xref: /llvm-project/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp (revision 5fc5c7db38672c8962879b6fdce68393181c5e08)
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/SmallString.h"
23 #include "llvm/ADT/SmallVector.h"
24 #include "llvm/ADT/StringMap.h"
25 #include "llvm/ADT/StringRef.h"
26 #include "llvm/ADT/Triple.h"
27 #include "llvm/Bitcode/BitcodeReader.h"
28 #include "llvm/Bitcode/LLVMBitCodes.h"
29 #include "llvm/Bitstream/BitCodes.h"
30 #include "llvm/Bitstream/BitstreamWriter.h"
31 #include "llvm/Config/llvm-config.h"
32 #include "llvm/IR/Attributes.h"
33 #include "llvm/IR/BasicBlock.h"
34 #include "llvm/IR/CallSite.h"
35 #include "llvm/IR/Comdat.h"
36 #include "llvm/IR/Constant.h"
37 #include "llvm/IR/Constants.h"
38 #include "llvm/IR/DebugInfoMetadata.h"
39 #include "llvm/IR/DebugLoc.h"
40 #include "llvm/IR/DerivedTypes.h"
41 #include "llvm/IR/Function.h"
42 #include "llvm/IR/GlobalAlias.h"
43 #include "llvm/IR/GlobalIFunc.h"
44 #include "llvm/IR/GlobalObject.h"
45 #include "llvm/IR/GlobalValue.h"
46 #include "llvm/IR/GlobalVariable.h"
47 #include "llvm/IR/InlineAsm.h"
48 #include "llvm/IR/InstrTypes.h"
49 #include "llvm/IR/Instruction.h"
50 #include "llvm/IR/Instructions.h"
51 #include "llvm/IR/LLVMContext.h"
52 #include "llvm/IR/Metadata.h"
53 #include "llvm/IR/Module.h"
54 #include "llvm/IR/ModuleSummaryIndex.h"
55 #include "llvm/IR/Operator.h"
56 #include "llvm/IR/Type.h"
57 #include "llvm/IR/UseListOrder.h"
58 #include "llvm/IR/Value.h"
59 #include "llvm/IR/ValueSymbolTable.h"
60 #include "llvm/MC/StringTableBuilder.h"
61 #include "llvm/Object/IRSymtab.h"
62 #include "llvm/Support/AtomicOrdering.h"
63 #include "llvm/Support/Casting.h"
64 #include "llvm/Support/CommandLine.h"
65 #include "llvm/Support/Endian.h"
66 #include "llvm/Support/Error.h"
67 #include "llvm/Support/ErrorHandling.h"
68 #include "llvm/Support/MathExtras.h"
69 #include "llvm/Support/SHA1.h"
70 #include "llvm/Support/TargetRegistry.h"
71 #include "llvm/Support/raw_ostream.h"
72 #include <algorithm>
73 #include <cassert>
74 #include <cstddef>
75 #include <cstdint>
76 #include <iterator>
77 #include <map>
78 #include <memory>
79 #include <string>
80 #include <utility>
81 #include <vector>
82 
83 using namespace llvm;
84 
85 static cl::opt<unsigned>
86     IndexThreshold("bitcode-mdindex-threshold", cl::Hidden, cl::init(25),
87                    cl::desc("Number of metadatas above which we emit an index "
88                             "to enable lazy-loading"));
89 
90 static cl::opt<bool> WriteRelBFToSummary(
91     "write-relbf-to-summary", cl::Hidden, cl::init(false),
92     cl::desc("Write relative block frequency to function summary "));
93 
94 extern FunctionSummary::ForceSummaryHotnessType ForceSummaryEdgesCold;
95 
96 namespace {
97 
98 /// These are manifest constants used by the bitcode writer. They do not need to
99 /// be kept in sync with the reader, but need to be consistent within this file.
100 enum {
101   // VALUE_SYMTAB_BLOCK abbrev id's.
102   VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
103   VST_ENTRY_7_ABBREV,
104   VST_ENTRY_6_ABBREV,
105   VST_BBENTRY_6_ABBREV,
106 
107   // CONSTANTS_BLOCK abbrev id's.
108   CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
109   CONSTANTS_INTEGER_ABBREV,
110   CONSTANTS_CE_CAST_Abbrev,
111   CONSTANTS_NULL_Abbrev,
112 
113   // FUNCTION_BLOCK abbrev id's.
114   FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
115   FUNCTION_INST_UNOP_ABBREV,
116   FUNCTION_INST_UNOP_FLAGS_ABBREV,
117   FUNCTION_INST_BINOP_ABBREV,
118   FUNCTION_INST_BINOP_FLAGS_ABBREV,
119   FUNCTION_INST_CAST_ABBREV,
120   FUNCTION_INST_RET_VOID_ABBREV,
121   FUNCTION_INST_RET_VAL_ABBREV,
122   FUNCTION_INST_UNREACHABLE_ABBREV,
123   FUNCTION_INST_GEP_ABBREV,
124 };
125 
126 /// Abstract class to manage the bitcode writing, subclassed for each bitcode
127 /// file type.
128 class BitcodeWriterBase {
129 protected:
130   /// The stream created and owned by the client.
131   BitstreamWriter &Stream;
132 
133   StringTableBuilder &StrtabBuilder;
134 
135 public:
136   /// Constructs a BitcodeWriterBase object that writes to the provided
137   /// \p Stream.
138   BitcodeWriterBase(BitstreamWriter &Stream, StringTableBuilder &StrtabBuilder)
139       : Stream(Stream), StrtabBuilder(StrtabBuilder) {}
140 
141 protected:
142   void writeBitcodeHeader();
143   void writeModuleVersion();
144 };
145 
146 void BitcodeWriterBase::writeModuleVersion() {
147   // VERSION: [version#]
148   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, ArrayRef<uint64_t>{2});
149 }
150 
151 /// Base class to manage the module bitcode writing, currently subclassed for
152 /// ModuleBitcodeWriter and ThinLinkBitcodeWriter.
153 class ModuleBitcodeWriterBase : public BitcodeWriterBase {
154 protected:
155   /// The Module to write to bitcode.
156   const Module &M;
157 
158   /// Enumerates ids for all values in the module.
159   ValueEnumerator VE;
160 
161   /// Optional per-module index to write for ThinLTO.
162   const ModuleSummaryIndex *Index;
163 
164   /// Map that holds the correspondence between GUIDs in the summary index,
165   /// that came from indirect call profiles, and a value id generated by this
166   /// class to use in the VST and summary block records.
167   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
168 
169   /// Tracks the last value id recorded in the GUIDToValueMap.
170   unsigned GlobalValueId;
171 
172   /// Saves the offset of the VSTOffset record that must eventually be
173   /// backpatched with the offset of the actual VST.
174   uint64_t VSTOffsetPlaceholder = 0;
175 
176 public:
177   /// Constructs a ModuleBitcodeWriterBase object for the given Module,
178   /// writing to the provided \p Buffer.
179   ModuleBitcodeWriterBase(const Module &M, StringTableBuilder &StrtabBuilder,
180                           BitstreamWriter &Stream,
181                           bool ShouldPreserveUseListOrder,
182                           const ModuleSummaryIndex *Index)
183       : BitcodeWriterBase(Stream, StrtabBuilder), M(M),
184         VE(M, ShouldPreserveUseListOrder), Index(Index) {
185     // Assign ValueIds to any callee values in the index that came from
186     // indirect call profiles and were recorded as a GUID not a Value*
187     // (which would have been assigned an ID by the ValueEnumerator).
188     // The starting ValueId is just after the number of values in the
189     // ValueEnumerator, so that they can be emitted in the VST.
190     GlobalValueId = VE.getValues().size();
191     if (!Index)
192       return;
193     for (const auto &GUIDSummaryLists : *Index)
194       // Examine all summaries for this GUID.
195       for (auto &Summary : GUIDSummaryLists.second.SummaryList)
196         if (auto FS = dyn_cast<FunctionSummary>(Summary.get()))
197           // For each call in the function summary, see if the call
198           // is to a GUID (which means it is for an indirect call,
199           // otherwise we would have a Value for it). If so, synthesize
200           // a value id.
201           for (auto &CallEdge : FS->calls())
202             if (!CallEdge.first.haveGVs() || !CallEdge.first.getValue())
203               assignValueId(CallEdge.first.getGUID());
204   }
205 
206 protected:
207   void writePerModuleGlobalValueSummary();
208 
209 private:
210   void writePerModuleFunctionSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
211                                            GlobalValueSummary *Summary,
212                                            unsigned ValueID,
213                                            unsigned FSCallsAbbrev,
214                                            unsigned FSCallsProfileAbbrev,
215                                            const Function &F);
216   void writeModuleLevelReferences(const GlobalVariable &V,
217                                   SmallVector<uint64_t, 64> &NameVals,
218                                   unsigned FSModRefsAbbrev,
219                                   unsigned FSModVTableRefsAbbrev);
220 
221   void assignValueId(GlobalValue::GUID ValGUID) {
222     GUIDToValueIdMap[ValGUID] = ++GlobalValueId;
223   }
224 
225   unsigned getValueId(GlobalValue::GUID ValGUID) {
226     const auto &VMI = GUIDToValueIdMap.find(ValGUID);
227     // Expect that any GUID value had a value Id assigned by an
228     // earlier call to assignValueId.
229     assert(VMI != GUIDToValueIdMap.end() &&
230            "GUID does not have assigned value Id");
231     return VMI->second;
232   }
233 
234   // Helper to get the valueId for the type of value recorded in VI.
235   unsigned getValueId(ValueInfo VI) {
236     if (!VI.haveGVs() || !VI.getValue())
237       return getValueId(VI.getGUID());
238     return VE.getValueID(VI.getValue());
239   }
240 
241   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
242 };
243 
244 /// Class to manage the bitcode writing for a module.
245 class ModuleBitcodeWriter : public ModuleBitcodeWriterBase {
246   /// Pointer to the buffer allocated by caller for bitcode writing.
247   const SmallVectorImpl<char> &Buffer;
248 
249   /// True if a module hash record should be written.
250   bool GenerateHash;
251 
252   /// If non-null, when GenerateHash is true, the resulting hash is written
253   /// into ModHash.
254   ModuleHash *ModHash;
255 
256   SHA1 Hasher;
257 
258   /// The start bit of the identification block.
259   uint64_t BitcodeStartBit;
260 
261 public:
262   /// Constructs a ModuleBitcodeWriter object for the given Module,
263   /// writing to the provided \p Buffer.
264   ModuleBitcodeWriter(const Module &M, SmallVectorImpl<char> &Buffer,
265                       StringTableBuilder &StrtabBuilder,
266                       BitstreamWriter &Stream, bool ShouldPreserveUseListOrder,
267                       const ModuleSummaryIndex *Index, bool GenerateHash,
268                       ModuleHash *ModHash = nullptr)
269       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
270                                 ShouldPreserveUseListOrder, Index),
271         Buffer(Buffer), GenerateHash(GenerateHash), ModHash(ModHash),
272         BitcodeStartBit(Stream.GetCurrentBitNo()) {}
273 
274   /// Emit the current module to the bitstream.
275   void write();
276 
277 private:
278   uint64_t bitcodeStartBit() { return BitcodeStartBit; }
279 
280   size_t addToStrtab(StringRef Str);
281 
282   void writeAttributeGroupTable();
283   void writeAttributeTable();
284   void writeTypeTable();
285   void writeComdats();
286   void writeValueSymbolTableForwardDecl();
287   void writeModuleInfo();
288   void writeValueAsMetadata(const ValueAsMetadata *MD,
289                             SmallVectorImpl<uint64_t> &Record);
290   void writeMDTuple(const MDTuple *N, SmallVectorImpl<uint64_t> &Record,
291                     unsigned Abbrev);
292   unsigned createDILocationAbbrev();
293   void writeDILocation(const DILocation *N, SmallVectorImpl<uint64_t> &Record,
294                        unsigned &Abbrev);
295   unsigned createGenericDINodeAbbrev();
296   void writeGenericDINode(const GenericDINode *N,
297                           SmallVectorImpl<uint64_t> &Record, unsigned &Abbrev);
298   void writeDISubrange(const DISubrange *N, SmallVectorImpl<uint64_t> &Record,
299                        unsigned Abbrev);
300   void writeDIEnumerator(const DIEnumerator *N,
301                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
302   void writeDIBasicType(const DIBasicType *N, SmallVectorImpl<uint64_t> &Record,
303                         unsigned Abbrev);
304   void writeDIDerivedType(const DIDerivedType *N,
305                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
306   void writeDICompositeType(const DICompositeType *N,
307                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
308   void writeDISubroutineType(const DISubroutineType *N,
309                              SmallVectorImpl<uint64_t> &Record,
310                              unsigned Abbrev);
311   void writeDIFile(const DIFile *N, SmallVectorImpl<uint64_t> &Record,
312                    unsigned Abbrev);
313   void writeDICompileUnit(const DICompileUnit *N,
314                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
315   void writeDISubprogram(const DISubprogram *N,
316                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
317   void writeDILexicalBlock(const DILexicalBlock *N,
318                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
319   void writeDILexicalBlockFile(const DILexicalBlockFile *N,
320                                SmallVectorImpl<uint64_t> &Record,
321                                unsigned Abbrev);
322   void writeDICommonBlock(const DICommonBlock *N,
323                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
324   void writeDINamespace(const DINamespace *N, SmallVectorImpl<uint64_t> &Record,
325                         unsigned Abbrev);
326   void writeDIMacro(const DIMacro *N, SmallVectorImpl<uint64_t> &Record,
327                     unsigned Abbrev);
328   void writeDIMacroFile(const DIMacroFile *N, SmallVectorImpl<uint64_t> &Record,
329                         unsigned Abbrev);
330   void writeDIModule(const DIModule *N, SmallVectorImpl<uint64_t> &Record,
331                      unsigned Abbrev);
332   void writeDITemplateTypeParameter(const DITemplateTypeParameter *N,
333                                     SmallVectorImpl<uint64_t> &Record,
334                                     unsigned Abbrev);
335   void writeDITemplateValueParameter(const DITemplateValueParameter *N,
336                                      SmallVectorImpl<uint64_t> &Record,
337                                      unsigned Abbrev);
338   void writeDIGlobalVariable(const DIGlobalVariable *N,
339                              SmallVectorImpl<uint64_t> &Record,
340                              unsigned Abbrev);
341   void writeDILocalVariable(const DILocalVariable *N,
342                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
343   void writeDILabel(const DILabel *N,
344                     SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
345   void writeDIExpression(const DIExpression *N,
346                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
347   void writeDIGlobalVariableExpression(const DIGlobalVariableExpression *N,
348                                        SmallVectorImpl<uint64_t> &Record,
349                                        unsigned Abbrev);
350   void writeDIObjCProperty(const DIObjCProperty *N,
351                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
352   void writeDIImportedEntity(const DIImportedEntity *N,
353                              SmallVectorImpl<uint64_t> &Record,
354                              unsigned Abbrev);
355   unsigned createNamedMetadataAbbrev();
356   void writeNamedMetadata(SmallVectorImpl<uint64_t> &Record);
357   unsigned createMetadataStringsAbbrev();
358   void writeMetadataStrings(ArrayRef<const Metadata *> Strings,
359                             SmallVectorImpl<uint64_t> &Record);
360   void writeMetadataRecords(ArrayRef<const Metadata *> MDs,
361                             SmallVectorImpl<uint64_t> &Record,
362                             std::vector<unsigned> *MDAbbrevs = nullptr,
363                             std::vector<uint64_t> *IndexPos = nullptr);
364   void writeModuleMetadata();
365   void writeFunctionMetadata(const Function &F);
366   void writeFunctionMetadataAttachment(const Function &F);
367   void writeGlobalVariableMetadataAttachment(const GlobalVariable &GV);
368   void pushGlobalMetadataAttachment(SmallVectorImpl<uint64_t> &Record,
369                                     const GlobalObject &GO);
370   void writeModuleMetadataKinds();
371   void writeOperandBundleTags();
372   void writeSyncScopeNames();
373   void writeConstants(unsigned FirstVal, unsigned LastVal, bool isGlobal);
374   void writeModuleConstants();
375   bool pushValueAndType(const Value *V, unsigned InstID,
376                         SmallVectorImpl<unsigned> &Vals);
377   void writeOperandBundles(ImmutableCallSite CS, unsigned InstID);
378   void pushValue(const Value *V, unsigned InstID,
379                  SmallVectorImpl<unsigned> &Vals);
380   void pushValueSigned(const Value *V, unsigned InstID,
381                        SmallVectorImpl<uint64_t> &Vals);
382   void writeInstruction(const Instruction &I, unsigned InstID,
383                         SmallVectorImpl<unsigned> &Vals);
384   void writeFunctionLevelValueSymbolTable(const ValueSymbolTable &VST);
385   void writeGlobalValueSymbolTable(
386       DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
387   void writeUseList(UseListOrder &&Order);
388   void writeUseListBlock(const Function *F);
389   void
390   writeFunction(const Function &F,
391                 DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
392   void writeBlockInfo();
393   void writeModuleHash(size_t BlockStartPos);
394 
395   unsigned getEncodedSyncScopeID(SyncScope::ID SSID) {
396     return unsigned(SSID);
397   }
398 };
399 
400 /// Class to manage the bitcode writing for a combined index.
401 class IndexBitcodeWriter : public BitcodeWriterBase {
402   /// The combined index to write to bitcode.
403   const ModuleSummaryIndex &Index;
404 
405   /// When writing a subset of the index for distributed backends, client
406   /// provides a map of modules to the corresponding GUIDs/summaries to write.
407   const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex;
408 
409   /// Map that holds the correspondence between the GUID used in the combined
410   /// index and a value id generated by this class to use in references.
411   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
412 
413   /// Tracks the last value id recorded in the GUIDToValueMap.
414   unsigned GlobalValueId = 0;
415 
416 public:
417   /// Constructs a IndexBitcodeWriter object for the given combined index,
418   /// writing to the provided \p Buffer. When writing a subset of the index
419   /// for a distributed backend, provide a \p ModuleToSummariesForIndex map.
420   IndexBitcodeWriter(BitstreamWriter &Stream, StringTableBuilder &StrtabBuilder,
421                      const ModuleSummaryIndex &Index,
422                      const std::map<std::string, GVSummaryMapTy>
423                          *ModuleToSummariesForIndex = nullptr)
424       : BitcodeWriterBase(Stream, StrtabBuilder), Index(Index),
425         ModuleToSummariesForIndex(ModuleToSummariesForIndex) {
426     // Assign unique value ids to all summaries to be written, for use
427     // in writing out the call graph edges. Save the mapping from GUID
428     // to the new global value id to use when writing those edges, which
429     // are currently saved in the index in terms of GUID.
430     forEachSummary([&](GVInfo I, bool) {
431       GUIDToValueIdMap[I.first] = ++GlobalValueId;
432     });
433   }
434 
435   /// The below iterator returns the GUID and associated summary.
436   using GVInfo = std::pair<GlobalValue::GUID, GlobalValueSummary *>;
437 
438   /// Calls the callback for each value GUID and summary to be written to
439   /// bitcode. This hides the details of whether they are being pulled from the
440   /// entire index or just those in a provided ModuleToSummariesForIndex map.
441   template<typename Functor>
442   void forEachSummary(Functor Callback) {
443     if (ModuleToSummariesForIndex) {
444       for (auto &M : *ModuleToSummariesForIndex)
445         for (auto &Summary : M.second) {
446           Callback(Summary, false);
447           // Ensure aliasee is handled, e.g. for assigning a valueId,
448           // even if we are not importing the aliasee directly (the
449           // imported alias will contain a copy of aliasee).
450           if (auto *AS = dyn_cast<AliasSummary>(Summary.getSecond()))
451             Callback({AS->getAliaseeGUID(), &AS->getAliasee()}, true);
452         }
453     } else {
454       for (auto &Summaries : Index)
455         for (auto &Summary : Summaries.second.SummaryList)
456           Callback({Summaries.first, Summary.get()}, false);
457     }
458   }
459 
460   /// Calls the callback for each entry in the modulePaths StringMap that
461   /// should be written to the module path string table. This hides the details
462   /// of whether they are being pulled from the entire index or just those in a
463   /// provided ModuleToSummariesForIndex map.
464   template <typename Functor> void forEachModule(Functor Callback) {
465     if (ModuleToSummariesForIndex) {
466       for (const auto &M : *ModuleToSummariesForIndex) {
467         const auto &MPI = Index.modulePaths().find(M.first);
468         if (MPI == Index.modulePaths().end()) {
469           // This should only happen if the bitcode file was empty, in which
470           // case we shouldn't be importing (the ModuleToSummariesForIndex
471           // would only include the module we are writing and index for).
472           assert(ModuleToSummariesForIndex->size() == 1);
473           continue;
474         }
475         Callback(*MPI);
476       }
477     } else {
478       for (const auto &MPSE : Index.modulePaths())
479         Callback(MPSE);
480     }
481   }
482 
483   /// Main entry point for writing a combined index to bitcode.
484   void write();
485 
486 private:
487   void writeModStrings();
488   void writeCombinedGlobalValueSummary();
489 
490   Optional<unsigned> getValueId(GlobalValue::GUID ValGUID) {
491     auto VMI = GUIDToValueIdMap.find(ValGUID);
492     if (VMI == GUIDToValueIdMap.end())
493       return None;
494     return VMI->second;
495   }
496 
497   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
498 };
499 
500 } // end anonymous namespace
501 
502 static unsigned getEncodedCastOpcode(unsigned Opcode) {
503   switch (Opcode) {
504   default: llvm_unreachable("Unknown cast instruction!");
505   case Instruction::Trunc   : return bitc::CAST_TRUNC;
506   case Instruction::ZExt    : return bitc::CAST_ZEXT;
507   case Instruction::SExt    : return bitc::CAST_SEXT;
508   case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
509   case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
510   case Instruction::UIToFP  : return bitc::CAST_UITOFP;
511   case Instruction::SIToFP  : return bitc::CAST_SITOFP;
512   case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
513   case Instruction::FPExt   : return bitc::CAST_FPEXT;
514   case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
515   case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
516   case Instruction::BitCast : return bitc::CAST_BITCAST;
517   case Instruction::AddrSpaceCast: return bitc::CAST_ADDRSPACECAST;
518   }
519 }
520 
521 static unsigned getEncodedUnaryOpcode(unsigned Opcode) {
522   switch (Opcode) {
523   default: llvm_unreachable("Unknown binary instruction!");
524   case Instruction::FNeg: return bitc::UNOP_FNEG;
525   }
526 }
527 
528 static unsigned getEncodedBinaryOpcode(unsigned Opcode) {
529   switch (Opcode) {
530   default: llvm_unreachable("Unknown binary instruction!");
531   case Instruction::Add:
532   case Instruction::FAdd: return bitc::BINOP_ADD;
533   case Instruction::Sub:
534   case Instruction::FSub: return bitc::BINOP_SUB;
535   case Instruction::Mul:
536   case Instruction::FMul: return bitc::BINOP_MUL;
537   case Instruction::UDiv: return bitc::BINOP_UDIV;
538   case Instruction::FDiv:
539   case Instruction::SDiv: return bitc::BINOP_SDIV;
540   case Instruction::URem: return bitc::BINOP_UREM;
541   case Instruction::FRem:
542   case Instruction::SRem: return bitc::BINOP_SREM;
543   case Instruction::Shl:  return bitc::BINOP_SHL;
544   case Instruction::LShr: return bitc::BINOP_LSHR;
545   case Instruction::AShr: return bitc::BINOP_ASHR;
546   case Instruction::And:  return bitc::BINOP_AND;
547   case Instruction::Or:   return bitc::BINOP_OR;
548   case Instruction::Xor:  return bitc::BINOP_XOR;
549   }
550 }
551 
552 static unsigned getEncodedRMWOperation(AtomicRMWInst::BinOp Op) {
553   switch (Op) {
554   default: llvm_unreachable("Unknown RMW operation!");
555   case AtomicRMWInst::Xchg: return bitc::RMW_XCHG;
556   case AtomicRMWInst::Add: return bitc::RMW_ADD;
557   case AtomicRMWInst::Sub: return bitc::RMW_SUB;
558   case AtomicRMWInst::And: return bitc::RMW_AND;
559   case AtomicRMWInst::Nand: return bitc::RMW_NAND;
560   case AtomicRMWInst::Or: return bitc::RMW_OR;
561   case AtomicRMWInst::Xor: return bitc::RMW_XOR;
562   case AtomicRMWInst::Max: return bitc::RMW_MAX;
563   case AtomicRMWInst::Min: return bitc::RMW_MIN;
564   case AtomicRMWInst::UMax: return bitc::RMW_UMAX;
565   case AtomicRMWInst::UMin: return bitc::RMW_UMIN;
566   case AtomicRMWInst::FAdd: return bitc::RMW_FADD;
567   case AtomicRMWInst::FSub: return bitc::RMW_FSUB;
568   }
569 }
570 
571 static unsigned getEncodedOrdering(AtomicOrdering Ordering) {
572   switch (Ordering) {
573   case AtomicOrdering::NotAtomic: return bitc::ORDERING_NOTATOMIC;
574   case AtomicOrdering::Unordered: return bitc::ORDERING_UNORDERED;
575   case AtomicOrdering::Monotonic: return bitc::ORDERING_MONOTONIC;
576   case AtomicOrdering::Acquire: return bitc::ORDERING_ACQUIRE;
577   case AtomicOrdering::Release: return bitc::ORDERING_RELEASE;
578   case AtomicOrdering::AcquireRelease: return bitc::ORDERING_ACQREL;
579   case AtomicOrdering::SequentiallyConsistent: return bitc::ORDERING_SEQCST;
580   }
581   llvm_unreachable("Invalid ordering");
582 }
583 
584 static void writeStringRecord(BitstreamWriter &Stream, unsigned Code,
585                               StringRef Str, unsigned AbbrevToUse) {
586   SmallVector<unsigned, 64> Vals;
587 
588   // Code: [strchar x N]
589   for (unsigned i = 0, e = Str.size(); i != e; ++i) {
590     if (AbbrevToUse && !BitCodeAbbrevOp::isChar6(Str[i]))
591       AbbrevToUse = 0;
592     Vals.push_back(Str[i]);
593   }
594 
595   // Emit the finished record.
596   Stream.EmitRecord(Code, Vals, AbbrevToUse);
597 }
598 
599 static uint64_t getAttrKindEncoding(Attribute::AttrKind Kind) {
600   switch (Kind) {
601   case Attribute::Alignment:
602     return bitc::ATTR_KIND_ALIGNMENT;
603   case Attribute::AllocSize:
604     return bitc::ATTR_KIND_ALLOC_SIZE;
605   case Attribute::AlwaysInline:
606     return bitc::ATTR_KIND_ALWAYS_INLINE;
607   case Attribute::ArgMemOnly:
608     return bitc::ATTR_KIND_ARGMEMONLY;
609   case Attribute::Builtin:
610     return bitc::ATTR_KIND_BUILTIN;
611   case Attribute::ByVal:
612     return bitc::ATTR_KIND_BY_VAL;
613   case Attribute::Convergent:
614     return bitc::ATTR_KIND_CONVERGENT;
615   case Attribute::InAlloca:
616     return bitc::ATTR_KIND_IN_ALLOCA;
617   case Attribute::Cold:
618     return bitc::ATTR_KIND_COLD;
619   case Attribute::InaccessibleMemOnly:
620     return bitc::ATTR_KIND_INACCESSIBLEMEM_ONLY;
621   case Attribute::InaccessibleMemOrArgMemOnly:
622     return bitc::ATTR_KIND_INACCESSIBLEMEM_OR_ARGMEMONLY;
623   case Attribute::InlineHint:
624     return bitc::ATTR_KIND_INLINE_HINT;
625   case Attribute::InReg:
626     return bitc::ATTR_KIND_IN_REG;
627   case Attribute::JumpTable:
628     return bitc::ATTR_KIND_JUMP_TABLE;
629   case Attribute::MinSize:
630     return bitc::ATTR_KIND_MIN_SIZE;
631   case Attribute::Naked:
632     return bitc::ATTR_KIND_NAKED;
633   case Attribute::Nest:
634     return bitc::ATTR_KIND_NEST;
635   case Attribute::NoAlias:
636     return bitc::ATTR_KIND_NO_ALIAS;
637   case Attribute::NoBuiltin:
638     return bitc::ATTR_KIND_NO_BUILTIN;
639   case Attribute::NoCapture:
640     return bitc::ATTR_KIND_NO_CAPTURE;
641   case Attribute::NoDuplicate:
642     return bitc::ATTR_KIND_NO_DUPLICATE;
643   case Attribute::NoFree:
644     return bitc::ATTR_KIND_NOFREE;
645   case Attribute::NoImplicitFloat:
646     return bitc::ATTR_KIND_NO_IMPLICIT_FLOAT;
647   case Attribute::NoInline:
648     return bitc::ATTR_KIND_NO_INLINE;
649   case Attribute::NoRecurse:
650     return bitc::ATTR_KIND_NO_RECURSE;
651   case Attribute::NonLazyBind:
652     return bitc::ATTR_KIND_NON_LAZY_BIND;
653   case Attribute::NonNull:
654     return bitc::ATTR_KIND_NON_NULL;
655   case Attribute::Dereferenceable:
656     return bitc::ATTR_KIND_DEREFERENCEABLE;
657   case Attribute::DereferenceableOrNull:
658     return bitc::ATTR_KIND_DEREFERENCEABLE_OR_NULL;
659   case Attribute::NoRedZone:
660     return bitc::ATTR_KIND_NO_RED_ZONE;
661   case Attribute::NoReturn:
662     return bitc::ATTR_KIND_NO_RETURN;
663   case Attribute::NoSync:
664     return bitc::ATTR_KIND_NOSYNC;
665   case Attribute::NoCfCheck:
666     return bitc::ATTR_KIND_NOCF_CHECK;
667   case Attribute::NoUnwind:
668     return bitc::ATTR_KIND_NO_UNWIND;
669   case Attribute::OptForFuzzing:
670     return bitc::ATTR_KIND_OPT_FOR_FUZZING;
671   case Attribute::OptimizeForSize:
672     return bitc::ATTR_KIND_OPTIMIZE_FOR_SIZE;
673   case Attribute::OptimizeNone:
674     return bitc::ATTR_KIND_OPTIMIZE_NONE;
675   case Attribute::ReadNone:
676     return bitc::ATTR_KIND_READ_NONE;
677   case Attribute::ReadOnly:
678     return bitc::ATTR_KIND_READ_ONLY;
679   case Attribute::Returned:
680     return bitc::ATTR_KIND_RETURNED;
681   case Attribute::ReturnsTwice:
682     return bitc::ATTR_KIND_RETURNS_TWICE;
683   case Attribute::SExt:
684     return bitc::ATTR_KIND_S_EXT;
685   case Attribute::Speculatable:
686     return bitc::ATTR_KIND_SPECULATABLE;
687   case Attribute::StackAlignment:
688     return bitc::ATTR_KIND_STACK_ALIGNMENT;
689   case Attribute::StackProtect:
690     return bitc::ATTR_KIND_STACK_PROTECT;
691   case Attribute::StackProtectReq:
692     return bitc::ATTR_KIND_STACK_PROTECT_REQ;
693   case Attribute::StackProtectStrong:
694     return bitc::ATTR_KIND_STACK_PROTECT_STRONG;
695   case Attribute::SafeStack:
696     return bitc::ATTR_KIND_SAFESTACK;
697   case Attribute::ShadowCallStack:
698     return bitc::ATTR_KIND_SHADOWCALLSTACK;
699   case Attribute::StrictFP:
700     return bitc::ATTR_KIND_STRICT_FP;
701   case Attribute::StructRet:
702     return bitc::ATTR_KIND_STRUCT_RET;
703   case Attribute::SanitizeAddress:
704     return bitc::ATTR_KIND_SANITIZE_ADDRESS;
705   case Attribute::SanitizeHWAddress:
706     return bitc::ATTR_KIND_SANITIZE_HWADDRESS;
707   case Attribute::SanitizeThread:
708     return bitc::ATTR_KIND_SANITIZE_THREAD;
709   case Attribute::SanitizeMemory:
710     return bitc::ATTR_KIND_SANITIZE_MEMORY;
711   case Attribute::SpeculativeLoadHardening:
712     return bitc::ATTR_KIND_SPECULATIVE_LOAD_HARDENING;
713   case Attribute::SwiftError:
714     return bitc::ATTR_KIND_SWIFT_ERROR;
715   case Attribute::SwiftSelf:
716     return bitc::ATTR_KIND_SWIFT_SELF;
717   case Attribute::UWTable:
718     return bitc::ATTR_KIND_UW_TABLE;
719   case Attribute::WillReturn:
720     return bitc::ATTR_KIND_WILLRETURN;
721   case Attribute::WriteOnly:
722     return bitc::ATTR_KIND_WRITEONLY;
723   case Attribute::ZExt:
724     return bitc::ATTR_KIND_Z_EXT;
725   case Attribute::ImmArg:
726     return bitc::ATTR_KIND_IMMARG;
727   case Attribute::SanitizeMemTag:
728     return bitc::ATTR_KIND_SANITIZE_MEMTAG;
729   case Attribute::EndAttrKinds:
730     llvm_unreachable("Can not encode end-attribute kinds marker.");
731   case Attribute::None:
732     llvm_unreachable("Can not encode none-attribute.");
733   }
734 
735   llvm_unreachable("Trying to encode unknown attribute");
736 }
737 
738 void ModuleBitcodeWriter::writeAttributeGroupTable() {
739   const std::vector<ValueEnumerator::IndexAndAttrSet> &AttrGrps =
740       VE.getAttributeGroups();
741   if (AttrGrps.empty()) return;
742 
743   Stream.EnterSubblock(bitc::PARAMATTR_GROUP_BLOCK_ID, 3);
744 
745   SmallVector<uint64_t, 64> Record;
746   for (ValueEnumerator::IndexAndAttrSet Pair : AttrGrps) {
747     unsigned AttrListIndex = Pair.first;
748     AttributeSet AS = Pair.second;
749     Record.push_back(VE.getAttributeGroupID(Pair));
750     Record.push_back(AttrListIndex);
751 
752     for (Attribute Attr : AS) {
753       if (Attr.isEnumAttribute()) {
754         Record.push_back(0);
755         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
756       } else if (Attr.isIntAttribute()) {
757         Record.push_back(1);
758         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
759         Record.push_back(Attr.getValueAsInt());
760       } else if (Attr.isStringAttribute()) {
761         StringRef Kind = Attr.getKindAsString();
762         StringRef Val = Attr.getValueAsString();
763 
764         Record.push_back(Val.empty() ? 3 : 4);
765         Record.append(Kind.begin(), Kind.end());
766         Record.push_back(0);
767         if (!Val.empty()) {
768           Record.append(Val.begin(), Val.end());
769           Record.push_back(0);
770         }
771       } else {
772         assert(Attr.isTypeAttribute());
773         Type *Ty = Attr.getValueAsType();
774         Record.push_back(Ty ? 6 : 5);
775         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
776         if (Ty)
777           Record.push_back(VE.getTypeID(Attr.getValueAsType()));
778       }
779     }
780 
781     Stream.EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
782     Record.clear();
783   }
784 
785   Stream.ExitBlock();
786 }
787 
788 void ModuleBitcodeWriter::writeAttributeTable() {
789   const std::vector<AttributeList> &Attrs = VE.getAttributeLists();
790   if (Attrs.empty()) return;
791 
792   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
793 
794   SmallVector<uint64_t, 64> Record;
795   for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
796     AttributeList AL = Attrs[i];
797     for (unsigned i = AL.index_begin(), e = AL.index_end(); i != e; ++i) {
798       AttributeSet AS = AL.getAttributes(i);
799       if (AS.hasAttributes())
800         Record.push_back(VE.getAttributeGroupID({i, AS}));
801     }
802 
803     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
804     Record.clear();
805   }
806 
807   Stream.ExitBlock();
808 }
809 
810 /// WriteTypeTable - Write out the type table for a module.
811 void ModuleBitcodeWriter::writeTypeTable() {
812   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
813 
814   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
815   SmallVector<uint64_t, 64> TypeVals;
816 
817   uint64_t NumBits = VE.computeBitsRequiredForTypeIndicies();
818 
819   // Abbrev for TYPE_CODE_POINTER.
820   auto Abbv = std::make_shared<BitCodeAbbrev>();
821   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
822   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
823   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
824   unsigned PtrAbbrev = Stream.EmitAbbrev(std::move(Abbv));
825 
826   // Abbrev for TYPE_CODE_FUNCTION.
827   Abbv = std::make_shared<BitCodeAbbrev>();
828   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
829   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
830   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
831   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
832   unsigned FunctionAbbrev = Stream.EmitAbbrev(std::move(Abbv));
833 
834   // Abbrev for TYPE_CODE_STRUCT_ANON.
835   Abbv = std::make_shared<BitCodeAbbrev>();
836   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
837   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
838   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
839   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
840   unsigned StructAnonAbbrev = Stream.EmitAbbrev(std::move(Abbv));
841 
842   // Abbrev for TYPE_CODE_STRUCT_NAME.
843   Abbv = std::make_shared<BitCodeAbbrev>();
844   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
845   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
846   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
847   unsigned StructNameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
848 
849   // Abbrev for TYPE_CODE_STRUCT_NAMED.
850   Abbv = std::make_shared<BitCodeAbbrev>();
851   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
852   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
853   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
854   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
855   unsigned StructNamedAbbrev = Stream.EmitAbbrev(std::move(Abbv));
856 
857   // Abbrev for TYPE_CODE_ARRAY.
858   Abbv = std::make_shared<BitCodeAbbrev>();
859   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
860   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
861   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
862   unsigned ArrayAbbrev = Stream.EmitAbbrev(std::move(Abbv));
863 
864   // Emit an entry count so the reader can reserve space.
865   TypeVals.push_back(TypeList.size());
866   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
867   TypeVals.clear();
868 
869   // Loop over all of the types, emitting each in turn.
870   for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
871     Type *T = TypeList[i];
872     int AbbrevToUse = 0;
873     unsigned Code = 0;
874 
875     switch (T->getTypeID()) {
876     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;      break;
877     case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;      break;
878     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;     break;
879     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE;    break;
880     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80;  break;
881     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128;     break;
882     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
883     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;     break;
884     case Type::MetadataTyID:  Code = bitc::TYPE_CODE_METADATA;  break;
885     case Type::X86_MMXTyID:   Code = bitc::TYPE_CODE_X86_MMX;   break;
886     case Type::TokenTyID:     Code = bitc::TYPE_CODE_TOKEN;     break;
887     case Type::IntegerTyID:
888       // INTEGER: [width]
889       Code = bitc::TYPE_CODE_INTEGER;
890       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
891       break;
892     case Type::PointerTyID: {
893       PointerType *PTy = cast<PointerType>(T);
894       // POINTER: [pointee type, address space]
895       Code = bitc::TYPE_CODE_POINTER;
896       TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
897       unsigned AddressSpace = PTy->getAddressSpace();
898       TypeVals.push_back(AddressSpace);
899       if (AddressSpace == 0) AbbrevToUse = PtrAbbrev;
900       break;
901     }
902     case Type::FunctionTyID: {
903       FunctionType *FT = cast<FunctionType>(T);
904       // FUNCTION: [isvararg, retty, paramty x N]
905       Code = bitc::TYPE_CODE_FUNCTION;
906       TypeVals.push_back(FT->isVarArg());
907       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
908       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
909         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
910       AbbrevToUse = FunctionAbbrev;
911       break;
912     }
913     case Type::StructTyID: {
914       StructType *ST = cast<StructType>(T);
915       // STRUCT: [ispacked, eltty x N]
916       TypeVals.push_back(ST->isPacked());
917       // Output all of the element types.
918       for (StructType::element_iterator I = ST->element_begin(),
919            E = ST->element_end(); I != E; ++I)
920         TypeVals.push_back(VE.getTypeID(*I));
921 
922       if (ST->isLiteral()) {
923         Code = bitc::TYPE_CODE_STRUCT_ANON;
924         AbbrevToUse = StructAnonAbbrev;
925       } else {
926         if (ST->isOpaque()) {
927           Code = bitc::TYPE_CODE_OPAQUE;
928         } else {
929           Code = bitc::TYPE_CODE_STRUCT_NAMED;
930           AbbrevToUse = StructNamedAbbrev;
931         }
932 
933         // Emit the name if it is present.
934         if (!ST->getName().empty())
935           writeStringRecord(Stream, bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
936                             StructNameAbbrev);
937       }
938       break;
939     }
940     case Type::ArrayTyID: {
941       ArrayType *AT = cast<ArrayType>(T);
942       // ARRAY: [numelts, eltty]
943       Code = bitc::TYPE_CODE_ARRAY;
944       TypeVals.push_back(AT->getNumElements());
945       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
946       AbbrevToUse = ArrayAbbrev;
947       break;
948     }
949     case Type::VectorTyID: {
950       VectorType *VT = cast<VectorType>(T);
951       // VECTOR [numelts, eltty] or
952       //        [numelts, eltty, scalable]
953       Code = bitc::TYPE_CODE_VECTOR;
954       TypeVals.push_back(VT->getNumElements());
955       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
956       if (VT->isScalable())
957         TypeVals.push_back(VT->isScalable());
958       break;
959     }
960     }
961 
962     // Emit the finished record.
963     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
964     TypeVals.clear();
965   }
966 
967   Stream.ExitBlock();
968 }
969 
970 static unsigned getEncodedLinkage(const GlobalValue::LinkageTypes Linkage) {
971   switch (Linkage) {
972   case GlobalValue::ExternalLinkage:
973     return 0;
974   case GlobalValue::WeakAnyLinkage:
975     return 16;
976   case GlobalValue::AppendingLinkage:
977     return 2;
978   case GlobalValue::InternalLinkage:
979     return 3;
980   case GlobalValue::LinkOnceAnyLinkage:
981     return 18;
982   case GlobalValue::ExternalWeakLinkage:
983     return 7;
984   case GlobalValue::CommonLinkage:
985     return 8;
986   case GlobalValue::PrivateLinkage:
987     return 9;
988   case GlobalValue::WeakODRLinkage:
989     return 17;
990   case GlobalValue::LinkOnceODRLinkage:
991     return 19;
992   case GlobalValue::AvailableExternallyLinkage:
993     return 12;
994   }
995   llvm_unreachable("Invalid linkage");
996 }
997 
998 static unsigned getEncodedLinkage(const GlobalValue &GV) {
999   return getEncodedLinkage(GV.getLinkage());
1000 }
1001 
1002 static uint64_t getEncodedFFlags(FunctionSummary::FFlags Flags) {
1003   uint64_t RawFlags = 0;
1004   RawFlags |= Flags.ReadNone;
1005   RawFlags |= (Flags.ReadOnly << 1);
1006   RawFlags |= (Flags.NoRecurse << 2);
1007   RawFlags |= (Flags.ReturnDoesNotAlias << 3);
1008   RawFlags |= (Flags.NoInline << 4);
1009   RawFlags |= (Flags.AlwaysInline << 5);
1010   return RawFlags;
1011 }
1012 
1013 // Decode the flags for GlobalValue in the summary
1014 static uint64_t getEncodedGVSummaryFlags(GlobalValueSummary::GVFlags Flags) {
1015   uint64_t RawFlags = 0;
1016 
1017   RawFlags |= Flags.NotEligibleToImport; // bool
1018   RawFlags |= (Flags.Live << 1);
1019   RawFlags |= (Flags.DSOLocal << 2);
1020   RawFlags |= (Flags.CanAutoHide << 3);
1021 
1022   // Linkage don't need to be remapped at that time for the summary. Any future
1023   // change to the getEncodedLinkage() function will need to be taken into
1024   // account here as well.
1025   RawFlags = (RawFlags << 4) | Flags.Linkage; // 4 bits
1026 
1027   return RawFlags;
1028 }
1029 
1030 static uint64_t getEncodedGVarFlags(GlobalVarSummary::GVarFlags Flags) {
1031   uint64_t RawFlags = Flags.MaybeReadOnly | (Flags.MaybeWriteOnly << 1) |
1032                       (Flags.Constant << 2) | Flags.VCallVisibility << 3;
1033   return RawFlags;
1034 }
1035 
1036 static unsigned getEncodedVisibility(const GlobalValue &GV) {
1037   switch (GV.getVisibility()) {
1038   case GlobalValue::DefaultVisibility:   return 0;
1039   case GlobalValue::HiddenVisibility:    return 1;
1040   case GlobalValue::ProtectedVisibility: return 2;
1041   }
1042   llvm_unreachable("Invalid visibility");
1043 }
1044 
1045 static unsigned getEncodedDLLStorageClass(const GlobalValue &GV) {
1046   switch (GV.getDLLStorageClass()) {
1047   case GlobalValue::DefaultStorageClass:   return 0;
1048   case GlobalValue::DLLImportStorageClass: return 1;
1049   case GlobalValue::DLLExportStorageClass: return 2;
1050   }
1051   llvm_unreachable("Invalid DLL storage class");
1052 }
1053 
1054 static unsigned getEncodedThreadLocalMode(const GlobalValue &GV) {
1055   switch (GV.getThreadLocalMode()) {
1056     case GlobalVariable::NotThreadLocal:         return 0;
1057     case GlobalVariable::GeneralDynamicTLSModel: return 1;
1058     case GlobalVariable::LocalDynamicTLSModel:   return 2;
1059     case GlobalVariable::InitialExecTLSModel:    return 3;
1060     case GlobalVariable::LocalExecTLSModel:      return 4;
1061   }
1062   llvm_unreachable("Invalid TLS model");
1063 }
1064 
1065 static unsigned getEncodedComdatSelectionKind(const Comdat &C) {
1066   switch (C.getSelectionKind()) {
1067   case Comdat::Any:
1068     return bitc::COMDAT_SELECTION_KIND_ANY;
1069   case Comdat::ExactMatch:
1070     return bitc::COMDAT_SELECTION_KIND_EXACT_MATCH;
1071   case Comdat::Largest:
1072     return bitc::COMDAT_SELECTION_KIND_LARGEST;
1073   case Comdat::NoDuplicates:
1074     return bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES;
1075   case Comdat::SameSize:
1076     return bitc::COMDAT_SELECTION_KIND_SAME_SIZE;
1077   }
1078   llvm_unreachable("Invalid selection kind");
1079 }
1080 
1081 static unsigned getEncodedUnnamedAddr(const GlobalValue &GV) {
1082   switch (GV.getUnnamedAddr()) {
1083   case GlobalValue::UnnamedAddr::None:   return 0;
1084   case GlobalValue::UnnamedAddr::Local:  return 2;
1085   case GlobalValue::UnnamedAddr::Global: return 1;
1086   }
1087   llvm_unreachable("Invalid unnamed_addr");
1088 }
1089 
1090 size_t ModuleBitcodeWriter::addToStrtab(StringRef Str) {
1091   if (GenerateHash)
1092     Hasher.update(Str);
1093   return StrtabBuilder.add(Str);
1094 }
1095 
1096 void ModuleBitcodeWriter::writeComdats() {
1097   SmallVector<unsigned, 64> Vals;
1098   for (const Comdat *C : VE.getComdats()) {
1099     // COMDAT: [strtab offset, strtab size, selection_kind]
1100     Vals.push_back(addToStrtab(C->getName()));
1101     Vals.push_back(C->getName().size());
1102     Vals.push_back(getEncodedComdatSelectionKind(*C));
1103     Stream.EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
1104     Vals.clear();
1105   }
1106 }
1107 
1108 /// Write a record that will eventually hold the word offset of the
1109 /// module-level VST. For now the offset is 0, which will be backpatched
1110 /// after the real VST is written. Saves the bit offset to backpatch.
1111 void ModuleBitcodeWriter::writeValueSymbolTableForwardDecl() {
1112   // Write a placeholder value in for the offset of the real VST,
1113   // which is written after the function blocks so that it can include
1114   // the offset of each function. The placeholder offset will be
1115   // updated when the real VST is written.
1116   auto Abbv = std::make_shared<BitCodeAbbrev>();
1117   Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_VSTOFFSET));
1118   // Blocks are 32-bit aligned, so we can use a 32-bit word offset to
1119   // hold the real VST offset. Must use fixed instead of VBR as we don't
1120   // know how many VBR chunks to reserve ahead of time.
1121   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
1122   unsigned VSTOffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1123 
1124   // Emit the placeholder
1125   uint64_t Vals[] = {bitc::MODULE_CODE_VSTOFFSET, 0};
1126   Stream.EmitRecordWithAbbrev(VSTOffsetAbbrev, Vals);
1127 
1128   // Compute and save the bit offset to the placeholder, which will be
1129   // patched when the real VST is written. We can simply subtract the 32-bit
1130   // fixed size from the current bit number to get the location to backpatch.
1131   VSTOffsetPlaceholder = Stream.GetCurrentBitNo() - 32;
1132 }
1133 
1134 enum StringEncoding { SE_Char6, SE_Fixed7, SE_Fixed8 };
1135 
1136 /// Determine the encoding to use for the given string name and length.
1137 static StringEncoding getStringEncoding(StringRef Str) {
1138   bool isChar6 = true;
1139   for (char C : Str) {
1140     if (isChar6)
1141       isChar6 = BitCodeAbbrevOp::isChar6(C);
1142     if ((unsigned char)C & 128)
1143       // don't bother scanning the rest.
1144       return SE_Fixed8;
1145   }
1146   if (isChar6)
1147     return SE_Char6;
1148   return SE_Fixed7;
1149 }
1150 
1151 /// Emit top-level description of module, including target triple, inline asm,
1152 /// descriptors for global variables, and function prototype info.
1153 /// Returns the bit offset to backpatch with the location of the real VST.
1154 void ModuleBitcodeWriter::writeModuleInfo() {
1155   // Emit various pieces of data attached to a module.
1156   if (!M.getTargetTriple().empty())
1157     writeStringRecord(Stream, bitc::MODULE_CODE_TRIPLE, M.getTargetTriple(),
1158                       0 /*TODO*/);
1159   const std::string &DL = M.getDataLayoutStr();
1160   if (!DL.empty())
1161     writeStringRecord(Stream, bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/);
1162   if (!M.getModuleInlineAsm().empty())
1163     writeStringRecord(Stream, bitc::MODULE_CODE_ASM, M.getModuleInlineAsm(),
1164                       0 /*TODO*/);
1165 
1166   // Emit information about sections and GC, computing how many there are. Also
1167   // compute the maximum alignment value.
1168   std::map<std::string, unsigned> SectionMap;
1169   std::map<std::string, unsigned> GCMap;
1170   unsigned MaxAlignment = 0;
1171   unsigned MaxGlobalType = 0;
1172   for (const GlobalValue &GV : M.globals()) {
1173     MaxAlignment = std::max(MaxAlignment, GV.getAlignment());
1174     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getValueType()));
1175     if (GV.hasSection()) {
1176       // Give section names unique ID's.
1177       unsigned &Entry = SectionMap[std::string(GV.getSection())];
1178       if (!Entry) {
1179         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
1180                           0 /*TODO*/);
1181         Entry = SectionMap.size();
1182       }
1183     }
1184   }
1185   for (const Function &F : M) {
1186     MaxAlignment = std::max(MaxAlignment, F.getAlignment());
1187     if (F.hasSection()) {
1188       // Give section names unique ID's.
1189       unsigned &Entry = SectionMap[std::string(F.getSection())];
1190       if (!Entry) {
1191         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
1192                           0 /*TODO*/);
1193         Entry = SectionMap.size();
1194       }
1195     }
1196     if (F.hasGC()) {
1197       // Same for GC names.
1198       unsigned &Entry = GCMap[F.getGC()];
1199       if (!Entry) {
1200         writeStringRecord(Stream, bitc::MODULE_CODE_GCNAME, F.getGC(),
1201                           0 /*TODO*/);
1202         Entry = GCMap.size();
1203       }
1204     }
1205   }
1206 
1207   // Emit abbrev for globals, now that we know # sections and max alignment.
1208   unsigned SimpleGVarAbbrev = 0;
1209   if (!M.global_empty()) {
1210     // Add an abbrev for common globals with no visibility or thread localness.
1211     auto Abbv = std::make_shared<BitCodeAbbrev>();
1212     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
1213     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1214     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1215     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1216                               Log2_32_Ceil(MaxGlobalType+1)));
1217     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddrSpace << 2
1218                                                            //| explicitType << 1
1219                                                            //| constant
1220     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Initializer.
1221     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // Linkage.
1222     if (MaxAlignment == 0)                                 // Alignment.
1223       Abbv->Add(BitCodeAbbrevOp(0));
1224     else {
1225       unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
1226       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1227                                Log2_32_Ceil(MaxEncAlignment+1)));
1228     }
1229     if (SectionMap.empty())                                    // Section.
1230       Abbv->Add(BitCodeAbbrevOp(0));
1231     else
1232       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1233                                Log2_32_Ceil(SectionMap.size()+1)));
1234     // Don't bother emitting vis + thread local.
1235     SimpleGVarAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1236   }
1237 
1238   SmallVector<unsigned, 64> Vals;
1239   // Emit the module's source file name.
1240   {
1241     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
1242     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
1243     if (Bits == SE_Char6)
1244       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
1245     else if (Bits == SE_Fixed7)
1246       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
1247 
1248     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
1249     auto Abbv = std::make_shared<BitCodeAbbrev>();
1250     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
1251     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1252     Abbv->Add(AbbrevOpToUse);
1253     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1254 
1255     for (const auto P : M.getSourceFileName())
1256       Vals.push_back((unsigned char)P);
1257 
1258     // Emit the finished record.
1259     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
1260     Vals.clear();
1261   }
1262 
1263   // Emit the global variable information.
1264   for (const GlobalVariable &GV : M.globals()) {
1265     unsigned AbbrevToUse = 0;
1266 
1267     // GLOBALVAR: [strtab offset, strtab size, type, isconst, initid,
1268     //             linkage, alignment, section, visibility, threadlocal,
1269     //             unnamed_addr, externally_initialized, dllstorageclass,
1270     //             comdat, attributes, DSO_Local]
1271     Vals.push_back(addToStrtab(GV.getName()));
1272     Vals.push_back(GV.getName().size());
1273     Vals.push_back(VE.getTypeID(GV.getValueType()));
1274     Vals.push_back(GV.getType()->getAddressSpace() << 2 | 2 | GV.isConstant());
1275     Vals.push_back(GV.isDeclaration() ? 0 :
1276                    (VE.getValueID(GV.getInitializer()) + 1));
1277     Vals.push_back(getEncodedLinkage(GV));
1278     Vals.push_back(Log2_32(GV.getAlignment())+1);
1279     Vals.push_back(GV.hasSection() ? SectionMap[std::string(GV.getSection())]
1280                                    : 0);
1281     if (GV.isThreadLocal() ||
1282         GV.getVisibility() != GlobalValue::DefaultVisibility ||
1283         GV.getUnnamedAddr() != GlobalValue::UnnamedAddr::None ||
1284         GV.isExternallyInitialized() ||
1285         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
1286         GV.hasComdat() ||
1287         GV.hasAttributes() ||
1288         GV.isDSOLocal() ||
1289         GV.hasPartition()) {
1290       Vals.push_back(getEncodedVisibility(GV));
1291       Vals.push_back(getEncodedThreadLocalMode(GV));
1292       Vals.push_back(getEncodedUnnamedAddr(GV));
1293       Vals.push_back(GV.isExternallyInitialized());
1294       Vals.push_back(getEncodedDLLStorageClass(GV));
1295       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
1296 
1297       auto AL = GV.getAttributesAsList(AttributeList::FunctionIndex);
1298       Vals.push_back(VE.getAttributeListID(AL));
1299 
1300       Vals.push_back(GV.isDSOLocal());
1301       Vals.push_back(addToStrtab(GV.getPartition()));
1302       Vals.push_back(GV.getPartition().size());
1303     } else {
1304       AbbrevToUse = SimpleGVarAbbrev;
1305     }
1306 
1307     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
1308     Vals.clear();
1309   }
1310 
1311   // Emit the function proto information.
1312   for (const Function &F : M) {
1313     // FUNCTION:  [strtab offset, strtab size, type, callingconv, isproto,
1314     //             linkage, paramattrs, alignment, section, visibility, gc,
1315     //             unnamed_addr, prologuedata, dllstorageclass, comdat,
1316     //             prefixdata, personalityfn, DSO_Local, addrspace]
1317     Vals.push_back(addToStrtab(F.getName()));
1318     Vals.push_back(F.getName().size());
1319     Vals.push_back(VE.getTypeID(F.getFunctionType()));
1320     Vals.push_back(F.getCallingConv());
1321     Vals.push_back(F.isDeclaration());
1322     Vals.push_back(getEncodedLinkage(F));
1323     Vals.push_back(VE.getAttributeListID(F.getAttributes()));
1324     Vals.push_back(Log2_32(F.getAlignment())+1);
1325     Vals.push_back(F.hasSection() ? SectionMap[std::string(F.getSection())]
1326                                   : 0);
1327     Vals.push_back(getEncodedVisibility(F));
1328     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
1329     Vals.push_back(getEncodedUnnamedAddr(F));
1330     Vals.push_back(F.hasPrologueData() ? (VE.getValueID(F.getPrologueData()) + 1)
1331                                        : 0);
1332     Vals.push_back(getEncodedDLLStorageClass(F));
1333     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
1334     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
1335                                      : 0);
1336     Vals.push_back(
1337         F.hasPersonalityFn() ? (VE.getValueID(F.getPersonalityFn()) + 1) : 0);
1338 
1339     Vals.push_back(F.isDSOLocal());
1340     Vals.push_back(F.getAddressSpace());
1341     Vals.push_back(addToStrtab(F.getPartition()));
1342     Vals.push_back(F.getPartition().size());
1343 
1344     unsigned AbbrevToUse = 0;
1345     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
1346     Vals.clear();
1347   }
1348 
1349   // Emit the alias information.
1350   for (const GlobalAlias &A : M.aliases()) {
1351     // ALIAS: [strtab offset, strtab size, alias type, aliasee val#, linkage,
1352     //         visibility, dllstorageclass, threadlocal, unnamed_addr,
1353     //         DSO_Local]
1354     Vals.push_back(addToStrtab(A.getName()));
1355     Vals.push_back(A.getName().size());
1356     Vals.push_back(VE.getTypeID(A.getValueType()));
1357     Vals.push_back(A.getType()->getAddressSpace());
1358     Vals.push_back(VE.getValueID(A.getAliasee()));
1359     Vals.push_back(getEncodedLinkage(A));
1360     Vals.push_back(getEncodedVisibility(A));
1361     Vals.push_back(getEncodedDLLStorageClass(A));
1362     Vals.push_back(getEncodedThreadLocalMode(A));
1363     Vals.push_back(getEncodedUnnamedAddr(A));
1364     Vals.push_back(A.isDSOLocal());
1365     Vals.push_back(addToStrtab(A.getPartition()));
1366     Vals.push_back(A.getPartition().size());
1367 
1368     unsigned AbbrevToUse = 0;
1369     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
1370     Vals.clear();
1371   }
1372 
1373   // Emit the ifunc information.
1374   for (const GlobalIFunc &I : M.ifuncs()) {
1375     // IFUNC: [strtab offset, strtab size, ifunc type, address space, resolver
1376     //         val#, linkage, visibility, DSO_Local]
1377     Vals.push_back(addToStrtab(I.getName()));
1378     Vals.push_back(I.getName().size());
1379     Vals.push_back(VE.getTypeID(I.getValueType()));
1380     Vals.push_back(I.getType()->getAddressSpace());
1381     Vals.push_back(VE.getValueID(I.getResolver()));
1382     Vals.push_back(getEncodedLinkage(I));
1383     Vals.push_back(getEncodedVisibility(I));
1384     Vals.push_back(I.isDSOLocal());
1385     Vals.push_back(addToStrtab(I.getPartition()));
1386     Vals.push_back(I.getPartition().size());
1387     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
1388     Vals.clear();
1389   }
1390 
1391   writeValueSymbolTableForwardDecl();
1392 }
1393 
1394 static uint64_t getOptimizationFlags(const Value *V) {
1395   uint64_t Flags = 0;
1396 
1397   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
1398     if (OBO->hasNoSignedWrap())
1399       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
1400     if (OBO->hasNoUnsignedWrap())
1401       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
1402   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
1403     if (PEO->isExact())
1404       Flags |= 1 << bitc::PEO_EXACT;
1405   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
1406     if (FPMO->hasAllowReassoc())
1407       Flags |= bitc::AllowReassoc;
1408     if (FPMO->hasNoNaNs())
1409       Flags |= bitc::NoNaNs;
1410     if (FPMO->hasNoInfs())
1411       Flags |= bitc::NoInfs;
1412     if (FPMO->hasNoSignedZeros())
1413       Flags |= bitc::NoSignedZeros;
1414     if (FPMO->hasAllowReciprocal())
1415       Flags |= bitc::AllowReciprocal;
1416     if (FPMO->hasAllowContract())
1417       Flags |= bitc::AllowContract;
1418     if (FPMO->hasApproxFunc())
1419       Flags |= bitc::ApproxFunc;
1420   }
1421 
1422   return Flags;
1423 }
1424 
1425 void ModuleBitcodeWriter::writeValueAsMetadata(
1426     const ValueAsMetadata *MD, SmallVectorImpl<uint64_t> &Record) {
1427   // Mimic an MDNode with a value as one operand.
1428   Value *V = MD->getValue();
1429   Record.push_back(VE.getTypeID(V->getType()));
1430   Record.push_back(VE.getValueID(V));
1431   Stream.EmitRecord(bitc::METADATA_VALUE, Record, 0);
1432   Record.clear();
1433 }
1434 
1435 void ModuleBitcodeWriter::writeMDTuple(const MDTuple *N,
1436                                        SmallVectorImpl<uint64_t> &Record,
1437                                        unsigned Abbrev) {
1438   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
1439     Metadata *MD = N->getOperand(i);
1440     assert(!(MD && isa<LocalAsMetadata>(MD)) &&
1441            "Unexpected function-local metadata");
1442     Record.push_back(VE.getMetadataOrNullID(MD));
1443   }
1444   Stream.EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
1445                                     : bitc::METADATA_NODE,
1446                     Record, Abbrev);
1447   Record.clear();
1448 }
1449 
1450 unsigned ModuleBitcodeWriter::createDILocationAbbrev() {
1451   // Assume the column is usually under 128, and always output the inlined-at
1452   // location (it's never more expensive than building an array size 1).
1453   auto Abbv = std::make_shared<BitCodeAbbrev>();
1454   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
1455   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1456   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1457   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1458   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1459   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1460   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1461   return Stream.EmitAbbrev(std::move(Abbv));
1462 }
1463 
1464 void ModuleBitcodeWriter::writeDILocation(const DILocation *N,
1465                                           SmallVectorImpl<uint64_t> &Record,
1466                                           unsigned &Abbrev) {
1467   if (!Abbrev)
1468     Abbrev = createDILocationAbbrev();
1469 
1470   Record.push_back(N->isDistinct());
1471   Record.push_back(N->getLine());
1472   Record.push_back(N->getColumn());
1473   Record.push_back(VE.getMetadataID(N->getScope()));
1474   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
1475   Record.push_back(N->isImplicitCode());
1476 
1477   Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
1478   Record.clear();
1479 }
1480 
1481 unsigned ModuleBitcodeWriter::createGenericDINodeAbbrev() {
1482   // Assume the column is usually under 128, and always output the inlined-at
1483   // location (it's never more expensive than building an array size 1).
1484   auto Abbv = std::make_shared<BitCodeAbbrev>();
1485   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
1486   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1487   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1488   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1489   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1490   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1491   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1492   return Stream.EmitAbbrev(std::move(Abbv));
1493 }
1494 
1495 void ModuleBitcodeWriter::writeGenericDINode(const GenericDINode *N,
1496                                              SmallVectorImpl<uint64_t> &Record,
1497                                              unsigned &Abbrev) {
1498   if (!Abbrev)
1499     Abbrev = createGenericDINodeAbbrev();
1500 
1501   Record.push_back(N->isDistinct());
1502   Record.push_back(N->getTag());
1503   Record.push_back(0); // Per-tag version field; unused for now.
1504 
1505   for (auto &I : N->operands())
1506     Record.push_back(VE.getMetadataOrNullID(I));
1507 
1508   Stream.EmitRecord(bitc::METADATA_GENERIC_DEBUG, Record, Abbrev);
1509   Record.clear();
1510 }
1511 
1512 static uint64_t rotateSign(int64_t I) {
1513   uint64_t U = I;
1514   return I < 0 ? ~(U << 1) : U << 1;
1515 }
1516 
1517 void ModuleBitcodeWriter::writeDISubrange(const DISubrange *N,
1518                                           SmallVectorImpl<uint64_t> &Record,
1519                                           unsigned Abbrev) {
1520   const uint64_t Version = 1 << 1;
1521   Record.push_back((uint64_t)N->isDistinct() | Version);
1522   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1523   Record.push_back(rotateSign(N->getLowerBound()));
1524 
1525   Stream.EmitRecord(bitc::METADATA_SUBRANGE, Record, Abbrev);
1526   Record.clear();
1527 }
1528 
1529 void ModuleBitcodeWriter::writeDIEnumerator(const DIEnumerator *N,
1530                                             SmallVectorImpl<uint64_t> &Record,
1531                                             unsigned Abbrev) {
1532   Record.push_back((N->isUnsigned() << 1) | N->isDistinct());
1533   Record.push_back(rotateSign(N->getValue()));
1534   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1535 
1536   Stream.EmitRecord(bitc::METADATA_ENUMERATOR, Record, Abbrev);
1537   Record.clear();
1538 }
1539 
1540 void ModuleBitcodeWriter::writeDIBasicType(const DIBasicType *N,
1541                                            SmallVectorImpl<uint64_t> &Record,
1542                                            unsigned Abbrev) {
1543   Record.push_back(N->isDistinct());
1544   Record.push_back(N->getTag());
1545   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1546   Record.push_back(N->getSizeInBits());
1547   Record.push_back(N->getAlignInBits());
1548   Record.push_back(N->getEncoding());
1549   Record.push_back(N->getFlags());
1550 
1551   Stream.EmitRecord(bitc::METADATA_BASIC_TYPE, Record, Abbrev);
1552   Record.clear();
1553 }
1554 
1555 void ModuleBitcodeWriter::writeDIDerivedType(const DIDerivedType *N,
1556                                              SmallVectorImpl<uint64_t> &Record,
1557                                              unsigned Abbrev) {
1558   Record.push_back(N->isDistinct());
1559   Record.push_back(N->getTag());
1560   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1561   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1562   Record.push_back(N->getLine());
1563   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1564   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1565   Record.push_back(N->getSizeInBits());
1566   Record.push_back(N->getAlignInBits());
1567   Record.push_back(N->getOffsetInBits());
1568   Record.push_back(N->getFlags());
1569   Record.push_back(VE.getMetadataOrNullID(N->getExtraData()));
1570 
1571   // DWARF address space is encoded as N->getDWARFAddressSpace() + 1. 0 means
1572   // that there is no DWARF address space associated with DIDerivedType.
1573   if (const auto &DWARFAddressSpace = N->getDWARFAddressSpace())
1574     Record.push_back(*DWARFAddressSpace + 1);
1575   else
1576     Record.push_back(0);
1577 
1578   Stream.EmitRecord(bitc::METADATA_DERIVED_TYPE, Record, Abbrev);
1579   Record.clear();
1580 }
1581 
1582 void ModuleBitcodeWriter::writeDICompositeType(
1583     const DICompositeType *N, SmallVectorImpl<uint64_t> &Record,
1584     unsigned Abbrev) {
1585   const unsigned IsNotUsedInOldTypeRef = 0x2;
1586   Record.push_back(IsNotUsedInOldTypeRef | (unsigned)N->isDistinct());
1587   Record.push_back(N->getTag());
1588   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1589   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1590   Record.push_back(N->getLine());
1591   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1592   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1593   Record.push_back(N->getSizeInBits());
1594   Record.push_back(N->getAlignInBits());
1595   Record.push_back(N->getOffsetInBits());
1596   Record.push_back(N->getFlags());
1597   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1598   Record.push_back(N->getRuntimeLang());
1599   Record.push_back(VE.getMetadataOrNullID(N->getVTableHolder()));
1600   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1601   Record.push_back(VE.getMetadataOrNullID(N->getRawIdentifier()));
1602   Record.push_back(VE.getMetadataOrNullID(N->getDiscriminator()));
1603 
1604   Stream.EmitRecord(bitc::METADATA_COMPOSITE_TYPE, Record, Abbrev);
1605   Record.clear();
1606 }
1607 
1608 void ModuleBitcodeWriter::writeDISubroutineType(
1609     const DISubroutineType *N, SmallVectorImpl<uint64_t> &Record,
1610     unsigned Abbrev) {
1611   const unsigned HasNoOldTypeRefs = 0x2;
1612   Record.push_back(HasNoOldTypeRefs | (unsigned)N->isDistinct());
1613   Record.push_back(N->getFlags());
1614   Record.push_back(VE.getMetadataOrNullID(N->getTypeArray().get()));
1615   Record.push_back(N->getCC());
1616 
1617   Stream.EmitRecord(bitc::METADATA_SUBROUTINE_TYPE, Record, Abbrev);
1618   Record.clear();
1619 }
1620 
1621 void ModuleBitcodeWriter::writeDIFile(const DIFile *N,
1622                                       SmallVectorImpl<uint64_t> &Record,
1623                                       unsigned Abbrev) {
1624   Record.push_back(N->isDistinct());
1625   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
1626   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
1627   if (N->getRawChecksum()) {
1628     Record.push_back(N->getRawChecksum()->Kind);
1629     Record.push_back(VE.getMetadataOrNullID(N->getRawChecksum()->Value));
1630   } else {
1631     // Maintain backwards compatibility with the old internal representation of
1632     // CSK_None in ChecksumKind by writing nulls here when Checksum is None.
1633     Record.push_back(0);
1634     Record.push_back(VE.getMetadataOrNullID(nullptr));
1635   }
1636   auto Source = N->getRawSource();
1637   if (Source)
1638     Record.push_back(VE.getMetadataOrNullID(*Source));
1639 
1640   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
1641   Record.clear();
1642 }
1643 
1644 void ModuleBitcodeWriter::writeDICompileUnit(const DICompileUnit *N,
1645                                              SmallVectorImpl<uint64_t> &Record,
1646                                              unsigned Abbrev) {
1647   assert(N->isDistinct() && "Expected distinct compile units");
1648   Record.push_back(/* IsDistinct */ true);
1649   Record.push_back(N->getSourceLanguage());
1650   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1651   Record.push_back(VE.getMetadataOrNullID(N->getRawProducer()));
1652   Record.push_back(N->isOptimized());
1653   Record.push_back(VE.getMetadataOrNullID(N->getRawFlags()));
1654   Record.push_back(N->getRuntimeVersion());
1655   Record.push_back(VE.getMetadataOrNullID(N->getRawSplitDebugFilename()));
1656   Record.push_back(N->getEmissionKind());
1657   Record.push_back(VE.getMetadataOrNullID(N->getEnumTypes().get()));
1658   Record.push_back(VE.getMetadataOrNullID(N->getRetainedTypes().get()));
1659   Record.push_back(/* subprograms */ 0);
1660   Record.push_back(VE.getMetadataOrNullID(N->getGlobalVariables().get()));
1661   Record.push_back(VE.getMetadataOrNullID(N->getImportedEntities().get()));
1662   Record.push_back(N->getDWOId());
1663   Record.push_back(VE.getMetadataOrNullID(N->getMacros().get()));
1664   Record.push_back(N->getSplitDebugInlining());
1665   Record.push_back(N->getDebugInfoForProfiling());
1666   Record.push_back((unsigned)N->getNameTableKind());
1667   Record.push_back(N->getRangesBaseAddress());
1668   Record.push_back(VE.getMetadataOrNullID(N->getRawSysRoot()));
1669 
1670   Stream.EmitRecord(bitc::METADATA_COMPILE_UNIT, Record, Abbrev);
1671   Record.clear();
1672 }
1673 
1674 void ModuleBitcodeWriter::writeDISubprogram(const DISubprogram *N,
1675                                             SmallVectorImpl<uint64_t> &Record,
1676                                             unsigned Abbrev) {
1677   const uint64_t HasUnitFlag = 1 << 1;
1678   const uint64_t HasSPFlagsFlag = 1 << 2;
1679   Record.push_back(uint64_t(N->isDistinct()) | HasUnitFlag | HasSPFlagsFlag);
1680   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1681   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1682   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1683   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1684   Record.push_back(N->getLine());
1685   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1686   Record.push_back(N->getScopeLine());
1687   Record.push_back(VE.getMetadataOrNullID(N->getContainingType()));
1688   Record.push_back(N->getSPFlags());
1689   Record.push_back(N->getVirtualIndex());
1690   Record.push_back(N->getFlags());
1691   Record.push_back(VE.getMetadataOrNullID(N->getRawUnit()));
1692   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1693   Record.push_back(VE.getMetadataOrNullID(N->getDeclaration()));
1694   Record.push_back(VE.getMetadataOrNullID(N->getRetainedNodes().get()));
1695   Record.push_back(N->getThisAdjustment());
1696   Record.push_back(VE.getMetadataOrNullID(N->getThrownTypes().get()));
1697 
1698   Stream.EmitRecord(bitc::METADATA_SUBPROGRAM, Record, Abbrev);
1699   Record.clear();
1700 }
1701 
1702 void ModuleBitcodeWriter::writeDILexicalBlock(const DILexicalBlock *N,
1703                                               SmallVectorImpl<uint64_t> &Record,
1704                                               unsigned Abbrev) {
1705   Record.push_back(N->isDistinct());
1706   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1707   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1708   Record.push_back(N->getLine());
1709   Record.push_back(N->getColumn());
1710 
1711   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK, Record, Abbrev);
1712   Record.clear();
1713 }
1714 
1715 void ModuleBitcodeWriter::writeDILexicalBlockFile(
1716     const DILexicalBlockFile *N, SmallVectorImpl<uint64_t> &Record,
1717     unsigned Abbrev) {
1718   Record.push_back(N->isDistinct());
1719   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1720   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1721   Record.push_back(N->getDiscriminator());
1722 
1723   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK_FILE, Record, Abbrev);
1724   Record.clear();
1725 }
1726 
1727 void ModuleBitcodeWriter::writeDICommonBlock(const DICommonBlock *N,
1728                                              SmallVectorImpl<uint64_t> &Record,
1729                                              unsigned Abbrev) {
1730   Record.push_back(N->isDistinct());
1731   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1732   Record.push_back(VE.getMetadataOrNullID(N->getDecl()));
1733   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1734   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1735   Record.push_back(N->getLineNo());
1736 
1737   Stream.EmitRecord(bitc::METADATA_COMMON_BLOCK, Record, Abbrev);
1738   Record.clear();
1739 }
1740 
1741 void ModuleBitcodeWriter::writeDINamespace(const DINamespace *N,
1742                                            SmallVectorImpl<uint64_t> &Record,
1743                                            unsigned Abbrev) {
1744   Record.push_back(N->isDistinct() | N->getExportSymbols() << 1);
1745   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1746   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1747 
1748   Stream.EmitRecord(bitc::METADATA_NAMESPACE, Record, Abbrev);
1749   Record.clear();
1750 }
1751 
1752 void ModuleBitcodeWriter::writeDIMacro(const DIMacro *N,
1753                                        SmallVectorImpl<uint64_t> &Record,
1754                                        unsigned Abbrev) {
1755   Record.push_back(N->isDistinct());
1756   Record.push_back(N->getMacinfoType());
1757   Record.push_back(N->getLine());
1758   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1759   Record.push_back(VE.getMetadataOrNullID(N->getRawValue()));
1760 
1761   Stream.EmitRecord(bitc::METADATA_MACRO, Record, Abbrev);
1762   Record.clear();
1763 }
1764 
1765 void ModuleBitcodeWriter::writeDIMacroFile(const DIMacroFile *N,
1766                                            SmallVectorImpl<uint64_t> &Record,
1767                                            unsigned Abbrev) {
1768   Record.push_back(N->isDistinct());
1769   Record.push_back(N->getMacinfoType());
1770   Record.push_back(N->getLine());
1771   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1772   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1773 
1774   Stream.EmitRecord(bitc::METADATA_MACRO_FILE, Record, Abbrev);
1775   Record.clear();
1776 }
1777 
1778 void ModuleBitcodeWriter::writeDIModule(const DIModule *N,
1779                                         SmallVectorImpl<uint64_t> &Record,
1780                                         unsigned Abbrev) {
1781   Record.push_back(N->isDistinct());
1782   for (auto &I : N->operands())
1783     Record.push_back(VE.getMetadataOrNullID(I));
1784 
1785   Stream.EmitRecord(bitc::METADATA_MODULE, Record, Abbrev);
1786   Record.clear();
1787 }
1788 
1789 void ModuleBitcodeWriter::writeDITemplateTypeParameter(
1790     const DITemplateTypeParameter *N, SmallVectorImpl<uint64_t> &Record,
1791     unsigned Abbrev) {
1792   Record.push_back(N->isDistinct());
1793   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1794   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1795 
1796   Stream.EmitRecord(bitc::METADATA_TEMPLATE_TYPE, Record, Abbrev);
1797   Record.clear();
1798 }
1799 
1800 void ModuleBitcodeWriter::writeDITemplateValueParameter(
1801     const DITemplateValueParameter *N, SmallVectorImpl<uint64_t> &Record,
1802     unsigned Abbrev) {
1803   Record.push_back(N->isDistinct());
1804   Record.push_back(N->getTag());
1805   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1806   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1807   Record.push_back(VE.getMetadataOrNullID(N->getValue()));
1808 
1809   Stream.EmitRecord(bitc::METADATA_TEMPLATE_VALUE, Record, Abbrev);
1810   Record.clear();
1811 }
1812 
1813 void ModuleBitcodeWriter::writeDIGlobalVariable(
1814     const DIGlobalVariable *N, SmallVectorImpl<uint64_t> &Record,
1815     unsigned Abbrev) {
1816   const uint64_t Version = 2 << 1;
1817   Record.push_back((uint64_t)N->isDistinct() | Version);
1818   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1819   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1820   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1821   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1822   Record.push_back(N->getLine());
1823   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1824   Record.push_back(N->isLocalToUnit());
1825   Record.push_back(N->isDefinition());
1826   Record.push_back(VE.getMetadataOrNullID(N->getStaticDataMemberDeclaration()));
1827   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams()));
1828   Record.push_back(N->getAlignInBits());
1829 
1830   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR, Record, Abbrev);
1831   Record.clear();
1832 }
1833 
1834 void ModuleBitcodeWriter::writeDILocalVariable(
1835     const DILocalVariable *N, SmallVectorImpl<uint64_t> &Record,
1836     unsigned Abbrev) {
1837   // In order to support all possible bitcode formats in BitcodeReader we need
1838   // to distinguish the following cases:
1839   // 1) Record has no artificial tag (Record[1]),
1840   //   has no obsolete inlinedAt field (Record[9]).
1841   //   In this case Record size will be 8, HasAlignment flag is false.
1842   // 2) Record has artificial tag (Record[1]),
1843   //   has no obsolete inlignedAt field (Record[9]).
1844   //   In this case Record size will be 9, HasAlignment flag is false.
1845   // 3) Record has both artificial tag (Record[1]) and
1846   //   obsolete inlignedAt field (Record[9]).
1847   //   In this case Record size will be 10, HasAlignment flag is false.
1848   // 4) Record has neither artificial tag, nor inlignedAt field, but
1849   //   HasAlignment flag is true and Record[8] contains alignment value.
1850   const uint64_t HasAlignmentFlag = 1 << 1;
1851   Record.push_back((uint64_t)N->isDistinct() | HasAlignmentFlag);
1852   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1853   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1854   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1855   Record.push_back(N->getLine());
1856   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1857   Record.push_back(N->getArg());
1858   Record.push_back(N->getFlags());
1859   Record.push_back(N->getAlignInBits());
1860 
1861   Stream.EmitRecord(bitc::METADATA_LOCAL_VAR, Record, Abbrev);
1862   Record.clear();
1863 }
1864 
1865 void ModuleBitcodeWriter::writeDILabel(
1866     const DILabel *N, SmallVectorImpl<uint64_t> &Record,
1867     unsigned Abbrev) {
1868   Record.push_back((uint64_t)N->isDistinct());
1869   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1870   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1871   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1872   Record.push_back(N->getLine());
1873 
1874   Stream.EmitRecord(bitc::METADATA_LABEL, Record, Abbrev);
1875   Record.clear();
1876 }
1877 
1878 void ModuleBitcodeWriter::writeDIExpression(const DIExpression *N,
1879                                             SmallVectorImpl<uint64_t> &Record,
1880                                             unsigned Abbrev) {
1881   Record.reserve(N->getElements().size() + 1);
1882   const uint64_t Version = 3 << 1;
1883   Record.push_back((uint64_t)N->isDistinct() | Version);
1884   Record.append(N->elements_begin(), N->elements_end());
1885 
1886   Stream.EmitRecord(bitc::METADATA_EXPRESSION, Record, Abbrev);
1887   Record.clear();
1888 }
1889 
1890 void ModuleBitcodeWriter::writeDIGlobalVariableExpression(
1891     const DIGlobalVariableExpression *N, SmallVectorImpl<uint64_t> &Record,
1892     unsigned Abbrev) {
1893   Record.push_back(N->isDistinct());
1894   Record.push_back(VE.getMetadataOrNullID(N->getVariable()));
1895   Record.push_back(VE.getMetadataOrNullID(N->getExpression()));
1896 
1897   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR_EXPR, Record, Abbrev);
1898   Record.clear();
1899 }
1900 
1901 void ModuleBitcodeWriter::writeDIObjCProperty(const DIObjCProperty *N,
1902                                               SmallVectorImpl<uint64_t> &Record,
1903                                               unsigned Abbrev) {
1904   Record.push_back(N->isDistinct());
1905   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1906   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1907   Record.push_back(N->getLine());
1908   Record.push_back(VE.getMetadataOrNullID(N->getRawSetterName()));
1909   Record.push_back(VE.getMetadataOrNullID(N->getRawGetterName()));
1910   Record.push_back(N->getAttributes());
1911   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1912 
1913   Stream.EmitRecord(bitc::METADATA_OBJC_PROPERTY, Record, Abbrev);
1914   Record.clear();
1915 }
1916 
1917 void ModuleBitcodeWriter::writeDIImportedEntity(
1918     const DIImportedEntity *N, SmallVectorImpl<uint64_t> &Record,
1919     unsigned Abbrev) {
1920   Record.push_back(N->isDistinct());
1921   Record.push_back(N->getTag());
1922   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1923   Record.push_back(VE.getMetadataOrNullID(N->getEntity()));
1924   Record.push_back(N->getLine());
1925   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1926   Record.push_back(VE.getMetadataOrNullID(N->getRawFile()));
1927 
1928   Stream.EmitRecord(bitc::METADATA_IMPORTED_ENTITY, Record, Abbrev);
1929   Record.clear();
1930 }
1931 
1932 unsigned ModuleBitcodeWriter::createNamedMetadataAbbrev() {
1933   auto Abbv = std::make_shared<BitCodeAbbrev>();
1934   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
1935   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1936   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1937   return Stream.EmitAbbrev(std::move(Abbv));
1938 }
1939 
1940 void ModuleBitcodeWriter::writeNamedMetadata(
1941     SmallVectorImpl<uint64_t> &Record) {
1942   if (M.named_metadata_empty())
1943     return;
1944 
1945   unsigned Abbrev = createNamedMetadataAbbrev();
1946   for (const NamedMDNode &NMD : M.named_metadata()) {
1947     // Write name.
1948     StringRef Str = NMD.getName();
1949     Record.append(Str.bytes_begin(), Str.bytes_end());
1950     Stream.EmitRecord(bitc::METADATA_NAME, Record, Abbrev);
1951     Record.clear();
1952 
1953     // Write named metadata operands.
1954     for (const MDNode *N : NMD.operands())
1955       Record.push_back(VE.getMetadataID(N));
1956     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
1957     Record.clear();
1958   }
1959 }
1960 
1961 unsigned ModuleBitcodeWriter::createMetadataStringsAbbrev() {
1962   auto Abbv = std::make_shared<BitCodeAbbrev>();
1963   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRINGS));
1964   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // # of strings
1965   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // offset to chars
1966   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
1967   return Stream.EmitAbbrev(std::move(Abbv));
1968 }
1969 
1970 /// Write out a record for MDString.
1971 ///
1972 /// All the metadata strings in a metadata block are emitted in a single
1973 /// record.  The sizes and strings themselves are shoved into a blob.
1974 void ModuleBitcodeWriter::writeMetadataStrings(
1975     ArrayRef<const Metadata *> Strings, SmallVectorImpl<uint64_t> &Record) {
1976   if (Strings.empty())
1977     return;
1978 
1979   // Start the record with the number of strings.
1980   Record.push_back(bitc::METADATA_STRINGS);
1981   Record.push_back(Strings.size());
1982 
1983   // Emit the sizes of the strings in the blob.
1984   SmallString<256> Blob;
1985   {
1986     BitstreamWriter W(Blob);
1987     for (const Metadata *MD : Strings)
1988       W.EmitVBR(cast<MDString>(MD)->getLength(), 6);
1989     W.FlushToWord();
1990   }
1991 
1992   // Add the offset to the strings to the record.
1993   Record.push_back(Blob.size());
1994 
1995   // Add the strings to the blob.
1996   for (const Metadata *MD : Strings)
1997     Blob.append(cast<MDString>(MD)->getString());
1998 
1999   // Emit the final record.
2000   Stream.EmitRecordWithBlob(createMetadataStringsAbbrev(), Record, Blob);
2001   Record.clear();
2002 }
2003 
2004 // Generates an enum to use as an index in the Abbrev array of Metadata record.
2005 enum MetadataAbbrev : unsigned {
2006 #define HANDLE_MDNODE_LEAF(CLASS) CLASS##AbbrevID,
2007 #include "llvm/IR/Metadata.def"
2008   LastPlusOne
2009 };
2010 
2011 void ModuleBitcodeWriter::writeMetadataRecords(
2012     ArrayRef<const Metadata *> MDs, SmallVectorImpl<uint64_t> &Record,
2013     std::vector<unsigned> *MDAbbrevs, std::vector<uint64_t> *IndexPos) {
2014   if (MDs.empty())
2015     return;
2016 
2017   // Initialize MDNode abbreviations.
2018 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
2019 #include "llvm/IR/Metadata.def"
2020 
2021   for (const Metadata *MD : MDs) {
2022     if (IndexPos)
2023       IndexPos->push_back(Stream.GetCurrentBitNo());
2024     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
2025       assert(N->isResolved() && "Expected forward references to be resolved");
2026 
2027       switch (N->getMetadataID()) {
2028       default:
2029         llvm_unreachable("Invalid MDNode subclass");
2030 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
2031   case Metadata::CLASS##Kind:                                                  \
2032     if (MDAbbrevs)                                                             \
2033       write##CLASS(cast<CLASS>(N), Record,                                     \
2034                    (*MDAbbrevs)[MetadataAbbrev::CLASS##AbbrevID]);             \
2035     else                                                                       \
2036       write##CLASS(cast<CLASS>(N), Record, CLASS##Abbrev);                     \
2037     continue;
2038 #include "llvm/IR/Metadata.def"
2039       }
2040     }
2041     writeValueAsMetadata(cast<ValueAsMetadata>(MD), Record);
2042   }
2043 }
2044 
2045 void ModuleBitcodeWriter::writeModuleMetadata() {
2046   if (!VE.hasMDs() && M.named_metadata_empty())
2047     return;
2048 
2049   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 4);
2050   SmallVector<uint64_t, 64> Record;
2051 
2052   // Emit all abbrevs upfront, so that the reader can jump in the middle of the
2053   // block and load any metadata.
2054   std::vector<unsigned> MDAbbrevs;
2055 
2056   MDAbbrevs.resize(MetadataAbbrev::LastPlusOne);
2057   MDAbbrevs[MetadataAbbrev::DILocationAbbrevID] = createDILocationAbbrev();
2058   MDAbbrevs[MetadataAbbrev::GenericDINodeAbbrevID] =
2059       createGenericDINodeAbbrev();
2060 
2061   auto Abbv = std::make_shared<BitCodeAbbrev>();
2062   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX_OFFSET));
2063   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2064   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2065   unsigned OffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2066 
2067   Abbv = std::make_shared<BitCodeAbbrev>();
2068   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX));
2069   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2070   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2071   unsigned IndexAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2072 
2073   // Emit MDStrings together upfront.
2074   writeMetadataStrings(VE.getMDStrings(), Record);
2075 
2076   // We only emit an index for the metadata record if we have more than a given
2077   // (naive) threshold of metadatas, otherwise it is not worth it.
2078   if (VE.getNonMDStrings().size() > IndexThreshold) {
2079     // Write a placeholder value in for the offset of the metadata index,
2080     // which is written after the records, so that it can include
2081     // the offset of each entry. The placeholder offset will be
2082     // updated after all records are emitted.
2083     uint64_t Vals[] = {0, 0};
2084     Stream.EmitRecord(bitc::METADATA_INDEX_OFFSET, Vals, OffsetAbbrev);
2085   }
2086 
2087   // Compute and save the bit offset to the current position, which will be
2088   // patched when we emit the index later. We can simply subtract the 64-bit
2089   // fixed size from the current bit number to get the location to backpatch.
2090   uint64_t IndexOffsetRecordBitPos = Stream.GetCurrentBitNo();
2091 
2092   // This index will contain the bitpos for each individual record.
2093   std::vector<uint64_t> IndexPos;
2094   IndexPos.reserve(VE.getNonMDStrings().size());
2095 
2096   // Write all the records
2097   writeMetadataRecords(VE.getNonMDStrings(), Record, &MDAbbrevs, &IndexPos);
2098 
2099   if (VE.getNonMDStrings().size() > IndexThreshold) {
2100     // Now that we have emitted all the records we will emit the index. But
2101     // first
2102     // backpatch the forward reference so that the reader can skip the records
2103     // efficiently.
2104     Stream.BackpatchWord64(IndexOffsetRecordBitPos - 64,
2105                            Stream.GetCurrentBitNo() - IndexOffsetRecordBitPos);
2106 
2107     // Delta encode the index.
2108     uint64_t PreviousValue = IndexOffsetRecordBitPos;
2109     for (auto &Elt : IndexPos) {
2110       auto EltDelta = Elt - PreviousValue;
2111       PreviousValue = Elt;
2112       Elt = EltDelta;
2113     }
2114     // Emit the index record.
2115     Stream.EmitRecord(bitc::METADATA_INDEX, IndexPos, IndexAbbrev);
2116     IndexPos.clear();
2117   }
2118 
2119   // Write the named metadata now.
2120   writeNamedMetadata(Record);
2121 
2122   auto AddDeclAttachedMetadata = [&](const GlobalObject &GO) {
2123     SmallVector<uint64_t, 4> Record;
2124     Record.push_back(VE.getValueID(&GO));
2125     pushGlobalMetadataAttachment(Record, GO);
2126     Stream.EmitRecord(bitc::METADATA_GLOBAL_DECL_ATTACHMENT, Record);
2127   };
2128   for (const Function &F : M)
2129     if (F.isDeclaration() && F.hasMetadata())
2130       AddDeclAttachedMetadata(F);
2131   // FIXME: Only store metadata for declarations here, and move data for global
2132   // variable definitions to a separate block (PR28134).
2133   for (const GlobalVariable &GV : M.globals())
2134     if (GV.hasMetadata())
2135       AddDeclAttachedMetadata(GV);
2136 
2137   Stream.ExitBlock();
2138 }
2139 
2140 void ModuleBitcodeWriter::writeFunctionMetadata(const Function &F) {
2141   if (!VE.hasMDs())
2142     return;
2143 
2144   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
2145   SmallVector<uint64_t, 64> Record;
2146   writeMetadataStrings(VE.getMDStrings(), Record);
2147   writeMetadataRecords(VE.getNonMDStrings(), Record);
2148   Stream.ExitBlock();
2149 }
2150 
2151 void ModuleBitcodeWriter::pushGlobalMetadataAttachment(
2152     SmallVectorImpl<uint64_t> &Record, const GlobalObject &GO) {
2153   // [n x [id, mdnode]]
2154   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2155   GO.getAllMetadata(MDs);
2156   for (const auto &I : MDs) {
2157     Record.push_back(I.first);
2158     Record.push_back(VE.getMetadataID(I.second));
2159   }
2160 }
2161 
2162 void ModuleBitcodeWriter::writeFunctionMetadataAttachment(const Function &F) {
2163   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
2164 
2165   SmallVector<uint64_t, 64> Record;
2166 
2167   if (F.hasMetadata()) {
2168     pushGlobalMetadataAttachment(Record, F);
2169     Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2170     Record.clear();
2171   }
2172 
2173   // Write metadata attachments
2174   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
2175   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2176   for (const BasicBlock &BB : F)
2177     for (const Instruction &I : BB) {
2178       MDs.clear();
2179       I.getAllMetadataOtherThanDebugLoc(MDs);
2180 
2181       // If no metadata, ignore instruction.
2182       if (MDs.empty()) continue;
2183 
2184       Record.push_back(VE.getInstructionID(&I));
2185 
2186       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
2187         Record.push_back(MDs[i].first);
2188         Record.push_back(VE.getMetadataID(MDs[i].second));
2189       }
2190       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2191       Record.clear();
2192     }
2193 
2194   Stream.ExitBlock();
2195 }
2196 
2197 void ModuleBitcodeWriter::writeModuleMetadataKinds() {
2198   SmallVector<uint64_t, 64> Record;
2199 
2200   // Write metadata kinds
2201   // METADATA_KIND - [n x [id, name]]
2202   SmallVector<StringRef, 8> Names;
2203   M.getMDKindNames(Names);
2204 
2205   if (Names.empty()) return;
2206 
2207   Stream.EnterSubblock(bitc::METADATA_KIND_BLOCK_ID, 3);
2208 
2209   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
2210     Record.push_back(MDKindID);
2211     StringRef KName = Names[MDKindID];
2212     Record.append(KName.begin(), KName.end());
2213 
2214     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
2215     Record.clear();
2216   }
2217 
2218   Stream.ExitBlock();
2219 }
2220 
2221 void ModuleBitcodeWriter::writeOperandBundleTags() {
2222   // Write metadata kinds
2223   //
2224   // OPERAND_BUNDLE_TAGS_BLOCK_ID : N x OPERAND_BUNDLE_TAG
2225   //
2226   // OPERAND_BUNDLE_TAG - [strchr x N]
2227 
2228   SmallVector<StringRef, 8> Tags;
2229   M.getOperandBundleTags(Tags);
2230 
2231   if (Tags.empty())
2232     return;
2233 
2234   Stream.EnterSubblock(bitc::OPERAND_BUNDLE_TAGS_BLOCK_ID, 3);
2235 
2236   SmallVector<uint64_t, 64> Record;
2237 
2238   for (auto Tag : Tags) {
2239     Record.append(Tag.begin(), Tag.end());
2240 
2241     Stream.EmitRecord(bitc::OPERAND_BUNDLE_TAG, Record, 0);
2242     Record.clear();
2243   }
2244 
2245   Stream.ExitBlock();
2246 }
2247 
2248 void ModuleBitcodeWriter::writeSyncScopeNames() {
2249   SmallVector<StringRef, 8> SSNs;
2250   M.getContext().getSyncScopeNames(SSNs);
2251   if (SSNs.empty())
2252     return;
2253 
2254   Stream.EnterSubblock(bitc::SYNC_SCOPE_NAMES_BLOCK_ID, 2);
2255 
2256   SmallVector<uint64_t, 64> Record;
2257   for (auto SSN : SSNs) {
2258     Record.append(SSN.begin(), SSN.end());
2259     Stream.EmitRecord(bitc::SYNC_SCOPE_NAME, Record, 0);
2260     Record.clear();
2261   }
2262 
2263   Stream.ExitBlock();
2264 }
2265 
2266 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
2267   if ((int64_t)V >= 0)
2268     Vals.push_back(V << 1);
2269   else
2270     Vals.push_back((-V << 1) | 1);
2271 }
2272 
2273 void ModuleBitcodeWriter::writeConstants(unsigned FirstVal, unsigned LastVal,
2274                                          bool isGlobal) {
2275   if (FirstVal == LastVal) return;
2276 
2277   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
2278 
2279   unsigned AggregateAbbrev = 0;
2280   unsigned String8Abbrev = 0;
2281   unsigned CString7Abbrev = 0;
2282   unsigned CString6Abbrev = 0;
2283   // If this is a constant pool for the module, emit module-specific abbrevs.
2284   if (isGlobal) {
2285     // Abbrev for CST_CODE_AGGREGATE.
2286     auto Abbv = std::make_shared<BitCodeAbbrev>();
2287     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
2288     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2289     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
2290     AggregateAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2291 
2292     // Abbrev for CST_CODE_STRING.
2293     Abbv = std::make_shared<BitCodeAbbrev>();
2294     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
2295     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2296     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2297     String8Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2298     // Abbrev for CST_CODE_CSTRING.
2299     Abbv = std::make_shared<BitCodeAbbrev>();
2300     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2301     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2302     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2303     CString7Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2304     // Abbrev for CST_CODE_CSTRING.
2305     Abbv = std::make_shared<BitCodeAbbrev>();
2306     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2307     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2308     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2309     CString6Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2310   }
2311 
2312   SmallVector<uint64_t, 64> Record;
2313 
2314   const ValueEnumerator::ValueList &Vals = VE.getValues();
2315   Type *LastTy = nullptr;
2316   for (unsigned i = FirstVal; i != LastVal; ++i) {
2317     const Value *V = Vals[i].first;
2318     // If we need to switch types, do so now.
2319     if (V->getType() != LastTy) {
2320       LastTy = V->getType();
2321       Record.push_back(VE.getTypeID(LastTy));
2322       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
2323                         CONSTANTS_SETTYPE_ABBREV);
2324       Record.clear();
2325     }
2326 
2327     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
2328       Record.push_back(unsigned(IA->hasSideEffects()) |
2329                        unsigned(IA->isAlignStack()) << 1 |
2330                        unsigned(IA->getDialect()&1) << 2);
2331 
2332       // Add the asm string.
2333       const std::string &AsmStr = IA->getAsmString();
2334       Record.push_back(AsmStr.size());
2335       Record.append(AsmStr.begin(), AsmStr.end());
2336 
2337       // Add the constraint string.
2338       const std::string &ConstraintStr = IA->getConstraintString();
2339       Record.push_back(ConstraintStr.size());
2340       Record.append(ConstraintStr.begin(), ConstraintStr.end());
2341       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
2342       Record.clear();
2343       continue;
2344     }
2345     const Constant *C = cast<Constant>(V);
2346     unsigned Code = -1U;
2347     unsigned AbbrevToUse = 0;
2348     if (C->isNullValue()) {
2349       Code = bitc::CST_CODE_NULL;
2350     } else if (isa<UndefValue>(C)) {
2351       Code = bitc::CST_CODE_UNDEF;
2352     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
2353       if (IV->getBitWidth() <= 64) {
2354         uint64_t V = IV->getSExtValue();
2355         emitSignedInt64(Record, V);
2356         Code = bitc::CST_CODE_INTEGER;
2357         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
2358       } else {                             // Wide integers, > 64 bits in size.
2359         // We have an arbitrary precision integer value to write whose
2360         // bit width is > 64. However, in canonical unsigned integer
2361         // format it is likely that the high bits are going to be zero.
2362         // So, we only write the number of active words.
2363         unsigned NWords = IV->getValue().getActiveWords();
2364         const uint64_t *RawWords = IV->getValue().getRawData();
2365         for (unsigned i = 0; i != NWords; ++i) {
2366           emitSignedInt64(Record, RawWords[i]);
2367         }
2368         Code = bitc::CST_CODE_WIDE_INTEGER;
2369       }
2370     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
2371       Code = bitc::CST_CODE_FLOAT;
2372       Type *Ty = CFP->getType();
2373       if (Ty->isHalfTy() || Ty->isFloatTy() || Ty->isDoubleTy()) {
2374         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
2375       } else if (Ty->isX86_FP80Ty()) {
2376         // api needed to prevent premature destruction
2377         // bits are not in the same order as a normal i80 APInt, compensate.
2378         APInt api = CFP->getValueAPF().bitcastToAPInt();
2379         const uint64_t *p = api.getRawData();
2380         Record.push_back((p[1] << 48) | (p[0] >> 16));
2381         Record.push_back(p[0] & 0xffffLL);
2382       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
2383         APInt api = CFP->getValueAPF().bitcastToAPInt();
2384         const uint64_t *p = api.getRawData();
2385         Record.push_back(p[0]);
2386         Record.push_back(p[1]);
2387       } else {
2388         assert(0 && "Unknown FP type!");
2389       }
2390     } else if (isa<ConstantDataSequential>(C) &&
2391                cast<ConstantDataSequential>(C)->isString()) {
2392       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
2393       // Emit constant strings specially.
2394       unsigned NumElts = Str->getNumElements();
2395       // If this is a null-terminated string, use the denser CSTRING encoding.
2396       if (Str->isCString()) {
2397         Code = bitc::CST_CODE_CSTRING;
2398         --NumElts;  // Don't encode the null, which isn't allowed by char6.
2399       } else {
2400         Code = bitc::CST_CODE_STRING;
2401         AbbrevToUse = String8Abbrev;
2402       }
2403       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
2404       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
2405       for (unsigned i = 0; i != NumElts; ++i) {
2406         unsigned char V = Str->getElementAsInteger(i);
2407         Record.push_back(V);
2408         isCStr7 &= (V & 128) == 0;
2409         if (isCStrChar6)
2410           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
2411       }
2412 
2413       if (isCStrChar6)
2414         AbbrevToUse = CString6Abbrev;
2415       else if (isCStr7)
2416         AbbrevToUse = CString7Abbrev;
2417     } else if (const ConstantDataSequential *CDS =
2418                   dyn_cast<ConstantDataSequential>(C)) {
2419       Code = bitc::CST_CODE_DATA;
2420       Type *EltTy = CDS->getType()->getElementType();
2421       if (isa<IntegerType>(EltTy)) {
2422         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2423           Record.push_back(CDS->getElementAsInteger(i));
2424       } else {
2425         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2426           Record.push_back(
2427               CDS->getElementAsAPFloat(i).bitcastToAPInt().getLimitedValue());
2428       }
2429     } else if (isa<ConstantAggregate>(C)) {
2430       Code = bitc::CST_CODE_AGGREGATE;
2431       for (const Value *Op : C->operands())
2432         Record.push_back(VE.getValueID(Op));
2433       AbbrevToUse = AggregateAbbrev;
2434     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
2435       switch (CE->getOpcode()) {
2436       default:
2437         if (Instruction::isCast(CE->getOpcode())) {
2438           Code = bitc::CST_CODE_CE_CAST;
2439           Record.push_back(getEncodedCastOpcode(CE->getOpcode()));
2440           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2441           Record.push_back(VE.getValueID(C->getOperand(0)));
2442           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
2443         } else {
2444           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
2445           Code = bitc::CST_CODE_CE_BINOP;
2446           Record.push_back(getEncodedBinaryOpcode(CE->getOpcode()));
2447           Record.push_back(VE.getValueID(C->getOperand(0)));
2448           Record.push_back(VE.getValueID(C->getOperand(1)));
2449           uint64_t Flags = getOptimizationFlags(CE);
2450           if (Flags != 0)
2451             Record.push_back(Flags);
2452         }
2453         break;
2454       case Instruction::FNeg: {
2455         assert(CE->getNumOperands() == 1 && "Unknown constant expr!");
2456         Code = bitc::CST_CODE_CE_UNOP;
2457         Record.push_back(getEncodedUnaryOpcode(CE->getOpcode()));
2458         Record.push_back(VE.getValueID(C->getOperand(0)));
2459         uint64_t Flags = getOptimizationFlags(CE);
2460         if (Flags != 0)
2461           Record.push_back(Flags);
2462         break;
2463       }
2464       case Instruction::GetElementPtr: {
2465         Code = bitc::CST_CODE_CE_GEP;
2466         const auto *GO = cast<GEPOperator>(C);
2467         Record.push_back(VE.getTypeID(GO->getSourceElementType()));
2468         if (Optional<unsigned> Idx = GO->getInRangeIndex()) {
2469           Code = bitc::CST_CODE_CE_GEP_WITH_INRANGE_INDEX;
2470           Record.push_back((*Idx << 1) | GO->isInBounds());
2471         } else if (GO->isInBounds())
2472           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
2473         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
2474           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
2475           Record.push_back(VE.getValueID(C->getOperand(i)));
2476         }
2477         break;
2478       }
2479       case Instruction::Select:
2480         Code = bitc::CST_CODE_CE_SELECT;
2481         Record.push_back(VE.getValueID(C->getOperand(0)));
2482         Record.push_back(VE.getValueID(C->getOperand(1)));
2483         Record.push_back(VE.getValueID(C->getOperand(2)));
2484         break;
2485       case Instruction::ExtractElement:
2486         Code = bitc::CST_CODE_CE_EXTRACTELT;
2487         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2488         Record.push_back(VE.getValueID(C->getOperand(0)));
2489         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
2490         Record.push_back(VE.getValueID(C->getOperand(1)));
2491         break;
2492       case Instruction::InsertElement:
2493         Code = bitc::CST_CODE_CE_INSERTELT;
2494         Record.push_back(VE.getValueID(C->getOperand(0)));
2495         Record.push_back(VE.getValueID(C->getOperand(1)));
2496         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
2497         Record.push_back(VE.getValueID(C->getOperand(2)));
2498         break;
2499       case Instruction::ShuffleVector:
2500         // If the return type and argument types are the same, this is a
2501         // standard shufflevector instruction.  If the types are different,
2502         // then the shuffle is widening or truncating the input vectors, and
2503         // the argument type must also be encoded.
2504         if (C->getType() == C->getOperand(0)->getType()) {
2505           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
2506         } else {
2507           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
2508           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2509         }
2510         Record.push_back(VE.getValueID(C->getOperand(0)));
2511         Record.push_back(VE.getValueID(C->getOperand(1)));
2512         Record.push_back(VE.getValueID(C->getOperand(2)));
2513         break;
2514       case Instruction::ICmp:
2515       case Instruction::FCmp:
2516         Code = bitc::CST_CODE_CE_CMP;
2517         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2518         Record.push_back(VE.getValueID(C->getOperand(0)));
2519         Record.push_back(VE.getValueID(C->getOperand(1)));
2520         Record.push_back(CE->getPredicate());
2521         break;
2522       }
2523     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
2524       Code = bitc::CST_CODE_BLOCKADDRESS;
2525       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
2526       Record.push_back(VE.getValueID(BA->getFunction()));
2527       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
2528     } else {
2529 #ifndef NDEBUG
2530       C->dump();
2531 #endif
2532       llvm_unreachable("Unknown constant!");
2533     }
2534     Stream.EmitRecord(Code, Record, AbbrevToUse);
2535     Record.clear();
2536   }
2537 
2538   Stream.ExitBlock();
2539 }
2540 
2541 void ModuleBitcodeWriter::writeModuleConstants() {
2542   const ValueEnumerator::ValueList &Vals = VE.getValues();
2543 
2544   // Find the first constant to emit, which is the first non-globalvalue value.
2545   // We know globalvalues have been emitted by WriteModuleInfo.
2546   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
2547     if (!isa<GlobalValue>(Vals[i].first)) {
2548       writeConstants(i, Vals.size(), true);
2549       return;
2550     }
2551   }
2552 }
2553 
2554 /// pushValueAndType - The file has to encode both the value and type id for
2555 /// many values, because we need to know what type to create for forward
2556 /// references.  However, most operands are not forward references, so this type
2557 /// field is not needed.
2558 ///
2559 /// This function adds V's value ID to Vals.  If the value ID is higher than the
2560 /// instruction ID, then it is a forward reference, and it also includes the
2561 /// type ID.  The value ID that is written is encoded relative to the InstID.
2562 bool ModuleBitcodeWriter::pushValueAndType(const Value *V, unsigned InstID,
2563                                            SmallVectorImpl<unsigned> &Vals) {
2564   unsigned ValID = VE.getValueID(V);
2565   // Make encoding relative to the InstID.
2566   Vals.push_back(InstID - ValID);
2567   if (ValID >= InstID) {
2568     Vals.push_back(VE.getTypeID(V->getType()));
2569     return true;
2570   }
2571   return false;
2572 }
2573 
2574 void ModuleBitcodeWriter::writeOperandBundles(ImmutableCallSite CS,
2575                                               unsigned InstID) {
2576   SmallVector<unsigned, 64> Record;
2577   LLVMContext &C = CS.getInstruction()->getContext();
2578 
2579   for (unsigned i = 0, e = CS.getNumOperandBundles(); i != e; ++i) {
2580     const auto &Bundle = CS.getOperandBundleAt(i);
2581     Record.push_back(C.getOperandBundleTagID(Bundle.getTagName()));
2582 
2583     for (auto &Input : Bundle.Inputs)
2584       pushValueAndType(Input, InstID, Record);
2585 
2586     Stream.EmitRecord(bitc::FUNC_CODE_OPERAND_BUNDLE, Record);
2587     Record.clear();
2588   }
2589 }
2590 
2591 /// pushValue - Like pushValueAndType, but where the type of the value is
2592 /// omitted (perhaps it was already encoded in an earlier operand).
2593 void ModuleBitcodeWriter::pushValue(const Value *V, unsigned InstID,
2594                                     SmallVectorImpl<unsigned> &Vals) {
2595   unsigned ValID = VE.getValueID(V);
2596   Vals.push_back(InstID - ValID);
2597 }
2598 
2599 void ModuleBitcodeWriter::pushValueSigned(const Value *V, unsigned InstID,
2600                                           SmallVectorImpl<uint64_t> &Vals) {
2601   unsigned ValID = VE.getValueID(V);
2602   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
2603   emitSignedInt64(Vals, diff);
2604 }
2605 
2606 /// WriteInstruction - Emit an instruction to the specified stream.
2607 void ModuleBitcodeWriter::writeInstruction(const Instruction &I,
2608                                            unsigned InstID,
2609                                            SmallVectorImpl<unsigned> &Vals) {
2610   unsigned Code = 0;
2611   unsigned AbbrevToUse = 0;
2612   VE.setInstructionID(&I);
2613   switch (I.getOpcode()) {
2614   default:
2615     if (Instruction::isCast(I.getOpcode())) {
2616       Code = bitc::FUNC_CODE_INST_CAST;
2617       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2618         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
2619       Vals.push_back(VE.getTypeID(I.getType()));
2620       Vals.push_back(getEncodedCastOpcode(I.getOpcode()));
2621     } else {
2622       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
2623       Code = bitc::FUNC_CODE_INST_BINOP;
2624       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2625         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
2626       pushValue(I.getOperand(1), InstID, Vals);
2627       Vals.push_back(getEncodedBinaryOpcode(I.getOpcode()));
2628       uint64_t Flags = getOptimizationFlags(&I);
2629       if (Flags != 0) {
2630         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
2631           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
2632         Vals.push_back(Flags);
2633       }
2634     }
2635     break;
2636   case Instruction::FNeg: {
2637     Code = bitc::FUNC_CODE_INST_UNOP;
2638     if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2639       AbbrevToUse = FUNCTION_INST_UNOP_ABBREV;
2640     Vals.push_back(getEncodedUnaryOpcode(I.getOpcode()));
2641     uint64_t Flags = getOptimizationFlags(&I);
2642     if (Flags != 0) {
2643       if (AbbrevToUse == FUNCTION_INST_UNOP_ABBREV)
2644         AbbrevToUse = FUNCTION_INST_UNOP_FLAGS_ABBREV;
2645       Vals.push_back(Flags);
2646     }
2647     break;
2648   }
2649   case Instruction::GetElementPtr: {
2650     Code = bitc::FUNC_CODE_INST_GEP;
2651     AbbrevToUse = FUNCTION_INST_GEP_ABBREV;
2652     auto &GEPInst = cast<GetElementPtrInst>(I);
2653     Vals.push_back(GEPInst.isInBounds());
2654     Vals.push_back(VE.getTypeID(GEPInst.getSourceElementType()));
2655     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
2656       pushValueAndType(I.getOperand(i), InstID, Vals);
2657     break;
2658   }
2659   case Instruction::ExtractValue: {
2660     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
2661     pushValueAndType(I.getOperand(0), InstID, Vals);
2662     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
2663     Vals.append(EVI->idx_begin(), EVI->idx_end());
2664     break;
2665   }
2666   case Instruction::InsertValue: {
2667     Code = bitc::FUNC_CODE_INST_INSERTVAL;
2668     pushValueAndType(I.getOperand(0), InstID, Vals);
2669     pushValueAndType(I.getOperand(1), InstID, Vals);
2670     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
2671     Vals.append(IVI->idx_begin(), IVI->idx_end());
2672     break;
2673   }
2674   case Instruction::Select: {
2675     Code = bitc::FUNC_CODE_INST_VSELECT;
2676     pushValueAndType(I.getOperand(1), InstID, Vals);
2677     pushValue(I.getOperand(2), InstID, Vals);
2678     pushValueAndType(I.getOperand(0), InstID, Vals);
2679     uint64_t Flags = getOptimizationFlags(&I);
2680     if (Flags != 0)
2681       Vals.push_back(Flags);
2682     break;
2683   }
2684   case Instruction::ExtractElement:
2685     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
2686     pushValueAndType(I.getOperand(0), InstID, Vals);
2687     pushValueAndType(I.getOperand(1), InstID, Vals);
2688     break;
2689   case Instruction::InsertElement:
2690     Code = bitc::FUNC_CODE_INST_INSERTELT;
2691     pushValueAndType(I.getOperand(0), InstID, Vals);
2692     pushValue(I.getOperand(1), InstID, Vals);
2693     pushValueAndType(I.getOperand(2), InstID, Vals);
2694     break;
2695   case Instruction::ShuffleVector:
2696     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
2697     pushValueAndType(I.getOperand(0), InstID, Vals);
2698     pushValue(I.getOperand(1), InstID, Vals);
2699     pushValue(I.getOperand(2), InstID, Vals);
2700     break;
2701   case Instruction::ICmp:
2702   case Instruction::FCmp: {
2703     // compare returning Int1Ty or vector of Int1Ty
2704     Code = bitc::FUNC_CODE_INST_CMP2;
2705     pushValueAndType(I.getOperand(0), InstID, Vals);
2706     pushValue(I.getOperand(1), InstID, Vals);
2707     Vals.push_back(cast<CmpInst>(I).getPredicate());
2708     uint64_t Flags = getOptimizationFlags(&I);
2709     if (Flags != 0)
2710       Vals.push_back(Flags);
2711     break;
2712   }
2713 
2714   case Instruction::Ret:
2715     {
2716       Code = bitc::FUNC_CODE_INST_RET;
2717       unsigned NumOperands = I.getNumOperands();
2718       if (NumOperands == 0)
2719         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
2720       else if (NumOperands == 1) {
2721         if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2722           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
2723       } else {
2724         for (unsigned i = 0, e = NumOperands; i != e; ++i)
2725           pushValueAndType(I.getOperand(i), InstID, Vals);
2726       }
2727     }
2728     break;
2729   case Instruction::Br:
2730     {
2731       Code = bitc::FUNC_CODE_INST_BR;
2732       const BranchInst &II = cast<BranchInst>(I);
2733       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
2734       if (II.isConditional()) {
2735         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
2736         pushValue(II.getCondition(), InstID, Vals);
2737       }
2738     }
2739     break;
2740   case Instruction::Switch:
2741     {
2742       Code = bitc::FUNC_CODE_INST_SWITCH;
2743       const SwitchInst &SI = cast<SwitchInst>(I);
2744       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
2745       pushValue(SI.getCondition(), InstID, Vals);
2746       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
2747       for (auto Case : SI.cases()) {
2748         Vals.push_back(VE.getValueID(Case.getCaseValue()));
2749         Vals.push_back(VE.getValueID(Case.getCaseSuccessor()));
2750       }
2751     }
2752     break;
2753   case Instruction::IndirectBr:
2754     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
2755     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2756     // Encode the address operand as relative, but not the basic blocks.
2757     pushValue(I.getOperand(0), InstID, Vals);
2758     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
2759       Vals.push_back(VE.getValueID(I.getOperand(i)));
2760     break;
2761 
2762   case Instruction::Invoke: {
2763     const InvokeInst *II = cast<InvokeInst>(&I);
2764     const Value *Callee = II->getCalledValue();
2765     FunctionType *FTy = II->getFunctionType();
2766 
2767     if (II->hasOperandBundles())
2768       writeOperandBundles(II, InstID);
2769 
2770     Code = bitc::FUNC_CODE_INST_INVOKE;
2771 
2772     Vals.push_back(VE.getAttributeListID(II->getAttributes()));
2773     Vals.push_back(II->getCallingConv() | 1 << 13);
2774     Vals.push_back(VE.getValueID(II->getNormalDest()));
2775     Vals.push_back(VE.getValueID(II->getUnwindDest()));
2776     Vals.push_back(VE.getTypeID(FTy));
2777     pushValueAndType(Callee, InstID, Vals);
2778 
2779     // Emit value #'s for the fixed parameters.
2780     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
2781       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
2782 
2783     // Emit type/value pairs for varargs params.
2784     if (FTy->isVarArg()) {
2785       for (unsigned i = FTy->getNumParams(), e = II->getNumArgOperands();
2786            i != e; ++i)
2787         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
2788     }
2789     break;
2790   }
2791   case Instruction::Resume:
2792     Code = bitc::FUNC_CODE_INST_RESUME;
2793     pushValueAndType(I.getOperand(0), InstID, Vals);
2794     break;
2795   case Instruction::CleanupRet: {
2796     Code = bitc::FUNC_CODE_INST_CLEANUPRET;
2797     const auto &CRI = cast<CleanupReturnInst>(I);
2798     pushValue(CRI.getCleanupPad(), InstID, Vals);
2799     if (CRI.hasUnwindDest())
2800       Vals.push_back(VE.getValueID(CRI.getUnwindDest()));
2801     break;
2802   }
2803   case Instruction::CatchRet: {
2804     Code = bitc::FUNC_CODE_INST_CATCHRET;
2805     const auto &CRI = cast<CatchReturnInst>(I);
2806     pushValue(CRI.getCatchPad(), InstID, Vals);
2807     Vals.push_back(VE.getValueID(CRI.getSuccessor()));
2808     break;
2809   }
2810   case Instruction::CleanupPad:
2811   case Instruction::CatchPad: {
2812     const auto &FuncletPad = cast<FuncletPadInst>(I);
2813     Code = isa<CatchPadInst>(FuncletPad) ? bitc::FUNC_CODE_INST_CATCHPAD
2814                                          : bitc::FUNC_CODE_INST_CLEANUPPAD;
2815     pushValue(FuncletPad.getParentPad(), InstID, Vals);
2816 
2817     unsigned NumArgOperands = FuncletPad.getNumArgOperands();
2818     Vals.push_back(NumArgOperands);
2819     for (unsigned Op = 0; Op != NumArgOperands; ++Op)
2820       pushValueAndType(FuncletPad.getArgOperand(Op), InstID, Vals);
2821     break;
2822   }
2823   case Instruction::CatchSwitch: {
2824     Code = bitc::FUNC_CODE_INST_CATCHSWITCH;
2825     const auto &CatchSwitch = cast<CatchSwitchInst>(I);
2826 
2827     pushValue(CatchSwitch.getParentPad(), InstID, Vals);
2828 
2829     unsigned NumHandlers = CatchSwitch.getNumHandlers();
2830     Vals.push_back(NumHandlers);
2831     for (const BasicBlock *CatchPadBB : CatchSwitch.handlers())
2832       Vals.push_back(VE.getValueID(CatchPadBB));
2833 
2834     if (CatchSwitch.hasUnwindDest())
2835       Vals.push_back(VE.getValueID(CatchSwitch.getUnwindDest()));
2836     break;
2837   }
2838   case Instruction::CallBr: {
2839     const CallBrInst *CBI = cast<CallBrInst>(&I);
2840     const Value *Callee = CBI->getCalledValue();
2841     FunctionType *FTy = CBI->getFunctionType();
2842 
2843     if (CBI->hasOperandBundles())
2844       writeOperandBundles(CBI, InstID);
2845 
2846     Code = bitc::FUNC_CODE_INST_CALLBR;
2847 
2848     Vals.push_back(VE.getAttributeListID(CBI->getAttributes()));
2849 
2850     Vals.push_back(CBI->getCallingConv() << bitc::CALL_CCONV |
2851                    1 << bitc::CALL_EXPLICIT_TYPE);
2852 
2853     Vals.push_back(VE.getValueID(CBI->getDefaultDest()));
2854     Vals.push_back(CBI->getNumIndirectDests());
2855     for (unsigned i = 0, e = CBI->getNumIndirectDests(); i != e; ++i)
2856       Vals.push_back(VE.getValueID(CBI->getIndirectDest(i)));
2857 
2858     Vals.push_back(VE.getTypeID(FTy));
2859     pushValueAndType(Callee, InstID, Vals);
2860 
2861     // Emit value #'s for the fixed parameters.
2862     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
2863       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
2864 
2865     // Emit type/value pairs for varargs params.
2866     if (FTy->isVarArg()) {
2867       for (unsigned i = FTy->getNumParams(), e = CBI->getNumArgOperands();
2868            i != e; ++i)
2869         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
2870     }
2871     break;
2872   }
2873   case Instruction::Unreachable:
2874     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
2875     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
2876     break;
2877 
2878   case Instruction::PHI: {
2879     const PHINode &PN = cast<PHINode>(I);
2880     Code = bitc::FUNC_CODE_INST_PHI;
2881     // With the newer instruction encoding, forward references could give
2882     // negative valued IDs.  This is most common for PHIs, so we use
2883     // signed VBRs.
2884     SmallVector<uint64_t, 128> Vals64;
2885     Vals64.push_back(VE.getTypeID(PN.getType()));
2886     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
2887       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64);
2888       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
2889     }
2890 
2891     uint64_t Flags = getOptimizationFlags(&I);
2892     if (Flags != 0)
2893       Vals64.push_back(Flags);
2894 
2895     // Emit a Vals64 vector and exit.
2896     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
2897     Vals64.clear();
2898     return;
2899   }
2900 
2901   case Instruction::LandingPad: {
2902     const LandingPadInst &LP = cast<LandingPadInst>(I);
2903     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
2904     Vals.push_back(VE.getTypeID(LP.getType()));
2905     Vals.push_back(LP.isCleanup());
2906     Vals.push_back(LP.getNumClauses());
2907     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
2908       if (LP.isCatch(I))
2909         Vals.push_back(LandingPadInst::Catch);
2910       else
2911         Vals.push_back(LandingPadInst::Filter);
2912       pushValueAndType(LP.getClause(I), InstID, Vals);
2913     }
2914     break;
2915   }
2916 
2917   case Instruction::Alloca: {
2918     Code = bitc::FUNC_CODE_INST_ALLOCA;
2919     const AllocaInst &AI = cast<AllocaInst>(I);
2920     Vals.push_back(VE.getTypeID(AI.getAllocatedType()));
2921     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2922     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
2923     unsigned AlignRecord = Log2_32(AI.getAlignment()) + 1;
2924     assert(Log2_32(Value::MaximumAlignment) + 1 < 1 << 5 &&
2925            "not enough bits for maximum alignment");
2926     assert(AlignRecord < 1 << 5 && "alignment greater than 1 << 64");
2927     AlignRecord |= AI.isUsedWithInAlloca() << 5;
2928     AlignRecord |= 1 << 6;
2929     AlignRecord |= AI.isSwiftError() << 7;
2930     Vals.push_back(AlignRecord);
2931     break;
2932   }
2933 
2934   case Instruction::Load:
2935     if (cast<LoadInst>(I).isAtomic()) {
2936       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
2937       pushValueAndType(I.getOperand(0), InstID, Vals);
2938     } else {
2939       Code = bitc::FUNC_CODE_INST_LOAD;
2940       if (!pushValueAndType(I.getOperand(0), InstID, Vals)) // ptr
2941         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
2942     }
2943     Vals.push_back(VE.getTypeID(I.getType()));
2944     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
2945     Vals.push_back(cast<LoadInst>(I).isVolatile());
2946     if (cast<LoadInst>(I).isAtomic()) {
2947       Vals.push_back(getEncodedOrdering(cast<LoadInst>(I).getOrdering()));
2948       Vals.push_back(getEncodedSyncScopeID(cast<LoadInst>(I).getSyncScopeID()));
2949     }
2950     break;
2951   case Instruction::Store:
2952     if (cast<StoreInst>(I).isAtomic())
2953       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
2954     else
2955       Code = bitc::FUNC_CODE_INST_STORE;
2956     pushValueAndType(I.getOperand(1), InstID, Vals); // ptrty + ptr
2957     pushValueAndType(I.getOperand(0), InstID, Vals); // valty + val
2958     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
2959     Vals.push_back(cast<StoreInst>(I).isVolatile());
2960     if (cast<StoreInst>(I).isAtomic()) {
2961       Vals.push_back(getEncodedOrdering(cast<StoreInst>(I).getOrdering()));
2962       Vals.push_back(
2963           getEncodedSyncScopeID(cast<StoreInst>(I).getSyncScopeID()));
2964     }
2965     break;
2966   case Instruction::AtomicCmpXchg:
2967     Code = bitc::FUNC_CODE_INST_CMPXCHG;
2968     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
2969     pushValueAndType(I.getOperand(1), InstID, Vals); // cmp.
2970     pushValue(I.getOperand(2), InstID, Vals);        // newval.
2971     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
2972     Vals.push_back(
2973         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
2974     Vals.push_back(
2975         getEncodedSyncScopeID(cast<AtomicCmpXchgInst>(I).getSyncScopeID()));
2976     Vals.push_back(
2977         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
2978     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
2979     break;
2980   case Instruction::AtomicRMW:
2981     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
2982     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
2983     pushValue(I.getOperand(1), InstID, Vals);        // val.
2984     Vals.push_back(
2985         getEncodedRMWOperation(cast<AtomicRMWInst>(I).getOperation()));
2986     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
2987     Vals.push_back(getEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
2988     Vals.push_back(
2989         getEncodedSyncScopeID(cast<AtomicRMWInst>(I).getSyncScopeID()));
2990     break;
2991   case Instruction::Fence:
2992     Code = bitc::FUNC_CODE_INST_FENCE;
2993     Vals.push_back(getEncodedOrdering(cast<FenceInst>(I).getOrdering()));
2994     Vals.push_back(getEncodedSyncScopeID(cast<FenceInst>(I).getSyncScopeID()));
2995     break;
2996   case Instruction::Call: {
2997     const CallInst &CI = cast<CallInst>(I);
2998     FunctionType *FTy = CI.getFunctionType();
2999 
3000     if (CI.hasOperandBundles())
3001       writeOperandBundles(&CI, InstID);
3002 
3003     Code = bitc::FUNC_CODE_INST_CALL;
3004 
3005     Vals.push_back(VE.getAttributeListID(CI.getAttributes()));
3006 
3007     unsigned Flags = getOptimizationFlags(&I);
3008     Vals.push_back(CI.getCallingConv() << bitc::CALL_CCONV |
3009                    unsigned(CI.isTailCall()) << bitc::CALL_TAIL |
3010                    unsigned(CI.isMustTailCall()) << bitc::CALL_MUSTTAIL |
3011                    1 << bitc::CALL_EXPLICIT_TYPE |
3012                    unsigned(CI.isNoTailCall()) << bitc::CALL_NOTAIL |
3013                    unsigned(Flags != 0) << bitc::CALL_FMF);
3014     if (Flags != 0)
3015       Vals.push_back(Flags);
3016 
3017     Vals.push_back(VE.getTypeID(FTy));
3018     pushValueAndType(CI.getCalledValue(), InstID, Vals); // Callee
3019 
3020     // Emit value #'s for the fixed parameters.
3021     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
3022       // Check for labels (can happen with asm labels).
3023       if (FTy->getParamType(i)->isLabelTy())
3024         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
3025       else
3026         pushValue(CI.getArgOperand(i), InstID, Vals); // fixed param.
3027     }
3028 
3029     // Emit type/value pairs for varargs params.
3030     if (FTy->isVarArg()) {
3031       for (unsigned i = FTy->getNumParams(), e = CI.getNumArgOperands();
3032            i != e; ++i)
3033         pushValueAndType(CI.getArgOperand(i), InstID, Vals); // varargs
3034     }
3035     break;
3036   }
3037   case Instruction::VAArg:
3038     Code = bitc::FUNC_CODE_INST_VAARG;
3039     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
3040     pushValue(I.getOperand(0), InstID, Vals);                   // valist.
3041     Vals.push_back(VE.getTypeID(I.getType())); // restype.
3042     break;
3043   case Instruction::Freeze:
3044     Code = bitc::FUNC_CODE_INST_FREEZE;
3045     pushValueAndType(I.getOperand(0), InstID, Vals);
3046     break;
3047   }
3048 
3049   Stream.EmitRecord(Code, Vals, AbbrevToUse);
3050   Vals.clear();
3051 }
3052 
3053 /// Write a GlobalValue VST to the module. The purpose of this data structure is
3054 /// to allow clients to efficiently find the function body.
3055 void ModuleBitcodeWriter::writeGlobalValueSymbolTable(
3056   DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3057   // Get the offset of the VST we are writing, and backpatch it into
3058   // the VST forward declaration record.
3059   uint64_t VSTOffset = Stream.GetCurrentBitNo();
3060   // The BitcodeStartBit was the stream offset of the identification block.
3061   VSTOffset -= bitcodeStartBit();
3062   assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
3063   // Note that we add 1 here because the offset is relative to one word
3064   // before the start of the identification block, which was historically
3065   // always the start of the regular bitcode header.
3066   Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32 + 1);
3067 
3068   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3069 
3070   auto Abbv = std::make_shared<BitCodeAbbrev>();
3071   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
3072   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
3073   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
3074   unsigned FnEntryAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3075 
3076   for (const Function &F : M) {
3077     uint64_t Record[2];
3078 
3079     if (F.isDeclaration())
3080       continue;
3081 
3082     Record[0] = VE.getValueID(&F);
3083 
3084     // Save the word offset of the function (from the start of the
3085     // actual bitcode written to the stream).
3086     uint64_t BitcodeIndex = FunctionToBitcodeIndex[&F] - bitcodeStartBit();
3087     assert((BitcodeIndex & 31) == 0 && "function block not 32-bit aligned");
3088     // Note that we add 1 here because the offset is relative to one word
3089     // before the start of the identification block, which was historically
3090     // always the start of the regular bitcode header.
3091     Record[1] = BitcodeIndex / 32 + 1;
3092 
3093     Stream.EmitRecord(bitc::VST_CODE_FNENTRY, Record, FnEntryAbbrev);
3094   }
3095 
3096   Stream.ExitBlock();
3097 }
3098 
3099 /// Emit names for arguments, instructions and basic blocks in a function.
3100 void ModuleBitcodeWriter::writeFunctionLevelValueSymbolTable(
3101     const ValueSymbolTable &VST) {
3102   if (VST.empty())
3103     return;
3104 
3105   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3106 
3107   // FIXME: Set up the abbrev, we know how many values there are!
3108   // FIXME: We know if the type names can use 7-bit ascii.
3109   SmallVector<uint64_t, 64> NameVals;
3110 
3111   for (const ValueName &Name : VST) {
3112     // Figure out the encoding to use for the name.
3113     StringEncoding Bits = getStringEncoding(Name.getKey());
3114 
3115     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
3116     NameVals.push_back(VE.getValueID(Name.getValue()));
3117 
3118     // VST_CODE_ENTRY:   [valueid, namechar x N]
3119     // VST_CODE_BBENTRY: [bbid, namechar x N]
3120     unsigned Code;
3121     if (isa<BasicBlock>(Name.getValue())) {
3122       Code = bitc::VST_CODE_BBENTRY;
3123       if (Bits == SE_Char6)
3124         AbbrevToUse = VST_BBENTRY_6_ABBREV;
3125     } else {
3126       Code = bitc::VST_CODE_ENTRY;
3127       if (Bits == SE_Char6)
3128         AbbrevToUse = VST_ENTRY_6_ABBREV;
3129       else if (Bits == SE_Fixed7)
3130         AbbrevToUse = VST_ENTRY_7_ABBREV;
3131     }
3132 
3133     for (const auto P : Name.getKey())
3134       NameVals.push_back((unsigned char)P);
3135 
3136     // Emit the finished record.
3137     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
3138     NameVals.clear();
3139   }
3140 
3141   Stream.ExitBlock();
3142 }
3143 
3144 void ModuleBitcodeWriter::writeUseList(UseListOrder &&Order) {
3145   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
3146   unsigned Code;
3147   if (isa<BasicBlock>(Order.V))
3148     Code = bitc::USELIST_CODE_BB;
3149   else
3150     Code = bitc::USELIST_CODE_DEFAULT;
3151 
3152   SmallVector<uint64_t, 64> Record(Order.Shuffle.begin(), Order.Shuffle.end());
3153   Record.push_back(VE.getValueID(Order.V));
3154   Stream.EmitRecord(Code, Record);
3155 }
3156 
3157 void ModuleBitcodeWriter::writeUseListBlock(const Function *F) {
3158   assert(VE.shouldPreserveUseListOrder() &&
3159          "Expected to be preserving use-list order");
3160 
3161   auto hasMore = [&]() {
3162     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
3163   };
3164   if (!hasMore())
3165     // Nothing to do.
3166     return;
3167 
3168   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
3169   while (hasMore()) {
3170     writeUseList(std::move(VE.UseListOrders.back()));
3171     VE.UseListOrders.pop_back();
3172   }
3173   Stream.ExitBlock();
3174 }
3175 
3176 /// Emit a function body to the module stream.
3177 void ModuleBitcodeWriter::writeFunction(
3178     const Function &F,
3179     DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3180   // Save the bitcode index of the start of this function block for recording
3181   // in the VST.
3182   FunctionToBitcodeIndex[&F] = Stream.GetCurrentBitNo();
3183 
3184   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
3185   VE.incorporateFunction(F);
3186 
3187   SmallVector<unsigned, 64> Vals;
3188 
3189   // Emit the number of basic blocks, so the reader can create them ahead of
3190   // time.
3191   Vals.push_back(VE.getBasicBlocks().size());
3192   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
3193   Vals.clear();
3194 
3195   // If there are function-local constants, emit them now.
3196   unsigned CstStart, CstEnd;
3197   VE.getFunctionConstantRange(CstStart, CstEnd);
3198   writeConstants(CstStart, CstEnd, false);
3199 
3200   // If there is function-local metadata, emit it now.
3201   writeFunctionMetadata(F);
3202 
3203   // Keep a running idea of what the instruction ID is.
3204   unsigned InstID = CstEnd;
3205 
3206   bool NeedsMetadataAttachment = F.hasMetadata();
3207 
3208   DILocation *LastDL = nullptr;
3209   // Finally, emit all the instructions, in order.
3210   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
3211     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
3212          I != E; ++I) {
3213       writeInstruction(*I, InstID, Vals);
3214 
3215       if (!I->getType()->isVoidTy())
3216         ++InstID;
3217 
3218       // If the instruction has metadata, write a metadata attachment later.
3219       NeedsMetadataAttachment |= I->hasMetadataOtherThanDebugLoc();
3220 
3221       // If the instruction has a debug location, emit it.
3222       DILocation *DL = I->getDebugLoc();
3223       if (!DL)
3224         continue;
3225 
3226       if (DL == LastDL) {
3227         // Just repeat the same debug loc as last time.
3228         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
3229         continue;
3230       }
3231 
3232       Vals.push_back(DL->getLine());
3233       Vals.push_back(DL->getColumn());
3234       Vals.push_back(VE.getMetadataOrNullID(DL->getScope()));
3235       Vals.push_back(VE.getMetadataOrNullID(DL->getInlinedAt()));
3236       Vals.push_back(DL->isImplicitCode());
3237       Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
3238       Vals.clear();
3239 
3240       LastDL = DL;
3241     }
3242 
3243   // Emit names for all the instructions etc.
3244   if (auto *Symtab = F.getValueSymbolTable())
3245     writeFunctionLevelValueSymbolTable(*Symtab);
3246 
3247   if (NeedsMetadataAttachment)
3248     writeFunctionMetadataAttachment(F);
3249   if (VE.shouldPreserveUseListOrder())
3250     writeUseListBlock(&F);
3251   VE.purgeFunction();
3252   Stream.ExitBlock();
3253 }
3254 
3255 // Emit blockinfo, which defines the standard abbreviations etc.
3256 void ModuleBitcodeWriter::writeBlockInfo() {
3257   // We only want to emit block info records for blocks that have multiple
3258   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
3259   // Other blocks can define their abbrevs inline.
3260   Stream.EnterBlockInfoBlock();
3261 
3262   { // 8-bit fixed-width VST_CODE_ENTRY/VST_CODE_BBENTRY strings.
3263     auto Abbv = std::make_shared<BitCodeAbbrev>();
3264     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
3265     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3266     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3267     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3268     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3269         VST_ENTRY_8_ABBREV)
3270       llvm_unreachable("Unexpected abbrev ordering!");
3271   }
3272 
3273   { // 7-bit fixed width VST_CODE_ENTRY strings.
3274     auto Abbv = std::make_shared<BitCodeAbbrev>();
3275     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3276     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3277     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3278     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3279     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3280         VST_ENTRY_7_ABBREV)
3281       llvm_unreachable("Unexpected abbrev ordering!");
3282   }
3283   { // 6-bit char6 VST_CODE_ENTRY strings.
3284     auto Abbv = std::make_shared<BitCodeAbbrev>();
3285     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3286     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3287     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3288     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3289     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3290         VST_ENTRY_6_ABBREV)
3291       llvm_unreachable("Unexpected abbrev ordering!");
3292   }
3293   { // 6-bit char6 VST_CODE_BBENTRY strings.
3294     auto Abbv = std::make_shared<BitCodeAbbrev>();
3295     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
3296     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3297     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3298     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3299     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3300         VST_BBENTRY_6_ABBREV)
3301       llvm_unreachable("Unexpected abbrev ordering!");
3302   }
3303 
3304   { // SETTYPE abbrev for CONSTANTS_BLOCK.
3305     auto Abbv = std::make_shared<BitCodeAbbrev>();
3306     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
3307     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
3308                               VE.computeBitsRequiredForTypeIndicies()));
3309     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3310         CONSTANTS_SETTYPE_ABBREV)
3311       llvm_unreachable("Unexpected abbrev ordering!");
3312   }
3313 
3314   { // INTEGER abbrev for CONSTANTS_BLOCK.
3315     auto Abbv = std::make_shared<BitCodeAbbrev>();
3316     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
3317     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3318     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3319         CONSTANTS_INTEGER_ABBREV)
3320       llvm_unreachable("Unexpected abbrev ordering!");
3321   }
3322 
3323   { // CE_CAST abbrev for CONSTANTS_BLOCK.
3324     auto Abbv = std::make_shared<BitCodeAbbrev>();
3325     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
3326     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
3327     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
3328                               VE.computeBitsRequiredForTypeIndicies()));
3329     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
3330 
3331     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3332         CONSTANTS_CE_CAST_Abbrev)
3333       llvm_unreachable("Unexpected abbrev ordering!");
3334   }
3335   { // NULL abbrev for CONSTANTS_BLOCK.
3336     auto Abbv = std::make_shared<BitCodeAbbrev>();
3337     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
3338     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3339         CONSTANTS_NULL_Abbrev)
3340       llvm_unreachable("Unexpected abbrev ordering!");
3341   }
3342 
3343   // FIXME: This should only use space for first class types!
3344 
3345   { // INST_LOAD abbrev for FUNCTION_BLOCK.
3346     auto Abbv = std::make_shared<BitCodeAbbrev>();
3347     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
3348     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
3349     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
3350                               VE.computeBitsRequiredForTypeIndicies()));
3351     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
3352     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
3353     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3354         FUNCTION_INST_LOAD_ABBREV)
3355       llvm_unreachable("Unexpected abbrev ordering!");
3356   }
3357   { // INST_UNOP abbrev for FUNCTION_BLOCK.
3358     auto Abbv = std::make_shared<BitCodeAbbrev>();
3359     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3360     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3361     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3362     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3363         FUNCTION_INST_UNOP_ABBREV)
3364       llvm_unreachable("Unexpected abbrev ordering!");
3365   }
3366   { // INST_UNOP_FLAGS abbrev for FUNCTION_BLOCK.
3367     auto Abbv = std::make_shared<BitCodeAbbrev>();
3368     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3369     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3370     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3371     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3372     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3373         FUNCTION_INST_UNOP_FLAGS_ABBREV)
3374       llvm_unreachable("Unexpected abbrev ordering!");
3375   }
3376   { // INST_BINOP abbrev for FUNCTION_BLOCK.
3377     auto Abbv = std::make_shared<BitCodeAbbrev>();
3378     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3379     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3380     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3381     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3382     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3383         FUNCTION_INST_BINOP_ABBREV)
3384       llvm_unreachable("Unexpected abbrev ordering!");
3385   }
3386   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
3387     auto Abbv = std::make_shared<BitCodeAbbrev>();
3388     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3389     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3390     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3391     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3392     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3393     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3394         FUNCTION_INST_BINOP_FLAGS_ABBREV)
3395       llvm_unreachable("Unexpected abbrev ordering!");
3396   }
3397   { // INST_CAST abbrev for FUNCTION_BLOCK.
3398     auto Abbv = std::make_shared<BitCodeAbbrev>();
3399     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
3400     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
3401     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
3402                               VE.computeBitsRequiredForTypeIndicies()));
3403     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
3404     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3405         FUNCTION_INST_CAST_ABBREV)
3406       llvm_unreachable("Unexpected abbrev ordering!");
3407   }
3408 
3409   { // INST_RET abbrev for FUNCTION_BLOCK.
3410     auto Abbv = std::make_shared<BitCodeAbbrev>();
3411     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3412     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3413         FUNCTION_INST_RET_VOID_ABBREV)
3414       llvm_unreachable("Unexpected abbrev ordering!");
3415   }
3416   { // INST_RET abbrev for FUNCTION_BLOCK.
3417     auto Abbv = std::make_shared<BitCodeAbbrev>();
3418     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3419     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
3420     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3421         FUNCTION_INST_RET_VAL_ABBREV)
3422       llvm_unreachable("Unexpected abbrev ordering!");
3423   }
3424   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
3425     auto Abbv = std::make_shared<BitCodeAbbrev>();
3426     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
3427     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3428         FUNCTION_INST_UNREACHABLE_ABBREV)
3429       llvm_unreachable("Unexpected abbrev ordering!");
3430   }
3431   {
3432     auto Abbv = std::make_shared<BitCodeAbbrev>();
3433     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_GEP));
3434     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
3435     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, // dest ty
3436                               Log2_32_Ceil(VE.getTypes().size() + 1)));
3437     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3438     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
3439     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3440         FUNCTION_INST_GEP_ABBREV)
3441       llvm_unreachable("Unexpected abbrev ordering!");
3442   }
3443 
3444   Stream.ExitBlock();
3445 }
3446 
3447 /// Write the module path strings, currently only used when generating
3448 /// a combined index file.
3449 void IndexBitcodeWriter::writeModStrings() {
3450   Stream.EnterSubblock(bitc::MODULE_STRTAB_BLOCK_ID, 3);
3451 
3452   // TODO: See which abbrev sizes we actually need to emit
3453 
3454   // 8-bit fixed-width MST_ENTRY strings.
3455   auto Abbv = std::make_shared<BitCodeAbbrev>();
3456   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3457   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3458   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3459   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3460   unsigned Abbrev8Bit = Stream.EmitAbbrev(std::move(Abbv));
3461 
3462   // 7-bit fixed width MST_ENTRY strings.
3463   Abbv = std::make_shared<BitCodeAbbrev>();
3464   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3465   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3466   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3467   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3468   unsigned Abbrev7Bit = Stream.EmitAbbrev(std::move(Abbv));
3469 
3470   // 6-bit char6 MST_ENTRY strings.
3471   Abbv = std::make_shared<BitCodeAbbrev>();
3472   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3473   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3474   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3475   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3476   unsigned Abbrev6Bit = Stream.EmitAbbrev(std::move(Abbv));
3477 
3478   // Module Hash, 160 bits SHA1. Optionally, emitted after each MST_CODE_ENTRY.
3479   Abbv = std::make_shared<BitCodeAbbrev>();
3480   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_HASH));
3481   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3482   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3483   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3484   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3485   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3486   unsigned AbbrevHash = Stream.EmitAbbrev(std::move(Abbv));
3487 
3488   SmallVector<unsigned, 64> Vals;
3489   forEachModule(
3490       [&](const StringMapEntry<std::pair<uint64_t, ModuleHash>> &MPSE) {
3491         StringRef Key = MPSE.getKey();
3492         const auto &Value = MPSE.getValue();
3493         StringEncoding Bits = getStringEncoding(Key);
3494         unsigned AbbrevToUse = Abbrev8Bit;
3495         if (Bits == SE_Char6)
3496           AbbrevToUse = Abbrev6Bit;
3497         else if (Bits == SE_Fixed7)
3498           AbbrevToUse = Abbrev7Bit;
3499 
3500         Vals.push_back(Value.first);
3501         Vals.append(Key.begin(), Key.end());
3502 
3503         // Emit the finished record.
3504         Stream.EmitRecord(bitc::MST_CODE_ENTRY, Vals, AbbrevToUse);
3505 
3506         // Emit an optional hash for the module now
3507         const auto &Hash = Value.second;
3508         if (llvm::any_of(Hash, [](uint32_t H) { return H; })) {
3509           Vals.assign(Hash.begin(), Hash.end());
3510           // Emit the hash record.
3511           Stream.EmitRecord(bitc::MST_CODE_HASH, Vals, AbbrevHash);
3512         }
3513 
3514         Vals.clear();
3515       });
3516   Stream.ExitBlock();
3517 }
3518 
3519 /// Write the function type metadata related records that need to appear before
3520 /// a function summary entry (whether per-module or combined).
3521 static void writeFunctionTypeMetadataRecords(BitstreamWriter &Stream,
3522                                              FunctionSummary *FS) {
3523   if (!FS->type_tests().empty())
3524     Stream.EmitRecord(bitc::FS_TYPE_TESTS, FS->type_tests());
3525 
3526   SmallVector<uint64_t, 64> Record;
3527 
3528   auto WriteVFuncIdVec = [&](uint64_t Ty,
3529                              ArrayRef<FunctionSummary::VFuncId> VFs) {
3530     if (VFs.empty())
3531       return;
3532     Record.clear();
3533     for (auto &VF : VFs) {
3534       Record.push_back(VF.GUID);
3535       Record.push_back(VF.Offset);
3536     }
3537     Stream.EmitRecord(Ty, Record);
3538   };
3539 
3540   WriteVFuncIdVec(bitc::FS_TYPE_TEST_ASSUME_VCALLS,
3541                   FS->type_test_assume_vcalls());
3542   WriteVFuncIdVec(bitc::FS_TYPE_CHECKED_LOAD_VCALLS,
3543                   FS->type_checked_load_vcalls());
3544 
3545   auto WriteConstVCallVec = [&](uint64_t Ty,
3546                                 ArrayRef<FunctionSummary::ConstVCall> VCs) {
3547     for (auto &VC : VCs) {
3548       Record.clear();
3549       Record.push_back(VC.VFunc.GUID);
3550       Record.push_back(VC.VFunc.Offset);
3551       Record.insert(Record.end(), VC.Args.begin(), VC.Args.end());
3552       Stream.EmitRecord(Ty, Record);
3553     }
3554   };
3555 
3556   WriteConstVCallVec(bitc::FS_TYPE_TEST_ASSUME_CONST_VCALL,
3557                      FS->type_test_assume_const_vcalls());
3558   WriteConstVCallVec(bitc::FS_TYPE_CHECKED_LOAD_CONST_VCALL,
3559                      FS->type_checked_load_const_vcalls());
3560 }
3561 
3562 /// Collect type IDs from type tests used by function.
3563 static void
3564 getReferencedTypeIds(FunctionSummary *FS,
3565                      std::set<GlobalValue::GUID> &ReferencedTypeIds) {
3566   if (!FS->type_tests().empty())
3567     for (auto &TT : FS->type_tests())
3568       ReferencedTypeIds.insert(TT);
3569 
3570   auto GetReferencedTypesFromVFuncIdVec =
3571       [&](ArrayRef<FunctionSummary::VFuncId> VFs) {
3572         for (auto &VF : VFs)
3573           ReferencedTypeIds.insert(VF.GUID);
3574       };
3575 
3576   GetReferencedTypesFromVFuncIdVec(FS->type_test_assume_vcalls());
3577   GetReferencedTypesFromVFuncIdVec(FS->type_checked_load_vcalls());
3578 
3579   auto GetReferencedTypesFromConstVCallVec =
3580       [&](ArrayRef<FunctionSummary::ConstVCall> VCs) {
3581         for (auto &VC : VCs)
3582           ReferencedTypeIds.insert(VC.VFunc.GUID);
3583       };
3584 
3585   GetReferencedTypesFromConstVCallVec(FS->type_test_assume_const_vcalls());
3586   GetReferencedTypesFromConstVCallVec(FS->type_checked_load_const_vcalls());
3587 }
3588 
3589 static void writeWholeProgramDevirtResolutionByArg(
3590     SmallVector<uint64_t, 64> &NameVals, const std::vector<uint64_t> &args,
3591     const WholeProgramDevirtResolution::ByArg &ByArg) {
3592   NameVals.push_back(args.size());
3593   NameVals.insert(NameVals.end(), args.begin(), args.end());
3594 
3595   NameVals.push_back(ByArg.TheKind);
3596   NameVals.push_back(ByArg.Info);
3597   NameVals.push_back(ByArg.Byte);
3598   NameVals.push_back(ByArg.Bit);
3599 }
3600 
3601 static void writeWholeProgramDevirtResolution(
3602     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3603     uint64_t Id, const WholeProgramDevirtResolution &Wpd) {
3604   NameVals.push_back(Id);
3605 
3606   NameVals.push_back(Wpd.TheKind);
3607   NameVals.push_back(StrtabBuilder.add(Wpd.SingleImplName));
3608   NameVals.push_back(Wpd.SingleImplName.size());
3609 
3610   NameVals.push_back(Wpd.ResByArg.size());
3611   for (auto &A : Wpd.ResByArg)
3612     writeWholeProgramDevirtResolutionByArg(NameVals, A.first, A.second);
3613 }
3614 
3615 static void writeTypeIdSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
3616                                      StringTableBuilder &StrtabBuilder,
3617                                      const std::string &Id,
3618                                      const TypeIdSummary &Summary) {
3619   NameVals.push_back(StrtabBuilder.add(Id));
3620   NameVals.push_back(Id.size());
3621 
3622   NameVals.push_back(Summary.TTRes.TheKind);
3623   NameVals.push_back(Summary.TTRes.SizeM1BitWidth);
3624   NameVals.push_back(Summary.TTRes.AlignLog2);
3625   NameVals.push_back(Summary.TTRes.SizeM1);
3626   NameVals.push_back(Summary.TTRes.BitMask);
3627   NameVals.push_back(Summary.TTRes.InlineBits);
3628 
3629   for (auto &W : Summary.WPDRes)
3630     writeWholeProgramDevirtResolution(NameVals, StrtabBuilder, W.first,
3631                                       W.second);
3632 }
3633 
3634 static void writeTypeIdCompatibleVtableSummaryRecord(
3635     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3636     const std::string &Id, const TypeIdCompatibleVtableInfo &Summary,
3637     ValueEnumerator &VE) {
3638   NameVals.push_back(StrtabBuilder.add(Id));
3639   NameVals.push_back(Id.size());
3640 
3641   for (auto &P : Summary) {
3642     NameVals.push_back(P.AddressPointOffset);
3643     NameVals.push_back(VE.getValueID(P.VTableVI.getValue()));
3644   }
3645 }
3646 
3647 // Helper to emit a single function summary record.
3648 void ModuleBitcodeWriterBase::writePerModuleFunctionSummaryRecord(
3649     SmallVector<uint64_t, 64> &NameVals, GlobalValueSummary *Summary,
3650     unsigned ValueID, unsigned FSCallsAbbrev, unsigned FSCallsProfileAbbrev,
3651     const Function &F) {
3652   NameVals.push_back(ValueID);
3653 
3654   FunctionSummary *FS = cast<FunctionSummary>(Summary);
3655   writeFunctionTypeMetadataRecords(Stream, FS);
3656 
3657   auto SpecialRefCnts = FS->specialRefCounts();
3658   NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
3659   NameVals.push_back(FS->instCount());
3660   NameVals.push_back(getEncodedFFlags(FS->fflags()));
3661   NameVals.push_back(FS->refs().size());
3662   NameVals.push_back(SpecialRefCnts.first);  // rorefcnt
3663   NameVals.push_back(SpecialRefCnts.second); // worefcnt
3664 
3665   for (auto &RI : FS->refs())
3666     NameVals.push_back(VE.getValueID(RI.getValue()));
3667 
3668   bool HasProfileData =
3669       F.hasProfileData() || ForceSummaryEdgesCold != FunctionSummary::FSHT_None;
3670   for (auto &ECI : FS->calls()) {
3671     NameVals.push_back(getValueId(ECI.first));
3672     if (HasProfileData)
3673       NameVals.push_back(static_cast<uint8_t>(ECI.second.Hotness));
3674     else if (WriteRelBFToSummary)
3675       NameVals.push_back(ECI.second.RelBlockFreq);
3676   }
3677 
3678   unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
3679   unsigned Code =
3680       (HasProfileData ? bitc::FS_PERMODULE_PROFILE
3681                       : (WriteRelBFToSummary ? bitc::FS_PERMODULE_RELBF
3682                                              : bitc::FS_PERMODULE));
3683 
3684   // Emit the finished record.
3685   Stream.EmitRecord(Code, NameVals, FSAbbrev);
3686   NameVals.clear();
3687 }
3688 
3689 // Collect the global value references in the given variable's initializer,
3690 // and emit them in a summary record.
3691 void ModuleBitcodeWriterBase::writeModuleLevelReferences(
3692     const GlobalVariable &V, SmallVector<uint64_t, 64> &NameVals,
3693     unsigned FSModRefsAbbrev, unsigned FSModVTableRefsAbbrev) {
3694   auto VI = Index->getValueInfo(V.getGUID());
3695   if (!VI || VI.getSummaryList().empty()) {
3696     // Only declarations should not have a summary (a declaration might however
3697     // have a summary if the def was in module level asm).
3698     assert(V.isDeclaration());
3699     return;
3700   }
3701   auto *Summary = VI.getSummaryList()[0].get();
3702   NameVals.push_back(VE.getValueID(&V));
3703   GlobalVarSummary *VS = cast<GlobalVarSummary>(Summary);
3704   NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
3705   NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
3706 
3707   auto VTableFuncs = VS->vTableFuncs();
3708   if (!VTableFuncs.empty())
3709     NameVals.push_back(VS->refs().size());
3710 
3711   unsigned SizeBeforeRefs = NameVals.size();
3712   for (auto &RI : VS->refs())
3713     NameVals.push_back(VE.getValueID(RI.getValue()));
3714   // Sort the refs for determinism output, the vector returned by FS->refs() has
3715   // been initialized from a DenseSet.
3716   llvm::sort(NameVals.begin() + SizeBeforeRefs, NameVals.end());
3717 
3718   if (VTableFuncs.empty())
3719     Stream.EmitRecord(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS, NameVals,
3720                       FSModRefsAbbrev);
3721   else {
3722     // VTableFuncs pairs should already be sorted by offset.
3723     for (auto &P : VTableFuncs) {
3724       NameVals.push_back(VE.getValueID(P.FuncVI.getValue()));
3725       NameVals.push_back(P.VTableOffset);
3726     }
3727 
3728     Stream.EmitRecord(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS, NameVals,
3729                       FSModVTableRefsAbbrev);
3730   }
3731   NameVals.clear();
3732 }
3733 
3734 /// Emit the per-module summary section alongside the rest of
3735 /// the module's bitcode.
3736 void ModuleBitcodeWriterBase::writePerModuleGlobalValueSummary() {
3737   // By default we compile with ThinLTO if the module has a summary, but the
3738   // client can request full LTO with a module flag.
3739   bool IsThinLTO = true;
3740   if (auto *MD =
3741           mdconst::extract_or_null<ConstantInt>(M.getModuleFlag("ThinLTO")))
3742     IsThinLTO = MD->getZExtValue();
3743   Stream.EnterSubblock(IsThinLTO ? bitc::GLOBALVAL_SUMMARY_BLOCK_ID
3744                                  : bitc::FULL_LTO_GLOBALVAL_SUMMARY_BLOCK_ID,
3745                        4);
3746 
3747   Stream.EmitRecord(
3748       bitc::FS_VERSION,
3749       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
3750 
3751   // Write the index flags.
3752   uint64_t Flags = 0;
3753   // Bits 1-3 are set only in the combined index, skip them.
3754   if (Index->enableSplitLTOUnit())
3755     Flags |= 0x8;
3756   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Flags});
3757 
3758   if (Index->begin() == Index->end()) {
3759     Stream.ExitBlock();
3760     return;
3761   }
3762 
3763   for (const auto &GVI : valueIds()) {
3764     Stream.EmitRecord(bitc::FS_VALUE_GUID,
3765                       ArrayRef<uint64_t>{GVI.second, GVI.first});
3766   }
3767 
3768   // Abbrev for FS_PERMODULE_PROFILE.
3769   auto Abbv = std::make_shared<BitCodeAbbrev>();
3770   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_PROFILE));
3771   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3772   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3773   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3774   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3775   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3776   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
3777   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
3778   // numrefs x valueid, n x (valueid, hotness)
3779   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3780   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3781   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3782 
3783   // Abbrev for FS_PERMODULE or FS_PERMODULE_RELBF.
3784   Abbv = std::make_shared<BitCodeAbbrev>();
3785   if (WriteRelBFToSummary)
3786     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_RELBF));
3787   else
3788     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE));
3789   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3790   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3791   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3792   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3793   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3794   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
3795   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
3796   // numrefs x valueid, n x (valueid [, rel_block_freq])
3797   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3798   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3799   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3800 
3801   // Abbrev for FS_PERMODULE_GLOBALVAR_INIT_REFS.
3802   Abbv = std::make_shared<BitCodeAbbrev>();
3803   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS));
3804   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
3805   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
3806   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));  // valueids
3807   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3808   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3809 
3810   // Abbrev for FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS.
3811   Abbv = std::make_shared<BitCodeAbbrev>();
3812   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS));
3813   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
3814   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
3815   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numrefs
3816   // numrefs x valueid, n x (valueid , offset)
3817   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3818   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3819   unsigned FSModVTableRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3820 
3821   // Abbrev for FS_ALIAS.
3822   Abbv = std::make_shared<BitCodeAbbrev>();
3823   Abbv->Add(BitCodeAbbrevOp(bitc::FS_ALIAS));
3824   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3825   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3826   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3827   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3828 
3829   // Abbrev for FS_TYPE_ID_METADATA
3830   Abbv = std::make_shared<BitCodeAbbrev>();
3831   Abbv->Add(BitCodeAbbrevOp(bitc::FS_TYPE_ID_METADATA));
3832   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid strtab index
3833   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid length
3834   // n x (valueid , offset)
3835   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3836   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3837   unsigned TypeIdCompatibleVtableAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3838 
3839   SmallVector<uint64_t, 64> NameVals;
3840   // Iterate over the list of functions instead of the Index to
3841   // ensure the ordering is stable.
3842   for (const Function &F : M) {
3843     // Summary emission does not support anonymous functions, they have to
3844     // renamed using the anonymous function renaming pass.
3845     if (!F.hasName())
3846       report_fatal_error("Unexpected anonymous function when writing summary");
3847 
3848     ValueInfo VI = Index->getValueInfo(F.getGUID());
3849     if (!VI || VI.getSummaryList().empty()) {
3850       // Only declarations should not have a summary (a declaration might
3851       // however have a summary if the def was in module level asm).
3852       assert(F.isDeclaration());
3853       continue;
3854     }
3855     auto *Summary = VI.getSummaryList()[0].get();
3856     writePerModuleFunctionSummaryRecord(NameVals, Summary, VE.getValueID(&F),
3857                                         FSCallsAbbrev, FSCallsProfileAbbrev, F);
3858   }
3859 
3860   // Capture references from GlobalVariable initializers, which are outside
3861   // of a function scope.
3862   for (const GlobalVariable &G : M.globals())
3863     writeModuleLevelReferences(G, NameVals, FSModRefsAbbrev,
3864                                FSModVTableRefsAbbrev);
3865 
3866   for (const GlobalAlias &A : M.aliases()) {
3867     auto *Aliasee = A.getBaseObject();
3868     if (!Aliasee->hasName())
3869       // Nameless function don't have an entry in the summary, skip it.
3870       continue;
3871     auto AliasId = VE.getValueID(&A);
3872     auto AliaseeId = VE.getValueID(Aliasee);
3873     NameVals.push_back(AliasId);
3874     auto *Summary = Index->getGlobalValueSummary(A);
3875     AliasSummary *AS = cast<AliasSummary>(Summary);
3876     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
3877     NameVals.push_back(AliaseeId);
3878     Stream.EmitRecord(bitc::FS_ALIAS, NameVals, FSAliasAbbrev);
3879     NameVals.clear();
3880   }
3881 
3882   for (auto &S : Index->typeIdCompatibleVtableMap()) {
3883     writeTypeIdCompatibleVtableSummaryRecord(NameVals, StrtabBuilder, S.first,
3884                                              S.second, VE);
3885     Stream.EmitRecord(bitc::FS_TYPE_ID_METADATA, NameVals,
3886                       TypeIdCompatibleVtableAbbrev);
3887     NameVals.clear();
3888   }
3889 
3890   Stream.ExitBlock();
3891 }
3892 
3893 /// Emit the combined summary section into the combined index file.
3894 void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
3895   Stream.EnterSubblock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID, 3);
3896   Stream.EmitRecord(
3897       bitc::FS_VERSION,
3898       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
3899 
3900   // Write the index flags.
3901   uint64_t Flags = 0;
3902   if (Index.withGlobalValueDeadStripping())
3903     Flags |= 0x1;
3904   if (Index.skipModuleByDistributedBackend())
3905     Flags |= 0x2;
3906   if (Index.hasSyntheticEntryCounts())
3907     Flags |= 0x4;
3908   if (Index.enableSplitLTOUnit())
3909     Flags |= 0x8;
3910   if (Index.partiallySplitLTOUnits())
3911     Flags |= 0x10;
3912   if (Index.withAttributePropagation())
3913     Flags |= 0x20;
3914   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Flags});
3915 
3916   for (const auto &GVI : valueIds()) {
3917     Stream.EmitRecord(bitc::FS_VALUE_GUID,
3918                       ArrayRef<uint64_t>{GVI.second, GVI.first});
3919   }
3920 
3921   // Abbrev for FS_COMBINED.
3922   auto Abbv = std::make_shared<BitCodeAbbrev>();
3923   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED));
3924   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3925   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3926   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3927   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3928   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3929   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
3930   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3931   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
3932   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
3933   // numrefs x valueid, n x (valueid)
3934   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3935   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3936   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3937 
3938   // Abbrev for FS_COMBINED_PROFILE.
3939   Abbv = std::make_shared<BitCodeAbbrev>();
3940   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_PROFILE));
3941   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3942   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3943   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3944   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3945   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3946   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
3947   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3948   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
3949   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
3950   // numrefs x valueid, n x (valueid, hotness)
3951   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3952   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3953   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3954 
3955   // Abbrev for FS_COMBINED_GLOBALVAR_INIT_REFS.
3956   Abbv = std::make_shared<BitCodeAbbrev>();
3957   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS));
3958   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3959   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3960   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3961   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));    // valueids
3962   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3963   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3964 
3965   // Abbrev for FS_COMBINED_ALIAS.
3966   Abbv = std::make_shared<BitCodeAbbrev>();
3967   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_ALIAS));
3968   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3969   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3970   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3971   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3972   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3973 
3974   // The aliases are emitted as a post-pass, and will point to the value
3975   // id of the aliasee. Save them in a vector for post-processing.
3976   SmallVector<AliasSummary *, 64> Aliases;
3977 
3978   // Save the value id for each summary for alias emission.
3979   DenseMap<const GlobalValueSummary *, unsigned> SummaryToValueIdMap;
3980 
3981   SmallVector<uint64_t, 64> NameVals;
3982 
3983   // Set that will be populated during call to writeFunctionTypeMetadataRecords
3984   // with the type ids referenced by this index file.
3985   std::set<GlobalValue::GUID> ReferencedTypeIds;
3986 
3987   // For local linkage, we also emit the original name separately
3988   // immediately after the record.
3989   auto MaybeEmitOriginalName = [&](GlobalValueSummary &S) {
3990     if (!GlobalValue::isLocalLinkage(S.linkage()))
3991       return;
3992     NameVals.push_back(S.getOriginalName());
3993     Stream.EmitRecord(bitc::FS_COMBINED_ORIGINAL_NAME, NameVals);
3994     NameVals.clear();
3995   };
3996 
3997   std::set<GlobalValue::GUID> DefOrUseGUIDs;
3998   forEachSummary([&](GVInfo I, bool IsAliasee) {
3999     GlobalValueSummary *S = I.second;
4000     assert(S);
4001     DefOrUseGUIDs.insert(I.first);
4002     for (const ValueInfo &VI : S->refs())
4003       DefOrUseGUIDs.insert(VI.getGUID());
4004 
4005     auto ValueId = getValueId(I.first);
4006     assert(ValueId);
4007     SummaryToValueIdMap[S] = *ValueId;
4008 
4009     // If this is invoked for an aliasee, we want to record the above
4010     // mapping, but then not emit a summary entry (if the aliasee is
4011     // to be imported, we will invoke this separately with IsAliasee=false).
4012     if (IsAliasee)
4013       return;
4014 
4015     if (auto *AS = dyn_cast<AliasSummary>(S)) {
4016       // Will process aliases as a post-pass because the reader wants all
4017       // global to be loaded first.
4018       Aliases.push_back(AS);
4019       return;
4020     }
4021 
4022     if (auto *VS = dyn_cast<GlobalVarSummary>(S)) {
4023       NameVals.push_back(*ValueId);
4024       NameVals.push_back(Index.getModuleId(VS->modulePath()));
4025       NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
4026       NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
4027       for (auto &RI : VS->refs()) {
4028         auto RefValueId = getValueId(RI.getGUID());
4029         if (!RefValueId)
4030           continue;
4031         NameVals.push_back(*RefValueId);
4032       }
4033 
4034       // Emit the finished record.
4035       Stream.EmitRecord(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS, NameVals,
4036                         FSModRefsAbbrev);
4037       NameVals.clear();
4038       MaybeEmitOriginalName(*S);
4039       return;
4040     }
4041 
4042     auto *FS = cast<FunctionSummary>(S);
4043     writeFunctionTypeMetadataRecords(Stream, FS);
4044     getReferencedTypeIds(FS, ReferencedTypeIds);
4045 
4046     NameVals.push_back(*ValueId);
4047     NameVals.push_back(Index.getModuleId(FS->modulePath()));
4048     NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
4049     NameVals.push_back(FS->instCount());
4050     NameVals.push_back(getEncodedFFlags(FS->fflags()));
4051     NameVals.push_back(FS->entryCount());
4052 
4053     // Fill in below
4054     NameVals.push_back(0); // numrefs
4055     NameVals.push_back(0); // rorefcnt
4056     NameVals.push_back(0); // worefcnt
4057 
4058     unsigned Count = 0, RORefCnt = 0, WORefCnt = 0;
4059     for (auto &RI : FS->refs()) {
4060       auto RefValueId = getValueId(RI.getGUID());
4061       if (!RefValueId)
4062         continue;
4063       NameVals.push_back(*RefValueId);
4064       if (RI.isReadOnly())
4065         RORefCnt++;
4066       else if (RI.isWriteOnly())
4067         WORefCnt++;
4068       Count++;
4069     }
4070     NameVals[6] = Count;
4071     NameVals[7] = RORefCnt;
4072     NameVals[8] = WORefCnt;
4073 
4074     bool HasProfileData = false;
4075     for (auto &EI : FS->calls()) {
4076       HasProfileData |=
4077           EI.second.getHotness() != CalleeInfo::HotnessType::Unknown;
4078       if (HasProfileData)
4079         break;
4080     }
4081 
4082     for (auto &EI : FS->calls()) {
4083       // If this GUID doesn't have a value id, it doesn't have a function
4084       // summary and we don't need to record any calls to it.
4085       GlobalValue::GUID GUID = EI.first.getGUID();
4086       auto CallValueId = getValueId(GUID);
4087       if (!CallValueId) {
4088         // For SamplePGO, the indirect call targets for local functions will
4089         // have its original name annotated in profile. We try to find the
4090         // corresponding PGOFuncName as the GUID.
4091         GUID = Index.getGUIDFromOriginalID(GUID);
4092         if (GUID == 0)
4093           continue;
4094         CallValueId = getValueId(GUID);
4095         if (!CallValueId)
4096           continue;
4097         // The mapping from OriginalId to GUID may return a GUID
4098         // that corresponds to a static variable. Filter it out here.
4099         // This can happen when
4100         // 1) There is a call to a library function which does not have
4101         // a CallValidId;
4102         // 2) There is a static variable with the  OriginalGUID identical
4103         // to the GUID of the library function in 1);
4104         // When this happens, the logic for SamplePGO kicks in and
4105         // the static variable in 2) will be found, which needs to be
4106         // filtered out.
4107         auto *GVSum = Index.getGlobalValueSummary(GUID, false);
4108         if (GVSum &&
4109             GVSum->getSummaryKind() == GlobalValueSummary::GlobalVarKind)
4110           continue;
4111       }
4112       NameVals.push_back(*CallValueId);
4113       if (HasProfileData)
4114         NameVals.push_back(static_cast<uint8_t>(EI.second.Hotness));
4115     }
4116 
4117     unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
4118     unsigned Code =
4119         (HasProfileData ? bitc::FS_COMBINED_PROFILE : bitc::FS_COMBINED);
4120 
4121     // Emit the finished record.
4122     Stream.EmitRecord(Code, NameVals, FSAbbrev);
4123     NameVals.clear();
4124     MaybeEmitOriginalName(*S);
4125   });
4126 
4127   for (auto *AS : Aliases) {
4128     auto AliasValueId = SummaryToValueIdMap[AS];
4129     assert(AliasValueId);
4130     NameVals.push_back(AliasValueId);
4131     NameVals.push_back(Index.getModuleId(AS->modulePath()));
4132     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
4133     auto AliaseeValueId = SummaryToValueIdMap[&AS->getAliasee()];
4134     assert(AliaseeValueId);
4135     NameVals.push_back(AliaseeValueId);
4136 
4137     // Emit the finished record.
4138     Stream.EmitRecord(bitc::FS_COMBINED_ALIAS, NameVals, FSAliasAbbrev);
4139     NameVals.clear();
4140     MaybeEmitOriginalName(*AS);
4141 
4142     if (auto *FS = dyn_cast<FunctionSummary>(&AS->getAliasee()))
4143       getReferencedTypeIds(FS, ReferencedTypeIds);
4144   }
4145 
4146   if (!Index.cfiFunctionDefs().empty()) {
4147     for (auto &S : Index.cfiFunctionDefs()) {
4148       if (DefOrUseGUIDs.count(
4149               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4150         NameVals.push_back(StrtabBuilder.add(S));
4151         NameVals.push_back(S.size());
4152       }
4153     }
4154     if (!NameVals.empty()) {
4155       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DEFS, NameVals);
4156       NameVals.clear();
4157     }
4158   }
4159 
4160   if (!Index.cfiFunctionDecls().empty()) {
4161     for (auto &S : Index.cfiFunctionDecls()) {
4162       if (DefOrUseGUIDs.count(
4163               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4164         NameVals.push_back(StrtabBuilder.add(S));
4165         NameVals.push_back(S.size());
4166       }
4167     }
4168     if (!NameVals.empty()) {
4169       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DECLS, NameVals);
4170       NameVals.clear();
4171     }
4172   }
4173 
4174   // Walk the GUIDs that were referenced, and write the
4175   // corresponding type id records.
4176   for (auto &T : ReferencedTypeIds) {
4177     auto TidIter = Index.typeIds().equal_range(T);
4178     for (auto It = TidIter.first; It != TidIter.second; ++It) {
4179       writeTypeIdSummaryRecord(NameVals, StrtabBuilder, It->second.first,
4180                                It->second.second);
4181       Stream.EmitRecord(bitc::FS_TYPE_ID, NameVals);
4182       NameVals.clear();
4183     }
4184   }
4185 
4186   Stream.ExitBlock();
4187 }
4188 
4189 /// Create the "IDENTIFICATION_BLOCK_ID" containing a single string with the
4190 /// current llvm version, and a record for the epoch number.
4191 static void writeIdentificationBlock(BitstreamWriter &Stream) {
4192   Stream.EnterSubblock(bitc::IDENTIFICATION_BLOCK_ID, 5);
4193 
4194   // Write the "user readable" string identifying the bitcode producer
4195   auto Abbv = std::make_shared<BitCodeAbbrev>();
4196   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_STRING));
4197   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4198   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
4199   auto StringAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4200   writeStringRecord(Stream, bitc::IDENTIFICATION_CODE_STRING,
4201                     "LLVM" LLVM_VERSION_STRING, StringAbbrev);
4202 
4203   // Write the epoch version
4204   Abbv = std::make_shared<BitCodeAbbrev>();
4205   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_EPOCH));
4206   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
4207   auto EpochAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4208   constexpr std::array<unsigned, 1> Vals = {bitc::BITCODE_CURRENT_EPOCH};
4209   Stream.EmitRecord(bitc::IDENTIFICATION_CODE_EPOCH, Vals, EpochAbbrev);
4210   Stream.ExitBlock();
4211 }
4212 
4213 void ModuleBitcodeWriter::writeModuleHash(size_t BlockStartPos) {
4214   // Emit the module's hash.
4215   // MODULE_CODE_HASH: [5*i32]
4216   if (GenerateHash) {
4217     uint32_t Vals[5];
4218     Hasher.update(ArrayRef<uint8_t>((const uint8_t *)&(Buffer)[BlockStartPos],
4219                                     Buffer.size() - BlockStartPos));
4220     StringRef Hash = Hasher.result();
4221     for (int Pos = 0; Pos < 20; Pos += 4) {
4222       Vals[Pos / 4] = support::endian::read32be(Hash.data() + Pos);
4223     }
4224 
4225     // Emit the finished record.
4226     Stream.EmitRecord(bitc::MODULE_CODE_HASH, Vals);
4227 
4228     if (ModHash)
4229       // Save the written hash value.
4230       llvm::copy(Vals, std::begin(*ModHash));
4231   }
4232 }
4233 
4234 void ModuleBitcodeWriter::write() {
4235   writeIdentificationBlock(Stream);
4236 
4237   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4238   size_t BlockStartPos = Buffer.size();
4239 
4240   writeModuleVersion();
4241 
4242   // Emit blockinfo, which defines the standard abbreviations etc.
4243   writeBlockInfo();
4244 
4245   // Emit information describing all of the types in the module.
4246   writeTypeTable();
4247 
4248   // Emit information about attribute groups.
4249   writeAttributeGroupTable();
4250 
4251   // Emit information about parameter attributes.
4252   writeAttributeTable();
4253 
4254   writeComdats();
4255 
4256   // Emit top-level description of module, including target triple, inline asm,
4257   // descriptors for global variables, and function prototype info.
4258   writeModuleInfo();
4259 
4260   // Emit constants.
4261   writeModuleConstants();
4262 
4263   // Emit metadata kind names.
4264   writeModuleMetadataKinds();
4265 
4266   // Emit metadata.
4267   writeModuleMetadata();
4268 
4269   // Emit module-level use-lists.
4270   if (VE.shouldPreserveUseListOrder())
4271     writeUseListBlock(nullptr);
4272 
4273   writeOperandBundleTags();
4274   writeSyncScopeNames();
4275 
4276   // Emit function bodies.
4277   DenseMap<const Function *, uint64_t> FunctionToBitcodeIndex;
4278   for (Module::const_iterator F = M.begin(), E = M.end(); F != E; ++F)
4279     if (!F->isDeclaration())
4280       writeFunction(*F, FunctionToBitcodeIndex);
4281 
4282   // Need to write after the above call to WriteFunction which populates
4283   // the summary information in the index.
4284   if (Index)
4285     writePerModuleGlobalValueSummary();
4286 
4287   writeGlobalValueSymbolTable(FunctionToBitcodeIndex);
4288 
4289   writeModuleHash(BlockStartPos);
4290 
4291   Stream.ExitBlock();
4292 }
4293 
4294 static void writeInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
4295                                uint32_t &Position) {
4296   support::endian::write32le(&Buffer[Position], Value);
4297   Position += 4;
4298 }
4299 
4300 /// If generating a bc file on darwin, we have to emit a
4301 /// header and trailer to make it compatible with the system archiver.  To do
4302 /// this we emit the following header, and then emit a trailer that pads the
4303 /// file out to be a multiple of 16 bytes.
4304 ///
4305 /// struct bc_header {
4306 ///   uint32_t Magic;         // 0x0B17C0DE
4307 ///   uint32_t Version;       // Version, currently always 0.
4308 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
4309 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
4310 ///   uint32_t CPUType;       // CPU specifier.
4311 ///   ... potentially more later ...
4312 /// };
4313 static void emitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
4314                                          const Triple &TT) {
4315   unsigned CPUType = ~0U;
4316 
4317   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
4318   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
4319   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
4320   // specific constants here because they are implicitly part of the Darwin ABI.
4321   enum {
4322     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
4323     DARWIN_CPU_TYPE_X86        = 7,
4324     DARWIN_CPU_TYPE_ARM        = 12,
4325     DARWIN_CPU_TYPE_POWERPC    = 18
4326   };
4327 
4328   Triple::ArchType Arch = TT.getArch();
4329   if (Arch == Triple::x86_64)
4330     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
4331   else if (Arch == Triple::x86)
4332     CPUType = DARWIN_CPU_TYPE_X86;
4333   else if (Arch == Triple::ppc)
4334     CPUType = DARWIN_CPU_TYPE_POWERPC;
4335   else if (Arch == Triple::ppc64)
4336     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
4337   else if (Arch == Triple::arm || Arch == Triple::thumb)
4338     CPUType = DARWIN_CPU_TYPE_ARM;
4339 
4340   // Traditional Bitcode starts after header.
4341   assert(Buffer.size() >= BWH_HeaderSize &&
4342          "Expected header size to be reserved");
4343   unsigned BCOffset = BWH_HeaderSize;
4344   unsigned BCSize = Buffer.size() - BWH_HeaderSize;
4345 
4346   // Write the magic and version.
4347   unsigned Position = 0;
4348   writeInt32ToBuffer(0x0B17C0DE, Buffer, Position);
4349   writeInt32ToBuffer(0, Buffer, Position); // Version.
4350   writeInt32ToBuffer(BCOffset, Buffer, Position);
4351   writeInt32ToBuffer(BCSize, Buffer, Position);
4352   writeInt32ToBuffer(CPUType, Buffer, Position);
4353 
4354   // If the file is not a multiple of 16 bytes, insert dummy padding.
4355   while (Buffer.size() & 15)
4356     Buffer.push_back(0);
4357 }
4358 
4359 /// Helper to write the header common to all bitcode files.
4360 static void writeBitcodeHeader(BitstreamWriter &Stream) {
4361   // Emit the file header.
4362   Stream.Emit((unsigned)'B', 8);
4363   Stream.Emit((unsigned)'C', 8);
4364   Stream.Emit(0x0, 4);
4365   Stream.Emit(0xC, 4);
4366   Stream.Emit(0xE, 4);
4367   Stream.Emit(0xD, 4);
4368 }
4369 
4370 BitcodeWriter::BitcodeWriter(SmallVectorImpl<char> &Buffer)
4371     : Buffer(Buffer), Stream(new BitstreamWriter(Buffer)) {
4372   writeBitcodeHeader(*Stream);
4373 }
4374 
4375 BitcodeWriter::~BitcodeWriter() { assert(WroteStrtab); }
4376 
4377 void BitcodeWriter::writeBlob(unsigned Block, unsigned Record, StringRef Blob) {
4378   Stream->EnterSubblock(Block, 3);
4379 
4380   auto Abbv = std::make_shared<BitCodeAbbrev>();
4381   Abbv->Add(BitCodeAbbrevOp(Record));
4382   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
4383   auto AbbrevNo = Stream->EmitAbbrev(std::move(Abbv));
4384 
4385   Stream->EmitRecordWithBlob(AbbrevNo, ArrayRef<uint64_t>{Record}, Blob);
4386 
4387   Stream->ExitBlock();
4388 }
4389 
4390 void BitcodeWriter::writeSymtab() {
4391   assert(!WroteStrtab && !WroteSymtab);
4392 
4393   // If any module has module-level inline asm, we will require a registered asm
4394   // parser for the target so that we can create an accurate symbol table for
4395   // the module.
4396   for (Module *M : Mods) {
4397     if (M->getModuleInlineAsm().empty())
4398       continue;
4399 
4400     std::string Err;
4401     const Triple TT(M->getTargetTriple());
4402     const Target *T = TargetRegistry::lookupTarget(TT.str(), Err);
4403     if (!T || !T->hasMCAsmParser())
4404       return;
4405   }
4406 
4407   WroteSymtab = true;
4408   SmallVector<char, 0> Symtab;
4409   // The irsymtab::build function may be unable to create a symbol table if the
4410   // module is malformed (e.g. it contains an invalid alias). Writing a symbol
4411   // table is not required for correctness, but we still want to be able to
4412   // write malformed modules to bitcode files, so swallow the error.
4413   if (Error E = irsymtab::build(Mods, Symtab, StrtabBuilder, Alloc)) {
4414     consumeError(std::move(E));
4415     return;
4416   }
4417 
4418   writeBlob(bitc::SYMTAB_BLOCK_ID, bitc::SYMTAB_BLOB,
4419             {Symtab.data(), Symtab.size()});
4420 }
4421 
4422 void BitcodeWriter::writeStrtab() {
4423   assert(!WroteStrtab);
4424 
4425   std::vector<char> Strtab;
4426   StrtabBuilder.finalizeInOrder();
4427   Strtab.resize(StrtabBuilder.getSize());
4428   StrtabBuilder.write((uint8_t *)Strtab.data());
4429 
4430   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB,
4431             {Strtab.data(), Strtab.size()});
4432 
4433   WroteStrtab = true;
4434 }
4435 
4436 void BitcodeWriter::copyStrtab(StringRef Strtab) {
4437   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB, Strtab);
4438   WroteStrtab = true;
4439 }
4440 
4441 void BitcodeWriter::writeModule(const Module &M,
4442                                 bool ShouldPreserveUseListOrder,
4443                                 const ModuleSummaryIndex *Index,
4444                                 bool GenerateHash, ModuleHash *ModHash) {
4445   assert(!WroteStrtab);
4446 
4447   // The Mods vector is used by irsymtab::build, which requires non-const
4448   // Modules in case it needs to materialize metadata. But the bitcode writer
4449   // requires that the module is materialized, so we can cast to non-const here,
4450   // after checking that it is in fact materialized.
4451   assert(M.isMaterialized());
4452   Mods.push_back(const_cast<Module *>(&M));
4453 
4454   ModuleBitcodeWriter ModuleWriter(M, Buffer, StrtabBuilder, *Stream,
4455                                    ShouldPreserveUseListOrder, Index,
4456                                    GenerateHash, ModHash);
4457   ModuleWriter.write();
4458 }
4459 
4460 void BitcodeWriter::writeIndex(
4461     const ModuleSummaryIndex *Index,
4462     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4463   IndexBitcodeWriter IndexWriter(*Stream, StrtabBuilder, *Index,
4464                                  ModuleToSummariesForIndex);
4465   IndexWriter.write();
4466 }
4467 
4468 /// Write the specified module to the specified output stream.
4469 void llvm::WriteBitcodeToFile(const Module &M, raw_ostream &Out,
4470                               bool ShouldPreserveUseListOrder,
4471                               const ModuleSummaryIndex *Index,
4472                               bool GenerateHash, ModuleHash *ModHash) {
4473   SmallVector<char, 0> Buffer;
4474   Buffer.reserve(256*1024);
4475 
4476   // If this is darwin or another generic macho target, reserve space for the
4477   // header.
4478   Triple TT(M.getTargetTriple());
4479   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4480     Buffer.insert(Buffer.begin(), BWH_HeaderSize, 0);
4481 
4482   BitcodeWriter Writer(Buffer);
4483   Writer.writeModule(M, ShouldPreserveUseListOrder, Index, GenerateHash,
4484                      ModHash);
4485   Writer.writeSymtab();
4486   Writer.writeStrtab();
4487 
4488   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4489     emitDarwinBCHeaderAndTrailer(Buffer, TT);
4490 
4491   // Write the generated bitstream to "Out".
4492   Out.write((char*)&Buffer.front(), Buffer.size());
4493 }
4494 
4495 void IndexBitcodeWriter::write() {
4496   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4497 
4498   writeModuleVersion();
4499 
4500   // Write the module paths in the combined index.
4501   writeModStrings();
4502 
4503   // Write the summary combined index records.
4504   writeCombinedGlobalValueSummary();
4505 
4506   Stream.ExitBlock();
4507 }
4508 
4509 // Write the specified module summary index to the given raw output stream,
4510 // where it will be written in a new bitcode block. This is used when
4511 // writing the combined index file for ThinLTO. When writing a subset of the
4512 // index for a distributed backend, provide a \p ModuleToSummariesForIndex map.
4513 void llvm::WriteIndexToFile(
4514     const ModuleSummaryIndex &Index, raw_ostream &Out,
4515     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4516   SmallVector<char, 0> Buffer;
4517   Buffer.reserve(256 * 1024);
4518 
4519   BitcodeWriter Writer(Buffer);
4520   Writer.writeIndex(&Index, ModuleToSummariesForIndex);
4521   Writer.writeStrtab();
4522 
4523   Out.write((char *)&Buffer.front(), Buffer.size());
4524 }
4525 
4526 namespace {
4527 
4528 /// Class to manage the bitcode writing for a thin link bitcode file.
4529 class ThinLinkBitcodeWriter : public ModuleBitcodeWriterBase {
4530   /// ModHash is for use in ThinLTO incremental build, generated while writing
4531   /// the module bitcode file.
4532   const ModuleHash *ModHash;
4533 
4534 public:
4535   ThinLinkBitcodeWriter(const Module &M, StringTableBuilder &StrtabBuilder,
4536                         BitstreamWriter &Stream,
4537                         const ModuleSummaryIndex &Index,
4538                         const ModuleHash &ModHash)
4539       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
4540                                 /*ShouldPreserveUseListOrder=*/false, &Index),
4541         ModHash(&ModHash) {}
4542 
4543   void write();
4544 
4545 private:
4546   void writeSimplifiedModuleInfo();
4547 };
4548 
4549 } // end anonymous namespace
4550 
4551 // This function writes a simpilified module info for thin link bitcode file.
4552 // It only contains the source file name along with the name(the offset and
4553 // size in strtab) and linkage for global values. For the global value info
4554 // entry, in order to keep linkage at offset 5, there are three zeros used
4555 // as padding.
4556 void ThinLinkBitcodeWriter::writeSimplifiedModuleInfo() {
4557   SmallVector<unsigned, 64> Vals;
4558   // Emit the module's source file name.
4559   {
4560     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
4561     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
4562     if (Bits == SE_Char6)
4563       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
4564     else if (Bits == SE_Fixed7)
4565       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
4566 
4567     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
4568     auto Abbv = std::make_shared<BitCodeAbbrev>();
4569     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
4570     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4571     Abbv->Add(AbbrevOpToUse);
4572     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4573 
4574     for (const auto P : M.getSourceFileName())
4575       Vals.push_back((unsigned char)P);
4576 
4577     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
4578     Vals.clear();
4579   }
4580 
4581   // Emit the global variable information.
4582   for (const GlobalVariable &GV : M.globals()) {
4583     // GLOBALVAR: [strtab offset, strtab size, 0, 0, 0, linkage]
4584     Vals.push_back(StrtabBuilder.add(GV.getName()));
4585     Vals.push_back(GV.getName().size());
4586     Vals.push_back(0);
4587     Vals.push_back(0);
4588     Vals.push_back(0);
4589     Vals.push_back(getEncodedLinkage(GV));
4590 
4591     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals);
4592     Vals.clear();
4593   }
4594 
4595   // Emit the function proto information.
4596   for (const Function &F : M) {
4597     // FUNCTION:  [strtab offset, strtab size, 0, 0, 0, linkage]
4598     Vals.push_back(StrtabBuilder.add(F.getName()));
4599     Vals.push_back(F.getName().size());
4600     Vals.push_back(0);
4601     Vals.push_back(0);
4602     Vals.push_back(0);
4603     Vals.push_back(getEncodedLinkage(F));
4604 
4605     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals);
4606     Vals.clear();
4607   }
4608 
4609   // Emit the alias information.
4610   for (const GlobalAlias &A : M.aliases()) {
4611     // ALIAS: [strtab offset, strtab size, 0, 0, 0, linkage]
4612     Vals.push_back(StrtabBuilder.add(A.getName()));
4613     Vals.push_back(A.getName().size());
4614     Vals.push_back(0);
4615     Vals.push_back(0);
4616     Vals.push_back(0);
4617     Vals.push_back(getEncodedLinkage(A));
4618 
4619     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals);
4620     Vals.clear();
4621   }
4622 
4623   // Emit the ifunc information.
4624   for (const GlobalIFunc &I : M.ifuncs()) {
4625     // IFUNC: [strtab offset, strtab size, 0, 0, 0, linkage]
4626     Vals.push_back(StrtabBuilder.add(I.getName()));
4627     Vals.push_back(I.getName().size());
4628     Vals.push_back(0);
4629     Vals.push_back(0);
4630     Vals.push_back(0);
4631     Vals.push_back(getEncodedLinkage(I));
4632 
4633     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
4634     Vals.clear();
4635   }
4636 }
4637 
4638 void ThinLinkBitcodeWriter::write() {
4639   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4640 
4641   writeModuleVersion();
4642 
4643   writeSimplifiedModuleInfo();
4644 
4645   writePerModuleGlobalValueSummary();
4646 
4647   // Write module hash.
4648   Stream.EmitRecord(bitc::MODULE_CODE_HASH, ArrayRef<uint32_t>(*ModHash));
4649 
4650   Stream.ExitBlock();
4651 }
4652 
4653 void BitcodeWriter::writeThinLinkBitcode(const Module &M,
4654                                          const ModuleSummaryIndex &Index,
4655                                          const ModuleHash &ModHash) {
4656   assert(!WroteStrtab);
4657 
4658   // The Mods vector is used by irsymtab::build, which requires non-const
4659   // Modules in case it needs to materialize metadata. But the bitcode writer
4660   // requires that the module is materialized, so we can cast to non-const here,
4661   // after checking that it is in fact materialized.
4662   assert(M.isMaterialized());
4663   Mods.push_back(const_cast<Module *>(&M));
4664 
4665   ThinLinkBitcodeWriter ThinLinkWriter(M, StrtabBuilder, *Stream, Index,
4666                                        ModHash);
4667   ThinLinkWriter.write();
4668 }
4669 
4670 // Write the specified thin link bitcode file to the given raw output stream,
4671 // where it will be written in a new bitcode block. This is used when
4672 // writing the per-module index file for ThinLTO.
4673 void llvm::WriteThinLinkBitcodeToFile(const Module &M, raw_ostream &Out,
4674                                       const ModuleSummaryIndex &Index,
4675                                       const ModuleHash &ModHash) {
4676   SmallVector<char, 0> Buffer;
4677   Buffer.reserve(256 * 1024);
4678 
4679   BitcodeWriter Writer(Buffer);
4680   Writer.writeThinLinkBitcode(M, Index, ModHash);
4681   Writer.writeSymtab();
4682   Writer.writeStrtab();
4683 
4684   Out.write((char *)&Buffer.front(), Buffer.size());
4685 }
4686 
4687 static const char *getSectionNameForBitcode(const Triple &T) {
4688   switch (T.getObjectFormat()) {
4689   case Triple::MachO:
4690     return "__LLVM,__bitcode";
4691   case Triple::COFF:
4692   case Triple::ELF:
4693   case Triple::Wasm:
4694   case Triple::UnknownObjectFormat:
4695     return ".llvmbc";
4696   case Triple::XCOFF:
4697     llvm_unreachable("XCOFF is not yet implemented");
4698     break;
4699   }
4700   llvm_unreachable("Unimplemented ObjectFormatType");
4701 }
4702 
4703 static const char *getSectionNameForCommandline(const Triple &T) {
4704   switch (T.getObjectFormat()) {
4705   case Triple::MachO:
4706     return "__LLVM,__cmdline";
4707   case Triple::COFF:
4708   case Triple::ELF:
4709   case Triple::Wasm:
4710   case Triple::UnknownObjectFormat:
4711     return ".llvmcmd";
4712   case Triple::XCOFF:
4713     llvm_unreachable("XCOFF is not yet implemented");
4714     break;
4715   }
4716   llvm_unreachable("Unimplemented ObjectFormatType");
4717 }
4718 
4719 void llvm::EmbedBitcodeInModule(llvm::Module &M, llvm::MemoryBufferRef Buf,
4720                                 bool EmbedBitcode, bool EmbedMarker,
4721                                 const std::vector<uint8_t> *CmdArgs) {
4722   // Save llvm.compiler.used and remove it.
4723   SmallVector<Constant *, 2> UsedArray;
4724   SmallPtrSet<GlobalValue *, 4> UsedGlobals;
4725   Type *UsedElementType = Type::getInt8Ty(M.getContext())->getPointerTo(0);
4726   GlobalVariable *Used = collectUsedGlobalVariables(M, UsedGlobals, true);
4727   for (auto *GV : UsedGlobals) {
4728     if (GV->getName() != "llvm.embedded.module" &&
4729         GV->getName() != "llvm.cmdline")
4730       UsedArray.push_back(
4731           ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
4732   }
4733   if (Used)
4734     Used->eraseFromParent();
4735 
4736   // Embed the bitcode for the llvm module.
4737   std::string Data;
4738   ArrayRef<uint8_t> ModuleData;
4739   Triple T(M.getTargetTriple());
4740   // Create a constant that contains the bitcode.
4741   // In case of embedding a marker, ignore the input Buf and use the empty
4742   // ArrayRef. It is also legal to create a bitcode marker even Buf is empty.
4743   if (EmbedBitcode) {
4744     if (!isBitcode((const unsigned char *)Buf.getBufferStart(),
4745                    (const unsigned char *)Buf.getBufferEnd())) {
4746       // If the input is LLVM Assembly, bitcode is produced by serializing
4747       // the module. Use-lists order need to be preserved in this case.
4748       llvm::raw_string_ostream OS(Data);
4749       llvm::WriteBitcodeToFile(M, OS, /* ShouldPreserveUseListOrder */ true);
4750       ModuleData =
4751           ArrayRef<uint8_t>((const uint8_t *)OS.str().data(), OS.str().size());
4752     } else
4753       // If the input is LLVM bitcode, write the input byte stream directly.
4754       ModuleData = ArrayRef<uint8_t>((const uint8_t *)Buf.getBufferStart(),
4755                                      Buf.getBufferSize());
4756   }
4757   llvm::Constant *ModuleConstant =
4758       llvm::ConstantDataArray::get(M.getContext(), ModuleData);
4759   llvm::GlobalVariable *GV = new llvm::GlobalVariable(
4760       M, ModuleConstant->getType(), true, llvm::GlobalValue::PrivateLinkage,
4761       ModuleConstant);
4762   GV->setSection(getSectionNameForBitcode(T));
4763   UsedArray.push_back(
4764       ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
4765   if (llvm::GlobalVariable *Old =
4766           M.getGlobalVariable("llvm.embedded.module", true)) {
4767     assert(Old->hasOneUse() &&
4768            "llvm.embedded.module can only be used once in llvm.compiler.used");
4769     GV->takeName(Old);
4770     Old->eraseFromParent();
4771   } else {
4772     GV->setName("llvm.embedded.module");
4773   }
4774 
4775   // Skip if only bitcode needs to be embedded.
4776   if (EmbedMarker) {
4777     // Embed command-line options.
4778     ArrayRef<uint8_t> CmdData(const_cast<uint8_t *>(CmdArgs->data()),
4779                               CmdArgs->size());
4780     llvm::Constant *CmdConstant =
4781         llvm::ConstantDataArray::get(M.getContext(), CmdData);
4782     GV = new llvm::GlobalVariable(M, CmdConstant->getType(), true,
4783                                   llvm::GlobalValue::PrivateLinkage,
4784                                   CmdConstant);
4785     GV->setSection(getSectionNameForCommandline(T));
4786     UsedArray.push_back(
4787         ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
4788     if (llvm::GlobalVariable *Old = M.getGlobalVariable("llvm.cmdline", true)) {
4789       assert(Old->hasOneUse() &&
4790              "llvm.cmdline can only be used once in llvm.compiler.used");
4791       GV->takeName(Old);
4792       Old->eraseFromParent();
4793     } else {
4794       GV->setName("llvm.cmdline");
4795     }
4796   }
4797 
4798   if (UsedArray.empty())
4799     return;
4800 
4801   // Recreate llvm.compiler.used.
4802   ArrayType *ATy = ArrayType::get(UsedElementType, UsedArray.size());
4803   auto *NewUsed = new GlobalVariable(
4804       M, ATy, false, llvm::GlobalValue::AppendingLinkage,
4805       llvm::ConstantArray::get(ATy, UsedArray), "llvm.compiler.used");
4806   NewUsed->setSection("llvm.metadata");
4807 }
4808