xref: /llvm-project/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp (revision 2dea3f129878e929e5d1f00b91a622eb1ec8be4e)
1 //===- Bitcode/Writer/BitcodeWriter.cpp - Bitcode Writer ------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // Bitcode writer implementation.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "llvm/Bitcode/BitcodeWriter.h"
14 #include "ValueEnumerator.h"
15 #include "llvm/ADT/APFloat.h"
16 #include "llvm/ADT/APInt.h"
17 #include "llvm/ADT/ArrayRef.h"
18 #include "llvm/ADT/DenseMap.h"
19 #include "llvm/ADT/None.h"
20 #include "llvm/ADT/Optional.h"
21 #include "llvm/ADT/STLExtras.h"
22 #include "llvm/ADT/SmallString.h"
23 #include "llvm/ADT/SmallVector.h"
24 #include "llvm/ADT/StringMap.h"
25 #include "llvm/ADT/StringRef.h"
26 #include "llvm/ADT/Triple.h"
27 #include "llvm/Bitcode/BitcodeReader.h"
28 #include "llvm/Bitcode/LLVMBitCodes.h"
29 #include "llvm/Bitstream/BitCodes.h"
30 #include "llvm/Bitstream/BitstreamWriter.h"
31 #include "llvm/Config/llvm-config.h"
32 #include "llvm/IR/Attributes.h"
33 #include "llvm/IR/BasicBlock.h"
34 #include "llvm/IR/CallSite.h"
35 #include "llvm/IR/Comdat.h"
36 #include "llvm/IR/Constant.h"
37 #include "llvm/IR/Constants.h"
38 #include "llvm/IR/DebugInfoMetadata.h"
39 #include "llvm/IR/DebugLoc.h"
40 #include "llvm/IR/DerivedTypes.h"
41 #include "llvm/IR/Function.h"
42 #include "llvm/IR/GlobalAlias.h"
43 #include "llvm/IR/GlobalIFunc.h"
44 #include "llvm/IR/GlobalObject.h"
45 #include "llvm/IR/GlobalValue.h"
46 #include "llvm/IR/GlobalVariable.h"
47 #include "llvm/IR/InlineAsm.h"
48 #include "llvm/IR/InstrTypes.h"
49 #include "llvm/IR/Instruction.h"
50 #include "llvm/IR/Instructions.h"
51 #include "llvm/IR/LLVMContext.h"
52 #include "llvm/IR/Metadata.h"
53 #include "llvm/IR/Module.h"
54 #include "llvm/IR/ModuleSummaryIndex.h"
55 #include "llvm/IR/Operator.h"
56 #include "llvm/IR/Type.h"
57 #include "llvm/IR/UseListOrder.h"
58 #include "llvm/IR/Value.h"
59 #include "llvm/IR/ValueSymbolTable.h"
60 #include "llvm/MC/StringTableBuilder.h"
61 #include "llvm/Object/IRSymtab.h"
62 #include "llvm/Support/AtomicOrdering.h"
63 #include "llvm/Support/Casting.h"
64 #include "llvm/Support/CommandLine.h"
65 #include "llvm/Support/Endian.h"
66 #include "llvm/Support/Error.h"
67 #include "llvm/Support/ErrorHandling.h"
68 #include "llvm/Support/MathExtras.h"
69 #include "llvm/Support/SHA1.h"
70 #include "llvm/Support/TargetRegistry.h"
71 #include "llvm/Support/raw_ostream.h"
72 #include <algorithm>
73 #include <cassert>
74 #include <cstddef>
75 #include <cstdint>
76 #include <iterator>
77 #include <map>
78 #include <memory>
79 #include <string>
80 #include <utility>
81 #include <vector>
82 
83 using namespace llvm;
84 
85 static cl::opt<unsigned>
86     IndexThreshold("bitcode-mdindex-threshold", cl::Hidden, cl::init(25),
87                    cl::desc("Number of metadatas above which we emit an index "
88                             "to enable lazy-loading"));
89 
90 static cl::opt<bool> WriteRelBFToSummary(
91     "write-relbf-to-summary", cl::Hidden, cl::init(false),
92     cl::desc("Write relative block frequency to function summary "));
93 
94 extern FunctionSummary::ForceSummaryHotnessType ForceSummaryEdgesCold;
95 
96 namespace {
97 
98 /// These are manifest constants used by the bitcode writer. They do not need to
99 /// be kept in sync with the reader, but need to be consistent within this file.
100 enum {
101   // VALUE_SYMTAB_BLOCK abbrev id's.
102   VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
103   VST_ENTRY_7_ABBREV,
104   VST_ENTRY_6_ABBREV,
105   VST_BBENTRY_6_ABBREV,
106 
107   // CONSTANTS_BLOCK abbrev id's.
108   CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
109   CONSTANTS_INTEGER_ABBREV,
110   CONSTANTS_CE_CAST_Abbrev,
111   CONSTANTS_NULL_Abbrev,
112 
113   // FUNCTION_BLOCK abbrev id's.
114   FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
115   FUNCTION_INST_UNOP_ABBREV,
116   FUNCTION_INST_UNOP_FLAGS_ABBREV,
117   FUNCTION_INST_BINOP_ABBREV,
118   FUNCTION_INST_BINOP_FLAGS_ABBREV,
119   FUNCTION_INST_CAST_ABBREV,
120   FUNCTION_INST_RET_VOID_ABBREV,
121   FUNCTION_INST_RET_VAL_ABBREV,
122   FUNCTION_INST_UNREACHABLE_ABBREV,
123   FUNCTION_INST_GEP_ABBREV,
124 };
125 
126 /// Abstract class to manage the bitcode writing, subclassed for each bitcode
127 /// file type.
128 class BitcodeWriterBase {
129 protected:
130   /// The stream created and owned by the client.
131   BitstreamWriter &Stream;
132 
133   StringTableBuilder &StrtabBuilder;
134 
135 public:
136   /// Constructs a BitcodeWriterBase object that writes to the provided
137   /// \p Stream.
138   BitcodeWriterBase(BitstreamWriter &Stream, StringTableBuilder &StrtabBuilder)
139       : Stream(Stream), StrtabBuilder(StrtabBuilder) {}
140 
141 protected:
142   void writeBitcodeHeader();
143   void writeModuleVersion();
144 };
145 
146 void BitcodeWriterBase::writeModuleVersion() {
147   // VERSION: [version#]
148   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, ArrayRef<uint64_t>{2});
149 }
150 
151 /// Base class to manage the module bitcode writing, currently subclassed for
152 /// ModuleBitcodeWriter and ThinLinkBitcodeWriter.
153 class ModuleBitcodeWriterBase : public BitcodeWriterBase {
154 protected:
155   /// The Module to write to bitcode.
156   const Module &M;
157 
158   /// Enumerates ids for all values in the module.
159   ValueEnumerator VE;
160 
161   /// Optional per-module index to write for ThinLTO.
162   const ModuleSummaryIndex *Index;
163 
164   /// Map that holds the correspondence between GUIDs in the summary index,
165   /// that came from indirect call profiles, and a value id generated by this
166   /// class to use in the VST and summary block records.
167   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
168 
169   /// Tracks the last value id recorded in the GUIDToValueMap.
170   unsigned GlobalValueId;
171 
172   /// Saves the offset of the VSTOffset record that must eventually be
173   /// backpatched with the offset of the actual VST.
174   uint64_t VSTOffsetPlaceholder = 0;
175 
176 public:
177   /// Constructs a ModuleBitcodeWriterBase object for the given Module,
178   /// writing to the provided \p Buffer.
179   ModuleBitcodeWriterBase(const Module &M, StringTableBuilder &StrtabBuilder,
180                           BitstreamWriter &Stream,
181                           bool ShouldPreserveUseListOrder,
182                           const ModuleSummaryIndex *Index)
183       : BitcodeWriterBase(Stream, StrtabBuilder), M(M),
184         VE(M, ShouldPreserveUseListOrder), Index(Index) {
185     // Assign ValueIds to any callee values in the index that came from
186     // indirect call profiles and were recorded as a GUID not a Value*
187     // (which would have been assigned an ID by the ValueEnumerator).
188     // The starting ValueId is just after the number of values in the
189     // ValueEnumerator, so that they can be emitted in the VST.
190     GlobalValueId = VE.getValues().size();
191     if (!Index)
192       return;
193     for (const auto &GUIDSummaryLists : *Index)
194       // Examine all summaries for this GUID.
195       for (auto &Summary : GUIDSummaryLists.second.SummaryList)
196         if (auto FS = dyn_cast<FunctionSummary>(Summary.get()))
197           // For each call in the function summary, see if the call
198           // is to a GUID (which means it is for an indirect call,
199           // otherwise we would have a Value for it). If so, synthesize
200           // a value id.
201           for (auto &CallEdge : FS->calls())
202             if (!CallEdge.first.haveGVs() || !CallEdge.first.getValue())
203               assignValueId(CallEdge.first.getGUID());
204   }
205 
206 protected:
207   void writePerModuleGlobalValueSummary();
208 
209 private:
210   void writePerModuleFunctionSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
211                                            GlobalValueSummary *Summary,
212                                            unsigned ValueID,
213                                            unsigned FSCallsAbbrev,
214                                            unsigned FSCallsProfileAbbrev,
215                                            const Function &F);
216   void writeModuleLevelReferences(const GlobalVariable &V,
217                                   SmallVector<uint64_t, 64> &NameVals,
218                                   unsigned FSModRefsAbbrev,
219                                   unsigned FSModVTableRefsAbbrev);
220 
221   void assignValueId(GlobalValue::GUID ValGUID) {
222     GUIDToValueIdMap[ValGUID] = ++GlobalValueId;
223   }
224 
225   unsigned getValueId(GlobalValue::GUID ValGUID) {
226     const auto &VMI = GUIDToValueIdMap.find(ValGUID);
227     // Expect that any GUID value had a value Id assigned by an
228     // earlier call to assignValueId.
229     assert(VMI != GUIDToValueIdMap.end() &&
230            "GUID does not have assigned value Id");
231     return VMI->second;
232   }
233 
234   // Helper to get the valueId for the type of value recorded in VI.
235   unsigned getValueId(ValueInfo VI) {
236     if (!VI.haveGVs() || !VI.getValue())
237       return getValueId(VI.getGUID());
238     return VE.getValueID(VI.getValue());
239   }
240 
241   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
242 };
243 
244 /// Class to manage the bitcode writing for a module.
245 class ModuleBitcodeWriter : public ModuleBitcodeWriterBase {
246   /// Pointer to the buffer allocated by caller for bitcode writing.
247   const SmallVectorImpl<char> &Buffer;
248 
249   /// True if a module hash record should be written.
250   bool GenerateHash;
251 
252   /// If non-null, when GenerateHash is true, the resulting hash is written
253   /// into ModHash.
254   ModuleHash *ModHash;
255 
256   SHA1 Hasher;
257 
258   /// The start bit of the identification block.
259   uint64_t BitcodeStartBit;
260 
261 public:
262   /// Constructs a ModuleBitcodeWriter object for the given Module,
263   /// writing to the provided \p Buffer.
264   ModuleBitcodeWriter(const Module &M, SmallVectorImpl<char> &Buffer,
265                       StringTableBuilder &StrtabBuilder,
266                       BitstreamWriter &Stream, bool ShouldPreserveUseListOrder,
267                       const ModuleSummaryIndex *Index, bool GenerateHash,
268                       ModuleHash *ModHash = nullptr)
269       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
270                                 ShouldPreserveUseListOrder, Index),
271         Buffer(Buffer), GenerateHash(GenerateHash), ModHash(ModHash),
272         BitcodeStartBit(Stream.GetCurrentBitNo()) {}
273 
274   /// Emit the current module to the bitstream.
275   void write();
276 
277 private:
278   uint64_t bitcodeStartBit() { return BitcodeStartBit; }
279 
280   size_t addToStrtab(StringRef Str);
281 
282   void writeAttributeGroupTable();
283   void writeAttributeTable();
284   void writeTypeTable();
285   void writeComdats();
286   void writeValueSymbolTableForwardDecl();
287   void writeModuleInfo();
288   void writeValueAsMetadata(const ValueAsMetadata *MD,
289                             SmallVectorImpl<uint64_t> &Record);
290   void writeMDTuple(const MDTuple *N, SmallVectorImpl<uint64_t> &Record,
291                     unsigned Abbrev);
292   unsigned createDILocationAbbrev();
293   void writeDILocation(const DILocation *N, SmallVectorImpl<uint64_t> &Record,
294                        unsigned &Abbrev);
295   unsigned createGenericDINodeAbbrev();
296   void writeGenericDINode(const GenericDINode *N,
297                           SmallVectorImpl<uint64_t> &Record, unsigned &Abbrev);
298   void writeDISubrange(const DISubrange *N, SmallVectorImpl<uint64_t> &Record,
299                        unsigned Abbrev);
300   void writeDIEnumerator(const DIEnumerator *N,
301                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
302   void writeDIBasicType(const DIBasicType *N, SmallVectorImpl<uint64_t> &Record,
303                         unsigned Abbrev);
304   void writeDIDerivedType(const DIDerivedType *N,
305                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
306   void writeDICompositeType(const DICompositeType *N,
307                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
308   void writeDISubroutineType(const DISubroutineType *N,
309                              SmallVectorImpl<uint64_t> &Record,
310                              unsigned Abbrev);
311   void writeDIFile(const DIFile *N, SmallVectorImpl<uint64_t> &Record,
312                    unsigned Abbrev);
313   void writeDICompileUnit(const DICompileUnit *N,
314                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
315   void writeDISubprogram(const DISubprogram *N,
316                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
317   void writeDILexicalBlock(const DILexicalBlock *N,
318                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
319   void writeDILexicalBlockFile(const DILexicalBlockFile *N,
320                                SmallVectorImpl<uint64_t> &Record,
321                                unsigned Abbrev);
322   void writeDICommonBlock(const DICommonBlock *N,
323                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
324   void writeDINamespace(const DINamespace *N, SmallVectorImpl<uint64_t> &Record,
325                         unsigned Abbrev);
326   void writeDIMacro(const DIMacro *N, SmallVectorImpl<uint64_t> &Record,
327                     unsigned Abbrev);
328   void writeDIMacroFile(const DIMacroFile *N, SmallVectorImpl<uint64_t> &Record,
329                         unsigned Abbrev);
330   void writeDIModule(const DIModule *N, SmallVectorImpl<uint64_t> &Record,
331                      unsigned Abbrev);
332   void writeDITemplateTypeParameter(const DITemplateTypeParameter *N,
333                                     SmallVectorImpl<uint64_t> &Record,
334                                     unsigned Abbrev);
335   void writeDITemplateValueParameter(const DITemplateValueParameter *N,
336                                      SmallVectorImpl<uint64_t> &Record,
337                                      unsigned Abbrev);
338   void writeDIGlobalVariable(const DIGlobalVariable *N,
339                              SmallVectorImpl<uint64_t> &Record,
340                              unsigned Abbrev);
341   void writeDILocalVariable(const DILocalVariable *N,
342                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
343   void writeDILabel(const DILabel *N,
344                     SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
345   void writeDIExpression(const DIExpression *N,
346                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
347   void writeDIGlobalVariableExpression(const DIGlobalVariableExpression *N,
348                                        SmallVectorImpl<uint64_t> &Record,
349                                        unsigned Abbrev);
350   void writeDIObjCProperty(const DIObjCProperty *N,
351                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
352   void writeDIImportedEntity(const DIImportedEntity *N,
353                              SmallVectorImpl<uint64_t> &Record,
354                              unsigned Abbrev);
355   unsigned createNamedMetadataAbbrev();
356   void writeNamedMetadata(SmallVectorImpl<uint64_t> &Record);
357   unsigned createMetadataStringsAbbrev();
358   void writeMetadataStrings(ArrayRef<const Metadata *> Strings,
359                             SmallVectorImpl<uint64_t> &Record);
360   void writeMetadataRecords(ArrayRef<const Metadata *> MDs,
361                             SmallVectorImpl<uint64_t> &Record,
362                             std::vector<unsigned> *MDAbbrevs = nullptr,
363                             std::vector<uint64_t> *IndexPos = nullptr);
364   void writeModuleMetadata();
365   void writeFunctionMetadata(const Function &F);
366   void writeFunctionMetadataAttachment(const Function &F);
367   void writeGlobalVariableMetadataAttachment(const GlobalVariable &GV);
368   void pushGlobalMetadataAttachment(SmallVectorImpl<uint64_t> &Record,
369                                     const GlobalObject &GO);
370   void writeModuleMetadataKinds();
371   void writeOperandBundleTags();
372   void writeSyncScopeNames();
373   void writeConstants(unsigned FirstVal, unsigned LastVal, bool isGlobal);
374   void writeModuleConstants();
375   bool pushValueAndType(const Value *V, unsigned InstID,
376                         SmallVectorImpl<unsigned> &Vals);
377   void writeOperandBundles(ImmutableCallSite CS, unsigned InstID);
378   void pushValue(const Value *V, unsigned InstID,
379                  SmallVectorImpl<unsigned> &Vals);
380   void pushValueSigned(const Value *V, unsigned InstID,
381                        SmallVectorImpl<uint64_t> &Vals);
382   void writeInstruction(const Instruction &I, unsigned InstID,
383                         SmallVectorImpl<unsigned> &Vals);
384   void writeFunctionLevelValueSymbolTable(const ValueSymbolTable &VST);
385   void writeGlobalValueSymbolTable(
386       DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
387   void writeUseList(UseListOrder &&Order);
388   void writeUseListBlock(const Function *F);
389   void
390   writeFunction(const Function &F,
391                 DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
392   void writeBlockInfo();
393   void writeModuleHash(size_t BlockStartPos);
394 
395   unsigned getEncodedSyncScopeID(SyncScope::ID SSID) {
396     return unsigned(SSID);
397   }
398 };
399 
400 /// Class to manage the bitcode writing for a combined index.
401 class IndexBitcodeWriter : public BitcodeWriterBase {
402   /// The combined index to write to bitcode.
403   const ModuleSummaryIndex &Index;
404 
405   /// When writing a subset of the index for distributed backends, client
406   /// provides a map of modules to the corresponding GUIDs/summaries to write.
407   const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex;
408 
409   /// Map that holds the correspondence between the GUID used in the combined
410   /// index and a value id generated by this class to use in references.
411   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
412 
413   /// Tracks the last value id recorded in the GUIDToValueMap.
414   unsigned GlobalValueId = 0;
415 
416 public:
417   /// Constructs a IndexBitcodeWriter object for the given combined index,
418   /// writing to the provided \p Buffer. When writing a subset of the index
419   /// for a distributed backend, provide a \p ModuleToSummariesForIndex map.
420   IndexBitcodeWriter(BitstreamWriter &Stream, StringTableBuilder &StrtabBuilder,
421                      const ModuleSummaryIndex &Index,
422                      const std::map<std::string, GVSummaryMapTy>
423                          *ModuleToSummariesForIndex = nullptr)
424       : BitcodeWriterBase(Stream, StrtabBuilder), Index(Index),
425         ModuleToSummariesForIndex(ModuleToSummariesForIndex) {
426     // Assign unique value ids to all summaries to be written, for use
427     // in writing out the call graph edges. Save the mapping from GUID
428     // to the new global value id to use when writing those edges, which
429     // are currently saved in the index in terms of GUID.
430     forEachSummary([&](GVInfo I, bool) {
431       GUIDToValueIdMap[I.first] = ++GlobalValueId;
432     });
433   }
434 
435   /// The below iterator returns the GUID and associated summary.
436   using GVInfo = std::pair<GlobalValue::GUID, GlobalValueSummary *>;
437 
438   /// Calls the callback for each value GUID and summary to be written to
439   /// bitcode. This hides the details of whether they are being pulled from the
440   /// entire index or just those in a provided ModuleToSummariesForIndex map.
441   template<typename Functor>
442   void forEachSummary(Functor Callback) {
443     if (ModuleToSummariesForIndex) {
444       for (auto &M : *ModuleToSummariesForIndex)
445         for (auto &Summary : M.second) {
446           Callback(Summary, false);
447           // Ensure aliasee is handled, e.g. for assigning a valueId,
448           // even if we are not importing the aliasee directly (the
449           // imported alias will contain a copy of aliasee).
450           if (auto *AS = dyn_cast<AliasSummary>(Summary.getSecond()))
451             Callback({AS->getAliaseeGUID(), &AS->getAliasee()}, true);
452         }
453     } else {
454       for (auto &Summaries : Index)
455         for (auto &Summary : Summaries.second.SummaryList)
456           Callback({Summaries.first, Summary.get()}, false);
457     }
458   }
459 
460   /// Calls the callback for each entry in the modulePaths StringMap that
461   /// should be written to the module path string table. This hides the details
462   /// of whether they are being pulled from the entire index or just those in a
463   /// provided ModuleToSummariesForIndex map.
464   template <typename Functor> void forEachModule(Functor Callback) {
465     if (ModuleToSummariesForIndex) {
466       for (const auto &M : *ModuleToSummariesForIndex) {
467         const auto &MPI = Index.modulePaths().find(M.first);
468         if (MPI == Index.modulePaths().end()) {
469           // This should only happen if the bitcode file was empty, in which
470           // case we shouldn't be importing (the ModuleToSummariesForIndex
471           // would only include the module we are writing and index for).
472           assert(ModuleToSummariesForIndex->size() == 1);
473           continue;
474         }
475         Callback(*MPI);
476       }
477     } else {
478       for (const auto &MPSE : Index.modulePaths())
479         Callback(MPSE);
480     }
481   }
482 
483   /// Main entry point for writing a combined index to bitcode.
484   void write();
485 
486 private:
487   void writeModStrings();
488   void writeCombinedGlobalValueSummary();
489 
490   Optional<unsigned> getValueId(GlobalValue::GUID ValGUID) {
491     auto VMI = GUIDToValueIdMap.find(ValGUID);
492     if (VMI == GUIDToValueIdMap.end())
493       return None;
494     return VMI->second;
495   }
496 
497   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
498 };
499 
500 } // end anonymous namespace
501 
502 static unsigned getEncodedCastOpcode(unsigned Opcode) {
503   switch (Opcode) {
504   default: llvm_unreachable("Unknown cast instruction!");
505   case Instruction::Trunc   : return bitc::CAST_TRUNC;
506   case Instruction::ZExt    : return bitc::CAST_ZEXT;
507   case Instruction::SExt    : return bitc::CAST_SEXT;
508   case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
509   case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
510   case Instruction::UIToFP  : return bitc::CAST_UITOFP;
511   case Instruction::SIToFP  : return bitc::CAST_SITOFP;
512   case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
513   case Instruction::FPExt   : return bitc::CAST_FPEXT;
514   case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
515   case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
516   case Instruction::BitCast : return bitc::CAST_BITCAST;
517   case Instruction::AddrSpaceCast: return bitc::CAST_ADDRSPACECAST;
518   }
519 }
520 
521 static unsigned getEncodedUnaryOpcode(unsigned Opcode) {
522   switch (Opcode) {
523   default: llvm_unreachable("Unknown binary instruction!");
524   case Instruction::FNeg: return bitc::UNOP_FNEG;
525   }
526 }
527 
528 static unsigned getEncodedBinaryOpcode(unsigned Opcode) {
529   switch (Opcode) {
530   default: llvm_unreachable("Unknown binary instruction!");
531   case Instruction::Add:
532   case Instruction::FAdd: return bitc::BINOP_ADD;
533   case Instruction::Sub:
534   case Instruction::FSub: return bitc::BINOP_SUB;
535   case Instruction::Mul:
536   case Instruction::FMul: return bitc::BINOP_MUL;
537   case Instruction::UDiv: return bitc::BINOP_UDIV;
538   case Instruction::FDiv:
539   case Instruction::SDiv: return bitc::BINOP_SDIV;
540   case Instruction::URem: return bitc::BINOP_UREM;
541   case Instruction::FRem:
542   case Instruction::SRem: return bitc::BINOP_SREM;
543   case Instruction::Shl:  return bitc::BINOP_SHL;
544   case Instruction::LShr: return bitc::BINOP_LSHR;
545   case Instruction::AShr: return bitc::BINOP_ASHR;
546   case Instruction::And:  return bitc::BINOP_AND;
547   case Instruction::Or:   return bitc::BINOP_OR;
548   case Instruction::Xor:  return bitc::BINOP_XOR;
549   }
550 }
551 
552 static unsigned getEncodedRMWOperation(AtomicRMWInst::BinOp Op) {
553   switch (Op) {
554   default: llvm_unreachable("Unknown RMW operation!");
555   case AtomicRMWInst::Xchg: return bitc::RMW_XCHG;
556   case AtomicRMWInst::Add: return bitc::RMW_ADD;
557   case AtomicRMWInst::Sub: return bitc::RMW_SUB;
558   case AtomicRMWInst::And: return bitc::RMW_AND;
559   case AtomicRMWInst::Nand: return bitc::RMW_NAND;
560   case AtomicRMWInst::Or: return bitc::RMW_OR;
561   case AtomicRMWInst::Xor: return bitc::RMW_XOR;
562   case AtomicRMWInst::Max: return bitc::RMW_MAX;
563   case AtomicRMWInst::Min: return bitc::RMW_MIN;
564   case AtomicRMWInst::UMax: return bitc::RMW_UMAX;
565   case AtomicRMWInst::UMin: return bitc::RMW_UMIN;
566   case AtomicRMWInst::FAdd: return bitc::RMW_FADD;
567   case AtomicRMWInst::FSub: return bitc::RMW_FSUB;
568   }
569 }
570 
571 static unsigned getEncodedOrdering(AtomicOrdering Ordering) {
572   switch (Ordering) {
573   case AtomicOrdering::NotAtomic: return bitc::ORDERING_NOTATOMIC;
574   case AtomicOrdering::Unordered: return bitc::ORDERING_UNORDERED;
575   case AtomicOrdering::Monotonic: return bitc::ORDERING_MONOTONIC;
576   case AtomicOrdering::Acquire: return bitc::ORDERING_ACQUIRE;
577   case AtomicOrdering::Release: return bitc::ORDERING_RELEASE;
578   case AtomicOrdering::AcquireRelease: return bitc::ORDERING_ACQREL;
579   case AtomicOrdering::SequentiallyConsistent: return bitc::ORDERING_SEQCST;
580   }
581   llvm_unreachable("Invalid ordering");
582 }
583 
584 static void writeStringRecord(BitstreamWriter &Stream, unsigned Code,
585                               StringRef Str, unsigned AbbrevToUse) {
586   SmallVector<unsigned, 64> Vals;
587 
588   // Code: [strchar x N]
589   for (unsigned i = 0, e = Str.size(); i != e; ++i) {
590     if (AbbrevToUse && !BitCodeAbbrevOp::isChar6(Str[i]))
591       AbbrevToUse = 0;
592     Vals.push_back(Str[i]);
593   }
594 
595   // Emit the finished record.
596   Stream.EmitRecord(Code, Vals, AbbrevToUse);
597 }
598 
599 static uint64_t getAttrKindEncoding(Attribute::AttrKind Kind) {
600   switch (Kind) {
601   case Attribute::Alignment:
602     return bitc::ATTR_KIND_ALIGNMENT;
603   case Attribute::AllocSize:
604     return bitc::ATTR_KIND_ALLOC_SIZE;
605   case Attribute::AlwaysInline:
606     return bitc::ATTR_KIND_ALWAYS_INLINE;
607   case Attribute::ArgMemOnly:
608     return bitc::ATTR_KIND_ARGMEMONLY;
609   case Attribute::Builtin:
610     return bitc::ATTR_KIND_BUILTIN;
611   case Attribute::ByVal:
612     return bitc::ATTR_KIND_BY_VAL;
613   case Attribute::Convergent:
614     return bitc::ATTR_KIND_CONVERGENT;
615   case Attribute::InAlloca:
616     return bitc::ATTR_KIND_IN_ALLOCA;
617   case Attribute::Cold:
618     return bitc::ATTR_KIND_COLD;
619   case Attribute::InaccessibleMemOnly:
620     return bitc::ATTR_KIND_INACCESSIBLEMEM_ONLY;
621   case Attribute::InaccessibleMemOrArgMemOnly:
622     return bitc::ATTR_KIND_INACCESSIBLEMEM_OR_ARGMEMONLY;
623   case Attribute::InlineHint:
624     return bitc::ATTR_KIND_INLINE_HINT;
625   case Attribute::InReg:
626     return bitc::ATTR_KIND_IN_REG;
627   case Attribute::JumpTable:
628     return bitc::ATTR_KIND_JUMP_TABLE;
629   case Attribute::MinSize:
630     return bitc::ATTR_KIND_MIN_SIZE;
631   case Attribute::Naked:
632     return bitc::ATTR_KIND_NAKED;
633   case Attribute::Nest:
634     return bitc::ATTR_KIND_NEST;
635   case Attribute::NoAlias:
636     return bitc::ATTR_KIND_NO_ALIAS;
637   case Attribute::NoBuiltin:
638     return bitc::ATTR_KIND_NO_BUILTIN;
639   case Attribute::NoCapture:
640     return bitc::ATTR_KIND_NO_CAPTURE;
641   case Attribute::NoDuplicate:
642     return bitc::ATTR_KIND_NO_DUPLICATE;
643   case Attribute::NoFree:
644     return bitc::ATTR_KIND_NOFREE;
645   case Attribute::NoImplicitFloat:
646     return bitc::ATTR_KIND_NO_IMPLICIT_FLOAT;
647   case Attribute::NoInline:
648     return bitc::ATTR_KIND_NO_INLINE;
649   case Attribute::NoRecurse:
650     return bitc::ATTR_KIND_NO_RECURSE;
651   case Attribute::NonLazyBind:
652     return bitc::ATTR_KIND_NON_LAZY_BIND;
653   case Attribute::NonNull:
654     return bitc::ATTR_KIND_NON_NULL;
655   case Attribute::Dereferenceable:
656     return bitc::ATTR_KIND_DEREFERENCEABLE;
657   case Attribute::DereferenceableOrNull:
658     return bitc::ATTR_KIND_DEREFERENCEABLE_OR_NULL;
659   case Attribute::NoRedZone:
660     return bitc::ATTR_KIND_NO_RED_ZONE;
661   case Attribute::NoReturn:
662     return bitc::ATTR_KIND_NO_RETURN;
663   case Attribute::NoSync:
664     return bitc::ATTR_KIND_NOSYNC;
665   case Attribute::NoCfCheck:
666     return bitc::ATTR_KIND_NOCF_CHECK;
667   case Attribute::NoUnwind:
668     return bitc::ATTR_KIND_NO_UNWIND;
669   case Attribute::OptForFuzzing:
670     return bitc::ATTR_KIND_OPT_FOR_FUZZING;
671   case Attribute::OptimizeForSize:
672     return bitc::ATTR_KIND_OPTIMIZE_FOR_SIZE;
673   case Attribute::OptimizeNone:
674     return bitc::ATTR_KIND_OPTIMIZE_NONE;
675   case Attribute::ReadNone:
676     return bitc::ATTR_KIND_READ_NONE;
677   case Attribute::ReadOnly:
678     return bitc::ATTR_KIND_READ_ONLY;
679   case Attribute::Returned:
680     return bitc::ATTR_KIND_RETURNED;
681   case Attribute::ReturnsTwice:
682     return bitc::ATTR_KIND_RETURNS_TWICE;
683   case Attribute::SExt:
684     return bitc::ATTR_KIND_S_EXT;
685   case Attribute::Speculatable:
686     return bitc::ATTR_KIND_SPECULATABLE;
687   case Attribute::StackAlignment:
688     return bitc::ATTR_KIND_STACK_ALIGNMENT;
689   case Attribute::StackProtect:
690     return bitc::ATTR_KIND_STACK_PROTECT;
691   case Attribute::StackProtectReq:
692     return bitc::ATTR_KIND_STACK_PROTECT_REQ;
693   case Attribute::StackProtectStrong:
694     return bitc::ATTR_KIND_STACK_PROTECT_STRONG;
695   case Attribute::SafeStack:
696     return bitc::ATTR_KIND_SAFESTACK;
697   case Attribute::ShadowCallStack:
698     return bitc::ATTR_KIND_SHADOWCALLSTACK;
699   case Attribute::StrictFP:
700     return bitc::ATTR_KIND_STRICT_FP;
701   case Attribute::StructRet:
702     return bitc::ATTR_KIND_STRUCT_RET;
703   case Attribute::SanitizeAddress:
704     return bitc::ATTR_KIND_SANITIZE_ADDRESS;
705   case Attribute::SanitizeHWAddress:
706     return bitc::ATTR_KIND_SANITIZE_HWADDRESS;
707   case Attribute::SanitizeThread:
708     return bitc::ATTR_KIND_SANITIZE_THREAD;
709   case Attribute::SanitizeMemory:
710     return bitc::ATTR_KIND_SANITIZE_MEMORY;
711   case Attribute::SpeculativeLoadHardening:
712     return bitc::ATTR_KIND_SPECULATIVE_LOAD_HARDENING;
713   case Attribute::SwiftError:
714     return bitc::ATTR_KIND_SWIFT_ERROR;
715   case Attribute::SwiftSelf:
716     return bitc::ATTR_KIND_SWIFT_SELF;
717   case Attribute::UWTable:
718     return bitc::ATTR_KIND_UW_TABLE;
719   case Attribute::WillReturn:
720     return bitc::ATTR_KIND_WILLRETURN;
721   case Attribute::WriteOnly:
722     return bitc::ATTR_KIND_WRITEONLY;
723   case Attribute::ZExt:
724     return bitc::ATTR_KIND_Z_EXT;
725   case Attribute::ImmArg:
726     return bitc::ATTR_KIND_IMMARG;
727   case Attribute::SanitizeMemTag:
728     return bitc::ATTR_KIND_SANITIZE_MEMTAG;
729   case Attribute::EndAttrKinds:
730     llvm_unreachable("Can not encode end-attribute kinds marker.");
731   case Attribute::None:
732     llvm_unreachable("Can not encode none-attribute.");
733   case Attribute::EmptyKey:
734   case Attribute::TombstoneKey:
735     llvm_unreachable("Trying to encode EmptyKey/TombstoneKey");
736   }
737 
738   llvm_unreachable("Trying to encode unknown attribute");
739 }
740 
741 void ModuleBitcodeWriter::writeAttributeGroupTable() {
742   const std::vector<ValueEnumerator::IndexAndAttrSet> &AttrGrps =
743       VE.getAttributeGroups();
744   if (AttrGrps.empty()) return;
745 
746   Stream.EnterSubblock(bitc::PARAMATTR_GROUP_BLOCK_ID, 3);
747 
748   SmallVector<uint64_t, 64> Record;
749   for (ValueEnumerator::IndexAndAttrSet Pair : AttrGrps) {
750     unsigned AttrListIndex = Pair.first;
751     AttributeSet AS = Pair.second;
752     Record.push_back(VE.getAttributeGroupID(Pair));
753     Record.push_back(AttrListIndex);
754 
755     for (Attribute Attr : AS) {
756       if (Attr.isEnumAttribute()) {
757         Record.push_back(0);
758         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
759       } else if (Attr.isIntAttribute()) {
760         Record.push_back(1);
761         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
762         Record.push_back(Attr.getValueAsInt());
763       } else if (Attr.isStringAttribute()) {
764         StringRef Kind = Attr.getKindAsString();
765         StringRef Val = Attr.getValueAsString();
766 
767         Record.push_back(Val.empty() ? 3 : 4);
768         Record.append(Kind.begin(), Kind.end());
769         Record.push_back(0);
770         if (!Val.empty()) {
771           Record.append(Val.begin(), Val.end());
772           Record.push_back(0);
773         }
774       } else {
775         assert(Attr.isTypeAttribute());
776         Type *Ty = Attr.getValueAsType();
777         Record.push_back(Ty ? 6 : 5);
778         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
779         if (Ty)
780           Record.push_back(VE.getTypeID(Attr.getValueAsType()));
781       }
782     }
783 
784     Stream.EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
785     Record.clear();
786   }
787 
788   Stream.ExitBlock();
789 }
790 
791 void ModuleBitcodeWriter::writeAttributeTable() {
792   const std::vector<AttributeList> &Attrs = VE.getAttributeLists();
793   if (Attrs.empty()) return;
794 
795   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
796 
797   SmallVector<uint64_t, 64> Record;
798   for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
799     AttributeList AL = Attrs[i];
800     for (unsigned i = AL.index_begin(), e = AL.index_end(); i != e; ++i) {
801       AttributeSet AS = AL.getAttributes(i);
802       if (AS.hasAttributes())
803         Record.push_back(VE.getAttributeGroupID({i, AS}));
804     }
805 
806     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
807     Record.clear();
808   }
809 
810   Stream.ExitBlock();
811 }
812 
813 /// WriteTypeTable - Write out the type table for a module.
814 void ModuleBitcodeWriter::writeTypeTable() {
815   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
816 
817   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
818   SmallVector<uint64_t, 64> TypeVals;
819 
820   uint64_t NumBits = VE.computeBitsRequiredForTypeIndicies();
821 
822   // Abbrev for TYPE_CODE_POINTER.
823   auto Abbv = std::make_shared<BitCodeAbbrev>();
824   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
825   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
826   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
827   unsigned PtrAbbrev = Stream.EmitAbbrev(std::move(Abbv));
828 
829   // Abbrev for TYPE_CODE_FUNCTION.
830   Abbv = std::make_shared<BitCodeAbbrev>();
831   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
832   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
833   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
834   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
835   unsigned FunctionAbbrev = Stream.EmitAbbrev(std::move(Abbv));
836 
837   // Abbrev for TYPE_CODE_STRUCT_ANON.
838   Abbv = std::make_shared<BitCodeAbbrev>();
839   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
840   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
841   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
842   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
843   unsigned StructAnonAbbrev = Stream.EmitAbbrev(std::move(Abbv));
844 
845   // Abbrev for TYPE_CODE_STRUCT_NAME.
846   Abbv = std::make_shared<BitCodeAbbrev>();
847   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
848   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
849   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
850   unsigned StructNameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
851 
852   // Abbrev for TYPE_CODE_STRUCT_NAMED.
853   Abbv = std::make_shared<BitCodeAbbrev>();
854   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
855   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
856   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
857   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
858   unsigned StructNamedAbbrev = Stream.EmitAbbrev(std::move(Abbv));
859 
860   // Abbrev for TYPE_CODE_ARRAY.
861   Abbv = std::make_shared<BitCodeAbbrev>();
862   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
863   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
864   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
865   unsigned ArrayAbbrev = Stream.EmitAbbrev(std::move(Abbv));
866 
867   // Emit an entry count so the reader can reserve space.
868   TypeVals.push_back(TypeList.size());
869   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
870   TypeVals.clear();
871 
872   // Loop over all of the types, emitting each in turn.
873   for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
874     Type *T = TypeList[i];
875     int AbbrevToUse = 0;
876     unsigned Code = 0;
877 
878     switch (T->getTypeID()) {
879     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;      break;
880     case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;      break;
881     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;     break;
882     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE;    break;
883     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80;  break;
884     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128;     break;
885     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
886     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;     break;
887     case Type::MetadataTyID:  Code = bitc::TYPE_CODE_METADATA;  break;
888     case Type::X86_MMXTyID:   Code = bitc::TYPE_CODE_X86_MMX;   break;
889     case Type::TokenTyID:     Code = bitc::TYPE_CODE_TOKEN;     break;
890     case Type::IntegerTyID:
891       // INTEGER: [width]
892       Code = bitc::TYPE_CODE_INTEGER;
893       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
894       break;
895     case Type::PointerTyID: {
896       PointerType *PTy = cast<PointerType>(T);
897       // POINTER: [pointee type, address space]
898       Code = bitc::TYPE_CODE_POINTER;
899       TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
900       unsigned AddressSpace = PTy->getAddressSpace();
901       TypeVals.push_back(AddressSpace);
902       if (AddressSpace == 0) AbbrevToUse = PtrAbbrev;
903       break;
904     }
905     case Type::FunctionTyID: {
906       FunctionType *FT = cast<FunctionType>(T);
907       // FUNCTION: [isvararg, retty, paramty x N]
908       Code = bitc::TYPE_CODE_FUNCTION;
909       TypeVals.push_back(FT->isVarArg());
910       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
911       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
912         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
913       AbbrevToUse = FunctionAbbrev;
914       break;
915     }
916     case Type::StructTyID: {
917       StructType *ST = cast<StructType>(T);
918       // STRUCT: [ispacked, eltty x N]
919       TypeVals.push_back(ST->isPacked());
920       // Output all of the element types.
921       for (StructType::element_iterator I = ST->element_begin(),
922            E = ST->element_end(); I != E; ++I)
923         TypeVals.push_back(VE.getTypeID(*I));
924 
925       if (ST->isLiteral()) {
926         Code = bitc::TYPE_CODE_STRUCT_ANON;
927         AbbrevToUse = StructAnonAbbrev;
928       } else {
929         if (ST->isOpaque()) {
930           Code = bitc::TYPE_CODE_OPAQUE;
931         } else {
932           Code = bitc::TYPE_CODE_STRUCT_NAMED;
933           AbbrevToUse = StructNamedAbbrev;
934         }
935 
936         // Emit the name if it is present.
937         if (!ST->getName().empty())
938           writeStringRecord(Stream, bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
939                             StructNameAbbrev);
940       }
941       break;
942     }
943     case Type::ArrayTyID: {
944       ArrayType *AT = cast<ArrayType>(T);
945       // ARRAY: [numelts, eltty]
946       Code = bitc::TYPE_CODE_ARRAY;
947       TypeVals.push_back(AT->getNumElements());
948       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
949       AbbrevToUse = ArrayAbbrev;
950       break;
951     }
952     case Type::FixedVectorTyID:
953     case Type::ScalableVectorTyID: {
954       VectorType *VT = cast<VectorType>(T);
955       // VECTOR [numelts, eltty] or
956       //        [numelts, eltty, scalable]
957       Code = bitc::TYPE_CODE_VECTOR;
958       TypeVals.push_back(VT->getNumElements());
959       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
960       if (VT->isScalable())
961         TypeVals.push_back(VT->isScalable());
962       break;
963     }
964     }
965 
966     // Emit the finished record.
967     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
968     TypeVals.clear();
969   }
970 
971   Stream.ExitBlock();
972 }
973 
974 static unsigned getEncodedLinkage(const GlobalValue::LinkageTypes Linkage) {
975   switch (Linkage) {
976   case GlobalValue::ExternalLinkage:
977     return 0;
978   case GlobalValue::WeakAnyLinkage:
979     return 16;
980   case GlobalValue::AppendingLinkage:
981     return 2;
982   case GlobalValue::InternalLinkage:
983     return 3;
984   case GlobalValue::LinkOnceAnyLinkage:
985     return 18;
986   case GlobalValue::ExternalWeakLinkage:
987     return 7;
988   case GlobalValue::CommonLinkage:
989     return 8;
990   case GlobalValue::PrivateLinkage:
991     return 9;
992   case GlobalValue::WeakODRLinkage:
993     return 17;
994   case GlobalValue::LinkOnceODRLinkage:
995     return 19;
996   case GlobalValue::AvailableExternallyLinkage:
997     return 12;
998   }
999   llvm_unreachable("Invalid linkage");
1000 }
1001 
1002 static unsigned getEncodedLinkage(const GlobalValue &GV) {
1003   return getEncodedLinkage(GV.getLinkage());
1004 }
1005 
1006 static uint64_t getEncodedFFlags(FunctionSummary::FFlags Flags) {
1007   uint64_t RawFlags = 0;
1008   RawFlags |= Flags.ReadNone;
1009   RawFlags |= (Flags.ReadOnly << 1);
1010   RawFlags |= (Flags.NoRecurse << 2);
1011   RawFlags |= (Flags.ReturnDoesNotAlias << 3);
1012   RawFlags |= (Flags.NoInline << 4);
1013   RawFlags |= (Flags.AlwaysInline << 5);
1014   return RawFlags;
1015 }
1016 
1017 // Decode the flags for GlobalValue in the summary
1018 static uint64_t getEncodedGVSummaryFlags(GlobalValueSummary::GVFlags Flags) {
1019   uint64_t RawFlags = 0;
1020 
1021   RawFlags |= Flags.NotEligibleToImport; // bool
1022   RawFlags |= (Flags.Live << 1);
1023   RawFlags |= (Flags.DSOLocal << 2);
1024   RawFlags |= (Flags.CanAutoHide << 3);
1025 
1026   // Linkage don't need to be remapped at that time for the summary. Any future
1027   // change to the getEncodedLinkage() function will need to be taken into
1028   // account here as well.
1029   RawFlags = (RawFlags << 4) | Flags.Linkage; // 4 bits
1030 
1031   return RawFlags;
1032 }
1033 
1034 static uint64_t getEncodedGVarFlags(GlobalVarSummary::GVarFlags Flags) {
1035   uint64_t RawFlags = Flags.MaybeReadOnly | (Flags.MaybeWriteOnly << 1) |
1036                       (Flags.Constant << 2) | Flags.VCallVisibility << 3;
1037   return RawFlags;
1038 }
1039 
1040 static unsigned getEncodedVisibility(const GlobalValue &GV) {
1041   switch (GV.getVisibility()) {
1042   case GlobalValue::DefaultVisibility:   return 0;
1043   case GlobalValue::HiddenVisibility:    return 1;
1044   case GlobalValue::ProtectedVisibility: return 2;
1045   }
1046   llvm_unreachable("Invalid visibility");
1047 }
1048 
1049 static unsigned getEncodedDLLStorageClass(const GlobalValue &GV) {
1050   switch (GV.getDLLStorageClass()) {
1051   case GlobalValue::DefaultStorageClass:   return 0;
1052   case GlobalValue::DLLImportStorageClass: return 1;
1053   case GlobalValue::DLLExportStorageClass: return 2;
1054   }
1055   llvm_unreachable("Invalid DLL storage class");
1056 }
1057 
1058 static unsigned getEncodedThreadLocalMode(const GlobalValue &GV) {
1059   switch (GV.getThreadLocalMode()) {
1060     case GlobalVariable::NotThreadLocal:         return 0;
1061     case GlobalVariable::GeneralDynamicTLSModel: return 1;
1062     case GlobalVariable::LocalDynamicTLSModel:   return 2;
1063     case GlobalVariable::InitialExecTLSModel:    return 3;
1064     case GlobalVariable::LocalExecTLSModel:      return 4;
1065   }
1066   llvm_unreachable("Invalid TLS model");
1067 }
1068 
1069 static unsigned getEncodedComdatSelectionKind(const Comdat &C) {
1070   switch (C.getSelectionKind()) {
1071   case Comdat::Any:
1072     return bitc::COMDAT_SELECTION_KIND_ANY;
1073   case Comdat::ExactMatch:
1074     return bitc::COMDAT_SELECTION_KIND_EXACT_MATCH;
1075   case Comdat::Largest:
1076     return bitc::COMDAT_SELECTION_KIND_LARGEST;
1077   case Comdat::NoDuplicates:
1078     return bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES;
1079   case Comdat::SameSize:
1080     return bitc::COMDAT_SELECTION_KIND_SAME_SIZE;
1081   }
1082   llvm_unreachable("Invalid selection kind");
1083 }
1084 
1085 static unsigned getEncodedUnnamedAddr(const GlobalValue &GV) {
1086   switch (GV.getUnnamedAddr()) {
1087   case GlobalValue::UnnamedAddr::None:   return 0;
1088   case GlobalValue::UnnamedAddr::Local:  return 2;
1089   case GlobalValue::UnnamedAddr::Global: return 1;
1090   }
1091   llvm_unreachable("Invalid unnamed_addr");
1092 }
1093 
1094 size_t ModuleBitcodeWriter::addToStrtab(StringRef Str) {
1095   if (GenerateHash)
1096     Hasher.update(Str);
1097   return StrtabBuilder.add(Str);
1098 }
1099 
1100 void ModuleBitcodeWriter::writeComdats() {
1101   SmallVector<unsigned, 64> Vals;
1102   for (const Comdat *C : VE.getComdats()) {
1103     // COMDAT: [strtab offset, strtab size, selection_kind]
1104     Vals.push_back(addToStrtab(C->getName()));
1105     Vals.push_back(C->getName().size());
1106     Vals.push_back(getEncodedComdatSelectionKind(*C));
1107     Stream.EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
1108     Vals.clear();
1109   }
1110 }
1111 
1112 /// Write a record that will eventually hold the word offset of the
1113 /// module-level VST. For now the offset is 0, which will be backpatched
1114 /// after the real VST is written. Saves the bit offset to backpatch.
1115 void ModuleBitcodeWriter::writeValueSymbolTableForwardDecl() {
1116   // Write a placeholder value in for the offset of the real VST,
1117   // which is written after the function blocks so that it can include
1118   // the offset of each function. The placeholder offset will be
1119   // updated when the real VST is written.
1120   auto Abbv = std::make_shared<BitCodeAbbrev>();
1121   Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_VSTOFFSET));
1122   // Blocks are 32-bit aligned, so we can use a 32-bit word offset to
1123   // hold the real VST offset. Must use fixed instead of VBR as we don't
1124   // know how many VBR chunks to reserve ahead of time.
1125   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
1126   unsigned VSTOffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1127 
1128   // Emit the placeholder
1129   uint64_t Vals[] = {bitc::MODULE_CODE_VSTOFFSET, 0};
1130   Stream.EmitRecordWithAbbrev(VSTOffsetAbbrev, Vals);
1131 
1132   // Compute and save the bit offset to the placeholder, which will be
1133   // patched when the real VST is written. We can simply subtract the 32-bit
1134   // fixed size from the current bit number to get the location to backpatch.
1135   VSTOffsetPlaceholder = Stream.GetCurrentBitNo() - 32;
1136 }
1137 
1138 enum StringEncoding { SE_Char6, SE_Fixed7, SE_Fixed8 };
1139 
1140 /// Determine the encoding to use for the given string name and length.
1141 static StringEncoding getStringEncoding(StringRef Str) {
1142   bool isChar6 = true;
1143   for (char C : Str) {
1144     if (isChar6)
1145       isChar6 = BitCodeAbbrevOp::isChar6(C);
1146     if ((unsigned char)C & 128)
1147       // don't bother scanning the rest.
1148       return SE_Fixed8;
1149   }
1150   if (isChar6)
1151     return SE_Char6;
1152   return SE_Fixed7;
1153 }
1154 
1155 /// Emit top-level description of module, including target triple, inline asm,
1156 /// descriptors for global variables, and function prototype info.
1157 /// Returns the bit offset to backpatch with the location of the real VST.
1158 void ModuleBitcodeWriter::writeModuleInfo() {
1159   // Emit various pieces of data attached to a module.
1160   if (!M.getTargetTriple().empty())
1161     writeStringRecord(Stream, bitc::MODULE_CODE_TRIPLE, M.getTargetTriple(),
1162                       0 /*TODO*/);
1163   const std::string &DL = M.getDataLayoutStr();
1164   if (!DL.empty())
1165     writeStringRecord(Stream, bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/);
1166   if (!M.getModuleInlineAsm().empty())
1167     writeStringRecord(Stream, bitc::MODULE_CODE_ASM, M.getModuleInlineAsm(),
1168                       0 /*TODO*/);
1169 
1170   // Emit information about sections and GC, computing how many there are. Also
1171   // compute the maximum alignment value.
1172   std::map<std::string, unsigned> SectionMap;
1173   std::map<std::string, unsigned> GCMap;
1174   unsigned MaxAlignment = 0;
1175   unsigned MaxGlobalType = 0;
1176   for (const GlobalValue &GV : M.globals()) {
1177     MaxAlignment = std::max(MaxAlignment, GV.getAlignment());
1178     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getValueType()));
1179     if (GV.hasSection()) {
1180       // Give section names unique ID's.
1181       unsigned &Entry = SectionMap[std::string(GV.getSection())];
1182       if (!Entry) {
1183         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
1184                           0 /*TODO*/);
1185         Entry = SectionMap.size();
1186       }
1187     }
1188   }
1189   for (const Function &F : M) {
1190     MaxAlignment = std::max(MaxAlignment, F.getAlignment());
1191     if (F.hasSection()) {
1192       // Give section names unique ID's.
1193       unsigned &Entry = SectionMap[std::string(F.getSection())];
1194       if (!Entry) {
1195         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
1196                           0 /*TODO*/);
1197         Entry = SectionMap.size();
1198       }
1199     }
1200     if (F.hasGC()) {
1201       // Same for GC names.
1202       unsigned &Entry = GCMap[F.getGC()];
1203       if (!Entry) {
1204         writeStringRecord(Stream, bitc::MODULE_CODE_GCNAME, F.getGC(),
1205                           0 /*TODO*/);
1206         Entry = GCMap.size();
1207       }
1208     }
1209   }
1210 
1211   // Emit abbrev for globals, now that we know # sections and max alignment.
1212   unsigned SimpleGVarAbbrev = 0;
1213   if (!M.global_empty()) {
1214     // Add an abbrev for common globals with no visibility or thread localness.
1215     auto Abbv = std::make_shared<BitCodeAbbrev>();
1216     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
1217     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1218     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1219     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1220                               Log2_32_Ceil(MaxGlobalType+1)));
1221     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddrSpace << 2
1222                                                            //| explicitType << 1
1223                                                            //| constant
1224     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Initializer.
1225     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // Linkage.
1226     if (MaxAlignment == 0)                                 // Alignment.
1227       Abbv->Add(BitCodeAbbrevOp(0));
1228     else {
1229       unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
1230       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1231                                Log2_32_Ceil(MaxEncAlignment+1)));
1232     }
1233     if (SectionMap.empty())                                    // Section.
1234       Abbv->Add(BitCodeAbbrevOp(0));
1235     else
1236       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1237                                Log2_32_Ceil(SectionMap.size()+1)));
1238     // Don't bother emitting vis + thread local.
1239     SimpleGVarAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1240   }
1241 
1242   SmallVector<unsigned, 64> Vals;
1243   // Emit the module's source file name.
1244   {
1245     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
1246     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
1247     if (Bits == SE_Char6)
1248       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
1249     else if (Bits == SE_Fixed7)
1250       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
1251 
1252     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
1253     auto Abbv = std::make_shared<BitCodeAbbrev>();
1254     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
1255     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1256     Abbv->Add(AbbrevOpToUse);
1257     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1258 
1259     for (const auto P : M.getSourceFileName())
1260       Vals.push_back((unsigned char)P);
1261 
1262     // Emit the finished record.
1263     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
1264     Vals.clear();
1265   }
1266 
1267   // Emit the global variable information.
1268   for (const GlobalVariable &GV : M.globals()) {
1269     unsigned AbbrevToUse = 0;
1270 
1271     // GLOBALVAR: [strtab offset, strtab size, type, isconst, initid,
1272     //             linkage, alignment, section, visibility, threadlocal,
1273     //             unnamed_addr, externally_initialized, dllstorageclass,
1274     //             comdat, attributes, DSO_Local]
1275     Vals.push_back(addToStrtab(GV.getName()));
1276     Vals.push_back(GV.getName().size());
1277     Vals.push_back(VE.getTypeID(GV.getValueType()));
1278     Vals.push_back(GV.getType()->getAddressSpace() << 2 | 2 | GV.isConstant());
1279     Vals.push_back(GV.isDeclaration() ? 0 :
1280                    (VE.getValueID(GV.getInitializer()) + 1));
1281     Vals.push_back(getEncodedLinkage(GV));
1282     Vals.push_back(Log2_32(GV.getAlignment())+1);
1283     Vals.push_back(GV.hasSection() ? SectionMap[std::string(GV.getSection())]
1284                                    : 0);
1285     if (GV.isThreadLocal() ||
1286         GV.getVisibility() != GlobalValue::DefaultVisibility ||
1287         GV.getUnnamedAddr() != GlobalValue::UnnamedAddr::None ||
1288         GV.isExternallyInitialized() ||
1289         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
1290         GV.hasComdat() ||
1291         GV.hasAttributes() ||
1292         GV.isDSOLocal() ||
1293         GV.hasPartition()) {
1294       Vals.push_back(getEncodedVisibility(GV));
1295       Vals.push_back(getEncodedThreadLocalMode(GV));
1296       Vals.push_back(getEncodedUnnamedAddr(GV));
1297       Vals.push_back(GV.isExternallyInitialized());
1298       Vals.push_back(getEncodedDLLStorageClass(GV));
1299       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
1300 
1301       auto AL = GV.getAttributesAsList(AttributeList::FunctionIndex);
1302       Vals.push_back(VE.getAttributeListID(AL));
1303 
1304       Vals.push_back(GV.isDSOLocal());
1305       Vals.push_back(addToStrtab(GV.getPartition()));
1306       Vals.push_back(GV.getPartition().size());
1307     } else {
1308       AbbrevToUse = SimpleGVarAbbrev;
1309     }
1310 
1311     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
1312     Vals.clear();
1313   }
1314 
1315   // Emit the function proto information.
1316   for (const Function &F : M) {
1317     // FUNCTION:  [strtab offset, strtab size, type, callingconv, isproto,
1318     //             linkage, paramattrs, alignment, section, visibility, gc,
1319     //             unnamed_addr, prologuedata, dllstorageclass, comdat,
1320     //             prefixdata, personalityfn, DSO_Local, addrspace]
1321     Vals.push_back(addToStrtab(F.getName()));
1322     Vals.push_back(F.getName().size());
1323     Vals.push_back(VE.getTypeID(F.getFunctionType()));
1324     Vals.push_back(F.getCallingConv());
1325     Vals.push_back(F.isDeclaration());
1326     Vals.push_back(getEncodedLinkage(F));
1327     Vals.push_back(VE.getAttributeListID(F.getAttributes()));
1328     Vals.push_back(Log2_32(F.getAlignment())+1);
1329     Vals.push_back(F.hasSection() ? SectionMap[std::string(F.getSection())]
1330                                   : 0);
1331     Vals.push_back(getEncodedVisibility(F));
1332     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
1333     Vals.push_back(getEncodedUnnamedAddr(F));
1334     Vals.push_back(F.hasPrologueData() ? (VE.getValueID(F.getPrologueData()) + 1)
1335                                        : 0);
1336     Vals.push_back(getEncodedDLLStorageClass(F));
1337     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
1338     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
1339                                      : 0);
1340     Vals.push_back(
1341         F.hasPersonalityFn() ? (VE.getValueID(F.getPersonalityFn()) + 1) : 0);
1342 
1343     Vals.push_back(F.isDSOLocal());
1344     Vals.push_back(F.getAddressSpace());
1345     Vals.push_back(addToStrtab(F.getPartition()));
1346     Vals.push_back(F.getPartition().size());
1347 
1348     unsigned AbbrevToUse = 0;
1349     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
1350     Vals.clear();
1351   }
1352 
1353   // Emit the alias information.
1354   for (const GlobalAlias &A : M.aliases()) {
1355     // ALIAS: [strtab offset, strtab size, alias type, aliasee val#, linkage,
1356     //         visibility, dllstorageclass, threadlocal, unnamed_addr,
1357     //         DSO_Local]
1358     Vals.push_back(addToStrtab(A.getName()));
1359     Vals.push_back(A.getName().size());
1360     Vals.push_back(VE.getTypeID(A.getValueType()));
1361     Vals.push_back(A.getType()->getAddressSpace());
1362     Vals.push_back(VE.getValueID(A.getAliasee()));
1363     Vals.push_back(getEncodedLinkage(A));
1364     Vals.push_back(getEncodedVisibility(A));
1365     Vals.push_back(getEncodedDLLStorageClass(A));
1366     Vals.push_back(getEncodedThreadLocalMode(A));
1367     Vals.push_back(getEncodedUnnamedAddr(A));
1368     Vals.push_back(A.isDSOLocal());
1369     Vals.push_back(addToStrtab(A.getPartition()));
1370     Vals.push_back(A.getPartition().size());
1371 
1372     unsigned AbbrevToUse = 0;
1373     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
1374     Vals.clear();
1375   }
1376 
1377   // Emit the ifunc information.
1378   for (const GlobalIFunc &I : M.ifuncs()) {
1379     // IFUNC: [strtab offset, strtab size, ifunc type, address space, resolver
1380     //         val#, linkage, visibility, DSO_Local]
1381     Vals.push_back(addToStrtab(I.getName()));
1382     Vals.push_back(I.getName().size());
1383     Vals.push_back(VE.getTypeID(I.getValueType()));
1384     Vals.push_back(I.getType()->getAddressSpace());
1385     Vals.push_back(VE.getValueID(I.getResolver()));
1386     Vals.push_back(getEncodedLinkage(I));
1387     Vals.push_back(getEncodedVisibility(I));
1388     Vals.push_back(I.isDSOLocal());
1389     Vals.push_back(addToStrtab(I.getPartition()));
1390     Vals.push_back(I.getPartition().size());
1391     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
1392     Vals.clear();
1393   }
1394 
1395   writeValueSymbolTableForwardDecl();
1396 }
1397 
1398 static uint64_t getOptimizationFlags(const Value *V) {
1399   uint64_t Flags = 0;
1400 
1401   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
1402     if (OBO->hasNoSignedWrap())
1403       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
1404     if (OBO->hasNoUnsignedWrap())
1405       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
1406   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
1407     if (PEO->isExact())
1408       Flags |= 1 << bitc::PEO_EXACT;
1409   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
1410     if (FPMO->hasAllowReassoc())
1411       Flags |= bitc::AllowReassoc;
1412     if (FPMO->hasNoNaNs())
1413       Flags |= bitc::NoNaNs;
1414     if (FPMO->hasNoInfs())
1415       Flags |= bitc::NoInfs;
1416     if (FPMO->hasNoSignedZeros())
1417       Flags |= bitc::NoSignedZeros;
1418     if (FPMO->hasAllowReciprocal())
1419       Flags |= bitc::AllowReciprocal;
1420     if (FPMO->hasAllowContract())
1421       Flags |= bitc::AllowContract;
1422     if (FPMO->hasApproxFunc())
1423       Flags |= bitc::ApproxFunc;
1424   }
1425 
1426   return Flags;
1427 }
1428 
1429 void ModuleBitcodeWriter::writeValueAsMetadata(
1430     const ValueAsMetadata *MD, SmallVectorImpl<uint64_t> &Record) {
1431   // Mimic an MDNode with a value as one operand.
1432   Value *V = MD->getValue();
1433   Record.push_back(VE.getTypeID(V->getType()));
1434   Record.push_back(VE.getValueID(V));
1435   Stream.EmitRecord(bitc::METADATA_VALUE, Record, 0);
1436   Record.clear();
1437 }
1438 
1439 void ModuleBitcodeWriter::writeMDTuple(const MDTuple *N,
1440                                        SmallVectorImpl<uint64_t> &Record,
1441                                        unsigned Abbrev) {
1442   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
1443     Metadata *MD = N->getOperand(i);
1444     assert(!(MD && isa<LocalAsMetadata>(MD)) &&
1445            "Unexpected function-local metadata");
1446     Record.push_back(VE.getMetadataOrNullID(MD));
1447   }
1448   Stream.EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
1449                                     : bitc::METADATA_NODE,
1450                     Record, Abbrev);
1451   Record.clear();
1452 }
1453 
1454 unsigned ModuleBitcodeWriter::createDILocationAbbrev() {
1455   // Assume the column is usually under 128, and always output the inlined-at
1456   // location (it's never more expensive than building an array size 1).
1457   auto Abbv = std::make_shared<BitCodeAbbrev>();
1458   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
1459   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1460   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1461   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1462   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1463   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1464   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1465   return Stream.EmitAbbrev(std::move(Abbv));
1466 }
1467 
1468 void ModuleBitcodeWriter::writeDILocation(const DILocation *N,
1469                                           SmallVectorImpl<uint64_t> &Record,
1470                                           unsigned &Abbrev) {
1471   if (!Abbrev)
1472     Abbrev = createDILocationAbbrev();
1473 
1474   Record.push_back(N->isDistinct());
1475   Record.push_back(N->getLine());
1476   Record.push_back(N->getColumn());
1477   Record.push_back(VE.getMetadataID(N->getScope()));
1478   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
1479   Record.push_back(N->isImplicitCode());
1480 
1481   Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
1482   Record.clear();
1483 }
1484 
1485 unsigned ModuleBitcodeWriter::createGenericDINodeAbbrev() {
1486   // Assume the column is usually under 128, and always output the inlined-at
1487   // location (it's never more expensive than building an array size 1).
1488   auto Abbv = std::make_shared<BitCodeAbbrev>();
1489   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
1490   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1491   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1492   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1493   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1494   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1495   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1496   return Stream.EmitAbbrev(std::move(Abbv));
1497 }
1498 
1499 void ModuleBitcodeWriter::writeGenericDINode(const GenericDINode *N,
1500                                              SmallVectorImpl<uint64_t> &Record,
1501                                              unsigned &Abbrev) {
1502   if (!Abbrev)
1503     Abbrev = createGenericDINodeAbbrev();
1504 
1505   Record.push_back(N->isDistinct());
1506   Record.push_back(N->getTag());
1507   Record.push_back(0); // Per-tag version field; unused for now.
1508 
1509   for (auto &I : N->operands())
1510     Record.push_back(VE.getMetadataOrNullID(I));
1511 
1512   Stream.EmitRecord(bitc::METADATA_GENERIC_DEBUG, Record, Abbrev);
1513   Record.clear();
1514 }
1515 
1516 static uint64_t rotateSign(int64_t I) {
1517   uint64_t U = I;
1518   return I < 0 ? ~(U << 1) : U << 1;
1519 }
1520 
1521 void ModuleBitcodeWriter::writeDISubrange(const DISubrange *N,
1522                                           SmallVectorImpl<uint64_t> &Record,
1523                                           unsigned Abbrev) {
1524   const uint64_t Version = 1 << 1;
1525   Record.push_back((uint64_t)N->isDistinct() | Version);
1526   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1527   Record.push_back(rotateSign(N->getLowerBound()));
1528 
1529   Stream.EmitRecord(bitc::METADATA_SUBRANGE, Record, Abbrev);
1530   Record.clear();
1531 }
1532 
1533 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
1534   if ((int64_t)V >= 0)
1535     Vals.push_back(V << 1);
1536   else
1537     Vals.push_back((-V << 1) | 1);
1538 }
1539 
1540 static void emitWideAPInt(SmallVectorImpl<uint64_t> &Vals, const APInt &A) {
1541   // We have an arbitrary precision integer value to write whose
1542   // bit width is > 64. However, in canonical unsigned integer
1543   // format it is likely that the high bits are going to be zero.
1544   // So, we only write the number of active words.
1545   unsigned NumWords = A.getActiveWords();
1546   const uint64_t *RawData = A.getRawData();
1547   for (unsigned i = 0; i < NumWords; i++)
1548     emitSignedInt64(Vals, RawData[i]);
1549 }
1550 
1551 void ModuleBitcodeWriter::writeDIEnumerator(const DIEnumerator *N,
1552                                             SmallVectorImpl<uint64_t> &Record,
1553                                             unsigned Abbrev) {
1554   const uint64_t IsBigInt = 1 << 2;
1555   Record.push_back(IsBigInt | (N->isUnsigned() << 1) | N->isDistinct());
1556   Record.push_back(N->getValue().getBitWidth());
1557   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1558   emitWideAPInt(Record, N->getValue());
1559 
1560   Stream.EmitRecord(bitc::METADATA_ENUMERATOR, Record, Abbrev);
1561   Record.clear();
1562 }
1563 
1564 void ModuleBitcodeWriter::writeDIBasicType(const DIBasicType *N,
1565                                            SmallVectorImpl<uint64_t> &Record,
1566                                            unsigned Abbrev) {
1567   Record.push_back(N->isDistinct());
1568   Record.push_back(N->getTag());
1569   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1570   Record.push_back(N->getSizeInBits());
1571   Record.push_back(N->getAlignInBits());
1572   Record.push_back(N->getEncoding());
1573   Record.push_back(N->getFlags());
1574 
1575   Stream.EmitRecord(bitc::METADATA_BASIC_TYPE, Record, Abbrev);
1576   Record.clear();
1577 }
1578 
1579 void ModuleBitcodeWriter::writeDIDerivedType(const DIDerivedType *N,
1580                                              SmallVectorImpl<uint64_t> &Record,
1581                                              unsigned Abbrev) {
1582   Record.push_back(N->isDistinct());
1583   Record.push_back(N->getTag());
1584   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1585   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1586   Record.push_back(N->getLine());
1587   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1588   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1589   Record.push_back(N->getSizeInBits());
1590   Record.push_back(N->getAlignInBits());
1591   Record.push_back(N->getOffsetInBits());
1592   Record.push_back(N->getFlags());
1593   Record.push_back(VE.getMetadataOrNullID(N->getExtraData()));
1594 
1595   // DWARF address space is encoded as N->getDWARFAddressSpace() + 1. 0 means
1596   // that there is no DWARF address space associated with DIDerivedType.
1597   if (const auto &DWARFAddressSpace = N->getDWARFAddressSpace())
1598     Record.push_back(*DWARFAddressSpace + 1);
1599   else
1600     Record.push_back(0);
1601 
1602   Stream.EmitRecord(bitc::METADATA_DERIVED_TYPE, Record, Abbrev);
1603   Record.clear();
1604 }
1605 
1606 void ModuleBitcodeWriter::writeDICompositeType(
1607     const DICompositeType *N, SmallVectorImpl<uint64_t> &Record,
1608     unsigned Abbrev) {
1609   const unsigned IsNotUsedInOldTypeRef = 0x2;
1610   Record.push_back(IsNotUsedInOldTypeRef | (unsigned)N->isDistinct());
1611   Record.push_back(N->getTag());
1612   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1613   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1614   Record.push_back(N->getLine());
1615   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1616   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1617   Record.push_back(N->getSizeInBits());
1618   Record.push_back(N->getAlignInBits());
1619   Record.push_back(N->getOffsetInBits());
1620   Record.push_back(N->getFlags());
1621   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1622   Record.push_back(N->getRuntimeLang());
1623   Record.push_back(VE.getMetadataOrNullID(N->getVTableHolder()));
1624   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1625   Record.push_back(VE.getMetadataOrNullID(N->getRawIdentifier()));
1626   Record.push_back(VE.getMetadataOrNullID(N->getDiscriminator()));
1627 
1628   Stream.EmitRecord(bitc::METADATA_COMPOSITE_TYPE, Record, Abbrev);
1629   Record.clear();
1630 }
1631 
1632 void ModuleBitcodeWriter::writeDISubroutineType(
1633     const DISubroutineType *N, SmallVectorImpl<uint64_t> &Record,
1634     unsigned Abbrev) {
1635   const unsigned HasNoOldTypeRefs = 0x2;
1636   Record.push_back(HasNoOldTypeRefs | (unsigned)N->isDistinct());
1637   Record.push_back(N->getFlags());
1638   Record.push_back(VE.getMetadataOrNullID(N->getTypeArray().get()));
1639   Record.push_back(N->getCC());
1640 
1641   Stream.EmitRecord(bitc::METADATA_SUBROUTINE_TYPE, Record, Abbrev);
1642   Record.clear();
1643 }
1644 
1645 void ModuleBitcodeWriter::writeDIFile(const DIFile *N,
1646                                       SmallVectorImpl<uint64_t> &Record,
1647                                       unsigned Abbrev) {
1648   Record.push_back(N->isDistinct());
1649   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
1650   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
1651   if (N->getRawChecksum()) {
1652     Record.push_back(N->getRawChecksum()->Kind);
1653     Record.push_back(VE.getMetadataOrNullID(N->getRawChecksum()->Value));
1654   } else {
1655     // Maintain backwards compatibility with the old internal representation of
1656     // CSK_None in ChecksumKind by writing nulls here when Checksum is None.
1657     Record.push_back(0);
1658     Record.push_back(VE.getMetadataOrNullID(nullptr));
1659   }
1660   auto Source = N->getRawSource();
1661   if (Source)
1662     Record.push_back(VE.getMetadataOrNullID(*Source));
1663 
1664   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
1665   Record.clear();
1666 }
1667 
1668 void ModuleBitcodeWriter::writeDICompileUnit(const DICompileUnit *N,
1669                                              SmallVectorImpl<uint64_t> &Record,
1670                                              unsigned Abbrev) {
1671   assert(N->isDistinct() && "Expected distinct compile units");
1672   Record.push_back(/* IsDistinct */ true);
1673   Record.push_back(N->getSourceLanguage());
1674   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1675   Record.push_back(VE.getMetadataOrNullID(N->getRawProducer()));
1676   Record.push_back(N->isOptimized());
1677   Record.push_back(VE.getMetadataOrNullID(N->getRawFlags()));
1678   Record.push_back(N->getRuntimeVersion());
1679   Record.push_back(VE.getMetadataOrNullID(N->getRawSplitDebugFilename()));
1680   Record.push_back(N->getEmissionKind());
1681   Record.push_back(VE.getMetadataOrNullID(N->getEnumTypes().get()));
1682   Record.push_back(VE.getMetadataOrNullID(N->getRetainedTypes().get()));
1683   Record.push_back(/* subprograms */ 0);
1684   Record.push_back(VE.getMetadataOrNullID(N->getGlobalVariables().get()));
1685   Record.push_back(VE.getMetadataOrNullID(N->getImportedEntities().get()));
1686   Record.push_back(N->getDWOId());
1687   Record.push_back(VE.getMetadataOrNullID(N->getMacros().get()));
1688   Record.push_back(N->getSplitDebugInlining());
1689   Record.push_back(N->getDebugInfoForProfiling());
1690   Record.push_back((unsigned)N->getNameTableKind());
1691   Record.push_back(N->getRangesBaseAddress());
1692   Record.push_back(VE.getMetadataOrNullID(N->getRawSysRoot()));
1693   Record.push_back(VE.getMetadataOrNullID(N->getRawSDK()));
1694 
1695   Stream.EmitRecord(bitc::METADATA_COMPILE_UNIT, Record, Abbrev);
1696   Record.clear();
1697 }
1698 
1699 void ModuleBitcodeWriter::writeDISubprogram(const DISubprogram *N,
1700                                             SmallVectorImpl<uint64_t> &Record,
1701                                             unsigned Abbrev) {
1702   const uint64_t HasUnitFlag = 1 << 1;
1703   const uint64_t HasSPFlagsFlag = 1 << 2;
1704   Record.push_back(uint64_t(N->isDistinct()) | HasUnitFlag | HasSPFlagsFlag);
1705   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1706   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1707   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1708   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1709   Record.push_back(N->getLine());
1710   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1711   Record.push_back(N->getScopeLine());
1712   Record.push_back(VE.getMetadataOrNullID(N->getContainingType()));
1713   Record.push_back(N->getSPFlags());
1714   Record.push_back(N->getVirtualIndex());
1715   Record.push_back(N->getFlags());
1716   Record.push_back(VE.getMetadataOrNullID(N->getRawUnit()));
1717   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1718   Record.push_back(VE.getMetadataOrNullID(N->getDeclaration()));
1719   Record.push_back(VE.getMetadataOrNullID(N->getRetainedNodes().get()));
1720   Record.push_back(N->getThisAdjustment());
1721   Record.push_back(VE.getMetadataOrNullID(N->getThrownTypes().get()));
1722 
1723   Stream.EmitRecord(bitc::METADATA_SUBPROGRAM, Record, Abbrev);
1724   Record.clear();
1725 }
1726 
1727 void ModuleBitcodeWriter::writeDILexicalBlock(const DILexicalBlock *N,
1728                                               SmallVectorImpl<uint64_t> &Record,
1729                                               unsigned Abbrev) {
1730   Record.push_back(N->isDistinct());
1731   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1732   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1733   Record.push_back(N->getLine());
1734   Record.push_back(N->getColumn());
1735 
1736   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK, Record, Abbrev);
1737   Record.clear();
1738 }
1739 
1740 void ModuleBitcodeWriter::writeDILexicalBlockFile(
1741     const DILexicalBlockFile *N, SmallVectorImpl<uint64_t> &Record,
1742     unsigned Abbrev) {
1743   Record.push_back(N->isDistinct());
1744   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1745   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1746   Record.push_back(N->getDiscriminator());
1747 
1748   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK_FILE, Record, Abbrev);
1749   Record.clear();
1750 }
1751 
1752 void ModuleBitcodeWriter::writeDICommonBlock(const DICommonBlock *N,
1753                                              SmallVectorImpl<uint64_t> &Record,
1754                                              unsigned Abbrev) {
1755   Record.push_back(N->isDistinct());
1756   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1757   Record.push_back(VE.getMetadataOrNullID(N->getDecl()));
1758   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1759   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1760   Record.push_back(N->getLineNo());
1761 
1762   Stream.EmitRecord(bitc::METADATA_COMMON_BLOCK, Record, Abbrev);
1763   Record.clear();
1764 }
1765 
1766 void ModuleBitcodeWriter::writeDINamespace(const DINamespace *N,
1767                                            SmallVectorImpl<uint64_t> &Record,
1768                                            unsigned Abbrev) {
1769   Record.push_back(N->isDistinct() | N->getExportSymbols() << 1);
1770   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1771   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1772 
1773   Stream.EmitRecord(bitc::METADATA_NAMESPACE, Record, Abbrev);
1774   Record.clear();
1775 }
1776 
1777 void ModuleBitcodeWriter::writeDIMacro(const DIMacro *N,
1778                                        SmallVectorImpl<uint64_t> &Record,
1779                                        unsigned Abbrev) {
1780   Record.push_back(N->isDistinct());
1781   Record.push_back(N->getMacinfoType());
1782   Record.push_back(N->getLine());
1783   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1784   Record.push_back(VE.getMetadataOrNullID(N->getRawValue()));
1785 
1786   Stream.EmitRecord(bitc::METADATA_MACRO, Record, Abbrev);
1787   Record.clear();
1788 }
1789 
1790 void ModuleBitcodeWriter::writeDIMacroFile(const DIMacroFile *N,
1791                                            SmallVectorImpl<uint64_t> &Record,
1792                                            unsigned Abbrev) {
1793   Record.push_back(N->isDistinct());
1794   Record.push_back(N->getMacinfoType());
1795   Record.push_back(N->getLine());
1796   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1797   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1798 
1799   Stream.EmitRecord(bitc::METADATA_MACRO_FILE, Record, Abbrev);
1800   Record.clear();
1801 }
1802 
1803 void ModuleBitcodeWriter::writeDIModule(const DIModule *N,
1804                                         SmallVectorImpl<uint64_t> &Record,
1805                                         unsigned Abbrev) {
1806   Record.push_back(N->isDistinct());
1807   for (auto &I : N->operands())
1808     Record.push_back(VE.getMetadataOrNullID(I));
1809 
1810   Stream.EmitRecord(bitc::METADATA_MODULE, Record, Abbrev);
1811   Record.clear();
1812 }
1813 
1814 void ModuleBitcodeWriter::writeDITemplateTypeParameter(
1815     const DITemplateTypeParameter *N, SmallVectorImpl<uint64_t> &Record,
1816     unsigned Abbrev) {
1817   Record.push_back(N->isDistinct());
1818   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1819   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1820   Record.push_back(N->isDefault());
1821 
1822   Stream.EmitRecord(bitc::METADATA_TEMPLATE_TYPE, Record, Abbrev);
1823   Record.clear();
1824 }
1825 
1826 void ModuleBitcodeWriter::writeDITemplateValueParameter(
1827     const DITemplateValueParameter *N, SmallVectorImpl<uint64_t> &Record,
1828     unsigned Abbrev) {
1829   Record.push_back(N->isDistinct());
1830   Record.push_back(N->getTag());
1831   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1832   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1833   Record.push_back(N->isDefault());
1834   Record.push_back(VE.getMetadataOrNullID(N->getValue()));
1835 
1836   Stream.EmitRecord(bitc::METADATA_TEMPLATE_VALUE, Record, Abbrev);
1837   Record.clear();
1838 }
1839 
1840 void ModuleBitcodeWriter::writeDIGlobalVariable(
1841     const DIGlobalVariable *N, SmallVectorImpl<uint64_t> &Record,
1842     unsigned Abbrev) {
1843   const uint64_t Version = 2 << 1;
1844   Record.push_back((uint64_t)N->isDistinct() | Version);
1845   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1846   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1847   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1848   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1849   Record.push_back(N->getLine());
1850   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1851   Record.push_back(N->isLocalToUnit());
1852   Record.push_back(N->isDefinition());
1853   Record.push_back(VE.getMetadataOrNullID(N->getStaticDataMemberDeclaration()));
1854   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams()));
1855   Record.push_back(N->getAlignInBits());
1856 
1857   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR, Record, Abbrev);
1858   Record.clear();
1859 }
1860 
1861 void ModuleBitcodeWriter::writeDILocalVariable(
1862     const DILocalVariable *N, SmallVectorImpl<uint64_t> &Record,
1863     unsigned Abbrev) {
1864   // In order to support all possible bitcode formats in BitcodeReader we need
1865   // to distinguish the following cases:
1866   // 1) Record has no artificial tag (Record[1]),
1867   //   has no obsolete inlinedAt field (Record[9]).
1868   //   In this case Record size will be 8, HasAlignment flag is false.
1869   // 2) Record has artificial tag (Record[1]),
1870   //   has no obsolete inlignedAt field (Record[9]).
1871   //   In this case Record size will be 9, HasAlignment flag is false.
1872   // 3) Record has both artificial tag (Record[1]) and
1873   //   obsolete inlignedAt field (Record[9]).
1874   //   In this case Record size will be 10, HasAlignment flag is false.
1875   // 4) Record has neither artificial tag, nor inlignedAt field, but
1876   //   HasAlignment flag is true and Record[8] contains alignment value.
1877   const uint64_t HasAlignmentFlag = 1 << 1;
1878   Record.push_back((uint64_t)N->isDistinct() | HasAlignmentFlag);
1879   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1880   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1881   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1882   Record.push_back(N->getLine());
1883   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1884   Record.push_back(N->getArg());
1885   Record.push_back(N->getFlags());
1886   Record.push_back(N->getAlignInBits());
1887 
1888   Stream.EmitRecord(bitc::METADATA_LOCAL_VAR, Record, Abbrev);
1889   Record.clear();
1890 }
1891 
1892 void ModuleBitcodeWriter::writeDILabel(
1893     const DILabel *N, SmallVectorImpl<uint64_t> &Record,
1894     unsigned Abbrev) {
1895   Record.push_back((uint64_t)N->isDistinct());
1896   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1897   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1898   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1899   Record.push_back(N->getLine());
1900 
1901   Stream.EmitRecord(bitc::METADATA_LABEL, Record, Abbrev);
1902   Record.clear();
1903 }
1904 
1905 void ModuleBitcodeWriter::writeDIExpression(const DIExpression *N,
1906                                             SmallVectorImpl<uint64_t> &Record,
1907                                             unsigned Abbrev) {
1908   Record.reserve(N->getElements().size() + 1);
1909   const uint64_t Version = 3 << 1;
1910   Record.push_back((uint64_t)N->isDistinct() | Version);
1911   Record.append(N->elements_begin(), N->elements_end());
1912 
1913   Stream.EmitRecord(bitc::METADATA_EXPRESSION, Record, Abbrev);
1914   Record.clear();
1915 }
1916 
1917 void ModuleBitcodeWriter::writeDIGlobalVariableExpression(
1918     const DIGlobalVariableExpression *N, SmallVectorImpl<uint64_t> &Record,
1919     unsigned Abbrev) {
1920   Record.push_back(N->isDistinct());
1921   Record.push_back(VE.getMetadataOrNullID(N->getVariable()));
1922   Record.push_back(VE.getMetadataOrNullID(N->getExpression()));
1923 
1924   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR_EXPR, Record, Abbrev);
1925   Record.clear();
1926 }
1927 
1928 void ModuleBitcodeWriter::writeDIObjCProperty(const DIObjCProperty *N,
1929                                               SmallVectorImpl<uint64_t> &Record,
1930                                               unsigned Abbrev) {
1931   Record.push_back(N->isDistinct());
1932   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1933   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1934   Record.push_back(N->getLine());
1935   Record.push_back(VE.getMetadataOrNullID(N->getRawSetterName()));
1936   Record.push_back(VE.getMetadataOrNullID(N->getRawGetterName()));
1937   Record.push_back(N->getAttributes());
1938   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1939 
1940   Stream.EmitRecord(bitc::METADATA_OBJC_PROPERTY, Record, Abbrev);
1941   Record.clear();
1942 }
1943 
1944 void ModuleBitcodeWriter::writeDIImportedEntity(
1945     const DIImportedEntity *N, SmallVectorImpl<uint64_t> &Record,
1946     unsigned Abbrev) {
1947   Record.push_back(N->isDistinct());
1948   Record.push_back(N->getTag());
1949   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1950   Record.push_back(VE.getMetadataOrNullID(N->getEntity()));
1951   Record.push_back(N->getLine());
1952   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1953   Record.push_back(VE.getMetadataOrNullID(N->getRawFile()));
1954 
1955   Stream.EmitRecord(bitc::METADATA_IMPORTED_ENTITY, Record, Abbrev);
1956   Record.clear();
1957 }
1958 
1959 unsigned ModuleBitcodeWriter::createNamedMetadataAbbrev() {
1960   auto Abbv = std::make_shared<BitCodeAbbrev>();
1961   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
1962   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1963   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1964   return Stream.EmitAbbrev(std::move(Abbv));
1965 }
1966 
1967 void ModuleBitcodeWriter::writeNamedMetadata(
1968     SmallVectorImpl<uint64_t> &Record) {
1969   if (M.named_metadata_empty())
1970     return;
1971 
1972   unsigned Abbrev = createNamedMetadataAbbrev();
1973   for (const NamedMDNode &NMD : M.named_metadata()) {
1974     // Write name.
1975     StringRef Str = NMD.getName();
1976     Record.append(Str.bytes_begin(), Str.bytes_end());
1977     Stream.EmitRecord(bitc::METADATA_NAME, Record, Abbrev);
1978     Record.clear();
1979 
1980     // Write named metadata operands.
1981     for (const MDNode *N : NMD.operands())
1982       Record.push_back(VE.getMetadataID(N));
1983     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
1984     Record.clear();
1985   }
1986 }
1987 
1988 unsigned ModuleBitcodeWriter::createMetadataStringsAbbrev() {
1989   auto Abbv = std::make_shared<BitCodeAbbrev>();
1990   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRINGS));
1991   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // # of strings
1992   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // offset to chars
1993   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
1994   return Stream.EmitAbbrev(std::move(Abbv));
1995 }
1996 
1997 /// Write out a record for MDString.
1998 ///
1999 /// All the metadata strings in a metadata block are emitted in a single
2000 /// record.  The sizes and strings themselves are shoved into a blob.
2001 void ModuleBitcodeWriter::writeMetadataStrings(
2002     ArrayRef<const Metadata *> Strings, SmallVectorImpl<uint64_t> &Record) {
2003   if (Strings.empty())
2004     return;
2005 
2006   // Start the record with the number of strings.
2007   Record.push_back(bitc::METADATA_STRINGS);
2008   Record.push_back(Strings.size());
2009 
2010   // Emit the sizes of the strings in the blob.
2011   SmallString<256> Blob;
2012   {
2013     BitstreamWriter W(Blob);
2014     for (const Metadata *MD : Strings)
2015       W.EmitVBR(cast<MDString>(MD)->getLength(), 6);
2016     W.FlushToWord();
2017   }
2018 
2019   // Add the offset to the strings to the record.
2020   Record.push_back(Blob.size());
2021 
2022   // Add the strings to the blob.
2023   for (const Metadata *MD : Strings)
2024     Blob.append(cast<MDString>(MD)->getString());
2025 
2026   // Emit the final record.
2027   Stream.EmitRecordWithBlob(createMetadataStringsAbbrev(), Record, Blob);
2028   Record.clear();
2029 }
2030 
2031 // Generates an enum to use as an index in the Abbrev array of Metadata record.
2032 enum MetadataAbbrev : unsigned {
2033 #define HANDLE_MDNODE_LEAF(CLASS) CLASS##AbbrevID,
2034 #include "llvm/IR/Metadata.def"
2035   LastPlusOne
2036 };
2037 
2038 void ModuleBitcodeWriter::writeMetadataRecords(
2039     ArrayRef<const Metadata *> MDs, SmallVectorImpl<uint64_t> &Record,
2040     std::vector<unsigned> *MDAbbrevs, std::vector<uint64_t> *IndexPos) {
2041   if (MDs.empty())
2042     return;
2043 
2044   // Initialize MDNode abbreviations.
2045 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
2046 #include "llvm/IR/Metadata.def"
2047 
2048   for (const Metadata *MD : MDs) {
2049     if (IndexPos)
2050       IndexPos->push_back(Stream.GetCurrentBitNo());
2051     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
2052       assert(N->isResolved() && "Expected forward references to be resolved");
2053 
2054       switch (N->getMetadataID()) {
2055       default:
2056         llvm_unreachable("Invalid MDNode subclass");
2057 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
2058   case Metadata::CLASS##Kind:                                                  \
2059     if (MDAbbrevs)                                                             \
2060       write##CLASS(cast<CLASS>(N), Record,                                     \
2061                    (*MDAbbrevs)[MetadataAbbrev::CLASS##AbbrevID]);             \
2062     else                                                                       \
2063       write##CLASS(cast<CLASS>(N), Record, CLASS##Abbrev);                     \
2064     continue;
2065 #include "llvm/IR/Metadata.def"
2066       }
2067     }
2068     writeValueAsMetadata(cast<ValueAsMetadata>(MD), Record);
2069   }
2070 }
2071 
2072 void ModuleBitcodeWriter::writeModuleMetadata() {
2073   if (!VE.hasMDs() && M.named_metadata_empty())
2074     return;
2075 
2076   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 4);
2077   SmallVector<uint64_t, 64> Record;
2078 
2079   // Emit all abbrevs upfront, so that the reader can jump in the middle of the
2080   // block and load any metadata.
2081   std::vector<unsigned> MDAbbrevs;
2082 
2083   MDAbbrevs.resize(MetadataAbbrev::LastPlusOne);
2084   MDAbbrevs[MetadataAbbrev::DILocationAbbrevID] = createDILocationAbbrev();
2085   MDAbbrevs[MetadataAbbrev::GenericDINodeAbbrevID] =
2086       createGenericDINodeAbbrev();
2087 
2088   auto Abbv = std::make_shared<BitCodeAbbrev>();
2089   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX_OFFSET));
2090   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2091   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2092   unsigned OffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2093 
2094   Abbv = std::make_shared<BitCodeAbbrev>();
2095   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX));
2096   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2097   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2098   unsigned IndexAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2099 
2100   // Emit MDStrings together upfront.
2101   writeMetadataStrings(VE.getMDStrings(), Record);
2102 
2103   // We only emit an index for the metadata record if we have more than a given
2104   // (naive) threshold of metadatas, otherwise it is not worth it.
2105   if (VE.getNonMDStrings().size() > IndexThreshold) {
2106     // Write a placeholder value in for the offset of the metadata index,
2107     // which is written after the records, so that it can include
2108     // the offset of each entry. The placeholder offset will be
2109     // updated after all records are emitted.
2110     uint64_t Vals[] = {0, 0};
2111     Stream.EmitRecord(bitc::METADATA_INDEX_OFFSET, Vals, OffsetAbbrev);
2112   }
2113 
2114   // Compute and save the bit offset to the current position, which will be
2115   // patched when we emit the index later. We can simply subtract the 64-bit
2116   // fixed size from the current bit number to get the location to backpatch.
2117   uint64_t IndexOffsetRecordBitPos = Stream.GetCurrentBitNo();
2118 
2119   // This index will contain the bitpos for each individual record.
2120   std::vector<uint64_t> IndexPos;
2121   IndexPos.reserve(VE.getNonMDStrings().size());
2122 
2123   // Write all the records
2124   writeMetadataRecords(VE.getNonMDStrings(), Record, &MDAbbrevs, &IndexPos);
2125 
2126   if (VE.getNonMDStrings().size() > IndexThreshold) {
2127     // Now that we have emitted all the records we will emit the index. But
2128     // first
2129     // backpatch the forward reference so that the reader can skip the records
2130     // efficiently.
2131     Stream.BackpatchWord64(IndexOffsetRecordBitPos - 64,
2132                            Stream.GetCurrentBitNo() - IndexOffsetRecordBitPos);
2133 
2134     // Delta encode the index.
2135     uint64_t PreviousValue = IndexOffsetRecordBitPos;
2136     for (auto &Elt : IndexPos) {
2137       auto EltDelta = Elt - PreviousValue;
2138       PreviousValue = Elt;
2139       Elt = EltDelta;
2140     }
2141     // Emit the index record.
2142     Stream.EmitRecord(bitc::METADATA_INDEX, IndexPos, IndexAbbrev);
2143     IndexPos.clear();
2144   }
2145 
2146   // Write the named metadata now.
2147   writeNamedMetadata(Record);
2148 
2149   auto AddDeclAttachedMetadata = [&](const GlobalObject &GO) {
2150     SmallVector<uint64_t, 4> Record;
2151     Record.push_back(VE.getValueID(&GO));
2152     pushGlobalMetadataAttachment(Record, GO);
2153     Stream.EmitRecord(bitc::METADATA_GLOBAL_DECL_ATTACHMENT, Record);
2154   };
2155   for (const Function &F : M)
2156     if (F.isDeclaration() && F.hasMetadata())
2157       AddDeclAttachedMetadata(F);
2158   // FIXME: Only store metadata for declarations here, and move data for global
2159   // variable definitions to a separate block (PR28134).
2160   for (const GlobalVariable &GV : M.globals())
2161     if (GV.hasMetadata())
2162       AddDeclAttachedMetadata(GV);
2163 
2164   Stream.ExitBlock();
2165 }
2166 
2167 void ModuleBitcodeWriter::writeFunctionMetadata(const Function &F) {
2168   if (!VE.hasMDs())
2169     return;
2170 
2171   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
2172   SmallVector<uint64_t, 64> Record;
2173   writeMetadataStrings(VE.getMDStrings(), Record);
2174   writeMetadataRecords(VE.getNonMDStrings(), Record);
2175   Stream.ExitBlock();
2176 }
2177 
2178 void ModuleBitcodeWriter::pushGlobalMetadataAttachment(
2179     SmallVectorImpl<uint64_t> &Record, const GlobalObject &GO) {
2180   // [n x [id, mdnode]]
2181   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2182   GO.getAllMetadata(MDs);
2183   for (const auto &I : MDs) {
2184     Record.push_back(I.first);
2185     Record.push_back(VE.getMetadataID(I.second));
2186   }
2187 }
2188 
2189 void ModuleBitcodeWriter::writeFunctionMetadataAttachment(const Function &F) {
2190   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
2191 
2192   SmallVector<uint64_t, 64> Record;
2193 
2194   if (F.hasMetadata()) {
2195     pushGlobalMetadataAttachment(Record, F);
2196     Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2197     Record.clear();
2198   }
2199 
2200   // Write metadata attachments
2201   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
2202   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2203   for (const BasicBlock &BB : F)
2204     for (const Instruction &I : BB) {
2205       MDs.clear();
2206       I.getAllMetadataOtherThanDebugLoc(MDs);
2207 
2208       // If no metadata, ignore instruction.
2209       if (MDs.empty()) continue;
2210 
2211       Record.push_back(VE.getInstructionID(&I));
2212 
2213       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
2214         Record.push_back(MDs[i].first);
2215         Record.push_back(VE.getMetadataID(MDs[i].second));
2216       }
2217       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2218       Record.clear();
2219     }
2220 
2221   Stream.ExitBlock();
2222 }
2223 
2224 void ModuleBitcodeWriter::writeModuleMetadataKinds() {
2225   SmallVector<uint64_t, 64> Record;
2226 
2227   // Write metadata kinds
2228   // METADATA_KIND - [n x [id, name]]
2229   SmallVector<StringRef, 8> Names;
2230   M.getMDKindNames(Names);
2231 
2232   if (Names.empty()) return;
2233 
2234   Stream.EnterSubblock(bitc::METADATA_KIND_BLOCK_ID, 3);
2235 
2236   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
2237     Record.push_back(MDKindID);
2238     StringRef KName = Names[MDKindID];
2239     Record.append(KName.begin(), KName.end());
2240 
2241     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
2242     Record.clear();
2243   }
2244 
2245   Stream.ExitBlock();
2246 }
2247 
2248 void ModuleBitcodeWriter::writeOperandBundleTags() {
2249   // Write metadata kinds
2250   //
2251   // OPERAND_BUNDLE_TAGS_BLOCK_ID : N x OPERAND_BUNDLE_TAG
2252   //
2253   // OPERAND_BUNDLE_TAG - [strchr x N]
2254 
2255   SmallVector<StringRef, 8> Tags;
2256   M.getOperandBundleTags(Tags);
2257 
2258   if (Tags.empty())
2259     return;
2260 
2261   Stream.EnterSubblock(bitc::OPERAND_BUNDLE_TAGS_BLOCK_ID, 3);
2262 
2263   SmallVector<uint64_t, 64> Record;
2264 
2265   for (auto Tag : Tags) {
2266     Record.append(Tag.begin(), Tag.end());
2267 
2268     Stream.EmitRecord(bitc::OPERAND_BUNDLE_TAG, Record, 0);
2269     Record.clear();
2270   }
2271 
2272   Stream.ExitBlock();
2273 }
2274 
2275 void ModuleBitcodeWriter::writeSyncScopeNames() {
2276   SmallVector<StringRef, 8> SSNs;
2277   M.getContext().getSyncScopeNames(SSNs);
2278   if (SSNs.empty())
2279     return;
2280 
2281   Stream.EnterSubblock(bitc::SYNC_SCOPE_NAMES_BLOCK_ID, 2);
2282 
2283   SmallVector<uint64_t, 64> Record;
2284   for (auto SSN : SSNs) {
2285     Record.append(SSN.begin(), SSN.end());
2286     Stream.EmitRecord(bitc::SYNC_SCOPE_NAME, Record, 0);
2287     Record.clear();
2288   }
2289 
2290   Stream.ExitBlock();
2291 }
2292 
2293 void ModuleBitcodeWriter::writeConstants(unsigned FirstVal, unsigned LastVal,
2294                                          bool isGlobal) {
2295   if (FirstVal == LastVal) return;
2296 
2297   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
2298 
2299   unsigned AggregateAbbrev = 0;
2300   unsigned String8Abbrev = 0;
2301   unsigned CString7Abbrev = 0;
2302   unsigned CString6Abbrev = 0;
2303   // If this is a constant pool for the module, emit module-specific abbrevs.
2304   if (isGlobal) {
2305     // Abbrev for CST_CODE_AGGREGATE.
2306     auto Abbv = std::make_shared<BitCodeAbbrev>();
2307     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
2308     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2309     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
2310     AggregateAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2311 
2312     // Abbrev for CST_CODE_STRING.
2313     Abbv = std::make_shared<BitCodeAbbrev>();
2314     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
2315     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2316     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2317     String8Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2318     // Abbrev for CST_CODE_CSTRING.
2319     Abbv = std::make_shared<BitCodeAbbrev>();
2320     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2321     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2322     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2323     CString7Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2324     // Abbrev for CST_CODE_CSTRING.
2325     Abbv = std::make_shared<BitCodeAbbrev>();
2326     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2327     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2328     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2329     CString6Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2330   }
2331 
2332   SmallVector<uint64_t, 64> Record;
2333 
2334   const ValueEnumerator::ValueList &Vals = VE.getValues();
2335   Type *LastTy = nullptr;
2336   for (unsigned i = FirstVal; i != LastVal; ++i) {
2337     const Value *V = Vals[i].first;
2338     // If we need to switch types, do so now.
2339     if (V->getType() != LastTy) {
2340       LastTy = V->getType();
2341       Record.push_back(VE.getTypeID(LastTy));
2342       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
2343                         CONSTANTS_SETTYPE_ABBREV);
2344       Record.clear();
2345     }
2346 
2347     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
2348       Record.push_back(unsigned(IA->hasSideEffects()) |
2349                        unsigned(IA->isAlignStack()) << 1 |
2350                        unsigned(IA->getDialect()&1) << 2);
2351 
2352       // Add the asm string.
2353       const std::string &AsmStr = IA->getAsmString();
2354       Record.push_back(AsmStr.size());
2355       Record.append(AsmStr.begin(), AsmStr.end());
2356 
2357       // Add the constraint string.
2358       const std::string &ConstraintStr = IA->getConstraintString();
2359       Record.push_back(ConstraintStr.size());
2360       Record.append(ConstraintStr.begin(), ConstraintStr.end());
2361       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
2362       Record.clear();
2363       continue;
2364     }
2365     const Constant *C = cast<Constant>(V);
2366     unsigned Code = -1U;
2367     unsigned AbbrevToUse = 0;
2368     if (C->isNullValue()) {
2369       Code = bitc::CST_CODE_NULL;
2370     } else if (isa<UndefValue>(C)) {
2371       Code = bitc::CST_CODE_UNDEF;
2372     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
2373       if (IV->getBitWidth() <= 64) {
2374         uint64_t V = IV->getSExtValue();
2375         emitSignedInt64(Record, V);
2376         Code = bitc::CST_CODE_INTEGER;
2377         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
2378       } else {                             // Wide integers, > 64 bits in size.
2379         emitWideAPInt(Record, IV->getValue());
2380         Code = bitc::CST_CODE_WIDE_INTEGER;
2381       }
2382     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
2383       Code = bitc::CST_CODE_FLOAT;
2384       Type *Ty = CFP->getType();
2385       if (Ty->isHalfTy() || Ty->isFloatTy() || Ty->isDoubleTy()) {
2386         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
2387       } else if (Ty->isX86_FP80Ty()) {
2388         // api needed to prevent premature destruction
2389         // bits are not in the same order as a normal i80 APInt, compensate.
2390         APInt api = CFP->getValueAPF().bitcastToAPInt();
2391         const uint64_t *p = api.getRawData();
2392         Record.push_back((p[1] << 48) | (p[0] >> 16));
2393         Record.push_back(p[0] & 0xffffLL);
2394       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
2395         APInt api = CFP->getValueAPF().bitcastToAPInt();
2396         const uint64_t *p = api.getRawData();
2397         Record.push_back(p[0]);
2398         Record.push_back(p[1]);
2399       } else {
2400         assert(0 && "Unknown FP type!");
2401       }
2402     } else if (isa<ConstantDataSequential>(C) &&
2403                cast<ConstantDataSequential>(C)->isString()) {
2404       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
2405       // Emit constant strings specially.
2406       unsigned NumElts = Str->getNumElements();
2407       // If this is a null-terminated string, use the denser CSTRING encoding.
2408       if (Str->isCString()) {
2409         Code = bitc::CST_CODE_CSTRING;
2410         --NumElts;  // Don't encode the null, which isn't allowed by char6.
2411       } else {
2412         Code = bitc::CST_CODE_STRING;
2413         AbbrevToUse = String8Abbrev;
2414       }
2415       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
2416       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
2417       for (unsigned i = 0; i != NumElts; ++i) {
2418         unsigned char V = Str->getElementAsInteger(i);
2419         Record.push_back(V);
2420         isCStr7 &= (V & 128) == 0;
2421         if (isCStrChar6)
2422           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
2423       }
2424 
2425       if (isCStrChar6)
2426         AbbrevToUse = CString6Abbrev;
2427       else if (isCStr7)
2428         AbbrevToUse = CString7Abbrev;
2429     } else if (const ConstantDataSequential *CDS =
2430                   dyn_cast<ConstantDataSequential>(C)) {
2431       Code = bitc::CST_CODE_DATA;
2432       Type *EltTy = CDS->getElementType();
2433       if (isa<IntegerType>(EltTy)) {
2434         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2435           Record.push_back(CDS->getElementAsInteger(i));
2436       } else {
2437         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2438           Record.push_back(
2439               CDS->getElementAsAPFloat(i).bitcastToAPInt().getLimitedValue());
2440       }
2441     } else if (isa<ConstantAggregate>(C)) {
2442       Code = bitc::CST_CODE_AGGREGATE;
2443       for (const Value *Op : C->operands())
2444         Record.push_back(VE.getValueID(Op));
2445       AbbrevToUse = AggregateAbbrev;
2446     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
2447       switch (CE->getOpcode()) {
2448       default:
2449         if (Instruction::isCast(CE->getOpcode())) {
2450           Code = bitc::CST_CODE_CE_CAST;
2451           Record.push_back(getEncodedCastOpcode(CE->getOpcode()));
2452           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2453           Record.push_back(VE.getValueID(C->getOperand(0)));
2454           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
2455         } else {
2456           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
2457           Code = bitc::CST_CODE_CE_BINOP;
2458           Record.push_back(getEncodedBinaryOpcode(CE->getOpcode()));
2459           Record.push_back(VE.getValueID(C->getOperand(0)));
2460           Record.push_back(VE.getValueID(C->getOperand(1)));
2461           uint64_t Flags = getOptimizationFlags(CE);
2462           if (Flags != 0)
2463             Record.push_back(Flags);
2464         }
2465         break;
2466       case Instruction::FNeg: {
2467         assert(CE->getNumOperands() == 1 && "Unknown constant expr!");
2468         Code = bitc::CST_CODE_CE_UNOP;
2469         Record.push_back(getEncodedUnaryOpcode(CE->getOpcode()));
2470         Record.push_back(VE.getValueID(C->getOperand(0)));
2471         uint64_t Flags = getOptimizationFlags(CE);
2472         if (Flags != 0)
2473           Record.push_back(Flags);
2474         break;
2475       }
2476       case Instruction::GetElementPtr: {
2477         Code = bitc::CST_CODE_CE_GEP;
2478         const auto *GO = cast<GEPOperator>(C);
2479         Record.push_back(VE.getTypeID(GO->getSourceElementType()));
2480         if (Optional<unsigned> Idx = GO->getInRangeIndex()) {
2481           Code = bitc::CST_CODE_CE_GEP_WITH_INRANGE_INDEX;
2482           Record.push_back((*Idx << 1) | GO->isInBounds());
2483         } else if (GO->isInBounds())
2484           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
2485         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
2486           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
2487           Record.push_back(VE.getValueID(C->getOperand(i)));
2488         }
2489         break;
2490       }
2491       case Instruction::Select:
2492         Code = bitc::CST_CODE_CE_SELECT;
2493         Record.push_back(VE.getValueID(C->getOperand(0)));
2494         Record.push_back(VE.getValueID(C->getOperand(1)));
2495         Record.push_back(VE.getValueID(C->getOperand(2)));
2496         break;
2497       case Instruction::ExtractElement:
2498         Code = bitc::CST_CODE_CE_EXTRACTELT;
2499         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2500         Record.push_back(VE.getValueID(C->getOperand(0)));
2501         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
2502         Record.push_back(VE.getValueID(C->getOperand(1)));
2503         break;
2504       case Instruction::InsertElement:
2505         Code = bitc::CST_CODE_CE_INSERTELT;
2506         Record.push_back(VE.getValueID(C->getOperand(0)));
2507         Record.push_back(VE.getValueID(C->getOperand(1)));
2508         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
2509         Record.push_back(VE.getValueID(C->getOperand(2)));
2510         break;
2511       case Instruction::ShuffleVector:
2512         // If the return type and argument types are the same, this is a
2513         // standard shufflevector instruction.  If the types are different,
2514         // then the shuffle is widening or truncating the input vectors, and
2515         // the argument type must also be encoded.
2516         if (C->getType() == C->getOperand(0)->getType()) {
2517           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
2518         } else {
2519           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
2520           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2521         }
2522         Record.push_back(VE.getValueID(C->getOperand(0)));
2523         Record.push_back(VE.getValueID(C->getOperand(1)));
2524         Record.push_back(VE.getValueID(CE->getShuffleMaskForBitcode()));
2525         break;
2526       case Instruction::ICmp:
2527       case Instruction::FCmp:
2528         Code = bitc::CST_CODE_CE_CMP;
2529         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2530         Record.push_back(VE.getValueID(C->getOperand(0)));
2531         Record.push_back(VE.getValueID(C->getOperand(1)));
2532         Record.push_back(CE->getPredicate());
2533         break;
2534       }
2535     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
2536       Code = bitc::CST_CODE_BLOCKADDRESS;
2537       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
2538       Record.push_back(VE.getValueID(BA->getFunction()));
2539       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
2540     } else {
2541 #ifndef NDEBUG
2542       C->dump();
2543 #endif
2544       llvm_unreachable("Unknown constant!");
2545     }
2546     Stream.EmitRecord(Code, Record, AbbrevToUse);
2547     Record.clear();
2548   }
2549 
2550   Stream.ExitBlock();
2551 }
2552 
2553 void ModuleBitcodeWriter::writeModuleConstants() {
2554   const ValueEnumerator::ValueList &Vals = VE.getValues();
2555 
2556   // Find the first constant to emit, which is the first non-globalvalue value.
2557   // We know globalvalues have been emitted by WriteModuleInfo.
2558   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
2559     if (!isa<GlobalValue>(Vals[i].first)) {
2560       writeConstants(i, Vals.size(), true);
2561       return;
2562     }
2563   }
2564 }
2565 
2566 /// pushValueAndType - The file has to encode both the value and type id for
2567 /// many values, because we need to know what type to create for forward
2568 /// references.  However, most operands are not forward references, so this type
2569 /// field is not needed.
2570 ///
2571 /// This function adds V's value ID to Vals.  If the value ID is higher than the
2572 /// instruction ID, then it is a forward reference, and it also includes the
2573 /// type ID.  The value ID that is written is encoded relative to the InstID.
2574 bool ModuleBitcodeWriter::pushValueAndType(const Value *V, unsigned InstID,
2575                                            SmallVectorImpl<unsigned> &Vals) {
2576   unsigned ValID = VE.getValueID(V);
2577   // Make encoding relative to the InstID.
2578   Vals.push_back(InstID - ValID);
2579   if (ValID >= InstID) {
2580     Vals.push_back(VE.getTypeID(V->getType()));
2581     return true;
2582   }
2583   return false;
2584 }
2585 
2586 void ModuleBitcodeWriter::writeOperandBundles(ImmutableCallSite CS,
2587                                               unsigned InstID) {
2588   SmallVector<unsigned, 64> Record;
2589   LLVMContext &C = CS.getInstruction()->getContext();
2590 
2591   for (unsigned i = 0, e = CS.getNumOperandBundles(); i != e; ++i) {
2592     const auto &Bundle = CS.getOperandBundleAt(i);
2593     Record.push_back(C.getOperandBundleTagID(Bundle.getTagName()));
2594 
2595     for (auto &Input : Bundle.Inputs)
2596       pushValueAndType(Input, InstID, Record);
2597 
2598     Stream.EmitRecord(bitc::FUNC_CODE_OPERAND_BUNDLE, Record);
2599     Record.clear();
2600   }
2601 }
2602 
2603 /// pushValue - Like pushValueAndType, but where the type of the value is
2604 /// omitted (perhaps it was already encoded in an earlier operand).
2605 void ModuleBitcodeWriter::pushValue(const Value *V, unsigned InstID,
2606                                     SmallVectorImpl<unsigned> &Vals) {
2607   unsigned ValID = VE.getValueID(V);
2608   Vals.push_back(InstID - ValID);
2609 }
2610 
2611 void ModuleBitcodeWriter::pushValueSigned(const Value *V, unsigned InstID,
2612                                           SmallVectorImpl<uint64_t> &Vals) {
2613   unsigned ValID = VE.getValueID(V);
2614   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
2615   emitSignedInt64(Vals, diff);
2616 }
2617 
2618 /// WriteInstruction - Emit an instruction to the specified stream.
2619 void ModuleBitcodeWriter::writeInstruction(const Instruction &I,
2620                                            unsigned InstID,
2621                                            SmallVectorImpl<unsigned> &Vals) {
2622   unsigned Code = 0;
2623   unsigned AbbrevToUse = 0;
2624   VE.setInstructionID(&I);
2625   switch (I.getOpcode()) {
2626   default:
2627     if (Instruction::isCast(I.getOpcode())) {
2628       Code = bitc::FUNC_CODE_INST_CAST;
2629       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2630         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
2631       Vals.push_back(VE.getTypeID(I.getType()));
2632       Vals.push_back(getEncodedCastOpcode(I.getOpcode()));
2633     } else {
2634       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
2635       Code = bitc::FUNC_CODE_INST_BINOP;
2636       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2637         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
2638       pushValue(I.getOperand(1), InstID, Vals);
2639       Vals.push_back(getEncodedBinaryOpcode(I.getOpcode()));
2640       uint64_t Flags = getOptimizationFlags(&I);
2641       if (Flags != 0) {
2642         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
2643           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
2644         Vals.push_back(Flags);
2645       }
2646     }
2647     break;
2648   case Instruction::FNeg: {
2649     Code = bitc::FUNC_CODE_INST_UNOP;
2650     if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2651       AbbrevToUse = FUNCTION_INST_UNOP_ABBREV;
2652     Vals.push_back(getEncodedUnaryOpcode(I.getOpcode()));
2653     uint64_t Flags = getOptimizationFlags(&I);
2654     if (Flags != 0) {
2655       if (AbbrevToUse == FUNCTION_INST_UNOP_ABBREV)
2656         AbbrevToUse = FUNCTION_INST_UNOP_FLAGS_ABBREV;
2657       Vals.push_back(Flags);
2658     }
2659     break;
2660   }
2661   case Instruction::GetElementPtr: {
2662     Code = bitc::FUNC_CODE_INST_GEP;
2663     AbbrevToUse = FUNCTION_INST_GEP_ABBREV;
2664     auto &GEPInst = cast<GetElementPtrInst>(I);
2665     Vals.push_back(GEPInst.isInBounds());
2666     Vals.push_back(VE.getTypeID(GEPInst.getSourceElementType()));
2667     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
2668       pushValueAndType(I.getOperand(i), InstID, Vals);
2669     break;
2670   }
2671   case Instruction::ExtractValue: {
2672     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
2673     pushValueAndType(I.getOperand(0), InstID, Vals);
2674     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
2675     Vals.append(EVI->idx_begin(), EVI->idx_end());
2676     break;
2677   }
2678   case Instruction::InsertValue: {
2679     Code = bitc::FUNC_CODE_INST_INSERTVAL;
2680     pushValueAndType(I.getOperand(0), InstID, Vals);
2681     pushValueAndType(I.getOperand(1), InstID, Vals);
2682     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
2683     Vals.append(IVI->idx_begin(), IVI->idx_end());
2684     break;
2685   }
2686   case Instruction::Select: {
2687     Code = bitc::FUNC_CODE_INST_VSELECT;
2688     pushValueAndType(I.getOperand(1), InstID, Vals);
2689     pushValue(I.getOperand(2), InstID, Vals);
2690     pushValueAndType(I.getOperand(0), InstID, Vals);
2691     uint64_t Flags = getOptimizationFlags(&I);
2692     if (Flags != 0)
2693       Vals.push_back(Flags);
2694     break;
2695   }
2696   case Instruction::ExtractElement:
2697     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
2698     pushValueAndType(I.getOperand(0), InstID, Vals);
2699     pushValueAndType(I.getOperand(1), InstID, Vals);
2700     break;
2701   case Instruction::InsertElement:
2702     Code = bitc::FUNC_CODE_INST_INSERTELT;
2703     pushValueAndType(I.getOperand(0), InstID, Vals);
2704     pushValue(I.getOperand(1), InstID, Vals);
2705     pushValueAndType(I.getOperand(2), InstID, Vals);
2706     break;
2707   case Instruction::ShuffleVector:
2708     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
2709     pushValueAndType(I.getOperand(0), InstID, Vals);
2710     pushValue(I.getOperand(1), InstID, Vals);
2711     pushValue(cast<ShuffleVectorInst>(I).getShuffleMaskForBitcode(), InstID,
2712               Vals);
2713     break;
2714   case Instruction::ICmp:
2715   case Instruction::FCmp: {
2716     // compare returning Int1Ty or vector of Int1Ty
2717     Code = bitc::FUNC_CODE_INST_CMP2;
2718     pushValueAndType(I.getOperand(0), InstID, Vals);
2719     pushValue(I.getOperand(1), InstID, Vals);
2720     Vals.push_back(cast<CmpInst>(I).getPredicate());
2721     uint64_t Flags = getOptimizationFlags(&I);
2722     if (Flags != 0)
2723       Vals.push_back(Flags);
2724     break;
2725   }
2726 
2727   case Instruction::Ret:
2728     {
2729       Code = bitc::FUNC_CODE_INST_RET;
2730       unsigned NumOperands = I.getNumOperands();
2731       if (NumOperands == 0)
2732         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
2733       else if (NumOperands == 1) {
2734         if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2735           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
2736       } else {
2737         for (unsigned i = 0, e = NumOperands; i != e; ++i)
2738           pushValueAndType(I.getOperand(i), InstID, Vals);
2739       }
2740     }
2741     break;
2742   case Instruction::Br:
2743     {
2744       Code = bitc::FUNC_CODE_INST_BR;
2745       const BranchInst &II = cast<BranchInst>(I);
2746       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
2747       if (II.isConditional()) {
2748         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
2749         pushValue(II.getCondition(), InstID, Vals);
2750       }
2751     }
2752     break;
2753   case Instruction::Switch:
2754     {
2755       Code = bitc::FUNC_CODE_INST_SWITCH;
2756       const SwitchInst &SI = cast<SwitchInst>(I);
2757       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
2758       pushValue(SI.getCondition(), InstID, Vals);
2759       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
2760       for (auto Case : SI.cases()) {
2761         Vals.push_back(VE.getValueID(Case.getCaseValue()));
2762         Vals.push_back(VE.getValueID(Case.getCaseSuccessor()));
2763       }
2764     }
2765     break;
2766   case Instruction::IndirectBr:
2767     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
2768     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2769     // Encode the address operand as relative, but not the basic blocks.
2770     pushValue(I.getOperand(0), InstID, Vals);
2771     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
2772       Vals.push_back(VE.getValueID(I.getOperand(i)));
2773     break;
2774 
2775   case Instruction::Invoke: {
2776     const InvokeInst *II = cast<InvokeInst>(&I);
2777     const Value *Callee = II->getCalledValue();
2778     FunctionType *FTy = II->getFunctionType();
2779 
2780     if (II->hasOperandBundles())
2781       writeOperandBundles(II, InstID);
2782 
2783     Code = bitc::FUNC_CODE_INST_INVOKE;
2784 
2785     Vals.push_back(VE.getAttributeListID(II->getAttributes()));
2786     Vals.push_back(II->getCallingConv() | 1 << 13);
2787     Vals.push_back(VE.getValueID(II->getNormalDest()));
2788     Vals.push_back(VE.getValueID(II->getUnwindDest()));
2789     Vals.push_back(VE.getTypeID(FTy));
2790     pushValueAndType(Callee, InstID, Vals);
2791 
2792     // Emit value #'s for the fixed parameters.
2793     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
2794       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
2795 
2796     // Emit type/value pairs for varargs params.
2797     if (FTy->isVarArg()) {
2798       for (unsigned i = FTy->getNumParams(), e = II->getNumArgOperands();
2799            i != e; ++i)
2800         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
2801     }
2802     break;
2803   }
2804   case Instruction::Resume:
2805     Code = bitc::FUNC_CODE_INST_RESUME;
2806     pushValueAndType(I.getOperand(0), InstID, Vals);
2807     break;
2808   case Instruction::CleanupRet: {
2809     Code = bitc::FUNC_CODE_INST_CLEANUPRET;
2810     const auto &CRI = cast<CleanupReturnInst>(I);
2811     pushValue(CRI.getCleanupPad(), InstID, Vals);
2812     if (CRI.hasUnwindDest())
2813       Vals.push_back(VE.getValueID(CRI.getUnwindDest()));
2814     break;
2815   }
2816   case Instruction::CatchRet: {
2817     Code = bitc::FUNC_CODE_INST_CATCHRET;
2818     const auto &CRI = cast<CatchReturnInst>(I);
2819     pushValue(CRI.getCatchPad(), InstID, Vals);
2820     Vals.push_back(VE.getValueID(CRI.getSuccessor()));
2821     break;
2822   }
2823   case Instruction::CleanupPad:
2824   case Instruction::CatchPad: {
2825     const auto &FuncletPad = cast<FuncletPadInst>(I);
2826     Code = isa<CatchPadInst>(FuncletPad) ? bitc::FUNC_CODE_INST_CATCHPAD
2827                                          : bitc::FUNC_CODE_INST_CLEANUPPAD;
2828     pushValue(FuncletPad.getParentPad(), InstID, Vals);
2829 
2830     unsigned NumArgOperands = FuncletPad.getNumArgOperands();
2831     Vals.push_back(NumArgOperands);
2832     for (unsigned Op = 0; Op != NumArgOperands; ++Op)
2833       pushValueAndType(FuncletPad.getArgOperand(Op), InstID, Vals);
2834     break;
2835   }
2836   case Instruction::CatchSwitch: {
2837     Code = bitc::FUNC_CODE_INST_CATCHSWITCH;
2838     const auto &CatchSwitch = cast<CatchSwitchInst>(I);
2839 
2840     pushValue(CatchSwitch.getParentPad(), InstID, Vals);
2841 
2842     unsigned NumHandlers = CatchSwitch.getNumHandlers();
2843     Vals.push_back(NumHandlers);
2844     for (const BasicBlock *CatchPadBB : CatchSwitch.handlers())
2845       Vals.push_back(VE.getValueID(CatchPadBB));
2846 
2847     if (CatchSwitch.hasUnwindDest())
2848       Vals.push_back(VE.getValueID(CatchSwitch.getUnwindDest()));
2849     break;
2850   }
2851   case Instruction::CallBr: {
2852     const CallBrInst *CBI = cast<CallBrInst>(&I);
2853     const Value *Callee = CBI->getCalledValue();
2854     FunctionType *FTy = CBI->getFunctionType();
2855 
2856     if (CBI->hasOperandBundles())
2857       writeOperandBundles(CBI, InstID);
2858 
2859     Code = bitc::FUNC_CODE_INST_CALLBR;
2860 
2861     Vals.push_back(VE.getAttributeListID(CBI->getAttributes()));
2862 
2863     Vals.push_back(CBI->getCallingConv() << bitc::CALL_CCONV |
2864                    1 << bitc::CALL_EXPLICIT_TYPE);
2865 
2866     Vals.push_back(VE.getValueID(CBI->getDefaultDest()));
2867     Vals.push_back(CBI->getNumIndirectDests());
2868     for (unsigned i = 0, e = CBI->getNumIndirectDests(); i != e; ++i)
2869       Vals.push_back(VE.getValueID(CBI->getIndirectDest(i)));
2870 
2871     Vals.push_back(VE.getTypeID(FTy));
2872     pushValueAndType(Callee, InstID, Vals);
2873 
2874     // Emit value #'s for the fixed parameters.
2875     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
2876       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
2877 
2878     // Emit type/value pairs for varargs params.
2879     if (FTy->isVarArg()) {
2880       for (unsigned i = FTy->getNumParams(), e = CBI->getNumArgOperands();
2881            i != e; ++i)
2882         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
2883     }
2884     break;
2885   }
2886   case Instruction::Unreachable:
2887     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
2888     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
2889     break;
2890 
2891   case Instruction::PHI: {
2892     const PHINode &PN = cast<PHINode>(I);
2893     Code = bitc::FUNC_CODE_INST_PHI;
2894     // With the newer instruction encoding, forward references could give
2895     // negative valued IDs.  This is most common for PHIs, so we use
2896     // signed VBRs.
2897     SmallVector<uint64_t, 128> Vals64;
2898     Vals64.push_back(VE.getTypeID(PN.getType()));
2899     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
2900       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64);
2901       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
2902     }
2903 
2904     uint64_t Flags = getOptimizationFlags(&I);
2905     if (Flags != 0)
2906       Vals64.push_back(Flags);
2907 
2908     // Emit a Vals64 vector and exit.
2909     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
2910     Vals64.clear();
2911     return;
2912   }
2913 
2914   case Instruction::LandingPad: {
2915     const LandingPadInst &LP = cast<LandingPadInst>(I);
2916     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
2917     Vals.push_back(VE.getTypeID(LP.getType()));
2918     Vals.push_back(LP.isCleanup());
2919     Vals.push_back(LP.getNumClauses());
2920     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
2921       if (LP.isCatch(I))
2922         Vals.push_back(LandingPadInst::Catch);
2923       else
2924         Vals.push_back(LandingPadInst::Filter);
2925       pushValueAndType(LP.getClause(I), InstID, Vals);
2926     }
2927     break;
2928   }
2929 
2930   case Instruction::Alloca: {
2931     Code = bitc::FUNC_CODE_INST_ALLOCA;
2932     const AllocaInst &AI = cast<AllocaInst>(I);
2933     Vals.push_back(VE.getTypeID(AI.getAllocatedType()));
2934     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2935     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
2936     unsigned AlignRecord = Log2_32(AI.getAlignment()) + 1;
2937     assert(Log2_32(Value::MaximumAlignment) + 1 < 1 << 5 &&
2938            "not enough bits for maximum alignment");
2939     assert(AlignRecord < 1 << 5 && "alignment greater than 1 << 64");
2940     AlignRecord |= AI.isUsedWithInAlloca() << 5;
2941     AlignRecord |= 1 << 6;
2942     AlignRecord |= AI.isSwiftError() << 7;
2943     Vals.push_back(AlignRecord);
2944     break;
2945   }
2946 
2947   case Instruction::Load:
2948     if (cast<LoadInst>(I).isAtomic()) {
2949       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
2950       pushValueAndType(I.getOperand(0), InstID, Vals);
2951     } else {
2952       Code = bitc::FUNC_CODE_INST_LOAD;
2953       if (!pushValueAndType(I.getOperand(0), InstID, Vals)) // ptr
2954         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
2955     }
2956     Vals.push_back(VE.getTypeID(I.getType()));
2957     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
2958     Vals.push_back(cast<LoadInst>(I).isVolatile());
2959     if (cast<LoadInst>(I).isAtomic()) {
2960       Vals.push_back(getEncodedOrdering(cast<LoadInst>(I).getOrdering()));
2961       Vals.push_back(getEncodedSyncScopeID(cast<LoadInst>(I).getSyncScopeID()));
2962     }
2963     break;
2964   case Instruction::Store:
2965     if (cast<StoreInst>(I).isAtomic())
2966       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
2967     else
2968       Code = bitc::FUNC_CODE_INST_STORE;
2969     pushValueAndType(I.getOperand(1), InstID, Vals); // ptrty + ptr
2970     pushValueAndType(I.getOperand(0), InstID, Vals); // valty + val
2971     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
2972     Vals.push_back(cast<StoreInst>(I).isVolatile());
2973     if (cast<StoreInst>(I).isAtomic()) {
2974       Vals.push_back(getEncodedOrdering(cast<StoreInst>(I).getOrdering()));
2975       Vals.push_back(
2976           getEncodedSyncScopeID(cast<StoreInst>(I).getSyncScopeID()));
2977     }
2978     break;
2979   case Instruction::AtomicCmpXchg:
2980     Code = bitc::FUNC_CODE_INST_CMPXCHG;
2981     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
2982     pushValueAndType(I.getOperand(1), InstID, Vals); // cmp.
2983     pushValue(I.getOperand(2), InstID, Vals);        // newval.
2984     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
2985     Vals.push_back(
2986         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
2987     Vals.push_back(
2988         getEncodedSyncScopeID(cast<AtomicCmpXchgInst>(I).getSyncScopeID()));
2989     Vals.push_back(
2990         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
2991     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
2992     break;
2993   case Instruction::AtomicRMW:
2994     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
2995     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
2996     pushValue(I.getOperand(1), InstID, Vals);        // val.
2997     Vals.push_back(
2998         getEncodedRMWOperation(cast<AtomicRMWInst>(I).getOperation()));
2999     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
3000     Vals.push_back(getEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
3001     Vals.push_back(
3002         getEncodedSyncScopeID(cast<AtomicRMWInst>(I).getSyncScopeID()));
3003     break;
3004   case Instruction::Fence:
3005     Code = bitc::FUNC_CODE_INST_FENCE;
3006     Vals.push_back(getEncodedOrdering(cast<FenceInst>(I).getOrdering()));
3007     Vals.push_back(getEncodedSyncScopeID(cast<FenceInst>(I).getSyncScopeID()));
3008     break;
3009   case Instruction::Call: {
3010     const CallInst &CI = cast<CallInst>(I);
3011     FunctionType *FTy = CI.getFunctionType();
3012 
3013     if (CI.hasOperandBundles())
3014       writeOperandBundles(&CI, InstID);
3015 
3016     Code = bitc::FUNC_CODE_INST_CALL;
3017 
3018     Vals.push_back(VE.getAttributeListID(CI.getAttributes()));
3019 
3020     unsigned Flags = getOptimizationFlags(&I);
3021     Vals.push_back(CI.getCallingConv() << bitc::CALL_CCONV |
3022                    unsigned(CI.isTailCall()) << bitc::CALL_TAIL |
3023                    unsigned(CI.isMustTailCall()) << bitc::CALL_MUSTTAIL |
3024                    1 << bitc::CALL_EXPLICIT_TYPE |
3025                    unsigned(CI.isNoTailCall()) << bitc::CALL_NOTAIL |
3026                    unsigned(Flags != 0) << bitc::CALL_FMF);
3027     if (Flags != 0)
3028       Vals.push_back(Flags);
3029 
3030     Vals.push_back(VE.getTypeID(FTy));
3031     pushValueAndType(CI.getCalledValue(), InstID, Vals); // Callee
3032 
3033     // Emit value #'s for the fixed parameters.
3034     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
3035       // Check for labels (can happen with asm labels).
3036       if (FTy->getParamType(i)->isLabelTy())
3037         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
3038       else
3039         pushValue(CI.getArgOperand(i), InstID, Vals); // fixed param.
3040     }
3041 
3042     // Emit type/value pairs for varargs params.
3043     if (FTy->isVarArg()) {
3044       for (unsigned i = FTy->getNumParams(), e = CI.getNumArgOperands();
3045            i != e; ++i)
3046         pushValueAndType(CI.getArgOperand(i), InstID, Vals); // varargs
3047     }
3048     break;
3049   }
3050   case Instruction::VAArg:
3051     Code = bitc::FUNC_CODE_INST_VAARG;
3052     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
3053     pushValue(I.getOperand(0), InstID, Vals);                   // valist.
3054     Vals.push_back(VE.getTypeID(I.getType())); // restype.
3055     break;
3056   case Instruction::Freeze:
3057     Code = bitc::FUNC_CODE_INST_FREEZE;
3058     pushValueAndType(I.getOperand(0), InstID, Vals);
3059     break;
3060   }
3061 
3062   Stream.EmitRecord(Code, Vals, AbbrevToUse);
3063   Vals.clear();
3064 }
3065 
3066 /// Write a GlobalValue VST to the module. The purpose of this data structure is
3067 /// to allow clients to efficiently find the function body.
3068 void ModuleBitcodeWriter::writeGlobalValueSymbolTable(
3069   DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3070   // Get the offset of the VST we are writing, and backpatch it into
3071   // the VST forward declaration record.
3072   uint64_t VSTOffset = Stream.GetCurrentBitNo();
3073   // The BitcodeStartBit was the stream offset of the identification block.
3074   VSTOffset -= bitcodeStartBit();
3075   assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
3076   // Note that we add 1 here because the offset is relative to one word
3077   // before the start of the identification block, which was historically
3078   // always the start of the regular bitcode header.
3079   Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32 + 1);
3080 
3081   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3082 
3083   auto Abbv = std::make_shared<BitCodeAbbrev>();
3084   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
3085   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
3086   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
3087   unsigned FnEntryAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3088 
3089   for (const Function &F : M) {
3090     uint64_t Record[2];
3091 
3092     if (F.isDeclaration())
3093       continue;
3094 
3095     Record[0] = VE.getValueID(&F);
3096 
3097     // Save the word offset of the function (from the start of the
3098     // actual bitcode written to the stream).
3099     uint64_t BitcodeIndex = FunctionToBitcodeIndex[&F] - bitcodeStartBit();
3100     assert((BitcodeIndex & 31) == 0 && "function block not 32-bit aligned");
3101     // Note that we add 1 here because the offset is relative to one word
3102     // before the start of the identification block, which was historically
3103     // always the start of the regular bitcode header.
3104     Record[1] = BitcodeIndex / 32 + 1;
3105 
3106     Stream.EmitRecord(bitc::VST_CODE_FNENTRY, Record, FnEntryAbbrev);
3107   }
3108 
3109   Stream.ExitBlock();
3110 }
3111 
3112 /// Emit names for arguments, instructions and basic blocks in a function.
3113 void ModuleBitcodeWriter::writeFunctionLevelValueSymbolTable(
3114     const ValueSymbolTable &VST) {
3115   if (VST.empty())
3116     return;
3117 
3118   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3119 
3120   // FIXME: Set up the abbrev, we know how many values there are!
3121   // FIXME: We know if the type names can use 7-bit ascii.
3122   SmallVector<uint64_t, 64> NameVals;
3123 
3124   for (const ValueName &Name : VST) {
3125     // Figure out the encoding to use for the name.
3126     StringEncoding Bits = getStringEncoding(Name.getKey());
3127 
3128     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
3129     NameVals.push_back(VE.getValueID(Name.getValue()));
3130 
3131     // VST_CODE_ENTRY:   [valueid, namechar x N]
3132     // VST_CODE_BBENTRY: [bbid, namechar x N]
3133     unsigned Code;
3134     if (isa<BasicBlock>(Name.getValue())) {
3135       Code = bitc::VST_CODE_BBENTRY;
3136       if (Bits == SE_Char6)
3137         AbbrevToUse = VST_BBENTRY_6_ABBREV;
3138     } else {
3139       Code = bitc::VST_CODE_ENTRY;
3140       if (Bits == SE_Char6)
3141         AbbrevToUse = VST_ENTRY_6_ABBREV;
3142       else if (Bits == SE_Fixed7)
3143         AbbrevToUse = VST_ENTRY_7_ABBREV;
3144     }
3145 
3146     for (const auto P : Name.getKey())
3147       NameVals.push_back((unsigned char)P);
3148 
3149     // Emit the finished record.
3150     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
3151     NameVals.clear();
3152   }
3153 
3154   Stream.ExitBlock();
3155 }
3156 
3157 void ModuleBitcodeWriter::writeUseList(UseListOrder &&Order) {
3158   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
3159   unsigned Code;
3160   if (isa<BasicBlock>(Order.V))
3161     Code = bitc::USELIST_CODE_BB;
3162   else
3163     Code = bitc::USELIST_CODE_DEFAULT;
3164 
3165   SmallVector<uint64_t, 64> Record(Order.Shuffle.begin(), Order.Shuffle.end());
3166   Record.push_back(VE.getValueID(Order.V));
3167   Stream.EmitRecord(Code, Record);
3168 }
3169 
3170 void ModuleBitcodeWriter::writeUseListBlock(const Function *F) {
3171   assert(VE.shouldPreserveUseListOrder() &&
3172          "Expected to be preserving use-list order");
3173 
3174   auto hasMore = [&]() {
3175     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
3176   };
3177   if (!hasMore())
3178     // Nothing to do.
3179     return;
3180 
3181   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
3182   while (hasMore()) {
3183     writeUseList(std::move(VE.UseListOrders.back()));
3184     VE.UseListOrders.pop_back();
3185   }
3186   Stream.ExitBlock();
3187 }
3188 
3189 /// Emit a function body to the module stream.
3190 void ModuleBitcodeWriter::writeFunction(
3191     const Function &F,
3192     DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3193   // Save the bitcode index of the start of this function block for recording
3194   // in the VST.
3195   FunctionToBitcodeIndex[&F] = Stream.GetCurrentBitNo();
3196 
3197   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
3198   VE.incorporateFunction(F);
3199 
3200   SmallVector<unsigned, 64> Vals;
3201 
3202   // Emit the number of basic blocks, so the reader can create them ahead of
3203   // time.
3204   Vals.push_back(VE.getBasicBlocks().size());
3205   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
3206   Vals.clear();
3207 
3208   // If there are function-local constants, emit them now.
3209   unsigned CstStart, CstEnd;
3210   VE.getFunctionConstantRange(CstStart, CstEnd);
3211   writeConstants(CstStart, CstEnd, false);
3212 
3213   // If there is function-local metadata, emit it now.
3214   writeFunctionMetadata(F);
3215 
3216   // Keep a running idea of what the instruction ID is.
3217   unsigned InstID = CstEnd;
3218 
3219   bool NeedsMetadataAttachment = F.hasMetadata();
3220 
3221   DILocation *LastDL = nullptr;
3222   // Finally, emit all the instructions, in order.
3223   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
3224     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
3225          I != E; ++I) {
3226       writeInstruction(*I, InstID, Vals);
3227 
3228       if (!I->getType()->isVoidTy())
3229         ++InstID;
3230 
3231       // If the instruction has metadata, write a metadata attachment later.
3232       NeedsMetadataAttachment |= I->hasMetadataOtherThanDebugLoc();
3233 
3234       // If the instruction has a debug location, emit it.
3235       DILocation *DL = I->getDebugLoc();
3236       if (!DL)
3237         continue;
3238 
3239       if (DL == LastDL) {
3240         // Just repeat the same debug loc as last time.
3241         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
3242         continue;
3243       }
3244 
3245       Vals.push_back(DL->getLine());
3246       Vals.push_back(DL->getColumn());
3247       Vals.push_back(VE.getMetadataOrNullID(DL->getScope()));
3248       Vals.push_back(VE.getMetadataOrNullID(DL->getInlinedAt()));
3249       Vals.push_back(DL->isImplicitCode());
3250       Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
3251       Vals.clear();
3252 
3253       LastDL = DL;
3254     }
3255 
3256   // Emit names for all the instructions etc.
3257   if (auto *Symtab = F.getValueSymbolTable())
3258     writeFunctionLevelValueSymbolTable(*Symtab);
3259 
3260   if (NeedsMetadataAttachment)
3261     writeFunctionMetadataAttachment(F);
3262   if (VE.shouldPreserveUseListOrder())
3263     writeUseListBlock(&F);
3264   VE.purgeFunction();
3265   Stream.ExitBlock();
3266 }
3267 
3268 // Emit blockinfo, which defines the standard abbreviations etc.
3269 void ModuleBitcodeWriter::writeBlockInfo() {
3270   // We only want to emit block info records for blocks that have multiple
3271   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
3272   // Other blocks can define their abbrevs inline.
3273   Stream.EnterBlockInfoBlock();
3274 
3275   { // 8-bit fixed-width VST_CODE_ENTRY/VST_CODE_BBENTRY strings.
3276     auto Abbv = std::make_shared<BitCodeAbbrev>();
3277     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
3278     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3279     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3280     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3281     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3282         VST_ENTRY_8_ABBREV)
3283       llvm_unreachable("Unexpected abbrev ordering!");
3284   }
3285 
3286   { // 7-bit fixed width VST_CODE_ENTRY strings.
3287     auto Abbv = std::make_shared<BitCodeAbbrev>();
3288     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3289     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3290     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3291     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3292     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3293         VST_ENTRY_7_ABBREV)
3294       llvm_unreachable("Unexpected abbrev ordering!");
3295   }
3296   { // 6-bit char6 VST_CODE_ENTRY strings.
3297     auto Abbv = std::make_shared<BitCodeAbbrev>();
3298     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3299     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3300     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3301     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3302     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3303         VST_ENTRY_6_ABBREV)
3304       llvm_unreachable("Unexpected abbrev ordering!");
3305   }
3306   { // 6-bit char6 VST_CODE_BBENTRY strings.
3307     auto Abbv = std::make_shared<BitCodeAbbrev>();
3308     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
3309     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3310     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3311     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3312     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3313         VST_BBENTRY_6_ABBREV)
3314       llvm_unreachable("Unexpected abbrev ordering!");
3315   }
3316 
3317   { // SETTYPE abbrev for CONSTANTS_BLOCK.
3318     auto Abbv = std::make_shared<BitCodeAbbrev>();
3319     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
3320     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
3321                               VE.computeBitsRequiredForTypeIndicies()));
3322     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3323         CONSTANTS_SETTYPE_ABBREV)
3324       llvm_unreachable("Unexpected abbrev ordering!");
3325   }
3326 
3327   { // INTEGER abbrev for CONSTANTS_BLOCK.
3328     auto Abbv = std::make_shared<BitCodeAbbrev>();
3329     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
3330     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3331     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3332         CONSTANTS_INTEGER_ABBREV)
3333       llvm_unreachable("Unexpected abbrev ordering!");
3334   }
3335 
3336   { // CE_CAST abbrev for CONSTANTS_BLOCK.
3337     auto Abbv = std::make_shared<BitCodeAbbrev>();
3338     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
3339     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
3340     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
3341                               VE.computeBitsRequiredForTypeIndicies()));
3342     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
3343 
3344     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3345         CONSTANTS_CE_CAST_Abbrev)
3346       llvm_unreachable("Unexpected abbrev ordering!");
3347   }
3348   { // NULL abbrev for CONSTANTS_BLOCK.
3349     auto Abbv = std::make_shared<BitCodeAbbrev>();
3350     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
3351     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3352         CONSTANTS_NULL_Abbrev)
3353       llvm_unreachable("Unexpected abbrev ordering!");
3354   }
3355 
3356   // FIXME: This should only use space for first class types!
3357 
3358   { // INST_LOAD abbrev for FUNCTION_BLOCK.
3359     auto Abbv = std::make_shared<BitCodeAbbrev>();
3360     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
3361     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
3362     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
3363                               VE.computeBitsRequiredForTypeIndicies()));
3364     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
3365     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
3366     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3367         FUNCTION_INST_LOAD_ABBREV)
3368       llvm_unreachable("Unexpected abbrev ordering!");
3369   }
3370   { // INST_UNOP abbrev for FUNCTION_BLOCK.
3371     auto Abbv = std::make_shared<BitCodeAbbrev>();
3372     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3373     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3374     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3375     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3376         FUNCTION_INST_UNOP_ABBREV)
3377       llvm_unreachable("Unexpected abbrev ordering!");
3378   }
3379   { // INST_UNOP_FLAGS abbrev for FUNCTION_BLOCK.
3380     auto Abbv = std::make_shared<BitCodeAbbrev>();
3381     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3382     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3383     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3384     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3385     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3386         FUNCTION_INST_UNOP_FLAGS_ABBREV)
3387       llvm_unreachable("Unexpected abbrev ordering!");
3388   }
3389   { // INST_BINOP abbrev for FUNCTION_BLOCK.
3390     auto Abbv = std::make_shared<BitCodeAbbrev>();
3391     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3392     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3393     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3394     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3395     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3396         FUNCTION_INST_BINOP_ABBREV)
3397       llvm_unreachable("Unexpected abbrev ordering!");
3398   }
3399   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
3400     auto Abbv = std::make_shared<BitCodeAbbrev>();
3401     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3402     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3403     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3404     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3405     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3406     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3407         FUNCTION_INST_BINOP_FLAGS_ABBREV)
3408       llvm_unreachable("Unexpected abbrev ordering!");
3409   }
3410   { // INST_CAST abbrev for FUNCTION_BLOCK.
3411     auto Abbv = std::make_shared<BitCodeAbbrev>();
3412     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
3413     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
3414     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
3415                               VE.computeBitsRequiredForTypeIndicies()));
3416     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
3417     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3418         FUNCTION_INST_CAST_ABBREV)
3419       llvm_unreachable("Unexpected abbrev ordering!");
3420   }
3421 
3422   { // INST_RET abbrev for FUNCTION_BLOCK.
3423     auto Abbv = std::make_shared<BitCodeAbbrev>();
3424     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3425     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3426         FUNCTION_INST_RET_VOID_ABBREV)
3427       llvm_unreachable("Unexpected abbrev ordering!");
3428   }
3429   { // INST_RET abbrev for FUNCTION_BLOCK.
3430     auto Abbv = std::make_shared<BitCodeAbbrev>();
3431     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3432     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
3433     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3434         FUNCTION_INST_RET_VAL_ABBREV)
3435       llvm_unreachable("Unexpected abbrev ordering!");
3436   }
3437   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
3438     auto Abbv = std::make_shared<BitCodeAbbrev>();
3439     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
3440     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3441         FUNCTION_INST_UNREACHABLE_ABBREV)
3442       llvm_unreachable("Unexpected abbrev ordering!");
3443   }
3444   {
3445     auto Abbv = std::make_shared<BitCodeAbbrev>();
3446     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_GEP));
3447     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
3448     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, // dest ty
3449                               Log2_32_Ceil(VE.getTypes().size() + 1)));
3450     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3451     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
3452     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3453         FUNCTION_INST_GEP_ABBREV)
3454       llvm_unreachable("Unexpected abbrev ordering!");
3455   }
3456 
3457   Stream.ExitBlock();
3458 }
3459 
3460 /// Write the module path strings, currently only used when generating
3461 /// a combined index file.
3462 void IndexBitcodeWriter::writeModStrings() {
3463   Stream.EnterSubblock(bitc::MODULE_STRTAB_BLOCK_ID, 3);
3464 
3465   // TODO: See which abbrev sizes we actually need to emit
3466 
3467   // 8-bit fixed-width MST_ENTRY strings.
3468   auto Abbv = std::make_shared<BitCodeAbbrev>();
3469   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3470   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3471   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3472   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3473   unsigned Abbrev8Bit = Stream.EmitAbbrev(std::move(Abbv));
3474 
3475   // 7-bit fixed width MST_ENTRY strings.
3476   Abbv = std::make_shared<BitCodeAbbrev>();
3477   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3478   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3479   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3480   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3481   unsigned Abbrev7Bit = Stream.EmitAbbrev(std::move(Abbv));
3482 
3483   // 6-bit char6 MST_ENTRY strings.
3484   Abbv = std::make_shared<BitCodeAbbrev>();
3485   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3486   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3487   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3488   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3489   unsigned Abbrev6Bit = Stream.EmitAbbrev(std::move(Abbv));
3490 
3491   // Module Hash, 160 bits SHA1. Optionally, emitted after each MST_CODE_ENTRY.
3492   Abbv = std::make_shared<BitCodeAbbrev>();
3493   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_HASH));
3494   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3495   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3496   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3497   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3498   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3499   unsigned AbbrevHash = Stream.EmitAbbrev(std::move(Abbv));
3500 
3501   SmallVector<unsigned, 64> Vals;
3502   forEachModule(
3503       [&](const StringMapEntry<std::pair<uint64_t, ModuleHash>> &MPSE) {
3504         StringRef Key = MPSE.getKey();
3505         const auto &Value = MPSE.getValue();
3506         StringEncoding Bits = getStringEncoding(Key);
3507         unsigned AbbrevToUse = Abbrev8Bit;
3508         if (Bits == SE_Char6)
3509           AbbrevToUse = Abbrev6Bit;
3510         else if (Bits == SE_Fixed7)
3511           AbbrevToUse = Abbrev7Bit;
3512 
3513         Vals.push_back(Value.first);
3514         Vals.append(Key.begin(), Key.end());
3515 
3516         // Emit the finished record.
3517         Stream.EmitRecord(bitc::MST_CODE_ENTRY, Vals, AbbrevToUse);
3518 
3519         // Emit an optional hash for the module now
3520         const auto &Hash = Value.second;
3521         if (llvm::any_of(Hash, [](uint32_t H) { return H; })) {
3522           Vals.assign(Hash.begin(), Hash.end());
3523           // Emit the hash record.
3524           Stream.EmitRecord(bitc::MST_CODE_HASH, Vals, AbbrevHash);
3525         }
3526 
3527         Vals.clear();
3528       });
3529   Stream.ExitBlock();
3530 }
3531 
3532 /// Write the function type metadata related records that need to appear before
3533 /// a function summary entry (whether per-module or combined).
3534 static void writeFunctionTypeMetadataRecords(BitstreamWriter &Stream,
3535                                              FunctionSummary *FS) {
3536   if (!FS->type_tests().empty())
3537     Stream.EmitRecord(bitc::FS_TYPE_TESTS, FS->type_tests());
3538 
3539   SmallVector<uint64_t, 64> Record;
3540 
3541   auto WriteVFuncIdVec = [&](uint64_t Ty,
3542                              ArrayRef<FunctionSummary::VFuncId> VFs) {
3543     if (VFs.empty())
3544       return;
3545     Record.clear();
3546     for (auto &VF : VFs) {
3547       Record.push_back(VF.GUID);
3548       Record.push_back(VF.Offset);
3549     }
3550     Stream.EmitRecord(Ty, Record);
3551   };
3552 
3553   WriteVFuncIdVec(bitc::FS_TYPE_TEST_ASSUME_VCALLS,
3554                   FS->type_test_assume_vcalls());
3555   WriteVFuncIdVec(bitc::FS_TYPE_CHECKED_LOAD_VCALLS,
3556                   FS->type_checked_load_vcalls());
3557 
3558   auto WriteConstVCallVec = [&](uint64_t Ty,
3559                                 ArrayRef<FunctionSummary::ConstVCall> VCs) {
3560     for (auto &VC : VCs) {
3561       Record.clear();
3562       Record.push_back(VC.VFunc.GUID);
3563       Record.push_back(VC.VFunc.Offset);
3564       Record.insert(Record.end(), VC.Args.begin(), VC.Args.end());
3565       Stream.EmitRecord(Ty, Record);
3566     }
3567   };
3568 
3569   WriteConstVCallVec(bitc::FS_TYPE_TEST_ASSUME_CONST_VCALL,
3570                      FS->type_test_assume_const_vcalls());
3571   WriteConstVCallVec(bitc::FS_TYPE_CHECKED_LOAD_CONST_VCALL,
3572                      FS->type_checked_load_const_vcalls());
3573 }
3574 
3575 /// Collect type IDs from type tests used by function.
3576 static void
3577 getReferencedTypeIds(FunctionSummary *FS,
3578                      std::set<GlobalValue::GUID> &ReferencedTypeIds) {
3579   if (!FS->type_tests().empty())
3580     for (auto &TT : FS->type_tests())
3581       ReferencedTypeIds.insert(TT);
3582 
3583   auto GetReferencedTypesFromVFuncIdVec =
3584       [&](ArrayRef<FunctionSummary::VFuncId> VFs) {
3585         for (auto &VF : VFs)
3586           ReferencedTypeIds.insert(VF.GUID);
3587       };
3588 
3589   GetReferencedTypesFromVFuncIdVec(FS->type_test_assume_vcalls());
3590   GetReferencedTypesFromVFuncIdVec(FS->type_checked_load_vcalls());
3591 
3592   auto GetReferencedTypesFromConstVCallVec =
3593       [&](ArrayRef<FunctionSummary::ConstVCall> VCs) {
3594         for (auto &VC : VCs)
3595           ReferencedTypeIds.insert(VC.VFunc.GUID);
3596       };
3597 
3598   GetReferencedTypesFromConstVCallVec(FS->type_test_assume_const_vcalls());
3599   GetReferencedTypesFromConstVCallVec(FS->type_checked_load_const_vcalls());
3600 }
3601 
3602 static void writeWholeProgramDevirtResolutionByArg(
3603     SmallVector<uint64_t, 64> &NameVals, const std::vector<uint64_t> &args,
3604     const WholeProgramDevirtResolution::ByArg &ByArg) {
3605   NameVals.push_back(args.size());
3606   NameVals.insert(NameVals.end(), args.begin(), args.end());
3607 
3608   NameVals.push_back(ByArg.TheKind);
3609   NameVals.push_back(ByArg.Info);
3610   NameVals.push_back(ByArg.Byte);
3611   NameVals.push_back(ByArg.Bit);
3612 }
3613 
3614 static void writeWholeProgramDevirtResolution(
3615     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3616     uint64_t Id, const WholeProgramDevirtResolution &Wpd) {
3617   NameVals.push_back(Id);
3618 
3619   NameVals.push_back(Wpd.TheKind);
3620   NameVals.push_back(StrtabBuilder.add(Wpd.SingleImplName));
3621   NameVals.push_back(Wpd.SingleImplName.size());
3622 
3623   NameVals.push_back(Wpd.ResByArg.size());
3624   for (auto &A : Wpd.ResByArg)
3625     writeWholeProgramDevirtResolutionByArg(NameVals, A.first, A.second);
3626 }
3627 
3628 static void writeTypeIdSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
3629                                      StringTableBuilder &StrtabBuilder,
3630                                      const std::string &Id,
3631                                      const TypeIdSummary &Summary) {
3632   NameVals.push_back(StrtabBuilder.add(Id));
3633   NameVals.push_back(Id.size());
3634 
3635   NameVals.push_back(Summary.TTRes.TheKind);
3636   NameVals.push_back(Summary.TTRes.SizeM1BitWidth);
3637   NameVals.push_back(Summary.TTRes.AlignLog2);
3638   NameVals.push_back(Summary.TTRes.SizeM1);
3639   NameVals.push_back(Summary.TTRes.BitMask);
3640   NameVals.push_back(Summary.TTRes.InlineBits);
3641 
3642   for (auto &W : Summary.WPDRes)
3643     writeWholeProgramDevirtResolution(NameVals, StrtabBuilder, W.first,
3644                                       W.second);
3645 }
3646 
3647 static void writeTypeIdCompatibleVtableSummaryRecord(
3648     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3649     const std::string &Id, const TypeIdCompatibleVtableInfo &Summary,
3650     ValueEnumerator &VE) {
3651   NameVals.push_back(StrtabBuilder.add(Id));
3652   NameVals.push_back(Id.size());
3653 
3654   for (auto &P : Summary) {
3655     NameVals.push_back(P.AddressPointOffset);
3656     NameVals.push_back(VE.getValueID(P.VTableVI.getValue()));
3657   }
3658 }
3659 
3660 // Helper to emit a single function summary record.
3661 void ModuleBitcodeWriterBase::writePerModuleFunctionSummaryRecord(
3662     SmallVector<uint64_t, 64> &NameVals, GlobalValueSummary *Summary,
3663     unsigned ValueID, unsigned FSCallsAbbrev, unsigned FSCallsProfileAbbrev,
3664     const Function &F) {
3665   NameVals.push_back(ValueID);
3666 
3667   FunctionSummary *FS = cast<FunctionSummary>(Summary);
3668   writeFunctionTypeMetadataRecords(Stream, FS);
3669 
3670   auto SpecialRefCnts = FS->specialRefCounts();
3671   NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
3672   NameVals.push_back(FS->instCount());
3673   NameVals.push_back(getEncodedFFlags(FS->fflags()));
3674   NameVals.push_back(FS->refs().size());
3675   NameVals.push_back(SpecialRefCnts.first);  // rorefcnt
3676   NameVals.push_back(SpecialRefCnts.second); // worefcnt
3677 
3678   for (auto &RI : FS->refs())
3679     NameVals.push_back(VE.getValueID(RI.getValue()));
3680 
3681   bool HasProfileData =
3682       F.hasProfileData() || ForceSummaryEdgesCold != FunctionSummary::FSHT_None;
3683   for (auto &ECI : FS->calls()) {
3684     NameVals.push_back(getValueId(ECI.first));
3685     if (HasProfileData)
3686       NameVals.push_back(static_cast<uint8_t>(ECI.second.Hotness));
3687     else if (WriteRelBFToSummary)
3688       NameVals.push_back(ECI.second.RelBlockFreq);
3689   }
3690 
3691   unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
3692   unsigned Code =
3693       (HasProfileData ? bitc::FS_PERMODULE_PROFILE
3694                       : (WriteRelBFToSummary ? bitc::FS_PERMODULE_RELBF
3695                                              : bitc::FS_PERMODULE));
3696 
3697   // Emit the finished record.
3698   Stream.EmitRecord(Code, NameVals, FSAbbrev);
3699   NameVals.clear();
3700 }
3701 
3702 // Collect the global value references in the given variable's initializer,
3703 // and emit them in a summary record.
3704 void ModuleBitcodeWriterBase::writeModuleLevelReferences(
3705     const GlobalVariable &V, SmallVector<uint64_t, 64> &NameVals,
3706     unsigned FSModRefsAbbrev, unsigned FSModVTableRefsAbbrev) {
3707   auto VI = Index->getValueInfo(V.getGUID());
3708   if (!VI || VI.getSummaryList().empty()) {
3709     // Only declarations should not have a summary (a declaration might however
3710     // have a summary if the def was in module level asm).
3711     assert(V.isDeclaration());
3712     return;
3713   }
3714   auto *Summary = VI.getSummaryList()[0].get();
3715   NameVals.push_back(VE.getValueID(&V));
3716   GlobalVarSummary *VS = cast<GlobalVarSummary>(Summary);
3717   NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
3718   NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
3719 
3720   auto VTableFuncs = VS->vTableFuncs();
3721   if (!VTableFuncs.empty())
3722     NameVals.push_back(VS->refs().size());
3723 
3724   unsigned SizeBeforeRefs = NameVals.size();
3725   for (auto &RI : VS->refs())
3726     NameVals.push_back(VE.getValueID(RI.getValue()));
3727   // Sort the refs for determinism output, the vector returned by FS->refs() has
3728   // been initialized from a DenseSet.
3729   llvm::sort(NameVals.begin() + SizeBeforeRefs, NameVals.end());
3730 
3731   if (VTableFuncs.empty())
3732     Stream.EmitRecord(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS, NameVals,
3733                       FSModRefsAbbrev);
3734   else {
3735     // VTableFuncs pairs should already be sorted by offset.
3736     for (auto &P : VTableFuncs) {
3737       NameVals.push_back(VE.getValueID(P.FuncVI.getValue()));
3738       NameVals.push_back(P.VTableOffset);
3739     }
3740 
3741     Stream.EmitRecord(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS, NameVals,
3742                       FSModVTableRefsAbbrev);
3743   }
3744   NameVals.clear();
3745 }
3746 
3747 /// Emit the per-module summary section alongside the rest of
3748 /// the module's bitcode.
3749 void ModuleBitcodeWriterBase::writePerModuleGlobalValueSummary() {
3750   // By default we compile with ThinLTO if the module has a summary, but the
3751   // client can request full LTO with a module flag.
3752   bool IsThinLTO = true;
3753   if (auto *MD =
3754           mdconst::extract_or_null<ConstantInt>(M.getModuleFlag("ThinLTO")))
3755     IsThinLTO = MD->getZExtValue();
3756   Stream.EnterSubblock(IsThinLTO ? bitc::GLOBALVAL_SUMMARY_BLOCK_ID
3757                                  : bitc::FULL_LTO_GLOBALVAL_SUMMARY_BLOCK_ID,
3758                        4);
3759 
3760   Stream.EmitRecord(
3761       bitc::FS_VERSION,
3762       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
3763 
3764   // Write the index flags.
3765   uint64_t Flags = 0;
3766   // Bits 1-3 are set only in the combined index, skip them.
3767   if (Index->enableSplitLTOUnit())
3768     Flags |= 0x8;
3769   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Flags});
3770 
3771   if (Index->begin() == Index->end()) {
3772     Stream.ExitBlock();
3773     return;
3774   }
3775 
3776   for (const auto &GVI : valueIds()) {
3777     Stream.EmitRecord(bitc::FS_VALUE_GUID,
3778                       ArrayRef<uint64_t>{GVI.second, GVI.first});
3779   }
3780 
3781   // Abbrev for FS_PERMODULE_PROFILE.
3782   auto Abbv = std::make_shared<BitCodeAbbrev>();
3783   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_PROFILE));
3784   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3785   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3786   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3787   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3788   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3789   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
3790   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
3791   // numrefs x valueid, n x (valueid, hotness)
3792   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3793   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3794   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3795 
3796   // Abbrev for FS_PERMODULE or FS_PERMODULE_RELBF.
3797   Abbv = std::make_shared<BitCodeAbbrev>();
3798   if (WriteRelBFToSummary)
3799     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_RELBF));
3800   else
3801     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE));
3802   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3803   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3804   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3805   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3806   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3807   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
3808   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
3809   // numrefs x valueid, n x (valueid [, rel_block_freq])
3810   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3811   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3812   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3813 
3814   // Abbrev for FS_PERMODULE_GLOBALVAR_INIT_REFS.
3815   Abbv = std::make_shared<BitCodeAbbrev>();
3816   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS));
3817   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
3818   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
3819   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));  // valueids
3820   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3821   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3822 
3823   // Abbrev for FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS.
3824   Abbv = std::make_shared<BitCodeAbbrev>();
3825   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS));
3826   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
3827   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
3828   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numrefs
3829   // numrefs x valueid, n x (valueid , offset)
3830   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3831   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3832   unsigned FSModVTableRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3833 
3834   // Abbrev for FS_ALIAS.
3835   Abbv = std::make_shared<BitCodeAbbrev>();
3836   Abbv->Add(BitCodeAbbrevOp(bitc::FS_ALIAS));
3837   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3838   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3839   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3840   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3841 
3842   // Abbrev for FS_TYPE_ID_METADATA
3843   Abbv = std::make_shared<BitCodeAbbrev>();
3844   Abbv->Add(BitCodeAbbrevOp(bitc::FS_TYPE_ID_METADATA));
3845   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid strtab index
3846   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid length
3847   // n x (valueid , offset)
3848   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3849   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3850   unsigned TypeIdCompatibleVtableAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3851 
3852   SmallVector<uint64_t, 64> NameVals;
3853   // Iterate over the list of functions instead of the Index to
3854   // ensure the ordering is stable.
3855   for (const Function &F : M) {
3856     // Summary emission does not support anonymous functions, they have to
3857     // renamed using the anonymous function renaming pass.
3858     if (!F.hasName())
3859       report_fatal_error("Unexpected anonymous function when writing summary");
3860 
3861     ValueInfo VI = Index->getValueInfo(F.getGUID());
3862     if (!VI || VI.getSummaryList().empty()) {
3863       // Only declarations should not have a summary (a declaration might
3864       // however have a summary if the def was in module level asm).
3865       assert(F.isDeclaration());
3866       continue;
3867     }
3868     auto *Summary = VI.getSummaryList()[0].get();
3869     writePerModuleFunctionSummaryRecord(NameVals, Summary, VE.getValueID(&F),
3870                                         FSCallsAbbrev, FSCallsProfileAbbrev, F);
3871   }
3872 
3873   // Capture references from GlobalVariable initializers, which are outside
3874   // of a function scope.
3875   for (const GlobalVariable &G : M.globals())
3876     writeModuleLevelReferences(G, NameVals, FSModRefsAbbrev,
3877                                FSModVTableRefsAbbrev);
3878 
3879   for (const GlobalAlias &A : M.aliases()) {
3880     auto *Aliasee = A.getBaseObject();
3881     if (!Aliasee->hasName())
3882       // Nameless function don't have an entry in the summary, skip it.
3883       continue;
3884     auto AliasId = VE.getValueID(&A);
3885     auto AliaseeId = VE.getValueID(Aliasee);
3886     NameVals.push_back(AliasId);
3887     auto *Summary = Index->getGlobalValueSummary(A);
3888     AliasSummary *AS = cast<AliasSummary>(Summary);
3889     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
3890     NameVals.push_back(AliaseeId);
3891     Stream.EmitRecord(bitc::FS_ALIAS, NameVals, FSAliasAbbrev);
3892     NameVals.clear();
3893   }
3894 
3895   for (auto &S : Index->typeIdCompatibleVtableMap()) {
3896     writeTypeIdCompatibleVtableSummaryRecord(NameVals, StrtabBuilder, S.first,
3897                                              S.second, VE);
3898     Stream.EmitRecord(bitc::FS_TYPE_ID_METADATA, NameVals,
3899                       TypeIdCompatibleVtableAbbrev);
3900     NameVals.clear();
3901   }
3902 
3903   Stream.ExitBlock();
3904 }
3905 
3906 /// Emit the combined summary section into the combined index file.
3907 void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
3908   Stream.EnterSubblock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID, 3);
3909   Stream.EmitRecord(
3910       bitc::FS_VERSION,
3911       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
3912 
3913   // Write the index flags.
3914   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Index.getFlags()});
3915 
3916   for (const auto &GVI : valueIds()) {
3917     Stream.EmitRecord(bitc::FS_VALUE_GUID,
3918                       ArrayRef<uint64_t>{GVI.second, GVI.first});
3919   }
3920 
3921   // Abbrev for FS_COMBINED.
3922   auto Abbv = std::make_shared<BitCodeAbbrev>();
3923   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED));
3924   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3925   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3926   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3927   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3928   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3929   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
3930   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3931   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
3932   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
3933   // numrefs x valueid, n x (valueid)
3934   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3935   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3936   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3937 
3938   // Abbrev for FS_COMBINED_PROFILE.
3939   Abbv = std::make_shared<BitCodeAbbrev>();
3940   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_PROFILE));
3941   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3942   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3943   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3944   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3945   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3946   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
3947   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3948   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
3949   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
3950   // numrefs x valueid, n x (valueid, hotness)
3951   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3952   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3953   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3954 
3955   // Abbrev for FS_COMBINED_GLOBALVAR_INIT_REFS.
3956   Abbv = std::make_shared<BitCodeAbbrev>();
3957   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS));
3958   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3959   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3960   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3961   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));    // valueids
3962   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3963   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3964 
3965   // Abbrev for FS_COMBINED_ALIAS.
3966   Abbv = std::make_shared<BitCodeAbbrev>();
3967   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_ALIAS));
3968   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3969   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3970   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3971   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3972   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3973 
3974   // The aliases are emitted as a post-pass, and will point to the value
3975   // id of the aliasee. Save them in a vector for post-processing.
3976   SmallVector<AliasSummary *, 64> Aliases;
3977 
3978   // Save the value id for each summary for alias emission.
3979   DenseMap<const GlobalValueSummary *, unsigned> SummaryToValueIdMap;
3980 
3981   SmallVector<uint64_t, 64> NameVals;
3982 
3983   // Set that will be populated during call to writeFunctionTypeMetadataRecords
3984   // with the type ids referenced by this index file.
3985   std::set<GlobalValue::GUID> ReferencedTypeIds;
3986 
3987   // For local linkage, we also emit the original name separately
3988   // immediately after the record.
3989   auto MaybeEmitOriginalName = [&](GlobalValueSummary &S) {
3990     if (!GlobalValue::isLocalLinkage(S.linkage()))
3991       return;
3992     NameVals.push_back(S.getOriginalName());
3993     Stream.EmitRecord(bitc::FS_COMBINED_ORIGINAL_NAME, NameVals);
3994     NameVals.clear();
3995   };
3996 
3997   std::set<GlobalValue::GUID> DefOrUseGUIDs;
3998   forEachSummary([&](GVInfo I, bool IsAliasee) {
3999     GlobalValueSummary *S = I.second;
4000     assert(S);
4001     DefOrUseGUIDs.insert(I.first);
4002     for (const ValueInfo &VI : S->refs())
4003       DefOrUseGUIDs.insert(VI.getGUID());
4004 
4005     auto ValueId = getValueId(I.first);
4006     assert(ValueId);
4007     SummaryToValueIdMap[S] = *ValueId;
4008 
4009     // If this is invoked for an aliasee, we want to record the above
4010     // mapping, but then not emit a summary entry (if the aliasee is
4011     // to be imported, we will invoke this separately with IsAliasee=false).
4012     if (IsAliasee)
4013       return;
4014 
4015     if (auto *AS = dyn_cast<AliasSummary>(S)) {
4016       // Will process aliases as a post-pass because the reader wants all
4017       // global to be loaded first.
4018       Aliases.push_back(AS);
4019       return;
4020     }
4021 
4022     if (auto *VS = dyn_cast<GlobalVarSummary>(S)) {
4023       NameVals.push_back(*ValueId);
4024       NameVals.push_back(Index.getModuleId(VS->modulePath()));
4025       NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
4026       NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
4027       for (auto &RI : VS->refs()) {
4028         auto RefValueId = getValueId(RI.getGUID());
4029         if (!RefValueId)
4030           continue;
4031         NameVals.push_back(*RefValueId);
4032       }
4033 
4034       // Emit the finished record.
4035       Stream.EmitRecord(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS, NameVals,
4036                         FSModRefsAbbrev);
4037       NameVals.clear();
4038       MaybeEmitOriginalName(*S);
4039       return;
4040     }
4041 
4042     auto *FS = cast<FunctionSummary>(S);
4043     writeFunctionTypeMetadataRecords(Stream, FS);
4044     getReferencedTypeIds(FS, ReferencedTypeIds);
4045 
4046     NameVals.push_back(*ValueId);
4047     NameVals.push_back(Index.getModuleId(FS->modulePath()));
4048     NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
4049     NameVals.push_back(FS->instCount());
4050     NameVals.push_back(getEncodedFFlags(FS->fflags()));
4051     NameVals.push_back(FS->entryCount());
4052 
4053     // Fill in below
4054     NameVals.push_back(0); // numrefs
4055     NameVals.push_back(0); // rorefcnt
4056     NameVals.push_back(0); // worefcnt
4057 
4058     unsigned Count = 0, RORefCnt = 0, WORefCnt = 0;
4059     for (auto &RI : FS->refs()) {
4060       auto RefValueId = getValueId(RI.getGUID());
4061       if (!RefValueId)
4062         continue;
4063       NameVals.push_back(*RefValueId);
4064       if (RI.isReadOnly())
4065         RORefCnt++;
4066       else if (RI.isWriteOnly())
4067         WORefCnt++;
4068       Count++;
4069     }
4070     NameVals[6] = Count;
4071     NameVals[7] = RORefCnt;
4072     NameVals[8] = WORefCnt;
4073 
4074     bool HasProfileData = false;
4075     for (auto &EI : FS->calls()) {
4076       HasProfileData |=
4077           EI.second.getHotness() != CalleeInfo::HotnessType::Unknown;
4078       if (HasProfileData)
4079         break;
4080     }
4081 
4082     for (auto &EI : FS->calls()) {
4083       // If this GUID doesn't have a value id, it doesn't have a function
4084       // summary and we don't need to record any calls to it.
4085       GlobalValue::GUID GUID = EI.first.getGUID();
4086       auto CallValueId = getValueId(GUID);
4087       if (!CallValueId) {
4088         // For SamplePGO, the indirect call targets for local functions will
4089         // have its original name annotated in profile. We try to find the
4090         // corresponding PGOFuncName as the GUID.
4091         GUID = Index.getGUIDFromOriginalID(GUID);
4092         if (GUID == 0)
4093           continue;
4094         CallValueId = getValueId(GUID);
4095         if (!CallValueId)
4096           continue;
4097         // The mapping from OriginalId to GUID may return a GUID
4098         // that corresponds to a static variable. Filter it out here.
4099         // This can happen when
4100         // 1) There is a call to a library function which does not have
4101         // a CallValidId;
4102         // 2) There is a static variable with the  OriginalGUID identical
4103         // to the GUID of the library function in 1);
4104         // When this happens, the logic for SamplePGO kicks in and
4105         // the static variable in 2) will be found, which needs to be
4106         // filtered out.
4107         auto *GVSum = Index.getGlobalValueSummary(GUID, false);
4108         if (GVSum &&
4109             GVSum->getSummaryKind() == GlobalValueSummary::GlobalVarKind)
4110           continue;
4111       }
4112       NameVals.push_back(*CallValueId);
4113       if (HasProfileData)
4114         NameVals.push_back(static_cast<uint8_t>(EI.second.Hotness));
4115     }
4116 
4117     unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
4118     unsigned Code =
4119         (HasProfileData ? bitc::FS_COMBINED_PROFILE : bitc::FS_COMBINED);
4120 
4121     // Emit the finished record.
4122     Stream.EmitRecord(Code, NameVals, FSAbbrev);
4123     NameVals.clear();
4124     MaybeEmitOriginalName(*S);
4125   });
4126 
4127   for (auto *AS : Aliases) {
4128     auto AliasValueId = SummaryToValueIdMap[AS];
4129     assert(AliasValueId);
4130     NameVals.push_back(AliasValueId);
4131     NameVals.push_back(Index.getModuleId(AS->modulePath()));
4132     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
4133     auto AliaseeValueId = SummaryToValueIdMap[&AS->getAliasee()];
4134     assert(AliaseeValueId);
4135     NameVals.push_back(AliaseeValueId);
4136 
4137     // Emit the finished record.
4138     Stream.EmitRecord(bitc::FS_COMBINED_ALIAS, NameVals, FSAliasAbbrev);
4139     NameVals.clear();
4140     MaybeEmitOriginalName(*AS);
4141 
4142     if (auto *FS = dyn_cast<FunctionSummary>(&AS->getAliasee()))
4143       getReferencedTypeIds(FS, ReferencedTypeIds);
4144   }
4145 
4146   if (!Index.cfiFunctionDefs().empty()) {
4147     for (auto &S : Index.cfiFunctionDefs()) {
4148       if (DefOrUseGUIDs.count(
4149               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4150         NameVals.push_back(StrtabBuilder.add(S));
4151         NameVals.push_back(S.size());
4152       }
4153     }
4154     if (!NameVals.empty()) {
4155       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DEFS, NameVals);
4156       NameVals.clear();
4157     }
4158   }
4159 
4160   if (!Index.cfiFunctionDecls().empty()) {
4161     for (auto &S : Index.cfiFunctionDecls()) {
4162       if (DefOrUseGUIDs.count(
4163               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4164         NameVals.push_back(StrtabBuilder.add(S));
4165         NameVals.push_back(S.size());
4166       }
4167     }
4168     if (!NameVals.empty()) {
4169       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DECLS, NameVals);
4170       NameVals.clear();
4171     }
4172   }
4173 
4174   // Walk the GUIDs that were referenced, and write the
4175   // corresponding type id records.
4176   for (auto &T : ReferencedTypeIds) {
4177     auto TidIter = Index.typeIds().equal_range(T);
4178     for (auto It = TidIter.first; It != TidIter.second; ++It) {
4179       writeTypeIdSummaryRecord(NameVals, StrtabBuilder, It->second.first,
4180                                It->second.second);
4181       Stream.EmitRecord(bitc::FS_TYPE_ID, NameVals);
4182       NameVals.clear();
4183     }
4184   }
4185 
4186   Stream.ExitBlock();
4187 }
4188 
4189 /// Create the "IDENTIFICATION_BLOCK_ID" containing a single string with the
4190 /// current llvm version, and a record for the epoch number.
4191 static void writeIdentificationBlock(BitstreamWriter &Stream) {
4192   Stream.EnterSubblock(bitc::IDENTIFICATION_BLOCK_ID, 5);
4193 
4194   // Write the "user readable" string identifying the bitcode producer
4195   auto Abbv = std::make_shared<BitCodeAbbrev>();
4196   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_STRING));
4197   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4198   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
4199   auto StringAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4200   writeStringRecord(Stream, bitc::IDENTIFICATION_CODE_STRING,
4201                     "LLVM" LLVM_VERSION_STRING, StringAbbrev);
4202 
4203   // Write the epoch version
4204   Abbv = std::make_shared<BitCodeAbbrev>();
4205   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_EPOCH));
4206   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
4207   auto EpochAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4208   constexpr std::array<unsigned, 1> Vals = {{bitc::BITCODE_CURRENT_EPOCH}};
4209   Stream.EmitRecord(bitc::IDENTIFICATION_CODE_EPOCH, Vals, EpochAbbrev);
4210   Stream.ExitBlock();
4211 }
4212 
4213 void ModuleBitcodeWriter::writeModuleHash(size_t BlockStartPos) {
4214   // Emit the module's hash.
4215   // MODULE_CODE_HASH: [5*i32]
4216   if (GenerateHash) {
4217     uint32_t Vals[5];
4218     Hasher.update(ArrayRef<uint8_t>((const uint8_t *)&(Buffer)[BlockStartPos],
4219                                     Buffer.size() - BlockStartPos));
4220     StringRef Hash = Hasher.result();
4221     for (int Pos = 0; Pos < 20; Pos += 4) {
4222       Vals[Pos / 4] = support::endian::read32be(Hash.data() + Pos);
4223     }
4224 
4225     // Emit the finished record.
4226     Stream.EmitRecord(bitc::MODULE_CODE_HASH, Vals);
4227 
4228     if (ModHash)
4229       // Save the written hash value.
4230       llvm::copy(Vals, std::begin(*ModHash));
4231   }
4232 }
4233 
4234 void ModuleBitcodeWriter::write() {
4235   writeIdentificationBlock(Stream);
4236 
4237   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4238   size_t BlockStartPos = Buffer.size();
4239 
4240   writeModuleVersion();
4241 
4242   // Emit blockinfo, which defines the standard abbreviations etc.
4243   writeBlockInfo();
4244 
4245   // Emit information describing all of the types in the module.
4246   writeTypeTable();
4247 
4248   // Emit information about attribute groups.
4249   writeAttributeGroupTable();
4250 
4251   // Emit information about parameter attributes.
4252   writeAttributeTable();
4253 
4254   writeComdats();
4255 
4256   // Emit top-level description of module, including target triple, inline asm,
4257   // descriptors for global variables, and function prototype info.
4258   writeModuleInfo();
4259 
4260   // Emit constants.
4261   writeModuleConstants();
4262 
4263   // Emit metadata kind names.
4264   writeModuleMetadataKinds();
4265 
4266   // Emit metadata.
4267   writeModuleMetadata();
4268 
4269   // Emit module-level use-lists.
4270   if (VE.shouldPreserveUseListOrder())
4271     writeUseListBlock(nullptr);
4272 
4273   writeOperandBundleTags();
4274   writeSyncScopeNames();
4275 
4276   // Emit function bodies.
4277   DenseMap<const Function *, uint64_t> FunctionToBitcodeIndex;
4278   for (Module::const_iterator F = M.begin(), E = M.end(); F != E; ++F)
4279     if (!F->isDeclaration())
4280       writeFunction(*F, FunctionToBitcodeIndex);
4281 
4282   // Need to write after the above call to WriteFunction which populates
4283   // the summary information in the index.
4284   if (Index)
4285     writePerModuleGlobalValueSummary();
4286 
4287   writeGlobalValueSymbolTable(FunctionToBitcodeIndex);
4288 
4289   writeModuleHash(BlockStartPos);
4290 
4291   Stream.ExitBlock();
4292 }
4293 
4294 static void writeInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
4295                                uint32_t &Position) {
4296   support::endian::write32le(&Buffer[Position], Value);
4297   Position += 4;
4298 }
4299 
4300 /// If generating a bc file on darwin, we have to emit a
4301 /// header and trailer to make it compatible with the system archiver.  To do
4302 /// this we emit the following header, and then emit a trailer that pads the
4303 /// file out to be a multiple of 16 bytes.
4304 ///
4305 /// struct bc_header {
4306 ///   uint32_t Magic;         // 0x0B17C0DE
4307 ///   uint32_t Version;       // Version, currently always 0.
4308 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
4309 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
4310 ///   uint32_t CPUType;       // CPU specifier.
4311 ///   ... potentially more later ...
4312 /// };
4313 static void emitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
4314                                          const Triple &TT) {
4315   unsigned CPUType = ~0U;
4316 
4317   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
4318   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
4319   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
4320   // specific constants here because they are implicitly part of the Darwin ABI.
4321   enum {
4322     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
4323     DARWIN_CPU_TYPE_X86        = 7,
4324     DARWIN_CPU_TYPE_ARM        = 12,
4325     DARWIN_CPU_TYPE_POWERPC    = 18
4326   };
4327 
4328   Triple::ArchType Arch = TT.getArch();
4329   if (Arch == Triple::x86_64)
4330     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
4331   else if (Arch == Triple::x86)
4332     CPUType = DARWIN_CPU_TYPE_X86;
4333   else if (Arch == Triple::ppc)
4334     CPUType = DARWIN_CPU_TYPE_POWERPC;
4335   else if (Arch == Triple::ppc64)
4336     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
4337   else if (Arch == Triple::arm || Arch == Triple::thumb)
4338     CPUType = DARWIN_CPU_TYPE_ARM;
4339 
4340   // Traditional Bitcode starts after header.
4341   assert(Buffer.size() >= BWH_HeaderSize &&
4342          "Expected header size to be reserved");
4343   unsigned BCOffset = BWH_HeaderSize;
4344   unsigned BCSize = Buffer.size() - BWH_HeaderSize;
4345 
4346   // Write the magic and version.
4347   unsigned Position = 0;
4348   writeInt32ToBuffer(0x0B17C0DE, Buffer, Position);
4349   writeInt32ToBuffer(0, Buffer, Position); // Version.
4350   writeInt32ToBuffer(BCOffset, Buffer, Position);
4351   writeInt32ToBuffer(BCSize, Buffer, Position);
4352   writeInt32ToBuffer(CPUType, Buffer, Position);
4353 
4354   // If the file is not a multiple of 16 bytes, insert dummy padding.
4355   while (Buffer.size() & 15)
4356     Buffer.push_back(0);
4357 }
4358 
4359 /// Helper to write the header common to all bitcode files.
4360 static void writeBitcodeHeader(BitstreamWriter &Stream) {
4361   // Emit the file header.
4362   Stream.Emit((unsigned)'B', 8);
4363   Stream.Emit((unsigned)'C', 8);
4364   Stream.Emit(0x0, 4);
4365   Stream.Emit(0xC, 4);
4366   Stream.Emit(0xE, 4);
4367   Stream.Emit(0xD, 4);
4368 }
4369 
4370 BitcodeWriter::BitcodeWriter(SmallVectorImpl<char> &Buffer)
4371     : Buffer(Buffer), Stream(new BitstreamWriter(Buffer)) {
4372   writeBitcodeHeader(*Stream);
4373 }
4374 
4375 BitcodeWriter::~BitcodeWriter() { assert(WroteStrtab); }
4376 
4377 void BitcodeWriter::writeBlob(unsigned Block, unsigned Record, StringRef Blob) {
4378   Stream->EnterSubblock(Block, 3);
4379 
4380   auto Abbv = std::make_shared<BitCodeAbbrev>();
4381   Abbv->Add(BitCodeAbbrevOp(Record));
4382   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
4383   auto AbbrevNo = Stream->EmitAbbrev(std::move(Abbv));
4384 
4385   Stream->EmitRecordWithBlob(AbbrevNo, ArrayRef<uint64_t>{Record}, Blob);
4386 
4387   Stream->ExitBlock();
4388 }
4389 
4390 void BitcodeWriter::writeSymtab() {
4391   assert(!WroteStrtab && !WroteSymtab);
4392 
4393   // If any module has module-level inline asm, we will require a registered asm
4394   // parser for the target so that we can create an accurate symbol table for
4395   // the module.
4396   for (Module *M : Mods) {
4397     if (M->getModuleInlineAsm().empty())
4398       continue;
4399 
4400     std::string Err;
4401     const Triple TT(M->getTargetTriple());
4402     const Target *T = TargetRegistry::lookupTarget(TT.str(), Err);
4403     if (!T || !T->hasMCAsmParser())
4404       return;
4405   }
4406 
4407   WroteSymtab = true;
4408   SmallVector<char, 0> Symtab;
4409   // The irsymtab::build function may be unable to create a symbol table if the
4410   // module is malformed (e.g. it contains an invalid alias). Writing a symbol
4411   // table is not required for correctness, but we still want to be able to
4412   // write malformed modules to bitcode files, so swallow the error.
4413   if (Error E = irsymtab::build(Mods, Symtab, StrtabBuilder, Alloc)) {
4414     consumeError(std::move(E));
4415     return;
4416   }
4417 
4418   writeBlob(bitc::SYMTAB_BLOCK_ID, bitc::SYMTAB_BLOB,
4419             {Symtab.data(), Symtab.size()});
4420 }
4421 
4422 void BitcodeWriter::writeStrtab() {
4423   assert(!WroteStrtab);
4424 
4425   std::vector<char> Strtab;
4426   StrtabBuilder.finalizeInOrder();
4427   Strtab.resize(StrtabBuilder.getSize());
4428   StrtabBuilder.write((uint8_t *)Strtab.data());
4429 
4430   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB,
4431             {Strtab.data(), Strtab.size()});
4432 
4433   WroteStrtab = true;
4434 }
4435 
4436 void BitcodeWriter::copyStrtab(StringRef Strtab) {
4437   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB, Strtab);
4438   WroteStrtab = true;
4439 }
4440 
4441 void BitcodeWriter::writeModule(const Module &M,
4442                                 bool ShouldPreserveUseListOrder,
4443                                 const ModuleSummaryIndex *Index,
4444                                 bool GenerateHash, ModuleHash *ModHash) {
4445   assert(!WroteStrtab);
4446 
4447   // The Mods vector is used by irsymtab::build, which requires non-const
4448   // Modules in case it needs to materialize metadata. But the bitcode writer
4449   // requires that the module is materialized, so we can cast to non-const here,
4450   // after checking that it is in fact materialized.
4451   assert(M.isMaterialized());
4452   Mods.push_back(const_cast<Module *>(&M));
4453 
4454   ModuleBitcodeWriter ModuleWriter(M, Buffer, StrtabBuilder, *Stream,
4455                                    ShouldPreserveUseListOrder, Index,
4456                                    GenerateHash, ModHash);
4457   ModuleWriter.write();
4458 }
4459 
4460 void BitcodeWriter::writeIndex(
4461     const ModuleSummaryIndex *Index,
4462     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4463   IndexBitcodeWriter IndexWriter(*Stream, StrtabBuilder, *Index,
4464                                  ModuleToSummariesForIndex);
4465   IndexWriter.write();
4466 }
4467 
4468 /// Write the specified module to the specified output stream.
4469 void llvm::WriteBitcodeToFile(const Module &M, raw_ostream &Out,
4470                               bool ShouldPreserveUseListOrder,
4471                               const ModuleSummaryIndex *Index,
4472                               bool GenerateHash, ModuleHash *ModHash) {
4473   SmallVector<char, 0> Buffer;
4474   Buffer.reserve(256*1024);
4475 
4476   // If this is darwin or another generic macho target, reserve space for the
4477   // header.
4478   Triple TT(M.getTargetTriple());
4479   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4480     Buffer.insert(Buffer.begin(), BWH_HeaderSize, 0);
4481 
4482   BitcodeWriter Writer(Buffer);
4483   Writer.writeModule(M, ShouldPreserveUseListOrder, Index, GenerateHash,
4484                      ModHash);
4485   Writer.writeSymtab();
4486   Writer.writeStrtab();
4487 
4488   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4489     emitDarwinBCHeaderAndTrailer(Buffer, TT);
4490 
4491   // Write the generated bitstream to "Out".
4492   Out.write((char*)&Buffer.front(), Buffer.size());
4493 }
4494 
4495 void IndexBitcodeWriter::write() {
4496   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4497 
4498   writeModuleVersion();
4499 
4500   // Write the module paths in the combined index.
4501   writeModStrings();
4502 
4503   // Write the summary combined index records.
4504   writeCombinedGlobalValueSummary();
4505 
4506   Stream.ExitBlock();
4507 }
4508 
4509 // Write the specified module summary index to the given raw output stream,
4510 // where it will be written in a new bitcode block. This is used when
4511 // writing the combined index file for ThinLTO. When writing a subset of the
4512 // index for a distributed backend, provide a \p ModuleToSummariesForIndex map.
4513 void llvm::WriteIndexToFile(
4514     const ModuleSummaryIndex &Index, raw_ostream &Out,
4515     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4516   SmallVector<char, 0> Buffer;
4517   Buffer.reserve(256 * 1024);
4518 
4519   BitcodeWriter Writer(Buffer);
4520   Writer.writeIndex(&Index, ModuleToSummariesForIndex);
4521   Writer.writeStrtab();
4522 
4523   Out.write((char *)&Buffer.front(), Buffer.size());
4524 }
4525 
4526 namespace {
4527 
4528 /// Class to manage the bitcode writing for a thin link bitcode file.
4529 class ThinLinkBitcodeWriter : public ModuleBitcodeWriterBase {
4530   /// ModHash is for use in ThinLTO incremental build, generated while writing
4531   /// the module bitcode file.
4532   const ModuleHash *ModHash;
4533 
4534 public:
4535   ThinLinkBitcodeWriter(const Module &M, StringTableBuilder &StrtabBuilder,
4536                         BitstreamWriter &Stream,
4537                         const ModuleSummaryIndex &Index,
4538                         const ModuleHash &ModHash)
4539       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
4540                                 /*ShouldPreserveUseListOrder=*/false, &Index),
4541         ModHash(&ModHash) {}
4542 
4543   void write();
4544 
4545 private:
4546   void writeSimplifiedModuleInfo();
4547 };
4548 
4549 } // end anonymous namespace
4550 
4551 // This function writes a simpilified module info for thin link bitcode file.
4552 // It only contains the source file name along with the name(the offset and
4553 // size in strtab) and linkage for global values. For the global value info
4554 // entry, in order to keep linkage at offset 5, there are three zeros used
4555 // as padding.
4556 void ThinLinkBitcodeWriter::writeSimplifiedModuleInfo() {
4557   SmallVector<unsigned, 64> Vals;
4558   // Emit the module's source file name.
4559   {
4560     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
4561     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
4562     if (Bits == SE_Char6)
4563       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
4564     else if (Bits == SE_Fixed7)
4565       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
4566 
4567     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
4568     auto Abbv = std::make_shared<BitCodeAbbrev>();
4569     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
4570     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4571     Abbv->Add(AbbrevOpToUse);
4572     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4573 
4574     for (const auto P : M.getSourceFileName())
4575       Vals.push_back((unsigned char)P);
4576 
4577     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
4578     Vals.clear();
4579   }
4580 
4581   // Emit the global variable information.
4582   for (const GlobalVariable &GV : M.globals()) {
4583     // GLOBALVAR: [strtab offset, strtab size, 0, 0, 0, linkage]
4584     Vals.push_back(StrtabBuilder.add(GV.getName()));
4585     Vals.push_back(GV.getName().size());
4586     Vals.push_back(0);
4587     Vals.push_back(0);
4588     Vals.push_back(0);
4589     Vals.push_back(getEncodedLinkage(GV));
4590 
4591     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals);
4592     Vals.clear();
4593   }
4594 
4595   // Emit the function proto information.
4596   for (const Function &F : M) {
4597     // FUNCTION:  [strtab offset, strtab size, 0, 0, 0, linkage]
4598     Vals.push_back(StrtabBuilder.add(F.getName()));
4599     Vals.push_back(F.getName().size());
4600     Vals.push_back(0);
4601     Vals.push_back(0);
4602     Vals.push_back(0);
4603     Vals.push_back(getEncodedLinkage(F));
4604 
4605     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals);
4606     Vals.clear();
4607   }
4608 
4609   // Emit the alias information.
4610   for (const GlobalAlias &A : M.aliases()) {
4611     // ALIAS: [strtab offset, strtab size, 0, 0, 0, linkage]
4612     Vals.push_back(StrtabBuilder.add(A.getName()));
4613     Vals.push_back(A.getName().size());
4614     Vals.push_back(0);
4615     Vals.push_back(0);
4616     Vals.push_back(0);
4617     Vals.push_back(getEncodedLinkage(A));
4618 
4619     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals);
4620     Vals.clear();
4621   }
4622 
4623   // Emit the ifunc information.
4624   for (const GlobalIFunc &I : M.ifuncs()) {
4625     // IFUNC: [strtab offset, strtab size, 0, 0, 0, linkage]
4626     Vals.push_back(StrtabBuilder.add(I.getName()));
4627     Vals.push_back(I.getName().size());
4628     Vals.push_back(0);
4629     Vals.push_back(0);
4630     Vals.push_back(0);
4631     Vals.push_back(getEncodedLinkage(I));
4632 
4633     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
4634     Vals.clear();
4635   }
4636 }
4637 
4638 void ThinLinkBitcodeWriter::write() {
4639   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4640 
4641   writeModuleVersion();
4642 
4643   writeSimplifiedModuleInfo();
4644 
4645   writePerModuleGlobalValueSummary();
4646 
4647   // Write module hash.
4648   Stream.EmitRecord(bitc::MODULE_CODE_HASH, ArrayRef<uint32_t>(*ModHash));
4649 
4650   Stream.ExitBlock();
4651 }
4652 
4653 void BitcodeWriter::writeThinLinkBitcode(const Module &M,
4654                                          const ModuleSummaryIndex &Index,
4655                                          const ModuleHash &ModHash) {
4656   assert(!WroteStrtab);
4657 
4658   // The Mods vector is used by irsymtab::build, which requires non-const
4659   // Modules in case it needs to materialize metadata. But the bitcode writer
4660   // requires that the module is materialized, so we can cast to non-const here,
4661   // after checking that it is in fact materialized.
4662   assert(M.isMaterialized());
4663   Mods.push_back(const_cast<Module *>(&M));
4664 
4665   ThinLinkBitcodeWriter ThinLinkWriter(M, StrtabBuilder, *Stream, Index,
4666                                        ModHash);
4667   ThinLinkWriter.write();
4668 }
4669 
4670 // Write the specified thin link bitcode file to the given raw output stream,
4671 // where it will be written in a new bitcode block. This is used when
4672 // writing the per-module index file for ThinLTO.
4673 void llvm::WriteThinLinkBitcodeToFile(const Module &M, raw_ostream &Out,
4674                                       const ModuleSummaryIndex &Index,
4675                                       const ModuleHash &ModHash) {
4676   SmallVector<char, 0> Buffer;
4677   Buffer.reserve(256 * 1024);
4678 
4679   BitcodeWriter Writer(Buffer);
4680   Writer.writeThinLinkBitcode(M, Index, ModHash);
4681   Writer.writeSymtab();
4682   Writer.writeStrtab();
4683 
4684   Out.write((char *)&Buffer.front(), Buffer.size());
4685 }
4686 
4687 static const char *getSectionNameForBitcode(const Triple &T) {
4688   switch (T.getObjectFormat()) {
4689   case Triple::MachO:
4690     return "__LLVM,__bitcode";
4691   case Triple::COFF:
4692   case Triple::ELF:
4693   case Triple::Wasm:
4694   case Triple::UnknownObjectFormat:
4695     return ".llvmbc";
4696   case Triple::XCOFF:
4697     llvm_unreachable("XCOFF is not yet implemented");
4698     break;
4699   }
4700   llvm_unreachable("Unimplemented ObjectFormatType");
4701 }
4702 
4703 static const char *getSectionNameForCommandline(const Triple &T) {
4704   switch (T.getObjectFormat()) {
4705   case Triple::MachO:
4706     return "__LLVM,__cmdline";
4707   case Triple::COFF:
4708   case Triple::ELF:
4709   case Triple::Wasm:
4710   case Triple::UnknownObjectFormat:
4711     return ".llvmcmd";
4712   case Triple::XCOFF:
4713     llvm_unreachable("XCOFF is not yet implemented");
4714     break;
4715   }
4716   llvm_unreachable("Unimplemented ObjectFormatType");
4717 }
4718 
4719 void llvm::EmbedBitcodeInModule(llvm::Module &M, llvm::MemoryBufferRef Buf,
4720                                 bool EmbedBitcode, bool EmbedMarker,
4721                                 const std::vector<uint8_t> *CmdArgs) {
4722   // Save llvm.compiler.used and remove it.
4723   SmallVector<Constant *, 2> UsedArray;
4724   SmallPtrSet<GlobalValue *, 4> UsedGlobals;
4725   Type *UsedElementType = Type::getInt8Ty(M.getContext())->getPointerTo(0);
4726   GlobalVariable *Used = collectUsedGlobalVariables(M, UsedGlobals, true);
4727   for (auto *GV : UsedGlobals) {
4728     if (GV->getName() != "llvm.embedded.module" &&
4729         GV->getName() != "llvm.cmdline")
4730       UsedArray.push_back(
4731           ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
4732   }
4733   if (Used)
4734     Used->eraseFromParent();
4735 
4736   // Embed the bitcode for the llvm module.
4737   std::string Data;
4738   ArrayRef<uint8_t> ModuleData;
4739   Triple T(M.getTargetTriple());
4740   // Create a constant that contains the bitcode.
4741   // In case of embedding a marker, ignore the input Buf and use the empty
4742   // ArrayRef. It is also legal to create a bitcode marker even Buf is empty.
4743   if (EmbedBitcode) {
4744     if (!isBitcode((const unsigned char *)Buf.getBufferStart(),
4745                    (const unsigned char *)Buf.getBufferEnd())) {
4746       // If the input is LLVM Assembly, bitcode is produced by serializing
4747       // the module. Use-lists order need to be preserved in this case.
4748       llvm::raw_string_ostream OS(Data);
4749       llvm::WriteBitcodeToFile(M, OS, /* ShouldPreserveUseListOrder */ true);
4750       ModuleData =
4751           ArrayRef<uint8_t>((const uint8_t *)OS.str().data(), OS.str().size());
4752     } else
4753       // If the input is LLVM bitcode, write the input byte stream directly.
4754       ModuleData = ArrayRef<uint8_t>((const uint8_t *)Buf.getBufferStart(),
4755                                      Buf.getBufferSize());
4756   }
4757   llvm::Constant *ModuleConstant =
4758       llvm::ConstantDataArray::get(M.getContext(), ModuleData);
4759   llvm::GlobalVariable *GV = new llvm::GlobalVariable(
4760       M, ModuleConstant->getType(), true, llvm::GlobalValue::PrivateLinkage,
4761       ModuleConstant);
4762   GV->setSection(getSectionNameForBitcode(T));
4763   UsedArray.push_back(
4764       ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
4765   if (llvm::GlobalVariable *Old =
4766           M.getGlobalVariable("llvm.embedded.module", true)) {
4767     assert(Old->hasOneUse() &&
4768            "llvm.embedded.module can only be used once in llvm.compiler.used");
4769     GV->takeName(Old);
4770     Old->eraseFromParent();
4771   } else {
4772     GV->setName("llvm.embedded.module");
4773   }
4774 
4775   // Skip if only bitcode needs to be embedded.
4776   if (EmbedMarker) {
4777     // Embed command-line options.
4778     ArrayRef<uint8_t> CmdData(const_cast<uint8_t *>(CmdArgs->data()),
4779                               CmdArgs->size());
4780     llvm::Constant *CmdConstant =
4781         llvm::ConstantDataArray::get(M.getContext(), CmdData);
4782     GV = new llvm::GlobalVariable(M, CmdConstant->getType(), true,
4783                                   llvm::GlobalValue::PrivateLinkage,
4784                                   CmdConstant);
4785     GV->setSection(getSectionNameForCommandline(T));
4786     UsedArray.push_back(
4787         ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
4788     if (llvm::GlobalVariable *Old = M.getGlobalVariable("llvm.cmdline", true)) {
4789       assert(Old->hasOneUse() &&
4790              "llvm.cmdline can only be used once in llvm.compiler.used");
4791       GV->takeName(Old);
4792       Old->eraseFromParent();
4793     } else {
4794       GV->setName("llvm.cmdline");
4795     }
4796   }
4797 
4798   if (UsedArray.empty())
4799     return;
4800 
4801   // Recreate llvm.compiler.used.
4802   ArrayType *ATy = ArrayType::get(UsedElementType, UsedArray.size());
4803   auto *NewUsed = new GlobalVariable(
4804       M, ATy, false, llvm::GlobalValue::AppendingLinkage,
4805       llvm::ConstantArray::get(ATy, UsedArray), "llvm.compiler.used");
4806   NewUsed->setSection("llvm.metadata");
4807 }
4808