xref: /llvm-project/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp (revision 8cd35ad854ab4458fd509447359066ea3578b494)
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/BitcodeCommon.h"
28 #include "llvm/Bitcode/BitcodeReader.h"
29 #include "llvm/Bitcode/LLVMBitCodes.h"
30 #include "llvm/Bitstream/BitCodes.h"
31 #include "llvm/Bitstream/BitstreamWriter.h"
32 #include "llvm/Config/llvm-config.h"
33 #include "llvm/IR/Attributes.h"
34 #include "llvm/IR/BasicBlock.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 static cl::opt<uint32_t> FlushThreshold(
90     "bitcode-flush-threshold", cl::Hidden, cl::init(512),
91     cl::desc("The threshold (unit M) for flushing LLVM bitcode."));
92 
93 static cl::opt<bool> WriteRelBFToSummary(
94     "write-relbf-to-summary", cl::Hidden, cl::init(false),
95     cl::desc("Write relative block frequency to function summary "));
96 
97 extern FunctionSummary::ForceSummaryHotnessType ForceSummaryEdgesCold;
98 
99 namespace {
100 
101 /// These are manifest constants used by the bitcode writer. They do not need to
102 /// be kept in sync with the reader, but need to be consistent within this file.
103 enum {
104   // VALUE_SYMTAB_BLOCK abbrev id's.
105   VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
106   VST_ENTRY_7_ABBREV,
107   VST_ENTRY_6_ABBREV,
108   VST_BBENTRY_6_ABBREV,
109 
110   // CONSTANTS_BLOCK abbrev id's.
111   CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
112   CONSTANTS_INTEGER_ABBREV,
113   CONSTANTS_CE_CAST_Abbrev,
114   CONSTANTS_NULL_Abbrev,
115 
116   // FUNCTION_BLOCK abbrev id's.
117   FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
118   FUNCTION_INST_UNOP_ABBREV,
119   FUNCTION_INST_UNOP_FLAGS_ABBREV,
120   FUNCTION_INST_BINOP_ABBREV,
121   FUNCTION_INST_BINOP_FLAGS_ABBREV,
122   FUNCTION_INST_CAST_ABBREV,
123   FUNCTION_INST_RET_VOID_ABBREV,
124   FUNCTION_INST_RET_VAL_ABBREV,
125   FUNCTION_INST_UNREACHABLE_ABBREV,
126   FUNCTION_INST_GEP_ABBREV,
127 };
128 
129 /// Abstract class to manage the bitcode writing, subclassed for each bitcode
130 /// file type.
131 class BitcodeWriterBase {
132 protected:
133   /// The stream created and owned by the client.
134   BitstreamWriter &Stream;
135 
136   StringTableBuilder &StrtabBuilder;
137 
138 public:
139   /// Constructs a BitcodeWriterBase object that writes to the provided
140   /// \p Stream.
141   BitcodeWriterBase(BitstreamWriter &Stream, StringTableBuilder &StrtabBuilder)
142       : Stream(Stream), StrtabBuilder(StrtabBuilder) {}
143 
144 protected:
145   void writeBitcodeHeader();
146   void writeModuleVersion();
147 };
148 
149 void BitcodeWriterBase::writeModuleVersion() {
150   // VERSION: [version#]
151   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, ArrayRef<uint64_t>{2});
152 }
153 
154 /// Base class to manage the module bitcode writing, currently subclassed for
155 /// ModuleBitcodeWriter and ThinLinkBitcodeWriter.
156 class ModuleBitcodeWriterBase : public BitcodeWriterBase {
157 protected:
158   /// The Module to write to bitcode.
159   const Module &M;
160 
161   /// Enumerates ids for all values in the module.
162   ValueEnumerator VE;
163 
164   /// Optional per-module index to write for ThinLTO.
165   const ModuleSummaryIndex *Index;
166 
167   /// Map that holds the correspondence between GUIDs in the summary index,
168   /// that came from indirect call profiles, and a value id generated by this
169   /// class to use in the VST and summary block records.
170   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
171 
172   /// Tracks the last value id recorded in the GUIDToValueMap.
173   unsigned GlobalValueId;
174 
175   /// Saves the offset of the VSTOffset record that must eventually be
176   /// backpatched with the offset of the actual VST.
177   uint64_t VSTOffsetPlaceholder = 0;
178 
179 public:
180   /// Constructs a ModuleBitcodeWriterBase object for the given Module,
181   /// writing to the provided \p Buffer.
182   ModuleBitcodeWriterBase(const Module &M, StringTableBuilder &StrtabBuilder,
183                           BitstreamWriter &Stream,
184                           bool ShouldPreserveUseListOrder,
185                           const ModuleSummaryIndex *Index)
186       : BitcodeWriterBase(Stream, StrtabBuilder), M(M),
187         VE(M, ShouldPreserveUseListOrder), Index(Index) {
188     // Assign ValueIds to any callee values in the index that came from
189     // indirect call profiles and were recorded as a GUID not a Value*
190     // (which would have been assigned an ID by the ValueEnumerator).
191     // The starting ValueId is just after the number of values in the
192     // ValueEnumerator, so that they can be emitted in the VST.
193     GlobalValueId = VE.getValues().size();
194     if (!Index)
195       return;
196     for (const auto &GUIDSummaryLists : *Index)
197       // Examine all summaries for this GUID.
198       for (auto &Summary : GUIDSummaryLists.second.SummaryList)
199         if (auto FS = dyn_cast<FunctionSummary>(Summary.get()))
200           // For each call in the function summary, see if the call
201           // is to a GUID (which means it is for an indirect call,
202           // otherwise we would have a Value for it). If so, synthesize
203           // a value id.
204           for (auto &CallEdge : FS->calls())
205             if (!CallEdge.first.haveGVs() || !CallEdge.first.getValue())
206               assignValueId(CallEdge.first.getGUID());
207   }
208 
209 protected:
210   void writePerModuleGlobalValueSummary();
211 
212 private:
213   void writePerModuleFunctionSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
214                                            GlobalValueSummary *Summary,
215                                            unsigned ValueID,
216                                            unsigned FSCallsAbbrev,
217                                            unsigned FSCallsProfileAbbrev,
218                                            const Function &F);
219   void writeModuleLevelReferences(const GlobalVariable &V,
220                                   SmallVector<uint64_t, 64> &NameVals,
221                                   unsigned FSModRefsAbbrev,
222                                   unsigned FSModVTableRefsAbbrev);
223 
224   void assignValueId(GlobalValue::GUID ValGUID) {
225     GUIDToValueIdMap[ValGUID] = ++GlobalValueId;
226   }
227 
228   unsigned getValueId(GlobalValue::GUID ValGUID) {
229     const auto &VMI = GUIDToValueIdMap.find(ValGUID);
230     // Expect that any GUID value had a value Id assigned by an
231     // earlier call to assignValueId.
232     assert(VMI != GUIDToValueIdMap.end() &&
233            "GUID does not have assigned value Id");
234     return VMI->second;
235   }
236 
237   // Helper to get the valueId for the type of value recorded in VI.
238   unsigned getValueId(ValueInfo VI) {
239     if (!VI.haveGVs() || !VI.getValue())
240       return getValueId(VI.getGUID());
241     return VE.getValueID(VI.getValue());
242   }
243 
244   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
245 };
246 
247 /// Class to manage the bitcode writing for a module.
248 class ModuleBitcodeWriter : public ModuleBitcodeWriterBase {
249   /// Pointer to the buffer allocated by caller for bitcode writing.
250   const SmallVectorImpl<char> &Buffer;
251 
252   /// True if a module hash record should be written.
253   bool GenerateHash;
254 
255   /// If non-null, when GenerateHash is true, the resulting hash is written
256   /// into ModHash.
257   ModuleHash *ModHash;
258 
259   SHA1 Hasher;
260 
261   /// The start bit of the identification block.
262   uint64_t BitcodeStartBit;
263 
264 public:
265   /// Constructs a ModuleBitcodeWriter object for the given Module,
266   /// writing to the provided \p Buffer.
267   ModuleBitcodeWriter(const Module &M, SmallVectorImpl<char> &Buffer,
268                       StringTableBuilder &StrtabBuilder,
269                       BitstreamWriter &Stream, bool ShouldPreserveUseListOrder,
270                       const ModuleSummaryIndex *Index, bool GenerateHash,
271                       ModuleHash *ModHash = nullptr)
272       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
273                                 ShouldPreserveUseListOrder, Index),
274         Buffer(Buffer), GenerateHash(GenerateHash), ModHash(ModHash),
275         BitcodeStartBit(Stream.GetCurrentBitNo()) {}
276 
277   /// Emit the current module to the bitstream.
278   void write();
279 
280 private:
281   uint64_t bitcodeStartBit() { return BitcodeStartBit; }
282 
283   size_t addToStrtab(StringRef Str);
284 
285   void writeAttributeGroupTable();
286   void writeAttributeTable();
287   void writeTypeTable();
288   void writeComdats();
289   void writeValueSymbolTableForwardDecl();
290   void writeModuleInfo();
291   void writeValueAsMetadata(const ValueAsMetadata *MD,
292                             SmallVectorImpl<uint64_t> &Record);
293   void writeMDTuple(const MDTuple *N, SmallVectorImpl<uint64_t> &Record,
294                     unsigned Abbrev);
295   unsigned createDILocationAbbrev();
296   void writeDILocation(const DILocation *N, SmallVectorImpl<uint64_t> &Record,
297                        unsigned &Abbrev);
298   unsigned createGenericDINodeAbbrev();
299   void writeGenericDINode(const GenericDINode *N,
300                           SmallVectorImpl<uint64_t> &Record, unsigned &Abbrev);
301   void writeDISubrange(const DISubrange *N, SmallVectorImpl<uint64_t> &Record,
302                        unsigned Abbrev);
303   void writeDIGenericSubrange(const DIGenericSubrange *N,
304                               SmallVectorImpl<uint64_t> &Record,
305                               unsigned Abbrev);
306   void writeDIEnumerator(const DIEnumerator *N,
307                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
308   void writeDIBasicType(const DIBasicType *N, SmallVectorImpl<uint64_t> &Record,
309                         unsigned Abbrev);
310   void writeDIStringType(const DIStringType *N,
311                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
312   void writeDIDerivedType(const DIDerivedType *N,
313                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
314   void writeDICompositeType(const DICompositeType *N,
315                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
316   void writeDISubroutineType(const DISubroutineType *N,
317                              SmallVectorImpl<uint64_t> &Record,
318                              unsigned Abbrev);
319   void writeDIFile(const DIFile *N, SmallVectorImpl<uint64_t> &Record,
320                    unsigned Abbrev);
321   void writeDICompileUnit(const DICompileUnit *N,
322                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
323   void writeDISubprogram(const DISubprogram *N,
324                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
325   void writeDILexicalBlock(const DILexicalBlock *N,
326                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
327   void writeDILexicalBlockFile(const DILexicalBlockFile *N,
328                                SmallVectorImpl<uint64_t> &Record,
329                                unsigned Abbrev);
330   void writeDICommonBlock(const DICommonBlock *N,
331                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
332   void writeDINamespace(const DINamespace *N, SmallVectorImpl<uint64_t> &Record,
333                         unsigned Abbrev);
334   void writeDIMacro(const DIMacro *N, SmallVectorImpl<uint64_t> &Record,
335                     unsigned Abbrev);
336   void writeDIMacroFile(const DIMacroFile *N, SmallVectorImpl<uint64_t> &Record,
337                         unsigned Abbrev);
338   void writeDIArgList(const DIArgList *N, SmallVectorImpl<uint64_t> &Record,
339                       unsigned Abbrev);
340   void writeDIModule(const DIModule *N, SmallVectorImpl<uint64_t> &Record,
341                      unsigned Abbrev);
342   void writeDITemplateTypeParameter(const DITemplateTypeParameter *N,
343                                     SmallVectorImpl<uint64_t> &Record,
344                                     unsigned Abbrev);
345   void writeDITemplateValueParameter(const DITemplateValueParameter *N,
346                                      SmallVectorImpl<uint64_t> &Record,
347                                      unsigned Abbrev);
348   void writeDIGlobalVariable(const DIGlobalVariable *N,
349                              SmallVectorImpl<uint64_t> &Record,
350                              unsigned Abbrev);
351   void writeDILocalVariable(const DILocalVariable *N,
352                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
353   void writeDILabel(const DILabel *N,
354                     SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
355   void writeDIExpression(const DIExpression *N,
356                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
357   void writeDIGlobalVariableExpression(const DIGlobalVariableExpression *N,
358                                        SmallVectorImpl<uint64_t> &Record,
359                                        unsigned Abbrev);
360   void writeDIObjCProperty(const DIObjCProperty *N,
361                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
362   void writeDIImportedEntity(const DIImportedEntity *N,
363                              SmallVectorImpl<uint64_t> &Record,
364                              unsigned Abbrev);
365   unsigned createNamedMetadataAbbrev();
366   void writeNamedMetadata(SmallVectorImpl<uint64_t> &Record);
367   unsigned createMetadataStringsAbbrev();
368   void writeMetadataStrings(ArrayRef<const Metadata *> Strings,
369                             SmallVectorImpl<uint64_t> &Record);
370   void writeMetadataRecords(ArrayRef<const Metadata *> MDs,
371                             SmallVectorImpl<uint64_t> &Record,
372                             std::vector<unsigned> *MDAbbrevs = nullptr,
373                             std::vector<uint64_t> *IndexPos = nullptr);
374   void writeModuleMetadata();
375   void writeFunctionMetadata(const Function &F);
376   void writeFunctionMetadataAttachment(const Function &F);
377   void writeGlobalVariableMetadataAttachment(const GlobalVariable &GV);
378   void pushGlobalMetadataAttachment(SmallVectorImpl<uint64_t> &Record,
379                                     const GlobalObject &GO);
380   void writeModuleMetadataKinds();
381   void writeOperandBundleTags();
382   void writeSyncScopeNames();
383   void writeConstants(unsigned FirstVal, unsigned LastVal, bool isGlobal);
384   void writeModuleConstants();
385   bool pushValueAndType(const Value *V, unsigned InstID,
386                         SmallVectorImpl<unsigned> &Vals);
387   void writeOperandBundles(const CallBase &CB, unsigned InstID);
388   void pushValue(const Value *V, unsigned InstID,
389                  SmallVectorImpl<unsigned> &Vals);
390   void pushValueSigned(const Value *V, unsigned InstID,
391                        SmallVectorImpl<uint64_t> &Vals);
392   void writeInstruction(const Instruction &I, unsigned InstID,
393                         SmallVectorImpl<unsigned> &Vals);
394   void writeFunctionLevelValueSymbolTable(const ValueSymbolTable &VST);
395   void writeGlobalValueSymbolTable(
396       DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
397   void writeUseList(UseListOrder &&Order);
398   void writeUseListBlock(const Function *F);
399   void
400   writeFunction(const Function &F,
401                 DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
402   void writeBlockInfo();
403   void writeModuleHash(size_t BlockStartPos);
404 
405   unsigned getEncodedSyncScopeID(SyncScope::ID SSID) {
406     return unsigned(SSID);
407   }
408 
409   unsigned getEncodedAlign(MaybeAlign Alignment) { return encode(Alignment); }
410 };
411 
412 /// Class to manage the bitcode writing for a combined index.
413 class IndexBitcodeWriter : public BitcodeWriterBase {
414   /// The combined index to write to bitcode.
415   const ModuleSummaryIndex &Index;
416 
417   /// When writing a subset of the index for distributed backends, client
418   /// provides a map of modules to the corresponding GUIDs/summaries to write.
419   const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex;
420 
421   /// Map that holds the correspondence between the GUID used in the combined
422   /// index and a value id generated by this class to use in references.
423   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
424 
425   /// Tracks the last value id recorded in the GUIDToValueMap.
426   unsigned GlobalValueId = 0;
427 
428 public:
429   /// Constructs a IndexBitcodeWriter object for the given combined index,
430   /// writing to the provided \p Buffer. When writing a subset of the index
431   /// for a distributed backend, provide a \p ModuleToSummariesForIndex map.
432   IndexBitcodeWriter(BitstreamWriter &Stream, StringTableBuilder &StrtabBuilder,
433                      const ModuleSummaryIndex &Index,
434                      const std::map<std::string, GVSummaryMapTy>
435                          *ModuleToSummariesForIndex = nullptr)
436       : BitcodeWriterBase(Stream, StrtabBuilder), Index(Index),
437         ModuleToSummariesForIndex(ModuleToSummariesForIndex) {
438     // Assign unique value ids to all summaries to be written, for use
439     // in writing out the call graph edges. Save the mapping from GUID
440     // to the new global value id to use when writing those edges, which
441     // are currently saved in the index in terms of GUID.
442     forEachSummary([&](GVInfo I, bool) {
443       GUIDToValueIdMap[I.first] = ++GlobalValueId;
444     });
445   }
446 
447   /// The below iterator returns the GUID and associated summary.
448   using GVInfo = std::pair<GlobalValue::GUID, GlobalValueSummary *>;
449 
450   /// Calls the callback for each value GUID and summary to be written to
451   /// bitcode. This hides the details of whether they are being pulled from the
452   /// entire index or just those in a provided ModuleToSummariesForIndex map.
453   template<typename Functor>
454   void forEachSummary(Functor Callback) {
455     if (ModuleToSummariesForIndex) {
456       for (auto &M : *ModuleToSummariesForIndex)
457         for (auto &Summary : M.second) {
458           Callback(Summary, false);
459           // Ensure aliasee is handled, e.g. for assigning a valueId,
460           // even if we are not importing the aliasee directly (the
461           // imported alias will contain a copy of aliasee).
462           if (auto *AS = dyn_cast<AliasSummary>(Summary.getSecond()))
463             Callback({AS->getAliaseeGUID(), &AS->getAliasee()}, true);
464         }
465     } else {
466       for (auto &Summaries : Index)
467         for (auto &Summary : Summaries.second.SummaryList)
468           Callback({Summaries.first, Summary.get()}, false);
469     }
470   }
471 
472   /// Calls the callback for each entry in the modulePaths StringMap that
473   /// should be written to the module path string table. This hides the details
474   /// of whether they are being pulled from the entire index or just those in a
475   /// provided ModuleToSummariesForIndex map.
476   template <typename Functor> void forEachModule(Functor Callback) {
477     if (ModuleToSummariesForIndex) {
478       for (const auto &M : *ModuleToSummariesForIndex) {
479         const auto &MPI = Index.modulePaths().find(M.first);
480         if (MPI == Index.modulePaths().end()) {
481           // This should only happen if the bitcode file was empty, in which
482           // case we shouldn't be importing (the ModuleToSummariesForIndex
483           // would only include the module we are writing and index for).
484           assert(ModuleToSummariesForIndex->size() == 1);
485           continue;
486         }
487         Callback(*MPI);
488       }
489     } else {
490       for (const auto &MPSE : Index.modulePaths())
491         Callback(MPSE);
492     }
493   }
494 
495   /// Main entry point for writing a combined index to bitcode.
496   void write();
497 
498 private:
499   void writeModStrings();
500   void writeCombinedGlobalValueSummary();
501 
502   Optional<unsigned> getValueId(GlobalValue::GUID ValGUID) {
503     auto VMI = GUIDToValueIdMap.find(ValGUID);
504     if (VMI == GUIDToValueIdMap.end())
505       return None;
506     return VMI->second;
507   }
508 
509   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
510 };
511 
512 } // end anonymous namespace
513 
514 static unsigned getEncodedCastOpcode(unsigned Opcode) {
515   switch (Opcode) {
516   default: llvm_unreachable("Unknown cast instruction!");
517   case Instruction::Trunc   : return bitc::CAST_TRUNC;
518   case Instruction::ZExt    : return bitc::CAST_ZEXT;
519   case Instruction::SExt    : return bitc::CAST_SEXT;
520   case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
521   case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
522   case Instruction::UIToFP  : return bitc::CAST_UITOFP;
523   case Instruction::SIToFP  : return bitc::CAST_SITOFP;
524   case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
525   case Instruction::FPExt   : return bitc::CAST_FPEXT;
526   case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
527   case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
528   case Instruction::BitCast : return bitc::CAST_BITCAST;
529   case Instruction::AddrSpaceCast: return bitc::CAST_ADDRSPACECAST;
530   }
531 }
532 
533 static unsigned getEncodedUnaryOpcode(unsigned Opcode) {
534   switch (Opcode) {
535   default: llvm_unreachable("Unknown binary instruction!");
536   case Instruction::FNeg: return bitc::UNOP_FNEG;
537   }
538 }
539 
540 static unsigned getEncodedBinaryOpcode(unsigned Opcode) {
541   switch (Opcode) {
542   default: llvm_unreachable("Unknown binary instruction!");
543   case Instruction::Add:
544   case Instruction::FAdd: return bitc::BINOP_ADD;
545   case Instruction::Sub:
546   case Instruction::FSub: return bitc::BINOP_SUB;
547   case Instruction::Mul:
548   case Instruction::FMul: return bitc::BINOP_MUL;
549   case Instruction::UDiv: return bitc::BINOP_UDIV;
550   case Instruction::FDiv:
551   case Instruction::SDiv: return bitc::BINOP_SDIV;
552   case Instruction::URem: return bitc::BINOP_UREM;
553   case Instruction::FRem:
554   case Instruction::SRem: return bitc::BINOP_SREM;
555   case Instruction::Shl:  return bitc::BINOP_SHL;
556   case Instruction::LShr: return bitc::BINOP_LSHR;
557   case Instruction::AShr: return bitc::BINOP_ASHR;
558   case Instruction::And:  return bitc::BINOP_AND;
559   case Instruction::Or:   return bitc::BINOP_OR;
560   case Instruction::Xor:  return bitc::BINOP_XOR;
561   }
562 }
563 
564 static unsigned getEncodedRMWOperation(AtomicRMWInst::BinOp Op) {
565   switch (Op) {
566   default: llvm_unreachable("Unknown RMW operation!");
567   case AtomicRMWInst::Xchg: return bitc::RMW_XCHG;
568   case AtomicRMWInst::Add: return bitc::RMW_ADD;
569   case AtomicRMWInst::Sub: return bitc::RMW_SUB;
570   case AtomicRMWInst::And: return bitc::RMW_AND;
571   case AtomicRMWInst::Nand: return bitc::RMW_NAND;
572   case AtomicRMWInst::Or: return bitc::RMW_OR;
573   case AtomicRMWInst::Xor: return bitc::RMW_XOR;
574   case AtomicRMWInst::Max: return bitc::RMW_MAX;
575   case AtomicRMWInst::Min: return bitc::RMW_MIN;
576   case AtomicRMWInst::UMax: return bitc::RMW_UMAX;
577   case AtomicRMWInst::UMin: return bitc::RMW_UMIN;
578   case AtomicRMWInst::FAdd: return bitc::RMW_FADD;
579   case AtomicRMWInst::FSub: return bitc::RMW_FSUB;
580   }
581 }
582 
583 static unsigned getEncodedOrdering(AtomicOrdering Ordering) {
584   switch (Ordering) {
585   case AtomicOrdering::NotAtomic: return bitc::ORDERING_NOTATOMIC;
586   case AtomicOrdering::Unordered: return bitc::ORDERING_UNORDERED;
587   case AtomicOrdering::Monotonic: return bitc::ORDERING_MONOTONIC;
588   case AtomicOrdering::Acquire: return bitc::ORDERING_ACQUIRE;
589   case AtomicOrdering::Release: return bitc::ORDERING_RELEASE;
590   case AtomicOrdering::AcquireRelease: return bitc::ORDERING_ACQREL;
591   case AtomicOrdering::SequentiallyConsistent: return bitc::ORDERING_SEQCST;
592   }
593   llvm_unreachable("Invalid ordering");
594 }
595 
596 static void writeStringRecord(BitstreamWriter &Stream, unsigned Code,
597                               StringRef Str, unsigned AbbrevToUse) {
598   SmallVector<unsigned, 64> Vals;
599 
600   // Code: [strchar x N]
601   for (unsigned i = 0, e = Str.size(); i != e; ++i) {
602     if (AbbrevToUse && !BitCodeAbbrevOp::isChar6(Str[i]))
603       AbbrevToUse = 0;
604     Vals.push_back(Str[i]);
605   }
606 
607   // Emit the finished record.
608   Stream.EmitRecord(Code, Vals, AbbrevToUse);
609 }
610 
611 static uint64_t getAttrKindEncoding(Attribute::AttrKind Kind) {
612   switch (Kind) {
613   case Attribute::Alignment:
614     return bitc::ATTR_KIND_ALIGNMENT;
615   case Attribute::AllocSize:
616     return bitc::ATTR_KIND_ALLOC_SIZE;
617   case Attribute::AlwaysInline:
618     return bitc::ATTR_KIND_ALWAYS_INLINE;
619   case Attribute::ArgMemOnly:
620     return bitc::ATTR_KIND_ARGMEMONLY;
621   case Attribute::Builtin:
622     return bitc::ATTR_KIND_BUILTIN;
623   case Attribute::ByVal:
624     return bitc::ATTR_KIND_BY_VAL;
625   case Attribute::Convergent:
626     return bitc::ATTR_KIND_CONVERGENT;
627   case Attribute::InAlloca:
628     return bitc::ATTR_KIND_IN_ALLOCA;
629   case Attribute::Cold:
630     return bitc::ATTR_KIND_COLD;
631   case Attribute::Hot:
632     return bitc::ATTR_KIND_HOT;
633   case Attribute::InaccessibleMemOnly:
634     return bitc::ATTR_KIND_INACCESSIBLEMEM_ONLY;
635   case Attribute::InaccessibleMemOrArgMemOnly:
636     return bitc::ATTR_KIND_INACCESSIBLEMEM_OR_ARGMEMONLY;
637   case Attribute::InlineHint:
638     return bitc::ATTR_KIND_INLINE_HINT;
639   case Attribute::InReg:
640     return bitc::ATTR_KIND_IN_REG;
641   case Attribute::JumpTable:
642     return bitc::ATTR_KIND_JUMP_TABLE;
643   case Attribute::MinSize:
644     return bitc::ATTR_KIND_MIN_SIZE;
645   case Attribute::Naked:
646     return bitc::ATTR_KIND_NAKED;
647   case Attribute::Nest:
648     return bitc::ATTR_KIND_NEST;
649   case Attribute::NoAlias:
650     return bitc::ATTR_KIND_NO_ALIAS;
651   case Attribute::NoBuiltin:
652     return bitc::ATTR_KIND_NO_BUILTIN;
653   case Attribute::NoCallback:
654     return bitc::ATTR_KIND_NO_CALLBACK;
655   case Attribute::NoCapture:
656     return bitc::ATTR_KIND_NO_CAPTURE;
657   case Attribute::NoDuplicate:
658     return bitc::ATTR_KIND_NO_DUPLICATE;
659   case Attribute::NoFree:
660     return bitc::ATTR_KIND_NOFREE;
661   case Attribute::NoImplicitFloat:
662     return bitc::ATTR_KIND_NO_IMPLICIT_FLOAT;
663   case Attribute::NoInline:
664     return bitc::ATTR_KIND_NO_INLINE;
665   case Attribute::NoRecurse:
666     return bitc::ATTR_KIND_NO_RECURSE;
667   case Attribute::NoMerge:
668     return bitc::ATTR_KIND_NO_MERGE;
669   case Attribute::NonLazyBind:
670     return bitc::ATTR_KIND_NON_LAZY_BIND;
671   case Attribute::NonNull:
672     return bitc::ATTR_KIND_NON_NULL;
673   case Attribute::Dereferenceable:
674     return bitc::ATTR_KIND_DEREFERENCEABLE;
675   case Attribute::DereferenceableOrNull:
676     return bitc::ATTR_KIND_DEREFERENCEABLE_OR_NULL;
677   case Attribute::NoRedZone:
678     return bitc::ATTR_KIND_NO_RED_ZONE;
679   case Attribute::NoReturn:
680     return bitc::ATTR_KIND_NO_RETURN;
681   case Attribute::NoSync:
682     return bitc::ATTR_KIND_NOSYNC;
683   case Attribute::NoCfCheck:
684     return bitc::ATTR_KIND_NOCF_CHECK;
685   case Attribute::NoProfile:
686     return bitc::ATTR_KIND_NO_PROFILE;
687   case Attribute::NoUnwind:
688     return bitc::ATTR_KIND_NO_UNWIND;
689   case Attribute::NoSanitizeCoverage:
690     return bitc::ATTR_KIND_NO_SANITIZE_COVERAGE;
691   case Attribute::NullPointerIsValid:
692     return bitc::ATTR_KIND_NULL_POINTER_IS_VALID;
693   case Attribute::OptForFuzzing:
694     return bitc::ATTR_KIND_OPT_FOR_FUZZING;
695   case Attribute::OptimizeForSize:
696     return bitc::ATTR_KIND_OPTIMIZE_FOR_SIZE;
697   case Attribute::OptimizeNone:
698     return bitc::ATTR_KIND_OPTIMIZE_NONE;
699   case Attribute::ReadNone:
700     return bitc::ATTR_KIND_READ_NONE;
701   case Attribute::ReadOnly:
702     return bitc::ATTR_KIND_READ_ONLY;
703   case Attribute::Returned:
704     return bitc::ATTR_KIND_RETURNED;
705   case Attribute::ReturnsTwice:
706     return bitc::ATTR_KIND_RETURNS_TWICE;
707   case Attribute::SExt:
708     return bitc::ATTR_KIND_S_EXT;
709   case Attribute::Speculatable:
710     return bitc::ATTR_KIND_SPECULATABLE;
711   case Attribute::StackAlignment:
712     return bitc::ATTR_KIND_STACK_ALIGNMENT;
713   case Attribute::StackProtect:
714     return bitc::ATTR_KIND_STACK_PROTECT;
715   case Attribute::StackProtectReq:
716     return bitc::ATTR_KIND_STACK_PROTECT_REQ;
717   case Attribute::StackProtectStrong:
718     return bitc::ATTR_KIND_STACK_PROTECT_STRONG;
719   case Attribute::SafeStack:
720     return bitc::ATTR_KIND_SAFESTACK;
721   case Attribute::ShadowCallStack:
722     return bitc::ATTR_KIND_SHADOWCALLSTACK;
723   case Attribute::StrictFP:
724     return bitc::ATTR_KIND_STRICT_FP;
725   case Attribute::StructRet:
726     return bitc::ATTR_KIND_STRUCT_RET;
727   case Attribute::SanitizeAddress:
728     return bitc::ATTR_KIND_SANITIZE_ADDRESS;
729   case Attribute::SanitizeHWAddress:
730     return bitc::ATTR_KIND_SANITIZE_HWADDRESS;
731   case Attribute::SanitizeThread:
732     return bitc::ATTR_KIND_SANITIZE_THREAD;
733   case Attribute::SanitizeMemory:
734     return bitc::ATTR_KIND_SANITIZE_MEMORY;
735   case Attribute::SpeculativeLoadHardening:
736     return bitc::ATTR_KIND_SPECULATIVE_LOAD_HARDENING;
737   case Attribute::SwiftError:
738     return bitc::ATTR_KIND_SWIFT_ERROR;
739   case Attribute::SwiftSelf:
740     return bitc::ATTR_KIND_SWIFT_SELF;
741   case Attribute::SwiftAsync:
742     return bitc::ATTR_KIND_SWIFT_ASYNC;
743   case Attribute::UWTable:
744     return bitc::ATTR_KIND_UW_TABLE;
745   case Attribute::VScaleRange:
746     return bitc::ATTR_KIND_VSCALE_RANGE;
747   case Attribute::WillReturn:
748     return bitc::ATTR_KIND_WILLRETURN;
749   case Attribute::WriteOnly:
750     return bitc::ATTR_KIND_WRITEONLY;
751   case Attribute::ZExt:
752     return bitc::ATTR_KIND_Z_EXT;
753   case Attribute::ImmArg:
754     return bitc::ATTR_KIND_IMMARG;
755   case Attribute::SanitizeMemTag:
756     return bitc::ATTR_KIND_SANITIZE_MEMTAG;
757   case Attribute::Preallocated:
758     return bitc::ATTR_KIND_PREALLOCATED;
759   case Attribute::NoUndef:
760     return bitc::ATTR_KIND_NOUNDEF;
761   case Attribute::ByRef:
762     return bitc::ATTR_KIND_BYREF;
763   case Attribute::MustProgress:
764     return bitc::ATTR_KIND_MUSTPROGRESS;
765   case Attribute::EndAttrKinds:
766     llvm_unreachable("Can not encode end-attribute kinds marker.");
767   case Attribute::None:
768     llvm_unreachable("Can not encode none-attribute.");
769   case Attribute::EmptyKey:
770   case Attribute::TombstoneKey:
771     llvm_unreachable("Trying to encode EmptyKey/TombstoneKey");
772   }
773 
774   llvm_unreachable("Trying to encode unknown attribute");
775 }
776 
777 void ModuleBitcodeWriter::writeAttributeGroupTable() {
778   const std::vector<ValueEnumerator::IndexAndAttrSet> &AttrGrps =
779       VE.getAttributeGroups();
780   if (AttrGrps.empty()) return;
781 
782   Stream.EnterSubblock(bitc::PARAMATTR_GROUP_BLOCK_ID, 3);
783 
784   SmallVector<uint64_t, 64> Record;
785   for (ValueEnumerator::IndexAndAttrSet Pair : AttrGrps) {
786     unsigned AttrListIndex = Pair.first;
787     AttributeSet AS = Pair.second;
788     Record.push_back(VE.getAttributeGroupID(Pair));
789     Record.push_back(AttrListIndex);
790 
791     for (Attribute Attr : AS) {
792       if (Attr.isEnumAttribute()) {
793         Record.push_back(0);
794         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
795       } else if (Attr.isIntAttribute()) {
796         Record.push_back(1);
797         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
798         Record.push_back(Attr.getValueAsInt());
799       } else if (Attr.isStringAttribute()) {
800         StringRef Kind = Attr.getKindAsString();
801         StringRef Val = Attr.getValueAsString();
802 
803         Record.push_back(Val.empty() ? 3 : 4);
804         Record.append(Kind.begin(), Kind.end());
805         Record.push_back(0);
806         if (!Val.empty()) {
807           Record.append(Val.begin(), Val.end());
808           Record.push_back(0);
809         }
810       } else {
811         assert(Attr.isTypeAttribute());
812         Type *Ty = Attr.getValueAsType();
813         Record.push_back(Ty ? 6 : 5);
814         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
815         if (Ty)
816           Record.push_back(VE.getTypeID(Attr.getValueAsType()));
817       }
818     }
819 
820     Stream.EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
821     Record.clear();
822   }
823 
824   Stream.ExitBlock();
825 }
826 
827 void ModuleBitcodeWriter::writeAttributeTable() {
828   const std::vector<AttributeList> &Attrs = VE.getAttributeLists();
829   if (Attrs.empty()) return;
830 
831   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
832 
833   SmallVector<uint64_t, 64> Record;
834   for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
835     AttributeList AL = Attrs[i];
836     for (unsigned i = AL.index_begin(), e = AL.index_end(); i != e; ++i) {
837       AttributeSet AS = AL.getAttributes(i);
838       if (AS.hasAttributes())
839         Record.push_back(VE.getAttributeGroupID({i, AS}));
840     }
841 
842     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
843     Record.clear();
844   }
845 
846   Stream.ExitBlock();
847 }
848 
849 /// WriteTypeTable - Write out the type table for a module.
850 void ModuleBitcodeWriter::writeTypeTable() {
851   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
852 
853   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
854   SmallVector<uint64_t, 64> TypeVals;
855 
856   uint64_t NumBits = VE.computeBitsRequiredForTypeIndicies();
857 
858   // Abbrev for TYPE_CODE_POINTER.
859   auto Abbv = std::make_shared<BitCodeAbbrev>();
860   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
861   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
862   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
863   unsigned PtrAbbrev = Stream.EmitAbbrev(std::move(Abbv));
864 
865   // Abbrev for TYPE_CODE_OPAQUE_POINTER.
866   Abbv = std::make_shared<BitCodeAbbrev>();
867   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_OPAQUE_POINTER));
868   Abbv->Add(BitCodeAbbrevOp(0)); // Addrspace = 0
869   unsigned OpaquePtrAbbrev = Stream.EmitAbbrev(std::move(Abbv));
870 
871   // Abbrev for TYPE_CODE_FUNCTION.
872   Abbv = std::make_shared<BitCodeAbbrev>();
873   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
874   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
875   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
876   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
877   unsigned FunctionAbbrev = Stream.EmitAbbrev(std::move(Abbv));
878 
879   // Abbrev for TYPE_CODE_STRUCT_ANON.
880   Abbv = std::make_shared<BitCodeAbbrev>();
881   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
882   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
883   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
884   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
885   unsigned StructAnonAbbrev = Stream.EmitAbbrev(std::move(Abbv));
886 
887   // Abbrev for TYPE_CODE_STRUCT_NAME.
888   Abbv = std::make_shared<BitCodeAbbrev>();
889   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
890   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
891   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
892   unsigned StructNameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
893 
894   // Abbrev for TYPE_CODE_STRUCT_NAMED.
895   Abbv = std::make_shared<BitCodeAbbrev>();
896   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
897   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
898   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
899   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
900   unsigned StructNamedAbbrev = Stream.EmitAbbrev(std::move(Abbv));
901 
902   // Abbrev for TYPE_CODE_ARRAY.
903   Abbv = std::make_shared<BitCodeAbbrev>();
904   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
905   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
906   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
907   unsigned ArrayAbbrev = Stream.EmitAbbrev(std::move(Abbv));
908 
909   // Emit an entry count so the reader can reserve space.
910   TypeVals.push_back(TypeList.size());
911   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
912   TypeVals.clear();
913 
914   // Loop over all of the types, emitting each in turn.
915   for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
916     Type *T = TypeList[i];
917     int AbbrevToUse = 0;
918     unsigned Code = 0;
919 
920     switch (T->getTypeID()) {
921     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;      break;
922     case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;      break;
923     case Type::BFloatTyID:    Code = bitc::TYPE_CODE_BFLOAT;    break;
924     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;     break;
925     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE;    break;
926     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80;  break;
927     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128;     break;
928     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
929     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;     break;
930     case Type::MetadataTyID:  Code = bitc::TYPE_CODE_METADATA;  break;
931     case Type::X86_MMXTyID:   Code = bitc::TYPE_CODE_X86_MMX;   break;
932     case Type::X86_AMXTyID:   Code = bitc::TYPE_CODE_X86_AMX;   break;
933     case Type::TokenTyID:     Code = bitc::TYPE_CODE_TOKEN;     break;
934     case Type::IntegerTyID:
935       // INTEGER: [width]
936       Code = bitc::TYPE_CODE_INTEGER;
937       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
938       break;
939     case Type::PointerTyID: {
940       PointerType *PTy = cast<PointerType>(T);
941       unsigned AddressSpace = PTy->getAddressSpace();
942       if (PTy->isOpaque()) {
943         // OPAQUE_POINTER: [address space]
944         Code = bitc::TYPE_CODE_OPAQUE_POINTER;
945         TypeVals.push_back(AddressSpace);
946         if (AddressSpace == 0)
947           AbbrevToUse = OpaquePtrAbbrev;
948       } else {
949         // POINTER: [pointee type, address space]
950         Code = bitc::TYPE_CODE_POINTER;
951         TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
952         TypeVals.push_back(AddressSpace);
953         if (AddressSpace == 0)
954           AbbrevToUse = PtrAbbrev;
955       }
956       break;
957     }
958     case Type::FunctionTyID: {
959       FunctionType *FT = cast<FunctionType>(T);
960       // FUNCTION: [isvararg, retty, paramty x N]
961       Code = bitc::TYPE_CODE_FUNCTION;
962       TypeVals.push_back(FT->isVarArg());
963       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
964       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
965         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
966       AbbrevToUse = FunctionAbbrev;
967       break;
968     }
969     case Type::StructTyID: {
970       StructType *ST = cast<StructType>(T);
971       // STRUCT: [ispacked, eltty x N]
972       TypeVals.push_back(ST->isPacked());
973       // Output all of the element types.
974       for (StructType::element_iterator I = ST->element_begin(),
975            E = ST->element_end(); I != E; ++I)
976         TypeVals.push_back(VE.getTypeID(*I));
977 
978       if (ST->isLiteral()) {
979         Code = bitc::TYPE_CODE_STRUCT_ANON;
980         AbbrevToUse = StructAnonAbbrev;
981       } else {
982         if (ST->isOpaque()) {
983           Code = bitc::TYPE_CODE_OPAQUE;
984         } else {
985           Code = bitc::TYPE_CODE_STRUCT_NAMED;
986           AbbrevToUse = StructNamedAbbrev;
987         }
988 
989         // Emit the name if it is present.
990         if (!ST->getName().empty())
991           writeStringRecord(Stream, bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
992                             StructNameAbbrev);
993       }
994       break;
995     }
996     case Type::ArrayTyID: {
997       ArrayType *AT = cast<ArrayType>(T);
998       // ARRAY: [numelts, eltty]
999       Code = bitc::TYPE_CODE_ARRAY;
1000       TypeVals.push_back(AT->getNumElements());
1001       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
1002       AbbrevToUse = ArrayAbbrev;
1003       break;
1004     }
1005     case Type::FixedVectorTyID:
1006     case Type::ScalableVectorTyID: {
1007       VectorType *VT = cast<VectorType>(T);
1008       // VECTOR [numelts, eltty] or
1009       //        [numelts, eltty, scalable]
1010       Code = bitc::TYPE_CODE_VECTOR;
1011       TypeVals.push_back(VT->getElementCount().getKnownMinValue());
1012       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
1013       if (isa<ScalableVectorType>(VT))
1014         TypeVals.push_back(true);
1015       break;
1016     }
1017     }
1018 
1019     // Emit the finished record.
1020     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
1021     TypeVals.clear();
1022   }
1023 
1024   Stream.ExitBlock();
1025 }
1026 
1027 static unsigned getEncodedLinkage(const GlobalValue::LinkageTypes Linkage) {
1028   switch (Linkage) {
1029   case GlobalValue::ExternalLinkage:
1030     return 0;
1031   case GlobalValue::WeakAnyLinkage:
1032     return 16;
1033   case GlobalValue::AppendingLinkage:
1034     return 2;
1035   case GlobalValue::InternalLinkage:
1036     return 3;
1037   case GlobalValue::LinkOnceAnyLinkage:
1038     return 18;
1039   case GlobalValue::ExternalWeakLinkage:
1040     return 7;
1041   case GlobalValue::CommonLinkage:
1042     return 8;
1043   case GlobalValue::PrivateLinkage:
1044     return 9;
1045   case GlobalValue::WeakODRLinkage:
1046     return 17;
1047   case GlobalValue::LinkOnceODRLinkage:
1048     return 19;
1049   case GlobalValue::AvailableExternallyLinkage:
1050     return 12;
1051   }
1052   llvm_unreachable("Invalid linkage");
1053 }
1054 
1055 static unsigned getEncodedLinkage(const GlobalValue &GV) {
1056   return getEncodedLinkage(GV.getLinkage());
1057 }
1058 
1059 static uint64_t getEncodedFFlags(FunctionSummary::FFlags Flags) {
1060   uint64_t RawFlags = 0;
1061   RawFlags |= Flags.ReadNone;
1062   RawFlags |= (Flags.ReadOnly << 1);
1063   RawFlags |= (Flags.NoRecurse << 2);
1064   RawFlags |= (Flags.ReturnDoesNotAlias << 3);
1065   RawFlags |= (Flags.NoInline << 4);
1066   RawFlags |= (Flags.AlwaysInline << 5);
1067   return RawFlags;
1068 }
1069 
1070 // Decode the flags for GlobalValue in the summary. See getDecodedGVSummaryFlags
1071 // in BitcodeReader.cpp.
1072 static uint64_t getEncodedGVSummaryFlags(GlobalValueSummary::GVFlags Flags) {
1073   uint64_t RawFlags = 0;
1074 
1075   RawFlags |= Flags.NotEligibleToImport; // bool
1076   RawFlags |= (Flags.Live << 1);
1077   RawFlags |= (Flags.DSOLocal << 2);
1078   RawFlags |= (Flags.CanAutoHide << 3);
1079 
1080   // Linkage don't need to be remapped at that time for the summary. Any future
1081   // change to the getEncodedLinkage() function will need to be taken into
1082   // account here as well.
1083   RawFlags = (RawFlags << 4) | Flags.Linkage; // 4 bits
1084 
1085   RawFlags |= (Flags.Visibility << 8); // 2 bits
1086 
1087   return RawFlags;
1088 }
1089 
1090 static uint64_t getEncodedGVarFlags(GlobalVarSummary::GVarFlags Flags) {
1091   uint64_t RawFlags = Flags.MaybeReadOnly | (Flags.MaybeWriteOnly << 1) |
1092                       (Flags.Constant << 2) | Flags.VCallVisibility << 3;
1093   return RawFlags;
1094 }
1095 
1096 static unsigned getEncodedVisibility(const GlobalValue &GV) {
1097   switch (GV.getVisibility()) {
1098   case GlobalValue::DefaultVisibility:   return 0;
1099   case GlobalValue::HiddenVisibility:    return 1;
1100   case GlobalValue::ProtectedVisibility: return 2;
1101   }
1102   llvm_unreachable("Invalid visibility");
1103 }
1104 
1105 static unsigned getEncodedDLLStorageClass(const GlobalValue &GV) {
1106   switch (GV.getDLLStorageClass()) {
1107   case GlobalValue::DefaultStorageClass:   return 0;
1108   case GlobalValue::DLLImportStorageClass: return 1;
1109   case GlobalValue::DLLExportStorageClass: return 2;
1110   }
1111   llvm_unreachable("Invalid DLL storage class");
1112 }
1113 
1114 static unsigned getEncodedThreadLocalMode(const GlobalValue &GV) {
1115   switch (GV.getThreadLocalMode()) {
1116     case GlobalVariable::NotThreadLocal:         return 0;
1117     case GlobalVariable::GeneralDynamicTLSModel: return 1;
1118     case GlobalVariable::LocalDynamicTLSModel:   return 2;
1119     case GlobalVariable::InitialExecTLSModel:    return 3;
1120     case GlobalVariable::LocalExecTLSModel:      return 4;
1121   }
1122   llvm_unreachable("Invalid TLS model");
1123 }
1124 
1125 static unsigned getEncodedComdatSelectionKind(const Comdat &C) {
1126   switch (C.getSelectionKind()) {
1127   case Comdat::Any:
1128     return bitc::COMDAT_SELECTION_KIND_ANY;
1129   case Comdat::ExactMatch:
1130     return bitc::COMDAT_SELECTION_KIND_EXACT_MATCH;
1131   case Comdat::Largest:
1132     return bitc::COMDAT_SELECTION_KIND_LARGEST;
1133   case Comdat::NoDuplicates:
1134     return bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES;
1135   case Comdat::SameSize:
1136     return bitc::COMDAT_SELECTION_KIND_SAME_SIZE;
1137   }
1138   llvm_unreachable("Invalid selection kind");
1139 }
1140 
1141 static unsigned getEncodedUnnamedAddr(const GlobalValue &GV) {
1142   switch (GV.getUnnamedAddr()) {
1143   case GlobalValue::UnnamedAddr::None:   return 0;
1144   case GlobalValue::UnnamedAddr::Local:  return 2;
1145   case GlobalValue::UnnamedAddr::Global: return 1;
1146   }
1147   llvm_unreachable("Invalid unnamed_addr");
1148 }
1149 
1150 size_t ModuleBitcodeWriter::addToStrtab(StringRef Str) {
1151   if (GenerateHash)
1152     Hasher.update(Str);
1153   return StrtabBuilder.add(Str);
1154 }
1155 
1156 void ModuleBitcodeWriter::writeComdats() {
1157   SmallVector<unsigned, 64> Vals;
1158   for (const Comdat *C : VE.getComdats()) {
1159     // COMDAT: [strtab offset, strtab size, selection_kind]
1160     Vals.push_back(addToStrtab(C->getName()));
1161     Vals.push_back(C->getName().size());
1162     Vals.push_back(getEncodedComdatSelectionKind(*C));
1163     Stream.EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
1164     Vals.clear();
1165   }
1166 }
1167 
1168 /// Write a record that will eventually hold the word offset of the
1169 /// module-level VST. For now the offset is 0, which will be backpatched
1170 /// after the real VST is written. Saves the bit offset to backpatch.
1171 void ModuleBitcodeWriter::writeValueSymbolTableForwardDecl() {
1172   // Write a placeholder value in for the offset of the real VST,
1173   // which is written after the function blocks so that it can include
1174   // the offset of each function. The placeholder offset will be
1175   // updated when the real VST is written.
1176   auto Abbv = std::make_shared<BitCodeAbbrev>();
1177   Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_VSTOFFSET));
1178   // Blocks are 32-bit aligned, so we can use a 32-bit word offset to
1179   // hold the real VST offset. Must use fixed instead of VBR as we don't
1180   // know how many VBR chunks to reserve ahead of time.
1181   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
1182   unsigned VSTOffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1183 
1184   // Emit the placeholder
1185   uint64_t Vals[] = {bitc::MODULE_CODE_VSTOFFSET, 0};
1186   Stream.EmitRecordWithAbbrev(VSTOffsetAbbrev, Vals);
1187 
1188   // Compute and save the bit offset to the placeholder, which will be
1189   // patched when the real VST is written. We can simply subtract the 32-bit
1190   // fixed size from the current bit number to get the location to backpatch.
1191   VSTOffsetPlaceholder = Stream.GetCurrentBitNo() - 32;
1192 }
1193 
1194 enum StringEncoding { SE_Char6, SE_Fixed7, SE_Fixed8 };
1195 
1196 /// Determine the encoding to use for the given string name and length.
1197 static StringEncoding getStringEncoding(StringRef Str) {
1198   bool isChar6 = true;
1199   for (char C : Str) {
1200     if (isChar6)
1201       isChar6 = BitCodeAbbrevOp::isChar6(C);
1202     if ((unsigned char)C & 128)
1203       // don't bother scanning the rest.
1204       return SE_Fixed8;
1205   }
1206   if (isChar6)
1207     return SE_Char6;
1208   return SE_Fixed7;
1209 }
1210 
1211 /// Emit top-level description of module, including target triple, inline asm,
1212 /// descriptors for global variables, and function prototype info.
1213 /// Returns the bit offset to backpatch with the location of the real VST.
1214 void ModuleBitcodeWriter::writeModuleInfo() {
1215   // Emit various pieces of data attached to a module.
1216   if (!M.getTargetTriple().empty())
1217     writeStringRecord(Stream, bitc::MODULE_CODE_TRIPLE, M.getTargetTriple(),
1218                       0 /*TODO*/);
1219   const std::string &DL = M.getDataLayoutStr();
1220   if (!DL.empty())
1221     writeStringRecord(Stream, bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/);
1222   if (!M.getModuleInlineAsm().empty())
1223     writeStringRecord(Stream, bitc::MODULE_CODE_ASM, M.getModuleInlineAsm(),
1224                       0 /*TODO*/);
1225 
1226   // Emit information about sections and GC, computing how many there are. Also
1227   // compute the maximum alignment value.
1228   std::map<std::string, unsigned> SectionMap;
1229   std::map<std::string, unsigned> GCMap;
1230   MaybeAlign MaxAlignment;
1231   unsigned MaxGlobalType = 0;
1232   const auto UpdateMaxAlignment = [&MaxAlignment](const MaybeAlign A) {
1233     if (A)
1234       MaxAlignment = !MaxAlignment ? *A : std::max(*MaxAlignment, *A);
1235   };
1236   for (const GlobalVariable &GV : M.globals()) {
1237     UpdateMaxAlignment(GV.getAlign());
1238     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getValueType()));
1239     if (GV.hasSection()) {
1240       // Give section names unique ID's.
1241       unsigned &Entry = SectionMap[std::string(GV.getSection())];
1242       if (!Entry) {
1243         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
1244                           0 /*TODO*/);
1245         Entry = SectionMap.size();
1246       }
1247     }
1248   }
1249   for (const Function &F : M) {
1250     UpdateMaxAlignment(F.getAlign());
1251     if (F.hasSection()) {
1252       // Give section names unique ID's.
1253       unsigned &Entry = SectionMap[std::string(F.getSection())];
1254       if (!Entry) {
1255         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
1256                           0 /*TODO*/);
1257         Entry = SectionMap.size();
1258       }
1259     }
1260     if (F.hasGC()) {
1261       // Same for GC names.
1262       unsigned &Entry = GCMap[F.getGC()];
1263       if (!Entry) {
1264         writeStringRecord(Stream, bitc::MODULE_CODE_GCNAME, F.getGC(),
1265                           0 /*TODO*/);
1266         Entry = GCMap.size();
1267       }
1268     }
1269   }
1270 
1271   // Emit abbrev for globals, now that we know # sections and max alignment.
1272   unsigned SimpleGVarAbbrev = 0;
1273   if (!M.global_empty()) {
1274     // Add an abbrev for common globals with no visibility or thread localness.
1275     auto Abbv = std::make_shared<BitCodeAbbrev>();
1276     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
1277     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1278     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1279     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1280                               Log2_32_Ceil(MaxGlobalType+1)));
1281     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddrSpace << 2
1282                                                            //| explicitType << 1
1283                                                            //| constant
1284     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Initializer.
1285     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // Linkage.
1286     if (!MaxAlignment)                                     // Alignment.
1287       Abbv->Add(BitCodeAbbrevOp(0));
1288     else {
1289       unsigned MaxEncAlignment = getEncodedAlign(MaxAlignment);
1290       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1291                                Log2_32_Ceil(MaxEncAlignment+1)));
1292     }
1293     if (SectionMap.empty())                                    // Section.
1294       Abbv->Add(BitCodeAbbrevOp(0));
1295     else
1296       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1297                                Log2_32_Ceil(SectionMap.size()+1)));
1298     // Don't bother emitting vis + thread local.
1299     SimpleGVarAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1300   }
1301 
1302   SmallVector<unsigned, 64> Vals;
1303   // Emit the module's source file name.
1304   {
1305     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
1306     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
1307     if (Bits == SE_Char6)
1308       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
1309     else if (Bits == SE_Fixed7)
1310       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
1311 
1312     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
1313     auto Abbv = std::make_shared<BitCodeAbbrev>();
1314     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
1315     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1316     Abbv->Add(AbbrevOpToUse);
1317     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1318 
1319     for (const auto P : M.getSourceFileName())
1320       Vals.push_back((unsigned char)P);
1321 
1322     // Emit the finished record.
1323     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
1324     Vals.clear();
1325   }
1326 
1327   // Emit the global variable information.
1328   for (const GlobalVariable &GV : M.globals()) {
1329     unsigned AbbrevToUse = 0;
1330 
1331     // GLOBALVAR: [strtab offset, strtab size, type, isconst, initid,
1332     //             linkage, alignment, section, visibility, threadlocal,
1333     //             unnamed_addr, externally_initialized, dllstorageclass,
1334     //             comdat, attributes, DSO_Local]
1335     Vals.push_back(addToStrtab(GV.getName()));
1336     Vals.push_back(GV.getName().size());
1337     Vals.push_back(VE.getTypeID(GV.getValueType()));
1338     Vals.push_back(GV.getType()->getAddressSpace() << 2 | 2 | GV.isConstant());
1339     Vals.push_back(GV.isDeclaration() ? 0 :
1340                    (VE.getValueID(GV.getInitializer()) + 1));
1341     Vals.push_back(getEncodedLinkage(GV));
1342     Vals.push_back(getEncodedAlign(GV.getAlign()));
1343     Vals.push_back(GV.hasSection() ? SectionMap[std::string(GV.getSection())]
1344                                    : 0);
1345     if (GV.isThreadLocal() ||
1346         GV.getVisibility() != GlobalValue::DefaultVisibility ||
1347         GV.getUnnamedAddr() != GlobalValue::UnnamedAddr::None ||
1348         GV.isExternallyInitialized() ||
1349         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
1350         GV.hasComdat() ||
1351         GV.hasAttributes() ||
1352         GV.isDSOLocal() ||
1353         GV.hasPartition()) {
1354       Vals.push_back(getEncodedVisibility(GV));
1355       Vals.push_back(getEncodedThreadLocalMode(GV));
1356       Vals.push_back(getEncodedUnnamedAddr(GV));
1357       Vals.push_back(GV.isExternallyInitialized());
1358       Vals.push_back(getEncodedDLLStorageClass(GV));
1359       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
1360 
1361       auto AL = GV.getAttributesAsList(AttributeList::FunctionIndex);
1362       Vals.push_back(VE.getAttributeListID(AL));
1363 
1364       Vals.push_back(GV.isDSOLocal());
1365       Vals.push_back(addToStrtab(GV.getPartition()));
1366       Vals.push_back(GV.getPartition().size());
1367     } else {
1368       AbbrevToUse = SimpleGVarAbbrev;
1369     }
1370 
1371     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
1372     Vals.clear();
1373   }
1374 
1375   // Emit the function proto information.
1376   for (const Function &F : M) {
1377     // FUNCTION:  [strtab offset, strtab size, type, callingconv, isproto,
1378     //             linkage, paramattrs, alignment, section, visibility, gc,
1379     //             unnamed_addr, prologuedata, dllstorageclass, comdat,
1380     //             prefixdata, personalityfn, DSO_Local, addrspace]
1381     Vals.push_back(addToStrtab(F.getName()));
1382     Vals.push_back(F.getName().size());
1383     Vals.push_back(VE.getTypeID(F.getFunctionType()));
1384     Vals.push_back(F.getCallingConv());
1385     Vals.push_back(F.isDeclaration());
1386     Vals.push_back(getEncodedLinkage(F));
1387     Vals.push_back(VE.getAttributeListID(F.getAttributes()));
1388     Vals.push_back(getEncodedAlign(F.getAlign()));
1389     Vals.push_back(F.hasSection() ? SectionMap[std::string(F.getSection())]
1390                                   : 0);
1391     Vals.push_back(getEncodedVisibility(F));
1392     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
1393     Vals.push_back(getEncodedUnnamedAddr(F));
1394     Vals.push_back(F.hasPrologueData() ? (VE.getValueID(F.getPrologueData()) + 1)
1395                                        : 0);
1396     Vals.push_back(getEncodedDLLStorageClass(F));
1397     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
1398     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
1399                                      : 0);
1400     Vals.push_back(
1401         F.hasPersonalityFn() ? (VE.getValueID(F.getPersonalityFn()) + 1) : 0);
1402 
1403     Vals.push_back(F.isDSOLocal());
1404     Vals.push_back(F.getAddressSpace());
1405     Vals.push_back(addToStrtab(F.getPartition()));
1406     Vals.push_back(F.getPartition().size());
1407 
1408     unsigned AbbrevToUse = 0;
1409     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
1410     Vals.clear();
1411   }
1412 
1413   // Emit the alias information.
1414   for (const GlobalAlias &A : M.aliases()) {
1415     // ALIAS: [strtab offset, strtab size, alias type, aliasee val#, linkage,
1416     //         visibility, dllstorageclass, threadlocal, unnamed_addr,
1417     //         DSO_Local]
1418     Vals.push_back(addToStrtab(A.getName()));
1419     Vals.push_back(A.getName().size());
1420     Vals.push_back(VE.getTypeID(A.getValueType()));
1421     Vals.push_back(A.getType()->getAddressSpace());
1422     Vals.push_back(VE.getValueID(A.getAliasee()));
1423     Vals.push_back(getEncodedLinkage(A));
1424     Vals.push_back(getEncodedVisibility(A));
1425     Vals.push_back(getEncodedDLLStorageClass(A));
1426     Vals.push_back(getEncodedThreadLocalMode(A));
1427     Vals.push_back(getEncodedUnnamedAddr(A));
1428     Vals.push_back(A.isDSOLocal());
1429     Vals.push_back(addToStrtab(A.getPartition()));
1430     Vals.push_back(A.getPartition().size());
1431 
1432     unsigned AbbrevToUse = 0;
1433     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
1434     Vals.clear();
1435   }
1436 
1437   // Emit the ifunc information.
1438   for (const GlobalIFunc &I : M.ifuncs()) {
1439     // IFUNC: [strtab offset, strtab size, ifunc type, address space, resolver
1440     //         val#, linkage, visibility, DSO_Local]
1441     Vals.push_back(addToStrtab(I.getName()));
1442     Vals.push_back(I.getName().size());
1443     Vals.push_back(VE.getTypeID(I.getValueType()));
1444     Vals.push_back(I.getType()->getAddressSpace());
1445     Vals.push_back(VE.getValueID(I.getResolver()));
1446     Vals.push_back(getEncodedLinkage(I));
1447     Vals.push_back(getEncodedVisibility(I));
1448     Vals.push_back(I.isDSOLocal());
1449     Vals.push_back(addToStrtab(I.getPartition()));
1450     Vals.push_back(I.getPartition().size());
1451     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
1452     Vals.clear();
1453   }
1454 
1455   writeValueSymbolTableForwardDecl();
1456 }
1457 
1458 static uint64_t getOptimizationFlags(const Value *V) {
1459   uint64_t Flags = 0;
1460 
1461   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
1462     if (OBO->hasNoSignedWrap())
1463       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
1464     if (OBO->hasNoUnsignedWrap())
1465       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
1466   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
1467     if (PEO->isExact())
1468       Flags |= 1 << bitc::PEO_EXACT;
1469   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
1470     if (FPMO->hasAllowReassoc())
1471       Flags |= bitc::AllowReassoc;
1472     if (FPMO->hasNoNaNs())
1473       Flags |= bitc::NoNaNs;
1474     if (FPMO->hasNoInfs())
1475       Flags |= bitc::NoInfs;
1476     if (FPMO->hasNoSignedZeros())
1477       Flags |= bitc::NoSignedZeros;
1478     if (FPMO->hasAllowReciprocal())
1479       Flags |= bitc::AllowReciprocal;
1480     if (FPMO->hasAllowContract())
1481       Flags |= bitc::AllowContract;
1482     if (FPMO->hasApproxFunc())
1483       Flags |= bitc::ApproxFunc;
1484   }
1485 
1486   return Flags;
1487 }
1488 
1489 void ModuleBitcodeWriter::writeValueAsMetadata(
1490     const ValueAsMetadata *MD, SmallVectorImpl<uint64_t> &Record) {
1491   // Mimic an MDNode with a value as one operand.
1492   Value *V = MD->getValue();
1493   Record.push_back(VE.getTypeID(V->getType()));
1494   Record.push_back(VE.getValueID(V));
1495   Stream.EmitRecord(bitc::METADATA_VALUE, Record, 0);
1496   Record.clear();
1497 }
1498 
1499 void ModuleBitcodeWriter::writeMDTuple(const MDTuple *N,
1500                                        SmallVectorImpl<uint64_t> &Record,
1501                                        unsigned Abbrev) {
1502   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
1503     Metadata *MD = N->getOperand(i);
1504     assert(!(MD && isa<LocalAsMetadata>(MD)) &&
1505            "Unexpected function-local metadata");
1506     Record.push_back(VE.getMetadataOrNullID(MD));
1507   }
1508   Stream.EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
1509                                     : bitc::METADATA_NODE,
1510                     Record, Abbrev);
1511   Record.clear();
1512 }
1513 
1514 unsigned ModuleBitcodeWriter::createDILocationAbbrev() {
1515   // Assume the column is usually under 128, and always output the inlined-at
1516   // location (it's never more expensive than building an array size 1).
1517   auto Abbv = std::make_shared<BitCodeAbbrev>();
1518   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
1519   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1520   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1521   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1522   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1523   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1524   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1525   return Stream.EmitAbbrev(std::move(Abbv));
1526 }
1527 
1528 void ModuleBitcodeWriter::writeDILocation(const DILocation *N,
1529                                           SmallVectorImpl<uint64_t> &Record,
1530                                           unsigned &Abbrev) {
1531   if (!Abbrev)
1532     Abbrev = createDILocationAbbrev();
1533 
1534   Record.push_back(N->isDistinct());
1535   Record.push_back(N->getLine());
1536   Record.push_back(N->getColumn());
1537   Record.push_back(VE.getMetadataID(N->getScope()));
1538   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
1539   Record.push_back(N->isImplicitCode());
1540 
1541   Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
1542   Record.clear();
1543 }
1544 
1545 unsigned ModuleBitcodeWriter::createGenericDINodeAbbrev() {
1546   // Assume the column is usually under 128, and always output the inlined-at
1547   // location (it's never more expensive than building an array size 1).
1548   auto Abbv = std::make_shared<BitCodeAbbrev>();
1549   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
1550   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1551   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1552   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1553   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1554   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1555   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1556   return Stream.EmitAbbrev(std::move(Abbv));
1557 }
1558 
1559 void ModuleBitcodeWriter::writeGenericDINode(const GenericDINode *N,
1560                                              SmallVectorImpl<uint64_t> &Record,
1561                                              unsigned &Abbrev) {
1562   if (!Abbrev)
1563     Abbrev = createGenericDINodeAbbrev();
1564 
1565   Record.push_back(N->isDistinct());
1566   Record.push_back(N->getTag());
1567   Record.push_back(0); // Per-tag version field; unused for now.
1568 
1569   for (auto &I : N->operands())
1570     Record.push_back(VE.getMetadataOrNullID(I));
1571 
1572   Stream.EmitRecord(bitc::METADATA_GENERIC_DEBUG, Record, Abbrev);
1573   Record.clear();
1574 }
1575 
1576 void ModuleBitcodeWriter::writeDISubrange(const DISubrange *N,
1577                                           SmallVectorImpl<uint64_t> &Record,
1578                                           unsigned Abbrev) {
1579   const uint64_t Version = 2 << 1;
1580   Record.push_back((uint64_t)N->isDistinct() | Version);
1581   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1582   Record.push_back(VE.getMetadataOrNullID(N->getRawLowerBound()));
1583   Record.push_back(VE.getMetadataOrNullID(N->getRawUpperBound()));
1584   Record.push_back(VE.getMetadataOrNullID(N->getRawStride()));
1585 
1586   Stream.EmitRecord(bitc::METADATA_SUBRANGE, Record, Abbrev);
1587   Record.clear();
1588 }
1589 
1590 void ModuleBitcodeWriter::writeDIGenericSubrange(
1591     const DIGenericSubrange *N, SmallVectorImpl<uint64_t> &Record,
1592     unsigned Abbrev) {
1593   Record.push_back((uint64_t)N->isDistinct());
1594   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1595   Record.push_back(VE.getMetadataOrNullID(N->getRawLowerBound()));
1596   Record.push_back(VE.getMetadataOrNullID(N->getRawUpperBound()));
1597   Record.push_back(VE.getMetadataOrNullID(N->getRawStride()));
1598 
1599   Stream.EmitRecord(bitc::METADATA_GENERIC_SUBRANGE, Record, Abbrev);
1600   Record.clear();
1601 }
1602 
1603 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
1604   if ((int64_t)V >= 0)
1605     Vals.push_back(V << 1);
1606   else
1607     Vals.push_back((-V << 1) | 1);
1608 }
1609 
1610 static void emitWideAPInt(SmallVectorImpl<uint64_t> &Vals, const APInt &A) {
1611   // We have an arbitrary precision integer value to write whose
1612   // bit width is > 64. However, in canonical unsigned integer
1613   // format it is likely that the high bits are going to be zero.
1614   // So, we only write the number of active words.
1615   unsigned NumWords = A.getActiveWords();
1616   const uint64_t *RawData = A.getRawData();
1617   for (unsigned i = 0; i < NumWords; i++)
1618     emitSignedInt64(Vals, RawData[i]);
1619 }
1620 
1621 void ModuleBitcodeWriter::writeDIEnumerator(const DIEnumerator *N,
1622                                             SmallVectorImpl<uint64_t> &Record,
1623                                             unsigned Abbrev) {
1624   const uint64_t IsBigInt = 1 << 2;
1625   Record.push_back(IsBigInt | (N->isUnsigned() << 1) | N->isDistinct());
1626   Record.push_back(N->getValue().getBitWidth());
1627   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1628   emitWideAPInt(Record, N->getValue());
1629 
1630   Stream.EmitRecord(bitc::METADATA_ENUMERATOR, Record, Abbrev);
1631   Record.clear();
1632 }
1633 
1634 void ModuleBitcodeWriter::writeDIBasicType(const DIBasicType *N,
1635                                            SmallVectorImpl<uint64_t> &Record,
1636                                            unsigned Abbrev) {
1637   Record.push_back(N->isDistinct());
1638   Record.push_back(N->getTag());
1639   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1640   Record.push_back(N->getSizeInBits());
1641   Record.push_back(N->getAlignInBits());
1642   Record.push_back(N->getEncoding());
1643   Record.push_back(N->getFlags());
1644 
1645   Stream.EmitRecord(bitc::METADATA_BASIC_TYPE, Record, Abbrev);
1646   Record.clear();
1647 }
1648 
1649 void ModuleBitcodeWriter::writeDIStringType(const DIStringType *N,
1650                                             SmallVectorImpl<uint64_t> &Record,
1651                                             unsigned Abbrev) {
1652   Record.push_back(N->isDistinct());
1653   Record.push_back(N->getTag());
1654   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1655   Record.push_back(VE.getMetadataOrNullID(N->getStringLength()));
1656   Record.push_back(VE.getMetadataOrNullID(N->getStringLengthExp()));
1657   Record.push_back(N->getSizeInBits());
1658   Record.push_back(N->getAlignInBits());
1659   Record.push_back(N->getEncoding());
1660 
1661   Stream.EmitRecord(bitc::METADATA_STRING_TYPE, Record, Abbrev);
1662   Record.clear();
1663 }
1664 
1665 void ModuleBitcodeWriter::writeDIDerivedType(const DIDerivedType *N,
1666                                              SmallVectorImpl<uint64_t> &Record,
1667                                              unsigned Abbrev) {
1668   Record.push_back(N->isDistinct());
1669   Record.push_back(N->getTag());
1670   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1671   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1672   Record.push_back(N->getLine());
1673   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1674   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1675   Record.push_back(N->getSizeInBits());
1676   Record.push_back(N->getAlignInBits());
1677   Record.push_back(N->getOffsetInBits());
1678   Record.push_back(N->getFlags());
1679   Record.push_back(VE.getMetadataOrNullID(N->getExtraData()));
1680 
1681   // DWARF address space is encoded as N->getDWARFAddressSpace() + 1. 0 means
1682   // that there is no DWARF address space associated with DIDerivedType.
1683   if (const auto &DWARFAddressSpace = N->getDWARFAddressSpace())
1684     Record.push_back(*DWARFAddressSpace + 1);
1685   else
1686     Record.push_back(0);
1687 
1688   Stream.EmitRecord(bitc::METADATA_DERIVED_TYPE, Record, Abbrev);
1689   Record.clear();
1690 }
1691 
1692 void ModuleBitcodeWriter::writeDICompositeType(
1693     const DICompositeType *N, SmallVectorImpl<uint64_t> &Record,
1694     unsigned Abbrev) {
1695   const unsigned IsNotUsedInOldTypeRef = 0x2;
1696   Record.push_back(IsNotUsedInOldTypeRef | (unsigned)N->isDistinct());
1697   Record.push_back(N->getTag());
1698   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1699   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1700   Record.push_back(N->getLine());
1701   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1702   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1703   Record.push_back(N->getSizeInBits());
1704   Record.push_back(N->getAlignInBits());
1705   Record.push_back(N->getOffsetInBits());
1706   Record.push_back(N->getFlags());
1707   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1708   Record.push_back(N->getRuntimeLang());
1709   Record.push_back(VE.getMetadataOrNullID(N->getVTableHolder()));
1710   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1711   Record.push_back(VE.getMetadataOrNullID(N->getRawIdentifier()));
1712   Record.push_back(VE.getMetadataOrNullID(N->getDiscriminator()));
1713   Record.push_back(VE.getMetadataOrNullID(N->getRawDataLocation()));
1714   Record.push_back(VE.getMetadataOrNullID(N->getRawAssociated()));
1715   Record.push_back(VE.getMetadataOrNullID(N->getRawAllocated()));
1716   Record.push_back(VE.getMetadataOrNullID(N->getRawRank()));
1717 
1718   Stream.EmitRecord(bitc::METADATA_COMPOSITE_TYPE, Record, Abbrev);
1719   Record.clear();
1720 }
1721 
1722 void ModuleBitcodeWriter::writeDISubroutineType(
1723     const DISubroutineType *N, SmallVectorImpl<uint64_t> &Record,
1724     unsigned Abbrev) {
1725   const unsigned HasNoOldTypeRefs = 0x2;
1726   Record.push_back(HasNoOldTypeRefs | (unsigned)N->isDistinct());
1727   Record.push_back(N->getFlags());
1728   Record.push_back(VE.getMetadataOrNullID(N->getTypeArray().get()));
1729   Record.push_back(N->getCC());
1730 
1731   Stream.EmitRecord(bitc::METADATA_SUBROUTINE_TYPE, Record, Abbrev);
1732   Record.clear();
1733 }
1734 
1735 void ModuleBitcodeWriter::writeDIFile(const DIFile *N,
1736                                       SmallVectorImpl<uint64_t> &Record,
1737                                       unsigned Abbrev) {
1738   Record.push_back(N->isDistinct());
1739   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
1740   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
1741   if (N->getRawChecksum()) {
1742     Record.push_back(N->getRawChecksum()->Kind);
1743     Record.push_back(VE.getMetadataOrNullID(N->getRawChecksum()->Value));
1744   } else {
1745     // Maintain backwards compatibility with the old internal representation of
1746     // CSK_None in ChecksumKind by writing nulls here when Checksum is None.
1747     Record.push_back(0);
1748     Record.push_back(VE.getMetadataOrNullID(nullptr));
1749   }
1750   auto Source = N->getRawSource();
1751   if (Source)
1752     Record.push_back(VE.getMetadataOrNullID(*Source));
1753 
1754   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
1755   Record.clear();
1756 }
1757 
1758 void ModuleBitcodeWriter::writeDICompileUnit(const DICompileUnit *N,
1759                                              SmallVectorImpl<uint64_t> &Record,
1760                                              unsigned Abbrev) {
1761   Record.push_back(/* IsDistinct */ true);
1762   Record.push_back(N->getSourceLanguage());
1763   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1764   Record.push_back(VE.getMetadataOrNullID(N->getRawProducer()));
1765   Record.push_back(N->isOptimized());
1766   Record.push_back(VE.getMetadataOrNullID(N->getRawFlags()));
1767   Record.push_back(N->getRuntimeVersion());
1768   Record.push_back(VE.getMetadataOrNullID(N->getRawSplitDebugFilename()));
1769   Record.push_back(N->getEmissionKind());
1770   Record.push_back(VE.getMetadataOrNullID(N->getEnumTypes().get()));
1771   Record.push_back(VE.getMetadataOrNullID(N->getRetainedTypes().get()));
1772   Record.push_back(/* subprograms */ 0);
1773   Record.push_back(VE.getMetadataOrNullID(N->getGlobalVariables().get()));
1774   Record.push_back(VE.getMetadataOrNullID(N->getImportedEntities().get()));
1775   Record.push_back(N->getDWOId());
1776   Record.push_back(VE.getMetadataOrNullID(N->getMacros().get()));
1777   Record.push_back(N->getSplitDebugInlining());
1778   Record.push_back(N->getDebugInfoForProfiling());
1779   Record.push_back((unsigned)N->getNameTableKind());
1780   Record.push_back(N->getRangesBaseAddress());
1781   Record.push_back(VE.getMetadataOrNullID(N->getRawSysRoot()));
1782   Record.push_back(VE.getMetadataOrNullID(N->getRawSDK()));
1783 
1784   Stream.EmitRecord(bitc::METADATA_COMPILE_UNIT, Record, Abbrev);
1785   Record.clear();
1786 }
1787 
1788 void ModuleBitcodeWriter::writeDISubprogram(const DISubprogram *N,
1789                                             SmallVectorImpl<uint64_t> &Record,
1790                                             unsigned Abbrev) {
1791   const uint64_t HasUnitFlag = 1 << 1;
1792   const uint64_t HasSPFlagsFlag = 1 << 2;
1793   Record.push_back(uint64_t(N->isDistinct()) | HasUnitFlag | HasSPFlagsFlag);
1794   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1795   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1796   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1797   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1798   Record.push_back(N->getLine());
1799   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1800   Record.push_back(N->getScopeLine());
1801   Record.push_back(VE.getMetadataOrNullID(N->getContainingType()));
1802   Record.push_back(N->getSPFlags());
1803   Record.push_back(N->getVirtualIndex());
1804   Record.push_back(N->getFlags());
1805   Record.push_back(VE.getMetadataOrNullID(N->getRawUnit()));
1806   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1807   Record.push_back(VE.getMetadataOrNullID(N->getDeclaration()));
1808   Record.push_back(VE.getMetadataOrNullID(N->getRetainedNodes().get()));
1809   Record.push_back(N->getThisAdjustment());
1810   Record.push_back(VE.getMetadataOrNullID(N->getThrownTypes().get()));
1811 
1812   Stream.EmitRecord(bitc::METADATA_SUBPROGRAM, Record, Abbrev);
1813   Record.clear();
1814 }
1815 
1816 void ModuleBitcodeWriter::writeDILexicalBlock(const DILexicalBlock *N,
1817                                               SmallVectorImpl<uint64_t> &Record,
1818                                               unsigned Abbrev) {
1819   Record.push_back(N->isDistinct());
1820   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1821   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1822   Record.push_back(N->getLine());
1823   Record.push_back(N->getColumn());
1824 
1825   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK, Record, Abbrev);
1826   Record.clear();
1827 }
1828 
1829 void ModuleBitcodeWriter::writeDILexicalBlockFile(
1830     const DILexicalBlockFile *N, SmallVectorImpl<uint64_t> &Record,
1831     unsigned Abbrev) {
1832   Record.push_back(N->isDistinct());
1833   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1834   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1835   Record.push_back(N->getDiscriminator());
1836 
1837   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK_FILE, Record, Abbrev);
1838   Record.clear();
1839 }
1840 
1841 void ModuleBitcodeWriter::writeDICommonBlock(const DICommonBlock *N,
1842                                              SmallVectorImpl<uint64_t> &Record,
1843                                              unsigned Abbrev) {
1844   Record.push_back(N->isDistinct());
1845   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1846   Record.push_back(VE.getMetadataOrNullID(N->getDecl()));
1847   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1848   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1849   Record.push_back(N->getLineNo());
1850 
1851   Stream.EmitRecord(bitc::METADATA_COMMON_BLOCK, Record, Abbrev);
1852   Record.clear();
1853 }
1854 
1855 void ModuleBitcodeWriter::writeDINamespace(const DINamespace *N,
1856                                            SmallVectorImpl<uint64_t> &Record,
1857                                            unsigned Abbrev) {
1858   Record.push_back(N->isDistinct() | N->getExportSymbols() << 1);
1859   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1860   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1861 
1862   Stream.EmitRecord(bitc::METADATA_NAMESPACE, Record, Abbrev);
1863   Record.clear();
1864 }
1865 
1866 void ModuleBitcodeWriter::writeDIMacro(const DIMacro *N,
1867                                        SmallVectorImpl<uint64_t> &Record,
1868                                        unsigned Abbrev) {
1869   Record.push_back(N->isDistinct());
1870   Record.push_back(N->getMacinfoType());
1871   Record.push_back(N->getLine());
1872   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1873   Record.push_back(VE.getMetadataOrNullID(N->getRawValue()));
1874 
1875   Stream.EmitRecord(bitc::METADATA_MACRO, Record, Abbrev);
1876   Record.clear();
1877 }
1878 
1879 void ModuleBitcodeWriter::writeDIMacroFile(const DIMacroFile *N,
1880                                            SmallVectorImpl<uint64_t> &Record,
1881                                            unsigned Abbrev) {
1882   Record.push_back(N->isDistinct());
1883   Record.push_back(N->getMacinfoType());
1884   Record.push_back(N->getLine());
1885   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1886   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1887 
1888   Stream.EmitRecord(bitc::METADATA_MACRO_FILE, Record, Abbrev);
1889   Record.clear();
1890 }
1891 
1892 void ModuleBitcodeWriter::writeDIArgList(const DIArgList *N,
1893                                          SmallVectorImpl<uint64_t> &Record,
1894                                          unsigned Abbrev) {
1895   Record.reserve(N->getArgs().size());
1896   for (ValueAsMetadata *MD : N->getArgs())
1897     Record.push_back(VE.getMetadataID(MD));
1898 
1899   Stream.EmitRecord(bitc::METADATA_ARG_LIST, Record, Abbrev);
1900   Record.clear();
1901 }
1902 
1903 void ModuleBitcodeWriter::writeDIModule(const DIModule *N,
1904                                         SmallVectorImpl<uint64_t> &Record,
1905                                         unsigned Abbrev) {
1906   Record.push_back(N->isDistinct());
1907   for (auto &I : N->operands())
1908     Record.push_back(VE.getMetadataOrNullID(I));
1909   Record.push_back(N->getLineNo());
1910   Record.push_back(N->getIsDecl());
1911 
1912   Stream.EmitRecord(bitc::METADATA_MODULE, Record, Abbrev);
1913   Record.clear();
1914 }
1915 
1916 void ModuleBitcodeWriter::writeDITemplateTypeParameter(
1917     const DITemplateTypeParameter *N, SmallVectorImpl<uint64_t> &Record,
1918     unsigned Abbrev) {
1919   Record.push_back(N->isDistinct());
1920   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1921   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1922   Record.push_back(N->isDefault());
1923 
1924   Stream.EmitRecord(bitc::METADATA_TEMPLATE_TYPE, Record, Abbrev);
1925   Record.clear();
1926 }
1927 
1928 void ModuleBitcodeWriter::writeDITemplateValueParameter(
1929     const DITemplateValueParameter *N, SmallVectorImpl<uint64_t> &Record,
1930     unsigned Abbrev) {
1931   Record.push_back(N->isDistinct());
1932   Record.push_back(N->getTag());
1933   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1934   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1935   Record.push_back(N->isDefault());
1936   Record.push_back(VE.getMetadataOrNullID(N->getValue()));
1937 
1938   Stream.EmitRecord(bitc::METADATA_TEMPLATE_VALUE, Record, Abbrev);
1939   Record.clear();
1940 }
1941 
1942 void ModuleBitcodeWriter::writeDIGlobalVariable(
1943     const DIGlobalVariable *N, SmallVectorImpl<uint64_t> &Record,
1944     unsigned Abbrev) {
1945   const uint64_t Version = 2 << 1;
1946   Record.push_back((uint64_t)N->isDistinct() | Version);
1947   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1948   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1949   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1950   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1951   Record.push_back(N->getLine());
1952   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1953   Record.push_back(N->isLocalToUnit());
1954   Record.push_back(N->isDefinition());
1955   Record.push_back(VE.getMetadataOrNullID(N->getStaticDataMemberDeclaration()));
1956   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams()));
1957   Record.push_back(N->getAlignInBits());
1958 
1959   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR, Record, Abbrev);
1960   Record.clear();
1961 }
1962 
1963 void ModuleBitcodeWriter::writeDILocalVariable(
1964     const DILocalVariable *N, SmallVectorImpl<uint64_t> &Record,
1965     unsigned Abbrev) {
1966   // In order to support all possible bitcode formats in BitcodeReader we need
1967   // to distinguish the following cases:
1968   // 1) Record has no artificial tag (Record[1]),
1969   //   has no obsolete inlinedAt field (Record[9]).
1970   //   In this case Record size will be 8, HasAlignment flag is false.
1971   // 2) Record has artificial tag (Record[1]),
1972   //   has no obsolete inlignedAt field (Record[9]).
1973   //   In this case Record size will be 9, HasAlignment flag is false.
1974   // 3) Record has both artificial tag (Record[1]) and
1975   //   obsolete inlignedAt field (Record[9]).
1976   //   In this case Record size will be 10, HasAlignment flag is false.
1977   // 4) Record has neither artificial tag, nor inlignedAt field, but
1978   //   HasAlignment flag is true and Record[8] contains alignment value.
1979   const uint64_t HasAlignmentFlag = 1 << 1;
1980   Record.push_back((uint64_t)N->isDistinct() | HasAlignmentFlag);
1981   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1982   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1983   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1984   Record.push_back(N->getLine());
1985   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1986   Record.push_back(N->getArg());
1987   Record.push_back(N->getFlags());
1988   Record.push_back(N->getAlignInBits());
1989 
1990   Stream.EmitRecord(bitc::METADATA_LOCAL_VAR, Record, Abbrev);
1991   Record.clear();
1992 }
1993 
1994 void ModuleBitcodeWriter::writeDILabel(
1995     const DILabel *N, SmallVectorImpl<uint64_t> &Record,
1996     unsigned Abbrev) {
1997   Record.push_back((uint64_t)N->isDistinct());
1998   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1999   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2000   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2001   Record.push_back(N->getLine());
2002 
2003   Stream.EmitRecord(bitc::METADATA_LABEL, Record, Abbrev);
2004   Record.clear();
2005 }
2006 
2007 void ModuleBitcodeWriter::writeDIExpression(const DIExpression *N,
2008                                             SmallVectorImpl<uint64_t> &Record,
2009                                             unsigned Abbrev) {
2010   Record.reserve(N->getElements().size() + 1);
2011   const uint64_t Version = 4 << 1;
2012   Record.push_back((uint64_t)N->isDistinct() | Version);
2013   Record.append(N->elements_begin(), N->elements_end());
2014 
2015   Stream.EmitRecord(bitc::METADATA_EXPRESSION, Record, Abbrev);
2016   Record.clear();
2017 }
2018 
2019 void ModuleBitcodeWriter::writeDIGlobalVariableExpression(
2020     const DIGlobalVariableExpression *N, SmallVectorImpl<uint64_t> &Record,
2021     unsigned Abbrev) {
2022   Record.push_back(N->isDistinct());
2023   Record.push_back(VE.getMetadataOrNullID(N->getVariable()));
2024   Record.push_back(VE.getMetadataOrNullID(N->getExpression()));
2025 
2026   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR_EXPR, Record, Abbrev);
2027   Record.clear();
2028 }
2029 
2030 void ModuleBitcodeWriter::writeDIObjCProperty(const DIObjCProperty *N,
2031                                               SmallVectorImpl<uint64_t> &Record,
2032                                               unsigned Abbrev) {
2033   Record.push_back(N->isDistinct());
2034   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2035   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2036   Record.push_back(N->getLine());
2037   Record.push_back(VE.getMetadataOrNullID(N->getRawSetterName()));
2038   Record.push_back(VE.getMetadataOrNullID(N->getRawGetterName()));
2039   Record.push_back(N->getAttributes());
2040   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2041 
2042   Stream.EmitRecord(bitc::METADATA_OBJC_PROPERTY, Record, Abbrev);
2043   Record.clear();
2044 }
2045 
2046 void ModuleBitcodeWriter::writeDIImportedEntity(
2047     const DIImportedEntity *N, SmallVectorImpl<uint64_t> &Record,
2048     unsigned Abbrev) {
2049   Record.push_back(N->isDistinct());
2050   Record.push_back(N->getTag());
2051   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2052   Record.push_back(VE.getMetadataOrNullID(N->getEntity()));
2053   Record.push_back(N->getLine());
2054   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2055   Record.push_back(VE.getMetadataOrNullID(N->getRawFile()));
2056 
2057   Stream.EmitRecord(bitc::METADATA_IMPORTED_ENTITY, Record, Abbrev);
2058   Record.clear();
2059 }
2060 
2061 unsigned ModuleBitcodeWriter::createNamedMetadataAbbrev() {
2062   auto Abbv = std::make_shared<BitCodeAbbrev>();
2063   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
2064   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2065   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2066   return Stream.EmitAbbrev(std::move(Abbv));
2067 }
2068 
2069 void ModuleBitcodeWriter::writeNamedMetadata(
2070     SmallVectorImpl<uint64_t> &Record) {
2071   if (M.named_metadata_empty())
2072     return;
2073 
2074   unsigned Abbrev = createNamedMetadataAbbrev();
2075   for (const NamedMDNode &NMD : M.named_metadata()) {
2076     // Write name.
2077     StringRef Str = NMD.getName();
2078     Record.append(Str.bytes_begin(), Str.bytes_end());
2079     Stream.EmitRecord(bitc::METADATA_NAME, Record, Abbrev);
2080     Record.clear();
2081 
2082     // Write named metadata operands.
2083     for (const MDNode *N : NMD.operands())
2084       Record.push_back(VE.getMetadataID(N));
2085     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
2086     Record.clear();
2087   }
2088 }
2089 
2090 unsigned ModuleBitcodeWriter::createMetadataStringsAbbrev() {
2091   auto Abbv = std::make_shared<BitCodeAbbrev>();
2092   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRINGS));
2093   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // # of strings
2094   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // offset to chars
2095   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
2096   return Stream.EmitAbbrev(std::move(Abbv));
2097 }
2098 
2099 /// Write out a record for MDString.
2100 ///
2101 /// All the metadata strings in a metadata block are emitted in a single
2102 /// record.  The sizes and strings themselves are shoved into a blob.
2103 void ModuleBitcodeWriter::writeMetadataStrings(
2104     ArrayRef<const Metadata *> Strings, SmallVectorImpl<uint64_t> &Record) {
2105   if (Strings.empty())
2106     return;
2107 
2108   // Start the record with the number of strings.
2109   Record.push_back(bitc::METADATA_STRINGS);
2110   Record.push_back(Strings.size());
2111 
2112   // Emit the sizes of the strings in the blob.
2113   SmallString<256> Blob;
2114   {
2115     BitstreamWriter W(Blob);
2116     for (const Metadata *MD : Strings)
2117       W.EmitVBR(cast<MDString>(MD)->getLength(), 6);
2118     W.FlushToWord();
2119   }
2120 
2121   // Add the offset to the strings to the record.
2122   Record.push_back(Blob.size());
2123 
2124   // Add the strings to the blob.
2125   for (const Metadata *MD : Strings)
2126     Blob.append(cast<MDString>(MD)->getString());
2127 
2128   // Emit the final record.
2129   Stream.EmitRecordWithBlob(createMetadataStringsAbbrev(), Record, Blob);
2130   Record.clear();
2131 }
2132 
2133 // Generates an enum to use as an index in the Abbrev array of Metadata record.
2134 enum MetadataAbbrev : unsigned {
2135 #define HANDLE_MDNODE_LEAF(CLASS) CLASS##AbbrevID,
2136 #include "llvm/IR/Metadata.def"
2137   LastPlusOne
2138 };
2139 
2140 void ModuleBitcodeWriter::writeMetadataRecords(
2141     ArrayRef<const Metadata *> MDs, SmallVectorImpl<uint64_t> &Record,
2142     std::vector<unsigned> *MDAbbrevs, std::vector<uint64_t> *IndexPos) {
2143   if (MDs.empty())
2144     return;
2145 
2146   // Initialize MDNode abbreviations.
2147 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
2148 #include "llvm/IR/Metadata.def"
2149 
2150   for (const Metadata *MD : MDs) {
2151     if (IndexPos)
2152       IndexPos->push_back(Stream.GetCurrentBitNo());
2153     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
2154       assert(N->isResolved() && "Expected forward references to be resolved");
2155 
2156 #ifndef NDEBUG
2157       switch (N->getMetadataID()) {
2158 #define HANDLE_MDNODE_LEAF_UNIQUED(CLASS)                                      \
2159   case Metadata::CLASS##Kind:                                                  \
2160     assert(!N->isDistinct() && "Expected non-distinct " #CLASS);               \
2161     break;
2162 #define HANDLE_MDNODE_LEAF_DISTINCT(CLASS)                                     \
2163   case Metadata::CLASS##Kind:                                                  \
2164     assert(N->isDistinct() && "Expected distinct " #CLASS);                    \
2165     break;
2166 #include "llvm/IR/Metadata.def"
2167       }
2168 #endif
2169 
2170       switch (N->getMetadataID()) {
2171       default:
2172         llvm_unreachable("Invalid MDNode subclass");
2173 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
2174   case Metadata::CLASS##Kind:                                                  \
2175     if (MDAbbrevs)                                                             \
2176       write##CLASS(cast<CLASS>(N), Record,                                     \
2177                    (*MDAbbrevs)[MetadataAbbrev::CLASS##AbbrevID]);             \
2178     else                                                                       \
2179       write##CLASS(cast<CLASS>(N), Record, CLASS##Abbrev);                     \
2180     continue;
2181 #include "llvm/IR/Metadata.def"
2182       }
2183     }
2184     writeValueAsMetadata(cast<ValueAsMetadata>(MD), Record);
2185   }
2186 }
2187 
2188 void ModuleBitcodeWriter::writeModuleMetadata() {
2189   if (!VE.hasMDs() && M.named_metadata_empty())
2190     return;
2191 
2192   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 4);
2193   SmallVector<uint64_t, 64> Record;
2194 
2195   // Emit all abbrevs upfront, so that the reader can jump in the middle of the
2196   // block and load any metadata.
2197   std::vector<unsigned> MDAbbrevs;
2198 
2199   MDAbbrevs.resize(MetadataAbbrev::LastPlusOne);
2200   MDAbbrevs[MetadataAbbrev::DILocationAbbrevID] = createDILocationAbbrev();
2201   MDAbbrevs[MetadataAbbrev::GenericDINodeAbbrevID] =
2202       createGenericDINodeAbbrev();
2203 
2204   auto Abbv = std::make_shared<BitCodeAbbrev>();
2205   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX_OFFSET));
2206   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2207   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2208   unsigned OffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2209 
2210   Abbv = std::make_shared<BitCodeAbbrev>();
2211   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX));
2212   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2213   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2214   unsigned IndexAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2215 
2216   // Emit MDStrings together upfront.
2217   writeMetadataStrings(VE.getMDStrings(), Record);
2218 
2219   // We only emit an index for the metadata record if we have more than a given
2220   // (naive) threshold of metadatas, otherwise it is not worth it.
2221   if (VE.getNonMDStrings().size() > IndexThreshold) {
2222     // Write a placeholder value in for the offset of the metadata index,
2223     // which is written after the records, so that it can include
2224     // the offset of each entry. The placeholder offset will be
2225     // updated after all records are emitted.
2226     uint64_t Vals[] = {0, 0};
2227     Stream.EmitRecord(bitc::METADATA_INDEX_OFFSET, Vals, OffsetAbbrev);
2228   }
2229 
2230   // Compute and save the bit offset to the current position, which will be
2231   // patched when we emit the index later. We can simply subtract the 64-bit
2232   // fixed size from the current bit number to get the location to backpatch.
2233   uint64_t IndexOffsetRecordBitPos = Stream.GetCurrentBitNo();
2234 
2235   // This index will contain the bitpos for each individual record.
2236   std::vector<uint64_t> IndexPos;
2237   IndexPos.reserve(VE.getNonMDStrings().size());
2238 
2239   // Write all the records
2240   writeMetadataRecords(VE.getNonMDStrings(), Record, &MDAbbrevs, &IndexPos);
2241 
2242   if (VE.getNonMDStrings().size() > IndexThreshold) {
2243     // Now that we have emitted all the records we will emit the index. But
2244     // first
2245     // backpatch the forward reference so that the reader can skip the records
2246     // efficiently.
2247     Stream.BackpatchWord64(IndexOffsetRecordBitPos - 64,
2248                            Stream.GetCurrentBitNo() - IndexOffsetRecordBitPos);
2249 
2250     // Delta encode the index.
2251     uint64_t PreviousValue = IndexOffsetRecordBitPos;
2252     for (auto &Elt : IndexPos) {
2253       auto EltDelta = Elt - PreviousValue;
2254       PreviousValue = Elt;
2255       Elt = EltDelta;
2256     }
2257     // Emit the index record.
2258     Stream.EmitRecord(bitc::METADATA_INDEX, IndexPos, IndexAbbrev);
2259     IndexPos.clear();
2260   }
2261 
2262   // Write the named metadata now.
2263   writeNamedMetadata(Record);
2264 
2265   auto AddDeclAttachedMetadata = [&](const GlobalObject &GO) {
2266     SmallVector<uint64_t, 4> Record;
2267     Record.push_back(VE.getValueID(&GO));
2268     pushGlobalMetadataAttachment(Record, GO);
2269     Stream.EmitRecord(bitc::METADATA_GLOBAL_DECL_ATTACHMENT, Record);
2270   };
2271   for (const Function &F : M)
2272     if (F.isDeclaration() && F.hasMetadata())
2273       AddDeclAttachedMetadata(F);
2274   // FIXME: Only store metadata for declarations here, and move data for global
2275   // variable definitions to a separate block (PR28134).
2276   for (const GlobalVariable &GV : M.globals())
2277     if (GV.hasMetadata())
2278       AddDeclAttachedMetadata(GV);
2279 
2280   Stream.ExitBlock();
2281 }
2282 
2283 void ModuleBitcodeWriter::writeFunctionMetadata(const Function &F) {
2284   if (!VE.hasMDs())
2285     return;
2286 
2287   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
2288   SmallVector<uint64_t, 64> Record;
2289   writeMetadataStrings(VE.getMDStrings(), Record);
2290   writeMetadataRecords(VE.getNonMDStrings(), Record);
2291   Stream.ExitBlock();
2292 }
2293 
2294 void ModuleBitcodeWriter::pushGlobalMetadataAttachment(
2295     SmallVectorImpl<uint64_t> &Record, const GlobalObject &GO) {
2296   // [n x [id, mdnode]]
2297   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2298   GO.getAllMetadata(MDs);
2299   for (const auto &I : MDs) {
2300     Record.push_back(I.first);
2301     Record.push_back(VE.getMetadataID(I.second));
2302   }
2303 }
2304 
2305 void ModuleBitcodeWriter::writeFunctionMetadataAttachment(const Function &F) {
2306   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
2307 
2308   SmallVector<uint64_t, 64> Record;
2309 
2310   if (F.hasMetadata()) {
2311     pushGlobalMetadataAttachment(Record, F);
2312     Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2313     Record.clear();
2314   }
2315 
2316   // Write metadata attachments
2317   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
2318   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2319   for (const BasicBlock &BB : F)
2320     for (const Instruction &I : BB) {
2321       MDs.clear();
2322       I.getAllMetadataOtherThanDebugLoc(MDs);
2323 
2324       // If no metadata, ignore instruction.
2325       if (MDs.empty()) continue;
2326 
2327       Record.push_back(VE.getInstructionID(&I));
2328 
2329       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
2330         Record.push_back(MDs[i].first);
2331         Record.push_back(VE.getMetadataID(MDs[i].second));
2332       }
2333       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2334       Record.clear();
2335     }
2336 
2337   Stream.ExitBlock();
2338 }
2339 
2340 void ModuleBitcodeWriter::writeModuleMetadataKinds() {
2341   SmallVector<uint64_t, 64> Record;
2342 
2343   // Write metadata kinds
2344   // METADATA_KIND - [n x [id, name]]
2345   SmallVector<StringRef, 8> Names;
2346   M.getMDKindNames(Names);
2347 
2348   if (Names.empty()) return;
2349 
2350   Stream.EnterSubblock(bitc::METADATA_KIND_BLOCK_ID, 3);
2351 
2352   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
2353     Record.push_back(MDKindID);
2354     StringRef KName = Names[MDKindID];
2355     Record.append(KName.begin(), KName.end());
2356 
2357     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
2358     Record.clear();
2359   }
2360 
2361   Stream.ExitBlock();
2362 }
2363 
2364 void ModuleBitcodeWriter::writeOperandBundleTags() {
2365   // Write metadata kinds
2366   //
2367   // OPERAND_BUNDLE_TAGS_BLOCK_ID : N x OPERAND_BUNDLE_TAG
2368   //
2369   // OPERAND_BUNDLE_TAG - [strchr x N]
2370 
2371   SmallVector<StringRef, 8> Tags;
2372   M.getOperandBundleTags(Tags);
2373 
2374   if (Tags.empty())
2375     return;
2376 
2377   Stream.EnterSubblock(bitc::OPERAND_BUNDLE_TAGS_BLOCK_ID, 3);
2378 
2379   SmallVector<uint64_t, 64> Record;
2380 
2381   for (auto Tag : Tags) {
2382     Record.append(Tag.begin(), Tag.end());
2383 
2384     Stream.EmitRecord(bitc::OPERAND_BUNDLE_TAG, Record, 0);
2385     Record.clear();
2386   }
2387 
2388   Stream.ExitBlock();
2389 }
2390 
2391 void ModuleBitcodeWriter::writeSyncScopeNames() {
2392   SmallVector<StringRef, 8> SSNs;
2393   M.getContext().getSyncScopeNames(SSNs);
2394   if (SSNs.empty())
2395     return;
2396 
2397   Stream.EnterSubblock(bitc::SYNC_SCOPE_NAMES_BLOCK_ID, 2);
2398 
2399   SmallVector<uint64_t, 64> Record;
2400   for (auto SSN : SSNs) {
2401     Record.append(SSN.begin(), SSN.end());
2402     Stream.EmitRecord(bitc::SYNC_SCOPE_NAME, Record, 0);
2403     Record.clear();
2404   }
2405 
2406   Stream.ExitBlock();
2407 }
2408 
2409 void ModuleBitcodeWriter::writeConstants(unsigned FirstVal, unsigned LastVal,
2410                                          bool isGlobal) {
2411   if (FirstVal == LastVal) return;
2412 
2413   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
2414 
2415   unsigned AggregateAbbrev = 0;
2416   unsigned String8Abbrev = 0;
2417   unsigned CString7Abbrev = 0;
2418   unsigned CString6Abbrev = 0;
2419   // If this is a constant pool for the module, emit module-specific abbrevs.
2420   if (isGlobal) {
2421     // Abbrev for CST_CODE_AGGREGATE.
2422     auto Abbv = std::make_shared<BitCodeAbbrev>();
2423     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
2424     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2425     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
2426     AggregateAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2427 
2428     // Abbrev for CST_CODE_STRING.
2429     Abbv = std::make_shared<BitCodeAbbrev>();
2430     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
2431     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2432     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2433     String8Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2434     // Abbrev for CST_CODE_CSTRING.
2435     Abbv = std::make_shared<BitCodeAbbrev>();
2436     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2437     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2438     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2439     CString7Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2440     // Abbrev for CST_CODE_CSTRING.
2441     Abbv = std::make_shared<BitCodeAbbrev>();
2442     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2443     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2444     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2445     CString6Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2446   }
2447 
2448   SmallVector<uint64_t, 64> Record;
2449 
2450   const ValueEnumerator::ValueList &Vals = VE.getValues();
2451   Type *LastTy = nullptr;
2452   for (unsigned i = FirstVal; i != LastVal; ++i) {
2453     const Value *V = Vals[i].first;
2454     // If we need to switch types, do so now.
2455     if (V->getType() != LastTy) {
2456       LastTy = V->getType();
2457       Record.push_back(VE.getTypeID(LastTy));
2458       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
2459                         CONSTANTS_SETTYPE_ABBREV);
2460       Record.clear();
2461     }
2462 
2463     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
2464       Record.push_back(
2465           unsigned(IA->hasSideEffects()) | unsigned(IA->isAlignStack()) << 1 |
2466           unsigned(IA->getDialect() & 1) << 2 | unsigned(IA->canThrow()) << 3);
2467 
2468       // Add the asm string.
2469       const std::string &AsmStr = IA->getAsmString();
2470       Record.push_back(AsmStr.size());
2471       Record.append(AsmStr.begin(), AsmStr.end());
2472 
2473       // Add the constraint string.
2474       const std::string &ConstraintStr = IA->getConstraintString();
2475       Record.push_back(ConstraintStr.size());
2476       Record.append(ConstraintStr.begin(), ConstraintStr.end());
2477       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
2478       Record.clear();
2479       continue;
2480     }
2481     const Constant *C = cast<Constant>(V);
2482     unsigned Code = -1U;
2483     unsigned AbbrevToUse = 0;
2484     if (C->isNullValue()) {
2485       Code = bitc::CST_CODE_NULL;
2486     } else if (isa<PoisonValue>(C)) {
2487       Code = bitc::CST_CODE_POISON;
2488     } else if (isa<UndefValue>(C)) {
2489       Code = bitc::CST_CODE_UNDEF;
2490     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
2491       if (IV->getBitWidth() <= 64) {
2492         uint64_t V = IV->getSExtValue();
2493         emitSignedInt64(Record, V);
2494         Code = bitc::CST_CODE_INTEGER;
2495         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
2496       } else {                             // Wide integers, > 64 bits in size.
2497         emitWideAPInt(Record, IV->getValue());
2498         Code = bitc::CST_CODE_WIDE_INTEGER;
2499       }
2500     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
2501       Code = bitc::CST_CODE_FLOAT;
2502       Type *Ty = CFP->getType();
2503       if (Ty->isHalfTy() || Ty->isBFloatTy() || Ty->isFloatTy() ||
2504           Ty->isDoubleTy()) {
2505         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
2506       } else if (Ty->isX86_FP80Ty()) {
2507         // api needed to prevent premature destruction
2508         // bits are not in the same order as a normal i80 APInt, compensate.
2509         APInt api = CFP->getValueAPF().bitcastToAPInt();
2510         const uint64_t *p = api.getRawData();
2511         Record.push_back((p[1] << 48) | (p[0] >> 16));
2512         Record.push_back(p[0] & 0xffffLL);
2513       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
2514         APInt api = CFP->getValueAPF().bitcastToAPInt();
2515         const uint64_t *p = api.getRawData();
2516         Record.push_back(p[0]);
2517         Record.push_back(p[1]);
2518       } else {
2519         assert(0 && "Unknown FP type!");
2520       }
2521     } else if (isa<ConstantDataSequential>(C) &&
2522                cast<ConstantDataSequential>(C)->isString()) {
2523       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
2524       // Emit constant strings specially.
2525       unsigned NumElts = Str->getNumElements();
2526       // If this is a null-terminated string, use the denser CSTRING encoding.
2527       if (Str->isCString()) {
2528         Code = bitc::CST_CODE_CSTRING;
2529         --NumElts;  // Don't encode the null, which isn't allowed by char6.
2530       } else {
2531         Code = bitc::CST_CODE_STRING;
2532         AbbrevToUse = String8Abbrev;
2533       }
2534       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
2535       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
2536       for (unsigned i = 0; i != NumElts; ++i) {
2537         unsigned char V = Str->getElementAsInteger(i);
2538         Record.push_back(V);
2539         isCStr7 &= (V & 128) == 0;
2540         if (isCStrChar6)
2541           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
2542       }
2543 
2544       if (isCStrChar6)
2545         AbbrevToUse = CString6Abbrev;
2546       else if (isCStr7)
2547         AbbrevToUse = CString7Abbrev;
2548     } else if (const ConstantDataSequential *CDS =
2549                   dyn_cast<ConstantDataSequential>(C)) {
2550       Code = bitc::CST_CODE_DATA;
2551       Type *EltTy = CDS->getElementType();
2552       if (isa<IntegerType>(EltTy)) {
2553         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2554           Record.push_back(CDS->getElementAsInteger(i));
2555       } else {
2556         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2557           Record.push_back(
2558               CDS->getElementAsAPFloat(i).bitcastToAPInt().getLimitedValue());
2559       }
2560     } else if (isa<ConstantAggregate>(C)) {
2561       Code = bitc::CST_CODE_AGGREGATE;
2562       for (const Value *Op : C->operands())
2563         Record.push_back(VE.getValueID(Op));
2564       AbbrevToUse = AggregateAbbrev;
2565     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
2566       switch (CE->getOpcode()) {
2567       default:
2568         if (Instruction::isCast(CE->getOpcode())) {
2569           Code = bitc::CST_CODE_CE_CAST;
2570           Record.push_back(getEncodedCastOpcode(CE->getOpcode()));
2571           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2572           Record.push_back(VE.getValueID(C->getOperand(0)));
2573           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
2574         } else {
2575           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
2576           Code = bitc::CST_CODE_CE_BINOP;
2577           Record.push_back(getEncodedBinaryOpcode(CE->getOpcode()));
2578           Record.push_back(VE.getValueID(C->getOperand(0)));
2579           Record.push_back(VE.getValueID(C->getOperand(1)));
2580           uint64_t Flags = getOptimizationFlags(CE);
2581           if (Flags != 0)
2582             Record.push_back(Flags);
2583         }
2584         break;
2585       case Instruction::FNeg: {
2586         assert(CE->getNumOperands() == 1 && "Unknown constant expr!");
2587         Code = bitc::CST_CODE_CE_UNOP;
2588         Record.push_back(getEncodedUnaryOpcode(CE->getOpcode()));
2589         Record.push_back(VE.getValueID(C->getOperand(0)));
2590         uint64_t Flags = getOptimizationFlags(CE);
2591         if (Flags != 0)
2592           Record.push_back(Flags);
2593         break;
2594       }
2595       case Instruction::GetElementPtr: {
2596         Code = bitc::CST_CODE_CE_GEP;
2597         const auto *GO = cast<GEPOperator>(C);
2598         Record.push_back(VE.getTypeID(GO->getSourceElementType()));
2599         if (Optional<unsigned> Idx = GO->getInRangeIndex()) {
2600           Code = bitc::CST_CODE_CE_GEP_WITH_INRANGE_INDEX;
2601           Record.push_back((*Idx << 1) | GO->isInBounds());
2602         } else if (GO->isInBounds())
2603           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
2604         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
2605           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
2606           Record.push_back(VE.getValueID(C->getOperand(i)));
2607         }
2608         break;
2609       }
2610       case Instruction::Select:
2611         Code = bitc::CST_CODE_CE_SELECT;
2612         Record.push_back(VE.getValueID(C->getOperand(0)));
2613         Record.push_back(VE.getValueID(C->getOperand(1)));
2614         Record.push_back(VE.getValueID(C->getOperand(2)));
2615         break;
2616       case Instruction::ExtractElement:
2617         Code = bitc::CST_CODE_CE_EXTRACTELT;
2618         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2619         Record.push_back(VE.getValueID(C->getOperand(0)));
2620         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
2621         Record.push_back(VE.getValueID(C->getOperand(1)));
2622         break;
2623       case Instruction::InsertElement:
2624         Code = bitc::CST_CODE_CE_INSERTELT;
2625         Record.push_back(VE.getValueID(C->getOperand(0)));
2626         Record.push_back(VE.getValueID(C->getOperand(1)));
2627         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
2628         Record.push_back(VE.getValueID(C->getOperand(2)));
2629         break;
2630       case Instruction::ShuffleVector:
2631         // If the return type and argument types are the same, this is a
2632         // standard shufflevector instruction.  If the types are different,
2633         // then the shuffle is widening or truncating the input vectors, and
2634         // the argument type must also be encoded.
2635         if (C->getType() == C->getOperand(0)->getType()) {
2636           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
2637         } else {
2638           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
2639           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2640         }
2641         Record.push_back(VE.getValueID(C->getOperand(0)));
2642         Record.push_back(VE.getValueID(C->getOperand(1)));
2643         Record.push_back(VE.getValueID(CE->getShuffleMaskForBitcode()));
2644         break;
2645       case Instruction::ICmp:
2646       case Instruction::FCmp:
2647         Code = bitc::CST_CODE_CE_CMP;
2648         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2649         Record.push_back(VE.getValueID(C->getOperand(0)));
2650         Record.push_back(VE.getValueID(C->getOperand(1)));
2651         Record.push_back(CE->getPredicate());
2652         break;
2653       }
2654     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
2655       Code = bitc::CST_CODE_BLOCKADDRESS;
2656       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
2657       Record.push_back(VE.getValueID(BA->getFunction()));
2658       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
2659     } else if (const auto *Equiv = dyn_cast<DSOLocalEquivalent>(C)) {
2660       Code = bitc::CST_CODE_DSO_LOCAL_EQUIVALENT;
2661       Record.push_back(VE.getTypeID(Equiv->getGlobalValue()->getType()));
2662       Record.push_back(VE.getValueID(Equiv->getGlobalValue()));
2663     } else {
2664 #ifndef NDEBUG
2665       C->dump();
2666 #endif
2667       llvm_unreachable("Unknown constant!");
2668     }
2669     Stream.EmitRecord(Code, Record, AbbrevToUse);
2670     Record.clear();
2671   }
2672 
2673   Stream.ExitBlock();
2674 }
2675 
2676 void ModuleBitcodeWriter::writeModuleConstants() {
2677   const ValueEnumerator::ValueList &Vals = VE.getValues();
2678 
2679   // Find the first constant to emit, which is the first non-globalvalue value.
2680   // We know globalvalues have been emitted by WriteModuleInfo.
2681   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
2682     if (!isa<GlobalValue>(Vals[i].first)) {
2683       writeConstants(i, Vals.size(), true);
2684       return;
2685     }
2686   }
2687 }
2688 
2689 /// pushValueAndType - The file has to encode both the value and type id for
2690 /// many values, because we need to know what type to create for forward
2691 /// references.  However, most operands are not forward references, so this type
2692 /// field is not needed.
2693 ///
2694 /// This function adds V's value ID to Vals.  If the value ID is higher than the
2695 /// instruction ID, then it is a forward reference, and it also includes the
2696 /// type ID.  The value ID that is written is encoded relative to the InstID.
2697 bool ModuleBitcodeWriter::pushValueAndType(const Value *V, unsigned InstID,
2698                                            SmallVectorImpl<unsigned> &Vals) {
2699   unsigned ValID = VE.getValueID(V);
2700   // Make encoding relative to the InstID.
2701   Vals.push_back(InstID - ValID);
2702   if (ValID >= InstID) {
2703     Vals.push_back(VE.getTypeID(V->getType()));
2704     return true;
2705   }
2706   return false;
2707 }
2708 
2709 void ModuleBitcodeWriter::writeOperandBundles(const CallBase &CS,
2710                                               unsigned InstID) {
2711   SmallVector<unsigned, 64> Record;
2712   LLVMContext &C = CS.getContext();
2713 
2714   for (unsigned i = 0, e = CS.getNumOperandBundles(); i != e; ++i) {
2715     const auto &Bundle = CS.getOperandBundleAt(i);
2716     Record.push_back(C.getOperandBundleTagID(Bundle.getTagName()));
2717 
2718     for (auto &Input : Bundle.Inputs)
2719       pushValueAndType(Input, InstID, Record);
2720 
2721     Stream.EmitRecord(bitc::FUNC_CODE_OPERAND_BUNDLE, Record);
2722     Record.clear();
2723   }
2724 }
2725 
2726 /// pushValue - Like pushValueAndType, but where the type of the value is
2727 /// omitted (perhaps it was already encoded in an earlier operand).
2728 void ModuleBitcodeWriter::pushValue(const Value *V, unsigned InstID,
2729                                     SmallVectorImpl<unsigned> &Vals) {
2730   unsigned ValID = VE.getValueID(V);
2731   Vals.push_back(InstID - ValID);
2732 }
2733 
2734 void ModuleBitcodeWriter::pushValueSigned(const Value *V, unsigned InstID,
2735                                           SmallVectorImpl<uint64_t> &Vals) {
2736   unsigned ValID = VE.getValueID(V);
2737   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
2738   emitSignedInt64(Vals, diff);
2739 }
2740 
2741 /// WriteInstruction - Emit an instruction to the specified stream.
2742 void ModuleBitcodeWriter::writeInstruction(const Instruction &I,
2743                                            unsigned InstID,
2744                                            SmallVectorImpl<unsigned> &Vals) {
2745   unsigned Code = 0;
2746   unsigned AbbrevToUse = 0;
2747   VE.setInstructionID(&I);
2748   switch (I.getOpcode()) {
2749   default:
2750     if (Instruction::isCast(I.getOpcode())) {
2751       Code = bitc::FUNC_CODE_INST_CAST;
2752       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2753         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
2754       Vals.push_back(VE.getTypeID(I.getType()));
2755       Vals.push_back(getEncodedCastOpcode(I.getOpcode()));
2756     } else {
2757       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
2758       Code = bitc::FUNC_CODE_INST_BINOP;
2759       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2760         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
2761       pushValue(I.getOperand(1), InstID, Vals);
2762       Vals.push_back(getEncodedBinaryOpcode(I.getOpcode()));
2763       uint64_t Flags = getOptimizationFlags(&I);
2764       if (Flags != 0) {
2765         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
2766           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
2767         Vals.push_back(Flags);
2768       }
2769     }
2770     break;
2771   case Instruction::FNeg: {
2772     Code = bitc::FUNC_CODE_INST_UNOP;
2773     if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2774       AbbrevToUse = FUNCTION_INST_UNOP_ABBREV;
2775     Vals.push_back(getEncodedUnaryOpcode(I.getOpcode()));
2776     uint64_t Flags = getOptimizationFlags(&I);
2777     if (Flags != 0) {
2778       if (AbbrevToUse == FUNCTION_INST_UNOP_ABBREV)
2779         AbbrevToUse = FUNCTION_INST_UNOP_FLAGS_ABBREV;
2780       Vals.push_back(Flags);
2781     }
2782     break;
2783   }
2784   case Instruction::GetElementPtr: {
2785     Code = bitc::FUNC_CODE_INST_GEP;
2786     AbbrevToUse = FUNCTION_INST_GEP_ABBREV;
2787     auto &GEPInst = cast<GetElementPtrInst>(I);
2788     Vals.push_back(GEPInst.isInBounds());
2789     Vals.push_back(VE.getTypeID(GEPInst.getSourceElementType()));
2790     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
2791       pushValueAndType(I.getOperand(i), InstID, Vals);
2792     break;
2793   }
2794   case Instruction::ExtractValue: {
2795     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
2796     pushValueAndType(I.getOperand(0), InstID, Vals);
2797     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
2798     Vals.append(EVI->idx_begin(), EVI->idx_end());
2799     break;
2800   }
2801   case Instruction::InsertValue: {
2802     Code = bitc::FUNC_CODE_INST_INSERTVAL;
2803     pushValueAndType(I.getOperand(0), InstID, Vals);
2804     pushValueAndType(I.getOperand(1), InstID, Vals);
2805     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
2806     Vals.append(IVI->idx_begin(), IVI->idx_end());
2807     break;
2808   }
2809   case Instruction::Select: {
2810     Code = bitc::FUNC_CODE_INST_VSELECT;
2811     pushValueAndType(I.getOperand(1), InstID, Vals);
2812     pushValue(I.getOperand(2), InstID, Vals);
2813     pushValueAndType(I.getOperand(0), InstID, Vals);
2814     uint64_t Flags = getOptimizationFlags(&I);
2815     if (Flags != 0)
2816       Vals.push_back(Flags);
2817     break;
2818   }
2819   case Instruction::ExtractElement:
2820     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
2821     pushValueAndType(I.getOperand(0), InstID, Vals);
2822     pushValueAndType(I.getOperand(1), InstID, Vals);
2823     break;
2824   case Instruction::InsertElement:
2825     Code = bitc::FUNC_CODE_INST_INSERTELT;
2826     pushValueAndType(I.getOperand(0), InstID, Vals);
2827     pushValue(I.getOperand(1), InstID, Vals);
2828     pushValueAndType(I.getOperand(2), InstID, Vals);
2829     break;
2830   case Instruction::ShuffleVector:
2831     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
2832     pushValueAndType(I.getOperand(0), InstID, Vals);
2833     pushValue(I.getOperand(1), InstID, Vals);
2834     pushValue(cast<ShuffleVectorInst>(I).getShuffleMaskForBitcode(), InstID,
2835               Vals);
2836     break;
2837   case Instruction::ICmp:
2838   case Instruction::FCmp: {
2839     // compare returning Int1Ty or vector of Int1Ty
2840     Code = bitc::FUNC_CODE_INST_CMP2;
2841     pushValueAndType(I.getOperand(0), InstID, Vals);
2842     pushValue(I.getOperand(1), InstID, Vals);
2843     Vals.push_back(cast<CmpInst>(I).getPredicate());
2844     uint64_t Flags = getOptimizationFlags(&I);
2845     if (Flags != 0)
2846       Vals.push_back(Flags);
2847     break;
2848   }
2849 
2850   case Instruction::Ret:
2851     {
2852       Code = bitc::FUNC_CODE_INST_RET;
2853       unsigned NumOperands = I.getNumOperands();
2854       if (NumOperands == 0)
2855         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
2856       else if (NumOperands == 1) {
2857         if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2858           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
2859       } else {
2860         for (unsigned i = 0, e = NumOperands; i != e; ++i)
2861           pushValueAndType(I.getOperand(i), InstID, Vals);
2862       }
2863     }
2864     break;
2865   case Instruction::Br:
2866     {
2867       Code = bitc::FUNC_CODE_INST_BR;
2868       const BranchInst &II = cast<BranchInst>(I);
2869       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
2870       if (II.isConditional()) {
2871         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
2872         pushValue(II.getCondition(), InstID, Vals);
2873       }
2874     }
2875     break;
2876   case Instruction::Switch:
2877     {
2878       Code = bitc::FUNC_CODE_INST_SWITCH;
2879       const SwitchInst &SI = cast<SwitchInst>(I);
2880       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
2881       pushValue(SI.getCondition(), InstID, Vals);
2882       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
2883       for (auto Case : SI.cases()) {
2884         Vals.push_back(VE.getValueID(Case.getCaseValue()));
2885         Vals.push_back(VE.getValueID(Case.getCaseSuccessor()));
2886       }
2887     }
2888     break;
2889   case Instruction::IndirectBr:
2890     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
2891     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2892     // Encode the address operand as relative, but not the basic blocks.
2893     pushValue(I.getOperand(0), InstID, Vals);
2894     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
2895       Vals.push_back(VE.getValueID(I.getOperand(i)));
2896     break;
2897 
2898   case Instruction::Invoke: {
2899     const InvokeInst *II = cast<InvokeInst>(&I);
2900     const Value *Callee = II->getCalledOperand();
2901     FunctionType *FTy = II->getFunctionType();
2902 
2903     if (II->hasOperandBundles())
2904       writeOperandBundles(*II, InstID);
2905 
2906     Code = bitc::FUNC_CODE_INST_INVOKE;
2907 
2908     Vals.push_back(VE.getAttributeListID(II->getAttributes()));
2909     Vals.push_back(II->getCallingConv() | 1 << 13);
2910     Vals.push_back(VE.getValueID(II->getNormalDest()));
2911     Vals.push_back(VE.getValueID(II->getUnwindDest()));
2912     Vals.push_back(VE.getTypeID(FTy));
2913     pushValueAndType(Callee, InstID, Vals);
2914 
2915     // Emit value #'s for the fixed parameters.
2916     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
2917       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
2918 
2919     // Emit type/value pairs for varargs params.
2920     if (FTy->isVarArg()) {
2921       for (unsigned i = FTy->getNumParams(), e = II->getNumArgOperands();
2922            i != e; ++i)
2923         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
2924     }
2925     break;
2926   }
2927   case Instruction::Resume:
2928     Code = bitc::FUNC_CODE_INST_RESUME;
2929     pushValueAndType(I.getOperand(0), InstID, Vals);
2930     break;
2931   case Instruction::CleanupRet: {
2932     Code = bitc::FUNC_CODE_INST_CLEANUPRET;
2933     const auto &CRI = cast<CleanupReturnInst>(I);
2934     pushValue(CRI.getCleanupPad(), InstID, Vals);
2935     if (CRI.hasUnwindDest())
2936       Vals.push_back(VE.getValueID(CRI.getUnwindDest()));
2937     break;
2938   }
2939   case Instruction::CatchRet: {
2940     Code = bitc::FUNC_CODE_INST_CATCHRET;
2941     const auto &CRI = cast<CatchReturnInst>(I);
2942     pushValue(CRI.getCatchPad(), InstID, Vals);
2943     Vals.push_back(VE.getValueID(CRI.getSuccessor()));
2944     break;
2945   }
2946   case Instruction::CleanupPad:
2947   case Instruction::CatchPad: {
2948     const auto &FuncletPad = cast<FuncletPadInst>(I);
2949     Code = isa<CatchPadInst>(FuncletPad) ? bitc::FUNC_CODE_INST_CATCHPAD
2950                                          : bitc::FUNC_CODE_INST_CLEANUPPAD;
2951     pushValue(FuncletPad.getParentPad(), InstID, Vals);
2952 
2953     unsigned NumArgOperands = FuncletPad.getNumArgOperands();
2954     Vals.push_back(NumArgOperands);
2955     for (unsigned Op = 0; Op != NumArgOperands; ++Op)
2956       pushValueAndType(FuncletPad.getArgOperand(Op), InstID, Vals);
2957     break;
2958   }
2959   case Instruction::CatchSwitch: {
2960     Code = bitc::FUNC_CODE_INST_CATCHSWITCH;
2961     const auto &CatchSwitch = cast<CatchSwitchInst>(I);
2962 
2963     pushValue(CatchSwitch.getParentPad(), InstID, Vals);
2964 
2965     unsigned NumHandlers = CatchSwitch.getNumHandlers();
2966     Vals.push_back(NumHandlers);
2967     for (const BasicBlock *CatchPadBB : CatchSwitch.handlers())
2968       Vals.push_back(VE.getValueID(CatchPadBB));
2969 
2970     if (CatchSwitch.hasUnwindDest())
2971       Vals.push_back(VE.getValueID(CatchSwitch.getUnwindDest()));
2972     break;
2973   }
2974   case Instruction::CallBr: {
2975     const CallBrInst *CBI = cast<CallBrInst>(&I);
2976     const Value *Callee = CBI->getCalledOperand();
2977     FunctionType *FTy = CBI->getFunctionType();
2978 
2979     if (CBI->hasOperandBundles())
2980       writeOperandBundles(*CBI, InstID);
2981 
2982     Code = bitc::FUNC_CODE_INST_CALLBR;
2983 
2984     Vals.push_back(VE.getAttributeListID(CBI->getAttributes()));
2985 
2986     Vals.push_back(CBI->getCallingConv() << bitc::CALL_CCONV |
2987                    1 << bitc::CALL_EXPLICIT_TYPE);
2988 
2989     Vals.push_back(VE.getValueID(CBI->getDefaultDest()));
2990     Vals.push_back(CBI->getNumIndirectDests());
2991     for (unsigned i = 0, e = CBI->getNumIndirectDests(); i != e; ++i)
2992       Vals.push_back(VE.getValueID(CBI->getIndirectDest(i)));
2993 
2994     Vals.push_back(VE.getTypeID(FTy));
2995     pushValueAndType(Callee, InstID, Vals);
2996 
2997     // Emit value #'s for the fixed parameters.
2998     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
2999       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
3000 
3001     // Emit type/value pairs for varargs params.
3002     if (FTy->isVarArg()) {
3003       for (unsigned i = FTy->getNumParams(), e = CBI->getNumArgOperands();
3004            i != e; ++i)
3005         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
3006     }
3007     break;
3008   }
3009   case Instruction::Unreachable:
3010     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
3011     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
3012     break;
3013 
3014   case Instruction::PHI: {
3015     const PHINode &PN = cast<PHINode>(I);
3016     Code = bitc::FUNC_CODE_INST_PHI;
3017     // With the newer instruction encoding, forward references could give
3018     // negative valued IDs.  This is most common for PHIs, so we use
3019     // signed VBRs.
3020     SmallVector<uint64_t, 128> Vals64;
3021     Vals64.push_back(VE.getTypeID(PN.getType()));
3022     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
3023       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64);
3024       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
3025     }
3026 
3027     uint64_t Flags = getOptimizationFlags(&I);
3028     if (Flags != 0)
3029       Vals64.push_back(Flags);
3030 
3031     // Emit a Vals64 vector and exit.
3032     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
3033     Vals64.clear();
3034     return;
3035   }
3036 
3037   case Instruction::LandingPad: {
3038     const LandingPadInst &LP = cast<LandingPadInst>(I);
3039     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
3040     Vals.push_back(VE.getTypeID(LP.getType()));
3041     Vals.push_back(LP.isCleanup());
3042     Vals.push_back(LP.getNumClauses());
3043     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
3044       if (LP.isCatch(I))
3045         Vals.push_back(LandingPadInst::Catch);
3046       else
3047         Vals.push_back(LandingPadInst::Filter);
3048       pushValueAndType(LP.getClause(I), InstID, Vals);
3049     }
3050     break;
3051   }
3052 
3053   case Instruction::Alloca: {
3054     Code = bitc::FUNC_CODE_INST_ALLOCA;
3055     const AllocaInst &AI = cast<AllocaInst>(I);
3056     Vals.push_back(VE.getTypeID(AI.getAllocatedType()));
3057     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
3058     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
3059     using APV = AllocaPackedValues;
3060     unsigned Record = 0;
3061     Bitfield::set<APV::Align>(Record, getEncodedAlign(AI.getAlign()));
3062     Bitfield::set<APV::UsedWithInAlloca>(Record, AI.isUsedWithInAlloca());
3063     Bitfield::set<APV::ExplicitType>(Record, true);
3064     Bitfield::set<APV::SwiftError>(Record, AI.isSwiftError());
3065     Vals.push_back(Record);
3066     break;
3067   }
3068 
3069   case Instruction::Load:
3070     if (cast<LoadInst>(I).isAtomic()) {
3071       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
3072       pushValueAndType(I.getOperand(0), InstID, Vals);
3073     } else {
3074       Code = bitc::FUNC_CODE_INST_LOAD;
3075       if (!pushValueAndType(I.getOperand(0), InstID, Vals)) // ptr
3076         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
3077     }
3078     Vals.push_back(VE.getTypeID(I.getType()));
3079     Vals.push_back(getEncodedAlign(cast<LoadInst>(I).getAlign()));
3080     Vals.push_back(cast<LoadInst>(I).isVolatile());
3081     if (cast<LoadInst>(I).isAtomic()) {
3082       Vals.push_back(getEncodedOrdering(cast<LoadInst>(I).getOrdering()));
3083       Vals.push_back(getEncodedSyncScopeID(cast<LoadInst>(I).getSyncScopeID()));
3084     }
3085     break;
3086   case Instruction::Store:
3087     if (cast<StoreInst>(I).isAtomic())
3088       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
3089     else
3090       Code = bitc::FUNC_CODE_INST_STORE;
3091     pushValueAndType(I.getOperand(1), InstID, Vals); // ptrty + ptr
3092     pushValueAndType(I.getOperand(0), InstID, Vals); // valty + val
3093     Vals.push_back(getEncodedAlign(cast<StoreInst>(I).getAlign()));
3094     Vals.push_back(cast<StoreInst>(I).isVolatile());
3095     if (cast<StoreInst>(I).isAtomic()) {
3096       Vals.push_back(getEncodedOrdering(cast<StoreInst>(I).getOrdering()));
3097       Vals.push_back(
3098           getEncodedSyncScopeID(cast<StoreInst>(I).getSyncScopeID()));
3099     }
3100     break;
3101   case Instruction::AtomicCmpXchg:
3102     Code = bitc::FUNC_CODE_INST_CMPXCHG;
3103     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
3104     pushValueAndType(I.getOperand(1), InstID, Vals); // cmp.
3105     pushValue(I.getOperand(2), InstID, Vals);        // newval.
3106     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
3107     Vals.push_back(
3108         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
3109     Vals.push_back(
3110         getEncodedSyncScopeID(cast<AtomicCmpXchgInst>(I).getSyncScopeID()));
3111     Vals.push_back(
3112         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
3113     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
3114     Vals.push_back(getEncodedAlign(cast<AtomicCmpXchgInst>(I).getAlign()));
3115     break;
3116   case Instruction::AtomicRMW:
3117     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
3118     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
3119     pushValueAndType(I.getOperand(1), InstID, Vals); // valty + val
3120     Vals.push_back(
3121         getEncodedRMWOperation(cast<AtomicRMWInst>(I).getOperation()));
3122     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
3123     Vals.push_back(getEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
3124     Vals.push_back(
3125         getEncodedSyncScopeID(cast<AtomicRMWInst>(I).getSyncScopeID()));
3126     Vals.push_back(getEncodedAlign(cast<AtomicRMWInst>(I).getAlign()));
3127     break;
3128   case Instruction::Fence:
3129     Code = bitc::FUNC_CODE_INST_FENCE;
3130     Vals.push_back(getEncodedOrdering(cast<FenceInst>(I).getOrdering()));
3131     Vals.push_back(getEncodedSyncScopeID(cast<FenceInst>(I).getSyncScopeID()));
3132     break;
3133   case Instruction::Call: {
3134     const CallInst &CI = cast<CallInst>(I);
3135     FunctionType *FTy = CI.getFunctionType();
3136 
3137     if (CI.hasOperandBundles())
3138       writeOperandBundles(CI, InstID);
3139 
3140     Code = bitc::FUNC_CODE_INST_CALL;
3141 
3142     Vals.push_back(VE.getAttributeListID(CI.getAttributes()));
3143 
3144     unsigned Flags = getOptimizationFlags(&I);
3145     Vals.push_back(CI.getCallingConv() << bitc::CALL_CCONV |
3146                    unsigned(CI.isTailCall()) << bitc::CALL_TAIL |
3147                    unsigned(CI.isMustTailCall()) << bitc::CALL_MUSTTAIL |
3148                    1 << bitc::CALL_EXPLICIT_TYPE |
3149                    unsigned(CI.isNoTailCall()) << bitc::CALL_NOTAIL |
3150                    unsigned(Flags != 0) << bitc::CALL_FMF);
3151     if (Flags != 0)
3152       Vals.push_back(Flags);
3153 
3154     Vals.push_back(VE.getTypeID(FTy));
3155     pushValueAndType(CI.getCalledOperand(), InstID, Vals); // Callee
3156 
3157     // Emit value #'s for the fixed parameters.
3158     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
3159       // Check for labels (can happen with asm labels).
3160       if (FTy->getParamType(i)->isLabelTy())
3161         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
3162       else
3163         pushValue(CI.getArgOperand(i), InstID, Vals); // fixed param.
3164     }
3165 
3166     // Emit type/value pairs for varargs params.
3167     if (FTy->isVarArg()) {
3168       for (unsigned i = FTy->getNumParams(), e = CI.getNumArgOperands();
3169            i != e; ++i)
3170         pushValueAndType(CI.getArgOperand(i), InstID, Vals); // varargs
3171     }
3172     break;
3173   }
3174   case Instruction::VAArg:
3175     Code = bitc::FUNC_CODE_INST_VAARG;
3176     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
3177     pushValue(I.getOperand(0), InstID, Vals);                   // valist.
3178     Vals.push_back(VE.getTypeID(I.getType())); // restype.
3179     break;
3180   case Instruction::Freeze:
3181     Code = bitc::FUNC_CODE_INST_FREEZE;
3182     pushValueAndType(I.getOperand(0), InstID, Vals);
3183     break;
3184   }
3185 
3186   Stream.EmitRecord(Code, Vals, AbbrevToUse);
3187   Vals.clear();
3188 }
3189 
3190 /// Write a GlobalValue VST to the module. The purpose of this data structure is
3191 /// to allow clients to efficiently find the function body.
3192 void ModuleBitcodeWriter::writeGlobalValueSymbolTable(
3193   DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3194   // Get the offset of the VST we are writing, and backpatch it into
3195   // the VST forward declaration record.
3196   uint64_t VSTOffset = Stream.GetCurrentBitNo();
3197   // The BitcodeStartBit was the stream offset of the identification block.
3198   VSTOffset -= bitcodeStartBit();
3199   assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
3200   // Note that we add 1 here because the offset is relative to one word
3201   // before the start of the identification block, which was historically
3202   // always the start of the regular bitcode header.
3203   Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32 + 1);
3204 
3205   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3206 
3207   auto Abbv = std::make_shared<BitCodeAbbrev>();
3208   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
3209   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
3210   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
3211   unsigned FnEntryAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3212 
3213   for (const Function &F : M) {
3214     uint64_t Record[2];
3215 
3216     if (F.isDeclaration())
3217       continue;
3218 
3219     Record[0] = VE.getValueID(&F);
3220 
3221     // Save the word offset of the function (from the start of the
3222     // actual bitcode written to the stream).
3223     uint64_t BitcodeIndex = FunctionToBitcodeIndex[&F] - bitcodeStartBit();
3224     assert((BitcodeIndex & 31) == 0 && "function block not 32-bit aligned");
3225     // Note that we add 1 here because the offset is relative to one word
3226     // before the start of the identification block, which was historically
3227     // always the start of the regular bitcode header.
3228     Record[1] = BitcodeIndex / 32 + 1;
3229 
3230     Stream.EmitRecord(bitc::VST_CODE_FNENTRY, Record, FnEntryAbbrev);
3231   }
3232 
3233   Stream.ExitBlock();
3234 }
3235 
3236 /// Emit names for arguments, instructions and basic blocks in a function.
3237 void ModuleBitcodeWriter::writeFunctionLevelValueSymbolTable(
3238     const ValueSymbolTable &VST) {
3239   if (VST.empty())
3240     return;
3241 
3242   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3243 
3244   // FIXME: Set up the abbrev, we know how many values there are!
3245   // FIXME: We know if the type names can use 7-bit ascii.
3246   SmallVector<uint64_t, 64> NameVals;
3247 
3248   for (const ValueName &Name : VST) {
3249     // Figure out the encoding to use for the name.
3250     StringEncoding Bits = getStringEncoding(Name.getKey());
3251 
3252     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
3253     NameVals.push_back(VE.getValueID(Name.getValue()));
3254 
3255     // VST_CODE_ENTRY:   [valueid, namechar x N]
3256     // VST_CODE_BBENTRY: [bbid, namechar x N]
3257     unsigned Code;
3258     if (isa<BasicBlock>(Name.getValue())) {
3259       Code = bitc::VST_CODE_BBENTRY;
3260       if (Bits == SE_Char6)
3261         AbbrevToUse = VST_BBENTRY_6_ABBREV;
3262     } else {
3263       Code = bitc::VST_CODE_ENTRY;
3264       if (Bits == SE_Char6)
3265         AbbrevToUse = VST_ENTRY_6_ABBREV;
3266       else if (Bits == SE_Fixed7)
3267         AbbrevToUse = VST_ENTRY_7_ABBREV;
3268     }
3269 
3270     for (const auto P : Name.getKey())
3271       NameVals.push_back((unsigned char)P);
3272 
3273     // Emit the finished record.
3274     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
3275     NameVals.clear();
3276   }
3277 
3278   Stream.ExitBlock();
3279 }
3280 
3281 void ModuleBitcodeWriter::writeUseList(UseListOrder &&Order) {
3282   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
3283   unsigned Code;
3284   if (isa<BasicBlock>(Order.V))
3285     Code = bitc::USELIST_CODE_BB;
3286   else
3287     Code = bitc::USELIST_CODE_DEFAULT;
3288 
3289   SmallVector<uint64_t, 64> Record(Order.Shuffle.begin(), Order.Shuffle.end());
3290   Record.push_back(VE.getValueID(Order.V));
3291   Stream.EmitRecord(Code, Record);
3292 }
3293 
3294 void ModuleBitcodeWriter::writeUseListBlock(const Function *F) {
3295   assert(VE.shouldPreserveUseListOrder() &&
3296          "Expected to be preserving use-list order");
3297 
3298   auto hasMore = [&]() {
3299     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
3300   };
3301   if (!hasMore())
3302     // Nothing to do.
3303     return;
3304 
3305   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
3306   while (hasMore()) {
3307     writeUseList(std::move(VE.UseListOrders.back()));
3308     VE.UseListOrders.pop_back();
3309   }
3310   Stream.ExitBlock();
3311 }
3312 
3313 /// Emit a function body to the module stream.
3314 void ModuleBitcodeWriter::writeFunction(
3315     const Function &F,
3316     DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3317   // Save the bitcode index of the start of this function block for recording
3318   // in the VST.
3319   FunctionToBitcodeIndex[&F] = Stream.GetCurrentBitNo();
3320 
3321   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
3322   VE.incorporateFunction(F);
3323 
3324   SmallVector<unsigned, 64> Vals;
3325 
3326   // Emit the number of basic blocks, so the reader can create them ahead of
3327   // time.
3328   Vals.push_back(VE.getBasicBlocks().size());
3329   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
3330   Vals.clear();
3331 
3332   // If there are function-local constants, emit them now.
3333   unsigned CstStart, CstEnd;
3334   VE.getFunctionConstantRange(CstStart, CstEnd);
3335   writeConstants(CstStart, CstEnd, false);
3336 
3337   // If there is function-local metadata, emit it now.
3338   writeFunctionMetadata(F);
3339 
3340   // Keep a running idea of what the instruction ID is.
3341   unsigned InstID = CstEnd;
3342 
3343   bool NeedsMetadataAttachment = F.hasMetadata();
3344 
3345   DILocation *LastDL = nullptr;
3346   // Finally, emit all the instructions, in order.
3347   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
3348     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
3349          I != E; ++I) {
3350       writeInstruction(*I, InstID, Vals);
3351 
3352       if (!I->getType()->isVoidTy())
3353         ++InstID;
3354 
3355       // If the instruction has metadata, write a metadata attachment later.
3356       NeedsMetadataAttachment |= I->hasMetadataOtherThanDebugLoc();
3357 
3358       // If the instruction has a debug location, emit it.
3359       DILocation *DL = I->getDebugLoc();
3360       if (!DL)
3361         continue;
3362 
3363       if (DL == LastDL) {
3364         // Just repeat the same debug loc as last time.
3365         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
3366         continue;
3367       }
3368 
3369       Vals.push_back(DL->getLine());
3370       Vals.push_back(DL->getColumn());
3371       Vals.push_back(VE.getMetadataOrNullID(DL->getScope()));
3372       Vals.push_back(VE.getMetadataOrNullID(DL->getInlinedAt()));
3373       Vals.push_back(DL->isImplicitCode());
3374       Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
3375       Vals.clear();
3376 
3377       LastDL = DL;
3378     }
3379 
3380   // Emit names for all the instructions etc.
3381   if (auto *Symtab = F.getValueSymbolTable())
3382     writeFunctionLevelValueSymbolTable(*Symtab);
3383 
3384   if (NeedsMetadataAttachment)
3385     writeFunctionMetadataAttachment(F);
3386   if (VE.shouldPreserveUseListOrder())
3387     writeUseListBlock(&F);
3388   VE.purgeFunction();
3389   Stream.ExitBlock();
3390 }
3391 
3392 // Emit blockinfo, which defines the standard abbreviations etc.
3393 void ModuleBitcodeWriter::writeBlockInfo() {
3394   // We only want to emit block info records for blocks that have multiple
3395   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
3396   // Other blocks can define their abbrevs inline.
3397   Stream.EnterBlockInfoBlock();
3398 
3399   { // 8-bit fixed-width VST_CODE_ENTRY/VST_CODE_BBENTRY strings.
3400     auto Abbv = std::make_shared<BitCodeAbbrev>();
3401     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
3402     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3403     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3404     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3405     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3406         VST_ENTRY_8_ABBREV)
3407       llvm_unreachable("Unexpected abbrev ordering!");
3408   }
3409 
3410   { // 7-bit fixed width VST_CODE_ENTRY strings.
3411     auto Abbv = std::make_shared<BitCodeAbbrev>();
3412     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3413     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3414     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3415     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3416     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3417         VST_ENTRY_7_ABBREV)
3418       llvm_unreachable("Unexpected abbrev ordering!");
3419   }
3420   { // 6-bit char6 VST_CODE_ENTRY strings.
3421     auto Abbv = std::make_shared<BitCodeAbbrev>();
3422     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3423     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3424     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3425     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3426     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3427         VST_ENTRY_6_ABBREV)
3428       llvm_unreachable("Unexpected abbrev ordering!");
3429   }
3430   { // 6-bit char6 VST_CODE_BBENTRY strings.
3431     auto Abbv = std::make_shared<BitCodeAbbrev>();
3432     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
3433     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3434     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3435     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3436     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3437         VST_BBENTRY_6_ABBREV)
3438       llvm_unreachable("Unexpected abbrev ordering!");
3439   }
3440 
3441   { // SETTYPE abbrev for CONSTANTS_BLOCK.
3442     auto Abbv = std::make_shared<BitCodeAbbrev>();
3443     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
3444     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
3445                               VE.computeBitsRequiredForTypeIndicies()));
3446     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3447         CONSTANTS_SETTYPE_ABBREV)
3448       llvm_unreachable("Unexpected abbrev ordering!");
3449   }
3450 
3451   { // INTEGER abbrev for CONSTANTS_BLOCK.
3452     auto Abbv = std::make_shared<BitCodeAbbrev>();
3453     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
3454     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3455     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3456         CONSTANTS_INTEGER_ABBREV)
3457       llvm_unreachable("Unexpected abbrev ordering!");
3458   }
3459 
3460   { // CE_CAST abbrev for CONSTANTS_BLOCK.
3461     auto Abbv = std::make_shared<BitCodeAbbrev>();
3462     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
3463     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
3464     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
3465                               VE.computeBitsRequiredForTypeIndicies()));
3466     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
3467 
3468     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3469         CONSTANTS_CE_CAST_Abbrev)
3470       llvm_unreachable("Unexpected abbrev ordering!");
3471   }
3472   { // NULL abbrev for CONSTANTS_BLOCK.
3473     auto Abbv = std::make_shared<BitCodeAbbrev>();
3474     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
3475     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3476         CONSTANTS_NULL_Abbrev)
3477       llvm_unreachable("Unexpected abbrev ordering!");
3478   }
3479 
3480   // FIXME: This should only use space for first class types!
3481 
3482   { // INST_LOAD abbrev for FUNCTION_BLOCK.
3483     auto Abbv = std::make_shared<BitCodeAbbrev>();
3484     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
3485     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
3486     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
3487                               VE.computeBitsRequiredForTypeIndicies()));
3488     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
3489     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
3490     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3491         FUNCTION_INST_LOAD_ABBREV)
3492       llvm_unreachable("Unexpected abbrev ordering!");
3493   }
3494   { // INST_UNOP abbrev for FUNCTION_BLOCK.
3495     auto Abbv = std::make_shared<BitCodeAbbrev>();
3496     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3497     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3498     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3499     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3500         FUNCTION_INST_UNOP_ABBREV)
3501       llvm_unreachable("Unexpected abbrev ordering!");
3502   }
3503   { // INST_UNOP_FLAGS abbrev for FUNCTION_BLOCK.
3504     auto Abbv = std::make_shared<BitCodeAbbrev>();
3505     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3506     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3507     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3508     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3509     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3510         FUNCTION_INST_UNOP_FLAGS_ABBREV)
3511       llvm_unreachable("Unexpected abbrev ordering!");
3512   }
3513   { // INST_BINOP abbrev for FUNCTION_BLOCK.
3514     auto Abbv = std::make_shared<BitCodeAbbrev>();
3515     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3516     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3517     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3518     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3519     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3520         FUNCTION_INST_BINOP_ABBREV)
3521       llvm_unreachable("Unexpected abbrev ordering!");
3522   }
3523   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
3524     auto Abbv = std::make_shared<BitCodeAbbrev>();
3525     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3526     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3527     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3528     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3529     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3530     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3531         FUNCTION_INST_BINOP_FLAGS_ABBREV)
3532       llvm_unreachable("Unexpected abbrev ordering!");
3533   }
3534   { // INST_CAST abbrev for FUNCTION_BLOCK.
3535     auto Abbv = std::make_shared<BitCodeAbbrev>();
3536     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
3537     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
3538     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
3539                               VE.computeBitsRequiredForTypeIndicies()));
3540     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
3541     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3542         FUNCTION_INST_CAST_ABBREV)
3543       llvm_unreachable("Unexpected abbrev ordering!");
3544   }
3545 
3546   { // INST_RET abbrev for FUNCTION_BLOCK.
3547     auto Abbv = std::make_shared<BitCodeAbbrev>();
3548     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3549     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3550         FUNCTION_INST_RET_VOID_ABBREV)
3551       llvm_unreachable("Unexpected abbrev ordering!");
3552   }
3553   { // INST_RET abbrev for FUNCTION_BLOCK.
3554     auto Abbv = std::make_shared<BitCodeAbbrev>();
3555     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3556     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
3557     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3558         FUNCTION_INST_RET_VAL_ABBREV)
3559       llvm_unreachable("Unexpected abbrev ordering!");
3560   }
3561   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
3562     auto Abbv = std::make_shared<BitCodeAbbrev>();
3563     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
3564     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3565         FUNCTION_INST_UNREACHABLE_ABBREV)
3566       llvm_unreachable("Unexpected abbrev ordering!");
3567   }
3568   {
3569     auto Abbv = std::make_shared<BitCodeAbbrev>();
3570     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_GEP));
3571     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
3572     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, // dest ty
3573                               Log2_32_Ceil(VE.getTypes().size() + 1)));
3574     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3575     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
3576     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3577         FUNCTION_INST_GEP_ABBREV)
3578       llvm_unreachable("Unexpected abbrev ordering!");
3579   }
3580 
3581   Stream.ExitBlock();
3582 }
3583 
3584 /// Write the module path strings, currently only used when generating
3585 /// a combined index file.
3586 void IndexBitcodeWriter::writeModStrings() {
3587   Stream.EnterSubblock(bitc::MODULE_STRTAB_BLOCK_ID, 3);
3588 
3589   // TODO: See which abbrev sizes we actually need to emit
3590 
3591   // 8-bit fixed-width MST_ENTRY strings.
3592   auto Abbv = std::make_shared<BitCodeAbbrev>();
3593   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3594   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3595   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3596   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3597   unsigned Abbrev8Bit = Stream.EmitAbbrev(std::move(Abbv));
3598 
3599   // 7-bit fixed width MST_ENTRY strings.
3600   Abbv = std::make_shared<BitCodeAbbrev>();
3601   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3602   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3603   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3604   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3605   unsigned Abbrev7Bit = Stream.EmitAbbrev(std::move(Abbv));
3606 
3607   // 6-bit char6 MST_ENTRY strings.
3608   Abbv = std::make_shared<BitCodeAbbrev>();
3609   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3610   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3611   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3612   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3613   unsigned Abbrev6Bit = Stream.EmitAbbrev(std::move(Abbv));
3614 
3615   // Module Hash, 160 bits SHA1. Optionally, emitted after each MST_CODE_ENTRY.
3616   Abbv = std::make_shared<BitCodeAbbrev>();
3617   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_HASH));
3618   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3619   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3620   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3621   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3622   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3623   unsigned AbbrevHash = Stream.EmitAbbrev(std::move(Abbv));
3624 
3625   SmallVector<unsigned, 64> Vals;
3626   forEachModule(
3627       [&](const StringMapEntry<std::pair<uint64_t, ModuleHash>> &MPSE) {
3628         StringRef Key = MPSE.getKey();
3629         const auto &Value = MPSE.getValue();
3630         StringEncoding Bits = getStringEncoding(Key);
3631         unsigned AbbrevToUse = Abbrev8Bit;
3632         if (Bits == SE_Char6)
3633           AbbrevToUse = Abbrev6Bit;
3634         else if (Bits == SE_Fixed7)
3635           AbbrevToUse = Abbrev7Bit;
3636 
3637         Vals.push_back(Value.first);
3638         Vals.append(Key.begin(), Key.end());
3639 
3640         // Emit the finished record.
3641         Stream.EmitRecord(bitc::MST_CODE_ENTRY, Vals, AbbrevToUse);
3642 
3643         // Emit an optional hash for the module now
3644         const auto &Hash = Value.second;
3645         if (llvm::any_of(Hash, [](uint32_t H) { return H; })) {
3646           Vals.assign(Hash.begin(), Hash.end());
3647           // Emit the hash record.
3648           Stream.EmitRecord(bitc::MST_CODE_HASH, Vals, AbbrevHash);
3649         }
3650 
3651         Vals.clear();
3652       });
3653   Stream.ExitBlock();
3654 }
3655 
3656 /// Write the function type metadata related records that need to appear before
3657 /// a function summary entry (whether per-module or combined).
3658 template <typename Fn>
3659 static void writeFunctionTypeMetadataRecords(BitstreamWriter &Stream,
3660                                              FunctionSummary *FS,
3661                                              Fn GetValueID) {
3662   if (!FS->type_tests().empty())
3663     Stream.EmitRecord(bitc::FS_TYPE_TESTS, FS->type_tests());
3664 
3665   SmallVector<uint64_t, 64> Record;
3666 
3667   auto WriteVFuncIdVec = [&](uint64_t Ty,
3668                              ArrayRef<FunctionSummary::VFuncId> VFs) {
3669     if (VFs.empty())
3670       return;
3671     Record.clear();
3672     for (auto &VF : VFs) {
3673       Record.push_back(VF.GUID);
3674       Record.push_back(VF.Offset);
3675     }
3676     Stream.EmitRecord(Ty, Record);
3677   };
3678 
3679   WriteVFuncIdVec(bitc::FS_TYPE_TEST_ASSUME_VCALLS,
3680                   FS->type_test_assume_vcalls());
3681   WriteVFuncIdVec(bitc::FS_TYPE_CHECKED_LOAD_VCALLS,
3682                   FS->type_checked_load_vcalls());
3683 
3684   auto WriteConstVCallVec = [&](uint64_t Ty,
3685                                 ArrayRef<FunctionSummary::ConstVCall> VCs) {
3686     for (auto &VC : VCs) {
3687       Record.clear();
3688       Record.push_back(VC.VFunc.GUID);
3689       Record.push_back(VC.VFunc.Offset);
3690       llvm::append_range(Record, VC.Args);
3691       Stream.EmitRecord(Ty, Record);
3692     }
3693   };
3694 
3695   WriteConstVCallVec(bitc::FS_TYPE_TEST_ASSUME_CONST_VCALL,
3696                      FS->type_test_assume_const_vcalls());
3697   WriteConstVCallVec(bitc::FS_TYPE_CHECKED_LOAD_CONST_VCALL,
3698                      FS->type_checked_load_const_vcalls());
3699 
3700   auto WriteRange = [&](ConstantRange Range) {
3701     Range = Range.sextOrTrunc(FunctionSummary::ParamAccess::RangeWidth);
3702     assert(Range.getLower().getNumWords() == 1);
3703     assert(Range.getUpper().getNumWords() == 1);
3704     emitSignedInt64(Record, *Range.getLower().getRawData());
3705     emitSignedInt64(Record, *Range.getUpper().getRawData());
3706   };
3707 
3708   if (!FS->paramAccesses().empty()) {
3709     Record.clear();
3710     for (auto &Arg : FS->paramAccesses()) {
3711       size_t UndoSize = Record.size();
3712       Record.push_back(Arg.ParamNo);
3713       WriteRange(Arg.Use);
3714       Record.push_back(Arg.Calls.size());
3715       for (auto &Call : Arg.Calls) {
3716         Record.push_back(Call.ParamNo);
3717         Optional<unsigned> ValueID = GetValueID(Call.Callee);
3718         if (!ValueID) {
3719           // If ValueID is unknown we can't drop just this call, we must drop
3720           // entire parameter.
3721           Record.resize(UndoSize);
3722           break;
3723         }
3724         Record.push_back(*ValueID);
3725         WriteRange(Call.Offsets);
3726       }
3727     }
3728     if (!Record.empty())
3729       Stream.EmitRecord(bitc::FS_PARAM_ACCESS, Record);
3730   }
3731 }
3732 
3733 /// Collect type IDs from type tests used by function.
3734 static void
3735 getReferencedTypeIds(FunctionSummary *FS,
3736                      std::set<GlobalValue::GUID> &ReferencedTypeIds) {
3737   if (!FS->type_tests().empty())
3738     for (auto &TT : FS->type_tests())
3739       ReferencedTypeIds.insert(TT);
3740 
3741   auto GetReferencedTypesFromVFuncIdVec =
3742       [&](ArrayRef<FunctionSummary::VFuncId> VFs) {
3743         for (auto &VF : VFs)
3744           ReferencedTypeIds.insert(VF.GUID);
3745       };
3746 
3747   GetReferencedTypesFromVFuncIdVec(FS->type_test_assume_vcalls());
3748   GetReferencedTypesFromVFuncIdVec(FS->type_checked_load_vcalls());
3749 
3750   auto GetReferencedTypesFromConstVCallVec =
3751       [&](ArrayRef<FunctionSummary::ConstVCall> VCs) {
3752         for (auto &VC : VCs)
3753           ReferencedTypeIds.insert(VC.VFunc.GUID);
3754       };
3755 
3756   GetReferencedTypesFromConstVCallVec(FS->type_test_assume_const_vcalls());
3757   GetReferencedTypesFromConstVCallVec(FS->type_checked_load_const_vcalls());
3758 }
3759 
3760 static void writeWholeProgramDevirtResolutionByArg(
3761     SmallVector<uint64_t, 64> &NameVals, const std::vector<uint64_t> &args,
3762     const WholeProgramDevirtResolution::ByArg &ByArg) {
3763   NameVals.push_back(args.size());
3764   llvm::append_range(NameVals, args);
3765 
3766   NameVals.push_back(ByArg.TheKind);
3767   NameVals.push_back(ByArg.Info);
3768   NameVals.push_back(ByArg.Byte);
3769   NameVals.push_back(ByArg.Bit);
3770 }
3771 
3772 static void writeWholeProgramDevirtResolution(
3773     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3774     uint64_t Id, const WholeProgramDevirtResolution &Wpd) {
3775   NameVals.push_back(Id);
3776 
3777   NameVals.push_back(Wpd.TheKind);
3778   NameVals.push_back(StrtabBuilder.add(Wpd.SingleImplName));
3779   NameVals.push_back(Wpd.SingleImplName.size());
3780 
3781   NameVals.push_back(Wpd.ResByArg.size());
3782   for (auto &A : Wpd.ResByArg)
3783     writeWholeProgramDevirtResolutionByArg(NameVals, A.first, A.second);
3784 }
3785 
3786 static void writeTypeIdSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
3787                                      StringTableBuilder &StrtabBuilder,
3788                                      const std::string &Id,
3789                                      const TypeIdSummary &Summary) {
3790   NameVals.push_back(StrtabBuilder.add(Id));
3791   NameVals.push_back(Id.size());
3792 
3793   NameVals.push_back(Summary.TTRes.TheKind);
3794   NameVals.push_back(Summary.TTRes.SizeM1BitWidth);
3795   NameVals.push_back(Summary.TTRes.AlignLog2);
3796   NameVals.push_back(Summary.TTRes.SizeM1);
3797   NameVals.push_back(Summary.TTRes.BitMask);
3798   NameVals.push_back(Summary.TTRes.InlineBits);
3799 
3800   for (auto &W : Summary.WPDRes)
3801     writeWholeProgramDevirtResolution(NameVals, StrtabBuilder, W.first,
3802                                       W.second);
3803 }
3804 
3805 static void writeTypeIdCompatibleVtableSummaryRecord(
3806     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3807     const std::string &Id, const TypeIdCompatibleVtableInfo &Summary,
3808     ValueEnumerator &VE) {
3809   NameVals.push_back(StrtabBuilder.add(Id));
3810   NameVals.push_back(Id.size());
3811 
3812   for (auto &P : Summary) {
3813     NameVals.push_back(P.AddressPointOffset);
3814     NameVals.push_back(VE.getValueID(P.VTableVI.getValue()));
3815   }
3816 }
3817 
3818 // Helper to emit a single function summary record.
3819 void ModuleBitcodeWriterBase::writePerModuleFunctionSummaryRecord(
3820     SmallVector<uint64_t, 64> &NameVals, GlobalValueSummary *Summary,
3821     unsigned ValueID, unsigned FSCallsAbbrev, unsigned FSCallsProfileAbbrev,
3822     const Function &F) {
3823   NameVals.push_back(ValueID);
3824 
3825   FunctionSummary *FS = cast<FunctionSummary>(Summary);
3826 
3827   writeFunctionTypeMetadataRecords(
3828       Stream, FS, [&](const ValueInfo &VI) -> Optional<unsigned> {
3829         return {VE.getValueID(VI.getValue())};
3830       });
3831 
3832   auto SpecialRefCnts = FS->specialRefCounts();
3833   NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
3834   NameVals.push_back(FS->instCount());
3835   NameVals.push_back(getEncodedFFlags(FS->fflags()));
3836   NameVals.push_back(FS->refs().size());
3837   NameVals.push_back(SpecialRefCnts.first);  // rorefcnt
3838   NameVals.push_back(SpecialRefCnts.second); // worefcnt
3839 
3840   for (auto &RI : FS->refs())
3841     NameVals.push_back(VE.getValueID(RI.getValue()));
3842 
3843   bool HasProfileData =
3844       F.hasProfileData() || ForceSummaryEdgesCold != FunctionSummary::FSHT_None;
3845   for (auto &ECI : FS->calls()) {
3846     NameVals.push_back(getValueId(ECI.first));
3847     if (HasProfileData)
3848       NameVals.push_back(static_cast<uint8_t>(ECI.second.Hotness));
3849     else if (WriteRelBFToSummary)
3850       NameVals.push_back(ECI.second.RelBlockFreq);
3851   }
3852 
3853   unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
3854   unsigned Code =
3855       (HasProfileData ? bitc::FS_PERMODULE_PROFILE
3856                       : (WriteRelBFToSummary ? bitc::FS_PERMODULE_RELBF
3857                                              : bitc::FS_PERMODULE));
3858 
3859   // Emit the finished record.
3860   Stream.EmitRecord(Code, NameVals, FSAbbrev);
3861   NameVals.clear();
3862 }
3863 
3864 // Collect the global value references in the given variable's initializer,
3865 // and emit them in a summary record.
3866 void ModuleBitcodeWriterBase::writeModuleLevelReferences(
3867     const GlobalVariable &V, SmallVector<uint64_t, 64> &NameVals,
3868     unsigned FSModRefsAbbrev, unsigned FSModVTableRefsAbbrev) {
3869   auto VI = Index->getValueInfo(V.getGUID());
3870   if (!VI || VI.getSummaryList().empty()) {
3871     // Only declarations should not have a summary (a declaration might however
3872     // have a summary if the def was in module level asm).
3873     assert(V.isDeclaration());
3874     return;
3875   }
3876   auto *Summary = VI.getSummaryList()[0].get();
3877   NameVals.push_back(VE.getValueID(&V));
3878   GlobalVarSummary *VS = cast<GlobalVarSummary>(Summary);
3879   NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
3880   NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
3881 
3882   auto VTableFuncs = VS->vTableFuncs();
3883   if (!VTableFuncs.empty())
3884     NameVals.push_back(VS->refs().size());
3885 
3886   unsigned SizeBeforeRefs = NameVals.size();
3887   for (auto &RI : VS->refs())
3888     NameVals.push_back(VE.getValueID(RI.getValue()));
3889   // Sort the refs for determinism output, the vector returned by FS->refs() has
3890   // been initialized from a DenseSet.
3891   llvm::sort(drop_begin(NameVals, SizeBeforeRefs));
3892 
3893   if (VTableFuncs.empty())
3894     Stream.EmitRecord(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS, NameVals,
3895                       FSModRefsAbbrev);
3896   else {
3897     // VTableFuncs pairs should already be sorted by offset.
3898     for (auto &P : VTableFuncs) {
3899       NameVals.push_back(VE.getValueID(P.FuncVI.getValue()));
3900       NameVals.push_back(P.VTableOffset);
3901     }
3902 
3903     Stream.EmitRecord(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS, NameVals,
3904                       FSModVTableRefsAbbrev);
3905   }
3906   NameVals.clear();
3907 }
3908 
3909 /// Emit the per-module summary section alongside the rest of
3910 /// the module's bitcode.
3911 void ModuleBitcodeWriterBase::writePerModuleGlobalValueSummary() {
3912   // By default we compile with ThinLTO if the module has a summary, but the
3913   // client can request full LTO with a module flag.
3914   bool IsThinLTO = true;
3915   if (auto *MD =
3916           mdconst::extract_or_null<ConstantInt>(M.getModuleFlag("ThinLTO")))
3917     IsThinLTO = MD->getZExtValue();
3918   Stream.EnterSubblock(IsThinLTO ? bitc::GLOBALVAL_SUMMARY_BLOCK_ID
3919                                  : bitc::FULL_LTO_GLOBALVAL_SUMMARY_BLOCK_ID,
3920                        4);
3921 
3922   Stream.EmitRecord(
3923       bitc::FS_VERSION,
3924       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
3925 
3926   // Write the index flags.
3927   uint64_t Flags = 0;
3928   // Bits 1-3 are set only in the combined index, skip them.
3929   if (Index->enableSplitLTOUnit())
3930     Flags |= 0x8;
3931   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Flags});
3932 
3933   if (Index->begin() == Index->end()) {
3934     Stream.ExitBlock();
3935     return;
3936   }
3937 
3938   for (const auto &GVI : valueIds()) {
3939     Stream.EmitRecord(bitc::FS_VALUE_GUID,
3940                       ArrayRef<uint64_t>{GVI.second, GVI.first});
3941   }
3942 
3943   // Abbrev for FS_PERMODULE_PROFILE.
3944   auto Abbv = std::make_shared<BitCodeAbbrev>();
3945   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_PROFILE));
3946   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3947   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3948   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3949   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3950   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3951   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
3952   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
3953   // numrefs x valueid, n x (valueid, hotness)
3954   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3955   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3956   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3957 
3958   // Abbrev for FS_PERMODULE or FS_PERMODULE_RELBF.
3959   Abbv = std::make_shared<BitCodeAbbrev>();
3960   if (WriteRelBFToSummary)
3961     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_RELBF));
3962   else
3963     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE));
3964   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3965   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3966   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3967   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3968   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3969   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
3970   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
3971   // numrefs x valueid, n x (valueid [, rel_block_freq])
3972   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3973   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3974   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3975 
3976   // Abbrev for FS_PERMODULE_GLOBALVAR_INIT_REFS.
3977   Abbv = std::make_shared<BitCodeAbbrev>();
3978   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS));
3979   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
3980   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
3981   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));  // valueids
3982   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3983   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3984 
3985   // Abbrev for FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS.
3986   Abbv = std::make_shared<BitCodeAbbrev>();
3987   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS));
3988   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
3989   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
3990   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numrefs
3991   // numrefs x valueid, n x (valueid , offset)
3992   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3993   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3994   unsigned FSModVTableRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3995 
3996   // Abbrev for FS_ALIAS.
3997   Abbv = std::make_shared<BitCodeAbbrev>();
3998   Abbv->Add(BitCodeAbbrevOp(bitc::FS_ALIAS));
3999   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4000   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4001   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4002   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4003 
4004   // Abbrev for FS_TYPE_ID_METADATA
4005   Abbv = std::make_shared<BitCodeAbbrev>();
4006   Abbv->Add(BitCodeAbbrevOp(bitc::FS_TYPE_ID_METADATA));
4007   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid strtab index
4008   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid length
4009   // n x (valueid , offset)
4010   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4011   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4012   unsigned TypeIdCompatibleVtableAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4013 
4014   SmallVector<uint64_t, 64> NameVals;
4015   // Iterate over the list of functions instead of the Index to
4016   // ensure the ordering is stable.
4017   for (const Function &F : M) {
4018     // Summary emission does not support anonymous functions, they have to
4019     // renamed using the anonymous function renaming pass.
4020     if (!F.hasName())
4021       report_fatal_error("Unexpected anonymous function when writing summary");
4022 
4023     ValueInfo VI = Index->getValueInfo(F.getGUID());
4024     if (!VI || VI.getSummaryList().empty()) {
4025       // Only declarations should not have a summary (a declaration might
4026       // however have a summary if the def was in module level asm).
4027       assert(F.isDeclaration());
4028       continue;
4029     }
4030     auto *Summary = VI.getSummaryList()[0].get();
4031     writePerModuleFunctionSummaryRecord(NameVals, Summary, VE.getValueID(&F),
4032                                         FSCallsAbbrev, FSCallsProfileAbbrev, F);
4033   }
4034 
4035   // Capture references from GlobalVariable initializers, which are outside
4036   // of a function scope.
4037   for (const GlobalVariable &G : M.globals())
4038     writeModuleLevelReferences(G, NameVals, FSModRefsAbbrev,
4039                                FSModVTableRefsAbbrev);
4040 
4041   for (const GlobalAlias &A : M.aliases()) {
4042     auto *Aliasee = A.getBaseObject();
4043     if (!Aliasee->hasName())
4044       // Nameless function don't have an entry in the summary, skip it.
4045       continue;
4046     auto AliasId = VE.getValueID(&A);
4047     auto AliaseeId = VE.getValueID(Aliasee);
4048     NameVals.push_back(AliasId);
4049     auto *Summary = Index->getGlobalValueSummary(A);
4050     AliasSummary *AS = cast<AliasSummary>(Summary);
4051     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
4052     NameVals.push_back(AliaseeId);
4053     Stream.EmitRecord(bitc::FS_ALIAS, NameVals, FSAliasAbbrev);
4054     NameVals.clear();
4055   }
4056 
4057   for (auto &S : Index->typeIdCompatibleVtableMap()) {
4058     writeTypeIdCompatibleVtableSummaryRecord(NameVals, StrtabBuilder, S.first,
4059                                              S.second, VE);
4060     Stream.EmitRecord(bitc::FS_TYPE_ID_METADATA, NameVals,
4061                       TypeIdCompatibleVtableAbbrev);
4062     NameVals.clear();
4063   }
4064 
4065   Stream.EmitRecord(bitc::FS_BLOCK_COUNT,
4066                     ArrayRef<uint64_t>{Index->getBlockCount()});
4067 
4068   Stream.ExitBlock();
4069 }
4070 
4071 /// Emit the combined summary section into the combined index file.
4072 void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
4073   Stream.EnterSubblock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID, 3);
4074   Stream.EmitRecord(
4075       bitc::FS_VERSION,
4076       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
4077 
4078   // Write the index flags.
4079   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Index.getFlags()});
4080 
4081   for (const auto &GVI : valueIds()) {
4082     Stream.EmitRecord(bitc::FS_VALUE_GUID,
4083                       ArrayRef<uint64_t>{GVI.second, GVI.first});
4084   }
4085 
4086   // Abbrev for FS_COMBINED.
4087   auto Abbv = std::make_shared<BitCodeAbbrev>();
4088   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED));
4089   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4090   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4091   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4092   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4093   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4094   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
4095   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4096   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4097   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4098   // numrefs x valueid, n x (valueid)
4099   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4100   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4101   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4102 
4103   // Abbrev for FS_COMBINED_PROFILE.
4104   Abbv = std::make_shared<BitCodeAbbrev>();
4105   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_PROFILE));
4106   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4107   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4108   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4109   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4110   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4111   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
4112   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4113   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4114   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4115   // numrefs x valueid, n x (valueid, hotness)
4116   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4117   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4118   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4119 
4120   // Abbrev for FS_COMBINED_GLOBALVAR_INIT_REFS.
4121   Abbv = std::make_shared<BitCodeAbbrev>();
4122   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS));
4123   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4124   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4125   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4126   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));    // valueids
4127   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4128   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4129 
4130   // Abbrev for FS_COMBINED_ALIAS.
4131   Abbv = std::make_shared<BitCodeAbbrev>();
4132   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_ALIAS));
4133   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4134   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4135   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4136   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4137   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4138 
4139   // The aliases are emitted as a post-pass, and will point to the value
4140   // id of the aliasee. Save them in a vector for post-processing.
4141   SmallVector<AliasSummary *, 64> Aliases;
4142 
4143   // Save the value id for each summary for alias emission.
4144   DenseMap<const GlobalValueSummary *, unsigned> SummaryToValueIdMap;
4145 
4146   SmallVector<uint64_t, 64> NameVals;
4147 
4148   // Set that will be populated during call to writeFunctionTypeMetadataRecords
4149   // with the type ids referenced by this index file.
4150   std::set<GlobalValue::GUID> ReferencedTypeIds;
4151 
4152   // For local linkage, we also emit the original name separately
4153   // immediately after the record.
4154   auto MaybeEmitOriginalName = [&](GlobalValueSummary &S) {
4155     if (!GlobalValue::isLocalLinkage(S.linkage()))
4156       return;
4157     NameVals.push_back(S.getOriginalName());
4158     Stream.EmitRecord(bitc::FS_COMBINED_ORIGINAL_NAME, NameVals);
4159     NameVals.clear();
4160   };
4161 
4162   std::set<GlobalValue::GUID> DefOrUseGUIDs;
4163   forEachSummary([&](GVInfo I, bool IsAliasee) {
4164     GlobalValueSummary *S = I.second;
4165     assert(S);
4166     DefOrUseGUIDs.insert(I.first);
4167     for (const ValueInfo &VI : S->refs())
4168       DefOrUseGUIDs.insert(VI.getGUID());
4169 
4170     auto ValueId = getValueId(I.first);
4171     assert(ValueId);
4172     SummaryToValueIdMap[S] = *ValueId;
4173 
4174     // If this is invoked for an aliasee, we want to record the above
4175     // mapping, but then not emit a summary entry (if the aliasee is
4176     // to be imported, we will invoke this separately with IsAliasee=false).
4177     if (IsAliasee)
4178       return;
4179 
4180     if (auto *AS = dyn_cast<AliasSummary>(S)) {
4181       // Will process aliases as a post-pass because the reader wants all
4182       // global to be loaded first.
4183       Aliases.push_back(AS);
4184       return;
4185     }
4186 
4187     if (auto *VS = dyn_cast<GlobalVarSummary>(S)) {
4188       NameVals.push_back(*ValueId);
4189       NameVals.push_back(Index.getModuleId(VS->modulePath()));
4190       NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
4191       NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
4192       for (auto &RI : VS->refs()) {
4193         auto RefValueId = getValueId(RI.getGUID());
4194         if (!RefValueId)
4195           continue;
4196         NameVals.push_back(*RefValueId);
4197       }
4198 
4199       // Emit the finished record.
4200       Stream.EmitRecord(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS, NameVals,
4201                         FSModRefsAbbrev);
4202       NameVals.clear();
4203       MaybeEmitOriginalName(*S);
4204       return;
4205     }
4206 
4207     auto GetValueId = [&](const ValueInfo &VI) -> Optional<unsigned> {
4208       GlobalValue::GUID GUID = VI.getGUID();
4209       Optional<unsigned> CallValueId = getValueId(GUID);
4210       if (CallValueId)
4211         return CallValueId;
4212       // For SamplePGO, the indirect call targets for local functions will
4213       // have its original name annotated in profile. We try to find the
4214       // corresponding PGOFuncName as the GUID.
4215       GUID = Index.getGUIDFromOriginalID(GUID);
4216       if (!GUID)
4217         return None;
4218       CallValueId = getValueId(GUID);
4219       if (!CallValueId)
4220         return None;
4221       // The mapping from OriginalId to GUID may return a GUID
4222       // that corresponds to a static variable. Filter it out here.
4223       // This can happen when
4224       // 1) There is a call to a library function which does not have
4225       // a CallValidId;
4226       // 2) There is a static variable with the  OriginalGUID identical
4227       // to the GUID of the library function in 1);
4228       // When this happens, the logic for SamplePGO kicks in and
4229       // the static variable in 2) will be found, which needs to be
4230       // filtered out.
4231       auto *GVSum = Index.getGlobalValueSummary(GUID, false);
4232       if (GVSum && GVSum->getSummaryKind() == GlobalValueSummary::GlobalVarKind)
4233         return None;
4234       return CallValueId;
4235     };
4236 
4237     auto *FS = cast<FunctionSummary>(S);
4238     writeFunctionTypeMetadataRecords(Stream, FS, GetValueId);
4239     getReferencedTypeIds(FS, ReferencedTypeIds);
4240 
4241     NameVals.push_back(*ValueId);
4242     NameVals.push_back(Index.getModuleId(FS->modulePath()));
4243     NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
4244     NameVals.push_back(FS->instCount());
4245     NameVals.push_back(getEncodedFFlags(FS->fflags()));
4246     NameVals.push_back(FS->entryCount());
4247 
4248     // Fill in below
4249     NameVals.push_back(0); // numrefs
4250     NameVals.push_back(0); // rorefcnt
4251     NameVals.push_back(0); // worefcnt
4252 
4253     unsigned Count = 0, RORefCnt = 0, WORefCnt = 0;
4254     for (auto &RI : FS->refs()) {
4255       auto RefValueId = getValueId(RI.getGUID());
4256       if (!RefValueId)
4257         continue;
4258       NameVals.push_back(*RefValueId);
4259       if (RI.isReadOnly())
4260         RORefCnt++;
4261       else if (RI.isWriteOnly())
4262         WORefCnt++;
4263       Count++;
4264     }
4265     NameVals[6] = Count;
4266     NameVals[7] = RORefCnt;
4267     NameVals[8] = WORefCnt;
4268 
4269     bool HasProfileData = false;
4270     for (auto &EI : FS->calls()) {
4271       HasProfileData |=
4272           EI.second.getHotness() != CalleeInfo::HotnessType::Unknown;
4273       if (HasProfileData)
4274         break;
4275     }
4276 
4277     for (auto &EI : FS->calls()) {
4278       // If this GUID doesn't have a value id, it doesn't have a function
4279       // summary and we don't need to record any calls to it.
4280       Optional<unsigned> CallValueId = GetValueId(EI.first);
4281       if (!CallValueId)
4282         continue;
4283       NameVals.push_back(*CallValueId);
4284       if (HasProfileData)
4285         NameVals.push_back(static_cast<uint8_t>(EI.second.Hotness));
4286     }
4287 
4288     unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
4289     unsigned Code =
4290         (HasProfileData ? bitc::FS_COMBINED_PROFILE : bitc::FS_COMBINED);
4291 
4292     // Emit the finished record.
4293     Stream.EmitRecord(Code, NameVals, FSAbbrev);
4294     NameVals.clear();
4295     MaybeEmitOriginalName(*S);
4296   });
4297 
4298   for (auto *AS : Aliases) {
4299     auto AliasValueId = SummaryToValueIdMap[AS];
4300     assert(AliasValueId);
4301     NameVals.push_back(AliasValueId);
4302     NameVals.push_back(Index.getModuleId(AS->modulePath()));
4303     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
4304     auto AliaseeValueId = SummaryToValueIdMap[&AS->getAliasee()];
4305     assert(AliaseeValueId);
4306     NameVals.push_back(AliaseeValueId);
4307 
4308     // Emit the finished record.
4309     Stream.EmitRecord(bitc::FS_COMBINED_ALIAS, NameVals, FSAliasAbbrev);
4310     NameVals.clear();
4311     MaybeEmitOriginalName(*AS);
4312 
4313     if (auto *FS = dyn_cast<FunctionSummary>(&AS->getAliasee()))
4314       getReferencedTypeIds(FS, ReferencedTypeIds);
4315   }
4316 
4317   if (!Index.cfiFunctionDefs().empty()) {
4318     for (auto &S : Index.cfiFunctionDefs()) {
4319       if (DefOrUseGUIDs.count(
4320               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4321         NameVals.push_back(StrtabBuilder.add(S));
4322         NameVals.push_back(S.size());
4323       }
4324     }
4325     if (!NameVals.empty()) {
4326       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DEFS, NameVals);
4327       NameVals.clear();
4328     }
4329   }
4330 
4331   if (!Index.cfiFunctionDecls().empty()) {
4332     for (auto &S : Index.cfiFunctionDecls()) {
4333       if (DefOrUseGUIDs.count(
4334               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4335         NameVals.push_back(StrtabBuilder.add(S));
4336         NameVals.push_back(S.size());
4337       }
4338     }
4339     if (!NameVals.empty()) {
4340       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DECLS, NameVals);
4341       NameVals.clear();
4342     }
4343   }
4344 
4345   // Walk the GUIDs that were referenced, and write the
4346   // corresponding type id records.
4347   for (auto &T : ReferencedTypeIds) {
4348     auto TidIter = Index.typeIds().equal_range(T);
4349     for (auto It = TidIter.first; It != TidIter.second; ++It) {
4350       writeTypeIdSummaryRecord(NameVals, StrtabBuilder, It->second.first,
4351                                It->second.second);
4352       Stream.EmitRecord(bitc::FS_TYPE_ID, NameVals);
4353       NameVals.clear();
4354     }
4355   }
4356 
4357   Stream.EmitRecord(bitc::FS_BLOCK_COUNT,
4358                     ArrayRef<uint64_t>{Index.getBlockCount()});
4359 
4360   Stream.ExitBlock();
4361 }
4362 
4363 /// Create the "IDENTIFICATION_BLOCK_ID" containing a single string with the
4364 /// current llvm version, and a record for the epoch number.
4365 static void writeIdentificationBlock(BitstreamWriter &Stream) {
4366   Stream.EnterSubblock(bitc::IDENTIFICATION_BLOCK_ID, 5);
4367 
4368   // Write the "user readable" string identifying the bitcode producer
4369   auto Abbv = std::make_shared<BitCodeAbbrev>();
4370   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_STRING));
4371   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4372   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
4373   auto StringAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4374   writeStringRecord(Stream, bitc::IDENTIFICATION_CODE_STRING,
4375                     "LLVM" LLVM_VERSION_STRING, StringAbbrev);
4376 
4377   // Write the epoch version
4378   Abbv = std::make_shared<BitCodeAbbrev>();
4379   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_EPOCH));
4380   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
4381   auto EpochAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4382   constexpr std::array<unsigned, 1> Vals = {{bitc::BITCODE_CURRENT_EPOCH}};
4383   Stream.EmitRecord(bitc::IDENTIFICATION_CODE_EPOCH, Vals, EpochAbbrev);
4384   Stream.ExitBlock();
4385 }
4386 
4387 void ModuleBitcodeWriter::writeModuleHash(size_t BlockStartPos) {
4388   // Emit the module's hash.
4389   // MODULE_CODE_HASH: [5*i32]
4390   if (GenerateHash) {
4391     uint32_t Vals[5];
4392     Hasher.update(ArrayRef<uint8_t>((const uint8_t *)&(Buffer)[BlockStartPos],
4393                                     Buffer.size() - BlockStartPos));
4394     StringRef Hash = Hasher.result();
4395     for (int Pos = 0; Pos < 20; Pos += 4) {
4396       Vals[Pos / 4] = support::endian::read32be(Hash.data() + Pos);
4397     }
4398 
4399     // Emit the finished record.
4400     Stream.EmitRecord(bitc::MODULE_CODE_HASH, Vals);
4401 
4402     if (ModHash)
4403       // Save the written hash value.
4404       llvm::copy(Vals, std::begin(*ModHash));
4405   }
4406 }
4407 
4408 void ModuleBitcodeWriter::write() {
4409   writeIdentificationBlock(Stream);
4410 
4411   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4412   size_t BlockStartPos = Buffer.size();
4413 
4414   writeModuleVersion();
4415 
4416   // Emit blockinfo, which defines the standard abbreviations etc.
4417   writeBlockInfo();
4418 
4419   // Emit information describing all of the types in the module.
4420   writeTypeTable();
4421 
4422   // Emit information about attribute groups.
4423   writeAttributeGroupTable();
4424 
4425   // Emit information about parameter attributes.
4426   writeAttributeTable();
4427 
4428   writeComdats();
4429 
4430   // Emit top-level description of module, including target triple, inline asm,
4431   // descriptors for global variables, and function prototype info.
4432   writeModuleInfo();
4433 
4434   // Emit constants.
4435   writeModuleConstants();
4436 
4437   // Emit metadata kind names.
4438   writeModuleMetadataKinds();
4439 
4440   // Emit metadata.
4441   writeModuleMetadata();
4442 
4443   // Emit module-level use-lists.
4444   if (VE.shouldPreserveUseListOrder())
4445     writeUseListBlock(nullptr);
4446 
4447   writeOperandBundleTags();
4448   writeSyncScopeNames();
4449 
4450   // Emit function bodies.
4451   DenseMap<const Function *, uint64_t> FunctionToBitcodeIndex;
4452   for (Module::const_iterator F = M.begin(), E = M.end(); F != E; ++F)
4453     if (!F->isDeclaration())
4454       writeFunction(*F, FunctionToBitcodeIndex);
4455 
4456   // Need to write after the above call to WriteFunction which populates
4457   // the summary information in the index.
4458   if (Index)
4459     writePerModuleGlobalValueSummary();
4460 
4461   writeGlobalValueSymbolTable(FunctionToBitcodeIndex);
4462 
4463   writeModuleHash(BlockStartPos);
4464 
4465   Stream.ExitBlock();
4466 }
4467 
4468 static void writeInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
4469                                uint32_t &Position) {
4470   support::endian::write32le(&Buffer[Position], Value);
4471   Position += 4;
4472 }
4473 
4474 /// If generating a bc file on darwin, we have to emit a
4475 /// header and trailer to make it compatible with the system archiver.  To do
4476 /// this we emit the following header, and then emit a trailer that pads the
4477 /// file out to be a multiple of 16 bytes.
4478 ///
4479 /// struct bc_header {
4480 ///   uint32_t Magic;         // 0x0B17C0DE
4481 ///   uint32_t Version;       // Version, currently always 0.
4482 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
4483 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
4484 ///   uint32_t CPUType;       // CPU specifier.
4485 ///   ... potentially more later ...
4486 /// };
4487 static void emitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
4488                                          const Triple &TT) {
4489   unsigned CPUType = ~0U;
4490 
4491   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
4492   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
4493   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
4494   // specific constants here because they are implicitly part of the Darwin ABI.
4495   enum {
4496     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
4497     DARWIN_CPU_TYPE_X86        = 7,
4498     DARWIN_CPU_TYPE_ARM        = 12,
4499     DARWIN_CPU_TYPE_POWERPC    = 18
4500   };
4501 
4502   Triple::ArchType Arch = TT.getArch();
4503   if (Arch == Triple::x86_64)
4504     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
4505   else if (Arch == Triple::x86)
4506     CPUType = DARWIN_CPU_TYPE_X86;
4507   else if (Arch == Triple::ppc)
4508     CPUType = DARWIN_CPU_TYPE_POWERPC;
4509   else if (Arch == Triple::ppc64)
4510     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
4511   else if (Arch == Triple::arm || Arch == Triple::thumb)
4512     CPUType = DARWIN_CPU_TYPE_ARM;
4513 
4514   // Traditional Bitcode starts after header.
4515   assert(Buffer.size() >= BWH_HeaderSize &&
4516          "Expected header size to be reserved");
4517   unsigned BCOffset = BWH_HeaderSize;
4518   unsigned BCSize = Buffer.size() - BWH_HeaderSize;
4519 
4520   // Write the magic and version.
4521   unsigned Position = 0;
4522   writeInt32ToBuffer(0x0B17C0DE, Buffer, Position);
4523   writeInt32ToBuffer(0, Buffer, Position); // Version.
4524   writeInt32ToBuffer(BCOffset, Buffer, Position);
4525   writeInt32ToBuffer(BCSize, Buffer, Position);
4526   writeInt32ToBuffer(CPUType, Buffer, Position);
4527 
4528   // If the file is not a multiple of 16 bytes, insert dummy padding.
4529   while (Buffer.size() & 15)
4530     Buffer.push_back(0);
4531 }
4532 
4533 /// Helper to write the header common to all bitcode files.
4534 static void writeBitcodeHeader(BitstreamWriter &Stream) {
4535   // Emit the file header.
4536   Stream.Emit((unsigned)'B', 8);
4537   Stream.Emit((unsigned)'C', 8);
4538   Stream.Emit(0x0, 4);
4539   Stream.Emit(0xC, 4);
4540   Stream.Emit(0xE, 4);
4541   Stream.Emit(0xD, 4);
4542 }
4543 
4544 BitcodeWriter::BitcodeWriter(SmallVectorImpl<char> &Buffer, raw_fd_stream *FS)
4545     : Buffer(Buffer), Stream(new BitstreamWriter(Buffer, FS, FlushThreshold)) {
4546   writeBitcodeHeader(*Stream);
4547 }
4548 
4549 BitcodeWriter::~BitcodeWriter() { assert(WroteStrtab); }
4550 
4551 void BitcodeWriter::writeBlob(unsigned Block, unsigned Record, StringRef Blob) {
4552   Stream->EnterSubblock(Block, 3);
4553 
4554   auto Abbv = std::make_shared<BitCodeAbbrev>();
4555   Abbv->Add(BitCodeAbbrevOp(Record));
4556   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
4557   auto AbbrevNo = Stream->EmitAbbrev(std::move(Abbv));
4558 
4559   Stream->EmitRecordWithBlob(AbbrevNo, ArrayRef<uint64_t>{Record}, Blob);
4560 
4561   Stream->ExitBlock();
4562 }
4563 
4564 void BitcodeWriter::writeSymtab() {
4565   assert(!WroteStrtab && !WroteSymtab);
4566 
4567   // If any module has module-level inline asm, we will require a registered asm
4568   // parser for the target so that we can create an accurate symbol table for
4569   // the module.
4570   for (Module *M : Mods) {
4571     if (M->getModuleInlineAsm().empty())
4572       continue;
4573 
4574     std::string Err;
4575     const Triple TT(M->getTargetTriple());
4576     const Target *T = TargetRegistry::lookupTarget(TT.str(), Err);
4577     if (!T || !T->hasMCAsmParser())
4578       return;
4579   }
4580 
4581   WroteSymtab = true;
4582   SmallVector<char, 0> Symtab;
4583   // The irsymtab::build function may be unable to create a symbol table if the
4584   // module is malformed (e.g. it contains an invalid alias). Writing a symbol
4585   // table is not required for correctness, but we still want to be able to
4586   // write malformed modules to bitcode files, so swallow the error.
4587   if (Error E = irsymtab::build(Mods, Symtab, StrtabBuilder, Alloc)) {
4588     consumeError(std::move(E));
4589     return;
4590   }
4591 
4592   writeBlob(bitc::SYMTAB_BLOCK_ID, bitc::SYMTAB_BLOB,
4593             {Symtab.data(), Symtab.size()});
4594 }
4595 
4596 void BitcodeWriter::writeStrtab() {
4597   assert(!WroteStrtab);
4598 
4599   std::vector<char> Strtab;
4600   StrtabBuilder.finalizeInOrder();
4601   Strtab.resize(StrtabBuilder.getSize());
4602   StrtabBuilder.write((uint8_t *)Strtab.data());
4603 
4604   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB,
4605             {Strtab.data(), Strtab.size()});
4606 
4607   WroteStrtab = true;
4608 }
4609 
4610 void BitcodeWriter::copyStrtab(StringRef Strtab) {
4611   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB, Strtab);
4612   WroteStrtab = true;
4613 }
4614 
4615 void BitcodeWriter::writeModule(const Module &M,
4616                                 bool ShouldPreserveUseListOrder,
4617                                 const ModuleSummaryIndex *Index,
4618                                 bool GenerateHash, ModuleHash *ModHash) {
4619   assert(!WroteStrtab);
4620 
4621   // The Mods vector is used by irsymtab::build, which requires non-const
4622   // Modules in case it needs to materialize metadata. But the bitcode writer
4623   // requires that the module is materialized, so we can cast to non-const here,
4624   // after checking that it is in fact materialized.
4625   assert(M.isMaterialized());
4626   Mods.push_back(const_cast<Module *>(&M));
4627 
4628   ModuleBitcodeWriter ModuleWriter(M, Buffer, StrtabBuilder, *Stream,
4629                                    ShouldPreserveUseListOrder, Index,
4630                                    GenerateHash, ModHash);
4631   ModuleWriter.write();
4632 }
4633 
4634 void BitcodeWriter::writeIndex(
4635     const ModuleSummaryIndex *Index,
4636     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4637   IndexBitcodeWriter IndexWriter(*Stream, StrtabBuilder, *Index,
4638                                  ModuleToSummariesForIndex);
4639   IndexWriter.write();
4640 }
4641 
4642 /// Write the specified module to the specified output stream.
4643 void llvm::WriteBitcodeToFile(const Module &M, raw_ostream &Out,
4644                               bool ShouldPreserveUseListOrder,
4645                               const ModuleSummaryIndex *Index,
4646                               bool GenerateHash, ModuleHash *ModHash) {
4647   SmallVector<char, 0> Buffer;
4648   Buffer.reserve(256*1024);
4649 
4650   // If this is darwin or another generic macho target, reserve space for the
4651   // header.
4652   Triple TT(M.getTargetTriple());
4653   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4654     Buffer.insert(Buffer.begin(), BWH_HeaderSize, 0);
4655 
4656   BitcodeWriter Writer(Buffer, dyn_cast<raw_fd_stream>(&Out));
4657   Writer.writeModule(M, ShouldPreserveUseListOrder, Index, GenerateHash,
4658                      ModHash);
4659   Writer.writeSymtab();
4660   Writer.writeStrtab();
4661 
4662   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4663     emitDarwinBCHeaderAndTrailer(Buffer, TT);
4664 
4665   // Write the generated bitstream to "Out".
4666   if (!Buffer.empty())
4667     Out.write((char *)&Buffer.front(), Buffer.size());
4668 }
4669 
4670 void IndexBitcodeWriter::write() {
4671   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4672 
4673   writeModuleVersion();
4674 
4675   // Write the module paths in the combined index.
4676   writeModStrings();
4677 
4678   // Write the summary combined index records.
4679   writeCombinedGlobalValueSummary();
4680 
4681   Stream.ExitBlock();
4682 }
4683 
4684 // Write the specified module summary index to the given raw output stream,
4685 // where it will be written in a new bitcode block. This is used when
4686 // writing the combined index file for ThinLTO. When writing a subset of the
4687 // index for a distributed backend, provide a \p ModuleToSummariesForIndex map.
4688 void llvm::WriteIndexToFile(
4689     const ModuleSummaryIndex &Index, raw_ostream &Out,
4690     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4691   SmallVector<char, 0> Buffer;
4692   Buffer.reserve(256 * 1024);
4693 
4694   BitcodeWriter Writer(Buffer);
4695   Writer.writeIndex(&Index, ModuleToSummariesForIndex);
4696   Writer.writeStrtab();
4697 
4698   Out.write((char *)&Buffer.front(), Buffer.size());
4699 }
4700 
4701 namespace {
4702 
4703 /// Class to manage the bitcode writing for a thin link bitcode file.
4704 class ThinLinkBitcodeWriter : public ModuleBitcodeWriterBase {
4705   /// ModHash is for use in ThinLTO incremental build, generated while writing
4706   /// the module bitcode file.
4707   const ModuleHash *ModHash;
4708 
4709 public:
4710   ThinLinkBitcodeWriter(const Module &M, StringTableBuilder &StrtabBuilder,
4711                         BitstreamWriter &Stream,
4712                         const ModuleSummaryIndex &Index,
4713                         const ModuleHash &ModHash)
4714       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
4715                                 /*ShouldPreserveUseListOrder=*/false, &Index),
4716         ModHash(&ModHash) {}
4717 
4718   void write();
4719 
4720 private:
4721   void writeSimplifiedModuleInfo();
4722 };
4723 
4724 } // end anonymous namespace
4725 
4726 // This function writes a simpilified module info for thin link bitcode file.
4727 // It only contains the source file name along with the name(the offset and
4728 // size in strtab) and linkage for global values. For the global value info
4729 // entry, in order to keep linkage at offset 5, there are three zeros used
4730 // as padding.
4731 void ThinLinkBitcodeWriter::writeSimplifiedModuleInfo() {
4732   SmallVector<unsigned, 64> Vals;
4733   // Emit the module's source file name.
4734   {
4735     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
4736     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
4737     if (Bits == SE_Char6)
4738       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
4739     else if (Bits == SE_Fixed7)
4740       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
4741 
4742     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
4743     auto Abbv = std::make_shared<BitCodeAbbrev>();
4744     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
4745     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4746     Abbv->Add(AbbrevOpToUse);
4747     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4748 
4749     for (const auto P : M.getSourceFileName())
4750       Vals.push_back((unsigned char)P);
4751 
4752     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
4753     Vals.clear();
4754   }
4755 
4756   // Emit the global variable information.
4757   for (const GlobalVariable &GV : M.globals()) {
4758     // GLOBALVAR: [strtab offset, strtab size, 0, 0, 0, linkage]
4759     Vals.push_back(StrtabBuilder.add(GV.getName()));
4760     Vals.push_back(GV.getName().size());
4761     Vals.push_back(0);
4762     Vals.push_back(0);
4763     Vals.push_back(0);
4764     Vals.push_back(getEncodedLinkage(GV));
4765 
4766     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals);
4767     Vals.clear();
4768   }
4769 
4770   // Emit the function proto information.
4771   for (const Function &F : M) {
4772     // FUNCTION:  [strtab offset, strtab size, 0, 0, 0, linkage]
4773     Vals.push_back(StrtabBuilder.add(F.getName()));
4774     Vals.push_back(F.getName().size());
4775     Vals.push_back(0);
4776     Vals.push_back(0);
4777     Vals.push_back(0);
4778     Vals.push_back(getEncodedLinkage(F));
4779 
4780     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals);
4781     Vals.clear();
4782   }
4783 
4784   // Emit the alias information.
4785   for (const GlobalAlias &A : M.aliases()) {
4786     // ALIAS: [strtab offset, strtab size, 0, 0, 0, linkage]
4787     Vals.push_back(StrtabBuilder.add(A.getName()));
4788     Vals.push_back(A.getName().size());
4789     Vals.push_back(0);
4790     Vals.push_back(0);
4791     Vals.push_back(0);
4792     Vals.push_back(getEncodedLinkage(A));
4793 
4794     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals);
4795     Vals.clear();
4796   }
4797 
4798   // Emit the ifunc information.
4799   for (const GlobalIFunc &I : M.ifuncs()) {
4800     // IFUNC: [strtab offset, strtab size, 0, 0, 0, linkage]
4801     Vals.push_back(StrtabBuilder.add(I.getName()));
4802     Vals.push_back(I.getName().size());
4803     Vals.push_back(0);
4804     Vals.push_back(0);
4805     Vals.push_back(0);
4806     Vals.push_back(getEncodedLinkage(I));
4807 
4808     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
4809     Vals.clear();
4810   }
4811 }
4812 
4813 void ThinLinkBitcodeWriter::write() {
4814   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4815 
4816   writeModuleVersion();
4817 
4818   writeSimplifiedModuleInfo();
4819 
4820   writePerModuleGlobalValueSummary();
4821 
4822   // Write module hash.
4823   Stream.EmitRecord(bitc::MODULE_CODE_HASH, ArrayRef<uint32_t>(*ModHash));
4824 
4825   Stream.ExitBlock();
4826 }
4827 
4828 void BitcodeWriter::writeThinLinkBitcode(const Module &M,
4829                                          const ModuleSummaryIndex &Index,
4830                                          const ModuleHash &ModHash) {
4831   assert(!WroteStrtab);
4832 
4833   // The Mods vector is used by irsymtab::build, which requires non-const
4834   // Modules in case it needs to materialize metadata. But the bitcode writer
4835   // requires that the module is materialized, so we can cast to non-const here,
4836   // after checking that it is in fact materialized.
4837   assert(M.isMaterialized());
4838   Mods.push_back(const_cast<Module *>(&M));
4839 
4840   ThinLinkBitcodeWriter ThinLinkWriter(M, StrtabBuilder, *Stream, Index,
4841                                        ModHash);
4842   ThinLinkWriter.write();
4843 }
4844 
4845 // Write the specified thin link bitcode file to the given raw output stream,
4846 // where it will be written in a new bitcode block. This is used when
4847 // writing the per-module index file for ThinLTO.
4848 void llvm::WriteThinLinkBitcodeToFile(const Module &M, raw_ostream &Out,
4849                                       const ModuleSummaryIndex &Index,
4850                                       const ModuleHash &ModHash) {
4851   SmallVector<char, 0> Buffer;
4852   Buffer.reserve(256 * 1024);
4853 
4854   BitcodeWriter Writer(Buffer);
4855   Writer.writeThinLinkBitcode(M, Index, ModHash);
4856   Writer.writeSymtab();
4857   Writer.writeStrtab();
4858 
4859   Out.write((char *)&Buffer.front(), Buffer.size());
4860 }
4861 
4862 static const char *getSectionNameForBitcode(const Triple &T) {
4863   switch (T.getObjectFormat()) {
4864   case Triple::MachO:
4865     return "__LLVM,__bitcode";
4866   case Triple::COFF:
4867   case Triple::ELF:
4868   case Triple::Wasm:
4869   case Triple::UnknownObjectFormat:
4870     return ".llvmbc";
4871   case Triple::GOFF:
4872     llvm_unreachable("GOFF is not yet implemented");
4873     break;
4874   case Triple::XCOFF:
4875     llvm_unreachable("XCOFF is not yet implemented");
4876     break;
4877   }
4878   llvm_unreachable("Unimplemented ObjectFormatType");
4879 }
4880 
4881 static const char *getSectionNameForCommandline(const Triple &T) {
4882   switch (T.getObjectFormat()) {
4883   case Triple::MachO:
4884     return "__LLVM,__cmdline";
4885   case Triple::COFF:
4886   case Triple::ELF:
4887   case Triple::Wasm:
4888   case Triple::UnknownObjectFormat:
4889     return ".llvmcmd";
4890   case Triple::GOFF:
4891     llvm_unreachable("GOFF is not yet implemented");
4892     break;
4893   case Triple::XCOFF:
4894     llvm_unreachable("XCOFF is not yet implemented");
4895     break;
4896   }
4897   llvm_unreachable("Unimplemented ObjectFormatType");
4898 }
4899 
4900 void llvm::EmbedBitcodeInModule(llvm::Module &M, llvm::MemoryBufferRef Buf,
4901                                 bool EmbedBitcode, bool EmbedCmdline,
4902                                 const std::vector<uint8_t> &CmdArgs) {
4903   // Save llvm.compiler.used and remove it.
4904   SmallVector<Constant *, 2> UsedArray;
4905   SmallVector<GlobalValue *, 4> UsedGlobals;
4906   Type *UsedElementType = Type::getInt8Ty(M.getContext())->getPointerTo(0);
4907   GlobalVariable *Used = collectUsedGlobalVariables(M, UsedGlobals, true);
4908   for (auto *GV : UsedGlobals) {
4909     if (GV->getName() != "llvm.embedded.module" &&
4910         GV->getName() != "llvm.cmdline")
4911       UsedArray.push_back(
4912           ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
4913   }
4914   if (Used)
4915     Used->eraseFromParent();
4916 
4917   // Embed the bitcode for the llvm module.
4918   std::string Data;
4919   ArrayRef<uint8_t> ModuleData;
4920   Triple T(M.getTargetTriple());
4921 
4922   if (EmbedBitcode) {
4923     if (Buf.getBufferSize() == 0 ||
4924         !isBitcode((const unsigned char *)Buf.getBufferStart(),
4925                    (const unsigned char *)Buf.getBufferEnd())) {
4926       // If the input is LLVM Assembly, bitcode is produced by serializing
4927       // the module. Use-lists order need to be preserved in this case.
4928       llvm::raw_string_ostream OS(Data);
4929       llvm::WriteBitcodeToFile(M, OS, /* ShouldPreserveUseListOrder */ true);
4930       ModuleData =
4931           ArrayRef<uint8_t>((const uint8_t *)OS.str().data(), OS.str().size());
4932     } else
4933       // If the input is LLVM bitcode, write the input byte stream directly.
4934       ModuleData = ArrayRef<uint8_t>((const uint8_t *)Buf.getBufferStart(),
4935                                      Buf.getBufferSize());
4936   }
4937   llvm::Constant *ModuleConstant =
4938       llvm::ConstantDataArray::get(M.getContext(), ModuleData);
4939   llvm::GlobalVariable *GV = new llvm::GlobalVariable(
4940       M, ModuleConstant->getType(), true, llvm::GlobalValue::PrivateLinkage,
4941       ModuleConstant);
4942   GV->setSection(getSectionNameForBitcode(T));
4943   // Set alignment to 1 to prevent padding between two contributions from input
4944   // sections after linking.
4945   GV->setAlignment(Align(1));
4946   UsedArray.push_back(
4947       ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
4948   if (llvm::GlobalVariable *Old =
4949           M.getGlobalVariable("llvm.embedded.module", true)) {
4950     assert(Old->hasOneUse() &&
4951            "llvm.embedded.module can only be used once in llvm.compiler.used");
4952     GV->takeName(Old);
4953     Old->eraseFromParent();
4954   } else {
4955     GV->setName("llvm.embedded.module");
4956   }
4957 
4958   // Skip if only bitcode needs to be embedded.
4959   if (EmbedCmdline) {
4960     // Embed command-line options.
4961     ArrayRef<uint8_t> CmdData(const_cast<uint8_t *>(CmdArgs.data()),
4962                               CmdArgs.size());
4963     llvm::Constant *CmdConstant =
4964         llvm::ConstantDataArray::get(M.getContext(), CmdData);
4965     GV = new llvm::GlobalVariable(M, CmdConstant->getType(), true,
4966                                   llvm::GlobalValue::PrivateLinkage,
4967                                   CmdConstant);
4968     GV->setSection(getSectionNameForCommandline(T));
4969     GV->setAlignment(Align(1));
4970     UsedArray.push_back(
4971         ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
4972     if (llvm::GlobalVariable *Old = M.getGlobalVariable("llvm.cmdline", true)) {
4973       assert(Old->hasOneUse() &&
4974              "llvm.cmdline can only be used once in llvm.compiler.used");
4975       GV->takeName(Old);
4976       Old->eraseFromParent();
4977     } else {
4978       GV->setName("llvm.cmdline");
4979     }
4980   }
4981 
4982   if (UsedArray.empty())
4983     return;
4984 
4985   // Recreate llvm.compiler.used.
4986   ArrayType *ATy = ArrayType::get(UsedElementType, UsedArray.size());
4987   auto *NewUsed = new GlobalVariable(
4988       M, ATy, false, llvm::GlobalValue::AppendingLinkage,
4989       llvm::ConstantArray::get(ATy, UsedArray), "llvm.compiler.used");
4990   NewUsed->setSection("llvm.metadata");
4991 }
4992