xref: /llvm-project/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp (revision 7283f48a05de46fe8721ee6c29b1b6427e7d1a33)
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::PresplitCoroutine:
778     return bitc::ATTR_KIND_PRESPLIT_COROUTINE;
779   case Attribute::EndAttrKinds:
780     llvm_unreachable("Can not encode end-attribute kinds marker.");
781   case Attribute::None:
782     llvm_unreachable("Can not encode none-attribute.");
783   case Attribute::EmptyKey:
784   case Attribute::TombstoneKey:
785     llvm_unreachable("Trying to encode EmptyKey/TombstoneKey");
786   }
787 
788   llvm_unreachable("Trying to encode unknown attribute");
789 }
790 
791 void ModuleBitcodeWriter::writeAttributeGroupTable() {
792   const std::vector<ValueEnumerator::IndexAndAttrSet> &AttrGrps =
793       VE.getAttributeGroups();
794   if (AttrGrps.empty()) return;
795 
796   Stream.EnterSubblock(bitc::PARAMATTR_GROUP_BLOCK_ID, 3);
797 
798   SmallVector<uint64_t, 64> Record;
799   for (ValueEnumerator::IndexAndAttrSet Pair : AttrGrps) {
800     unsigned AttrListIndex = Pair.first;
801     AttributeSet AS = Pair.second;
802     Record.push_back(VE.getAttributeGroupID(Pair));
803     Record.push_back(AttrListIndex);
804 
805     for (Attribute Attr : AS) {
806       if (Attr.isEnumAttribute()) {
807         Record.push_back(0);
808         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
809       } else if (Attr.isIntAttribute()) {
810         Record.push_back(1);
811         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
812         Record.push_back(Attr.getValueAsInt());
813       } else if (Attr.isStringAttribute()) {
814         StringRef Kind = Attr.getKindAsString();
815         StringRef Val = Attr.getValueAsString();
816 
817         Record.push_back(Val.empty() ? 3 : 4);
818         Record.append(Kind.begin(), Kind.end());
819         Record.push_back(0);
820         if (!Val.empty()) {
821           Record.append(Val.begin(), Val.end());
822           Record.push_back(0);
823         }
824       } else {
825         assert(Attr.isTypeAttribute());
826         Type *Ty = Attr.getValueAsType();
827         Record.push_back(Ty ? 6 : 5);
828         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
829         if (Ty)
830           Record.push_back(VE.getTypeID(Attr.getValueAsType()));
831       }
832     }
833 
834     Stream.EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
835     Record.clear();
836   }
837 
838   Stream.ExitBlock();
839 }
840 
841 void ModuleBitcodeWriter::writeAttributeTable() {
842   const std::vector<AttributeList> &Attrs = VE.getAttributeLists();
843   if (Attrs.empty()) return;
844 
845   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
846 
847   SmallVector<uint64_t, 64> Record;
848   for (const AttributeList &AL : Attrs) {
849     for (unsigned i : AL.indexes()) {
850       AttributeSet AS = AL.getAttributes(i);
851       if (AS.hasAttributes())
852         Record.push_back(VE.getAttributeGroupID({i, AS}));
853     }
854 
855     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
856     Record.clear();
857   }
858 
859   Stream.ExitBlock();
860 }
861 
862 /// WriteTypeTable - Write out the type table for a module.
863 void ModuleBitcodeWriter::writeTypeTable() {
864   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
865 
866   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
867   SmallVector<uint64_t, 64> TypeVals;
868 
869   uint64_t NumBits = VE.computeBitsRequiredForTypeIndicies();
870 
871   // Abbrev for TYPE_CODE_POINTER.
872   auto Abbv = std::make_shared<BitCodeAbbrev>();
873   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
874   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
875   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
876   unsigned PtrAbbrev = Stream.EmitAbbrev(std::move(Abbv));
877 
878   // Abbrev for TYPE_CODE_OPAQUE_POINTER.
879   Abbv = std::make_shared<BitCodeAbbrev>();
880   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_OPAQUE_POINTER));
881   Abbv->Add(BitCodeAbbrevOp(0)); // Addrspace = 0
882   unsigned OpaquePtrAbbrev = Stream.EmitAbbrev(std::move(Abbv));
883 
884   // Abbrev for TYPE_CODE_FUNCTION.
885   Abbv = std::make_shared<BitCodeAbbrev>();
886   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
887   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
888   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
889   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
890   unsigned FunctionAbbrev = Stream.EmitAbbrev(std::move(Abbv));
891 
892   // Abbrev for TYPE_CODE_STRUCT_ANON.
893   Abbv = std::make_shared<BitCodeAbbrev>();
894   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
895   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
896   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
897   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
898   unsigned StructAnonAbbrev = Stream.EmitAbbrev(std::move(Abbv));
899 
900   // Abbrev for TYPE_CODE_STRUCT_NAME.
901   Abbv = std::make_shared<BitCodeAbbrev>();
902   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
903   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
904   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
905   unsigned StructNameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
906 
907   // Abbrev for TYPE_CODE_STRUCT_NAMED.
908   Abbv = std::make_shared<BitCodeAbbrev>();
909   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
910   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
911   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
912   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
913   unsigned StructNamedAbbrev = Stream.EmitAbbrev(std::move(Abbv));
914 
915   // Abbrev for TYPE_CODE_ARRAY.
916   Abbv = std::make_shared<BitCodeAbbrev>();
917   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
918   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
919   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
920   unsigned ArrayAbbrev = Stream.EmitAbbrev(std::move(Abbv));
921 
922   // Emit an entry count so the reader can reserve space.
923   TypeVals.push_back(TypeList.size());
924   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
925   TypeVals.clear();
926 
927   // Loop over all of the types, emitting each in turn.
928   for (Type *T : TypeList) {
929     int AbbrevToUse = 0;
930     unsigned Code = 0;
931 
932     switch (T->getTypeID()) {
933     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;      break;
934     case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;      break;
935     case Type::BFloatTyID:    Code = bitc::TYPE_CODE_BFLOAT;    break;
936     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;     break;
937     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE;    break;
938     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80;  break;
939     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128;     break;
940     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
941     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;     break;
942     case Type::MetadataTyID:  Code = bitc::TYPE_CODE_METADATA;  break;
943     case Type::X86_MMXTyID:   Code = bitc::TYPE_CODE_X86_MMX;   break;
944     case Type::X86_AMXTyID:   Code = bitc::TYPE_CODE_X86_AMX;   break;
945     case Type::TokenTyID:     Code = bitc::TYPE_CODE_TOKEN;     break;
946     case Type::IntegerTyID:
947       // INTEGER: [width]
948       Code = bitc::TYPE_CODE_INTEGER;
949       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
950       break;
951     case Type::PointerTyID: {
952       PointerType *PTy = cast<PointerType>(T);
953       unsigned AddressSpace = PTy->getAddressSpace();
954       if (PTy->isOpaque()) {
955         // OPAQUE_POINTER: [address space]
956         Code = bitc::TYPE_CODE_OPAQUE_POINTER;
957         TypeVals.push_back(AddressSpace);
958         if (AddressSpace == 0)
959           AbbrevToUse = OpaquePtrAbbrev;
960       } else {
961         // POINTER: [pointee type, address space]
962         Code = bitc::TYPE_CODE_POINTER;
963         TypeVals.push_back(VE.getTypeID(PTy->getNonOpaquePointerElementType()));
964         TypeVals.push_back(AddressSpace);
965         if (AddressSpace == 0)
966           AbbrevToUse = PtrAbbrev;
967       }
968       break;
969     }
970     case Type::FunctionTyID: {
971       FunctionType *FT = cast<FunctionType>(T);
972       // FUNCTION: [isvararg, retty, paramty x N]
973       Code = bitc::TYPE_CODE_FUNCTION;
974       TypeVals.push_back(FT->isVarArg());
975       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
976       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
977         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
978       AbbrevToUse = FunctionAbbrev;
979       break;
980     }
981     case Type::StructTyID: {
982       StructType *ST = cast<StructType>(T);
983       // STRUCT: [ispacked, eltty x N]
984       TypeVals.push_back(ST->isPacked());
985       // Output all of the element types.
986       for (Type *ET : ST->elements())
987         TypeVals.push_back(VE.getTypeID(ET));
988 
989       if (ST->isLiteral()) {
990         Code = bitc::TYPE_CODE_STRUCT_ANON;
991         AbbrevToUse = StructAnonAbbrev;
992       } else {
993         if (ST->isOpaque()) {
994           Code = bitc::TYPE_CODE_OPAQUE;
995         } else {
996           Code = bitc::TYPE_CODE_STRUCT_NAMED;
997           AbbrevToUse = StructNamedAbbrev;
998         }
999 
1000         // Emit the name if it is present.
1001         if (!ST->getName().empty())
1002           writeStringRecord(Stream, bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
1003                             StructNameAbbrev);
1004       }
1005       break;
1006     }
1007     case Type::ArrayTyID: {
1008       ArrayType *AT = cast<ArrayType>(T);
1009       // ARRAY: [numelts, eltty]
1010       Code = bitc::TYPE_CODE_ARRAY;
1011       TypeVals.push_back(AT->getNumElements());
1012       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
1013       AbbrevToUse = ArrayAbbrev;
1014       break;
1015     }
1016     case Type::FixedVectorTyID:
1017     case Type::ScalableVectorTyID: {
1018       VectorType *VT = cast<VectorType>(T);
1019       // VECTOR [numelts, eltty] or
1020       //        [numelts, eltty, scalable]
1021       Code = bitc::TYPE_CODE_VECTOR;
1022       TypeVals.push_back(VT->getElementCount().getKnownMinValue());
1023       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
1024       if (isa<ScalableVectorType>(VT))
1025         TypeVals.push_back(true);
1026       break;
1027     }
1028     case Type::DXILPointerTyID:
1029       llvm_unreachable("DXIL pointers cannot be added to IR modules");
1030     }
1031 
1032     // Emit the finished record.
1033     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
1034     TypeVals.clear();
1035   }
1036 
1037   Stream.ExitBlock();
1038 }
1039 
1040 static unsigned getEncodedLinkage(const GlobalValue::LinkageTypes Linkage) {
1041   switch (Linkage) {
1042   case GlobalValue::ExternalLinkage:
1043     return 0;
1044   case GlobalValue::WeakAnyLinkage:
1045     return 16;
1046   case GlobalValue::AppendingLinkage:
1047     return 2;
1048   case GlobalValue::InternalLinkage:
1049     return 3;
1050   case GlobalValue::LinkOnceAnyLinkage:
1051     return 18;
1052   case GlobalValue::ExternalWeakLinkage:
1053     return 7;
1054   case GlobalValue::CommonLinkage:
1055     return 8;
1056   case GlobalValue::PrivateLinkage:
1057     return 9;
1058   case GlobalValue::WeakODRLinkage:
1059     return 17;
1060   case GlobalValue::LinkOnceODRLinkage:
1061     return 19;
1062   case GlobalValue::AvailableExternallyLinkage:
1063     return 12;
1064   }
1065   llvm_unreachable("Invalid linkage");
1066 }
1067 
1068 static unsigned getEncodedLinkage(const GlobalValue &GV) {
1069   return getEncodedLinkage(GV.getLinkage());
1070 }
1071 
1072 static uint64_t getEncodedFFlags(FunctionSummary::FFlags Flags) {
1073   uint64_t RawFlags = 0;
1074   RawFlags |= Flags.ReadNone;
1075   RawFlags |= (Flags.ReadOnly << 1);
1076   RawFlags |= (Flags.NoRecurse << 2);
1077   RawFlags |= (Flags.ReturnDoesNotAlias << 3);
1078   RawFlags |= (Flags.NoInline << 4);
1079   RawFlags |= (Flags.AlwaysInline << 5);
1080   RawFlags |= (Flags.NoUnwind << 6);
1081   RawFlags |= (Flags.MayThrow << 7);
1082   RawFlags |= (Flags.HasUnknownCall << 8);
1083   RawFlags |= (Flags.MustBeUnreachable << 9);
1084   return RawFlags;
1085 }
1086 
1087 // Decode the flags for GlobalValue in the summary. See getDecodedGVSummaryFlags
1088 // in BitcodeReader.cpp.
1089 static uint64_t getEncodedGVSummaryFlags(GlobalValueSummary::GVFlags Flags) {
1090   uint64_t RawFlags = 0;
1091 
1092   RawFlags |= Flags.NotEligibleToImport; // bool
1093   RawFlags |= (Flags.Live << 1);
1094   RawFlags |= (Flags.DSOLocal << 2);
1095   RawFlags |= (Flags.CanAutoHide << 3);
1096 
1097   // Linkage don't need to be remapped at that time for the summary. Any future
1098   // change to the getEncodedLinkage() function will need to be taken into
1099   // account here as well.
1100   RawFlags = (RawFlags << 4) | Flags.Linkage; // 4 bits
1101 
1102   RawFlags |= (Flags.Visibility << 8); // 2 bits
1103 
1104   return RawFlags;
1105 }
1106 
1107 static uint64_t getEncodedGVarFlags(GlobalVarSummary::GVarFlags Flags) {
1108   uint64_t RawFlags = Flags.MaybeReadOnly | (Flags.MaybeWriteOnly << 1) |
1109                       (Flags.Constant << 2) | Flags.VCallVisibility << 3;
1110   return RawFlags;
1111 }
1112 
1113 static unsigned getEncodedVisibility(const GlobalValue &GV) {
1114   switch (GV.getVisibility()) {
1115   case GlobalValue::DefaultVisibility:   return 0;
1116   case GlobalValue::HiddenVisibility:    return 1;
1117   case GlobalValue::ProtectedVisibility: return 2;
1118   }
1119   llvm_unreachable("Invalid visibility");
1120 }
1121 
1122 static unsigned getEncodedDLLStorageClass(const GlobalValue &GV) {
1123   switch (GV.getDLLStorageClass()) {
1124   case GlobalValue::DefaultStorageClass:   return 0;
1125   case GlobalValue::DLLImportStorageClass: return 1;
1126   case GlobalValue::DLLExportStorageClass: return 2;
1127   }
1128   llvm_unreachable("Invalid DLL storage class");
1129 }
1130 
1131 static unsigned getEncodedThreadLocalMode(const GlobalValue &GV) {
1132   switch (GV.getThreadLocalMode()) {
1133     case GlobalVariable::NotThreadLocal:         return 0;
1134     case GlobalVariable::GeneralDynamicTLSModel: return 1;
1135     case GlobalVariable::LocalDynamicTLSModel:   return 2;
1136     case GlobalVariable::InitialExecTLSModel:    return 3;
1137     case GlobalVariable::LocalExecTLSModel:      return 4;
1138   }
1139   llvm_unreachable("Invalid TLS model");
1140 }
1141 
1142 static unsigned getEncodedComdatSelectionKind(const Comdat &C) {
1143   switch (C.getSelectionKind()) {
1144   case Comdat::Any:
1145     return bitc::COMDAT_SELECTION_KIND_ANY;
1146   case Comdat::ExactMatch:
1147     return bitc::COMDAT_SELECTION_KIND_EXACT_MATCH;
1148   case Comdat::Largest:
1149     return bitc::COMDAT_SELECTION_KIND_LARGEST;
1150   case Comdat::NoDeduplicate:
1151     return bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES;
1152   case Comdat::SameSize:
1153     return bitc::COMDAT_SELECTION_KIND_SAME_SIZE;
1154   }
1155   llvm_unreachable("Invalid selection kind");
1156 }
1157 
1158 static unsigned getEncodedUnnamedAddr(const GlobalValue &GV) {
1159   switch (GV.getUnnamedAddr()) {
1160   case GlobalValue::UnnamedAddr::None:   return 0;
1161   case GlobalValue::UnnamedAddr::Local:  return 2;
1162   case GlobalValue::UnnamedAddr::Global: return 1;
1163   }
1164   llvm_unreachable("Invalid unnamed_addr");
1165 }
1166 
1167 size_t ModuleBitcodeWriter::addToStrtab(StringRef Str) {
1168   if (GenerateHash)
1169     Hasher.update(Str);
1170   return StrtabBuilder.add(Str);
1171 }
1172 
1173 void ModuleBitcodeWriter::writeComdats() {
1174   SmallVector<unsigned, 64> Vals;
1175   for (const Comdat *C : VE.getComdats()) {
1176     // COMDAT: [strtab offset, strtab size, selection_kind]
1177     Vals.push_back(addToStrtab(C->getName()));
1178     Vals.push_back(C->getName().size());
1179     Vals.push_back(getEncodedComdatSelectionKind(*C));
1180     Stream.EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
1181     Vals.clear();
1182   }
1183 }
1184 
1185 /// Write a record that will eventually hold the word offset of the
1186 /// module-level VST. For now the offset is 0, which will be backpatched
1187 /// after the real VST is written. Saves the bit offset to backpatch.
1188 void ModuleBitcodeWriter::writeValueSymbolTableForwardDecl() {
1189   // Write a placeholder value in for the offset of the real VST,
1190   // which is written after the function blocks so that it can include
1191   // the offset of each function. The placeholder offset will be
1192   // updated when the real VST is written.
1193   auto Abbv = std::make_shared<BitCodeAbbrev>();
1194   Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_VSTOFFSET));
1195   // Blocks are 32-bit aligned, so we can use a 32-bit word offset to
1196   // hold the real VST offset. Must use fixed instead of VBR as we don't
1197   // know how many VBR chunks to reserve ahead of time.
1198   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
1199   unsigned VSTOffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1200 
1201   // Emit the placeholder
1202   uint64_t Vals[] = {bitc::MODULE_CODE_VSTOFFSET, 0};
1203   Stream.EmitRecordWithAbbrev(VSTOffsetAbbrev, Vals);
1204 
1205   // Compute and save the bit offset to the placeholder, which will be
1206   // patched when the real VST is written. We can simply subtract the 32-bit
1207   // fixed size from the current bit number to get the location to backpatch.
1208   VSTOffsetPlaceholder = Stream.GetCurrentBitNo() - 32;
1209 }
1210 
1211 enum StringEncoding { SE_Char6, SE_Fixed7, SE_Fixed8 };
1212 
1213 /// Determine the encoding to use for the given string name and length.
1214 static StringEncoding getStringEncoding(StringRef Str) {
1215   bool isChar6 = true;
1216   for (char C : Str) {
1217     if (isChar6)
1218       isChar6 = BitCodeAbbrevOp::isChar6(C);
1219     if ((unsigned char)C & 128)
1220       // don't bother scanning the rest.
1221       return SE_Fixed8;
1222   }
1223   if (isChar6)
1224     return SE_Char6;
1225   return SE_Fixed7;
1226 }
1227 
1228 static_assert(sizeof(GlobalValue::SanitizerMetadata) <= sizeof(unsigned),
1229               "Sanitizer Metadata is too large for naive serialization.");
1230 static unsigned
1231 serializeSanitizerMetadata(const GlobalValue::SanitizerMetadata &Meta) {
1232   return Meta.NoAddress | (Meta.NoHWAddress << 1) |
1233          (Meta.NoMemtag << 2) | (Meta.IsDynInit << 3);
1234 }
1235 
1236 /// Emit top-level description of module, including target triple, inline asm,
1237 /// descriptors for global variables, and function prototype info.
1238 /// Returns the bit offset to backpatch with the location of the real VST.
1239 void ModuleBitcodeWriter::writeModuleInfo() {
1240   // Emit various pieces of data attached to a module.
1241   if (!M.getTargetTriple().empty())
1242     writeStringRecord(Stream, bitc::MODULE_CODE_TRIPLE, M.getTargetTriple(),
1243                       0 /*TODO*/);
1244   const std::string &DL = M.getDataLayoutStr();
1245   if (!DL.empty())
1246     writeStringRecord(Stream, bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/);
1247   if (!M.getModuleInlineAsm().empty())
1248     writeStringRecord(Stream, bitc::MODULE_CODE_ASM, M.getModuleInlineAsm(),
1249                       0 /*TODO*/);
1250 
1251   // Emit information about sections and GC, computing how many there are. Also
1252   // compute the maximum alignment value.
1253   std::map<std::string, unsigned> SectionMap;
1254   std::map<std::string, unsigned> GCMap;
1255   MaybeAlign MaxAlignment;
1256   unsigned MaxGlobalType = 0;
1257   const auto UpdateMaxAlignment = [&MaxAlignment](const MaybeAlign A) {
1258     if (A)
1259       MaxAlignment = !MaxAlignment ? *A : std::max(*MaxAlignment, *A);
1260   };
1261   for (const GlobalVariable &GV : M.globals()) {
1262     UpdateMaxAlignment(GV.getAlign());
1263     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getValueType()));
1264     if (GV.hasSection()) {
1265       // Give section names unique ID's.
1266       unsigned &Entry = SectionMap[std::string(GV.getSection())];
1267       if (!Entry) {
1268         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
1269                           0 /*TODO*/);
1270         Entry = SectionMap.size();
1271       }
1272     }
1273   }
1274   for (const Function &F : M) {
1275     UpdateMaxAlignment(F.getAlign());
1276     if (F.hasSection()) {
1277       // Give section names unique ID's.
1278       unsigned &Entry = SectionMap[std::string(F.getSection())];
1279       if (!Entry) {
1280         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
1281                           0 /*TODO*/);
1282         Entry = SectionMap.size();
1283       }
1284     }
1285     if (F.hasGC()) {
1286       // Same for GC names.
1287       unsigned &Entry = GCMap[F.getGC()];
1288       if (!Entry) {
1289         writeStringRecord(Stream, bitc::MODULE_CODE_GCNAME, F.getGC(),
1290                           0 /*TODO*/);
1291         Entry = GCMap.size();
1292       }
1293     }
1294   }
1295 
1296   // Emit abbrev for globals, now that we know # sections and max alignment.
1297   unsigned SimpleGVarAbbrev = 0;
1298   if (!M.global_empty()) {
1299     // Add an abbrev for common globals with no visibility or thread localness.
1300     auto Abbv = std::make_shared<BitCodeAbbrev>();
1301     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
1302     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1303     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1304     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1305                               Log2_32_Ceil(MaxGlobalType+1)));
1306     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddrSpace << 2
1307                                                            //| explicitType << 1
1308                                                            //| constant
1309     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Initializer.
1310     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // Linkage.
1311     if (!MaxAlignment)                                     // Alignment.
1312       Abbv->Add(BitCodeAbbrevOp(0));
1313     else {
1314       unsigned MaxEncAlignment = getEncodedAlign(MaxAlignment);
1315       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1316                                Log2_32_Ceil(MaxEncAlignment+1)));
1317     }
1318     if (SectionMap.empty())                                    // Section.
1319       Abbv->Add(BitCodeAbbrevOp(0));
1320     else
1321       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1322                                Log2_32_Ceil(SectionMap.size()+1)));
1323     // Don't bother emitting vis + thread local.
1324     SimpleGVarAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1325   }
1326 
1327   SmallVector<unsigned, 64> Vals;
1328   // Emit the module's source file name.
1329   {
1330     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
1331     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
1332     if (Bits == SE_Char6)
1333       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
1334     else if (Bits == SE_Fixed7)
1335       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
1336 
1337     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
1338     auto Abbv = std::make_shared<BitCodeAbbrev>();
1339     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
1340     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1341     Abbv->Add(AbbrevOpToUse);
1342     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1343 
1344     for (const auto P : M.getSourceFileName())
1345       Vals.push_back((unsigned char)P);
1346 
1347     // Emit the finished record.
1348     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
1349     Vals.clear();
1350   }
1351 
1352   // Emit the global variable information.
1353   for (const GlobalVariable &GV : M.globals()) {
1354     unsigned AbbrevToUse = 0;
1355 
1356     // GLOBALVAR: [strtab offset, strtab size, type, isconst, initid,
1357     //             linkage, alignment, section, visibility, threadlocal,
1358     //             unnamed_addr, externally_initialized, dllstorageclass,
1359     //             comdat, attributes, DSO_Local, GlobalSanitizer]
1360     Vals.push_back(addToStrtab(GV.getName()));
1361     Vals.push_back(GV.getName().size());
1362     Vals.push_back(VE.getTypeID(GV.getValueType()));
1363     Vals.push_back(GV.getType()->getAddressSpace() << 2 | 2 | GV.isConstant());
1364     Vals.push_back(GV.isDeclaration() ? 0 :
1365                    (VE.getValueID(GV.getInitializer()) + 1));
1366     Vals.push_back(getEncodedLinkage(GV));
1367     Vals.push_back(getEncodedAlign(GV.getAlign()));
1368     Vals.push_back(GV.hasSection() ? SectionMap[std::string(GV.getSection())]
1369                                    : 0);
1370     if (GV.isThreadLocal() ||
1371         GV.getVisibility() != GlobalValue::DefaultVisibility ||
1372         GV.getUnnamedAddr() != GlobalValue::UnnamedAddr::None ||
1373         GV.isExternallyInitialized() ||
1374         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
1375         GV.hasComdat() || GV.hasAttributes() || GV.isDSOLocal() ||
1376         GV.hasPartition() || GV.hasSanitizerMetadata()) {
1377       Vals.push_back(getEncodedVisibility(GV));
1378       Vals.push_back(getEncodedThreadLocalMode(GV));
1379       Vals.push_back(getEncodedUnnamedAddr(GV));
1380       Vals.push_back(GV.isExternallyInitialized());
1381       Vals.push_back(getEncodedDLLStorageClass(GV));
1382       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
1383 
1384       auto AL = GV.getAttributesAsList(AttributeList::FunctionIndex);
1385       Vals.push_back(VE.getAttributeListID(AL));
1386 
1387       Vals.push_back(GV.isDSOLocal());
1388       Vals.push_back(addToStrtab(GV.getPartition()));
1389       Vals.push_back(GV.getPartition().size());
1390 
1391       Vals.push_back((GV.hasSanitizerMetadata() ? serializeSanitizerMetadata(
1392                                                       GV.getSanitizerMetadata())
1393                                                 : 0));
1394     } else {
1395       AbbrevToUse = SimpleGVarAbbrev;
1396     }
1397 
1398     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
1399     Vals.clear();
1400   }
1401 
1402   // Emit the function proto information.
1403   for (const Function &F : M) {
1404     // FUNCTION:  [strtab offset, strtab size, type, callingconv, isproto,
1405     //             linkage, paramattrs, alignment, section, visibility, gc,
1406     //             unnamed_addr, prologuedata, dllstorageclass, comdat,
1407     //             prefixdata, personalityfn, DSO_Local, addrspace]
1408     Vals.push_back(addToStrtab(F.getName()));
1409     Vals.push_back(F.getName().size());
1410     Vals.push_back(VE.getTypeID(F.getFunctionType()));
1411     Vals.push_back(F.getCallingConv());
1412     Vals.push_back(F.isDeclaration());
1413     Vals.push_back(getEncodedLinkage(F));
1414     Vals.push_back(VE.getAttributeListID(F.getAttributes()));
1415     Vals.push_back(getEncodedAlign(F.getAlign()));
1416     Vals.push_back(F.hasSection() ? SectionMap[std::string(F.getSection())]
1417                                   : 0);
1418     Vals.push_back(getEncodedVisibility(F));
1419     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
1420     Vals.push_back(getEncodedUnnamedAddr(F));
1421     Vals.push_back(F.hasPrologueData() ? (VE.getValueID(F.getPrologueData()) + 1)
1422                                        : 0);
1423     Vals.push_back(getEncodedDLLStorageClass(F));
1424     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
1425     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
1426                                      : 0);
1427     Vals.push_back(
1428         F.hasPersonalityFn() ? (VE.getValueID(F.getPersonalityFn()) + 1) : 0);
1429 
1430     Vals.push_back(F.isDSOLocal());
1431     Vals.push_back(F.getAddressSpace());
1432     Vals.push_back(addToStrtab(F.getPartition()));
1433     Vals.push_back(F.getPartition().size());
1434 
1435     unsigned AbbrevToUse = 0;
1436     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
1437     Vals.clear();
1438   }
1439 
1440   // Emit the alias information.
1441   for (const GlobalAlias &A : M.aliases()) {
1442     // ALIAS: [strtab offset, strtab size, alias type, aliasee val#, linkage,
1443     //         visibility, dllstorageclass, threadlocal, unnamed_addr,
1444     //         DSO_Local]
1445     Vals.push_back(addToStrtab(A.getName()));
1446     Vals.push_back(A.getName().size());
1447     Vals.push_back(VE.getTypeID(A.getValueType()));
1448     Vals.push_back(A.getType()->getAddressSpace());
1449     Vals.push_back(VE.getValueID(A.getAliasee()));
1450     Vals.push_back(getEncodedLinkage(A));
1451     Vals.push_back(getEncodedVisibility(A));
1452     Vals.push_back(getEncodedDLLStorageClass(A));
1453     Vals.push_back(getEncodedThreadLocalMode(A));
1454     Vals.push_back(getEncodedUnnamedAddr(A));
1455     Vals.push_back(A.isDSOLocal());
1456     Vals.push_back(addToStrtab(A.getPartition()));
1457     Vals.push_back(A.getPartition().size());
1458 
1459     unsigned AbbrevToUse = 0;
1460     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
1461     Vals.clear();
1462   }
1463 
1464   // Emit the ifunc information.
1465   for (const GlobalIFunc &I : M.ifuncs()) {
1466     // IFUNC: [strtab offset, strtab size, ifunc type, address space, resolver
1467     //         val#, linkage, visibility, DSO_Local]
1468     Vals.push_back(addToStrtab(I.getName()));
1469     Vals.push_back(I.getName().size());
1470     Vals.push_back(VE.getTypeID(I.getValueType()));
1471     Vals.push_back(I.getType()->getAddressSpace());
1472     Vals.push_back(VE.getValueID(I.getResolver()));
1473     Vals.push_back(getEncodedLinkage(I));
1474     Vals.push_back(getEncodedVisibility(I));
1475     Vals.push_back(I.isDSOLocal());
1476     Vals.push_back(addToStrtab(I.getPartition()));
1477     Vals.push_back(I.getPartition().size());
1478     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
1479     Vals.clear();
1480   }
1481 
1482   writeValueSymbolTableForwardDecl();
1483 }
1484 
1485 static uint64_t getOptimizationFlags(const Value *V) {
1486   uint64_t Flags = 0;
1487 
1488   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
1489     if (OBO->hasNoSignedWrap())
1490       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
1491     if (OBO->hasNoUnsignedWrap())
1492       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
1493   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
1494     if (PEO->isExact())
1495       Flags |= 1 << bitc::PEO_EXACT;
1496   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
1497     if (FPMO->hasAllowReassoc())
1498       Flags |= bitc::AllowReassoc;
1499     if (FPMO->hasNoNaNs())
1500       Flags |= bitc::NoNaNs;
1501     if (FPMO->hasNoInfs())
1502       Flags |= bitc::NoInfs;
1503     if (FPMO->hasNoSignedZeros())
1504       Flags |= bitc::NoSignedZeros;
1505     if (FPMO->hasAllowReciprocal())
1506       Flags |= bitc::AllowReciprocal;
1507     if (FPMO->hasAllowContract())
1508       Flags |= bitc::AllowContract;
1509     if (FPMO->hasApproxFunc())
1510       Flags |= bitc::ApproxFunc;
1511   }
1512 
1513   return Flags;
1514 }
1515 
1516 void ModuleBitcodeWriter::writeValueAsMetadata(
1517     const ValueAsMetadata *MD, SmallVectorImpl<uint64_t> &Record) {
1518   // Mimic an MDNode with a value as one operand.
1519   Value *V = MD->getValue();
1520   Record.push_back(VE.getTypeID(V->getType()));
1521   Record.push_back(VE.getValueID(V));
1522   Stream.EmitRecord(bitc::METADATA_VALUE, Record, 0);
1523   Record.clear();
1524 }
1525 
1526 void ModuleBitcodeWriter::writeMDTuple(const MDTuple *N,
1527                                        SmallVectorImpl<uint64_t> &Record,
1528                                        unsigned Abbrev) {
1529   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
1530     Metadata *MD = N->getOperand(i);
1531     assert(!(MD && isa<LocalAsMetadata>(MD)) &&
1532            "Unexpected function-local metadata");
1533     Record.push_back(VE.getMetadataOrNullID(MD));
1534   }
1535   Stream.EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
1536                                     : bitc::METADATA_NODE,
1537                     Record, Abbrev);
1538   Record.clear();
1539 }
1540 
1541 unsigned ModuleBitcodeWriter::createDILocationAbbrev() {
1542   // Assume the column is usually under 128, and always output the inlined-at
1543   // location (it's never more expensive than building an array size 1).
1544   auto Abbv = std::make_shared<BitCodeAbbrev>();
1545   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
1546   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1547   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1548   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1549   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1550   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1551   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1552   return Stream.EmitAbbrev(std::move(Abbv));
1553 }
1554 
1555 void ModuleBitcodeWriter::writeDILocation(const DILocation *N,
1556                                           SmallVectorImpl<uint64_t> &Record,
1557                                           unsigned &Abbrev) {
1558   if (!Abbrev)
1559     Abbrev = createDILocationAbbrev();
1560 
1561   Record.push_back(N->isDistinct());
1562   Record.push_back(N->getLine());
1563   Record.push_back(N->getColumn());
1564   Record.push_back(VE.getMetadataID(N->getScope()));
1565   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
1566   Record.push_back(N->isImplicitCode());
1567 
1568   Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
1569   Record.clear();
1570 }
1571 
1572 unsigned ModuleBitcodeWriter::createGenericDINodeAbbrev() {
1573   // Assume the column is usually under 128, and always output the inlined-at
1574   // location (it's never more expensive than building an array size 1).
1575   auto Abbv = std::make_shared<BitCodeAbbrev>();
1576   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
1577   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1578   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1579   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1580   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1581   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1582   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1583   return Stream.EmitAbbrev(std::move(Abbv));
1584 }
1585 
1586 void ModuleBitcodeWriter::writeGenericDINode(const GenericDINode *N,
1587                                              SmallVectorImpl<uint64_t> &Record,
1588                                              unsigned &Abbrev) {
1589   if (!Abbrev)
1590     Abbrev = createGenericDINodeAbbrev();
1591 
1592   Record.push_back(N->isDistinct());
1593   Record.push_back(N->getTag());
1594   Record.push_back(0); // Per-tag version field; unused for now.
1595 
1596   for (auto &I : N->operands())
1597     Record.push_back(VE.getMetadataOrNullID(I));
1598 
1599   Stream.EmitRecord(bitc::METADATA_GENERIC_DEBUG, Record, Abbrev);
1600   Record.clear();
1601 }
1602 
1603 void ModuleBitcodeWriter::writeDISubrange(const DISubrange *N,
1604                                           SmallVectorImpl<uint64_t> &Record,
1605                                           unsigned Abbrev) {
1606   const uint64_t Version = 2 << 1;
1607   Record.push_back((uint64_t)N->isDistinct() | Version);
1608   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1609   Record.push_back(VE.getMetadataOrNullID(N->getRawLowerBound()));
1610   Record.push_back(VE.getMetadataOrNullID(N->getRawUpperBound()));
1611   Record.push_back(VE.getMetadataOrNullID(N->getRawStride()));
1612 
1613   Stream.EmitRecord(bitc::METADATA_SUBRANGE, Record, Abbrev);
1614   Record.clear();
1615 }
1616 
1617 void ModuleBitcodeWriter::writeDIGenericSubrange(
1618     const DIGenericSubrange *N, SmallVectorImpl<uint64_t> &Record,
1619     unsigned Abbrev) {
1620   Record.push_back((uint64_t)N->isDistinct());
1621   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1622   Record.push_back(VE.getMetadataOrNullID(N->getRawLowerBound()));
1623   Record.push_back(VE.getMetadataOrNullID(N->getRawUpperBound()));
1624   Record.push_back(VE.getMetadataOrNullID(N->getRawStride()));
1625 
1626   Stream.EmitRecord(bitc::METADATA_GENERIC_SUBRANGE, Record, Abbrev);
1627   Record.clear();
1628 }
1629 
1630 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
1631   if ((int64_t)V >= 0)
1632     Vals.push_back(V << 1);
1633   else
1634     Vals.push_back((-V << 1) | 1);
1635 }
1636 
1637 static void emitWideAPInt(SmallVectorImpl<uint64_t> &Vals, const APInt &A) {
1638   // We have an arbitrary precision integer value to write whose
1639   // bit width is > 64. However, in canonical unsigned integer
1640   // format it is likely that the high bits are going to be zero.
1641   // So, we only write the number of active words.
1642   unsigned NumWords = A.getActiveWords();
1643   const uint64_t *RawData = A.getRawData();
1644   for (unsigned i = 0; i < NumWords; i++)
1645     emitSignedInt64(Vals, RawData[i]);
1646 }
1647 
1648 void ModuleBitcodeWriter::writeDIEnumerator(const DIEnumerator *N,
1649                                             SmallVectorImpl<uint64_t> &Record,
1650                                             unsigned Abbrev) {
1651   const uint64_t IsBigInt = 1 << 2;
1652   Record.push_back(IsBigInt | (N->isUnsigned() << 1) | N->isDistinct());
1653   Record.push_back(N->getValue().getBitWidth());
1654   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1655   emitWideAPInt(Record, N->getValue());
1656 
1657   Stream.EmitRecord(bitc::METADATA_ENUMERATOR, Record, Abbrev);
1658   Record.clear();
1659 }
1660 
1661 void ModuleBitcodeWriter::writeDIBasicType(const DIBasicType *N,
1662                                            SmallVectorImpl<uint64_t> &Record,
1663                                            unsigned Abbrev) {
1664   Record.push_back(N->isDistinct());
1665   Record.push_back(N->getTag());
1666   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1667   Record.push_back(N->getSizeInBits());
1668   Record.push_back(N->getAlignInBits());
1669   Record.push_back(N->getEncoding());
1670   Record.push_back(N->getFlags());
1671 
1672   Stream.EmitRecord(bitc::METADATA_BASIC_TYPE, Record, Abbrev);
1673   Record.clear();
1674 }
1675 
1676 void ModuleBitcodeWriter::writeDIStringType(const DIStringType *N,
1677                                             SmallVectorImpl<uint64_t> &Record,
1678                                             unsigned Abbrev) {
1679   Record.push_back(N->isDistinct());
1680   Record.push_back(N->getTag());
1681   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1682   Record.push_back(VE.getMetadataOrNullID(N->getStringLength()));
1683   Record.push_back(VE.getMetadataOrNullID(N->getStringLengthExp()));
1684   Record.push_back(VE.getMetadataOrNullID(N->getStringLocationExp()));
1685   Record.push_back(N->getSizeInBits());
1686   Record.push_back(N->getAlignInBits());
1687   Record.push_back(N->getEncoding());
1688 
1689   Stream.EmitRecord(bitc::METADATA_STRING_TYPE, Record, Abbrev);
1690   Record.clear();
1691 }
1692 
1693 void ModuleBitcodeWriter::writeDIDerivedType(const DIDerivedType *N,
1694                                              SmallVectorImpl<uint64_t> &Record,
1695                                              unsigned Abbrev) {
1696   Record.push_back(N->isDistinct());
1697   Record.push_back(N->getTag());
1698   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1699   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1700   Record.push_back(N->getLine());
1701   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1702   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1703   Record.push_back(N->getSizeInBits());
1704   Record.push_back(N->getAlignInBits());
1705   Record.push_back(N->getOffsetInBits());
1706   Record.push_back(N->getFlags());
1707   Record.push_back(VE.getMetadataOrNullID(N->getExtraData()));
1708 
1709   // DWARF address space is encoded as N->getDWARFAddressSpace() + 1. 0 means
1710   // that there is no DWARF address space associated with DIDerivedType.
1711   if (const auto &DWARFAddressSpace = N->getDWARFAddressSpace())
1712     Record.push_back(*DWARFAddressSpace + 1);
1713   else
1714     Record.push_back(0);
1715 
1716   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1717 
1718   Stream.EmitRecord(bitc::METADATA_DERIVED_TYPE, Record, Abbrev);
1719   Record.clear();
1720 }
1721 
1722 void ModuleBitcodeWriter::writeDICompositeType(
1723     const DICompositeType *N, SmallVectorImpl<uint64_t> &Record,
1724     unsigned Abbrev) {
1725   const unsigned IsNotUsedInOldTypeRef = 0x2;
1726   Record.push_back(IsNotUsedInOldTypeRef | (unsigned)N->isDistinct());
1727   Record.push_back(N->getTag());
1728   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1729   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1730   Record.push_back(N->getLine());
1731   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1732   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1733   Record.push_back(N->getSizeInBits());
1734   Record.push_back(N->getAlignInBits());
1735   Record.push_back(N->getOffsetInBits());
1736   Record.push_back(N->getFlags());
1737   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1738   Record.push_back(N->getRuntimeLang());
1739   Record.push_back(VE.getMetadataOrNullID(N->getVTableHolder()));
1740   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1741   Record.push_back(VE.getMetadataOrNullID(N->getRawIdentifier()));
1742   Record.push_back(VE.getMetadataOrNullID(N->getDiscriminator()));
1743   Record.push_back(VE.getMetadataOrNullID(N->getRawDataLocation()));
1744   Record.push_back(VE.getMetadataOrNullID(N->getRawAssociated()));
1745   Record.push_back(VE.getMetadataOrNullID(N->getRawAllocated()));
1746   Record.push_back(VE.getMetadataOrNullID(N->getRawRank()));
1747   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1748 
1749   Stream.EmitRecord(bitc::METADATA_COMPOSITE_TYPE, Record, Abbrev);
1750   Record.clear();
1751 }
1752 
1753 void ModuleBitcodeWriter::writeDISubroutineType(
1754     const DISubroutineType *N, SmallVectorImpl<uint64_t> &Record,
1755     unsigned Abbrev) {
1756   const unsigned HasNoOldTypeRefs = 0x2;
1757   Record.push_back(HasNoOldTypeRefs | (unsigned)N->isDistinct());
1758   Record.push_back(N->getFlags());
1759   Record.push_back(VE.getMetadataOrNullID(N->getTypeArray().get()));
1760   Record.push_back(N->getCC());
1761 
1762   Stream.EmitRecord(bitc::METADATA_SUBROUTINE_TYPE, Record, Abbrev);
1763   Record.clear();
1764 }
1765 
1766 void ModuleBitcodeWriter::writeDIFile(const DIFile *N,
1767                                       SmallVectorImpl<uint64_t> &Record,
1768                                       unsigned Abbrev) {
1769   Record.push_back(N->isDistinct());
1770   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
1771   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
1772   if (N->getRawChecksum()) {
1773     Record.push_back(N->getRawChecksum()->Kind);
1774     Record.push_back(VE.getMetadataOrNullID(N->getRawChecksum()->Value));
1775   } else {
1776     // Maintain backwards compatibility with the old internal representation of
1777     // CSK_None in ChecksumKind by writing nulls here when Checksum is None.
1778     Record.push_back(0);
1779     Record.push_back(VE.getMetadataOrNullID(nullptr));
1780   }
1781   auto Source = N->getRawSource();
1782   if (Source)
1783     Record.push_back(VE.getMetadataOrNullID(*Source));
1784 
1785   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
1786   Record.clear();
1787 }
1788 
1789 void ModuleBitcodeWriter::writeDICompileUnit(const DICompileUnit *N,
1790                                              SmallVectorImpl<uint64_t> &Record,
1791                                              unsigned Abbrev) {
1792   assert(N->isDistinct() && "Expected distinct compile units");
1793   Record.push_back(/* IsDistinct */ true);
1794   Record.push_back(N->getSourceLanguage());
1795   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1796   Record.push_back(VE.getMetadataOrNullID(N->getRawProducer()));
1797   Record.push_back(N->isOptimized());
1798   Record.push_back(VE.getMetadataOrNullID(N->getRawFlags()));
1799   Record.push_back(N->getRuntimeVersion());
1800   Record.push_back(VE.getMetadataOrNullID(N->getRawSplitDebugFilename()));
1801   Record.push_back(N->getEmissionKind());
1802   Record.push_back(VE.getMetadataOrNullID(N->getEnumTypes().get()));
1803   Record.push_back(VE.getMetadataOrNullID(N->getRetainedTypes().get()));
1804   Record.push_back(/* subprograms */ 0);
1805   Record.push_back(VE.getMetadataOrNullID(N->getGlobalVariables().get()));
1806   Record.push_back(VE.getMetadataOrNullID(N->getImportedEntities().get()));
1807   Record.push_back(N->getDWOId());
1808   Record.push_back(VE.getMetadataOrNullID(N->getMacros().get()));
1809   Record.push_back(N->getSplitDebugInlining());
1810   Record.push_back(N->getDebugInfoForProfiling());
1811   Record.push_back((unsigned)N->getNameTableKind());
1812   Record.push_back(N->getRangesBaseAddress());
1813   Record.push_back(VE.getMetadataOrNullID(N->getRawSysRoot()));
1814   Record.push_back(VE.getMetadataOrNullID(N->getRawSDK()));
1815 
1816   Stream.EmitRecord(bitc::METADATA_COMPILE_UNIT, Record, Abbrev);
1817   Record.clear();
1818 }
1819 
1820 void ModuleBitcodeWriter::writeDISubprogram(const DISubprogram *N,
1821                                             SmallVectorImpl<uint64_t> &Record,
1822                                             unsigned Abbrev) {
1823   const uint64_t HasUnitFlag = 1 << 1;
1824   const uint64_t HasSPFlagsFlag = 1 << 2;
1825   Record.push_back(uint64_t(N->isDistinct()) | HasUnitFlag | HasSPFlagsFlag);
1826   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1827   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1828   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1829   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1830   Record.push_back(N->getLine());
1831   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1832   Record.push_back(N->getScopeLine());
1833   Record.push_back(VE.getMetadataOrNullID(N->getContainingType()));
1834   Record.push_back(N->getSPFlags());
1835   Record.push_back(N->getVirtualIndex());
1836   Record.push_back(N->getFlags());
1837   Record.push_back(VE.getMetadataOrNullID(N->getRawUnit()));
1838   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1839   Record.push_back(VE.getMetadataOrNullID(N->getDeclaration()));
1840   Record.push_back(VE.getMetadataOrNullID(N->getRetainedNodes().get()));
1841   Record.push_back(N->getThisAdjustment());
1842   Record.push_back(VE.getMetadataOrNullID(N->getThrownTypes().get()));
1843   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1844   Record.push_back(VE.getMetadataOrNullID(N->getRawTargetFuncName()));
1845 
1846   Stream.EmitRecord(bitc::METADATA_SUBPROGRAM, Record, Abbrev);
1847   Record.clear();
1848 }
1849 
1850 void ModuleBitcodeWriter::writeDILexicalBlock(const DILexicalBlock *N,
1851                                               SmallVectorImpl<uint64_t> &Record,
1852                                               unsigned Abbrev) {
1853   Record.push_back(N->isDistinct());
1854   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1855   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1856   Record.push_back(N->getLine());
1857   Record.push_back(N->getColumn());
1858 
1859   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK, Record, Abbrev);
1860   Record.clear();
1861 }
1862 
1863 void ModuleBitcodeWriter::writeDILexicalBlockFile(
1864     const DILexicalBlockFile *N, 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->getFile()));
1869   Record.push_back(N->getDiscriminator());
1870 
1871   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK_FILE, Record, Abbrev);
1872   Record.clear();
1873 }
1874 
1875 void ModuleBitcodeWriter::writeDICommonBlock(const DICommonBlock *N,
1876                                              SmallVectorImpl<uint64_t> &Record,
1877                                              unsigned Abbrev) {
1878   Record.push_back(N->isDistinct());
1879   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1880   Record.push_back(VE.getMetadataOrNullID(N->getDecl()));
1881   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1882   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1883   Record.push_back(N->getLineNo());
1884 
1885   Stream.EmitRecord(bitc::METADATA_COMMON_BLOCK, Record, Abbrev);
1886   Record.clear();
1887 }
1888 
1889 void ModuleBitcodeWriter::writeDINamespace(const DINamespace *N,
1890                                            SmallVectorImpl<uint64_t> &Record,
1891                                            unsigned Abbrev) {
1892   Record.push_back(N->isDistinct() | N->getExportSymbols() << 1);
1893   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1894   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1895 
1896   Stream.EmitRecord(bitc::METADATA_NAMESPACE, Record, Abbrev);
1897   Record.clear();
1898 }
1899 
1900 void ModuleBitcodeWriter::writeDIMacro(const DIMacro *N,
1901                                        SmallVectorImpl<uint64_t> &Record,
1902                                        unsigned Abbrev) {
1903   Record.push_back(N->isDistinct());
1904   Record.push_back(N->getMacinfoType());
1905   Record.push_back(N->getLine());
1906   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1907   Record.push_back(VE.getMetadataOrNullID(N->getRawValue()));
1908 
1909   Stream.EmitRecord(bitc::METADATA_MACRO, Record, Abbrev);
1910   Record.clear();
1911 }
1912 
1913 void ModuleBitcodeWriter::writeDIMacroFile(const DIMacroFile *N,
1914                                            SmallVectorImpl<uint64_t> &Record,
1915                                            unsigned Abbrev) {
1916   Record.push_back(N->isDistinct());
1917   Record.push_back(N->getMacinfoType());
1918   Record.push_back(N->getLine());
1919   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1920   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1921 
1922   Stream.EmitRecord(bitc::METADATA_MACRO_FILE, Record, Abbrev);
1923   Record.clear();
1924 }
1925 
1926 void ModuleBitcodeWriter::writeDIArgList(const DIArgList *N,
1927                                          SmallVectorImpl<uint64_t> &Record,
1928                                          unsigned Abbrev) {
1929   Record.reserve(N->getArgs().size());
1930   for (ValueAsMetadata *MD : N->getArgs())
1931     Record.push_back(VE.getMetadataID(MD));
1932 
1933   Stream.EmitRecord(bitc::METADATA_ARG_LIST, Record, Abbrev);
1934   Record.clear();
1935 }
1936 
1937 void ModuleBitcodeWriter::writeDIModule(const DIModule *N,
1938                                         SmallVectorImpl<uint64_t> &Record,
1939                                         unsigned Abbrev) {
1940   Record.push_back(N->isDistinct());
1941   for (auto &I : N->operands())
1942     Record.push_back(VE.getMetadataOrNullID(I));
1943   Record.push_back(N->getLineNo());
1944   Record.push_back(N->getIsDecl());
1945 
1946   Stream.EmitRecord(bitc::METADATA_MODULE, Record, Abbrev);
1947   Record.clear();
1948 }
1949 
1950 void ModuleBitcodeWriter::writeDITemplateTypeParameter(
1951     const DITemplateTypeParameter *N, SmallVectorImpl<uint64_t> &Record,
1952     unsigned Abbrev) {
1953   Record.push_back(N->isDistinct());
1954   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1955   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1956   Record.push_back(N->isDefault());
1957 
1958   Stream.EmitRecord(bitc::METADATA_TEMPLATE_TYPE, Record, Abbrev);
1959   Record.clear();
1960 }
1961 
1962 void ModuleBitcodeWriter::writeDITemplateValueParameter(
1963     const DITemplateValueParameter *N, SmallVectorImpl<uint64_t> &Record,
1964     unsigned Abbrev) {
1965   Record.push_back(N->isDistinct());
1966   Record.push_back(N->getTag());
1967   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1968   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1969   Record.push_back(N->isDefault());
1970   Record.push_back(VE.getMetadataOrNullID(N->getValue()));
1971 
1972   Stream.EmitRecord(bitc::METADATA_TEMPLATE_VALUE, Record, Abbrev);
1973   Record.clear();
1974 }
1975 
1976 void ModuleBitcodeWriter::writeDIGlobalVariable(
1977     const DIGlobalVariable *N, SmallVectorImpl<uint64_t> &Record,
1978     unsigned Abbrev) {
1979   const uint64_t Version = 2 << 1;
1980   Record.push_back((uint64_t)N->isDistinct() | Version);
1981   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1982   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1983   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1984   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1985   Record.push_back(N->getLine());
1986   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1987   Record.push_back(N->isLocalToUnit());
1988   Record.push_back(N->isDefinition());
1989   Record.push_back(VE.getMetadataOrNullID(N->getStaticDataMemberDeclaration()));
1990   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams()));
1991   Record.push_back(N->getAlignInBits());
1992   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1993 
1994   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR, Record, Abbrev);
1995   Record.clear();
1996 }
1997 
1998 void ModuleBitcodeWriter::writeDILocalVariable(
1999     const DILocalVariable *N, SmallVectorImpl<uint64_t> &Record,
2000     unsigned Abbrev) {
2001   // In order to support all possible bitcode formats in BitcodeReader we need
2002   // to distinguish the following cases:
2003   // 1) Record has no artificial tag (Record[1]),
2004   //   has no obsolete inlinedAt field (Record[9]).
2005   //   In this case Record size will be 8, HasAlignment flag is false.
2006   // 2) Record has artificial tag (Record[1]),
2007   //   has no obsolete inlignedAt field (Record[9]).
2008   //   In this case Record size will be 9, HasAlignment flag is false.
2009   // 3) Record has both artificial tag (Record[1]) and
2010   //   obsolete inlignedAt field (Record[9]).
2011   //   In this case Record size will be 10, HasAlignment flag is false.
2012   // 4) Record has neither artificial tag, nor inlignedAt field, but
2013   //   HasAlignment flag is true and Record[8] contains alignment value.
2014   const uint64_t HasAlignmentFlag = 1 << 1;
2015   Record.push_back((uint64_t)N->isDistinct() | HasAlignmentFlag);
2016   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2017   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2018   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2019   Record.push_back(N->getLine());
2020   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2021   Record.push_back(N->getArg());
2022   Record.push_back(N->getFlags());
2023   Record.push_back(N->getAlignInBits());
2024   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
2025 
2026   Stream.EmitRecord(bitc::METADATA_LOCAL_VAR, Record, Abbrev);
2027   Record.clear();
2028 }
2029 
2030 void ModuleBitcodeWriter::writeDILabel(
2031     const DILabel *N, SmallVectorImpl<uint64_t> &Record,
2032     unsigned Abbrev) {
2033   Record.push_back((uint64_t)N->isDistinct());
2034   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2035   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2036   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2037   Record.push_back(N->getLine());
2038 
2039   Stream.EmitRecord(bitc::METADATA_LABEL, Record, Abbrev);
2040   Record.clear();
2041 }
2042 
2043 void ModuleBitcodeWriter::writeDIExpression(const DIExpression *N,
2044                                             SmallVectorImpl<uint64_t> &Record,
2045                                             unsigned Abbrev) {
2046   Record.reserve(N->getElements().size() + 1);
2047   const uint64_t Version = 3 << 1;
2048   Record.push_back((uint64_t)N->isDistinct() | Version);
2049   Record.append(N->elements_begin(), N->elements_end());
2050 
2051   Stream.EmitRecord(bitc::METADATA_EXPRESSION, Record, Abbrev);
2052   Record.clear();
2053 }
2054 
2055 void ModuleBitcodeWriter::writeDIGlobalVariableExpression(
2056     const DIGlobalVariableExpression *N, SmallVectorImpl<uint64_t> &Record,
2057     unsigned Abbrev) {
2058   Record.push_back(N->isDistinct());
2059   Record.push_back(VE.getMetadataOrNullID(N->getVariable()));
2060   Record.push_back(VE.getMetadataOrNullID(N->getExpression()));
2061 
2062   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR_EXPR, Record, Abbrev);
2063   Record.clear();
2064 }
2065 
2066 void ModuleBitcodeWriter::writeDIObjCProperty(const DIObjCProperty *N,
2067                                               SmallVectorImpl<uint64_t> &Record,
2068                                               unsigned Abbrev) {
2069   Record.push_back(N->isDistinct());
2070   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2071   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2072   Record.push_back(N->getLine());
2073   Record.push_back(VE.getMetadataOrNullID(N->getRawSetterName()));
2074   Record.push_back(VE.getMetadataOrNullID(N->getRawGetterName()));
2075   Record.push_back(N->getAttributes());
2076   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2077 
2078   Stream.EmitRecord(bitc::METADATA_OBJC_PROPERTY, Record, Abbrev);
2079   Record.clear();
2080 }
2081 
2082 void ModuleBitcodeWriter::writeDIImportedEntity(
2083     const DIImportedEntity *N, SmallVectorImpl<uint64_t> &Record,
2084     unsigned Abbrev) {
2085   Record.push_back(N->isDistinct());
2086   Record.push_back(N->getTag());
2087   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2088   Record.push_back(VE.getMetadataOrNullID(N->getEntity()));
2089   Record.push_back(N->getLine());
2090   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2091   Record.push_back(VE.getMetadataOrNullID(N->getRawFile()));
2092   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
2093 
2094   Stream.EmitRecord(bitc::METADATA_IMPORTED_ENTITY, Record, Abbrev);
2095   Record.clear();
2096 }
2097 
2098 unsigned ModuleBitcodeWriter::createNamedMetadataAbbrev() {
2099   auto Abbv = std::make_shared<BitCodeAbbrev>();
2100   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
2101   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2102   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2103   return Stream.EmitAbbrev(std::move(Abbv));
2104 }
2105 
2106 void ModuleBitcodeWriter::writeNamedMetadata(
2107     SmallVectorImpl<uint64_t> &Record) {
2108   if (M.named_metadata_empty())
2109     return;
2110 
2111   unsigned Abbrev = createNamedMetadataAbbrev();
2112   for (const NamedMDNode &NMD : M.named_metadata()) {
2113     // Write name.
2114     StringRef Str = NMD.getName();
2115     Record.append(Str.bytes_begin(), Str.bytes_end());
2116     Stream.EmitRecord(bitc::METADATA_NAME, Record, Abbrev);
2117     Record.clear();
2118 
2119     // Write named metadata operands.
2120     for (const MDNode *N : NMD.operands())
2121       Record.push_back(VE.getMetadataID(N));
2122     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
2123     Record.clear();
2124   }
2125 }
2126 
2127 unsigned ModuleBitcodeWriter::createMetadataStringsAbbrev() {
2128   auto Abbv = std::make_shared<BitCodeAbbrev>();
2129   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRINGS));
2130   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // # of strings
2131   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // offset to chars
2132   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
2133   return Stream.EmitAbbrev(std::move(Abbv));
2134 }
2135 
2136 /// Write out a record for MDString.
2137 ///
2138 /// All the metadata strings in a metadata block are emitted in a single
2139 /// record.  The sizes and strings themselves are shoved into a blob.
2140 void ModuleBitcodeWriter::writeMetadataStrings(
2141     ArrayRef<const Metadata *> Strings, SmallVectorImpl<uint64_t> &Record) {
2142   if (Strings.empty())
2143     return;
2144 
2145   // Start the record with the number of strings.
2146   Record.push_back(bitc::METADATA_STRINGS);
2147   Record.push_back(Strings.size());
2148 
2149   // Emit the sizes of the strings in the blob.
2150   SmallString<256> Blob;
2151   {
2152     BitstreamWriter W(Blob);
2153     for (const Metadata *MD : Strings)
2154       W.EmitVBR(cast<MDString>(MD)->getLength(), 6);
2155     W.FlushToWord();
2156   }
2157 
2158   // Add the offset to the strings to the record.
2159   Record.push_back(Blob.size());
2160 
2161   // Add the strings to the blob.
2162   for (const Metadata *MD : Strings)
2163     Blob.append(cast<MDString>(MD)->getString());
2164 
2165   // Emit the final record.
2166   Stream.EmitRecordWithBlob(createMetadataStringsAbbrev(), Record, Blob);
2167   Record.clear();
2168 }
2169 
2170 // Generates an enum to use as an index in the Abbrev array of Metadata record.
2171 enum MetadataAbbrev : unsigned {
2172 #define HANDLE_MDNODE_LEAF(CLASS) CLASS##AbbrevID,
2173 #include "llvm/IR/Metadata.def"
2174   LastPlusOne
2175 };
2176 
2177 void ModuleBitcodeWriter::writeMetadataRecords(
2178     ArrayRef<const Metadata *> MDs, SmallVectorImpl<uint64_t> &Record,
2179     std::vector<unsigned> *MDAbbrevs, std::vector<uint64_t> *IndexPos) {
2180   if (MDs.empty())
2181     return;
2182 
2183   // Initialize MDNode abbreviations.
2184 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
2185 #include "llvm/IR/Metadata.def"
2186 
2187   for (const Metadata *MD : MDs) {
2188     if (IndexPos)
2189       IndexPos->push_back(Stream.GetCurrentBitNo());
2190     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
2191       assert(N->isResolved() && "Expected forward references to be resolved");
2192 
2193       switch (N->getMetadataID()) {
2194       default:
2195         llvm_unreachable("Invalid MDNode subclass");
2196 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
2197   case Metadata::CLASS##Kind:                                                  \
2198     if (MDAbbrevs)                                                             \
2199       write##CLASS(cast<CLASS>(N), Record,                                     \
2200                    (*MDAbbrevs)[MetadataAbbrev::CLASS##AbbrevID]);             \
2201     else                                                                       \
2202       write##CLASS(cast<CLASS>(N), Record, CLASS##Abbrev);                     \
2203     continue;
2204 #include "llvm/IR/Metadata.def"
2205       }
2206     }
2207     writeValueAsMetadata(cast<ValueAsMetadata>(MD), Record);
2208   }
2209 }
2210 
2211 void ModuleBitcodeWriter::writeModuleMetadata() {
2212   if (!VE.hasMDs() && M.named_metadata_empty())
2213     return;
2214 
2215   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 4);
2216   SmallVector<uint64_t, 64> Record;
2217 
2218   // Emit all abbrevs upfront, so that the reader can jump in the middle of the
2219   // block and load any metadata.
2220   std::vector<unsigned> MDAbbrevs;
2221 
2222   MDAbbrevs.resize(MetadataAbbrev::LastPlusOne);
2223   MDAbbrevs[MetadataAbbrev::DILocationAbbrevID] = createDILocationAbbrev();
2224   MDAbbrevs[MetadataAbbrev::GenericDINodeAbbrevID] =
2225       createGenericDINodeAbbrev();
2226 
2227   auto Abbv = std::make_shared<BitCodeAbbrev>();
2228   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX_OFFSET));
2229   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2230   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2231   unsigned OffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2232 
2233   Abbv = std::make_shared<BitCodeAbbrev>();
2234   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX));
2235   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2236   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2237   unsigned IndexAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2238 
2239   // Emit MDStrings together upfront.
2240   writeMetadataStrings(VE.getMDStrings(), Record);
2241 
2242   // We only emit an index for the metadata record if we have more than a given
2243   // (naive) threshold of metadatas, otherwise it is not worth it.
2244   if (VE.getNonMDStrings().size() > IndexThreshold) {
2245     // Write a placeholder value in for the offset of the metadata index,
2246     // which is written after the records, so that it can include
2247     // the offset of each entry. The placeholder offset will be
2248     // updated after all records are emitted.
2249     uint64_t Vals[] = {0, 0};
2250     Stream.EmitRecord(bitc::METADATA_INDEX_OFFSET, Vals, OffsetAbbrev);
2251   }
2252 
2253   // Compute and save the bit offset to the current position, which will be
2254   // patched when we emit the index later. We can simply subtract the 64-bit
2255   // fixed size from the current bit number to get the location to backpatch.
2256   uint64_t IndexOffsetRecordBitPos = Stream.GetCurrentBitNo();
2257 
2258   // This index will contain the bitpos for each individual record.
2259   std::vector<uint64_t> IndexPos;
2260   IndexPos.reserve(VE.getNonMDStrings().size());
2261 
2262   // Write all the records
2263   writeMetadataRecords(VE.getNonMDStrings(), Record, &MDAbbrevs, &IndexPos);
2264 
2265   if (VE.getNonMDStrings().size() > IndexThreshold) {
2266     // Now that we have emitted all the records we will emit the index. But
2267     // first
2268     // backpatch the forward reference so that the reader can skip the records
2269     // efficiently.
2270     Stream.BackpatchWord64(IndexOffsetRecordBitPos - 64,
2271                            Stream.GetCurrentBitNo() - IndexOffsetRecordBitPos);
2272 
2273     // Delta encode the index.
2274     uint64_t PreviousValue = IndexOffsetRecordBitPos;
2275     for (auto &Elt : IndexPos) {
2276       auto EltDelta = Elt - PreviousValue;
2277       PreviousValue = Elt;
2278       Elt = EltDelta;
2279     }
2280     // Emit the index record.
2281     Stream.EmitRecord(bitc::METADATA_INDEX, IndexPos, IndexAbbrev);
2282     IndexPos.clear();
2283   }
2284 
2285   // Write the named metadata now.
2286   writeNamedMetadata(Record);
2287 
2288   auto AddDeclAttachedMetadata = [&](const GlobalObject &GO) {
2289     SmallVector<uint64_t, 4> Record;
2290     Record.push_back(VE.getValueID(&GO));
2291     pushGlobalMetadataAttachment(Record, GO);
2292     Stream.EmitRecord(bitc::METADATA_GLOBAL_DECL_ATTACHMENT, Record);
2293   };
2294   for (const Function &F : M)
2295     if (F.isDeclaration() && F.hasMetadata())
2296       AddDeclAttachedMetadata(F);
2297   // FIXME: Only store metadata for declarations here, and move data for global
2298   // variable definitions to a separate block (PR28134).
2299   for (const GlobalVariable &GV : M.globals())
2300     if (GV.hasMetadata())
2301       AddDeclAttachedMetadata(GV);
2302 
2303   Stream.ExitBlock();
2304 }
2305 
2306 void ModuleBitcodeWriter::writeFunctionMetadata(const Function &F) {
2307   if (!VE.hasMDs())
2308     return;
2309 
2310   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
2311   SmallVector<uint64_t, 64> Record;
2312   writeMetadataStrings(VE.getMDStrings(), Record);
2313   writeMetadataRecords(VE.getNonMDStrings(), Record);
2314   Stream.ExitBlock();
2315 }
2316 
2317 void ModuleBitcodeWriter::pushGlobalMetadataAttachment(
2318     SmallVectorImpl<uint64_t> &Record, const GlobalObject &GO) {
2319   // [n x [id, mdnode]]
2320   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2321   GO.getAllMetadata(MDs);
2322   for (const auto &I : MDs) {
2323     Record.push_back(I.first);
2324     Record.push_back(VE.getMetadataID(I.second));
2325   }
2326 }
2327 
2328 void ModuleBitcodeWriter::writeFunctionMetadataAttachment(const Function &F) {
2329   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
2330 
2331   SmallVector<uint64_t, 64> Record;
2332 
2333   if (F.hasMetadata()) {
2334     pushGlobalMetadataAttachment(Record, F);
2335     Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2336     Record.clear();
2337   }
2338 
2339   // Write metadata attachments
2340   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
2341   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2342   for (const BasicBlock &BB : F)
2343     for (const Instruction &I : BB) {
2344       MDs.clear();
2345       I.getAllMetadataOtherThanDebugLoc(MDs);
2346 
2347       // If no metadata, ignore instruction.
2348       if (MDs.empty()) continue;
2349 
2350       Record.push_back(VE.getInstructionID(&I));
2351 
2352       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
2353         Record.push_back(MDs[i].first);
2354         Record.push_back(VE.getMetadataID(MDs[i].second));
2355       }
2356       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2357       Record.clear();
2358     }
2359 
2360   Stream.ExitBlock();
2361 }
2362 
2363 void ModuleBitcodeWriter::writeModuleMetadataKinds() {
2364   SmallVector<uint64_t, 64> Record;
2365 
2366   // Write metadata kinds
2367   // METADATA_KIND - [n x [id, name]]
2368   SmallVector<StringRef, 8> Names;
2369   M.getMDKindNames(Names);
2370 
2371   if (Names.empty()) return;
2372 
2373   Stream.EnterSubblock(bitc::METADATA_KIND_BLOCK_ID, 3);
2374 
2375   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
2376     Record.push_back(MDKindID);
2377     StringRef KName = Names[MDKindID];
2378     Record.append(KName.begin(), KName.end());
2379 
2380     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
2381     Record.clear();
2382   }
2383 
2384   Stream.ExitBlock();
2385 }
2386 
2387 void ModuleBitcodeWriter::writeOperandBundleTags() {
2388   // Write metadata kinds
2389   //
2390   // OPERAND_BUNDLE_TAGS_BLOCK_ID : N x OPERAND_BUNDLE_TAG
2391   //
2392   // OPERAND_BUNDLE_TAG - [strchr x N]
2393 
2394   SmallVector<StringRef, 8> Tags;
2395   M.getOperandBundleTags(Tags);
2396 
2397   if (Tags.empty())
2398     return;
2399 
2400   Stream.EnterSubblock(bitc::OPERAND_BUNDLE_TAGS_BLOCK_ID, 3);
2401 
2402   SmallVector<uint64_t, 64> Record;
2403 
2404   for (auto Tag : Tags) {
2405     Record.append(Tag.begin(), Tag.end());
2406 
2407     Stream.EmitRecord(bitc::OPERAND_BUNDLE_TAG, Record, 0);
2408     Record.clear();
2409   }
2410 
2411   Stream.ExitBlock();
2412 }
2413 
2414 void ModuleBitcodeWriter::writeSyncScopeNames() {
2415   SmallVector<StringRef, 8> SSNs;
2416   M.getContext().getSyncScopeNames(SSNs);
2417   if (SSNs.empty())
2418     return;
2419 
2420   Stream.EnterSubblock(bitc::SYNC_SCOPE_NAMES_BLOCK_ID, 2);
2421 
2422   SmallVector<uint64_t, 64> Record;
2423   for (auto SSN : SSNs) {
2424     Record.append(SSN.begin(), SSN.end());
2425     Stream.EmitRecord(bitc::SYNC_SCOPE_NAME, Record, 0);
2426     Record.clear();
2427   }
2428 
2429   Stream.ExitBlock();
2430 }
2431 
2432 void ModuleBitcodeWriter::writeConstants(unsigned FirstVal, unsigned LastVal,
2433                                          bool isGlobal) {
2434   if (FirstVal == LastVal) return;
2435 
2436   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
2437 
2438   unsigned AggregateAbbrev = 0;
2439   unsigned String8Abbrev = 0;
2440   unsigned CString7Abbrev = 0;
2441   unsigned CString6Abbrev = 0;
2442   // If this is a constant pool for the module, emit module-specific abbrevs.
2443   if (isGlobal) {
2444     // Abbrev for CST_CODE_AGGREGATE.
2445     auto Abbv = std::make_shared<BitCodeAbbrev>();
2446     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
2447     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2448     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
2449     AggregateAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2450 
2451     // Abbrev for CST_CODE_STRING.
2452     Abbv = std::make_shared<BitCodeAbbrev>();
2453     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
2454     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2455     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2456     String8Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2457     // Abbrev for CST_CODE_CSTRING.
2458     Abbv = std::make_shared<BitCodeAbbrev>();
2459     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2460     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2461     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2462     CString7Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2463     // Abbrev for CST_CODE_CSTRING.
2464     Abbv = std::make_shared<BitCodeAbbrev>();
2465     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2466     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2467     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2468     CString6Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2469   }
2470 
2471   SmallVector<uint64_t, 64> Record;
2472 
2473   const ValueEnumerator::ValueList &Vals = VE.getValues();
2474   Type *LastTy = nullptr;
2475   for (unsigned i = FirstVal; i != LastVal; ++i) {
2476     const Value *V = Vals[i].first;
2477     // If we need to switch types, do so now.
2478     if (V->getType() != LastTy) {
2479       LastTy = V->getType();
2480       Record.push_back(VE.getTypeID(LastTy));
2481       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
2482                         CONSTANTS_SETTYPE_ABBREV);
2483       Record.clear();
2484     }
2485 
2486     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
2487       Record.push_back(VE.getTypeID(IA->getFunctionType()));
2488       Record.push_back(
2489           unsigned(IA->hasSideEffects()) | unsigned(IA->isAlignStack()) << 1 |
2490           unsigned(IA->getDialect() & 1) << 2 | unsigned(IA->canThrow()) << 3);
2491 
2492       // Add the asm string.
2493       const std::string &AsmStr = IA->getAsmString();
2494       Record.push_back(AsmStr.size());
2495       Record.append(AsmStr.begin(), AsmStr.end());
2496 
2497       // Add the constraint string.
2498       const std::string &ConstraintStr = IA->getConstraintString();
2499       Record.push_back(ConstraintStr.size());
2500       Record.append(ConstraintStr.begin(), ConstraintStr.end());
2501       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
2502       Record.clear();
2503       continue;
2504     }
2505     const Constant *C = cast<Constant>(V);
2506     unsigned Code = -1U;
2507     unsigned AbbrevToUse = 0;
2508     if (C->isNullValue()) {
2509       Code = bitc::CST_CODE_NULL;
2510     } else if (isa<PoisonValue>(C)) {
2511       Code = bitc::CST_CODE_POISON;
2512     } else if (isa<UndefValue>(C)) {
2513       Code = bitc::CST_CODE_UNDEF;
2514     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
2515       if (IV->getBitWidth() <= 64) {
2516         uint64_t V = IV->getSExtValue();
2517         emitSignedInt64(Record, V);
2518         Code = bitc::CST_CODE_INTEGER;
2519         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
2520       } else {                             // Wide integers, > 64 bits in size.
2521         emitWideAPInt(Record, IV->getValue());
2522         Code = bitc::CST_CODE_WIDE_INTEGER;
2523       }
2524     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
2525       Code = bitc::CST_CODE_FLOAT;
2526       Type *Ty = CFP->getType();
2527       if (Ty->isHalfTy() || Ty->isBFloatTy() || Ty->isFloatTy() ||
2528           Ty->isDoubleTy()) {
2529         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
2530       } else if (Ty->isX86_FP80Ty()) {
2531         // api needed to prevent premature destruction
2532         // bits are not in the same order as a normal i80 APInt, compensate.
2533         APInt api = CFP->getValueAPF().bitcastToAPInt();
2534         const uint64_t *p = api.getRawData();
2535         Record.push_back((p[1] << 48) | (p[0] >> 16));
2536         Record.push_back(p[0] & 0xffffLL);
2537       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
2538         APInt api = CFP->getValueAPF().bitcastToAPInt();
2539         const uint64_t *p = api.getRawData();
2540         Record.push_back(p[0]);
2541         Record.push_back(p[1]);
2542       } else {
2543         assert(0 && "Unknown FP type!");
2544       }
2545     } else if (isa<ConstantDataSequential>(C) &&
2546                cast<ConstantDataSequential>(C)->isString()) {
2547       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
2548       // Emit constant strings specially.
2549       unsigned NumElts = Str->getNumElements();
2550       // If this is a null-terminated string, use the denser CSTRING encoding.
2551       if (Str->isCString()) {
2552         Code = bitc::CST_CODE_CSTRING;
2553         --NumElts;  // Don't encode the null, which isn't allowed by char6.
2554       } else {
2555         Code = bitc::CST_CODE_STRING;
2556         AbbrevToUse = String8Abbrev;
2557       }
2558       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
2559       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
2560       for (unsigned i = 0; i != NumElts; ++i) {
2561         unsigned char V = Str->getElementAsInteger(i);
2562         Record.push_back(V);
2563         isCStr7 &= (V & 128) == 0;
2564         if (isCStrChar6)
2565           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
2566       }
2567 
2568       if (isCStrChar6)
2569         AbbrevToUse = CString6Abbrev;
2570       else if (isCStr7)
2571         AbbrevToUse = CString7Abbrev;
2572     } else if (const ConstantDataSequential *CDS =
2573                   dyn_cast<ConstantDataSequential>(C)) {
2574       Code = bitc::CST_CODE_DATA;
2575       Type *EltTy = CDS->getElementType();
2576       if (isa<IntegerType>(EltTy)) {
2577         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2578           Record.push_back(CDS->getElementAsInteger(i));
2579       } else {
2580         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2581           Record.push_back(
2582               CDS->getElementAsAPFloat(i).bitcastToAPInt().getLimitedValue());
2583       }
2584     } else if (isa<ConstantAggregate>(C)) {
2585       Code = bitc::CST_CODE_AGGREGATE;
2586       for (const Value *Op : C->operands())
2587         Record.push_back(VE.getValueID(Op));
2588       AbbrevToUse = AggregateAbbrev;
2589     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
2590       switch (CE->getOpcode()) {
2591       default:
2592         if (Instruction::isCast(CE->getOpcode())) {
2593           Code = bitc::CST_CODE_CE_CAST;
2594           Record.push_back(getEncodedCastOpcode(CE->getOpcode()));
2595           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2596           Record.push_back(VE.getValueID(C->getOperand(0)));
2597           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
2598         } else {
2599           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
2600           Code = bitc::CST_CODE_CE_BINOP;
2601           Record.push_back(getEncodedBinaryOpcode(CE->getOpcode()));
2602           Record.push_back(VE.getValueID(C->getOperand(0)));
2603           Record.push_back(VE.getValueID(C->getOperand(1)));
2604           uint64_t Flags = getOptimizationFlags(CE);
2605           if (Flags != 0)
2606             Record.push_back(Flags);
2607         }
2608         break;
2609       case Instruction::FNeg: {
2610         assert(CE->getNumOperands() == 1 && "Unknown constant expr!");
2611         Code = bitc::CST_CODE_CE_UNOP;
2612         Record.push_back(getEncodedUnaryOpcode(CE->getOpcode()));
2613         Record.push_back(VE.getValueID(C->getOperand(0)));
2614         uint64_t Flags = getOptimizationFlags(CE);
2615         if (Flags != 0)
2616           Record.push_back(Flags);
2617         break;
2618       }
2619       case Instruction::GetElementPtr: {
2620         Code = bitc::CST_CODE_CE_GEP;
2621         const auto *GO = cast<GEPOperator>(C);
2622         Record.push_back(VE.getTypeID(GO->getSourceElementType()));
2623         if (Optional<unsigned> Idx = GO->getInRangeIndex()) {
2624           Code = bitc::CST_CODE_CE_GEP_WITH_INRANGE_INDEX;
2625           Record.push_back((*Idx << 1) | GO->isInBounds());
2626         } else if (GO->isInBounds())
2627           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
2628         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
2629           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
2630           Record.push_back(VE.getValueID(C->getOperand(i)));
2631         }
2632         break;
2633       }
2634       case Instruction::Select:
2635         Code = bitc::CST_CODE_CE_SELECT;
2636         Record.push_back(VE.getValueID(C->getOperand(0)));
2637         Record.push_back(VE.getValueID(C->getOperand(1)));
2638         Record.push_back(VE.getValueID(C->getOperand(2)));
2639         break;
2640       case Instruction::ExtractElement:
2641         Code = bitc::CST_CODE_CE_EXTRACTELT;
2642         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2643         Record.push_back(VE.getValueID(C->getOperand(0)));
2644         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
2645         Record.push_back(VE.getValueID(C->getOperand(1)));
2646         break;
2647       case Instruction::InsertElement:
2648         Code = bitc::CST_CODE_CE_INSERTELT;
2649         Record.push_back(VE.getValueID(C->getOperand(0)));
2650         Record.push_back(VE.getValueID(C->getOperand(1)));
2651         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
2652         Record.push_back(VE.getValueID(C->getOperand(2)));
2653         break;
2654       case Instruction::ShuffleVector:
2655         // If the return type and argument types are the same, this is a
2656         // standard shufflevector instruction.  If the types are different,
2657         // then the shuffle is widening or truncating the input vectors, and
2658         // the argument type must also be encoded.
2659         if (C->getType() == C->getOperand(0)->getType()) {
2660           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
2661         } else {
2662           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
2663           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2664         }
2665         Record.push_back(VE.getValueID(C->getOperand(0)));
2666         Record.push_back(VE.getValueID(C->getOperand(1)));
2667         Record.push_back(VE.getValueID(CE->getShuffleMaskForBitcode()));
2668         break;
2669       case Instruction::ICmp:
2670       case Instruction::FCmp:
2671         Code = bitc::CST_CODE_CE_CMP;
2672         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2673         Record.push_back(VE.getValueID(C->getOperand(0)));
2674         Record.push_back(VE.getValueID(C->getOperand(1)));
2675         Record.push_back(CE->getPredicate());
2676         break;
2677       }
2678     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
2679       Code = bitc::CST_CODE_BLOCKADDRESS;
2680       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
2681       Record.push_back(VE.getValueID(BA->getFunction()));
2682       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
2683     } else if (const auto *Equiv = dyn_cast<DSOLocalEquivalent>(C)) {
2684       Code = bitc::CST_CODE_DSO_LOCAL_EQUIVALENT;
2685       Record.push_back(VE.getTypeID(Equiv->getGlobalValue()->getType()));
2686       Record.push_back(VE.getValueID(Equiv->getGlobalValue()));
2687     } else if (const auto *NC = dyn_cast<NoCFIValue>(C)) {
2688       Code = bitc::CST_CODE_NO_CFI_VALUE;
2689       Record.push_back(VE.getTypeID(NC->getGlobalValue()->getType()));
2690       Record.push_back(VE.getValueID(NC->getGlobalValue()));
2691     } else {
2692 #ifndef NDEBUG
2693       C->dump();
2694 #endif
2695       llvm_unreachable("Unknown constant!");
2696     }
2697     Stream.EmitRecord(Code, Record, AbbrevToUse);
2698     Record.clear();
2699   }
2700 
2701   Stream.ExitBlock();
2702 }
2703 
2704 void ModuleBitcodeWriter::writeModuleConstants() {
2705   const ValueEnumerator::ValueList &Vals = VE.getValues();
2706 
2707   // Find the first constant to emit, which is the first non-globalvalue value.
2708   // We know globalvalues have been emitted by WriteModuleInfo.
2709   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
2710     if (!isa<GlobalValue>(Vals[i].first)) {
2711       writeConstants(i, Vals.size(), true);
2712       return;
2713     }
2714   }
2715 }
2716 
2717 /// pushValueAndType - The file has to encode both the value and type id for
2718 /// many values, because we need to know what type to create for forward
2719 /// references.  However, most operands are not forward references, so this type
2720 /// field is not needed.
2721 ///
2722 /// This function adds V's value ID to Vals.  If the value ID is higher than the
2723 /// instruction ID, then it is a forward reference, and it also includes the
2724 /// type ID.  The value ID that is written is encoded relative to the InstID.
2725 bool ModuleBitcodeWriter::pushValueAndType(const Value *V, unsigned InstID,
2726                                            SmallVectorImpl<unsigned> &Vals) {
2727   unsigned ValID = VE.getValueID(V);
2728   // Make encoding relative to the InstID.
2729   Vals.push_back(InstID - ValID);
2730   if (ValID >= InstID) {
2731     Vals.push_back(VE.getTypeID(V->getType()));
2732     return true;
2733   }
2734   return false;
2735 }
2736 
2737 void ModuleBitcodeWriter::writeOperandBundles(const CallBase &CS,
2738                                               unsigned InstID) {
2739   SmallVector<unsigned, 64> Record;
2740   LLVMContext &C = CS.getContext();
2741 
2742   for (unsigned i = 0, e = CS.getNumOperandBundles(); i != e; ++i) {
2743     const auto &Bundle = CS.getOperandBundleAt(i);
2744     Record.push_back(C.getOperandBundleTagID(Bundle.getTagName()));
2745 
2746     for (auto &Input : Bundle.Inputs)
2747       pushValueAndType(Input, InstID, Record);
2748 
2749     Stream.EmitRecord(bitc::FUNC_CODE_OPERAND_BUNDLE, Record);
2750     Record.clear();
2751   }
2752 }
2753 
2754 /// pushValue - Like pushValueAndType, but where the type of the value is
2755 /// omitted (perhaps it was already encoded in an earlier operand).
2756 void ModuleBitcodeWriter::pushValue(const Value *V, unsigned InstID,
2757                                     SmallVectorImpl<unsigned> &Vals) {
2758   unsigned ValID = VE.getValueID(V);
2759   Vals.push_back(InstID - ValID);
2760 }
2761 
2762 void ModuleBitcodeWriter::pushValueSigned(const Value *V, unsigned InstID,
2763                                           SmallVectorImpl<uint64_t> &Vals) {
2764   unsigned ValID = VE.getValueID(V);
2765   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
2766   emitSignedInt64(Vals, diff);
2767 }
2768 
2769 /// WriteInstruction - Emit an instruction to the specified stream.
2770 void ModuleBitcodeWriter::writeInstruction(const Instruction &I,
2771                                            unsigned InstID,
2772                                            SmallVectorImpl<unsigned> &Vals) {
2773   unsigned Code = 0;
2774   unsigned AbbrevToUse = 0;
2775   VE.setInstructionID(&I);
2776   switch (I.getOpcode()) {
2777   default:
2778     if (Instruction::isCast(I.getOpcode())) {
2779       Code = bitc::FUNC_CODE_INST_CAST;
2780       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2781         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
2782       Vals.push_back(VE.getTypeID(I.getType()));
2783       Vals.push_back(getEncodedCastOpcode(I.getOpcode()));
2784     } else {
2785       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
2786       Code = bitc::FUNC_CODE_INST_BINOP;
2787       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2788         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
2789       pushValue(I.getOperand(1), InstID, Vals);
2790       Vals.push_back(getEncodedBinaryOpcode(I.getOpcode()));
2791       uint64_t Flags = getOptimizationFlags(&I);
2792       if (Flags != 0) {
2793         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
2794           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
2795         Vals.push_back(Flags);
2796       }
2797     }
2798     break;
2799   case Instruction::FNeg: {
2800     Code = bitc::FUNC_CODE_INST_UNOP;
2801     if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2802       AbbrevToUse = FUNCTION_INST_UNOP_ABBREV;
2803     Vals.push_back(getEncodedUnaryOpcode(I.getOpcode()));
2804     uint64_t Flags = getOptimizationFlags(&I);
2805     if (Flags != 0) {
2806       if (AbbrevToUse == FUNCTION_INST_UNOP_ABBREV)
2807         AbbrevToUse = FUNCTION_INST_UNOP_FLAGS_ABBREV;
2808       Vals.push_back(Flags);
2809     }
2810     break;
2811   }
2812   case Instruction::GetElementPtr: {
2813     Code = bitc::FUNC_CODE_INST_GEP;
2814     AbbrevToUse = FUNCTION_INST_GEP_ABBREV;
2815     auto &GEPInst = cast<GetElementPtrInst>(I);
2816     Vals.push_back(GEPInst.isInBounds());
2817     Vals.push_back(VE.getTypeID(GEPInst.getSourceElementType()));
2818     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
2819       pushValueAndType(I.getOperand(i), InstID, Vals);
2820     break;
2821   }
2822   case Instruction::ExtractValue: {
2823     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
2824     pushValueAndType(I.getOperand(0), InstID, Vals);
2825     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
2826     Vals.append(EVI->idx_begin(), EVI->idx_end());
2827     break;
2828   }
2829   case Instruction::InsertValue: {
2830     Code = bitc::FUNC_CODE_INST_INSERTVAL;
2831     pushValueAndType(I.getOperand(0), InstID, Vals);
2832     pushValueAndType(I.getOperand(1), InstID, Vals);
2833     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
2834     Vals.append(IVI->idx_begin(), IVI->idx_end());
2835     break;
2836   }
2837   case Instruction::Select: {
2838     Code = bitc::FUNC_CODE_INST_VSELECT;
2839     pushValueAndType(I.getOperand(1), InstID, Vals);
2840     pushValue(I.getOperand(2), InstID, Vals);
2841     pushValueAndType(I.getOperand(0), InstID, Vals);
2842     uint64_t Flags = getOptimizationFlags(&I);
2843     if (Flags != 0)
2844       Vals.push_back(Flags);
2845     break;
2846   }
2847   case Instruction::ExtractElement:
2848     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
2849     pushValueAndType(I.getOperand(0), InstID, Vals);
2850     pushValueAndType(I.getOperand(1), InstID, Vals);
2851     break;
2852   case Instruction::InsertElement:
2853     Code = bitc::FUNC_CODE_INST_INSERTELT;
2854     pushValueAndType(I.getOperand(0), InstID, Vals);
2855     pushValue(I.getOperand(1), InstID, Vals);
2856     pushValueAndType(I.getOperand(2), InstID, Vals);
2857     break;
2858   case Instruction::ShuffleVector:
2859     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
2860     pushValueAndType(I.getOperand(0), InstID, Vals);
2861     pushValue(I.getOperand(1), InstID, Vals);
2862     pushValue(cast<ShuffleVectorInst>(I).getShuffleMaskForBitcode(), InstID,
2863               Vals);
2864     break;
2865   case Instruction::ICmp:
2866   case Instruction::FCmp: {
2867     // compare returning Int1Ty or vector of Int1Ty
2868     Code = bitc::FUNC_CODE_INST_CMP2;
2869     pushValueAndType(I.getOperand(0), InstID, Vals);
2870     pushValue(I.getOperand(1), InstID, Vals);
2871     Vals.push_back(cast<CmpInst>(I).getPredicate());
2872     uint64_t Flags = getOptimizationFlags(&I);
2873     if (Flags != 0)
2874       Vals.push_back(Flags);
2875     break;
2876   }
2877 
2878   case Instruction::Ret:
2879     {
2880       Code = bitc::FUNC_CODE_INST_RET;
2881       unsigned NumOperands = I.getNumOperands();
2882       if (NumOperands == 0)
2883         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
2884       else if (NumOperands == 1) {
2885         if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2886           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
2887       } else {
2888         for (unsigned i = 0, e = NumOperands; i != e; ++i)
2889           pushValueAndType(I.getOperand(i), InstID, Vals);
2890       }
2891     }
2892     break;
2893   case Instruction::Br:
2894     {
2895       Code = bitc::FUNC_CODE_INST_BR;
2896       const BranchInst &II = cast<BranchInst>(I);
2897       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
2898       if (II.isConditional()) {
2899         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
2900         pushValue(II.getCondition(), InstID, Vals);
2901       }
2902     }
2903     break;
2904   case Instruction::Switch:
2905     {
2906       Code = bitc::FUNC_CODE_INST_SWITCH;
2907       const SwitchInst &SI = cast<SwitchInst>(I);
2908       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
2909       pushValue(SI.getCondition(), InstID, Vals);
2910       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
2911       for (auto Case : SI.cases()) {
2912         Vals.push_back(VE.getValueID(Case.getCaseValue()));
2913         Vals.push_back(VE.getValueID(Case.getCaseSuccessor()));
2914       }
2915     }
2916     break;
2917   case Instruction::IndirectBr:
2918     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
2919     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2920     // Encode the address operand as relative, but not the basic blocks.
2921     pushValue(I.getOperand(0), InstID, Vals);
2922     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
2923       Vals.push_back(VE.getValueID(I.getOperand(i)));
2924     break;
2925 
2926   case Instruction::Invoke: {
2927     const InvokeInst *II = cast<InvokeInst>(&I);
2928     const Value *Callee = II->getCalledOperand();
2929     FunctionType *FTy = II->getFunctionType();
2930 
2931     if (II->hasOperandBundles())
2932       writeOperandBundles(*II, InstID);
2933 
2934     Code = bitc::FUNC_CODE_INST_INVOKE;
2935 
2936     Vals.push_back(VE.getAttributeListID(II->getAttributes()));
2937     Vals.push_back(II->getCallingConv() | 1 << 13);
2938     Vals.push_back(VE.getValueID(II->getNormalDest()));
2939     Vals.push_back(VE.getValueID(II->getUnwindDest()));
2940     Vals.push_back(VE.getTypeID(FTy));
2941     pushValueAndType(Callee, InstID, Vals);
2942 
2943     // Emit value #'s for the fixed parameters.
2944     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
2945       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
2946 
2947     // Emit type/value pairs for varargs params.
2948     if (FTy->isVarArg()) {
2949       for (unsigned i = FTy->getNumParams(), e = II->arg_size(); i != e; ++i)
2950         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
2951     }
2952     break;
2953   }
2954   case Instruction::Resume:
2955     Code = bitc::FUNC_CODE_INST_RESUME;
2956     pushValueAndType(I.getOperand(0), InstID, Vals);
2957     break;
2958   case Instruction::CleanupRet: {
2959     Code = bitc::FUNC_CODE_INST_CLEANUPRET;
2960     const auto &CRI = cast<CleanupReturnInst>(I);
2961     pushValue(CRI.getCleanupPad(), InstID, Vals);
2962     if (CRI.hasUnwindDest())
2963       Vals.push_back(VE.getValueID(CRI.getUnwindDest()));
2964     break;
2965   }
2966   case Instruction::CatchRet: {
2967     Code = bitc::FUNC_CODE_INST_CATCHRET;
2968     const auto &CRI = cast<CatchReturnInst>(I);
2969     pushValue(CRI.getCatchPad(), InstID, Vals);
2970     Vals.push_back(VE.getValueID(CRI.getSuccessor()));
2971     break;
2972   }
2973   case Instruction::CleanupPad:
2974   case Instruction::CatchPad: {
2975     const auto &FuncletPad = cast<FuncletPadInst>(I);
2976     Code = isa<CatchPadInst>(FuncletPad) ? bitc::FUNC_CODE_INST_CATCHPAD
2977                                          : bitc::FUNC_CODE_INST_CLEANUPPAD;
2978     pushValue(FuncletPad.getParentPad(), InstID, Vals);
2979 
2980     unsigned NumArgOperands = FuncletPad.getNumArgOperands();
2981     Vals.push_back(NumArgOperands);
2982     for (unsigned Op = 0; Op != NumArgOperands; ++Op)
2983       pushValueAndType(FuncletPad.getArgOperand(Op), InstID, Vals);
2984     break;
2985   }
2986   case Instruction::CatchSwitch: {
2987     Code = bitc::FUNC_CODE_INST_CATCHSWITCH;
2988     const auto &CatchSwitch = cast<CatchSwitchInst>(I);
2989 
2990     pushValue(CatchSwitch.getParentPad(), InstID, Vals);
2991 
2992     unsigned NumHandlers = CatchSwitch.getNumHandlers();
2993     Vals.push_back(NumHandlers);
2994     for (const BasicBlock *CatchPadBB : CatchSwitch.handlers())
2995       Vals.push_back(VE.getValueID(CatchPadBB));
2996 
2997     if (CatchSwitch.hasUnwindDest())
2998       Vals.push_back(VE.getValueID(CatchSwitch.getUnwindDest()));
2999     break;
3000   }
3001   case Instruction::CallBr: {
3002     const CallBrInst *CBI = cast<CallBrInst>(&I);
3003     const Value *Callee = CBI->getCalledOperand();
3004     FunctionType *FTy = CBI->getFunctionType();
3005 
3006     if (CBI->hasOperandBundles())
3007       writeOperandBundles(*CBI, InstID);
3008 
3009     Code = bitc::FUNC_CODE_INST_CALLBR;
3010 
3011     Vals.push_back(VE.getAttributeListID(CBI->getAttributes()));
3012 
3013     Vals.push_back(CBI->getCallingConv() << bitc::CALL_CCONV |
3014                    1 << bitc::CALL_EXPLICIT_TYPE);
3015 
3016     Vals.push_back(VE.getValueID(CBI->getDefaultDest()));
3017     Vals.push_back(CBI->getNumIndirectDests());
3018     for (unsigned i = 0, e = CBI->getNumIndirectDests(); i != e; ++i)
3019       Vals.push_back(VE.getValueID(CBI->getIndirectDest(i)));
3020 
3021     Vals.push_back(VE.getTypeID(FTy));
3022     pushValueAndType(Callee, InstID, Vals);
3023 
3024     // Emit value #'s for the fixed parameters.
3025     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
3026       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
3027 
3028     // Emit type/value pairs for varargs params.
3029     if (FTy->isVarArg()) {
3030       for (unsigned i = FTy->getNumParams(), e = CBI->arg_size(); i != e; ++i)
3031         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
3032     }
3033     break;
3034   }
3035   case Instruction::Unreachable:
3036     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
3037     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
3038     break;
3039 
3040   case Instruction::PHI: {
3041     const PHINode &PN = cast<PHINode>(I);
3042     Code = bitc::FUNC_CODE_INST_PHI;
3043     // With the newer instruction encoding, forward references could give
3044     // negative valued IDs.  This is most common for PHIs, so we use
3045     // signed VBRs.
3046     SmallVector<uint64_t, 128> Vals64;
3047     Vals64.push_back(VE.getTypeID(PN.getType()));
3048     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
3049       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64);
3050       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
3051     }
3052 
3053     uint64_t Flags = getOptimizationFlags(&I);
3054     if (Flags != 0)
3055       Vals64.push_back(Flags);
3056 
3057     // Emit a Vals64 vector and exit.
3058     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
3059     Vals64.clear();
3060     return;
3061   }
3062 
3063   case Instruction::LandingPad: {
3064     const LandingPadInst &LP = cast<LandingPadInst>(I);
3065     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
3066     Vals.push_back(VE.getTypeID(LP.getType()));
3067     Vals.push_back(LP.isCleanup());
3068     Vals.push_back(LP.getNumClauses());
3069     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
3070       if (LP.isCatch(I))
3071         Vals.push_back(LandingPadInst::Catch);
3072       else
3073         Vals.push_back(LandingPadInst::Filter);
3074       pushValueAndType(LP.getClause(I), InstID, Vals);
3075     }
3076     break;
3077   }
3078 
3079   case Instruction::Alloca: {
3080     Code = bitc::FUNC_CODE_INST_ALLOCA;
3081     const AllocaInst &AI = cast<AllocaInst>(I);
3082     Vals.push_back(VE.getTypeID(AI.getAllocatedType()));
3083     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
3084     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
3085     using APV = AllocaPackedValues;
3086     unsigned Record = 0;
3087     unsigned EncodedAlign = getEncodedAlign(AI.getAlign());
3088     Bitfield::set<APV::AlignLower>(
3089         Record, EncodedAlign & ((1 << APV::AlignLower::Bits) - 1));
3090     Bitfield::set<APV::AlignUpper>(Record,
3091                                    EncodedAlign >> APV::AlignLower::Bits);
3092     Bitfield::set<APV::UsedWithInAlloca>(Record, AI.isUsedWithInAlloca());
3093     Bitfield::set<APV::ExplicitType>(Record, true);
3094     Bitfield::set<APV::SwiftError>(Record, AI.isSwiftError());
3095     Vals.push_back(Record);
3096 
3097     unsigned AS = AI.getAddressSpace();
3098     if (AS != M.getDataLayout().getAllocaAddrSpace())
3099       Vals.push_back(AS);
3100     break;
3101   }
3102 
3103   case Instruction::Load:
3104     if (cast<LoadInst>(I).isAtomic()) {
3105       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
3106       pushValueAndType(I.getOperand(0), InstID, Vals);
3107     } else {
3108       Code = bitc::FUNC_CODE_INST_LOAD;
3109       if (!pushValueAndType(I.getOperand(0), InstID, Vals)) // ptr
3110         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
3111     }
3112     Vals.push_back(VE.getTypeID(I.getType()));
3113     Vals.push_back(getEncodedAlign(cast<LoadInst>(I).getAlign()));
3114     Vals.push_back(cast<LoadInst>(I).isVolatile());
3115     if (cast<LoadInst>(I).isAtomic()) {
3116       Vals.push_back(getEncodedOrdering(cast<LoadInst>(I).getOrdering()));
3117       Vals.push_back(getEncodedSyncScopeID(cast<LoadInst>(I).getSyncScopeID()));
3118     }
3119     break;
3120   case Instruction::Store:
3121     if (cast<StoreInst>(I).isAtomic())
3122       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
3123     else
3124       Code = bitc::FUNC_CODE_INST_STORE;
3125     pushValueAndType(I.getOperand(1), InstID, Vals); // ptrty + ptr
3126     pushValueAndType(I.getOperand(0), InstID, Vals); // valty + val
3127     Vals.push_back(getEncodedAlign(cast<StoreInst>(I).getAlign()));
3128     Vals.push_back(cast<StoreInst>(I).isVolatile());
3129     if (cast<StoreInst>(I).isAtomic()) {
3130       Vals.push_back(getEncodedOrdering(cast<StoreInst>(I).getOrdering()));
3131       Vals.push_back(
3132           getEncodedSyncScopeID(cast<StoreInst>(I).getSyncScopeID()));
3133     }
3134     break;
3135   case Instruction::AtomicCmpXchg:
3136     Code = bitc::FUNC_CODE_INST_CMPXCHG;
3137     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
3138     pushValueAndType(I.getOperand(1), InstID, Vals); // cmp.
3139     pushValue(I.getOperand(2), InstID, Vals);        // newval.
3140     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
3141     Vals.push_back(
3142         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
3143     Vals.push_back(
3144         getEncodedSyncScopeID(cast<AtomicCmpXchgInst>(I).getSyncScopeID()));
3145     Vals.push_back(
3146         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
3147     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
3148     Vals.push_back(getEncodedAlign(cast<AtomicCmpXchgInst>(I).getAlign()));
3149     break;
3150   case Instruction::AtomicRMW:
3151     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
3152     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
3153     pushValueAndType(I.getOperand(1), InstID, Vals); // valty + val
3154     Vals.push_back(
3155         getEncodedRMWOperation(cast<AtomicRMWInst>(I).getOperation()));
3156     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
3157     Vals.push_back(getEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
3158     Vals.push_back(
3159         getEncodedSyncScopeID(cast<AtomicRMWInst>(I).getSyncScopeID()));
3160     Vals.push_back(getEncodedAlign(cast<AtomicRMWInst>(I).getAlign()));
3161     break;
3162   case Instruction::Fence:
3163     Code = bitc::FUNC_CODE_INST_FENCE;
3164     Vals.push_back(getEncodedOrdering(cast<FenceInst>(I).getOrdering()));
3165     Vals.push_back(getEncodedSyncScopeID(cast<FenceInst>(I).getSyncScopeID()));
3166     break;
3167   case Instruction::Call: {
3168     const CallInst &CI = cast<CallInst>(I);
3169     FunctionType *FTy = CI.getFunctionType();
3170 
3171     if (CI.hasOperandBundles())
3172       writeOperandBundles(CI, InstID);
3173 
3174     Code = bitc::FUNC_CODE_INST_CALL;
3175 
3176     Vals.push_back(VE.getAttributeListID(CI.getAttributes()));
3177 
3178     unsigned Flags = getOptimizationFlags(&I);
3179     Vals.push_back(CI.getCallingConv() << bitc::CALL_CCONV |
3180                    unsigned(CI.isTailCall()) << bitc::CALL_TAIL |
3181                    unsigned(CI.isMustTailCall()) << bitc::CALL_MUSTTAIL |
3182                    1 << bitc::CALL_EXPLICIT_TYPE |
3183                    unsigned(CI.isNoTailCall()) << bitc::CALL_NOTAIL |
3184                    unsigned(Flags != 0) << bitc::CALL_FMF);
3185     if (Flags != 0)
3186       Vals.push_back(Flags);
3187 
3188     Vals.push_back(VE.getTypeID(FTy));
3189     pushValueAndType(CI.getCalledOperand(), InstID, Vals); // Callee
3190 
3191     // Emit value #'s for the fixed parameters.
3192     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
3193       // Check for labels (can happen with asm labels).
3194       if (FTy->getParamType(i)->isLabelTy())
3195         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
3196       else
3197         pushValue(CI.getArgOperand(i), InstID, Vals); // fixed param.
3198     }
3199 
3200     // Emit type/value pairs for varargs params.
3201     if (FTy->isVarArg()) {
3202       for (unsigned i = FTy->getNumParams(), e = CI.arg_size(); i != e; ++i)
3203         pushValueAndType(CI.getArgOperand(i), InstID, Vals); // varargs
3204     }
3205     break;
3206   }
3207   case Instruction::VAArg:
3208     Code = bitc::FUNC_CODE_INST_VAARG;
3209     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
3210     pushValue(I.getOperand(0), InstID, Vals);                   // valist.
3211     Vals.push_back(VE.getTypeID(I.getType())); // restype.
3212     break;
3213   case Instruction::Freeze:
3214     Code = bitc::FUNC_CODE_INST_FREEZE;
3215     pushValueAndType(I.getOperand(0), InstID, Vals);
3216     break;
3217   }
3218 
3219   Stream.EmitRecord(Code, Vals, AbbrevToUse);
3220   Vals.clear();
3221 }
3222 
3223 /// Write a GlobalValue VST to the module. The purpose of this data structure is
3224 /// to allow clients to efficiently find the function body.
3225 void ModuleBitcodeWriter::writeGlobalValueSymbolTable(
3226   DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3227   // Get the offset of the VST we are writing, and backpatch it into
3228   // the VST forward declaration record.
3229   uint64_t VSTOffset = Stream.GetCurrentBitNo();
3230   // The BitcodeStartBit was the stream offset of the identification block.
3231   VSTOffset -= bitcodeStartBit();
3232   assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
3233   // Note that we add 1 here because the offset is relative to one word
3234   // before the start of the identification block, which was historically
3235   // always the start of the regular bitcode header.
3236   Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32 + 1);
3237 
3238   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3239 
3240   auto Abbv = std::make_shared<BitCodeAbbrev>();
3241   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
3242   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
3243   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
3244   unsigned FnEntryAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3245 
3246   for (const Function &F : M) {
3247     uint64_t Record[2];
3248 
3249     if (F.isDeclaration())
3250       continue;
3251 
3252     Record[0] = VE.getValueID(&F);
3253 
3254     // Save the word offset of the function (from the start of the
3255     // actual bitcode written to the stream).
3256     uint64_t BitcodeIndex = FunctionToBitcodeIndex[&F] - bitcodeStartBit();
3257     assert((BitcodeIndex & 31) == 0 && "function block not 32-bit aligned");
3258     // Note that we add 1 here because the offset is relative to one word
3259     // before the start of the identification block, which was historically
3260     // always the start of the regular bitcode header.
3261     Record[1] = BitcodeIndex / 32 + 1;
3262 
3263     Stream.EmitRecord(bitc::VST_CODE_FNENTRY, Record, FnEntryAbbrev);
3264   }
3265 
3266   Stream.ExitBlock();
3267 }
3268 
3269 /// Emit names for arguments, instructions and basic blocks in a function.
3270 void ModuleBitcodeWriter::writeFunctionLevelValueSymbolTable(
3271     const ValueSymbolTable &VST) {
3272   if (VST.empty())
3273     return;
3274 
3275   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3276 
3277   // FIXME: Set up the abbrev, we know how many values there are!
3278   // FIXME: We know if the type names can use 7-bit ascii.
3279   SmallVector<uint64_t, 64> NameVals;
3280 
3281   for (const ValueName &Name : VST) {
3282     // Figure out the encoding to use for the name.
3283     StringEncoding Bits = getStringEncoding(Name.getKey());
3284 
3285     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
3286     NameVals.push_back(VE.getValueID(Name.getValue()));
3287 
3288     // VST_CODE_ENTRY:   [valueid, namechar x N]
3289     // VST_CODE_BBENTRY: [bbid, namechar x N]
3290     unsigned Code;
3291     if (isa<BasicBlock>(Name.getValue())) {
3292       Code = bitc::VST_CODE_BBENTRY;
3293       if (Bits == SE_Char6)
3294         AbbrevToUse = VST_BBENTRY_6_ABBREV;
3295     } else {
3296       Code = bitc::VST_CODE_ENTRY;
3297       if (Bits == SE_Char6)
3298         AbbrevToUse = VST_ENTRY_6_ABBREV;
3299       else if (Bits == SE_Fixed7)
3300         AbbrevToUse = VST_ENTRY_7_ABBREV;
3301     }
3302 
3303     for (const auto P : Name.getKey())
3304       NameVals.push_back((unsigned char)P);
3305 
3306     // Emit the finished record.
3307     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
3308     NameVals.clear();
3309   }
3310 
3311   Stream.ExitBlock();
3312 }
3313 
3314 void ModuleBitcodeWriter::writeUseList(UseListOrder &&Order) {
3315   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
3316   unsigned Code;
3317   if (isa<BasicBlock>(Order.V))
3318     Code = bitc::USELIST_CODE_BB;
3319   else
3320     Code = bitc::USELIST_CODE_DEFAULT;
3321 
3322   SmallVector<uint64_t, 64> Record(Order.Shuffle.begin(), Order.Shuffle.end());
3323   Record.push_back(VE.getValueID(Order.V));
3324   Stream.EmitRecord(Code, Record);
3325 }
3326 
3327 void ModuleBitcodeWriter::writeUseListBlock(const Function *F) {
3328   assert(VE.shouldPreserveUseListOrder() &&
3329          "Expected to be preserving use-list order");
3330 
3331   auto hasMore = [&]() {
3332     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
3333   };
3334   if (!hasMore())
3335     // Nothing to do.
3336     return;
3337 
3338   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
3339   while (hasMore()) {
3340     writeUseList(std::move(VE.UseListOrders.back()));
3341     VE.UseListOrders.pop_back();
3342   }
3343   Stream.ExitBlock();
3344 }
3345 
3346 /// Emit a function body to the module stream.
3347 void ModuleBitcodeWriter::writeFunction(
3348     const Function &F,
3349     DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3350   // Save the bitcode index of the start of this function block for recording
3351   // in the VST.
3352   FunctionToBitcodeIndex[&F] = Stream.GetCurrentBitNo();
3353 
3354   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
3355   VE.incorporateFunction(F);
3356 
3357   SmallVector<unsigned, 64> Vals;
3358 
3359   // Emit the number of basic blocks, so the reader can create them ahead of
3360   // time.
3361   Vals.push_back(VE.getBasicBlocks().size());
3362   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
3363   Vals.clear();
3364 
3365   // If there are function-local constants, emit them now.
3366   unsigned CstStart, CstEnd;
3367   VE.getFunctionConstantRange(CstStart, CstEnd);
3368   writeConstants(CstStart, CstEnd, false);
3369 
3370   // If there is function-local metadata, emit it now.
3371   writeFunctionMetadata(F);
3372 
3373   // Keep a running idea of what the instruction ID is.
3374   unsigned InstID = CstEnd;
3375 
3376   bool NeedsMetadataAttachment = F.hasMetadata();
3377 
3378   DILocation *LastDL = nullptr;
3379   SmallSetVector<Function *, 4> BlockAddressUsers;
3380 
3381   // Finally, emit all the instructions, in order.
3382   for (const BasicBlock &BB : F) {
3383     for (const Instruction &I : BB) {
3384       writeInstruction(I, InstID, Vals);
3385 
3386       if (!I.getType()->isVoidTy())
3387         ++InstID;
3388 
3389       // If the instruction has metadata, write a metadata attachment later.
3390       NeedsMetadataAttachment |= I.hasMetadataOtherThanDebugLoc();
3391 
3392       // If the instruction has a debug location, emit it.
3393       DILocation *DL = I.getDebugLoc();
3394       if (!DL)
3395         continue;
3396 
3397       if (DL == LastDL) {
3398         // Just repeat the same debug loc as last time.
3399         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
3400         continue;
3401       }
3402 
3403       Vals.push_back(DL->getLine());
3404       Vals.push_back(DL->getColumn());
3405       Vals.push_back(VE.getMetadataOrNullID(DL->getScope()));
3406       Vals.push_back(VE.getMetadataOrNullID(DL->getInlinedAt()));
3407       Vals.push_back(DL->isImplicitCode());
3408       Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
3409       Vals.clear();
3410 
3411       LastDL = DL;
3412     }
3413 
3414     if (BlockAddress *BA = BlockAddress::lookup(&BB)) {
3415       SmallVector<Value *> Worklist{BA};
3416       SmallPtrSet<Value *, 8> Visited{BA};
3417       while (!Worklist.empty()) {
3418         Value *V = Worklist.pop_back_val();
3419         for (User *U : V->users()) {
3420           if (auto *I = dyn_cast<Instruction>(U)) {
3421             Function *P = I->getFunction();
3422             if (P != &F)
3423               BlockAddressUsers.insert(P);
3424           } else if (isa<Constant>(U) && !isa<GlobalValue>(U) &&
3425                      Visited.insert(U).second)
3426             Worklist.push_back(U);
3427         }
3428       }
3429     }
3430   }
3431 
3432   if (!BlockAddressUsers.empty()) {
3433     Vals.resize(BlockAddressUsers.size());
3434     for (auto I : llvm::enumerate(BlockAddressUsers))
3435       Vals[I.index()] = VE.getValueID(I.value());
3436     Stream.EmitRecord(bitc::FUNC_CODE_BLOCKADDR_USERS, Vals);
3437     Vals.clear();
3438   }
3439 
3440   // Emit names for all the instructions etc.
3441   if (auto *Symtab = F.getValueSymbolTable())
3442     writeFunctionLevelValueSymbolTable(*Symtab);
3443 
3444   if (NeedsMetadataAttachment)
3445     writeFunctionMetadataAttachment(F);
3446   if (VE.shouldPreserveUseListOrder())
3447     writeUseListBlock(&F);
3448   VE.purgeFunction();
3449   Stream.ExitBlock();
3450 }
3451 
3452 // Emit blockinfo, which defines the standard abbreviations etc.
3453 void ModuleBitcodeWriter::writeBlockInfo() {
3454   // We only want to emit block info records for blocks that have multiple
3455   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
3456   // Other blocks can define their abbrevs inline.
3457   Stream.EnterBlockInfoBlock();
3458 
3459   { // 8-bit fixed-width VST_CODE_ENTRY/VST_CODE_BBENTRY strings.
3460     auto Abbv = std::make_shared<BitCodeAbbrev>();
3461     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
3462     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3463     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3464     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3465     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3466         VST_ENTRY_8_ABBREV)
3467       llvm_unreachable("Unexpected abbrev ordering!");
3468   }
3469 
3470   { // 7-bit fixed width VST_CODE_ENTRY strings.
3471     auto Abbv = std::make_shared<BitCodeAbbrev>();
3472     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3473     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3474     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3475     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3476     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3477         VST_ENTRY_7_ABBREV)
3478       llvm_unreachable("Unexpected abbrev ordering!");
3479   }
3480   { // 6-bit char6 VST_CODE_ENTRY strings.
3481     auto Abbv = std::make_shared<BitCodeAbbrev>();
3482     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3483     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3484     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3485     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3486     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3487         VST_ENTRY_6_ABBREV)
3488       llvm_unreachable("Unexpected abbrev ordering!");
3489   }
3490   { // 6-bit char6 VST_CODE_BBENTRY strings.
3491     auto Abbv = std::make_shared<BitCodeAbbrev>();
3492     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
3493     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3494     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3495     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3496     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3497         VST_BBENTRY_6_ABBREV)
3498       llvm_unreachable("Unexpected abbrev ordering!");
3499   }
3500 
3501   { // SETTYPE abbrev for CONSTANTS_BLOCK.
3502     auto Abbv = std::make_shared<BitCodeAbbrev>();
3503     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
3504     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
3505                               VE.computeBitsRequiredForTypeIndicies()));
3506     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3507         CONSTANTS_SETTYPE_ABBREV)
3508       llvm_unreachable("Unexpected abbrev ordering!");
3509   }
3510 
3511   { // INTEGER abbrev for CONSTANTS_BLOCK.
3512     auto Abbv = std::make_shared<BitCodeAbbrev>();
3513     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
3514     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3515     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3516         CONSTANTS_INTEGER_ABBREV)
3517       llvm_unreachable("Unexpected abbrev ordering!");
3518   }
3519 
3520   { // CE_CAST abbrev for CONSTANTS_BLOCK.
3521     auto Abbv = std::make_shared<BitCodeAbbrev>();
3522     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
3523     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
3524     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
3525                               VE.computeBitsRequiredForTypeIndicies()));
3526     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
3527 
3528     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3529         CONSTANTS_CE_CAST_Abbrev)
3530       llvm_unreachable("Unexpected abbrev ordering!");
3531   }
3532   { // NULL abbrev for CONSTANTS_BLOCK.
3533     auto Abbv = std::make_shared<BitCodeAbbrev>();
3534     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
3535     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3536         CONSTANTS_NULL_Abbrev)
3537       llvm_unreachable("Unexpected abbrev ordering!");
3538   }
3539 
3540   // FIXME: This should only use space for first class types!
3541 
3542   { // INST_LOAD abbrev for FUNCTION_BLOCK.
3543     auto Abbv = std::make_shared<BitCodeAbbrev>();
3544     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
3545     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
3546     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
3547                               VE.computeBitsRequiredForTypeIndicies()));
3548     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
3549     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
3550     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3551         FUNCTION_INST_LOAD_ABBREV)
3552       llvm_unreachable("Unexpected abbrev ordering!");
3553   }
3554   { // INST_UNOP abbrev for FUNCTION_BLOCK.
3555     auto Abbv = std::make_shared<BitCodeAbbrev>();
3556     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3557     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3558     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3559     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3560         FUNCTION_INST_UNOP_ABBREV)
3561       llvm_unreachable("Unexpected abbrev ordering!");
3562   }
3563   { // INST_UNOP_FLAGS abbrev for FUNCTION_BLOCK.
3564     auto Abbv = std::make_shared<BitCodeAbbrev>();
3565     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3566     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3567     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3568     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3569     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3570         FUNCTION_INST_UNOP_FLAGS_ABBREV)
3571       llvm_unreachable("Unexpected abbrev ordering!");
3572   }
3573   { // INST_BINOP abbrev for FUNCTION_BLOCK.
3574     auto Abbv = std::make_shared<BitCodeAbbrev>();
3575     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3576     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3577     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3578     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3579     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3580         FUNCTION_INST_BINOP_ABBREV)
3581       llvm_unreachable("Unexpected abbrev ordering!");
3582   }
3583   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
3584     auto Abbv = std::make_shared<BitCodeAbbrev>();
3585     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3586     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3587     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3588     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3589     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3590     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3591         FUNCTION_INST_BINOP_FLAGS_ABBREV)
3592       llvm_unreachable("Unexpected abbrev ordering!");
3593   }
3594   { // INST_CAST abbrev for FUNCTION_BLOCK.
3595     auto Abbv = std::make_shared<BitCodeAbbrev>();
3596     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
3597     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
3598     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
3599                               VE.computeBitsRequiredForTypeIndicies()));
3600     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
3601     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3602         FUNCTION_INST_CAST_ABBREV)
3603       llvm_unreachable("Unexpected abbrev ordering!");
3604   }
3605 
3606   { // INST_RET abbrev for FUNCTION_BLOCK.
3607     auto Abbv = std::make_shared<BitCodeAbbrev>();
3608     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3609     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3610         FUNCTION_INST_RET_VOID_ABBREV)
3611       llvm_unreachable("Unexpected abbrev ordering!");
3612   }
3613   { // INST_RET abbrev for FUNCTION_BLOCK.
3614     auto Abbv = std::make_shared<BitCodeAbbrev>();
3615     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3616     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
3617     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3618         FUNCTION_INST_RET_VAL_ABBREV)
3619       llvm_unreachable("Unexpected abbrev ordering!");
3620   }
3621   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
3622     auto Abbv = std::make_shared<BitCodeAbbrev>();
3623     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
3624     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3625         FUNCTION_INST_UNREACHABLE_ABBREV)
3626       llvm_unreachable("Unexpected abbrev ordering!");
3627   }
3628   {
3629     auto Abbv = std::make_shared<BitCodeAbbrev>();
3630     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_GEP));
3631     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
3632     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, // dest ty
3633                               Log2_32_Ceil(VE.getTypes().size() + 1)));
3634     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3635     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
3636     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3637         FUNCTION_INST_GEP_ABBREV)
3638       llvm_unreachable("Unexpected abbrev ordering!");
3639   }
3640 
3641   Stream.ExitBlock();
3642 }
3643 
3644 /// Write the module path strings, currently only used when generating
3645 /// a combined index file.
3646 void IndexBitcodeWriter::writeModStrings() {
3647   Stream.EnterSubblock(bitc::MODULE_STRTAB_BLOCK_ID, 3);
3648 
3649   // TODO: See which abbrev sizes we actually need to emit
3650 
3651   // 8-bit fixed-width MST_ENTRY strings.
3652   auto 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, 8));
3657   unsigned Abbrev8Bit = Stream.EmitAbbrev(std::move(Abbv));
3658 
3659   // 7-bit fixed width 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::Fixed, 7));
3665   unsigned Abbrev7Bit = Stream.EmitAbbrev(std::move(Abbv));
3666 
3667   // 6-bit char6 MST_ENTRY strings.
3668   Abbv = std::make_shared<BitCodeAbbrev>();
3669   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3670   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3671   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3672   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3673   unsigned Abbrev6Bit = Stream.EmitAbbrev(std::move(Abbv));
3674 
3675   // Module Hash, 160 bits SHA1. Optionally, emitted after each MST_CODE_ENTRY.
3676   Abbv = std::make_shared<BitCodeAbbrev>();
3677   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_HASH));
3678   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3679   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3680   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3681   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3682   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3683   unsigned AbbrevHash = Stream.EmitAbbrev(std::move(Abbv));
3684 
3685   SmallVector<unsigned, 64> Vals;
3686   forEachModule(
3687       [&](const StringMapEntry<std::pair<uint64_t, ModuleHash>> &MPSE) {
3688         StringRef Key = MPSE.getKey();
3689         const auto &Value = MPSE.getValue();
3690         StringEncoding Bits = getStringEncoding(Key);
3691         unsigned AbbrevToUse = Abbrev8Bit;
3692         if (Bits == SE_Char6)
3693           AbbrevToUse = Abbrev6Bit;
3694         else if (Bits == SE_Fixed7)
3695           AbbrevToUse = Abbrev7Bit;
3696 
3697         Vals.push_back(Value.first);
3698         Vals.append(Key.begin(), Key.end());
3699 
3700         // Emit the finished record.
3701         Stream.EmitRecord(bitc::MST_CODE_ENTRY, Vals, AbbrevToUse);
3702 
3703         // Emit an optional hash for the module now
3704         const auto &Hash = Value.second;
3705         if (llvm::any_of(Hash, [](uint32_t H) { return H; })) {
3706           Vals.assign(Hash.begin(), Hash.end());
3707           // Emit the hash record.
3708           Stream.EmitRecord(bitc::MST_CODE_HASH, Vals, AbbrevHash);
3709         }
3710 
3711         Vals.clear();
3712       });
3713   Stream.ExitBlock();
3714 }
3715 
3716 /// Write the function type metadata related records that need to appear before
3717 /// a function summary entry (whether per-module or combined).
3718 template <typename Fn>
3719 static void writeFunctionTypeMetadataRecords(BitstreamWriter &Stream,
3720                                              FunctionSummary *FS,
3721                                              Fn GetValueID) {
3722   if (!FS->type_tests().empty())
3723     Stream.EmitRecord(bitc::FS_TYPE_TESTS, FS->type_tests());
3724 
3725   SmallVector<uint64_t, 64> Record;
3726 
3727   auto WriteVFuncIdVec = [&](uint64_t Ty,
3728                              ArrayRef<FunctionSummary::VFuncId> VFs) {
3729     if (VFs.empty())
3730       return;
3731     Record.clear();
3732     for (auto &VF : VFs) {
3733       Record.push_back(VF.GUID);
3734       Record.push_back(VF.Offset);
3735     }
3736     Stream.EmitRecord(Ty, Record);
3737   };
3738 
3739   WriteVFuncIdVec(bitc::FS_TYPE_TEST_ASSUME_VCALLS,
3740                   FS->type_test_assume_vcalls());
3741   WriteVFuncIdVec(bitc::FS_TYPE_CHECKED_LOAD_VCALLS,
3742                   FS->type_checked_load_vcalls());
3743 
3744   auto WriteConstVCallVec = [&](uint64_t Ty,
3745                                 ArrayRef<FunctionSummary::ConstVCall> VCs) {
3746     for (auto &VC : VCs) {
3747       Record.clear();
3748       Record.push_back(VC.VFunc.GUID);
3749       Record.push_back(VC.VFunc.Offset);
3750       llvm::append_range(Record, VC.Args);
3751       Stream.EmitRecord(Ty, Record);
3752     }
3753   };
3754 
3755   WriteConstVCallVec(bitc::FS_TYPE_TEST_ASSUME_CONST_VCALL,
3756                      FS->type_test_assume_const_vcalls());
3757   WriteConstVCallVec(bitc::FS_TYPE_CHECKED_LOAD_CONST_VCALL,
3758                      FS->type_checked_load_const_vcalls());
3759 
3760   auto WriteRange = [&](ConstantRange Range) {
3761     Range = Range.sextOrTrunc(FunctionSummary::ParamAccess::RangeWidth);
3762     assert(Range.getLower().getNumWords() == 1);
3763     assert(Range.getUpper().getNumWords() == 1);
3764     emitSignedInt64(Record, *Range.getLower().getRawData());
3765     emitSignedInt64(Record, *Range.getUpper().getRawData());
3766   };
3767 
3768   if (!FS->paramAccesses().empty()) {
3769     Record.clear();
3770     for (auto &Arg : FS->paramAccesses()) {
3771       size_t UndoSize = Record.size();
3772       Record.push_back(Arg.ParamNo);
3773       WriteRange(Arg.Use);
3774       Record.push_back(Arg.Calls.size());
3775       for (auto &Call : Arg.Calls) {
3776         Record.push_back(Call.ParamNo);
3777         Optional<unsigned> ValueID = GetValueID(Call.Callee);
3778         if (!ValueID) {
3779           // If ValueID is unknown we can't drop just this call, we must drop
3780           // entire parameter.
3781           Record.resize(UndoSize);
3782           break;
3783         }
3784         Record.push_back(*ValueID);
3785         WriteRange(Call.Offsets);
3786       }
3787     }
3788     if (!Record.empty())
3789       Stream.EmitRecord(bitc::FS_PARAM_ACCESS, Record);
3790   }
3791 }
3792 
3793 /// Collect type IDs from type tests used by function.
3794 static void
3795 getReferencedTypeIds(FunctionSummary *FS,
3796                      std::set<GlobalValue::GUID> &ReferencedTypeIds) {
3797   if (!FS->type_tests().empty())
3798     for (auto &TT : FS->type_tests())
3799       ReferencedTypeIds.insert(TT);
3800 
3801   auto GetReferencedTypesFromVFuncIdVec =
3802       [&](ArrayRef<FunctionSummary::VFuncId> VFs) {
3803         for (auto &VF : VFs)
3804           ReferencedTypeIds.insert(VF.GUID);
3805       };
3806 
3807   GetReferencedTypesFromVFuncIdVec(FS->type_test_assume_vcalls());
3808   GetReferencedTypesFromVFuncIdVec(FS->type_checked_load_vcalls());
3809 
3810   auto GetReferencedTypesFromConstVCallVec =
3811       [&](ArrayRef<FunctionSummary::ConstVCall> VCs) {
3812         for (auto &VC : VCs)
3813           ReferencedTypeIds.insert(VC.VFunc.GUID);
3814       };
3815 
3816   GetReferencedTypesFromConstVCallVec(FS->type_test_assume_const_vcalls());
3817   GetReferencedTypesFromConstVCallVec(FS->type_checked_load_const_vcalls());
3818 }
3819 
3820 static void writeWholeProgramDevirtResolutionByArg(
3821     SmallVector<uint64_t, 64> &NameVals, const std::vector<uint64_t> &args,
3822     const WholeProgramDevirtResolution::ByArg &ByArg) {
3823   NameVals.push_back(args.size());
3824   llvm::append_range(NameVals, args);
3825 
3826   NameVals.push_back(ByArg.TheKind);
3827   NameVals.push_back(ByArg.Info);
3828   NameVals.push_back(ByArg.Byte);
3829   NameVals.push_back(ByArg.Bit);
3830 }
3831 
3832 static void writeWholeProgramDevirtResolution(
3833     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3834     uint64_t Id, const WholeProgramDevirtResolution &Wpd) {
3835   NameVals.push_back(Id);
3836 
3837   NameVals.push_back(Wpd.TheKind);
3838   NameVals.push_back(StrtabBuilder.add(Wpd.SingleImplName));
3839   NameVals.push_back(Wpd.SingleImplName.size());
3840 
3841   NameVals.push_back(Wpd.ResByArg.size());
3842   for (auto &A : Wpd.ResByArg)
3843     writeWholeProgramDevirtResolutionByArg(NameVals, A.first, A.second);
3844 }
3845 
3846 static void writeTypeIdSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
3847                                      StringTableBuilder &StrtabBuilder,
3848                                      const std::string &Id,
3849                                      const TypeIdSummary &Summary) {
3850   NameVals.push_back(StrtabBuilder.add(Id));
3851   NameVals.push_back(Id.size());
3852 
3853   NameVals.push_back(Summary.TTRes.TheKind);
3854   NameVals.push_back(Summary.TTRes.SizeM1BitWidth);
3855   NameVals.push_back(Summary.TTRes.AlignLog2);
3856   NameVals.push_back(Summary.TTRes.SizeM1);
3857   NameVals.push_back(Summary.TTRes.BitMask);
3858   NameVals.push_back(Summary.TTRes.InlineBits);
3859 
3860   for (auto &W : Summary.WPDRes)
3861     writeWholeProgramDevirtResolution(NameVals, StrtabBuilder, W.first,
3862                                       W.second);
3863 }
3864 
3865 static void writeTypeIdCompatibleVtableSummaryRecord(
3866     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3867     const std::string &Id, const TypeIdCompatibleVtableInfo &Summary,
3868     ValueEnumerator &VE) {
3869   NameVals.push_back(StrtabBuilder.add(Id));
3870   NameVals.push_back(Id.size());
3871 
3872   for (auto &P : Summary) {
3873     NameVals.push_back(P.AddressPointOffset);
3874     NameVals.push_back(VE.getValueID(P.VTableVI.getValue()));
3875   }
3876 }
3877 
3878 // Helper to emit a single function summary record.
3879 void ModuleBitcodeWriterBase::writePerModuleFunctionSummaryRecord(
3880     SmallVector<uint64_t, 64> &NameVals, GlobalValueSummary *Summary,
3881     unsigned ValueID, unsigned FSCallsAbbrev, unsigned FSCallsProfileAbbrev,
3882     const Function &F) {
3883   NameVals.push_back(ValueID);
3884 
3885   FunctionSummary *FS = cast<FunctionSummary>(Summary);
3886 
3887   writeFunctionTypeMetadataRecords(
3888       Stream, FS, [&](const ValueInfo &VI) -> Optional<unsigned> {
3889         return {VE.getValueID(VI.getValue())};
3890       });
3891 
3892   auto SpecialRefCnts = FS->specialRefCounts();
3893   NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
3894   NameVals.push_back(FS->instCount());
3895   NameVals.push_back(getEncodedFFlags(FS->fflags()));
3896   NameVals.push_back(FS->refs().size());
3897   NameVals.push_back(SpecialRefCnts.first);  // rorefcnt
3898   NameVals.push_back(SpecialRefCnts.second); // worefcnt
3899 
3900   for (auto &RI : FS->refs())
3901     NameVals.push_back(VE.getValueID(RI.getValue()));
3902 
3903   bool HasProfileData =
3904       F.hasProfileData() || ForceSummaryEdgesCold != FunctionSummary::FSHT_None;
3905   for (auto &ECI : FS->calls()) {
3906     NameVals.push_back(getValueId(ECI.first));
3907     if (HasProfileData)
3908       NameVals.push_back(static_cast<uint8_t>(ECI.second.Hotness));
3909     else if (WriteRelBFToSummary)
3910       NameVals.push_back(ECI.second.RelBlockFreq);
3911   }
3912 
3913   unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
3914   unsigned Code =
3915       (HasProfileData ? bitc::FS_PERMODULE_PROFILE
3916                       : (WriteRelBFToSummary ? bitc::FS_PERMODULE_RELBF
3917                                              : bitc::FS_PERMODULE));
3918 
3919   // Emit the finished record.
3920   Stream.EmitRecord(Code, NameVals, FSAbbrev);
3921   NameVals.clear();
3922 }
3923 
3924 // Collect the global value references in the given variable's initializer,
3925 // and emit them in a summary record.
3926 void ModuleBitcodeWriterBase::writeModuleLevelReferences(
3927     const GlobalVariable &V, SmallVector<uint64_t, 64> &NameVals,
3928     unsigned FSModRefsAbbrev, unsigned FSModVTableRefsAbbrev) {
3929   auto VI = Index->getValueInfo(V.getGUID());
3930   if (!VI || VI.getSummaryList().empty()) {
3931     // Only declarations should not have a summary (a declaration might however
3932     // have a summary if the def was in module level asm).
3933     assert(V.isDeclaration());
3934     return;
3935   }
3936   auto *Summary = VI.getSummaryList()[0].get();
3937   NameVals.push_back(VE.getValueID(&V));
3938   GlobalVarSummary *VS = cast<GlobalVarSummary>(Summary);
3939   NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
3940   NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
3941 
3942   auto VTableFuncs = VS->vTableFuncs();
3943   if (!VTableFuncs.empty())
3944     NameVals.push_back(VS->refs().size());
3945 
3946   unsigned SizeBeforeRefs = NameVals.size();
3947   for (auto &RI : VS->refs())
3948     NameVals.push_back(VE.getValueID(RI.getValue()));
3949   // Sort the refs for determinism output, the vector returned by FS->refs() has
3950   // been initialized from a DenseSet.
3951   llvm::sort(drop_begin(NameVals, SizeBeforeRefs));
3952 
3953   if (VTableFuncs.empty())
3954     Stream.EmitRecord(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS, NameVals,
3955                       FSModRefsAbbrev);
3956   else {
3957     // VTableFuncs pairs should already be sorted by offset.
3958     for (auto &P : VTableFuncs) {
3959       NameVals.push_back(VE.getValueID(P.FuncVI.getValue()));
3960       NameVals.push_back(P.VTableOffset);
3961     }
3962 
3963     Stream.EmitRecord(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS, NameVals,
3964                       FSModVTableRefsAbbrev);
3965   }
3966   NameVals.clear();
3967 }
3968 
3969 /// Emit the per-module summary section alongside the rest of
3970 /// the module's bitcode.
3971 void ModuleBitcodeWriterBase::writePerModuleGlobalValueSummary() {
3972   // By default we compile with ThinLTO if the module has a summary, but the
3973   // client can request full LTO with a module flag.
3974   bool IsThinLTO = true;
3975   if (auto *MD =
3976           mdconst::extract_or_null<ConstantInt>(M.getModuleFlag("ThinLTO")))
3977     IsThinLTO = MD->getZExtValue();
3978   Stream.EnterSubblock(IsThinLTO ? bitc::GLOBALVAL_SUMMARY_BLOCK_ID
3979                                  : bitc::FULL_LTO_GLOBALVAL_SUMMARY_BLOCK_ID,
3980                        4);
3981 
3982   Stream.EmitRecord(
3983       bitc::FS_VERSION,
3984       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
3985 
3986   // Write the index flags.
3987   uint64_t Flags = 0;
3988   // Bits 1-3 are set only in the combined index, skip them.
3989   if (Index->enableSplitLTOUnit())
3990     Flags |= 0x8;
3991   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Flags});
3992 
3993   if (Index->begin() == Index->end()) {
3994     Stream.ExitBlock();
3995     return;
3996   }
3997 
3998   for (const auto &GVI : valueIds()) {
3999     Stream.EmitRecord(bitc::FS_VALUE_GUID,
4000                       ArrayRef<uint64_t>{GVI.second, GVI.first});
4001   }
4002 
4003   // Abbrev for FS_PERMODULE_PROFILE.
4004   auto Abbv = std::make_shared<BitCodeAbbrev>();
4005   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_PROFILE));
4006   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4007   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4008   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4009   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4010   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4011   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4012   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4013   // numrefs x valueid, n x (valueid, hotness)
4014   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4015   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4016   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4017 
4018   // Abbrev for FS_PERMODULE or FS_PERMODULE_RELBF.
4019   Abbv = std::make_shared<BitCodeAbbrev>();
4020   if (WriteRelBFToSummary)
4021     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_RELBF));
4022   else
4023     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE));
4024   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4025   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4026   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4027   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4028   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4029   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4030   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4031   // numrefs x valueid, n x (valueid [, rel_block_freq])
4032   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4033   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4034   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4035 
4036   // Abbrev for FS_PERMODULE_GLOBALVAR_INIT_REFS.
4037   Abbv = std::make_shared<BitCodeAbbrev>();
4038   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS));
4039   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
4040   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
4041   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));  // valueids
4042   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4043   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4044 
4045   // Abbrev for FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS.
4046   Abbv = std::make_shared<BitCodeAbbrev>();
4047   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS));
4048   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
4049   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
4050   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numrefs
4051   // numrefs x valueid, n x (valueid , offset)
4052   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4053   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4054   unsigned FSModVTableRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4055 
4056   // Abbrev for FS_ALIAS.
4057   Abbv = std::make_shared<BitCodeAbbrev>();
4058   Abbv->Add(BitCodeAbbrevOp(bitc::FS_ALIAS));
4059   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4060   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4061   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4062   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4063 
4064   // Abbrev for FS_TYPE_ID_METADATA
4065   Abbv = std::make_shared<BitCodeAbbrev>();
4066   Abbv->Add(BitCodeAbbrevOp(bitc::FS_TYPE_ID_METADATA));
4067   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid strtab index
4068   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid length
4069   // n x (valueid , offset)
4070   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4071   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4072   unsigned TypeIdCompatibleVtableAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4073 
4074   SmallVector<uint64_t, 64> NameVals;
4075   // Iterate over the list of functions instead of the Index to
4076   // ensure the ordering is stable.
4077   for (const Function &F : M) {
4078     // Summary emission does not support anonymous functions, they have to
4079     // renamed using the anonymous function renaming pass.
4080     if (!F.hasName())
4081       report_fatal_error("Unexpected anonymous function when writing summary");
4082 
4083     ValueInfo VI = Index->getValueInfo(F.getGUID());
4084     if (!VI || VI.getSummaryList().empty()) {
4085       // Only declarations should not have a summary (a declaration might
4086       // however have a summary if the def was in module level asm).
4087       assert(F.isDeclaration());
4088       continue;
4089     }
4090     auto *Summary = VI.getSummaryList()[0].get();
4091     writePerModuleFunctionSummaryRecord(NameVals, Summary, VE.getValueID(&F),
4092                                         FSCallsAbbrev, FSCallsProfileAbbrev, F);
4093   }
4094 
4095   // Capture references from GlobalVariable initializers, which are outside
4096   // of a function scope.
4097   for (const GlobalVariable &G : M.globals())
4098     writeModuleLevelReferences(G, NameVals, FSModRefsAbbrev,
4099                                FSModVTableRefsAbbrev);
4100 
4101   for (const GlobalAlias &A : M.aliases()) {
4102     auto *Aliasee = A.getAliaseeObject();
4103     if (!Aliasee->hasName())
4104       // Nameless function don't have an entry in the summary, skip it.
4105       continue;
4106     auto AliasId = VE.getValueID(&A);
4107     auto AliaseeId = VE.getValueID(Aliasee);
4108     NameVals.push_back(AliasId);
4109     auto *Summary = Index->getGlobalValueSummary(A);
4110     AliasSummary *AS = cast<AliasSummary>(Summary);
4111     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
4112     NameVals.push_back(AliaseeId);
4113     Stream.EmitRecord(bitc::FS_ALIAS, NameVals, FSAliasAbbrev);
4114     NameVals.clear();
4115   }
4116 
4117   for (auto &S : Index->typeIdCompatibleVtableMap()) {
4118     writeTypeIdCompatibleVtableSummaryRecord(NameVals, StrtabBuilder, S.first,
4119                                              S.second, VE);
4120     Stream.EmitRecord(bitc::FS_TYPE_ID_METADATA, NameVals,
4121                       TypeIdCompatibleVtableAbbrev);
4122     NameVals.clear();
4123   }
4124 
4125   Stream.EmitRecord(bitc::FS_BLOCK_COUNT,
4126                     ArrayRef<uint64_t>{Index->getBlockCount()});
4127 
4128   Stream.ExitBlock();
4129 }
4130 
4131 /// Emit the combined summary section into the combined index file.
4132 void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
4133   Stream.EnterSubblock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID, 3);
4134   Stream.EmitRecord(
4135       bitc::FS_VERSION,
4136       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
4137 
4138   // Write the index flags.
4139   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Index.getFlags()});
4140 
4141   for (const auto &GVI : valueIds()) {
4142     Stream.EmitRecord(bitc::FS_VALUE_GUID,
4143                       ArrayRef<uint64_t>{GVI.second, GVI.first});
4144   }
4145 
4146   // Abbrev for FS_COMBINED.
4147   auto Abbv = std::make_shared<BitCodeAbbrev>();
4148   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED));
4149   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4150   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4151   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4152   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4153   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4154   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
4155   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4156   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4157   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4158   // numrefs x valueid, n x (valueid)
4159   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4160   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4161   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4162 
4163   // Abbrev for FS_COMBINED_PROFILE.
4164   Abbv = std::make_shared<BitCodeAbbrev>();
4165   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_PROFILE));
4166   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4167   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4168   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4169   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4170   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4171   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
4172   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4173   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4174   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4175   // numrefs x valueid, n x (valueid, hotness)
4176   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4177   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4178   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4179 
4180   // Abbrev for FS_COMBINED_GLOBALVAR_INIT_REFS.
4181   Abbv = std::make_shared<BitCodeAbbrev>();
4182   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS));
4183   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4184   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4185   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4186   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));    // valueids
4187   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4188   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4189 
4190   // Abbrev for FS_COMBINED_ALIAS.
4191   Abbv = std::make_shared<BitCodeAbbrev>();
4192   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_ALIAS));
4193   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4194   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4195   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4196   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4197   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4198 
4199   // The aliases are emitted as a post-pass, and will point to the value
4200   // id of the aliasee. Save them in a vector for post-processing.
4201   SmallVector<AliasSummary *, 64> Aliases;
4202 
4203   // Save the value id for each summary for alias emission.
4204   DenseMap<const GlobalValueSummary *, unsigned> SummaryToValueIdMap;
4205 
4206   SmallVector<uint64_t, 64> NameVals;
4207 
4208   // Set that will be populated during call to writeFunctionTypeMetadataRecords
4209   // with the type ids referenced by this index file.
4210   std::set<GlobalValue::GUID> ReferencedTypeIds;
4211 
4212   // For local linkage, we also emit the original name separately
4213   // immediately after the record.
4214   auto MaybeEmitOriginalName = [&](GlobalValueSummary &S) {
4215     // We don't need to emit the original name if we are writing the index for
4216     // distributed backends (in which case ModuleToSummariesForIndex is
4217     // non-null). The original name is only needed during the thin link, since
4218     // for SamplePGO the indirect call targets for local functions have
4219     // have the original name annotated in profile.
4220     // Continue to emit it when writing out the entire combined index, which is
4221     // used in testing the thin link via llvm-lto.
4222     if (ModuleToSummariesForIndex || !GlobalValue::isLocalLinkage(S.linkage()))
4223       return;
4224     NameVals.push_back(S.getOriginalName());
4225     Stream.EmitRecord(bitc::FS_COMBINED_ORIGINAL_NAME, NameVals);
4226     NameVals.clear();
4227   };
4228 
4229   std::set<GlobalValue::GUID> DefOrUseGUIDs;
4230   forEachSummary([&](GVInfo I, bool IsAliasee) {
4231     GlobalValueSummary *S = I.second;
4232     assert(S);
4233     DefOrUseGUIDs.insert(I.first);
4234     for (const ValueInfo &VI : S->refs())
4235       DefOrUseGUIDs.insert(VI.getGUID());
4236 
4237     auto ValueId = getValueId(I.first);
4238     assert(ValueId);
4239     SummaryToValueIdMap[S] = *ValueId;
4240 
4241     // If this is invoked for an aliasee, we want to record the above
4242     // mapping, but then not emit a summary entry (if the aliasee is
4243     // to be imported, we will invoke this separately with IsAliasee=false).
4244     if (IsAliasee)
4245       return;
4246 
4247     if (auto *AS = dyn_cast<AliasSummary>(S)) {
4248       // Will process aliases as a post-pass because the reader wants all
4249       // global to be loaded first.
4250       Aliases.push_back(AS);
4251       return;
4252     }
4253 
4254     if (auto *VS = dyn_cast<GlobalVarSummary>(S)) {
4255       NameVals.push_back(*ValueId);
4256       NameVals.push_back(Index.getModuleId(VS->modulePath()));
4257       NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
4258       NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
4259       for (auto &RI : VS->refs()) {
4260         auto RefValueId = getValueId(RI.getGUID());
4261         if (!RefValueId)
4262           continue;
4263         NameVals.push_back(*RefValueId);
4264       }
4265 
4266       // Emit the finished record.
4267       Stream.EmitRecord(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS, NameVals,
4268                         FSModRefsAbbrev);
4269       NameVals.clear();
4270       MaybeEmitOriginalName(*S);
4271       return;
4272     }
4273 
4274     auto GetValueId = [&](const ValueInfo &VI) -> Optional<unsigned> {
4275       return getValueId(VI.getGUID());
4276     };
4277 
4278     auto *FS = cast<FunctionSummary>(S);
4279     writeFunctionTypeMetadataRecords(Stream, FS, GetValueId);
4280     getReferencedTypeIds(FS, ReferencedTypeIds);
4281 
4282     NameVals.push_back(*ValueId);
4283     NameVals.push_back(Index.getModuleId(FS->modulePath()));
4284     NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
4285     NameVals.push_back(FS->instCount());
4286     NameVals.push_back(getEncodedFFlags(FS->fflags()));
4287     NameVals.push_back(FS->entryCount());
4288 
4289     // Fill in below
4290     NameVals.push_back(0); // numrefs
4291     NameVals.push_back(0); // rorefcnt
4292     NameVals.push_back(0); // worefcnt
4293 
4294     unsigned Count = 0, RORefCnt = 0, WORefCnt = 0;
4295     for (auto &RI : FS->refs()) {
4296       auto RefValueId = getValueId(RI.getGUID());
4297       if (!RefValueId)
4298         continue;
4299       NameVals.push_back(*RefValueId);
4300       if (RI.isReadOnly())
4301         RORefCnt++;
4302       else if (RI.isWriteOnly())
4303         WORefCnt++;
4304       Count++;
4305     }
4306     NameVals[6] = Count;
4307     NameVals[7] = RORefCnt;
4308     NameVals[8] = WORefCnt;
4309 
4310     bool HasProfileData = false;
4311     for (auto &EI : FS->calls()) {
4312       HasProfileData |=
4313           EI.second.getHotness() != CalleeInfo::HotnessType::Unknown;
4314       if (HasProfileData)
4315         break;
4316     }
4317 
4318     for (auto &EI : FS->calls()) {
4319       // If this GUID doesn't have a value id, it doesn't have a function
4320       // summary and we don't need to record any calls to it.
4321       Optional<unsigned> CallValueId = GetValueId(EI.first);
4322       if (!CallValueId)
4323         continue;
4324       NameVals.push_back(*CallValueId);
4325       if (HasProfileData)
4326         NameVals.push_back(static_cast<uint8_t>(EI.second.Hotness));
4327     }
4328 
4329     unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
4330     unsigned Code =
4331         (HasProfileData ? bitc::FS_COMBINED_PROFILE : bitc::FS_COMBINED);
4332 
4333     // Emit the finished record.
4334     Stream.EmitRecord(Code, NameVals, FSAbbrev);
4335     NameVals.clear();
4336     MaybeEmitOriginalName(*S);
4337   });
4338 
4339   for (auto *AS : Aliases) {
4340     auto AliasValueId = SummaryToValueIdMap[AS];
4341     assert(AliasValueId);
4342     NameVals.push_back(AliasValueId);
4343     NameVals.push_back(Index.getModuleId(AS->modulePath()));
4344     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
4345     auto AliaseeValueId = SummaryToValueIdMap[&AS->getAliasee()];
4346     assert(AliaseeValueId);
4347     NameVals.push_back(AliaseeValueId);
4348 
4349     // Emit the finished record.
4350     Stream.EmitRecord(bitc::FS_COMBINED_ALIAS, NameVals, FSAliasAbbrev);
4351     NameVals.clear();
4352     MaybeEmitOriginalName(*AS);
4353 
4354     if (auto *FS = dyn_cast<FunctionSummary>(&AS->getAliasee()))
4355       getReferencedTypeIds(FS, ReferencedTypeIds);
4356   }
4357 
4358   if (!Index.cfiFunctionDefs().empty()) {
4359     for (auto &S : Index.cfiFunctionDefs()) {
4360       if (DefOrUseGUIDs.count(
4361               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4362         NameVals.push_back(StrtabBuilder.add(S));
4363         NameVals.push_back(S.size());
4364       }
4365     }
4366     if (!NameVals.empty()) {
4367       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DEFS, NameVals);
4368       NameVals.clear();
4369     }
4370   }
4371 
4372   if (!Index.cfiFunctionDecls().empty()) {
4373     for (auto &S : Index.cfiFunctionDecls()) {
4374       if (DefOrUseGUIDs.count(
4375               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4376         NameVals.push_back(StrtabBuilder.add(S));
4377         NameVals.push_back(S.size());
4378       }
4379     }
4380     if (!NameVals.empty()) {
4381       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DECLS, NameVals);
4382       NameVals.clear();
4383     }
4384   }
4385 
4386   // Walk the GUIDs that were referenced, and write the
4387   // corresponding type id records.
4388   for (auto &T : ReferencedTypeIds) {
4389     auto TidIter = Index.typeIds().equal_range(T);
4390     for (auto It = TidIter.first; It != TidIter.second; ++It) {
4391       writeTypeIdSummaryRecord(NameVals, StrtabBuilder, It->second.first,
4392                                It->second.second);
4393       Stream.EmitRecord(bitc::FS_TYPE_ID, NameVals);
4394       NameVals.clear();
4395     }
4396   }
4397 
4398   Stream.EmitRecord(bitc::FS_BLOCK_COUNT,
4399                     ArrayRef<uint64_t>{Index.getBlockCount()});
4400 
4401   Stream.ExitBlock();
4402 }
4403 
4404 /// Create the "IDENTIFICATION_BLOCK_ID" containing a single string with the
4405 /// current llvm version, and a record for the epoch number.
4406 static void writeIdentificationBlock(BitstreamWriter &Stream) {
4407   Stream.EnterSubblock(bitc::IDENTIFICATION_BLOCK_ID, 5);
4408 
4409   // Write the "user readable" string identifying the bitcode producer
4410   auto Abbv = std::make_shared<BitCodeAbbrev>();
4411   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_STRING));
4412   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4413   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
4414   auto StringAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4415   writeStringRecord(Stream, bitc::IDENTIFICATION_CODE_STRING,
4416                     "LLVM" LLVM_VERSION_STRING, StringAbbrev);
4417 
4418   // Write the epoch version
4419   Abbv = std::make_shared<BitCodeAbbrev>();
4420   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_EPOCH));
4421   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
4422   auto EpochAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4423   constexpr std::array<unsigned, 1> Vals = {{bitc::BITCODE_CURRENT_EPOCH}};
4424   Stream.EmitRecord(bitc::IDENTIFICATION_CODE_EPOCH, Vals, EpochAbbrev);
4425   Stream.ExitBlock();
4426 }
4427 
4428 void ModuleBitcodeWriter::writeModuleHash(size_t BlockStartPos) {
4429   // Emit the module's hash.
4430   // MODULE_CODE_HASH: [5*i32]
4431   if (GenerateHash) {
4432     uint32_t Vals[5];
4433     Hasher.update(ArrayRef<uint8_t>((const uint8_t *)&(Buffer)[BlockStartPos],
4434                                     Buffer.size() - BlockStartPos));
4435     std::array<uint8_t, 20> Hash = Hasher.result();
4436     for (int Pos = 0; Pos < 20; Pos += 4) {
4437       Vals[Pos / 4] = support::endian::read32be(Hash.data() + Pos);
4438     }
4439 
4440     // Emit the finished record.
4441     Stream.EmitRecord(bitc::MODULE_CODE_HASH, Vals);
4442 
4443     if (ModHash)
4444       // Save the written hash value.
4445       llvm::copy(Vals, std::begin(*ModHash));
4446   }
4447 }
4448 
4449 void ModuleBitcodeWriter::write() {
4450   writeIdentificationBlock(Stream);
4451 
4452   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4453   size_t BlockStartPos = Buffer.size();
4454 
4455   writeModuleVersion();
4456 
4457   // Emit blockinfo, which defines the standard abbreviations etc.
4458   writeBlockInfo();
4459 
4460   // Emit information describing all of the types in the module.
4461   writeTypeTable();
4462 
4463   // Emit information about attribute groups.
4464   writeAttributeGroupTable();
4465 
4466   // Emit information about parameter attributes.
4467   writeAttributeTable();
4468 
4469   writeComdats();
4470 
4471   // Emit top-level description of module, including target triple, inline asm,
4472   // descriptors for global variables, and function prototype info.
4473   writeModuleInfo();
4474 
4475   // Emit constants.
4476   writeModuleConstants();
4477 
4478   // Emit metadata kind names.
4479   writeModuleMetadataKinds();
4480 
4481   // Emit metadata.
4482   writeModuleMetadata();
4483 
4484   // Emit module-level use-lists.
4485   if (VE.shouldPreserveUseListOrder())
4486     writeUseListBlock(nullptr);
4487 
4488   writeOperandBundleTags();
4489   writeSyncScopeNames();
4490 
4491   // Emit function bodies.
4492   DenseMap<const Function *, uint64_t> FunctionToBitcodeIndex;
4493   for (const Function &F : M)
4494     if (!F.isDeclaration())
4495       writeFunction(F, FunctionToBitcodeIndex);
4496 
4497   // Need to write after the above call to WriteFunction which populates
4498   // the summary information in the index.
4499   if (Index)
4500     writePerModuleGlobalValueSummary();
4501 
4502   writeGlobalValueSymbolTable(FunctionToBitcodeIndex);
4503 
4504   writeModuleHash(BlockStartPos);
4505 
4506   Stream.ExitBlock();
4507 }
4508 
4509 static void writeInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
4510                                uint32_t &Position) {
4511   support::endian::write32le(&Buffer[Position], Value);
4512   Position += 4;
4513 }
4514 
4515 /// If generating a bc file on darwin, we have to emit a
4516 /// header and trailer to make it compatible with the system archiver.  To do
4517 /// this we emit the following header, and then emit a trailer that pads the
4518 /// file out to be a multiple of 16 bytes.
4519 ///
4520 /// struct bc_header {
4521 ///   uint32_t Magic;         // 0x0B17C0DE
4522 ///   uint32_t Version;       // Version, currently always 0.
4523 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
4524 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
4525 ///   uint32_t CPUType;       // CPU specifier.
4526 ///   ... potentially more later ...
4527 /// };
4528 static void emitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
4529                                          const Triple &TT) {
4530   unsigned CPUType = ~0U;
4531 
4532   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
4533   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
4534   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
4535   // specific constants here because they are implicitly part of the Darwin ABI.
4536   enum {
4537     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
4538     DARWIN_CPU_TYPE_X86        = 7,
4539     DARWIN_CPU_TYPE_ARM        = 12,
4540     DARWIN_CPU_TYPE_POWERPC    = 18
4541   };
4542 
4543   Triple::ArchType Arch = TT.getArch();
4544   if (Arch == Triple::x86_64)
4545     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
4546   else if (Arch == Triple::x86)
4547     CPUType = DARWIN_CPU_TYPE_X86;
4548   else if (Arch == Triple::ppc)
4549     CPUType = DARWIN_CPU_TYPE_POWERPC;
4550   else if (Arch == Triple::ppc64)
4551     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
4552   else if (Arch == Triple::arm || Arch == Triple::thumb)
4553     CPUType = DARWIN_CPU_TYPE_ARM;
4554 
4555   // Traditional Bitcode starts after header.
4556   assert(Buffer.size() >= BWH_HeaderSize &&
4557          "Expected header size to be reserved");
4558   unsigned BCOffset = BWH_HeaderSize;
4559   unsigned BCSize = Buffer.size() - BWH_HeaderSize;
4560 
4561   // Write the magic and version.
4562   unsigned Position = 0;
4563   writeInt32ToBuffer(0x0B17C0DE, Buffer, Position);
4564   writeInt32ToBuffer(0, Buffer, Position); // Version.
4565   writeInt32ToBuffer(BCOffset, Buffer, Position);
4566   writeInt32ToBuffer(BCSize, Buffer, Position);
4567   writeInt32ToBuffer(CPUType, Buffer, Position);
4568 
4569   // If the file is not a multiple of 16 bytes, insert dummy padding.
4570   while (Buffer.size() & 15)
4571     Buffer.push_back(0);
4572 }
4573 
4574 /// Helper to write the header common to all bitcode files.
4575 static void writeBitcodeHeader(BitstreamWriter &Stream) {
4576   // Emit the file header.
4577   Stream.Emit((unsigned)'B', 8);
4578   Stream.Emit((unsigned)'C', 8);
4579   Stream.Emit(0x0, 4);
4580   Stream.Emit(0xC, 4);
4581   Stream.Emit(0xE, 4);
4582   Stream.Emit(0xD, 4);
4583 }
4584 
4585 BitcodeWriter::BitcodeWriter(SmallVectorImpl<char> &Buffer, raw_fd_stream *FS)
4586     : Buffer(Buffer), Stream(new BitstreamWriter(Buffer, FS, FlushThreshold)) {
4587   writeBitcodeHeader(*Stream);
4588 }
4589 
4590 BitcodeWriter::~BitcodeWriter() { assert(WroteStrtab); }
4591 
4592 void BitcodeWriter::writeBlob(unsigned Block, unsigned Record, StringRef Blob) {
4593   Stream->EnterSubblock(Block, 3);
4594 
4595   auto Abbv = std::make_shared<BitCodeAbbrev>();
4596   Abbv->Add(BitCodeAbbrevOp(Record));
4597   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
4598   auto AbbrevNo = Stream->EmitAbbrev(std::move(Abbv));
4599 
4600   Stream->EmitRecordWithBlob(AbbrevNo, ArrayRef<uint64_t>{Record}, Blob);
4601 
4602   Stream->ExitBlock();
4603 }
4604 
4605 void BitcodeWriter::writeSymtab() {
4606   assert(!WroteStrtab && !WroteSymtab);
4607 
4608   // If any module has module-level inline asm, we will require a registered asm
4609   // parser for the target so that we can create an accurate symbol table for
4610   // the module.
4611   for (Module *M : Mods) {
4612     if (M->getModuleInlineAsm().empty())
4613       continue;
4614 
4615     std::string Err;
4616     const Triple TT(M->getTargetTriple());
4617     const Target *T = TargetRegistry::lookupTarget(TT.str(), Err);
4618     if (!T || !T->hasMCAsmParser())
4619       return;
4620   }
4621 
4622   WroteSymtab = true;
4623   SmallVector<char, 0> Symtab;
4624   // The irsymtab::build function may be unable to create a symbol table if the
4625   // module is malformed (e.g. it contains an invalid alias). Writing a symbol
4626   // table is not required for correctness, but we still want to be able to
4627   // write malformed modules to bitcode files, so swallow the error.
4628   if (Error E = irsymtab::build(Mods, Symtab, StrtabBuilder, Alloc)) {
4629     consumeError(std::move(E));
4630     return;
4631   }
4632 
4633   writeBlob(bitc::SYMTAB_BLOCK_ID, bitc::SYMTAB_BLOB,
4634             {Symtab.data(), Symtab.size()});
4635 }
4636 
4637 void BitcodeWriter::writeStrtab() {
4638   assert(!WroteStrtab);
4639 
4640   std::vector<char> Strtab;
4641   StrtabBuilder.finalizeInOrder();
4642   Strtab.resize(StrtabBuilder.getSize());
4643   StrtabBuilder.write((uint8_t *)Strtab.data());
4644 
4645   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB,
4646             {Strtab.data(), Strtab.size()});
4647 
4648   WroteStrtab = true;
4649 }
4650 
4651 void BitcodeWriter::copyStrtab(StringRef Strtab) {
4652   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB, Strtab);
4653   WroteStrtab = true;
4654 }
4655 
4656 void BitcodeWriter::writeModule(const Module &M,
4657                                 bool ShouldPreserveUseListOrder,
4658                                 const ModuleSummaryIndex *Index,
4659                                 bool GenerateHash, ModuleHash *ModHash) {
4660   assert(!WroteStrtab);
4661 
4662   // The Mods vector is used by irsymtab::build, which requires non-const
4663   // Modules in case it needs to materialize metadata. But the bitcode writer
4664   // requires that the module is materialized, so we can cast to non-const here,
4665   // after checking that it is in fact materialized.
4666   assert(M.isMaterialized());
4667   Mods.push_back(const_cast<Module *>(&M));
4668 
4669   ModuleBitcodeWriter ModuleWriter(M, Buffer, StrtabBuilder, *Stream,
4670                                    ShouldPreserveUseListOrder, Index,
4671                                    GenerateHash, ModHash);
4672   ModuleWriter.write();
4673 }
4674 
4675 void BitcodeWriter::writeIndex(
4676     const ModuleSummaryIndex *Index,
4677     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4678   IndexBitcodeWriter IndexWriter(*Stream, StrtabBuilder, *Index,
4679                                  ModuleToSummariesForIndex);
4680   IndexWriter.write();
4681 }
4682 
4683 /// Write the specified module to the specified output stream.
4684 void llvm::WriteBitcodeToFile(const Module &M, raw_ostream &Out,
4685                               bool ShouldPreserveUseListOrder,
4686                               const ModuleSummaryIndex *Index,
4687                               bool GenerateHash, ModuleHash *ModHash) {
4688   SmallVector<char, 0> Buffer;
4689   Buffer.reserve(256*1024);
4690 
4691   // If this is darwin or another generic macho target, reserve space for the
4692   // header.
4693   Triple TT(M.getTargetTriple());
4694   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4695     Buffer.insert(Buffer.begin(), BWH_HeaderSize, 0);
4696 
4697   BitcodeWriter Writer(Buffer, dyn_cast<raw_fd_stream>(&Out));
4698   Writer.writeModule(M, ShouldPreserveUseListOrder, Index, GenerateHash,
4699                      ModHash);
4700   Writer.writeSymtab();
4701   Writer.writeStrtab();
4702 
4703   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4704     emitDarwinBCHeaderAndTrailer(Buffer, TT);
4705 
4706   // Write the generated bitstream to "Out".
4707   if (!Buffer.empty())
4708     Out.write((char *)&Buffer.front(), Buffer.size());
4709 }
4710 
4711 void IndexBitcodeWriter::write() {
4712   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4713 
4714   writeModuleVersion();
4715 
4716   // Write the module paths in the combined index.
4717   writeModStrings();
4718 
4719   // Write the summary combined index records.
4720   writeCombinedGlobalValueSummary();
4721 
4722   Stream.ExitBlock();
4723 }
4724 
4725 // Write the specified module summary index to the given raw output stream,
4726 // where it will be written in a new bitcode block. This is used when
4727 // writing the combined index file for ThinLTO. When writing a subset of the
4728 // index for a distributed backend, provide a \p ModuleToSummariesForIndex map.
4729 void llvm::writeIndexToFile(
4730     const ModuleSummaryIndex &Index, raw_ostream &Out,
4731     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4732   SmallVector<char, 0> Buffer;
4733   Buffer.reserve(256 * 1024);
4734 
4735   BitcodeWriter Writer(Buffer);
4736   Writer.writeIndex(&Index, ModuleToSummariesForIndex);
4737   Writer.writeStrtab();
4738 
4739   Out.write((char *)&Buffer.front(), Buffer.size());
4740 }
4741 
4742 namespace {
4743 
4744 /// Class to manage the bitcode writing for a thin link bitcode file.
4745 class ThinLinkBitcodeWriter : public ModuleBitcodeWriterBase {
4746   /// ModHash is for use in ThinLTO incremental build, generated while writing
4747   /// the module bitcode file.
4748   const ModuleHash *ModHash;
4749 
4750 public:
4751   ThinLinkBitcodeWriter(const Module &M, StringTableBuilder &StrtabBuilder,
4752                         BitstreamWriter &Stream,
4753                         const ModuleSummaryIndex &Index,
4754                         const ModuleHash &ModHash)
4755       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
4756                                 /*ShouldPreserveUseListOrder=*/false, &Index),
4757         ModHash(&ModHash) {}
4758 
4759   void write();
4760 
4761 private:
4762   void writeSimplifiedModuleInfo();
4763 };
4764 
4765 } // end anonymous namespace
4766 
4767 // This function writes a simpilified module info for thin link bitcode file.
4768 // It only contains the source file name along with the name(the offset and
4769 // size in strtab) and linkage for global values. For the global value info
4770 // entry, in order to keep linkage at offset 5, there are three zeros used
4771 // as padding.
4772 void ThinLinkBitcodeWriter::writeSimplifiedModuleInfo() {
4773   SmallVector<unsigned, 64> Vals;
4774   // Emit the module's source file name.
4775   {
4776     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
4777     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
4778     if (Bits == SE_Char6)
4779       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
4780     else if (Bits == SE_Fixed7)
4781       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
4782 
4783     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
4784     auto Abbv = std::make_shared<BitCodeAbbrev>();
4785     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
4786     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4787     Abbv->Add(AbbrevOpToUse);
4788     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4789 
4790     for (const auto P : M.getSourceFileName())
4791       Vals.push_back((unsigned char)P);
4792 
4793     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
4794     Vals.clear();
4795   }
4796 
4797   // Emit the global variable information.
4798   for (const GlobalVariable &GV : M.globals()) {
4799     // GLOBALVAR: [strtab offset, strtab size, 0, 0, 0, linkage]
4800     Vals.push_back(StrtabBuilder.add(GV.getName()));
4801     Vals.push_back(GV.getName().size());
4802     Vals.push_back(0);
4803     Vals.push_back(0);
4804     Vals.push_back(0);
4805     Vals.push_back(getEncodedLinkage(GV));
4806 
4807     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals);
4808     Vals.clear();
4809   }
4810 
4811   // Emit the function proto information.
4812   for (const Function &F : M) {
4813     // FUNCTION:  [strtab offset, strtab size, 0, 0, 0, linkage]
4814     Vals.push_back(StrtabBuilder.add(F.getName()));
4815     Vals.push_back(F.getName().size());
4816     Vals.push_back(0);
4817     Vals.push_back(0);
4818     Vals.push_back(0);
4819     Vals.push_back(getEncodedLinkage(F));
4820 
4821     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals);
4822     Vals.clear();
4823   }
4824 
4825   // Emit the alias information.
4826   for (const GlobalAlias &A : M.aliases()) {
4827     // ALIAS: [strtab offset, strtab size, 0, 0, 0, linkage]
4828     Vals.push_back(StrtabBuilder.add(A.getName()));
4829     Vals.push_back(A.getName().size());
4830     Vals.push_back(0);
4831     Vals.push_back(0);
4832     Vals.push_back(0);
4833     Vals.push_back(getEncodedLinkage(A));
4834 
4835     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals);
4836     Vals.clear();
4837   }
4838 
4839   // Emit the ifunc information.
4840   for (const GlobalIFunc &I : M.ifuncs()) {
4841     // IFUNC: [strtab offset, strtab size, 0, 0, 0, linkage]
4842     Vals.push_back(StrtabBuilder.add(I.getName()));
4843     Vals.push_back(I.getName().size());
4844     Vals.push_back(0);
4845     Vals.push_back(0);
4846     Vals.push_back(0);
4847     Vals.push_back(getEncodedLinkage(I));
4848 
4849     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
4850     Vals.clear();
4851   }
4852 }
4853 
4854 void ThinLinkBitcodeWriter::write() {
4855   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4856 
4857   writeModuleVersion();
4858 
4859   writeSimplifiedModuleInfo();
4860 
4861   writePerModuleGlobalValueSummary();
4862 
4863   // Write module hash.
4864   Stream.EmitRecord(bitc::MODULE_CODE_HASH, ArrayRef<uint32_t>(*ModHash));
4865 
4866   Stream.ExitBlock();
4867 }
4868 
4869 void BitcodeWriter::writeThinLinkBitcode(const Module &M,
4870                                          const ModuleSummaryIndex &Index,
4871                                          const ModuleHash &ModHash) {
4872   assert(!WroteStrtab);
4873 
4874   // The Mods vector is used by irsymtab::build, which requires non-const
4875   // Modules in case it needs to materialize metadata. But the bitcode writer
4876   // requires that the module is materialized, so we can cast to non-const here,
4877   // after checking that it is in fact materialized.
4878   assert(M.isMaterialized());
4879   Mods.push_back(const_cast<Module *>(&M));
4880 
4881   ThinLinkBitcodeWriter ThinLinkWriter(M, StrtabBuilder, *Stream, Index,
4882                                        ModHash);
4883   ThinLinkWriter.write();
4884 }
4885 
4886 // Write the specified thin link bitcode file to the given raw output stream,
4887 // where it will be written in a new bitcode block. This is used when
4888 // writing the per-module index file for ThinLTO.
4889 void llvm::writeThinLinkBitcodeToFile(const Module &M, raw_ostream &Out,
4890                                       const ModuleSummaryIndex &Index,
4891                                       const ModuleHash &ModHash) {
4892   SmallVector<char, 0> Buffer;
4893   Buffer.reserve(256 * 1024);
4894 
4895   BitcodeWriter Writer(Buffer);
4896   Writer.writeThinLinkBitcode(M, Index, ModHash);
4897   Writer.writeSymtab();
4898   Writer.writeStrtab();
4899 
4900   Out.write((char *)&Buffer.front(), Buffer.size());
4901 }
4902 
4903 static const char *getSectionNameForBitcode(const Triple &T) {
4904   switch (T.getObjectFormat()) {
4905   case Triple::MachO:
4906     return "__LLVM,__bitcode";
4907   case Triple::COFF:
4908   case Triple::ELF:
4909   case Triple::Wasm:
4910   case Triple::UnknownObjectFormat:
4911     return ".llvmbc";
4912   case Triple::GOFF:
4913     llvm_unreachable("GOFF is not yet implemented");
4914     break;
4915   case Triple::SPIRV:
4916     llvm_unreachable("SPIRV is not yet implemented");
4917     break;
4918   case Triple::XCOFF:
4919     llvm_unreachable("XCOFF is not yet implemented");
4920     break;
4921   case Triple::DXContainer:
4922     llvm_unreachable("DXContainer is not yet implemented");
4923     break;
4924   }
4925   llvm_unreachable("Unimplemented ObjectFormatType");
4926 }
4927 
4928 static const char *getSectionNameForCommandline(const Triple &T) {
4929   switch (T.getObjectFormat()) {
4930   case Triple::MachO:
4931     return "__LLVM,__cmdline";
4932   case Triple::COFF:
4933   case Triple::ELF:
4934   case Triple::Wasm:
4935   case Triple::UnknownObjectFormat:
4936     return ".llvmcmd";
4937   case Triple::GOFF:
4938     llvm_unreachable("GOFF is not yet implemented");
4939     break;
4940   case Triple::SPIRV:
4941     llvm_unreachable("SPIRV is not yet implemented");
4942     break;
4943   case Triple::XCOFF:
4944     llvm_unreachable("XCOFF is not yet implemented");
4945     break;
4946   case Triple::DXContainer:
4947     llvm_unreachable("DXC is not yet implemented");
4948     break;
4949   }
4950   llvm_unreachable("Unimplemented ObjectFormatType");
4951 }
4952 
4953 void llvm::embedBitcodeInModule(llvm::Module &M, llvm::MemoryBufferRef Buf,
4954                                 bool EmbedBitcode, bool EmbedCmdline,
4955                                 const std::vector<uint8_t> &CmdArgs) {
4956   // Save llvm.compiler.used and remove it.
4957   SmallVector<Constant *, 2> UsedArray;
4958   SmallVector<GlobalValue *, 4> UsedGlobals;
4959   Type *UsedElementType = Type::getInt8Ty(M.getContext())->getPointerTo(0);
4960   GlobalVariable *Used = collectUsedGlobalVariables(M, UsedGlobals, true);
4961   for (auto *GV : UsedGlobals) {
4962     if (GV->getName() != "llvm.embedded.module" &&
4963         GV->getName() != "llvm.cmdline")
4964       UsedArray.push_back(
4965           ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
4966   }
4967   if (Used)
4968     Used->eraseFromParent();
4969 
4970   // Embed the bitcode for the llvm module.
4971   std::string Data;
4972   ArrayRef<uint8_t> ModuleData;
4973   Triple T(M.getTargetTriple());
4974 
4975   if (EmbedBitcode) {
4976     if (Buf.getBufferSize() == 0 ||
4977         !isBitcode((const unsigned char *)Buf.getBufferStart(),
4978                    (const unsigned char *)Buf.getBufferEnd())) {
4979       // If the input is LLVM Assembly, bitcode is produced by serializing
4980       // the module. Use-lists order need to be preserved in this case.
4981       llvm::raw_string_ostream OS(Data);
4982       llvm::WriteBitcodeToFile(M, OS, /* ShouldPreserveUseListOrder */ true);
4983       ModuleData =
4984           ArrayRef<uint8_t>((const uint8_t *)OS.str().data(), OS.str().size());
4985     } else
4986       // If the input is LLVM bitcode, write the input byte stream directly.
4987       ModuleData = ArrayRef<uint8_t>((const uint8_t *)Buf.getBufferStart(),
4988                                      Buf.getBufferSize());
4989   }
4990   llvm::Constant *ModuleConstant =
4991       llvm::ConstantDataArray::get(M.getContext(), ModuleData);
4992   llvm::GlobalVariable *GV = new llvm::GlobalVariable(
4993       M, ModuleConstant->getType(), true, llvm::GlobalValue::PrivateLinkage,
4994       ModuleConstant);
4995   GV->setSection(getSectionNameForBitcode(T));
4996   // Set alignment to 1 to prevent padding between two contributions from input
4997   // sections after linking.
4998   GV->setAlignment(Align(1));
4999   UsedArray.push_back(
5000       ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
5001   if (llvm::GlobalVariable *Old =
5002           M.getGlobalVariable("llvm.embedded.module", true)) {
5003     assert(Old->hasZeroLiveUses() &&
5004            "llvm.embedded.module can only be used once in llvm.compiler.used");
5005     GV->takeName(Old);
5006     Old->eraseFromParent();
5007   } else {
5008     GV->setName("llvm.embedded.module");
5009   }
5010 
5011   // Skip if only bitcode needs to be embedded.
5012   if (EmbedCmdline) {
5013     // Embed command-line options.
5014     ArrayRef<uint8_t> CmdData(const_cast<uint8_t *>(CmdArgs.data()),
5015                               CmdArgs.size());
5016     llvm::Constant *CmdConstant =
5017         llvm::ConstantDataArray::get(M.getContext(), CmdData);
5018     GV = new llvm::GlobalVariable(M, CmdConstant->getType(), true,
5019                                   llvm::GlobalValue::PrivateLinkage,
5020                                   CmdConstant);
5021     GV->setSection(getSectionNameForCommandline(T));
5022     GV->setAlignment(Align(1));
5023     UsedArray.push_back(
5024         ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
5025     if (llvm::GlobalVariable *Old = M.getGlobalVariable("llvm.cmdline", true)) {
5026       assert(Old->hasZeroLiveUses() &&
5027              "llvm.cmdline can only be used once in llvm.compiler.used");
5028       GV->takeName(Old);
5029       Old->eraseFromParent();
5030     } else {
5031       GV->setName("llvm.cmdline");
5032     }
5033   }
5034 
5035   if (UsedArray.empty())
5036     return;
5037 
5038   // Recreate llvm.compiler.used.
5039   ArrayType *ATy = ArrayType::get(UsedElementType, UsedArray.size());
5040   auto *NewUsed = new GlobalVariable(
5041       M, ATy, false, llvm::GlobalValue::AppendingLinkage,
5042       llvm::ConstantArray::get(ATy, UsedArray), "llvm.compiler.used");
5043   NewUsed->setSection("llvm.metadata");
5044 }
5045