1888   Record.push_back(N->getAlignInBits());
1889   Record.push_back(N->getOffsetInBits());
1890   Record.push_back(N->getFlags());
1891   Record.push_back(VE.getMetadataOrNullID(N->getExtraData()));
1892 
1893   // DWARF address space is encoded as N->getDWARFAddressSpace() + 1. 0 means
1894   // that there is no DWARF address space associated with DIDerivedType.
1895   if (const auto &DWARFAddressSpace = N->getDWARFAddressSpace())
1896     Record.push_back(*DWARFAddressSpace + 1);
1897   else
1898     Record.push_back(0);
1899 
1900   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1901 
1902   if (auto PtrAuthData = N->getPtrAuthData())
1903     Record.push_back(PtrAuthData->RawData);
1904   else
1905     Record.push_back(0);
1906 
1907   Stream.EmitRecord(bitc::METADATA_DERIVED_TYPE, Record, Abbrev);
1908   Record.clear();
1909 }
1910 
1911 void ModuleBitcodeWriter::writeDICompositeType(
1912     const DICompositeType *N, SmallVectorImpl<uint64_t> &Record,
1913     unsigned Abbrev) {
1914   const unsigned IsNotUsedInOldTypeRef = 0x2;
1915   Record.push_back(IsNotUsedInOldTypeRef | (unsigned)N->isDistinct());
1916   Record.push_back(N->getTag());
1917   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1918   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1919   Record.push_back(N->getLine());
1920   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1921   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1922   Record.push_back(N->getSizeInBits());
1923   Record.push_back(N->getAlignInBits());
1924   Record.push_back(N->getOffsetInBits());
1925   Record.push_back(N->getFlags());
1926   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1927   Record.push_back(N->getRuntimeLang());
1928   Record.push_back(VE.getMetadataOrNullID(N->getVTableHolder()));
1929   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1930   Record.push_back(VE.getMetadataOrNullID(N->getRawIdentifier()));
1931   Record.push_back(VE.getMetadataOrNullID(N->getDiscriminator()));
1932   Record.push_back(VE.getMetadataOrNullID(N->getRawDataLocation()));
1933   Record.push_back(VE.getMetadataOrNullID(N->getRawAssociated()));
1934   Record.push_back(VE.getMetadataOrNullID(N->getRawAllocated()));
1935   Record.push_back(VE.getMetadataOrNullID(N->getRawRank()));
1936   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1937 
1938   Stream.EmitRecord(bitc::METADATA_COMPOSITE_TYPE, Record, Abbrev);
1939   Record.clear();
1940 }
1941 
1942 void ModuleBitcodeWriter::writeDISubroutineType(
1943     const DISubroutineType *N, SmallVectorImpl<uint64_t> &Record,
1944     unsigned Abbrev) {
1945   const unsigned HasNoOldTypeRefs = 0x2;
1946   Record.push_back(HasNoOldTypeRefs | (unsigned)N->isDistinct());
1947   Record.push_back(N->getFlags());
1948   Record.push_back(VE.getMetadataOrNullID(N->getTypeArray().get()));
1949   Record.push_back(N->getCC());
1950 
1951   Stream.EmitRecord(bitc::METADATA_SUBROUTINE_TYPE, Record, Abbrev);
1952   Record.clear();
1953 }
1954 
1955 void ModuleBitcodeWriter::writeDIFile(const DIFile *N,
1956                                       SmallVectorImpl<uint64_t> &Record,
1957                                       unsigned Abbrev) {
1958   Record.push_back(N->isDistinct());
1959   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
1960   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
1961   if (N->getRawChecksum()) {
1962     Record.push_back(N->getRawChecksum()->Kind);
1963     Record.push_back(VE.getMetadataOrNullID(N->getRawChecksum()->Value));
1964   } else {
1965     // Maintain backwards compatibility with the old internal representation of
1966     // CSK_None in ChecksumKind by writing nulls here when Checksum is None.
1967     Record.push_back(0);
1968     Record.push_back(VE.getMetadataOrNullID(nullptr));
1969   }
1970   auto Source = N->getRawSource();
1971   if (Source)
1972     Record.push_back(VE.getMetadataOrNullID(Source));
1973 
1974   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
1975   Record.clear();
1976 }
1977 
1978 void ModuleBitcodeWriter::writeDICompileUnit(const DICompileUnit *N,
1979                                              SmallVectorImpl<uint64_t> &Record,
1980                                              unsigned Abbrev) {
1981   assert(N->isDistinct() && "Expected distinct compile units");
1982   Record.push_back(/* IsDistinct */ true);
1983   Record.push_back(N->getSourceLanguage());
1984   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1985   Record.push_back(VE.getMetadataOrNullID(N->getRawProducer()));
1986   Record.push_back(N->isOptimized());
1987   Record.push_back(VE.getMetadataOrNullID(N->getRawFlags()));
1988   Record.push_back(N->getRuntimeVersion());
1989   Record.push_back(VE.getMetadataOrNullID(N->getRawSplitDebugFilename()));
1990   Record.push_back(N->getEmissionKind());
1991   Record.push_back(VE.getMetadataOrNullID(N->getEnumTypes().get()));
1992   Record.push_back(VE.getMetadataOrNullID(N->getRetainedTypes().get()));
1993   Record.push_back(/* subprograms */ 0);
1994   Record.push_back(VE.getMetadataOrNullID(N->getGlobalVariables().get()));
1995   Record.push_back(VE.getMetadataOrNullID(N->getImportedEntities().get()));
1996   Record.push_back(N->getDWOId());
1997   Record.push_back(VE.getMetadataOrNullID(N->getMacros().get()));
1998   Record.push_back(N->getSplitDebugInlining());
1999   Record.push_back(N->getDebugInfoForProfiling());
2000   Record.push_back((unsigned)N->getNameTableKind());
2001   Record.push_back(N->getRangesBaseAddress());
2002   Record.push_back(VE.getMetadataOrNullID(N->getRawSysRoot()));
2003   Record.push_back(VE.getMetadataOrNullID(N->getRawSDK()));
2004 
2005   Stream.EmitRecord(bitc::METADATA_COMPILE_UNIT, Record, Abbrev);
2006   Record.clear();
2007 }
2008 
2009 void ModuleBitcodeWriter::writeDISubprogram(const DISubprogram *N,
2010                                             SmallVectorImpl<uint64_t> &Record,
2011                                             unsigned Abbrev) {
2012   const uint64_t HasUnitFlag = 1 << 1;
2013   const uint64_t HasSPFlagsFlag = 1 << 2;
2014   Record.push_back(uint64_t(N->isDistinct()) | HasUnitFlag | HasSPFlagsFlag);
2015   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2016   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2017   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
2018   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2019   Record.push_back(N->getLine());
2020   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2021   Record.push_back(N->getScopeLine());
2022   Record.push_back(VE.getMetadataOrNullID(N->getContainingType()));
2023   Record.push_back(N->getSPFlags());
2024   Record.push_back(N->getVirtualIndex());
2025   Record.push_back(N->getFlags());
2026   Record.push_back(VE.getMetadataOrNullID(N->getRawUnit()));
2027   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
2028   Record.push_back(VE.getMetadataOrNullID(N->getDeclaration()));
2029   Record.push_back(VE.getMetadataOrNullID(N->getRetainedNodes().get()));
2030   Record.push_back(N->getThisAdjustment());
2031   Record.push_back(VE.getMetadataOrNullID(N->getThrownTypes().get()));
2032   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
2033   Record.push_back(VE.getMetadataOrNullID(N->getRawTargetFuncName()));
2034 
2035   Stream.EmitRecord(bitc::METADATA_SUBPROGRAM, Record, Abbrev);
2036   Record.clear();
2037 }
2038 
2039 void ModuleBitcodeWriter::writeDILexicalBlock(const DILexicalBlock *N,
2040                                               SmallVectorImpl<uint64_t> &Record,
2041                                               unsigned Abbrev) {
2042   Record.push_back(N->isDistinct());
2043   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2044   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2045   Record.push_back(N->getLine());
2046   Record.push_back(N->getColumn());
2047 
2048   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK, Record, Abbrev);
2049   Record.clear();
2050 }
2051 
2052 void ModuleBitcodeWriter::writeDILexicalBlockFile(
2053     const DILexicalBlockFile *N, SmallVectorImpl<uint64_t> &Record,
2054     unsigned Abbrev) {
2055   Record.push_back(N->isDistinct());
2056   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2057   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2058   Record.push_back(N->getDiscriminator());
2059 
2060   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK_FILE, Record, Abbrev);
2061   Record.clear();
2062 }
2063 
2064 void ModuleBitcodeWriter::writeDICommonBlock(const DICommonBlock *N,
2065                                              SmallVectorImpl<uint64_t> &Record,
2066                                              unsigned Abbrev) {
2067   Record.push_back(N->isDistinct());
2068   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2069   Record.push_back(VE.getMetadataOrNullID(N->getDecl()));
2070   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2071   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2072   Record.push_back(N->getLineNo());
2073 
2074   Stream.EmitRecord(bitc::METADATA_COMMON_BLOCK, Record, Abbrev);
2075   Record.clear();
2076 }
2077 
2078 void ModuleBitcodeWriter::writeDINamespace(const DINamespace *N,
2079                                            SmallVectorImpl<uint64_t> &Record,
2080                                            unsigned Abbrev) {
2081   Record.push_back(N->isDistinct() | N->getExportSymbols() << 1);
2082   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2083   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2084 
2085   Stream.EmitRecord(bitc::METADATA_NAMESPACE, Record, Abbrev);
2086   Record.clear();
2087 }
2088 
2089 void ModuleBitcodeWriter::writeDIMacro(const DIMacro *N,
2090                                        SmallVectorImpl<uint64_t> &Record,
2091                                        unsigned Abbrev) {
2092   Record.push_back(N->isDistinct());
2093   Record.push_back(N->getMacinfoType());
2094   Record.push_back(N->getLine());
2095   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2096   Record.push_back(VE.getMetadataOrNullID(N->getRawValue()));
2097 
2098   Stream.EmitRecord(bitc::METADATA_MACRO, Record, Abbrev);
2099   Record.clear();
2100 }
2101 
2102 void ModuleBitcodeWriter::writeDIMacroFile(const DIMacroFile *N,
2103                                            SmallVectorImpl<uint64_t> &Record,
2104                                            unsigned Abbrev) {
2105   Record.push_back(N->isDistinct());
2106   Record.push_back(N->getMacinfoType());
2107   Record.push_back(N->getLine());
2108   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2109   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
2110 
2111   Stream.EmitRecord(bitc::METADATA_MACRO_FILE, Record, Abbrev);
2112   Record.clear();
2113 }
2114 
2115 void ModuleBitcodeWriter::writeDIArgList(const DIArgList *N,
2116                                          SmallVectorImpl<uint64_t> &Record) {
2117   Record.reserve(N->getArgs().size());
2118   for (ValueAsMetadata *MD : N->getArgs())
2119     Record.push_back(VE.getMetadataID(MD));
2120 
2121   Stream.EmitRecord(bitc::METADATA_ARG_LIST, Record);
2122   Record.clear();
2123 }
2124 
2125 void ModuleBitcodeWriter::writeDIModule(const DIModule *N,
2126                                         SmallVectorImpl<uint64_t> &Record,
2127                                         unsigned Abbrev) {
2128   Record.push_back(N->isDistinct());
2129   for (auto &I : N->operands())
2130     Record.push_back(VE.getMetadataOrNullID(I));
2131   Record.push_back(N->getLineNo());
2132   Record.push_back(N->getIsDecl());
2133 
2134   Stream.EmitRecord(bitc::METADATA_MODULE, Record, Abbrev);
2135   Record.clear();
2136 }
2137 
2138 void ModuleBitcodeWriter::writeDIAssignID(const DIAssignID *N,
2139                                           SmallVectorImpl<uint64_t> &Record,
2140                                           unsigned Abbrev) {
2141   // There are no arguments for this metadata type.
2142   Record.push_back(N->isDistinct());
2143   Stream.EmitRecord(bitc::METADATA_ASSIGN_ID, Record, Abbrev);
2144   Record.clear();
2145 }
2146 
2147 void ModuleBitcodeWriter::writeDITemplateTypeParameter(
2148     const DITemplateTypeParameter *N, SmallVectorImpl<uint64_t> &Record,
2149     unsigned Abbrev) {
2150   Record.push_back(N->isDistinct());
2151   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2152   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2153   Record.push_back(N->isDefault());
2154 
2155   Stream.EmitRecord(bitc::METADATA_TEMPLATE_TYPE, Record, Abbrev);
2156   Record.clear();
2157 }
2158 
2159 void ModuleBitcodeWriter::writeDITemplateValueParameter(
2160     const DITemplateValueParameter *N, SmallVectorImpl<uint64_t> &Record,
2161     unsigned Abbrev) {
2162   Record.push_back(N->isDistinct());
2163   Record.push_back(N->getTag());
2164   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2165   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2166   Record.push_back(N->isDefault());
2167   Record.push_back(VE.getMetadataOrNullID(N->getValue()));
2168 
2169   Stream.EmitRecord(bitc::METADATA_TEMPLATE_VALUE, Record, Abbrev);
2170   Record.clear();
2171 }
2172 
2173 void ModuleBitcodeWriter::writeDIGlobalVariable(
2174     const DIGlobalVariable *N, SmallVectorImpl<uint64_t> &Record,
2175     unsigned Abbrev) {
2176   const uint64_t Version = 2 << 1;
2177   Record.push_back((uint64_t)N->isDistinct() | Version);
2178   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2179   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2180   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
2181   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2182   Record.push_back(N->getLine());
2183   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2184   Record.push_back(N->isLocalToUnit());
2185   Record.push_back(N->isDefinition());
2186   Record.push_back(VE.getMetadataOrNullID(N->getStaticDataMemberDeclaration()));
2187   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams()));
2188   Record.push_back(N->getAlignInBits());
2189   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
2190 
2191   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR, Record, Abbrev);
2192   Record.clear();
2193 }
2194 
2195 void ModuleBitcodeWriter::writeDILocalVariable(
2196     const DILocalVariable *N, SmallVectorImpl<uint64_t> &Record,
2197     unsigned Abbrev) {
2198   // In order to support all possible bitcode formats in BitcodeReader we need
2199   // to distinguish the following cases:
2200   // 1) Record has no artificial tag (Record[1]),
2201   //   has no obsolete inlinedAt field (Record[9]).
2202   //   In this case Record size will be 8, HasAlignment flag is false.
2203   // 2) Record has artificial tag (Record[1]),
2204   //   has no obsolete inlignedAt field (Record[9]).
2205   //   In this case Record size will be 9, HasAlignment flag is false.
2206   // 3) Record has both artificial tag (Record[1]) and
2207   //   obsolete inlignedAt field (Record[9]).
2208   //   In this case Record size will be 10, HasAlignment flag is false.
2209   // 4) Record has neither artificial tag, nor inlignedAt field, but
2210   //   HasAlignment flag is true and Record[8] contains alignment value.
2211   const uint64_t HasAlignmentFlag = 1 << 1;
2212   Record.push_back((uint64_t)N->isDistinct() | HasAlignmentFlag);
2213   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2214   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2215   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2216   Record.push_back(N->getLine());
2217   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2218   Record.push_back(N->getArg());
2219   Record.push_back(N->getFlags());
2220   Record.push_back(N->getAlignInBits());
2221   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
2222 
2223   Stream.EmitRecord(bitc::METADATA_LOCAL_VAR, Record, Abbrev);
2224   Record.clear();
2225 }
2226 
2227 void ModuleBitcodeWriter::writeDILabel(
2228     const DILabel *N, SmallVectorImpl<uint64_t> &Record,
2229     unsigned Abbrev) {
2230   Record.push_back((uint64_t)N->isDistinct());
2231   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2232   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2233   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2234   Record.push_back(N->getLine());
2235 
2236   Stream.EmitRecord(bitc::METADATA_LABEL, Record, Abbrev);
2237   Record.clear();
2238 }
2239 
2240 void ModuleBitcodeWriter::writeDIExpression(const DIExpression *N,
2241                                             SmallVectorImpl<uint64_t> &Record,
2242                                             unsigned Abbrev) {
2243   Record.reserve(N->getElements().size() + 1);
2244   const uint64_t Version = 3 << 1;
2245   Record.push_back((uint64_t)N->isDistinct() | Version);
2246   Record.append(N->elements_begin(), N->elements_end());
2247 
2248   Stream.EmitRecord(bitc::METADATA_EXPRESSION, Record, Abbrev);
2249   Record.clear();
2250 }
2251 
2252 void ModuleBitcodeWriter::writeDIGlobalVariableExpression(
2253     const DIGlobalVariableExpression *N, SmallVectorImpl<uint64_t> &Record,
2254     unsigned Abbrev) {
2255   Record.push_back(N->isDistinct());
2256   Record.push_back(VE.getMetadataOrNullID(N->getVariable()));
2257   Record.push_back(VE.getMetadataOrNullID(N->getExpression()));
2258 
2259   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR_EXPR, Record, Abbrev);
2260   Record.clear();
2261 }
2262 
2263 void ModuleBitcodeWriter::writeDIObjCProperty(const DIObjCProperty *N,
2264                                               SmallVectorImpl<uint64_t> &Record,
2265                                               unsigned Abbrev) {
2266   Record.push_back(N->isDistinct());
2267   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2268   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2269   Record.push_back(N->getLine());
2270   Record.push_back(VE.getMetadataOrNullID(N->getRawSetterName()));
2271   Record.push_back(VE.getMetadataOrNullID(N->getRawGetterName()));
2272   Record.push_back(N->getAttributes());
2273   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2274 
2275   Stream.EmitRecord(bitc::METADATA_OBJC_PROPERTY, Record, Abbrev);
2276   Record.clear();
2277 }
2278 
2279 void ModuleBitcodeWriter::writeDIImportedEntity(
2280     const DIImportedEntity *N, SmallVectorImpl<uint64_t> &Record,
2281     unsigned Abbrev) {
2282   Record.push_back(N->isDistinct());
2283   Record.push_back(N->getTag());
2284   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2285   Record.push_back(VE.getMetadataOrNullID(N->getEntity()));
2286   Record.push_back(N->getLine());
2287   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2288   Record.push_back(VE.getMetadataOrNullID(N->getRawFile()));
2289   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
2290 
2291   Stream.EmitRecord(bitc::METADATA_IMPORTED_ENTITY, Record, Abbrev);
2292   Record.clear();
2293 }
2294 
2295 unsigned ModuleBitcodeWriter::createNamedMetadataAbbrev() {
2296   auto Abbv = std::make_shared<BitCodeAbbrev>();
2297   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
2298   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2299   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2300   return Stream.EmitAbbrev(std::move(Abbv));
2301 }
2302 
2303 void ModuleBitcodeWriter::writeNamedMetadata(
2304     SmallVectorImpl<uint64_t> &Record) {
2305   if (M.named_metadata_empty())
2306     return;
2307 
2308   unsigned Abbrev = createNamedMetadataAbbrev();
2309   for (const NamedMDNode &NMD : M.named_metadata()) {
2310     // Write name.
2311     StringRef Str = NMD.getName();
2312     Record.append(Str.bytes_begin(), Str.bytes_end());
2313     Stream.EmitRecord(bitc::METADATA_NAME, Record, Abbrev);
2314     Record.clear();
2315 
2316     // Write named metadata operands.
2317     for (const MDNode *N : NMD.operands())
2318       Record.push_back(VE.getMetadataID(N));
2319     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
2320     Record.clear();
2321   }
2322 }
2323 
2324 unsigned ModuleBitcodeWriter::createMetadataStringsAbbrev() {
2325   auto Abbv = std::make_shared<BitCodeAbbrev>();
2326   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRINGS));
2327   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // # of strings
2328   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // offset to chars
2329   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
2330   return Stream.EmitAbbrev(std::move(Abbv));
2331 }
2332 
2333 /// Write out a record for MDString.
2334 ///
2335 /// All the metadata strings in a metadata block are emitted in a single
2336 /// record.  The sizes and strings themselves are shoved into a blob.
2337 void ModuleBitcodeWriter::writeMetadataStrings(
2338     ArrayRef<const Metadata *> Strings, SmallVectorImpl<uint64_t> &Record) {
2339   if (Strings.empty())
2340     return;
2341 
2342   // Start the record with the number of strings.
2343   Record.push_back(bitc::METADATA_STRINGS);
2344   Record.push_back(Strings.size());
2345 
2346   // Emit the sizes of the strings in the blob.
2347   SmallString<256> Blob;
2348   {
2349     BitstreamWriter W(Blob);
2350     for (const Metadata *MD : Strings)
2351       W.EmitVBR(cast<MDString>(MD)->getLength(), 6);
2352     W.FlushToWord();
2353   }
2354 
2355   // Add the offset to the strings to the record.
2356   Record.push_back(Blob.size());
2357 
2358   // Add the strings to the blob.
2359   for (const Metadata *MD : Strings)
2360     Blob.append(cast<MDString>(MD)->getString());
2361 
2362   // Emit the final record.
2363   Stream.EmitRecordWithBlob(createMetadataStringsAbbrev(), Record, Blob);
2364   Record.clear();
2365 }
2366 
2367 // Generates an enum to use as an index in the Abbrev array of Metadata record.
2368 enum MetadataAbbrev : unsigned {
2369 #define HANDLE_MDNODE_LEAF(CLASS) CLASS##AbbrevID,
2370 #include "llvm/IR/Metadata.def"
2371   LastPlusOne
2372 };
2373 
2374 void ModuleBitcodeWriter::writeMetadataRecords(
2375     ArrayRef<const Metadata *> MDs, SmallVectorImpl<uint64_t> &Record,
2376     std::vector<unsigned> *MDAbbrevs, std::vector<uint64_t> *IndexPos) {
2377   if (MDs.empty())
2378     return;
2379 
2380   // Initialize MDNode abbreviations.
2381 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
2382 #include "llvm/IR/Metadata.def"
2383 
2384   for (const Metadata *MD : MDs) {
2385     if (IndexPos)
2386       IndexPos->push_back(Stream.GetCurrentBitNo());
2387     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
2388       assert(N->isResolved() && "Expected forward references to be resolved");
2389 
2390       switch (N->getMetadataID()) {
2391       default:
2392         llvm_unreachable("Invalid MDNode subclass");
2393 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
2394   case Metadata::CLASS##Kind:                                                  \
2395     if (MDAbbrevs)                                                             \
2396       write##CLASS(cast<CLASS>(N), Record,                                     \
2397                    (*MDAbbrevs)[MetadataAbbrev::CLASS##AbbrevID]);             \
2398     else                                                                       \
2399       write##CLASS(cast<CLASS>(N), Record, CLASS##Abbrev);                     \
2400     continue;
2401 #include "llvm/IR/Metadata.def"
2402       }
2403     }
2404     if (auto *AL = dyn_cast<DIArgList>(MD)) {
2405       writeDIArgList(AL, Record);
2406       continue;
2407     }
2408     writeValueAsMetadata(cast<ValueAsMetadata>(MD), Record);
2409   }
2410 }
2411 
2412 void ModuleBitcodeWriter::writeModuleMetadata() {
2413   if (!VE.hasMDs() && M.named_metadata_empty())
2414     return;
2415 
2416   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 4);
2417   SmallVector<uint64_t, 64> Record;
2418 
2419   // Emit all abbrevs upfront, so that the reader can jump in the middle of the
2420   // block and load any metadata.
2421   std::vector<unsigned> MDAbbrevs;
2422 
2423   MDAbbrevs.resize(MetadataAbbrev::LastPlusOne);
2424   MDAbbrevs[MetadataAbbrev::DILocationAbbrevID] = createDILocationAbbrev();
2425   MDAbbrevs[MetadataAbbrev::GenericDINodeAbbrevID] =
2426       createGenericDINodeAbbrev();
2427 
2428   auto Abbv = std::make_shared<BitCodeAbbrev>();
2429   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX_OFFSET));
2430   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2431   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2432   unsigned OffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2433 
2434   Abbv = std::make_shared<BitCodeAbbrev>();
2435   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX));
2436   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2437   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2438   unsigned IndexAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2439 
2440   // Emit MDStrings together upfront.
2441   writeMetadataStrings(VE.getMDStrings(), Record);
2442 
2443   // We only emit an index for the metadata record if we have more than a given
2444   // (naive) threshold of metadatas, otherwise it is not worth it.
2445   if (VE.getNonMDStrings().size() > IndexThreshold) {
2446     // Write a placeholder value in for the offset of the metadata index,
2447     // which is written after the records, so that it can include
2448     // the offset of each entry. The placeholder offset will be
2449     // updated after all records are emitted.
2450     uint64_t Vals[] = {0, 0};
2451     Stream.EmitRecord(bitc::METADATA_INDEX_OFFSET, Vals, OffsetAbbrev);
2452   }
2453 
2454   // Compute and save the bit offset to the current position, which will be
2455   // patched when we emit the index later. We can simply subtract the 64-bit
2456   // fixed size from the current bit number to get the location to backpatch.
2457   uint64_t IndexOffsetRecordBitPos = Stream.GetCurrentBitNo();
2458 
2459   // This index will contain the bitpos for each individual record.
2460   std::vector<uint64_t> IndexPos;
2461   IndexPos.reserve(VE.getNonMDStrings().size());
2462 
2463   // Write all the records
2464   writeMetadataRecords(VE.getNonMDStrings(), Record, &MDAbbrevs, &IndexPos);
2465 
2466   if (VE.getNonMDStrings().size() > IndexThreshold) {
2467     // Now that we have emitted all the records we will emit the index. But
2468     // first
2469     // backpatch the forward reference so that the reader can skip the records
2470     // efficiently.
2471     Stream.BackpatchWord64(IndexOffsetRecordBitPos - 64,
2472                            Stream.GetCurrentBitNo() - IndexOffsetRecordBitPos);
2473 
2474     // Delta encode the index.
2475     uint64_t PreviousValue = IndexOffsetRecordBitPos;
2476     for (auto &Elt : IndexPos) {
2477       auto EltDelta = Elt - PreviousValue;
2478       PreviousValue = Elt;
2479       Elt = EltDelta;
2480     }
2481     // Emit the index record.
2482     Stream.EmitRecord(bitc::METADATA_INDEX, IndexPos, IndexAbbrev);
2483     IndexPos.clear();
2484   }
2485 
2486   // Write the named metadata now.
2487   writeNamedMetadata(Record);
2488 
2489   auto AddDeclAttachedMetadata = [&](const GlobalObject &GO) {
2490     SmallVector<uint64_t, 4> Record;
2491     Record.push_back(VE.getValueID(&GO));
2492     pushGlobalMetadataAttachment(Record, GO);
2493     Stream.EmitRecord(bitc::METADATA_GLOBAL_DECL_ATTACHMENT, Record);
2494   };
2495   for (const Function &F : M)
2496     if (F.isDeclaration() && F.hasMetadata())
2497       AddDeclAttachedMetadata(F);
2498   // FIXME: Only store metadata for declarations here, and move data for global
2499   // variable definitions to a separate block (PR28134).
2500   for (const GlobalVariable &GV : M.globals())
2501     if (GV.hasMetadata())
2502       AddDeclAttachedMetadata(GV);
2503 
2504   Stream.ExitBlock();
2505 }
2506 
2507 void ModuleBitcodeWriter::writeFunctionMetadata(const Function &F) {
2508   if (!VE.hasMDs())
2509     return;
2510 
2511   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
2512   SmallVector<uint64_t, 64> Record;
2513   writeMetadataStrings(VE.getMDStrings(), Record);
2514   writeMetadataRecords(VE.getNonMDStrings(), Record);
2515   Stream.ExitBlock();
2516 }
2517 
2518 void ModuleBitcodeWriter::pushGlobalMetadataAttachment(
2519     SmallVectorImpl<uint64_t> &Record, const GlobalObject &GO) {
2520   // [n x [id, mdnode]]
2521   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2522   GO.getAllMetadata(MDs);
2523   for (const auto &I : MDs) {
2524     Record.push_back(I.first);
2525     Record.push_back(VE.getMetadataID(I.second));
2526   }
2527 }
2528 
2529 void ModuleBitcodeWriter::writeFunctionMetadataAttachment(const Function &F) {
2530   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
2531 
2532   SmallVector<uint64_t, 64> Record;
2533 
2534   if (F.hasMetadata()) {
2535     pushGlobalMetadataAttachment(Record, F);
2536     Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2537     Record.clear();
2538   }
2539 
2540   // Write metadata attachments
2541   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
2542   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2543   for (const BasicBlock &BB : F)
2544     for (const Instruction &I : BB) {
2545       MDs.clear();
2546       I.getAllMetadataOtherThanDebugLoc(MDs);
2547 
2548       // If no metadata, ignore instruction.
2549       if (MDs.empty()) continue;
2550 
2551       Record.push_back(VE.getInstructionID(&I));
2552 
2553       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
2554         Record.push_back(MDs[i].first);
2555         Record.push_back(VE.getMetadataID(MDs[i].second));
2556       }
2557       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2558       Record.clear();
2559     }
2560 
2561   Stream.ExitBlock();
2562 }
2563 
2564 void ModuleBitcodeWriter::writeModuleMetadataKinds() {
2565   SmallVector<uint64_t, 64> Record;
2566 
2567   // Write metadata kinds
2568   // METADATA_KIND - [n x [id, name]]
2569   SmallVector<StringRef, 8> Names;
2570   M.getMDKindNames(Names);
2571 
2572   if (Names.empty()) return;
2573 
2574   Stream.EnterSubblock(bitc::METADATA_KIND_BLOCK_ID, 3);
2575 
2576   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
2577     Record.push_back(MDKindID);
2578     StringRef KName = Names[MDKindID];
2579     Record.append(KName.begin(), KName.end());
2580 
2581     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
2582     Record.clear();
2583   }
2584 
2585   Stream.ExitBlock();
2586 }
2587 
2588 void ModuleBitcodeWriter::writeOperandBundleTags() {
2589   // Write metadata kinds
2590   //
2591   // OPERAND_BUNDLE_TAGS_BLOCK_ID : N x OPERAND_BUNDLE_TAG
2592   //
2593   // OPERAND_BUNDLE_TAG - [strchr x N]
2594 
2595   SmallVector<StringRef, 8> Tags;
2596   M.getOperandBundleTags(Tags);
2597 
2598   if (Tags.empty())
2599     return;
2600 
2601   Stream.EnterSubblock(bitc::OPERAND_BUNDLE_TAGS_BLOCK_ID, 3);
2602 
2603   SmallVector<uint64_t, 64> Record;
2604 
2605   for (auto Tag : Tags) {
2606     Record.append(Tag.begin(), Tag.end());
2607 
2608     Stream.EmitRecord(bitc::OPERAND_BUNDLE_TAG, Record, 0);
2609     Record.clear();
2610   }
2611 
2612   Stream.ExitBlock();
2613 }
2614 
2615 void ModuleBitcodeWriter::writeSyncScopeNames() {
2616   SmallVector<StringRef, 8> SSNs;
2617   M.getContext().getSyncScopeNames(SSNs);
2618   if (SSNs.empty())
2619     return;
2620 
2621   Stream.EnterSubblock(bitc::SYNC_SCOPE_NAMES_BLOCK_ID, 2);
2622 
2623   SmallVector<uint64_t, 64> Record;
2624   for (auto SSN : SSNs) {
2625     Record.append(SSN.begin(), SSN.end());
2626     Stream.EmitRecord(bitc::SYNC_SCOPE_NAME, Record, 0);
2627     Record.clear();
2628   }
2629 
2630   Stream.ExitBlock();
2631 }
2632 
2633 void ModuleBitcodeWriter::writeConstants(unsigned FirstVal, unsigned LastVal,
2634                                          bool isGlobal) {
2635   if (FirstVal == LastVal) return;
2636 
2637   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
2638 
2639   unsigned AggregateAbbrev = 0;
2640   unsigned String8Abbrev = 0;
2641   unsigned CString7Abbrev = 0;
2642   unsigned CString6Abbrev = 0;
2643   // If this is a constant pool for the module, emit module-specific abbrevs.
2644   if (isGlobal) {
2645     // Abbrev for CST_CODE_AGGREGATE.
2646     auto Abbv = std::make_shared<BitCodeAbbrev>();
2647     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
2648     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2649     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
2650     AggregateAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2651 
2652     // Abbrev for CST_CODE_STRING.
2653     Abbv = std::make_shared<BitCodeAbbrev>();
2654     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
2655     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2656     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2657     String8Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2658     // Abbrev for CST_CODE_CSTRING.
2659     Abbv = std::make_shared<BitCodeAbbrev>();
2660     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2661     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2662     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2663     CString7Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2664     // Abbrev for CST_CODE_CSTRING.
2665     Abbv = std::make_shared<BitCodeAbbrev>();
2666     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2667     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2668     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2669     CString6Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2670   }
2671 
2672   SmallVector<uint64_t, 64> Record;
2673 
2674   const ValueEnumerator::ValueList &Vals = VE.getValues();
2675   Type *LastTy = nullptr;
2676   for (unsigned i = FirstVal; i != LastVal; ++i) {
2677     const Value *V = Vals[i].first;
2678     // If we need to switch types, do so now.
2679     if (V->getType() != LastTy) {
2680       LastTy = V->getType();
2681       Record.push_back(VE.getTypeID(LastTy));
2682       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
2683                         CONSTANTS_SETTYPE_ABBREV);
2684       Record.clear();
2685     }
2686 
2687     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
2688       Record.push_back(VE.getTypeID(IA->getFunctionType()));
2689       Record.push_back(
2690           unsigned(IA->hasSideEffects()) | unsigned(IA->isAlignStack()) << 1 |
2691           unsigned(IA->getDialect() & 1) << 2 | unsigned(IA->canThrow()) << 3);
2692 
2693       // Add the asm string.
2694       const std::string &AsmStr = IA->getAsmString();
2695       Record.push_back(AsmStr.size());
2696       Record.append(AsmStr.begin(), AsmStr.end());
2697 
2698       // Add the constraint string.
2699       const std::string &ConstraintStr = IA->getConstraintString();
2700       Record.push_back(ConstraintStr.size());
2701       Record.append(ConstraintStr.begin(), ConstraintStr.end());
2702       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
2703       Record.clear();
2704       continue;
2705     }
2706     const Constant *C = cast<Constant>(V);
2707     unsigned Code = -1U;
2708     unsigned AbbrevToUse = 0;
2709     if (C->isNullValue()) {
2710       Code = bitc::CST_CODE_NULL;
2711     } else if (isa<PoisonValue>(C)) {
2712       Code = bitc::CST_CODE_POISON;
2713     } else if (isa<UndefValue>(C)) {
2714       Code = bitc::CST_CODE_UNDEF;
2715     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
2716       if (IV->getBitWidth() <= 64) {
2717         uint64_t V = IV->getSExtValue();
2718         emitSignedInt64(Record, V);
2719         Code = bitc::CST_CODE_INTEGER;
2720         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
2721       } else {                             // Wide integers, > 64 bits in size.
2722         emitWideAPInt(Record, IV->getValue());
2723         Code = bitc::CST_CODE_WIDE_INTEGER;
2724       }
2725     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
2726       Code = bitc::CST_CODE_FLOAT;
2727       Type *Ty = CFP->getType()->getScalarType();
2728       if (Ty->isHalfTy() || Ty->isBFloatTy() || Ty->isFloatTy() ||
2729           Ty->isDoubleTy()) {
2730         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
2731       } else if (Ty->isX86_FP80Ty()) {
2732         // api needed to prevent premature destruction
2733         // bits are not in the same order as a normal i80 APInt, compensate.
2734         APInt api = CFP->getValueAPF().bitcastToAPInt();
2735         const uint64_t *p = api.getRawData();
2736         Record.push_back((p[1] << 48) | (p[0] >> 16));
2737         Record.push_back(p[0] & 0xffffLL);
2738       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
2739         APInt api = CFP->getValueAPF().bitcastToAPInt();
2740         const uint64_t *p = api.getRawData();
2741         Record.push_back(p[0]);
2742         Record.push_back(p[1]);
2743       } else {
2744         assert(0 && "Unknown FP type!");
2745       }
2746     } else if (isa<ConstantDataSequential>(C) &&
2747                cast<ConstantDataSequential>(C)->isString()) {
2748       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
2749       // Emit constant strings specially.
2750       unsigned NumElts = Str->getNumElements();
2751       // If this is a null-terminated string, use the denser CSTRING encoding.
2752       if (Str->isCString()) {
2753         Code = bitc::CST_CODE_CSTRING;
2754         --NumElts;  // Don't encode the null, which isn't allowed by char6.
2755       } else {
2756         Code = bitc::CST_CODE_STRING;
2757         AbbrevToUse = String8Abbrev;
2758       }
2759       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
2760       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
2761       for (unsigned i = 0; i != NumElts; ++i) {
2762         unsigned char V = Str->getElementAsInteger(i);
2763         Record.push_back(V);
2764         isCStr7 &= (V & 128) == 0;
2765         if (isCStrChar6)
2766           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
2767       }
2768 
2769       if (isCStrChar6)
2770         AbbrevToUse = CString6Abbrev;
2771       else if (isCStr7)
2772         AbbrevToUse = CString7Abbrev;
2773     } else if (const ConstantDataSequential *CDS =
2774                   dyn_cast<ConstantDataSequential>(C)) {
2775       Code = bitc::CST_CODE_DATA;
2776       Type *EltTy = CDS->getElementType();
2777       if (isa<IntegerType>(EltTy)) {
2778         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2779           Record.push_back(CDS->getElementAsInteger(i));
2780       } else {
2781         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2782           Record.push_back(
2783               CDS->getElementAsAPFloat(i).bitcastToAPInt().getLimitedValue());
2784       }
2785     } else if (isa<ConstantAggregate>(C)) {
2786       Code = bitc::CST_CODE_AGGREGATE;
2787       for (const Value *Op : C->operands())
2788         Record.push_back(VE.getValueID(Op));
2789       AbbrevToUse = AggregateAbbrev;
2790     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
2791       switch (CE->getOpcode()) {
2792       default:
2793         if (Instruction::isCast(CE->getOpcode())) {
2794           Code = bitc::CST_CODE_CE_CAST;
2795           Record.push_back(getEncodedCastOpcode(CE->getOpcode()));
2796           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2797           Record.push_back(VE.getValueID(C->getOperand(0)));
2798           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
2799         } else {
2800           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
2801           Code = bitc::CST_CODE_CE_BINOP;
2802           Record.push_back(getEncodedBinaryOpcode(CE->getOpcode()));
2803           Record.push_back(VE.getValueID(C->getOperand(0)));
2804           Record.push_back(VE.getValueID(C->getOperand(1)));
2805           uint64_t Flags = getOptimizationFlags(CE);
2806           if (Flags != 0)
2807             Record.push_back(Flags);
2808         }
2809         break;
2810       case Instruction::FNeg: {
2811         assert(CE->getNumOperands() == 1 && "Unknown constant expr!");
2812         Code = bitc::CST_CODE_CE_UNOP;
2813         Record.push_back(getEncodedUnaryOpcode(CE->getOpcode()));
2814         Record.push_back(VE.getValueID(C->getOperand(0)));
2815         uint64_t Flags = getOptimizationFlags(CE);
2816         if (Flags != 0)
2817           Record.push_back(Flags);
2818         break;
2819       }
2820       case Instruction::GetElementPtr: {
2821         Code = bitc::CST_CODE_CE_GEP;
2822         const auto *GO = cast<GEPOperator>(C);
2823         Record.push_back(VE.getTypeID(GO->getSourceElementType()));
2824         Record.push_back(getOptimizationFlags(GO));
2825         if (std::optional<ConstantRange> Range = GO->getInRange()) {
2826           Code = bitc::CST_CODE_CE_GEP_WITH_INRANGE;
2827           emitConstantRange(Record, *Range, /*EmitBitWidth=*/true);
2828         }
2829         for (const Value *Op : CE->operands()) {
2830           Record.push_back(VE.getTypeID(Op->getType()));
2831           Record.push_back(VE.getValueID(Op));
2832         }
2833         break;
2834       }
2835       case Instruction::ExtractElement:
2836         Code = bitc::CST_CODE_CE_EXTRACTELT;
2837         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2838         Record.push_back(VE.getValueID(C->getOperand(0)));
2839         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
2840         Record.push_back(VE.getValueID(C->getOperand(1)));
2841         break;
2842       case Instruction::InsertElement:
2843         Code = bitc::CST_CODE_CE_INSERTELT;
2844         Record.push_back(VE.getValueID(C->getOperand(0)));
2845         Record.push_back(VE.getValueID(C->getOperand(1)));
2846         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
2847         Record.push_back(VE.getValueID(C->getOperand(2)));
2848         break;
2849       case Instruction::ShuffleVector:
2850         // If the return type and argument types are the same, this is a
2851         // standard shufflevector instruction.  If the types are different,
2852         // then the shuffle is widening or truncating the input vectors, and
2853         // the argument type must also be encoded.
2854         if (C->getType() == C->getOperand(0)->getType()) {
2855           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
2856         } else {
2857           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
2858           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2859         }
2860         Record.push_back(VE.getValueID(C->getOperand(0)));
2861         Record.push_back(VE.getValueID(C->getOperand(1)));
2862         Record.push_back(VE.getValueID(CE->getShuffleMaskForBitcode()));
2863         break;
2864       }
2865     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
2866       Code = bitc::CST_CODE_BLOCKADDRESS;
2867       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
2868       Record.push_back(VE.getValueID(BA->getFunction()));
2869       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
2870     } else if (const auto *Equiv = dyn_cast<DSOLocalEquivalent>(C)) {
2871       Code = bitc::CST_CODE_DSO_LOCAL_EQUIVALENT;
2872       Record.push_back(VE.getTypeID(Equiv->getGlobalValue()->getType()));
2873       Record.push_back(VE.getValueID(Equiv->getGlobalValue()));
2874     } else if (const auto *NC = dyn_cast<NoCFIValue>(C)) {
2875       Code = bitc::CST_CODE_NO_CFI_VALUE;
2876       Record.push_back(VE.getTypeID(NC->getGlobalValue()->getType()));
2877       Record.push_back(VE.getValueID(NC->getGlobalValue()));
2878     } else if (const auto *CPA = dyn_cast<ConstantPtrAuth>(C)) {
2879       Code = bitc::CST_CODE_PTRAUTH;
2880       Record.push_back(VE.getValueID(CPA->getPointer()));
2881       Record.push_back(VE.getValueID(CPA->getKey()));
2882       Record.push_back(VE.getValueID(CPA->getDiscriminator()));
2883       Record.push_back(VE.getValueID(CPA->getAddrDiscriminator()));
2884     } else {
2885 #ifndef NDEBUG
2886       C->dump();
2887 #endif
2888       llvm_unreachable("Unknown constant!");
2889     }
2890     Stream.EmitRecord(Code, Record, AbbrevToUse);
2891     Record.clear();
2892   }
2893 
2894   Stream.ExitBlock();
2895 }
2896 
2897 void ModuleBitcodeWriter::writeModuleConstants() {
2898   const ValueEnumerator::ValueList &Vals = VE.getValues();
2899 
2900   // Find the first constant to emit, which is the first non-globalvalue value.
2901   // We know globalvalues have been emitted by WriteModuleInfo.
2902   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
2903     if (!isa<GlobalValue>(Vals[i].first)) {
2904       writeConstants(i, Vals.size(), true);
2905       return;
2906     }
2907   }
2908 }
2909 
2910 /// pushValueAndType - The file has to encode both the value and type id for
2911 /// many values, because we need to know what type to create for forward
2912 /// references.  However, most operands are not forward references, so this type
2913 /// field is not needed.
2914 ///
2915 /// This function adds V's value ID to Vals.  If the value ID is higher than the
2916 /// instruction ID, then it is a forward reference, and it also includes the
2917 /// type ID.  The value ID that is written is encoded relative to the InstID.
2918 bool ModuleBitcodeWriter::pushValueAndType(const Value *V, unsigned InstID,
2919                                            SmallVectorImpl<unsigned> &Vals) {
2920   unsigned ValID = VE.getValueID(V);
2921   // Make encoding relative to the InstID.
2922   Vals.push_back(InstID - ValID);
2923   if (ValID >= InstID) {
2924     Vals.push_back(VE.getTypeID(V->getType()));
2925     return true;
2926   }
2927   return false;
2928 }
2929 
2930 void ModuleBitcodeWriter::writeOperandBundles(const CallBase &CS,
2931                                               unsigned InstID) {
2932   SmallVector<unsigned, 64> Record;
2933   LLVMContext &C = CS.getContext();
2934 
2935   for (unsigned i = 0, e = CS.getNumOperandBundles(); i != e; ++i) {
2936     const auto &Bundle = CS.getOperandBundleAt(i);
2937     Record.push_back(C.getOperandBundleTagID(Bundle.getTagName()));
2938 
2939     for (auto &Input : Bundle.Inputs)
2940       pushValueAndType(Input, InstID, Record);
2941 
2942     Stream.EmitRecord(bitc::FUNC_CODE_OPERAND_BUNDLE, Record);
2943     Record.clear();
2944   }
2945 }
2946 
2947 /// pushValue - Like pushValueAndType, but where the type of the value is
2948 /// omitted (perhaps it was already encoded in an earlier operand).
2949 void ModuleBitcodeWriter::pushValue(const Value *V, unsigned InstID,
2950                                     SmallVectorImpl<unsigned> &Vals) {
2951   unsigned ValID = VE.getValueID(V);
2952   Vals.push_back(InstID - ValID);
2953 }
2954 
2955 void ModuleBitcodeWriter::pushValueSigned(const Value *V, unsigned InstID,
2956                                           SmallVectorImpl<uint64_t> &Vals) {
2957   unsigned ValID = VE.getValueID(V);
2958   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
2959   emitSignedInt64(Vals, diff);
2960 }
2961 
2962 /// WriteInstruction - Emit an instruction to the specified stream.
2963 void ModuleBitcodeWriter::writeInstruction(const Instruction &I,
2964                                            unsigned InstID,
2965                                            SmallVectorImpl<unsigned> &Vals) {
2966   unsigned Code = 0;
2967   unsigned AbbrevToUse = 0;
2968   VE.setInstructionID(&I);
2969   switch (I.getOpcode()) {
2970   default:
2971     if (Instruction::isCast(I.getOpcode())) {
2972       Code = bitc::FUNC_CODE_INST_CAST;
2973       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2974         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
2975       Vals.push_back(VE.getTypeID(I.getType()));
2976       Vals.push_back(getEncodedCastOpcode(I.getOpcode()));
2977       uint64_t Flags = getOptimizationFlags(&I);
2978       if (Flags != 0) {
2979         if (AbbrevToUse == FUNCTION_INST_CAST_ABBREV)
2980           AbbrevToUse = FUNCTION_INST_CAST_FLAGS_ABBREV;
2981         Vals.push_back(Flags);
2982       }
2983     } else {
2984       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
2985       Code = bitc::FUNC_CODE_INST_BINOP;
2986       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2987         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
2988       pushValue(I.getOperand(1), InstID, Vals);
2989       Vals.push_back(getEncodedBinaryOpcode(I.getOpcode()));
2990       uint64_t Flags = getOptimizationFlags(&I);
2991       if (Flags != 0) {
2992         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
2993           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
2994         Vals.push_back(Flags);
2995       }
2996     }
2997     break;
2998   case Instruction::FNeg: {
2999     Code = bitc::FUNC_CODE_INST_UNOP;
3000     if (!pushValueAndType(I.getOperand(0), InstID, Vals))
3001       AbbrevToUse = FUNCTION_INST_UNOP_ABBREV;
3002     Vals.push_back(getEncodedUnaryOpcode(I.getOpcode()));
3003     uint64_t Flags = getOptimizationFlags(&I);
3004     if (Flags != 0) {
3005       if (AbbrevToUse == FUNCTION_INST_UNOP_ABBREV)
3006         AbbrevToUse = FUNCTION_INST_UNOP_FLAGS_ABBREV;
3007       Vals.push_back(Flags);
3008     }
3009     break;
3010   }
3011   case Instruction::GetElementPtr: {
3012     Code = bitc::FUNC_CODE_INST_GEP;
3013     AbbrevToUse = FUNCTION_INST_GEP_ABBREV;
3014     auto &GEPInst = cast<GetElementPtrInst>(I);
3015     Vals.push_back(getOptimizationFlags(&I));
3016     Vals.push_back(VE.getTypeID(GEPInst.getSourceElementType()));
3017     for (const Value *Op : I.operands())
3018       pushValueAndType(Op, InstID, Vals);
3019     break;
3020   }
3021   case Instruction::ExtractValue: {
3022     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
3023     pushValueAndType(I.getOperand(0), InstID, Vals);
3024     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
3025     Vals.append(EVI->idx_begin(), EVI->idx_end());
3026     break;
3027   }
3028   case Instruction::InsertValue: {
3029     Code = bitc::FUNC_CODE_INST_INSERTVAL;
3030     pushValueAndType(I.getOperand(0), InstID, Vals);
3031     pushValueAndType(I.getOperand(1), InstID, Vals);
3032     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
3033     Vals.append(IVI->idx_begin(), IVI->idx_end());
3034     break;
3035   }
3036   case Instruction::Select: {
3037     Code = bitc::FUNC_CODE_INST_VSELECT;
3038     pushValueAndType(I.getOperand(1), InstID, Vals);
3039     pushValue(I.getOperand(2), InstID, Vals);
3040     pushValueAndType(I.getOperand(0), InstID, Vals);
3041     uint64_t Flags = getOptimizationFlags(&I);
3042     if (Flags != 0)
3043       Vals.push_back(Flags);
3044     break;
3045   }
3046   case Instruction::ExtractElement:
3047     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
3048     pushValueAndType(I.getOperand(0), InstID, Vals);
3049     pushValueAndType(I.getOperand(1), InstID, Vals);
3050     break;
3051   case Instruction::InsertElement:
3052     Code = bitc::FUNC_CODE_INST_INSERTELT;
3053     pushValueAndType(I.getOperand(0), InstID, Vals);
3054     pushValue(I.getOperand(1), InstID, Vals);
3055     pushValueAndType(I.getOperand(2), InstID, Vals);
3056     break;
3057   case Instruction::ShuffleVector:
3058     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
3059     pushValueAndType(I.getOperand(0), InstID, Vals);
3060     pushValue(I.getOperand(1), InstID, Vals);
3061     pushValue(cast<ShuffleVectorInst>(I).getShuffleMaskForBitcode(), InstID,
3062               Vals);
3063     break;
3064   case Instruction::ICmp:
3065   case Instruction::FCmp: {
3066     // compare returning Int1Ty or vector of Int1Ty
3067     Code = bitc::FUNC_CODE_INST_CMP2;
3068     pushValueAndType(I.getOperand(0), InstID, Vals);
3069     pushValue(I.getOperand(1), InstID, Vals);
3070     Vals.push_back(cast<CmpInst>(I).getPredicate());
3071     uint64_t Flags = getOptimizationFlags(&I);
3072     if (Flags != 0)
3073       Vals.push_back(Flags);
3074     break;
3075   }
3076 
3077   case Instruction::Ret:
3078     {
3079       Code = bitc::FUNC_CODE_INST_RET;
3080       unsigned NumOperands = I.getNumOperands();
3081       if (NumOperands == 0)
3082         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
3083       else if (NumOperands == 1) {
3084         if (!pushValueAndType(I.getOperand(0), InstID, Vals))
3085           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
3086       } else {
3087         for (const Value *Op : I.operands())
3088           pushValueAndType(Op, InstID, Vals);
3089       }
3090     }
3091     break;
3092   case Instruction::Br:
3093     {
3094       Code = bitc::FUNC_CODE_INST_BR;
3095       const BranchInst &II = cast<BranchInst>(I);
3096       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
3097       if (II.isConditional()) {
3098         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
3099         pushValue(II.getCondition(), InstID, Vals);
3100       }
3101     }
3102     break;
3103   case Instruction::Switch:
3104     {
3105       Code = bitc::FUNC_CODE_INST_SWITCH;
3106       const SwitchInst &SI = cast<SwitchInst>(I);
3107       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
3108       pushValue(SI.getCondition(), InstID, Vals);
3109       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
3110       for (auto Case : SI.cases()) {
3111         Vals.push_back(VE.getValueID(Case.getCaseValue()));
3112         Vals.push_back(VE.getValueID(Case.getCaseSuccessor()));
3113       }
3114     }
3115     break;
3116   case Instruction::IndirectBr:
3117     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
3118     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
3119     // Encode the address operand as relative, but not the basic blocks.
3120     pushValue(I.getOperand(0), InstID, Vals);
3121     for (const Value *Op : drop_begin(I.operands()))
3122       Vals.push_back(VE.getValueID(Op));
3123     break;
3124 
3125   case Instruction::Invoke: {
3126     const InvokeInst *II = cast<InvokeInst>(&I);
3127     const Value *Callee = II->getCalledOperand();
3128     FunctionType *FTy = II->getFunctionType();
3129 
3130     if (II->hasOperandBundles())
3131       writeOperandBundles(*II, InstID);
3132 
3133     Code = bitc::FUNC_CODE_INST_INVOKE;
3134 
3135     Vals.push_back(VE.getAttributeListID(II->getAttributes()));
3136     Vals.push_back(II->getCallingConv() | 1 << 13);
3137     Vals.push_back(VE.getValueID(II->getNormalDest()));
3138     Vals.push_back(VE.getValueID(II->getUnwindDest()));
3139     Vals.push_back(VE.getTypeID(FTy));
3140     pushValueAndType(Callee, InstID, Vals);
3141 
3142     // Emit value #'s for the fixed parameters.
3143     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
3144       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
3145 
3146     // Emit type/value pairs for varargs params.
3147     if (FTy->isVarArg()) {
3148       for (unsigned i = FTy->getNumParams(), e = II->arg_size(); i != e; ++i)
3149         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
3150     }
3151     break;
3152   }
3153   case Instruction::Resume:
3154     Code = bitc::FUNC_CODE_INST_RESUME;
3155     pushValueAndType(I.getOperand(0), InstID, Vals);
3156     break;
3157   case Instruction::CleanupRet: {
3158     Code = bitc::FUNC_CODE_INST_CLEANUPRET;
3159     const auto &CRI = cast<CleanupReturnInst>(I);
3160     pushValue(CRI.getCleanupPad(), InstID, Vals);
3161     if (CRI.hasUnwindDest())
3162       Vals.push_back(VE.getValueID(CRI.getUnwindDest()));
3163     break;
3164   }
3165   case Instruction::CatchRet: {
3166     Code = bitc::FUNC_CODE_INST_CATCHRET;
3167     const auto &CRI = cast<CatchReturnInst>(I);
3168     pushValue(CRI.getCatchPad(), InstID, Vals);
3169     Vals.push_back(VE.getValueID(CRI.getSuccessor()));
3170     break;
3171   }
3172   case Instruction::CleanupPad:
3173   case Instruction::CatchPad: {
3174     const auto &FuncletPad = cast<FuncletPadInst>(I);
3175     Code = isa<CatchPadInst>(FuncletPad) ? bitc::FUNC_CODE_INST_CATCHPAD
3176                                          : bitc::FUNC_CODE_INST_CLEANUPPAD;
3177     pushValue(FuncletPad.getParentPad(), InstID, Vals);
3178 
3179     unsigned NumArgOperands = FuncletPad.arg_size();
3180     Vals.push_back(NumArgOperands);
3181     for (unsigned Op = 0; Op != NumArgOperands; ++Op)
3182       pushValueAndType(FuncletPad.getArgOperand(Op), InstID, Vals);
3183     break;
3184   }
3185   case Instruction::CatchSwitch: {
3186     Code = bitc::FUNC_CODE_INST_CATCHSWITCH;
3187     const auto &CatchSwitch = cast<CatchSwitchInst>(I);
3188 
3189     pushValue(CatchSwitch.getParentPad(), InstID, Vals);
3190 
3191     unsigned NumHandlers = CatchSwitch.getNumHandlers();
3192     Vals.push_back(NumHandlers);
3193     for (const BasicBlock *CatchPadBB : CatchSwitch.handlers())
3194       Vals.push_back(VE.getValueID(CatchPadBB));
3195 
3196     if (CatchSwitch.hasUnwindDest())
3197       Vals.push_back(VE.getValueID(CatchSwitch.getUnwindDest()));
3198     break;
3199   }
3200   case Instruction::CallBr: {
3201     const CallBrInst *CBI = cast<CallBrInst>(&I);
3202     const Value *Callee = CBI->getCalledOperand();
3203     FunctionType *FTy = CBI->getFunctionType();
3204 
3205     if (CBI->hasOperandBundles())
3206       writeOperandBundles(*CBI, InstID);
3207 
3208     Code = bitc::FUNC_CODE_INST_CALLBR;
3209 
3210     Vals.push_back(VE.getAttributeListID(CBI->getAttributes()));
3211 
3212     Vals.push_back(CBI->getCallingConv() << bitc::CALL_CCONV |
3213                    1 << bitc::CALL_EXPLICIT_TYPE);
3214 
3215     Vals.push_back(VE.getValueID(CBI->getDefaultDest()));
3216     Vals.push_back(CBI->getNumIndirectDests());
3217     for (unsigned i = 0, e = CBI->getNumIndirectDests(); i != e; ++i)
3218       Vals.push_back(VE.getValueID(CBI->getIndirectDest(i)));
3219 
3220     Vals.push_back(VE.getTypeID(FTy));
3221     pushValueAndType(Callee, InstID, Vals);
3222 
3223     // Emit value #'s for the fixed parameters.
3224     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
3225       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
3226 
3227     // Emit type/value pairs for varargs params.
3228     if (FTy->isVarArg()) {
3229       for (unsigned i = FTy->getNumParams(), e = CBI->arg_size(); i != e; ++i)
3230         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
3231     }
3232     break;
3233   }
3234   case Instruction::Unreachable:
3235     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
3236     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
3237     break;
3238 
3239   case Instruction::PHI: {
3240     const PHINode &PN = cast<PHINode>(I);
3241     Code = bitc::FUNC_CODE_INST_PHI;
3242     // With the newer instruction encoding, forward references could give
3243     // negative valued IDs.  This is most common for PHIs, so we use
3244     // signed VBRs.
3245     SmallVector<uint64_t, 128> Vals64;
3246     Vals64.push_back(VE.getTypeID(PN.getType()));
3247     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
3248       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64);
3249       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
3250     }
3251 
3252     uint64_t Flags = getOptimizationFlags(&I);
3253     if (Flags != 0)
3254       Vals64.push_back(Flags);
3255 
3256     // Emit a Vals64 vector and exit.
3257     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
3258     Vals64.clear();
3259     return;
3260   }
3261 
3262   case Instruction::LandingPad: {
3263     const LandingPadInst &LP = cast<LandingPadInst>(I);
3264     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
3265     Vals.push_back(VE.getTypeID(LP.getType()));
3266     Vals.push_back(LP.isCleanup());
3267     Vals.push_back(LP.getNumClauses());
3268     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
3269       if (LP.isCatch(I))
3270         Vals.push_back(LandingPadInst::Catch);
3271       else
3272         Vals.push_back(LandingPadInst::Filter);
3273       pushValueAndType(LP.getClause(I), InstID, Vals);
3274     }
3275     break;
3276   }
3277 
3278   case Instruction::Alloca: {
3279     Code = bitc::FUNC_CODE_INST_ALLOCA;
3280     const AllocaInst &AI = cast<AllocaInst>(I);
3281     Vals.push_back(VE.getTypeID(AI.getAllocatedType()));
3282     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
3283     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
3284     using APV = AllocaPackedValues;
3285     unsigned Record = 0;
3286     unsigned EncodedAlign = getEncodedAlign(AI.getAlign());
3287     Bitfield::set<APV::AlignLower>(
3288         Record, EncodedAlign & ((1 << APV::AlignLower::Bits) - 1));
3289     Bitfield::set<APV::AlignUpper>(Record,
3290                                    EncodedAlign >> APV::AlignLower::Bits);
3291     Bitfield::set<APV::UsedWithInAlloca>(Record, AI.isUsedWithInAlloca());
3292     Bitfield::set<APV::ExplicitType>(Record, true);
3293     Bitfield::set<APV::SwiftError>(Record, AI.isSwiftError());
3294     Vals.push_back(Record);
3295 
3296     unsigned AS = AI.getAddressSpace();
3297     if (AS != M.getDataLayout().getAllocaAddrSpace())
3298       Vals.push_back(AS);
3299     break;
3300   }
3301 
3302   case Instruction::Load:
3303     if (cast<LoadInst>(I).isAtomic()) {
3304       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
3305       pushValueAndType(I.getOperand(0), InstID, Vals);
3306     } else {
3307       Code = bitc::FUNC_CODE_INST_LOAD;
3308       if (!pushValueAndType(I.getOperand(0), InstID, Vals)) // ptr
3309         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
3310     }
3311     Vals.push_back(VE.getTypeID(I.getType()));
3312     Vals.push_back(getEncodedAlign(cast<LoadInst>(I).getAlign()));
3313     Vals.push_back(cast<LoadInst>(I).isVolatile());
3314     if (cast<LoadInst>(I).isAtomic()) {
3315       Vals.push_back(getEncodedOrdering(cast<LoadInst>(I).getOrdering()));
3316       Vals.push_back(getEncodedSyncScopeID(cast<LoadInst>(I).getSyncScopeID()));
3317     }
3318     break;
3319   case Instruction::Store:
3320     if (cast<StoreInst>(I).isAtomic())
3321       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
3322     else
3323       Code = bitc::FUNC_CODE_INST_STORE;
3324     pushValueAndType(I.getOperand(1), InstID, Vals); // ptrty + ptr
3325     pushValueAndType(I.getOperand(0), InstID, Vals); // valty + val
3326     Vals.push_back(getEncodedAlign(cast<StoreInst>(I).getAlign()));
3327     Vals.push_back(cast<StoreInst>(I).isVolatile());
3328     if (cast<StoreInst>(I).isAtomic()) {
3329       Vals.push_back(getEncodedOrdering(cast<StoreInst>(I).getOrdering()));
3330       Vals.push_back(
3331           getEncodedSyncScopeID(cast<StoreInst>(I).getSyncScopeID()));
3332     }
3333     break;
3334   case Instruction::AtomicCmpXchg:
3335     Code = bitc::FUNC_CODE_INST_CMPXCHG;
3336     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
3337     pushValueAndType(I.getOperand(1), InstID, Vals); // cmp.
3338     pushValue(I.getOperand(2), InstID, Vals);        // newval.
3339     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
3340     Vals.push_back(
3341         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
3342     Vals.push_back(
3343         getEncodedSyncScopeID(cast<AtomicCmpXchgInst>(I).getSyncScopeID()));
3344     Vals.push_back(
3345         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
3346     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
3347     Vals.push_back(getEncodedAlign(cast<AtomicCmpXchgInst>(I).getAlign()));
3348     break;
3349   case Instruction::AtomicRMW:
3350     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
3351     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
3352     pushValueAndType(I.getOperand(1), InstID, Vals); // valty + val
3353     Vals.push_back(
3354         getEncodedRMWOperation(cast<AtomicRMWInst>(I).getOperation()));
3355     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
3356     Vals.push_back(getEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
3357     Vals.push_back(
3358         getEncodedSyncScopeID(cast<AtomicRMWInst>(I).getSyncScopeID()));
3359     Vals.push_back(getEncodedAlign(cast<AtomicRMWInst>(I).getAlign()));
3360     break;
3361   case Instruction::Fence:
3362     Code = bitc::FUNC_CODE_INST_FENCE;
3363     Vals.push_back(getEncodedOrdering(cast<FenceInst>(I).getOrdering()));
3364     Vals.push_back(getEncodedSyncScopeID(cast<FenceInst>(I).getSyncScopeID()));
3365     break;
3366   case Instruction::Call: {
3367     const CallInst &CI = cast<CallInst>(I);
3368     FunctionType *FTy = CI.getFunctionType();
3369 
3370     if (CI.hasOperandBundles())
3371       writeOperandBundles(CI, InstID);
3372 
3373     Code = bitc::FUNC_CODE_INST_CALL;
3374 
3375     Vals.push_back(VE.getAttributeListID(CI.getAttributes()));
3376 
3377     unsigned Flags = getOptimizationFlags(&I);
3378     Vals.push_back(CI.getCallingConv() << bitc::CALL_CCONV |
3379                    unsigned(CI.isTailCall()) << bitc::CALL_TAIL |
3380                    unsigned(CI.isMustTailCall()) << bitc::CALL_MUSTTAIL |
3381                    1 << bitc::CALL_EXPLICIT_TYPE |
3382                    unsigned(CI.isNoTailCall()) << bitc::CALL_NOTAIL |
3383                    unsigned(Flags != 0) << bitc::CALL_FMF);
3384     if (Flags != 0)
3385       Vals.push_back(Flags);
3386 
3387     Vals.push_back(VE.getTypeID(FTy));
3388     pushValueAndType(CI.getCalledOperand(), InstID, Vals); // Callee
3389 
3390     // Emit value #'s for the fixed parameters.
3391     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
3392       // Check for labels (can happen with asm labels).
3393       if (FTy->getParamType(i)->isLabelTy())
3394         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
3395       else
3396         pushValue(CI.getArgOperand(i), InstID, Vals); // fixed param.
3397     }
3398 
3399     // Emit type/value pairs for varargs params.
3400     if (FTy->isVarArg()) {
3401       for (unsigned i = FTy->getNumParams(), e = CI.arg_size(); i != e; ++i)
3402         pushValueAndType(CI.getArgOperand(i), InstID, Vals); // varargs
3403     }
3404     break;
3405   }
3406   case Instruction::VAArg:
3407     Code = bitc::FUNC_CODE_INST_VAARG;
3408     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
3409     pushValue(I.getOperand(0), InstID, Vals);                   // valist.
3410     Vals.push_back(VE.getTypeID(I.getType())); // restype.
3411     break;
3412   case Instruction::Freeze:
3413     Code = bitc::FUNC_CODE_INST_FREEZE;
3414     pushValueAndType(I.getOperand(0), InstID, Vals);
3415     break;
3416   }
3417 
3418   Stream.EmitRecord(Code, Vals, AbbrevToUse);
3419   Vals.clear();
3420 }
3421 
3422 /// Write a GlobalValue VST to the module. The purpose of this data structure is
3423 /// to allow clients to efficiently find the function body.
3424 void ModuleBitcodeWriter::writeGlobalValueSymbolTable(
3425   DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3426   // Get the offset of the VST we are writing, and backpatch it into
3427   // the VST forward declaration record.
3428   uint64_t VSTOffset = Stream.GetCurrentBitNo();
3429   // The BitcodeStartBit was the stream offset of the identification block.
3430   VSTOffset -= bitcodeStartBit();
3431   assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
3432   // Note that we add 1 here because the offset is relative to one word
3433   // before the start of the identification block, which was historically
3434   // always the start of the regular bitcode header.
3435   Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32 + 1);
3436 
3437   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3438 
3439   auto Abbv = std::make_shared<BitCodeAbbrev>();
3440   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
3441   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
3442   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
3443   unsigned FnEntryAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3444 
3445   for (const Function &F : M) {
3446     uint64_t Record[2];
3447 
3448     if (F.isDeclaration())
3449       continue;
3450 
3451     Record[0] = VE.getValueID(&F);
3452 
3453     // Save the word offset of the function (from the start of the
3454     // actual bitcode written to the stream).
3455     uint64_t BitcodeIndex = FunctionToBitcodeIndex[&F] - bitcodeStartBit();
3456     assert((BitcodeIndex & 31) == 0 && "function block not 32-bit aligned");
3457     // Note that we add 1 here because the offset is relative to one word
3458     // before the start of the identification block, which was historically
3459     // always the start of the regular bitcode header.
3460     Record[1] = BitcodeIndex / 32 + 1;
3461 
3462     Stream.EmitRecord(bitc::VST_CODE_FNENTRY, Record, FnEntryAbbrev);
3463   }
3464 
3465   Stream.ExitBlock();
3466 }
3467 
3468 /// Emit names for arguments, instructions and basic blocks in a function.
3469 void ModuleBitcodeWriter::writeFunctionLevelValueSymbolTable(
3470     const ValueSymbolTable &VST) {
3471   if (VST.empty())
3472     return;
3473 
3474   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3475 
3476   // FIXME: Set up the abbrev, we know how many values there are!
3477   // FIXME: We know if the type names can use 7-bit ascii.
3478   SmallVector<uint64_t, 64> NameVals;
3479 
3480   for (const ValueName &Name : VST) {
3481     // Figure out the encoding to use for the name.
3482     StringEncoding Bits = getStringEncoding(Name.getKey());
3483 
3484     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
3485     NameVals.push_back(VE.getValueID(Name.getValue()));
3486 
3487     // VST_CODE_ENTRY:   [valueid, namechar x N]
3488     // VST_CODE_BBENTRY: [bbid, namechar x N]
3489     unsigned Code;
3490     if (isa<BasicBlock>(Name.getValue())) {
3491       Code = bitc::VST_CODE_BBENTRY;
3492       if (Bits == SE_Char6)
3493         AbbrevToUse = VST_BBENTRY_6_ABBREV;
3494     } else {
3495       Code = bitc::VST_CODE_ENTRY;
3496       if (Bits == SE_Char6)
3497         AbbrevToUse = VST_ENTRY_6_ABBREV;
3498       else if (Bits == SE_Fixed7)
3499         AbbrevToUse = VST_ENTRY_7_ABBREV;
3500     }
3501 
3502     for (const auto P : Name.getKey())
3503       NameVals.push_back((unsigned char)P);
3504 
3505     // Emit the finished record.
3506     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
3507     NameVals.clear();
3508   }
3509 
3510   Stream.ExitBlock();
3511 }
3512 
3513 void ModuleBitcodeWriter::writeUseList(UseListOrder &&Order) {
3514   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
3515   unsigned Code;
3516   if (isa<BasicBlock>(Order.V))
3517     Code = bitc::USELIST_CODE_BB;
3518   else
3519     Code = bitc::USELIST_CODE_DEFAULT;
3520 
3521   SmallVector<uint64_t, 64> Record(Order.Shuffle.begin(), Order.Shuffle.end());
3522   Record.push_back(VE.getValueID(Order.V));
3523   Stream.EmitRecord(Code, Record);
3524 }
3525 
3526 void ModuleBitcodeWriter::writeUseListBlock(const Function *F) {
3527   assert(VE.shouldPreserveUseListOrder() &&
3528          "Expected to be preserving use-list order");
3529 
3530   auto hasMore = [&]() {
3531     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
3532   };
3533   if (!hasMore())
3534     // Nothing to do.
3535     return;
3536 
3537   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
3538   while (hasMore()) {
3539     writeUseList(std::move(VE.UseListOrders.back()));
3540     VE.UseListOrders.pop_back();
3541   }
3542   Stream.ExitBlock();
3543 }
3544 
3545 /// Emit a function body to the module stream.
3546 void ModuleBitcodeWriter::writeFunction(
3547     const Function &F,
3548     DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3549   // Save the bitcode index of the start of this function block for recording
3550   // in the VST.
3551   FunctionToBitcodeIndex[&F] = Stream.GetCurrentBitNo();
3552 
3553   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
3554   VE.incorporateFunction(F);
3555 
3556   SmallVector<unsigned, 64> Vals;
3557 
3558   // Emit the number of basic blocks, so the reader can create them ahead of
3559   // time.
3560   Vals.push_back(VE.getBasicBlocks().size());
3561   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
3562   Vals.clear();
3563 
3564   // If there are function-local constants, emit them now.
3565   unsigned CstStart, CstEnd;
3566   VE.getFunctionConstantRange(CstStart, CstEnd);
3567   writeConstants(CstStart, CstEnd, false);
3568 
3569   // If there is function-local metadata, emit it now.
3570   writeFunctionMetadata(F);
3571 
3572   // Keep a running idea of what the instruction ID is.
3573   unsigned InstID = CstEnd;
3574 
3575   bool NeedsMetadataAttachment = F.hasMetadata();
3576 
3577   DILocation *LastDL = nullptr;
3578   SmallSetVector<Function *, 4> BlockAddressUsers;
3579 
3580   // Finally, emit all the instructions, in order.
3581   for (const BasicBlock &BB : F) {
3582     for (const Instruction &I : BB) {
3583       writeInstruction(I, InstID, Vals);
3584 
3585       if (!I.getType()->isVoidTy())
3586         ++InstID;
3587 
3588       // If the instruction has metadata, write a metadata attachment later.
3589       NeedsMetadataAttachment |= I.hasMetadataOtherThanDebugLoc();
3590 
3591       // If the instruction has a debug location, emit it.
3592       if (DILocation *DL = I.getDebugLoc()) {
3593         if (DL == LastDL) {
3594           // Just repeat the same debug loc as last time.
3595           Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
3596         } else {
3597           Vals.push_back(DL->getLine());
3598           Vals.push_back(DL->getColumn());
3599           Vals.push_back(VE.getMetadataOrNullID(DL->getScope()));
3600           Vals.push_back(VE.getMetadataOrNullID(DL->getInlinedAt()));
3601           Vals.push_back(DL->isImplicitCode());
3602           Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
3603           Vals.clear();
3604           LastDL = DL;
3605         }
3606       }
3607 
3608       // If the instruction has DbgRecords attached to it, emit them. Note that
3609       // they come after the instruction so that it's easy to attach them again
3610       // when reading the bitcode, even though conceptually the debug locations
3611       // start "before" the instruction.
3612       if (I.hasDbgRecords() && WriteNewDbgInfoFormatToBitcode) {
3613         /// Try to push the value only (unwrapped), otherwise push the
3614         /// metadata wrapped value. Returns true if the value was pushed
3615         /// without the ValueAsMetadata wrapper.
3616         auto PushValueOrMetadata = [&Vals, InstID,
3617                                     this](Metadata *RawLocation) {
3618           assert(RawLocation &&
3619                  "RawLocation unexpectedly null in DbgVariableRecord");
3620           if (ValueAsMetadata *VAM = dyn_cast<ValueAsMetadata>(RawLocation)) {
3621             SmallVector<unsigned, 2> ValAndType;
3622             // If the value is a fwd-ref the type is also pushed. We don't
3623             // want the type, so fwd-refs are kept wrapped (pushValueAndType
3624             // returns false if the value is pushed without type).
3625             if (!pushValueAndType(VAM->getValue(), InstID, ValAndType)) {
3626               Vals.push_back(ValAndType[0]);
3627               return true;
3628             }
3629           }
3630           // The metadata is a DIArgList, or ValueAsMetadata wrapping a
3631           // fwd-ref. Push the metadata ID.
3632           Vals.push_back(VE.getMetadataID(RawLocation));
3633           return false;
3634         };
3635 
3636         // Write out non-instruction debug information attached to this
3637         // instruction. Write it after the instruction so that it's easy to
3638         // re-attach to the instruction reading the records in.
3639         for (DbgRecord &DR : I.DebugMarker->getDbgRecordRange()) {
3640           if (DbgLabelRecord *DLR = dyn_cast<DbgLabelRecord>(&DR)) {
3641             Vals.push_back(VE.getMetadataID(&*DLR->getDebugLoc()));
3642             Vals.push_back(VE.getMetadataID(DLR->getLabel()));
3643             Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_RECORD_LABEL, Vals);
3644             Vals.clear();
3645             continue;
3646           }
3647 
3648           // First 3 fields are common to all kinds:
3649           //   DILocation, DILocalVariable, DIExpression
3650           // dbg_value (FUNC_CODE_DEBUG_RECORD_VALUE)
3651           //   ..., LocationMetadata
3652           // dbg_value (FUNC_CODE_DEBUG_RECORD_VALUE_SIMPLE - abbrev'd)
3653           //   ..., Value
3654           // dbg_declare (FUNC_CODE_DEBUG_RECORD_DECLARE)
3655           //   ..., LocationMetadata
3656           // dbg_assign (FUNC_CODE_DEBUG_RECORD_ASSIGN)
3657           //   ..., LocationMetadata, DIAssignID, DIExpression, LocationMetadata
3658           DbgVariableRecord &DVR = cast<DbgVariableRecord>(DR);
3659           Vals.push_back(VE.getMetadataID(&*DVR.getDebugLoc()));
3660           Vals.push_back(VE.getMetadataID(DVR.getVariable()));
3661           Vals.push_back(VE.getMetadataID(DVR.getExpression()));
3662           if (DVR.isDbgValue()) {
3663             if (PushValueOrMetadata(DVR.getRawLocation()))
3664               Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_RECORD_VALUE_SIMPLE, Vals,
3665                                 FUNCTION_DEBUG_RECORD_VALUE_ABBREV);
3666             else
3667               Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_RECORD_VALUE, Vals);
3668           } else if (DVR.isDbgDeclare()) {
3669             Vals.push_back(VE.getMetadataID(DVR.getRawLocation()));
3670             Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_RECORD_DECLARE, Vals);
3671           } else {
3672             assert(DVR.isDbgAssign() && "Unexpected DbgRecord kind");
3673             Vals.push_back(VE.getMetadataID(DVR.getRawLocation()));
3674             Vals.push_back(VE.getMetadataID(DVR.getAssignID()));
3675             Vals.push_back(VE.getMetadataID(DVR.getAddressExpression()));
3676             Vals.push_back(VE.getMetadataID(DVR.getRawAddress()));
3677             Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_RECORD_ASSIGN, Vals);
3678           }
3679           Vals.clear();
3680         }
3681       }
3682     }
3683 
3684     if (BlockAddress *BA = BlockAddress::lookup(&BB)) {
3685       SmallVector<Value *> Worklist{BA};
3686       SmallPtrSet<Value *, 8> Visited{BA};
3687       while (!Worklist.empty()) {
3688         Value *V = Worklist.pop_back_val();
3689         for (User *U : V->users()) {
3690           if (auto *I = dyn_cast<Instruction>(U)) {
3691             Function *P = I->getFunction();
3692             if (P != &F)
3693               BlockAddressUsers.insert(P);
3694           } else if (isa<Constant>(U) && !isa<GlobalValue>(U) &&
3695                      Visited.insert(U).second)
3696             Worklist.push_back(U);
3697         }
3698       }
3699     }
3700   }
3701 
3702   if (!BlockAddressUsers.empty()) {
3703     Vals.resize(BlockAddressUsers.size());
3704     for (auto I : llvm::enumerate(BlockAddressUsers))
3705       Vals[I.index()] = VE.getValueID(I.value());
3706     Stream.EmitRecord(bitc::FUNC_CODE_BLOCKADDR_USERS, Vals);
3707     Vals.clear();
3708   }
3709 
3710   // Emit names for all the instructions etc.
3711   if (auto *Symtab = F.getValueSymbolTable())
3712     writeFunctionLevelValueSymbolTable(*Symtab);
3713 
3714   if (NeedsMetadataAttachment)
3715     writeFunctionMetadataAttachment(F);
3716   if (VE.shouldPreserveUseListOrder())
3717     writeUseListBlock(&F);
3718   VE.purgeFunction();
3719   Stream.ExitBlock();
3720 }
3721 
3722 // Emit blockinfo, which defines the standard abbreviations etc.
3723 void ModuleBitcodeWriter::writeBlockInfo() {
3724   // We only want to emit block info records for blocks that have multiple
3725   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
3726   // Other blocks can define their abbrevs inline.
3727   Stream.EnterBlockInfoBlock();
3728 
3729   { // 8-bit fixed-width VST_CODE_ENTRY/VST_CODE_BBENTRY strings.
3730     auto Abbv = std::make_shared<BitCodeAbbrev>();
3731     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
3732     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3733     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3734     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3735     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3736         VST_ENTRY_8_ABBREV)
3737       llvm_unreachable("Unexpected abbrev ordering!");
3738   }
3739 
3740   { // 7-bit fixed width VST_CODE_ENTRY strings.
3741     auto Abbv = std::make_shared<BitCodeAbbrev>();
3742     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3743     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3744     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3745     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3746     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3747         VST_ENTRY_7_ABBREV)
3748       llvm_unreachable("Unexpected abbrev ordering!");
3749   }
3750   { // 6-bit char6 VST_CODE_ENTRY strings.
3751     auto Abbv = std::make_shared<BitCodeAbbrev>();
3752     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3753     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3754     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3755     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3756     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3757         VST_ENTRY_6_ABBREV)
3758       llvm_unreachable("Unexpected abbrev ordering!");
3759   }
3760   { // 6-bit char6 VST_CODE_BBENTRY strings.
3761     auto Abbv = std::make_shared<BitCodeAbbrev>();
3762     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
3763     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3764     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3765     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3766     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3767         VST_BBENTRY_6_ABBREV)
3768       llvm_unreachable("Unexpected abbrev ordering!");
3769   }
3770 
3771   { // SETTYPE abbrev for CONSTANTS_BLOCK.
3772     auto Abbv = std::make_shared<BitCodeAbbrev>();
3773     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
3774     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
3775                               VE.computeBitsRequiredForTypeIndices()));
3776     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3777         CONSTANTS_SETTYPE_ABBREV)
3778       llvm_unreachable("Unexpected abbrev ordering!");
3779   }
3780 
3781   { // INTEGER abbrev for CONSTANTS_BLOCK.
3782     auto Abbv = std::make_shared<BitCodeAbbrev>();
3783     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
3784     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3785     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3786         CONSTANTS_INTEGER_ABBREV)
3787       llvm_unreachable("Unexpected abbrev ordering!");
3788   }
3789 
3790   { // CE_CAST abbrev for CONSTANTS_BLOCK.
3791     auto Abbv = std::make_shared<BitCodeAbbrev>();
3792     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
3793     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
3794     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
3795                               VE.computeBitsRequiredForTypeIndices()));
3796     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
3797 
3798     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3799         CONSTANTS_CE_CAST_Abbrev)
3800       llvm_unreachable("Unexpected abbrev ordering!");
3801   }
3802   { // NULL abbrev for CONSTANTS_BLOCK.
3803     auto Abbv = std::make_shared<BitCodeAbbrev>();
3804     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
3805     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3806         CONSTANTS_NULL_Abbrev)
3807       llvm_unreachable("Unexpected abbrev ordering!");
3808   }
3809 
3810   // FIXME: This should only use space for first class types!
3811 
3812   { // INST_LOAD abbrev for FUNCTION_BLOCK.
3813     auto Abbv = std::make_shared<BitCodeAbbrev>();
3814     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
3815     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
3816     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
3817                               VE.computeBitsRequiredForTypeIndices()));
3818     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
3819     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
3820     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3821         FUNCTION_INST_LOAD_ABBREV)
3822       llvm_unreachable("Unexpected abbrev ordering!");
3823   }
3824   { // INST_UNOP abbrev for FUNCTION_BLOCK.
3825     auto Abbv = std::make_shared<BitCodeAbbrev>();
3826     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3827     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3828     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3829     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3830         FUNCTION_INST_UNOP_ABBREV)
3831       llvm_unreachable("Unexpected abbrev ordering!");
3832   }
3833   { // INST_UNOP_FLAGS abbrev for FUNCTION_BLOCK.
3834     auto Abbv = std::make_shared<BitCodeAbbrev>();
3835     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3836     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3837     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3838     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3839     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3840         FUNCTION_INST_UNOP_FLAGS_ABBREV)
3841       llvm_unreachable("Unexpected abbrev ordering!");
3842   }
3843   { // INST_BINOP abbrev for FUNCTION_BLOCK.
3844     auto Abbv = std::make_shared<BitCodeAbbrev>();
3845     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3846     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3847     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3848     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3849     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3850         FUNCTION_INST_BINOP_ABBREV)
3851       llvm_unreachable("Unexpected abbrev ordering!");
3852   }
3853   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
3854     auto Abbv = std::make_shared<BitCodeAbbrev>();
3855     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3856     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3857     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3858     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3859     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3860     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3861         FUNCTION_INST_BINOP_FLAGS_ABBREV)
3862       llvm_unreachable("Unexpected abbrev ordering!");
3863   }
3864   { // INST_CAST abbrev for FUNCTION_BLOCK.
3865     auto Abbv = std::make_shared<BitCodeAbbrev>();
3866     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
3867     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
3868     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
3869                               VE.computeBitsRequiredForTypeIndices()));
3870     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
3871     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3872         FUNCTION_INST_CAST_ABBREV)
3873       llvm_unreachable("Unexpected abbrev ordering!");
3874   }
3875   { // INST_CAST_FLAGS abbrev for FUNCTION_BLOCK.
3876     auto Abbv = std::make_shared<BitCodeAbbrev>();
3877     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
3878     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // OpVal
3879     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
3880                               VE.computeBitsRequiredForTypeIndices()));
3881     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3882     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3883     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3884         FUNCTION_INST_CAST_FLAGS_ABBREV)
3885       llvm_unreachable("Unexpected abbrev ordering!");
3886   }
3887 
3888   { // INST_RET abbrev for FUNCTION_BLOCK.
3889     auto Abbv = std::make_shared<BitCodeAbbrev>();
3890     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3891     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3892         FUNCTION_INST_RET_VOID_ABBREV)
3893       llvm_unreachable("Unexpected abbrev ordering!");
3894   }
3895   { // INST_RET abbrev for FUNCTION_BLOCK.
3896     auto Abbv = std::make_shared<BitCodeAbbrev>();
3897     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3898     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
3899     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3900         FUNCTION_INST_RET_VAL_ABBREV)
3901       llvm_unreachable("Unexpected abbrev ordering!");
3902   }
3903   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
3904     auto Abbv = std::make_shared<BitCodeAbbrev>();
3905     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
3906     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3907         FUNCTION_INST_UNREACHABLE_ABBREV)
3908       llvm_unreachable("Unexpected abbrev ordering!");
3909   }
3910   {
3911     auto Abbv = std::make_shared<BitCodeAbbrev>();
3912     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_GEP));
3913     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
3914     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, // dest ty
3915                               Log2_32_Ceil(VE.getTypes().size() + 1)));
3916     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3917     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
3918     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3919         FUNCTION_INST_GEP_ABBREV)
3920       llvm_unreachable("Unexpected abbrev ordering!");
3921   }
3922   {
3923     auto Abbv = std::make_shared<BitCodeAbbrev>();
3924     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_DEBUG_RECORD_VALUE_SIMPLE));
3925     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 7)); // dbgloc
3926     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 7)); // var
3927     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 7)); // expr
3928     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // val
3929     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3930         FUNCTION_DEBUG_RECORD_VALUE_ABBREV)
3931       llvm_unreachable("Unexpected abbrev ordering! 1");
3932   }
3933   Stream.ExitBlock();
3934 }
3935 
3936 /// Write the module path strings, currently only used when generating
3937 /// a combined index file.
3938 void IndexBitcodeWriter::writeModStrings() {
3939   Stream.EnterSubblock(bitc::MODULE_STRTAB_BLOCK_ID, 3);
3940 
3941   // TODO: See which abbrev sizes we actually need to emit
3942 
3943   // 8-bit fixed-width MST_ENTRY strings.
3944   auto Abbv = std::make_shared<BitCodeAbbrev>();
3945   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3946   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3947   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3948   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3949   unsigned Abbrev8Bit = Stream.EmitAbbrev(std::move(Abbv));
3950 
3951   // 7-bit fixed width MST_ENTRY strings.
3952   Abbv = std::make_shared<BitCodeAbbrev>();
3953   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3954   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3955   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3956   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3957   unsigned Abbrev7Bit = Stream.EmitAbbrev(std::move(Abbv));
3958 
3959   // 6-bit char6 MST_ENTRY strings.
3960   Abbv = std::make_shared<BitCodeAbbrev>();
3961   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3962   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3963   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3964   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3965   unsigned Abbrev6Bit = Stream.EmitAbbrev(std::move(Abbv));
3966 
3967   // Module Hash, 160 bits SHA1. Optionally, emitted after each MST_CODE_ENTRY.
3968   Abbv = std::make_shared<BitCodeAbbrev>();
3969   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_HASH));
3970   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3971   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3972   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3973   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3974   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3975   unsigned AbbrevHash = Stream.EmitAbbrev(std::move(Abbv));
3976 
3977   SmallVector<unsigned, 64> Vals;
3978   forEachModule([&](const StringMapEntry<ModuleHash> &MPSE) {
3979     StringRef Key = MPSE.getKey();
3980     const auto &Hash = MPSE.getValue();
3981     StringEncoding Bits = getStringEncoding(Key);
3982     unsigned AbbrevToUse = Abbrev8Bit;
3983     if (Bits == SE_Char6)
3984       AbbrevToUse = Abbrev6Bit;
3985     else if (Bits == SE_Fixed7)
3986       AbbrevToUse = Abbrev7Bit;
3987 
3988     auto ModuleId = ModuleIdMap.size();
3989     ModuleIdMap[Key] = ModuleId;
3990     Vals.push_back(ModuleId);
3991     Vals.append(Key.begin(), Key.end());
3992 
3993     // Emit the finished record.
3994     Stream.EmitRecord(bitc::MST_CODE_ENTRY, Vals, AbbrevToUse);
3995 
3996     // Emit an optional hash for the module now
3997     if (llvm::any_of(Hash, [](uint32_t H) { return H; })) {
3998       Vals.assign(Hash.begin(), Hash.end());
3999       // Emit the hash record.
4000       Stream.EmitRecord(bitc::MST_CODE_HASH, Vals, AbbrevHash);
4001     }
4002 
4003     Vals.clear();
4004   });
4005   Stream.ExitBlock();
4006 }
4007 
4008 /// Write the function type metadata related records that need to appear before
4009 /// a function summary entry (whether per-module or combined).
4010 template <typename Fn>
4011 static void writeFunctionTypeMetadataRecords(BitstreamWriter &Stream,
4012                                              FunctionSummary *FS,
4013                                              Fn GetValueID) {
4014   if (!FS->type_tests().empty())
4015     Stream.EmitRecord(bitc::FS_TYPE_TESTS, FS->type_tests());
4016 
4017   SmallVector<uint64_t, 64> Record;
4018 
4019   auto WriteVFuncIdVec = [&](uint64_t Ty,
4020                              ArrayRef<FunctionSummary::VFuncId> VFs) {
4021     if (VFs.empty())
4022       return;
4023     Record.clear();
4024     for (auto &VF : VFs) {
4025       Record.push_back(VF.GUID);
4026       Record.push_back(VF.Offset);
4027     }
4028     Stream.EmitRecord(Ty, Record);
4029   };
4030 
4031   WriteVFuncIdVec(bitc::FS_TYPE_TEST_ASSUME_VCALLS,
4032                   FS->type_test_assume_vcalls());
4033   WriteVFuncIdVec(bitc::FS_TYPE_CHECKED_LOAD_VCALLS,
4034                   FS->type_checked_load_vcalls());
4035 
4036   auto WriteConstVCallVec = [&](uint64_t Ty,
4037                                 ArrayRef<FunctionSummary::ConstVCall> VCs) {
4038     for (auto &VC : VCs) {
4039       Record.clear();
4040       Record.push_back(VC.VFunc.GUID);
4041       Record.push_back(VC.VFunc.Offset);
4042       llvm::append_range(Record, VC.Args);
4043       Stream.EmitRecord(Ty, Record);
4044     }
4045   };
4046 
4047   WriteConstVCallVec(bitc::FS_TYPE_TEST_ASSUME_CONST_VCALL,
4048                      FS->type_test_assume_const_vcalls());
4049   WriteConstVCallVec(bitc::FS_TYPE_CHECKED_LOAD_CONST_VCALL,
4050                      FS->type_checked_load_const_vcalls());
4051 
4052   auto WriteRange = [&](ConstantRange Range) {
4053     Range = Range.sextOrTrunc(FunctionSummary::ParamAccess::RangeWidth);
4054     assert(Range.getLower().getNumWords() == 1);
4055     assert(Range.getUpper().getNumWords() == 1);
4056     emitSignedInt64(Record, *Range.getLower().getRawData());
4057     emitSignedInt64(Record, *Range.getUpper().getRawData());
4058   };
4059 
4060   if (!FS->paramAccesses().empty()) {
4061     Record.clear();
4062     for (auto &Arg : FS->paramAccesses()) {
4063       size_t UndoSize = Record.size();
4064       Record.push_back(Arg.ParamNo);
4065       WriteRange(Arg.Use);
4066       Record.push_back(Arg.Calls.size());
4067       for (auto &Call : Arg.Calls) {
4068         Record.push_back(Call.ParamNo);
4069         std::optional<unsigned> ValueID = GetValueID(Call.Callee);
4070         if (!ValueID) {
4071           // If ValueID is unknown we can't drop just this call, we must drop
4072           // entire parameter.
4073           Record.resize(UndoSize);
4074           break;
4075         }
4076         Record.push_back(*ValueID);
4077         WriteRange(Call.Offsets);
4078       }
4079     }
4080     if (!Record.empty())
4081       Stream.EmitRecord(bitc::FS_PARAM_ACCESS, Record);
4082   }
4083 }
4084 
4085 /// Collect type IDs from type tests used by function.
4086 static void
4087 getReferencedTypeIds(FunctionSummary *FS,
4088                      std::set<GlobalValue::GUID> &ReferencedTypeIds) {
4089   if (!FS->type_tests().empty())
4090     for (auto &TT : FS->type_tests())
4091       ReferencedTypeIds.insert(TT);
4092 
4093   auto GetReferencedTypesFromVFuncIdVec =
4094       [&](ArrayRef<FunctionSummary::VFuncId> VFs) {
4095         for (auto &VF : VFs)
4096           ReferencedTypeIds.insert(VF.GUID);
4097       };
4098 
4099   GetReferencedTypesFromVFuncIdVec(FS->type_test_assume_vcalls());
4100   GetReferencedTypesFromVFuncIdVec(FS->type_checked_load_vcalls());
4101 
4102   auto GetReferencedTypesFromConstVCallVec =
4103       [&](ArrayRef<FunctionSummary::ConstVCall> VCs) {
4104         for (auto &VC : VCs)
4105           ReferencedTypeIds.insert(VC.VFunc.GUID);
4106       };
4107 
4108   GetReferencedTypesFromConstVCallVec(FS->type_test_assume_const_vcalls());
4109   GetReferencedTypesFromConstVCallVec(FS->type_checked_load_const_vcalls());
4110 }
4111 
4112 static void writeWholeProgramDevirtResolutionByArg(
4113     SmallVector<uint64_t, 64> &NameVals, const std::vector<uint64_t> &args,
4114     const WholeProgramDevirtResolution::ByArg &ByArg) {
4115   NameVals.push_back(args.size());
4116   llvm::append_range(NameVals, args);
4117 
4118   NameVals.push_back(ByArg.TheKind);
4119   NameVals.push_back(ByArg.Info);
4120   NameVals.push_back(ByArg.Byte);
4121   NameVals.push_back(ByArg.Bit);
4122 }
4123 
4124 static void writeWholeProgramDevirtResolution(
4125     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
4126     uint64_t Id, const WholeProgramDevirtResolution &Wpd) {
4127   NameVals.push_back(Id);
4128 
4129   NameVals.push_back(Wpd.TheKind);
4130   NameVals.push_back(StrtabBuilder.add(Wpd.SingleImplName));
4131   NameVals.push_back(Wpd.SingleImplName.size());
4132 
4133   NameVals.push_back(Wpd.ResByArg.size());
4134   for (auto &A : Wpd.ResByArg)
4135     writeWholeProgramDevirtResolutionByArg(NameVals, A.first, A.second);
4136 }
4137 
4138 static void writeTypeIdSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
4139                                      StringTableBuilder &StrtabBuilder,
4140                                      const std::string &Id,
4141                                      const TypeIdSummary &Summary) {
4142   NameVals.push_back(StrtabBuilder.add(Id));
4143   NameVals.push_back(Id.size());
4144 
4145   NameVals.push_back(Summary.TTRes.TheKind);
4146   NameVals.push_back(Summary.TTRes.SizeM1BitWidth);
4147   NameVals.push_back(Summary.TTRes.AlignLog2);
4148   NameVals.push_back(Summary.TTRes.SizeM1);
4149   NameVals.push_back(Summary.TTRes.BitMask);
4150   NameVals.push_back(Summary.TTRes.InlineBits);
4151 
4152   for (auto &W : Summary.WPDRes)
4153     writeWholeProgramDevirtResolution(NameVals, StrtabBuilder, W.first,
4154                                       W.second);
4155 }
4156 
4157 static void writeTypeIdCompatibleVtableSummaryRecord(
4158     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
4159     const std::string &Id, const TypeIdCompatibleVtableInfo &Summary,
4160     ValueEnumerator &VE) {
4161   NameVals.push_back(StrtabBuilder.add(Id));
4162   NameVals.push_back(Id.size());
4163 
4164   for (auto &P : Summary) {
4165     NameVals.push_back(P.AddressPointOffset);
4166     NameVals.push_back(VE.getValueID(P.VTableVI.getValue()));
4167   }
4168 }
4169 
4170 static void writeFunctionHeapProfileRecords(
4171     BitstreamWriter &Stream, FunctionSummary *FS, unsigned CallsiteAbbrev,
4172     unsigned AllocAbbrev, bool PerModule,
4173     std::function<unsigned(const ValueInfo &VI)> GetValueID,
4174     std::function<unsigned(unsigned)> GetStackIndex) {
4175   SmallVector<uint64_t> Record;
4176 
4177   for (auto &CI : FS->callsites()) {
4178     Record.clear();
4179     // Per module callsite clones should always have a single entry of
4180     // value 0.
4181     assert(!PerModule || (CI.Clones.size() == 1 && CI.Clones[0] == 0));
4182     Record.push_back(GetValueID(CI.Callee));
4183     if (!PerModule) {
4184       Record.push_back(CI.StackIdIndices.size());
4185       Record.push_back(CI.Clones.size());
4186     }
4187     for (auto Id : CI.StackIdIndices)
4188       Record.push_back(GetStackIndex(Id));
4189     if (!PerModule) {
4190       for (auto V : CI.Clones)
4191         Record.push_back(V);
4192     }
4193     Stream.EmitRecord(PerModule ? bitc::FS_PERMODULE_CALLSITE_INFO
4194                                 : bitc::FS_COMBINED_CALLSITE_INFO,
4195                       Record, CallsiteAbbrev);
4196   }
4197 
4198   for (auto &AI : FS->allocs()) {
4199     Record.clear();
4200     // Per module alloc versions should always have a single entry of
4201     // value 0.
4202     assert(!PerModule || (AI.Versions.size() == 1 && AI.Versions[0] == 0));
4203     Record.push_back(AI.MIBs.size());
4204     if (!PerModule)
4205       Record.push_back(AI.Versions.size());
4206     for (auto &MIB : AI.MIBs) {
4207       Record.push_back((uint8_t)MIB.AllocType);
4208       Record.push_back(MIB.StackIdIndices.size());
4209       for (auto Id : MIB.StackIdIndices)
4210         Record.push_back(GetStackIndex(Id));
4211     }
4212     if (!PerModule) {
4213       for (auto V : AI.Versions)
4214         Record.push_back(V);
4215     }
4216     assert(AI.TotalSizes.empty() || AI.TotalSizes.size() == AI.MIBs.size());
4217     if (!AI.TotalSizes.empty()) {
4218       for (auto Size : AI.TotalSizes)
4219         Record.push_back(Size);
4220     }
4221     Stream.EmitRecord(PerModule ? bitc::FS_PERMODULE_ALLOC_INFO
4222                                 : bitc::FS_COMBINED_ALLOC_INFO,
4223                       Record, AllocAbbrev);
4224   }
4225 }
4226 
4227 // Helper to emit a single function summary record.
4228 void ModuleBitcodeWriterBase::writePerModuleFunctionSummaryRecord(
4229     SmallVector<uint64_t, 64> &NameVals, GlobalValueSummary *Summary,
4230     unsigned ValueID, unsigned FSCallsRelBFAbbrev,
4231     unsigned FSCallsProfileAbbrev, unsigned CallsiteAbbrev,
4232     unsigned AllocAbbrev, const Function &F) {
4233   NameVals.push_back(ValueID);
4234 
4235   FunctionSummary *FS = cast<FunctionSummary>(Summary);
4236 
4237   writeFunctionTypeMetadataRecords(
4238       Stream, FS, [&](const ValueInfo &VI) -> std::optional<unsigned> {
4239         return {VE.getValueID(VI.getValue())};
4240       });
4241 
4242   writeFunctionHeapProfileRecords(
4243       Stream, FS, CallsiteAbbrev, AllocAbbrev,
4244       /*PerModule*/ true,
4245       /*GetValueId*/ [&](const ValueInfo &VI) { return getValueId(VI); },
4246       /*GetStackIndex*/ [&](unsigned I) { return I; });
4247 
4248   auto SpecialRefCnts = FS->specialRefCounts();
4249   NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
4250   NameVals.push_back(FS->instCount());
4251   NameVals.push_back(getEncodedFFlags(FS->fflags()));
4252   NameVals.push_back(FS->refs().size());
4253   NameVals.push_back(SpecialRefCnts.first);  // rorefcnt
4254   NameVals.push_back(SpecialRefCnts.second); // worefcnt
4255 
4256   for (auto &RI : FS->refs())
4257     NameVals.push_back(getValueId(RI));
4258 
4259   const bool UseRelBFRecord =
4260       WriteRelBFToSummary && !F.hasProfileData() &&
4261       ForceSummaryEdgesCold == FunctionSummary::FSHT_None;
4262   for (auto &ECI : FS->calls()) {
4263     NameVals.push_back(getValueId(ECI.first));
4264     if (UseRelBFRecord)
4265       NameVals.push_back(getEncodedRelBFCallEdgeInfo(ECI.second));
4266     else
4267       NameVals.push_back(getEncodedHotnessCallEdgeInfo(ECI.second));
4268   }
4269 
4270   unsigned FSAbbrev =
4271       (UseRelBFRecord ? FSCallsRelBFAbbrev : FSCallsProfileAbbrev);
4272   unsigned Code =
4273       (UseRelBFRecord ? bitc::FS_PERMODULE_RELBF : bitc::FS_PERMODULE_PROFILE);
4274 
4275   // Emit the finished record.
4276   Stream.EmitRecord(Code, NameVals, FSAbbrev);
4277   NameVals.clear();
4278 }
4279 
4280 // Collect the global value references in the given variable's initializer,
4281 // and emit them in a summary record.
4282 void ModuleBitcodeWriterBase::writeModuleLevelReferences(
4283     const GlobalVariable &V, SmallVector<uint64_t, 64> &NameVals,
4284     unsigned FSModRefsAbbrev, unsigned FSModVTableRefsAbbrev) {
4285   auto VI = Index->getValueInfo(V.getGUID());
4286   if (!VI || VI.getSummaryList().empty()) {
4287     // Only declarations should not have a summary (a declaration might however
4288     // have a summary if the def was in module level asm).
4289     assert(V.isDeclaration());
4290     return;
4291   }
4292   auto *Summary = VI.getSummaryList()[0].get();
4293   NameVals.push_back(VE.getValueID(&V));
4294   GlobalVarSummary *VS = cast<GlobalVarSummary>(Summary);
4295   NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
4296   NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
4297 
4298   auto VTableFuncs = VS->vTableFuncs();
4299   if (!VTableFuncs.empty())
4300     NameVals.push_back(VS->refs().size());
4301 
4302   unsigned SizeBeforeRefs = NameVals.size();
4303   for (auto &RI : VS->refs())
4304     NameVals.push_back(VE.getValueID(RI.getValue()));
4305   // Sort the refs for determinism output, the vector returned by FS->refs() has
4306   // been initialized from a DenseSet.
4307   llvm::sort(drop_begin(NameVals, SizeBeforeRefs));
4308 
4309   if (VTableFuncs.empty())
4310     Stream.EmitRecord(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS, NameVals,
4311                       FSModRefsAbbrev);
4312   else {
4313     // VTableFuncs pairs should already be sorted by offset.
4314     for (auto &P : VTableFuncs) {
4315       NameVals.push_back(VE.getValueID(P.FuncVI.getValue()));
4316       NameVals.push_back(P.VTableOffset);
4317     }
4318 
4319     Stream.EmitRecord(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS, NameVals,
4320                       FSModVTableRefsAbbrev);
4321   }
4322   NameVals.clear();
4323 }
4324 
4325 /// Emit the per-module summary section alongside the rest of
4326 /// the module's bitcode.
4327 void ModuleBitcodeWriterBase::writePerModuleGlobalValueSummary() {
4328   // By default we compile with ThinLTO if the module has a summary, but the
4329   // client can request full LTO with a module flag.
4330   bool IsThinLTO = true;
4331   if (auto *MD =
4332           mdconst::extract_or_null<ConstantInt>(M.getModuleFlag("ThinLTO")))
4333     IsThinLTO = MD->getZExtValue();
4334   Stream.EnterSubblock(IsThinLTO ? bitc::GLOBALVAL_SUMMARY_BLOCK_ID
4335                                  : bitc::FULL_LTO_GLOBALVAL_SUMMARY_BLOCK_ID,
4336                        4);
4337 
4338   Stream.EmitRecord(
4339       bitc::FS_VERSION,
4340       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
4341 
4342   // Write the index flags.
4343   uint64_t Flags = 0;
4344   // Bits 1-3 are set only in the combined index, skip them.
4345   if (Index->enableSplitLTOUnit())
4346     Flags |= 0x8;
4347   if (Index->hasUnifiedLTO())
4348     Flags |= 0x200;
4349 
4350   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Flags});
4351 
4352   if (Index->begin() == Index->end()) {
4353     Stream.ExitBlock();
4354     return;
4355   }
4356 
4357   auto Abbv = std::make_shared<BitCodeAbbrev>();
4358   Abbv->Add(BitCodeAbbrevOp(bitc::FS_VALUE_GUID));
4359   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
4360   // GUIDS often use up most of 64-bits, so encode as two Fixed 32.
4361   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
4362   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
4363   unsigned ValueGuidAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4364 
4365   for (const auto &GVI : valueIds()) {
4366     Stream.EmitRecord(bitc::FS_VALUE_GUID,
4367                       ArrayRef<uint32_t>{GVI.second,
4368                                          static_cast<uint32_t>(GVI.first >> 32),
4369                                          static_cast<uint32_t>(GVI.first)},
4370                       ValueGuidAbbrev);
4371   }
4372 
4373   if (!Index->stackIds().empty()) {
4374     auto StackIdAbbv = std::make_shared<BitCodeAbbrev>();
4375     StackIdAbbv->Add(BitCodeAbbrevOp(bitc::FS_STACK_IDS));
4376     // numids x stackid
4377     StackIdAbbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4378     StackIdAbbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4379     unsigned StackIdAbbvId = Stream.EmitAbbrev(std::move(StackIdAbbv));
4380     Stream.EmitRecord(bitc::FS_STACK_IDS, Index->stackIds(), StackIdAbbvId);
4381   }
4382 
4383   // Abbrev for FS_PERMODULE_PROFILE.
4384   Abbv = std::make_shared<BitCodeAbbrev>();
4385   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_PROFILE));
4386   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4387   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // flags
4388   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4389   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4390   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4391   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4392   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4393   // numrefs x valueid, n x (valueid, hotness+tailcall flags)
4394   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4395   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4396   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4397 
4398   // Abbrev for FS_PERMODULE_RELBF.
4399   Abbv = std::make_shared<BitCodeAbbrev>();
4400   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_RELBF));
4401   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4402   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4403   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4404   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4405   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4406   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4407   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4408   // numrefs x valueid, n x (valueid, rel_block_freq+tailcall])
4409   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4410   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4411   unsigned FSCallsRelBFAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4412 
4413   // Abbrev for FS_PERMODULE_GLOBALVAR_INIT_REFS.
4414   Abbv = std::make_shared<BitCodeAbbrev>();
4415   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS));
4416   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
4417   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
4418   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));  // valueids
4419   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4420   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4421 
4422   // Abbrev for FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS.
4423   Abbv = std::make_shared<BitCodeAbbrev>();
4424   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS));
4425   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
4426   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
4427   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numrefs
4428   // numrefs x valueid, n x (valueid , offset)
4429   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4430   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4431   unsigned FSModVTableRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4432 
4433   // Abbrev for FS_ALIAS.
4434   Abbv = std::make_shared<BitCodeAbbrev>();
4435   Abbv->Add(BitCodeAbbrevOp(bitc::FS_ALIAS));
4436   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4437   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4438   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4439   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4440 
4441   // Abbrev for FS_TYPE_ID_METADATA
4442   Abbv = std::make_shared<BitCodeAbbrev>();
4443   Abbv->Add(BitCodeAbbrevOp(bitc::FS_TYPE_ID_METADATA));
4444   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid strtab index
4445   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid length
4446   // n x (valueid , offset)
4447   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4448   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4449   unsigned TypeIdCompatibleVtableAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4450 
4451   Abbv = std::make_shared<BitCodeAbbrev>();
4452   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_CALLSITE_INFO));
4453   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
4454   // n x stackidindex
4455   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4456   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4457   unsigned CallsiteAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4458 
4459   Abbv = std::make_shared<BitCodeAbbrev>();
4460   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_ALLOC_INFO));
4461   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // nummib
4462   // n x (alloc type, numstackids, numstackids x stackidindex)
4463   // optional: nummib x total size
4464   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4465   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4466   unsigned AllocAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4467 
4468   SmallVector<uint64_t, 64> NameVals;
4469   // Iterate over the list of functions instead of the Index to
4470   // ensure the ordering is stable.
4471   for (const Function &F : M) {
4472     // Summary emission does not support anonymous functions, they have to
4473     // renamed using the anonymous function renaming pass.
4474     if (!F.hasName())
4475       report_fatal_error("Unexpected anonymous function when writing summary");
4476 
4477     ValueInfo VI = Index->getValueInfo(F.getGUID());
4478     if (!VI || VI.getSummaryList().empty()) {
4479       // Only declarations should not have a summary (a declaration might
4480       // however have a summary if the def was in module level asm).
4481       assert(F.isDeclaration());
4482       continue;
4483     }
4484     auto *Summary = VI.getSummaryList()[0].get();
4485     writePerModuleFunctionSummaryRecord(
4486         NameVals, Summary, VE.getValueID(&F), FSCallsRelBFAbbrev,
4487         FSCallsProfileAbbrev, CallsiteAbbrev, AllocAbbrev, F);
4488   }
4489 
4490   // Capture references from GlobalVariable initializers, which are outside
4491   // of a function scope.
4492   for (const GlobalVariable &G : M.globals())
4493     writeModuleLevelReferences(G, NameVals, FSModRefsAbbrev,
4494                                FSModVTableRefsAbbrev);
4495 
4496   for (const GlobalAlias &A : M.aliases()) {
4497     auto *Aliasee = A.getAliaseeObject();
4498     // Skip ifunc and nameless functions which don't have an entry in the
4499     // summary.
4500     if (!Aliasee->hasName() || isa<GlobalIFunc>(Aliasee))
4501       continue;
4502     auto AliasId = VE.getValueID(&A);
4503     auto AliaseeId = VE.getValueID(Aliasee);
4504     NameVals.push_back(AliasId);
4505     auto *Summary = Index->getGlobalValueSummary(A);
4506     AliasSummary *AS = cast<AliasSummary>(Summary);
4507     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
4508     NameVals.push_back(AliaseeId);
4509     Stream.EmitRecord(bitc::FS_ALIAS, NameVals, FSAliasAbbrev);
4510     NameVals.clear();
4511   }
4512 
4513   for (auto &S : Index->typeIdCompatibleVtableMap()) {
4514     writeTypeIdCompatibleVtableSummaryRecord(NameVals, StrtabBuilder, S.first,
4515                                              S.second, VE);
4516     Stream.EmitRecord(bitc::FS_TYPE_ID_METADATA, NameVals,
4517                       TypeIdCompatibleVtableAbbrev);
4518     NameVals.clear();
4519   }
4520 
4521   if (Index->getBlockCount())
4522     Stream.EmitRecord(bitc::FS_BLOCK_COUNT,
4523                       ArrayRef<uint64_t>{Index->getBlockCount()});
4524 
4525   Stream.ExitBlock();
4526 }
4527 
4528 /// Emit the combined summary section into the combined index file.
4529 void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
4530   Stream.EnterSubblock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID, 4);
4531   Stream.EmitRecord(
4532       bitc::FS_VERSION,
4533       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
4534 
4535   // Write the index flags.
4536   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Index.getFlags()});
4537 
4538   auto Abbv = std::make_shared<BitCodeAbbrev>();
4539   Abbv->Add(BitCodeAbbrevOp(bitc::FS_VALUE_GUID));
4540   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
4541   // GUIDS often use up most of 64-bits, so encode as two Fixed 32.
4542   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
4543   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
4544   unsigned ValueGuidAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4545 
4546   for (const auto &GVI : valueIds()) {
4547     Stream.EmitRecord(bitc::FS_VALUE_GUID,
4548                       ArrayRef<uint32_t>{GVI.second,
4549                                          static_cast<uint32_t>(GVI.first >> 32),
4550                                          static_cast<uint32_t>(GVI.first)},
4551                       ValueGuidAbbrev);
4552   }
4553 
4554   // Write the stack ids used by this index, which will be a subset of those in
4555   // the full index in the case of distributed indexes.
4556   if (!StackIds.empty()) {
4557     auto StackIdAbbv = std::make_shared<BitCodeAbbrev>();
4558     StackIdAbbv->Add(BitCodeAbbrevOp(bitc::FS_STACK_IDS));
4559     // numids x stackid
4560     StackIdAbbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4561     StackIdAbbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4562     unsigned StackIdAbbvId = Stream.EmitAbbrev(std::move(StackIdAbbv));
4563     Stream.EmitRecord(bitc::FS_STACK_IDS, StackIds, StackIdAbbvId);
4564   }
4565 
4566   // Abbrev for FS_COMBINED_PROFILE.
4567   Abbv = std::make_shared<BitCodeAbbrev>();
4568   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_PROFILE));
4569   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4570   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4571   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4572   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4573   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4574   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
4575   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4576   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4577   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4578   // numrefs x valueid, n x (valueid, hotness+tailcall flags)
4579   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4580   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4581   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4582 
4583   // Abbrev for FS_COMBINED_GLOBALVAR_INIT_REFS.
4584   Abbv = std::make_shared<BitCodeAbbrev>();
4585   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS));
4586   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4587   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4588   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4589   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));    // valueids
4590   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4591   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4592 
4593   // Abbrev for FS_COMBINED_ALIAS.
4594   Abbv = std::make_shared<BitCodeAbbrev>();
4595   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_ALIAS));
4596   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4597   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4598   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4599   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4600   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4601 
4602   Abbv = std::make_shared<BitCodeAbbrev>();
4603   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_CALLSITE_INFO));
4604   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
4605   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numstackindices
4606   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numver
4607   // numstackindices x stackidindex, numver x version
4608   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4609   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4610   unsigned CallsiteAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4611 
4612   Abbv = std::make_shared<BitCodeAbbrev>();
4613   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_ALLOC_INFO));
4614   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // nummib
4615   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numver
4616   // nummib x (alloc type, numstackids, numstackids x stackidindex),
4617   // numver x version
4618   // optional: nummib x total size
4619   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4620   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4621   unsigned AllocAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4622 
4623   auto shouldImportValueAsDecl = [&](GlobalValueSummary *GVS) -> bool {
4624     if (DecSummaries == nullptr)
4625       return false;
4626     return DecSummaries->count(GVS);
4627   };
4628 
4629   // The aliases are emitted as a post-pass, and will point to the value
4630   // id of the aliasee. Save them in a vector for post-processing.
4631   SmallVector<AliasSummary *, 64> Aliases;
4632 
4633   // Save the value id for each summary for alias emission.
4634   DenseMap<const GlobalValueSummary *, unsigned> SummaryToValueIdMap;
4635 
4636   SmallVector<uint64_t, 64> NameVals;
4637 
4638   // Set that will be populated during call to writeFunctionTypeMetadataRecords
4639   // with the type ids referenced by this index file.
4640   std::set<GlobalValue::GUID> ReferencedTypeIds;
4641 
4642   // For local linkage, we also emit the original name separately
4643   // immediately after the record.
4644   auto MaybeEmitOriginalName = [&](GlobalValueSummary &S) {
4645     // We don't need to emit the original name if we are writing the index for
4646     // distributed backends (in which case ModuleToSummariesForIndex is
4647     // non-null). The original name is only needed during the thin link, since
4648     // for SamplePGO the indirect call targets for local functions have
4649     // have the original name annotated in profile.
4650     // Continue to emit it when writing out the entire combined index, which is
4651     // used in testing the thin link via llvm-lto.
4652     if (ModuleToSummariesForIndex || !GlobalValue::isLocalLinkage(S.linkage()))
4653       return;
4654     NameVals.push_back(S.getOriginalName());
4655     Stream.EmitRecord(bitc::FS_COMBINED_ORIGINAL_NAME, NameVals);
4656     NameVals.clear();
4657   };
4658 
4659   DenseSet<GlobalValue::GUID> DefOrUseGUIDs;
4660   forEachSummary([&](GVInfo I, bool IsAliasee) {
4661     GlobalValueSummary *S = I.second;
4662     assert(S);
4663     DefOrUseGUIDs.insert(I.first);
4664     for (const ValueInfo &VI : S->refs())
4665       DefOrUseGUIDs.insert(VI.getGUID());
4666 
4667     auto ValueId = getValueId(I.first);
4668     assert(ValueId);
4669     SummaryToValueIdMap[S] = *ValueId;
4670 
4671     // If this is invoked for an aliasee, we want to record the above
4672     // mapping, but then not emit a summary entry (if the aliasee is
4673     // to be imported, we will invoke this separately with IsAliasee=false).
4674     if (IsAliasee)
4675       return;
4676 
4677     if (auto *AS = dyn_cast<AliasSummary>(S)) {
4678       // Will process aliases as a post-pass because the reader wants all
4679       // global to be loaded first.
4680       Aliases.push_back(AS);
4681       return;
4682     }
4683 
4684     if (auto *VS = dyn_cast<GlobalVarSummary>(S)) {
4685       NameVals.push_back(*ValueId);
4686       assert(ModuleIdMap.count(VS->modulePath()));
4687       NameVals.push_back(ModuleIdMap[VS->modulePath()]);
4688       NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
4689       NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
4690       for (auto &RI : VS->refs()) {
4691         auto RefValueId = getValueId(RI.getGUID());
4692         if (!RefValueId)
4693           continue;
4694         NameVals.push_back(*RefValueId);
4695       }
4696 
4697       // Emit the finished record.
4698       Stream.EmitRecord(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS, NameVals,
4699                         FSModRefsAbbrev);
4700       NameVals.clear();
4701       MaybeEmitOriginalName(*S);
4702       return;
4703     }
4704 
4705     auto GetValueId = [&](const ValueInfo &VI) -> std::optional<unsigned> {
4706       if (!VI)
4707         return std::nullopt;
4708       return getValueId(VI.getGUID());
4709     };
4710 
4711     auto *FS = cast<FunctionSummary>(S);
4712     writeFunctionTypeMetadataRecords(Stream, FS, GetValueId);
4713     getReferencedTypeIds(FS, ReferencedTypeIds);
4714 
4715     writeFunctionHeapProfileRecords(
4716         Stream, FS, CallsiteAbbrev, AllocAbbrev,
4717         /*PerModule*/ false,
4718         /*GetValueId*/
4719         [&](const ValueInfo &VI) -> unsigned {
4720           std::optional<unsigned> ValueID = GetValueId(VI);
4721           // This can happen in shared index files for distributed ThinLTO if
4722           // the callee function summary is not included. Record 0 which we
4723           // will have to deal with conservatively when doing any kind of
4724           // validation in the ThinLTO backends.
4725           if (!ValueID)
4726             return 0;
4727           return *ValueID;
4728         },
4729         /*GetStackIndex*/
4730         [&](unsigned I) {
4731           // Get the corresponding index into the list of StackIds actually
4732           // being written for this combined index (which may be a subset in
4733           // the case of distributed indexes).
4734           assert(StackIdIndicesToIndex.contains(I));
4735           return StackIdIndicesToIndex[I];
4736         });
4737 
4738     NameVals.push_back(*ValueId);
4739     assert(ModuleIdMap.count(FS->modulePath()));
4740     NameVals.push_back(ModuleIdMap[FS->modulePath()]);
4741     NameVals.push_back(
4742         getEncodedGVSummaryFlags(FS->flags(), shouldImportValueAsDecl(FS)));
4743     NameVals.push_back(FS->instCount());
4744     NameVals.push_back(getEncodedFFlags(FS->fflags()));
4745     // TODO: Stop writing entry count and bump bitcode version.
4746     NameVals.push_back(0 /* EntryCount */);
4747 
4748     // Fill in below
4749     NameVals.push_back(0); // numrefs
4750     NameVals.push_back(0); // rorefcnt
4751     NameVals.push_back(0); // worefcnt
4752 
4753     unsigned Count = 0, RORefCnt = 0, WORefCnt = 0;
4754     for (auto &RI : FS->refs()) {
4755       auto RefValueId = getValueId(RI.getGUID());
4756       if (!RefValueId)
4757         continue;
4758       NameVals.push_back(*RefValueId);
4759       if (RI.isReadOnly())
4760         RORefCnt++;
4761       else if (RI.isWriteOnly())
4762         WORefCnt++;
4763       Count++;
4764     }
4765     NameVals[6] = Count;
4766     NameVals[7] = RORefCnt;
4767     NameVals[8] = WORefCnt;
4768 
4769     for (auto &EI : FS->calls()) {
4770       // If this GUID doesn't have a value id, it doesn't have a function
4771       // summary and we don't need to record any calls to it.
4772       std::optional<unsigned> CallValueId = GetValueId(EI.first);
4773       if (!CallValueId)
4774         continue;
4775       NameVals.push_back(*CallValueId);
4776       NameVals.push_back(getEncodedHotnessCallEdgeInfo(EI.second));
4777     }
4778 
4779     // Emit the finished record.
4780     Stream.EmitRecord(bitc::FS_COMBINED_PROFILE, NameVals,
4781                       FSCallsProfileAbbrev);
4782     NameVals.clear();
4783     MaybeEmitOriginalName(*S);
4784   });
4785 
4786   for (auto *AS : Aliases) {
4787     auto AliasValueId = SummaryToValueIdMap[AS];
4788     assert(AliasValueId);
4789     NameVals.push_back(AliasValueId);
4790     assert(ModuleIdMap.count(AS->modulePath()));
4791     NameVals.push_back(ModuleIdMap[AS->modulePath()]);
4792     NameVals.push_back(
4793         getEncodedGVSummaryFlags(AS->flags(), shouldImportValueAsDecl(AS)));
4794     auto AliaseeValueId = SummaryToValueIdMap[&AS->getAliasee()];
4795     assert(AliaseeValueId);
4796     NameVals.push_back(AliaseeValueId);
4797 
4798     // Emit the finished record.
4799     Stream.EmitRecord(bitc::FS_COMBINED_ALIAS, NameVals, FSAliasAbbrev);
4800     NameVals.clear();
4801     MaybeEmitOriginalName(*AS);
4802 
4803     if (auto *FS = dyn_cast<FunctionSummary>(&AS->getAliasee()))
4804       getReferencedTypeIds(FS, ReferencedTypeIds);
4805   }
4806 
4807   if (!Index.cfiFunctionDefs().empty()) {
4808     for (auto &S : Index.cfiFunctionDefs()) {
4809       if (DefOrUseGUIDs.contains(
4810               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4811         NameVals.push_back(StrtabBuilder.add(S));
4812         NameVals.push_back(S.size());
4813       }
4814     }
4815     if (!NameVals.empty()) {
4816       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DEFS, NameVals);
4817       NameVals.clear();
4818     }
4819   }
4820 
4821   if (!Index.cfiFunctionDecls().empty()) {
4822     for (auto &S : Index.cfiFunctionDecls()) {
4823       if (DefOrUseGUIDs.contains(
4824               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4825         NameVals.push_back(StrtabBuilder.add(S));
4826         NameVals.push_back(S.size());
4827       }
4828     }
4829     if (!NameVals.empty()) {
4830       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DECLS, NameVals);
4831       NameVals.clear();
4832     }
4833   }
4834 
4835   // Walk the GUIDs that were referenced, and write the
4836   // corresponding type id records.
4837   for (auto &T : ReferencedTypeIds) {
4838     auto TidIter = Index.typeIds().equal_range(T);
4839     for (const auto &[GUID, TypeIdPair] : make_range(TidIter)) {
4840       writeTypeIdSummaryRecord(NameVals, StrtabBuilder, TypeIdPair.first,
4841                                TypeIdPair.second);
4842       Stream.EmitRecord(bitc::FS_TYPE_ID, NameVals);
4843       NameVals.clear();
4844     }
4845   }
4846 
4847   if (Index.getBlockCount())
4848     Stream.EmitRecord(bitc::FS_BLOCK_COUNT,
4849                       ArrayRef<uint64_t>{Index.getBlockCount()});
4850 
4851   Stream.ExitBlock();
4852 }
4853 
4854 /// Create the "IDENTIFICATION_BLOCK_ID" containing a single string with the
4855 /// current llvm version, and a record for the epoch number.
4856 static void writeIdentificationBlock(BitstreamWriter &Stream) {
4857   Stream.EnterSubblock(bitc::IDENTIFICATION_BLOCK_ID, 5);
4858 
4859   // Write the "user readable" string identifying the bitcode producer
4860   auto Abbv = std::make_shared<BitCodeAbbrev>();
4861   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_STRING));
4862   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4863   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
4864   auto StringAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4865   writeStringRecord(Stream, bitc::IDENTIFICATION_CODE_STRING,
4866                     "LLVM" LLVM_VERSION_STRING, StringAbbrev);
4867 
4868   // Write the epoch version
4869   Abbv = std::make_shared<BitCodeAbbrev>();
4870   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_EPOCH));
4871   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
4872   auto EpochAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4873   constexpr std::array<unsigned, 1> Vals = {{bitc::BITCODE_CURRENT_EPOCH}};
4874   Stream.EmitRecord(bitc::IDENTIFICATION_CODE_EPOCH, Vals, EpochAbbrev);
4875   Stream.ExitBlock();
4876 }
4877 
4878 void ModuleBitcodeWriter::writeModuleHash(StringRef View) {
4879   // Emit the module's hash.
4880   // MODULE_CODE_HASH: [5*i32]
4881   if (GenerateHash) {
4882     uint32_t Vals[5];
4883     Hasher.update(ArrayRef<uint8_t>(
4884         reinterpret_cast<const uint8_t *>(View.data()), View.size()));
4885     std::array<uint8_t, 20> Hash = Hasher.result();
4886     for (int Pos = 0; Pos < 20; Pos += 4) {
4887       Vals[Pos / 4] = support::endian::read32be(Hash.data() + Pos);
4888     }
4889 
4890     // Emit the finished record.
4891     Stream.EmitRecord(bitc::MODULE_CODE_HASH, Vals);
4892 
4893     if (ModHash)
4894       // Save the written hash value.
4895       llvm::copy(Vals, std::begin(*ModHash));
4896   }
4897 }
4898 
4899 void ModuleBitcodeWriter::write() {
4900   writeIdentificationBlock(Stream);
4901 
4902   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4903   // We will want to write the module hash at this point. Block any flushing so
4904   // we can have access to the whole underlying data later.
4905   Stream.markAndBlockFlushing();
4906 
4907   writeModuleVersion();
4908 
4909   // Emit blockinfo, which defines the standard abbreviations etc.
4910   writeBlockInfo();
4911 
4912   // Emit information describing all of the types in the module.
4913   writeTypeTable();
4914 
4915   // Emit information about attribute groups.
4916   writeAttributeGroupTable();
4917 
4918   // Emit information about parameter attributes.
4919   writeAttributeTable();
4920 
4921   writeComdats();
4922 
4923   // Emit top-level description of module, including target triple, inline asm,
4924   // descriptors for global variables, and function prototype info.
4925   writeModuleInfo();
4926 
4927   // Emit constants.
4928   writeModuleConstants();
4929 
4930   // Emit metadata kind names.
4931   writeModuleMetadataKinds();
4932 
4933   // Emit metadata.
4934   writeModuleMetadata();
4935 
4936   // Emit module-level use-lists.
4937   if (VE.shouldPreserveUseListOrder())
4938     writeUseListBlock(nullptr);
4939 
4940   writeOperandBundleTags();
4941   writeSyncScopeNames();
4942 
4943   // Emit function bodies.
4944   DenseMap<const Function *, uint64_t> FunctionToBitcodeIndex;
4945   for (const Function &F : M)
4946     if (!F.isDeclaration())
4947       writeFunction(F, FunctionToBitcodeIndex);
4948 
4949   // Need to write after the above call to WriteFunction which populates
4950   // the summary information in the index.
4951   if (Index)
4952     writePerModuleGlobalValueSummary();
4953 
4954   writeGlobalValueSymbolTable(FunctionToBitcodeIndex);
4955 
4956   writeModuleHash(Stream.getMarkedBufferAndResumeFlushing());
4957 
4958   Stream.ExitBlock();
4959 }
4960 
4961 static void writeInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
4962                                uint32_t &Position) {
4963   support::endian::write32le(&Buffer[Position], Value);
4964   Position += 4;
4965 }
4966 
4967 /// If generating a bc file on darwin, we have to emit a
4968 /// header and trailer to make it compatible with the system archiver.  To do
4969 /// this we emit the following header, and then emit a trailer that pads the
4970 /// file out to be a multiple of 16 bytes.
4971 ///
4972 /// struct bc_header {
4973 ///   uint32_t Magic;         // 0x0B17C0DE
4974 ///   uint32_t Version;       // Version, currently always 0.
4975 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
4976 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
4977 ///   uint32_t CPUType;       // CPU specifier.
4978 ///   ... potentially more later ...
4979 /// };
4980 static void emitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
4981                                          const Triple &TT) {
4982   unsigned CPUType = ~0U;
4983 
4984   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
4985   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
4986   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
4987   // specific constants here because they are implicitly part of the Darwin ABI.
4988   enum {
4989     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
4990     DARWIN_CPU_TYPE_X86        = 7,
4991     DARWIN_CPU_TYPE_ARM        = 12,
4992     DARWIN_CPU_TYPE_POWERPC    = 18
4993   };
4994 
4995   Triple::ArchType Arch = TT.getArch();
4996   if (Arch == Triple::x86_64)
4997     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
4998   else if (Arch == Triple::x86)
4999     CPUType = DARWIN_CPU_TYPE_X86;
5000   else if (Arch == Triple::ppc)
5001     CPUType = DARWIN_CPU_TYPE_POWERPC;
5002   else if (Arch == Triple::ppc64)
5003     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
5004   else if (Arch == Triple::arm || Arch == Triple::thumb)
5005     CPUType = DARWIN_CPU_TYPE_ARM;
5006 
5007   // Traditional Bitcode starts after header.
5008   assert(Buffer.size() >= BWH_HeaderSize &&
5009          "Expected header size to be reserved");
5010   unsigned BCOffset = BWH_HeaderSize;
5011   unsigned BCSize = Buffer.size() - BWH_HeaderSize;
5012 
5013   // Write the magic and version.
5014   unsigned Position = 0;
5015   writeInt32ToBuffer(0x0B17C0DE, Buffer, Position);
5016   writeInt32ToBuffer(0, Buffer, Position); // Version.
5017   writeInt32ToBuffer(BCOffset, Buffer, Position);
5018   writeInt32ToBuffer(BCSize, Buffer, Position);
5019   writeInt32ToBuffer(CPUType, Buffer, Position);
5020 
5021   // If the file is not a multiple of 16 bytes, insert dummy padding.
5022   while (Buffer.size() & 15)
5023     Buffer.push_back(0);
5024 }
5025 
5026 /// Helper to write the header common to all bitcode files.
5027 static void writeBitcodeHeader(BitstreamWriter &Stream) {
5028   // Emit the file header.
5029   Stream.Emit((unsigned)'B', 8);
5030   Stream.Emit((unsigned)'C', 8);
5031   Stream.Emit(0x0, 4);
5032   Stream.Emit(0xC, 4);
5033   Stream.Emit(0xE, 4);
5034   Stream.Emit(0xD, 4);
5035 }
5036 
5037 BitcodeWriter::BitcodeWriter(SmallVectorImpl<char> &Buffer)
5038     : Stream(new BitstreamWriter(Buffer)) {
5039   writeBitcodeHeader(*Stream);
5040 }
5041 
5042 BitcodeWriter::BitcodeWriter(raw_ostream &FS)
5043     : Stream(new BitstreamWriter(FS, FlushThreshold)) {
5044   writeBitcodeHeader(*Stream);
5045 }
5046 
5047 BitcodeWriter::~BitcodeWriter() { assert(WroteStrtab); }
5048 
5049 void BitcodeWriter::writeBlob(unsigned Block, unsigned Record, StringRef Blob) {
5050   Stream->EnterSubblock(Block, 3);
5051 
5052   auto Abbv = std::make_shared<BitCodeAbbrev>();
5053   Abbv->Add(BitCodeAbbrevOp(Record));
5054   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
5055   auto AbbrevNo = Stream->EmitAbbrev(std::move(Abbv));
5056 
5057   Stream->EmitRecordWithBlob(AbbrevNo, ArrayRef<uint64_t>{Record}, Blob);
5058 
5059   Stream->ExitBlock();
5060 }
5061 
5062 void BitcodeWriter::writeSymtab() {
5063   assert(!WroteStrtab && !WroteSymtab);
5064 
5065   // If any module has module-level inline asm, we will require a registered asm
5066   // parser for the target so that we can create an accurate symbol table for
5067   // the module.
5068   for (Module *M : Mods) {
5069     if (M->getModuleInlineAsm().empty())
5070       continue;
5071 
5072     std::string Err;
5073     const Triple TT(M->getTargetTriple());
5074     const Target *T = TargetRegistry::lookupTarget(TT.str(), Err);
5075     if (!T || !T->hasMCAsmParser())
5076       return;
5077   }
5078 
5079   WroteSymtab = true;
5080   SmallVector<char, 0> Symtab;
5081   // The irsymtab::build function may be unable to create a symbol table if the
5082   // module is malformed (e.g. it contains an invalid alias). Writing a symbol
5083   // table is not required for correctness, but we still want to be able to
5084   // write malformed modules to bitcode files, so swallow the error.
5085   if (Error E = irsymtab::build(Mods, Symtab, StrtabBuilder, Alloc)) {
5086     consumeError(std::move(E));
5087     return;
5088   }
5089 
5090   writeBlob(bitc::SYMTAB_BLOCK_ID, bitc::SYMTAB_BLOB,
5091             {Symtab.data(), Symtab.size()});
5092 }
5093 
5094 void BitcodeWriter::writeStrtab() {
5095   assert(!WroteStrtab);
5096 
5097   std::vector<char> Strtab;
5098   StrtabBuilder.finalizeInOrder();
5099   Strtab.resize(StrtabBuilder.getSize());
5100   StrtabBuilder.write((uint8_t *)Strtab.data());
5101 
5102   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB,
5103             {Strtab.data(), Strtab.size()});
5104 
5105   WroteStrtab = true;
5106 }
5107 
5108 void BitcodeWriter::copyStrtab(StringRef Strtab) {
5109   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB, Strtab);
5110   WroteStrtab = true;
5111 }
5112 
5113 void BitcodeWriter::writeModule(const Module &M,
5114                                 bool ShouldPreserveUseListOrder,
5115                                 const ModuleSummaryIndex *Index,
5116                                 bool GenerateHash, ModuleHash *ModHash) {
5117   assert(!WroteStrtab);
5118 
5119   // The Mods vector is used by irsymtab::build, which requires non-const
5120   // Modules in case it needs to materialize metadata. But the bitcode writer
5121   // requires that the module is materialized, so we can cast to non-const here,
5122   // after checking that it is in fact materialized.
5123   assert(M.isMaterialized());
5124   Mods.push_back(const_cast<Module *>(&M));
5125 
5126   ModuleBitcodeWriter ModuleWriter(M, StrtabBuilder, *Stream,
5127                                    ShouldPreserveUseListOrder, Index,
5128                                    GenerateHash, ModHash);
5129   ModuleWriter.write();
5130 }
5131 
5132 void BitcodeWriter::writeIndex(
5133     const ModuleSummaryIndex *Index,
5134     const ModuleToSummariesForIndexTy *ModuleToSummariesForIndex,
5135     const GVSummaryPtrSet *DecSummaries) {
5136   IndexBitcodeWriter IndexWriter(*Stream, StrtabBuilder, *Index, DecSummaries,
5137                                  ModuleToSummariesForIndex);
5138   IndexWriter.write();
5139 }
5140 
5141 /// Write the specified module to the specified output stream.
5142 void llvm::WriteBitcodeToFile(const Module &M, raw_ostream &Out,
5143                               bool ShouldPreserveUseListOrder,
5144                               const ModuleSummaryIndex *Index,
5145                               bool GenerateHash, ModuleHash *ModHash) {
5146   auto Write = [&](BitcodeWriter &Writer) {
5147     Writer.writeModule(M, ShouldPreserveUseListOrder, Index, GenerateHash,
5148                        ModHash);
5149     Writer.writeSymtab();
5150     Writer.writeStrtab();
5151   };
5152   Triple TT(M.getTargetTriple());
5153   if (TT.isOSDarwin() || TT.isOSBinFormatMachO()) {
5154     // If this is darwin or another generic macho target, reserve space for the
5155     // header. Note that the header is computed *after* the output is known, so
5156     // we currently explicitly use a buffer, write to it, and then subsequently
5157     // flush to Out.
5158     SmallVector<char, 0> Buffer;
5159     Buffer.reserve(256 * 1024);
5160     Buffer.insert(Buffer.begin(), BWH_HeaderSize, 0);
5161     BitcodeWriter Writer(Buffer);
5162     Write(Writer);
5163     emitDarwinBCHeaderAndTrailer(Buffer, TT);
5164     Out.write(Buffer.data(), Buffer.size());
5165   } else {
5166     BitcodeWriter Writer(Out);
5167     Write(Writer);
5168   }
5169 }
5170 
5171 void IndexBitcodeWriter::write() {
5172   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
5173 
5174   writeModuleVersion();
5175 
5176   // Write the module paths in the combined index.
5177   writeModStrings();
5178 
5179   // Write the summary combined index records.
5180   writeCombinedGlobalValueSummary();
5181 
5182   Stream.ExitBlock();
5183 }
5184 
5185 // Write the specified module summary index to the given raw output stream,
5186 // where it will be written in a new bitcode block. This is used when
5187 // writing the combined index file for ThinLTO. When writing a subset of the
5188 // index for a distributed backend, provide a \p ModuleToSummariesForIndex map.
5189 void llvm::writeIndexToFile(
5190     const ModuleSummaryIndex &Index, raw_ostream &Out,
5191     const ModuleToSummariesForIndexTy *ModuleToSummariesForIndex,
5192     const GVSummaryPtrSet *DecSummaries) {
5193   SmallVector<char, 0> Buffer;
5194   Buffer.reserve(256 * 1024);
5195 
5196   BitcodeWriter Writer(Buffer);
5197   Writer.writeIndex(&Index, ModuleToSummariesForIndex, DecSummaries);
5198   Writer.writeStrtab();
5199 
5200   Out.write((char *)&Buffer.front(), Buffer.size());
5201 }
5202 
5203 namespace {
5204 
5205 /// Class to manage the bitcode writing for a thin link bitcode file.
5206 class ThinLinkBitcodeWriter : public ModuleBitcodeWriterBase {
5207   /// ModHash is for use in ThinLTO incremental build, generated while writing
5208   /// the module bitcode file.
5209   const ModuleHash *ModHash;
5210 
5211 public:
5212   ThinLinkBitcodeWriter(const Module &M, StringTableBuilder &StrtabBuilder,
5213                         BitstreamWriter &Stream,
5214                         const ModuleSummaryIndex &Index,
5215                         const ModuleHash &ModHash)
5216       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
5217                                 /*ShouldPreserveUseListOrder=*/false, &Index),
5218         ModHash(&ModHash) {}
5219 
5220   void write();
5221 
5222 private:
5223   void writeSimplifiedModuleInfo();
5224 };
5225 
5226 } // end anonymous namespace
5227 
5228 // This function writes a simpilified module info for thin link bitcode file.
5229 // It only contains the source file name along with the name(the offset and
5230 // size in strtab) and linkage for global values. For the global value info
5231 // entry, in order to keep linkage at offset 5, there are three zeros used
5232 // as padding.
5233 void ThinLinkBitcodeWriter::writeSimplifiedModuleInfo() {
5234   SmallVector<unsigned, 64> Vals;
5235   // Emit the module's source file name.
5236   {
5237     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
5238     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
5239     if (Bits == SE_Char6)
5240       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
5241     else if (Bits == SE_Fixed7)
5242       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
5243 
5244     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
5245     auto Abbv = std::make_shared<BitCodeAbbrev>();
5246     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
5247     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
5248     Abbv->Add(AbbrevOpToUse);
5249     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
5250 
5251     for (const auto P : M.getSourceFileName())
5252       Vals.push_back((unsigned char)P);
5253 
5254     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
5255     Vals.clear();
5256   }
5257 
5258   // Emit the global variable information.
5259   for (const GlobalVariable &GV : M.globals()) {
5260     // GLOBALVAR: [strtab offset, strtab size, 0, 0, 0, linkage]
5261     Vals.push_back(StrtabBuilder.add(GV.getName()));
5262     Vals.push_back(GV.getName().size());
5263     Vals.push_back(0);
5264     Vals.push_back(0);
5265     Vals.push_back(0);
5266     Vals.push_back(getEncodedLinkage(GV));
5267 
5268     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals);
5269     Vals.clear();
5270   }
5271 
5272   // Emit the function proto information.
5273   for (const Function &F : M) {
5274     // FUNCTION:  [strtab offset, strtab size, 0, 0, 0, linkage]
5275     Vals.push_back(StrtabBuilder.add(F.getName()));
5276     Vals.push_back(F.getName().size());
5277     Vals.push_back(0);
5278     Vals.push_back(0);
5279     Vals.push_back(0);
5280     Vals.push_back(getEncodedLinkage(F));
5281 
5282     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals);
5283     Vals.clear();
5284   }
5285 
5286   // Emit the alias information.
5287   for (const GlobalAlias &A : M.aliases()) {
5288     // ALIAS: [strtab offset, strtab size, 0, 0, 0, linkage]
5289     Vals.push_back(StrtabBuilder.add(A.getName()));
5290     Vals.push_back(A.getName().size());
5291     Vals.push_back(0);
5292     Vals.push_back(0);
5293     Vals.push_back(0);
5294     Vals.push_back(getEncodedLinkage(A));
5295 
5296     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals);
5297     Vals.clear();
5298   }
5299 
5300   // Emit the ifunc information.
5301   for (const GlobalIFunc &I : M.ifuncs()) {
5302     // IFUNC: [strtab offset, strtab size, 0, 0, 0, linkage]
5303     Vals.push_back(StrtabBuilder.add(I.getName()));
5304     Vals.push_back(I.getName().size());
5305     Vals.push_back(0);
5306     Vals.push_back(0);
5307     Vals.push_back(0);
5308     Vals.push_back(getEncodedLinkage(I));
5309 
5310     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
5311     Vals.clear();
5312   }
5313 }
5314 
5315 void ThinLinkBitcodeWriter::write() {
5316   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
5317 
5318   writeModuleVersion();
5319 
5320   writeSimplifiedModuleInfo();
5321 
5322   writePerModuleGlobalValueSummary();
5323 
5324   // Write module hash.
5325   Stream.EmitRecord(bitc::MODULE_CODE_HASH, ArrayRef<uint32_t>(*ModHash));
5326 
5327   Stream.ExitBlock();
5328 }
5329 
5330 void BitcodeWriter::writeThinLinkBitcode(const Module &M,
5331                                          const ModuleSummaryIndex &Index,
5332                                          const ModuleHash &ModHash) {
5333   assert(!WroteStrtab);
5334 
5335   // The Mods vector is used by irsymtab::build, which requires non-const
5336   // Modules in case it needs to materialize metadata. But the bitcode writer
5337   // requires that the module is materialized, so we can cast to non-const here,
5338   // after checking that it is in fact materialized.
5339   assert(M.isMaterialized());
5340   Mods.push_back(const_cast<Module *>(&M));
5341 
5342   ThinLinkBitcodeWriter ThinLinkWriter(M, StrtabBuilder, *Stream, Index,
5343                                        ModHash);
5344   ThinLinkWriter.write();
5345 }
5346 
5347 // Write the specified thin link bitcode file to the given raw output stream,
5348 // where it will be written in a new bitcode block. This is used when
5349 // writing the per-module index file for ThinLTO.
5350 void llvm::writeThinLinkBitcodeToFile(const Module &M, raw_ostream &Out,
5351                                       const ModuleSummaryIndex &Index,
5352                                       const ModuleHash &ModHash) {
5353   SmallVector<char, 0> Buffer;
5354   Buffer.reserve(256 * 1024);
5355 
5356   BitcodeWriter Writer(Buffer);
5357   Writer.writeThinLinkBitcode(M, Index, ModHash);
5358   Writer.writeSymtab();
5359   Writer.writeStrtab();
5360 
5361   Out.write((char *)&Buffer.front(), Buffer.size());
5362 }
5363 
5364 static const char *getSectionNameForBitcode(const Triple &T) {
5365   switch (T.getObjectFormat()) {
5366   case Triple::MachO:
5367     return "__LLVM,__bitcode";
5368   case Triple::COFF:
5369   case Triple::ELF:
5370   case Triple::Wasm:
5371   case Triple::UnknownObjectFormat:
5372     return ".llvmbc";
5373   case Triple::GOFF:
5374     llvm_unreachable("GOFF is not yet implemented");
5375     break;
5376   case Triple::SPIRV:
5377     if (T.getVendor() == Triple::AMD)
5378       return ".llvmbc";
5379     llvm_unreachable("SPIRV is not yet implemented");
5380     break;
5381   case Triple::XCOFF:
5382     llvm_unreachable("XCOFF is not yet implemented");
5383     break;
5384   case Triple::DXContainer:
5385     llvm_unreachable("DXContainer is not yet implemented");
5386     break;
5387   }
5388   llvm_unreachable("Unimplemented ObjectFormatType");
5389 }
5390 
5391 static const char *getSectionNameForCommandline(const Triple &T) {
5392   switch (T.getObjectFormat()) {
5393   case Triple::MachO:
5394     return "__LLVM,__cmdline";
5395   case Triple::COFF:
5396   case Triple::ELF:
5397   case Triple::Wasm:
5398   case Triple::UnknownObjectFormat:
5399     return ".llvmcmd";
5400   case Triple::GOFF:
5401     llvm_unreachable("GOFF is not yet implemented");
5402     break;
5403   case Triple::SPIRV:
5404     if (T.getVendor() == Triple::AMD)
5405       return ".llvmcmd";
5406     llvm_unreachable("SPIRV is not yet implemented");
5407     break;
5408   case Triple::XCOFF:
5409     llvm_unreachable("XCOFF is not yet implemented");
5410     break;
5411   case Triple::DXContainer:
5412     llvm_unreachable("DXC is not yet implemented");
5413     break;
5414   }
5415   llvm_unreachable("Unimplemented ObjectFormatType");
5416 }
5417 
5418 void llvm::embedBitcodeInModule(llvm::Module &M, llvm::MemoryBufferRef Buf,
5419                                 bool EmbedBitcode, bool EmbedCmdline,
5420                                 const std::vector<uint8_t> &CmdArgs) {
5421   // Save llvm.compiler.used and remove it.
5422   SmallVector<Constant *, 2> UsedArray;
5423   SmallVector<GlobalValue *, 4> UsedGlobals;
5424   Type *UsedElementType = PointerType::getUnqual(M.getContext());
5425   GlobalVariable *Used = collectUsedGlobalVariables(M, UsedGlobals, true);
5426   for (auto *GV : UsedGlobals) {
5427     if (GV->getName() != "llvm.embedded.module" &&
5428         GV->getName() != "llvm.cmdline")
5429       UsedArray.push_back(
5430           ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
5431   }
5432   if (Used)
5433     Used->eraseFromParent();
5434 
5435   // Embed the bitcode for the llvm module.
5436   std::string Data;
5437   ArrayRef<uint8_t> ModuleData;
5438   Triple T(M.getTargetTriple());
5439 
5440   if (EmbedBitcode) {
5441     if (Buf.getBufferSize() == 0 ||
5442         !isBitcode((const unsigned char *)Buf.getBufferStart(),
5443                    (const unsigned char *)Buf.getBufferEnd())) {
5444       // If the input is LLVM Assembly, bitcode is produced by serializing
5445       // the module. Use-lists order need to be preserved in this case.
5446       llvm::raw_string_ostream OS(Data);
5447       llvm::WriteBitcodeToFile(M, OS, /* ShouldPreserveUseListOrder */ true);
5448       ModuleData =
5449           ArrayRef<uint8_t>((const uint8_t *)OS.str().data(), OS.str().size());
5450     } else
5451       // If the input is LLVM bitcode, write the input byte stream directly.
5452       ModuleData = ArrayRef<uint8_t>((const uint8_t *)Buf.getBufferStart(),
5453                                      Buf.getBufferSize());
5454   }
5455   llvm::Constant *ModuleConstant =
5456       llvm::ConstantDataArray::get(M.getContext(), ModuleData);
5457   llvm::GlobalVariable *GV = new llvm::GlobalVariable(
5458       M, ModuleConstant->getType(), true, llvm::GlobalValue::PrivateLinkage,
5459       ModuleConstant);
5460   GV->setSection(getSectionNameForBitcode(T));
5461   // Set alignment to 1 to prevent padding between two contributions from input
5462   // sections after linking.
5463   GV->setAlignment(Align(1));
5464   UsedArray.push_back(
5465       ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
5466   if (llvm::GlobalVariable *Old =
5467           M.getGlobalVariable("llvm.embedded.module", true)) {
5468     assert(Old->hasZeroLiveUses() &&
5469            "llvm.embedded.module can only be used once in llvm.compiler.used");
5470     GV->takeName(Old);
5471     Old->eraseFromParent();
5472   } else {
5473     GV->setName("llvm.embedded.module");
5474   }
5475 
5476   // Skip if only bitcode needs to be embedded.
5477   if (EmbedCmdline) {
5478     // Embed command-line options.
5479     ArrayRef<uint8_t> CmdData(const_cast<uint8_t *>(CmdArgs.data()),
5480                               CmdArgs.size());
5481     llvm::Constant *CmdConstant =
5482         llvm::ConstantDataArray::get(M.getContext(), CmdData);
5483     GV = new llvm::GlobalVariable(M, CmdConstant->getType(), true,
5484                                   llvm::GlobalValue::PrivateLinkage,
5485                                   CmdConstant);
5486     GV->setSection(getSectionNameForCommandline(T));
5487     GV->setAlignment(Align(1));
5488     UsedArray.push_back(
5489         ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
5490     if (llvm::GlobalVariable *Old = M.getGlobalVariable("llvm.cmdline", true)) {
5491       assert(Old->hasZeroLiveUses() &&
5492              "llvm.cmdline can only be used once in llvm.compiler.used");
5493       GV->takeName(Old);
5494       Old->eraseFromParent();
5495     } else {
5496       GV->setName("llvm.cmdline");
5497     }
5498   }
5499 
5500   if (UsedArray.empty())
5501     return;
5502 
5503   // Recreate llvm.compiler.used.
5504   ArrayType *ATy = ArrayType::get(UsedElementType, UsedArray.size());
5505   auto *NewUsed = new GlobalVariable(
5506       M, ATy, false, llvm::GlobalValue::AppendingLinkage,
5507       llvm::ConstantArray::get(ATy, UsedArray), "llvm.compiler.used");
5508   NewUsed->setSection("llvm.metadata");
5509 }
5510