xref: /llvm-project/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp (revision 1bebc31c617d1a0773f1d561f02dd17c5e83b23b)
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/BitcodeCommon.h"
28 #include "llvm/Bitcode/BitcodeReader.h"
29 #include "llvm/Bitcode/LLVMBitCodes.h"
30 #include "llvm/Bitstream/BitCodes.h"
31 #include "llvm/Bitstream/BitstreamWriter.h"
32 #include "llvm/Config/llvm-config.h"
33 #include "llvm/IR/Attributes.h"
34 #include "llvm/IR/BasicBlock.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 static cl::opt<uint32_t> FlushThreshold(
90     "bitcode-flush-threshold", cl::Hidden, cl::init(512),
91     cl::desc("The threshold (unit M) for flushing LLVM bitcode."));
92 
93 static cl::opt<bool> WriteRelBFToSummary(
94     "write-relbf-to-summary", cl::Hidden, cl::init(false),
95     cl::desc("Write relative block frequency to function summary "));
96 
97 extern FunctionSummary::ForceSummaryHotnessType ForceSummaryEdgesCold;
98 
99 namespace {
100 
101 /// These are manifest constants used by the bitcode writer. They do not need to
102 /// be kept in sync with the reader, but need to be consistent within this file.
103 enum {
104   // VALUE_SYMTAB_BLOCK abbrev id's.
105   VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
106   VST_ENTRY_7_ABBREV,
107   VST_ENTRY_6_ABBREV,
108   VST_BBENTRY_6_ABBREV,
109 
110   // CONSTANTS_BLOCK abbrev id's.
111   CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
112   CONSTANTS_INTEGER_ABBREV,
113   CONSTANTS_CE_CAST_Abbrev,
114   CONSTANTS_NULL_Abbrev,
115 
116   // FUNCTION_BLOCK abbrev id's.
117   FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
118   FUNCTION_INST_UNOP_ABBREV,
119   FUNCTION_INST_UNOP_FLAGS_ABBREV,
120   FUNCTION_INST_BINOP_ABBREV,
121   FUNCTION_INST_BINOP_FLAGS_ABBREV,
122   FUNCTION_INST_CAST_ABBREV,
123   FUNCTION_INST_RET_VOID_ABBREV,
124   FUNCTION_INST_RET_VAL_ABBREV,
125   FUNCTION_INST_UNREACHABLE_ABBREV,
126   FUNCTION_INST_GEP_ABBREV,
127 };
128 
129 /// Abstract class to manage the bitcode writing, subclassed for each bitcode
130 /// file type.
131 class BitcodeWriterBase {
132 protected:
133   /// The stream created and owned by the client.
134   BitstreamWriter &Stream;
135 
136   StringTableBuilder &StrtabBuilder;
137 
138 public:
139   /// Constructs a BitcodeWriterBase object that writes to the provided
140   /// \p Stream.
141   BitcodeWriterBase(BitstreamWriter &Stream, StringTableBuilder &StrtabBuilder)
142       : Stream(Stream), StrtabBuilder(StrtabBuilder) {}
143 
144 protected:
145   void writeModuleVersion();
146 };
147 
148 void BitcodeWriterBase::writeModuleVersion() {
149   // VERSION: [version#]
150   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, ArrayRef<uint64_t>{2});
151 }
152 
153 /// Base class to manage the module bitcode writing, currently subclassed for
154 /// ModuleBitcodeWriter and ThinLinkBitcodeWriter.
155 class ModuleBitcodeWriterBase : public BitcodeWriterBase {
156 protected:
157   /// The Module to write to bitcode.
158   const Module &M;
159 
160   /// Enumerates ids for all values in the module.
161   ValueEnumerator VE;
162 
163   /// Optional per-module index to write for ThinLTO.
164   const ModuleSummaryIndex *Index;
165 
166   /// Map that holds the correspondence between GUIDs in the summary index,
167   /// that came from indirect call profiles, and a value id generated by this
168   /// class to use in the VST and summary block records.
169   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
170 
171   /// Tracks the last value id recorded in the GUIDToValueMap.
172   unsigned GlobalValueId;
173 
174   /// Saves the offset of the VSTOffset record that must eventually be
175   /// backpatched with the offset of the actual VST.
176   uint64_t VSTOffsetPlaceholder = 0;
177 
178 public:
179   /// Constructs a ModuleBitcodeWriterBase object for the given Module,
180   /// writing to the provided \p Buffer.
181   ModuleBitcodeWriterBase(const Module &M, StringTableBuilder &StrtabBuilder,
182                           BitstreamWriter &Stream,
183                           bool ShouldPreserveUseListOrder,
184                           const ModuleSummaryIndex *Index)
185       : BitcodeWriterBase(Stream, StrtabBuilder), M(M),
186         VE(M, ShouldPreserveUseListOrder), Index(Index) {
187     // Assign ValueIds to any callee values in the index that came from
188     // indirect call profiles and were recorded as a GUID not a Value*
189     // (which would have been assigned an ID by the ValueEnumerator).
190     // The starting ValueId is just after the number of values in the
191     // ValueEnumerator, so that they can be emitted in the VST.
192     GlobalValueId = VE.getValues().size();
193     if (!Index)
194       return;
195     for (const auto &GUIDSummaryLists : *Index)
196       // Examine all summaries for this GUID.
197       for (auto &Summary : GUIDSummaryLists.second.SummaryList)
198         if (auto FS = dyn_cast<FunctionSummary>(Summary.get()))
199           // For each call in the function summary, see if the call
200           // is to a GUID (which means it is for an indirect call,
201           // otherwise we would have a Value for it). If so, synthesize
202           // a value id.
203           for (auto &CallEdge : FS->calls())
204             if (!CallEdge.first.haveGVs() || !CallEdge.first.getValue())
205               assignValueId(CallEdge.first.getGUID());
206   }
207 
208 protected:
209   void writePerModuleGlobalValueSummary();
210 
211 private:
212   void writePerModuleFunctionSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
213                                            GlobalValueSummary *Summary,
214                                            unsigned ValueID,
215                                            unsigned FSCallsAbbrev,
216                                            unsigned FSCallsProfileAbbrev,
217                                            const Function &F);
218   void writeModuleLevelReferences(const GlobalVariable &V,
219                                   SmallVector<uint64_t, 64> &NameVals,
220                                   unsigned FSModRefsAbbrev,
221                                   unsigned FSModVTableRefsAbbrev);
222 
223   void assignValueId(GlobalValue::GUID ValGUID) {
224     GUIDToValueIdMap[ValGUID] = ++GlobalValueId;
225   }
226 
227   unsigned getValueId(GlobalValue::GUID ValGUID) {
228     const auto &VMI = GUIDToValueIdMap.find(ValGUID);
229     // Expect that any GUID value had a value Id assigned by an
230     // earlier call to assignValueId.
231     assert(VMI != GUIDToValueIdMap.end() &&
232            "GUID does not have assigned value Id");
233     return VMI->second;
234   }
235 
236   // Helper to get the valueId for the type of value recorded in VI.
237   unsigned getValueId(ValueInfo VI) {
238     if (!VI.haveGVs() || !VI.getValue())
239       return getValueId(VI.getGUID());
240     return VE.getValueID(VI.getValue());
241   }
242 
243   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
244 };
245 
246 /// Class to manage the bitcode writing for a module.
247 class ModuleBitcodeWriter : public ModuleBitcodeWriterBase {
248   /// Pointer to the buffer allocated by caller for bitcode writing.
249   const SmallVectorImpl<char> &Buffer;
250 
251   /// True if a module hash record should be written.
252   bool GenerateHash;
253 
254   /// If non-null, when GenerateHash is true, the resulting hash is written
255   /// into ModHash.
256   ModuleHash *ModHash;
257 
258   SHA1 Hasher;
259 
260   /// The start bit of the identification block.
261   uint64_t BitcodeStartBit;
262 
263 public:
264   /// Constructs a ModuleBitcodeWriter object for the given Module,
265   /// writing to the provided \p Buffer.
266   ModuleBitcodeWriter(const Module &M, SmallVectorImpl<char> &Buffer,
267                       StringTableBuilder &StrtabBuilder,
268                       BitstreamWriter &Stream, bool ShouldPreserveUseListOrder,
269                       const ModuleSummaryIndex *Index, bool GenerateHash,
270                       ModuleHash *ModHash = nullptr)
271       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
272                                 ShouldPreserveUseListOrder, Index),
273         Buffer(Buffer), GenerateHash(GenerateHash), ModHash(ModHash),
274         BitcodeStartBit(Stream.GetCurrentBitNo()) {}
275 
276   /// Emit the current module to the bitstream.
277   void write();
278 
279 private:
280   uint64_t bitcodeStartBit() { return BitcodeStartBit; }
281 
282   size_t addToStrtab(StringRef Str);
283 
284   void writeAttributeGroupTable();
285   void writeAttributeTable();
286   void writeTypeTable();
287   void writeComdats();
288   void writeValueSymbolTableForwardDecl();
289   void writeModuleInfo();
290   void writeValueAsMetadata(const ValueAsMetadata *MD,
291                             SmallVectorImpl<uint64_t> &Record);
292   void writeMDTuple(const MDTuple *N, SmallVectorImpl<uint64_t> &Record,
293                     unsigned Abbrev);
294   unsigned createDILocationAbbrev();
295   void writeDILocation(const DILocation *N, SmallVectorImpl<uint64_t> &Record,
296                        unsigned &Abbrev);
297   unsigned createGenericDINodeAbbrev();
298   void writeGenericDINode(const GenericDINode *N,
299                           SmallVectorImpl<uint64_t> &Record, unsigned &Abbrev);
300   void writeDISubrange(const DISubrange *N, SmallVectorImpl<uint64_t> &Record,
301                        unsigned Abbrev);
302   void writeDIGenericSubrange(const DIGenericSubrange *N,
303                               SmallVectorImpl<uint64_t> &Record,
304                               unsigned Abbrev);
305   void writeDIEnumerator(const DIEnumerator *N,
306                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
307   void writeDIBasicType(const DIBasicType *N, SmallVectorImpl<uint64_t> &Record,
308                         unsigned Abbrev);
309   void writeDIStringType(const DIStringType *N,
310                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
311   void writeDIDerivedType(const DIDerivedType *N,
312                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
313   void writeDICompositeType(const DICompositeType *N,
314                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
315   void writeDISubroutineType(const DISubroutineType *N,
316                              SmallVectorImpl<uint64_t> &Record,
317                              unsigned Abbrev);
318   void writeDIFile(const DIFile *N, SmallVectorImpl<uint64_t> &Record,
319                    unsigned Abbrev);
320   void writeDICompileUnit(const DICompileUnit *N,
321                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
322   void writeDISubprogram(const DISubprogram *N,
323                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
324   void writeDILexicalBlock(const DILexicalBlock *N,
325                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
326   void writeDILexicalBlockFile(const DILexicalBlockFile *N,
327                                SmallVectorImpl<uint64_t> &Record,
328                                unsigned Abbrev);
329   void writeDICommonBlock(const DICommonBlock *N,
330                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
331   void writeDINamespace(const DINamespace *N, SmallVectorImpl<uint64_t> &Record,
332                         unsigned Abbrev);
333   void writeDIMacro(const DIMacro *N, SmallVectorImpl<uint64_t> &Record,
334                     unsigned Abbrev);
335   void writeDIMacroFile(const DIMacroFile *N, SmallVectorImpl<uint64_t> &Record,
336                         unsigned Abbrev);
337   void writeDIArgList(const DIArgList *N, SmallVectorImpl<uint64_t> &Record,
338                       unsigned Abbrev);
339   void writeDIModule(const DIModule *N, SmallVectorImpl<uint64_t> &Record,
340                      unsigned Abbrev);
341   void writeDITemplateTypeParameter(const DITemplateTypeParameter *N,
342                                     SmallVectorImpl<uint64_t> &Record,
343                                     unsigned Abbrev);
344   void writeDITemplateValueParameter(const DITemplateValueParameter *N,
345                                      SmallVectorImpl<uint64_t> &Record,
346                                      unsigned Abbrev);
347   void writeDIGlobalVariable(const DIGlobalVariable *N,
348                              SmallVectorImpl<uint64_t> &Record,
349                              unsigned Abbrev);
350   void writeDILocalVariable(const DILocalVariable *N,
351                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
352   void writeDILabel(const DILabel *N,
353                     SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
354   void writeDIExpression(const DIExpression *N,
355                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
356   void writeDIGlobalVariableExpression(const DIGlobalVariableExpression *N,
357                                        SmallVectorImpl<uint64_t> &Record,
358                                        unsigned Abbrev);
359   void writeDIObjCProperty(const DIObjCProperty *N,
360                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
361   void writeDIImportedEntity(const DIImportedEntity *N,
362                              SmallVectorImpl<uint64_t> &Record,
363                              unsigned Abbrev);
364   unsigned createNamedMetadataAbbrev();
365   void writeNamedMetadata(SmallVectorImpl<uint64_t> &Record);
366   unsigned createMetadataStringsAbbrev();
367   void writeMetadataStrings(ArrayRef<const Metadata *> Strings,
368                             SmallVectorImpl<uint64_t> &Record);
369   void writeMetadataRecords(ArrayRef<const Metadata *> MDs,
370                             SmallVectorImpl<uint64_t> &Record,
371                             std::vector<unsigned> *MDAbbrevs = nullptr,
372                             std::vector<uint64_t> *IndexPos = nullptr);
373   void writeModuleMetadata();
374   void writeFunctionMetadata(const Function &F);
375   void writeFunctionMetadataAttachment(const Function &F);
376   void pushGlobalMetadataAttachment(SmallVectorImpl<uint64_t> &Record,
377                                     const GlobalObject &GO);
378   void writeModuleMetadataKinds();
379   void writeOperandBundleTags();
380   void writeSyncScopeNames();
381   void writeConstants(unsigned FirstVal, unsigned LastVal, bool isGlobal);
382   void writeModuleConstants();
383   bool pushValueAndType(const Value *V, unsigned InstID,
384                         SmallVectorImpl<unsigned> &Vals);
385   void writeOperandBundles(const CallBase &CB, unsigned InstID);
386   void pushValue(const Value *V, unsigned InstID,
387                  SmallVectorImpl<unsigned> &Vals);
388   void pushValueSigned(const Value *V, unsigned InstID,
389                        SmallVectorImpl<uint64_t> &Vals);
390   void writeInstruction(const Instruction &I, unsigned InstID,
391                         SmallVectorImpl<unsigned> &Vals);
392   void writeFunctionLevelValueSymbolTable(const ValueSymbolTable &VST);
393   void writeGlobalValueSymbolTable(
394       DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
395   void writeUseList(UseListOrder &&Order);
396   void writeUseListBlock(const Function *F);
397   void
398   writeFunction(const Function &F,
399                 DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
400   void writeBlockInfo();
401   void writeModuleHash(size_t BlockStartPos);
402 
403   unsigned getEncodedSyncScopeID(SyncScope::ID SSID) {
404     return unsigned(SSID);
405   }
406 
407   unsigned getEncodedAlign(MaybeAlign Alignment) { return encode(Alignment); }
408 };
409 
410 /// Class to manage the bitcode writing for a combined index.
411 class IndexBitcodeWriter : public BitcodeWriterBase {
412   /// The combined index to write to bitcode.
413   const ModuleSummaryIndex &Index;
414 
415   /// When writing a subset of the index for distributed backends, client
416   /// provides a map of modules to the corresponding GUIDs/summaries to write.
417   const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex;
418 
419   /// Map that holds the correspondence between the GUID used in the combined
420   /// index and a value id generated by this class to use in references.
421   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
422 
423   /// Tracks the last value id recorded in the GUIDToValueMap.
424   unsigned GlobalValueId = 0;
425 
426 public:
427   /// Constructs a IndexBitcodeWriter object for the given combined index,
428   /// writing to the provided \p Buffer. When writing a subset of the index
429   /// for a distributed backend, provide a \p ModuleToSummariesForIndex map.
430   IndexBitcodeWriter(BitstreamWriter &Stream, StringTableBuilder &StrtabBuilder,
431                      const ModuleSummaryIndex &Index,
432                      const std::map<std::string, GVSummaryMapTy>
433                          *ModuleToSummariesForIndex = nullptr)
434       : BitcodeWriterBase(Stream, StrtabBuilder), Index(Index),
435         ModuleToSummariesForIndex(ModuleToSummariesForIndex) {
436     // Assign unique value ids to all summaries to be written, for use
437     // in writing out the call graph edges. Save the mapping from GUID
438     // to the new global value id to use when writing those edges, which
439     // are currently saved in the index in terms of GUID.
440     forEachSummary([&](GVInfo I, bool) {
441       GUIDToValueIdMap[I.first] = ++GlobalValueId;
442     });
443   }
444 
445   /// The below iterator returns the GUID and associated summary.
446   using GVInfo = std::pair<GlobalValue::GUID, GlobalValueSummary *>;
447 
448   /// Calls the callback for each value GUID and summary to be written to
449   /// bitcode. This hides the details of whether they are being pulled from the
450   /// entire index or just those in a provided ModuleToSummariesForIndex map.
451   template<typename Functor>
452   void forEachSummary(Functor Callback) {
453     if (ModuleToSummariesForIndex) {
454       for (auto &M : *ModuleToSummariesForIndex)
455         for (auto &Summary : M.second) {
456           Callback(Summary, false);
457           // Ensure aliasee is handled, e.g. for assigning a valueId,
458           // even if we are not importing the aliasee directly (the
459           // imported alias will contain a copy of aliasee).
460           if (auto *AS = dyn_cast<AliasSummary>(Summary.getSecond()))
461             Callback({AS->getAliaseeGUID(), &AS->getAliasee()}, true);
462         }
463     } else {
464       for (auto &Summaries : Index)
465         for (auto &Summary : Summaries.second.SummaryList)
466           Callback({Summaries.first, Summary.get()}, false);
467     }
468   }
469 
470   /// Calls the callback for each entry in the modulePaths StringMap that
471   /// should be written to the module path string table. This hides the details
472   /// of whether they are being pulled from the entire index or just those in a
473   /// provided ModuleToSummariesForIndex map.
474   template <typename Functor> void forEachModule(Functor Callback) {
475     if (ModuleToSummariesForIndex) {
476       for (const auto &M : *ModuleToSummariesForIndex) {
477         const auto &MPI = Index.modulePaths().find(M.first);
478         if (MPI == Index.modulePaths().end()) {
479           // This should only happen if the bitcode file was empty, in which
480           // case we shouldn't be importing (the ModuleToSummariesForIndex
481           // would only include the module we are writing and index for).
482           assert(ModuleToSummariesForIndex->size() == 1);
483           continue;
484         }
485         Callback(*MPI);
486       }
487     } else {
488       for (const auto &MPSE : Index.modulePaths())
489         Callback(MPSE);
490     }
491   }
492 
493   /// Main entry point for writing a combined index to bitcode.
494   void write();
495 
496 private:
497   void writeModStrings();
498   void writeCombinedGlobalValueSummary();
499 
500   Optional<unsigned> getValueId(GlobalValue::GUID ValGUID) {
501     auto VMI = GUIDToValueIdMap.find(ValGUID);
502     if (VMI == GUIDToValueIdMap.end())
503       return None;
504     return VMI->second;
505   }
506 
507   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
508 };
509 
510 } // end anonymous namespace
511 
512 static unsigned getEncodedCastOpcode(unsigned Opcode) {
513   switch (Opcode) {
514   default: llvm_unreachable("Unknown cast instruction!");
515   case Instruction::Trunc   : return bitc::CAST_TRUNC;
516   case Instruction::ZExt    : return bitc::CAST_ZEXT;
517   case Instruction::SExt    : return bitc::CAST_SEXT;
518   case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
519   case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
520   case Instruction::UIToFP  : return bitc::CAST_UITOFP;
521   case Instruction::SIToFP  : return bitc::CAST_SITOFP;
522   case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
523   case Instruction::FPExt   : return bitc::CAST_FPEXT;
524   case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
525   case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
526   case Instruction::BitCast : return bitc::CAST_BITCAST;
527   case Instruction::AddrSpaceCast: return bitc::CAST_ADDRSPACECAST;
528   }
529 }
530 
531 static unsigned getEncodedUnaryOpcode(unsigned Opcode) {
532   switch (Opcode) {
533   default: llvm_unreachable("Unknown binary instruction!");
534   case Instruction::FNeg: return bitc::UNOP_FNEG;
535   }
536 }
537 
538 static unsigned getEncodedBinaryOpcode(unsigned Opcode) {
539   switch (Opcode) {
540   default: llvm_unreachable("Unknown binary instruction!");
541   case Instruction::Add:
542   case Instruction::FAdd: return bitc::BINOP_ADD;
543   case Instruction::Sub:
544   case Instruction::FSub: return bitc::BINOP_SUB;
545   case Instruction::Mul:
546   case Instruction::FMul: return bitc::BINOP_MUL;
547   case Instruction::UDiv: return bitc::BINOP_UDIV;
548   case Instruction::FDiv:
549   case Instruction::SDiv: return bitc::BINOP_SDIV;
550   case Instruction::URem: return bitc::BINOP_UREM;
551   case Instruction::FRem:
552   case Instruction::SRem: return bitc::BINOP_SREM;
553   case Instruction::Shl:  return bitc::BINOP_SHL;
554   case Instruction::LShr: return bitc::BINOP_LSHR;
555   case Instruction::AShr: return bitc::BINOP_ASHR;
556   case Instruction::And:  return bitc::BINOP_AND;
557   case Instruction::Or:   return bitc::BINOP_OR;
558   case Instruction::Xor:  return bitc::BINOP_XOR;
559   }
560 }
561 
562 static unsigned getEncodedRMWOperation(AtomicRMWInst::BinOp Op) {
563   switch (Op) {
564   default: llvm_unreachable("Unknown RMW operation!");
565   case AtomicRMWInst::Xchg: return bitc::RMW_XCHG;
566   case AtomicRMWInst::Add: return bitc::RMW_ADD;
567   case AtomicRMWInst::Sub: return bitc::RMW_SUB;
568   case AtomicRMWInst::And: return bitc::RMW_AND;
569   case AtomicRMWInst::Nand: return bitc::RMW_NAND;
570   case AtomicRMWInst::Or: return bitc::RMW_OR;
571   case AtomicRMWInst::Xor: return bitc::RMW_XOR;
572   case AtomicRMWInst::Max: return bitc::RMW_MAX;
573   case AtomicRMWInst::Min: return bitc::RMW_MIN;
574   case AtomicRMWInst::UMax: return bitc::RMW_UMAX;
575   case AtomicRMWInst::UMin: return bitc::RMW_UMIN;
576   case AtomicRMWInst::FAdd: return bitc::RMW_FADD;
577   case AtomicRMWInst::FSub: return bitc::RMW_FSUB;
578   }
579 }
580 
581 static unsigned getEncodedOrdering(AtomicOrdering Ordering) {
582   switch (Ordering) {
583   case AtomicOrdering::NotAtomic: return bitc::ORDERING_NOTATOMIC;
584   case AtomicOrdering::Unordered: return bitc::ORDERING_UNORDERED;
585   case AtomicOrdering::Monotonic: return bitc::ORDERING_MONOTONIC;
586   case AtomicOrdering::Acquire: return bitc::ORDERING_ACQUIRE;
587   case AtomicOrdering::Release: return bitc::ORDERING_RELEASE;
588   case AtomicOrdering::AcquireRelease: return bitc::ORDERING_ACQREL;
589   case AtomicOrdering::SequentiallyConsistent: return bitc::ORDERING_SEQCST;
590   }
591   llvm_unreachable("Invalid ordering");
592 }
593 
594 static void writeStringRecord(BitstreamWriter &Stream, unsigned Code,
595                               StringRef Str, unsigned AbbrevToUse) {
596   SmallVector<unsigned, 64> Vals;
597 
598   // Code: [strchar x N]
599   for (unsigned i = 0, e = Str.size(); i != e; ++i) {
600     if (AbbrevToUse && !BitCodeAbbrevOp::isChar6(Str[i]))
601       AbbrevToUse = 0;
602     Vals.push_back(Str[i]);
603   }
604 
605   // Emit the finished record.
606   Stream.EmitRecord(Code, Vals, AbbrevToUse);
607 }
608 
609 static uint64_t getAttrKindEncoding(Attribute::AttrKind Kind) {
610   switch (Kind) {
611   case Attribute::Alignment:
612     return bitc::ATTR_KIND_ALIGNMENT;
613   case Attribute::AllocSize:
614     return bitc::ATTR_KIND_ALLOC_SIZE;
615   case Attribute::AlwaysInline:
616     return bitc::ATTR_KIND_ALWAYS_INLINE;
617   case Attribute::ArgMemOnly:
618     return bitc::ATTR_KIND_ARGMEMONLY;
619   case Attribute::Builtin:
620     return bitc::ATTR_KIND_BUILTIN;
621   case Attribute::ByVal:
622     return bitc::ATTR_KIND_BY_VAL;
623   case Attribute::Convergent:
624     return bitc::ATTR_KIND_CONVERGENT;
625   case Attribute::InAlloca:
626     return bitc::ATTR_KIND_IN_ALLOCA;
627   case Attribute::Cold:
628     return bitc::ATTR_KIND_COLD;
629   case Attribute::DisableSanitizerInstrumentation:
630     return bitc::ATTR_KIND_DISABLE_SANITIZER_INSTRUMENTATION;
631   case Attribute::Hot:
632     return bitc::ATTR_KIND_HOT;
633   case Attribute::ElementType:
634     return bitc::ATTR_KIND_ELEMENTTYPE;
635   case Attribute::InaccessibleMemOnly:
636     return bitc::ATTR_KIND_INACCESSIBLEMEM_ONLY;
637   case Attribute::InaccessibleMemOrArgMemOnly:
638     return bitc::ATTR_KIND_INACCESSIBLEMEM_OR_ARGMEMONLY;
639   case Attribute::InlineHint:
640     return bitc::ATTR_KIND_INLINE_HINT;
641   case Attribute::InReg:
642     return bitc::ATTR_KIND_IN_REG;
643   case Attribute::JumpTable:
644     return bitc::ATTR_KIND_JUMP_TABLE;
645   case Attribute::MinSize:
646     return bitc::ATTR_KIND_MIN_SIZE;
647   case Attribute::Naked:
648     return bitc::ATTR_KIND_NAKED;
649   case Attribute::Nest:
650     return bitc::ATTR_KIND_NEST;
651   case Attribute::NoAlias:
652     return bitc::ATTR_KIND_NO_ALIAS;
653   case Attribute::NoBuiltin:
654     return bitc::ATTR_KIND_NO_BUILTIN;
655   case Attribute::NoCallback:
656     return bitc::ATTR_KIND_NO_CALLBACK;
657   case Attribute::NoCapture:
658     return bitc::ATTR_KIND_NO_CAPTURE;
659   case Attribute::NoDuplicate:
660     return bitc::ATTR_KIND_NO_DUPLICATE;
661   case Attribute::NoFree:
662     return bitc::ATTR_KIND_NOFREE;
663   case Attribute::NoImplicitFloat:
664     return bitc::ATTR_KIND_NO_IMPLICIT_FLOAT;
665   case Attribute::NoInline:
666     return bitc::ATTR_KIND_NO_INLINE;
667   case Attribute::NoRecurse:
668     return bitc::ATTR_KIND_NO_RECURSE;
669   case Attribute::NoMerge:
670     return bitc::ATTR_KIND_NO_MERGE;
671   case Attribute::NonLazyBind:
672     return bitc::ATTR_KIND_NON_LAZY_BIND;
673   case Attribute::NonNull:
674     return bitc::ATTR_KIND_NON_NULL;
675   case Attribute::Dereferenceable:
676     return bitc::ATTR_KIND_DEREFERENCEABLE;
677   case Attribute::DereferenceableOrNull:
678     return bitc::ATTR_KIND_DEREFERENCEABLE_OR_NULL;
679   case Attribute::NoRedZone:
680     return bitc::ATTR_KIND_NO_RED_ZONE;
681   case Attribute::NoReturn:
682     return bitc::ATTR_KIND_NO_RETURN;
683   case Attribute::NoSync:
684     return bitc::ATTR_KIND_NOSYNC;
685   case Attribute::NoCfCheck:
686     return bitc::ATTR_KIND_NOCF_CHECK;
687   case Attribute::NoProfile:
688     return bitc::ATTR_KIND_NO_PROFILE;
689   case Attribute::NoUnwind:
690     return bitc::ATTR_KIND_NO_UNWIND;
691   case Attribute::NoSanitizeCoverage:
692     return bitc::ATTR_KIND_NO_SANITIZE_COVERAGE;
693   case Attribute::NullPointerIsValid:
694     return bitc::ATTR_KIND_NULL_POINTER_IS_VALID;
695   case Attribute::OptForFuzzing:
696     return bitc::ATTR_KIND_OPT_FOR_FUZZING;
697   case Attribute::OptimizeForSize:
698     return bitc::ATTR_KIND_OPTIMIZE_FOR_SIZE;
699   case Attribute::OptimizeNone:
700     return bitc::ATTR_KIND_OPTIMIZE_NONE;
701   case Attribute::ReadNone:
702     return bitc::ATTR_KIND_READ_NONE;
703   case Attribute::ReadOnly:
704     return bitc::ATTR_KIND_READ_ONLY;
705   case Attribute::Returned:
706     return bitc::ATTR_KIND_RETURNED;
707   case Attribute::ReturnsTwice:
708     return bitc::ATTR_KIND_RETURNS_TWICE;
709   case Attribute::SExt:
710     return bitc::ATTR_KIND_S_EXT;
711   case Attribute::Speculatable:
712     return bitc::ATTR_KIND_SPECULATABLE;
713   case Attribute::StackAlignment:
714     return bitc::ATTR_KIND_STACK_ALIGNMENT;
715   case Attribute::StackProtect:
716     return bitc::ATTR_KIND_STACK_PROTECT;
717   case Attribute::StackProtectReq:
718     return bitc::ATTR_KIND_STACK_PROTECT_REQ;
719   case Attribute::StackProtectStrong:
720     return bitc::ATTR_KIND_STACK_PROTECT_STRONG;
721   case Attribute::SafeStack:
722     return bitc::ATTR_KIND_SAFESTACK;
723   case Attribute::ShadowCallStack:
724     return bitc::ATTR_KIND_SHADOWCALLSTACK;
725   case Attribute::StrictFP:
726     return bitc::ATTR_KIND_STRICT_FP;
727   case Attribute::StructRet:
728     return bitc::ATTR_KIND_STRUCT_RET;
729   case Attribute::SanitizeAddress:
730     return bitc::ATTR_KIND_SANITIZE_ADDRESS;
731   case Attribute::SanitizeHWAddress:
732     return bitc::ATTR_KIND_SANITIZE_HWADDRESS;
733   case Attribute::SanitizeThread:
734     return bitc::ATTR_KIND_SANITIZE_THREAD;
735   case Attribute::SanitizeMemory:
736     return bitc::ATTR_KIND_SANITIZE_MEMORY;
737   case Attribute::SpeculativeLoadHardening:
738     return bitc::ATTR_KIND_SPECULATIVE_LOAD_HARDENING;
739   case Attribute::SwiftError:
740     return bitc::ATTR_KIND_SWIFT_ERROR;
741   case Attribute::SwiftSelf:
742     return bitc::ATTR_KIND_SWIFT_SELF;
743   case Attribute::SwiftAsync:
744     return bitc::ATTR_KIND_SWIFT_ASYNC;
745   case Attribute::UWTable:
746     return bitc::ATTR_KIND_UW_TABLE;
747   case Attribute::VScaleRange:
748     return bitc::ATTR_KIND_VSCALE_RANGE;
749   case Attribute::WillReturn:
750     return bitc::ATTR_KIND_WILLRETURN;
751   case Attribute::WriteOnly:
752     return bitc::ATTR_KIND_WRITEONLY;
753   case Attribute::ZExt:
754     return bitc::ATTR_KIND_Z_EXT;
755   case Attribute::ImmArg:
756     return bitc::ATTR_KIND_IMMARG;
757   case Attribute::SanitizeMemTag:
758     return bitc::ATTR_KIND_SANITIZE_MEMTAG;
759   case Attribute::Preallocated:
760     return bitc::ATTR_KIND_PREALLOCATED;
761   case Attribute::NoUndef:
762     return bitc::ATTR_KIND_NOUNDEF;
763   case Attribute::ByRef:
764     return bitc::ATTR_KIND_BYREF;
765   case Attribute::MustProgress:
766     return bitc::ATTR_KIND_MUSTPROGRESS;
767   case Attribute::EndAttrKinds:
768     llvm_unreachable("Can not encode end-attribute kinds marker.");
769   case Attribute::None:
770     llvm_unreachable("Can not encode none-attribute.");
771   case Attribute::EmptyKey:
772   case Attribute::TombstoneKey:
773     llvm_unreachable("Trying to encode EmptyKey/TombstoneKey");
774   }
775 
776   llvm_unreachable("Trying to encode unknown attribute");
777 }
778 
779 void ModuleBitcodeWriter::writeAttributeGroupTable() {
780   const std::vector<ValueEnumerator::IndexAndAttrSet> &AttrGrps =
781       VE.getAttributeGroups();
782   if (AttrGrps.empty()) return;
783 
784   Stream.EnterSubblock(bitc::PARAMATTR_GROUP_BLOCK_ID, 3);
785 
786   SmallVector<uint64_t, 64> Record;
787   for (ValueEnumerator::IndexAndAttrSet Pair : AttrGrps) {
788     unsigned AttrListIndex = Pair.first;
789     AttributeSet AS = Pair.second;
790     Record.push_back(VE.getAttributeGroupID(Pair));
791     Record.push_back(AttrListIndex);
792 
793     for (Attribute Attr : AS) {
794       if (Attr.isEnumAttribute()) {
795         Record.push_back(0);
796         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
797       } else if (Attr.isIntAttribute()) {
798         Record.push_back(1);
799         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
800         Record.push_back(Attr.getValueAsInt());
801       } else if (Attr.isStringAttribute()) {
802         StringRef Kind = Attr.getKindAsString();
803         StringRef Val = Attr.getValueAsString();
804 
805         Record.push_back(Val.empty() ? 3 : 4);
806         Record.append(Kind.begin(), Kind.end());
807         Record.push_back(0);
808         if (!Val.empty()) {
809           Record.append(Val.begin(), Val.end());
810           Record.push_back(0);
811         }
812       } else {
813         assert(Attr.isTypeAttribute());
814         Type *Ty = Attr.getValueAsType();
815         Record.push_back(Ty ? 6 : 5);
816         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
817         if (Ty)
818           Record.push_back(VE.getTypeID(Attr.getValueAsType()));
819       }
820     }
821 
822     Stream.EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
823     Record.clear();
824   }
825 
826   Stream.ExitBlock();
827 }
828 
829 void ModuleBitcodeWriter::writeAttributeTable() {
830   const std::vector<AttributeList> &Attrs = VE.getAttributeLists();
831   if (Attrs.empty()) return;
832 
833   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
834 
835   SmallVector<uint64_t, 64> Record;
836   for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
837     AttributeList AL = Attrs[i];
838     for (unsigned i = AL.index_begin(), e = AL.index_end(); i != e; ++i) {
839       AttributeSet AS = AL.getAttributes(i);
840       if (AS.hasAttributes())
841         Record.push_back(VE.getAttributeGroupID({i, AS}));
842     }
843 
844     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
845     Record.clear();
846   }
847 
848   Stream.ExitBlock();
849 }
850 
851 /// WriteTypeTable - Write out the type table for a module.
852 void ModuleBitcodeWriter::writeTypeTable() {
853   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
854 
855   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
856   SmallVector<uint64_t, 64> TypeVals;
857 
858   uint64_t NumBits = VE.computeBitsRequiredForTypeIndicies();
859 
860   // Abbrev for TYPE_CODE_POINTER.
861   auto Abbv = std::make_shared<BitCodeAbbrev>();
862   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
863   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
864   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
865   unsigned PtrAbbrev = Stream.EmitAbbrev(std::move(Abbv));
866 
867   // Abbrev for TYPE_CODE_OPAQUE_POINTER.
868   Abbv = std::make_shared<BitCodeAbbrev>();
869   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_OPAQUE_POINTER));
870   Abbv->Add(BitCodeAbbrevOp(0)); // Addrspace = 0
871   unsigned OpaquePtrAbbrev = Stream.EmitAbbrev(std::move(Abbv));
872 
873   // Abbrev for TYPE_CODE_FUNCTION.
874   Abbv = std::make_shared<BitCodeAbbrev>();
875   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
876   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
877   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
878   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
879   unsigned FunctionAbbrev = Stream.EmitAbbrev(std::move(Abbv));
880 
881   // Abbrev for TYPE_CODE_STRUCT_ANON.
882   Abbv = std::make_shared<BitCodeAbbrev>();
883   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
884   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
885   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
886   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
887   unsigned StructAnonAbbrev = Stream.EmitAbbrev(std::move(Abbv));
888 
889   // Abbrev for TYPE_CODE_STRUCT_NAME.
890   Abbv = std::make_shared<BitCodeAbbrev>();
891   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
892   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
893   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
894   unsigned StructNameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
895 
896   // Abbrev for TYPE_CODE_STRUCT_NAMED.
897   Abbv = std::make_shared<BitCodeAbbrev>();
898   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
899   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
900   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
901   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
902   unsigned StructNamedAbbrev = Stream.EmitAbbrev(std::move(Abbv));
903 
904   // Abbrev for TYPE_CODE_ARRAY.
905   Abbv = std::make_shared<BitCodeAbbrev>();
906   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
907   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
908   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
909   unsigned ArrayAbbrev = Stream.EmitAbbrev(std::move(Abbv));
910 
911   // Emit an entry count so the reader can reserve space.
912   TypeVals.push_back(TypeList.size());
913   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
914   TypeVals.clear();
915 
916   // Loop over all of the types, emitting each in turn.
917   for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
918     Type *T = TypeList[i];
919     int AbbrevToUse = 0;
920     unsigned Code = 0;
921 
922     switch (T->getTypeID()) {
923     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;      break;
924     case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;      break;
925     case Type::BFloatTyID:    Code = bitc::TYPE_CODE_BFLOAT;    break;
926     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;     break;
927     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE;    break;
928     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80;  break;
929     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128;     break;
930     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
931     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;     break;
932     case Type::MetadataTyID:  Code = bitc::TYPE_CODE_METADATA;  break;
933     case Type::X86_MMXTyID:   Code = bitc::TYPE_CODE_X86_MMX;   break;
934     case Type::X86_AMXTyID:   Code = bitc::TYPE_CODE_X86_AMX;   break;
935     case Type::TokenTyID:     Code = bitc::TYPE_CODE_TOKEN;     break;
936     case Type::IntegerTyID:
937       // INTEGER: [width]
938       Code = bitc::TYPE_CODE_INTEGER;
939       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
940       break;
941     case Type::PointerTyID: {
942       PointerType *PTy = cast<PointerType>(T);
943       unsigned AddressSpace = PTy->getAddressSpace();
944       if (PTy->isOpaque()) {
945         // OPAQUE_POINTER: [address space]
946         Code = bitc::TYPE_CODE_OPAQUE_POINTER;
947         TypeVals.push_back(AddressSpace);
948         if (AddressSpace == 0)
949           AbbrevToUse = OpaquePtrAbbrev;
950       } else {
951         // POINTER: [pointee type, address space]
952         Code = bitc::TYPE_CODE_POINTER;
953         TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
954         TypeVals.push_back(AddressSpace);
955         if (AddressSpace == 0)
956           AbbrevToUse = PtrAbbrev;
957       }
958       break;
959     }
960     case Type::FunctionTyID: {
961       FunctionType *FT = cast<FunctionType>(T);
962       // FUNCTION: [isvararg, retty, paramty x N]
963       Code = bitc::TYPE_CODE_FUNCTION;
964       TypeVals.push_back(FT->isVarArg());
965       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
966       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
967         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
968       AbbrevToUse = FunctionAbbrev;
969       break;
970     }
971     case Type::StructTyID: {
972       StructType *ST = cast<StructType>(T);
973       // STRUCT: [ispacked, eltty x N]
974       TypeVals.push_back(ST->isPacked());
975       // Output all of the element types.
976       for (StructType::element_iterator I = ST->element_begin(),
977            E = ST->element_end(); I != E; ++I)
978         TypeVals.push_back(VE.getTypeID(*I));
979 
980       if (ST->isLiteral()) {
981         Code = bitc::TYPE_CODE_STRUCT_ANON;
982         AbbrevToUse = StructAnonAbbrev;
983       } else {
984         if (ST->isOpaque()) {
985           Code = bitc::TYPE_CODE_OPAQUE;
986         } else {
987           Code = bitc::TYPE_CODE_STRUCT_NAMED;
988           AbbrevToUse = StructNamedAbbrev;
989         }
990 
991         // Emit the name if it is present.
992         if (!ST->getName().empty())
993           writeStringRecord(Stream, bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
994                             StructNameAbbrev);
995       }
996       break;
997     }
998     case Type::ArrayTyID: {
999       ArrayType *AT = cast<ArrayType>(T);
1000       // ARRAY: [numelts, eltty]
1001       Code = bitc::TYPE_CODE_ARRAY;
1002       TypeVals.push_back(AT->getNumElements());
1003       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
1004       AbbrevToUse = ArrayAbbrev;
1005       break;
1006     }
1007     case Type::FixedVectorTyID:
1008     case Type::ScalableVectorTyID: {
1009       VectorType *VT = cast<VectorType>(T);
1010       // VECTOR [numelts, eltty] or
1011       //        [numelts, eltty, scalable]
1012       Code = bitc::TYPE_CODE_VECTOR;
1013       TypeVals.push_back(VT->getElementCount().getKnownMinValue());
1014       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
1015       if (isa<ScalableVectorType>(VT))
1016         TypeVals.push_back(true);
1017       break;
1018     }
1019     }
1020 
1021     // Emit the finished record.
1022     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
1023     TypeVals.clear();
1024   }
1025 
1026   Stream.ExitBlock();
1027 }
1028 
1029 static unsigned getEncodedLinkage(const GlobalValue::LinkageTypes Linkage) {
1030   switch (Linkage) {
1031   case GlobalValue::ExternalLinkage:
1032     return 0;
1033   case GlobalValue::WeakAnyLinkage:
1034     return 16;
1035   case GlobalValue::AppendingLinkage:
1036     return 2;
1037   case GlobalValue::InternalLinkage:
1038     return 3;
1039   case GlobalValue::LinkOnceAnyLinkage:
1040     return 18;
1041   case GlobalValue::ExternalWeakLinkage:
1042     return 7;
1043   case GlobalValue::CommonLinkage:
1044     return 8;
1045   case GlobalValue::PrivateLinkage:
1046     return 9;
1047   case GlobalValue::WeakODRLinkage:
1048     return 17;
1049   case GlobalValue::LinkOnceODRLinkage:
1050     return 19;
1051   case GlobalValue::AvailableExternallyLinkage:
1052     return 12;
1053   }
1054   llvm_unreachable("Invalid linkage");
1055 }
1056 
1057 static unsigned getEncodedLinkage(const GlobalValue &GV) {
1058   return getEncodedLinkage(GV.getLinkage());
1059 }
1060 
1061 static uint64_t getEncodedFFlags(FunctionSummary::FFlags Flags) {
1062   uint64_t RawFlags = 0;
1063   RawFlags |= Flags.ReadNone;
1064   RawFlags |= (Flags.ReadOnly << 1);
1065   RawFlags |= (Flags.NoRecurse << 2);
1066   RawFlags |= (Flags.ReturnDoesNotAlias << 3);
1067   RawFlags |= (Flags.NoInline << 4);
1068   RawFlags |= (Flags.AlwaysInline << 5);
1069   return RawFlags;
1070 }
1071 
1072 // Decode the flags for GlobalValue in the summary. See getDecodedGVSummaryFlags
1073 // in BitcodeReader.cpp.
1074 static uint64_t getEncodedGVSummaryFlags(GlobalValueSummary::GVFlags Flags) {
1075   uint64_t RawFlags = 0;
1076 
1077   RawFlags |= Flags.NotEligibleToImport; // bool
1078   RawFlags |= (Flags.Live << 1);
1079   RawFlags |= (Flags.DSOLocal << 2);
1080   RawFlags |= (Flags.CanAutoHide << 3);
1081 
1082   // Linkage don't need to be remapped at that time for the summary. Any future
1083   // change to the getEncodedLinkage() function will need to be taken into
1084   // account here as well.
1085   RawFlags = (RawFlags << 4) | Flags.Linkage; // 4 bits
1086 
1087   RawFlags |= (Flags.Visibility << 8); // 2 bits
1088 
1089   return RawFlags;
1090 }
1091 
1092 static uint64_t getEncodedGVarFlags(GlobalVarSummary::GVarFlags Flags) {
1093   uint64_t RawFlags = Flags.MaybeReadOnly | (Flags.MaybeWriteOnly << 1) |
1094                       (Flags.Constant << 2) | Flags.VCallVisibility << 3;
1095   return RawFlags;
1096 }
1097 
1098 static unsigned getEncodedVisibility(const GlobalValue &GV) {
1099   switch (GV.getVisibility()) {
1100   case GlobalValue::DefaultVisibility:   return 0;
1101   case GlobalValue::HiddenVisibility:    return 1;
1102   case GlobalValue::ProtectedVisibility: return 2;
1103   }
1104   llvm_unreachable("Invalid visibility");
1105 }
1106 
1107 static unsigned getEncodedDLLStorageClass(const GlobalValue &GV) {
1108   switch (GV.getDLLStorageClass()) {
1109   case GlobalValue::DefaultStorageClass:   return 0;
1110   case GlobalValue::DLLImportStorageClass: return 1;
1111   case GlobalValue::DLLExportStorageClass: return 2;
1112   }
1113   llvm_unreachable("Invalid DLL storage class");
1114 }
1115 
1116 static unsigned getEncodedThreadLocalMode(const GlobalValue &GV) {
1117   switch (GV.getThreadLocalMode()) {
1118     case GlobalVariable::NotThreadLocal:         return 0;
1119     case GlobalVariable::GeneralDynamicTLSModel: return 1;
1120     case GlobalVariable::LocalDynamicTLSModel:   return 2;
1121     case GlobalVariable::InitialExecTLSModel:    return 3;
1122     case GlobalVariable::LocalExecTLSModel:      return 4;
1123   }
1124   llvm_unreachable("Invalid TLS model");
1125 }
1126 
1127 static unsigned getEncodedComdatSelectionKind(const Comdat &C) {
1128   switch (C.getSelectionKind()) {
1129   case Comdat::Any:
1130     return bitc::COMDAT_SELECTION_KIND_ANY;
1131   case Comdat::ExactMatch:
1132     return bitc::COMDAT_SELECTION_KIND_EXACT_MATCH;
1133   case Comdat::Largest:
1134     return bitc::COMDAT_SELECTION_KIND_LARGEST;
1135   case Comdat::NoDeduplicate:
1136     return bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES;
1137   case Comdat::SameSize:
1138     return bitc::COMDAT_SELECTION_KIND_SAME_SIZE;
1139   }
1140   llvm_unreachable("Invalid selection kind");
1141 }
1142 
1143 static unsigned getEncodedUnnamedAddr(const GlobalValue &GV) {
1144   switch (GV.getUnnamedAddr()) {
1145   case GlobalValue::UnnamedAddr::None:   return 0;
1146   case GlobalValue::UnnamedAddr::Local:  return 2;
1147   case GlobalValue::UnnamedAddr::Global: return 1;
1148   }
1149   llvm_unreachable("Invalid unnamed_addr");
1150 }
1151 
1152 size_t ModuleBitcodeWriter::addToStrtab(StringRef Str) {
1153   if (GenerateHash)
1154     Hasher.update(Str);
1155   return StrtabBuilder.add(Str);
1156 }
1157 
1158 void ModuleBitcodeWriter::writeComdats() {
1159   SmallVector<unsigned, 64> Vals;
1160   for (const Comdat *C : VE.getComdats()) {
1161     // COMDAT: [strtab offset, strtab size, selection_kind]
1162     Vals.push_back(addToStrtab(C->getName()));
1163     Vals.push_back(C->getName().size());
1164     Vals.push_back(getEncodedComdatSelectionKind(*C));
1165     Stream.EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
1166     Vals.clear();
1167   }
1168 }
1169 
1170 /// Write a record that will eventually hold the word offset of the
1171 /// module-level VST. For now the offset is 0, which will be backpatched
1172 /// after the real VST is written. Saves the bit offset to backpatch.
1173 void ModuleBitcodeWriter::writeValueSymbolTableForwardDecl() {
1174   // Write a placeholder value in for the offset of the real VST,
1175   // which is written after the function blocks so that it can include
1176   // the offset of each function. The placeholder offset will be
1177   // updated when the real VST is written.
1178   auto Abbv = std::make_shared<BitCodeAbbrev>();
1179   Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_VSTOFFSET));
1180   // Blocks are 32-bit aligned, so we can use a 32-bit word offset to
1181   // hold the real VST offset. Must use fixed instead of VBR as we don't
1182   // know how many VBR chunks to reserve ahead of time.
1183   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
1184   unsigned VSTOffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1185 
1186   // Emit the placeholder
1187   uint64_t Vals[] = {bitc::MODULE_CODE_VSTOFFSET, 0};
1188   Stream.EmitRecordWithAbbrev(VSTOffsetAbbrev, Vals);
1189 
1190   // Compute and save the bit offset to the placeholder, which will be
1191   // patched when the real VST is written. We can simply subtract the 32-bit
1192   // fixed size from the current bit number to get the location to backpatch.
1193   VSTOffsetPlaceholder = Stream.GetCurrentBitNo() - 32;
1194 }
1195 
1196 enum StringEncoding { SE_Char6, SE_Fixed7, SE_Fixed8 };
1197 
1198 /// Determine the encoding to use for the given string name and length.
1199 static StringEncoding getStringEncoding(StringRef Str) {
1200   bool isChar6 = true;
1201   for (char C : Str) {
1202     if (isChar6)
1203       isChar6 = BitCodeAbbrevOp::isChar6(C);
1204     if ((unsigned char)C & 128)
1205       // don't bother scanning the rest.
1206       return SE_Fixed8;
1207   }
1208   if (isChar6)
1209     return SE_Char6;
1210   return SE_Fixed7;
1211 }
1212 
1213 /// Emit top-level description of module, including target triple, inline asm,
1214 /// descriptors for global variables, and function prototype info.
1215 /// Returns the bit offset to backpatch with the location of the real VST.
1216 void ModuleBitcodeWriter::writeModuleInfo() {
1217   // Emit various pieces of data attached to a module.
1218   if (!M.getTargetTriple().empty())
1219     writeStringRecord(Stream, bitc::MODULE_CODE_TRIPLE, M.getTargetTriple(),
1220                       0 /*TODO*/);
1221   const std::string &DL = M.getDataLayoutStr();
1222   if (!DL.empty())
1223     writeStringRecord(Stream, bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/);
1224   if (!M.getModuleInlineAsm().empty())
1225     writeStringRecord(Stream, bitc::MODULE_CODE_ASM, M.getModuleInlineAsm(),
1226                       0 /*TODO*/);
1227 
1228   // Emit information about sections and GC, computing how many there are. Also
1229   // compute the maximum alignment value.
1230   std::map<std::string, unsigned> SectionMap;
1231   std::map<std::string, unsigned> GCMap;
1232   MaybeAlign MaxAlignment;
1233   unsigned MaxGlobalType = 0;
1234   const auto UpdateMaxAlignment = [&MaxAlignment](const MaybeAlign A) {
1235     if (A)
1236       MaxAlignment = !MaxAlignment ? *A : std::max(*MaxAlignment, *A);
1237   };
1238   for (const GlobalVariable &GV : M.globals()) {
1239     UpdateMaxAlignment(GV.getAlign());
1240     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getValueType()));
1241     if (GV.hasSection()) {
1242       // Give section names unique ID's.
1243       unsigned &Entry = SectionMap[std::string(GV.getSection())];
1244       if (!Entry) {
1245         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
1246                           0 /*TODO*/);
1247         Entry = SectionMap.size();
1248       }
1249     }
1250   }
1251   for (const Function &F : M) {
1252     UpdateMaxAlignment(F.getAlign());
1253     if (F.hasSection()) {
1254       // Give section names unique ID's.
1255       unsigned &Entry = SectionMap[std::string(F.getSection())];
1256       if (!Entry) {
1257         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
1258                           0 /*TODO*/);
1259         Entry = SectionMap.size();
1260       }
1261     }
1262     if (F.hasGC()) {
1263       // Same for GC names.
1264       unsigned &Entry = GCMap[F.getGC()];
1265       if (!Entry) {
1266         writeStringRecord(Stream, bitc::MODULE_CODE_GCNAME, F.getGC(),
1267                           0 /*TODO*/);
1268         Entry = GCMap.size();
1269       }
1270     }
1271   }
1272 
1273   // Emit abbrev for globals, now that we know # sections and max alignment.
1274   unsigned SimpleGVarAbbrev = 0;
1275   if (!M.global_empty()) {
1276     // Add an abbrev for common globals with no visibility or thread localness.
1277     auto Abbv = std::make_shared<BitCodeAbbrev>();
1278     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
1279     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1280     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1281     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1282                               Log2_32_Ceil(MaxGlobalType+1)));
1283     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddrSpace << 2
1284                                                            //| explicitType << 1
1285                                                            //| constant
1286     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Initializer.
1287     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // Linkage.
1288     if (!MaxAlignment)                                     // Alignment.
1289       Abbv->Add(BitCodeAbbrevOp(0));
1290     else {
1291       unsigned MaxEncAlignment = getEncodedAlign(MaxAlignment);
1292       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1293                                Log2_32_Ceil(MaxEncAlignment+1)));
1294     }
1295     if (SectionMap.empty())                                    // Section.
1296       Abbv->Add(BitCodeAbbrevOp(0));
1297     else
1298       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1299                                Log2_32_Ceil(SectionMap.size()+1)));
1300     // Don't bother emitting vis + thread local.
1301     SimpleGVarAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1302   }
1303 
1304   SmallVector<unsigned, 64> Vals;
1305   // Emit the module's source file name.
1306   {
1307     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
1308     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
1309     if (Bits == SE_Char6)
1310       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
1311     else if (Bits == SE_Fixed7)
1312       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
1313 
1314     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
1315     auto Abbv = std::make_shared<BitCodeAbbrev>();
1316     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
1317     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1318     Abbv->Add(AbbrevOpToUse);
1319     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1320 
1321     for (const auto P : M.getSourceFileName())
1322       Vals.push_back((unsigned char)P);
1323 
1324     // Emit the finished record.
1325     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
1326     Vals.clear();
1327   }
1328 
1329   // Emit the global variable information.
1330   for (const GlobalVariable &GV : M.globals()) {
1331     unsigned AbbrevToUse = 0;
1332 
1333     // GLOBALVAR: [strtab offset, strtab size, type, isconst, initid,
1334     //             linkage, alignment, section, visibility, threadlocal,
1335     //             unnamed_addr, externally_initialized, dllstorageclass,
1336     //             comdat, attributes, DSO_Local]
1337     Vals.push_back(addToStrtab(GV.getName()));
1338     Vals.push_back(GV.getName().size());
1339     Vals.push_back(VE.getTypeID(GV.getValueType()));
1340     Vals.push_back(GV.getType()->getAddressSpace() << 2 | 2 | GV.isConstant());
1341     Vals.push_back(GV.isDeclaration() ? 0 :
1342                    (VE.getValueID(GV.getInitializer()) + 1));
1343     Vals.push_back(getEncodedLinkage(GV));
1344     Vals.push_back(getEncodedAlign(GV.getAlign()));
1345     Vals.push_back(GV.hasSection() ? SectionMap[std::string(GV.getSection())]
1346                                    : 0);
1347     if (GV.isThreadLocal() ||
1348         GV.getVisibility() != GlobalValue::DefaultVisibility ||
1349         GV.getUnnamedAddr() != GlobalValue::UnnamedAddr::None ||
1350         GV.isExternallyInitialized() ||
1351         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
1352         GV.hasComdat() ||
1353         GV.hasAttributes() ||
1354         GV.isDSOLocal() ||
1355         GV.hasPartition()) {
1356       Vals.push_back(getEncodedVisibility(GV));
1357       Vals.push_back(getEncodedThreadLocalMode(GV));
1358       Vals.push_back(getEncodedUnnamedAddr(GV));
1359       Vals.push_back(GV.isExternallyInitialized());
1360       Vals.push_back(getEncodedDLLStorageClass(GV));
1361       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
1362 
1363       auto AL = GV.getAttributesAsList(AttributeList::FunctionIndex);
1364       Vals.push_back(VE.getAttributeListID(AL));
1365 
1366       Vals.push_back(GV.isDSOLocal());
1367       Vals.push_back(addToStrtab(GV.getPartition()));
1368       Vals.push_back(GV.getPartition().size());
1369     } else {
1370       AbbrevToUse = SimpleGVarAbbrev;
1371     }
1372 
1373     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
1374     Vals.clear();
1375   }
1376 
1377   // Emit the function proto information.
1378   for (const Function &F : M) {
1379     // FUNCTION:  [strtab offset, strtab size, type, callingconv, isproto,
1380     //             linkage, paramattrs, alignment, section, visibility, gc,
1381     //             unnamed_addr, prologuedata, dllstorageclass, comdat,
1382     //             prefixdata, personalityfn, DSO_Local, addrspace]
1383     Vals.push_back(addToStrtab(F.getName()));
1384     Vals.push_back(F.getName().size());
1385     Vals.push_back(VE.getTypeID(F.getFunctionType()));
1386     Vals.push_back(F.getCallingConv());
1387     Vals.push_back(F.isDeclaration());
1388     Vals.push_back(getEncodedLinkage(F));
1389     Vals.push_back(VE.getAttributeListID(F.getAttributes()));
1390     Vals.push_back(getEncodedAlign(F.getAlign()));
1391     Vals.push_back(F.hasSection() ? SectionMap[std::string(F.getSection())]
1392                                   : 0);
1393     Vals.push_back(getEncodedVisibility(F));
1394     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
1395     Vals.push_back(getEncodedUnnamedAddr(F));
1396     Vals.push_back(F.hasPrologueData() ? (VE.getValueID(F.getPrologueData()) + 1)
1397                                        : 0);
1398     Vals.push_back(getEncodedDLLStorageClass(F));
1399     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
1400     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
1401                                      : 0);
1402     Vals.push_back(
1403         F.hasPersonalityFn() ? (VE.getValueID(F.getPersonalityFn()) + 1) : 0);
1404 
1405     Vals.push_back(F.isDSOLocal());
1406     Vals.push_back(F.getAddressSpace());
1407     Vals.push_back(addToStrtab(F.getPartition()));
1408     Vals.push_back(F.getPartition().size());
1409 
1410     unsigned AbbrevToUse = 0;
1411     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
1412     Vals.clear();
1413   }
1414 
1415   // Emit the alias information.
1416   for (const GlobalAlias &A : M.aliases()) {
1417     // ALIAS: [strtab offset, strtab size, alias type, aliasee val#, linkage,
1418     //         visibility, dllstorageclass, threadlocal, unnamed_addr,
1419     //         DSO_Local]
1420     Vals.push_back(addToStrtab(A.getName()));
1421     Vals.push_back(A.getName().size());
1422     Vals.push_back(VE.getTypeID(A.getValueType()));
1423     Vals.push_back(A.getType()->getAddressSpace());
1424     Vals.push_back(VE.getValueID(A.getAliasee()));
1425     Vals.push_back(getEncodedLinkage(A));
1426     Vals.push_back(getEncodedVisibility(A));
1427     Vals.push_back(getEncodedDLLStorageClass(A));
1428     Vals.push_back(getEncodedThreadLocalMode(A));
1429     Vals.push_back(getEncodedUnnamedAddr(A));
1430     Vals.push_back(A.isDSOLocal());
1431     Vals.push_back(addToStrtab(A.getPartition()));
1432     Vals.push_back(A.getPartition().size());
1433 
1434     unsigned AbbrevToUse = 0;
1435     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
1436     Vals.clear();
1437   }
1438 
1439   // Emit the ifunc information.
1440   for (const GlobalIFunc &I : M.ifuncs()) {
1441     // IFUNC: [strtab offset, strtab size, ifunc type, address space, resolver
1442     //         val#, linkage, visibility, DSO_Local]
1443     Vals.push_back(addToStrtab(I.getName()));
1444     Vals.push_back(I.getName().size());
1445     Vals.push_back(VE.getTypeID(I.getValueType()));
1446     Vals.push_back(I.getType()->getAddressSpace());
1447     Vals.push_back(VE.getValueID(I.getResolver()));
1448     Vals.push_back(getEncodedLinkage(I));
1449     Vals.push_back(getEncodedVisibility(I));
1450     Vals.push_back(I.isDSOLocal());
1451     Vals.push_back(addToStrtab(I.getPartition()));
1452     Vals.push_back(I.getPartition().size());
1453     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
1454     Vals.clear();
1455   }
1456 
1457   writeValueSymbolTableForwardDecl();
1458 }
1459 
1460 static uint64_t getOptimizationFlags(const Value *V) {
1461   uint64_t Flags = 0;
1462 
1463   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
1464     if (OBO->hasNoSignedWrap())
1465       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
1466     if (OBO->hasNoUnsignedWrap())
1467       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
1468   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
1469     if (PEO->isExact())
1470       Flags |= 1 << bitc::PEO_EXACT;
1471   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
1472     if (FPMO->hasAllowReassoc())
1473       Flags |= bitc::AllowReassoc;
1474     if (FPMO->hasNoNaNs())
1475       Flags |= bitc::NoNaNs;
1476     if (FPMO->hasNoInfs())
1477       Flags |= bitc::NoInfs;
1478     if (FPMO->hasNoSignedZeros())
1479       Flags |= bitc::NoSignedZeros;
1480     if (FPMO->hasAllowReciprocal())
1481       Flags |= bitc::AllowReciprocal;
1482     if (FPMO->hasAllowContract())
1483       Flags |= bitc::AllowContract;
1484     if (FPMO->hasApproxFunc())
1485       Flags |= bitc::ApproxFunc;
1486   }
1487 
1488   return Flags;
1489 }
1490 
1491 void ModuleBitcodeWriter::writeValueAsMetadata(
1492     const ValueAsMetadata *MD, SmallVectorImpl<uint64_t> &Record) {
1493   // Mimic an MDNode with a value as one operand.
1494   Value *V = MD->getValue();
1495   Record.push_back(VE.getTypeID(V->getType()));
1496   Record.push_back(VE.getValueID(V));
1497   Stream.EmitRecord(bitc::METADATA_VALUE, Record, 0);
1498   Record.clear();
1499 }
1500 
1501 void ModuleBitcodeWriter::writeMDTuple(const MDTuple *N,
1502                                        SmallVectorImpl<uint64_t> &Record,
1503                                        unsigned Abbrev) {
1504   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
1505     Metadata *MD = N->getOperand(i);
1506     assert(!(MD && isa<LocalAsMetadata>(MD)) &&
1507            "Unexpected function-local metadata");
1508     Record.push_back(VE.getMetadataOrNullID(MD));
1509   }
1510   Stream.EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
1511                                     : bitc::METADATA_NODE,
1512                     Record, Abbrev);
1513   Record.clear();
1514 }
1515 
1516 unsigned ModuleBitcodeWriter::createDILocationAbbrev() {
1517   // Assume the column is usually under 128, and always output the inlined-at
1518   // location (it's never more expensive than building an array size 1).
1519   auto Abbv = std::make_shared<BitCodeAbbrev>();
1520   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
1521   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1522   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1523   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1524   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1525   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1526   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1527   return Stream.EmitAbbrev(std::move(Abbv));
1528 }
1529 
1530 void ModuleBitcodeWriter::writeDILocation(const DILocation *N,
1531                                           SmallVectorImpl<uint64_t> &Record,
1532                                           unsigned &Abbrev) {
1533   if (!Abbrev)
1534     Abbrev = createDILocationAbbrev();
1535 
1536   Record.push_back(N->isDistinct());
1537   Record.push_back(N->getLine());
1538   Record.push_back(N->getColumn());
1539   Record.push_back(VE.getMetadataID(N->getScope()));
1540   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
1541   Record.push_back(N->isImplicitCode());
1542 
1543   Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
1544   Record.clear();
1545 }
1546 
1547 unsigned ModuleBitcodeWriter::createGenericDINodeAbbrev() {
1548   // Assume the column is usually under 128, and always output the inlined-at
1549   // location (it's never more expensive than building an array size 1).
1550   auto Abbv = std::make_shared<BitCodeAbbrev>();
1551   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
1552   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1553   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1554   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1555   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1556   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1557   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1558   return Stream.EmitAbbrev(std::move(Abbv));
1559 }
1560 
1561 void ModuleBitcodeWriter::writeGenericDINode(const GenericDINode *N,
1562                                              SmallVectorImpl<uint64_t> &Record,
1563                                              unsigned &Abbrev) {
1564   if (!Abbrev)
1565     Abbrev = createGenericDINodeAbbrev();
1566 
1567   Record.push_back(N->isDistinct());
1568   Record.push_back(N->getTag());
1569   Record.push_back(0); // Per-tag version field; unused for now.
1570 
1571   for (auto &I : N->operands())
1572     Record.push_back(VE.getMetadataOrNullID(I));
1573 
1574   Stream.EmitRecord(bitc::METADATA_GENERIC_DEBUG, Record, Abbrev);
1575   Record.clear();
1576 }
1577 
1578 void ModuleBitcodeWriter::writeDISubrange(const DISubrange *N,
1579                                           SmallVectorImpl<uint64_t> &Record,
1580                                           unsigned Abbrev) {
1581   const uint64_t Version = 2 << 1;
1582   Record.push_back((uint64_t)N->isDistinct() | Version);
1583   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1584   Record.push_back(VE.getMetadataOrNullID(N->getRawLowerBound()));
1585   Record.push_back(VE.getMetadataOrNullID(N->getRawUpperBound()));
1586   Record.push_back(VE.getMetadataOrNullID(N->getRawStride()));
1587 
1588   Stream.EmitRecord(bitc::METADATA_SUBRANGE, Record, Abbrev);
1589   Record.clear();
1590 }
1591 
1592 void ModuleBitcodeWriter::writeDIGenericSubrange(
1593     const DIGenericSubrange *N, SmallVectorImpl<uint64_t> &Record,
1594     unsigned Abbrev) {
1595   Record.push_back((uint64_t)N->isDistinct());
1596   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1597   Record.push_back(VE.getMetadataOrNullID(N->getRawLowerBound()));
1598   Record.push_back(VE.getMetadataOrNullID(N->getRawUpperBound()));
1599   Record.push_back(VE.getMetadataOrNullID(N->getRawStride()));
1600 
1601   Stream.EmitRecord(bitc::METADATA_GENERIC_SUBRANGE, Record, Abbrev);
1602   Record.clear();
1603 }
1604 
1605 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
1606   if ((int64_t)V >= 0)
1607     Vals.push_back(V << 1);
1608   else
1609     Vals.push_back((-V << 1) | 1);
1610 }
1611 
1612 static void emitWideAPInt(SmallVectorImpl<uint64_t> &Vals, const APInt &A) {
1613   // We have an arbitrary precision integer value to write whose
1614   // bit width is > 64. However, in canonical unsigned integer
1615   // format it is likely that the high bits are going to be zero.
1616   // So, we only write the number of active words.
1617   unsigned NumWords = A.getActiveWords();
1618   const uint64_t *RawData = A.getRawData();
1619   for (unsigned i = 0; i < NumWords; i++)
1620     emitSignedInt64(Vals, RawData[i]);
1621 }
1622 
1623 void ModuleBitcodeWriter::writeDIEnumerator(const DIEnumerator *N,
1624                                             SmallVectorImpl<uint64_t> &Record,
1625                                             unsigned Abbrev) {
1626   const uint64_t IsBigInt = 1 << 2;
1627   Record.push_back(IsBigInt | (N->isUnsigned() << 1) | N->isDistinct());
1628   Record.push_back(N->getValue().getBitWidth());
1629   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1630   emitWideAPInt(Record, N->getValue());
1631 
1632   Stream.EmitRecord(bitc::METADATA_ENUMERATOR, Record, Abbrev);
1633   Record.clear();
1634 }
1635 
1636 void ModuleBitcodeWriter::writeDIBasicType(const DIBasicType *N,
1637                                            SmallVectorImpl<uint64_t> &Record,
1638                                            unsigned Abbrev) {
1639   Record.push_back(N->isDistinct());
1640   Record.push_back(N->getTag());
1641   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1642   Record.push_back(N->getSizeInBits());
1643   Record.push_back(N->getAlignInBits());
1644   Record.push_back(N->getEncoding());
1645   Record.push_back(N->getFlags());
1646 
1647   Stream.EmitRecord(bitc::METADATA_BASIC_TYPE, Record, Abbrev);
1648   Record.clear();
1649 }
1650 
1651 void ModuleBitcodeWriter::writeDIStringType(const DIStringType *N,
1652                                             SmallVectorImpl<uint64_t> &Record,
1653                                             unsigned Abbrev) {
1654   Record.push_back(N->isDistinct());
1655   Record.push_back(N->getTag());
1656   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1657   Record.push_back(VE.getMetadataOrNullID(N->getStringLength()));
1658   Record.push_back(VE.getMetadataOrNullID(N->getStringLengthExp()));
1659   Record.push_back(N->getSizeInBits());
1660   Record.push_back(N->getAlignInBits());
1661   Record.push_back(N->getEncoding());
1662 
1663   Stream.EmitRecord(bitc::METADATA_STRING_TYPE, Record, Abbrev);
1664   Record.clear();
1665 }
1666 
1667 void ModuleBitcodeWriter::writeDIDerivedType(const DIDerivedType *N,
1668                                              SmallVectorImpl<uint64_t> &Record,
1669                                              unsigned Abbrev) {
1670   Record.push_back(N->isDistinct());
1671   Record.push_back(N->getTag());
1672   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1673   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1674   Record.push_back(N->getLine());
1675   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1676   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1677   Record.push_back(N->getSizeInBits());
1678   Record.push_back(N->getAlignInBits());
1679   Record.push_back(N->getOffsetInBits());
1680   Record.push_back(N->getFlags());
1681   Record.push_back(VE.getMetadataOrNullID(N->getExtraData()));
1682 
1683   // DWARF address space is encoded as N->getDWARFAddressSpace() + 1. 0 means
1684   // that there is no DWARF address space associated with DIDerivedType.
1685   if (const auto &DWARFAddressSpace = N->getDWARFAddressSpace())
1686     Record.push_back(*DWARFAddressSpace + 1);
1687   else
1688     Record.push_back(0);
1689 
1690   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1691 
1692   Stream.EmitRecord(bitc::METADATA_DERIVED_TYPE, Record, Abbrev);
1693   Record.clear();
1694 }
1695 
1696 void ModuleBitcodeWriter::writeDICompositeType(
1697     const DICompositeType *N, SmallVectorImpl<uint64_t> &Record,
1698     unsigned Abbrev) {
1699   const unsigned IsNotUsedInOldTypeRef = 0x2;
1700   Record.push_back(IsNotUsedInOldTypeRef | (unsigned)N->isDistinct());
1701   Record.push_back(N->getTag());
1702   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1703   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1704   Record.push_back(N->getLine());
1705   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1706   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1707   Record.push_back(N->getSizeInBits());
1708   Record.push_back(N->getAlignInBits());
1709   Record.push_back(N->getOffsetInBits());
1710   Record.push_back(N->getFlags());
1711   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1712   Record.push_back(N->getRuntimeLang());
1713   Record.push_back(VE.getMetadataOrNullID(N->getVTableHolder()));
1714   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1715   Record.push_back(VE.getMetadataOrNullID(N->getRawIdentifier()));
1716   Record.push_back(VE.getMetadataOrNullID(N->getDiscriminator()));
1717   Record.push_back(VE.getMetadataOrNullID(N->getRawDataLocation()));
1718   Record.push_back(VE.getMetadataOrNullID(N->getRawAssociated()));
1719   Record.push_back(VE.getMetadataOrNullID(N->getRawAllocated()));
1720   Record.push_back(VE.getMetadataOrNullID(N->getRawRank()));
1721   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1722 
1723   Stream.EmitRecord(bitc::METADATA_COMPOSITE_TYPE, Record, Abbrev);
1724   Record.clear();
1725 }
1726 
1727 void ModuleBitcodeWriter::writeDISubroutineType(
1728     const DISubroutineType *N, SmallVectorImpl<uint64_t> &Record,
1729     unsigned Abbrev) {
1730   const unsigned HasNoOldTypeRefs = 0x2;
1731   Record.push_back(HasNoOldTypeRefs | (unsigned)N->isDistinct());
1732   Record.push_back(N->getFlags());
1733   Record.push_back(VE.getMetadataOrNullID(N->getTypeArray().get()));
1734   Record.push_back(N->getCC());
1735 
1736   Stream.EmitRecord(bitc::METADATA_SUBROUTINE_TYPE, Record, Abbrev);
1737   Record.clear();
1738 }
1739 
1740 void ModuleBitcodeWriter::writeDIFile(const DIFile *N,
1741                                       SmallVectorImpl<uint64_t> &Record,
1742                                       unsigned Abbrev) {
1743   Record.push_back(N->isDistinct());
1744   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
1745   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
1746   if (N->getRawChecksum()) {
1747     Record.push_back(N->getRawChecksum()->Kind);
1748     Record.push_back(VE.getMetadataOrNullID(N->getRawChecksum()->Value));
1749   } else {
1750     // Maintain backwards compatibility with the old internal representation of
1751     // CSK_None in ChecksumKind by writing nulls here when Checksum is None.
1752     Record.push_back(0);
1753     Record.push_back(VE.getMetadataOrNullID(nullptr));
1754   }
1755   auto Source = N->getRawSource();
1756   if (Source)
1757     Record.push_back(VE.getMetadataOrNullID(*Source));
1758 
1759   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
1760   Record.clear();
1761 }
1762 
1763 void ModuleBitcodeWriter::writeDICompileUnit(const DICompileUnit *N,
1764                                              SmallVectorImpl<uint64_t> &Record,
1765                                              unsigned Abbrev) {
1766   assert(N->isDistinct() && "Expected distinct compile units");
1767   Record.push_back(/* IsDistinct */ true);
1768   Record.push_back(N->getSourceLanguage());
1769   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1770   Record.push_back(VE.getMetadataOrNullID(N->getRawProducer()));
1771   Record.push_back(N->isOptimized());
1772   Record.push_back(VE.getMetadataOrNullID(N->getRawFlags()));
1773   Record.push_back(N->getRuntimeVersion());
1774   Record.push_back(VE.getMetadataOrNullID(N->getRawSplitDebugFilename()));
1775   Record.push_back(N->getEmissionKind());
1776   Record.push_back(VE.getMetadataOrNullID(N->getEnumTypes().get()));
1777   Record.push_back(VE.getMetadataOrNullID(N->getRetainedTypes().get()));
1778   Record.push_back(/* subprograms */ 0);
1779   Record.push_back(VE.getMetadataOrNullID(N->getGlobalVariables().get()));
1780   Record.push_back(VE.getMetadataOrNullID(N->getImportedEntities().get()));
1781   Record.push_back(N->getDWOId());
1782   Record.push_back(VE.getMetadataOrNullID(N->getMacros().get()));
1783   Record.push_back(N->getSplitDebugInlining());
1784   Record.push_back(N->getDebugInfoForProfiling());
1785   Record.push_back((unsigned)N->getNameTableKind());
1786   Record.push_back(N->getRangesBaseAddress());
1787   Record.push_back(VE.getMetadataOrNullID(N->getRawSysRoot()));
1788   Record.push_back(VE.getMetadataOrNullID(N->getRawSDK()));
1789 
1790   Stream.EmitRecord(bitc::METADATA_COMPILE_UNIT, Record, Abbrev);
1791   Record.clear();
1792 }
1793 
1794 void ModuleBitcodeWriter::writeDISubprogram(const DISubprogram *N,
1795                                             SmallVectorImpl<uint64_t> &Record,
1796                                             unsigned Abbrev) {
1797   const uint64_t HasUnitFlag = 1 << 1;
1798   const uint64_t HasSPFlagsFlag = 1 << 2;
1799   Record.push_back(uint64_t(N->isDistinct()) | HasUnitFlag | HasSPFlagsFlag);
1800   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1801   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1802   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1803   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1804   Record.push_back(N->getLine());
1805   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1806   Record.push_back(N->getScopeLine());
1807   Record.push_back(VE.getMetadataOrNullID(N->getContainingType()));
1808   Record.push_back(N->getSPFlags());
1809   Record.push_back(N->getVirtualIndex());
1810   Record.push_back(N->getFlags());
1811   Record.push_back(VE.getMetadataOrNullID(N->getRawUnit()));
1812   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1813   Record.push_back(VE.getMetadataOrNullID(N->getDeclaration()));
1814   Record.push_back(VE.getMetadataOrNullID(N->getRetainedNodes().get()));
1815   Record.push_back(N->getThisAdjustment());
1816   Record.push_back(VE.getMetadataOrNullID(N->getThrownTypes().get()));
1817   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1818 
1819   Stream.EmitRecord(bitc::METADATA_SUBPROGRAM, Record, Abbrev);
1820   Record.clear();
1821 }
1822 
1823 void ModuleBitcodeWriter::writeDILexicalBlock(const DILexicalBlock *N,
1824                                               SmallVectorImpl<uint64_t> &Record,
1825                                               unsigned Abbrev) {
1826   Record.push_back(N->isDistinct());
1827   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1828   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1829   Record.push_back(N->getLine());
1830   Record.push_back(N->getColumn());
1831 
1832   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK, Record, Abbrev);
1833   Record.clear();
1834 }
1835 
1836 void ModuleBitcodeWriter::writeDILexicalBlockFile(
1837     const DILexicalBlockFile *N, SmallVectorImpl<uint64_t> &Record,
1838     unsigned Abbrev) {
1839   Record.push_back(N->isDistinct());
1840   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1841   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1842   Record.push_back(N->getDiscriminator());
1843 
1844   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK_FILE, Record, Abbrev);
1845   Record.clear();
1846 }
1847 
1848 void ModuleBitcodeWriter::writeDICommonBlock(const DICommonBlock *N,
1849                                              SmallVectorImpl<uint64_t> &Record,
1850                                              unsigned Abbrev) {
1851   Record.push_back(N->isDistinct());
1852   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1853   Record.push_back(VE.getMetadataOrNullID(N->getDecl()));
1854   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1855   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1856   Record.push_back(N->getLineNo());
1857 
1858   Stream.EmitRecord(bitc::METADATA_COMMON_BLOCK, Record, Abbrev);
1859   Record.clear();
1860 }
1861 
1862 void ModuleBitcodeWriter::writeDINamespace(const DINamespace *N,
1863                                            SmallVectorImpl<uint64_t> &Record,
1864                                            unsigned Abbrev) {
1865   Record.push_back(N->isDistinct() | N->getExportSymbols() << 1);
1866   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1867   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1868 
1869   Stream.EmitRecord(bitc::METADATA_NAMESPACE, Record, Abbrev);
1870   Record.clear();
1871 }
1872 
1873 void ModuleBitcodeWriter::writeDIMacro(const DIMacro *N,
1874                                        SmallVectorImpl<uint64_t> &Record,
1875                                        unsigned Abbrev) {
1876   Record.push_back(N->isDistinct());
1877   Record.push_back(N->getMacinfoType());
1878   Record.push_back(N->getLine());
1879   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1880   Record.push_back(VE.getMetadataOrNullID(N->getRawValue()));
1881 
1882   Stream.EmitRecord(bitc::METADATA_MACRO, Record, Abbrev);
1883   Record.clear();
1884 }
1885 
1886 void ModuleBitcodeWriter::writeDIMacroFile(const DIMacroFile *N,
1887                                            SmallVectorImpl<uint64_t> &Record,
1888                                            unsigned Abbrev) {
1889   Record.push_back(N->isDistinct());
1890   Record.push_back(N->getMacinfoType());
1891   Record.push_back(N->getLine());
1892   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1893   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1894 
1895   Stream.EmitRecord(bitc::METADATA_MACRO_FILE, Record, Abbrev);
1896   Record.clear();
1897 }
1898 
1899 void ModuleBitcodeWriter::writeDIArgList(const DIArgList *N,
1900                                          SmallVectorImpl<uint64_t> &Record,
1901                                          unsigned Abbrev) {
1902   Record.reserve(N->getArgs().size());
1903   for (ValueAsMetadata *MD : N->getArgs())
1904     Record.push_back(VE.getMetadataID(MD));
1905 
1906   Stream.EmitRecord(bitc::METADATA_ARG_LIST, Record, Abbrev);
1907   Record.clear();
1908 }
1909 
1910 void ModuleBitcodeWriter::writeDIModule(const DIModule *N,
1911                                         SmallVectorImpl<uint64_t> &Record,
1912                                         unsigned Abbrev) {
1913   Record.push_back(N->isDistinct());
1914   for (auto &I : N->operands())
1915     Record.push_back(VE.getMetadataOrNullID(I));
1916   Record.push_back(N->getLineNo());
1917   Record.push_back(N->getIsDecl());
1918 
1919   Stream.EmitRecord(bitc::METADATA_MODULE, Record, Abbrev);
1920   Record.clear();
1921 }
1922 
1923 void ModuleBitcodeWriter::writeDITemplateTypeParameter(
1924     const DITemplateTypeParameter *N, SmallVectorImpl<uint64_t> &Record,
1925     unsigned Abbrev) {
1926   Record.push_back(N->isDistinct());
1927   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1928   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1929   Record.push_back(N->isDefault());
1930 
1931   Stream.EmitRecord(bitc::METADATA_TEMPLATE_TYPE, Record, Abbrev);
1932   Record.clear();
1933 }
1934 
1935 void ModuleBitcodeWriter::writeDITemplateValueParameter(
1936     const DITemplateValueParameter *N, SmallVectorImpl<uint64_t> &Record,
1937     unsigned Abbrev) {
1938   Record.push_back(N->isDistinct());
1939   Record.push_back(N->getTag());
1940   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1941   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1942   Record.push_back(N->isDefault());
1943   Record.push_back(VE.getMetadataOrNullID(N->getValue()));
1944 
1945   Stream.EmitRecord(bitc::METADATA_TEMPLATE_VALUE, Record, Abbrev);
1946   Record.clear();
1947 }
1948 
1949 void ModuleBitcodeWriter::writeDIGlobalVariable(
1950     const DIGlobalVariable *N, SmallVectorImpl<uint64_t> &Record,
1951     unsigned Abbrev) {
1952   const uint64_t Version = 2 << 1;
1953   Record.push_back((uint64_t)N->isDistinct() | Version);
1954   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1955   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1956   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1957   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1958   Record.push_back(N->getLine());
1959   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1960   Record.push_back(N->isLocalToUnit());
1961   Record.push_back(N->isDefinition());
1962   Record.push_back(VE.getMetadataOrNullID(N->getStaticDataMemberDeclaration()));
1963   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams()));
1964   Record.push_back(N->getAlignInBits());
1965   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1966 
1967   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR, Record, Abbrev);
1968   Record.clear();
1969 }
1970 
1971 void ModuleBitcodeWriter::writeDILocalVariable(
1972     const DILocalVariable *N, SmallVectorImpl<uint64_t> &Record,
1973     unsigned Abbrev) {
1974   // In order to support all possible bitcode formats in BitcodeReader we need
1975   // to distinguish the following cases:
1976   // 1) Record has no artificial tag (Record[1]),
1977   //   has no obsolete inlinedAt field (Record[9]).
1978   //   In this case Record size will be 8, HasAlignment flag is false.
1979   // 2) Record has artificial tag (Record[1]),
1980   //   has no obsolete inlignedAt field (Record[9]).
1981   //   In this case Record size will be 9, HasAlignment flag is false.
1982   // 3) Record has both artificial tag (Record[1]) and
1983   //   obsolete inlignedAt field (Record[9]).
1984   //   In this case Record size will be 10, HasAlignment flag is false.
1985   // 4) Record has neither artificial tag, nor inlignedAt field, but
1986   //   HasAlignment flag is true and Record[8] contains alignment value.
1987   const uint64_t HasAlignmentFlag = 1 << 1;
1988   Record.push_back((uint64_t)N->isDistinct() | HasAlignmentFlag);
1989   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1990   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1991   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1992   Record.push_back(N->getLine());
1993   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1994   Record.push_back(N->getArg());
1995   Record.push_back(N->getFlags());
1996   Record.push_back(N->getAlignInBits());
1997   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1998 
1999   Stream.EmitRecord(bitc::METADATA_LOCAL_VAR, Record, Abbrev);
2000   Record.clear();
2001 }
2002 
2003 void ModuleBitcodeWriter::writeDILabel(
2004     const DILabel *N, SmallVectorImpl<uint64_t> &Record,
2005     unsigned Abbrev) {
2006   Record.push_back((uint64_t)N->isDistinct());
2007   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2008   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2009   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2010   Record.push_back(N->getLine());
2011 
2012   Stream.EmitRecord(bitc::METADATA_LABEL, Record, Abbrev);
2013   Record.clear();
2014 }
2015 
2016 void ModuleBitcodeWriter::writeDIExpression(const DIExpression *N,
2017                                             SmallVectorImpl<uint64_t> &Record,
2018                                             unsigned Abbrev) {
2019   Record.reserve(N->getElements().size() + 1);
2020   const uint64_t Version = 3 << 1;
2021   Record.push_back((uint64_t)N->isDistinct() | Version);
2022   Record.append(N->elements_begin(), N->elements_end());
2023 
2024   Stream.EmitRecord(bitc::METADATA_EXPRESSION, Record, Abbrev);
2025   Record.clear();
2026 }
2027 
2028 void ModuleBitcodeWriter::writeDIGlobalVariableExpression(
2029     const DIGlobalVariableExpression *N, SmallVectorImpl<uint64_t> &Record,
2030     unsigned Abbrev) {
2031   Record.push_back(N->isDistinct());
2032   Record.push_back(VE.getMetadataOrNullID(N->getVariable()));
2033   Record.push_back(VE.getMetadataOrNullID(N->getExpression()));
2034 
2035   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR_EXPR, Record, Abbrev);
2036   Record.clear();
2037 }
2038 
2039 void ModuleBitcodeWriter::writeDIObjCProperty(const DIObjCProperty *N,
2040                                               SmallVectorImpl<uint64_t> &Record,
2041                                               unsigned Abbrev) {
2042   Record.push_back(N->isDistinct());
2043   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2044   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2045   Record.push_back(N->getLine());
2046   Record.push_back(VE.getMetadataOrNullID(N->getRawSetterName()));
2047   Record.push_back(VE.getMetadataOrNullID(N->getRawGetterName()));
2048   Record.push_back(N->getAttributes());
2049   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2050 
2051   Stream.EmitRecord(bitc::METADATA_OBJC_PROPERTY, Record, Abbrev);
2052   Record.clear();
2053 }
2054 
2055 void ModuleBitcodeWriter::writeDIImportedEntity(
2056     const DIImportedEntity *N, SmallVectorImpl<uint64_t> &Record,
2057     unsigned Abbrev) {
2058   Record.push_back(N->isDistinct());
2059   Record.push_back(N->getTag());
2060   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2061   Record.push_back(VE.getMetadataOrNullID(N->getEntity()));
2062   Record.push_back(N->getLine());
2063   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2064   Record.push_back(VE.getMetadataOrNullID(N->getRawFile()));
2065 
2066   Stream.EmitRecord(bitc::METADATA_IMPORTED_ENTITY, Record, Abbrev);
2067   Record.clear();
2068 }
2069 
2070 unsigned ModuleBitcodeWriter::createNamedMetadataAbbrev() {
2071   auto Abbv = std::make_shared<BitCodeAbbrev>();
2072   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
2073   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2074   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2075   return Stream.EmitAbbrev(std::move(Abbv));
2076 }
2077 
2078 void ModuleBitcodeWriter::writeNamedMetadata(
2079     SmallVectorImpl<uint64_t> &Record) {
2080   if (M.named_metadata_empty())
2081     return;
2082 
2083   unsigned Abbrev = createNamedMetadataAbbrev();
2084   for (const NamedMDNode &NMD : M.named_metadata()) {
2085     // Write name.
2086     StringRef Str = NMD.getName();
2087     Record.append(Str.bytes_begin(), Str.bytes_end());
2088     Stream.EmitRecord(bitc::METADATA_NAME, Record, Abbrev);
2089     Record.clear();
2090 
2091     // Write named metadata operands.
2092     for (const MDNode *N : NMD.operands())
2093       Record.push_back(VE.getMetadataID(N));
2094     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
2095     Record.clear();
2096   }
2097 }
2098 
2099 unsigned ModuleBitcodeWriter::createMetadataStringsAbbrev() {
2100   auto Abbv = std::make_shared<BitCodeAbbrev>();
2101   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRINGS));
2102   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // # of strings
2103   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // offset to chars
2104   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
2105   return Stream.EmitAbbrev(std::move(Abbv));
2106 }
2107 
2108 /// Write out a record for MDString.
2109 ///
2110 /// All the metadata strings in a metadata block are emitted in a single
2111 /// record.  The sizes and strings themselves are shoved into a blob.
2112 void ModuleBitcodeWriter::writeMetadataStrings(
2113     ArrayRef<const Metadata *> Strings, SmallVectorImpl<uint64_t> &Record) {
2114   if (Strings.empty())
2115     return;
2116 
2117   // Start the record with the number of strings.
2118   Record.push_back(bitc::METADATA_STRINGS);
2119   Record.push_back(Strings.size());
2120 
2121   // Emit the sizes of the strings in the blob.
2122   SmallString<256> Blob;
2123   {
2124     BitstreamWriter W(Blob);
2125     for (const Metadata *MD : Strings)
2126       W.EmitVBR(cast<MDString>(MD)->getLength(), 6);
2127     W.FlushToWord();
2128   }
2129 
2130   // Add the offset to the strings to the record.
2131   Record.push_back(Blob.size());
2132 
2133   // Add the strings to the blob.
2134   for (const Metadata *MD : Strings)
2135     Blob.append(cast<MDString>(MD)->getString());
2136 
2137   // Emit the final record.
2138   Stream.EmitRecordWithBlob(createMetadataStringsAbbrev(), Record, Blob);
2139   Record.clear();
2140 }
2141 
2142 // Generates an enum to use as an index in the Abbrev array of Metadata record.
2143 enum MetadataAbbrev : unsigned {
2144 #define HANDLE_MDNODE_LEAF(CLASS) CLASS##AbbrevID,
2145 #include "llvm/IR/Metadata.def"
2146   LastPlusOne
2147 };
2148 
2149 void ModuleBitcodeWriter::writeMetadataRecords(
2150     ArrayRef<const Metadata *> MDs, SmallVectorImpl<uint64_t> &Record,
2151     std::vector<unsigned> *MDAbbrevs, std::vector<uint64_t> *IndexPos) {
2152   if (MDs.empty())
2153     return;
2154 
2155   // Initialize MDNode abbreviations.
2156 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
2157 #include "llvm/IR/Metadata.def"
2158 
2159   for (const Metadata *MD : MDs) {
2160     if (IndexPos)
2161       IndexPos->push_back(Stream.GetCurrentBitNo());
2162     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
2163       assert(N->isResolved() && "Expected forward references to be resolved");
2164 
2165       switch (N->getMetadataID()) {
2166       default:
2167         llvm_unreachable("Invalid MDNode subclass");
2168 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
2169   case Metadata::CLASS##Kind:                                                  \
2170     if (MDAbbrevs)                                                             \
2171       write##CLASS(cast<CLASS>(N), Record,                                     \
2172                    (*MDAbbrevs)[MetadataAbbrev::CLASS##AbbrevID]);             \
2173     else                                                                       \
2174       write##CLASS(cast<CLASS>(N), Record, CLASS##Abbrev);                     \
2175     continue;
2176 #include "llvm/IR/Metadata.def"
2177       }
2178     }
2179     writeValueAsMetadata(cast<ValueAsMetadata>(MD), Record);
2180   }
2181 }
2182 
2183 void ModuleBitcodeWriter::writeModuleMetadata() {
2184   if (!VE.hasMDs() && M.named_metadata_empty())
2185     return;
2186 
2187   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 4);
2188   SmallVector<uint64_t, 64> Record;
2189 
2190   // Emit all abbrevs upfront, so that the reader can jump in the middle of the
2191   // block and load any metadata.
2192   std::vector<unsigned> MDAbbrevs;
2193 
2194   MDAbbrevs.resize(MetadataAbbrev::LastPlusOne);
2195   MDAbbrevs[MetadataAbbrev::DILocationAbbrevID] = createDILocationAbbrev();
2196   MDAbbrevs[MetadataAbbrev::GenericDINodeAbbrevID] =
2197       createGenericDINodeAbbrev();
2198 
2199   auto Abbv = std::make_shared<BitCodeAbbrev>();
2200   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX_OFFSET));
2201   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2202   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2203   unsigned OffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2204 
2205   Abbv = std::make_shared<BitCodeAbbrev>();
2206   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX));
2207   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2208   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2209   unsigned IndexAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2210 
2211   // Emit MDStrings together upfront.
2212   writeMetadataStrings(VE.getMDStrings(), Record);
2213 
2214   // We only emit an index for the metadata record if we have more than a given
2215   // (naive) threshold of metadatas, otherwise it is not worth it.
2216   if (VE.getNonMDStrings().size() > IndexThreshold) {
2217     // Write a placeholder value in for the offset of the metadata index,
2218     // which is written after the records, so that it can include
2219     // the offset of each entry. The placeholder offset will be
2220     // updated after all records are emitted.
2221     uint64_t Vals[] = {0, 0};
2222     Stream.EmitRecord(bitc::METADATA_INDEX_OFFSET, Vals, OffsetAbbrev);
2223   }
2224 
2225   // Compute and save the bit offset to the current position, which will be
2226   // patched when we emit the index later. We can simply subtract the 64-bit
2227   // fixed size from the current bit number to get the location to backpatch.
2228   uint64_t IndexOffsetRecordBitPos = Stream.GetCurrentBitNo();
2229 
2230   // This index will contain the bitpos for each individual record.
2231   std::vector<uint64_t> IndexPos;
2232   IndexPos.reserve(VE.getNonMDStrings().size());
2233 
2234   // Write all the records
2235   writeMetadataRecords(VE.getNonMDStrings(), Record, &MDAbbrevs, &IndexPos);
2236 
2237   if (VE.getNonMDStrings().size() > IndexThreshold) {
2238     // Now that we have emitted all the records we will emit the index. But
2239     // first
2240     // backpatch the forward reference so that the reader can skip the records
2241     // efficiently.
2242     Stream.BackpatchWord64(IndexOffsetRecordBitPos - 64,
2243                            Stream.GetCurrentBitNo() - IndexOffsetRecordBitPos);
2244 
2245     // Delta encode the index.
2246     uint64_t PreviousValue = IndexOffsetRecordBitPos;
2247     for (auto &Elt : IndexPos) {
2248       auto EltDelta = Elt - PreviousValue;
2249       PreviousValue = Elt;
2250       Elt = EltDelta;
2251     }
2252     // Emit the index record.
2253     Stream.EmitRecord(bitc::METADATA_INDEX, IndexPos, IndexAbbrev);
2254     IndexPos.clear();
2255   }
2256 
2257   // Write the named metadata now.
2258   writeNamedMetadata(Record);
2259 
2260   auto AddDeclAttachedMetadata = [&](const GlobalObject &GO) {
2261     SmallVector<uint64_t, 4> Record;
2262     Record.push_back(VE.getValueID(&GO));
2263     pushGlobalMetadataAttachment(Record, GO);
2264     Stream.EmitRecord(bitc::METADATA_GLOBAL_DECL_ATTACHMENT, Record);
2265   };
2266   for (const Function &F : M)
2267     if (F.isDeclaration() && F.hasMetadata())
2268       AddDeclAttachedMetadata(F);
2269   // FIXME: Only store metadata for declarations here, and move data for global
2270   // variable definitions to a separate block (PR28134).
2271   for (const GlobalVariable &GV : M.globals())
2272     if (GV.hasMetadata())
2273       AddDeclAttachedMetadata(GV);
2274 
2275   Stream.ExitBlock();
2276 }
2277 
2278 void ModuleBitcodeWriter::writeFunctionMetadata(const Function &F) {
2279   if (!VE.hasMDs())
2280     return;
2281 
2282   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
2283   SmallVector<uint64_t, 64> Record;
2284   writeMetadataStrings(VE.getMDStrings(), Record);
2285   writeMetadataRecords(VE.getNonMDStrings(), Record);
2286   Stream.ExitBlock();
2287 }
2288 
2289 void ModuleBitcodeWriter::pushGlobalMetadataAttachment(
2290     SmallVectorImpl<uint64_t> &Record, const GlobalObject &GO) {
2291   // [n x [id, mdnode]]
2292   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2293   GO.getAllMetadata(MDs);
2294   for (const auto &I : MDs) {
2295     Record.push_back(I.first);
2296     Record.push_back(VE.getMetadataID(I.second));
2297   }
2298 }
2299 
2300 void ModuleBitcodeWriter::writeFunctionMetadataAttachment(const Function &F) {
2301   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
2302 
2303   SmallVector<uint64_t, 64> Record;
2304 
2305   if (F.hasMetadata()) {
2306     pushGlobalMetadataAttachment(Record, F);
2307     Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2308     Record.clear();
2309   }
2310 
2311   // Write metadata attachments
2312   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
2313   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2314   for (const BasicBlock &BB : F)
2315     for (const Instruction &I : BB) {
2316       MDs.clear();
2317       I.getAllMetadataOtherThanDebugLoc(MDs);
2318 
2319       // If no metadata, ignore instruction.
2320       if (MDs.empty()) continue;
2321 
2322       Record.push_back(VE.getInstructionID(&I));
2323 
2324       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
2325         Record.push_back(MDs[i].first);
2326         Record.push_back(VE.getMetadataID(MDs[i].second));
2327       }
2328       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2329       Record.clear();
2330     }
2331 
2332   Stream.ExitBlock();
2333 }
2334 
2335 void ModuleBitcodeWriter::writeModuleMetadataKinds() {
2336   SmallVector<uint64_t, 64> Record;
2337 
2338   // Write metadata kinds
2339   // METADATA_KIND - [n x [id, name]]
2340   SmallVector<StringRef, 8> Names;
2341   M.getMDKindNames(Names);
2342 
2343   if (Names.empty()) return;
2344 
2345   Stream.EnterSubblock(bitc::METADATA_KIND_BLOCK_ID, 3);
2346 
2347   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
2348     Record.push_back(MDKindID);
2349     StringRef KName = Names[MDKindID];
2350     Record.append(KName.begin(), KName.end());
2351 
2352     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
2353     Record.clear();
2354   }
2355 
2356   Stream.ExitBlock();
2357 }
2358 
2359 void ModuleBitcodeWriter::writeOperandBundleTags() {
2360   // Write metadata kinds
2361   //
2362   // OPERAND_BUNDLE_TAGS_BLOCK_ID : N x OPERAND_BUNDLE_TAG
2363   //
2364   // OPERAND_BUNDLE_TAG - [strchr x N]
2365 
2366   SmallVector<StringRef, 8> Tags;
2367   M.getOperandBundleTags(Tags);
2368 
2369   if (Tags.empty())
2370     return;
2371 
2372   Stream.EnterSubblock(bitc::OPERAND_BUNDLE_TAGS_BLOCK_ID, 3);
2373 
2374   SmallVector<uint64_t, 64> Record;
2375 
2376   for (auto Tag : Tags) {
2377     Record.append(Tag.begin(), Tag.end());
2378 
2379     Stream.EmitRecord(bitc::OPERAND_BUNDLE_TAG, Record, 0);
2380     Record.clear();
2381   }
2382 
2383   Stream.ExitBlock();
2384 }
2385 
2386 void ModuleBitcodeWriter::writeSyncScopeNames() {
2387   SmallVector<StringRef, 8> SSNs;
2388   M.getContext().getSyncScopeNames(SSNs);
2389   if (SSNs.empty())
2390     return;
2391 
2392   Stream.EnterSubblock(bitc::SYNC_SCOPE_NAMES_BLOCK_ID, 2);
2393 
2394   SmallVector<uint64_t, 64> Record;
2395   for (auto SSN : SSNs) {
2396     Record.append(SSN.begin(), SSN.end());
2397     Stream.EmitRecord(bitc::SYNC_SCOPE_NAME, Record, 0);
2398     Record.clear();
2399   }
2400 
2401   Stream.ExitBlock();
2402 }
2403 
2404 void ModuleBitcodeWriter::writeConstants(unsigned FirstVal, unsigned LastVal,
2405                                          bool isGlobal) {
2406   if (FirstVal == LastVal) return;
2407 
2408   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
2409 
2410   unsigned AggregateAbbrev = 0;
2411   unsigned String8Abbrev = 0;
2412   unsigned CString7Abbrev = 0;
2413   unsigned CString6Abbrev = 0;
2414   // If this is a constant pool for the module, emit module-specific abbrevs.
2415   if (isGlobal) {
2416     // Abbrev for CST_CODE_AGGREGATE.
2417     auto Abbv = std::make_shared<BitCodeAbbrev>();
2418     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
2419     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2420     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
2421     AggregateAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2422 
2423     // Abbrev for CST_CODE_STRING.
2424     Abbv = std::make_shared<BitCodeAbbrev>();
2425     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
2426     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2427     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2428     String8Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2429     // Abbrev for CST_CODE_CSTRING.
2430     Abbv = std::make_shared<BitCodeAbbrev>();
2431     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2432     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2433     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2434     CString7Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2435     // Abbrev for CST_CODE_CSTRING.
2436     Abbv = std::make_shared<BitCodeAbbrev>();
2437     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2438     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2439     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2440     CString6Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2441   }
2442 
2443   SmallVector<uint64_t, 64> Record;
2444 
2445   const ValueEnumerator::ValueList &Vals = VE.getValues();
2446   Type *LastTy = nullptr;
2447   for (unsigned i = FirstVal; i != LastVal; ++i) {
2448     const Value *V = Vals[i].first;
2449     // If we need to switch types, do so now.
2450     if (V->getType() != LastTy) {
2451       LastTy = V->getType();
2452       Record.push_back(VE.getTypeID(LastTy));
2453       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
2454                         CONSTANTS_SETTYPE_ABBREV);
2455       Record.clear();
2456     }
2457 
2458     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
2459       Record.push_back(
2460           unsigned(IA->hasSideEffects()) | unsigned(IA->isAlignStack()) << 1 |
2461           unsigned(IA->getDialect() & 1) << 2 | unsigned(IA->canThrow()) << 3);
2462 
2463       // Add the asm string.
2464       const std::string &AsmStr = IA->getAsmString();
2465       Record.push_back(AsmStr.size());
2466       Record.append(AsmStr.begin(), AsmStr.end());
2467 
2468       // Add the constraint string.
2469       const std::string &ConstraintStr = IA->getConstraintString();
2470       Record.push_back(ConstraintStr.size());
2471       Record.append(ConstraintStr.begin(), ConstraintStr.end());
2472       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
2473       Record.clear();
2474       continue;
2475     }
2476     const Constant *C = cast<Constant>(V);
2477     unsigned Code = -1U;
2478     unsigned AbbrevToUse = 0;
2479     if (C->isNullValue()) {
2480       Code = bitc::CST_CODE_NULL;
2481     } else if (isa<PoisonValue>(C)) {
2482       Code = bitc::CST_CODE_POISON;
2483     } else if (isa<UndefValue>(C)) {
2484       Code = bitc::CST_CODE_UNDEF;
2485     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
2486       if (IV->getBitWidth() <= 64) {
2487         uint64_t V = IV->getSExtValue();
2488         emitSignedInt64(Record, V);
2489         Code = bitc::CST_CODE_INTEGER;
2490         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
2491       } else {                             // Wide integers, > 64 bits in size.
2492         emitWideAPInt(Record, IV->getValue());
2493         Code = bitc::CST_CODE_WIDE_INTEGER;
2494       }
2495     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
2496       Code = bitc::CST_CODE_FLOAT;
2497       Type *Ty = CFP->getType();
2498       if (Ty->isHalfTy() || Ty->isBFloatTy() || Ty->isFloatTy() ||
2499           Ty->isDoubleTy()) {
2500         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
2501       } else if (Ty->isX86_FP80Ty()) {
2502         // api needed to prevent premature destruction
2503         // bits are not in the same order as a normal i80 APInt, compensate.
2504         APInt api = CFP->getValueAPF().bitcastToAPInt();
2505         const uint64_t *p = api.getRawData();
2506         Record.push_back((p[1] << 48) | (p[0] >> 16));
2507         Record.push_back(p[0] & 0xffffLL);
2508       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
2509         APInt api = CFP->getValueAPF().bitcastToAPInt();
2510         const uint64_t *p = api.getRawData();
2511         Record.push_back(p[0]);
2512         Record.push_back(p[1]);
2513       } else {
2514         assert(0 && "Unknown FP type!");
2515       }
2516     } else if (isa<ConstantDataSequential>(C) &&
2517                cast<ConstantDataSequential>(C)->isString()) {
2518       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
2519       // Emit constant strings specially.
2520       unsigned NumElts = Str->getNumElements();
2521       // If this is a null-terminated string, use the denser CSTRING encoding.
2522       if (Str->isCString()) {
2523         Code = bitc::CST_CODE_CSTRING;
2524         --NumElts;  // Don't encode the null, which isn't allowed by char6.
2525       } else {
2526         Code = bitc::CST_CODE_STRING;
2527         AbbrevToUse = String8Abbrev;
2528       }
2529       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
2530       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
2531       for (unsigned i = 0; i != NumElts; ++i) {
2532         unsigned char V = Str->getElementAsInteger(i);
2533         Record.push_back(V);
2534         isCStr7 &= (V & 128) == 0;
2535         if (isCStrChar6)
2536           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
2537       }
2538 
2539       if (isCStrChar6)
2540         AbbrevToUse = CString6Abbrev;
2541       else if (isCStr7)
2542         AbbrevToUse = CString7Abbrev;
2543     } else if (const ConstantDataSequential *CDS =
2544                   dyn_cast<ConstantDataSequential>(C)) {
2545       Code = bitc::CST_CODE_DATA;
2546       Type *EltTy = CDS->getElementType();
2547       if (isa<IntegerType>(EltTy)) {
2548         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2549           Record.push_back(CDS->getElementAsInteger(i));
2550       } else {
2551         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2552           Record.push_back(
2553               CDS->getElementAsAPFloat(i).bitcastToAPInt().getLimitedValue());
2554       }
2555     } else if (isa<ConstantAggregate>(C)) {
2556       Code = bitc::CST_CODE_AGGREGATE;
2557       for (const Value *Op : C->operands())
2558         Record.push_back(VE.getValueID(Op));
2559       AbbrevToUse = AggregateAbbrev;
2560     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
2561       switch (CE->getOpcode()) {
2562       default:
2563         if (Instruction::isCast(CE->getOpcode())) {
2564           Code = bitc::CST_CODE_CE_CAST;
2565           Record.push_back(getEncodedCastOpcode(CE->getOpcode()));
2566           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2567           Record.push_back(VE.getValueID(C->getOperand(0)));
2568           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
2569         } else {
2570           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
2571           Code = bitc::CST_CODE_CE_BINOP;
2572           Record.push_back(getEncodedBinaryOpcode(CE->getOpcode()));
2573           Record.push_back(VE.getValueID(C->getOperand(0)));
2574           Record.push_back(VE.getValueID(C->getOperand(1)));
2575           uint64_t Flags = getOptimizationFlags(CE);
2576           if (Flags != 0)
2577             Record.push_back(Flags);
2578         }
2579         break;
2580       case Instruction::FNeg: {
2581         assert(CE->getNumOperands() == 1 && "Unknown constant expr!");
2582         Code = bitc::CST_CODE_CE_UNOP;
2583         Record.push_back(getEncodedUnaryOpcode(CE->getOpcode()));
2584         Record.push_back(VE.getValueID(C->getOperand(0)));
2585         uint64_t Flags = getOptimizationFlags(CE);
2586         if (Flags != 0)
2587           Record.push_back(Flags);
2588         break;
2589       }
2590       case Instruction::GetElementPtr: {
2591         Code = bitc::CST_CODE_CE_GEP;
2592         const auto *GO = cast<GEPOperator>(C);
2593         Record.push_back(VE.getTypeID(GO->getSourceElementType()));
2594         if (Optional<unsigned> Idx = GO->getInRangeIndex()) {
2595           Code = bitc::CST_CODE_CE_GEP_WITH_INRANGE_INDEX;
2596           Record.push_back((*Idx << 1) | GO->isInBounds());
2597         } else if (GO->isInBounds())
2598           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
2599         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
2600           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
2601           Record.push_back(VE.getValueID(C->getOperand(i)));
2602         }
2603         break;
2604       }
2605       case Instruction::Select:
2606         Code = bitc::CST_CODE_CE_SELECT;
2607         Record.push_back(VE.getValueID(C->getOperand(0)));
2608         Record.push_back(VE.getValueID(C->getOperand(1)));
2609         Record.push_back(VE.getValueID(C->getOperand(2)));
2610         break;
2611       case Instruction::ExtractElement:
2612         Code = bitc::CST_CODE_CE_EXTRACTELT;
2613         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2614         Record.push_back(VE.getValueID(C->getOperand(0)));
2615         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
2616         Record.push_back(VE.getValueID(C->getOperand(1)));
2617         break;
2618       case Instruction::InsertElement:
2619         Code = bitc::CST_CODE_CE_INSERTELT;
2620         Record.push_back(VE.getValueID(C->getOperand(0)));
2621         Record.push_back(VE.getValueID(C->getOperand(1)));
2622         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
2623         Record.push_back(VE.getValueID(C->getOperand(2)));
2624         break;
2625       case Instruction::ShuffleVector:
2626         // If the return type and argument types are the same, this is a
2627         // standard shufflevector instruction.  If the types are different,
2628         // then the shuffle is widening or truncating the input vectors, and
2629         // the argument type must also be encoded.
2630         if (C->getType() == C->getOperand(0)->getType()) {
2631           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
2632         } else {
2633           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
2634           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2635         }
2636         Record.push_back(VE.getValueID(C->getOperand(0)));
2637         Record.push_back(VE.getValueID(C->getOperand(1)));
2638         Record.push_back(VE.getValueID(CE->getShuffleMaskForBitcode()));
2639         break;
2640       case Instruction::ICmp:
2641       case Instruction::FCmp:
2642         Code = bitc::CST_CODE_CE_CMP;
2643         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2644         Record.push_back(VE.getValueID(C->getOperand(0)));
2645         Record.push_back(VE.getValueID(C->getOperand(1)));
2646         Record.push_back(CE->getPredicate());
2647         break;
2648       }
2649     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
2650       Code = bitc::CST_CODE_BLOCKADDRESS;
2651       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
2652       Record.push_back(VE.getValueID(BA->getFunction()));
2653       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
2654     } else if (const auto *Equiv = dyn_cast<DSOLocalEquivalent>(C)) {
2655       Code = bitc::CST_CODE_DSO_LOCAL_EQUIVALENT;
2656       Record.push_back(VE.getTypeID(Equiv->getGlobalValue()->getType()));
2657       Record.push_back(VE.getValueID(Equiv->getGlobalValue()));
2658     } else {
2659 #ifndef NDEBUG
2660       C->dump();
2661 #endif
2662       llvm_unreachable("Unknown constant!");
2663     }
2664     Stream.EmitRecord(Code, Record, AbbrevToUse);
2665     Record.clear();
2666   }
2667 
2668   Stream.ExitBlock();
2669 }
2670 
2671 void ModuleBitcodeWriter::writeModuleConstants() {
2672   const ValueEnumerator::ValueList &Vals = VE.getValues();
2673 
2674   // Find the first constant to emit, which is the first non-globalvalue value.
2675   // We know globalvalues have been emitted by WriteModuleInfo.
2676   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
2677     if (!isa<GlobalValue>(Vals[i].first)) {
2678       writeConstants(i, Vals.size(), true);
2679       return;
2680     }
2681   }
2682 }
2683 
2684 /// pushValueAndType - The file has to encode both the value and type id for
2685 /// many values, because we need to know what type to create for forward
2686 /// references.  However, most operands are not forward references, so this type
2687 /// field is not needed.
2688 ///
2689 /// This function adds V's value ID to Vals.  If the value ID is higher than the
2690 /// instruction ID, then it is a forward reference, and it also includes the
2691 /// type ID.  The value ID that is written is encoded relative to the InstID.
2692 bool ModuleBitcodeWriter::pushValueAndType(const Value *V, unsigned InstID,
2693                                            SmallVectorImpl<unsigned> &Vals) {
2694   unsigned ValID = VE.getValueID(V);
2695   // Make encoding relative to the InstID.
2696   Vals.push_back(InstID - ValID);
2697   if (ValID >= InstID) {
2698     Vals.push_back(VE.getTypeID(V->getType()));
2699     return true;
2700   }
2701   return false;
2702 }
2703 
2704 void ModuleBitcodeWriter::writeOperandBundles(const CallBase &CS,
2705                                               unsigned InstID) {
2706   SmallVector<unsigned, 64> Record;
2707   LLVMContext &C = CS.getContext();
2708 
2709   for (unsigned i = 0, e = CS.getNumOperandBundles(); i != e; ++i) {
2710     const auto &Bundle = CS.getOperandBundleAt(i);
2711     Record.push_back(C.getOperandBundleTagID(Bundle.getTagName()));
2712 
2713     for (auto &Input : Bundle.Inputs)
2714       pushValueAndType(Input, InstID, Record);
2715 
2716     Stream.EmitRecord(bitc::FUNC_CODE_OPERAND_BUNDLE, Record);
2717     Record.clear();
2718   }
2719 }
2720 
2721 /// pushValue - Like pushValueAndType, but where the type of the value is
2722 /// omitted (perhaps it was already encoded in an earlier operand).
2723 void ModuleBitcodeWriter::pushValue(const Value *V, unsigned InstID,
2724                                     SmallVectorImpl<unsigned> &Vals) {
2725   unsigned ValID = VE.getValueID(V);
2726   Vals.push_back(InstID - ValID);
2727 }
2728 
2729 void ModuleBitcodeWriter::pushValueSigned(const Value *V, unsigned InstID,
2730                                           SmallVectorImpl<uint64_t> &Vals) {
2731   unsigned ValID = VE.getValueID(V);
2732   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
2733   emitSignedInt64(Vals, diff);
2734 }
2735 
2736 /// WriteInstruction - Emit an instruction to the specified stream.
2737 void ModuleBitcodeWriter::writeInstruction(const Instruction &I,
2738                                            unsigned InstID,
2739                                            SmallVectorImpl<unsigned> &Vals) {
2740   unsigned Code = 0;
2741   unsigned AbbrevToUse = 0;
2742   VE.setInstructionID(&I);
2743   switch (I.getOpcode()) {
2744   default:
2745     if (Instruction::isCast(I.getOpcode())) {
2746       Code = bitc::FUNC_CODE_INST_CAST;
2747       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2748         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
2749       Vals.push_back(VE.getTypeID(I.getType()));
2750       Vals.push_back(getEncodedCastOpcode(I.getOpcode()));
2751     } else {
2752       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
2753       Code = bitc::FUNC_CODE_INST_BINOP;
2754       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2755         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
2756       pushValue(I.getOperand(1), InstID, Vals);
2757       Vals.push_back(getEncodedBinaryOpcode(I.getOpcode()));
2758       uint64_t Flags = getOptimizationFlags(&I);
2759       if (Flags != 0) {
2760         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
2761           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
2762         Vals.push_back(Flags);
2763       }
2764     }
2765     break;
2766   case Instruction::FNeg: {
2767     Code = bitc::FUNC_CODE_INST_UNOP;
2768     if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2769       AbbrevToUse = FUNCTION_INST_UNOP_ABBREV;
2770     Vals.push_back(getEncodedUnaryOpcode(I.getOpcode()));
2771     uint64_t Flags = getOptimizationFlags(&I);
2772     if (Flags != 0) {
2773       if (AbbrevToUse == FUNCTION_INST_UNOP_ABBREV)
2774         AbbrevToUse = FUNCTION_INST_UNOP_FLAGS_ABBREV;
2775       Vals.push_back(Flags);
2776     }
2777     break;
2778   }
2779   case Instruction::GetElementPtr: {
2780     Code = bitc::FUNC_CODE_INST_GEP;
2781     AbbrevToUse = FUNCTION_INST_GEP_ABBREV;
2782     auto &GEPInst = cast<GetElementPtrInst>(I);
2783     Vals.push_back(GEPInst.isInBounds());
2784     Vals.push_back(VE.getTypeID(GEPInst.getSourceElementType()));
2785     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
2786       pushValueAndType(I.getOperand(i), InstID, Vals);
2787     break;
2788   }
2789   case Instruction::ExtractValue: {
2790     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
2791     pushValueAndType(I.getOperand(0), InstID, Vals);
2792     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
2793     Vals.append(EVI->idx_begin(), EVI->idx_end());
2794     break;
2795   }
2796   case Instruction::InsertValue: {
2797     Code = bitc::FUNC_CODE_INST_INSERTVAL;
2798     pushValueAndType(I.getOperand(0), InstID, Vals);
2799     pushValueAndType(I.getOperand(1), InstID, Vals);
2800     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
2801     Vals.append(IVI->idx_begin(), IVI->idx_end());
2802     break;
2803   }
2804   case Instruction::Select: {
2805     Code = bitc::FUNC_CODE_INST_VSELECT;
2806     pushValueAndType(I.getOperand(1), InstID, Vals);
2807     pushValue(I.getOperand(2), InstID, Vals);
2808     pushValueAndType(I.getOperand(0), InstID, Vals);
2809     uint64_t Flags = getOptimizationFlags(&I);
2810     if (Flags != 0)
2811       Vals.push_back(Flags);
2812     break;
2813   }
2814   case Instruction::ExtractElement:
2815     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
2816     pushValueAndType(I.getOperand(0), InstID, Vals);
2817     pushValueAndType(I.getOperand(1), InstID, Vals);
2818     break;
2819   case Instruction::InsertElement:
2820     Code = bitc::FUNC_CODE_INST_INSERTELT;
2821     pushValueAndType(I.getOperand(0), InstID, Vals);
2822     pushValue(I.getOperand(1), InstID, Vals);
2823     pushValueAndType(I.getOperand(2), InstID, Vals);
2824     break;
2825   case Instruction::ShuffleVector:
2826     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
2827     pushValueAndType(I.getOperand(0), InstID, Vals);
2828     pushValue(I.getOperand(1), InstID, Vals);
2829     pushValue(cast<ShuffleVectorInst>(I).getShuffleMaskForBitcode(), InstID,
2830               Vals);
2831     break;
2832   case Instruction::ICmp:
2833   case Instruction::FCmp: {
2834     // compare returning Int1Ty or vector of Int1Ty
2835     Code = bitc::FUNC_CODE_INST_CMP2;
2836     pushValueAndType(I.getOperand(0), InstID, Vals);
2837     pushValue(I.getOperand(1), InstID, Vals);
2838     Vals.push_back(cast<CmpInst>(I).getPredicate());
2839     uint64_t Flags = getOptimizationFlags(&I);
2840     if (Flags != 0)
2841       Vals.push_back(Flags);
2842     break;
2843   }
2844 
2845   case Instruction::Ret:
2846     {
2847       Code = bitc::FUNC_CODE_INST_RET;
2848       unsigned NumOperands = I.getNumOperands();
2849       if (NumOperands == 0)
2850         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
2851       else if (NumOperands == 1) {
2852         if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2853           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
2854       } else {
2855         for (unsigned i = 0, e = NumOperands; i != e; ++i)
2856           pushValueAndType(I.getOperand(i), InstID, Vals);
2857       }
2858     }
2859     break;
2860   case Instruction::Br:
2861     {
2862       Code = bitc::FUNC_CODE_INST_BR;
2863       const BranchInst &II = cast<BranchInst>(I);
2864       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
2865       if (II.isConditional()) {
2866         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
2867         pushValue(II.getCondition(), InstID, Vals);
2868       }
2869     }
2870     break;
2871   case Instruction::Switch:
2872     {
2873       Code = bitc::FUNC_CODE_INST_SWITCH;
2874       const SwitchInst &SI = cast<SwitchInst>(I);
2875       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
2876       pushValue(SI.getCondition(), InstID, Vals);
2877       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
2878       for (auto Case : SI.cases()) {
2879         Vals.push_back(VE.getValueID(Case.getCaseValue()));
2880         Vals.push_back(VE.getValueID(Case.getCaseSuccessor()));
2881       }
2882     }
2883     break;
2884   case Instruction::IndirectBr:
2885     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
2886     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2887     // Encode the address operand as relative, but not the basic blocks.
2888     pushValue(I.getOperand(0), InstID, Vals);
2889     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
2890       Vals.push_back(VE.getValueID(I.getOperand(i)));
2891     break;
2892 
2893   case Instruction::Invoke: {
2894     const InvokeInst *II = cast<InvokeInst>(&I);
2895     const Value *Callee = II->getCalledOperand();
2896     FunctionType *FTy = II->getFunctionType();
2897 
2898     if (II->hasOperandBundles())
2899       writeOperandBundles(*II, InstID);
2900 
2901     Code = bitc::FUNC_CODE_INST_INVOKE;
2902 
2903     Vals.push_back(VE.getAttributeListID(II->getAttributes()));
2904     Vals.push_back(II->getCallingConv() | 1 << 13);
2905     Vals.push_back(VE.getValueID(II->getNormalDest()));
2906     Vals.push_back(VE.getValueID(II->getUnwindDest()));
2907     Vals.push_back(VE.getTypeID(FTy));
2908     pushValueAndType(Callee, InstID, Vals);
2909 
2910     // Emit value #'s for the fixed parameters.
2911     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
2912       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
2913 
2914     // Emit type/value pairs for varargs params.
2915     if (FTy->isVarArg()) {
2916       for (unsigned i = FTy->getNumParams(), e = II->getNumArgOperands();
2917            i != e; ++i)
2918         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
2919     }
2920     break;
2921   }
2922   case Instruction::Resume:
2923     Code = bitc::FUNC_CODE_INST_RESUME;
2924     pushValueAndType(I.getOperand(0), InstID, Vals);
2925     break;
2926   case Instruction::CleanupRet: {
2927     Code = bitc::FUNC_CODE_INST_CLEANUPRET;
2928     const auto &CRI = cast<CleanupReturnInst>(I);
2929     pushValue(CRI.getCleanupPad(), InstID, Vals);
2930     if (CRI.hasUnwindDest())
2931       Vals.push_back(VE.getValueID(CRI.getUnwindDest()));
2932     break;
2933   }
2934   case Instruction::CatchRet: {
2935     Code = bitc::FUNC_CODE_INST_CATCHRET;
2936     const auto &CRI = cast<CatchReturnInst>(I);
2937     pushValue(CRI.getCatchPad(), InstID, Vals);
2938     Vals.push_back(VE.getValueID(CRI.getSuccessor()));
2939     break;
2940   }
2941   case Instruction::CleanupPad:
2942   case Instruction::CatchPad: {
2943     const auto &FuncletPad = cast<FuncletPadInst>(I);
2944     Code = isa<CatchPadInst>(FuncletPad) ? bitc::FUNC_CODE_INST_CATCHPAD
2945                                          : bitc::FUNC_CODE_INST_CLEANUPPAD;
2946     pushValue(FuncletPad.getParentPad(), InstID, Vals);
2947 
2948     unsigned NumArgOperands = FuncletPad.getNumArgOperands();
2949     Vals.push_back(NumArgOperands);
2950     for (unsigned Op = 0; Op != NumArgOperands; ++Op)
2951       pushValueAndType(FuncletPad.getArgOperand(Op), InstID, Vals);
2952     break;
2953   }
2954   case Instruction::CatchSwitch: {
2955     Code = bitc::FUNC_CODE_INST_CATCHSWITCH;
2956     const auto &CatchSwitch = cast<CatchSwitchInst>(I);
2957 
2958     pushValue(CatchSwitch.getParentPad(), InstID, Vals);
2959 
2960     unsigned NumHandlers = CatchSwitch.getNumHandlers();
2961     Vals.push_back(NumHandlers);
2962     for (const BasicBlock *CatchPadBB : CatchSwitch.handlers())
2963       Vals.push_back(VE.getValueID(CatchPadBB));
2964 
2965     if (CatchSwitch.hasUnwindDest())
2966       Vals.push_back(VE.getValueID(CatchSwitch.getUnwindDest()));
2967     break;
2968   }
2969   case Instruction::CallBr: {
2970     const CallBrInst *CBI = cast<CallBrInst>(&I);
2971     const Value *Callee = CBI->getCalledOperand();
2972     FunctionType *FTy = CBI->getFunctionType();
2973 
2974     if (CBI->hasOperandBundles())
2975       writeOperandBundles(*CBI, InstID);
2976 
2977     Code = bitc::FUNC_CODE_INST_CALLBR;
2978 
2979     Vals.push_back(VE.getAttributeListID(CBI->getAttributes()));
2980 
2981     Vals.push_back(CBI->getCallingConv() << bitc::CALL_CCONV |
2982                    1 << bitc::CALL_EXPLICIT_TYPE);
2983 
2984     Vals.push_back(VE.getValueID(CBI->getDefaultDest()));
2985     Vals.push_back(CBI->getNumIndirectDests());
2986     for (unsigned i = 0, e = CBI->getNumIndirectDests(); i != e; ++i)
2987       Vals.push_back(VE.getValueID(CBI->getIndirectDest(i)));
2988 
2989     Vals.push_back(VE.getTypeID(FTy));
2990     pushValueAndType(Callee, InstID, Vals);
2991 
2992     // Emit value #'s for the fixed parameters.
2993     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
2994       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
2995 
2996     // Emit type/value pairs for varargs params.
2997     if (FTy->isVarArg()) {
2998       for (unsigned i = FTy->getNumParams(), e = CBI->getNumArgOperands();
2999            i != e; ++i)
3000         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
3001     }
3002     break;
3003   }
3004   case Instruction::Unreachable:
3005     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
3006     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
3007     break;
3008 
3009   case Instruction::PHI: {
3010     const PHINode &PN = cast<PHINode>(I);
3011     Code = bitc::FUNC_CODE_INST_PHI;
3012     // With the newer instruction encoding, forward references could give
3013     // negative valued IDs.  This is most common for PHIs, so we use
3014     // signed VBRs.
3015     SmallVector<uint64_t, 128> Vals64;
3016     Vals64.push_back(VE.getTypeID(PN.getType()));
3017     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
3018       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64);
3019       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
3020     }
3021 
3022     uint64_t Flags = getOptimizationFlags(&I);
3023     if (Flags != 0)
3024       Vals64.push_back(Flags);
3025 
3026     // Emit a Vals64 vector and exit.
3027     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
3028     Vals64.clear();
3029     return;
3030   }
3031 
3032   case Instruction::LandingPad: {
3033     const LandingPadInst &LP = cast<LandingPadInst>(I);
3034     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
3035     Vals.push_back(VE.getTypeID(LP.getType()));
3036     Vals.push_back(LP.isCleanup());
3037     Vals.push_back(LP.getNumClauses());
3038     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
3039       if (LP.isCatch(I))
3040         Vals.push_back(LandingPadInst::Catch);
3041       else
3042         Vals.push_back(LandingPadInst::Filter);
3043       pushValueAndType(LP.getClause(I), InstID, Vals);
3044     }
3045     break;
3046   }
3047 
3048   case Instruction::Alloca: {
3049     Code = bitc::FUNC_CODE_INST_ALLOCA;
3050     const AllocaInst &AI = cast<AllocaInst>(I);
3051     Vals.push_back(VE.getTypeID(AI.getAllocatedType()));
3052     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
3053     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
3054     using APV = AllocaPackedValues;
3055     unsigned Record = 0;
3056     Bitfield::set<APV::Align>(Record, getEncodedAlign(AI.getAlign()));
3057     Bitfield::set<APV::UsedWithInAlloca>(Record, AI.isUsedWithInAlloca());
3058     Bitfield::set<APV::ExplicitType>(Record, true);
3059     Bitfield::set<APV::SwiftError>(Record, AI.isSwiftError());
3060     Vals.push_back(Record);
3061     break;
3062   }
3063 
3064   case Instruction::Load:
3065     if (cast<LoadInst>(I).isAtomic()) {
3066       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
3067       pushValueAndType(I.getOperand(0), InstID, Vals);
3068     } else {
3069       Code = bitc::FUNC_CODE_INST_LOAD;
3070       if (!pushValueAndType(I.getOperand(0), InstID, Vals)) // ptr
3071         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
3072     }
3073     Vals.push_back(VE.getTypeID(I.getType()));
3074     Vals.push_back(getEncodedAlign(cast<LoadInst>(I).getAlign()));
3075     Vals.push_back(cast<LoadInst>(I).isVolatile());
3076     if (cast<LoadInst>(I).isAtomic()) {
3077       Vals.push_back(getEncodedOrdering(cast<LoadInst>(I).getOrdering()));
3078       Vals.push_back(getEncodedSyncScopeID(cast<LoadInst>(I).getSyncScopeID()));
3079     }
3080     break;
3081   case Instruction::Store:
3082     if (cast<StoreInst>(I).isAtomic())
3083       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
3084     else
3085       Code = bitc::FUNC_CODE_INST_STORE;
3086     pushValueAndType(I.getOperand(1), InstID, Vals); // ptrty + ptr
3087     pushValueAndType(I.getOperand(0), InstID, Vals); // valty + val
3088     Vals.push_back(getEncodedAlign(cast<StoreInst>(I).getAlign()));
3089     Vals.push_back(cast<StoreInst>(I).isVolatile());
3090     if (cast<StoreInst>(I).isAtomic()) {
3091       Vals.push_back(getEncodedOrdering(cast<StoreInst>(I).getOrdering()));
3092       Vals.push_back(
3093           getEncodedSyncScopeID(cast<StoreInst>(I).getSyncScopeID()));
3094     }
3095     break;
3096   case Instruction::AtomicCmpXchg:
3097     Code = bitc::FUNC_CODE_INST_CMPXCHG;
3098     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
3099     pushValueAndType(I.getOperand(1), InstID, Vals); // cmp.
3100     pushValue(I.getOperand(2), InstID, Vals);        // newval.
3101     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
3102     Vals.push_back(
3103         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
3104     Vals.push_back(
3105         getEncodedSyncScopeID(cast<AtomicCmpXchgInst>(I).getSyncScopeID()));
3106     Vals.push_back(
3107         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
3108     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
3109     Vals.push_back(getEncodedAlign(cast<AtomicCmpXchgInst>(I).getAlign()));
3110     break;
3111   case Instruction::AtomicRMW:
3112     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
3113     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
3114     pushValueAndType(I.getOperand(1), InstID, Vals); // valty + val
3115     Vals.push_back(
3116         getEncodedRMWOperation(cast<AtomicRMWInst>(I).getOperation()));
3117     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
3118     Vals.push_back(getEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
3119     Vals.push_back(
3120         getEncodedSyncScopeID(cast<AtomicRMWInst>(I).getSyncScopeID()));
3121     Vals.push_back(getEncodedAlign(cast<AtomicRMWInst>(I).getAlign()));
3122     break;
3123   case Instruction::Fence:
3124     Code = bitc::FUNC_CODE_INST_FENCE;
3125     Vals.push_back(getEncodedOrdering(cast<FenceInst>(I).getOrdering()));
3126     Vals.push_back(getEncodedSyncScopeID(cast<FenceInst>(I).getSyncScopeID()));
3127     break;
3128   case Instruction::Call: {
3129     const CallInst &CI = cast<CallInst>(I);
3130     FunctionType *FTy = CI.getFunctionType();
3131 
3132     if (CI.hasOperandBundles())
3133       writeOperandBundles(CI, InstID);
3134 
3135     Code = bitc::FUNC_CODE_INST_CALL;
3136 
3137     Vals.push_back(VE.getAttributeListID(CI.getAttributes()));
3138 
3139     unsigned Flags = getOptimizationFlags(&I);
3140     Vals.push_back(CI.getCallingConv() << bitc::CALL_CCONV |
3141                    unsigned(CI.isTailCall()) << bitc::CALL_TAIL |
3142                    unsigned(CI.isMustTailCall()) << bitc::CALL_MUSTTAIL |
3143                    1 << bitc::CALL_EXPLICIT_TYPE |
3144                    unsigned(CI.isNoTailCall()) << bitc::CALL_NOTAIL |
3145                    unsigned(Flags != 0) << bitc::CALL_FMF);
3146     if (Flags != 0)
3147       Vals.push_back(Flags);
3148 
3149     Vals.push_back(VE.getTypeID(FTy));
3150     pushValueAndType(CI.getCalledOperand(), InstID, Vals); // Callee
3151 
3152     // Emit value #'s for the fixed parameters.
3153     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
3154       // Check for labels (can happen with asm labels).
3155       if (FTy->getParamType(i)->isLabelTy())
3156         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
3157       else
3158         pushValue(CI.getArgOperand(i), InstID, Vals); // fixed param.
3159     }
3160 
3161     // Emit type/value pairs for varargs params.
3162     if (FTy->isVarArg()) {
3163       for (unsigned i = FTy->getNumParams(), e = CI.getNumArgOperands();
3164            i != e; ++i)
3165         pushValueAndType(CI.getArgOperand(i), InstID, Vals); // varargs
3166     }
3167     break;
3168   }
3169   case Instruction::VAArg:
3170     Code = bitc::FUNC_CODE_INST_VAARG;
3171     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
3172     pushValue(I.getOperand(0), InstID, Vals);                   // valist.
3173     Vals.push_back(VE.getTypeID(I.getType())); // restype.
3174     break;
3175   case Instruction::Freeze:
3176     Code = bitc::FUNC_CODE_INST_FREEZE;
3177     pushValueAndType(I.getOperand(0), InstID, Vals);
3178     break;
3179   }
3180 
3181   Stream.EmitRecord(Code, Vals, AbbrevToUse);
3182   Vals.clear();
3183 }
3184 
3185 /// Write a GlobalValue VST to the module. The purpose of this data structure is
3186 /// to allow clients to efficiently find the function body.
3187 void ModuleBitcodeWriter::writeGlobalValueSymbolTable(
3188   DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3189   // Get the offset of the VST we are writing, and backpatch it into
3190   // the VST forward declaration record.
3191   uint64_t VSTOffset = Stream.GetCurrentBitNo();
3192   // The BitcodeStartBit was the stream offset of the identification block.
3193   VSTOffset -= bitcodeStartBit();
3194   assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
3195   // Note that we add 1 here because the offset is relative to one word
3196   // before the start of the identification block, which was historically
3197   // always the start of the regular bitcode header.
3198   Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32 + 1);
3199 
3200   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3201 
3202   auto Abbv = std::make_shared<BitCodeAbbrev>();
3203   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
3204   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
3205   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
3206   unsigned FnEntryAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3207 
3208   for (const Function &F : M) {
3209     uint64_t Record[2];
3210 
3211     if (F.isDeclaration())
3212       continue;
3213 
3214     Record[0] = VE.getValueID(&F);
3215 
3216     // Save the word offset of the function (from the start of the
3217     // actual bitcode written to the stream).
3218     uint64_t BitcodeIndex = FunctionToBitcodeIndex[&F] - bitcodeStartBit();
3219     assert((BitcodeIndex & 31) == 0 && "function block not 32-bit aligned");
3220     // Note that we add 1 here because the offset is relative to one word
3221     // before the start of the identification block, which was historically
3222     // always the start of the regular bitcode header.
3223     Record[1] = BitcodeIndex / 32 + 1;
3224 
3225     Stream.EmitRecord(bitc::VST_CODE_FNENTRY, Record, FnEntryAbbrev);
3226   }
3227 
3228   Stream.ExitBlock();
3229 }
3230 
3231 /// Emit names for arguments, instructions and basic blocks in a function.
3232 void ModuleBitcodeWriter::writeFunctionLevelValueSymbolTable(
3233     const ValueSymbolTable &VST) {
3234   if (VST.empty())
3235     return;
3236 
3237   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3238 
3239   // FIXME: Set up the abbrev, we know how many values there are!
3240   // FIXME: We know if the type names can use 7-bit ascii.
3241   SmallVector<uint64_t, 64> NameVals;
3242 
3243   for (const ValueName &Name : VST) {
3244     // Figure out the encoding to use for the name.
3245     StringEncoding Bits = getStringEncoding(Name.getKey());
3246 
3247     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
3248     NameVals.push_back(VE.getValueID(Name.getValue()));
3249 
3250     // VST_CODE_ENTRY:   [valueid, namechar x N]
3251     // VST_CODE_BBENTRY: [bbid, namechar x N]
3252     unsigned Code;
3253     if (isa<BasicBlock>(Name.getValue())) {
3254       Code = bitc::VST_CODE_BBENTRY;
3255       if (Bits == SE_Char6)
3256         AbbrevToUse = VST_BBENTRY_6_ABBREV;
3257     } else {
3258       Code = bitc::VST_CODE_ENTRY;
3259       if (Bits == SE_Char6)
3260         AbbrevToUse = VST_ENTRY_6_ABBREV;
3261       else if (Bits == SE_Fixed7)
3262         AbbrevToUse = VST_ENTRY_7_ABBREV;
3263     }
3264 
3265     for (const auto P : Name.getKey())
3266       NameVals.push_back((unsigned char)P);
3267 
3268     // Emit the finished record.
3269     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
3270     NameVals.clear();
3271   }
3272 
3273   Stream.ExitBlock();
3274 }
3275 
3276 void ModuleBitcodeWriter::writeUseList(UseListOrder &&Order) {
3277   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
3278   unsigned Code;
3279   if (isa<BasicBlock>(Order.V))
3280     Code = bitc::USELIST_CODE_BB;
3281   else
3282     Code = bitc::USELIST_CODE_DEFAULT;
3283 
3284   SmallVector<uint64_t, 64> Record(Order.Shuffle.begin(), Order.Shuffle.end());
3285   Record.push_back(VE.getValueID(Order.V));
3286   Stream.EmitRecord(Code, Record);
3287 }
3288 
3289 void ModuleBitcodeWriter::writeUseListBlock(const Function *F) {
3290   assert(VE.shouldPreserveUseListOrder() &&
3291          "Expected to be preserving use-list order");
3292 
3293   auto hasMore = [&]() {
3294     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
3295   };
3296   if (!hasMore())
3297     // Nothing to do.
3298     return;
3299 
3300   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
3301   while (hasMore()) {
3302     writeUseList(std::move(VE.UseListOrders.back()));
3303     VE.UseListOrders.pop_back();
3304   }
3305   Stream.ExitBlock();
3306 }
3307 
3308 /// Emit a function body to the module stream.
3309 void ModuleBitcodeWriter::writeFunction(
3310     const Function &F,
3311     DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3312   // Save the bitcode index of the start of this function block for recording
3313   // in the VST.
3314   FunctionToBitcodeIndex[&F] = Stream.GetCurrentBitNo();
3315 
3316   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
3317   VE.incorporateFunction(F);
3318 
3319   SmallVector<unsigned, 64> Vals;
3320 
3321   // Emit the number of basic blocks, so the reader can create them ahead of
3322   // time.
3323   Vals.push_back(VE.getBasicBlocks().size());
3324   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
3325   Vals.clear();
3326 
3327   // If there are function-local constants, emit them now.
3328   unsigned CstStart, CstEnd;
3329   VE.getFunctionConstantRange(CstStart, CstEnd);
3330   writeConstants(CstStart, CstEnd, false);
3331 
3332   // If there is function-local metadata, emit it now.
3333   writeFunctionMetadata(F);
3334 
3335   // Keep a running idea of what the instruction ID is.
3336   unsigned InstID = CstEnd;
3337 
3338   bool NeedsMetadataAttachment = F.hasMetadata();
3339 
3340   DILocation *LastDL = nullptr;
3341   // Finally, emit all the instructions, in order.
3342   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
3343     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
3344          I != E; ++I) {
3345       writeInstruction(*I, InstID, Vals);
3346 
3347       if (!I->getType()->isVoidTy())
3348         ++InstID;
3349 
3350       // If the instruction has metadata, write a metadata attachment later.
3351       NeedsMetadataAttachment |= I->hasMetadataOtherThanDebugLoc();
3352 
3353       // If the instruction has a debug location, emit it.
3354       DILocation *DL = I->getDebugLoc();
3355       if (!DL)
3356         continue;
3357 
3358       if (DL == LastDL) {
3359         // Just repeat the same debug loc as last time.
3360         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
3361         continue;
3362       }
3363 
3364       Vals.push_back(DL->getLine());
3365       Vals.push_back(DL->getColumn());
3366       Vals.push_back(VE.getMetadataOrNullID(DL->getScope()));
3367       Vals.push_back(VE.getMetadataOrNullID(DL->getInlinedAt()));
3368       Vals.push_back(DL->isImplicitCode());
3369       Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
3370       Vals.clear();
3371 
3372       LastDL = DL;
3373     }
3374 
3375   // Emit names for all the instructions etc.
3376   if (auto *Symtab = F.getValueSymbolTable())
3377     writeFunctionLevelValueSymbolTable(*Symtab);
3378 
3379   if (NeedsMetadataAttachment)
3380     writeFunctionMetadataAttachment(F);
3381   if (VE.shouldPreserveUseListOrder())
3382     writeUseListBlock(&F);
3383   VE.purgeFunction();
3384   Stream.ExitBlock();
3385 }
3386 
3387 // Emit blockinfo, which defines the standard abbreviations etc.
3388 void ModuleBitcodeWriter::writeBlockInfo() {
3389   // We only want to emit block info records for blocks that have multiple
3390   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
3391   // Other blocks can define their abbrevs inline.
3392   Stream.EnterBlockInfoBlock();
3393 
3394   { // 8-bit fixed-width VST_CODE_ENTRY/VST_CODE_BBENTRY strings.
3395     auto Abbv = std::make_shared<BitCodeAbbrev>();
3396     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
3397     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3398     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3399     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3400     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3401         VST_ENTRY_8_ABBREV)
3402       llvm_unreachable("Unexpected abbrev ordering!");
3403   }
3404 
3405   { // 7-bit fixed width VST_CODE_ENTRY strings.
3406     auto Abbv = std::make_shared<BitCodeAbbrev>();
3407     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3408     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3409     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3410     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3411     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3412         VST_ENTRY_7_ABBREV)
3413       llvm_unreachable("Unexpected abbrev ordering!");
3414   }
3415   { // 6-bit char6 VST_CODE_ENTRY strings.
3416     auto Abbv = std::make_shared<BitCodeAbbrev>();
3417     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3418     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3419     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3420     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3421     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3422         VST_ENTRY_6_ABBREV)
3423       llvm_unreachable("Unexpected abbrev ordering!");
3424   }
3425   { // 6-bit char6 VST_CODE_BBENTRY strings.
3426     auto Abbv = std::make_shared<BitCodeAbbrev>();
3427     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
3428     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3429     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3430     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3431     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3432         VST_BBENTRY_6_ABBREV)
3433       llvm_unreachable("Unexpected abbrev ordering!");
3434   }
3435 
3436   { // SETTYPE abbrev for CONSTANTS_BLOCK.
3437     auto Abbv = std::make_shared<BitCodeAbbrev>();
3438     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
3439     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
3440                               VE.computeBitsRequiredForTypeIndicies()));
3441     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3442         CONSTANTS_SETTYPE_ABBREV)
3443       llvm_unreachable("Unexpected abbrev ordering!");
3444   }
3445 
3446   { // INTEGER abbrev for CONSTANTS_BLOCK.
3447     auto Abbv = std::make_shared<BitCodeAbbrev>();
3448     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
3449     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3450     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3451         CONSTANTS_INTEGER_ABBREV)
3452       llvm_unreachable("Unexpected abbrev ordering!");
3453   }
3454 
3455   { // CE_CAST abbrev for CONSTANTS_BLOCK.
3456     auto Abbv = std::make_shared<BitCodeAbbrev>();
3457     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
3458     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
3459     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
3460                               VE.computeBitsRequiredForTypeIndicies()));
3461     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
3462 
3463     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3464         CONSTANTS_CE_CAST_Abbrev)
3465       llvm_unreachable("Unexpected abbrev ordering!");
3466   }
3467   { // NULL abbrev for CONSTANTS_BLOCK.
3468     auto Abbv = std::make_shared<BitCodeAbbrev>();
3469     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
3470     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3471         CONSTANTS_NULL_Abbrev)
3472       llvm_unreachable("Unexpected abbrev ordering!");
3473   }
3474 
3475   // FIXME: This should only use space for first class types!
3476 
3477   { // INST_LOAD abbrev for FUNCTION_BLOCK.
3478     auto Abbv = std::make_shared<BitCodeAbbrev>();
3479     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
3480     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
3481     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
3482                               VE.computeBitsRequiredForTypeIndicies()));
3483     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
3484     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
3485     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3486         FUNCTION_INST_LOAD_ABBREV)
3487       llvm_unreachable("Unexpected abbrev ordering!");
3488   }
3489   { // INST_UNOP abbrev for FUNCTION_BLOCK.
3490     auto Abbv = std::make_shared<BitCodeAbbrev>();
3491     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3492     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3493     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3494     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3495         FUNCTION_INST_UNOP_ABBREV)
3496       llvm_unreachable("Unexpected abbrev ordering!");
3497   }
3498   { // INST_UNOP_FLAGS abbrev for FUNCTION_BLOCK.
3499     auto Abbv = std::make_shared<BitCodeAbbrev>();
3500     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3501     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3502     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3503     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3504     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3505         FUNCTION_INST_UNOP_FLAGS_ABBREV)
3506       llvm_unreachable("Unexpected abbrev ordering!");
3507   }
3508   { // INST_BINOP abbrev for FUNCTION_BLOCK.
3509     auto Abbv = std::make_shared<BitCodeAbbrev>();
3510     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3511     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3512     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3513     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3514     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3515         FUNCTION_INST_BINOP_ABBREV)
3516       llvm_unreachable("Unexpected abbrev ordering!");
3517   }
3518   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
3519     auto Abbv = std::make_shared<BitCodeAbbrev>();
3520     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3521     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3522     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3523     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3524     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3525     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3526         FUNCTION_INST_BINOP_FLAGS_ABBREV)
3527       llvm_unreachable("Unexpected abbrev ordering!");
3528   }
3529   { // INST_CAST abbrev for FUNCTION_BLOCK.
3530     auto Abbv = std::make_shared<BitCodeAbbrev>();
3531     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
3532     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
3533     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
3534                               VE.computeBitsRequiredForTypeIndicies()));
3535     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
3536     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3537         FUNCTION_INST_CAST_ABBREV)
3538       llvm_unreachable("Unexpected abbrev ordering!");
3539   }
3540 
3541   { // INST_RET abbrev for FUNCTION_BLOCK.
3542     auto Abbv = std::make_shared<BitCodeAbbrev>();
3543     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3544     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3545         FUNCTION_INST_RET_VOID_ABBREV)
3546       llvm_unreachable("Unexpected abbrev ordering!");
3547   }
3548   { // INST_RET abbrev for FUNCTION_BLOCK.
3549     auto Abbv = std::make_shared<BitCodeAbbrev>();
3550     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3551     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
3552     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3553         FUNCTION_INST_RET_VAL_ABBREV)
3554       llvm_unreachable("Unexpected abbrev ordering!");
3555   }
3556   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
3557     auto Abbv = std::make_shared<BitCodeAbbrev>();
3558     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
3559     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3560         FUNCTION_INST_UNREACHABLE_ABBREV)
3561       llvm_unreachable("Unexpected abbrev ordering!");
3562   }
3563   {
3564     auto Abbv = std::make_shared<BitCodeAbbrev>();
3565     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_GEP));
3566     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
3567     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, // dest ty
3568                               Log2_32_Ceil(VE.getTypes().size() + 1)));
3569     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3570     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
3571     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3572         FUNCTION_INST_GEP_ABBREV)
3573       llvm_unreachable("Unexpected abbrev ordering!");
3574   }
3575 
3576   Stream.ExitBlock();
3577 }
3578 
3579 /// Write the module path strings, currently only used when generating
3580 /// a combined index file.
3581 void IndexBitcodeWriter::writeModStrings() {
3582   Stream.EnterSubblock(bitc::MODULE_STRTAB_BLOCK_ID, 3);
3583 
3584   // TODO: See which abbrev sizes we actually need to emit
3585 
3586   // 8-bit fixed-width MST_ENTRY strings.
3587   auto Abbv = std::make_shared<BitCodeAbbrev>();
3588   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3589   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3590   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3591   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3592   unsigned Abbrev8Bit = Stream.EmitAbbrev(std::move(Abbv));
3593 
3594   // 7-bit fixed width MST_ENTRY strings.
3595   Abbv = std::make_shared<BitCodeAbbrev>();
3596   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3597   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3598   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3599   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3600   unsigned Abbrev7Bit = Stream.EmitAbbrev(std::move(Abbv));
3601 
3602   // 6-bit char6 MST_ENTRY strings.
3603   Abbv = std::make_shared<BitCodeAbbrev>();
3604   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3605   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3606   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3607   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3608   unsigned Abbrev6Bit = Stream.EmitAbbrev(std::move(Abbv));
3609 
3610   // Module Hash, 160 bits SHA1. Optionally, emitted after each MST_CODE_ENTRY.
3611   Abbv = std::make_shared<BitCodeAbbrev>();
3612   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_HASH));
3613   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3614   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3615   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3616   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3617   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3618   unsigned AbbrevHash = Stream.EmitAbbrev(std::move(Abbv));
3619 
3620   SmallVector<unsigned, 64> Vals;
3621   forEachModule(
3622       [&](const StringMapEntry<std::pair<uint64_t, ModuleHash>> &MPSE) {
3623         StringRef Key = MPSE.getKey();
3624         const auto &Value = MPSE.getValue();
3625         StringEncoding Bits = getStringEncoding(Key);
3626         unsigned AbbrevToUse = Abbrev8Bit;
3627         if (Bits == SE_Char6)
3628           AbbrevToUse = Abbrev6Bit;
3629         else if (Bits == SE_Fixed7)
3630           AbbrevToUse = Abbrev7Bit;
3631 
3632         Vals.push_back(Value.first);
3633         Vals.append(Key.begin(), Key.end());
3634 
3635         // Emit the finished record.
3636         Stream.EmitRecord(bitc::MST_CODE_ENTRY, Vals, AbbrevToUse);
3637 
3638         // Emit an optional hash for the module now
3639         const auto &Hash = Value.second;
3640         if (llvm::any_of(Hash, [](uint32_t H) { return H; })) {
3641           Vals.assign(Hash.begin(), Hash.end());
3642           // Emit the hash record.
3643           Stream.EmitRecord(bitc::MST_CODE_HASH, Vals, AbbrevHash);
3644         }
3645 
3646         Vals.clear();
3647       });
3648   Stream.ExitBlock();
3649 }
3650 
3651 /// Write the function type metadata related records that need to appear before
3652 /// a function summary entry (whether per-module or combined).
3653 template <typename Fn>
3654 static void writeFunctionTypeMetadataRecords(BitstreamWriter &Stream,
3655                                              FunctionSummary *FS,
3656                                              Fn GetValueID) {
3657   if (!FS->type_tests().empty())
3658     Stream.EmitRecord(bitc::FS_TYPE_TESTS, FS->type_tests());
3659 
3660   SmallVector<uint64_t, 64> Record;
3661 
3662   auto WriteVFuncIdVec = [&](uint64_t Ty,
3663                              ArrayRef<FunctionSummary::VFuncId> VFs) {
3664     if (VFs.empty())
3665       return;
3666     Record.clear();
3667     for (auto &VF : VFs) {
3668       Record.push_back(VF.GUID);
3669       Record.push_back(VF.Offset);
3670     }
3671     Stream.EmitRecord(Ty, Record);
3672   };
3673 
3674   WriteVFuncIdVec(bitc::FS_TYPE_TEST_ASSUME_VCALLS,
3675                   FS->type_test_assume_vcalls());
3676   WriteVFuncIdVec(bitc::FS_TYPE_CHECKED_LOAD_VCALLS,
3677                   FS->type_checked_load_vcalls());
3678 
3679   auto WriteConstVCallVec = [&](uint64_t Ty,
3680                                 ArrayRef<FunctionSummary::ConstVCall> VCs) {
3681     for (auto &VC : VCs) {
3682       Record.clear();
3683       Record.push_back(VC.VFunc.GUID);
3684       Record.push_back(VC.VFunc.Offset);
3685       llvm::append_range(Record, VC.Args);
3686       Stream.EmitRecord(Ty, Record);
3687     }
3688   };
3689 
3690   WriteConstVCallVec(bitc::FS_TYPE_TEST_ASSUME_CONST_VCALL,
3691                      FS->type_test_assume_const_vcalls());
3692   WriteConstVCallVec(bitc::FS_TYPE_CHECKED_LOAD_CONST_VCALL,
3693                      FS->type_checked_load_const_vcalls());
3694 
3695   auto WriteRange = [&](ConstantRange Range) {
3696     Range = Range.sextOrTrunc(FunctionSummary::ParamAccess::RangeWidth);
3697     assert(Range.getLower().getNumWords() == 1);
3698     assert(Range.getUpper().getNumWords() == 1);
3699     emitSignedInt64(Record, *Range.getLower().getRawData());
3700     emitSignedInt64(Record, *Range.getUpper().getRawData());
3701   };
3702 
3703   if (!FS->paramAccesses().empty()) {
3704     Record.clear();
3705     for (auto &Arg : FS->paramAccesses()) {
3706       size_t UndoSize = Record.size();
3707       Record.push_back(Arg.ParamNo);
3708       WriteRange(Arg.Use);
3709       Record.push_back(Arg.Calls.size());
3710       for (auto &Call : Arg.Calls) {
3711         Record.push_back(Call.ParamNo);
3712         Optional<unsigned> ValueID = GetValueID(Call.Callee);
3713         if (!ValueID) {
3714           // If ValueID is unknown we can't drop just this call, we must drop
3715           // entire parameter.
3716           Record.resize(UndoSize);
3717           break;
3718         }
3719         Record.push_back(*ValueID);
3720         WriteRange(Call.Offsets);
3721       }
3722     }
3723     if (!Record.empty())
3724       Stream.EmitRecord(bitc::FS_PARAM_ACCESS, Record);
3725   }
3726 }
3727 
3728 /// Collect type IDs from type tests used by function.
3729 static void
3730 getReferencedTypeIds(FunctionSummary *FS,
3731                      std::set<GlobalValue::GUID> &ReferencedTypeIds) {
3732   if (!FS->type_tests().empty())
3733     for (auto &TT : FS->type_tests())
3734       ReferencedTypeIds.insert(TT);
3735 
3736   auto GetReferencedTypesFromVFuncIdVec =
3737       [&](ArrayRef<FunctionSummary::VFuncId> VFs) {
3738         for (auto &VF : VFs)
3739           ReferencedTypeIds.insert(VF.GUID);
3740       };
3741 
3742   GetReferencedTypesFromVFuncIdVec(FS->type_test_assume_vcalls());
3743   GetReferencedTypesFromVFuncIdVec(FS->type_checked_load_vcalls());
3744 
3745   auto GetReferencedTypesFromConstVCallVec =
3746       [&](ArrayRef<FunctionSummary::ConstVCall> VCs) {
3747         for (auto &VC : VCs)
3748           ReferencedTypeIds.insert(VC.VFunc.GUID);
3749       };
3750 
3751   GetReferencedTypesFromConstVCallVec(FS->type_test_assume_const_vcalls());
3752   GetReferencedTypesFromConstVCallVec(FS->type_checked_load_const_vcalls());
3753 }
3754 
3755 static void writeWholeProgramDevirtResolutionByArg(
3756     SmallVector<uint64_t, 64> &NameVals, const std::vector<uint64_t> &args,
3757     const WholeProgramDevirtResolution::ByArg &ByArg) {
3758   NameVals.push_back(args.size());
3759   llvm::append_range(NameVals, args);
3760 
3761   NameVals.push_back(ByArg.TheKind);
3762   NameVals.push_back(ByArg.Info);
3763   NameVals.push_back(ByArg.Byte);
3764   NameVals.push_back(ByArg.Bit);
3765 }
3766 
3767 static void writeWholeProgramDevirtResolution(
3768     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3769     uint64_t Id, const WholeProgramDevirtResolution &Wpd) {
3770   NameVals.push_back(Id);
3771 
3772   NameVals.push_back(Wpd.TheKind);
3773   NameVals.push_back(StrtabBuilder.add(Wpd.SingleImplName));
3774   NameVals.push_back(Wpd.SingleImplName.size());
3775 
3776   NameVals.push_back(Wpd.ResByArg.size());
3777   for (auto &A : Wpd.ResByArg)
3778     writeWholeProgramDevirtResolutionByArg(NameVals, A.first, A.second);
3779 }
3780 
3781 static void writeTypeIdSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
3782                                      StringTableBuilder &StrtabBuilder,
3783                                      const std::string &Id,
3784                                      const TypeIdSummary &Summary) {
3785   NameVals.push_back(StrtabBuilder.add(Id));
3786   NameVals.push_back(Id.size());
3787 
3788   NameVals.push_back(Summary.TTRes.TheKind);
3789   NameVals.push_back(Summary.TTRes.SizeM1BitWidth);
3790   NameVals.push_back(Summary.TTRes.AlignLog2);
3791   NameVals.push_back(Summary.TTRes.SizeM1);
3792   NameVals.push_back(Summary.TTRes.BitMask);
3793   NameVals.push_back(Summary.TTRes.InlineBits);
3794 
3795   for (auto &W : Summary.WPDRes)
3796     writeWholeProgramDevirtResolution(NameVals, StrtabBuilder, W.first,
3797                                       W.second);
3798 }
3799 
3800 static void writeTypeIdCompatibleVtableSummaryRecord(
3801     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3802     const std::string &Id, const TypeIdCompatibleVtableInfo &Summary,
3803     ValueEnumerator &VE) {
3804   NameVals.push_back(StrtabBuilder.add(Id));
3805   NameVals.push_back(Id.size());
3806 
3807   for (auto &P : Summary) {
3808     NameVals.push_back(P.AddressPointOffset);
3809     NameVals.push_back(VE.getValueID(P.VTableVI.getValue()));
3810   }
3811 }
3812 
3813 // Helper to emit a single function summary record.
3814 void ModuleBitcodeWriterBase::writePerModuleFunctionSummaryRecord(
3815     SmallVector<uint64_t, 64> &NameVals, GlobalValueSummary *Summary,
3816     unsigned ValueID, unsigned FSCallsAbbrev, unsigned FSCallsProfileAbbrev,
3817     const Function &F) {
3818   NameVals.push_back(ValueID);
3819 
3820   FunctionSummary *FS = cast<FunctionSummary>(Summary);
3821 
3822   writeFunctionTypeMetadataRecords(
3823       Stream, FS, [&](const ValueInfo &VI) -> Optional<unsigned> {
3824         return {VE.getValueID(VI.getValue())};
3825       });
3826 
3827   auto SpecialRefCnts = FS->specialRefCounts();
3828   NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
3829   NameVals.push_back(FS->instCount());
3830   NameVals.push_back(getEncodedFFlags(FS->fflags()));
3831   NameVals.push_back(FS->refs().size());
3832   NameVals.push_back(SpecialRefCnts.first);  // rorefcnt
3833   NameVals.push_back(SpecialRefCnts.second); // worefcnt
3834 
3835   for (auto &RI : FS->refs())
3836     NameVals.push_back(VE.getValueID(RI.getValue()));
3837 
3838   bool HasProfileData =
3839       F.hasProfileData() || ForceSummaryEdgesCold != FunctionSummary::FSHT_None;
3840   for (auto &ECI : FS->calls()) {
3841     NameVals.push_back(getValueId(ECI.first));
3842     if (HasProfileData)
3843       NameVals.push_back(static_cast<uint8_t>(ECI.second.Hotness));
3844     else if (WriteRelBFToSummary)
3845       NameVals.push_back(ECI.second.RelBlockFreq);
3846   }
3847 
3848   unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
3849   unsigned Code =
3850       (HasProfileData ? bitc::FS_PERMODULE_PROFILE
3851                       : (WriteRelBFToSummary ? bitc::FS_PERMODULE_RELBF
3852                                              : bitc::FS_PERMODULE));
3853 
3854   // Emit the finished record.
3855   Stream.EmitRecord(Code, NameVals, FSAbbrev);
3856   NameVals.clear();
3857 }
3858 
3859 // Collect the global value references in the given variable's initializer,
3860 // and emit them in a summary record.
3861 void ModuleBitcodeWriterBase::writeModuleLevelReferences(
3862     const GlobalVariable &V, SmallVector<uint64_t, 64> &NameVals,
3863     unsigned FSModRefsAbbrev, unsigned FSModVTableRefsAbbrev) {
3864   auto VI = Index->getValueInfo(V.getGUID());
3865   if (!VI || VI.getSummaryList().empty()) {
3866     // Only declarations should not have a summary (a declaration might however
3867     // have a summary if the def was in module level asm).
3868     assert(V.isDeclaration());
3869     return;
3870   }
3871   auto *Summary = VI.getSummaryList()[0].get();
3872   NameVals.push_back(VE.getValueID(&V));
3873   GlobalVarSummary *VS = cast<GlobalVarSummary>(Summary);
3874   NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
3875   NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
3876 
3877   auto VTableFuncs = VS->vTableFuncs();
3878   if (!VTableFuncs.empty())
3879     NameVals.push_back(VS->refs().size());
3880 
3881   unsigned SizeBeforeRefs = NameVals.size();
3882   for (auto &RI : VS->refs())
3883     NameVals.push_back(VE.getValueID(RI.getValue()));
3884   // Sort the refs for determinism output, the vector returned by FS->refs() has
3885   // been initialized from a DenseSet.
3886   llvm::sort(drop_begin(NameVals, SizeBeforeRefs));
3887 
3888   if (VTableFuncs.empty())
3889     Stream.EmitRecord(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS, NameVals,
3890                       FSModRefsAbbrev);
3891   else {
3892     // VTableFuncs pairs should already be sorted by offset.
3893     for (auto &P : VTableFuncs) {
3894       NameVals.push_back(VE.getValueID(P.FuncVI.getValue()));
3895       NameVals.push_back(P.VTableOffset);
3896     }
3897 
3898     Stream.EmitRecord(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS, NameVals,
3899                       FSModVTableRefsAbbrev);
3900   }
3901   NameVals.clear();
3902 }
3903 
3904 /// Emit the per-module summary section alongside the rest of
3905 /// the module's bitcode.
3906 void ModuleBitcodeWriterBase::writePerModuleGlobalValueSummary() {
3907   // By default we compile with ThinLTO if the module has a summary, but the
3908   // client can request full LTO with a module flag.
3909   bool IsThinLTO = true;
3910   if (auto *MD =
3911           mdconst::extract_or_null<ConstantInt>(M.getModuleFlag("ThinLTO")))
3912     IsThinLTO = MD->getZExtValue();
3913   Stream.EnterSubblock(IsThinLTO ? bitc::GLOBALVAL_SUMMARY_BLOCK_ID
3914                                  : bitc::FULL_LTO_GLOBALVAL_SUMMARY_BLOCK_ID,
3915                        4);
3916 
3917   Stream.EmitRecord(
3918       bitc::FS_VERSION,
3919       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
3920 
3921   // Write the index flags.
3922   uint64_t Flags = 0;
3923   // Bits 1-3 are set only in the combined index, skip them.
3924   if (Index->enableSplitLTOUnit())
3925     Flags |= 0x8;
3926   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Flags});
3927 
3928   if (Index->begin() == Index->end()) {
3929     Stream.ExitBlock();
3930     return;
3931   }
3932 
3933   for (const auto &GVI : valueIds()) {
3934     Stream.EmitRecord(bitc::FS_VALUE_GUID,
3935                       ArrayRef<uint64_t>{GVI.second, GVI.first});
3936   }
3937 
3938   // Abbrev for FS_PERMODULE_PROFILE.
3939   auto Abbv = std::make_shared<BitCodeAbbrev>();
3940   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_PROFILE));
3941   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3942   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3943   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3944   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3945   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3946   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
3947   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
3948   // numrefs x valueid, n x (valueid, hotness)
3949   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3950   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3951   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3952 
3953   // Abbrev for FS_PERMODULE or FS_PERMODULE_RELBF.
3954   Abbv = std::make_shared<BitCodeAbbrev>();
3955   if (WriteRelBFToSummary)
3956     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_RELBF));
3957   else
3958     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE));
3959   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3960   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3961   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3962   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3963   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3964   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
3965   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
3966   // numrefs x valueid, n x (valueid [, rel_block_freq])
3967   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3968   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3969   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3970 
3971   // Abbrev for FS_PERMODULE_GLOBALVAR_INIT_REFS.
3972   Abbv = std::make_shared<BitCodeAbbrev>();
3973   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS));
3974   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
3975   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
3976   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));  // valueids
3977   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3978   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3979 
3980   // Abbrev for FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS.
3981   Abbv = std::make_shared<BitCodeAbbrev>();
3982   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS));
3983   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
3984   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
3985   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numrefs
3986   // numrefs x valueid, n x (valueid , offset)
3987   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3988   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3989   unsigned FSModVTableRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3990 
3991   // Abbrev for FS_ALIAS.
3992   Abbv = std::make_shared<BitCodeAbbrev>();
3993   Abbv->Add(BitCodeAbbrevOp(bitc::FS_ALIAS));
3994   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3995   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3996   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3997   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3998 
3999   // Abbrev for FS_TYPE_ID_METADATA
4000   Abbv = std::make_shared<BitCodeAbbrev>();
4001   Abbv->Add(BitCodeAbbrevOp(bitc::FS_TYPE_ID_METADATA));
4002   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid strtab index
4003   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid length
4004   // n x (valueid , offset)
4005   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4006   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4007   unsigned TypeIdCompatibleVtableAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4008 
4009   SmallVector<uint64_t, 64> NameVals;
4010   // Iterate over the list of functions instead of the Index to
4011   // ensure the ordering is stable.
4012   for (const Function &F : M) {
4013     // Summary emission does not support anonymous functions, they have to
4014     // renamed using the anonymous function renaming pass.
4015     if (!F.hasName())
4016       report_fatal_error("Unexpected anonymous function when writing summary");
4017 
4018     ValueInfo VI = Index->getValueInfo(F.getGUID());
4019     if (!VI || VI.getSummaryList().empty()) {
4020       // Only declarations should not have a summary (a declaration might
4021       // however have a summary if the def was in module level asm).
4022       assert(F.isDeclaration());
4023       continue;
4024     }
4025     auto *Summary = VI.getSummaryList()[0].get();
4026     writePerModuleFunctionSummaryRecord(NameVals, Summary, VE.getValueID(&F),
4027                                         FSCallsAbbrev, FSCallsProfileAbbrev, F);
4028   }
4029 
4030   // Capture references from GlobalVariable initializers, which are outside
4031   // of a function scope.
4032   for (const GlobalVariable &G : M.globals())
4033     writeModuleLevelReferences(G, NameVals, FSModRefsAbbrev,
4034                                FSModVTableRefsAbbrev);
4035 
4036   for (const GlobalAlias &A : M.aliases()) {
4037     auto *Aliasee = A.getBaseObject();
4038     if (!Aliasee->hasName())
4039       // Nameless function don't have an entry in the summary, skip it.
4040       continue;
4041     auto AliasId = VE.getValueID(&A);
4042     auto AliaseeId = VE.getValueID(Aliasee);
4043     NameVals.push_back(AliasId);
4044     auto *Summary = Index->getGlobalValueSummary(A);
4045     AliasSummary *AS = cast<AliasSummary>(Summary);
4046     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
4047     NameVals.push_back(AliaseeId);
4048     Stream.EmitRecord(bitc::FS_ALIAS, NameVals, FSAliasAbbrev);
4049     NameVals.clear();
4050   }
4051 
4052   for (auto &S : Index->typeIdCompatibleVtableMap()) {
4053     writeTypeIdCompatibleVtableSummaryRecord(NameVals, StrtabBuilder, S.first,
4054                                              S.second, VE);
4055     Stream.EmitRecord(bitc::FS_TYPE_ID_METADATA, NameVals,
4056                       TypeIdCompatibleVtableAbbrev);
4057     NameVals.clear();
4058   }
4059 
4060   Stream.EmitRecord(bitc::FS_BLOCK_COUNT,
4061                     ArrayRef<uint64_t>{Index->getBlockCount()});
4062 
4063   Stream.ExitBlock();
4064 }
4065 
4066 /// Emit the combined summary section into the combined index file.
4067 void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
4068   Stream.EnterSubblock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID, 3);
4069   Stream.EmitRecord(
4070       bitc::FS_VERSION,
4071       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
4072 
4073   // Write the index flags.
4074   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Index.getFlags()});
4075 
4076   for (const auto &GVI : valueIds()) {
4077     Stream.EmitRecord(bitc::FS_VALUE_GUID,
4078                       ArrayRef<uint64_t>{GVI.second, GVI.first});
4079   }
4080 
4081   // Abbrev for FS_COMBINED.
4082   auto Abbv = std::make_shared<BitCodeAbbrev>();
4083   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED));
4084   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4085   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4086   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4087   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4088   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4089   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
4090   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4091   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4092   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4093   // numrefs x valueid, n x (valueid)
4094   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4095   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4096   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4097 
4098   // Abbrev for FS_COMBINED_PROFILE.
4099   Abbv = std::make_shared<BitCodeAbbrev>();
4100   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_PROFILE));
4101   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4102   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4103   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4104   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4105   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4106   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
4107   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4108   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4109   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4110   // numrefs x valueid, n x (valueid, hotness)
4111   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4112   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4113   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4114 
4115   // Abbrev for FS_COMBINED_GLOBALVAR_INIT_REFS.
4116   Abbv = std::make_shared<BitCodeAbbrev>();
4117   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS));
4118   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4119   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4120   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4121   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));    // valueids
4122   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4123   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4124 
4125   // Abbrev for FS_COMBINED_ALIAS.
4126   Abbv = std::make_shared<BitCodeAbbrev>();
4127   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_ALIAS));
4128   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4129   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4130   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4131   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4132   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4133 
4134   // The aliases are emitted as a post-pass, and will point to the value
4135   // id of the aliasee. Save them in a vector for post-processing.
4136   SmallVector<AliasSummary *, 64> Aliases;
4137 
4138   // Save the value id for each summary for alias emission.
4139   DenseMap<const GlobalValueSummary *, unsigned> SummaryToValueIdMap;
4140 
4141   SmallVector<uint64_t, 64> NameVals;
4142 
4143   // Set that will be populated during call to writeFunctionTypeMetadataRecords
4144   // with the type ids referenced by this index file.
4145   std::set<GlobalValue::GUID> ReferencedTypeIds;
4146 
4147   // For local linkage, we also emit the original name separately
4148   // immediately after the record.
4149   auto MaybeEmitOriginalName = [&](GlobalValueSummary &S) {
4150     if (!GlobalValue::isLocalLinkage(S.linkage()))
4151       return;
4152     NameVals.push_back(S.getOriginalName());
4153     Stream.EmitRecord(bitc::FS_COMBINED_ORIGINAL_NAME, NameVals);
4154     NameVals.clear();
4155   };
4156 
4157   std::set<GlobalValue::GUID> DefOrUseGUIDs;
4158   forEachSummary([&](GVInfo I, bool IsAliasee) {
4159     GlobalValueSummary *S = I.second;
4160     assert(S);
4161     DefOrUseGUIDs.insert(I.first);
4162     for (const ValueInfo &VI : S->refs())
4163       DefOrUseGUIDs.insert(VI.getGUID());
4164 
4165     auto ValueId = getValueId(I.first);
4166     assert(ValueId);
4167     SummaryToValueIdMap[S] = *ValueId;
4168 
4169     // If this is invoked for an aliasee, we want to record the above
4170     // mapping, but then not emit a summary entry (if the aliasee is
4171     // to be imported, we will invoke this separately with IsAliasee=false).
4172     if (IsAliasee)
4173       return;
4174 
4175     if (auto *AS = dyn_cast<AliasSummary>(S)) {
4176       // Will process aliases as a post-pass because the reader wants all
4177       // global to be loaded first.
4178       Aliases.push_back(AS);
4179       return;
4180     }
4181 
4182     if (auto *VS = dyn_cast<GlobalVarSummary>(S)) {
4183       NameVals.push_back(*ValueId);
4184       NameVals.push_back(Index.getModuleId(VS->modulePath()));
4185       NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
4186       NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
4187       for (auto &RI : VS->refs()) {
4188         auto RefValueId = getValueId(RI.getGUID());
4189         if (!RefValueId)
4190           continue;
4191         NameVals.push_back(*RefValueId);
4192       }
4193 
4194       // Emit the finished record.
4195       Stream.EmitRecord(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS, NameVals,
4196                         FSModRefsAbbrev);
4197       NameVals.clear();
4198       MaybeEmitOriginalName(*S);
4199       return;
4200     }
4201 
4202     auto GetValueId = [&](const ValueInfo &VI) -> Optional<unsigned> {
4203       GlobalValue::GUID GUID = VI.getGUID();
4204       Optional<unsigned> CallValueId = getValueId(GUID);
4205       if (CallValueId)
4206         return CallValueId;
4207       // For SamplePGO, the indirect call targets for local functions will
4208       // have its original name annotated in profile. We try to find the
4209       // corresponding PGOFuncName as the GUID.
4210       GUID = Index.getGUIDFromOriginalID(GUID);
4211       if (!GUID)
4212         return None;
4213       CallValueId = getValueId(GUID);
4214       if (!CallValueId)
4215         return None;
4216       // The mapping from OriginalId to GUID may return a GUID
4217       // that corresponds to a static variable. Filter it out here.
4218       // This can happen when
4219       // 1) There is a call to a library function which does not have
4220       // a CallValidId;
4221       // 2) There is a static variable with the  OriginalGUID identical
4222       // to the GUID of the library function in 1);
4223       // When this happens, the logic for SamplePGO kicks in and
4224       // the static variable in 2) will be found, which needs to be
4225       // filtered out.
4226       auto *GVSum = Index.getGlobalValueSummary(GUID, false);
4227       if (GVSum && GVSum->getSummaryKind() == GlobalValueSummary::GlobalVarKind)
4228         return None;
4229       return CallValueId;
4230     };
4231 
4232     auto *FS = cast<FunctionSummary>(S);
4233     writeFunctionTypeMetadataRecords(Stream, FS, GetValueId);
4234     getReferencedTypeIds(FS, ReferencedTypeIds);
4235 
4236     NameVals.push_back(*ValueId);
4237     NameVals.push_back(Index.getModuleId(FS->modulePath()));
4238     NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
4239     NameVals.push_back(FS->instCount());
4240     NameVals.push_back(getEncodedFFlags(FS->fflags()));
4241     NameVals.push_back(FS->entryCount());
4242 
4243     // Fill in below
4244     NameVals.push_back(0); // numrefs
4245     NameVals.push_back(0); // rorefcnt
4246     NameVals.push_back(0); // worefcnt
4247 
4248     unsigned Count = 0, RORefCnt = 0, WORefCnt = 0;
4249     for (auto &RI : FS->refs()) {
4250       auto RefValueId = getValueId(RI.getGUID());
4251       if (!RefValueId)
4252         continue;
4253       NameVals.push_back(*RefValueId);
4254       if (RI.isReadOnly())
4255         RORefCnt++;
4256       else if (RI.isWriteOnly())
4257         WORefCnt++;
4258       Count++;
4259     }
4260     NameVals[6] = Count;
4261     NameVals[7] = RORefCnt;
4262     NameVals[8] = WORefCnt;
4263 
4264     bool HasProfileData = false;
4265     for (auto &EI : FS->calls()) {
4266       HasProfileData |=
4267           EI.second.getHotness() != CalleeInfo::HotnessType::Unknown;
4268       if (HasProfileData)
4269         break;
4270     }
4271 
4272     for (auto &EI : FS->calls()) {
4273       // If this GUID doesn't have a value id, it doesn't have a function
4274       // summary and we don't need to record any calls to it.
4275       Optional<unsigned> CallValueId = GetValueId(EI.first);
4276       if (!CallValueId)
4277         continue;
4278       NameVals.push_back(*CallValueId);
4279       if (HasProfileData)
4280         NameVals.push_back(static_cast<uint8_t>(EI.second.Hotness));
4281     }
4282 
4283     unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
4284     unsigned Code =
4285         (HasProfileData ? bitc::FS_COMBINED_PROFILE : bitc::FS_COMBINED);
4286 
4287     // Emit the finished record.
4288     Stream.EmitRecord(Code, NameVals, FSAbbrev);
4289     NameVals.clear();
4290     MaybeEmitOriginalName(*S);
4291   });
4292 
4293   for (auto *AS : Aliases) {
4294     auto AliasValueId = SummaryToValueIdMap[AS];
4295     assert(AliasValueId);
4296     NameVals.push_back(AliasValueId);
4297     NameVals.push_back(Index.getModuleId(AS->modulePath()));
4298     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
4299     auto AliaseeValueId = SummaryToValueIdMap[&AS->getAliasee()];
4300     assert(AliaseeValueId);
4301     NameVals.push_back(AliaseeValueId);
4302 
4303     // Emit the finished record.
4304     Stream.EmitRecord(bitc::FS_COMBINED_ALIAS, NameVals, FSAliasAbbrev);
4305     NameVals.clear();
4306     MaybeEmitOriginalName(*AS);
4307 
4308     if (auto *FS = dyn_cast<FunctionSummary>(&AS->getAliasee()))
4309       getReferencedTypeIds(FS, ReferencedTypeIds);
4310   }
4311 
4312   if (!Index.cfiFunctionDefs().empty()) {
4313     for (auto &S : Index.cfiFunctionDefs()) {
4314       if (DefOrUseGUIDs.count(
4315               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4316         NameVals.push_back(StrtabBuilder.add(S));
4317         NameVals.push_back(S.size());
4318       }
4319     }
4320     if (!NameVals.empty()) {
4321       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DEFS, NameVals);
4322       NameVals.clear();
4323     }
4324   }
4325 
4326   if (!Index.cfiFunctionDecls().empty()) {
4327     for (auto &S : Index.cfiFunctionDecls()) {
4328       if (DefOrUseGUIDs.count(
4329               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4330         NameVals.push_back(StrtabBuilder.add(S));
4331         NameVals.push_back(S.size());
4332       }
4333     }
4334     if (!NameVals.empty()) {
4335       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DECLS, NameVals);
4336       NameVals.clear();
4337     }
4338   }
4339 
4340   // Walk the GUIDs that were referenced, and write the
4341   // corresponding type id records.
4342   for (auto &T : ReferencedTypeIds) {
4343     auto TidIter = Index.typeIds().equal_range(T);
4344     for (auto It = TidIter.first; It != TidIter.second; ++It) {
4345       writeTypeIdSummaryRecord(NameVals, StrtabBuilder, It->second.first,
4346                                It->second.second);
4347       Stream.EmitRecord(bitc::FS_TYPE_ID, NameVals);
4348       NameVals.clear();
4349     }
4350   }
4351 
4352   Stream.EmitRecord(bitc::FS_BLOCK_COUNT,
4353                     ArrayRef<uint64_t>{Index.getBlockCount()});
4354 
4355   Stream.ExitBlock();
4356 }
4357 
4358 /// Create the "IDENTIFICATION_BLOCK_ID" containing a single string with the
4359 /// current llvm version, and a record for the epoch number.
4360 static void writeIdentificationBlock(BitstreamWriter &Stream) {
4361   Stream.EnterSubblock(bitc::IDENTIFICATION_BLOCK_ID, 5);
4362 
4363   // Write the "user readable" string identifying the bitcode producer
4364   auto Abbv = std::make_shared<BitCodeAbbrev>();
4365   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_STRING));
4366   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4367   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
4368   auto StringAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4369   writeStringRecord(Stream, bitc::IDENTIFICATION_CODE_STRING,
4370                     "LLVM" LLVM_VERSION_STRING, StringAbbrev);
4371 
4372   // Write the epoch version
4373   Abbv = std::make_shared<BitCodeAbbrev>();
4374   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_EPOCH));
4375   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
4376   auto EpochAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4377   constexpr std::array<unsigned, 1> Vals = {{bitc::BITCODE_CURRENT_EPOCH}};
4378   Stream.EmitRecord(bitc::IDENTIFICATION_CODE_EPOCH, Vals, EpochAbbrev);
4379   Stream.ExitBlock();
4380 }
4381 
4382 void ModuleBitcodeWriter::writeModuleHash(size_t BlockStartPos) {
4383   // Emit the module's hash.
4384   // MODULE_CODE_HASH: [5*i32]
4385   if (GenerateHash) {
4386     uint32_t Vals[5];
4387     Hasher.update(ArrayRef<uint8_t>((const uint8_t *)&(Buffer)[BlockStartPos],
4388                                     Buffer.size() - BlockStartPos));
4389     StringRef Hash = Hasher.result();
4390     for (int Pos = 0; Pos < 20; Pos += 4) {
4391       Vals[Pos / 4] = support::endian::read32be(Hash.data() + Pos);
4392     }
4393 
4394     // Emit the finished record.
4395     Stream.EmitRecord(bitc::MODULE_CODE_HASH, Vals);
4396 
4397     if (ModHash)
4398       // Save the written hash value.
4399       llvm::copy(Vals, std::begin(*ModHash));
4400   }
4401 }
4402 
4403 void ModuleBitcodeWriter::write() {
4404   writeIdentificationBlock(Stream);
4405 
4406   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4407   size_t BlockStartPos = Buffer.size();
4408 
4409   writeModuleVersion();
4410 
4411   // Emit blockinfo, which defines the standard abbreviations etc.
4412   writeBlockInfo();
4413 
4414   // Emit information describing all of the types in the module.
4415   writeTypeTable();
4416 
4417   // Emit information about attribute groups.
4418   writeAttributeGroupTable();
4419 
4420   // Emit information about parameter attributes.
4421   writeAttributeTable();
4422 
4423   writeComdats();
4424 
4425   // Emit top-level description of module, including target triple, inline asm,
4426   // descriptors for global variables, and function prototype info.
4427   writeModuleInfo();
4428 
4429   // Emit constants.
4430   writeModuleConstants();
4431 
4432   // Emit metadata kind names.
4433   writeModuleMetadataKinds();
4434 
4435   // Emit metadata.
4436   writeModuleMetadata();
4437 
4438   // Emit module-level use-lists.
4439   if (VE.shouldPreserveUseListOrder())
4440     writeUseListBlock(nullptr);
4441 
4442   writeOperandBundleTags();
4443   writeSyncScopeNames();
4444 
4445   // Emit function bodies.
4446   DenseMap<const Function *, uint64_t> FunctionToBitcodeIndex;
4447   for (Module::const_iterator F = M.begin(), E = M.end(); F != E; ++F)
4448     if (!F->isDeclaration())
4449       writeFunction(*F, FunctionToBitcodeIndex);
4450 
4451   // Need to write after the above call to WriteFunction which populates
4452   // the summary information in the index.
4453   if (Index)
4454     writePerModuleGlobalValueSummary();
4455 
4456   writeGlobalValueSymbolTable(FunctionToBitcodeIndex);
4457 
4458   writeModuleHash(BlockStartPos);
4459 
4460   Stream.ExitBlock();
4461 }
4462 
4463 static void writeInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
4464                                uint32_t &Position) {
4465   support::endian::write32le(&Buffer[Position], Value);
4466   Position += 4;
4467 }
4468 
4469 /// If generating a bc file on darwin, we have to emit a
4470 /// header and trailer to make it compatible with the system archiver.  To do
4471 /// this we emit the following header, and then emit a trailer that pads the
4472 /// file out to be a multiple of 16 bytes.
4473 ///
4474 /// struct bc_header {
4475 ///   uint32_t Magic;         // 0x0B17C0DE
4476 ///   uint32_t Version;       // Version, currently always 0.
4477 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
4478 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
4479 ///   uint32_t CPUType;       // CPU specifier.
4480 ///   ... potentially more later ...
4481 /// };
4482 static void emitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
4483                                          const Triple &TT) {
4484   unsigned CPUType = ~0U;
4485 
4486   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
4487   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
4488   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
4489   // specific constants here because they are implicitly part of the Darwin ABI.
4490   enum {
4491     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
4492     DARWIN_CPU_TYPE_X86        = 7,
4493     DARWIN_CPU_TYPE_ARM        = 12,
4494     DARWIN_CPU_TYPE_POWERPC    = 18
4495   };
4496 
4497   Triple::ArchType Arch = TT.getArch();
4498   if (Arch == Triple::x86_64)
4499     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
4500   else if (Arch == Triple::x86)
4501     CPUType = DARWIN_CPU_TYPE_X86;
4502   else if (Arch == Triple::ppc)
4503     CPUType = DARWIN_CPU_TYPE_POWERPC;
4504   else if (Arch == Triple::ppc64)
4505     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
4506   else if (Arch == Triple::arm || Arch == Triple::thumb)
4507     CPUType = DARWIN_CPU_TYPE_ARM;
4508 
4509   // Traditional Bitcode starts after header.
4510   assert(Buffer.size() >= BWH_HeaderSize &&
4511          "Expected header size to be reserved");
4512   unsigned BCOffset = BWH_HeaderSize;
4513   unsigned BCSize = Buffer.size() - BWH_HeaderSize;
4514 
4515   // Write the magic and version.
4516   unsigned Position = 0;
4517   writeInt32ToBuffer(0x0B17C0DE, Buffer, Position);
4518   writeInt32ToBuffer(0, Buffer, Position); // Version.
4519   writeInt32ToBuffer(BCOffset, Buffer, Position);
4520   writeInt32ToBuffer(BCSize, Buffer, Position);
4521   writeInt32ToBuffer(CPUType, Buffer, Position);
4522 
4523   // If the file is not a multiple of 16 bytes, insert dummy padding.
4524   while (Buffer.size() & 15)
4525     Buffer.push_back(0);
4526 }
4527 
4528 /// Helper to write the header common to all bitcode files.
4529 static void writeBitcodeHeader(BitstreamWriter &Stream) {
4530   // Emit the file header.
4531   Stream.Emit((unsigned)'B', 8);
4532   Stream.Emit((unsigned)'C', 8);
4533   Stream.Emit(0x0, 4);
4534   Stream.Emit(0xC, 4);
4535   Stream.Emit(0xE, 4);
4536   Stream.Emit(0xD, 4);
4537 }
4538 
4539 BitcodeWriter::BitcodeWriter(SmallVectorImpl<char> &Buffer, raw_fd_stream *FS)
4540     : Buffer(Buffer), Stream(new BitstreamWriter(Buffer, FS, FlushThreshold)) {
4541   writeBitcodeHeader(*Stream);
4542 }
4543 
4544 BitcodeWriter::~BitcodeWriter() { assert(WroteStrtab); }
4545 
4546 void BitcodeWriter::writeBlob(unsigned Block, unsigned Record, StringRef Blob) {
4547   Stream->EnterSubblock(Block, 3);
4548 
4549   auto Abbv = std::make_shared<BitCodeAbbrev>();
4550   Abbv->Add(BitCodeAbbrevOp(Record));
4551   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
4552   auto AbbrevNo = Stream->EmitAbbrev(std::move(Abbv));
4553 
4554   Stream->EmitRecordWithBlob(AbbrevNo, ArrayRef<uint64_t>{Record}, Blob);
4555 
4556   Stream->ExitBlock();
4557 }
4558 
4559 void BitcodeWriter::writeSymtab() {
4560   assert(!WroteStrtab && !WroteSymtab);
4561 
4562   // If any module has module-level inline asm, we will require a registered asm
4563   // parser for the target so that we can create an accurate symbol table for
4564   // the module.
4565   for (Module *M : Mods) {
4566     if (M->getModuleInlineAsm().empty())
4567       continue;
4568 
4569     std::string Err;
4570     const Triple TT(M->getTargetTriple());
4571     const Target *T = TargetRegistry::lookupTarget(TT.str(), Err);
4572     if (!T || !T->hasMCAsmParser())
4573       return;
4574   }
4575 
4576   WroteSymtab = true;
4577   SmallVector<char, 0> Symtab;
4578   // The irsymtab::build function may be unable to create a symbol table if the
4579   // module is malformed (e.g. it contains an invalid alias). Writing a symbol
4580   // table is not required for correctness, but we still want to be able to
4581   // write malformed modules to bitcode files, so swallow the error.
4582   if (Error E = irsymtab::build(Mods, Symtab, StrtabBuilder, Alloc)) {
4583     consumeError(std::move(E));
4584     return;
4585   }
4586 
4587   writeBlob(bitc::SYMTAB_BLOCK_ID, bitc::SYMTAB_BLOB,
4588             {Symtab.data(), Symtab.size()});
4589 }
4590 
4591 void BitcodeWriter::writeStrtab() {
4592   assert(!WroteStrtab);
4593 
4594   std::vector<char> Strtab;
4595   StrtabBuilder.finalizeInOrder();
4596   Strtab.resize(StrtabBuilder.getSize());
4597   StrtabBuilder.write((uint8_t *)Strtab.data());
4598 
4599   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB,
4600             {Strtab.data(), Strtab.size()});
4601 
4602   WroteStrtab = true;
4603 }
4604 
4605 void BitcodeWriter::copyStrtab(StringRef Strtab) {
4606   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB, Strtab);
4607   WroteStrtab = true;
4608 }
4609 
4610 void BitcodeWriter::writeModule(const Module &M,
4611                                 bool ShouldPreserveUseListOrder,
4612                                 const ModuleSummaryIndex *Index,
4613                                 bool GenerateHash, ModuleHash *ModHash) {
4614   assert(!WroteStrtab);
4615 
4616   // The Mods vector is used by irsymtab::build, which requires non-const
4617   // Modules in case it needs to materialize metadata. But the bitcode writer
4618   // requires that the module is materialized, so we can cast to non-const here,
4619   // after checking that it is in fact materialized.
4620   assert(M.isMaterialized());
4621   Mods.push_back(const_cast<Module *>(&M));
4622 
4623   ModuleBitcodeWriter ModuleWriter(M, Buffer, StrtabBuilder, *Stream,
4624                                    ShouldPreserveUseListOrder, Index,
4625                                    GenerateHash, ModHash);
4626   ModuleWriter.write();
4627 }
4628 
4629 void BitcodeWriter::writeIndex(
4630     const ModuleSummaryIndex *Index,
4631     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4632   IndexBitcodeWriter IndexWriter(*Stream, StrtabBuilder, *Index,
4633                                  ModuleToSummariesForIndex);
4634   IndexWriter.write();
4635 }
4636 
4637 /// Write the specified module to the specified output stream.
4638 void llvm::WriteBitcodeToFile(const Module &M, raw_ostream &Out,
4639                               bool ShouldPreserveUseListOrder,
4640                               const ModuleSummaryIndex *Index,
4641                               bool GenerateHash, ModuleHash *ModHash) {
4642   SmallVector<char, 0> Buffer;
4643   Buffer.reserve(256*1024);
4644 
4645   // If this is darwin or another generic macho target, reserve space for the
4646   // header.
4647   Triple TT(M.getTargetTriple());
4648   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4649     Buffer.insert(Buffer.begin(), BWH_HeaderSize, 0);
4650 
4651   BitcodeWriter Writer(Buffer, dyn_cast<raw_fd_stream>(&Out));
4652   Writer.writeModule(M, ShouldPreserveUseListOrder, Index, GenerateHash,
4653                      ModHash);
4654   Writer.writeSymtab();
4655   Writer.writeStrtab();
4656 
4657   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4658     emitDarwinBCHeaderAndTrailer(Buffer, TT);
4659 
4660   // Write the generated bitstream to "Out".
4661   if (!Buffer.empty())
4662     Out.write((char *)&Buffer.front(), Buffer.size());
4663 }
4664 
4665 void IndexBitcodeWriter::write() {
4666   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4667 
4668   writeModuleVersion();
4669 
4670   // Write the module paths in the combined index.
4671   writeModStrings();
4672 
4673   // Write the summary combined index records.
4674   writeCombinedGlobalValueSummary();
4675 
4676   Stream.ExitBlock();
4677 }
4678 
4679 // Write the specified module summary index to the given raw output stream,
4680 // where it will be written in a new bitcode block. This is used when
4681 // writing the combined index file for ThinLTO. When writing a subset of the
4682 // index for a distributed backend, provide a \p ModuleToSummariesForIndex map.
4683 void llvm::WriteIndexToFile(
4684     const ModuleSummaryIndex &Index, raw_ostream &Out,
4685     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4686   SmallVector<char, 0> Buffer;
4687   Buffer.reserve(256 * 1024);
4688 
4689   BitcodeWriter Writer(Buffer);
4690   Writer.writeIndex(&Index, ModuleToSummariesForIndex);
4691   Writer.writeStrtab();
4692 
4693   Out.write((char *)&Buffer.front(), Buffer.size());
4694 }
4695 
4696 namespace {
4697 
4698 /// Class to manage the bitcode writing for a thin link bitcode file.
4699 class ThinLinkBitcodeWriter : public ModuleBitcodeWriterBase {
4700   /// ModHash is for use in ThinLTO incremental build, generated while writing
4701   /// the module bitcode file.
4702   const ModuleHash *ModHash;
4703 
4704 public:
4705   ThinLinkBitcodeWriter(const Module &M, StringTableBuilder &StrtabBuilder,
4706                         BitstreamWriter &Stream,
4707                         const ModuleSummaryIndex &Index,
4708                         const ModuleHash &ModHash)
4709       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
4710                                 /*ShouldPreserveUseListOrder=*/false, &Index),
4711         ModHash(&ModHash) {}
4712 
4713   void write();
4714 
4715 private:
4716   void writeSimplifiedModuleInfo();
4717 };
4718 
4719 } // end anonymous namespace
4720 
4721 // This function writes a simpilified module info for thin link bitcode file.
4722 // It only contains the source file name along with the name(the offset and
4723 // size in strtab) and linkage for global values. For the global value info
4724 // entry, in order to keep linkage at offset 5, there are three zeros used
4725 // as padding.
4726 void ThinLinkBitcodeWriter::writeSimplifiedModuleInfo() {
4727   SmallVector<unsigned, 64> Vals;
4728   // Emit the module's source file name.
4729   {
4730     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
4731     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
4732     if (Bits == SE_Char6)
4733       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
4734     else if (Bits == SE_Fixed7)
4735       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
4736 
4737     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
4738     auto Abbv = std::make_shared<BitCodeAbbrev>();
4739     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
4740     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4741     Abbv->Add(AbbrevOpToUse);
4742     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4743 
4744     for (const auto P : M.getSourceFileName())
4745       Vals.push_back((unsigned char)P);
4746 
4747     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
4748     Vals.clear();
4749   }
4750 
4751   // Emit the global variable information.
4752   for (const GlobalVariable &GV : M.globals()) {
4753     // GLOBALVAR: [strtab offset, strtab size, 0, 0, 0, linkage]
4754     Vals.push_back(StrtabBuilder.add(GV.getName()));
4755     Vals.push_back(GV.getName().size());
4756     Vals.push_back(0);
4757     Vals.push_back(0);
4758     Vals.push_back(0);
4759     Vals.push_back(getEncodedLinkage(GV));
4760 
4761     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals);
4762     Vals.clear();
4763   }
4764 
4765   // Emit the function proto information.
4766   for (const Function &F : M) {
4767     // FUNCTION:  [strtab offset, strtab size, 0, 0, 0, linkage]
4768     Vals.push_back(StrtabBuilder.add(F.getName()));
4769     Vals.push_back(F.getName().size());
4770     Vals.push_back(0);
4771     Vals.push_back(0);
4772     Vals.push_back(0);
4773     Vals.push_back(getEncodedLinkage(F));
4774 
4775     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals);
4776     Vals.clear();
4777   }
4778 
4779   // Emit the alias information.
4780   for (const GlobalAlias &A : M.aliases()) {
4781     // ALIAS: [strtab offset, strtab size, 0, 0, 0, linkage]
4782     Vals.push_back(StrtabBuilder.add(A.getName()));
4783     Vals.push_back(A.getName().size());
4784     Vals.push_back(0);
4785     Vals.push_back(0);
4786     Vals.push_back(0);
4787     Vals.push_back(getEncodedLinkage(A));
4788 
4789     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals);
4790     Vals.clear();
4791   }
4792 
4793   // Emit the ifunc information.
4794   for (const GlobalIFunc &I : M.ifuncs()) {
4795     // IFUNC: [strtab offset, strtab size, 0, 0, 0, linkage]
4796     Vals.push_back(StrtabBuilder.add(I.getName()));
4797     Vals.push_back(I.getName().size());
4798     Vals.push_back(0);
4799     Vals.push_back(0);
4800     Vals.push_back(0);
4801     Vals.push_back(getEncodedLinkage(I));
4802 
4803     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
4804     Vals.clear();
4805   }
4806 }
4807 
4808 void ThinLinkBitcodeWriter::write() {
4809   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4810 
4811   writeModuleVersion();
4812 
4813   writeSimplifiedModuleInfo();
4814 
4815   writePerModuleGlobalValueSummary();
4816 
4817   // Write module hash.
4818   Stream.EmitRecord(bitc::MODULE_CODE_HASH, ArrayRef<uint32_t>(*ModHash));
4819 
4820   Stream.ExitBlock();
4821 }
4822 
4823 void BitcodeWriter::writeThinLinkBitcode(const Module &M,
4824                                          const ModuleSummaryIndex &Index,
4825                                          const ModuleHash &ModHash) {
4826   assert(!WroteStrtab);
4827 
4828   // The Mods vector is used by irsymtab::build, which requires non-const
4829   // Modules in case it needs to materialize metadata. But the bitcode writer
4830   // requires that the module is materialized, so we can cast to non-const here,
4831   // after checking that it is in fact materialized.
4832   assert(M.isMaterialized());
4833   Mods.push_back(const_cast<Module *>(&M));
4834 
4835   ThinLinkBitcodeWriter ThinLinkWriter(M, StrtabBuilder, *Stream, Index,
4836                                        ModHash);
4837   ThinLinkWriter.write();
4838 }
4839 
4840 // Write the specified thin link bitcode file to the given raw output stream,
4841 // where it will be written in a new bitcode block. This is used when
4842 // writing the per-module index file for ThinLTO.
4843 void llvm::WriteThinLinkBitcodeToFile(const Module &M, raw_ostream &Out,
4844                                       const ModuleSummaryIndex &Index,
4845                                       const ModuleHash &ModHash) {
4846   SmallVector<char, 0> Buffer;
4847   Buffer.reserve(256 * 1024);
4848 
4849   BitcodeWriter Writer(Buffer);
4850   Writer.writeThinLinkBitcode(M, Index, ModHash);
4851   Writer.writeSymtab();
4852   Writer.writeStrtab();
4853 
4854   Out.write((char *)&Buffer.front(), Buffer.size());
4855 }
4856 
4857 static const char *getSectionNameForBitcode(const Triple &T) {
4858   switch (T.getObjectFormat()) {
4859   case Triple::MachO:
4860     return "__LLVM,__bitcode";
4861   case Triple::COFF:
4862   case Triple::ELF:
4863   case Triple::Wasm:
4864   case Triple::UnknownObjectFormat:
4865     return ".llvmbc";
4866   case Triple::GOFF:
4867     llvm_unreachable("GOFF is not yet implemented");
4868     break;
4869   case Triple::XCOFF:
4870     llvm_unreachable("XCOFF is not yet implemented");
4871     break;
4872   }
4873   llvm_unreachable("Unimplemented ObjectFormatType");
4874 }
4875 
4876 static const char *getSectionNameForCommandline(const Triple &T) {
4877   switch (T.getObjectFormat()) {
4878   case Triple::MachO:
4879     return "__LLVM,__cmdline";
4880   case Triple::COFF:
4881   case Triple::ELF:
4882   case Triple::Wasm:
4883   case Triple::UnknownObjectFormat:
4884     return ".llvmcmd";
4885   case Triple::GOFF:
4886     llvm_unreachable("GOFF is not yet implemented");
4887     break;
4888   case Triple::XCOFF:
4889     llvm_unreachable("XCOFF is not yet implemented");
4890     break;
4891   }
4892   llvm_unreachable("Unimplemented ObjectFormatType");
4893 }
4894 
4895 void llvm::EmbedBitcodeInModule(llvm::Module &M, llvm::MemoryBufferRef Buf,
4896                                 bool EmbedBitcode, bool EmbedCmdline,
4897                                 const std::vector<uint8_t> &CmdArgs) {
4898   // Save llvm.compiler.used and remove it.
4899   SmallVector<Constant *, 2> UsedArray;
4900   SmallVector<GlobalValue *, 4> UsedGlobals;
4901   Type *UsedElementType = Type::getInt8Ty(M.getContext())->getPointerTo(0);
4902   GlobalVariable *Used = collectUsedGlobalVariables(M, UsedGlobals, true);
4903   for (auto *GV : UsedGlobals) {
4904     if (GV->getName() != "llvm.embedded.module" &&
4905         GV->getName() != "llvm.cmdline")
4906       UsedArray.push_back(
4907           ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
4908   }
4909   if (Used)
4910     Used->eraseFromParent();
4911 
4912   // Embed the bitcode for the llvm module.
4913   std::string Data;
4914   ArrayRef<uint8_t> ModuleData;
4915   Triple T(M.getTargetTriple());
4916 
4917   if (EmbedBitcode) {
4918     if (Buf.getBufferSize() == 0 ||
4919         !isBitcode((const unsigned char *)Buf.getBufferStart(),
4920                    (const unsigned char *)Buf.getBufferEnd())) {
4921       // If the input is LLVM Assembly, bitcode is produced by serializing
4922       // the module. Use-lists order need to be preserved in this case.
4923       llvm::raw_string_ostream OS(Data);
4924       llvm::WriteBitcodeToFile(M, OS, /* ShouldPreserveUseListOrder */ true);
4925       ModuleData =
4926           ArrayRef<uint8_t>((const uint8_t *)OS.str().data(), OS.str().size());
4927     } else
4928       // If the input is LLVM bitcode, write the input byte stream directly.
4929       ModuleData = ArrayRef<uint8_t>((const uint8_t *)Buf.getBufferStart(),
4930                                      Buf.getBufferSize());
4931   }
4932   llvm::Constant *ModuleConstant =
4933       llvm::ConstantDataArray::get(M.getContext(), ModuleData);
4934   llvm::GlobalVariable *GV = new llvm::GlobalVariable(
4935       M, ModuleConstant->getType(), true, llvm::GlobalValue::PrivateLinkage,
4936       ModuleConstant);
4937   GV->setSection(getSectionNameForBitcode(T));
4938   // Set alignment to 1 to prevent padding between two contributions from input
4939   // sections after linking.
4940   GV->setAlignment(Align(1));
4941   UsedArray.push_back(
4942       ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
4943   if (llvm::GlobalVariable *Old =
4944           M.getGlobalVariable("llvm.embedded.module", true)) {
4945     assert(Old->hasOneUse() &&
4946            "llvm.embedded.module can only be used once in llvm.compiler.used");
4947     GV->takeName(Old);
4948     Old->eraseFromParent();
4949   } else {
4950     GV->setName("llvm.embedded.module");
4951   }
4952 
4953   // Skip if only bitcode needs to be embedded.
4954   if (EmbedCmdline) {
4955     // Embed command-line options.
4956     ArrayRef<uint8_t> CmdData(const_cast<uint8_t *>(CmdArgs.data()),
4957                               CmdArgs.size());
4958     llvm::Constant *CmdConstant =
4959         llvm::ConstantDataArray::get(M.getContext(), CmdData);
4960     GV = new llvm::GlobalVariable(M, CmdConstant->getType(), true,
4961                                   llvm::GlobalValue::PrivateLinkage,
4962                                   CmdConstant);
4963     GV->setSection(getSectionNameForCommandline(T));
4964     GV->setAlignment(Align(1));
4965     UsedArray.push_back(
4966         ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
4967     if (llvm::GlobalVariable *Old = M.getGlobalVariable("llvm.cmdline", true)) {
4968       assert(Old->hasOneUse() &&
4969              "llvm.cmdline can only be used once in llvm.compiler.used");
4970       GV->takeName(Old);
4971       Old->eraseFromParent();
4972     } else {
4973       GV->setName("llvm.cmdline");
4974     }
4975   }
4976 
4977   if (UsedArray.empty())
4978     return;
4979 
4980   // Recreate llvm.compiler.used.
4981   ArrayType *ATy = ArrayType::get(UsedElementType, UsedArray.size());
4982   auto *NewUsed = new GlobalVariable(
4983       M, ATy, false, llvm::GlobalValue::AppendingLinkage,
4984       llvm::ConstantArray::get(ATy, UsedArray), "llvm.compiler.used");
4985   NewUsed->setSection("llvm.metadata");
4986 }
4987