xref: /llvm-project/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp (revision c0dac0221dd6fb7ebbd21cdc2ea72022e0152545)
1 //===- Bitcode/Writer/BitcodeWriter.cpp - Bitcode Writer ------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // Bitcode writer implementation.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "llvm/Bitcode/BitcodeWriter.h"
14 #include "ValueEnumerator.h"
15 #include "llvm/ADT/APFloat.h"
16 #include "llvm/ADT/APInt.h"
17 #include "llvm/ADT/ArrayRef.h"
18 #include "llvm/ADT/DenseMap.h"
19 #include "llvm/ADT/None.h"
20 #include "llvm/ADT/Optional.h"
21 #include "llvm/ADT/STLExtras.h"
22 #include "llvm/ADT/SmallString.h"
23 #include "llvm/ADT/SmallVector.h"
24 #include "llvm/ADT/StringMap.h"
25 #include "llvm/ADT/StringRef.h"
26 #include "llvm/ADT/Triple.h"
27 #include "llvm/Bitcode/BitcodeReader.h"
28 #include "llvm/Bitcode/LLVMBitCodes.h"
29 #include "llvm/Bitstream/BitCodes.h"
30 #include "llvm/Bitstream/BitstreamWriter.h"
31 #include "llvm/Config/llvm-config.h"
32 #include "llvm/IR/Attributes.h"
33 #include "llvm/IR/BasicBlock.h"
34 #include "llvm/IR/CallSite.h"
35 #include "llvm/IR/Comdat.h"
36 #include "llvm/IR/Constant.h"
37 #include "llvm/IR/Constants.h"
38 #include "llvm/IR/DebugInfoMetadata.h"
39 #include "llvm/IR/DebugLoc.h"
40 #include "llvm/IR/DerivedTypes.h"
41 #include "llvm/IR/Function.h"
42 #include "llvm/IR/GlobalAlias.h"
43 #include "llvm/IR/GlobalIFunc.h"
44 #include "llvm/IR/GlobalObject.h"
45 #include "llvm/IR/GlobalValue.h"
46 #include "llvm/IR/GlobalVariable.h"
47 #include "llvm/IR/InlineAsm.h"
48 #include "llvm/IR/InstrTypes.h"
49 #include "llvm/IR/Instruction.h"
50 #include "llvm/IR/Instructions.h"
51 #include "llvm/IR/LLVMContext.h"
52 #include "llvm/IR/Metadata.h"
53 #include "llvm/IR/Module.h"
54 #include "llvm/IR/ModuleSummaryIndex.h"
55 #include "llvm/IR/Operator.h"
56 #include "llvm/IR/Type.h"
57 #include "llvm/IR/UseListOrder.h"
58 #include "llvm/IR/Value.h"
59 #include "llvm/IR/ValueSymbolTable.h"
60 #include "llvm/MC/StringTableBuilder.h"
61 #include "llvm/Object/IRSymtab.h"
62 #include "llvm/Support/AtomicOrdering.h"
63 #include "llvm/Support/Casting.h"
64 #include "llvm/Support/CommandLine.h"
65 #include "llvm/Support/Endian.h"
66 #include "llvm/Support/Error.h"
67 #include "llvm/Support/ErrorHandling.h"
68 #include "llvm/Support/MathExtras.h"
69 #include "llvm/Support/SHA1.h"
70 #include "llvm/Support/TargetRegistry.h"
71 #include "llvm/Support/raw_ostream.h"
72 #include <algorithm>
73 #include <cassert>
74 #include <cstddef>
75 #include <cstdint>
76 #include <iterator>
77 #include <map>
78 #include <memory>
79 #include <string>
80 #include <utility>
81 #include <vector>
82 
83 using namespace llvm;
84 
85 static cl::opt<unsigned>
86     IndexThreshold("bitcode-mdindex-threshold", cl::Hidden, cl::init(25),
87                    cl::desc("Number of metadatas above which we emit an index "
88                             "to enable lazy-loading"));
89 
90 static cl::opt<bool> WriteRelBFToSummary(
91     "write-relbf-to-summary", cl::Hidden, cl::init(false),
92     cl::desc("Write relative block frequency to function summary "));
93 
94 extern FunctionSummary::ForceSummaryHotnessType ForceSummaryEdgesCold;
95 
96 namespace {
97 
98 /// These are manifest constants used by the bitcode writer. They do not need to
99 /// be kept in sync with the reader, but need to be consistent within this file.
100 enum {
101   // VALUE_SYMTAB_BLOCK abbrev id's.
102   VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
103   VST_ENTRY_7_ABBREV,
104   VST_ENTRY_6_ABBREV,
105   VST_BBENTRY_6_ABBREV,
106 
107   // CONSTANTS_BLOCK abbrev id's.
108   CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
109   CONSTANTS_INTEGER_ABBREV,
110   CONSTANTS_CE_CAST_Abbrev,
111   CONSTANTS_NULL_Abbrev,
112 
113   // FUNCTION_BLOCK abbrev id's.
114   FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
115   FUNCTION_INST_UNOP_ABBREV,
116   FUNCTION_INST_UNOP_FLAGS_ABBREV,
117   FUNCTION_INST_BINOP_ABBREV,
118   FUNCTION_INST_BINOP_FLAGS_ABBREV,
119   FUNCTION_INST_CAST_ABBREV,
120   FUNCTION_INST_RET_VOID_ABBREV,
121   FUNCTION_INST_RET_VAL_ABBREV,
122   FUNCTION_INST_UNREACHABLE_ABBREV,
123   FUNCTION_INST_GEP_ABBREV,
124 };
125 
126 /// Abstract class to manage the bitcode writing, subclassed for each bitcode
127 /// file type.
128 class BitcodeWriterBase {
129 protected:
130   /// The stream created and owned by the client.
131   BitstreamWriter &Stream;
132 
133   StringTableBuilder &StrtabBuilder;
134 
135 public:
136   /// Constructs a BitcodeWriterBase object that writes to the provided
137   /// \p Stream.
138   BitcodeWriterBase(BitstreamWriter &Stream, StringTableBuilder &StrtabBuilder)
139       : Stream(Stream), StrtabBuilder(StrtabBuilder) {}
140 
141 protected:
142   void writeBitcodeHeader();
143   void writeModuleVersion();
144 };
145 
146 void BitcodeWriterBase::writeModuleVersion() {
147   // VERSION: [version#]
148   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, ArrayRef<uint64_t>{2});
149 }
150 
151 /// Base class to manage the module bitcode writing, currently subclassed for
152 /// ModuleBitcodeWriter and ThinLinkBitcodeWriter.
153 class ModuleBitcodeWriterBase : public BitcodeWriterBase {
154 protected:
155   /// The Module to write to bitcode.
156   const Module &M;
157 
158   /// Enumerates ids for all values in the module.
159   ValueEnumerator VE;
160 
161   /// Optional per-module index to write for ThinLTO.
162   const ModuleSummaryIndex *Index;
163 
164   /// Map that holds the correspondence between GUIDs in the summary index,
165   /// that came from indirect call profiles, and a value id generated by this
166   /// class to use in the VST and summary block records.
167   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
168 
169   /// Tracks the last value id recorded in the GUIDToValueMap.
170   unsigned GlobalValueId;
171 
172   /// Saves the offset of the VSTOffset record that must eventually be
173   /// backpatched with the offset of the actual VST.
174   uint64_t VSTOffsetPlaceholder = 0;
175 
176 public:
177   /// Constructs a ModuleBitcodeWriterBase object for the given Module,
178   /// writing to the provided \p Buffer.
179   ModuleBitcodeWriterBase(const Module &M, StringTableBuilder &StrtabBuilder,
180                           BitstreamWriter &Stream,
181                           bool ShouldPreserveUseListOrder,
182                           const ModuleSummaryIndex *Index)
183       : BitcodeWriterBase(Stream, StrtabBuilder), M(M),
184         VE(M, ShouldPreserveUseListOrder), Index(Index) {
185     // Assign ValueIds to any callee values in the index that came from
186     // indirect call profiles and were recorded as a GUID not a Value*
187     // (which would have been assigned an ID by the ValueEnumerator).
188     // The starting ValueId is just after the number of values in the
189     // ValueEnumerator, so that they can be emitted in the VST.
190     GlobalValueId = VE.getValues().size();
191     if (!Index)
192       return;
193     for (const auto &GUIDSummaryLists : *Index)
194       // Examine all summaries for this GUID.
195       for (auto &Summary : GUIDSummaryLists.second.SummaryList)
196         if (auto FS = dyn_cast<FunctionSummary>(Summary.get()))
197           // For each call in the function summary, see if the call
198           // is to a GUID (which means it is for an indirect call,
199           // otherwise we would have a Value for it). If so, synthesize
200           // a value id.
201           for (auto &CallEdge : FS->calls())
202             if (!CallEdge.first.haveGVs() || !CallEdge.first.getValue())
203               assignValueId(CallEdge.first.getGUID());
204   }
205 
206 protected:
207   void writePerModuleGlobalValueSummary();
208 
209 private:
210   void writePerModuleFunctionSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
211                                            GlobalValueSummary *Summary,
212                                            unsigned ValueID,
213                                            unsigned FSCallsAbbrev,
214                                            unsigned FSCallsProfileAbbrev,
215                                            const Function &F);
216   void writeModuleLevelReferences(const GlobalVariable &V,
217                                   SmallVector<uint64_t, 64> &NameVals,
218                                   unsigned FSModRefsAbbrev,
219                                   unsigned FSModVTableRefsAbbrev);
220 
221   void assignValueId(GlobalValue::GUID ValGUID) {
222     GUIDToValueIdMap[ValGUID] = ++GlobalValueId;
223   }
224 
225   unsigned getValueId(GlobalValue::GUID ValGUID) {
226     const auto &VMI = GUIDToValueIdMap.find(ValGUID);
227     // Expect that any GUID value had a value Id assigned by an
228     // earlier call to assignValueId.
229     assert(VMI != GUIDToValueIdMap.end() &&
230            "GUID does not have assigned value Id");
231     return VMI->second;
232   }
233 
234   // Helper to get the valueId for the type of value recorded in VI.
235   unsigned getValueId(ValueInfo VI) {
236     if (!VI.haveGVs() || !VI.getValue())
237       return getValueId(VI.getGUID());
238     return VE.getValueID(VI.getValue());
239   }
240 
241   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
242 };
243 
244 /// Class to manage the bitcode writing for a module.
245 class ModuleBitcodeWriter : public ModuleBitcodeWriterBase {
246   /// Pointer to the buffer allocated by caller for bitcode writing.
247   const SmallVectorImpl<char> &Buffer;
248 
249   /// True if a module hash record should be written.
250   bool GenerateHash;
251 
252   /// If non-null, when GenerateHash is true, the resulting hash is written
253   /// into ModHash.
254   ModuleHash *ModHash;
255 
256   SHA1 Hasher;
257 
258   /// The start bit of the identification block.
259   uint64_t BitcodeStartBit;
260 
261 public:
262   /// Constructs a ModuleBitcodeWriter object for the given Module,
263   /// writing to the provided \p Buffer.
264   ModuleBitcodeWriter(const Module &M, SmallVectorImpl<char> &Buffer,
265                       StringTableBuilder &StrtabBuilder,
266                       BitstreamWriter &Stream, bool ShouldPreserveUseListOrder,
267                       const ModuleSummaryIndex *Index, bool GenerateHash,
268                       ModuleHash *ModHash = nullptr)
269       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
270                                 ShouldPreserveUseListOrder, Index),
271         Buffer(Buffer), GenerateHash(GenerateHash), ModHash(ModHash),
272         BitcodeStartBit(Stream.GetCurrentBitNo()) {}
273 
274   /// Emit the current module to the bitstream.
275   void write();
276 
277 private:
278   uint64_t bitcodeStartBit() { return BitcodeStartBit; }
279 
280   size_t addToStrtab(StringRef Str);
281 
282   void writeAttributeGroupTable();
283   void writeAttributeTable();
284   void writeTypeTable();
285   void writeComdats();
286   void writeValueSymbolTableForwardDecl();
287   void writeModuleInfo();
288   void writeValueAsMetadata(const ValueAsMetadata *MD,
289                             SmallVectorImpl<uint64_t> &Record);
290   void writeMDTuple(const MDTuple *N, SmallVectorImpl<uint64_t> &Record,
291                     unsigned Abbrev);
292   unsigned createDILocationAbbrev();
293   void writeDILocation(const DILocation *N, SmallVectorImpl<uint64_t> &Record,
294                        unsigned &Abbrev);
295   unsigned createGenericDINodeAbbrev();
296   void writeGenericDINode(const GenericDINode *N,
297                           SmallVectorImpl<uint64_t> &Record, unsigned &Abbrev);
298   void writeDISubrange(const DISubrange *N, SmallVectorImpl<uint64_t> &Record,
299                        unsigned Abbrev);
300   void writeDIEnumerator(const DIEnumerator *N,
301                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
302   void writeDIBasicType(const DIBasicType *N, SmallVectorImpl<uint64_t> &Record,
303                         unsigned Abbrev);
304   void writeDIDerivedType(const DIDerivedType *N,
305                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
306   void writeDICompositeType(const DICompositeType *N,
307                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
308   void writeDISubroutineType(const DISubroutineType *N,
309                              SmallVectorImpl<uint64_t> &Record,
310                              unsigned Abbrev);
311   void writeDIFile(const DIFile *N, SmallVectorImpl<uint64_t> &Record,
312                    unsigned Abbrev);
313   void writeDICompileUnit(const DICompileUnit *N,
314                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
315   void writeDISubprogram(const DISubprogram *N,
316                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
317   void writeDILexicalBlock(const DILexicalBlock *N,
318                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
319   void writeDILexicalBlockFile(const DILexicalBlockFile *N,
320                                SmallVectorImpl<uint64_t> &Record,
321                                unsigned Abbrev);
322   void writeDICommonBlock(const DICommonBlock *N,
323                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
324   void writeDINamespace(const DINamespace *N, SmallVectorImpl<uint64_t> &Record,
325                         unsigned Abbrev);
326   void writeDIMacro(const DIMacro *N, SmallVectorImpl<uint64_t> &Record,
327                     unsigned Abbrev);
328   void writeDIMacroFile(const DIMacroFile *N, SmallVectorImpl<uint64_t> &Record,
329                         unsigned Abbrev);
330   void writeDIModule(const DIModule *N, SmallVectorImpl<uint64_t> &Record,
331                      unsigned Abbrev);
332   void writeDITemplateTypeParameter(const DITemplateTypeParameter *N,
333                                     SmallVectorImpl<uint64_t> &Record,
334                                     unsigned Abbrev);
335   void writeDITemplateValueParameter(const DITemplateValueParameter *N,
336                                      SmallVectorImpl<uint64_t> &Record,
337                                      unsigned Abbrev);
338   void writeDIGlobalVariable(const DIGlobalVariable *N,
339                              SmallVectorImpl<uint64_t> &Record,
340                              unsigned Abbrev);
341   void writeDILocalVariable(const DILocalVariable *N,
342                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
343   void writeDILabel(const DILabel *N,
344                     SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
345   void writeDIExpression(const DIExpression *N,
346                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
347   void writeDIGlobalVariableExpression(const DIGlobalVariableExpression *N,
348                                        SmallVectorImpl<uint64_t> &Record,
349                                        unsigned Abbrev);
350   void writeDIObjCProperty(const DIObjCProperty *N,
351                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
352   void writeDIImportedEntity(const DIImportedEntity *N,
353                              SmallVectorImpl<uint64_t> &Record,
354                              unsigned Abbrev);
355   unsigned createNamedMetadataAbbrev();
356   void writeNamedMetadata(SmallVectorImpl<uint64_t> &Record);
357   unsigned createMetadataStringsAbbrev();
358   void writeMetadataStrings(ArrayRef<const Metadata *> Strings,
359                             SmallVectorImpl<uint64_t> &Record);
360   void writeMetadataRecords(ArrayRef<const Metadata *> MDs,
361                             SmallVectorImpl<uint64_t> &Record,
362                             std::vector<unsigned> *MDAbbrevs = nullptr,
363                             std::vector<uint64_t> *IndexPos = nullptr);
364   void writeModuleMetadata();
365   void writeFunctionMetadata(const Function &F);
366   void writeFunctionMetadataAttachment(const Function &F);
367   void writeGlobalVariableMetadataAttachment(const GlobalVariable &GV);
368   void pushGlobalMetadataAttachment(SmallVectorImpl<uint64_t> &Record,
369                                     const GlobalObject &GO);
370   void writeModuleMetadataKinds();
371   void writeOperandBundleTags();
372   void writeSyncScopeNames();
373   void writeConstants(unsigned FirstVal, unsigned LastVal, bool isGlobal);
374   void writeModuleConstants();
375   bool pushValueAndType(const Value *V, unsigned InstID,
376                         SmallVectorImpl<unsigned> &Vals);
377   void writeOperandBundles(ImmutableCallSite CS, unsigned InstID);
378   void pushValue(const Value *V, unsigned InstID,
379                  SmallVectorImpl<unsigned> &Vals);
380   void pushValueSigned(const Value *V, unsigned InstID,
381                        SmallVectorImpl<uint64_t> &Vals);
382   void writeInstruction(const Instruction &I, unsigned InstID,
383                         SmallVectorImpl<unsigned> &Vals);
384   void writeFunctionLevelValueSymbolTable(const ValueSymbolTable &VST);
385   void writeGlobalValueSymbolTable(
386       DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
387   void writeUseList(UseListOrder &&Order);
388   void writeUseListBlock(const Function *F);
389   void
390   writeFunction(const Function &F,
391                 DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
392   void writeBlockInfo();
393   void writeModuleHash(size_t BlockStartPos);
394 
395   unsigned getEncodedSyncScopeID(SyncScope::ID SSID) {
396     return unsigned(SSID);
397   }
398 };
399 
400 /// Class to manage the bitcode writing for a combined index.
401 class IndexBitcodeWriter : public BitcodeWriterBase {
402   /// The combined index to write to bitcode.
403   const ModuleSummaryIndex &Index;
404 
405   /// When writing a subset of the index for distributed backends, client
406   /// provides a map of modules to the corresponding GUIDs/summaries to write.
407   const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex;
408 
409   /// Map that holds the correspondence between the GUID used in the combined
410   /// index and a value id generated by this class to use in references.
411   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
412 
413   /// Tracks the last value id recorded in the GUIDToValueMap.
414   unsigned GlobalValueId = 0;
415 
416 public:
417   /// Constructs a IndexBitcodeWriter object for the given combined index,
418   /// writing to the provided \p Buffer. When writing a subset of the index
419   /// for a distributed backend, provide a \p ModuleToSummariesForIndex map.
420   IndexBitcodeWriter(BitstreamWriter &Stream, StringTableBuilder &StrtabBuilder,
421                      const ModuleSummaryIndex &Index,
422                      const std::map<std::string, GVSummaryMapTy>
423                          *ModuleToSummariesForIndex = nullptr)
424       : BitcodeWriterBase(Stream, StrtabBuilder), Index(Index),
425         ModuleToSummariesForIndex(ModuleToSummariesForIndex) {
426     // Assign unique value ids to all summaries to be written, for use
427     // in writing out the call graph edges. Save the mapping from GUID
428     // to the new global value id to use when writing those edges, which
429     // are currently saved in the index in terms of GUID.
430     forEachSummary([&](GVInfo I, bool) {
431       GUIDToValueIdMap[I.first] = ++GlobalValueId;
432     });
433   }
434 
435   /// The below iterator returns the GUID and associated summary.
436   using GVInfo = std::pair<GlobalValue::GUID, GlobalValueSummary *>;
437 
438   /// Calls the callback for each value GUID and summary to be written to
439   /// bitcode. This hides the details of whether they are being pulled from the
440   /// entire index or just those in a provided ModuleToSummariesForIndex map.
441   template<typename Functor>
442   void forEachSummary(Functor Callback) {
443     if (ModuleToSummariesForIndex) {
444       for (auto &M : *ModuleToSummariesForIndex)
445         for (auto &Summary : M.second) {
446           Callback(Summary, false);
447           // Ensure aliasee is handled, e.g. for assigning a valueId,
448           // even if we are not importing the aliasee directly (the
449           // imported alias will contain a copy of aliasee).
450           if (auto *AS = dyn_cast<AliasSummary>(Summary.getSecond()))
451             Callback({AS->getAliaseeGUID(), &AS->getAliasee()}, true);
452         }
453     } else {
454       for (auto &Summaries : Index)
455         for (auto &Summary : Summaries.second.SummaryList)
456           Callback({Summaries.first, Summary.get()}, false);
457     }
458   }
459 
460   /// Calls the callback for each entry in the modulePaths StringMap that
461   /// should be written to the module path string table. This hides the details
462   /// of whether they are being pulled from the entire index or just those in a
463   /// provided ModuleToSummariesForIndex map.
464   template <typename Functor> void forEachModule(Functor Callback) {
465     if (ModuleToSummariesForIndex) {
466       for (const auto &M : *ModuleToSummariesForIndex) {
467         const auto &MPI = Index.modulePaths().find(M.first);
468         if (MPI == Index.modulePaths().end()) {
469           // This should only happen if the bitcode file was empty, in which
470           // case we shouldn't be importing (the ModuleToSummariesForIndex
471           // would only include the module we are writing and index for).
472           assert(ModuleToSummariesForIndex->size() == 1);
473           continue;
474         }
475         Callback(*MPI);
476       }
477     } else {
478       for (const auto &MPSE : Index.modulePaths())
479         Callback(MPSE);
480     }
481   }
482 
483   /// Main entry point for writing a combined index to bitcode.
484   void write();
485 
486 private:
487   void writeModStrings();
488   void writeCombinedGlobalValueSummary();
489 
490   Optional<unsigned> getValueId(GlobalValue::GUID ValGUID) {
491     auto VMI = GUIDToValueIdMap.find(ValGUID);
492     if (VMI == GUIDToValueIdMap.end())
493       return None;
494     return VMI->second;
495   }
496 
497   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
498 };
499 
500 } // end anonymous namespace
501 
502 static unsigned getEncodedCastOpcode(unsigned Opcode) {
503   switch (Opcode) {
504   default: llvm_unreachable("Unknown cast instruction!");
505   case Instruction::Trunc   : return bitc::CAST_TRUNC;
506   case Instruction::ZExt    : return bitc::CAST_ZEXT;
507   case Instruction::SExt    : return bitc::CAST_SEXT;
508   case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
509   case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
510   case Instruction::UIToFP  : return bitc::CAST_UITOFP;
511   case Instruction::SIToFP  : return bitc::CAST_SITOFP;
512   case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
513   case Instruction::FPExt   : return bitc::CAST_FPEXT;
514   case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
515   case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
516   case Instruction::BitCast : return bitc::CAST_BITCAST;
517   case Instruction::AddrSpaceCast: return bitc::CAST_ADDRSPACECAST;
518   }
519 }
520 
521 static unsigned getEncodedUnaryOpcode(unsigned Opcode) {
522   switch (Opcode) {
523   default: llvm_unreachable("Unknown binary instruction!");
524   case Instruction::FNeg: return bitc::UNOP_FNEG;
525   }
526 }
527 
528 static unsigned getEncodedBinaryOpcode(unsigned Opcode) {
529   switch (Opcode) {
530   default: llvm_unreachable("Unknown binary instruction!");
531   case Instruction::Add:
532   case Instruction::FAdd: return bitc::BINOP_ADD;
533   case Instruction::Sub:
534   case Instruction::FSub: return bitc::BINOP_SUB;
535   case Instruction::Mul:
536   case Instruction::FMul: return bitc::BINOP_MUL;
537   case Instruction::UDiv: return bitc::BINOP_UDIV;
538   case Instruction::FDiv:
539   case Instruction::SDiv: return bitc::BINOP_SDIV;
540   case Instruction::URem: return bitc::BINOP_UREM;
541   case Instruction::FRem:
542   case Instruction::SRem: return bitc::BINOP_SREM;
543   case Instruction::Shl:  return bitc::BINOP_SHL;
544   case Instruction::LShr: return bitc::BINOP_LSHR;
545   case Instruction::AShr: return bitc::BINOP_ASHR;
546   case Instruction::And:  return bitc::BINOP_AND;
547   case Instruction::Or:   return bitc::BINOP_OR;
548   case Instruction::Xor:  return bitc::BINOP_XOR;
549   }
550 }
551 
552 static unsigned getEncodedRMWOperation(AtomicRMWInst::BinOp Op) {
553   switch (Op) {
554   default: llvm_unreachable("Unknown RMW operation!");
555   case AtomicRMWInst::Xchg: return bitc::RMW_XCHG;
556   case AtomicRMWInst::Add: return bitc::RMW_ADD;
557   case AtomicRMWInst::Sub: return bitc::RMW_SUB;
558   case AtomicRMWInst::And: return bitc::RMW_AND;
559   case AtomicRMWInst::Nand: return bitc::RMW_NAND;
560   case AtomicRMWInst::Or: return bitc::RMW_OR;
561   case AtomicRMWInst::Xor: return bitc::RMW_XOR;
562   case AtomicRMWInst::Max: return bitc::RMW_MAX;
563   case AtomicRMWInst::Min: return bitc::RMW_MIN;
564   case AtomicRMWInst::UMax: return bitc::RMW_UMAX;
565   case AtomicRMWInst::UMin: return bitc::RMW_UMIN;
566   case AtomicRMWInst::FAdd: return bitc::RMW_FADD;
567   case AtomicRMWInst::FSub: return bitc::RMW_FSUB;
568   }
569 }
570 
571 static unsigned getEncodedOrdering(AtomicOrdering Ordering) {
572   switch (Ordering) {
573   case AtomicOrdering::NotAtomic: return bitc::ORDERING_NOTATOMIC;
574   case AtomicOrdering::Unordered: return bitc::ORDERING_UNORDERED;
575   case AtomicOrdering::Monotonic: return bitc::ORDERING_MONOTONIC;
576   case AtomicOrdering::Acquire: return bitc::ORDERING_ACQUIRE;
577   case AtomicOrdering::Release: return bitc::ORDERING_RELEASE;
578   case AtomicOrdering::AcquireRelease: return bitc::ORDERING_ACQREL;
579   case AtomicOrdering::SequentiallyConsistent: return bitc::ORDERING_SEQCST;
580   }
581   llvm_unreachable("Invalid ordering");
582 }
583 
584 static void writeStringRecord(BitstreamWriter &Stream, unsigned Code,
585                               StringRef Str, unsigned AbbrevToUse) {
586   SmallVector<unsigned, 64> Vals;
587 
588   // Code: [strchar x N]
589   for (unsigned i = 0, e = Str.size(); i != e; ++i) {
590     if (AbbrevToUse && !BitCodeAbbrevOp::isChar6(Str[i]))
591       AbbrevToUse = 0;
592     Vals.push_back(Str[i]);
593   }
594 
595   // Emit the finished record.
596   Stream.EmitRecord(Code, Vals, AbbrevToUse);
597 }
598 
599 static uint64_t getAttrKindEncoding(Attribute::AttrKind Kind) {
600   switch (Kind) {
601   case Attribute::Alignment:
602     return bitc::ATTR_KIND_ALIGNMENT;
603   case Attribute::AllocSize:
604     return bitc::ATTR_KIND_ALLOC_SIZE;
605   case Attribute::AlwaysInline:
606     return bitc::ATTR_KIND_ALWAYS_INLINE;
607   case Attribute::ArgMemOnly:
608     return bitc::ATTR_KIND_ARGMEMONLY;
609   case Attribute::Builtin:
610     return bitc::ATTR_KIND_BUILTIN;
611   case Attribute::ByVal:
612     return bitc::ATTR_KIND_BY_VAL;
613   case Attribute::Convergent:
614     return bitc::ATTR_KIND_CONVERGENT;
615   case Attribute::InAlloca:
616     return bitc::ATTR_KIND_IN_ALLOCA;
617   case Attribute::Cold:
618     return bitc::ATTR_KIND_COLD;
619   case Attribute::InaccessibleMemOnly:
620     return bitc::ATTR_KIND_INACCESSIBLEMEM_ONLY;
621   case Attribute::InaccessibleMemOrArgMemOnly:
622     return bitc::ATTR_KIND_INACCESSIBLEMEM_OR_ARGMEMONLY;
623   case Attribute::InlineHint:
624     return bitc::ATTR_KIND_INLINE_HINT;
625   case Attribute::InReg:
626     return bitc::ATTR_KIND_IN_REG;
627   case Attribute::JumpTable:
628     return bitc::ATTR_KIND_JUMP_TABLE;
629   case Attribute::MinSize:
630     return bitc::ATTR_KIND_MIN_SIZE;
631   case Attribute::Naked:
632     return bitc::ATTR_KIND_NAKED;
633   case Attribute::Nest:
634     return bitc::ATTR_KIND_NEST;
635   case Attribute::NoAlias:
636     return bitc::ATTR_KIND_NO_ALIAS;
637   case Attribute::NoBuiltin:
638     return bitc::ATTR_KIND_NO_BUILTIN;
639   case Attribute::NoCapture:
640     return bitc::ATTR_KIND_NO_CAPTURE;
641   case Attribute::NoDuplicate:
642     return bitc::ATTR_KIND_NO_DUPLICATE;
643   case Attribute::NoFree:
644     return bitc::ATTR_KIND_NOFREE;
645   case Attribute::NoImplicitFloat:
646     return bitc::ATTR_KIND_NO_IMPLICIT_FLOAT;
647   case Attribute::NoInline:
648     return bitc::ATTR_KIND_NO_INLINE;
649   case Attribute::NoRecurse:
650     return bitc::ATTR_KIND_NO_RECURSE;
651   case Attribute::NonLazyBind:
652     return bitc::ATTR_KIND_NON_LAZY_BIND;
653   case Attribute::NonNull:
654     return bitc::ATTR_KIND_NON_NULL;
655   case Attribute::Dereferenceable:
656     return bitc::ATTR_KIND_DEREFERENCEABLE;
657   case Attribute::DereferenceableOrNull:
658     return bitc::ATTR_KIND_DEREFERENCEABLE_OR_NULL;
659   case Attribute::NoRedZone:
660     return bitc::ATTR_KIND_NO_RED_ZONE;
661   case Attribute::NoReturn:
662     return bitc::ATTR_KIND_NO_RETURN;
663   case Attribute::NoSync:
664     return bitc::ATTR_KIND_NOSYNC;
665   case Attribute::NoCfCheck:
666     return bitc::ATTR_KIND_NOCF_CHECK;
667   case Attribute::NoUnwind:
668     return bitc::ATTR_KIND_NO_UNWIND;
669   case Attribute::OptForFuzzing:
670     return bitc::ATTR_KIND_OPT_FOR_FUZZING;
671   case Attribute::OptimizeForSize:
672     return bitc::ATTR_KIND_OPTIMIZE_FOR_SIZE;
673   case Attribute::OptimizeNone:
674     return bitc::ATTR_KIND_OPTIMIZE_NONE;
675   case Attribute::ReadNone:
676     return bitc::ATTR_KIND_READ_NONE;
677   case Attribute::ReadOnly:
678     return bitc::ATTR_KIND_READ_ONLY;
679   case Attribute::Returned:
680     return bitc::ATTR_KIND_RETURNED;
681   case Attribute::ReturnsTwice:
682     return bitc::ATTR_KIND_RETURNS_TWICE;
683   case Attribute::SExt:
684     return bitc::ATTR_KIND_S_EXT;
685   case Attribute::Speculatable:
686     return bitc::ATTR_KIND_SPECULATABLE;
687   case Attribute::StackAlignment:
688     return bitc::ATTR_KIND_STACK_ALIGNMENT;
689   case Attribute::StackProtect:
690     return bitc::ATTR_KIND_STACK_PROTECT;
691   case Attribute::StackProtectReq:
692     return bitc::ATTR_KIND_STACK_PROTECT_REQ;
693   case Attribute::StackProtectStrong:
694     return bitc::ATTR_KIND_STACK_PROTECT_STRONG;
695   case Attribute::SafeStack:
696     return bitc::ATTR_KIND_SAFESTACK;
697   case Attribute::ShadowCallStack:
698     return bitc::ATTR_KIND_SHADOWCALLSTACK;
699   case Attribute::StrictFP:
700     return bitc::ATTR_KIND_STRICT_FP;
701   case Attribute::StructRet:
702     return bitc::ATTR_KIND_STRUCT_RET;
703   case Attribute::SanitizeAddress:
704     return bitc::ATTR_KIND_SANITIZE_ADDRESS;
705   case Attribute::SanitizeHWAddress:
706     return bitc::ATTR_KIND_SANITIZE_HWADDRESS;
707   case Attribute::SanitizeThread:
708     return bitc::ATTR_KIND_SANITIZE_THREAD;
709   case Attribute::SanitizeMemory:
710     return bitc::ATTR_KIND_SANITIZE_MEMORY;
711   case Attribute::SpeculativeLoadHardening:
712     return bitc::ATTR_KIND_SPECULATIVE_LOAD_HARDENING;
713   case Attribute::SwiftError:
714     return bitc::ATTR_KIND_SWIFT_ERROR;
715   case Attribute::SwiftSelf:
716     return bitc::ATTR_KIND_SWIFT_SELF;
717   case Attribute::UWTable:
718     return bitc::ATTR_KIND_UW_TABLE;
719   case Attribute::WillReturn:
720     return bitc::ATTR_KIND_WILLRETURN;
721   case Attribute::WriteOnly:
722     return bitc::ATTR_KIND_WRITEONLY;
723   case Attribute::ZExt:
724     return bitc::ATTR_KIND_Z_EXT;
725   case Attribute::ImmArg:
726     return bitc::ATTR_KIND_IMMARG;
727   case Attribute::SanitizeMemTag:
728     return bitc::ATTR_KIND_SANITIZE_MEMTAG;
729   case Attribute::EndAttrKinds:
730     llvm_unreachable("Can not encode end-attribute kinds marker.");
731   case Attribute::None:
732     llvm_unreachable("Can not encode none-attribute.");
733   case Attribute::EmptyKey:
734   case Attribute::TombstoneKey:
735     llvm_unreachable("Trying to encode EmptyKey/TombstoneKey");
736   }
737 
738   llvm_unreachable("Trying to encode unknown attribute");
739 }
740 
741 void ModuleBitcodeWriter::writeAttributeGroupTable() {
742   const std::vector<ValueEnumerator::IndexAndAttrSet> &AttrGrps =
743       VE.getAttributeGroups();
744   if (AttrGrps.empty()) return;
745 
746   Stream.EnterSubblock(bitc::PARAMATTR_GROUP_BLOCK_ID, 3);
747 
748   SmallVector<uint64_t, 64> Record;
749   for (ValueEnumerator::IndexAndAttrSet Pair : AttrGrps) {
750     unsigned AttrListIndex = Pair.first;
751     AttributeSet AS = Pair.second;
752     Record.push_back(VE.getAttributeGroupID(Pair));
753     Record.push_back(AttrListIndex);
754 
755     for (Attribute Attr : AS) {
756       if (Attr.isEnumAttribute()) {
757         Record.push_back(0);
758         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
759       } else if (Attr.isIntAttribute()) {
760         Record.push_back(1);
761         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
762         Record.push_back(Attr.getValueAsInt());
763       } else if (Attr.isStringAttribute()) {
764         StringRef Kind = Attr.getKindAsString();
765         StringRef Val = Attr.getValueAsString();
766 
767         Record.push_back(Val.empty() ? 3 : 4);
768         Record.append(Kind.begin(), Kind.end());
769         Record.push_back(0);
770         if (!Val.empty()) {
771           Record.append(Val.begin(), Val.end());
772           Record.push_back(0);
773         }
774       } else {
775         assert(Attr.isTypeAttribute());
776         Type *Ty = Attr.getValueAsType();
777         Record.push_back(Ty ? 6 : 5);
778         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
779         if (Ty)
780           Record.push_back(VE.getTypeID(Attr.getValueAsType()));
781       }
782     }
783 
784     Stream.EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
785     Record.clear();
786   }
787 
788   Stream.ExitBlock();
789 }
790 
791 void ModuleBitcodeWriter::writeAttributeTable() {
792   const std::vector<AttributeList> &Attrs = VE.getAttributeLists();
793   if (Attrs.empty()) return;
794 
795   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
796 
797   SmallVector<uint64_t, 64> Record;
798   for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
799     AttributeList AL = Attrs[i];
800     for (unsigned i = AL.index_begin(), e = AL.index_end(); i != e; ++i) {
801       AttributeSet AS = AL.getAttributes(i);
802       if (AS.hasAttributes())
803         Record.push_back(VE.getAttributeGroupID({i, AS}));
804     }
805 
806     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
807     Record.clear();
808   }
809 
810   Stream.ExitBlock();
811 }
812 
813 /// WriteTypeTable - Write out the type table for a module.
814 void ModuleBitcodeWriter::writeTypeTable() {
815   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
816 
817   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
818   SmallVector<uint64_t, 64> TypeVals;
819 
820   uint64_t NumBits = VE.computeBitsRequiredForTypeIndicies();
821 
822   // Abbrev for TYPE_CODE_POINTER.
823   auto Abbv = std::make_shared<BitCodeAbbrev>();
824   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
825   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
826   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
827   unsigned PtrAbbrev = Stream.EmitAbbrev(std::move(Abbv));
828 
829   // Abbrev for TYPE_CODE_FUNCTION.
830   Abbv = std::make_shared<BitCodeAbbrev>();
831   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
832   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
833   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
834   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
835   unsigned FunctionAbbrev = Stream.EmitAbbrev(std::move(Abbv));
836 
837   // Abbrev for TYPE_CODE_STRUCT_ANON.
838   Abbv = std::make_shared<BitCodeAbbrev>();
839   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
840   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
841   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
842   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
843   unsigned StructAnonAbbrev = Stream.EmitAbbrev(std::move(Abbv));
844 
845   // Abbrev for TYPE_CODE_STRUCT_NAME.
846   Abbv = std::make_shared<BitCodeAbbrev>();
847   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
848   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
849   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
850   unsigned StructNameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
851 
852   // Abbrev for TYPE_CODE_STRUCT_NAMED.
853   Abbv = std::make_shared<BitCodeAbbrev>();
854   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
855   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
856   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
857   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
858   unsigned StructNamedAbbrev = Stream.EmitAbbrev(std::move(Abbv));
859 
860   // Abbrev for TYPE_CODE_ARRAY.
861   Abbv = std::make_shared<BitCodeAbbrev>();
862   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
863   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
864   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
865   unsigned ArrayAbbrev = Stream.EmitAbbrev(std::move(Abbv));
866 
867   // Emit an entry count so the reader can reserve space.
868   TypeVals.push_back(TypeList.size());
869   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
870   TypeVals.clear();
871 
872   // Loop over all of the types, emitting each in turn.
873   for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
874     Type *T = TypeList[i];
875     int AbbrevToUse = 0;
876     unsigned Code = 0;
877 
878     switch (T->getTypeID()) {
879     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;      break;
880     case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;      break;
881     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;     break;
882     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE;    break;
883     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80;  break;
884     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128;     break;
885     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
886     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;     break;
887     case Type::MetadataTyID:  Code = bitc::TYPE_CODE_METADATA;  break;
888     case Type::X86_MMXTyID:   Code = bitc::TYPE_CODE_X86_MMX;   break;
889     case Type::TokenTyID:     Code = bitc::TYPE_CODE_TOKEN;     break;
890     case Type::IntegerTyID:
891       // INTEGER: [width]
892       Code = bitc::TYPE_CODE_INTEGER;
893       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
894       break;
895     case Type::PointerTyID: {
896       PointerType *PTy = cast<PointerType>(T);
897       // POINTER: [pointee type, address space]
898       Code = bitc::TYPE_CODE_POINTER;
899       TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
900       unsigned AddressSpace = PTy->getAddressSpace();
901       TypeVals.push_back(AddressSpace);
902       if (AddressSpace == 0) AbbrevToUse = PtrAbbrev;
903       break;
904     }
905     case Type::FunctionTyID: {
906       FunctionType *FT = cast<FunctionType>(T);
907       // FUNCTION: [isvararg, retty, paramty x N]
908       Code = bitc::TYPE_CODE_FUNCTION;
909       TypeVals.push_back(FT->isVarArg());
910       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
911       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
912         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
913       AbbrevToUse = FunctionAbbrev;
914       break;
915     }
916     case Type::StructTyID: {
917       StructType *ST = cast<StructType>(T);
918       // STRUCT: [ispacked, eltty x N]
919       TypeVals.push_back(ST->isPacked());
920       // Output all of the element types.
921       for (StructType::element_iterator I = ST->element_begin(),
922            E = ST->element_end(); I != E; ++I)
923         TypeVals.push_back(VE.getTypeID(*I));
924 
925       if (ST->isLiteral()) {
926         Code = bitc::TYPE_CODE_STRUCT_ANON;
927         AbbrevToUse = StructAnonAbbrev;
928       } else {
929         if (ST->isOpaque()) {
930           Code = bitc::TYPE_CODE_OPAQUE;
931         } else {
932           Code = bitc::TYPE_CODE_STRUCT_NAMED;
933           AbbrevToUse = StructNamedAbbrev;
934         }
935 
936         // Emit the name if it is present.
937         if (!ST->getName().empty())
938           writeStringRecord(Stream, bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
939                             StructNameAbbrev);
940       }
941       break;
942     }
943     case Type::ArrayTyID: {
944       ArrayType *AT = cast<ArrayType>(T);
945       // ARRAY: [numelts, eltty]
946       Code = bitc::TYPE_CODE_ARRAY;
947       TypeVals.push_back(AT->getNumElements());
948       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
949       AbbrevToUse = ArrayAbbrev;
950       break;
951     }
952     case Type::VectorTyID: {
953       VectorType *VT = cast<VectorType>(T);
954       // VECTOR [numelts, eltty] or
955       //        [numelts, eltty, scalable]
956       Code = bitc::TYPE_CODE_VECTOR;
957       TypeVals.push_back(VT->getNumElements());
958       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
959       if (VT->isScalable())
960         TypeVals.push_back(VT->isScalable());
961       break;
962     }
963     }
964 
965     // Emit the finished record.
966     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
967     TypeVals.clear();
968   }
969 
970   Stream.ExitBlock();
971 }
972 
973 static unsigned getEncodedLinkage(const GlobalValue::LinkageTypes Linkage) {
974   switch (Linkage) {
975   case GlobalValue::ExternalLinkage:
976     return 0;
977   case GlobalValue::WeakAnyLinkage:
978     return 16;
979   case GlobalValue::AppendingLinkage:
980     return 2;
981   case GlobalValue::InternalLinkage:
982     return 3;
983   case GlobalValue::LinkOnceAnyLinkage:
984     return 18;
985   case GlobalValue::ExternalWeakLinkage:
986     return 7;
987   case GlobalValue::CommonLinkage:
988     return 8;
989   case GlobalValue::PrivateLinkage:
990     return 9;
991   case GlobalValue::WeakODRLinkage:
992     return 17;
993   case GlobalValue::LinkOnceODRLinkage:
994     return 19;
995   case GlobalValue::AvailableExternallyLinkage:
996     return 12;
997   }
998   llvm_unreachable("Invalid linkage");
999 }
1000 
1001 static unsigned getEncodedLinkage(const GlobalValue &GV) {
1002   return getEncodedLinkage(GV.getLinkage());
1003 }
1004 
1005 static uint64_t getEncodedFFlags(FunctionSummary::FFlags Flags) {
1006   uint64_t RawFlags = 0;
1007   RawFlags |= Flags.ReadNone;
1008   RawFlags |= (Flags.ReadOnly << 1);
1009   RawFlags |= (Flags.NoRecurse << 2);
1010   RawFlags |= (Flags.ReturnDoesNotAlias << 3);
1011   RawFlags |= (Flags.NoInline << 4);
1012   RawFlags |= (Flags.AlwaysInline << 5);
1013   return RawFlags;
1014 }
1015 
1016 // Decode the flags for GlobalValue in the summary
1017 static uint64_t getEncodedGVSummaryFlags(GlobalValueSummary::GVFlags Flags) {
1018   uint64_t RawFlags = 0;
1019 
1020   RawFlags |= Flags.NotEligibleToImport; // bool
1021   RawFlags |= (Flags.Live << 1);
1022   RawFlags |= (Flags.DSOLocal << 2);
1023   RawFlags |= (Flags.CanAutoHide << 3);
1024 
1025   // Linkage don't need to be remapped at that time for the summary. Any future
1026   // change to the getEncodedLinkage() function will need to be taken into
1027   // account here as well.
1028   RawFlags = (RawFlags << 4) | Flags.Linkage; // 4 bits
1029 
1030   return RawFlags;
1031 }
1032 
1033 static uint64_t getEncodedGVarFlags(GlobalVarSummary::GVarFlags Flags) {
1034   uint64_t RawFlags = Flags.MaybeReadOnly | (Flags.MaybeWriteOnly << 1) |
1035                       (Flags.Constant << 2) | Flags.VCallVisibility << 3;
1036   return RawFlags;
1037 }
1038 
1039 static unsigned getEncodedVisibility(const GlobalValue &GV) {
1040   switch (GV.getVisibility()) {
1041   case GlobalValue::DefaultVisibility:   return 0;
1042   case GlobalValue::HiddenVisibility:    return 1;
1043   case GlobalValue::ProtectedVisibility: return 2;
1044   }
1045   llvm_unreachable("Invalid visibility");
1046 }
1047 
1048 static unsigned getEncodedDLLStorageClass(const GlobalValue &GV) {
1049   switch (GV.getDLLStorageClass()) {
1050   case GlobalValue::DefaultStorageClass:   return 0;
1051   case GlobalValue::DLLImportStorageClass: return 1;
1052   case GlobalValue::DLLExportStorageClass: return 2;
1053   }
1054   llvm_unreachable("Invalid DLL storage class");
1055 }
1056 
1057 static unsigned getEncodedThreadLocalMode(const GlobalValue &GV) {
1058   switch (GV.getThreadLocalMode()) {
1059     case GlobalVariable::NotThreadLocal:         return 0;
1060     case GlobalVariable::GeneralDynamicTLSModel: return 1;
1061     case GlobalVariable::LocalDynamicTLSModel:   return 2;
1062     case GlobalVariable::InitialExecTLSModel:    return 3;
1063     case GlobalVariable::LocalExecTLSModel:      return 4;
1064   }
1065   llvm_unreachable("Invalid TLS model");
1066 }
1067 
1068 static unsigned getEncodedComdatSelectionKind(const Comdat &C) {
1069   switch (C.getSelectionKind()) {
1070   case Comdat::Any:
1071     return bitc::COMDAT_SELECTION_KIND_ANY;
1072   case Comdat::ExactMatch:
1073     return bitc::COMDAT_SELECTION_KIND_EXACT_MATCH;
1074   case Comdat::Largest:
1075     return bitc::COMDAT_SELECTION_KIND_LARGEST;
1076   case Comdat::NoDuplicates:
1077     return bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES;
1078   case Comdat::SameSize:
1079     return bitc::COMDAT_SELECTION_KIND_SAME_SIZE;
1080   }
1081   llvm_unreachable("Invalid selection kind");
1082 }
1083 
1084 static unsigned getEncodedUnnamedAddr(const GlobalValue &GV) {
1085   switch (GV.getUnnamedAddr()) {
1086   case GlobalValue::UnnamedAddr::None:   return 0;
1087   case GlobalValue::UnnamedAddr::Local:  return 2;
1088   case GlobalValue::UnnamedAddr::Global: return 1;
1089   }
1090   llvm_unreachable("Invalid unnamed_addr");
1091 }
1092 
1093 size_t ModuleBitcodeWriter::addToStrtab(StringRef Str) {
1094   if (GenerateHash)
1095     Hasher.update(Str);
1096   return StrtabBuilder.add(Str);
1097 }
1098 
1099 void ModuleBitcodeWriter::writeComdats() {
1100   SmallVector<unsigned, 64> Vals;
1101   for (const Comdat *C : VE.getComdats()) {
1102     // COMDAT: [strtab offset, strtab size, selection_kind]
1103     Vals.push_back(addToStrtab(C->getName()));
1104     Vals.push_back(C->getName().size());
1105     Vals.push_back(getEncodedComdatSelectionKind(*C));
1106     Stream.EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
1107     Vals.clear();
1108   }
1109 }
1110 
1111 /// Write a record that will eventually hold the word offset of the
1112 /// module-level VST. For now the offset is 0, which will be backpatched
1113 /// after the real VST is written. Saves the bit offset to backpatch.
1114 void ModuleBitcodeWriter::writeValueSymbolTableForwardDecl() {
1115   // Write a placeholder value in for the offset of the real VST,
1116   // which is written after the function blocks so that it can include
1117   // the offset of each function. The placeholder offset will be
1118   // updated when the real VST is written.
1119   auto Abbv = std::make_shared<BitCodeAbbrev>();
1120   Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_VSTOFFSET));
1121   // Blocks are 32-bit aligned, so we can use a 32-bit word offset to
1122   // hold the real VST offset. Must use fixed instead of VBR as we don't
1123   // know how many VBR chunks to reserve ahead of time.
1124   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
1125   unsigned VSTOffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1126 
1127   // Emit the placeholder
1128   uint64_t Vals[] = {bitc::MODULE_CODE_VSTOFFSET, 0};
1129   Stream.EmitRecordWithAbbrev(VSTOffsetAbbrev, Vals);
1130 
1131   // Compute and save the bit offset to the placeholder, which will be
1132   // patched when the real VST is written. We can simply subtract the 32-bit
1133   // fixed size from the current bit number to get the location to backpatch.
1134   VSTOffsetPlaceholder = Stream.GetCurrentBitNo() - 32;
1135 }
1136 
1137 enum StringEncoding { SE_Char6, SE_Fixed7, SE_Fixed8 };
1138 
1139 /// Determine the encoding to use for the given string name and length.
1140 static StringEncoding getStringEncoding(StringRef Str) {
1141   bool isChar6 = true;
1142   for (char C : Str) {
1143     if (isChar6)
1144       isChar6 = BitCodeAbbrevOp::isChar6(C);
1145     if ((unsigned char)C & 128)
1146       // don't bother scanning the rest.
1147       return SE_Fixed8;
1148   }
1149   if (isChar6)
1150     return SE_Char6;
1151   return SE_Fixed7;
1152 }
1153 
1154 /// Emit top-level description of module, including target triple, inline asm,
1155 /// descriptors for global variables, and function prototype info.
1156 /// Returns the bit offset to backpatch with the location of the real VST.
1157 void ModuleBitcodeWriter::writeModuleInfo() {
1158   // Emit various pieces of data attached to a module.
1159   if (!M.getTargetTriple().empty())
1160     writeStringRecord(Stream, bitc::MODULE_CODE_TRIPLE, M.getTargetTriple(),
1161                       0 /*TODO*/);
1162   const std::string &DL = M.getDataLayoutStr();
1163   if (!DL.empty())
1164     writeStringRecord(Stream, bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/);
1165   if (!M.getModuleInlineAsm().empty())
1166     writeStringRecord(Stream, bitc::MODULE_CODE_ASM, M.getModuleInlineAsm(),
1167                       0 /*TODO*/);
1168 
1169   // Emit information about sections and GC, computing how many there are. Also
1170   // compute the maximum alignment value.
1171   std::map<std::string, unsigned> SectionMap;
1172   std::map<std::string, unsigned> GCMap;
1173   unsigned MaxAlignment = 0;
1174   unsigned MaxGlobalType = 0;
1175   for (const GlobalValue &GV : M.globals()) {
1176     MaxAlignment = std::max(MaxAlignment, GV.getAlignment());
1177     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getValueType()));
1178     if (GV.hasSection()) {
1179       // Give section names unique ID's.
1180       unsigned &Entry = SectionMap[std::string(GV.getSection())];
1181       if (!Entry) {
1182         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
1183                           0 /*TODO*/);
1184         Entry = SectionMap.size();
1185       }
1186     }
1187   }
1188   for (const Function &F : M) {
1189     MaxAlignment = std::max(MaxAlignment, F.getAlignment());
1190     if (F.hasSection()) {
1191       // Give section names unique ID's.
1192       unsigned &Entry = SectionMap[std::string(F.getSection())];
1193       if (!Entry) {
1194         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
1195                           0 /*TODO*/);
1196         Entry = SectionMap.size();
1197       }
1198     }
1199     if (F.hasGC()) {
1200       // Same for GC names.
1201       unsigned &Entry = GCMap[F.getGC()];
1202       if (!Entry) {
1203         writeStringRecord(Stream, bitc::MODULE_CODE_GCNAME, F.getGC(),
1204                           0 /*TODO*/);
1205         Entry = GCMap.size();
1206       }
1207     }
1208   }
1209 
1210   // Emit abbrev for globals, now that we know # sections and max alignment.
1211   unsigned SimpleGVarAbbrev = 0;
1212   if (!M.global_empty()) {
1213     // Add an abbrev for common globals with no visibility or thread localness.
1214     auto Abbv = std::make_shared<BitCodeAbbrev>();
1215     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
1216     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1217     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1218     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1219                               Log2_32_Ceil(MaxGlobalType+1)));
1220     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddrSpace << 2
1221                                                            //| explicitType << 1
1222                                                            //| constant
1223     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Initializer.
1224     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // Linkage.
1225     if (MaxAlignment == 0)                                 // Alignment.
1226       Abbv->Add(BitCodeAbbrevOp(0));
1227     else {
1228       unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
1229       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1230                                Log2_32_Ceil(MaxEncAlignment+1)));
1231     }
1232     if (SectionMap.empty())                                    // Section.
1233       Abbv->Add(BitCodeAbbrevOp(0));
1234     else
1235       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1236                                Log2_32_Ceil(SectionMap.size()+1)));
1237     // Don't bother emitting vis + thread local.
1238     SimpleGVarAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1239   }
1240 
1241   SmallVector<unsigned, 64> Vals;
1242   // Emit the module's source file name.
1243   {
1244     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
1245     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
1246     if (Bits == SE_Char6)
1247       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
1248     else if (Bits == SE_Fixed7)
1249       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
1250 
1251     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
1252     auto Abbv = std::make_shared<BitCodeAbbrev>();
1253     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
1254     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1255     Abbv->Add(AbbrevOpToUse);
1256     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1257 
1258     for (const auto P : M.getSourceFileName())
1259       Vals.push_back((unsigned char)P);
1260 
1261     // Emit the finished record.
1262     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
1263     Vals.clear();
1264   }
1265 
1266   // Emit the global variable information.
1267   for (const GlobalVariable &GV : M.globals()) {
1268     unsigned AbbrevToUse = 0;
1269 
1270     // GLOBALVAR: [strtab offset, strtab size, type, isconst, initid,
1271     //             linkage, alignment, section, visibility, threadlocal,
1272     //             unnamed_addr, externally_initialized, dllstorageclass,
1273     //             comdat, attributes, DSO_Local]
1274     Vals.push_back(addToStrtab(GV.getName()));
1275     Vals.push_back(GV.getName().size());
1276     Vals.push_back(VE.getTypeID(GV.getValueType()));
1277     Vals.push_back(GV.getType()->getAddressSpace() << 2 | 2 | GV.isConstant());
1278     Vals.push_back(GV.isDeclaration() ? 0 :
1279                    (VE.getValueID(GV.getInitializer()) + 1));
1280     Vals.push_back(getEncodedLinkage(GV));
1281     Vals.push_back(Log2_32(GV.getAlignment())+1);
1282     Vals.push_back(GV.hasSection() ? SectionMap[std::string(GV.getSection())]
1283                                    : 0);
1284     if (GV.isThreadLocal() ||
1285         GV.getVisibility() != GlobalValue::DefaultVisibility ||
1286         GV.getUnnamedAddr() != GlobalValue::UnnamedAddr::None ||
1287         GV.isExternallyInitialized() ||
1288         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
1289         GV.hasComdat() ||
1290         GV.hasAttributes() ||
1291         GV.isDSOLocal() ||
1292         GV.hasPartition()) {
1293       Vals.push_back(getEncodedVisibility(GV));
1294       Vals.push_back(getEncodedThreadLocalMode(GV));
1295       Vals.push_back(getEncodedUnnamedAddr(GV));
1296       Vals.push_back(GV.isExternallyInitialized());
1297       Vals.push_back(getEncodedDLLStorageClass(GV));
1298       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
1299 
1300       auto AL = GV.getAttributesAsList(AttributeList::FunctionIndex);
1301       Vals.push_back(VE.getAttributeListID(AL));
1302 
1303       Vals.push_back(GV.isDSOLocal());
1304       Vals.push_back(addToStrtab(GV.getPartition()));
1305       Vals.push_back(GV.getPartition().size());
1306     } else {
1307       AbbrevToUse = SimpleGVarAbbrev;
1308     }
1309 
1310     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
1311     Vals.clear();
1312   }
1313 
1314   // Emit the function proto information.
1315   for (const Function &F : M) {
1316     // FUNCTION:  [strtab offset, strtab size, type, callingconv, isproto,
1317     //             linkage, paramattrs, alignment, section, visibility, gc,
1318     //             unnamed_addr, prologuedata, dllstorageclass, comdat,
1319     //             prefixdata, personalityfn, DSO_Local, addrspace]
1320     Vals.push_back(addToStrtab(F.getName()));
1321     Vals.push_back(F.getName().size());
1322     Vals.push_back(VE.getTypeID(F.getFunctionType()));
1323     Vals.push_back(F.getCallingConv());
1324     Vals.push_back(F.isDeclaration());
1325     Vals.push_back(getEncodedLinkage(F));
1326     Vals.push_back(VE.getAttributeListID(F.getAttributes()));
1327     Vals.push_back(Log2_32(F.getAlignment())+1);
1328     Vals.push_back(F.hasSection() ? SectionMap[std::string(F.getSection())]
1329                                   : 0);
1330     Vals.push_back(getEncodedVisibility(F));
1331     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
1332     Vals.push_back(getEncodedUnnamedAddr(F));
1333     Vals.push_back(F.hasPrologueData() ? (VE.getValueID(F.getPrologueData()) + 1)
1334                                        : 0);
1335     Vals.push_back(getEncodedDLLStorageClass(F));
1336     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
1337     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
1338                                      : 0);
1339     Vals.push_back(
1340         F.hasPersonalityFn() ? (VE.getValueID(F.getPersonalityFn()) + 1) : 0);
1341 
1342     Vals.push_back(F.isDSOLocal());
1343     Vals.push_back(F.getAddressSpace());
1344     Vals.push_back(addToStrtab(F.getPartition()));
1345     Vals.push_back(F.getPartition().size());
1346 
1347     unsigned AbbrevToUse = 0;
1348     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
1349     Vals.clear();
1350   }
1351 
1352   // Emit the alias information.
1353   for (const GlobalAlias &A : M.aliases()) {
1354     // ALIAS: [strtab offset, strtab size, alias type, aliasee val#, linkage,
1355     //         visibility, dllstorageclass, threadlocal, unnamed_addr,
1356     //         DSO_Local]
1357     Vals.push_back(addToStrtab(A.getName()));
1358     Vals.push_back(A.getName().size());
1359     Vals.push_back(VE.getTypeID(A.getValueType()));
1360     Vals.push_back(A.getType()->getAddressSpace());
1361     Vals.push_back(VE.getValueID(A.getAliasee()));
1362     Vals.push_back(getEncodedLinkage(A));
1363     Vals.push_back(getEncodedVisibility(A));
1364     Vals.push_back(getEncodedDLLStorageClass(A));
1365     Vals.push_back(getEncodedThreadLocalMode(A));
1366     Vals.push_back(getEncodedUnnamedAddr(A));
1367     Vals.push_back(A.isDSOLocal());
1368     Vals.push_back(addToStrtab(A.getPartition()));
1369     Vals.push_back(A.getPartition().size());
1370 
1371     unsigned AbbrevToUse = 0;
1372     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
1373     Vals.clear();
1374   }
1375 
1376   // Emit the ifunc information.
1377   for (const GlobalIFunc &I : M.ifuncs()) {
1378     // IFUNC: [strtab offset, strtab size, ifunc type, address space, resolver
1379     //         val#, linkage, visibility, DSO_Local]
1380     Vals.push_back(addToStrtab(I.getName()));
1381     Vals.push_back(I.getName().size());
1382     Vals.push_back(VE.getTypeID(I.getValueType()));
1383     Vals.push_back(I.getType()->getAddressSpace());
1384     Vals.push_back(VE.getValueID(I.getResolver()));
1385     Vals.push_back(getEncodedLinkage(I));
1386     Vals.push_back(getEncodedVisibility(I));
1387     Vals.push_back(I.isDSOLocal());
1388     Vals.push_back(addToStrtab(I.getPartition()));
1389     Vals.push_back(I.getPartition().size());
1390     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
1391     Vals.clear();
1392   }
1393 
1394   writeValueSymbolTableForwardDecl();
1395 }
1396 
1397 static uint64_t getOptimizationFlags(const Value *V) {
1398   uint64_t Flags = 0;
1399 
1400   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
1401     if (OBO->hasNoSignedWrap())
1402       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
1403     if (OBO->hasNoUnsignedWrap())
1404       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
1405   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
1406     if (PEO->isExact())
1407       Flags |= 1 << bitc::PEO_EXACT;
1408   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
1409     if (FPMO->hasAllowReassoc())
1410       Flags |= bitc::AllowReassoc;
1411     if (FPMO->hasNoNaNs())
1412       Flags |= bitc::NoNaNs;
1413     if (FPMO->hasNoInfs())
1414       Flags |= bitc::NoInfs;
1415     if (FPMO->hasNoSignedZeros())
1416       Flags |= bitc::NoSignedZeros;
1417     if (FPMO->hasAllowReciprocal())
1418       Flags |= bitc::AllowReciprocal;
1419     if (FPMO->hasAllowContract())
1420       Flags |= bitc::AllowContract;
1421     if (FPMO->hasApproxFunc())
1422       Flags |= bitc::ApproxFunc;
1423   }
1424 
1425   return Flags;
1426 }
1427 
1428 void ModuleBitcodeWriter::writeValueAsMetadata(
1429     const ValueAsMetadata *MD, SmallVectorImpl<uint64_t> &Record) {
1430   // Mimic an MDNode with a value as one operand.
1431   Value *V = MD->getValue();
1432   Record.push_back(VE.getTypeID(V->getType()));
1433   Record.push_back(VE.getValueID(V));
1434   Stream.EmitRecord(bitc::METADATA_VALUE, Record, 0);
1435   Record.clear();
1436 }
1437 
1438 void ModuleBitcodeWriter::writeMDTuple(const MDTuple *N,
1439                                        SmallVectorImpl<uint64_t> &Record,
1440                                        unsigned Abbrev) {
1441   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
1442     Metadata *MD = N->getOperand(i);
1443     assert(!(MD && isa<LocalAsMetadata>(MD)) &&
1444            "Unexpected function-local metadata");
1445     Record.push_back(VE.getMetadataOrNullID(MD));
1446   }
1447   Stream.EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
1448                                     : bitc::METADATA_NODE,
1449                     Record, Abbrev);
1450   Record.clear();
1451 }
1452 
1453 unsigned ModuleBitcodeWriter::createDILocationAbbrev() {
1454   // Assume the column is usually under 128, and always output the inlined-at
1455   // location (it's never more expensive than building an array size 1).
1456   auto Abbv = std::make_shared<BitCodeAbbrev>();
1457   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
1458   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1459   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1460   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1461   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1462   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1463   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1464   return Stream.EmitAbbrev(std::move(Abbv));
1465 }
1466 
1467 void ModuleBitcodeWriter::writeDILocation(const DILocation *N,
1468                                           SmallVectorImpl<uint64_t> &Record,
1469                                           unsigned &Abbrev) {
1470   if (!Abbrev)
1471     Abbrev = createDILocationAbbrev();
1472 
1473   Record.push_back(N->isDistinct());
1474   Record.push_back(N->getLine());
1475   Record.push_back(N->getColumn());
1476   Record.push_back(VE.getMetadataID(N->getScope()));
1477   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
1478   Record.push_back(N->isImplicitCode());
1479 
1480   Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
1481   Record.clear();
1482 }
1483 
1484 unsigned ModuleBitcodeWriter::createGenericDINodeAbbrev() {
1485   // Assume the column is usually under 128, and always output the inlined-at
1486   // location (it's never more expensive than building an array size 1).
1487   auto Abbv = std::make_shared<BitCodeAbbrev>();
1488   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
1489   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1490   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1491   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1492   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1493   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1494   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1495   return Stream.EmitAbbrev(std::move(Abbv));
1496 }
1497 
1498 void ModuleBitcodeWriter::writeGenericDINode(const GenericDINode *N,
1499                                              SmallVectorImpl<uint64_t> &Record,
1500                                              unsigned &Abbrev) {
1501   if (!Abbrev)
1502     Abbrev = createGenericDINodeAbbrev();
1503 
1504   Record.push_back(N->isDistinct());
1505   Record.push_back(N->getTag());
1506   Record.push_back(0); // Per-tag version field; unused for now.
1507 
1508   for (auto &I : N->operands())
1509     Record.push_back(VE.getMetadataOrNullID(I));
1510 
1511   Stream.EmitRecord(bitc::METADATA_GENERIC_DEBUG, Record, Abbrev);
1512   Record.clear();
1513 }
1514 
1515 static uint64_t rotateSign(int64_t I) {
1516   uint64_t U = I;
1517   return I < 0 ? ~(U << 1) : U << 1;
1518 }
1519 
1520 void ModuleBitcodeWriter::writeDISubrange(const DISubrange *N,
1521                                           SmallVectorImpl<uint64_t> &Record,
1522                                           unsigned Abbrev) {
1523   const uint64_t Version = 1 << 1;
1524   Record.push_back((uint64_t)N->isDistinct() | Version);
1525   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1526   Record.push_back(rotateSign(N->getLowerBound()));
1527 
1528   Stream.EmitRecord(bitc::METADATA_SUBRANGE, Record, Abbrev);
1529   Record.clear();
1530 }
1531 
1532 void ModuleBitcodeWriter::writeDIEnumerator(const DIEnumerator *N,
1533                                             SmallVectorImpl<uint64_t> &Record,
1534                                             unsigned Abbrev) {
1535   Record.push_back((N->isUnsigned() << 1) | N->isDistinct());
1536   Record.push_back(rotateSign(N->getValue()));
1537   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1538 
1539   Stream.EmitRecord(bitc::METADATA_ENUMERATOR, Record, Abbrev);
1540   Record.clear();
1541 }
1542 
1543 void ModuleBitcodeWriter::writeDIBasicType(const DIBasicType *N,
1544                                            SmallVectorImpl<uint64_t> &Record,
1545                                            unsigned Abbrev) {
1546   Record.push_back(N->isDistinct());
1547   Record.push_back(N->getTag());
1548   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1549   Record.push_back(N->getSizeInBits());
1550   Record.push_back(N->getAlignInBits());
1551   Record.push_back(N->getEncoding());
1552   Record.push_back(N->getFlags());
1553 
1554   Stream.EmitRecord(bitc::METADATA_BASIC_TYPE, Record, Abbrev);
1555   Record.clear();
1556 }
1557 
1558 void ModuleBitcodeWriter::writeDIDerivedType(const DIDerivedType *N,
1559                                              SmallVectorImpl<uint64_t> &Record,
1560                                              unsigned Abbrev) {
1561   Record.push_back(N->isDistinct());
1562   Record.push_back(N->getTag());
1563   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1564   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1565   Record.push_back(N->getLine());
1566   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1567   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1568   Record.push_back(N->getSizeInBits());
1569   Record.push_back(N->getAlignInBits());
1570   Record.push_back(N->getOffsetInBits());
1571   Record.push_back(N->getFlags());
1572   Record.push_back(VE.getMetadataOrNullID(N->getExtraData()));
1573 
1574   // DWARF address space is encoded as N->getDWARFAddressSpace() + 1. 0 means
1575   // that there is no DWARF address space associated with DIDerivedType.
1576   if (const auto &DWARFAddressSpace = N->getDWARFAddressSpace())
1577     Record.push_back(*DWARFAddressSpace + 1);
1578   else
1579     Record.push_back(0);
1580 
1581   Stream.EmitRecord(bitc::METADATA_DERIVED_TYPE, Record, Abbrev);
1582   Record.clear();
1583 }
1584 
1585 void ModuleBitcodeWriter::writeDICompositeType(
1586     const DICompositeType *N, SmallVectorImpl<uint64_t> &Record,
1587     unsigned Abbrev) {
1588   const unsigned IsNotUsedInOldTypeRef = 0x2;
1589   Record.push_back(IsNotUsedInOldTypeRef | (unsigned)N->isDistinct());
1590   Record.push_back(N->getTag());
1591   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1592   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1593   Record.push_back(N->getLine());
1594   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1595   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1596   Record.push_back(N->getSizeInBits());
1597   Record.push_back(N->getAlignInBits());
1598   Record.push_back(N->getOffsetInBits());
1599   Record.push_back(N->getFlags());
1600   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1601   Record.push_back(N->getRuntimeLang());
1602   Record.push_back(VE.getMetadataOrNullID(N->getVTableHolder()));
1603   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1604   Record.push_back(VE.getMetadataOrNullID(N->getRawIdentifier()));
1605   Record.push_back(VE.getMetadataOrNullID(N->getDiscriminator()));
1606 
1607   Stream.EmitRecord(bitc::METADATA_COMPOSITE_TYPE, Record, Abbrev);
1608   Record.clear();
1609 }
1610 
1611 void ModuleBitcodeWriter::writeDISubroutineType(
1612     const DISubroutineType *N, SmallVectorImpl<uint64_t> &Record,
1613     unsigned Abbrev) {
1614   const unsigned HasNoOldTypeRefs = 0x2;
1615   Record.push_back(HasNoOldTypeRefs | (unsigned)N->isDistinct());
1616   Record.push_back(N->getFlags());
1617   Record.push_back(VE.getMetadataOrNullID(N->getTypeArray().get()));
1618   Record.push_back(N->getCC());
1619 
1620   Stream.EmitRecord(bitc::METADATA_SUBROUTINE_TYPE, Record, Abbrev);
1621   Record.clear();
1622 }
1623 
1624 void ModuleBitcodeWriter::writeDIFile(const DIFile *N,
1625                                       SmallVectorImpl<uint64_t> &Record,
1626                                       unsigned Abbrev) {
1627   Record.push_back(N->isDistinct());
1628   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
1629   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
1630   if (N->getRawChecksum()) {
1631     Record.push_back(N->getRawChecksum()->Kind);
1632     Record.push_back(VE.getMetadataOrNullID(N->getRawChecksum()->Value));
1633   } else {
1634     // Maintain backwards compatibility with the old internal representation of
1635     // CSK_None in ChecksumKind by writing nulls here when Checksum is None.
1636     Record.push_back(0);
1637     Record.push_back(VE.getMetadataOrNullID(nullptr));
1638   }
1639   auto Source = N->getRawSource();
1640   if (Source)
1641     Record.push_back(VE.getMetadataOrNullID(*Source));
1642 
1643   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
1644   Record.clear();
1645 }
1646 
1647 void ModuleBitcodeWriter::writeDICompileUnit(const DICompileUnit *N,
1648                                              SmallVectorImpl<uint64_t> &Record,
1649                                              unsigned Abbrev) {
1650   assert(N->isDistinct() && "Expected distinct compile units");
1651   Record.push_back(/* IsDistinct */ true);
1652   Record.push_back(N->getSourceLanguage());
1653   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1654   Record.push_back(VE.getMetadataOrNullID(N->getRawProducer()));
1655   Record.push_back(N->isOptimized());
1656   Record.push_back(VE.getMetadataOrNullID(N->getRawFlags()));
1657   Record.push_back(N->getRuntimeVersion());
1658   Record.push_back(VE.getMetadataOrNullID(N->getRawSplitDebugFilename()));
1659   Record.push_back(N->getEmissionKind());
1660   Record.push_back(VE.getMetadataOrNullID(N->getEnumTypes().get()));
1661   Record.push_back(VE.getMetadataOrNullID(N->getRetainedTypes().get()));
1662   Record.push_back(/* subprograms */ 0);
1663   Record.push_back(VE.getMetadataOrNullID(N->getGlobalVariables().get()));
1664   Record.push_back(VE.getMetadataOrNullID(N->getImportedEntities().get()));
1665   Record.push_back(N->getDWOId());
1666   Record.push_back(VE.getMetadataOrNullID(N->getMacros().get()));
1667   Record.push_back(N->getSplitDebugInlining());
1668   Record.push_back(N->getDebugInfoForProfiling());
1669   Record.push_back((unsigned)N->getNameTableKind());
1670   Record.push_back(N->getRangesBaseAddress());
1671   Record.push_back(VE.getMetadataOrNullID(N->getRawSysRoot()));
1672 
1673   Stream.EmitRecord(bitc::METADATA_COMPILE_UNIT, Record, Abbrev);
1674   Record.clear();
1675 }
1676 
1677 void ModuleBitcodeWriter::writeDISubprogram(const DISubprogram *N,
1678                                             SmallVectorImpl<uint64_t> &Record,
1679                                             unsigned Abbrev) {
1680   const uint64_t HasUnitFlag = 1 << 1;
1681   const uint64_t HasSPFlagsFlag = 1 << 2;
1682   Record.push_back(uint64_t(N->isDistinct()) | HasUnitFlag | HasSPFlagsFlag);
1683   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1684   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1685   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1686   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1687   Record.push_back(N->getLine());
1688   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1689   Record.push_back(N->getScopeLine());
1690   Record.push_back(VE.getMetadataOrNullID(N->getContainingType()));
1691   Record.push_back(N->getSPFlags());
1692   Record.push_back(N->getVirtualIndex());
1693   Record.push_back(N->getFlags());
1694   Record.push_back(VE.getMetadataOrNullID(N->getRawUnit()));
1695   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1696   Record.push_back(VE.getMetadataOrNullID(N->getDeclaration()));
1697   Record.push_back(VE.getMetadataOrNullID(N->getRetainedNodes().get()));
1698   Record.push_back(N->getThisAdjustment());
1699   Record.push_back(VE.getMetadataOrNullID(N->getThrownTypes().get()));
1700 
1701   Stream.EmitRecord(bitc::METADATA_SUBPROGRAM, Record, Abbrev);
1702   Record.clear();
1703 }
1704 
1705 void ModuleBitcodeWriter::writeDILexicalBlock(const DILexicalBlock *N,
1706                                               SmallVectorImpl<uint64_t> &Record,
1707                                               unsigned Abbrev) {
1708   Record.push_back(N->isDistinct());
1709   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1710   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1711   Record.push_back(N->getLine());
1712   Record.push_back(N->getColumn());
1713 
1714   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK, Record, Abbrev);
1715   Record.clear();
1716 }
1717 
1718 void ModuleBitcodeWriter::writeDILexicalBlockFile(
1719     const DILexicalBlockFile *N, SmallVectorImpl<uint64_t> &Record,
1720     unsigned Abbrev) {
1721   Record.push_back(N->isDistinct());
1722   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1723   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1724   Record.push_back(N->getDiscriminator());
1725 
1726   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK_FILE, Record, Abbrev);
1727   Record.clear();
1728 }
1729 
1730 void ModuleBitcodeWriter::writeDICommonBlock(const DICommonBlock *N,
1731                                              SmallVectorImpl<uint64_t> &Record,
1732                                              unsigned Abbrev) {
1733   Record.push_back(N->isDistinct());
1734   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1735   Record.push_back(VE.getMetadataOrNullID(N->getDecl()));
1736   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1737   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1738   Record.push_back(N->getLineNo());
1739 
1740   Stream.EmitRecord(bitc::METADATA_COMMON_BLOCK, Record, Abbrev);
1741   Record.clear();
1742 }
1743 
1744 void ModuleBitcodeWriter::writeDINamespace(const DINamespace *N,
1745                                            SmallVectorImpl<uint64_t> &Record,
1746                                            unsigned Abbrev) {
1747   Record.push_back(N->isDistinct() | N->getExportSymbols() << 1);
1748   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1749   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1750 
1751   Stream.EmitRecord(bitc::METADATA_NAMESPACE, Record, Abbrev);
1752   Record.clear();
1753 }
1754 
1755 void ModuleBitcodeWriter::writeDIMacro(const DIMacro *N,
1756                                        SmallVectorImpl<uint64_t> &Record,
1757                                        unsigned Abbrev) {
1758   Record.push_back(N->isDistinct());
1759   Record.push_back(N->getMacinfoType());
1760   Record.push_back(N->getLine());
1761   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1762   Record.push_back(VE.getMetadataOrNullID(N->getRawValue()));
1763 
1764   Stream.EmitRecord(bitc::METADATA_MACRO, Record, Abbrev);
1765   Record.clear();
1766 }
1767 
1768 void ModuleBitcodeWriter::writeDIMacroFile(const DIMacroFile *N,
1769                                            SmallVectorImpl<uint64_t> &Record,
1770                                            unsigned Abbrev) {
1771   Record.push_back(N->isDistinct());
1772   Record.push_back(N->getMacinfoType());
1773   Record.push_back(N->getLine());
1774   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1775   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1776 
1777   Stream.EmitRecord(bitc::METADATA_MACRO_FILE, Record, Abbrev);
1778   Record.clear();
1779 }
1780 
1781 void ModuleBitcodeWriter::writeDIModule(const DIModule *N,
1782                                         SmallVectorImpl<uint64_t> &Record,
1783                                         unsigned Abbrev) {
1784   Record.push_back(N->isDistinct());
1785   for (auto &I : N->operands())
1786     Record.push_back(VE.getMetadataOrNullID(I));
1787 
1788   Stream.EmitRecord(bitc::METADATA_MODULE, Record, Abbrev);
1789   Record.clear();
1790 }
1791 
1792 void ModuleBitcodeWriter::writeDITemplateTypeParameter(
1793     const DITemplateTypeParameter *N, SmallVectorImpl<uint64_t> &Record,
1794     unsigned Abbrev) {
1795   Record.push_back(N->isDistinct());
1796   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1797   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1798   Record.push_back(N->isDefault());
1799 
1800   Stream.EmitRecord(bitc::METADATA_TEMPLATE_TYPE, Record, Abbrev);
1801   Record.clear();
1802 }
1803 
1804 void ModuleBitcodeWriter::writeDITemplateValueParameter(
1805     const DITemplateValueParameter *N, SmallVectorImpl<uint64_t> &Record,
1806     unsigned Abbrev) {
1807   Record.push_back(N->isDistinct());
1808   Record.push_back(N->getTag());
1809   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1810   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1811   Record.push_back(N->isDefault());
1812   Record.push_back(VE.getMetadataOrNullID(N->getValue()));
1813 
1814   Stream.EmitRecord(bitc::METADATA_TEMPLATE_VALUE, Record, Abbrev);
1815   Record.clear();
1816 }
1817 
1818 void ModuleBitcodeWriter::writeDIGlobalVariable(
1819     const DIGlobalVariable *N, SmallVectorImpl<uint64_t> &Record,
1820     unsigned Abbrev) {
1821   const uint64_t Version = 2 << 1;
1822   Record.push_back((uint64_t)N->isDistinct() | Version);
1823   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1824   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1825   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1826   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1827   Record.push_back(N->getLine());
1828   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1829   Record.push_back(N->isLocalToUnit());
1830   Record.push_back(N->isDefinition());
1831   Record.push_back(VE.getMetadataOrNullID(N->getStaticDataMemberDeclaration()));
1832   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams()));
1833   Record.push_back(N->getAlignInBits());
1834 
1835   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR, Record, Abbrev);
1836   Record.clear();
1837 }
1838 
1839 void ModuleBitcodeWriter::writeDILocalVariable(
1840     const DILocalVariable *N, SmallVectorImpl<uint64_t> &Record,
1841     unsigned Abbrev) {
1842   // In order to support all possible bitcode formats in BitcodeReader we need
1843   // to distinguish the following cases:
1844   // 1) Record has no artificial tag (Record[1]),
1845   //   has no obsolete inlinedAt field (Record[9]).
1846   //   In this case Record size will be 8, HasAlignment flag is false.
1847   // 2) Record has artificial tag (Record[1]),
1848   //   has no obsolete inlignedAt field (Record[9]).
1849   //   In this case Record size will be 9, HasAlignment flag is false.
1850   // 3) Record has both artificial tag (Record[1]) and
1851   //   obsolete inlignedAt field (Record[9]).
1852   //   In this case Record size will be 10, HasAlignment flag is false.
1853   // 4) Record has neither artificial tag, nor inlignedAt field, but
1854   //   HasAlignment flag is true and Record[8] contains alignment value.
1855   const uint64_t HasAlignmentFlag = 1 << 1;
1856   Record.push_back((uint64_t)N->isDistinct() | HasAlignmentFlag);
1857   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1858   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1859   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1860   Record.push_back(N->getLine());
1861   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1862   Record.push_back(N->getArg());
1863   Record.push_back(N->getFlags());
1864   Record.push_back(N->getAlignInBits());
1865 
1866   Stream.EmitRecord(bitc::METADATA_LOCAL_VAR, Record, Abbrev);
1867   Record.clear();
1868 }
1869 
1870 void ModuleBitcodeWriter::writeDILabel(
1871     const DILabel *N, SmallVectorImpl<uint64_t> &Record,
1872     unsigned Abbrev) {
1873   Record.push_back((uint64_t)N->isDistinct());
1874   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1875   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1876   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1877   Record.push_back(N->getLine());
1878 
1879   Stream.EmitRecord(bitc::METADATA_LABEL, Record, Abbrev);
1880   Record.clear();
1881 }
1882 
1883 void ModuleBitcodeWriter::writeDIExpression(const DIExpression *N,
1884                                             SmallVectorImpl<uint64_t> &Record,
1885                                             unsigned Abbrev) {
1886   Record.reserve(N->getElements().size() + 1);
1887   const uint64_t Version = 3 << 1;
1888   Record.push_back((uint64_t)N->isDistinct() | Version);
1889   Record.append(N->elements_begin(), N->elements_end());
1890 
1891   Stream.EmitRecord(bitc::METADATA_EXPRESSION, Record, Abbrev);
1892   Record.clear();
1893 }
1894 
1895 void ModuleBitcodeWriter::writeDIGlobalVariableExpression(
1896     const DIGlobalVariableExpression *N, SmallVectorImpl<uint64_t> &Record,
1897     unsigned Abbrev) {
1898   Record.push_back(N->isDistinct());
1899   Record.push_back(VE.getMetadataOrNullID(N->getVariable()));
1900   Record.push_back(VE.getMetadataOrNullID(N->getExpression()));
1901 
1902   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR_EXPR, Record, Abbrev);
1903   Record.clear();
1904 }
1905 
1906 void ModuleBitcodeWriter::writeDIObjCProperty(const DIObjCProperty *N,
1907                                               SmallVectorImpl<uint64_t> &Record,
1908                                               unsigned Abbrev) {
1909   Record.push_back(N->isDistinct());
1910   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1911   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1912   Record.push_back(N->getLine());
1913   Record.push_back(VE.getMetadataOrNullID(N->getRawSetterName()));
1914   Record.push_back(VE.getMetadataOrNullID(N->getRawGetterName()));
1915   Record.push_back(N->getAttributes());
1916   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1917 
1918   Stream.EmitRecord(bitc::METADATA_OBJC_PROPERTY, Record, Abbrev);
1919   Record.clear();
1920 }
1921 
1922 void ModuleBitcodeWriter::writeDIImportedEntity(
1923     const DIImportedEntity *N, SmallVectorImpl<uint64_t> &Record,
1924     unsigned Abbrev) {
1925   Record.push_back(N->isDistinct());
1926   Record.push_back(N->getTag());
1927   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1928   Record.push_back(VE.getMetadataOrNullID(N->getEntity()));
1929   Record.push_back(N->getLine());
1930   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1931   Record.push_back(VE.getMetadataOrNullID(N->getRawFile()));
1932 
1933   Stream.EmitRecord(bitc::METADATA_IMPORTED_ENTITY, Record, Abbrev);
1934   Record.clear();
1935 }
1936 
1937 unsigned ModuleBitcodeWriter::createNamedMetadataAbbrev() {
1938   auto Abbv = std::make_shared<BitCodeAbbrev>();
1939   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
1940   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1941   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1942   return Stream.EmitAbbrev(std::move(Abbv));
1943 }
1944 
1945 void ModuleBitcodeWriter::writeNamedMetadata(
1946     SmallVectorImpl<uint64_t> &Record) {
1947   if (M.named_metadata_empty())
1948     return;
1949 
1950   unsigned Abbrev = createNamedMetadataAbbrev();
1951   for (const NamedMDNode &NMD : M.named_metadata()) {
1952     // Write name.
1953     StringRef Str = NMD.getName();
1954     Record.append(Str.bytes_begin(), Str.bytes_end());
1955     Stream.EmitRecord(bitc::METADATA_NAME, Record, Abbrev);
1956     Record.clear();
1957 
1958     // Write named metadata operands.
1959     for (const MDNode *N : NMD.operands())
1960       Record.push_back(VE.getMetadataID(N));
1961     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
1962     Record.clear();
1963   }
1964 }
1965 
1966 unsigned ModuleBitcodeWriter::createMetadataStringsAbbrev() {
1967   auto Abbv = std::make_shared<BitCodeAbbrev>();
1968   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRINGS));
1969   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // # of strings
1970   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // offset to chars
1971   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
1972   return Stream.EmitAbbrev(std::move(Abbv));
1973 }
1974 
1975 /// Write out a record for MDString.
1976 ///
1977 /// All the metadata strings in a metadata block are emitted in a single
1978 /// record.  The sizes and strings themselves are shoved into a blob.
1979 void ModuleBitcodeWriter::writeMetadataStrings(
1980     ArrayRef<const Metadata *> Strings, SmallVectorImpl<uint64_t> &Record) {
1981   if (Strings.empty())
1982     return;
1983 
1984   // Start the record with the number of strings.
1985   Record.push_back(bitc::METADATA_STRINGS);
1986   Record.push_back(Strings.size());
1987 
1988   // Emit the sizes of the strings in the blob.
1989   SmallString<256> Blob;
1990   {
1991     BitstreamWriter W(Blob);
1992     for (const Metadata *MD : Strings)
1993       W.EmitVBR(cast<MDString>(MD)->getLength(), 6);
1994     W.FlushToWord();
1995   }
1996 
1997   // Add the offset to the strings to the record.
1998   Record.push_back(Blob.size());
1999 
2000   // Add the strings to the blob.
2001   for (const Metadata *MD : Strings)
2002     Blob.append(cast<MDString>(MD)->getString());
2003 
2004   // Emit the final record.
2005   Stream.EmitRecordWithBlob(createMetadataStringsAbbrev(), Record, Blob);
2006   Record.clear();
2007 }
2008 
2009 // Generates an enum to use as an index in the Abbrev array of Metadata record.
2010 enum MetadataAbbrev : unsigned {
2011 #define HANDLE_MDNODE_LEAF(CLASS) CLASS##AbbrevID,
2012 #include "llvm/IR/Metadata.def"
2013   LastPlusOne
2014 };
2015 
2016 void ModuleBitcodeWriter::writeMetadataRecords(
2017     ArrayRef<const Metadata *> MDs, SmallVectorImpl<uint64_t> &Record,
2018     std::vector<unsigned> *MDAbbrevs, std::vector<uint64_t> *IndexPos) {
2019   if (MDs.empty())
2020     return;
2021 
2022   // Initialize MDNode abbreviations.
2023 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
2024 #include "llvm/IR/Metadata.def"
2025 
2026   for (const Metadata *MD : MDs) {
2027     if (IndexPos)
2028       IndexPos->push_back(Stream.GetCurrentBitNo());
2029     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
2030       assert(N->isResolved() && "Expected forward references to be resolved");
2031 
2032       switch (N->getMetadataID()) {
2033       default:
2034         llvm_unreachable("Invalid MDNode subclass");
2035 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
2036   case Metadata::CLASS##Kind:                                                  \
2037     if (MDAbbrevs)                                                             \
2038       write##CLASS(cast<CLASS>(N), Record,                                     \
2039                    (*MDAbbrevs)[MetadataAbbrev::CLASS##AbbrevID]);             \
2040     else                                                                       \
2041       write##CLASS(cast<CLASS>(N), Record, CLASS##Abbrev);                     \
2042     continue;
2043 #include "llvm/IR/Metadata.def"
2044       }
2045     }
2046     writeValueAsMetadata(cast<ValueAsMetadata>(MD), Record);
2047   }
2048 }
2049 
2050 void ModuleBitcodeWriter::writeModuleMetadata() {
2051   if (!VE.hasMDs() && M.named_metadata_empty())
2052     return;
2053 
2054   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 4);
2055   SmallVector<uint64_t, 64> Record;
2056 
2057   // Emit all abbrevs upfront, so that the reader can jump in the middle of the
2058   // block and load any metadata.
2059   std::vector<unsigned> MDAbbrevs;
2060 
2061   MDAbbrevs.resize(MetadataAbbrev::LastPlusOne);
2062   MDAbbrevs[MetadataAbbrev::DILocationAbbrevID] = createDILocationAbbrev();
2063   MDAbbrevs[MetadataAbbrev::GenericDINodeAbbrevID] =
2064       createGenericDINodeAbbrev();
2065 
2066   auto Abbv = std::make_shared<BitCodeAbbrev>();
2067   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX_OFFSET));
2068   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2069   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2070   unsigned OffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2071 
2072   Abbv = std::make_shared<BitCodeAbbrev>();
2073   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX));
2074   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2075   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2076   unsigned IndexAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2077 
2078   // Emit MDStrings together upfront.
2079   writeMetadataStrings(VE.getMDStrings(), Record);
2080 
2081   // We only emit an index for the metadata record if we have more than a given
2082   // (naive) threshold of metadatas, otherwise it is not worth it.
2083   if (VE.getNonMDStrings().size() > IndexThreshold) {
2084     // Write a placeholder value in for the offset of the metadata index,
2085     // which is written after the records, so that it can include
2086     // the offset of each entry. The placeholder offset will be
2087     // updated after all records are emitted.
2088     uint64_t Vals[] = {0, 0};
2089     Stream.EmitRecord(bitc::METADATA_INDEX_OFFSET, Vals, OffsetAbbrev);
2090   }
2091 
2092   // Compute and save the bit offset to the current position, which will be
2093   // patched when we emit the index later. We can simply subtract the 64-bit
2094   // fixed size from the current bit number to get the location to backpatch.
2095   uint64_t IndexOffsetRecordBitPos = Stream.GetCurrentBitNo();
2096 
2097   // This index will contain the bitpos for each individual record.
2098   std::vector<uint64_t> IndexPos;
2099   IndexPos.reserve(VE.getNonMDStrings().size());
2100 
2101   // Write all the records
2102   writeMetadataRecords(VE.getNonMDStrings(), Record, &MDAbbrevs, &IndexPos);
2103 
2104   if (VE.getNonMDStrings().size() > IndexThreshold) {
2105     // Now that we have emitted all the records we will emit the index. But
2106     // first
2107     // backpatch the forward reference so that the reader can skip the records
2108     // efficiently.
2109     Stream.BackpatchWord64(IndexOffsetRecordBitPos - 64,
2110                            Stream.GetCurrentBitNo() - IndexOffsetRecordBitPos);
2111 
2112     // Delta encode the index.
2113     uint64_t PreviousValue = IndexOffsetRecordBitPos;
2114     for (auto &Elt : IndexPos) {
2115       auto EltDelta = Elt - PreviousValue;
2116       PreviousValue = Elt;
2117       Elt = EltDelta;
2118     }
2119     // Emit the index record.
2120     Stream.EmitRecord(bitc::METADATA_INDEX, IndexPos, IndexAbbrev);
2121     IndexPos.clear();
2122   }
2123 
2124   // Write the named metadata now.
2125   writeNamedMetadata(Record);
2126 
2127   auto AddDeclAttachedMetadata = [&](const GlobalObject &GO) {
2128     SmallVector<uint64_t, 4> Record;
2129     Record.push_back(VE.getValueID(&GO));
2130     pushGlobalMetadataAttachment(Record, GO);
2131     Stream.EmitRecord(bitc::METADATA_GLOBAL_DECL_ATTACHMENT, Record);
2132   };
2133   for (const Function &F : M)
2134     if (F.isDeclaration() && F.hasMetadata())
2135       AddDeclAttachedMetadata(F);
2136   // FIXME: Only store metadata for declarations here, and move data for global
2137   // variable definitions to a separate block (PR28134).
2138   for (const GlobalVariable &GV : M.globals())
2139     if (GV.hasMetadata())
2140       AddDeclAttachedMetadata(GV);
2141 
2142   Stream.ExitBlock();
2143 }
2144 
2145 void ModuleBitcodeWriter::writeFunctionMetadata(const Function &F) {
2146   if (!VE.hasMDs())
2147     return;
2148 
2149   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
2150   SmallVector<uint64_t, 64> Record;
2151   writeMetadataStrings(VE.getMDStrings(), Record);
2152   writeMetadataRecords(VE.getNonMDStrings(), Record);
2153   Stream.ExitBlock();
2154 }
2155 
2156 void ModuleBitcodeWriter::pushGlobalMetadataAttachment(
2157     SmallVectorImpl<uint64_t> &Record, const GlobalObject &GO) {
2158   // [n x [id, mdnode]]
2159   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2160   GO.getAllMetadata(MDs);
2161   for (const auto &I : MDs) {
2162     Record.push_back(I.first);
2163     Record.push_back(VE.getMetadataID(I.second));
2164   }
2165 }
2166 
2167 void ModuleBitcodeWriter::writeFunctionMetadataAttachment(const Function &F) {
2168   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
2169 
2170   SmallVector<uint64_t, 64> Record;
2171 
2172   if (F.hasMetadata()) {
2173     pushGlobalMetadataAttachment(Record, F);
2174     Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2175     Record.clear();
2176   }
2177 
2178   // Write metadata attachments
2179   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
2180   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2181   for (const BasicBlock &BB : F)
2182     for (const Instruction &I : BB) {
2183       MDs.clear();
2184       I.getAllMetadataOtherThanDebugLoc(MDs);
2185 
2186       // If no metadata, ignore instruction.
2187       if (MDs.empty()) continue;
2188 
2189       Record.push_back(VE.getInstructionID(&I));
2190 
2191       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
2192         Record.push_back(MDs[i].first);
2193         Record.push_back(VE.getMetadataID(MDs[i].second));
2194       }
2195       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2196       Record.clear();
2197     }
2198 
2199   Stream.ExitBlock();
2200 }
2201 
2202 void ModuleBitcodeWriter::writeModuleMetadataKinds() {
2203   SmallVector<uint64_t, 64> Record;
2204 
2205   // Write metadata kinds
2206   // METADATA_KIND - [n x [id, name]]
2207   SmallVector<StringRef, 8> Names;
2208   M.getMDKindNames(Names);
2209 
2210   if (Names.empty()) return;
2211 
2212   Stream.EnterSubblock(bitc::METADATA_KIND_BLOCK_ID, 3);
2213 
2214   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
2215     Record.push_back(MDKindID);
2216     StringRef KName = Names[MDKindID];
2217     Record.append(KName.begin(), KName.end());
2218 
2219     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
2220     Record.clear();
2221   }
2222 
2223   Stream.ExitBlock();
2224 }
2225 
2226 void ModuleBitcodeWriter::writeOperandBundleTags() {
2227   // Write metadata kinds
2228   //
2229   // OPERAND_BUNDLE_TAGS_BLOCK_ID : N x OPERAND_BUNDLE_TAG
2230   //
2231   // OPERAND_BUNDLE_TAG - [strchr x N]
2232 
2233   SmallVector<StringRef, 8> Tags;
2234   M.getOperandBundleTags(Tags);
2235 
2236   if (Tags.empty())
2237     return;
2238 
2239   Stream.EnterSubblock(bitc::OPERAND_BUNDLE_TAGS_BLOCK_ID, 3);
2240 
2241   SmallVector<uint64_t, 64> Record;
2242 
2243   for (auto Tag : Tags) {
2244     Record.append(Tag.begin(), Tag.end());
2245 
2246     Stream.EmitRecord(bitc::OPERAND_BUNDLE_TAG, Record, 0);
2247     Record.clear();
2248   }
2249 
2250   Stream.ExitBlock();
2251 }
2252 
2253 void ModuleBitcodeWriter::writeSyncScopeNames() {
2254   SmallVector<StringRef, 8> SSNs;
2255   M.getContext().getSyncScopeNames(SSNs);
2256   if (SSNs.empty())
2257     return;
2258 
2259   Stream.EnterSubblock(bitc::SYNC_SCOPE_NAMES_BLOCK_ID, 2);
2260 
2261   SmallVector<uint64_t, 64> Record;
2262   for (auto SSN : SSNs) {
2263     Record.append(SSN.begin(), SSN.end());
2264     Stream.EmitRecord(bitc::SYNC_SCOPE_NAME, Record, 0);
2265     Record.clear();
2266   }
2267 
2268   Stream.ExitBlock();
2269 }
2270 
2271 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
2272   if ((int64_t)V >= 0)
2273     Vals.push_back(V << 1);
2274   else
2275     Vals.push_back((-V << 1) | 1);
2276 }
2277 
2278 void ModuleBitcodeWriter::writeConstants(unsigned FirstVal, unsigned LastVal,
2279                                          bool isGlobal) {
2280   if (FirstVal == LastVal) return;
2281 
2282   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
2283 
2284   unsigned AggregateAbbrev = 0;
2285   unsigned String8Abbrev = 0;
2286   unsigned CString7Abbrev = 0;
2287   unsigned CString6Abbrev = 0;
2288   // If this is a constant pool for the module, emit module-specific abbrevs.
2289   if (isGlobal) {
2290     // Abbrev for CST_CODE_AGGREGATE.
2291     auto Abbv = std::make_shared<BitCodeAbbrev>();
2292     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
2293     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2294     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
2295     AggregateAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2296 
2297     // Abbrev for CST_CODE_STRING.
2298     Abbv = std::make_shared<BitCodeAbbrev>();
2299     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
2300     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2301     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2302     String8Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2303     // Abbrev for CST_CODE_CSTRING.
2304     Abbv = std::make_shared<BitCodeAbbrev>();
2305     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2306     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2307     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2308     CString7Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2309     // Abbrev for CST_CODE_CSTRING.
2310     Abbv = std::make_shared<BitCodeAbbrev>();
2311     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2312     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2313     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2314     CString6Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2315   }
2316 
2317   SmallVector<uint64_t, 64> Record;
2318 
2319   const ValueEnumerator::ValueList &Vals = VE.getValues();
2320   Type *LastTy = nullptr;
2321   for (unsigned i = FirstVal; i != LastVal; ++i) {
2322     const Value *V = Vals[i].first;
2323     // If we need to switch types, do so now.
2324     if (V->getType() != LastTy) {
2325       LastTy = V->getType();
2326       Record.push_back(VE.getTypeID(LastTy));
2327       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
2328                         CONSTANTS_SETTYPE_ABBREV);
2329       Record.clear();
2330     }
2331 
2332     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
2333       Record.push_back(unsigned(IA->hasSideEffects()) |
2334                        unsigned(IA->isAlignStack()) << 1 |
2335                        unsigned(IA->getDialect()&1) << 2);
2336 
2337       // Add the asm string.
2338       const std::string &AsmStr = IA->getAsmString();
2339       Record.push_back(AsmStr.size());
2340       Record.append(AsmStr.begin(), AsmStr.end());
2341 
2342       // Add the constraint string.
2343       const std::string &ConstraintStr = IA->getConstraintString();
2344       Record.push_back(ConstraintStr.size());
2345       Record.append(ConstraintStr.begin(), ConstraintStr.end());
2346       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
2347       Record.clear();
2348       continue;
2349     }
2350     const Constant *C = cast<Constant>(V);
2351     unsigned Code = -1U;
2352     unsigned AbbrevToUse = 0;
2353     if (C->isNullValue()) {
2354       Code = bitc::CST_CODE_NULL;
2355     } else if (isa<UndefValue>(C)) {
2356       Code = bitc::CST_CODE_UNDEF;
2357     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
2358       if (IV->getBitWidth() <= 64) {
2359         uint64_t V = IV->getSExtValue();
2360         emitSignedInt64(Record, V);
2361         Code = bitc::CST_CODE_INTEGER;
2362         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
2363       } else {                             // Wide integers, > 64 bits in size.
2364         // We have an arbitrary precision integer value to write whose
2365         // bit width is > 64. However, in canonical unsigned integer
2366         // format it is likely that the high bits are going to be zero.
2367         // So, we only write the number of active words.
2368         unsigned NWords = IV->getValue().getActiveWords();
2369         const uint64_t *RawWords = IV->getValue().getRawData();
2370         for (unsigned i = 0; i != NWords; ++i) {
2371           emitSignedInt64(Record, RawWords[i]);
2372         }
2373         Code = bitc::CST_CODE_WIDE_INTEGER;
2374       }
2375     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
2376       Code = bitc::CST_CODE_FLOAT;
2377       Type *Ty = CFP->getType();
2378       if (Ty->isHalfTy() || Ty->isFloatTy() || Ty->isDoubleTy()) {
2379         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
2380       } else if (Ty->isX86_FP80Ty()) {
2381         // api needed to prevent premature destruction
2382         // bits are not in the same order as a normal i80 APInt, compensate.
2383         APInt api = CFP->getValueAPF().bitcastToAPInt();
2384         const uint64_t *p = api.getRawData();
2385         Record.push_back((p[1] << 48) | (p[0] >> 16));
2386         Record.push_back(p[0] & 0xffffLL);
2387       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
2388         APInt api = CFP->getValueAPF().bitcastToAPInt();
2389         const uint64_t *p = api.getRawData();
2390         Record.push_back(p[0]);
2391         Record.push_back(p[1]);
2392       } else {
2393         assert(0 && "Unknown FP type!");
2394       }
2395     } else if (isa<ConstantDataSequential>(C) &&
2396                cast<ConstantDataSequential>(C)->isString()) {
2397       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
2398       // Emit constant strings specially.
2399       unsigned NumElts = Str->getNumElements();
2400       // If this is a null-terminated string, use the denser CSTRING encoding.
2401       if (Str->isCString()) {
2402         Code = bitc::CST_CODE_CSTRING;
2403         --NumElts;  // Don't encode the null, which isn't allowed by char6.
2404       } else {
2405         Code = bitc::CST_CODE_STRING;
2406         AbbrevToUse = String8Abbrev;
2407       }
2408       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
2409       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
2410       for (unsigned i = 0; i != NumElts; ++i) {
2411         unsigned char V = Str->getElementAsInteger(i);
2412         Record.push_back(V);
2413         isCStr7 &= (V & 128) == 0;
2414         if (isCStrChar6)
2415           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
2416       }
2417 
2418       if (isCStrChar6)
2419         AbbrevToUse = CString6Abbrev;
2420       else if (isCStr7)
2421         AbbrevToUse = CString7Abbrev;
2422     } else if (const ConstantDataSequential *CDS =
2423                   dyn_cast<ConstantDataSequential>(C)) {
2424       Code = bitc::CST_CODE_DATA;
2425       Type *EltTy = CDS->getType()->getElementType();
2426       if (isa<IntegerType>(EltTy)) {
2427         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2428           Record.push_back(CDS->getElementAsInteger(i));
2429       } else {
2430         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2431           Record.push_back(
2432               CDS->getElementAsAPFloat(i).bitcastToAPInt().getLimitedValue());
2433       }
2434     } else if (isa<ConstantAggregate>(C)) {
2435       Code = bitc::CST_CODE_AGGREGATE;
2436       for (const Value *Op : C->operands())
2437         Record.push_back(VE.getValueID(Op));
2438       AbbrevToUse = AggregateAbbrev;
2439     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
2440       switch (CE->getOpcode()) {
2441       default:
2442         if (Instruction::isCast(CE->getOpcode())) {
2443           Code = bitc::CST_CODE_CE_CAST;
2444           Record.push_back(getEncodedCastOpcode(CE->getOpcode()));
2445           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2446           Record.push_back(VE.getValueID(C->getOperand(0)));
2447           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
2448         } else {
2449           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
2450           Code = bitc::CST_CODE_CE_BINOP;
2451           Record.push_back(getEncodedBinaryOpcode(CE->getOpcode()));
2452           Record.push_back(VE.getValueID(C->getOperand(0)));
2453           Record.push_back(VE.getValueID(C->getOperand(1)));
2454           uint64_t Flags = getOptimizationFlags(CE);
2455           if (Flags != 0)
2456             Record.push_back(Flags);
2457         }
2458         break;
2459       case Instruction::FNeg: {
2460         assert(CE->getNumOperands() == 1 && "Unknown constant expr!");
2461         Code = bitc::CST_CODE_CE_UNOP;
2462         Record.push_back(getEncodedUnaryOpcode(CE->getOpcode()));
2463         Record.push_back(VE.getValueID(C->getOperand(0)));
2464         uint64_t Flags = getOptimizationFlags(CE);
2465         if (Flags != 0)
2466           Record.push_back(Flags);
2467         break;
2468       }
2469       case Instruction::GetElementPtr: {
2470         Code = bitc::CST_CODE_CE_GEP;
2471         const auto *GO = cast<GEPOperator>(C);
2472         Record.push_back(VE.getTypeID(GO->getSourceElementType()));
2473         if (Optional<unsigned> Idx = GO->getInRangeIndex()) {
2474           Code = bitc::CST_CODE_CE_GEP_WITH_INRANGE_INDEX;
2475           Record.push_back((*Idx << 1) | GO->isInBounds());
2476         } else if (GO->isInBounds())
2477           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
2478         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
2479           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
2480           Record.push_back(VE.getValueID(C->getOperand(i)));
2481         }
2482         break;
2483       }
2484       case Instruction::Select:
2485         Code = bitc::CST_CODE_CE_SELECT;
2486         Record.push_back(VE.getValueID(C->getOperand(0)));
2487         Record.push_back(VE.getValueID(C->getOperand(1)));
2488         Record.push_back(VE.getValueID(C->getOperand(2)));
2489         break;
2490       case Instruction::ExtractElement:
2491         Code = bitc::CST_CODE_CE_EXTRACTELT;
2492         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2493         Record.push_back(VE.getValueID(C->getOperand(0)));
2494         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
2495         Record.push_back(VE.getValueID(C->getOperand(1)));
2496         break;
2497       case Instruction::InsertElement:
2498         Code = bitc::CST_CODE_CE_INSERTELT;
2499         Record.push_back(VE.getValueID(C->getOperand(0)));
2500         Record.push_back(VE.getValueID(C->getOperand(1)));
2501         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
2502         Record.push_back(VE.getValueID(C->getOperand(2)));
2503         break;
2504       case Instruction::ShuffleVector:
2505         // If the return type and argument types are the same, this is a
2506         // standard shufflevector instruction.  If the types are different,
2507         // then the shuffle is widening or truncating the input vectors, and
2508         // the argument type must also be encoded.
2509         if (C->getType() == C->getOperand(0)->getType()) {
2510           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
2511         } else {
2512           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
2513           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2514         }
2515         Record.push_back(VE.getValueID(C->getOperand(0)));
2516         Record.push_back(VE.getValueID(C->getOperand(1)));
2517         Record.push_back(VE.getValueID(C->getOperand(2)));
2518         break;
2519       case Instruction::ICmp:
2520       case Instruction::FCmp:
2521         Code = bitc::CST_CODE_CE_CMP;
2522         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2523         Record.push_back(VE.getValueID(C->getOperand(0)));
2524         Record.push_back(VE.getValueID(C->getOperand(1)));
2525         Record.push_back(CE->getPredicate());
2526         break;
2527       }
2528     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
2529       Code = bitc::CST_CODE_BLOCKADDRESS;
2530       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
2531       Record.push_back(VE.getValueID(BA->getFunction()));
2532       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
2533     } else {
2534 #ifndef NDEBUG
2535       C->dump();
2536 #endif
2537       llvm_unreachable("Unknown constant!");
2538     }
2539     Stream.EmitRecord(Code, Record, AbbrevToUse);
2540     Record.clear();
2541   }
2542 
2543   Stream.ExitBlock();
2544 }
2545 
2546 void ModuleBitcodeWriter::writeModuleConstants() {
2547   const ValueEnumerator::ValueList &Vals = VE.getValues();
2548 
2549   // Find the first constant to emit, which is the first non-globalvalue value.
2550   // We know globalvalues have been emitted by WriteModuleInfo.
2551   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
2552     if (!isa<GlobalValue>(Vals[i].first)) {
2553       writeConstants(i, Vals.size(), true);
2554       return;
2555     }
2556   }
2557 }
2558 
2559 /// pushValueAndType - The file has to encode both the value and type id for
2560 /// many values, because we need to know what type to create for forward
2561 /// references.  However, most operands are not forward references, so this type
2562 /// field is not needed.
2563 ///
2564 /// This function adds V's value ID to Vals.  If the value ID is higher than the
2565 /// instruction ID, then it is a forward reference, and it also includes the
2566 /// type ID.  The value ID that is written is encoded relative to the InstID.
2567 bool ModuleBitcodeWriter::pushValueAndType(const Value *V, unsigned InstID,
2568                                            SmallVectorImpl<unsigned> &Vals) {
2569   unsigned ValID = VE.getValueID(V);
2570   // Make encoding relative to the InstID.
2571   Vals.push_back(InstID - ValID);
2572   if (ValID >= InstID) {
2573     Vals.push_back(VE.getTypeID(V->getType()));
2574     return true;
2575   }
2576   return false;
2577 }
2578 
2579 void ModuleBitcodeWriter::writeOperandBundles(ImmutableCallSite CS,
2580                                               unsigned InstID) {
2581   SmallVector<unsigned, 64> Record;
2582   LLVMContext &C = CS.getInstruction()->getContext();
2583 
2584   for (unsigned i = 0, e = CS.getNumOperandBundles(); i != e; ++i) {
2585     const auto &Bundle = CS.getOperandBundleAt(i);
2586     Record.push_back(C.getOperandBundleTagID(Bundle.getTagName()));
2587 
2588     for (auto &Input : Bundle.Inputs)
2589       pushValueAndType(Input, InstID, Record);
2590 
2591     Stream.EmitRecord(bitc::FUNC_CODE_OPERAND_BUNDLE, Record);
2592     Record.clear();
2593   }
2594 }
2595 
2596 /// pushValue - Like pushValueAndType, but where the type of the value is
2597 /// omitted (perhaps it was already encoded in an earlier operand).
2598 void ModuleBitcodeWriter::pushValue(const Value *V, unsigned InstID,
2599                                     SmallVectorImpl<unsigned> &Vals) {
2600   unsigned ValID = VE.getValueID(V);
2601   Vals.push_back(InstID - ValID);
2602 }
2603 
2604 void ModuleBitcodeWriter::pushValueSigned(const Value *V, unsigned InstID,
2605                                           SmallVectorImpl<uint64_t> &Vals) {
2606   unsigned ValID = VE.getValueID(V);
2607   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
2608   emitSignedInt64(Vals, diff);
2609 }
2610 
2611 /// WriteInstruction - Emit an instruction to the specified stream.
2612 void ModuleBitcodeWriter::writeInstruction(const Instruction &I,
2613                                            unsigned InstID,
2614                                            SmallVectorImpl<unsigned> &Vals) {
2615   unsigned Code = 0;
2616   unsigned AbbrevToUse = 0;
2617   VE.setInstructionID(&I);
2618   switch (I.getOpcode()) {
2619   default:
2620     if (Instruction::isCast(I.getOpcode())) {
2621       Code = bitc::FUNC_CODE_INST_CAST;
2622       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2623         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
2624       Vals.push_back(VE.getTypeID(I.getType()));
2625       Vals.push_back(getEncodedCastOpcode(I.getOpcode()));
2626     } else {
2627       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
2628       Code = bitc::FUNC_CODE_INST_BINOP;
2629       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2630         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
2631       pushValue(I.getOperand(1), InstID, Vals);
2632       Vals.push_back(getEncodedBinaryOpcode(I.getOpcode()));
2633       uint64_t Flags = getOptimizationFlags(&I);
2634       if (Flags != 0) {
2635         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
2636           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
2637         Vals.push_back(Flags);
2638       }
2639     }
2640     break;
2641   case Instruction::FNeg: {
2642     Code = bitc::FUNC_CODE_INST_UNOP;
2643     if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2644       AbbrevToUse = FUNCTION_INST_UNOP_ABBREV;
2645     Vals.push_back(getEncodedUnaryOpcode(I.getOpcode()));
2646     uint64_t Flags = getOptimizationFlags(&I);
2647     if (Flags != 0) {
2648       if (AbbrevToUse == FUNCTION_INST_UNOP_ABBREV)
2649         AbbrevToUse = FUNCTION_INST_UNOP_FLAGS_ABBREV;
2650       Vals.push_back(Flags);
2651     }
2652     break;
2653   }
2654   case Instruction::GetElementPtr: {
2655     Code = bitc::FUNC_CODE_INST_GEP;
2656     AbbrevToUse = FUNCTION_INST_GEP_ABBREV;
2657     auto &GEPInst = cast<GetElementPtrInst>(I);
2658     Vals.push_back(GEPInst.isInBounds());
2659     Vals.push_back(VE.getTypeID(GEPInst.getSourceElementType()));
2660     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
2661       pushValueAndType(I.getOperand(i), InstID, Vals);
2662     break;
2663   }
2664   case Instruction::ExtractValue: {
2665     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
2666     pushValueAndType(I.getOperand(0), InstID, Vals);
2667     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
2668     Vals.append(EVI->idx_begin(), EVI->idx_end());
2669     break;
2670   }
2671   case Instruction::InsertValue: {
2672     Code = bitc::FUNC_CODE_INST_INSERTVAL;
2673     pushValueAndType(I.getOperand(0), InstID, Vals);
2674     pushValueAndType(I.getOperand(1), InstID, Vals);
2675     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
2676     Vals.append(IVI->idx_begin(), IVI->idx_end());
2677     break;
2678   }
2679   case Instruction::Select: {
2680     Code = bitc::FUNC_CODE_INST_VSELECT;
2681     pushValueAndType(I.getOperand(1), InstID, Vals);
2682     pushValue(I.getOperand(2), InstID, Vals);
2683     pushValueAndType(I.getOperand(0), InstID, Vals);
2684     uint64_t Flags = getOptimizationFlags(&I);
2685     if (Flags != 0)
2686       Vals.push_back(Flags);
2687     break;
2688   }
2689   case Instruction::ExtractElement:
2690     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
2691     pushValueAndType(I.getOperand(0), InstID, Vals);
2692     pushValueAndType(I.getOperand(1), InstID, Vals);
2693     break;
2694   case Instruction::InsertElement:
2695     Code = bitc::FUNC_CODE_INST_INSERTELT;
2696     pushValueAndType(I.getOperand(0), InstID, Vals);
2697     pushValue(I.getOperand(1), InstID, Vals);
2698     pushValueAndType(I.getOperand(2), InstID, Vals);
2699     break;
2700   case Instruction::ShuffleVector:
2701     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
2702     pushValueAndType(I.getOperand(0), InstID, Vals);
2703     pushValue(I.getOperand(1), InstID, Vals);
2704     pushValue(I.getOperand(2), InstID, Vals);
2705     break;
2706   case Instruction::ICmp:
2707   case Instruction::FCmp: {
2708     // compare returning Int1Ty or vector of Int1Ty
2709     Code = bitc::FUNC_CODE_INST_CMP2;
2710     pushValueAndType(I.getOperand(0), InstID, Vals);
2711     pushValue(I.getOperand(1), InstID, Vals);
2712     Vals.push_back(cast<CmpInst>(I).getPredicate());
2713     uint64_t Flags = getOptimizationFlags(&I);
2714     if (Flags != 0)
2715       Vals.push_back(Flags);
2716     break;
2717   }
2718 
2719   case Instruction::Ret:
2720     {
2721       Code = bitc::FUNC_CODE_INST_RET;
2722       unsigned NumOperands = I.getNumOperands();
2723       if (NumOperands == 0)
2724         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
2725       else if (NumOperands == 1) {
2726         if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2727           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
2728       } else {
2729         for (unsigned i = 0, e = NumOperands; i != e; ++i)
2730           pushValueAndType(I.getOperand(i), InstID, Vals);
2731       }
2732     }
2733     break;
2734   case Instruction::Br:
2735     {
2736       Code = bitc::FUNC_CODE_INST_BR;
2737       const BranchInst &II = cast<BranchInst>(I);
2738       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
2739       if (II.isConditional()) {
2740         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
2741         pushValue(II.getCondition(), InstID, Vals);
2742       }
2743     }
2744     break;
2745   case Instruction::Switch:
2746     {
2747       Code = bitc::FUNC_CODE_INST_SWITCH;
2748       const SwitchInst &SI = cast<SwitchInst>(I);
2749       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
2750       pushValue(SI.getCondition(), InstID, Vals);
2751       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
2752       for (auto Case : SI.cases()) {
2753         Vals.push_back(VE.getValueID(Case.getCaseValue()));
2754         Vals.push_back(VE.getValueID(Case.getCaseSuccessor()));
2755       }
2756     }
2757     break;
2758   case Instruction::IndirectBr:
2759     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
2760     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2761     // Encode the address operand as relative, but not the basic blocks.
2762     pushValue(I.getOperand(0), InstID, Vals);
2763     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
2764       Vals.push_back(VE.getValueID(I.getOperand(i)));
2765     break;
2766 
2767   case Instruction::Invoke: {
2768     const InvokeInst *II = cast<InvokeInst>(&I);
2769     const Value *Callee = II->getCalledValue();
2770     FunctionType *FTy = II->getFunctionType();
2771 
2772     if (II->hasOperandBundles())
2773       writeOperandBundles(II, InstID);
2774 
2775     Code = bitc::FUNC_CODE_INST_INVOKE;
2776 
2777     Vals.push_back(VE.getAttributeListID(II->getAttributes()));
2778     Vals.push_back(II->getCallingConv() | 1 << 13);
2779     Vals.push_back(VE.getValueID(II->getNormalDest()));
2780     Vals.push_back(VE.getValueID(II->getUnwindDest()));
2781     Vals.push_back(VE.getTypeID(FTy));
2782     pushValueAndType(Callee, InstID, Vals);
2783 
2784     // Emit value #'s for the fixed parameters.
2785     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
2786       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
2787 
2788     // Emit type/value pairs for varargs params.
2789     if (FTy->isVarArg()) {
2790       for (unsigned i = FTy->getNumParams(), e = II->getNumArgOperands();
2791            i != e; ++i)
2792         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
2793     }
2794     break;
2795   }
2796   case Instruction::Resume:
2797     Code = bitc::FUNC_CODE_INST_RESUME;
2798     pushValueAndType(I.getOperand(0), InstID, Vals);
2799     break;
2800   case Instruction::CleanupRet: {
2801     Code = bitc::FUNC_CODE_INST_CLEANUPRET;
2802     const auto &CRI = cast<CleanupReturnInst>(I);
2803     pushValue(CRI.getCleanupPad(), InstID, Vals);
2804     if (CRI.hasUnwindDest())
2805       Vals.push_back(VE.getValueID(CRI.getUnwindDest()));
2806     break;
2807   }
2808   case Instruction::CatchRet: {
2809     Code = bitc::FUNC_CODE_INST_CATCHRET;
2810     const auto &CRI = cast<CatchReturnInst>(I);
2811     pushValue(CRI.getCatchPad(), InstID, Vals);
2812     Vals.push_back(VE.getValueID(CRI.getSuccessor()));
2813     break;
2814   }
2815   case Instruction::CleanupPad:
2816   case Instruction::CatchPad: {
2817     const auto &FuncletPad = cast<FuncletPadInst>(I);
2818     Code = isa<CatchPadInst>(FuncletPad) ? bitc::FUNC_CODE_INST_CATCHPAD
2819                                          : bitc::FUNC_CODE_INST_CLEANUPPAD;
2820     pushValue(FuncletPad.getParentPad(), InstID, Vals);
2821 
2822     unsigned NumArgOperands = FuncletPad.getNumArgOperands();
2823     Vals.push_back(NumArgOperands);
2824     for (unsigned Op = 0; Op != NumArgOperands; ++Op)
2825       pushValueAndType(FuncletPad.getArgOperand(Op), InstID, Vals);
2826     break;
2827   }
2828   case Instruction::CatchSwitch: {
2829     Code = bitc::FUNC_CODE_INST_CATCHSWITCH;
2830     const auto &CatchSwitch = cast<CatchSwitchInst>(I);
2831 
2832     pushValue(CatchSwitch.getParentPad(), InstID, Vals);
2833 
2834     unsigned NumHandlers = CatchSwitch.getNumHandlers();
2835     Vals.push_back(NumHandlers);
2836     for (const BasicBlock *CatchPadBB : CatchSwitch.handlers())
2837       Vals.push_back(VE.getValueID(CatchPadBB));
2838 
2839     if (CatchSwitch.hasUnwindDest())
2840       Vals.push_back(VE.getValueID(CatchSwitch.getUnwindDest()));
2841     break;
2842   }
2843   case Instruction::CallBr: {
2844     const CallBrInst *CBI = cast<CallBrInst>(&I);
2845     const Value *Callee = CBI->getCalledValue();
2846     FunctionType *FTy = CBI->getFunctionType();
2847 
2848     if (CBI->hasOperandBundles())
2849       writeOperandBundles(CBI, InstID);
2850 
2851     Code = bitc::FUNC_CODE_INST_CALLBR;
2852 
2853     Vals.push_back(VE.getAttributeListID(CBI->getAttributes()));
2854 
2855     Vals.push_back(CBI->getCallingConv() << bitc::CALL_CCONV |
2856                    1 << bitc::CALL_EXPLICIT_TYPE);
2857 
2858     Vals.push_back(VE.getValueID(CBI->getDefaultDest()));
2859     Vals.push_back(CBI->getNumIndirectDests());
2860     for (unsigned i = 0, e = CBI->getNumIndirectDests(); i != e; ++i)
2861       Vals.push_back(VE.getValueID(CBI->getIndirectDest(i)));
2862 
2863     Vals.push_back(VE.getTypeID(FTy));
2864     pushValueAndType(Callee, InstID, Vals);
2865 
2866     // Emit value #'s for the fixed parameters.
2867     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
2868       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
2869 
2870     // Emit type/value pairs for varargs params.
2871     if (FTy->isVarArg()) {
2872       for (unsigned i = FTy->getNumParams(), e = CBI->getNumArgOperands();
2873            i != e; ++i)
2874         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
2875     }
2876     break;
2877   }
2878   case Instruction::Unreachable:
2879     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
2880     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
2881     break;
2882 
2883   case Instruction::PHI: {
2884     const PHINode &PN = cast<PHINode>(I);
2885     Code = bitc::FUNC_CODE_INST_PHI;
2886     // With the newer instruction encoding, forward references could give
2887     // negative valued IDs.  This is most common for PHIs, so we use
2888     // signed VBRs.
2889     SmallVector<uint64_t, 128> Vals64;
2890     Vals64.push_back(VE.getTypeID(PN.getType()));
2891     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
2892       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64);
2893       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
2894     }
2895 
2896     uint64_t Flags = getOptimizationFlags(&I);
2897     if (Flags != 0)
2898       Vals64.push_back(Flags);
2899 
2900     // Emit a Vals64 vector and exit.
2901     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
2902     Vals64.clear();
2903     return;
2904   }
2905 
2906   case Instruction::LandingPad: {
2907     const LandingPadInst &LP = cast<LandingPadInst>(I);
2908     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
2909     Vals.push_back(VE.getTypeID(LP.getType()));
2910     Vals.push_back(LP.isCleanup());
2911     Vals.push_back(LP.getNumClauses());
2912     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
2913       if (LP.isCatch(I))
2914         Vals.push_back(LandingPadInst::Catch);
2915       else
2916         Vals.push_back(LandingPadInst::Filter);
2917       pushValueAndType(LP.getClause(I), InstID, Vals);
2918     }
2919     break;
2920   }
2921 
2922   case Instruction::Alloca: {
2923     Code = bitc::FUNC_CODE_INST_ALLOCA;
2924     const AllocaInst &AI = cast<AllocaInst>(I);
2925     Vals.push_back(VE.getTypeID(AI.getAllocatedType()));
2926     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2927     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
2928     unsigned AlignRecord = Log2_32(AI.getAlignment()) + 1;
2929     assert(Log2_32(Value::MaximumAlignment) + 1 < 1 << 5 &&
2930            "not enough bits for maximum alignment");
2931     assert(AlignRecord < 1 << 5 && "alignment greater than 1 << 64");
2932     AlignRecord |= AI.isUsedWithInAlloca() << 5;
2933     AlignRecord |= 1 << 6;
2934     AlignRecord |= AI.isSwiftError() << 7;
2935     Vals.push_back(AlignRecord);
2936     break;
2937   }
2938 
2939   case Instruction::Load:
2940     if (cast<LoadInst>(I).isAtomic()) {
2941       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
2942       pushValueAndType(I.getOperand(0), InstID, Vals);
2943     } else {
2944       Code = bitc::FUNC_CODE_INST_LOAD;
2945       if (!pushValueAndType(I.getOperand(0), InstID, Vals)) // ptr
2946         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
2947     }
2948     Vals.push_back(VE.getTypeID(I.getType()));
2949     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
2950     Vals.push_back(cast<LoadInst>(I).isVolatile());
2951     if (cast<LoadInst>(I).isAtomic()) {
2952       Vals.push_back(getEncodedOrdering(cast<LoadInst>(I).getOrdering()));
2953       Vals.push_back(getEncodedSyncScopeID(cast<LoadInst>(I).getSyncScopeID()));
2954     }
2955     break;
2956   case Instruction::Store:
2957     if (cast<StoreInst>(I).isAtomic())
2958       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
2959     else
2960       Code = bitc::FUNC_CODE_INST_STORE;
2961     pushValueAndType(I.getOperand(1), InstID, Vals); // ptrty + ptr
2962     pushValueAndType(I.getOperand(0), InstID, Vals); // valty + val
2963     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
2964     Vals.push_back(cast<StoreInst>(I).isVolatile());
2965     if (cast<StoreInst>(I).isAtomic()) {
2966       Vals.push_back(getEncodedOrdering(cast<StoreInst>(I).getOrdering()));
2967       Vals.push_back(
2968           getEncodedSyncScopeID(cast<StoreInst>(I).getSyncScopeID()));
2969     }
2970     break;
2971   case Instruction::AtomicCmpXchg:
2972     Code = bitc::FUNC_CODE_INST_CMPXCHG;
2973     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
2974     pushValueAndType(I.getOperand(1), InstID, Vals); // cmp.
2975     pushValue(I.getOperand(2), InstID, Vals);        // newval.
2976     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
2977     Vals.push_back(
2978         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
2979     Vals.push_back(
2980         getEncodedSyncScopeID(cast<AtomicCmpXchgInst>(I).getSyncScopeID()));
2981     Vals.push_back(
2982         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
2983     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
2984     break;
2985   case Instruction::AtomicRMW:
2986     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
2987     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
2988     pushValue(I.getOperand(1), InstID, Vals);        // val.
2989     Vals.push_back(
2990         getEncodedRMWOperation(cast<AtomicRMWInst>(I).getOperation()));
2991     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
2992     Vals.push_back(getEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
2993     Vals.push_back(
2994         getEncodedSyncScopeID(cast<AtomicRMWInst>(I).getSyncScopeID()));
2995     break;
2996   case Instruction::Fence:
2997     Code = bitc::FUNC_CODE_INST_FENCE;
2998     Vals.push_back(getEncodedOrdering(cast<FenceInst>(I).getOrdering()));
2999     Vals.push_back(getEncodedSyncScopeID(cast<FenceInst>(I).getSyncScopeID()));
3000     break;
3001   case Instruction::Call: {
3002     const CallInst &CI = cast<CallInst>(I);
3003     FunctionType *FTy = CI.getFunctionType();
3004 
3005     if (CI.hasOperandBundles())
3006       writeOperandBundles(&CI, InstID);
3007 
3008     Code = bitc::FUNC_CODE_INST_CALL;
3009 
3010     Vals.push_back(VE.getAttributeListID(CI.getAttributes()));
3011 
3012     unsigned Flags = getOptimizationFlags(&I);
3013     Vals.push_back(CI.getCallingConv() << bitc::CALL_CCONV |
3014                    unsigned(CI.isTailCall()) << bitc::CALL_TAIL |
3015                    unsigned(CI.isMustTailCall()) << bitc::CALL_MUSTTAIL |
3016                    1 << bitc::CALL_EXPLICIT_TYPE |
3017                    unsigned(CI.isNoTailCall()) << bitc::CALL_NOTAIL |
3018                    unsigned(Flags != 0) << bitc::CALL_FMF);
3019     if (Flags != 0)
3020       Vals.push_back(Flags);
3021 
3022     Vals.push_back(VE.getTypeID(FTy));
3023     pushValueAndType(CI.getCalledValue(), InstID, Vals); // Callee
3024 
3025     // Emit value #'s for the fixed parameters.
3026     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
3027       // Check for labels (can happen with asm labels).
3028       if (FTy->getParamType(i)->isLabelTy())
3029         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
3030       else
3031         pushValue(CI.getArgOperand(i), InstID, Vals); // fixed param.
3032     }
3033 
3034     // Emit type/value pairs for varargs params.
3035     if (FTy->isVarArg()) {
3036       for (unsigned i = FTy->getNumParams(), e = CI.getNumArgOperands();
3037            i != e; ++i)
3038         pushValueAndType(CI.getArgOperand(i), InstID, Vals); // varargs
3039     }
3040     break;
3041   }
3042   case Instruction::VAArg:
3043     Code = bitc::FUNC_CODE_INST_VAARG;
3044     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
3045     pushValue(I.getOperand(0), InstID, Vals);                   // valist.
3046     Vals.push_back(VE.getTypeID(I.getType())); // restype.
3047     break;
3048   case Instruction::Freeze:
3049     Code = bitc::FUNC_CODE_INST_FREEZE;
3050     pushValueAndType(I.getOperand(0), InstID, Vals);
3051     break;
3052   }
3053 
3054   Stream.EmitRecord(Code, Vals, AbbrevToUse);
3055   Vals.clear();
3056 }
3057 
3058 /// Write a GlobalValue VST to the module. The purpose of this data structure is
3059 /// to allow clients to efficiently find the function body.
3060 void ModuleBitcodeWriter::writeGlobalValueSymbolTable(
3061   DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3062   // Get the offset of the VST we are writing, and backpatch it into
3063   // the VST forward declaration record.
3064   uint64_t VSTOffset = Stream.GetCurrentBitNo();
3065   // The BitcodeStartBit was the stream offset of the identification block.
3066   VSTOffset -= bitcodeStartBit();
3067   assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
3068   // Note that we add 1 here because the offset is relative to one word
3069   // before the start of the identification block, which was historically
3070   // always the start of the regular bitcode header.
3071   Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32 + 1);
3072 
3073   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3074 
3075   auto Abbv = std::make_shared<BitCodeAbbrev>();
3076   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
3077   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
3078   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
3079   unsigned FnEntryAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3080 
3081   for (const Function &F : M) {
3082     uint64_t Record[2];
3083 
3084     if (F.isDeclaration())
3085       continue;
3086 
3087     Record[0] = VE.getValueID(&F);
3088 
3089     // Save the word offset of the function (from the start of the
3090     // actual bitcode written to the stream).
3091     uint64_t BitcodeIndex = FunctionToBitcodeIndex[&F] - bitcodeStartBit();
3092     assert((BitcodeIndex & 31) == 0 && "function block not 32-bit aligned");
3093     // Note that we add 1 here because the offset is relative to one word
3094     // before the start of the identification block, which was historically
3095     // always the start of the regular bitcode header.
3096     Record[1] = BitcodeIndex / 32 + 1;
3097 
3098     Stream.EmitRecord(bitc::VST_CODE_FNENTRY, Record, FnEntryAbbrev);
3099   }
3100 
3101   Stream.ExitBlock();
3102 }
3103 
3104 /// Emit names for arguments, instructions and basic blocks in a function.
3105 void ModuleBitcodeWriter::writeFunctionLevelValueSymbolTable(
3106     const ValueSymbolTable &VST) {
3107   if (VST.empty())
3108     return;
3109 
3110   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3111 
3112   // FIXME: Set up the abbrev, we know how many values there are!
3113   // FIXME: We know if the type names can use 7-bit ascii.
3114   SmallVector<uint64_t, 64> NameVals;
3115 
3116   for (const ValueName &Name : VST) {
3117     // Figure out the encoding to use for the name.
3118     StringEncoding Bits = getStringEncoding(Name.getKey());
3119 
3120     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
3121     NameVals.push_back(VE.getValueID(Name.getValue()));
3122 
3123     // VST_CODE_ENTRY:   [valueid, namechar x N]
3124     // VST_CODE_BBENTRY: [bbid, namechar x N]
3125     unsigned Code;
3126     if (isa<BasicBlock>(Name.getValue())) {
3127       Code = bitc::VST_CODE_BBENTRY;
3128       if (Bits == SE_Char6)
3129         AbbrevToUse = VST_BBENTRY_6_ABBREV;
3130     } else {
3131       Code = bitc::VST_CODE_ENTRY;
3132       if (Bits == SE_Char6)
3133         AbbrevToUse = VST_ENTRY_6_ABBREV;
3134       else if (Bits == SE_Fixed7)
3135         AbbrevToUse = VST_ENTRY_7_ABBREV;
3136     }
3137 
3138     for (const auto P : Name.getKey())
3139       NameVals.push_back((unsigned char)P);
3140 
3141     // Emit the finished record.
3142     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
3143     NameVals.clear();
3144   }
3145 
3146   Stream.ExitBlock();
3147 }
3148 
3149 void ModuleBitcodeWriter::writeUseList(UseListOrder &&Order) {
3150   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
3151   unsigned Code;
3152   if (isa<BasicBlock>(Order.V))
3153     Code = bitc::USELIST_CODE_BB;
3154   else
3155     Code = bitc::USELIST_CODE_DEFAULT;
3156 
3157   SmallVector<uint64_t, 64> Record(Order.Shuffle.begin(), Order.Shuffle.end());
3158   Record.push_back(VE.getValueID(Order.V));
3159   Stream.EmitRecord(Code, Record);
3160 }
3161 
3162 void ModuleBitcodeWriter::writeUseListBlock(const Function *F) {
3163   assert(VE.shouldPreserveUseListOrder() &&
3164          "Expected to be preserving use-list order");
3165 
3166   auto hasMore = [&]() {
3167     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
3168   };
3169   if (!hasMore())
3170     // Nothing to do.
3171     return;
3172 
3173   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
3174   while (hasMore()) {
3175     writeUseList(std::move(VE.UseListOrders.back()));
3176     VE.UseListOrders.pop_back();
3177   }
3178   Stream.ExitBlock();
3179 }
3180 
3181 /// Emit a function body to the module stream.
3182 void ModuleBitcodeWriter::writeFunction(
3183     const Function &F,
3184     DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3185   // Save the bitcode index of the start of this function block for recording
3186   // in the VST.
3187   FunctionToBitcodeIndex[&F] = Stream.GetCurrentBitNo();
3188 
3189   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
3190   VE.incorporateFunction(F);
3191 
3192   SmallVector<unsigned, 64> Vals;
3193 
3194   // Emit the number of basic blocks, so the reader can create them ahead of
3195   // time.
3196   Vals.push_back(VE.getBasicBlocks().size());
3197   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
3198   Vals.clear();
3199 
3200   // If there are function-local constants, emit them now.
3201   unsigned CstStart, CstEnd;
3202   VE.getFunctionConstantRange(CstStart, CstEnd);
3203   writeConstants(CstStart, CstEnd, false);
3204 
3205   // If there is function-local metadata, emit it now.
3206   writeFunctionMetadata(F);
3207 
3208   // Keep a running idea of what the instruction ID is.
3209   unsigned InstID = CstEnd;
3210 
3211   bool NeedsMetadataAttachment = F.hasMetadata();
3212 
3213   DILocation *LastDL = nullptr;
3214   // Finally, emit all the instructions, in order.
3215   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
3216     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
3217          I != E; ++I) {
3218       writeInstruction(*I, InstID, Vals);
3219 
3220       if (!I->getType()->isVoidTy())
3221         ++InstID;
3222 
3223       // If the instruction has metadata, write a metadata attachment later.
3224       NeedsMetadataAttachment |= I->hasMetadataOtherThanDebugLoc();
3225 
3226       // If the instruction has a debug location, emit it.
3227       DILocation *DL = I->getDebugLoc();
3228       if (!DL)
3229         continue;
3230 
3231       if (DL == LastDL) {
3232         // Just repeat the same debug loc as last time.
3233         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
3234         continue;
3235       }
3236 
3237       Vals.push_back(DL->getLine());
3238       Vals.push_back(DL->getColumn());
3239       Vals.push_back(VE.getMetadataOrNullID(DL->getScope()));
3240       Vals.push_back(VE.getMetadataOrNullID(DL->getInlinedAt()));
3241       Vals.push_back(DL->isImplicitCode());
3242       Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
3243       Vals.clear();
3244 
3245       LastDL = DL;
3246     }
3247 
3248   // Emit names for all the instructions etc.
3249   if (auto *Symtab = F.getValueSymbolTable())
3250     writeFunctionLevelValueSymbolTable(*Symtab);
3251 
3252   if (NeedsMetadataAttachment)
3253     writeFunctionMetadataAttachment(F);
3254   if (VE.shouldPreserveUseListOrder())
3255     writeUseListBlock(&F);
3256   VE.purgeFunction();
3257   Stream.ExitBlock();
3258 }
3259 
3260 // Emit blockinfo, which defines the standard abbreviations etc.
3261 void ModuleBitcodeWriter::writeBlockInfo() {
3262   // We only want to emit block info records for blocks that have multiple
3263   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
3264   // Other blocks can define their abbrevs inline.
3265   Stream.EnterBlockInfoBlock();
3266 
3267   { // 8-bit fixed-width VST_CODE_ENTRY/VST_CODE_BBENTRY strings.
3268     auto Abbv = std::make_shared<BitCodeAbbrev>();
3269     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
3270     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3271     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3272     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3273     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3274         VST_ENTRY_8_ABBREV)
3275       llvm_unreachable("Unexpected abbrev ordering!");
3276   }
3277 
3278   { // 7-bit fixed width VST_CODE_ENTRY strings.
3279     auto Abbv = std::make_shared<BitCodeAbbrev>();
3280     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3281     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3282     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3283     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3284     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3285         VST_ENTRY_7_ABBREV)
3286       llvm_unreachable("Unexpected abbrev ordering!");
3287   }
3288   { // 6-bit char6 VST_CODE_ENTRY strings.
3289     auto Abbv = std::make_shared<BitCodeAbbrev>();
3290     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3291     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3292     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3293     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3294     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3295         VST_ENTRY_6_ABBREV)
3296       llvm_unreachable("Unexpected abbrev ordering!");
3297   }
3298   { // 6-bit char6 VST_CODE_BBENTRY strings.
3299     auto Abbv = std::make_shared<BitCodeAbbrev>();
3300     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
3301     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3302     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3303     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3304     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3305         VST_BBENTRY_6_ABBREV)
3306       llvm_unreachable("Unexpected abbrev ordering!");
3307   }
3308 
3309   { // SETTYPE abbrev for CONSTANTS_BLOCK.
3310     auto Abbv = std::make_shared<BitCodeAbbrev>();
3311     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
3312     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
3313                               VE.computeBitsRequiredForTypeIndicies()));
3314     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3315         CONSTANTS_SETTYPE_ABBREV)
3316       llvm_unreachable("Unexpected abbrev ordering!");
3317   }
3318 
3319   { // INTEGER abbrev for CONSTANTS_BLOCK.
3320     auto Abbv = std::make_shared<BitCodeAbbrev>();
3321     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
3322     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3323     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3324         CONSTANTS_INTEGER_ABBREV)
3325       llvm_unreachable("Unexpected abbrev ordering!");
3326   }
3327 
3328   { // CE_CAST abbrev for CONSTANTS_BLOCK.
3329     auto Abbv = std::make_shared<BitCodeAbbrev>();
3330     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
3331     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
3332     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
3333                               VE.computeBitsRequiredForTypeIndicies()));
3334     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
3335 
3336     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3337         CONSTANTS_CE_CAST_Abbrev)
3338       llvm_unreachable("Unexpected abbrev ordering!");
3339   }
3340   { // NULL abbrev for CONSTANTS_BLOCK.
3341     auto Abbv = std::make_shared<BitCodeAbbrev>();
3342     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
3343     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3344         CONSTANTS_NULL_Abbrev)
3345       llvm_unreachable("Unexpected abbrev ordering!");
3346   }
3347 
3348   // FIXME: This should only use space for first class types!
3349 
3350   { // INST_LOAD abbrev for FUNCTION_BLOCK.
3351     auto Abbv = std::make_shared<BitCodeAbbrev>();
3352     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
3353     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
3354     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
3355                               VE.computeBitsRequiredForTypeIndicies()));
3356     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
3357     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
3358     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3359         FUNCTION_INST_LOAD_ABBREV)
3360       llvm_unreachable("Unexpected abbrev ordering!");
3361   }
3362   { // INST_UNOP abbrev for FUNCTION_BLOCK.
3363     auto Abbv = std::make_shared<BitCodeAbbrev>();
3364     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3365     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3366     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3367     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3368         FUNCTION_INST_UNOP_ABBREV)
3369       llvm_unreachable("Unexpected abbrev ordering!");
3370   }
3371   { // INST_UNOP_FLAGS abbrev for FUNCTION_BLOCK.
3372     auto Abbv = std::make_shared<BitCodeAbbrev>();
3373     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3374     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3375     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3376     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3377     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3378         FUNCTION_INST_UNOP_FLAGS_ABBREV)
3379       llvm_unreachable("Unexpected abbrev ordering!");
3380   }
3381   { // INST_BINOP abbrev for FUNCTION_BLOCK.
3382     auto Abbv = std::make_shared<BitCodeAbbrev>();
3383     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3384     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3385     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3386     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3387     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3388         FUNCTION_INST_BINOP_ABBREV)
3389       llvm_unreachable("Unexpected abbrev ordering!");
3390   }
3391   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
3392     auto Abbv = std::make_shared<BitCodeAbbrev>();
3393     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3394     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3395     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3396     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3397     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3398     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3399         FUNCTION_INST_BINOP_FLAGS_ABBREV)
3400       llvm_unreachable("Unexpected abbrev ordering!");
3401   }
3402   { // INST_CAST abbrev for FUNCTION_BLOCK.
3403     auto Abbv = std::make_shared<BitCodeAbbrev>();
3404     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
3405     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
3406     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
3407                               VE.computeBitsRequiredForTypeIndicies()));
3408     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
3409     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3410         FUNCTION_INST_CAST_ABBREV)
3411       llvm_unreachable("Unexpected abbrev ordering!");
3412   }
3413 
3414   { // INST_RET abbrev for FUNCTION_BLOCK.
3415     auto Abbv = std::make_shared<BitCodeAbbrev>();
3416     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3417     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3418         FUNCTION_INST_RET_VOID_ABBREV)
3419       llvm_unreachable("Unexpected abbrev ordering!");
3420   }
3421   { // INST_RET abbrev for FUNCTION_BLOCK.
3422     auto Abbv = std::make_shared<BitCodeAbbrev>();
3423     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3424     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
3425     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3426         FUNCTION_INST_RET_VAL_ABBREV)
3427       llvm_unreachable("Unexpected abbrev ordering!");
3428   }
3429   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
3430     auto Abbv = std::make_shared<BitCodeAbbrev>();
3431     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
3432     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3433         FUNCTION_INST_UNREACHABLE_ABBREV)
3434       llvm_unreachable("Unexpected abbrev ordering!");
3435   }
3436   {
3437     auto Abbv = std::make_shared<BitCodeAbbrev>();
3438     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_GEP));
3439     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
3440     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, // dest ty
3441                               Log2_32_Ceil(VE.getTypes().size() + 1)));
3442     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3443     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
3444     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3445         FUNCTION_INST_GEP_ABBREV)
3446       llvm_unreachable("Unexpected abbrev ordering!");
3447   }
3448 
3449   Stream.ExitBlock();
3450 }
3451 
3452 /// Write the module path strings, currently only used when generating
3453 /// a combined index file.
3454 void IndexBitcodeWriter::writeModStrings() {
3455   Stream.EnterSubblock(bitc::MODULE_STRTAB_BLOCK_ID, 3);
3456 
3457   // TODO: See which abbrev sizes we actually need to emit
3458 
3459   // 8-bit fixed-width MST_ENTRY strings.
3460   auto Abbv = std::make_shared<BitCodeAbbrev>();
3461   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3462   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3463   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3464   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3465   unsigned Abbrev8Bit = Stream.EmitAbbrev(std::move(Abbv));
3466 
3467   // 7-bit fixed width MST_ENTRY strings.
3468   Abbv = std::make_shared<BitCodeAbbrev>();
3469   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3470   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3471   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3472   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3473   unsigned Abbrev7Bit = Stream.EmitAbbrev(std::move(Abbv));
3474 
3475   // 6-bit char6 MST_ENTRY strings.
3476   Abbv = std::make_shared<BitCodeAbbrev>();
3477   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3478   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3479   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3480   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3481   unsigned Abbrev6Bit = Stream.EmitAbbrev(std::move(Abbv));
3482 
3483   // Module Hash, 160 bits SHA1. Optionally, emitted after each MST_CODE_ENTRY.
3484   Abbv = std::make_shared<BitCodeAbbrev>();
3485   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_HASH));
3486   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3487   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3488   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3489   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3490   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3491   unsigned AbbrevHash = Stream.EmitAbbrev(std::move(Abbv));
3492 
3493   SmallVector<unsigned, 64> Vals;
3494   forEachModule(
3495       [&](const StringMapEntry<std::pair<uint64_t, ModuleHash>> &MPSE) {
3496         StringRef Key = MPSE.getKey();
3497         const auto &Value = MPSE.getValue();
3498         StringEncoding Bits = getStringEncoding(Key);
3499         unsigned AbbrevToUse = Abbrev8Bit;
3500         if (Bits == SE_Char6)
3501           AbbrevToUse = Abbrev6Bit;
3502         else if (Bits == SE_Fixed7)
3503           AbbrevToUse = Abbrev7Bit;
3504 
3505         Vals.push_back(Value.first);
3506         Vals.append(Key.begin(), Key.end());
3507 
3508         // Emit the finished record.
3509         Stream.EmitRecord(bitc::MST_CODE_ENTRY, Vals, AbbrevToUse);
3510 
3511         // Emit an optional hash for the module now
3512         const auto &Hash = Value.second;
3513         if (llvm::any_of(Hash, [](uint32_t H) { return H; })) {
3514           Vals.assign(Hash.begin(), Hash.end());
3515           // Emit the hash record.
3516           Stream.EmitRecord(bitc::MST_CODE_HASH, Vals, AbbrevHash);
3517         }
3518 
3519         Vals.clear();
3520       });
3521   Stream.ExitBlock();
3522 }
3523 
3524 /// Write the function type metadata related records that need to appear before
3525 /// a function summary entry (whether per-module or combined).
3526 static void writeFunctionTypeMetadataRecords(BitstreamWriter &Stream,
3527                                              FunctionSummary *FS) {
3528   if (!FS->type_tests().empty())
3529     Stream.EmitRecord(bitc::FS_TYPE_TESTS, FS->type_tests());
3530 
3531   SmallVector<uint64_t, 64> Record;
3532 
3533   auto WriteVFuncIdVec = [&](uint64_t Ty,
3534                              ArrayRef<FunctionSummary::VFuncId> VFs) {
3535     if (VFs.empty())
3536       return;
3537     Record.clear();
3538     for (auto &VF : VFs) {
3539       Record.push_back(VF.GUID);
3540       Record.push_back(VF.Offset);
3541     }
3542     Stream.EmitRecord(Ty, Record);
3543   };
3544 
3545   WriteVFuncIdVec(bitc::FS_TYPE_TEST_ASSUME_VCALLS,
3546                   FS->type_test_assume_vcalls());
3547   WriteVFuncIdVec(bitc::FS_TYPE_CHECKED_LOAD_VCALLS,
3548                   FS->type_checked_load_vcalls());
3549 
3550   auto WriteConstVCallVec = [&](uint64_t Ty,
3551                                 ArrayRef<FunctionSummary::ConstVCall> VCs) {
3552     for (auto &VC : VCs) {
3553       Record.clear();
3554       Record.push_back(VC.VFunc.GUID);
3555       Record.push_back(VC.VFunc.Offset);
3556       Record.insert(Record.end(), VC.Args.begin(), VC.Args.end());
3557       Stream.EmitRecord(Ty, Record);
3558     }
3559   };
3560 
3561   WriteConstVCallVec(bitc::FS_TYPE_TEST_ASSUME_CONST_VCALL,
3562                      FS->type_test_assume_const_vcalls());
3563   WriteConstVCallVec(bitc::FS_TYPE_CHECKED_LOAD_CONST_VCALL,
3564                      FS->type_checked_load_const_vcalls());
3565 }
3566 
3567 /// Collect type IDs from type tests used by function.
3568 static void
3569 getReferencedTypeIds(FunctionSummary *FS,
3570                      std::set<GlobalValue::GUID> &ReferencedTypeIds) {
3571   if (!FS->type_tests().empty())
3572     for (auto &TT : FS->type_tests())
3573       ReferencedTypeIds.insert(TT);
3574 
3575   auto GetReferencedTypesFromVFuncIdVec =
3576       [&](ArrayRef<FunctionSummary::VFuncId> VFs) {
3577         for (auto &VF : VFs)
3578           ReferencedTypeIds.insert(VF.GUID);
3579       };
3580 
3581   GetReferencedTypesFromVFuncIdVec(FS->type_test_assume_vcalls());
3582   GetReferencedTypesFromVFuncIdVec(FS->type_checked_load_vcalls());
3583 
3584   auto GetReferencedTypesFromConstVCallVec =
3585       [&](ArrayRef<FunctionSummary::ConstVCall> VCs) {
3586         for (auto &VC : VCs)
3587           ReferencedTypeIds.insert(VC.VFunc.GUID);
3588       };
3589 
3590   GetReferencedTypesFromConstVCallVec(FS->type_test_assume_const_vcalls());
3591   GetReferencedTypesFromConstVCallVec(FS->type_checked_load_const_vcalls());
3592 }
3593 
3594 static void writeWholeProgramDevirtResolutionByArg(
3595     SmallVector<uint64_t, 64> &NameVals, const std::vector<uint64_t> &args,
3596     const WholeProgramDevirtResolution::ByArg &ByArg) {
3597   NameVals.push_back(args.size());
3598   NameVals.insert(NameVals.end(), args.begin(), args.end());
3599 
3600   NameVals.push_back(ByArg.TheKind);
3601   NameVals.push_back(ByArg.Info);
3602   NameVals.push_back(ByArg.Byte);
3603   NameVals.push_back(ByArg.Bit);
3604 }
3605 
3606 static void writeWholeProgramDevirtResolution(
3607     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3608     uint64_t Id, const WholeProgramDevirtResolution &Wpd) {
3609   NameVals.push_back(Id);
3610 
3611   NameVals.push_back(Wpd.TheKind);
3612   NameVals.push_back(StrtabBuilder.add(Wpd.SingleImplName));
3613   NameVals.push_back(Wpd.SingleImplName.size());
3614 
3615   NameVals.push_back(Wpd.ResByArg.size());
3616   for (auto &A : Wpd.ResByArg)
3617     writeWholeProgramDevirtResolutionByArg(NameVals, A.first, A.second);
3618 }
3619 
3620 static void writeTypeIdSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
3621                                      StringTableBuilder &StrtabBuilder,
3622                                      const std::string &Id,
3623                                      const TypeIdSummary &Summary) {
3624   NameVals.push_back(StrtabBuilder.add(Id));
3625   NameVals.push_back(Id.size());
3626 
3627   NameVals.push_back(Summary.TTRes.TheKind);
3628   NameVals.push_back(Summary.TTRes.SizeM1BitWidth);
3629   NameVals.push_back(Summary.TTRes.AlignLog2);
3630   NameVals.push_back(Summary.TTRes.SizeM1);
3631   NameVals.push_back(Summary.TTRes.BitMask);
3632   NameVals.push_back(Summary.TTRes.InlineBits);
3633 
3634   for (auto &W : Summary.WPDRes)
3635     writeWholeProgramDevirtResolution(NameVals, StrtabBuilder, W.first,
3636                                       W.second);
3637 }
3638 
3639 static void writeTypeIdCompatibleVtableSummaryRecord(
3640     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3641     const std::string &Id, const TypeIdCompatibleVtableInfo &Summary,
3642     ValueEnumerator &VE) {
3643   NameVals.push_back(StrtabBuilder.add(Id));
3644   NameVals.push_back(Id.size());
3645 
3646   for (auto &P : Summary) {
3647     NameVals.push_back(P.AddressPointOffset);
3648     NameVals.push_back(VE.getValueID(P.VTableVI.getValue()));
3649   }
3650 }
3651 
3652 // Helper to emit a single function summary record.
3653 void ModuleBitcodeWriterBase::writePerModuleFunctionSummaryRecord(
3654     SmallVector<uint64_t, 64> &NameVals, GlobalValueSummary *Summary,
3655     unsigned ValueID, unsigned FSCallsAbbrev, unsigned FSCallsProfileAbbrev,
3656     const Function &F) {
3657   NameVals.push_back(ValueID);
3658 
3659   FunctionSummary *FS = cast<FunctionSummary>(Summary);
3660   writeFunctionTypeMetadataRecords(Stream, FS);
3661 
3662   auto SpecialRefCnts = FS->specialRefCounts();
3663   NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
3664   NameVals.push_back(FS->instCount());
3665   NameVals.push_back(getEncodedFFlags(FS->fflags()));
3666   NameVals.push_back(FS->refs().size());
3667   NameVals.push_back(SpecialRefCnts.first);  // rorefcnt
3668   NameVals.push_back(SpecialRefCnts.second); // worefcnt
3669 
3670   for (auto &RI : FS->refs())
3671     NameVals.push_back(VE.getValueID(RI.getValue()));
3672 
3673   bool HasProfileData =
3674       F.hasProfileData() || ForceSummaryEdgesCold != FunctionSummary::FSHT_None;
3675   for (auto &ECI : FS->calls()) {
3676     NameVals.push_back(getValueId(ECI.first));
3677     if (HasProfileData)
3678       NameVals.push_back(static_cast<uint8_t>(ECI.second.Hotness));
3679     else if (WriteRelBFToSummary)
3680       NameVals.push_back(ECI.second.RelBlockFreq);
3681   }
3682 
3683   unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
3684   unsigned Code =
3685       (HasProfileData ? bitc::FS_PERMODULE_PROFILE
3686                       : (WriteRelBFToSummary ? bitc::FS_PERMODULE_RELBF
3687                                              : bitc::FS_PERMODULE));
3688 
3689   // Emit the finished record.
3690   Stream.EmitRecord(Code, NameVals, FSAbbrev);
3691   NameVals.clear();
3692 }
3693 
3694 // Collect the global value references in the given variable's initializer,
3695 // and emit them in a summary record.
3696 void ModuleBitcodeWriterBase::writeModuleLevelReferences(
3697     const GlobalVariable &V, SmallVector<uint64_t, 64> &NameVals,
3698     unsigned FSModRefsAbbrev, unsigned FSModVTableRefsAbbrev) {
3699   auto VI = Index->getValueInfo(V.getGUID());
3700   if (!VI || VI.getSummaryList().empty()) {
3701     // Only declarations should not have a summary (a declaration might however
3702     // have a summary if the def was in module level asm).
3703     assert(V.isDeclaration());
3704     return;
3705   }
3706   auto *Summary = VI.getSummaryList()[0].get();
3707   NameVals.push_back(VE.getValueID(&V));
3708   GlobalVarSummary *VS = cast<GlobalVarSummary>(Summary);
3709   NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
3710   NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
3711 
3712   auto VTableFuncs = VS->vTableFuncs();
3713   if (!VTableFuncs.empty())
3714     NameVals.push_back(VS->refs().size());
3715 
3716   unsigned SizeBeforeRefs = NameVals.size();
3717   for (auto &RI : VS->refs())
3718     NameVals.push_back(VE.getValueID(RI.getValue()));
3719   // Sort the refs for determinism output, the vector returned by FS->refs() has
3720   // been initialized from a DenseSet.
3721   llvm::sort(NameVals.begin() + SizeBeforeRefs, NameVals.end());
3722 
3723   if (VTableFuncs.empty())
3724     Stream.EmitRecord(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS, NameVals,
3725                       FSModRefsAbbrev);
3726   else {
3727     // VTableFuncs pairs should already be sorted by offset.
3728     for (auto &P : VTableFuncs) {
3729       NameVals.push_back(VE.getValueID(P.FuncVI.getValue()));
3730       NameVals.push_back(P.VTableOffset);
3731     }
3732 
3733     Stream.EmitRecord(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS, NameVals,
3734                       FSModVTableRefsAbbrev);
3735   }
3736   NameVals.clear();
3737 }
3738 
3739 /// Emit the per-module summary section alongside the rest of
3740 /// the module's bitcode.
3741 void ModuleBitcodeWriterBase::writePerModuleGlobalValueSummary() {
3742   // By default we compile with ThinLTO if the module has a summary, but the
3743   // client can request full LTO with a module flag.
3744   bool IsThinLTO = true;
3745   if (auto *MD =
3746           mdconst::extract_or_null<ConstantInt>(M.getModuleFlag("ThinLTO")))
3747     IsThinLTO = MD->getZExtValue();
3748   Stream.EnterSubblock(IsThinLTO ? bitc::GLOBALVAL_SUMMARY_BLOCK_ID
3749                                  : bitc::FULL_LTO_GLOBALVAL_SUMMARY_BLOCK_ID,
3750                        4);
3751 
3752   Stream.EmitRecord(
3753       bitc::FS_VERSION,
3754       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
3755 
3756   // Write the index flags.
3757   uint64_t Flags = 0;
3758   // Bits 1-3 are set only in the combined index, skip them.
3759   if (Index->enableSplitLTOUnit())
3760     Flags |= 0x8;
3761   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Flags});
3762 
3763   if (Index->begin() == Index->end()) {
3764     Stream.ExitBlock();
3765     return;
3766   }
3767 
3768   for (const auto &GVI : valueIds()) {
3769     Stream.EmitRecord(bitc::FS_VALUE_GUID,
3770                       ArrayRef<uint64_t>{GVI.second, GVI.first});
3771   }
3772 
3773   // Abbrev for FS_PERMODULE_PROFILE.
3774   auto Abbv = std::make_shared<BitCodeAbbrev>();
3775   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_PROFILE));
3776   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3777   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3778   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3779   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3780   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3781   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
3782   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
3783   // numrefs x valueid, n x (valueid, hotness)
3784   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3785   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3786   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3787 
3788   // Abbrev for FS_PERMODULE or FS_PERMODULE_RELBF.
3789   Abbv = std::make_shared<BitCodeAbbrev>();
3790   if (WriteRelBFToSummary)
3791     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_RELBF));
3792   else
3793     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE));
3794   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3795   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3796   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3797   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3798   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3799   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
3800   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
3801   // numrefs x valueid, n x (valueid [, rel_block_freq])
3802   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3803   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3804   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3805 
3806   // Abbrev for FS_PERMODULE_GLOBALVAR_INIT_REFS.
3807   Abbv = std::make_shared<BitCodeAbbrev>();
3808   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS));
3809   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
3810   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
3811   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));  // valueids
3812   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3813   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3814 
3815   // Abbrev for FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS.
3816   Abbv = std::make_shared<BitCodeAbbrev>();
3817   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS));
3818   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
3819   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
3820   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numrefs
3821   // numrefs x valueid, n x (valueid , offset)
3822   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3823   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3824   unsigned FSModVTableRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3825 
3826   // Abbrev for FS_ALIAS.
3827   Abbv = std::make_shared<BitCodeAbbrev>();
3828   Abbv->Add(BitCodeAbbrevOp(bitc::FS_ALIAS));
3829   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3830   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3831   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3832   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3833 
3834   // Abbrev for FS_TYPE_ID_METADATA
3835   Abbv = std::make_shared<BitCodeAbbrev>();
3836   Abbv->Add(BitCodeAbbrevOp(bitc::FS_TYPE_ID_METADATA));
3837   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid strtab index
3838   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid length
3839   // n x (valueid , offset)
3840   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3841   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3842   unsigned TypeIdCompatibleVtableAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3843 
3844   SmallVector<uint64_t, 64> NameVals;
3845   // Iterate over the list of functions instead of the Index to
3846   // ensure the ordering is stable.
3847   for (const Function &F : M) {
3848     // Summary emission does not support anonymous functions, they have to
3849     // renamed using the anonymous function renaming pass.
3850     if (!F.hasName())
3851       report_fatal_error("Unexpected anonymous function when writing summary");
3852 
3853     ValueInfo VI = Index->getValueInfo(F.getGUID());
3854     if (!VI || VI.getSummaryList().empty()) {
3855       // Only declarations should not have a summary (a declaration might
3856       // however have a summary if the def was in module level asm).
3857       assert(F.isDeclaration());
3858       continue;
3859     }
3860     auto *Summary = VI.getSummaryList()[0].get();
3861     writePerModuleFunctionSummaryRecord(NameVals, Summary, VE.getValueID(&F),
3862                                         FSCallsAbbrev, FSCallsProfileAbbrev, F);
3863   }
3864 
3865   // Capture references from GlobalVariable initializers, which are outside
3866   // of a function scope.
3867   for (const GlobalVariable &G : M.globals())
3868     writeModuleLevelReferences(G, NameVals, FSModRefsAbbrev,
3869                                FSModVTableRefsAbbrev);
3870 
3871   for (const GlobalAlias &A : M.aliases()) {
3872     auto *Aliasee = A.getBaseObject();
3873     if (!Aliasee->hasName())
3874       // Nameless function don't have an entry in the summary, skip it.
3875       continue;
3876     auto AliasId = VE.getValueID(&A);
3877     auto AliaseeId = VE.getValueID(Aliasee);
3878     NameVals.push_back(AliasId);
3879     auto *Summary = Index->getGlobalValueSummary(A);
3880     AliasSummary *AS = cast<AliasSummary>(Summary);
3881     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
3882     NameVals.push_back(AliaseeId);
3883     Stream.EmitRecord(bitc::FS_ALIAS, NameVals, FSAliasAbbrev);
3884     NameVals.clear();
3885   }
3886 
3887   for (auto &S : Index->typeIdCompatibleVtableMap()) {
3888     writeTypeIdCompatibleVtableSummaryRecord(NameVals, StrtabBuilder, S.first,
3889                                              S.second, VE);
3890     Stream.EmitRecord(bitc::FS_TYPE_ID_METADATA, NameVals,
3891                       TypeIdCompatibleVtableAbbrev);
3892     NameVals.clear();
3893   }
3894 
3895   Stream.ExitBlock();
3896 }
3897 
3898 /// Emit the combined summary section into the combined index file.
3899 void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
3900   Stream.EnterSubblock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID, 3);
3901   Stream.EmitRecord(
3902       bitc::FS_VERSION,
3903       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
3904 
3905   // Write the index flags.
3906   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Index.getFlags()});
3907 
3908   for (const auto &GVI : valueIds()) {
3909     Stream.EmitRecord(bitc::FS_VALUE_GUID,
3910                       ArrayRef<uint64_t>{GVI.second, GVI.first});
3911   }
3912 
3913   // Abbrev for FS_COMBINED.
3914   auto Abbv = std::make_shared<BitCodeAbbrev>();
3915   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED));
3916   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3917   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3918   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3919   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3920   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3921   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
3922   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3923   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
3924   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
3925   // numrefs x valueid, n x (valueid)
3926   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3927   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3928   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3929 
3930   // Abbrev for FS_COMBINED_PROFILE.
3931   Abbv = std::make_shared<BitCodeAbbrev>();
3932   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_PROFILE));
3933   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3934   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3935   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3936   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3937   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3938   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
3939   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3940   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
3941   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
3942   // numrefs x valueid, n x (valueid, hotness)
3943   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3944   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3945   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3946 
3947   // Abbrev for FS_COMBINED_GLOBALVAR_INIT_REFS.
3948   Abbv = std::make_shared<BitCodeAbbrev>();
3949   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS));
3950   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3951   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3952   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3953   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));    // valueids
3954   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3955   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3956 
3957   // Abbrev for FS_COMBINED_ALIAS.
3958   Abbv = std::make_shared<BitCodeAbbrev>();
3959   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_ALIAS));
3960   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3961   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3962   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3963   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3964   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3965 
3966   // The aliases are emitted as a post-pass, and will point to the value
3967   // id of the aliasee. Save them in a vector for post-processing.
3968   SmallVector<AliasSummary *, 64> Aliases;
3969 
3970   // Save the value id for each summary for alias emission.
3971   DenseMap<const GlobalValueSummary *, unsigned> SummaryToValueIdMap;
3972 
3973   SmallVector<uint64_t, 64> NameVals;
3974 
3975   // Set that will be populated during call to writeFunctionTypeMetadataRecords
3976   // with the type ids referenced by this index file.
3977   std::set<GlobalValue::GUID> ReferencedTypeIds;
3978 
3979   // For local linkage, we also emit the original name separately
3980   // immediately after the record.
3981   auto MaybeEmitOriginalName = [&](GlobalValueSummary &S) {
3982     if (!GlobalValue::isLocalLinkage(S.linkage()))
3983       return;
3984     NameVals.push_back(S.getOriginalName());
3985     Stream.EmitRecord(bitc::FS_COMBINED_ORIGINAL_NAME, NameVals);
3986     NameVals.clear();
3987   };
3988 
3989   std::set<GlobalValue::GUID> DefOrUseGUIDs;
3990   forEachSummary([&](GVInfo I, bool IsAliasee) {
3991     GlobalValueSummary *S = I.second;
3992     assert(S);
3993     DefOrUseGUIDs.insert(I.first);
3994     for (const ValueInfo &VI : S->refs())
3995       DefOrUseGUIDs.insert(VI.getGUID());
3996 
3997     auto ValueId = getValueId(I.first);
3998     assert(ValueId);
3999     SummaryToValueIdMap[S] = *ValueId;
4000 
4001     // If this is invoked for an aliasee, we want to record the above
4002     // mapping, but then not emit a summary entry (if the aliasee is
4003     // to be imported, we will invoke this separately with IsAliasee=false).
4004     if (IsAliasee)
4005       return;
4006 
4007     if (auto *AS = dyn_cast<AliasSummary>(S)) {
4008       // Will process aliases as a post-pass because the reader wants all
4009       // global to be loaded first.
4010       Aliases.push_back(AS);
4011       return;
4012     }
4013 
4014     if (auto *VS = dyn_cast<GlobalVarSummary>(S)) {
4015       NameVals.push_back(*ValueId);
4016       NameVals.push_back(Index.getModuleId(VS->modulePath()));
4017       NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
4018       NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
4019       for (auto &RI : VS->refs()) {
4020         auto RefValueId = getValueId(RI.getGUID());
4021         if (!RefValueId)
4022           continue;
4023         NameVals.push_back(*RefValueId);
4024       }
4025 
4026       // Emit the finished record.
4027       Stream.EmitRecord(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS, NameVals,
4028                         FSModRefsAbbrev);
4029       NameVals.clear();
4030       MaybeEmitOriginalName(*S);
4031       return;
4032     }
4033 
4034     auto *FS = cast<FunctionSummary>(S);
4035     writeFunctionTypeMetadataRecords(Stream, FS);
4036     getReferencedTypeIds(FS, ReferencedTypeIds);
4037 
4038     NameVals.push_back(*ValueId);
4039     NameVals.push_back(Index.getModuleId(FS->modulePath()));
4040     NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
4041     NameVals.push_back(FS->instCount());
4042     NameVals.push_back(getEncodedFFlags(FS->fflags()));
4043     NameVals.push_back(FS->entryCount());
4044 
4045     // Fill in below
4046     NameVals.push_back(0); // numrefs
4047     NameVals.push_back(0); // rorefcnt
4048     NameVals.push_back(0); // worefcnt
4049 
4050     unsigned Count = 0, RORefCnt = 0, WORefCnt = 0;
4051     for (auto &RI : FS->refs()) {
4052       auto RefValueId = getValueId(RI.getGUID());
4053       if (!RefValueId)
4054         continue;
4055       NameVals.push_back(*RefValueId);
4056       if (RI.isReadOnly())
4057         RORefCnt++;
4058       else if (RI.isWriteOnly())
4059         WORefCnt++;
4060       Count++;
4061     }
4062     NameVals[6] = Count;
4063     NameVals[7] = RORefCnt;
4064     NameVals[8] = WORefCnt;
4065 
4066     bool HasProfileData = false;
4067     for (auto &EI : FS->calls()) {
4068       HasProfileData |=
4069           EI.second.getHotness() != CalleeInfo::HotnessType::Unknown;
4070       if (HasProfileData)
4071         break;
4072     }
4073 
4074     for (auto &EI : FS->calls()) {
4075       // If this GUID doesn't have a value id, it doesn't have a function
4076       // summary and we don't need to record any calls to it.
4077       GlobalValue::GUID GUID = EI.first.getGUID();
4078       auto CallValueId = getValueId(GUID);
4079       if (!CallValueId) {
4080         // For SamplePGO, the indirect call targets for local functions will
4081         // have its original name annotated in profile. We try to find the
4082         // corresponding PGOFuncName as the GUID.
4083         GUID = Index.getGUIDFromOriginalID(GUID);
4084         if (GUID == 0)
4085           continue;
4086         CallValueId = getValueId(GUID);
4087         if (!CallValueId)
4088           continue;
4089         // The mapping from OriginalId to GUID may return a GUID
4090         // that corresponds to a static variable. Filter it out here.
4091         // This can happen when
4092         // 1) There is a call to a library function which does not have
4093         // a CallValidId;
4094         // 2) There is a static variable with the  OriginalGUID identical
4095         // to the GUID of the library function in 1);
4096         // When this happens, the logic for SamplePGO kicks in and
4097         // the static variable in 2) will be found, which needs to be
4098         // filtered out.
4099         auto *GVSum = Index.getGlobalValueSummary(GUID, false);
4100         if (GVSum &&
4101             GVSum->getSummaryKind() == GlobalValueSummary::GlobalVarKind)
4102           continue;
4103       }
4104       NameVals.push_back(*CallValueId);
4105       if (HasProfileData)
4106         NameVals.push_back(static_cast<uint8_t>(EI.second.Hotness));
4107     }
4108 
4109     unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
4110     unsigned Code =
4111         (HasProfileData ? bitc::FS_COMBINED_PROFILE : bitc::FS_COMBINED);
4112 
4113     // Emit the finished record.
4114     Stream.EmitRecord(Code, NameVals, FSAbbrev);
4115     NameVals.clear();
4116     MaybeEmitOriginalName(*S);
4117   });
4118 
4119   for (auto *AS : Aliases) {
4120     auto AliasValueId = SummaryToValueIdMap[AS];
4121     assert(AliasValueId);
4122     NameVals.push_back(AliasValueId);
4123     NameVals.push_back(Index.getModuleId(AS->modulePath()));
4124     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
4125     auto AliaseeValueId = SummaryToValueIdMap[&AS->getAliasee()];
4126     assert(AliaseeValueId);
4127     NameVals.push_back(AliaseeValueId);
4128 
4129     // Emit the finished record.
4130     Stream.EmitRecord(bitc::FS_COMBINED_ALIAS, NameVals, FSAliasAbbrev);
4131     NameVals.clear();
4132     MaybeEmitOriginalName(*AS);
4133 
4134     if (auto *FS = dyn_cast<FunctionSummary>(&AS->getAliasee()))
4135       getReferencedTypeIds(FS, ReferencedTypeIds);
4136   }
4137 
4138   if (!Index.cfiFunctionDefs().empty()) {
4139     for (auto &S : Index.cfiFunctionDefs()) {
4140       if (DefOrUseGUIDs.count(
4141               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4142         NameVals.push_back(StrtabBuilder.add(S));
4143         NameVals.push_back(S.size());
4144       }
4145     }
4146     if (!NameVals.empty()) {
4147       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DEFS, NameVals);
4148       NameVals.clear();
4149     }
4150   }
4151 
4152   if (!Index.cfiFunctionDecls().empty()) {
4153     for (auto &S : Index.cfiFunctionDecls()) {
4154       if (DefOrUseGUIDs.count(
4155               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4156         NameVals.push_back(StrtabBuilder.add(S));
4157         NameVals.push_back(S.size());
4158       }
4159     }
4160     if (!NameVals.empty()) {
4161       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DECLS, NameVals);
4162       NameVals.clear();
4163     }
4164   }
4165 
4166   // Walk the GUIDs that were referenced, and write the
4167   // corresponding type id records.
4168   for (auto &T : ReferencedTypeIds) {
4169     auto TidIter = Index.typeIds().equal_range(T);
4170     for (auto It = TidIter.first; It != TidIter.second; ++It) {
4171       writeTypeIdSummaryRecord(NameVals, StrtabBuilder, It->second.first,
4172                                It->second.second);
4173       Stream.EmitRecord(bitc::FS_TYPE_ID, NameVals);
4174       NameVals.clear();
4175     }
4176   }
4177 
4178   Stream.ExitBlock();
4179 }
4180 
4181 /// Create the "IDENTIFICATION_BLOCK_ID" containing a single string with the
4182 /// current llvm version, and a record for the epoch number.
4183 static void writeIdentificationBlock(BitstreamWriter &Stream) {
4184   Stream.EnterSubblock(bitc::IDENTIFICATION_BLOCK_ID, 5);
4185 
4186   // Write the "user readable" string identifying the bitcode producer
4187   auto Abbv = std::make_shared<BitCodeAbbrev>();
4188   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_STRING));
4189   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4190   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
4191   auto StringAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4192   writeStringRecord(Stream, bitc::IDENTIFICATION_CODE_STRING,
4193                     "LLVM" LLVM_VERSION_STRING, StringAbbrev);
4194 
4195   // Write the epoch version
4196   Abbv = std::make_shared<BitCodeAbbrev>();
4197   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_EPOCH));
4198   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
4199   auto EpochAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4200   constexpr std::array<unsigned, 1> Vals = {{bitc::BITCODE_CURRENT_EPOCH}};
4201   Stream.EmitRecord(bitc::IDENTIFICATION_CODE_EPOCH, Vals, EpochAbbrev);
4202   Stream.ExitBlock();
4203 }
4204 
4205 void ModuleBitcodeWriter::writeModuleHash(size_t BlockStartPos) {
4206   // Emit the module's hash.
4207   // MODULE_CODE_HASH: [5*i32]
4208   if (GenerateHash) {
4209     uint32_t Vals[5];
4210     Hasher.update(ArrayRef<uint8_t>((const uint8_t *)&(Buffer)[BlockStartPos],
4211                                     Buffer.size() - BlockStartPos));
4212     StringRef Hash = Hasher.result();
4213     for (int Pos = 0; Pos < 20; Pos += 4) {
4214       Vals[Pos / 4] = support::endian::read32be(Hash.data() + Pos);
4215     }
4216 
4217     // Emit the finished record.
4218     Stream.EmitRecord(bitc::MODULE_CODE_HASH, Vals);
4219 
4220     if (ModHash)
4221       // Save the written hash value.
4222       llvm::copy(Vals, std::begin(*ModHash));
4223   }
4224 }
4225 
4226 void ModuleBitcodeWriter::write() {
4227   writeIdentificationBlock(Stream);
4228 
4229   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4230   size_t BlockStartPos = Buffer.size();
4231 
4232   writeModuleVersion();
4233 
4234   // Emit blockinfo, which defines the standard abbreviations etc.
4235   writeBlockInfo();
4236 
4237   // Emit information describing all of the types in the module.
4238   writeTypeTable();
4239 
4240   // Emit information about attribute groups.
4241   writeAttributeGroupTable();
4242 
4243   // Emit information about parameter attributes.
4244   writeAttributeTable();
4245 
4246   writeComdats();
4247 
4248   // Emit top-level description of module, including target triple, inline asm,
4249   // descriptors for global variables, and function prototype info.
4250   writeModuleInfo();
4251 
4252   // Emit constants.
4253   writeModuleConstants();
4254 
4255   // Emit metadata kind names.
4256   writeModuleMetadataKinds();
4257 
4258   // Emit metadata.
4259   writeModuleMetadata();
4260 
4261   // Emit module-level use-lists.
4262   if (VE.shouldPreserveUseListOrder())
4263     writeUseListBlock(nullptr);
4264 
4265   writeOperandBundleTags();
4266   writeSyncScopeNames();
4267 
4268   // Emit function bodies.
4269   DenseMap<const Function *, uint64_t> FunctionToBitcodeIndex;
4270   for (Module::const_iterator F = M.begin(), E = M.end(); F != E; ++F)
4271     if (!F->isDeclaration())
4272       writeFunction(*F, FunctionToBitcodeIndex);
4273 
4274   // Need to write after the above call to WriteFunction which populates
4275   // the summary information in the index.
4276   if (Index)
4277     writePerModuleGlobalValueSummary();
4278 
4279   writeGlobalValueSymbolTable(FunctionToBitcodeIndex);
4280 
4281   writeModuleHash(BlockStartPos);
4282 
4283   Stream.ExitBlock();
4284 }
4285 
4286 static void writeInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
4287                                uint32_t &Position) {
4288   support::endian::write32le(&Buffer[Position], Value);
4289   Position += 4;
4290 }
4291 
4292 /// If generating a bc file on darwin, we have to emit a
4293 /// header and trailer to make it compatible with the system archiver.  To do
4294 /// this we emit the following header, and then emit a trailer that pads the
4295 /// file out to be a multiple of 16 bytes.
4296 ///
4297 /// struct bc_header {
4298 ///   uint32_t Magic;         // 0x0B17C0DE
4299 ///   uint32_t Version;       // Version, currently always 0.
4300 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
4301 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
4302 ///   uint32_t CPUType;       // CPU specifier.
4303 ///   ... potentially more later ...
4304 /// };
4305 static void emitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
4306                                          const Triple &TT) {
4307   unsigned CPUType = ~0U;
4308 
4309   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
4310   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
4311   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
4312   // specific constants here because they are implicitly part of the Darwin ABI.
4313   enum {
4314     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
4315     DARWIN_CPU_TYPE_X86        = 7,
4316     DARWIN_CPU_TYPE_ARM        = 12,
4317     DARWIN_CPU_TYPE_POWERPC    = 18
4318   };
4319 
4320   Triple::ArchType Arch = TT.getArch();
4321   if (Arch == Triple::x86_64)
4322     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
4323   else if (Arch == Triple::x86)
4324     CPUType = DARWIN_CPU_TYPE_X86;
4325   else if (Arch == Triple::ppc)
4326     CPUType = DARWIN_CPU_TYPE_POWERPC;
4327   else if (Arch == Triple::ppc64)
4328     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
4329   else if (Arch == Triple::arm || Arch == Triple::thumb)
4330     CPUType = DARWIN_CPU_TYPE_ARM;
4331 
4332   // Traditional Bitcode starts after header.
4333   assert(Buffer.size() >= BWH_HeaderSize &&
4334          "Expected header size to be reserved");
4335   unsigned BCOffset = BWH_HeaderSize;
4336   unsigned BCSize = Buffer.size() - BWH_HeaderSize;
4337 
4338   // Write the magic and version.
4339   unsigned Position = 0;
4340   writeInt32ToBuffer(0x0B17C0DE, Buffer, Position);
4341   writeInt32ToBuffer(0, Buffer, Position); // Version.
4342   writeInt32ToBuffer(BCOffset, Buffer, Position);
4343   writeInt32ToBuffer(BCSize, Buffer, Position);
4344   writeInt32ToBuffer(CPUType, Buffer, Position);
4345 
4346   // If the file is not a multiple of 16 bytes, insert dummy padding.
4347   while (Buffer.size() & 15)
4348     Buffer.push_back(0);
4349 }
4350 
4351 /// Helper to write the header common to all bitcode files.
4352 static void writeBitcodeHeader(BitstreamWriter &Stream) {
4353   // Emit the file header.
4354   Stream.Emit((unsigned)'B', 8);
4355   Stream.Emit((unsigned)'C', 8);
4356   Stream.Emit(0x0, 4);
4357   Stream.Emit(0xC, 4);
4358   Stream.Emit(0xE, 4);
4359   Stream.Emit(0xD, 4);
4360 }
4361 
4362 BitcodeWriter::BitcodeWriter(SmallVectorImpl<char> &Buffer)
4363     : Buffer(Buffer), Stream(new BitstreamWriter(Buffer)) {
4364   writeBitcodeHeader(*Stream);
4365 }
4366 
4367 BitcodeWriter::~BitcodeWriter() { assert(WroteStrtab); }
4368 
4369 void BitcodeWriter::writeBlob(unsigned Block, unsigned Record, StringRef Blob) {
4370   Stream->EnterSubblock(Block, 3);
4371 
4372   auto Abbv = std::make_shared<BitCodeAbbrev>();
4373   Abbv->Add(BitCodeAbbrevOp(Record));
4374   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
4375   auto AbbrevNo = Stream->EmitAbbrev(std::move(Abbv));
4376 
4377   Stream->EmitRecordWithBlob(AbbrevNo, ArrayRef<uint64_t>{Record}, Blob);
4378 
4379   Stream->ExitBlock();
4380 }
4381 
4382 void BitcodeWriter::writeSymtab() {
4383   assert(!WroteStrtab && !WroteSymtab);
4384 
4385   // If any module has module-level inline asm, we will require a registered asm
4386   // parser for the target so that we can create an accurate symbol table for
4387   // the module.
4388   for (Module *M : Mods) {
4389     if (M->getModuleInlineAsm().empty())
4390       continue;
4391 
4392     std::string Err;
4393     const Triple TT(M->getTargetTriple());
4394     const Target *T = TargetRegistry::lookupTarget(TT.str(), Err);
4395     if (!T || !T->hasMCAsmParser())
4396       return;
4397   }
4398 
4399   WroteSymtab = true;
4400   SmallVector<char, 0> Symtab;
4401   // The irsymtab::build function may be unable to create a symbol table if the
4402   // module is malformed (e.g. it contains an invalid alias). Writing a symbol
4403   // table is not required for correctness, but we still want to be able to
4404   // write malformed modules to bitcode files, so swallow the error.
4405   if (Error E = irsymtab::build(Mods, Symtab, StrtabBuilder, Alloc)) {
4406     consumeError(std::move(E));
4407     return;
4408   }
4409 
4410   writeBlob(bitc::SYMTAB_BLOCK_ID, bitc::SYMTAB_BLOB,
4411             {Symtab.data(), Symtab.size()});
4412 }
4413 
4414 void BitcodeWriter::writeStrtab() {
4415   assert(!WroteStrtab);
4416 
4417   std::vector<char> Strtab;
4418   StrtabBuilder.finalizeInOrder();
4419   Strtab.resize(StrtabBuilder.getSize());
4420   StrtabBuilder.write((uint8_t *)Strtab.data());
4421 
4422   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB,
4423             {Strtab.data(), Strtab.size()});
4424 
4425   WroteStrtab = true;
4426 }
4427 
4428 void BitcodeWriter::copyStrtab(StringRef Strtab) {
4429   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB, Strtab);
4430   WroteStrtab = true;
4431 }
4432 
4433 void BitcodeWriter::writeModule(const Module &M,
4434                                 bool ShouldPreserveUseListOrder,
4435                                 const ModuleSummaryIndex *Index,
4436                                 bool GenerateHash, ModuleHash *ModHash) {
4437   assert(!WroteStrtab);
4438 
4439   // The Mods vector is used by irsymtab::build, which requires non-const
4440   // Modules in case it needs to materialize metadata. But the bitcode writer
4441   // requires that the module is materialized, so we can cast to non-const here,
4442   // after checking that it is in fact materialized.
4443   assert(M.isMaterialized());
4444   Mods.push_back(const_cast<Module *>(&M));
4445 
4446   ModuleBitcodeWriter ModuleWriter(M, Buffer, StrtabBuilder, *Stream,
4447                                    ShouldPreserveUseListOrder, Index,
4448                                    GenerateHash, ModHash);
4449   ModuleWriter.write();
4450 }
4451 
4452 void BitcodeWriter::writeIndex(
4453     const ModuleSummaryIndex *Index,
4454     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4455   IndexBitcodeWriter IndexWriter(*Stream, StrtabBuilder, *Index,
4456                                  ModuleToSummariesForIndex);
4457   IndexWriter.write();
4458 }
4459 
4460 /// Write the specified module to the specified output stream.
4461 void llvm::WriteBitcodeToFile(const Module &M, raw_ostream &Out,
4462                               bool ShouldPreserveUseListOrder,
4463                               const ModuleSummaryIndex *Index,
4464                               bool GenerateHash, ModuleHash *ModHash) {
4465   SmallVector<char, 0> Buffer;
4466   Buffer.reserve(256*1024);
4467 
4468   // If this is darwin or another generic macho target, reserve space for the
4469   // header.
4470   Triple TT(M.getTargetTriple());
4471   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4472     Buffer.insert(Buffer.begin(), BWH_HeaderSize, 0);
4473 
4474   BitcodeWriter Writer(Buffer);
4475   Writer.writeModule(M, ShouldPreserveUseListOrder, Index, GenerateHash,
4476                      ModHash);
4477   Writer.writeSymtab();
4478   Writer.writeStrtab();
4479 
4480   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4481     emitDarwinBCHeaderAndTrailer(Buffer, TT);
4482 
4483   // Write the generated bitstream to "Out".
4484   Out.write((char*)&Buffer.front(), Buffer.size());
4485 }
4486 
4487 void IndexBitcodeWriter::write() {
4488   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4489 
4490   writeModuleVersion();
4491 
4492   // Write the module paths in the combined index.
4493   writeModStrings();
4494 
4495   // Write the summary combined index records.
4496   writeCombinedGlobalValueSummary();
4497 
4498   Stream.ExitBlock();
4499 }
4500 
4501 // Write the specified module summary index to the given raw output stream,
4502 // where it will be written in a new bitcode block. This is used when
4503 // writing the combined index file for ThinLTO. When writing a subset of the
4504 // index for a distributed backend, provide a \p ModuleToSummariesForIndex map.
4505 void llvm::WriteIndexToFile(
4506     const ModuleSummaryIndex &Index, raw_ostream &Out,
4507     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4508   SmallVector<char, 0> Buffer;
4509   Buffer.reserve(256 * 1024);
4510 
4511   BitcodeWriter Writer(Buffer);
4512   Writer.writeIndex(&Index, ModuleToSummariesForIndex);
4513   Writer.writeStrtab();
4514 
4515   Out.write((char *)&Buffer.front(), Buffer.size());
4516 }
4517 
4518 namespace {
4519 
4520 /// Class to manage the bitcode writing for a thin link bitcode file.
4521 class ThinLinkBitcodeWriter : public ModuleBitcodeWriterBase {
4522   /// ModHash is for use in ThinLTO incremental build, generated while writing
4523   /// the module bitcode file.
4524   const ModuleHash *ModHash;
4525 
4526 public:
4527   ThinLinkBitcodeWriter(const Module &M, StringTableBuilder &StrtabBuilder,
4528                         BitstreamWriter &Stream,
4529                         const ModuleSummaryIndex &Index,
4530                         const ModuleHash &ModHash)
4531       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
4532                                 /*ShouldPreserveUseListOrder=*/false, &Index),
4533         ModHash(&ModHash) {}
4534 
4535   void write();
4536 
4537 private:
4538   void writeSimplifiedModuleInfo();
4539 };
4540 
4541 } // end anonymous namespace
4542 
4543 // This function writes a simpilified module info for thin link bitcode file.
4544 // It only contains the source file name along with the name(the offset and
4545 // size in strtab) and linkage for global values. For the global value info
4546 // entry, in order to keep linkage at offset 5, there are three zeros used
4547 // as padding.
4548 void ThinLinkBitcodeWriter::writeSimplifiedModuleInfo() {
4549   SmallVector<unsigned, 64> Vals;
4550   // Emit the module's source file name.
4551   {
4552     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
4553     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
4554     if (Bits == SE_Char6)
4555       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
4556     else if (Bits == SE_Fixed7)
4557       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
4558 
4559     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
4560     auto Abbv = std::make_shared<BitCodeAbbrev>();
4561     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
4562     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4563     Abbv->Add(AbbrevOpToUse);
4564     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4565 
4566     for (const auto P : M.getSourceFileName())
4567       Vals.push_back((unsigned char)P);
4568 
4569     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
4570     Vals.clear();
4571   }
4572 
4573   // Emit the global variable information.
4574   for (const GlobalVariable &GV : M.globals()) {
4575     // GLOBALVAR: [strtab offset, strtab size, 0, 0, 0, linkage]
4576     Vals.push_back(StrtabBuilder.add(GV.getName()));
4577     Vals.push_back(GV.getName().size());
4578     Vals.push_back(0);
4579     Vals.push_back(0);
4580     Vals.push_back(0);
4581     Vals.push_back(getEncodedLinkage(GV));
4582 
4583     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals);
4584     Vals.clear();
4585   }
4586 
4587   // Emit the function proto information.
4588   for (const Function &F : M) {
4589     // FUNCTION:  [strtab offset, strtab size, 0, 0, 0, linkage]
4590     Vals.push_back(StrtabBuilder.add(F.getName()));
4591     Vals.push_back(F.getName().size());
4592     Vals.push_back(0);
4593     Vals.push_back(0);
4594     Vals.push_back(0);
4595     Vals.push_back(getEncodedLinkage(F));
4596 
4597     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals);
4598     Vals.clear();
4599   }
4600 
4601   // Emit the alias information.
4602   for (const GlobalAlias &A : M.aliases()) {
4603     // ALIAS: [strtab offset, strtab size, 0, 0, 0, linkage]
4604     Vals.push_back(StrtabBuilder.add(A.getName()));
4605     Vals.push_back(A.getName().size());
4606     Vals.push_back(0);
4607     Vals.push_back(0);
4608     Vals.push_back(0);
4609     Vals.push_back(getEncodedLinkage(A));
4610 
4611     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals);
4612     Vals.clear();
4613   }
4614 
4615   // Emit the ifunc information.
4616   for (const GlobalIFunc &I : M.ifuncs()) {
4617     // IFUNC: [strtab offset, strtab size, 0, 0, 0, linkage]
4618     Vals.push_back(StrtabBuilder.add(I.getName()));
4619     Vals.push_back(I.getName().size());
4620     Vals.push_back(0);
4621     Vals.push_back(0);
4622     Vals.push_back(0);
4623     Vals.push_back(getEncodedLinkage(I));
4624 
4625     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
4626     Vals.clear();
4627   }
4628 }
4629 
4630 void ThinLinkBitcodeWriter::write() {
4631   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4632 
4633   writeModuleVersion();
4634 
4635   writeSimplifiedModuleInfo();
4636 
4637   writePerModuleGlobalValueSummary();
4638 
4639   // Write module hash.
4640   Stream.EmitRecord(bitc::MODULE_CODE_HASH, ArrayRef<uint32_t>(*ModHash));
4641 
4642   Stream.ExitBlock();
4643 }
4644 
4645 void BitcodeWriter::writeThinLinkBitcode(const Module &M,
4646                                          const ModuleSummaryIndex &Index,
4647                                          const ModuleHash &ModHash) {
4648   assert(!WroteStrtab);
4649 
4650   // The Mods vector is used by irsymtab::build, which requires non-const
4651   // Modules in case it needs to materialize metadata. But the bitcode writer
4652   // requires that the module is materialized, so we can cast to non-const here,
4653   // after checking that it is in fact materialized.
4654   assert(M.isMaterialized());
4655   Mods.push_back(const_cast<Module *>(&M));
4656 
4657   ThinLinkBitcodeWriter ThinLinkWriter(M, StrtabBuilder, *Stream, Index,
4658                                        ModHash);
4659   ThinLinkWriter.write();
4660 }
4661 
4662 // Write the specified thin link bitcode file to the given raw output stream,
4663 // where it will be written in a new bitcode block. This is used when
4664 // writing the per-module index file for ThinLTO.
4665 void llvm::WriteThinLinkBitcodeToFile(const Module &M, raw_ostream &Out,
4666                                       const ModuleSummaryIndex &Index,
4667                                       const ModuleHash &ModHash) {
4668   SmallVector<char, 0> Buffer;
4669   Buffer.reserve(256 * 1024);
4670 
4671   BitcodeWriter Writer(Buffer);
4672   Writer.writeThinLinkBitcode(M, Index, ModHash);
4673   Writer.writeSymtab();
4674   Writer.writeStrtab();
4675 
4676   Out.write((char *)&Buffer.front(), Buffer.size());
4677 }
4678 
4679 static const char *getSectionNameForBitcode(const Triple &T) {
4680   switch (T.getObjectFormat()) {
4681   case Triple::MachO:
4682     return "__LLVM,__bitcode";
4683   case Triple::COFF:
4684   case Triple::ELF:
4685   case Triple::Wasm:
4686   case Triple::UnknownObjectFormat:
4687     return ".llvmbc";
4688   case Triple::XCOFF:
4689     llvm_unreachable("XCOFF is not yet implemented");
4690     break;
4691   }
4692   llvm_unreachable("Unimplemented ObjectFormatType");
4693 }
4694 
4695 static const char *getSectionNameForCommandline(const Triple &T) {
4696   switch (T.getObjectFormat()) {
4697   case Triple::MachO:
4698     return "__LLVM,__cmdline";
4699   case Triple::COFF:
4700   case Triple::ELF:
4701   case Triple::Wasm:
4702   case Triple::UnknownObjectFormat:
4703     return ".llvmcmd";
4704   case Triple::XCOFF:
4705     llvm_unreachable("XCOFF is not yet implemented");
4706     break;
4707   }
4708   llvm_unreachable("Unimplemented ObjectFormatType");
4709 }
4710 
4711 void llvm::EmbedBitcodeInModule(llvm::Module &M, llvm::MemoryBufferRef Buf,
4712                                 bool EmbedBitcode, bool EmbedMarker,
4713                                 const std::vector<uint8_t> *CmdArgs) {
4714   // Save llvm.compiler.used and remove it.
4715   SmallVector<Constant *, 2> UsedArray;
4716   SmallPtrSet<GlobalValue *, 4> UsedGlobals;
4717   Type *UsedElementType = Type::getInt8Ty(M.getContext())->getPointerTo(0);
4718   GlobalVariable *Used = collectUsedGlobalVariables(M, UsedGlobals, true);
4719   for (auto *GV : UsedGlobals) {
4720     if (GV->getName() != "llvm.embedded.module" &&
4721         GV->getName() != "llvm.cmdline")
4722       UsedArray.push_back(
4723           ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
4724   }
4725   if (Used)
4726     Used->eraseFromParent();
4727 
4728   // Embed the bitcode for the llvm module.
4729   std::string Data;
4730   ArrayRef<uint8_t> ModuleData;
4731   Triple T(M.getTargetTriple());
4732   // Create a constant that contains the bitcode.
4733   // In case of embedding a marker, ignore the input Buf and use the empty
4734   // ArrayRef. It is also legal to create a bitcode marker even Buf is empty.
4735   if (EmbedBitcode) {
4736     if (!isBitcode((const unsigned char *)Buf.getBufferStart(),
4737                    (const unsigned char *)Buf.getBufferEnd())) {
4738       // If the input is LLVM Assembly, bitcode is produced by serializing
4739       // the module. Use-lists order need to be preserved in this case.
4740       llvm::raw_string_ostream OS(Data);
4741       llvm::WriteBitcodeToFile(M, OS, /* ShouldPreserveUseListOrder */ true);
4742       ModuleData =
4743           ArrayRef<uint8_t>((const uint8_t *)OS.str().data(), OS.str().size());
4744     } else
4745       // If the input is LLVM bitcode, write the input byte stream directly.
4746       ModuleData = ArrayRef<uint8_t>((const uint8_t *)Buf.getBufferStart(),
4747                                      Buf.getBufferSize());
4748   }
4749   llvm::Constant *ModuleConstant =
4750       llvm::ConstantDataArray::get(M.getContext(), ModuleData);
4751   llvm::GlobalVariable *GV = new llvm::GlobalVariable(
4752       M, ModuleConstant->getType(), true, llvm::GlobalValue::PrivateLinkage,
4753       ModuleConstant);
4754   GV->setSection(getSectionNameForBitcode(T));
4755   UsedArray.push_back(
4756       ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
4757   if (llvm::GlobalVariable *Old =
4758           M.getGlobalVariable("llvm.embedded.module", true)) {
4759     assert(Old->hasOneUse() &&
4760            "llvm.embedded.module can only be used once in llvm.compiler.used");
4761     GV->takeName(Old);
4762     Old->eraseFromParent();
4763   } else {
4764     GV->setName("llvm.embedded.module");
4765   }
4766 
4767   // Skip if only bitcode needs to be embedded.
4768   if (EmbedMarker) {
4769     // Embed command-line options.
4770     ArrayRef<uint8_t> CmdData(const_cast<uint8_t *>(CmdArgs->data()),
4771                               CmdArgs->size());
4772     llvm::Constant *CmdConstant =
4773         llvm::ConstantDataArray::get(M.getContext(), CmdData);
4774     GV = new llvm::GlobalVariable(M, CmdConstant->getType(), true,
4775                                   llvm::GlobalValue::PrivateLinkage,
4776                                   CmdConstant);
4777     GV->setSection(getSectionNameForCommandline(T));
4778     UsedArray.push_back(
4779         ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
4780     if (llvm::GlobalVariable *Old = M.getGlobalVariable("llvm.cmdline", true)) {
4781       assert(Old->hasOneUse() &&
4782              "llvm.cmdline can only be used once in llvm.compiler.used");
4783       GV->takeName(Old);
4784       Old->eraseFromParent();
4785     } else {
4786       GV->setName("llvm.cmdline");
4787     }
4788   }
4789 
4790   if (UsedArray.empty())
4791     return;
4792 
4793   // Recreate llvm.compiler.used.
4794   ArrayType *ATy = ArrayType::get(UsedElementType, UsedArray.size());
4795   auto *NewUsed = new GlobalVariable(
4796       M, ATy, false, llvm::GlobalValue::AppendingLinkage,
4797       llvm::ConstantArray::get(ATy, UsedArray), "llvm.compiler.used");
4798   NewUsed->setSection("llvm.metadata");
4799 }
4800