xref: /llvm-project/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp (revision bf46e7410c8a1d26c4a434261baaae28a904d657)
1 //===- Bitcode/Writer/BitcodeWriter.cpp - Bitcode Writer ------------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // Bitcode writer implementation.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "llvm/Bitcode/BitcodeWriter.h"
15 #include "ValueEnumerator.h"
16 #include "llvm/ADT/APFloat.h"
17 #include "llvm/ADT/APInt.h"
18 #include "llvm/ADT/ArrayRef.h"
19 #include "llvm/ADT/DenseMap.h"
20 #include "llvm/ADT/None.h"
21 #include "llvm/ADT/Optional.h"
22 #include "llvm/ADT/STLExtras.h"
23 #include "llvm/ADT/SmallString.h"
24 #include "llvm/ADT/SmallVector.h"
25 #include "llvm/ADT/StringMap.h"
26 #include "llvm/ADT/StringRef.h"
27 #include "llvm/ADT/Triple.h"
28 #include "llvm/Bitcode/BitCodes.h"
29 #include "llvm/Bitcode/BitstreamWriter.h"
30 #include "llvm/Bitcode/LLVMBitCodes.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 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 
220   void assignValueId(GlobalValue::GUID ValGUID) {
221     GUIDToValueIdMap[ValGUID] = ++GlobalValueId;
222   }
223 
224   unsigned getValueId(GlobalValue::GUID ValGUID) {
225     const auto &VMI = GUIDToValueIdMap.find(ValGUID);
226     // Expect that any GUID value had a value Id assigned by an
227     // earlier call to assignValueId.
228     assert(VMI != GUIDToValueIdMap.end() &&
229            "GUID does not have assigned value Id");
230     return VMI->second;
231   }
232 
233   // Helper to get the valueId for the type of value recorded in VI.
234   unsigned getValueId(ValueInfo VI) {
235     if (!VI.haveGVs() || !VI.getValue())
236       return getValueId(VI.getGUID());
237     return VE.getValueID(VI.getValue());
238   }
239 
240   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
241 };
242 
243 /// Class to manage the bitcode writing for a module.
244 class ModuleBitcodeWriter : public ModuleBitcodeWriterBase {
245   /// Pointer to the buffer allocated by caller for bitcode writing.
246   const SmallVectorImpl<char> &Buffer;
247 
248   /// True if a module hash record should be written.
249   bool GenerateHash;
250 
251   /// If non-null, when GenerateHash is true, the resulting hash is written
252   /// into ModHash.
253   ModuleHash *ModHash;
254 
255   SHA1 Hasher;
256 
257   /// The start bit of the identification block.
258   uint64_t BitcodeStartBit;
259 
260 public:
261   /// Constructs a ModuleBitcodeWriter object for the given Module,
262   /// writing to the provided \p Buffer.
263   ModuleBitcodeWriter(const Module &M, SmallVectorImpl<char> &Buffer,
264                       StringTableBuilder &StrtabBuilder,
265                       BitstreamWriter &Stream, bool ShouldPreserveUseListOrder,
266                       const ModuleSummaryIndex *Index, bool GenerateHash,
267                       ModuleHash *ModHash = nullptr)
268       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
269                                 ShouldPreserveUseListOrder, Index),
270         Buffer(Buffer), GenerateHash(GenerateHash), ModHash(ModHash),
271         BitcodeStartBit(Stream.GetCurrentBitNo()) {}
272 
273   /// Emit the current module to the bitstream.
274   void write();
275 
276 private:
277   uint64_t bitcodeStartBit() { return BitcodeStartBit; }
278 
279   size_t addToStrtab(StringRef Str);
280 
281   void writeAttributeGroupTable();
282   void writeAttributeTable();
283   void writeTypeTable();
284   void writeComdats();
285   void writeValueSymbolTableForwardDecl();
286   void writeModuleInfo();
287   void writeValueAsMetadata(const ValueAsMetadata *MD,
288                             SmallVectorImpl<uint64_t> &Record);
289   void writeMDTuple(const MDTuple *N, SmallVectorImpl<uint64_t> &Record,
290                     unsigned Abbrev);
291   unsigned createDILocationAbbrev();
292   void writeDILocation(const DILocation *N, SmallVectorImpl<uint64_t> &Record,
293                        unsigned &Abbrev);
294   unsigned createGenericDINodeAbbrev();
295   void writeGenericDINode(const GenericDINode *N,
296                           SmallVectorImpl<uint64_t> &Record, unsigned &Abbrev);
297   void writeDISubrange(const DISubrange *N, SmallVectorImpl<uint64_t> &Record,
298                        unsigned Abbrev);
299   void writeDIEnumerator(const DIEnumerator *N,
300                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
301   void writeDIBasicType(const DIBasicType *N, SmallVectorImpl<uint64_t> &Record,
302                         unsigned Abbrev);
303   void writeDIDerivedType(const DIDerivedType *N,
304                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
305   void writeDICompositeType(const DICompositeType *N,
306                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
307   void writeDISubroutineType(const DISubroutineType *N,
308                              SmallVectorImpl<uint64_t> &Record,
309                              unsigned Abbrev);
310   void writeDIFile(const DIFile *N, SmallVectorImpl<uint64_t> &Record,
311                    unsigned Abbrev);
312   void writeDICompileUnit(const DICompileUnit *N,
313                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
314   void writeDISubprogram(const DISubprogram *N,
315                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
316   void writeDILexicalBlock(const DILexicalBlock *N,
317                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
318   void writeDILexicalBlockFile(const DILexicalBlockFile *N,
319                                SmallVectorImpl<uint64_t> &Record,
320                                unsigned Abbrev);
321   void writeDINamespace(const DINamespace *N, SmallVectorImpl<uint64_t> &Record,
322                         unsigned Abbrev);
323   void writeDIMacro(const DIMacro *N, SmallVectorImpl<uint64_t> &Record,
324                     unsigned Abbrev);
325   void writeDIMacroFile(const DIMacroFile *N, SmallVectorImpl<uint64_t> &Record,
326                         unsigned Abbrev);
327   void writeDIModule(const DIModule *N, SmallVectorImpl<uint64_t> &Record,
328                      unsigned Abbrev);
329   void writeDITemplateTypeParameter(const DITemplateTypeParameter *N,
330                                     SmallVectorImpl<uint64_t> &Record,
331                                     unsigned Abbrev);
332   void writeDITemplateValueParameter(const DITemplateValueParameter *N,
333                                      SmallVectorImpl<uint64_t> &Record,
334                                      unsigned Abbrev);
335   void writeDIGlobalVariable(const DIGlobalVariable *N,
336                              SmallVectorImpl<uint64_t> &Record,
337                              unsigned Abbrev);
338   void writeDILocalVariable(const DILocalVariable *N,
339                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
340   void writeDILabel(const DILabel *N,
341                     SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
342   void writeDIExpression(const DIExpression *N,
343                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
344   void writeDIGlobalVariableExpression(const DIGlobalVariableExpression *N,
345                                        SmallVectorImpl<uint64_t> &Record,
346                                        unsigned Abbrev);
347   void writeDIObjCProperty(const DIObjCProperty *N,
348                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
349   void writeDIImportedEntity(const DIImportedEntity *N,
350                              SmallVectorImpl<uint64_t> &Record,
351                              unsigned Abbrev);
352   unsigned createNamedMetadataAbbrev();
353   void writeNamedMetadata(SmallVectorImpl<uint64_t> &Record);
354   unsigned createMetadataStringsAbbrev();
355   void writeMetadataStrings(ArrayRef<const Metadata *> Strings,
356                             SmallVectorImpl<uint64_t> &Record);
357   void writeMetadataRecords(ArrayRef<const Metadata *> MDs,
358                             SmallVectorImpl<uint64_t> &Record,
359                             std::vector<unsigned> *MDAbbrevs = nullptr,
360                             std::vector<uint64_t> *IndexPos = nullptr);
361   void writeModuleMetadata();
362   void writeFunctionMetadata(const Function &F);
363   void writeFunctionMetadataAttachment(const Function &F);
364   void writeGlobalVariableMetadataAttachment(const GlobalVariable &GV);
365   void pushGlobalMetadataAttachment(SmallVectorImpl<uint64_t> &Record,
366                                     const GlobalObject &GO);
367   void writeModuleMetadataKinds();
368   void writeOperandBundleTags();
369   void writeSyncScopeNames();
370   void writeConstants(unsigned FirstVal, unsigned LastVal, bool isGlobal);
371   void writeModuleConstants();
372   bool pushValueAndType(const Value *V, unsigned InstID,
373                         SmallVectorImpl<unsigned> &Vals);
374   void writeOperandBundles(ImmutableCallSite CS, unsigned InstID);
375   void pushValue(const Value *V, unsigned InstID,
376                  SmallVectorImpl<unsigned> &Vals);
377   void pushValueSigned(const Value *V, unsigned InstID,
378                        SmallVectorImpl<uint64_t> &Vals);
379   void writeInstruction(const Instruction &I, unsigned InstID,
380                         SmallVectorImpl<unsigned> &Vals);
381   void writeFunctionLevelValueSymbolTable(const ValueSymbolTable &VST);
382   void writeGlobalValueSymbolTable(
383       DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
384   void writeUseList(UseListOrder &&Order);
385   void writeUseListBlock(const Function *F);
386   void
387   writeFunction(const Function &F,
388                 DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
389   void writeBlockInfo();
390   void writeModuleHash(size_t BlockStartPos);
391 
392   unsigned getEncodedSyncScopeID(SyncScope::ID SSID) {
393     return unsigned(SSID);
394   }
395 };
396 
397 /// Class to manage the bitcode writing for a combined index.
398 class IndexBitcodeWriter : public BitcodeWriterBase {
399   /// The combined index to write to bitcode.
400   const ModuleSummaryIndex &Index;
401 
402   /// When writing a subset of the index for distributed backends, client
403   /// provides a map of modules to the corresponding GUIDs/summaries to write.
404   const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex;
405 
406   /// Map that holds the correspondence between the GUID used in the combined
407   /// index and a value id generated by this class to use in references.
408   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
409 
410   /// Tracks the last value id recorded in the GUIDToValueMap.
411   unsigned GlobalValueId = 0;
412 
413 public:
414   /// Constructs a IndexBitcodeWriter object for the given combined index,
415   /// writing to the provided \p Buffer. When writing a subset of the index
416   /// for a distributed backend, provide a \p ModuleToSummariesForIndex map.
417   IndexBitcodeWriter(BitstreamWriter &Stream, StringTableBuilder &StrtabBuilder,
418                      const ModuleSummaryIndex &Index,
419                      const std::map<std::string, GVSummaryMapTy>
420                          *ModuleToSummariesForIndex = nullptr)
421       : BitcodeWriterBase(Stream, StrtabBuilder), Index(Index),
422         ModuleToSummariesForIndex(ModuleToSummariesForIndex) {
423     // Assign unique value ids to all summaries to be written, for use
424     // in writing out the call graph edges. Save the mapping from GUID
425     // to the new global value id to use when writing those edges, which
426     // are currently saved in the index in terms of GUID.
427     forEachSummary([&](GVInfo I, bool) {
428       GUIDToValueIdMap[I.first] = ++GlobalValueId;
429     });
430   }
431 
432   /// The below iterator returns the GUID and associated summary.
433   using GVInfo = std::pair<GlobalValue::GUID, GlobalValueSummary *>;
434 
435   /// Calls the callback for each value GUID and summary to be written to
436   /// bitcode. This hides the details of whether they are being pulled from the
437   /// entire index or just those in a provided ModuleToSummariesForIndex map.
438   template<typename Functor>
439   void forEachSummary(Functor Callback) {
440     if (ModuleToSummariesForIndex) {
441       for (auto &M : *ModuleToSummariesForIndex)
442         for (auto &Summary : M.second) {
443           Callback(Summary, false);
444           // Ensure aliasee is handled, e.g. for assigning a valueId,
445           // even if we are not importing the aliasee directly (the
446           // imported alias will contain a copy of aliasee).
447           if (auto *AS = dyn_cast<AliasSummary>(Summary.getSecond()))
448             Callback({AS->getAliaseeGUID(), &AS->getAliasee()}, true);
449         }
450     } else {
451       for (auto &Summaries : Index)
452         for (auto &Summary : Summaries.second.SummaryList)
453           Callback({Summaries.first, Summary.get()}, false);
454     }
455   }
456 
457   /// Calls the callback for each entry in the modulePaths StringMap that
458   /// should be written to the module path string table. This hides the details
459   /// of whether they are being pulled from the entire index or just those in a
460   /// provided ModuleToSummariesForIndex map.
461   template <typename Functor> void forEachModule(Functor Callback) {
462     if (ModuleToSummariesForIndex) {
463       for (const auto &M : *ModuleToSummariesForIndex) {
464         const auto &MPI = Index.modulePaths().find(M.first);
465         if (MPI == Index.modulePaths().end()) {
466           // This should only happen if the bitcode file was empty, in which
467           // case we shouldn't be importing (the ModuleToSummariesForIndex
468           // would only include the module we are writing and index for).
469           assert(ModuleToSummariesForIndex->size() == 1);
470           continue;
471         }
472         Callback(*MPI);
473       }
474     } else {
475       for (const auto &MPSE : Index.modulePaths())
476         Callback(MPSE);
477     }
478   }
479 
480   /// Main entry point for writing a combined index to bitcode.
481   void write();
482 
483 private:
484   void writeModStrings();
485   void writeCombinedGlobalValueSummary();
486 
487   Optional<unsigned> getValueId(GlobalValue::GUID ValGUID) {
488     auto VMI = GUIDToValueIdMap.find(ValGUID);
489     if (VMI == GUIDToValueIdMap.end())
490       return None;
491     return VMI->second;
492   }
493 
494   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
495 };
496 
497 } // end anonymous namespace
498 
499 static unsigned getEncodedCastOpcode(unsigned Opcode) {
500   switch (Opcode) {
501   default: llvm_unreachable("Unknown cast instruction!");
502   case Instruction::Trunc   : return bitc::CAST_TRUNC;
503   case Instruction::ZExt    : return bitc::CAST_ZEXT;
504   case Instruction::SExt    : return bitc::CAST_SEXT;
505   case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
506   case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
507   case Instruction::UIToFP  : return bitc::CAST_UITOFP;
508   case Instruction::SIToFP  : return bitc::CAST_SITOFP;
509   case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
510   case Instruction::FPExt   : return bitc::CAST_FPEXT;
511   case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
512   case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
513   case Instruction::BitCast : return bitc::CAST_BITCAST;
514   case Instruction::AddrSpaceCast: return bitc::CAST_ADDRSPACECAST;
515   }
516 }
517 
518 static unsigned getEncodedUnaryOpcode(unsigned Opcode) {
519   switch (Opcode) {
520   default: llvm_unreachable("Unknown binary instruction!");
521   case Instruction::FNeg: return bitc::UNOP_NEG;
522   }
523 }
524 
525 static unsigned getEncodedBinaryOpcode(unsigned Opcode) {
526   switch (Opcode) {
527   default: llvm_unreachable("Unknown binary instruction!");
528   case Instruction::Add:
529   case Instruction::FAdd: return bitc::BINOP_ADD;
530   case Instruction::Sub:
531   case Instruction::FSub: return bitc::BINOP_SUB;
532   case Instruction::Mul:
533   case Instruction::FMul: return bitc::BINOP_MUL;
534   case Instruction::UDiv: return bitc::BINOP_UDIV;
535   case Instruction::FDiv:
536   case Instruction::SDiv: return bitc::BINOP_SDIV;
537   case Instruction::URem: return bitc::BINOP_UREM;
538   case Instruction::FRem:
539   case Instruction::SRem: return bitc::BINOP_SREM;
540   case Instruction::Shl:  return bitc::BINOP_SHL;
541   case Instruction::LShr: return bitc::BINOP_LSHR;
542   case Instruction::AShr: return bitc::BINOP_ASHR;
543   case Instruction::And:  return bitc::BINOP_AND;
544   case Instruction::Or:   return bitc::BINOP_OR;
545   case Instruction::Xor:  return bitc::BINOP_XOR;
546   }
547 }
548 
549 static unsigned getEncodedRMWOperation(AtomicRMWInst::BinOp Op) {
550   switch (Op) {
551   default: llvm_unreachable("Unknown RMW operation!");
552   case AtomicRMWInst::Xchg: return bitc::RMW_XCHG;
553   case AtomicRMWInst::Add: return bitc::RMW_ADD;
554   case AtomicRMWInst::Sub: return bitc::RMW_SUB;
555   case AtomicRMWInst::And: return bitc::RMW_AND;
556   case AtomicRMWInst::Nand: return bitc::RMW_NAND;
557   case AtomicRMWInst::Or: return bitc::RMW_OR;
558   case AtomicRMWInst::Xor: return bitc::RMW_XOR;
559   case AtomicRMWInst::Max: return bitc::RMW_MAX;
560   case AtomicRMWInst::Min: return bitc::RMW_MIN;
561   case AtomicRMWInst::UMax: return bitc::RMW_UMAX;
562   case AtomicRMWInst::UMin: return bitc::RMW_UMIN;
563   }
564 }
565 
566 static unsigned getEncodedOrdering(AtomicOrdering Ordering) {
567   switch (Ordering) {
568   case AtomicOrdering::NotAtomic: return bitc::ORDERING_NOTATOMIC;
569   case AtomicOrdering::Unordered: return bitc::ORDERING_UNORDERED;
570   case AtomicOrdering::Monotonic: return bitc::ORDERING_MONOTONIC;
571   case AtomicOrdering::Acquire: return bitc::ORDERING_ACQUIRE;
572   case AtomicOrdering::Release: return bitc::ORDERING_RELEASE;
573   case AtomicOrdering::AcquireRelease: return bitc::ORDERING_ACQREL;
574   case AtomicOrdering::SequentiallyConsistent: return bitc::ORDERING_SEQCST;
575   }
576   llvm_unreachable("Invalid ordering");
577 }
578 
579 static void writeStringRecord(BitstreamWriter &Stream, unsigned Code,
580                               StringRef Str, unsigned AbbrevToUse) {
581   SmallVector<unsigned, 64> Vals;
582 
583   // Code: [strchar x N]
584   for (unsigned i = 0, e = Str.size(); i != e; ++i) {
585     if (AbbrevToUse && !BitCodeAbbrevOp::isChar6(Str[i]))
586       AbbrevToUse = 0;
587     Vals.push_back(Str[i]);
588   }
589 
590   // Emit the finished record.
591   Stream.EmitRecord(Code, Vals, AbbrevToUse);
592 }
593 
594 static uint64_t getAttrKindEncoding(Attribute::AttrKind Kind) {
595   switch (Kind) {
596   case Attribute::Alignment:
597     return bitc::ATTR_KIND_ALIGNMENT;
598   case Attribute::AllocSize:
599     return bitc::ATTR_KIND_ALLOC_SIZE;
600   case Attribute::AlwaysInline:
601     return bitc::ATTR_KIND_ALWAYS_INLINE;
602   case Attribute::ArgMemOnly:
603     return bitc::ATTR_KIND_ARGMEMONLY;
604   case Attribute::Builtin:
605     return bitc::ATTR_KIND_BUILTIN;
606   case Attribute::ByVal:
607     return bitc::ATTR_KIND_BY_VAL;
608   case Attribute::Convergent:
609     return bitc::ATTR_KIND_CONVERGENT;
610   case Attribute::InAlloca:
611     return bitc::ATTR_KIND_IN_ALLOCA;
612   case Attribute::Cold:
613     return bitc::ATTR_KIND_COLD;
614   case Attribute::InaccessibleMemOnly:
615     return bitc::ATTR_KIND_INACCESSIBLEMEM_ONLY;
616   case Attribute::InaccessibleMemOrArgMemOnly:
617     return bitc::ATTR_KIND_INACCESSIBLEMEM_OR_ARGMEMONLY;
618   case Attribute::InlineHint:
619     return bitc::ATTR_KIND_INLINE_HINT;
620   case Attribute::InReg:
621     return bitc::ATTR_KIND_IN_REG;
622   case Attribute::JumpTable:
623     return bitc::ATTR_KIND_JUMP_TABLE;
624   case Attribute::MinSize:
625     return bitc::ATTR_KIND_MIN_SIZE;
626   case Attribute::Naked:
627     return bitc::ATTR_KIND_NAKED;
628   case Attribute::Nest:
629     return bitc::ATTR_KIND_NEST;
630   case Attribute::NoAlias:
631     return bitc::ATTR_KIND_NO_ALIAS;
632   case Attribute::NoBuiltin:
633     return bitc::ATTR_KIND_NO_BUILTIN;
634   case Attribute::NoCapture:
635     return bitc::ATTR_KIND_NO_CAPTURE;
636   case Attribute::NoDuplicate:
637     return bitc::ATTR_KIND_NO_DUPLICATE;
638   case Attribute::NoImplicitFloat:
639     return bitc::ATTR_KIND_NO_IMPLICIT_FLOAT;
640   case Attribute::NoInline:
641     return bitc::ATTR_KIND_NO_INLINE;
642   case Attribute::NoRecurse:
643     return bitc::ATTR_KIND_NO_RECURSE;
644   case Attribute::NonLazyBind:
645     return bitc::ATTR_KIND_NON_LAZY_BIND;
646   case Attribute::NonNull:
647     return bitc::ATTR_KIND_NON_NULL;
648   case Attribute::Dereferenceable:
649     return bitc::ATTR_KIND_DEREFERENCEABLE;
650   case Attribute::DereferenceableOrNull:
651     return bitc::ATTR_KIND_DEREFERENCEABLE_OR_NULL;
652   case Attribute::NoRedZone:
653     return bitc::ATTR_KIND_NO_RED_ZONE;
654   case Attribute::NoReturn:
655     return bitc::ATTR_KIND_NO_RETURN;
656   case Attribute::NoCfCheck:
657     return bitc::ATTR_KIND_NOCF_CHECK;
658   case Attribute::NoUnwind:
659     return bitc::ATTR_KIND_NO_UNWIND;
660   case Attribute::OptForFuzzing:
661     return bitc::ATTR_KIND_OPT_FOR_FUZZING;
662   case Attribute::OptimizeForSize:
663     return bitc::ATTR_KIND_OPTIMIZE_FOR_SIZE;
664   case Attribute::OptimizeNone:
665     return bitc::ATTR_KIND_OPTIMIZE_NONE;
666   case Attribute::ReadNone:
667     return bitc::ATTR_KIND_READ_NONE;
668   case Attribute::ReadOnly:
669     return bitc::ATTR_KIND_READ_ONLY;
670   case Attribute::Returned:
671     return bitc::ATTR_KIND_RETURNED;
672   case Attribute::ReturnsTwice:
673     return bitc::ATTR_KIND_RETURNS_TWICE;
674   case Attribute::SExt:
675     return bitc::ATTR_KIND_S_EXT;
676   case Attribute::Speculatable:
677     return bitc::ATTR_KIND_SPECULATABLE;
678   case Attribute::StackAlignment:
679     return bitc::ATTR_KIND_STACK_ALIGNMENT;
680   case Attribute::StackProtect:
681     return bitc::ATTR_KIND_STACK_PROTECT;
682   case Attribute::StackProtectReq:
683     return bitc::ATTR_KIND_STACK_PROTECT_REQ;
684   case Attribute::StackProtectStrong:
685     return bitc::ATTR_KIND_STACK_PROTECT_STRONG;
686   case Attribute::SafeStack:
687     return bitc::ATTR_KIND_SAFESTACK;
688   case Attribute::ShadowCallStack:
689     return bitc::ATTR_KIND_SHADOWCALLSTACK;
690   case Attribute::StrictFP:
691     return bitc::ATTR_KIND_STRICT_FP;
692   case Attribute::StructRet:
693     return bitc::ATTR_KIND_STRUCT_RET;
694   case Attribute::SanitizeAddress:
695     return bitc::ATTR_KIND_SANITIZE_ADDRESS;
696   case Attribute::SanitizeHWAddress:
697     return bitc::ATTR_KIND_SANITIZE_HWADDRESS;
698   case Attribute::SanitizeThread:
699     return bitc::ATTR_KIND_SANITIZE_THREAD;
700   case Attribute::SanitizeMemory:
701     return bitc::ATTR_KIND_SANITIZE_MEMORY;
702   case Attribute::SpeculativeLoadHardening:
703     return bitc::ATTR_KIND_SPECULATIVE_LOAD_HARDENING;
704   case Attribute::SwiftError:
705     return bitc::ATTR_KIND_SWIFT_ERROR;
706   case Attribute::SwiftSelf:
707     return bitc::ATTR_KIND_SWIFT_SELF;
708   case Attribute::UWTable:
709     return bitc::ATTR_KIND_UW_TABLE;
710   case Attribute::WriteOnly:
711     return bitc::ATTR_KIND_WRITEONLY;
712   case Attribute::ZExt:
713     return bitc::ATTR_KIND_Z_EXT;
714   case Attribute::EndAttrKinds:
715     llvm_unreachable("Can not encode end-attribute kinds marker.");
716   case Attribute::None:
717     llvm_unreachable("Can not encode none-attribute.");
718   }
719 
720   llvm_unreachable("Trying to encode unknown attribute");
721 }
722 
723 void ModuleBitcodeWriter::writeAttributeGroupTable() {
724   const std::vector<ValueEnumerator::IndexAndAttrSet> &AttrGrps =
725       VE.getAttributeGroups();
726   if (AttrGrps.empty()) return;
727 
728   Stream.EnterSubblock(bitc::PARAMATTR_GROUP_BLOCK_ID, 3);
729 
730   SmallVector<uint64_t, 64> Record;
731   for (ValueEnumerator::IndexAndAttrSet Pair : AttrGrps) {
732     unsigned AttrListIndex = Pair.first;
733     AttributeSet AS = Pair.second;
734     Record.push_back(VE.getAttributeGroupID(Pair));
735     Record.push_back(AttrListIndex);
736 
737     for (Attribute Attr : AS) {
738       if (Attr.isEnumAttribute()) {
739         Record.push_back(0);
740         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
741       } else if (Attr.isIntAttribute()) {
742         Record.push_back(1);
743         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
744         Record.push_back(Attr.getValueAsInt());
745       } else {
746         StringRef Kind = Attr.getKindAsString();
747         StringRef Val = Attr.getValueAsString();
748 
749         Record.push_back(Val.empty() ? 3 : 4);
750         Record.append(Kind.begin(), Kind.end());
751         Record.push_back(0);
752         if (!Val.empty()) {
753           Record.append(Val.begin(), Val.end());
754           Record.push_back(0);
755         }
756       }
757     }
758 
759     Stream.EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
760     Record.clear();
761   }
762 
763   Stream.ExitBlock();
764 }
765 
766 void ModuleBitcodeWriter::writeAttributeTable() {
767   const std::vector<AttributeList> &Attrs = VE.getAttributeLists();
768   if (Attrs.empty()) return;
769 
770   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
771 
772   SmallVector<uint64_t, 64> Record;
773   for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
774     AttributeList AL = Attrs[i];
775     for (unsigned i = AL.index_begin(), e = AL.index_end(); i != e; ++i) {
776       AttributeSet AS = AL.getAttributes(i);
777       if (AS.hasAttributes())
778         Record.push_back(VE.getAttributeGroupID({i, AS}));
779     }
780 
781     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
782     Record.clear();
783   }
784 
785   Stream.ExitBlock();
786 }
787 
788 /// WriteTypeTable - Write out the type table for a module.
789 void ModuleBitcodeWriter::writeTypeTable() {
790   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
791 
792   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
793   SmallVector<uint64_t, 64> TypeVals;
794 
795   uint64_t NumBits = VE.computeBitsRequiredForTypeIndicies();
796 
797   // Abbrev for TYPE_CODE_POINTER.
798   auto Abbv = std::make_shared<BitCodeAbbrev>();
799   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
800   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
801   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
802   unsigned PtrAbbrev = Stream.EmitAbbrev(std::move(Abbv));
803 
804   // Abbrev for TYPE_CODE_FUNCTION.
805   Abbv = std::make_shared<BitCodeAbbrev>();
806   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
807   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
808   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
809   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
810   unsigned FunctionAbbrev = Stream.EmitAbbrev(std::move(Abbv));
811 
812   // Abbrev for TYPE_CODE_STRUCT_ANON.
813   Abbv = std::make_shared<BitCodeAbbrev>();
814   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
815   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
816   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
817   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
818   unsigned StructAnonAbbrev = Stream.EmitAbbrev(std::move(Abbv));
819 
820   // Abbrev for TYPE_CODE_STRUCT_NAME.
821   Abbv = std::make_shared<BitCodeAbbrev>();
822   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
823   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
824   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
825   unsigned StructNameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
826 
827   // Abbrev for TYPE_CODE_STRUCT_NAMED.
828   Abbv = std::make_shared<BitCodeAbbrev>();
829   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
830   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
831   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
832   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
833   unsigned StructNamedAbbrev = Stream.EmitAbbrev(std::move(Abbv));
834 
835   // Abbrev for TYPE_CODE_ARRAY.
836   Abbv = std::make_shared<BitCodeAbbrev>();
837   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
838   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
839   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
840   unsigned ArrayAbbrev = Stream.EmitAbbrev(std::move(Abbv));
841 
842   // Emit an entry count so the reader can reserve space.
843   TypeVals.push_back(TypeList.size());
844   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
845   TypeVals.clear();
846 
847   // Loop over all of the types, emitting each in turn.
848   for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
849     Type *T = TypeList[i];
850     int AbbrevToUse = 0;
851     unsigned Code = 0;
852 
853     switch (T->getTypeID()) {
854     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;      break;
855     case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;      break;
856     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;     break;
857     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE;    break;
858     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80;  break;
859     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128;     break;
860     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
861     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;     break;
862     case Type::MetadataTyID:  Code = bitc::TYPE_CODE_METADATA;  break;
863     case Type::X86_MMXTyID:   Code = bitc::TYPE_CODE_X86_MMX;   break;
864     case Type::TokenTyID:     Code = bitc::TYPE_CODE_TOKEN;     break;
865     case Type::IntegerTyID:
866       // INTEGER: [width]
867       Code = bitc::TYPE_CODE_INTEGER;
868       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
869       break;
870     case Type::PointerTyID: {
871       PointerType *PTy = cast<PointerType>(T);
872       // POINTER: [pointee type, address space]
873       Code = bitc::TYPE_CODE_POINTER;
874       TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
875       unsigned AddressSpace = PTy->getAddressSpace();
876       TypeVals.push_back(AddressSpace);
877       if (AddressSpace == 0) AbbrevToUse = PtrAbbrev;
878       break;
879     }
880     case Type::FunctionTyID: {
881       FunctionType *FT = cast<FunctionType>(T);
882       // FUNCTION: [isvararg, retty, paramty x N]
883       Code = bitc::TYPE_CODE_FUNCTION;
884       TypeVals.push_back(FT->isVarArg());
885       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
886       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
887         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
888       AbbrevToUse = FunctionAbbrev;
889       break;
890     }
891     case Type::StructTyID: {
892       StructType *ST = cast<StructType>(T);
893       // STRUCT: [ispacked, eltty x N]
894       TypeVals.push_back(ST->isPacked());
895       // Output all of the element types.
896       for (StructType::element_iterator I = ST->element_begin(),
897            E = ST->element_end(); I != E; ++I)
898         TypeVals.push_back(VE.getTypeID(*I));
899 
900       if (ST->isLiteral()) {
901         Code = bitc::TYPE_CODE_STRUCT_ANON;
902         AbbrevToUse = StructAnonAbbrev;
903       } else {
904         if (ST->isOpaque()) {
905           Code = bitc::TYPE_CODE_OPAQUE;
906         } else {
907           Code = bitc::TYPE_CODE_STRUCT_NAMED;
908           AbbrevToUse = StructNamedAbbrev;
909         }
910 
911         // Emit the name if it is present.
912         if (!ST->getName().empty())
913           writeStringRecord(Stream, bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
914                             StructNameAbbrev);
915       }
916       break;
917     }
918     case Type::ArrayTyID: {
919       ArrayType *AT = cast<ArrayType>(T);
920       // ARRAY: [numelts, eltty]
921       Code = bitc::TYPE_CODE_ARRAY;
922       TypeVals.push_back(AT->getNumElements());
923       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
924       AbbrevToUse = ArrayAbbrev;
925       break;
926     }
927     case Type::VectorTyID: {
928       VectorType *VT = cast<VectorType>(T);
929       // VECTOR [numelts, eltty]
930       Code = bitc::TYPE_CODE_VECTOR;
931       TypeVals.push_back(VT->getNumElements());
932       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
933       break;
934     }
935     }
936 
937     // Emit the finished record.
938     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
939     TypeVals.clear();
940   }
941 
942   Stream.ExitBlock();
943 }
944 
945 static unsigned getEncodedLinkage(const GlobalValue::LinkageTypes Linkage) {
946   switch (Linkage) {
947   case GlobalValue::ExternalLinkage:
948     return 0;
949   case GlobalValue::WeakAnyLinkage:
950     return 16;
951   case GlobalValue::AppendingLinkage:
952     return 2;
953   case GlobalValue::InternalLinkage:
954     return 3;
955   case GlobalValue::LinkOnceAnyLinkage:
956     return 18;
957   case GlobalValue::ExternalWeakLinkage:
958     return 7;
959   case GlobalValue::CommonLinkage:
960     return 8;
961   case GlobalValue::PrivateLinkage:
962     return 9;
963   case GlobalValue::WeakODRLinkage:
964     return 17;
965   case GlobalValue::LinkOnceODRLinkage:
966     return 19;
967   case GlobalValue::AvailableExternallyLinkage:
968     return 12;
969   }
970   llvm_unreachable("Invalid linkage");
971 }
972 
973 static unsigned getEncodedLinkage(const GlobalValue &GV) {
974   return getEncodedLinkage(GV.getLinkage());
975 }
976 
977 static uint64_t getEncodedFFlags(FunctionSummary::FFlags Flags) {
978   uint64_t RawFlags = 0;
979   RawFlags |= Flags.ReadNone;
980   RawFlags |= (Flags.ReadOnly << 1);
981   RawFlags |= (Flags.NoRecurse << 2);
982   RawFlags |= (Flags.ReturnDoesNotAlias << 3);
983   RawFlags |= (Flags.NoInline << 4);
984   return RawFlags;
985 }
986 
987 // Decode the flags for GlobalValue in the summary
988 static uint64_t getEncodedGVSummaryFlags(GlobalValueSummary::GVFlags Flags) {
989   uint64_t RawFlags = 0;
990 
991   RawFlags |= Flags.NotEligibleToImport; // bool
992   RawFlags |= (Flags.Live << 1);
993   RawFlags |= (Flags.DSOLocal << 2);
994 
995   // Linkage don't need to be remapped at that time for the summary. Any future
996   // change to the getEncodedLinkage() function will need to be taken into
997   // account here as well.
998   RawFlags = (RawFlags << 4) | Flags.Linkage; // 4 bits
999 
1000   return RawFlags;
1001 }
1002 
1003 static uint64_t getEncodedGVarFlags(GlobalVarSummary::GVarFlags Flags) {
1004   uint64_t RawFlags = Flags.ReadOnly;
1005   return RawFlags;
1006 }
1007 
1008 static unsigned getEncodedVisibility(const GlobalValue &GV) {
1009   switch (GV.getVisibility()) {
1010   case GlobalValue::DefaultVisibility:   return 0;
1011   case GlobalValue::HiddenVisibility:    return 1;
1012   case GlobalValue::ProtectedVisibility: return 2;
1013   }
1014   llvm_unreachable("Invalid visibility");
1015 }
1016 
1017 static unsigned getEncodedDLLStorageClass(const GlobalValue &GV) {
1018   switch (GV.getDLLStorageClass()) {
1019   case GlobalValue::DefaultStorageClass:   return 0;
1020   case GlobalValue::DLLImportStorageClass: return 1;
1021   case GlobalValue::DLLExportStorageClass: return 2;
1022   }
1023   llvm_unreachable("Invalid DLL storage class");
1024 }
1025 
1026 static unsigned getEncodedThreadLocalMode(const GlobalValue &GV) {
1027   switch (GV.getThreadLocalMode()) {
1028     case GlobalVariable::NotThreadLocal:         return 0;
1029     case GlobalVariable::GeneralDynamicTLSModel: return 1;
1030     case GlobalVariable::LocalDynamicTLSModel:   return 2;
1031     case GlobalVariable::InitialExecTLSModel:    return 3;
1032     case GlobalVariable::LocalExecTLSModel:      return 4;
1033   }
1034   llvm_unreachable("Invalid TLS model");
1035 }
1036 
1037 static unsigned getEncodedComdatSelectionKind(const Comdat &C) {
1038   switch (C.getSelectionKind()) {
1039   case Comdat::Any:
1040     return bitc::COMDAT_SELECTION_KIND_ANY;
1041   case Comdat::ExactMatch:
1042     return bitc::COMDAT_SELECTION_KIND_EXACT_MATCH;
1043   case Comdat::Largest:
1044     return bitc::COMDAT_SELECTION_KIND_LARGEST;
1045   case Comdat::NoDuplicates:
1046     return bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES;
1047   case Comdat::SameSize:
1048     return bitc::COMDAT_SELECTION_KIND_SAME_SIZE;
1049   }
1050   llvm_unreachable("Invalid selection kind");
1051 }
1052 
1053 static unsigned getEncodedUnnamedAddr(const GlobalValue &GV) {
1054   switch (GV.getUnnamedAddr()) {
1055   case GlobalValue::UnnamedAddr::None:   return 0;
1056   case GlobalValue::UnnamedAddr::Local:  return 2;
1057   case GlobalValue::UnnamedAddr::Global: return 1;
1058   }
1059   llvm_unreachable("Invalid unnamed_addr");
1060 }
1061 
1062 size_t ModuleBitcodeWriter::addToStrtab(StringRef Str) {
1063   if (GenerateHash)
1064     Hasher.update(Str);
1065   return StrtabBuilder.add(Str);
1066 }
1067 
1068 void ModuleBitcodeWriter::writeComdats() {
1069   SmallVector<unsigned, 64> Vals;
1070   for (const Comdat *C : VE.getComdats()) {
1071     // COMDAT: [strtab offset, strtab size, selection_kind]
1072     Vals.push_back(addToStrtab(C->getName()));
1073     Vals.push_back(C->getName().size());
1074     Vals.push_back(getEncodedComdatSelectionKind(*C));
1075     Stream.EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
1076     Vals.clear();
1077   }
1078 }
1079 
1080 /// Write a record that will eventually hold the word offset of the
1081 /// module-level VST. For now the offset is 0, which will be backpatched
1082 /// after the real VST is written. Saves the bit offset to backpatch.
1083 void ModuleBitcodeWriter::writeValueSymbolTableForwardDecl() {
1084   // Write a placeholder value in for the offset of the real VST,
1085   // which is written after the function blocks so that it can include
1086   // the offset of each function. The placeholder offset will be
1087   // updated when the real VST is written.
1088   auto Abbv = std::make_shared<BitCodeAbbrev>();
1089   Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_VSTOFFSET));
1090   // Blocks are 32-bit aligned, so we can use a 32-bit word offset to
1091   // hold the real VST offset. Must use fixed instead of VBR as we don't
1092   // know how many VBR chunks to reserve ahead of time.
1093   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
1094   unsigned VSTOffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1095 
1096   // Emit the placeholder
1097   uint64_t Vals[] = {bitc::MODULE_CODE_VSTOFFSET, 0};
1098   Stream.EmitRecordWithAbbrev(VSTOffsetAbbrev, Vals);
1099 
1100   // Compute and save the bit offset to the placeholder, which will be
1101   // patched when the real VST is written. We can simply subtract the 32-bit
1102   // fixed size from the current bit number to get the location to backpatch.
1103   VSTOffsetPlaceholder = Stream.GetCurrentBitNo() - 32;
1104 }
1105 
1106 enum StringEncoding { SE_Char6, SE_Fixed7, SE_Fixed8 };
1107 
1108 /// Determine the encoding to use for the given string name and length.
1109 static StringEncoding getStringEncoding(StringRef Str) {
1110   bool isChar6 = true;
1111   for (char C : Str) {
1112     if (isChar6)
1113       isChar6 = BitCodeAbbrevOp::isChar6(C);
1114     if ((unsigned char)C & 128)
1115       // don't bother scanning the rest.
1116       return SE_Fixed8;
1117   }
1118   if (isChar6)
1119     return SE_Char6;
1120   return SE_Fixed7;
1121 }
1122 
1123 /// Emit top-level description of module, including target triple, inline asm,
1124 /// descriptors for global variables, and function prototype info.
1125 /// Returns the bit offset to backpatch with the location of the real VST.
1126 void ModuleBitcodeWriter::writeModuleInfo() {
1127   // Emit various pieces of data attached to a module.
1128   if (!M.getTargetTriple().empty())
1129     writeStringRecord(Stream, bitc::MODULE_CODE_TRIPLE, M.getTargetTriple(),
1130                       0 /*TODO*/);
1131   const std::string &DL = M.getDataLayoutStr();
1132   if (!DL.empty())
1133     writeStringRecord(Stream, bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/);
1134   if (!M.getModuleInlineAsm().empty())
1135     writeStringRecord(Stream, bitc::MODULE_CODE_ASM, M.getModuleInlineAsm(),
1136                       0 /*TODO*/);
1137 
1138   // Emit information about sections and GC, computing how many there are. Also
1139   // compute the maximum alignment value.
1140   std::map<std::string, unsigned> SectionMap;
1141   std::map<std::string, unsigned> GCMap;
1142   unsigned MaxAlignment = 0;
1143   unsigned MaxGlobalType = 0;
1144   for (const GlobalValue &GV : M.globals()) {
1145     MaxAlignment = std::max(MaxAlignment, GV.getAlignment());
1146     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getValueType()));
1147     if (GV.hasSection()) {
1148       // Give section names unique ID's.
1149       unsigned &Entry = SectionMap[GV.getSection()];
1150       if (!Entry) {
1151         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
1152                           0 /*TODO*/);
1153         Entry = SectionMap.size();
1154       }
1155     }
1156   }
1157   for (const Function &F : M) {
1158     MaxAlignment = std::max(MaxAlignment, F.getAlignment());
1159     if (F.hasSection()) {
1160       // Give section names unique ID's.
1161       unsigned &Entry = SectionMap[F.getSection()];
1162       if (!Entry) {
1163         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
1164                           0 /*TODO*/);
1165         Entry = SectionMap.size();
1166       }
1167     }
1168     if (F.hasGC()) {
1169       // Same for GC names.
1170       unsigned &Entry = GCMap[F.getGC()];
1171       if (!Entry) {
1172         writeStringRecord(Stream, bitc::MODULE_CODE_GCNAME, F.getGC(),
1173                           0 /*TODO*/);
1174         Entry = GCMap.size();
1175       }
1176     }
1177   }
1178 
1179   // Emit abbrev for globals, now that we know # sections and max alignment.
1180   unsigned SimpleGVarAbbrev = 0;
1181   if (!M.global_empty()) {
1182     // Add an abbrev for common globals with no visibility or thread localness.
1183     auto Abbv = std::make_shared<BitCodeAbbrev>();
1184     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
1185     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1186     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1187     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1188                               Log2_32_Ceil(MaxGlobalType+1)));
1189     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddrSpace << 2
1190                                                            //| explicitType << 1
1191                                                            //| constant
1192     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Initializer.
1193     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // Linkage.
1194     if (MaxAlignment == 0)                                 // Alignment.
1195       Abbv->Add(BitCodeAbbrevOp(0));
1196     else {
1197       unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
1198       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1199                                Log2_32_Ceil(MaxEncAlignment+1)));
1200     }
1201     if (SectionMap.empty())                                    // Section.
1202       Abbv->Add(BitCodeAbbrevOp(0));
1203     else
1204       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1205                                Log2_32_Ceil(SectionMap.size()+1)));
1206     // Don't bother emitting vis + thread local.
1207     SimpleGVarAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1208   }
1209 
1210   SmallVector<unsigned, 64> Vals;
1211   // Emit the module's source file name.
1212   {
1213     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
1214     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
1215     if (Bits == SE_Char6)
1216       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
1217     else if (Bits == SE_Fixed7)
1218       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
1219 
1220     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
1221     auto Abbv = std::make_shared<BitCodeAbbrev>();
1222     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
1223     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1224     Abbv->Add(AbbrevOpToUse);
1225     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1226 
1227     for (const auto P : M.getSourceFileName())
1228       Vals.push_back((unsigned char)P);
1229 
1230     // Emit the finished record.
1231     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
1232     Vals.clear();
1233   }
1234 
1235   // Emit the global variable information.
1236   for (const GlobalVariable &GV : M.globals()) {
1237     unsigned AbbrevToUse = 0;
1238 
1239     // GLOBALVAR: [strtab offset, strtab size, type, isconst, initid,
1240     //             linkage, alignment, section, visibility, threadlocal,
1241     //             unnamed_addr, externally_initialized, dllstorageclass,
1242     //             comdat, attributes, DSO_Local]
1243     Vals.push_back(addToStrtab(GV.getName()));
1244     Vals.push_back(GV.getName().size());
1245     Vals.push_back(VE.getTypeID(GV.getValueType()));
1246     Vals.push_back(GV.getType()->getAddressSpace() << 2 | 2 | GV.isConstant());
1247     Vals.push_back(GV.isDeclaration() ? 0 :
1248                    (VE.getValueID(GV.getInitializer()) + 1));
1249     Vals.push_back(getEncodedLinkage(GV));
1250     Vals.push_back(Log2_32(GV.getAlignment())+1);
1251     Vals.push_back(GV.hasSection() ? SectionMap[GV.getSection()] : 0);
1252     if (GV.isThreadLocal() ||
1253         GV.getVisibility() != GlobalValue::DefaultVisibility ||
1254         GV.getUnnamedAddr() != GlobalValue::UnnamedAddr::None ||
1255         GV.isExternallyInitialized() ||
1256         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
1257         GV.hasComdat() ||
1258         GV.hasAttributes() ||
1259         GV.isDSOLocal()) {
1260       Vals.push_back(getEncodedVisibility(GV));
1261       Vals.push_back(getEncodedThreadLocalMode(GV));
1262       Vals.push_back(getEncodedUnnamedAddr(GV));
1263       Vals.push_back(GV.isExternallyInitialized());
1264       Vals.push_back(getEncodedDLLStorageClass(GV));
1265       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
1266 
1267       auto AL = GV.getAttributesAsList(AttributeList::FunctionIndex);
1268       Vals.push_back(VE.getAttributeListID(AL));
1269 
1270       Vals.push_back(GV.isDSOLocal());
1271     } else {
1272       AbbrevToUse = SimpleGVarAbbrev;
1273     }
1274 
1275     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
1276     Vals.clear();
1277   }
1278 
1279   // Emit the function proto information.
1280   for (const Function &F : M) {
1281     // FUNCTION:  [strtab offset, strtab size, type, callingconv, isproto,
1282     //             linkage, paramattrs, alignment, section, visibility, gc,
1283     //             unnamed_addr, prologuedata, dllstorageclass, comdat,
1284     //             prefixdata, personalityfn, DSO_Local, addrspace]
1285     Vals.push_back(addToStrtab(F.getName()));
1286     Vals.push_back(F.getName().size());
1287     Vals.push_back(VE.getTypeID(F.getFunctionType()));
1288     Vals.push_back(F.getCallingConv());
1289     Vals.push_back(F.isDeclaration());
1290     Vals.push_back(getEncodedLinkage(F));
1291     Vals.push_back(VE.getAttributeListID(F.getAttributes()));
1292     Vals.push_back(Log2_32(F.getAlignment())+1);
1293     Vals.push_back(F.hasSection() ? SectionMap[F.getSection()] : 0);
1294     Vals.push_back(getEncodedVisibility(F));
1295     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
1296     Vals.push_back(getEncodedUnnamedAddr(F));
1297     Vals.push_back(F.hasPrologueData() ? (VE.getValueID(F.getPrologueData()) + 1)
1298                                        : 0);
1299     Vals.push_back(getEncodedDLLStorageClass(F));
1300     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
1301     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
1302                                      : 0);
1303     Vals.push_back(
1304         F.hasPersonalityFn() ? (VE.getValueID(F.getPersonalityFn()) + 1) : 0);
1305 
1306     Vals.push_back(F.isDSOLocal());
1307     Vals.push_back(F.getAddressSpace());
1308 
1309     unsigned AbbrevToUse = 0;
1310     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
1311     Vals.clear();
1312   }
1313 
1314   // Emit the alias information.
1315   for (const GlobalAlias &A : M.aliases()) {
1316     // ALIAS: [strtab offset, strtab size, alias type, aliasee val#, linkage,
1317     //         visibility, dllstorageclass, threadlocal, unnamed_addr,
1318     //         DSO_Local]
1319     Vals.push_back(addToStrtab(A.getName()));
1320     Vals.push_back(A.getName().size());
1321     Vals.push_back(VE.getTypeID(A.getValueType()));
1322     Vals.push_back(A.getType()->getAddressSpace());
1323     Vals.push_back(VE.getValueID(A.getAliasee()));
1324     Vals.push_back(getEncodedLinkage(A));
1325     Vals.push_back(getEncodedVisibility(A));
1326     Vals.push_back(getEncodedDLLStorageClass(A));
1327     Vals.push_back(getEncodedThreadLocalMode(A));
1328     Vals.push_back(getEncodedUnnamedAddr(A));
1329     Vals.push_back(A.isDSOLocal());
1330 
1331     unsigned AbbrevToUse = 0;
1332     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
1333     Vals.clear();
1334   }
1335 
1336   // Emit the ifunc information.
1337   for (const GlobalIFunc &I : M.ifuncs()) {
1338     // IFUNC: [strtab offset, strtab size, ifunc type, address space, resolver
1339     //         val#, linkage, visibility, DSO_Local]
1340     Vals.push_back(addToStrtab(I.getName()));
1341     Vals.push_back(I.getName().size());
1342     Vals.push_back(VE.getTypeID(I.getValueType()));
1343     Vals.push_back(I.getType()->getAddressSpace());
1344     Vals.push_back(VE.getValueID(I.getResolver()));
1345     Vals.push_back(getEncodedLinkage(I));
1346     Vals.push_back(getEncodedVisibility(I));
1347     Vals.push_back(I.isDSOLocal());
1348     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
1349     Vals.clear();
1350   }
1351 
1352   writeValueSymbolTableForwardDecl();
1353 }
1354 
1355 static uint64_t getOptimizationFlags(const Value *V) {
1356   uint64_t Flags = 0;
1357 
1358   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
1359     if (OBO->hasNoSignedWrap())
1360       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
1361     if (OBO->hasNoUnsignedWrap())
1362       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
1363   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
1364     if (PEO->isExact())
1365       Flags |= 1 << bitc::PEO_EXACT;
1366   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
1367     if (FPMO->hasAllowReassoc())
1368       Flags |= bitc::AllowReassoc;
1369     if (FPMO->hasNoNaNs())
1370       Flags |= bitc::NoNaNs;
1371     if (FPMO->hasNoInfs())
1372       Flags |= bitc::NoInfs;
1373     if (FPMO->hasNoSignedZeros())
1374       Flags |= bitc::NoSignedZeros;
1375     if (FPMO->hasAllowReciprocal())
1376       Flags |= bitc::AllowReciprocal;
1377     if (FPMO->hasAllowContract())
1378       Flags |= bitc::AllowContract;
1379     if (FPMO->hasApproxFunc())
1380       Flags |= bitc::ApproxFunc;
1381   }
1382 
1383   return Flags;
1384 }
1385 
1386 void ModuleBitcodeWriter::writeValueAsMetadata(
1387     const ValueAsMetadata *MD, SmallVectorImpl<uint64_t> &Record) {
1388   // Mimic an MDNode with a value as one operand.
1389   Value *V = MD->getValue();
1390   Record.push_back(VE.getTypeID(V->getType()));
1391   Record.push_back(VE.getValueID(V));
1392   Stream.EmitRecord(bitc::METADATA_VALUE, Record, 0);
1393   Record.clear();
1394 }
1395 
1396 void ModuleBitcodeWriter::writeMDTuple(const MDTuple *N,
1397                                        SmallVectorImpl<uint64_t> &Record,
1398                                        unsigned Abbrev) {
1399   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
1400     Metadata *MD = N->getOperand(i);
1401     assert(!(MD && isa<LocalAsMetadata>(MD)) &&
1402            "Unexpected function-local metadata");
1403     Record.push_back(VE.getMetadataOrNullID(MD));
1404   }
1405   Stream.EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
1406                                     : bitc::METADATA_NODE,
1407                     Record, Abbrev);
1408   Record.clear();
1409 }
1410 
1411 unsigned ModuleBitcodeWriter::createDILocationAbbrev() {
1412   // Assume the column is usually under 128, and always output the inlined-at
1413   // location (it's never more expensive than building an array size 1).
1414   auto Abbv = std::make_shared<BitCodeAbbrev>();
1415   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
1416   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1417   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1418   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1419   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1420   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1421   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1422   return Stream.EmitAbbrev(std::move(Abbv));
1423 }
1424 
1425 void ModuleBitcodeWriter::writeDILocation(const DILocation *N,
1426                                           SmallVectorImpl<uint64_t> &Record,
1427                                           unsigned &Abbrev) {
1428   if (!Abbrev)
1429     Abbrev = createDILocationAbbrev();
1430 
1431   Record.push_back(N->isDistinct());
1432   Record.push_back(N->getLine());
1433   Record.push_back(N->getColumn());
1434   Record.push_back(VE.getMetadataID(N->getScope()));
1435   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
1436   Record.push_back(N->isImplicitCode());
1437 
1438   Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
1439   Record.clear();
1440 }
1441 
1442 unsigned ModuleBitcodeWriter::createGenericDINodeAbbrev() {
1443   // Assume the column is usually under 128, and always output the inlined-at
1444   // location (it's never more expensive than building an array size 1).
1445   auto Abbv = std::make_shared<BitCodeAbbrev>();
1446   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
1447   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1448   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1449   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1450   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1451   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1452   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1453   return Stream.EmitAbbrev(std::move(Abbv));
1454 }
1455 
1456 void ModuleBitcodeWriter::writeGenericDINode(const GenericDINode *N,
1457                                              SmallVectorImpl<uint64_t> &Record,
1458                                              unsigned &Abbrev) {
1459   if (!Abbrev)
1460     Abbrev = createGenericDINodeAbbrev();
1461 
1462   Record.push_back(N->isDistinct());
1463   Record.push_back(N->getTag());
1464   Record.push_back(0); // Per-tag version field; unused for now.
1465 
1466   for (auto &I : N->operands())
1467     Record.push_back(VE.getMetadataOrNullID(I));
1468 
1469   Stream.EmitRecord(bitc::METADATA_GENERIC_DEBUG, Record, Abbrev);
1470   Record.clear();
1471 }
1472 
1473 static uint64_t rotateSign(int64_t I) {
1474   uint64_t U = I;
1475   return I < 0 ? ~(U << 1) : U << 1;
1476 }
1477 
1478 void ModuleBitcodeWriter::writeDISubrange(const DISubrange *N,
1479                                           SmallVectorImpl<uint64_t> &Record,
1480                                           unsigned Abbrev) {
1481   const uint64_t Version = 1 << 1;
1482   Record.push_back((uint64_t)N->isDistinct() | Version);
1483   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1484   Record.push_back(rotateSign(N->getLowerBound()));
1485 
1486   Stream.EmitRecord(bitc::METADATA_SUBRANGE, Record, Abbrev);
1487   Record.clear();
1488 }
1489 
1490 void ModuleBitcodeWriter::writeDIEnumerator(const DIEnumerator *N,
1491                                             SmallVectorImpl<uint64_t> &Record,
1492                                             unsigned Abbrev) {
1493   Record.push_back((N->isUnsigned() << 1) | N->isDistinct());
1494   Record.push_back(rotateSign(N->getValue()));
1495   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1496 
1497   Stream.EmitRecord(bitc::METADATA_ENUMERATOR, Record, Abbrev);
1498   Record.clear();
1499 }
1500 
1501 void ModuleBitcodeWriter::writeDIBasicType(const DIBasicType *N,
1502                                            SmallVectorImpl<uint64_t> &Record,
1503                                            unsigned Abbrev) {
1504   Record.push_back(N->isDistinct());
1505   Record.push_back(N->getTag());
1506   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1507   Record.push_back(N->getSizeInBits());
1508   Record.push_back(N->getAlignInBits());
1509   Record.push_back(N->getEncoding());
1510   Record.push_back(N->getFlags());
1511 
1512   Stream.EmitRecord(bitc::METADATA_BASIC_TYPE, Record, Abbrev);
1513   Record.clear();
1514 }
1515 
1516 void ModuleBitcodeWriter::writeDIDerivedType(const DIDerivedType *N,
1517                                              SmallVectorImpl<uint64_t> &Record,
1518                                              unsigned Abbrev) {
1519   Record.push_back(N->isDistinct());
1520   Record.push_back(N->getTag());
1521   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1522   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1523   Record.push_back(N->getLine());
1524   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1525   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1526   Record.push_back(N->getSizeInBits());
1527   Record.push_back(N->getAlignInBits());
1528   Record.push_back(N->getOffsetInBits());
1529   Record.push_back(N->getFlags());
1530   Record.push_back(VE.getMetadataOrNullID(N->getExtraData()));
1531 
1532   // DWARF address space is encoded as N->getDWARFAddressSpace() + 1. 0 means
1533   // that there is no DWARF address space associated with DIDerivedType.
1534   if (const auto &DWARFAddressSpace = N->getDWARFAddressSpace())
1535     Record.push_back(*DWARFAddressSpace + 1);
1536   else
1537     Record.push_back(0);
1538 
1539   Stream.EmitRecord(bitc::METADATA_DERIVED_TYPE, Record, Abbrev);
1540   Record.clear();
1541 }
1542 
1543 void ModuleBitcodeWriter::writeDICompositeType(
1544     const DICompositeType *N, SmallVectorImpl<uint64_t> &Record,
1545     unsigned Abbrev) {
1546   const unsigned IsNotUsedInOldTypeRef = 0x2;
1547   Record.push_back(IsNotUsedInOldTypeRef | (unsigned)N->isDistinct());
1548   Record.push_back(N->getTag());
1549   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1550   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1551   Record.push_back(N->getLine());
1552   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1553   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1554   Record.push_back(N->getSizeInBits());
1555   Record.push_back(N->getAlignInBits());
1556   Record.push_back(N->getOffsetInBits());
1557   Record.push_back(N->getFlags());
1558   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1559   Record.push_back(N->getRuntimeLang());
1560   Record.push_back(VE.getMetadataOrNullID(N->getVTableHolder()));
1561   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1562   Record.push_back(VE.getMetadataOrNullID(N->getRawIdentifier()));
1563   Record.push_back(VE.getMetadataOrNullID(N->getDiscriminator()));
1564 
1565   Stream.EmitRecord(bitc::METADATA_COMPOSITE_TYPE, Record, Abbrev);
1566   Record.clear();
1567 }
1568 
1569 void ModuleBitcodeWriter::writeDISubroutineType(
1570     const DISubroutineType *N, SmallVectorImpl<uint64_t> &Record,
1571     unsigned Abbrev) {
1572   const unsigned HasNoOldTypeRefs = 0x2;
1573   Record.push_back(HasNoOldTypeRefs | (unsigned)N->isDistinct());
1574   Record.push_back(N->getFlags());
1575   Record.push_back(VE.getMetadataOrNullID(N->getTypeArray().get()));
1576   Record.push_back(N->getCC());
1577 
1578   Stream.EmitRecord(bitc::METADATA_SUBROUTINE_TYPE, Record, Abbrev);
1579   Record.clear();
1580 }
1581 
1582 void ModuleBitcodeWriter::writeDIFile(const DIFile *N,
1583                                       SmallVectorImpl<uint64_t> &Record,
1584                                       unsigned Abbrev) {
1585   Record.push_back(N->isDistinct());
1586   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
1587   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
1588   if (N->getRawChecksum()) {
1589     Record.push_back(N->getRawChecksum()->Kind);
1590     Record.push_back(VE.getMetadataOrNullID(N->getRawChecksum()->Value));
1591   } else {
1592     // Maintain backwards compatibility with the old internal representation of
1593     // CSK_None in ChecksumKind by writing nulls here when Checksum is None.
1594     Record.push_back(0);
1595     Record.push_back(VE.getMetadataOrNullID(nullptr));
1596   }
1597   auto Source = N->getRawSource();
1598   if (Source)
1599     Record.push_back(VE.getMetadataOrNullID(*Source));
1600 
1601   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
1602   Record.clear();
1603 }
1604 
1605 void ModuleBitcodeWriter::writeDICompileUnit(const DICompileUnit *N,
1606                                              SmallVectorImpl<uint64_t> &Record,
1607                                              unsigned Abbrev) {
1608   assert(N->isDistinct() && "Expected distinct compile units");
1609   Record.push_back(/* IsDistinct */ true);
1610   Record.push_back(N->getSourceLanguage());
1611   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1612   Record.push_back(VE.getMetadataOrNullID(N->getRawProducer()));
1613   Record.push_back(N->isOptimized());
1614   Record.push_back(VE.getMetadataOrNullID(N->getRawFlags()));
1615   Record.push_back(N->getRuntimeVersion());
1616   Record.push_back(VE.getMetadataOrNullID(N->getRawSplitDebugFilename()));
1617   Record.push_back(N->getEmissionKind());
1618   Record.push_back(VE.getMetadataOrNullID(N->getEnumTypes().get()));
1619   Record.push_back(VE.getMetadataOrNullID(N->getRetainedTypes().get()));
1620   Record.push_back(/* subprograms */ 0);
1621   Record.push_back(VE.getMetadataOrNullID(N->getGlobalVariables().get()));
1622   Record.push_back(VE.getMetadataOrNullID(N->getImportedEntities().get()));
1623   Record.push_back(N->getDWOId());
1624   Record.push_back(VE.getMetadataOrNullID(N->getMacros().get()));
1625   Record.push_back(N->getSplitDebugInlining());
1626   Record.push_back(N->getDebugInfoForProfiling());
1627   Record.push_back((unsigned)N->getNameTableKind());
1628 
1629   Stream.EmitRecord(bitc::METADATA_COMPILE_UNIT, Record, Abbrev);
1630   Record.clear();
1631 }
1632 
1633 void ModuleBitcodeWriter::writeDISubprogram(const DISubprogram *N,
1634                                             SmallVectorImpl<uint64_t> &Record,
1635                                             unsigned Abbrev) {
1636   uint64_t HasUnitFlag = 1 << 1;
1637   Record.push_back(N->isDistinct() | HasUnitFlag);
1638   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1639   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1640   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1641   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1642   Record.push_back(N->getLine());
1643   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1644   Record.push_back(N->isLocalToUnit());
1645   Record.push_back(N->isDefinition());
1646   Record.push_back(N->getScopeLine());
1647   Record.push_back(VE.getMetadataOrNullID(N->getContainingType()));
1648   Record.push_back(N->getVirtuality());
1649   Record.push_back(N->getVirtualIndex());
1650   Record.push_back(N->getFlags());
1651   Record.push_back(N->isOptimized());
1652   Record.push_back(VE.getMetadataOrNullID(N->getRawUnit()));
1653   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1654   Record.push_back(VE.getMetadataOrNullID(N->getDeclaration()));
1655   Record.push_back(VE.getMetadataOrNullID(N->getRetainedNodes().get()));
1656   Record.push_back(N->getThisAdjustment());
1657   Record.push_back(VE.getMetadataOrNullID(N->getThrownTypes().get()));
1658 
1659   Stream.EmitRecord(bitc::METADATA_SUBPROGRAM, Record, Abbrev);
1660   Record.clear();
1661 }
1662 
1663 void ModuleBitcodeWriter::writeDILexicalBlock(const DILexicalBlock *N,
1664                                               SmallVectorImpl<uint64_t> &Record,
1665                                               unsigned Abbrev) {
1666   Record.push_back(N->isDistinct());
1667   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1668   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1669   Record.push_back(N->getLine());
1670   Record.push_back(N->getColumn());
1671 
1672   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK, Record, Abbrev);
1673   Record.clear();
1674 }
1675 
1676 void ModuleBitcodeWriter::writeDILexicalBlockFile(
1677     const DILexicalBlockFile *N, SmallVectorImpl<uint64_t> &Record,
1678     unsigned Abbrev) {
1679   Record.push_back(N->isDistinct());
1680   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1681   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1682   Record.push_back(N->getDiscriminator());
1683 
1684   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK_FILE, Record, Abbrev);
1685   Record.clear();
1686 }
1687 
1688 void ModuleBitcodeWriter::writeDINamespace(const DINamespace *N,
1689                                            SmallVectorImpl<uint64_t> &Record,
1690                                            unsigned Abbrev) {
1691   Record.push_back(N->isDistinct() | N->getExportSymbols() << 1);
1692   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1693   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1694 
1695   Stream.EmitRecord(bitc::METADATA_NAMESPACE, Record, Abbrev);
1696   Record.clear();
1697 }
1698 
1699 void ModuleBitcodeWriter::writeDIMacro(const DIMacro *N,
1700                                        SmallVectorImpl<uint64_t> &Record,
1701                                        unsigned Abbrev) {
1702   Record.push_back(N->isDistinct());
1703   Record.push_back(N->getMacinfoType());
1704   Record.push_back(N->getLine());
1705   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1706   Record.push_back(VE.getMetadataOrNullID(N->getRawValue()));
1707 
1708   Stream.EmitRecord(bitc::METADATA_MACRO, Record, Abbrev);
1709   Record.clear();
1710 }
1711 
1712 void ModuleBitcodeWriter::writeDIMacroFile(const DIMacroFile *N,
1713                                            SmallVectorImpl<uint64_t> &Record,
1714                                            unsigned Abbrev) {
1715   Record.push_back(N->isDistinct());
1716   Record.push_back(N->getMacinfoType());
1717   Record.push_back(N->getLine());
1718   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1719   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1720 
1721   Stream.EmitRecord(bitc::METADATA_MACRO_FILE, Record, Abbrev);
1722   Record.clear();
1723 }
1724 
1725 void ModuleBitcodeWriter::writeDIModule(const DIModule *N,
1726                                         SmallVectorImpl<uint64_t> &Record,
1727                                         unsigned Abbrev) {
1728   Record.push_back(N->isDistinct());
1729   for (auto &I : N->operands())
1730     Record.push_back(VE.getMetadataOrNullID(I));
1731 
1732   Stream.EmitRecord(bitc::METADATA_MODULE, Record, Abbrev);
1733   Record.clear();
1734 }
1735 
1736 void ModuleBitcodeWriter::writeDITemplateTypeParameter(
1737     const DITemplateTypeParameter *N, SmallVectorImpl<uint64_t> &Record,
1738     unsigned Abbrev) {
1739   Record.push_back(N->isDistinct());
1740   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1741   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1742 
1743   Stream.EmitRecord(bitc::METADATA_TEMPLATE_TYPE, Record, Abbrev);
1744   Record.clear();
1745 }
1746 
1747 void ModuleBitcodeWriter::writeDITemplateValueParameter(
1748     const DITemplateValueParameter *N, SmallVectorImpl<uint64_t> &Record,
1749     unsigned Abbrev) {
1750   Record.push_back(N->isDistinct());
1751   Record.push_back(N->getTag());
1752   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1753   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1754   Record.push_back(VE.getMetadataOrNullID(N->getValue()));
1755 
1756   Stream.EmitRecord(bitc::METADATA_TEMPLATE_VALUE, Record, Abbrev);
1757   Record.clear();
1758 }
1759 
1760 void ModuleBitcodeWriter::writeDIGlobalVariable(
1761     const DIGlobalVariable *N, SmallVectorImpl<uint64_t> &Record,
1762     unsigned Abbrev) {
1763   const uint64_t Version = 2 << 1;
1764   Record.push_back((uint64_t)N->isDistinct() | Version);
1765   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1766   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1767   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1768   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1769   Record.push_back(N->getLine());
1770   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1771   Record.push_back(N->isLocalToUnit());
1772   Record.push_back(N->isDefinition());
1773   Record.push_back(VE.getMetadataOrNullID(N->getStaticDataMemberDeclaration()));
1774   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams()));
1775   Record.push_back(N->getAlignInBits());
1776 
1777   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR, Record, Abbrev);
1778   Record.clear();
1779 }
1780 
1781 void ModuleBitcodeWriter::writeDILocalVariable(
1782     const DILocalVariable *N, SmallVectorImpl<uint64_t> &Record,
1783     unsigned Abbrev) {
1784   // In order to support all possible bitcode formats in BitcodeReader we need
1785   // to distinguish the following cases:
1786   // 1) Record has no artificial tag (Record[1]),
1787   //   has no obsolete inlinedAt field (Record[9]).
1788   //   In this case Record size will be 8, HasAlignment flag is false.
1789   // 2) Record has artificial tag (Record[1]),
1790   //   has no obsolete inlignedAt field (Record[9]).
1791   //   In this case Record size will be 9, HasAlignment flag is false.
1792   // 3) Record has both artificial tag (Record[1]) and
1793   //   obsolete inlignedAt field (Record[9]).
1794   //   In this case Record size will be 10, HasAlignment flag is false.
1795   // 4) Record has neither artificial tag, nor inlignedAt field, but
1796   //   HasAlignment flag is true and Record[8] contains alignment value.
1797   const uint64_t HasAlignmentFlag = 1 << 1;
1798   Record.push_back((uint64_t)N->isDistinct() | HasAlignmentFlag);
1799   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1800   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1801   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1802   Record.push_back(N->getLine());
1803   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1804   Record.push_back(N->getArg());
1805   Record.push_back(N->getFlags());
1806   Record.push_back(N->getAlignInBits());
1807 
1808   Stream.EmitRecord(bitc::METADATA_LOCAL_VAR, Record, Abbrev);
1809   Record.clear();
1810 }
1811 
1812 void ModuleBitcodeWriter::writeDILabel(
1813     const DILabel *N, SmallVectorImpl<uint64_t> &Record,
1814     unsigned Abbrev) {
1815   Record.push_back((uint64_t)N->isDistinct());
1816   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1817   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1818   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1819   Record.push_back(N->getLine());
1820 
1821   Stream.EmitRecord(bitc::METADATA_LABEL, Record, Abbrev);
1822   Record.clear();
1823 }
1824 
1825 void ModuleBitcodeWriter::writeDIExpression(const DIExpression *N,
1826                                             SmallVectorImpl<uint64_t> &Record,
1827                                             unsigned Abbrev) {
1828   Record.reserve(N->getElements().size() + 1);
1829   const uint64_t Version = 3 << 1;
1830   Record.push_back((uint64_t)N->isDistinct() | Version);
1831   Record.append(N->elements_begin(), N->elements_end());
1832 
1833   Stream.EmitRecord(bitc::METADATA_EXPRESSION, Record, Abbrev);
1834   Record.clear();
1835 }
1836 
1837 void ModuleBitcodeWriter::writeDIGlobalVariableExpression(
1838     const DIGlobalVariableExpression *N, SmallVectorImpl<uint64_t> &Record,
1839     unsigned Abbrev) {
1840   Record.push_back(N->isDistinct());
1841   Record.push_back(VE.getMetadataOrNullID(N->getVariable()));
1842   Record.push_back(VE.getMetadataOrNullID(N->getExpression()));
1843 
1844   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR_EXPR, Record, Abbrev);
1845   Record.clear();
1846 }
1847 
1848 void ModuleBitcodeWriter::writeDIObjCProperty(const DIObjCProperty *N,
1849                                               SmallVectorImpl<uint64_t> &Record,
1850                                               unsigned Abbrev) {
1851   Record.push_back(N->isDistinct());
1852   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1853   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1854   Record.push_back(N->getLine());
1855   Record.push_back(VE.getMetadataOrNullID(N->getRawSetterName()));
1856   Record.push_back(VE.getMetadataOrNullID(N->getRawGetterName()));
1857   Record.push_back(N->getAttributes());
1858   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1859 
1860   Stream.EmitRecord(bitc::METADATA_OBJC_PROPERTY, Record, Abbrev);
1861   Record.clear();
1862 }
1863 
1864 void ModuleBitcodeWriter::writeDIImportedEntity(
1865     const DIImportedEntity *N, SmallVectorImpl<uint64_t> &Record,
1866     unsigned Abbrev) {
1867   Record.push_back(N->isDistinct());
1868   Record.push_back(N->getTag());
1869   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1870   Record.push_back(VE.getMetadataOrNullID(N->getEntity()));
1871   Record.push_back(N->getLine());
1872   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1873   Record.push_back(VE.getMetadataOrNullID(N->getRawFile()));
1874 
1875   Stream.EmitRecord(bitc::METADATA_IMPORTED_ENTITY, Record, Abbrev);
1876   Record.clear();
1877 }
1878 
1879 unsigned ModuleBitcodeWriter::createNamedMetadataAbbrev() {
1880   auto Abbv = std::make_shared<BitCodeAbbrev>();
1881   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
1882   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1883   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1884   return Stream.EmitAbbrev(std::move(Abbv));
1885 }
1886 
1887 void ModuleBitcodeWriter::writeNamedMetadata(
1888     SmallVectorImpl<uint64_t> &Record) {
1889   if (M.named_metadata_empty())
1890     return;
1891 
1892   unsigned Abbrev = createNamedMetadataAbbrev();
1893   for (const NamedMDNode &NMD : M.named_metadata()) {
1894     // Write name.
1895     StringRef Str = NMD.getName();
1896     Record.append(Str.bytes_begin(), Str.bytes_end());
1897     Stream.EmitRecord(bitc::METADATA_NAME, Record, Abbrev);
1898     Record.clear();
1899 
1900     // Write named metadata operands.
1901     for (const MDNode *N : NMD.operands())
1902       Record.push_back(VE.getMetadataID(N));
1903     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
1904     Record.clear();
1905   }
1906 }
1907 
1908 unsigned ModuleBitcodeWriter::createMetadataStringsAbbrev() {
1909   auto Abbv = std::make_shared<BitCodeAbbrev>();
1910   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRINGS));
1911   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // # of strings
1912   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // offset to chars
1913   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
1914   return Stream.EmitAbbrev(std::move(Abbv));
1915 }
1916 
1917 /// Write out a record for MDString.
1918 ///
1919 /// All the metadata strings in a metadata block are emitted in a single
1920 /// record.  The sizes and strings themselves are shoved into a blob.
1921 void ModuleBitcodeWriter::writeMetadataStrings(
1922     ArrayRef<const Metadata *> Strings, SmallVectorImpl<uint64_t> &Record) {
1923   if (Strings.empty())
1924     return;
1925 
1926   // Start the record with the number of strings.
1927   Record.push_back(bitc::METADATA_STRINGS);
1928   Record.push_back(Strings.size());
1929 
1930   // Emit the sizes of the strings in the blob.
1931   SmallString<256> Blob;
1932   {
1933     BitstreamWriter W(Blob);
1934     for (const Metadata *MD : Strings)
1935       W.EmitVBR(cast<MDString>(MD)->getLength(), 6);
1936     W.FlushToWord();
1937   }
1938 
1939   // Add the offset to the strings to the record.
1940   Record.push_back(Blob.size());
1941 
1942   // Add the strings to the blob.
1943   for (const Metadata *MD : Strings)
1944     Blob.append(cast<MDString>(MD)->getString());
1945 
1946   // Emit the final record.
1947   Stream.EmitRecordWithBlob(createMetadataStringsAbbrev(), Record, Blob);
1948   Record.clear();
1949 }
1950 
1951 // Generates an enum to use as an index in the Abbrev array of Metadata record.
1952 enum MetadataAbbrev : unsigned {
1953 #define HANDLE_MDNODE_LEAF(CLASS) CLASS##AbbrevID,
1954 #include "llvm/IR/Metadata.def"
1955   LastPlusOne
1956 };
1957 
1958 void ModuleBitcodeWriter::writeMetadataRecords(
1959     ArrayRef<const Metadata *> MDs, SmallVectorImpl<uint64_t> &Record,
1960     std::vector<unsigned> *MDAbbrevs, std::vector<uint64_t> *IndexPos) {
1961   if (MDs.empty())
1962     return;
1963 
1964   // Initialize MDNode abbreviations.
1965 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
1966 #include "llvm/IR/Metadata.def"
1967 
1968   for (const Metadata *MD : MDs) {
1969     if (IndexPos)
1970       IndexPos->push_back(Stream.GetCurrentBitNo());
1971     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
1972       assert(N->isResolved() && "Expected forward references to be resolved");
1973 
1974       switch (N->getMetadataID()) {
1975       default:
1976         llvm_unreachable("Invalid MDNode subclass");
1977 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
1978   case Metadata::CLASS##Kind:                                                  \
1979     if (MDAbbrevs)                                                             \
1980       write##CLASS(cast<CLASS>(N), Record,                                     \
1981                    (*MDAbbrevs)[MetadataAbbrev::CLASS##AbbrevID]);             \
1982     else                                                                       \
1983       write##CLASS(cast<CLASS>(N), Record, CLASS##Abbrev);                     \
1984     continue;
1985 #include "llvm/IR/Metadata.def"
1986       }
1987     }
1988     writeValueAsMetadata(cast<ValueAsMetadata>(MD), Record);
1989   }
1990 }
1991 
1992 void ModuleBitcodeWriter::writeModuleMetadata() {
1993   if (!VE.hasMDs() && M.named_metadata_empty())
1994     return;
1995 
1996   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 4);
1997   SmallVector<uint64_t, 64> Record;
1998 
1999   // Emit all abbrevs upfront, so that the reader can jump in the middle of the
2000   // block and load any metadata.
2001   std::vector<unsigned> MDAbbrevs;
2002 
2003   MDAbbrevs.resize(MetadataAbbrev::LastPlusOne);
2004   MDAbbrevs[MetadataAbbrev::DILocationAbbrevID] = createDILocationAbbrev();
2005   MDAbbrevs[MetadataAbbrev::GenericDINodeAbbrevID] =
2006       createGenericDINodeAbbrev();
2007 
2008   auto Abbv = std::make_shared<BitCodeAbbrev>();
2009   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX_OFFSET));
2010   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2011   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2012   unsigned OffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2013 
2014   Abbv = std::make_shared<BitCodeAbbrev>();
2015   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX));
2016   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2017   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2018   unsigned IndexAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2019 
2020   // Emit MDStrings together upfront.
2021   writeMetadataStrings(VE.getMDStrings(), Record);
2022 
2023   // We only emit an index for the metadata record if we have more than a given
2024   // (naive) threshold of metadatas, otherwise it is not worth it.
2025   if (VE.getNonMDStrings().size() > IndexThreshold) {
2026     // Write a placeholder value in for the offset of the metadata index,
2027     // which is written after the records, so that it can include
2028     // the offset of each entry. The placeholder offset will be
2029     // updated after all records are emitted.
2030     uint64_t Vals[] = {0, 0};
2031     Stream.EmitRecord(bitc::METADATA_INDEX_OFFSET, Vals, OffsetAbbrev);
2032   }
2033 
2034   // Compute and save the bit offset to the current position, which will be
2035   // patched when we emit the index later. We can simply subtract the 64-bit
2036   // fixed size from the current bit number to get the location to backpatch.
2037   uint64_t IndexOffsetRecordBitPos = Stream.GetCurrentBitNo();
2038 
2039   // This index will contain the bitpos for each individual record.
2040   std::vector<uint64_t> IndexPos;
2041   IndexPos.reserve(VE.getNonMDStrings().size());
2042 
2043   // Write all the records
2044   writeMetadataRecords(VE.getNonMDStrings(), Record, &MDAbbrevs, &IndexPos);
2045 
2046   if (VE.getNonMDStrings().size() > IndexThreshold) {
2047     // Now that we have emitted all the records we will emit the index. But
2048     // first
2049     // backpatch the forward reference so that the reader can skip the records
2050     // efficiently.
2051     Stream.BackpatchWord64(IndexOffsetRecordBitPos - 64,
2052                            Stream.GetCurrentBitNo() - IndexOffsetRecordBitPos);
2053 
2054     // Delta encode the index.
2055     uint64_t PreviousValue = IndexOffsetRecordBitPos;
2056     for (auto &Elt : IndexPos) {
2057       auto EltDelta = Elt - PreviousValue;
2058       PreviousValue = Elt;
2059       Elt = EltDelta;
2060     }
2061     // Emit the index record.
2062     Stream.EmitRecord(bitc::METADATA_INDEX, IndexPos, IndexAbbrev);
2063     IndexPos.clear();
2064   }
2065 
2066   // Write the named metadata now.
2067   writeNamedMetadata(Record);
2068 
2069   auto AddDeclAttachedMetadata = [&](const GlobalObject &GO) {
2070     SmallVector<uint64_t, 4> Record;
2071     Record.push_back(VE.getValueID(&GO));
2072     pushGlobalMetadataAttachment(Record, GO);
2073     Stream.EmitRecord(bitc::METADATA_GLOBAL_DECL_ATTACHMENT, Record);
2074   };
2075   for (const Function &F : M)
2076     if (F.isDeclaration() && F.hasMetadata())
2077       AddDeclAttachedMetadata(F);
2078   // FIXME: Only store metadata for declarations here, and move data for global
2079   // variable definitions to a separate block (PR28134).
2080   for (const GlobalVariable &GV : M.globals())
2081     if (GV.hasMetadata())
2082       AddDeclAttachedMetadata(GV);
2083 
2084   Stream.ExitBlock();
2085 }
2086 
2087 void ModuleBitcodeWriter::writeFunctionMetadata(const Function &F) {
2088   if (!VE.hasMDs())
2089     return;
2090 
2091   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
2092   SmallVector<uint64_t, 64> Record;
2093   writeMetadataStrings(VE.getMDStrings(), Record);
2094   writeMetadataRecords(VE.getNonMDStrings(), Record);
2095   Stream.ExitBlock();
2096 }
2097 
2098 void ModuleBitcodeWriter::pushGlobalMetadataAttachment(
2099     SmallVectorImpl<uint64_t> &Record, const GlobalObject &GO) {
2100   // [n x [id, mdnode]]
2101   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2102   GO.getAllMetadata(MDs);
2103   for (const auto &I : MDs) {
2104     Record.push_back(I.first);
2105     Record.push_back(VE.getMetadataID(I.second));
2106   }
2107 }
2108 
2109 void ModuleBitcodeWriter::writeFunctionMetadataAttachment(const Function &F) {
2110   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
2111 
2112   SmallVector<uint64_t, 64> Record;
2113 
2114   if (F.hasMetadata()) {
2115     pushGlobalMetadataAttachment(Record, F);
2116     Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2117     Record.clear();
2118   }
2119 
2120   // Write metadata attachments
2121   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
2122   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2123   for (const BasicBlock &BB : F)
2124     for (const Instruction &I : BB) {
2125       MDs.clear();
2126       I.getAllMetadataOtherThanDebugLoc(MDs);
2127 
2128       // If no metadata, ignore instruction.
2129       if (MDs.empty()) continue;
2130 
2131       Record.push_back(VE.getInstructionID(&I));
2132 
2133       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
2134         Record.push_back(MDs[i].first);
2135         Record.push_back(VE.getMetadataID(MDs[i].second));
2136       }
2137       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2138       Record.clear();
2139     }
2140 
2141   Stream.ExitBlock();
2142 }
2143 
2144 void ModuleBitcodeWriter::writeModuleMetadataKinds() {
2145   SmallVector<uint64_t, 64> Record;
2146 
2147   // Write metadata kinds
2148   // METADATA_KIND - [n x [id, name]]
2149   SmallVector<StringRef, 8> Names;
2150   M.getMDKindNames(Names);
2151 
2152   if (Names.empty()) return;
2153 
2154   Stream.EnterSubblock(bitc::METADATA_KIND_BLOCK_ID, 3);
2155 
2156   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
2157     Record.push_back(MDKindID);
2158     StringRef KName = Names[MDKindID];
2159     Record.append(KName.begin(), KName.end());
2160 
2161     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
2162     Record.clear();
2163   }
2164 
2165   Stream.ExitBlock();
2166 }
2167 
2168 void ModuleBitcodeWriter::writeOperandBundleTags() {
2169   // Write metadata kinds
2170   //
2171   // OPERAND_BUNDLE_TAGS_BLOCK_ID : N x OPERAND_BUNDLE_TAG
2172   //
2173   // OPERAND_BUNDLE_TAG - [strchr x N]
2174 
2175   SmallVector<StringRef, 8> Tags;
2176   M.getOperandBundleTags(Tags);
2177 
2178   if (Tags.empty())
2179     return;
2180 
2181   Stream.EnterSubblock(bitc::OPERAND_BUNDLE_TAGS_BLOCK_ID, 3);
2182 
2183   SmallVector<uint64_t, 64> Record;
2184 
2185   for (auto Tag : Tags) {
2186     Record.append(Tag.begin(), Tag.end());
2187 
2188     Stream.EmitRecord(bitc::OPERAND_BUNDLE_TAG, Record, 0);
2189     Record.clear();
2190   }
2191 
2192   Stream.ExitBlock();
2193 }
2194 
2195 void ModuleBitcodeWriter::writeSyncScopeNames() {
2196   SmallVector<StringRef, 8> SSNs;
2197   M.getContext().getSyncScopeNames(SSNs);
2198   if (SSNs.empty())
2199     return;
2200 
2201   Stream.EnterSubblock(bitc::SYNC_SCOPE_NAMES_BLOCK_ID, 2);
2202 
2203   SmallVector<uint64_t, 64> Record;
2204   for (auto SSN : SSNs) {
2205     Record.append(SSN.begin(), SSN.end());
2206     Stream.EmitRecord(bitc::SYNC_SCOPE_NAME, Record, 0);
2207     Record.clear();
2208   }
2209 
2210   Stream.ExitBlock();
2211 }
2212 
2213 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
2214   if ((int64_t)V >= 0)
2215     Vals.push_back(V << 1);
2216   else
2217     Vals.push_back((-V << 1) | 1);
2218 }
2219 
2220 void ModuleBitcodeWriter::writeConstants(unsigned FirstVal, unsigned LastVal,
2221                                          bool isGlobal) {
2222   if (FirstVal == LastVal) return;
2223 
2224   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
2225 
2226   unsigned AggregateAbbrev = 0;
2227   unsigned String8Abbrev = 0;
2228   unsigned CString7Abbrev = 0;
2229   unsigned CString6Abbrev = 0;
2230   // If this is a constant pool for the module, emit module-specific abbrevs.
2231   if (isGlobal) {
2232     // Abbrev for CST_CODE_AGGREGATE.
2233     auto Abbv = std::make_shared<BitCodeAbbrev>();
2234     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
2235     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2236     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
2237     AggregateAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2238 
2239     // Abbrev for CST_CODE_STRING.
2240     Abbv = std::make_shared<BitCodeAbbrev>();
2241     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
2242     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2243     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2244     String8Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2245     // Abbrev for CST_CODE_CSTRING.
2246     Abbv = std::make_shared<BitCodeAbbrev>();
2247     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2248     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2249     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2250     CString7Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2251     // Abbrev for CST_CODE_CSTRING.
2252     Abbv = std::make_shared<BitCodeAbbrev>();
2253     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2254     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2255     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2256     CString6Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2257   }
2258 
2259   SmallVector<uint64_t, 64> Record;
2260 
2261   const ValueEnumerator::ValueList &Vals = VE.getValues();
2262   Type *LastTy = nullptr;
2263   for (unsigned i = FirstVal; i != LastVal; ++i) {
2264     const Value *V = Vals[i].first;
2265     // If we need to switch types, do so now.
2266     if (V->getType() != LastTy) {
2267       LastTy = V->getType();
2268       Record.push_back(VE.getTypeID(LastTy));
2269       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
2270                         CONSTANTS_SETTYPE_ABBREV);
2271       Record.clear();
2272     }
2273 
2274     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
2275       Record.push_back(unsigned(IA->hasSideEffects()) |
2276                        unsigned(IA->isAlignStack()) << 1 |
2277                        unsigned(IA->getDialect()&1) << 2);
2278 
2279       // Add the asm string.
2280       const std::string &AsmStr = IA->getAsmString();
2281       Record.push_back(AsmStr.size());
2282       Record.append(AsmStr.begin(), AsmStr.end());
2283 
2284       // Add the constraint string.
2285       const std::string &ConstraintStr = IA->getConstraintString();
2286       Record.push_back(ConstraintStr.size());
2287       Record.append(ConstraintStr.begin(), ConstraintStr.end());
2288       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
2289       Record.clear();
2290       continue;
2291     }
2292     const Constant *C = cast<Constant>(V);
2293     unsigned Code = -1U;
2294     unsigned AbbrevToUse = 0;
2295     if (C->isNullValue()) {
2296       Code = bitc::CST_CODE_NULL;
2297     } else if (isa<UndefValue>(C)) {
2298       Code = bitc::CST_CODE_UNDEF;
2299     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
2300       if (IV->getBitWidth() <= 64) {
2301         uint64_t V = IV->getSExtValue();
2302         emitSignedInt64(Record, V);
2303         Code = bitc::CST_CODE_INTEGER;
2304         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
2305       } else {                             // Wide integers, > 64 bits in size.
2306         // We have an arbitrary precision integer value to write whose
2307         // bit width is > 64. However, in canonical unsigned integer
2308         // format it is likely that the high bits are going to be zero.
2309         // So, we only write the number of active words.
2310         unsigned NWords = IV->getValue().getActiveWords();
2311         const uint64_t *RawWords = IV->getValue().getRawData();
2312         for (unsigned i = 0; i != NWords; ++i) {
2313           emitSignedInt64(Record, RawWords[i]);
2314         }
2315         Code = bitc::CST_CODE_WIDE_INTEGER;
2316       }
2317     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
2318       Code = bitc::CST_CODE_FLOAT;
2319       Type *Ty = CFP->getType();
2320       if (Ty->isHalfTy() || Ty->isFloatTy() || Ty->isDoubleTy()) {
2321         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
2322       } else if (Ty->isX86_FP80Ty()) {
2323         // api needed to prevent premature destruction
2324         // bits are not in the same order as a normal i80 APInt, compensate.
2325         APInt api = CFP->getValueAPF().bitcastToAPInt();
2326         const uint64_t *p = api.getRawData();
2327         Record.push_back((p[1] << 48) | (p[0] >> 16));
2328         Record.push_back(p[0] & 0xffffLL);
2329       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
2330         APInt api = CFP->getValueAPF().bitcastToAPInt();
2331         const uint64_t *p = api.getRawData();
2332         Record.push_back(p[0]);
2333         Record.push_back(p[1]);
2334       } else {
2335         assert(0 && "Unknown FP type!");
2336       }
2337     } else if (isa<ConstantDataSequential>(C) &&
2338                cast<ConstantDataSequential>(C)->isString()) {
2339       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
2340       // Emit constant strings specially.
2341       unsigned NumElts = Str->getNumElements();
2342       // If this is a null-terminated string, use the denser CSTRING encoding.
2343       if (Str->isCString()) {
2344         Code = bitc::CST_CODE_CSTRING;
2345         --NumElts;  // Don't encode the null, which isn't allowed by char6.
2346       } else {
2347         Code = bitc::CST_CODE_STRING;
2348         AbbrevToUse = String8Abbrev;
2349       }
2350       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
2351       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
2352       for (unsigned i = 0; i != NumElts; ++i) {
2353         unsigned char V = Str->getElementAsInteger(i);
2354         Record.push_back(V);
2355         isCStr7 &= (V & 128) == 0;
2356         if (isCStrChar6)
2357           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
2358       }
2359 
2360       if (isCStrChar6)
2361         AbbrevToUse = CString6Abbrev;
2362       else if (isCStr7)
2363         AbbrevToUse = CString7Abbrev;
2364     } else if (const ConstantDataSequential *CDS =
2365                   dyn_cast<ConstantDataSequential>(C)) {
2366       Code = bitc::CST_CODE_DATA;
2367       Type *EltTy = CDS->getType()->getElementType();
2368       if (isa<IntegerType>(EltTy)) {
2369         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2370           Record.push_back(CDS->getElementAsInteger(i));
2371       } else {
2372         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2373           Record.push_back(
2374               CDS->getElementAsAPFloat(i).bitcastToAPInt().getLimitedValue());
2375       }
2376     } else if (isa<ConstantAggregate>(C)) {
2377       Code = bitc::CST_CODE_AGGREGATE;
2378       for (const Value *Op : C->operands())
2379         Record.push_back(VE.getValueID(Op));
2380       AbbrevToUse = AggregateAbbrev;
2381     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
2382       switch (CE->getOpcode()) {
2383       default:
2384         if (Instruction::isCast(CE->getOpcode())) {
2385           Code = bitc::CST_CODE_CE_CAST;
2386           Record.push_back(getEncodedCastOpcode(CE->getOpcode()));
2387           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2388           Record.push_back(VE.getValueID(C->getOperand(0)));
2389           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
2390         } else {
2391           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
2392           Code = bitc::CST_CODE_CE_BINOP;
2393           Record.push_back(getEncodedBinaryOpcode(CE->getOpcode()));
2394           Record.push_back(VE.getValueID(C->getOperand(0)));
2395           Record.push_back(VE.getValueID(C->getOperand(1)));
2396           uint64_t Flags = getOptimizationFlags(CE);
2397           if (Flags != 0)
2398             Record.push_back(Flags);
2399         }
2400         break;
2401       case Instruction::FNeg: {
2402         assert(CE->getNumOperands() == 1 && "Unknown constant expr!");
2403         Code = bitc::CST_CODE_CE_UNOP;
2404         Record.push_back(getEncodedUnaryOpcode(CE->getOpcode()));
2405         Record.push_back(VE.getValueID(C->getOperand(0)));
2406         uint64_t Flags = getOptimizationFlags(CE);
2407         if (Flags != 0)
2408           Record.push_back(Flags);
2409         break;
2410       }
2411       case Instruction::GetElementPtr: {
2412         Code = bitc::CST_CODE_CE_GEP;
2413         const auto *GO = cast<GEPOperator>(C);
2414         Record.push_back(VE.getTypeID(GO->getSourceElementType()));
2415         if (Optional<unsigned> Idx = GO->getInRangeIndex()) {
2416           Code = bitc::CST_CODE_CE_GEP_WITH_INRANGE_INDEX;
2417           Record.push_back((*Idx << 1) | GO->isInBounds());
2418         } else if (GO->isInBounds())
2419           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
2420         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
2421           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
2422           Record.push_back(VE.getValueID(C->getOperand(i)));
2423         }
2424         break;
2425       }
2426       case Instruction::Select:
2427         Code = bitc::CST_CODE_CE_SELECT;
2428         Record.push_back(VE.getValueID(C->getOperand(0)));
2429         Record.push_back(VE.getValueID(C->getOperand(1)));
2430         Record.push_back(VE.getValueID(C->getOperand(2)));
2431         break;
2432       case Instruction::ExtractElement:
2433         Code = bitc::CST_CODE_CE_EXTRACTELT;
2434         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2435         Record.push_back(VE.getValueID(C->getOperand(0)));
2436         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
2437         Record.push_back(VE.getValueID(C->getOperand(1)));
2438         break;
2439       case Instruction::InsertElement:
2440         Code = bitc::CST_CODE_CE_INSERTELT;
2441         Record.push_back(VE.getValueID(C->getOperand(0)));
2442         Record.push_back(VE.getValueID(C->getOperand(1)));
2443         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
2444         Record.push_back(VE.getValueID(C->getOperand(2)));
2445         break;
2446       case Instruction::ShuffleVector:
2447         // If the return type and argument types are the same, this is a
2448         // standard shufflevector instruction.  If the types are different,
2449         // then the shuffle is widening or truncating the input vectors, and
2450         // the argument type must also be encoded.
2451         if (C->getType() == C->getOperand(0)->getType()) {
2452           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
2453         } else {
2454           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
2455           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2456         }
2457         Record.push_back(VE.getValueID(C->getOperand(0)));
2458         Record.push_back(VE.getValueID(C->getOperand(1)));
2459         Record.push_back(VE.getValueID(C->getOperand(2)));
2460         break;
2461       case Instruction::ICmp:
2462       case Instruction::FCmp:
2463         Code = bitc::CST_CODE_CE_CMP;
2464         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2465         Record.push_back(VE.getValueID(C->getOperand(0)));
2466         Record.push_back(VE.getValueID(C->getOperand(1)));
2467         Record.push_back(CE->getPredicate());
2468         break;
2469       }
2470     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
2471       Code = bitc::CST_CODE_BLOCKADDRESS;
2472       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
2473       Record.push_back(VE.getValueID(BA->getFunction()));
2474       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
2475     } else {
2476 #ifndef NDEBUG
2477       C->dump();
2478 #endif
2479       llvm_unreachable("Unknown constant!");
2480     }
2481     Stream.EmitRecord(Code, Record, AbbrevToUse);
2482     Record.clear();
2483   }
2484 
2485   Stream.ExitBlock();
2486 }
2487 
2488 void ModuleBitcodeWriter::writeModuleConstants() {
2489   const ValueEnumerator::ValueList &Vals = VE.getValues();
2490 
2491   // Find the first constant to emit, which is the first non-globalvalue value.
2492   // We know globalvalues have been emitted by WriteModuleInfo.
2493   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
2494     if (!isa<GlobalValue>(Vals[i].first)) {
2495       writeConstants(i, Vals.size(), true);
2496       return;
2497     }
2498   }
2499 }
2500 
2501 /// pushValueAndType - The file has to encode both the value and type id for
2502 /// many values, because we need to know what type to create for forward
2503 /// references.  However, most operands are not forward references, so this type
2504 /// field is not needed.
2505 ///
2506 /// This function adds V's value ID to Vals.  If the value ID is higher than the
2507 /// instruction ID, then it is a forward reference, and it also includes the
2508 /// type ID.  The value ID that is written is encoded relative to the InstID.
2509 bool ModuleBitcodeWriter::pushValueAndType(const Value *V, unsigned InstID,
2510                                            SmallVectorImpl<unsigned> &Vals) {
2511   unsigned ValID = VE.getValueID(V);
2512   // Make encoding relative to the InstID.
2513   Vals.push_back(InstID - ValID);
2514   if (ValID >= InstID) {
2515     Vals.push_back(VE.getTypeID(V->getType()));
2516     return true;
2517   }
2518   return false;
2519 }
2520 
2521 void ModuleBitcodeWriter::writeOperandBundles(ImmutableCallSite CS,
2522                                               unsigned InstID) {
2523   SmallVector<unsigned, 64> Record;
2524   LLVMContext &C = CS.getInstruction()->getContext();
2525 
2526   for (unsigned i = 0, e = CS.getNumOperandBundles(); i != e; ++i) {
2527     const auto &Bundle = CS.getOperandBundleAt(i);
2528     Record.push_back(C.getOperandBundleTagID(Bundle.getTagName()));
2529 
2530     for (auto &Input : Bundle.Inputs)
2531       pushValueAndType(Input, InstID, Record);
2532 
2533     Stream.EmitRecord(bitc::FUNC_CODE_OPERAND_BUNDLE, Record);
2534     Record.clear();
2535   }
2536 }
2537 
2538 /// pushValue - Like pushValueAndType, but where the type of the value is
2539 /// omitted (perhaps it was already encoded in an earlier operand).
2540 void ModuleBitcodeWriter::pushValue(const Value *V, unsigned InstID,
2541                                     SmallVectorImpl<unsigned> &Vals) {
2542   unsigned ValID = VE.getValueID(V);
2543   Vals.push_back(InstID - ValID);
2544 }
2545 
2546 void ModuleBitcodeWriter::pushValueSigned(const Value *V, unsigned InstID,
2547                                           SmallVectorImpl<uint64_t> &Vals) {
2548   unsigned ValID = VE.getValueID(V);
2549   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
2550   emitSignedInt64(Vals, diff);
2551 }
2552 
2553 /// WriteInstruction - Emit an instruction to the specified stream.
2554 void ModuleBitcodeWriter::writeInstruction(const Instruction &I,
2555                                            unsigned InstID,
2556                                            SmallVectorImpl<unsigned> &Vals) {
2557   unsigned Code = 0;
2558   unsigned AbbrevToUse = 0;
2559   VE.setInstructionID(&I);
2560   switch (I.getOpcode()) {
2561   default:
2562     if (Instruction::isCast(I.getOpcode())) {
2563       Code = bitc::FUNC_CODE_INST_CAST;
2564       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2565         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
2566       Vals.push_back(VE.getTypeID(I.getType()));
2567       Vals.push_back(getEncodedCastOpcode(I.getOpcode()));
2568     } else {
2569       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
2570       Code = bitc::FUNC_CODE_INST_BINOP;
2571       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2572         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
2573       pushValue(I.getOperand(1), InstID, Vals);
2574       Vals.push_back(getEncodedBinaryOpcode(I.getOpcode()));
2575       uint64_t Flags = getOptimizationFlags(&I);
2576       if (Flags != 0) {
2577         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
2578           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
2579         Vals.push_back(Flags);
2580       }
2581     }
2582     break;
2583   case Instruction::FNeg: {
2584     Code = bitc::FUNC_CODE_INST_UNOP;
2585     if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2586       AbbrevToUse = FUNCTION_INST_UNOP_ABBREV;
2587     Vals.push_back(getEncodedUnaryOpcode(I.getOpcode()));
2588     uint64_t Flags = getOptimizationFlags(&I);
2589     if (Flags != 0) {
2590       if (AbbrevToUse == FUNCTION_INST_UNOP_ABBREV)
2591         AbbrevToUse = FUNCTION_INST_UNOP_FLAGS_ABBREV;
2592       Vals.push_back(Flags);
2593     }
2594     break;
2595   }
2596   case Instruction::GetElementPtr: {
2597     Code = bitc::FUNC_CODE_INST_GEP;
2598     AbbrevToUse = FUNCTION_INST_GEP_ABBREV;
2599     auto &GEPInst = cast<GetElementPtrInst>(I);
2600     Vals.push_back(GEPInst.isInBounds());
2601     Vals.push_back(VE.getTypeID(GEPInst.getSourceElementType()));
2602     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
2603       pushValueAndType(I.getOperand(i), InstID, Vals);
2604     break;
2605   }
2606   case Instruction::ExtractValue: {
2607     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
2608     pushValueAndType(I.getOperand(0), InstID, Vals);
2609     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
2610     Vals.append(EVI->idx_begin(), EVI->idx_end());
2611     break;
2612   }
2613   case Instruction::InsertValue: {
2614     Code = bitc::FUNC_CODE_INST_INSERTVAL;
2615     pushValueAndType(I.getOperand(0), InstID, Vals);
2616     pushValueAndType(I.getOperand(1), InstID, Vals);
2617     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
2618     Vals.append(IVI->idx_begin(), IVI->idx_end());
2619     break;
2620   }
2621   case Instruction::Select:
2622     Code = bitc::FUNC_CODE_INST_VSELECT;
2623     pushValueAndType(I.getOperand(1), InstID, Vals);
2624     pushValue(I.getOperand(2), InstID, Vals);
2625     pushValueAndType(I.getOperand(0), InstID, Vals);
2626     break;
2627   case Instruction::ExtractElement:
2628     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
2629     pushValueAndType(I.getOperand(0), InstID, Vals);
2630     pushValueAndType(I.getOperand(1), InstID, Vals);
2631     break;
2632   case Instruction::InsertElement:
2633     Code = bitc::FUNC_CODE_INST_INSERTELT;
2634     pushValueAndType(I.getOperand(0), InstID, Vals);
2635     pushValue(I.getOperand(1), InstID, Vals);
2636     pushValueAndType(I.getOperand(2), InstID, Vals);
2637     break;
2638   case Instruction::ShuffleVector:
2639     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
2640     pushValueAndType(I.getOperand(0), InstID, Vals);
2641     pushValue(I.getOperand(1), InstID, Vals);
2642     pushValue(I.getOperand(2), InstID, Vals);
2643     break;
2644   case Instruction::ICmp:
2645   case Instruction::FCmp: {
2646     // compare returning Int1Ty or vector of Int1Ty
2647     Code = bitc::FUNC_CODE_INST_CMP2;
2648     pushValueAndType(I.getOperand(0), InstID, Vals);
2649     pushValue(I.getOperand(1), InstID, Vals);
2650     Vals.push_back(cast<CmpInst>(I).getPredicate());
2651     uint64_t Flags = getOptimizationFlags(&I);
2652     if (Flags != 0)
2653       Vals.push_back(Flags);
2654     break;
2655   }
2656 
2657   case Instruction::Ret:
2658     {
2659       Code = bitc::FUNC_CODE_INST_RET;
2660       unsigned NumOperands = I.getNumOperands();
2661       if (NumOperands == 0)
2662         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
2663       else if (NumOperands == 1) {
2664         if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2665           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
2666       } else {
2667         for (unsigned i = 0, e = NumOperands; i != e; ++i)
2668           pushValueAndType(I.getOperand(i), InstID, Vals);
2669       }
2670     }
2671     break;
2672   case Instruction::Br:
2673     {
2674       Code = bitc::FUNC_CODE_INST_BR;
2675       const BranchInst &II = cast<BranchInst>(I);
2676       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
2677       if (II.isConditional()) {
2678         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
2679         pushValue(II.getCondition(), InstID, Vals);
2680       }
2681     }
2682     break;
2683   case Instruction::Switch:
2684     {
2685       Code = bitc::FUNC_CODE_INST_SWITCH;
2686       const SwitchInst &SI = cast<SwitchInst>(I);
2687       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
2688       pushValue(SI.getCondition(), InstID, Vals);
2689       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
2690       for (auto Case : SI.cases()) {
2691         Vals.push_back(VE.getValueID(Case.getCaseValue()));
2692         Vals.push_back(VE.getValueID(Case.getCaseSuccessor()));
2693       }
2694     }
2695     break;
2696   case Instruction::IndirectBr:
2697     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
2698     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2699     // Encode the address operand as relative, but not the basic blocks.
2700     pushValue(I.getOperand(0), InstID, Vals);
2701     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
2702       Vals.push_back(VE.getValueID(I.getOperand(i)));
2703     break;
2704 
2705   case Instruction::Invoke: {
2706     const InvokeInst *II = cast<InvokeInst>(&I);
2707     const Value *Callee = II->getCalledValue();
2708     FunctionType *FTy = II->getFunctionType();
2709 
2710     if (II->hasOperandBundles())
2711       writeOperandBundles(II, InstID);
2712 
2713     Code = bitc::FUNC_CODE_INST_INVOKE;
2714 
2715     Vals.push_back(VE.getAttributeListID(II->getAttributes()));
2716     Vals.push_back(II->getCallingConv() | 1 << 13);
2717     Vals.push_back(VE.getValueID(II->getNormalDest()));
2718     Vals.push_back(VE.getValueID(II->getUnwindDest()));
2719     Vals.push_back(VE.getTypeID(FTy));
2720     pushValueAndType(Callee, InstID, Vals);
2721 
2722     // Emit value #'s for the fixed parameters.
2723     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
2724       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
2725 
2726     // Emit type/value pairs for varargs params.
2727     if (FTy->isVarArg()) {
2728       for (unsigned i = FTy->getNumParams(), e = II->getNumArgOperands();
2729            i != e; ++i)
2730         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
2731     }
2732     break;
2733   }
2734   case Instruction::Resume:
2735     Code = bitc::FUNC_CODE_INST_RESUME;
2736     pushValueAndType(I.getOperand(0), InstID, Vals);
2737     break;
2738   case Instruction::CleanupRet: {
2739     Code = bitc::FUNC_CODE_INST_CLEANUPRET;
2740     const auto &CRI = cast<CleanupReturnInst>(I);
2741     pushValue(CRI.getCleanupPad(), InstID, Vals);
2742     if (CRI.hasUnwindDest())
2743       Vals.push_back(VE.getValueID(CRI.getUnwindDest()));
2744     break;
2745   }
2746   case Instruction::CatchRet: {
2747     Code = bitc::FUNC_CODE_INST_CATCHRET;
2748     const auto &CRI = cast<CatchReturnInst>(I);
2749     pushValue(CRI.getCatchPad(), InstID, Vals);
2750     Vals.push_back(VE.getValueID(CRI.getSuccessor()));
2751     break;
2752   }
2753   case Instruction::CleanupPad:
2754   case Instruction::CatchPad: {
2755     const auto &FuncletPad = cast<FuncletPadInst>(I);
2756     Code = isa<CatchPadInst>(FuncletPad) ? bitc::FUNC_CODE_INST_CATCHPAD
2757                                          : bitc::FUNC_CODE_INST_CLEANUPPAD;
2758     pushValue(FuncletPad.getParentPad(), InstID, Vals);
2759 
2760     unsigned NumArgOperands = FuncletPad.getNumArgOperands();
2761     Vals.push_back(NumArgOperands);
2762     for (unsigned Op = 0; Op != NumArgOperands; ++Op)
2763       pushValueAndType(FuncletPad.getArgOperand(Op), InstID, Vals);
2764     break;
2765   }
2766   case Instruction::CatchSwitch: {
2767     Code = bitc::FUNC_CODE_INST_CATCHSWITCH;
2768     const auto &CatchSwitch = cast<CatchSwitchInst>(I);
2769 
2770     pushValue(CatchSwitch.getParentPad(), InstID, Vals);
2771 
2772     unsigned NumHandlers = CatchSwitch.getNumHandlers();
2773     Vals.push_back(NumHandlers);
2774     for (const BasicBlock *CatchPadBB : CatchSwitch.handlers())
2775       Vals.push_back(VE.getValueID(CatchPadBB));
2776 
2777     if (CatchSwitch.hasUnwindDest())
2778       Vals.push_back(VE.getValueID(CatchSwitch.getUnwindDest()));
2779     break;
2780   }
2781   case Instruction::Unreachable:
2782     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
2783     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
2784     break;
2785 
2786   case Instruction::PHI: {
2787     const PHINode &PN = cast<PHINode>(I);
2788     Code = bitc::FUNC_CODE_INST_PHI;
2789     // With the newer instruction encoding, forward references could give
2790     // negative valued IDs.  This is most common for PHIs, so we use
2791     // signed VBRs.
2792     SmallVector<uint64_t, 128> Vals64;
2793     Vals64.push_back(VE.getTypeID(PN.getType()));
2794     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
2795       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64);
2796       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
2797     }
2798     // Emit a Vals64 vector and exit.
2799     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
2800     Vals64.clear();
2801     return;
2802   }
2803 
2804   case Instruction::LandingPad: {
2805     const LandingPadInst &LP = cast<LandingPadInst>(I);
2806     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
2807     Vals.push_back(VE.getTypeID(LP.getType()));
2808     Vals.push_back(LP.isCleanup());
2809     Vals.push_back(LP.getNumClauses());
2810     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
2811       if (LP.isCatch(I))
2812         Vals.push_back(LandingPadInst::Catch);
2813       else
2814         Vals.push_back(LandingPadInst::Filter);
2815       pushValueAndType(LP.getClause(I), InstID, Vals);
2816     }
2817     break;
2818   }
2819 
2820   case Instruction::Alloca: {
2821     Code = bitc::FUNC_CODE_INST_ALLOCA;
2822     const AllocaInst &AI = cast<AllocaInst>(I);
2823     Vals.push_back(VE.getTypeID(AI.getAllocatedType()));
2824     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2825     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
2826     unsigned AlignRecord = Log2_32(AI.getAlignment()) + 1;
2827     assert(Log2_32(Value::MaximumAlignment) + 1 < 1 << 5 &&
2828            "not enough bits for maximum alignment");
2829     assert(AlignRecord < 1 << 5 && "alignment greater than 1 << 64");
2830     AlignRecord |= AI.isUsedWithInAlloca() << 5;
2831     AlignRecord |= 1 << 6;
2832     AlignRecord |= AI.isSwiftError() << 7;
2833     Vals.push_back(AlignRecord);
2834     break;
2835   }
2836 
2837   case Instruction::Load:
2838     if (cast<LoadInst>(I).isAtomic()) {
2839       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
2840       pushValueAndType(I.getOperand(0), InstID, Vals);
2841     } else {
2842       Code = bitc::FUNC_CODE_INST_LOAD;
2843       if (!pushValueAndType(I.getOperand(0), InstID, Vals)) // ptr
2844         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
2845     }
2846     Vals.push_back(VE.getTypeID(I.getType()));
2847     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
2848     Vals.push_back(cast<LoadInst>(I).isVolatile());
2849     if (cast<LoadInst>(I).isAtomic()) {
2850       Vals.push_back(getEncodedOrdering(cast<LoadInst>(I).getOrdering()));
2851       Vals.push_back(getEncodedSyncScopeID(cast<LoadInst>(I).getSyncScopeID()));
2852     }
2853     break;
2854   case Instruction::Store:
2855     if (cast<StoreInst>(I).isAtomic())
2856       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
2857     else
2858       Code = bitc::FUNC_CODE_INST_STORE;
2859     pushValueAndType(I.getOperand(1), InstID, Vals); // ptrty + ptr
2860     pushValueAndType(I.getOperand(0), InstID, Vals); // valty + val
2861     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
2862     Vals.push_back(cast<StoreInst>(I).isVolatile());
2863     if (cast<StoreInst>(I).isAtomic()) {
2864       Vals.push_back(getEncodedOrdering(cast<StoreInst>(I).getOrdering()));
2865       Vals.push_back(
2866           getEncodedSyncScopeID(cast<StoreInst>(I).getSyncScopeID()));
2867     }
2868     break;
2869   case Instruction::AtomicCmpXchg:
2870     Code = bitc::FUNC_CODE_INST_CMPXCHG;
2871     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
2872     pushValueAndType(I.getOperand(1), InstID, Vals); // cmp.
2873     pushValue(I.getOperand(2), InstID, Vals);        // newval.
2874     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
2875     Vals.push_back(
2876         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
2877     Vals.push_back(
2878         getEncodedSyncScopeID(cast<AtomicCmpXchgInst>(I).getSyncScopeID()));
2879     Vals.push_back(
2880         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
2881     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
2882     break;
2883   case Instruction::AtomicRMW:
2884     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
2885     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
2886     pushValue(I.getOperand(1), InstID, Vals);        // val.
2887     Vals.push_back(
2888         getEncodedRMWOperation(cast<AtomicRMWInst>(I).getOperation()));
2889     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
2890     Vals.push_back(getEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
2891     Vals.push_back(
2892         getEncodedSyncScopeID(cast<AtomicRMWInst>(I).getSyncScopeID()));
2893     break;
2894   case Instruction::Fence:
2895     Code = bitc::FUNC_CODE_INST_FENCE;
2896     Vals.push_back(getEncodedOrdering(cast<FenceInst>(I).getOrdering()));
2897     Vals.push_back(getEncodedSyncScopeID(cast<FenceInst>(I).getSyncScopeID()));
2898     break;
2899   case Instruction::Call: {
2900     const CallInst &CI = cast<CallInst>(I);
2901     FunctionType *FTy = CI.getFunctionType();
2902 
2903     if (CI.hasOperandBundles())
2904       writeOperandBundles(&CI, InstID);
2905 
2906     Code = bitc::FUNC_CODE_INST_CALL;
2907 
2908     Vals.push_back(VE.getAttributeListID(CI.getAttributes()));
2909 
2910     unsigned Flags = getOptimizationFlags(&I);
2911     Vals.push_back(CI.getCallingConv() << bitc::CALL_CCONV |
2912                    unsigned(CI.isTailCall()) << bitc::CALL_TAIL |
2913                    unsigned(CI.isMustTailCall()) << bitc::CALL_MUSTTAIL |
2914                    1 << bitc::CALL_EXPLICIT_TYPE |
2915                    unsigned(CI.isNoTailCall()) << bitc::CALL_NOTAIL |
2916                    unsigned(Flags != 0) << bitc::CALL_FMF);
2917     if (Flags != 0)
2918       Vals.push_back(Flags);
2919 
2920     Vals.push_back(VE.getTypeID(FTy));
2921     pushValueAndType(CI.getCalledValue(), InstID, Vals); // Callee
2922 
2923     // Emit value #'s for the fixed parameters.
2924     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
2925       // Check for labels (can happen with asm labels).
2926       if (FTy->getParamType(i)->isLabelTy())
2927         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
2928       else
2929         pushValue(CI.getArgOperand(i), InstID, Vals); // fixed param.
2930     }
2931 
2932     // Emit type/value pairs for varargs params.
2933     if (FTy->isVarArg()) {
2934       for (unsigned i = FTy->getNumParams(), e = CI.getNumArgOperands();
2935            i != e; ++i)
2936         pushValueAndType(CI.getArgOperand(i), InstID, Vals); // varargs
2937     }
2938     break;
2939   }
2940   case Instruction::VAArg:
2941     Code = bitc::FUNC_CODE_INST_VAARG;
2942     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
2943     pushValue(I.getOperand(0), InstID, Vals);                   // valist.
2944     Vals.push_back(VE.getTypeID(I.getType())); // restype.
2945     break;
2946   }
2947 
2948   Stream.EmitRecord(Code, Vals, AbbrevToUse);
2949   Vals.clear();
2950 }
2951 
2952 /// Write a GlobalValue VST to the module. The purpose of this data structure is
2953 /// to allow clients to efficiently find the function body.
2954 void ModuleBitcodeWriter::writeGlobalValueSymbolTable(
2955   DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
2956   // Get the offset of the VST we are writing, and backpatch it into
2957   // the VST forward declaration record.
2958   uint64_t VSTOffset = Stream.GetCurrentBitNo();
2959   // The BitcodeStartBit was the stream offset of the identification block.
2960   VSTOffset -= bitcodeStartBit();
2961   assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
2962   // Note that we add 1 here because the offset is relative to one word
2963   // before the start of the identification block, which was historically
2964   // always the start of the regular bitcode header.
2965   Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32 + 1);
2966 
2967   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
2968 
2969   auto Abbv = std::make_shared<BitCodeAbbrev>();
2970   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
2971   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
2972   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
2973   unsigned FnEntryAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2974 
2975   for (const Function &F : M) {
2976     uint64_t Record[2];
2977 
2978     if (F.isDeclaration())
2979       continue;
2980 
2981     Record[0] = VE.getValueID(&F);
2982 
2983     // Save the word offset of the function (from the start of the
2984     // actual bitcode written to the stream).
2985     uint64_t BitcodeIndex = FunctionToBitcodeIndex[&F] - bitcodeStartBit();
2986     assert((BitcodeIndex & 31) == 0 && "function block not 32-bit aligned");
2987     // Note that we add 1 here because the offset is relative to one word
2988     // before the start of the identification block, which was historically
2989     // always the start of the regular bitcode header.
2990     Record[1] = BitcodeIndex / 32 + 1;
2991 
2992     Stream.EmitRecord(bitc::VST_CODE_FNENTRY, Record, FnEntryAbbrev);
2993   }
2994 
2995   Stream.ExitBlock();
2996 }
2997 
2998 /// Emit names for arguments, instructions and basic blocks in a function.
2999 void ModuleBitcodeWriter::writeFunctionLevelValueSymbolTable(
3000     const ValueSymbolTable &VST) {
3001   if (VST.empty())
3002     return;
3003 
3004   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3005 
3006   // FIXME: Set up the abbrev, we know how many values there are!
3007   // FIXME: We know if the type names can use 7-bit ascii.
3008   SmallVector<uint64_t, 64> NameVals;
3009 
3010   for (const ValueName &Name : VST) {
3011     // Figure out the encoding to use for the name.
3012     StringEncoding Bits = getStringEncoding(Name.getKey());
3013 
3014     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
3015     NameVals.push_back(VE.getValueID(Name.getValue()));
3016 
3017     // VST_CODE_ENTRY:   [valueid, namechar x N]
3018     // VST_CODE_BBENTRY: [bbid, namechar x N]
3019     unsigned Code;
3020     if (isa<BasicBlock>(Name.getValue())) {
3021       Code = bitc::VST_CODE_BBENTRY;
3022       if (Bits == SE_Char6)
3023         AbbrevToUse = VST_BBENTRY_6_ABBREV;
3024     } else {
3025       Code = bitc::VST_CODE_ENTRY;
3026       if (Bits == SE_Char6)
3027         AbbrevToUse = VST_ENTRY_6_ABBREV;
3028       else if (Bits == SE_Fixed7)
3029         AbbrevToUse = VST_ENTRY_7_ABBREV;
3030     }
3031 
3032     for (const auto P : Name.getKey())
3033       NameVals.push_back((unsigned char)P);
3034 
3035     // Emit the finished record.
3036     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
3037     NameVals.clear();
3038   }
3039 
3040   Stream.ExitBlock();
3041 }
3042 
3043 void ModuleBitcodeWriter::writeUseList(UseListOrder &&Order) {
3044   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
3045   unsigned Code;
3046   if (isa<BasicBlock>(Order.V))
3047     Code = bitc::USELIST_CODE_BB;
3048   else
3049     Code = bitc::USELIST_CODE_DEFAULT;
3050 
3051   SmallVector<uint64_t, 64> Record(Order.Shuffle.begin(), Order.Shuffle.end());
3052   Record.push_back(VE.getValueID(Order.V));
3053   Stream.EmitRecord(Code, Record);
3054 }
3055 
3056 void ModuleBitcodeWriter::writeUseListBlock(const Function *F) {
3057   assert(VE.shouldPreserveUseListOrder() &&
3058          "Expected to be preserving use-list order");
3059 
3060   auto hasMore = [&]() {
3061     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
3062   };
3063   if (!hasMore())
3064     // Nothing to do.
3065     return;
3066 
3067   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
3068   while (hasMore()) {
3069     writeUseList(std::move(VE.UseListOrders.back()));
3070     VE.UseListOrders.pop_back();
3071   }
3072   Stream.ExitBlock();
3073 }
3074 
3075 /// Emit a function body to the module stream.
3076 void ModuleBitcodeWriter::writeFunction(
3077     const Function &F,
3078     DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3079   // Save the bitcode index of the start of this function block for recording
3080   // in the VST.
3081   FunctionToBitcodeIndex[&F] = Stream.GetCurrentBitNo();
3082 
3083   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
3084   VE.incorporateFunction(F);
3085 
3086   SmallVector<unsigned, 64> Vals;
3087 
3088   // Emit the number of basic blocks, so the reader can create them ahead of
3089   // time.
3090   Vals.push_back(VE.getBasicBlocks().size());
3091   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
3092   Vals.clear();
3093 
3094   // If there are function-local constants, emit them now.
3095   unsigned CstStart, CstEnd;
3096   VE.getFunctionConstantRange(CstStart, CstEnd);
3097   writeConstants(CstStart, CstEnd, false);
3098 
3099   // If there is function-local metadata, emit it now.
3100   writeFunctionMetadata(F);
3101 
3102   // Keep a running idea of what the instruction ID is.
3103   unsigned InstID = CstEnd;
3104 
3105   bool NeedsMetadataAttachment = F.hasMetadata();
3106 
3107   DILocation *LastDL = nullptr;
3108   // Finally, emit all the instructions, in order.
3109   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
3110     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
3111          I != E; ++I) {
3112       writeInstruction(*I, InstID, Vals);
3113 
3114       if (!I->getType()->isVoidTy())
3115         ++InstID;
3116 
3117       // If the instruction has metadata, write a metadata attachment later.
3118       NeedsMetadataAttachment |= I->hasMetadataOtherThanDebugLoc();
3119 
3120       // If the instruction has a debug location, emit it.
3121       DILocation *DL = I->getDebugLoc();
3122       if (!DL)
3123         continue;
3124 
3125       if (DL == LastDL) {
3126         // Just repeat the same debug loc as last time.
3127         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
3128         continue;
3129       }
3130 
3131       Vals.push_back(DL->getLine());
3132       Vals.push_back(DL->getColumn());
3133       Vals.push_back(VE.getMetadataOrNullID(DL->getScope()));
3134       Vals.push_back(VE.getMetadataOrNullID(DL->getInlinedAt()));
3135       Vals.push_back(DL->isImplicitCode());
3136       Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
3137       Vals.clear();
3138 
3139       LastDL = DL;
3140     }
3141 
3142   // Emit names for all the instructions etc.
3143   if (auto *Symtab = F.getValueSymbolTable())
3144     writeFunctionLevelValueSymbolTable(*Symtab);
3145 
3146   if (NeedsMetadataAttachment)
3147     writeFunctionMetadataAttachment(F);
3148   if (VE.shouldPreserveUseListOrder())
3149     writeUseListBlock(&F);
3150   VE.purgeFunction();
3151   Stream.ExitBlock();
3152 }
3153 
3154 // Emit blockinfo, which defines the standard abbreviations etc.
3155 void ModuleBitcodeWriter::writeBlockInfo() {
3156   // We only want to emit block info records for blocks that have multiple
3157   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
3158   // Other blocks can define their abbrevs inline.
3159   Stream.EnterBlockInfoBlock();
3160 
3161   { // 8-bit fixed-width VST_CODE_ENTRY/VST_CODE_BBENTRY strings.
3162     auto Abbv = std::make_shared<BitCodeAbbrev>();
3163     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
3164     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3165     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3166     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3167     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3168         VST_ENTRY_8_ABBREV)
3169       llvm_unreachable("Unexpected abbrev ordering!");
3170   }
3171 
3172   { // 7-bit fixed width VST_CODE_ENTRY strings.
3173     auto Abbv = std::make_shared<BitCodeAbbrev>();
3174     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3175     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3176     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3177     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3178     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3179         VST_ENTRY_7_ABBREV)
3180       llvm_unreachable("Unexpected abbrev ordering!");
3181   }
3182   { // 6-bit char6 VST_CODE_ENTRY strings.
3183     auto Abbv = std::make_shared<BitCodeAbbrev>();
3184     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3185     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3186     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3187     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3188     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3189         VST_ENTRY_6_ABBREV)
3190       llvm_unreachable("Unexpected abbrev ordering!");
3191   }
3192   { // 6-bit char6 VST_CODE_BBENTRY strings.
3193     auto Abbv = std::make_shared<BitCodeAbbrev>();
3194     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
3195     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3196     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3197     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3198     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3199         VST_BBENTRY_6_ABBREV)
3200       llvm_unreachable("Unexpected abbrev ordering!");
3201   }
3202 
3203   { // SETTYPE abbrev for CONSTANTS_BLOCK.
3204     auto Abbv = std::make_shared<BitCodeAbbrev>();
3205     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
3206     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
3207                               VE.computeBitsRequiredForTypeIndicies()));
3208     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3209         CONSTANTS_SETTYPE_ABBREV)
3210       llvm_unreachable("Unexpected abbrev ordering!");
3211   }
3212 
3213   { // INTEGER abbrev for CONSTANTS_BLOCK.
3214     auto Abbv = std::make_shared<BitCodeAbbrev>();
3215     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
3216     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3217     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3218         CONSTANTS_INTEGER_ABBREV)
3219       llvm_unreachable("Unexpected abbrev ordering!");
3220   }
3221 
3222   { // CE_CAST abbrev for CONSTANTS_BLOCK.
3223     auto Abbv = std::make_shared<BitCodeAbbrev>();
3224     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
3225     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
3226     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
3227                               VE.computeBitsRequiredForTypeIndicies()));
3228     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
3229 
3230     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3231         CONSTANTS_CE_CAST_Abbrev)
3232       llvm_unreachable("Unexpected abbrev ordering!");
3233   }
3234   { // NULL abbrev for CONSTANTS_BLOCK.
3235     auto Abbv = std::make_shared<BitCodeAbbrev>();
3236     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
3237     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3238         CONSTANTS_NULL_Abbrev)
3239       llvm_unreachable("Unexpected abbrev ordering!");
3240   }
3241 
3242   // FIXME: This should only use space for first class types!
3243 
3244   { // INST_LOAD abbrev for FUNCTION_BLOCK.
3245     auto Abbv = std::make_shared<BitCodeAbbrev>();
3246     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
3247     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
3248     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
3249                               VE.computeBitsRequiredForTypeIndicies()));
3250     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
3251     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
3252     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3253         FUNCTION_INST_LOAD_ABBREV)
3254       llvm_unreachable("Unexpected abbrev ordering!");
3255   }
3256   { // INST_UNOP abbrev for FUNCTION_BLOCK.
3257     auto Abbv = std::make_shared<BitCodeAbbrev>();
3258     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3259     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3260     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3261     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3262         FUNCTION_INST_UNOP_ABBREV)
3263       llvm_unreachable("Unexpected abbrev ordering!");
3264   }
3265   { // INST_UNOP_FLAGS abbrev for FUNCTION_BLOCK.
3266     auto Abbv = std::make_shared<BitCodeAbbrev>();
3267     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3268     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3269     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3270     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3271     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3272         FUNCTION_INST_UNOP_FLAGS_ABBREV)
3273       llvm_unreachable("Unexpected abbrev ordering!");
3274   }
3275   { // INST_BINOP abbrev for FUNCTION_BLOCK.
3276     auto Abbv = std::make_shared<BitCodeAbbrev>();
3277     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3278     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3279     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3280     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3281     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3282         FUNCTION_INST_BINOP_ABBREV)
3283       llvm_unreachable("Unexpected abbrev ordering!");
3284   }
3285   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
3286     auto Abbv = std::make_shared<BitCodeAbbrev>();
3287     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3288     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3289     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3290     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3291     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3292     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3293         FUNCTION_INST_BINOP_FLAGS_ABBREV)
3294       llvm_unreachable("Unexpected abbrev ordering!");
3295   }
3296   { // INST_CAST abbrev for FUNCTION_BLOCK.
3297     auto Abbv = std::make_shared<BitCodeAbbrev>();
3298     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
3299     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
3300     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
3301                               VE.computeBitsRequiredForTypeIndicies()));
3302     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
3303     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3304         FUNCTION_INST_CAST_ABBREV)
3305       llvm_unreachable("Unexpected abbrev ordering!");
3306   }
3307 
3308   { // INST_RET abbrev for FUNCTION_BLOCK.
3309     auto Abbv = std::make_shared<BitCodeAbbrev>();
3310     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3311     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3312         FUNCTION_INST_RET_VOID_ABBREV)
3313       llvm_unreachable("Unexpected abbrev ordering!");
3314   }
3315   { // INST_RET abbrev for FUNCTION_BLOCK.
3316     auto Abbv = std::make_shared<BitCodeAbbrev>();
3317     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3318     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
3319     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3320         FUNCTION_INST_RET_VAL_ABBREV)
3321       llvm_unreachable("Unexpected abbrev ordering!");
3322   }
3323   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
3324     auto Abbv = std::make_shared<BitCodeAbbrev>();
3325     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
3326     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3327         FUNCTION_INST_UNREACHABLE_ABBREV)
3328       llvm_unreachable("Unexpected abbrev ordering!");
3329   }
3330   {
3331     auto Abbv = std::make_shared<BitCodeAbbrev>();
3332     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_GEP));
3333     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
3334     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, // dest ty
3335                               Log2_32_Ceil(VE.getTypes().size() + 1)));
3336     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3337     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
3338     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3339         FUNCTION_INST_GEP_ABBREV)
3340       llvm_unreachable("Unexpected abbrev ordering!");
3341   }
3342 
3343   Stream.ExitBlock();
3344 }
3345 
3346 /// Write the module path strings, currently only used when generating
3347 /// a combined index file.
3348 void IndexBitcodeWriter::writeModStrings() {
3349   Stream.EnterSubblock(bitc::MODULE_STRTAB_BLOCK_ID, 3);
3350 
3351   // TODO: See which abbrev sizes we actually need to emit
3352 
3353   // 8-bit fixed-width MST_ENTRY strings.
3354   auto Abbv = std::make_shared<BitCodeAbbrev>();
3355   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3356   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3357   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3358   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3359   unsigned Abbrev8Bit = Stream.EmitAbbrev(std::move(Abbv));
3360 
3361   // 7-bit fixed width MST_ENTRY strings.
3362   Abbv = std::make_shared<BitCodeAbbrev>();
3363   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3364   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3365   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3366   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3367   unsigned Abbrev7Bit = Stream.EmitAbbrev(std::move(Abbv));
3368 
3369   // 6-bit char6 MST_ENTRY strings.
3370   Abbv = std::make_shared<BitCodeAbbrev>();
3371   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3372   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3373   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3374   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3375   unsigned Abbrev6Bit = Stream.EmitAbbrev(std::move(Abbv));
3376 
3377   // Module Hash, 160 bits SHA1. Optionally, emitted after each MST_CODE_ENTRY.
3378   Abbv = std::make_shared<BitCodeAbbrev>();
3379   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_HASH));
3380   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3381   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3382   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3383   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3384   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3385   unsigned AbbrevHash = Stream.EmitAbbrev(std::move(Abbv));
3386 
3387   SmallVector<unsigned, 64> Vals;
3388   forEachModule(
3389       [&](const StringMapEntry<std::pair<uint64_t, ModuleHash>> &MPSE) {
3390         StringRef Key = MPSE.getKey();
3391         const auto &Value = MPSE.getValue();
3392         StringEncoding Bits = getStringEncoding(Key);
3393         unsigned AbbrevToUse = Abbrev8Bit;
3394         if (Bits == SE_Char6)
3395           AbbrevToUse = Abbrev6Bit;
3396         else if (Bits == SE_Fixed7)
3397           AbbrevToUse = Abbrev7Bit;
3398 
3399         Vals.push_back(Value.first);
3400         Vals.append(Key.begin(), Key.end());
3401 
3402         // Emit the finished record.
3403         Stream.EmitRecord(bitc::MST_CODE_ENTRY, Vals, AbbrevToUse);
3404 
3405         // Emit an optional hash for the module now
3406         const auto &Hash = Value.second;
3407         if (llvm::any_of(Hash, [](uint32_t H) { return H; })) {
3408           Vals.assign(Hash.begin(), Hash.end());
3409           // Emit the hash record.
3410           Stream.EmitRecord(bitc::MST_CODE_HASH, Vals, AbbrevHash);
3411         }
3412 
3413         Vals.clear();
3414       });
3415   Stream.ExitBlock();
3416 }
3417 
3418 /// Write the function type metadata related records that need to appear before
3419 /// a function summary entry (whether per-module or combined).
3420 static void writeFunctionTypeMetadataRecords(BitstreamWriter &Stream,
3421                                              FunctionSummary *FS) {
3422   if (!FS->type_tests().empty())
3423     Stream.EmitRecord(bitc::FS_TYPE_TESTS, FS->type_tests());
3424 
3425   SmallVector<uint64_t, 64> Record;
3426 
3427   auto WriteVFuncIdVec = [&](uint64_t Ty,
3428                              ArrayRef<FunctionSummary::VFuncId> VFs) {
3429     if (VFs.empty())
3430       return;
3431     Record.clear();
3432     for (auto &VF : VFs) {
3433       Record.push_back(VF.GUID);
3434       Record.push_back(VF.Offset);
3435     }
3436     Stream.EmitRecord(Ty, Record);
3437   };
3438 
3439   WriteVFuncIdVec(bitc::FS_TYPE_TEST_ASSUME_VCALLS,
3440                   FS->type_test_assume_vcalls());
3441   WriteVFuncIdVec(bitc::FS_TYPE_CHECKED_LOAD_VCALLS,
3442                   FS->type_checked_load_vcalls());
3443 
3444   auto WriteConstVCallVec = [&](uint64_t Ty,
3445                                 ArrayRef<FunctionSummary::ConstVCall> VCs) {
3446     for (auto &VC : VCs) {
3447       Record.clear();
3448       Record.push_back(VC.VFunc.GUID);
3449       Record.push_back(VC.VFunc.Offset);
3450       Record.insert(Record.end(), VC.Args.begin(), VC.Args.end());
3451       Stream.EmitRecord(Ty, Record);
3452     }
3453   };
3454 
3455   WriteConstVCallVec(bitc::FS_TYPE_TEST_ASSUME_CONST_VCALL,
3456                      FS->type_test_assume_const_vcalls());
3457   WriteConstVCallVec(bitc::FS_TYPE_CHECKED_LOAD_CONST_VCALL,
3458                      FS->type_checked_load_const_vcalls());
3459 }
3460 
3461 /// Collect type IDs from type tests used by function.
3462 static void
3463 getReferencedTypeIds(FunctionSummary *FS,
3464                      std::set<GlobalValue::GUID> &ReferencedTypeIds) {
3465   if (!FS->type_tests().empty())
3466     for (auto &TT : FS->type_tests())
3467       ReferencedTypeIds.insert(TT);
3468 
3469   auto GetReferencedTypesFromVFuncIdVec =
3470       [&](ArrayRef<FunctionSummary::VFuncId> VFs) {
3471         for (auto &VF : VFs)
3472           ReferencedTypeIds.insert(VF.GUID);
3473       };
3474 
3475   GetReferencedTypesFromVFuncIdVec(FS->type_test_assume_vcalls());
3476   GetReferencedTypesFromVFuncIdVec(FS->type_checked_load_vcalls());
3477 
3478   auto GetReferencedTypesFromConstVCallVec =
3479       [&](ArrayRef<FunctionSummary::ConstVCall> VCs) {
3480         for (auto &VC : VCs)
3481           ReferencedTypeIds.insert(VC.VFunc.GUID);
3482       };
3483 
3484   GetReferencedTypesFromConstVCallVec(FS->type_test_assume_const_vcalls());
3485   GetReferencedTypesFromConstVCallVec(FS->type_checked_load_const_vcalls());
3486 }
3487 
3488 static void writeWholeProgramDevirtResolutionByArg(
3489     SmallVector<uint64_t, 64> &NameVals, const std::vector<uint64_t> &args,
3490     const WholeProgramDevirtResolution::ByArg &ByArg) {
3491   NameVals.push_back(args.size());
3492   NameVals.insert(NameVals.end(), args.begin(), args.end());
3493 
3494   NameVals.push_back(ByArg.TheKind);
3495   NameVals.push_back(ByArg.Info);
3496   NameVals.push_back(ByArg.Byte);
3497   NameVals.push_back(ByArg.Bit);
3498 }
3499 
3500 static void writeWholeProgramDevirtResolution(
3501     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3502     uint64_t Id, const WholeProgramDevirtResolution &Wpd) {
3503   NameVals.push_back(Id);
3504 
3505   NameVals.push_back(Wpd.TheKind);
3506   NameVals.push_back(StrtabBuilder.add(Wpd.SingleImplName));
3507   NameVals.push_back(Wpd.SingleImplName.size());
3508 
3509   NameVals.push_back(Wpd.ResByArg.size());
3510   for (auto &A : Wpd.ResByArg)
3511     writeWholeProgramDevirtResolutionByArg(NameVals, A.first, A.second);
3512 }
3513 
3514 static void writeTypeIdSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
3515                                      StringTableBuilder &StrtabBuilder,
3516                                      const std::string &Id,
3517                                      const TypeIdSummary &Summary) {
3518   NameVals.push_back(StrtabBuilder.add(Id));
3519   NameVals.push_back(Id.size());
3520 
3521   NameVals.push_back(Summary.TTRes.TheKind);
3522   NameVals.push_back(Summary.TTRes.SizeM1BitWidth);
3523   NameVals.push_back(Summary.TTRes.AlignLog2);
3524   NameVals.push_back(Summary.TTRes.SizeM1);
3525   NameVals.push_back(Summary.TTRes.BitMask);
3526   NameVals.push_back(Summary.TTRes.InlineBits);
3527 
3528   for (auto &W : Summary.WPDRes)
3529     writeWholeProgramDevirtResolution(NameVals, StrtabBuilder, W.first,
3530                                       W.second);
3531 }
3532 
3533 // Helper to emit a single function summary record.
3534 void ModuleBitcodeWriterBase::writePerModuleFunctionSummaryRecord(
3535     SmallVector<uint64_t, 64> &NameVals, GlobalValueSummary *Summary,
3536     unsigned ValueID, unsigned FSCallsAbbrev, unsigned FSCallsProfileAbbrev,
3537     const Function &F) {
3538   NameVals.push_back(ValueID);
3539 
3540   FunctionSummary *FS = cast<FunctionSummary>(Summary);
3541   writeFunctionTypeMetadataRecords(Stream, FS);
3542 
3543   NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
3544   NameVals.push_back(FS->instCount());
3545   NameVals.push_back(getEncodedFFlags(FS->fflags()));
3546   NameVals.push_back(FS->refs().size());
3547   NameVals.push_back(FS->immutableRefCount());
3548 
3549   for (auto &RI : FS->refs())
3550     NameVals.push_back(VE.getValueID(RI.getValue()));
3551 
3552   bool HasProfileData =
3553       F.hasProfileData() || ForceSummaryEdgesCold != FunctionSummary::FSHT_None;
3554   for (auto &ECI : FS->calls()) {
3555     NameVals.push_back(getValueId(ECI.first));
3556     if (HasProfileData)
3557       NameVals.push_back(static_cast<uint8_t>(ECI.second.Hotness));
3558     else if (WriteRelBFToSummary)
3559       NameVals.push_back(ECI.second.RelBlockFreq);
3560   }
3561 
3562   unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
3563   unsigned Code =
3564       (HasProfileData ? bitc::FS_PERMODULE_PROFILE
3565                       : (WriteRelBFToSummary ? bitc::FS_PERMODULE_RELBF
3566                                              : bitc::FS_PERMODULE));
3567 
3568   // Emit the finished record.
3569   Stream.EmitRecord(Code, NameVals, FSAbbrev);
3570   NameVals.clear();
3571 }
3572 
3573 // Collect the global value references in the given variable's initializer,
3574 // and emit them in a summary record.
3575 void ModuleBitcodeWriterBase::writeModuleLevelReferences(
3576     const GlobalVariable &V, SmallVector<uint64_t, 64> &NameVals,
3577     unsigned FSModRefsAbbrev) {
3578   auto VI = Index->getValueInfo(V.getGUID());
3579   if (!VI || VI.getSummaryList().empty()) {
3580     // Only declarations should not have a summary (a declaration might however
3581     // have a summary if the def was in module level asm).
3582     assert(V.isDeclaration());
3583     return;
3584   }
3585   auto *Summary = VI.getSummaryList()[0].get();
3586   NameVals.push_back(VE.getValueID(&V));
3587   GlobalVarSummary *VS = cast<GlobalVarSummary>(Summary);
3588   NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
3589   NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
3590 
3591   unsigned SizeBeforeRefs = NameVals.size();
3592   for (auto &RI : VS->refs())
3593     NameVals.push_back(VE.getValueID(RI.getValue()));
3594   // Sort the refs for determinism output, the vector returned by FS->refs() has
3595   // been initialized from a DenseSet.
3596   llvm::sort(NameVals.begin() + SizeBeforeRefs, NameVals.end());
3597 
3598   Stream.EmitRecord(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS, NameVals,
3599                     FSModRefsAbbrev);
3600   NameVals.clear();
3601 }
3602 
3603 // Current version for the summary.
3604 // This is bumped whenever we introduce changes in the way some record are
3605 // interpreted, like flags for instance.
3606 static const uint64_t INDEX_VERSION = 5;
3607 
3608 /// Emit the per-module summary section alongside the rest of
3609 /// the module's bitcode.
3610 void ModuleBitcodeWriterBase::writePerModuleGlobalValueSummary() {
3611   // By default we compile with ThinLTO if the module has a summary, but the
3612   // client can request full LTO with a module flag.
3613   bool IsThinLTO = true;
3614   if (auto *MD =
3615           mdconst::extract_or_null<ConstantInt>(M.getModuleFlag("ThinLTO")))
3616     IsThinLTO = MD->getZExtValue();
3617   Stream.EnterSubblock(IsThinLTO ? bitc::GLOBALVAL_SUMMARY_BLOCK_ID
3618                                  : bitc::FULL_LTO_GLOBALVAL_SUMMARY_BLOCK_ID,
3619                        4);
3620 
3621   Stream.EmitRecord(bitc::FS_VERSION, ArrayRef<uint64_t>{INDEX_VERSION});
3622 
3623   if (Index->begin() == Index->end()) {
3624     Stream.ExitBlock();
3625     return;
3626   }
3627 
3628   for (const auto &GVI : valueIds()) {
3629     Stream.EmitRecord(bitc::FS_VALUE_GUID,
3630                       ArrayRef<uint64_t>{GVI.second, GVI.first});
3631   }
3632 
3633   // Abbrev for FS_PERMODULE_PROFILE.
3634   auto Abbv = std::make_shared<BitCodeAbbrev>();
3635   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_PROFILE));
3636   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3637   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3638   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3639   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3640   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3641   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // immutablerefcnt
3642   // numrefs x valueid, n x (valueid, hotness)
3643   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3644   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3645   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3646 
3647   // Abbrev for FS_PERMODULE or FS_PERMODULE_RELBF.
3648   Abbv = std::make_shared<BitCodeAbbrev>();
3649   if (WriteRelBFToSummary)
3650     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_RELBF));
3651   else
3652     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE));
3653   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3654   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3655   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3656   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3657   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3658   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // immutablerefcnt
3659   // numrefs x valueid, n x (valueid [, rel_block_freq])
3660   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3661   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3662   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3663 
3664   // Abbrev for FS_PERMODULE_GLOBALVAR_INIT_REFS.
3665   Abbv = std::make_shared<BitCodeAbbrev>();
3666   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS));
3667   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
3668   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
3669   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));  // valueids
3670   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3671   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3672 
3673   // Abbrev for FS_ALIAS.
3674   Abbv = std::make_shared<BitCodeAbbrev>();
3675   Abbv->Add(BitCodeAbbrevOp(bitc::FS_ALIAS));
3676   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3677   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3678   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3679   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3680 
3681   SmallVector<uint64_t, 64> NameVals;
3682   // Iterate over the list of functions instead of the Index to
3683   // ensure the ordering is stable.
3684   for (const Function &F : M) {
3685     // Summary emission does not support anonymous functions, they have to
3686     // renamed using the anonymous function renaming pass.
3687     if (!F.hasName())
3688       report_fatal_error("Unexpected anonymous function when writing summary");
3689 
3690     ValueInfo VI = Index->getValueInfo(F.getGUID());
3691     if (!VI || VI.getSummaryList().empty()) {
3692       // Only declarations should not have a summary (a declaration might
3693       // however have a summary if the def was in module level asm).
3694       assert(F.isDeclaration());
3695       continue;
3696     }
3697     auto *Summary = VI.getSummaryList()[0].get();
3698     writePerModuleFunctionSummaryRecord(NameVals, Summary, VE.getValueID(&F),
3699                                         FSCallsAbbrev, FSCallsProfileAbbrev, F);
3700   }
3701 
3702   // Capture references from GlobalVariable initializers, which are outside
3703   // of a function scope.
3704   for (const GlobalVariable &G : M.globals())
3705     writeModuleLevelReferences(G, NameVals, FSModRefsAbbrev);
3706 
3707   for (const GlobalAlias &A : M.aliases()) {
3708     auto *Aliasee = A.getBaseObject();
3709     if (!Aliasee->hasName())
3710       // Nameless function don't have an entry in the summary, skip it.
3711       continue;
3712     auto AliasId = VE.getValueID(&A);
3713     auto AliaseeId = VE.getValueID(Aliasee);
3714     NameVals.push_back(AliasId);
3715     auto *Summary = Index->getGlobalValueSummary(A);
3716     AliasSummary *AS = cast<AliasSummary>(Summary);
3717     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
3718     NameVals.push_back(AliaseeId);
3719     Stream.EmitRecord(bitc::FS_ALIAS, NameVals, FSAliasAbbrev);
3720     NameVals.clear();
3721   }
3722 
3723   Stream.ExitBlock();
3724 }
3725 
3726 /// Emit the combined summary section into the combined index file.
3727 void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
3728   Stream.EnterSubblock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID, 3);
3729   Stream.EmitRecord(bitc::FS_VERSION, ArrayRef<uint64_t>{INDEX_VERSION});
3730 
3731   // Write the index flags.
3732   uint64_t Flags = 0;
3733   if (Index.withGlobalValueDeadStripping())
3734     Flags |= 0x1;
3735   if (Index.skipModuleByDistributedBackend())
3736     Flags |= 0x2;
3737   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Flags});
3738 
3739   for (const auto &GVI : valueIds()) {
3740     Stream.EmitRecord(bitc::FS_VALUE_GUID,
3741                       ArrayRef<uint64_t>{GVI.second, GVI.first});
3742   }
3743 
3744   // Abbrev for FS_COMBINED.
3745   auto Abbv = std::make_shared<BitCodeAbbrev>();
3746   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED));
3747   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3748   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3749   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3750   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3751   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3752   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3753   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // immutablerefcnt
3754   // numrefs x valueid, n x (valueid)
3755   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3756   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3757   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3758 
3759   // Abbrev for FS_COMBINED_PROFILE.
3760   Abbv = std::make_shared<BitCodeAbbrev>();
3761   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_PROFILE));
3762   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3763   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3764   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3765   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3766   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3767   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3768   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // immutablerefcnt
3769   // numrefs x valueid, n x (valueid, hotness)
3770   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3771   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3772   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3773 
3774   // Abbrev for FS_COMBINED_GLOBALVAR_INIT_REFS.
3775   Abbv = std::make_shared<BitCodeAbbrev>();
3776   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS));
3777   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3778   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3779   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3780   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));    // valueids
3781   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3782   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3783 
3784   // Abbrev for FS_COMBINED_ALIAS.
3785   Abbv = std::make_shared<BitCodeAbbrev>();
3786   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_ALIAS));
3787   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3788   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3789   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3790   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3791   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3792 
3793   // The aliases are emitted as a post-pass, and will point to the value
3794   // id of the aliasee. Save them in a vector for post-processing.
3795   SmallVector<AliasSummary *, 64> Aliases;
3796 
3797   // Save the value id for each summary for alias emission.
3798   DenseMap<const GlobalValueSummary *, unsigned> SummaryToValueIdMap;
3799 
3800   SmallVector<uint64_t, 64> NameVals;
3801 
3802   // Set that will be populated during call to writeFunctionTypeMetadataRecords
3803   // with the type ids referenced by this index file.
3804   std::set<GlobalValue::GUID> ReferencedTypeIds;
3805 
3806   // For local linkage, we also emit the original name separately
3807   // immediately after the record.
3808   auto MaybeEmitOriginalName = [&](GlobalValueSummary &S) {
3809     if (!GlobalValue::isLocalLinkage(S.linkage()))
3810       return;
3811     NameVals.push_back(S.getOriginalName());
3812     Stream.EmitRecord(bitc::FS_COMBINED_ORIGINAL_NAME, NameVals);
3813     NameVals.clear();
3814   };
3815 
3816   forEachSummary([&](GVInfo I, bool IsAliasee) {
3817     GlobalValueSummary *S = I.second;
3818     assert(S);
3819 
3820     auto ValueId = getValueId(I.first);
3821     assert(ValueId);
3822     SummaryToValueIdMap[S] = *ValueId;
3823 
3824     // If this is invoked for an aliasee, we want to record the above
3825     // mapping, but then not emit a summary entry (if the aliasee is
3826     // to be imported, we will invoke this separately with IsAliasee=false).
3827     if (IsAliasee)
3828       return;
3829 
3830     if (auto *AS = dyn_cast<AliasSummary>(S)) {
3831       // Will process aliases as a post-pass because the reader wants all
3832       // global to be loaded first.
3833       Aliases.push_back(AS);
3834       return;
3835     }
3836 
3837     if (auto *VS = dyn_cast<GlobalVarSummary>(S)) {
3838       NameVals.push_back(*ValueId);
3839       NameVals.push_back(Index.getModuleId(VS->modulePath()));
3840       NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
3841       NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
3842       for (auto &RI : VS->refs()) {
3843         auto RefValueId = getValueId(RI.getGUID());
3844         if (!RefValueId)
3845           continue;
3846         NameVals.push_back(*RefValueId);
3847       }
3848 
3849       // Emit the finished record.
3850       Stream.EmitRecord(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS, NameVals,
3851                         FSModRefsAbbrev);
3852       NameVals.clear();
3853       MaybeEmitOriginalName(*S);
3854       return;
3855     }
3856 
3857     auto *FS = cast<FunctionSummary>(S);
3858     writeFunctionTypeMetadataRecords(Stream, FS);
3859     getReferencedTypeIds(FS, ReferencedTypeIds);
3860 
3861     NameVals.push_back(*ValueId);
3862     NameVals.push_back(Index.getModuleId(FS->modulePath()));
3863     NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
3864     NameVals.push_back(FS->instCount());
3865     NameVals.push_back(getEncodedFFlags(FS->fflags()));
3866     // Fill in below
3867     NameVals.push_back(0); // numrefs
3868     NameVals.push_back(0); // immutablerefcnt
3869 
3870     unsigned Count = 0, ImmutableRefCnt = 0;
3871     for (auto &RI : FS->refs()) {
3872       auto RefValueId = getValueId(RI.getGUID());
3873       if (!RefValueId)
3874         continue;
3875       NameVals.push_back(*RefValueId);
3876       if (RI.isReadOnly())
3877         ImmutableRefCnt++;
3878       Count++;
3879     }
3880     NameVals[5] = Count;
3881     NameVals[6] = ImmutableRefCnt;
3882 
3883     bool HasProfileData = false;
3884     for (auto &EI : FS->calls()) {
3885       HasProfileData |=
3886           EI.second.getHotness() != CalleeInfo::HotnessType::Unknown;
3887       if (HasProfileData)
3888         break;
3889     }
3890 
3891     for (auto &EI : FS->calls()) {
3892       // If this GUID doesn't have a value id, it doesn't have a function
3893       // summary and we don't need to record any calls to it.
3894       GlobalValue::GUID GUID = EI.first.getGUID();
3895       auto CallValueId = getValueId(GUID);
3896       if (!CallValueId) {
3897         // For SamplePGO, the indirect call targets for local functions will
3898         // have its original name annotated in profile. We try to find the
3899         // corresponding PGOFuncName as the GUID.
3900         GUID = Index.getGUIDFromOriginalID(GUID);
3901         if (GUID == 0)
3902           continue;
3903         CallValueId = getValueId(GUID);
3904         if (!CallValueId)
3905           continue;
3906         // The mapping from OriginalId to GUID may return a GUID
3907         // that corresponds to a static variable. Filter it out here.
3908         // This can happen when
3909         // 1) There is a call to a library function which does not have
3910         // a CallValidId;
3911         // 2) There is a static variable with the  OriginalGUID identical
3912         // to the GUID of the library function in 1);
3913         // When this happens, the logic for SamplePGO kicks in and
3914         // the static variable in 2) will be found, which needs to be
3915         // filtered out.
3916         auto *GVSum = Index.getGlobalValueSummary(GUID, false);
3917         if (GVSum &&
3918             GVSum->getSummaryKind() == GlobalValueSummary::GlobalVarKind)
3919           continue;
3920       }
3921       NameVals.push_back(*CallValueId);
3922       if (HasProfileData)
3923         NameVals.push_back(static_cast<uint8_t>(EI.second.Hotness));
3924     }
3925 
3926     unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
3927     unsigned Code =
3928         (HasProfileData ? bitc::FS_COMBINED_PROFILE : bitc::FS_COMBINED);
3929 
3930     // Emit the finished record.
3931     Stream.EmitRecord(Code, NameVals, FSAbbrev);
3932     NameVals.clear();
3933     MaybeEmitOriginalName(*S);
3934   });
3935 
3936   for (auto *AS : Aliases) {
3937     auto AliasValueId = SummaryToValueIdMap[AS];
3938     assert(AliasValueId);
3939     NameVals.push_back(AliasValueId);
3940     NameVals.push_back(Index.getModuleId(AS->modulePath()));
3941     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
3942     auto AliaseeValueId = SummaryToValueIdMap[&AS->getAliasee()];
3943     assert(AliaseeValueId);
3944     NameVals.push_back(AliaseeValueId);
3945 
3946     // Emit the finished record.
3947     Stream.EmitRecord(bitc::FS_COMBINED_ALIAS, NameVals, FSAliasAbbrev);
3948     NameVals.clear();
3949     MaybeEmitOriginalName(*AS);
3950 
3951     if (auto *FS = dyn_cast<FunctionSummary>(&AS->getAliasee()))
3952       getReferencedTypeIds(FS, ReferencedTypeIds);
3953   }
3954 
3955   if (!Index.cfiFunctionDefs().empty()) {
3956     for (auto &S : Index.cfiFunctionDefs()) {
3957       NameVals.push_back(StrtabBuilder.add(S));
3958       NameVals.push_back(S.size());
3959     }
3960     Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DEFS, NameVals);
3961     NameVals.clear();
3962   }
3963 
3964   if (!Index.cfiFunctionDecls().empty()) {
3965     for (auto &S : Index.cfiFunctionDecls()) {
3966       NameVals.push_back(StrtabBuilder.add(S));
3967       NameVals.push_back(S.size());
3968     }
3969     Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DECLS, NameVals);
3970     NameVals.clear();
3971   }
3972 
3973   // Walk the GUIDs that were referenced, and write the
3974   // corresponding type id records.
3975   for (auto &T : ReferencedTypeIds) {
3976     auto TidIter = Index.typeIds().equal_range(T);
3977     for (auto It = TidIter.first; It != TidIter.second; ++It) {
3978       writeTypeIdSummaryRecord(NameVals, StrtabBuilder, It->second.first,
3979                                It->second.second);
3980       Stream.EmitRecord(bitc::FS_TYPE_ID, NameVals);
3981       NameVals.clear();
3982     }
3983   }
3984 
3985   Stream.ExitBlock();
3986 }
3987 
3988 /// Create the "IDENTIFICATION_BLOCK_ID" containing a single string with the
3989 /// current llvm version, and a record for the epoch number.
3990 static void writeIdentificationBlock(BitstreamWriter &Stream) {
3991   Stream.EnterSubblock(bitc::IDENTIFICATION_BLOCK_ID, 5);
3992 
3993   // Write the "user readable" string identifying the bitcode producer
3994   auto Abbv = std::make_shared<BitCodeAbbrev>();
3995   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_STRING));
3996   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3997   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3998   auto StringAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3999   writeStringRecord(Stream, bitc::IDENTIFICATION_CODE_STRING,
4000                     "LLVM" LLVM_VERSION_STRING, StringAbbrev);
4001 
4002   // Write the epoch version
4003   Abbv = std::make_shared<BitCodeAbbrev>();
4004   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_EPOCH));
4005   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
4006   auto EpochAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4007   SmallVector<unsigned, 1> Vals = {bitc::BITCODE_CURRENT_EPOCH};
4008   Stream.EmitRecord(bitc::IDENTIFICATION_CODE_EPOCH, Vals, EpochAbbrev);
4009   Stream.ExitBlock();
4010 }
4011 
4012 void ModuleBitcodeWriter::writeModuleHash(size_t BlockStartPos) {
4013   // Emit the module's hash.
4014   // MODULE_CODE_HASH: [5*i32]
4015   if (GenerateHash) {
4016     uint32_t Vals[5];
4017     Hasher.update(ArrayRef<uint8_t>((const uint8_t *)&(Buffer)[BlockStartPos],
4018                                     Buffer.size() - BlockStartPos));
4019     StringRef Hash = Hasher.result();
4020     for (int Pos = 0; Pos < 20; Pos += 4) {
4021       Vals[Pos / 4] = support::endian::read32be(Hash.data() + Pos);
4022     }
4023 
4024     // Emit the finished record.
4025     Stream.EmitRecord(bitc::MODULE_CODE_HASH, Vals);
4026 
4027     if (ModHash)
4028       // Save the written hash value.
4029       std::copy(std::begin(Vals), std::end(Vals), std::begin(*ModHash));
4030   }
4031 }
4032 
4033 void ModuleBitcodeWriter::write() {
4034   writeIdentificationBlock(Stream);
4035 
4036   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4037   size_t BlockStartPos = Buffer.size();
4038 
4039   writeModuleVersion();
4040 
4041   // Emit blockinfo, which defines the standard abbreviations etc.
4042   writeBlockInfo();
4043 
4044   // Emit information about attribute groups.
4045   writeAttributeGroupTable();
4046 
4047   // Emit information about parameter attributes.
4048   writeAttributeTable();
4049 
4050   // Emit information describing all of the types in the module.
4051   writeTypeTable();
4052 
4053   writeComdats();
4054 
4055   // Emit top-level description of module, including target triple, inline asm,
4056   // descriptors for global variables, and function prototype info.
4057   writeModuleInfo();
4058 
4059   // Emit constants.
4060   writeModuleConstants();
4061 
4062   // Emit metadata kind names.
4063   writeModuleMetadataKinds();
4064 
4065   // Emit metadata.
4066   writeModuleMetadata();
4067 
4068   // Emit module-level use-lists.
4069   if (VE.shouldPreserveUseListOrder())
4070     writeUseListBlock(nullptr);
4071 
4072   writeOperandBundleTags();
4073   writeSyncScopeNames();
4074 
4075   // Emit function bodies.
4076   DenseMap<const Function *, uint64_t> FunctionToBitcodeIndex;
4077   for (Module::const_iterator F = M.begin(), E = M.end(); F != E; ++F)
4078     if (!F->isDeclaration())
4079       writeFunction(*F, FunctionToBitcodeIndex);
4080 
4081   // Need to write after the above call to WriteFunction which populates
4082   // the summary information in the index.
4083   if (Index)
4084     writePerModuleGlobalValueSummary();
4085 
4086   writeGlobalValueSymbolTable(FunctionToBitcodeIndex);
4087 
4088   writeModuleHash(BlockStartPos);
4089 
4090   Stream.ExitBlock();
4091 }
4092 
4093 static void writeInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
4094                                uint32_t &Position) {
4095   support::endian::write32le(&Buffer[Position], Value);
4096   Position += 4;
4097 }
4098 
4099 /// If generating a bc file on darwin, we have to emit a
4100 /// header and trailer to make it compatible with the system archiver.  To do
4101 /// this we emit the following header, and then emit a trailer that pads the
4102 /// file out to be a multiple of 16 bytes.
4103 ///
4104 /// struct bc_header {
4105 ///   uint32_t Magic;         // 0x0B17C0DE
4106 ///   uint32_t Version;       // Version, currently always 0.
4107 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
4108 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
4109 ///   uint32_t CPUType;       // CPU specifier.
4110 ///   ... potentially more later ...
4111 /// };
4112 static void emitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
4113                                          const Triple &TT) {
4114   unsigned CPUType = ~0U;
4115 
4116   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
4117   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
4118   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
4119   // specific constants here because they are implicitly part of the Darwin ABI.
4120   enum {
4121     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
4122     DARWIN_CPU_TYPE_X86        = 7,
4123     DARWIN_CPU_TYPE_ARM        = 12,
4124     DARWIN_CPU_TYPE_POWERPC    = 18
4125   };
4126 
4127   Triple::ArchType Arch = TT.getArch();
4128   if (Arch == Triple::x86_64)
4129     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
4130   else if (Arch == Triple::x86)
4131     CPUType = DARWIN_CPU_TYPE_X86;
4132   else if (Arch == Triple::ppc)
4133     CPUType = DARWIN_CPU_TYPE_POWERPC;
4134   else if (Arch == Triple::ppc64)
4135     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
4136   else if (Arch == Triple::arm || Arch == Triple::thumb)
4137     CPUType = DARWIN_CPU_TYPE_ARM;
4138 
4139   // Traditional Bitcode starts after header.
4140   assert(Buffer.size() >= BWH_HeaderSize &&
4141          "Expected header size to be reserved");
4142   unsigned BCOffset = BWH_HeaderSize;
4143   unsigned BCSize = Buffer.size() - BWH_HeaderSize;
4144 
4145   // Write the magic and version.
4146   unsigned Position = 0;
4147   writeInt32ToBuffer(0x0B17C0DE, Buffer, Position);
4148   writeInt32ToBuffer(0, Buffer, Position); // Version.
4149   writeInt32ToBuffer(BCOffset, Buffer, Position);
4150   writeInt32ToBuffer(BCSize, Buffer, Position);
4151   writeInt32ToBuffer(CPUType, Buffer, Position);
4152 
4153   // If the file is not a multiple of 16 bytes, insert dummy padding.
4154   while (Buffer.size() & 15)
4155     Buffer.push_back(0);
4156 }
4157 
4158 /// Helper to write the header common to all bitcode files.
4159 static void writeBitcodeHeader(BitstreamWriter &Stream) {
4160   // Emit the file header.
4161   Stream.Emit((unsigned)'B', 8);
4162   Stream.Emit((unsigned)'C', 8);
4163   Stream.Emit(0x0, 4);
4164   Stream.Emit(0xC, 4);
4165   Stream.Emit(0xE, 4);
4166   Stream.Emit(0xD, 4);
4167 }
4168 
4169 BitcodeWriter::BitcodeWriter(SmallVectorImpl<char> &Buffer)
4170     : Buffer(Buffer), Stream(new BitstreamWriter(Buffer)) {
4171   writeBitcodeHeader(*Stream);
4172 }
4173 
4174 BitcodeWriter::~BitcodeWriter() { assert(WroteStrtab); }
4175 
4176 void BitcodeWriter::writeBlob(unsigned Block, unsigned Record, StringRef Blob) {
4177   Stream->EnterSubblock(Block, 3);
4178 
4179   auto Abbv = std::make_shared<BitCodeAbbrev>();
4180   Abbv->Add(BitCodeAbbrevOp(Record));
4181   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
4182   auto AbbrevNo = Stream->EmitAbbrev(std::move(Abbv));
4183 
4184   Stream->EmitRecordWithBlob(AbbrevNo, ArrayRef<uint64_t>{Record}, Blob);
4185 
4186   Stream->ExitBlock();
4187 }
4188 
4189 void BitcodeWriter::writeSymtab() {
4190   assert(!WroteStrtab && !WroteSymtab);
4191 
4192   // If any module has module-level inline asm, we will require a registered asm
4193   // parser for the target so that we can create an accurate symbol table for
4194   // the module.
4195   for (Module *M : Mods) {
4196     if (M->getModuleInlineAsm().empty())
4197       continue;
4198 
4199     std::string Err;
4200     const Triple TT(M->getTargetTriple());
4201     const Target *T = TargetRegistry::lookupTarget(TT.str(), Err);
4202     if (!T || !T->hasMCAsmParser())
4203       return;
4204   }
4205 
4206   WroteSymtab = true;
4207   SmallVector<char, 0> Symtab;
4208   // The irsymtab::build function may be unable to create a symbol table if the
4209   // module is malformed (e.g. it contains an invalid alias). Writing a symbol
4210   // table is not required for correctness, but we still want to be able to
4211   // write malformed modules to bitcode files, so swallow the error.
4212   if (Error E = irsymtab::build(Mods, Symtab, StrtabBuilder, Alloc)) {
4213     consumeError(std::move(E));
4214     return;
4215   }
4216 
4217   writeBlob(bitc::SYMTAB_BLOCK_ID, bitc::SYMTAB_BLOB,
4218             {Symtab.data(), Symtab.size()});
4219 }
4220 
4221 void BitcodeWriter::writeStrtab() {
4222   assert(!WroteStrtab);
4223 
4224   std::vector<char> Strtab;
4225   StrtabBuilder.finalizeInOrder();
4226   Strtab.resize(StrtabBuilder.getSize());
4227   StrtabBuilder.write((uint8_t *)Strtab.data());
4228 
4229   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB,
4230             {Strtab.data(), Strtab.size()});
4231 
4232   WroteStrtab = true;
4233 }
4234 
4235 void BitcodeWriter::copyStrtab(StringRef Strtab) {
4236   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB, Strtab);
4237   WroteStrtab = true;
4238 }
4239 
4240 void BitcodeWriter::writeModule(const Module &M,
4241                                 bool ShouldPreserveUseListOrder,
4242                                 const ModuleSummaryIndex *Index,
4243                                 bool GenerateHash, ModuleHash *ModHash) {
4244   assert(!WroteStrtab);
4245 
4246   // The Mods vector is used by irsymtab::build, which requires non-const
4247   // Modules in case it needs to materialize metadata. But the bitcode writer
4248   // requires that the module is materialized, so we can cast to non-const here,
4249   // after checking that it is in fact materialized.
4250   assert(M.isMaterialized());
4251   Mods.push_back(const_cast<Module *>(&M));
4252 
4253   ModuleBitcodeWriter ModuleWriter(M, Buffer, StrtabBuilder, *Stream,
4254                                    ShouldPreserveUseListOrder, Index,
4255                                    GenerateHash, ModHash);
4256   ModuleWriter.write();
4257 }
4258 
4259 void BitcodeWriter::writeIndex(
4260     const ModuleSummaryIndex *Index,
4261     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4262   IndexBitcodeWriter IndexWriter(*Stream, StrtabBuilder, *Index,
4263                                  ModuleToSummariesForIndex);
4264   IndexWriter.write();
4265 }
4266 
4267 /// Write the specified module to the specified output stream.
4268 void llvm::WriteBitcodeToFile(const Module &M, raw_ostream &Out,
4269                               bool ShouldPreserveUseListOrder,
4270                               const ModuleSummaryIndex *Index,
4271                               bool GenerateHash, ModuleHash *ModHash) {
4272   SmallVector<char, 0> Buffer;
4273   Buffer.reserve(256*1024);
4274 
4275   // If this is darwin or another generic macho target, reserve space for the
4276   // header.
4277   Triple TT(M.getTargetTriple());
4278   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4279     Buffer.insert(Buffer.begin(), BWH_HeaderSize, 0);
4280 
4281   BitcodeWriter Writer(Buffer);
4282   Writer.writeModule(M, ShouldPreserveUseListOrder, Index, GenerateHash,
4283                      ModHash);
4284   Writer.writeSymtab();
4285   Writer.writeStrtab();
4286 
4287   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4288     emitDarwinBCHeaderAndTrailer(Buffer, TT);
4289 
4290   // Write the generated bitstream to "Out".
4291   Out.write((char*)&Buffer.front(), Buffer.size());
4292 }
4293 
4294 void IndexBitcodeWriter::write() {
4295   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4296 
4297   writeModuleVersion();
4298 
4299   // Write the module paths in the combined index.
4300   writeModStrings();
4301 
4302   // Write the summary combined index records.
4303   writeCombinedGlobalValueSummary();
4304 
4305   Stream.ExitBlock();
4306 }
4307 
4308 // Write the specified module summary index to the given raw output stream,
4309 // where it will be written in a new bitcode block. This is used when
4310 // writing the combined index file for ThinLTO. When writing a subset of the
4311 // index for a distributed backend, provide a \p ModuleToSummariesForIndex map.
4312 void llvm::WriteIndexToFile(
4313     const ModuleSummaryIndex &Index, raw_ostream &Out,
4314     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4315   SmallVector<char, 0> Buffer;
4316   Buffer.reserve(256 * 1024);
4317 
4318   BitcodeWriter Writer(Buffer);
4319   Writer.writeIndex(&Index, ModuleToSummariesForIndex);
4320   Writer.writeStrtab();
4321 
4322   Out.write((char *)&Buffer.front(), Buffer.size());
4323 }
4324 
4325 namespace {
4326 
4327 /// Class to manage the bitcode writing for a thin link bitcode file.
4328 class ThinLinkBitcodeWriter : public ModuleBitcodeWriterBase {
4329   /// ModHash is for use in ThinLTO incremental build, generated while writing
4330   /// the module bitcode file.
4331   const ModuleHash *ModHash;
4332 
4333 public:
4334   ThinLinkBitcodeWriter(const Module &M, StringTableBuilder &StrtabBuilder,
4335                         BitstreamWriter &Stream,
4336                         const ModuleSummaryIndex &Index,
4337                         const ModuleHash &ModHash)
4338       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
4339                                 /*ShouldPreserveUseListOrder=*/false, &Index),
4340         ModHash(&ModHash) {}
4341 
4342   void write();
4343 
4344 private:
4345   void writeSimplifiedModuleInfo();
4346 };
4347 
4348 } // end anonymous namespace
4349 
4350 // This function writes a simpilified module info for thin link bitcode file.
4351 // It only contains the source file name along with the name(the offset and
4352 // size in strtab) and linkage for global values. For the global value info
4353 // entry, in order to keep linkage at offset 5, there are three zeros used
4354 // as padding.
4355 void ThinLinkBitcodeWriter::writeSimplifiedModuleInfo() {
4356   SmallVector<unsigned, 64> Vals;
4357   // Emit the module's source file name.
4358   {
4359     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
4360     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
4361     if (Bits == SE_Char6)
4362       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
4363     else if (Bits == SE_Fixed7)
4364       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
4365 
4366     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
4367     auto Abbv = std::make_shared<BitCodeAbbrev>();
4368     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
4369     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4370     Abbv->Add(AbbrevOpToUse);
4371     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4372 
4373     for (const auto P : M.getSourceFileName())
4374       Vals.push_back((unsigned char)P);
4375 
4376     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
4377     Vals.clear();
4378   }
4379 
4380   // Emit the global variable information.
4381   for (const GlobalVariable &GV : M.globals()) {
4382     // GLOBALVAR: [strtab offset, strtab size, 0, 0, 0, linkage]
4383     Vals.push_back(StrtabBuilder.add(GV.getName()));
4384     Vals.push_back(GV.getName().size());
4385     Vals.push_back(0);
4386     Vals.push_back(0);
4387     Vals.push_back(0);
4388     Vals.push_back(getEncodedLinkage(GV));
4389 
4390     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals);
4391     Vals.clear();
4392   }
4393 
4394   // Emit the function proto information.
4395   for (const Function &F : M) {
4396     // FUNCTION:  [strtab offset, strtab size, 0, 0, 0, linkage]
4397     Vals.push_back(StrtabBuilder.add(F.getName()));
4398     Vals.push_back(F.getName().size());
4399     Vals.push_back(0);
4400     Vals.push_back(0);
4401     Vals.push_back(0);
4402     Vals.push_back(getEncodedLinkage(F));
4403 
4404     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals);
4405     Vals.clear();
4406   }
4407 
4408   // Emit the alias information.
4409   for (const GlobalAlias &A : M.aliases()) {
4410     // ALIAS: [strtab offset, strtab size, 0, 0, 0, linkage]
4411     Vals.push_back(StrtabBuilder.add(A.getName()));
4412     Vals.push_back(A.getName().size());
4413     Vals.push_back(0);
4414     Vals.push_back(0);
4415     Vals.push_back(0);
4416     Vals.push_back(getEncodedLinkage(A));
4417 
4418     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals);
4419     Vals.clear();
4420   }
4421 
4422   // Emit the ifunc information.
4423   for (const GlobalIFunc &I : M.ifuncs()) {
4424     // IFUNC: [strtab offset, strtab size, 0, 0, 0, linkage]
4425     Vals.push_back(StrtabBuilder.add(I.getName()));
4426     Vals.push_back(I.getName().size());
4427     Vals.push_back(0);
4428     Vals.push_back(0);
4429     Vals.push_back(0);
4430     Vals.push_back(getEncodedLinkage(I));
4431 
4432     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
4433     Vals.clear();
4434   }
4435 }
4436 
4437 void ThinLinkBitcodeWriter::write() {
4438   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4439 
4440   writeModuleVersion();
4441 
4442   writeSimplifiedModuleInfo();
4443 
4444   writePerModuleGlobalValueSummary();
4445 
4446   // Write module hash.
4447   Stream.EmitRecord(bitc::MODULE_CODE_HASH, ArrayRef<uint32_t>(*ModHash));
4448 
4449   Stream.ExitBlock();
4450 }
4451 
4452 void BitcodeWriter::writeThinLinkBitcode(const Module &M,
4453                                          const ModuleSummaryIndex &Index,
4454                                          const ModuleHash &ModHash) {
4455   assert(!WroteStrtab);
4456 
4457   // The Mods vector is used by irsymtab::build, which requires non-const
4458   // Modules in case it needs to materialize metadata. But the bitcode writer
4459   // requires that the module is materialized, so we can cast to non-const here,
4460   // after checking that it is in fact materialized.
4461   assert(M.isMaterialized());
4462   Mods.push_back(const_cast<Module *>(&M));
4463 
4464   ThinLinkBitcodeWriter ThinLinkWriter(M, StrtabBuilder, *Stream, Index,
4465                                        ModHash);
4466   ThinLinkWriter.write();
4467 }
4468 
4469 // Write the specified thin link bitcode file to the given raw output stream,
4470 // where it will be written in a new bitcode block. This is used when
4471 // writing the per-module index file for ThinLTO.
4472 void llvm::WriteThinLinkBitcodeToFile(const Module &M, raw_ostream &Out,
4473                                       const ModuleSummaryIndex &Index,
4474                                       const ModuleHash &ModHash) {
4475   SmallVector<char, 0> Buffer;
4476   Buffer.reserve(256 * 1024);
4477 
4478   BitcodeWriter Writer(Buffer);
4479   Writer.writeThinLinkBitcode(M, Index, ModHash);
4480   Writer.writeSymtab();
4481   Writer.writeStrtab();
4482 
4483   Out.write((char *)&Buffer.front(), Buffer.size());
4484 }
4485