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