xref: /llvm-project/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp (revision 0f488a0b7d3da3c736e9242e5dd110ba0322e45a)
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::SanitizeRealtimeUnsafe:
853     return bitc::ATTR_KIND_SANITIZE_REALTIME_UNSAFE;
854   case Attribute::SpeculativeLoadHardening:
855     return bitc::ATTR_KIND_SPECULATIVE_LOAD_HARDENING;
856   case Attribute::SwiftError:
857     return bitc::ATTR_KIND_SWIFT_ERROR;
858   case Attribute::SwiftSelf:
859     return bitc::ATTR_KIND_SWIFT_SELF;
860   case Attribute::SwiftAsync:
861     return bitc::ATTR_KIND_SWIFT_ASYNC;
862   case Attribute::UWTable:
863     return bitc::ATTR_KIND_UW_TABLE;
864   case Attribute::VScaleRange:
865     return bitc::ATTR_KIND_VSCALE_RANGE;
866   case Attribute::WillReturn:
867     return bitc::ATTR_KIND_WILLRETURN;
868   case Attribute::WriteOnly:
869     return bitc::ATTR_KIND_WRITEONLY;
870   case Attribute::ZExt:
871     return bitc::ATTR_KIND_Z_EXT;
872   case Attribute::ImmArg:
873     return bitc::ATTR_KIND_IMMARG;
874   case Attribute::SanitizeMemTag:
875     return bitc::ATTR_KIND_SANITIZE_MEMTAG;
876   case Attribute::Preallocated:
877     return bitc::ATTR_KIND_PREALLOCATED;
878   case Attribute::NoUndef:
879     return bitc::ATTR_KIND_NOUNDEF;
880   case Attribute::ByRef:
881     return bitc::ATTR_KIND_BYREF;
882   case Attribute::MustProgress:
883     return bitc::ATTR_KIND_MUSTPROGRESS;
884   case Attribute::PresplitCoroutine:
885     return bitc::ATTR_KIND_PRESPLIT_COROUTINE;
886   case Attribute::Writable:
887     return bitc::ATTR_KIND_WRITABLE;
888   case Attribute::CoroDestroyOnlyWhenComplete:
889     return bitc::ATTR_KIND_CORO_ONLY_DESTROY_WHEN_COMPLETE;
890   case Attribute::CoroElideSafe:
891     return bitc::ATTR_KIND_CORO_ELIDE_SAFE;
892   case Attribute::DeadOnUnwind:
893     return bitc::ATTR_KIND_DEAD_ON_UNWIND;
894   case Attribute::Range:
895     return bitc::ATTR_KIND_RANGE;
896   case Attribute::Initializes:
897     return bitc::ATTR_KIND_INITIALIZES;
898   case Attribute::NoExt:
899     return bitc::ATTR_KIND_NO_EXT;
900   case Attribute::EndAttrKinds:
901     llvm_unreachable("Can not encode end-attribute kinds marker.");
902   case Attribute::None:
903     llvm_unreachable("Can not encode none-attribute.");
904   case Attribute::EmptyKey:
905   case Attribute::TombstoneKey:
906     llvm_unreachable("Trying to encode EmptyKey/TombstoneKey");
907   }
908 
909   llvm_unreachable("Trying to encode unknown attribute");
910 }
911 
912 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
913   if ((int64_t)V >= 0)
914     Vals.push_back(V << 1);
915   else
916     Vals.push_back((-V << 1) | 1);
917 }
918 
919 static void emitWideAPInt(SmallVectorImpl<uint64_t> &Vals, const APInt &A) {
920   // We have an arbitrary precision integer value to write whose
921   // bit width is > 64. However, in canonical unsigned integer
922   // format it is likely that the high bits are going to be zero.
923   // So, we only write the number of active words.
924   unsigned NumWords = A.getActiveWords();
925   const uint64_t *RawData = A.getRawData();
926   for (unsigned i = 0; i < NumWords; i++)
927     emitSignedInt64(Vals, RawData[i]);
928 }
929 
930 static void emitConstantRange(SmallVectorImpl<uint64_t> &Record,
931                               const ConstantRange &CR, bool EmitBitWidth) {
932   unsigned BitWidth = CR.getBitWidth();
933   if (EmitBitWidth)
934     Record.push_back(BitWidth);
935   if (BitWidth > 64) {
936     Record.push_back(CR.getLower().getActiveWords() |
937                      (uint64_t(CR.getUpper().getActiveWords()) << 32));
938     emitWideAPInt(Record, CR.getLower());
939     emitWideAPInt(Record, CR.getUpper());
940   } else {
941     emitSignedInt64(Record, CR.getLower().getSExtValue());
942     emitSignedInt64(Record, CR.getUpper().getSExtValue());
943   }
944 }
945 
946 void ModuleBitcodeWriter::writeAttributeGroupTable() {
947   const std::vector<ValueEnumerator::IndexAndAttrSet> &AttrGrps =
948       VE.getAttributeGroups();
949   if (AttrGrps.empty()) return;
950 
951   Stream.EnterSubblock(bitc::PARAMATTR_GROUP_BLOCK_ID, 3);
952 
953   SmallVector<uint64_t, 64> Record;
954   for (ValueEnumerator::IndexAndAttrSet Pair : AttrGrps) {
955     unsigned AttrListIndex = Pair.first;
956     AttributeSet AS = Pair.second;
957     Record.push_back(VE.getAttributeGroupID(Pair));
958     Record.push_back(AttrListIndex);
959 
960     for (Attribute Attr : AS) {
961       if (Attr.isEnumAttribute()) {
962         Record.push_back(0);
963         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
964       } else if (Attr.isIntAttribute()) {
965         Record.push_back(1);
966         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
967         Record.push_back(Attr.getValueAsInt());
968       } else if (Attr.isStringAttribute()) {
969         StringRef Kind = Attr.getKindAsString();
970         StringRef Val = Attr.getValueAsString();
971 
972         Record.push_back(Val.empty() ? 3 : 4);
973         Record.append(Kind.begin(), Kind.end());
974         Record.push_back(0);
975         if (!Val.empty()) {
976           Record.append(Val.begin(), Val.end());
977           Record.push_back(0);
978         }
979       } else if (Attr.isTypeAttribute()) {
980         Type *Ty = Attr.getValueAsType();
981         Record.push_back(Ty ? 6 : 5);
982         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
983         if (Ty)
984           Record.push_back(VE.getTypeID(Attr.getValueAsType()));
985       } else if (Attr.isConstantRangeAttribute()) {
986         Record.push_back(7);
987         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
988         emitConstantRange(Record, Attr.getValueAsConstantRange(),
989                           /*EmitBitWidth=*/true);
990       } else {
991         assert(Attr.isConstantRangeListAttribute());
992         Record.push_back(8);
993         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
994         ArrayRef<ConstantRange> Val = Attr.getValueAsConstantRangeList();
995         Record.push_back(Val.size());
996         Record.push_back(Val[0].getBitWidth());
997         for (auto &CR : Val)
998           emitConstantRange(Record, CR, /*EmitBitWidth=*/false);
999       }
1000     }
1001 
1002     Stream.EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
1003     Record.clear();
1004   }
1005 
1006   Stream.ExitBlock();
1007 }
1008 
1009 void ModuleBitcodeWriter::writeAttributeTable() {
1010   const std::vector<AttributeList> &Attrs = VE.getAttributeLists();
1011   if (Attrs.empty()) return;
1012 
1013   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
1014 
1015   SmallVector<uint64_t, 64> Record;
1016   for (const AttributeList &AL : Attrs) {
1017     for (unsigned i : AL.indexes()) {
1018       AttributeSet AS = AL.getAttributes(i);
1019       if (AS.hasAttributes())
1020         Record.push_back(VE.getAttributeGroupID({i, AS}));
1021     }
1022 
1023     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
1024     Record.clear();
1025   }
1026 
1027   Stream.ExitBlock();
1028 }
1029 
1030 /// WriteTypeTable - Write out the type table for a module.
1031 void ModuleBitcodeWriter::writeTypeTable() {
1032   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
1033 
1034   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
1035   SmallVector<uint64_t, 64> TypeVals;
1036 
1037   uint64_t NumBits = VE.computeBitsRequiredForTypeIndices();
1038 
1039   // Abbrev for TYPE_CODE_OPAQUE_POINTER.
1040   auto Abbv = std::make_shared<BitCodeAbbrev>();
1041   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_OPAQUE_POINTER));
1042   Abbv->Add(BitCodeAbbrevOp(0)); // Addrspace = 0
1043   unsigned OpaquePtrAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1044 
1045   // Abbrev for TYPE_CODE_FUNCTION.
1046   Abbv = std::make_shared<BitCodeAbbrev>();
1047   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
1048   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
1049   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1050   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
1051   unsigned FunctionAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1052 
1053   // Abbrev for TYPE_CODE_STRUCT_ANON.
1054   Abbv = std::make_shared<BitCodeAbbrev>();
1055   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
1056   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
1057   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1058   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
1059   unsigned StructAnonAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1060 
1061   // Abbrev for TYPE_CODE_STRUCT_NAME.
1062   Abbv = std::make_shared<BitCodeAbbrev>();
1063   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
1064   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1065   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
1066   unsigned StructNameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1067 
1068   // Abbrev for TYPE_CODE_STRUCT_NAMED.
1069   Abbv = std::make_shared<BitCodeAbbrev>();
1070   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
1071   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
1072   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1073   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
1074   unsigned StructNamedAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1075 
1076   // Abbrev for TYPE_CODE_ARRAY.
1077   Abbv = std::make_shared<BitCodeAbbrev>();
1078   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
1079   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
1080   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
1081   unsigned ArrayAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1082 
1083   // Emit an entry count so the reader can reserve space.
1084   TypeVals.push_back(TypeList.size());
1085   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
1086   TypeVals.clear();
1087 
1088   // Loop over all of the types, emitting each in turn.
1089   for (Type *T : TypeList) {
1090     int AbbrevToUse = 0;
1091     unsigned Code = 0;
1092 
1093     switch (T->getTypeID()) {
1094     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;      break;
1095     case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;      break;
1096     case Type::BFloatTyID:    Code = bitc::TYPE_CODE_BFLOAT;    break;
1097     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;     break;
1098     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE;    break;
1099     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80;  break;
1100     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128;     break;
1101     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
1102     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;     break;
1103     case Type::MetadataTyID:
1104       Code = bitc::TYPE_CODE_METADATA;
1105       break;
1106     case Type::X86_AMXTyID:   Code = bitc::TYPE_CODE_X86_AMX;   break;
1107     case Type::TokenTyID:     Code = bitc::TYPE_CODE_TOKEN;     break;
1108     case Type::IntegerTyID:
1109       // INTEGER: [width]
1110       Code = bitc::TYPE_CODE_INTEGER;
1111       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
1112       break;
1113     case Type::PointerTyID: {
1114       PointerType *PTy = cast<PointerType>(T);
1115       unsigned AddressSpace = PTy->getAddressSpace();
1116       // OPAQUE_POINTER: [address space]
1117       Code = bitc::TYPE_CODE_OPAQUE_POINTER;
1118       TypeVals.push_back(AddressSpace);
1119       if (AddressSpace == 0)
1120         AbbrevToUse = OpaquePtrAbbrev;
1121       break;
1122     }
1123     case Type::FunctionTyID: {
1124       FunctionType *FT = cast<FunctionType>(T);
1125       // FUNCTION: [isvararg, retty, paramty x N]
1126       Code = bitc::TYPE_CODE_FUNCTION;
1127       TypeVals.push_back(FT->isVarArg());
1128       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
1129       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
1130         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
1131       AbbrevToUse = FunctionAbbrev;
1132       break;
1133     }
1134     case Type::StructTyID: {
1135       StructType *ST = cast<StructType>(T);
1136       // STRUCT: [ispacked, eltty x N]
1137       TypeVals.push_back(ST->isPacked());
1138       // Output all of the element types.
1139       for (Type *ET : ST->elements())
1140         TypeVals.push_back(VE.getTypeID(ET));
1141 
1142       if (ST->isLiteral()) {
1143         Code = bitc::TYPE_CODE_STRUCT_ANON;
1144         AbbrevToUse = StructAnonAbbrev;
1145       } else {
1146         if (ST->isOpaque()) {
1147           Code = bitc::TYPE_CODE_OPAQUE;
1148         } else {
1149           Code = bitc::TYPE_CODE_STRUCT_NAMED;
1150           AbbrevToUse = StructNamedAbbrev;
1151         }
1152 
1153         // Emit the name if it is present.
1154         if (!ST->getName().empty())
1155           writeStringRecord(Stream, bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
1156                             StructNameAbbrev);
1157       }
1158       break;
1159     }
1160     case Type::ArrayTyID: {
1161       ArrayType *AT = cast<ArrayType>(T);
1162       // ARRAY: [numelts, eltty]
1163       Code = bitc::TYPE_CODE_ARRAY;
1164       TypeVals.push_back(AT->getNumElements());
1165       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
1166       AbbrevToUse = ArrayAbbrev;
1167       break;
1168     }
1169     case Type::FixedVectorTyID:
1170     case Type::ScalableVectorTyID: {
1171       VectorType *VT = cast<VectorType>(T);
1172       // VECTOR [numelts, eltty] or
1173       //        [numelts, eltty, scalable]
1174       Code = bitc::TYPE_CODE_VECTOR;
1175       TypeVals.push_back(VT->getElementCount().getKnownMinValue());
1176       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
1177       if (isa<ScalableVectorType>(VT))
1178         TypeVals.push_back(true);
1179       break;
1180     }
1181     case Type::TargetExtTyID: {
1182       TargetExtType *TET = cast<TargetExtType>(T);
1183       Code = bitc::TYPE_CODE_TARGET_TYPE;
1184       writeStringRecord(Stream, bitc::TYPE_CODE_STRUCT_NAME, TET->getName(),
1185                         StructNameAbbrev);
1186       TypeVals.push_back(TET->getNumTypeParameters());
1187       for (Type *InnerTy : TET->type_params())
1188         TypeVals.push_back(VE.getTypeID(InnerTy));
1189       for (unsigned IntParam : TET->int_params())
1190         TypeVals.push_back(IntParam);
1191       break;
1192     }
1193     case Type::TypedPointerTyID:
1194       llvm_unreachable("Typed pointers cannot be added to IR modules");
1195     }
1196 
1197     // Emit the finished record.
1198     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
1199     TypeVals.clear();
1200   }
1201 
1202   Stream.ExitBlock();
1203 }
1204 
1205 static unsigned getEncodedLinkage(const GlobalValue::LinkageTypes Linkage) {
1206   switch (Linkage) {
1207   case GlobalValue::ExternalLinkage:
1208     return 0;
1209   case GlobalValue::WeakAnyLinkage:
1210     return 16;
1211   case GlobalValue::AppendingLinkage:
1212     return 2;
1213   case GlobalValue::InternalLinkage:
1214     return 3;
1215   case GlobalValue::LinkOnceAnyLinkage:
1216     return 18;
1217   case GlobalValue::ExternalWeakLinkage:
1218     return 7;
1219   case GlobalValue::CommonLinkage:
1220     return 8;
1221   case GlobalValue::PrivateLinkage:
1222     return 9;
1223   case GlobalValue::WeakODRLinkage:
1224     return 17;
1225   case GlobalValue::LinkOnceODRLinkage:
1226     return 19;
1227   case GlobalValue::AvailableExternallyLinkage:
1228     return 12;
1229   }
1230   llvm_unreachable("Invalid linkage");
1231 }
1232 
1233 static unsigned getEncodedLinkage(const GlobalValue &GV) {
1234   return getEncodedLinkage(GV.getLinkage());
1235 }
1236 
1237 static uint64_t getEncodedFFlags(FunctionSummary::FFlags Flags) {
1238   uint64_t RawFlags = 0;
1239   RawFlags |= Flags.ReadNone;
1240   RawFlags |= (Flags.ReadOnly << 1);
1241   RawFlags |= (Flags.NoRecurse << 2);
1242   RawFlags |= (Flags.ReturnDoesNotAlias << 3);
1243   RawFlags |= (Flags.NoInline << 4);
1244   RawFlags |= (Flags.AlwaysInline << 5);
1245   RawFlags |= (Flags.NoUnwind << 6);
1246   RawFlags |= (Flags.MayThrow << 7);
1247   RawFlags |= (Flags.HasUnknownCall << 8);
1248   RawFlags |= (Flags.MustBeUnreachable << 9);
1249   return RawFlags;
1250 }
1251 
1252 // Decode the flags for GlobalValue in the summary. See getDecodedGVSummaryFlags
1253 // in BitcodeReader.cpp.
1254 static uint64_t getEncodedGVSummaryFlags(GlobalValueSummary::GVFlags Flags,
1255                                          bool ImportAsDecl = false) {
1256   uint64_t RawFlags = 0;
1257 
1258   RawFlags |= Flags.NotEligibleToImport; // bool
1259   RawFlags |= (Flags.Live << 1);
1260   RawFlags |= (Flags.DSOLocal << 2);
1261   RawFlags |= (Flags.CanAutoHide << 3);
1262 
1263   // Linkage don't need to be remapped at that time for the summary. Any future
1264   // change to the getEncodedLinkage() function will need to be taken into
1265   // account here as well.
1266   RawFlags = (RawFlags << 4) | Flags.Linkage; // 4 bits
1267 
1268   RawFlags |= (Flags.Visibility << 8); // 2 bits
1269 
1270   unsigned ImportType = Flags.ImportType | ImportAsDecl;
1271   RawFlags |= (ImportType << 10); // 1 bit
1272 
1273   return RawFlags;
1274 }
1275 
1276 static uint64_t getEncodedGVarFlags(GlobalVarSummary::GVarFlags Flags) {
1277   uint64_t RawFlags = Flags.MaybeReadOnly | (Flags.MaybeWriteOnly << 1) |
1278                       (Flags.Constant << 2) | Flags.VCallVisibility << 3;
1279   return RawFlags;
1280 }
1281 
1282 static uint64_t getEncodedHotnessCallEdgeInfo(const CalleeInfo &CI) {
1283   uint64_t RawFlags = 0;
1284 
1285   RawFlags |= CI.Hotness;            // 3 bits
1286   RawFlags |= (CI.HasTailCall << 3); // 1 bit
1287 
1288   return RawFlags;
1289 }
1290 
1291 static uint64_t getEncodedRelBFCallEdgeInfo(const CalleeInfo &CI) {
1292   uint64_t RawFlags = 0;
1293 
1294   RawFlags |= CI.RelBlockFreq; // CalleeInfo::RelBlockFreqBits bits
1295   RawFlags |= (CI.HasTailCall << CalleeInfo::RelBlockFreqBits); // 1 bit
1296 
1297   return RawFlags;
1298 }
1299 
1300 static unsigned getEncodedVisibility(const GlobalValue &GV) {
1301   switch (GV.getVisibility()) {
1302   case GlobalValue::DefaultVisibility:   return 0;
1303   case GlobalValue::HiddenVisibility:    return 1;
1304   case GlobalValue::ProtectedVisibility: return 2;
1305   }
1306   llvm_unreachable("Invalid visibility");
1307 }
1308 
1309 static unsigned getEncodedDLLStorageClass(const GlobalValue &GV) {
1310   switch (GV.getDLLStorageClass()) {
1311   case GlobalValue::DefaultStorageClass:   return 0;
1312   case GlobalValue::DLLImportStorageClass: return 1;
1313   case GlobalValue::DLLExportStorageClass: return 2;
1314   }
1315   llvm_unreachable("Invalid DLL storage class");
1316 }
1317 
1318 static unsigned getEncodedThreadLocalMode(const GlobalValue &GV) {
1319   switch (GV.getThreadLocalMode()) {
1320     case GlobalVariable::NotThreadLocal:         return 0;
1321     case GlobalVariable::GeneralDynamicTLSModel: return 1;
1322     case GlobalVariable::LocalDynamicTLSModel:   return 2;
1323     case GlobalVariable::InitialExecTLSModel:    return 3;
1324     case GlobalVariable::LocalExecTLSModel:      return 4;
1325   }
1326   llvm_unreachable("Invalid TLS model");
1327 }
1328 
1329 static unsigned getEncodedComdatSelectionKind(const Comdat &C) {
1330   switch (C.getSelectionKind()) {
1331   case Comdat::Any:
1332     return bitc::COMDAT_SELECTION_KIND_ANY;
1333   case Comdat::ExactMatch:
1334     return bitc::COMDAT_SELECTION_KIND_EXACT_MATCH;
1335   case Comdat::Largest:
1336     return bitc::COMDAT_SELECTION_KIND_LARGEST;
1337   case Comdat::NoDeduplicate:
1338     return bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES;
1339   case Comdat::SameSize:
1340     return bitc::COMDAT_SELECTION_KIND_SAME_SIZE;
1341   }
1342   llvm_unreachable("Invalid selection kind");
1343 }
1344 
1345 static unsigned getEncodedUnnamedAddr(const GlobalValue &GV) {
1346   switch (GV.getUnnamedAddr()) {
1347   case GlobalValue::UnnamedAddr::None:   return 0;
1348   case GlobalValue::UnnamedAddr::Local:  return 2;
1349   case GlobalValue::UnnamedAddr::Global: return 1;
1350   }
1351   llvm_unreachable("Invalid unnamed_addr");
1352 }
1353 
1354 size_t ModuleBitcodeWriter::addToStrtab(StringRef Str) {
1355   if (GenerateHash)
1356     Hasher.update(Str);
1357   return StrtabBuilder.add(Str);
1358 }
1359 
1360 void ModuleBitcodeWriter::writeComdats() {
1361   SmallVector<unsigned, 64> Vals;
1362   for (const Comdat *C : VE.getComdats()) {
1363     // COMDAT: [strtab offset, strtab size, selection_kind]
1364     Vals.push_back(addToStrtab(C->getName()));
1365     Vals.push_back(C->getName().size());
1366     Vals.push_back(getEncodedComdatSelectionKind(*C));
1367     Stream.EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
1368     Vals.clear();
1369   }
1370 }
1371 
1372 /// Write a record that will eventually hold the word offset of the
1373 /// module-level VST. For now the offset is 0, which will be backpatched
1374 /// after the real VST is written. Saves the bit offset to backpatch.
1375 void ModuleBitcodeWriter::writeValueSymbolTableForwardDecl() {
1376   // Write a placeholder value in for the offset of the real VST,
1377   // which is written after the function blocks so that it can include
1378   // the offset of each function. The placeholder offset will be
1379   // updated when the real VST is written.
1380   auto Abbv = std::make_shared<BitCodeAbbrev>();
1381   Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_VSTOFFSET));
1382   // Blocks are 32-bit aligned, so we can use a 32-bit word offset to
1383   // hold the real VST offset. Must use fixed instead of VBR as we don't
1384   // know how many VBR chunks to reserve ahead of time.
1385   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
1386   unsigned VSTOffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1387 
1388   // Emit the placeholder
1389   uint64_t Vals[] = {bitc::MODULE_CODE_VSTOFFSET, 0};
1390   Stream.EmitRecordWithAbbrev(VSTOffsetAbbrev, Vals);
1391 
1392   // Compute and save the bit offset to the placeholder, which will be
1393   // patched when the real VST is written. We can simply subtract the 32-bit
1394   // fixed size from the current bit number to get the location to backpatch.
1395   VSTOffsetPlaceholder = Stream.GetCurrentBitNo() - 32;
1396 }
1397 
1398 enum StringEncoding { SE_Char6, SE_Fixed7, SE_Fixed8 };
1399 
1400 /// Determine the encoding to use for the given string name and length.
1401 static StringEncoding getStringEncoding(StringRef Str) {
1402   bool isChar6 = true;
1403   for (char C : Str) {
1404     if (isChar6)
1405       isChar6 = BitCodeAbbrevOp::isChar6(C);
1406     if ((unsigned char)C & 128)
1407       // don't bother scanning the rest.
1408       return SE_Fixed8;
1409   }
1410   if (isChar6)
1411     return SE_Char6;
1412   return SE_Fixed7;
1413 }
1414 
1415 static_assert(sizeof(GlobalValue::SanitizerMetadata) <= sizeof(unsigned),
1416               "Sanitizer Metadata is too large for naive serialization.");
1417 static unsigned
1418 serializeSanitizerMetadata(const GlobalValue::SanitizerMetadata &Meta) {
1419   return Meta.NoAddress | (Meta.NoHWAddress << 1) |
1420          (Meta.Memtag << 2) | (Meta.IsDynInit << 3);
1421 }
1422 
1423 /// Emit top-level description of module, including target triple, inline asm,
1424 /// descriptors for global variables, and function prototype info.
1425 /// Returns the bit offset to backpatch with the location of the real VST.
1426 void ModuleBitcodeWriter::writeModuleInfo() {
1427   // Emit various pieces of data attached to a module.
1428   if (!M.getTargetTriple().empty())
1429     writeStringRecord(Stream, bitc::MODULE_CODE_TRIPLE, M.getTargetTriple(),
1430                       0 /*TODO*/);
1431   const std::string &DL = M.getDataLayoutStr();
1432   if (!DL.empty())
1433     writeStringRecord(Stream, bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/);
1434   if (!M.getModuleInlineAsm().empty())
1435     writeStringRecord(Stream, bitc::MODULE_CODE_ASM, M.getModuleInlineAsm(),
1436                       0 /*TODO*/);
1437 
1438   // Emit information about sections and GC, computing how many there are. Also
1439   // compute the maximum alignment value.
1440   std::map<std::string, unsigned> SectionMap;
1441   std::map<std::string, unsigned> GCMap;
1442   MaybeAlign MaxAlignment;
1443   unsigned MaxGlobalType = 0;
1444   const auto UpdateMaxAlignment = [&MaxAlignment](const MaybeAlign A) {
1445     if (A)
1446       MaxAlignment = !MaxAlignment ? *A : std::max(*MaxAlignment, *A);
1447   };
1448   for (const GlobalVariable &GV : M.globals()) {
1449     UpdateMaxAlignment(GV.getAlign());
1450     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getValueType()));
1451     if (GV.hasSection()) {
1452       // Give section names unique ID's.
1453       unsigned &Entry = SectionMap[std::string(GV.getSection())];
1454       if (!Entry) {
1455         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
1456                           0 /*TODO*/);
1457         Entry = SectionMap.size();
1458       }
1459     }
1460   }
1461   for (const Function &F : M) {
1462     UpdateMaxAlignment(F.getAlign());
1463     if (F.hasSection()) {
1464       // Give section names unique ID's.
1465       unsigned &Entry = SectionMap[std::string(F.getSection())];
1466       if (!Entry) {
1467         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
1468                           0 /*TODO*/);
1469         Entry = SectionMap.size();
1470       }
1471     }
1472     if (F.hasGC()) {
1473       // Same for GC names.
1474       unsigned &Entry = GCMap[F.getGC()];
1475       if (!Entry) {
1476         writeStringRecord(Stream, bitc::MODULE_CODE_GCNAME, F.getGC(),
1477                           0 /*TODO*/);
1478         Entry = GCMap.size();
1479       }
1480     }
1481   }
1482 
1483   // Emit abbrev for globals, now that we know # sections and max alignment.
1484   unsigned SimpleGVarAbbrev = 0;
1485   if (!M.global_empty()) {
1486     // Add an abbrev for common globals with no visibility or thread localness.
1487     auto Abbv = std::make_shared<BitCodeAbbrev>();
1488     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
1489     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1490     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1491     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1492                               Log2_32_Ceil(MaxGlobalType+1)));
1493     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddrSpace << 2
1494                                                            //| explicitType << 1
1495                                                            //| constant
1496     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Initializer.
1497     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // Linkage.
1498     if (!MaxAlignment)                                     // Alignment.
1499       Abbv->Add(BitCodeAbbrevOp(0));
1500     else {
1501       unsigned MaxEncAlignment = getEncodedAlign(MaxAlignment);
1502       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1503                                Log2_32_Ceil(MaxEncAlignment+1)));
1504     }
1505     if (SectionMap.empty())                                    // Section.
1506       Abbv->Add(BitCodeAbbrevOp(0));
1507     else
1508       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1509                                Log2_32_Ceil(SectionMap.size()+1)));
1510     // Don't bother emitting vis + thread local.
1511     SimpleGVarAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1512   }
1513 
1514   SmallVector<unsigned, 64> Vals;
1515   // Emit the module's source file name.
1516   {
1517     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
1518     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
1519     if (Bits == SE_Char6)
1520       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
1521     else if (Bits == SE_Fixed7)
1522       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
1523 
1524     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
1525     auto Abbv = std::make_shared<BitCodeAbbrev>();
1526     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
1527     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1528     Abbv->Add(AbbrevOpToUse);
1529     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1530 
1531     for (const auto P : M.getSourceFileName())
1532       Vals.push_back((unsigned char)P);
1533 
1534     // Emit the finished record.
1535     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
1536     Vals.clear();
1537   }
1538 
1539   // Emit the global variable information.
1540   for (const GlobalVariable &GV : M.globals()) {
1541     unsigned AbbrevToUse = 0;
1542 
1543     // GLOBALVAR: [strtab offset, strtab size, type, isconst, initid,
1544     //             linkage, alignment, section, visibility, threadlocal,
1545     //             unnamed_addr, externally_initialized, dllstorageclass,
1546     //             comdat, attributes, DSO_Local, GlobalSanitizer, code_model]
1547     Vals.push_back(addToStrtab(GV.getName()));
1548     Vals.push_back(GV.getName().size());
1549     Vals.push_back(VE.getTypeID(GV.getValueType()));
1550     Vals.push_back(GV.getType()->getAddressSpace() << 2 | 2 | GV.isConstant());
1551     Vals.push_back(GV.isDeclaration() ? 0 :
1552                    (VE.getValueID(GV.getInitializer()) + 1));
1553     Vals.push_back(getEncodedLinkage(GV));
1554     Vals.push_back(getEncodedAlign(GV.getAlign()));
1555     Vals.push_back(GV.hasSection() ? SectionMap[std::string(GV.getSection())]
1556                                    : 0);
1557     if (GV.isThreadLocal() ||
1558         GV.getVisibility() != GlobalValue::DefaultVisibility ||
1559         GV.getUnnamedAddr() != GlobalValue::UnnamedAddr::None ||
1560         GV.isExternallyInitialized() ||
1561         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
1562         GV.hasComdat() || GV.hasAttributes() || GV.isDSOLocal() ||
1563         GV.hasPartition() || GV.hasSanitizerMetadata() || GV.getCodeModel()) {
1564       Vals.push_back(getEncodedVisibility(GV));
1565       Vals.push_back(getEncodedThreadLocalMode(GV));
1566       Vals.push_back(getEncodedUnnamedAddr(GV));
1567       Vals.push_back(GV.isExternallyInitialized());
1568       Vals.push_back(getEncodedDLLStorageClass(GV));
1569       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
1570 
1571       auto AL = GV.getAttributesAsList(AttributeList::FunctionIndex);
1572       Vals.push_back(VE.getAttributeListID(AL));
1573 
1574       Vals.push_back(GV.isDSOLocal());
1575       Vals.push_back(addToStrtab(GV.getPartition()));
1576       Vals.push_back(GV.getPartition().size());
1577 
1578       Vals.push_back((GV.hasSanitizerMetadata() ? serializeSanitizerMetadata(
1579                                                       GV.getSanitizerMetadata())
1580                                                 : 0));
1581       Vals.push_back(GV.getCodeModelRaw());
1582     } else {
1583       AbbrevToUse = SimpleGVarAbbrev;
1584     }
1585 
1586     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
1587     Vals.clear();
1588   }
1589 
1590   // Emit the function proto information.
1591   for (const Function &F : M) {
1592     // FUNCTION:  [strtab offset, strtab size, type, callingconv, isproto,
1593     //             linkage, paramattrs, alignment, section, visibility, gc,
1594     //             unnamed_addr, prologuedata, dllstorageclass, comdat,
1595     //             prefixdata, personalityfn, DSO_Local, addrspace]
1596     Vals.push_back(addToStrtab(F.getName()));
1597     Vals.push_back(F.getName().size());
1598     Vals.push_back(VE.getTypeID(F.getFunctionType()));
1599     Vals.push_back(F.getCallingConv());
1600     Vals.push_back(F.isDeclaration());
1601     Vals.push_back(getEncodedLinkage(F));
1602     Vals.push_back(VE.getAttributeListID(F.getAttributes()));
1603     Vals.push_back(getEncodedAlign(F.getAlign()));
1604     Vals.push_back(F.hasSection() ? SectionMap[std::string(F.getSection())]
1605                                   : 0);
1606     Vals.push_back(getEncodedVisibility(F));
1607     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
1608     Vals.push_back(getEncodedUnnamedAddr(F));
1609     Vals.push_back(F.hasPrologueData() ? (VE.getValueID(F.getPrologueData()) + 1)
1610                                        : 0);
1611     Vals.push_back(getEncodedDLLStorageClass(F));
1612     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
1613     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
1614                                      : 0);
1615     Vals.push_back(
1616         F.hasPersonalityFn() ? (VE.getValueID(F.getPersonalityFn()) + 1) : 0);
1617 
1618     Vals.push_back(F.isDSOLocal());
1619     Vals.push_back(F.getAddressSpace());
1620     Vals.push_back(addToStrtab(F.getPartition()));
1621     Vals.push_back(F.getPartition().size());
1622 
1623     unsigned AbbrevToUse = 0;
1624     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
1625     Vals.clear();
1626   }
1627 
1628   // Emit the alias information.
1629   for (const GlobalAlias &A : M.aliases()) {
1630     // ALIAS: [strtab offset, strtab size, alias type, aliasee val#, linkage,
1631     //         visibility, dllstorageclass, threadlocal, unnamed_addr,
1632     //         DSO_Local]
1633     Vals.push_back(addToStrtab(A.getName()));
1634     Vals.push_back(A.getName().size());
1635     Vals.push_back(VE.getTypeID(A.getValueType()));
1636     Vals.push_back(A.getType()->getAddressSpace());
1637     Vals.push_back(VE.getValueID(A.getAliasee()));
1638     Vals.push_back(getEncodedLinkage(A));
1639     Vals.push_back(getEncodedVisibility(A));
1640     Vals.push_back(getEncodedDLLStorageClass(A));
1641     Vals.push_back(getEncodedThreadLocalMode(A));
1642     Vals.push_back(getEncodedUnnamedAddr(A));
1643     Vals.push_back(A.isDSOLocal());
1644     Vals.push_back(addToStrtab(A.getPartition()));
1645     Vals.push_back(A.getPartition().size());
1646 
1647     unsigned AbbrevToUse = 0;
1648     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
1649     Vals.clear();
1650   }
1651 
1652   // Emit the ifunc information.
1653   for (const GlobalIFunc &I : M.ifuncs()) {
1654     // IFUNC: [strtab offset, strtab size, ifunc type, address space, resolver
1655     //         val#, linkage, visibility, DSO_Local]
1656     Vals.push_back(addToStrtab(I.getName()));
1657     Vals.push_back(I.getName().size());
1658     Vals.push_back(VE.getTypeID(I.getValueType()));
1659     Vals.push_back(I.getType()->getAddressSpace());
1660     Vals.push_back(VE.getValueID(I.getResolver()));
1661     Vals.push_back(getEncodedLinkage(I));
1662     Vals.push_back(getEncodedVisibility(I));
1663     Vals.push_back(I.isDSOLocal());
1664     Vals.push_back(addToStrtab(I.getPartition()));
1665     Vals.push_back(I.getPartition().size());
1666     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
1667     Vals.clear();
1668   }
1669 
1670   writeValueSymbolTableForwardDecl();
1671 }
1672 
1673 static uint64_t getOptimizationFlags(const Value *V) {
1674   uint64_t Flags = 0;
1675 
1676   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
1677     if (OBO->hasNoSignedWrap())
1678       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
1679     if (OBO->hasNoUnsignedWrap())
1680       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
1681   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
1682     if (PEO->isExact())
1683       Flags |= 1 << bitc::PEO_EXACT;
1684   } else if (const auto *PDI = dyn_cast<PossiblyDisjointInst>(V)) {
1685     if (PDI->isDisjoint())
1686       Flags |= 1 << bitc::PDI_DISJOINT;
1687   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
1688     if (FPMO->hasAllowReassoc())
1689       Flags |= bitc::AllowReassoc;
1690     if (FPMO->hasNoNaNs())
1691       Flags |= bitc::NoNaNs;
1692     if (FPMO->hasNoInfs())
1693       Flags |= bitc::NoInfs;
1694     if (FPMO->hasNoSignedZeros())
1695       Flags |= bitc::NoSignedZeros;
1696     if (FPMO->hasAllowReciprocal())
1697       Flags |= bitc::AllowReciprocal;
1698     if (FPMO->hasAllowContract())
1699       Flags |= bitc::AllowContract;
1700     if (FPMO->hasApproxFunc())
1701       Flags |= bitc::ApproxFunc;
1702   } else if (const auto *NNI = dyn_cast<PossiblyNonNegInst>(V)) {
1703     if (NNI->hasNonNeg())
1704       Flags |= 1 << bitc::PNNI_NON_NEG;
1705   } else if (const auto *TI = dyn_cast<TruncInst>(V)) {
1706     if (TI->hasNoSignedWrap())
1707       Flags |= 1 << bitc::TIO_NO_SIGNED_WRAP;
1708     if (TI->hasNoUnsignedWrap())
1709       Flags |= 1 << bitc::TIO_NO_UNSIGNED_WRAP;
1710   } else if (const auto *GEP = dyn_cast<GEPOperator>(V)) {
1711     if (GEP->isInBounds())
1712       Flags |= 1 << bitc::GEP_INBOUNDS;
1713     if (GEP->hasNoUnsignedSignedWrap())
1714       Flags |= 1 << bitc::GEP_NUSW;
1715     if (GEP->hasNoUnsignedWrap())
1716       Flags |= 1 << bitc::GEP_NUW;
1717   }
1718 
1719   return Flags;
1720 }
1721 
1722 void ModuleBitcodeWriter::writeValueAsMetadata(
1723     const ValueAsMetadata *MD, SmallVectorImpl<uint64_t> &Record) {
1724   // Mimic an MDNode with a value as one operand.
1725   Value *V = MD->getValue();
1726   Record.push_back(VE.getTypeID(V->getType()));
1727   Record.push_back(VE.getValueID(V));
1728   Stream.EmitRecord(bitc::METADATA_VALUE, Record, 0);
1729   Record.clear();
1730 }
1731 
1732 void ModuleBitcodeWriter::writeMDTuple(const MDTuple *N,
1733                                        SmallVectorImpl<uint64_t> &Record,
1734                                        unsigned Abbrev) {
1735   for (const MDOperand &MDO : N->operands()) {
1736     Metadata *MD = MDO;
1737     assert(!(MD && isa<LocalAsMetadata>(MD)) &&
1738            "Unexpected function-local metadata");
1739     Record.push_back(VE.getMetadataOrNullID(MD));
1740   }
1741   Stream.EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
1742                                     : bitc::METADATA_NODE,
1743                     Record, Abbrev);
1744   Record.clear();
1745 }
1746 
1747 unsigned ModuleBitcodeWriter::createDILocationAbbrev() {
1748   // Assume the column is usually under 128, and always output the inlined-at
1749   // location (it's never more expensive than building an array size 1).
1750   auto Abbv = std::make_shared<BitCodeAbbrev>();
1751   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
1752   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1753   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1754   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1755   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1756   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1757   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1758   return Stream.EmitAbbrev(std::move(Abbv));
1759 }
1760 
1761 void ModuleBitcodeWriter::writeDILocation(const DILocation *N,
1762                                           SmallVectorImpl<uint64_t> &Record,
1763                                           unsigned &Abbrev) {
1764   if (!Abbrev)
1765     Abbrev = createDILocationAbbrev();
1766 
1767   Record.push_back(N->isDistinct());
1768   Record.push_back(N->getLine());
1769   Record.push_back(N->getColumn());
1770   Record.push_back(VE.getMetadataID(N->getScope()));
1771   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
1772   Record.push_back(N->isImplicitCode());
1773 
1774   Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
1775   Record.clear();
1776 }
1777 
1778 unsigned ModuleBitcodeWriter::createGenericDINodeAbbrev() {
1779   // Assume the column is usually under 128, and always output the inlined-at
1780   // location (it's never more expensive than building an array size 1).
1781   auto Abbv = std::make_shared<BitCodeAbbrev>();
1782   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
1783   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1784   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1785   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1786   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1787   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1788   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1789   return Stream.EmitAbbrev(std::move(Abbv));
1790 }
1791 
1792 void ModuleBitcodeWriter::writeGenericDINode(const GenericDINode *N,
1793                                              SmallVectorImpl<uint64_t> &Record,
1794                                              unsigned &Abbrev) {
1795   if (!Abbrev)
1796     Abbrev = createGenericDINodeAbbrev();
1797 
1798   Record.push_back(N->isDistinct());
1799   Record.push_back(N->getTag());
1800   Record.push_back(0); // Per-tag version field; unused for now.
1801 
1802   for (auto &I : N->operands())
1803     Record.push_back(VE.getMetadataOrNullID(I));
1804 
1805   Stream.EmitRecord(bitc::METADATA_GENERIC_DEBUG, Record, Abbrev);
1806   Record.clear();
1807 }
1808 
1809 void ModuleBitcodeWriter::writeDISubrange(const DISubrange *N,
1810                                           SmallVectorImpl<uint64_t> &Record,
1811                                           unsigned Abbrev) {
1812   const uint64_t Version = 2 << 1;
1813   Record.push_back((uint64_t)N->isDistinct() | Version);
1814   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1815   Record.push_back(VE.getMetadataOrNullID(N->getRawLowerBound()));
1816   Record.push_back(VE.getMetadataOrNullID(N->getRawUpperBound()));
1817   Record.push_back(VE.getMetadataOrNullID(N->getRawStride()));
1818 
1819   Stream.EmitRecord(bitc::METADATA_SUBRANGE, Record, Abbrev);
1820   Record.clear();
1821 }
1822 
1823 void ModuleBitcodeWriter::writeDIGenericSubrange(
1824     const DIGenericSubrange *N, SmallVectorImpl<uint64_t> &Record,
1825     unsigned Abbrev) {
1826   Record.push_back((uint64_t)N->isDistinct());
1827   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1828   Record.push_back(VE.getMetadataOrNullID(N->getRawLowerBound()));
1829   Record.push_back(VE.getMetadataOrNullID(N->getRawUpperBound()));
1830   Record.push_back(VE.getMetadataOrNullID(N->getRawStride()));
1831 
1832   Stream.EmitRecord(bitc::METADATA_GENERIC_SUBRANGE, Record, Abbrev);
1833   Record.clear();
1834 }
1835 
1836 void ModuleBitcodeWriter::writeDIEnumerator(const DIEnumerator *N,
1837                                             SmallVectorImpl<uint64_t> &Record,
1838                                             unsigned Abbrev) {
1839   const uint64_t IsBigInt = 1 << 2;
1840   Record.push_back(IsBigInt | (N->isUnsigned() << 1) | N->isDistinct());
1841   Record.push_back(N->getValue().getBitWidth());
1842   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1843   emitWideAPInt(Record, N->getValue());
1844 
1845   Stream.EmitRecord(bitc::METADATA_ENUMERATOR, Record, Abbrev);
1846   Record.clear();
1847 }
1848 
1849 void ModuleBitcodeWriter::writeDIBasicType(const DIBasicType *N,
1850                                            SmallVectorImpl<uint64_t> &Record,
1851                                            unsigned Abbrev) {
1852   Record.push_back(N->isDistinct());
1853   Record.push_back(N->getTag());
1854   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1855   Record.push_back(N->getSizeInBits());
1856   Record.push_back(N->getAlignInBits());
1857   Record.push_back(N->getEncoding());
1858   Record.push_back(N->getFlags());
1859 
1860   Stream.EmitRecord(bitc::METADATA_BASIC_TYPE, Record, Abbrev);
1861   Record.clear();
1862 }
1863 
1864 void ModuleBitcodeWriter::writeDIStringType(const DIStringType *N,
1865                                             SmallVectorImpl<uint64_t> &Record,
1866                                             unsigned Abbrev) {
1867   Record.push_back(N->isDistinct());
1868   Record.push_back(N->getTag());
1869   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1870   Record.push_back(VE.getMetadataOrNullID(N->getStringLength()));
1871   Record.push_back(VE.getMetadataOrNullID(N->getStringLengthExp()));
1872   Record.push_back(VE.getMetadataOrNullID(N->getStringLocationExp()));
1873   Record.push_back(N->getSizeInBits());
1874   Record.push_back(N->getAlignInBits());
1875   Record.push_back(N->getEncoding());
1876 
1877   Stream.EmitRecord(bitc::METADATA_STRING_TYPE, Record, Abbrev);
1878   Record.clear();
1879 }
1880 
1881 void ModuleBitcodeWriter::writeDIDerivedType(const DIDerivedType *N,
1882                                              SmallVectorImpl<uint64_t> &Record,
1883                                              unsigned Abbrev) {
1884   Record.push_back(N->isDistinct());
1885   Record.push_back(N->getTag());
1886   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1887   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1888   Record.push_back(N->getLine());
1889   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1890   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1891   Record.push_back(N->getSizeInBits());
1892   Record.push_back(N->getAlignInBits());
1893   Record.push_back(N->getOffsetInBits());
1894   Record.push_back(N->getFlags());
1895   Record.push_back(VE.getMetadataOrNullID(N->getExtraData()));
1896 
1897   // DWARF address space is encoded as N->getDWARFAddressSpace() + 1. 0 means
1898   // that there is no DWARF address space associated with DIDerivedType.
1899   if (const auto &DWARFAddressSpace = N->getDWARFAddressSpace())
1900     Record.push_back(*DWARFAddressSpace + 1);
1901   else
1902     Record.push_back(0);
1903 
1904   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1905 
1906   if (auto PtrAuthData = N->getPtrAuthData())
1907     Record.push_back(PtrAuthData->RawData);
1908   else
1909     Record.push_back(0);
1910 
1911   Stream.EmitRecord(bitc::METADATA_DERIVED_TYPE, Record, Abbrev);
1912   Record.clear();
1913 }
1914 
1915 void ModuleBitcodeWriter::writeDICompositeType(
1916     const DICompositeType *N, SmallVectorImpl<uint64_t> &Record,
1917     unsigned Abbrev) {
1918   const unsigned IsNotUsedInOldTypeRef = 0x2;
1919   Record.push_back(IsNotUsedInOldTypeRef | (unsigned)N->isDistinct());
1920   Record.push_back(N->getTag());
1921   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1922   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1923   Record.push_back(N->getLine());
1924   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1925   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1926   Record.push_back(N->getSizeInBits());
1927   Record.push_back(N->getAlignInBits());
1928   Record.push_back(N->getOffsetInBits());
1929   Record.push_back(N->getFlags());
1930   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1931   Record.push_back(N->getRuntimeLang());
1932   Record.push_back(VE.getMetadataOrNullID(N->getVTableHolder()));
1933   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1934   Record.push_back(VE.getMetadataOrNullID(N->getRawIdentifier()));
1935   Record.push_back(VE.getMetadataOrNullID(N->getDiscriminator()));
1936   Record.push_back(VE.getMetadataOrNullID(N->getRawDataLocation()));
1937   Record.push_back(VE.getMetadataOrNullID(N->getRawAssociated()));
1938   Record.push_back(VE.getMetadataOrNullID(N->getRawAllocated()));
1939   Record.push_back(VE.getMetadataOrNullID(N->getRawRank()));
1940   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1941 
1942   Stream.EmitRecord(bitc::METADATA_COMPOSITE_TYPE, Record, Abbrev);
1943   Record.clear();
1944 }
1945 
1946 void ModuleBitcodeWriter::writeDISubroutineType(
1947     const DISubroutineType *N, SmallVectorImpl<uint64_t> &Record,
1948     unsigned Abbrev) {
1949   const unsigned HasNoOldTypeRefs = 0x2;
1950   Record.push_back(HasNoOldTypeRefs | (unsigned)N->isDistinct());
1951   Record.push_back(N->getFlags());
1952   Record.push_back(VE.getMetadataOrNullID(N->getTypeArray().get()));
1953   Record.push_back(N->getCC());
1954 
1955   Stream.EmitRecord(bitc::METADATA_SUBROUTINE_TYPE, Record, Abbrev);
1956   Record.clear();
1957 }
1958 
1959 void ModuleBitcodeWriter::writeDIFile(const DIFile *N,
1960                                       SmallVectorImpl<uint64_t> &Record,
1961                                       unsigned Abbrev) {
1962   Record.push_back(N->isDistinct());
1963   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
1964   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
1965   if (N->getRawChecksum()) {
1966     Record.push_back(N->getRawChecksum()->Kind);
1967     Record.push_back(VE.getMetadataOrNullID(N->getRawChecksum()->Value));
1968   } else {
1969     // Maintain backwards compatibility with the old internal representation of
1970     // CSK_None in ChecksumKind by writing nulls here when Checksum is None.
1971     Record.push_back(0);
1972     Record.push_back(VE.getMetadataOrNullID(nullptr));
1973   }
1974   auto Source = N->getRawSource();
1975   if (Source)
1976     Record.push_back(VE.getMetadataOrNullID(Source));
1977 
1978   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
1979   Record.clear();
1980 }
1981 
1982 void ModuleBitcodeWriter::writeDICompileUnit(const DICompileUnit *N,
1983                                              SmallVectorImpl<uint64_t> &Record,
1984                                              unsigned Abbrev) {
1985   assert(N->isDistinct() && "Expected distinct compile units");
1986   Record.push_back(/* IsDistinct */ true);
1987   Record.push_back(N->getSourceLanguage());
1988   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1989   Record.push_back(VE.getMetadataOrNullID(N->getRawProducer()));
1990   Record.push_back(N->isOptimized());
1991   Record.push_back(VE.getMetadataOrNullID(N->getRawFlags()));
1992   Record.push_back(N->getRuntimeVersion());
1993   Record.push_back(VE.getMetadataOrNullID(N->getRawSplitDebugFilename()));
1994   Record.push_back(N->getEmissionKind());
1995   Record.push_back(VE.getMetadataOrNullID(N->getEnumTypes().get()));
1996   Record.push_back(VE.getMetadataOrNullID(N->getRetainedTypes().get()));
1997   Record.push_back(/* subprograms */ 0);
1998   Record.push_back(VE.getMetadataOrNullID(N->getGlobalVariables().get()));
1999   Record.push_back(VE.getMetadataOrNullID(N->getImportedEntities().get()));
2000   Record.push_back(N->getDWOId());
2001   Record.push_back(VE.getMetadataOrNullID(N->getMacros().get()));
2002   Record.push_back(N->getSplitDebugInlining());
2003   Record.push_back(N->getDebugInfoForProfiling());
2004   Record.push_back((unsigned)N->getNameTableKind());
2005   Record.push_back(N->getRangesBaseAddress());
2006   Record.push_back(VE.getMetadataOrNullID(N->getRawSysRoot()));
2007   Record.push_back(VE.getMetadataOrNullID(N->getRawSDK()));
2008 
2009   Stream.EmitRecord(bitc::METADATA_COMPILE_UNIT, Record, Abbrev);
2010   Record.clear();
2011 }
2012 
2013 void ModuleBitcodeWriter::writeDISubprogram(const DISubprogram *N,
2014                                             SmallVectorImpl<uint64_t> &Record,
2015                                             unsigned Abbrev) {
2016   const uint64_t HasUnitFlag = 1 << 1;
2017   const uint64_t HasSPFlagsFlag = 1 << 2;
2018   Record.push_back(uint64_t(N->isDistinct()) | HasUnitFlag | HasSPFlagsFlag);
2019   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2020   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2021   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
2022   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2023   Record.push_back(N->getLine());
2024   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2025   Record.push_back(N->getScopeLine());
2026   Record.push_back(VE.getMetadataOrNullID(N->getContainingType()));
2027   Record.push_back(N->getSPFlags());
2028   Record.push_back(N->getVirtualIndex());
2029   Record.push_back(N->getFlags());
2030   Record.push_back(VE.getMetadataOrNullID(N->getRawUnit()));
2031   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
2032   Record.push_back(VE.getMetadataOrNullID(N->getDeclaration()));
2033   Record.push_back(VE.getMetadataOrNullID(N->getRetainedNodes().get()));
2034   Record.push_back(N->getThisAdjustment());
2035   Record.push_back(VE.getMetadataOrNullID(N->getThrownTypes().get()));
2036   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
2037   Record.push_back(VE.getMetadataOrNullID(N->getRawTargetFuncName()));
2038 
2039   Stream.EmitRecord(bitc::METADATA_SUBPROGRAM, Record, Abbrev);
2040   Record.clear();
2041 }
2042 
2043 void ModuleBitcodeWriter::writeDILexicalBlock(const DILexicalBlock *N,
2044                                               SmallVectorImpl<uint64_t> &Record,
2045                                               unsigned Abbrev) {
2046   Record.push_back(N->isDistinct());
2047   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2048   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2049   Record.push_back(N->getLine());
2050   Record.push_back(N->getColumn());
2051 
2052   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK, Record, Abbrev);
2053   Record.clear();
2054 }
2055 
2056 void ModuleBitcodeWriter::writeDILexicalBlockFile(
2057     const DILexicalBlockFile *N, SmallVectorImpl<uint64_t> &Record,
2058     unsigned Abbrev) {
2059   Record.push_back(N->isDistinct());
2060   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2061   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2062   Record.push_back(N->getDiscriminator());
2063 
2064   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK_FILE, Record, Abbrev);
2065   Record.clear();
2066 }
2067 
2068 void ModuleBitcodeWriter::writeDICommonBlock(const DICommonBlock *N,
2069                                              SmallVectorImpl<uint64_t> &Record,
2070                                              unsigned Abbrev) {
2071   Record.push_back(N->isDistinct());
2072   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2073   Record.push_back(VE.getMetadataOrNullID(N->getDecl()));
2074   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2075   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2076   Record.push_back(N->getLineNo());
2077 
2078   Stream.EmitRecord(bitc::METADATA_COMMON_BLOCK, Record, Abbrev);
2079   Record.clear();
2080 }
2081 
2082 void ModuleBitcodeWriter::writeDINamespace(const DINamespace *N,
2083                                            SmallVectorImpl<uint64_t> &Record,
2084                                            unsigned Abbrev) {
2085   Record.push_back(N->isDistinct() | N->getExportSymbols() << 1);
2086   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2087   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2088 
2089   Stream.EmitRecord(bitc::METADATA_NAMESPACE, Record, Abbrev);
2090   Record.clear();
2091 }
2092 
2093 void ModuleBitcodeWriter::writeDIMacro(const DIMacro *N,
2094                                        SmallVectorImpl<uint64_t> &Record,
2095                                        unsigned Abbrev) {
2096   Record.push_back(N->isDistinct());
2097   Record.push_back(N->getMacinfoType());
2098   Record.push_back(N->getLine());
2099   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2100   Record.push_back(VE.getMetadataOrNullID(N->getRawValue()));
2101 
2102   Stream.EmitRecord(bitc::METADATA_MACRO, Record, Abbrev);
2103   Record.clear();
2104 }
2105 
2106 void ModuleBitcodeWriter::writeDIMacroFile(const DIMacroFile *N,
2107                                            SmallVectorImpl<uint64_t> &Record,
2108                                            unsigned Abbrev) {
2109   Record.push_back(N->isDistinct());
2110   Record.push_back(N->getMacinfoType());
2111   Record.push_back(N->getLine());
2112   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2113   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
2114 
2115   Stream.EmitRecord(bitc::METADATA_MACRO_FILE, Record, Abbrev);
2116   Record.clear();
2117 }
2118 
2119 void ModuleBitcodeWriter::writeDIArgList(const DIArgList *N,
2120                                          SmallVectorImpl<uint64_t> &Record) {
2121   Record.reserve(N->getArgs().size());
2122   for (ValueAsMetadata *MD : N->getArgs())
2123     Record.push_back(VE.getMetadataID(MD));
2124 
2125   Stream.EmitRecord(bitc::METADATA_ARG_LIST, Record);
2126   Record.clear();
2127 }
2128 
2129 void ModuleBitcodeWriter::writeDIModule(const DIModule *N,
2130                                         SmallVectorImpl<uint64_t> &Record,
2131                                         unsigned Abbrev) {
2132   Record.push_back(N->isDistinct());
2133   for (auto &I : N->operands())
2134     Record.push_back(VE.getMetadataOrNullID(I));
2135   Record.push_back(N->getLineNo());
2136   Record.push_back(N->getIsDecl());
2137 
2138   Stream.EmitRecord(bitc::METADATA_MODULE, Record, Abbrev);
2139   Record.clear();
2140 }
2141 
2142 void ModuleBitcodeWriter::writeDIAssignID(const DIAssignID *N,
2143                                           SmallVectorImpl<uint64_t> &Record,
2144                                           unsigned Abbrev) {
2145   // There are no arguments for this metadata type.
2146   Record.push_back(N->isDistinct());
2147   Stream.EmitRecord(bitc::METADATA_ASSIGN_ID, Record, Abbrev);
2148   Record.clear();
2149 }
2150 
2151 void ModuleBitcodeWriter::writeDITemplateTypeParameter(
2152     const DITemplateTypeParameter *N, SmallVectorImpl<uint64_t> &Record,
2153     unsigned Abbrev) {
2154   Record.push_back(N->isDistinct());
2155   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2156   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2157   Record.push_back(N->isDefault());
2158 
2159   Stream.EmitRecord(bitc::METADATA_TEMPLATE_TYPE, Record, Abbrev);
2160   Record.clear();
2161 }
2162 
2163 void ModuleBitcodeWriter::writeDITemplateValueParameter(
2164     const DITemplateValueParameter *N, SmallVectorImpl<uint64_t> &Record,
2165     unsigned Abbrev) {
2166   Record.push_back(N->isDistinct());
2167   Record.push_back(N->getTag());
2168   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2169   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2170   Record.push_back(N->isDefault());
2171   Record.push_back(VE.getMetadataOrNullID(N->getValue()));
2172 
2173   Stream.EmitRecord(bitc::METADATA_TEMPLATE_VALUE, Record, Abbrev);
2174   Record.clear();
2175 }
2176 
2177 void ModuleBitcodeWriter::writeDIGlobalVariable(
2178     const DIGlobalVariable *N, SmallVectorImpl<uint64_t> &Record,
2179     unsigned Abbrev) {
2180   const uint64_t Version = 2 << 1;
2181   Record.push_back((uint64_t)N->isDistinct() | Version);
2182   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2183   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2184   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
2185   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2186   Record.push_back(N->getLine());
2187   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2188   Record.push_back(N->isLocalToUnit());
2189   Record.push_back(N->isDefinition());
2190   Record.push_back(VE.getMetadataOrNullID(N->getStaticDataMemberDeclaration()));
2191   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams()));
2192   Record.push_back(N->getAlignInBits());
2193   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
2194 
2195   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR, Record, Abbrev);
2196   Record.clear();
2197 }
2198 
2199 void ModuleBitcodeWriter::writeDILocalVariable(
2200     const DILocalVariable *N, SmallVectorImpl<uint64_t> &Record,
2201     unsigned Abbrev) {
2202   // In order to support all possible bitcode formats in BitcodeReader we need
2203   // to distinguish the following cases:
2204   // 1) Record has no artificial tag (Record[1]),
2205   //   has no obsolete inlinedAt field (Record[9]).
2206   //   In this case Record size will be 8, HasAlignment flag is false.
2207   // 2) Record has artificial tag (Record[1]),
2208   //   has no obsolete inlignedAt field (Record[9]).
2209   //   In this case Record size will be 9, HasAlignment flag is false.
2210   // 3) Record has both artificial tag (Record[1]) and
2211   //   obsolete inlignedAt field (Record[9]).
2212   //   In this case Record size will be 10, HasAlignment flag is false.
2213   // 4) Record has neither artificial tag, nor inlignedAt field, but
2214   //   HasAlignment flag is true and Record[8] contains alignment value.
2215   const uint64_t HasAlignmentFlag = 1 << 1;
2216   Record.push_back((uint64_t)N->isDistinct() | HasAlignmentFlag);
2217   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2218   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2219   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2220   Record.push_back(N->getLine());
2221   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2222   Record.push_back(N->getArg());
2223   Record.push_back(N->getFlags());
2224   Record.push_back(N->getAlignInBits());
2225   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
2226 
2227   Stream.EmitRecord(bitc::METADATA_LOCAL_VAR, Record, Abbrev);
2228   Record.clear();
2229 }
2230 
2231 void ModuleBitcodeWriter::writeDILabel(
2232     const DILabel *N, SmallVectorImpl<uint64_t> &Record,
2233     unsigned Abbrev) {
2234   Record.push_back((uint64_t)N->isDistinct());
2235   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2236   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2237   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2238   Record.push_back(N->getLine());
2239 
2240   Stream.EmitRecord(bitc::METADATA_LABEL, Record, Abbrev);
2241   Record.clear();
2242 }
2243 
2244 void ModuleBitcodeWriter::writeDIExpression(const DIExpression *N,
2245                                             SmallVectorImpl<uint64_t> &Record,
2246                                             unsigned Abbrev) {
2247   Record.reserve(N->getElements().size() + 1);
2248   const uint64_t Version = 3 << 1;
2249   Record.push_back((uint64_t)N->isDistinct() | Version);
2250   Record.append(N->elements_begin(), N->elements_end());
2251 
2252   Stream.EmitRecord(bitc::METADATA_EXPRESSION, Record, Abbrev);
2253   Record.clear();
2254 }
2255 
2256 void ModuleBitcodeWriter::writeDIGlobalVariableExpression(
2257     const DIGlobalVariableExpression *N, SmallVectorImpl<uint64_t> &Record,
2258     unsigned Abbrev) {
2259   Record.push_back(N->isDistinct());
2260   Record.push_back(VE.getMetadataOrNullID(N->getVariable()));
2261   Record.push_back(VE.getMetadataOrNullID(N->getExpression()));
2262 
2263   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR_EXPR, Record, Abbrev);
2264   Record.clear();
2265 }
2266 
2267 void ModuleBitcodeWriter::writeDIObjCProperty(const DIObjCProperty *N,
2268                                               SmallVectorImpl<uint64_t> &Record,
2269                                               unsigned Abbrev) {
2270   Record.push_back(N->isDistinct());
2271   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2272   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2273   Record.push_back(N->getLine());
2274   Record.push_back(VE.getMetadataOrNullID(N->getRawSetterName()));
2275   Record.push_back(VE.getMetadataOrNullID(N->getRawGetterName()));
2276   Record.push_back(N->getAttributes());
2277   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2278 
2279   Stream.EmitRecord(bitc::METADATA_OBJC_PROPERTY, Record, Abbrev);
2280   Record.clear();
2281 }
2282 
2283 void ModuleBitcodeWriter::writeDIImportedEntity(
2284     const DIImportedEntity *N, SmallVectorImpl<uint64_t> &Record,
2285     unsigned Abbrev) {
2286   Record.push_back(N->isDistinct());
2287   Record.push_back(N->getTag());
2288   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2289   Record.push_back(VE.getMetadataOrNullID(N->getEntity()));
2290   Record.push_back(N->getLine());
2291   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2292   Record.push_back(VE.getMetadataOrNullID(N->getRawFile()));
2293   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
2294 
2295   Stream.EmitRecord(bitc::METADATA_IMPORTED_ENTITY, Record, Abbrev);
2296   Record.clear();
2297 }
2298 
2299 unsigned ModuleBitcodeWriter::createNamedMetadataAbbrev() {
2300   auto Abbv = std::make_shared<BitCodeAbbrev>();
2301   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
2302   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2303   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2304   return Stream.EmitAbbrev(std::move(Abbv));
2305 }
2306 
2307 void ModuleBitcodeWriter::writeNamedMetadata(
2308     SmallVectorImpl<uint64_t> &Record) {
2309   if (M.named_metadata_empty())
2310     return;
2311 
2312   unsigned Abbrev = createNamedMetadataAbbrev();
2313   for (const NamedMDNode &NMD : M.named_metadata()) {
2314     // Write name.
2315     StringRef Str = NMD.getName();
2316     Record.append(Str.bytes_begin(), Str.bytes_end());
2317     Stream.EmitRecord(bitc::METADATA_NAME, Record, Abbrev);
2318     Record.clear();
2319 
2320     // Write named metadata operands.
2321     for (const MDNode *N : NMD.operands())
2322       Record.push_back(VE.getMetadataID(N));
2323     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
2324     Record.clear();
2325   }
2326 }
2327 
2328 unsigned ModuleBitcodeWriter::createMetadataStringsAbbrev() {
2329   auto Abbv = std::make_shared<BitCodeAbbrev>();
2330   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRINGS));
2331   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // # of strings
2332   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // offset to chars
2333   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
2334   return Stream.EmitAbbrev(std::move(Abbv));
2335 }
2336 
2337 /// Write out a record for MDString.
2338 ///
2339 /// All the metadata strings in a metadata block are emitted in a single
2340 /// record.  The sizes and strings themselves are shoved into a blob.
2341 void ModuleBitcodeWriter::writeMetadataStrings(
2342     ArrayRef<const Metadata *> Strings, SmallVectorImpl<uint64_t> &Record) {
2343   if (Strings.empty())
2344     return;
2345 
2346   // Start the record with the number of strings.
2347   Record.push_back(bitc::METADATA_STRINGS);
2348   Record.push_back(Strings.size());
2349 
2350   // Emit the sizes of the strings in the blob.
2351   SmallString<256> Blob;
2352   {
2353     BitstreamWriter W(Blob);
2354     for (const Metadata *MD : Strings)
2355       W.EmitVBR(cast<MDString>(MD)->getLength(), 6);
2356     W.FlushToWord();
2357   }
2358 
2359   // Add the offset to the strings to the record.
2360   Record.push_back(Blob.size());
2361 
2362   // Add the strings to the blob.
2363   for (const Metadata *MD : Strings)
2364     Blob.append(cast<MDString>(MD)->getString());
2365 
2366   // Emit the final record.
2367   Stream.EmitRecordWithBlob(createMetadataStringsAbbrev(), Record, Blob);
2368   Record.clear();
2369 }
2370 
2371 // Generates an enum to use as an index in the Abbrev array of Metadata record.
2372 enum MetadataAbbrev : unsigned {
2373 #define HANDLE_MDNODE_LEAF(CLASS) CLASS##AbbrevID,
2374 #include "llvm/IR/Metadata.def"
2375   LastPlusOne
2376 };
2377 
2378 void ModuleBitcodeWriter::writeMetadataRecords(
2379     ArrayRef<const Metadata *> MDs, SmallVectorImpl<uint64_t> &Record,
2380     std::vector<unsigned> *MDAbbrevs, std::vector<uint64_t> *IndexPos) {
2381   if (MDs.empty())
2382     return;
2383 
2384   // Initialize MDNode abbreviations.
2385 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
2386 #include "llvm/IR/Metadata.def"
2387 
2388   for (const Metadata *MD : MDs) {
2389     if (IndexPos)
2390       IndexPos->push_back(Stream.GetCurrentBitNo());
2391     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
2392       assert(N->isResolved() && "Expected forward references to be resolved");
2393 
2394       switch (N->getMetadataID()) {
2395       default:
2396         llvm_unreachable("Invalid MDNode subclass");
2397 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
2398   case Metadata::CLASS##Kind:                                                  \
2399     if (MDAbbrevs)                                                             \
2400       write##CLASS(cast<CLASS>(N), Record,                                     \
2401                    (*MDAbbrevs)[MetadataAbbrev::CLASS##AbbrevID]);             \
2402     else                                                                       \
2403       write##CLASS(cast<CLASS>(N), Record, CLASS##Abbrev);                     \
2404     continue;
2405 #include "llvm/IR/Metadata.def"
2406       }
2407     }
2408     if (auto *AL = dyn_cast<DIArgList>(MD)) {
2409       writeDIArgList(AL, Record);
2410       continue;
2411     }
2412     writeValueAsMetadata(cast<ValueAsMetadata>(MD), Record);
2413   }
2414 }
2415 
2416 void ModuleBitcodeWriter::writeModuleMetadata() {
2417   if (!VE.hasMDs() && M.named_metadata_empty())
2418     return;
2419 
2420   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 4);
2421   SmallVector<uint64_t, 64> Record;
2422 
2423   // Emit all abbrevs upfront, so that the reader can jump in the middle of the
2424   // block and load any metadata.
2425   std::vector<unsigned> MDAbbrevs;
2426 
2427   MDAbbrevs.resize(MetadataAbbrev::LastPlusOne);
2428   MDAbbrevs[MetadataAbbrev::DILocationAbbrevID] = createDILocationAbbrev();
2429   MDAbbrevs[MetadataAbbrev::GenericDINodeAbbrevID] =
2430       createGenericDINodeAbbrev();
2431 
2432   auto Abbv = std::make_shared<BitCodeAbbrev>();
2433   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX_OFFSET));
2434   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2435   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2436   unsigned OffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2437 
2438   Abbv = std::make_shared<BitCodeAbbrev>();
2439   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX));
2440   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2441   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2442   unsigned IndexAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2443 
2444   // Emit MDStrings together upfront.
2445   writeMetadataStrings(VE.getMDStrings(), Record);
2446 
2447   // We only emit an index for the metadata record if we have more than a given
2448   // (naive) threshold of metadatas, otherwise it is not worth it.
2449   if (VE.getNonMDStrings().size() > IndexThreshold) {
2450     // Write a placeholder value in for the offset of the metadata index,
2451     // which is written after the records, so that it can include
2452     // the offset of each entry. The placeholder offset will be
2453     // updated after all records are emitted.
2454     uint64_t Vals[] = {0, 0};
2455     Stream.EmitRecord(bitc::METADATA_INDEX_OFFSET, Vals, OffsetAbbrev);
2456   }
2457 
2458   // Compute and save the bit offset to the current position, which will be
2459   // patched when we emit the index later. We can simply subtract the 64-bit
2460   // fixed size from the current bit number to get the location to backpatch.
2461   uint64_t IndexOffsetRecordBitPos = Stream.GetCurrentBitNo();
2462 
2463   // This index will contain the bitpos for each individual record.
2464   std::vector<uint64_t> IndexPos;
2465   IndexPos.reserve(VE.getNonMDStrings().size());
2466 
2467   // Write all the records
2468   writeMetadataRecords(VE.getNonMDStrings(), Record, &MDAbbrevs, &IndexPos);
2469 
2470   if (VE.getNonMDStrings().size() > IndexThreshold) {
2471     // Now that we have emitted all the records we will emit the index. But
2472     // first
2473     // backpatch the forward reference so that the reader can skip the records
2474     // efficiently.
2475     Stream.BackpatchWord64(IndexOffsetRecordBitPos - 64,
2476                            Stream.GetCurrentBitNo() - IndexOffsetRecordBitPos);
2477 
2478     // Delta encode the index.
2479     uint64_t PreviousValue = IndexOffsetRecordBitPos;
2480     for (auto &Elt : IndexPos) {
2481       auto EltDelta = Elt - PreviousValue;
2482       PreviousValue = Elt;
2483       Elt = EltDelta;
2484     }
2485     // Emit the index record.
2486     Stream.EmitRecord(bitc::METADATA_INDEX, IndexPos, IndexAbbrev);
2487     IndexPos.clear();
2488   }
2489 
2490   // Write the named metadata now.
2491   writeNamedMetadata(Record);
2492 
2493   auto AddDeclAttachedMetadata = [&](const GlobalObject &GO) {
2494     SmallVector<uint64_t, 4> Record;
2495     Record.push_back(VE.getValueID(&GO));
2496     pushGlobalMetadataAttachment(Record, GO);
2497     Stream.EmitRecord(bitc::METADATA_GLOBAL_DECL_ATTACHMENT, Record);
2498   };
2499   for (const Function &F : M)
2500     if (F.isDeclaration() && F.hasMetadata())
2501       AddDeclAttachedMetadata(F);
2502   // FIXME: Only store metadata for declarations here, and move data for global
2503   // variable definitions to a separate block (PR28134).
2504   for (const GlobalVariable &GV : M.globals())
2505     if (GV.hasMetadata())
2506       AddDeclAttachedMetadata(GV);
2507 
2508   Stream.ExitBlock();
2509 }
2510 
2511 void ModuleBitcodeWriter::writeFunctionMetadata(const Function &F) {
2512   if (!VE.hasMDs())
2513     return;
2514 
2515   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
2516   SmallVector<uint64_t, 64> Record;
2517   writeMetadataStrings(VE.getMDStrings(), Record);
2518   writeMetadataRecords(VE.getNonMDStrings(), Record);
2519   Stream.ExitBlock();
2520 }
2521 
2522 void ModuleBitcodeWriter::pushGlobalMetadataAttachment(
2523     SmallVectorImpl<uint64_t> &Record, const GlobalObject &GO) {
2524   // [n x [id, mdnode]]
2525   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2526   GO.getAllMetadata(MDs);
2527   for (const auto &I : MDs) {
2528     Record.push_back(I.first);
2529     Record.push_back(VE.getMetadataID(I.second));
2530   }
2531 }
2532 
2533 void ModuleBitcodeWriter::writeFunctionMetadataAttachment(const Function &F) {
2534   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
2535 
2536   SmallVector<uint64_t, 64> Record;
2537 
2538   if (F.hasMetadata()) {
2539     pushGlobalMetadataAttachment(Record, F);
2540     Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2541     Record.clear();
2542   }
2543 
2544   // Write metadata attachments
2545   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
2546   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2547   for (const BasicBlock &BB : F)
2548     for (const Instruction &I : BB) {
2549       MDs.clear();
2550       I.getAllMetadataOtherThanDebugLoc(MDs);
2551 
2552       // If no metadata, ignore instruction.
2553       if (MDs.empty()) continue;
2554 
2555       Record.push_back(VE.getInstructionID(&I));
2556 
2557       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
2558         Record.push_back(MDs[i].first);
2559         Record.push_back(VE.getMetadataID(MDs[i].second));
2560       }
2561       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2562       Record.clear();
2563     }
2564 
2565   Stream.ExitBlock();
2566 }
2567 
2568 void ModuleBitcodeWriter::writeModuleMetadataKinds() {
2569   SmallVector<uint64_t, 64> Record;
2570 
2571   // Write metadata kinds
2572   // METADATA_KIND - [n x [id, name]]
2573   SmallVector<StringRef, 8> Names;
2574   M.getMDKindNames(Names);
2575 
2576   if (Names.empty()) return;
2577 
2578   Stream.EnterSubblock(bitc::METADATA_KIND_BLOCK_ID, 3);
2579 
2580   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
2581     Record.push_back(MDKindID);
2582     StringRef KName = Names[MDKindID];
2583     Record.append(KName.begin(), KName.end());
2584 
2585     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
2586     Record.clear();
2587   }
2588 
2589   Stream.ExitBlock();
2590 }
2591 
2592 void ModuleBitcodeWriter::writeOperandBundleTags() {
2593   // Write metadata kinds
2594   //
2595   // OPERAND_BUNDLE_TAGS_BLOCK_ID : N x OPERAND_BUNDLE_TAG
2596   //
2597   // OPERAND_BUNDLE_TAG - [strchr x N]
2598 
2599   SmallVector<StringRef, 8> Tags;
2600   M.getOperandBundleTags(Tags);
2601 
2602   if (Tags.empty())
2603     return;
2604 
2605   Stream.EnterSubblock(bitc::OPERAND_BUNDLE_TAGS_BLOCK_ID, 3);
2606 
2607   SmallVector<uint64_t, 64> Record;
2608 
2609   for (auto Tag : Tags) {
2610     Record.append(Tag.begin(), Tag.end());
2611 
2612     Stream.EmitRecord(bitc::OPERAND_BUNDLE_TAG, Record, 0);
2613     Record.clear();
2614   }
2615 
2616   Stream.ExitBlock();
2617 }
2618 
2619 void ModuleBitcodeWriter::writeSyncScopeNames() {
2620   SmallVector<StringRef, 8> SSNs;
2621   M.getContext().getSyncScopeNames(SSNs);
2622   if (SSNs.empty())
2623     return;
2624 
2625   Stream.EnterSubblock(bitc::SYNC_SCOPE_NAMES_BLOCK_ID, 2);
2626 
2627   SmallVector<uint64_t, 64> Record;
2628   for (auto SSN : SSNs) {
2629     Record.append(SSN.begin(), SSN.end());
2630     Stream.EmitRecord(bitc::SYNC_SCOPE_NAME, Record, 0);
2631     Record.clear();
2632   }
2633 
2634   Stream.ExitBlock();
2635 }
2636 
2637 void ModuleBitcodeWriter::writeConstants(unsigned FirstVal, unsigned LastVal,
2638                                          bool isGlobal) {
2639   if (FirstVal == LastVal) return;
2640 
2641   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
2642 
2643   unsigned AggregateAbbrev = 0;
2644   unsigned String8Abbrev = 0;
2645   unsigned CString7Abbrev = 0;
2646   unsigned CString6Abbrev = 0;
2647   // If this is a constant pool for the module, emit module-specific abbrevs.
2648   if (isGlobal) {
2649     // Abbrev for CST_CODE_AGGREGATE.
2650     auto Abbv = std::make_shared<BitCodeAbbrev>();
2651     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
2652     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2653     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
2654     AggregateAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2655 
2656     // Abbrev for CST_CODE_STRING.
2657     Abbv = std::make_shared<BitCodeAbbrev>();
2658     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
2659     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2660     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2661     String8Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2662     // Abbrev for CST_CODE_CSTRING.
2663     Abbv = std::make_shared<BitCodeAbbrev>();
2664     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2665     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2666     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2667     CString7Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2668     // Abbrev for CST_CODE_CSTRING.
2669     Abbv = std::make_shared<BitCodeAbbrev>();
2670     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2671     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2672     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2673     CString6Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2674   }
2675 
2676   SmallVector<uint64_t, 64> Record;
2677 
2678   const ValueEnumerator::ValueList &Vals = VE.getValues();
2679   Type *LastTy = nullptr;
2680   for (unsigned i = FirstVal; i != LastVal; ++i) {
2681     const Value *V = Vals[i].first;
2682     // If we need to switch types, do so now.
2683     if (V->getType() != LastTy) {
2684       LastTy = V->getType();
2685       Record.push_back(VE.getTypeID(LastTy));
2686       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
2687                         CONSTANTS_SETTYPE_ABBREV);
2688       Record.clear();
2689     }
2690 
2691     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
2692       Record.push_back(VE.getTypeID(IA->getFunctionType()));
2693       Record.push_back(
2694           unsigned(IA->hasSideEffects()) | unsigned(IA->isAlignStack()) << 1 |
2695           unsigned(IA->getDialect() & 1) << 2 | unsigned(IA->canThrow()) << 3);
2696 
2697       // Add the asm string.
2698       const std::string &AsmStr = IA->getAsmString();
2699       Record.push_back(AsmStr.size());
2700       Record.append(AsmStr.begin(), AsmStr.end());
2701 
2702       // Add the constraint string.
2703       const std::string &ConstraintStr = IA->getConstraintString();
2704       Record.push_back(ConstraintStr.size());
2705       Record.append(ConstraintStr.begin(), ConstraintStr.end());
2706       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
2707       Record.clear();
2708       continue;
2709     }
2710     const Constant *C = cast<Constant>(V);
2711     unsigned Code = -1U;
2712     unsigned AbbrevToUse = 0;
2713     if (C->isNullValue()) {
2714       Code = bitc::CST_CODE_NULL;
2715     } else if (isa<PoisonValue>(C)) {
2716       Code = bitc::CST_CODE_POISON;
2717     } else if (isa<UndefValue>(C)) {
2718       Code = bitc::CST_CODE_UNDEF;
2719     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
2720       if (IV->getBitWidth() <= 64) {
2721         uint64_t V = IV->getSExtValue();
2722         emitSignedInt64(Record, V);
2723         Code = bitc::CST_CODE_INTEGER;
2724         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
2725       } else {                             // Wide integers, > 64 bits in size.
2726         emitWideAPInt(Record, IV->getValue());
2727         Code = bitc::CST_CODE_WIDE_INTEGER;
2728       }
2729     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
2730       Code = bitc::CST_CODE_FLOAT;
2731       Type *Ty = CFP->getType()->getScalarType();
2732       if (Ty->isHalfTy() || Ty->isBFloatTy() || Ty->isFloatTy() ||
2733           Ty->isDoubleTy()) {
2734         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
2735       } else if (Ty->isX86_FP80Ty()) {
2736         // api needed to prevent premature destruction
2737         // bits are not in the same order as a normal i80 APInt, compensate.
2738         APInt api = CFP->getValueAPF().bitcastToAPInt();
2739         const uint64_t *p = api.getRawData();
2740         Record.push_back((p[1] << 48) | (p[0] >> 16));
2741         Record.push_back(p[0] & 0xffffLL);
2742       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
2743         APInt api = CFP->getValueAPF().bitcastToAPInt();
2744         const uint64_t *p = api.getRawData();
2745         Record.push_back(p[0]);
2746         Record.push_back(p[1]);
2747       } else {
2748         assert(0 && "Unknown FP type!");
2749       }
2750     } else if (isa<ConstantDataSequential>(C) &&
2751                cast<ConstantDataSequential>(C)->isString()) {
2752       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
2753       // Emit constant strings specially.
2754       unsigned NumElts = Str->getNumElements();
2755       // If this is a null-terminated string, use the denser CSTRING encoding.
2756       if (Str->isCString()) {
2757         Code = bitc::CST_CODE_CSTRING;
2758         --NumElts;  // Don't encode the null, which isn't allowed by char6.
2759       } else {
2760         Code = bitc::CST_CODE_STRING;
2761         AbbrevToUse = String8Abbrev;
2762       }
2763       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
2764       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
2765       for (unsigned i = 0; i != NumElts; ++i) {
2766         unsigned char V = Str->getElementAsInteger(i);
2767         Record.push_back(V);
2768         isCStr7 &= (V & 128) == 0;
2769         if (isCStrChar6)
2770           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
2771       }
2772 
2773       if (isCStrChar6)
2774         AbbrevToUse = CString6Abbrev;
2775       else if (isCStr7)
2776         AbbrevToUse = CString7Abbrev;
2777     } else if (const ConstantDataSequential *CDS =
2778                   dyn_cast<ConstantDataSequential>(C)) {
2779       Code = bitc::CST_CODE_DATA;
2780       Type *EltTy = CDS->getElementType();
2781       if (isa<IntegerType>(EltTy)) {
2782         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2783           Record.push_back(CDS->getElementAsInteger(i));
2784       } else {
2785         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2786           Record.push_back(
2787               CDS->getElementAsAPFloat(i).bitcastToAPInt().getLimitedValue());
2788       }
2789     } else if (isa<ConstantAggregate>(C)) {
2790       Code = bitc::CST_CODE_AGGREGATE;
2791       for (const Value *Op : C->operands())
2792         Record.push_back(VE.getValueID(Op));
2793       AbbrevToUse = AggregateAbbrev;
2794     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
2795       switch (CE->getOpcode()) {
2796       default:
2797         if (Instruction::isCast(CE->getOpcode())) {
2798           Code = bitc::CST_CODE_CE_CAST;
2799           Record.push_back(getEncodedCastOpcode(CE->getOpcode()));
2800           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2801           Record.push_back(VE.getValueID(C->getOperand(0)));
2802           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
2803         } else {
2804           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
2805           Code = bitc::CST_CODE_CE_BINOP;
2806           Record.push_back(getEncodedBinaryOpcode(CE->getOpcode()));
2807           Record.push_back(VE.getValueID(C->getOperand(0)));
2808           Record.push_back(VE.getValueID(C->getOperand(1)));
2809           uint64_t Flags = getOptimizationFlags(CE);
2810           if (Flags != 0)
2811             Record.push_back(Flags);
2812         }
2813         break;
2814       case Instruction::FNeg: {
2815         assert(CE->getNumOperands() == 1 && "Unknown constant expr!");
2816         Code = bitc::CST_CODE_CE_UNOP;
2817         Record.push_back(getEncodedUnaryOpcode(CE->getOpcode()));
2818         Record.push_back(VE.getValueID(C->getOperand(0)));
2819         uint64_t Flags = getOptimizationFlags(CE);
2820         if (Flags != 0)
2821           Record.push_back(Flags);
2822         break;
2823       }
2824       case Instruction::GetElementPtr: {
2825         Code = bitc::CST_CODE_CE_GEP;
2826         const auto *GO = cast<GEPOperator>(C);
2827         Record.push_back(VE.getTypeID(GO->getSourceElementType()));
2828         Record.push_back(getOptimizationFlags(GO));
2829         if (std::optional<ConstantRange> Range = GO->getInRange()) {
2830           Code = bitc::CST_CODE_CE_GEP_WITH_INRANGE;
2831           emitConstantRange(Record, *Range, /*EmitBitWidth=*/true);
2832         }
2833         for (const Value *Op : CE->operands()) {
2834           Record.push_back(VE.getTypeID(Op->getType()));
2835           Record.push_back(VE.getValueID(Op));
2836         }
2837         break;
2838       }
2839       case Instruction::ExtractElement:
2840         Code = bitc::CST_CODE_CE_EXTRACTELT;
2841         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2842         Record.push_back(VE.getValueID(C->getOperand(0)));
2843         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
2844         Record.push_back(VE.getValueID(C->getOperand(1)));
2845         break;
2846       case Instruction::InsertElement:
2847         Code = bitc::CST_CODE_CE_INSERTELT;
2848         Record.push_back(VE.getValueID(C->getOperand(0)));
2849         Record.push_back(VE.getValueID(C->getOperand(1)));
2850         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
2851         Record.push_back(VE.getValueID(C->getOperand(2)));
2852         break;
2853       case Instruction::ShuffleVector:
2854         // If the return type and argument types are the same, this is a
2855         // standard shufflevector instruction.  If the types are different,
2856         // then the shuffle is widening or truncating the input vectors, and
2857         // the argument type must also be encoded.
2858         if (C->getType() == C->getOperand(0)->getType()) {
2859           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
2860         } else {
2861           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
2862           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2863         }
2864         Record.push_back(VE.getValueID(C->getOperand(0)));
2865         Record.push_back(VE.getValueID(C->getOperand(1)));
2866         Record.push_back(VE.getValueID(CE->getShuffleMaskForBitcode()));
2867         break;
2868       }
2869     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
2870       Code = bitc::CST_CODE_BLOCKADDRESS;
2871       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
2872       Record.push_back(VE.getValueID(BA->getFunction()));
2873       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
2874     } else if (const auto *Equiv = dyn_cast<DSOLocalEquivalent>(C)) {
2875       Code = bitc::CST_CODE_DSO_LOCAL_EQUIVALENT;
2876       Record.push_back(VE.getTypeID(Equiv->getGlobalValue()->getType()));
2877       Record.push_back(VE.getValueID(Equiv->getGlobalValue()));
2878     } else if (const auto *NC = dyn_cast<NoCFIValue>(C)) {
2879       Code = bitc::CST_CODE_NO_CFI_VALUE;
2880       Record.push_back(VE.getTypeID(NC->getGlobalValue()->getType()));
2881       Record.push_back(VE.getValueID(NC->getGlobalValue()));
2882     } else if (const auto *CPA = dyn_cast<ConstantPtrAuth>(C)) {
2883       Code = bitc::CST_CODE_PTRAUTH;
2884       Record.push_back(VE.getValueID(CPA->getPointer()));
2885       Record.push_back(VE.getValueID(CPA->getKey()));
2886       Record.push_back(VE.getValueID(CPA->getDiscriminator()));
2887       Record.push_back(VE.getValueID(CPA->getAddrDiscriminator()));
2888     } else {
2889 #ifndef NDEBUG
2890       C->dump();
2891 #endif
2892       llvm_unreachable("Unknown constant!");
2893     }
2894     Stream.EmitRecord(Code, Record, AbbrevToUse);
2895     Record.clear();
2896   }
2897 
2898   Stream.ExitBlock();
2899 }
2900 
2901 void ModuleBitcodeWriter::writeModuleConstants() {
2902   const ValueEnumerator::ValueList &Vals = VE.getValues();
2903 
2904   // Find the first constant to emit, which is the first non-globalvalue value.
2905   // We know globalvalues have been emitted by WriteModuleInfo.
2906   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
2907     if (!isa<GlobalValue>(Vals[i].first)) {
2908       writeConstants(i, Vals.size(), true);
2909       return;
2910     }
2911   }
2912 }
2913 
2914 /// pushValueAndType - The file has to encode both the value and type id for
2915 /// many values, because we need to know what type to create for forward
2916 /// references.  However, most operands are not forward references, so this type
2917 /// field is not needed.
2918 ///
2919 /// This function adds V's value ID to Vals.  If the value ID is higher than the
2920 /// instruction ID, then it is a forward reference, and it also includes the
2921 /// type ID.  The value ID that is written is encoded relative to the InstID.
2922 bool ModuleBitcodeWriter::pushValueAndType(const Value *V, unsigned InstID,
2923                                            SmallVectorImpl<unsigned> &Vals) {
2924   unsigned ValID = VE.getValueID(V);
2925   // Make encoding relative to the InstID.
2926   Vals.push_back(InstID - ValID);
2927   if (ValID >= InstID) {
2928     Vals.push_back(VE.getTypeID(V->getType()));
2929     return true;
2930   }
2931   return false;
2932 }
2933 
2934 void ModuleBitcodeWriter::writeOperandBundles(const CallBase &CS,
2935                                               unsigned InstID) {
2936   SmallVector<unsigned, 64> Record;
2937   LLVMContext &C = CS.getContext();
2938 
2939   for (unsigned i = 0, e = CS.getNumOperandBundles(); i != e; ++i) {
2940     const auto &Bundle = CS.getOperandBundleAt(i);
2941     Record.push_back(C.getOperandBundleTagID(Bundle.getTagName()));
2942 
2943     for (auto &Input : Bundle.Inputs)
2944       pushValueAndType(Input, InstID, Record);
2945 
2946     Stream.EmitRecord(bitc::FUNC_CODE_OPERAND_BUNDLE, Record);
2947     Record.clear();
2948   }
2949 }
2950 
2951 /// pushValue - Like pushValueAndType, but where the type of the value is
2952 /// omitted (perhaps it was already encoded in an earlier operand).
2953 void ModuleBitcodeWriter::pushValue(const Value *V, unsigned InstID,
2954                                     SmallVectorImpl<unsigned> &Vals) {
2955   unsigned ValID = VE.getValueID(V);
2956   Vals.push_back(InstID - ValID);
2957 }
2958 
2959 void ModuleBitcodeWriter::pushValueSigned(const Value *V, unsigned InstID,
2960                                           SmallVectorImpl<uint64_t> &Vals) {
2961   unsigned ValID = VE.getValueID(V);
2962   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
2963   emitSignedInt64(Vals, diff);
2964 }
2965 
2966 /// WriteInstruction - Emit an instruction to the specified stream.
2967 void ModuleBitcodeWriter::writeInstruction(const Instruction &I,
2968                                            unsigned InstID,
2969                                            SmallVectorImpl<unsigned> &Vals) {
2970   unsigned Code = 0;
2971   unsigned AbbrevToUse = 0;
2972   VE.setInstructionID(&I);
2973   switch (I.getOpcode()) {
2974   default:
2975     if (Instruction::isCast(I.getOpcode())) {
2976       Code = bitc::FUNC_CODE_INST_CAST;
2977       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2978         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
2979       Vals.push_back(VE.getTypeID(I.getType()));
2980       Vals.push_back(getEncodedCastOpcode(I.getOpcode()));
2981       uint64_t Flags = getOptimizationFlags(&I);
2982       if (Flags != 0) {
2983         if (AbbrevToUse == FUNCTION_INST_CAST_ABBREV)
2984           AbbrevToUse = FUNCTION_INST_CAST_FLAGS_ABBREV;
2985         Vals.push_back(Flags);
2986       }
2987     } else {
2988       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
2989       Code = bitc::FUNC_CODE_INST_BINOP;
2990       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2991         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
2992       pushValue(I.getOperand(1), InstID, Vals);
2993       Vals.push_back(getEncodedBinaryOpcode(I.getOpcode()));
2994       uint64_t Flags = getOptimizationFlags(&I);
2995       if (Flags != 0) {
2996         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
2997           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
2998         Vals.push_back(Flags);
2999       }
3000     }
3001     break;
3002   case Instruction::FNeg: {
3003     Code = bitc::FUNC_CODE_INST_UNOP;
3004     if (!pushValueAndType(I.getOperand(0), InstID, Vals))
3005       AbbrevToUse = FUNCTION_INST_UNOP_ABBREV;
3006     Vals.push_back(getEncodedUnaryOpcode(I.getOpcode()));
3007     uint64_t Flags = getOptimizationFlags(&I);
3008     if (Flags != 0) {
3009       if (AbbrevToUse == FUNCTION_INST_UNOP_ABBREV)
3010         AbbrevToUse = FUNCTION_INST_UNOP_FLAGS_ABBREV;
3011       Vals.push_back(Flags);
3012     }
3013     break;
3014   }
3015   case Instruction::GetElementPtr: {
3016     Code = bitc::FUNC_CODE_INST_GEP;
3017     AbbrevToUse = FUNCTION_INST_GEP_ABBREV;
3018     auto &GEPInst = cast<GetElementPtrInst>(I);
3019     Vals.push_back(getOptimizationFlags(&I));
3020     Vals.push_back(VE.getTypeID(GEPInst.getSourceElementType()));
3021     for (const Value *Op : I.operands())
3022       pushValueAndType(Op, InstID, Vals);
3023     break;
3024   }
3025   case Instruction::ExtractValue: {
3026     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
3027     pushValueAndType(I.getOperand(0), InstID, Vals);
3028     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
3029     Vals.append(EVI->idx_begin(), EVI->idx_end());
3030     break;
3031   }
3032   case Instruction::InsertValue: {
3033     Code = bitc::FUNC_CODE_INST_INSERTVAL;
3034     pushValueAndType(I.getOperand(0), InstID, Vals);
3035     pushValueAndType(I.getOperand(1), InstID, Vals);
3036     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
3037     Vals.append(IVI->idx_begin(), IVI->idx_end());
3038     break;
3039   }
3040   case Instruction::Select: {
3041     Code = bitc::FUNC_CODE_INST_VSELECT;
3042     pushValueAndType(I.getOperand(1), InstID, Vals);
3043     pushValue(I.getOperand(2), InstID, Vals);
3044     pushValueAndType(I.getOperand(0), InstID, Vals);
3045     uint64_t Flags = getOptimizationFlags(&I);
3046     if (Flags != 0)
3047       Vals.push_back(Flags);
3048     break;
3049   }
3050   case Instruction::ExtractElement:
3051     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
3052     pushValueAndType(I.getOperand(0), InstID, Vals);
3053     pushValueAndType(I.getOperand(1), InstID, Vals);
3054     break;
3055   case Instruction::InsertElement:
3056     Code = bitc::FUNC_CODE_INST_INSERTELT;
3057     pushValueAndType(I.getOperand(0), InstID, Vals);
3058     pushValue(I.getOperand(1), InstID, Vals);
3059     pushValueAndType(I.getOperand(2), InstID, Vals);
3060     break;
3061   case Instruction::ShuffleVector:
3062     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
3063     pushValueAndType(I.getOperand(0), InstID, Vals);
3064     pushValue(I.getOperand(1), InstID, Vals);
3065     pushValue(cast<ShuffleVectorInst>(I).getShuffleMaskForBitcode(), InstID,
3066               Vals);
3067     break;
3068   case Instruction::ICmp:
3069   case Instruction::FCmp: {
3070     // compare returning Int1Ty or vector of Int1Ty
3071     Code = bitc::FUNC_CODE_INST_CMP2;
3072     pushValueAndType(I.getOperand(0), InstID, Vals);
3073     pushValue(I.getOperand(1), InstID, Vals);
3074     Vals.push_back(cast<CmpInst>(I).getPredicate());
3075     uint64_t Flags = getOptimizationFlags(&I);
3076     if (Flags != 0)
3077       Vals.push_back(Flags);
3078     break;
3079   }
3080 
3081   case Instruction::Ret:
3082     {
3083       Code = bitc::FUNC_CODE_INST_RET;
3084       unsigned NumOperands = I.getNumOperands();
3085       if (NumOperands == 0)
3086         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
3087       else if (NumOperands == 1) {
3088         if (!pushValueAndType(I.getOperand(0), InstID, Vals))
3089           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
3090       } else {
3091         for (const Value *Op : I.operands())
3092           pushValueAndType(Op, InstID, Vals);
3093       }
3094     }
3095     break;
3096   case Instruction::Br:
3097     {
3098       Code = bitc::FUNC_CODE_INST_BR;
3099       const BranchInst &II = cast<BranchInst>(I);
3100       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
3101       if (II.isConditional()) {
3102         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
3103         pushValue(II.getCondition(), InstID, Vals);
3104       }
3105     }
3106     break;
3107   case Instruction::Switch:
3108     {
3109       Code = bitc::FUNC_CODE_INST_SWITCH;
3110       const SwitchInst &SI = cast<SwitchInst>(I);
3111       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
3112       pushValue(SI.getCondition(), InstID, Vals);
3113       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
3114       for (auto Case : SI.cases()) {
3115         Vals.push_back(VE.getValueID(Case.getCaseValue()));
3116         Vals.push_back(VE.getValueID(Case.getCaseSuccessor()));
3117       }
3118     }
3119     break;
3120   case Instruction::IndirectBr:
3121     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
3122     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
3123     // Encode the address operand as relative, but not the basic blocks.
3124     pushValue(I.getOperand(0), InstID, Vals);
3125     for (const Value *Op : drop_begin(I.operands()))
3126       Vals.push_back(VE.getValueID(Op));
3127     break;
3128 
3129   case Instruction::Invoke: {
3130     const InvokeInst *II = cast<InvokeInst>(&I);
3131     const Value *Callee = II->getCalledOperand();
3132     FunctionType *FTy = II->getFunctionType();
3133 
3134     if (II->hasOperandBundles())
3135       writeOperandBundles(*II, InstID);
3136 
3137     Code = bitc::FUNC_CODE_INST_INVOKE;
3138 
3139     Vals.push_back(VE.getAttributeListID(II->getAttributes()));
3140     Vals.push_back(II->getCallingConv() | 1 << 13);
3141     Vals.push_back(VE.getValueID(II->getNormalDest()));
3142     Vals.push_back(VE.getValueID(II->getUnwindDest()));
3143     Vals.push_back(VE.getTypeID(FTy));
3144     pushValueAndType(Callee, InstID, Vals);
3145 
3146     // Emit value #'s for the fixed parameters.
3147     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
3148       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
3149 
3150     // Emit type/value pairs for varargs params.
3151     if (FTy->isVarArg()) {
3152       for (unsigned i = FTy->getNumParams(), e = II->arg_size(); i != e; ++i)
3153         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
3154     }
3155     break;
3156   }
3157   case Instruction::Resume:
3158     Code = bitc::FUNC_CODE_INST_RESUME;
3159     pushValueAndType(I.getOperand(0), InstID, Vals);
3160     break;
3161   case Instruction::CleanupRet: {
3162     Code = bitc::FUNC_CODE_INST_CLEANUPRET;
3163     const auto &CRI = cast<CleanupReturnInst>(I);
3164     pushValue(CRI.getCleanupPad(), InstID, Vals);
3165     if (CRI.hasUnwindDest())
3166       Vals.push_back(VE.getValueID(CRI.getUnwindDest()));
3167     break;
3168   }
3169   case Instruction::CatchRet: {
3170     Code = bitc::FUNC_CODE_INST_CATCHRET;
3171     const auto &CRI = cast<CatchReturnInst>(I);
3172     pushValue(CRI.getCatchPad(), InstID, Vals);
3173     Vals.push_back(VE.getValueID(CRI.getSuccessor()));
3174     break;
3175   }
3176   case Instruction::CleanupPad:
3177   case Instruction::CatchPad: {
3178     const auto &FuncletPad = cast<FuncletPadInst>(I);
3179     Code = isa<CatchPadInst>(FuncletPad) ? bitc::FUNC_CODE_INST_CATCHPAD
3180                                          : bitc::FUNC_CODE_INST_CLEANUPPAD;
3181     pushValue(FuncletPad.getParentPad(), InstID, Vals);
3182 
3183     unsigned NumArgOperands = FuncletPad.arg_size();
3184     Vals.push_back(NumArgOperands);
3185     for (unsigned Op = 0; Op != NumArgOperands; ++Op)
3186       pushValueAndType(FuncletPad.getArgOperand(Op), InstID, Vals);
3187     break;
3188   }
3189   case Instruction::CatchSwitch: {
3190     Code = bitc::FUNC_CODE_INST_CATCHSWITCH;
3191     const auto &CatchSwitch = cast<CatchSwitchInst>(I);
3192 
3193     pushValue(CatchSwitch.getParentPad(), InstID, Vals);
3194 
3195     unsigned NumHandlers = CatchSwitch.getNumHandlers();
3196     Vals.push_back(NumHandlers);
3197     for (const BasicBlock *CatchPadBB : CatchSwitch.handlers())
3198       Vals.push_back(VE.getValueID(CatchPadBB));
3199 
3200     if (CatchSwitch.hasUnwindDest())
3201       Vals.push_back(VE.getValueID(CatchSwitch.getUnwindDest()));
3202     break;
3203   }
3204   case Instruction::CallBr: {
3205     const CallBrInst *CBI = cast<CallBrInst>(&I);
3206     const Value *Callee = CBI->getCalledOperand();
3207     FunctionType *FTy = CBI->getFunctionType();
3208 
3209     if (CBI->hasOperandBundles())
3210       writeOperandBundles(*CBI, InstID);
3211 
3212     Code = bitc::FUNC_CODE_INST_CALLBR;
3213 
3214     Vals.push_back(VE.getAttributeListID(CBI->getAttributes()));
3215 
3216     Vals.push_back(CBI->getCallingConv() << bitc::CALL_CCONV |
3217                    1 << bitc::CALL_EXPLICIT_TYPE);
3218 
3219     Vals.push_back(VE.getValueID(CBI->getDefaultDest()));
3220     Vals.push_back(CBI->getNumIndirectDests());
3221     for (unsigned i = 0, e = CBI->getNumIndirectDests(); i != e; ++i)
3222       Vals.push_back(VE.getValueID(CBI->getIndirectDest(i)));
3223 
3224     Vals.push_back(VE.getTypeID(FTy));
3225     pushValueAndType(Callee, InstID, Vals);
3226 
3227     // Emit value #'s for the fixed parameters.
3228     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
3229       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
3230 
3231     // Emit type/value pairs for varargs params.
3232     if (FTy->isVarArg()) {
3233       for (unsigned i = FTy->getNumParams(), e = CBI->arg_size(); i != e; ++i)
3234         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
3235     }
3236     break;
3237   }
3238   case Instruction::Unreachable:
3239     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
3240     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
3241     break;
3242 
3243   case Instruction::PHI: {
3244     const PHINode &PN = cast<PHINode>(I);
3245     Code = bitc::FUNC_CODE_INST_PHI;
3246     // With the newer instruction encoding, forward references could give
3247     // negative valued IDs.  This is most common for PHIs, so we use
3248     // signed VBRs.
3249     SmallVector<uint64_t, 128> Vals64;
3250     Vals64.push_back(VE.getTypeID(PN.getType()));
3251     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
3252       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64);
3253       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
3254     }
3255 
3256     uint64_t Flags = getOptimizationFlags(&I);
3257     if (Flags != 0)
3258       Vals64.push_back(Flags);
3259 
3260     // Emit a Vals64 vector and exit.
3261     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
3262     Vals64.clear();
3263     return;
3264   }
3265 
3266   case Instruction::LandingPad: {
3267     const LandingPadInst &LP = cast<LandingPadInst>(I);
3268     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
3269     Vals.push_back(VE.getTypeID(LP.getType()));
3270     Vals.push_back(LP.isCleanup());
3271     Vals.push_back(LP.getNumClauses());
3272     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
3273       if (LP.isCatch(I))
3274         Vals.push_back(LandingPadInst::Catch);
3275       else
3276         Vals.push_back(LandingPadInst::Filter);
3277       pushValueAndType(LP.getClause(I), InstID, Vals);
3278     }
3279     break;
3280   }
3281 
3282   case Instruction::Alloca: {
3283     Code = bitc::FUNC_CODE_INST_ALLOCA;
3284     const AllocaInst &AI = cast<AllocaInst>(I);
3285     Vals.push_back(VE.getTypeID(AI.getAllocatedType()));
3286     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
3287     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
3288     using APV = AllocaPackedValues;
3289     unsigned Record = 0;
3290     unsigned EncodedAlign = getEncodedAlign(AI.getAlign());
3291     Bitfield::set<APV::AlignLower>(
3292         Record, EncodedAlign & ((1 << APV::AlignLower::Bits) - 1));
3293     Bitfield::set<APV::AlignUpper>(Record,
3294                                    EncodedAlign >> APV::AlignLower::Bits);
3295     Bitfield::set<APV::UsedWithInAlloca>(Record, AI.isUsedWithInAlloca());
3296     Bitfield::set<APV::ExplicitType>(Record, true);
3297     Bitfield::set<APV::SwiftError>(Record, AI.isSwiftError());
3298     Vals.push_back(Record);
3299 
3300     unsigned AS = AI.getAddressSpace();
3301     if (AS != M.getDataLayout().getAllocaAddrSpace())
3302       Vals.push_back(AS);
3303     break;
3304   }
3305 
3306   case Instruction::Load:
3307     if (cast<LoadInst>(I).isAtomic()) {
3308       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
3309       pushValueAndType(I.getOperand(0), InstID, Vals);
3310     } else {
3311       Code = bitc::FUNC_CODE_INST_LOAD;
3312       if (!pushValueAndType(I.getOperand(0), InstID, Vals)) // ptr
3313         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
3314     }
3315     Vals.push_back(VE.getTypeID(I.getType()));
3316     Vals.push_back(getEncodedAlign(cast<LoadInst>(I).getAlign()));
3317     Vals.push_back(cast<LoadInst>(I).isVolatile());
3318     if (cast<LoadInst>(I).isAtomic()) {
3319       Vals.push_back(getEncodedOrdering(cast<LoadInst>(I).getOrdering()));
3320       Vals.push_back(getEncodedSyncScopeID(cast<LoadInst>(I).getSyncScopeID()));
3321     }
3322     break;
3323   case Instruction::Store:
3324     if (cast<StoreInst>(I).isAtomic())
3325       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
3326     else
3327       Code = bitc::FUNC_CODE_INST_STORE;
3328     pushValueAndType(I.getOperand(1), InstID, Vals); // ptrty + ptr
3329     pushValueAndType(I.getOperand(0), InstID, Vals); // valty + val
3330     Vals.push_back(getEncodedAlign(cast<StoreInst>(I).getAlign()));
3331     Vals.push_back(cast<StoreInst>(I).isVolatile());
3332     if (cast<StoreInst>(I).isAtomic()) {
3333       Vals.push_back(getEncodedOrdering(cast<StoreInst>(I).getOrdering()));
3334       Vals.push_back(
3335           getEncodedSyncScopeID(cast<StoreInst>(I).getSyncScopeID()));
3336     }
3337     break;
3338   case Instruction::AtomicCmpXchg:
3339     Code = bitc::FUNC_CODE_INST_CMPXCHG;
3340     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
3341     pushValueAndType(I.getOperand(1), InstID, Vals); // cmp.
3342     pushValue(I.getOperand(2), InstID, Vals);        // newval.
3343     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
3344     Vals.push_back(
3345         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
3346     Vals.push_back(
3347         getEncodedSyncScopeID(cast<AtomicCmpXchgInst>(I).getSyncScopeID()));
3348     Vals.push_back(
3349         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
3350     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
3351     Vals.push_back(getEncodedAlign(cast<AtomicCmpXchgInst>(I).getAlign()));
3352     break;
3353   case Instruction::AtomicRMW:
3354     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
3355     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
3356     pushValueAndType(I.getOperand(1), InstID, Vals); // valty + val
3357     Vals.push_back(
3358         getEncodedRMWOperation(cast<AtomicRMWInst>(I).getOperation()));
3359     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
3360     Vals.push_back(getEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
3361     Vals.push_back(
3362         getEncodedSyncScopeID(cast<AtomicRMWInst>(I).getSyncScopeID()));
3363     Vals.push_back(getEncodedAlign(cast<AtomicRMWInst>(I).getAlign()));
3364     break;
3365   case Instruction::Fence:
3366     Code = bitc::FUNC_CODE_INST_FENCE;
3367     Vals.push_back(getEncodedOrdering(cast<FenceInst>(I).getOrdering()));
3368     Vals.push_back(getEncodedSyncScopeID(cast<FenceInst>(I).getSyncScopeID()));
3369     break;
3370   case Instruction::Call: {
3371     const CallInst &CI = cast<CallInst>(I);
3372     FunctionType *FTy = CI.getFunctionType();
3373 
3374     if (CI.hasOperandBundles())
3375       writeOperandBundles(CI, InstID);
3376 
3377     Code = bitc::FUNC_CODE_INST_CALL;
3378 
3379     Vals.push_back(VE.getAttributeListID(CI.getAttributes()));
3380 
3381     unsigned Flags = getOptimizationFlags(&I);
3382     Vals.push_back(CI.getCallingConv() << bitc::CALL_CCONV |
3383                    unsigned(CI.isTailCall()) << bitc::CALL_TAIL |
3384                    unsigned(CI.isMustTailCall()) << bitc::CALL_MUSTTAIL |
3385                    1 << bitc::CALL_EXPLICIT_TYPE |
3386                    unsigned(CI.isNoTailCall()) << bitc::CALL_NOTAIL |
3387                    unsigned(Flags != 0) << bitc::CALL_FMF);
3388     if (Flags != 0)
3389       Vals.push_back(Flags);
3390 
3391     Vals.push_back(VE.getTypeID(FTy));
3392     pushValueAndType(CI.getCalledOperand(), InstID, Vals); // Callee
3393 
3394     // Emit value #'s for the fixed parameters.
3395     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
3396       // Check for labels (can happen with asm labels).
3397       if (FTy->getParamType(i)->isLabelTy())
3398         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
3399       else
3400         pushValue(CI.getArgOperand(i), InstID, Vals); // fixed param.
3401     }
3402 
3403     // Emit type/value pairs for varargs params.
3404     if (FTy->isVarArg()) {
3405       for (unsigned i = FTy->getNumParams(), e = CI.arg_size(); i != e; ++i)
3406         pushValueAndType(CI.getArgOperand(i), InstID, Vals); // varargs
3407     }
3408     break;
3409   }
3410   case Instruction::VAArg:
3411     Code = bitc::FUNC_CODE_INST_VAARG;
3412     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
3413     pushValue(I.getOperand(0), InstID, Vals);                   // valist.
3414     Vals.push_back(VE.getTypeID(I.getType())); // restype.
3415     break;
3416   case Instruction::Freeze:
3417     Code = bitc::FUNC_CODE_INST_FREEZE;
3418     pushValueAndType(I.getOperand(0), InstID, Vals);
3419     break;
3420   }
3421 
3422   Stream.EmitRecord(Code, Vals, AbbrevToUse);
3423   Vals.clear();
3424 }
3425 
3426 /// Write a GlobalValue VST to the module. The purpose of this data structure is
3427 /// to allow clients to efficiently find the function body.
3428 void ModuleBitcodeWriter::writeGlobalValueSymbolTable(
3429   DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3430   // Get the offset of the VST we are writing, and backpatch it into
3431   // the VST forward declaration record.
3432   uint64_t VSTOffset = Stream.GetCurrentBitNo();
3433   // The BitcodeStartBit was the stream offset of the identification block.
3434   VSTOffset -= bitcodeStartBit();
3435   assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
3436   // Note that we add 1 here because the offset is relative to one word
3437   // before the start of the identification block, which was historically
3438   // always the start of the regular bitcode header.
3439   Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32 + 1);
3440 
3441   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3442 
3443   auto Abbv = std::make_shared<BitCodeAbbrev>();
3444   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
3445   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
3446   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
3447   unsigned FnEntryAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3448 
3449   for (const Function &F : M) {
3450     uint64_t Record[2];
3451 
3452     if (F.isDeclaration())
3453       continue;
3454 
3455     Record[0] = VE.getValueID(&F);
3456 
3457     // Save the word offset of the function (from the start of the
3458     // actual bitcode written to the stream).
3459     uint64_t BitcodeIndex = FunctionToBitcodeIndex[&F] - bitcodeStartBit();
3460     assert((BitcodeIndex & 31) == 0 && "function block not 32-bit aligned");
3461     // Note that we add 1 here because the offset is relative to one word
3462     // before the start of the identification block, which was historically
3463     // always the start of the regular bitcode header.
3464     Record[1] = BitcodeIndex / 32 + 1;
3465 
3466     Stream.EmitRecord(bitc::VST_CODE_FNENTRY, Record, FnEntryAbbrev);
3467   }
3468 
3469   Stream.ExitBlock();
3470 }
3471 
3472 /// Emit names for arguments, instructions and basic blocks in a function.
3473 void ModuleBitcodeWriter::writeFunctionLevelValueSymbolTable(
3474     const ValueSymbolTable &VST) {
3475   if (VST.empty())
3476     return;
3477 
3478   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3479 
3480   // FIXME: Set up the abbrev, we know how many values there are!
3481   // FIXME: We know if the type names can use 7-bit ascii.
3482   SmallVector<uint64_t, 64> NameVals;
3483 
3484   for (const ValueName &Name : VST) {
3485     // Figure out the encoding to use for the name.
3486     StringEncoding Bits = getStringEncoding(Name.getKey());
3487 
3488     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
3489     NameVals.push_back(VE.getValueID(Name.getValue()));
3490 
3491     // VST_CODE_ENTRY:   [valueid, namechar x N]
3492     // VST_CODE_BBENTRY: [bbid, namechar x N]
3493     unsigned Code;
3494     if (isa<BasicBlock>(Name.getValue())) {
3495       Code = bitc::VST_CODE_BBENTRY;
3496       if (Bits == SE_Char6)
3497         AbbrevToUse = VST_BBENTRY_6_ABBREV;
3498     } else {
3499       Code = bitc::VST_CODE_ENTRY;
3500       if (Bits == SE_Char6)
3501         AbbrevToUse = VST_ENTRY_6_ABBREV;
3502       else if (Bits == SE_Fixed7)
3503         AbbrevToUse = VST_ENTRY_7_ABBREV;
3504     }
3505 
3506     for (const auto P : Name.getKey())
3507       NameVals.push_back((unsigned char)P);
3508 
3509     // Emit the finished record.
3510     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
3511     NameVals.clear();
3512   }
3513 
3514   Stream.ExitBlock();
3515 }
3516 
3517 void ModuleBitcodeWriter::writeUseList(UseListOrder &&Order) {
3518   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
3519   unsigned Code;
3520   if (isa<BasicBlock>(Order.V))
3521     Code = bitc::USELIST_CODE_BB;
3522   else
3523     Code = bitc::USELIST_CODE_DEFAULT;
3524 
3525   SmallVector<uint64_t, 64> Record(Order.Shuffle.begin(), Order.Shuffle.end());
3526   Record.push_back(VE.getValueID(Order.V));
3527   Stream.EmitRecord(Code, Record);
3528 }
3529 
3530 void ModuleBitcodeWriter::writeUseListBlock(const Function *F) {
3531   assert(VE.shouldPreserveUseListOrder() &&
3532          "Expected to be preserving use-list order");
3533 
3534   auto hasMore = [&]() {
3535     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
3536   };
3537   if (!hasMore())
3538     // Nothing to do.
3539     return;
3540 
3541   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
3542   while (hasMore()) {
3543     writeUseList(std::move(VE.UseListOrders.back()));
3544     VE.UseListOrders.pop_back();
3545   }
3546   Stream.ExitBlock();
3547 }
3548 
3549 /// Emit a function body to the module stream.
3550 void ModuleBitcodeWriter::writeFunction(
3551     const Function &F,
3552     DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3553   // Save the bitcode index of the start of this function block for recording
3554   // in the VST.
3555   FunctionToBitcodeIndex[&F] = Stream.GetCurrentBitNo();
3556 
3557   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
3558   VE.incorporateFunction(F);
3559 
3560   SmallVector<unsigned, 64> Vals;
3561 
3562   // Emit the number of basic blocks, so the reader can create them ahead of
3563   // time.
3564   Vals.push_back(VE.getBasicBlocks().size());
3565   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
3566   Vals.clear();
3567 
3568   // If there are function-local constants, emit them now.
3569   unsigned CstStart, CstEnd;
3570   VE.getFunctionConstantRange(CstStart, CstEnd);
3571   writeConstants(CstStart, CstEnd, false);
3572 
3573   // If there is function-local metadata, emit it now.
3574   writeFunctionMetadata(F);
3575 
3576   // Keep a running idea of what the instruction ID is.
3577   unsigned InstID = CstEnd;
3578 
3579   bool NeedsMetadataAttachment = F.hasMetadata();
3580 
3581   DILocation *LastDL = nullptr;
3582   SmallSetVector<Function *, 4> BlockAddressUsers;
3583 
3584   // Finally, emit all the instructions, in order.
3585   for (const BasicBlock &BB : F) {
3586     for (const Instruction &I : BB) {
3587       writeInstruction(I, InstID, Vals);
3588 
3589       if (!I.getType()->isVoidTy())
3590         ++InstID;
3591 
3592       // If the instruction has metadata, write a metadata attachment later.
3593       NeedsMetadataAttachment |= I.hasMetadataOtherThanDebugLoc();
3594 
3595       // If the instruction has a debug location, emit it.
3596       if (DILocation *DL = I.getDebugLoc()) {
3597         if (DL == LastDL) {
3598           // Just repeat the same debug loc as last time.
3599           Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
3600         } else {
3601           Vals.push_back(DL->getLine());
3602           Vals.push_back(DL->getColumn());
3603           Vals.push_back(VE.getMetadataOrNullID(DL->getScope()));
3604           Vals.push_back(VE.getMetadataOrNullID(DL->getInlinedAt()));
3605           Vals.push_back(DL->isImplicitCode());
3606           Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
3607           Vals.clear();
3608           LastDL = DL;
3609         }
3610       }
3611 
3612       // If the instruction has DbgRecords attached to it, emit them. Note that
3613       // they come after the instruction so that it's easy to attach them again
3614       // when reading the bitcode, even though conceptually the debug locations
3615       // start "before" the instruction.
3616       if (I.hasDbgRecords() && WriteNewDbgInfoFormatToBitcode) {
3617         /// Try to push the value only (unwrapped), otherwise push the
3618         /// metadata wrapped value. Returns true if the value was pushed
3619         /// without the ValueAsMetadata wrapper.
3620         auto PushValueOrMetadata = [&Vals, InstID,
3621                                     this](Metadata *RawLocation) {
3622           assert(RawLocation &&
3623                  "RawLocation unexpectedly null in DbgVariableRecord");
3624           if (ValueAsMetadata *VAM = dyn_cast<ValueAsMetadata>(RawLocation)) {
3625             SmallVector<unsigned, 2> ValAndType;
3626             // If the value is a fwd-ref the type is also pushed. We don't
3627             // want the type, so fwd-refs are kept wrapped (pushValueAndType
3628             // returns false if the value is pushed without type).
3629             if (!pushValueAndType(VAM->getValue(), InstID, ValAndType)) {
3630               Vals.push_back(ValAndType[0]);
3631               return true;
3632             }
3633           }
3634           // The metadata is a DIArgList, or ValueAsMetadata wrapping a
3635           // fwd-ref. Push the metadata ID.
3636           Vals.push_back(VE.getMetadataID(RawLocation));
3637           return false;
3638         };
3639 
3640         // Write out non-instruction debug information attached to this
3641         // instruction. Write it after the instruction so that it's easy to
3642         // re-attach to the instruction reading the records in.
3643         for (DbgRecord &DR : I.DebugMarker->getDbgRecordRange()) {
3644           if (DbgLabelRecord *DLR = dyn_cast<DbgLabelRecord>(&DR)) {
3645             Vals.push_back(VE.getMetadataID(&*DLR->getDebugLoc()));
3646             Vals.push_back(VE.getMetadataID(DLR->getLabel()));
3647             Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_RECORD_LABEL, Vals);
3648             Vals.clear();
3649             continue;
3650           }
3651 
3652           // First 3 fields are common to all kinds:
3653           //   DILocation, DILocalVariable, DIExpression
3654           // dbg_value (FUNC_CODE_DEBUG_RECORD_VALUE)
3655           //   ..., LocationMetadata
3656           // dbg_value (FUNC_CODE_DEBUG_RECORD_VALUE_SIMPLE - abbrev'd)
3657           //   ..., Value
3658           // dbg_declare (FUNC_CODE_DEBUG_RECORD_DECLARE)
3659           //   ..., LocationMetadata
3660           // dbg_assign (FUNC_CODE_DEBUG_RECORD_ASSIGN)
3661           //   ..., LocationMetadata, DIAssignID, DIExpression, LocationMetadata
3662           DbgVariableRecord &DVR = cast<DbgVariableRecord>(DR);
3663           Vals.push_back(VE.getMetadataID(&*DVR.getDebugLoc()));
3664           Vals.push_back(VE.getMetadataID(DVR.getVariable()));
3665           Vals.push_back(VE.getMetadataID(DVR.getExpression()));
3666           if (DVR.isDbgValue()) {
3667             if (PushValueOrMetadata(DVR.getRawLocation()))
3668               Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_RECORD_VALUE_SIMPLE, Vals,
3669                                 FUNCTION_DEBUG_RECORD_VALUE_ABBREV);
3670             else
3671               Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_RECORD_VALUE, Vals);
3672           } else if (DVR.isDbgDeclare()) {
3673             Vals.push_back(VE.getMetadataID(DVR.getRawLocation()));
3674             Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_RECORD_DECLARE, Vals);
3675           } else {
3676             assert(DVR.isDbgAssign() && "Unexpected DbgRecord kind");
3677             Vals.push_back(VE.getMetadataID(DVR.getRawLocation()));
3678             Vals.push_back(VE.getMetadataID(DVR.getAssignID()));
3679             Vals.push_back(VE.getMetadataID(DVR.getAddressExpression()));
3680             Vals.push_back(VE.getMetadataID(DVR.getRawAddress()));
3681             Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_RECORD_ASSIGN, Vals);
3682           }
3683           Vals.clear();
3684         }
3685       }
3686     }
3687 
3688     if (BlockAddress *BA = BlockAddress::lookup(&BB)) {
3689       SmallVector<Value *> Worklist{BA};
3690       SmallPtrSet<Value *, 8> Visited{BA};
3691       while (!Worklist.empty()) {
3692         Value *V = Worklist.pop_back_val();
3693         for (User *U : V->users()) {
3694           if (auto *I = dyn_cast<Instruction>(U)) {
3695             Function *P = I->getFunction();
3696             if (P != &F)
3697               BlockAddressUsers.insert(P);
3698           } else if (isa<Constant>(U) && !isa<GlobalValue>(U) &&
3699                      Visited.insert(U).second)
3700             Worklist.push_back(U);
3701         }
3702       }
3703     }
3704   }
3705 
3706   if (!BlockAddressUsers.empty()) {
3707     Vals.resize(BlockAddressUsers.size());
3708     for (auto I : llvm::enumerate(BlockAddressUsers))
3709       Vals[I.index()] = VE.getValueID(I.value());
3710     Stream.EmitRecord(bitc::FUNC_CODE_BLOCKADDR_USERS, Vals);
3711     Vals.clear();
3712   }
3713 
3714   // Emit names for all the instructions etc.
3715   if (auto *Symtab = F.getValueSymbolTable())
3716     writeFunctionLevelValueSymbolTable(*Symtab);
3717 
3718   if (NeedsMetadataAttachment)
3719     writeFunctionMetadataAttachment(F);
3720   if (VE.shouldPreserveUseListOrder())
3721     writeUseListBlock(&F);
3722   VE.purgeFunction();
3723   Stream.ExitBlock();
3724 }
3725 
3726 // Emit blockinfo, which defines the standard abbreviations etc.
3727 void ModuleBitcodeWriter::writeBlockInfo() {
3728   // We only want to emit block info records for blocks that have multiple
3729   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
3730   // Other blocks can define their abbrevs inline.
3731   Stream.EnterBlockInfoBlock();
3732 
3733   { // 8-bit fixed-width VST_CODE_ENTRY/VST_CODE_BBENTRY strings.
3734     auto Abbv = std::make_shared<BitCodeAbbrev>();
3735     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
3736     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3737     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3738     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3739     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3740         VST_ENTRY_8_ABBREV)
3741       llvm_unreachable("Unexpected abbrev ordering!");
3742   }
3743 
3744   { // 7-bit fixed width VST_CODE_ENTRY strings.
3745     auto Abbv = std::make_shared<BitCodeAbbrev>();
3746     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3747     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3748     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3749     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3750     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3751         VST_ENTRY_7_ABBREV)
3752       llvm_unreachable("Unexpected abbrev ordering!");
3753   }
3754   { // 6-bit char6 VST_CODE_ENTRY strings.
3755     auto Abbv = std::make_shared<BitCodeAbbrev>();
3756     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3757     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3758     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3759     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3760     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3761         VST_ENTRY_6_ABBREV)
3762       llvm_unreachable("Unexpected abbrev ordering!");
3763   }
3764   { // 6-bit char6 VST_CODE_BBENTRY strings.
3765     auto Abbv = std::make_shared<BitCodeAbbrev>();
3766     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
3767     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3768     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3769     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3770     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3771         VST_BBENTRY_6_ABBREV)
3772       llvm_unreachable("Unexpected abbrev ordering!");
3773   }
3774 
3775   { // SETTYPE abbrev for CONSTANTS_BLOCK.
3776     auto Abbv = std::make_shared<BitCodeAbbrev>();
3777     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
3778     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
3779                               VE.computeBitsRequiredForTypeIndices()));
3780     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3781         CONSTANTS_SETTYPE_ABBREV)
3782       llvm_unreachable("Unexpected abbrev ordering!");
3783   }
3784 
3785   { // INTEGER abbrev for CONSTANTS_BLOCK.
3786     auto Abbv = std::make_shared<BitCodeAbbrev>();
3787     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
3788     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3789     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3790         CONSTANTS_INTEGER_ABBREV)
3791       llvm_unreachable("Unexpected abbrev ordering!");
3792   }
3793 
3794   { // CE_CAST abbrev for CONSTANTS_BLOCK.
3795     auto Abbv = std::make_shared<BitCodeAbbrev>();
3796     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
3797     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
3798     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
3799                               VE.computeBitsRequiredForTypeIndices()));
3800     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
3801 
3802     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3803         CONSTANTS_CE_CAST_Abbrev)
3804       llvm_unreachable("Unexpected abbrev ordering!");
3805   }
3806   { // NULL abbrev for CONSTANTS_BLOCK.
3807     auto Abbv = std::make_shared<BitCodeAbbrev>();
3808     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
3809     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3810         CONSTANTS_NULL_Abbrev)
3811       llvm_unreachable("Unexpected abbrev ordering!");
3812   }
3813 
3814   // FIXME: This should only use space for first class types!
3815 
3816   { // INST_LOAD abbrev for FUNCTION_BLOCK.
3817     auto Abbv = std::make_shared<BitCodeAbbrev>();
3818     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
3819     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
3820     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
3821                               VE.computeBitsRequiredForTypeIndices()));
3822     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
3823     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
3824     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3825         FUNCTION_INST_LOAD_ABBREV)
3826       llvm_unreachable("Unexpected abbrev ordering!");
3827   }
3828   { // INST_UNOP abbrev for FUNCTION_BLOCK.
3829     auto Abbv = std::make_shared<BitCodeAbbrev>();
3830     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3831     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3832     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3833     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3834         FUNCTION_INST_UNOP_ABBREV)
3835       llvm_unreachable("Unexpected abbrev ordering!");
3836   }
3837   { // INST_UNOP_FLAGS abbrev for FUNCTION_BLOCK.
3838     auto Abbv = std::make_shared<BitCodeAbbrev>();
3839     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3840     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3841     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3842     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3843     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3844         FUNCTION_INST_UNOP_FLAGS_ABBREV)
3845       llvm_unreachable("Unexpected abbrev ordering!");
3846   }
3847   { // INST_BINOP abbrev for FUNCTION_BLOCK.
3848     auto Abbv = std::make_shared<BitCodeAbbrev>();
3849     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3850     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3851     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3852     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3853     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3854         FUNCTION_INST_BINOP_ABBREV)
3855       llvm_unreachable("Unexpected abbrev ordering!");
3856   }
3857   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
3858     auto Abbv = std::make_shared<BitCodeAbbrev>();
3859     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3860     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3861     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3862     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3863     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3864     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3865         FUNCTION_INST_BINOP_FLAGS_ABBREV)
3866       llvm_unreachable("Unexpected abbrev ordering!");
3867   }
3868   { // INST_CAST abbrev for FUNCTION_BLOCK.
3869     auto Abbv = std::make_shared<BitCodeAbbrev>();
3870     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
3871     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
3872     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
3873                               VE.computeBitsRequiredForTypeIndices()));
3874     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
3875     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3876         FUNCTION_INST_CAST_ABBREV)
3877       llvm_unreachable("Unexpected abbrev ordering!");
3878   }
3879   { // INST_CAST_FLAGS abbrev for FUNCTION_BLOCK.
3880     auto Abbv = std::make_shared<BitCodeAbbrev>();
3881     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
3882     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // OpVal
3883     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
3884                               VE.computeBitsRequiredForTypeIndices()));
3885     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3886     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3887     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3888         FUNCTION_INST_CAST_FLAGS_ABBREV)
3889       llvm_unreachable("Unexpected abbrev ordering!");
3890   }
3891 
3892   { // INST_RET abbrev for FUNCTION_BLOCK.
3893     auto Abbv = std::make_shared<BitCodeAbbrev>();
3894     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3895     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3896         FUNCTION_INST_RET_VOID_ABBREV)
3897       llvm_unreachable("Unexpected abbrev ordering!");
3898   }
3899   { // INST_RET abbrev for FUNCTION_BLOCK.
3900     auto Abbv = std::make_shared<BitCodeAbbrev>();
3901     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3902     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
3903     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3904         FUNCTION_INST_RET_VAL_ABBREV)
3905       llvm_unreachable("Unexpected abbrev ordering!");
3906   }
3907   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
3908     auto Abbv = std::make_shared<BitCodeAbbrev>();
3909     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
3910     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3911         FUNCTION_INST_UNREACHABLE_ABBREV)
3912       llvm_unreachable("Unexpected abbrev ordering!");
3913   }
3914   {
3915     auto Abbv = std::make_shared<BitCodeAbbrev>();
3916     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_GEP));
3917     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
3918     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, // dest ty
3919                               Log2_32_Ceil(VE.getTypes().size() + 1)));
3920     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3921     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
3922     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3923         FUNCTION_INST_GEP_ABBREV)
3924       llvm_unreachable("Unexpected abbrev ordering!");
3925   }
3926   {
3927     auto Abbv = std::make_shared<BitCodeAbbrev>();
3928     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_DEBUG_RECORD_VALUE_SIMPLE));
3929     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 7)); // dbgloc
3930     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 7)); // var
3931     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 7)); // expr
3932     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // val
3933     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3934         FUNCTION_DEBUG_RECORD_VALUE_ABBREV)
3935       llvm_unreachable("Unexpected abbrev ordering! 1");
3936   }
3937   Stream.ExitBlock();
3938 }
3939 
3940 /// Write the module path strings, currently only used when generating
3941 /// a combined index file.
3942 void IndexBitcodeWriter::writeModStrings() {
3943   Stream.EnterSubblock(bitc::MODULE_STRTAB_BLOCK_ID, 3);
3944 
3945   // TODO: See which abbrev sizes we actually need to emit
3946 
3947   // 8-bit fixed-width MST_ENTRY strings.
3948   auto Abbv = std::make_shared<BitCodeAbbrev>();
3949   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3950   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3951   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3952   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3953   unsigned Abbrev8Bit = Stream.EmitAbbrev(std::move(Abbv));
3954 
3955   // 7-bit fixed width MST_ENTRY strings.
3956   Abbv = std::make_shared<BitCodeAbbrev>();
3957   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3958   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3959   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3960   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3961   unsigned Abbrev7Bit = Stream.EmitAbbrev(std::move(Abbv));
3962 
3963   // 6-bit char6 MST_ENTRY strings.
3964   Abbv = std::make_shared<BitCodeAbbrev>();
3965   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3966   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3967   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3968   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3969   unsigned Abbrev6Bit = Stream.EmitAbbrev(std::move(Abbv));
3970 
3971   // Module Hash, 160 bits SHA1. Optionally, emitted after each MST_CODE_ENTRY.
3972   Abbv = std::make_shared<BitCodeAbbrev>();
3973   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_HASH));
3974   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3975   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3976   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3977   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3978   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3979   unsigned AbbrevHash = Stream.EmitAbbrev(std::move(Abbv));
3980 
3981   SmallVector<unsigned, 64> Vals;
3982   forEachModule([&](const StringMapEntry<ModuleHash> &MPSE) {
3983     StringRef Key = MPSE.getKey();
3984     const auto &Hash = MPSE.getValue();
3985     StringEncoding Bits = getStringEncoding(Key);
3986     unsigned AbbrevToUse = Abbrev8Bit;
3987     if (Bits == SE_Char6)
3988       AbbrevToUse = Abbrev6Bit;
3989     else if (Bits == SE_Fixed7)
3990       AbbrevToUse = Abbrev7Bit;
3991 
3992     auto ModuleId = ModuleIdMap.size();
3993     ModuleIdMap[Key] = ModuleId;
3994     Vals.push_back(ModuleId);
3995     Vals.append(Key.begin(), Key.end());
3996 
3997     // Emit the finished record.
3998     Stream.EmitRecord(bitc::MST_CODE_ENTRY, Vals, AbbrevToUse);
3999 
4000     // Emit an optional hash for the module now
4001     if (llvm::any_of(Hash, [](uint32_t H) { return H; })) {
4002       Vals.assign(Hash.begin(), Hash.end());
4003       // Emit the hash record.
4004       Stream.EmitRecord(bitc::MST_CODE_HASH, Vals, AbbrevHash);
4005     }
4006 
4007     Vals.clear();
4008   });
4009   Stream.ExitBlock();
4010 }
4011 
4012 /// Write the function type metadata related records that need to appear before
4013 /// a function summary entry (whether per-module or combined).
4014 template <typename Fn>
4015 static void writeFunctionTypeMetadataRecords(BitstreamWriter &Stream,
4016                                              FunctionSummary *FS,
4017                                              Fn GetValueID) {
4018   if (!FS->type_tests().empty())
4019     Stream.EmitRecord(bitc::FS_TYPE_TESTS, FS->type_tests());
4020 
4021   SmallVector<uint64_t, 64> Record;
4022 
4023   auto WriteVFuncIdVec = [&](uint64_t Ty,
4024                              ArrayRef<FunctionSummary::VFuncId> VFs) {
4025     if (VFs.empty())
4026       return;
4027     Record.clear();
4028     for (auto &VF : VFs) {
4029       Record.push_back(VF.GUID);
4030       Record.push_back(VF.Offset);
4031     }
4032     Stream.EmitRecord(Ty, Record);
4033   };
4034 
4035   WriteVFuncIdVec(bitc::FS_TYPE_TEST_ASSUME_VCALLS,
4036                   FS->type_test_assume_vcalls());
4037   WriteVFuncIdVec(bitc::FS_TYPE_CHECKED_LOAD_VCALLS,
4038                   FS->type_checked_load_vcalls());
4039 
4040   auto WriteConstVCallVec = [&](uint64_t Ty,
4041                                 ArrayRef<FunctionSummary::ConstVCall> VCs) {
4042     for (auto &VC : VCs) {
4043       Record.clear();
4044       Record.push_back(VC.VFunc.GUID);
4045       Record.push_back(VC.VFunc.Offset);
4046       llvm::append_range(Record, VC.Args);
4047       Stream.EmitRecord(Ty, Record);
4048     }
4049   };
4050 
4051   WriteConstVCallVec(bitc::FS_TYPE_TEST_ASSUME_CONST_VCALL,
4052                      FS->type_test_assume_const_vcalls());
4053   WriteConstVCallVec(bitc::FS_TYPE_CHECKED_LOAD_CONST_VCALL,
4054                      FS->type_checked_load_const_vcalls());
4055 
4056   auto WriteRange = [&](ConstantRange Range) {
4057     Range = Range.sextOrTrunc(FunctionSummary::ParamAccess::RangeWidth);
4058     assert(Range.getLower().getNumWords() == 1);
4059     assert(Range.getUpper().getNumWords() == 1);
4060     emitSignedInt64(Record, *Range.getLower().getRawData());
4061     emitSignedInt64(Record, *Range.getUpper().getRawData());
4062   };
4063 
4064   if (!FS->paramAccesses().empty()) {
4065     Record.clear();
4066     for (auto &Arg : FS->paramAccesses()) {
4067       size_t UndoSize = Record.size();
4068       Record.push_back(Arg.ParamNo);
4069       WriteRange(Arg.Use);
4070       Record.push_back(Arg.Calls.size());
4071       for (auto &Call : Arg.Calls) {
4072         Record.push_back(Call.ParamNo);
4073         std::optional<unsigned> ValueID = GetValueID(Call.Callee);
4074         if (!ValueID) {
4075           // If ValueID is unknown we can't drop just this call, we must drop
4076           // entire parameter.
4077           Record.resize(UndoSize);
4078           break;
4079         }
4080         Record.push_back(*ValueID);
4081         WriteRange(Call.Offsets);
4082       }
4083     }
4084     if (!Record.empty())
4085       Stream.EmitRecord(bitc::FS_PARAM_ACCESS, Record);
4086   }
4087 }
4088 
4089 /// Collect type IDs from type tests used by function.
4090 static void
4091 getReferencedTypeIds(FunctionSummary *FS,
4092                      std::set<GlobalValue::GUID> &ReferencedTypeIds) {
4093   if (!FS->type_tests().empty())
4094     for (auto &TT : FS->type_tests())
4095       ReferencedTypeIds.insert(TT);
4096 
4097   auto GetReferencedTypesFromVFuncIdVec =
4098       [&](ArrayRef<FunctionSummary::VFuncId> VFs) {
4099         for (auto &VF : VFs)
4100           ReferencedTypeIds.insert(VF.GUID);
4101       };
4102 
4103   GetReferencedTypesFromVFuncIdVec(FS->type_test_assume_vcalls());
4104   GetReferencedTypesFromVFuncIdVec(FS->type_checked_load_vcalls());
4105 
4106   auto GetReferencedTypesFromConstVCallVec =
4107       [&](ArrayRef<FunctionSummary::ConstVCall> VCs) {
4108         for (auto &VC : VCs)
4109           ReferencedTypeIds.insert(VC.VFunc.GUID);
4110       };
4111 
4112   GetReferencedTypesFromConstVCallVec(FS->type_test_assume_const_vcalls());
4113   GetReferencedTypesFromConstVCallVec(FS->type_checked_load_const_vcalls());
4114 }
4115 
4116 static void writeWholeProgramDevirtResolutionByArg(
4117     SmallVector<uint64_t, 64> &NameVals, const std::vector<uint64_t> &args,
4118     const WholeProgramDevirtResolution::ByArg &ByArg) {
4119   NameVals.push_back(args.size());
4120   llvm::append_range(NameVals, args);
4121 
4122   NameVals.push_back(ByArg.TheKind);
4123   NameVals.push_back(ByArg.Info);
4124   NameVals.push_back(ByArg.Byte);
4125   NameVals.push_back(ByArg.Bit);
4126 }
4127 
4128 static void writeWholeProgramDevirtResolution(
4129     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
4130     uint64_t Id, const WholeProgramDevirtResolution &Wpd) {
4131   NameVals.push_back(Id);
4132 
4133   NameVals.push_back(Wpd.TheKind);
4134   NameVals.push_back(StrtabBuilder.add(Wpd.SingleImplName));
4135   NameVals.push_back(Wpd.SingleImplName.size());
4136 
4137   NameVals.push_back(Wpd.ResByArg.size());
4138   for (auto &A : Wpd.ResByArg)
4139     writeWholeProgramDevirtResolutionByArg(NameVals, A.first, A.second);
4140 }
4141 
4142 static void writeTypeIdSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
4143                                      StringTableBuilder &StrtabBuilder,
4144                                      const std::string &Id,
4145                                      const TypeIdSummary &Summary) {
4146   NameVals.push_back(StrtabBuilder.add(Id));
4147   NameVals.push_back(Id.size());
4148 
4149   NameVals.push_back(Summary.TTRes.TheKind);
4150   NameVals.push_back(Summary.TTRes.SizeM1BitWidth);
4151   NameVals.push_back(Summary.TTRes.AlignLog2);
4152   NameVals.push_back(Summary.TTRes.SizeM1);
4153   NameVals.push_back(Summary.TTRes.BitMask);
4154   NameVals.push_back(Summary.TTRes.InlineBits);
4155 
4156   for (auto &W : Summary.WPDRes)
4157     writeWholeProgramDevirtResolution(NameVals, StrtabBuilder, W.first,
4158                                       W.second);
4159 }
4160 
4161 static void writeTypeIdCompatibleVtableSummaryRecord(
4162     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
4163     const std::string &Id, const TypeIdCompatibleVtableInfo &Summary,
4164     ValueEnumerator &VE) {
4165   NameVals.push_back(StrtabBuilder.add(Id));
4166   NameVals.push_back(Id.size());
4167 
4168   for (auto &P : Summary) {
4169     NameVals.push_back(P.AddressPointOffset);
4170     NameVals.push_back(VE.getValueID(P.VTableVI.getValue()));
4171   }
4172 }
4173 
4174 static void writeFunctionHeapProfileRecords(
4175     BitstreamWriter &Stream, FunctionSummary *FS, unsigned CallsiteAbbrev,
4176     unsigned AllocAbbrev, bool PerModule,
4177     std::function<unsigned(const ValueInfo &VI)> GetValueID,
4178     std::function<unsigned(unsigned)> GetStackIndex) {
4179   SmallVector<uint64_t> Record;
4180 
4181   for (auto &CI : FS->callsites()) {
4182     Record.clear();
4183     // Per module callsite clones should always have a single entry of
4184     // value 0.
4185     assert(!PerModule || (CI.Clones.size() == 1 && CI.Clones[0] == 0));
4186     Record.push_back(GetValueID(CI.Callee));
4187     if (!PerModule) {
4188       Record.push_back(CI.StackIdIndices.size());
4189       Record.push_back(CI.Clones.size());
4190     }
4191     for (auto Id : CI.StackIdIndices)
4192       Record.push_back(GetStackIndex(Id));
4193     if (!PerModule) {
4194       for (auto V : CI.Clones)
4195         Record.push_back(V);
4196     }
4197     Stream.EmitRecord(PerModule ? bitc::FS_PERMODULE_CALLSITE_INFO
4198                                 : bitc::FS_COMBINED_CALLSITE_INFO,
4199                       Record, CallsiteAbbrev);
4200   }
4201 
4202   for (auto &AI : FS->allocs()) {
4203     Record.clear();
4204     // Per module alloc versions should always have a single entry of
4205     // value 0.
4206     assert(!PerModule || (AI.Versions.size() == 1 && AI.Versions[0] == 0));
4207     Record.push_back(AI.MIBs.size());
4208     if (!PerModule)
4209       Record.push_back(AI.Versions.size());
4210     for (auto &MIB : AI.MIBs) {
4211       Record.push_back((uint8_t)MIB.AllocType);
4212       Record.push_back(MIB.StackIdIndices.size());
4213       for (auto Id : MIB.StackIdIndices)
4214         Record.push_back(GetStackIndex(Id));
4215     }
4216     if (!PerModule) {
4217       for (auto V : AI.Versions)
4218         Record.push_back(V);
4219     }
4220     assert(AI.TotalSizes.empty() || AI.TotalSizes.size() == AI.MIBs.size());
4221     if (!AI.TotalSizes.empty()) {
4222       for (auto Size : AI.TotalSizes)
4223         Record.push_back(Size);
4224     }
4225     Stream.EmitRecord(PerModule ? bitc::FS_PERMODULE_ALLOC_INFO
4226                                 : bitc::FS_COMBINED_ALLOC_INFO,
4227                       Record, AllocAbbrev);
4228   }
4229 }
4230 
4231 // Helper to emit a single function summary record.
4232 void ModuleBitcodeWriterBase::writePerModuleFunctionSummaryRecord(
4233     SmallVector<uint64_t, 64> &NameVals, GlobalValueSummary *Summary,
4234     unsigned ValueID, unsigned FSCallsRelBFAbbrev,
4235     unsigned FSCallsProfileAbbrev, unsigned CallsiteAbbrev,
4236     unsigned AllocAbbrev, const Function &F) {
4237   NameVals.push_back(ValueID);
4238 
4239   FunctionSummary *FS = cast<FunctionSummary>(Summary);
4240 
4241   writeFunctionTypeMetadataRecords(
4242       Stream, FS, [&](const ValueInfo &VI) -> std::optional<unsigned> {
4243         return {VE.getValueID(VI.getValue())};
4244       });
4245 
4246   writeFunctionHeapProfileRecords(
4247       Stream, FS, CallsiteAbbrev, AllocAbbrev,
4248       /*PerModule*/ true,
4249       /*GetValueId*/ [&](const ValueInfo &VI) { return getValueId(VI); },
4250       /*GetStackIndex*/ [&](unsigned I) { return I; });
4251 
4252   auto SpecialRefCnts = FS->specialRefCounts();
4253   NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
4254   NameVals.push_back(FS->instCount());
4255   NameVals.push_back(getEncodedFFlags(FS->fflags()));
4256   NameVals.push_back(FS->refs().size());
4257   NameVals.push_back(SpecialRefCnts.first);  // rorefcnt
4258   NameVals.push_back(SpecialRefCnts.second); // worefcnt
4259 
4260   for (auto &RI : FS->refs())
4261     NameVals.push_back(getValueId(RI));
4262 
4263   const bool UseRelBFRecord =
4264       WriteRelBFToSummary && !F.hasProfileData() &&
4265       ForceSummaryEdgesCold == FunctionSummary::FSHT_None;
4266   for (auto &ECI : FS->calls()) {
4267     NameVals.push_back(getValueId(ECI.first));
4268     if (UseRelBFRecord)
4269       NameVals.push_back(getEncodedRelBFCallEdgeInfo(ECI.second));
4270     else
4271       NameVals.push_back(getEncodedHotnessCallEdgeInfo(ECI.second));
4272   }
4273 
4274   unsigned FSAbbrev =
4275       (UseRelBFRecord ? FSCallsRelBFAbbrev : FSCallsProfileAbbrev);
4276   unsigned Code =
4277       (UseRelBFRecord ? bitc::FS_PERMODULE_RELBF : bitc::FS_PERMODULE_PROFILE);
4278 
4279   // Emit the finished record.
4280   Stream.EmitRecord(Code, NameVals, FSAbbrev);
4281   NameVals.clear();
4282 }
4283 
4284 // Collect the global value references in the given variable's initializer,
4285 // and emit them in a summary record.
4286 void ModuleBitcodeWriterBase::writeModuleLevelReferences(
4287     const GlobalVariable &V, SmallVector<uint64_t, 64> &NameVals,
4288     unsigned FSModRefsAbbrev, unsigned FSModVTableRefsAbbrev) {
4289   auto VI = Index->getValueInfo(V.getGUID());
4290   if (!VI || VI.getSummaryList().empty()) {
4291     // Only declarations should not have a summary (a declaration might however
4292     // have a summary if the def was in module level asm).
4293     assert(V.isDeclaration());
4294     return;
4295   }
4296   auto *Summary = VI.getSummaryList()[0].get();
4297   NameVals.push_back(VE.getValueID(&V));
4298   GlobalVarSummary *VS = cast<GlobalVarSummary>(Summary);
4299   NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
4300   NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
4301 
4302   auto VTableFuncs = VS->vTableFuncs();
4303   if (!VTableFuncs.empty())
4304     NameVals.push_back(VS->refs().size());
4305 
4306   unsigned SizeBeforeRefs = NameVals.size();
4307   for (auto &RI : VS->refs())
4308     NameVals.push_back(VE.getValueID(RI.getValue()));
4309   // Sort the refs for determinism output, the vector returned by FS->refs() has
4310   // been initialized from a DenseSet.
4311   llvm::sort(drop_begin(NameVals, SizeBeforeRefs));
4312 
4313   if (VTableFuncs.empty())
4314     Stream.EmitRecord(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS, NameVals,
4315                       FSModRefsAbbrev);
4316   else {
4317     // VTableFuncs pairs should already be sorted by offset.
4318     for (auto &P : VTableFuncs) {
4319       NameVals.push_back(VE.getValueID(P.FuncVI.getValue()));
4320       NameVals.push_back(P.VTableOffset);
4321     }
4322 
4323     Stream.EmitRecord(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS, NameVals,
4324                       FSModVTableRefsAbbrev);
4325   }
4326   NameVals.clear();
4327 }
4328 
4329 /// Emit the per-module summary section alongside the rest of
4330 /// the module's bitcode.
4331 void ModuleBitcodeWriterBase::writePerModuleGlobalValueSummary() {
4332   // By default we compile with ThinLTO if the module has a summary, but the
4333   // client can request full LTO with a module flag.
4334   bool IsThinLTO = true;
4335   if (auto *MD =
4336           mdconst::extract_or_null<ConstantInt>(M.getModuleFlag("ThinLTO")))
4337     IsThinLTO = MD->getZExtValue();
4338   Stream.EnterSubblock(IsThinLTO ? bitc::GLOBALVAL_SUMMARY_BLOCK_ID
4339                                  : bitc::FULL_LTO_GLOBALVAL_SUMMARY_BLOCK_ID,
4340                        4);
4341 
4342   Stream.EmitRecord(
4343       bitc::FS_VERSION,
4344       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
4345 
4346   // Write the index flags.
4347   uint64_t Flags = 0;
4348   // Bits 1-3 are set only in the combined index, skip them.
4349   if (Index->enableSplitLTOUnit())
4350     Flags |= 0x8;
4351   if (Index->hasUnifiedLTO())
4352     Flags |= 0x200;
4353 
4354   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Flags});
4355 
4356   if (Index->begin() == Index->end()) {
4357     Stream.ExitBlock();
4358     return;
4359   }
4360 
4361   auto Abbv = std::make_shared<BitCodeAbbrev>();
4362   Abbv->Add(BitCodeAbbrevOp(bitc::FS_VALUE_GUID));
4363   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
4364   // GUIDS often use up most of 64-bits, so encode as two Fixed 32.
4365   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
4366   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
4367   unsigned ValueGuidAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4368 
4369   for (const auto &GVI : valueIds()) {
4370     Stream.EmitRecord(bitc::FS_VALUE_GUID,
4371                       ArrayRef<uint32_t>{GVI.second,
4372                                          static_cast<uint32_t>(GVI.first >> 32),
4373                                          static_cast<uint32_t>(GVI.first)},
4374                       ValueGuidAbbrev);
4375   }
4376 
4377   if (!Index->stackIds().empty()) {
4378     auto StackIdAbbv = std::make_shared<BitCodeAbbrev>();
4379     StackIdAbbv->Add(BitCodeAbbrevOp(bitc::FS_STACK_IDS));
4380     // numids x stackid
4381     StackIdAbbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4382     StackIdAbbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4383     unsigned StackIdAbbvId = Stream.EmitAbbrev(std::move(StackIdAbbv));
4384     Stream.EmitRecord(bitc::FS_STACK_IDS, Index->stackIds(), StackIdAbbvId);
4385   }
4386 
4387   // Abbrev for FS_PERMODULE_PROFILE.
4388   Abbv = std::make_shared<BitCodeAbbrev>();
4389   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_PROFILE));
4390   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4391   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // flags
4392   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4393   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4394   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4395   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4396   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4397   // numrefs x valueid, n x (valueid, hotness+tailcall flags)
4398   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4399   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4400   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4401 
4402   // Abbrev for FS_PERMODULE_RELBF.
4403   Abbv = std::make_shared<BitCodeAbbrev>();
4404   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_RELBF));
4405   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4406   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4407   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4408   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4409   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4410   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4411   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4412   // numrefs x valueid, n x (valueid, rel_block_freq+tailcall])
4413   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4414   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4415   unsigned FSCallsRelBFAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4416 
4417   // Abbrev for FS_PERMODULE_GLOBALVAR_INIT_REFS.
4418   Abbv = std::make_shared<BitCodeAbbrev>();
4419   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS));
4420   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
4421   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
4422   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));  // valueids
4423   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4424   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4425 
4426   // Abbrev for FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS.
4427   Abbv = std::make_shared<BitCodeAbbrev>();
4428   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS));
4429   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
4430   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
4431   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numrefs
4432   // numrefs x valueid, n x (valueid , offset)
4433   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4434   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4435   unsigned FSModVTableRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4436 
4437   // Abbrev for FS_ALIAS.
4438   Abbv = std::make_shared<BitCodeAbbrev>();
4439   Abbv->Add(BitCodeAbbrevOp(bitc::FS_ALIAS));
4440   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4441   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4442   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4443   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4444 
4445   // Abbrev for FS_TYPE_ID_METADATA
4446   Abbv = std::make_shared<BitCodeAbbrev>();
4447   Abbv->Add(BitCodeAbbrevOp(bitc::FS_TYPE_ID_METADATA));
4448   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid strtab index
4449   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid length
4450   // n x (valueid , offset)
4451   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4452   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4453   unsigned TypeIdCompatibleVtableAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4454 
4455   Abbv = std::make_shared<BitCodeAbbrev>();
4456   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_CALLSITE_INFO));
4457   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
4458   // n x stackidindex
4459   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4460   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4461   unsigned CallsiteAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4462 
4463   Abbv = std::make_shared<BitCodeAbbrev>();
4464   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_ALLOC_INFO));
4465   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // nummib
4466   // n x (alloc type, numstackids, numstackids x stackidindex)
4467   // optional: nummib x total size
4468   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4469   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4470   unsigned AllocAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4471 
4472   SmallVector<uint64_t, 64> NameVals;
4473   // Iterate over the list of functions instead of the Index to
4474   // ensure the ordering is stable.
4475   for (const Function &F : M) {
4476     // Summary emission does not support anonymous functions, they have to
4477     // renamed using the anonymous function renaming pass.
4478     if (!F.hasName())
4479       report_fatal_error("Unexpected anonymous function when writing summary");
4480 
4481     ValueInfo VI = Index->getValueInfo(F.getGUID());
4482     if (!VI || VI.getSummaryList().empty()) {
4483       // Only declarations should not have a summary (a declaration might
4484       // however have a summary if the def was in module level asm).
4485       assert(F.isDeclaration());
4486       continue;
4487     }
4488     auto *Summary = VI.getSummaryList()[0].get();
4489     writePerModuleFunctionSummaryRecord(
4490         NameVals, Summary, VE.getValueID(&F), FSCallsRelBFAbbrev,
4491         FSCallsProfileAbbrev, CallsiteAbbrev, AllocAbbrev, F);
4492   }
4493 
4494   // Capture references from GlobalVariable initializers, which are outside
4495   // of a function scope.
4496   for (const GlobalVariable &G : M.globals())
4497     writeModuleLevelReferences(G, NameVals, FSModRefsAbbrev,
4498                                FSModVTableRefsAbbrev);
4499 
4500   for (const GlobalAlias &A : M.aliases()) {
4501     auto *Aliasee = A.getAliaseeObject();
4502     // Skip ifunc and nameless functions which don't have an entry in the
4503     // summary.
4504     if (!Aliasee->hasName() || isa<GlobalIFunc>(Aliasee))
4505       continue;
4506     auto AliasId = VE.getValueID(&A);
4507     auto AliaseeId = VE.getValueID(Aliasee);
4508     NameVals.push_back(AliasId);
4509     auto *Summary = Index->getGlobalValueSummary(A);
4510     AliasSummary *AS = cast<AliasSummary>(Summary);
4511     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
4512     NameVals.push_back(AliaseeId);
4513     Stream.EmitRecord(bitc::FS_ALIAS, NameVals, FSAliasAbbrev);
4514     NameVals.clear();
4515   }
4516 
4517   for (auto &S : Index->typeIdCompatibleVtableMap()) {
4518     writeTypeIdCompatibleVtableSummaryRecord(NameVals, StrtabBuilder, S.first,
4519                                              S.second, VE);
4520     Stream.EmitRecord(bitc::FS_TYPE_ID_METADATA, NameVals,
4521                       TypeIdCompatibleVtableAbbrev);
4522     NameVals.clear();
4523   }
4524 
4525   if (Index->getBlockCount())
4526     Stream.EmitRecord(bitc::FS_BLOCK_COUNT,
4527                       ArrayRef<uint64_t>{Index->getBlockCount()});
4528 
4529   Stream.ExitBlock();
4530 }
4531 
4532 /// Emit the combined summary section into the combined index file.
4533 void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
4534   Stream.EnterSubblock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID, 4);
4535   Stream.EmitRecord(
4536       bitc::FS_VERSION,
4537       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
4538 
4539   // Write the index flags.
4540   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Index.getFlags()});
4541 
4542   auto Abbv = std::make_shared<BitCodeAbbrev>();
4543   Abbv->Add(BitCodeAbbrevOp(bitc::FS_VALUE_GUID));
4544   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
4545   // GUIDS often use up most of 64-bits, so encode as two Fixed 32.
4546   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
4547   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
4548   unsigned ValueGuidAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4549 
4550   for (const auto &GVI : valueIds()) {
4551     Stream.EmitRecord(bitc::FS_VALUE_GUID,
4552                       ArrayRef<uint32_t>{GVI.second,
4553                                          static_cast<uint32_t>(GVI.first >> 32),
4554                                          static_cast<uint32_t>(GVI.first)},
4555                       ValueGuidAbbrev);
4556   }
4557 
4558   // Write the stack ids used by this index, which will be a subset of those in
4559   // the full index in the case of distributed indexes.
4560   if (!StackIds.empty()) {
4561     auto StackIdAbbv = std::make_shared<BitCodeAbbrev>();
4562     StackIdAbbv->Add(BitCodeAbbrevOp(bitc::FS_STACK_IDS));
4563     // numids x stackid
4564     StackIdAbbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4565     StackIdAbbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4566     unsigned StackIdAbbvId = Stream.EmitAbbrev(std::move(StackIdAbbv));
4567     Stream.EmitRecord(bitc::FS_STACK_IDS, StackIds, StackIdAbbvId);
4568   }
4569 
4570   // Abbrev for FS_COMBINED_PROFILE.
4571   Abbv = std::make_shared<BitCodeAbbrev>();
4572   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_PROFILE));
4573   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4574   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4575   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4576   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4577   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4578   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
4579   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4580   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4581   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4582   // numrefs x valueid, n x (valueid, hotness+tailcall flags)
4583   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4584   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4585   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4586 
4587   // Abbrev for FS_COMBINED_GLOBALVAR_INIT_REFS.
4588   Abbv = std::make_shared<BitCodeAbbrev>();
4589   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS));
4590   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4591   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4592   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4593   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));    // valueids
4594   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4595   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4596 
4597   // Abbrev for FS_COMBINED_ALIAS.
4598   Abbv = std::make_shared<BitCodeAbbrev>();
4599   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_ALIAS));
4600   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4601   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4602   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4603   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4604   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4605 
4606   Abbv = std::make_shared<BitCodeAbbrev>();
4607   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_CALLSITE_INFO));
4608   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
4609   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numstackindices
4610   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numver
4611   // numstackindices x stackidindex, numver x version
4612   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4613   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4614   unsigned CallsiteAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4615 
4616   Abbv = std::make_shared<BitCodeAbbrev>();
4617   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_ALLOC_INFO));
4618   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // nummib
4619   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numver
4620   // nummib x (alloc type, numstackids, numstackids x stackidindex),
4621   // numver x version
4622   // optional: nummib x total size
4623   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4624   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4625   unsigned AllocAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4626 
4627   auto shouldImportValueAsDecl = [&](GlobalValueSummary *GVS) -> bool {
4628     if (DecSummaries == nullptr)
4629       return false;
4630     return DecSummaries->count(GVS);
4631   };
4632 
4633   // The aliases are emitted as a post-pass, and will point to the value
4634   // id of the aliasee. Save them in a vector for post-processing.
4635   SmallVector<AliasSummary *, 64> Aliases;
4636 
4637   // Save the value id for each summary for alias emission.
4638   DenseMap<const GlobalValueSummary *, unsigned> SummaryToValueIdMap;
4639 
4640   SmallVector<uint64_t, 64> NameVals;
4641 
4642   // Set that will be populated during call to writeFunctionTypeMetadataRecords
4643   // with the type ids referenced by this index file.
4644   std::set<GlobalValue::GUID> ReferencedTypeIds;
4645 
4646   // For local linkage, we also emit the original name separately
4647   // immediately after the record.
4648   auto MaybeEmitOriginalName = [&](GlobalValueSummary &S) {
4649     // We don't need to emit the original name if we are writing the index for
4650     // distributed backends (in which case ModuleToSummariesForIndex is
4651     // non-null). The original name is only needed during the thin link, since
4652     // for SamplePGO the indirect call targets for local functions have
4653     // have the original name annotated in profile.
4654     // Continue to emit it when writing out the entire combined index, which is
4655     // used in testing the thin link via llvm-lto.
4656     if (ModuleToSummariesForIndex || !GlobalValue::isLocalLinkage(S.linkage()))
4657       return;
4658     NameVals.push_back(S.getOriginalName());
4659     Stream.EmitRecord(bitc::FS_COMBINED_ORIGINAL_NAME, NameVals);
4660     NameVals.clear();
4661   };
4662 
4663   DenseSet<GlobalValue::GUID> DefOrUseGUIDs;
4664   forEachSummary([&](GVInfo I, bool IsAliasee) {
4665     GlobalValueSummary *S = I.second;
4666     assert(S);
4667     DefOrUseGUIDs.insert(I.first);
4668     for (const ValueInfo &VI : S->refs())
4669       DefOrUseGUIDs.insert(VI.getGUID());
4670 
4671     auto ValueId = getValueId(I.first);
4672     assert(ValueId);
4673     SummaryToValueIdMap[S] = *ValueId;
4674 
4675     // If this is invoked for an aliasee, we want to record the above
4676     // mapping, but then not emit a summary entry (if the aliasee is
4677     // to be imported, we will invoke this separately with IsAliasee=false).
4678     if (IsAliasee)
4679       return;
4680 
4681     if (auto *AS = dyn_cast<AliasSummary>(S)) {
4682       // Will process aliases as a post-pass because the reader wants all
4683       // global to be loaded first.
4684       Aliases.push_back(AS);
4685       return;
4686     }
4687 
4688     if (auto *VS = dyn_cast<GlobalVarSummary>(S)) {
4689       NameVals.push_back(*ValueId);
4690       assert(ModuleIdMap.count(VS->modulePath()));
4691       NameVals.push_back(ModuleIdMap[VS->modulePath()]);
4692       NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
4693       NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
4694       for (auto &RI : VS->refs()) {
4695         auto RefValueId = getValueId(RI.getGUID());
4696         if (!RefValueId)
4697           continue;
4698         NameVals.push_back(*RefValueId);
4699       }
4700 
4701       // Emit the finished record.
4702       Stream.EmitRecord(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS, NameVals,
4703                         FSModRefsAbbrev);
4704       NameVals.clear();
4705       MaybeEmitOriginalName(*S);
4706       return;
4707     }
4708 
4709     auto GetValueId = [&](const ValueInfo &VI) -> std::optional<unsigned> {
4710       if (!VI)
4711         return std::nullopt;
4712       return getValueId(VI.getGUID());
4713     };
4714 
4715     auto *FS = cast<FunctionSummary>(S);
4716     writeFunctionTypeMetadataRecords(Stream, FS, GetValueId);
4717     getReferencedTypeIds(FS, ReferencedTypeIds);
4718 
4719     writeFunctionHeapProfileRecords(
4720         Stream, FS, CallsiteAbbrev, AllocAbbrev,
4721         /*PerModule*/ false,
4722         /*GetValueId*/
4723         [&](const ValueInfo &VI) -> unsigned {
4724           std::optional<unsigned> ValueID = GetValueId(VI);
4725           // This can happen in shared index files for distributed ThinLTO if
4726           // the callee function summary is not included. Record 0 which we
4727           // will have to deal with conservatively when doing any kind of
4728           // validation in the ThinLTO backends.
4729           if (!ValueID)
4730             return 0;
4731           return *ValueID;
4732         },
4733         /*GetStackIndex*/
4734         [&](unsigned I) {
4735           // Get the corresponding index into the list of StackIds actually
4736           // being written for this combined index (which may be a subset in
4737           // the case of distributed indexes).
4738           assert(StackIdIndicesToIndex.contains(I));
4739           return StackIdIndicesToIndex[I];
4740         });
4741 
4742     NameVals.push_back(*ValueId);
4743     assert(ModuleIdMap.count(FS->modulePath()));
4744     NameVals.push_back(ModuleIdMap[FS->modulePath()]);
4745     NameVals.push_back(
4746         getEncodedGVSummaryFlags(FS->flags(), shouldImportValueAsDecl(FS)));
4747     NameVals.push_back(FS->instCount());
4748     NameVals.push_back(getEncodedFFlags(FS->fflags()));
4749     // TODO: Stop writing entry count and bump bitcode version.
4750     NameVals.push_back(0 /* EntryCount */);
4751 
4752     // Fill in below
4753     NameVals.push_back(0); // numrefs
4754     NameVals.push_back(0); // rorefcnt
4755     NameVals.push_back(0); // worefcnt
4756 
4757     unsigned Count = 0, RORefCnt = 0, WORefCnt = 0;
4758     for (auto &RI : FS->refs()) {
4759       auto RefValueId = getValueId(RI.getGUID());
4760       if (!RefValueId)
4761         continue;
4762       NameVals.push_back(*RefValueId);
4763       if (RI.isReadOnly())
4764         RORefCnt++;
4765       else if (RI.isWriteOnly())
4766         WORefCnt++;
4767       Count++;
4768     }
4769     NameVals[6] = Count;
4770     NameVals[7] = RORefCnt;
4771     NameVals[8] = WORefCnt;
4772 
4773     for (auto &EI : FS->calls()) {
4774       // If this GUID doesn't have a value id, it doesn't have a function
4775       // summary and we don't need to record any calls to it.
4776       std::optional<unsigned> CallValueId = GetValueId(EI.first);
4777       if (!CallValueId)
4778         continue;
4779       NameVals.push_back(*CallValueId);
4780       NameVals.push_back(getEncodedHotnessCallEdgeInfo(EI.second));
4781     }
4782 
4783     // Emit the finished record.
4784     Stream.EmitRecord(bitc::FS_COMBINED_PROFILE, NameVals,
4785                       FSCallsProfileAbbrev);
4786     NameVals.clear();
4787     MaybeEmitOriginalName(*S);
4788   });
4789 
4790   for (auto *AS : Aliases) {
4791     auto AliasValueId = SummaryToValueIdMap[AS];
4792     assert(AliasValueId);
4793     NameVals.push_back(AliasValueId);
4794     assert(ModuleIdMap.count(AS->modulePath()));
4795     NameVals.push_back(ModuleIdMap[AS->modulePath()]);
4796     NameVals.push_back(
4797         getEncodedGVSummaryFlags(AS->flags(), shouldImportValueAsDecl(AS)));
4798     auto AliaseeValueId = SummaryToValueIdMap[&AS->getAliasee()];
4799     assert(AliaseeValueId);
4800     NameVals.push_back(AliaseeValueId);
4801 
4802     // Emit the finished record.
4803     Stream.EmitRecord(bitc::FS_COMBINED_ALIAS, NameVals, FSAliasAbbrev);
4804     NameVals.clear();
4805     MaybeEmitOriginalName(*AS);
4806 
4807     if (auto *FS = dyn_cast<FunctionSummary>(&AS->getAliasee()))
4808       getReferencedTypeIds(FS, ReferencedTypeIds);
4809   }
4810 
4811   if (!Index.cfiFunctionDefs().empty()) {
4812     for (auto &S : Index.cfiFunctionDefs()) {
4813       if (DefOrUseGUIDs.contains(
4814               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4815         NameVals.push_back(StrtabBuilder.add(S));
4816         NameVals.push_back(S.size());
4817       }
4818     }
4819     if (!NameVals.empty()) {
4820       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DEFS, NameVals);
4821       NameVals.clear();
4822     }
4823   }
4824 
4825   if (!Index.cfiFunctionDecls().empty()) {
4826     for (auto &S : Index.cfiFunctionDecls()) {
4827       if (DefOrUseGUIDs.contains(
4828               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4829         NameVals.push_back(StrtabBuilder.add(S));
4830         NameVals.push_back(S.size());
4831       }
4832     }
4833     if (!NameVals.empty()) {
4834       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DECLS, NameVals);
4835       NameVals.clear();
4836     }
4837   }
4838 
4839   // Walk the GUIDs that were referenced, and write the
4840   // corresponding type id records.
4841   for (auto &T : ReferencedTypeIds) {
4842     auto TidIter = Index.typeIds().equal_range(T);
4843     for (const auto &[GUID, TypeIdPair] : make_range(TidIter)) {
4844       writeTypeIdSummaryRecord(NameVals, StrtabBuilder, TypeIdPair.first,
4845                                TypeIdPair.second);
4846       Stream.EmitRecord(bitc::FS_TYPE_ID, NameVals);
4847       NameVals.clear();
4848     }
4849   }
4850 
4851   if (Index.getBlockCount())
4852     Stream.EmitRecord(bitc::FS_BLOCK_COUNT,
4853                       ArrayRef<uint64_t>{Index.getBlockCount()});
4854 
4855   Stream.ExitBlock();
4856 }
4857 
4858 /// Create the "IDENTIFICATION_BLOCK_ID" containing a single string with the
4859 /// current llvm version, and a record for the epoch number.
4860 static void writeIdentificationBlock(BitstreamWriter &Stream) {
4861   Stream.EnterSubblock(bitc::IDENTIFICATION_BLOCK_ID, 5);
4862 
4863   // Write the "user readable" string identifying the bitcode producer
4864   auto Abbv = std::make_shared<BitCodeAbbrev>();
4865   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_STRING));
4866   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4867   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
4868   auto StringAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4869   writeStringRecord(Stream, bitc::IDENTIFICATION_CODE_STRING,
4870                     "LLVM" LLVM_VERSION_STRING, StringAbbrev);
4871 
4872   // Write the epoch version
4873   Abbv = std::make_shared<BitCodeAbbrev>();
4874   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_EPOCH));
4875   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
4876   auto EpochAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4877   constexpr std::array<unsigned, 1> Vals = {{bitc::BITCODE_CURRENT_EPOCH}};
4878   Stream.EmitRecord(bitc::IDENTIFICATION_CODE_EPOCH, Vals, EpochAbbrev);
4879   Stream.ExitBlock();
4880 }
4881 
4882 void ModuleBitcodeWriter::writeModuleHash(StringRef View) {
4883   // Emit the module's hash.
4884   // MODULE_CODE_HASH: [5*i32]
4885   if (GenerateHash) {
4886     uint32_t Vals[5];
4887     Hasher.update(ArrayRef<uint8_t>(
4888         reinterpret_cast<const uint8_t *>(View.data()), View.size()));
4889     std::array<uint8_t, 20> Hash = Hasher.result();
4890     for (int Pos = 0; Pos < 20; Pos += 4) {
4891       Vals[Pos / 4] = support::endian::read32be(Hash.data() + Pos);
4892     }
4893 
4894     // Emit the finished record.
4895     Stream.EmitRecord(bitc::MODULE_CODE_HASH, Vals);
4896 
4897     if (ModHash)
4898       // Save the written hash value.
4899       llvm::copy(Vals, std::begin(*ModHash));
4900   }
4901 }
4902 
4903 void ModuleBitcodeWriter::write() {
4904   writeIdentificationBlock(Stream);
4905 
4906   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4907   // We will want to write the module hash at this point. Block any flushing so
4908   // we can have access to the whole underlying data later.
4909   Stream.markAndBlockFlushing();
4910 
4911   writeModuleVersion();
4912 
4913   // Emit blockinfo, which defines the standard abbreviations etc.
4914   writeBlockInfo();
4915 
4916   // Emit information describing all of the types in the module.
4917   writeTypeTable();
4918 
4919   // Emit information about attribute groups.
4920   writeAttributeGroupTable();
4921 
4922   // Emit information about parameter attributes.
4923   writeAttributeTable();
4924 
4925   writeComdats();
4926 
4927   // Emit top-level description of module, including target triple, inline asm,
4928   // descriptors for global variables, and function prototype info.
4929   writeModuleInfo();
4930 
4931   // Emit constants.
4932   writeModuleConstants();
4933 
4934   // Emit metadata kind names.
4935   writeModuleMetadataKinds();
4936 
4937   // Emit metadata.
4938   writeModuleMetadata();
4939 
4940   // Emit module-level use-lists.
4941   if (VE.shouldPreserveUseListOrder())
4942     writeUseListBlock(nullptr);
4943 
4944   writeOperandBundleTags();
4945   writeSyncScopeNames();
4946 
4947   // Emit function bodies.
4948   DenseMap<const Function *, uint64_t> FunctionToBitcodeIndex;
4949   for (const Function &F : M)
4950     if (!F.isDeclaration())
4951       writeFunction(F, FunctionToBitcodeIndex);
4952 
4953   // Need to write after the above call to WriteFunction which populates
4954   // the summary information in the index.
4955   if (Index)
4956     writePerModuleGlobalValueSummary();
4957 
4958   writeGlobalValueSymbolTable(FunctionToBitcodeIndex);
4959 
4960   writeModuleHash(Stream.getMarkedBufferAndResumeFlushing());
4961 
4962   Stream.ExitBlock();
4963 }
4964 
4965 static void writeInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
4966                                uint32_t &Position) {
4967   support::endian::write32le(&Buffer[Position], Value);
4968   Position += 4;
4969 }
4970 
4971 /// If generating a bc file on darwin, we have to emit a
4972 /// header and trailer to make it compatible with the system archiver.  To do
4973 /// this we emit the following header, and then emit a trailer that pads the
4974 /// file out to be a multiple of 16 bytes.
4975 ///
4976 /// struct bc_header {
4977 ///   uint32_t Magic;         // 0x0B17C0DE
4978 ///   uint32_t Version;       // Version, currently always 0.
4979 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
4980 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
4981 ///   uint32_t CPUType;       // CPU specifier.
4982 ///   ... potentially more later ...
4983 /// };
4984 static void emitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
4985                                          const Triple &TT) {
4986   unsigned CPUType = ~0U;
4987 
4988   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
4989   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
4990   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
4991   // specific constants here because they are implicitly part of the Darwin ABI.
4992   enum {
4993     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
4994     DARWIN_CPU_TYPE_X86        = 7,
4995     DARWIN_CPU_TYPE_ARM        = 12,
4996     DARWIN_CPU_TYPE_POWERPC    = 18
4997   };
4998 
4999   Triple::ArchType Arch = TT.getArch();
5000   if (Arch == Triple::x86_64)
5001     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
5002   else if (Arch == Triple::x86)
5003     CPUType = DARWIN_CPU_TYPE_X86;
5004   else if (Arch == Triple::ppc)
5005     CPUType = DARWIN_CPU_TYPE_POWERPC;
5006   else if (Arch == Triple::ppc64)
5007     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
5008   else if (Arch == Triple::arm || Arch == Triple::thumb)
5009     CPUType = DARWIN_CPU_TYPE_ARM;
5010 
5011   // Traditional Bitcode starts after header.
5012   assert(Buffer.size() >= BWH_HeaderSize &&
5013          "Expected header size to be reserved");
5014   unsigned BCOffset = BWH_HeaderSize;
5015   unsigned BCSize = Buffer.size() - BWH_HeaderSize;
5016 
5017   // Write the magic and version.
5018   unsigned Position = 0;
5019   writeInt32ToBuffer(0x0B17C0DE, Buffer, Position);
5020   writeInt32ToBuffer(0, Buffer, Position); // Version.
5021   writeInt32ToBuffer(BCOffset, Buffer, Position);
5022   writeInt32ToBuffer(BCSize, Buffer, Position);
5023   writeInt32ToBuffer(CPUType, Buffer, Position);
5024 
5025   // If the file is not a multiple of 16 bytes, insert dummy padding.
5026   while (Buffer.size() & 15)
5027     Buffer.push_back(0);
5028 }
5029 
5030 /// Helper to write the header common to all bitcode files.
5031 static void writeBitcodeHeader(BitstreamWriter &Stream) {
5032   // Emit the file header.
5033   Stream.Emit((unsigned)'B', 8);
5034   Stream.Emit((unsigned)'C', 8);
5035   Stream.Emit(0x0, 4);
5036   Stream.Emit(0xC, 4);
5037   Stream.Emit(0xE, 4);
5038   Stream.Emit(0xD, 4);
5039 }
5040 
5041 BitcodeWriter::BitcodeWriter(SmallVectorImpl<char> &Buffer)
5042     : Stream(new BitstreamWriter(Buffer)) {
5043   writeBitcodeHeader(*Stream);
5044 }
5045 
5046 BitcodeWriter::BitcodeWriter(raw_ostream &FS)
5047     : Stream(new BitstreamWriter(FS, FlushThreshold)) {
5048   writeBitcodeHeader(*Stream);
5049 }
5050 
5051 BitcodeWriter::~BitcodeWriter() { assert(WroteStrtab); }
5052 
5053 void BitcodeWriter::writeBlob(unsigned Block, unsigned Record, StringRef Blob) {
5054   Stream->EnterSubblock(Block, 3);
5055 
5056   auto Abbv = std::make_shared<BitCodeAbbrev>();
5057   Abbv->Add(BitCodeAbbrevOp(Record));
5058   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
5059   auto AbbrevNo = Stream->EmitAbbrev(std::move(Abbv));
5060 
5061   Stream->EmitRecordWithBlob(AbbrevNo, ArrayRef<uint64_t>{Record}, Blob);
5062 
5063   Stream->ExitBlock();
5064 }
5065 
5066 void BitcodeWriter::writeSymtab() {
5067   assert(!WroteStrtab && !WroteSymtab);
5068 
5069   // If any module has module-level inline asm, we will require a registered asm
5070   // parser for the target so that we can create an accurate symbol table for
5071   // the module.
5072   for (Module *M : Mods) {
5073     if (M->getModuleInlineAsm().empty())
5074       continue;
5075 
5076     std::string Err;
5077     const Triple TT(M->getTargetTriple());
5078     const Target *T = TargetRegistry::lookupTarget(TT.str(), Err);
5079     if (!T || !T->hasMCAsmParser())
5080       return;
5081   }
5082 
5083   WroteSymtab = true;
5084   SmallVector<char, 0> Symtab;
5085   // The irsymtab::build function may be unable to create a symbol table if the
5086   // module is malformed (e.g. it contains an invalid alias). Writing a symbol
5087   // table is not required for correctness, but we still want to be able to
5088   // write malformed modules to bitcode files, so swallow the error.
5089   if (Error E = irsymtab::build(Mods, Symtab, StrtabBuilder, Alloc)) {
5090     consumeError(std::move(E));
5091     return;
5092   }
5093 
5094   writeBlob(bitc::SYMTAB_BLOCK_ID, bitc::SYMTAB_BLOB,
5095             {Symtab.data(), Symtab.size()});
5096 }
5097 
5098 void BitcodeWriter::writeStrtab() {
5099   assert(!WroteStrtab);
5100 
5101   std::vector<char> Strtab;
5102   StrtabBuilder.finalizeInOrder();
5103   Strtab.resize(StrtabBuilder.getSize());
5104   StrtabBuilder.write((uint8_t *)Strtab.data());
5105 
5106   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB,
5107             {Strtab.data(), Strtab.size()});
5108 
5109   WroteStrtab = true;
5110 }
5111 
5112 void BitcodeWriter::copyStrtab(StringRef Strtab) {
5113   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB, Strtab);
5114   WroteStrtab = true;
5115 }
5116 
5117 void BitcodeWriter::writeModule(const Module &M,
5118                                 bool ShouldPreserveUseListOrder,
5119                                 const ModuleSummaryIndex *Index,
5120                                 bool GenerateHash, ModuleHash *ModHash) {
5121   assert(!WroteStrtab);
5122 
5123   // The Mods vector is used by irsymtab::build, which requires non-const
5124   // Modules in case it needs to materialize metadata. But the bitcode writer
5125   // requires that the module is materialized, so we can cast to non-const here,
5126   // after checking that it is in fact materialized.
5127   assert(M.isMaterialized());
5128   Mods.push_back(const_cast<Module *>(&M));
5129 
5130   ModuleBitcodeWriter ModuleWriter(M, StrtabBuilder, *Stream,
5131                                    ShouldPreserveUseListOrder, Index,
5132                                    GenerateHash, ModHash);
5133   ModuleWriter.write();
5134 }
5135 
5136 void BitcodeWriter::writeIndex(
5137     const ModuleSummaryIndex *Index,
5138     const ModuleToSummariesForIndexTy *ModuleToSummariesForIndex,
5139     const GVSummaryPtrSet *DecSummaries) {
5140   IndexBitcodeWriter IndexWriter(*Stream, StrtabBuilder, *Index, DecSummaries,
5141                                  ModuleToSummariesForIndex);
5142   IndexWriter.write();
5143 }
5144 
5145 /// Write the specified module to the specified output stream.
5146 void llvm::WriteBitcodeToFile(const Module &M, raw_ostream &Out,
5147                               bool ShouldPreserveUseListOrder,
5148                               const ModuleSummaryIndex *Index,
5149                               bool GenerateHash, ModuleHash *ModHash) {
5150   auto Write = [&](BitcodeWriter &Writer) {
5151     Writer.writeModule(M, ShouldPreserveUseListOrder, Index, GenerateHash,
5152                        ModHash);
5153     Writer.writeSymtab();
5154     Writer.writeStrtab();
5155   };
5156   Triple TT(M.getTargetTriple());
5157   if (TT.isOSDarwin() || TT.isOSBinFormatMachO()) {
5158     // If this is darwin or another generic macho target, reserve space for the
5159     // header. Note that the header is computed *after* the output is known, so
5160     // we currently explicitly use a buffer, write to it, and then subsequently
5161     // flush to Out.
5162     SmallVector<char, 0> Buffer;
5163     Buffer.reserve(256 * 1024);
5164     Buffer.insert(Buffer.begin(), BWH_HeaderSize, 0);
5165     BitcodeWriter Writer(Buffer);
5166     Write(Writer);
5167     emitDarwinBCHeaderAndTrailer(Buffer, TT);
5168     Out.write(Buffer.data(), Buffer.size());
5169   } else {
5170     BitcodeWriter Writer(Out);
5171     Write(Writer);
5172   }
5173 }
5174 
5175 void IndexBitcodeWriter::write() {
5176   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
5177 
5178   writeModuleVersion();
5179 
5180   // Write the module paths in the combined index.
5181   writeModStrings();
5182 
5183   // Write the summary combined index records.
5184   writeCombinedGlobalValueSummary();
5185 
5186   Stream.ExitBlock();
5187 }
5188 
5189 // Write the specified module summary index to the given raw output stream,
5190 // where it will be written in a new bitcode block. This is used when
5191 // writing the combined index file for ThinLTO. When writing a subset of the
5192 // index for a distributed backend, provide a \p ModuleToSummariesForIndex map.
5193 void llvm::writeIndexToFile(
5194     const ModuleSummaryIndex &Index, raw_ostream &Out,
5195     const ModuleToSummariesForIndexTy *ModuleToSummariesForIndex,
5196     const GVSummaryPtrSet *DecSummaries) {
5197   SmallVector<char, 0> Buffer;
5198   Buffer.reserve(256 * 1024);
5199 
5200   BitcodeWriter Writer(Buffer);
5201   Writer.writeIndex(&Index, ModuleToSummariesForIndex, DecSummaries);
5202   Writer.writeStrtab();
5203 
5204   Out.write((char *)&Buffer.front(), Buffer.size());
5205 }
5206 
5207 namespace {
5208 
5209 /// Class to manage the bitcode writing for a thin link bitcode file.
5210 class ThinLinkBitcodeWriter : public ModuleBitcodeWriterBase {
5211   /// ModHash is for use in ThinLTO incremental build, generated while writing
5212   /// the module bitcode file.
5213   const ModuleHash *ModHash;
5214 
5215 public:
5216   ThinLinkBitcodeWriter(const Module &M, StringTableBuilder &StrtabBuilder,
5217                         BitstreamWriter &Stream,
5218                         const ModuleSummaryIndex &Index,
5219                         const ModuleHash &ModHash)
5220       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
5221                                 /*ShouldPreserveUseListOrder=*/false, &Index),
5222         ModHash(&ModHash) {}
5223 
5224   void write();
5225 
5226 private:
5227   void writeSimplifiedModuleInfo();
5228 };
5229 
5230 } // end anonymous namespace
5231 
5232 // This function writes a simpilified module info for thin link bitcode file.
5233 // It only contains the source file name along with the name(the offset and
5234 // size in strtab) and linkage for global values. For the global value info
5235 // entry, in order to keep linkage at offset 5, there are three zeros used
5236 // as padding.
5237 void ThinLinkBitcodeWriter::writeSimplifiedModuleInfo() {
5238   SmallVector<unsigned, 64> Vals;
5239   // Emit the module's source file name.
5240   {
5241     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
5242     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
5243     if (Bits == SE_Char6)
5244       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
5245     else if (Bits == SE_Fixed7)
5246       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
5247 
5248     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
5249     auto Abbv = std::make_shared<BitCodeAbbrev>();
5250     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
5251     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
5252     Abbv->Add(AbbrevOpToUse);
5253     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
5254 
5255     for (const auto P : M.getSourceFileName())
5256       Vals.push_back((unsigned char)P);
5257 
5258     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
5259     Vals.clear();
5260   }
5261 
5262   // Emit the global variable information.
5263   for (const GlobalVariable &GV : M.globals()) {
5264     // GLOBALVAR: [strtab offset, strtab size, 0, 0, 0, linkage]
5265     Vals.push_back(StrtabBuilder.add(GV.getName()));
5266     Vals.push_back(GV.getName().size());
5267     Vals.push_back(0);
5268     Vals.push_back(0);
5269     Vals.push_back(0);
5270     Vals.push_back(getEncodedLinkage(GV));
5271 
5272     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals);
5273     Vals.clear();
5274   }
5275 
5276   // Emit the function proto information.
5277   for (const Function &F : M) {
5278     // FUNCTION:  [strtab offset, strtab size, 0, 0, 0, linkage]
5279     Vals.push_back(StrtabBuilder.add(F.getName()));
5280     Vals.push_back(F.getName().size());
5281     Vals.push_back(0);
5282     Vals.push_back(0);
5283     Vals.push_back(0);
5284     Vals.push_back(getEncodedLinkage(F));
5285 
5286     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals);
5287     Vals.clear();
5288   }
5289 
5290   // Emit the alias information.
5291   for (const GlobalAlias &A : M.aliases()) {
5292     // ALIAS: [strtab offset, strtab size, 0, 0, 0, linkage]
5293     Vals.push_back(StrtabBuilder.add(A.getName()));
5294     Vals.push_back(A.getName().size());
5295     Vals.push_back(0);
5296     Vals.push_back(0);
5297     Vals.push_back(0);
5298     Vals.push_back(getEncodedLinkage(A));
5299 
5300     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals);
5301     Vals.clear();
5302   }
5303 
5304   // Emit the ifunc information.
5305   for (const GlobalIFunc &I : M.ifuncs()) {
5306     // IFUNC: [strtab offset, strtab size, 0, 0, 0, linkage]
5307     Vals.push_back(StrtabBuilder.add(I.getName()));
5308     Vals.push_back(I.getName().size());
5309     Vals.push_back(0);
5310     Vals.push_back(0);
5311     Vals.push_back(0);
5312     Vals.push_back(getEncodedLinkage(I));
5313 
5314     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
5315     Vals.clear();
5316   }
5317 }
5318 
5319 void ThinLinkBitcodeWriter::write() {
5320   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
5321 
5322   writeModuleVersion();
5323 
5324   writeSimplifiedModuleInfo();
5325 
5326   writePerModuleGlobalValueSummary();
5327 
5328   // Write module hash.
5329   Stream.EmitRecord(bitc::MODULE_CODE_HASH, ArrayRef<uint32_t>(*ModHash));
5330 
5331   Stream.ExitBlock();
5332 }
5333 
5334 void BitcodeWriter::writeThinLinkBitcode(const Module &M,
5335                                          const ModuleSummaryIndex &Index,
5336                                          const ModuleHash &ModHash) {
5337   assert(!WroteStrtab);
5338 
5339   // The Mods vector is used by irsymtab::build, which requires non-const
5340   // Modules in case it needs to materialize metadata. But the bitcode writer
5341   // requires that the module is materialized, so we can cast to non-const here,
5342   // after checking that it is in fact materialized.
5343   assert(M.isMaterialized());
5344   Mods.push_back(const_cast<Module *>(&M));
5345 
5346   ThinLinkBitcodeWriter ThinLinkWriter(M, StrtabBuilder, *Stream, Index,
5347                                        ModHash);
5348   ThinLinkWriter.write();
5349 }
5350 
5351 // Write the specified thin link bitcode file to the given raw output stream,
5352 // where it will be written in a new bitcode block. This is used when
5353 // writing the per-module index file for ThinLTO.
5354 void llvm::writeThinLinkBitcodeToFile(const Module &M, raw_ostream &Out,
5355                                       const ModuleSummaryIndex &Index,
5356                                       const ModuleHash &ModHash) {
5357   SmallVector<char, 0> Buffer;
5358   Buffer.reserve(256 * 1024);
5359 
5360   BitcodeWriter Writer(Buffer);
5361   Writer.writeThinLinkBitcode(M, Index, ModHash);
5362   Writer.writeSymtab();
5363   Writer.writeStrtab();
5364 
5365   Out.write((char *)&Buffer.front(), Buffer.size());
5366 }
5367 
5368 static const char *getSectionNameForBitcode(const Triple &T) {
5369   switch (T.getObjectFormat()) {
5370   case Triple::MachO:
5371     return "__LLVM,__bitcode";
5372   case Triple::COFF:
5373   case Triple::ELF:
5374   case Triple::Wasm:
5375   case Triple::UnknownObjectFormat:
5376     return ".llvmbc";
5377   case Triple::GOFF:
5378     llvm_unreachable("GOFF is not yet implemented");
5379     break;
5380   case Triple::SPIRV:
5381     if (T.getVendor() == Triple::AMD)
5382       return ".llvmbc";
5383     llvm_unreachable("SPIRV is not yet implemented");
5384     break;
5385   case Triple::XCOFF:
5386     llvm_unreachable("XCOFF is not yet implemented");
5387     break;
5388   case Triple::DXContainer:
5389     llvm_unreachable("DXContainer is not yet implemented");
5390     break;
5391   }
5392   llvm_unreachable("Unimplemented ObjectFormatType");
5393 }
5394 
5395 static const char *getSectionNameForCommandline(const Triple &T) {
5396   switch (T.getObjectFormat()) {
5397   case Triple::MachO:
5398     return "__LLVM,__cmdline";
5399   case Triple::COFF:
5400   case Triple::ELF:
5401   case Triple::Wasm:
5402   case Triple::UnknownObjectFormat:
5403     return ".llvmcmd";
5404   case Triple::GOFF:
5405     llvm_unreachable("GOFF is not yet implemented");
5406     break;
5407   case Triple::SPIRV:
5408     if (T.getVendor() == Triple::AMD)
5409       return ".llvmcmd";
5410     llvm_unreachable("SPIRV is not yet implemented");
5411     break;
5412   case Triple::XCOFF:
5413     llvm_unreachable("XCOFF is not yet implemented");
5414     break;
5415   case Triple::DXContainer:
5416     llvm_unreachable("DXC is not yet implemented");
5417     break;
5418   }
5419   llvm_unreachable("Unimplemented ObjectFormatType");
5420 }
5421 
5422 void llvm::embedBitcodeInModule(llvm::Module &M, llvm::MemoryBufferRef Buf,
5423                                 bool EmbedBitcode, bool EmbedCmdline,
5424                                 const std::vector<uint8_t> &CmdArgs) {
5425   // Save llvm.compiler.used and remove it.
5426   SmallVector<Constant *, 2> UsedArray;
5427   SmallVector<GlobalValue *, 4> UsedGlobals;
5428   Type *UsedElementType = PointerType::getUnqual(M.getContext());
5429   GlobalVariable *Used = collectUsedGlobalVariables(M, UsedGlobals, true);
5430   for (auto *GV : UsedGlobals) {
5431     if (GV->getName() != "llvm.embedded.module" &&
5432         GV->getName() != "llvm.cmdline")
5433       UsedArray.push_back(
5434           ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
5435   }
5436   if (Used)
5437     Used->eraseFromParent();
5438 
5439   // Embed the bitcode for the llvm module.
5440   std::string Data;
5441   ArrayRef<uint8_t> ModuleData;
5442   Triple T(M.getTargetTriple());
5443 
5444   if (EmbedBitcode) {
5445     if (Buf.getBufferSize() == 0 ||
5446         !isBitcode((const unsigned char *)Buf.getBufferStart(),
5447                    (const unsigned char *)Buf.getBufferEnd())) {
5448       // If the input is LLVM Assembly, bitcode is produced by serializing
5449       // the module. Use-lists order need to be preserved in this case.
5450       llvm::raw_string_ostream OS(Data);
5451       llvm::WriteBitcodeToFile(M, OS, /* ShouldPreserveUseListOrder */ true);
5452       ModuleData =
5453           ArrayRef<uint8_t>((const uint8_t *)OS.str().data(), OS.str().size());
5454     } else
5455       // If the input is LLVM bitcode, write the input byte stream directly.
5456       ModuleData = ArrayRef<uint8_t>((const uint8_t *)Buf.getBufferStart(),
5457                                      Buf.getBufferSize());
5458   }
5459   llvm::Constant *ModuleConstant =
5460       llvm::ConstantDataArray::get(M.getContext(), ModuleData);
5461   llvm::GlobalVariable *GV = new llvm::GlobalVariable(
5462       M, ModuleConstant->getType(), true, llvm::GlobalValue::PrivateLinkage,
5463       ModuleConstant);
5464   GV->setSection(getSectionNameForBitcode(T));
5465   // Set alignment to 1 to prevent padding between two contributions from input
5466   // sections after linking.
5467   GV->setAlignment(Align(1));
5468   UsedArray.push_back(
5469       ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
5470   if (llvm::GlobalVariable *Old =
5471           M.getGlobalVariable("llvm.embedded.module", true)) {
5472     assert(Old->hasZeroLiveUses() &&
5473            "llvm.embedded.module can only be used once in llvm.compiler.used");
5474     GV->takeName(Old);
5475     Old->eraseFromParent();
5476   } else {
5477     GV->setName("llvm.embedded.module");
5478   }
5479 
5480   // Skip if only bitcode needs to be embedded.
5481   if (EmbedCmdline) {
5482     // Embed command-line options.
5483     ArrayRef<uint8_t> CmdData(const_cast<uint8_t *>(CmdArgs.data()),
5484                               CmdArgs.size());
5485     llvm::Constant *CmdConstant =
5486         llvm::ConstantDataArray::get(M.getContext(), CmdData);
5487     GV = new llvm::GlobalVariable(M, CmdConstant->getType(), true,
5488                                   llvm::GlobalValue::PrivateLinkage,
5489                                   CmdConstant);
5490     GV->setSection(getSectionNameForCommandline(T));
5491     GV->setAlignment(Align(1));
5492     UsedArray.push_back(
5493         ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
5494     if (llvm::GlobalVariable *Old = M.getGlobalVariable("llvm.cmdline", true)) {
5495       assert(Old->hasZeroLiveUses() &&
5496              "llvm.cmdline can only be used once in llvm.compiler.used");
5497       GV->takeName(Old);
5498       Old->eraseFromParent();
5499     } else {
5500       GV->setName("llvm.cmdline");
5501     }
5502   }
5503 
5504   if (UsedArray.empty())
5505     return;
5506 
5507   // Recreate llvm.compiler.used.
5508   ArrayType *ATy = ArrayType::get(UsedElementType, UsedArray.size());
5509   auto *NewUsed = new GlobalVariable(
5510       M, ATy, false, llvm::GlobalValue::AppendingLinkage,
5511       llvm::ConstantArray::get(ATy, UsedArray), "llvm.compiler.used");
5512   NewUsed->setSection("llvm.metadata");
5513 }
5514