xref: /llvm-project/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp (revision 42861faa8e17058f0b4a027bba13ef59a600e051)
1 //===- Bitcode/Writer/BitcodeWriter.cpp - Bitcode Writer ------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // Bitcode writer implementation.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "llvm/Bitcode/BitcodeWriter.h"
14 #include "ValueEnumerator.h"
15 #include "llvm/ADT/APFloat.h"
16 #include "llvm/ADT/APInt.h"
17 #include "llvm/ADT/ArrayRef.h"
18 #include "llvm/ADT/DenseMap.h"
19 #include "llvm/ADT/None.h"
20 #include "llvm/ADT/Optional.h"
21 #include "llvm/ADT/STLExtras.h"
22 #include "llvm/ADT/SetVector.h"
23 #include "llvm/ADT/SmallPtrSet.h"
24 #include "llvm/ADT/SmallString.h"
25 #include "llvm/ADT/SmallVector.h"
26 #include "llvm/ADT/StringMap.h"
27 #include "llvm/ADT/StringRef.h"
28 #include "llvm/ADT/Triple.h"
29 #include "llvm/Bitcode/BitcodeCommon.h"
30 #include "llvm/Bitcode/BitcodeReader.h"
31 #include "llvm/Bitcode/LLVMBitCodes.h"
32 #include "llvm/Bitstream/BitCodes.h"
33 #include "llvm/Bitstream/BitstreamWriter.h"
34 #include "llvm/Config/llvm-config.h"
35 #include "llvm/IR/Attributes.h"
36 #include "llvm/IR/BasicBlock.h"
37 #include "llvm/IR/Comdat.h"
38 #include "llvm/IR/Constant.h"
39 #include "llvm/IR/Constants.h"
40 #include "llvm/IR/DebugInfoMetadata.h"
41 #include "llvm/IR/DebugLoc.h"
42 #include "llvm/IR/DerivedTypes.h"
43 #include "llvm/IR/Function.h"
44 #include "llvm/IR/GlobalAlias.h"
45 #include "llvm/IR/GlobalIFunc.h"
46 #include "llvm/IR/GlobalObject.h"
47 #include "llvm/IR/GlobalValue.h"
48 #include "llvm/IR/GlobalVariable.h"
49 #include "llvm/IR/InlineAsm.h"
50 #include "llvm/IR/InstrTypes.h"
51 #include "llvm/IR/Instruction.h"
52 #include "llvm/IR/Instructions.h"
53 #include "llvm/IR/LLVMContext.h"
54 #include "llvm/IR/Metadata.h"
55 #include "llvm/IR/Module.h"
56 #include "llvm/IR/ModuleSummaryIndex.h"
57 #include "llvm/IR/Operator.h"
58 #include "llvm/IR/Type.h"
59 #include "llvm/IR/UseListOrder.h"
60 #include "llvm/IR/Value.h"
61 #include "llvm/IR/ValueSymbolTable.h"
62 #include "llvm/MC/StringTableBuilder.h"
63 #include "llvm/MC/TargetRegistry.h"
64 #include "llvm/Object/IRSymtab.h"
65 #include "llvm/Support/AtomicOrdering.h"
66 #include "llvm/Support/Casting.h"
67 #include "llvm/Support/CommandLine.h"
68 #include "llvm/Support/Endian.h"
69 #include "llvm/Support/Error.h"
70 #include "llvm/Support/ErrorHandling.h"
71 #include "llvm/Support/MathExtras.h"
72 #include "llvm/Support/SHA1.h"
73 #include "llvm/Support/raw_ostream.h"
74 #include <algorithm>
75 #include <cassert>
76 #include <cstddef>
77 #include <cstdint>
78 #include <iterator>
79 #include <map>
80 #include <memory>
81 #include <string>
82 #include <utility>
83 #include <vector>
84 
85 using namespace llvm;
86 
87 static cl::opt<unsigned>
88     IndexThreshold("bitcode-mdindex-threshold", cl::Hidden, cl::init(25),
89                    cl::desc("Number of metadatas above which we emit an index "
90                             "to enable lazy-loading"));
91 static cl::opt<uint32_t> FlushThreshold(
92     "bitcode-flush-threshold", cl::Hidden, cl::init(512),
93     cl::desc("The threshold (unit M) for flushing LLVM bitcode."));
94 
95 static cl::opt<bool> WriteRelBFToSummary(
96     "write-relbf-to-summary", cl::Hidden, cl::init(false),
97     cl::desc("Write relative block frequency to function summary "));
98 
99 extern FunctionSummary::ForceSummaryHotnessType ForceSummaryEdgesCold;
100 
101 namespace {
102 
103 /// These are manifest constants used by the bitcode writer. They do not need to
104 /// be kept in sync with the reader, but need to be consistent within this file.
105 enum {
106   // VALUE_SYMTAB_BLOCK abbrev id's.
107   VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
108   VST_ENTRY_7_ABBREV,
109   VST_ENTRY_6_ABBREV,
110   VST_BBENTRY_6_ABBREV,
111 
112   // CONSTANTS_BLOCK abbrev id's.
113   CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
114   CONSTANTS_INTEGER_ABBREV,
115   CONSTANTS_CE_CAST_Abbrev,
116   CONSTANTS_NULL_Abbrev,
117 
118   // FUNCTION_BLOCK abbrev id's.
119   FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
120   FUNCTION_INST_UNOP_ABBREV,
121   FUNCTION_INST_UNOP_FLAGS_ABBREV,
122   FUNCTION_INST_BINOP_ABBREV,
123   FUNCTION_INST_BINOP_FLAGS_ABBREV,
124   FUNCTION_INST_CAST_ABBREV,
125   FUNCTION_INST_RET_VOID_ABBREV,
126   FUNCTION_INST_RET_VAL_ABBREV,
127   FUNCTION_INST_UNREACHABLE_ABBREV,
128   FUNCTION_INST_GEP_ABBREV,
129 };
130 
131 /// Abstract class to manage the bitcode writing, subclassed for each bitcode
132 /// file type.
133 class BitcodeWriterBase {
134 protected:
135   /// The stream created and owned by the client.
136   BitstreamWriter &Stream;
137 
138   StringTableBuilder &StrtabBuilder;
139 
140 public:
141   /// Constructs a BitcodeWriterBase object that writes to the provided
142   /// \p Stream.
143   BitcodeWriterBase(BitstreamWriter &Stream, StringTableBuilder &StrtabBuilder)
144       : Stream(Stream), StrtabBuilder(StrtabBuilder) {}
145 
146 protected:
147   void writeModuleVersion();
148 };
149 
150 void BitcodeWriterBase::writeModuleVersion() {
151   // VERSION: [version#]
152   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, ArrayRef<uint64_t>{2});
153 }
154 
155 /// Base class to manage the module bitcode writing, currently subclassed for
156 /// ModuleBitcodeWriter and ThinLinkBitcodeWriter.
157 class ModuleBitcodeWriterBase : public BitcodeWriterBase {
158 protected:
159   /// The Module to write to bitcode.
160   const Module &M;
161 
162   /// Enumerates ids for all values in the module.
163   ValueEnumerator VE;
164 
165   /// Optional per-module index to write for ThinLTO.
166   const ModuleSummaryIndex *Index;
167 
168   /// Map that holds the correspondence between GUIDs in the summary index,
169   /// that came from indirect call profiles, and a value id generated by this
170   /// class to use in the VST and summary block records.
171   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
172 
173   /// Tracks the last value id recorded in the GUIDToValueMap.
174   unsigned GlobalValueId;
175 
176   /// Saves the offset of the VSTOffset record that must eventually be
177   /// backpatched with the offset of the actual VST.
178   uint64_t VSTOffsetPlaceholder = 0;
179 
180 public:
181   /// Constructs a ModuleBitcodeWriterBase object for the given Module,
182   /// writing to the provided \p Buffer.
183   ModuleBitcodeWriterBase(const Module &M, StringTableBuilder &StrtabBuilder,
184                           BitstreamWriter &Stream,
185                           bool ShouldPreserveUseListOrder,
186                           const ModuleSummaryIndex *Index)
187       : BitcodeWriterBase(Stream, StrtabBuilder), M(M),
188         VE(M, ShouldPreserveUseListOrder), Index(Index) {
189     // Assign ValueIds to any callee values in the index that came from
190     // indirect call profiles and were recorded as a GUID not a Value*
191     // (which would have been assigned an ID by the ValueEnumerator).
192     // The starting ValueId is just after the number of values in the
193     // ValueEnumerator, so that they can be emitted in the VST.
194     GlobalValueId = VE.getValues().size();
195     if (!Index)
196       return;
197     for (const auto &GUIDSummaryLists : *Index)
198       // Examine all summaries for this GUID.
199       for (auto &Summary : GUIDSummaryLists.second.SummaryList)
200         if (auto FS = dyn_cast<FunctionSummary>(Summary.get()))
201           // For each call in the function summary, see if the call
202           // is to a GUID (which means it is for an indirect call,
203           // otherwise we would have a Value for it). If so, synthesize
204           // a value id.
205           for (auto &CallEdge : FS->calls())
206             if (!CallEdge.first.haveGVs() || !CallEdge.first.getValue())
207               assignValueId(CallEdge.first.getGUID());
208   }
209 
210 protected:
211   void writePerModuleGlobalValueSummary();
212 
213 private:
214   void writePerModuleFunctionSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
215                                            GlobalValueSummary *Summary,
216                                            unsigned ValueID,
217                                            unsigned FSCallsAbbrev,
218                                            unsigned FSCallsProfileAbbrev,
219                                            const Function &F);
220   void writeModuleLevelReferences(const GlobalVariable &V,
221                                   SmallVector<uint64_t, 64> &NameVals,
222                                   unsigned FSModRefsAbbrev,
223                                   unsigned FSModVTableRefsAbbrev);
224 
225   void assignValueId(GlobalValue::GUID ValGUID) {
226     GUIDToValueIdMap[ValGUID] = ++GlobalValueId;
227   }
228 
229   unsigned getValueId(GlobalValue::GUID ValGUID) {
230     const auto &VMI = GUIDToValueIdMap.find(ValGUID);
231     // Expect that any GUID value had a value Id assigned by an
232     // earlier call to assignValueId.
233     assert(VMI != GUIDToValueIdMap.end() &&
234            "GUID does not have assigned value Id");
235     return VMI->second;
236   }
237 
238   // Helper to get the valueId for the type of value recorded in VI.
239   unsigned getValueId(ValueInfo VI) {
240     if (!VI.haveGVs() || !VI.getValue())
241       return getValueId(VI.getGUID());
242     return VE.getValueID(VI.getValue());
243   }
244 
245   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
246 };
247 
248 /// Class to manage the bitcode writing for a module.
249 class ModuleBitcodeWriter : public ModuleBitcodeWriterBase {
250   /// Pointer to the buffer allocated by caller for bitcode writing.
251   const SmallVectorImpl<char> &Buffer;
252 
253   /// True if a module hash record should be written.
254   bool GenerateHash;
255 
256   /// If non-null, when GenerateHash is true, the resulting hash is written
257   /// into ModHash.
258   ModuleHash *ModHash;
259 
260   SHA1 Hasher;
261 
262   /// The start bit of the identification block.
263   uint64_t BitcodeStartBit;
264 
265 public:
266   /// Constructs a ModuleBitcodeWriter object for the given Module,
267   /// writing to the provided \p Buffer.
268   ModuleBitcodeWriter(const Module &M, SmallVectorImpl<char> &Buffer,
269                       StringTableBuilder &StrtabBuilder,
270                       BitstreamWriter &Stream, bool ShouldPreserveUseListOrder,
271                       const ModuleSummaryIndex *Index, bool GenerateHash,
272                       ModuleHash *ModHash = nullptr)
273       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
274                                 ShouldPreserveUseListOrder, Index),
275         Buffer(Buffer), GenerateHash(GenerateHash), ModHash(ModHash),
276         BitcodeStartBit(Stream.GetCurrentBitNo()) {}
277 
278   /// Emit the current module to the bitstream.
279   void write();
280 
281 private:
282   uint64_t bitcodeStartBit() { return BitcodeStartBit; }
283 
284   size_t addToStrtab(StringRef Str);
285 
286   void writeAttributeGroupTable();
287   void writeAttributeTable();
288   void writeTypeTable();
289   void writeComdats();
290   void writeValueSymbolTableForwardDecl();
291   void writeModuleInfo();
292   void writeValueAsMetadata(const ValueAsMetadata *MD,
293                             SmallVectorImpl<uint64_t> &Record);
294   void writeMDTuple(const MDTuple *N, SmallVectorImpl<uint64_t> &Record,
295                     unsigned Abbrev);
296   unsigned createDILocationAbbrev();
297   void writeDILocation(const DILocation *N, SmallVectorImpl<uint64_t> &Record,
298                        unsigned &Abbrev);
299   unsigned createGenericDINodeAbbrev();
300   void writeGenericDINode(const GenericDINode *N,
301                           SmallVectorImpl<uint64_t> &Record, unsigned &Abbrev);
302   void writeDISubrange(const DISubrange *N, SmallVectorImpl<uint64_t> &Record,
303                        unsigned Abbrev);
304   void writeDIGenericSubrange(const DIGenericSubrange *N,
305                               SmallVectorImpl<uint64_t> &Record,
306                               unsigned Abbrev);
307   void writeDIEnumerator(const DIEnumerator *N,
308                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
309   void writeDIBasicType(const DIBasicType *N, SmallVectorImpl<uint64_t> &Record,
310                         unsigned Abbrev);
311   void writeDIStringType(const DIStringType *N,
312                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
313   void writeDIDerivedType(const DIDerivedType *N,
314                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
315   void writeDICompositeType(const DICompositeType *N,
316                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
317   void writeDISubroutineType(const DISubroutineType *N,
318                              SmallVectorImpl<uint64_t> &Record,
319                              unsigned Abbrev);
320   void writeDIFile(const DIFile *N, SmallVectorImpl<uint64_t> &Record,
321                    unsigned Abbrev);
322   void writeDICompileUnit(const DICompileUnit *N,
323                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
324   void writeDISubprogram(const DISubprogram *N,
325                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
326   void writeDILexicalBlock(const DILexicalBlock *N,
327                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
328   void writeDILexicalBlockFile(const DILexicalBlockFile *N,
329                                SmallVectorImpl<uint64_t> &Record,
330                                unsigned Abbrev);
331   void writeDICommonBlock(const DICommonBlock *N,
332                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
333   void writeDINamespace(const DINamespace *N, SmallVectorImpl<uint64_t> &Record,
334                         unsigned Abbrev);
335   void writeDIMacro(const DIMacro *N, SmallVectorImpl<uint64_t> &Record,
336                     unsigned Abbrev);
337   void writeDIMacroFile(const DIMacroFile *N, SmallVectorImpl<uint64_t> &Record,
338                         unsigned Abbrev);
339   void writeDIArgList(const DIArgList *N, SmallVectorImpl<uint64_t> &Record,
340                       unsigned Abbrev);
341   void writeDIModule(const DIModule *N, SmallVectorImpl<uint64_t> &Record,
342                      unsigned Abbrev);
343   void writeDITemplateTypeParameter(const DITemplateTypeParameter *N,
344                                     SmallVectorImpl<uint64_t> &Record,
345                                     unsigned Abbrev);
346   void writeDITemplateValueParameter(const DITemplateValueParameter *N,
347                                      SmallVectorImpl<uint64_t> &Record,
348                                      unsigned Abbrev);
349   void writeDIGlobalVariable(const DIGlobalVariable *N,
350                              SmallVectorImpl<uint64_t> &Record,
351                              unsigned Abbrev);
352   void writeDILocalVariable(const DILocalVariable *N,
353                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
354   void writeDILabel(const DILabel *N,
355                     SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
356   void writeDIExpression(const DIExpression *N,
357                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
358   void writeDIGlobalVariableExpression(const DIGlobalVariableExpression *N,
359                                        SmallVectorImpl<uint64_t> &Record,
360                                        unsigned Abbrev);
361   void writeDIObjCProperty(const DIObjCProperty *N,
362                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
363   void writeDIImportedEntity(const DIImportedEntity *N,
364                              SmallVectorImpl<uint64_t> &Record,
365                              unsigned Abbrev);
366   unsigned createNamedMetadataAbbrev();
367   void writeNamedMetadata(SmallVectorImpl<uint64_t> &Record);
368   unsigned createMetadataStringsAbbrev();
369   void writeMetadataStrings(ArrayRef<const Metadata *> Strings,
370                             SmallVectorImpl<uint64_t> &Record);
371   void writeMetadataRecords(ArrayRef<const Metadata *> MDs,
372                             SmallVectorImpl<uint64_t> &Record,
373                             std::vector<unsigned> *MDAbbrevs = nullptr,
374                             std::vector<uint64_t> *IndexPos = nullptr);
375   void writeModuleMetadata();
376   void writeFunctionMetadata(const Function &F);
377   void writeFunctionMetadataAttachment(const Function &F);
378   void pushGlobalMetadataAttachment(SmallVectorImpl<uint64_t> &Record,
379                                     const GlobalObject &GO);
380   void writeModuleMetadataKinds();
381   void writeOperandBundleTags();
382   void writeSyncScopeNames();
383   void writeConstants(unsigned FirstVal, unsigned LastVal, bool isGlobal);
384   void writeModuleConstants();
385   bool pushValueAndType(const Value *V, unsigned InstID,
386                         SmallVectorImpl<unsigned> &Vals);
387   void writeOperandBundles(const CallBase &CB, unsigned InstID);
388   void pushValue(const Value *V, unsigned InstID,
389                  SmallVectorImpl<unsigned> &Vals);
390   void pushValueSigned(const Value *V, unsigned InstID,
391                        SmallVectorImpl<uint64_t> &Vals);
392   void writeInstruction(const Instruction &I, unsigned InstID,
393                         SmallVectorImpl<unsigned> &Vals);
394   void writeFunctionLevelValueSymbolTable(const ValueSymbolTable &VST);
395   void writeGlobalValueSymbolTable(
396       DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
397   void writeUseList(UseListOrder &&Order);
398   void writeUseListBlock(const Function *F);
399   void
400   writeFunction(const Function &F,
401                 DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
402   void writeBlockInfo();
403   void writeModuleHash(size_t BlockStartPos);
404 
405   unsigned getEncodedSyncScopeID(SyncScope::ID SSID) {
406     return unsigned(SSID);
407   }
408 
409   unsigned getEncodedAlign(MaybeAlign Alignment) { return encode(Alignment); }
410 };
411 
412 /// Class to manage the bitcode writing for a combined index.
413 class IndexBitcodeWriter : public BitcodeWriterBase {
414   /// The combined index to write to bitcode.
415   const ModuleSummaryIndex &Index;
416 
417   /// When writing a subset of the index for distributed backends, client
418   /// provides a map of modules to the corresponding GUIDs/summaries to write.
419   const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex;
420 
421   /// Map that holds the correspondence between the GUID used in the combined
422   /// index and a value id generated by this class to use in references.
423   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
424 
425   /// Tracks the last value id recorded in the GUIDToValueMap.
426   unsigned GlobalValueId = 0;
427 
428 public:
429   /// Constructs a IndexBitcodeWriter object for the given combined index,
430   /// writing to the provided \p Buffer. When writing a subset of the index
431   /// for a distributed backend, provide a \p ModuleToSummariesForIndex map.
432   IndexBitcodeWriter(BitstreamWriter &Stream, StringTableBuilder &StrtabBuilder,
433                      const ModuleSummaryIndex &Index,
434                      const std::map<std::string, GVSummaryMapTy>
435                          *ModuleToSummariesForIndex = nullptr)
436       : BitcodeWriterBase(Stream, StrtabBuilder), Index(Index),
437         ModuleToSummariesForIndex(ModuleToSummariesForIndex) {
438     // Assign unique value ids to all summaries to be written, for use
439     // in writing out the call graph edges. Save the mapping from GUID
440     // to the new global value id to use when writing those edges, which
441     // are currently saved in the index in terms of GUID.
442     forEachSummary([&](GVInfo I, bool) {
443       GUIDToValueIdMap[I.first] = ++GlobalValueId;
444     });
445   }
446 
447   /// The below iterator returns the GUID and associated summary.
448   using GVInfo = std::pair<GlobalValue::GUID, GlobalValueSummary *>;
449 
450   /// Calls the callback for each value GUID and summary to be written to
451   /// bitcode. This hides the details of whether they are being pulled from the
452   /// entire index or just those in a provided ModuleToSummariesForIndex map.
453   template<typename Functor>
454   void forEachSummary(Functor Callback) {
455     if (ModuleToSummariesForIndex) {
456       for (auto &M : *ModuleToSummariesForIndex)
457         for (auto &Summary : M.second) {
458           Callback(Summary, false);
459           // Ensure aliasee is handled, e.g. for assigning a valueId,
460           // even if we are not importing the aliasee directly (the
461           // imported alias will contain a copy of aliasee).
462           if (auto *AS = dyn_cast<AliasSummary>(Summary.getSecond()))
463             Callback({AS->getAliaseeGUID(), &AS->getAliasee()}, true);
464         }
465     } else {
466       for (auto &Summaries : Index)
467         for (auto &Summary : Summaries.second.SummaryList)
468           Callback({Summaries.first, Summary.get()}, false);
469     }
470   }
471 
472   /// Calls the callback for each entry in the modulePaths StringMap that
473   /// should be written to the module path string table. This hides the details
474   /// of whether they are being pulled from the entire index or just those in a
475   /// provided ModuleToSummariesForIndex map.
476   template <typename Functor> void forEachModule(Functor Callback) {
477     if (ModuleToSummariesForIndex) {
478       for (const auto &M : *ModuleToSummariesForIndex) {
479         const auto &MPI = Index.modulePaths().find(M.first);
480         if (MPI == Index.modulePaths().end()) {
481           // This should only happen if the bitcode file was empty, in which
482           // case we shouldn't be importing (the ModuleToSummariesForIndex
483           // would only include the module we are writing and index for).
484           assert(ModuleToSummariesForIndex->size() == 1);
485           continue;
486         }
487         Callback(*MPI);
488       }
489     } else {
490       for (const auto &MPSE : Index.modulePaths())
491         Callback(MPSE);
492     }
493   }
494 
495   /// Main entry point for writing a combined index to bitcode.
496   void write();
497 
498 private:
499   void writeModStrings();
500   void writeCombinedGlobalValueSummary();
501 
502   Optional<unsigned> getValueId(GlobalValue::GUID ValGUID) {
503     auto VMI = GUIDToValueIdMap.find(ValGUID);
504     if (VMI == GUIDToValueIdMap.end())
505       return None;
506     return VMI->second;
507   }
508 
509   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
510 };
511 
512 } // end anonymous namespace
513 
514 static unsigned getEncodedCastOpcode(unsigned Opcode) {
515   switch (Opcode) {
516   default: llvm_unreachable("Unknown cast instruction!");
517   case Instruction::Trunc   : return bitc::CAST_TRUNC;
518   case Instruction::ZExt    : return bitc::CAST_ZEXT;
519   case Instruction::SExt    : return bitc::CAST_SEXT;
520   case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
521   case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
522   case Instruction::UIToFP  : return bitc::CAST_UITOFP;
523   case Instruction::SIToFP  : return bitc::CAST_SITOFP;
524   case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
525   case Instruction::FPExt   : return bitc::CAST_FPEXT;
526   case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
527   case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
528   case Instruction::BitCast : return bitc::CAST_BITCAST;
529   case Instruction::AddrSpaceCast: return bitc::CAST_ADDRSPACECAST;
530   }
531 }
532 
533 static unsigned getEncodedUnaryOpcode(unsigned Opcode) {
534   switch (Opcode) {
535   default: llvm_unreachable("Unknown binary instruction!");
536   case Instruction::FNeg: return bitc::UNOP_FNEG;
537   }
538 }
539 
540 static unsigned getEncodedBinaryOpcode(unsigned Opcode) {
541   switch (Opcode) {
542   default: llvm_unreachable("Unknown binary instruction!");
543   case Instruction::Add:
544   case Instruction::FAdd: return bitc::BINOP_ADD;
545   case Instruction::Sub:
546   case Instruction::FSub: return bitc::BINOP_SUB;
547   case Instruction::Mul:
548   case Instruction::FMul: return bitc::BINOP_MUL;
549   case Instruction::UDiv: return bitc::BINOP_UDIV;
550   case Instruction::FDiv:
551   case Instruction::SDiv: return bitc::BINOP_SDIV;
552   case Instruction::URem: return bitc::BINOP_UREM;
553   case Instruction::FRem:
554   case Instruction::SRem: return bitc::BINOP_SREM;
555   case Instruction::Shl:  return bitc::BINOP_SHL;
556   case Instruction::LShr: return bitc::BINOP_LSHR;
557   case Instruction::AShr: return bitc::BINOP_ASHR;
558   case Instruction::And:  return bitc::BINOP_AND;
559   case Instruction::Or:   return bitc::BINOP_OR;
560   case Instruction::Xor:  return bitc::BINOP_XOR;
561   }
562 }
563 
564 static unsigned getEncodedRMWOperation(AtomicRMWInst::BinOp Op) {
565   switch (Op) {
566   default: llvm_unreachable("Unknown RMW operation!");
567   case AtomicRMWInst::Xchg: return bitc::RMW_XCHG;
568   case AtomicRMWInst::Add: return bitc::RMW_ADD;
569   case AtomicRMWInst::Sub: return bitc::RMW_SUB;
570   case AtomicRMWInst::And: return bitc::RMW_AND;
571   case AtomicRMWInst::Nand: return bitc::RMW_NAND;
572   case AtomicRMWInst::Or: return bitc::RMW_OR;
573   case AtomicRMWInst::Xor: return bitc::RMW_XOR;
574   case AtomicRMWInst::Max: return bitc::RMW_MAX;
575   case AtomicRMWInst::Min: return bitc::RMW_MIN;
576   case AtomicRMWInst::UMax: return bitc::RMW_UMAX;
577   case AtomicRMWInst::UMin: return bitc::RMW_UMIN;
578   case AtomicRMWInst::FAdd: return bitc::RMW_FADD;
579   case AtomicRMWInst::FSub: return bitc::RMW_FSUB;
580   }
581 }
582 
583 static unsigned getEncodedOrdering(AtomicOrdering Ordering) {
584   switch (Ordering) {
585   case AtomicOrdering::NotAtomic: return bitc::ORDERING_NOTATOMIC;
586   case AtomicOrdering::Unordered: return bitc::ORDERING_UNORDERED;
587   case AtomicOrdering::Monotonic: return bitc::ORDERING_MONOTONIC;
588   case AtomicOrdering::Acquire: return bitc::ORDERING_ACQUIRE;
589   case AtomicOrdering::Release: return bitc::ORDERING_RELEASE;
590   case AtomicOrdering::AcquireRelease: return bitc::ORDERING_ACQREL;
591   case AtomicOrdering::SequentiallyConsistent: return bitc::ORDERING_SEQCST;
592   }
593   llvm_unreachable("Invalid ordering");
594 }
595 
596 static void writeStringRecord(BitstreamWriter &Stream, unsigned Code,
597                               StringRef Str, unsigned AbbrevToUse) {
598   SmallVector<unsigned, 64> Vals;
599 
600   // Code: [strchar x N]
601   for (char C : Str) {
602     if (AbbrevToUse && !BitCodeAbbrevOp::isChar6(C))
603       AbbrevToUse = 0;
604     Vals.push_back(C);
605   }
606 
607   // Emit the finished record.
608   Stream.EmitRecord(Code, Vals, AbbrevToUse);
609 }
610 
611 static uint64_t getAttrKindEncoding(Attribute::AttrKind Kind) {
612   switch (Kind) {
613   case Attribute::Alignment:
614     return bitc::ATTR_KIND_ALIGNMENT;
615   case Attribute::AllocAlign:
616     return bitc::ATTR_KIND_ALLOC_ALIGN;
617   case Attribute::AllocSize:
618     return bitc::ATTR_KIND_ALLOC_SIZE;
619   case Attribute::AlwaysInline:
620     return bitc::ATTR_KIND_ALWAYS_INLINE;
621   case Attribute::ArgMemOnly:
622     return bitc::ATTR_KIND_ARGMEMONLY;
623   case Attribute::Builtin:
624     return bitc::ATTR_KIND_BUILTIN;
625   case Attribute::ByVal:
626     return bitc::ATTR_KIND_BY_VAL;
627   case Attribute::Convergent:
628     return bitc::ATTR_KIND_CONVERGENT;
629   case Attribute::InAlloca:
630     return bitc::ATTR_KIND_IN_ALLOCA;
631   case Attribute::Cold:
632     return bitc::ATTR_KIND_COLD;
633   case Attribute::DisableSanitizerInstrumentation:
634     return bitc::ATTR_KIND_DISABLE_SANITIZER_INSTRUMENTATION;
635   case Attribute::Hot:
636     return bitc::ATTR_KIND_HOT;
637   case Attribute::ElementType:
638     return bitc::ATTR_KIND_ELEMENTTYPE;
639   case Attribute::InaccessibleMemOnly:
640     return bitc::ATTR_KIND_INACCESSIBLEMEM_ONLY;
641   case Attribute::InaccessibleMemOrArgMemOnly:
642     return bitc::ATTR_KIND_INACCESSIBLEMEM_OR_ARGMEMONLY;
643   case Attribute::InlineHint:
644     return bitc::ATTR_KIND_INLINE_HINT;
645   case Attribute::InReg:
646     return bitc::ATTR_KIND_IN_REG;
647   case Attribute::JumpTable:
648     return bitc::ATTR_KIND_JUMP_TABLE;
649   case Attribute::MinSize:
650     return bitc::ATTR_KIND_MIN_SIZE;
651   case Attribute::AllocatedPointer:
652     return bitc::ATTR_KIND_ALLOCATED_POINTER;
653   case Attribute::AllocKind:
654     return bitc::ATTR_KIND_ALLOC_KIND;
655   case Attribute::Naked:
656     return bitc::ATTR_KIND_NAKED;
657   case Attribute::Nest:
658     return bitc::ATTR_KIND_NEST;
659   case Attribute::NoAlias:
660     return bitc::ATTR_KIND_NO_ALIAS;
661   case Attribute::NoBuiltin:
662     return bitc::ATTR_KIND_NO_BUILTIN;
663   case Attribute::NoCallback:
664     return bitc::ATTR_KIND_NO_CALLBACK;
665   case Attribute::NoCapture:
666     return bitc::ATTR_KIND_NO_CAPTURE;
667   case Attribute::NoDuplicate:
668     return bitc::ATTR_KIND_NO_DUPLICATE;
669   case Attribute::NoFree:
670     return bitc::ATTR_KIND_NOFREE;
671   case Attribute::NoImplicitFloat:
672     return bitc::ATTR_KIND_NO_IMPLICIT_FLOAT;
673   case Attribute::NoInline:
674     return bitc::ATTR_KIND_NO_INLINE;
675   case Attribute::NoRecurse:
676     return bitc::ATTR_KIND_NO_RECURSE;
677   case Attribute::NoMerge:
678     return bitc::ATTR_KIND_NO_MERGE;
679   case Attribute::NonLazyBind:
680     return bitc::ATTR_KIND_NON_LAZY_BIND;
681   case Attribute::NonNull:
682     return bitc::ATTR_KIND_NON_NULL;
683   case Attribute::Dereferenceable:
684     return bitc::ATTR_KIND_DEREFERENCEABLE;
685   case Attribute::DereferenceableOrNull:
686     return bitc::ATTR_KIND_DEREFERENCEABLE_OR_NULL;
687   case Attribute::NoRedZone:
688     return bitc::ATTR_KIND_NO_RED_ZONE;
689   case Attribute::NoReturn:
690     return bitc::ATTR_KIND_NO_RETURN;
691   case Attribute::NoSync:
692     return bitc::ATTR_KIND_NOSYNC;
693   case Attribute::NoCfCheck:
694     return bitc::ATTR_KIND_NOCF_CHECK;
695   case Attribute::NoProfile:
696     return bitc::ATTR_KIND_NO_PROFILE;
697   case Attribute::NoUnwind:
698     return bitc::ATTR_KIND_NO_UNWIND;
699   case Attribute::NoSanitizeBounds:
700     return bitc::ATTR_KIND_NO_SANITIZE_BOUNDS;
701   case Attribute::NoSanitizeCoverage:
702     return bitc::ATTR_KIND_NO_SANITIZE_COVERAGE;
703   case Attribute::NullPointerIsValid:
704     return bitc::ATTR_KIND_NULL_POINTER_IS_VALID;
705   case Attribute::OptForFuzzing:
706     return bitc::ATTR_KIND_OPT_FOR_FUZZING;
707   case Attribute::OptimizeForSize:
708     return bitc::ATTR_KIND_OPTIMIZE_FOR_SIZE;
709   case Attribute::OptimizeNone:
710     return bitc::ATTR_KIND_OPTIMIZE_NONE;
711   case Attribute::ReadNone:
712     return bitc::ATTR_KIND_READ_NONE;
713   case Attribute::ReadOnly:
714     return bitc::ATTR_KIND_READ_ONLY;
715   case Attribute::Returned:
716     return bitc::ATTR_KIND_RETURNED;
717   case Attribute::ReturnsTwice:
718     return bitc::ATTR_KIND_RETURNS_TWICE;
719   case Attribute::SExt:
720     return bitc::ATTR_KIND_S_EXT;
721   case Attribute::Speculatable:
722     return bitc::ATTR_KIND_SPECULATABLE;
723   case Attribute::StackAlignment:
724     return bitc::ATTR_KIND_STACK_ALIGNMENT;
725   case Attribute::StackProtect:
726     return bitc::ATTR_KIND_STACK_PROTECT;
727   case Attribute::StackProtectReq:
728     return bitc::ATTR_KIND_STACK_PROTECT_REQ;
729   case Attribute::StackProtectStrong:
730     return bitc::ATTR_KIND_STACK_PROTECT_STRONG;
731   case Attribute::SafeStack:
732     return bitc::ATTR_KIND_SAFESTACK;
733   case Attribute::ShadowCallStack:
734     return bitc::ATTR_KIND_SHADOWCALLSTACK;
735   case Attribute::StrictFP:
736     return bitc::ATTR_KIND_STRICT_FP;
737   case Attribute::StructRet:
738     return bitc::ATTR_KIND_STRUCT_RET;
739   case Attribute::SanitizeAddress:
740     return bitc::ATTR_KIND_SANITIZE_ADDRESS;
741   case Attribute::SanitizeHWAddress:
742     return bitc::ATTR_KIND_SANITIZE_HWADDRESS;
743   case Attribute::SanitizeThread:
744     return bitc::ATTR_KIND_SANITIZE_THREAD;
745   case Attribute::SanitizeMemory:
746     return bitc::ATTR_KIND_SANITIZE_MEMORY;
747   case Attribute::SpeculativeLoadHardening:
748     return bitc::ATTR_KIND_SPECULATIVE_LOAD_HARDENING;
749   case Attribute::SwiftError:
750     return bitc::ATTR_KIND_SWIFT_ERROR;
751   case Attribute::SwiftSelf:
752     return bitc::ATTR_KIND_SWIFT_SELF;
753   case Attribute::SwiftAsync:
754     return bitc::ATTR_KIND_SWIFT_ASYNC;
755   case Attribute::UWTable:
756     return bitc::ATTR_KIND_UW_TABLE;
757   case Attribute::VScaleRange:
758     return bitc::ATTR_KIND_VSCALE_RANGE;
759   case Attribute::WillReturn:
760     return bitc::ATTR_KIND_WILLRETURN;
761   case Attribute::WriteOnly:
762     return bitc::ATTR_KIND_WRITEONLY;
763   case Attribute::ZExt:
764     return bitc::ATTR_KIND_Z_EXT;
765   case Attribute::ImmArg:
766     return bitc::ATTR_KIND_IMMARG;
767   case Attribute::SanitizeMemTag:
768     return bitc::ATTR_KIND_SANITIZE_MEMTAG;
769   case Attribute::Preallocated:
770     return bitc::ATTR_KIND_PREALLOCATED;
771   case Attribute::NoUndef:
772     return bitc::ATTR_KIND_NOUNDEF;
773   case Attribute::ByRef:
774     return bitc::ATTR_KIND_BYREF;
775   case Attribute::MustProgress:
776     return bitc::ATTR_KIND_MUSTPROGRESS;
777   case Attribute::EndAttrKinds:
778     llvm_unreachable("Can not encode end-attribute kinds marker.");
779   case Attribute::None:
780     llvm_unreachable("Can not encode none-attribute.");
781   case Attribute::EmptyKey:
782   case Attribute::TombstoneKey:
783     llvm_unreachable("Trying to encode EmptyKey/TombstoneKey");
784   }
785 
786   llvm_unreachable("Trying to encode unknown attribute");
787 }
788 
789 void ModuleBitcodeWriter::writeAttributeGroupTable() {
790   const std::vector<ValueEnumerator::IndexAndAttrSet> &AttrGrps =
791       VE.getAttributeGroups();
792   if (AttrGrps.empty()) return;
793 
794   Stream.EnterSubblock(bitc::PARAMATTR_GROUP_BLOCK_ID, 3);
795 
796   SmallVector<uint64_t, 64> Record;
797   for (ValueEnumerator::IndexAndAttrSet Pair : AttrGrps) {
798     unsigned AttrListIndex = Pair.first;
799     AttributeSet AS = Pair.second;
800     Record.push_back(VE.getAttributeGroupID(Pair));
801     Record.push_back(AttrListIndex);
802 
803     for (Attribute Attr : AS) {
804       if (Attr.isEnumAttribute()) {
805         Record.push_back(0);
806         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
807       } else if (Attr.isIntAttribute()) {
808         Record.push_back(1);
809         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
810         Record.push_back(Attr.getValueAsInt());
811       } else if (Attr.isStringAttribute()) {
812         StringRef Kind = Attr.getKindAsString();
813         StringRef Val = Attr.getValueAsString();
814 
815         Record.push_back(Val.empty() ? 3 : 4);
816         Record.append(Kind.begin(), Kind.end());
817         Record.push_back(0);
818         if (!Val.empty()) {
819           Record.append(Val.begin(), Val.end());
820           Record.push_back(0);
821         }
822       } else {
823         assert(Attr.isTypeAttribute());
824         Type *Ty = Attr.getValueAsType();
825         Record.push_back(Ty ? 6 : 5);
826         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
827         if (Ty)
828           Record.push_back(VE.getTypeID(Attr.getValueAsType()));
829       }
830     }
831 
832     Stream.EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
833     Record.clear();
834   }
835 
836   Stream.ExitBlock();
837 }
838 
839 void ModuleBitcodeWriter::writeAttributeTable() {
840   const std::vector<AttributeList> &Attrs = VE.getAttributeLists();
841   if (Attrs.empty()) return;
842 
843   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
844 
845   SmallVector<uint64_t, 64> Record;
846   for (const AttributeList &AL : Attrs) {
847     for (unsigned i : AL.indexes()) {
848       AttributeSet AS = AL.getAttributes(i);
849       if (AS.hasAttributes())
850         Record.push_back(VE.getAttributeGroupID({i, AS}));
851     }
852 
853     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
854     Record.clear();
855   }
856 
857   Stream.ExitBlock();
858 }
859 
860 /// WriteTypeTable - Write out the type table for a module.
861 void ModuleBitcodeWriter::writeTypeTable() {
862   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
863 
864   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
865   SmallVector<uint64_t, 64> TypeVals;
866 
867   uint64_t NumBits = VE.computeBitsRequiredForTypeIndicies();
868 
869   // Abbrev for TYPE_CODE_POINTER.
870   auto Abbv = std::make_shared<BitCodeAbbrev>();
871   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
872   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
873   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
874   unsigned PtrAbbrev = Stream.EmitAbbrev(std::move(Abbv));
875 
876   // Abbrev for TYPE_CODE_OPAQUE_POINTER.
877   Abbv = std::make_shared<BitCodeAbbrev>();
878   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_OPAQUE_POINTER));
879   Abbv->Add(BitCodeAbbrevOp(0)); // Addrspace = 0
880   unsigned OpaquePtrAbbrev = Stream.EmitAbbrev(std::move(Abbv));
881 
882   // Abbrev for TYPE_CODE_FUNCTION.
883   Abbv = std::make_shared<BitCodeAbbrev>();
884   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
885   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
886   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
887   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
888   unsigned FunctionAbbrev = Stream.EmitAbbrev(std::move(Abbv));
889 
890   // Abbrev for TYPE_CODE_STRUCT_ANON.
891   Abbv = std::make_shared<BitCodeAbbrev>();
892   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
893   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
894   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
895   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
896   unsigned StructAnonAbbrev = Stream.EmitAbbrev(std::move(Abbv));
897 
898   // Abbrev for TYPE_CODE_STRUCT_NAME.
899   Abbv = std::make_shared<BitCodeAbbrev>();
900   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
901   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
902   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
903   unsigned StructNameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
904 
905   // Abbrev for TYPE_CODE_STRUCT_NAMED.
906   Abbv = std::make_shared<BitCodeAbbrev>();
907   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
908   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
909   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
910   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
911   unsigned StructNamedAbbrev = Stream.EmitAbbrev(std::move(Abbv));
912 
913   // Abbrev for TYPE_CODE_ARRAY.
914   Abbv = std::make_shared<BitCodeAbbrev>();
915   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
916   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
917   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
918   unsigned ArrayAbbrev = Stream.EmitAbbrev(std::move(Abbv));
919 
920   // Emit an entry count so the reader can reserve space.
921   TypeVals.push_back(TypeList.size());
922   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
923   TypeVals.clear();
924 
925   // Loop over all of the types, emitting each in turn.
926   for (Type *T : TypeList) {
927     int AbbrevToUse = 0;
928     unsigned Code = 0;
929 
930     switch (T->getTypeID()) {
931     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;      break;
932     case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;      break;
933     case Type::BFloatTyID:    Code = bitc::TYPE_CODE_BFLOAT;    break;
934     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;     break;
935     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE;    break;
936     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80;  break;
937     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128;     break;
938     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
939     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;     break;
940     case Type::MetadataTyID:  Code = bitc::TYPE_CODE_METADATA;  break;
941     case Type::X86_MMXTyID:   Code = bitc::TYPE_CODE_X86_MMX;   break;
942     case Type::X86_AMXTyID:   Code = bitc::TYPE_CODE_X86_AMX;   break;
943     case Type::TokenTyID:     Code = bitc::TYPE_CODE_TOKEN;     break;
944     case Type::IntegerTyID:
945       // INTEGER: [width]
946       Code = bitc::TYPE_CODE_INTEGER;
947       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
948       break;
949     case Type::PointerTyID: {
950       PointerType *PTy = cast<PointerType>(T);
951       unsigned AddressSpace = PTy->getAddressSpace();
952       if (PTy->isOpaque()) {
953         // OPAQUE_POINTER: [address space]
954         Code = bitc::TYPE_CODE_OPAQUE_POINTER;
955         TypeVals.push_back(AddressSpace);
956         if (AddressSpace == 0)
957           AbbrevToUse = OpaquePtrAbbrev;
958       } else {
959         // POINTER: [pointee type, address space]
960         Code = bitc::TYPE_CODE_POINTER;
961         TypeVals.push_back(VE.getTypeID(PTy->getNonOpaquePointerElementType()));
962         TypeVals.push_back(AddressSpace);
963         if (AddressSpace == 0)
964           AbbrevToUse = PtrAbbrev;
965       }
966       break;
967     }
968     case Type::FunctionTyID: {
969       FunctionType *FT = cast<FunctionType>(T);
970       // FUNCTION: [isvararg, retty, paramty x N]
971       Code = bitc::TYPE_CODE_FUNCTION;
972       TypeVals.push_back(FT->isVarArg());
973       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
974       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
975         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
976       AbbrevToUse = FunctionAbbrev;
977       break;
978     }
979     case Type::StructTyID: {
980       StructType *ST = cast<StructType>(T);
981       // STRUCT: [ispacked, eltty x N]
982       TypeVals.push_back(ST->isPacked());
983       // Output all of the element types.
984       for (Type *ET : ST->elements())
985         TypeVals.push_back(VE.getTypeID(ET));
986 
987       if (ST->isLiteral()) {
988         Code = bitc::TYPE_CODE_STRUCT_ANON;
989         AbbrevToUse = StructAnonAbbrev;
990       } else {
991         if (ST->isOpaque()) {
992           Code = bitc::TYPE_CODE_OPAQUE;
993         } else {
994           Code = bitc::TYPE_CODE_STRUCT_NAMED;
995           AbbrevToUse = StructNamedAbbrev;
996         }
997 
998         // Emit the name if it is present.
999         if (!ST->getName().empty())
1000           writeStringRecord(Stream, bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
1001                             StructNameAbbrev);
1002       }
1003       break;
1004     }
1005     case Type::ArrayTyID: {
1006       ArrayType *AT = cast<ArrayType>(T);
1007       // ARRAY: [numelts, eltty]
1008       Code = bitc::TYPE_CODE_ARRAY;
1009       TypeVals.push_back(AT->getNumElements());
1010       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
1011       AbbrevToUse = ArrayAbbrev;
1012       break;
1013     }
1014     case Type::FixedVectorTyID:
1015     case Type::ScalableVectorTyID: {
1016       VectorType *VT = cast<VectorType>(T);
1017       // VECTOR [numelts, eltty] or
1018       //        [numelts, eltty, scalable]
1019       Code = bitc::TYPE_CODE_VECTOR;
1020       TypeVals.push_back(VT->getElementCount().getKnownMinValue());
1021       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
1022       if (isa<ScalableVectorType>(VT))
1023         TypeVals.push_back(true);
1024       break;
1025     }
1026     case Type::DXILPointerTyID:
1027       llvm_unreachable("DXIL pointers cannot be added to IR modules");
1028     }
1029 
1030     // Emit the finished record.
1031     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
1032     TypeVals.clear();
1033   }
1034 
1035   Stream.ExitBlock();
1036 }
1037 
1038 static unsigned getEncodedLinkage(const GlobalValue::LinkageTypes Linkage) {
1039   switch (Linkage) {
1040   case GlobalValue::ExternalLinkage:
1041     return 0;
1042   case GlobalValue::WeakAnyLinkage:
1043     return 16;
1044   case GlobalValue::AppendingLinkage:
1045     return 2;
1046   case GlobalValue::InternalLinkage:
1047     return 3;
1048   case GlobalValue::LinkOnceAnyLinkage:
1049     return 18;
1050   case GlobalValue::ExternalWeakLinkage:
1051     return 7;
1052   case GlobalValue::CommonLinkage:
1053     return 8;
1054   case GlobalValue::PrivateLinkage:
1055     return 9;
1056   case GlobalValue::WeakODRLinkage:
1057     return 17;
1058   case GlobalValue::LinkOnceODRLinkage:
1059     return 19;
1060   case GlobalValue::AvailableExternallyLinkage:
1061     return 12;
1062   }
1063   llvm_unreachable("Invalid linkage");
1064 }
1065 
1066 static unsigned getEncodedLinkage(const GlobalValue &GV) {
1067   return getEncodedLinkage(GV.getLinkage());
1068 }
1069 
1070 static uint64_t getEncodedFFlags(FunctionSummary::FFlags Flags) {
1071   uint64_t RawFlags = 0;
1072   RawFlags |= Flags.ReadNone;
1073   RawFlags |= (Flags.ReadOnly << 1);
1074   RawFlags |= (Flags.NoRecurse << 2);
1075   RawFlags |= (Flags.ReturnDoesNotAlias << 3);
1076   RawFlags |= (Flags.NoInline << 4);
1077   RawFlags |= (Flags.AlwaysInline << 5);
1078   RawFlags |= (Flags.NoUnwind << 6);
1079   RawFlags |= (Flags.MayThrow << 7);
1080   RawFlags |= (Flags.HasUnknownCall << 8);
1081   RawFlags |= (Flags.MustBeUnreachable << 9);
1082   return RawFlags;
1083 }
1084 
1085 // Decode the flags for GlobalValue in the summary. See getDecodedGVSummaryFlags
1086 // in BitcodeReader.cpp.
1087 static uint64_t getEncodedGVSummaryFlags(GlobalValueSummary::GVFlags Flags) {
1088   uint64_t RawFlags = 0;
1089 
1090   RawFlags |= Flags.NotEligibleToImport; // bool
1091   RawFlags |= (Flags.Live << 1);
1092   RawFlags |= (Flags.DSOLocal << 2);
1093   RawFlags |= (Flags.CanAutoHide << 3);
1094 
1095   // Linkage don't need to be remapped at that time for the summary. Any future
1096   // change to the getEncodedLinkage() function will need to be taken into
1097   // account here as well.
1098   RawFlags = (RawFlags << 4) | Flags.Linkage; // 4 bits
1099 
1100   RawFlags |= (Flags.Visibility << 8); // 2 bits
1101 
1102   return RawFlags;
1103 }
1104 
1105 static uint64_t getEncodedGVarFlags(GlobalVarSummary::GVarFlags Flags) {
1106   uint64_t RawFlags = Flags.MaybeReadOnly | (Flags.MaybeWriteOnly << 1) |
1107                       (Flags.Constant << 2) | Flags.VCallVisibility << 3;
1108   return RawFlags;
1109 }
1110 
1111 static unsigned getEncodedVisibility(const GlobalValue &GV) {
1112   switch (GV.getVisibility()) {
1113   case GlobalValue::DefaultVisibility:   return 0;
1114   case GlobalValue::HiddenVisibility:    return 1;
1115   case GlobalValue::ProtectedVisibility: return 2;
1116   }
1117   llvm_unreachable("Invalid visibility");
1118 }
1119 
1120 static unsigned getEncodedDLLStorageClass(const GlobalValue &GV) {
1121   switch (GV.getDLLStorageClass()) {
1122   case GlobalValue::DefaultStorageClass:   return 0;
1123   case GlobalValue::DLLImportStorageClass: return 1;
1124   case GlobalValue::DLLExportStorageClass: return 2;
1125   }
1126   llvm_unreachable("Invalid DLL storage class");
1127 }
1128 
1129 static unsigned getEncodedThreadLocalMode(const GlobalValue &GV) {
1130   switch (GV.getThreadLocalMode()) {
1131     case GlobalVariable::NotThreadLocal:         return 0;
1132     case GlobalVariable::GeneralDynamicTLSModel: return 1;
1133     case GlobalVariable::LocalDynamicTLSModel:   return 2;
1134     case GlobalVariable::InitialExecTLSModel:    return 3;
1135     case GlobalVariable::LocalExecTLSModel:      return 4;
1136   }
1137   llvm_unreachable("Invalid TLS model");
1138 }
1139 
1140 static unsigned getEncodedComdatSelectionKind(const Comdat &C) {
1141   switch (C.getSelectionKind()) {
1142   case Comdat::Any:
1143     return bitc::COMDAT_SELECTION_KIND_ANY;
1144   case Comdat::ExactMatch:
1145     return bitc::COMDAT_SELECTION_KIND_EXACT_MATCH;
1146   case Comdat::Largest:
1147     return bitc::COMDAT_SELECTION_KIND_LARGEST;
1148   case Comdat::NoDeduplicate:
1149     return bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES;
1150   case Comdat::SameSize:
1151     return bitc::COMDAT_SELECTION_KIND_SAME_SIZE;
1152   }
1153   llvm_unreachable("Invalid selection kind");
1154 }
1155 
1156 static unsigned getEncodedUnnamedAddr(const GlobalValue &GV) {
1157   switch (GV.getUnnamedAddr()) {
1158   case GlobalValue::UnnamedAddr::None:   return 0;
1159   case GlobalValue::UnnamedAddr::Local:  return 2;
1160   case GlobalValue::UnnamedAddr::Global: return 1;
1161   }
1162   llvm_unreachable("Invalid unnamed_addr");
1163 }
1164 
1165 size_t ModuleBitcodeWriter::addToStrtab(StringRef Str) {
1166   if (GenerateHash)
1167     Hasher.update(Str);
1168   return StrtabBuilder.add(Str);
1169 }
1170 
1171 void ModuleBitcodeWriter::writeComdats() {
1172   SmallVector<unsigned, 64> Vals;
1173   for (const Comdat *C : VE.getComdats()) {
1174     // COMDAT: [strtab offset, strtab size, selection_kind]
1175     Vals.push_back(addToStrtab(C->getName()));
1176     Vals.push_back(C->getName().size());
1177     Vals.push_back(getEncodedComdatSelectionKind(*C));
1178     Stream.EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
1179     Vals.clear();
1180   }
1181 }
1182 
1183 /// Write a record that will eventually hold the word offset of the
1184 /// module-level VST. For now the offset is 0, which will be backpatched
1185 /// after the real VST is written. Saves the bit offset to backpatch.
1186 void ModuleBitcodeWriter::writeValueSymbolTableForwardDecl() {
1187   // Write a placeholder value in for the offset of the real VST,
1188   // which is written after the function blocks so that it can include
1189   // the offset of each function. The placeholder offset will be
1190   // updated when the real VST is written.
1191   auto Abbv = std::make_shared<BitCodeAbbrev>();
1192   Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_VSTOFFSET));
1193   // Blocks are 32-bit aligned, so we can use a 32-bit word offset to
1194   // hold the real VST offset. Must use fixed instead of VBR as we don't
1195   // know how many VBR chunks to reserve ahead of time.
1196   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
1197   unsigned VSTOffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1198 
1199   // Emit the placeholder
1200   uint64_t Vals[] = {bitc::MODULE_CODE_VSTOFFSET, 0};
1201   Stream.EmitRecordWithAbbrev(VSTOffsetAbbrev, Vals);
1202 
1203   // Compute and save the bit offset to the placeholder, which will be
1204   // patched when the real VST is written. We can simply subtract the 32-bit
1205   // fixed size from the current bit number to get the location to backpatch.
1206   VSTOffsetPlaceholder = Stream.GetCurrentBitNo() - 32;
1207 }
1208 
1209 enum StringEncoding { SE_Char6, SE_Fixed7, SE_Fixed8 };
1210 
1211 /// Determine the encoding to use for the given string name and length.
1212 static StringEncoding getStringEncoding(StringRef Str) {
1213   bool isChar6 = true;
1214   for (char C : Str) {
1215     if (isChar6)
1216       isChar6 = BitCodeAbbrevOp::isChar6(C);
1217     if ((unsigned char)C & 128)
1218       // don't bother scanning the rest.
1219       return SE_Fixed8;
1220   }
1221   if (isChar6)
1222     return SE_Char6;
1223   return SE_Fixed7;
1224 }
1225 
1226 /// Emit top-level description of module, including target triple, inline asm,
1227 /// descriptors for global variables, and function prototype info.
1228 /// Returns the bit offset to backpatch with the location of the real VST.
1229 void ModuleBitcodeWriter::writeModuleInfo() {
1230   // Emit various pieces of data attached to a module.
1231   if (!M.getTargetTriple().empty())
1232     writeStringRecord(Stream, bitc::MODULE_CODE_TRIPLE, M.getTargetTriple(),
1233                       0 /*TODO*/);
1234   const std::string &DL = M.getDataLayoutStr();
1235   if (!DL.empty())
1236     writeStringRecord(Stream, bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/);
1237   if (!M.getModuleInlineAsm().empty())
1238     writeStringRecord(Stream, bitc::MODULE_CODE_ASM, M.getModuleInlineAsm(),
1239                       0 /*TODO*/);
1240 
1241   // Emit information about sections and GC, computing how many there are. Also
1242   // compute the maximum alignment value.
1243   std::map<std::string, unsigned> SectionMap;
1244   std::map<std::string, unsigned> GCMap;
1245   MaybeAlign MaxAlignment;
1246   unsigned MaxGlobalType = 0;
1247   const auto UpdateMaxAlignment = [&MaxAlignment](const MaybeAlign A) {
1248     if (A)
1249       MaxAlignment = !MaxAlignment ? *A : std::max(*MaxAlignment, *A);
1250   };
1251   for (const GlobalVariable &GV : M.globals()) {
1252     UpdateMaxAlignment(GV.getAlign());
1253     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getValueType()));
1254     if (GV.hasSection()) {
1255       // Give section names unique ID's.
1256       unsigned &Entry = SectionMap[std::string(GV.getSection())];
1257       if (!Entry) {
1258         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
1259                           0 /*TODO*/);
1260         Entry = SectionMap.size();
1261       }
1262     }
1263   }
1264   for (const Function &F : M) {
1265     UpdateMaxAlignment(F.getAlign());
1266     if (F.hasSection()) {
1267       // Give section names unique ID's.
1268       unsigned &Entry = SectionMap[std::string(F.getSection())];
1269       if (!Entry) {
1270         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
1271                           0 /*TODO*/);
1272         Entry = SectionMap.size();
1273       }
1274     }
1275     if (F.hasGC()) {
1276       // Same for GC names.
1277       unsigned &Entry = GCMap[F.getGC()];
1278       if (!Entry) {
1279         writeStringRecord(Stream, bitc::MODULE_CODE_GCNAME, F.getGC(),
1280                           0 /*TODO*/);
1281         Entry = GCMap.size();
1282       }
1283     }
1284   }
1285 
1286   // Emit abbrev for globals, now that we know # sections and max alignment.
1287   unsigned SimpleGVarAbbrev = 0;
1288   if (!M.global_empty()) {
1289     // Add an abbrev for common globals with no visibility or thread localness.
1290     auto Abbv = std::make_shared<BitCodeAbbrev>();
1291     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
1292     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1293     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1294     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1295                               Log2_32_Ceil(MaxGlobalType+1)));
1296     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddrSpace << 2
1297                                                            //| explicitType << 1
1298                                                            //| constant
1299     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Initializer.
1300     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // Linkage.
1301     if (!MaxAlignment)                                     // Alignment.
1302       Abbv->Add(BitCodeAbbrevOp(0));
1303     else {
1304       unsigned MaxEncAlignment = getEncodedAlign(MaxAlignment);
1305       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1306                                Log2_32_Ceil(MaxEncAlignment+1)));
1307     }
1308     if (SectionMap.empty())                                    // Section.
1309       Abbv->Add(BitCodeAbbrevOp(0));
1310     else
1311       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1312                                Log2_32_Ceil(SectionMap.size()+1)));
1313     // Don't bother emitting vis + thread local.
1314     SimpleGVarAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1315   }
1316 
1317   SmallVector<unsigned, 64> Vals;
1318   // Emit the module's source file name.
1319   {
1320     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
1321     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
1322     if (Bits == SE_Char6)
1323       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
1324     else if (Bits == SE_Fixed7)
1325       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
1326 
1327     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
1328     auto Abbv = std::make_shared<BitCodeAbbrev>();
1329     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
1330     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1331     Abbv->Add(AbbrevOpToUse);
1332     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1333 
1334     for (const auto P : M.getSourceFileName())
1335       Vals.push_back((unsigned char)P);
1336 
1337     // Emit the finished record.
1338     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
1339     Vals.clear();
1340   }
1341 
1342   // Emit the global variable information.
1343   for (const GlobalVariable &GV : M.globals()) {
1344     unsigned AbbrevToUse = 0;
1345 
1346     // GLOBALVAR: [strtab offset, strtab size, type, isconst, initid,
1347     //             linkage, alignment, section, visibility, threadlocal,
1348     //             unnamed_addr, externally_initialized, dllstorageclass,
1349     //             comdat, attributes, DSO_Local]
1350     Vals.push_back(addToStrtab(GV.getName()));
1351     Vals.push_back(GV.getName().size());
1352     Vals.push_back(VE.getTypeID(GV.getValueType()));
1353     Vals.push_back(GV.getType()->getAddressSpace() << 2 | 2 | GV.isConstant());
1354     Vals.push_back(GV.isDeclaration() ? 0 :
1355                    (VE.getValueID(GV.getInitializer()) + 1));
1356     Vals.push_back(getEncodedLinkage(GV));
1357     Vals.push_back(getEncodedAlign(GV.getAlign()));
1358     Vals.push_back(GV.hasSection() ? SectionMap[std::string(GV.getSection())]
1359                                    : 0);
1360     if (GV.isThreadLocal() ||
1361         GV.getVisibility() != GlobalValue::DefaultVisibility ||
1362         GV.getUnnamedAddr() != GlobalValue::UnnamedAddr::None ||
1363         GV.isExternallyInitialized() ||
1364         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
1365         GV.hasComdat() ||
1366         GV.hasAttributes() ||
1367         GV.isDSOLocal() ||
1368         GV.hasPartition()) {
1369       Vals.push_back(getEncodedVisibility(GV));
1370       Vals.push_back(getEncodedThreadLocalMode(GV));
1371       Vals.push_back(getEncodedUnnamedAddr(GV));
1372       Vals.push_back(GV.isExternallyInitialized());
1373       Vals.push_back(getEncodedDLLStorageClass(GV));
1374       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
1375 
1376       auto AL = GV.getAttributesAsList(AttributeList::FunctionIndex);
1377       Vals.push_back(VE.getAttributeListID(AL));
1378 
1379       Vals.push_back(GV.isDSOLocal());
1380       Vals.push_back(addToStrtab(GV.getPartition()));
1381       Vals.push_back(GV.getPartition().size());
1382     } else {
1383       AbbrevToUse = SimpleGVarAbbrev;
1384     }
1385 
1386     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
1387     Vals.clear();
1388   }
1389 
1390   // Emit the function proto information.
1391   for (const Function &F : M) {
1392     // FUNCTION:  [strtab offset, strtab size, type, callingconv, isproto,
1393     //             linkage, paramattrs, alignment, section, visibility, gc,
1394     //             unnamed_addr, prologuedata, dllstorageclass, comdat,
1395     //             prefixdata, personalityfn, DSO_Local, addrspace]
1396     Vals.push_back(addToStrtab(F.getName()));
1397     Vals.push_back(F.getName().size());
1398     Vals.push_back(VE.getTypeID(F.getFunctionType()));
1399     Vals.push_back(F.getCallingConv());
1400     Vals.push_back(F.isDeclaration());
1401     Vals.push_back(getEncodedLinkage(F));
1402     Vals.push_back(VE.getAttributeListID(F.getAttributes()));
1403     Vals.push_back(getEncodedAlign(F.getAlign()));
1404     Vals.push_back(F.hasSection() ? SectionMap[std::string(F.getSection())]
1405                                   : 0);
1406     Vals.push_back(getEncodedVisibility(F));
1407     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
1408     Vals.push_back(getEncodedUnnamedAddr(F));
1409     Vals.push_back(F.hasPrologueData() ? (VE.getValueID(F.getPrologueData()) + 1)
1410                                        : 0);
1411     Vals.push_back(getEncodedDLLStorageClass(F));
1412     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
1413     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
1414                                      : 0);
1415     Vals.push_back(
1416         F.hasPersonalityFn() ? (VE.getValueID(F.getPersonalityFn()) + 1) : 0);
1417 
1418     Vals.push_back(F.isDSOLocal());
1419     Vals.push_back(F.getAddressSpace());
1420     Vals.push_back(addToStrtab(F.getPartition()));
1421     Vals.push_back(F.getPartition().size());
1422 
1423     unsigned AbbrevToUse = 0;
1424     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
1425     Vals.clear();
1426   }
1427 
1428   // Emit the alias information.
1429   for (const GlobalAlias &A : M.aliases()) {
1430     // ALIAS: [strtab offset, strtab size, alias type, aliasee val#, linkage,
1431     //         visibility, dllstorageclass, threadlocal, unnamed_addr,
1432     //         DSO_Local]
1433     Vals.push_back(addToStrtab(A.getName()));
1434     Vals.push_back(A.getName().size());
1435     Vals.push_back(VE.getTypeID(A.getValueType()));
1436     Vals.push_back(A.getType()->getAddressSpace());
1437     Vals.push_back(VE.getValueID(A.getAliasee()));
1438     Vals.push_back(getEncodedLinkage(A));
1439     Vals.push_back(getEncodedVisibility(A));
1440     Vals.push_back(getEncodedDLLStorageClass(A));
1441     Vals.push_back(getEncodedThreadLocalMode(A));
1442     Vals.push_back(getEncodedUnnamedAddr(A));
1443     Vals.push_back(A.isDSOLocal());
1444     Vals.push_back(addToStrtab(A.getPartition()));
1445     Vals.push_back(A.getPartition().size());
1446 
1447     unsigned AbbrevToUse = 0;
1448     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
1449     Vals.clear();
1450   }
1451 
1452   // Emit the ifunc information.
1453   for (const GlobalIFunc &I : M.ifuncs()) {
1454     // IFUNC: [strtab offset, strtab size, ifunc type, address space, resolver
1455     //         val#, linkage, visibility, DSO_Local]
1456     Vals.push_back(addToStrtab(I.getName()));
1457     Vals.push_back(I.getName().size());
1458     Vals.push_back(VE.getTypeID(I.getValueType()));
1459     Vals.push_back(I.getType()->getAddressSpace());
1460     Vals.push_back(VE.getValueID(I.getResolver()));
1461     Vals.push_back(getEncodedLinkage(I));
1462     Vals.push_back(getEncodedVisibility(I));
1463     Vals.push_back(I.isDSOLocal());
1464     Vals.push_back(addToStrtab(I.getPartition()));
1465     Vals.push_back(I.getPartition().size());
1466     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
1467     Vals.clear();
1468   }
1469 
1470   writeValueSymbolTableForwardDecl();
1471 }
1472 
1473 static uint64_t getOptimizationFlags(const Value *V) {
1474   uint64_t Flags = 0;
1475 
1476   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
1477     if (OBO->hasNoSignedWrap())
1478       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
1479     if (OBO->hasNoUnsignedWrap())
1480       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
1481   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
1482     if (PEO->isExact())
1483       Flags |= 1 << bitc::PEO_EXACT;
1484   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
1485     if (FPMO->hasAllowReassoc())
1486       Flags |= bitc::AllowReassoc;
1487     if (FPMO->hasNoNaNs())
1488       Flags |= bitc::NoNaNs;
1489     if (FPMO->hasNoInfs())
1490       Flags |= bitc::NoInfs;
1491     if (FPMO->hasNoSignedZeros())
1492       Flags |= bitc::NoSignedZeros;
1493     if (FPMO->hasAllowReciprocal())
1494       Flags |= bitc::AllowReciprocal;
1495     if (FPMO->hasAllowContract())
1496       Flags |= bitc::AllowContract;
1497     if (FPMO->hasApproxFunc())
1498       Flags |= bitc::ApproxFunc;
1499   }
1500 
1501   return Flags;
1502 }
1503 
1504 void ModuleBitcodeWriter::writeValueAsMetadata(
1505     const ValueAsMetadata *MD, SmallVectorImpl<uint64_t> &Record) {
1506   // Mimic an MDNode with a value as one operand.
1507   Value *V = MD->getValue();
1508   Record.push_back(VE.getTypeID(V->getType()));
1509   Record.push_back(VE.getValueID(V));
1510   Stream.EmitRecord(bitc::METADATA_VALUE, Record, 0);
1511   Record.clear();
1512 }
1513 
1514 void ModuleBitcodeWriter::writeMDTuple(const MDTuple *N,
1515                                        SmallVectorImpl<uint64_t> &Record,
1516                                        unsigned Abbrev) {
1517   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
1518     Metadata *MD = N->getOperand(i);
1519     assert(!(MD && isa<LocalAsMetadata>(MD)) &&
1520            "Unexpected function-local metadata");
1521     Record.push_back(VE.getMetadataOrNullID(MD));
1522   }
1523   Stream.EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
1524                                     : bitc::METADATA_NODE,
1525                     Record, Abbrev);
1526   Record.clear();
1527 }
1528 
1529 unsigned ModuleBitcodeWriter::createDILocationAbbrev() {
1530   // Assume the column is usually under 128, and always output the inlined-at
1531   // location (it's never more expensive than building an array size 1).
1532   auto Abbv = std::make_shared<BitCodeAbbrev>();
1533   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
1534   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1535   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1536   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1537   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1538   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1539   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1540   return Stream.EmitAbbrev(std::move(Abbv));
1541 }
1542 
1543 void ModuleBitcodeWriter::writeDILocation(const DILocation *N,
1544                                           SmallVectorImpl<uint64_t> &Record,
1545                                           unsigned &Abbrev) {
1546   if (!Abbrev)
1547     Abbrev = createDILocationAbbrev();
1548 
1549   Record.push_back(N->isDistinct());
1550   Record.push_back(N->getLine());
1551   Record.push_back(N->getColumn());
1552   Record.push_back(VE.getMetadataID(N->getScope()));
1553   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
1554   Record.push_back(N->isImplicitCode());
1555 
1556   Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
1557   Record.clear();
1558 }
1559 
1560 unsigned ModuleBitcodeWriter::createGenericDINodeAbbrev() {
1561   // Assume the column is usually under 128, and always output the inlined-at
1562   // location (it's never more expensive than building an array size 1).
1563   auto Abbv = std::make_shared<BitCodeAbbrev>();
1564   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
1565   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1566   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1567   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1568   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1569   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1570   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1571   return Stream.EmitAbbrev(std::move(Abbv));
1572 }
1573 
1574 void ModuleBitcodeWriter::writeGenericDINode(const GenericDINode *N,
1575                                              SmallVectorImpl<uint64_t> &Record,
1576                                              unsigned &Abbrev) {
1577   if (!Abbrev)
1578     Abbrev = createGenericDINodeAbbrev();
1579 
1580   Record.push_back(N->isDistinct());
1581   Record.push_back(N->getTag());
1582   Record.push_back(0); // Per-tag version field; unused for now.
1583 
1584   for (auto &I : N->operands())
1585     Record.push_back(VE.getMetadataOrNullID(I));
1586 
1587   Stream.EmitRecord(bitc::METADATA_GENERIC_DEBUG, Record, Abbrev);
1588   Record.clear();
1589 }
1590 
1591 void ModuleBitcodeWriter::writeDISubrange(const DISubrange *N,
1592                                           SmallVectorImpl<uint64_t> &Record,
1593                                           unsigned Abbrev) {
1594   const uint64_t Version = 2 << 1;
1595   Record.push_back((uint64_t)N->isDistinct() | Version);
1596   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1597   Record.push_back(VE.getMetadataOrNullID(N->getRawLowerBound()));
1598   Record.push_back(VE.getMetadataOrNullID(N->getRawUpperBound()));
1599   Record.push_back(VE.getMetadataOrNullID(N->getRawStride()));
1600 
1601   Stream.EmitRecord(bitc::METADATA_SUBRANGE, Record, Abbrev);
1602   Record.clear();
1603 }
1604 
1605 void ModuleBitcodeWriter::writeDIGenericSubrange(
1606     const DIGenericSubrange *N, SmallVectorImpl<uint64_t> &Record,
1607     unsigned Abbrev) {
1608   Record.push_back((uint64_t)N->isDistinct());
1609   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1610   Record.push_back(VE.getMetadataOrNullID(N->getRawLowerBound()));
1611   Record.push_back(VE.getMetadataOrNullID(N->getRawUpperBound()));
1612   Record.push_back(VE.getMetadataOrNullID(N->getRawStride()));
1613 
1614   Stream.EmitRecord(bitc::METADATA_GENERIC_SUBRANGE, Record, Abbrev);
1615   Record.clear();
1616 }
1617 
1618 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
1619   if ((int64_t)V >= 0)
1620     Vals.push_back(V << 1);
1621   else
1622     Vals.push_back((-V << 1) | 1);
1623 }
1624 
1625 static void emitWideAPInt(SmallVectorImpl<uint64_t> &Vals, const APInt &A) {
1626   // We have an arbitrary precision integer value to write whose
1627   // bit width is > 64. However, in canonical unsigned integer
1628   // format it is likely that the high bits are going to be zero.
1629   // So, we only write the number of active words.
1630   unsigned NumWords = A.getActiveWords();
1631   const uint64_t *RawData = A.getRawData();
1632   for (unsigned i = 0; i < NumWords; i++)
1633     emitSignedInt64(Vals, RawData[i]);
1634 }
1635 
1636 void ModuleBitcodeWriter::writeDIEnumerator(const DIEnumerator *N,
1637                                             SmallVectorImpl<uint64_t> &Record,
1638                                             unsigned Abbrev) {
1639   const uint64_t IsBigInt = 1 << 2;
1640   Record.push_back(IsBigInt | (N->isUnsigned() << 1) | N->isDistinct());
1641   Record.push_back(N->getValue().getBitWidth());
1642   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1643   emitWideAPInt(Record, N->getValue());
1644 
1645   Stream.EmitRecord(bitc::METADATA_ENUMERATOR, Record, Abbrev);
1646   Record.clear();
1647 }
1648 
1649 void ModuleBitcodeWriter::writeDIBasicType(const DIBasicType *N,
1650                                            SmallVectorImpl<uint64_t> &Record,
1651                                            unsigned Abbrev) {
1652   Record.push_back(N->isDistinct());
1653   Record.push_back(N->getTag());
1654   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1655   Record.push_back(N->getSizeInBits());
1656   Record.push_back(N->getAlignInBits());
1657   Record.push_back(N->getEncoding());
1658   Record.push_back(N->getFlags());
1659 
1660   Stream.EmitRecord(bitc::METADATA_BASIC_TYPE, Record, Abbrev);
1661   Record.clear();
1662 }
1663 
1664 void ModuleBitcodeWriter::writeDIStringType(const DIStringType *N,
1665                                             SmallVectorImpl<uint64_t> &Record,
1666                                             unsigned Abbrev) {
1667   Record.push_back(N->isDistinct());
1668   Record.push_back(N->getTag());
1669   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1670   Record.push_back(VE.getMetadataOrNullID(N->getStringLength()));
1671   Record.push_back(VE.getMetadataOrNullID(N->getStringLengthExp()));
1672   Record.push_back(VE.getMetadataOrNullID(N->getStringLocationExp()));
1673   Record.push_back(N->getSizeInBits());
1674   Record.push_back(N->getAlignInBits());
1675   Record.push_back(N->getEncoding());
1676 
1677   Stream.EmitRecord(bitc::METADATA_STRING_TYPE, Record, Abbrev);
1678   Record.clear();
1679 }
1680 
1681 void ModuleBitcodeWriter::writeDIDerivedType(const DIDerivedType *N,
1682                                              SmallVectorImpl<uint64_t> &Record,
1683                                              unsigned Abbrev) {
1684   Record.push_back(N->isDistinct());
1685   Record.push_back(N->getTag());
1686   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1687   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1688   Record.push_back(N->getLine());
1689   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1690   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1691   Record.push_back(N->getSizeInBits());
1692   Record.push_back(N->getAlignInBits());
1693   Record.push_back(N->getOffsetInBits());
1694   Record.push_back(N->getFlags());
1695   Record.push_back(VE.getMetadataOrNullID(N->getExtraData()));
1696 
1697   // DWARF address space is encoded as N->getDWARFAddressSpace() + 1. 0 means
1698   // that there is no DWARF address space associated with DIDerivedType.
1699   if (const auto &DWARFAddressSpace = N->getDWARFAddressSpace())
1700     Record.push_back(*DWARFAddressSpace + 1);
1701   else
1702     Record.push_back(0);
1703 
1704   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1705 
1706   Stream.EmitRecord(bitc::METADATA_DERIVED_TYPE, Record, Abbrev);
1707   Record.clear();
1708 }
1709 
1710 void ModuleBitcodeWriter::writeDICompositeType(
1711     const DICompositeType *N, SmallVectorImpl<uint64_t> &Record,
1712     unsigned Abbrev) {
1713   const unsigned IsNotUsedInOldTypeRef = 0x2;
1714   Record.push_back(IsNotUsedInOldTypeRef | (unsigned)N->isDistinct());
1715   Record.push_back(N->getTag());
1716   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1717   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1718   Record.push_back(N->getLine());
1719   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1720   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1721   Record.push_back(N->getSizeInBits());
1722   Record.push_back(N->getAlignInBits());
1723   Record.push_back(N->getOffsetInBits());
1724   Record.push_back(N->getFlags());
1725   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1726   Record.push_back(N->getRuntimeLang());
1727   Record.push_back(VE.getMetadataOrNullID(N->getVTableHolder()));
1728   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1729   Record.push_back(VE.getMetadataOrNullID(N->getRawIdentifier()));
1730   Record.push_back(VE.getMetadataOrNullID(N->getDiscriminator()));
1731   Record.push_back(VE.getMetadataOrNullID(N->getRawDataLocation()));
1732   Record.push_back(VE.getMetadataOrNullID(N->getRawAssociated()));
1733   Record.push_back(VE.getMetadataOrNullID(N->getRawAllocated()));
1734   Record.push_back(VE.getMetadataOrNullID(N->getRawRank()));
1735   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1736 
1737   Stream.EmitRecord(bitc::METADATA_COMPOSITE_TYPE, Record, Abbrev);
1738   Record.clear();
1739 }
1740 
1741 void ModuleBitcodeWriter::writeDISubroutineType(
1742     const DISubroutineType *N, SmallVectorImpl<uint64_t> &Record,
1743     unsigned Abbrev) {
1744   const unsigned HasNoOldTypeRefs = 0x2;
1745   Record.push_back(HasNoOldTypeRefs | (unsigned)N->isDistinct());
1746   Record.push_back(N->getFlags());
1747   Record.push_back(VE.getMetadataOrNullID(N->getTypeArray().get()));
1748   Record.push_back(N->getCC());
1749 
1750   Stream.EmitRecord(bitc::METADATA_SUBROUTINE_TYPE, Record, Abbrev);
1751   Record.clear();
1752 }
1753 
1754 void ModuleBitcodeWriter::writeDIFile(const DIFile *N,
1755                                       SmallVectorImpl<uint64_t> &Record,
1756                                       unsigned Abbrev) {
1757   Record.push_back(N->isDistinct());
1758   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
1759   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
1760   if (N->getRawChecksum()) {
1761     Record.push_back(N->getRawChecksum()->Kind);
1762     Record.push_back(VE.getMetadataOrNullID(N->getRawChecksum()->Value));
1763   } else {
1764     // Maintain backwards compatibility with the old internal representation of
1765     // CSK_None in ChecksumKind by writing nulls here when Checksum is None.
1766     Record.push_back(0);
1767     Record.push_back(VE.getMetadataOrNullID(nullptr));
1768   }
1769   auto Source = N->getRawSource();
1770   if (Source)
1771     Record.push_back(VE.getMetadataOrNullID(*Source));
1772 
1773   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
1774   Record.clear();
1775 }
1776 
1777 void ModuleBitcodeWriter::writeDICompileUnit(const DICompileUnit *N,
1778                                              SmallVectorImpl<uint64_t> &Record,
1779                                              unsigned Abbrev) {
1780   assert(N->isDistinct() && "Expected distinct compile units");
1781   Record.push_back(/* IsDistinct */ true);
1782   Record.push_back(N->getSourceLanguage());
1783   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1784   Record.push_back(VE.getMetadataOrNullID(N->getRawProducer()));
1785   Record.push_back(N->isOptimized());
1786   Record.push_back(VE.getMetadataOrNullID(N->getRawFlags()));
1787   Record.push_back(N->getRuntimeVersion());
1788   Record.push_back(VE.getMetadataOrNullID(N->getRawSplitDebugFilename()));
1789   Record.push_back(N->getEmissionKind());
1790   Record.push_back(VE.getMetadataOrNullID(N->getEnumTypes().get()));
1791   Record.push_back(VE.getMetadataOrNullID(N->getRetainedTypes().get()));
1792   Record.push_back(/* subprograms */ 0);
1793   Record.push_back(VE.getMetadataOrNullID(N->getGlobalVariables().get()));
1794   Record.push_back(VE.getMetadataOrNullID(N->getImportedEntities().get()));
1795   Record.push_back(N->getDWOId());
1796   Record.push_back(VE.getMetadataOrNullID(N->getMacros().get()));
1797   Record.push_back(N->getSplitDebugInlining());
1798   Record.push_back(N->getDebugInfoForProfiling());
1799   Record.push_back((unsigned)N->getNameTableKind());
1800   Record.push_back(N->getRangesBaseAddress());
1801   Record.push_back(VE.getMetadataOrNullID(N->getRawSysRoot()));
1802   Record.push_back(VE.getMetadataOrNullID(N->getRawSDK()));
1803 
1804   Stream.EmitRecord(bitc::METADATA_COMPILE_UNIT, Record, Abbrev);
1805   Record.clear();
1806 }
1807 
1808 void ModuleBitcodeWriter::writeDISubprogram(const DISubprogram *N,
1809                                             SmallVectorImpl<uint64_t> &Record,
1810                                             unsigned Abbrev) {
1811   const uint64_t HasUnitFlag = 1 << 1;
1812   const uint64_t HasSPFlagsFlag = 1 << 2;
1813   Record.push_back(uint64_t(N->isDistinct()) | HasUnitFlag | HasSPFlagsFlag);
1814   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1815   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1816   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1817   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1818   Record.push_back(N->getLine());
1819   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1820   Record.push_back(N->getScopeLine());
1821   Record.push_back(VE.getMetadataOrNullID(N->getContainingType()));
1822   Record.push_back(N->getSPFlags());
1823   Record.push_back(N->getVirtualIndex());
1824   Record.push_back(N->getFlags());
1825   Record.push_back(VE.getMetadataOrNullID(N->getRawUnit()));
1826   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1827   Record.push_back(VE.getMetadataOrNullID(N->getDeclaration()));
1828   Record.push_back(VE.getMetadataOrNullID(N->getRetainedNodes().get()));
1829   Record.push_back(N->getThisAdjustment());
1830   Record.push_back(VE.getMetadataOrNullID(N->getThrownTypes().get()));
1831   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1832   Record.push_back(VE.getMetadataOrNullID(N->getRawTargetFuncName()));
1833 
1834   Stream.EmitRecord(bitc::METADATA_SUBPROGRAM, Record, Abbrev);
1835   Record.clear();
1836 }
1837 
1838 void ModuleBitcodeWriter::writeDILexicalBlock(const DILexicalBlock *N,
1839                                               SmallVectorImpl<uint64_t> &Record,
1840                                               unsigned Abbrev) {
1841   Record.push_back(N->isDistinct());
1842   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1843   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1844   Record.push_back(N->getLine());
1845   Record.push_back(N->getColumn());
1846 
1847   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK, Record, Abbrev);
1848   Record.clear();
1849 }
1850 
1851 void ModuleBitcodeWriter::writeDILexicalBlockFile(
1852     const DILexicalBlockFile *N, SmallVectorImpl<uint64_t> &Record,
1853     unsigned Abbrev) {
1854   Record.push_back(N->isDistinct());
1855   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1856   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1857   Record.push_back(N->getDiscriminator());
1858 
1859   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK_FILE, Record, Abbrev);
1860   Record.clear();
1861 }
1862 
1863 void ModuleBitcodeWriter::writeDICommonBlock(const DICommonBlock *N,
1864                                              SmallVectorImpl<uint64_t> &Record,
1865                                              unsigned Abbrev) {
1866   Record.push_back(N->isDistinct());
1867   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1868   Record.push_back(VE.getMetadataOrNullID(N->getDecl()));
1869   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1870   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1871   Record.push_back(N->getLineNo());
1872 
1873   Stream.EmitRecord(bitc::METADATA_COMMON_BLOCK, Record, Abbrev);
1874   Record.clear();
1875 }
1876 
1877 void ModuleBitcodeWriter::writeDINamespace(const DINamespace *N,
1878                                            SmallVectorImpl<uint64_t> &Record,
1879                                            unsigned Abbrev) {
1880   Record.push_back(N->isDistinct() | N->getExportSymbols() << 1);
1881   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1882   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1883 
1884   Stream.EmitRecord(bitc::METADATA_NAMESPACE, Record, Abbrev);
1885   Record.clear();
1886 }
1887 
1888 void ModuleBitcodeWriter::writeDIMacro(const DIMacro *N,
1889                                        SmallVectorImpl<uint64_t> &Record,
1890                                        unsigned Abbrev) {
1891   Record.push_back(N->isDistinct());
1892   Record.push_back(N->getMacinfoType());
1893   Record.push_back(N->getLine());
1894   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1895   Record.push_back(VE.getMetadataOrNullID(N->getRawValue()));
1896 
1897   Stream.EmitRecord(bitc::METADATA_MACRO, Record, Abbrev);
1898   Record.clear();
1899 }
1900 
1901 void ModuleBitcodeWriter::writeDIMacroFile(const DIMacroFile *N,
1902                                            SmallVectorImpl<uint64_t> &Record,
1903                                            unsigned Abbrev) {
1904   Record.push_back(N->isDistinct());
1905   Record.push_back(N->getMacinfoType());
1906   Record.push_back(N->getLine());
1907   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1908   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1909 
1910   Stream.EmitRecord(bitc::METADATA_MACRO_FILE, Record, Abbrev);
1911   Record.clear();
1912 }
1913 
1914 void ModuleBitcodeWriter::writeDIArgList(const DIArgList *N,
1915                                          SmallVectorImpl<uint64_t> &Record,
1916                                          unsigned Abbrev) {
1917   Record.reserve(N->getArgs().size());
1918   for (ValueAsMetadata *MD : N->getArgs())
1919     Record.push_back(VE.getMetadataID(MD));
1920 
1921   Stream.EmitRecord(bitc::METADATA_ARG_LIST, Record, Abbrev);
1922   Record.clear();
1923 }
1924 
1925 void ModuleBitcodeWriter::writeDIModule(const DIModule *N,
1926                                         SmallVectorImpl<uint64_t> &Record,
1927                                         unsigned Abbrev) {
1928   Record.push_back(N->isDistinct());
1929   for (auto &I : N->operands())
1930     Record.push_back(VE.getMetadataOrNullID(I));
1931   Record.push_back(N->getLineNo());
1932   Record.push_back(N->getIsDecl());
1933 
1934   Stream.EmitRecord(bitc::METADATA_MODULE, Record, Abbrev);
1935   Record.clear();
1936 }
1937 
1938 void ModuleBitcodeWriter::writeDITemplateTypeParameter(
1939     const DITemplateTypeParameter *N, SmallVectorImpl<uint64_t> &Record,
1940     unsigned Abbrev) {
1941   Record.push_back(N->isDistinct());
1942   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1943   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1944   Record.push_back(N->isDefault());
1945 
1946   Stream.EmitRecord(bitc::METADATA_TEMPLATE_TYPE, Record, Abbrev);
1947   Record.clear();
1948 }
1949 
1950 void ModuleBitcodeWriter::writeDITemplateValueParameter(
1951     const DITemplateValueParameter *N, SmallVectorImpl<uint64_t> &Record,
1952     unsigned Abbrev) {
1953   Record.push_back(N->isDistinct());
1954   Record.push_back(N->getTag());
1955   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1956   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1957   Record.push_back(N->isDefault());
1958   Record.push_back(VE.getMetadataOrNullID(N->getValue()));
1959 
1960   Stream.EmitRecord(bitc::METADATA_TEMPLATE_VALUE, Record, Abbrev);
1961   Record.clear();
1962 }
1963 
1964 void ModuleBitcodeWriter::writeDIGlobalVariable(
1965     const DIGlobalVariable *N, SmallVectorImpl<uint64_t> &Record,
1966     unsigned Abbrev) {
1967   const uint64_t Version = 2 << 1;
1968   Record.push_back((uint64_t)N->isDistinct() | Version);
1969   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1970   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1971   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1972   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1973   Record.push_back(N->getLine());
1974   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1975   Record.push_back(N->isLocalToUnit());
1976   Record.push_back(N->isDefinition());
1977   Record.push_back(VE.getMetadataOrNullID(N->getStaticDataMemberDeclaration()));
1978   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams()));
1979   Record.push_back(N->getAlignInBits());
1980   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1981 
1982   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR, Record, Abbrev);
1983   Record.clear();
1984 }
1985 
1986 void ModuleBitcodeWriter::writeDILocalVariable(
1987     const DILocalVariable *N, SmallVectorImpl<uint64_t> &Record,
1988     unsigned Abbrev) {
1989   // In order to support all possible bitcode formats in BitcodeReader we need
1990   // to distinguish the following cases:
1991   // 1) Record has no artificial tag (Record[1]),
1992   //   has no obsolete inlinedAt field (Record[9]).
1993   //   In this case Record size will be 8, HasAlignment flag is false.
1994   // 2) Record has artificial tag (Record[1]),
1995   //   has no obsolete inlignedAt field (Record[9]).
1996   //   In this case Record size will be 9, HasAlignment flag is false.
1997   // 3) Record has both artificial tag (Record[1]) and
1998   //   obsolete inlignedAt field (Record[9]).
1999   //   In this case Record size will be 10, HasAlignment flag is false.
2000   // 4) Record has neither artificial tag, nor inlignedAt field, but
2001   //   HasAlignment flag is true and Record[8] contains alignment value.
2002   const uint64_t HasAlignmentFlag = 1 << 1;
2003   Record.push_back((uint64_t)N->isDistinct() | HasAlignmentFlag);
2004   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2005   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2006   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2007   Record.push_back(N->getLine());
2008   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2009   Record.push_back(N->getArg());
2010   Record.push_back(N->getFlags());
2011   Record.push_back(N->getAlignInBits());
2012   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
2013 
2014   Stream.EmitRecord(bitc::METADATA_LOCAL_VAR, Record, Abbrev);
2015   Record.clear();
2016 }
2017 
2018 void ModuleBitcodeWriter::writeDILabel(
2019     const DILabel *N, SmallVectorImpl<uint64_t> &Record,
2020     unsigned Abbrev) {
2021   Record.push_back((uint64_t)N->isDistinct());
2022   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2023   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2024   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2025   Record.push_back(N->getLine());
2026 
2027   Stream.EmitRecord(bitc::METADATA_LABEL, Record, Abbrev);
2028   Record.clear();
2029 }
2030 
2031 void ModuleBitcodeWriter::writeDIExpression(const DIExpression *N,
2032                                             SmallVectorImpl<uint64_t> &Record,
2033                                             unsigned Abbrev) {
2034   Record.reserve(N->getElements().size() + 1);
2035   const uint64_t Version = 3 << 1;
2036   Record.push_back((uint64_t)N->isDistinct() | Version);
2037   Record.append(N->elements_begin(), N->elements_end());
2038 
2039   Stream.EmitRecord(bitc::METADATA_EXPRESSION, Record, Abbrev);
2040   Record.clear();
2041 }
2042 
2043 void ModuleBitcodeWriter::writeDIGlobalVariableExpression(
2044     const DIGlobalVariableExpression *N, SmallVectorImpl<uint64_t> &Record,
2045     unsigned Abbrev) {
2046   Record.push_back(N->isDistinct());
2047   Record.push_back(VE.getMetadataOrNullID(N->getVariable()));
2048   Record.push_back(VE.getMetadataOrNullID(N->getExpression()));
2049 
2050   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR_EXPR, Record, Abbrev);
2051   Record.clear();
2052 }
2053 
2054 void ModuleBitcodeWriter::writeDIObjCProperty(const DIObjCProperty *N,
2055                                               SmallVectorImpl<uint64_t> &Record,
2056                                               unsigned Abbrev) {
2057   Record.push_back(N->isDistinct());
2058   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2059   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2060   Record.push_back(N->getLine());
2061   Record.push_back(VE.getMetadataOrNullID(N->getRawSetterName()));
2062   Record.push_back(VE.getMetadataOrNullID(N->getRawGetterName()));
2063   Record.push_back(N->getAttributes());
2064   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2065 
2066   Stream.EmitRecord(bitc::METADATA_OBJC_PROPERTY, Record, Abbrev);
2067   Record.clear();
2068 }
2069 
2070 void ModuleBitcodeWriter::writeDIImportedEntity(
2071     const DIImportedEntity *N, SmallVectorImpl<uint64_t> &Record,
2072     unsigned Abbrev) {
2073   Record.push_back(N->isDistinct());
2074   Record.push_back(N->getTag());
2075   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2076   Record.push_back(VE.getMetadataOrNullID(N->getEntity()));
2077   Record.push_back(N->getLine());
2078   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2079   Record.push_back(VE.getMetadataOrNullID(N->getRawFile()));
2080   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
2081 
2082   Stream.EmitRecord(bitc::METADATA_IMPORTED_ENTITY, Record, Abbrev);
2083   Record.clear();
2084 }
2085 
2086 unsigned ModuleBitcodeWriter::createNamedMetadataAbbrev() {
2087   auto Abbv = std::make_shared<BitCodeAbbrev>();
2088   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
2089   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2090   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2091   return Stream.EmitAbbrev(std::move(Abbv));
2092 }
2093 
2094 void ModuleBitcodeWriter::writeNamedMetadata(
2095     SmallVectorImpl<uint64_t> &Record) {
2096   if (M.named_metadata_empty())
2097     return;
2098 
2099   unsigned Abbrev = createNamedMetadataAbbrev();
2100   for (const NamedMDNode &NMD : M.named_metadata()) {
2101     // Write name.
2102     StringRef Str = NMD.getName();
2103     Record.append(Str.bytes_begin(), Str.bytes_end());
2104     Stream.EmitRecord(bitc::METADATA_NAME, Record, Abbrev);
2105     Record.clear();
2106 
2107     // Write named metadata operands.
2108     for (const MDNode *N : NMD.operands())
2109       Record.push_back(VE.getMetadataID(N));
2110     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
2111     Record.clear();
2112   }
2113 }
2114 
2115 unsigned ModuleBitcodeWriter::createMetadataStringsAbbrev() {
2116   auto Abbv = std::make_shared<BitCodeAbbrev>();
2117   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRINGS));
2118   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // # of strings
2119   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // offset to chars
2120   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
2121   return Stream.EmitAbbrev(std::move(Abbv));
2122 }
2123 
2124 /// Write out a record for MDString.
2125 ///
2126 /// All the metadata strings in a metadata block are emitted in a single
2127 /// record.  The sizes and strings themselves are shoved into a blob.
2128 void ModuleBitcodeWriter::writeMetadataStrings(
2129     ArrayRef<const Metadata *> Strings, SmallVectorImpl<uint64_t> &Record) {
2130   if (Strings.empty())
2131     return;
2132 
2133   // Start the record with the number of strings.
2134   Record.push_back(bitc::METADATA_STRINGS);
2135   Record.push_back(Strings.size());
2136 
2137   // Emit the sizes of the strings in the blob.
2138   SmallString<256> Blob;
2139   {
2140     BitstreamWriter W(Blob);
2141     for (const Metadata *MD : Strings)
2142       W.EmitVBR(cast<MDString>(MD)->getLength(), 6);
2143     W.FlushToWord();
2144   }
2145 
2146   // Add the offset to the strings to the record.
2147   Record.push_back(Blob.size());
2148 
2149   // Add the strings to the blob.
2150   for (const Metadata *MD : Strings)
2151     Blob.append(cast<MDString>(MD)->getString());
2152 
2153   // Emit the final record.
2154   Stream.EmitRecordWithBlob(createMetadataStringsAbbrev(), Record, Blob);
2155   Record.clear();
2156 }
2157 
2158 // Generates an enum to use as an index in the Abbrev array of Metadata record.
2159 enum MetadataAbbrev : unsigned {
2160 #define HANDLE_MDNODE_LEAF(CLASS) CLASS##AbbrevID,
2161 #include "llvm/IR/Metadata.def"
2162   LastPlusOne
2163 };
2164 
2165 void ModuleBitcodeWriter::writeMetadataRecords(
2166     ArrayRef<const Metadata *> MDs, SmallVectorImpl<uint64_t> &Record,
2167     std::vector<unsigned> *MDAbbrevs, std::vector<uint64_t> *IndexPos) {
2168   if (MDs.empty())
2169     return;
2170 
2171   // Initialize MDNode abbreviations.
2172 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
2173 #include "llvm/IR/Metadata.def"
2174 
2175   for (const Metadata *MD : MDs) {
2176     if (IndexPos)
2177       IndexPos->push_back(Stream.GetCurrentBitNo());
2178     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
2179       assert(N->isResolved() && "Expected forward references to be resolved");
2180 
2181       switch (N->getMetadataID()) {
2182       default:
2183         llvm_unreachable("Invalid MDNode subclass");
2184 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
2185   case Metadata::CLASS##Kind:                                                  \
2186     if (MDAbbrevs)                                                             \
2187       write##CLASS(cast<CLASS>(N), Record,                                     \
2188                    (*MDAbbrevs)[MetadataAbbrev::CLASS##AbbrevID]);             \
2189     else                                                                       \
2190       write##CLASS(cast<CLASS>(N), Record, CLASS##Abbrev);                     \
2191     continue;
2192 #include "llvm/IR/Metadata.def"
2193       }
2194     }
2195     writeValueAsMetadata(cast<ValueAsMetadata>(MD), Record);
2196   }
2197 }
2198 
2199 void ModuleBitcodeWriter::writeModuleMetadata() {
2200   if (!VE.hasMDs() && M.named_metadata_empty())
2201     return;
2202 
2203   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 4);
2204   SmallVector<uint64_t, 64> Record;
2205 
2206   // Emit all abbrevs upfront, so that the reader can jump in the middle of the
2207   // block and load any metadata.
2208   std::vector<unsigned> MDAbbrevs;
2209 
2210   MDAbbrevs.resize(MetadataAbbrev::LastPlusOne);
2211   MDAbbrevs[MetadataAbbrev::DILocationAbbrevID] = createDILocationAbbrev();
2212   MDAbbrevs[MetadataAbbrev::GenericDINodeAbbrevID] =
2213       createGenericDINodeAbbrev();
2214 
2215   auto Abbv = std::make_shared<BitCodeAbbrev>();
2216   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX_OFFSET));
2217   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2218   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2219   unsigned OffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2220 
2221   Abbv = std::make_shared<BitCodeAbbrev>();
2222   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX));
2223   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2224   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2225   unsigned IndexAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2226 
2227   // Emit MDStrings together upfront.
2228   writeMetadataStrings(VE.getMDStrings(), Record);
2229 
2230   // We only emit an index for the metadata record if we have more than a given
2231   // (naive) threshold of metadatas, otherwise it is not worth it.
2232   if (VE.getNonMDStrings().size() > IndexThreshold) {
2233     // Write a placeholder value in for the offset of the metadata index,
2234     // which is written after the records, so that it can include
2235     // the offset of each entry. The placeholder offset will be
2236     // updated after all records are emitted.
2237     uint64_t Vals[] = {0, 0};
2238     Stream.EmitRecord(bitc::METADATA_INDEX_OFFSET, Vals, OffsetAbbrev);
2239   }
2240 
2241   // Compute and save the bit offset to the current position, which will be
2242   // patched when we emit the index later. We can simply subtract the 64-bit
2243   // fixed size from the current bit number to get the location to backpatch.
2244   uint64_t IndexOffsetRecordBitPos = Stream.GetCurrentBitNo();
2245 
2246   // This index will contain the bitpos for each individual record.
2247   std::vector<uint64_t> IndexPos;
2248   IndexPos.reserve(VE.getNonMDStrings().size());
2249 
2250   // Write all the records
2251   writeMetadataRecords(VE.getNonMDStrings(), Record, &MDAbbrevs, &IndexPos);
2252 
2253   if (VE.getNonMDStrings().size() > IndexThreshold) {
2254     // Now that we have emitted all the records we will emit the index. But
2255     // first
2256     // backpatch the forward reference so that the reader can skip the records
2257     // efficiently.
2258     Stream.BackpatchWord64(IndexOffsetRecordBitPos - 64,
2259                            Stream.GetCurrentBitNo() - IndexOffsetRecordBitPos);
2260 
2261     // Delta encode the index.
2262     uint64_t PreviousValue = IndexOffsetRecordBitPos;
2263     for (auto &Elt : IndexPos) {
2264       auto EltDelta = Elt - PreviousValue;
2265       PreviousValue = Elt;
2266       Elt = EltDelta;
2267     }
2268     // Emit the index record.
2269     Stream.EmitRecord(bitc::METADATA_INDEX, IndexPos, IndexAbbrev);
2270     IndexPos.clear();
2271   }
2272 
2273   // Write the named metadata now.
2274   writeNamedMetadata(Record);
2275 
2276   auto AddDeclAttachedMetadata = [&](const GlobalObject &GO) {
2277     SmallVector<uint64_t, 4> Record;
2278     Record.push_back(VE.getValueID(&GO));
2279     pushGlobalMetadataAttachment(Record, GO);
2280     Stream.EmitRecord(bitc::METADATA_GLOBAL_DECL_ATTACHMENT, Record);
2281   };
2282   for (const Function &F : M)
2283     if (F.isDeclaration() && F.hasMetadata())
2284       AddDeclAttachedMetadata(F);
2285   // FIXME: Only store metadata for declarations here, and move data for global
2286   // variable definitions to a separate block (PR28134).
2287   for (const GlobalVariable &GV : M.globals())
2288     if (GV.hasMetadata())
2289       AddDeclAttachedMetadata(GV);
2290 
2291   Stream.ExitBlock();
2292 }
2293 
2294 void ModuleBitcodeWriter::writeFunctionMetadata(const Function &F) {
2295   if (!VE.hasMDs())
2296     return;
2297 
2298   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
2299   SmallVector<uint64_t, 64> Record;
2300   writeMetadataStrings(VE.getMDStrings(), Record);
2301   writeMetadataRecords(VE.getNonMDStrings(), Record);
2302   Stream.ExitBlock();
2303 }
2304 
2305 void ModuleBitcodeWriter::pushGlobalMetadataAttachment(
2306     SmallVectorImpl<uint64_t> &Record, const GlobalObject &GO) {
2307   // [n x [id, mdnode]]
2308   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2309   GO.getAllMetadata(MDs);
2310   for (const auto &I : MDs) {
2311     Record.push_back(I.first);
2312     Record.push_back(VE.getMetadataID(I.second));
2313   }
2314 }
2315 
2316 void ModuleBitcodeWriter::writeFunctionMetadataAttachment(const Function &F) {
2317   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
2318 
2319   SmallVector<uint64_t, 64> Record;
2320 
2321   if (F.hasMetadata()) {
2322     pushGlobalMetadataAttachment(Record, F);
2323     Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2324     Record.clear();
2325   }
2326 
2327   // Write metadata attachments
2328   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
2329   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2330   for (const BasicBlock &BB : F)
2331     for (const Instruction &I : BB) {
2332       MDs.clear();
2333       I.getAllMetadataOtherThanDebugLoc(MDs);
2334 
2335       // If no metadata, ignore instruction.
2336       if (MDs.empty()) continue;
2337 
2338       Record.push_back(VE.getInstructionID(&I));
2339 
2340       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
2341         Record.push_back(MDs[i].first);
2342         Record.push_back(VE.getMetadataID(MDs[i].second));
2343       }
2344       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2345       Record.clear();
2346     }
2347 
2348   Stream.ExitBlock();
2349 }
2350 
2351 void ModuleBitcodeWriter::writeModuleMetadataKinds() {
2352   SmallVector<uint64_t, 64> Record;
2353 
2354   // Write metadata kinds
2355   // METADATA_KIND - [n x [id, name]]
2356   SmallVector<StringRef, 8> Names;
2357   M.getMDKindNames(Names);
2358 
2359   if (Names.empty()) return;
2360 
2361   Stream.EnterSubblock(bitc::METADATA_KIND_BLOCK_ID, 3);
2362 
2363   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
2364     Record.push_back(MDKindID);
2365     StringRef KName = Names[MDKindID];
2366     Record.append(KName.begin(), KName.end());
2367 
2368     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
2369     Record.clear();
2370   }
2371 
2372   Stream.ExitBlock();
2373 }
2374 
2375 void ModuleBitcodeWriter::writeOperandBundleTags() {
2376   // Write metadata kinds
2377   //
2378   // OPERAND_BUNDLE_TAGS_BLOCK_ID : N x OPERAND_BUNDLE_TAG
2379   //
2380   // OPERAND_BUNDLE_TAG - [strchr x N]
2381 
2382   SmallVector<StringRef, 8> Tags;
2383   M.getOperandBundleTags(Tags);
2384 
2385   if (Tags.empty())
2386     return;
2387 
2388   Stream.EnterSubblock(bitc::OPERAND_BUNDLE_TAGS_BLOCK_ID, 3);
2389 
2390   SmallVector<uint64_t, 64> Record;
2391 
2392   for (auto Tag : Tags) {
2393     Record.append(Tag.begin(), Tag.end());
2394 
2395     Stream.EmitRecord(bitc::OPERAND_BUNDLE_TAG, Record, 0);
2396     Record.clear();
2397   }
2398 
2399   Stream.ExitBlock();
2400 }
2401 
2402 void ModuleBitcodeWriter::writeSyncScopeNames() {
2403   SmallVector<StringRef, 8> SSNs;
2404   M.getContext().getSyncScopeNames(SSNs);
2405   if (SSNs.empty())
2406     return;
2407 
2408   Stream.EnterSubblock(bitc::SYNC_SCOPE_NAMES_BLOCK_ID, 2);
2409 
2410   SmallVector<uint64_t, 64> Record;
2411   for (auto SSN : SSNs) {
2412     Record.append(SSN.begin(), SSN.end());
2413     Stream.EmitRecord(bitc::SYNC_SCOPE_NAME, Record, 0);
2414     Record.clear();
2415   }
2416 
2417   Stream.ExitBlock();
2418 }
2419 
2420 void ModuleBitcodeWriter::writeConstants(unsigned FirstVal, unsigned LastVal,
2421                                          bool isGlobal) {
2422   if (FirstVal == LastVal) return;
2423 
2424   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
2425 
2426   unsigned AggregateAbbrev = 0;
2427   unsigned String8Abbrev = 0;
2428   unsigned CString7Abbrev = 0;
2429   unsigned CString6Abbrev = 0;
2430   // If this is a constant pool for the module, emit module-specific abbrevs.
2431   if (isGlobal) {
2432     // Abbrev for CST_CODE_AGGREGATE.
2433     auto Abbv = std::make_shared<BitCodeAbbrev>();
2434     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
2435     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2436     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
2437     AggregateAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2438 
2439     // Abbrev for CST_CODE_STRING.
2440     Abbv = std::make_shared<BitCodeAbbrev>();
2441     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
2442     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2443     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2444     String8Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2445     // Abbrev for CST_CODE_CSTRING.
2446     Abbv = std::make_shared<BitCodeAbbrev>();
2447     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2448     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2449     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2450     CString7Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2451     // Abbrev for CST_CODE_CSTRING.
2452     Abbv = std::make_shared<BitCodeAbbrev>();
2453     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2454     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2455     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2456     CString6Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2457   }
2458 
2459   SmallVector<uint64_t, 64> Record;
2460 
2461   const ValueEnumerator::ValueList &Vals = VE.getValues();
2462   Type *LastTy = nullptr;
2463   for (unsigned i = FirstVal; i != LastVal; ++i) {
2464     const Value *V = Vals[i].first;
2465     // If we need to switch types, do so now.
2466     if (V->getType() != LastTy) {
2467       LastTy = V->getType();
2468       Record.push_back(VE.getTypeID(LastTy));
2469       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
2470                         CONSTANTS_SETTYPE_ABBREV);
2471       Record.clear();
2472     }
2473 
2474     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
2475       Record.push_back(VE.getTypeID(IA->getFunctionType()));
2476       Record.push_back(
2477           unsigned(IA->hasSideEffects()) | unsigned(IA->isAlignStack()) << 1 |
2478           unsigned(IA->getDialect() & 1) << 2 | unsigned(IA->canThrow()) << 3);
2479 
2480       // Add the asm string.
2481       const std::string &AsmStr = IA->getAsmString();
2482       Record.push_back(AsmStr.size());
2483       Record.append(AsmStr.begin(), AsmStr.end());
2484 
2485       // Add the constraint string.
2486       const std::string &ConstraintStr = IA->getConstraintString();
2487       Record.push_back(ConstraintStr.size());
2488       Record.append(ConstraintStr.begin(), ConstraintStr.end());
2489       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
2490       Record.clear();
2491       continue;
2492     }
2493     const Constant *C = cast<Constant>(V);
2494     unsigned Code = -1U;
2495     unsigned AbbrevToUse = 0;
2496     if (C->isNullValue()) {
2497       Code = bitc::CST_CODE_NULL;
2498     } else if (isa<PoisonValue>(C)) {
2499       Code = bitc::CST_CODE_POISON;
2500     } else if (isa<UndefValue>(C)) {
2501       Code = bitc::CST_CODE_UNDEF;
2502     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
2503       if (IV->getBitWidth() <= 64) {
2504         uint64_t V = IV->getSExtValue();
2505         emitSignedInt64(Record, V);
2506         Code = bitc::CST_CODE_INTEGER;
2507         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
2508       } else {                             // Wide integers, > 64 bits in size.
2509         emitWideAPInt(Record, IV->getValue());
2510         Code = bitc::CST_CODE_WIDE_INTEGER;
2511       }
2512     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
2513       Code = bitc::CST_CODE_FLOAT;
2514       Type *Ty = CFP->getType();
2515       if (Ty->isHalfTy() || Ty->isBFloatTy() || Ty->isFloatTy() ||
2516           Ty->isDoubleTy()) {
2517         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
2518       } else if (Ty->isX86_FP80Ty()) {
2519         // api needed to prevent premature destruction
2520         // bits are not in the same order as a normal i80 APInt, compensate.
2521         APInt api = CFP->getValueAPF().bitcastToAPInt();
2522         const uint64_t *p = api.getRawData();
2523         Record.push_back((p[1] << 48) | (p[0] >> 16));
2524         Record.push_back(p[0] & 0xffffLL);
2525       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
2526         APInt api = CFP->getValueAPF().bitcastToAPInt();
2527         const uint64_t *p = api.getRawData();
2528         Record.push_back(p[0]);
2529         Record.push_back(p[1]);
2530       } else {
2531         assert(0 && "Unknown FP type!");
2532       }
2533     } else if (isa<ConstantDataSequential>(C) &&
2534                cast<ConstantDataSequential>(C)->isString()) {
2535       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
2536       // Emit constant strings specially.
2537       unsigned NumElts = Str->getNumElements();
2538       // If this is a null-terminated string, use the denser CSTRING encoding.
2539       if (Str->isCString()) {
2540         Code = bitc::CST_CODE_CSTRING;
2541         --NumElts;  // Don't encode the null, which isn't allowed by char6.
2542       } else {
2543         Code = bitc::CST_CODE_STRING;
2544         AbbrevToUse = String8Abbrev;
2545       }
2546       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
2547       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
2548       for (unsigned i = 0; i != NumElts; ++i) {
2549         unsigned char V = Str->getElementAsInteger(i);
2550         Record.push_back(V);
2551         isCStr7 &= (V & 128) == 0;
2552         if (isCStrChar6)
2553           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
2554       }
2555 
2556       if (isCStrChar6)
2557         AbbrevToUse = CString6Abbrev;
2558       else if (isCStr7)
2559         AbbrevToUse = CString7Abbrev;
2560     } else if (const ConstantDataSequential *CDS =
2561                   dyn_cast<ConstantDataSequential>(C)) {
2562       Code = bitc::CST_CODE_DATA;
2563       Type *EltTy = CDS->getElementType();
2564       if (isa<IntegerType>(EltTy)) {
2565         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2566           Record.push_back(CDS->getElementAsInteger(i));
2567       } else {
2568         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2569           Record.push_back(
2570               CDS->getElementAsAPFloat(i).bitcastToAPInt().getLimitedValue());
2571       }
2572     } else if (isa<ConstantAggregate>(C)) {
2573       Code = bitc::CST_CODE_AGGREGATE;
2574       for (const Value *Op : C->operands())
2575         Record.push_back(VE.getValueID(Op));
2576       AbbrevToUse = AggregateAbbrev;
2577     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
2578       switch (CE->getOpcode()) {
2579       default:
2580         if (Instruction::isCast(CE->getOpcode())) {
2581           Code = bitc::CST_CODE_CE_CAST;
2582           Record.push_back(getEncodedCastOpcode(CE->getOpcode()));
2583           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2584           Record.push_back(VE.getValueID(C->getOperand(0)));
2585           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
2586         } else {
2587           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
2588           Code = bitc::CST_CODE_CE_BINOP;
2589           Record.push_back(getEncodedBinaryOpcode(CE->getOpcode()));
2590           Record.push_back(VE.getValueID(C->getOperand(0)));
2591           Record.push_back(VE.getValueID(C->getOperand(1)));
2592           uint64_t Flags = getOptimizationFlags(CE);
2593           if (Flags != 0)
2594             Record.push_back(Flags);
2595         }
2596         break;
2597       case Instruction::FNeg: {
2598         assert(CE->getNumOperands() == 1 && "Unknown constant expr!");
2599         Code = bitc::CST_CODE_CE_UNOP;
2600         Record.push_back(getEncodedUnaryOpcode(CE->getOpcode()));
2601         Record.push_back(VE.getValueID(C->getOperand(0)));
2602         uint64_t Flags = getOptimizationFlags(CE);
2603         if (Flags != 0)
2604           Record.push_back(Flags);
2605         break;
2606       }
2607       case Instruction::GetElementPtr: {
2608         Code = bitc::CST_CODE_CE_GEP;
2609         const auto *GO = cast<GEPOperator>(C);
2610         Record.push_back(VE.getTypeID(GO->getSourceElementType()));
2611         if (Optional<unsigned> Idx = GO->getInRangeIndex()) {
2612           Code = bitc::CST_CODE_CE_GEP_WITH_INRANGE_INDEX;
2613           Record.push_back((*Idx << 1) | GO->isInBounds());
2614         } else if (GO->isInBounds())
2615           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
2616         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
2617           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
2618           Record.push_back(VE.getValueID(C->getOperand(i)));
2619         }
2620         break;
2621       }
2622       case Instruction::Select:
2623         Code = bitc::CST_CODE_CE_SELECT;
2624         Record.push_back(VE.getValueID(C->getOperand(0)));
2625         Record.push_back(VE.getValueID(C->getOperand(1)));
2626         Record.push_back(VE.getValueID(C->getOperand(2)));
2627         break;
2628       case Instruction::ExtractElement:
2629         Code = bitc::CST_CODE_CE_EXTRACTELT;
2630         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2631         Record.push_back(VE.getValueID(C->getOperand(0)));
2632         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
2633         Record.push_back(VE.getValueID(C->getOperand(1)));
2634         break;
2635       case Instruction::InsertElement:
2636         Code = bitc::CST_CODE_CE_INSERTELT;
2637         Record.push_back(VE.getValueID(C->getOperand(0)));
2638         Record.push_back(VE.getValueID(C->getOperand(1)));
2639         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
2640         Record.push_back(VE.getValueID(C->getOperand(2)));
2641         break;
2642       case Instruction::ShuffleVector:
2643         // If the return type and argument types are the same, this is a
2644         // standard shufflevector instruction.  If the types are different,
2645         // then the shuffle is widening or truncating the input vectors, and
2646         // the argument type must also be encoded.
2647         if (C->getType() == C->getOperand(0)->getType()) {
2648           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
2649         } else {
2650           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
2651           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2652         }
2653         Record.push_back(VE.getValueID(C->getOperand(0)));
2654         Record.push_back(VE.getValueID(C->getOperand(1)));
2655         Record.push_back(VE.getValueID(CE->getShuffleMaskForBitcode()));
2656         break;
2657       case Instruction::ICmp:
2658       case Instruction::FCmp:
2659         Code = bitc::CST_CODE_CE_CMP;
2660         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2661         Record.push_back(VE.getValueID(C->getOperand(0)));
2662         Record.push_back(VE.getValueID(C->getOperand(1)));
2663         Record.push_back(CE->getPredicate());
2664         break;
2665       case Instruction::ExtractValue:
2666       case Instruction::InsertValue:
2667         report_fatal_error("extractvalue/insertvalue constexprs not supported");
2668         break;
2669       }
2670     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
2671       Code = bitc::CST_CODE_BLOCKADDRESS;
2672       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
2673       Record.push_back(VE.getValueID(BA->getFunction()));
2674       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
2675     } else if (const auto *Equiv = dyn_cast<DSOLocalEquivalent>(C)) {
2676       Code = bitc::CST_CODE_DSO_LOCAL_EQUIVALENT;
2677       Record.push_back(VE.getTypeID(Equiv->getGlobalValue()->getType()));
2678       Record.push_back(VE.getValueID(Equiv->getGlobalValue()));
2679     } else if (const auto *NC = dyn_cast<NoCFIValue>(C)) {
2680       Code = bitc::CST_CODE_NO_CFI_VALUE;
2681       Record.push_back(VE.getTypeID(NC->getGlobalValue()->getType()));
2682       Record.push_back(VE.getValueID(NC->getGlobalValue()));
2683     } else {
2684 #ifndef NDEBUG
2685       C->dump();
2686 #endif
2687       llvm_unreachable("Unknown constant!");
2688     }
2689     Stream.EmitRecord(Code, Record, AbbrevToUse);
2690     Record.clear();
2691   }
2692 
2693   Stream.ExitBlock();
2694 }
2695 
2696 void ModuleBitcodeWriter::writeModuleConstants() {
2697   const ValueEnumerator::ValueList &Vals = VE.getValues();
2698 
2699   // Find the first constant to emit, which is the first non-globalvalue value.
2700   // We know globalvalues have been emitted by WriteModuleInfo.
2701   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
2702     if (!isa<GlobalValue>(Vals[i].first)) {
2703       writeConstants(i, Vals.size(), true);
2704       return;
2705     }
2706   }
2707 }
2708 
2709 /// pushValueAndType - The file has to encode both the value and type id for
2710 /// many values, because we need to know what type to create for forward
2711 /// references.  However, most operands are not forward references, so this type
2712 /// field is not needed.
2713 ///
2714 /// This function adds V's value ID to Vals.  If the value ID is higher than the
2715 /// instruction ID, then it is a forward reference, and it also includes the
2716 /// type ID.  The value ID that is written is encoded relative to the InstID.
2717 bool ModuleBitcodeWriter::pushValueAndType(const Value *V, unsigned InstID,
2718                                            SmallVectorImpl<unsigned> &Vals) {
2719   unsigned ValID = VE.getValueID(V);
2720   // Make encoding relative to the InstID.
2721   Vals.push_back(InstID - ValID);
2722   if (ValID >= InstID) {
2723     Vals.push_back(VE.getTypeID(V->getType()));
2724     return true;
2725   }
2726   return false;
2727 }
2728 
2729 void ModuleBitcodeWriter::writeOperandBundles(const CallBase &CS,
2730                                               unsigned InstID) {
2731   SmallVector<unsigned, 64> Record;
2732   LLVMContext &C = CS.getContext();
2733 
2734   for (unsigned i = 0, e = CS.getNumOperandBundles(); i != e; ++i) {
2735     const auto &Bundle = CS.getOperandBundleAt(i);
2736     Record.push_back(C.getOperandBundleTagID(Bundle.getTagName()));
2737 
2738     for (auto &Input : Bundle.Inputs)
2739       pushValueAndType(Input, InstID, Record);
2740 
2741     Stream.EmitRecord(bitc::FUNC_CODE_OPERAND_BUNDLE, Record);
2742     Record.clear();
2743   }
2744 }
2745 
2746 /// pushValue - Like pushValueAndType, but where the type of the value is
2747 /// omitted (perhaps it was already encoded in an earlier operand).
2748 void ModuleBitcodeWriter::pushValue(const Value *V, unsigned InstID,
2749                                     SmallVectorImpl<unsigned> &Vals) {
2750   unsigned ValID = VE.getValueID(V);
2751   Vals.push_back(InstID - ValID);
2752 }
2753 
2754 void ModuleBitcodeWriter::pushValueSigned(const Value *V, unsigned InstID,
2755                                           SmallVectorImpl<uint64_t> &Vals) {
2756   unsigned ValID = VE.getValueID(V);
2757   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
2758   emitSignedInt64(Vals, diff);
2759 }
2760 
2761 /// WriteInstruction - Emit an instruction to the specified stream.
2762 void ModuleBitcodeWriter::writeInstruction(const Instruction &I,
2763                                            unsigned InstID,
2764                                            SmallVectorImpl<unsigned> &Vals) {
2765   unsigned Code = 0;
2766   unsigned AbbrevToUse = 0;
2767   VE.setInstructionID(&I);
2768   switch (I.getOpcode()) {
2769   default:
2770     if (Instruction::isCast(I.getOpcode())) {
2771       Code = bitc::FUNC_CODE_INST_CAST;
2772       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2773         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
2774       Vals.push_back(VE.getTypeID(I.getType()));
2775       Vals.push_back(getEncodedCastOpcode(I.getOpcode()));
2776     } else {
2777       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
2778       Code = bitc::FUNC_CODE_INST_BINOP;
2779       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2780         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
2781       pushValue(I.getOperand(1), InstID, Vals);
2782       Vals.push_back(getEncodedBinaryOpcode(I.getOpcode()));
2783       uint64_t Flags = getOptimizationFlags(&I);
2784       if (Flags != 0) {
2785         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
2786           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
2787         Vals.push_back(Flags);
2788       }
2789     }
2790     break;
2791   case Instruction::FNeg: {
2792     Code = bitc::FUNC_CODE_INST_UNOP;
2793     if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2794       AbbrevToUse = FUNCTION_INST_UNOP_ABBREV;
2795     Vals.push_back(getEncodedUnaryOpcode(I.getOpcode()));
2796     uint64_t Flags = getOptimizationFlags(&I);
2797     if (Flags != 0) {
2798       if (AbbrevToUse == FUNCTION_INST_UNOP_ABBREV)
2799         AbbrevToUse = FUNCTION_INST_UNOP_FLAGS_ABBREV;
2800       Vals.push_back(Flags);
2801     }
2802     break;
2803   }
2804   case Instruction::GetElementPtr: {
2805     Code = bitc::FUNC_CODE_INST_GEP;
2806     AbbrevToUse = FUNCTION_INST_GEP_ABBREV;
2807     auto &GEPInst = cast<GetElementPtrInst>(I);
2808     Vals.push_back(GEPInst.isInBounds());
2809     Vals.push_back(VE.getTypeID(GEPInst.getSourceElementType()));
2810     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
2811       pushValueAndType(I.getOperand(i), InstID, Vals);
2812     break;
2813   }
2814   case Instruction::ExtractValue: {
2815     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
2816     pushValueAndType(I.getOperand(0), InstID, Vals);
2817     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
2818     Vals.append(EVI->idx_begin(), EVI->idx_end());
2819     break;
2820   }
2821   case Instruction::InsertValue: {
2822     Code = bitc::FUNC_CODE_INST_INSERTVAL;
2823     pushValueAndType(I.getOperand(0), InstID, Vals);
2824     pushValueAndType(I.getOperand(1), InstID, Vals);
2825     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
2826     Vals.append(IVI->idx_begin(), IVI->idx_end());
2827     break;
2828   }
2829   case Instruction::Select: {
2830     Code = bitc::FUNC_CODE_INST_VSELECT;
2831     pushValueAndType(I.getOperand(1), InstID, Vals);
2832     pushValue(I.getOperand(2), InstID, Vals);
2833     pushValueAndType(I.getOperand(0), InstID, Vals);
2834     uint64_t Flags = getOptimizationFlags(&I);
2835     if (Flags != 0)
2836       Vals.push_back(Flags);
2837     break;
2838   }
2839   case Instruction::ExtractElement:
2840     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
2841     pushValueAndType(I.getOperand(0), InstID, Vals);
2842     pushValueAndType(I.getOperand(1), InstID, Vals);
2843     break;
2844   case Instruction::InsertElement:
2845     Code = bitc::FUNC_CODE_INST_INSERTELT;
2846     pushValueAndType(I.getOperand(0), InstID, Vals);
2847     pushValue(I.getOperand(1), InstID, Vals);
2848     pushValueAndType(I.getOperand(2), InstID, Vals);
2849     break;
2850   case Instruction::ShuffleVector:
2851     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
2852     pushValueAndType(I.getOperand(0), InstID, Vals);
2853     pushValue(I.getOperand(1), InstID, Vals);
2854     pushValue(cast<ShuffleVectorInst>(I).getShuffleMaskForBitcode(), InstID,
2855               Vals);
2856     break;
2857   case Instruction::ICmp:
2858   case Instruction::FCmp: {
2859     // compare returning Int1Ty or vector of Int1Ty
2860     Code = bitc::FUNC_CODE_INST_CMP2;
2861     pushValueAndType(I.getOperand(0), InstID, Vals);
2862     pushValue(I.getOperand(1), InstID, Vals);
2863     Vals.push_back(cast<CmpInst>(I).getPredicate());
2864     uint64_t Flags = getOptimizationFlags(&I);
2865     if (Flags != 0)
2866       Vals.push_back(Flags);
2867     break;
2868   }
2869 
2870   case Instruction::Ret:
2871     {
2872       Code = bitc::FUNC_CODE_INST_RET;
2873       unsigned NumOperands = I.getNumOperands();
2874       if (NumOperands == 0)
2875         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
2876       else if (NumOperands == 1) {
2877         if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2878           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
2879       } else {
2880         for (unsigned i = 0, e = NumOperands; i != e; ++i)
2881           pushValueAndType(I.getOperand(i), InstID, Vals);
2882       }
2883     }
2884     break;
2885   case Instruction::Br:
2886     {
2887       Code = bitc::FUNC_CODE_INST_BR;
2888       const BranchInst &II = cast<BranchInst>(I);
2889       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
2890       if (II.isConditional()) {
2891         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
2892         pushValue(II.getCondition(), InstID, Vals);
2893       }
2894     }
2895     break;
2896   case Instruction::Switch:
2897     {
2898       Code = bitc::FUNC_CODE_INST_SWITCH;
2899       const SwitchInst &SI = cast<SwitchInst>(I);
2900       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
2901       pushValue(SI.getCondition(), InstID, Vals);
2902       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
2903       for (auto Case : SI.cases()) {
2904         Vals.push_back(VE.getValueID(Case.getCaseValue()));
2905         Vals.push_back(VE.getValueID(Case.getCaseSuccessor()));
2906       }
2907     }
2908     break;
2909   case Instruction::IndirectBr:
2910     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
2911     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2912     // Encode the address operand as relative, but not the basic blocks.
2913     pushValue(I.getOperand(0), InstID, Vals);
2914     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
2915       Vals.push_back(VE.getValueID(I.getOperand(i)));
2916     break;
2917 
2918   case Instruction::Invoke: {
2919     const InvokeInst *II = cast<InvokeInst>(&I);
2920     const Value *Callee = II->getCalledOperand();
2921     FunctionType *FTy = II->getFunctionType();
2922 
2923     if (II->hasOperandBundles())
2924       writeOperandBundles(*II, InstID);
2925 
2926     Code = bitc::FUNC_CODE_INST_INVOKE;
2927 
2928     Vals.push_back(VE.getAttributeListID(II->getAttributes()));
2929     Vals.push_back(II->getCallingConv() | 1 << 13);
2930     Vals.push_back(VE.getValueID(II->getNormalDest()));
2931     Vals.push_back(VE.getValueID(II->getUnwindDest()));
2932     Vals.push_back(VE.getTypeID(FTy));
2933     pushValueAndType(Callee, InstID, Vals);
2934 
2935     // Emit value #'s for the fixed parameters.
2936     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
2937       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
2938 
2939     // Emit type/value pairs for varargs params.
2940     if (FTy->isVarArg()) {
2941       for (unsigned i = FTy->getNumParams(), e = II->arg_size(); i != e; ++i)
2942         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
2943     }
2944     break;
2945   }
2946   case Instruction::Resume:
2947     Code = bitc::FUNC_CODE_INST_RESUME;
2948     pushValueAndType(I.getOperand(0), InstID, Vals);
2949     break;
2950   case Instruction::CleanupRet: {
2951     Code = bitc::FUNC_CODE_INST_CLEANUPRET;
2952     const auto &CRI = cast<CleanupReturnInst>(I);
2953     pushValue(CRI.getCleanupPad(), InstID, Vals);
2954     if (CRI.hasUnwindDest())
2955       Vals.push_back(VE.getValueID(CRI.getUnwindDest()));
2956     break;
2957   }
2958   case Instruction::CatchRet: {
2959     Code = bitc::FUNC_CODE_INST_CATCHRET;
2960     const auto &CRI = cast<CatchReturnInst>(I);
2961     pushValue(CRI.getCatchPad(), InstID, Vals);
2962     Vals.push_back(VE.getValueID(CRI.getSuccessor()));
2963     break;
2964   }
2965   case Instruction::CleanupPad:
2966   case Instruction::CatchPad: {
2967     const auto &FuncletPad = cast<FuncletPadInst>(I);
2968     Code = isa<CatchPadInst>(FuncletPad) ? bitc::FUNC_CODE_INST_CATCHPAD
2969                                          : bitc::FUNC_CODE_INST_CLEANUPPAD;
2970     pushValue(FuncletPad.getParentPad(), InstID, Vals);
2971 
2972     unsigned NumArgOperands = FuncletPad.getNumArgOperands();
2973     Vals.push_back(NumArgOperands);
2974     for (unsigned Op = 0; Op != NumArgOperands; ++Op)
2975       pushValueAndType(FuncletPad.getArgOperand(Op), InstID, Vals);
2976     break;
2977   }
2978   case Instruction::CatchSwitch: {
2979     Code = bitc::FUNC_CODE_INST_CATCHSWITCH;
2980     const auto &CatchSwitch = cast<CatchSwitchInst>(I);
2981 
2982     pushValue(CatchSwitch.getParentPad(), InstID, Vals);
2983 
2984     unsigned NumHandlers = CatchSwitch.getNumHandlers();
2985     Vals.push_back(NumHandlers);
2986     for (const BasicBlock *CatchPadBB : CatchSwitch.handlers())
2987       Vals.push_back(VE.getValueID(CatchPadBB));
2988 
2989     if (CatchSwitch.hasUnwindDest())
2990       Vals.push_back(VE.getValueID(CatchSwitch.getUnwindDest()));
2991     break;
2992   }
2993   case Instruction::CallBr: {
2994     const CallBrInst *CBI = cast<CallBrInst>(&I);
2995     const Value *Callee = CBI->getCalledOperand();
2996     FunctionType *FTy = CBI->getFunctionType();
2997 
2998     if (CBI->hasOperandBundles())
2999       writeOperandBundles(*CBI, InstID);
3000 
3001     Code = bitc::FUNC_CODE_INST_CALLBR;
3002 
3003     Vals.push_back(VE.getAttributeListID(CBI->getAttributes()));
3004 
3005     Vals.push_back(CBI->getCallingConv() << bitc::CALL_CCONV |
3006                    1 << bitc::CALL_EXPLICIT_TYPE);
3007 
3008     Vals.push_back(VE.getValueID(CBI->getDefaultDest()));
3009     Vals.push_back(CBI->getNumIndirectDests());
3010     for (unsigned i = 0, e = CBI->getNumIndirectDests(); i != e; ++i)
3011       Vals.push_back(VE.getValueID(CBI->getIndirectDest(i)));
3012 
3013     Vals.push_back(VE.getTypeID(FTy));
3014     pushValueAndType(Callee, InstID, Vals);
3015 
3016     // Emit value #'s for the fixed parameters.
3017     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
3018       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
3019 
3020     // Emit type/value pairs for varargs params.
3021     if (FTy->isVarArg()) {
3022       for (unsigned i = FTy->getNumParams(), e = CBI->arg_size(); i != e; ++i)
3023         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
3024     }
3025     break;
3026   }
3027   case Instruction::Unreachable:
3028     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
3029     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
3030     break;
3031 
3032   case Instruction::PHI: {
3033     const PHINode &PN = cast<PHINode>(I);
3034     Code = bitc::FUNC_CODE_INST_PHI;
3035     // With the newer instruction encoding, forward references could give
3036     // negative valued IDs.  This is most common for PHIs, so we use
3037     // signed VBRs.
3038     SmallVector<uint64_t, 128> Vals64;
3039     Vals64.push_back(VE.getTypeID(PN.getType()));
3040     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
3041       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64);
3042       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
3043     }
3044 
3045     uint64_t Flags = getOptimizationFlags(&I);
3046     if (Flags != 0)
3047       Vals64.push_back(Flags);
3048 
3049     // Emit a Vals64 vector and exit.
3050     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
3051     Vals64.clear();
3052     return;
3053   }
3054 
3055   case Instruction::LandingPad: {
3056     const LandingPadInst &LP = cast<LandingPadInst>(I);
3057     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
3058     Vals.push_back(VE.getTypeID(LP.getType()));
3059     Vals.push_back(LP.isCleanup());
3060     Vals.push_back(LP.getNumClauses());
3061     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
3062       if (LP.isCatch(I))
3063         Vals.push_back(LandingPadInst::Catch);
3064       else
3065         Vals.push_back(LandingPadInst::Filter);
3066       pushValueAndType(LP.getClause(I), InstID, Vals);
3067     }
3068     break;
3069   }
3070 
3071   case Instruction::Alloca: {
3072     Code = bitc::FUNC_CODE_INST_ALLOCA;
3073     const AllocaInst &AI = cast<AllocaInst>(I);
3074     Vals.push_back(VE.getTypeID(AI.getAllocatedType()));
3075     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
3076     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
3077     using APV = AllocaPackedValues;
3078     unsigned Record = 0;
3079     unsigned EncodedAlign = getEncodedAlign(AI.getAlign());
3080     Bitfield::set<APV::AlignLower>(
3081         Record, EncodedAlign & ((1 << APV::AlignLower::Bits) - 1));
3082     Bitfield::set<APV::AlignUpper>(Record,
3083                                    EncodedAlign >> APV::AlignLower::Bits);
3084     Bitfield::set<APV::UsedWithInAlloca>(Record, AI.isUsedWithInAlloca());
3085     Bitfield::set<APV::ExplicitType>(Record, true);
3086     Bitfield::set<APV::SwiftError>(Record, AI.isSwiftError());
3087     Vals.push_back(Record);
3088 
3089     unsigned AS = AI.getAddressSpace();
3090     if (AS != M.getDataLayout().getAllocaAddrSpace())
3091       Vals.push_back(AS);
3092     break;
3093   }
3094 
3095   case Instruction::Load:
3096     if (cast<LoadInst>(I).isAtomic()) {
3097       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
3098       pushValueAndType(I.getOperand(0), InstID, Vals);
3099     } else {
3100       Code = bitc::FUNC_CODE_INST_LOAD;
3101       if (!pushValueAndType(I.getOperand(0), InstID, Vals)) // ptr
3102         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
3103     }
3104     Vals.push_back(VE.getTypeID(I.getType()));
3105     Vals.push_back(getEncodedAlign(cast<LoadInst>(I).getAlign()));
3106     Vals.push_back(cast<LoadInst>(I).isVolatile());
3107     if (cast<LoadInst>(I).isAtomic()) {
3108       Vals.push_back(getEncodedOrdering(cast<LoadInst>(I).getOrdering()));
3109       Vals.push_back(getEncodedSyncScopeID(cast<LoadInst>(I).getSyncScopeID()));
3110     }
3111     break;
3112   case Instruction::Store:
3113     if (cast<StoreInst>(I).isAtomic())
3114       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
3115     else
3116       Code = bitc::FUNC_CODE_INST_STORE;
3117     pushValueAndType(I.getOperand(1), InstID, Vals); // ptrty + ptr
3118     pushValueAndType(I.getOperand(0), InstID, Vals); // valty + val
3119     Vals.push_back(getEncodedAlign(cast<StoreInst>(I).getAlign()));
3120     Vals.push_back(cast<StoreInst>(I).isVolatile());
3121     if (cast<StoreInst>(I).isAtomic()) {
3122       Vals.push_back(getEncodedOrdering(cast<StoreInst>(I).getOrdering()));
3123       Vals.push_back(
3124           getEncodedSyncScopeID(cast<StoreInst>(I).getSyncScopeID()));
3125     }
3126     break;
3127   case Instruction::AtomicCmpXchg:
3128     Code = bitc::FUNC_CODE_INST_CMPXCHG;
3129     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
3130     pushValueAndType(I.getOperand(1), InstID, Vals); // cmp.
3131     pushValue(I.getOperand(2), InstID, Vals);        // newval.
3132     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
3133     Vals.push_back(
3134         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
3135     Vals.push_back(
3136         getEncodedSyncScopeID(cast<AtomicCmpXchgInst>(I).getSyncScopeID()));
3137     Vals.push_back(
3138         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
3139     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
3140     Vals.push_back(getEncodedAlign(cast<AtomicCmpXchgInst>(I).getAlign()));
3141     break;
3142   case Instruction::AtomicRMW:
3143     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
3144     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
3145     pushValueAndType(I.getOperand(1), InstID, Vals); // valty + val
3146     Vals.push_back(
3147         getEncodedRMWOperation(cast<AtomicRMWInst>(I).getOperation()));
3148     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
3149     Vals.push_back(getEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
3150     Vals.push_back(
3151         getEncodedSyncScopeID(cast<AtomicRMWInst>(I).getSyncScopeID()));
3152     Vals.push_back(getEncodedAlign(cast<AtomicRMWInst>(I).getAlign()));
3153     break;
3154   case Instruction::Fence:
3155     Code = bitc::FUNC_CODE_INST_FENCE;
3156     Vals.push_back(getEncodedOrdering(cast<FenceInst>(I).getOrdering()));
3157     Vals.push_back(getEncodedSyncScopeID(cast<FenceInst>(I).getSyncScopeID()));
3158     break;
3159   case Instruction::Call: {
3160     const CallInst &CI = cast<CallInst>(I);
3161     FunctionType *FTy = CI.getFunctionType();
3162 
3163     if (CI.hasOperandBundles())
3164       writeOperandBundles(CI, InstID);
3165 
3166     Code = bitc::FUNC_CODE_INST_CALL;
3167 
3168     Vals.push_back(VE.getAttributeListID(CI.getAttributes()));
3169 
3170     unsigned Flags = getOptimizationFlags(&I);
3171     Vals.push_back(CI.getCallingConv() << bitc::CALL_CCONV |
3172                    unsigned(CI.isTailCall()) << bitc::CALL_TAIL |
3173                    unsigned(CI.isMustTailCall()) << bitc::CALL_MUSTTAIL |
3174                    1 << bitc::CALL_EXPLICIT_TYPE |
3175                    unsigned(CI.isNoTailCall()) << bitc::CALL_NOTAIL |
3176                    unsigned(Flags != 0) << bitc::CALL_FMF);
3177     if (Flags != 0)
3178       Vals.push_back(Flags);
3179 
3180     Vals.push_back(VE.getTypeID(FTy));
3181     pushValueAndType(CI.getCalledOperand(), InstID, Vals); // Callee
3182 
3183     // Emit value #'s for the fixed parameters.
3184     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
3185       // Check for labels (can happen with asm labels).
3186       if (FTy->getParamType(i)->isLabelTy())
3187         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
3188       else
3189         pushValue(CI.getArgOperand(i), InstID, Vals); // fixed param.
3190     }
3191 
3192     // Emit type/value pairs for varargs params.
3193     if (FTy->isVarArg()) {
3194       for (unsigned i = FTy->getNumParams(), e = CI.arg_size(); i != e; ++i)
3195         pushValueAndType(CI.getArgOperand(i), InstID, Vals); // varargs
3196     }
3197     break;
3198   }
3199   case Instruction::VAArg:
3200     Code = bitc::FUNC_CODE_INST_VAARG;
3201     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
3202     pushValue(I.getOperand(0), InstID, Vals);                   // valist.
3203     Vals.push_back(VE.getTypeID(I.getType())); // restype.
3204     break;
3205   case Instruction::Freeze:
3206     Code = bitc::FUNC_CODE_INST_FREEZE;
3207     pushValueAndType(I.getOperand(0), InstID, Vals);
3208     break;
3209   }
3210 
3211   Stream.EmitRecord(Code, Vals, AbbrevToUse);
3212   Vals.clear();
3213 }
3214 
3215 /// Write a GlobalValue VST to the module. The purpose of this data structure is
3216 /// to allow clients to efficiently find the function body.
3217 void ModuleBitcodeWriter::writeGlobalValueSymbolTable(
3218   DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3219   // Get the offset of the VST we are writing, and backpatch it into
3220   // the VST forward declaration record.
3221   uint64_t VSTOffset = Stream.GetCurrentBitNo();
3222   // The BitcodeStartBit was the stream offset of the identification block.
3223   VSTOffset -= bitcodeStartBit();
3224   assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
3225   // Note that we add 1 here because the offset is relative to one word
3226   // before the start of the identification block, which was historically
3227   // always the start of the regular bitcode header.
3228   Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32 + 1);
3229 
3230   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3231 
3232   auto Abbv = std::make_shared<BitCodeAbbrev>();
3233   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
3234   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
3235   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
3236   unsigned FnEntryAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3237 
3238   for (const Function &F : M) {
3239     uint64_t Record[2];
3240 
3241     if (F.isDeclaration())
3242       continue;
3243 
3244     Record[0] = VE.getValueID(&F);
3245 
3246     // Save the word offset of the function (from the start of the
3247     // actual bitcode written to the stream).
3248     uint64_t BitcodeIndex = FunctionToBitcodeIndex[&F] - bitcodeStartBit();
3249     assert((BitcodeIndex & 31) == 0 && "function block not 32-bit aligned");
3250     // Note that we add 1 here because the offset is relative to one word
3251     // before the start of the identification block, which was historically
3252     // always the start of the regular bitcode header.
3253     Record[1] = BitcodeIndex / 32 + 1;
3254 
3255     Stream.EmitRecord(bitc::VST_CODE_FNENTRY, Record, FnEntryAbbrev);
3256   }
3257 
3258   Stream.ExitBlock();
3259 }
3260 
3261 /// Emit names for arguments, instructions and basic blocks in a function.
3262 void ModuleBitcodeWriter::writeFunctionLevelValueSymbolTable(
3263     const ValueSymbolTable &VST) {
3264   if (VST.empty())
3265     return;
3266 
3267   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3268 
3269   // FIXME: Set up the abbrev, we know how many values there are!
3270   // FIXME: We know if the type names can use 7-bit ascii.
3271   SmallVector<uint64_t, 64> NameVals;
3272 
3273   for (const ValueName &Name : VST) {
3274     // Figure out the encoding to use for the name.
3275     StringEncoding Bits = getStringEncoding(Name.getKey());
3276 
3277     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
3278     NameVals.push_back(VE.getValueID(Name.getValue()));
3279 
3280     // VST_CODE_ENTRY:   [valueid, namechar x N]
3281     // VST_CODE_BBENTRY: [bbid, namechar x N]
3282     unsigned Code;
3283     if (isa<BasicBlock>(Name.getValue())) {
3284       Code = bitc::VST_CODE_BBENTRY;
3285       if (Bits == SE_Char6)
3286         AbbrevToUse = VST_BBENTRY_6_ABBREV;
3287     } else {
3288       Code = bitc::VST_CODE_ENTRY;
3289       if (Bits == SE_Char6)
3290         AbbrevToUse = VST_ENTRY_6_ABBREV;
3291       else if (Bits == SE_Fixed7)
3292         AbbrevToUse = VST_ENTRY_7_ABBREV;
3293     }
3294 
3295     for (const auto P : Name.getKey())
3296       NameVals.push_back((unsigned char)P);
3297 
3298     // Emit the finished record.
3299     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
3300     NameVals.clear();
3301   }
3302 
3303   Stream.ExitBlock();
3304 }
3305 
3306 void ModuleBitcodeWriter::writeUseList(UseListOrder &&Order) {
3307   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
3308   unsigned Code;
3309   if (isa<BasicBlock>(Order.V))
3310     Code = bitc::USELIST_CODE_BB;
3311   else
3312     Code = bitc::USELIST_CODE_DEFAULT;
3313 
3314   SmallVector<uint64_t, 64> Record(Order.Shuffle.begin(), Order.Shuffle.end());
3315   Record.push_back(VE.getValueID(Order.V));
3316   Stream.EmitRecord(Code, Record);
3317 }
3318 
3319 void ModuleBitcodeWriter::writeUseListBlock(const Function *F) {
3320   assert(VE.shouldPreserveUseListOrder() &&
3321          "Expected to be preserving use-list order");
3322 
3323   auto hasMore = [&]() {
3324     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
3325   };
3326   if (!hasMore())
3327     // Nothing to do.
3328     return;
3329 
3330   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
3331   while (hasMore()) {
3332     writeUseList(std::move(VE.UseListOrders.back()));
3333     VE.UseListOrders.pop_back();
3334   }
3335   Stream.ExitBlock();
3336 }
3337 
3338 /// Emit a function body to the module stream.
3339 void ModuleBitcodeWriter::writeFunction(
3340     const Function &F,
3341     DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3342   // Save the bitcode index of the start of this function block for recording
3343   // in the VST.
3344   FunctionToBitcodeIndex[&F] = Stream.GetCurrentBitNo();
3345 
3346   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
3347   VE.incorporateFunction(F);
3348 
3349   SmallVector<unsigned, 64> Vals;
3350 
3351   // Emit the number of basic blocks, so the reader can create them ahead of
3352   // time.
3353   Vals.push_back(VE.getBasicBlocks().size());
3354   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
3355   Vals.clear();
3356 
3357   // If there are function-local constants, emit them now.
3358   unsigned CstStart, CstEnd;
3359   VE.getFunctionConstantRange(CstStart, CstEnd);
3360   writeConstants(CstStart, CstEnd, false);
3361 
3362   // If there is function-local metadata, emit it now.
3363   writeFunctionMetadata(F);
3364 
3365   // Keep a running idea of what the instruction ID is.
3366   unsigned InstID = CstEnd;
3367 
3368   bool NeedsMetadataAttachment = F.hasMetadata();
3369 
3370   DILocation *LastDL = nullptr;
3371   SmallSetVector<Function *, 4> BlockAddressUsers;
3372 
3373   // Finally, emit all the instructions, in order.
3374   for (const BasicBlock &BB : F) {
3375     for (const Instruction &I : BB) {
3376       writeInstruction(I, InstID, Vals);
3377 
3378       if (!I.getType()->isVoidTy())
3379         ++InstID;
3380 
3381       // If the instruction has metadata, write a metadata attachment later.
3382       NeedsMetadataAttachment |= I.hasMetadataOtherThanDebugLoc();
3383 
3384       // If the instruction has a debug location, emit it.
3385       DILocation *DL = I.getDebugLoc();
3386       if (!DL)
3387         continue;
3388 
3389       if (DL == LastDL) {
3390         // Just repeat the same debug loc as last time.
3391         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
3392         continue;
3393       }
3394 
3395       Vals.push_back(DL->getLine());
3396       Vals.push_back(DL->getColumn());
3397       Vals.push_back(VE.getMetadataOrNullID(DL->getScope()));
3398       Vals.push_back(VE.getMetadataOrNullID(DL->getInlinedAt()));
3399       Vals.push_back(DL->isImplicitCode());
3400       Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
3401       Vals.clear();
3402 
3403       LastDL = DL;
3404     }
3405 
3406     if (BlockAddress *BA = BlockAddress::lookup(&BB)) {
3407       SmallVector<Value *> Worklist{BA};
3408       SmallPtrSet<Value *, 8> Visited{BA};
3409       while (!Worklist.empty()) {
3410         Value *V = Worklist.pop_back_val();
3411         for (User *U : V->users()) {
3412           if (auto *I = dyn_cast<Instruction>(U)) {
3413             Function *P = I->getFunction();
3414             if (P != &F)
3415               BlockAddressUsers.insert(P);
3416           } else if (isa<Constant>(U) && !isa<GlobalValue>(U) &&
3417                      Visited.insert(U).second)
3418             Worklist.push_back(U);
3419         }
3420       }
3421     }
3422   }
3423 
3424   if (!BlockAddressUsers.empty()) {
3425     Vals.resize(BlockAddressUsers.size());
3426     for (auto I : llvm::enumerate(BlockAddressUsers))
3427       Vals[I.index()] = VE.getValueID(I.value());
3428     Stream.EmitRecord(bitc::FUNC_CODE_BLOCKADDR_USERS, Vals);
3429     Vals.clear();
3430   }
3431 
3432   // Emit names for all the instructions etc.
3433   if (auto *Symtab = F.getValueSymbolTable())
3434     writeFunctionLevelValueSymbolTable(*Symtab);
3435 
3436   if (NeedsMetadataAttachment)
3437     writeFunctionMetadataAttachment(F);
3438   if (VE.shouldPreserveUseListOrder())
3439     writeUseListBlock(&F);
3440   VE.purgeFunction();
3441   Stream.ExitBlock();
3442 }
3443 
3444 // Emit blockinfo, which defines the standard abbreviations etc.
3445 void ModuleBitcodeWriter::writeBlockInfo() {
3446   // We only want to emit block info records for blocks that have multiple
3447   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
3448   // Other blocks can define their abbrevs inline.
3449   Stream.EnterBlockInfoBlock();
3450 
3451   { // 8-bit fixed-width VST_CODE_ENTRY/VST_CODE_BBENTRY strings.
3452     auto Abbv = std::make_shared<BitCodeAbbrev>();
3453     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
3454     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3455     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3456     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3457     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3458         VST_ENTRY_8_ABBREV)
3459       llvm_unreachable("Unexpected abbrev ordering!");
3460   }
3461 
3462   { // 7-bit fixed width VST_CODE_ENTRY strings.
3463     auto Abbv = std::make_shared<BitCodeAbbrev>();
3464     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3465     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3466     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3467     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3468     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3469         VST_ENTRY_7_ABBREV)
3470       llvm_unreachable("Unexpected abbrev ordering!");
3471   }
3472   { // 6-bit char6 VST_CODE_ENTRY strings.
3473     auto Abbv = std::make_shared<BitCodeAbbrev>();
3474     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3475     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3476     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3477     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3478     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3479         VST_ENTRY_6_ABBREV)
3480       llvm_unreachable("Unexpected abbrev ordering!");
3481   }
3482   { // 6-bit char6 VST_CODE_BBENTRY strings.
3483     auto Abbv = std::make_shared<BitCodeAbbrev>();
3484     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
3485     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3486     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3487     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3488     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3489         VST_BBENTRY_6_ABBREV)
3490       llvm_unreachable("Unexpected abbrev ordering!");
3491   }
3492 
3493   { // SETTYPE abbrev for CONSTANTS_BLOCK.
3494     auto Abbv = std::make_shared<BitCodeAbbrev>();
3495     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
3496     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
3497                               VE.computeBitsRequiredForTypeIndicies()));
3498     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3499         CONSTANTS_SETTYPE_ABBREV)
3500       llvm_unreachable("Unexpected abbrev ordering!");
3501   }
3502 
3503   { // INTEGER abbrev for CONSTANTS_BLOCK.
3504     auto Abbv = std::make_shared<BitCodeAbbrev>();
3505     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
3506     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3507     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3508         CONSTANTS_INTEGER_ABBREV)
3509       llvm_unreachable("Unexpected abbrev ordering!");
3510   }
3511 
3512   { // CE_CAST abbrev for CONSTANTS_BLOCK.
3513     auto Abbv = std::make_shared<BitCodeAbbrev>();
3514     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
3515     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
3516     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
3517                               VE.computeBitsRequiredForTypeIndicies()));
3518     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
3519 
3520     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3521         CONSTANTS_CE_CAST_Abbrev)
3522       llvm_unreachable("Unexpected abbrev ordering!");
3523   }
3524   { // NULL abbrev for CONSTANTS_BLOCK.
3525     auto Abbv = std::make_shared<BitCodeAbbrev>();
3526     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
3527     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3528         CONSTANTS_NULL_Abbrev)
3529       llvm_unreachable("Unexpected abbrev ordering!");
3530   }
3531 
3532   // FIXME: This should only use space for first class types!
3533 
3534   { // INST_LOAD abbrev for FUNCTION_BLOCK.
3535     auto Abbv = std::make_shared<BitCodeAbbrev>();
3536     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
3537     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
3538     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
3539                               VE.computeBitsRequiredForTypeIndicies()));
3540     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
3541     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
3542     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3543         FUNCTION_INST_LOAD_ABBREV)
3544       llvm_unreachable("Unexpected abbrev ordering!");
3545   }
3546   { // INST_UNOP abbrev for FUNCTION_BLOCK.
3547     auto Abbv = std::make_shared<BitCodeAbbrev>();
3548     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3549     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3550     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3551     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3552         FUNCTION_INST_UNOP_ABBREV)
3553       llvm_unreachable("Unexpected abbrev ordering!");
3554   }
3555   { // INST_UNOP_FLAGS abbrev for FUNCTION_BLOCK.
3556     auto Abbv = std::make_shared<BitCodeAbbrev>();
3557     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3558     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3559     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3560     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3561     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3562         FUNCTION_INST_UNOP_FLAGS_ABBREV)
3563       llvm_unreachable("Unexpected abbrev ordering!");
3564   }
3565   { // INST_BINOP abbrev for FUNCTION_BLOCK.
3566     auto Abbv = std::make_shared<BitCodeAbbrev>();
3567     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3568     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3569     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3570     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3571     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3572         FUNCTION_INST_BINOP_ABBREV)
3573       llvm_unreachable("Unexpected abbrev ordering!");
3574   }
3575   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
3576     auto Abbv = std::make_shared<BitCodeAbbrev>();
3577     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3578     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3579     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3580     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3581     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3582     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3583         FUNCTION_INST_BINOP_FLAGS_ABBREV)
3584       llvm_unreachable("Unexpected abbrev ordering!");
3585   }
3586   { // INST_CAST abbrev for FUNCTION_BLOCK.
3587     auto Abbv = std::make_shared<BitCodeAbbrev>();
3588     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
3589     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
3590     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
3591                               VE.computeBitsRequiredForTypeIndicies()));
3592     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
3593     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3594         FUNCTION_INST_CAST_ABBREV)
3595       llvm_unreachable("Unexpected abbrev ordering!");
3596   }
3597 
3598   { // INST_RET abbrev for FUNCTION_BLOCK.
3599     auto Abbv = std::make_shared<BitCodeAbbrev>();
3600     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3601     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3602         FUNCTION_INST_RET_VOID_ABBREV)
3603       llvm_unreachable("Unexpected abbrev ordering!");
3604   }
3605   { // INST_RET abbrev for FUNCTION_BLOCK.
3606     auto Abbv = std::make_shared<BitCodeAbbrev>();
3607     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3608     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
3609     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3610         FUNCTION_INST_RET_VAL_ABBREV)
3611       llvm_unreachable("Unexpected abbrev ordering!");
3612   }
3613   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
3614     auto Abbv = std::make_shared<BitCodeAbbrev>();
3615     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
3616     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3617         FUNCTION_INST_UNREACHABLE_ABBREV)
3618       llvm_unreachable("Unexpected abbrev ordering!");
3619   }
3620   {
3621     auto Abbv = std::make_shared<BitCodeAbbrev>();
3622     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_GEP));
3623     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
3624     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, // dest ty
3625                               Log2_32_Ceil(VE.getTypes().size() + 1)));
3626     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3627     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
3628     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3629         FUNCTION_INST_GEP_ABBREV)
3630       llvm_unreachable("Unexpected abbrev ordering!");
3631   }
3632 
3633   Stream.ExitBlock();
3634 }
3635 
3636 /// Write the module path strings, currently only used when generating
3637 /// a combined index file.
3638 void IndexBitcodeWriter::writeModStrings() {
3639   Stream.EnterSubblock(bitc::MODULE_STRTAB_BLOCK_ID, 3);
3640 
3641   // TODO: See which abbrev sizes we actually need to emit
3642 
3643   // 8-bit fixed-width MST_ENTRY strings.
3644   auto Abbv = std::make_shared<BitCodeAbbrev>();
3645   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3646   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3647   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3648   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3649   unsigned Abbrev8Bit = Stream.EmitAbbrev(std::move(Abbv));
3650 
3651   // 7-bit fixed width MST_ENTRY strings.
3652   Abbv = std::make_shared<BitCodeAbbrev>();
3653   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3654   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3655   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3656   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3657   unsigned Abbrev7Bit = Stream.EmitAbbrev(std::move(Abbv));
3658 
3659   // 6-bit char6 MST_ENTRY strings.
3660   Abbv = std::make_shared<BitCodeAbbrev>();
3661   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3662   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3663   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3664   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3665   unsigned Abbrev6Bit = Stream.EmitAbbrev(std::move(Abbv));
3666 
3667   // Module Hash, 160 bits SHA1. Optionally, emitted after each MST_CODE_ENTRY.
3668   Abbv = std::make_shared<BitCodeAbbrev>();
3669   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_HASH));
3670   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3671   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3672   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3673   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3674   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3675   unsigned AbbrevHash = Stream.EmitAbbrev(std::move(Abbv));
3676 
3677   SmallVector<unsigned, 64> Vals;
3678   forEachModule(
3679       [&](const StringMapEntry<std::pair<uint64_t, ModuleHash>> &MPSE) {
3680         StringRef Key = MPSE.getKey();
3681         const auto &Value = MPSE.getValue();
3682         StringEncoding Bits = getStringEncoding(Key);
3683         unsigned AbbrevToUse = Abbrev8Bit;
3684         if (Bits == SE_Char6)
3685           AbbrevToUse = Abbrev6Bit;
3686         else if (Bits == SE_Fixed7)
3687           AbbrevToUse = Abbrev7Bit;
3688 
3689         Vals.push_back(Value.first);
3690         Vals.append(Key.begin(), Key.end());
3691 
3692         // Emit the finished record.
3693         Stream.EmitRecord(bitc::MST_CODE_ENTRY, Vals, AbbrevToUse);
3694 
3695         // Emit an optional hash for the module now
3696         const auto &Hash = Value.second;
3697         if (llvm::any_of(Hash, [](uint32_t H) { return H; })) {
3698           Vals.assign(Hash.begin(), Hash.end());
3699           // Emit the hash record.
3700           Stream.EmitRecord(bitc::MST_CODE_HASH, Vals, AbbrevHash);
3701         }
3702 
3703         Vals.clear();
3704       });
3705   Stream.ExitBlock();
3706 }
3707 
3708 /// Write the function type metadata related records that need to appear before
3709 /// a function summary entry (whether per-module or combined).
3710 template <typename Fn>
3711 static void writeFunctionTypeMetadataRecords(BitstreamWriter &Stream,
3712                                              FunctionSummary *FS,
3713                                              Fn GetValueID) {
3714   if (!FS->type_tests().empty())
3715     Stream.EmitRecord(bitc::FS_TYPE_TESTS, FS->type_tests());
3716 
3717   SmallVector<uint64_t, 64> Record;
3718 
3719   auto WriteVFuncIdVec = [&](uint64_t Ty,
3720                              ArrayRef<FunctionSummary::VFuncId> VFs) {
3721     if (VFs.empty())
3722       return;
3723     Record.clear();
3724     for (auto &VF : VFs) {
3725       Record.push_back(VF.GUID);
3726       Record.push_back(VF.Offset);
3727     }
3728     Stream.EmitRecord(Ty, Record);
3729   };
3730 
3731   WriteVFuncIdVec(bitc::FS_TYPE_TEST_ASSUME_VCALLS,
3732                   FS->type_test_assume_vcalls());
3733   WriteVFuncIdVec(bitc::FS_TYPE_CHECKED_LOAD_VCALLS,
3734                   FS->type_checked_load_vcalls());
3735 
3736   auto WriteConstVCallVec = [&](uint64_t Ty,
3737                                 ArrayRef<FunctionSummary::ConstVCall> VCs) {
3738     for (auto &VC : VCs) {
3739       Record.clear();
3740       Record.push_back(VC.VFunc.GUID);
3741       Record.push_back(VC.VFunc.Offset);
3742       llvm::append_range(Record, VC.Args);
3743       Stream.EmitRecord(Ty, Record);
3744     }
3745   };
3746 
3747   WriteConstVCallVec(bitc::FS_TYPE_TEST_ASSUME_CONST_VCALL,
3748                      FS->type_test_assume_const_vcalls());
3749   WriteConstVCallVec(bitc::FS_TYPE_CHECKED_LOAD_CONST_VCALL,
3750                      FS->type_checked_load_const_vcalls());
3751 
3752   auto WriteRange = [&](ConstantRange Range) {
3753     Range = Range.sextOrTrunc(FunctionSummary::ParamAccess::RangeWidth);
3754     assert(Range.getLower().getNumWords() == 1);
3755     assert(Range.getUpper().getNumWords() == 1);
3756     emitSignedInt64(Record, *Range.getLower().getRawData());
3757     emitSignedInt64(Record, *Range.getUpper().getRawData());
3758   };
3759 
3760   if (!FS->paramAccesses().empty()) {
3761     Record.clear();
3762     for (auto &Arg : FS->paramAccesses()) {
3763       size_t UndoSize = Record.size();
3764       Record.push_back(Arg.ParamNo);
3765       WriteRange(Arg.Use);
3766       Record.push_back(Arg.Calls.size());
3767       for (auto &Call : Arg.Calls) {
3768         Record.push_back(Call.ParamNo);
3769         Optional<unsigned> ValueID = GetValueID(Call.Callee);
3770         if (!ValueID) {
3771           // If ValueID is unknown we can't drop just this call, we must drop
3772           // entire parameter.
3773           Record.resize(UndoSize);
3774           break;
3775         }
3776         Record.push_back(*ValueID);
3777         WriteRange(Call.Offsets);
3778       }
3779     }
3780     if (!Record.empty())
3781       Stream.EmitRecord(bitc::FS_PARAM_ACCESS, Record);
3782   }
3783 }
3784 
3785 /// Collect type IDs from type tests used by function.
3786 static void
3787 getReferencedTypeIds(FunctionSummary *FS,
3788                      std::set<GlobalValue::GUID> &ReferencedTypeIds) {
3789   if (!FS->type_tests().empty())
3790     for (auto &TT : FS->type_tests())
3791       ReferencedTypeIds.insert(TT);
3792 
3793   auto GetReferencedTypesFromVFuncIdVec =
3794       [&](ArrayRef<FunctionSummary::VFuncId> VFs) {
3795         for (auto &VF : VFs)
3796           ReferencedTypeIds.insert(VF.GUID);
3797       };
3798 
3799   GetReferencedTypesFromVFuncIdVec(FS->type_test_assume_vcalls());
3800   GetReferencedTypesFromVFuncIdVec(FS->type_checked_load_vcalls());
3801 
3802   auto GetReferencedTypesFromConstVCallVec =
3803       [&](ArrayRef<FunctionSummary::ConstVCall> VCs) {
3804         for (auto &VC : VCs)
3805           ReferencedTypeIds.insert(VC.VFunc.GUID);
3806       };
3807 
3808   GetReferencedTypesFromConstVCallVec(FS->type_test_assume_const_vcalls());
3809   GetReferencedTypesFromConstVCallVec(FS->type_checked_load_const_vcalls());
3810 }
3811 
3812 static void writeWholeProgramDevirtResolutionByArg(
3813     SmallVector<uint64_t, 64> &NameVals, const std::vector<uint64_t> &args,
3814     const WholeProgramDevirtResolution::ByArg &ByArg) {
3815   NameVals.push_back(args.size());
3816   llvm::append_range(NameVals, args);
3817 
3818   NameVals.push_back(ByArg.TheKind);
3819   NameVals.push_back(ByArg.Info);
3820   NameVals.push_back(ByArg.Byte);
3821   NameVals.push_back(ByArg.Bit);
3822 }
3823 
3824 static void writeWholeProgramDevirtResolution(
3825     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3826     uint64_t Id, const WholeProgramDevirtResolution &Wpd) {
3827   NameVals.push_back(Id);
3828 
3829   NameVals.push_back(Wpd.TheKind);
3830   NameVals.push_back(StrtabBuilder.add(Wpd.SingleImplName));
3831   NameVals.push_back(Wpd.SingleImplName.size());
3832 
3833   NameVals.push_back(Wpd.ResByArg.size());
3834   for (auto &A : Wpd.ResByArg)
3835     writeWholeProgramDevirtResolutionByArg(NameVals, A.first, A.second);
3836 }
3837 
3838 static void writeTypeIdSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
3839                                      StringTableBuilder &StrtabBuilder,
3840                                      const std::string &Id,
3841                                      const TypeIdSummary &Summary) {
3842   NameVals.push_back(StrtabBuilder.add(Id));
3843   NameVals.push_back(Id.size());
3844 
3845   NameVals.push_back(Summary.TTRes.TheKind);
3846   NameVals.push_back(Summary.TTRes.SizeM1BitWidth);
3847   NameVals.push_back(Summary.TTRes.AlignLog2);
3848   NameVals.push_back(Summary.TTRes.SizeM1);
3849   NameVals.push_back(Summary.TTRes.BitMask);
3850   NameVals.push_back(Summary.TTRes.InlineBits);
3851 
3852   for (auto &W : Summary.WPDRes)
3853     writeWholeProgramDevirtResolution(NameVals, StrtabBuilder, W.first,
3854                                       W.second);
3855 }
3856 
3857 static void writeTypeIdCompatibleVtableSummaryRecord(
3858     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3859     const std::string &Id, const TypeIdCompatibleVtableInfo &Summary,
3860     ValueEnumerator &VE) {
3861   NameVals.push_back(StrtabBuilder.add(Id));
3862   NameVals.push_back(Id.size());
3863 
3864   for (auto &P : Summary) {
3865     NameVals.push_back(P.AddressPointOffset);
3866     NameVals.push_back(VE.getValueID(P.VTableVI.getValue()));
3867   }
3868 }
3869 
3870 // Helper to emit a single function summary record.
3871 void ModuleBitcodeWriterBase::writePerModuleFunctionSummaryRecord(
3872     SmallVector<uint64_t, 64> &NameVals, GlobalValueSummary *Summary,
3873     unsigned ValueID, unsigned FSCallsAbbrev, unsigned FSCallsProfileAbbrev,
3874     const Function &F) {
3875   NameVals.push_back(ValueID);
3876 
3877   FunctionSummary *FS = cast<FunctionSummary>(Summary);
3878 
3879   writeFunctionTypeMetadataRecords(
3880       Stream, FS, [&](const ValueInfo &VI) -> Optional<unsigned> {
3881         return {VE.getValueID(VI.getValue())};
3882       });
3883 
3884   auto SpecialRefCnts = FS->specialRefCounts();
3885   NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
3886   NameVals.push_back(FS->instCount());
3887   NameVals.push_back(getEncodedFFlags(FS->fflags()));
3888   NameVals.push_back(FS->refs().size());
3889   NameVals.push_back(SpecialRefCnts.first);  // rorefcnt
3890   NameVals.push_back(SpecialRefCnts.second); // worefcnt
3891 
3892   for (auto &RI : FS->refs())
3893     NameVals.push_back(VE.getValueID(RI.getValue()));
3894 
3895   bool HasProfileData =
3896       F.hasProfileData() || ForceSummaryEdgesCold != FunctionSummary::FSHT_None;
3897   for (auto &ECI : FS->calls()) {
3898     NameVals.push_back(getValueId(ECI.first));
3899     if (HasProfileData)
3900       NameVals.push_back(static_cast<uint8_t>(ECI.second.Hotness));
3901     else if (WriteRelBFToSummary)
3902       NameVals.push_back(ECI.second.RelBlockFreq);
3903   }
3904 
3905   unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
3906   unsigned Code =
3907       (HasProfileData ? bitc::FS_PERMODULE_PROFILE
3908                       : (WriteRelBFToSummary ? bitc::FS_PERMODULE_RELBF
3909                                              : bitc::FS_PERMODULE));
3910 
3911   // Emit the finished record.
3912   Stream.EmitRecord(Code, NameVals, FSAbbrev);
3913   NameVals.clear();
3914 }
3915 
3916 // Collect the global value references in the given variable's initializer,
3917 // and emit them in a summary record.
3918 void ModuleBitcodeWriterBase::writeModuleLevelReferences(
3919     const GlobalVariable &V, SmallVector<uint64_t, 64> &NameVals,
3920     unsigned FSModRefsAbbrev, unsigned FSModVTableRefsAbbrev) {
3921   auto VI = Index->getValueInfo(V.getGUID());
3922   if (!VI || VI.getSummaryList().empty()) {
3923     // Only declarations should not have a summary (a declaration might however
3924     // have a summary if the def was in module level asm).
3925     assert(V.isDeclaration());
3926     return;
3927   }
3928   auto *Summary = VI.getSummaryList()[0].get();
3929   NameVals.push_back(VE.getValueID(&V));
3930   GlobalVarSummary *VS = cast<GlobalVarSummary>(Summary);
3931   NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
3932   NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
3933 
3934   auto VTableFuncs = VS->vTableFuncs();
3935   if (!VTableFuncs.empty())
3936     NameVals.push_back(VS->refs().size());
3937 
3938   unsigned SizeBeforeRefs = NameVals.size();
3939   for (auto &RI : VS->refs())
3940     NameVals.push_back(VE.getValueID(RI.getValue()));
3941   // Sort the refs for determinism output, the vector returned by FS->refs() has
3942   // been initialized from a DenseSet.
3943   llvm::sort(drop_begin(NameVals, SizeBeforeRefs));
3944 
3945   if (VTableFuncs.empty())
3946     Stream.EmitRecord(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS, NameVals,
3947                       FSModRefsAbbrev);
3948   else {
3949     // VTableFuncs pairs should already be sorted by offset.
3950     for (auto &P : VTableFuncs) {
3951       NameVals.push_back(VE.getValueID(P.FuncVI.getValue()));
3952       NameVals.push_back(P.VTableOffset);
3953     }
3954 
3955     Stream.EmitRecord(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS, NameVals,
3956                       FSModVTableRefsAbbrev);
3957   }
3958   NameVals.clear();
3959 }
3960 
3961 /// Emit the per-module summary section alongside the rest of
3962 /// the module's bitcode.
3963 void ModuleBitcodeWriterBase::writePerModuleGlobalValueSummary() {
3964   // By default we compile with ThinLTO if the module has a summary, but the
3965   // client can request full LTO with a module flag.
3966   bool IsThinLTO = true;
3967   if (auto *MD =
3968           mdconst::extract_or_null<ConstantInt>(M.getModuleFlag("ThinLTO")))
3969     IsThinLTO = MD->getZExtValue();
3970   Stream.EnterSubblock(IsThinLTO ? bitc::GLOBALVAL_SUMMARY_BLOCK_ID
3971                                  : bitc::FULL_LTO_GLOBALVAL_SUMMARY_BLOCK_ID,
3972                        4);
3973 
3974   Stream.EmitRecord(
3975       bitc::FS_VERSION,
3976       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
3977 
3978   // Write the index flags.
3979   uint64_t Flags = 0;
3980   // Bits 1-3 are set only in the combined index, skip them.
3981   if (Index->enableSplitLTOUnit())
3982     Flags |= 0x8;
3983   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Flags});
3984 
3985   if (Index->begin() == Index->end()) {
3986     Stream.ExitBlock();
3987     return;
3988   }
3989 
3990   for (const auto &GVI : valueIds()) {
3991     Stream.EmitRecord(bitc::FS_VALUE_GUID,
3992                       ArrayRef<uint64_t>{GVI.second, GVI.first});
3993   }
3994 
3995   // Abbrev for FS_PERMODULE_PROFILE.
3996   auto Abbv = std::make_shared<BitCodeAbbrev>();
3997   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_PROFILE));
3998   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3999   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4000   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4001   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4002   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4003   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4004   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4005   // numrefs x valueid, n x (valueid, hotness)
4006   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4007   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4008   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4009 
4010   // Abbrev for FS_PERMODULE or FS_PERMODULE_RELBF.
4011   Abbv = std::make_shared<BitCodeAbbrev>();
4012   if (WriteRelBFToSummary)
4013     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_RELBF));
4014   else
4015     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE));
4016   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4017   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4018   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4019   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4020   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4021   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4022   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4023   // numrefs x valueid, n x (valueid [, rel_block_freq])
4024   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4025   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4026   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4027 
4028   // Abbrev for FS_PERMODULE_GLOBALVAR_INIT_REFS.
4029   Abbv = std::make_shared<BitCodeAbbrev>();
4030   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS));
4031   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
4032   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
4033   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));  // valueids
4034   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4035   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4036 
4037   // Abbrev for FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS.
4038   Abbv = std::make_shared<BitCodeAbbrev>();
4039   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS));
4040   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
4041   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
4042   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numrefs
4043   // numrefs x valueid, n x (valueid , offset)
4044   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4045   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4046   unsigned FSModVTableRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4047 
4048   // Abbrev for FS_ALIAS.
4049   Abbv = std::make_shared<BitCodeAbbrev>();
4050   Abbv->Add(BitCodeAbbrevOp(bitc::FS_ALIAS));
4051   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4052   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4053   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4054   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4055 
4056   // Abbrev for FS_TYPE_ID_METADATA
4057   Abbv = std::make_shared<BitCodeAbbrev>();
4058   Abbv->Add(BitCodeAbbrevOp(bitc::FS_TYPE_ID_METADATA));
4059   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid strtab index
4060   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid length
4061   // n x (valueid , offset)
4062   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4063   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4064   unsigned TypeIdCompatibleVtableAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4065 
4066   SmallVector<uint64_t, 64> NameVals;
4067   // Iterate over the list of functions instead of the Index to
4068   // ensure the ordering is stable.
4069   for (const Function &F : M) {
4070     // Summary emission does not support anonymous functions, they have to
4071     // renamed using the anonymous function renaming pass.
4072     if (!F.hasName())
4073       report_fatal_error("Unexpected anonymous function when writing summary");
4074 
4075     ValueInfo VI = Index->getValueInfo(F.getGUID());
4076     if (!VI || VI.getSummaryList().empty()) {
4077       // Only declarations should not have a summary (a declaration might
4078       // however have a summary if the def was in module level asm).
4079       assert(F.isDeclaration());
4080       continue;
4081     }
4082     auto *Summary = VI.getSummaryList()[0].get();
4083     writePerModuleFunctionSummaryRecord(NameVals, Summary, VE.getValueID(&F),
4084                                         FSCallsAbbrev, FSCallsProfileAbbrev, F);
4085   }
4086 
4087   // Capture references from GlobalVariable initializers, which are outside
4088   // of a function scope.
4089   for (const GlobalVariable &G : M.globals())
4090     writeModuleLevelReferences(G, NameVals, FSModRefsAbbrev,
4091                                FSModVTableRefsAbbrev);
4092 
4093   for (const GlobalAlias &A : M.aliases()) {
4094     auto *Aliasee = A.getAliaseeObject();
4095     if (!Aliasee->hasName())
4096       // Nameless function don't have an entry in the summary, skip it.
4097       continue;
4098     auto AliasId = VE.getValueID(&A);
4099     auto AliaseeId = VE.getValueID(Aliasee);
4100     NameVals.push_back(AliasId);
4101     auto *Summary = Index->getGlobalValueSummary(A);
4102     AliasSummary *AS = cast<AliasSummary>(Summary);
4103     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
4104     NameVals.push_back(AliaseeId);
4105     Stream.EmitRecord(bitc::FS_ALIAS, NameVals, FSAliasAbbrev);
4106     NameVals.clear();
4107   }
4108 
4109   for (auto &S : Index->typeIdCompatibleVtableMap()) {
4110     writeTypeIdCompatibleVtableSummaryRecord(NameVals, StrtabBuilder, S.first,
4111                                              S.second, VE);
4112     Stream.EmitRecord(bitc::FS_TYPE_ID_METADATA, NameVals,
4113                       TypeIdCompatibleVtableAbbrev);
4114     NameVals.clear();
4115   }
4116 
4117   Stream.EmitRecord(bitc::FS_BLOCK_COUNT,
4118                     ArrayRef<uint64_t>{Index->getBlockCount()});
4119 
4120   Stream.ExitBlock();
4121 }
4122 
4123 /// Emit the combined summary section into the combined index file.
4124 void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
4125   Stream.EnterSubblock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID, 3);
4126   Stream.EmitRecord(
4127       bitc::FS_VERSION,
4128       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
4129 
4130   // Write the index flags.
4131   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Index.getFlags()});
4132 
4133   for (const auto &GVI : valueIds()) {
4134     Stream.EmitRecord(bitc::FS_VALUE_GUID,
4135                       ArrayRef<uint64_t>{GVI.second, GVI.first});
4136   }
4137 
4138   // Abbrev for FS_COMBINED.
4139   auto Abbv = std::make_shared<BitCodeAbbrev>();
4140   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED));
4141   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4142   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4143   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4144   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4145   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4146   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
4147   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4148   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4149   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4150   // numrefs x valueid, n x (valueid)
4151   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4152   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4153   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4154 
4155   // Abbrev for FS_COMBINED_PROFILE.
4156   Abbv = std::make_shared<BitCodeAbbrev>();
4157   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_PROFILE));
4158   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4159   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4160   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4161   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4162   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4163   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
4164   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4165   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4166   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4167   // numrefs x valueid, n x (valueid, hotness)
4168   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4169   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4170   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4171 
4172   // Abbrev for FS_COMBINED_GLOBALVAR_INIT_REFS.
4173   Abbv = std::make_shared<BitCodeAbbrev>();
4174   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS));
4175   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4176   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4177   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4178   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));    // valueids
4179   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4180   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4181 
4182   // Abbrev for FS_COMBINED_ALIAS.
4183   Abbv = std::make_shared<BitCodeAbbrev>();
4184   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_ALIAS));
4185   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4186   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4187   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4188   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4189   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4190 
4191   // The aliases are emitted as a post-pass, and will point to the value
4192   // id of the aliasee. Save them in a vector for post-processing.
4193   SmallVector<AliasSummary *, 64> Aliases;
4194 
4195   // Save the value id for each summary for alias emission.
4196   DenseMap<const GlobalValueSummary *, unsigned> SummaryToValueIdMap;
4197 
4198   SmallVector<uint64_t, 64> NameVals;
4199 
4200   // Set that will be populated during call to writeFunctionTypeMetadataRecords
4201   // with the type ids referenced by this index file.
4202   std::set<GlobalValue::GUID> ReferencedTypeIds;
4203 
4204   // For local linkage, we also emit the original name separately
4205   // immediately after the record.
4206   auto MaybeEmitOriginalName = [&](GlobalValueSummary &S) {
4207     // We don't need to emit the original name if we are writing the index for
4208     // distributed backends (in which case ModuleToSummariesForIndex is
4209     // non-null). The original name is only needed during the thin link, since
4210     // for SamplePGO the indirect call targets for local functions have
4211     // have the original name annotated in profile.
4212     // Continue to emit it when writing out the entire combined index, which is
4213     // used in testing the thin link via llvm-lto.
4214     if (ModuleToSummariesForIndex || !GlobalValue::isLocalLinkage(S.linkage()))
4215       return;
4216     NameVals.push_back(S.getOriginalName());
4217     Stream.EmitRecord(bitc::FS_COMBINED_ORIGINAL_NAME, NameVals);
4218     NameVals.clear();
4219   };
4220 
4221   std::set<GlobalValue::GUID> DefOrUseGUIDs;
4222   forEachSummary([&](GVInfo I, bool IsAliasee) {
4223     GlobalValueSummary *S = I.second;
4224     assert(S);
4225     DefOrUseGUIDs.insert(I.first);
4226     for (const ValueInfo &VI : S->refs())
4227       DefOrUseGUIDs.insert(VI.getGUID());
4228 
4229     auto ValueId = getValueId(I.first);
4230     assert(ValueId);
4231     SummaryToValueIdMap[S] = *ValueId;
4232 
4233     // If this is invoked for an aliasee, we want to record the above
4234     // mapping, but then not emit a summary entry (if the aliasee is
4235     // to be imported, we will invoke this separately with IsAliasee=false).
4236     if (IsAliasee)
4237       return;
4238 
4239     if (auto *AS = dyn_cast<AliasSummary>(S)) {
4240       // Will process aliases as a post-pass because the reader wants all
4241       // global to be loaded first.
4242       Aliases.push_back(AS);
4243       return;
4244     }
4245 
4246     if (auto *VS = dyn_cast<GlobalVarSummary>(S)) {
4247       NameVals.push_back(*ValueId);
4248       NameVals.push_back(Index.getModuleId(VS->modulePath()));
4249       NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
4250       NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
4251       for (auto &RI : VS->refs()) {
4252         auto RefValueId = getValueId(RI.getGUID());
4253         if (!RefValueId)
4254           continue;
4255         NameVals.push_back(*RefValueId);
4256       }
4257 
4258       // Emit the finished record.
4259       Stream.EmitRecord(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS, NameVals,
4260                         FSModRefsAbbrev);
4261       NameVals.clear();
4262       MaybeEmitOriginalName(*S);
4263       return;
4264     }
4265 
4266     auto GetValueId = [&](const ValueInfo &VI) -> Optional<unsigned> {
4267       return getValueId(VI.getGUID());
4268     };
4269 
4270     auto *FS = cast<FunctionSummary>(S);
4271     writeFunctionTypeMetadataRecords(Stream, FS, GetValueId);
4272     getReferencedTypeIds(FS, ReferencedTypeIds);
4273 
4274     NameVals.push_back(*ValueId);
4275     NameVals.push_back(Index.getModuleId(FS->modulePath()));
4276     NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
4277     NameVals.push_back(FS->instCount());
4278     NameVals.push_back(getEncodedFFlags(FS->fflags()));
4279     NameVals.push_back(FS->entryCount());
4280 
4281     // Fill in below
4282     NameVals.push_back(0); // numrefs
4283     NameVals.push_back(0); // rorefcnt
4284     NameVals.push_back(0); // worefcnt
4285 
4286     unsigned Count = 0, RORefCnt = 0, WORefCnt = 0;
4287     for (auto &RI : FS->refs()) {
4288       auto RefValueId = getValueId(RI.getGUID());
4289       if (!RefValueId)
4290         continue;
4291       NameVals.push_back(*RefValueId);
4292       if (RI.isReadOnly())
4293         RORefCnt++;
4294       else if (RI.isWriteOnly())
4295         WORefCnt++;
4296       Count++;
4297     }
4298     NameVals[6] = Count;
4299     NameVals[7] = RORefCnt;
4300     NameVals[8] = WORefCnt;
4301 
4302     bool HasProfileData = false;
4303     for (auto &EI : FS->calls()) {
4304       HasProfileData |=
4305           EI.second.getHotness() != CalleeInfo::HotnessType::Unknown;
4306       if (HasProfileData)
4307         break;
4308     }
4309 
4310     for (auto &EI : FS->calls()) {
4311       // If this GUID doesn't have a value id, it doesn't have a function
4312       // summary and we don't need to record any calls to it.
4313       Optional<unsigned> CallValueId = GetValueId(EI.first);
4314       if (!CallValueId)
4315         continue;
4316       NameVals.push_back(*CallValueId);
4317       if (HasProfileData)
4318         NameVals.push_back(static_cast<uint8_t>(EI.second.Hotness));
4319     }
4320 
4321     unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
4322     unsigned Code =
4323         (HasProfileData ? bitc::FS_COMBINED_PROFILE : bitc::FS_COMBINED);
4324 
4325     // Emit the finished record.
4326     Stream.EmitRecord(Code, NameVals, FSAbbrev);
4327     NameVals.clear();
4328     MaybeEmitOriginalName(*S);
4329   });
4330 
4331   for (auto *AS : Aliases) {
4332     auto AliasValueId = SummaryToValueIdMap[AS];
4333     assert(AliasValueId);
4334     NameVals.push_back(AliasValueId);
4335     NameVals.push_back(Index.getModuleId(AS->modulePath()));
4336     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
4337     auto AliaseeValueId = SummaryToValueIdMap[&AS->getAliasee()];
4338     assert(AliaseeValueId);
4339     NameVals.push_back(AliaseeValueId);
4340 
4341     // Emit the finished record.
4342     Stream.EmitRecord(bitc::FS_COMBINED_ALIAS, NameVals, FSAliasAbbrev);
4343     NameVals.clear();
4344     MaybeEmitOriginalName(*AS);
4345 
4346     if (auto *FS = dyn_cast<FunctionSummary>(&AS->getAliasee()))
4347       getReferencedTypeIds(FS, ReferencedTypeIds);
4348   }
4349 
4350   if (!Index.cfiFunctionDefs().empty()) {
4351     for (auto &S : Index.cfiFunctionDefs()) {
4352       if (DefOrUseGUIDs.count(
4353               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4354         NameVals.push_back(StrtabBuilder.add(S));
4355         NameVals.push_back(S.size());
4356       }
4357     }
4358     if (!NameVals.empty()) {
4359       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DEFS, NameVals);
4360       NameVals.clear();
4361     }
4362   }
4363 
4364   if (!Index.cfiFunctionDecls().empty()) {
4365     for (auto &S : Index.cfiFunctionDecls()) {
4366       if (DefOrUseGUIDs.count(
4367               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4368         NameVals.push_back(StrtabBuilder.add(S));
4369         NameVals.push_back(S.size());
4370       }
4371     }
4372     if (!NameVals.empty()) {
4373       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DECLS, NameVals);
4374       NameVals.clear();
4375     }
4376   }
4377 
4378   // Walk the GUIDs that were referenced, and write the
4379   // corresponding type id records.
4380   for (auto &T : ReferencedTypeIds) {
4381     auto TidIter = Index.typeIds().equal_range(T);
4382     for (auto It = TidIter.first; It != TidIter.second; ++It) {
4383       writeTypeIdSummaryRecord(NameVals, StrtabBuilder, It->second.first,
4384                                It->second.second);
4385       Stream.EmitRecord(bitc::FS_TYPE_ID, NameVals);
4386       NameVals.clear();
4387     }
4388   }
4389 
4390   Stream.EmitRecord(bitc::FS_BLOCK_COUNT,
4391                     ArrayRef<uint64_t>{Index.getBlockCount()});
4392 
4393   Stream.ExitBlock();
4394 }
4395 
4396 /// Create the "IDENTIFICATION_BLOCK_ID" containing a single string with the
4397 /// current llvm version, and a record for the epoch number.
4398 static void writeIdentificationBlock(BitstreamWriter &Stream) {
4399   Stream.EnterSubblock(bitc::IDENTIFICATION_BLOCK_ID, 5);
4400 
4401   // Write the "user readable" string identifying the bitcode producer
4402   auto Abbv = std::make_shared<BitCodeAbbrev>();
4403   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_STRING));
4404   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4405   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
4406   auto StringAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4407   writeStringRecord(Stream, bitc::IDENTIFICATION_CODE_STRING,
4408                     "LLVM" LLVM_VERSION_STRING, StringAbbrev);
4409 
4410   // Write the epoch version
4411   Abbv = std::make_shared<BitCodeAbbrev>();
4412   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_EPOCH));
4413   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
4414   auto EpochAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4415   constexpr std::array<unsigned, 1> Vals = {{bitc::BITCODE_CURRENT_EPOCH}};
4416   Stream.EmitRecord(bitc::IDENTIFICATION_CODE_EPOCH, Vals, EpochAbbrev);
4417   Stream.ExitBlock();
4418 }
4419 
4420 void ModuleBitcodeWriter::writeModuleHash(size_t BlockStartPos) {
4421   // Emit the module's hash.
4422   // MODULE_CODE_HASH: [5*i32]
4423   if (GenerateHash) {
4424     uint32_t Vals[5];
4425     Hasher.update(ArrayRef<uint8_t>((const uint8_t *)&(Buffer)[BlockStartPos],
4426                                     Buffer.size() - BlockStartPos));
4427     std::array<uint8_t, 20> Hash = Hasher.result();
4428     for (int Pos = 0; Pos < 20; Pos += 4) {
4429       Vals[Pos / 4] = support::endian::read32be(Hash.data() + Pos);
4430     }
4431 
4432     // Emit the finished record.
4433     Stream.EmitRecord(bitc::MODULE_CODE_HASH, Vals);
4434 
4435     if (ModHash)
4436       // Save the written hash value.
4437       llvm::copy(Vals, std::begin(*ModHash));
4438   }
4439 }
4440 
4441 void ModuleBitcodeWriter::write() {
4442   writeIdentificationBlock(Stream);
4443 
4444   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4445   size_t BlockStartPos = Buffer.size();
4446 
4447   writeModuleVersion();
4448 
4449   // Emit blockinfo, which defines the standard abbreviations etc.
4450   writeBlockInfo();
4451 
4452   // Emit information describing all of the types in the module.
4453   writeTypeTable();
4454 
4455   // Emit information about attribute groups.
4456   writeAttributeGroupTable();
4457 
4458   // Emit information about parameter attributes.
4459   writeAttributeTable();
4460 
4461   writeComdats();
4462 
4463   // Emit top-level description of module, including target triple, inline asm,
4464   // descriptors for global variables, and function prototype info.
4465   writeModuleInfo();
4466 
4467   // Emit constants.
4468   writeModuleConstants();
4469 
4470   // Emit metadata kind names.
4471   writeModuleMetadataKinds();
4472 
4473   // Emit metadata.
4474   writeModuleMetadata();
4475 
4476   // Emit module-level use-lists.
4477   if (VE.shouldPreserveUseListOrder())
4478     writeUseListBlock(nullptr);
4479 
4480   writeOperandBundleTags();
4481   writeSyncScopeNames();
4482 
4483   // Emit function bodies.
4484   DenseMap<const Function *, uint64_t> FunctionToBitcodeIndex;
4485   for (const Function &F : M)
4486     if (!F.isDeclaration())
4487       writeFunction(F, FunctionToBitcodeIndex);
4488 
4489   // Need to write after the above call to WriteFunction which populates
4490   // the summary information in the index.
4491   if (Index)
4492     writePerModuleGlobalValueSummary();
4493 
4494   writeGlobalValueSymbolTable(FunctionToBitcodeIndex);
4495 
4496   writeModuleHash(BlockStartPos);
4497 
4498   Stream.ExitBlock();
4499 }
4500 
4501 static void writeInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
4502                                uint32_t &Position) {
4503   support::endian::write32le(&Buffer[Position], Value);
4504   Position += 4;
4505 }
4506 
4507 /// If generating a bc file on darwin, we have to emit a
4508 /// header and trailer to make it compatible with the system archiver.  To do
4509 /// this we emit the following header, and then emit a trailer that pads the
4510 /// file out to be a multiple of 16 bytes.
4511 ///
4512 /// struct bc_header {
4513 ///   uint32_t Magic;         // 0x0B17C0DE
4514 ///   uint32_t Version;       // Version, currently always 0.
4515 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
4516 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
4517 ///   uint32_t CPUType;       // CPU specifier.
4518 ///   ... potentially more later ...
4519 /// };
4520 static void emitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
4521                                          const Triple &TT) {
4522   unsigned CPUType = ~0U;
4523 
4524   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
4525   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
4526   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
4527   // specific constants here because they are implicitly part of the Darwin ABI.
4528   enum {
4529     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
4530     DARWIN_CPU_TYPE_X86        = 7,
4531     DARWIN_CPU_TYPE_ARM        = 12,
4532     DARWIN_CPU_TYPE_POWERPC    = 18
4533   };
4534 
4535   Triple::ArchType Arch = TT.getArch();
4536   if (Arch == Triple::x86_64)
4537     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
4538   else if (Arch == Triple::x86)
4539     CPUType = DARWIN_CPU_TYPE_X86;
4540   else if (Arch == Triple::ppc)
4541     CPUType = DARWIN_CPU_TYPE_POWERPC;
4542   else if (Arch == Triple::ppc64)
4543     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
4544   else if (Arch == Triple::arm || Arch == Triple::thumb)
4545     CPUType = DARWIN_CPU_TYPE_ARM;
4546 
4547   // Traditional Bitcode starts after header.
4548   assert(Buffer.size() >= BWH_HeaderSize &&
4549          "Expected header size to be reserved");
4550   unsigned BCOffset = BWH_HeaderSize;
4551   unsigned BCSize = Buffer.size() - BWH_HeaderSize;
4552 
4553   // Write the magic and version.
4554   unsigned Position = 0;
4555   writeInt32ToBuffer(0x0B17C0DE, Buffer, Position);
4556   writeInt32ToBuffer(0, Buffer, Position); // Version.
4557   writeInt32ToBuffer(BCOffset, Buffer, Position);
4558   writeInt32ToBuffer(BCSize, Buffer, Position);
4559   writeInt32ToBuffer(CPUType, Buffer, Position);
4560 
4561   // If the file is not a multiple of 16 bytes, insert dummy padding.
4562   while (Buffer.size() & 15)
4563     Buffer.push_back(0);
4564 }
4565 
4566 /// Helper to write the header common to all bitcode files.
4567 static void writeBitcodeHeader(BitstreamWriter &Stream) {
4568   // Emit the file header.
4569   Stream.Emit((unsigned)'B', 8);
4570   Stream.Emit((unsigned)'C', 8);
4571   Stream.Emit(0x0, 4);
4572   Stream.Emit(0xC, 4);
4573   Stream.Emit(0xE, 4);
4574   Stream.Emit(0xD, 4);
4575 }
4576 
4577 BitcodeWriter::BitcodeWriter(SmallVectorImpl<char> &Buffer, raw_fd_stream *FS)
4578     : Buffer(Buffer), Stream(new BitstreamWriter(Buffer, FS, FlushThreshold)) {
4579   writeBitcodeHeader(*Stream);
4580 }
4581 
4582 BitcodeWriter::~BitcodeWriter() { assert(WroteStrtab); }
4583 
4584 void BitcodeWriter::writeBlob(unsigned Block, unsigned Record, StringRef Blob) {
4585   Stream->EnterSubblock(Block, 3);
4586 
4587   auto Abbv = std::make_shared<BitCodeAbbrev>();
4588   Abbv->Add(BitCodeAbbrevOp(Record));
4589   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
4590   auto AbbrevNo = Stream->EmitAbbrev(std::move(Abbv));
4591 
4592   Stream->EmitRecordWithBlob(AbbrevNo, ArrayRef<uint64_t>{Record}, Blob);
4593 
4594   Stream->ExitBlock();
4595 }
4596 
4597 void BitcodeWriter::writeSymtab() {
4598   assert(!WroteStrtab && !WroteSymtab);
4599 
4600   // If any module has module-level inline asm, we will require a registered asm
4601   // parser for the target so that we can create an accurate symbol table for
4602   // the module.
4603   for (Module *M : Mods) {
4604     if (M->getModuleInlineAsm().empty())
4605       continue;
4606 
4607     std::string Err;
4608     const Triple TT(M->getTargetTriple());
4609     const Target *T = TargetRegistry::lookupTarget(TT.str(), Err);
4610     if (!T || !T->hasMCAsmParser())
4611       return;
4612   }
4613 
4614   WroteSymtab = true;
4615   SmallVector<char, 0> Symtab;
4616   // The irsymtab::build function may be unable to create a symbol table if the
4617   // module is malformed (e.g. it contains an invalid alias). Writing a symbol
4618   // table is not required for correctness, but we still want to be able to
4619   // write malformed modules to bitcode files, so swallow the error.
4620   if (Error E = irsymtab::build(Mods, Symtab, StrtabBuilder, Alloc)) {
4621     consumeError(std::move(E));
4622     return;
4623   }
4624 
4625   writeBlob(bitc::SYMTAB_BLOCK_ID, bitc::SYMTAB_BLOB,
4626             {Symtab.data(), Symtab.size()});
4627 }
4628 
4629 void BitcodeWriter::writeStrtab() {
4630   assert(!WroteStrtab);
4631 
4632   std::vector<char> Strtab;
4633   StrtabBuilder.finalizeInOrder();
4634   Strtab.resize(StrtabBuilder.getSize());
4635   StrtabBuilder.write((uint8_t *)Strtab.data());
4636 
4637   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB,
4638             {Strtab.data(), Strtab.size()});
4639 
4640   WroteStrtab = true;
4641 }
4642 
4643 void BitcodeWriter::copyStrtab(StringRef Strtab) {
4644   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB, Strtab);
4645   WroteStrtab = true;
4646 }
4647 
4648 void BitcodeWriter::writeModule(const Module &M,
4649                                 bool ShouldPreserveUseListOrder,
4650                                 const ModuleSummaryIndex *Index,
4651                                 bool GenerateHash, ModuleHash *ModHash) {
4652   assert(!WroteStrtab);
4653 
4654   // The Mods vector is used by irsymtab::build, which requires non-const
4655   // Modules in case it needs to materialize metadata. But the bitcode writer
4656   // requires that the module is materialized, so we can cast to non-const here,
4657   // after checking that it is in fact materialized.
4658   assert(M.isMaterialized());
4659   Mods.push_back(const_cast<Module *>(&M));
4660 
4661   ModuleBitcodeWriter ModuleWriter(M, Buffer, StrtabBuilder, *Stream,
4662                                    ShouldPreserveUseListOrder, Index,
4663                                    GenerateHash, ModHash);
4664   ModuleWriter.write();
4665 }
4666 
4667 void BitcodeWriter::writeIndex(
4668     const ModuleSummaryIndex *Index,
4669     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4670   IndexBitcodeWriter IndexWriter(*Stream, StrtabBuilder, *Index,
4671                                  ModuleToSummariesForIndex);
4672   IndexWriter.write();
4673 }
4674 
4675 /// Write the specified module to the specified output stream.
4676 void llvm::WriteBitcodeToFile(const Module &M, raw_ostream &Out,
4677                               bool ShouldPreserveUseListOrder,
4678                               const ModuleSummaryIndex *Index,
4679                               bool GenerateHash, ModuleHash *ModHash) {
4680   SmallVector<char, 0> Buffer;
4681   Buffer.reserve(256*1024);
4682 
4683   // If this is darwin or another generic macho target, reserve space for the
4684   // header.
4685   Triple TT(M.getTargetTriple());
4686   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4687     Buffer.insert(Buffer.begin(), BWH_HeaderSize, 0);
4688 
4689   BitcodeWriter Writer(Buffer, dyn_cast<raw_fd_stream>(&Out));
4690   Writer.writeModule(M, ShouldPreserveUseListOrder, Index, GenerateHash,
4691                      ModHash);
4692   Writer.writeSymtab();
4693   Writer.writeStrtab();
4694 
4695   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4696     emitDarwinBCHeaderAndTrailer(Buffer, TT);
4697 
4698   // Write the generated bitstream to "Out".
4699   if (!Buffer.empty())
4700     Out.write((char *)&Buffer.front(), Buffer.size());
4701 }
4702 
4703 void IndexBitcodeWriter::write() {
4704   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4705 
4706   writeModuleVersion();
4707 
4708   // Write the module paths in the combined index.
4709   writeModStrings();
4710 
4711   // Write the summary combined index records.
4712   writeCombinedGlobalValueSummary();
4713 
4714   Stream.ExitBlock();
4715 }
4716 
4717 // Write the specified module summary index to the given raw output stream,
4718 // where it will be written in a new bitcode block. This is used when
4719 // writing the combined index file for ThinLTO. When writing a subset of the
4720 // index for a distributed backend, provide a \p ModuleToSummariesForIndex map.
4721 void llvm::writeIndexToFile(
4722     const ModuleSummaryIndex &Index, raw_ostream &Out,
4723     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4724   SmallVector<char, 0> Buffer;
4725   Buffer.reserve(256 * 1024);
4726 
4727   BitcodeWriter Writer(Buffer);
4728   Writer.writeIndex(&Index, ModuleToSummariesForIndex);
4729   Writer.writeStrtab();
4730 
4731   Out.write((char *)&Buffer.front(), Buffer.size());
4732 }
4733 
4734 namespace {
4735 
4736 /// Class to manage the bitcode writing for a thin link bitcode file.
4737 class ThinLinkBitcodeWriter : public ModuleBitcodeWriterBase {
4738   /// ModHash is for use in ThinLTO incremental build, generated while writing
4739   /// the module bitcode file.
4740   const ModuleHash *ModHash;
4741 
4742 public:
4743   ThinLinkBitcodeWriter(const Module &M, StringTableBuilder &StrtabBuilder,
4744                         BitstreamWriter &Stream,
4745                         const ModuleSummaryIndex &Index,
4746                         const ModuleHash &ModHash)
4747       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
4748                                 /*ShouldPreserveUseListOrder=*/false, &Index),
4749         ModHash(&ModHash) {}
4750 
4751   void write();
4752 
4753 private:
4754   void writeSimplifiedModuleInfo();
4755 };
4756 
4757 } // end anonymous namespace
4758 
4759 // This function writes a simpilified module info for thin link bitcode file.
4760 // It only contains the source file name along with the name(the offset and
4761 // size in strtab) and linkage for global values. For the global value info
4762 // entry, in order to keep linkage at offset 5, there are three zeros used
4763 // as padding.
4764 void ThinLinkBitcodeWriter::writeSimplifiedModuleInfo() {
4765   SmallVector<unsigned, 64> Vals;
4766   // Emit the module's source file name.
4767   {
4768     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
4769     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
4770     if (Bits == SE_Char6)
4771       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
4772     else if (Bits == SE_Fixed7)
4773       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
4774 
4775     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
4776     auto Abbv = std::make_shared<BitCodeAbbrev>();
4777     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
4778     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4779     Abbv->Add(AbbrevOpToUse);
4780     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4781 
4782     for (const auto P : M.getSourceFileName())
4783       Vals.push_back((unsigned char)P);
4784 
4785     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
4786     Vals.clear();
4787   }
4788 
4789   // Emit the global variable information.
4790   for (const GlobalVariable &GV : M.globals()) {
4791     // GLOBALVAR: [strtab offset, strtab size, 0, 0, 0, linkage]
4792     Vals.push_back(StrtabBuilder.add(GV.getName()));
4793     Vals.push_back(GV.getName().size());
4794     Vals.push_back(0);
4795     Vals.push_back(0);
4796     Vals.push_back(0);
4797     Vals.push_back(getEncodedLinkage(GV));
4798 
4799     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals);
4800     Vals.clear();
4801   }
4802 
4803   // Emit the function proto information.
4804   for (const Function &F : M) {
4805     // FUNCTION:  [strtab offset, strtab size, 0, 0, 0, linkage]
4806     Vals.push_back(StrtabBuilder.add(F.getName()));
4807     Vals.push_back(F.getName().size());
4808     Vals.push_back(0);
4809     Vals.push_back(0);
4810     Vals.push_back(0);
4811     Vals.push_back(getEncodedLinkage(F));
4812 
4813     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals);
4814     Vals.clear();
4815   }
4816 
4817   // Emit the alias information.
4818   for (const GlobalAlias &A : M.aliases()) {
4819     // ALIAS: [strtab offset, strtab size, 0, 0, 0, linkage]
4820     Vals.push_back(StrtabBuilder.add(A.getName()));
4821     Vals.push_back(A.getName().size());
4822     Vals.push_back(0);
4823     Vals.push_back(0);
4824     Vals.push_back(0);
4825     Vals.push_back(getEncodedLinkage(A));
4826 
4827     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals);
4828     Vals.clear();
4829   }
4830 
4831   // Emit the ifunc information.
4832   for (const GlobalIFunc &I : M.ifuncs()) {
4833     // IFUNC: [strtab offset, strtab size, 0, 0, 0, linkage]
4834     Vals.push_back(StrtabBuilder.add(I.getName()));
4835     Vals.push_back(I.getName().size());
4836     Vals.push_back(0);
4837     Vals.push_back(0);
4838     Vals.push_back(0);
4839     Vals.push_back(getEncodedLinkage(I));
4840 
4841     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
4842     Vals.clear();
4843   }
4844 }
4845 
4846 void ThinLinkBitcodeWriter::write() {
4847   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4848 
4849   writeModuleVersion();
4850 
4851   writeSimplifiedModuleInfo();
4852 
4853   writePerModuleGlobalValueSummary();
4854 
4855   // Write module hash.
4856   Stream.EmitRecord(bitc::MODULE_CODE_HASH, ArrayRef<uint32_t>(*ModHash));
4857 
4858   Stream.ExitBlock();
4859 }
4860 
4861 void BitcodeWriter::writeThinLinkBitcode(const Module &M,
4862                                          const ModuleSummaryIndex &Index,
4863                                          const ModuleHash &ModHash) {
4864   assert(!WroteStrtab);
4865 
4866   // The Mods vector is used by irsymtab::build, which requires non-const
4867   // Modules in case it needs to materialize metadata. But the bitcode writer
4868   // requires that the module is materialized, so we can cast to non-const here,
4869   // after checking that it is in fact materialized.
4870   assert(M.isMaterialized());
4871   Mods.push_back(const_cast<Module *>(&M));
4872 
4873   ThinLinkBitcodeWriter ThinLinkWriter(M, StrtabBuilder, *Stream, Index,
4874                                        ModHash);
4875   ThinLinkWriter.write();
4876 }
4877 
4878 // Write the specified thin link bitcode file to the given raw output stream,
4879 // where it will be written in a new bitcode block. This is used when
4880 // writing the per-module index file for ThinLTO.
4881 void llvm::writeThinLinkBitcodeToFile(const Module &M, raw_ostream &Out,
4882                                       const ModuleSummaryIndex &Index,
4883                                       const ModuleHash &ModHash) {
4884   SmallVector<char, 0> Buffer;
4885   Buffer.reserve(256 * 1024);
4886 
4887   BitcodeWriter Writer(Buffer);
4888   Writer.writeThinLinkBitcode(M, Index, ModHash);
4889   Writer.writeSymtab();
4890   Writer.writeStrtab();
4891 
4892   Out.write((char *)&Buffer.front(), Buffer.size());
4893 }
4894 
4895 static const char *getSectionNameForBitcode(const Triple &T) {
4896   switch (T.getObjectFormat()) {
4897   case Triple::MachO:
4898     return "__LLVM,__bitcode";
4899   case Triple::COFF:
4900   case Triple::ELF:
4901   case Triple::Wasm:
4902   case Triple::UnknownObjectFormat:
4903     return ".llvmbc";
4904   case Triple::GOFF:
4905     llvm_unreachable("GOFF is not yet implemented");
4906     break;
4907   case Triple::SPIRV:
4908     llvm_unreachable("SPIRV is not yet implemented");
4909     break;
4910   case Triple::XCOFF:
4911     llvm_unreachable("XCOFF is not yet implemented");
4912     break;
4913   case Triple::DXContainer:
4914     llvm_unreachable("DXContainer is not yet implemented");
4915     break;
4916   }
4917   llvm_unreachable("Unimplemented ObjectFormatType");
4918 }
4919 
4920 static const char *getSectionNameForCommandline(const Triple &T) {
4921   switch (T.getObjectFormat()) {
4922   case Triple::MachO:
4923     return "__LLVM,__cmdline";
4924   case Triple::COFF:
4925   case Triple::ELF:
4926   case Triple::Wasm:
4927   case Triple::UnknownObjectFormat:
4928     return ".llvmcmd";
4929   case Triple::GOFF:
4930     llvm_unreachable("GOFF is not yet implemented");
4931     break;
4932   case Triple::SPIRV:
4933     llvm_unreachable("SPIRV is not yet implemented");
4934     break;
4935   case Triple::XCOFF:
4936     llvm_unreachable("XCOFF is not yet implemented");
4937     break;
4938   case Triple::DXContainer:
4939     llvm_unreachable("DXC is not yet implemented");
4940     break;
4941   }
4942   llvm_unreachable("Unimplemented ObjectFormatType");
4943 }
4944 
4945 void llvm::embedBitcodeInModule(llvm::Module &M, llvm::MemoryBufferRef Buf,
4946                                 bool EmbedBitcode, bool EmbedCmdline,
4947                                 const std::vector<uint8_t> &CmdArgs) {
4948   // Save llvm.compiler.used and remove it.
4949   SmallVector<Constant *, 2> UsedArray;
4950   SmallVector<GlobalValue *, 4> UsedGlobals;
4951   Type *UsedElementType = Type::getInt8Ty(M.getContext())->getPointerTo(0);
4952   GlobalVariable *Used = collectUsedGlobalVariables(M, UsedGlobals, true);
4953   for (auto *GV : UsedGlobals) {
4954     if (GV->getName() != "llvm.embedded.module" &&
4955         GV->getName() != "llvm.cmdline")
4956       UsedArray.push_back(
4957           ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
4958   }
4959   if (Used)
4960     Used->eraseFromParent();
4961 
4962   // Embed the bitcode for the llvm module.
4963   std::string Data;
4964   ArrayRef<uint8_t> ModuleData;
4965   Triple T(M.getTargetTriple());
4966 
4967   if (EmbedBitcode) {
4968     if (Buf.getBufferSize() == 0 ||
4969         !isBitcode((const unsigned char *)Buf.getBufferStart(),
4970                    (const unsigned char *)Buf.getBufferEnd())) {
4971       // If the input is LLVM Assembly, bitcode is produced by serializing
4972       // the module. Use-lists order need to be preserved in this case.
4973       llvm::raw_string_ostream OS(Data);
4974       llvm::WriteBitcodeToFile(M, OS, /* ShouldPreserveUseListOrder */ true);
4975       ModuleData =
4976           ArrayRef<uint8_t>((const uint8_t *)OS.str().data(), OS.str().size());
4977     } else
4978       // If the input is LLVM bitcode, write the input byte stream directly.
4979       ModuleData = ArrayRef<uint8_t>((const uint8_t *)Buf.getBufferStart(),
4980                                      Buf.getBufferSize());
4981   }
4982   llvm::Constant *ModuleConstant =
4983       llvm::ConstantDataArray::get(M.getContext(), ModuleData);
4984   llvm::GlobalVariable *GV = new llvm::GlobalVariable(
4985       M, ModuleConstant->getType(), true, llvm::GlobalValue::PrivateLinkage,
4986       ModuleConstant);
4987   GV->setSection(getSectionNameForBitcode(T));
4988   // Set alignment to 1 to prevent padding between two contributions from input
4989   // sections after linking.
4990   GV->setAlignment(Align(1));
4991   UsedArray.push_back(
4992       ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
4993   if (llvm::GlobalVariable *Old =
4994           M.getGlobalVariable("llvm.embedded.module", true)) {
4995     assert(Old->hasZeroLiveUses() &&
4996            "llvm.embedded.module can only be used once in llvm.compiler.used");
4997     GV->takeName(Old);
4998     Old->eraseFromParent();
4999   } else {
5000     GV->setName("llvm.embedded.module");
5001   }
5002 
5003   // Skip if only bitcode needs to be embedded.
5004   if (EmbedCmdline) {
5005     // Embed command-line options.
5006     ArrayRef<uint8_t> CmdData(const_cast<uint8_t *>(CmdArgs.data()),
5007                               CmdArgs.size());
5008     llvm::Constant *CmdConstant =
5009         llvm::ConstantDataArray::get(M.getContext(), CmdData);
5010     GV = new llvm::GlobalVariable(M, CmdConstant->getType(), true,
5011                                   llvm::GlobalValue::PrivateLinkage,
5012                                   CmdConstant);
5013     GV->setSection(getSectionNameForCommandline(T));
5014     GV->setAlignment(Align(1));
5015     UsedArray.push_back(
5016         ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
5017     if (llvm::GlobalVariable *Old = M.getGlobalVariable("llvm.cmdline", true)) {
5018       assert(Old->hasZeroLiveUses() &&
5019              "llvm.cmdline can only be used once in llvm.compiler.used");
5020       GV->takeName(Old);
5021       Old->eraseFromParent();
5022     } else {
5023       GV->setName("llvm.cmdline");
5024     }
5025   }
5026 
5027   if (UsedArray.empty())
5028     return;
5029 
5030   // Recreate llvm.compiler.used.
5031   ArrayType *ATy = ArrayType::get(UsedElementType, UsedArray.size());
5032   auto *NewUsed = new GlobalVariable(
5033       M, ATy, false, llvm::GlobalValue::AppendingLinkage,
5034       llvm::ConstantArray::get(ATy, UsedArray), "llvm.compiler.used");
5035   NewUsed->setSection("llvm.metadata");
5036 }
5037