xref: /llvm-project/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp (revision 6ed5706a2beab0bcde2a24e36751ea30cd5b4009)
1 //===- Bitcode/Writer/BitcodeWriter.cpp - Bitcode Writer ------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // Bitcode writer implementation.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "llvm/Bitcode/BitcodeWriter.h"
14 #include "ValueEnumerator.h"
15 #include "llvm/ADT/APFloat.h"
16 #include "llvm/ADT/APInt.h"
17 #include "llvm/ADT/ArrayRef.h"
18 #include "llvm/ADT/DenseMap.h"
19 #include "llvm/ADT/None.h"
20 #include "llvm/ADT/Optional.h"
21 #include "llvm/ADT/STLExtras.h"
22 #include "llvm/ADT/SmallString.h"
23 #include "llvm/ADT/SmallVector.h"
24 #include "llvm/ADT/StringMap.h"
25 #include "llvm/ADT/StringRef.h"
26 #include "llvm/ADT/Triple.h"
27 #include "llvm/Bitcode/BitCodes.h"
28 #include "llvm/Bitcode/BitstreamWriter.h"
29 #include "llvm/Bitcode/LLVMBitCodes.h"
30 #include "llvm/Config/llvm-config.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_UNOP_ABBREV,
115   FUNCTION_INST_UNOP_FLAGS_ABBREV,
116   FUNCTION_INST_BINOP_ABBREV,
117   FUNCTION_INST_BINOP_FLAGS_ABBREV,
118   FUNCTION_INST_CAST_ABBREV,
119   FUNCTION_INST_RET_VOID_ABBREV,
120   FUNCTION_INST_RET_VAL_ABBREV,
121   FUNCTION_INST_UNREACHABLE_ABBREV,
122   FUNCTION_INST_GEP_ABBREV,
123 };
124 
125 /// Abstract class to manage the bitcode writing, subclassed for each bitcode
126 /// file type.
127 class BitcodeWriterBase {
128 protected:
129   /// The stream created and owned by the client.
130   BitstreamWriter &Stream;
131 
132   StringTableBuilder &StrtabBuilder;
133 
134 public:
135   /// Constructs a BitcodeWriterBase object that writes to the provided
136   /// \p Stream.
137   BitcodeWriterBase(BitstreamWriter &Stream, StringTableBuilder &StrtabBuilder)
138       : Stream(Stream), StrtabBuilder(StrtabBuilder) {}
139 
140 protected:
141   void writeBitcodeHeader();
142   void writeModuleVersion();
143 };
144 
145 void BitcodeWriterBase::writeModuleVersion() {
146   // VERSION: [version#]
147   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, ArrayRef<uint64_t>{2});
148 }
149 
150 /// Base class to manage the module bitcode writing, currently subclassed for
151 /// ModuleBitcodeWriter and ThinLinkBitcodeWriter.
152 class ModuleBitcodeWriterBase : public BitcodeWriterBase {
153 protected:
154   /// The Module to write to bitcode.
155   const Module &M;
156 
157   /// Enumerates ids for all values in the module.
158   ValueEnumerator VE;
159 
160   /// Optional per-module index to write for ThinLTO.
161   const ModuleSummaryIndex *Index;
162 
163   /// Map that holds the correspondence between GUIDs in the summary index,
164   /// that came from indirect call profiles, and a value id generated by this
165   /// class to use in the VST and summary block records.
166   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
167 
168   /// Tracks the last value id recorded in the GUIDToValueMap.
169   unsigned GlobalValueId;
170 
171   /// Saves the offset of the VSTOffset record that must eventually be
172   /// backpatched with the offset of the actual VST.
173   uint64_t VSTOffsetPlaceholder = 0;
174 
175 public:
176   /// Constructs a ModuleBitcodeWriterBase object for the given Module,
177   /// writing to the provided \p Buffer.
178   ModuleBitcodeWriterBase(const Module &M, StringTableBuilder &StrtabBuilder,
179                           BitstreamWriter &Stream,
180                           bool ShouldPreserveUseListOrder,
181                           const ModuleSummaryIndex *Index)
182       : BitcodeWriterBase(Stream, StrtabBuilder), M(M),
183         VE(M, ShouldPreserveUseListOrder), Index(Index) {
184     // Assign ValueIds to any callee values in the index that came from
185     // indirect call profiles and were recorded as a GUID not a Value*
186     // (which would have been assigned an ID by the ValueEnumerator).
187     // The starting ValueId is just after the number of values in the
188     // ValueEnumerator, so that they can be emitted in the VST.
189     GlobalValueId = VE.getValues().size();
190     if (!Index)
191       return;
192     for (const auto &GUIDSummaryLists : *Index)
193       // Examine all summaries for this GUID.
194       for (auto &Summary : GUIDSummaryLists.second.SummaryList)
195         if (auto FS = dyn_cast<FunctionSummary>(Summary.get()))
196           // For each call in the function summary, see if the call
197           // is to a GUID (which means it is for an indirect call,
198           // otherwise we would have a Value for it). If so, synthesize
199           // a value id.
200           for (auto &CallEdge : FS->calls())
201             if (!CallEdge.first.haveGVs() || !CallEdge.first.getValue())
202               assignValueId(CallEdge.first.getGUID());
203   }
204 
205 protected:
206   void writePerModuleGlobalValueSummary();
207 
208 private:
209   void writePerModuleFunctionSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
210                                            GlobalValueSummary *Summary,
211                                            unsigned ValueID,
212                                            unsigned FSCallsAbbrev,
213                                            unsigned FSCallsProfileAbbrev,
214                                            const Function &F);
215   void writeModuleLevelReferences(const GlobalVariable &V,
216                                   SmallVector<uint64_t, 64> &NameVals,
217                                   unsigned FSModRefsAbbrev);
218 
219   void assignValueId(GlobalValue::GUID ValGUID) {
220     GUIDToValueIdMap[ValGUID] = ++GlobalValueId;
221   }
222 
223   unsigned getValueId(GlobalValue::GUID ValGUID) {
224     const auto &VMI = GUIDToValueIdMap.find(ValGUID);
225     // Expect that any GUID value had a value Id assigned by an
226     // earlier call to assignValueId.
227     assert(VMI != GUIDToValueIdMap.end() &&
228            "GUID does not have assigned value Id");
229     return VMI->second;
230   }
231 
232   // Helper to get the valueId for the type of value recorded in VI.
233   unsigned getValueId(ValueInfo VI) {
234     if (!VI.haveGVs() || !VI.getValue())
235       return getValueId(VI.getGUID());
236     return VE.getValueID(VI.getValue());
237   }
238 
239   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
240 };
241 
242 /// Class to manage the bitcode writing for a module.
243 class ModuleBitcodeWriter : public ModuleBitcodeWriterBase {
244   /// Pointer to the buffer allocated by caller for bitcode writing.
245   const SmallVectorImpl<char> &Buffer;
246 
247   /// True if a module hash record should be written.
248   bool GenerateHash;
249 
250   /// If non-null, when GenerateHash is true, the resulting hash is written
251   /// into ModHash.
252   ModuleHash *ModHash;
253 
254   SHA1 Hasher;
255 
256   /// The start bit of the identification block.
257   uint64_t BitcodeStartBit;
258 
259 public:
260   /// Constructs a ModuleBitcodeWriter object for the given Module,
261   /// writing to the provided \p Buffer.
262   ModuleBitcodeWriter(const Module &M, SmallVectorImpl<char> &Buffer,
263                       StringTableBuilder &StrtabBuilder,
264                       BitstreamWriter &Stream, bool ShouldPreserveUseListOrder,
265                       const ModuleSummaryIndex *Index, bool GenerateHash,
266                       ModuleHash *ModHash = nullptr)
267       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
268                                 ShouldPreserveUseListOrder, Index),
269         Buffer(Buffer), GenerateHash(GenerateHash), ModHash(ModHash),
270         BitcodeStartBit(Stream.GetCurrentBitNo()) {}
271 
272   /// Emit the current module to the bitstream.
273   void write();
274 
275 private:
276   uint64_t bitcodeStartBit() { return BitcodeStartBit; }
277 
278   size_t addToStrtab(StringRef Str);
279 
280   void writeAttributeGroupTable();
281   void writeAttributeTable();
282   void writeTypeTable();
283   void writeComdats();
284   void writeValueSymbolTableForwardDecl();
285   void writeModuleInfo();
286   void writeValueAsMetadata(const ValueAsMetadata *MD,
287                             SmallVectorImpl<uint64_t> &Record);
288   void writeMDTuple(const MDTuple *N, SmallVectorImpl<uint64_t> &Record,
289                     unsigned Abbrev);
290   unsigned createDILocationAbbrev();
291   void writeDILocation(const DILocation *N, SmallVectorImpl<uint64_t> &Record,
292                        unsigned &Abbrev);
293   unsigned createGenericDINodeAbbrev();
294   void writeGenericDINode(const GenericDINode *N,
295                           SmallVectorImpl<uint64_t> &Record, unsigned &Abbrev);
296   void writeDISubrange(const DISubrange *N, SmallVectorImpl<uint64_t> &Record,
297                        unsigned Abbrev);
298   void writeDIEnumerator(const DIEnumerator *N,
299                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
300   void writeDIBasicType(const DIBasicType *N, SmallVectorImpl<uint64_t> &Record,
301                         unsigned Abbrev);
302   void writeDIDerivedType(const DIDerivedType *N,
303                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
304   void writeDICompositeType(const DICompositeType *N,
305                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
306   void writeDISubroutineType(const DISubroutineType *N,
307                              SmallVectorImpl<uint64_t> &Record,
308                              unsigned Abbrev);
309   void writeDIFile(const DIFile *N, SmallVectorImpl<uint64_t> &Record,
310                    unsigned Abbrev);
311   void writeDICompileUnit(const DICompileUnit *N,
312                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
313   void writeDISubprogram(const DISubprogram *N,
314                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
315   void writeDILexicalBlock(const DILexicalBlock *N,
316                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
317   void writeDILexicalBlockFile(const DILexicalBlockFile *N,
318                                SmallVectorImpl<uint64_t> &Record,
319                                unsigned Abbrev);
320   void writeDICommonBlock(const DICommonBlock *N,
321                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
322   void writeDINamespace(const DINamespace *N, SmallVectorImpl<uint64_t> &Record,
323                         unsigned Abbrev);
324   void writeDIMacro(const DIMacro *N, SmallVectorImpl<uint64_t> &Record,
325                     unsigned Abbrev);
326   void writeDIMacroFile(const DIMacroFile *N, SmallVectorImpl<uint64_t> &Record,
327                         unsigned Abbrev);
328   void writeDIModule(const DIModule *N, SmallVectorImpl<uint64_t> &Record,
329                      unsigned Abbrev);
330   void writeDITemplateTypeParameter(const DITemplateTypeParameter *N,
331                                     SmallVectorImpl<uint64_t> &Record,
332                                     unsigned Abbrev);
333   void writeDITemplateValueParameter(const DITemplateValueParameter *N,
334                                      SmallVectorImpl<uint64_t> &Record,
335                                      unsigned Abbrev);
336   void writeDIGlobalVariable(const DIGlobalVariable *N,
337                              SmallVectorImpl<uint64_t> &Record,
338                              unsigned Abbrev);
339   void writeDILocalVariable(const DILocalVariable *N,
340                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
341   void writeDILabel(const DILabel *N,
342                     SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
343   void writeDIExpression(const DIExpression *N,
344                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
345   void writeDIGlobalVariableExpression(const DIGlobalVariableExpression *N,
346                                        SmallVectorImpl<uint64_t> &Record,
347                                        unsigned Abbrev);
348   void writeDIObjCProperty(const DIObjCProperty *N,
349                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
350   void writeDIImportedEntity(const DIImportedEntity *N,
351                              SmallVectorImpl<uint64_t> &Record,
352                              unsigned Abbrev);
353   unsigned createNamedMetadataAbbrev();
354   void writeNamedMetadata(SmallVectorImpl<uint64_t> &Record);
355   unsigned createMetadataStringsAbbrev();
356   void writeMetadataStrings(ArrayRef<const Metadata *> Strings,
357                             SmallVectorImpl<uint64_t> &Record);
358   void writeMetadataRecords(ArrayRef<const Metadata *> MDs,
359                             SmallVectorImpl<uint64_t> &Record,
360                             std::vector<unsigned> *MDAbbrevs = nullptr,
361                             std::vector<uint64_t> *IndexPos = nullptr);
362   void writeModuleMetadata();
363   void writeFunctionMetadata(const Function &F);
364   void writeFunctionMetadataAttachment(const Function &F);
365   void writeGlobalVariableMetadataAttachment(const GlobalVariable &GV);
366   void pushGlobalMetadataAttachment(SmallVectorImpl<uint64_t> &Record,
367                                     const GlobalObject &GO);
368   void writeModuleMetadataKinds();
369   void writeOperandBundleTags();
370   void writeSyncScopeNames();
371   void writeConstants(unsigned FirstVal, unsigned LastVal, bool isGlobal);
372   void writeModuleConstants();
373   bool pushValueAndType(const Value *V, unsigned InstID,
374                         SmallVectorImpl<unsigned> &Vals);
375   void writeOperandBundles(ImmutableCallSite CS, unsigned InstID);
376   void pushValue(const Value *V, unsigned InstID,
377                  SmallVectorImpl<unsigned> &Vals);
378   void pushValueSigned(const Value *V, unsigned InstID,
379                        SmallVectorImpl<uint64_t> &Vals);
380   void writeInstruction(const Instruction &I, unsigned InstID,
381                         SmallVectorImpl<unsigned> &Vals);
382   void writeFunctionLevelValueSymbolTable(const ValueSymbolTable &VST);
383   void writeGlobalValueSymbolTable(
384       DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
385   void writeUseList(UseListOrder &&Order);
386   void writeUseListBlock(const Function *F);
387   void
388   writeFunction(const Function &F,
389                 DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
390   void writeBlockInfo();
391   void writeModuleHash(size_t BlockStartPos);
392 
393   unsigned getEncodedSyncScopeID(SyncScope::ID SSID) {
394     return unsigned(SSID);
395   }
396 };
397 
398 /// Class to manage the bitcode writing for a combined index.
399 class IndexBitcodeWriter : public BitcodeWriterBase {
400   /// The combined index to write to bitcode.
401   const ModuleSummaryIndex &Index;
402 
403   /// When writing a subset of the index for distributed backends, client
404   /// provides a map of modules to the corresponding GUIDs/summaries to write.
405   const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex;
406 
407   /// Map that holds the correspondence between the GUID used in the combined
408   /// index and a value id generated by this class to use in references.
409   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
410 
411   /// Tracks the last value id recorded in the GUIDToValueMap.
412   unsigned GlobalValueId = 0;
413 
414 public:
415   /// Constructs a IndexBitcodeWriter object for the given combined index,
416   /// writing to the provided \p Buffer. When writing a subset of the index
417   /// for a distributed backend, provide a \p ModuleToSummariesForIndex map.
418   IndexBitcodeWriter(BitstreamWriter &Stream, StringTableBuilder &StrtabBuilder,
419                      const ModuleSummaryIndex &Index,
420                      const std::map<std::string, GVSummaryMapTy>
421                          *ModuleToSummariesForIndex = nullptr)
422       : BitcodeWriterBase(Stream, StrtabBuilder), Index(Index),
423         ModuleToSummariesForIndex(ModuleToSummariesForIndex) {
424     // Assign unique value ids to all summaries to be written, for use
425     // in writing out the call graph edges. Save the mapping from GUID
426     // to the new global value id to use when writing those edges, which
427     // are currently saved in the index in terms of GUID.
428     forEachSummary([&](GVInfo I, bool) {
429       GUIDToValueIdMap[I.first] = ++GlobalValueId;
430     });
431   }
432 
433   /// The below iterator returns the GUID and associated summary.
434   using GVInfo = std::pair<GlobalValue::GUID, GlobalValueSummary *>;
435 
436   /// Calls the callback for each value GUID and summary to be written to
437   /// bitcode. This hides the details of whether they are being pulled from the
438   /// entire index or just those in a provided ModuleToSummariesForIndex map.
439   template<typename Functor>
440   void forEachSummary(Functor Callback) {
441     if (ModuleToSummariesForIndex) {
442       for (auto &M : *ModuleToSummariesForIndex)
443         for (auto &Summary : M.second) {
444           Callback(Summary, false);
445           // Ensure aliasee is handled, e.g. for assigning a valueId,
446           // even if we are not importing the aliasee directly (the
447           // imported alias will contain a copy of aliasee).
448           if (auto *AS = dyn_cast<AliasSummary>(Summary.getSecond()))
449             Callback({AS->getAliaseeGUID(), &AS->getAliasee()}, true);
450         }
451     } else {
452       for (auto &Summaries : Index)
453         for (auto &Summary : Summaries.second.SummaryList)
454           Callback({Summaries.first, Summary.get()}, false);
455     }
456   }
457 
458   /// Calls the callback for each entry in the modulePaths StringMap that
459   /// should be written to the module path string table. This hides the details
460   /// of whether they are being pulled from the entire index or just those in a
461   /// provided ModuleToSummariesForIndex map.
462   template <typename Functor> void forEachModule(Functor Callback) {
463     if (ModuleToSummariesForIndex) {
464       for (const auto &M : *ModuleToSummariesForIndex) {
465         const auto &MPI = Index.modulePaths().find(M.first);
466         if (MPI == Index.modulePaths().end()) {
467           // This should only happen if the bitcode file was empty, in which
468           // case we shouldn't be importing (the ModuleToSummariesForIndex
469           // would only include the module we are writing and index for).
470           assert(ModuleToSummariesForIndex->size() == 1);
471           continue;
472         }
473         Callback(*MPI);
474       }
475     } else {
476       for (const auto &MPSE : Index.modulePaths())
477         Callback(MPSE);
478     }
479   }
480 
481   /// Main entry point for writing a combined index to bitcode.
482   void write();
483 
484 private:
485   void writeModStrings();
486   void writeCombinedGlobalValueSummary();
487 
488   Optional<unsigned> getValueId(GlobalValue::GUID ValGUID) {
489     auto VMI = GUIDToValueIdMap.find(ValGUID);
490     if (VMI == GUIDToValueIdMap.end())
491       return None;
492     return VMI->second;
493   }
494 
495   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
496 };
497 
498 } // end anonymous namespace
499 
500 static unsigned getEncodedCastOpcode(unsigned Opcode) {
501   switch (Opcode) {
502   default: llvm_unreachable("Unknown cast instruction!");
503   case Instruction::Trunc   : return bitc::CAST_TRUNC;
504   case Instruction::ZExt    : return bitc::CAST_ZEXT;
505   case Instruction::SExt    : return bitc::CAST_SEXT;
506   case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
507   case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
508   case Instruction::UIToFP  : return bitc::CAST_UITOFP;
509   case Instruction::SIToFP  : return bitc::CAST_SITOFP;
510   case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
511   case Instruction::FPExt   : return bitc::CAST_FPEXT;
512   case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
513   case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
514   case Instruction::BitCast : return bitc::CAST_BITCAST;
515   case Instruction::AddrSpaceCast: return bitc::CAST_ADDRSPACECAST;
516   }
517 }
518 
519 static unsigned getEncodedUnaryOpcode(unsigned Opcode) {
520   switch (Opcode) {
521   default: llvm_unreachable("Unknown binary instruction!");
522   case Instruction::FNeg: return bitc::UNOP_NEG;
523   }
524 }
525 
526 static unsigned getEncodedBinaryOpcode(unsigned Opcode) {
527   switch (Opcode) {
528   default: llvm_unreachable("Unknown binary instruction!");
529   case Instruction::Add:
530   case Instruction::FAdd: return bitc::BINOP_ADD;
531   case Instruction::Sub:
532   case Instruction::FSub: return bitc::BINOP_SUB;
533   case Instruction::Mul:
534   case Instruction::FMul: return bitc::BINOP_MUL;
535   case Instruction::UDiv: return bitc::BINOP_UDIV;
536   case Instruction::FDiv:
537   case Instruction::SDiv: return bitc::BINOP_SDIV;
538   case Instruction::URem: return bitc::BINOP_UREM;
539   case Instruction::FRem:
540   case Instruction::SRem: return bitc::BINOP_SREM;
541   case Instruction::Shl:  return bitc::BINOP_SHL;
542   case Instruction::LShr: return bitc::BINOP_LSHR;
543   case Instruction::AShr: return bitc::BINOP_ASHR;
544   case Instruction::And:  return bitc::BINOP_AND;
545   case Instruction::Or:   return bitc::BINOP_OR;
546   case Instruction::Xor:  return bitc::BINOP_XOR;
547   }
548 }
549 
550 static unsigned getEncodedRMWOperation(AtomicRMWInst::BinOp Op) {
551   switch (Op) {
552   default: llvm_unreachable("Unknown RMW operation!");
553   case AtomicRMWInst::Xchg: return bitc::RMW_XCHG;
554   case AtomicRMWInst::Add: return bitc::RMW_ADD;
555   case AtomicRMWInst::Sub: return bitc::RMW_SUB;
556   case AtomicRMWInst::And: return bitc::RMW_AND;
557   case AtomicRMWInst::Nand: return bitc::RMW_NAND;
558   case AtomicRMWInst::Or: return bitc::RMW_OR;
559   case AtomicRMWInst::Xor: return bitc::RMW_XOR;
560   case AtomicRMWInst::Max: return bitc::RMW_MAX;
561   case AtomicRMWInst::Min: return bitc::RMW_MIN;
562   case AtomicRMWInst::UMax: return bitc::RMW_UMAX;
563   case AtomicRMWInst::UMin: return bitc::RMW_UMIN;
564   case AtomicRMWInst::FAdd: return bitc::RMW_FADD;
565   case AtomicRMWInst::FSub: return bitc::RMW_FSUB;
566   }
567 }
568 
569 static unsigned getEncodedOrdering(AtomicOrdering Ordering) {
570   switch (Ordering) {
571   case AtomicOrdering::NotAtomic: return bitc::ORDERING_NOTATOMIC;
572   case AtomicOrdering::Unordered: return bitc::ORDERING_UNORDERED;
573   case AtomicOrdering::Monotonic: return bitc::ORDERING_MONOTONIC;
574   case AtomicOrdering::Acquire: return bitc::ORDERING_ACQUIRE;
575   case AtomicOrdering::Release: return bitc::ORDERING_RELEASE;
576   case AtomicOrdering::AcquireRelease: return bitc::ORDERING_ACQREL;
577   case AtomicOrdering::SequentiallyConsistent: return bitc::ORDERING_SEQCST;
578   }
579   llvm_unreachable("Invalid ordering");
580 }
581 
582 static void writeStringRecord(BitstreamWriter &Stream, unsigned Code,
583                               StringRef Str, unsigned AbbrevToUse) {
584   SmallVector<unsigned, 64> Vals;
585 
586   // Code: [strchar x N]
587   for (unsigned i = 0, e = Str.size(); i != e; ++i) {
588     if (AbbrevToUse && !BitCodeAbbrevOp::isChar6(Str[i]))
589       AbbrevToUse = 0;
590     Vals.push_back(Str[i]);
591   }
592 
593   // Emit the finished record.
594   Stream.EmitRecord(Code, Vals, AbbrevToUse);
595 }
596 
597 static uint64_t getAttrKindEncoding(Attribute::AttrKind Kind) {
598   switch (Kind) {
599   case Attribute::Alignment:
600     return bitc::ATTR_KIND_ALIGNMENT;
601   case Attribute::AllocSize:
602     return bitc::ATTR_KIND_ALLOC_SIZE;
603   case Attribute::AlwaysInline:
604     return bitc::ATTR_KIND_ALWAYS_INLINE;
605   case Attribute::ArgMemOnly:
606     return bitc::ATTR_KIND_ARGMEMONLY;
607   case Attribute::Builtin:
608     return bitc::ATTR_KIND_BUILTIN;
609   case Attribute::ByVal:
610     return bitc::ATTR_KIND_BY_VAL;
611   case Attribute::Convergent:
612     return bitc::ATTR_KIND_CONVERGENT;
613   case Attribute::InAlloca:
614     return bitc::ATTR_KIND_IN_ALLOCA;
615   case Attribute::Cold:
616     return bitc::ATTR_KIND_COLD;
617   case Attribute::InaccessibleMemOnly:
618     return bitc::ATTR_KIND_INACCESSIBLEMEM_ONLY;
619   case Attribute::InaccessibleMemOrArgMemOnly:
620     return bitc::ATTR_KIND_INACCESSIBLEMEM_OR_ARGMEMONLY;
621   case Attribute::InlineHint:
622     return bitc::ATTR_KIND_INLINE_HINT;
623   case Attribute::InReg:
624     return bitc::ATTR_KIND_IN_REG;
625   case Attribute::JumpTable:
626     return bitc::ATTR_KIND_JUMP_TABLE;
627   case Attribute::MinSize:
628     return bitc::ATTR_KIND_MIN_SIZE;
629   case Attribute::Naked:
630     return bitc::ATTR_KIND_NAKED;
631   case Attribute::Nest:
632     return bitc::ATTR_KIND_NEST;
633   case Attribute::NoAlias:
634     return bitc::ATTR_KIND_NO_ALIAS;
635   case Attribute::NoBuiltin:
636     return bitc::ATTR_KIND_NO_BUILTIN;
637   case Attribute::NoCapture:
638     return bitc::ATTR_KIND_NO_CAPTURE;
639   case Attribute::NoDuplicate:
640     return bitc::ATTR_KIND_NO_DUPLICATE;
641   case Attribute::NoImplicitFloat:
642     return bitc::ATTR_KIND_NO_IMPLICIT_FLOAT;
643   case Attribute::NoInline:
644     return bitc::ATTR_KIND_NO_INLINE;
645   case Attribute::NoRecurse:
646     return bitc::ATTR_KIND_NO_RECURSE;
647   case Attribute::NonLazyBind:
648     return bitc::ATTR_KIND_NON_LAZY_BIND;
649   case Attribute::NonNull:
650     return bitc::ATTR_KIND_NON_NULL;
651   case Attribute::Dereferenceable:
652     return bitc::ATTR_KIND_DEREFERENCEABLE;
653   case Attribute::DereferenceableOrNull:
654     return bitc::ATTR_KIND_DEREFERENCEABLE_OR_NULL;
655   case Attribute::NoRedZone:
656     return bitc::ATTR_KIND_NO_RED_ZONE;
657   case Attribute::NoReturn:
658     return bitc::ATTR_KIND_NO_RETURN;
659   case Attribute::NoCfCheck:
660     return bitc::ATTR_KIND_NOCF_CHECK;
661   case Attribute::NoUnwind:
662     return bitc::ATTR_KIND_NO_UNWIND;
663   case Attribute::OptForFuzzing:
664     return bitc::ATTR_KIND_OPT_FOR_FUZZING;
665   case Attribute::OptimizeForSize:
666     return bitc::ATTR_KIND_OPTIMIZE_FOR_SIZE;
667   case Attribute::OptimizeNone:
668     return bitc::ATTR_KIND_OPTIMIZE_NONE;
669   case Attribute::ReadNone:
670     return bitc::ATTR_KIND_READ_NONE;
671   case Attribute::ReadOnly:
672     return bitc::ATTR_KIND_READ_ONLY;
673   case Attribute::Returned:
674     return bitc::ATTR_KIND_RETURNED;
675   case Attribute::ReturnsTwice:
676     return bitc::ATTR_KIND_RETURNS_TWICE;
677   case Attribute::SExt:
678     return bitc::ATTR_KIND_S_EXT;
679   case Attribute::Speculatable:
680     return bitc::ATTR_KIND_SPECULATABLE;
681   case Attribute::StackAlignment:
682     return bitc::ATTR_KIND_STACK_ALIGNMENT;
683   case Attribute::StackProtect:
684     return bitc::ATTR_KIND_STACK_PROTECT;
685   case Attribute::StackProtectReq:
686     return bitc::ATTR_KIND_STACK_PROTECT_REQ;
687   case Attribute::StackProtectStrong:
688     return bitc::ATTR_KIND_STACK_PROTECT_STRONG;
689   case Attribute::SafeStack:
690     return bitc::ATTR_KIND_SAFESTACK;
691   case Attribute::ShadowCallStack:
692     return bitc::ATTR_KIND_SHADOWCALLSTACK;
693   case Attribute::StrictFP:
694     return bitc::ATTR_KIND_STRICT_FP;
695   case Attribute::StructRet:
696     return bitc::ATTR_KIND_STRUCT_RET;
697   case Attribute::SanitizeAddress:
698     return bitc::ATTR_KIND_SANITIZE_ADDRESS;
699   case Attribute::SanitizeHWAddress:
700     return bitc::ATTR_KIND_SANITIZE_HWADDRESS;
701   case Attribute::SanitizeThread:
702     return bitc::ATTR_KIND_SANITIZE_THREAD;
703   case Attribute::SanitizeMemory:
704     return bitc::ATTR_KIND_SANITIZE_MEMORY;
705   case Attribute::SpeculativeLoadHardening:
706     return bitc::ATTR_KIND_SPECULATIVE_LOAD_HARDENING;
707   case Attribute::SwiftError:
708     return bitc::ATTR_KIND_SWIFT_ERROR;
709   case Attribute::SwiftSelf:
710     return bitc::ATTR_KIND_SWIFT_SELF;
711   case Attribute::UWTable:
712     return bitc::ATTR_KIND_UW_TABLE;
713   case Attribute::WriteOnly:
714     return bitc::ATTR_KIND_WRITEONLY;
715   case Attribute::ZExt:
716     return bitc::ATTR_KIND_Z_EXT;
717   case Attribute::ImmArg:
718     return bitc::ATTR_KIND_IMMARG;
719   case Attribute::EndAttrKinds:
720     llvm_unreachable("Can not encode end-attribute kinds marker.");
721   case Attribute::None:
722     llvm_unreachable("Can not encode none-attribute.");
723   }
724 
725   llvm_unreachable("Trying to encode unknown attribute");
726 }
727 
728 void ModuleBitcodeWriter::writeAttributeGroupTable() {
729   const std::vector<ValueEnumerator::IndexAndAttrSet> &AttrGrps =
730       VE.getAttributeGroups();
731   if (AttrGrps.empty()) return;
732 
733   Stream.EnterSubblock(bitc::PARAMATTR_GROUP_BLOCK_ID, 3);
734 
735   SmallVector<uint64_t, 64> Record;
736   for (ValueEnumerator::IndexAndAttrSet Pair : AttrGrps) {
737     unsigned AttrListIndex = Pair.first;
738     AttributeSet AS = Pair.second;
739     Record.push_back(VE.getAttributeGroupID(Pair));
740     Record.push_back(AttrListIndex);
741 
742     for (Attribute Attr : AS) {
743       if (Attr.isEnumAttribute()) {
744         Record.push_back(0);
745         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
746       } else if (Attr.isIntAttribute()) {
747         Record.push_back(1);
748         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
749         Record.push_back(Attr.getValueAsInt());
750       } else {
751         StringRef Kind = Attr.getKindAsString();
752         StringRef Val = Attr.getValueAsString();
753 
754         Record.push_back(Val.empty() ? 3 : 4);
755         Record.append(Kind.begin(), Kind.end());
756         Record.push_back(0);
757         if (!Val.empty()) {
758           Record.append(Val.begin(), Val.end());
759           Record.push_back(0);
760         }
761       }
762     }
763 
764     Stream.EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
765     Record.clear();
766   }
767 
768   Stream.ExitBlock();
769 }
770 
771 void ModuleBitcodeWriter::writeAttributeTable() {
772   const std::vector<AttributeList> &Attrs = VE.getAttributeLists();
773   if (Attrs.empty()) return;
774 
775   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
776 
777   SmallVector<uint64_t, 64> Record;
778   for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
779     AttributeList AL = Attrs[i];
780     for (unsigned i = AL.index_begin(), e = AL.index_end(); i != e; ++i) {
781       AttributeSet AS = AL.getAttributes(i);
782       if (AS.hasAttributes())
783         Record.push_back(VE.getAttributeGroupID({i, AS}));
784     }
785 
786     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
787     Record.clear();
788   }
789 
790   Stream.ExitBlock();
791 }
792 
793 /// WriteTypeTable - Write out the type table for a module.
794 void ModuleBitcodeWriter::writeTypeTable() {
795   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
796 
797   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
798   SmallVector<uint64_t, 64> TypeVals;
799 
800   uint64_t NumBits = VE.computeBitsRequiredForTypeIndicies();
801 
802   // Abbrev for TYPE_CODE_POINTER.
803   auto Abbv = std::make_shared<BitCodeAbbrev>();
804   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
805   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
806   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
807   unsigned PtrAbbrev = Stream.EmitAbbrev(std::move(Abbv));
808 
809   // Abbrev for TYPE_CODE_FUNCTION.
810   Abbv = std::make_shared<BitCodeAbbrev>();
811   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
812   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
813   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
814   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
815   unsigned FunctionAbbrev = Stream.EmitAbbrev(std::move(Abbv));
816 
817   // Abbrev for TYPE_CODE_STRUCT_ANON.
818   Abbv = std::make_shared<BitCodeAbbrev>();
819   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
820   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
821   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
822   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
823   unsigned StructAnonAbbrev = Stream.EmitAbbrev(std::move(Abbv));
824 
825   // Abbrev for TYPE_CODE_STRUCT_NAME.
826   Abbv = std::make_shared<BitCodeAbbrev>();
827   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
828   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
829   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
830   unsigned StructNameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
831 
832   // Abbrev for TYPE_CODE_STRUCT_NAMED.
833   Abbv = std::make_shared<BitCodeAbbrev>();
834   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
835   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
836   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
837   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
838   unsigned StructNamedAbbrev = Stream.EmitAbbrev(std::move(Abbv));
839 
840   // Abbrev for TYPE_CODE_ARRAY.
841   Abbv = std::make_shared<BitCodeAbbrev>();
842   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
843   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
844   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
845   unsigned ArrayAbbrev = Stream.EmitAbbrev(std::move(Abbv));
846 
847   // Emit an entry count so the reader can reserve space.
848   TypeVals.push_back(TypeList.size());
849   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
850   TypeVals.clear();
851 
852   // Loop over all of the types, emitting each in turn.
853   for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
854     Type *T = TypeList[i];
855     int AbbrevToUse = 0;
856     unsigned Code = 0;
857 
858     switch (T->getTypeID()) {
859     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;      break;
860     case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;      break;
861     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;     break;
862     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE;    break;
863     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80;  break;
864     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128;     break;
865     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
866     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;     break;
867     case Type::MetadataTyID:  Code = bitc::TYPE_CODE_METADATA;  break;
868     case Type::X86_MMXTyID:   Code = bitc::TYPE_CODE_X86_MMX;   break;
869     case Type::TokenTyID:     Code = bitc::TYPE_CODE_TOKEN;     break;
870     case Type::IntegerTyID:
871       // INTEGER: [width]
872       Code = bitc::TYPE_CODE_INTEGER;
873       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
874       break;
875     case Type::PointerTyID: {
876       PointerType *PTy = cast<PointerType>(T);
877       // POINTER: [pointee type, address space]
878       Code = bitc::TYPE_CODE_POINTER;
879       TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
880       unsigned AddressSpace = PTy->getAddressSpace();
881       TypeVals.push_back(AddressSpace);
882       if (AddressSpace == 0) AbbrevToUse = PtrAbbrev;
883       break;
884     }
885     case Type::FunctionTyID: {
886       FunctionType *FT = cast<FunctionType>(T);
887       // FUNCTION: [isvararg, retty, paramty x N]
888       Code = bitc::TYPE_CODE_FUNCTION;
889       TypeVals.push_back(FT->isVarArg());
890       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
891       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
892         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
893       AbbrevToUse = FunctionAbbrev;
894       break;
895     }
896     case Type::StructTyID: {
897       StructType *ST = cast<StructType>(T);
898       // STRUCT: [ispacked, eltty x N]
899       TypeVals.push_back(ST->isPacked());
900       // Output all of the element types.
901       for (StructType::element_iterator I = ST->element_begin(),
902            E = ST->element_end(); I != E; ++I)
903         TypeVals.push_back(VE.getTypeID(*I));
904 
905       if (ST->isLiteral()) {
906         Code = bitc::TYPE_CODE_STRUCT_ANON;
907         AbbrevToUse = StructAnonAbbrev;
908       } else {
909         if (ST->isOpaque()) {
910           Code = bitc::TYPE_CODE_OPAQUE;
911         } else {
912           Code = bitc::TYPE_CODE_STRUCT_NAMED;
913           AbbrevToUse = StructNamedAbbrev;
914         }
915 
916         // Emit the name if it is present.
917         if (!ST->getName().empty())
918           writeStringRecord(Stream, bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
919                             StructNameAbbrev);
920       }
921       break;
922     }
923     case Type::ArrayTyID: {
924       ArrayType *AT = cast<ArrayType>(T);
925       // ARRAY: [numelts, eltty]
926       Code = bitc::TYPE_CODE_ARRAY;
927       TypeVals.push_back(AT->getNumElements());
928       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
929       AbbrevToUse = ArrayAbbrev;
930       break;
931     }
932     case Type::VectorTyID: {
933       VectorType *VT = cast<VectorType>(T);
934       // VECTOR [numelts, eltty]
935       Code = bitc::TYPE_CODE_VECTOR;
936       TypeVals.push_back(VT->getNumElements());
937       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
938       break;
939     }
940     }
941 
942     // Emit the finished record.
943     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
944     TypeVals.clear();
945   }
946 
947   Stream.ExitBlock();
948 }
949 
950 static unsigned getEncodedLinkage(const GlobalValue::LinkageTypes Linkage) {
951   switch (Linkage) {
952   case GlobalValue::ExternalLinkage:
953     return 0;
954   case GlobalValue::WeakAnyLinkage:
955     return 16;
956   case GlobalValue::AppendingLinkage:
957     return 2;
958   case GlobalValue::InternalLinkage:
959     return 3;
960   case GlobalValue::LinkOnceAnyLinkage:
961     return 18;
962   case GlobalValue::ExternalWeakLinkage:
963     return 7;
964   case GlobalValue::CommonLinkage:
965     return 8;
966   case GlobalValue::PrivateLinkage:
967     return 9;
968   case GlobalValue::WeakODRLinkage:
969     return 17;
970   case GlobalValue::LinkOnceODRLinkage:
971     return 19;
972   case GlobalValue::AvailableExternallyLinkage:
973     return 12;
974   }
975   llvm_unreachable("Invalid linkage");
976 }
977 
978 static unsigned getEncodedLinkage(const GlobalValue &GV) {
979   return getEncodedLinkage(GV.getLinkage());
980 }
981 
982 static uint64_t getEncodedFFlags(FunctionSummary::FFlags Flags) {
983   uint64_t RawFlags = 0;
984   RawFlags |= Flags.ReadNone;
985   RawFlags |= (Flags.ReadOnly << 1);
986   RawFlags |= (Flags.NoRecurse << 2);
987   RawFlags |= (Flags.ReturnDoesNotAlias << 3);
988   RawFlags |= (Flags.NoInline << 4);
989   return RawFlags;
990 }
991 
992 // Decode the flags for GlobalValue in the summary
993 static uint64_t getEncodedGVSummaryFlags(GlobalValueSummary::GVFlags Flags) {
994   uint64_t RawFlags = 0;
995 
996   RawFlags |= Flags.NotEligibleToImport; // bool
997   RawFlags |= (Flags.Live << 1);
998   RawFlags |= (Flags.DSOLocal << 2);
999 
1000   // Linkage don't need to be remapped at that time for the summary. Any future
1001   // change to the getEncodedLinkage() function will need to be taken into
1002   // account here as well.
1003   RawFlags = (RawFlags << 4) | Flags.Linkage; // 4 bits
1004 
1005   return RawFlags;
1006 }
1007 
1008 static uint64_t getEncodedGVarFlags(GlobalVarSummary::GVarFlags Flags) {
1009   uint64_t RawFlags = Flags.ReadOnly;
1010   return RawFlags;
1011 }
1012 
1013 static unsigned getEncodedVisibility(const GlobalValue &GV) {
1014   switch (GV.getVisibility()) {
1015   case GlobalValue::DefaultVisibility:   return 0;
1016   case GlobalValue::HiddenVisibility:    return 1;
1017   case GlobalValue::ProtectedVisibility: return 2;
1018   }
1019   llvm_unreachable("Invalid visibility");
1020 }
1021 
1022 static unsigned getEncodedDLLStorageClass(const GlobalValue &GV) {
1023   switch (GV.getDLLStorageClass()) {
1024   case GlobalValue::DefaultStorageClass:   return 0;
1025   case GlobalValue::DLLImportStorageClass: return 1;
1026   case GlobalValue::DLLExportStorageClass: return 2;
1027   }
1028   llvm_unreachable("Invalid DLL storage class");
1029 }
1030 
1031 static unsigned getEncodedThreadLocalMode(const GlobalValue &GV) {
1032   switch (GV.getThreadLocalMode()) {
1033     case GlobalVariable::NotThreadLocal:         return 0;
1034     case GlobalVariable::GeneralDynamicTLSModel: return 1;
1035     case GlobalVariable::LocalDynamicTLSModel:   return 2;
1036     case GlobalVariable::InitialExecTLSModel:    return 3;
1037     case GlobalVariable::LocalExecTLSModel:      return 4;
1038   }
1039   llvm_unreachable("Invalid TLS model");
1040 }
1041 
1042 static unsigned getEncodedComdatSelectionKind(const Comdat &C) {
1043   switch (C.getSelectionKind()) {
1044   case Comdat::Any:
1045     return bitc::COMDAT_SELECTION_KIND_ANY;
1046   case Comdat::ExactMatch:
1047     return bitc::COMDAT_SELECTION_KIND_EXACT_MATCH;
1048   case Comdat::Largest:
1049     return bitc::COMDAT_SELECTION_KIND_LARGEST;
1050   case Comdat::NoDuplicates:
1051     return bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES;
1052   case Comdat::SameSize:
1053     return bitc::COMDAT_SELECTION_KIND_SAME_SIZE;
1054   }
1055   llvm_unreachable("Invalid selection kind");
1056 }
1057 
1058 static unsigned getEncodedUnnamedAddr(const GlobalValue &GV) {
1059   switch (GV.getUnnamedAddr()) {
1060   case GlobalValue::UnnamedAddr::None:   return 0;
1061   case GlobalValue::UnnamedAddr::Local:  return 2;
1062   case GlobalValue::UnnamedAddr::Global: return 1;
1063   }
1064   llvm_unreachable("Invalid unnamed_addr");
1065 }
1066 
1067 size_t ModuleBitcodeWriter::addToStrtab(StringRef Str) {
1068   if (GenerateHash)
1069     Hasher.update(Str);
1070   return StrtabBuilder.add(Str);
1071 }
1072 
1073 void ModuleBitcodeWriter::writeComdats() {
1074   SmallVector<unsigned, 64> Vals;
1075   for (const Comdat *C : VE.getComdats()) {
1076     // COMDAT: [strtab offset, strtab size, selection_kind]
1077     Vals.push_back(addToStrtab(C->getName()));
1078     Vals.push_back(C->getName().size());
1079     Vals.push_back(getEncodedComdatSelectionKind(*C));
1080     Stream.EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
1081     Vals.clear();
1082   }
1083 }
1084 
1085 /// Write a record that will eventually hold the word offset of the
1086 /// module-level VST. For now the offset is 0, which will be backpatched
1087 /// after the real VST is written. Saves the bit offset to backpatch.
1088 void ModuleBitcodeWriter::writeValueSymbolTableForwardDecl() {
1089   // Write a placeholder value in for the offset of the real VST,
1090   // which is written after the function blocks so that it can include
1091   // the offset of each function. The placeholder offset will be
1092   // updated when the real VST is written.
1093   auto Abbv = std::make_shared<BitCodeAbbrev>();
1094   Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_VSTOFFSET));
1095   // Blocks are 32-bit aligned, so we can use a 32-bit word offset to
1096   // hold the real VST offset. Must use fixed instead of VBR as we don't
1097   // know how many VBR chunks to reserve ahead of time.
1098   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
1099   unsigned VSTOffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1100 
1101   // Emit the placeholder
1102   uint64_t Vals[] = {bitc::MODULE_CODE_VSTOFFSET, 0};
1103   Stream.EmitRecordWithAbbrev(VSTOffsetAbbrev, Vals);
1104 
1105   // Compute and save the bit offset to the placeholder, which will be
1106   // patched when the real VST is written. We can simply subtract the 32-bit
1107   // fixed size from the current bit number to get the location to backpatch.
1108   VSTOffsetPlaceholder = Stream.GetCurrentBitNo() - 32;
1109 }
1110 
1111 enum StringEncoding { SE_Char6, SE_Fixed7, SE_Fixed8 };
1112 
1113 /// Determine the encoding to use for the given string name and length.
1114 static StringEncoding getStringEncoding(StringRef Str) {
1115   bool isChar6 = true;
1116   for (char C : Str) {
1117     if (isChar6)
1118       isChar6 = BitCodeAbbrevOp::isChar6(C);
1119     if ((unsigned char)C & 128)
1120       // don't bother scanning the rest.
1121       return SE_Fixed8;
1122   }
1123   if (isChar6)
1124     return SE_Char6;
1125   return SE_Fixed7;
1126 }
1127 
1128 /// Emit top-level description of module, including target triple, inline asm,
1129 /// descriptors for global variables, and function prototype info.
1130 /// Returns the bit offset to backpatch with the location of the real VST.
1131 void ModuleBitcodeWriter::writeModuleInfo() {
1132   // Emit various pieces of data attached to a module.
1133   if (!M.getTargetTriple().empty())
1134     writeStringRecord(Stream, bitc::MODULE_CODE_TRIPLE, M.getTargetTriple(),
1135                       0 /*TODO*/);
1136   const std::string &DL = M.getDataLayoutStr();
1137   if (!DL.empty())
1138     writeStringRecord(Stream, bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/);
1139   if (!M.getModuleInlineAsm().empty())
1140     writeStringRecord(Stream, bitc::MODULE_CODE_ASM, M.getModuleInlineAsm(),
1141                       0 /*TODO*/);
1142 
1143   // Emit information about sections and GC, computing how many there are. Also
1144   // compute the maximum alignment value.
1145   std::map<std::string, unsigned> SectionMap;
1146   std::map<std::string, unsigned> GCMap;
1147   unsigned MaxAlignment = 0;
1148   unsigned MaxGlobalType = 0;
1149   for (const GlobalValue &GV : M.globals()) {
1150     MaxAlignment = std::max(MaxAlignment, GV.getAlignment());
1151     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getValueType()));
1152     if (GV.hasSection()) {
1153       // Give section names unique ID's.
1154       unsigned &Entry = SectionMap[GV.getSection()];
1155       if (!Entry) {
1156         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
1157                           0 /*TODO*/);
1158         Entry = SectionMap.size();
1159       }
1160     }
1161   }
1162   for (const Function &F : M) {
1163     MaxAlignment = std::max(MaxAlignment, F.getAlignment());
1164     if (F.hasSection()) {
1165       // Give section names unique ID's.
1166       unsigned &Entry = SectionMap[F.getSection()];
1167       if (!Entry) {
1168         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
1169                           0 /*TODO*/);
1170         Entry = SectionMap.size();
1171       }
1172     }
1173     if (F.hasGC()) {
1174       // Same for GC names.
1175       unsigned &Entry = GCMap[F.getGC()];
1176       if (!Entry) {
1177         writeStringRecord(Stream, bitc::MODULE_CODE_GCNAME, F.getGC(),
1178                           0 /*TODO*/);
1179         Entry = GCMap.size();
1180       }
1181     }
1182   }
1183 
1184   // Emit abbrev for globals, now that we know # sections and max alignment.
1185   unsigned SimpleGVarAbbrev = 0;
1186   if (!M.global_empty()) {
1187     // Add an abbrev for common globals with no visibility or thread localness.
1188     auto Abbv = std::make_shared<BitCodeAbbrev>();
1189     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
1190     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1191     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1192     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1193                               Log2_32_Ceil(MaxGlobalType+1)));
1194     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddrSpace << 2
1195                                                            //| explicitType << 1
1196                                                            //| constant
1197     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Initializer.
1198     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // Linkage.
1199     if (MaxAlignment == 0)                                 // Alignment.
1200       Abbv->Add(BitCodeAbbrevOp(0));
1201     else {
1202       unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
1203       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1204                                Log2_32_Ceil(MaxEncAlignment+1)));
1205     }
1206     if (SectionMap.empty())                                    // Section.
1207       Abbv->Add(BitCodeAbbrevOp(0));
1208     else
1209       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1210                                Log2_32_Ceil(SectionMap.size()+1)));
1211     // Don't bother emitting vis + thread local.
1212     SimpleGVarAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1213   }
1214 
1215   SmallVector<unsigned, 64> Vals;
1216   // Emit the module's source file name.
1217   {
1218     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
1219     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
1220     if (Bits == SE_Char6)
1221       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
1222     else if (Bits == SE_Fixed7)
1223       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
1224 
1225     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
1226     auto Abbv = std::make_shared<BitCodeAbbrev>();
1227     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
1228     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1229     Abbv->Add(AbbrevOpToUse);
1230     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1231 
1232     for (const auto P : M.getSourceFileName())
1233       Vals.push_back((unsigned char)P);
1234 
1235     // Emit the finished record.
1236     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
1237     Vals.clear();
1238   }
1239 
1240   // Emit the global variable information.
1241   for (const GlobalVariable &GV : M.globals()) {
1242     unsigned AbbrevToUse = 0;
1243 
1244     // GLOBALVAR: [strtab offset, strtab size, type, isconst, initid,
1245     //             linkage, alignment, section, visibility, threadlocal,
1246     //             unnamed_addr, externally_initialized, dllstorageclass,
1247     //             comdat, attributes, DSO_Local]
1248     Vals.push_back(addToStrtab(GV.getName()));
1249     Vals.push_back(GV.getName().size());
1250     Vals.push_back(VE.getTypeID(GV.getValueType()));
1251     Vals.push_back(GV.getType()->getAddressSpace() << 2 | 2 | GV.isConstant());
1252     Vals.push_back(GV.isDeclaration() ? 0 :
1253                    (VE.getValueID(GV.getInitializer()) + 1));
1254     Vals.push_back(getEncodedLinkage(GV));
1255     Vals.push_back(Log2_32(GV.getAlignment())+1);
1256     Vals.push_back(GV.hasSection() ? SectionMap[GV.getSection()] : 0);
1257     if (GV.isThreadLocal() ||
1258         GV.getVisibility() != GlobalValue::DefaultVisibility ||
1259         GV.getUnnamedAddr() != GlobalValue::UnnamedAddr::None ||
1260         GV.isExternallyInitialized() ||
1261         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
1262         GV.hasComdat() ||
1263         GV.hasAttributes() ||
1264         GV.isDSOLocal()) {
1265       Vals.push_back(getEncodedVisibility(GV));
1266       Vals.push_back(getEncodedThreadLocalMode(GV));
1267       Vals.push_back(getEncodedUnnamedAddr(GV));
1268       Vals.push_back(GV.isExternallyInitialized());
1269       Vals.push_back(getEncodedDLLStorageClass(GV));
1270       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
1271 
1272       auto AL = GV.getAttributesAsList(AttributeList::FunctionIndex);
1273       Vals.push_back(VE.getAttributeListID(AL));
1274 
1275       Vals.push_back(GV.isDSOLocal());
1276     } else {
1277       AbbrevToUse = SimpleGVarAbbrev;
1278     }
1279 
1280     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
1281     Vals.clear();
1282   }
1283 
1284   // Emit the function proto information.
1285   for (const Function &F : M) {
1286     // FUNCTION:  [strtab offset, strtab size, type, callingconv, isproto,
1287     //             linkage, paramattrs, alignment, section, visibility, gc,
1288     //             unnamed_addr, prologuedata, dllstorageclass, comdat,
1289     //             prefixdata, personalityfn, DSO_Local, addrspace]
1290     Vals.push_back(addToStrtab(F.getName()));
1291     Vals.push_back(F.getName().size());
1292     Vals.push_back(VE.getTypeID(F.getFunctionType()));
1293     Vals.push_back(F.getCallingConv());
1294     Vals.push_back(F.isDeclaration());
1295     Vals.push_back(getEncodedLinkage(F));
1296     Vals.push_back(VE.getAttributeListID(F.getAttributes()));
1297     Vals.push_back(Log2_32(F.getAlignment())+1);
1298     Vals.push_back(F.hasSection() ? SectionMap[F.getSection()] : 0);
1299     Vals.push_back(getEncodedVisibility(F));
1300     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
1301     Vals.push_back(getEncodedUnnamedAddr(F));
1302     Vals.push_back(F.hasPrologueData() ? (VE.getValueID(F.getPrologueData()) + 1)
1303                                        : 0);
1304     Vals.push_back(getEncodedDLLStorageClass(F));
1305     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
1306     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
1307                                      : 0);
1308     Vals.push_back(
1309         F.hasPersonalityFn() ? (VE.getValueID(F.getPersonalityFn()) + 1) : 0);
1310 
1311     Vals.push_back(F.isDSOLocal());
1312     Vals.push_back(F.getAddressSpace());
1313 
1314     unsigned AbbrevToUse = 0;
1315     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
1316     Vals.clear();
1317   }
1318 
1319   // Emit the alias information.
1320   for (const GlobalAlias &A : M.aliases()) {
1321     // ALIAS: [strtab offset, strtab size, alias type, aliasee val#, linkage,
1322     //         visibility, dllstorageclass, threadlocal, unnamed_addr,
1323     //         DSO_Local]
1324     Vals.push_back(addToStrtab(A.getName()));
1325     Vals.push_back(A.getName().size());
1326     Vals.push_back(VE.getTypeID(A.getValueType()));
1327     Vals.push_back(A.getType()->getAddressSpace());
1328     Vals.push_back(VE.getValueID(A.getAliasee()));
1329     Vals.push_back(getEncodedLinkage(A));
1330     Vals.push_back(getEncodedVisibility(A));
1331     Vals.push_back(getEncodedDLLStorageClass(A));
1332     Vals.push_back(getEncodedThreadLocalMode(A));
1333     Vals.push_back(getEncodedUnnamedAddr(A));
1334     Vals.push_back(A.isDSOLocal());
1335 
1336     unsigned AbbrevToUse = 0;
1337     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
1338     Vals.clear();
1339   }
1340 
1341   // Emit the ifunc information.
1342   for (const GlobalIFunc &I : M.ifuncs()) {
1343     // IFUNC: [strtab offset, strtab size, ifunc type, address space, resolver
1344     //         val#, linkage, visibility, DSO_Local]
1345     Vals.push_back(addToStrtab(I.getName()));
1346     Vals.push_back(I.getName().size());
1347     Vals.push_back(VE.getTypeID(I.getValueType()));
1348     Vals.push_back(I.getType()->getAddressSpace());
1349     Vals.push_back(VE.getValueID(I.getResolver()));
1350     Vals.push_back(getEncodedLinkage(I));
1351     Vals.push_back(getEncodedVisibility(I));
1352     Vals.push_back(I.isDSOLocal());
1353     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
1354     Vals.clear();
1355   }
1356 
1357   writeValueSymbolTableForwardDecl();
1358 }
1359 
1360 static uint64_t getOptimizationFlags(const Value *V) {
1361   uint64_t Flags = 0;
1362 
1363   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
1364     if (OBO->hasNoSignedWrap())
1365       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
1366     if (OBO->hasNoUnsignedWrap())
1367       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
1368   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
1369     if (PEO->isExact())
1370       Flags |= 1 << bitc::PEO_EXACT;
1371   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
1372     if (FPMO->hasAllowReassoc())
1373       Flags |= bitc::AllowReassoc;
1374     if (FPMO->hasNoNaNs())
1375       Flags |= bitc::NoNaNs;
1376     if (FPMO->hasNoInfs())
1377       Flags |= bitc::NoInfs;
1378     if (FPMO->hasNoSignedZeros())
1379       Flags |= bitc::NoSignedZeros;
1380     if (FPMO->hasAllowReciprocal())
1381       Flags |= bitc::AllowReciprocal;
1382     if (FPMO->hasAllowContract())
1383       Flags |= bitc::AllowContract;
1384     if (FPMO->hasApproxFunc())
1385       Flags |= bitc::ApproxFunc;
1386   }
1387 
1388   return Flags;
1389 }
1390 
1391 void ModuleBitcodeWriter::writeValueAsMetadata(
1392     const ValueAsMetadata *MD, SmallVectorImpl<uint64_t> &Record) {
1393   // Mimic an MDNode with a value as one operand.
1394   Value *V = MD->getValue();
1395   Record.push_back(VE.getTypeID(V->getType()));
1396   Record.push_back(VE.getValueID(V));
1397   Stream.EmitRecord(bitc::METADATA_VALUE, Record, 0);
1398   Record.clear();
1399 }
1400 
1401 void ModuleBitcodeWriter::writeMDTuple(const MDTuple *N,
1402                                        SmallVectorImpl<uint64_t> &Record,
1403                                        unsigned Abbrev) {
1404   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
1405     Metadata *MD = N->getOperand(i);
1406     assert(!(MD && isa<LocalAsMetadata>(MD)) &&
1407            "Unexpected function-local metadata");
1408     Record.push_back(VE.getMetadataOrNullID(MD));
1409   }
1410   Stream.EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
1411                                     : bitc::METADATA_NODE,
1412                     Record, Abbrev);
1413   Record.clear();
1414 }
1415 
1416 unsigned ModuleBitcodeWriter::createDILocationAbbrev() {
1417   // Assume the column is usually under 128, and always output the inlined-at
1418   // location (it's never more expensive than building an array size 1).
1419   auto Abbv = std::make_shared<BitCodeAbbrev>();
1420   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
1421   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1422   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1423   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1424   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1425   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1426   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1427   return Stream.EmitAbbrev(std::move(Abbv));
1428 }
1429 
1430 void ModuleBitcodeWriter::writeDILocation(const DILocation *N,
1431                                           SmallVectorImpl<uint64_t> &Record,
1432                                           unsigned &Abbrev) {
1433   if (!Abbrev)
1434     Abbrev = createDILocationAbbrev();
1435 
1436   Record.push_back(N->isDistinct());
1437   Record.push_back(N->getLine());
1438   Record.push_back(N->getColumn());
1439   Record.push_back(VE.getMetadataID(N->getScope()));
1440   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
1441   Record.push_back(N->isImplicitCode());
1442 
1443   Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
1444   Record.clear();
1445 }
1446 
1447 unsigned ModuleBitcodeWriter::createGenericDINodeAbbrev() {
1448   // Assume the column is usually under 128, and always output the inlined-at
1449   // location (it's never more expensive than building an array size 1).
1450   auto Abbv = std::make_shared<BitCodeAbbrev>();
1451   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
1452   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1453   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1454   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1455   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1456   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1457   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1458   return Stream.EmitAbbrev(std::move(Abbv));
1459 }
1460 
1461 void ModuleBitcodeWriter::writeGenericDINode(const GenericDINode *N,
1462                                              SmallVectorImpl<uint64_t> &Record,
1463                                              unsigned &Abbrev) {
1464   if (!Abbrev)
1465     Abbrev = createGenericDINodeAbbrev();
1466 
1467   Record.push_back(N->isDistinct());
1468   Record.push_back(N->getTag());
1469   Record.push_back(0); // Per-tag version field; unused for now.
1470 
1471   for (auto &I : N->operands())
1472     Record.push_back(VE.getMetadataOrNullID(I));
1473 
1474   Stream.EmitRecord(bitc::METADATA_GENERIC_DEBUG, Record, Abbrev);
1475   Record.clear();
1476 }
1477 
1478 static uint64_t rotateSign(int64_t I) {
1479   uint64_t U = I;
1480   return I < 0 ? ~(U << 1) : U << 1;
1481 }
1482 
1483 void ModuleBitcodeWriter::writeDISubrange(const DISubrange *N,
1484                                           SmallVectorImpl<uint64_t> &Record,
1485                                           unsigned Abbrev) {
1486   const uint64_t Version = 1 << 1;
1487   Record.push_back((uint64_t)N->isDistinct() | Version);
1488   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1489   Record.push_back(rotateSign(N->getLowerBound()));
1490 
1491   Stream.EmitRecord(bitc::METADATA_SUBRANGE, Record, Abbrev);
1492   Record.clear();
1493 }
1494 
1495 void ModuleBitcodeWriter::writeDIEnumerator(const DIEnumerator *N,
1496                                             SmallVectorImpl<uint64_t> &Record,
1497                                             unsigned Abbrev) {
1498   Record.push_back((N->isUnsigned() << 1) | N->isDistinct());
1499   Record.push_back(rotateSign(N->getValue()));
1500   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1501 
1502   Stream.EmitRecord(bitc::METADATA_ENUMERATOR, Record, Abbrev);
1503   Record.clear();
1504 }
1505 
1506 void ModuleBitcodeWriter::writeDIBasicType(const DIBasicType *N,
1507                                            SmallVectorImpl<uint64_t> &Record,
1508                                            unsigned Abbrev) {
1509   Record.push_back(N->isDistinct());
1510   Record.push_back(N->getTag());
1511   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1512   Record.push_back(N->getSizeInBits());
1513   Record.push_back(N->getAlignInBits());
1514   Record.push_back(N->getEncoding());
1515   Record.push_back(N->getFlags());
1516 
1517   Stream.EmitRecord(bitc::METADATA_BASIC_TYPE, Record, Abbrev);
1518   Record.clear();
1519 }
1520 
1521 void ModuleBitcodeWriter::writeDIDerivedType(const DIDerivedType *N,
1522                                              SmallVectorImpl<uint64_t> &Record,
1523                                              unsigned Abbrev) {
1524   Record.push_back(N->isDistinct());
1525   Record.push_back(N->getTag());
1526   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1527   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1528   Record.push_back(N->getLine());
1529   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1530   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1531   Record.push_back(N->getSizeInBits());
1532   Record.push_back(N->getAlignInBits());
1533   Record.push_back(N->getOffsetInBits());
1534   Record.push_back(N->getFlags());
1535   Record.push_back(VE.getMetadataOrNullID(N->getExtraData()));
1536 
1537   // DWARF address space is encoded as N->getDWARFAddressSpace() + 1. 0 means
1538   // that there is no DWARF address space associated with DIDerivedType.
1539   if (const auto &DWARFAddressSpace = N->getDWARFAddressSpace())
1540     Record.push_back(*DWARFAddressSpace + 1);
1541   else
1542     Record.push_back(0);
1543 
1544   Stream.EmitRecord(bitc::METADATA_DERIVED_TYPE, Record, Abbrev);
1545   Record.clear();
1546 }
1547 
1548 void ModuleBitcodeWriter::writeDICompositeType(
1549     const DICompositeType *N, SmallVectorImpl<uint64_t> &Record,
1550     unsigned Abbrev) {
1551   const unsigned IsNotUsedInOldTypeRef = 0x2;
1552   Record.push_back(IsNotUsedInOldTypeRef | (unsigned)N->isDistinct());
1553   Record.push_back(N->getTag());
1554   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1555   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1556   Record.push_back(N->getLine());
1557   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1558   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1559   Record.push_back(N->getSizeInBits());
1560   Record.push_back(N->getAlignInBits());
1561   Record.push_back(N->getOffsetInBits());
1562   Record.push_back(N->getFlags());
1563   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1564   Record.push_back(N->getRuntimeLang());
1565   Record.push_back(VE.getMetadataOrNullID(N->getVTableHolder()));
1566   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1567   Record.push_back(VE.getMetadataOrNullID(N->getRawIdentifier()));
1568   Record.push_back(VE.getMetadataOrNullID(N->getDiscriminator()));
1569 
1570   Stream.EmitRecord(bitc::METADATA_COMPOSITE_TYPE, Record, Abbrev);
1571   Record.clear();
1572 }
1573 
1574 void ModuleBitcodeWriter::writeDISubroutineType(
1575     const DISubroutineType *N, SmallVectorImpl<uint64_t> &Record,
1576     unsigned Abbrev) {
1577   const unsigned HasNoOldTypeRefs = 0x2;
1578   Record.push_back(HasNoOldTypeRefs | (unsigned)N->isDistinct());
1579   Record.push_back(N->getFlags());
1580   Record.push_back(VE.getMetadataOrNullID(N->getTypeArray().get()));
1581   Record.push_back(N->getCC());
1582 
1583   Stream.EmitRecord(bitc::METADATA_SUBROUTINE_TYPE, Record, Abbrev);
1584   Record.clear();
1585 }
1586 
1587 void ModuleBitcodeWriter::writeDIFile(const DIFile *N,
1588                                       SmallVectorImpl<uint64_t> &Record,
1589                                       unsigned Abbrev) {
1590   Record.push_back(N->isDistinct());
1591   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
1592   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
1593   if (N->getRawChecksum()) {
1594     Record.push_back(N->getRawChecksum()->Kind);
1595     Record.push_back(VE.getMetadataOrNullID(N->getRawChecksum()->Value));
1596   } else {
1597     // Maintain backwards compatibility with the old internal representation of
1598     // CSK_None in ChecksumKind by writing nulls here when Checksum is None.
1599     Record.push_back(0);
1600     Record.push_back(VE.getMetadataOrNullID(nullptr));
1601   }
1602   auto Source = N->getRawSource();
1603   if (Source)
1604     Record.push_back(VE.getMetadataOrNullID(*Source));
1605 
1606   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
1607   Record.clear();
1608 }
1609 
1610 void ModuleBitcodeWriter::writeDICompileUnit(const DICompileUnit *N,
1611                                              SmallVectorImpl<uint64_t> &Record,
1612                                              unsigned Abbrev) {
1613   assert(N->isDistinct() && "Expected distinct compile units");
1614   Record.push_back(/* IsDistinct */ true);
1615   Record.push_back(N->getSourceLanguage());
1616   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1617   Record.push_back(VE.getMetadataOrNullID(N->getRawProducer()));
1618   Record.push_back(N->isOptimized());
1619   Record.push_back(VE.getMetadataOrNullID(N->getRawFlags()));
1620   Record.push_back(N->getRuntimeVersion());
1621   Record.push_back(VE.getMetadataOrNullID(N->getRawSplitDebugFilename()));
1622   Record.push_back(N->getEmissionKind());
1623   Record.push_back(VE.getMetadataOrNullID(N->getEnumTypes().get()));
1624   Record.push_back(VE.getMetadataOrNullID(N->getRetainedTypes().get()));
1625   Record.push_back(/* subprograms */ 0);
1626   Record.push_back(VE.getMetadataOrNullID(N->getGlobalVariables().get()));
1627   Record.push_back(VE.getMetadataOrNullID(N->getImportedEntities().get()));
1628   Record.push_back(N->getDWOId());
1629   Record.push_back(VE.getMetadataOrNullID(N->getMacros().get()));
1630   Record.push_back(N->getSplitDebugInlining());
1631   Record.push_back(N->getDebugInfoForProfiling());
1632   Record.push_back((unsigned)N->getNameTableKind());
1633 
1634   Stream.EmitRecord(bitc::METADATA_COMPILE_UNIT, Record, Abbrev);
1635   Record.clear();
1636 }
1637 
1638 void ModuleBitcodeWriter::writeDISubprogram(const DISubprogram *N,
1639                                             SmallVectorImpl<uint64_t> &Record,
1640                                             unsigned Abbrev) {
1641   const uint64_t HasUnitFlag = 1 << 1;
1642   const uint64_t HasSPFlagsFlag = 1 << 2;
1643   Record.push_back(uint64_t(N->isDistinct()) | HasUnitFlag | HasSPFlagsFlag);
1644   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1645   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1646   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1647   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1648   Record.push_back(N->getLine());
1649   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1650   Record.push_back(N->getScopeLine());
1651   Record.push_back(VE.getMetadataOrNullID(N->getContainingType()));
1652   Record.push_back(N->getSPFlags());
1653   Record.push_back(N->getVirtualIndex());
1654   Record.push_back(N->getFlags());
1655   Record.push_back(VE.getMetadataOrNullID(N->getRawUnit()));
1656   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1657   Record.push_back(VE.getMetadataOrNullID(N->getDeclaration()));
1658   Record.push_back(VE.getMetadataOrNullID(N->getRetainedNodes().get()));
1659   Record.push_back(N->getThisAdjustment());
1660   Record.push_back(VE.getMetadataOrNullID(N->getThrownTypes().get()));
1661 
1662   Stream.EmitRecord(bitc::METADATA_SUBPROGRAM, Record, Abbrev);
1663   Record.clear();
1664 }
1665 
1666 void ModuleBitcodeWriter::writeDILexicalBlock(const DILexicalBlock *N,
1667                                               SmallVectorImpl<uint64_t> &Record,
1668                                               unsigned Abbrev) {
1669   Record.push_back(N->isDistinct());
1670   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1671   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1672   Record.push_back(N->getLine());
1673   Record.push_back(N->getColumn());
1674 
1675   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK, Record, Abbrev);
1676   Record.clear();
1677 }
1678 
1679 void ModuleBitcodeWriter::writeDILexicalBlockFile(
1680     const DILexicalBlockFile *N, SmallVectorImpl<uint64_t> &Record,
1681     unsigned Abbrev) {
1682   Record.push_back(N->isDistinct());
1683   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1684   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1685   Record.push_back(N->getDiscriminator());
1686 
1687   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK_FILE, Record, Abbrev);
1688   Record.clear();
1689 }
1690 
1691 void ModuleBitcodeWriter::writeDICommonBlock(const DICommonBlock *N,
1692                                              SmallVectorImpl<uint64_t> &Record,
1693                                              unsigned Abbrev) {
1694   Record.push_back(N->isDistinct());
1695   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1696   Record.push_back(VE.getMetadataOrNullID(N->getDecl()));
1697   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1698   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1699   Record.push_back(N->getLineNo());
1700 
1701   Stream.EmitRecord(bitc::METADATA_COMMON_BLOCK, Record, Abbrev);
1702   Record.clear();
1703 }
1704 
1705 void ModuleBitcodeWriter::writeDINamespace(const DINamespace *N,
1706                                            SmallVectorImpl<uint64_t> &Record,
1707                                            unsigned Abbrev) {
1708   Record.push_back(N->isDistinct() | N->getExportSymbols() << 1);
1709   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1710   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1711 
1712   Stream.EmitRecord(bitc::METADATA_NAMESPACE, Record, Abbrev);
1713   Record.clear();
1714 }
1715 
1716 void ModuleBitcodeWriter::writeDIMacro(const DIMacro *N,
1717                                        SmallVectorImpl<uint64_t> &Record,
1718                                        unsigned Abbrev) {
1719   Record.push_back(N->isDistinct());
1720   Record.push_back(N->getMacinfoType());
1721   Record.push_back(N->getLine());
1722   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1723   Record.push_back(VE.getMetadataOrNullID(N->getRawValue()));
1724 
1725   Stream.EmitRecord(bitc::METADATA_MACRO, Record, Abbrev);
1726   Record.clear();
1727 }
1728 
1729 void ModuleBitcodeWriter::writeDIMacroFile(const DIMacroFile *N,
1730                                            SmallVectorImpl<uint64_t> &Record,
1731                                            unsigned Abbrev) {
1732   Record.push_back(N->isDistinct());
1733   Record.push_back(N->getMacinfoType());
1734   Record.push_back(N->getLine());
1735   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1736   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1737 
1738   Stream.EmitRecord(bitc::METADATA_MACRO_FILE, Record, Abbrev);
1739   Record.clear();
1740 }
1741 
1742 void ModuleBitcodeWriter::writeDIModule(const DIModule *N,
1743                                         SmallVectorImpl<uint64_t> &Record,
1744                                         unsigned Abbrev) {
1745   Record.push_back(N->isDistinct());
1746   for (auto &I : N->operands())
1747     Record.push_back(VE.getMetadataOrNullID(I));
1748 
1749   Stream.EmitRecord(bitc::METADATA_MODULE, Record, Abbrev);
1750   Record.clear();
1751 }
1752 
1753 void ModuleBitcodeWriter::writeDITemplateTypeParameter(
1754     const DITemplateTypeParameter *N, SmallVectorImpl<uint64_t> &Record,
1755     unsigned Abbrev) {
1756   Record.push_back(N->isDistinct());
1757   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1758   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1759 
1760   Stream.EmitRecord(bitc::METADATA_TEMPLATE_TYPE, Record, Abbrev);
1761   Record.clear();
1762 }
1763 
1764 void ModuleBitcodeWriter::writeDITemplateValueParameter(
1765     const DITemplateValueParameter *N, SmallVectorImpl<uint64_t> &Record,
1766     unsigned Abbrev) {
1767   Record.push_back(N->isDistinct());
1768   Record.push_back(N->getTag());
1769   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1770   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1771   Record.push_back(VE.getMetadataOrNullID(N->getValue()));
1772 
1773   Stream.EmitRecord(bitc::METADATA_TEMPLATE_VALUE, Record, Abbrev);
1774   Record.clear();
1775 }
1776 
1777 void ModuleBitcodeWriter::writeDIGlobalVariable(
1778     const DIGlobalVariable *N, SmallVectorImpl<uint64_t> &Record,
1779     unsigned Abbrev) {
1780   const uint64_t Version = 2 << 1;
1781   Record.push_back((uint64_t)N->isDistinct() | Version);
1782   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1783   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1784   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1785   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1786   Record.push_back(N->getLine());
1787   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1788   Record.push_back(N->isLocalToUnit());
1789   Record.push_back(N->isDefinition());
1790   Record.push_back(VE.getMetadataOrNullID(N->getStaticDataMemberDeclaration()));
1791   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams()));
1792   Record.push_back(N->getAlignInBits());
1793 
1794   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR, Record, Abbrev);
1795   Record.clear();
1796 }
1797 
1798 void ModuleBitcodeWriter::writeDILocalVariable(
1799     const DILocalVariable *N, SmallVectorImpl<uint64_t> &Record,
1800     unsigned Abbrev) {
1801   // In order to support all possible bitcode formats in BitcodeReader we need
1802   // to distinguish the following cases:
1803   // 1) Record has no artificial tag (Record[1]),
1804   //   has no obsolete inlinedAt field (Record[9]).
1805   //   In this case Record size will be 8, HasAlignment flag is false.
1806   // 2) Record has artificial tag (Record[1]),
1807   //   has no obsolete inlignedAt field (Record[9]).
1808   //   In this case Record size will be 9, HasAlignment flag is false.
1809   // 3) Record has both artificial tag (Record[1]) and
1810   //   obsolete inlignedAt field (Record[9]).
1811   //   In this case Record size will be 10, HasAlignment flag is false.
1812   // 4) Record has neither artificial tag, nor inlignedAt field, but
1813   //   HasAlignment flag is true and Record[8] contains alignment value.
1814   const uint64_t HasAlignmentFlag = 1 << 1;
1815   Record.push_back((uint64_t)N->isDistinct() | HasAlignmentFlag);
1816   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1817   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1818   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1819   Record.push_back(N->getLine());
1820   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1821   Record.push_back(N->getArg());
1822   Record.push_back(N->getFlags());
1823   Record.push_back(N->getAlignInBits());
1824 
1825   Stream.EmitRecord(bitc::METADATA_LOCAL_VAR, Record, Abbrev);
1826   Record.clear();
1827 }
1828 
1829 void ModuleBitcodeWriter::writeDILabel(
1830     const DILabel *N, SmallVectorImpl<uint64_t> &Record,
1831     unsigned Abbrev) {
1832   Record.push_back((uint64_t)N->isDistinct());
1833   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1834   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1835   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1836   Record.push_back(N->getLine());
1837 
1838   Stream.EmitRecord(bitc::METADATA_LABEL, Record, Abbrev);
1839   Record.clear();
1840 }
1841 
1842 void ModuleBitcodeWriter::writeDIExpression(const DIExpression *N,
1843                                             SmallVectorImpl<uint64_t> &Record,
1844                                             unsigned Abbrev) {
1845   Record.reserve(N->getElements().size() + 1);
1846   const uint64_t Version = 3 << 1;
1847   Record.push_back((uint64_t)N->isDistinct() | Version);
1848   Record.append(N->elements_begin(), N->elements_end());
1849 
1850   Stream.EmitRecord(bitc::METADATA_EXPRESSION, Record, Abbrev);
1851   Record.clear();
1852 }
1853 
1854 void ModuleBitcodeWriter::writeDIGlobalVariableExpression(
1855     const DIGlobalVariableExpression *N, SmallVectorImpl<uint64_t> &Record,
1856     unsigned Abbrev) {
1857   Record.push_back(N->isDistinct());
1858   Record.push_back(VE.getMetadataOrNullID(N->getVariable()));
1859   Record.push_back(VE.getMetadataOrNullID(N->getExpression()));
1860 
1861   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR_EXPR, Record, Abbrev);
1862   Record.clear();
1863 }
1864 
1865 void ModuleBitcodeWriter::writeDIObjCProperty(const DIObjCProperty *N,
1866                                               SmallVectorImpl<uint64_t> &Record,
1867                                               unsigned Abbrev) {
1868   Record.push_back(N->isDistinct());
1869   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1870   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1871   Record.push_back(N->getLine());
1872   Record.push_back(VE.getMetadataOrNullID(N->getRawSetterName()));
1873   Record.push_back(VE.getMetadataOrNullID(N->getRawGetterName()));
1874   Record.push_back(N->getAttributes());
1875   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1876 
1877   Stream.EmitRecord(bitc::METADATA_OBJC_PROPERTY, Record, Abbrev);
1878   Record.clear();
1879 }
1880 
1881 void ModuleBitcodeWriter::writeDIImportedEntity(
1882     const DIImportedEntity *N, SmallVectorImpl<uint64_t> &Record,
1883     unsigned Abbrev) {
1884   Record.push_back(N->isDistinct());
1885   Record.push_back(N->getTag());
1886   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1887   Record.push_back(VE.getMetadataOrNullID(N->getEntity()));
1888   Record.push_back(N->getLine());
1889   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1890   Record.push_back(VE.getMetadataOrNullID(N->getRawFile()));
1891 
1892   Stream.EmitRecord(bitc::METADATA_IMPORTED_ENTITY, Record, Abbrev);
1893   Record.clear();
1894 }
1895 
1896 unsigned ModuleBitcodeWriter::createNamedMetadataAbbrev() {
1897   auto Abbv = std::make_shared<BitCodeAbbrev>();
1898   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
1899   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1900   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1901   return Stream.EmitAbbrev(std::move(Abbv));
1902 }
1903 
1904 void ModuleBitcodeWriter::writeNamedMetadata(
1905     SmallVectorImpl<uint64_t> &Record) {
1906   if (M.named_metadata_empty())
1907     return;
1908 
1909   unsigned Abbrev = createNamedMetadataAbbrev();
1910   for (const NamedMDNode &NMD : M.named_metadata()) {
1911     // Write name.
1912     StringRef Str = NMD.getName();
1913     Record.append(Str.bytes_begin(), Str.bytes_end());
1914     Stream.EmitRecord(bitc::METADATA_NAME, Record, Abbrev);
1915     Record.clear();
1916 
1917     // Write named metadata operands.
1918     for (const MDNode *N : NMD.operands())
1919       Record.push_back(VE.getMetadataID(N));
1920     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
1921     Record.clear();
1922   }
1923 }
1924 
1925 unsigned ModuleBitcodeWriter::createMetadataStringsAbbrev() {
1926   auto Abbv = std::make_shared<BitCodeAbbrev>();
1927   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRINGS));
1928   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // # of strings
1929   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // offset to chars
1930   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
1931   return Stream.EmitAbbrev(std::move(Abbv));
1932 }
1933 
1934 /// Write out a record for MDString.
1935 ///
1936 /// All the metadata strings in a metadata block are emitted in a single
1937 /// record.  The sizes and strings themselves are shoved into a blob.
1938 void ModuleBitcodeWriter::writeMetadataStrings(
1939     ArrayRef<const Metadata *> Strings, SmallVectorImpl<uint64_t> &Record) {
1940   if (Strings.empty())
1941     return;
1942 
1943   // Start the record with the number of strings.
1944   Record.push_back(bitc::METADATA_STRINGS);
1945   Record.push_back(Strings.size());
1946 
1947   // Emit the sizes of the strings in the blob.
1948   SmallString<256> Blob;
1949   {
1950     BitstreamWriter W(Blob);
1951     for (const Metadata *MD : Strings)
1952       W.EmitVBR(cast<MDString>(MD)->getLength(), 6);
1953     W.FlushToWord();
1954   }
1955 
1956   // Add the offset to the strings to the record.
1957   Record.push_back(Blob.size());
1958 
1959   // Add the strings to the blob.
1960   for (const Metadata *MD : Strings)
1961     Blob.append(cast<MDString>(MD)->getString());
1962 
1963   // Emit the final record.
1964   Stream.EmitRecordWithBlob(createMetadataStringsAbbrev(), Record, Blob);
1965   Record.clear();
1966 }
1967 
1968 // Generates an enum to use as an index in the Abbrev array of Metadata record.
1969 enum MetadataAbbrev : unsigned {
1970 #define HANDLE_MDNODE_LEAF(CLASS) CLASS##AbbrevID,
1971 #include "llvm/IR/Metadata.def"
1972   LastPlusOne
1973 };
1974 
1975 void ModuleBitcodeWriter::writeMetadataRecords(
1976     ArrayRef<const Metadata *> MDs, SmallVectorImpl<uint64_t> &Record,
1977     std::vector<unsigned> *MDAbbrevs, std::vector<uint64_t> *IndexPos) {
1978   if (MDs.empty())
1979     return;
1980 
1981   // Initialize MDNode abbreviations.
1982 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
1983 #include "llvm/IR/Metadata.def"
1984 
1985   for (const Metadata *MD : MDs) {
1986     if (IndexPos)
1987       IndexPos->push_back(Stream.GetCurrentBitNo());
1988     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
1989       assert(N->isResolved() && "Expected forward references to be resolved");
1990 
1991       switch (N->getMetadataID()) {
1992       default:
1993         llvm_unreachable("Invalid MDNode subclass");
1994 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
1995   case Metadata::CLASS##Kind:                                                  \
1996     if (MDAbbrevs)                                                             \
1997       write##CLASS(cast<CLASS>(N), Record,                                     \
1998                    (*MDAbbrevs)[MetadataAbbrev::CLASS##AbbrevID]);             \
1999     else                                                                       \
2000       write##CLASS(cast<CLASS>(N), Record, CLASS##Abbrev);                     \
2001     continue;
2002 #include "llvm/IR/Metadata.def"
2003       }
2004     }
2005     writeValueAsMetadata(cast<ValueAsMetadata>(MD), Record);
2006   }
2007 }
2008 
2009 void ModuleBitcodeWriter::writeModuleMetadata() {
2010   if (!VE.hasMDs() && M.named_metadata_empty())
2011     return;
2012 
2013   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 4);
2014   SmallVector<uint64_t, 64> Record;
2015 
2016   // Emit all abbrevs upfront, so that the reader can jump in the middle of the
2017   // block and load any metadata.
2018   std::vector<unsigned> MDAbbrevs;
2019 
2020   MDAbbrevs.resize(MetadataAbbrev::LastPlusOne);
2021   MDAbbrevs[MetadataAbbrev::DILocationAbbrevID] = createDILocationAbbrev();
2022   MDAbbrevs[MetadataAbbrev::GenericDINodeAbbrevID] =
2023       createGenericDINodeAbbrev();
2024 
2025   auto Abbv = std::make_shared<BitCodeAbbrev>();
2026   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX_OFFSET));
2027   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2028   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2029   unsigned OffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2030 
2031   Abbv = std::make_shared<BitCodeAbbrev>();
2032   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX));
2033   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2034   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2035   unsigned IndexAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2036 
2037   // Emit MDStrings together upfront.
2038   writeMetadataStrings(VE.getMDStrings(), Record);
2039 
2040   // We only emit an index for the metadata record if we have more than a given
2041   // (naive) threshold of metadatas, otherwise it is not worth it.
2042   if (VE.getNonMDStrings().size() > IndexThreshold) {
2043     // Write a placeholder value in for the offset of the metadata index,
2044     // which is written after the records, so that it can include
2045     // the offset of each entry. The placeholder offset will be
2046     // updated after all records are emitted.
2047     uint64_t Vals[] = {0, 0};
2048     Stream.EmitRecord(bitc::METADATA_INDEX_OFFSET, Vals, OffsetAbbrev);
2049   }
2050 
2051   // Compute and save the bit offset to the current position, which will be
2052   // patched when we emit the index later. We can simply subtract the 64-bit
2053   // fixed size from the current bit number to get the location to backpatch.
2054   uint64_t IndexOffsetRecordBitPos = Stream.GetCurrentBitNo();
2055 
2056   // This index will contain the bitpos for each individual record.
2057   std::vector<uint64_t> IndexPos;
2058   IndexPos.reserve(VE.getNonMDStrings().size());
2059 
2060   // Write all the records
2061   writeMetadataRecords(VE.getNonMDStrings(), Record, &MDAbbrevs, &IndexPos);
2062 
2063   if (VE.getNonMDStrings().size() > IndexThreshold) {
2064     // Now that we have emitted all the records we will emit the index. But
2065     // first
2066     // backpatch the forward reference so that the reader can skip the records
2067     // efficiently.
2068     Stream.BackpatchWord64(IndexOffsetRecordBitPos - 64,
2069                            Stream.GetCurrentBitNo() - IndexOffsetRecordBitPos);
2070 
2071     // Delta encode the index.
2072     uint64_t PreviousValue = IndexOffsetRecordBitPos;
2073     for (auto &Elt : IndexPos) {
2074       auto EltDelta = Elt - PreviousValue;
2075       PreviousValue = Elt;
2076       Elt = EltDelta;
2077     }
2078     // Emit the index record.
2079     Stream.EmitRecord(bitc::METADATA_INDEX, IndexPos, IndexAbbrev);
2080     IndexPos.clear();
2081   }
2082 
2083   // Write the named metadata now.
2084   writeNamedMetadata(Record);
2085 
2086   auto AddDeclAttachedMetadata = [&](const GlobalObject &GO) {
2087     SmallVector<uint64_t, 4> Record;
2088     Record.push_back(VE.getValueID(&GO));
2089     pushGlobalMetadataAttachment(Record, GO);
2090     Stream.EmitRecord(bitc::METADATA_GLOBAL_DECL_ATTACHMENT, Record);
2091   };
2092   for (const Function &F : M)
2093     if (F.isDeclaration() && F.hasMetadata())
2094       AddDeclAttachedMetadata(F);
2095   // FIXME: Only store metadata for declarations here, and move data for global
2096   // variable definitions to a separate block (PR28134).
2097   for (const GlobalVariable &GV : M.globals())
2098     if (GV.hasMetadata())
2099       AddDeclAttachedMetadata(GV);
2100 
2101   Stream.ExitBlock();
2102 }
2103 
2104 void ModuleBitcodeWriter::writeFunctionMetadata(const Function &F) {
2105   if (!VE.hasMDs())
2106     return;
2107 
2108   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
2109   SmallVector<uint64_t, 64> Record;
2110   writeMetadataStrings(VE.getMDStrings(), Record);
2111   writeMetadataRecords(VE.getNonMDStrings(), Record);
2112   Stream.ExitBlock();
2113 }
2114 
2115 void ModuleBitcodeWriter::pushGlobalMetadataAttachment(
2116     SmallVectorImpl<uint64_t> &Record, const GlobalObject &GO) {
2117   // [n x [id, mdnode]]
2118   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2119   GO.getAllMetadata(MDs);
2120   for (const auto &I : MDs) {
2121     Record.push_back(I.first);
2122     Record.push_back(VE.getMetadataID(I.second));
2123   }
2124 }
2125 
2126 void ModuleBitcodeWriter::writeFunctionMetadataAttachment(const Function &F) {
2127   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
2128 
2129   SmallVector<uint64_t, 64> Record;
2130 
2131   if (F.hasMetadata()) {
2132     pushGlobalMetadataAttachment(Record, F);
2133     Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2134     Record.clear();
2135   }
2136 
2137   // Write metadata attachments
2138   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
2139   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2140   for (const BasicBlock &BB : F)
2141     for (const Instruction &I : BB) {
2142       MDs.clear();
2143       I.getAllMetadataOtherThanDebugLoc(MDs);
2144 
2145       // If no metadata, ignore instruction.
2146       if (MDs.empty()) continue;
2147 
2148       Record.push_back(VE.getInstructionID(&I));
2149 
2150       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
2151         Record.push_back(MDs[i].first);
2152         Record.push_back(VE.getMetadataID(MDs[i].second));
2153       }
2154       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2155       Record.clear();
2156     }
2157 
2158   Stream.ExitBlock();
2159 }
2160 
2161 void ModuleBitcodeWriter::writeModuleMetadataKinds() {
2162   SmallVector<uint64_t, 64> Record;
2163 
2164   // Write metadata kinds
2165   // METADATA_KIND - [n x [id, name]]
2166   SmallVector<StringRef, 8> Names;
2167   M.getMDKindNames(Names);
2168 
2169   if (Names.empty()) return;
2170 
2171   Stream.EnterSubblock(bitc::METADATA_KIND_BLOCK_ID, 3);
2172 
2173   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
2174     Record.push_back(MDKindID);
2175     StringRef KName = Names[MDKindID];
2176     Record.append(KName.begin(), KName.end());
2177 
2178     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
2179     Record.clear();
2180   }
2181 
2182   Stream.ExitBlock();
2183 }
2184 
2185 void ModuleBitcodeWriter::writeOperandBundleTags() {
2186   // Write metadata kinds
2187   //
2188   // OPERAND_BUNDLE_TAGS_BLOCK_ID : N x OPERAND_BUNDLE_TAG
2189   //
2190   // OPERAND_BUNDLE_TAG - [strchr x N]
2191 
2192   SmallVector<StringRef, 8> Tags;
2193   M.getOperandBundleTags(Tags);
2194 
2195   if (Tags.empty())
2196     return;
2197 
2198   Stream.EnterSubblock(bitc::OPERAND_BUNDLE_TAGS_BLOCK_ID, 3);
2199 
2200   SmallVector<uint64_t, 64> Record;
2201 
2202   for (auto Tag : Tags) {
2203     Record.append(Tag.begin(), Tag.end());
2204 
2205     Stream.EmitRecord(bitc::OPERAND_BUNDLE_TAG, Record, 0);
2206     Record.clear();
2207   }
2208 
2209   Stream.ExitBlock();
2210 }
2211 
2212 void ModuleBitcodeWriter::writeSyncScopeNames() {
2213   SmallVector<StringRef, 8> SSNs;
2214   M.getContext().getSyncScopeNames(SSNs);
2215   if (SSNs.empty())
2216     return;
2217 
2218   Stream.EnterSubblock(bitc::SYNC_SCOPE_NAMES_BLOCK_ID, 2);
2219 
2220   SmallVector<uint64_t, 64> Record;
2221   for (auto SSN : SSNs) {
2222     Record.append(SSN.begin(), SSN.end());
2223     Stream.EmitRecord(bitc::SYNC_SCOPE_NAME, Record, 0);
2224     Record.clear();
2225   }
2226 
2227   Stream.ExitBlock();
2228 }
2229 
2230 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
2231   if ((int64_t)V >= 0)
2232     Vals.push_back(V << 1);
2233   else
2234     Vals.push_back((-V << 1) | 1);
2235 }
2236 
2237 void ModuleBitcodeWriter::writeConstants(unsigned FirstVal, unsigned LastVal,
2238                                          bool isGlobal) {
2239   if (FirstVal == LastVal) return;
2240 
2241   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
2242 
2243   unsigned AggregateAbbrev = 0;
2244   unsigned String8Abbrev = 0;
2245   unsigned CString7Abbrev = 0;
2246   unsigned CString6Abbrev = 0;
2247   // If this is a constant pool for the module, emit module-specific abbrevs.
2248   if (isGlobal) {
2249     // Abbrev for CST_CODE_AGGREGATE.
2250     auto Abbv = std::make_shared<BitCodeAbbrev>();
2251     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
2252     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2253     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
2254     AggregateAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2255 
2256     // Abbrev for CST_CODE_STRING.
2257     Abbv = std::make_shared<BitCodeAbbrev>();
2258     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
2259     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2260     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2261     String8Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2262     // Abbrev for CST_CODE_CSTRING.
2263     Abbv = std::make_shared<BitCodeAbbrev>();
2264     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2265     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2266     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2267     CString7Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2268     // Abbrev for CST_CODE_CSTRING.
2269     Abbv = std::make_shared<BitCodeAbbrev>();
2270     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2271     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2272     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2273     CString6Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2274   }
2275 
2276   SmallVector<uint64_t, 64> Record;
2277 
2278   const ValueEnumerator::ValueList &Vals = VE.getValues();
2279   Type *LastTy = nullptr;
2280   for (unsigned i = FirstVal; i != LastVal; ++i) {
2281     const Value *V = Vals[i].first;
2282     // If we need to switch types, do so now.
2283     if (V->getType() != LastTy) {
2284       LastTy = V->getType();
2285       Record.push_back(VE.getTypeID(LastTy));
2286       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
2287                         CONSTANTS_SETTYPE_ABBREV);
2288       Record.clear();
2289     }
2290 
2291     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
2292       Record.push_back(unsigned(IA->hasSideEffects()) |
2293                        unsigned(IA->isAlignStack()) << 1 |
2294                        unsigned(IA->getDialect()&1) << 2);
2295 
2296       // Add the asm string.
2297       const std::string &AsmStr = IA->getAsmString();
2298       Record.push_back(AsmStr.size());
2299       Record.append(AsmStr.begin(), AsmStr.end());
2300 
2301       // Add the constraint string.
2302       const std::string &ConstraintStr = IA->getConstraintString();
2303       Record.push_back(ConstraintStr.size());
2304       Record.append(ConstraintStr.begin(), ConstraintStr.end());
2305       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
2306       Record.clear();
2307       continue;
2308     }
2309     const Constant *C = cast<Constant>(V);
2310     unsigned Code = -1U;
2311     unsigned AbbrevToUse = 0;
2312     if (C->isNullValue()) {
2313       Code = bitc::CST_CODE_NULL;
2314     } else if (isa<UndefValue>(C)) {
2315       Code = bitc::CST_CODE_UNDEF;
2316     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
2317       if (IV->getBitWidth() <= 64) {
2318         uint64_t V = IV->getSExtValue();
2319         emitSignedInt64(Record, V);
2320         Code = bitc::CST_CODE_INTEGER;
2321         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
2322       } else {                             // Wide integers, > 64 bits in size.
2323         // We have an arbitrary precision integer value to write whose
2324         // bit width is > 64. However, in canonical unsigned integer
2325         // format it is likely that the high bits are going to be zero.
2326         // So, we only write the number of active words.
2327         unsigned NWords = IV->getValue().getActiveWords();
2328         const uint64_t *RawWords = IV->getValue().getRawData();
2329         for (unsigned i = 0; i != NWords; ++i) {
2330           emitSignedInt64(Record, RawWords[i]);
2331         }
2332         Code = bitc::CST_CODE_WIDE_INTEGER;
2333       }
2334     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
2335       Code = bitc::CST_CODE_FLOAT;
2336       Type *Ty = CFP->getType();
2337       if (Ty->isHalfTy() || Ty->isFloatTy() || Ty->isDoubleTy()) {
2338         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
2339       } else if (Ty->isX86_FP80Ty()) {
2340         // api needed to prevent premature destruction
2341         // bits are not in the same order as a normal i80 APInt, compensate.
2342         APInt api = CFP->getValueAPF().bitcastToAPInt();
2343         const uint64_t *p = api.getRawData();
2344         Record.push_back((p[1] << 48) | (p[0] >> 16));
2345         Record.push_back(p[0] & 0xffffLL);
2346       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
2347         APInt api = CFP->getValueAPF().bitcastToAPInt();
2348         const uint64_t *p = api.getRawData();
2349         Record.push_back(p[0]);
2350         Record.push_back(p[1]);
2351       } else {
2352         assert(0 && "Unknown FP type!");
2353       }
2354     } else if (isa<ConstantDataSequential>(C) &&
2355                cast<ConstantDataSequential>(C)->isString()) {
2356       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
2357       // Emit constant strings specially.
2358       unsigned NumElts = Str->getNumElements();
2359       // If this is a null-terminated string, use the denser CSTRING encoding.
2360       if (Str->isCString()) {
2361         Code = bitc::CST_CODE_CSTRING;
2362         --NumElts;  // Don't encode the null, which isn't allowed by char6.
2363       } else {
2364         Code = bitc::CST_CODE_STRING;
2365         AbbrevToUse = String8Abbrev;
2366       }
2367       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
2368       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
2369       for (unsigned i = 0; i != NumElts; ++i) {
2370         unsigned char V = Str->getElementAsInteger(i);
2371         Record.push_back(V);
2372         isCStr7 &= (V & 128) == 0;
2373         if (isCStrChar6)
2374           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
2375       }
2376 
2377       if (isCStrChar6)
2378         AbbrevToUse = CString6Abbrev;
2379       else if (isCStr7)
2380         AbbrevToUse = CString7Abbrev;
2381     } else if (const ConstantDataSequential *CDS =
2382                   dyn_cast<ConstantDataSequential>(C)) {
2383       Code = bitc::CST_CODE_DATA;
2384       Type *EltTy = CDS->getType()->getElementType();
2385       if (isa<IntegerType>(EltTy)) {
2386         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2387           Record.push_back(CDS->getElementAsInteger(i));
2388       } else {
2389         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2390           Record.push_back(
2391               CDS->getElementAsAPFloat(i).bitcastToAPInt().getLimitedValue());
2392       }
2393     } else if (isa<ConstantAggregate>(C)) {
2394       Code = bitc::CST_CODE_AGGREGATE;
2395       for (const Value *Op : C->operands())
2396         Record.push_back(VE.getValueID(Op));
2397       AbbrevToUse = AggregateAbbrev;
2398     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
2399       switch (CE->getOpcode()) {
2400       default:
2401         if (Instruction::isCast(CE->getOpcode())) {
2402           Code = bitc::CST_CODE_CE_CAST;
2403           Record.push_back(getEncodedCastOpcode(CE->getOpcode()));
2404           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2405           Record.push_back(VE.getValueID(C->getOperand(0)));
2406           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
2407         } else {
2408           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
2409           Code = bitc::CST_CODE_CE_BINOP;
2410           Record.push_back(getEncodedBinaryOpcode(CE->getOpcode()));
2411           Record.push_back(VE.getValueID(C->getOperand(0)));
2412           Record.push_back(VE.getValueID(C->getOperand(1)));
2413           uint64_t Flags = getOptimizationFlags(CE);
2414           if (Flags != 0)
2415             Record.push_back(Flags);
2416         }
2417         break;
2418       case Instruction::FNeg: {
2419         assert(CE->getNumOperands() == 1 && "Unknown constant expr!");
2420         Code = bitc::CST_CODE_CE_UNOP;
2421         Record.push_back(getEncodedUnaryOpcode(CE->getOpcode()));
2422         Record.push_back(VE.getValueID(C->getOperand(0)));
2423         uint64_t Flags = getOptimizationFlags(CE);
2424         if (Flags != 0)
2425           Record.push_back(Flags);
2426         break;
2427       }
2428       case Instruction::GetElementPtr: {
2429         Code = bitc::CST_CODE_CE_GEP;
2430         const auto *GO = cast<GEPOperator>(C);
2431         Record.push_back(VE.getTypeID(GO->getSourceElementType()));
2432         if (Optional<unsigned> Idx = GO->getInRangeIndex()) {
2433           Code = bitc::CST_CODE_CE_GEP_WITH_INRANGE_INDEX;
2434           Record.push_back((*Idx << 1) | GO->isInBounds());
2435         } else if (GO->isInBounds())
2436           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
2437         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
2438           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
2439           Record.push_back(VE.getValueID(C->getOperand(i)));
2440         }
2441         break;
2442       }
2443       case Instruction::Select:
2444         Code = bitc::CST_CODE_CE_SELECT;
2445         Record.push_back(VE.getValueID(C->getOperand(0)));
2446         Record.push_back(VE.getValueID(C->getOperand(1)));
2447         Record.push_back(VE.getValueID(C->getOperand(2)));
2448         break;
2449       case Instruction::ExtractElement:
2450         Code = bitc::CST_CODE_CE_EXTRACTELT;
2451         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2452         Record.push_back(VE.getValueID(C->getOperand(0)));
2453         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
2454         Record.push_back(VE.getValueID(C->getOperand(1)));
2455         break;
2456       case Instruction::InsertElement:
2457         Code = bitc::CST_CODE_CE_INSERTELT;
2458         Record.push_back(VE.getValueID(C->getOperand(0)));
2459         Record.push_back(VE.getValueID(C->getOperand(1)));
2460         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
2461         Record.push_back(VE.getValueID(C->getOperand(2)));
2462         break;
2463       case Instruction::ShuffleVector:
2464         // If the return type and argument types are the same, this is a
2465         // standard shufflevector instruction.  If the types are different,
2466         // then the shuffle is widening or truncating the input vectors, and
2467         // the argument type must also be encoded.
2468         if (C->getType() == C->getOperand(0)->getType()) {
2469           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
2470         } else {
2471           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
2472           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2473         }
2474         Record.push_back(VE.getValueID(C->getOperand(0)));
2475         Record.push_back(VE.getValueID(C->getOperand(1)));
2476         Record.push_back(VE.getValueID(C->getOperand(2)));
2477         break;
2478       case Instruction::ICmp:
2479       case Instruction::FCmp:
2480         Code = bitc::CST_CODE_CE_CMP;
2481         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2482         Record.push_back(VE.getValueID(C->getOperand(0)));
2483         Record.push_back(VE.getValueID(C->getOperand(1)));
2484         Record.push_back(CE->getPredicate());
2485         break;
2486       }
2487     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
2488       Code = bitc::CST_CODE_BLOCKADDRESS;
2489       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
2490       Record.push_back(VE.getValueID(BA->getFunction()));
2491       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
2492     } else {
2493 #ifndef NDEBUG
2494       C->dump();
2495 #endif
2496       llvm_unreachable("Unknown constant!");
2497     }
2498     Stream.EmitRecord(Code, Record, AbbrevToUse);
2499     Record.clear();
2500   }
2501 
2502   Stream.ExitBlock();
2503 }
2504 
2505 void ModuleBitcodeWriter::writeModuleConstants() {
2506   const ValueEnumerator::ValueList &Vals = VE.getValues();
2507 
2508   // Find the first constant to emit, which is the first non-globalvalue value.
2509   // We know globalvalues have been emitted by WriteModuleInfo.
2510   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
2511     if (!isa<GlobalValue>(Vals[i].first)) {
2512       writeConstants(i, Vals.size(), true);
2513       return;
2514     }
2515   }
2516 }
2517 
2518 /// pushValueAndType - The file has to encode both the value and type id for
2519 /// many values, because we need to know what type to create for forward
2520 /// references.  However, most operands are not forward references, so this type
2521 /// field is not needed.
2522 ///
2523 /// This function adds V's value ID to Vals.  If the value ID is higher than the
2524 /// instruction ID, then it is a forward reference, and it also includes the
2525 /// type ID.  The value ID that is written is encoded relative to the InstID.
2526 bool ModuleBitcodeWriter::pushValueAndType(const Value *V, unsigned InstID,
2527                                            SmallVectorImpl<unsigned> &Vals) {
2528   unsigned ValID = VE.getValueID(V);
2529   // Make encoding relative to the InstID.
2530   Vals.push_back(InstID - ValID);
2531   if (ValID >= InstID) {
2532     Vals.push_back(VE.getTypeID(V->getType()));
2533     return true;
2534   }
2535   return false;
2536 }
2537 
2538 void ModuleBitcodeWriter::writeOperandBundles(ImmutableCallSite CS,
2539                                               unsigned InstID) {
2540   SmallVector<unsigned, 64> Record;
2541   LLVMContext &C = CS.getInstruction()->getContext();
2542 
2543   for (unsigned i = 0, e = CS.getNumOperandBundles(); i != e; ++i) {
2544     const auto &Bundle = CS.getOperandBundleAt(i);
2545     Record.push_back(C.getOperandBundleTagID(Bundle.getTagName()));
2546 
2547     for (auto &Input : Bundle.Inputs)
2548       pushValueAndType(Input, InstID, Record);
2549 
2550     Stream.EmitRecord(bitc::FUNC_CODE_OPERAND_BUNDLE, Record);
2551     Record.clear();
2552   }
2553 }
2554 
2555 /// pushValue - Like pushValueAndType, but where the type of the value is
2556 /// omitted (perhaps it was already encoded in an earlier operand).
2557 void ModuleBitcodeWriter::pushValue(const Value *V, unsigned InstID,
2558                                     SmallVectorImpl<unsigned> &Vals) {
2559   unsigned ValID = VE.getValueID(V);
2560   Vals.push_back(InstID - ValID);
2561 }
2562 
2563 void ModuleBitcodeWriter::pushValueSigned(const Value *V, unsigned InstID,
2564                                           SmallVectorImpl<uint64_t> &Vals) {
2565   unsigned ValID = VE.getValueID(V);
2566   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
2567   emitSignedInt64(Vals, diff);
2568 }
2569 
2570 /// WriteInstruction - Emit an instruction to the specified stream.
2571 void ModuleBitcodeWriter::writeInstruction(const Instruction &I,
2572                                            unsigned InstID,
2573                                            SmallVectorImpl<unsigned> &Vals) {
2574   unsigned Code = 0;
2575   unsigned AbbrevToUse = 0;
2576   VE.setInstructionID(&I);
2577   switch (I.getOpcode()) {
2578   default:
2579     if (Instruction::isCast(I.getOpcode())) {
2580       Code = bitc::FUNC_CODE_INST_CAST;
2581       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2582         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
2583       Vals.push_back(VE.getTypeID(I.getType()));
2584       Vals.push_back(getEncodedCastOpcode(I.getOpcode()));
2585     } else {
2586       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
2587       Code = bitc::FUNC_CODE_INST_BINOP;
2588       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2589         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
2590       pushValue(I.getOperand(1), InstID, Vals);
2591       Vals.push_back(getEncodedBinaryOpcode(I.getOpcode()));
2592       uint64_t Flags = getOptimizationFlags(&I);
2593       if (Flags != 0) {
2594         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
2595           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
2596         Vals.push_back(Flags);
2597       }
2598     }
2599     break;
2600   case Instruction::FNeg: {
2601     Code = bitc::FUNC_CODE_INST_UNOP;
2602     if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2603       AbbrevToUse = FUNCTION_INST_UNOP_ABBREV;
2604     Vals.push_back(getEncodedUnaryOpcode(I.getOpcode()));
2605     uint64_t Flags = getOptimizationFlags(&I);
2606     if (Flags != 0) {
2607       if (AbbrevToUse == FUNCTION_INST_UNOP_ABBREV)
2608         AbbrevToUse = FUNCTION_INST_UNOP_FLAGS_ABBREV;
2609       Vals.push_back(Flags);
2610     }
2611     break;
2612   }
2613   case Instruction::GetElementPtr: {
2614     Code = bitc::FUNC_CODE_INST_GEP;
2615     AbbrevToUse = FUNCTION_INST_GEP_ABBREV;
2616     auto &GEPInst = cast<GetElementPtrInst>(I);
2617     Vals.push_back(GEPInst.isInBounds());
2618     Vals.push_back(VE.getTypeID(GEPInst.getSourceElementType()));
2619     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
2620       pushValueAndType(I.getOperand(i), InstID, Vals);
2621     break;
2622   }
2623   case Instruction::ExtractValue: {
2624     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
2625     pushValueAndType(I.getOperand(0), InstID, Vals);
2626     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
2627     Vals.append(EVI->idx_begin(), EVI->idx_end());
2628     break;
2629   }
2630   case Instruction::InsertValue: {
2631     Code = bitc::FUNC_CODE_INST_INSERTVAL;
2632     pushValueAndType(I.getOperand(0), InstID, Vals);
2633     pushValueAndType(I.getOperand(1), InstID, Vals);
2634     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
2635     Vals.append(IVI->idx_begin(), IVI->idx_end());
2636     break;
2637   }
2638   case Instruction::Select:
2639     Code = bitc::FUNC_CODE_INST_VSELECT;
2640     pushValueAndType(I.getOperand(1), InstID, Vals);
2641     pushValue(I.getOperand(2), InstID, Vals);
2642     pushValueAndType(I.getOperand(0), InstID, Vals);
2643     break;
2644   case Instruction::ExtractElement:
2645     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
2646     pushValueAndType(I.getOperand(0), InstID, Vals);
2647     pushValueAndType(I.getOperand(1), InstID, Vals);
2648     break;
2649   case Instruction::InsertElement:
2650     Code = bitc::FUNC_CODE_INST_INSERTELT;
2651     pushValueAndType(I.getOperand(0), InstID, Vals);
2652     pushValue(I.getOperand(1), InstID, Vals);
2653     pushValueAndType(I.getOperand(2), InstID, Vals);
2654     break;
2655   case Instruction::ShuffleVector:
2656     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
2657     pushValueAndType(I.getOperand(0), InstID, Vals);
2658     pushValue(I.getOperand(1), InstID, Vals);
2659     pushValue(I.getOperand(2), InstID, Vals);
2660     break;
2661   case Instruction::ICmp:
2662   case Instruction::FCmp: {
2663     // compare returning Int1Ty or vector of Int1Ty
2664     Code = bitc::FUNC_CODE_INST_CMP2;
2665     pushValueAndType(I.getOperand(0), InstID, Vals);
2666     pushValue(I.getOperand(1), InstID, Vals);
2667     Vals.push_back(cast<CmpInst>(I).getPredicate());
2668     uint64_t Flags = getOptimizationFlags(&I);
2669     if (Flags != 0)
2670       Vals.push_back(Flags);
2671     break;
2672   }
2673 
2674   case Instruction::Ret:
2675     {
2676       Code = bitc::FUNC_CODE_INST_RET;
2677       unsigned NumOperands = I.getNumOperands();
2678       if (NumOperands == 0)
2679         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
2680       else if (NumOperands == 1) {
2681         if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2682           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
2683       } else {
2684         for (unsigned i = 0, e = NumOperands; i != e; ++i)
2685           pushValueAndType(I.getOperand(i), InstID, Vals);
2686       }
2687     }
2688     break;
2689   case Instruction::Br:
2690     {
2691       Code = bitc::FUNC_CODE_INST_BR;
2692       const BranchInst &II = cast<BranchInst>(I);
2693       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
2694       if (II.isConditional()) {
2695         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
2696         pushValue(II.getCondition(), InstID, Vals);
2697       }
2698     }
2699     break;
2700   case Instruction::Switch:
2701     {
2702       Code = bitc::FUNC_CODE_INST_SWITCH;
2703       const SwitchInst &SI = cast<SwitchInst>(I);
2704       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
2705       pushValue(SI.getCondition(), InstID, Vals);
2706       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
2707       for (auto Case : SI.cases()) {
2708         Vals.push_back(VE.getValueID(Case.getCaseValue()));
2709         Vals.push_back(VE.getValueID(Case.getCaseSuccessor()));
2710       }
2711     }
2712     break;
2713   case Instruction::IndirectBr:
2714     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
2715     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2716     // Encode the address operand as relative, but not the basic blocks.
2717     pushValue(I.getOperand(0), InstID, Vals);
2718     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
2719       Vals.push_back(VE.getValueID(I.getOperand(i)));
2720     break;
2721 
2722   case Instruction::Invoke: {
2723     const InvokeInst *II = cast<InvokeInst>(&I);
2724     const Value *Callee = II->getCalledValue();
2725     FunctionType *FTy = II->getFunctionType();
2726 
2727     if (II->hasOperandBundles())
2728       writeOperandBundles(II, InstID);
2729 
2730     Code = bitc::FUNC_CODE_INST_INVOKE;
2731 
2732     Vals.push_back(VE.getAttributeListID(II->getAttributes()));
2733     Vals.push_back(II->getCallingConv() | 1 << 13);
2734     Vals.push_back(VE.getValueID(II->getNormalDest()));
2735     Vals.push_back(VE.getValueID(II->getUnwindDest()));
2736     Vals.push_back(VE.getTypeID(FTy));
2737     pushValueAndType(Callee, InstID, Vals);
2738 
2739     // Emit value #'s for the fixed parameters.
2740     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
2741       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
2742 
2743     // Emit type/value pairs for varargs params.
2744     if (FTy->isVarArg()) {
2745       for (unsigned i = FTy->getNumParams(), e = II->getNumArgOperands();
2746            i != e; ++i)
2747         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
2748     }
2749     break;
2750   }
2751   case Instruction::Resume:
2752     Code = bitc::FUNC_CODE_INST_RESUME;
2753     pushValueAndType(I.getOperand(0), InstID, Vals);
2754     break;
2755   case Instruction::CleanupRet: {
2756     Code = bitc::FUNC_CODE_INST_CLEANUPRET;
2757     const auto &CRI = cast<CleanupReturnInst>(I);
2758     pushValue(CRI.getCleanupPad(), InstID, Vals);
2759     if (CRI.hasUnwindDest())
2760       Vals.push_back(VE.getValueID(CRI.getUnwindDest()));
2761     break;
2762   }
2763   case Instruction::CatchRet: {
2764     Code = bitc::FUNC_CODE_INST_CATCHRET;
2765     const auto &CRI = cast<CatchReturnInst>(I);
2766     pushValue(CRI.getCatchPad(), InstID, Vals);
2767     Vals.push_back(VE.getValueID(CRI.getSuccessor()));
2768     break;
2769   }
2770   case Instruction::CleanupPad:
2771   case Instruction::CatchPad: {
2772     const auto &FuncletPad = cast<FuncletPadInst>(I);
2773     Code = isa<CatchPadInst>(FuncletPad) ? bitc::FUNC_CODE_INST_CATCHPAD
2774                                          : bitc::FUNC_CODE_INST_CLEANUPPAD;
2775     pushValue(FuncletPad.getParentPad(), InstID, Vals);
2776 
2777     unsigned NumArgOperands = FuncletPad.getNumArgOperands();
2778     Vals.push_back(NumArgOperands);
2779     for (unsigned Op = 0; Op != NumArgOperands; ++Op)
2780       pushValueAndType(FuncletPad.getArgOperand(Op), InstID, Vals);
2781     break;
2782   }
2783   case Instruction::CatchSwitch: {
2784     Code = bitc::FUNC_CODE_INST_CATCHSWITCH;
2785     const auto &CatchSwitch = cast<CatchSwitchInst>(I);
2786 
2787     pushValue(CatchSwitch.getParentPad(), InstID, Vals);
2788 
2789     unsigned NumHandlers = CatchSwitch.getNumHandlers();
2790     Vals.push_back(NumHandlers);
2791     for (const BasicBlock *CatchPadBB : CatchSwitch.handlers())
2792       Vals.push_back(VE.getValueID(CatchPadBB));
2793 
2794     if (CatchSwitch.hasUnwindDest())
2795       Vals.push_back(VE.getValueID(CatchSwitch.getUnwindDest()));
2796     break;
2797   }
2798   case Instruction::CallBr: {
2799     const CallBrInst *CBI = cast<CallBrInst>(&I);
2800     const Value *Callee = CBI->getCalledValue();
2801     FunctionType *FTy = CBI->getFunctionType();
2802 
2803     if (CBI->hasOperandBundles())
2804       writeOperandBundles(CBI, InstID);
2805 
2806     Code = bitc::FUNC_CODE_INST_CALLBR;
2807 
2808     Vals.push_back(VE.getAttributeListID(CBI->getAttributes()));
2809 
2810     Vals.push_back(CBI->getCallingConv() << bitc::CALL_CCONV |
2811                    1 << bitc::CALL_EXPLICIT_TYPE);
2812 
2813     Vals.push_back(VE.getValueID(CBI->getDefaultDest()));
2814     Vals.push_back(CBI->getNumIndirectDests());
2815     for (unsigned i = 0, e = CBI->getNumIndirectDests(); i != e; ++i)
2816       Vals.push_back(VE.getValueID(CBI->getIndirectDest(i)));
2817 
2818     Vals.push_back(VE.getTypeID(FTy));
2819     pushValueAndType(Callee, InstID, Vals);
2820 
2821     // Emit value #'s for the fixed parameters.
2822     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
2823       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
2824 
2825     // Emit type/value pairs for varargs params.
2826     if (FTy->isVarArg()) {
2827       for (unsigned i = FTy->getNumParams(), e = CBI->getNumArgOperands();
2828            i != e; ++i)
2829         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
2830     }
2831     break;
2832   }
2833   case Instruction::Unreachable:
2834     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
2835     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
2836     break;
2837 
2838   case Instruction::PHI: {
2839     const PHINode &PN = cast<PHINode>(I);
2840     Code = bitc::FUNC_CODE_INST_PHI;
2841     // With the newer instruction encoding, forward references could give
2842     // negative valued IDs.  This is most common for PHIs, so we use
2843     // signed VBRs.
2844     SmallVector<uint64_t, 128> Vals64;
2845     Vals64.push_back(VE.getTypeID(PN.getType()));
2846     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
2847       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64);
2848       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
2849     }
2850     // Emit a Vals64 vector and exit.
2851     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
2852     Vals64.clear();
2853     return;
2854   }
2855 
2856   case Instruction::LandingPad: {
2857     const LandingPadInst &LP = cast<LandingPadInst>(I);
2858     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
2859     Vals.push_back(VE.getTypeID(LP.getType()));
2860     Vals.push_back(LP.isCleanup());
2861     Vals.push_back(LP.getNumClauses());
2862     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
2863       if (LP.isCatch(I))
2864         Vals.push_back(LandingPadInst::Catch);
2865       else
2866         Vals.push_back(LandingPadInst::Filter);
2867       pushValueAndType(LP.getClause(I), InstID, Vals);
2868     }
2869     break;
2870   }
2871 
2872   case Instruction::Alloca: {
2873     Code = bitc::FUNC_CODE_INST_ALLOCA;
2874     const AllocaInst &AI = cast<AllocaInst>(I);
2875     Vals.push_back(VE.getTypeID(AI.getAllocatedType()));
2876     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2877     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
2878     unsigned AlignRecord = Log2_32(AI.getAlignment()) + 1;
2879     assert(Log2_32(Value::MaximumAlignment) + 1 < 1 << 5 &&
2880            "not enough bits for maximum alignment");
2881     assert(AlignRecord < 1 << 5 && "alignment greater than 1 << 64");
2882     AlignRecord |= AI.isUsedWithInAlloca() << 5;
2883     AlignRecord |= 1 << 6;
2884     AlignRecord |= AI.isSwiftError() << 7;
2885     Vals.push_back(AlignRecord);
2886     break;
2887   }
2888 
2889   case Instruction::Load:
2890     if (cast<LoadInst>(I).isAtomic()) {
2891       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
2892       pushValueAndType(I.getOperand(0), InstID, Vals);
2893     } else {
2894       Code = bitc::FUNC_CODE_INST_LOAD;
2895       if (!pushValueAndType(I.getOperand(0), InstID, Vals)) // ptr
2896         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
2897     }
2898     Vals.push_back(VE.getTypeID(I.getType()));
2899     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
2900     Vals.push_back(cast<LoadInst>(I).isVolatile());
2901     if (cast<LoadInst>(I).isAtomic()) {
2902       Vals.push_back(getEncodedOrdering(cast<LoadInst>(I).getOrdering()));
2903       Vals.push_back(getEncodedSyncScopeID(cast<LoadInst>(I).getSyncScopeID()));
2904     }
2905     break;
2906   case Instruction::Store:
2907     if (cast<StoreInst>(I).isAtomic())
2908       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
2909     else
2910       Code = bitc::FUNC_CODE_INST_STORE;
2911     pushValueAndType(I.getOperand(1), InstID, Vals); // ptrty + ptr
2912     pushValueAndType(I.getOperand(0), InstID, Vals); // valty + val
2913     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
2914     Vals.push_back(cast<StoreInst>(I).isVolatile());
2915     if (cast<StoreInst>(I).isAtomic()) {
2916       Vals.push_back(getEncodedOrdering(cast<StoreInst>(I).getOrdering()));
2917       Vals.push_back(
2918           getEncodedSyncScopeID(cast<StoreInst>(I).getSyncScopeID()));
2919     }
2920     break;
2921   case Instruction::AtomicCmpXchg:
2922     Code = bitc::FUNC_CODE_INST_CMPXCHG;
2923     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
2924     pushValueAndType(I.getOperand(1), InstID, Vals); // cmp.
2925     pushValue(I.getOperand(2), InstID, Vals);        // newval.
2926     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
2927     Vals.push_back(
2928         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
2929     Vals.push_back(
2930         getEncodedSyncScopeID(cast<AtomicCmpXchgInst>(I).getSyncScopeID()));
2931     Vals.push_back(
2932         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
2933     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
2934     break;
2935   case Instruction::AtomicRMW:
2936     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
2937     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
2938     pushValue(I.getOperand(1), InstID, Vals);        // val.
2939     Vals.push_back(
2940         getEncodedRMWOperation(cast<AtomicRMWInst>(I).getOperation()));
2941     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
2942     Vals.push_back(getEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
2943     Vals.push_back(
2944         getEncodedSyncScopeID(cast<AtomicRMWInst>(I).getSyncScopeID()));
2945     break;
2946   case Instruction::Fence:
2947     Code = bitc::FUNC_CODE_INST_FENCE;
2948     Vals.push_back(getEncodedOrdering(cast<FenceInst>(I).getOrdering()));
2949     Vals.push_back(getEncodedSyncScopeID(cast<FenceInst>(I).getSyncScopeID()));
2950     break;
2951   case Instruction::Call: {
2952     const CallInst &CI = cast<CallInst>(I);
2953     FunctionType *FTy = CI.getFunctionType();
2954 
2955     if (CI.hasOperandBundles())
2956       writeOperandBundles(&CI, InstID);
2957 
2958     Code = bitc::FUNC_CODE_INST_CALL;
2959 
2960     Vals.push_back(VE.getAttributeListID(CI.getAttributes()));
2961 
2962     unsigned Flags = getOptimizationFlags(&I);
2963     Vals.push_back(CI.getCallingConv() << bitc::CALL_CCONV |
2964                    unsigned(CI.isTailCall()) << bitc::CALL_TAIL |
2965                    unsigned(CI.isMustTailCall()) << bitc::CALL_MUSTTAIL |
2966                    1 << bitc::CALL_EXPLICIT_TYPE |
2967                    unsigned(CI.isNoTailCall()) << bitc::CALL_NOTAIL |
2968                    unsigned(Flags != 0) << bitc::CALL_FMF);
2969     if (Flags != 0)
2970       Vals.push_back(Flags);
2971 
2972     Vals.push_back(VE.getTypeID(FTy));
2973     pushValueAndType(CI.getCalledValue(), InstID, Vals); // Callee
2974 
2975     // Emit value #'s for the fixed parameters.
2976     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
2977       // Check for labels (can happen with asm labels).
2978       if (FTy->getParamType(i)->isLabelTy())
2979         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
2980       else
2981         pushValue(CI.getArgOperand(i), InstID, Vals); // fixed param.
2982     }
2983 
2984     // Emit type/value pairs for varargs params.
2985     if (FTy->isVarArg()) {
2986       for (unsigned i = FTy->getNumParams(), e = CI.getNumArgOperands();
2987            i != e; ++i)
2988         pushValueAndType(CI.getArgOperand(i), InstID, Vals); // varargs
2989     }
2990     break;
2991   }
2992   case Instruction::VAArg:
2993     Code = bitc::FUNC_CODE_INST_VAARG;
2994     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
2995     pushValue(I.getOperand(0), InstID, Vals);                   // valist.
2996     Vals.push_back(VE.getTypeID(I.getType())); // restype.
2997     break;
2998   }
2999 
3000   Stream.EmitRecord(Code, Vals, AbbrevToUse);
3001   Vals.clear();
3002 }
3003 
3004 /// Write a GlobalValue VST to the module. The purpose of this data structure is
3005 /// to allow clients to efficiently find the function body.
3006 void ModuleBitcodeWriter::writeGlobalValueSymbolTable(
3007   DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3008   // Get the offset of the VST we are writing, and backpatch it into
3009   // the VST forward declaration record.
3010   uint64_t VSTOffset = Stream.GetCurrentBitNo();
3011   // The BitcodeStartBit was the stream offset of the identification block.
3012   VSTOffset -= bitcodeStartBit();
3013   assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
3014   // Note that we add 1 here because the offset is relative to one word
3015   // before the start of the identification block, which was historically
3016   // always the start of the regular bitcode header.
3017   Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32 + 1);
3018 
3019   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3020 
3021   auto Abbv = std::make_shared<BitCodeAbbrev>();
3022   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
3023   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
3024   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
3025   unsigned FnEntryAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3026 
3027   for (const Function &F : M) {
3028     uint64_t Record[2];
3029 
3030     if (F.isDeclaration())
3031       continue;
3032 
3033     Record[0] = VE.getValueID(&F);
3034 
3035     // Save the word offset of the function (from the start of the
3036     // actual bitcode written to the stream).
3037     uint64_t BitcodeIndex = FunctionToBitcodeIndex[&F] - bitcodeStartBit();
3038     assert((BitcodeIndex & 31) == 0 && "function block not 32-bit aligned");
3039     // Note that we add 1 here because the offset is relative to one word
3040     // before the start of the identification block, which was historically
3041     // always the start of the regular bitcode header.
3042     Record[1] = BitcodeIndex / 32 + 1;
3043 
3044     Stream.EmitRecord(bitc::VST_CODE_FNENTRY, Record, FnEntryAbbrev);
3045   }
3046 
3047   Stream.ExitBlock();
3048 }
3049 
3050 /// Emit names for arguments, instructions and basic blocks in a function.
3051 void ModuleBitcodeWriter::writeFunctionLevelValueSymbolTable(
3052     const ValueSymbolTable &VST) {
3053   if (VST.empty())
3054     return;
3055 
3056   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3057 
3058   // FIXME: Set up the abbrev, we know how many values there are!
3059   // FIXME: We know if the type names can use 7-bit ascii.
3060   SmallVector<uint64_t, 64> NameVals;
3061 
3062   for (const ValueName &Name : VST) {
3063     // Figure out the encoding to use for the name.
3064     StringEncoding Bits = getStringEncoding(Name.getKey());
3065 
3066     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
3067     NameVals.push_back(VE.getValueID(Name.getValue()));
3068 
3069     // VST_CODE_ENTRY:   [valueid, namechar x N]
3070     // VST_CODE_BBENTRY: [bbid, namechar x N]
3071     unsigned Code;
3072     if (isa<BasicBlock>(Name.getValue())) {
3073       Code = bitc::VST_CODE_BBENTRY;
3074       if (Bits == SE_Char6)
3075         AbbrevToUse = VST_BBENTRY_6_ABBREV;
3076     } else {
3077       Code = bitc::VST_CODE_ENTRY;
3078       if (Bits == SE_Char6)
3079         AbbrevToUse = VST_ENTRY_6_ABBREV;
3080       else if (Bits == SE_Fixed7)
3081         AbbrevToUse = VST_ENTRY_7_ABBREV;
3082     }
3083 
3084     for (const auto P : Name.getKey())
3085       NameVals.push_back((unsigned char)P);
3086 
3087     // Emit the finished record.
3088     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
3089     NameVals.clear();
3090   }
3091 
3092   Stream.ExitBlock();
3093 }
3094 
3095 void ModuleBitcodeWriter::writeUseList(UseListOrder &&Order) {
3096   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
3097   unsigned Code;
3098   if (isa<BasicBlock>(Order.V))
3099     Code = bitc::USELIST_CODE_BB;
3100   else
3101     Code = bitc::USELIST_CODE_DEFAULT;
3102 
3103   SmallVector<uint64_t, 64> Record(Order.Shuffle.begin(), Order.Shuffle.end());
3104   Record.push_back(VE.getValueID(Order.V));
3105   Stream.EmitRecord(Code, Record);
3106 }
3107 
3108 void ModuleBitcodeWriter::writeUseListBlock(const Function *F) {
3109   assert(VE.shouldPreserveUseListOrder() &&
3110          "Expected to be preserving use-list order");
3111 
3112   auto hasMore = [&]() {
3113     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
3114   };
3115   if (!hasMore())
3116     // Nothing to do.
3117     return;
3118 
3119   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
3120   while (hasMore()) {
3121     writeUseList(std::move(VE.UseListOrders.back()));
3122     VE.UseListOrders.pop_back();
3123   }
3124   Stream.ExitBlock();
3125 }
3126 
3127 /// Emit a function body to the module stream.
3128 void ModuleBitcodeWriter::writeFunction(
3129     const Function &F,
3130     DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3131   // Save the bitcode index of the start of this function block for recording
3132   // in the VST.
3133   FunctionToBitcodeIndex[&F] = Stream.GetCurrentBitNo();
3134 
3135   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
3136   VE.incorporateFunction(F);
3137 
3138   SmallVector<unsigned, 64> Vals;
3139 
3140   // Emit the number of basic blocks, so the reader can create them ahead of
3141   // time.
3142   Vals.push_back(VE.getBasicBlocks().size());
3143   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
3144   Vals.clear();
3145 
3146   // If there are function-local constants, emit them now.
3147   unsigned CstStart, CstEnd;
3148   VE.getFunctionConstantRange(CstStart, CstEnd);
3149   writeConstants(CstStart, CstEnd, false);
3150 
3151   // If there is function-local metadata, emit it now.
3152   writeFunctionMetadata(F);
3153 
3154   // Keep a running idea of what the instruction ID is.
3155   unsigned InstID = CstEnd;
3156 
3157   bool NeedsMetadataAttachment = F.hasMetadata();
3158 
3159   DILocation *LastDL = nullptr;
3160   // Finally, emit all the instructions, in order.
3161   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
3162     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
3163          I != E; ++I) {
3164       writeInstruction(*I, InstID, Vals);
3165 
3166       if (!I->getType()->isVoidTy())
3167         ++InstID;
3168 
3169       // If the instruction has metadata, write a metadata attachment later.
3170       NeedsMetadataAttachment |= I->hasMetadataOtherThanDebugLoc();
3171 
3172       // If the instruction has a debug location, emit it.
3173       DILocation *DL = I->getDebugLoc();
3174       if (!DL)
3175         continue;
3176 
3177       if (DL == LastDL) {
3178         // Just repeat the same debug loc as last time.
3179         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
3180         continue;
3181       }
3182 
3183       Vals.push_back(DL->getLine());
3184       Vals.push_back(DL->getColumn());
3185       Vals.push_back(VE.getMetadataOrNullID(DL->getScope()));
3186       Vals.push_back(VE.getMetadataOrNullID(DL->getInlinedAt()));
3187       Vals.push_back(DL->isImplicitCode());
3188       Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
3189       Vals.clear();
3190 
3191       LastDL = DL;
3192     }
3193 
3194   // Emit names for all the instructions etc.
3195   if (auto *Symtab = F.getValueSymbolTable())
3196     writeFunctionLevelValueSymbolTable(*Symtab);
3197 
3198   if (NeedsMetadataAttachment)
3199     writeFunctionMetadataAttachment(F);
3200   if (VE.shouldPreserveUseListOrder())
3201     writeUseListBlock(&F);
3202   VE.purgeFunction();
3203   Stream.ExitBlock();
3204 }
3205 
3206 // Emit blockinfo, which defines the standard abbreviations etc.
3207 void ModuleBitcodeWriter::writeBlockInfo() {
3208   // We only want to emit block info records for blocks that have multiple
3209   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
3210   // Other blocks can define their abbrevs inline.
3211   Stream.EnterBlockInfoBlock();
3212 
3213   { // 8-bit fixed-width VST_CODE_ENTRY/VST_CODE_BBENTRY strings.
3214     auto Abbv = std::make_shared<BitCodeAbbrev>();
3215     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
3216     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3217     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3218     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3219     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3220         VST_ENTRY_8_ABBREV)
3221       llvm_unreachable("Unexpected abbrev ordering!");
3222   }
3223 
3224   { // 7-bit fixed width VST_CODE_ENTRY strings.
3225     auto Abbv = std::make_shared<BitCodeAbbrev>();
3226     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3227     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3228     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3229     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3230     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3231         VST_ENTRY_7_ABBREV)
3232       llvm_unreachable("Unexpected abbrev ordering!");
3233   }
3234   { // 6-bit char6 VST_CODE_ENTRY strings.
3235     auto Abbv = std::make_shared<BitCodeAbbrev>();
3236     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3237     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3238     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3239     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3240     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3241         VST_ENTRY_6_ABBREV)
3242       llvm_unreachable("Unexpected abbrev ordering!");
3243   }
3244   { // 6-bit char6 VST_CODE_BBENTRY strings.
3245     auto Abbv = std::make_shared<BitCodeAbbrev>();
3246     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
3247     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3248     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3249     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3250     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3251         VST_BBENTRY_6_ABBREV)
3252       llvm_unreachable("Unexpected abbrev ordering!");
3253   }
3254 
3255   { // SETTYPE abbrev for CONSTANTS_BLOCK.
3256     auto Abbv = std::make_shared<BitCodeAbbrev>();
3257     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
3258     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
3259                               VE.computeBitsRequiredForTypeIndicies()));
3260     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3261         CONSTANTS_SETTYPE_ABBREV)
3262       llvm_unreachable("Unexpected abbrev ordering!");
3263   }
3264 
3265   { // INTEGER abbrev for CONSTANTS_BLOCK.
3266     auto Abbv = std::make_shared<BitCodeAbbrev>();
3267     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
3268     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3269     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3270         CONSTANTS_INTEGER_ABBREV)
3271       llvm_unreachable("Unexpected abbrev ordering!");
3272   }
3273 
3274   { // CE_CAST abbrev for CONSTANTS_BLOCK.
3275     auto Abbv = std::make_shared<BitCodeAbbrev>();
3276     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
3277     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
3278     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
3279                               VE.computeBitsRequiredForTypeIndicies()));
3280     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
3281 
3282     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3283         CONSTANTS_CE_CAST_Abbrev)
3284       llvm_unreachable("Unexpected abbrev ordering!");
3285   }
3286   { // NULL abbrev for CONSTANTS_BLOCK.
3287     auto Abbv = std::make_shared<BitCodeAbbrev>();
3288     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
3289     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3290         CONSTANTS_NULL_Abbrev)
3291       llvm_unreachable("Unexpected abbrev ordering!");
3292   }
3293 
3294   // FIXME: This should only use space for first class types!
3295 
3296   { // INST_LOAD abbrev for FUNCTION_BLOCK.
3297     auto Abbv = std::make_shared<BitCodeAbbrev>();
3298     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
3299     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
3300     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
3301                               VE.computeBitsRequiredForTypeIndicies()));
3302     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
3303     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
3304     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3305         FUNCTION_INST_LOAD_ABBREV)
3306       llvm_unreachable("Unexpected abbrev ordering!");
3307   }
3308   { // INST_UNOP abbrev for FUNCTION_BLOCK.
3309     auto Abbv = std::make_shared<BitCodeAbbrev>();
3310     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3311     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3312     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3313     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3314         FUNCTION_INST_UNOP_ABBREV)
3315       llvm_unreachable("Unexpected abbrev ordering!");
3316   }
3317   { // INST_UNOP_FLAGS abbrev for FUNCTION_BLOCK.
3318     auto Abbv = std::make_shared<BitCodeAbbrev>();
3319     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3320     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3321     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3322     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3323     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3324         FUNCTION_INST_UNOP_FLAGS_ABBREV)
3325       llvm_unreachable("Unexpected abbrev ordering!");
3326   }
3327   { // INST_BINOP abbrev for FUNCTION_BLOCK.
3328     auto Abbv = std::make_shared<BitCodeAbbrev>();
3329     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3330     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3331     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3332     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3333     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3334         FUNCTION_INST_BINOP_ABBREV)
3335       llvm_unreachable("Unexpected abbrev ordering!");
3336   }
3337   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
3338     auto Abbv = std::make_shared<BitCodeAbbrev>();
3339     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3340     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3341     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3342     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3343     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3344     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3345         FUNCTION_INST_BINOP_FLAGS_ABBREV)
3346       llvm_unreachable("Unexpected abbrev ordering!");
3347   }
3348   { // INST_CAST abbrev for FUNCTION_BLOCK.
3349     auto Abbv = std::make_shared<BitCodeAbbrev>();
3350     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
3351     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
3352     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
3353                               VE.computeBitsRequiredForTypeIndicies()));
3354     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
3355     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3356         FUNCTION_INST_CAST_ABBREV)
3357       llvm_unreachable("Unexpected abbrev ordering!");
3358   }
3359 
3360   { // INST_RET abbrev for FUNCTION_BLOCK.
3361     auto Abbv = std::make_shared<BitCodeAbbrev>();
3362     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3363     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3364         FUNCTION_INST_RET_VOID_ABBREV)
3365       llvm_unreachable("Unexpected abbrev ordering!");
3366   }
3367   { // INST_RET abbrev for FUNCTION_BLOCK.
3368     auto Abbv = std::make_shared<BitCodeAbbrev>();
3369     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3370     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
3371     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3372         FUNCTION_INST_RET_VAL_ABBREV)
3373       llvm_unreachable("Unexpected abbrev ordering!");
3374   }
3375   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
3376     auto Abbv = std::make_shared<BitCodeAbbrev>();
3377     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
3378     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3379         FUNCTION_INST_UNREACHABLE_ABBREV)
3380       llvm_unreachable("Unexpected abbrev ordering!");
3381   }
3382   {
3383     auto Abbv = std::make_shared<BitCodeAbbrev>();
3384     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_GEP));
3385     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
3386     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, // dest ty
3387                               Log2_32_Ceil(VE.getTypes().size() + 1)));
3388     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3389     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
3390     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3391         FUNCTION_INST_GEP_ABBREV)
3392       llvm_unreachable("Unexpected abbrev ordering!");
3393   }
3394 
3395   Stream.ExitBlock();
3396 }
3397 
3398 /// Write the module path strings, currently only used when generating
3399 /// a combined index file.
3400 void IndexBitcodeWriter::writeModStrings() {
3401   Stream.EnterSubblock(bitc::MODULE_STRTAB_BLOCK_ID, 3);
3402 
3403   // TODO: See which abbrev sizes we actually need to emit
3404 
3405   // 8-bit fixed-width MST_ENTRY strings.
3406   auto Abbv = std::make_shared<BitCodeAbbrev>();
3407   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3408   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3409   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3410   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3411   unsigned Abbrev8Bit = Stream.EmitAbbrev(std::move(Abbv));
3412 
3413   // 7-bit fixed width MST_ENTRY strings.
3414   Abbv = std::make_shared<BitCodeAbbrev>();
3415   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3416   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3417   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3418   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3419   unsigned Abbrev7Bit = Stream.EmitAbbrev(std::move(Abbv));
3420 
3421   // 6-bit char6 MST_ENTRY strings.
3422   Abbv = std::make_shared<BitCodeAbbrev>();
3423   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3424   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3425   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3426   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3427   unsigned Abbrev6Bit = Stream.EmitAbbrev(std::move(Abbv));
3428 
3429   // Module Hash, 160 bits SHA1. Optionally, emitted after each MST_CODE_ENTRY.
3430   Abbv = std::make_shared<BitCodeAbbrev>();
3431   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_HASH));
3432   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3433   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3434   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3435   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3436   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3437   unsigned AbbrevHash = Stream.EmitAbbrev(std::move(Abbv));
3438 
3439   SmallVector<unsigned, 64> Vals;
3440   forEachModule(
3441       [&](const StringMapEntry<std::pair<uint64_t, ModuleHash>> &MPSE) {
3442         StringRef Key = MPSE.getKey();
3443         const auto &Value = MPSE.getValue();
3444         StringEncoding Bits = getStringEncoding(Key);
3445         unsigned AbbrevToUse = Abbrev8Bit;
3446         if (Bits == SE_Char6)
3447           AbbrevToUse = Abbrev6Bit;
3448         else if (Bits == SE_Fixed7)
3449           AbbrevToUse = Abbrev7Bit;
3450 
3451         Vals.push_back(Value.first);
3452         Vals.append(Key.begin(), Key.end());
3453 
3454         // Emit the finished record.
3455         Stream.EmitRecord(bitc::MST_CODE_ENTRY, Vals, AbbrevToUse);
3456 
3457         // Emit an optional hash for the module now
3458         const auto &Hash = Value.second;
3459         if (llvm::any_of(Hash, [](uint32_t H) { return H; })) {
3460           Vals.assign(Hash.begin(), Hash.end());
3461           // Emit the hash record.
3462           Stream.EmitRecord(bitc::MST_CODE_HASH, Vals, AbbrevHash);
3463         }
3464 
3465         Vals.clear();
3466       });
3467   Stream.ExitBlock();
3468 }
3469 
3470 /// Write the function type metadata related records that need to appear before
3471 /// a function summary entry (whether per-module or combined).
3472 static void writeFunctionTypeMetadataRecords(BitstreamWriter &Stream,
3473                                              FunctionSummary *FS) {
3474   if (!FS->type_tests().empty())
3475     Stream.EmitRecord(bitc::FS_TYPE_TESTS, FS->type_tests());
3476 
3477   SmallVector<uint64_t, 64> Record;
3478 
3479   auto WriteVFuncIdVec = [&](uint64_t Ty,
3480                              ArrayRef<FunctionSummary::VFuncId> VFs) {
3481     if (VFs.empty())
3482       return;
3483     Record.clear();
3484     for (auto &VF : VFs) {
3485       Record.push_back(VF.GUID);
3486       Record.push_back(VF.Offset);
3487     }
3488     Stream.EmitRecord(Ty, Record);
3489   };
3490 
3491   WriteVFuncIdVec(bitc::FS_TYPE_TEST_ASSUME_VCALLS,
3492                   FS->type_test_assume_vcalls());
3493   WriteVFuncIdVec(bitc::FS_TYPE_CHECKED_LOAD_VCALLS,
3494                   FS->type_checked_load_vcalls());
3495 
3496   auto WriteConstVCallVec = [&](uint64_t Ty,
3497                                 ArrayRef<FunctionSummary::ConstVCall> VCs) {
3498     for (auto &VC : VCs) {
3499       Record.clear();
3500       Record.push_back(VC.VFunc.GUID);
3501       Record.push_back(VC.VFunc.Offset);
3502       Record.insert(Record.end(), VC.Args.begin(), VC.Args.end());
3503       Stream.EmitRecord(Ty, Record);
3504     }
3505   };
3506 
3507   WriteConstVCallVec(bitc::FS_TYPE_TEST_ASSUME_CONST_VCALL,
3508                      FS->type_test_assume_const_vcalls());
3509   WriteConstVCallVec(bitc::FS_TYPE_CHECKED_LOAD_CONST_VCALL,
3510                      FS->type_checked_load_const_vcalls());
3511 }
3512 
3513 /// Collect type IDs from type tests used by function.
3514 static void
3515 getReferencedTypeIds(FunctionSummary *FS,
3516                      std::set<GlobalValue::GUID> &ReferencedTypeIds) {
3517   if (!FS->type_tests().empty())
3518     for (auto &TT : FS->type_tests())
3519       ReferencedTypeIds.insert(TT);
3520 
3521   auto GetReferencedTypesFromVFuncIdVec =
3522       [&](ArrayRef<FunctionSummary::VFuncId> VFs) {
3523         for (auto &VF : VFs)
3524           ReferencedTypeIds.insert(VF.GUID);
3525       };
3526 
3527   GetReferencedTypesFromVFuncIdVec(FS->type_test_assume_vcalls());
3528   GetReferencedTypesFromVFuncIdVec(FS->type_checked_load_vcalls());
3529 
3530   auto GetReferencedTypesFromConstVCallVec =
3531       [&](ArrayRef<FunctionSummary::ConstVCall> VCs) {
3532         for (auto &VC : VCs)
3533           ReferencedTypeIds.insert(VC.VFunc.GUID);
3534       };
3535 
3536   GetReferencedTypesFromConstVCallVec(FS->type_test_assume_const_vcalls());
3537   GetReferencedTypesFromConstVCallVec(FS->type_checked_load_const_vcalls());
3538 }
3539 
3540 static void writeWholeProgramDevirtResolutionByArg(
3541     SmallVector<uint64_t, 64> &NameVals, const std::vector<uint64_t> &args,
3542     const WholeProgramDevirtResolution::ByArg &ByArg) {
3543   NameVals.push_back(args.size());
3544   NameVals.insert(NameVals.end(), args.begin(), args.end());
3545 
3546   NameVals.push_back(ByArg.TheKind);
3547   NameVals.push_back(ByArg.Info);
3548   NameVals.push_back(ByArg.Byte);
3549   NameVals.push_back(ByArg.Bit);
3550 }
3551 
3552 static void writeWholeProgramDevirtResolution(
3553     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3554     uint64_t Id, const WholeProgramDevirtResolution &Wpd) {
3555   NameVals.push_back(Id);
3556 
3557   NameVals.push_back(Wpd.TheKind);
3558   NameVals.push_back(StrtabBuilder.add(Wpd.SingleImplName));
3559   NameVals.push_back(Wpd.SingleImplName.size());
3560 
3561   NameVals.push_back(Wpd.ResByArg.size());
3562   for (auto &A : Wpd.ResByArg)
3563     writeWholeProgramDevirtResolutionByArg(NameVals, A.first, A.second);
3564 }
3565 
3566 static void writeTypeIdSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
3567                                      StringTableBuilder &StrtabBuilder,
3568                                      const std::string &Id,
3569                                      const TypeIdSummary &Summary) {
3570   NameVals.push_back(StrtabBuilder.add(Id));
3571   NameVals.push_back(Id.size());
3572 
3573   NameVals.push_back(Summary.TTRes.TheKind);
3574   NameVals.push_back(Summary.TTRes.SizeM1BitWidth);
3575   NameVals.push_back(Summary.TTRes.AlignLog2);
3576   NameVals.push_back(Summary.TTRes.SizeM1);
3577   NameVals.push_back(Summary.TTRes.BitMask);
3578   NameVals.push_back(Summary.TTRes.InlineBits);
3579 
3580   for (auto &W : Summary.WPDRes)
3581     writeWholeProgramDevirtResolution(NameVals, StrtabBuilder, W.first,
3582                                       W.second);
3583 }
3584 
3585 // Helper to emit a single function summary record.
3586 void ModuleBitcodeWriterBase::writePerModuleFunctionSummaryRecord(
3587     SmallVector<uint64_t, 64> &NameVals, GlobalValueSummary *Summary,
3588     unsigned ValueID, unsigned FSCallsAbbrev, unsigned FSCallsProfileAbbrev,
3589     const Function &F) {
3590   NameVals.push_back(ValueID);
3591 
3592   FunctionSummary *FS = cast<FunctionSummary>(Summary);
3593   writeFunctionTypeMetadataRecords(Stream, FS);
3594 
3595   NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
3596   NameVals.push_back(FS->instCount());
3597   NameVals.push_back(getEncodedFFlags(FS->fflags()));
3598   NameVals.push_back(FS->refs().size());
3599   NameVals.push_back(FS->immutableRefCount());
3600 
3601   for (auto &RI : FS->refs())
3602     NameVals.push_back(VE.getValueID(RI.getValue()));
3603 
3604   bool HasProfileData =
3605       F.hasProfileData() || ForceSummaryEdgesCold != FunctionSummary::FSHT_None;
3606   for (auto &ECI : FS->calls()) {
3607     NameVals.push_back(getValueId(ECI.first));
3608     if (HasProfileData)
3609       NameVals.push_back(static_cast<uint8_t>(ECI.second.Hotness));
3610     else if (WriteRelBFToSummary)
3611       NameVals.push_back(ECI.second.RelBlockFreq);
3612   }
3613 
3614   unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
3615   unsigned Code =
3616       (HasProfileData ? bitc::FS_PERMODULE_PROFILE
3617                       : (WriteRelBFToSummary ? bitc::FS_PERMODULE_RELBF
3618                                              : bitc::FS_PERMODULE));
3619 
3620   // Emit the finished record.
3621   Stream.EmitRecord(Code, NameVals, FSAbbrev);
3622   NameVals.clear();
3623 }
3624 
3625 // Collect the global value references in the given variable's initializer,
3626 // and emit them in a summary record.
3627 void ModuleBitcodeWriterBase::writeModuleLevelReferences(
3628     const GlobalVariable &V, SmallVector<uint64_t, 64> &NameVals,
3629     unsigned FSModRefsAbbrev) {
3630   auto VI = Index->getValueInfo(V.getGUID());
3631   if (!VI || VI.getSummaryList().empty()) {
3632     // Only declarations should not have a summary (a declaration might however
3633     // have a summary if the def was in module level asm).
3634     assert(V.isDeclaration());
3635     return;
3636   }
3637   auto *Summary = VI.getSummaryList()[0].get();
3638   NameVals.push_back(VE.getValueID(&V));
3639   GlobalVarSummary *VS = cast<GlobalVarSummary>(Summary);
3640   NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
3641   NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
3642 
3643   unsigned SizeBeforeRefs = NameVals.size();
3644   for (auto &RI : VS->refs())
3645     NameVals.push_back(VE.getValueID(RI.getValue()));
3646   // Sort the refs for determinism output, the vector returned by FS->refs() has
3647   // been initialized from a DenseSet.
3648   llvm::sort(NameVals.begin() + SizeBeforeRefs, NameVals.end());
3649 
3650   Stream.EmitRecord(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS, NameVals,
3651                     FSModRefsAbbrev);
3652   NameVals.clear();
3653 }
3654 
3655 // Current version for the summary.
3656 // This is bumped whenever we introduce changes in the way some record are
3657 // interpreted, like flags for instance.
3658 static const uint64_t INDEX_VERSION = 6;
3659 
3660 /// Emit the per-module summary section alongside the rest of
3661 /// the module's bitcode.
3662 void ModuleBitcodeWriterBase::writePerModuleGlobalValueSummary() {
3663   // By default we compile with ThinLTO if the module has a summary, but the
3664   // client can request full LTO with a module flag.
3665   bool IsThinLTO = true;
3666   if (auto *MD =
3667           mdconst::extract_or_null<ConstantInt>(M.getModuleFlag("ThinLTO")))
3668     IsThinLTO = MD->getZExtValue();
3669   Stream.EnterSubblock(IsThinLTO ? bitc::GLOBALVAL_SUMMARY_BLOCK_ID
3670                                  : bitc::FULL_LTO_GLOBALVAL_SUMMARY_BLOCK_ID,
3671                        4);
3672 
3673   Stream.EmitRecord(bitc::FS_VERSION, ArrayRef<uint64_t>{INDEX_VERSION});
3674 
3675   // Write the index flags.
3676   uint64_t Flags = 0;
3677   // Bits 1-3 are set only in the combined index, skip them.
3678   if (Index->enableSplitLTOUnit())
3679     Flags |= 0x8;
3680   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Flags});
3681 
3682   if (Index->begin() == Index->end()) {
3683     Stream.ExitBlock();
3684     return;
3685   }
3686 
3687   for (const auto &GVI : valueIds()) {
3688     Stream.EmitRecord(bitc::FS_VALUE_GUID,
3689                       ArrayRef<uint64_t>{GVI.second, GVI.first});
3690   }
3691 
3692   // Abbrev for FS_PERMODULE_PROFILE.
3693   auto Abbv = std::make_shared<BitCodeAbbrev>();
3694   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_PROFILE));
3695   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3696   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3697   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3698   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3699   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3700   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // immutablerefcnt
3701   // numrefs x valueid, n x (valueid, hotness)
3702   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3703   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3704   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3705 
3706   // Abbrev for FS_PERMODULE or FS_PERMODULE_RELBF.
3707   Abbv = std::make_shared<BitCodeAbbrev>();
3708   if (WriteRelBFToSummary)
3709     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_RELBF));
3710   else
3711     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE));
3712   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3713   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3714   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3715   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3716   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3717   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // immutablerefcnt
3718   // numrefs x valueid, n x (valueid [, rel_block_freq])
3719   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3720   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3721   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3722 
3723   // Abbrev for FS_PERMODULE_GLOBALVAR_INIT_REFS.
3724   Abbv = std::make_shared<BitCodeAbbrev>();
3725   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS));
3726   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
3727   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
3728   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));  // valueids
3729   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3730   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3731 
3732   // Abbrev for FS_ALIAS.
3733   Abbv = std::make_shared<BitCodeAbbrev>();
3734   Abbv->Add(BitCodeAbbrevOp(bitc::FS_ALIAS));
3735   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3736   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3737   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3738   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3739 
3740   SmallVector<uint64_t, 64> NameVals;
3741   // Iterate over the list of functions instead of the Index to
3742   // ensure the ordering is stable.
3743   for (const Function &F : M) {
3744     // Summary emission does not support anonymous functions, they have to
3745     // renamed using the anonymous function renaming pass.
3746     if (!F.hasName())
3747       report_fatal_error("Unexpected anonymous function when writing summary");
3748 
3749     ValueInfo VI = Index->getValueInfo(F.getGUID());
3750     if (!VI || VI.getSummaryList().empty()) {
3751       // Only declarations should not have a summary (a declaration might
3752       // however have a summary if the def was in module level asm).
3753       assert(F.isDeclaration());
3754       continue;
3755     }
3756     auto *Summary = VI.getSummaryList()[0].get();
3757     writePerModuleFunctionSummaryRecord(NameVals, Summary, VE.getValueID(&F),
3758                                         FSCallsAbbrev, FSCallsProfileAbbrev, F);
3759   }
3760 
3761   // Capture references from GlobalVariable initializers, which are outside
3762   // of a function scope.
3763   for (const GlobalVariable &G : M.globals())
3764     writeModuleLevelReferences(G, NameVals, FSModRefsAbbrev);
3765 
3766   for (const GlobalAlias &A : M.aliases()) {
3767     auto *Aliasee = A.getBaseObject();
3768     if (!Aliasee->hasName())
3769       // Nameless function don't have an entry in the summary, skip it.
3770       continue;
3771     auto AliasId = VE.getValueID(&A);
3772     auto AliaseeId = VE.getValueID(Aliasee);
3773     NameVals.push_back(AliasId);
3774     auto *Summary = Index->getGlobalValueSummary(A);
3775     AliasSummary *AS = cast<AliasSummary>(Summary);
3776     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
3777     NameVals.push_back(AliaseeId);
3778     Stream.EmitRecord(bitc::FS_ALIAS, NameVals, FSAliasAbbrev);
3779     NameVals.clear();
3780   }
3781 
3782   Stream.ExitBlock();
3783 }
3784 
3785 /// Emit the combined summary section into the combined index file.
3786 void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
3787   Stream.EnterSubblock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID, 3);
3788   Stream.EmitRecord(bitc::FS_VERSION, ArrayRef<uint64_t>{INDEX_VERSION});
3789 
3790   // Write the index flags.
3791   uint64_t Flags = 0;
3792   if (Index.withGlobalValueDeadStripping())
3793     Flags |= 0x1;
3794   if (Index.skipModuleByDistributedBackend())
3795     Flags |= 0x2;
3796   if (Index.hasSyntheticEntryCounts())
3797     Flags |= 0x4;
3798   if (Index.enableSplitLTOUnit())
3799     Flags |= 0x8;
3800   if (Index.partiallySplitLTOUnits())
3801     Flags |= 0x10;
3802   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Flags});
3803 
3804   for (const auto &GVI : valueIds()) {
3805     Stream.EmitRecord(bitc::FS_VALUE_GUID,
3806                       ArrayRef<uint64_t>{GVI.second, GVI.first});
3807   }
3808 
3809   // Abbrev for FS_COMBINED.
3810   auto Abbv = std::make_shared<BitCodeAbbrev>();
3811   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED));
3812   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3813   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3814   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3815   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3816   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3817   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
3818   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3819   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // immutablerefcnt
3820   // numrefs x valueid, n x (valueid)
3821   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3822   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3823   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3824 
3825   // Abbrev for FS_COMBINED_PROFILE.
3826   Abbv = std::make_shared<BitCodeAbbrev>();
3827   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_PROFILE));
3828   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3829   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3830   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3831   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3832   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3833   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3834   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // immutablerefcnt
3835   // numrefs x valueid, n x (valueid, hotness)
3836   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3837   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3838   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3839 
3840   // Abbrev for FS_COMBINED_GLOBALVAR_INIT_REFS.
3841   Abbv = std::make_shared<BitCodeAbbrev>();
3842   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS));
3843   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3844   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3845   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3846   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));    // valueids
3847   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3848   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3849 
3850   // Abbrev for FS_COMBINED_ALIAS.
3851   Abbv = std::make_shared<BitCodeAbbrev>();
3852   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_ALIAS));
3853   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3854   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3855   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3856   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3857   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3858 
3859   // The aliases are emitted as a post-pass, and will point to the value
3860   // id of the aliasee. Save them in a vector for post-processing.
3861   SmallVector<AliasSummary *, 64> Aliases;
3862 
3863   // Save the value id for each summary for alias emission.
3864   DenseMap<const GlobalValueSummary *, unsigned> SummaryToValueIdMap;
3865 
3866   SmallVector<uint64_t, 64> NameVals;
3867 
3868   // Set that will be populated during call to writeFunctionTypeMetadataRecords
3869   // with the type ids referenced by this index file.
3870   std::set<GlobalValue::GUID> ReferencedTypeIds;
3871 
3872   // For local linkage, we also emit the original name separately
3873   // immediately after the record.
3874   auto MaybeEmitOriginalName = [&](GlobalValueSummary &S) {
3875     if (!GlobalValue::isLocalLinkage(S.linkage()))
3876       return;
3877     NameVals.push_back(S.getOriginalName());
3878     Stream.EmitRecord(bitc::FS_COMBINED_ORIGINAL_NAME, NameVals);
3879     NameVals.clear();
3880   };
3881 
3882   forEachSummary([&](GVInfo I, bool IsAliasee) {
3883     GlobalValueSummary *S = I.second;
3884     assert(S);
3885 
3886     auto ValueId = getValueId(I.first);
3887     assert(ValueId);
3888     SummaryToValueIdMap[S] = *ValueId;
3889 
3890     // If this is invoked for an aliasee, we want to record the above
3891     // mapping, but then not emit a summary entry (if the aliasee is
3892     // to be imported, we will invoke this separately with IsAliasee=false).
3893     if (IsAliasee)
3894       return;
3895 
3896     if (auto *AS = dyn_cast<AliasSummary>(S)) {
3897       // Will process aliases as a post-pass because the reader wants all
3898       // global to be loaded first.
3899       Aliases.push_back(AS);
3900       return;
3901     }
3902 
3903     if (auto *VS = dyn_cast<GlobalVarSummary>(S)) {
3904       NameVals.push_back(*ValueId);
3905       NameVals.push_back(Index.getModuleId(VS->modulePath()));
3906       NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
3907       NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
3908       for (auto &RI : VS->refs()) {
3909         auto RefValueId = getValueId(RI.getGUID());
3910         if (!RefValueId)
3911           continue;
3912         NameVals.push_back(*RefValueId);
3913       }
3914 
3915       // Emit the finished record.
3916       Stream.EmitRecord(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS, NameVals,
3917                         FSModRefsAbbrev);
3918       NameVals.clear();
3919       MaybeEmitOriginalName(*S);
3920       return;
3921     }
3922 
3923     auto *FS = cast<FunctionSummary>(S);
3924     writeFunctionTypeMetadataRecords(Stream, FS);
3925     getReferencedTypeIds(FS, ReferencedTypeIds);
3926 
3927     NameVals.push_back(*ValueId);
3928     NameVals.push_back(Index.getModuleId(FS->modulePath()));
3929     NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
3930     NameVals.push_back(FS->instCount());
3931     NameVals.push_back(getEncodedFFlags(FS->fflags()));
3932     NameVals.push_back(FS->entryCount());
3933 
3934     // Fill in below
3935     NameVals.push_back(0); // numrefs
3936     NameVals.push_back(0); // immutablerefcnt
3937 
3938     unsigned Count = 0, ImmutableRefCnt = 0;
3939     for (auto &RI : FS->refs()) {
3940       auto RefValueId = getValueId(RI.getGUID());
3941       if (!RefValueId)
3942         continue;
3943       NameVals.push_back(*RefValueId);
3944       if (RI.isReadOnly())
3945         ImmutableRefCnt++;
3946       Count++;
3947     }
3948     NameVals[6] = Count;
3949     NameVals[7] = ImmutableRefCnt;
3950 
3951     bool HasProfileData = false;
3952     for (auto &EI : FS->calls()) {
3953       HasProfileData |=
3954           EI.second.getHotness() != CalleeInfo::HotnessType::Unknown;
3955       if (HasProfileData)
3956         break;
3957     }
3958 
3959     for (auto &EI : FS->calls()) {
3960       // If this GUID doesn't have a value id, it doesn't have a function
3961       // summary and we don't need to record any calls to it.
3962       GlobalValue::GUID GUID = EI.first.getGUID();
3963       auto CallValueId = getValueId(GUID);
3964       if (!CallValueId) {
3965         // For SamplePGO, the indirect call targets for local functions will
3966         // have its original name annotated in profile. We try to find the
3967         // corresponding PGOFuncName as the GUID.
3968         GUID = Index.getGUIDFromOriginalID(GUID);
3969         if (GUID == 0)
3970           continue;
3971         CallValueId = getValueId(GUID);
3972         if (!CallValueId)
3973           continue;
3974         // The mapping from OriginalId to GUID may return a GUID
3975         // that corresponds to a static variable. Filter it out here.
3976         // This can happen when
3977         // 1) There is a call to a library function which does not have
3978         // a CallValidId;
3979         // 2) There is a static variable with the  OriginalGUID identical
3980         // to the GUID of the library function in 1);
3981         // When this happens, the logic for SamplePGO kicks in and
3982         // the static variable in 2) will be found, which needs to be
3983         // filtered out.
3984         auto *GVSum = Index.getGlobalValueSummary(GUID, false);
3985         if (GVSum &&
3986             GVSum->getSummaryKind() == GlobalValueSummary::GlobalVarKind)
3987           continue;
3988       }
3989       NameVals.push_back(*CallValueId);
3990       if (HasProfileData)
3991         NameVals.push_back(static_cast<uint8_t>(EI.second.Hotness));
3992     }
3993 
3994     unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
3995     unsigned Code =
3996         (HasProfileData ? bitc::FS_COMBINED_PROFILE : bitc::FS_COMBINED);
3997 
3998     // Emit the finished record.
3999     Stream.EmitRecord(Code, NameVals, FSAbbrev);
4000     NameVals.clear();
4001     MaybeEmitOriginalName(*S);
4002   });
4003 
4004   for (auto *AS : Aliases) {
4005     auto AliasValueId = SummaryToValueIdMap[AS];
4006     assert(AliasValueId);
4007     NameVals.push_back(AliasValueId);
4008     NameVals.push_back(Index.getModuleId(AS->modulePath()));
4009     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
4010     auto AliaseeValueId = SummaryToValueIdMap[&AS->getAliasee()];
4011     assert(AliaseeValueId);
4012     NameVals.push_back(AliaseeValueId);
4013 
4014     // Emit the finished record.
4015     Stream.EmitRecord(bitc::FS_COMBINED_ALIAS, NameVals, FSAliasAbbrev);
4016     NameVals.clear();
4017     MaybeEmitOriginalName(*AS);
4018 
4019     if (auto *FS = dyn_cast<FunctionSummary>(&AS->getAliasee()))
4020       getReferencedTypeIds(FS, ReferencedTypeIds);
4021   }
4022 
4023   if (!Index.cfiFunctionDefs().empty()) {
4024     for (auto &S : Index.cfiFunctionDefs()) {
4025       NameVals.push_back(StrtabBuilder.add(S));
4026       NameVals.push_back(S.size());
4027     }
4028     Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DEFS, NameVals);
4029     NameVals.clear();
4030   }
4031 
4032   if (!Index.cfiFunctionDecls().empty()) {
4033     for (auto &S : Index.cfiFunctionDecls()) {
4034       NameVals.push_back(StrtabBuilder.add(S));
4035       NameVals.push_back(S.size());
4036     }
4037     Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DECLS, NameVals);
4038     NameVals.clear();
4039   }
4040 
4041   // Walk the GUIDs that were referenced, and write the
4042   // corresponding type id records.
4043   for (auto &T : ReferencedTypeIds) {
4044     auto TidIter = Index.typeIds().equal_range(T);
4045     for (auto It = TidIter.first; It != TidIter.second; ++It) {
4046       writeTypeIdSummaryRecord(NameVals, StrtabBuilder, It->second.first,
4047                                It->second.second);
4048       Stream.EmitRecord(bitc::FS_TYPE_ID, NameVals);
4049       NameVals.clear();
4050     }
4051   }
4052 
4053   Stream.ExitBlock();
4054 }
4055 
4056 /// Create the "IDENTIFICATION_BLOCK_ID" containing a single string with the
4057 /// current llvm version, and a record for the epoch number.
4058 static void writeIdentificationBlock(BitstreamWriter &Stream) {
4059   Stream.EnterSubblock(bitc::IDENTIFICATION_BLOCK_ID, 5);
4060 
4061   // Write the "user readable" string identifying the bitcode producer
4062   auto Abbv = std::make_shared<BitCodeAbbrev>();
4063   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_STRING));
4064   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4065   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
4066   auto StringAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4067   writeStringRecord(Stream, bitc::IDENTIFICATION_CODE_STRING,
4068                     "LLVM" LLVM_VERSION_STRING, StringAbbrev);
4069 
4070   // Write the epoch version
4071   Abbv = std::make_shared<BitCodeAbbrev>();
4072   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_EPOCH));
4073   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
4074   auto EpochAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4075   SmallVector<unsigned, 1> Vals = {bitc::BITCODE_CURRENT_EPOCH};
4076   Stream.EmitRecord(bitc::IDENTIFICATION_CODE_EPOCH, Vals, EpochAbbrev);
4077   Stream.ExitBlock();
4078 }
4079 
4080 void ModuleBitcodeWriter::writeModuleHash(size_t BlockStartPos) {
4081   // Emit the module's hash.
4082   // MODULE_CODE_HASH: [5*i32]
4083   if (GenerateHash) {
4084     uint32_t Vals[5];
4085     Hasher.update(ArrayRef<uint8_t>((const uint8_t *)&(Buffer)[BlockStartPos],
4086                                     Buffer.size() - BlockStartPos));
4087     StringRef Hash = Hasher.result();
4088     for (int Pos = 0; Pos < 20; Pos += 4) {
4089       Vals[Pos / 4] = support::endian::read32be(Hash.data() + Pos);
4090     }
4091 
4092     // Emit the finished record.
4093     Stream.EmitRecord(bitc::MODULE_CODE_HASH, Vals);
4094 
4095     if (ModHash)
4096       // Save the written hash value.
4097       llvm::copy(Vals, std::begin(*ModHash));
4098   }
4099 }
4100 
4101 void ModuleBitcodeWriter::write() {
4102   writeIdentificationBlock(Stream);
4103 
4104   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4105   size_t BlockStartPos = Buffer.size();
4106 
4107   writeModuleVersion();
4108 
4109   // Emit blockinfo, which defines the standard abbreviations etc.
4110   writeBlockInfo();
4111 
4112   // Emit information about attribute groups.
4113   writeAttributeGroupTable();
4114 
4115   // Emit information about parameter attributes.
4116   writeAttributeTable();
4117 
4118   // Emit information describing all of the types in the module.
4119   writeTypeTable();
4120 
4121   writeComdats();
4122 
4123   // Emit top-level description of module, including target triple, inline asm,
4124   // descriptors for global variables, and function prototype info.
4125   writeModuleInfo();
4126 
4127   // Emit constants.
4128   writeModuleConstants();
4129 
4130   // Emit metadata kind names.
4131   writeModuleMetadataKinds();
4132 
4133   // Emit metadata.
4134   writeModuleMetadata();
4135 
4136   // Emit module-level use-lists.
4137   if (VE.shouldPreserveUseListOrder())
4138     writeUseListBlock(nullptr);
4139 
4140   writeOperandBundleTags();
4141   writeSyncScopeNames();
4142 
4143   // Emit function bodies.
4144   DenseMap<const Function *, uint64_t> FunctionToBitcodeIndex;
4145   for (Module::const_iterator F = M.begin(), E = M.end(); F != E; ++F)
4146     if (!F->isDeclaration())
4147       writeFunction(*F, FunctionToBitcodeIndex);
4148 
4149   // Need to write after the above call to WriteFunction which populates
4150   // the summary information in the index.
4151   if (Index)
4152     writePerModuleGlobalValueSummary();
4153 
4154   writeGlobalValueSymbolTable(FunctionToBitcodeIndex);
4155 
4156   writeModuleHash(BlockStartPos);
4157 
4158   Stream.ExitBlock();
4159 }
4160 
4161 static void writeInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
4162                                uint32_t &Position) {
4163   support::endian::write32le(&Buffer[Position], Value);
4164   Position += 4;
4165 }
4166 
4167 /// If generating a bc file on darwin, we have to emit a
4168 /// header and trailer to make it compatible with the system archiver.  To do
4169 /// this we emit the following header, and then emit a trailer that pads the
4170 /// file out to be a multiple of 16 bytes.
4171 ///
4172 /// struct bc_header {
4173 ///   uint32_t Magic;         // 0x0B17C0DE
4174 ///   uint32_t Version;       // Version, currently always 0.
4175 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
4176 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
4177 ///   uint32_t CPUType;       // CPU specifier.
4178 ///   ... potentially more later ...
4179 /// };
4180 static void emitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
4181                                          const Triple &TT) {
4182   unsigned CPUType = ~0U;
4183 
4184   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
4185   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
4186   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
4187   // specific constants here because they are implicitly part of the Darwin ABI.
4188   enum {
4189     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
4190     DARWIN_CPU_TYPE_X86        = 7,
4191     DARWIN_CPU_TYPE_ARM        = 12,
4192     DARWIN_CPU_TYPE_POWERPC    = 18
4193   };
4194 
4195   Triple::ArchType Arch = TT.getArch();
4196   if (Arch == Triple::x86_64)
4197     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
4198   else if (Arch == Triple::x86)
4199     CPUType = DARWIN_CPU_TYPE_X86;
4200   else if (Arch == Triple::ppc)
4201     CPUType = DARWIN_CPU_TYPE_POWERPC;
4202   else if (Arch == Triple::ppc64)
4203     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
4204   else if (Arch == Triple::arm || Arch == Triple::thumb)
4205     CPUType = DARWIN_CPU_TYPE_ARM;
4206 
4207   // Traditional Bitcode starts after header.
4208   assert(Buffer.size() >= BWH_HeaderSize &&
4209          "Expected header size to be reserved");
4210   unsigned BCOffset = BWH_HeaderSize;
4211   unsigned BCSize = Buffer.size() - BWH_HeaderSize;
4212 
4213   // Write the magic and version.
4214   unsigned Position = 0;
4215   writeInt32ToBuffer(0x0B17C0DE, Buffer, Position);
4216   writeInt32ToBuffer(0, Buffer, Position); // Version.
4217   writeInt32ToBuffer(BCOffset, Buffer, Position);
4218   writeInt32ToBuffer(BCSize, Buffer, Position);
4219   writeInt32ToBuffer(CPUType, Buffer, Position);
4220 
4221   // If the file is not a multiple of 16 bytes, insert dummy padding.
4222   while (Buffer.size() & 15)
4223     Buffer.push_back(0);
4224 }
4225 
4226 /// Helper to write the header common to all bitcode files.
4227 static void writeBitcodeHeader(BitstreamWriter &Stream) {
4228   // Emit the file header.
4229   Stream.Emit((unsigned)'B', 8);
4230   Stream.Emit((unsigned)'C', 8);
4231   Stream.Emit(0x0, 4);
4232   Stream.Emit(0xC, 4);
4233   Stream.Emit(0xE, 4);
4234   Stream.Emit(0xD, 4);
4235 }
4236 
4237 BitcodeWriter::BitcodeWriter(SmallVectorImpl<char> &Buffer)
4238     : Buffer(Buffer), Stream(new BitstreamWriter(Buffer)) {
4239   writeBitcodeHeader(*Stream);
4240 }
4241 
4242 BitcodeWriter::~BitcodeWriter() { assert(WroteStrtab); }
4243 
4244 void BitcodeWriter::writeBlob(unsigned Block, unsigned Record, StringRef Blob) {
4245   Stream->EnterSubblock(Block, 3);
4246 
4247   auto Abbv = std::make_shared<BitCodeAbbrev>();
4248   Abbv->Add(BitCodeAbbrevOp(Record));
4249   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
4250   auto AbbrevNo = Stream->EmitAbbrev(std::move(Abbv));
4251 
4252   Stream->EmitRecordWithBlob(AbbrevNo, ArrayRef<uint64_t>{Record}, Blob);
4253 
4254   Stream->ExitBlock();
4255 }
4256 
4257 void BitcodeWriter::writeSymtab() {
4258   assert(!WroteStrtab && !WroteSymtab);
4259 
4260   // If any module has module-level inline asm, we will require a registered asm
4261   // parser for the target so that we can create an accurate symbol table for
4262   // the module.
4263   for (Module *M : Mods) {
4264     if (M->getModuleInlineAsm().empty())
4265       continue;
4266 
4267     std::string Err;
4268     const Triple TT(M->getTargetTriple());
4269     const Target *T = TargetRegistry::lookupTarget(TT.str(), Err);
4270     if (!T || !T->hasMCAsmParser())
4271       return;
4272   }
4273 
4274   WroteSymtab = true;
4275   SmallVector<char, 0> Symtab;
4276   // The irsymtab::build function may be unable to create a symbol table if the
4277   // module is malformed (e.g. it contains an invalid alias). Writing a symbol
4278   // table is not required for correctness, but we still want to be able to
4279   // write malformed modules to bitcode files, so swallow the error.
4280   if (Error E = irsymtab::build(Mods, Symtab, StrtabBuilder, Alloc)) {
4281     consumeError(std::move(E));
4282     return;
4283   }
4284 
4285   writeBlob(bitc::SYMTAB_BLOCK_ID, bitc::SYMTAB_BLOB,
4286             {Symtab.data(), Symtab.size()});
4287 }
4288 
4289 void BitcodeWriter::writeStrtab() {
4290   assert(!WroteStrtab);
4291 
4292   std::vector<char> Strtab;
4293   StrtabBuilder.finalizeInOrder();
4294   Strtab.resize(StrtabBuilder.getSize());
4295   StrtabBuilder.write((uint8_t *)Strtab.data());
4296 
4297   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB,
4298             {Strtab.data(), Strtab.size()});
4299 
4300   WroteStrtab = true;
4301 }
4302 
4303 void BitcodeWriter::copyStrtab(StringRef Strtab) {
4304   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB, Strtab);
4305   WroteStrtab = true;
4306 }
4307 
4308 void BitcodeWriter::writeModule(const Module &M,
4309                                 bool ShouldPreserveUseListOrder,
4310                                 const ModuleSummaryIndex *Index,
4311                                 bool GenerateHash, ModuleHash *ModHash) {
4312   assert(!WroteStrtab);
4313 
4314   // The Mods vector is used by irsymtab::build, which requires non-const
4315   // Modules in case it needs to materialize metadata. But the bitcode writer
4316   // requires that the module is materialized, so we can cast to non-const here,
4317   // after checking that it is in fact materialized.
4318   assert(M.isMaterialized());
4319   Mods.push_back(const_cast<Module *>(&M));
4320 
4321   ModuleBitcodeWriter ModuleWriter(M, Buffer, StrtabBuilder, *Stream,
4322                                    ShouldPreserveUseListOrder, Index,
4323                                    GenerateHash, ModHash);
4324   ModuleWriter.write();
4325 }
4326 
4327 void BitcodeWriter::writeIndex(
4328     const ModuleSummaryIndex *Index,
4329     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4330   IndexBitcodeWriter IndexWriter(*Stream, StrtabBuilder, *Index,
4331                                  ModuleToSummariesForIndex);
4332   IndexWriter.write();
4333 }
4334 
4335 /// Write the specified module to the specified output stream.
4336 void llvm::WriteBitcodeToFile(const Module &M, raw_ostream &Out,
4337                               bool ShouldPreserveUseListOrder,
4338                               const ModuleSummaryIndex *Index,
4339                               bool GenerateHash, ModuleHash *ModHash) {
4340   SmallVector<char, 0> Buffer;
4341   Buffer.reserve(256*1024);
4342 
4343   // If this is darwin or another generic macho target, reserve space for the
4344   // header.
4345   Triple TT(M.getTargetTriple());
4346   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4347     Buffer.insert(Buffer.begin(), BWH_HeaderSize, 0);
4348 
4349   BitcodeWriter Writer(Buffer);
4350   Writer.writeModule(M, ShouldPreserveUseListOrder, Index, GenerateHash,
4351                      ModHash);
4352   Writer.writeSymtab();
4353   Writer.writeStrtab();
4354 
4355   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4356     emitDarwinBCHeaderAndTrailer(Buffer, TT);
4357 
4358   // Write the generated bitstream to "Out".
4359   Out.write((char*)&Buffer.front(), Buffer.size());
4360 }
4361 
4362 void IndexBitcodeWriter::write() {
4363   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4364 
4365   writeModuleVersion();
4366 
4367   // Write the module paths in the combined index.
4368   writeModStrings();
4369 
4370   // Write the summary combined index records.
4371   writeCombinedGlobalValueSummary();
4372 
4373   Stream.ExitBlock();
4374 }
4375 
4376 // Write the specified module summary index to the given raw output stream,
4377 // where it will be written in a new bitcode block. This is used when
4378 // writing the combined index file for ThinLTO. When writing a subset of the
4379 // index for a distributed backend, provide a \p ModuleToSummariesForIndex map.
4380 void llvm::WriteIndexToFile(
4381     const ModuleSummaryIndex &Index, raw_ostream &Out,
4382     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4383   SmallVector<char, 0> Buffer;
4384   Buffer.reserve(256 * 1024);
4385 
4386   BitcodeWriter Writer(Buffer);
4387   Writer.writeIndex(&Index, ModuleToSummariesForIndex);
4388   Writer.writeStrtab();
4389 
4390   Out.write((char *)&Buffer.front(), Buffer.size());
4391 }
4392 
4393 namespace {
4394 
4395 /// Class to manage the bitcode writing for a thin link bitcode file.
4396 class ThinLinkBitcodeWriter : public ModuleBitcodeWriterBase {
4397   /// ModHash is for use in ThinLTO incremental build, generated while writing
4398   /// the module bitcode file.
4399   const ModuleHash *ModHash;
4400 
4401 public:
4402   ThinLinkBitcodeWriter(const Module &M, StringTableBuilder &StrtabBuilder,
4403                         BitstreamWriter &Stream,
4404                         const ModuleSummaryIndex &Index,
4405                         const ModuleHash &ModHash)
4406       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
4407                                 /*ShouldPreserveUseListOrder=*/false, &Index),
4408         ModHash(&ModHash) {}
4409 
4410   void write();
4411 
4412 private:
4413   void writeSimplifiedModuleInfo();
4414 };
4415 
4416 } // end anonymous namespace
4417 
4418 // This function writes a simpilified module info for thin link bitcode file.
4419 // It only contains the source file name along with the name(the offset and
4420 // size in strtab) and linkage for global values. For the global value info
4421 // entry, in order to keep linkage at offset 5, there are three zeros used
4422 // as padding.
4423 void ThinLinkBitcodeWriter::writeSimplifiedModuleInfo() {
4424   SmallVector<unsigned, 64> Vals;
4425   // Emit the module's source file name.
4426   {
4427     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
4428     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
4429     if (Bits == SE_Char6)
4430       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
4431     else if (Bits == SE_Fixed7)
4432       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
4433 
4434     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
4435     auto Abbv = std::make_shared<BitCodeAbbrev>();
4436     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
4437     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4438     Abbv->Add(AbbrevOpToUse);
4439     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4440 
4441     for (const auto P : M.getSourceFileName())
4442       Vals.push_back((unsigned char)P);
4443 
4444     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
4445     Vals.clear();
4446   }
4447 
4448   // Emit the global variable information.
4449   for (const GlobalVariable &GV : M.globals()) {
4450     // GLOBALVAR: [strtab offset, strtab size, 0, 0, 0, linkage]
4451     Vals.push_back(StrtabBuilder.add(GV.getName()));
4452     Vals.push_back(GV.getName().size());
4453     Vals.push_back(0);
4454     Vals.push_back(0);
4455     Vals.push_back(0);
4456     Vals.push_back(getEncodedLinkage(GV));
4457 
4458     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals);
4459     Vals.clear();
4460   }
4461 
4462   // Emit the function proto information.
4463   for (const Function &F : M) {
4464     // FUNCTION:  [strtab offset, strtab size, 0, 0, 0, linkage]
4465     Vals.push_back(StrtabBuilder.add(F.getName()));
4466     Vals.push_back(F.getName().size());
4467     Vals.push_back(0);
4468     Vals.push_back(0);
4469     Vals.push_back(0);
4470     Vals.push_back(getEncodedLinkage(F));
4471 
4472     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals);
4473     Vals.clear();
4474   }
4475 
4476   // Emit the alias information.
4477   for (const GlobalAlias &A : M.aliases()) {
4478     // ALIAS: [strtab offset, strtab size, 0, 0, 0, linkage]
4479     Vals.push_back(StrtabBuilder.add(A.getName()));
4480     Vals.push_back(A.getName().size());
4481     Vals.push_back(0);
4482     Vals.push_back(0);
4483     Vals.push_back(0);
4484     Vals.push_back(getEncodedLinkage(A));
4485 
4486     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals);
4487     Vals.clear();
4488   }
4489 
4490   // Emit the ifunc information.
4491   for (const GlobalIFunc &I : M.ifuncs()) {
4492     // IFUNC: [strtab offset, strtab size, 0, 0, 0, linkage]
4493     Vals.push_back(StrtabBuilder.add(I.getName()));
4494     Vals.push_back(I.getName().size());
4495     Vals.push_back(0);
4496     Vals.push_back(0);
4497     Vals.push_back(0);
4498     Vals.push_back(getEncodedLinkage(I));
4499 
4500     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
4501     Vals.clear();
4502   }
4503 }
4504 
4505 void ThinLinkBitcodeWriter::write() {
4506   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4507 
4508   writeModuleVersion();
4509 
4510   writeSimplifiedModuleInfo();
4511 
4512   writePerModuleGlobalValueSummary();
4513 
4514   // Write module hash.
4515   Stream.EmitRecord(bitc::MODULE_CODE_HASH, ArrayRef<uint32_t>(*ModHash));
4516 
4517   Stream.ExitBlock();
4518 }
4519 
4520 void BitcodeWriter::writeThinLinkBitcode(const Module &M,
4521                                          const ModuleSummaryIndex &Index,
4522                                          const ModuleHash &ModHash) {
4523   assert(!WroteStrtab);
4524 
4525   // The Mods vector is used by irsymtab::build, which requires non-const
4526   // Modules in case it needs to materialize metadata. But the bitcode writer
4527   // requires that the module is materialized, so we can cast to non-const here,
4528   // after checking that it is in fact materialized.
4529   assert(M.isMaterialized());
4530   Mods.push_back(const_cast<Module *>(&M));
4531 
4532   ThinLinkBitcodeWriter ThinLinkWriter(M, StrtabBuilder, *Stream, Index,
4533                                        ModHash);
4534   ThinLinkWriter.write();
4535 }
4536 
4537 // Write the specified thin link bitcode file to the given raw output stream,
4538 // where it will be written in a new bitcode block. This is used when
4539 // writing the per-module index file for ThinLTO.
4540 void llvm::WriteThinLinkBitcodeToFile(const Module &M, raw_ostream &Out,
4541                                       const ModuleSummaryIndex &Index,
4542                                       const ModuleHash &ModHash) {
4543   SmallVector<char, 0> Buffer;
4544   Buffer.reserve(256 * 1024);
4545 
4546   BitcodeWriter Writer(Buffer);
4547   Writer.writeThinLinkBitcode(M, Index, ModHash);
4548   Writer.writeSymtab();
4549   Writer.writeStrtab();
4550 
4551   Out.write((char *)&Buffer.front(), Buffer.size());
4552 }
4553