xref: /llvm-project/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp (revision 176c3efa0ec876b748fe5c44ad431b1fec97537b)
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/IR/Attributes.h"
32 #include "llvm/IR/BasicBlock.h"
33 #include "llvm/IR/CallSite.h"
34 #include "llvm/IR/Comdat.h"
35 #include "llvm/IR/Constant.h"
36 #include "llvm/IR/Constants.h"
37 #include "llvm/IR/DebugInfoMetadata.h"
38 #include "llvm/IR/DebugLoc.h"
39 #include "llvm/IR/DerivedTypes.h"
40 #include "llvm/IR/Function.h"
41 #include "llvm/IR/GlobalAlias.h"
42 #include "llvm/IR/GlobalIFunc.h"
43 #include "llvm/IR/GlobalObject.h"
44 #include "llvm/IR/GlobalValue.h"
45 #include "llvm/IR/GlobalVariable.h"
46 #include "llvm/IR/InlineAsm.h"
47 #include "llvm/IR/InstrTypes.h"
48 #include "llvm/IR/Instruction.h"
49 #include "llvm/IR/Instructions.h"
50 #include "llvm/IR/LLVMContext.h"
51 #include "llvm/IR/Metadata.h"
52 #include "llvm/IR/Module.h"
53 #include "llvm/IR/ModuleSummaryIndex.h"
54 #include "llvm/IR/Operator.h"
55 #include "llvm/IR/Type.h"
56 #include "llvm/IR/UseListOrder.h"
57 #include "llvm/IR/Value.h"
58 #include "llvm/IR/ValueSymbolTable.h"
59 #include "llvm/MC/StringTableBuilder.h"
60 #include "llvm/Object/IRSymtab.h"
61 #include "llvm/Support/AtomicOrdering.h"
62 #include "llvm/Support/Casting.h"
63 #include "llvm/Support/CommandLine.h"
64 #include "llvm/Support/Endian.h"
65 #include "llvm/Support/Error.h"
66 #include "llvm/Support/ErrorHandling.h"
67 #include "llvm/Support/MathExtras.h"
68 #include "llvm/Support/SHA1.h"
69 #include "llvm/Support/TargetRegistry.h"
70 #include "llvm/Support/raw_ostream.h"
71 #include <algorithm>
72 #include <cassert>
73 #include <cstddef>
74 #include <cstdint>
75 #include <iterator>
76 #include <map>
77 #include <memory>
78 #include <string>
79 #include <utility>
80 #include <vector>
81 
82 using namespace llvm;
83 
84 static cl::opt<unsigned>
85     IndexThreshold("bitcode-mdindex-threshold", cl::Hidden, cl::init(25),
86                    cl::desc("Number of metadatas above which we emit an index "
87                             "to enable lazy-loading"));
88 
89 cl::opt<bool> WriteRelBFToSummary(
90     "write-relbf-to-summary", cl::Hidden, cl::init(false),
91     cl::desc("Write relative block frequency to function summary "));
92 
93 extern FunctionSummary::ForceSummaryHotnessType ForceSummaryEdgesCold;
94 
95 namespace {
96 
97 /// These are manifest constants used by the bitcode writer. They do not need to
98 /// be kept in sync with the reader, but need to be consistent within this file.
99 enum {
100   // VALUE_SYMTAB_BLOCK abbrev id's.
101   VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
102   VST_ENTRY_7_ABBREV,
103   VST_ENTRY_6_ABBREV,
104   VST_BBENTRY_6_ABBREV,
105 
106   // CONSTANTS_BLOCK abbrev id's.
107   CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
108   CONSTANTS_INTEGER_ABBREV,
109   CONSTANTS_CE_CAST_Abbrev,
110   CONSTANTS_NULL_Abbrev,
111 
112   // FUNCTION_BLOCK abbrev id's.
113   FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
114   FUNCTION_INST_BINOP_ABBREV,
115   FUNCTION_INST_BINOP_FLAGS_ABBREV,
116   FUNCTION_INST_CAST_ABBREV,
117   FUNCTION_INST_RET_VOID_ABBREV,
118   FUNCTION_INST_RET_VAL_ABBREV,
119   FUNCTION_INST_UNREACHABLE_ABBREV,
120   FUNCTION_INST_GEP_ABBREV,
121 };
122 
123 /// Abstract class to manage the bitcode writing, subclassed for each bitcode
124 /// file type.
125 class BitcodeWriterBase {
126 protected:
127   /// The stream created and owned by the client.
128   BitstreamWriter &Stream;
129 
130   StringTableBuilder &StrtabBuilder;
131 
132 public:
133   /// Constructs a BitcodeWriterBase object that writes to the provided
134   /// \p Stream.
135   BitcodeWriterBase(BitstreamWriter &Stream, StringTableBuilder &StrtabBuilder)
136       : Stream(Stream), StrtabBuilder(StrtabBuilder) {}
137 
138 protected:
139   void writeBitcodeHeader();
140   void writeModuleVersion();
141 };
142 
143 void BitcodeWriterBase::writeModuleVersion() {
144   // VERSION: [version#]
145   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, ArrayRef<uint64_t>{2});
146 }
147 
148 /// Base class to manage the module bitcode writing, currently subclassed for
149 /// ModuleBitcodeWriter and ThinLinkBitcodeWriter.
150 class ModuleBitcodeWriterBase : public BitcodeWriterBase {
151 protected:
152   /// The Module to write to bitcode.
153   const Module &M;
154 
155   /// Enumerates ids for all values in the module.
156   ValueEnumerator VE;
157 
158   /// Optional per-module index to write for ThinLTO.
159   const ModuleSummaryIndex *Index;
160 
161   /// Map that holds the correspondence between GUIDs in the summary index,
162   /// that came from indirect call profiles, and a value id generated by this
163   /// class to use in the VST and summary block records.
164   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
165 
166   /// Tracks the last value id recorded in the GUIDToValueMap.
167   unsigned GlobalValueId;
168 
169   /// Saves the offset of the VSTOffset record that must eventually be
170   /// backpatched with the offset of the actual VST.
171   uint64_t VSTOffsetPlaceholder = 0;
172 
173 public:
174   /// Constructs a ModuleBitcodeWriterBase object for the given Module,
175   /// writing to the provided \p Buffer.
176   ModuleBitcodeWriterBase(const Module &M, StringTableBuilder &StrtabBuilder,
177                           BitstreamWriter &Stream,
178                           bool ShouldPreserveUseListOrder,
179                           const ModuleSummaryIndex *Index)
180       : BitcodeWriterBase(Stream, StrtabBuilder), M(M),
181         VE(M, ShouldPreserveUseListOrder), Index(Index) {
182     // Assign ValueIds to any callee values in the index that came from
183     // indirect call profiles and were recorded as a GUID not a Value*
184     // (which would have been assigned an ID by the ValueEnumerator).
185     // The starting ValueId is just after the number of values in the
186     // ValueEnumerator, so that they can be emitted in the VST.
187     GlobalValueId = VE.getValues().size();
188     if (!Index)
189       return;
190     for (const auto &GUIDSummaryLists : *Index)
191       // Examine all summaries for this GUID.
192       for (auto &Summary : GUIDSummaryLists.second.SummaryList)
193         if (auto FS = dyn_cast<FunctionSummary>(Summary.get()))
194           // For each call in the function summary, see if the call
195           // is to a GUID (which means it is for an indirect call,
196           // otherwise we would have a Value for it). If so, synthesize
197           // a value id.
198           for (auto &CallEdge : FS->calls())
199             if (!CallEdge.first.getValue())
200               assignValueId(CallEdge.first.getGUID());
201   }
202 
203 protected:
204   void writePerModuleGlobalValueSummary();
205 
206 private:
207   void writePerModuleFunctionSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
208                                            GlobalValueSummary *Summary,
209                                            unsigned ValueID,
210                                            unsigned FSCallsAbbrev,
211                                            unsigned FSCallsProfileAbbrev,
212                                            const Function &F);
213   void writeModuleLevelReferences(const GlobalVariable &V,
214                                   SmallVector<uint64_t, 64> &NameVals,
215                                   unsigned FSModRefsAbbrev);
216 
217   void assignValueId(GlobalValue::GUID ValGUID) {
218     GUIDToValueIdMap[ValGUID] = ++GlobalValueId;
219   }
220 
221   unsigned getValueId(GlobalValue::GUID ValGUID) {
222     const auto &VMI = GUIDToValueIdMap.find(ValGUID);
223     // Expect that any GUID value had a value Id assigned by an
224     // earlier call to assignValueId.
225     assert(VMI != GUIDToValueIdMap.end() &&
226            "GUID does not have assigned value Id");
227     return VMI->second;
228   }
229 
230   // Helper to get the valueId for the type of value recorded in VI.
231   unsigned getValueId(ValueInfo VI) {
232     if (!VI.getValue())
233       return getValueId(VI.getGUID());
234     return VE.getValueID(VI.getValue());
235   }
236 
237   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
238 };
239 
240 /// Class to manage the bitcode writing for a module.
241 class ModuleBitcodeWriter : public ModuleBitcodeWriterBase {
242   /// Pointer to the buffer allocated by caller for bitcode writing.
243   const SmallVectorImpl<char> &Buffer;
244 
245   /// True if a module hash record should be written.
246   bool GenerateHash;
247 
248   /// If non-null, when GenerateHash is true, the resulting hash is written
249   /// into ModHash.
250   ModuleHash *ModHash;
251 
252   SHA1 Hasher;
253 
254   /// The start bit of the identification block.
255   uint64_t BitcodeStartBit;
256 
257 public:
258   /// Constructs a ModuleBitcodeWriter object for the given Module,
259   /// writing to the provided \p Buffer.
260   ModuleBitcodeWriter(const Module &M, SmallVectorImpl<char> &Buffer,
261                       StringTableBuilder &StrtabBuilder,
262                       BitstreamWriter &Stream, bool ShouldPreserveUseListOrder,
263                       const ModuleSummaryIndex *Index, bool GenerateHash,
264                       ModuleHash *ModHash = nullptr)
265       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
266                                 ShouldPreserveUseListOrder, Index),
267         Buffer(Buffer), GenerateHash(GenerateHash), ModHash(ModHash),
268         BitcodeStartBit(Stream.GetCurrentBitNo()) {}
269 
270   /// Emit the current module to the bitstream.
271   void write();
272 
273 private:
274   uint64_t bitcodeStartBit() { return BitcodeStartBit; }
275 
276   size_t addToStrtab(StringRef Str);
277 
278   void writeAttributeGroupTable();
279   void writeAttributeTable();
280   void writeTypeTable();
281   void writeComdats();
282   void writeValueSymbolTableForwardDecl();
283   void writeModuleInfo();
284   void writeValueAsMetadata(const ValueAsMetadata *MD,
285                             SmallVectorImpl<uint64_t> &Record);
286   void writeMDTuple(const MDTuple *N, SmallVectorImpl<uint64_t> &Record,
287                     unsigned Abbrev);
288   unsigned createDILocationAbbrev();
289   void writeDILocation(const DILocation *N, SmallVectorImpl<uint64_t> &Record,
290                        unsigned &Abbrev);
291   unsigned createGenericDINodeAbbrev();
292   void writeGenericDINode(const GenericDINode *N,
293                           SmallVectorImpl<uint64_t> &Record, unsigned &Abbrev);
294   void writeDISubrange(const DISubrange *N, SmallVectorImpl<uint64_t> &Record,
295                        unsigned Abbrev);
296   void writeDIEnumerator(const DIEnumerator *N,
297                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
298   void writeDIBasicType(const DIBasicType *N, SmallVectorImpl<uint64_t> &Record,
299                         unsigned Abbrev);
300   void writeDIDerivedType(const DIDerivedType *N,
301                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
302   void writeDICompositeType(const DICompositeType *N,
303                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
304   void writeDISubroutineType(const DISubroutineType *N,
305                              SmallVectorImpl<uint64_t> &Record,
306                              unsigned Abbrev);
307   void writeDIFile(const DIFile *N, SmallVectorImpl<uint64_t> &Record,
308                    unsigned Abbrev);
309   void writeDICompileUnit(const DICompileUnit *N,
310                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
311   void writeDISubprogram(const DISubprogram *N,
312                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
313   void writeDILexicalBlock(const DILexicalBlock *N,
314                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
315   void writeDILexicalBlockFile(const DILexicalBlockFile *N,
316                                SmallVectorImpl<uint64_t> &Record,
317                                unsigned Abbrev);
318   void writeDINamespace(const DINamespace *N, SmallVectorImpl<uint64_t> &Record,
319                         unsigned Abbrev);
320   void writeDIMacro(const DIMacro *N, SmallVectorImpl<uint64_t> &Record,
321                     unsigned Abbrev);
322   void writeDIMacroFile(const DIMacroFile *N, SmallVectorImpl<uint64_t> &Record,
323                         unsigned Abbrev);
324   void writeDIModule(const DIModule *N, SmallVectorImpl<uint64_t> &Record,
325                      unsigned Abbrev);
326   void writeDITemplateTypeParameter(const DITemplateTypeParameter *N,
327                                     SmallVectorImpl<uint64_t> &Record,
328                                     unsigned Abbrev);
329   void writeDITemplateValueParameter(const DITemplateValueParameter *N,
330                                      SmallVectorImpl<uint64_t> &Record,
331                                      unsigned Abbrev);
332   void writeDIGlobalVariable(const DIGlobalVariable *N,
333                              SmallVectorImpl<uint64_t> &Record,
334                              unsigned Abbrev);
335   void writeDILocalVariable(const DILocalVariable *N,
336                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
337   void writeDIExpression(const DIExpression *N,
338                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
339   void writeDIGlobalVariableExpression(const DIGlobalVariableExpression *N,
340                                        SmallVectorImpl<uint64_t> &Record,
341                                        unsigned Abbrev);
342   void writeDIObjCProperty(const DIObjCProperty *N,
343                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
344   void writeDIImportedEntity(const DIImportedEntity *N,
345                              SmallVectorImpl<uint64_t> &Record,
346                              unsigned Abbrev);
347   unsigned createNamedMetadataAbbrev();
348   void writeNamedMetadata(SmallVectorImpl<uint64_t> &Record);
349   unsigned createMetadataStringsAbbrev();
350   void writeMetadataStrings(ArrayRef<const Metadata *> Strings,
351                             SmallVectorImpl<uint64_t> &Record);
352   void writeMetadataRecords(ArrayRef<const Metadata *> MDs,
353                             SmallVectorImpl<uint64_t> &Record,
354                             std::vector<unsigned> *MDAbbrevs = nullptr,
355                             std::vector<uint64_t> *IndexPos = nullptr);
356   void writeModuleMetadata();
357   void writeFunctionMetadata(const Function &F);
358   void writeFunctionMetadataAttachment(const Function &F);
359   void writeGlobalVariableMetadataAttachment(const GlobalVariable &GV);
360   void pushGlobalMetadataAttachment(SmallVectorImpl<uint64_t> &Record,
361                                     const GlobalObject &GO);
362   void writeModuleMetadataKinds();
363   void writeOperandBundleTags();
364   void writeSyncScopeNames();
365   void writeConstants(unsigned FirstVal, unsigned LastVal, bool isGlobal);
366   void writeModuleConstants();
367   bool pushValueAndType(const Value *V, unsigned InstID,
368                         SmallVectorImpl<unsigned> &Vals);
369   void writeOperandBundles(ImmutableCallSite CS, unsigned InstID);
370   void pushValue(const Value *V, unsigned InstID,
371                  SmallVectorImpl<unsigned> &Vals);
372   void pushValueSigned(const Value *V, unsigned InstID,
373                        SmallVectorImpl<uint64_t> &Vals);
374   void writeInstruction(const Instruction &I, unsigned InstID,
375                         SmallVectorImpl<unsigned> &Vals);
376   void writeFunctionLevelValueSymbolTable(const ValueSymbolTable &VST);
377   void writeGlobalValueSymbolTable(
378       DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
379   void writeUseList(UseListOrder &&Order);
380   void writeUseListBlock(const Function *F);
381   void
382   writeFunction(const Function &F,
383                 DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
384   void writeBlockInfo();
385   void writeModuleHash(size_t BlockStartPos);
386 
387   unsigned getEncodedSyncScopeID(SyncScope::ID SSID) {
388     return unsigned(SSID);
389   }
390 };
391 
392 /// Class to manage the bitcode writing for a combined index.
393 class IndexBitcodeWriter : public BitcodeWriterBase {
394   /// The combined index to write to bitcode.
395   const ModuleSummaryIndex &Index;
396 
397   /// When writing a subset of the index for distributed backends, client
398   /// provides a map of modules to the corresponding GUIDs/summaries to write.
399   const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex;
400 
401   /// Map that holds the correspondence between the GUID used in the combined
402   /// index and a value id generated by this class to use in references.
403   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
404 
405   /// Tracks the last value id recorded in the GUIDToValueMap.
406   unsigned GlobalValueId = 0;
407 
408 public:
409   /// Constructs a IndexBitcodeWriter object for the given combined index,
410   /// writing to the provided \p Buffer. When writing a subset of the index
411   /// for a distributed backend, provide a \p ModuleToSummariesForIndex map.
412   IndexBitcodeWriter(BitstreamWriter &Stream, StringTableBuilder &StrtabBuilder,
413                      const ModuleSummaryIndex &Index,
414                      const std::map<std::string, GVSummaryMapTy>
415                          *ModuleToSummariesForIndex = nullptr)
416       : BitcodeWriterBase(Stream, StrtabBuilder), Index(Index),
417         ModuleToSummariesForIndex(ModuleToSummariesForIndex) {
418     // Assign unique value ids to all summaries to be written, for use
419     // in writing out the call graph edges. Save the mapping from GUID
420     // to the new global value id to use when writing those edges, which
421     // are currently saved in the index in terms of GUID.
422     forEachSummary([&](GVInfo I, bool) {
423       GUIDToValueIdMap[I.first] = ++GlobalValueId;
424     });
425   }
426 
427   /// The below iterator returns the GUID and associated summary.
428   using GVInfo = std::pair<GlobalValue::GUID, GlobalValueSummary *>;
429 
430   /// Calls the callback for each value GUID and summary to be written to
431   /// bitcode. This hides the details of whether they are being pulled from the
432   /// entire index or just those in a provided ModuleToSummariesForIndex map.
433   template<typename Functor>
434   void forEachSummary(Functor Callback) {
435     if (ModuleToSummariesForIndex) {
436       for (auto &M : *ModuleToSummariesForIndex)
437         for (auto &Summary : M.second) {
438           Callback(Summary, false);
439           // Ensure aliasee is handled, e.g. for assigning a valueId,
440           // even if we are not importing the aliasee directly (the
441           // imported alias will contain a copy of aliasee).
442           if (auto *AS = dyn_cast<AliasSummary>(Summary.getSecond()))
443             Callback({AS->getAliaseeGUID(), &AS->getAliasee()}, true);
444         }
445     } else {
446       for (auto &Summaries : Index)
447         for (auto &Summary : Summaries.second.SummaryList)
448           Callback({Summaries.first, Summary.get()}, false);
449     }
450   }
451 
452   /// Calls the callback for each entry in the modulePaths StringMap that
453   /// should be written to the module path string table. This hides the details
454   /// of whether they are being pulled from the entire index or just those in a
455   /// provided ModuleToSummariesForIndex map.
456   template <typename Functor> void forEachModule(Functor Callback) {
457     if (ModuleToSummariesForIndex) {
458       for (const auto &M : *ModuleToSummariesForIndex) {
459         const auto &MPI = Index.modulePaths().find(M.first);
460         if (MPI == Index.modulePaths().end()) {
461           // This should only happen if the bitcode file was empty, in which
462           // case we shouldn't be importing (the ModuleToSummariesForIndex
463           // would only include the module we are writing and index for).
464           assert(ModuleToSummariesForIndex->size() == 1);
465           continue;
466         }
467         Callback(*MPI);
468       }
469     } else {
470       for (const auto &MPSE : Index.modulePaths())
471         Callback(MPSE);
472     }
473   }
474 
475   /// Main entry point for writing a combined index to bitcode.
476   void write();
477 
478 private:
479   void writeModStrings();
480   void writeCombinedGlobalValueSummary();
481 
482   Optional<unsigned> getValueId(GlobalValue::GUID ValGUID) {
483     auto VMI = GUIDToValueIdMap.find(ValGUID);
484     if (VMI == GUIDToValueIdMap.end())
485       return None;
486     return VMI->second;
487   }
488 
489   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
490 };
491 
492 } // end anonymous namespace
493 
494 static unsigned getEncodedCastOpcode(unsigned Opcode) {
495   switch (Opcode) {
496   default: llvm_unreachable("Unknown cast instruction!");
497   case Instruction::Trunc   : return bitc::CAST_TRUNC;
498   case Instruction::ZExt    : return bitc::CAST_ZEXT;
499   case Instruction::SExt    : return bitc::CAST_SEXT;
500   case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
501   case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
502   case Instruction::UIToFP  : return bitc::CAST_UITOFP;
503   case Instruction::SIToFP  : return bitc::CAST_SITOFP;
504   case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
505   case Instruction::FPExt   : return bitc::CAST_FPEXT;
506   case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
507   case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
508   case Instruction::BitCast : return bitc::CAST_BITCAST;
509   case Instruction::AddrSpaceCast: return bitc::CAST_ADDRSPACECAST;
510   }
511 }
512 
513 static unsigned getEncodedBinaryOpcode(unsigned Opcode) {
514   switch (Opcode) {
515   default: llvm_unreachable("Unknown binary instruction!");
516   case Instruction::Add:
517   case Instruction::FAdd: return bitc::BINOP_ADD;
518   case Instruction::Sub:
519   case Instruction::FSub: return bitc::BINOP_SUB;
520   case Instruction::Mul:
521   case Instruction::FMul: return bitc::BINOP_MUL;
522   case Instruction::UDiv: return bitc::BINOP_UDIV;
523   case Instruction::FDiv:
524   case Instruction::SDiv: return bitc::BINOP_SDIV;
525   case Instruction::URem: return bitc::BINOP_UREM;
526   case Instruction::FRem:
527   case Instruction::SRem: return bitc::BINOP_SREM;
528   case Instruction::Shl:  return bitc::BINOP_SHL;
529   case Instruction::LShr: return bitc::BINOP_LSHR;
530   case Instruction::AShr: return bitc::BINOP_ASHR;
531   case Instruction::And:  return bitc::BINOP_AND;
532   case Instruction::Or:   return bitc::BINOP_OR;
533   case Instruction::Xor:  return bitc::BINOP_XOR;
534   }
535 }
536 
537 static unsigned getEncodedRMWOperation(AtomicRMWInst::BinOp Op) {
538   switch (Op) {
539   default: llvm_unreachable("Unknown RMW operation!");
540   case AtomicRMWInst::Xchg: return bitc::RMW_XCHG;
541   case AtomicRMWInst::Add: return bitc::RMW_ADD;
542   case AtomicRMWInst::Sub: return bitc::RMW_SUB;
543   case AtomicRMWInst::And: return bitc::RMW_AND;
544   case AtomicRMWInst::Nand: return bitc::RMW_NAND;
545   case AtomicRMWInst::Or: return bitc::RMW_OR;
546   case AtomicRMWInst::Xor: return bitc::RMW_XOR;
547   case AtomicRMWInst::Max: return bitc::RMW_MAX;
548   case AtomicRMWInst::Min: return bitc::RMW_MIN;
549   case AtomicRMWInst::UMax: return bitc::RMW_UMAX;
550   case AtomicRMWInst::UMin: return bitc::RMW_UMIN;
551   }
552 }
553 
554 static unsigned getEncodedOrdering(AtomicOrdering Ordering) {
555   switch (Ordering) {
556   case AtomicOrdering::NotAtomic: return bitc::ORDERING_NOTATOMIC;
557   case AtomicOrdering::Unordered: return bitc::ORDERING_UNORDERED;
558   case AtomicOrdering::Monotonic: return bitc::ORDERING_MONOTONIC;
559   case AtomicOrdering::Acquire: return bitc::ORDERING_ACQUIRE;
560   case AtomicOrdering::Release: return bitc::ORDERING_RELEASE;
561   case AtomicOrdering::AcquireRelease: return bitc::ORDERING_ACQREL;
562   case AtomicOrdering::SequentiallyConsistent: return bitc::ORDERING_SEQCST;
563   }
564   llvm_unreachable("Invalid ordering");
565 }
566 
567 static void writeStringRecord(BitstreamWriter &Stream, unsigned Code,
568                               StringRef Str, unsigned AbbrevToUse) {
569   SmallVector<unsigned, 64> Vals;
570 
571   // Code: [strchar x N]
572   for (unsigned i = 0, e = Str.size(); i != e; ++i) {
573     if (AbbrevToUse && !BitCodeAbbrevOp::isChar6(Str[i]))
574       AbbrevToUse = 0;
575     Vals.push_back(Str[i]);
576   }
577 
578   // Emit the finished record.
579   Stream.EmitRecord(Code, Vals, AbbrevToUse);
580 }
581 
582 static uint64_t getAttrKindEncoding(Attribute::AttrKind Kind) {
583   switch (Kind) {
584   case Attribute::Alignment:
585     return bitc::ATTR_KIND_ALIGNMENT;
586   case Attribute::AllocSize:
587     return bitc::ATTR_KIND_ALLOC_SIZE;
588   case Attribute::AlwaysInline:
589     return bitc::ATTR_KIND_ALWAYS_INLINE;
590   case Attribute::ArgMemOnly:
591     return bitc::ATTR_KIND_ARGMEMONLY;
592   case Attribute::Builtin:
593     return bitc::ATTR_KIND_BUILTIN;
594   case Attribute::ByVal:
595     return bitc::ATTR_KIND_BY_VAL;
596   case Attribute::Convergent:
597     return bitc::ATTR_KIND_CONVERGENT;
598   case Attribute::InAlloca:
599     return bitc::ATTR_KIND_IN_ALLOCA;
600   case Attribute::Cold:
601     return bitc::ATTR_KIND_COLD;
602   case Attribute::InaccessibleMemOnly:
603     return bitc::ATTR_KIND_INACCESSIBLEMEM_ONLY;
604   case Attribute::InaccessibleMemOrArgMemOnly:
605     return bitc::ATTR_KIND_INACCESSIBLEMEM_OR_ARGMEMONLY;
606   case Attribute::InlineHint:
607     return bitc::ATTR_KIND_INLINE_HINT;
608   case Attribute::InReg:
609     return bitc::ATTR_KIND_IN_REG;
610   case Attribute::JumpTable:
611     return bitc::ATTR_KIND_JUMP_TABLE;
612   case Attribute::MinSize:
613     return bitc::ATTR_KIND_MIN_SIZE;
614   case Attribute::Naked:
615     return bitc::ATTR_KIND_NAKED;
616   case Attribute::Nest:
617     return bitc::ATTR_KIND_NEST;
618   case Attribute::NoAlias:
619     return bitc::ATTR_KIND_NO_ALIAS;
620   case Attribute::NoBuiltin:
621     return bitc::ATTR_KIND_NO_BUILTIN;
622   case Attribute::NoCapture:
623     return bitc::ATTR_KIND_NO_CAPTURE;
624   case Attribute::NoDuplicate:
625     return bitc::ATTR_KIND_NO_DUPLICATE;
626   case Attribute::NoImplicitFloat:
627     return bitc::ATTR_KIND_NO_IMPLICIT_FLOAT;
628   case Attribute::NoInline:
629     return bitc::ATTR_KIND_NO_INLINE;
630   case Attribute::NoRecurse:
631     return bitc::ATTR_KIND_NO_RECURSE;
632   case Attribute::NonLazyBind:
633     return bitc::ATTR_KIND_NON_LAZY_BIND;
634   case Attribute::NonNull:
635     return bitc::ATTR_KIND_NON_NULL;
636   case Attribute::Dereferenceable:
637     return bitc::ATTR_KIND_DEREFERENCEABLE;
638   case Attribute::DereferenceableOrNull:
639     return bitc::ATTR_KIND_DEREFERENCEABLE_OR_NULL;
640   case Attribute::NoRedZone:
641     return bitc::ATTR_KIND_NO_RED_ZONE;
642   case Attribute::NoReturn:
643     return bitc::ATTR_KIND_NO_RETURN;
644   case Attribute::NoCfCheck:
645     return bitc::ATTR_KIND_NOCF_CHECK;
646   case Attribute::NoUnwind:
647     return bitc::ATTR_KIND_NO_UNWIND;
648   case Attribute::OptForFuzzing:
649     return bitc::ATTR_KIND_OPT_FOR_FUZZING;
650   case Attribute::OptimizeForSize:
651     return bitc::ATTR_KIND_OPTIMIZE_FOR_SIZE;
652   case Attribute::OptimizeNone:
653     return bitc::ATTR_KIND_OPTIMIZE_NONE;
654   case Attribute::ReadNone:
655     return bitc::ATTR_KIND_READ_NONE;
656   case Attribute::ReadOnly:
657     return bitc::ATTR_KIND_READ_ONLY;
658   case Attribute::Returned:
659     return bitc::ATTR_KIND_RETURNED;
660   case Attribute::ReturnsTwice:
661     return bitc::ATTR_KIND_RETURNS_TWICE;
662   case Attribute::SExt:
663     return bitc::ATTR_KIND_S_EXT;
664   case Attribute::Speculatable:
665     return bitc::ATTR_KIND_SPECULATABLE;
666   case Attribute::StackAlignment:
667     return bitc::ATTR_KIND_STACK_ALIGNMENT;
668   case Attribute::StackProtect:
669     return bitc::ATTR_KIND_STACK_PROTECT;
670   case Attribute::StackProtectReq:
671     return bitc::ATTR_KIND_STACK_PROTECT_REQ;
672   case Attribute::StackProtectStrong:
673     return bitc::ATTR_KIND_STACK_PROTECT_STRONG;
674   case Attribute::SafeStack:
675     return bitc::ATTR_KIND_SAFESTACK;
676   case Attribute::ShadowCallStack:
677     return bitc::ATTR_KIND_SHADOWCALLSTACK;
678   case Attribute::StrictFP:
679     return bitc::ATTR_KIND_STRICT_FP;
680   case Attribute::StructRet:
681     return bitc::ATTR_KIND_STRUCT_RET;
682   case Attribute::SanitizeAddress:
683     return bitc::ATTR_KIND_SANITIZE_ADDRESS;
684   case Attribute::SanitizeHWAddress:
685     return bitc::ATTR_KIND_SANITIZE_HWADDRESS;
686   case Attribute::SanitizeThread:
687     return bitc::ATTR_KIND_SANITIZE_THREAD;
688   case Attribute::SanitizeMemory:
689     return bitc::ATTR_KIND_SANITIZE_MEMORY;
690   case Attribute::SwiftError:
691     return bitc::ATTR_KIND_SWIFT_ERROR;
692   case Attribute::SwiftSelf:
693     return bitc::ATTR_KIND_SWIFT_SELF;
694   case Attribute::UWTable:
695     return bitc::ATTR_KIND_UW_TABLE;
696   case Attribute::WriteOnly:
697     return bitc::ATTR_KIND_WRITEONLY;
698   case Attribute::ZExt:
699     return bitc::ATTR_KIND_Z_EXT;
700   case Attribute::EndAttrKinds:
701     llvm_unreachable("Can not encode end-attribute kinds marker.");
702   case Attribute::None:
703     llvm_unreachable("Can not encode none-attribute.");
704   }
705 
706   llvm_unreachable("Trying to encode unknown attribute");
707 }
708 
709 void ModuleBitcodeWriter::writeAttributeGroupTable() {
710   const std::vector<ValueEnumerator::IndexAndAttrSet> &AttrGrps =
711       VE.getAttributeGroups();
712   if (AttrGrps.empty()) return;
713 
714   Stream.EnterSubblock(bitc::PARAMATTR_GROUP_BLOCK_ID, 3);
715 
716   SmallVector<uint64_t, 64> Record;
717   for (ValueEnumerator::IndexAndAttrSet Pair : AttrGrps) {
718     unsigned AttrListIndex = Pair.first;
719     AttributeSet AS = Pair.second;
720     Record.push_back(VE.getAttributeGroupID(Pair));
721     Record.push_back(AttrListIndex);
722 
723     for (Attribute Attr : AS) {
724       if (Attr.isEnumAttribute()) {
725         Record.push_back(0);
726         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
727       } else if (Attr.isIntAttribute()) {
728         Record.push_back(1);
729         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
730         Record.push_back(Attr.getValueAsInt());
731       } else {
732         StringRef Kind = Attr.getKindAsString();
733         StringRef Val = Attr.getValueAsString();
734 
735         Record.push_back(Val.empty() ? 3 : 4);
736         Record.append(Kind.begin(), Kind.end());
737         Record.push_back(0);
738         if (!Val.empty()) {
739           Record.append(Val.begin(), Val.end());
740           Record.push_back(0);
741         }
742       }
743     }
744 
745     Stream.EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
746     Record.clear();
747   }
748 
749   Stream.ExitBlock();
750 }
751 
752 void ModuleBitcodeWriter::writeAttributeTable() {
753   const std::vector<AttributeList> &Attrs = VE.getAttributeLists();
754   if (Attrs.empty()) return;
755 
756   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
757 
758   SmallVector<uint64_t, 64> Record;
759   for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
760     AttributeList AL = Attrs[i];
761     for (unsigned i = AL.index_begin(), e = AL.index_end(); i != e; ++i) {
762       AttributeSet AS = AL.getAttributes(i);
763       if (AS.hasAttributes())
764         Record.push_back(VE.getAttributeGroupID({i, AS}));
765     }
766 
767     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
768     Record.clear();
769   }
770 
771   Stream.ExitBlock();
772 }
773 
774 /// WriteTypeTable - Write out the type table for a module.
775 void ModuleBitcodeWriter::writeTypeTable() {
776   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
777 
778   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
779   SmallVector<uint64_t, 64> TypeVals;
780 
781   uint64_t NumBits = VE.computeBitsRequiredForTypeIndicies();
782 
783   // Abbrev for TYPE_CODE_POINTER.
784   auto Abbv = std::make_shared<BitCodeAbbrev>();
785   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
786   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
787   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
788   unsigned PtrAbbrev = Stream.EmitAbbrev(std::move(Abbv));
789 
790   // Abbrev for TYPE_CODE_FUNCTION.
791   Abbv = std::make_shared<BitCodeAbbrev>();
792   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
793   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
794   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
795   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
796   unsigned FunctionAbbrev = Stream.EmitAbbrev(std::move(Abbv));
797 
798   // Abbrev for TYPE_CODE_STRUCT_ANON.
799   Abbv = std::make_shared<BitCodeAbbrev>();
800   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
801   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
802   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
803   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
804   unsigned StructAnonAbbrev = Stream.EmitAbbrev(std::move(Abbv));
805 
806   // Abbrev for TYPE_CODE_STRUCT_NAME.
807   Abbv = std::make_shared<BitCodeAbbrev>();
808   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
809   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
810   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
811   unsigned StructNameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
812 
813   // Abbrev for TYPE_CODE_STRUCT_NAMED.
814   Abbv = std::make_shared<BitCodeAbbrev>();
815   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
816   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
817   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
818   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
819   unsigned StructNamedAbbrev = Stream.EmitAbbrev(std::move(Abbv));
820 
821   // Abbrev for TYPE_CODE_ARRAY.
822   Abbv = std::make_shared<BitCodeAbbrev>();
823   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
824   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
825   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
826   unsigned ArrayAbbrev = Stream.EmitAbbrev(std::move(Abbv));
827 
828   // Emit an entry count so the reader can reserve space.
829   TypeVals.push_back(TypeList.size());
830   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
831   TypeVals.clear();
832 
833   // Loop over all of the types, emitting each in turn.
834   for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
835     Type *T = TypeList[i];
836     int AbbrevToUse = 0;
837     unsigned Code = 0;
838 
839     switch (T->getTypeID()) {
840     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;      break;
841     case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;      break;
842     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;     break;
843     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE;    break;
844     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80;  break;
845     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128;     break;
846     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
847     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;     break;
848     case Type::MetadataTyID:  Code = bitc::TYPE_CODE_METADATA;  break;
849     case Type::X86_MMXTyID:   Code = bitc::TYPE_CODE_X86_MMX;   break;
850     case Type::TokenTyID:     Code = bitc::TYPE_CODE_TOKEN;     break;
851     case Type::IntegerTyID:
852       // INTEGER: [width]
853       Code = bitc::TYPE_CODE_INTEGER;
854       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
855       break;
856     case Type::PointerTyID: {
857       PointerType *PTy = cast<PointerType>(T);
858       // POINTER: [pointee type, address space]
859       Code = bitc::TYPE_CODE_POINTER;
860       TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
861       unsigned AddressSpace = PTy->getAddressSpace();
862       TypeVals.push_back(AddressSpace);
863       if (AddressSpace == 0) AbbrevToUse = PtrAbbrev;
864       break;
865     }
866     case Type::FunctionTyID: {
867       FunctionType *FT = cast<FunctionType>(T);
868       // FUNCTION: [isvararg, retty, paramty x N]
869       Code = bitc::TYPE_CODE_FUNCTION;
870       TypeVals.push_back(FT->isVarArg());
871       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
872       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
873         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
874       AbbrevToUse = FunctionAbbrev;
875       break;
876     }
877     case Type::StructTyID: {
878       StructType *ST = cast<StructType>(T);
879       // STRUCT: [ispacked, eltty x N]
880       TypeVals.push_back(ST->isPacked());
881       // Output all of the element types.
882       for (StructType::element_iterator I = ST->element_begin(),
883            E = ST->element_end(); I != E; ++I)
884         TypeVals.push_back(VE.getTypeID(*I));
885 
886       if (ST->isLiteral()) {
887         Code = bitc::TYPE_CODE_STRUCT_ANON;
888         AbbrevToUse = StructAnonAbbrev;
889       } else {
890         if (ST->isOpaque()) {
891           Code = bitc::TYPE_CODE_OPAQUE;
892         } else {
893           Code = bitc::TYPE_CODE_STRUCT_NAMED;
894           AbbrevToUse = StructNamedAbbrev;
895         }
896 
897         // Emit the name if it is present.
898         if (!ST->getName().empty())
899           writeStringRecord(Stream, bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
900                             StructNameAbbrev);
901       }
902       break;
903     }
904     case Type::ArrayTyID: {
905       ArrayType *AT = cast<ArrayType>(T);
906       // ARRAY: [numelts, eltty]
907       Code = bitc::TYPE_CODE_ARRAY;
908       TypeVals.push_back(AT->getNumElements());
909       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
910       AbbrevToUse = ArrayAbbrev;
911       break;
912     }
913     case Type::VectorTyID: {
914       VectorType *VT = cast<VectorType>(T);
915       // VECTOR [numelts, eltty]
916       Code = bitc::TYPE_CODE_VECTOR;
917       TypeVals.push_back(VT->getNumElements());
918       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
919       break;
920     }
921     }
922 
923     // Emit the finished record.
924     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
925     TypeVals.clear();
926   }
927 
928   Stream.ExitBlock();
929 }
930 
931 static unsigned getEncodedLinkage(const GlobalValue::LinkageTypes Linkage) {
932   switch (Linkage) {
933   case GlobalValue::ExternalLinkage:
934     return 0;
935   case GlobalValue::WeakAnyLinkage:
936     return 16;
937   case GlobalValue::AppendingLinkage:
938     return 2;
939   case GlobalValue::InternalLinkage:
940     return 3;
941   case GlobalValue::LinkOnceAnyLinkage:
942     return 18;
943   case GlobalValue::ExternalWeakLinkage:
944     return 7;
945   case GlobalValue::CommonLinkage:
946     return 8;
947   case GlobalValue::PrivateLinkage:
948     return 9;
949   case GlobalValue::WeakODRLinkage:
950     return 17;
951   case GlobalValue::LinkOnceODRLinkage:
952     return 19;
953   case GlobalValue::AvailableExternallyLinkage:
954     return 12;
955   }
956   llvm_unreachable("Invalid linkage");
957 }
958 
959 static unsigned getEncodedLinkage(const GlobalValue &GV) {
960   return getEncodedLinkage(GV.getLinkage());
961 }
962 
963 static uint64_t getEncodedFFlags(FunctionSummary::FFlags Flags) {
964   uint64_t RawFlags = 0;
965   RawFlags |= Flags.ReadNone;
966   RawFlags |= (Flags.ReadOnly << 1);
967   RawFlags |= (Flags.NoRecurse << 2);
968   RawFlags |= (Flags.ReturnDoesNotAlias << 3);
969   return RawFlags;
970 }
971 
972 // Decode the flags for GlobalValue in the summary
973 static uint64_t getEncodedGVSummaryFlags(GlobalValueSummary::GVFlags Flags) {
974   uint64_t RawFlags = 0;
975 
976   RawFlags |= Flags.NotEligibleToImport; // bool
977   RawFlags |= (Flags.Live << 1);
978   RawFlags |= (Flags.DSOLocal << 2);
979 
980   // Linkage don't need to be remapped at that time for the summary. Any future
981   // change to the getEncodedLinkage() function will need to be taken into
982   // account here as well.
983   RawFlags = (RawFlags << 4) | Flags.Linkage; // 4 bits
984 
985   return RawFlags;
986 }
987 
988 static unsigned getEncodedVisibility(const GlobalValue &GV) {
989   switch (GV.getVisibility()) {
990   case GlobalValue::DefaultVisibility:   return 0;
991   case GlobalValue::HiddenVisibility:    return 1;
992   case GlobalValue::ProtectedVisibility: return 2;
993   }
994   llvm_unreachable("Invalid visibility");
995 }
996 
997 static unsigned getEncodedDLLStorageClass(const GlobalValue &GV) {
998   switch (GV.getDLLStorageClass()) {
999   case GlobalValue::DefaultStorageClass:   return 0;
1000   case GlobalValue::DLLImportStorageClass: return 1;
1001   case GlobalValue::DLLExportStorageClass: return 2;
1002   }
1003   llvm_unreachable("Invalid DLL storage class");
1004 }
1005 
1006 static unsigned getEncodedThreadLocalMode(const GlobalValue &GV) {
1007   switch (GV.getThreadLocalMode()) {
1008     case GlobalVariable::NotThreadLocal:         return 0;
1009     case GlobalVariable::GeneralDynamicTLSModel: return 1;
1010     case GlobalVariable::LocalDynamicTLSModel:   return 2;
1011     case GlobalVariable::InitialExecTLSModel:    return 3;
1012     case GlobalVariable::LocalExecTLSModel:      return 4;
1013   }
1014   llvm_unreachable("Invalid TLS model");
1015 }
1016 
1017 static unsigned getEncodedComdatSelectionKind(const Comdat &C) {
1018   switch (C.getSelectionKind()) {
1019   case Comdat::Any:
1020     return bitc::COMDAT_SELECTION_KIND_ANY;
1021   case Comdat::ExactMatch:
1022     return bitc::COMDAT_SELECTION_KIND_EXACT_MATCH;
1023   case Comdat::Largest:
1024     return bitc::COMDAT_SELECTION_KIND_LARGEST;
1025   case Comdat::NoDuplicates:
1026     return bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES;
1027   case Comdat::SameSize:
1028     return bitc::COMDAT_SELECTION_KIND_SAME_SIZE;
1029   }
1030   llvm_unreachable("Invalid selection kind");
1031 }
1032 
1033 static unsigned getEncodedUnnamedAddr(const GlobalValue &GV) {
1034   switch (GV.getUnnamedAddr()) {
1035   case GlobalValue::UnnamedAddr::None:   return 0;
1036   case GlobalValue::UnnamedAddr::Local:  return 2;
1037   case GlobalValue::UnnamedAddr::Global: return 1;
1038   }
1039   llvm_unreachable("Invalid unnamed_addr");
1040 }
1041 
1042 size_t ModuleBitcodeWriter::addToStrtab(StringRef Str) {
1043   if (GenerateHash)
1044     Hasher.update(Str);
1045   return StrtabBuilder.add(Str);
1046 }
1047 
1048 void ModuleBitcodeWriter::writeComdats() {
1049   SmallVector<unsigned, 64> Vals;
1050   for (const Comdat *C : VE.getComdats()) {
1051     // COMDAT: [strtab offset, strtab size, selection_kind]
1052     Vals.push_back(addToStrtab(C->getName()));
1053     Vals.push_back(C->getName().size());
1054     Vals.push_back(getEncodedComdatSelectionKind(*C));
1055     Stream.EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
1056     Vals.clear();
1057   }
1058 }
1059 
1060 /// Write a record that will eventually hold the word offset of the
1061 /// module-level VST. For now the offset is 0, which will be backpatched
1062 /// after the real VST is written. Saves the bit offset to backpatch.
1063 void ModuleBitcodeWriter::writeValueSymbolTableForwardDecl() {
1064   // Write a placeholder value in for the offset of the real VST,
1065   // which is written after the function blocks so that it can include
1066   // the offset of each function. The placeholder offset will be
1067   // updated when the real VST is written.
1068   auto Abbv = std::make_shared<BitCodeAbbrev>();
1069   Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_VSTOFFSET));
1070   // Blocks are 32-bit aligned, so we can use a 32-bit word offset to
1071   // hold the real VST offset. Must use fixed instead of VBR as we don't
1072   // know how many VBR chunks to reserve ahead of time.
1073   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
1074   unsigned VSTOffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1075 
1076   // Emit the placeholder
1077   uint64_t Vals[] = {bitc::MODULE_CODE_VSTOFFSET, 0};
1078   Stream.EmitRecordWithAbbrev(VSTOffsetAbbrev, Vals);
1079 
1080   // Compute and save the bit offset to the placeholder, which will be
1081   // patched when the real VST is written. We can simply subtract the 32-bit
1082   // fixed size from the current bit number to get the location to backpatch.
1083   VSTOffsetPlaceholder = Stream.GetCurrentBitNo() - 32;
1084 }
1085 
1086 enum StringEncoding { SE_Char6, SE_Fixed7, SE_Fixed8 };
1087 
1088 /// Determine the encoding to use for the given string name and length.
1089 static StringEncoding getStringEncoding(StringRef Str) {
1090   bool isChar6 = true;
1091   for (char C : Str) {
1092     if (isChar6)
1093       isChar6 = BitCodeAbbrevOp::isChar6(C);
1094     if ((unsigned char)C & 128)
1095       // don't bother scanning the rest.
1096       return SE_Fixed8;
1097   }
1098   if (isChar6)
1099     return SE_Char6;
1100   return SE_Fixed7;
1101 }
1102 
1103 /// Emit top-level description of module, including target triple, inline asm,
1104 /// descriptors for global variables, and function prototype info.
1105 /// Returns the bit offset to backpatch with the location of the real VST.
1106 void ModuleBitcodeWriter::writeModuleInfo() {
1107   // Emit various pieces of data attached to a module.
1108   if (!M.getTargetTriple().empty())
1109     writeStringRecord(Stream, bitc::MODULE_CODE_TRIPLE, M.getTargetTriple(),
1110                       0 /*TODO*/);
1111   const std::string &DL = M.getDataLayoutStr();
1112   if (!DL.empty())
1113     writeStringRecord(Stream, bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/);
1114   if (!M.getModuleInlineAsm().empty())
1115     writeStringRecord(Stream, bitc::MODULE_CODE_ASM, M.getModuleInlineAsm(),
1116                       0 /*TODO*/);
1117 
1118   // Emit information about sections and GC, computing how many there are. Also
1119   // compute the maximum alignment value.
1120   std::map<std::string, unsigned> SectionMap;
1121   std::map<std::string, unsigned> GCMap;
1122   unsigned MaxAlignment = 0;
1123   unsigned MaxGlobalType = 0;
1124   for (const GlobalValue &GV : M.globals()) {
1125     MaxAlignment = std::max(MaxAlignment, GV.getAlignment());
1126     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getValueType()));
1127     if (GV.hasSection()) {
1128       // Give section names unique ID's.
1129       unsigned &Entry = SectionMap[GV.getSection()];
1130       if (!Entry) {
1131         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
1132                           0 /*TODO*/);
1133         Entry = SectionMap.size();
1134       }
1135     }
1136   }
1137   for (const Function &F : M) {
1138     MaxAlignment = std::max(MaxAlignment, F.getAlignment());
1139     if (F.hasSection()) {
1140       // Give section names unique ID's.
1141       unsigned &Entry = SectionMap[F.getSection()];
1142       if (!Entry) {
1143         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
1144                           0 /*TODO*/);
1145         Entry = SectionMap.size();
1146       }
1147     }
1148     if (F.hasGC()) {
1149       // Same for GC names.
1150       unsigned &Entry = GCMap[F.getGC()];
1151       if (!Entry) {
1152         writeStringRecord(Stream, bitc::MODULE_CODE_GCNAME, F.getGC(),
1153                           0 /*TODO*/);
1154         Entry = GCMap.size();
1155       }
1156     }
1157   }
1158 
1159   // Emit abbrev for globals, now that we know # sections and max alignment.
1160   unsigned SimpleGVarAbbrev = 0;
1161   if (!M.global_empty()) {
1162     // Add an abbrev for common globals with no visibility or thread localness.
1163     auto Abbv = std::make_shared<BitCodeAbbrev>();
1164     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
1165     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1166     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1167     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1168                               Log2_32_Ceil(MaxGlobalType+1)));
1169     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddrSpace << 2
1170                                                            //| explicitType << 1
1171                                                            //| constant
1172     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Initializer.
1173     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // Linkage.
1174     if (MaxAlignment == 0)                                 // Alignment.
1175       Abbv->Add(BitCodeAbbrevOp(0));
1176     else {
1177       unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
1178       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1179                                Log2_32_Ceil(MaxEncAlignment+1)));
1180     }
1181     if (SectionMap.empty())                                    // Section.
1182       Abbv->Add(BitCodeAbbrevOp(0));
1183     else
1184       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1185                                Log2_32_Ceil(SectionMap.size()+1)));
1186     // Don't bother emitting vis + thread local.
1187     SimpleGVarAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1188   }
1189 
1190   SmallVector<unsigned, 64> Vals;
1191   // Emit the module's source file name.
1192   {
1193     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
1194     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
1195     if (Bits == SE_Char6)
1196       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
1197     else if (Bits == SE_Fixed7)
1198       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
1199 
1200     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
1201     auto Abbv = std::make_shared<BitCodeAbbrev>();
1202     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
1203     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1204     Abbv->Add(AbbrevOpToUse);
1205     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1206 
1207     for (const auto P : M.getSourceFileName())
1208       Vals.push_back((unsigned char)P);
1209 
1210     // Emit the finished record.
1211     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
1212     Vals.clear();
1213   }
1214 
1215   // Emit the global variable information.
1216   for (const GlobalVariable &GV : M.globals()) {
1217     unsigned AbbrevToUse = 0;
1218 
1219     // GLOBALVAR: [strtab offset, strtab size, type, isconst, initid,
1220     //             linkage, alignment, section, visibility, threadlocal,
1221     //             unnamed_addr, externally_initialized, dllstorageclass,
1222     //             comdat, attributes, DSO_Local]
1223     Vals.push_back(addToStrtab(GV.getName()));
1224     Vals.push_back(GV.getName().size());
1225     Vals.push_back(VE.getTypeID(GV.getValueType()));
1226     Vals.push_back(GV.getType()->getAddressSpace() << 2 | 2 | GV.isConstant());
1227     Vals.push_back(GV.isDeclaration() ? 0 :
1228                    (VE.getValueID(GV.getInitializer()) + 1));
1229     Vals.push_back(getEncodedLinkage(GV));
1230     Vals.push_back(Log2_32(GV.getAlignment())+1);
1231     Vals.push_back(GV.hasSection() ? SectionMap[GV.getSection()] : 0);
1232     if (GV.isThreadLocal() ||
1233         GV.getVisibility() != GlobalValue::DefaultVisibility ||
1234         GV.getUnnamedAddr() != GlobalValue::UnnamedAddr::None ||
1235         GV.isExternallyInitialized() ||
1236         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
1237         GV.hasComdat() ||
1238         GV.hasAttributes() ||
1239         GV.isDSOLocal()) {
1240       Vals.push_back(getEncodedVisibility(GV));
1241       Vals.push_back(getEncodedThreadLocalMode(GV));
1242       Vals.push_back(getEncodedUnnamedAddr(GV));
1243       Vals.push_back(GV.isExternallyInitialized());
1244       Vals.push_back(getEncodedDLLStorageClass(GV));
1245       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
1246 
1247       auto AL = GV.getAttributesAsList(AttributeList::FunctionIndex);
1248       Vals.push_back(VE.getAttributeListID(AL));
1249 
1250       Vals.push_back(GV.isDSOLocal());
1251     } else {
1252       AbbrevToUse = SimpleGVarAbbrev;
1253     }
1254 
1255     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
1256     Vals.clear();
1257   }
1258 
1259   // Emit the function proto information.
1260   for (const Function &F : M) {
1261     // FUNCTION:  [strtab offset, strtab size, type, callingconv, isproto,
1262     //             linkage, paramattrs, alignment, section, visibility, gc,
1263     //             unnamed_addr, prologuedata, dllstorageclass, comdat,
1264     //             prefixdata, personalityfn, DSO_Local]
1265     Vals.push_back(addToStrtab(F.getName()));
1266     Vals.push_back(F.getName().size());
1267     Vals.push_back(VE.getTypeID(F.getFunctionType()));
1268     Vals.push_back(F.getCallingConv());
1269     Vals.push_back(F.isDeclaration());
1270     Vals.push_back(getEncodedLinkage(F));
1271     Vals.push_back(VE.getAttributeListID(F.getAttributes()));
1272     Vals.push_back(Log2_32(F.getAlignment())+1);
1273     Vals.push_back(F.hasSection() ? SectionMap[F.getSection()] : 0);
1274     Vals.push_back(getEncodedVisibility(F));
1275     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
1276     Vals.push_back(getEncodedUnnamedAddr(F));
1277     Vals.push_back(F.hasPrologueData() ? (VE.getValueID(F.getPrologueData()) + 1)
1278                                        : 0);
1279     Vals.push_back(getEncodedDLLStorageClass(F));
1280     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
1281     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
1282                                      : 0);
1283     Vals.push_back(
1284         F.hasPersonalityFn() ? (VE.getValueID(F.getPersonalityFn()) + 1) : 0);
1285 
1286     Vals.push_back(F.isDSOLocal());
1287     unsigned AbbrevToUse = 0;
1288     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
1289     Vals.clear();
1290   }
1291 
1292   // Emit the alias information.
1293   for (const GlobalAlias &A : M.aliases()) {
1294     // ALIAS: [strtab offset, strtab size, alias type, aliasee val#, linkage,
1295     //         visibility, dllstorageclass, threadlocal, unnamed_addr,
1296     //         DSO_Local]
1297     Vals.push_back(addToStrtab(A.getName()));
1298     Vals.push_back(A.getName().size());
1299     Vals.push_back(VE.getTypeID(A.getValueType()));
1300     Vals.push_back(A.getType()->getAddressSpace());
1301     Vals.push_back(VE.getValueID(A.getAliasee()));
1302     Vals.push_back(getEncodedLinkage(A));
1303     Vals.push_back(getEncodedVisibility(A));
1304     Vals.push_back(getEncodedDLLStorageClass(A));
1305     Vals.push_back(getEncodedThreadLocalMode(A));
1306     Vals.push_back(getEncodedUnnamedAddr(A));
1307     Vals.push_back(A.isDSOLocal());
1308 
1309     unsigned AbbrevToUse = 0;
1310     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
1311     Vals.clear();
1312   }
1313 
1314   // Emit the ifunc information.
1315   for (const GlobalIFunc &I : M.ifuncs()) {
1316     // IFUNC: [strtab offset, strtab size, ifunc type, address space, resolver
1317     //         val#, linkage, visibility, DSO_Local]
1318     Vals.push_back(addToStrtab(I.getName()));
1319     Vals.push_back(I.getName().size());
1320     Vals.push_back(VE.getTypeID(I.getValueType()));
1321     Vals.push_back(I.getType()->getAddressSpace());
1322     Vals.push_back(VE.getValueID(I.getResolver()));
1323     Vals.push_back(getEncodedLinkage(I));
1324     Vals.push_back(getEncodedVisibility(I));
1325     Vals.push_back(I.isDSOLocal());
1326     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
1327     Vals.clear();
1328   }
1329 
1330   writeValueSymbolTableForwardDecl();
1331 }
1332 
1333 static uint64_t getOptimizationFlags(const Value *V) {
1334   uint64_t Flags = 0;
1335 
1336   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
1337     if (OBO->hasNoSignedWrap())
1338       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
1339     if (OBO->hasNoUnsignedWrap())
1340       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
1341   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
1342     if (PEO->isExact())
1343       Flags |= 1 << bitc::PEO_EXACT;
1344   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
1345     if (FPMO->hasAllowReassoc())
1346       Flags |= bitc::AllowReassoc;
1347     if (FPMO->hasNoNaNs())
1348       Flags |= bitc::NoNaNs;
1349     if (FPMO->hasNoInfs())
1350       Flags |= bitc::NoInfs;
1351     if (FPMO->hasNoSignedZeros())
1352       Flags |= bitc::NoSignedZeros;
1353     if (FPMO->hasAllowReciprocal())
1354       Flags |= bitc::AllowReciprocal;
1355     if (FPMO->hasAllowContract())
1356       Flags |= bitc::AllowContract;
1357     if (FPMO->hasApproxFunc())
1358       Flags |= bitc::ApproxFunc;
1359   }
1360 
1361   return Flags;
1362 }
1363 
1364 void ModuleBitcodeWriter::writeValueAsMetadata(
1365     const ValueAsMetadata *MD, SmallVectorImpl<uint64_t> &Record) {
1366   // Mimic an MDNode with a value as one operand.
1367   Value *V = MD->getValue();
1368   Record.push_back(VE.getTypeID(V->getType()));
1369   Record.push_back(VE.getValueID(V));
1370   Stream.EmitRecord(bitc::METADATA_VALUE, Record, 0);
1371   Record.clear();
1372 }
1373 
1374 void ModuleBitcodeWriter::writeMDTuple(const MDTuple *N,
1375                                        SmallVectorImpl<uint64_t> &Record,
1376                                        unsigned Abbrev) {
1377   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
1378     Metadata *MD = N->getOperand(i);
1379     assert(!(MD && isa<LocalAsMetadata>(MD)) &&
1380            "Unexpected function-local metadata");
1381     Record.push_back(VE.getMetadataOrNullID(MD));
1382   }
1383   Stream.EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
1384                                     : bitc::METADATA_NODE,
1385                     Record, Abbrev);
1386   Record.clear();
1387 }
1388 
1389 unsigned ModuleBitcodeWriter::createDILocationAbbrev() {
1390   // Assume the column is usually under 128, and always output the inlined-at
1391   // location (it's never more expensive than building an array size 1).
1392   auto Abbv = std::make_shared<BitCodeAbbrev>();
1393   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
1394   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1395   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1396   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1397   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1398   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1399   return Stream.EmitAbbrev(std::move(Abbv));
1400 }
1401 
1402 void ModuleBitcodeWriter::writeDILocation(const DILocation *N,
1403                                           SmallVectorImpl<uint64_t> &Record,
1404                                           unsigned &Abbrev) {
1405   if (!Abbrev)
1406     Abbrev = createDILocationAbbrev();
1407 
1408   Record.push_back(N->isDistinct());
1409   Record.push_back(N->getLine());
1410   Record.push_back(N->getColumn());
1411   Record.push_back(VE.getMetadataID(N->getScope()));
1412   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
1413 
1414   Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
1415   Record.clear();
1416 }
1417 
1418 unsigned ModuleBitcodeWriter::createGenericDINodeAbbrev() {
1419   // Assume the column is usually under 128, and always output the inlined-at
1420   // location (it's never more expensive than building an array size 1).
1421   auto Abbv = std::make_shared<BitCodeAbbrev>();
1422   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
1423   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1424   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1425   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1426   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1427   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1428   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1429   return Stream.EmitAbbrev(std::move(Abbv));
1430 }
1431 
1432 void ModuleBitcodeWriter::writeGenericDINode(const GenericDINode *N,
1433                                              SmallVectorImpl<uint64_t> &Record,
1434                                              unsigned &Abbrev) {
1435   if (!Abbrev)
1436     Abbrev = createGenericDINodeAbbrev();
1437 
1438   Record.push_back(N->isDistinct());
1439   Record.push_back(N->getTag());
1440   Record.push_back(0); // Per-tag version field; unused for now.
1441 
1442   for (auto &I : N->operands())
1443     Record.push_back(VE.getMetadataOrNullID(I));
1444 
1445   Stream.EmitRecord(bitc::METADATA_GENERIC_DEBUG, Record, Abbrev);
1446   Record.clear();
1447 }
1448 
1449 static uint64_t rotateSign(int64_t I) {
1450   uint64_t U = I;
1451   return I < 0 ? ~(U << 1) : U << 1;
1452 }
1453 
1454 void ModuleBitcodeWriter::writeDISubrange(const DISubrange *N,
1455                                           SmallVectorImpl<uint64_t> &Record,
1456                                           unsigned Abbrev) {
1457   const uint64_t Version = 1 << 1;
1458   Record.push_back((uint64_t)N->isDistinct() | Version);
1459   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1460   Record.push_back(rotateSign(N->getLowerBound()));
1461 
1462   Stream.EmitRecord(bitc::METADATA_SUBRANGE, Record, Abbrev);
1463   Record.clear();
1464 }
1465 
1466 void ModuleBitcodeWriter::writeDIEnumerator(const DIEnumerator *N,
1467                                             SmallVectorImpl<uint64_t> &Record,
1468                                             unsigned Abbrev) {
1469   Record.push_back((N->isUnsigned() << 1) | N->isDistinct());
1470   Record.push_back(rotateSign(N->getValue()));
1471   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1472 
1473   Stream.EmitRecord(bitc::METADATA_ENUMERATOR, Record, Abbrev);
1474   Record.clear();
1475 }
1476 
1477 void ModuleBitcodeWriter::writeDIBasicType(const DIBasicType *N,
1478                                            SmallVectorImpl<uint64_t> &Record,
1479                                            unsigned Abbrev) {
1480   Record.push_back(N->isDistinct());
1481   Record.push_back(N->getTag());
1482   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1483   Record.push_back(N->getSizeInBits());
1484   Record.push_back(N->getAlignInBits());
1485   Record.push_back(N->getEncoding());
1486 
1487   Stream.EmitRecord(bitc::METADATA_BASIC_TYPE, Record, Abbrev);
1488   Record.clear();
1489 }
1490 
1491 void ModuleBitcodeWriter::writeDIDerivedType(const DIDerivedType *N,
1492                                              SmallVectorImpl<uint64_t> &Record,
1493                                              unsigned Abbrev) {
1494   Record.push_back(N->isDistinct());
1495   Record.push_back(N->getTag());
1496   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1497   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1498   Record.push_back(N->getLine());
1499   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1500   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1501   Record.push_back(N->getSizeInBits());
1502   Record.push_back(N->getAlignInBits());
1503   Record.push_back(N->getOffsetInBits());
1504   Record.push_back(N->getFlags());
1505   Record.push_back(VE.getMetadataOrNullID(N->getExtraData()));
1506 
1507   // DWARF address space is encoded as N->getDWARFAddressSpace() + 1. 0 means
1508   // that there is no DWARF address space associated with DIDerivedType.
1509   if (const auto &DWARFAddressSpace = N->getDWARFAddressSpace())
1510     Record.push_back(*DWARFAddressSpace + 1);
1511   else
1512     Record.push_back(0);
1513 
1514   Stream.EmitRecord(bitc::METADATA_DERIVED_TYPE, Record, Abbrev);
1515   Record.clear();
1516 }
1517 
1518 void ModuleBitcodeWriter::writeDICompositeType(
1519     const DICompositeType *N, SmallVectorImpl<uint64_t> &Record,
1520     unsigned Abbrev) {
1521   const unsigned IsNotUsedInOldTypeRef = 0x2;
1522   Record.push_back(IsNotUsedInOldTypeRef | (unsigned)N->isDistinct());
1523   Record.push_back(N->getTag());
1524   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1525   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1526   Record.push_back(N->getLine());
1527   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1528   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1529   Record.push_back(N->getSizeInBits());
1530   Record.push_back(N->getAlignInBits());
1531   Record.push_back(N->getOffsetInBits());
1532   Record.push_back(N->getFlags());
1533   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1534   Record.push_back(N->getRuntimeLang());
1535   Record.push_back(VE.getMetadataOrNullID(N->getVTableHolder()));
1536   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1537   Record.push_back(VE.getMetadataOrNullID(N->getRawIdentifier()));
1538   Record.push_back(VE.getMetadataOrNullID(N->getDiscriminator()));
1539 
1540   Stream.EmitRecord(bitc::METADATA_COMPOSITE_TYPE, Record, Abbrev);
1541   Record.clear();
1542 }
1543 
1544 void ModuleBitcodeWriter::writeDISubroutineType(
1545     const DISubroutineType *N, SmallVectorImpl<uint64_t> &Record,
1546     unsigned Abbrev) {
1547   const unsigned HasNoOldTypeRefs = 0x2;
1548   Record.push_back(HasNoOldTypeRefs | (unsigned)N->isDistinct());
1549   Record.push_back(N->getFlags());
1550   Record.push_back(VE.getMetadataOrNullID(N->getTypeArray().get()));
1551   Record.push_back(N->getCC());
1552 
1553   Stream.EmitRecord(bitc::METADATA_SUBROUTINE_TYPE, Record, Abbrev);
1554   Record.clear();
1555 }
1556 
1557 void ModuleBitcodeWriter::writeDIFile(const DIFile *N,
1558                                       SmallVectorImpl<uint64_t> &Record,
1559                                       unsigned Abbrev) {
1560   Record.push_back(N->isDistinct());
1561   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
1562   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
1563   if (N->getRawChecksum()) {
1564     Record.push_back(N->getRawChecksum()->Kind);
1565     Record.push_back(VE.getMetadataOrNullID(N->getRawChecksum()->Value));
1566   } else {
1567     // Maintain backwards compatibility with the old internal representation of
1568     // CSK_None in ChecksumKind by writing nulls here when Checksum is None.
1569     Record.push_back(0);
1570     Record.push_back(VE.getMetadataOrNullID(nullptr));
1571   }
1572   auto Source = N->getRawSource();
1573   if (Source)
1574     Record.push_back(VE.getMetadataOrNullID(*Source));
1575 
1576   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
1577   Record.clear();
1578 }
1579 
1580 void ModuleBitcodeWriter::writeDICompileUnit(const DICompileUnit *N,
1581                                              SmallVectorImpl<uint64_t> &Record,
1582                                              unsigned Abbrev) {
1583   assert(N->isDistinct() && "Expected distinct compile units");
1584   Record.push_back(/* IsDistinct */ true);
1585   Record.push_back(N->getSourceLanguage());
1586   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1587   Record.push_back(VE.getMetadataOrNullID(N->getRawProducer()));
1588   Record.push_back(N->isOptimized());
1589   Record.push_back(VE.getMetadataOrNullID(N->getRawFlags()));
1590   Record.push_back(N->getRuntimeVersion());
1591   Record.push_back(VE.getMetadataOrNullID(N->getRawSplitDebugFilename()));
1592   Record.push_back(N->getEmissionKind());
1593   Record.push_back(VE.getMetadataOrNullID(N->getEnumTypes().get()));
1594   Record.push_back(VE.getMetadataOrNullID(N->getRetainedTypes().get()));
1595   Record.push_back(/* subprograms */ 0);
1596   Record.push_back(VE.getMetadataOrNullID(N->getGlobalVariables().get()));
1597   Record.push_back(VE.getMetadataOrNullID(N->getImportedEntities().get()));
1598   Record.push_back(N->getDWOId());
1599   Record.push_back(VE.getMetadataOrNullID(N->getMacros().get()));
1600   Record.push_back(N->getSplitDebugInlining());
1601   Record.push_back(N->getDebugInfoForProfiling());
1602   Record.push_back(N->getGnuPubnames());
1603 
1604   Stream.EmitRecord(bitc::METADATA_COMPILE_UNIT, Record, Abbrev);
1605   Record.clear();
1606 }
1607 
1608 void ModuleBitcodeWriter::writeDISubprogram(const DISubprogram *N,
1609                                             SmallVectorImpl<uint64_t> &Record,
1610                                             unsigned Abbrev) {
1611   uint64_t HasUnitFlag = 1 << 1;
1612   Record.push_back(N->isDistinct() | HasUnitFlag);
1613   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1614   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1615   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1616   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1617   Record.push_back(N->getLine());
1618   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1619   Record.push_back(N->isLocalToUnit());
1620   Record.push_back(N->isDefinition());
1621   Record.push_back(N->getScopeLine());
1622   Record.push_back(VE.getMetadataOrNullID(N->getContainingType()));
1623   Record.push_back(N->getVirtuality());
1624   Record.push_back(N->getVirtualIndex());
1625   Record.push_back(N->getFlags());
1626   Record.push_back(N->isOptimized());
1627   Record.push_back(VE.getMetadataOrNullID(N->getRawUnit()));
1628   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1629   Record.push_back(VE.getMetadataOrNullID(N->getDeclaration()));
1630   Record.push_back(VE.getMetadataOrNullID(N->getVariables().get()));
1631   Record.push_back(N->getThisAdjustment());
1632   Record.push_back(VE.getMetadataOrNullID(N->getThrownTypes().get()));
1633 
1634   Stream.EmitRecord(bitc::METADATA_SUBPROGRAM, Record, Abbrev);
1635   Record.clear();
1636 }
1637 
1638 void ModuleBitcodeWriter::writeDILexicalBlock(const DILexicalBlock *N,
1639                                               SmallVectorImpl<uint64_t> &Record,
1640                                               unsigned Abbrev) {
1641   Record.push_back(N->isDistinct());
1642   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1643   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1644   Record.push_back(N->getLine());
1645   Record.push_back(N->getColumn());
1646 
1647   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK, Record, Abbrev);
1648   Record.clear();
1649 }
1650 
1651 void ModuleBitcodeWriter::writeDILexicalBlockFile(
1652     const DILexicalBlockFile *N, SmallVectorImpl<uint64_t> &Record,
1653     unsigned Abbrev) {
1654   Record.push_back(N->isDistinct());
1655   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1656   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1657   Record.push_back(N->getDiscriminator());
1658 
1659   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK_FILE, Record, Abbrev);
1660   Record.clear();
1661 }
1662 
1663 void ModuleBitcodeWriter::writeDINamespace(const DINamespace *N,
1664                                            SmallVectorImpl<uint64_t> &Record,
1665                                            unsigned Abbrev) {
1666   Record.push_back(N->isDistinct() | N->getExportSymbols() << 1);
1667   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1668   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1669 
1670   Stream.EmitRecord(bitc::METADATA_NAMESPACE, Record, Abbrev);
1671   Record.clear();
1672 }
1673 
1674 void ModuleBitcodeWriter::writeDIMacro(const DIMacro *N,
1675                                        SmallVectorImpl<uint64_t> &Record,
1676                                        unsigned Abbrev) {
1677   Record.push_back(N->isDistinct());
1678   Record.push_back(N->getMacinfoType());
1679   Record.push_back(N->getLine());
1680   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1681   Record.push_back(VE.getMetadataOrNullID(N->getRawValue()));
1682 
1683   Stream.EmitRecord(bitc::METADATA_MACRO, Record, Abbrev);
1684   Record.clear();
1685 }
1686 
1687 void ModuleBitcodeWriter::writeDIMacroFile(const DIMacroFile *N,
1688                                            SmallVectorImpl<uint64_t> &Record,
1689                                            unsigned Abbrev) {
1690   Record.push_back(N->isDistinct());
1691   Record.push_back(N->getMacinfoType());
1692   Record.push_back(N->getLine());
1693   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1694   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1695 
1696   Stream.EmitRecord(bitc::METADATA_MACRO_FILE, Record, Abbrev);
1697   Record.clear();
1698 }
1699 
1700 void ModuleBitcodeWriter::writeDIModule(const DIModule *N,
1701                                         SmallVectorImpl<uint64_t> &Record,
1702                                         unsigned Abbrev) {
1703   Record.push_back(N->isDistinct());
1704   for (auto &I : N->operands())
1705     Record.push_back(VE.getMetadataOrNullID(I));
1706 
1707   Stream.EmitRecord(bitc::METADATA_MODULE, Record, Abbrev);
1708   Record.clear();
1709 }
1710 
1711 void ModuleBitcodeWriter::writeDITemplateTypeParameter(
1712     const DITemplateTypeParameter *N, SmallVectorImpl<uint64_t> &Record,
1713     unsigned Abbrev) {
1714   Record.push_back(N->isDistinct());
1715   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1716   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1717 
1718   Stream.EmitRecord(bitc::METADATA_TEMPLATE_TYPE, Record, Abbrev);
1719   Record.clear();
1720 }
1721 
1722 void ModuleBitcodeWriter::writeDITemplateValueParameter(
1723     const DITemplateValueParameter *N, SmallVectorImpl<uint64_t> &Record,
1724     unsigned Abbrev) {
1725   Record.push_back(N->isDistinct());
1726   Record.push_back(N->getTag());
1727   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1728   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1729   Record.push_back(VE.getMetadataOrNullID(N->getValue()));
1730 
1731   Stream.EmitRecord(bitc::METADATA_TEMPLATE_VALUE, Record, Abbrev);
1732   Record.clear();
1733 }
1734 
1735 void ModuleBitcodeWriter::writeDIGlobalVariable(
1736     const DIGlobalVariable *N, SmallVectorImpl<uint64_t> &Record,
1737     unsigned Abbrev) {
1738   const uint64_t Version = 1 << 1;
1739   Record.push_back((uint64_t)N->isDistinct() | Version);
1740   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1741   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1742   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1743   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1744   Record.push_back(N->getLine());
1745   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1746   Record.push_back(N->isLocalToUnit());
1747   Record.push_back(N->isDefinition());
1748   Record.push_back(/* expr */ 0);
1749   Record.push_back(VE.getMetadataOrNullID(N->getStaticDataMemberDeclaration()));
1750   Record.push_back(N->getAlignInBits());
1751 
1752   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR, Record, Abbrev);
1753   Record.clear();
1754 }
1755 
1756 void ModuleBitcodeWriter::writeDILocalVariable(
1757     const DILocalVariable *N, SmallVectorImpl<uint64_t> &Record,
1758     unsigned Abbrev) {
1759   // In order to support all possible bitcode formats in BitcodeReader we need
1760   // to distinguish the following cases:
1761   // 1) Record has no artificial tag (Record[1]),
1762   //   has no obsolete inlinedAt field (Record[9]).
1763   //   In this case Record size will be 8, HasAlignment flag is false.
1764   // 2) Record has artificial tag (Record[1]),
1765   //   has no obsolete inlignedAt field (Record[9]).
1766   //   In this case Record size will be 9, HasAlignment flag is false.
1767   // 3) Record has both artificial tag (Record[1]) and
1768   //   obsolete inlignedAt field (Record[9]).
1769   //   In this case Record size will be 10, HasAlignment flag is false.
1770   // 4) Record has neither artificial tag, nor inlignedAt field, but
1771   //   HasAlignment flag is true and Record[8] contains alignment value.
1772   const uint64_t HasAlignmentFlag = 1 << 1;
1773   Record.push_back((uint64_t)N->isDistinct() | HasAlignmentFlag);
1774   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1775   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1776   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1777   Record.push_back(N->getLine());
1778   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1779   Record.push_back(N->getArg());
1780   Record.push_back(N->getFlags());
1781   Record.push_back(N->getAlignInBits());
1782 
1783   Stream.EmitRecord(bitc::METADATA_LOCAL_VAR, Record, Abbrev);
1784   Record.clear();
1785 }
1786 
1787 void ModuleBitcodeWriter::writeDIExpression(const DIExpression *N,
1788                                             SmallVectorImpl<uint64_t> &Record,
1789                                             unsigned Abbrev) {
1790   Record.reserve(N->getElements().size() + 1);
1791   const uint64_t Version = 3 << 1;
1792   Record.push_back((uint64_t)N->isDistinct() | Version);
1793   Record.append(N->elements_begin(), N->elements_end());
1794 
1795   Stream.EmitRecord(bitc::METADATA_EXPRESSION, Record, Abbrev);
1796   Record.clear();
1797 }
1798 
1799 void ModuleBitcodeWriter::writeDIGlobalVariableExpression(
1800     const DIGlobalVariableExpression *N, SmallVectorImpl<uint64_t> &Record,
1801     unsigned Abbrev) {
1802   Record.push_back(N->isDistinct());
1803   Record.push_back(VE.getMetadataOrNullID(N->getVariable()));
1804   Record.push_back(VE.getMetadataOrNullID(N->getExpression()));
1805 
1806   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR_EXPR, Record, Abbrev);
1807   Record.clear();
1808 }
1809 
1810 void ModuleBitcodeWriter::writeDIObjCProperty(const DIObjCProperty *N,
1811                                               SmallVectorImpl<uint64_t> &Record,
1812                                               unsigned Abbrev) {
1813   Record.push_back(N->isDistinct());
1814   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1815   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1816   Record.push_back(N->getLine());
1817   Record.push_back(VE.getMetadataOrNullID(N->getRawSetterName()));
1818   Record.push_back(VE.getMetadataOrNullID(N->getRawGetterName()));
1819   Record.push_back(N->getAttributes());
1820   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1821 
1822   Stream.EmitRecord(bitc::METADATA_OBJC_PROPERTY, Record, Abbrev);
1823   Record.clear();
1824 }
1825 
1826 void ModuleBitcodeWriter::writeDIImportedEntity(
1827     const DIImportedEntity *N, SmallVectorImpl<uint64_t> &Record,
1828     unsigned Abbrev) {
1829   Record.push_back(N->isDistinct());
1830   Record.push_back(N->getTag());
1831   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1832   Record.push_back(VE.getMetadataOrNullID(N->getEntity()));
1833   Record.push_back(N->getLine());
1834   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1835   Record.push_back(VE.getMetadataOrNullID(N->getRawFile()));
1836 
1837   Stream.EmitRecord(bitc::METADATA_IMPORTED_ENTITY, Record, Abbrev);
1838   Record.clear();
1839 }
1840 
1841 unsigned ModuleBitcodeWriter::createNamedMetadataAbbrev() {
1842   auto Abbv = std::make_shared<BitCodeAbbrev>();
1843   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
1844   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1845   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1846   return Stream.EmitAbbrev(std::move(Abbv));
1847 }
1848 
1849 void ModuleBitcodeWriter::writeNamedMetadata(
1850     SmallVectorImpl<uint64_t> &Record) {
1851   if (M.named_metadata_empty())
1852     return;
1853 
1854   unsigned Abbrev = createNamedMetadataAbbrev();
1855   for (const NamedMDNode &NMD : M.named_metadata()) {
1856     // Write name.
1857     StringRef Str = NMD.getName();
1858     Record.append(Str.bytes_begin(), Str.bytes_end());
1859     Stream.EmitRecord(bitc::METADATA_NAME, Record, Abbrev);
1860     Record.clear();
1861 
1862     // Write named metadata operands.
1863     for (const MDNode *N : NMD.operands())
1864       Record.push_back(VE.getMetadataID(N));
1865     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
1866     Record.clear();
1867   }
1868 }
1869 
1870 unsigned ModuleBitcodeWriter::createMetadataStringsAbbrev() {
1871   auto Abbv = std::make_shared<BitCodeAbbrev>();
1872   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRINGS));
1873   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // # of strings
1874   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // offset to chars
1875   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
1876   return Stream.EmitAbbrev(std::move(Abbv));
1877 }
1878 
1879 /// Write out a record for MDString.
1880 ///
1881 /// All the metadata strings in a metadata block are emitted in a single
1882 /// record.  The sizes and strings themselves are shoved into a blob.
1883 void ModuleBitcodeWriter::writeMetadataStrings(
1884     ArrayRef<const Metadata *> Strings, SmallVectorImpl<uint64_t> &Record) {
1885   if (Strings.empty())
1886     return;
1887 
1888   // Start the record with the number of strings.
1889   Record.push_back(bitc::METADATA_STRINGS);
1890   Record.push_back(Strings.size());
1891 
1892   // Emit the sizes of the strings in the blob.
1893   SmallString<256> Blob;
1894   {
1895     BitstreamWriter W(Blob);
1896     for (const Metadata *MD : Strings)
1897       W.EmitVBR(cast<MDString>(MD)->getLength(), 6);
1898     W.FlushToWord();
1899   }
1900 
1901   // Add the offset to the strings to the record.
1902   Record.push_back(Blob.size());
1903 
1904   // Add the strings to the blob.
1905   for (const Metadata *MD : Strings)
1906     Blob.append(cast<MDString>(MD)->getString());
1907 
1908   // Emit the final record.
1909   Stream.EmitRecordWithBlob(createMetadataStringsAbbrev(), Record, Blob);
1910   Record.clear();
1911 }
1912 
1913 // Generates an enum to use as an index in the Abbrev array of Metadata record.
1914 enum MetadataAbbrev : unsigned {
1915 #define HANDLE_MDNODE_LEAF(CLASS) CLASS##AbbrevID,
1916 #include "llvm/IR/Metadata.def"
1917   LastPlusOne
1918 };
1919 
1920 void ModuleBitcodeWriter::writeMetadataRecords(
1921     ArrayRef<const Metadata *> MDs, SmallVectorImpl<uint64_t> &Record,
1922     std::vector<unsigned> *MDAbbrevs, std::vector<uint64_t> *IndexPos) {
1923   if (MDs.empty())
1924     return;
1925 
1926   // Initialize MDNode abbreviations.
1927 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
1928 #include "llvm/IR/Metadata.def"
1929 
1930   for (const Metadata *MD : MDs) {
1931     if (IndexPos)
1932       IndexPos->push_back(Stream.GetCurrentBitNo());
1933     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
1934       assert(N->isResolved() && "Expected forward references to be resolved");
1935 
1936       switch (N->getMetadataID()) {
1937       default:
1938         llvm_unreachable("Invalid MDNode subclass");
1939 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
1940   case Metadata::CLASS##Kind:                                                  \
1941     if (MDAbbrevs)                                                             \
1942       write##CLASS(cast<CLASS>(N), Record,                                     \
1943                    (*MDAbbrevs)[MetadataAbbrev::CLASS##AbbrevID]);             \
1944     else                                                                       \
1945       write##CLASS(cast<CLASS>(N), Record, CLASS##Abbrev);                     \
1946     continue;
1947 #include "llvm/IR/Metadata.def"
1948       }
1949     }
1950     writeValueAsMetadata(cast<ValueAsMetadata>(MD), Record);
1951   }
1952 }
1953 
1954 void ModuleBitcodeWriter::writeModuleMetadata() {
1955   if (!VE.hasMDs() && M.named_metadata_empty())
1956     return;
1957 
1958   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 4);
1959   SmallVector<uint64_t, 64> Record;
1960 
1961   // Emit all abbrevs upfront, so that the reader can jump in the middle of the
1962   // block and load any metadata.
1963   std::vector<unsigned> MDAbbrevs;
1964 
1965   MDAbbrevs.resize(MetadataAbbrev::LastPlusOne);
1966   MDAbbrevs[MetadataAbbrev::DILocationAbbrevID] = createDILocationAbbrev();
1967   MDAbbrevs[MetadataAbbrev::GenericDINodeAbbrevID] =
1968       createGenericDINodeAbbrev();
1969 
1970   auto Abbv = std::make_shared<BitCodeAbbrev>();
1971   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX_OFFSET));
1972   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
1973   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
1974   unsigned OffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1975 
1976   Abbv = std::make_shared<BitCodeAbbrev>();
1977   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX));
1978   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1979   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1980   unsigned IndexAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1981 
1982   // Emit MDStrings together upfront.
1983   writeMetadataStrings(VE.getMDStrings(), Record);
1984 
1985   // We only emit an index for the metadata record if we have more than a given
1986   // (naive) threshold of metadatas, otherwise it is not worth it.
1987   if (VE.getNonMDStrings().size() > IndexThreshold) {
1988     // Write a placeholder value in for the offset of the metadata index,
1989     // which is written after the records, so that it can include
1990     // the offset of each entry. The placeholder offset will be
1991     // updated after all records are emitted.
1992     uint64_t Vals[] = {0, 0};
1993     Stream.EmitRecord(bitc::METADATA_INDEX_OFFSET, Vals, OffsetAbbrev);
1994   }
1995 
1996   // Compute and save the bit offset to the current position, which will be
1997   // patched when we emit the index later. We can simply subtract the 64-bit
1998   // fixed size from the current bit number to get the location to backpatch.
1999   uint64_t IndexOffsetRecordBitPos = Stream.GetCurrentBitNo();
2000 
2001   // This index will contain the bitpos for each individual record.
2002   std::vector<uint64_t> IndexPos;
2003   IndexPos.reserve(VE.getNonMDStrings().size());
2004 
2005   // Write all the records
2006   writeMetadataRecords(VE.getNonMDStrings(), Record, &MDAbbrevs, &IndexPos);
2007 
2008   if (VE.getNonMDStrings().size() > IndexThreshold) {
2009     // Now that we have emitted all the records we will emit the index. But
2010     // first
2011     // backpatch the forward reference so that the reader can skip the records
2012     // efficiently.
2013     Stream.BackpatchWord64(IndexOffsetRecordBitPos - 64,
2014                            Stream.GetCurrentBitNo() - IndexOffsetRecordBitPos);
2015 
2016     // Delta encode the index.
2017     uint64_t PreviousValue = IndexOffsetRecordBitPos;
2018     for (auto &Elt : IndexPos) {
2019       auto EltDelta = Elt - PreviousValue;
2020       PreviousValue = Elt;
2021       Elt = EltDelta;
2022     }
2023     // Emit the index record.
2024     Stream.EmitRecord(bitc::METADATA_INDEX, IndexPos, IndexAbbrev);
2025     IndexPos.clear();
2026   }
2027 
2028   // Write the named metadata now.
2029   writeNamedMetadata(Record);
2030 
2031   auto AddDeclAttachedMetadata = [&](const GlobalObject &GO) {
2032     SmallVector<uint64_t, 4> Record;
2033     Record.push_back(VE.getValueID(&GO));
2034     pushGlobalMetadataAttachment(Record, GO);
2035     Stream.EmitRecord(bitc::METADATA_GLOBAL_DECL_ATTACHMENT, Record);
2036   };
2037   for (const Function &F : M)
2038     if (F.isDeclaration() && F.hasMetadata())
2039       AddDeclAttachedMetadata(F);
2040   // FIXME: Only store metadata for declarations here, and move data for global
2041   // variable definitions to a separate block (PR28134).
2042   for (const GlobalVariable &GV : M.globals())
2043     if (GV.hasMetadata())
2044       AddDeclAttachedMetadata(GV);
2045 
2046   Stream.ExitBlock();
2047 }
2048 
2049 void ModuleBitcodeWriter::writeFunctionMetadata(const Function &F) {
2050   if (!VE.hasMDs())
2051     return;
2052 
2053   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
2054   SmallVector<uint64_t, 64> Record;
2055   writeMetadataStrings(VE.getMDStrings(), Record);
2056   writeMetadataRecords(VE.getNonMDStrings(), Record);
2057   Stream.ExitBlock();
2058 }
2059 
2060 void ModuleBitcodeWriter::pushGlobalMetadataAttachment(
2061     SmallVectorImpl<uint64_t> &Record, const GlobalObject &GO) {
2062   // [n x [id, mdnode]]
2063   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2064   GO.getAllMetadata(MDs);
2065   for (const auto &I : MDs) {
2066     Record.push_back(I.first);
2067     Record.push_back(VE.getMetadataID(I.second));
2068   }
2069 }
2070 
2071 void ModuleBitcodeWriter::writeFunctionMetadataAttachment(const Function &F) {
2072   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
2073 
2074   SmallVector<uint64_t, 64> Record;
2075 
2076   if (F.hasMetadata()) {
2077     pushGlobalMetadataAttachment(Record, F);
2078     Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2079     Record.clear();
2080   }
2081 
2082   // Write metadata attachments
2083   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
2084   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2085   for (const BasicBlock &BB : F)
2086     for (const Instruction &I : BB) {
2087       MDs.clear();
2088       I.getAllMetadataOtherThanDebugLoc(MDs);
2089 
2090       // If no metadata, ignore instruction.
2091       if (MDs.empty()) continue;
2092 
2093       Record.push_back(VE.getInstructionID(&I));
2094 
2095       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
2096         Record.push_back(MDs[i].first);
2097         Record.push_back(VE.getMetadataID(MDs[i].second));
2098       }
2099       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2100       Record.clear();
2101     }
2102 
2103   Stream.ExitBlock();
2104 }
2105 
2106 void ModuleBitcodeWriter::writeModuleMetadataKinds() {
2107   SmallVector<uint64_t, 64> Record;
2108 
2109   // Write metadata kinds
2110   // METADATA_KIND - [n x [id, name]]
2111   SmallVector<StringRef, 8> Names;
2112   M.getMDKindNames(Names);
2113 
2114   if (Names.empty()) return;
2115 
2116   Stream.EnterSubblock(bitc::METADATA_KIND_BLOCK_ID, 3);
2117 
2118   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
2119     Record.push_back(MDKindID);
2120     StringRef KName = Names[MDKindID];
2121     Record.append(KName.begin(), KName.end());
2122 
2123     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
2124     Record.clear();
2125   }
2126 
2127   Stream.ExitBlock();
2128 }
2129 
2130 void ModuleBitcodeWriter::writeOperandBundleTags() {
2131   // Write metadata kinds
2132   //
2133   // OPERAND_BUNDLE_TAGS_BLOCK_ID : N x OPERAND_BUNDLE_TAG
2134   //
2135   // OPERAND_BUNDLE_TAG - [strchr x N]
2136 
2137   SmallVector<StringRef, 8> Tags;
2138   M.getOperandBundleTags(Tags);
2139 
2140   if (Tags.empty())
2141     return;
2142 
2143   Stream.EnterSubblock(bitc::OPERAND_BUNDLE_TAGS_BLOCK_ID, 3);
2144 
2145   SmallVector<uint64_t, 64> Record;
2146 
2147   for (auto Tag : Tags) {
2148     Record.append(Tag.begin(), Tag.end());
2149 
2150     Stream.EmitRecord(bitc::OPERAND_BUNDLE_TAG, Record, 0);
2151     Record.clear();
2152   }
2153 
2154   Stream.ExitBlock();
2155 }
2156 
2157 void ModuleBitcodeWriter::writeSyncScopeNames() {
2158   SmallVector<StringRef, 8> SSNs;
2159   M.getContext().getSyncScopeNames(SSNs);
2160   if (SSNs.empty())
2161     return;
2162 
2163   Stream.EnterSubblock(bitc::SYNC_SCOPE_NAMES_BLOCK_ID, 2);
2164 
2165   SmallVector<uint64_t, 64> Record;
2166   for (auto SSN : SSNs) {
2167     Record.append(SSN.begin(), SSN.end());
2168     Stream.EmitRecord(bitc::SYNC_SCOPE_NAME, Record, 0);
2169     Record.clear();
2170   }
2171 
2172   Stream.ExitBlock();
2173 }
2174 
2175 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
2176   if ((int64_t)V >= 0)
2177     Vals.push_back(V << 1);
2178   else
2179     Vals.push_back((-V << 1) | 1);
2180 }
2181 
2182 void ModuleBitcodeWriter::writeConstants(unsigned FirstVal, unsigned LastVal,
2183                                          bool isGlobal) {
2184   if (FirstVal == LastVal) return;
2185 
2186   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
2187 
2188   unsigned AggregateAbbrev = 0;
2189   unsigned String8Abbrev = 0;
2190   unsigned CString7Abbrev = 0;
2191   unsigned CString6Abbrev = 0;
2192   // If this is a constant pool for the module, emit module-specific abbrevs.
2193   if (isGlobal) {
2194     // Abbrev for CST_CODE_AGGREGATE.
2195     auto Abbv = std::make_shared<BitCodeAbbrev>();
2196     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
2197     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2198     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
2199     AggregateAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2200 
2201     // Abbrev for CST_CODE_STRING.
2202     Abbv = std::make_shared<BitCodeAbbrev>();
2203     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
2204     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2205     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2206     String8Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2207     // Abbrev for CST_CODE_CSTRING.
2208     Abbv = std::make_shared<BitCodeAbbrev>();
2209     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2210     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2211     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2212     CString7Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2213     // Abbrev for CST_CODE_CSTRING.
2214     Abbv = std::make_shared<BitCodeAbbrev>();
2215     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2216     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2217     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2218     CString6Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2219   }
2220 
2221   SmallVector<uint64_t, 64> Record;
2222 
2223   const ValueEnumerator::ValueList &Vals = VE.getValues();
2224   Type *LastTy = nullptr;
2225   for (unsigned i = FirstVal; i != LastVal; ++i) {
2226     const Value *V = Vals[i].first;
2227     // If we need to switch types, do so now.
2228     if (V->getType() != LastTy) {
2229       LastTy = V->getType();
2230       Record.push_back(VE.getTypeID(LastTy));
2231       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
2232                         CONSTANTS_SETTYPE_ABBREV);
2233       Record.clear();
2234     }
2235 
2236     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
2237       Record.push_back(unsigned(IA->hasSideEffects()) |
2238                        unsigned(IA->isAlignStack()) << 1 |
2239                        unsigned(IA->getDialect()&1) << 2);
2240 
2241       // Add the asm string.
2242       const std::string &AsmStr = IA->getAsmString();
2243       Record.push_back(AsmStr.size());
2244       Record.append(AsmStr.begin(), AsmStr.end());
2245 
2246       // Add the constraint string.
2247       const std::string &ConstraintStr = IA->getConstraintString();
2248       Record.push_back(ConstraintStr.size());
2249       Record.append(ConstraintStr.begin(), ConstraintStr.end());
2250       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
2251       Record.clear();
2252       continue;
2253     }
2254     const Constant *C = cast<Constant>(V);
2255     unsigned Code = -1U;
2256     unsigned AbbrevToUse = 0;
2257     if (C->isNullValue()) {
2258       Code = bitc::CST_CODE_NULL;
2259     } else if (isa<UndefValue>(C)) {
2260       Code = bitc::CST_CODE_UNDEF;
2261     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
2262       if (IV->getBitWidth() <= 64) {
2263         uint64_t V = IV->getSExtValue();
2264         emitSignedInt64(Record, V);
2265         Code = bitc::CST_CODE_INTEGER;
2266         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
2267       } else {                             // Wide integers, > 64 bits in size.
2268         // We have an arbitrary precision integer value to write whose
2269         // bit width is > 64. However, in canonical unsigned integer
2270         // format it is likely that the high bits are going to be zero.
2271         // So, we only write the number of active words.
2272         unsigned NWords = IV->getValue().getActiveWords();
2273         const uint64_t *RawWords = IV->getValue().getRawData();
2274         for (unsigned i = 0; i != NWords; ++i) {
2275           emitSignedInt64(Record, RawWords[i]);
2276         }
2277         Code = bitc::CST_CODE_WIDE_INTEGER;
2278       }
2279     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
2280       Code = bitc::CST_CODE_FLOAT;
2281       Type *Ty = CFP->getType();
2282       if (Ty->isHalfTy() || Ty->isFloatTy() || Ty->isDoubleTy()) {
2283         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
2284       } else if (Ty->isX86_FP80Ty()) {
2285         // api needed to prevent premature destruction
2286         // bits are not in the same order as a normal i80 APInt, compensate.
2287         APInt api = CFP->getValueAPF().bitcastToAPInt();
2288         const uint64_t *p = api.getRawData();
2289         Record.push_back((p[1] << 48) | (p[0] >> 16));
2290         Record.push_back(p[0] & 0xffffLL);
2291       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
2292         APInt api = CFP->getValueAPF().bitcastToAPInt();
2293         const uint64_t *p = api.getRawData();
2294         Record.push_back(p[0]);
2295         Record.push_back(p[1]);
2296       } else {
2297         assert(0 && "Unknown FP type!");
2298       }
2299     } else if (isa<ConstantDataSequential>(C) &&
2300                cast<ConstantDataSequential>(C)->isString()) {
2301       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
2302       // Emit constant strings specially.
2303       unsigned NumElts = Str->getNumElements();
2304       // If this is a null-terminated string, use the denser CSTRING encoding.
2305       if (Str->isCString()) {
2306         Code = bitc::CST_CODE_CSTRING;
2307         --NumElts;  // Don't encode the null, which isn't allowed by char6.
2308       } else {
2309         Code = bitc::CST_CODE_STRING;
2310         AbbrevToUse = String8Abbrev;
2311       }
2312       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
2313       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
2314       for (unsigned i = 0; i != NumElts; ++i) {
2315         unsigned char V = Str->getElementAsInteger(i);
2316         Record.push_back(V);
2317         isCStr7 &= (V & 128) == 0;
2318         if (isCStrChar6)
2319           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
2320       }
2321 
2322       if (isCStrChar6)
2323         AbbrevToUse = CString6Abbrev;
2324       else if (isCStr7)
2325         AbbrevToUse = CString7Abbrev;
2326     } else if (const ConstantDataSequential *CDS =
2327                   dyn_cast<ConstantDataSequential>(C)) {
2328       Code = bitc::CST_CODE_DATA;
2329       Type *EltTy = CDS->getType()->getElementType();
2330       if (isa<IntegerType>(EltTy)) {
2331         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2332           Record.push_back(CDS->getElementAsInteger(i));
2333       } else {
2334         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2335           Record.push_back(
2336               CDS->getElementAsAPFloat(i).bitcastToAPInt().getLimitedValue());
2337       }
2338     } else if (isa<ConstantAggregate>(C)) {
2339       Code = bitc::CST_CODE_AGGREGATE;
2340       for (const Value *Op : C->operands())
2341         Record.push_back(VE.getValueID(Op));
2342       AbbrevToUse = AggregateAbbrev;
2343     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
2344       switch (CE->getOpcode()) {
2345       default:
2346         if (Instruction::isCast(CE->getOpcode())) {
2347           Code = bitc::CST_CODE_CE_CAST;
2348           Record.push_back(getEncodedCastOpcode(CE->getOpcode()));
2349           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2350           Record.push_back(VE.getValueID(C->getOperand(0)));
2351           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
2352         } else {
2353           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
2354           Code = bitc::CST_CODE_CE_BINOP;
2355           Record.push_back(getEncodedBinaryOpcode(CE->getOpcode()));
2356           Record.push_back(VE.getValueID(C->getOperand(0)));
2357           Record.push_back(VE.getValueID(C->getOperand(1)));
2358           uint64_t Flags = getOptimizationFlags(CE);
2359           if (Flags != 0)
2360             Record.push_back(Flags);
2361         }
2362         break;
2363       case Instruction::GetElementPtr: {
2364         Code = bitc::CST_CODE_CE_GEP;
2365         const auto *GO = cast<GEPOperator>(C);
2366         Record.push_back(VE.getTypeID(GO->getSourceElementType()));
2367         if (Optional<unsigned> Idx = GO->getInRangeIndex()) {
2368           Code = bitc::CST_CODE_CE_GEP_WITH_INRANGE_INDEX;
2369           Record.push_back((*Idx << 1) | GO->isInBounds());
2370         } else if (GO->isInBounds())
2371           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
2372         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
2373           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
2374           Record.push_back(VE.getValueID(C->getOperand(i)));
2375         }
2376         break;
2377       }
2378       case Instruction::Select:
2379         Code = bitc::CST_CODE_CE_SELECT;
2380         Record.push_back(VE.getValueID(C->getOperand(0)));
2381         Record.push_back(VE.getValueID(C->getOperand(1)));
2382         Record.push_back(VE.getValueID(C->getOperand(2)));
2383         break;
2384       case Instruction::ExtractElement:
2385         Code = bitc::CST_CODE_CE_EXTRACTELT;
2386         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2387         Record.push_back(VE.getValueID(C->getOperand(0)));
2388         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
2389         Record.push_back(VE.getValueID(C->getOperand(1)));
2390         break;
2391       case Instruction::InsertElement:
2392         Code = bitc::CST_CODE_CE_INSERTELT;
2393         Record.push_back(VE.getValueID(C->getOperand(0)));
2394         Record.push_back(VE.getValueID(C->getOperand(1)));
2395         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
2396         Record.push_back(VE.getValueID(C->getOperand(2)));
2397         break;
2398       case Instruction::ShuffleVector:
2399         // If the return type and argument types are the same, this is a
2400         // standard shufflevector instruction.  If the types are different,
2401         // then the shuffle is widening or truncating the input vectors, and
2402         // the argument type must also be encoded.
2403         if (C->getType() == C->getOperand(0)->getType()) {
2404           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
2405         } else {
2406           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
2407           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2408         }
2409         Record.push_back(VE.getValueID(C->getOperand(0)));
2410         Record.push_back(VE.getValueID(C->getOperand(1)));
2411         Record.push_back(VE.getValueID(C->getOperand(2)));
2412         break;
2413       case Instruction::ICmp:
2414       case Instruction::FCmp:
2415         Code = bitc::CST_CODE_CE_CMP;
2416         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2417         Record.push_back(VE.getValueID(C->getOperand(0)));
2418         Record.push_back(VE.getValueID(C->getOperand(1)));
2419         Record.push_back(CE->getPredicate());
2420         break;
2421       }
2422     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
2423       Code = bitc::CST_CODE_BLOCKADDRESS;
2424       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
2425       Record.push_back(VE.getValueID(BA->getFunction()));
2426       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
2427     } else {
2428 #ifndef NDEBUG
2429       C->dump();
2430 #endif
2431       llvm_unreachable("Unknown constant!");
2432     }
2433     Stream.EmitRecord(Code, Record, AbbrevToUse);
2434     Record.clear();
2435   }
2436 
2437   Stream.ExitBlock();
2438 }
2439 
2440 void ModuleBitcodeWriter::writeModuleConstants() {
2441   const ValueEnumerator::ValueList &Vals = VE.getValues();
2442 
2443   // Find the first constant to emit, which is the first non-globalvalue value.
2444   // We know globalvalues have been emitted by WriteModuleInfo.
2445   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
2446     if (!isa<GlobalValue>(Vals[i].first)) {
2447       writeConstants(i, Vals.size(), true);
2448       return;
2449     }
2450   }
2451 }
2452 
2453 /// pushValueAndType - The file has to encode both the value and type id for
2454 /// many values, because we need to know what type to create for forward
2455 /// references.  However, most operands are not forward references, so this type
2456 /// field is not needed.
2457 ///
2458 /// This function adds V's value ID to Vals.  If the value ID is higher than the
2459 /// instruction ID, then it is a forward reference, and it also includes the
2460 /// type ID.  The value ID that is written is encoded relative to the InstID.
2461 bool ModuleBitcodeWriter::pushValueAndType(const Value *V, unsigned InstID,
2462                                            SmallVectorImpl<unsigned> &Vals) {
2463   unsigned ValID = VE.getValueID(V);
2464   // Make encoding relative to the InstID.
2465   Vals.push_back(InstID - ValID);
2466   if (ValID >= InstID) {
2467     Vals.push_back(VE.getTypeID(V->getType()));
2468     return true;
2469   }
2470   return false;
2471 }
2472 
2473 void ModuleBitcodeWriter::writeOperandBundles(ImmutableCallSite CS,
2474                                               unsigned InstID) {
2475   SmallVector<unsigned, 64> Record;
2476   LLVMContext &C = CS.getInstruction()->getContext();
2477 
2478   for (unsigned i = 0, e = CS.getNumOperandBundles(); i != e; ++i) {
2479     const auto &Bundle = CS.getOperandBundleAt(i);
2480     Record.push_back(C.getOperandBundleTagID(Bundle.getTagName()));
2481 
2482     for (auto &Input : Bundle.Inputs)
2483       pushValueAndType(Input, InstID, Record);
2484 
2485     Stream.EmitRecord(bitc::FUNC_CODE_OPERAND_BUNDLE, Record);
2486     Record.clear();
2487   }
2488 }
2489 
2490 /// pushValue - Like pushValueAndType, but where the type of the value is
2491 /// omitted (perhaps it was already encoded in an earlier operand).
2492 void ModuleBitcodeWriter::pushValue(const Value *V, unsigned InstID,
2493                                     SmallVectorImpl<unsigned> &Vals) {
2494   unsigned ValID = VE.getValueID(V);
2495   Vals.push_back(InstID - ValID);
2496 }
2497 
2498 void ModuleBitcodeWriter::pushValueSigned(const Value *V, unsigned InstID,
2499                                           SmallVectorImpl<uint64_t> &Vals) {
2500   unsigned ValID = VE.getValueID(V);
2501   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
2502   emitSignedInt64(Vals, diff);
2503 }
2504 
2505 /// WriteInstruction - Emit an instruction to the specified stream.
2506 void ModuleBitcodeWriter::writeInstruction(const Instruction &I,
2507                                            unsigned InstID,
2508                                            SmallVectorImpl<unsigned> &Vals) {
2509   unsigned Code = 0;
2510   unsigned AbbrevToUse = 0;
2511   VE.setInstructionID(&I);
2512   switch (I.getOpcode()) {
2513   default:
2514     if (Instruction::isCast(I.getOpcode())) {
2515       Code = bitc::FUNC_CODE_INST_CAST;
2516       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2517         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
2518       Vals.push_back(VE.getTypeID(I.getType()));
2519       Vals.push_back(getEncodedCastOpcode(I.getOpcode()));
2520     } else {
2521       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
2522       Code = bitc::FUNC_CODE_INST_BINOP;
2523       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2524         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
2525       pushValue(I.getOperand(1), InstID, Vals);
2526       Vals.push_back(getEncodedBinaryOpcode(I.getOpcode()));
2527       uint64_t Flags = getOptimizationFlags(&I);
2528       if (Flags != 0) {
2529         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
2530           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
2531         Vals.push_back(Flags);
2532       }
2533     }
2534     break;
2535 
2536   case Instruction::GetElementPtr: {
2537     Code = bitc::FUNC_CODE_INST_GEP;
2538     AbbrevToUse = FUNCTION_INST_GEP_ABBREV;
2539     auto &GEPInst = cast<GetElementPtrInst>(I);
2540     Vals.push_back(GEPInst.isInBounds());
2541     Vals.push_back(VE.getTypeID(GEPInst.getSourceElementType()));
2542     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
2543       pushValueAndType(I.getOperand(i), InstID, Vals);
2544     break;
2545   }
2546   case Instruction::ExtractValue: {
2547     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
2548     pushValueAndType(I.getOperand(0), InstID, Vals);
2549     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
2550     Vals.append(EVI->idx_begin(), EVI->idx_end());
2551     break;
2552   }
2553   case Instruction::InsertValue: {
2554     Code = bitc::FUNC_CODE_INST_INSERTVAL;
2555     pushValueAndType(I.getOperand(0), InstID, Vals);
2556     pushValueAndType(I.getOperand(1), InstID, Vals);
2557     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
2558     Vals.append(IVI->idx_begin(), IVI->idx_end());
2559     break;
2560   }
2561   case Instruction::Select:
2562     Code = bitc::FUNC_CODE_INST_VSELECT;
2563     pushValueAndType(I.getOperand(1), InstID, Vals);
2564     pushValue(I.getOperand(2), InstID, Vals);
2565     pushValueAndType(I.getOperand(0), InstID, Vals);
2566     break;
2567   case Instruction::ExtractElement:
2568     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
2569     pushValueAndType(I.getOperand(0), InstID, Vals);
2570     pushValueAndType(I.getOperand(1), InstID, Vals);
2571     break;
2572   case Instruction::InsertElement:
2573     Code = bitc::FUNC_CODE_INST_INSERTELT;
2574     pushValueAndType(I.getOperand(0), InstID, Vals);
2575     pushValue(I.getOperand(1), InstID, Vals);
2576     pushValueAndType(I.getOperand(2), InstID, Vals);
2577     break;
2578   case Instruction::ShuffleVector:
2579     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
2580     pushValueAndType(I.getOperand(0), InstID, Vals);
2581     pushValue(I.getOperand(1), InstID, Vals);
2582     pushValue(I.getOperand(2), InstID, Vals);
2583     break;
2584   case Instruction::ICmp:
2585   case Instruction::FCmp: {
2586     // compare returning Int1Ty or vector of Int1Ty
2587     Code = bitc::FUNC_CODE_INST_CMP2;
2588     pushValueAndType(I.getOperand(0), InstID, Vals);
2589     pushValue(I.getOperand(1), InstID, Vals);
2590     Vals.push_back(cast<CmpInst>(I).getPredicate());
2591     uint64_t Flags = getOptimizationFlags(&I);
2592     if (Flags != 0)
2593       Vals.push_back(Flags);
2594     break;
2595   }
2596 
2597   case Instruction::Ret:
2598     {
2599       Code = bitc::FUNC_CODE_INST_RET;
2600       unsigned NumOperands = I.getNumOperands();
2601       if (NumOperands == 0)
2602         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
2603       else if (NumOperands == 1) {
2604         if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2605           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
2606       } else {
2607         for (unsigned i = 0, e = NumOperands; i != e; ++i)
2608           pushValueAndType(I.getOperand(i), InstID, Vals);
2609       }
2610     }
2611     break;
2612   case Instruction::Br:
2613     {
2614       Code = bitc::FUNC_CODE_INST_BR;
2615       const BranchInst &II = cast<BranchInst>(I);
2616       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
2617       if (II.isConditional()) {
2618         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
2619         pushValue(II.getCondition(), InstID, Vals);
2620       }
2621     }
2622     break;
2623   case Instruction::Switch:
2624     {
2625       Code = bitc::FUNC_CODE_INST_SWITCH;
2626       const SwitchInst &SI = cast<SwitchInst>(I);
2627       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
2628       pushValue(SI.getCondition(), InstID, Vals);
2629       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
2630       for (auto Case : SI.cases()) {
2631         Vals.push_back(VE.getValueID(Case.getCaseValue()));
2632         Vals.push_back(VE.getValueID(Case.getCaseSuccessor()));
2633       }
2634     }
2635     break;
2636   case Instruction::IndirectBr:
2637     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
2638     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2639     // Encode the address operand as relative, but not the basic blocks.
2640     pushValue(I.getOperand(0), InstID, Vals);
2641     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
2642       Vals.push_back(VE.getValueID(I.getOperand(i)));
2643     break;
2644 
2645   case Instruction::Invoke: {
2646     const InvokeInst *II = cast<InvokeInst>(&I);
2647     const Value *Callee = II->getCalledValue();
2648     FunctionType *FTy = II->getFunctionType();
2649 
2650     if (II->hasOperandBundles())
2651       writeOperandBundles(II, InstID);
2652 
2653     Code = bitc::FUNC_CODE_INST_INVOKE;
2654 
2655     Vals.push_back(VE.getAttributeListID(II->getAttributes()));
2656     Vals.push_back(II->getCallingConv() | 1 << 13);
2657     Vals.push_back(VE.getValueID(II->getNormalDest()));
2658     Vals.push_back(VE.getValueID(II->getUnwindDest()));
2659     Vals.push_back(VE.getTypeID(FTy));
2660     pushValueAndType(Callee, InstID, Vals);
2661 
2662     // Emit value #'s for the fixed parameters.
2663     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
2664       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
2665 
2666     // Emit type/value pairs for varargs params.
2667     if (FTy->isVarArg()) {
2668       for (unsigned i = FTy->getNumParams(), e = II->getNumArgOperands();
2669            i != e; ++i)
2670         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
2671     }
2672     break;
2673   }
2674   case Instruction::Resume:
2675     Code = bitc::FUNC_CODE_INST_RESUME;
2676     pushValueAndType(I.getOperand(0), InstID, Vals);
2677     break;
2678   case Instruction::CleanupRet: {
2679     Code = bitc::FUNC_CODE_INST_CLEANUPRET;
2680     const auto &CRI = cast<CleanupReturnInst>(I);
2681     pushValue(CRI.getCleanupPad(), InstID, Vals);
2682     if (CRI.hasUnwindDest())
2683       Vals.push_back(VE.getValueID(CRI.getUnwindDest()));
2684     break;
2685   }
2686   case Instruction::CatchRet: {
2687     Code = bitc::FUNC_CODE_INST_CATCHRET;
2688     const auto &CRI = cast<CatchReturnInst>(I);
2689     pushValue(CRI.getCatchPad(), InstID, Vals);
2690     Vals.push_back(VE.getValueID(CRI.getSuccessor()));
2691     break;
2692   }
2693   case Instruction::CleanupPad:
2694   case Instruction::CatchPad: {
2695     const auto &FuncletPad = cast<FuncletPadInst>(I);
2696     Code = isa<CatchPadInst>(FuncletPad) ? bitc::FUNC_CODE_INST_CATCHPAD
2697                                          : bitc::FUNC_CODE_INST_CLEANUPPAD;
2698     pushValue(FuncletPad.getParentPad(), InstID, Vals);
2699 
2700     unsigned NumArgOperands = FuncletPad.getNumArgOperands();
2701     Vals.push_back(NumArgOperands);
2702     for (unsigned Op = 0; Op != NumArgOperands; ++Op)
2703       pushValueAndType(FuncletPad.getArgOperand(Op), InstID, Vals);
2704     break;
2705   }
2706   case Instruction::CatchSwitch: {
2707     Code = bitc::FUNC_CODE_INST_CATCHSWITCH;
2708     const auto &CatchSwitch = cast<CatchSwitchInst>(I);
2709 
2710     pushValue(CatchSwitch.getParentPad(), InstID, Vals);
2711 
2712     unsigned NumHandlers = CatchSwitch.getNumHandlers();
2713     Vals.push_back(NumHandlers);
2714     for (const BasicBlock *CatchPadBB : CatchSwitch.handlers())
2715       Vals.push_back(VE.getValueID(CatchPadBB));
2716 
2717     if (CatchSwitch.hasUnwindDest())
2718       Vals.push_back(VE.getValueID(CatchSwitch.getUnwindDest()));
2719     break;
2720   }
2721   case Instruction::Unreachable:
2722     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
2723     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
2724     break;
2725 
2726   case Instruction::PHI: {
2727     const PHINode &PN = cast<PHINode>(I);
2728     Code = bitc::FUNC_CODE_INST_PHI;
2729     // With the newer instruction encoding, forward references could give
2730     // negative valued IDs.  This is most common for PHIs, so we use
2731     // signed VBRs.
2732     SmallVector<uint64_t, 128> Vals64;
2733     Vals64.push_back(VE.getTypeID(PN.getType()));
2734     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
2735       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64);
2736       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
2737     }
2738     // Emit a Vals64 vector and exit.
2739     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
2740     Vals64.clear();
2741     return;
2742   }
2743 
2744   case Instruction::LandingPad: {
2745     const LandingPadInst &LP = cast<LandingPadInst>(I);
2746     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
2747     Vals.push_back(VE.getTypeID(LP.getType()));
2748     Vals.push_back(LP.isCleanup());
2749     Vals.push_back(LP.getNumClauses());
2750     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
2751       if (LP.isCatch(I))
2752         Vals.push_back(LandingPadInst::Catch);
2753       else
2754         Vals.push_back(LandingPadInst::Filter);
2755       pushValueAndType(LP.getClause(I), InstID, Vals);
2756     }
2757     break;
2758   }
2759 
2760   case Instruction::Alloca: {
2761     Code = bitc::FUNC_CODE_INST_ALLOCA;
2762     const AllocaInst &AI = cast<AllocaInst>(I);
2763     Vals.push_back(VE.getTypeID(AI.getAllocatedType()));
2764     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2765     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
2766     unsigned AlignRecord = Log2_32(AI.getAlignment()) + 1;
2767     assert(Log2_32(Value::MaximumAlignment) + 1 < 1 << 5 &&
2768            "not enough bits for maximum alignment");
2769     assert(AlignRecord < 1 << 5 && "alignment greater than 1 << 64");
2770     AlignRecord |= AI.isUsedWithInAlloca() << 5;
2771     AlignRecord |= 1 << 6;
2772     AlignRecord |= AI.isSwiftError() << 7;
2773     Vals.push_back(AlignRecord);
2774     break;
2775   }
2776 
2777   case Instruction::Load:
2778     if (cast<LoadInst>(I).isAtomic()) {
2779       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
2780       pushValueAndType(I.getOperand(0), InstID, Vals);
2781     } else {
2782       Code = bitc::FUNC_CODE_INST_LOAD;
2783       if (!pushValueAndType(I.getOperand(0), InstID, Vals)) // ptr
2784         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
2785     }
2786     Vals.push_back(VE.getTypeID(I.getType()));
2787     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
2788     Vals.push_back(cast<LoadInst>(I).isVolatile());
2789     if (cast<LoadInst>(I).isAtomic()) {
2790       Vals.push_back(getEncodedOrdering(cast<LoadInst>(I).getOrdering()));
2791       Vals.push_back(getEncodedSyncScopeID(cast<LoadInst>(I).getSyncScopeID()));
2792     }
2793     break;
2794   case Instruction::Store:
2795     if (cast<StoreInst>(I).isAtomic())
2796       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
2797     else
2798       Code = bitc::FUNC_CODE_INST_STORE;
2799     pushValueAndType(I.getOperand(1), InstID, Vals); // ptrty + ptr
2800     pushValueAndType(I.getOperand(0), InstID, Vals); // valty + val
2801     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
2802     Vals.push_back(cast<StoreInst>(I).isVolatile());
2803     if (cast<StoreInst>(I).isAtomic()) {
2804       Vals.push_back(getEncodedOrdering(cast<StoreInst>(I).getOrdering()));
2805       Vals.push_back(
2806           getEncodedSyncScopeID(cast<StoreInst>(I).getSyncScopeID()));
2807     }
2808     break;
2809   case Instruction::AtomicCmpXchg:
2810     Code = bitc::FUNC_CODE_INST_CMPXCHG;
2811     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
2812     pushValueAndType(I.getOperand(1), InstID, Vals); // cmp.
2813     pushValue(I.getOperand(2), InstID, Vals);        // newval.
2814     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
2815     Vals.push_back(
2816         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
2817     Vals.push_back(
2818         getEncodedSyncScopeID(cast<AtomicCmpXchgInst>(I).getSyncScopeID()));
2819     Vals.push_back(
2820         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
2821     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
2822     break;
2823   case Instruction::AtomicRMW:
2824     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
2825     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
2826     pushValue(I.getOperand(1), InstID, Vals);        // val.
2827     Vals.push_back(
2828         getEncodedRMWOperation(cast<AtomicRMWInst>(I).getOperation()));
2829     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
2830     Vals.push_back(getEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
2831     Vals.push_back(
2832         getEncodedSyncScopeID(cast<AtomicRMWInst>(I).getSyncScopeID()));
2833     break;
2834   case Instruction::Fence:
2835     Code = bitc::FUNC_CODE_INST_FENCE;
2836     Vals.push_back(getEncodedOrdering(cast<FenceInst>(I).getOrdering()));
2837     Vals.push_back(getEncodedSyncScopeID(cast<FenceInst>(I).getSyncScopeID()));
2838     break;
2839   case Instruction::Call: {
2840     const CallInst &CI = cast<CallInst>(I);
2841     FunctionType *FTy = CI.getFunctionType();
2842 
2843     if (CI.hasOperandBundles())
2844       writeOperandBundles(&CI, InstID);
2845 
2846     Code = bitc::FUNC_CODE_INST_CALL;
2847 
2848     Vals.push_back(VE.getAttributeListID(CI.getAttributes()));
2849 
2850     unsigned Flags = getOptimizationFlags(&I);
2851     Vals.push_back(CI.getCallingConv() << bitc::CALL_CCONV |
2852                    unsigned(CI.isTailCall()) << bitc::CALL_TAIL |
2853                    unsigned(CI.isMustTailCall()) << bitc::CALL_MUSTTAIL |
2854                    1 << bitc::CALL_EXPLICIT_TYPE |
2855                    unsigned(CI.isNoTailCall()) << bitc::CALL_NOTAIL |
2856                    unsigned(Flags != 0) << bitc::CALL_FMF);
2857     if (Flags != 0)
2858       Vals.push_back(Flags);
2859 
2860     Vals.push_back(VE.getTypeID(FTy));
2861     pushValueAndType(CI.getCalledValue(), InstID, Vals); // Callee
2862 
2863     // Emit value #'s for the fixed parameters.
2864     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
2865       // Check for labels (can happen with asm labels).
2866       if (FTy->getParamType(i)->isLabelTy())
2867         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
2868       else
2869         pushValue(CI.getArgOperand(i), InstID, Vals); // fixed param.
2870     }
2871 
2872     // Emit type/value pairs for varargs params.
2873     if (FTy->isVarArg()) {
2874       for (unsigned i = FTy->getNumParams(), e = CI.getNumArgOperands();
2875            i != e; ++i)
2876         pushValueAndType(CI.getArgOperand(i), InstID, Vals); // varargs
2877     }
2878     break;
2879   }
2880   case Instruction::VAArg:
2881     Code = bitc::FUNC_CODE_INST_VAARG;
2882     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
2883     pushValue(I.getOperand(0), InstID, Vals);                   // valist.
2884     Vals.push_back(VE.getTypeID(I.getType())); // restype.
2885     break;
2886   }
2887 
2888   Stream.EmitRecord(Code, Vals, AbbrevToUse);
2889   Vals.clear();
2890 }
2891 
2892 /// Write a GlobalValue VST to the module. The purpose of this data structure is
2893 /// to allow clients to efficiently find the function body.
2894 void ModuleBitcodeWriter::writeGlobalValueSymbolTable(
2895   DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
2896   // Get the offset of the VST we are writing, and backpatch it into
2897   // the VST forward declaration record.
2898   uint64_t VSTOffset = Stream.GetCurrentBitNo();
2899   // The BitcodeStartBit was the stream offset of the identification block.
2900   VSTOffset -= bitcodeStartBit();
2901   assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
2902   // Note that we add 1 here because the offset is relative to one word
2903   // before the start of the identification block, which was historically
2904   // always the start of the regular bitcode header.
2905   Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32 + 1);
2906 
2907   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
2908 
2909   auto Abbv = std::make_shared<BitCodeAbbrev>();
2910   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
2911   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
2912   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
2913   unsigned FnEntryAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2914 
2915   for (const Function &F : M) {
2916     uint64_t Record[2];
2917 
2918     if (F.isDeclaration())
2919       continue;
2920 
2921     Record[0] = VE.getValueID(&F);
2922 
2923     // Save the word offset of the function (from the start of the
2924     // actual bitcode written to the stream).
2925     uint64_t BitcodeIndex = FunctionToBitcodeIndex[&F] - bitcodeStartBit();
2926     assert((BitcodeIndex & 31) == 0 && "function block not 32-bit aligned");
2927     // Note that we add 1 here because the offset is relative to one word
2928     // before the start of the identification block, which was historically
2929     // always the start of the regular bitcode header.
2930     Record[1] = BitcodeIndex / 32 + 1;
2931 
2932     Stream.EmitRecord(bitc::VST_CODE_FNENTRY, Record, FnEntryAbbrev);
2933   }
2934 
2935   Stream.ExitBlock();
2936 }
2937 
2938 /// Emit names for arguments, instructions and basic blocks in a function.
2939 void ModuleBitcodeWriter::writeFunctionLevelValueSymbolTable(
2940     const ValueSymbolTable &VST) {
2941   if (VST.empty())
2942     return;
2943 
2944   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
2945 
2946   // FIXME: Set up the abbrev, we know how many values there are!
2947   // FIXME: We know if the type names can use 7-bit ascii.
2948   SmallVector<uint64_t, 64> NameVals;
2949 
2950   for (const ValueName &Name : VST) {
2951     // Figure out the encoding to use for the name.
2952     StringEncoding Bits = getStringEncoding(Name.getKey());
2953 
2954     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
2955     NameVals.push_back(VE.getValueID(Name.getValue()));
2956 
2957     // VST_CODE_ENTRY:   [valueid, namechar x N]
2958     // VST_CODE_BBENTRY: [bbid, namechar x N]
2959     unsigned Code;
2960     if (isa<BasicBlock>(Name.getValue())) {
2961       Code = bitc::VST_CODE_BBENTRY;
2962       if (Bits == SE_Char6)
2963         AbbrevToUse = VST_BBENTRY_6_ABBREV;
2964     } else {
2965       Code = bitc::VST_CODE_ENTRY;
2966       if (Bits == SE_Char6)
2967         AbbrevToUse = VST_ENTRY_6_ABBREV;
2968       else if (Bits == SE_Fixed7)
2969         AbbrevToUse = VST_ENTRY_7_ABBREV;
2970     }
2971 
2972     for (const auto P : Name.getKey())
2973       NameVals.push_back((unsigned char)P);
2974 
2975     // Emit the finished record.
2976     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
2977     NameVals.clear();
2978   }
2979 
2980   Stream.ExitBlock();
2981 }
2982 
2983 void ModuleBitcodeWriter::writeUseList(UseListOrder &&Order) {
2984   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
2985   unsigned Code;
2986   if (isa<BasicBlock>(Order.V))
2987     Code = bitc::USELIST_CODE_BB;
2988   else
2989     Code = bitc::USELIST_CODE_DEFAULT;
2990 
2991   SmallVector<uint64_t, 64> Record(Order.Shuffle.begin(), Order.Shuffle.end());
2992   Record.push_back(VE.getValueID(Order.V));
2993   Stream.EmitRecord(Code, Record);
2994 }
2995 
2996 void ModuleBitcodeWriter::writeUseListBlock(const Function *F) {
2997   assert(VE.shouldPreserveUseListOrder() &&
2998          "Expected to be preserving use-list order");
2999 
3000   auto hasMore = [&]() {
3001     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
3002   };
3003   if (!hasMore())
3004     // Nothing to do.
3005     return;
3006 
3007   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
3008   while (hasMore()) {
3009     writeUseList(std::move(VE.UseListOrders.back()));
3010     VE.UseListOrders.pop_back();
3011   }
3012   Stream.ExitBlock();
3013 }
3014 
3015 /// Emit a function body to the module stream.
3016 void ModuleBitcodeWriter::writeFunction(
3017     const Function &F,
3018     DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3019   // Save the bitcode index of the start of this function block for recording
3020   // in the VST.
3021   FunctionToBitcodeIndex[&F] = Stream.GetCurrentBitNo();
3022 
3023   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
3024   VE.incorporateFunction(F);
3025 
3026   SmallVector<unsigned, 64> Vals;
3027 
3028   // Emit the number of basic blocks, so the reader can create them ahead of
3029   // time.
3030   Vals.push_back(VE.getBasicBlocks().size());
3031   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
3032   Vals.clear();
3033 
3034   // If there are function-local constants, emit them now.
3035   unsigned CstStart, CstEnd;
3036   VE.getFunctionConstantRange(CstStart, CstEnd);
3037   writeConstants(CstStart, CstEnd, false);
3038 
3039   // If there is function-local metadata, emit it now.
3040   writeFunctionMetadata(F);
3041 
3042   // Keep a running idea of what the instruction ID is.
3043   unsigned InstID = CstEnd;
3044 
3045   bool NeedsMetadataAttachment = F.hasMetadata();
3046 
3047   DILocation *LastDL = nullptr;
3048   // Finally, emit all the instructions, in order.
3049   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
3050     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
3051          I != E; ++I) {
3052       writeInstruction(*I, InstID, Vals);
3053 
3054       if (!I->getType()->isVoidTy())
3055         ++InstID;
3056 
3057       // If the instruction has metadata, write a metadata attachment later.
3058       NeedsMetadataAttachment |= I->hasMetadataOtherThanDebugLoc();
3059 
3060       // If the instruction has a debug location, emit it.
3061       DILocation *DL = I->getDebugLoc();
3062       if (!DL)
3063         continue;
3064 
3065       if (DL == LastDL) {
3066         // Just repeat the same debug loc as last time.
3067         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
3068         continue;
3069       }
3070 
3071       Vals.push_back(DL->getLine());
3072       Vals.push_back(DL->getColumn());
3073       Vals.push_back(VE.getMetadataOrNullID(DL->getScope()));
3074       Vals.push_back(VE.getMetadataOrNullID(DL->getInlinedAt()));
3075       Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
3076       Vals.clear();
3077 
3078       LastDL = DL;
3079     }
3080 
3081   // Emit names for all the instructions etc.
3082   if (auto *Symtab = F.getValueSymbolTable())
3083     writeFunctionLevelValueSymbolTable(*Symtab);
3084 
3085   if (NeedsMetadataAttachment)
3086     writeFunctionMetadataAttachment(F);
3087   if (VE.shouldPreserveUseListOrder())
3088     writeUseListBlock(&F);
3089   VE.purgeFunction();
3090   Stream.ExitBlock();
3091 }
3092 
3093 // Emit blockinfo, which defines the standard abbreviations etc.
3094 void ModuleBitcodeWriter::writeBlockInfo() {
3095   // We only want to emit block info records for blocks that have multiple
3096   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
3097   // Other blocks can define their abbrevs inline.
3098   Stream.EnterBlockInfoBlock();
3099 
3100   { // 8-bit fixed-width VST_CODE_ENTRY/VST_CODE_BBENTRY strings.
3101     auto Abbv = std::make_shared<BitCodeAbbrev>();
3102     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
3103     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3104     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3105     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3106     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3107         VST_ENTRY_8_ABBREV)
3108       llvm_unreachable("Unexpected abbrev ordering!");
3109   }
3110 
3111   { // 7-bit fixed width VST_CODE_ENTRY strings.
3112     auto Abbv = std::make_shared<BitCodeAbbrev>();
3113     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3114     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3115     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3116     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3117     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3118         VST_ENTRY_7_ABBREV)
3119       llvm_unreachable("Unexpected abbrev ordering!");
3120   }
3121   { // 6-bit char6 VST_CODE_ENTRY strings.
3122     auto Abbv = std::make_shared<BitCodeAbbrev>();
3123     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3124     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3125     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3126     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3127     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3128         VST_ENTRY_6_ABBREV)
3129       llvm_unreachable("Unexpected abbrev ordering!");
3130   }
3131   { // 6-bit char6 VST_CODE_BBENTRY strings.
3132     auto Abbv = std::make_shared<BitCodeAbbrev>();
3133     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
3134     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3135     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3136     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3137     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3138         VST_BBENTRY_6_ABBREV)
3139       llvm_unreachable("Unexpected abbrev ordering!");
3140   }
3141 
3142   { // SETTYPE abbrev for CONSTANTS_BLOCK.
3143     auto Abbv = std::make_shared<BitCodeAbbrev>();
3144     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
3145     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
3146                               VE.computeBitsRequiredForTypeIndicies()));
3147     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3148         CONSTANTS_SETTYPE_ABBREV)
3149       llvm_unreachable("Unexpected abbrev ordering!");
3150   }
3151 
3152   { // INTEGER abbrev for CONSTANTS_BLOCK.
3153     auto Abbv = std::make_shared<BitCodeAbbrev>();
3154     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
3155     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3156     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3157         CONSTANTS_INTEGER_ABBREV)
3158       llvm_unreachable("Unexpected abbrev ordering!");
3159   }
3160 
3161   { // CE_CAST abbrev for CONSTANTS_BLOCK.
3162     auto Abbv = std::make_shared<BitCodeAbbrev>();
3163     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
3164     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
3165     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
3166                               VE.computeBitsRequiredForTypeIndicies()));
3167     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
3168 
3169     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3170         CONSTANTS_CE_CAST_Abbrev)
3171       llvm_unreachable("Unexpected abbrev ordering!");
3172   }
3173   { // NULL abbrev for CONSTANTS_BLOCK.
3174     auto Abbv = std::make_shared<BitCodeAbbrev>();
3175     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
3176     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3177         CONSTANTS_NULL_Abbrev)
3178       llvm_unreachable("Unexpected abbrev ordering!");
3179   }
3180 
3181   // FIXME: This should only use space for first class types!
3182 
3183   { // INST_LOAD abbrev for FUNCTION_BLOCK.
3184     auto Abbv = std::make_shared<BitCodeAbbrev>();
3185     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
3186     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
3187     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
3188                               VE.computeBitsRequiredForTypeIndicies()));
3189     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
3190     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
3191     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3192         FUNCTION_INST_LOAD_ABBREV)
3193       llvm_unreachable("Unexpected abbrev ordering!");
3194   }
3195   { // INST_BINOP abbrev for FUNCTION_BLOCK.
3196     auto Abbv = std::make_shared<BitCodeAbbrev>();
3197     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3198     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3199     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3200     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3201     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3202         FUNCTION_INST_BINOP_ABBREV)
3203       llvm_unreachable("Unexpected abbrev ordering!");
3204   }
3205   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
3206     auto Abbv = std::make_shared<BitCodeAbbrev>();
3207     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3208     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3209     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3210     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3211     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3212     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3213         FUNCTION_INST_BINOP_FLAGS_ABBREV)
3214       llvm_unreachable("Unexpected abbrev ordering!");
3215   }
3216   { // INST_CAST abbrev for FUNCTION_BLOCK.
3217     auto Abbv = std::make_shared<BitCodeAbbrev>();
3218     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
3219     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
3220     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
3221                               VE.computeBitsRequiredForTypeIndicies()));
3222     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
3223     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3224         FUNCTION_INST_CAST_ABBREV)
3225       llvm_unreachable("Unexpected abbrev ordering!");
3226   }
3227 
3228   { // INST_RET abbrev for FUNCTION_BLOCK.
3229     auto Abbv = std::make_shared<BitCodeAbbrev>();
3230     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3231     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3232         FUNCTION_INST_RET_VOID_ABBREV)
3233       llvm_unreachable("Unexpected abbrev ordering!");
3234   }
3235   { // INST_RET abbrev for FUNCTION_BLOCK.
3236     auto Abbv = std::make_shared<BitCodeAbbrev>();
3237     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3238     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
3239     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3240         FUNCTION_INST_RET_VAL_ABBREV)
3241       llvm_unreachable("Unexpected abbrev ordering!");
3242   }
3243   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
3244     auto Abbv = std::make_shared<BitCodeAbbrev>();
3245     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
3246     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3247         FUNCTION_INST_UNREACHABLE_ABBREV)
3248       llvm_unreachable("Unexpected abbrev ordering!");
3249   }
3250   {
3251     auto Abbv = std::make_shared<BitCodeAbbrev>();
3252     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_GEP));
3253     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
3254     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, // dest ty
3255                               Log2_32_Ceil(VE.getTypes().size() + 1)));
3256     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3257     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
3258     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3259         FUNCTION_INST_GEP_ABBREV)
3260       llvm_unreachable("Unexpected abbrev ordering!");
3261   }
3262 
3263   Stream.ExitBlock();
3264 }
3265 
3266 /// Write the module path strings, currently only used when generating
3267 /// a combined index file.
3268 void IndexBitcodeWriter::writeModStrings() {
3269   Stream.EnterSubblock(bitc::MODULE_STRTAB_BLOCK_ID, 3);
3270 
3271   // TODO: See which abbrev sizes we actually need to emit
3272 
3273   // 8-bit fixed-width MST_ENTRY strings.
3274   auto Abbv = std::make_shared<BitCodeAbbrev>();
3275   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3276   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3277   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3278   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3279   unsigned Abbrev8Bit = Stream.EmitAbbrev(std::move(Abbv));
3280 
3281   // 7-bit fixed width MST_ENTRY strings.
3282   Abbv = std::make_shared<BitCodeAbbrev>();
3283   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3284   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3285   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3286   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3287   unsigned Abbrev7Bit = Stream.EmitAbbrev(std::move(Abbv));
3288 
3289   // 6-bit char6 MST_ENTRY strings.
3290   Abbv = std::make_shared<BitCodeAbbrev>();
3291   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3292   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3293   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3294   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3295   unsigned Abbrev6Bit = Stream.EmitAbbrev(std::move(Abbv));
3296 
3297   // Module Hash, 160 bits SHA1. Optionally, emitted after each MST_CODE_ENTRY.
3298   Abbv = std::make_shared<BitCodeAbbrev>();
3299   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_HASH));
3300   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3301   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3302   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3303   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3304   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3305   unsigned AbbrevHash = Stream.EmitAbbrev(std::move(Abbv));
3306 
3307   SmallVector<unsigned, 64> Vals;
3308   forEachModule(
3309       [&](const StringMapEntry<std::pair<uint64_t, ModuleHash>> &MPSE) {
3310         StringRef Key = MPSE.getKey();
3311         const auto &Value = MPSE.getValue();
3312         StringEncoding Bits = getStringEncoding(Key);
3313         unsigned AbbrevToUse = Abbrev8Bit;
3314         if (Bits == SE_Char6)
3315           AbbrevToUse = Abbrev6Bit;
3316         else if (Bits == SE_Fixed7)
3317           AbbrevToUse = Abbrev7Bit;
3318 
3319         Vals.push_back(Value.first);
3320         Vals.append(Key.begin(), Key.end());
3321 
3322         // Emit the finished record.
3323         Stream.EmitRecord(bitc::MST_CODE_ENTRY, Vals, AbbrevToUse);
3324 
3325         // Emit an optional hash for the module now
3326         const auto &Hash = Value.second;
3327         if (llvm::any_of(Hash, [](uint32_t H) { return H; })) {
3328           Vals.assign(Hash.begin(), Hash.end());
3329           // Emit the hash record.
3330           Stream.EmitRecord(bitc::MST_CODE_HASH, Vals, AbbrevHash);
3331         }
3332 
3333         Vals.clear();
3334       });
3335   Stream.ExitBlock();
3336 }
3337 
3338 /// Write the function type metadata related records that need to appear before
3339 /// a function summary entry (whether per-module or combined).
3340 static void writeFunctionTypeMetadataRecords(BitstreamWriter &Stream,
3341                                              FunctionSummary *FS) {
3342   if (!FS->type_tests().empty())
3343     Stream.EmitRecord(bitc::FS_TYPE_TESTS, FS->type_tests());
3344 
3345   SmallVector<uint64_t, 64> Record;
3346 
3347   auto WriteVFuncIdVec = [&](uint64_t Ty,
3348                              ArrayRef<FunctionSummary::VFuncId> VFs) {
3349     if (VFs.empty())
3350       return;
3351     Record.clear();
3352     for (auto &VF : VFs) {
3353       Record.push_back(VF.GUID);
3354       Record.push_back(VF.Offset);
3355     }
3356     Stream.EmitRecord(Ty, Record);
3357   };
3358 
3359   WriteVFuncIdVec(bitc::FS_TYPE_TEST_ASSUME_VCALLS,
3360                   FS->type_test_assume_vcalls());
3361   WriteVFuncIdVec(bitc::FS_TYPE_CHECKED_LOAD_VCALLS,
3362                   FS->type_checked_load_vcalls());
3363 
3364   auto WriteConstVCallVec = [&](uint64_t Ty,
3365                                 ArrayRef<FunctionSummary::ConstVCall> VCs) {
3366     for (auto &VC : VCs) {
3367       Record.clear();
3368       Record.push_back(VC.VFunc.GUID);
3369       Record.push_back(VC.VFunc.Offset);
3370       Record.insert(Record.end(), VC.Args.begin(), VC.Args.end());
3371       Stream.EmitRecord(Ty, Record);
3372     }
3373   };
3374 
3375   WriteConstVCallVec(bitc::FS_TYPE_TEST_ASSUME_CONST_VCALL,
3376                      FS->type_test_assume_const_vcalls());
3377   WriteConstVCallVec(bitc::FS_TYPE_CHECKED_LOAD_CONST_VCALL,
3378                      FS->type_checked_load_const_vcalls());
3379 }
3380 
3381 static void writeWholeProgramDevirtResolutionByArg(
3382     SmallVector<uint64_t, 64> &NameVals, const std::vector<uint64_t> &args,
3383     const WholeProgramDevirtResolution::ByArg &ByArg) {
3384   NameVals.push_back(args.size());
3385   NameVals.insert(NameVals.end(), args.begin(), args.end());
3386 
3387   NameVals.push_back(ByArg.TheKind);
3388   NameVals.push_back(ByArg.Info);
3389   NameVals.push_back(ByArg.Byte);
3390   NameVals.push_back(ByArg.Bit);
3391 }
3392 
3393 static void writeWholeProgramDevirtResolution(
3394     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3395     uint64_t Id, const WholeProgramDevirtResolution &Wpd) {
3396   NameVals.push_back(Id);
3397 
3398   NameVals.push_back(Wpd.TheKind);
3399   NameVals.push_back(StrtabBuilder.add(Wpd.SingleImplName));
3400   NameVals.push_back(Wpd.SingleImplName.size());
3401 
3402   NameVals.push_back(Wpd.ResByArg.size());
3403   for (auto &A : Wpd.ResByArg)
3404     writeWholeProgramDevirtResolutionByArg(NameVals, A.first, A.second);
3405 }
3406 
3407 static void writeTypeIdSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
3408                                      StringTableBuilder &StrtabBuilder,
3409                                      const std::string &Id,
3410                                      const TypeIdSummary &Summary) {
3411   NameVals.push_back(StrtabBuilder.add(Id));
3412   NameVals.push_back(Id.size());
3413 
3414   NameVals.push_back(Summary.TTRes.TheKind);
3415   NameVals.push_back(Summary.TTRes.SizeM1BitWidth);
3416   NameVals.push_back(Summary.TTRes.AlignLog2);
3417   NameVals.push_back(Summary.TTRes.SizeM1);
3418   NameVals.push_back(Summary.TTRes.BitMask);
3419   NameVals.push_back(Summary.TTRes.InlineBits);
3420 
3421   for (auto &W : Summary.WPDRes)
3422     writeWholeProgramDevirtResolution(NameVals, StrtabBuilder, W.first,
3423                                       W.second);
3424 }
3425 
3426 // Helper to emit a single function summary record.
3427 void ModuleBitcodeWriterBase::writePerModuleFunctionSummaryRecord(
3428     SmallVector<uint64_t, 64> &NameVals, GlobalValueSummary *Summary,
3429     unsigned ValueID, unsigned FSCallsAbbrev, unsigned FSCallsProfileAbbrev,
3430     const Function &F) {
3431   NameVals.push_back(ValueID);
3432 
3433   FunctionSummary *FS = cast<FunctionSummary>(Summary);
3434   writeFunctionTypeMetadataRecords(Stream, FS);
3435 
3436   NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
3437   NameVals.push_back(FS->instCount());
3438   NameVals.push_back(getEncodedFFlags(FS->fflags()));
3439   NameVals.push_back(FS->refs().size());
3440 
3441   for (auto &RI : FS->refs())
3442     NameVals.push_back(VE.getValueID(RI.getValue()));
3443 
3444   bool HasProfileData =
3445       F.hasProfileData() || ForceSummaryEdgesCold != FunctionSummary::FSHT_None;
3446   for (auto &ECI : FS->calls()) {
3447     NameVals.push_back(getValueId(ECI.first));
3448     if (HasProfileData)
3449       NameVals.push_back(static_cast<uint8_t>(ECI.second.Hotness));
3450     else if (WriteRelBFToSummary)
3451       NameVals.push_back(ECI.second.RelBlockFreq);
3452   }
3453 
3454   unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
3455   unsigned Code =
3456       (HasProfileData ? bitc::FS_PERMODULE_PROFILE
3457                       : (WriteRelBFToSummary ? bitc::FS_PERMODULE_RELBF
3458                                              : bitc::FS_PERMODULE));
3459 
3460   // Emit the finished record.
3461   Stream.EmitRecord(Code, NameVals, FSAbbrev);
3462   NameVals.clear();
3463 }
3464 
3465 // Collect the global value references in the given variable's initializer,
3466 // and emit them in a summary record.
3467 void ModuleBitcodeWriterBase::writeModuleLevelReferences(
3468     const GlobalVariable &V, SmallVector<uint64_t, 64> &NameVals,
3469     unsigned FSModRefsAbbrev) {
3470   auto VI = Index->getValueInfo(GlobalValue::getGUID(V.getName()));
3471   if (!VI || VI.getSummaryList().empty()) {
3472     // Only declarations should not have a summary (a declaration might however
3473     // have a summary if the def was in module level asm).
3474     assert(V.isDeclaration());
3475     return;
3476   }
3477   auto *Summary = VI.getSummaryList()[0].get();
3478   NameVals.push_back(VE.getValueID(&V));
3479   GlobalVarSummary *VS = cast<GlobalVarSummary>(Summary);
3480   NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
3481 
3482   unsigned SizeBeforeRefs = NameVals.size();
3483   for (auto &RI : VS->refs())
3484     NameVals.push_back(VE.getValueID(RI.getValue()));
3485   // Sort the refs for determinism output, the vector returned by FS->refs() has
3486   // been initialized from a DenseSet.
3487   llvm::sort(NameVals.begin() + SizeBeforeRefs, NameVals.end());
3488 
3489   Stream.EmitRecord(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS, NameVals,
3490                     FSModRefsAbbrev);
3491   NameVals.clear();
3492 }
3493 
3494 // Current version for the summary.
3495 // This is bumped whenever we introduce changes in the way some record are
3496 // interpreted, like flags for instance.
3497 static const uint64_t INDEX_VERSION = 4;
3498 
3499 /// Emit the per-module summary section alongside the rest of
3500 /// the module's bitcode.
3501 void ModuleBitcodeWriterBase::writePerModuleGlobalValueSummary() {
3502   // By default we compile with ThinLTO if the module has a summary, but the
3503   // client can request full LTO with a module flag.
3504   bool IsThinLTO = true;
3505   if (auto *MD =
3506           mdconst::extract_or_null<ConstantInt>(M.getModuleFlag("ThinLTO")))
3507     IsThinLTO = MD->getZExtValue();
3508   Stream.EnterSubblock(IsThinLTO ? bitc::GLOBALVAL_SUMMARY_BLOCK_ID
3509                                  : bitc::FULL_LTO_GLOBALVAL_SUMMARY_BLOCK_ID,
3510                        4);
3511 
3512   Stream.EmitRecord(bitc::FS_VERSION, ArrayRef<uint64_t>{INDEX_VERSION});
3513 
3514   if (Index->begin() == Index->end()) {
3515     Stream.ExitBlock();
3516     return;
3517   }
3518 
3519   for (const auto &GVI : valueIds()) {
3520     Stream.EmitRecord(bitc::FS_VALUE_GUID,
3521                       ArrayRef<uint64_t>{GVI.second, GVI.first});
3522   }
3523 
3524   // Abbrev for FS_PERMODULE_PROFILE.
3525   auto Abbv = std::make_shared<BitCodeAbbrev>();
3526   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_PROFILE));
3527   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3528   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3529   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3530   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3531   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3532   // numrefs x valueid, n x (valueid, hotness)
3533   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3534   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3535   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3536 
3537   // Abbrev for FS_PERMODULE or FS_PERMODULE_RELBF.
3538   Abbv = std::make_shared<BitCodeAbbrev>();
3539   if (WriteRelBFToSummary)
3540     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_RELBF));
3541   else
3542     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE));
3543   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3544   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3545   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3546   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3547   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3548   // numrefs x valueid, n x (valueid [, rel_block_freq])
3549   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3550   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3551   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3552 
3553   // Abbrev for FS_PERMODULE_GLOBALVAR_INIT_REFS.
3554   Abbv = std::make_shared<BitCodeAbbrev>();
3555   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS));
3556   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
3557   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
3558   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));  // valueids
3559   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3560   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3561 
3562   // Abbrev for FS_ALIAS.
3563   Abbv = std::make_shared<BitCodeAbbrev>();
3564   Abbv->Add(BitCodeAbbrevOp(bitc::FS_ALIAS));
3565   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3566   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3567   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3568   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3569 
3570   SmallVector<uint64_t, 64> NameVals;
3571   // Iterate over the list of functions instead of the Index to
3572   // ensure the ordering is stable.
3573   for (const Function &F : M) {
3574     // Summary emission does not support anonymous functions, they have to
3575     // renamed using the anonymous function renaming pass.
3576     if (!F.hasName())
3577       report_fatal_error("Unexpected anonymous function when writing summary");
3578 
3579     ValueInfo VI = Index->getValueInfo(GlobalValue::getGUID(F.getName()));
3580     if (!VI || VI.getSummaryList().empty()) {
3581       // Only declarations should not have a summary (a declaration might
3582       // however have a summary if the def was in module level asm).
3583       assert(F.isDeclaration());
3584       continue;
3585     }
3586     auto *Summary = VI.getSummaryList()[0].get();
3587     writePerModuleFunctionSummaryRecord(NameVals, Summary, VE.getValueID(&F),
3588                                         FSCallsAbbrev, FSCallsProfileAbbrev, F);
3589   }
3590 
3591   // Capture references from GlobalVariable initializers, which are outside
3592   // of a function scope.
3593   for (const GlobalVariable &G : M.globals())
3594     writeModuleLevelReferences(G, NameVals, FSModRefsAbbrev);
3595 
3596   for (const GlobalAlias &A : M.aliases()) {
3597     auto *Aliasee = A.getBaseObject();
3598     if (!Aliasee->hasName())
3599       // Nameless function don't have an entry in the summary, skip it.
3600       continue;
3601     auto AliasId = VE.getValueID(&A);
3602     auto AliaseeId = VE.getValueID(Aliasee);
3603     NameVals.push_back(AliasId);
3604     auto *Summary = Index->getGlobalValueSummary(A);
3605     AliasSummary *AS = cast<AliasSummary>(Summary);
3606     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
3607     NameVals.push_back(AliaseeId);
3608     Stream.EmitRecord(bitc::FS_ALIAS, NameVals, FSAliasAbbrev);
3609     NameVals.clear();
3610   }
3611 
3612   Stream.ExitBlock();
3613 }
3614 
3615 /// Emit the combined summary section into the combined index file.
3616 void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
3617   Stream.EnterSubblock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID, 3);
3618   Stream.EmitRecord(bitc::FS_VERSION, ArrayRef<uint64_t>{INDEX_VERSION});
3619 
3620   // Write the index flags.
3621   uint64_t Flags = 0;
3622   if (Index.withGlobalValueDeadStripping())
3623     Flags |= 0x1;
3624   if (Index.skipModuleByDistributedBackend())
3625     Flags |= 0x2;
3626   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Flags});
3627 
3628   for (const auto &GVI : valueIds()) {
3629     Stream.EmitRecord(bitc::FS_VALUE_GUID,
3630                       ArrayRef<uint64_t>{GVI.second, GVI.first});
3631   }
3632 
3633   // Abbrev for FS_COMBINED.
3634   auto Abbv = std::make_shared<BitCodeAbbrev>();
3635   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED));
3636   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3637   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3638   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3639   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3640   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3641   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3642   // numrefs x valueid, n x (valueid)
3643   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3644   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3645   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3646 
3647   // Abbrev for FS_COMBINED_PROFILE.
3648   Abbv = std::make_shared<BitCodeAbbrev>();
3649   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_PROFILE));
3650   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3651   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3652   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3653   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3654   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3655   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3656   // numrefs x valueid, n x (valueid, hotness)
3657   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3658   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3659   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3660 
3661   // Abbrev for FS_COMBINED_GLOBALVAR_INIT_REFS.
3662   Abbv = std::make_shared<BitCodeAbbrev>();
3663   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS));
3664   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3665   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3666   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3667   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));    // valueids
3668   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3669   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3670 
3671   // Abbrev for FS_COMBINED_ALIAS.
3672   Abbv = std::make_shared<BitCodeAbbrev>();
3673   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_ALIAS));
3674   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3675   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3676   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3677   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3678   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3679 
3680   // The aliases are emitted as a post-pass, and will point to the value
3681   // id of the aliasee. Save them in a vector for post-processing.
3682   SmallVector<AliasSummary *, 64> Aliases;
3683 
3684   // Save the value id for each summary for alias emission.
3685   DenseMap<const GlobalValueSummary *, unsigned> SummaryToValueIdMap;
3686 
3687   SmallVector<uint64_t, 64> NameVals;
3688 
3689   // For local linkage, we also emit the original name separately
3690   // immediately after the record.
3691   auto MaybeEmitOriginalName = [&](GlobalValueSummary &S) {
3692     if (!GlobalValue::isLocalLinkage(S.linkage()))
3693       return;
3694     NameVals.push_back(S.getOriginalName());
3695     Stream.EmitRecord(bitc::FS_COMBINED_ORIGINAL_NAME, NameVals);
3696     NameVals.clear();
3697   };
3698 
3699   forEachSummary([&](GVInfo I, bool IsAliasee) {
3700     GlobalValueSummary *S = I.second;
3701     assert(S);
3702 
3703     auto ValueId = getValueId(I.first);
3704     assert(ValueId);
3705     SummaryToValueIdMap[S] = *ValueId;
3706 
3707     // If this is invoked for an aliasee, we want to record the above
3708     // mapping, but then not emit a summary entry (if the aliasee is
3709     // to be imported, we will invoke this separately with IsAliasee=false).
3710     if (IsAliasee)
3711       return;
3712 
3713     if (auto *AS = dyn_cast<AliasSummary>(S)) {
3714       // Will process aliases as a post-pass because the reader wants all
3715       // global to be loaded first.
3716       Aliases.push_back(AS);
3717       return;
3718     }
3719 
3720     if (auto *VS = dyn_cast<GlobalVarSummary>(S)) {
3721       NameVals.push_back(*ValueId);
3722       NameVals.push_back(Index.getModuleId(VS->modulePath()));
3723       NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
3724       for (auto &RI : VS->refs()) {
3725         auto RefValueId = getValueId(RI.getGUID());
3726         if (!RefValueId)
3727           continue;
3728         NameVals.push_back(*RefValueId);
3729       }
3730 
3731       // Emit the finished record.
3732       Stream.EmitRecord(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS, NameVals,
3733                         FSModRefsAbbrev);
3734       NameVals.clear();
3735       MaybeEmitOriginalName(*S);
3736       return;
3737     }
3738 
3739     auto *FS = cast<FunctionSummary>(S);
3740     writeFunctionTypeMetadataRecords(Stream, FS);
3741 
3742     NameVals.push_back(*ValueId);
3743     NameVals.push_back(Index.getModuleId(FS->modulePath()));
3744     NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
3745     NameVals.push_back(FS->instCount());
3746     NameVals.push_back(getEncodedFFlags(FS->fflags()));
3747     // Fill in below
3748     NameVals.push_back(0);
3749 
3750     unsigned Count = 0;
3751     for (auto &RI : FS->refs()) {
3752       auto RefValueId = getValueId(RI.getGUID());
3753       if (!RefValueId)
3754         continue;
3755       NameVals.push_back(*RefValueId);
3756       Count++;
3757     }
3758     NameVals[5] = Count;
3759 
3760     bool HasProfileData = false;
3761     for (auto &EI : FS->calls()) {
3762       HasProfileData |=
3763           EI.second.getHotness() != CalleeInfo::HotnessType::Unknown;
3764       if (HasProfileData)
3765         break;
3766     }
3767 
3768     for (auto &EI : FS->calls()) {
3769       // If this GUID doesn't have a value id, it doesn't have a function
3770       // summary and we don't need to record any calls to it.
3771       GlobalValue::GUID GUID = EI.first.getGUID();
3772       auto CallValueId = getValueId(GUID);
3773       if (!CallValueId) {
3774         // For SamplePGO, the indirect call targets for local functions will
3775         // have its original name annotated in profile. We try to find the
3776         // corresponding PGOFuncName as the GUID.
3777         GUID = Index.getGUIDFromOriginalID(GUID);
3778         if (GUID == 0)
3779           continue;
3780         CallValueId = getValueId(GUID);
3781         if (!CallValueId)
3782           continue;
3783         // The mapping from OriginalId to GUID may return a GUID
3784         // that corresponds to a static variable. Filter it out here.
3785         // This can happen when
3786         // 1) There is a call to a library function which does not have
3787         // a CallValidId;
3788         // 2) There is a static variable with the  OriginalGUID identical
3789         // to the GUID of the library function in 1);
3790         // When this happens, the logic for SamplePGO kicks in and
3791         // the static variable in 2) will be found, which needs to be
3792         // filtered out.
3793         auto *GVSum = Index.getGlobalValueSummary(GUID, false);
3794         if (GVSum &&
3795             GVSum->getSummaryKind() == GlobalValueSummary::GlobalVarKind)
3796           continue;
3797       }
3798       NameVals.push_back(*CallValueId);
3799       if (HasProfileData)
3800         NameVals.push_back(static_cast<uint8_t>(EI.second.Hotness));
3801     }
3802 
3803     unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
3804     unsigned Code =
3805         (HasProfileData ? bitc::FS_COMBINED_PROFILE : bitc::FS_COMBINED);
3806 
3807     // Emit the finished record.
3808     Stream.EmitRecord(Code, NameVals, FSAbbrev);
3809     NameVals.clear();
3810     MaybeEmitOriginalName(*S);
3811   });
3812 
3813   for (auto *AS : Aliases) {
3814     auto AliasValueId = SummaryToValueIdMap[AS];
3815     assert(AliasValueId);
3816     NameVals.push_back(AliasValueId);
3817     NameVals.push_back(Index.getModuleId(AS->modulePath()));
3818     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
3819     auto AliaseeValueId = SummaryToValueIdMap[&AS->getAliasee()];
3820     assert(AliaseeValueId);
3821     NameVals.push_back(AliaseeValueId);
3822 
3823     // Emit the finished record.
3824     Stream.EmitRecord(bitc::FS_COMBINED_ALIAS, NameVals, FSAliasAbbrev);
3825     NameVals.clear();
3826     MaybeEmitOriginalName(*AS);
3827   }
3828 
3829   if (!Index.cfiFunctionDefs().empty()) {
3830     for (auto &S : Index.cfiFunctionDefs()) {
3831       NameVals.push_back(StrtabBuilder.add(S));
3832       NameVals.push_back(S.size());
3833     }
3834     Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DEFS, NameVals);
3835     NameVals.clear();
3836   }
3837 
3838   if (!Index.cfiFunctionDecls().empty()) {
3839     for (auto &S : Index.cfiFunctionDecls()) {
3840       NameVals.push_back(StrtabBuilder.add(S));
3841       NameVals.push_back(S.size());
3842     }
3843     Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DECLS, NameVals);
3844     NameVals.clear();
3845   }
3846 
3847   if (!Index.typeIds().empty()) {
3848     for (auto &S : Index.typeIds()) {
3849       writeTypeIdSummaryRecord(NameVals, StrtabBuilder, S.first, S.second);
3850       Stream.EmitRecord(bitc::FS_TYPE_ID, NameVals);
3851       NameVals.clear();
3852     }
3853   }
3854 
3855   Stream.ExitBlock();
3856 }
3857 
3858 /// Create the "IDENTIFICATION_BLOCK_ID" containing a single string with the
3859 /// current llvm version, and a record for the epoch number.
3860 static void writeIdentificationBlock(BitstreamWriter &Stream) {
3861   Stream.EnterSubblock(bitc::IDENTIFICATION_BLOCK_ID, 5);
3862 
3863   // Write the "user readable" string identifying the bitcode producer
3864   auto Abbv = std::make_shared<BitCodeAbbrev>();
3865   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_STRING));
3866   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3867   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3868   auto StringAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3869   writeStringRecord(Stream, bitc::IDENTIFICATION_CODE_STRING,
3870                     "LLVM" LLVM_VERSION_STRING, StringAbbrev);
3871 
3872   // Write the epoch version
3873   Abbv = std::make_shared<BitCodeAbbrev>();
3874   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_EPOCH));
3875   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
3876   auto EpochAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3877   SmallVector<unsigned, 1> Vals = {bitc::BITCODE_CURRENT_EPOCH};
3878   Stream.EmitRecord(bitc::IDENTIFICATION_CODE_EPOCH, Vals, EpochAbbrev);
3879   Stream.ExitBlock();
3880 }
3881 
3882 void ModuleBitcodeWriter::writeModuleHash(size_t BlockStartPos) {
3883   // Emit the module's hash.
3884   // MODULE_CODE_HASH: [5*i32]
3885   if (GenerateHash) {
3886     uint32_t Vals[5];
3887     Hasher.update(ArrayRef<uint8_t>((const uint8_t *)&(Buffer)[BlockStartPos],
3888                                     Buffer.size() - BlockStartPos));
3889     StringRef Hash = Hasher.result();
3890     for (int Pos = 0; Pos < 20; Pos += 4) {
3891       Vals[Pos / 4] = support::endian::read32be(Hash.data() + Pos);
3892     }
3893 
3894     // Emit the finished record.
3895     Stream.EmitRecord(bitc::MODULE_CODE_HASH, Vals);
3896 
3897     if (ModHash)
3898       // Save the written hash value.
3899       std::copy(std::begin(Vals), std::end(Vals), std::begin(*ModHash));
3900   }
3901 }
3902 
3903 void ModuleBitcodeWriter::write() {
3904   writeIdentificationBlock(Stream);
3905 
3906   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
3907   size_t BlockStartPos = Buffer.size();
3908 
3909   writeModuleVersion();
3910 
3911   // Emit blockinfo, which defines the standard abbreviations etc.
3912   writeBlockInfo();
3913 
3914   // Emit information about attribute groups.
3915   writeAttributeGroupTable();
3916 
3917   // Emit information about parameter attributes.
3918   writeAttributeTable();
3919 
3920   // Emit information describing all of the types in the module.
3921   writeTypeTable();
3922 
3923   writeComdats();
3924 
3925   // Emit top-level description of module, including target triple, inline asm,
3926   // descriptors for global variables, and function prototype info.
3927   writeModuleInfo();
3928 
3929   // Emit constants.
3930   writeModuleConstants();
3931 
3932   // Emit metadata kind names.
3933   writeModuleMetadataKinds();
3934 
3935   // Emit metadata.
3936   writeModuleMetadata();
3937 
3938   // Emit module-level use-lists.
3939   if (VE.shouldPreserveUseListOrder())
3940     writeUseListBlock(nullptr);
3941 
3942   writeOperandBundleTags();
3943   writeSyncScopeNames();
3944 
3945   // Emit function bodies.
3946   DenseMap<const Function *, uint64_t> FunctionToBitcodeIndex;
3947   for (Module::const_iterator F = M.begin(), E = M.end(); F != E; ++F)
3948     if (!F->isDeclaration())
3949       writeFunction(*F, FunctionToBitcodeIndex);
3950 
3951   // Need to write after the above call to WriteFunction which populates
3952   // the summary information in the index.
3953   if (Index)
3954     writePerModuleGlobalValueSummary();
3955 
3956   writeGlobalValueSymbolTable(FunctionToBitcodeIndex);
3957 
3958   writeModuleHash(BlockStartPos);
3959 
3960   Stream.ExitBlock();
3961 }
3962 
3963 static void writeInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
3964                                uint32_t &Position) {
3965   support::endian::write32le(&Buffer[Position], Value);
3966   Position += 4;
3967 }
3968 
3969 /// If generating a bc file on darwin, we have to emit a
3970 /// header and trailer to make it compatible with the system archiver.  To do
3971 /// this we emit the following header, and then emit a trailer that pads the
3972 /// file out to be a multiple of 16 bytes.
3973 ///
3974 /// struct bc_header {
3975 ///   uint32_t Magic;         // 0x0B17C0DE
3976 ///   uint32_t Version;       // Version, currently always 0.
3977 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
3978 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
3979 ///   uint32_t CPUType;       // CPU specifier.
3980 ///   ... potentially more later ...
3981 /// };
3982 static void emitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
3983                                          const Triple &TT) {
3984   unsigned CPUType = ~0U;
3985 
3986   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
3987   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
3988   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
3989   // specific constants here because they are implicitly part of the Darwin ABI.
3990   enum {
3991     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
3992     DARWIN_CPU_TYPE_X86        = 7,
3993     DARWIN_CPU_TYPE_ARM        = 12,
3994     DARWIN_CPU_TYPE_POWERPC    = 18
3995   };
3996 
3997   Triple::ArchType Arch = TT.getArch();
3998   if (Arch == Triple::x86_64)
3999     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
4000   else if (Arch == Triple::x86)
4001     CPUType = DARWIN_CPU_TYPE_X86;
4002   else if (Arch == Triple::ppc)
4003     CPUType = DARWIN_CPU_TYPE_POWERPC;
4004   else if (Arch == Triple::ppc64)
4005     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
4006   else if (Arch == Triple::arm || Arch == Triple::thumb)
4007     CPUType = DARWIN_CPU_TYPE_ARM;
4008 
4009   // Traditional Bitcode starts after header.
4010   assert(Buffer.size() >= BWH_HeaderSize &&
4011          "Expected header size to be reserved");
4012   unsigned BCOffset = BWH_HeaderSize;
4013   unsigned BCSize = Buffer.size() - BWH_HeaderSize;
4014 
4015   // Write the magic and version.
4016   unsigned Position = 0;
4017   writeInt32ToBuffer(0x0B17C0DE, Buffer, Position);
4018   writeInt32ToBuffer(0, Buffer, Position); // Version.
4019   writeInt32ToBuffer(BCOffset, Buffer, Position);
4020   writeInt32ToBuffer(BCSize, Buffer, Position);
4021   writeInt32ToBuffer(CPUType, Buffer, Position);
4022 
4023   // If the file is not a multiple of 16 bytes, insert dummy padding.
4024   while (Buffer.size() & 15)
4025     Buffer.push_back(0);
4026 }
4027 
4028 /// Helper to write the header common to all bitcode files.
4029 static void writeBitcodeHeader(BitstreamWriter &Stream) {
4030   // Emit the file header.
4031   Stream.Emit((unsigned)'B', 8);
4032   Stream.Emit((unsigned)'C', 8);
4033   Stream.Emit(0x0, 4);
4034   Stream.Emit(0xC, 4);
4035   Stream.Emit(0xE, 4);
4036   Stream.Emit(0xD, 4);
4037 }
4038 
4039 BitcodeWriter::BitcodeWriter(SmallVectorImpl<char> &Buffer)
4040     : Buffer(Buffer), Stream(new BitstreamWriter(Buffer)) {
4041   writeBitcodeHeader(*Stream);
4042 }
4043 
4044 BitcodeWriter::~BitcodeWriter() { assert(WroteStrtab); }
4045 
4046 void BitcodeWriter::writeBlob(unsigned Block, unsigned Record, StringRef Blob) {
4047   Stream->EnterSubblock(Block, 3);
4048 
4049   auto Abbv = std::make_shared<BitCodeAbbrev>();
4050   Abbv->Add(BitCodeAbbrevOp(Record));
4051   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
4052   auto AbbrevNo = Stream->EmitAbbrev(std::move(Abbv));
4053 
4054   Stream->EmitRecordWithBlob(AbbrevNo, ArrayRef<uint64_t>{Record}, Blob);
4055 
4056   Stream->ExitBlock();
4057 }
4058 
4059 void BitcodeWriter::writeSymtab() {
4060   assert(!WroteStrtab && !WroteSymtab);
4061 
4062   // If any module has module-level inline asm, we will require a registered asm
4063   // parser for the target so that we can create an accurate symbol table for
4064   // the module.
4065   for (Module *M : Mods) {
4066     if (M->getModuleInlineAsm().empty())
4067       continue;
4068 
4069     std::string Err;
4070     const Triple TT(M->getTargetTriple());
4071     const Target *T = TargetRegistry::lookupTarget(TT.str(), Err);
4072     if (!T || !T->hasMCAsmParser())
4073       return;
4074   }
4075 
4076   WroteSymtab = true;
4077   SmallVector<char, 0> Symtab;
4078   // The irsymtab::build function may be unable to create a symbol table if the
4079   // module is malformed (e.g. it contains an invalid alias). Writing a symbol
4080   // table is not required for correctness, but we still want to be able to
4081   // write malformed modules to bitcode files, so swallow the error.
4082   if (Error E = irsymtab::build(Mods, Symtab, StrtabBuilder, Alloc)) {
4083     consumeError(std::move(E));
4084     return;
4085   }
4086 
4087   writeBlob(bitc::SYMTAB_BLOCK_ID, bitc::SYMTAB_BLOB,
4088             {Symtab.data(), Symtab.size()});
4089 }
4090 
4091 void BitcodeWriter::writeStrtab() {
4092   assert(!WroteStrtab);
4093 
4094   std::vector<char> Strtab;
4095   StrtabBuilder.finalizeInOrder();
4096   Strtab.resize(StrtabBuilder.getSize());
4097   StrtabBuilder.write((uint8_t *)Strtab.data());
4098 
4099   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB,
4100             {Strtab.data(), Strtab.size()});
4101 
4102   WroteStrtab = true;
4103 }
4104 
4105 void BitcodeWriter::copyStrtab(StringRef Strtab) {
4106   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB, Strtab);
4107   WroteStrtab = true;
4108 }
4109 
4110 void BitcodeWriter::writeModule(const Module &M,
4111                                 bool ShouldPreserveUseListOrder,
4112                                 const ModuleSummaryIndex *Index,
4113                                 bool GenerateHash, ModuleHash *ModHash) {
4114   assert(!WroteStrtab);
4115 
4116   // The Mods vector is used by irsymtab::build, which requires non-const
4117   // Modules in case it needs to materialize metadata. But the bitcode writer
4118   // requires that the module is materialized, so we can cast to non-const here,
4119   // after checking that it is in fact materialized.
4120   assert(M.isMaterialized());
4121   Mods.push_back(const_cast<Module *>(&M));
4122 
4123   ModuleBitcodeWriter ModuleWriter(M, Buffer, StrtabBuilder, *Stream,
4124                                    ShouldPreserveUseListOrder, Index,
4125                                    GenerateHash, ModHash);
4126   ModuleWriter.write();
4127 }
4128 
4129 void BitcodeWriter::writeIndex(
4130     const ModuleSummaryIndex *Index,
4131     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4132   IndexBitcodeWriter IndexWriter(*Stream, StrtabBuilder, *Index,
4133                                  ModuleToSummariesForIndex);
4134   IndexWriter.write();
4135 }
4136 
4137 /// Write the specified module to the specified output stream.
4138 void llvm::WriteBitcodeToFile(const Module &M, raw_ostream &Out,
4139                               bool ShouldPreserveUseListOrder,
4140                               const ModuleSummaryIndex *Index,
4141                               bool GenerateHash, ModuleHash *ModHash) {
4142   SmallVector<char, 0> Buffer;
4143   Buffer.reserve(256*1024);
4144 
4145   // If this is darwin or another generic macho target, reserve space for the
4146   // header.
4147   Triple TT(M.getTargetTriple());
4148   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4149     Buffer.insert(Buffer.begin(), BWH_HeaderSize, 0);
4150 
4151   BitcodeWriter Writer(Buffer);
4152   Writer.writeModule(M, ShouldPreserveUseListOrder, Index, GenerateHash,
4153                      ModHash);
4154   Writer.writeSymtab();
4155   Writer.writeStrtab();
4156 
4157   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4158     emitDarwinBCHeaderAndTrailer(Buffer, TT);
4159 
4160   // Write the generated bitstream to "Out".
4161   Out.write((char*)&Buffer.front(), Buffer.size());
4162 }
4163 
4164 void IndexBitcodeWriter::write() {
4165   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4166 
4167   writeModuleVersion();
4168 
4169   // Write the module paths in the combined index.
4170   writeModStrings();
4171 
4172   // Write the summary combined index records.
4173   writeCombinedGlobalValueSummary();
4174 
4175   Stream.ExitBlock();
4176 }
4177 
4178 // Write the specified module summary index to the given raw output stream,
4179 // where it will be written in a new bitcode block. This is used when
4180 // writing the combined index file for ThinLTO. When writing a subset of the
4181 // index for a distributed backend, provide a \p ModuleToSummariesForIndex map.
4182 void llvm::WriteIndexToFile(
4183     const ModuleSummaryIndex &Index, raw_ostream &Out,
4184     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4185   SmallVector<char, 0> Buffer;
4186   Buffer.reserve(256 * 1024);
4187 
4188   BitcodeWriter Writer(Buffer);
4189   Writer.writeIndex(&Index, ModuleToSummariesForIndex);
4190   Writer.writeStrtab();
4191 
4192   Out.write((char *)&Buffer.front(), Buffer.size());
4193 }
4194 
4195 namespace {
4196 
4197 /// Class to manage the bitcode writing for a thin link bitcode file.
4198 class ThinLinkBitcodeWriter : public ModuleBitcodeWriterBase {
4199   /// ModHash is for use in ThinLTO incremental build, generated while writing
4200   /// the module bitcode file.
4201   const ModuleHash *ModHash;
4202 
4203 public:
4204   ThinLinkBitcodeWriter(const Module &M, StringTableBuilder &StrtabBuilder,
4205                         BitstreamWriter &Stream,
4206                         const ModuleSummaryIndex &Index,
4207                         const ModuleHash &ModHash)
4208       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
4209                                 /*ShouldPreserveUseListOrder=*/false, &Index),
4210         ModHash(&ModHash) {}
4211 
4212   void write();
4213 
4214 private:
4215   void writeSimplifiedModuleInfo();
4216 };
4217 
4218 } // end anonymous namespace
4219 
4220 // This function writes a simpilified module info for thin link bitcode file.
4221 // It only contains the source file name along with the name(the offset and
4222 // size in strtab) and linkage for global values. For the global value info
4223 // entry, in order to keep linkage at offset 5, there are three zeros used
4224 // as padding.
4225 void ThinLinkBitcodeWriter::writeSimplifiedModuleInfo() {
4226   SmallVector<unsigned, 64> Vals;
4227   // Emit the module's source file name.
4228   {
4229     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
4230     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
4231     if (Bits == SE_Char6)
4232       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
4233     else if (Bits == SE_Fixed7)
4234       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
4235 
4236     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
4237     auto Abbv = std::make_shared<BitCodeAbbrev>();
4238     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
4239     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4240     Abbv->Add(AbbrevOpToUse);
4241     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4242 
4243     for (const auto P : M.getSourceFileName())
4244       Vals.push_back((unsigned char)P);
4245 
4246     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
4247     Vals.clear();
4248   }
4249 
4250   // Emit the global variable information.
4251   for (const GlobalVariable &GV : M.globals()) {
4252     // GLOBALVAR: [strtab offset, strtab size, 0, 0, 0, linkage]
4253     Vals.push_back(StrtabBuilder.add(GV.getName()));
4254     Vals.push_back(GV.getName().size());
4255     Vals.push_back(0);
4256     Vals.push_back(0);
4257     Vals.push_back(0);
4258     Vals.push_back(getEncodedLinkage(GV));
4259 
4260     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals);
4261     Vals.clear();
4262   }
4263 
4264   // Emit the function proto information.
4265   for (const Function &F : M) {
4266     // FUNCTION:  [strtab offset, strtab size, 0, 0, 0, linkage]
4267     Vals.push_back(StrtabBuilder.add(F.getName()));
4268     Vals.push_back(F.getName().size());
4269     Vals.push_back(0);
4270     Vals.push_back(0);
4271     Vals.push_back(0);
4272     Vals.push_back(getEncodedLinkage(F));
4273 
4274     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals);
4275     Vals.clear();
4276   }
4277 
4278   // Emit the alias information.
4279   for (const GlobalAlias &A : M.aliases()) {
4280     // ALIAS: [strtab offset, strtab size, 0, 0, 0, linkage]
4281     Vals.push_back(StrtabBuilder.add(A.getName()));
4282     Vals.push_back(A.getName().size());
4283     Vals.push_back(0);
4284     Vals.push_back(0);
4285     Vals.push_back(0);
4286     Vals.push_back(getEncodedLinkage(A));
4287 
4288     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals);
4289     Vals.clear();
4290   }
4291 
4292   // Emit the ifunc information.
4293   for (const GlobalIFunc &I : M.ifuncs()) {
4294     // IFUNC: [strtab offset, strtab size, 0, 0, 0, linkage]
4295     Vals.push_back(StrtabBuilder.add(I.getName()));
4296     Vals.push_back(I.getName().size());
4297     Vals.push_back(0);
4298     Vals.push_back(0);
4299     Vals.push_back(0);
4300     Vals.push_back(getEncodedLinkage(I));
4301 
4302     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
4303     Vals.clear();
4304   }
4305 }
4306 
4307 void ThinLinkBitcodeWriter::write() {
4308   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4309 
4310   writeModuleVersion();
4311 
4312   writeSimplifiedModuleInfo();
4313 
4314   writePerModuleGlobalValueSummary();
4315 
4316   // Write module hash.
4317   Stream.EmitRecord(bitc::MODULE_CODE_HASH, ArrayRef<uint32_t>(*ModHash));
4318 
4319   Stream.ExitBlock();
4320 }
4321 
4322 void BitcodeWriter::writeThinLinkBitcode(const Module &M,
4323                                          const ModuleSummaryIndex &Index,
4324                                          const ModuleHash &ModHash) {
4325   assert(!WroteStrtab);
4326 
4327   // The Mods vector is used by irsymtab::build, which requires non-const
4328   // Modules in case it needs to materialize metadata. But the bitcode writer
4329   // requires that the module is materialized, so we can cast to non-const here,
4330   // after checking that it is in fact materialized.
4331   assert(M.isMaterialized());
4332   Mods.push_back(const_cast<Module *>(&M));
4333 
4334   ThinLinkBitcodeWriter ThinLinkWriter(M, StrtabBuilder, *Stream, Index,
4335                                        ModHash);
4336   ThinLinkWriter.write();
4337 }
4338 
4339 // Write the specified thin link bitcode file to the given raw output stream,
4340 // where it will be written in a new bitcode block. This is used when
4341 // writing the per-module index file for ThinLTO.
4342 void llvm::WriteThinLinkBitcodeToFile(const Module &M, raw_ostream &Out,
4343                                       const ModuleSummaryIndex &Index,
4344                                       const ModuleHash &ModHash) {
4345   SmallVector<char, 0> Buffer;
4346   Buffer.reserve(256 * 1024);
4347 
4348   BitcodeWriter Writer(Buffer);
4349   Writer.writeThinLinkBitcode(M, Index, ModHash);
4350   Writer.writeSymtab();
4351   Writer.writeStrtab();
4352 
4353   Out.write((char *)&Buffer.front(), Buffer.size());
4354 }
4355