xref: /llvm-project/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp (revision 304f1d59ca41872c094def3aee0a8689df6aa398)
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/None.h"
20 #include "llvm/ADT/Optional.h"
21 #include "llvm/ADT/STLExtras.h"
22 #include "llvm/ADT/SetVector.h"
23 #include "llvm/ADT/SmallPtrSet.h"
24 #include "llvm/ADT/SmallString.h"
25 #include "llvm/ADT/SmallVector.h"
26 #include "llvm/ADT/StringMap.h"
27 #include "llvm/ADT/StringRef.h"
28 #include "llvm/ADT/Triple.h"
29 #include "llvm/Bitcode/BitcodeCommon.h"
30 #include "llvm/Bitcode/BitcodeReader.h"
31 #include "llvm/Bitcode/LLVMBitCodes.h"
32 #include "llvm/Bitstream/BitCodes.h"
33 #include "llvm/Bitstream/BitstreamWriter.h"
34 #include "llvm/Config/llvm-config.h"
35 #include "llvm/IR/Attributes.h"
36 #include "llvm/IR/BasicBlock.h"
37 #include "llvm/IR/Comdat.h"
38 #include "llvm/IR/Constant.h"
39 #include "llvm/IR/Constants.h"
40 #include "llvm/IR/DebugInfoMetadata.h"
41 #include "llvm/IR/DebugLoc.h"
42 #include "llvm/IR/DerivedTypes.h"
43 #include "llvm/IR/Function.h"
44 #include "llvm/IR/GlobalAlias.h"
45 #include "llvm/IR/GlobalIFunc.h"
46 #include "llvm/IR/GlobalObject.h"
47 #include "llvm/IR/GlobalValue.h"
48 #include "llvm/IR/GlobalVariable.h"
49 #include "llvm/IR/InlineAsm.h"
50 #include "llvm/IR/InstrTypes.h"
51 #include "llvm/IR/Instruction.h"
52 #include "llvm/IR/Instructions.h"
53 #include "llvm/IR/LLVMContext.h"
54 #include "llvm/IR/Metadata.h"
55 #include "llvm/IR/Module.h"
56 #include "llvm/IR/ModuleSummaryIndex.h"
57 #include "llvm/IR/Operator.h"
58 #include "llvm/IR/Type.h"
59 #include "llvm/IR/UseListOrder.h"
60 #include "llvm/IR/Value.h"
61 #include "llvm/IR/ValueSymbolTable.h"
62 #include "llvm/MC/StringTableBuilder.h"
63 #include "llvm/MC/TargetRegistry.h"
64 #include "llvm/Object/IRSymtab.h"
65 #include "llvm/Support/AtomicOrdering.h"
66 #include "llvm/Support/Casting.h"
67 #include "llvm/Support/CommandLine.h"
68 #include "llvm/Support/Endian.h"
69 #include "llvm/Support/Error.h"
70 #include "llvm/Support/ErrorHandling.h"
71 #include "llvm/Support/MathExtras.h"
72 #include "llvm/Support/SHA1.h"
73 #include "llvm/Support/raw_ostream.h"
74 #include <algorithm>
75 #include <cassert>
76 #include <cstddef>
77 #include <cstdint>
78 #include <iterator>
79 #include <map>
80 #include <memory>
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 extern FunctionSummary::ForceSummaryHotnessType ForceSummaryEdgesCold;
100 
101 namespace {
102 
103 /// These are manifest constants used by the bitcode writer. They do not need to
104 /// be kept in sync with the reader, but need to be consistent within this file.
105 enum {
106   // VALUE_SYMTAB_BLOCK abbrev id's.
107   VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
108   VST_ENTRY_7_ABBREV,
109   VST_ENTRY_6_ABBREV,
110   VST_BBENTRY_6_ABBREV,
111 
112   // CONSTANTS_BLOCK abbrev id's.
113   CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
114   CONSTANTS_INTEGER_ABBREV,
115   CONSTANTS_CE_CAST_Abbrev,
116   CONSTANTS_NULL_Abbrev,
117 
118   // FUNCTION_BLOCK abbrev id's.
119   FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
120   FUNCTION_INST_UNOP_ABBREV,
121   FUNCTION_INST_UNOP_FLAGS_ABBREV,
122   FUNCTION_INST_BINOP_ABBREV,
123   FUNCTION_INST_BINOP_FLAGS_ABBREV,
124   FUNCTION_INST_CAST_ABBREV,
125   FUNCTION_INST_RET_VOID_ABBREV,
126   FUNCTION_INST_RET_VAL_ABBREV,
127   FUNCTION_INST_UNREACHABLE_ABBREV,
128   FUNCTION_INST_GEP_ABBREV,
129 };
130 
131 /// Abstract class to manage the bitcode writing, subclassed for each bitcode
132 /// file type.
133 class BitcodeWriterBase {
134 protected:
135   /// The stream created and owned by the client.
136   BitstreamWriter &Stream;
137 
138   StringTableBuilder &StrtabBuilder;
139 
140 public:
141   /// Constructs a BitcodeWriterBase object that writes to the provided
142   /// \p Stream.
143   BitcodeWriterBase(BitstreamWriter &Stream, StringTableBuilder &StrtabBuilder)
144       : Stream(Stream), StrtabBuilder(StrtabBuilder) {}
145 
146 protected:
147   void writeModuleVersion();
148 };
149 
150 void BitcodeWriterBase::writeModuleVersion() {
151   // VERSION: [version#]
152   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, ArrayRef<uint64_t>{2});
153 }
154 
155 /// Base class to manage the module bitcode writing, currently subclassed for
156 /// ModuleBitcodeWriter and ThinLinkBitcodeWriter.
157 class ModuleBitcodeWriterBase : public BitcodeWriterBase {
158 protected:
159   /// The Module to write to bitcode.
160   const Module &M;
161 
162   /// Enumerates ids for all values in the module.
163   ValueEnumerator VE;
164 
165   /// Optional per-module index to write for ThinLTO.
166   const ModuleSummaryIndex *Index;
167 
168   /// Map that holds the correspondence between GUIDs in the summary index,
169   /// that came from indirect call profiles, and a value id generated by this
170   /// class to use in the VST and summary block records.
171   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
172 
173   /// Tracks the last value id recorded in the GUIDToValueMap.
174   unsigned GlobalValueId;
175 
176   /// Saves the offset of the VSTOffset record that must eventually be
177   /// backpatched with the offset of the actual VST.
178   uint64_t VSTOffsetPlaceholder = 0;
179 
180 public:
181   /// Constructs a ModuleBitcodeWriterBase object for the given Module,
182   /// writing to the provided \p Buffer.
183   ModuleBitcodeWriterBase(const Module &M, StringTableBuilder &StrtabBuilder,
184                           BitstreamWriter &Stream,
185                           bool ShouldPreserveUseListOrder,
186                           const ModuleSummaryIndex *Index)
187       : BitcodeWriterBase(Stream, StrtabBuilder), M(M),
188         VE(M, ShouldPreserveUseListOrder), Index(Index) {
189     // Assign ValueIds to any callee values in the index that came from
190     // indirect call profiles and were recorded as a GUID not a Value*
191     // (which would have been assigned an ID by the ValueEnumerator).
192     // The starting ValueId is just after the number of values in the
193     // ValueEnumerator, so that they can be emitted in the VST.
194     GlobalValueId = VE.getValues().size();
195     if (!Index)
196       return;
197     for (const auto &GUIDSummaryLists : *Index)
198       // Examine all summaries for this GUID.
199       for (auto &Summary : GUIDSummaryLists.second.SummaryList)
200         if (auto FS = dyn_cast<FunctionSummary>(Summary.get()))
201           // For each call in the function summary, see if the call
202           // is to a GUID (which means it is for an indirect call,
203           // otherwise we would have a Value for it). If so, synthesize
204           // a value id.
205           for (auto &CallEdge : FS->calls())
206             if (!CallEdge.first.haveGVs() || !CallEdge.first.getValue())
207               assignValueId(CallEdge.first.getGUID());
208   }
209 
210 protected:
211   void writePerModuleGlobalValueSummary();
212 
213 private:
214   void writePerModuleFunctionSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
215                                            GlobalValueSummary *Summary,
216                                            unsigned ValueID,
217                                            unsigned FSCallsAbbrev,
218                                            unsigned FSCallsProfileAbbrev,
219                                            const Function &F);
220   void writeModuleLevelReferences(const GlobalVariable &V,
221                                   SmallVector<uint64_t, 64> &NameVals,
222                                   unsigned FSModRefsAbbrev,
223                                   unsigned FSModVTableRefsAbbrev);
224 
225   void assignValueId(GlobalValue::GUID ValGUID) {
226     GUIDToValueIdMap[ValGUID] = ++GlobalValueId;
227   }
228 
229   unsigned getValueId(GlobalValue::GUID ValGUID) {
230     const auto &VMI = GUIDToValueIdMap.find(ValGUID);
231     // Expect that any GUID value had a value Id assigned by an
232     // earlier call to assignValueId.
233     assert(VMI != GUIDToValueIdMap.end() &&
234            "GUID does not have assigned value Id");
235     return VMI->second;
236   }
237 
238   // Helper to get the valueId for the type of value recorded in VI.
239   unsigned getValueId(ValueInfo VI) {
240     if (!VI.haveGVs() || !VI.getValue())
241       return getValueId(VI.getGUID());
242     return VE.getValueID(VI.getValue());
243   }
244 
245   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
246 };
247 
248 /// Class to manage the bitcode writing for a module.
249 class ModuleBitcodeWriter : public ModuleBitcodeWriterBase {
250   /// Pointer to the buffer allocated by caller for bitcode writing.
251   const SmallVectorImpl<char> &Buffer;
252 
253   /// True if a module hash record should be written.
254   bool GenerateHash;
255 
256   /// If non-null, when GenerateHash is true, the resulting hash is written
257   /// into ModHash.
258   ModuleHash *ModHash;
259 
260   SHA1 Hasher;
261 
262   /// The start bit of the identification block.
263   uint64_t BitcodeStartBit;
264 
265 public:
266   /// Constructs a ModuleBitcodeWriter object for the given Module,
267   /// writing to the provided \p Buffer.
268   ModuleBitcodeWriter(const Module &M, SmallVectorImpl<char> &Buffer,
269                       StringTableBuilder &StrtabBuilder,
270                       BitstreamWriter &Stream, bool ShouldPreserveUseListOrder,
271                       const ModuleSummaryIndex *Index, bool GenerateHash,
272                       ModuleHash *ModHash = nullptr)
273       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
274                                 ShouldPreserveUseListOrder, Index),
275         Buffer(Buffer), GenerateHash(GenerateHash), ModHash(ModHash),
276         BitcodeStartBit(Stream.GetCurrentBitNo()) {}
277 
278   /// Emit the current module to the bitstream.
279   void write();
280 
281 private:
282   uint64_t bitcodeStartBit() { return BitcodeStartBit; }
283 
284   size_t addToStrtab(StringRef Str);
285 
286   void writeAttributeGroupTable();
287   void writeAttributeTable();
288   void writeTypeTable();
289   void writeComdats();
290   void writeValueSymbolTableForwardDecl();
291   void writeModuleInfo();
292   void writeValueAsMetadata(const ValueAsMetadata *MD,
293                             SmallVectorImpl<uint64_t> &Record);
294   void writeMDTuple(const MDTuple *N, SmallVectorImpl<uint64_t> &Record,
295                     unsigned Abbrev);
296   unsigned createDILocationAbbrev();
297   void writeDILocation(const DILocation *N, SmallVectorImpl<uint64_t> &Record,
298                        unsigned &Abbrev);
299   unsigned createGenericDINodeAbbrev();
300   void writeGenericDINode(const GenericDINode *N,
301                           SmallVectorImpl<uint64_t> &Record, unsigned &Abbrev);
302   void writeDISubrange(const DISubrange *N, SmallVectorImpl<uint64_t> &Record,
303                        unsigned Abbrev);
304   void writeDIGenericSubrange(const DIGenericSubrange *N,
305                               SmallVectorImpl<uint64_t> &Record,
306                               unsigned Abbrev);
307   void writeDIEnumerator(const DIEnumerator *N,
308                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
309   void writeDIBasicType(const DIBasicType *N, SmallVectorImpl<uint64_t> &Record,
310                         unsigned Abbrev);
311   void writeDIStringType(const DIStringType *N,
312                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
313   void writeDIDerivedType(const DIDerivedType *N,
314                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
315   void writeDICompositeType(const DICompositeType *N,
316                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
317   void writeDISubroutineType(const DISubroutineType *N,
318                              SmallVectorImpl<uint64_t> &Record,
319                              unsigned Abbrev);
320   void writeDIFile(const DIFile *N, SmallVectorImpl<uint64_t> &Record,
321                    unsigned Abbrev);
322   void writeDICompileUnit(const DICompileUnit *N,
323                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
324   void writeDISubprogram(const DISubprogram *N,
325                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
326   void writeDILexicalBlock(const DILexicalBlock *N,
327                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
328   void writeDILexicalBlockFile(const DILexicalBlockFile *N,
329                                SmallVectorImpl<uint64_t> &Record,
330                                unsigned Abbrev);
331   void writeDICommonBlock(const DICommonBlock *N,
332                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
333   void writeDINamespace(const DINamespace *N, SmallVectorImpl<uint64_t> &Record,
334                         unsigned Abbrev);
335   void writeDIMacro(const DIMacro *N, SmallVectorImpl<uint64_t> &Record,
336                     unsigned Abbrev);
337   void writeDIMacroFile(const DIMacroFile *N, SmallVectorImpl<uint64_t> &Record,
338                         unsigned Abbrev);
339   void writeDIArgList(const DIArgList *N, SmallVectorImpl<uint64_t> &Record,
340                       unsigned Abbrev);
341   void writeDIModule(const DIModule *N, SmallVectorImpl<uint64_t> &Record,
342                      unsigned Abbrev);
343   void writeDITemplateTypeParameter(const DITemplateTypeParameter *N,
344                                     SmallVectorImpl<uint64_t> &Record,
345                                     unsigned Abbrev);
346   void writeDITemplateValueParameter(const DITemplateValueParameter *N,
347                                      SmallVectorImpl<uint64_t> &Record,
348                                      unsigned Abbrev);
349   void writeDIGlobalVariable(const DIGlobalVariable *N,
350                              SmallVectorImpl<uint64_t> &Record,
351                              unsigned Abbrev);
352   void writeDILocalVariable(const DILocalVariable *N,
353                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
354   void writeDILabel(const DILabel *N,
355                     SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
356   void writeDIExpression(const DIExpression *N,
357                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
358   void writeDIGlobalVariableExpression(const DIGlobalVariableExpression *N,
359                                        SmallVectorImpl<uint64_t> &Record,
360                                        unsigned Abbrev);
361   void writeDIObjCProperty(const DIObjCProperty *N,
362                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
363   void writeDIImportedEntity(const DIImportedEntity *N,
364                              SmallVectorImpl<uint64_t> &Record,
365                              unsigned Abbrev);
366   unsigned createNamedMetadataAbbrev();
367   void writeNamedMetadata(SmallVectorImpl<uint64_t> &Record);
368   unsigned createMetadataStringsAbbrev();
369   void writeMetadataStrings(ArrayRef<const Metadata *> Strings,
370                             SmallVectorImpl<uint64_t> &Record);
371   void writeMetadataRecords(ArrayRef<const Metadata *> MDs,
372                             SmallVectorImpl<uint64_t> &Record,
373                             std::vector<unsigned> *MDAbbrevs = nullptr,
374                             std::vector<uint64_t> *IndexPos = nullptr);
375   void writeModuleMetadata();
376   void writeFunctionMetadata(const Function &F);
377   void writeFunctionMetadataAttachment(const Function &F);
378   void pushGlobalMetadataAttachment(SmallVectorImpl<uint64_t> &Record,
379                                     const GlobalObject &GO);
380   void writeModuleMetadataKinds();
381   void writeOperandBundleTags();
382   void writeSyncScopeNames();
383   void writeConstants(unsigned FirstVal, unsigned LastVal, bool isGlobal);
384   void writeModuleConstants();
385   bool pushValueAndType(const Value *V, unsigned InstID,
386                         SmallVectorImpl<unsigned> &Vals);
387   void writeOperandBundles(const CallBase &CB, unsigned InstID);
388   void pushValue(const Value *V, unsigned InstID,
389                  SmallVectorImpl<unsigned> &Vals);
390   void pushValueSigned(const Value *V, unsigned InstID,
391                        SmallVectorImpl<uint64_t> &Vals);
392   void writeInstruction(const Instruction &I, unsigned InstID,
393                         SmallVectorImpl<unsigned> &Vals);
394   void writeFunctionLevelValueSymbolTable(const ValueSymbolTable &VST);
395   void writeGlobalValueSymbolTable(
396       DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
397   void writeUseList(UseListOrder &&Order);
398   void writeUseListBlock(const Function *F);
399   void
400   writeFunction(const Function &F,
401                 DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
402   void writeBlockInfo();
403   void writeModuleHash(size_t BlockStartPos);
404 
405   unsigned getEncodedSyncScopeID(SyncScope::ID SSID) {
406     return unsigned(SSID);
407   }
408 
409   unsigned getEncodedAlign(MaybeAlign Alignment) { return encode(Alignment); }
410 };
411 
412 /// Class to manage the bitcode writing for a combined index.
413 class IndexBitcodeWriter : public BitcodeWriterBase {
414   /// The combined index to write to bitcode.
415   const ModuleSummaryIndex &Index;
416 
417   /// When writing a subset of the index for distributed backends, client
418   /// provides a map of modules to the corresponding GUIDs/summaries to write.
419   const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex;
420 
421   /// Map that holds the correspondence between the GUID used in the combined
422   /// index and a value id generated by this class to use in references.
423   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
424 
425   /// Tracks the last value id recorded in the GUIDToValueMap.
426   unsigned GlobalValueId = 0;
427 
428 public:
429   /// Constructs a IndexBitcodeWriter object for the given combined index,
430   /// writing to the provided \p Buffer. When writing a subset of the index
431   /// for a distributed backend, provide a \p ModuleToSummariesForIndex map.
432   IndexBitcodeWriter(BitstreamWriter &Stream, StringTableBuilder &StrtabBuilder,
433                      const ModuleSummaryIndex &Index,
434                      const std::map<std::string, GVSummaryMapTy>
435                          *ModuleToSummariesForIndex = nullptr)
436       : BitcodeWriterBase(Stream, StrtabBuilder), Index(Index),
437         ModuleToSummariesForIndex(ModuleToSummariesForIndex) {
438     // Assign unique value ids to all summaries to be written, for use
439     // in writing out the call graph edges. Save the mapping from GUID
440     // to the new global value id to use when writing those edges, which
441     // are currently saved in the index in terms of GUID.
442     forEachSummary([&](GVInfo I, bool) {
443       GUIDToValueIdMap[I.first] = ++GlobalValueId;
444     });
445   }
446 
447   /// The below iterator returns the GUID and associated summary.
448   using GVInfo = std::pair<GlobalValue::GUID, GlobalValueSummary *>;
449 
450   /// Calls the callback for each value GUID and summary to be written to
451   /// bitcode. This hides the details of whether they are being pulled from the
452   /// entire index or just those in a provided ModuleToSummariesForIndex map.
453   template<typename Functor>
454   void forEachSummary(Functor Callback) {
455     if (ModuleToSummariesForIndex) {
456       for (auto &M : *ModuleToSummariesForIndex)
457         for (auto &Summary : M.second) {
458           Callback(Summary, false);
459           // Ensure aliasee is handled, e.g. for assigning a valueId,
460           // even if we are not importing the aliasee directly (the
461           // imported alias will contain a copy of aliasee).
462           if (auto *AS = dyn_cast<AliasSummary>(Summary.getSecond()))
463             Callback({AS->getAliaseeGUID(), &AS->getAliasee()}, true);
464         }
465     } else {
466       for (auto &Summaries : Index)
467         for (auto &Summary : Summaries.second.SummaryList)
468           Callback({Summaries.first, Summary.get()}, false);
469     }
470   }
471 
472   /// Calls the callback for each entry in the modulePaths StringMap that
473   /// should be written to the module path string table. This hides the details
474   /// of whether they are being pulled from the entire index or just those in a
475   /// provided ModuleToSummariesForIndex map.
476   template <typename Functor> void forEachModule(Functor Callback) {
477     if (ModuleToSummariesForIndex) {
478       for (const auto &M : *ModuleToSummariesForIndex) {
479         const auto &MPI = Index.modulePaths().find(M.first);
480         if (MPI == Index.modulePaths().end()) {
481           // This should only happen if the bitcode file was empty, in which
482           // case we shouldn't be importing (the ModuleToSummariesForIndex
483           // would only include the module we are writing and index for).
484           assert(ModuleToSummariesForIndex->size() == 1);
485           continue;
486         }
487         Callback(*MPI);
488       }
489     } else {
490       for (const auto &MPSE : Index.modulePaths())
491         Callback(MPSE);
492     }
493   }
494 
495   /// Main entry point for writing a combined index to bitcode.
496   void write();
497 
498 private:
499   void writeModStrings();
500   void writeCombinedGlobalValueSummary();
501 
502   Optional<unsigned> getValueId(GlobalValue::GUID ValGUID) {
503     auto VMI = GUIDToValueIdMap.find(ValGUID);
504     if (VMI == GUIDToValueIdMap.end())
505       return None;
506     return VMI->second;
507   }
508 
509   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
510 };
511 
512 } // end anonymous namespace
513 
514 static unsigned getEncodedCastOpcode(unsigned Opcode) {
515   switch (Opcode) {
516   default: llvm_unreachable("Unknown cast instruction!");
517   case Instruction::Trunc   : return bitc::CAST_TRUNC;
518   case Instruction::ZExt    : return bitc::CAST_ZEXT;
519   case Instruction::SExt    : return bitc::CAST_SEXT;
520   case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
521   case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
522   case Instruction::UIToFP  : return bitc::CAST_UITOFP;
523   case Instruction::SIToFP  : return bitc::CAST_SITOFP;
524   case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
525   case Instruction::FPExt   : return bitc::CAST_FPEXT;
526   case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
527   case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
528   case Instruction::BitCast : return bitc::CAST_BITCAST;
529   case Instruction::AddrSpaceCast: return bitc::CAST_ADDRSPACECAST;
530   }
531 }
532 
533 static unsigned getEncodedUnaryOpcode(unsigned Opcode) {
534   switch (Opcode) {
535   default: llvm_unreachable("Unknown binary instruction!");
536   case Instruction::FNeg: return bitc::UNOP_FNEG;
537   }
538 }
539 
540 static unsigned getEncodedBinaryOpcode(unsigned Opcode) {
541   switch (Opcode) {
542   default: llvm_unreachable("Unknown binary instruction!");
543   case Instruction::Add:
544   case Instruction::FAdd: return bitc::BINOP_ADD;
545   case Instruction::Sub:
546   case Instruction::FSub: return bitc::BINOP_SUB;
547   case Instruction::Mul:
548   case Instruction::FMul: return bitc::BINOP_MUL;
549   case Instruction::UDiv: return bitc::BINOP_UDIV;
550   case Instruction::FDiv:
551   case Instruction::SDiv: return bitc::BINOP_SDIV;
552   case Instruction::URem: return bitc::BINOP_UREM;
553   case Instruction::FRem:
554   case Instruction::SRem: return bitc::BINOP_SREM;
555   case Instruction::Shl:  return bitc::BINOP_SHL;
556   case Instruction::LShr: return bitc::BINOP_LSHR;
557   case Instruction::AShr: return bitc::BINOP_ASHR;
558   case Instruction::And:  return bitc::BINOP_AND;
559   case Instruction::Or:   return bitc::BINOP_OR;
560   case Instruction::Xor:  return bitc::BINOP_XOR;
561   }
562 }
563 
564 static unsigned getEncodedRMWOperation(AtomicRMWInst::BinOp Op) {
565   switch (Op) {
566   default: llvm_unreachable("Unknown RMW operation!");
567   case AtomicRMWInst::Xchg: return bitc::RMW_XCHG;
568   case AtomicRMWInst::Add: return bitc::RMW_ADD;
569   case AtomicRMWInst::Sub: return bitc::RMW_SUB;
570   case AtomicRMWInst::And: return bitc::RMW_AND;
571   case AtomicRMWInst::Nand: return bitc::RMW_NAND;
572   case AtomicRMWInst::Or: return bitc::RMW_OR;
573   case AtomicRMWInst::Xor: return bitc::RMW_XOR;
574   case AtomicRMWInst::Max: return bitc::RMW_MAX;
575   case AtomicRMWInst::Min: return bitc::RMW_MIN;
576   case AtomicRMWInst::UMax: return bitc::RMW_UMAX;
577   case AtomicRMWInst::UMin: return bitc::RMW_UMIN;
578   case AtomicRMWInst::FAdd: return bitc::RMW_FADD;
579   case AtomicRMWInst::FSub: return bitc::RMW_FSUB;
580   case AtomicRMWInst::FMax: return bitc::RMW_FMAX;
581   case AtomicRMWInst::FMin: return bitc::RMW_FMIN;
582   }
583 }
584 
585 static unsigned getEncodedOrdering(AtomicOrdering Ordering) {
586   switch (Ordering) {
587   case AtomicOrdering::NotAtomic: return bitc::ORDERING_NOTATOMIC;
588   case AtomicOrdering::Unordered: return bitc::ORDERING_UNORDERED;
589   case AtomicOrdering::Monotonic: return bitc::ORDERING_MONOTONIC;
590   case AtomicOrdering::Acquire: return bitc::ORDERING_ACQUIRE;
591   case AtomicOrdering::Release: return bitc::ORDERING_RELEASE;
592   case AtomicOrdering::AcquireRelease: return bitc::ORDERING_ACQREL;
593   case AtomicOrdering::SequentiallyConsistent: return bitc::ORDERING_SEQCST;
594   }
595   llvm_unreachable("Invalid ordering");
596 }
597 
598 static void writeStringRecord(BitstreamWriter &Stream, unsigned Code,
599                               StringRef Str, unsigned AbbrevToUse) {
600   SmallVector<unsigned, 64> Vals;
601 
602   // Code: [strchar x N]
603   for (char C : Str) {
604     if (AbbrevToUse && !BitCodeAbbrevOp::isChar6(C))
605       AbbrevToUse = 0;
606     Vals.push_back(C);
607   }
608 
609   // Emit the finished record.
610   Stream.EmitRecord(Code, Vals, AbbrevToUse);
611 }
612 
613 static uint64_t getAttrKindEncoding(Attribute::AttrKind Kind) {
614   switch (Kind) {
615   case Attribute::Alignment:
616     return bitc::ATTR_KIND_ALIGNMENT;
617   case Attribute::AllocAlign:
618     return bitc::ATTR_KIND_ALLOC_ALIGN;
619   case Attribute::AllocSize:
620     return bitc::ATTR_KIND_ALLOC_SIZE;
621   case Attribute::AlwaysInline:
622     return bitc::ATTR_KIND_ALWAYS_INLINE;
623   case Attribute::Builtin:
624     return bitc::ATTR_KIND_BUILTIN;
625   case Attribute::ByVal:
626     return bitc::ATTR_KIND_BY_VAL;
627   case Attribute::Convergent:
628     return bitc::ATTR_KIND_CONVERGENT;
629   case Attribute::InAlloca:
630     return bitc::ATTR_KIND_IN_ALLOCA;
631   case Attribute::Cold:
632     return bitc::ATTR_KIND_COLD;
633   case Attribute::DisableSanitizerInstrumentation:
634     return bitc::ATTR_KIND_DISABLE_SANITIZER_INSTRUMENTATION;
635   case Attribute::FnRetThunkExtern:
636     return bitc::ATTR_KIND_FNRETTHUNK_EXTERN;
637   case Attribute::Hot:
638     return bitc::ATTR_KIND_HOT;
639   case Attribute::ElementType:
640     return bitc::ATTR_KIND_ELEMENTTYPE;
641   case Attribute::InlineHint:
642     return bitc::ATTR_KIND_INLINE_HINT;
643   case Attribute::InReg:
644     return bitc::ATTR_KIND_IN_REG;
645   case Attribute::JumpTable:
646     return bitc::ATTR_KIND_JUMP_TABLE;
647   case Attribute::MinSize:
648     return bitc::ATTR_KIND_MIN_SIZE;
649   case Attribute::AllocatedPointer:
650     return bitc::ATTR_KIND_ALLOCATED_POINTER;
651   case Attribute::AllocKind:
652     return bitc::ATTR_KIND_ALLOC_KIND;
653   case Attribute::Memory:
654     return bitc::ATTR_KIND_MEMORY;
655   case Attribute::Naked:
656     return bitc::ATTR_KIND_NAKED;
657   case Attribute::Nest:
658     return bitc::ATTR_KIND_NEST;
659   case Attribute::NoAlias:
660     return bitc::ATTR_KIND_NO_ALIAS;
661   case Attribute::NoBuiltin:
662     return bitc::ATTR_KIND_NO_BUILTIN;
663   case Attribute::NoCallback:
664     return bitc::ATTR_KIND_NO_CALLBACK;
665   case Attribute::NoCapture:
666     return bitc::ATTR_KIND_NO_CAPTURE;
667   case Attribute::NoDuplicate:
668     return bitc::ATTR_KIND_NO_DUPLICATE;
669   case Attribute::NoFree:
670     return bitc::ATTR_KIND_NOFREE;
671   case Attribute::NoImplicitFloat:
672     return bitc::ATTR_KIND_NO_IMPLICIT_FLOAT;
673   case Attribute::NoInline:
674     return bitc::ATTR_KIND_NO_INLINE;
675   case Attribute::NoRecurse:
676     return bitc::ATTR_KIND_NO_RECURSE;
677   case Attribute::NoMerge:
678     return bitc::ATTR_KIND_NO_MERGE;
679   case Attribute::NonLazyBind:
680     return bitc::ATTR_KIND_NON_LAZY_BIND;
681   case Attribute::NonNull:
682     return bitc::ATTR_KIND_NON_NULL;
683   case Attribute::Dereferenceable:
684     return bitc::ATTR_KIND_DEREFERENCEABLE;
685   case Attribute::DereferenceableOrNull:
686     return bitc::ATTR_KIND_DEREFERENCEABLE_OR_NULL;
687   case Attribute::NoRedZone:
688     return bitc::ATTR_KIND_NO_RED_ZONE;
689   case Attribute::NoReturn:
690     return bitc::ATTR_KIND_NO_RETURN;
691   case Attribute::NoSync:
692     return bitc::ATTR_KIND_NOSYNC;
693   case Attribute::NoCfCheck:
694     return bitc::ATTR_KIND_NOCF_CHECK;
695   case Attribute::NoProfile:
696     return bitc::ATTR_KIND_NO_PROFILE;
697   case Attribute::SkipProfile:
698     return bitc::ATTR_KIND_SKIP_PROFILE;
699   case Attribute::NoUnwind:
700     return bitc::ATTR_KIND_NO_UNWIND;
701   case Attribute::NoSanitizeBounds:
702     return bitc::ATTR_KIND_NO_SANITIZE_BOUNDS;
703   case Attribute::NoSanitizeCoverage:
704     return bitc::ATTR_KIND_NO_SANITIZE_COVERAGE;
705   case Attribute::NullPointerIsValid:
706     return bitc::ATTR_KIND_NULL_POINTER_IS_VALID;
707   case Attribute::OptForFuzzing:
708     return bitc::ATTR_KIND_OPT_FOR_FUZZING;
709   case Attribute::OptimizeForSize:
710     return bitc::ATTR_KIND_OPTIMIZE_FOR_SIZE;
711   case Attribute::OptimizeNone:
712     return bitc::ATTR_KIND_OPTIMIZE_NONE;
713   case Attribute::ReadNone:
714     return bitc::ATTR_KIND_READ_NONE;
715   case Attribute::ReadOnly:
716     return bitc::ATTR_KIND_READ_ONLY;
717   case Attribute::Returned:
718     return bitc::ATTR_KIND_RETURNED;
719   case Attribute::ReturnsTwice:
720     return bitc::ATTR_KIND_RETURNS_TWICE;
721   case Attribute::SExt:
722     return bitc::ATTR_KIND_S_EXT;
723   case Attribute::Speculatable:
724     return bitc::ATTR_KIND_SPECULATABLE;
725   case Attribute::StackAlignment:
726     return bitc::ATTR_KIND_STACK_ALIGNMENT;
727   case Attribute::StackProtect:
728     return bitc::ATTR_KIND_STACK_PROTECT;
729   case Attribute::StackProtectReq:
730     return bitc::ATTR_KIND_STACK_PROTECT_REQ;
731   case Attribute::StackProtectStrong:
732     return bitc::ATTR_KIND_STACK_PROTECT_STRONG;
733   case Attribute::SafeStack:
734     return bitc::ATTR_KIND_SAFESTACK;
735   case Attribute::ShadowCallStack:
736     return bitc::ATTR_KIND_SHADOWCALLSTACK;
737   case Attribute::StrictFP:
738     return bitc::ATTR_KIND_STRICT_FP;
739   case Attribute::StructRet:
740     return bitc::ATTR_KIND_STRUCT_RET;
741   case Attribute::SanitizeAddress:
742     return bitc::ATTR_KIND_SANITIZE_ADDRESS;
743   case Attribute::SanitizeHWAddress:
744     return bitc::ATTR_KIND_SANITIZE_HWADDRESS;
745   case Attribute::SanitizeThread:
746     return bitc::ATTR_KIND_SANITIZE_THREAD;
747   case Attribute::SanitizeMemory:
748     return bitc::ATTR_KIND_SANITIZE_MEMORY;
749   case Attribute::SpeculativeLoadHardening:
750     return bitc::ATTR_KIND_SPECULATIVE_LOAD_HARDENING;
751   case Attribute::SwiftError:
752     return bitc::ATTR_KIND_SWIFT_ERROR;
753   case Attribute::SwiftSelf:
754     return bitc::ATTR_KIND_SWIFT_SELF;
755   case Attribute::SwiftAsync:
756     return bitc::ATTR_KIND_SWIFT_ASYNC;
757   case Attribute::UWTable:
758     return bitc::ATTR_KIND_UW_TABLE;
759   case Attribute::VScaleRange:
760     return bitc::ATTR_KIND_VSCALE_RANGE;
761   case Attribute::WillReturn:
762     return bitc::ATTR_KIND_WILLRETURN;
763   case Attribute::WriteOnly:
764     return bitc::ATTR_KIND_WRITEONLY;
765   case Attribute::ZExt:
766     return bitc::ATTR_KIND_Z_EXT;
767   case Attribute::ImmArg:
768     return bitc::ATTR_KIND_IMMARG;
769   case Attribute::SanitizeMemTag:
770     return bitc::ATTR_KIND_SANITIZE_MEMTAG;
771   case Attribute::Preallocated:
772     return bitc::ATTR_KIND_PREALLOCATED;
773   case Attribute::NoUndef:
774     return bitc::ATTR_KIND_NOUNDEF;
775   case Attribute::ByRef:
776     return bitc::ATTR_KIND_BYREF;
777   case Attribute::MustProgress:
778     return bitc::ATTR_KIND_MUSTPROGRESS;
779   case Attribute::PresplitCoroutine:
780     return bitc::ATTR_KIND_PRESPLIT_COROUTINE;
781   case Attribute::EndAttrKinds:
782     llvm_unreachable("Can not encode end-attribute kinds marker.");
783   case Attribute::None:
784     llvm_unreachable("Can not encode none-attribute.");
785   case Attribute::EmptyKey:
786   case Attribute::TombstoneKey:
787     llvm_unreachable("Trying to encode EmptyKey/TombstoneKey");
788   }
789 
790   llvm_unreachable("Trying to encode unknown attribute");
791 }
792 
793 void ModuleBitcodeWriter::writeAttributeGroupTable() {
794   const std::vector<ValueEnumerator::IndexAndAttrSet> &AttrGrps =
795       VE.getAttributeGroups();
796   if (AttrGrps.empty()) return;
797 
798   Stream.EnterSubblock(bitc::PARAMATTR_GROUP_BLOCK_ID, 3);
799 
800   SmallVector<uint64_t, 64> Record;
801   for (ValueEnumerator::IndexAndAttrSet Pair : AttrGrps) {
802     unsigned AttrListIndex = Pair.first;
803     AttributeSet AS = Pair.second;
804     Record.push_back(VE.getAttributeGroupID(Pair));
805     Record.push_back(AttrListIndex);
806 
807     for (Attribute Attr : AS) {
808       if (Attr.isEnumAttribute()) {
809         Record.push_back(0);
810         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
811       } else if (Attr.isIntAttribute()) {
812         Record.push_back(1);
813         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
814         Record.push_back(Attr.getValueAsInt());
815       } else if (Attr.isStringAttribute()) {
816         StringRef Kind = Attr.getKindAsString();
817         StringRef Val = Attr.getValueAsString();
818 
819         Record.push_back(Val.empty() ? 3 : 4);
820         Record.append(Kind.begin(), Kind.end());
821         Record.push_back(0);
822         if (!Val.empty()) {
823           Record.append(Val.begin(), Val.end());
824           Record.push_back(0);
825         }
826       } else {
827         assert(Attr.isTypeAttribute());
828         Type *Ty = Attr.getValueAsType();
829         Record.push_back(Ty ? 6 : 5);
830         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
831         if (Ty)
832           Record.push_back(VE.getTypeID(Attr.getValueAsType()));
833       }
834     }
835 
836     Stream.EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
837     Record.clear();
838   }
839 
840   Stream.ExitBlock();
841 }
842 
843 void ModuleBitcodeWriter::writeAttributeTable() {
844   const std::vector<AttributeList> &Attrs = VE.getAttributeLists();
845   if (Attrs.empty()) return;
846 
847   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
848 
849   SmallVector<uint64_t, 64> Record;
850   for (const AttributeList &AL : Attrs) {
851     for (unsigned i : AL.indexes()) {
852       AttributeSet AS = AL.getAttributes(i);
853       if (AS.hasAttributes())
854         Record.push_back(VE.getAttributeGroupID({i, AS}));
855     }
856 
857     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
858     Record.clear();
859   }
860 
861   Stream.ExitBlock();
862 }
863 
864 /// WriteTypeTable - Write out the type table for a module.
865 void ModuleBitcodeWriter::writeTypeTable() {
866   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
867 
868   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
869   SmallVector<uint64_t, 64> TypeVals;
870 
871   uint64_t NumBits = VE.computeBitsRequiredForTypeIndicies();
872 
873   // Abbrev for TYPE_CODE_POINTER.
874   auto Abbv = std::make_shared<BitCodeAbbrev>();
875   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
876   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
877   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
878   unsigned PtrAbbrev = Stream.EmitAbbrev(std::move(Abbv));
879 
880   // Abbrev for TYPE_CODE_OPAQUE_POINTER.
881   Abbv = std::make_shared<BitCodeAbbrev>();
882   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_OPAQUE_POINTER));
883   Abbv->Add(BitCodeAbbrevOp(0)); // Addrspace = 0
884   unsigned OpaquePtrAbbrev = Stream.EmitAbbrev(std::move(Abbv));
885 
886   // Abbrev for TYPE_CODE_FUNCTION.
887   Abbv = std::make_shared<BitCodeAbbrev>();
888   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
889   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
890   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
891   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
892   unsigned FunctionAbbrev = Stream.EmitAbbrev(std::move(Abbv));
893 
894   // Abbrev for TYPE_CODE_STRUCT_ANON.
895   Abbv = std::make_shared<BitCodeAbbrev>();
896   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
897   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
898   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
899   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
900   unsigned StructAnonAbbrev = Stream.EmitAbbrev(std::move(Abbv));
901 
902   // Abbrev for TYPE_CODE_STRUCT_NAME.
903   Abbv = std::make_shared<BitCodeAbbrev>();
904   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
905   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
906   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
907   unsigned StructNameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
908 
909   // Abbrev for TYPE_CODE_STRUCT_NAMED.
910   Abbv = std::make_shared<BitCodeAbbrev>();
911   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
912   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
913   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
914   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
915   unsigned StructNamedAbbrev = Stream.EmitAbbrev(std::move(Abbv));
916 
917   // Abbrev for TYPE_CODE_ARRAY.
918   Abbv = std::make_shared<BitCodeAbbrev>();
919   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
920   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
921   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
922   unsigned ArrayAbbrev = Stream.EmitAbbrev(std::move(Abbv));
923 
924   // Emit an entry count so the reader can reserve space.
925   TypeVals.push_back(TypeList.size());
926   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
927   TypeVals.clear();
928 
929   // Loop over all of the types, emitting each in turn.
930   for (Type *T : TypeList) {
931     int AbbrevToUse = 0;
932     unsigned Code = 0;
933 
934     switch (T->getTypeID()) {
935     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;      break;
936     case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;      break;
937     case Type::BFloatTyID:    Code = bitc::TYPE_CODE_BFLOAT;    break;
938     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;     break;
939     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE;    break;
940     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80;  break;
941     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128;     break;
942     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
943     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;     break;
944     case Type::MetadataTyID:  Code = bitc::TYPE_CODE_METADATA;  break;
945     case Type::X86_MMXTyID:   Code = bitc::TYPE_CODE_X86_MMX;   break;
946     case Type::X86_AMXTyID:   Code = bitc::TYPE_CODE_X86_AMX;   break;
947     case Type::TokenTyID:     Code = bitc::TYPE_CODE_TOKEN;     break;
948     case Type::IntegerTyID:
949       // INTEGER: [width]
950       Code = bitc::TYPE_CODE_INTEGER;
951       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
952       break;
953     case Type::PointerTyID: {
954       PointerType *PTy = cast<PointerType>(T);
955       unsigned AddressSpace = PTy->getAddressSpace();
956       if (PTy->isOpaque()) {
957         // OPAQUE_POINTER: [address space]
958         Code = bitc::TYPE_CODE_OPAQUE_POINTER;
959         TypeVals.push_back(AddressSpace);
960         if (AddressSpace == 0)
961           AbbrevToUse = OpaquePtrAbbrev;
962       } else {
963         // POINTER: [pointee type, address space]
964         Code = bitc::TYPE_CODE_POINTER;
965         TypeVals.push_back(VE.getTypeID(PTy->getNonOpaquePointerElementType()));
966         TypeVals.push_back(AddressSpace);
967         if (AddressSpace == 0)
968           AbbrevToUse = PtrAbbrev;
969       }
970       break;
971     }
972     case Type::FunctionTyID: {
973       FunctionType *FT = cast<FunctionType>(T);
974       // FUNCTION: [isvararg, retty, paramty x N]
975       Code = bitc::TYPE_CODE_FUNCTION;
976       TypeVals.push_back(FT->isVarArg());
977       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
978       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
979         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
980       AbbrevToUse = FunctionAbbrev;
981       break;
982     }
983     case Type::StructTyID: {
984       StructType *ST = cast<StructType>(T);
985       // STRUCT: [ispacked, eltty x N]
986       TypeVals.push_back(ST->isPacked());
987       // Output all of the element types.
988       for (Type *ET : ST->elements())
989         TypeVals.push_back(VE.getTypeID(ET));
990 
991       if (ST->isLiteral()) {
992         Code = bitc::TYPE_CODE_STRUCT_ANON;
993         AbbrevToUse = StructAnonAbbrev;
994       } else {
995         if (ST->isOpaque()) {
996           Code = bitc::TYPE_CODE_OPAQUE;
997         } else {
998           Code = bitc::TYPE_CODE_STRUCT_NAMED;
999           AbbrevToUse = StructNamedAbbrev;
1000         }
1001 
1002         // Emit the name if it is present.
1003         if (!ST->getName().empty())
1004           writeStringRecord(Stream, bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
1005                             StructNameAbbrev);
1006       }
1007       break;
1008     }
1009     case Type::ArrayTyID: {
1010       ArrayType *AT = cast<ArrayType>(T);
1011       // ARRAY: [numelts, eltty]
1012       Code = bitc::TYPE_CODE_ARRAY;
1013       TypeVals.push_back(AT->getNumElements());
1014       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
1015       AbbrevToUse = ArrayAbbrev;
1016       break;
1017     }
1018     case Type::FixedVectorTyID:
1019     case Type::ScalableVectorTyID: {
1020       VectorType *VT = cast<VectorType>(T);
1021       // VECTOR [numelts, eltty] or
1022       //        [numelts, eltty, scalable]
1023       Code = bitc::TYPE_CODE_VECTOR;
1024       TypeVals.push_back(VT->getElementCount().getKnownMinValue());
1025       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
1026       if (isa<ScalableVectorType>(VT))
1027         TypeVals.push_back(true);
1028       break;
1029     }
1030     case Type::TypedPointerTyID:
1031       llvm_unreachable("Typed pointers cannot be added to IR modules");
1032     }
1033 
1034     // Emit the finished record.
1035     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
1036     TypeVals.clear();
1037   }
1038 
1039   Stream.ExitBlock();
1040 }
1041 
1042 static unsigned getEncodedLinkage(const GlobalValue::LinkageTypes Linkage) {
1043   switch (Linkage) {
1044   case GlobalValue::ExternalLinkage:
1045     return 0;
1046   case GlobalValue::WeakAnyLinkage:
1047     return 16;
1048   case GlobalValue::AppendingLinkage:
1049     return 2;
1050   case GlobalValue::InternalLinkage:
1051     return 3;
1052   case GlobalValue::LinkOnceAnyLinkage:
1053     return 18;
1054   case GlobalValue::ExternalWeakLinkage:
1055     return 7;
1056   case GlobalValue::CommonLinkage:
1057     return 8;
1058   case GlobalValue::PrivateLinkage:
1059     return 9;
1060   case GlobalValue::WeakODRLinkage:
1061     return 17;
1062   case GlobalValue::LinkOnceODRLinkage:
1063     return 19;
1064   case GlobalValue::AvailableExternallyLinkage:
1065     return 12;
1066   }
1067   llvm_unreachable("Invalid linkage");
1068 }
1069 
1070 static unsigned getEncodedLinkage(const GlobalValue &GV) {
1071   return getEncodedLinkage(GV.getLinkage());
1072 }
1073 
1074 static uint64_t getEncodedFFlags(FunctionSummary::FFlags Flags) {
1075   uint64_t RawFlags = 0;
1076   RawFlags |= Flags.ReadNone;
1077   RawFlags |= (Flags.ReadOnly << 1);
1078   RawFlags |= (Flags.NoRecurse << 2);
1079   RawFlags |= (Flags.ReturnDoesNotAlias << 3);
1080   RawFlags |= (Flags.NoInline << 4);
1081   RawFlags |= (Flags.AlwaysInline << 5);
1082   RawFlags |= (Flags.NoUnwind << 6);
1083   RawFlags |= (Flags.MayThrow << 7);
1084   RawFlags |= (Flags.HasUnknownCall << 8);
1085   RawFlags |= (Flags.MustBeUnreachable << 9);
1086   return RawFlags;
1087 }
1088 
1089 // Decode the flags for GlobalValue in the summary. See getDecodedGVSummaryFlags
1090 // in BitcodeReader.cpp.
1091 static uint64_t getEncodedGVSummaryFlags(GlobalValueSummary::GVFlags Flags) {
1092   uint64_t RawFlags = 0;
1093 
1094   RawFlags |= Flags.NotEligibleToImport; // bool
1095   RawFlags |= (Flags.Live << 1);
1096   RawFlags |= (Flags.DSOLocal << 2);
1097   RawFlags |= (Flags.CanAutoHide << 3);
1098 
1099   // Linkage don't need to be remapped at that time for the summary. Any future
1100   // change to the getEncodedLinkage() function will need to be taken into
1101   // account here as well.
1102   RawFlags = (RawFlags << 4) | Flags.Linkage; // 4 bits
1103 
1104   RawFlags |= (Flags.Visibility << 8); // 2 bits
1105 
1106   return RawFlags;
1107 }
1108 
1109 static uint64_t getEncodedGVarFlags(GlobalVarSummary::GVarFlags Flags) {
1110   uint64_t RawFlags = Flags.MaybeReadOnly | (Flags.MaybeWriteOnly << 1) |
1111                       (Flags.Constant << 2) | Flags.VCallVisibility << 3;
1112   return RawFlags;
1113 }
1114 
1115 static unsigned getEncodedVisibility(const GlobalValue &GV) {
1116   switch (GV.getVisibility()) {
1117   case GlobalValue::DefaultVisibility:   return 0;
1118   case GlobalValue::HiddenVisibility:    return 1;
1119   case GlobalValue::ProtectedVisibility: return 2;
1120   }
1121   llvm_unreachable("Invalid visibility");
1122 }
1123 
1124 static unsigned getEncodedDLLStorageClass(const GlobalValue &GV) {
1125   switch (GV.getDLLStorageClass()) {
1126   case GlobalValue::DefaultStorageClass:   return 0;
1127   case GlobalValue::DLLImportStorageClass: return 1;
1128   case GlobalValue::DLLExportStorageClass: return 2;
1129   }
1130   llvm_unreachable("Invalid DLL storage class");
1131 }
1132 
1133 static unsigned getEncodedThreadLocalMode(const GlobalValue &GV) {
1134   switch (GV.getThreadLocalMode()) {
1135     case GlobalVariable::NotThreadLocal:         return 0;
1136     case GlobalVariable::GeneralDynamicTLSModel: return 1;
1137     case GlobalVariable::LocalDynamicTLSModel:   return 2;
1138     case GlobalVariable::InitialExecTLSModel:    return 3;
1139     case GlobalVariable::LocalExecTLSModel:      return 4;
1140   }
1141   llvm_unreachable("Invalid TLS model");
1142 }
1143 
1144 static unsigned getEncodedComdatSelectionKind(const Comdat &C) {
1145   switch (C.getSelectionKind()) {
1146   case Comdat::Any:
1147     return bitc::COMDAT_SELECTION_KIND_ANY;
1148   case Comdat::ExactMatch:
1149     return bitc::COMDAT_SELECTION_KIND_EXACT_MATCH;
1150   case Comdat::Largest:
1151     return bitc::COMDAT_SELECTION_KIND_LARGEST;
1152   case Comdat::NoDeduplicate:
1153     return bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES;
1154   case Comdat::SameSize:
1155     return bitc::COMDAT_SELECTION_KIND_SAME_SIZE;
1156   }
1157   llvm_unreachable("Invalid selection kind");
1158 }
1159 
1160 static unsigned getEncodedUnnamedAddr(const GlobalValue &GV) {
1161   switch (GV.getUnnamedAddr()) {
1162   case GlobalValue::UnnamedAddr::None:   return 0;
1163   case GlobalValue::UnnamedAddr::Local:  return 2;
1164   case GlobalValue::UnnamedAddr::Global: return 1;
1165   }
1166   llvm_unreachable("Invalid unnamed_addr");
1167 }
1168 
1169 size_t ModuleBitcodeWriter::addToStrtab(StringRef Str) {
1170   if (GenerateHash)
1171     Hasher.update(Str);
1172   return StrtabBuilder.add(Str);
1173 }
1174 
1175 void ModuleBitcodeWriter::writeComdats() {
1176   SmallVector<unsigned, 64> Vals;
1177   for (const Comdat *C : VE.getComdats()) {
1178     // COMDAT: [strtab offset, strtab size, selection_kind]
1179     Vals.push_back(addToStrtab(C->getName()));
1180     Vals.push_back(C->getName().size());
1181     Vals.push_back(getEncodedComdatSelectionKind(*C));
1182     Stream.EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
1183     Vals.clear();
1184   }
1185 }
1186 
1187 /// Write a record that will eventually hold the word offset of the
1188 /// module-level VST. For now the offset is 0, which will be backpatched
1189 /// after the real VST is written. Saves the bit offset to backpatch.
1190 void ModuleBitcodeWriter::writeValueSymbolTableForwardDecl() {
1191   // Write a placeholder value in for the offset of the real VST,
1192   // which is written after the function blocks so that it can include
1193   // the offset of each function. The placeholder offset will be
1194   // updated when the real VST is written.
1195   auto Abbv = std::make_shared<BitCodeAbbrev>();
1196   Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_VSTOFFSET));
1197   // Blocks are 32-bit aligned, so we can use a 32-bit word offset to
1198   // hold the real VST offset. Must use fixed instead of VBR as we don't
1199   // know how many VBR chunks to reserve ahead of time.
1200   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
1201   unsigned VSTOffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1202 
1203   // Emit the placeholder
1204   uint64_t Vals[] = {bitc::MODULE_CODE_VSTOFFSET, 0};
1205   Stream.EmitRecordWithAbbrev(VSTOffsetAbbrev, Vals);
1206 
1207   // Compute and save the bit offset to the placeholder, which will be
1208   // patched when the real VST is written. We can simply subtract the 32-bit
1209   // fixed size from the current bit number to get the location to backpatch.
1210   VSTOffsetPlaceholder = Stream.GetCurrentBitNo() - 32;
1211 }
1212 
1213 enum StringEncoding { SE_Char6, SE_Fixed7, SE_Fixed8 };
1214 
1215 /// Determine the encoding to use for the given string name and length.
1216 static StringEncoding getStringEncoding(StringRef Str) {
1217   bool isChar6 = true;
1218   for (char C : Str) {
1219     if (isChar6)
1220       isChar6 = BitCodeAbbrevOp::isChar6(C);
1221     if ((unsigned char)C & 128)
1222       // don't bother scanning the rest.
1223       return SE_Fixed8;
1224   }
1225   if (isChar6)
1226     return SE_Char6;
1227   return SE_Fixed7;
1228 }
1229 
1230 static_assert(sizeof(GlobalValue::SanitizerMetadata) <= sizeof(unsigned),
1231               "Sanitizer Metadata is too large for naive serialization.");
1232 static unsigned
1233 serializeSanitizerMetadata(const GlobalValue::SanitizerMetadata &Meta) {
1234   return Meta.NoAddress | (Meta.NoHWAddress << 1) |
1235          (Meta.Memtag << 2) | (Meta.IsDynInit << 3);
1236 }
1237 
1238 /// Emit top-level description of module, including target triple, inline asm,
1239 /// descriptors for global variables, and function prototype info.
1240 /// Returns the bit offset to backpatch with the location of the real VST.
1241 void ModuleBitcodeWriter::writeModuleInfo() {
1242   // Emit various pieces of data attached to a module.
1243   if (!M.getTargetTriple().empty())
1244     writeStringRecord(Stream, bitc::MODULE_CODE_TRIPLE, M.getTargetTriple(),
1245                       0 /*TODO*/);
1246   const std::string &DL = M.getDataLayoutStr();
1247   if (!DL.empty())
1248     writeStringRecord(Stream, bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/);
1249   if (!M.getModuleInlineAsm().empty())
1250     writeStringRecord(Stream, bitc::MODULE_CODE_ASM, M.getModuleInlineAsm(),
1251                       0 /*TODO*/);
1252 
1253   // Emit information about sections and GC, computing how many there are. Also
1254   // compute the maximum alignment value.
1255   std::map<std::string, unsigned> SectionMap;
1256   std::map<std::string, unsigned> GCMap;
1257   MaybeAlign MaxAlignment;
1258   unsigned MaxGlobalType = 0;
1259   const auto UpdateMaxAlignment = [&MaxAlignment](const MaybeAlign A) {
1260     if (A)
1261       MaxAlignment = !MaxAlignment ? *A : std::max(*MaxAlignment, *A);
1262   };
1263   for (const GlobalVariable &GV : M.globals()) {
1264     UpdateMaxAlignment(GV.getAlign());
1265     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getValueType()));
1266     if (GV.hasSection()) {
1267       // Give section names unique ID's.
1268       unsigned &Entry = SectionMap[std::string(GV.getSection())];
1269       if (!Entry) {
1270         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
1271                           0 /*TODO*/);
1272         Entry = SectionMap.size();
1273       }
1274     }
1275   }
1276   for (const Function &F : M) {
1277     UpdateMaxAlignment(F.getAlign());
1278     if (F.hasSection()) {
1279       // Give section names unique ID's.
1280       unsigned &Entry = SectionMap[std::string(F.getSection())];
1281       if (!Entry) {
1282         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
1283                           0 /*TODO*/);
1284         Entry = SectionMap.size();
1285       }
1286     }
1287     if (F.hasGC()) {
1288       // Same for GC names.
1289       unsigned &Entry = GCMap[F.getGC()];
1290       if (!Entry) {
1291         writeStringRecord(Stream, bitc::MODULE_CODE_GCNAME, F.getGC(),
1292                           0 /*TODO*/);
1293         Entry = GCMap.size();
1294       }
1295     }
1296   }
1297 
1298   // Emit abbrev for globals, now that we know # sections and max alignment.
1299   unsigned SimpleGVarAbbrev = 0;
1300   if (!M.global_empty()) {
1301     // Add an abbrev for common globals with no visibility or thread localness.
1302     auto Abbv = std::make_shared<BitCodeAbbrev>();
1303     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
1304     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1305     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1306     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1307                               Log2_32_Ceil(MaxGlobalType+1)));
1308     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddrSpace << 2
1309                                                            //| explicitType << 1
1310                                                            //| constant
1311     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Initializer.
1312     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // Linkage.
1313     if (!MaxAlignment)                                     // Alignment.
1314       Abbv->Add(BitCodeAbbrevOp(0));
1315     else {
1316       unsigned MaxEncAlignment = getEncodedAlign(MaxAlignment);
1317       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1318                                Log2_32_Ceil(MaxEncAlignment+1)));
1319     }
1320     if (SectionMap.empty())                                    // Section.
1321       Abbv->Add(BitCodeAbbrevOp(0));
1322     else
1323       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1324                                Log2_32_Ceil(SectionMap.size()+1)));
1325     // Don't bother emitting vis + thread local.
1326     SimpleGVarAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1327   }
1328 
1329   SmallVector<unsigned, 64> Vals;
1330   // Emit the module's source file name.
1331   {
1332     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
1333     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
1334     if (Bits == SE_Char6)
1335       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
1336     else if (Bits == SE_Fixed7)
1337       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
1338 
1339     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
1340     auto Abbv = std::make_shared<BitCodeAbbrev>();
1341     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
1342     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1343     Abbv->Add(AbbrevOpToUse);
1344     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1345 
1346     for (const auto P : M.getSourceFileName())
1347       Vals.push_back((unsigned char)P);
1348 
1349     // Emit the finished record.
1350     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
1351     Vals.clear();
1352   }
1353 
1354   // Emit the global variable information.
1355   for (const GlobalVariable &GV : M.globals()) {
1356     unsigned AbbrevToUse = 0;
1357 
1358     // GLOBALVAR: [strtab offset, strtab size, type, isconst, initid,
1359     //             linkage, alignment, section, visibility, threadlocal,
1360     //             unnamed_addr, externally_initialized, dllstorageclass,
1361     //             comdat, attributes, DSO_Local, GlobalSanitizer]
1362     Vals.push_back(addToStrtab(GV.getName()));
1363     Vals.push_back(GV.getName().size());
1364     Vals.push_back(VE.getTypeID(GV.getValueType()));
1365     Vals.push_back(GV.getType()->getAddressSpace() << 2 | 2 | GV.isConstant());
1366     Vals.push_back(GV.isDeclaration() ? 0 :
1367                    (VE.getValueID(GV.getInitializer()) + 1));
1368     Vals.push_back(getEncodedLinkage(GV));
1369     Vals.push_back(getEncodedAlign(GV.getAlign()));
1370     Vals.push_back(GV.hasSection() ? SectionMap[std::string(GV.getSection())]
1371                                    : 0);
1372     if (GV.isThreadLocal() ||
1373         GV.getVisibility() != GlobalValue::DefaultVisibility ||
1374         GV.getUnnamedAddr() != GlobalValue::UnnamedAddr::None ||
1375         GV.isExternallyInitialized() ||
1376         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
1377         GV.hasComdat() || GV.hasAttributes() || GV.isDSOLocal() ||
1378         GV.hasPartition() || GV.hasSanitizerMetadata()) {
1379       Vals.push_back(getEncodedVisibility(GV));
1380       Vals.push_back(getEncodedThreadLocalMode(GV));
1381       Vals.push_back(getEncodedUnnamedAddr(GV));
1382       Vals.push_back(GV.isExternallyInitialized());
1383       Vals.push_back(getEncodedDLLStorageClass(GV));
1384       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
1385 
1386       auto AL = GV.getAttributesAsList(AttributeList::FunctionIndex);
1387       Vals.push_back(VE.getAttributeListID(AL));
1388 
1389       Vals.push_back(GV.isDSOLocal());
1390       Vals.push_back(addToStrtab(GV.getPartition()));
1391       Vals.push_back(GV.getPartition().size());
1392 
1393       Vals.push_back((GV.hasSanitizerMetadata() ? serializeSanitizerMetadata(
1394                                                       GV.getSanitizerMetadata())
1395                                                 : 0));
1396     } else {
1397       AbbrevToUse = SimpleGVarAbbrev;
1398     }
1399 
1400     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
1401     Vals.clear();
1402   }
1403 
1404   // Emit the function proto information.
1405   for (const Function &F : M) {
1406     // FUNCTION:  [strtab offset, strtab size, type, callingconv, isproto,
1407     //             linkage, paramattrs, alignment, section, visibility, gc,
1408     //             unnamed_addr, prologuedata, dllstorageclass, comdat,
1409     //             prefixdata, personalityfn, DSO_Local, addrspace]
1410     Vals.push_back(addToStrtab(F.getName()));
1411     Vals.push_back(F.getName().size());
1412     Vals.push_back(VE.getTypeID(F.getFunctionType()));
1413     Vals.push_back(F.getCallingConv());
1414     Vals.push_back(F.isDeclaration());
1415     Vals.push_back(getEncodedLinkage(F));
1416     Vals.push_back(VE.getAttributeListID(F.getAttributes()));
1417     Vals.push_back(getEncodedAlign(F.getAlign()));
1418     Vals.push_back(F.hasSection() ? SectionMap[std::string(F.getSection())]
1419                                   : 0);
1420     Vals.push_back(getEncodedVisibility(F));
1421     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
1422     Vals.push_back(getEncodedUnnamedAddr(F));
1423     Vals.push_back(F.hasPrologueData() ? (VE.getValueID(F.getPrologueData()) + 1)
1424                                        : 0);
1425     Vals.push_back(getEncodedDLLStorageClass(F));
1426     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
1427     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
1428                                      : 0);
1429     Vals.push_back(
1430         F.hasPersonalityFn() ? (VE.getValueID(F.getPersonalityFn()) + 1) : 0);
1431 
1432     Vals.push_back(F.isDSOLocal());
1433     Vals.push_back(F.getAddressSpace());
1434     Vals.push_back(addToStrtab(F.getPartition()));
1435     Vals.push_back(F.getPartition().size());
1436 
1437     unsigned AbbrevToUse = 0;
1438     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
1439     Vals.clear();
1440   }
1441 
1442   // Emit the alias information.
1443   for (const GlobalAlias &A : M.aliases()) {
1444     // ALIAS: [strtab offset, strtab size, alias type, aliasee val#, linkage,
1445     //         visibility, dllstorageclass, threadlocal, unnamed_addr,
1446     //         DSO_Local]
1447     Vals.push_back(addToStrtab(A.getName()));
1448     Vals.push_back(A.getName().size());
1449     Vals.push_back(VE.getTypeID(A.getValueType()));
1450     Vals.push_back(A.getType()->getAddressSpace());
1451     Vals.push_back(VE.getValueID(A.getAliasee()));
1452     Vals.push_back(getEncodedLinkage(A));
1453     Vals.push_back(getEncodedVisibility(A));
1454     Vals.push_back(getEncodedDLLStorageClass(A));
1455     Vals.push_back(getEncodedThreadLocalMode(A));
1456     Vals.push_back(getEncodedUnnamedAddr(A));
1457     Vals.push_back(A.isDSOLocal());
1458     Vals.push_back(addToStrtab(A.getPartition()));
1459     Vals.push_back(A.getPartition().size());
1460 
1461     unsigned AbbrevToUse = 0;
1462     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
1463     Vals.clear();
1464   }
1465 
1466   // Emit the ifunc information.
1467   for (const GlobalIFunc &I : M.ifuncs()) {
1468     // IFUNC: [strtab offset, strtab size, ifunc type, address space, resolver
1469     //         val#, linkage, visibility, DSO_Local]
1470     Vals.push_back(addToStrtab(I.getName()));
1471     Vals.push_back(I.getName().size());
1472     Vals.push_back(VE.getTypeID(I.getValueType()));
1473     Vals.push_back(I.getType()->getAddressSpace());
1474     Vals.push_back(VE.getValueID(I.getResolver()));
1475     Vals.push_back(getEncodedLinkage(I));
1476     Vals.push_back(getEncodedVisibility(I));
1477     Vals.push_back(I.isDSOLocal());
1478     Vals.push_back(addToStrtab(I.getPartition()));
1479     Vals.push_back(I.getPartition().size());
1480     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
1481     Vals.clear();
1482   }
1483 
1484   writeValueSymbolTableForwardDecl();
1485 }
1486 
1487 static uint64_t getOptimizationFlags(const Value *V) {
1488   uint64_t Flags = 0;
1489 
1490   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
1491     if (OBO->hasNoSignedWrap())
1492       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
1493     if (OBO->hasNoUnsignedWrap())
1494       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
1495   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
1496     if (PEO->isExact())
1497       Flags |= 1 << bitc::PEO_EXACT;
1498   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
1499     if (FPMO->hasAllowReassoc())
1500       Flags |= bitc::AllowReassoc;
1501     if (FPMO->hasNoNaNs())
1502       Flags |= bitc::NoNaNs;
1503     if (FPMO->hasNoInfs())
1504       Flags |= bitc::NoInfs;
1505     if (FPMO->hasNoSignedZeros())
1506       Flags |= bitc::NoSignedZeros;
1507     if (FPMO->hasAllowReciprocal())
1508       Flags |= bitc::AllowReciprocal;
1509     if (FPMO->hasAllowContract())
1510       Flags |= bitc::AllowContract;
1511     if (FPMO->hasApproxFunc())
1512       Flags |= bitc::ApproxFunc;
1513   }
1514 
1515   return Flags;
1516 }
1517 
1518 void ModuleBitcodeWriter::writeValueAsMetadata(
1519     const ValueAsMetadata *MD, SmallVectorImpl<uint64_t> &Record) {
1520   // Mimic an MDNode with a value as one operand.
1521   Value *V = MD->getValue();
1522   Record.push_back(VE.getTypeID(V->getType()));
1523   Record.push_back(VE.getValueID(V));
1524   Stream.EmitRecord(bitc::METADATA_VALUE, Record, 0);
1525   Record.clear();
1526 }
1527 
1528 void ModuleBitcodeWriter::writeMDTuple(const MDTuple *N,
1529                                        SmallVectorImpl<uint64_t> &Record,
1530                                        unsigned Abbrev) {
1531   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
1532     Metadata *MD = N->getOperand(i);
1533     assert(!(MD && isa<LocalAsMetadata>(MD)) &&
1534            "Unexpected function-local metadata");
1535     Record.push_back(VE.getMetadataOrNullID(MD));
1536   }
1537   Stream.EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
1538                                     : bitc::METADATA_NODE,
1539                     Record, Abbrev);
1540   Record.clear();
1541 }
1542 
1543 unsigned ModuleBitcodeWriter::createDILocationAbbrev() {
1544   // Assume the column is usually under 128, and always output the inlined-at
1545   // location (it's never more expensive than building an array size 1).
1546   auto Abbv = std::make_shared<BitCodeAbbrev>();
1547   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
1548   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1549   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1550   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1551   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1552   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1553   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1554   return Stream.EmitAbbrev(std::move(Abbv));
1555 }
1556 
1557 void ModuleBitcodeWriter::writeDILocation(const DILocation *N,
1558                                           SmallVectorImpl<uint64_t> &Record,
1559                                           unsigned &Abbrev) {
1560   if (!Abbrev)
1561     Abbrev = createDILocationAbbrev();
1562 
1563   Record.push_back(N->isDistinct());
1564   Record.push_back(N->getLine());
1565   Record.push_back(N->getColumn());
1566   Record.push_back(VE.getMetadataID(N->getScope()));
1567   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
1568   Record.push_back(N->isImplicitCode());
1569 
1570   Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
1571   Record.clear();
1572 }
1573 
1574 unsigned ModuleBitcodeWriter::createGenericDINodeAbbrev() {
1575   // Assume the column is usually under 128, and always output the inlined-at
1576   // location (it's never more expensive than building an array size 1).
1577   auto Abbv = std::make_shared<BitCodeAbbrev>();
1578   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
1579   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1580   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1581   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1582   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1583   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1584   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1585   return Stream.EmitAbbrev(std::move(Abbv));
1586 }
1587 
1588 void ModuleBitcodeWriter::writeGenericDINode(const GenericDINode *N,
1589                                              SmallVectorImpl<uint64_t> &Record,
1590                                              unsigned &Abbrev) {
1591   if (!Abbrev)
1592     Abbrev = createGenericDINodeAbbrev();
1593 
1594   Record.push_back(N->isDistinct());
1595   Record.push_back(N->getTag());
1596   Record.push_back(0); // Per-tag version field; unused for now.
1597 
1598   for (auto &I : N->operands())
1599     Record.push_back(VE.getMetadataOrNullID(I));
1600 
1601   Stream.EmitRecord(bitc::METADATA_GENERIC_DEBUG, Record, Abbrev);
1602   Record.clear();
1603 }
1604 
1605 void ModuleBitcodeWriter::writeDISubrange(const DISubrange *N,
1606                                           SmallVectorImpl<uint64_t> &Record,
1607                                           unsigned Abbrev) {
1608   const uint64_t Version = 2 << 1;
1609   Record.push_back((uint64_t)N->isDistinct() | Version);
1610   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1611   Record.push_back(VE.getMetadataOrNullID(N->getRawLowerBound()));
1612   Record.push_back(VE.getMetadataOrNullID(N->getRawUpperBound()));
1613   Record.push_back(VE.getMetadataOrNullID(N->getRawStride()));
1614 
1615   Stream.EmitRecord(bitc::METADATA_SUBRANGE, Record, Abbrev);
1616   Record.clear();
1617 }
1618 
1619 void ModuleBitcodeWriter::writeDIGenericSubrange(
1620     const DIGenericSubrange *N, SmallVectorImpl<uint64_t> &Record,
1621     unsigned Abbrev) {
1622   Record.push_back((uint64_t)N->isDistinct());
1623   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1624   Record.push_back(VE.getMetadataOrNullID(N->getRawLowerBound()));
1625   Record.push_back(VE.getMetadataOrNullID(N->getRawUpperBound()));
1626   Record.push_back(VE.getMetadataOrNullID(N->getRawStride()));
1627 
1628   Stream.EmitRecord(bitc::METADATA_GENERIC_SUBRANGE, Record, Abbrev);
1629   Record.clear();
1630 }
1631 
1632 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
1633   if ((int64_t)V >= 0)
1634     Vals.push_back(V << 1);
1635   else
1636     Vals.push_back((-V << 1) | 1);
1637 }
1638 
1639 static void emitWideAPInt(SmallVectorImpl<uint64_t> &Vals, const APInt &A) {
1640   // We have an arbitrary precision integer value to write whose
1641   // bit width is > 64. However, in canonical unsigned integer
1642   // format it is likely that the high bits are going to be zero.
1643   // So, we only write the number of active words.
1644   unsigned NumWords = A.getActiveWords();
1645   const uint64_t *RawData = A.getRawData();
1646   for (unsigned i = 0; i < NumWords; i++)
1647     emitSignedInt64(Vals, RawData[i]);
1648 }
1649 
1650 void ModuleBitcodeWriter::writeDIEnumerator(const DIEnumerator *N,
1651                                             SmallVectorImpl<uint64_t> &Record,
1652                                             unsigned Abbrev) {
1653   const uint64_t IsBigInt = 1 << 2;
1654   Record.push_back(IsBigInt | (N->isUnsigned() << 1) | N->isDistinct());
1655   Record.push_back(N->getValue().getBitWidth());
1656   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1657   emitWideAPInt(Record, N->getValue());
1658 
1659   Stream.EmitRecord(bitc::METADATA_ENUMERATOR, Record, Abbrev);
1660   Record.clear();
1661 }
1662 
1663 void ModuleBitcodeWriter::writeDIBasicType(const DIBasicType *N,
1664                                            SmallVectorImpl<uint64_t> &Record,
1665                                            unsigned Abbrev) {
1666   Record.push_back(N->isDistinct());
1667   Record.push_back(N->getTag());
1668   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1669   Record.push_back(N->getSizeInBits());
1670   Record.push_back(N->getAlignInBits());
1671   Record.push_back(N->getEncoding());
1672   Record.push_back(N->getFlags());
1673 
1674   Stream.EmitRecord(bitc::METADATA_BASIC_TYPE, Record, Abbrev);
1675   Record.clear();
1676 }
1677 
1678 void ModuleBitcodeWriter::writeDIStringType(const DIStringType *N,
1679                                             SmallVectorImpl<uint64_t> &Record,
1680                                             unsigned Abbrev) {
1681   Record.push_back(N->isDistinct());
1682   Record.push_back(N->getTag());
1683   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1684   Record.push_back(VE.getMetadataOrNullID(N->getStringLength()));
1685   Record.push_back(VE.getMetadataOrNullID(N->getStringLengthExp()));
1686   Record.push_back(VE.getMetadataOrNullID(N->getStringLocationExp()));
1687   Record.push_back(N->getSizeInBits());
1688   Record.push_back(N->getAlignInBits());
1689   Record.push_back(N->getEncoding());
1690 
1691   Stream.EmitRecord(bitc::METADATA_STRING_TYPE, Record, Abbrev);
1692   Record.clear();
1693 }
1694 
1695 void ModuleBitcodeWriter::writeDIDerivedType(const DIDerivedType *N,
1696                                              SmallVectorImpl<uint64_t> &Record,
1697                                              unsigned Abbrev) {
1698   Record.push_back(N->isDistinct());
1699   Record.push_back(N->getTag());
1700   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1701   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1702   Record.push_back(N->getLine());
1703   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1704   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1705   Record.push_back(N->getSizeInBits());
1706   Record.push_back(N->getAlignInBits());
1707   Record.push_back(N->getOffsetInBits());
1708   Record.push_back(N->getFlags());
1709   Record.push_back(VE.getMetadataOrNullID(N->getExtraData()));
1710 
1711   // DWARF address space is encoded as N->getDWARFAddressSpace() + 1. 0 means
1712   // that there is no DWARF address space associated with DIDerivedType.
1713   if (const auto &DWARFAddressSpace = N->getDWARFAddressSpace())
1714     Record.push_back(*DWARFAddressSpace + 1);
1715   else
1716     Record.push_back(0);
1717 
1718   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1719 
1720   Stream.EmitRecord(bitc::METADATA_DERIVED_TYPE, Record, Abbrev);
1721   Record.clear();
1722 }
1723 
1724 void ModuleBitcodeWriter::writeDICompositeType(
1725     const DICompositeType *N, SmallVectorImpl<uint64_t> &Record,
1726     unsigned Abbrev) {
1727   const unsigned IsNotUsedInOldTypeRef = 0x2;
1728   Record.push_back(IsNotUsedInOldTypeRef | (unsigned)N->isDistinct());
1729   Record.push_back(N->getTag());
1730   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1731   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1732   Record.push_back(N->getLine());
1733   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1734   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1735   Record.push_back(N->getSizeInBits());
1736   Record.push_back(N->getAlignInBits());
1737   Record.push_back(N->getOffsetInBits());
1738   Record.push_back(N->getFlags());
1739   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1740   Record.push_back(N->getRuntimeLang());
1741   Record.push_back(VE.getMetadataOrNullID(N->getVTableHolder()));
1742   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1743   Record.push_back(VE.getMetadataOrNullID(N->getRawIdentifier()));
1744   Record.push_back(VE.getMetadataOrNullID(N->getDiscriminator()));
1745   Record.push_back(VE.getMetadataOrNullID(N->getRawDataLocation()));
1746   Record.push_back(VE.getMetadataOrNullID(N->getRawAssociated()));
1747   Record.push_back(VE.getMetadataOrNullID(N->getRawAllocated()));
1748   Record.push_back(VE.getMetadataOrNullID(N->getRawRank()));
1749   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1750 
1751   Stream.EmitRecord(bitc::METADATA_COMPOSITE_TYPE, Record, Abbrev);
1752   Record.clear();
1753 }
1754 
1755 void ModuleBitcodeWriter::writeDISubroutineType(
1756     const DISubroutineType *N, SmallVectorImpl<uint64_t> &Record,
1757     unsigned Abbrev) {
1758   const unsigned HasNoOldTypeRefs = 0x2;
1759   Record.push_back(HasNoOldTypeRefs | (unsigned)N->isDistinct());
1760   Record.push_back(N->getFlags());
1761   Record.push_back(VE.getMetadataOrNullID(N->getTypeArray().get()));
1762   Record.push_back(N->getCC());
1763 
1764   Stream.EmitRecord(bitc::METADATA_SUBROUTINE_TYPE, Record, Abbrev);
1765   Record.clear();
1766 }
1767 
1768 void ModuleBitcodeWriter::writeDIFile(const DIFile *N,
1769                                       SmallVectorImpl<uint64_t> &Record,
1770                                       unsigned Abbrev) {
1771   Record.push_back(N->isDistinct());
1772   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
1773   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
1774   if (N->getRawChecksum()) {
1775     Record.push_back(N->getRawChecksum()->Kind);
1776     Record.push_back(VE.getMetadataOrNullID(N->getRawChecksum()->Value));
1777   } else {
1778     // Maintain backwards compatibility with the old internal representation of
1779     // CSK_None in ChecksumKind by writing nulls here when Checksum is None.
1780     Record.push_back(0);
1781     Record.push_back(VE.getMetadataOrNullID(nullptr));
1782   }
1783   auto Source = N->getRawSource();
1784   if (Source)
1785     Record.push_back(VE.getMetadataOrNullID(*Source));
1786 
1787   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
1788   Record.clear();
1789 }
1790 
1791 void ModuleBitcodeWriter::writeDICompileUnit(const DICompileUnit *N,
1792                                              SmallVectorImpl<uint64_t> &Record,
1793                                              unsigned Abbrev) {
1794   assert(N->isDistinct() && "Expected distinct compile units");
1795   Record.push_back(/* IsDistinct */ true);
1796   Record.push_back(N->getSourceLanguage());
1797   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1798   Record.push_back(VE.getMetadataOrNullID(N->getRawProducer()));
1799   Record.push_back(N->isOptimized());
1800   Record.push_back(VE.getMetadataOrNullID(N->getRawFlags()));
1801   Record.push_back(N->getRuntimeVersion());
1802   Record.push_back(VE.getMetadataOrNullID(N->getRawSplitDebugFilename()));
1803   Record.push_back(N->getEmissionKind());
1804   Record.push_back(VE.getMetadataOrNullID(N->getEnumTypes().get()));
1805   Record.push_back(VE.getMetadataOrNullID(N->getRetainedTypes().get()));
1806   Record.push_back(/* subprograms */ 0);
1807   Record.push_back(VE.getMetadataOrNullID(N->getGlobalVariables().get()));
1808   Record.push_back(VE.getMetadataOrNullID(N->getImportedEntities().get()));
1809   Record.push_back(N->getDWOId());
1810   Record.push_back(VE.getMetadataOrNullID(N->getMacros().get()));
1811   Record.push_back(N->getSplitDebugInlining());
1812   Record.push_back(N->getDebugInfoForProfiling());
1813   Record.push_back((unsigned)N->getNameTableKind());
1814   Record.push_back(N->getRangesBaseAddress());
1815   Record.push_back(VE.getMetadataOrNullID(N->getRawSysRoot()));
1816   Record.push_back(VE.getMetadataOrNullID(N->getRawSDK()));
1817 
1818   Stream.EmitRecord(bitc::METADATA_COMPILE_UNIT, Record, Abbrev);
1819   Record.clear();
1820 }
1821 
1822 void ModuleBitcodeWriter::writeDISubprogram(const DISubprogram *N,
1823                                             SmallVectorImpl<uint64_t> &Record,
1824                                             unsigned Abbrev) {
1825   const uint64_t HasUnitFlag = 1 << 1;
1826   const uint64_t HasSPFlagsFlag = 1 << 2;
1827   Record.push_back(uint64_t(N->isDistinct()) | HasUnitFlag | HasSPFlagsFlag);
1828   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1829   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1830   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1831   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1832   Record.push_back(N->getLine());
1833   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1834   Record.push_back(N->getScopeLine());
1835   Record.push_back(VE.getMetadataOrNullID(N->getContainingType()));
1836   Record.push_back(N->getSPFlags());
1837   Record.push_back(N->getVirtualIndex());
1838   Record.push_back(N->getFlags());
1839   Record.push_back(VE.getMetadataOrNullID(N->getRawUnit()));
1840   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1841   Record.push_back(VE.getMetadataOrNullID(N->getDeclaration()));
1842   Record.push_back(VE.getMetadataOrNullID(N->getRetainedNodes().get()));
1843   Record.push_back(N->getThisAdjustment());
1844   Record.push_back(VE.getMetadataOrNullID(N->getThrownTypes().get()));
1845   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1846   Record.push_back(VE.getMetadataOrNullID(N->getRawTargetFuncName()));
1847 
1848   Stream.EmitRecord(bitc::METADATA_SUBPROGRAM, Record, Abbrev);
1849   Record.clear();
1850 }
1851 
1852 void ModuleBitcodeWriter::writeDILexicalBlock(const DILexicalBlock *N,
1853                                               SmallVectorImpl<uint64_t> &Record,
1854                                               unsigned Abbrev) {
1855   Record.push_back(N->isDistinct());
1856   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1857   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1858   Record.push_back(N->getLine());
1859   Record.push_back(N->getColumn());
1860 
1861   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK, Record, Abbrev);
1862   Record.clear();
1863 }
1864 
1865 void ModuleBitcodeWriter::writeDILexicalBlockFile(
1866     const DILexicalBlockFile *N, SmallVectorImpl<uint64_t> &Record,
1867     unsigned Abbrev) {
1868   Record.push_back(N->isDistinct());
1869   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1870   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1871   Record.push_back(N->getDiscriminator());
1872 
1873   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK_FILE, Record, Abbrev);
1874   Record.clear();
1875 }
1876 
1877 void ModuleBitcodeWriter::writeDICommonBlock(const DICommonBlock *N,
1878                                              SmallVectorImpl<uint64_t> &Record,
1879                                              unsigned Abbrev) {
1880   Record.push_back(N->isDistinct());
1881   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1882   Record.push_back(VE.getMetadataOrNullID(N->getDecl()));
1883   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1884   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1885   Record.push_back(N->getLineNo());
1886 
1887   Stream.EmitRecord(bitc::METADATA_COMMON_BLOCK, Record, Abbrev);
1888   Record.clear();
1889 }
1890 
1891 void ModuleBitcodeWriter::writeDINamespace(const DINamespace *N,
1892                                            SmallVectorImpl<uint64_t> &Record,
1893                                            unsigned Abbrev) {
1894   Record.push_back(N->isDistinct() | N->getExportSymbols() << 1);
1895   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1896   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1897 
1898   Stream.EmitRecord(bitc::METADATA_NAMESPACE, Record, Abbrev);
1899   Record.clear();
1900 }
1901 
1902 void ModuleBitcodeWriter::writeDIMacro(const DIMacro *N,
1903                                        SmallVectorImpl<uint64_t> &Record,
1904                                        unsigned Abbrev) {
1905   Record.push_back(N->isDistinct());
1906   Record.push_back(N->getMacinfoType());
1907   Record.push_back(N->getLine());
1908   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1909   Record.push_back(VE.getMetadataOrNullID(N->getRawValue()));
1910 
1911   Stream.EmitRecord(bitc::METADATA_MACRO, Record, Abbrev);
1912   Record.clear();
1913 }
1914 
1915 void ModuleBitcodeWriter::writeDIMacroFile(const DIMacroFile *N,
1916                                            SmallVectorImpl<uint64_t> &Record,
1917                                            unsigned Abbrev) {
1918   Record.push_back(N->isDistinct());
1919   Record.push_back(N->getMacinfoType());
1920   Record.push_back(N->getLine());
1921   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1922   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1923 
1924   Stream.EmitRecord(bitc::METADATA_MACRO_FILE, Record, Abbrev);
1925   Record.clear();
1926 }
1927 
1928 void ModuleBitcodeWriter::writeDIArgList(const DIArgList *N,
1929                                          SmallVectorImpl<uint64_t> &Record,
1930                                          unsigned Abbrev) {
1931   Record.reserve(N->getArgs().size());
1932   for (ValueAsMetadata *MD : N->getArgs())
1933     Record.push_back(VE.getMetadataID(MD));
1934 
1935   Stream.EmitRecord(bitc::METADATA_ARG_LIST, Record, Abbrev);
1936   Record.clear();
1937 }
1938 
1939 void ModuleBitcodeWriter::writeDIModule(const DIModule *N,
1940                                         SmallVectorImpl<uint64_t> &Record,
1941                                         unsigned Abbrev) {
1942   Record.push_back(N->isDistinct());
1943   for (auto &I : N->operands())
1944     Record.push_back(VE.getMetadataOrNullID(I));
1945   Record.push_back(N->getLineNo());
1946   Record.push_back(N->getIsDecl());
1947 
1948   Stream.EmitRecord(bitc::METADATA_MODULE, Record, Abbrev);
1949   Record.clear();
1950 }
1951 
1952 void ModuleBitcodeWriter::writeDITemplateTypeParameter(
1953     const DITemplateTypeParameter *N, SmallVectorImpl<uint64_t> &Record,
1954     unsigned Abbrev) {
1955   Record.push_back(N->isDistinct());
1956   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1957   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1958   Record.push_back(N->isDefault());
1959 
1960   Stream.EmitRecord(bitc::METADATA_TEMPLATE_TYPE, Record, Abbrev);
1961   Record.clear();
1962 }
1963 
1964 void ModuleBitcodeWriter::writeDITemplateValueParameter(
1965     const DITemplateValueParameter *N, SmallVectorImpl<uint64_t> &Record,
1966     unsigned Abbrev) {
1967   Record.push_back(N->isDistinct());
1968   Record.push_back(N->getTag());
1969   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1970   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1971   Record.push_back(N->isDefault());
1972   Record.push_back(VE.getMetadataOrNullID(N->getValue()));
1973 
1974   Stream.EmitRecord(bitc::METADATA_TEMPLATE_VALUE, Record, Abbrev);
1975   Record.clear();
1976 }
1977 
1978 void ModuleBitcodeWriter::writeDIGlobalVariable(
1979     const DIGlobalVariable *N, SmallVectorImpl<uint64_t> &Record,
1980     unsigned Abbrev) {
1981   const uint64_t Version = 2 << 1;
1982   Record.push_back((uint64_t)N->isDistinct() | Version);
1983   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1984   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1985   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1986   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1987   Record.push_back(N->getLine());
1988   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1989   Record.push_back(N->isLocalToUnit());
1990   Record.push_back(N->isDefinition());
1991   Record.push_back(VE.getMetadataOrNullID(N->getStaticDataMemberDeclaration()));
1992   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams()));
1993   Record.push_back(N->getAlignInBits());
1994   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1995 
1996   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR, Record, Abbrev);
1997   Record.clear();
1998 }
1999 
2000 void ModuleBitcodeWriter::writeDILocalVariable(
2001     const DILocalVariable *N, SmallVectorImpl<uint64_t> &Record,
2002     unsigned Abbrev) {
2003   // In order to support all possible bitcode formats in BitcodeReader we need
2004   // to distinguish the following cases:
2005   // 1) Record has no artificial tag (Record[1]),
2006   //   has no obsolete inlinedAt field (Record[9]).
2007   //   In this case Record size will be 8, HasAlignment flag is false.
2008   // 2) Record has artificial tag (Record[1]),
2009   //   has no obsolete inlignedAt field (Record[9]).
2010   //   In this case Record size will be 9, HasAlignment flag is false.
2011   // 3) Record has both artificial tag (Record[1]) and
2012   //   obsolete inlignedAt field (Record[9]).
2013   //   In this case Record size will be 10, HasAlignment flag is false.
2014   // 4) Record has neither artificial tag, nor inlignedAt field, but
2015   //   HasAlignment flag is true and Record[8] contains alignment value.
2016   const uint64_t HasAlignmentFlag = 1 << 1;
2017   Record.push_back((uint64_t)N->isDistinct() | HasAlignmentFlag);
2018   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2019   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2020   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2021   Record.push_back(N->getLine());
2022   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2023   Record.push_back(N->getArg());
2024   Record.push_back(N->getFlags());
2025   Record.push_back(N->getAlignInBits());
2026   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
2027 
2028   Stream.EmitRecord(bitc::METADATA_LOCAL_VAR, Record, Abbrev);
2029   Record.clear();
2030 }
2031 
2032 void ModuleBitcodeWriter::writeDILabel(
2033     const DILabel *N, SmallVectorImpl<uint64_t> &Record,
2034     unsigned Abbrev) {
2035   Record.push_back((uint64_t)N->isDistinct());
2036   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2037   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2038   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2039   Record.push_back(N->getLine());
2040 
2041   Stream.EmitRecord(bitc::METADATA_LABEL, Record, Abbrev);
2042   Record.clear();
2043 }
2044 
2045 void ModuleBitcodeWriter::writeDIExpression(const DIExpression *N,
2046                                             SmallVectorImpl<uint64_t> &Record,
2047                                             unsigned Abbrev) {
2048   Record.reserve(N->getElements().size() + 1);
2049   const uint64_t Version = 3 << 1;
2050   Record.push_back((uint64_t)N->isDistinct() | Version);
2051   Record.append(N->elements_begin(), N->elements_end());
2052 
2053   Stream.EmitRecord(bitc::METADATA_EXPRESSION, Record, Abbrev);
2054   Record.clear();
2055 }
2056 
2057 void ModuleBitcodeWriter::writeDIGlobalVariableExpression(
2058     const DIGlobalVariableExpression *N, SmallVectorImpl<uint64_t> &Record,
2059     unsigned Abbrev) {
2060   Record.push_back(N->isDistinct());
2061   Record.push_back(VE.getMetadataOrNullID(N->getVariable()));
2062   Record.push_back(VE.getMetadataOrNullID(N->getExpression()));
2063 
2064   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR_EXPR, Record, Abbrev);
2065   Record.clear();
2066 }
2067 
2068 void ModuleBitcodeWriter::writeDIObjCProperty(const DIObjCProperty *N,
2069                                               SmallVectorImpl<uint64_t> &Record,
2070                                               unsigned Abbrev) {
2071   Record.push_back(N->isDistinct());
2072   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2073   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2074   Record.push_back(N->getLine());
2075   Record.push_back(VE.getMetadataOrNullID(N->getRawSetterName()));
2076   Record.push_back(VE.getMetadataOrNullID(N->getRawGetterName()));
2077   Record.push_back(N->getAttributes());
2078   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2079 
2080   Stream.EmitRecord(bitc::METADATA_OBJC_PROPERTY, Record, Abbrev);
2081   Record.clear();
2082 }
2083 
2084 void ModuleBitcodeWriter::writeDIImportedEntity(
2085     const DIImportedEntity *N, SmallVectorImpl<uint64_t> &Record,
2086     unsigned Abbrev) {
2087   Record.push_back(N->isDistinct());
2088   Record.push_back(N->getTag());
2089   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2090   Record.push_back(VE.getMetadataOrNullID(N->getEntity()));
2091   Record.push_back(N->getLine());
2092   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2093   Record.push_back(VE.getMetadataOrNullID(N->getRawFile()));
2094   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
2095 
2096   Stream.EmitRecord(bitc::METADATA_IMPORTED_ENTITY, Record, Abbrev);
2097   Record.clear();
2098 }
2099 
2100 unsigned ModuleBitcodeWriter::createNamedMetadataAbbrev() {
2101   auto Abbv = std::make_shared<BitCodeAbbrev>();
2102   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
2103   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2104   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2105   return Stream.EmitAbbrev(std::move(Abbv));
2106 }
2107 
2108 void ModuleBitcodeWriter::writeNamedMetadata(
2109     SmallVectorImpl<uint64_t> &Record) {
2110   if (M.named_metadata_empty())
2111     return;
2112 
2113   unsigned Abbrev = createNamedMetadataAbbrev();
2114   for (const NamedMDNode &NMD : M.named_metadata()) {
2115     // Write name.
2116     StringRef Str = NMD.getName();
2117     Record.append(Str.bytes_begin(), Str.bytes_end());
2118     Stream.EmitRecord(bitc::METADATA_NAME, Record, Abbrev);
2119     Record.clear();
2120 
2121     // Write named metadata operands.
2122     for (const MDNode *N : NMD.operands())
2123       Record.push_back(VE.getMetadataID(N));
2124     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
2125     Record.clear();
2126   }
2127 }
2128 
2129 unsigned ModuleBitcodeWriter::createMetadataStringsAbbrev() {
2130   auto Abbv = std::make_shared<BitCodeAbbrev>();
2131   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRINGS));
2132   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // # of strings
2133   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // offset to chars
2134   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
2135   return Stream.EmitAbbrev(std::move(Abbv));
2136 }
2137 
2138 /// Write out a record for MDString.
2139 ///
2140 /// All the metadata strings in a metadata block are emitted in a single
2141 /// record.  The sizes and strings themselves are shoved into a blob.
2142 void ModuleBitcodeWriter::writeMetadataStrings(
2143     ArrayRef<const Metadata *> Strings, SmallVectorImpl<uint64_t> &Record) {
2144   if (Strings.empty())
2145     return;
2146 
2147   // Start the record with the number of strings.
2148   Record.push_back(bitc::METADATA_STRINGS);
2149   Record.push_back(Strings.size());
2150 
2151   // Emit the sizes of the strings in the blob.
2152   SmallString<256> Blob;
2153   {
2154     BitstreamWriter W(Blob);
2155     for (const Metadata *MD : Strings)
2156       W.EmitVBR(cast<MDString>(MD)->getLength(), 6);
2157     W.FlushToWord();
2158   }
2159 
2160   // Add the offset to the strings to the record.
2161   Record.push_back(Blob.size());
2162 
2163   // Add the strings to the blob.
2164   for (const Metadata *MD : Strings)
2165     Blob.append(cast<MDString>(MD)->getString());
2166 
2167   // Emit the final record.
2168   Stream.EmitRecordWithBlob(createMetadataStringsAbbrev(), Record, Blob);
2169   Record.clear();
2170 }
2171 
2172 // Generates an enum to use as an index in the Abbrev array of Metadata record.
2173 enum MetadataAbbrev : unsigned {
2174 #define HANDLE_MDNODE_LEAF(CLASS) CLASS##AbbrevID,
2175 #include "llvm/IR/Metadata.def"
2176   LastPlusOne
2177 };
2178 
2179 void ModuleBitcodeWriter::writeMetadataRecords(
2180     ArrayRef<const Metadata *> MDs, SmallVectorImpl<uint64_t> &Record,
2181     std::vector<unsigned> *MDAbbrevs, std::vector<uint64_t> *IndexPos) {
2182   if (MDs.empty())
2183     return;
2184 
2185   // Initialize MDNode abbreviations.
2186 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
2187 #include "llvm/IR/Metadata.def"
2188 
2189   for (const Metadata *MD : MDs) {
2190     if (IndexPos)
2191       IndexPos->push_back(Stream.GetCurrentBitNo());
2192     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
2193       assert(N->isResolved() && "Expected forward references to be resolved");
2194 
2195       switch (N->getMetadataID()) {
2196       default:
2197         llvm_unreachable("Invalid MDNode subclass");
2198 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
2199   case Metadata::CLASS##Kind:                                                  \
2200     if (MDAbbrevs)                                                             \
2201       write##CLASS(cast<CLASS>(N), Record,                                     \
2202                    (*MDAbbrevs)[MetadataAbbrev::CLASS##AbbrevID]);             \
2203     else                                                                       \
2204       write##CLASS(cast<CLASS>(N), Record, CLASS##Abbrev);                     \
2205     continue;
2206 #include "llvm/IR/Metadata.def"
2207       }
2208     }
2209     writeValueAsMetadata(cast<ValueAsMetadata>(MD), Record);
2210   }
2211 }
2212 
2213 void ModuleBitcodeWriter::writeModuleMetadata() {
2214   if (!VE.hasMDs() && M.named_metadata_empty())
2215     return;
2216 
2217   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 4);
2218   SmallVector<uint64_t, 64> Record;
2219 
2220   // Emit all abbrevs upfront, so that the reader can jump in the middle of the
2221   // block and load any metadata.
2222   std::vector<unsigned> MDAbbrevs;
2223 
2224   MDAbbrevs.resize(MetadataAbbrev::LastPlusOne);
2225   MDAbbrevs[MetadataAbbrev::DILocationAbbrevID] = createDILocationAbbrev();
2226   MDAbbrevs[MetadataAbbrev::GenericDINodeAbbrevID] =
2227       createGenericDINodeAbbrev();
2228 
2229   auto Abbv = std::make_shared<BitCodeAbbrev>();
2230   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX_OFFSET));
2231   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2232   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2233   unsigned OffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2234 
2235   Abbv = std::make_shared<BitCodeAbbrev>();
2236   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX));
2237   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2238   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2239   unsigned IndexAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2240 
2241   // Emit MDStrings together upfront.
2242   writeMetadataStrings(VE.getMDStrings(), Record);
2243 
2244   // We only emit an index for the metadata record if we have more than a given
2245   // (naive) threshold of metadatas, otherwise it is not worth it.
2246   if (VE.getNonMDStrings().size() > IndexThreshold) {
2247     // Write a placeholder value in for the offset of the metadata index,
2248     // which is written after the records, so that it can include
2249     // the offset of each entry. The placeholder offset will be
2250     // updated after all records are emitted.
2251     uint64_t Vals[] = {0, 0};
2252     Stream.EmitRecord(bitc::METADATA_INDEX_OFFSET, Vals, OffsetAbbrev);
2253   }
2254 
2255   // Compute and save the bit offset to the current position, which will be
2256   // patched when we emit the index later. We can simply subtract the 64-bit
2257   // fixed size from the current bit number to get the location to backpatch.
2258   uint64_t IndexOffsetRecordBitPos = Stream.GetCurrentBitNo();
2259 
2260   // This index will contain the bitpos for each individual record.
2261   std::vector<uint64_t> IndexPos;
2262   IndexPos.reserve(VE.getNonMDStrings().size());
2263 
2264   // Write all the records
2265   writeMetadataRecords(VE.getNonMDStrings(), Record, &MDAbbrevs, &IndexPos);
2266 
2267   if (VE.getNonMDStrings().size() > IndexThreshold) {
2268     // Now that we have emitted all the records we will emit the index. But
2269     // first
2270     // backpatch the forward reference so that the reader can skip the records
2271     // efficiently.
2272     Stream.BackpatchWord64(IndexOffsetRecordBitPos - 64,
2273                            Stream.GetCurrentBitNo() - IndexOffsetRecordBitPos);
2274 
2275     // Delta encode the index.
2276     uint64_t PreviousValue = IndexOffsetRecordBitPos;
2277     for (auto &Elt : IndexPos) {
2278       auto EltDelta = Elt - PreviousValue;
2279       PreviousValue = Elt;
2280       Elt = EltDelta;
2281     }
2282     // Emit the index record.
2283     Stream.EmitRecord(bitc::METADATA_INDEX, IndexPos, IndexAbbrev);
2284     IndexPos.clear();
2285   }
2286 
2287   // Write the named metadata now.
2288   writeNamedMetadata(Record);
2289 
2290   auto AddDeclAttachedMetadata = [&](const GlobalObject &GO) {
2291     SmallVector<uint64_t, 4> Record;
2292     Record.push_back(VE.getValueID(&GO));
2293     pushGlobalMetadataAttachment(Record, GO);
2294     Stream.EmitRecord(bitc::METADATA_GLOBAL_DECL_ATTACHMENT, Record);
2295   };
2296   for (const Function &F : M)
2297     if (F.isDeclaration() && F.hasMetadata())
2298       AddDeclAttachedMetadata(F);
2299   // FIXME: Only store metadata for declarations here, and move data for global
2300   // variable definitions to a separate block (PR28134).
2301   for (const GlobalVariable &GV : M.globals())
2302     if (GV.hasMetadata())
2303       AddDeclAttachedMetadata(GV);
2304 
2305   Stream.ExitBlock();
2306 }
2307 
2308 void ModuleBitcodeWriter::writeFunctionMetadata(const Function &F) {
2309   if (!VE.hasMDs())
2310     return;
2311 
2312   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
2313   SmallVector<uint64_t, 64> Record;
2314   writeMetadataStrings(VE.getMDStrings(), Record);
2315   writeMetadataRecords(VE.getNonMDStrings(), Record);
2316   Stream.ExitBlock();
2317 }
2318 
2319 void ModuleBitcodeWriter::pushGlobalMetadataAttachment(
2320     SmallVectorImpl<uint64_t> &Record, const GlobalObject &GO) {
2321   // [n x [id, mdnode]]
2322   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2323   GO.getAllMetadata(MDs);
2324   for (const auto &I : MDs) {
2325     Record.push_back(I.first);
2326     Record.push_back(VE.getMetadataID(I.second));
2327   }
2328 }
2329 
2330 void ModuleBitcodeWriter::writeFunctionMetadataAttachment(const Function &F) {
2331   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
2332 
2333   SmallVector<uint64_t, 64> Record;
2334 
2335   if (F.hasMetadata()) {
2336     pushGlobalMetadataAttachment(Record, F);
2337     Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2338     Record.clear();
2339   }
2340 
2341   // Write metadata attachments
2342   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
2343   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2344   for (const BasicBlock &BB : F)
2345     for (const Instruction &I : BB) {
2346       MDs.clear();
2347       I.getAllMetadataOtherThanDebugLoc(MDs);
2348 
2349       // If no metadata, ignore instruction.
2350       if (MDs.empty()) continue;
2351 
2352       Record.push_back(VE.getInstructionID(&I));
2353 
2354       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
2355         Record.push_back(MDs[i].first);
2356         Record.push_back(VE.getMetadataID(MDs[i].second));
2357       }
2358       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2359       Record.clear();
2360     }
2361 
2362   Stream.ExitBlock();
2363 }
2364 
2365 void ModuleBitcodeWriter::writeModuleMetadataKinds() {
2366   SmallVector<uint64_t, 64> Record;
2367 
2368   // Write metadata kinds
2369   // METADATA_KIND - [n x [id, name]]
2370   SmallVector<StringRef, 8> Names;
2371   M.getMDKindNames(Names);
2372 
2373   if (Names.empty()) return;
2374 
2375   Stream.EnterSubblock(bitc::METADATA_KIND_BLOCK_ID, 3);
2376 
2377   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
2378     Record.push_back(MDKindID);
2379     StringRef KName = Names[MDKindID];
2380     Record.append(KName.begin(), KName.end());
2381 
2382     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
2383     Record.clear();
2384   }
2385 
2386   Stream.ExitBlock();
2387 }
2388 
2389 void ModuleBitcodeWriter::writeOperandBundleTags() {
2390   // Write metadata kinds
2391   //
2392   // OPERAND_BUNDLE_TAGS_BLOCK_ID : N x OPERAND_BUNDLE_TAG
2393   //
2394   // OPERAND_BUNDLE_TAG - [strchr x N]
2395 
2396   SmallVector<StringRef, 8> Tags;
2397   M.getOperandBundleTags(Tags);
2398 
2399   if (Tags.empty())
2400     return;
2401 
2402   Stream.EnterSubblock(bitc::OPERAND_BUNDLE_TAGS_BLOCK_ID, 3);
2403 
2404   SmallVector<uint64_t, 64> Record;
2405 
2406   for (auto Tag : Tags) {
2407     Record.append(Tag.begin(), Tag.end());
2408 
2409     Stream.EmitRecord(bitc::OPERAND_BUNDLE_TAG, Record, 0);
2410     Record.clear();
2411   }
2412 
2413   Stream.ExitBlock();
2414 }
2415 
2416 void ModuleBitcodeWriter::writeSyncScopeNames() {
2417   SmallVector<StringRef, 8> SSNs;
2418   M.getContext().getSyncScopeNames(SSNs);
2419   if (SSNs.empty())
2420     return;
2421 
2422   Stream.EnterSubblock(bitc::SYNC_SCOPE_NAMES_BLOCK_ID, 2);
2423 
2424   SmallVector<uint64_t, 64> Record;
2425   for (auto SSN : SSNs) {
2426     Record.append(SSN.begin(), SSN.end());
2427     Stream.EmitRecord(bitc::SYNC_SCOPE_NAME, Record, 0);
2428     Record.clear();
2429   }
2430 
2431   Stream.ExitBlock();
2432 }
2433 
2434 void ModuleBitcodeWriter::writeConstants(unsigned FirstVal, unsigned LastVal,
2435                                          bool isGlobal) {
2436   if (FirstVal == LastVal) return;
2437 
2438   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
2439 
2440   unsigned AggregateAbbrev = 0;
2441   unsigned String8Abbrev = 0;
2442   unsigned CString7Abbrev = 0;
2443   unsigned CString6Abbrev = 0;
2444   // If this is a constant pool for the module, emit module-specific abbrevs.
2445   if (isGlobal) {
2446     // Abbrev for CST_CODE_AGGREGATE.
2447     auto Abbv = std::make_shared<BitCodeAbbrev>();
2448     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
2449     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2450     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
2451     AggregateAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2452 
2453     // Abbrev for CST_CODE_STRING.
2454     Abbv = std::make_shared<BitCodeAbbrev>();
2455     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
2456     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2457     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2458     String8Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2459     // Abbrev for CST_CODE_CSTRING.
2460     Abbv = std::make_shared<BitCodeAbbrev>();
2461     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2462     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2463     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2464     CString7Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2465     // Abbrev for CST_CODE_CSTRING.
2466     Abbv = std::make_shared<BitCodeAbbrev>();
2467     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2468     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2469     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2470     CString6Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2471   }
2472 
2473   SmallVector<uint64_t, 64> Record;
2474 
2475   const ValueEnumerator::ValueList &Vals = VE.getValues();
2476   Type *LastTy = nullptr;
2477   for (unsigned i = FirstVal; i != LastVal; ++i) {
2478     const Value *V = Vals[i].first;
2479     // If we need to switch types, do so now.
2480     if (V->getType() != LastTy) {
2481       LastTy = V->getType();
2482       Record.push_back(VE.getTypeID(LastTy));
2483       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
2484                         CONSTANTS_SETTYPE_ABBREV);
2485       Record.clear();
2486     }
2487 
2488     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
2489       Record.push_back(VE.getTypeID(IA->getFunctionType()));
2490       Record.push_back(
2491           unsigned(IA->hasSideEffects()) | unsigned(IA->isAlignStack()) << 1 |
2492           unsigned(IA->getDialect() & 1) << 2 | unsigned(IA->canThrow()) << 3);
2493 
2494       // Add the asm string.
2495       const std::string &AsmStr = IA->getAsmString();
2496       Record.push_back(AsmStr.size());
2497       Record.append(AsmStr.begin(), AsmStr.end());
2498 
2499       // Add the constraint string.
2500       const std::string &ConstraintStr = IA->getConstraintString();
2501       Record.push_back(ConstraintStr.size());
2502       Record.append(ConstraintStr.begin(), ConstraintStr.end());
2503       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
2504       Record.clear();
2505       continue;
2506     }
2507     const Constant *C = cast<Constant>(V);
2508     unsigned Code = -1U;
2509     unsigned AbbrevToUse = 0;
2510     if (C->isNullValue()) {
2511       Code = bitc::CST_CODE_NULL;
2512     } else if (isa<PoisonValue>(C)) {
2513       Code = bitc::CST_CODE_POISON;
2514     } else if (isa<UndefValue>(C)) {
2515       Code = bitc::CST_CODE_UNDEF;
2516     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
2517       if (IV->getBitWidth() <= 64) {
2518         uint64_t V = IV->getSExtValue();
2519         emitSignedInt64(Record, V);
2520         Code = bitc::CST_CODE_INTEGER;
2521         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
2522       } else {                             // Wide integers, > 64 bits in size.
2523         emitWideAPInt(Record, IV->getValue());
2524         Code = bitc::CST_CODE_WIDE_INTEGER;
2525       }
2526     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
2527       Code = bitc::CST_CODE_FLOAT;
2528       Type *Ty = CFP->getType();
2529       if (Ty->isHalfTy() || Ty->isBFloatTy() || Ty->isFloatTy() ||
2530           Ty->isDoubleTy()) {
2531         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
2532       } else if (Ty->isX86_FP80Ty()) {
2533         // api needed to prevent premature destruction
2534         // bits are not in the same order as a normal i80 APInt, compensate.
2535         APInt api = CFP->getValueAPF().bitcastToAPInt();
2536         const uint64_t *p = api.getRawData();
2537         Record.push_back((p[1] << 48) | (p[0] >> 16));
2538         Record.push_back(p[0] & 0xffffLL);
2539       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
2540         APInt api = CFP->getValueAPF().bitcastToAPInt();
2541         const uint64_t *p = api.getRawData();
2542         Record.push_back(p[0]);
2543         Record.push_back(p[1]);
2544       } else {
2545         assert(0 && "Unknown FP type!");
2546       }
2547     } else if (isa<ConstantDataSequential>(C) &&
2548                cast<ConstantDataSequential>(C)->isString()) {
2549       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
2550       // Emit constant strings specially.
2551       unsigned NumElts = Str->getNumElements();
2552       // If this is a null-terminated string, use the denser CSTRING encoding.
2553       if (Str->isCString()) {
2554         Code = bitc::CST_CODE_CSTRING;
2555         --NumElts;  // Don't encode the null, which isn't allowed by char6.
2556       } else {
2557         Code = bitc::CST_CODE_STRING;
2558         AbbrevToUse = String8Abbrev;
2559       }
2560       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
2561       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
2562       for (unsigned i = 0; i != NumElts; ++i) {
2563         unsigned char V = Str->getElementAsInteger(i);
2564         Record.push_back(V);
2565         isCStr7 &= (V & 128) == 0;
2566         if (isCStrChar6)
2567           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
2568       }
2569 
2570       if (isCStrChar6)
2571         AbbrevToUse = CString6Abbrev;
2572       else if (isCStr7)
2573         AbbrevToUse = CString7Abbrev;
2574     } else if (const ConstantDataSequential *CDS =
2575                   dyn_cast<ConstantDataSequential>(C)) {
2576       Code = bitc::CST_CODE_DATA;
2577       Type *EltTy = CDS->getElementType();
2578       if (isa<IntegerType>(EltTy)) {
2579         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2580           Record.push_back(CDS->getElementAsInteger(i));
2581       } else {
2582         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2583           Record.push_back(
2584               CDS->getElementAsAPFloat(i).bitcastToAPInt().getLimitedValue());
2585       }
2586     } else if (isa<ConstantAggregate>(C)) {
2587       Code = bitc::CST_CODE_AGGREGATE;
2588       for (const Value *Op : C->operands())
2589         Record.push_back(VE.getValueID(Op));
2590       AbbrevToUse = AggregateAbbrev;
2591     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
2592       switch (CE->getOpcode()) {
2593       default:
2594         if (Instruction::isCast(CE->getOpcode())) {
2595           Code = bitc::CST_CODE_CE_CAST;
2596           Record.push_back(getEncodedCastOpcode(CE->getOpcode()));
2597           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2598           Record.push_back(VE.getValueID(C->getOperand(0)));
2599           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
2600         } else {
2601           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
2602           Code = bitc::CST_CODE_CE_BINOP;
2603           Record.push_back(getEncodedBinaryOpcode(CE->getOpcode()));
2604           Record.push_back(VE.getValueID(C->getOperand(0)));
2605           Record.push_back(VE.getValueID(C->getOperand(1)));
2606           uint64_t Flags = getOptimizationFlags(CE);
2607           if (Flags != 0)
2608             Record.push_back(Flags);
2609         }
2610         break;
2611       case Instruction::FNeg: {
2612         assert(CE->getNumOperands() == 1 && "Unknown constant expr!");
2613         Code = bitc::CST_CODE_CE_UNOP;
2614         Record.push_back(getEncodedUnaryOpcode(CE->getOpcode()));
2615         Record.push_back(VE.getValueID(C->getOperand(0)));
2616         uint64_t Flags = getOptimizationFlags(CE);
2617         if (Flags != 0)
2618           Record.push_back(Flags);
2619         break;
2620       }
2621       case Instruction::GetElementPtr: {
2622         Code = bitc::CST_CODE_CE_GEP;
2623         const auto *GO = cast<GEPOperator>(C);
2624         Record.push_back(VE.getTypeID(GO->getSourceElementType()));
2625         if (Optional<unsigned> Idx = GO->getInRangeIndex()) {
2626           Code = bitc::CST_CODE_CE_GEP_WITH_INRANGE_INDEX;
2627           Record.push_back((*Idx << 1) | GO->isInBounds());
2628         } else if (GO->isInBounds())
2629           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
2630         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
2631           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
2632           Record.push_back(VE.getValueID(C->getOperand(i)));
2633         }
2634         break;
2635       }
2636       case Instruction::Select:
2637         Code = bitc::CST_CODE_CE_SELECT;
2638         Record.push_back(VE.getValueID(C->getOperand(0)));
2639         Record.push_back(VE.getValueID(C->getOperand(1)));
2640         Record.push_back(VE.getValueID(C->getOperand(2)));
2641         break;
2642       case Instruction::ExtractElement:
2643         Code = bitc::CST_CODE_CE_EXTRACTELT;
2644         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2645         Record.push_back(VE.getValueID(C->getOperand(0)));
2646         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
2647         Record.push_back(VE.getValueID(C->getOperand(1)));
2648         break;
2649       case Instruction::InsertElement:
2650         Code = bitc::CST_CODE_CE_INSERTELT;
2651         Record.push_back(VE.getValueID(C->getOperand(0)));
2652         Record.push_back(VE.getValueID(C->getOperand(1)));
2653         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
2654         Record.push_back(VE.getValueID(C->getOperand(2)));
2655         break;
2656       case Instruction::ShuffleVector:
2657         // If the return type and argument types are the same, this is a
2658         // standard shufflevector instruction.  If the types are different,
2659         // then the shuffle is widening or truncating the input vectors, and
2660         // the argument type must also be encoded.
2661         if (C->getType() == C->getOperand(0)->getType()) {
2662           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
2663         } else {
2664           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
2665           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2666         }
2667         Record.push_back(VE.getValueID(C->getOperand(0)));
2668         Record.push_back(VE.getValueID(C->getOperand(1)));
2669         Record.push_back(VE.getValueID(CE->getShuffleMaskForBitcode()));
2670         break;
2671       case Instruction::ICmp:
2672       case Instruction::FCmp:
2673         Code = bitc::CST_CODE_CE_CMP;
2674         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2675         Record.push_back(VE.getValueID(C->getOperand(0)));
2676         Record.push_back(VE.getValueID(C->getOperand(1)));
2677         Record.push_back(CE->getPredicate());
2678         break;
2679       }
2680     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
2681       Code = bitc::CST_CODE_BLOCKADDRESS;
2682       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
2683       Record.push_back(VE.getValueID(BA->getFunction()));
2684       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
2685     } else if (const auto *Equiv = dyn_cast<DSOLocalEquivalent>(C)) {
2686       Code = bitc::CST_CODE_DSO_LOCAL_EQUIVALENT;
2687       Record.push_back(VE.getTypeID(Equiv->getGlobalValue()->getType()));
2688       Record.push_back(VE.getValueID(Equiv->getGlobalValue()));
2689     } else if (const auto *NC = dyn_cast<NoCFIValue>(C)) {
2690       Code = bitc::CST_CODE_NO_CFI_VALUE;
2691       Record.push_back(VE.getTypeID(NC->getGlobalValue()->getType()));
2692       Record.push_back(VE.getValueID(NC->getGlobalValue()));
2693     } else {
2694 #ifndef NDEBUG
2695       C->dump();
2696 #endif
2697       llvm_unreachable("Unknown constant!");
2698     }
2699     Stream.EmitRecord(Code, Record, AbbrevToUse);
2700     Record.clear();
2701   }
2702 
2703   Stream.ExitBlock();
2704 }
2705 
2706 void ModuleBitcodeWriter::writeModuleConstants() {
2707   const ValueEnumerator::ValueList &Vals = VE.getValues();
2708 
2709   // Find the first constant to emit, which is the first non-globalvalue value.
2710   // We know globalvalues have been emitted by WriteModuleInfo.
2711   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
2712     if (!isa<GlobalValue>(Vals[i].first)) {
2713       writeConstants(i, Vals.size(), true);
2714       return;
2715     }
2716   }
2717 }
2718 
2719 /// pushValueAndType - The file has to encode both the value and type id for
2720 /// many values, because we need to know what type to create for forward
2721 /// references.  However, most operands are not forward references, so this type
2722 /// field is not needed.
2723 ///
2724 /// This function adds V's value ID to Vals.  If the value ID is higher than the
2725 /// instruction ID, then it is a forward reference, and it also includes the
2726 /// type ID.  The value ID that is written is encoded relative to the InstID.
2727 bool ModuleBitcodeWriter::pushValueAndType(const Value *V, unsigned InstID,
2728                                            SmallVectorImpl<unsigned> &Vals) {
2729   unsigned ValID = VE.getValueID(V);
2730   // Make encoding relative to the InstID.
2731   Vals.push_back(InstID - ValID);
2732   if (ValID >= InstID) {
2733     Vals.push_back(VE.getTypeID(V->getType()));
2734     return true;
2735   }
2736   return false;
2737 }
2738 
2739 void ModuleBitcodeWriter::writeOperandBundles(const CallBase &CS,
2740                                               unsigned InstID) {
2741   SmallVector<unsigned, 64> Record;
2742   LLVMContext &C = CS.getContext();
2743 
2744   for (unsigned i = 0, e = CS.getNumOperandBundles(); i != e; ++i) {
2745     const auto &Bundle = CS.getOperandBundleAt(i);
2746     Record.push_back(C.getOperandBundleTagID(Bundle.getTagName()));
2747 
2748     for (auto &Input : Bundle.Inputs)
2749       pushValueAndType(Input, InstID, Record);
2750 
2751     Stream.EmitRecord(bitc::FUNC_CODE_OPERAND_BUNDLE, Record);
2752     Record.clear();
2753   }
2754 }
2755 
2756 /// pushValue - Like pushValueAndType, but where the type of the value is
2757 /// omitted (perhaps it was already encoded in an earlier operand).
2758 void ModuleBitcodeWriter::pushValue(const Value *V, unsigned InstID,
2759                                     SmallVectorImpl<unsigned> &Vals) {
2760   unsigned ValID = VE.getValueID(V);
2761   Vals.push_back(InstID - ValID);
2762 }
2763 
2764 void ModuleBitcodeWriter::pushValueSigned(const Value *V, unsigned InstID,
2765                                           SmallVectorImpl<uint64_t> &Vals) {
2766   unsigned ValID = VE.getValueID(V);
2767   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
2768   emitSignedInt64(Vals, diff);
2769 }
2770 
2771 /// WriteInstruction - Emit an instruction to the specified stream.
2772 void ModuleBitcodeWriter::writeInstruction(const Instruction &I,
2773                                            unsigned InstID,
2774                                            SmallVectorImpl<unsigned> &Vals) {
2775   unsigned Code = 0;
2776   unsigned AbbrevToUse = 0;
2777   VE.setInstructionID(&I);
2778   switch (I.getOpcode()) {
2779   default:
2780     if (Instruction::isCast(I.getOpcode())) {
2781       Code = bitc::FUNC_CODE_INST_CAST;
2782       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2783         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
2784       Vals.push_back(VE.getTypeID(I.getType()));
2785       Vals.push_back(getEncodedCastOpcode(I.getOpcode()));
2786     } else {
2787       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
2788       Code = bitc::FUNC_CODE_INST_BINOP;
2789       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2790         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
2791       pushValue(I.getOperand(1), InstID, Vals);
2792       Vals.push_back(getEncodedBinaryOpcode(I.getOpcode()));
2793       uint64_t Flags = getOptimizationFlags(&I);
2794       if (Flags != 0) {
2795         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
2796           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
2797         Vals.push_back(Flags);
2798       }
2799     }
2800     break;
2801   case Instruction::FNeg: {
2802     Code = bitc::FUNC_CODE_INST_UNOP;
2803     if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2804       AbbrevToUse = FUNCTION_INST_UNOP_ABBREV;
2805     Vals.push_back(getEncodedUnaryOpcode(I.getOpcode()));
2806     uint64_t Flags = getOptimizationFlags(&I);
2807     if (Flags != 0) {
2808       if (AbbrevToUse == FUNCTION_INST_UNOP_ABBREV)
2809         AbbrevToUse = FUNCTION_INST_UNOP_FLAGS_ABBREV;
2810       Vals.push_back(Flags);
2811     }
2812     break;
2813   }
2814   case Instruction::GetElementPtr: {
2815     Code = bitc::FUNC_CODE_INST_GEP;
2816     AbbrevToUse = FUNCTION_INST_GEP_ABBREV;
2817     auto &GEPInst = cast<GetElementPtrInst>(I);
2818     Vals.push_back(GEPInst.isInBounds());
2819     Vals.push_back(VE.getTypeID(GEPInst.getSourceElementType()));
2820     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
2821       pushValueAndType(I.getOperand(i), InstID, Vals);
2822     break;
2823   }
2824   case Instruction::ExtractValue: {
2825     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
2826     pushValueAndType(I.getOperand(0), InstID, Vals);
2827     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
2828     Vals.append(EVI->idx_begin(), EVI->idx_end());
2829     break;
2830   }
2831   case Instruction::InsertValue: {
2832     Code = bitc::FUNC_CODE_INST_INSERTVAL;
2833     pushValueAndType(I.getOperand(0), InstID, Vals);
2834     pushValueAndType(I.getOperand(1), InstID, Vals);
2835     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
2836     Vals.append(IVI->idx_begin(), IVI->idx_end());
2837     break;
2838   }
2839   case Instruction::Select: {
2840     Code = bitc::FUNC_CODE_INST_VSELECT;
2841     pushValueAndType(I.getOperand(1), InstID, Vals);
2842     pushValue(I.getOperand(2), InstID, Vals);
2843     pushValueAndType(I.getOperand(0), InstID, Vals);
2844     uint64_t Flags = getOptimizationFlags(&I);
2845     if (Flags != 0)
2846       Vals.push_back(Flags);
2847     break;
2848   }
2849   case Instruction::ExtractElement:
2850     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
2851     pushValueAndType(I.getOperand(0), InstID, Vals);
2852     pushValueAndType(I.getOperand(1), InstID, Vals);
2853     break;
2854   case Instruction::InsertElement:
2855     Code = bitc::FUNC_CODE_INST_INSERTELT;
2856     pushValueAndType(I.getOperand(0), InstID, Vals);
2857     pushValue(I.getOperand(1), InstID, Vals);
2858     pushValueAndType(I.getOperand(2), InstID, Vals);
2859     break;
2860   case Instruction::ShuffleVector:
2861     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
2862     pushValueAndType(I.getOperand(0), InstID, Vals);
2863     pushValue(I.getOperand(1), InstID, Vals);
2864     pushValue(cast<ShuffleVectorInst>(I).getShuffleMaskForBitcode(), InstID,
2865               Vals);
2866     break;
2867   case Instruction::ICmp:
2868   case Instruction::FCmp: {
2869     // compare returning Int1Ty or vector of Int1Ty
2870     Code = bitc::FUNC_CODE_INST_CMP2;
2871     pushValueAndType(I.getOperand(0), InstID, Vals);
2872     pushValue(I.getOperand(1), InstID, Vals);
2873     Vals.push_back(cast<CmpInst>(I).getPredicate());
2874     uint64_t Flags = getOptimizationFlags(&I);
2875     if (Flags != 0)
2876       Vals.push_back(Flags);
2877     break;
2878   }
2879 
2880   case Instruction::Ret:
2881     {
2882       Code = bitc::FUNC_CODE_INST_RET;
2883       unsigned NumOperands = I.getNumOperands();
2884       if (NumOperands == 0)
2885         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
2886       else if (NumOperands == 1) {
2887         if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2888           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
2889       } else {
2890         for (unsigned i = 0, e = NumOperands; i != e; ++i)
2891           pushValueAndType(I.getOperand(i), InstID, Vals);
2892       }
2893     }
2894     break;
2895   case Instruction::Br:
2896     {
2897       Code = bitc::FUNC_CODE_INST_BR;
2898       const BranchInst &II = cast<BranchInst>(I);
2899       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
2900       if (II.isConditional()) {
2901         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
2902         pushValue(II.getCondition(), InstID, Vals);
2903       }
2904     }
2905     break;
2906   case Instruction::Switch:
2907     {
2908       Code = bitc::FUNC_CODE_INST_SWITCH;
2909       const SwitchInst &SI = cast<SwitchInst>(I);
2910       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
2911       pushValue(SI.getCondition(), InstID, Vals);
2912       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
2913       for (auto Case : SI.cases()) {
2914         Vals.push_back(VE.getValueID(Case.getCaseValue()));
2915         Vals.push_back(VE.getValueID(Case.getCaseSuccessor()));
2916       }
2917     }
2918     break;
2919   case Instruction::IndirectBr:
2920     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
2921     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2922     // Encode the address operand as relative, but not the basic blocks.
2923     pushValue(I.getOperand(0), InstID, Vals);
2924     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
2925       Vals.push_back(VE.getValueID(I.getOperand(i)));
2926     break;
2927 
2928   case Instruction::Invoke: {
2929     const InvokeInst *II = cast<InvokeInst>(&I);
2930     const Value *Callee = II->getCalledOperand();
2931     FunctionType *FTy = II->getFunctionType();
2932 
2933     if (II->hasOperandBundles())
2934       writeOperandBundles(*II, InstID);
2935 
2936     Code = bitc::FUNC_CODE_INST_INVOKE;
2937 
2938     Vals.push_back(VE.getAttributeListID(II->getAttributes()));
2939     Vals.push_back(II->getCallingConv() | 1 << 13);
2940     Vals.push_back(VE.getValueID(II->getNormalDest()));
2941     Vals.push_back(VE.getValueID(II->getUnwindDest()));
2942     Vals.push_back(VE.getTypeID(FTy));
2943     pushValueAndType(Callee, InstID, Vals);
2944 
2945     // Emit value #'s for the fixed parameters.
2946     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
2947       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
2948 
2949     // Emit type/value pairs for varargs params.
2950     if (FTy->isVarArg()) {
2951       for (unsigned i = FTy->getNumParams(), e = II->arg_size(); i != e; ++i)
2952         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
2953     }
2954     break;
2955   }
2956   case Instruction::Resume:
2957     Code = bitc::FUNC_CODE_INST_RESUME;
2958     pushValueAndType(I.getOperand(0), InstID, Vals);
2959     break;
2960   case Instruction::CleanupRet: {
2961     Code = bitc::FUNC_CODE_INST_CLEANUPRET;
2962     const auto &CRI = cast<CleanupReturnInst>(I);
2963     pushValue(CRI.getCleanupPad(), InstID, Vals);
2964     if (CRI.hasUnwindDest())
2965       Vals.push_back(VE.getValueID(CRI.getUnwindDest()));
2966     break;
2967   }
2968   case Instruction::CatchRet: {
2969     Code = bitc::FUNC_CODE_INST_CATCHRET;
2970     const auto &CRI = cast<CatchReturnInst>(I);
2971     pushValue(CRI.getCatchPad(), InstID, Vals);
2972     Vals.push_back(VE.getValueID(CRI.getSuccessor()));
2973     break;
2974   }
2975   case Instruction::CleanupPad:
2976   case Instruction::CatchPad: {
2977     const auto &FuncletPad = cast<FuncletPadInst>(I);
2978     Code = isa<CatchPadInst>(FuncletPad) ? bitc::FUNC_CODE_INST_CATCHPAD
2979                                          : bitc::FUNC_CODE_INST_CLEANUPPAD;
2980     pushValue(FuncletPad.getParentPad(), InstID, Vals);
2981 
2982     unsigned NumArgOperands = FuncletPad.arg_size();
2983     Vals.push_back(NumArgOperands);
2984     for (unsigned Op = 0; Op != NumArgOperands; ++Op)
2985       pushValueAndType(FuncletPad.getArgOperand(Op), InstID, Vals);
2986     break;
2987   }
2988   case Instruction::CatchSwitch: {
2989     Code = bitc::FUNC_CODE_INST_CATCHSWITCH;
2990     const auto &CatchSwitch = cast<CatchSwitchInst>(I);
2991 
2992     pushValue(CatchSwitch.getParentPad(), InstID, Vals);
2993 
2994     unsigned NumHandlers = CatchSwitch.getNumHandlers();
2995     Vals.push_back(NumHandlers);
2996     for (const BasicBlock *CatchPadBB : CatchSwitch.handlers())
2997       Vals.push_back(VE.getValueID(CatchPadBB));
2998 
2999     if (CatchSwitch.hasUnwindDest())
3000       Vals.push_back(VE.getValueID(CatchSwitch.getUnwindDest()));
3001     break;
3002   }
3003   case Instruction::CallBr: {
3004     const CallBrInst *CBI = cast<CallBrInst>(&I);
3005     const Value *Callee = CBI->getCalledOperand();
3006     FunctionType *FTy = CBI->getFunctionType();
3007 
3008     if (CBI->hasOperandBundles())
3009       writeOperandBundles(*CBI, InstID);
3010 
3011     Code = bitc::FUNC_CODE_INST_CALLBR;
3012 
3013     Vals.push_back(VE.getAttributeListID(CBI->getAttributes()));
3014 
3015     Vals.push_back(CBI->getCallingConv() << bitc::CALL_CCONV |
3016                    1 << bitc::CALL_EXPLICIT_TYPE);
3017 
3018     Vals.push_back(VE.getValueID(CBI->getDefaultDest()));
3019     Vals.push_back(CBI->getNumIndirectDests());
3020     for (unsigned i = 0, e = CBI->getNumIndirectDests(); i != e; ++i)
3021       Vals.push_back(VE.getValueID(CBI->getIndirectDest(i)));
3022 
3023     Vals.push_back(VE.getTypeID(FTy));
3024     pushValueAndType(Callee, InstID, Vals);
3025 
3026     // Emit value #'s for the fixed parameters.
3027     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
3028       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
3029 
3030     // Emit type/value pairs for varargs params.
3031     if (FTy->isVarArg()) {
3032       for (unsigned i = FTy->getNumParams(), e = CBI->arg_size(); i != e; ++i)
3033         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
3034     }
3035     break;
3036   }
3037   case Instruction::Unreachable:
3038     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
3039     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
3040     break;
3041 
3042   case Instruction::PHI: {
3043     const PHINode &PN = cast<PHINode>(I);
3044     Code = bitc::FUNC_CODE_INST_PHI;
3045     // With the newer instruction encoding, forward references could give
3046     // negative valued IDs.  This is most common for PHIs, so we use
3047     // signed VBRs.
3048     SmallVector<uint64_t, 128> Vals64;
3049     Vals64.push_back(VE.getTypeID(PN.getType()));
3050     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
3051       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64);
3052       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
3053     }
3054 
3055     uint64_t Flags = getOptimizationFlags(&I);
3056     if (Flags != 0)
3057       Vals64.push_back(Flags);
3058 
3059     // Emit a Vals64 vector and exit.
3060     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
3061     Vals64.clear();
3062     return;
3063   }
3064 
3065   case Instruction::LandingPad: {
3066     const LandingPadInst &LP = cast<LandingPadInst>(I);
3067     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
3068     Vals.push_back(VE.getTypeID(LP.getType()));
3069     Vals.push_back(LP.isCleanup());
3070     Vals.push_back(LP.getNumClauses());
3071     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
3072       if (LP.isCatch(I))
3073         Vals.push_back(LandingPadInst::Catch);
3074       else
3075         Vals.push_back(LandingPadInst::Filter);
3076       pushValueAndType(LP.getClause(I), InstID, Vals);
3077     }
3078     break;
3079   }
3080 
3081   case Instruction::Alloca: {
3082     Code = bitc::FUNC_CODE_INST_ALLOCA;
3083     const AllocaInst &AI = cast<AllocaInst>(I);
3084     Vals.push_back(VE.getTypeID(AI.getAllocatedType()));
3085     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
3086     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
3087     using APV = AllocaPackedValues;
3088     unsigned Record = 0;
3089     unsigned EncodedAlign = getEncodedAlign(AI.getAlign());
3090     Bitfield::set<APV::AlignLower>(
3091         Record, EncodedAlign & ((1 << APV::AlignLower::Bits) - 1));
3092     Bitfield::set<APV::AlignUpper>(Record,
3093                                    EncodedAlign >> APV::AlignLower::Bits);
3094     Bitfield::set<APV::UsedWithInAlloca>(Record, AI.isUsedWithInAlloca());
3095     Bitfield::set<APV::ExplicitType>(Record, true);
3096     Bitfield::set<APV::SwiftError>(Record, AI.isSwiftError());
3097     Vals.push_back(Record);
3098 
3099     unsigned AS = AI.getAddressSpace();
3100     if (AS != M.getDataLayout().getAllocaAddrSpace())
3101       Vals.push_back(AS);
3102     break;
3103   }
3104 
3105   case Instruction::Load:
3106     if (cast<LoadInst>(I).isAtomic()) {
3107       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
3108       pushValueAndType(I.getOperand(0), InstID, Vals);
3109     } else {
3110       Code = bitc::FUNC_CODE_INST_LOAD;
3111       if (!pushValueAndType(I.getOperand(0), InstID, Vals)) // ptr
3112         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
3113     }
3114     Vals.push_back(VE.getTypeID(I.getType()));
3115     Vals.push_back(getEncodedAlign(cast<LoadInst>(I).getAlign()));
3116     Vals.push_back(cast<LoadInst>(I).isVolatile());
3117     if (cast<LoadInst>(I).isAtomic()) {
3118       Vals.push_back(getEncodedOrdering(cast<LoadInst>(I).getOrdering()));
3119       Vals.push_back(getEncodedSyncScopeID(cast<LoadInst>(I).getSyncScopeID()));
3120     }
3121     break;
3122   case Instruction::Store:
3123     if (cast<StoreInst>(I).isAtomic())
3124       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
3125     else
3126       Code = bitc::FUNC_CODE_INST_STORE;
3127     pushValueAndType(I.getOperand(1), InstID, Vals); // ptrty + ptr
3128     pushValueAndType(I.getOperand(0), InstID, Vals); // valty + val
3129     Vals.push_back(getEncodedAlign(cast<StoreInst>(I).getAlign()));
3130     Vals.push_back(cast<StoreInst>(I).isVolatile());
3131     if (cast<StoreInst>(I).isAtomic()) {
3132       Vals.push_back(getEncodedOrdering(cast<StoreInst>(I).getOrdering()));
3133       Vals.push_back(
3134           getEncodedSyncScopeID(cast<StoreInst>(I).getSyncScopeID()));
3135     }
3136     break;
3137   case Instruction::AtomicCmpXchg:
3138     Code = bitc::FUNC_CODE_INST_CMPXCHG;
3139     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
3140     pushValueAndType(I.getOperand(1), InstID, Vals); // cmp.
3141     pushValue(I.getOperand(2), InstID, Vals);        // newval.
3142     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
3143     Vals.push_back(
3144         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
3145     Vals.push_back(
3146         getEncodedSyncScopeID(cast<AtomicCmpXchgInst>(I).getSyncScopeID()));
3147     Vals.push_back(
3148         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
3149     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
3150     Vals.push_back(getEncodedAlign(cast<AtomicCmpXchgInst>(I).getAlign()));
3151     break;
3152   case Instruction::AtomicRMW:
3153     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
3154     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
3155     pushValueAndType(I.getOperand(1), InstID, Vals); // valty + val
3156     Vals.push_back(
3157         getEncodedRMWOperation(cast<AtomicRMWInst>(I).getOperation()));
3158     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
3159     Vals.push_back(getEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
3160     Vals.push_back(
3161         getEncodedSyncScopeID(cast<AtomicRMWInst>(I).getSyncScopeID()));
3162     Vals.push_back(getEncodedAlign(cast<AtomicRMWInst>(I).getAlign()));
3163     break;
3164   case Instruction::Fence:
3165     Code = bitc::FUNC_CODE_INST_FENCE;
3166     Vals.push_back(getEncodedOrdering(cast<FenceInst>(I).getOrdering()));
3167     Vals.push_back(getEncodedSyncScopeID(cast<FenceInst>(I).getSyncScopeID()));
3168     break;
3169   case Instruction::Call: {
3170     const CallInst &CI = cast<CallInst>(I);
3171     FunctionType *FTy = CI.getFunctionType();
3172 
3173     if (CI.hasOperandBundles())
3174       writeOperandBundles(CI, InstID);
3175 
3176     Code = bitc::FUNC_CODE_INST_CALL;
3177 
3178     Vals.push_back(VE.getAttributeListID(CI.getAttributes()));
3179 
3180     unsigned Flags = getOptimizationFlags(&I);
3181     Vals.push_back(CI.getCallingConv() << bitc::CALL_CCONV |
3182                    unsigned(CI.isTailCall()) << bitc::CALL_TAIL |
3183                    unsigned(CI.isMustTailCall()) << bitc::CALL_MUSTTAIL |
3184                    1 << bitc::CALL_EXPLICIT_TYPE |
3185                    unsigned(CI.isNoTailCall()) << bitc::CALL_NOTAIL |
3186                    unsigned(Flags != 0) << bitc::CALL_FMF);
3187     if (Flags != 0)
3188       Vals.push_back(Flags);
3189 
3190     Vals.push_back(VE.getTypeID(FTy));
3191     pushValueAndType(CI.getCalledOperand(), InstID, Vals); // Callee
3192 
3193     // Emit value #'s for the fixed parameters.
3194     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
3195       // Check for labels (can happen with asm labels).
3196       if (FTy->getParamType(i)->isLabelTy())
3197         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
3198       else
3199         pushValue(CI.getArgOperand(i), InstID, Vals); // fixed param.
3200     }
3201 
3202     // Emit type/value pairs for varargs params.
3203     if (FTy->isVarArg()) {
3204       for (unsigned i = FTy->getNumParams(), e = CI.arg_size(); i != e; ++i)
3205         pushValueAndType(CI.getArgOperand(i), InstID, Vals); // varargs
3206     }
3207     break;
3208   }
3209   case Instruction::VAArg:
3210     Code = bitc::FUNC_CODE_INST_VAARG;
3211     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
3212     pushValue(I.getOperand(0), InstID, Vals);                   // valist.
3213     Vals.push_back(VE.getTypeID(I.getType())); // restype.
3214     break;
3215   case Instruction::Freeze:
3216     Code = bitc::FUNC_CODE_INST_FREEZE;
3217     pushValueAndType(I.getOperand(0), InstID, Vals);
3218     break;
3219   }
3220 
3221   Stream.EmitRecord(Code, Vals, AbbrevToUse);
3222   Vals.clear();
3223 }
3224 
3225 /// Write a GlobalValue VST to the module. The purpose of this data structure is
3226 /// to allow clients to efficiently find the function body.
3227 void ModuleBitcodeWriter::writeGlobalValueSymbolTable(
3228   DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3229   // Get the offset of the VST we are writing, and backpatch it into
3230   // the VST forward declaration record.
3231   uint64_t VSTOffset = Stream.GetCurrentBitNo();
3232   // The BitcodeStartBit was the stream offset of the identification block.
3233   VSTOffset -= bitcodeStartBit();
3234   assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
3235   // Note that we add 1 here because the offset is relative to one word
3236   // before the start of the identification block, which was historically
3237   // always the start of the regular bitcode header.
3238   Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32 + 1);
3239 
3240   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3241 
3242   auto Abbv = std::make_shared<BitCodeAbbrev>();
3243   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
3244   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
3245   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
3246   unsigned FnEntryAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3247 
3248   for (const Function &F : M) {
3249     uint64_t Record[2];
3250 
3251     if (F.isDeclaration())
3252       continue;
3253 
3254     Record[0] = VE.getValueID(&F);
3255 
3256     // Save the word offset of the function (from the start of the
3257     // actual bitcode written to the stream).
3258     uint64_t BitcodeIndex = FunctionToBitcodeIndex[&F] - bitcodeStartBit();
3259     assert((BitcodeIndex & 31) == 0 && "function block not 32-bit aligned");
3260     // Note that we add 1 here because the offset is relative to one word
3261     // before the start of the identification block, which was historically
3262     // always the start of the regular bitcode header.
3263     Record[1] = BitcodeIndex / 32 + 1;
3264 
3265     Stream.EmitRecord(bitc::VST_CODE_FNENTRY, Record, FnEntryAbbrev);
3266   }
3267 
3268   Stream.ExitBlock();
3269 }
3270 
3271 /// Emit names for arguments, instructions and basic blocks in a function.
3272 void ModuleBitcodeWriter::writeFunctionLevelValueSymbolTable(
3273     const ValueSymbolTable &VST) {
3274   if (VST.empty())
3275     return;
3276 
3277   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3278 
3279   // FIXME: Set up the abbrev, we know how many values there are!
3280   // FIXME: We know if the type names can use 7-bit ascii.
3281   SmallVector<uint64_t, 64> NameVals;
3282 
3283   for (const ValueName &Name : VST) {
3284     // Figure out the encoding to use for the name.
3285     StringEncoding Bits = getStringEncoding(Name.getKey());
3286 
3287     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
3288     NameVals.push_back(VE.getValueID(Name.getValue()));
3289 
3290     // VST_CODE_ENTRY:   [valueid, namechar x N]
3291     // VST_CODE_BBENTRY: [bbid, namechar x N]
3292     unsigned Code;
3293     if (isa<BasicBlock>(Name.getValue())) {
3294       Code = bitc::VST_CODE_BBENTRY;
3295       if (Bits == SE_Char6)
3296         AbbrevToUse = VST_BBENTRY_6_ABBREV;
3297     } else {
3298       Code = bitc::VST_CODE_ENTRY;
3299       if (Bits == SE_Char6)
3300         AbbrevToUse = VST_ENTRY_6_ABBREV;
3301       else if (Bits == SE_Fixed7)
3302         AbbrevToUse = VST_ENTRY_7_ABBREV;
3303     }
3304 
3305     for (const auto P : Name.getKey())
3306       NameVals.push_back((unsigned char)P);
3307 
3308     // Emit the finished record.
3309     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
3310     NameVals.clear();
3311   }
3312 
3313   Stream.ExitBlock();
3314 }
3315 
3316 void ModuleBitcodeWriter::writeUseList(UseListOrder &&Order) {
3317   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
3318   unsigned Code;
3319   if (isa<BasicBlock>(Order.V))
3320     Code = bitc::USELIST_CODE_BB;
3321   else
3322     Code = bitc::USELIST_CODE_DEFAULT;
3323 
3324   SmallVector<uint64_t, 64> Record(Order.Shuffle.begin(), Order.Shuffle.end());
3325   Record.push_back(VE.getValueID(Order.V));
3326   Stream.EmitRecord(Code, Record);
3327 }
3328 
3329 void ModuleBitcodeWriter::writeUseListBlock(const Function *F) {
3330   assert(VE.shouldPreserveUseListOrder() &&
3331          "Expected to be preserving use-list order");
3332 
3333   auto hasMore = [&]() {
3334     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
3335   };
3336   if (!hasMore())
3337     // Nothing to do.
3338     return;
3339 
3340   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
3341   while (hasMore()) {
3342     writeUseList(std::move(VE.UseListOrders.back()));
3343     VE.UseListOrders.pop_back();
3344   }
3345   Stream.ExitBlock();
3346 }
3347 
3348 /// Emit a function body to the module stream.
3349 void ModuleBitcodeWriter::writeFunction(
3350     const Function &F,
3351     DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3352   // Save the bitcode index of the start of this function block for recording
3353   // in the VST.
3354   FunctionToBitcodeIndex[&F] = Stream.GetCurrentBitNo();
3355 
3356   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
3357   VE.incorporateFunction(F);
3358 
3359   SmallVector<unsigned, 64> Vals;
3360 
3361   // Emit the number of basic blocks, so the reader can create them ahead of
3362   // time.
3363   Vals.push_back(VE.getBasicBlocks().size());
3364   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
3365   Vals.clear();
3366 
3367   // If there are function-local constants, emit them now.
3368   unsigned CstStart, CstEnd;
3369   VE.getFunctionConstantRange(CstStart, CstEnd);
3370   writeConstants(CstStart, CstEnd, false);
3371 
3372   // If there is function-local metadata, emit it now.
3373   writeFunctionMetadata(F);
3374 
3375   // Keep a running idea of what the instruction ID is.
3376   unsigned InstID = CstEnd;
3377 
3378   bool NeedsMetadataAttachment = F.hasMetadata();
3379 
3380   DILocation *LastDL = nullptr;
3381   SmallSetVector<Function *, 4> BlockAddressUsers;
3382 
3383   // Finally, emit all the instructions, in order.
3384   for (const BasicBlock &BB : F) {
3385     for (const Instruction &I : BB) {
3386       writeInstruction(I, InstID, Vals);
3387 
3388       if (!I.getType()->isVoidTy())
3389         ++InstID;
3390 
3391       // If the instruction has metadata, write a metadata attachment later.
3392       NeedsMetadataAttachment |= I.hasMetadataOtherThanDebugLoc();
3393 
3394       // If the instruction has a debug location, emit it.
3395       DILocation *DL = I.getDebugLoc();
3396       if (!DL)
3397         continue;
3398 
3399       if (DL == LastDL) {
3400         // Just repeat the same debug loc as last time.
3401         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
3402         continue;
3403       }
3404 
3405       Vals.push_back(DL->getLine());
3406       Vals.push_back(DL->getColumn());
3407       Vals.push_back(VE.getMetadataOrNullID(DL->getScope()));
3408       Vals.push_back(VE.getMetadataOrNullID(DL->getInlinedAt()));
3409       Vals.push_back(DL->isImplicitCode());
3410       Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
3411       Vals.clear();
3412 
3413       LastDL = DL;
3414     }
3415 
3416     if (BlockAddress *BA = BlockAddress::lookup(&BB)) {
3417       SmallVector<Value *> Worklist{BA};
3418       SmallPtrSet<Value *, 8> Visited{BA};
3419       while (!Worklist.empty()) {
3420         Value *V = Worklist.pop_back_val();
3421         for (User *U : V->users()) {
3422           if (auto *I = dyn_cast<Instruction>(U)) {
3423             Function *P = I->getFunction();
3424             if (P != &F)
3425               BlockAddressUsers.insert(P);
3426           } else if (isa<Constant>(U) && !isa<GlobalValue>(U) &&
3427                      Visited.insert(U).second)
3428             Worklist.push_back(U);
3429         }
3430       }
3431     }
3432   }
3433 
3434   if (!BlockAddressUsers.empty()) {
3435     Vals.resize(BlockAddressUsers.size());
3436     for (auto I : llvm::enumerate(BlockAddressUsers))
3437       Vals[I.index()] = VE.getValueID(I.value());
3438     Stream.EmitRecord(bitc::FUNC_CODE_BLOCKADDR_USERS, Vals);
3439     Vals.clear();
3440   }
3441 
3442   // Emit names for all the instructions etc.
3443   if (auto *Symtab = F.getValueSymbolTable())
3444     writeFunctionLevelValueSymbolTable(*Symtab);
3445 
3446   if (NeedsMetadataAttachment)
3447     writeFunctionMetadataAttachment(F);
3448   if (VE.shouldPreserveUseListOrder())
3449     writeUseListBlock(&F);
3450   VE.purgeFunction();
3451   Stream.ExitBlock();
3452 }
3453 
3454 // Emit blockinfo, which defines the standard abbreviations etc.
3455 void ModuleBitcodeWriter::writeBlockInfo() {
3456   // We only want to emit block info records for blocks that have multiple
3457   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
3458   // Other blocks can define their abbrevs inline.
3459   Stream.EnterBlockInfoBlock();
3460 
3461   { // 8-bit fixed-width VST_CODE_ENTRY/VST_CODE_BBENTRY strings.
3462     auto Abbv = std::make_shared<BitCodeAbbrev>();
3463     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
3464     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3465     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3466     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3467     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3468         VST_ENTRY_8_ABBREV)
3469       llvm_unreachable("Unexpected abbrev ordering!");
3470   }
3471 
3472   { // 7-bit fixed width VST_CODE_ENTRY strings.
3473     auto Abbv = std::make_shared<BitCodeAbbrev>();
3474     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3475     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3476     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3477     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3478     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3479         VST_ENTRY_7_ABBREV)
3480       llvm_unreachable("Unexpected abbrev ordering!");
3481   }
3482   { // 6-bit char6 VST_CODE_ENTRY strings.
3483     auto Abbv = std::make_shared<BitCodeAbbrev>();
3484     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3485     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3486     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3487     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3488     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3489         VST_ENTRY_6_ABBREV)
3490       llvm_unreachable("Unexpected abbrev ordering!");
3491   }
3492   { // 6-bit char6 VST_CODE_BBENTRY strings.
3493     auto Abbv = std::make_shared<BitCodeAbbrev>();
3494     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
3495     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3496     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3497     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3498     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3499         VST_BBENTRY_6_ABBREV)
3500       llvm_unreachable("Unexpected abbrev ordering!");
3501   }
3502 
3503   { // SETTYPE abbrev for CONSTANTS_BLOCK.
3504     auto Abbv = std::make_shared<BitCodeAbbrev>();
3505     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
3506     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
3507                               VE.computeBitsRequiredForTypeIndicies()));
3508     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3509         CONSTANTS_SETTYPE_ABBREV)
3510       llvm_unreachable("Unexpected abbrev ordering!");
3511   }
3512 
3513   { // INTEGER abbrev for CONSTANTS_BLOCK.
3514     auto Abbv = std::make_shared<BitCodeAbbrev>();
3515     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
3516     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3517     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3518         CONSTANTS_INTEGER_ABBREV)
3519       llvm_unreachable("Unexpected abbrev ordering!");
3520   }
3521 
3522   { // CE_CAST abbrev for CONSTANTS_BLOCK.
3523     auto Abbv = std::make_shared<BitCodeAbbrev>();
3524     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
3525     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
3526     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
3527                               VE.computeBitsRequiredForTypeIndicies()));
3528     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
3529 
3530     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3531         CONSTANTS_CE_CAST_Abbrev)
3532       llvm_unreachable("Unexpected abbrev ordering!");
3533   }
3534   { // NULL abbrev for CONSTANTS_BLOCK.
3535     auto Abbv = std::make_shared<BitCodeAbbrev>();
3536     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
3537     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3538         CONSTANTS_NULL_Abbrev)
3539       llvm_unreachable("Unexpected abbrev ordering!");
3540   }
3541 
3542   // FIXME: This should only use space for first class types!
3543 
3544   { // INST_LOAD abbrev for FUNCTION_BLOCK.
3545     auto Abbv = std::make_shared<BitCodeAbbrev>();
3546     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
3547     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
3548     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
3549                               VE.computeBitsRequiredForTypeIndicies()));
3550     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
3551     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
3552     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3553         FUNCTION_INST_LOAD_ABBREV)
3554       llvm_unreachable("Unexpected abbrev ordering!");
3555   }
3556   { // INST_UNOP abbrev for FUNCTION_BLOCK.
3557     auto Abbv = std::make_shared<BitCodeAbbrev>();
3558     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3559     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3560     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3561     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3562         FUNCTION_INST_UNOP_ABBREV)
3563       llvm_unreachable("Unexpected abbrev ordering!");
3564   }
3565   { // INST_UNOP_FLAGS abbrev for FUNCTION_BLOCK.
3566     auto Abbv = std::make_shared<BitCodeAbbrev>();
3567     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3568     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3569     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3570     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3571     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3572         FUNCTION_INST_UNOP_FLAGS_ABBREV)
3573       llvm_unreachable("Unexpected abbrev ordering!");
3574   }
3575   { // INST_BINOP abbrev for FUNCTION_BLOCK.
3576     auto Abbv = std::make_shared<BitCodeAbbrev>();
3577     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3578     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3579     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3580     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3581     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3582         FUNCTION_INST_BINOP_ABBREV)
3583       llvm_unreachable("Unexpected abbrev ordering!");
3584   }
3585   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
3586     auto Abbv = std::make_shared<BitCodeAbbrev>();
3587     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3588     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3589     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3590     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3591     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3592     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3593         FUNCTION_INST_BINOP_FLAGS_ABBREV)
3594       llvm_unreachable("Unexpected abbrev ordering!");
3595   }
3596   { // INST_CAST abbrev for FUNCTION_BLOCK.
3597     auto Abbv = std::make_shared<BitCodeAbbrev>();
3598     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
3599     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
3600     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
3601                               VE.computeBitsRequiredForTypeIndicies()));
3602     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
3603     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3604         FUNCTION_INST_CAST_ABBREV)
3605       llvm_unreachable("Unexpected abbrev ordering!");
3606   }
3607 
3608   { // INST_RET abbrev for FUNCTION_BLOCK.
3609     auto Abbv = std::make_shared<BitCodeAbbrev>();
3610     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3611     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3612         FUNCTION_INST_RET_VOID_ABBREV)
3613       llvm_unreachable("Unexpected abbrev ordering!");
3614   }
3615   { // INST_RET abbrev for FUNCTION_BLOCK.
3616     auto Abbv = std::make_shared<BitCodeAbbrev>();
3617     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3618     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
3619     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3620         FUNCTION_INST_RET_VAL_ABBREV)
3621       llvm_unreachable("Unexpected abbrev ordering!");
3622   }
3623   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
3624     auto Abbv = std::make_shared<BitCodeAbbrev>();
3625     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
3626     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3627         FUNCTION_INST_UNREACHABLE_ABBREV)
3628       llvm_unreachable("Unexpected abbrev ordering!");
3629   }
3630   {
3631     auto Abbv = std::make_shared<BitCodeAbbrev>();
3632     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_GEP));
3633     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
3634     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, // dest ty
3635                               Log2_32_Ceil(VE.getTypes().size() + 1)));
3636     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3637     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
3638     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3639         FUNCTION_INST_GEP_ABBREV)
3640       llvm_unreachable("Unexpected abbrev ordering!");
3641   }
3642 
3643   Stream.ExitBlock();
3644 }
3645 
3646 /// Write the module path strings, currently only used when generating
3647 /// a combined index file.
3648 void IndexBitcodeWriter::writeModStrings() {
3649   Stream.EnterSubblock(bitc::MODULE_STRTAB_BLOCK_ID, 3);
3650 
3651   // TODO: See which abbrev sizes we actually need to emit
3652 
3653   // 8-bit fixed-width MST_ENTRY strings.
3654   auto Abbv = std::make_shared<BitCodeAbbrev>();
3655   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3656   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3657   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3658   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3659   unsigned Abbrev8Bit = Stream.EmitAbbrev(std::move(Abbv));
3660 
3661   // 7-bit fixed width MST_ENTRY strings.
3662   Abbv = std::make_shared<BitCodeAbbrev>();
3663   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3664   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3665   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3666   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3667   unsigned Abbrev7Bit = Stream.EmitAbbrev(std::move(Abbv));
3668 
3669   // 6-bit char6 MST_ENTRY strings.
3670   Abbv = std::make_shared<BitCodeAbbrev>();
3671   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3672   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3673   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3674   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3675   unsigned Abbrev6Bit = Stream.EmitAbbrev(std::move(Abbv));
3676 
3677   // Module Hash, 160 bits SHA1. Optionally, emitted after each MST_CODE_ENTRY.
3678   Abbv = std::make_shared<BitCodeAbbrev>();
3679   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_HASH));
3680   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3681   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3682   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3683   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3684   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3685   unsigned AbbrevHash = Stream.EmitAbbrev(std::move(Abbv));
3686 
3687   SmallVector<unsigned, 64> Vals;
3688   forEachModule(
3689       [&](const StringMapEntry<std::pair<uint64_t, ModuleHash>> &MPSE) {
3690         StringRef Key = MPSE.getKey();
3691         const auto &Value = MPSE.getValue();
3692         StringEncoding Bits = getStringEncoding(Key);
3693         unsigned AbbrevToUse = Abbrev8Bit;
3694         if (Bits == SE_Char6)
3695           AbbrevToUse = Abbrev6Bit;
3696         else if (Bits == SE_Fixed7)
3697           AbbrevToUse = Abbrev7Bit;
3698 
3699         Vals.push_back(Value.first);
3700         Vals.append(Key.begin(), Key.end());
3701 
3702         // Emit the finished record.
3703         Stream.EmitRecord(bitc::MST_CODE_ENTRY, Vals, AbbrevToUse);
3704 
3705         // Emit an optional hash for the module now
3706         const auto &Hash = Value.second;
3707         if (llvm::any_of(Hash, [](uint32_t H) { return H; })) {
3708           Vals.assign(Hash.begin(), Hash.end());
3709           // Emit the hash record.
3710           Stream.EmitRecord(bitc::MST_CODE_HASH, Vals, AbbrevHash);
3711         }
3712 
3713         Vals.clear();
3714       });
3715   Stream.ExitBlock();
3716 }
3717 
3718 /// Write the function type metadata related records that need to appear before
3719 /// a function summary entry (whether per-module or combined).
3720 template <typename Fn>
3721 static void writeFunctionTypeMetadataRecords(BitstreamWriter &Stream,
3722                                              FunctionSummary *FS,
3723                                              Fn GetValueID) {
3724   if (!FS->type_tests().empty())
3725     Stream.EmitRecord(bitc::FS_TYPE_TESTS, FS->type_tests());
3726 
3727   SmallVector<uint64_t, 64> Record;
3728 
3729   auto WriteVFuncIdVec = [&](uint64_t Ty,
3730                              ArrayRef<FunctionSummary::VFuncId> VFs) {
3731     if (VFs.empty())
3732       return;
3733     Record.clear();
3734     for (auto &VF : VFs) {
3735       Record.push_back(VF.GUID);
3736       Record.push_back(VF.Offset);
3737     }
3738     Stream.EmitRecord(Ty, Record);
3739   };
3740 
3741   WriteVFuncIdVec(bitc::FS_TYPE_TEST_ASSUME_VCALLS,
3742                   FS->type_test_assume_vcalls());
3743   WriteVFuncIdVec(bitc::FS_TYPE_CHECKED_LOAD_VCALLS,
3744                   FS->type_checked_load_vcalls());
3745 
3746   auto WriteConstVCallVec = [&](uint64_t Ty,
3747                                 ArrayRef<FunctionSummary::ConstVCall> VCs) {
3748     for (auto &VC : VCs) {
3749       Record.clear();
3750       Record.push_back(VC.VFunc.GUID);
3751       Record.push_back(VC.VFunc.Offset);
3752       llvm::append_range(Record, VC.Args);
3753       Stream.EmitRecord(Ty, Record);
3754     }
3755   };
3756 
3757   WriteConstVCallVec(bitc::FS_TYPE_TEST_ASSUME_CONST_VCALL,
3758                      FS->type_test_assume_const_vcalls());
3759   WriteConstVCallVec(bitc::FS_TYPE_CHECKED_LOAD_CONST_VCALL,
3760                      FS->type_checked_load_const_vcalls());
3761 
3762   auto WriteRange = [&](ConstantRange Range) {
3763     Range = Range.sextOrTrunc(FunctionSummary::ParamAccess::RangeWidth);
3764     assert(Range.getLower().getNumWords() == 1);
3765     assert(Range.getUpper().getNumWords() == 1);
3766     emitSignedInt64(Record, *Range.getLower().getRawData());
3767     emitSignedInt64(Record, *Range.getUpper().getRawData());
3768   };
3769 
3770   if (!FS->paramAccesses().empty()) {
3771     Record.clear();
3772     for (auto &Arg : FS->paramAccesses()) {
3773       size_t UndoSize = Record.size();
3774       Record.push_back(Arg.ParamNo);
3775       WriteRange(Arg.Use);
3776       Record.push_back(Arg.Calls.size());
3777       for (auto &Call : Arg.Calls) {
3778         Record.push_back(Call.ParamNo);
3779         Optional<unsigned> ValueID = GetValueID(Call.Callee);
3780         if (!ValueID) {
3781           // If ValueID is unknown we can't drop just this call, we must drop
3782           // entire parameter.
3783           Record.resize(UndoSize);
3784           break;
3785         }
3786         Record.push_back(*ValueID);
3787         WriteRange(Call.Offsets);
3788       }
3789     }
3790     if (!Record.empty())
3791       Stream.EmitRecord(bitc::FS_PARAM_ACCESS, Record);
3792   }
3793 }
3794 
3795 /// Collect type IDs from type tests used by function.
3796 static void
3797 getReferencedTypeIds(FunctionSummary *FS,
3798                      std::set<GlobalValue::GUID> &ReferencedTypeIds) {
3799   if (!FS->type_tests().empty())
3800     for (auto &TT : FS->type_tests())
3801       ReferencedTypeIds.insert(TT);
3802 
3803   auto GetReferencedTypesFromVFuncIdVec =
3804       [&](ArrayRef<FunctionSummary::VFuncId> VFs) {
3805         for (auto &VF : VFs)
3806           ReferencedTypeIds.insert(VF.GUID);
3807       };
3808 
3809   GetReferencedTypesFromVFuncIdVec(FS->type_test_assume_vcalls());
3810   GetReferencedTypesFromVFuncIdVec(FS->type_checked_load_vcalls());
3811 
3812   auto GetReferencedTypesFromConstVCallVec =
3813       [&](ArrayRef<FunctionSummary::ConstVCall> VCs) {
3814         for (auto &VC : VCs)
3815           ReferencedTypeIds.insert(VC.VFunc.GUID);
3816       };
3817 
3818   GetReferencedTypesFromConstVCallVec(FS->type_test_assume_const_vcalls());
3819   GetReferencedTypesFromConstVCallVec(FS->type_checked_load_const_vcalls());
3820 }
3821 
3822 static void writeWholeProgramDevirtResolutionByArg(
3823     SmallVector<uint64_t, 64> &NameVals, const std::vector<uint64_t> &args,
3824     const WholeProgramDevirtResolution::ByArg &ByArg) {
3825   NameVals.push_back(args.size());
3826   llvm::append_range(NameVals, args);
3827 
3828   NameVals.push_back(ByArg.TheKind);
3829   NameVals.push_back(ByArg.Info);
3830   NameVals.push_back(ByArg.Byte);
3831   NameVals.push_back(ByArg.Bit);
3832 }
3833 
3834 static void writeWholeProgramDevirtResolution(
3835     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3836     uint64_t Id, const WholeProgramDevirtResolution &Wpd) {
3837   NameVals.push_back(Id);
3838 
3839   NameVals.push_back(Wpd.TheKind);
3840   NameVals.push_back(StrtabBuilder.add(Wpd.SingleImplName));
3841   NameVals.push_back(Wpd.SingleImplName.size());
3842 
3843   NameVals.push_back(Wpd.ResByArg.size());
3844   for (auto &A : Wpd.ResByArg)
3845     writeWholeProgramDevirtResolutionByArg(NameVals, A.first, A.second);
3846 }
3847 
3848 static void writeTypeIdSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
3849                                      StringTableBuilder &StrtabBuilder,
3850                                      const std::string &Id,
3851                                      const TypeIdSummary &Summary) {
3852   NameVals.push_back(StrtabBuilder.add(Id));
3853   NameVals.push_back(Id.size());
3854 
3855   NameVals.push_back(Summary.TTRes.TheKind);
3856   NameVals.push_back(Summary.TTRes.SizeM1BitWidth);
3857   NameVals.push_back(Summary.TTRes.AlignLog2);
3858   NameVals.push_back(Summary.TTRes.SizeM1);
3859   NameVals.push_back(Summary.TTRes.BitMask);
3860   NameVals.push_back(Summary.TTRes.InlineBits);
3861 
3862   for (auto &W : Summary.WPDRes)
3863     writeWholeProgramDevirtResolution(NameVals, StrtabBuilder, W.first,
3864                                       W.second);
3865 }
3866 
3867 static void writeTypeIdCompatibleVtableSummaryRecord(
3868     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3869     const std::string &Id, const TypeIdCompatibleVtableInfo &Summary,
3870     ValueEnumerator &VE) {
3871   NameVals.push_back(StrtabBuilder.add(Id));
3872   NameVals.push_back(Id.size());
3873 
3874   for (auto &P : Summary) {
3875     NameVals.push_back(P.AddressPointOffset);
3876     NameVals.push_back(VE.getValueID(P.VTableVI.getValue()));
3877   }
3878 }
3879 
3880 // Helper to emit a single function summary record.
3881 void ModuleBitcodeWriterBase::writePerModuleFunctionSummaryRecord(
3882     SmallVector<uint64_t, 64> &NameVals, GlobalValueSummary *Summary,
3883     unsigned ValueID, unsigned FSCallsAbbrev, unsigned FSCallsProfileAbbrev,
3884     const Function &F) {
3885   NameVals.push_back(ValueID);
3886 
3887   FunctionSummary *FS = cast<FunctionSummary>(Summary);
3888 
3889   writeFunctionTypeMetadataRecords(
3890       Stream, FS, [&](const ValueInfo &VI) -> Optional<unsigned> {
3891         return {VE.getValueID(VI.getValue())};
3892       });
3893 
3894   auto SpecialRefCnts = FS->specialRefCounts();
3895   NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
3896   NameVals.push_back(FS->instCount());
3897   NameVals.push_back(getEncodedFFlags(FS->fflags()));
3898   NameVals.push_back(FS->refs().size());
3899   NameVals.push_back(SpecialRefCnts.first);  // rorefcnt
3900   NameVals.push_back(SpecialRefCnts.second); // worefcnt
3901 
3902   for (auto &RI : FS->refs())
3903     NameVals.push_back(VE.getValueID(RI.getValue()));
3904 
3905   bool HasProfileData =
3906       F.hasProfileData() || ForceSummaryEdgesCold != FunctionSummary::FSHT_None;
3907   for (auto &ECI : FS->calls()) {
3908     NameVals.push_back(getValueId(ECI.first));
3909     if (HasProfileData)
3910       NameVals.push_back(static_cast<uint8_t>(ECI.second.Hotness));
3911     else if (WriteRelBFToSummary)
3912       NameVals.push_back(ECI.second.RelBlockFreq);
3913   }
3914 
3915   unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
3916   unsigned Code =
3917       (HasProfileData ? bitc::FS_PERMODULE_PROFILE
3918                       : (WriteRelBFToSummary ? bitc::FS_PERMODULE_RELBF
3919                                              : bitc::FS_PERMODULE));
3920 
3921   // Emit the finished record.
3922   Stream.EmitRecord(Code, NameVals, FSAbbrev);
3923   NameVals.clear();
3924 }
3925 
3926 // Collect the global value references in the given variable's initializer,
3927 // and emit them in a summary record.
3928 void ModuleBitcodeWriterBase::writeModuleLevelReferences(
3929     const GlobalVariable &V, SmallVector<uint64_t, 64> &NameVals,
3930     unsigned FSModRefsAbbrev, unsigned FSModVTableRefsAbbrev) {
3931   auto VI = Index->getValueInfo(V.getGUID());
3932   if (!VI || VI.getSummaryList().empty()) {
3933     // Only declarations should not have a summary (a declaration might however
3934     // have a summary if the def was in module level asm).
3935     assert(V.isDeclaration());
3936     return;
3937   }
3938   auto *Summary = VI.getSummaryList()[0].get();
3939   NameVals.push_back(VE.getValueID(&V));
3940   GlobalVarSummary *VS = cast<GlobalVarSummary>(Summary);
3941   NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
3942   NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
3943 
3944   auto VTableFuncs = VS->vTableFuncs();
3945   if (!VTableFuncs.empty())
3946     NameVals.push_back(VS->refs().size());
3947 
3948   unsigned SizeBeforeRefs = NameVals.size();
3949   for (auto &RI : VS->refs())
3950     NameVals.push_back(VE.getValueID(RI.getValue()));
3951   // Sort the refs for determinism output, the vector returned by FS->refs() has
3952   // been initialized from a DenseSet.
3953   llvm::sort(drop_begin(NameVals, SizeBeforeRefs));
3954 
3955   if (VTableFuncs.empty())
3956     Stream.EmitRecord(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS, NameVals,
3957                       FSModRefsAbbrev);
3958   else {
3959     // VTableFuncs pairs should already be sorted by offset.
3960     for (auto &P : VTableFuncs) {
3961       NameVals.push_back(VE.getValueID(P.FuncVI.getValue()));
3962       NameVals.push_back(P.VTableOffset);
3963     }
3964 
3965     Stream.EmitRecord(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS, NameVals,
3966                       FSModVTableRefsAbbrev);
3967   }
3968   NameVals.clear();
3969 }
3970 
3971 /// Emit the per-module summary section alongside the rest of
3972 /// the module's bitcode.
3973 void ModuleBitcodeWriterBase::writePerModuleGlobalValueSummary() {
3974   // By default we compile with ThinLTO if the module has a summary, but the
3975   // client can request full LTO with a module flag.
3976   bool IsThinLTO = true;
3977   if (auto *MD =
3978           mdconst::extract_or_null<ConstantInt>(M.getModuleFlag("ThinLTO")))
3979     IsThinLTO = MD->getZExtValue();
3980   Stream.EnterSubblock(IsThinLTO ? bitc::GLOBALVAL_SUMMARY_BLOCK_ID
3981                                  : bitc::FULL_LTO_GLOBALVAL_SUMMARY_BLOCK_ID,
3982                        4);
3983 
3984   Stream.EmitRecord(
3985       bitc::FS_VERSION,
3986       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
3987 
3988   // Write the index flags.
3989   uint64_t Flags = 0;
3990   // Bits 1-3 are set only in the combined index, skip them.
3991   if (Index->enableSplitLTOUnit())
3992     Flags |= 0x8;
3993   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Flags});
3994 
3995   if (Index->begin() == Index->end()) {
3996     Stream.ExitBlock();
3997     return;
3998   }
3999 
4000   for (const auto &GVI : valueIds()) {
4001     Stream.EmitRecord(bitc::FS_VALUE_GUID,
4002                       ArrayRef<uint64_t>{GVI.second, GVI.first});
4003   }
4004 
4005   // Abbrev for FS_PERMODULE_PROFILE.
4006   auto Abbv = std::make_shared<BitCodeAbbrev>();
4007   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_PROFILE));
4008   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4009   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4010   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4011   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4012   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4013   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4014   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4015   // numrefs x valueid, n x (valueid, hotness)
4016   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4017   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4018   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4019 
4020   // Abbrev for FS_PERMODULE or FS_PERMODULE_RELBF.
4021   Abbv = std::make_shared<BitCodeAbbrev>();
4022   if (WriteRelBFToSummary)
4023     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_RELBF));
4024   else
4025     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE));
4026   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4027   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4028   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4029   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4030   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4031   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4032   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4033   // numrefs x valueid, n x (valueid [, rel_block_freq])
4034   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4035   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4036   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4037 
4038   // Abbrev for FS_PERMODULE_GLOBALVAR_INIT_REFS.
4039   Abbv = std::make_shared<BitCodeAbbrev>();
4040   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS));
4041   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
4042   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
4043   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));  // valueids
4044   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4045   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4046 
4047   // Abbrev for FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS.
4048   Abbv = std::make_shared<BitCodeAbbrev>();
4049   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS));
4050   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
4051   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
4052   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numrefs
4053   // numrefs x valueid, n x (valueid , offset)
4054   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4055   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4056   unsigned FSModVTableRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4057 
4058   // Abbrev for FS_ALIAS.
4059   Abbv = std::make_shared<BitCodeAbbrev>();
4060   Abbv->Add(BitCodeAbbrevOp(bitc::FS_ALIAS));
4061   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4062   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4063   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4064   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4065 
4066   // Abbrev for FS_TYPE_ID_METADATA
4067   Abbv = std::make_shared<BitCodeAbbrev>();
4068   Abbv->Add(BitCodeAbbrevOp(bitc::FS_TYPE_ID_METADATA));
4069   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid strtab index
4070   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid length
4071   // n x (valueid , offset)
4072   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4073   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4074   unsigned TypeIdCompatibleVtableAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4075 
4076   SmallVector<uint64_t, 64> NameVals;
4077   // Iterate over the list of functions instead of the Index to
4078   // ensure the ordering is stable.
4079   for (const Function &F : M) {
4080     // Summary emission does not support anonymous functions, they have to
4081     // renamed using the anonymous function renaming pass.
4082     if (!F.hasName())
4083       report_fatal_error("Unexpected anonymous function when writing summary");
4084 
4085     ValueInfo VI = Index->getValueInfo(F.getGUID());
4086     if (!VI || VI.getSummaryList().empty()) {
4087       // Only declarations should not have a summary (a declaration might
4088       // however have a summary if the def was in module level asm).
4089       assert(F.isDeclaration());
4090       continue;
4091     }
4092     auto *Summary = VI.getSummaryList()[0].get();
4093     writePerModuleFunctionSummaryRecord(NameVals, Summary, VE.getValueID(&F),
4094                                         FSCallsAbbrev, FSCallsProfileAbbrev, F);
4095   }
4096 
4097   // Capture references from GlobalVariable initializers, which are outside
4098   // of a function scope.
4099   for (const GlobalVariable &G : M.globals())
4100     writeModuleLevelReferences(G, NameVals, FSModRefsAbbrev,
4101                                FSModVTableRefsAbbrev);
4102 
4103   for (const GlobalAlias &A : M.aliases()) {
4104     auto *Aliasee = A.getAliaseeObject();
4105     // Skip ifunc and nameless functions which don't have an entry in the
4106     // summary.
4107     if (!Aliasee->hasName() || isa<GlobalIFunc>(Aliasee))
4108       continue;
4109     auto AliasId = VE.getValueID(&A);
4110     auto AliaseeId = VE.getValueID(Aliasee);
4111     NameVals.push_back(AliasId);
4112     auto *Summary = Index->getGlobalValueSummary(A);
4113     AliasSummary *AS = cast<AliasSummary>(Summary);
4114     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
4115     NameVals.push_back(AliaseeId);
4116     Stream.EmitRecord(bitc::FS_ALIAS, NameVals, FSAliasAbbrev);
4117     NameVals.clear();
4118   }
4119 
4120   for (auto &S : Index->typeIdCompatibleVtableMap()) {
4121     writeTypeIdCompatibleVtableSummaryRecord(NameVals, StrtabBuilder, S.first,
4122                                              S.second, VE);
4123     Stream.EmitRecord(bitc::FS_TYPE_ID_METADATA, NameVals,
4124                       TypeIdCompatibleVtableAbbrev);
4125     NameVals.clear();
4126   }
4127 
4128   Stream.EmitRecord(bitc::FS_BLOCK_COUNT,
4129                     ArrayRef<uint64_t>{Index->getBlockCount()});
4130 
4131   Stream.ExitBlock();
4132 }
4133 
4134 /// Emit the combined summary section into the combined index file.
4135 void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
4136   Stream.EnterSubblock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID, 3);
4137   Stream.EmitRecord(
4138       bitc::FS_VERSION,
4139       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
4140 
4141   // Write the index flags.
4142   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Index.getFlags()});
4143 
4144   for (const auto &GVI : valueIds()) {
4145     Stream.EmitRecord(bitc::FS_VALUE_GUID,
4146                       ArrayRef<uint64_t>{GVI.second, GVI.first});
4147   }
4148 
4149   // Abbrev for FS_COMBINED.
4150   auto Abbv = std::make_shared<BitCodeAbbrev>();
4151   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED));
4152   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4153   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4154   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4155   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4156   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4157   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
4158   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4159   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4160   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4161   // numrefs x valueid, n x (valueid)
4162   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4163   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4164   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4165 
4166   // Abbrev for FS_COMBINED_PROFILE.
4167   Abbv = std::make_shared<BitCodeAbbrev>();
4168   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_PROFILE));
4169   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4170   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4171   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4172   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4173   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4174   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
4175   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4176   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4177   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4178   // numrefs x valueid, n x (valueid, hotness)
4179   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4180   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4181   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4182 
4183   // Abbrev for FS_COMBINED_GLOBALVAR_INIT_REFS.
4184   Abbv = std::make_shared<BitCodeAbbrev>();
4185   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS));
4186   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4187   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4188   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4189   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));    // valueids
4190   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4191   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4192 
4193   // Abbrev for FS_COMBINED_ALIAS.
4194   Abbv = std::make_shared<BitCodeAbbrev>();
4195   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_ALIAS));
4196   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4197   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4198   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4199   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4200   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4201 
4202   // The aliases are emitted as a post-pass, and will point to the value
4203   // id of the aliasee. Save them in a vector for post-processing.
4204   SmallVector<AliasSummary *, 64> Aliases;
4205 
4206   // Save the value id for each summary for alias emission.
4207   DenseMap<const GlobalValueSummary *, unsigned> SummaryToValueIdMap;
4208 
4209   SmallVector<uint64_t, 64> NameVals;
4210 
4211   // Set that will be populated during call to writeFunctionTypeMetadataRecords
4212   // with the type ids referenced by this index file.
4213   std::set<GlobalValue::GUID> ReferencedTypeIds;
4214 
4215   // For local linkage, we also emit the original name separately
4216   // immediately after the record.
4217   auto MaybeEmitOriginalName = [&](GlobalValueSummary &S) {
4218     // We don't need to emit the original name if we are writing the index for
4219     // distributed backends (in which case ModuleToSummariesForIndex is
4220     // non-null). The original name is only needed during the thin link, since
4221     // for SamplePGO the indirect call targets for local functions have
4222     // have the original name annotated in profile.
4223     // Continue to emit it when writing out the entire combined index, which is
4224     // used in testing the thin link via llvm-lto.
4225     if (ModuleToSummariesForIndex || !GlobalValue::isLocalLinkage(S.linkage()))
4226       return;
4227     NameVals.push_back(S.getOriginalName());
4228     Stream.EmitRecord(bitc::FS_COMBINED_ORIGINAL_NAME, NameVals);
4229     NameVals.clear();
4230   };
4231 
4232   std::set<GlobalValue::GUID> DefOrUseGUIDs;
4233   forEachSummary([&](GVInfo I, bool IsAliasee) {
4234     GlobalValueSummary *S = I.second;
4235     assert(S);
4236     DefOrUseGUIDs.insert(I.first);
4237     for (const ValueInfo &VI : S->refs())
4238       DefOrUseGUIDs.insert(VI.getGUID());
4239 
4240     auto ValueId = getValueId(I.first);
4241     assert(ValueId);
4242     SummaryToValueIdMap[S] = *ValueId;
4243 
4244     // If this is invoked for an aliasee, we want to record the above
4245     // mapping, but then not emit a summary entry (if the aliasee is
4246     // to be imported, we will invoke this separately with IsAliasee=false).
4247     if (IsAliasee)
4248       return;
4249 
4250     if (auto *AS = dyn_cast<AliasSummary>(S)) {
4251       // Will process aliases as a post-pass because the reader wants all
4252       // global to be loaded first.
4253       Aliases.push_back(AS);
4254       return;
4255     }
4256 
4257     if (auto *VS = dyn_cast<GlobalVarSummary>(S)) {
4258       NameVals.push_back(*ValueId);
4259       NameVals.push_back(Index.getModuleId(VS->modulePath()));
4260       NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
4261       NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
4262       for (auto &RI : VS->refs()) {
4263         auto RefValueId = getValueId(RI.getGUID());
4264         if (!RefValueId)
4265           continue;
4266         NameVals.push_back(*RefValueId);
4267       }
4268 
4269       // Emit the finished record.
4270       Stream.EmitRecord(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS, NameVals,
4271                         FSModRefsAbbrev);
4272       NameVals.clear();
4273       MaybeEmitOriginalName(*S);
4274       return;
4275     }
4276 
4277     auto GetValueId = [&](const ValueInfo &VI) -> Optional<unsigned> {
4278       return getValueId(VI.getGUID());
4279     };
4280 
4281     auto *FS = cast<FunctionSummary>(S);
4282     writeFunctionTypeMetadataRecords(Stream, FS, GetValueId);
4283     getReferencedTypeIds(FS, ReferencedTypeIds);
4284 
4285     NameVals.push_back(*ValueId);
4286     NameVals.push_back(Index.getModuleId(FS->modulePath()));
4287     NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
4288     NameVals.push_back(FS->instCount());
4289     NameVals.push_back(getEncodedFFlags(FS->fflags()));
4290     NameVals.push_back(FS->entryCount());
4291 
4292     // Fill in below
4293     NameVals.push_back(0); // numrefs
4294     NameVals.push_back(0); // rorefcnt
4295     NameVals.push_back(0); // worefcnt
4296 
4297     unsigned Count = 0, RORefCnt = 0, WORefCnt = 0;
4298     for (auto &RI : FS->refs()) {
4299       auto RefValueId = getValueId(RI.getGUID());
4300       if (!RefValueId)
4301         continue;
4302       NameVals.push_back(*RefValueId);
4303       if (RI.isReadOnly())
4304         RORefCnt++;
4305       else if (RI.isWriteOnly())
4306         WORefCnt++;
4307       Count++;
4308     }
4309     NameVals[6] = Count;
4310     NameVals[7] = RORefCnt;
4311     NameVals[8] = WORefCnt;
4312 
4313     bool HasProfileData = false;
4314     for (auto &EI : FS->calls()) {
4315       HasProfileData |=
4316           EI.second.getHotness() != CalleeInfo::HotnessType::Unknown;
4317       if (HasProfileData)
4318         break;
4319     }
4320 
4321     for (auto &EI : FS->calls()) {
4322       // If this GUID doesn't have a value id, it doesn't have a function
4323       // summary and we don't need to record any calls to it.
4324       Optional<unsigned> CallValueId = GetValueId(EI.first);
4325       if (!CallValueId)
4326         continue;
4327       NameVals.push_back(*CallValueId);
4328       if (HasProfileData)
4329         NameVals.push_back(static_cast<uint8_t>(EI.second.Hotness));
4330     }
4331 
4332     unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
4333     unsigned Code =
4334         (HasProfileData ? bitc::FS_COMBINED_PROFILE : bitc::FS_COMBINED);
4335 
4336     // Emit the finished record.
4337     Stream.EmitRecord(Code, NameVals, FSAbbrev);
4338     NameVals.clear();
4339     MaybeEmitOriginalName(*S);
4340   });
4341 
4342   for (auto *AS : Aliases) {
4343     auto AliasValueId = SummaryToValueIdMap[AS];
4344     assert(AliasValueId);
4345     NameVals.push_back(AliasValueId);
4346     NameVals.push_back(Index.getModuleId(AS->modulePath()));
4347     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
4348     auto AliaseeValueId = SummaryToValueIdMap[&AS->getAliasee()];
4349     assert(AliaseeValueId);
4350     NameVals.push_back(AliaseeValueId);
4351 
4352     // Emit the finished record.
4353     Stream.EmitRecord(bitc::FS_COMBINED_ALIAS, NameVals, FSAliasAbbrev);
4354     NameVals.clear();
4355     MaybeEmitOriginalName(*AS);
4356 
4357     if (auto *FS = dyn_cast<FunctionSummary>(&AS->getAliasee()))
4358       getReferencedTypeIds(FS, ReferencedTypeIds);
4359   }
4360 
4361   if (!Index.cfiFunctionDefs().empty()) {
4362     for (auto &S : Index.cfiFunctionDefs()) {
4363       if (DefOrUseGUIDs.count(
4364               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4365         NameVals.push_back(StrtabBuilder.add(S));
4366         NameVals.push_back(S.size());
4367       }
4368     }
4369     if (!NameVals.empty()) {
4370       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DEFS, NameVals);
4371       NameVals.clear();
4372     }
4373   }
4374 
4375   if (!Index.cfiFunctionDecls().empty()) {
4376     for (auto &S : Index.cfiFunctionDecls()) {
4377       if (DefOrUseGUIDs.count(
4378               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4379         NameVals.push_back(StrtabBuilder.add(S));
4380         NameVals.push_back(S.size());
4381       }
4382     }
4383     if (!NameVals.empty()) {
4384       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DECLS, NameVals);
4385       NameVals.clear();
4386     }
4387   }
4388 
4389   // Walk the GUIDs that were referenced, and write the
4390   // corresponding type id records.
4391   for (auto &T : ReferencedTypeIds) {
4392     auto TidIter = Index.typeIds().equal_range(T);
4393     for (auto It = TidIter.first; It != TidIter.second; ++It) {
4394       writeTypeIdSummaryRecord(NameVals, StrtabBuilder, It->second.first,
4395                                It->second.second);
4396       Stream.EmitRecord(bitc::FS_TYPE_ID, NameVals);
4397       NameVals.clear();
4398     }
4399   }
4400 
4401   Stream.EmitRecord(bitc::FS_BLOCK_COUNT,
4402                     ArrayRef<uint64_t>{Index.getBlockCount()});
4403 
4404   Stream.ExitBlock();
4405 }
4406 
4407 /// Create the "IDENTIFICATION_BLOCK_ID" containing a single string with the
4408 /// current llvm version, and a record for the epoch number.
4409 static void writeIdentificationBlock(BitstreamWriter &Stream) {
4410   Stream.EnterSubblock(bitc::IDENTIFICATION_BLOCK_ID, 5);
4411 
4412   // Write the "user readable" string identifying the bitcode producer
4413   auto Abbv = std::make_shared<BitCodeAbbrev>();
4414   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_STRING));
4415   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4416   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
4417   auto StringAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4418   writeStringRecord(Stream, bitc::IDENTIFICATION_CODE_STRING,
4419                     "LLVM" LLVM_VERSION_STRING, StringAbbrev);
4420 
4421   // Write the epoch version
4422   Abbv = std::make_shared<BitCodeAbbrev>();
4423   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_EPOCH));
4424   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
4425   auto EpochAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4426   constexpr std::array<unsigned, 1> Vals = {{bitc::BITCODE_CURRENT_EPOCH}};
4427   Stream.EmitRecord(bitc::IDENTIFICATION_CODE_EPOCH, Vals, EpochAbbrev);
4428   Stream.ExitBlock();
4429 }
4430 
4431 void ModuleBitcodeWriter::writeModuleHash(size_t BlockStartPos) {
4432   // Emit the module's hash.
4433   // MODULE_CODE_HASH: [5*i32]
4434   if (GenerateHash) {
4435     uint32_t Vals[5];
4436     Hasher.update(ArrayRef<uint8_t>((const uint8_t *)&(Buffer)[BlockStartPos],
4437                                     Buffer.size() - BlockStartPos));
4438     std::array<uint8_t, 20> Hash = Hasher.result();
4439     for (int Pos = 0; Pos < 20; Pos += 4) {
4440       Vals[Pos / 4] = support::endian::read32be(Hash.data() + Pos);
4441     }
4442 
4443     // Emit the finished record.
4444     Stream.EmitRecord(bitc::MODULE_CODE_HASH, Vals);
4445 
4446     if (ModHash)
4447       // Save the written hash value.
4448       llvm::copy(Vals, std::begin(*ModHash));
4449   }
4450 }
4451 
4452 void ModuleBitcodeWriter::write() {
4453   writeIdentificationBlock(Stream);
4454 
4455   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4456   size_t BlockStartPos = Buffer.size();
4457 
4458   writeModuleVersion();
4459 
4460   // Emit blockinfo, which defines the standard abbreviations etc.
4461   writeBlockInfo();
4462 
4463   // Emit information describing all of the types in the module.
4464   writeTypeTable();
4465 
4466   // Emit information about attribute groups.
4467   writeAttributeGroupTable();
4468 
4469   // Emit information about parameter attributes.
4470   writeAttributeTable();
4471 
4472   writeComdats();
4473 
4474   // Emit top-level description of module, including target triple, inline asm,
4475   // descriptors for global variables, and function prototype info.
4476   writeModuleInfo();
4477 
4478   // Emit constants.
4479   writeModuleConstants();
4480 
4481   // Emit metadata kind names.
4482   writeModuleMetadataKinds();
4483 
4484   // Emit metadata.
4485   writeModuleMetadata();
4486 
4487   // Emit module-level use-lists.
4488   if (VE.shouldPreserveUseListOrder())
4489     writeUseListBlock(nullptr);
4490 
4491   writeOperandBundleTags();
4492   writeSyncScopeNames();
4493 
4494   // Emit function bodies.
4495   DenseMap<const Function *, uint64_t> FunctionToBitcodeIndex;
4496   for (const Function &F : M)
4497     if (!F.isDeclaration())
4498       writeFunction(F, FunctionToBitcodeIndex);
4499 
4500   // Need to write after the above call to WriteFunction which populates
4501   // the summary information in the index.
4502   if (Index)
4503     writePerModuleGlobalValueSummary();
4504 
4505   writeGlobalValueSymbolTable(FunctionToBitcodeIndex);
4506 
4507   writeModuleHash(BlockStartPos);
4508 
4509   Stream.ExitBlock();
4510 }
4511 
4512 static void writeInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
4513                                uint32_t &Position) {
4514   support::endian::write32le(&Buffer[Position], Value);
4515   Position += 4;
4516 }
4517 
4518 /// If generating a bc file on darwin, we have to emit a
4519 /// header and trailer to make it compatible with the system archiver.  To do
4520 /// this we emit the following header, and then emit a trailer that pads the
4521 /// file out to be a multiple of 16 bytes.
4522 ///
4523 /// struct bc_header {
4524 ///   uint32_t Magic;         // 0x0B17C0DE
4525 ///   uint32_t Version;       // Version, currently always 0.
4526 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
4527 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
4528 ///   uint32_t CPUType;       // CPU specifier.
4529 ///   ... potentially more later ...
4530 /// };
4531 static void emitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
4532                                          const Triple &TT) {
4533   unsigned CPUType = ~0U;
4534 
4535   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
4536   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
4537   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
4538   // specific constants here because they are implicitly part of the Darwin ABI.
4539   enum {
4540     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
4541     DARWIN_CPU_TYPE_X86        = 7,
4542     DARWIN_CPU_TYPE_ARM        = 12,
4543     DARWIN_CPU_TYPE_POWERPC    = 18
4544   };
4545 
4546   Triple::ArchType Arch = TT.getArch();
4547   if (Arch == Triple::x86_64)
4548     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
4549   else if (Arch == Triple::x86)
4550     CPUType = DARWIN_CPU_TYPE_X86;
4551   else if (Arch == Triple::ppc)
4552     CPUType = DARWIN_CPU_TYPE_POWERPC;
4553   else if (Arch == Triple::ppc64)
4554     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
4555   else if (Arch == Triple::arm || Arch == Triple::thumb)
4556     CPUType = DARWIN_CPU_TYPE_ARM;
4557 
4558   // Traditional Bitcode starts after header.
4559   assert(Buffer.size() >= BWH_HeaderSize &&
4560          "Expected header size to be reserved");
4561   unsigned BCOffset = BWH_HeaderSize;
4562   unsigned BCSize = Buffer.size() - BWH_HeaderSize;
4563 
4564   // Write the magic and version.
4565   unsigned Position = 0;
4566   writeInt32ToBuffer(0x0B17C0DE, Buffer, Position);
4567   writeInt32ToBuffer(0, Buffer, Position); // Version.
4568   writeInt32ToBuffer(BCOffset, Buffer, Position);
4569   writeInt32ToBuffer(BCSize, Buffer, Position);
4570   writeInt32ToBuffer(CPUType, Buffer, Position);
4571 
4572   // If the file is not a multiple of 16 bytes, insert dummy padding.
4573   while (Buffer.size() & 15)
4574     Buffer.push_back(0);
4575 }
4576 
4577 /// Helper to write the header common to all bitcode files.
4578 static void writeBitcodeHeader(BitstreamWriter &Stream) {
4579   // Emit the file header.
4580   Stream.Emit((unsigned)'B', 8);
4581   Stream.Emit((unsigned)'C', 8);
4582   Stream.Emit(0x0, 4);
4583   Stream.Emit(0xC, 4);
4584   Stream.Emit(0xE, 4);
4585   Stream.Emit(0xD, 4);
4586 }
4587 
4588 BitcodeWriter::BitcodeWriter(SmallVectorImpl<char> &Buffer, raw_fd_stream *FS)
4589     : Buffer(Buffer), Stream(new BitstreamWriter(Buffer, FS, FlushThreshold)) {
4590   writeBitcodeHeader(*Stream);
4591 }
4592 
4593 BitcodeWriter::~BitcodeWriter() { assert(WroteStrtab); }
4594 
4595 void BitcodeWriter::writeBlob(unsigned Block, unsigned Record, StringRef Blob) {
4596   Stream->EnterSubblock(Block, 3);
4597 
4598   auto Abbv = std::make_shared<BitCodeAbbrev>();
4599   Abbv->Add(BitCodeAbbrevOp(Record));
4600   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
4601   auto AbbrevNo = Stream->EmitAbbrev(std::move(Abbv));
4602 
4603   Stream->EmitRecordWithBlob(AbbrevNo, ArrayRef<uint64_t>{Record}, Blob);
4604 
4605   Stream->ExitBlock();
4606 }
4607 
4608 void BitcodeWriter::writeSymtab() {
4609   assert(!WroteStrtab && !WroteSymtab);
4610 
4611   // If any module has module-level inline asm, we will require a registered asm
4612   // parser for the target so that we can create an accurate symbol table for
4613   // the module.
4614   for (Module *M : Mods) {
4615     if (M->getModuleInlineAsm().empty())
4616       continue;
4617 
4618     std::string Err;
4619     const Triple TT(M->getTargetTriple());
4620     const Target *T = TargetRegistry::lookupTarget(TT.str(), Err);
4621     if (!T || !T->hasMCAsmParser())
4622       return;
4623   }
4624 
4625   WroteSymtab = true;
4626   SmallVector<char, 0> Symtab;
4627   // The irsymtab::build function may be unable to create a symbol table if the
4628   // module is malformed (e.g. it contains an invalid alias). Writing a symbol
4629   // table is not required for correctness, but we still want to be able to
4630   // write malformed modules to bitcode files, so swallow the error.
4631   if (Error E = irsymtab::build(Mods, Symtab, StrtabBuilder, Alloc)) {
4632     consumeError(std::move(E));
4633     return;
4634   }
4635 
4636   writeBlob(bitc::SYMTAB_BLOCK_ID, bitc::SYMTAB_BLOB,
4637             {Symtab.data(), Symtab.size()});
4638 }
4639 
4640 void BitcodeWriter::writeStrtab() {
4641   assert(!WroteStrtab);
4642 
4643   std::vector<char> Strtab;
4644   StrtabBuilder.finalizeInOrder();
4645   Strtab.resize(StrtabBuilder.getSize());
4646   StrtabBuilder.write((uint8_t *)Strtab.data());
4647 
4648   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB,
4649             {Strtab.data(), Strtab.size()});
4650 
4651   WroteStrtab = true;
4652 }
4653 
4654 void BitcodeWriter::copyStrtab(StringRef Strtab) {
4655   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB, Strtab);
4656   WroteStrtab = true;
4657 }
4658 
4659 void BitcodeWriter::writeModule(const Module &M,
4660                                 bool ShouldPreserveUseListOrder,
4661                                 const ModuleSummaryIndex *Index,
4662                                 bool GenerateHash, ModuleHash *ModHash) {
4663   assert(!WroteStrtab);
4664 
4665   // The Mods vector is used by irsymtab::build, which requires non-const
4666   // Modules in case it needs to materialize metadata. But the bitcode writer
4667   // requires that the module is materialized, so we can cast to non-const here,
4668   // after checking that it is in fact materialized.
4669   assert(M.isMaterialized());
4670   Mods.push_back(const_cast<Module *>(&M));
4671 
4672   ModuleBitcodeWriter ModuleWriter(M, Buffer, StrtabBuilder, *Stream,
4673                                    ShouldPreserveUseListOrder, Index,
4674                                    GenerateHash, ModHash);
4675   ModuleWriter.write();
4676 }
4677 
4678 void BitcodeWriter::writeIndex(
4679     const ModuleSummaryIndex *Index,
4680     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4681   IndexBitcodeWriter IndexWriter(*Stream, StrtabBuilder, *Index,
4682                                  ModuleToSummariesForIndex);
4683   IndexWriter.write();
4684 }
4685 
4686 /// Write the specified module to the specified output stream.
4687 void llvm::WriteBitcodeToFile(const Module &M, raw_ostream &Out,
4688                               bool ShouldPreserveUseListOrder,
4689                               const ModuleSummaryIndex *Index,
4690                               bool GenerateHash, ModuleHash *ModHash) {
4691   SmallVector<char, 0> Buffer;
4692   Buffer.reserve(256*1024);
4693 
4694   // If this is darwin or another generic macho target, reserve space for the
4695   // header.
4696   Triple TT(M.getTargetTriple());
4697   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4698     Buffer.insert(Buffer.begin(), BWH_HeaderSize, 0);
4699 
4700   BitcodeWriter Writer(Buffer, dyn_cast<raw_fd_stream>(&Out));
4701   Writer.writeModule(M, ShouldPreserveUseListOrder, Index, GenerateHash,
4702                      ModHash);
4703   Writer.writeSymtab();
4704   Writer.writeStrtab();
4705 
4706   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4707     emitDarwinBCHeaderAndTrailer(Buffer, TT);
4708 
4709   // Write the generated bitstream to "Out".
4710   if (!Buffer.empty())
4711     Out.write((char *)&Buffer.front(), Buffer.size());
4712 }
4713 
4714 void IndexBitcodeWriter::write() {
4715   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4716 
4717   writeModuleVersion();
4718 
4719   // Write the module paths in the combined index.
4720   writeModStrings();
4721 
4722   // Write the summary combined index records.
4723   writeCombinedGlobalValueSummary();
4724 
4725   Stream.ExitBlock();
4726 }
4727 
4728 // Write the specified module summary index to the given raw output stream,
4729 // where it will be written in a new bitcode block. This is used when
4730 // writing the combined index file for ThinLTO. When writing a subset of the
4731 // index for a distributed backend, provide a \p ModuleToSummariesForIndex map.
4732 void llvm::writeIndexToFile(
4733     const ModuleSummaryIndex &Index, raw_ostream &Out,
4734     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4735   SmallVector<char, 0> Buffer;
4736   Buffer.reserve(256 * 1024);
4737 
4738   BitcodeWriter Writer(Buffer);
4739   Writer.writeIndex(&Index, ModuleToSummariesForIndex);
4740   Writer.writeStrtab();
4741 
4742   Out.write((char *)&Buffer.front(), Buffer.size());
4743 }
4744 
4745 namespace {
4746 
4747 /// Class to manage the bitcode writing for a thin link bitcode file.
4748 class ThinLinkBitcodeWriter : public ModuleBitcodeWriterBase {
4749   /// ModHash is for use in ThinLTO incremental build, generated while writing
4750   /// the module bitcode file.
4751   const ModuleHash *ModHash;
4752 
4753 public:
4754   ThinLinkBitcodeWriter(const Module &M, StringTableBuilder &StrtabBuilder,
4755                         BitstreamWriter &Stream,
4756                         const ModuleSummaryIndex &Index,
4757                         const ModuleHash &ModHash)
4758       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
4759                                 /*ShouldPreserveUseListOrder=*/false, &Index),
4760         ModHash(&ModHash) {}
4761 
4762   void write();
4763 
4764 private:
4765   void writeSimplifiedModuleInfo();
4766 };
4767 
4768 } // end anonymous namespace
4769 
4770 // This function writes a simpilified module info for thin link bitcode file.
4771 // It only contains the source file name along with the name(the offset and
4772 // size in strtab) and linkage for global values. For the global value info
4773 // entry, in order to keep linkage at offset 5, there are three zeros used
4774 // as padding.
4775 void ThinLinkBitcodeWriter::writeSimplifiedModuleInfo() {
4776   SmallVector<unsigned, 64> Vals;
4777   // Emit the module's source file name.
4778   {
4779     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
4780     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
4781     if (Bits == SE_Char6)
4782       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
4783     else if (Bits == SE_Fixed7)
4784       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
4785 
4786     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
4787     auto Abbv = std::make_shared<BitCodeAbbrev>();
4788     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
4789     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4790     Abbv->Add(AbbrevOpToUse);
4791     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4792 
4793     for (const auto P : M.getSourceFileName())
4794       Vals.push_back((unsigned char)P);
4795 
4796     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
4797     Vals.clear();
4798   }
4799 
4800   // Emit the global variable information.
4801   for (const GlobalVariable &GV : M.globals()) {
4802     // GLOBALVAR: [strtab offset, strtab size, 0, 0, 0, linkage]
4803     Vals.push_back(StrtabBuilder.add(GV.getName()));
4804     Vals.push_back(GV.getName().size());
4805     Vals.push_back(0);
4806     Vals.push_back(0);
4807     Vals.push_back(0);
4808     Vals.push_back(getEncodedLinkage(GV));
4809 
4810     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals);
4811     Vals.clear();
4812   }
4813 
4814   // Emit the function proto information.
4815   for (const Function &F : M) {
4816     // FUNCTION:  [strtab offset, strtab size, 0, 0, 0, linkage]
4817     Vals.push_back(StrtabBuilder.add(F.getName()));
4818     Vals.push_back(F.getName().size());
4819     Vals.push_back(0);
4820     Vals.push_back(0);
4821     Vals.push_back(0);
4822     Vals.push_back(getEncodedLinkage(F));
4823 
4824     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals);
4825     Vals.clear();
4826   }
4827 
4828   // Emit the alias information.
4829   for (const GlobalAlias &A : M.aliases()) {
4830     // ALIAS: [strtab offset, strtab size, 0, 0, 0, linkage]
4831     Vals.push_back(StrtabBuilder.add(A.getName()));
4832     Vals.push_back(A.getName().size());
4833     Vals.push_back(0);
4834     Vals.push_back(0);
4835     Vals.push_back(0);
4836     Vals.push_back(getEncodedLinkage(A));
4837 
4838     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals);
4839     Vals.clear();
4840   }
4841 
4842   // Emit the ifunc information.
4843   for (const GlobalIFunc &I : M.ifuncs()) {
4844     // IFUNC: [strtab offset, strtab size, 0, 0, 0, linkage]
4845     Vals.push_back(StrtabBuilder.add(I.getName()));
4846     Vals.push_back(I.getName().size());
4847     Vals.push_back(0);
4848     Vals.push_back(0);
4849     Vals.push_back(0);
4850     Vals.push_back(getEncodedLinkage(I));
4851 
4852     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
4853     Vals.clear();
4854   }
4855 }
4856 
4857 void ThinLinkBitcodeWriter::write() {
4858   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4859 
4860   writeModuleVersion();
4861 
4862   writeSimplifiedModuleInfo();
4863 
4864   writePerModuleGlobalValueSummary();
4865 
4866   // Write module hash.
4867   Stream.EmitRecord(bitc::MODULE_CODE_HASH, ArrayRef<uint32_t>(*ModHash));
4868 
4869   Stream.ExitBlock();
4870 }
4871 
4872 void BitcodeWriter::writeThinLinkBitcode(const Module &M,
4873                                          const ModuleSummaryIndex &Index,
4874                                          const ModuleHash &ModHash) {
4875   assert(!WroteStrtab);
4876 
4877   // The Mods vector is used by irsymtab::build, which requires non-const
4878   // Modules in case it needs to materialize metadata. But the bitcode writer
4879   // requires that the module is materialized, so we can cast to non-const here,
4880   // after checking that it is in fact materialized.
4881   assert(M.isMaterialized());
4882   Mods.push_back(const_cast<Module *>(&M));
4883 
4884   ThinLinkBitcodeWriter ThinLinkWriter(M, StrtabBuilder, *Stream, Index,
4885                                        ModHash);
4886   ThinLinkWriter.write();
4887 }
4888 
4889 // Write the specified thin link bitcode file to the given raw output stream,
4890 // where it will be written in a new bitcode block. This is used when
4891 // writing the per-module index file for ThinLTO.
4892 void llvm::writeThinLinkBitcodeToFile(const Module &M, raw_ostream &Out,
4893                                       const ModuleSummaryIndex &Index,
4894                                       const ModuleHash &ModHash) {
4895   SmallVector<char, 0> Buffer;
4896   Buffer.reserve(256 * 1024);
4897 
4898   BitcodeWriter Writer(Buffer);
4899   Writer.writeThinLinkBitcode(M, Index, ModHash);
4900   Writer.writeSymtab();
4901   Writer.writeStrtab();
4902 
4903   Out.write((char *)&Buffer.front(), Buffer.size());
4904 }
4905 
4906 static const char *getSectionNameForBitcode(const Triple &T) {
4907   switch (T.getObjectFormat()) {
4908   case Triple::MachO:
4909     return "__LLVM,__bitcode";
4910   case Triple::COFF:
4911   case Triple::ELF:
4912   case Triple::Wasm:
4913   case Triple::UnknownObjectFormat:
4914     return ".llvmbc";
4915   case Triple::GOFF:
4916     llvm_unreachable("GOFF is not yet implemented");
4917     break;
4918   case Triple::SPIRV:
4919     llvm_unreachable("SPIRV is not yet implemented");
4920     break;
4921   case Triple::XCOFF:
4922     llvm_unreachable("XCOFF is not yet implemented");
4923     break;
4924   case Triple::DXContainer:
4925     llvm_unreachable("DXContainer is not yet implemented");
4926     break;
4927   }
4928   llvm_unreachable("Unimplemented ObjectFormatType");
4929 }
4930 
4931 static const char *getSectionNameForCommandline(const Triple &T) {
4932   switch (T.getObjectFormat()) {
4933   case Triple::MachO:
4934     return "__LLVM,__cmdline";
4935   case Triple::COFF:
4936   case Triple::ELF:
4937   case Triple::Wasm:
4938   case Triple::UnknownObjectFormat:
4939     return ".llvmcmd";
4940   case Triple::GOFF:
4941     llvm_unreachable("GOFF is not yet implemented");
4942     break;
4943   case Triple::SPIRV:
4944     llvm_unreachable("SPIRV is not yet implemented");
4945     break;
4946   case Triple::XCOFF:
4947     llvm_unreachable("XCOFF is not yet implemented");
4948     break;
4949   case Triple::DXContainer:
4950     llvm_unreachable("DXC is not yet implemented");
4951     break;
4952   }
4953   llvm_unreachable("Unimplemented ObjectFormatType");
4954 }
4955 
4956 void llvm::embedBitcodeInModule(llvm::Module &M, llvm::MemoryBufferRef Buf,
4957                                 bool EmbedBitcode, bool EmbedCmdline,
4958                                 const std::vector<uint8_t> &CmdArgs) {
4959   // Save llvm.compiler.used and remove it.
4960   SmallVector<Constant *, 2> UsedArray;
4961   SmallVector<GlobalValue *, 4> UsedGlobals;
4962   Type *UsedElementType = Type::getInt8Ty(M.getContext())->getPointerTo(0);
4963   GlobalVariable *Used = collectUsedGlobalVariables(M, UsedGlobals, true);
4964   for (auto *GV : UsedGlobals) {
4965     if (GV->getName() != "llvm.embedded.module" &&
4966         GV->getName() != "llvm.cmdline")
4967       UsedArray.push_back(
4968           ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
4969   }
4970   if (Used)
4971     Used->eraseFromParent();
4972 
4973   // Embed the bitcode for the llvm module.
4974   std::string Data;
4975   ArrayRef<uint8_t> ModuleData;
4976   Triple T(M.getTargetTriple());
4977 
4978   if (EmbedBitcode) {
4979     if (Buf.getBufferSize() == 0 ||
4980         !isBitcode((const unsigned char *)Buf.getBufferStart(),
4981                    (const unsigned char *)Buf.getBufferEnd())) {
4982       // If the input is LLVM Assembly, bitcode is produced by serializing
4983       // the module. Use-lists order need to be preserved in this case.
4984       llvm::raw_string_ostream OS(Data);
4985       llvm::WriteBitcodeToFile(M, OS, /* ShouldPreserveUseListOrder */ true);
4986       ModuleData =
4987           ArrayRef<uint8_t>((const uint8_t *)OS.str().data(), OS.str().size());
4988     } else
4989       // If the input is LLVM bitcode, write the input byte stream directly.
4990       ModuleData = ArrayRef<uint8_t>((const uint8_t *)Buf.getBufferStart(),
4991                                      Buf.getBufferSize());
4992   }
4993   llvm::Constant *ModuleConstant =
4994       llvm::ConstantDataArray::get(M.getContext(), ModuleData);
4995   llvm::GlobalVariable *GV = new llvm::GlobalVariable(
4996       M, ModuleConstant->getType(), true, llvm::GlobalValue::PrivateLinkage,
4997       ModuleConstant);
4998   GV->setSection(getSectionNameForBitcode(T));
4999   // Set alignment to 1 to prevent padding between two contributions from input
5000   // sections after linking.
5001   GV->setAlignment(Align(1));
5002   UsedArray.push_back(
5003       ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
5004   if (llvm::GlobalVariable *Old =
5005           M.getGlobalVariable("llvm.embedded.module", true)) {
5006     assert(Old->hasZeroLiveUses() &&
5007            "llvm.embedded.module can only be used once in llvm.compiler.used");
5008     GV->takeName(Old);
5009     Old->eraseFromParent();
5010   } else {
5011     GV->setName("llvm.embedded.module");
5012   }
5013 
5014   // Skip if only bitcode needs to be embedded.
5015   if (EmbedCmdline) {
5016     // Embed command-line options.
5017     ArrayRef<uint8_t> CmdData(const_cast<uint8_t *>(CmdArgs.data()),
5018                               CmdArgs.size());
5019     llvm::Constant *CmdConstant =
5020         llvm::ConstantDataArray::get(M.getContext(), CmdData);
5021     GV = new llvm::GlobalVariable(M, CmdConstant->getType(), true,
5022                                   llvm::GlobalValue::PrivateLinkage,
5023                                   CmdConstant);
5024     GV->setSection(getSectionNameForCommandline(T));
5025     GV->setAlignment(Align(1));
5026     UsedArray.push_back(
5027         ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
5028     if (llvm::GlobalVariable *Old = M.getGlobalVariable("llvm.cmdline", true)) {
5029       assert(Old->hasZeroLiveUses() &&
5030              "llvm.cmdline can only be used once in llvm.compiler.used");
5031       GV->takeName(Old);
5032       Old->eraseFromParent();
5033     } else {
5034       GV->setName("llvm.cmdline");
5035     }
5036   }
5037 
5038   if (UsedArray.empty())
5039     return;
5040 
5041   // Recreate llvm.compiler.used.
5042   ArrayType *ATy = ArrayType::get(UsedElementType, UsedArray.size());
5043   auto *NewUsed = new GlobalVariable(
5044       M, ATy, false, llvm::GlobalValue::AppendingLinkage,
5045       llvm::ConstantArray::get(ATy, UsedArray), "llvm.compiler.used");
5046   NewUsed->setSection("llvm.metadata");
5047 }
5048