xref: /llvm-project/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp (revision d664c4b73c5dc994d4caa6c70bb5e59ada414b90)
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/MC/TargetRegistry.h"
62 #include "llvm/Object/IRSymtab.h"
63 #include "llvm/Support/AtomicOrdering.h"
64 #include "llvm/Support/Casting.h"
65 #include "llvm/Support/CommandLine.h"
66 #include "llvm/Support/Endian.h"
67 #include "llvm/Support/Error.h"
68 #include "llvm/Support/ErrorHandling.h"
69 #include "llvm/Support/MathExtras.h"
70 #include "llvm/Support/SHA1.h"
71 #include "llvm/Support/raw_ostream.h"
72 #include <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 writeModuleVersion();
146 };
147 
148 void BitcodeWriterBase::writeModuleVersion() {
149   // VERSION: [version#]
150   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, ArrayRef<uint64_t>{2});
151 }
152 
153 /// Base class to manage the module bitcode writing, currently subclassed for
154 /// ModuleBitcodeWriter and ThinLinkBitcodeWriter.
155 class ModuleBitcodeWriterBase : public BitcodeWriterBase {
156 protected:
157   /// The Module to write to bitcode.
158   const Module &M;
159 
160   /// Enumerates ids for all values in the module.
161   ValueEnumerator VE;
162 
163   /// Optional per-module index to write for ThinLTO.
164   const ModuleSummaryIndex *Index;
165 
166   /// Map that holds the correspondence between GUIDs in the summary index,
167   /// that came from indirect call profiles, and a value id generated by this
168   /// class to use in the VST and summary block records.
169   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
170 
171   /// Tracks the last value id recorded in the GUIDToValueMap.
172   unsigned GlobalValueId;
173 
174   /// Saves the offset of the VSTOffset record that must eventually be
175   /// backpatched with the offset of the actual VST.
176   uint64_t VSTOffsetPlaceholder = 0;
177 
178 public:
179   /// Constructs a ModuleBitcodeWriterBase object for the given Module,
180   /// writing to the provided \p Buffer.
181   ModuleBitcodeWriterBase(const Module &M, StringTableBuilder &StrtabBuilder,
182                           BitstreamWriter &Stream,
183                           bool ShouldPreserveUseListOrder,
184                           const ModuleSummaryIndex *Index)
185       : BitcodeWriterBase(Stream, StrtabBuilder), M(M),
186         VE(M, ShouldPreserveUseListOrder), Index(Index) {
187     // Assign ValueIds to any callee values in the index that came from
188     // indirect call profiles and were recorded as a GUID not a Value*
189     // (which would have been assigned an ID by the ValueEnumerator).
190     // The starting ValueId is just after the number of values in the
191     // ValueEnumerator, so that they can be emitted in the VST.
192     GlobalValueId = VE.getValues().size();
193     if (!Index)
194       return;
195     for (const auto &GUIDSummaryLists : *Index)
196       // Examine all summaries for this GUID.
197       for (auto &Summary : GUIDSummaryLists.second.SummaryList)
198         if (auto FS = dyn_cast<FunctionSummary>(Summary.get()))
199           // For each call in the function summary, see if the call
200           // is to a GUID (which means it is for an indirect call,
201           // otherwise we would have a Value for it). If so, synthesize
202           // a value id.
203           for (auto &CallEdge : FS->calls())
204             if (!CallEdge.first.haveGVs() || !CallEdge.first.getValue())
205               assignValueId(CallEdge.first.getGUID());
206   }
207 
208 protected:
209   void writePerModuleGlobalValueSummary();
210 
211 private:
212   void writePerModuleFunctionSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
213                                            GlobalValueSummary *Summary,
214                                            unsigned ValueID,
215                                            unsigned FSCallsAbbrev,
216                                            unsigned FSCallsProfileAbbrev,
217                                            const Function &F);
218   void writeModuleLevelReferences(const GlobalVariable &V,
219                                   SmallVector<uint64_t, 64> &NameVals,
220                                   unsigned FSModRefsAbbrev,
221                                   unsigned FSModVTableRefsAbbrev);
222 
223   void assignValueId(GlobalValue::GUID ValGUID) {
224     GUIDToValueIdMap[ValGUID] = ++GlobalValueId;
225   }
226 
227   unsigned getValueId(GlobalValue::GUID ValGUID) {
228     const auto &VMI = GUIDToValueIdMap.find(ValGUID);
229     // Expect that any GUID value had a value Id assigned by an
230     // earlier call to assignValueId.
231     assert(VMI != GUIDToValueIdMap.end() &&
232            "GUID does not have assigned value Id");
233     return VMI->second;
234   }
235 
236   // Helper to get the valueId for the type of value recorded in VI.
237   unsigned getValueId(ValueInfo VI) {
238     if (!VI.haveGVs() || !VI.getValue())
239       return getValueId(VI.getGUID());
240     return VE.getValueID(VI.getValue());
241   }
242 
243   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
244 };
245 
246 /// Class to manage the bitcode writing for a module.
247 class ModuleBitcodeWriter : public ModuleBitcodeWriterBase {
248   /// Pointer to the buffer allocated by caller for bitcode writing.
249   const SmallVectorImpl<char> &Buffer;
250 
251   /// True if a module hash record should be written.
252   bool GenerateHash;
253 
254   /// If non-null, when GenerateHash is true, the resulting hash is written
255   /// into ModHash.
256   ModuleHash *ModHash;
257 
258   SHA1 Hasher;
259 
260   /// The start bit of the identification block.
261   uint64_t BitcodeStartBit;
262 
263 public:
264   /// Constructs a ModuleBitcodeWriter object for the given Module,
265   /// writing to the provided \p Buffer.
266   ModuleBitcodeWriter(const Module &M, SmallVectorImpl<char> &Buffer,
267                       StringTableBuilder &StrtabBuilder,
268                       BitstreamWriter &Stream, bool ShouldPreserveUseListOrder,
269                       const ModuleSummaryIndex *Index, bool GenerateHash,
270                       ModuleHash *ModHash = nullptr)
271       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
272                                 ShouldPreserveUseListOrder, Index),
273         Buffer(Buffer), GenerateHash(GenerateHash), ModHash(ModHash),
274         BitcodeStartBit(Stream.GetCurrentBitNo()) {}
275 
276   /// Emit the current module to the bitstream.
277   void write();
278 
279 private:
280   uint64_t bitcodeStartBit() { return BitcodeStartBit; }
281 
282   size_t addToStrtab(StringRef Str);
283 
284   void writeAttributeGroupTable();
285   void writeAttributeTable();
286   void writeTypeTable();
287   void writeComdats();
288   void writeValueSymbolTableForwardDecl();
289   void writeModuleInfo();
290   void writeValueAsMetadata(const ValueAsMetadata *MD,
291                             SmallVectorImpl<uint64_t> &Record);
292   void writeMDTuple(const MDTuple *N, SmallVectorImpl<uint64_t> &Record,
293                     unsigned Abbrev);
294   unsigned createDILocationAbbrev();
295   void writeDILocation(const DILocation *N, SmallVectorImpl<uint64_t> &Record,
296                        unsigned &Abbrev);
297   unsigned createGenericDINodeAbbrev();
298   void writeGenericDINode(const GenericDINode *N,
299                           SmallVectorImpl<uint64_t> &Record, unsigned &Abbrev);
300   void writeDISubrange(const DISubrange *N, SmallVectorImpl<uint64_t> &Record,
301                        unsigned Abbrev);
302   void writeDIGenericSubrange(const DIGenericSubrange *N,
303                               SmallVectorImpl<uint64_t> &Record,
304                               unsigned Abbrev);
305   void writeDIEnumerator(const DIEnumerator *N,
306                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
307   void writeDIBasicType(const DIBasicType *N, SmallVectorImpl<uint64_t> &Record,
308                         unsigned Abbrev);
309   void writeDIStringType(const DIStringType *N,
310                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
311   void writeDIDerivedType(const DIDerivedType *N,
312                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
313   void writeDICompositeType(const DICompositeType *N,
314                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
315   void writeDISubroutineType(const DISubroutineType *N,
316                              SmallVectorImpl<uint64_t> &Record,
317                              unsigned Abbrev);
318   void writeDIFile(const DIFile *N, SmallVectorImpl<uint64_t> &Record,
319                    unsigned Abbrev);
320   void writeDICompileUnit(const DICompileUnit *N,
321                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
322   void writeDISubprogram(const DISubprogram *N,
323                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
324   void writeDILexicalBlock(const DILexicalBlock *N,
325                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
326   void writeDILexicalBlockFile(const DILexicalBlockFile *N,
327                                SmallVectorImpl<uint64_t> &Record,
328                                unsigned Abbrev);
329   void writeDICommonBlock(const DICommonBlock *N,
330                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
331   void writeDINamespace(const DINamespace *N, SmallVectorImpl<uint64_t> &Record,
332                         unsigned Abbrev);
333   void writeDIMacro(const DIMacro *N, SmallVectorImpl<uint64_t> &Record,
334                     unsigned Abbrev);
335   void writeDIMacroFile(const DIMacroFile *N, SmallVectorImpl<uint64_t> &Record,
336                         unsigned Abbrev);
337   void writeDIArgList(const DIArgList *N, SmallVectorImpl<uint64_t> &Record,
338                       unsigned Abbrev);
339   void writeDIModule(const DIModule *N, SmallVectorImpl<uint64_t> &Record,
340                      unsigned Abbrev);
341   void writeDITemplateTypeParameter(const DITemplateTypeParameter *N,
342                                     SmallVectorImpl<uint64_t> &Record,
343                                     unsigned Abbrev);
344   void writeDITemplateValueParameter(const DITemplateValueParameter *N,
345                                      SmallVectorImpl<uint64_t> &Record,
346                                      unsigned Abbrev);
347   void writeDIGlobalVariable(const DIGlobalVariable *N,
348                              SmallVectorImpl<uint64_t> &Record,
349                              unsigned Abbrev);
350   void writeDILocalVariable(const DILocalVariable *N,
351                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
352   void writeDILabel(const DILabel *N,
353                     SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
354   void writeDIExpression(const DIExpression *N,
355                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
356   void writeDIGlobalVariableExpression(const DIGlobalVariableExpression *N,
357                                        SmallVectorImpl<uint64_t> &Record,
358                                        unsigned Abbrev);
359   void writeDIObjCProperty(const DIObjCProperty *N,
360                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
361   void writeDIImportedEntity(const DIImportedEntity *N,
362                              SmallVectorImpl<uint64_t> &Record,
363                              unsigned Abbrev);
364   unsigned createNamedMetadataAbbrev();
365   void writeNamedMetadata(SmallVectorImpl<uint64_t> &Record);
366   unsigned createMetadataStringsAbbrev();
367   void writeMetadataStrings(ArrayRef<const Metadata *> Strings,
368                             SmallVectorImpl<uint64_t> &Record);
369   void writeMetadataRecords(ArrayRef<const Metadata *> MDs,
370                             SmallVectorImpl<uint64_t> &Record,
371                             std::vector<unsigned> *MDAbbrevs = nullptr,
372                             std::vector<uint64_t> *IndexPos = nullptr);
373   void writeModuleMetadata();
374   void writeFunctionMetadata(const Function &F);
375   void writeFunctionMetadataAttachment(const Function &F);
376   void pushGlobalMetadataAttachment(SmallVectorImpl<uint64_t> &Record,
377                                     const GlobalObject &GO);
378   void writeModuleMetadataKinds();
379   void writeOperandBundleTags();
380   void writeSyncScopeNames();
381   void writeConstants(unsigned FirstVal, unsigned LastVal, bool isGlobal);
382   void writeModuleConstants();
383   bool pushValueAndType(const Value *V, unsigned InstID,
384                         SmallVectorImpl<unsigned> &Vals);
385   void writeOperandBundles(const CallBase &CB, unsigned InstID);
386   void pushValue(const Value *V, unsigned InstID,
387                  SmallVectorImpl<unsigned> &Vals);
388   void pushValueSigned(const Value *V, unsigned InstID,
389                        SmallVectorImpl<uint64_t> &Vals);
390   void writeInstruction(const Instruction &I, unsigned InstID,
391                         SmallVectorImpl<unsigned> &Vals);
392   void writeFunctionLevelValueSymbolTable(const ValueSymbolTable &VST);
393   void writeGlobalValueSymbolTable(
394       DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
395   void writeUseList(UseListOrder &&Order);
396   void writeUseListBlock(const Function *F);
397   void
398   writeFunction(const Function &F,
399                 DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
400   void writeBlockInfo();
401   void writeModuleHash(size_t BlockStartPos);
402 
403   unsigned getEncodedSyncScopeID(SyncScope::ID SSID) {
404     return unsigned(SSID);
405   }
406 
407   unsigned getEncodedAlign(MaybeAlign Alignment) { return encode(Alignment); }
408 };
409 
410 /// Class to manage the bitcode writing for a combined index.
411 class IndexBitcodeWriter : public BitcodeWriterBase {
412   /// The combined index to write to bitcode.
413   const ModuleSummaryIndex &Index;
414 
415   /// When writing a subset of the index for distributed backends, client
416   /// provides a map of modules to the corresponding GUIDs/summaries to write.
417   const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex;
418 
419   /// Map that holds the correspondence between the GUID used in the combined
420   /// index and a value id generated by this class to use in references.
421   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
422 
423   /// Tracks the last value id recorded in the GUIDToValueMap.
424   unsigned GlobalValueId = 0;
425 
426 public:
427   /// Constructs a IndexBitcodeWriter object for the given combined index,
428   /// writing to the provided \p Buffer. When writing a subset of the index
429   /// for a distributed backend, provide a \p ModuleToSummariesForIndex map.
430   IndexBitcodeWriter(BitstreamWriter &Stream, StringTableBuilder &StrtabBuilder,
431                      const ModuleSummaryIndex &Index,
432                      const std::map<std::string, GVSummaryMapTy>
433                          *ModuleToSummariesForIndex = nullptr)
434       : BitcodeWriterBase(Stream, StrtabBuilder), Index(Index),
435         ModuleToSummariesForIndex(ModuleToSummariesForIndex) {
436     // Assign unique value ids to all summaries to be written, for use
437     // in writing out the call graph edges. Save the mapping from GUID
438     // to the new global value id to use when writing those edges, which
439     // are currently saved in the index in terms of GUID.
440     forEachSummary([&](GVInfo I, bool) {
441       GUIDToValueIdMap[I.first] = ++GlobalValueId;
442     });
443   }
444 
445   /// The below iterator returns the GUID and associated summary.
446   using GVInfo = std::pair<GlobalValue::GUID, GlobalValueSummary *>;
447 
448   /// Calls the callback for each value GUID and summary to be written to
449   /// bitcode. This hides the details of whether they are being pulled from the
450   /// entire index or just those in a provided ModuleToSummariesForIndex map.
451   template<typename Functor>
452   void forEachSummary(Functor Callback) {
453     if (ModuleToSummariesForIndex) {
454       for (auto &M : *ModuleToSummariesForIndex)
455         for (auto &Summary : M.second) {
456           Callback(Summary, false);
457           // Ensure aliasee is handled, e.g. for assigning a valueId,
458           // even if we are not importing the aliasee directly (the
459           // imported alias will contain a copy of aliasee).
460           if (auto *AS = dyn_cast<AliasSummary>(Summary.getSecond()))
461             Callback({AS->getAliaseeGUID(), &AS->getAliasee()}, true);
462         }
463     } else {
464       for (auto &Summaries : Index)
465         for (auto &Summary : Summaries.second.SummaryList)
466           Callback({Summaries.first, Summary.get()}, false);
467     }
468   }
469 
470   /// Calls the callback for each entry in the modulePaths StringMap that
471   /// should be written to the module path string table. This hides the details
472   /// of whether they are being pulled from the entire index or just those in a
473   /// provided ModuleToSummariesForIndex map.
474   template <typename Functor> void forEachModule(Functor Callback) {
475     if (ModuleToSummariesForIndex) {
476       for (const auto &M : *ModuleToSummariesForIndex) {
477         const auto &MPI = Index.modulePaths().find(M.first);
478         if (MPI == Index.modulePaths().end()) {
479           // This should only happen if the bitcode file was empty, in which
480           // case we shouldn't be importing (the ModuleToSummariesForIndex
481           // would only include the module we are writing and index for).
482           assert(ModuleToSummariesForIndex->size() == 1);
483           continue;
484         }
485         Callback(*MPI);
486       }
487     } else {
488       for (const auto &MPSE : Index.modulePaths())
489         Callback(MPSE);
490     }
491   }
492 
493   /// Main entry point for writing a combined index to bitcode.
494   void write();
495 
496 private:
497   void writeModStrings();
498   void writeCombinedGlobalValueSummary();
499 
500   Optional<unsigned> getValueId(GlobalValue::GUID ValGUID) {
501     auto VMI = GUIDToValueIdMap.find(ValGUID);
502     if (VMI == GUIDToValueIdMap.end())
503       return None;
504     return VMI->second;
505   }
506 
507   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
508 };
509 
510 } // end anonymous namespace
511 
512 static unsigned getEncodedCastOpcode(unsigned Opcode) {
513   switch (Opcode) {
514   default: llvm_unreachable("Unknown cast instruction!");
515   case Instruction::Trunc   : return bitc::CAST_TRUNC;
516   case Instruction::ZExt    : return bitc::CAST_ZEXT;
517   case Instruction::SExt    : return bitc::CAST_SEXT;
518   case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
519   case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
520   case Instruction::UIToFP  : return bitc::CAST_UITOFP;
521   case Instruction::SIToFP  : return bitc::CAST_SITOFP;
522   case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
523   case Instruction::FPExt   : return bitc::CAST_FPEXT;
524   case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
525   case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
526   case Instruction::BitCast : return bitc::CAST_BITCAST;
527   case Instruction::AddrSpaceCast: return bitc::CAST_ADDRSPACECAST;
528   }
529 }
530 
531 static unsigned getEncodedUnaryOpcode(unsigned Opcode) {
532   switch (Opcode) {
533   default: llvm_unreachable("Unknown binary instruction!");
534   case Instruction::FNeg: return bitc::UNOP_FNEG;
535   }
536 }
537 
538 static unsigned getEncodedBinaryOpcode(unsigned Opcode) {
539   switch (Opcode) {
540   default: llvm_unreachable("Unknown binary instruction!");
541   case Instruction::Add:
542   case Instruction::FAdd: return bitc::BINOP_ADD;
543   case Instruction::Sub:
544   case Instruction::FSub: return bitc::BINOP_SUB;
545   case Instruction::Mul:
546   case Instruction::FMul: return bitc::BINOP_MUL;
547   case Instruction::UDiv: return bitc::BINOP_UDIV;
548   case Instruction::FDiv:
549   case Instruction::SDiv: return bitc::BINOP_SDIV;
550   case Instruction::URem: return bitc::BINOP_UREM;
551   case Instruction::FRem:
552   case Instruction::SRem: return bitc::BINOP_SREM;
553   case Instruction::Shl:  return bitc::BINOP_SHL;
554   case Instruction::LShr: return bitc::BINOP_LSHR;
555   case Instruction::AShr: return bitc::BINOP_ASHR;
556   case Instruction::And:  return bitc::BINOP_AND;
557   case Instruction::Or:   return bitc::BINOP_OR;
558   case Instruction::Xor:  return bitc::BINOP_XOR;
559   }
560 }
561 
562 static unsigned getEncodedRMWOperation(AtomicRMWInst::BinOp Op) {
563   switch (Op) {
564   default: llvm_unreachable("Unknown RMW operation!");
565   case AtomicRMWInst::Xchg: return bitc::RMW_XCHG;
566   case AtomicRMWInst::Add: return bitc::RMW_ADD;
567   case AtomicRMWInst::Sub: return bitc::RMW_SUB;
568   case AtomicRMWInst::And: return bitc::RMW_AND;
569   case AtomicRMWInst::Nand: return bitc::RMW_NAND;
570   case AtomicRMWInst::Or: return bitc::RMW_OR;
571   case AtomicRMWInst::Xor: return bitc::RMW_XOR;
572   case AtomicRMWInst::Max: return bitc::RMW_MAX;
573   case AtomicRMWInst::Min: return bitc::RMW_MIN;
574   case AtomicRMWInst::UMax: return bitc::RMW_UMAX;
575   case AtomicRMWInst::UMin: return bitc::RMW_UMIN;
576   case AtomicRMWInst::FAdd: return bitc::RMW_FADD;
577   case AtomicRMWInst::FSub: return bitc::RMW_FSUB;
578   }
579 }
580 
581 static unsigned getEncodedOrdering(AtomicOrdering Ordering) {
582   switch (Ordering) {
583   case AtomicOrdering::NotAtomic: return bitc::ORDERING_NOTATOMIC;
584   case AtomicOrdering::Unordered: return bitc::ORDERING_UNORDERED;
585   case AtomicOrdering::Monotonic: return bitc::ORDERING_MONOTONIC;
586   case AtomicOrdering::Acquire: return bitc::ORDERING_ACQUIRE;
587   case AtomicOrdering::Release: return bitc::ORDERING_RELEASE;
588   case AtomicOrdering::AcquireRelease: return bitc::ORDERING_ACQREL;
589   case AtomicOrdering::SequentiallyConsistent: return bitc::ORDERING_SEQCST;
590   }
591   llvm_unreachable("Invalid ordering");
592 }
593 
594 static void writeStringRecord(BitstreamWriter &Stream, unsigned Code,
595                               StringRef Str, unsigned AbbrevToUse) {
596   SmallVector<unsigned, 64> Vals;
597 
598   // Code: [strchar x N]
599   for (char C : Str) {
600     if (AbbrevToUse && !BitCodeAbbrevOp::isChar6(C))
601       AbbrevToUse = 0;
602     Vals.push_back(C);
603   }
604 
605   // Emit the finished record.
606   Stream.EmitRecord(Code, Vals, AbbrevToUse);
607 }
608 
609 static uint64_t getAttrKindEncoding(Attribute::AttrKind Kind) {
610   switch (Kind) {
611   case Attribute::Alignment:
612     return bitc::ATTR_KIND_ALIGNMENT;
613   case Attribute::AllocAlign:
614     return bitc::ATTR_KIND_ALLOC_ALIGN;
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::DisableSanitizerInstrumentation:
632     return bitc::ATTR_KIND_DISABLE_SANITIZER_INSTRUMENTATION;
633   case Attribute::Hot:
634     return bitc::ATTR_KIND_HOT;
635   case Attribute::ElementType:
636     return bitc::ATTR_KIND_ELEMENTTYPE;
637   case Attribute::InaccessibleMemOnly:
638     return bitc::ATTR_KIND_INACCESSIBLEMEM_ONLY;
639   case Attribute::InaccessibleMemOrArgMemOnly:
640     return bitc::ATTR_KIND_INACCESSIBLEMEM_OR_ARGMEMONLY;
641   case Attribute::InlineHint:
642     return bitc::ATTR_KIND_INLINE_HINT;
643   case Attribute::InReg:
644     return bitc::ATTR_KIND_IN_REG;
645   case Attribute::JumpTable:
646     return bitc::ATTR_KIND_JUMP_TABLE;
647   case Attribute::MinSize:
648     return bitc::ATTR_KIND_MIN_SIZE;
649   case Attribute::Naked:
650     return bitc::ATTR_KIND_NAKED;
651   case Attribute::Nest:
652     return bitc::ATTR_KIND_NEST;
653   case Attribute::NoAlias:
654     return bitc::ATTR_KIND_NO_ALIAS;
655   case Attribute::NoBuiltin:
656     return bitc::ATTR_KIND_NO_BUILTIN;
657   case Attribute::NoCallback:
658     return bitc::ATTR_KIND_NO_CALLBACK;
659   case Attribute::NoCapture:
660     return bitc::ATTR_KIND_NO_CAPTURE;
661   case Attribute::NoDuplicate:
662     return bitc::ATTR_KIND_NO_DUPLICATE;
663   case Attribute::NoFree:
664     return bitc::ATTR_KIND_NOFREE;
665   case Attribute::NoImplicitFloat:
666     return bitc::ATTR_KIND_NO_IMPLICIT_FLOAT;
667   case Attribute::NoInline:
668     return bitc::ATTR_KIND_NO_INLINE;
669   case Attribute::NoRecurse:
670     return bitc::ATTR_KIND_NO_RECURSE;
671   case Attribute::NoMerge:
672     return bitc::ATTR_KIND_NO_MERGE;
673   case Attribute::NonLazyBind:
674     return bitc::ATTR_KIND_NON_LAZY_BIND;
675   case Attribute::NonNull:
676     return bitc::ATTR_KIND_NON_NULL;
677   case Attribute::Dereferenceable:
678     return bitc::ATTR_KIND_DEREFERENCEABLE;
679   case Attribute::DereferenceableOrNull:
680     return bitc::ATTR_KIND_DEREFERENCEABLE_OR_NULL;
681   case Attribute::NoRedZone:
682     return bitc::ATTR_KIND_NO_RED_ZONE;
683   case Attribute::NoReturn:
684     return bitc::ATTR_KIND_NO_RETURN;
685   case Attribute::NoSync:
686     return bitc::ATTR_KIND_NOSYNC;
687   case Attribute::NoCfCheck:
688     return bitc::ATTR_KIND_NOCF_CHECK;
689   case Attribute::NoProfile:
690     return bitc::ATTR_KIND_NO_PROFILE;
691   case Attribute::NoUnwind:
692     return bitc::ATTR_KIND_NO_UNWIND;
693   case Attribute::NoSanitizeBounds:
694     return bitc::ATTR_KIND_NO_SANITIZE_BOUNDS;
695   case Attribute::NoSanitizeCoverage:
696     return bitc::ATTR_KIND_NO_SANITIZE_COVERAGE;
697   case Attribute::NullPointerIsValid:
698     return bitc::ATTR_KIND_NULL_POINTER_IS_VALID;
699   case Attribute::OptForFuzzing:
700     return bitc::ATTR_KIND_OPT_FOR_FUZZING;
701   case Attribute::OptimizeForSize:
702     return bitc::ATTR_KIND_OPTIMIZE_FOR_SIZE;
703   case Attribute::OptimizeNone:
704     return bitc::ATTR_KIND_OPTIMIZE_NONE;
705   case Attribute::ReadNone:
706     return bitc::ATTR_KIND_READ_NONE;
707   case Attribute::ReadOnly:
708     return bitc::ATTR_KIND_READ_ONLY;
709   case Attribute::Returned:
710     return bitc::ATTR_KIND_RETURNED;
711   case Attribute::ReturnsTwice:
712     return bitc::ATTR_KIND_RETURNS_TWICE;
713   case Attribute::SExt:
714     return bitc::ATTR_KIND_S_EXT;
715   case Attribute::Speculatable:
716     return bitc::ATTR_KIND_SPECULATABLE;
717   case Attribute::StackAlignment:
718     return bitc::ATTR_KIND_STACK_ALIGNMENT;
719   case Attribute::StackProtect:
720     return bitc::ATTR_KIND_STACK_PROTECT;
721   case Attribute::StackProtectReq:
722     return bitc::ATTR_KIND_STACK_PROTECT_REQ;
723   case Attribute::StackProtectStrong:
724     return bitc::ATTR_KIND_STACK_PROTECT_STRONG;
725   case Attribute::SafeStack:
726     return bitc::ATTR_KIND_SAFESTACK;
727   case Attribute::ShadowCallStack:
728     return bitc::ATTR_KIND_SHADOWCALLSTACK;
729   case Attribute::StrictFP:
730     return bitc::ATTR_KIND_STRICT_FP;
731   case Attribute::StructRet:
732     return bitc::ATTR_KIND_STRUCT_RET;
733   case Attribute::SanitizeAddress:
734     return bitc::ATTR_KIND_SANITIZE_ADDRESS;
735   case Attribute::SanitizeHWAddress:
736     return bitc::ATTR_KIND_SANITIZE_HWADDRESS;
737   case Attribute::SanitizeThread:
738     return bitc::ATTR_KIND_SANITIZE_THREAD;
739   case Attribute::SanitizeMemory:
740     return bitc::ATTR_KIND_SANITIZE_MEMORY;
741   case Attribute::SpeculativeLoadHardening:
742     return bitc::ATTR_KIND_SPECULATIVE_LOAD_HARDENING;
743   case Attribute::SwiftError:
744     return bitc::ATTR_KIND_SWIFT_ERROR;
745   case Attribute::SwiftSelf:
746     return bitc::ATTR_KIND_SWIFT_SELF;
747   case Attribute::SwiftAsync:
748     return bitc::ATTR_KIND_SWIFT_ASYNC;
749   case Attribute::UWTable:
750     return bitc::ATTR_KIND_UW_TABLE;
751   case Attribute::VScaleRange:
752     return bitc::ATTR_KIND_VSCALE_RANGE;
753   case Attribute::WillReturn:
754     return bitc::ATTR_KIND_WILLRETURN;
755   case Attribute::WriteOnly:
756     return bitc::ATTR_KIND_WRITEONLY;
757   case Attribute::ZExt:
758     return bitc::ATTR_KIND_Z_EXT;
759   case Attribute::ImmArg:
760     return bitc::ATTR_KIND_IMMARG;
761   case Attribute::SanitizeMemTag:
762     return bitc::ATTR_KIND_SANITIZE_MEMTAG;
763   case Attribute::Preallocated:
764     return bitc::ATTR_KIND_PREALLOCATED;
765   case Attribute::NoUndef:
766     return bitc::ATTR_KIND_NOUNDEF;
767   case Attribute::ByRef:
768     return bitc::ATTR_KIND_BYREF;
769   case Attribute::MustProgress:
770     return bitc::ATTR_KIND_MUSTPROGRESS;
771   case Attribute::EndAttrKinds:
772     llvm_unreachable("Can not encode end-attribute kinds marker.");
773   case Attribute::None:
774     llvm_unreachable("Can not encode none-attribute.");
775   case Attribute::EmptyKey:
776   case Attribute::TombstoneKey:
777     llvm_unreachable("Trying to encode EmptyKey/TombstoneKey");
778   }
779 
780   llvm_unreachable("Trying to encode unknown attribute");
781 }
782 
783 void ModuleBitcodeWriter::writeAttributeGroupTable() {
784   const std::vector<ValueEnumerator::IndexAndAttrSet> &AttrGrps =
785       VE.getAttributeGroups();
786   if (AttrGrps.empty()) return;
787 
788   Stream.EnterSubblock(bitc::PARAMATTR_GROUP_BLOCK_ID, 3);
789 
790   SmallVector<uint64_t, 64> Record;
791   for (ValueEnumerator::IndexAndAttrSet Pair : AttrGrps) {
792     unsigned AttrListIndex = Pair.first;
793     AttributeSet AS = Pair.second;
794     Record.push_back(VE.getAttributeGroupID(Pair));
795     Record.push_back(AttrListIndex);
796 
797     for (Attribute Attr : AS) {
798       if (Attr.isEnumAttribute()) {
799         Record.push_back(0);
800         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
801       } else if (Attr.isIntAttribute()) {
802         Record.push_back(1);
803         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
804         Record.push_back(Attr.getValueAsInt());
805       } else if (Attr.isStringAttribute()) {
806         StringRef Kind = Attr.getKindAsString();
807         StringRef Val = Attr.getValueAsString();
808 
809         Record.push_back(Val.empty() ? 3 : 4);
810         Record.append(Kind.begin(), Kind.end());
811         Record.push_back(0);
812         if (!Val.empty()) {
813           Record.append(Val.begin(), Val.end());
814           Record.push_back(0);
815         }
816       } else {
817         assert(Attr.isTypeAttribute());
818         Type *Ty = Attr.getValueAsType();
819         Record.push_back(Ty ? 6 : 5);
820         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
821         if (Ty)
822           Record.push_back(VE.getTypeID(Attr.getValueAsType()));
823       }
824     }
825 
826     Stream.EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
827     Record.clear();
828   }
829 
830   Stream.ExitBlock();
831 }
832 
833 void ModuleBitcodeWriter::writeAttributeTable() {
834   const std::vector<AttributeList> &Attrs = VE.getAttributeLists();
835   if (Attrs.empty()) return;
836 
837   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
838 
839   SmallVector<uint64_t, 64> Record;
840   for (const AttributeList &AL : Attrs) {
841     for (unsigned i : AL.indexes()) {
842       AttributeSet AS = AL.getAttributes(i);
843       if (AS.hasAttributes())
844         Record.push_back(VE.getAttributeGroupID({i, AS}));
845     }
846 
847     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
848     Record.clear();
849   }
850 
851   Stream.ExitBlock();
852 }
853 
854 /// WriteTypeTable - Write out the type table for a module.
855 void ModuleBitcodeWriter::writeTypeTable() {
856   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
857 
858   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
859   SmallVector<uint64_t, 64> TypeVals;
860 
861   uint64_t NumBits = VE.computeBitsRequiredForTypeIndicies();
862 
863   // Abbrev for TYPE_CODE_POINTER.
864   auto Abbv = std::make_shared<BitCodeAbbrev>();
865   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
866   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
867   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
868   unsigned PtrAbbrev = Stream.EmitAbbrev(std::move(Abbv));
869 
870   // Abbrev for TYPE_CODE_OPAQUE_POINTER.
871   Abbv = std::make_shared<BitCodeAbbrev>();
872   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_OPAQUE_POINTER));
873   Abbv->Add(BitCodeAbbrevOp(0)); // Addrspace = 0
874   unsigned OpaquePtrAbbrev = Stream.EmitAbbrev(std::move(Abbv));
875 
876   // Abbrev for TYPE_CODE_FUNCTION.
877   Abbv = std::make_shared<BitCodeAbbrev>();
878   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
879   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
880   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
881   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
882   unsigned FunctionAbbrev = Stream.EmitAbbrev(std::move(Abbv));
883 
884   // Abbrev for TYPE_CODE_STRUCT_ANON.
885   Abbv = std::make_shared<BitCodeAbbrev>();
886   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
887   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
888   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
889   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
890   unsigned StructAnonAbbrev = Stream.EmitAbbrev(std::move(Abbv));
891 
892   // Abbrev for TYPE_CODE_STRUCT_NAME.
893   Abbv = std::make_shared<BitCodeAbbrev>();
894   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
895   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
896   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
897   unsigned StructNameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
898 
899   // Abbrev for TYPE_CODE_STRUCT_NAMED.
900   Abbv = std::make_shared<BitCodeAbbrev>();
901   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
902   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
903   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
904   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
905   unsigned StructNamedAbbrev = Stream.EmitAbbrev(std::move(Abbv));
906 
907   // Abbrev for TYPE_CODE_ARRAY.
908   Abbv = std::make_shared<BitCodeAbbrev>();
909   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
910   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
911   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
912   unsigned ArrayAbbrev = Stream.EmitAbbrev(std::move(Abbv));
913 
914   // Emit an entry count so the reader can reserve space.
915   TypeVals.push_back(TypeList.size());
916   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
917   TypeVals.clear();
918 
919   // Loop over all of the types, emitting each in turn.
920   for (Type *T : TypeList) {
921     int AbbrevToUse = 0;
922     unsigned Code = 0;
923 
924     switch (T->getTypeID()) {
925     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;      break;
926     case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;      break;
927     case Type::BFloatTyID:    Code = bitc::TYPE_CODE_BFLOAT;    break;
928     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;     break;
929     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE;    break;
930     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80;  break;
931     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128;     break;
932     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
933     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;     break;
934     case Type::MetadataTyID:  Code = bitc::TYPE_CODE_METADATA;  break;
935     case Type::X86_MMXTyID:   Code = bitc::TYPE_CODE_X86_MMX;   break;
936     case Type::X86_AMXTyID:   Code = bitc::TYPE_CODE_X86_AMX;   break;
937     case Type::TokenTyID:     Code = bitc::TYPE_CODE_TOKEN;     break;
938     case Type::IntegerTyID:
939       // INTEGER: [width]
940       Code = bitc::TYPE_CODE_INTEGER;
941       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
942       break;
943     case Type::PointerTyID: {
944       PointerType *PTy = cast<PointerType>(T);
945       unsigned AddressSpace = PTy->getAddressSpace();
946       if (PTy->isOpaque()) {
947         // OPAQUE_POINTER: [address space]
948         Code = bitc::TYPE_CODE_OPAQUE_POINTER;
949         TypeVals.push_back(AddressSpace);
950         if (AddressSpace == 0)
951           AbbrevToUse = OpaquePtrAbbrev;
952       } else {
953         // POINTER: [pointee type, address space]
954         Code = bitc::TYPE_CODE_POINTER;
955         TypeVals.push_back(VE.getTypeID(PTy->getNonOpaquePointerElementType()));
956         TypeVals.push_back(AddressSpace);
957         if (AddressSpace == 0)
958           AbbrevToUse = PtrAbbrev;
959       }
960       break;
961     }
962     case Type::FunctionTyID: {
963       FunctionType *FT = cast<FunctionType>(T);
964       // FUNCTION: [isvararg, retty, paramty x N]
965       Code = bitc::TYPE_CODE_FUNCTION;
966       TypeVals.push_back(FT->isVarArg());
967       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
968       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
969         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
970       AbbrevToUse = FunctionAbbrev;
971       break;
972     }
973     case Type::StructTyID: {
974       StructType *ST = cast<StructType>(T);
975       // STRUCT: [ispacked, eltty x N]
976       TypeVals.push_back(ST->isPacked());
977       // Output all of the element types.
978       for (Type *ET : ST->elements())
979         TypeVals.push_back(VE.getTypeID(ET));
980 
981       if (ST->isLiteral()) {
982         Code = bitc::TYPE_CODE_STRUCT_ANON;
983         AbbrevToUse = StructAnonAbbrev;
984       } else {
985         if (ST->isOpaque()) {
986           Code = bitc::TYPE_CODE_OPAQUE;
987         } else {
988           Code = bitc::TYPE_CODE_STRUCT_NAMED;
989           AbbrevToUse = StructNamedAbbrev;
990         }
991 
992         // Emit the name if it is present.
993         if (!ST->getName().empty())
994           writeStringRecord(Stream, bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
995                             StructNameAbbrev);
996       }
997       break;
998     }
999     case Type::ArrayTyID: {
1000       ArrayType *AT = cast<ArrayType>(T);
1001       // ARRAY: [numelts, eltty]
1002       Code = bitc::TYPE_CODE_ARRAY;
1003       TypeVals.push_back(AT->getNumElements());
1004       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
1005       AbbrevToUse = ArrayAbbrev;
1006       break;
1007     }
1008     case Type::FixedVectorTyID:
1009     case Type::ScalableVectorTyID: {
1010       VectorType *VT = cast<VectorType>(T);
1011       // VECTOR [numelts, eltty] or
1012       //        [numelts, eltty, scalable]
1013       Code = bitc::TYPE_CODE_VECTOR;
1014       TypeVals.push_back(VT->getElementCount().getKnownMinValue());
1015       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
1016       if (isa<ScalableVectorType>(VT))
1017         TypeVals.push_back(true);
1018       break;
1019     }
1020     }
1021 
1022     // Emit the finished record.
1023     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
1024     TypeVals.clear();
1025   }
1026 
1027   Stream.ExitBlock();
1028 }
1029 
1030 static unsigned getEncodedLinkage(const GlobalValue::LinkageTypes Linkage) {
1031   switch (Linkage) {
1032   case GlobalValue::ExternalLinkage:
1033     return 0;
1034   case GlobalValue::WeakAnyLinkage:
1035     return 16;
1036   case GlobalValue::AppendingLinkage:
1037     return 2;
1038   case GlobalValue::InternalLinkage:
1039     return 3;
1040   case GlobalValue::LinkOnceAnyLinkage:
1041     return 18;
1042   case GlobalValue::ExternalWeakLinkage:
1043     return 7;
1044   case GlobalValue::CommonLinkage:
1045     return 8;
1046   case GlobalValue::PrivateLinkage:
1047     return 9;
1048   case GlobalValue::WeakODRLinkage:
1049     return 17;
1050   case GlobalValue::LinkOnceODRLinkage:
1051     return 19;
1052   case GlobalValue::AvailableExternallyLinkage:
1053     return 12;
1054   }
1055   llvm_unreachable("Invalid linkage");
1056 }
1057 
1058 static unsigned getEncodedLinkage(const GlobalValue &GV) {
1059   return getEncodedLinkage(GV.getLinkage());
1060 }
1061 
1062 static uint64_t getEncodedFFlags(FunctionSummary::FFlags Flags) {
1063   uint64_t RawFlags = 0;
1064   RawFlags |= Flags.ReadNone;
1065   RawFlags |= (Flags.ReadOnly << 1);
1066   RawFlags |= (Flags.NoRecurse << 2);
1067   RawFlags |= (Flags.ReturnDoesNotAlias << 3);
1068   RawFlags |= (Flags.NoInline << 4);
1069   RawFlags |= (Flags.AlwaysInline << 5);
1070   RawFlags |= (Flags.NoUnwind << 6);
1071   RawFlags |= (Flags.MayThrow << 7);
1072   RawFlags |= (Flags.HasUnknownCall << 8);
1073   RawFlags |= (Flags.MustBeUnreachable << 9);
1074   return RawFlags;
1075 }
1076 
1077 // Decode the flags for GlobalValue in the summary. See getDecodedGVSummaryFlags
1078 // in BitcodeReader.cpp.
1079 static uint64_t getEncodedGVSummaryFlags(GlobalValueSummary::GVFlags Flags) {
1080   uint64_t RawFlags = 0;
1081 
1082   RawFlags |= Flags.NotEligibleToImport; // bool
1083   RawFlags |= (Flags.Live << 1);
1084   RawFlags |= (Flags.DSOLocal << 2);
1085   RawFlags |= (Flags.CanAutoHide << 3);
1086 
1087   // Linkage don't need to be remapped at that time for the summary. Any future
1088   // change to the getEncodedLinkage() function will need to be taken into
1089   // account here as well.
1090   RawFlags = (RawFlags << 4) | Flags.Linkage; // 4 bits
1091 
1092   RawFlags |= (Flags.Visibility << 8); // 2 bits
1093 
1094   return RawFlags;
1095 }
1096 
1097 static uint64_t getEncodedGVarFlags(GlobalVarSummary::GVarFlags Flags) {
1098   uint64_t RawFlags = Flags.MaybeReadOnly | (Flags.MaybeWriteOnly << 1) |
1099                       (Flags.Constant << 2) | Flags.VCallVisibility << 3;
1100   return RawFlags;
1101 }
1102 
1103 static unsigned getEncodedVisibility(const GlobalValue &GV) {
1104   switch (GV.getVisibility()) {
1105   case GlobalValue::DefaultVisibility:   return 0;
1106   case GlobalValue::HiddenVisibility:    return 1;
1107   case GlobalValue::ProtectedVisibility: return 2;
1108   }
1109   llvm_unreachable("Invalid visibility");
1110 }
1111 
1112 static unsigned getEncodedDLLStorageClass(const GlobalValue &GV) {
1113   switch (GV.getDLLStorageClass()) {
1114   case GlobalValue::DefaultStorageClass:   return 0;
1115   case GlobalValue::DLLImportStorageClass: return 1;
1116   case GlobalValue::DLLExportStorageClass: return 2;
1117   }
1118   llvm_unreachable("Invalid DLL storage class");
1119 }
1120 
1121 static unsigned getEncodedThreadLocalMode(const GlobalValue &GV) {
1122   switch (GV.getThreadLocalMode()) {
1123     case GlobalVariable::NotThreadLocal:         return 0;
1124     case GlobalVariable::GeneralDynamicTLSModel: return 1;
1125     case GlobalVariable::LocalDynamicTLSModel:   return 2;
1126     case GlobalVariable::InitialExecTLSModel:    return 3;
1127     case GlobalVariable::LocalExecTLSModel:      return 4;
1128   }
1129   llvm_unreachable("Invalid TLS model");
1130 }
1131 
1132 static unsigned getEncodedComdatSelectionKind(const Comdat &C) {
1133   switch (C.getSelectionKind()) {
1134   case Comdat::Any:
1135     return bitc::COMDAT_SELECTION_KIND_ANY;
1136   case Comdat::ExactMatch:
1137     return bitc::COMDAT_SELECTION_KIND_EXACT_MATCH;
1138   case Comdat::Largest:
1139     return bitc::COMDAT_SELECTION_KIND_LARGEST;
1140   case Comdat::NoDeduplicate:
1141     return bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES;
1142   case Comdat::SameSize:
1143     return bitc::COMDAT_SELECTION_KIND_SAME_SIZE;
1144   }
1145   llvm_unreachable("Invalid selection kind");
1146 }
1147 
1148 static unsigned getEncodedUnnamedAddr(const GlobalValue &GV) {
1149   switch (GV.getUnnamedAddr()) {
1150   case GlobalValue::UnnamedAddr::None:   return 0;
1151   case GlobalValue::UnnamedAddr::Local:  return 2;
1152   case GlobalValue::UnnamedAddr::Global: return 1;
1153   }
1154   llvm_unreachable("Invalid unnamed_addr");
1155 }
1156 
1157 size_t ModuleBitcodeWriter::addToStrtab(StringRef Str) {
1158   if (GenerateHash)
1159     Hasher.update(Str);
1160   return StrtabBuilder.add(Str);
1161 }
1162 
1163 void ModuleBitcodeWriter::writeComdats() {
1164   SmallVector<unsigned, 64> Vals;
1165   for (const Comdat *C : VE.getComdats()) {
1166     // COMDAT: [strtab offset, strtab size, selection_kind]
1167     Vals.push_back(addToStrtab(C->getName()));
1168     Vals.push_back(C->getName().size());
1169     Vals.push_back(getEncodedComdatSelectionKind(*C));
1170     Stream.EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
1171     Vals.clear();
1172   }
1173 }
1174 
1175 /// Write a record that will eventually hold the word offset of the
1176 /// module-level VST. For now the offset is 0, which will be backpatched
1177 /// after the real VST is written. Saves the bit offset to backpatch.
1178 void ModuleBitcodeWriter::writeValueSymbolTableForwardDecl() {
1179   // Write a placeholder value in for the offset of the real VST,
1180   // which is written after the function blocks so that it can include
1181   // the offset of each function. The placeholder offset will be
1182   // updated when the real VST is written.
1183   auto Abbv = std::make_shared<BitCodeAbbrev>();
1184   Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_VSTOFFSET));
1185   // Blocks are 32-bit aligned, so we can use a 32-bit word offset to
1186   // hold the real VST offset. Must use fixed instead of VBR as we don't
1187   // know how many VBR chunks to reserve ahead of time.
1188   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
1189   unsigned VSTOffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1190 
1191   // Emit the placeholder
1192   uint64_t Vals[] = {bitc::MODULE_CODE_VSTOFFSET, 0};
1193   Stream.EmitRecordWithAbbrev(VSTOffsetAbbrev, Vals);
1194 
1195   // Compute and save the bit offset to the placeholder, which will be
1196   // patched when the real VST is written. We can simply subtract the 32-bit
1197   // fixed size from the current bit number to get the location to backpatch.
1198   VSTOffsetPlaceholder = Stream.GetCurrentBitNo() - 32;
1199 }
1200 
1201 enum StringEncoding { SE_Char6, SE_Fixed7, SE_Fixed8 };
1202 
1203 /// Determine the encoding to use for the given string name and length.
1204 static StringEncoding getStringEncoding(StringRef Str) {
1205   bool isChar6 = true;
1206   for (char C : Str) {
1207     if (isChar6)
1208       isChar6 = BitCodeAbbrevOp::isChar6(C);
1209     if ((unsigned char)C & 128)
1210       // don't bother scanning the rest.
1211       return SE_Fixed8;
1212   }
1213   if (isChar6)
1214     return SE_Char6;
1215   return SE_Fixed7;
1216 }
1217 
1218 /// Emit top-level description of module, including target triple, inline asm,
1219 /// descriptors for global variables, and function prototype info.
1220 /// Returns the bit offset to backpatch with the location of the real VST.
1221 void ModuleBitcodeWriter::writeModuleInfo() {
1222   // Emit various pieces of data attached to a module.
1223   if (!M.getTargetTriple().empty())
1224     writeStringRecord(Stream, bitc::MODULE_CODE_TRIPLE, M.getTargetTriple(),
1225                       0 /*TODO*/);
1226   const std::string &DL = M.getDataLayoutStr();
1227   if (!DL.empty())
1228     writeStringRecord(Stream, bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/);
1229   if (!M.getModuleInlineAsm().empty())
1230     writeStringRecord(Stream, bitc::MODULE_CODE_ASM, M.getModuleInlineAsm(),
1231                       0 /*TODO*/);
1232 
1233   // Emit information about sections and GC, computing how many there are. Also
1234   // compute the maximum alignment value.
1235   std::map<std::string, unsigned> SectionMap;
1236   std::map<std::string, unsigned> GCMap;
1237   MaybeAlign MaxAlignment;
1238   unsigned MaxGlobalType = 0;
1239   const auto UpdateMaxAlignment = [&MaxAlignment](const MaybeAlign A) {
1240     if (A)
1241       MaxAlignment = !MaxAlignment ? *A : std::max(*MaxAlignment, *A);
1242   };
1243   for (const GlobalVariable &GV : M.globals()) {
1244     UpdateMaxAlignment(GV.getAlign());
1245     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getValueType()));
1246     if (GV.hasSection()) {
1247       // Give section names unique ID's.
1248       unsigned &Entry = SectionMap[std::string(GV.getSection())];
1249       if (!Entry) {
1250         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
1251                           0 /*TODO*/);
1252         Entry = SectionMap.size();
1253       }
1254     }
1255   }
1256   for (const Function &F : M) {
1257     UpdateMaxAlignment(F.getAlign());
1258     if (F.hasSection()) {
1259       // Give section names unique ID's.
1260       unsigned &Entry = SectionMap[std::string(F.getSection())];
1261       if (!Entry) {
1262         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
1263                           0 /*TODO*/);
1264         Entry = SectionMap.size();
1265       }
1266     }
1267     if (F.hasGC()) {
1268       // Same for GC names.
1269       unsigned &Entry = GCMap[F.getGC()];
1270       if (!Entry) {
1271         writeStringRecord(Stream, bitc::MODULE_CODE_GCNAME, F.getGC(),
1272                           0 /*TODO*/);
1273         Entry = GCMap.size();
1274       }
1275     }
1276   }
1277 
1278   // Emit abbrev for globals, now that we know # sections and max alignment.
1279   unsigned SimpleGVarAbbrev = 0;
1280   if (!M.global_empty()) {
1281     // Add an abbrev for common globals with no visibility or thread localness.
1282     auto Abbv = std::make_shared<BitCodeAbbrev>();
1283     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
1284     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1285     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1286     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1287                               Log2_32_Ceil(MaxGlobalType+1)));
1288     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddrSpace << 2
1289                                                            //| explicitType << 1
1290                                                            //| constant
1291     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Initializer.
1292     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // Linkage.
1293     if (!MaxAlignment)                                     // Alignment.
1294       Abbv->Add(BitCodeAbbrevOp(0));
1295     else {
1296       unsigned MaxEncAlignment = getEncodedAlign(MaxAlignment);
1297       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1298                                Log2_32_Ceil(MaxEncAlignment+1)));
1299     }
1300     if (SectionMap.empty())                                    // Section.
1301       Abbv->Add(BitCodeAbbrevOp(0));
1302     else
1303       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1304                                Log2_32_Ceil(SectionMap.size()+1)));
1305     // Don't bother emitting vis + thread local.
1306     SimpleGVarAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1307   }
1308 
1309   SmallVector<unsigned, 64> Vals;
1310   // Emit the module's source file name.
1311   {
1312     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
1313     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
1314     if (Bits == SE_Char6)
1315       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
1316     else if (Bits == SE_Fixed7)
1317       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
1318 
1319     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
1320     auto Abbv = std::make_shared<BitCodeAbbrev>();
1321     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
1322     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1323     Abbv->Add(AbbrevOpToUse);
1324     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1325 
1326     for (const auto P : M.getSourceFileName())
1327       Vals.push_back((unsigned char)P);
1328 
1329     // Emit the finished record.
1330     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
1331     Vals.clear();
1332   }
1333 
1334   // Emit the global variable information.
1335   for (const GlobalVariable &GV : M.globals()) {
1336     unsigned AbbrevToUse = 0;
1337 
1338     // GLOBALVAR: [strtab offset, strtab size, type, isconst, initid,
1339     //             linkage, alignment, section, visibility, threadlocal,
1340     //             unnamed_addr, externally_initialized, dllstorageclass,
1341     //             comdat, attributes, DSO_Local]
1342     Vals.push_back(addToStrtab(GV.getName()));
1343     Vals.push_back(GV.getName().size());
1344     Vals.push_back(VE.getTypeID(GV.getValueType()));
1345     Vals.push_back(GV.getType()->getAddressSpace() << 2 | 2 | GV.isConstant());
1346     Vals.push_back(GV.isDeclaration() ? 0 :
1347                    (VE.getValueID(GV.getInitializer()) + 1));
1348     Vals.push_back(getEncodedLinkage(GV));
1349     Vals.push_back(getEncodedAlign(GV.getAlign()));
1350     Vals.push_back(GV.hasSection() ? SectionMap[std::string(GV.getSection())]
1351                                    : 0);
1352     if (GV.isThreadLocal() ||
1353         GV.getVisibility() != GlobalValue::DefaultVisibility ||
1354         GV.getUnnamedAddr() != GlobalValue::UnnamedAddr::None ||
1355         GV.isExternallyInitialized() ||
1356         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
1357         GV.hasComdat() ||
1358         GV.hasAttributes() ||
1359         GV.isDSOLocal() ||
1360         GV.hasPartition()) {
1361       Vals.push_back(getEncodedVisibility(GV));
1362       Vals.push_back(getEncodedThreadLocalMode(GV));
1363       Vals.push_back(getEncodedUnnamedAddr(GV));
1364       Vals.push_back(GV.isExternallyInitialized());
1365       Vals.push_back(getEncodedDLLStorageClass(GV));
1366       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
1367 
1368       auto AL = GV.getAttributesAsList(AttributeList::FunctionIndex);
1369       Vals.push_back(VE.getAttributeListID(AL));
1370 
1371       Vals.push_back(GV.isDSOLocal());
1372       Vals.push_back(addToStrtab(GV.getPartition()));
1373       Vals.push_back(GV.getPartition().size());
1374     } else {
1375       AbbrevToUse = SimpleGVarAbbrev;
1376     }
1377 
1378     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
1379     Vals.clear();
1380   }
1381 
1382   // Emit the function proto information.
1383   for (const Function &F : M) {
1384     // FUNCTION:  [strtab offset, strtab size, type, callingconv, isproto,
1385     //             linkage, paramattrs, alignment, section, visibility, gc,
1386     //             unnamed_addr, prologuedata, dllstorageclass, comdat,
1387     //             prefixdata, personalityfn, DSO_Local, addrspace]
1388     Vals.push_back(addToStrtab(F.getName()));
1389     Vals.push_back(F.getName().size());
1390     Vals.push_back(VE.getTypeID(F.getFunctionType()));
1391     Vals.push_back(F.getCallingConv());
1392     Vals.push_back(F.isDeclaration());
1393     Vals.push_back(getEncodedLinkage(F));
1394     Vals.push_back(VE.getAttributeListID(F.getAttributes()));
1395     Vals.push_back(getEncodedAlign(F.getAlign()));
1396     Vals.push_back(F.hasSection() ? SectionMap[std::string(F.getSection())]
1397                                   : 0);
1398     Vals.push_back(getEncodedVisibility(F));
1399     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
1400     Vals.push_back(getEncodedUnnamedAddr(F));
1401     Vals.push_back(F.hasPrologueData() ? (VE.getValueID(F.getPrologueData()) + 1)
1402                                        : 0);
1403     Vals.push_back(getEncodedDLLStorageClass(F));
1404     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
1405     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
1406                                      : 0);
1407     Vals.push_back(
1408         F.hasPersonalityFn() ? (VE.getValueID(F.getPersonalityFn()) + 1) : 0);
1409 
1410     Vals.push_back(F.isDSOLocal());
1411     Vals.push_back(F.getAddressSpace());
1412     Vals.push_back(addToStrtab(F.getPartition()));
1413     Vals.push_back(F.getPartition().size());
1414 
1415     unsigned AbbrevToUse = 0;
1416     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
1417     Vals.clear();
1418   }
1419 
1420   // Emit the alias information.
1421   for (const GlobalAlias &A : M.aliases()) {
1422     // ALIAS: [strtab offset, strtab size, alias type, aliasee val#, linkage,
1423     //         visibility, dllstorageclass, threadlocal, unnamed_addr,
1424     //         DSO_Local]
1425     Vals.push_back(addToStrtab(A.getName()));
1426     Vals.push_back(A.getName().size());
1427     Vals.push_back(VE.getTypeID(A.getValueType()));
1428     Vals.push_back(A.getType()->getAddressSpace());
1429     Vals.push_back(VE.getValueID(A.getAliasee()));
1430     Vals.push_back(getEncodedLinkage(A));
1431     Vals.push_back(getEncodedVisibility(A));
1432     Vals.push_back(getEncodedDLLStorageClass(A));
1433     Vals.push_back(getEncodedThreadLocalMode(A));
1434     Vals.push_back(getEncodedUnnamedAddr(A));
1435     Vals.push_back(A.isDSOLocal());
1436     Vals.push_back(addToStrtab(A.getPartition()));
1437     Vals.push_back(A.getPartition().size());
1438 
1439     unsigned AbbrevToUse = 0;
1440     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
1441     Vals.clear();
1442   }
1443 
1444   // Emit the ifunc information.
1445   for (const GlobalIFunc &I : M.ifuncs()) {
1446     // IFUNC: [strtab offset, strtab size, ifunc type, address space, resolver
1447     //         val#, linkage, visibility, DSO_Local]
1448     Vals.push_back(addToStrtab(I.getName()));
1449     Vals.push_back(I.getName().size());
1450     Vals.push_back(VE.getTypeID(I.getValueType()));
1451     Vals.push_back(I.getType()->getAddressSpace());
1452     Vals.push_back(VE.getValueID(I.getResolver()));
1453     Vals.push_back(getEncodedLinkage(I));
1454     Vals.push_back(getEncodedVisibility(I));
1455     Vals.push_back(I.isDSOLocal());
1456     Vals.push_back(addToStrtab(I.getPartition()));
1457     Vals.push_back(I.getPartition().size());
1458     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
1459     Vals.clear();
1460   }
1461 
1462   writeValueSymbolTableForwardDecl();
1463 }
1464 
1465 static uint64_t getOptimizationFlags(const Value *V) {
1466   uint64_t Flags = 0;
1467 
1468   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
1469     if (OBO->hasNoSignedWrap())
1470       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
1471     if (OBO->hasNoUnsignedWrap())
1472       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
1473   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
1474     if (PEO->isExact())
1475       Flags |= 1 << bitc::PEO_EXACT;
1476   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
1477     if (FPMO->hasAllowReassoc())
1478       Flags |= bitc::AllowReassoc;
1479     if (FPMO->hasNoNaNs())
1480       Flags |= bitc::NoNaNs;
1481     if (FPMO->hasNoInfs())
1482       Flags |= bitc::NoInfs;
1483     if (FPMO->hasNoSignedZeros())
1484       Flags |= bitc::NoSignedZeros;
1485     if (FPMO->hasAllowReciprocal())
1486       Flags |= bitc::AllowReciprocal;
1487     if (FPMO->hasAllowContract())
1488       Flags |= bitc::AllowContract;
1489     if (FPMO->hasApproxFunc())
1490       Flags |= bitc::ApproxFunc;
1491   }
1492 
1493   return Flags;
1494 }
1495 
1496 void ModuleBitcodeWriter::writeValueAsMetadata(
1497     const ValueAsMetadata *MD, SmallVectorImpl<uint64_t> &Record) {
1498   // Mimic an MDNode with a value as one operand.
1499   Value *V = MD->getValue();
1500   Record.push_back(VE.getTypeID(V->getType()));
1501   Record.push_back(VE.getValueID(V));
1502   Stream.EmitRecord(bitc::METADATA_VALUE, Record, 0);
1503   Record.clear();
1504 }
1505 
1506 void ModuleBitcodeWriter::writeMDTuple(const MDTuple *N,
1507                                        SmallVectorImpl<uint64_t> &Record,
1508                                        unsigned Abbrev) {
1509   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
1510     Metadata *MD = N->getOperand(i);
1511     assert(!(MD && isa<LocalAsMetadata>(MD)) &&
1512            "Unexpected function-local metadata");
1513     Record.push_back(VE.getMetadataOrNullID(MD));
1514   }
1515   Stream.EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
1516                                     : bitc::METADATA_NODE,
1517                     Record, Abbrev);
1518   Record.clear();
1519 }
1520 
1521 unsigned ModuleBitcodeWriter::createDILocationAbbrev() {
1522   // Assume the column is usually under 128, and always output the inlined-at
1523   // location (it's never more expensive than building an array size 1).
1524   auto Abbv = std::make_shared<BitCodeAbbrev>();
1525   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
1526   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1527   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1528   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1529   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1530   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1531   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1532   return Stream.EmitAbbrev(std::move(Abbv));
1533 }
1534 
1535 void ModuleBitcodeWriter::writeDILocation(const DILocation *N,
1536                                           SmallVectorImpl<uint64_t> &Record,
1537                                           unsigned &Abbrev) {
1538   if (!Abbrev)
1539     Abbrev = createDILocationAbbrev();
1540 
1541   Record.push_back(N->isDistinct());
1542   Record.push_back(N->getLine());
1543   Record.push_back(N->getColumn());
1544   Record.push_back(VE.getMetadataID(N->getScope()));
1545   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
1546   Record.push_back(N->isImplicitCode());
1547 
1548   Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
1549   Record.clear();
1550 }
1551 
1552 unsigned ModuleBitcodeWriter::createGenericDINodeAbbrev() {
1553   // Assume the column is usually under 128, and always output the inlined-at
1554   // location (it's never more expensive than building an array size 1).
1555   auto Abbv = std::make_shared<BitCodeAbbrev>();
1556   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
1557   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1558   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1559   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1560   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1561   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1562   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1563   return Stream.EmitAbbrev(std::move(Abbv));
1564 }
1565 
1566 void ModuleBitcodeWriter::writeGenericDINode(const GenericDINode *N,
1567                                              SmallVectorImpl<uint64_t> &Record,
1568                                              unsigned &Abbrev) {
1569   if (!Abbrev)
1570     Abbrev = createGenericDINodeAbbrev();
1571 
1572   Record.push_back(N->isDistinct());
1573   Record.push_back(N->getTag());
1574   Record.push_back(0); // Per-tag version field; unused for now.
1575 
1576   for (auto &I : N->operands())
1577     Record.push_back(VE.getMetadataOrNullID(I));
1578 
1579   Stream.EmitRecord(bitc::METADATA_GENERIC_DEBUG, Record, Abbrev);
1580   Record.clear();
1581 }
1582 
1583 void ModuleBitcodeWriter::writeDISubrange(const DISubrange *N,
1584                                           SmallVectorImpl<uint64_t> &Record,
1585                                           unsigned Abbrev) {
1586   const uint64_t Version = 2 << 1;
1587   Record.push_back((uint64_t)N->isDistinct() | Version);
1588   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1589   Record.push_back(VE.getMetadataOrNullID(N->getRawLowerBound()));
1590   Record.push_back(VE.getMetadataOrNullID(N->getRawUpperBound()));
1591   Record.push_back(VE.getMetadataOrNullID(N->getRawStride()));
1592 
1593   Stream.EmitRecord(bitc::METADATA_SUBRANGE, Record, Abbrev);
1594   Record.clear();
1595 }
1596 
1597 void ModuleBitcodeWriter::writeDIGenericSubrange(
1598     const DIGenericSubrange *N, SmallVectorImpl<uint64_t> &Record,
1599     unsigned Abbrev) {
1600   Record.push_back((uint64_t)N->isDistinct());
1601   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1602   Record.push_back(VE.getMetadataOrNullID(N->getRawLowerBound()));
1603   Record.push_back(VE.getMetadataOrNullID(N->getRawUpperBound()));
1604   Record.push_back(VE.getMetadataOrNullID(N->getRawStride()));
1605 
1606   Stream.EmitRecord(bitc::METADATA_GENERIC_SUBRANGE, Record, Abbrev);
1607   Record.clear();
1608 }
1609 
1610 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
1611   if ((int64_t)V >= 0)
1612     Vals.push_back(V << 1);
1613   else
1614     Vals.push_back((-V << 1) | 1);
1615 }
1616 
1617 static void emitWideAPInt(SmallVectorImpl<uint64_t> &Vals, const APInt &A) {
1618   // We have an arbitrary precision integer value to write whose
1619   // bit width is > 64. However, in canonical unsigned integer
1620   // format it is likely that the high bits are going to be zero.
1621   // So, we only write the number of active words.
1622   unsigned NumWords = A.getActiveWords();
1623   const uint64_t *RawData = A.getRawData();
1624   for (unsigned i = 0; i < NumWords; i++)
1625     emitSignedInt64(Vals, RawData[i]);
1626 }
1627 
1628 void ModuleBitcodeWriter::writeDIEnumerator(const DIEnumerator *N,
1629                                             SmallVectorImpl<uint64_t> &Record,
1630                                             unsigned Abbrev) {
1631   const uint64_t IsBigInt = 1 << 2;
1632   Record.push_back(IsBigInt | (N->isUnsigned() << 1) | N->isDistinct());
1633   Record.push_back(N->getValue().getBitWidth());
1634   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1635   emitWideAPInt(Record, N->getValue());
1636 
1637   Stream.EmitRecord(bitc::METADATA_ENUMERATOR, Record, Abbrev);
1638   Record.clear();
1639 }
1640 
1641 void ModuleBitcodeWriter::writeDIBasicType(const DIBasicType *N,
1642                                            SmallVectorImpl<uint64_t> &Record,
1643                                            unsigned Abbrev) {
1644   Record.push_back(N->isDistinct());
1645   Record.push_back(N->getTag());
1646   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1647   Record.push_back(N->getSizeInBits());
1648   Record.push_back(N->getAlignInBits());
1649   Record.push_back(N->getEncoding());
1650   Record.push_back(N->getFlags());
1651 
1652   Stream.EmitRecord(bitc::METADATA_BASIC_TYPE, Record, Abbrev);
1653   Record.clear();
1654 }
1655 
1656 void ModuleBitcodeWriter::writeDIStringType(const DIStringType *N,
1657                                             SmallVectorImpl<uint64_t> &Record,
1658                                             unsigned Abbrev) {
1659   Record.push_back(N->isDistinct());
1660   Record.push_back(N->getTag());
1661   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1662   Record.push_back(VE.getMetadataOrNullID(N->getStringLength()));
1663   Record.push_back(VE.getMetadataOrNullID(N->getStringLengthExp()));
1664   Record.push_back(VE.getMetadataOrNullID(N->getStringLocationExp()));
1665   Record.push_back(N->getSizeInBits());
1666   Record.push_back(N->getAlignInBits());
1667   Record.push_back(N->getEncoding());
1668 
1669   Stream.EmitRecord(bitc::METADATA_STRING_TYPE, Record, Abbrev);
1670   Record.clear();
1671 }
1672 
1673 void ModuleBitcodeWriter::writeDIDerivedType(const DIDerivedType *N,
1674                                              SmallVectorImpl<uint64_t> &Record,
1675                                              unsigned Abbrev) {
1676   Record.push_back(N->isDistinct());
1677   Record.push_back(N->getTag());
1678   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1679   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1680   Record.push_back(N->getLine());
1681   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1682   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1683   Record.push_back(N->getSizeInBits());
1684   Record.push_back(N->getAlignInBits());
1685   Record.push_back(N->getOffsetInBits());
1686   Record.push_back(N->getFlags());
1687   Record.push_back(VE.getMetadataOrNullID(N->getExtraData()));
1688 
1689   // DWARF address space is encoded as N->getDWARFAddressSpace() + 1. 0 means
1690   // that there is no DWARF address space associated with DIDerivedType.
1691   if (const auto &DWARFAddressSpace = N->getDWARFAddressSpace())
1692     Record.push_back(*DWARFAddressSpace + 1);
1693   else
1694     Record.push_back(0);
1695 
1696   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1697 
1698   Stream.EmitRecord(bitc::METADATA_DERIVED_TYPE, Record, Abbrev);
1699   Record.clear();
1700 }
1701 
1702 void ModuleBitcodeWriter::writeDICompositeType(
1703     const DICompositeType *N, SmallVectorImpl<uint64_t> &Record,
1704     unsigned Abbrev) {
1705   const unsigned IsNotUsedInOldTypeRef = 0x2;
1706   Record.push_back(IsNotUsedInOldTypeRef | (unsigned)N->isDistinct());
1707   Record.push_back(N->getTag());
1708   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1709   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1710   Record.push_back(N->getLine());
1711   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1712   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1713   Record.push_back(N->getSizeInBits());
1714   Record.push_back(N->getAlignInBits());
1715   Record.push_back(N->getOffsetInBits());
1716   Record.push_back(N->getFlags());
1717   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1718   Record.push_back(N->getRuntimeLang());
1719   Record.push_back(VE.getMetadataOrNullID(N->getVTableHolder()));
1720   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1721   Record.push_back(VE.getMetadataOrNullID(N->getRawIdentifier()));
1722   Record.push_back(VE.getMetadataOrNullID(N->getDiscriminator()));
1723   Record.push_back(VE.getMetadataOrNullID(N->getRawDataLocation()));
1724   Record.push_back(VE.getMetadataOrNullID(N->getRawAssociated()));
1725   Record.push_back(VE.getMetadataOrNullID(N->getRawAllocated()));
1726   Record.push_back(VE.getMetadataOrNullID(N->getRawRank()));
1727   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1728 
1729   Stream.EmitRecord(bitc::METADATA_COMPOSITE_TYPE, Record, Abbrev);
1730   Record.clear();
1731 }
1732 
1733 void ModuleBitcodeWriter::writeDISubroutineType(
1734     const DISubroutineType *N, SmallVectorImpl<uint64_t> &Record,
1735     unsigned Abbrev) {
1736   const unsigned HasNoOldTypeRefs = 0x2;
1737   Record.push_back(HasNoOldTypeRefs | (unsigned)N->isDistinct());
1738   Record.push_back(N->getFlags());
1739   Record.push_back(VE.getMetadataOrNullID(N->getTypeArray().get()));
1740   Record.push_back(N->getCC());
1741 
1742   Stream.EmitRecord(bitc::METADATA_SUBROUTINE_TYPE, Record, Abbrev);
1743   Record.clear();
1744 }
1745 
1746 void ModuleBitcodeWriter::writeDIFile(const DIFile *N,
1747                                       SmallVectorImpl<uint64_t> &Record,
1748                                       unsigned Abbrev) {
1749   Record.push_back(N->isDistinct());
1750   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
1751   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
1752   if (N->getRawChecksum()) {
1753     Record.push_back(N->getRawChecksum()->Kind);
1754     Record.push_back(VE.getMetadataOrNullID(N->getRawChecksum()->Value));
1755   } else {
1756     // Maintain backwards compatibility with the old internal representation of
1757     // CSK_None in ChecksumKind by writing nulls here when Checksum is None.
1758     Record.push_back(0);
1759     Record.push_back(VE.getMetadataOrNullID(nullptr));
1760   }
1761   auto Source = N->getRawSource();
1762   if (Source)
1763     Record.push_back(VE.getMetadataOrNullID(*Source));
1764 
1765   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
1766   Record.clear();
1767 }
1768 
1769 void ModuleBitcodeWriter::writeDICompileUnit(const DICompileUnit *N,
1770                                              SmallVectorImpl<uint64_t> &Record,
1771                                              unsigned Abbrev) {
1772   assert(N->isDistinct() && "Expected distinct compile units");
1773   Record.push_back(/* IsDistinct */ true);
1774   Record.push_back(N->getSourceLanguage());
1775   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1776   Record.push_back(VE.getMetadataOrNullID(N->getRawProducer()));
1777   Record.push_back(N->isOptimized());
1778   Record.push_back(VE.getMetadataOrNullID(N->getRawFlags()));
1779   Record.push_back(N->getRuntimeVersion());
1780   Record.push_back(VE.getMetadataOrNullID(N->getRawSplitDebugFilename()));
1781   Record.push_back(N->getEmissionKind());
1782   Record.push_back(VE.getMetadataOrNullID(N->getEnumTypes().get()));
1783   Record.push_back(VE.getMetadataOrNullID(N->getRetainedTypes().get()));
1784   Record.push_back(/* subprograms */ 0);
1785   Record.push_back(VE.getMetadataOrNullID(N->getGlobalVariables().get()));
1786   Record.push_back(VE.getMetadataOrNullID(N->getImportedEntities().get()));
1787   Record.push_back(N->getDWOId());
1788   Record.push_back(VE.getMetadataOrNullID(N->getMacros().get()));
1789   Record.push_back(N->getSplitDebugInlining());
1790   Record.push_back(N->getDebugInfoForProfiling());
1791   Record.push_back((unsigned)N->getNameTableKind());
1792   Record.push_back(N->getRangesBaseAddress());
1793   Record.push_back(VE.getMetadataOrNullID(N->getRawSysRoot()));
1794   Record.push_back(VE.getMetadataOrNullID(N->getRawSDK()));
1795 
1796   Stream.EmitRecord(bitc::METADATA_COMPILE_UNIT, Record, Abbrev);
1797   Record.clear();
1798 }
1799 
1800 void ModuleBitcodeWriter::writeDISubprogram(const DISubprogram *N,
1801                                             SmallVectorImpl<uint64_t> &Record,
1802                                             unsigned Abbrev) {
1803   const uint64_t HasUnitFlag = 1 << 1;
1804   const uint64_t HasSPFlagsFlag = 1 << 2;
1805   Record.push_back(uint64_t(N->isDistinct()) | HasUnitFlag | HasSPFlagsFlag);
1806   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1807   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1808   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1809   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1810   Record.push_back(N->getLine());
1811   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1812   Record.push_back(N->getScopeLine());
1813   Record.push_back(VE.getMetadataOrNullID(N->getContainingType()));
1814   Record.push_back(N->getSPFlags());
1815   Record.push_back(N->getVirtualIndex());
1816   Record.push_back(N->getFlags());
1817   Record.push_back(VE.getMetadataOrNullID(N->getRawUnit()));
1818   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1819   Record.push_back(VE.getMetadataOrNullID(N->getDeclaration()));
1820   Record.push_back(VE.getMetadataOrNullID(N->getRetainedNodes().get()));
1821   Record.push_back(N->getThisAdjustment());
1822   Record.push_back(VE.getMetadataOrNullID(N->getThrownTypes().get()));
1823   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1824 
1825   Stream.EmitRecord(bitc::METADATA_SUBPROGRAM, Record, Abbrev);
1826   Record.clear();
1827 }
1828 
1829 void ModuleBitcodeWriter::writeDILexicalBlock(const DILexicalBlock *N,
1830                                               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->getLine());
1836   Record.push_back(N->getColumn());
1837 
1838   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK, Record, Abbrev);
1839   Record.clear();
1840 }
1841 
1842 void ModuleBitcodeWriter::writeDILexicalBlockFile(
1843     const DILexicalBlockFile *N, SmallVectorImpl<uint64_t> &Record,
1844     unsigned Abbrev) {
1845   Record.push_back(N->isDistinct());
1846   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1847   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1848   Record.push_back(N->getDiscriminator());
1849 
1850   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK_FILE, Record, Abbrev);
1851   Record.clear();
1852 }
1853 
1854 void ModuleBitcodeWriter::writeDICommonBlock(const DICommonBlock *N,
1855                                              SmallVectorImpl<uint64_t> &Record,
1856                                              unsigned Abbrev) {
1857   Record.push_back(N->isDistinct());
1858   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1859   Record.push_back(VE.getMetadataOrNullID(N->getDecl()));
1860   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1861   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1862   Record.push_back(N->getLineNo());
1863 
1864   Stream.EmitRecord(bitc::METADATA_COMMON_BLOCK, Record, Abbrev);
1865   Record.clear();
1866 }
1867 
1868 void ModuleBitcodeWriter::writeDINamespace(const DINamespace *N,
1869                                            SmallVectorImpl<uint64_t> &Record,
1870                                            unsigned Abbrev) {
1871   Record.push_back(N->isDistinct() | N->getExportSymbols() << 1);
1872   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1873   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1874 
1875   Stream.EmitRecord(bitc::METADATA_NAMESPACE, Record, Abbrev);
1876   Record.clear();
1877 }
1878 
1879 void ModuleBitcodeWriter::writeDIMacro(const DIMacro *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->getRawName()));
1886   Record.push_back(VE.getMetadataOrNullID(N->getRawValue()));
1887 
1888   Stream.EmitRecord(bitc::METADATA_MACRO, Record, Abbrev);
1889   Record.clear();
1890 }
1891 
1892 void ModuleBitcodeWriter::writeDIMacroFile(const DIMacroFile *N,
1893                                            SmallVectorImpl<uint64_t> &Record,
1894                                            unsigned Abbrev) {
1895   Record.push_back(N->isDistinct());
1896   Record.push_back(N->getMacinfoType());
1897   Record.push_back(N->getLine());
1898   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1899   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1900 
1901   Stream.EmitRecord(bitc::METADATA_MACRO_FILE, Record, Abbrev);
1902   Record.clear();
1903 }
1904 
1905 void ModuleBitcodeWriter::writeDIArgList(const DIArgList *N,
1906                                          SmallVectorImpl<uint64_t> &Record,
1907                                          unsigned Abbrev) {
1908   Record.reserve(N->getArgs().size());
1909   for (ValueAsMetadata *MD : N->getArgs())
1910     Record.push_back(VE.getMetadataID(MD));
1911 
1912   Stream.EmitRecord(bitc::METADATA_ARG_LIST, Record, Abbrev);
1913   Record.clear();
1914 }
1915 
1916 void ModuleBitcodeWriter::writeDIModule(const DIModule *N,
1917                                         SmallVectorImpl<uint64_t> &Record,
1918                                         unsigned Abbrev) {
1919   Record.push_back(N->isDistinct());
1920   for (auto &I : N->operands())
1921     Record.push_back(VE.getMetadataOrNullID(I));
1922   Record.push_back(N->getLineNo());
1923   Record.push_back(N->getIsDecl());
1924 
1925   Stream.EmitRecord(bitc::METADATA_MODULE, Record, Abbrev);
1926   Record.clear();
1927 }
1928 
1929 void ModuleBitcodeWriter::writeDITemplateTypeParameter(
1930     const DITemplateTypeParameter *N, SmallVectorImpl<uint64_t> &Record,
1931     unsigned Abbrev) {
1932   Record.push_back(N->isDistinct());
1933   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1934   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1935   Record.push_back(N->isDefault());
1936 
1937   Stream.EmitRecord(bitc::METADATA_TEMPLATE_TYPE, Record, Abbrev);
1938   Record.clear();
1939 }
1940 
1941 void ModuleBitcodeWriter::writeDITemplateValueParameter(
1942     const DITemplateValueParameter *N, SmallVectorImpl<uint64_t> &Record,
1943     unsigned Abbrev) {
1944   Record.push_back(N->isDistinct());
1945   Record.push_back(N->getTag());
1946   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1947   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1948   Record.push_back(N->isDefault());
1949   Record.push_back(VE.getMetadataOrNullID(N->getValue()));
1950 
1951   Stream.EmitRecord(bitc::METADATA_TEMPLATE_VALUE, Record, Abbrev);
1952   Record.clear();
1953 }
1954 
1955 void ModuleBitcodeWriter::writeDIGlobalVariable(
1956     const DIGlobalVariable *N, SmallVectorImpl<uint64_t> &Record,
1957     unsigned Abbrev) {
1958   const uint64_t Version = 2 << 1;
1959   Record.push_back((uint64_t)N->isDistinct() | Version);
1960   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1961   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1962   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1963   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1964   Record.push_back(N->getLine());
1965   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1966   Record.push_back(N->isLocalToUnit());
1967   Record.push_back(N->isDefinition());
1968   Record.push_back(VE.getMetadataOrNullID(N->getStaticDataMemberDeclaration()));
1969   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams()));
1970   Record.push_back(N->getAlignInBits());
1971   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1972 
1973   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR, Record, Abbrev);
1974   Record.clear();
1975 }
1976 
1977 void ModuleBitcodeWriter::writeDILocalVariable(
1978     const DILocalVariable *N, SmallVectorImpl<uint64_t> &Record,
1979     unsigned Abbrev) {
1980   // In order to support all possible bitcode formats in BitcodeReader we need
1981   // to distinguish the following cases:
1982   // 1) Record has no artificial tag (Record[1]),
1983   //   has no obsolete inlinedAt field (Record[9]).
1984   //   In this case Record size will be 8, HasAlignment flag is false.
1985   // 2) Record has artificial tag (Record[1]),
1986   //   has no obsolete inlignedAt field (Record[9]).
1987   //   In this case Record size will be 9, HasAlignment flag is false.
1988   // 3) Record has both artificial tag (Record[1]) and
1989   //   obsolete inlignedAt field (Record[9]).
1990   //   In this case Record size will be 10, HasAlignment flag is false.
1991   // 4) Record has neither artificial tag, nor inlignedAt field, but
1992   //   HasAlignment flag is true and Record[8] contains alignment value.
1993   const uint64_t HasAlignmentFlag = 1 << 1;
1994   Record.push_back((uint64_t)N->isDistinct() | HasAlignmentFlag);
1995   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1996   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1997   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1998   Record.push_back(N->getLine());
1999   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2000   Record.push_back(N->getArg());
2001   Record.push_back(N->getFlags());
2002   Record.push_back(N->getAlignInBits());
2003   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
2004 
2005   Stream.EmitRecord(bitc::METADATA_LOCAL_VAR, Record, Abbrev);
2006   Record.clear();
2007 }
2008 
2009 void ModuleBitcodeWriter::writeDILabel(
2010     const DILabel *N, SmallVectorImpl<uint64_t> &Record,
2011     unsigned Abbrev) {
2012   Record.push_back((uint64_t)N->isDistinct());
2013   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2014   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2015   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2016   Record.push_back(N->getLine());
2017 
2018   Stream.EmitRecord(bitc::METADATA_LABEL, Record, Abbrev);
2019   Record.clear();
2020 }
2021 
2022 void ModuleBitcodeWriter::writeDIExpression(const DIExpression *N,
2023                                             SmallVectorImpl<uint64_t> &Record,
2024                                             unsigned Abbrev) {
2025   Record.reserve(N->getElements().size() + 1);
2026   const uint64_t Version = 3 << 1;
2027   Record.push_back((uint64_t)N->isDistinct() | Version);
2028   Record.append(N->elements_begin(), N->elements_end());
2029 
2030   Stream.EmitRecord(bitc::METADATA_EXPRESSION, Record, Abbrev);
2031   Record.clear();
2032 }
2033 
2034 void ModuleBitcodeWriter::writeDIGlobalVariableExpression(
2035     const DIGlobalVariableExpression *N, SmallVectorImpl<uint64_t> &Record,
2036     unsigned Abbrev) {
2037   Record.push_back(N->isDistinct());
2038   Record.push_back(VE.getMetadataOrNullID(N->getVariable()));
2039   Record.push_back(VE.getMetadataOrNullID(N->getExpression()));
2040 
2041   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR_EXPR, Record, Abbrev);
2042   Record.clear();
2043 }
2044 
2045 void ModuleBitcodeWriter::writeDIObjCProperty(const DIObjCProperty *N,
2046                                               SmallVectorImpl<uint64_t> &Record,
2047                                               unsigned Abbrev) {
2048   Record.push_back(N->isDistinct());
2049   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2050   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2051   Record.push_back(N->getLine());
2052   Record.push_back(VE.getMetadataOrNullID(N->getRawSetterName()));
2053   Record.push_back(VE.getMetadataOrNullID(N->getRawGetterName()));
2054   Record.push_back(N->getAttributes());
2055   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2056 
2057   Stream.EmitRecord(bitc::METADATA_OBJC_PROPERTY, Record, Abbrev);
2058   Record.clear();
2059 }
2060 
2061 void ModuleBitcodeWriter::writeDIImportedEntity(
2062     const DIImportedEntity *N, SmallVectorImpl<uint64_t> &Record,
2063     unsigned Abbrev) {
2064   Record.push_back(N->isDistinct());
2065   Record.push_back(N->getTag());
2066   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2067   Record.push_back(VE.getMetadataOrNullID(N->getEntity()));
2068   Record.push_back(N->getLine());
2069   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2070   Record.push_back(VE.getMetadataOrNullID(N->getRawFile()));
2071   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
2072 
2073   Stream.EmitRecord(bitc::METADATA_IMPORTED_ENTITY, Record, Abbrev);
2074   Record.clear();
2075 }
2076 
2077 unsigned ModuleBitcodeWriter::createNamedMetadataAbbrev() {
2078   auto Abbv = std::make_shared<BitCodeAbbrev>();
2079   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
2080   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2081   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2082   return Stream.EmitAbbrev(std::move(Abbv));
2083 }
2084 
2085 void ModuleBitcodeWriter::writeNamedMetadata(
2086     SmallVectorImpl<uint64_t> &Record) {
2087   if (M.named_metadata_empty())
2088     return;
2089 
2090   unsigned Abbrev = createNamedMetadataAbbrev();
2091   for (const NamedMDNode &NMD : M.named_metadata()) {
2092     // Write name.
2093     StringRef Str = NMD.getName();
2094     Record.append(Str.bytes_begin(), Str.bytes_end());
2095     Stream.EmitRecord(bitc::METADATA_NAME, Record, Abbrev);
2096     Record.clear();
2097 
2098     // Write named metadata operands.
2099     for (const MDNode *N : NMD.operands())
2100       Record.push_back(VE.getMetadataID(N));
2101     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
2102     Record.clear();
2103   }
2104 }
2105 
2106 unsigned ModuleBitcodeWriter::createMetadataStringsAbbrev() {
2107   auto Abbv = std::make_shared<BitCodeAbbrev>();
2108   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRINGS));
2109   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // # of strings
2110   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // offset to chars
2111   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
2112   return Stream.EmitAbbrev(std::move(Abbv));
2113 }
2114 
2115 /// Write out a record for MDString.
2116 ///
2117 /// All the metadata strings in a metadata block are emitted in a single
2118 /// record.  The sizes and strings themselves are shoved into a blob.
2119 void ModuleBitcodeWriter::writeMetadataStrings(
2120     ArrayRef<const Metadata *> Strings, SmallVectorImpl<uint64_t> &Record) {
2121   if (Strings.empty())
2122     return;
2123 
2124   // Start the record with the number of strings.
2125   Record.push_back(bitc::METADATA_STRINGS);
2126   Record.push_back(Strings.size());
2127 
2128   // Emit the sizes of the strings in the blob.
2129   SmallString<256> Blob;
2130   {
2131     BitstreamWriter W(Blob);
2132     for (const Metadata *MD : Strings)
2133       W.EmitVBR(cast<MDString>(MD)->getLength(), 6);
2134     W.FlushToWord();
2135   }
2136 
2137   // Add the offset to the strings to the record.
2138   Record.push_back(Blob.size());
2139 
2140   // Add the strings to the blob.
2141   for (const Metadata *MD : Strings)
2142     Blob.append(cast<MDString>(MD)->getString());
2143 
2144   // Emit the final record.
2145   Stream.EmitRecordWithBlob(createMetadataStringsAbbrev(), Record, Blob);
2146   Record.clear();
2147 }
2148 
2149 // Generates an enum to use as an index in the Abbrev array of Metadata record.
2150 enum MetadataAbbrev : unsigned {
2151 #define HANDLE_MDNODE_LEAF(CLASS) CLASS##AbbrevID,
2152 #include "llvm/IR/Metadata.def"
2153   LastPlusOne
2154 };
2155 
2156 void ModuleBitcodeWriter::writeMetadataRecords(
2157     ArrayRef<const Metadata *> MDs, SmallVectorImpl<uint64_t> &Record,
2158     std::vector<unsigned> *MDAbbrevs, std::vector<uint64_t> *IndexPos) {
2159   if (MDs.empty())
2160     return;
2161 
2162   // Initialize MDNode abbreviations.
2163 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
2164 #include "llvm/IR/Metadata.def"
2165 
2166   for (const Metadata *MD : MDs) {
2167     if (IndexPos)
2168       IndexPos->push_back(Stream.GetCurrentBitNo());
2169     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
2170       assert(N->isResolved() && "Expected forward references to be resolved");
2171 
2172       switch (N->getMetadataID()) {
2173       default:
2174         llvm_unreachable("Invalid MDNode subclass");
2175 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
2176   case Metadata::CLASS##Kind:                                                  \
2177     if (MDAbbrevs)                                                             \
2178       write##CLASS(cast<CLASS>(N), Record,                                     \
2179                    (*MDAbbrevs)[MetadataAbbrev::CLASS##AbbrevID]);             \
2180     else                                                                       \
2181       write##CLASS(cast<CLASS>(N), Record, CLASS##Abbrev);                     \
2182     continue;
2183 #include "llvm/IR/Metadata.def"
2184       }
2185     }
2186     writeValueAsMetadata(cast<ValueAsMetadata>(MD), Record);
2187   }
2188 }
2189 
2190 void ModuleBitcodeWriter::writeModuleMetadata() {
2191   if (!VE.hasMDs() && M.named_metadata_empty())
2192     return;
2193 
2194   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 4);
2195   SmallVector<uint64_t, 64> Record;
2196 
2197   // Emit all abbrevs upfront, so that the reader can jump in the middle of the
2198   // block and load any metadata.
2199   std::vector<unsigned> MDAbbrevs;
2200 
2201   MDAbbrevs.resize(MetadataAbbrev::LastPlusOne);
2202   MDAbbrevs[MetadataAbbrev::DILocationAbbrevID] = createDILocationAbbrev();
2203   MDAbbrevs[MetadataAbbrev::GenericDINodeAbbrevID] =
2204       createGenericDINodeAbbrev();
2205 
2206   auto Abbv = std::make_shared<BitCodeAbbrev>();
2207   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX_OFFSET));
2208   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2209   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2210   unsigned OffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2211 
2212   Abbv = std::make_shared<BitCodeAbbrev>();
2213   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX));
2214   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2215   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2216   unsigned IndexAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2217 
2218   // Emit MDStrings together upfront.
2219   writeMetadataStrings(VE.getMDStrings(), Record);
2220 
2221   // We only emit an index for the metadata record if we have more than a given
2222   // (naive) threshold of metadatas, otherwise it is not worth it.
2223   if (VE.getNonMDStrings().size() > IndexThreshold) {
2224     // Write a placeholder value in for the offset of the metadata index,
2225     // which is written after the records, so that it can include
2226     // the offset of each entry. The placeholder offset will be
2227     // updated after all records are emitted.
2228     uint64_t Vals[] = {0, 0};
2229     Stream.EmitRecord(bitc::METADATA_INDEX_OFFSET, Vals, OffsetAbbrev);
2230   }
2231 
2232   // Compute and save the bit offset to the current position, which will be
2233   // patched when we emit the index later. We can simply subtract the 64-bit
2234   // fixed size from the current bit number to get the location to backpatch.
2235   uint64_t IndexOffsetRecordBitPos = Stream.GetCurrentBitNo();
2236 
2237   // This index will contain the bitpos for each individual record.
2238   std::vector<uint64_t> IndexPos;
2239   IndexPos.reserve(VE.getNonMDStrings().size());
2240 
2241   // Write all the records
2242   writeMetadataRecords(VE.getNonMDStrings(), Record, &MDAbbrevs, &IndexPos);
2243 
2244   if (VE.getNonMDStrings().size() > IndexThreshold) {
2245     // Now that we have emitted all the records we will emit the index. But
2246     // first
2247     // backpatch the forward reference so that the reader can skip the records
2248     // efficiently.
2249     Stream.BackpatchWord64(IndexOffsetRecordBitPos - 64,
2250                            Stream.GetCurrentBitNo() - IndexOffsetRecordBitPos);
2251 
2252     // Delta encode the index.
2253     uint64_t PreviousValue = IndexOffsetRecordBitPos;
2254     for (auto &Elt : IndexPos) {
2255       auto EltDelta = Elt - PreviousValue;
2256       PreviousValue = Elt;
2257       Elt = EltDelta;
2258     }
2259     // Emit the index record.
2260     Stream.EmitRecord(bitc::METADATA_INDEX, IndexPos, IndexAbbrev);
2261     IndexPos.clear();
2262   }
2263 
2264   // Write the named metadata now.
2265   writeNamedMetadata(Record);
2266 
2267   auto AddDeclAttachedMetadata = [&](const GlobalObject &GO) {
2268     SmallVector<uint64_t, 4> Record;
2269     Record.push_back(VE.getValueID(&GO));
2270     pushGlobalMetadataAttachment(Record, GO);
2271     Stream.EmitRecord(bitc::METADATA_GLOBAL_DECL_ATTACHMENT, Record);
2272   };
2273   for (const Function &F : M)
2274     if (F.isDeclaration() && F.hasMetadata())
2275       AddDeclAttachedMetadata(F);
2276   // FIXME: Only store metadata for declarations here, and move data for global
2277   // variable definitions to a separate block (PR28134).
2278   for (const GlobalVariable &GV : M.globals())
2279     if (GV.hasMetadata())
2280       AddDeclAttachedMetadata(GV);
2281 
2282   Stream.ExitBlock();
2283 }
2284 
2285 void ModuleBitcodeWriter::writeFunctionMetadata(const Function &F) {
2286   if (!VE.hasMDs())
2287     return;
2288 
2289   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
2290   SmallVector<uint64_t, 64> Record;
2291   writeMetadataStrings(VE.getMDStrings(), Record);
2292   writeMetadataRecords(VE.getNonMDStrings(), Record);
2293   Stream.ExitBlock();
2294 }
2295 
2296 void ModuleBitcodeWriter::pushGlobalMetadataAttachment(
2297     SmallVectorImpl<uint64_t> &Record, const GlobalObject &GO) {
2298   // [n x [id, mdnode]]
2299   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2300   GO.getAllMetadata(MDs);
2301   for (const auto &I : MDs) {
2302     Record.push_back(I.first);
2303     Record.push_back(VE.getMetadataID(I.second));
2304   }
2305 }
2306 
2307 void ModuleBitcodeWriter::writeFunctionMetadataAttachment(const Function &F) {
2308   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
2309 
2310   SmallVector<uint64_t, 64> Record;
2311 
2312   if (F.hasMetadata()) {
2313     pushGlobalMetadataAttachment(Record, F);
2314     Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2315     Record.clear();
2316   }
2317 
2318   // Write metadata attachments
2319   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
2320   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2321   for (const BasicBlock &BB : F)
2322     for (const Instruction &I : BB) {
2323       MDs.clear();
2324       I.getAllMetadataOtherThanDebugLoc(MDs);
2325 
2326       // If no metadata, ignore instruction.
2327       if (MDs.empty()) continue;
2328 
2329       Record.push_back(VE.getInstructionID(&I));
2330 
2331       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
2332         Record.push_back(MDs[i].first);
2333         Record.push_back(VE.getMetadataID(MDs[i].second));
2334       }
2335       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2336       Record.clear();
2337     }
2338 
2339   Stream.ExitBlock();
2340 }
2341 
2342 void ModuleBitcodeWriter::writeModuleMetadataKinds() {
2343   SmallVector<uint64_t, 64> Record;
2344 
2345   // Write metadata kinds
2346   // METADATA_KIND - [n x [id, name]]
2347   SmallVector<StringRef, 8> Names;
2348   M.getMDKindNames(Names);
2349 
2350   if (Names.empty()) return;
2351 
2352   Stream.EnterSubblock(bitc::METADATA_KIND_BLOCK_ID, 3);
2353 
2354   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
2355     Record.push_back(MDKindID);
2356     StringRef KName = Names[MDKindID];
2357     Record.append(KName.begin(), KName.end());
2358 
2359     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
2360     Record.clear();
2361   }
2362 
2363   Stream.ExitBlock();
2364 }
2365 
2366 void ModuleBitcodeWriter::writeOperandBundleTags() {
2367   // Write metadata kinds
2368   //
2369   // OPERAND_BUNDLE_TAGS_BLOCK_ID : N x OPERAND_BUNDLE_TAG
2370   //
2371   // OPERAND_BUNDLE_TAG - [strchr x N]
2372 
2373   SmallVector<StringRef, 8> Tags;
2374   M.getOperandBundleTags(Tags);
2375 
2376   if (Tags.empty())
2377     return;
2378 
2379   Stream.EnterSubblock(bitc::OPERAND_BUNDLE_TAGS_BLOCK_ID, 3);
2380 
2381   SmallVector<uint64_t, 64> Record;
2382 
2383   for (auto Tag : Tags) {
2384     Record.append(Tag.begin(), Tag.end());
2385 
2386     Stream.EmitRecord(bitc::OPERAND_BUNDLE_TAG, Record, 0);
2387     Record.clear();
2388   }
2389 
2390   Stream.ExitBlock();
2391 }
2392 
2393 void ModuleBitcodeWriter::writeSyncScopeNames() {
2394   SmallVector<StringRef, 8> SSNs;
2395   M.getContext().getSyncScopeNames(SSNs);
2396   if (SSNs.empty())
2397     return;
2398 
2399   Stream.EnterSubblock(bitc::SYNC_SCOPE_NAMES_BLOCK_ID, 2);
2400 
2401   SmallVector<uint64_t, 64> Record;
2402   for (auto SSN : SSNs) {
2403     Record.append(SSN.begin(), SSN.end());
2404     Stream.EmitRecord(bitc::SYNC_SCOPE_NAME, Record, 0);
2405     Record.clear();
2406   }
2407 
2408   Stream.ExitBlock();
2409 }
2410 
2411 void ModuleBitcodeWriter::writeConstants(unsigned FirstVal, unsigned LastVal,
2412                                          bool isGlobal) {
2413   if (FirstVal == LastVal) return;
2414 
2415   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
2416 
2417   unsigned AggregateAbbrev = 0;
2418   unsigned String8Abbrev = 0;
2419   unsigned CString7Abbrev = 0;
2420   unsigned CString6Abbrev = 0;
2421   // If this is a constant pool for the module, emit module-specific abbrevs.
2422   if (isGlobal) {
2423     // Abbrev for CST_CODE_AGGREGATE.
2424     auto Abbv = std::make_shared<BitCodeAbbrev>();
2425     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
2426     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2427     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
2428     AggregateAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2429 
2430     // Abbrev for CST_CODE_STRING.
2431     Abbv = std::make_shared<BitCodeAbbrev>();
2432     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
2433     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2434     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2435     String8Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2436     // Abbrev for CST_CODE_CSTRING.
2437     Abbv = std::make_shared<BitCodeAbbrev>();
2438     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2439     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2440     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2441     CString7Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2442     // Abbrev for CST_CODE_CSTRING.
2443     Abbv = std::make_shared<BitCodeAbbrev>();
2444     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2445     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2446     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2447     CString6Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2448   }
2449 
2450   SmallVector<uint64_t, 64> Record;
2451 
2452   const ValueEnumerator::ValueList &Vals = VE.getValues();
2453   Type *LastTy = nullptr;
2454   for (unsigned i = FirstVal; i != LastVal; ++i) {
2455     const Value *V = Vals[i].first;
2456     // If we need to switch types, do so now.
2457     if (V->getType() != LastTy) {
2458       LastTy = V->getType();
2459       Record.push_back(VE.getTypeID(LastTy));
2460       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
2461                         CONSTANTS_SETTYPE_ABBREV);
2462       Record.clear();
2463     }
2464 
2465     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
2466       Record.push_back(VE.getTypeID(IA->getFunctionType()));
2467       Record.push_back(
2468           unsigned(IA->hasSideEffects()) | unsigned(IA->isAlignStack()) << 1 |
2469           unsigned(IA->getDialect() & 1) << 2 | unsigned(IA->canThrow()) << 3);
2470 
2471       // Add the asm string.
2472       const std::string &AsmStr = IA->getAsmString();
2473       Record.push_back(AsmStr.size());
2474       Record.append(AsmStr.begin(), AsmStr.end());
2475 
2476       // Add the constraint string.
2477       const std::string &ConstraintStr = IA->getConstraintString();
2478       Record.push_back(ConstraintStr.size());
2479       Record.append(ConstraintStr.begin(), ConstraintStr.end());
2480       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
2481       Record.clear();
2482       continue;
2483     }
2484     const Constant *C = cast<Constant>(V);
2485     unsigned Code = -1U;
2486     unsigned AbbrevToUse = 0;
2487     if (C->isNullValue()) {
2488       Code = bitc::CST_CODE_NULL;
2489     } else if (isa<PoisonValue>(C)) {
2490       Code = bitc::CST_CODE_POISON;
2491     } else if (isa<UndefValue>(C)) {
2492       Code = bitc::CST_CODE_UNDEF;
2493     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
2494       if (IV->getBitWidth() <= 64) {
2495         uint64_t V = IV->getSExtValue();
2496         emitSignedInt64(Record, V);
2497         Code = bitc::CST_CODE_INTEGER;
2498         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
2499       } else {                             // Wide integers, > 64 bits in size.
2500         emitWideAPInt(Record, IV->getValue());
2501         Code = bitc::CST_CODE_WIDE_INTEGER;
2502       }
2503     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
2504       Code = bitc::CST_CODE_FLOAT;
2505       Type *Ty = CFP->getType();
2506       if (Ty->isHalfTy() || Ty->isBFloatTy() || Ty->isFloatTy() ||
2507           Ty->isDoubleTy()) {
2508         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
2509       } else if (Ty->isX86_FP80Ty()) {
2510         // api needed to prevent premature destruction
2511         // bits are not in the same order as a normal i80 APInt, compensate.
2512         APInt api = CFP->getValueAPF().bitcastToAPInt();
2513         const uint64_t *p = api.getRawData();
2514         Record.push_back((p[1] << 48) | (p[0] >> 16));
2515         Record.push_back(p[0] & 0xffffLL);
2516       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
2517         APInt api = CFP->getValueAPF().bitcastToAPInt();
2518         const uint64_t *p = api.getRawData();
2519         Record.push_back(p[0]);
2520         Record.push_back(p[1]);
2521       } else {
2522         assert(0 && "Unknown FP type!");
2523       }
2524     } else if (isa<ConstantDataSequential>(C) &&
2525                cast<ConstantDataSequential>(C)->isString()) {
2526       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
2527       // Emit constant strings specially.
2528       unsigned NumElts = Str->getNumElements();
2529       // If this is a null-terminated string, use the denser CSTRING encoding.
2530       if (Str->isCString()) {
2531         Code = bitc::CST_CODE_CSTRING;
2532         --NumElts;  // Don't encode the null, which isn't allowed by char6.
2533       } else {
2534         Code = bitc::CST_CODE_STRING;
2535         AbbrevToUse = String8Abbrev;
2536       }
2537       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
2538       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
2539       for (unsigned i = 0; i != NumElts; ++i) {
2540         unsigned char V = Str->getElementAsInteger(i);
2541         Record.push_back(V);
2542         isCStr7 &= (V & 128) == 0;
2543         if (isCStrChar6)
2544           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
2545       }
2546 
2547       if (isCStrChar6)
2548         AbbrevToUse = CString6Abbrev;
2549       else if (isCStr7)
2550         AbbrevToUse = CString7Abbrev;
2551     } else if (const ConstantDataSequential *CDS =
2552                   dyn_cast<ConstantDataSequential>(C)) {
2553       Code = bitc::CST_CODE_DATA;
2554       Type *EltTy = CDS->getElementType();
2555       if (isa<IntegerType>(EltTy)) {
2556         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2557           Record.push_back(CDS->getElementAsInteger(i));
2558       } else {
2559         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2560           Record.push_back(
2561               CDS->getElementAsAPFloat(i).bitcastToAPInt().getLimitedValue());
2562       }
2563     } else if (isa<ConstantAggregate>(C)) {
2564       Code = bitc::CST_CODE_AGGREGATE;
2565       for (const Value *Op : C->operands())
2566         Record.push_back(VE.getValueID(Op));
2567       AbbrevToUse = AggregateAbbrev;
2568     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
2569       switch (CE->getOpcode()) {
2570       default:
2571         if (Instruction::isCast(CE->getOpcode())) {
2572           Code = bitc::CST_CODE_CE_CAST;
2573           Record.push_back(getEncodedCastOpcode(CE->getOpcode()));
2574           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2575           Record.push_back(VE.getValueID(C->getOperand(0)));
2576           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
2577         } else {
2578           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
2579           Code = bitc::CST_CODE_CE_BINOP;
2580           Record.push_back(getEncodedBinaryOpcode(CE->getOpcode()));
2581           Record.push_back(VE.getValueID(C->getOperand(0)));
2582           Record.push_back(VE.getValueID(C->getOperand(1)));
2583           uint64_t Flags = getOptimizationFlags(CE);
2584           if (Flags != 0)
2585             Record.push_back(Flags);
2586         }
2587         break;
2588       case Instruction::FNeg: {
2589         assert(CE->getNumOperands() == 1 && "Unknown constant expr!");
2590         Code = bitc::CST_CODE_CE_UNOP;
2591         Record.push_back(getEncodedUnaryOpcode(CE->getOpcode()));
2592         Record.push_back(VE.getValueID(C->getOperand(0)));
2593         uint64_t Flags = getOptimizationFlags(CE);
2594         if (Flags != 0)
2595           Record.push_back(Flags);
2596         break;
2597       }
2598       case Instruction::GetElementPtr: {
2599         Code = bitc::CST_CODE_CE_GEP;
2600         const auto *GO = cast<GEPOperator>(C);
2601         Record.push_back(VE.getTypeID(GO->getSourceElementType()));
2602         if (Optional<unsigned> Idx = GO->getInRangeIndex()) {
2603           Code = bitc::CST_CODE_CE_GEP_WITH_INRANGE_INDEX;
2604           Record.push_back((*Idx << 1) | GO->isInBounds());
2605         } else if (GO->isInBounds())
2606           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
2607         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
2608           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
2609           Record.push_back(VE.getValueID(C->getOperand(i)));
2610         }
2611         break;
2612       }
2613       case Instruction::Select:
2614         Code = bitc::CST_CODE_CE_SELECT;
2615         Record.push_back(VE.getValueID(C->getOperand(0)));
2616         Record.push_back(VE.getValueID(C->getOperand(1)));
2617         Record.push_back(VE.getValueID(C->getOperand(2)));
2618         break;
2619       case Instruction::ExtractElement:
2620         Code = bitc::CST_CODE_CE_EXTRACTELT;
2621         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2622         Record.push_back(VE.getValueID(C->getOperand(0)));
2623         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
2624         Record.push_back(VE.getValueID(C->getOperand(1)));
2625         break;
2626       case Instruction::InsertElement:
2627         Code = bitc::CST_CODE_CE_INSERTELT;
2628         Record.push_back(VE.getValueID(C->getOperand(0)));
2629         Record.push_back(VE.getValueID(C->getOperand(1)));
2630         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
2631         Record.push_back(VE.getValueID(C->getOperand(2)));
2632         break;
2633       case Instruction::ShuffleVector:
2634         // If the return type and argument types are the same, this is a
2635         // standard shufflevector instruction.  If the types are different,
2636         // then the shuffle is widening or truncating the input vectors, and
2637         // the argument type must also be encoded.
2638         if (C->getType() == C->getOperand(0)->getType()) {
2639           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
2640         } else {
2641           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
2642           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2643         }
2644         Record.push_back(VE.getValueID(C->getOperand(0)));
2645         Record.push_back(VE.getValueID(C->getOperand(1)));
2646         Record.push_back(VE.getValueID(CE->getShuffleMaskForBitcode()));
2647         break;
2648       case Instruction::ICmp:
2649       case Instruction::FCmp:
2650         Code = bitc::CST_CODE_CE_CMP;
2651         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2652         Record.push_back(VE.getValueID(C->getOperand(0)));
2653         Record.push_back(VE.getValueID(C->getOperand(1)));
2654         Record.push_back(CE->getPredicate());
2655         break;
2656       }
2657     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
2658       Code = bitc::CST_CODE_BLOCKADDRESS;
2659       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
2660       Record.push_back(VE.getValueID(BA->getFunction()));
2661       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
2662     } else if (const auto *Equiv = dyn_cast<DSOLocalEquivalent>(C)) {
2663       Code = bitc::CST_CODE_DSO_LOCAL_EQUIVALENT;
2664       Record.push_back(VE.getTypeID(Equiv->getGlobalValue()->getType()));
2665       Record.push_back(VE.getValueID(Equiv->getGlobalValue()));
2666     } else if (const auto *NC = dyn_cast<NoCFIValue>(C)) {
2667       Code = bitc::CST_CODE_NO_CFI_VALUE;
2668       Record.push_back(VE.getTypeID(NC->getGlobalValue()->getType()));
2669       Record.push_back(VE.getValueID(NC->getGlobalValue()));
2670     } else {
2671 #ifndef NDEBUG
2672       C->dump();
2673 #endif
2674       llvm_unreachable("Unknown constant!");
2675     }
2676     Stream.EmitRecord(Code, Record, AbbrevToUse);
2677     Record.clear();
2678   }
2679 
2680   Stream.ExitBlock();
2681 }
2682 
2683 void ModuleBitcodeWriter::writeModuleConstants() {
2684   const ValueEnumerator::ValueList &Vals = VE.getValues();
2685 
2686   // Find the first constant to emit, which is the first non-globalvalue value.
2687   // We know globalvalues have been emitted by WriteModuleInfo.
2688   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
2689     if (!isa<GlobalValue>(Vals[i].first)) {
2690       writeConstants(i, Vals.size(), true);
2691       return;
2692     }
2693   }
2694 }
2695 
2696 /// pushValueAndType - The file has to encode both the value and type id for
2697 /// many values, because we need to know what type to create for forward
2698 /// references.  However, most operands are not forward references, so this type
2699 /// field is not needed.
2700 ///
2701 /// This function adds V's value ID to Vals.  If the value ID is higher than the
2702 /// instruction ID, then it is a forward reference, and it also includes the
2703 /// type ID.  The value ID that is written is encoded relative to the InstID.
2704 bool ModuleBitcodeWriter::pushValueAndType(const Value *V, unsigned InstID,
2705                                            SmallVectorImpl<unsigned> &Vals) {
2706   unsigned ValID = VE.getValueID(V);
2707   // Make encoding relative to the InstID.
2708   Vals.push_back(InstID - ValID);
2709   if (ValID >= InstID) {
2710     Vals.push_back(VE.getTypeID(V->getType()));
2711     return true;
2712   }
2713   return false;
2714 }
2715 
2716 void ModuleBitcodeWriter::writeOperandBundles(const CallBase &CS,
2717                                               unsigned InstID) {
2718   SmallVector<unsigned, 64> Record;
2719   LLVMContext &C = CS.getContext();
2720 
2721   for (unsigned i = 0, e = CS.getNumOperandBundles(); i != e; ++i) {
2722     const auto &Bundle = CS.getOperandBundleAt(i);
2723     Record.push_back(C.getOperandBundleTagID(Bundle.getTagName()));
2724 
2725     for (auto &Input : Bundle.Inputs)
2726       pushValueAndType(Input, InstID, Record);
2727 
2728     Stream.EmitRecord(bitc::FUNC_CODE_OPERAND_BUNDLE, Record);
2729     Record.clear();
2730   }
2731 }
2732 
2733 /// pushValue - Like pushValueAndType, but where the type of the value is
2734 /// omitted (perhaps it was already encoded in an earlier operand).
2735 void ModuleBitcodeWriter::pushValue(const Value *V, unsigned InstID,
2736                                     SmallVectorImpl<unsigned> &Vals) {
2737   unsigned ValID = VE.getValueID(V);
2738   Vals.push_back(InstID - ValID);
2739 }
2740 
2741 void ModuleBitcodeWriter::pushValueSigned(const Value *V, unsigned InstID,
2742                                           SmallVectorImpl<uint64_t> &Vals) {
2743   unsigned ValID = VE.getValueID(V);
2744   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
2745   emitSignedInt64(Vals, diff);
2746 }
2747 
2748 /// WriteInstruction - Emit an instruction to the specified stream.
2749 void ModuleBitcodeWriter::writeInstruction(const Instruction &I,
2750                                            unsigned InstID,
2751                                            SmallVectorImpl<unsigned> &Vals) {
2752   unsigned Code = 0;
2753   unsigned AbbrevToUse = 0;
2754   VE.setInstructionID(&I);
2755   switch (I.getOpcode()) {
2756   default:
2757     if (Instruction::isCast(I.getOpcode())) {
2758       Code = bitc::FUNC_CODE_INST_CAST;
2759       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2760         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
2761       Vals.push_back(VE.getTypeID(I.getType()));
2762       Vals.push_back(getEncodedCastOpcode(I.getOpcode()));
2763     } else {
2764       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
2765       Code = bitc::FUNC_CODE_INST_BINOP;
2766       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2767         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
2768       pushValue(I.getOperand(1), InstID, Vals);
2769       Vals.push_back(getEncodedBinaryOpcode(I.getOpcode()));
2770       uint64_t Flags = getOptimizationFlags(&I);
2771       if (Flags != 0) {
2772         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
2773           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
2774         Vals.push_back(Flags);
2775       }
2776     }
2777     break;
2778   case Instruction::FNeg: {
2779     Code = bitc::FUNC_CODE_INST_UNOP;
2780     if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2781       AbbrevToUse = FUNCTION_INST_UNOP_ABBREV;
2782     Vals.push_back(getEncodedUnaryOpcode(I.getOpcode()));
2783     uint64_t Flags = getOptimizationFlags(&I);
2784     if (Flags != 0) {
2785       if (AbbrevToUse == FUNCTION_INST_UNOP_ABBREV)
2786         AbbrevToUse = FUNCTION_INST_UNOP_FLAGS_ABBREV;
2787       Vals.push_back(Flags);
2788     }
2789     break;
2790   }
2791   case Instruction::GetElementPtr: {
2792     Code = bitc::FUNC_CODE_INST_GEP;
2793     AbbrevToUse = FUNCTION_INST_GEP_ABBREV;
2794     auto &GEPInst = cast<GetElementPtrInst>(I);
2795     Vals.push_back(GEPInst.isInBounds());
2796     Vals.push_back(VE.getTypeID(GEPInst.getSourceElementType()));
2797     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
2798       pushValueAndType(I.getOperand(i), InstID, Vals);
2799     break;
2800   }
2801   case Instruction::ExtractValue: {
2802     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
2803     pushValueAndType(I.getOperand(0), InstID, Vals);
2804     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
2805     Vals.append(EVI->idx_begin(), EVI->idx_end());
2806     break;
2807   }
2808   case Instruction::InsertValue: {
2809     Code = bitc::FUNC_CODE_INST_INSERTVAL;
2810     pushValueAndType(I.getOperand(0), InstID, Vals);
2811     pushValueAndType(I.getOperand(1), InstID, Vals);
2812     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
2813     Vals.append(IVI->idx_begin(), IVI->idx_end());
2814     break;
2815   }
2816   case Instruction::Select: {
2817     Code = bitc::FUNC_CODE_INST_VSELECT;
2818     pushValueAndType(I.getOperand(1), InstID, Vals);
2819     pushValue(I.getOperand(2), InstID, Vals);
2820     pushValueAndType(I.getOperand(0), InstID, Vals);
2821     uint64_t Flags = getOptimizationFlags(&I);
2822     if (Flags != 0)
2823       Vals.push_back(Flags);
2824     break;
2825   }
2826   case Instruction::ExtractElement:
2827     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
2828     pushValueAndType(I.getOperand(0), InstID, Vals);
2829     pushValueAndType(I.getOperand(1), InstID, Vals);
2830     break;
2831   case Instruction::InsertElement:
2832     Code = bitc::FUNC_CODE_INST_INSERTELT;
2833     pushValueAndType(I.getOperand(0), InstID, Vals);
2834     pushValue(I.getOperand(1), InstID, Vals);
2835     pushValueAndType(I.getOperand(2), InstID, Vals);
2836     break;
2837   case Instruction::ShuffleVector:
2838     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
2839     pushValueAndType(I.getOperand(0), InstID, Vals);
2840     pushValue(I.getOperand(1), InstID, Vals);
2841     pushValue(cast<ShuffleVectorInst>(I).getShuffleMaskForBitcode(), InstID,
2842               Vals);
2843     break;
2844   case Instruction::ICmp:
2845   case Instruction::FCmp: {
2846     // compare returning Int1Ty or vector of Int1Ty
2847     Code = bitc::FUNC_CODE_INST_CMP2;
2848     pushValueAndType(I.getOperand(0), InstID, Vals);
2849     pushValue(I.getOperand(1), InstID, Vals);
2850     Vals.push_back(cast<CmpInst>(I).getPredicate());
2851     uint64_t Flags = getOptimizationFlags(&I);
2852     if (Flags != 0)
2853       Vals.push_back(Flags);
2854     break;
2855   }
2856 
2857   case Instruction::Ret:
2858     {
2859       Code = bitc::FUNC_CODE_INST_RET;
2860       unsigned NumOperands = I.getNumOperands();
2861       if (NumOperands == 0)
2862         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
2863       else if (NumOperands == 1) {
2864         if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2865           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
2866       } else {
2867         for (unsigned i = 0, e = NumOperands; i != e; ++i)
2868           pushValueAndType(I.getOperand(i), InstID, Vals);
2869       }
2870     }
2871     break;
2872   case Instruction::Br:
2873     {
2874       Code = bitc::FUNC_CODE_INST_BR;
2875       const BranchInst &II = cast<BranchInst>(I);
2876       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
2877       if (II.isConditional()) {
2878         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
2879         pushValue(II.getCondition(), InstID, Vals);
2880       }
2881     }
2882     break;
2883   case Instruction::Switch:
2884     {
2885       Code = bitc::FUNC_CODE_INST_SWITCH;
2886       const SwitchInst &SI = cast<SwitchInst>(I);
2887       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
2888       pushValue(SI.getCondition(), InstID, Vals);
2889       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
2890       for (auto Case : SI.cases()) {
2891         Vals.push_back(VE.getValueID(Case.getCaseValue()));
2892         Vals.push_back(VE.getValueID(Case.getCaseSuccessor()));
2893       }
2894     }
2895     break;
2896   case Instruction::IndirectBr:
2897     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
2898     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2899     // Encode the address operand as relative, but not the basic blocks.
2900     pushValue(I.getOperand(0), InstID, Vals);
2901     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
2902       Vals.push_back(VE.getValueID(I.getOperand(i)));
2903     break;
2904 
2905   case Instruction::Invoke: {
2906     const InvokeInst *II = cast<InvokeInst>(&I);
2907     const Value *Callee = II->getCalledOperand();
2908     FunctionType *FTy = II->getFunctionType();
2909 
2910     if (II->hasOperandBundles())
2911       writeOperandBundles(*II, InstID);
2912 
2913     Code = bitc::FUNC_CODE_INST_INVOKE;
2914 
2915     Vals.push_back(VE.getAttributeListID(II->getAttributes()));
2916     Vals.push_back(II->getCallingConv() | 1 << 13);
2917     Vals.push_back(VE.getValueID(II->getNormalDest()));
2918     Vals.push_back(VE.getValueID(II->getUnwindDest()));
2919     Vals.push_back(VE.getTypeID(FTy));
2920     pushValueAndType(Callee, InstID, Vals);
2921 
2922     // Emit value #'s for the fixed parameters.
2923     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
2924       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
2925 
2926     // Emit type/value pairs for varargs params.
2927     if (FTy->isVarArg()) {
2928       for (unsigned i = FTy->getNumParams(), e = II->arg_size(); i != e; ++i)
2929         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
2930     }
2931     break;
2932   }
2933   case Instruction::Resume:
2934     Code = bitc::FUNC_CODE_INST_RESUME;
2935     pushValueAndType(I.getOperand(0), InstID, Vals);
2936     break;
2937   case Instruction::CleanupRet: {
2938     Code = bitc::FUNC_CODE_INST_CLEANUPRET;
2939     const auto &CRI = cast<CleanupReturnInst>(I);
2940     pushValue(CRI.getCleanupPad(), InstID, Vals);
2941     if (CRI.hasUnwindDest())
2942       Vals.push_back(VE.getValueID(CRI.getUnwindDest()));
2943     break;
2944   }
2945   case Instruction::CatchRet: {
2946     Code = bitc::FUNC_CODE_INST_CATCHRET;
2947     const auto &CRI = cast<CatchReturnInst>(I);
2948     pushValue(CRI.getCatchPad(), InstID, Vals);
2949     Vals.push_back(VE.getValueID(CRI.getSuccessor()));
2950     break;
2951   }
2952   case Instruction::CleanupPad:
2953   case Instruction::CatchPad: {
2954     const auto &FuncletPad = cast<FuncletPadInst>(I);
2955     Code = isa<CatchPadInst>(FuncletPad) ? bitc::FUNC_CODE_INST_CATCHPAD
2956                                          : bitc::FUNC_CODE_INST_CLEANUPPAD;
2957     pushValue(FuncletPad.getParentPad(), InstID, Vals);
2958 
2959     unsigned NumArgOperands = FuncletPad.getNumArgOperands();
2960     Vals.push_back(NumArgOperands);
2961     for (unsigned Op = 0; Op != NumArgOperands; ++Op)
2962       pushValueAndType(FuncletPad.getArgOperand(Op), InstID, Vals);
2963     break;
2964   }
2965   case Instruction::CatchSwitch: {
2966     Code = bitc::FUNC_CODE_INST_CATCHSWITCH;
2967     const auto &CatchSwitch = cast<CatchSwitchInst>(I);
2968 
2969     pushValue(CatchSwitch.getParentPad(), InstID, Vals);
2970 
2971     unsigned NumHandlers = CatchSwitch.getNumHandlers();
2972     Vals.push_back(NumHandlers);
2973     for (const BasicBlock *CatchPadBB : CatchSwitch.handlers())
2974       Vals.push_back(VE.getValueID(CatchPadBB));
2975 
2976     if (CatchSwitch.hasUnwindDest())
2977       Vals.push_back(VE.getValueID(CatchSwitch.getUnwindDest()));
2978     break;
2979   }
2980   case Instruction::CallBr: {
2981     const CallBrInst *CBI = cast<CallBrInst>(&I);
2982     const Value *Callee = CBI->getCalledOperand();
2983     FunctionType *FTy = CBI->getFunctionType();
2984 
2985     if (CBI->hasOperandBundles())
2986       writeOperandBundles(*CBI, InstID);
2987 
2988     Code = bitc::FUNC_CODE_INST_CALLBR;
2989 
2990     Vals.push_back(VE.getAttributeListID(CBI->getAttributes()));
2991 
2992     Vals.push_back(CBI->getCallingConv() << bitc::CALL_CCONV |
2993                    1 << bitc::CALL_EXPLICIT_TYPE);
2994 
2995     Vals.push_back(VE.getValueID(CBI->getDefaultDest()));
2996     Vals.push_back(CBI->getNumIndirectDests());
2997     for (unsigned i = 0, e = CBI->getNumIndirectDests(); i != e; ++i)
2998       Vals.push_back(VE.getValueID(CBI->getIndirectDest(i)));
2999 
3000     Vals.push_back(VE.getTypeID(FTy));
3001     pushValueAndType(Callee, InstID, Vals);
3002 
3003     // Emit value #'s for the fixed parameters.
3004     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
3005       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
3006 
3007     // Emit type/value pairs for varargs params.
3008     if (FTy->isVarArg()) {
3009       for (unsigned i = FTy->getNumParams(), e = CBI->arg_size(); i != e; ++i)
3010         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
3011     }
3012     break;
3013   }
3014   case Instruction::Unreachable:
3015     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
3016     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
3017     break;
3018 
3019   case Instruction::PHI: {
3020     const PHINode &PN = cast<PHINode>(I);
3021     Code = bitc::FUNC_CODE_INST_PHI;
3022     // With the newer instruction encoding, forward references could give
3023     // negative valued IDs.  This is most common for PHIs, so we use
3024     // signed VBRs.
3025     SmallVector<uint64_t, 128> Vals64;
3026     Vals64.push_back(VE.getTypeID(PN.getType()));
3027     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
3028       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64);
3029       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
3030     }
3031 
3032     uint64_t Flags = getOptimizationFlags(&I);
3033     if (Flags != 0)
3034       Vals64.push_back(Flags);
3035 
3036     // Emit a Vals64 vector and exit.
3037     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
3038     Vals64.clear();
3039     return;
3040   }
3041 
3042   case Instruction::LandingPad: {
3043     const LandingPadInst &LP = cast<LandingPadInst>(I);
3044     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
3045     Vals.push_back(VE.getTypeID(LP.getType()));
3046     Vals.push_back(LP.isCleanup());
3047     Vals.push_back(LP.getNumClauses());
3048     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
3049       if (LP.isCatch(I))
3050         Vals.push_back(LandingPadInst::Catch);
3051       else
3052         Vals.push_back(LandingPadInst::Filter);
3053       pushValueAndType(LP.getClause(I), InstID, Vals);
3054     }
3055     break;
3056   }
3057 
3058   case Instruction::Alloca: {
3059     Code = bitc::FUNC_CODE_INST_ALLOCA;
3060     const AllocaInst &AI = cast<AllocaInst>(I);
3061     Vals.push_back(VE.getTypeID(AI.getAllocatedType()));
3062     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
3063     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
3064     using APV = AllocaPackedValues;
3065     unsigned Record = 0;
3066     unsigned EncodedAlign = getEncodedAlign(AI.getAlign());
3067     Bitfield::set<APV::AlignLower>(
3068         Record, EncodedAlign & ((1 << APV::AlignLower::Bits) - 1));
3069     Bitfield::set<APV::AlignUpper>(Record,
3070                                    EncodedAlign >> APV::AlignLower::Bits);
3071     Bitfield::set<APV::UsedWithInAlloca>(Record, AI.isUsedWithInAlloca());
3072     Bitfield::set<APV::ExplicitType>(Record, true);
3073     Bitfield::set<APV::SwiftError>(Record, AI.isSwiftError());
3074     Vals.push_back(Record);
3075     break;
3076   }
3077 
3078   case Instruction::Load:
3079     if (cast<LoadInst>(I).isAtomic()) {
3080       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
3081       pushValueAndType(I.getOperand(0), InstID, Vals);
3082     } else {
3083       Code = bitc::FUNC_CODE_INST_LOAD;
3084       if (!pushValueAndType(I.getOperand(0), InstID, Vals)) // ptr
3085         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
3086     }
3087     Vals.push_back(VE.getTypeID(I.getType()));
3088     Vals.push_back(getEncodedAlign(cast<LoadInst>(I).getAlign()));
3089     Vals.push_back(cast<LoadInst>(I).isVolatile());
3090     if (cast<LoadInst>(I).isAtomic()) {
3091       Vals.push_back(getEncodedOrdering(cast<LoadInst>(I).getOrdering()));
3092       Vals.push_back(getEncodedSyncScopeID(cast<LoadInst>(I).getSyncScopeID()));
3093     }
3094     break;
3095   case Instruction::Store:
3096     if (cast<StoreInst>(I).isAtomic())
3097       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
3098     else
3099       Code = bitc::FUNC_CODE_INST_STORE;
3100     pushValueAndType(I.getOperand(1), InstID, Vals); // ptrty + ptr
3101     pushValueAndType(I.getOperand(0), InstID, Vals); // valty + val
3102     Vals.push_back(getEncodedAlign(cast<StoreInst>(I).getAlign()));
3103     Vals.push_back(cast<StoreInst>(I).isVolatile());
3104     if (cast<StoreInst>(I).isAtomic()) {
3105       Vals.push_back(getEncodedOrdering(cast<StoreInst>(I).getOrdering()));
3106       Vals.push_back(
3107           getEncodedSyncScopeID(cast<StoreInst>(I).getSyncScopeID()));
3108     }
3109     break;
3110   case Instruction::AtomicCmpXchg:
3111     Code = bitc::FUNC_CODE_INST_CMPXCHG;
3112     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
3113     pushValueAndType(I.getOperand(1), InstID, Vals); // cmp.
3114     pushValue(I.getOperand(2), InstID, Vals);        // newval.
3115     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
3116     Vals.push_back(
3117         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
3118     Vals.push_back(
3119         getEncodedSyncScopeID(cast<AtomicCmpXchgInst>(I).getSyncScopeID()));
3120     Vals.push_back(
3121         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
3122     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
3123     Vals.push_back(getEncodedAlign(cast<AtomicCmpXchgInst>(I).getAlign()));
3124     break;
3125   case Instruction::AtomicRMW:
3126     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
3127     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
3128     pushValueAndType(I.getOperand(1), InstID, Vals); // valty + val
3129     Vals.push_back(
3130         getEncodedRMWOperation(cast<AtomicRMWInst>(I).getOperation()));
3131     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
3132     Vals.push_back(getEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
3133     Vals.push_back(
3134         getEncodedSyncScopeID(cast<AtomicRMWInst>(I).getSyncScopeID()));
3135     Vals.push_back(getEncodedAlign(cast<AtomicRMWInst>(I).getAlign()));
3136     break;
3137   case Instruction::Fence:
3138     Code = bitc::FUNC_CODE_INST_FENCE;
3139     Vals.push_back(getEncodedOrdering(cast<FenceInst>(I).getOrdering()));
3140     Vals.push_back(getEncodedSyncScopeID(cast<FenceInst>(I).getSyncScopeID()));
3141     break;
3142   case Instruction::Call: {
3143     const CallInst &CI = cast<CallInst>(I);
3144     FunctionType *FTy = CI.getFunctionType();
3145 
3146     if (CI.hasOperandBundles())
3147       writeOperandBundles(CI, InstID);
3148 
3149     Code = bitc::FUNC_CODE_INST_CALL;
3150 
3151     Vals.push_back(VE.getAttributeListID(CI.getAttributes()));
3152 
3153     unsigned Flags = getOptimizationFlags(&I);
3154     Vals.push_back(CI.getCallingConv() << bitc::CALL_CCONV |
3155                    unsigned(CI.isTailCall()) << bitc::CALL_TAIL |
3156                    unsigned(CI.isMustTailCall()) << bitc::CALL_MUSTTAIL |
3157                    1 << bitc::CALL_EXPLICIT_TYPE |
3158                    unsigned(CI.isNoTailCall()) << bitc::CALL_NOTAIL |
3159                    unsigned(Flags != 0) << bitc::CALL_FMF);
3160     if (Flags != 0)
3161       Vals.push_back(Flags);
3162 
3163     Vals.push_back(VE.getTypeID(FTy));
3164     pushValueAndType(CI.getCalledOperand(), InstID, Vals); // Callee
3165 
3166     // Emit value #'s for the fixed parameters.
3167     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
3168       // Check for labels (can happen with asm labels).
3169       if (FTy->getParamType(i)->isLabelTy())
3170         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
3171       else
3172         pushValue(CI.getArgOperand(i), InstID, Vals); // fixed param.
3173     }
3174 
3175     // Emit type/value pairs for varargs params.
3176     if (FTy->isVarArg()) {
3177       for (unsigned i = FTy->getNumParams(), e = CI.arg_size(); i != e; ++i)
3178         pushValueAndType(CI.getArgOperand(i), InstID, Vals); // varargs
3179     }
3180     break;
3181   }
3182   case Instruction::VAArg:
3183     Code = bitc::FUNC_CODE_INST_VAARG;
3184     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
3185     pushValue(I.getOperand(0), InstID, Vals);                   // valist.
3186     Vals.push_back(VE.getTypeID(I.getType())); // restype.
3187     break;
3188   case Instruction::Freeze:
3189     Code = bitc::FUNC_CODE_INST_FREEZE;
3190     pushValueAndType(I.getOperand(0), InstID, Vals);
3191     break;
3192   }
3193 
3194   Stream.EmitRecord(Code, Vals, AbbrevToUse);
3195   Vals.clear();
3196 }
3197 
3198 /// Write a GlobalValue VST to the module. The purpose of this data structure is
3199 /// to allow clients to efficiently find the function body.
3200 void ModuleBitcodeWriter::writeGlobalValueSymbolTable(
3201   DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3202   // Get the offset of the VST we are writing, and backpatch it into
3203   // the VST forward declaration record.
3204   uint64_t VSTOffset = Stream.GetCurrentBitNo();
3205   // The BitcodeStartBit was the stream offset of the identification block.
3206   VSTOffset -= bitcodeStartBit();
3207   assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
3208   // Note that we add 1 here because the offset is relative to one word
3209   // before the start of the identification block, which was historically
3210   // always the start of the regular bitcode header.
3211   Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32 + 1);
3212 
3213   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3214 
3215   auto Abbv = std::make_shared<BitCodeAbbrev>();
3216   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
3217   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
3218   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
3219   unsigned FnEntryAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3220 
3221   for (const Function &F : M) {
3222     uint64_t Record[2];
3223 
3224     if (F.isDeclaration())
3225       continue;
3226 
3227     Record[0] = VE.getValueID(&F);
3228 
3229     // Save the word offset of the function (from the start of the
3230     // actual bitcode written to the stream).
3231     uint64_t BitcodeIndex = FunctionToBitcodeIndex[&F] - bitcodeStartBit();
3232     assert((BitcodeIndex & 31) == 0 && "function block not 32-bit aligned");
3233     // Note that we add 1 here because the offset is relative to one word
3234     // before the start of the identification block, which was historically
3235     // always the start of the regular bitcode header.
3236     Record[1] = BitcodeIndex / 32 + 1;
3237 
3238     Stream.EmitRecord(bitc::VST_CODE_FNENTRY, Record, FnEntryAbbrev);
3239   }
3240 
3241   Stream.ExitBlock();
3242 }
3243 
3244 /// Emit names for arguments, instructions and basic blocks in a function.
3245 void ModuleBitcodeWriter::writeFunctionLevelValueSymbolTable(
3246     const ValueSymbolTable &VST) {
3247   if (VST.empty())
3248     return;
3249 
3250   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3251 
3252   // FIXME: Set up the abbrev, we know how many values there are!
3253   // FIXME: We know if the type names can use 7-bit ascii.
3254   SmallVector<uint64_t, 64> NameVals;
3255 
3256   for (const ValueName &Name : VST) {
3257     // Figure out the encoding to use for the name.
3258     StringEncoding Bits = getStringEncoding(Name.getKey());
3259 
3260     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
3261     NameVals.push_back(VE.getValueID(Name.getValue()));
3262 
3263     // VST_CODE_ENTRY:   [valueid, namechar x N]
3264     // VST_CODE_BBENTRY: [bbid, namechar x N]
3265     unsigned Code;
3266     if (isa<BasicBlock>(Name.getValue())) {
3267       Code = bitc::VST_CODE_BBENTRY;
3268       if (Bits == SE_Char6)
3269         AbbrevToUse = VST_BBENTRY_6_ABBREV;
3270     } else {
3271       Code = bitc::VST_CODE_ENTRY;
3272       if (Bits == SE_Char6)
3273         AbbrevToUse = VST_ENTRY_6_ABBREV;
3274       else if (Bits == SE_Fixed7)
3275         AbbrevToUse = VST_ENTRY_7_ABBREV;
3276     }
3277 
3278     for (const auto P : Name.getKey())
3279       NameVals.push_back((unsigned char)P);
3280 
3281     // Emit the finished record.
3282     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
3283     NameVals.clear();
3284   }
3285 
3286   Stream.ExitBlock();
3287 }
3288 
3289 void ModuleBitcodeWriter::writeUseList(UseListOrder &&Order) {
3290   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
3291   unsigned Code;
3292   if (isa<BasicBlock>(Order.V))
3293     Code = bitc::USELIST_CODE_BB;
3294   else
3295     Code = bitc::USELIST_CODE_DEFAULT;
3296 
3297   SmallVector<uint64_t, 64> Record(Order.Shuffle.begin(), Order.Shuffle.end());
3298   Record.push_back(VE.getValueID(Order.V));
3299   Stream.EmitRecord(Code, Record);
3300 }
3301 
3302 void ModuleBitcodeWriter::writeUseListBlock(const Function *F) {
3303   assert(VE.shouldPreserveUseListOrder() &&
3304          "Expected to be preserving use-list order");
3305 
3306   auto hasMore = [&]() {
3307     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
3308   };
3309   if (!hasMore())
3310     // Nothing to do.
3311     return;
3312 
3313   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
3314   while (hasMore()) {
3315     writeUseList(std::move(VE.UseListOrders.back()));
3316     VE.UseListOrders.pop_back();
3317   }
3318   Stream.ExitBlock();
3319 }
3320 
3321 /// Emit a function body to the module stream.
3322 void ModuleBitcodeWriter::writeFunction(
3323     const Function &F,
3324     DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3325   // Save the bitcode index of the start of this function block for recording
3326   // in the VST.
3327   FunctionToBitcodeIndex[&F] = Stream.GetCurrentBitNo();
3328 
3329   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
3330   VE.incorporateFunction(F);
3331 
3332   SmallVector<unsigned, 64> Vals;
3333 
3334   // Emit the number of basic blocks, so the reader can create them ahead of
3335   // time.
3336   Vals.push_back(VE.getBasicBlocks().size());
3337   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
3338   Vals.clear();
3339 
3340   // If there are function-local constants, emit them now.
3341   unsigned CstStart, CstEnd;
3342   VE.getFunctionConstantRange(CstStart, CstEnd);
3343   writeConstants(CstStart, CstEnd, false);
3344 
3345   // If there is function-local metadata, emit it now.
3346   writeFunctionMetadata(F);
3347 
3348   // Keep a running idea of what the instruction ID is.
3349   unsigned InstID = CstEnd;
3350 
3351   bool NeedsMetadataAttachment = F.hasMetadata();
3352 
3353   DILocation *LastDL = nullptr;
3354   // Finally, emit all the instructions, in order.
3355   for (const BasicBlock &BB : F)
3356     for (const Instruction &I : BB) {
3357       writeInstruction(I, InstID, Vals);
3358 
3359       if (!I.getType()->isVoidTy())
3360         ++InstID;
3361 
3362       // If the instruction has metadata, write a metadata attachment later.
3363       NeedsMetadataAttachment |= I.hasMetadataOtherThanDebugLoc();
3364 
3365       // If the instruction has a debug location, emit it.
3366       DILocation *DL = I.getDebugLoc();
3367       if (!DL)
3368         continue;
3369 
3370       if (DL == LastDL) {
3371         // Just repeat the same debug loc as last time.
3372         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
3373         continue;
3374       }
3375 
3376       Vals.push_back(DL->getLine());
3377       Vals.push_back(DL->getColumn());
3378       Vals.push_back(VE.getMetadataOrNullID(DL->getScope()));
3379       Vals.push_back(VE.getMetadataOrNullID(DL->getInlinedAt()));
3380       Vals.push_back(DL->isImplicitCode());
3381       Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
3382       Vals.clear();
3383 
3384       LastDL = DL;
3385     }
3386 
3387   // Emit names for all the instructions etc.
3388   if (auto *Symtab = F.getValueSymbolTable())
3389     writeFunctionLevelValueSymbolTable(*Symtab);
3390 
3391   if (NeedsMetadataAttachment)
3392     writeFunctionMetadataAttachment(F);
3393   if (VE.shouldPreserveUseListOrder())
3394     writeUseListBlock(&F);
3395   VE.purgeFunction();
3396   Stream.ExitBlock();
3397 }
3398 
3399 // Emit blockinfo, which defines the standard abbreviations etc.
3400 void ModuleBitcodeWriter::writeBlockInfo() {
3401   // We only want to emit block info records for blocks that have multiple
3402   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
3403   // Other blocks can define their abbrevs inline.
3404   Stream.EnterBlockInfoBlock();
3405 
3406   { // 8-bit fixed-width VST_CODE_ENTRY/VST_CODE_BBENTRY strings.
3407     auto Abbv = std::make_shared<BitCodeAbbrev>();
3408     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
3409     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3410     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3411     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3412     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3413         VST_ENTRY_8_ABBREV)
3414       llvm_unreachable("Unexpected abbrev ordering!");
3415   }
3416 
3417   { // 7-bit fixed width VST_CODE_ENTRY strings.
3418     auto Abbv = std::make_shared<BitCodeAbbrev>();
3419     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3420     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3421     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3422     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3423     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3424         VST_ENTRY_7_ABBREV)
3425       llvm_unreachable("Unexpected abbrev ordering!");
3426   }
3427   { // 6-bit char6 VST_CODE_ENTRY strings.
3428     auto Abbv = std::make_shared<BitCodeAbbrev>();
3429     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3430     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3431     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3432     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3433     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3434         VST_ENTRY_6_ABBREV)
3435       llvm_unreachable("Unexpected abbrev ordering!");
3436   }
3437   { // 6-bit char6 VST_CODE_BBENTRY strings.
3438     auto Abbv = std::make_shared<BitCodeAbbrev>();
3439     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
3440     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3441     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3442     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3443     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3444         VST_BBENTRY_6_ABBREV)
3445       llvm_unreachable("Unexpected abbrev ordering!");
3446   }
3447 
3448   { // SETTYPE abbrev for CONSTANTS_BLOCK.
3449     auto Abbv = std::make_shared<BitCodeAbbrev>();
3450     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
3451     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
3452                               VE.computeBitsRequiredForTypeIndicies()));
3453     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3454         CONSTANTS_SETTYPE_ABBREV)
3455       llvm_unreachable("Unexpected abbrev ordering!");
3456   }
3457 
3458   { // INTEGER abbrev for CONSTANTS_BLOCK.
3459     auto Abbv = std::make_shared<BitCodeAbbrev>();
3460     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
3461     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3462     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3463         CONSTANTS_INTEGER_ABBREV)
3464       llvm_unreachable("Unexpected abbrev ordering!");
3465   }
3466 
3467   { // CE_CAST abbrev for CONSTANTS_BLOCK.
3468     auto Abbv = std::make_shared<BitCodeAbbrev>();
3469     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
3470     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
3471     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
3472                               VE.computeBitsRequiredForTypeIndicies()));
3473     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
3474 
3475     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3476         CONSTANTS_CE_CAST_Abbrev)
3477       llvm_unreachable("Unexpected abbrev ordering!");
3478   }
3479   { // NULL abbrev for CONSTANTS_BLOCK.
3480     auto Abbv = std::make_shared<BitCodeAbbrev>();
3481     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
3482     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3483         CONSTANTS_NULL_Abbrev)
3484       llvm_unreachable("Unexpected abbrev ordering!");
3485   }
3486 
3487   // FIXME: This should only use space for first class types!
3488 
3489   { // INST_LOAD abbrev for FUNCTION_BLOCK.
3490     auto Abbv = std::make_shared<BitCodeAbbrev>();
3491     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
3492     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
3493     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
3494                               VE.computeBitsRequiredForTypeIndicies()));
3495     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
3496     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
3497     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3498         FUNCTION_INST_LOAD_ABBREV)
3499       llvm_unreachable("Unexpected abbrev ordering!");
3500   }
3501   { // INST_UNOP abbrev for FUNCTION_BLOCK.
3502     auto Abbv = std::make_shared<BitCodeAbbrev>();
3503     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3504     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3505     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3506     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3507         FUNCTION_INST_UNOP_ABBREV)
3508       llvm_unreachable("Unexpected abbrev ordering!");
3509   }
3510   { // INST_UNOP_FLAGS abbrev for FUNCTION_BLOCK.
3511     auto Abbv = std::make_shared<BitCodeAbbrev>();
3512     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3513     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3514     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3515     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3516     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3517         FUNCTION_INST_UNOP_FLAGS_ABBREV)
3518       llvm_unreachable("Unexpected abbrev ordering!");
3519   }
3520   { // INST_BINOP abbrev for FUNCTION_BLOCK.
3521     auto Abbv = std::make_shared<BitCodeAbbrev>();
3522     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3523     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3524     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3525     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3526     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3527         FUNCTION_INST_BINOP_ABBREV)
3528       llvm_unreachable("Unexpected abbrev ordering!");
3529   }
3530   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
3531     auto Abbv = std::make_shared<BitCodeAbbrev>();
3532     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3533     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3534     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3535     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3536     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3537     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3538         FUNCTION_INST_BINOP_FLAGS_ABBREV)
3539       llvm_unreachable("Unexpected abbrev ordering!");
3540   }
3541   { // INST_CAST abbrev for FUNCTION_BLOCK.
3542     auto Abbv = std::make_shared<BitCodeAbbrev>();
3543     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
3544     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
3545     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
3546                               VE.computeBitsRequiredForTypeIndicies()));
3547     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
3548     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3549         FUNCTION_INST_CAST_ABBREV)
3550       llvm_unreachable("Unexpected abbrev ordering!");
3551   }
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     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3557         FUNCTION_INST_RET_VOID_ABBREV)
3558       llvm_unreachable("Unexpected abbrev ordering!");
3559   }
3560   { // INST_RET abbrev for FUNCTION_BLOCK.
3561     auto Abbv = std::make_shared<BitCodeAbbrev>();
3562     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3563     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
3564     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3565         FUNCTION_INST_RET_VAL_ABBREV)
3566       llvm_unreachable("Unexpected abbrev ordering!");
3567   }
3568   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
3569     auto Abbv = std::make_shared<BitCodeAbbrev>();
3570     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
3571     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3572         FUNCTION_INST_UNREACHABLE_ABBREV)
3573       llvm_unreachable("Unexpected abbrev ordering!");
3574   }
3575   {
3576     auto Abbv = std::make_shared<BitCodeAbbrev>();
3577     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_GEP));
3578     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
3579     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, // dest ty
3580                               Log2_32_Ceil(VE.getTypes().size() + 1)));
3581     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3582     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
3583     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3584         FUNCTION_INST_GEP_ABBREV)
3585       llvm_unreachable("Unexpected abbrev ordering!");
3586   }
3587 
3588   Stream.ExitBlock();
3589 }
3590 
3591 /// Write the module path strings, currently only used when generating
3592 /// a combined index file.
3593 void IndexBitcodeWriter::writeModStrings() {
3594   Stream.EnterSubblock(bitc::MODULE_STRTAB_BLOCK_ID, 3);
3595 
3596   // TODO: See which abbrev sizes we actually need to emit
3597 
3598   // 8-bit fixed-width MST_ENTRY strings.
3599   auto Abbv = std::make_shared<BitCodeAbbrev>();
3600   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3601   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3602   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3603   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3604   unsigned Abbrev8Bit = Stream.EmitAbbrev(std::move(Abbv));
3605 
3606   // 7-bit fixed width MST_ENTRY strings.
3607   Abbv = std::make_shared<BitCodeAbbrev>();
3608   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3609   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3610   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3611   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3612   unsigned Abbrev7Bit = Stream.EmitAbbrev(std::move(Abbv));
3613 
3614   // 6-bit char6 MST_ENTRY strings.
3615   Abbv = std::make_shared<BitCodeAbbrev>();
3616   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3617   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3618   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3619   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3620   unsigned Abbrev6Bit = Stream.EmitAbbrev(std::move(Abbv));
3621 
3622   // Module Hash, 160 bits SHA1. Optionally, emitted after each MST_CODE_ENTRY.
3623   Abbv = std::make_shared<BitCodeAbbrev>();
3624   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_HASH));
3625   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3626   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3627   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3628   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3629   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3630   unsigned AbbrevHash = Stream.EmitAbbrev(std::move(Abbv));
3631 
3632   SmallVector<unsigned, 64> Vals;
3633   forEachModule(
3634       [&](const StringMapEntry<std::pair<uint64_t, ModuleHash>> &MPSE) {
3635         StringRef Key = MPSE.getKey();
3636         const auto &Value = MPSE.getValue();
3637         StringEncoding Bits = getStringEncoding(Key);
3638         unsigned AbbrevToUse = Abbrev8Bit;
3639         if (Bits == SE_Char6)
3640           AbbrevToUse = Abbrev6Bit;
3641         else if (Bits == SE_Fixed7)
3642           AbbrevToUse = Abbrev7Bit;
3643 
3644         Vals.push_back(Value.first);
3645         Vals.append(Key.begin(), Key.end());
3646 
3647         // Emit the finished record.
3648         Stream.EmitRecord(bitc::MST_CODE_ENTRY, Vals, AbbrevToUse);
3649 
3650         // Emit an optional hash for the module now
3651         const auto &Hash = Value.second;
3652         if (llvm::any_of(Hash, [](uint32_t H) { return H; })) {
3653           Vals.assign(Hash.begin(), Hash.end());
3654           // Emit the hash record.
3655           Stream.EmitRecord(bitc::MST_CODE_HASH, Vals, AbbrevHash);
3656         }
3657 
3658         Vals.clear();
3659       });
3660   Stream.ExitBlock();
3661 }
3662 
3663 /// Write the function type metadata related records that need to appear before
3664 /// a function summary entry (whether per-module or combined).
3665 template <typename Fn>
3666 static void writeFunctionTypeMetadataRecords(BitstreamWriter &Stream,
3667                                              FunctionSummary *FS,
3668                                              Fn GetValueID) {
3669   if (!FS->type_tests().empty())
3670     Stream.EmitRecord(bitc::FS_TYPE_TESTS, FS->type_tests());
3671 
3672   SmallVector<uint64_t, 64> Record;
3673 
3674   auto WriteVFuncIdVec = [&](uint64_t Ty,
3675                              ArrayRef<FunctionSummary::VFuncId> VFs) {
3676     if (VFs.empty())
3677       return;
3678     Record.clear();
3679     for (auto &VF : VFs) {
3680       Record.push_back(VF.GUID);
3681       Record.push_back(VF.Offset);
3682     }
3683     Stream.EmitRecord(Ty, Record);
3684   };
3685 
3686   WriteVFuncIdVec(bitc::FS_TYPE_TEST_ASSUME_VCALLS,
3687                   FS->type_test_assume_vcalls());
3688   WriteVFuncIdVec(bitc::FS_TYPE_CHECKED_LOAD_VCALLS,
3689                   FS->type_checked_load_vcalls());
3690 
3691   auto WriteConstVCallVec = [&](uint64_t Ty,
3692                                 ArrayRef<FunctionSummary::ConstVCall> VCs) {
3693     for (auto &VC : VCs) {
3694       Record.clear();
3695       Record.push_back(VC.VFunc.GUID);
3696       Record.push_back(VC.VFunc.Offset);
3697       llvm::append_range(Record, VC.Args);
3698       Stream.EmitRecord(Ty, Record);
3699     }
3700   };
3701 
3702   WriteConstVCallVec(bitc::FS_TYPE_TEST_ASSUME_CONST_VCALL,
3703                      FS->type_test_assume_const_vcalls());
3704   WriteConstVCallVec(bitc::FS_TYPE_CHECKED_LOAD_CONST_VCALL,
3705                      FS->type_checked_load_const_vcalls());
3706 
3707   auto WriteRange = [&](ConstantRange Range) {
3708     Range = Range.sextOrTrunc(FunctionSummary::ParamAccess::RangeWidth);
3709     assert(Range.getLower().getNumWords() == 1);
3710     assert(Range.getUpper().getNumWords() == 1);
3711     emitSignedInt64(Record, *Range.getLower().getRawData());
3712     emitSignedInt64(Record, *Range.getUpper().getRawData());
3713   };
3714 
3715   if (!FS->paramAccesses().empty()) {
3716     Record.clear();
3717     for (auto &Arg : FS->paramAccesses()) {
3718       size_t UndoSize = Record.size();
3719       Record.push_back(Arg.ParamNo);
3720       WriteRange(Arg.Use);
3721       Record.push_back(Arg.Calls.size());
3722       for (auto &Call : Arg.Calls) {
3723         Record.push_back(Call.ParamNo);
3724         Optional<unsigned> ValueID = GetValueID(Call.Callee);
3725         if (!ValueID) {
3726           // If ValueID is unknown we can't drop just this call, we must drop
3727           // entire parameter.
3728           Record.resize(UndoSize);
3729           break;
3730         }
3731         Record.push_back(*ValueID);
3732         WriteRange(Call.Offsets);
3733       }
3734     }
3735     if (!Record.empty())
3736       Stream.EmitRecord(bitc::FS_PARAM_ACCESS, Record);
3737   }
3738 }
3739 
3740 /// Collect type IDs from type tests used by function.
3741 static void
3742 getReferencedTypeIds(FunctionSummary *FS,
3743                      std::set<GlobalValue::GUID> &ReferencedTypeIds) {
3744   if (!FS->type_tests().empty())
3745     for (auto &TT : FS->type_tests())
3746       ReferencedTypeIds.insert(TT);
3747 
3748   auto GetReferencedTypesFromVFuncIdVec =
3749       [&](ArrayRef<FunctionSummary::VFuncId> VFs) {
3750         for (auto &VF : VFs)
3751           ReferencedTypeIds.insert(VF.GUID);
3752       };
3753 
3754   GetReferencedTypesFromVFuncIdVec(FS->type_test_assume_vcalls());
3755   GetReferencedTypesFromVFuncIdVec(FS->type_checked_load_vcalls());
3756 
3757   auto GetReferencedTypesFromConstVCallVec =
3758       [&](ArrayRef<FunctionSummary::ConstVCall> VCs) {
3759         for (auto &VC : VCs)
3760           ReferencedTypeIds.insert(VC.VFunc.GUID);
3761       };
3762 
3763   GetReferencedTypesFromConstVCallVec(FS->type_test_assume_const_vcalls());
3764   GetReferencedTypesFromConstVCallVec(FS->type_checked_load_const_vcalls());
3765 }
3766 
3767 static void writeWholeProgramDevirtResolutionByArg(
3768     SmallVector<uint64_t, 64> &NameVals, const std::vector<uint64_t> &args,
3769     const WholeProgramDevirtResolution::ByArg &ByArg) {
3770   NameVals.push_back(args.size());
3771   llvm::append_range(NameVals, args);
3772 
3773   NameVals.push_back(ByArg.TheKind);
3774   NameVals.push_back(ByArg.Info);
3775   NameVals.push_back(ByArg.Byte);
3776   NameVals.push_back(ByArg.Bit);
3777 }
3778 
3779 static void writeWholeProgramDevirtResolution(
3780     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3781     uint64_t Id, const WholeProgramDevirtResolution &Wpd) {
3782   NameVals.push_back(Id);
3783 
3784   NameVals.push_back(Wpd.TheKind);
3785   NameVals.push_back(StrtabBuilder.add(Wpd.SingleImplName));
3786   NameVals.push_back(Wpd.SingleImplName.size());
3787 
3788   NameVals.push_back(Wpd.ResByArg.size());
3789   for (auto &A : Wpd.ResByArg)
3790     writeWholeProgramDevirtResolutionByArg(NameVals, A.first, A.second);
3791 }
3792 
3793 static void writeTypeIdSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
3794                                      StringTableBuilder &StrtabBuilder,
3795                                      const std::string &Id,
3796                                      const TypeIdSummary &Summary) {
3797   NameVals.push_back(StrtabBuilder.add(Id));
3798   NameVals.push_back(Id.size());
3799 
3800   NameVals.push_back(Summary.TTRes.TheKind);
3801   NameVals.push_back(Summary.TTRes.SizeM1BitWidth);
3802   NameVals.push_back(Summary.TTRes.AlignLog2);
3803   NameVals.push_back(Summary.TTRes.SizeM1);
3804   NameVals.push_back(Summary.TTRes.BitMask);
3805   NameVals.push_back(Summary.TTRes.InlineBits);
3806 
3807   for (auto &W : Summary.WPDRes)
3808     writeWholeProgramDevirtResolution(NameVals, StrtabBuilder, W.first,
3809                                       W.second);
3810 }
3811 
3812 static void writeTypeIdCompatibleVtableSummaryRecord(
3813     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3814     const std::string &Id, const TypeIdCompatibleVtableInfo &Summary,
3815     ValueEnumerator &VE) {
3816   NameVals.push_back(StrtabBuilder.add(Id));
3817   NameVals.push_back(Id.size());
3818 
3819   for (auto &P : Summary) {
3820     NameVals.push_back(P.AddressPointOffset);
3821     NameVals.push_back(VE.getValueID(P.VTableVI.getValue()));
3822   }
3823 }
3824 
3825 // Helper to emit a single function summary record.
3826 void ModuleBitcodeWriterBase::writePerModuleFunctionSummaryRecord(
3827     SmallVector<uint64_t, 64> &NameVals, GlobalValueSummary *Summary,
3828     unsigned ValueID, unsigned FSCallsAbbrev, unsigned FSCallsProfileAbbrev,
3829     const Function &F) {
3830   NameVals.push_back(ValueID);
3831 
3832   FunctionSummary *FS = cast<FunctionSummary>(Summary);
3833 
3834   writeFunctionTypeMetadataRecords(
3835       Stream, FS, [&](const ValueInfo &VI) -> Optional<unsigned> {
3836         return {VE.getValueID(VI.getValue())};
3837       });
3838 
3839   auto SpecialRefCnts = FS->specialRefCounts();
3840   NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
3841   NameVals.push_back(FS->instCount());
3842   NameVals.push_back(getEncodedFFlags(FS->fflags()));
3843   NameVals.push_back(FS->refs().size());
3844   NameVals.push_back(SpecialRefCnts.first);  // rorefcnt
3845   NameVals.push_back(SpecialRefCnts.second); // worefcnt
3846 
3847   for (auto &RI : FS->refs())
3848     NameVals.push_back(VE.getValueID(RI.getValue()));
3849 
3850   bool HasProfileData =
3851       F.hasProfileData() || ForceSummaryEdgesCold != FunctionSummary::FSHT_None;
3852   for (auto &ECI : FS->calls()) {
3853     NameVals.push_back(getValueId(ECI.first));
3854     if (HasProfileData)
3855       NameVals.push_back(static_cast<uint8_t>(ECI.second.Hotness));
3856     else if (WriteRelBFToSummary)
3857       NameVals.push_back(ECI.second.RelBlockFreq);
3858   }
3859 
3860   unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
3861   unsigned Code =
3862       (HasProfileData ? bitc::FS_PERMODULE_PROFILE
3863                       : (WriteRelBFToSummary ? bitc::FS_PERMODULE_RELBF
3864                                              : bitc::FS_PERMODULE));
3865 
3866   // Emit the finished record.
3867   Stream.EmitRecord(Code, NameVals, FSAbbrev);
3868   NameVals.clear();
3869 }
3870 
3871 // Collect the global value references in the given variable's initializer,
3872 // and emit them in a summary record.
3873 void ModuleBitcodeWriterBase::writeModuleLevelReferences(
3874     const GlobalVariable &V, SmallVector<uint64_t, 64> &NameVals,
3875     unsigned FSModRefsAbbrev, unsigned FSModVTableRefsAbbrev) {
3876   auto VI = Index->getValueInfo(V.getGUID());
3877   if (!VI || VI.getSummaryList().empty()) {
3878     // Only declarations should not have a summary (a declaration might however
3879     // have a summary if the def was in module level asm).
3880     assert(V.isDeclaration());
3881     return;
3882   }
3883   auto *Summary = VI.getSummaryList()[0].get();
3884   NameVals.push_back(VE.getValueID(&V));
3885   GlobalVarSummary *VS = cast<GlobalVarSummary>(Summary);
3886   NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
3887   NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
3888 
3889   auto VTableFuncs = VS->vTableFuncs();
3890   if (!VTableFuncs.empty())
3891     NameVals.push_back(VS->refs().size());
3892 
3893   unsigned SizeBeforeRefs = NameVals.size();
3894   for (auto &RI : VS->refs())
3895     NameVals.push_back(VE.getValueID(RI.getValue()));
3896   // Sort the refs for determinism output, the vector returned by FS->refs() has
3897   // been initialized from a DenseSet.
3898   llvm::sort(drop_begin(NameVals, SizeBeforeRefs));
3899 
3900   if (VTableFuncs.empty())
3901     Stream.EmitRecord(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS, NameVals,
3902                       FSModRefsAbbrev);
3903   else {
3904     // VTableFuncs pairs should already be sorted by offset.
3905     for (auto &P : VTableFuncs) {
3906       NameVals.push_back(VE.getValueID(P.FuncVI.getValue()));
3907       NameVals.push_back(P.VTableOffset);
3908     }
3909 
3910     Stream.EmitRecord(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS, NameVals,
3911                       FSModVTableRefsAbbrev);
3912   }
3913   NameVals.clear();
3914 }
3915 
3916 /// Emit the per-module summary section alongside the rest of
3917 /// the module's bitcode.
3918 void ModuleBitcodeWriterBase::writePerModuleGlobalValueSummary() {
3919   // By default we compile with ThinLTO if the module has a summary, but the
3920   // client can request full LTO with a module flag.
3921   bool IsThinLTO = true;
3922   if (auto *MD =
3923           mdconst::extract_or_null<ConstantInt>(M.getModuleFlag("ThinLTO")))
3924     IsThinLTO = MD->getZExtValue();
3925   Stream.EnterSubblock(IsThinLTO ? bitc::GLOBALVAL_SUMMARY_BLOCK_ID
3926                                  : bitc::FULL_LTO_GLOBALVAL_SUMMARY_BLOCK_ID,
3927                        4);
3928 
3929   Stream.EmitRecord(
3930       bitc::FS_VERSION,
3931       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
3932 
3933   // Write the index flags.
3934   uint64_t Flags = 0;
3935   // Bits 1-3 are set only in the combined index, skip them.
3936   if (Index->enableSplitLTOUnit())
3937     Flags |= 0x8;
3938   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Flags});
3939 
3940   if (Index->begin() == Index->end()) {
3941     Stream.ExitBlock();
3942     return;
3943   }
3944 
3945   for (const auto &GVI : valueIds()) {
3946     Stream.EmitRecord(bitc::FS_VALUE_GUID,
3947                       ArrayRef<uint64_t>{GVI.second, GVI.first});
3948   }
3949 
3950   // Abbrev for FS_PERMODULE_PROFILE.
3951   auto Abbv = std::make_shared<BitCodeAbbrev>();
3952   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_PROFILE));
3953   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3954   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3955   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3956   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3957   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3958   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
3959   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
3960   // numrefs x valueid, n x (valueid, hotness)
3961   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3962   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3963   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3964 
3965   // Abbrev for FS_PERMODULE or FS_PERMODULE_RELBF.
3966   Abbv = std::make_shared<BitCodeAbbrev>();
3967   if (WriteRelBFToSummary)
3968     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_RELBF));
3969   else
3970     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE));
3971   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3972   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3973   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3974   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3975   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3976   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
3977   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
3978   // numrefs x valueid, n x (valueid [, rel_block_freq])
3979   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3980   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3981   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3982 
3983   // Abbrev for FS_PERMODULE_GLOBALVAR_INIT_REFS.
3984   Abbv = std::make_shared<BitCodeAbbrev>();
3985   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS));
3986   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
3987   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
3988   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));  // valueids
3989   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3990   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3991 
3992   // Abbrev for FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS.
3993   Abbv = std::make_shared<BitCodeAbbrev>();
3994   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS));
3995   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
3996   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
3997   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numrefs
3998   // numrefs x valueid, n x (valueid , offset)
3999   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4000   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4001   unsigned FSModVTableRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4002 
4003   // Abbrev for FS_ALIAS.
4004   Abbv = std::make_shared<BitCodeAbbrev>();
4005   Abbv->Add(BitCodeAbbrevOp(bitc::FS_ALIAS));
4006   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4007   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4008   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4009   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4010 
4011   // Abbrev for FS_TYPE_ID_METADATA
4012   Abbv = std::make_shared<BitCodeAbbrev>();
4013   Abbv->Add(BitCodeAbbrevOp(bitc::FS_TYPE_ID_METADATA));
4014   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid strtab index
4015   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid length
4016   // n x (valueid , offset)
4017   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4018   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4019   unsigned TypeIdCompatibleVtableAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4020 
4021   SmallVector<uint64_t, 64> NameVals;
4022   // Iterate over the list of functions instead of the Index to
4023   // ensure the ordering is stable.
4024   for (const Function &F : M) {
4025     // Summary emission does not support anonymous functions, they have to
4026     // renamed using the anonymous function renaming pass.
4027     if (!F.hasName())
4028       report_fatal_error("Unexpected anonymous function when writing summary");
4029 
4030     ValueInfo VI = Index->getValueInfo(F.getGUID());
4031     if (!VI || VI.getSummaryList().empty()) {
4032       // Only declarations should not have a summary (a declaration might
4033       // however have a summary if the def was in module level asm).
4034       assert(F.isDeclaration());
4035       continue;
4036     }
4037     auto *Summary = VI.getSummaryList()[0].get();
4038     writePerModuleFunctionSummaryRecord(NameVals, Summary, VE.getValueID(&F),
4039                                         FSCallsAbbrev, FSCallsProfileAbbrev, F);
4040   }
4041 
4042   // Capture references from GlobalVariable initializers, which are outside
4043   // of a function scope.
4044   for (const GlobalVariable &G : M.globals())
4045     writeModuleLevelReferences(G, NameVals, FSModRefsAbbrev,
4046                                FSModVTableRefsAbbrev);
4047 
4048   for (const GlobalAlias &A : M.aliases()) {
4049     auto *Aliasee = A.getAliaseeObject();
4050     if (!Aliasee->hasName())
4051       // Nameless function don't have an entry in the summary, skip it.
4052       continue;
4053     auto AliasId = VE.getValueID(&A);
4054     auto AliaseeId = VE.getValueID(Aliasee);
4055     NameVals.push_back(AliasId);
4056     auto *Summary = Index->getGlobalValueSummary(A);
4057     AliasSummary *AS = cast<AliasSummary>(Summary);
4058     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
4059     NameVals.push_back(AliaseeId);
4060     Stream.EmitRecord(bitc::FS_ALIAS, NameVals, FSAliasAbbrev);
4061     NameVals.clear();
4062   }
4063 
4064   for (auto &S : Index->typeIdCompatibleVtableMap()) {
4065     writeTypeIdCompatibleVtableSummaryRecord(NameVals, StrtabBuilder, S.first,
4066                                              S.second, VE);
4067     Stream.EmitRecord(bitc::FS_TYPE_ID_METADATA, NameVals,
4068                       TypeIdCompatibleVtableAbbrev);
4069     NameVals.clear();
4070   }
4071 
4072   Stream.EmitRecord(bitc::FS_BLOCK_COUNT,
4073                     ArrayRef<uint64_t>{Index->getBlockCount()});
4074 
4075   Stream.ExitBlock();
4076 }
4077 
4078 /// Emit the combined summary section into the combined index file.
4079 void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
4080   Stream.EnterSubblock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID, 3);
4081   Stream.EmitRecord(
4082       bitc::FS_VERSION,
4083       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
4084 
4085   // Write the index flags.
4086   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Index.getFlags()});
4087 
4088   for (const auto &GVI : valueIds()) {
4089     Stream.EmitRecord(bitc::FS_VALUE_GUID,
4090                       ArrayRef<uint64_t>{GVI.second, GVI.first});
4091   }
4092 
4093   // Abbrev for FS_COMBINED.
4094   auto Abbv = std::make_shared<BitCodeAbbrev>();
4095   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED));
4096   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4097   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4098   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4099   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4100   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4101   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
4102   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4103   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4104   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4105   // numrefs x valueid, n x (valueid)
4106   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4107   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4108   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4109 
4110   // Abbrev for FS_COMBINED_PROFILE.
4111   Abbv = std::make_shared<BitCodeAbbrev>();
4112   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_PROFILE));
4113   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4114   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4115   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4116   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4117   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4118   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
4119   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4120   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4121   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4122   // numrefs x valueid, n x (valueid, hotness)
4123   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4124   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4125   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4126 
4127   // Abbrev for FS_COMBINED_GLOBALVAR_INIT_REFS.
4128   Abbv = std::make_shared<BitCodeAbbrev>();
4129   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS));
4130   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4131   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4132   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4133   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));    // valueids
4134   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4135   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4136 
4137   // Abbrev for FS_COMBINED_ALIAS.
4138   Abbv = std::make_shared<BitCodeAbbrev>();
4139   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_ALIAS));
4140   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4141   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4142   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4143   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4144   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4145 
4146   // The aliases are emitted as a post-pass, and will point to the value
4147   // id of the aliasee. Save them in a vector for post-processing.
4148   SmallVector<AliasSummary *, 64> Aliases;
4149 
4150   // Save the value id for each summary for alias emission.
4151   DenseMap<const GlobalValueSummary *, unsigned> SummaryToValueIdMap;
4152 
4153   SmallVector<uint64_t, 64> NameVals;
4154 
4155   // Set that will be populated during call to writeFunctionTypeMetadataRecords
4156   // with the type ids referenced by this index file.
4157   std::set<GlobalValue::GUID> ReferencedTypeIds;
4158 
4159   // For local linkage, we also emit the original name separately
4160   // immediately after the record.
4161   auto MaybeEmitOriginalName = [&](GlobalValueSummary &S) {
4162     // We don't need to emit the original name if we are writing the index for
4163     // distributed backends (in which case ModuleToSummariesForIndex is
4164     // non-null). The original name is only needed during the thin link, since
4165     // for SamplePGO the indirect call targets for local functions have
4166     // have the original name annotated in profile.
4167     // Continue to emit it when writing out the entire combined index, which is
4168     // used in testing the thin link via llvm-lto.
4169     if (ModuleToSummariesForIndex || !GlobalValue::isLocalLinkage(S.linkage()))
4170       return;
4171     NameVals.push_back(S.getOriginalName());
4172     Stream.EmitRecord(bitc::FS_COMBINED_ORIGINAL_NAME, NameVals);
4173     NameVals.clear();
4174   };
4175 
4176   std::set<GlobalValue::GUID> DefOrUseGUIDs;
4177   forEachSummary([&](GVInfo I, bool IsAliasee) {
4178     GlobalValueSummary *S = I.second;
4179     assert(S);
4180     DefOrUseGUIDs.insert(I.first);
4181     for (const ValueInfo &VI : S->refs())
4182       DefOrUseGUIDs.insert(VI.getGUID());
4183 
4184     auto ValueId = getValueId(I.first);
4185     assert(ValueId);
4186     SummaryToValueIdMap[S] = *ValueId;
4187 
4188     // If this is invoked for an aliasee, we want to record the above
4189     // mapping, but then not emit a summary entry (if the aliasee is
4190     // to be imported, we will invoke this separately with IsAliasee=false).
4191     if (IsAliasee)
4192       return;
4193 
4194     if (auto *AS = dyn_cast<AliasSummary>(S)) {
4195       // Will process aliases as a post-pass because the reader wants all
4196       // global to be loaded first.
4197       Aliases.push_back(AS);
4198       return;
4199     }
4200 
4201     if (auto *VS = dyn_cast<GlobalVarSummary>(S)) {
4202       NameVals.push_back(*ValueId);
4203       NameVals.push_back(Index.getModuleId(VS->modulePath()));
4204       NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
4205       NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
4206       for (auto &RI : VS->refs()) {
4207         auto RefValueId = getValueId(RI.getGUID());
4208         if (!RefValueId)
4209           continue;
4210         NameVals.push_back(*RefValueId);
4211       }
4212 
4213       // Emit the finished record.
4214       Stream.EmitRecord(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS, NameVals,
4215                         FSModRefsAbbrev);
4216       NameVals.clear();
4217       MaybeEmitOriginalName(*S);
4218       return;
4219     }
4220 
4221     auto GetValueId = [&](const ValueInfo &VI) -> Optional<unsigned> {
4222       return getValueId(VI.getGUID());
4223     };
4224 
4225     auto *FS = cast<FunctionSummary>(S);
4226     writeFunctionTypeMetadataRecords(Stream, FS, GetValueId);
4227     getReferencedTypeIds(FS, ReferencedTypeIds);
4228 
4229     NameVals.push_back(*ValueId);
4230     NameVals.push_back(Index.getModuleId(FS->modulePath()));
4231     NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
4232     NameVals.push_back(FS->instCount());
4233     NameVals.push_back(getEncodedFFlags(FS->fflags()));
4234     NameVals.push_back(FS->entryCount());
4235 
4236     // Fill in below
4237     NameVals.push_back(0); // numrefs
4238     NameVals.push_back(0); // rorefcnt
4239     NameVals.push_back(0); // worefcnt
4240 
4241     unsigned Count = 0, RORefCnt = 0, WORefCnt = 0;
4242     for (auto &RI : FS->refs()) {
4243       auto RefValueId = getValueId(RI.getGUID());
4244       if (!RefValueId)
4245         continue;
4246       NameVals.push_back(*RefValueId);
4247       if (RI.isReadOnly())
4248         RORefCnt++;
4249       else if (RI.isWriteOnly())
4250         WORefCnt++;
4251       Count++;
4252     }
4253     NameVals[6] = Count;
4254     NameVals[7] = RORefCnt;
4255     NameVals[8] = WORefCnt;
4256 
4257     bool HasProfileData = false;
4258     for (auto &EI : FS->calls()) {
4259       HasProfileData |=
4260           EI.second.getHotness() != CalleeInfo::HotnessType::Unknown;
4261       if (HasProfileData)
4262         break;
4263     }
4264 
4265     for (auto &EI : FS->calls()) {
4266       // If this GUID doesn't have a value id, it doesn't have a function
4267       // summary and we don't need to record any calls to it.
4268       Optional<unsigned> CallValueId = GetValueId(EI.first);
4269       if (!CallValueId)
4270         continue;
4271       NameVals.push_back(*CallValueId);
4272       if (HasProfileData)
4273         NameVals.push_back(static_cast<uint8_t>(EI.second.Hotness));
4274     }
4275 
4276     unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
4277     unsigned Code =
4278         (HasProfileData ? bitc::FS_COMBINED_PROFILE : bitc::FS_COMBINED);
4279 
4280     // Emit the finished record.
4281     Stream.EmitRecord(Code, NameVals, FSAbbrev);
4282     NameVals.clear();
4283     MaybeEmitOriginalName(*S);
4284   });
4285 
4286   for (auto *AS : Aliases) {
4287     auto AliasValueId = SummaryToValueIdMap[AS];
4288     assert(AliasValueId);
4289     NameVals.push_back(AliasValueId);
4290     NameVals.push_back(Index.getModuleId(AS->modulePath()));
4291     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
4292     auto AliaseeValueId = SummaryToValueIdMap[&AS->getAliasee()];
4293     assert(AliaseeValueId);
4294     NameVals.push_back(AliaseeValueId);
4295 
4296     // Emit the finished record.
4297     Stream.EmitRecord(bitc::FS_COMBINED_ALIAS, NameVals, FSAliasAbbrev);
4298     NameVals.clear();
4299     MaybeEmitOriginalName(*AS);
4300 
4301     if (auto *FS = dyn_cast<FunctionSummary>(&AS->getAliasee()))
4302       getReferencedTypeIds(FS, ReferencedTypeIds);
4303   }
4304 
4305   if (!Index.cfiFunctionDefs().empty()) {
4306     for (auto &S : Index.cfiFunctionDefs()) {
4307       if (DefOrUseGUIDs.count(
4308               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4309         NameVals.push_back(StrtabBuilder.add(S));
4310         NameVals.push_back(S.size());
4311       }
4312     }
4313     if (!NameVals.empty()) {
4314       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DEFS, NameVals);
4315       NameVals.clear();
4316     }
4317   }
4318 
4319   if (!Index.cfiFunctionDecls().empty()) {
4320     for (auto &S : Index.cfiFunctionDecls()) {
4321       if (DefOrUseGUIDs.count(
4322               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4323         NameVals.push_back(StrtabBuilder.add(S));
4324         NameVals.push_back(S.size());
4325       }
4326     }
4327     if (!NameVals.empty()) {
4328       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DECLS, NameVals);
4329       NameVals.clear();
4330     }
4331   }
4332 
4333   // Walk the GUIDs that were referenced, and write the
4334   // corresponding type id records.
4335   for (auto &T : ReferencedTypeIds) {
4336     auto TidIter = Index.typeIds().equal_range(T);
4337     for (auto It = TidIter.first; It != TidIter.second; ++It) {
4338       writeTypeIdSummaryRecord(NameVals, StrtabBuilder, It->second.first,
4339                                It->second.second);
4340       Stream.EmitRecord(bitc::FS_TYPE_ID, NameVals);
4341       NameVals.clear();
4342     }
4343   }
4344 
4345   Stream.EmitRecord(bitc::FS_BLOCK_COUNT,
4346                     ArrayRef<uint64_t>{Index.getBlockCount()});
4347 
4348   Stream.ExitBlock();
4349 }
4350 
4351 /// Create the "IDENTIFICATION_BLOCK_ID" containing a single string with the
4352 /// current llvm version, and a record for the epoch number.
4353 static void writeIdentificationBlock(BitstreamWriter &Stream) {
4354   Stream.EnterSubblock(bitc::IDENTIFICATION_BLOCK_ID, 5);
4355 
4356   // Write the "user readable" string identifying the bitcode producer
4357   auto Abbv = std::make_shared<BitCodeAbbrev>();
4358   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_STRING));
4359   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4360   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
4361   auto StringAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4362   writeStringRecord(Stream, bitc::IDENTIFICATION_CODE_STRING,
4363                     "LLVM" LLVM_VERSION_STRING, StringAbbrev);
4364 
4365   // Write the epoch version
4366   Abbv = std::make_shared<BitCodeAbbrev>();
4367   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_EPOCH));
4368   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
4369   auto EpochAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4370   constexpr std::array<unsigned, 1> Vals = {{bitc::BITCODE_CURRENT_EPOCH}};
4371   Stream.EmitRecord(bitc::IDENTIFICATION_CODE_EPOCH, Vals, EpochAbbrev);
4372   Stream.ExitBlock();
4373 }
4374 
4375 void ModuleBitcodeWriter::writeModuleHash(size_t BlockStartPos) {
4376   // Emit the module's hash.
4377   // MODULE_CODE_HASH: [5*i32]
4378   if (GenerateHash) {
4379     uint32_t Vals[5];
4380     Hasher.update(ArrayRef<uint8_t>((const uint8_t *)&(Buffer)[BlockStartPos],
4381                                     Buffer.size() - BlockStartPos));
4382     StringRef Hash = Hasher.result();
4383     for (int Pos = 0; Pos < 20; Pos += 4) {
4384       Vals[Pos / 4] = support::endian::read32be(Hash.data() + Pos);
4385     }
4386 
4387     // Emit the finished record.
4388     Stream.EmitRecord(bitc::MODULE_CODE_HASH, Vals);
4389 
4390     if (ModHash)
4391       // Save the written hash value.
4392       llvm::copy(Vals, std::begin(*ModHash));
4393   }
4394 }
4395 
4396 void ModuleBitcodeWriter::write() {
4397   writeIdentificationBlock(Stream);
4398 
4399   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4400   size_t BlockStartPos = Buffer.size();
4401 
4402   writeModuleVersion();
4403 
4404   // Emit blockinfo, which defines the standard abbreviations etc.
4405   writeBlockInfo();
4406 
4407   // Emit information describing all of the types in the module.
4408   writeTypeTable();
4409 
4410   // Emit information about attribute groups.
4411   writeAttributeGroupTable();
4412 
4413   // Emit information about parameter attributes.
4414   writeAttributeTable();
4415 
4416   writeComdats();
4417 
4418   // Emit top-level description of module, including target triple, inline asm,
4419   // descriptors for global variables, and function prototype info.
4420   writeModuleInfo();
4421 
4422   // Emit constants.
4423   writeModuleConstants();
4424 
4425   // Emit metadata kind names.
4426   writeModuleMetadataKinds();
4427 
4428   // Emit metadata.
4429   writeModuleMetadata();
4430 
4431   // Emit module-level use-lists.
4432   if (VE.shouldPreserveUseListOrder())
4433     writeUseListBlock(nullptr);
4434 
4435   writeOperandBundleTags();
4436   writeSyncScopeNames();
4437 
4438   // Emit function bodies.
4439   DenseMap<const Function *, uint64_t> FunctionToBitcodeIndex;
4440   for (const Function &F : M)
4441     if (!F.isDeclaration())
4442       writeFunction(F, FunctionToBitcodeIndex);
4443 
4444   // Need to write after the above call to WriteFunction which populates
4445   // the summary information in the index.
4446   if (Index)
4447     writePerModuleGlobalValueSummary();
4448 
4449   writeGlobalValueSymbolTable(FunctionToBitcodeIndex);
4450 
4451   writeModuleHash(BlockStartPos);
4452 
4453   Stream.ExitBlock();
4454 }
4455 
4456 static void writeInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
4457                                uint32_t &Position) {
4458   support::endian::write32le(&Buffer[Position], Value);
4459   Position += 4;
4460 }
4461 
4462 /// If generating a bc file on darwin, we have to emit a
4463 /// header and trailer to make it compatible with the system archiver.  To do
4464 /// this we emit the following header, and then emit a trailer that pads the
4465 /// file out to be a multiple of 16 bytes.
4466 ///
4467 /// struct bc_header {
4468 ///   uint32_t Magic;         // 0x0B17C0DE
4469 ///   uint32_t Version;       // Version, currently always 0.
4470 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
4471 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
4472 ///   uint32_t CPUType;       // CPU specifier.
4473 ///   ... potentially more later ...
4474 /// };
4475 static void emitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
4476                                          const Triple &TT) {
4477   unsigned CPUType = ~0U;
4478 
4479   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
4480   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
4481   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
4482   // specific constants here because they are implicitly part of the Darwin ABI.
4483   enum {
4484     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
4485     DARWIN_CPU_TYPE_X86        = 7,
4486     DARWIN_CPU_TYPE_ARM        = 12,
4487     DARWIN_CPU_TYPE_POWERPC    = 18
4488   };
4489 
4490   Triple::ArchType Arch = TT.getArch();
4491   if (Arch == Triple::x86_64)
4492     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
4493   else if (Arch == Triple::x86)
4494     CPUType = DARWIN_CPU_TYPE_X86;
4495   else if (Arch == Triple::ppc)
4496     CPUType = DARWIN_CPU_TYPE_POWERPC;
4497   else if (Arch == Triple::ppc64)
4498     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
4499   else if (Arch == Triple::arm || Arch == Triple::thumb)
4500     CPUType = DARWIN_CPU_TYPE_ARM;
4501 
4502   // Traditional Bitcode starts after header.
4503   assert(Buffer.size() >= BWH_HeaderSize &&
4504          "Expected header size to be reserved");
4505   unsigned BCOffset = BWH_HeaderSize;
4506   unsigned BCSize = Buffer.size() - BWH_HeaderSize;
4507 
4508   // Write the magic and version.
4509   unsigned Position = 0;
4510   writeInt32ToBuffer(0x0B17C0DE, Buffer, Position);
4511   writeInt32ToBuffer(0, Buffer, Position); // Version.
4512   writeInt32ToBuffer(BCOffset, Buffer, Position);
4513   writeInt32ToBuffer(BCSize, Buffer, Position);
4514   writeInt32ToBuffer(CPUType, Buffer, Position);
4515 
4516   // If the file is not a multiple of 16 bytes, insert dummy padding.
4517   while (Buffer.size() & 15)
4518     Buffer.push_back(0);
4519 }
4520 
4521 /// Helper to write the header common to all bitcode files.
4522 static void writeBitcodeHeader(BitstreamWriter &Stream) {
4523   // Emit the file header.
4524   Stream.Emit((unsigned)'B', 8);
4525   Stream.Emit((unsigned)'C', 8);
4526   Stream.Emit(0x0, 4);
4527   Stream.Emit(0xC, 4);
4528   Stream.Emit(0xE, 4);
4529   Stream.Emit(0xD, 4);
4530 }
4531 
4532 BitcodeWriter::BitcodeWriter(SmallVectorImpl<char> &Buffer, raw_fd_stream *FS)
4533     : Buffer(Buffer), Stream(new BitstreamWriter(Buffer, FS, FlushThreshold)) {
4534   writeBitcodeHeader(*Stream);
4535 }
4536 
4537 BitcodeWriter::~BitcodeWriter() { assert(WroteStrtab); }
4538 
4539 void BitcodeWriter::writeBlob(unsigned Block, unsigned Record, StringRef Blob) {
4540   Stream->EnterSubblock(Block, 3);
4541 
4542   auto Abbv = std::make_shared<BitCodeAbbrev>();
4543   Abbv->Add(BitCodeAbbrevOp(Record));
4544   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
4545   auto AbbrevNo = Stream->EmitAbbrev(std::move(Abbv));
4546 
4547   Stream->EmitRecordWithBlob(AbbrevNo, ArrayRef<uint64_t>{Record}, Blob);
4548 
4549   Stream->ExitBlock();
4550 }
4551 
4552 void BitcodeWriter::writeSymtab() {
4553   assert(!WroteStrtab && !WroteSymtab);
4554 
4555   // If any module has module-level inline asm, we will require a registered asm
4556   // parser for the target so that we can create an accurate symbol table for
4557   // the module.
4558   for (Module *M : Mods) {
4559     if (M->getModuleInlineAsm().empty())
4560       continue;
4561 
4562     std::string Err;
4563     const Triple TT(M->getTargetTriple());
4564     const Target *T = TargetRegistry::lookupTarget(TT.str(), Err);
4565     if (!T || !T->hasMCAsmParser())
4566       return;
4567   }
4568 
4569   WroteSymtab = true;
4570   SmallVector<char, 0> Symtab;
4571   // The irsymtab::build function may be unable to create a symbol table if the
4572   // module is malformed (e.g. it contains an invalid alias). Writing a symbol
4573   // table is not required for correctness, but we still want to be able to
4574   // write malformed modules to bitcode files, so swallow the error.
4575   if (Error E = irsymtab::build(Mods, Symtab, StrtabBuilder, Alloc)) {
4576     consumeError(std::move(E));
4577     return;
4578   }
4579 
4580   writeBlob(bitc::SYMTAB_BLOCK_ID, bitc::SYMTAB_BLOB,
4581             {Symtab.data(), Symtab.size()});
4582 }
4583 
4584 void BitcodeWriter::writeStrtab() {
4585   assert(!WroteStrtab);
4586 
4587   std::vector<char> Strtab;
4588   StrtabBuilder.finalizeInOrder();
4589   Strtab.resize(StrtabBuilder.getSize());
4590   StrtabBuilder.write((uint8_t *)Strtab.data());
4591 
4592   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB,
4593             {Strtab.data(), Strtab.size()});
4594 
4595   WroteStrtab = true;
4596 }
4597 
4598 void BitcodeWriter::copyStrtab(StringRef Strtab) {
4599   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB, Strtab);
4600   WroteStrtab = true;
4601 }
4602 
4603 void BitcodeWriter::writeModule(const Module &M,
4604                                 bool ShouldPreserveUseListOrder,
4605                                 const ModuleSummaryIndex *Index,
4606                                 bool GenerateHash, ModuleHash *ModHash) {
4607   assert(!WroteStrtab);
4608 
4609   // The Mods vector is used by irsymtab::build, which requires non-const
4610   // Modules in case it needs to materialize metadata. But the bitcode writer
4611   // requires that the module is materialized, so we can cast to non-const here,
4612   // after checking that it is in fact materialized.
4613   assert(M.isMaterialized());
4614   Mods.push_back(const_cast<Module *>(&M));
4615 
4616   ModuleBitcodeWriter ModuleWriter(M, Buffer, StrtabBuilder, *Stream,
4617                                    ShouldPreserveUseListOrder, Index,
4618                                    GenerateHash, ModHash);
4619   ModuleWriter.write();
4620 }
4621 
4622 void BitcodeWriter::writeIndex(
4623     const ModuleSummaryIndex *Index,
4624     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4625   IndexBitcodeWriter IndexWriter(*Stream, StrtabBuilder, *Index,
4626                                  ModuleToSummariesForIndex);
4627   IndexWriter.write();
4628 }
4629 
4630 /// Write the specified module to the specified output stream.
4631 void llvm::WriteBitcodeToFile(const Module &M, raw_ostream &Out,
4632                               bool ShouldPreserveUseListOrder,
4633                               const ModuleSummaryIndex *Index,
4634                               bool GenerateHash, ModuleHash *ModHash) {
4635   SmallVector<char, 0> Buffer;
4636   Buffer.reserve(256*1024);
4637 
4638   // If this is darwin or another generic macho target, reserve space for the
4639   // header.
4640   Triple TT(M.getTargetTriple());
4641   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4642     Buffer.insert(Buffer.begin(), BWH_HeaderSize, 0);
4643 
4644   BitcodeWriter Writer(Buffer, dyn_cast<raw_fd_stream>(&Out));
4645   Writer.writeModule(M, ShouldPreserveUseListOrder, Index, GenerateHash,
4646                      ModHash);
4647   Writer.writeSymtab();
4648   Writer.writeStrtab();
4649 
4650   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4651     emitDarwinBCHeaderAndTrailer(Buffer, TT);
4652 
4653   // Write the generated bitstream to "Out".
4654   if (!Buffer.empty())
4655     Out.write((char *)&Buffer.front(), Buffer.size());
4656 }
4657 
4658 void IndexBitcodeWriter::write() {
4659   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4660 
4661   writeModuleVersion();
4662 
4663   // Write the module paths in the combined index.
4664   writeModStrings();
4665 
4666   // Write the summary combined index records.
4667   writeCombinedGlobalValueSummary();
4668 
4669   Stream.ExitBlock();
4670 }
4671 
4672 // Write the specified module summary index to the given raw output stream,
4673 // where it will be written in a new bitcode block. This is used when
4674 // writing the combined index file for ThinLTO. When writing a subset of the
4675 // index for a distributed backend, provide a \p ModuleToSummariesForIndex map.
4676 void llvm::writeIndexToFile(
4677     const ModuleSummaryIndex &Index, raw_ostream &Out,
4678     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4679   SmallVector<char, 0> Buffer;
4680   Buffer.reserve(256 * 1024);
4681 
4682   BitcodeWriter Writer(Buffer);
4683   Writer.writeIndex(&Index, ModuleToSummariesForIndex);
4684   Writer.writeStrtab();
4685 
4686   Out.write((char *)&Buffer.front(), Buffer.size());
4687 }
4688 
4689 namespace {
4690 
4691 /// Class to manage the bitcode writing for a thin link bitcode file.
4692 class ThinLinkBitcodeWriter : public ModuleBitcodeWriterBase {
4693   /// ModHash is for use in ThinLTO incremental build, generated while writing
4694   /// the module bitcode file.
4695   const ModuleHash *ModHash;
4696 
4697 public:
4698   ThinLinkBitcodeWriter(const Module &M, StringTableBuilder &StrtabBuilder,
4699                         BitstreamWriter &Stream,
4700                         const ModuleSummaryIndex &Index,
4701                         const ModuleHash &ModHash)
4702       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
4703                                 /*ShouldPreserveUseListOrder=*/false, &Index),
4704         ModHash(&ModHash) {}
4705 
4706   void write();
4707 
4708 private:
4709   void writeSimplifiedModuleInfo();
4710 };
4711 
4712 } // end anonymous namespace
4713 
4714 // This function writes a simpilified module info for thin link bitcode file.
4715 // It only contains the source file name along with the name(the offset and
4716 // size in strtab) and linkage for global values. For the global value info
4717 // entry, in order to keep linkage at offset 5, there are three zeros used
4718 // as padding.
4719 void ThinLinkBitcodeWriter::writeSimplifiedModuleInfo() {
4720   SmallVector<unsigned, 64> Vals;
4721   // Emit the module's source file name.
4722   {
4723     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
4724     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
4725     if (Bits == SE_Char6)
4726       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
4727     else if (Bits == SE_Fixed7)
4728       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
4729 
4730     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
4731     auto Abbv = std::make_shared<BitCodeAbbrev>();
4732     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
4733     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4734     Abbv->Add(AbbrevOpToUse);
4735     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4736 
4737     for (const auto P : M.getSourceFileName())
4738       Vals.push_back((unsigned char)P);
4739 
4740     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
4741     Vals.clear();
4742   }
4743 
4744   // Emit the global variable information.
4745   for (const GlobalVariable &GV : M.globals()) {
4746     // GLOBALVAR: [strtab offset, strtab size, 0, 0, 0, linkage]
4747     Vals.push_back(StrtabBuilder.add(GV.getName()));
4748     Vals.push_back(GV.getName().size());
4749     Vals.push_back(0);
4750     Vals.push_back(0);
4751     Vals.push_back(0);
4752     Vals.push_back(getEncodedLinkage(GV));
4753 
4754     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals);
4755     Vals.clear();
4756   }
4757 
4758   // Emit the function proto information.
4759   for (const Function &F : M) {
4760     // FUNCTION:  [strtab offset, strtab size, 0, 0, 0, linkage]
4761     Vals.push_back(StrtabBuilder.add(F.getName()));
4762     Vals.push_back(F.getName().size());
4763     Vals.push_back(0);
4764     Vals.push_back(0);
4765     Vals.push_back(0);
4766     Vals.push_back(getEncodedLinkage(F));
4767 
4768     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals);
4769     Vals.clear();
4770   }
4771 
4772   // Emit the alias information.
4773   for (const GlobalAlias &A : M.aliases()) {
4774     // ALIAS: [strtab offset, strtab size, 0, 0, 0, linkage]
4775     Vals.push_back(StrtabBuilder.add(A.getName()));
4776     Vals.push_back(A.getName().size());
4777     Vals.push_back(0);
4778     Vals.push_back(0);
4779     Vals.push_back(0);
4780     Vals.push_back(getEncodedLinkage(A));
4781 
4782     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals);
4783     Vals.clear();
4784   }
4785 
4786   // Emit the ifunc information.
4787   for (const GlobalIFunc &I : M.ifuncs()) {
4788     // IFUNC: [strtab offset, strtab size, 0, 0, 0, linkage]
4789     Vals.push_back(StrtabBuilder.add(I.getName()));
4790     Vals.push_back(I.getName().size());
4791     Vals.push_back(0);
4792     Vals.push_back(0);
4793     Vals.push_back(0);
4794     Vals.push_back(getEncodedLinkage(I));
4795 
4796     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
4797     Vals.clear();
4798   }
4799 }
4800 
4801 void ThinLinkBitcodeWriter::write() {
4802   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4803 
4804   writeModuleVersion();
4805 
4806   writeSimplifiedModuleInfo();
4807 
4808   writePerModuleGlobalValueSummary();
4809 
4810   // Write module hash.
4811   Stream.EmitRecord(bitc::MODULE_CODE_HASH, ArrayRef<uint32_t>(*ModHash));
4812 
4813   Stream.ExitBlock();
4814 }
4815 
4816 void BitcodeWriter::writeThinLinkBitcode(const Module &M,
4817                                          const ModuleSummaryIndex &Index,
4818                                          const ModuleHash &ModHash) {
4819   assert(!WroteStrtab);
4820 
4821   // The Mods vector is used by irsymtab::build, which requires non-const
4822   // Modules in case it needs to materialize metadata. But the bitcode writer
4823   // requires that the module is materialized, so we can cast to non-const here,
4824   // after checking that it is in fact materialized.
4825   assert(M.isMaterialized());
4826   Mods.push_back(const_cast<Module *>(&M));
4827 
4828   ThinLinkBitcodeWriter ThinLinkWriter(M, StrtabBuilder, *Stream, Index,
4829                                        ModHash);
4830   ThinLinkWriter.write();
4831 }
4832 
4833 // Write the specified thin link bitcode file to the given raw output stream,
4834 // where it will be written in a new bitcode block. This is used when
4835 // writing the per-module index file for ThinLTO.
4836 void llvm::writeThinLinkBitcodeToFile(const Module &M, raw_ostream &Out,
4837                                       const ModuleSummaryIndex &Index,
4838                                       const ModuleHash &ModHash) {
4839   SmallVector<char, 0> Buffer;
4840   Buffer.reserve(256 * 1024);
4841 
4842   BitcodeWriter Writer(Buffer);
4843   Writer.writeThinLinkBitcode(M, Index, ModHash);
4844   Writer.writeSymtab();
4845   Writer.writeStrtab();
4846 
4847   Out.write((char *)&Buffer.front(), Buffer.size());
4848 }
4849 
4850 static const char *getSectionNameForBitcode(const Triple &T) {
4851   switch (T.getObjectFormat()) {
4852   case Triple::MachO:
4853     return "__LLVM,__bitcode";
4854   case Triple::COFF:
4855   case Triple::ELF:
4856   case Triple::Wasm:
4857   case Triple::UnknownObjectFormat:
4858     return ".llvmbc";
4859   case Triple::GOFF:
4860     llvm_unreachable("GOFF is not yet implemented");
4861     break;
4862   case Triple::XCOFF:
4863     llvm_unreachable("XCOFF is not yet implemented");
4864     break;
4865   }
4866   llvm_unreachable("Unimplemented ObjectFormatType");
4867 }
4868 
4869 static const char *getSectionNameForCommandline(const Triple &T) {
4870   switch (T.getObjectFormat()) {
4871   case Triple::MachO:
4872     return "__LLVM,__cmdline";
4873   case Triple::COFF:
4874   case Triple::ELF:
4875   case Triple::Wasm:
4876   case Triple::UnknownObjectFormat:
4877     return ".llvmcmd";
4878   case Triple::GOFF:
4879     llvm_unreachable("GOFF is not yet implemented");
4880     break;
4881   case Triple::XCOFF:
4882     llvm_unreachable("XCOFF is not yet implemented");
4883     break;
4884   }
4885   llvm_unreachable("Unimplemented ObjectFormatType");
4886 }
4887 
4888 void llvm::embedBitcodeInModule(llvm::Module &M, llvm::MemoryBufferRef Buf,
4889                                 bool EmbedBitcode, bool EmbedCmdline,
4890                                 const std::vector<uint8_t> &CmdArgs) {
4891   // Save llvm.compiler.used and remove it.
4892   SmallVector<Constant *, 2> UsedArray;
4893   SmallVector<GlobalValue *, 4> UsedGlobals;
4894   Type *UsedElementType = Type::getInt8Ty(M.getContext())->getPointerTo(0);
4895   GlobalVariable *Used = collectUsedGlobalVariables(M, UsedGlobals, true);
4896   for (auto *GV : UsedGlobals) {
4897     if (GV->getName() != "llvm.embedded.module" &&
4898         GV->getName() != "llvm.cmdline")
4899       UsedArray.push_back(
4900           ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
4901   }
4902   if (Used)
4903     Used->eraseFromParent();
4904 
4905   // Embed the bitcode for the llvm module.
4906   std::string Data;
4907   ArrayRef<uint8_t> ModuleData;
4908   Triple T(M.getTargetTriple());
4909 
4910   if (EmbedBitcode) {
4911     if (Buf.getBufferSize() == 0 ||
4912         !isBitcode((const unsigned char *)Buf.getBufferStart(),
4913                    (const unsigned char *)Buf.getBufferEnd())) {
4914       // If the input is LLVM Assembly, bitcode is produced by serializing
4915       // the module. Use-lists order need to be preserved in this case.
4916       llvm::raw_string_ostream OS(Data);
4917       llvm::WriteBitcodeToFile(M, OS, /* ShouldPreserveUseListOrder */ true);
4918       ModuleData =
4919           ArrayRef<uint8_t>((const uint8_t *)OS.str().data(), OS.str().size());
4920     } else
4921       // If the input is LLVM bitcode, write the input byte stream directly.
4922       ModuleData = ArrayRef<uint8_t>((const uint8_t *)Buf.getBufferStart(),
4923                                      Buf.getBufferSize());
4924   }
4925   llvm::Constant *ModuleConstant =
4926       llvm::ConstantDataArray::get(M.getContext(), ModuleData);
4927   llvm::GlobalVariable *GV = new llvm::GlobalVariable(
4928       M, ModuleConstant->getType(), true, llvm::GlobalValue::PrivateLinkage,
4929       ModuleConstant);
4930   GV->setSection(getSectionNameForBitcode(T));
4931   // Set alignment to 1 to prevent padding between two contributions from input
4932   // sections after linking.
4933   GV->setAlignment(Align(1));
4934   UsedArray.push_back(
4935       ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
4936   if (llvm::GlobalVariable *Old =
4937           M.getGlobalVariable("llvm.embedded.module", true)) {
4938     assert(Old->hasOneUse() &&
4939            "llvm.embedded.module can only be used once in llvm.compiler.used");
4940     GV->takeName(Old);
4941     Old->eraseFromParent();
4942   } else {
4943     GV->setName("llvm.embedded.module");
4944   }
4945 
4946   // Skip if only bitcode needs to be embedded.
4947   if (EmbedCmdline) {
4948     // Embed command-line options.
4949     ArrayRef<uint8_t> CmdData(const_cast<uint8_t *>(CmdArgs.data()),
4950                               CmdArgs.size());
4951     llvm::Constant *CmdConstant =
4952         llvm::ConstantDataArray::get(M.getContext(), CmdData);
4953     GV = new llvm::GlobalVariable(M, CmdConstant->getType(), true,
4954                                   llvm::GlobalValue::PrivateLinkage,
4955                                   CmdConstant);
4956     GV->setSection(getSectionNameForCommandline(T));
4957     GV->setAlignment(Align(1));
4958     UsedArray.push_back(
4959         ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
4960     if (llvm::GlobalVariable *Old = M.getGlobalVariable("llvm.cmdline", true)) {
4961       assert(Old->hasOneUse() &&
4962              "llvm.cmdline can only be used once in llvm.compiler.used");
4963       GV->takeName(Old);
4964       Old->eraseFromParent();
4965     } else {
4966       GV->setName("llvm.cmdline");
4967     }
4968   }
4969 
4970   if (UsedArray.empty())
4971     return;
4972 
4973   // Recreate llvm.compiler.used.
4974   ArrayType *ATy = ArrayType::get(UsedElementType, UsedArray.size());
4975   auto *NewUsed = new GlobalVariable(
4976       M, ATy, false, llvm::GlobalValue::AppendingLinkage,
4977       llvm::ConstantArray::get(ATy, UsedArray), "llvm.compiler.used");
4978   NewUsed->setSection("llvm.metadata");
4979 }
4980