xref: /llvm-project/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp (revision 11201315d5881a135faa5aa87f415ce03f99eb96)
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 writeBitcodeHeader();
146   void writeModuleVersion();
147 };
148 
149 void BitcodeWriterBase::writeModuleVersion() {
150   // VERSION: [version#]
151   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, ArrayRef<uint64_t>{2});
152 }
153 
154 /// Base class to manage the module bitcode writing, currently subclassed for
155 /// ModuleBitcodeWriter and ThinLinkBitcodeWriter.
156 class ModuleBitcodeWriterBase : public BitcodeWriterBase {
157 protected:
158   /// The Module to write to bitcode.
159   const Module &M;
160 
161   /// Enumerates ids for all values in the module.
162   ValueEnumerator VE;
163 
164   /// Optional per-module index to write for ThinLTO.
165   const ModuleSummaryIndex *Index;
166 
167   /// Map that holds the correspondence between GUIDs in the summary index,
168   /// that came from indirect call profiles, and a value id generated by this
169   /// class to use in the VST and summary block records.
170   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
171 
172   /// Tracks the last value id recorded in the GUIDToValueMap.
173   unsigned GlobalValueId;
174 
175   /// Saves the offset of the VSTOffset record that must eventually be
176   /// backpatched with the offset of the actual VST.
177   uint64_t VSTOffsetPlaceholder = 0;
178 
179 public:
180   /// Constructs a ModuleBitcodeWriterBase object for the given Module,
181   /// writing to the provided \p Buffer.
182   ModuleBitcodeWriterBase(const Module &M, StringTableBuilder &StrtabBuilder,
183                           BitstreamWriter &Stream,
184                           bool ShouldPreserveUseListOrder,
185                           const ModuleSummaryIndex *Index)
186       : BitcodeWriterBase(Stream, StrtabBuilder), M(M),
187         VE(M, ShouldPreserveUseListOrder), Index(Index) {
188     // Assign ValueIds to any callee values in the index that came from
189     // indirect call profiles and were recorded as a GUID not a Value*
190     // (which would have been assigned an ID by the ValueEnumerator).
191     // The starting ValueId is just after the number of values in the
192     // ValueEnumerator, so that they can be emitted in the VST.
193     GlobalValueId = VE.getValues().size();
194     if (!Index)
195       return;
196     for (const auto &GUIDSummaryLists : *Index)
197       // Examine all summaries for this GUID.
198       for (auto &Summary : GUIDSummaryLists.second.SummaryList)
199         if (auto FS = dyn_cast<FunctionSummary>(Summary.get()))
200           // For each call in the function summary, see if the call
201           // is to a GUID (which means it is for an indirect call,
202           // otherwise we would have a Value for it). If so, synthesize
203           // a value id.
204           for (auto &CallEdge : FS->calls())
205             if (!CallEdge.first.haveGVs() || !CallEdge.first.getValue())
206               assignValueId(CallEdge.first.getGUID());
207   }
208 
209 protected:
210   void writePerModuleGlobalValueSummary();
211 
212 private:
213   void writePerModuleFunctionSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
214                                            GlobalValueSummary *Summary,
215                                            unsigned ValueID,
216                                            unsigned FSCallsAbbrev,
217                                            unsigned FSCallsProfileAbbrev,
218                                            const Function &F);
219   void writeModuleLevelReferences(const GlobalVariable &V,
220                                   SmallVector<uint64_t, 64> &NameVals,
221                                   unsigned FSModRefsAbbrev,
222                                   unsigned FSModVTableRefsAbbrev);
223 
224   void assignValueId(GlobalValue::GUID ValGUID) {
225     GUIDToValueIdMap[ValGUID] = ++GlobalValueId;
226   }
227 
228   unsigned getValueId(GlobalValue::GUID ValGUID) {
229     const auto &VMI = GUIDToValueIdMap.find(ValGUID);
230     // Expect that any GUID value had a value Id assigned by an
231     // earlier call to assignValueId.
232     assert(VMI != GUIDToValueIdMap.end() &&
233            "GUID does not have assigned value Id");
234     return VMI->second;
235   }
236 
237   // Helper to get the valueId for the type of value recorded in VI.
238   unsigned getValueId(ValueInfo VI) {
239     if (!VI.haveGVs() || !VI.getValue())
240       return getValueId(VI.getGUID());
241     return VE.getValueID(VI.getValue());
242   }
243 
244   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
245 };
246 
247 /// Class to manage the bitcode writing for a module.
248 class ModuleBitcodeWriter : public ModuleBitcodeWriterBase {
249   /// Pointer to the buffer allocated by caller for bitcode writing.
250   const SmallVectorImpl<char> &Buffer;
251 
252   /// True if a module hash record should be written.
253   bool GenerateHash;
254 
255   /// If non-null, when GenerateHash is true, the resulting hash is written
256   /// into ModHash.
257   ModuleHash *ModHash;
258 
259   SHA1 Hasher;
260 
261   /// The start bit of the identification block.
262   uint64_t BitcodeStartBit;
263 
264 public:
265   /// Constructs a ModuleBitcodeWriter object for the given Module,
266   /// writing to the provided \p Buffer.
267   ModuleBitcodeWriter(const Module &M, SmallVectorImpl<char> &Buffer,
268                       StringTableBuilder &StrtabBuilder,
269                       BitstreamWriter &Stream, bool ShouldPreserveUseListOrder,
270                       const ModuleSummaryIndex *Index, bool GenerateHash,
271                       ModuleHash *ModHash = nullptr)
272       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
273                                 ShouldPreserveUseListOrder, Index),
274         Buffer(Buffer), GenerateHash(GenerateHash), ModHash(ModHash),
275         BitcodeStartBit(Stream.GetCurrentBitNo()) {}
276 
277   /// Emit the current module to the bitstream.
278   void write();
279 
280 private:
281   uint64_t bitcodeStartBit() { return BitcodeStartBit; }
282 
283   size_t addToStrtab(StringRef Str);
284 
285   void writeAttributeGroupTable();
286   void writeAttributeTable();
287   void writeTypeTable();
288   void writeComdats();
289   void writeValueSymbolTableForwardDecl();
290   void writeModuleInfo();
291   void writeValueAsMetadata(const ValueAsMetadata *MD,
292                             SmallVectorImpl<uint64_t> &Record);
293   void writeMDTuple(const MDTuple *N, SmallVectorImpl<uint64_t> &Record,
294                     unsigned Abbrev);
295   unsigned createDILocationAbbrev();
296   void writeDILocation(const DILocation *N, SmallVectorImpl<uint64_t> &Record,
297                        unsigned &Abbrev);
298   unsigned createGenericDINodeAbbrev();
299   void writeGenericDINode(const GenericDINode *N,
300                           SmallVectorImpl<uint64_t> &Record, unsigned &Abbrev);
301   void writeDISubrange(const DISubrange *N, SmallVectorImpl<uint64_t> &Record,
302                        unsigned Abbrev);
303   void writeDIEnumerator(const DIEnumerator *N,
304                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
305   void writeDIBasicType(const DIBasicType *N, SmallVectorImpl<uint64_t> &Record,
306                         unsigned Abbrev);
307   void writeDIStringType(const DIStringType *N,
308                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
309   void writeDIDerivedType(const DIDerivedType *N,
310                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
311   void writeDICompositeType(const DICompositeType *N,
312                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
313   void writeDISubroutineType(const DISubroutineType *N,
314                              SmallVectorImpl<uint64_t> &Record,
315                              unsigned Abbrev);
316   void writeDIFile(const DIFile *N, SmallVectorImpl<uint64_t> &Record,
317                    unsigned Abbrev);
318   void writeDICompileUnit(const DICompileUnit *N,
319                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
320   void writeDISubprogram(const DISubprogram *N,
321                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
322   void writeDILexicalBlock(const DILexicalBlock *N,
323                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
324   void writeDILexicalBlockFile(const DILexicalBlockFile *N,
325                                SmallVectorImpl<uint64_t> &Record,
326                                unsigned Abbrev);
327   void writeDICommonBlock(const DICommonBlock *N,
328                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
329   void writeDINamespace(const DINamespace *N, SmallVectorImpl<uint64_t> &Record,
330                         unsigned Abbrev);
331   void writeDIMacro(const DIMacro *N, SmallVectorImpl<uint64_t> &Record,
332                     unsigned Abbrev);
333   void writeDIMacroFile(const DIMacroFile *N, SmallVectorImpl<uint64_t> &Record,
334                         unsigned Abbrev);
335   void writeDIModule(const DIModule *N, SmallVectorImpl<uint64_t> &Record,
336                      unsigned Abbrev);
337   void writeDITemplateTypeParameter(const DITemplateTypeParameter *N,
338                                     SmallVectorImpl<uint64_t> &Record,
339                                     unsigned Abbrev);
340   void writeDITemplateValueParameter(const DITemplateValueParameter *N,
341                                      SmallVectorImpl<uint64_t> &Record,
342                                      unsigned Abbrev);
343   void writeDIGlobalVariable(const DIGlobalVariable *N,
344                              SmallVectorImpl<uint64_t> &Record,
345                              unsigned Abbrev);
346   void writeDILocalVariable(const DILocalVariable *N,
347                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
348   void writeDILabel(const DILabel *N,
349                     SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
350   void writeDIExpression(const DIExpression *N,
351                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
352   void writeDIGlobalVariableExpression(const DIGlobalVariableExpression *N,
353                                        SmallVectorImpl<uint64_t> &Record,
354                                        unsigned Abbrev);
355   void writeDIObjCProperty(const DIObjCProperty *N,
356                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
357   void writeDIImportedEntity(const DIImportedEntity *N,
358                              SmallVectorImpl<uint64_t> &Record,
359                              unsigned Abbrev);
360   unsigned createNamedMetadataAbbrev();
361   void writeNamedMetadata(SmallVectorImpl<uint64_t> &Record);
362   unsigned createMetadataStringsAbbrev();
363   void writeMetadataStrings(ArrayRef<const Metadata *> Strings,
364                             SmallVectorImpl<uint64_t> &Record);
365   void writeMetadataRecords(ArrayRef<const Metadata *> MDs,
366                             SmallVectorImpl<uint64_t> &Record,
367                             std::vector<unsigned> *MDAbbrevs = nullptr,
368                             std::vector<uint64_t> *IndexPos = nullptr);
369   void writeModuleMetadata();
370   void writeFunctionMetadata(const Function &F);
371   void writeFunctionMetadataAttachment(const Function &F);
372   void writeGlobalVariableMetadataAttachment(const GlobalVariable &GV);
373   void pushGlobalMetadataAttachment(SmallVectorImpl<uint64_t> &Record,
374                                     const GlobalObject &GO);
375   void writeModuleMetadataKinds();
376   void writeOperandBundleTags();
377   void writeSyncScopeNames();
378   void writeConstants(unsigned FirstVal, unsigned LastVal, bool isGlobal);
379   void writeModuleConstants();
380   bool pushValueAndType(const Value *V, unsigned InstID,
381                         SmallVectorImpl<unsigned> &Vals);
382   void writeOperandBundles(const CallBase &CB, unsigned InstID);
383   void pushValue(const Value *V, unsigned InstID,
384                  SmallVectorImpl<unsigned> &Vals);
385   void pushValueSigned(const Value *V, unsigned InstID,
386                        SmallVectorImpl<uint64_t> &Vals);
387   void writeInstruction(const Instruction &I, unsigned InstID,
388                         SmallVectorImpl<unsigned> &Vals);
389   void writeFunctionLevelValueSymbolTable(const ValueSymbolTable &VST);
390   void writeGlobalValueSymbolTable(
391       DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
392   void writeUseList(UseListOrder &&Order);
393   void writeUseListBlock(const Function *F);
394   void
395   writeFunction(const Function &F,
396                 DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
397   void writeBlockInfo();
398   void writeModuleHash(size_t BlockStartPos);
399 
400   unsigned getEncodedSyncScopeID(SyncScope::ID SSID) {
401     return unsigned(SSID);
402   }
403 
404   unsigned getEncodedAlign(MaybeAlign Alignment) { return encode(Alignment); }
405 };
406 
407 /// Class to manage the bitcode writing for a combined index.
408 class IndexBitcodeWriter : public BitcodeWriterBase {
409   /// The combined index to write to bitcode.
410   const ModuleSummaryIndex &Index;
411 
412   /// When writing a subset of the index for distributed backends, client
413   /// provides a map of modules to the corresponding GUIDs/summaries to write.
414   const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex;
415 
416   /// Map that holds the correspondence between the GUID used in the combined
417   /// index and a value id generated by this class to use in references.
418   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
419 
420   /// Tracks the last value id recorded in the GUIDToValueMap.
421   unsigned GlobalValueId = 0;
422 
423 public:
424   /// Constructs a IndexBitcodeWriter object for the given combined index,
425   /// writing to the provided \p Buffer. When writing a subset of the index
426   /// for a distributed backend, provide a \p ModuleToSummariesForIndex map.
427   IndexBitcodeWriter(BitstreamWriter &Stream, StringTableBuilder &StrtabBuilder,
428                      const ModuleSummaryIndex &Index,
429                      const std::map<std::string, GVSummaryMapTy>
430                          *ModuleToSummariesForIndex = nullptr)
431       : BitcodeWriterBase(Stream, StrtabBuilder), Index(Index),
432         ModuleToSummariesForIndex(ModuleToSummariesForIndex) {
433     // Assign unique value ids to all summaries to be written, for use
434     // in writing out the call graph edges. Save the mapping from GUID
435     // to the new global value id to use when writing those edges, which
436     // are currently saved in the index in terms of GUID.
437     forEachSummary([&](GVInfo I, bool) {
438       GUIDToValueIdMap[I.first] = ++GlobalValueId;
439     });
440   }
441 
442   /// The below iterator returns the GUID and associated summary.
443   using GVInfo = std::pair<GlobalValue::GUID, GlobalValueSummary *>;
444 
445   /// Calls the callback for each value GUID and summary to be written to
446   /// bitcode. This hides the details of whether they are being pulled from the
447   /// entire index or just those in a provided ModuleToSummariesForIndex map.
448   template<typename Functor>
449   void forEachSummary(Functor Callback) {
450     if (ModuleToSummariesForIndex) {
451       for (auto &M : *ModuleToSummariesForIndex)
452         for (auto &Summary : M.second) {
453           Callback(Summary, false);
454           // Ensure aliasee is handled, e.g. for assigning a valueId,
455           // even if we are not importing the aliasee directly (the
456           // imported alias will contain a copy of aliasee).
457           if (auto *AS = dyn_cast<AliasSummary>(Summary.getSecond()))
458             Callback({AS->getAliaseeGUID(), &AS->getAliasee()}, true);
459         }
460     } else {
461       for (auto &Summaries : Index)
462         for (auto &Summary : Summaries.second.SummaryList)
463           Callback({Summaries.first, Summary.get()}, false);
464     }
465   }
466 
467   /// Calls the callback for each entry in the modulePaths StringMap that
468   /// should be written to the module path string table. This hides the details
469   /// of whether they are being pulled from the entire index or just those in a
470   /// provided ModuleToSummariesForIndex map.
471   template <typename Functor> void forEachModule(Functor Callback) {
472     if (ModuleToSummariesForIndex) {
473       for (const auto &M : *ModuleToSummariesForIndex) {
474         const auto &MPI = Index.modulePaths().find(M.first);
475         if (MPI == Index.modulePaths().end()) {
476           // This should only happen if the bitcode file was empty, in which
477           // case we shouldn't be importing (the ModuleToSummariesForIndex
478           // would only include the module we are writing and index for).
479           assert(ModuleToSummariesForIndex->size() == 1);
480           continue;
481         }
482         Callback(*MPI);
483       }
484     } else {
485       for (const auto &MPSE : Index.modulePaths())
486         Callback(MPSE);
487     }
488   }
489 
490   /// Main entry point for writing a combined index to bitcode.
491   void write();
492 
493 private:
494   void writeModStrings();
495   void writeCombinedGlobalValueSummary();
496 
497   Optional<unsigned> getValueId(GlobalValue::GUID ValGUID) {
498     auto VMI = GUIDToValueIdMap.find(ValGUID);
499     if (VMI == GUIDToValueIdMap.end())
500       return None;
501     return VMI->second;
502   }
503 
504   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
505 };
506 
507 } // end anonymous namespace
508 
509 static unsigned getEncodedCastOpcode(unsigned Opcode) {
510   switch (Opcode) {
511   default: llvm_unreachable("Unknown cast instruction!");
512   case Instruction::Trunc   : return bitc::CAST_TRUNC;
513   case Instruction::ZExt    : return bitc::CAST_ZEXT;
514   case Instruction::SExt    : return bitc::CAST_SEXT;
515   case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
516   case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
517   case Instruction::UIToFP  : return bitc::CAST_UITOFP;
518   case Instruction::SIToFP  : return bitc::CAST_SITOFP;
519   case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
520   case Instruction::FPExt   : return bitc::CAST_FPEXT;
521   case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
522   case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
523   case Instruction::BitCast : return bitc::CAST_BITCAST;
524   case Instruction::AddrSpaceCast: return bitc::CAST_ADDRSPACECAST;
525   }
526 }
527 
528 static unsigned getEncodedUnaryOpcode(unsigned Opcode) {
529   switch (Opcode) {
530   default: llvm_unreachable("Unknown binary instruction!");
531   case Instruction::FNeg: return bitc::UNOP_FNEG;
532   }
533 }
534 
535 static unsigned getEncodedBinaryOpcode(unsigned Opcode) {
536   switch (Opcode) {
537   default: llvm_unreachable("Unknown binary instruction!");
538   case Instruction::Add:
539   case Instruction::FAdd: return bitc::BINOP_ADD;
540   case Instruction::Sub:
541   case Instruction::FSub: return bitc::BINOP_SUB;
542   case Instruction::Mul:
543   case Instruction::FMul: return bitc::BINOP_MUL;
544   case Instruction::UDiv: return bitc::BINOP_UDIV;
545   case Instruction::FDiv:
546   case Instruction::SDiv: return bitc::BINOP_SDIV;
547   case Instruction::URem: return bitc::BINOP_UREM;
548   case Instruction::FRem:
549   case Instruction::SRem: return bitc::BINOP_SREM;
550   case Instruction::Shl:  return bitc::BINOP_SHL;
551   case Instruction::LShr: return bitc::BINOP_LSHR;
552   case Instruction::AShr: return bitc::BINOP_ASHR;
553   case Instruction::And:  return bitc::BINOP_AND;
554   case Instruction::Or:   return bitc::BINOP_OR;
555   case Instruction::Xor:  return bitc::BINOP_XOR;
556   }
557 }
558 
559 static unsigned getEncodedRMWOperation(AtomicRMWInst::BinOp Op) {
560   switch (Op) {
561   default: llvm_unreachable("Unknown RMW operation!");
562   case AtomicRMWInst::Xchg: return bitc::RMW_XCHG;
563   case AtomicRMWInst::Add: return bitc::RMW_ADD;
564   case AtomicRMWInst::Sub: return bitc::RMW_SUB;
565   case AtomicRMWInst::And: return bitc::RMW_AND;
566   case AtomicRMWInst::Nand: return bitc::RMW_NAND;
567   case AtomicRMWInst::Or: return bitc::RMW_OR;
568   case AtomicRMWInst::Xor: return bitc::RMW_XOR;
569   case AtomicRMWInst::Max: return bitc::RMW_MAX;
570   case AtomicRMWInst::Min: return bitc::RMW_MIN;
571   case AtomicRMWInst::UMax: return bitc::RMW_UMAX;
572   case AtomicRMWInst::UMin: return bitc::RMW_UMIN;
573   case AtomicRMWInst::FAdd: return bitc::RMW_FADD;
574   case AtomicRMWInst::FSub: return bitc::RMW_FSUB;
575   }
576 }
577 
578 static unsigned getEncodedOrdering(AtomicOrdering Ordering) {
579   switch (Ordering) {
580   case AtomicOrdering::NotAtomic: return bitc::ORDERING_NOTATOMIC;
581   case AtomicOrdering::Unordered: return bitc::ORDERING_UNORDERED;
582   case AtomicOrdering::Monotonic: return bitc::ORDERING_MONOTONIC;
583   case AtomicOrdering::Acquire: return bitc::ORDERING_ACQUIRE;
584   case AtomicOrdering::Release: return bitc::ORDERING_RELEASE;
585   case AtomicOrdering::AcquireRelease: return bitc::ORDERING_ACQREL;
586   case AtomicOrdering::SequentiallyConsistent: return bitc::ORDERING_SEQCST;
587   }
588   llvm_unreachable("Invalid ordering");
589 }
590 
591 static void writeStringRecord(BitstreamWriter &Stream, unsigned Code,
592                               StringRef Str, unsigned AbbrevToUse) {
593   SmallVector<unsigned, 64> Vals;
594 
595   // Code: [strchar x N]
596   for (unsigned i = 0, e = Str.size(); i != e; ++i) {
597     if (AbbrevToUse && !BitCodeAbbrevOp::isChar6(Str[i]))
598       AbbrevToUse = 0;
599     Vals.push_back(Str[i]);
600   }
601 
602   // Emit the finished record.
603   Stream.EmitRecord(Code, Vals, AbbrevToUse);
604 }
605 
606 static uint64_t getAttrKindEncoding(Attribute::AttrKind Kind) {
607   switch (Kind) {
608   case Attribute::Alignment:
609     return bitc::ATTR_KIND_ALIGNMENT;
610   case Attribute::AllocSize:
611     return bitc::ATTR_KIND_ALLOC_SIZE;
612   case Attribute::AlwaysInline:
613     return bitc::ATTR_KIND_ALWAYS_INLINE;
614   case Attribute::ArgMemOnly:
615     return bitc::ATTR_KIND_ARGMEMONLY;
616   case Attribute::Builtin:
617     return bitc::ATTR_KIND_BUILTIN;
618   case Attribute::ByVal:
619     return bitc::ATTR_KIND_BY_VAL;
620   case Attribute::Convergent:
621     return bitc::ATTR_KIND_CONVERGENT;
622   case Attribute::InAlloca:
623     return bitc::ATTR_KIND_IN_ALLOCA;
624   case Attribute::Cold:
625     return bitc::ATTR_KIND_COLD;
626   case Attribute::InaccessibleMemOnly:
627     return bitc::ATTR_KIND_INACCESSIBLEMEM_ONLY;
628   case Attribute::InaccessibleMemOrArgMemOnly:
629     return bitc::ATTR_KIND_INACCESSIBLEMEM_OR_ARGMEMONLY;
630   case Attribute::InlineHint:
631     return bitc::ATTR_KIND_INLINE_HINT;
632   case Attribute::InReg:
633     return bitc::ATTR_KIND_IN_REG;
634   case Attribute::JumpTable:
635     return bitc::ATTR_KIND_JUMP_TABLE;
636   case Attribute::MinSize:
637     return bitc::ATTR_KIND_MIN_SIZE;
638   case Attribute::Naked:
639     return bitc::ATTR_KIND_NAKED;
640   case Attribute::Nest:
641     return bitc::ATTR_KIND_NEST;
642   case Attribute::NoAlias:
643     return bitc::ATTR_KIND_NO_ALIAS;
644   case Attribute::NoBuiltin:
645     return bitc::ATTR_KIND_NO_BUILTIN;
646   case Attribute::NoCapture:
647     return bitc::ATTR_KIND_NO_CAPTURE;
648   case Attribute::NoDuplicate:
649     return bitc::ATTR_KIND_NO_DUPLICATE;
650   case Attribute::NoFree:
651     return bitc::ATTR_KIND_NOFREE;
652   case Attribute::NoImplicitFloat:
653     return bitc::ATTR_KIND_NO_IMPLICIT_FLOAT;
654   case Attribute::NoInline:
655     return bitc::ATTR_KIND_NO_INLINE;
656   case Attribute::NoRecurse:
657     return bitc::ATTR_KIND_NO_RECURSE;
658   case Attribute::NoMerge:
659     return bitc::ATTR_KIND_NO_MERGE;
660   case Attribute::NonLazyBind:
661     return bitc::ATTR_KIND_NON_LAZY_BIND;
662   case Attribute::NonNull:
663     return bitc::ATTR_KIND_NON_NULL;
664   case Attribute::Dereferenceable:
665     return bitc::ATTR_KIND_DEREFERENCEABLE;
666   case Attribute::DereferenceableOrNull:
667     return bitc::ATTR_KIND_DEREFERENCEABLE_OR_NULL;
668   case Attribute::NoRedZone:
669     return bitc::ATTR_KIND_NO_RED_ZONE;
670   case Attribute::NoReturn:
671     return bitc::ATTR_KIND_NO_RETURN;
672   case Attribute::NoSync:
673     return bitc::ATTR_KIND_NOSYNC;
674   case Attribute::NoCfCheck:
675     return bitc::ATTR_KIND_NOCF_CHECK;
676   case Attribute::NoUnwind:
677     return bitc::ATTR_KIND_NO_UNWIND;
678   case Attribute::NullPointerIsValid:
679     return bitc::ATTR_KIND_NULL_POINTER_IS_VALID;
680   case Attribute::OptForFuzzing:
681     return bitc::ATTR_KIND_OPT_FOR_FUZZING;
682   case Attribute::OptimizeForSize:
683     return bitc::ATTR_KIND_OPTIMIZE_FOR_SIZE;
684   case Attribute::OptimizeNone:
685     return bitc::ATTR_KIND_OPTIMIZE_NONE;
686   case Attribute::ReadNone:
687     return bitc::ATTR_KIND_READ_NONE;
688   case Attribute::ReadOnly:
689     return bitc::ATTR_KIND_READ_ONLY;
690   case Attribute::Returned:
691     return bitc::ATTR_KIND_RETURNED;
692   case Attribute::ReturnsTwice:
693     return bitc::ATTR_KIND_RETURNS_TWICE;
694   case Attribute::SExt:
695     return bitc::ATTR_KIND_S_EXT;
696   case Attribute::Speculatable:
697     return bitc::ATTR_KIND_SPECULATABLE;
698   case Attribute::StackAlignment:
699     return bitc::ATTR_KIND_STACK_ALIGNMENT;
700   case Attribute::StackProtect:
701     return bitc::ATTR_KIND_STACK_PROTECT;
702   case Attribute::StackProtectReq:
703     return bitc::ATTR_KIND_STACK_PROTECT_REQ;
704   case Attribute::StackProtectStrong:
705     return bitc::ATTR_KIND_STACK_PROTECT_STRONG;
706   case Attribute::SafeStack:
707     return bitc::ATTR_KIND_SAFESTACK;
708   case Attribute::ShadowCallStack:
709     return bitc::ATTR_KIND_SHADOWCALLSTACK;
710   case Attribute::StrictFP:
711     return bitc::ATTR_KIND_STRICT_FP;
712   case Attribute::StructRet:
713     return bitc::ATTR_KIND_STRUCT_RET;
714   case Attribute::SanitizeAddress:
715     return bitc::ATTR_KIND_SANITIZE_ADDRESS;
716   case Attribute::SanitizeHWAddress:
717     return bitc::ATTR_KIND_SANITIZE_HWADDRESS;
718   case Attribute::SanitizeThread:
719     return bitc::ATTR_KIND_SANITIZE_THREAD;
720   case Attribute::SanitizeMemory:
721     return bitc::ATTR_KIND_SANITIZE_MEMORY;
722   case Attribute::SpeculativeLoadHardening:
723     return bitc::ATTR_KIND_SPECULATIVE_LOAD_HARDENING;
724   case Attribute::SwiftError:
725     return bitc::ATTR_KIND_SWIFT_ERROR;
726   case Attribute::SwiftSelf:
727     return bitc::ATTR_KIND_SWIFT_SELF;
728   case Attribute::UWTable:
729     return bitc::ATTR_KIND_UW_TABLE;
730   case Attribute::WillReturn:
731     return bitc::ATTR_KIND_WILLRETURN;
732   case Attribute::WriteOnly:
733     return bitc::ATTR_KIND_WRITEONLY;
734   case Attribute::ZExt:
735     return bitc::ATTR_KIND_Z_EXT;
736   case Attribute::ImmArg:
737     return bitc::ATTR_KIND_IMMARG;
738   case Attribute::SanitizeMemTag:
739     return bitc::ATTR_KIND_SANITIZE_MEMTAG;
740   case Attribute::Preallocated:
741     return bitc::ATTR_KIND_PREALLOCATED;
742   case Attribute::NoUndef:
743     return bitc::ATTR_KIND_NOUNDEF;
744   case Attribute::ByRef:
745     return bitc::ATTR_KIND_BYREF;
746   case Attribute::EndAttrKinds:
747     llvm_unreachable("Can not encode end-attribute kinds marker.");
748   case Attribute::None:
749     llvm_unreachable("Can not encode none-attribute.");
750   case Attribute::EmptyKey:
751   case Attribute::TombstoneKey:
752     llvm_unreachable("Trying to encode EmptyKey/TombstoneKey");
753   }
754 
755   llvm_unreachable("Trying to encode unknown attribute");
756 }
757 
758 void ModuleBitcodeWriter::writeAttributeGroupTable() {
759   const std::vector<ValueEnumerator::IndexAndAttrSet> &AttrGrps =
760       VE.getAttributeGroups();
761   if (AttrGrps.empty()) return;
762 
763   Stream.EnterSubblock(bitc::PARAMATTR_GROUP_BLOCK_ID, 3);
764 
765   SmallVector<uint64_t, 64> Record;
766   for (ValueEnumerator::IndexAndAttrSet Pair : AttrGrps) {
767     unsigned AttrListIndex = Pair.first;
768     AttributeSet AS = Pair.second;
769     Record.push_back(VE.getAttributeGroupID(Pair));
770     Record.push_back(AttrListIndex);
771 
772     for (Attribute Attr : AS) {
773       if (Attr.isEnumAttribute()) {
774         Record.push_back(0);
775         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
776       } else if (Attr.isIntAttribute()) {
777         Record.push_back(1);
778         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
779         Record.push_back(Attr.getValueAsInt());
780       } else if (Attr.isStringAttribute()) {
781         StringRef Kind = Attr.getKindAsString();
782         StringRef Val = Attr.getValueAsString();
783 
784         Record.push_back(Val.empty() ? 3 : 4);
785         Record.append(Kind.begin(), Kind.end());
786         Record.push_back(0);
787         if (!Val.empty()) {
788           Record.append(Val.begin(), Val.end());
789           Record.push_back(0);
790         }
791       } else {
792         assert(Attr.isTypeAttribute());
793         Type *Ty = Attr.getValueAsType();
794         Record.push_back(Ty ? 6 : 5);
795         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
796         if (Ty)
797           Record.push_back(VE.getTypeID(Attr.getValueAsType()));
798       }
799     }
800 
801     Stream.EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
802     Record.clear();
803   }
804 
805   Stream.ExitBlock();
806 }
807 
808 void ModuleBitcodeWriter::writeAttributeTable() {
809   const std::vector<AttributeList> &Attrs = VE.getAttributeLists();
810   if (Attrs.empty()) return;
811 
812   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
813 
814   SmallVector<uint64_t, 64> Record;
815   for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
816     AttributeList AL = Attrs[i];
817     for (unsigned i = AL.index_begin(), e = AL.index_end(); i != e; ++i) {
818       AttributeSet AS = AL.getAttributes(i);
819       if (AS.hasAttributes())
820         Record.push_back(VE.getAttributeGroupID({i, AS}));
821     }
822 
823     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
824     Record.clear();
825   }
826 
827   Stream.ExitBlock();
828 }
829 
830 /// WriteTypeTable - Write out the type table for a module.
831 void ModuleBitcodeWriter::writeTypeTable() {
832   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
833 
834   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
835   SmallVector<uint64_t, 64> TypeVals;
836 
837   uint64_t NumBits = VE.computeBitsRequiredForTypeIndicies();
838 
839   // Abbrev for TYPE_CODE_POINTER.
840   auto Abbv = std::make_shared<BitCodeAbbrev>();
841   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
842   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
843   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
844   unsigned PtrAbbrev = Stream.EmitAbbrev(std::move(Abbv));
845 
846   // Abbrev for TYPE_CODE_FUNCTION.
847   Abbv = std::make_shared<BitCodeAbbrev>();
848   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
849   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
850   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
851   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
852   unsigned FunctionAbbrev = Stream.EmitAbbrev(std::move(Abbv));
853 
854   // Abbrev for TYPE_CODE_STRUCT_ANON.
855   Abbv = std::make_shared<BitCodeAbbrev>();
856   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
857   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
858   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
859   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
860   unsigned StructAnonAbbrev = Stream.EmitAbbrev(std::move(Abbv));
861 
862   // Abbrev for TYPE_CODE_STRUCT_NAME.
863   Abbv = std::make_shared<BitCodeAbbrev>();
864   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
865   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
866   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
867   unsigned StructNameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
868 
869   // Abbrev for TYPE_CODE_STRUCT_NAMED.
870   Abbv = std::make_shared<BitCodeAbbrev>();
871   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
872   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
873   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
874   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
875   unsigned StructNamedAbbrev = Stream.EmitAbbrev(std::move(Abbv));
876 
877   // Abbrev for TYPE_CODE_ARRAY.
878   Abbv = std::make_shared<BitCodeAbbrev>();
879   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
880   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
881   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
882   unsigned ArrayAbbrev = Stream.EmitAbbrev(std::move(Abbv));
883 
884   // Emit an entry count so the reader can reserve space.
885   TypeVals.push_back(TypeList.size());
886   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
887   TypeVals.clear();
888 
889   // Loop over all of the types, emitting each in turn.
890   for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
891     Type *T = TypeList[i];
892     int AbbrevToUse = 0;
893     unsigned Code = 0;
894 
895     switch (T->getTypeID()) {
896     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;      break;
897     case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;      break;
898     case Type::BFloatTyID:    Code = bitc::TYPE_CODE_BFLOAT;    break;
899     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;     break;
900     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE;    break;
901     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80;  break;
902     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128;     break;
903     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
904     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;     break;
905     case Type::MetadataTyID:  Code = bitc::TYPE_CODE_METADATA;  break;
906     case Type::X86_MMXTyID:   Code = bitc::TYPE_CODE_X86_MMX;   break;
907     case Type::TokenTyID:     Code = bitc::TYPE_CODE_TOKEN;     break;
908     case Type::IntegerTyID:
909       // INTEGER: [width]
910       Code = bitc::TYPE_CODE_INTEGER;
911       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
912       break;
913     case Type::PointerTyID: {
914       PointerType *PTy = cast<PointerType>(T);
915       // POINTER: [pointee type, address space]
916       Code = bitc::TYPE_CODE_POINTER;
917       TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
918       unsigned AddressSpace = PTy->getAddressSpace();
919       TypeVals.push_back(AddressSpace);
920       if (AddressSpace == 0) AbbrevToUse = PtrAbbrev;
921       break;
922     }
923     case Type::FunctionTyID: {
924       FunctionType *FT = cast<FunctionType>(T);
925       // FUNCTION: [isvararg, retty, paramty x N]
926       Code = bitc::TYPE_CODE_FUNCTION;
927       TypeVals.push_back(FT->isVarArg());
928       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
929       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
930         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
931       AbbrevToUse = FunctionAbbrev;
932       break;
933     }
934     case Type::StructTyID: {
935       StructType *ST = cast<StructType>(T);
936       // STRUCT: [ispacked, eltty x N]
937       TypeVals.push_back(ST->isPacked());
938       // Output all of the element types.
939       for (StructType::element_iterator I = ST->element_begin(),
940            E = ST->element_end(); I != E; ++I)
941         TypeVals.push_back(VE.getTypeID(*I));
942 
943       if (ST->isLiteral()) {
944         Code = bitc::TYPE_CODE_STRUCT_ANON;
945         AbbrevToUse = StructAnonAbbrev;
946       } else {
947         if (ST->isOpaque()) {
948           Code = bitc::TYPE_CODE_OPAQUE;
949         } else {
950           Code = bitc::TYPE_CODE_STRUCT_NAMED;
951           AbbrevToUse = StructNamedAbbrev;
952         }
953 
954         // Emit the name if it is present.
955         if (!ST->getName().empty())
956           writeStringRecord(Stream, bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
957                             StructNameAbbrev);
958       }
959       break;
960     }
961     case Type::ArrayTyID: {
962       ArrayType *AT = cast<ArrayType>(T);
963       // ARRAY: [numelts, eltty]
964       Code = bitc::TYPE_CODE_ARRAY;
965       TypeVals.push_back(AT->getNumElements());
966       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
967       AbbrevToUse = ArrayAbbrev;
968       break;
969     }
970     case Type::FixedVectorTyID:
971     case Type::ScalableVectorTyID: {
972       VectorType *VT = cast<VectorType>(T);
973       // VECTOR [numelts, eltty] or
974       //        [numelts, eltty, scalable]
975       Code = bitc::TYPE_CODE_VECTOR;
976       TypeVals.push_back(VT->getElementCount().getKnownMinValue());
977       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
978       if (isa<ScalableVectorType>(VT))
979         TypeVals.push_back(true);
980       break;
981     }
982     }
983 
984     // Emit the finished record.
985     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
986     TypeVals.clear();
987   }
988 
989   Stream.ExitBlock();
990 }
991 
992 static unsigned getEncodedLinkage(const GlobalValue::LinkageTypes Linkage) {
993   switch (Linkage) {
994   case GlobalValue::ExternalLinkage:
995     return 0;
996   case GlobalValue::WeakAnyLinkage:
997     return 16;
998   case GlobalValue::AppendingLinkage:
999     return 2;
1000   case GlobalValue::InternalLinkage:
1001     return 3;
1002   case GlobalValue::LinkOnceAnyLinkage:
1003     return 18;
1004   case GlobalValue::ExternalWeakLinkage:
1005     return 7;
1006   case GlobalValue::CommonLinkage:
1007     return 8;
1008   case GlobalValue::PrivateLinkage:
1009     return 9;
1010   case GlobalValue::WeakODRLinkage:
1011     return 17;
1012   case GlobalValue::LinkOnceODRLinkage:
1013     return 19;
1014   case GlobalValue::AvailableExternallyLinkage:
1015     return 12;
1016   }
1017   llvm_unreachable("Invalid linkage");
1018 }
1019 
1020 static unsigned getEncodedLinkage(const GlobalValue &GV) {
1021   return getEncodedLinkage(GV.getLinkage());
1022 }
1023 
1024 static uint64_t getEncodedFFlags(FunctionSummary::FFlags Flags) {
1025   uint64_t RawFlags = 0;
1026   RawFlags |= Flags.ReadNone;
1027   RawFlags |= (Flags.ReadOnly << 1);
1028   RawFlags |= (Flags.NoRecurse << 2);
1029   RawFlags |= (Flags.ReturnDoesNotAlias << 3);
1030   RawFlags |= (Flags.NoInline << 4);
1031   RawFlags |= (Flags.AlwaysInline << 5);
1032   return RawFlags;
1033 }
1034 
1035 // Decode the flags for GlobalValue in the summary
1036 static uint64_t getEncodedGVSummaryFlags(GlobalValueSummary::GVFlags Flags) {
1037   uint64_t RawFlags = 0;
1038 
1039   RawFlags |= Flags.NotEligibleToImport; // bool
1040   RawFlags |= (Flags.Live << 1);
1041   RawFlags |= (Flags.DSOLocal << 2);
1042   RawFlags |= (Flags.CanAutoHide << 3);
1043 
1044   // Linkage don't need to be remapped at that time for the summary. Any future
1045   // change to the getEncodedLinkage() function will need to be taken into
1046   // account here as well.
1047   RawFlags = (RawFlags << 4) | Flags.Linkage; // 4 bits
1048 
1049   return RawFlags;
1050 }
1051 
1052 static uint64_t getEncodedGVarFlags(GlobalVarSummary::GVarFlags Flags) {
1053   uint64_t RawFlags = Flags.MaybeReadOnly | (Flags.MaybeWriteOnly << 1) |
1054                       (Flags.Constant << 2) | Flags.VCallVisibility << 3;
1055   return RawFlags;
1056 }
1057 
1058 static unsigned getEncodedVisibility(const GlobalValue &GV) {
1059   switch (GV.getVisibility()) {
1060   case GlobalValue::DefaultVisibility:   return 0;
1061   case GlobalValue::HiddenVisibility:    return 1;
1062   case GlobalValue::ProtectedVisibility: return 2;
1063   }
1064   llvm_unreachable("Invalid visibility");
1065 }
1066 
1067 static unsigned getEncodedDLLStorageClass(const GlobalValue &GV) {
1068   switch (GV.getDLLStorageClass()) {
1069   case GlobalValue::DefaultStorageClass:   return 0;
1070   case GlobalValue::DLLImportStorageClass: return 1;
1071   case GlobalValue::DLLExportStorageClass: return 2;
1072   }
1073   llvm_unreachable("Invalid DLL storage class");
1074 }
1075 
1076 static unsigned getEncodedThreadLocalMode(const GlobalValue &GV) {
1077   switch (GV.getThreadLocalMode()) {
1078     case GlobalVariable::NotThreadLocal:         return 0;
1079     case GlobalVariable::GeneralDynamicTLSModel: return 1;
1080     case GlobalVariable::LocalDynamicTLSModel:   return 2;
1081     case GlobalVariable::InitialExecTLSModel:    return 3;
1082     case GlobalVariable::LocalExecTLSModel:      return 4;
1083   }
1084   llvm_unreachable("Invalid TLS model");
1085 }
1086 
1087 static unsigned getEncodedComdatSelectionKind(const Comdat &C) {
1088   switch (C.getSelectionKind()) {
1089   case Comdat::Any:
1090     return bitc::COMDAT_SELECTION_KIND_ANY;
1091   case Comdat::ExactMatch:
1092     return bitc::COMDAT_SELECTION_KIND_EXACT_MATCH;
1093   case Comdat::Largest:
1094     return bitc::COMDAT_SELECTION_KIND_LARGEST;
1095   case Comdat::NoDuplicates:
1096     return bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES;
1097   case Comdat::SameSize:
1098     return bitc::COMDAT_SELECTION_KIND_SAME_SIZE;
1099   }
1100   llvm_unreachable("Invalid selection kind");
1101 }
1102 
1103 static unsigned getEncodedUnnamedAddr(const GlobalValue &GV) {
1104   switch (GV.getUnnamedAddr()) {
1105   case GlobalValue::UnnamedAddr::None:   return 0;
1106   case GlobalValue::UnnamedAddr::Local:  return 2;
1107   case GlobalValue::UnnamedAddr::Global: return 1;
1108   }
1109   llvm_unreachable("Invalid unnamed_addr");
1110 }
1111 
1112 size_t ModuleBitcodeWriter::addToStrtab(StringRef Str) {
1113   if (GenerateHash)
1114     Hasher.update(Str);
1115   return StrtabBuilder.add(Str);
1116 }
1117 
1118 void ModuleBitcodeWriter::writeComdats() {
1119   SmallVector<unsigned, 64> Vals;
1120   for (const Comdat *C : VE.getComdats()) {
1121     // COMDAT: [strtab offset, strtab size, selection_kind]
1122     Vals.push_back(addToStrtab(C->getName()));
1123     Vals.push_back(C->getName().size());
1124     Vals.push_back(getEncodedComdatSelectionKind(*C));
1125     Stream.EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
1126     Vals.clear();
1127   }
1128 }
1129 
1130 /// Write a record that will eventually hold the word offset of the
1131 /// module-level VST. For now the offset is 0, which will be backpatched
1132 /// after the real VST is written. Saves the bit offset to backpatch.
1133 void ModuleBitcodeWriter::writeValueSymbolTableForwardDecl() {
1134   // Write a placeholder value in for the offset of the real VST,
1135   // which is written after the function blocks so that it can include
1136   // the offset of each function. The placeholder offset will be
1137   // updated when the real VST is written.
1138   auto Abbv = std::make_shared<BitCodeAbbrev>();
1139   Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_VSTOFFSET));
1140   // Blocks are 32-bit aligned, so we can use a 32-bit word offset to
1141   // hold the real VST offset. Must use fixed instead of VBR as we don't
1142   // know how many VBR chunks to reserve ahead of time.
1143   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
1144   unsigned VSTOffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1145 
1146   // Emit the placeholder
1147   uint64_t Vals[] = {bitc::MODULE_CODE_VSTOFFSET, 0};
1148   Stream.EmitRecordWithAbbrev(VSTOffsetAbbrev, Vals);
1149 
1150   // Compute and save the bit offset to the placeholder, which will be
1151   // patched when the real VST is written. We can simply subtract the 32-bit
1152   // fixed size from the current bit number to get the location to backpatch.
1153   VSTOffsetPlaceholder = Stream.GetCurrentBitNo() - 32;
1154 }
1155 
1156 enum StringEncoding { SE_Char6, SE_Fixed7, SE_Fixed8 };
1157 
1158 /// Determine the encoding to use for the given string name and length.
1159 static StringEncoding getStringEncoding(StringRef Str) {
1160   bool isChar6 = true;
1161   for (char C : Str) {
1162     if (isChar6)
1163       isChar6 = BitCodeAbbrevOp::isChar6(C);
1164     if ((unsigned char)C & 128)
1165       // don't bother scanning the rest.
1166       return SE_Fixed8;
1167   }
1168   if (isChar6)
1169     return SE_Char6;
1170   return SE_Fixed7;
1171 }
1172 
1173 /// Emit top-level description of module, including target triple, inline asm,
1174 /// descriptors for global variables, and function prototype info.
1175 /// Returns the bit offset to backpatch with the location of the real VST.
1176 void ModuleBitcodeWriter::writeModuleInfo() {
1177   // Emit various pieces of data attached to a module.
1178   if (!M.getTargetTriple().empty())
1179     writeStringRecord(Stream, bitc::MODULE_CODE_TRIPLE, M.getTargetTriple(),
1180                       0 /*TODO*/);
1181   const std::string &DL = M.getDataLayoutStr();
1182   if (!DL.empty())
1183     writeStringRecord(Stream, bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/);
1184   if (!M.getModuleInlineAsm().empty())
1185     writeStringRecord(Stream, bitc::MODULE_CODE_ASM, M.getModuleInlineAsm(),
1186                       0 /*TODO*/);
1187 
1188   // Emit information about sections and GC, computing how many there are. Also
1189   // compute the maximum alignment value.
1190   std::map<std::string, unsigned> SectionMap;
1191   std::map<std::string, unsigned> GCMap;
1192   MaybeAlign MaxAlignment;
1193   unsigned MaxGlobalType = 0;
1194   const auto UpdateMaxAlignment = [&MaxAlignment](const MaybeAlign A) {
1195     if (A)
1196       MaxAlignment = !MaxAlignment ? *A : std::max(*MaxAlignment, *A);
1197   };
1198   for (const GlobalVariable &GV : M.globals()) {
1199     UpdateMaxAlignment(GV.getAlign());
1200     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getValueType()));
1201     if (GV.hasSection()) {
1202       // Give section names unique ID's.
1203       unsigned &Entry = SectionMap[std::string(GV.getSection())];
1204       if (!Entry) {
1205         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
1206                           0 /*TODO*/);
1207         Entry = SectionMap.size();
1208       }
1209     }
1210   }
1211   for (const Function &F : M) {
1212     UpdateMaxAlignment(F.getAlign());
1213     if (F.hasSection()) {
1214       // Give section names unique ID's.
1215       unsigned &Entry = SectionMap[std::string(F.getSection())];
1216       if (!Entry) {
1217         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
1218                           0 /*TODO*/);
1219         Entry = SectionMap.size();
1220       }
1221     }
1222     if (F.hasGC()) {
1223       // Same for GC names.
1224       unsigned &Entry = GCMap[F.getGC()];
1225       if (!Entry) {
1226         writeStringRecord(Stream, bitc::MODULE_CODE_GCNAME, F.getGC(),
1227                           0 /*TODO*/);
1228         Entry = GCMap.size();
1229       }
1230     }
1231   }
1232 
1233   // Emit abbrev for globals, now that we know # sections and max alignment.
1234   unsigned SimpleGVarAbbrev = 0;
1235   if (!M.global_empty()) {
1236     // Add an abbrev for common globals with no visibility or thread localness.
1237     auto Abbv = std::make_shared<BitCodeAbbrev>();
1238     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
1239     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1240     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1241     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1242                               Log2_32_Ceil(MaxGlobalType+1)));
1243     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddrSpace << 2
1244                                                            //| explicitType << 1
1245                                                            //| constant
1246     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Initializer.
1247     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // Linkage.
1248     if (!MaxAlignment)                                     // Alignment.
1249       Abbv->Add(BitCodeAbbrevOp(0));
1250     else {
1251       unsigned MaxEncAlignment = getEncodedAlign(MaxAlignment);
1252       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1253                                Log2_32_Ceil(MaxEncAlignment+1)));
1254     }
1255     if (SectionMap.empty())                                    // Section.
1256       Abbv->Add(BitCodeAbbrevOp(0));
1257     else
1258       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1259                                Log2_32_Ceil(SectionMap.size()+1)));
1260     // Don't bother emitting vis + thread local.
1261     SimpleGVarAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1262   }
1263 
1264   SmallVector<unsigned, 64> Vals;
1265   // Emit the module's source file name.
1266   {
1267     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
1268     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
1269     if (Bits == SE_Char6)
1270       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
1271     else if (Bits == SE_Fixed7)
1272       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
1273 
1274     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
1275     auto Abbv = std::make_shared<BitCodeAbbrev>();
1276     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
1277     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1278     Abbv->Add(AbbrevOpToUse);
1279     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1280 
1281     for (const auto P : M.getSourceFileName())
1282       Vals.push_back((unsigned char)P);
1283 
1284     // Emit the finished record.
1285     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
1286     Vals.clear();
1287   }
1288 
1289   // Emit the global variable information.
1290   for (const GlobalVariable &GV : M.globals()) {
1291     unsigned AbbrevToUse = 0;
1292 
1293     // GLOBALVAR: [strtab offset, strtab size, type, isconst, initid,
1294     //             linkage, alignment, section, visibility, threadlocal,
1295     //             unnamed_addr, externally_initialized, dllstorageclass,
1296     //             comdat, attributes, DSO_Local]
1297     Vals.push_back(addToStrtab(GV.getName()));
1298     Vals.push_back(GV.getName().size());
1299     Vals.push_back(VE.getTypeID(GV.getValueType()));
1300     Vals.push_back(GV.getType()->getAddressSpace() << 2 | 2 | GV.isConstant());
1301     Vals.push_back(GV.isDeclaration() ? 0 :
1302                    (VE.getValueID(GV.getInitializer()) + 1));
1303     Vals.push_back(getEncodedLinkage(GV));
1304     Vals.push_back(getEncodedAlign(GV.getAlign()));
1305     Vals.push_back(GV.hasSection() ? SectionMap[std::string(GV.getSection())]
1306                                    : 0);
1307     if (GV.isThreadLocal() ||
1308         GV.getVisibility() != GlobalValue::DefaultVisibility ||
1309         GV.getUnnamedAddr() != GlobalValue::UnnamedAddr::None ||
1310         GV.isExternallyInitialized() ||
1311         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
1312         GV.hasComdat() ||
1313         GV.hasAttributes() ||
1314         GV.isDSOLocal() ||
1315         GV.hasPartition()) {
1316       Vals.push_back(getEncodedVisibility(GV));
1317       Vals.push_back(getEncodedThreadLocalMode(GV));
1318       Vals.push_back(getEncodedUnnamedAddr(GV));
1319       Vals.push_back(GV.isExternallyInitialized());
1320       Vals.push_back(getEncodedDLLStorageClass(GV));
1321       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
1322 
1323       auto AL = GV.getAttributesAsList(AttributeList::FunctionIndex);
1324       Vals.push_back(VE.getAttributeListID(AL));
1325 
1326       Vals.push_back(GV.isDSOLocal());
1327       Vals.push_back(addToStrtab(GV.getPartition()));
1328       Vals.push_back(GV.getPartition().size());
1329     } else {
1330       AbbrevToUse = SimpleGVarAbbrev;
1331     }
1332 
1333     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
1334     Vals.clear();
1335   }
1336 
1337   // Emit the function proto information.
1338   for (const Function &F : M) {
1339     // FUNCTION:  [strtab offset, strtab size, type, callingconv, isproto,
1340     //             linkage, paramattrs, alignment, section, visibility, gc,
1341     //             unnamed_addr, prologuedata, dllstorageclass, comdat,
1342     //             prefixdata, personalityfn, DSO_Local, addrspace]
1343     Vals.push_back(addToStrtab(F.getName()));
1344     Vals.push_back(F.getName().size());
1345     Vals.push_back(VE.getTypeID(F.getFunctionType()));
1346     Vals.push_back(F.getCallingConv());
1347     Vals.push_back(F.isDeclaration());
1348     Vals.push_back(getEncodedLinkage(F));
1349     Vals.push_back(VE.getAttributeListID(F.getAttributes()));
1350     Vals.push_back(getEncodedAlign(F.getAlign()));
1351     Vals.push_back(F.hasSection() ? SectionMap[std::string(F.getSection())]
1352                                   : 0);
1353     Vals.push_back(getEncodedVisibility(F));
1354     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
1355     Vals.push_back(getEncodedUnnamedAddr(F));
1356     Vals.push_back(F.hasPrologueData() ? (VE.getValueID(F.getPrologueData()) + 1)
1357                                        : 0);
1358     Vals.push_back(getEncodedDLLStorageClass(F));
1359     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
1360     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
1361                                      : 0);
1362     Vals.push_back(
1363         F.hasPersonalityFn() ? (VE.getValueID(F.getPersonalityFn()) + 1) : 0);
1364 
1365     Vals.push_back(F.isDSOLocal());
1366     Vals.push_back(F.getAddressSpace());
1367     Vals.push_back(addToStrtab(F.getPartition()));
1368     Vals.push_back(F.getPartition().size());
1369 
1370     unsigned AbbrevToUse = 0;
1371     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
1372     Vals.clear();
1373   }
1374 
1375   // Emit the alias information.
1376   for (const GlobalAlias &A : M.aliases()) {
1377     // ALIAS: [strtab offset, strtab size, alias type, aliasee val#, linkage,
1378     //         visibility, dllstorageclass, threadlocal, unnamed_addr,
1379     //         DSO_Local]
1380     Vals.push_back(addToStrtab(A.getName()));
1381     Vals.push_back(A.getName().size());
1382     Vals.push_back(VE.getTypeID(A.getValueType()));
1383     Vals.push_back(A.getType()->getAddressSpace());
1384     Vals.push_back(VE.getValueID(A.getAliasee()));
1385     Vals.push_back(getEncodedLinkage(A));
1386     Vals.push_back(getEncodedVisibility(A));
1387     Vals.push_back(getEncodedDLLStorageClass(A));
1388     Vals.push_back(getEncodedThreadLocalMode(A));
1389     Vals.push_back(getEncodedUnnamedAddr(A));
1390     Vals.push_back(A.isDSOLocal());
1391     Vals.push_back(addToStrtab(A.getPartition()));
1392     Vals.push_back(A.getPartition().size());
1393 
1394     unsigned AbbrevToUse = 0;
1395     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
1396     Vals.clear();
1397   }
1398 
1399   // Emit the ifunc information.
1400   for (const GlobalIFunc &I : M.ifuncs()) {
1401     // IFUNC: [strtab offset, strtab size, ifunc type, address space, resolver
1402     //         val#, linkage, visibility, DSO_Local]
1403     Vals.push_back(addToStrtab(I.getName()));
1404     Vals.push_back(I.getName().size());
1405     Vals.push_back(VE.getTypeID(I.getValueType()));
1406     Vals.push_back(I.getType()->getAddressSpace());
1407     Vals.push_back(VE.getValueID(I.getResolver()));
1408     Vals.push_back(getEncodedLinkage(I));
1409     Vals.push_back(getEncodedVisibility(I));
1410     Vals.push_back(I.isDSOLocal());
1411     Vals.push_back(addToStrtab(I.getPartition()));
1412     Vals.push_back(I.getPartition().size());
1413     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
1414     Vals.clear();
1415   }
1416 
1417   writeValueSymbolTableForwardDecl();
1418 }
1419 
1420 static uint64_t getOptimizationFlags(const Value *V) {
1421   uint64_t Flags = 0;
1422 
1423   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
1424     if (OBO->hasNoSignedWrap())
1425       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
1426     if (OBO->hasNoUnsignedWrap())
1427       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
1428   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
1429     if (PEO->isExact())
1430       Flags |= 1 << bitc::PEO_EXACT;
1431   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
1432     if (FPMO->hasAllowReassoc())
1433       Flags |= bitc::AllowReassoc;
1434     if (FPMO->hasNoNaNs())
1435       Flags |= bitc::NoNaNs;
1436     if (FPMO->hasNoInfs())
1437       Flags |= bitc::NoInfs;
1438     if (FPMO->hasNoSignedZeros())
1439       Flags |= bitc::NoSignedZeros;
1440     if (FPMO->hasAllowReciprocal())
1441       Flags |= bitc::AllowReciprocal;
1442     if (FPMO->hasAllowContract())
1443       Flags |= bitc::AllowContract;
1444     if (FPMO->hasApproxFunc())
1445       Flags |= bitc::ApproxFunc;
1446   }
1447 
1448   return Flags;
1449 }
1450 
1451 void ModuleBitcodeWriter::writeValueAsMetadata(
1452     const ValueAsMetadata *MD, SmallVectorImpl<uint64_t> &Record) {
1453   // Mimic an MDNode with a value as one operand.
1454   Value *V = MD->getValue();
1455   Record.push_back(VE.getTypeID(V->getType()));
1456   Record.push_back(VE.getValueID(V));
1457   Stream.EmitRecord(bitc::METADATA_VALUE, Record, 0);
1458   Record.clear();
1459 }
1460 
1461 void ModuleBitcodeWriter::writeMDTuple(const MDTuple *N,
1462                                        SmallVectorImpl<uint64_t> &Record,
1463                                        unsigned Abbrev) {
1464   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
1465     Metadata *MD = N->getOperand(i);
1466     assert(!(MD && isa<LocalAsMetadata>(MD)) &&
1467            "Unexpected function-local metadata");
1468     Record.push_back(VE.getMetadataOrNullID(MD));
1469   }
1470   Stream.EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
1471                                     : bitc::METADATA_NODE,
1472                     Record, Abbrev);
1473   Record.clear();
1474 }
1475 
1476 unsigned ModuleBitcodeWriter::createDILocationAbbrev() {
1477   // Assume the column is usually under 128, and always output the inlined-at
1478   // location (it's never more expensive than building an array size 1).
1479   auto Abbv = std::make_shared<BitCodeAbbrev>();
1480   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
1481   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1482   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1483   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1484   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1485   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1486   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1487   return Stream.EmitAbbrev(std::move(Abbv));
1488 }
1489 
1490 void ModuleBitcodeWriter::writeDILocation(const DILocation *N,
1491                                           SmallVectorImpl<uint64_t> &Record,
1492                                           unsigned &Abbrev) {
1493   if (!Abbrev)
1494     Abbrev = createDILocationAbbrev();
1495 
1496   Record.push_back(N->isDistinct());
1497   Record.push_back(N->getLine());
1498   Record.push_back(N->getColumn());
1499   Record.push_back(VE.getMetadataID(N->getScope()));
1500   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
1501   Record.push_back(N->isImplicitCode());
1502 
1503   Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
1504   Record.clear();
1505 }
1506 
1507 unsigned ModuleBitcodeWriter::createGenericDINodeAbbrev() {
1508   // Assume the column is usually under 128, and always output the inlined-at
1509   // location (it's never more expensive than building an array size 1).
1510   auto Abbv = std::make_shared<BitCodeAbbrev>();
1511   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
1512   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1513   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1514   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1515   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1516   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1517   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1518   return Stream.EmitAbbrev(std::move(Abbv));
1519 }
1520 
1521 void ModuleBitcodeWriter::writeGenericDINode(const GenericDINode *N,
1522                                              SmallVectorImpl<uint64_t> &Record,
1523                                              unsigned &Abbrev) {
1524   if (!Abbrev)
1525     Abbrev = createGenericDINodeAbbrev();
1526 
1527   Record.push_back(N->isDistinct());
1528   Record.push_back(N->getTag());
1529   Record.push_back(0); // Per-tag version field; unused for now.
1530 
1531   for (auto &I : N->operands())
1532     Record.push_back(VE.getMetadataOrNullID(I));
1533 
1534   Stream.EmitRecord(bitc::METADATA_GENERIC_DEBUG, Record, Abbrev);
1535   Record.clear();
1536 }
1537 
1538 void ModuleBitcodeWriter::writeDISubrange(const DISubrange *N,
1539                                           SmallVectorImpl<uint64_t> &Record,
1540                                           unsigned Abbrev) {
1541   const uint64_t Version = 2 << 1;
1542   Record.push_back((uint64_t)N->isDistinct() | Version);
1543   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1544   Record.push_back(VE.getMetadataOrNullID(N->getRawLowerBound()));
1545   Record.push_back(VE.getMetadataOrNullID(N->getRawUpperBound()));
1546   Record.push_back(VE.getMetadataOrNullID(N->getRawStride()));
1547 
1548   Stream.EmitRecord(bitc::METADATA_SUBRANGE, Record, Abbrev);
1549   Record.clear();
1550 }
1551 
1552 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
1553   if ((int64_t)V >= 0)
1554     Vals.push_back(V << 1);
1555   else
1556     Vals.push_back((-V << 1) | 1);
1557 }
1558 
1559 static void emitWideAPInt(SmallVectorImpl<uint64_t> &Vals, const APInt &A) {
1560   // We have an arbitrary precision integer value to write whose
1561   // bit width is > 64. However, in canonical unsigned integer
1562   // format it is likely that the high bits are going to be zero.
1563   // So, we only write the number of active words.
1564   unsigned NumWords = A.getActiveWords();
1565   const uint64_t *RawData = A.getRawData();
1566   for (unsigned i = 0; i < NumWords; i++)
1567     emitSignedInt64(Vals, RawData[i]);
1568 }
1569 
1570 void ModuleBitcodeWriter::writeDIEnumerator(const DIEnumerator *N,
1571                                             SmallVectorImpl<uint64_t> &Record,
1572                                             unsigned Abbrev) {
1573   const uint64_t IsBigInt = 1 << 2;
1574   Record.push_back(IsBigInt | (N->isUnsigned() << 1) | N->isDistinct());
1575   Record.push_back(N->getValue().getBitWidth());
1576   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1577   emitWideAPInt(Record, N->getValue());
1578 
1579   Stream.EmitRecord(bitc::METADATA_ENUMERATOR, Record, Abbrev);
1580   Record.clear();
1581 }
1582 
1583 void ModuleBitcodeWriter::writeDIBasicType(const DIBasicType *N,
1584                                            SmallVectorImpl<uint64_t> &Record,
1585                                            unsigned Abbrev) {
1586   Record.push_back(N->isDistinct());
1587   Record.push_back(N->getTag());
1588   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1589   Record.push_back(N->getSizeInBits());
1590   Record.push_back(N->getAlignInBits());
1591   Record.push_back(N->getEncoding());
1592   Record.push_back(N->getFlags());
1593 
1594   Stream.EmitRecord(bitc::METADATA_BASIC_TYPE, Record, Abbrev);
1595   Record.clear();
1596 }
1597 
1598 void ModuleBitcodeWriter::writeDIStringType(const DIStringType *N,
1599                                             SmallVectorImpl<uint64_t> &Record,
1600                                             unsigned Abbrev) {
1601   Record.push_back(N->isDistinct());
1602   Record.push_back(N->getTag());
1603   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1604   Record.push_back(VE.getMetadataOrNullID(N->getStringLength()));
1605   Record.push_back(VE.getMetadataOrNullID(N->getStringLengthExp()));
1606   Record.push_back(N->getSizeInBits());
1607   Record.push_back(N->getAlignInBits());
1608   Record.push_back(N->getEncoding());
1609 
1610   Stream.EmitRecord(bitc::METADATA_STRING_TYPE, Record, Abbrev);
1611   Record.clear();
1612 }
1613 
1614 void ModuleBitcodeWriter::writeDIDerivedType(const DIDerivedType *N,
1615                                              SmallVectorImpl<uint64_t> &Record,
1616                                              unsigned Abbrev) {
1617   Record.push_back(N->isDistinct());
1618   Record.push_back(N->getTag());
1619   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1620   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1621   Record.push_back(N->getLine());
1622   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1623   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1624   Record.push_back(N->getSizeInBits());
1625   Record.push_back(N->getAlignInBits());
1626   Record.push_back(N->getOffsetInBits());
1627   Record.push_back(N->getFlags());
1628   Record.push_back(VE.getMetadataOrNullID(N->getExtraData()));
1629 
1630   // DWARF address space is encoded as N->getDWARFAddressSpace() + 1. 0 means
1631   // that there is no DWARF address space associated with DIDerivedType.
1632   if (const auto &DWARFAddressSpace = N->getDWARFAddressSpace())
1633     Record.push_back(*DWARFAddressSpace + 1);
1634   else
1635     Record.push_back(0);
1636 
1637   Stream.EmitRecord(bitc::METADATA_DERIVED_TYPE, Record, Abbrev);
1638   Record.clear();
1639 }
1640 
1641 void ModuleBitcodeWriter::writeDICompositeType(
1642     const DICompositeType *N, SmallVectorImpl<uint64_t> &Record,
1643     unsigned Abbrev) {
1644   const unsigned IsNotUsedInOldTypeRef = 0x2;
1645   Record.push_back(IsNotUsedInOldTypeRef | (unsigned)N->isDistinct());
1646   Record.push_back(N->getTag());
1647   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1648   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1649   Record.push_back(N->getLine());
1650   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1651   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1652   Record.push_back(N->getSizeInBits());
1653   Record.push_back(N->getAlignInBits());
1654   Record.push_back(N->getOffsetInBits());
1655   Record.push_back(N->getFlags());
1656   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1657   Record.push_back(N->getRuntimeLang());
1658   Record.push_back(VE.getMetadataOrNullID(N->getVTableHolder()));
1659   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1660   Record.push_back(VE.getMetadataOrNullID(N->getRawIdentifier()));
1661   Record.push_back(VE.getMetadataOrNullID(N->getDiscriminator()));
1662   Record.push_back(VE.getMetadataOrNullID(N->getRawDataLocation()));
1663   Record.push_back(VE.getMetadataOrNullID(N->getRawAssociated()));
1664   Record.push_back(VE.getMetadataOrNullID(N->getRawAllocated()));
1665 
1666   Stream.EmitRecord(bitc::METADATA_COMPOSITE_TYPE, Record, Abbrev);
1667   Record.clear();
1668 }
1669 
1670 void ModuleBitcodeWriter::writeDISubroutineType(
1671     const DISubroutineType *N, SmallVectorImpl<uint64_t> &Record,
1672     unsigned Abbrev) {
1673   const unsigned HasNoOldTypeRefs = 0x2;
1674   Record.push_back(HasNoOldTypeRefs | (unsigned)N->isDistinct());
1675   Record.push_back(N->getFlags());
1676   Record.push_back(VE.getMetadataOrNullID(N->getTypeArray().get()));
1677   Record.push_back(N->getCC());
1678 
1679   Stream.EmitRecord(bitc::METADATA_SUBROUTINE_TYPE, Record, Abbrev);
1680   Record.clear();
1681 }
1682 
1683 void ModuleBitcodeWriter::writeDIFile(const DIFile *N,
1684                                       SmallVectorImpl<uint64_t> &Record,
1685                                       unsigned Abbrev) {
1686   Record.push_back(N->isDistinct());
1687   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
1688   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
1689   if (N->getRawChecksum()) {
1690     Record.push_back(N->getRawChecksum()->Kind);
1691     Record.push_back(VE.getMetadataOrNullID(N->getRawChecksum()->Value));
1692   } else {
1693     // Maintain backwards compatibility with the old internal representation of
1694     // CSK_None in ChecksumKind by writing nulls here when Checksum is None.
1695     Record.push_back(0);
1696     Record.push_back(VE.getMetadataOrNullID(nullptr));
1697   }
1698   auto Source = N->getRawSource();
1699   if (Source)
1700     Record.push_back(VE.getMetadataOrNullID(*Source));
1701 
1702   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
1703   Record.clear();
1704 }
1705 
1706 void ModuleBitcodeWriter::writeDICompileUnit(const DICompileUnit *N,
1707                                              SmallVectorImpl<uint64_t> &Record,
1708                                              unsigned Abbrev) {
1709   assert(N->isDistinct() && "Expected distinct compile units");
1710   Record.push_back(/* IsDistinct */ true);
1711   Record.push_back(N->getSourceLanguage());
1712   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1713   Record.push_back(VE.getMetadataOrNullID(N->getRawProducer()));
1714   Record.push_back(N->isOptimized());
1715   Record.push_back(VE.getMetadataOrNullID(N->getRawFlags()));
1716   Record.push_back(N->getRuntimeVersion());
1717   Record.push_back(VE.getMetadataOrNullID(N->getRawSplitDebugFilename()));
1718   Record.push_back(N->getEmissionKind());
1719   Record.push_back(VE.getMetadataOrNullID(N->getEnumTypes().get()));
1720   Record.push_back(VE.getMetadataOrNullID(N->getRetainedTypes().get()));
1721   Record.push_back(/* subprograms */ 0);
1722   Record.push_back(VE.getMetadataOrNullID(N->getGlobalVariables().get()));
1723   Record.push_back(VE.getMetadataOrNullID(N->getImportedEntities().get()));
1724   Record.push_back(N->getDWOId());
1725   Record.push_back(VE.getMetadataOrNullID(N->getMacros().get()));
1726   Record.push_back(N->getSplitDebugInlining());
1727   Record.push_back(N->getDebugInfoForProfiling());
1728   Record.push_back((unsigned)N->getNameTableKind());
1729   Record.push_back(N->getRangesBaseAddress());
1730   Record.push_back(VE.getMetadataOrNullID(N->getRawSysRoot()));
1731   Record.push_back(VE.getMetadataOrNullID(N->getRawSDK()));
1732 
1733   Stream.EmitRecord(bitc::METADATA_COMPILE_UNIT, Record, Abbrev);
1734   Record.clear();
1735 }
1736 
1737 void ModuleBitcodeWriter::writeDISubprogram(const DISubprogram *N,
1738                                             SmallVectorImpl<uint64_t> &Record,
1739                                             unsigned Abbrev) {
1740   const uint64_t HasUnitFlag = 1 << 1;
1741   const uint64_t HasSPFlagsFlag = 1 << 2;
1742   Record.push_back(uint64_t(N->isDistinct()) | HasUnitFlag | HasSPFlagsFlag);
1743   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1744   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1745   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1746   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1747   Record.push_back(N->getLine());
1748   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1749   Record.push_back(N->getScopeLine());
1750   Record.push_back(VE.getMetadataOrNullID(N->getContainingType()));
1751   Record.push_back(N->getSPFlags());
1752   Record.push_back(N->getVirtualIndex());
1753   Record.push_back(N->getFlags());
1754   Record.push_back(VE.getMetadataOrNullID(N->getRawUnit()));
1755   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1756   Record.push_back(VE.getMetadataOrNullID(N->getDeclaration()));
1757   Record.push_back(VE.getMetadataOrNullID(N->getRetainedNodes().get()));
1758   Record.push_back(N->getThisAdjustment());
1759   Record.push_back(VE.getMetadataOrNullID(N->getThrownTypes().get()));
1760 
1761   Stream.EmitRecord(bitc::METADATA_SUBPROGRAM, Record, Abbrev);
1762   Record.clear();
1763 }
1764 
1765 void ModuleBitcodeWriter::writeDILexicalBlock(const DILexicalBlock *N,
1766                                               SmallVectorImpl<uint64_t> &Record,
1767                                               unsigned Abbrev) {
1768   Record.push_back(N->isDistinct());
1769   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1770   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1771   Record.push_back(N->getLine());
1772   Record.push_back(N->getColumn());
1773 
1774   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK, Record, Abbrev);
1775   Record.clear();
1776 }
1777 
1778 void ModuleBitcodeWriter::writeDILexicalBlockFile(
1779     const DILexicalBlockFile *N, SmallVectorImpl<uint64_t> &Record,
1780     unsigned Abbrev) {
1781   Record.push_back(N->isDistinct());
1782   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1783   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1784   Record.push_back(N->getDiscriminator());
1785 
1786   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK_FILE, Record, Abbrev);
1787   Record.clear();
1788 }
1789 
1790 void ModuleBitcodeWriter::writeDICommonBlock(const DICommonBlock *N,
1791                                              SmallVectorImpl<uint64_t> &Record,
1792                                              unsigned Abbrev) {
1793   Record.push_back(N->isDistinct());
1794   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1795   Record.push_back(VE.getMetadataOrNullID(N->getDecl()));
1796   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1797   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1798   Record.push_back(N->getLineNo());
1799 
1800   Stream.EmitRecord(bitc::METADATA_COMMON_BLOCK, Record, Abbrev);
1801   Record.clear();
1802 }
1803 
1804 void ModuleBitcodeWriter::writeDINamespace(const DINamespace *N,
1805                                            SmallVectorImpl<uint64_t> &Record,
1806                                            unsigned Abbrev) {
1807   Record.push_back(N->isDistinct() | N->getExportSymbols() << 1);
1808   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1809   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1810 
1811   Stream.EmitRecord(bitc::METADATA_NAMESPACE, Record, Abbrev);
1812   Record.clear();
1813 }
1814 
1815 void ModuleBitcodeWriter::writeDIMacro(const DIMacro *N,
1816                                        SmallVectorImpl<uint64_t> &Record,
1817                                        unsigned Abbrev) {
1818   Record.push_back(N->isDistinct());
1819   Record.push_back(N->getMacinfoType());
1820   Record.push_back(N->getLine());
1821   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1822   Record.push_back(VE.getMetadataOrNullID(N->getRawValue()));
1823 
1824   Stream.EmitRecord(bitc::METADATA_MACRO, Record, Abbrev);
1825   Record.clear();
1826 }
1827 
1828 void ModuleBitcodeWriter::writeDIMacroFile(const DIMacroFile *N,
1829                                            SmallVectorImpl<uint64_t> &Record,
1830                                            unsigned Abbrev) {
1831   Record.push_back(N->isDistinct());
1832   Record.push_back(N->getMacinfoType());
1833   Record.push_back(N->getLine());
1834   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1835   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1836 
1837   Stream.EmitRecord(bitc::METADATA_MACRO_FILE, Record, Abbrev);
1838   Record.clear();
1839 }
1840 
1841 void ModuleBitcodeWriter::writeDIModule(const DIModule *N,
1842                                         SmallVectorImpl<uint64_t> &Record,
1843                                         unsigned Abbrev) {
1844   Record.push_back(N->isDistinct());
1845   for (auto &I : N->operands())
1846     Record.push_back(VE.getMetadataOrNullID(I));
1847   Record.push_back(N->getLineNo());
1848 
1849   Stream.EmitRecord(bitc::METADATA_MODULE, Record, Abbrev);
1850   Record.clear();
1851 }
1852 
1853 void ModuleBitcodeWriter::writeDITemplateTypeParameter(
1854     const DITemplateTypeParameter *N, SmallVectorImpl<uint64_t> &Record,
1855     unsigned Abbrev) {
1856   Record.push_back(N->isDistinct());
1857   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1858   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1859   Record.push_back(N->isDefault());
1860 
1861   Stream.EmitRecord(bitc::METADATA_TEMPLATE_TYPE, Record, Abbrev);
1862   Record.clear();
1863 }
1864 
1865 void ModuleBitcodeWriter::writeDITemplateValueParameter(
1866     const DITemplateValueParameter *N, SmallVectorImpl<uint64_t> &Record,
1867     unsigned Abbrev) {
1868   Record.push_back(N->isDistinct());
1869   Record.push_back(N->getTag());
1870   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1871   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1872   Record.push_back(N->isDefault());
1873   Record.push_back(VE.getMetadataOrNullID(N->getValue()));
1874 
1875   Stream.EmitRecord(bitc::METADATA_TEMPLATE_VALUE, Record, Abbrev);
1876   Record.clear();
1877 }
1878 
1879 void ModuleBitcodeWriter::writeDIGlobalVariable(
1880     const DIGlobalVariable *N, SmallVectorImpl<uint64_t> &Record,
1881     unsigned Abbrev) {
1882   const uint64_t Version = 2 << 1;
1883   Record.push_back((uint64_t)N->isDistinct() | Version);
1884   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1885   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1886   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1887   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1888   Record.push_back(N->getLine());
1889   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1890   Record.push_back(N->isLocalToUnit());
1891   Record.push_back(N->isDefinition());
1892   Record.push_back(VE.getMetadataOrNullID(N->getStaticDataMemberDeclaration()));
1893   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams()));
1894   Record.push_back(N->getAlignInBits());
1895 
1896   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR, Record, Abbrev);
1897   Record.clear();
1898 }
1899 
1900 void ModuleBitcodeWriter::writeDILocalVariable(
1901     const DILocalVariable *N, SmallVectorImpl<uint64_t> &Record,
1902     unsigned Abbrev) {
1903   // In order to support all possible bitcode formats in BitcodeReader we need
1904   // to distinguish the following cases:
1905   // 1) Record has no artificial tag (Record[1]),
1906   //   has no obsolete inlinedAt field (Record[9]).
1907   //   In this case Record size will be 8, HasAlignment flag is false.
1908   // 2) Record has artificial tag (Record[1]),
1909   //   has no obsolete inlignedAt field (Record[9]).
1910   //   In this case Record size will be 9, HasAlignment flag is false.
1911   // 3) Record has both artificial tag (Record[1]) and
1912   //   obsolete inlignedAt field (Record[9]).
1913   //   In this case Record size will be 10, HasAlignment flag is false.
1914   // 4) Record has neither artificial tag, nor inlignedAt field, but
1915   //   HasAlignment flag is true and Record[8] contains alignment value.
1916   const uint64_t HasAlignmentFlag = 1 << 1;
1917   Record.push_back((uint64_t)N->isDistinct() | HasAlignmentFlag);
1918   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1919   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1920   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1921   Record.push_back(N->getLine());
1922   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1923   Record.push_back(N->getArg());
1924   Record.push_back(N->getFlags());
1925   Record.push_back(N->getAlignInBits());
1926 
1927   Stream.EmitRecord(bitc::METADATA_LOCAL_VAR, Record, Abbrev);
1928   Record.clear();
1929 }
1930 
1931 void ModuleBitcodeWriter::writeDILabel(
1932     const DILabel *N, SmallVectorImpl<uint64_t> &Record,
1933     unsigned Abbrev) {
1934   Record.push_back((uint64_t)N->isDistinct());
1935   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1936   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1937   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1938   Record.push_back(N->getLine());
1939 
1940   Stream.EmitRecord(bitc::METADATA_LABEL, Record, Abbrev);
1941   Record.clear();
1942 }
1943 
1944 void ModuleBitcodeWriter::writeDIExpression(const DIExpression *N,
1945                                             SmallVectorImpl<uint64_t> &Record,
1946                                             unsigned Abbrev) {
1947   Record.reserve(N->getElements().size() + 1);
1948   const uint64_t Version = 3 << 1;
1949   Record.push_back((uint64_t)N->isDistinct() | Version);
1950   Record.append(N->elements_begin(), N->elements_end());
1951 
1952   Stream.EmitRecord(bitc::METADATA_EXPRESSION, Record, Abbrev);
1953   Record.clear();
1954 }
1955 
1956 void ModuleBitcodeWriter::writeDIGlobalVariableExpression(
1957     const DIGlobalVariableExpression *N, SmallVectorImpl<uint64_t> &Record,
1958     unsigned Abbrev) {
1959   Record.push_back(N->isDistinct());
1960   Record.push_back(VE.getMetadataOrNullID(N->getVariable()));
1961   Record.push_back(VE.getMetadataOrNullID(N->getExpression()));
1962 
1963   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR_EXPR, Record, Abbrev);
1964   Record.clear();
1965 }
1966 
1967 void ModuleBitcodeWriter::writeDIObjCProperty(const DIObjCProperty *N,
1968                                               SmallVectorImpl<uint64_t> &Record,
1969                                               unsigned Abbrev) {
1970   Record.push_back(N->isDistinct());
1971   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1972   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1973   Record.push_back(N->getLine());
1974   Record.push_back(VE.getMetadataOrNullID(N->getRawSetterName()));
1975   Record.push_back(VE.getMetadataOrNullID(N->getRawGetterName()));
1976   Record.push_back(N->getAttributes());
1977   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1978 
1979   Stream.EmitRecord(bitc::METADATA_OBJC_PROPERTY, Record, Abbrev);
1980   Record.clear();
1981 }
1982 
1983 void ModuleBitcodeWriter::writeDIImportedEntity(
1984     const DIImportedEntity *N, SmallVectorImpl<uint64_t> &Record,
1985     unsigned Abbrev) {
1986   Record.push_back(N->isDistinct());
1987   Record.push_back(N->getTag());
1988   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1989   Record.push_back(VE.getMetadataOrNullID(N->getEntity()));
1990   Record.push_back(N->getLine());
1991   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1992   Record.push_back(VE.getMetadataOrNullID(N->getRawFile()));
1993 
1994   Stream.EmitRecord(bitc::METADATA_IMPORTED_ENTITY, Record, Abbrev);
1995   Record.clear();
1996 }
1997 
1998 unsigned ModuleBitcodeWriter::createNamedMetadataAbbrev() {
1999   auto Abbv = std::make_shared<BitCodeAbbrev>();
2000   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
2001   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2002   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2003   return Stream.EmitAbbrev(std::move(Abbv));
2004 }
2005 
2006 void ModuleBitcodeWriter::writeNamedMetadata(
2007     SmallVectorImpl<uint64_t> &Record) {
2008   if (M.named_metadata_empty())
2009     return;
2010 
2011   unsigned Abbrev = createNamedMetadataAbbrev();
2012   for (const NamedMDNode &NMD : M.named_metadata()) {
2013     // Write name.
2014     StringRef Str = NMD.getName();
2015     Record.append(Str.bytes_begin(), Str.bytes_end());
2016     Stream.EmitRecord(bitc::METADATA_NAME, Record, Abbrev);
2017     Record.clear();
2018 
2019     // Write named metadata operands.
2020     for (const MDNode *N : NMD.operands())
2021       Record.push_back(VE.getMetadataID(N));
2022     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
2023     Record.clear();
2024   }
2025 }
2026 
2027 unsigned ModuleBitcodeWriter::createMetadataStringsAbbrev() {
2028   auto Abbv = std::make_shared<BitCodeAbbrev>();
2029   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRINGS));
2030   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // # of strings
2031   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // offset to chars
2032   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
2033   return Stream.EmitAbbrev(std::move(Abbv));
2034 }
2035 
2036 /// Write out a record for MDString.
2037 ///
2038 /// All the metadata strings in a metadata block are emitted in a single
2039 /// record.  The sizes and strings themselves are shoved into a blob.
2040 void ModuleBitcodeWriter::writeMetadataStrings(
2041     ArrayRef<const Metadata *> Strings, SmallVectorImpl<uint64_t> &Record) {
2042   if (Strings.empty())
2043     return;
2044 
2045   // Start the record with the number of strings.
2046   Record.push_back(bitc::METADATA_STRINGS);
2047   Record.push_back(Strings.size());
2048 
2049   // Emit the sizes of the strings in the blob.
2050   SmallString<256> Blob;
2051   {
2052     BitstreamWriter W(Blob);
2053     for (const Metadata *MD : Strings)
2054       W.EmitVBR(cast<MDString>(MD)->getLength(), 6);
2055     W.FlushToWord();
2056   }
2057 
2058   // Add the offset to the strings to the record.
2059   Record.push_back(Blob.size());
2060 
2061   // Add the strings to the blob.
2062   for (const Metadata *MD : Strings)
2063     Blob.append(cast<MDString>(MD)->getString());
2064 
2065   // Emit the final record.
2066   Stream.EmitRecordWithBlob(createMetadataStringsAbbrev(), Record, Blob);
2067   Record.clear();
2068 }
2069 
2070 // Generates an enum to use as an index in the Abbrev array of Metadata record.
2071 enum MetadataAbbrev : unsigned {
2072 #define HANDLE_MDNODE_LEAF(CLASS) CLASS##AbbrevID,
2073 #include "llvm/IR/Metadata.def"
2074   LastPlusOne
2075 };
2076 
2077 void ModuleBitcodeWriter::writeMetadataRecords(
2078     ArrayRef<const Metadata *> MDs, SmallVectorImpl<uint64_t> &Record,
2079     std::vector<unsigned> *MDAbbrevs, std::vector<uint64_t> *IndexPos) {
2080   if (MDs.empty())
2081     return;
2082 
2083   // Initialize MDNode abbreviations.
2084 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
2085 #include "llvm/IR/Metadata.def"
2086 
2087   for (const Metadata *MD : MDs) {
2088     if (IndexPos)
2089       IndexPos->push_back(Stream.GetCurrentBitNo());
2090     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
2091       assert(N->isResolved() && "Expected forward references to be resolved");
2092 
2093       switch (N->getMetadataID()) {
2094       default:
2095         llvm_unreachable("Invalid MDNode subclass");
2096 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
2097   case Metadata::CLASS##Kind:                                                  \
2098     if (MDAbbrevs)                                                             \
2099       write##CLASS(cast<CLASS>(N), Record,                                     \
2100                    (*MDAbbrevs)[MetadataAbbrev::CLASS##AbbrevID]);             \
2101     else                                                                       \
2102       write##CLASS(cast<CLASS>(N), Record, CLASS##Abbrev);                     \
2103     continue;
2104 #include "llvm/IR/Metadata.def"
2105       }
2106     }
2107     writeValueAsMetadata(cast<ValueAsMetadata>(MD), Record);
2108   }
2109 }
2110 
2111 void ModuleBitcodeWriter::writeModuleMetadata() {
2112   if (!VE.hasMDs() && M.named_metadata_empty())
2113     return;
2114 
2115   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 4);
2116   SmallVector<uint64_t, 64> Record;
2117 
2118   // Emit all abbrevs upfront, so that the reader can jump in the middle of the
2119   // block and load any metadata.
2120   std::vector<unsigned> MDAbbrevs;
2121 
2122   MDAbbrevs.resize(MetadataAbbrev::LastPlusOne);
2123   MDAbbrevs[MetadataAbbrev::DILocationAbbrevID] = createDILocationAbbrev();
2124   MDAbbrevs[MetadataAbbrev::GenericDINodeAbbrevID] =
2125       createGenericDINodeAbbrev();
2126 
2127   auto Abbv = std::make_shared<BitCodeAbbrev>();
2128   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX_OFFSET));
2129   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2130   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2131   unsigned OffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2132 
2133   Abbv = std::make_shared<BitCodeAbbrev>();
2134   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX));
2135   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2136   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2137   unsigned IndexAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2138 
2139   // Emit MDStrings together upfront.
2140   writeMetadataStrings(VE.getMDStrings(), Record);
2141 
2142   // We only emit an index for the metadata record if we have more than a given
2143   // (naive) threshold of metadatas, otherwise it is not worth it.
2144   if (VE.getNonMDStrings().size() > IndexThreshold) {
2145     // Write a placeholder value in for the offset of the metadata index,
2146     // which is written after the records, so that it can include
2147     // the offset of each entry. The placeholder offset will be
2148     // updated after all records are emitted.
2149     uint64_t Vals[] = {0, 0};
2150     Stream.EmitRecord(bitc::METADATA_INDEX_OFFSET, Vals, OffsetAbbrev);
2151   }
2152 
2153   // Compute and save the bit offset to the current position, which will be
2154   // patched when we emit the index later. We can simply subtract the 64-bit
2155   // fixed size from the current bit number to get the location to backpatch.
2156   uint64_t IndexOffsetRecordBitPos = Stream.GetCurrentBitNo();
2157 
2158   // This index will contain the bitpos for each individual record.
2159   std::vector<uint64_t> IndexPos;
2160   IndexPos.reserve(VE.getNonMDStrings().size());
2161 
2162   // Write all the records
2163   writeMetadataRecords(VE.getNonMDStrings(), Record, &MDAbbrevs, &IndexPos);
2164 
2165   if (VE.getNonMDStrings().size() > IndexThreshold) {
2166     // Now that we have emitted all the records we will emit the index. But
2167     // first
2168     // backpatch the forward reference so that the reader can skip the records
2169     // efficiently.
2170     Stream.BackpatchWord64(IndexOffsetRecordBitPos - 64,
2171                            Stream.GetCurrentBitNo() - IndexOffsetRecordBitPos);
2172 
2173     // Delta encode the index.
2174     uint64_t PreviousValue = IndexOffsetRecordBitPos;
2175     for (auto &Elt : IndexPos) {
2176       auto EltDelta = Elt - PreviousValue;
2177       PreviousValue = Elt;
2178       Elt = EltDelta;
2179     }
2180     // Emit the index record.
2181     Stream.EmitRecord(bitc::METADATA_INDEX, IndexPos, IndexAbbrev);
2182     IndexPos.clear();
2183   }
2184 
2185   // Write the named metadata now.
2186   writeNamedMetadata(Record);
2187 
2188   auto AddDeclAttachedMetadata = [&](const GlobalObject &GO) {
2189     SmallVector<uint64_t, 4> Record;
2190     Record.push_back(VE.getValueID(&GO));
2191     pushGlobalMetadataAttachment(Record, GO);
2192     Stream.EmitRecord(bitc::METADATA_GLOBAL_DECL_ATTACHMENT, Record);
2193   };
2194   for (const Function &F : M)
2195     if (F.isDeclaration() && F.hasMetadata())
2196       AddDeclAttachedMetadata(F);
2197   // FIXME: Only store metadata for declarations here, and move data for global
2198   // variable definitions to a separate block (PR28134).
2199   for (const GlobalVariable &GV : M.globals())
2200     if (GV.hasMetadata())
2201       AddDeclAttachedMetadata(GV);
2202 
2203   Stream.ExitBlock();
2204 }
2205 
2206 void ModuleBitcodeWriter::writeFunctionMetadata(const Function &F) {
2207   if (!VE.hasMDs())
2208     return;
2209 
2210   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
2211   SmallVector<uint64_t, 64> Record;
2212   writeMetadataStrings(VE.getMDStrings(), Record);
2213   writeMetadataRecords(VE.getNonMDStrings(), Record);
2214   Stream.ExitBlock();
2215 }
2216 
2217 void ModuleBitcodeWriter::pushGlobalMetadataAttachment(
2218     SmallVectorImpl<uint64_t> &Record, const GlobalObject &GO) {
2219   // [n x [id, mdnode]]
2220   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2221   GO.getAllMetadata(MDs);
2222   for (const auto &I : MDs) {
2223     Record.push_back(I.first);
2224     Record.push_back(VE.getMetadataID(I.second));
2225   }
2226 }
2227 
2228 void ModuleBitcodeWriter::writeFunctionMetadataAttachment(const Function &F) {
2229   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
2230 
2231   SmallVector<uint64_t, 64> Record;
2232 
2233   if (F.hasMetadata()) {
2234     pushGlobalMetadataAttachment(Record, F);
2235     Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2236     Record.clear();
2237   }
2238 
2239   // Write metadata attachments
2240   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
2241   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2242   for (const BasicBlock &BB : F)
2243     for (const Instruction &I : BB) {
2244       MDs.clear();
2245       I.getAllMetadataOtherThanDebugLoc(MDs);
2246 
2247       // If no metadata, ignore instruction.
2248       if (MDs.empty()) continue;
2249 
2250       Record.push_back(VE.getInstructionID(&I));
2251 
2252       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
2253         Record.push_back(MDs[i].first);
2254         Record.push_back(VE.getMetadataID(MDs[i].second));
2255       }
2256       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2257       Record.clear();
2258     }
2259 
2260   Stream.ExitBlock();
2261 }
2262 
2263 void ModuleBitcodeWriter::writeModuleMetadataKinds() {
2264   SmallVector<uint64_t, 64> Record;
2265 
2266   // Write metadata kinds
2267   // METADATA_KIND - [n x [id, name]]
2268   SmallVector<StringRef, 8> Names;
2269   M.getMDKindNames(Names);
2270 
2271   if (Names.empty()) return;
2272 
2273   Stream.EnterSubblock(bitc::METADATA_KIND_BLOCK_ID, 3);
2274 
2275   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
2276     Record.push_back(MDKindID);
2277     StringRef KName = Names[MDKindID];
2278     Record.append(KName.begin(), KName.end());
2279 
2280     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
2281     Record.clear();
2282   }
2283 
2284   Stream.ExitBlock();
2285 }
2286 
2287 void ModuleBitcodeWriter::writeOperandBundleTags() {
2288   // Write metadata kinds
2289   //
2290   // OPERAND_BUNDLE_TAGS_BLOCK_ID : N x OPERAND_BUNDLE_TAG
2291   //
2292   // OPERAND_BUNDLE_TAG - [strchr x N]
2293 
2294   SmallVector<StringRef, 8> Tags;
2295   M.getOperandBundleTags(Tags);
2296 
2297   if (Tags.empty())
2298     return;
2299 
2300   Stream.EnterSubblock(bitc::OPERAND_BUNDLE_TAGS_BLOCK_ID, 3);
2301 
2302   SmallVector<uint64_t, 64> Record;
2303 
2304   for (auto Tag : Tags) {
2305     Record.append(Tag.begin(), Tag.end());
2306 
2307     Stream.EmitRecord(bitc::OPERAND_BUNDLE_TAG, Record, 0);
2308     Record.clear();
2309   }
2310 
2311   Stream.ExitBlock();
2312 }
2313 
2314 void ModuleBitcodeWriter::writeSyncScopeNames() {
2315   SmallVector<StringRef, 8> SSNs;
2316   M.getContext().getSyncScopeNames(SSNs);
2317   if (SSNs.empty())
2318     return;
2319 
2320   Stream.EnterSubblock(bitc::SYNC_SCOPE_NAMES_BLOCK_ID, 2);
2321 
2322   SmallVector<uint64_t, 64> Record;
2323   for (auto SSN : SSNs) {
2324     Record.append(SSN.begin(), SSN.end());
2325     Stream.EmitRecord(bitc::SYNC_SCOPE_NAME, Record, 0);
2326     Record.clear();
2327   }
2328 
2329   Stream.ExitBlock();
2330 }
2331 
2332 void ModuleBitcodeWriter::writeConstants(unsigned FirstVal, unsigned LastVal,
2333                                          bool isGlobal) {
2334   if (FirstVal == LastVal) return;
2335 
2336   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
2337 
2338   unsigned AggregateAbbrev = 0;
2339   unsigned String8Abbrev = 0;
2340   unsigned CString7Abbrev = 0;
2341   unsigned CString6Abbrev = 0;
2342   // If this is a constant pool for the module, emit module-specific abbrevs.
2343   if (isGlobal) {
2344     // Abbrev for CST_CODE_AGGREGATE.
2345     auto Abbv = std::make_shared<BitCodeAbbrev>();
2346     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
2347     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2348     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
2349     AggregateAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2350 
2351     // Abbrev for CST_CODE_STRING.
2352     Abbv = std::make_shared<BitCodeAbbrev>();
2353     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
2354     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2355     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2356     String8Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2357     // Abbrev for CST_CODE_CSTRING.
2358     Abbv = std::make_shared<BitCodeAbbrev>();
2359     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2360     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2361     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2362     CString7Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2363     // Abbrev for CST_CODE_CSTRING.
2364     Abbv = std::make_shared<BitCodeAbbrev>();
2365     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2366     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2367     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2368     CString6Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2369   }
2370 
2371   SmallVector<uint64_t, 64> Record;
2372 
2373   const ValueEnumerator::ValueList &Vals = VE.getValues();
2374   Type *LastTy = nullptr;
2375   for (unsigned i = FirstVal; i != LastVal; ++i) {
2376     const Value *V = Vals[i].first;
2377     // If we need to switch types, do so now.
2378     if (V->getType() != LastTy) {
2379       LastTy = V->getType();
2380       Record.push_back(VE.getTypeID(LastTy));
2381       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
2382                         CONSTANTS_SETTYPE_ABBREV);
2383       Record.clear();
2384     }
2385 
2386     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
2387       Record.push_back(unsigned(IA->hasSideEffects()) |
2388                        unsigned(IA->isAlignStack()) << 1 |
2389                        unsigned(IA->getDialect()&1) << 2);
2390 
2391       // Add the asm string.
2392       const std::string &AsmStr = IA->getAsmString();
2393       Record.push_back(AsmStr.size());
2394       Record.append(AsmStr.begin(), AsmStr.end());
2395 
2396       // Add the constraint string.
2397       const std::string &ConstraintStr = IA->getConstraintString();
2398       Record.push_back(ConstraintStr.size());
2399       Record.append(ConstraintStr.begin(), ConstraintStr.end());
2400       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
2401       Record.clear();
2402       continue;
2403     }
2404     const Constant *C = cast<Constant>(V);
2405     unsigned Code = -1U;
2406     unsigned AbbrevToUse = 0;
2407     if (C->isNullValue()) {
2408       Code = bitc::CST_CODE_NULL;
2409     } else if (isa<UndefValue>(C)) {
2410       Code = bitc::CST_CODE_UNDEF;
2411     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
2412       if (IV->getBitWidth() <= 64) {
2413         uint64_t V = IV->getSExtValue();
2414         emitSignedInt64(Record, V);
2415         Code = bitc::CST_CODE_INTEGER;
2416         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
2417       } else {                             // Wide integers, > 64 bits in size.
2418         emitWideAPInt(Record, IV->getValue());
2419         Code = bitc::CST_CODE_WIDE_INTEGER;
2420       }
2421     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
2422       Code = bitc::CST_CODE_FLOAT;
2423       Type *Ty = CFP->getType();
2424       if (Ty->isHalfTy() || Ty->isBFloatTy() || Ty->isFloatTy() ||
2425           Ty->isDoubleTy()) {
2426         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
2427       } else if (Ty->isX86_FP80Ty()) {
2428         // api needed to prevent premature destruction
2429         // bits are not in the same order as a normal i80 APInt, compensate.
2430         APInt api = CFP->getValueAPF().bitcastToAPInt();
2431         const uint64_t *p = api.getRawData();
2432         Record.push_back((p[1] << 48) | (p[0] >> 16));
2433         Record.push_back(p[0] & 0xffffLL);
2434       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
2435         APInt api = CFP->getValueAPF().bitcastToAPInt();
2436         const uint64_t *p = api.getRawData();
2437         Record.push_back(p[0]);
2438         Record.push_back(p[1]);
2439       } else {
2440         assert(0 && "Unknown FP type!");
2441       }
2442     } else if (isa<ConstantDataSequential>(C) &&
2443                cast<ConstantDataSequential>(C)->isString()) {
2444       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
2445       // Emit constant strings specially.
2446       unsigned NumElts = Str->getNumElements();
2447       // If this is a null-terminated string, use the denser CSTRING encoding.
2448       if (Str->isCString()) {
2449         Code = bitc::CST_CODE_CSTRING;
2450         --NumElts;  // Don't encode the null, which isn't allowed by char6.
2451       } else {
2452         Code = bitc::CST_CODE_STRING;
2453         AbbrevToUse = String8Abbrev;
2454       }
2455       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
2456       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
2457       for (unsigned i = 0; i != NumElts; ++i) {
2458         unsigned char V = Str->getElementAsInteger(i);
2459         Record.push_back(V);
2460         isCStr7 &= (V & 128) == 0;
2461         if (isCStrChar6)
2462           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
2463       }
2464 
2465       if (isCStrChar6)
2466         AbbrevToUse = CString6Abbrev;
2467       else if (isCStr7)
2468         AbbrevToUse = CString7Abbrev;
2469     } else if (const ConstantDataSequential *CDS =
2470                   dyn_cast<ConstantDataSequential>(C)) {
2471       Code = bitc::CST_CODE_DATA;
2472       Type *EltTy = CDS->getElementType();
2473       if (isa<IntegerType>(EltTy)) {
2474         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2475           Record.push_back(CDS->getElementAsInteger(i));
2476       } else {
2477         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2478           Record.push_back(
2479               CDS->getElementAsAPFloat(i).bitcastToAPInt().getLimitedValue());
2480       }
2481     } else if (isa<ConstantAggregate>(C)) {
2482       Code = bitc::CST_CODE_AGGREGATE;
2483       for (const Value *Op : C->operands())
2484         Record.push_back(VE.getValueID(Op));
2485       AbbrevToUse = AggregateAbbrev;
2486     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
2487       switch (CE->getOpcode()) {
2488       default:
2489         if (Instruction::isCast(CE->getOpcode())) {
2490           Code = bitc::CST_CODE_CE_CAST;
2491           Record.push_back(getEncodedCastOpcode(CE->getOpcode()));
2492           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2493           Record.push_back(VE.getValueID(C->getOperand(0)));
2494           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
2495         } else {
2496           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
2497           Code = bitc::CST_CODE_CE_BINOP;
2498           Record.push_back(getEncodedBinaryOpcode(CE->getOpcode()));
2499           Record.push_back(VE.getValueID(C->getOperand(0)));
2500           Record.push_back(VE.getValueID(C->getOperand(1)));
2501           uint64_t Flags = getOptimizationFlags(CE);
2502           if (Flags != 0)
2503             Record.push_back(Flags);
2504         }
2505         break;
2506       case Instruction::FNeg: {
2507         assert(CE->getNumOperands() == 1 && "Unknown constant expr!");
2508         Code = bitc::CST_CODE_CE_UNOP;
2509         Record.push_back(getEncodedUnaryOpcode(CE->getOpcode()));
2510         Record.push_back(VE.getValueID(C->getOperand(0)));
2511         uint64_t Flags = getOptimizationFlags(CE);
2512         if (Flags != 0)
2513           Record.push_back(Flags);
2514         break;
2515       }
2516       case Instruction::GetElementPtr: {
2517         Code = bitc::CST_CODE_CE_GEP;
2518         const auto *GO = cast<GEPOperator>(C);
2519         Record.push_back(VE.getTypeID(GO->getSourceElementType()));
2520         if (Optional<unsigned> Idx = GO->getInRangeIndex()) {
2521           Code = bitc::CST_CODE_CE_GEP_WITH_INRANGE_INDEX;
2522           Record.push_back((*Idx << 1) | GO->isInBounds());
2523         } else if (GO->isInBounds())
2524           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
2525         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
2526           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
2527           Record.push_back(VE.getValueID(C->getOperand(i)));
2528         }
2529         break;
2530       }
2531       case Instruction::Select:
2532         Code = bitc::CST_CODE_CE_SELECT;
2533         Record.push_back(VE.getValueID(C->getOperand(0)));
2534         Record.push_back(VE.getValueID(C->getOperand(1)));
2535         Record.push_back(VE.getValueID(C->getOperand(2)));
2536         break;
2537       case Instruction::ExtractElement:
2538         Code = bitc::CST_CODE_CE_EXTRACTELT;
2539         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2540         Record.push_back(VE.getValueID(C->getOperand(0)));
2541         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
2542         Record.push_back(VE.getValueID(C->getOperand(1)));
2543         break;
2544       case Instruction::InsertElement:
2545         Code = bitc::CST_CODE_CE_INSERTELT;
2546         Record.push_back(VE.getValueID(C->getOperand(0)));
2547         Record.push_back(VE.getValueID(C->getOperand(1)));
2548         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
2549         Record.push_back(VE.getValueID(C->getOperand(2)));
2550         break;
2551       case Instruction::ShuffleVector:
2552         // If the return type and argument types are the same, this is a
2553         // standard shufflevector instruction.  If the types are different,
2554         // then the shuffle is widening or truncating the input vectors, and
2555         // the argument type must also be encoded.
2556         if (C->getType() == C->getOperand(0)->getType()) {
2557           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
2558         } else {
2559           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
2560           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2561         }
2562         Record.push_back(VE.getValueID(C->getOperand(0)));
2563         Record.push_back(VE.getValueID(C->getOperand(1)));
2564         Record.push_back(VE.getValueID(CE->getShuffleMaskForBitcode()));
2565         break;
2566       case Instruction::ICmp:
2567       case Instruction::FCmp:
2568         Code = bitc::CST_CODE_CE_CMP;
2569         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2570         Record.push_back(VE.getValueID(C->getOperand(0)));
2571         Record.push_back(VE.getValueID(C->getOperand(1)));
2572         Record.push_back(CE->getPredicate());
2573         break;
2574       }
2575     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
2576       Code = bitc::CST_CODE_BLOCKADDRESS;
2577       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
2578       Record.push_back(VE.getValueID(BA->getFunction()));
2579       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
2580     } else {
2581 #ifndef NDEBUG
2582       C->dump();
2583 #endif
2584       llvm_unreachable("Unknown constant!");
2585     }
2586     Stream.EmitRecord(Code, Record, AbbrevToUse);
2587     Record.clear();
2588   }
2589 
2590   Stream.ExitBlock();
2591 }
2592 
2593 void ModuleBitcodeWriter::writeModuleConstants() {
2594   const ValueEnumerator::ValueList &Vals = VE.getValues();
2595 
2596   // Find the first constant to emit, which is the first non-globalvalue value.
2597   // We know globalvalues have been emitted by WriteModuleInfo.
2598   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
2599     if (!isa<GlobalValue>(Vals[i].first)) {
2600       writeConstants(i, Vals.size(), true);
2601       return;
2602     }
2603   }
2604 }
2605 
2606 /// pushValueAndType - The file has to encode both the value and type id for
2607 /// many values, because we need to know what type to create for forward
2608 /// references.  However, most operands are not forward references, so this type
2609 /// field is not needed.
2610 ///
2611 /// This function adds V's value ID to Vals.  If the value ID is higher than the
2612 /// instruction ID, then it is a forward reference, and it also includes the
2613 /// type ID.  The value ID that is written is encoded relative to the InstID.
2614 bool ModuleBitcodeWriter::pushValueAndType(const Value *V, unsigned InstID,
2615                                            SmallVectorImpl<unsigned> &Vals) {
2616   unsigned ValID = VE.getValueID(V);
2617   // Make encoding relative to the InstID.
2618   Vals.push_back(InstID - ValID);
2619   if (ValID >= InstID) {
2620     Vals.push_back(VE.getTypeID(V->getType()));
2621     return true;
2622   }
2623   return false;
2624 }
2625 
2626 void ModuleBitcodeWriter::writeOperandBundles(const CallBase &CS,
2627                                               unsigned InstID) {
2628   SmallVector<unsigned, 64> Record;
2629   LLVMContext &C = CS.getContext();
2630 
2631   for (unsigned i = 0, e = CS.getNumOperandBundles(); i != e; ++i) {
2632     const auto &Bundle = CS.getOperandBundleAt(i);
2633     Record.push_back(C.getOperandBundleTagID(Bundle.getTagName()));
2634 
2635     for (auto &Input : Bundle.Inputs)
2636       pushValueAndType(Input, InstID, Record);
2637 
2638     Stream.EmitRecord(bitc::FUNC_CODE_OPERAND_BUNDLE, Record);
2639     Record.clear();
2640   }
2641 }
2642 
2643 /// pushValue - Like pushValueAndType, but where the type of the value is
2644 /// omitted (perhaps it was already encoded in an earlier operand).
2645 void ModuleBitcodeWriter::pushValue(const Value *V, unsigned InstID,
2646                                     SmallVectorImpl<unsigned> &Vals) {
2647   unsigned ValID = VE.getValueID(V);
2648   Vals.push_back(InstID - ValID);
2649 }
2650 
2651 void ModuleBitcodeWriter::pushValueSigned(const Value *V, unsigned InstID,
2652                                           SmallVectorImpl<uint64_t> &Vals) {
2653   unsigned ValID = VE.getValueID(V);
2654   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
2655   emitSignedInt64(Vals, diff);
2656 }
2657 
2658 /// WriteInstruction - Emit an instruction to the specified stream.
2659 void ModuleBitcodeWriter::writeInstruction(const Instruction &I,
2660                                            unsigned InstID,
2661                                            SmallVectorImpl<unsigned> &Vals) {
2662   unsigned Code = 0;
2663   unsigned AbbrevToUse = 0;
2664   VE.setInstructionID(&I);
2665   switch (I.getOpcode()) {
2666   default:
2667     if (Instruction::isCast(I.getOpcode())) {
2668       Code = bitc::FUNC_CODE_INST_CAST;
2669       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2670         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
2671       Vals.push_back(VE.getTypeID(I.getType()));
2672       Vals.push_back(getEncodedCastOpcode(I.getOpcode()));
2673     } else {
2674       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
2675       Code = bitc::FUNC_CODE_INST_BINOP;
2676       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2677         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
2678       pushValue(I.getOperand(1), InstID, Vals);
2679       Vals.push_back(getEncodedBinaryOpcode(I.getOpcode()));
2680       uint64_t Flags = getOptimizationFlags(&I);
2681       if (Flags != 0) {
2682         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
2683           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
2684         Vals.push_back(Flags);
2685       }
2686     }
2687     break;
2688   case Instruction::FNeg: {
2689     Code = bitc::FUNC_CODE_INST_UNOP;
2690     if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2691       AbbrevToUse = FUNCTION_INST_UNOP_ABBREV;
2692     Vals.push_back(getEncodedUnaryOpcode(I.getOpcode()));
2693     uint64_t Flags = getOptimizationFlags(&I);
2694     if (Flags != 0) {
2695       if (AbbrevToUse == FUNCTION_INST_UNOP_ABBREV)
2696         AbbrevToUse = FUNCTION_INST_UNOP_FLAGS_ABBREV;
2697       Vals.push_back(Flags);
2698     }
2699     break;
2700   }
2701   case Instruction::GetElementPtr: {
2702     Code = bitc::FUNC_CODE_INST_GEP;
2703     AbbrevToUse = FUNCTION_INST_GEP_ABBREV;
2704     auto &GEPInst = cast<GetElementPtrInst>(I);
2705     Vals.push_back(GEPInst.isInBounds());
2706     Vals.push_back(VE.getTypeID(GEPInst.getSourceElementType()));
2707     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
2708       pushValueAndType(I.getOperand(i), InstID, Vals);
2709     break;
2710   }
2711   case Instruction::ExtractValue: {
2712     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
2713     pushValueAndType(I.getOperand(0), InstID, Vals);
2714     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
2715     Vals.append(EVI->idx_begin(), EVI->idx_end());
2716     break;
2717   }
2718   case Instruction::InsertValue: {
2719     Code = bitc::FUNC_CODE_INST_INSERTVAL;
2720     pushValueAndType(I.getOperand(0), InstID, Vals);
2721     pushValueAndType(I.getOperand(1), InstID, Vals);
2722     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
2723     Vals.append(IVI->idx_begin(), IVI->idx_end());
2724     break;
2725   }
2726   case Instruction::Select: {
2727     Code = bitc::FUNC_CODE_INST_VSELECT;
2728     pushValueAndType(I.getOperand(1), InstID, Vals);
2729     pushValue(I.getOperand(2), InstID, Vals);
2730     pushValueAndType(I.getOperand(0), InstID, Vals);
2731     uint64_t Flags = getOptimizationFlags(&I);
2732     if (Flags != 0)
2733       Vals.push_back(Flags);
2734     break;
2735   }
2736   case Instruction::ExtractElement:
2737     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
2738     pushValueAndType(I.getOperand(0), InstID, Vals);
2739     pushValueAndType(I.getOperand(1), InstID, Vals);
2740     break;
2741   case Instruction::InsertElement:
2742     Code = bitc::FUNC_CODE_INST_INSERTELT;
2743     pushValueAndType(I.getOperand(0), InstID, Vals);
2744     pushValue(I.getOperand(1), InstID, Vals);
2745     pushValueAndType(I.getOperand(2), InstID, Vals);
2746     break;
2747   case Instruction::ShuffleVector:
2748     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
2749     pushValueAndType(I.getOperand(0), InstID, Vals);
2750     pushValue(I.getOperand(1), InstID, Vals);
2751     pushValue(cast<ShuffleVectorInst>(I).getShuffleMaskForBitcode(), InstID,
2752               Vals);
2753     break;
2754   case Instruction::ICmp:
2755   case Instruction::FCmp: {
2756     // compare returning Int1Ty or vector of Int1Ty
2757     Code = bitc::FUNC_CODE_INST_CMP2;
2758     pushValueAndType(I.getOperand(0), InstID, Vals);
2759     pushValue(I.getOperand(1), InstID, Vals);
2760     Vals.push_back(cast<CmpInst>(I).getPredicate());
2761     uint64_t Flags = getOptimizationFlags(&I);
2762     if (Flags != 0)
2763       Vals.push_back(Flags);
2764     break;
2765   }
2766 
2767   case Instruction::Ret:
2768     {
2769       Code = bitc::FUNC_CODE_INST_RET;
2770       unsigned NumOperands = I.getNumOperands();
2771       if (NumOperands == 0)
2772         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
2773       else if (NumOperands == 1) {
2774         if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2775           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
2776       } else {
2777         for (unsigned i = 0, e = NumOperands; i != e; ++i)
2778           pushValueAndType(I.getOperand(i), InstID, Vals);
2779       }
2780     }
2781     break;
2782   case Instruction::Br:
2783     {
2784       Code = bitc::FUNC_CODE_INST_BR;
2785       const BranchInst &II = cast<BranchInst>(I);
2786       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
2787       if (II.isConditional()) {
2788         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
2789         pushValue(II.getCondition(), InstID, Vals);
2790       }
2791     }
2792     break;
2793   case Instruction::Switch:
2794     {
2795       Code = bitc::FUNC_CODE_INST_SWITCH;
2796       const SwitchInst &SI = cast<SwitchInst>(I);
2797       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
2798       pushValue(SI.getCondition(), InstID, Vals);
2799       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
2800       for (auto Case : SI.cases()) {
2801         Vals.push_back(VE.getValueID(Case.getCaseValue()));
2802         Vals.push_back(VE.getValueID(Case.getCaseSuccessor()));
2803       }
2804     }
2805     break;
2806   case Instruction::IndirectBr:
2807     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
2808     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2809     // Encode the address operand as relative, but not the basic blocks.
2810     pushValue(I.getOperand(0), InstID, Vals);
2811     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
2812       Vals.push_back(VE.getValueID(I.getOperand(i)));
2813     break;
2814 
2815   case Instruction::Invoke: {
2816     const InvokeInst *II = cast<InvokeInst>(&I);
2817     const Value *Callee = II->getCalledOperand();
2818     FunctionType *FTy = II->getFunctionType();
2819 
2820     if (II->hasOperandBundles())
2821       writeOperandBundles(*II, InstID);
2822 
2823     Code = bitc::FUNC_CODE_INST_INVOKE;
2824 
2825     Vals.push_back(VE.getAttributeListID(II->getAttributes()));
2826     Vals.push_back(II->getCallingConv() | 1 << 13);
2827     Vals.push_back(VE.getValueID(II->getNormalDest()));
2828     Vals.push_back(VE.getValueID(II->getUnwindDest()));
2829     Vals.push_back(VE.getTypeID(FTy));
2830     pushValueAndType(Callee, InstID, Vals);
2831 
2832     // Emit value #'s for the fixed parameters.
2833     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
2834       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
2835 
2836     // Emit type/value pairs for varargs params.
2837     if (FTy->isVarArg()) {
2838       for (unsigned i = FTy->getNumParams(), e = II->getNumArgOperands();
2839            i != e; ++i)
2840         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
2841     }
2842     break;
2843   }
2844   case Instruction::Resume:
2845     Code = bitc::FUNC_CODE_INST_RESUME;
2846     pushValueAndType(I.getOperand(0), InstID, Vals);
2847     break;
2848   case Instruction::CleanupRet: {
2849     Code = bitc::FUNC_CODE_INST_CLEANUPRET;
2850     const auto &CRI = cast<CleanupReturnInst>(I);
2851     pushValue(CRI.getCleanupPad(), InstID, Vals);
2852     if (CRI.hasUnwindDest())
2853       Vals.push_back(VE.getValueID(CRI.getUnwindDest()));
2854     break;
2855   }
2856   case Instruction::CatchRet: {
2857     Code = bitc::FUNC_CODE_INST_CATCHRET;
2858     const auto &CRI = cast<CatchReturnInst>(I);
2859     pushValue(CRI.getCatchPad(), InstID, Vals);
2860     Vals.push_back(VE.getValueID(CRI.getSuccessor()));
2861     break;
2862   }
2863   case Instruction::CleanupPad:
2864   case Instruction::CatchPad: {
2865     const auto &FuncletPad = cast<FuncletPadInst>(I);
2866     Code = isa<CatchPadInst>(FuncletPad) ? bitc::FUNC_CODE_INST_CATCHPAD
2867                                          : bitc::FUNC_CODE_INST_CLEANUPPAD;
2868     pushValue(FuncletPad.getParentPad(), InstID, Vals);
2869 
2870     unsigned NumArgOperands = FuncletPad.getNumArgOperands();
2871     Vals.push_back(NumArgOperands);
2872     for (unsigned Op = 0; Op != NumArgOperands; ++Op)
2873       pushValueAndType(FuncletPad.getArgOperand(Op), InstID, Vals);
2874     break;
2875   }
2876   case Instruction::CatchSwitch: {
2877     Code = bitc::FUNC_CODE_INST_CATCHSWITCH;
2878     const auto &CatchSwitch = cast<CatchSwitchInst>(I);
2879 
2880     pushValue(CatchSwitch.getParentPad(), InstID, Vals);
2881 
2882     unsigned NumHandlers = CatchSwitch.getNumHandlers();
2883     Vals.push_back(NumHandlers);
2884     for (const BasicBlock *CatchPadBB : CatchSwitch.handlers())
2885       Vals.push_back(VE.getValueID(CatchPadBB));
2886 
2887     if (CatchSwitch.hasUnwindDest())
2888       Vals.push_back(VE.getValueID(CatchSwitch.getUnwindDest()));
2889     break;
2890   }
2891   case Instruction::CallBr: {
2892     const CallBrInst *CBI = cast<CallBrInst>(&I);
2893     const Value *Callee = CBI->getCalledOperand();
2894     FunctionType *FTy = CBI->getFunctionType();
2895 
2896     if (CBI->hasOperandBundles())
2897       writeOperandBundles(*CBI, InstID);
2898 
2899     Code = bitc::FUNC_CODE_INST_CALLBR;
2900 
2901     Vals.push_back(VE.getAttributeListID(CBI->getAttributes()));
2902 
2903     Vals.push_back(CBI->getCallingConv() << bitc::CALL_CCONV |
2904                    1 << bitc::CALL_EXPLICIT_TYPE);
2905 
2906     Vals.push_back(VE.getValueID(CBI->getDefaultDest()));
2907     Vals.push_back(CBI->getNumIndirectDests());
2908     for (unsigned i = 0, e = CBI->getNumIndirectDests(); i != e; ++i)
2909       Vals.push_back(VE.getValueID(CBI->getIndirectDest(i)));
2910 
2911     Vals.push_back(VE.getTypeID(FTy));
2912     pushValueAndType(Callee, InstID, Vals);
2913 
2914     // Emit value #'s for the fixed parameters.
2915     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
2916       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
2917 
2918     // Emit type/value pairs for varargs params.
2919     if (FTy->isVarArg()) {
2920       for (unsigned i = FTy->getNumParams(), e = CBI->getNumArgOperands();
2921            i != e; ++i)
2922         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
2923     }
2924     break;
2925   }
2926   case Instruction::Unreachable:
2927     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
2928     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
2929     break;
2930 
2931   case Instruction::PHI: {
2932     const PHINode &PN = cast<PHINode>(I);
2933     Code = bitc::FUNC_CODE_INST_PHI;
2934     // With the newer instruction encoding, forward references could give
2935     // negative valued IDs.  This is most common for PHIs, so we use
2936     // signed VBRs.
2937     SmallVector<uint64_t, 128> Vals64;
2938     Vals64.push_back(VE.getTypeID(PN.getType()));
2939     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
2940       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64);
2941       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
2942     }
2943 
2944     uint64_t Flags = getOptimizationFlags(&I);
2945     if (Flags != 0)
2946       Vals64.push_back(Flags);
2947 
2948     // Emit a Vals64 vector and exit.
2949     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
2950     Vals64.clear();
2951     return;
2952   }
2953 
2954   case Instruction::LandingPad: {
2955     const LandingPadInst &LP = cast<LandingPadInst>(I);
2956     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
2957     Vals.push_back(VE.getTypeID(LP.getType()));
2958     Vals.push_back(LP.isCleanup());
2959     Vals.push_back(LP.getNumClauses());
2960     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
2961       if (LP.isCatch(I))
2962         Vals.push_back(LandingPadInst::Catch);
2963       else
2964         Vals.push_back(LandingPadInst::Filter);
2965       pushValueAndType(LP.getClause(I), InstID, Vals);
2966     }
2967     break;
2968   }
2969 
2970   case Instruction::Alloca: {
2971     Code = bitc::FUNC_CODE_INST_ALLOCA;
2972     const AllocaInst &AI = cast<AllocaInst>(I);
2973     Vals.push_back(VE.getTypeID(AI.getAllocatedType()));
2974     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2975     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
2976     using APV = AllocaPackedValues;
2977     unsigned Record = 0;
2978     Bitfield::set<APV::Align>(Record, getEncodedAlign(AI.getAlign()));
2979     Bitfield::set<APV::UsedWithInAlloca>(Record, AI.isUsedWithInAlloca());
2980     Bitfield::set<APV::ExplicitType>(Record, true);
2981     Bitfield::set<APV::SwiftError>(Record, AI.isSwiftError());
2982     Vals.push_back(Record);
2983     break;
2984   }
2985 
2986   case Instruction::Load:
2987     if (cast<LoadInst>(I).isAtomic()) {
2988       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
2989       pushValueAndType(I.getOperand(0), InstID, Vals);
2990     } else {
2991       Code = bitc::FUNC_CODE_INST_LOAD;
2992       if (!pushValueAndType(I.getOperand(0), InstID, Vals)) // ptr
2993         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
2994     }
2995     Vals.push_back(VE.getTypeID(I.getType()));
2996     Vals.push_back(getEncodedAlign(cast<LoadInst>(I).getAlign()));
2997     Vals.push_back(cast<LoadInst>(I).isVolatile());
2998     if (cast<LoadInst>(I).isAtomic()) {
2999       Vals.push_back(getEncodedOrdering(cast<LoadInst>(I).getOrdering()));
3000       Vals.push_back(getEncodedSyncScopeID(cast<LoadInst>(I).getSyncScopeID()));
3001     }
3002     break;
3003   case Instruction::Store:
3004     if (cast<StoreInst>(I).isAtomic())
3005       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
3006     else
3007       Code = bitc::FUNC_CODE_INST_STORE;
3008     pushValueAndType(I.getOperand(1), InstID, Vals); // ptrty + ptr
3009     pushValueAndType(I.getOperand(0), InstID, Vals); // valty + val
3010     Vals.push_back(getEncodedAlign(cast<StoreInst>(I).getAlign()));
3011     Vals.push_back(cast<StoreInst>(I).isVolatile());
3012     if (cast<StoreInst>(I).isAtomic()) {
3013       Vals.push_back(getEncodedOrdering(cast<StoreInst>(I).getOrdering()));
3014       Vals.push_back(
3015           getEncodedSyncScopeID(cast<StoreInst>(I).getSyncScopeID()));
3016     }
3017     break;
3018   case Instruction::AtomicCmpXchg:
3019     Code = bitc::FUNC_CODE_INST_CMPXCHG;
3020     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
3021     pushValueAndType(I.getOperand(1), InstID, Vals); // cmp.
3022     pushValue(I.getOperand(2), InstID, Vals);        // newval.
3023     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
3024     Vals.push_back(
3025         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
3026     Vals.push_back(
3027         getEncodedSyncScopeID(cast<AtomicCmpXchgInst>(I).getSyncScopeID()));
3028     Vals.push_back(
3029         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
3030     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
3031     break;
3032   case Instruction::AtomicRMW:
3033     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
3034     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
3035     pushValue(I.getOperand(1), InstID, Vals);        // val.
3036     Vals.push_back(
3037         getEncodedRMWOperation(cast<AtomicRMWInst>(I).getOperation()));
3038     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
3039     Vals.push_back(getEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
3040     Vals.push_back(
3041         getEncodedSyncScopeID(cast<AtomicRMWInst>(I).getSyncScopeID()));
3042     break;
3043   case Instruction::Fence:
3044     Code = bitc::FUNC_CODE_INST_FENCE;
3045     Vals.push_back(getEncodedOrdering(cast<FenceInst>(I).getOrdering()));
3046     Vals.push_back(getEncodedSyncScopeID(cast<FenceInst>(I).getSyncScopeID()));
3047     break;
3048   case Instruction::Call: {
3049     const CallInst &CI = cast<CallInst>(I);
3050     FunctionType *FTy = CI.getFunctionType();
3051 
3052     if (CI.hasOperandBundles())
3053       writeOperandBundles(CI, InstID);
3054 
3055     Code = bitc::FUNC_CODE_INST_CALL;
3056 
3057     Vals.push_back(VE.getAttributeListID(CI.getAttributes()));
3058 
3059     unsigned Flags = getOptimizationFlags(&I);
3060     Vals.push_back(CI.getCallingConv() << bitc::CALL_CCONV |
3061                    unsigned(CI.isTailCall()) << bitc::CALL_TAIL |
3062                    unsigned(CI.isMustTailCall()) << bitc::CALL_MUSTTAIL |
3063                    1 << bitc::CALL_EXPLICIT_TYPE |
3064                    unsigned(CI.isNoTailCall()) << bitc::CALL_NOTAIL |
3065                    unsigned(Flags != 0) << bitc::CALL_FMF);
3066     if (Flags != 0)
3067       Vals.push_back(Flags);
3068 
3069     Vals.push_back(VE.getTypeID(FTy));
3070     pushValueAndType(CI.getCalledOperand(), InstID, Vals); // Callee
3071 
3072     // Emit value #'s for the fixed parameters.
3073     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
3074       // Check for labels (can happen with asm labels).
3075       if (FTy->getParamType(i)->isLabelTy())
3076         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
3077       else
3078         pushValue(CI.getArgOperand(i), InstID, Vals); // fixed param.
3079     }
3080 
3081     // Emit type/value pairs for varargs params.
3082     if (FTy->isVarArg()) {
3083       for (unsigned i = FTy->getNumParams(), e = CI.getNumArgOperands();
3084            i != e; ++i)
3085         pushValueAndType(CI.getArgOperand(i), InstID, Vals); // varargs
3086     }
3087     break;
3088   }
3089   case Instruction::VAArg:
3090     Code = bitc::FUNC_CODE_INST_VAARG;
3091     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
3092     pushValue(I.getOperand(0), InstID, Vals);                   // valist.
3093     Vals.push_back(VE.getTypeID(I.getType())); // restype.
3094     break;
3095   case Instruction::Freeze:
3096     Code = bitc::FUNC_CODE_INST_FREEZE;
3097     pushValueAndType(I.getOperand(0), InstID, Vals);
3098     break;
3099   }
3100 
3101   Stream.EmitRecord(Code, Vals, AbbrevToUse);
3102   Vals.clear();
3103 }
3104 
3105 /// Write a GlobalValue VST to the module. The purpose of this data structure is
3106 /// to allow clients to efficiently find the function body.
3107 void ModuleBitcodeWriter::writeGlobalValueSymbolTable(
3108   DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3109   // Get the offset of the VST we are writing, and backpatch it into
3110   // the VST forward declaration record.
3111   uint64_t VSTOffset = Stream.GetCurrentBitNo();
3112   // The BitcodeStartBit was the stream offset of the identification block.
3113   VSTOffset -= bitcodeStartBit();
3114   assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
3115   // Note that we add 1 here because the offset is relative to one word
3116   // before the start of the identification block, which was historically
3117   // always the start of the regular bitcode header.
3118   Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32 + 1);
3119 
3120   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3121 
3122   auto Abbv = std::make_shared<BitCodeAbbrev>();
3123   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
3124   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
3125   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
3126   unsigned FnEntryAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3127 
3128   for (const Function &F : M) {
3129     uint64_t Record[2];
3130 
3131     if (F.isDeclaration())
3132       continue;
3133 
3134     Record[0] = VE.getValueID(&F);
3135 
3136     // Save the word offset of the function (from the start of the
3137     // actual bitcode written to the stream).
3138     uint64_t BitcodeIndex = FunctionToBitcodeIndex[&F] - bitcodeStartBit();
3139     assert((BitcodeIndex & 31) == 0 && "function block not 32-bit aligned");
3140     // Note that we add 1 here because the offset is relative to one word
3141     // before the start of the identification block, which was historically
3142     // always the start of the regular bitcode header.
3143     Record[1] = BitcodeIndex / 32 + 1;
3144 
3145     Stream.EmitRecord(bitc::VST_CODE_FNENTRY, Record, FnEntryAbbrev);
3146   }
3147 
3148   Stream.ExitBlock();
3149 }
3150 
3151 /// Emit names for arguments, instructions and basic blocks in a function.
3152 void ModuleBitcodeWriter::writeFunctionLevelValueSymbolTable(
3153     const ValueSymbolTable &VST) {
3154   if (VST.empty())
3155     return;
3156 
3157   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3158 
3159   // FIXME: Set up the abbrev, we know how many values there are!
3160   // FIXME: We know if the type names can use 7-bit ascii.
3161   SmallVector<uint64_t, 64> NameVals;
3162 
3163   for (const ValueName &Name : VST) {
3164     // Figure out the encoding to use for the name.
3165     StringEncoding Bits = getStringEncoding(Name.getKey());
3166 
3167     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
3168     NameVals.push_back(VE.getValueID(Name.getValue()));
3169 
3170     // VST_CODE_ENTRY:   [valueid, namechar x N]
3171     // VST_CODE_BBENTRY: [bbid, namechar x N]
3172     unsigned Code;
3173     if (isa<BasicBlock>(Name.getValue())) {
3174       Code = bitc::VST_CODE_BBENTRY;
3175       if (Bits == SE_Char6)
3176         AbbrevToUse = VST_BBENTRY_6_ABBREV;
3177     } else {
3178       Code = bitc::VST_CODE_ENTRY;
3179       if (Bits == SE_Char6)
3180         AbbrevToUse = VST_ENTRY_6_ABBREV;
3181       else if (Bits == SE_Fixed7)
3182         AbbrevToUse = VST_ENTRY_7_ABBREV;
3183     }
3184 
3185     for (const auto P : Name.getKey())
3186       NameVals.push_back((unsigned char)P);
3187 
3188     // Emit the finished record.
3189     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
3190     NameVals.clear();
3191   }
3192 
3193   Stream.ExitBlock();
3194 }
3195 
3196 void ModuleBitcodeWriter::writeUseList(UseListOrder &&Order) {
3197   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
3198   unsigned Code;
3199   if (isa<BasicBlock>(Order.V))
3200     Code = bitc::USELIST_CODE_BB;
3201   else
3202     Code = bitc::USELIST_CODE_DEFAULT;
3203 
3204   SmallVector<uint64_t, 64> Record(Order.Shuffle.begin(), Order.Shuffle.end());
3205   Record.push_back(VE.getValueID(Order.V));
3206   Stream.EmitRecord(Code, Record);
3207 }
3208 
3209 void ModuleBitcodeWriter::writeUseListBlock(const Function *F) {
3210   assert(VE.shouldPreserveUseListOrder() &&
3211          "Expected to be preserving use-list order");
3212 
3213   auto hasMore = [&]() {
3214     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
3215   };
3216   if (!hasMore())
3217     // Nothing to do.
3218     return;
3219 
3220   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
3221   while (hasMore()) {
3222     writeUseList(std::move(VE.UseListOrders.back()));
3223     VE.UseListOrders.pop_back();
3224   }
3225   Stream.ExitBlock();
3226 }
3227 
3228 /// Emit a function body to the module stream.
3229 void ModuleBitcodeWriter::writeFunction(
3230     const Function &F,
3231     DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3232   // Save the bitcode index of the start of this function block for recording
3233   // in the VST.
3234   FunctionToBitcodeIndex[&F] = Stream.GetCurrentBitNo();
3235 
3236   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
3237   VE.incorporateFunction(F);
3238 
3239   SmallVector<unsigned, 64> Vals;
3240 
3241   // Emit the number of basic blocks, so the reader can create them ahead of
3242   // time.
3243   Vals.push_back(VE.getBasicBlocks().size());
3244   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
3245   Vals.clear();
3246 
3247   // If there are function-local constants, emit them now.
3248   unsigned CstStart, CstEnd;
3249   VE.getFunctionConstantRange(CstStart, CstEnd);
3250   writeConstants(CstStart, CstEnd, false);
3251 
3252   // If there is function-local metadata, emit it now.
3253   writeFunctionMetadata(F);
3254 
3255   // Keep a running idea of what the instruction ID is.
3256   unsigned InstID = CstEnd;
3257 
3258   bool NeedsMetadataAttachment = F.hasMetadata();
3259 
3260   DILocation *LastDL = nullptr;
3261   // Finally, emit all the instructions, in order.
3262   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
3263     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
3264          I != E; ++I) {
3265       writeInstruction(*I, InstID, Vals);
3266 
3267       if (!I->getType()->isVoidTy())
3268         ++InstID;
3269 
3270       // If the instruction has metadata, write a metadata attachment later.
3271       NeedsMetadataAttachment |= I->hasMetadataOtherThanDebugLoc();
3272 
3273       // If the instruction has a debug location, emit it.
3274       DILocation *DL = I->getDebugLoc();
3275       if (!DL)
3276         continue;
3277 
3278       if (DL == LastDL) {
3279         // Just repeat the same debug loc as last time.
3280         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
3281         continue;
3282       }
3283 
3284       Vals.push_back(DL->getLine());
3285       Vals.push_back(DL->getColumn());
3286       Vals.push_back(VE.getMetadataOrNullID(DL->getScope()));
3287       Vals.push_back(VE.getMetadataOrNullID(DL->getInlinedAt()));
3288       Vals.push_back(DL->isImplicitCode());
3289       Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
3290       Vals.clear();
3291 
3292       LastDL = DL;
3293     }
3294 
3295   // Emit names for all the instructions etc.
3296   if (auto *Symtab = F.getValueSymbolTable())
3297     writeFunctionLevelValueSymbolTable(*Symtab);
3298 
3299   if (NeedsMetadataAttachment)
3300     writeFunctionMetadataAttachment(F);
3301   if (VE.shouldPreserveUseListOrder())
3302     writeUseListBlock(&F);
3303   VE.purgeFunction();
3304   Stream.ExitBlock();
3305 }
3306 
3307 // Emit blockinfo, which defines the standard abbreviations etc.
3308 void ModuleBitcodeWriter::writeBlockInfo() {
3309   // We only want to emit block info records for blocks that have multiple
3310   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
3311   // Other blocks can define their abbrevs inline.
3312   Stream.EnterBlockInfoBlock();
3313 
3314   { // 8-bit fixed-width VST_CODE_ENTRY/VST_CODE_BBENTRY strings.
3315     auto Abbv = std::make_shared<BitCodeAbbrev>();
3316     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
3317     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3318     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3319     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3320     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3321         VST_ENTRY_8_ABBREV)
3322       llvm_unreachable("Unexpected abbrev ordering!");
3323   }
3324 
3325   { // 7-bit fixed width VST_CODE_ENTRY strings.
3326     auto Abbv = std::make_shared<BitCodeAbbrev>();
3327     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3328     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3329     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3330     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3331     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3332         VST_ENTRY_7_ABBREV)
3333       llvm_unreachable("Unexpected abbrev ordering!");
3334   }
3335   { // 6-bit char6 VST_CODE_ENTRY strings.
3336     auto Abbv = std::make_shared<BitCodeAbbrev>();
3337     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3338     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3339     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3340     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3341     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3342         VST_ENTRY_6_ABBREV)
3343       llvm_unreachable("Unexpected abbrev ordering!");
3344   }
3345   { // 6-bit char6 VST_CODE_BBENTRY strings.
3346     auto Abbv = std::make_shared<BitCodeAbbrev>();
3347     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
3348     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3349     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3350     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3351     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3352         VST_BBENTRY_6_ABBREV)
3353       llvm_unreachable("Unexpected abbrev ordering!");
3354   }
3355 
3356   { // SETTYPE abbrev for CONSTANTS_BLOCK.
3357     auto Abbv = std::make_shared<BitCodeAbbrev>();
3358     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
3359     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
3360                               VE.computeBitsRequiredForTypeIndicies()));
3361     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3362         CONSTANTS_SETTYPE_ABBREV)
3363       llvm_unreachable("Unexpected abbrev ordering!");
3364   }
3365 
3366   { // INTEGER abbrev for CONSTANTS_BLOCK.
3367     auto Abbv = std::make_shared<BitCodeAbbrev>();
3368     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
3369     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3370     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3371         CONSTANTS_INTEGER_ABBREV)
3372       llvm_unreachable("Unexpected abbrev ordering!");
3373   }
3374 
3375   { // CE_CAST abbrev for CONSTANTS_BLOCK.
3376     auto Abbv = std::make_shared<BitCodeAbbrev>();
3377     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
3378     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
3379     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
3380                               VE.computeBitsRequiredForTypeIndicies()));
3381     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
3382 
3383     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3384         CONSTANTS_CE_CAST_Abbrev)
3385       llvm_unreachable("Unexpected abbrev ordering!");
3386   }
3387   { // NULL abbrev for CONSTANTS_BLOCK.
3388     auto Abbv = std::make_shared<BitCodeAbbrev>();
3389     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
3390     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3391         CONSTANTS_NULL_Abbrev)
3392       llvm_unreachable("Unexpected abbrev ordering!");
3393   }
3394 
3395   // FIXME: This should only use space for first class types!
3396 
3397   { // INST_LOAD abbrev for FUNCTION_BLOCK.
3398     auto Abbv = std::make_shared<BitCodeAbbrev>();
3399     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
3400     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
3401     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
3402                               VE.computeBitsRequiredForTypeIndicies()));
3403     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
3404     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
3405     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3406         FUNCTION_INST_LOAD_ABBREV)
3407       llvm_unreachable("Unexpected abbrev ordering!");
3408   }
3409   { // INST_UNOP abbrev for FUNCTION_BLOCK.
3410     auto Abbv = std::make_shared<BitCodeAbbrev>();
3411     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3412     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3413     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3414     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3415         FUNCTION_INST_UNOP_ABBREV)
3416       llvm_unreachable("Unexpected abbrev ordering!");
3417   }
3418   { // INST_UNOP_FLAGS abbrev for FUNCTION_BLOCK.
3419     auto Abbv = std::make_shared<BitCodeAbbrev>();
3420     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3421     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3422     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3423     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3424     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3425         FUNCTION_INST_UNOP_FLAGS_ABBREV)
3426       llvm_unreachable("Unexpected abbrev ordering!");
3427   }
3428   { // INST_BINOP abbrev for FUNCTION_BLOCK.
3429     auto Abbv = std::make_shared<BitCodeAbbrev>();
3430     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3431     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3432     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3433     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3434     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3435         FUNCTION_INST_BINOP_ABBREV)
3436       llvm_unreachable("Unexpected abbrev ordering!");
3437   }
3438   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
3439     auto Abbv = std::make_shared<BitCodeAbbrev>();
3440     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3441     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3442     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3443     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3444     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3445     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3446         FUNCTION_INST_BINOP_FLAGS_ABBREV)
3447       llvm_unreachable("Unexpected abbrev ordering!");
3448   }
3449   { // INST_CAST abbrev for FUNCTION_BLOCK.
3450     auto Abbv = std::make_shared<BitCodeAbbrev>();
3451     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
3452     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
3453     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
3454                               VE.computeBitsRequiredForTypeIndicies()));
3455     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
3456     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3457         FUNCTION_INST_CAST_ABBREV)
3458       llvm_unreachable("Unexpected abbrev ordering!");
3459   }
3460 
3461   { // INST_RET abbrev for FUNCTION_BLOCK.
3462     auto Abbv = std::make_shared<BitCodeAbbrev>();
3463     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3464     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3465         FUNCTION_INST_RET_VOID_ABBREV)
3466       llvm_unreachable("Unexpected abbrev ordering!");
3467   }
3468   { // INST_RET abbrev for FUNCTION_BLOCK.
3469     auto Abbv = std::make_shared<BitCodeAbbrev>();
3470     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3471     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
3472     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3473         FUNCTION_INST_RET_VAL_ABBREV)
3474       llvm_unreachable("Unexpected abbrev ordering!");
3475   }
3476   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
3477     auto Abbv = std::make_shared<BitCodeAbbrev>();
3478     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
3479     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3480         FUNCTION_INST_UNREACHABLE_ABBREV)
3481       llvm_unreachable("Unexpected abbrev ordering!");
3482   }
3483   {
3484     auto Abbv = std::make_shared<BitCodeAbbrev>();
3485     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_GEP));
3486     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
3487     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, // dest ty
3488                               Log2_32_Ceil(VE.getTypes().size() + 1)));
3489     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3490     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
3491     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3492         FUNCTION_INST_GEP_ABBREV)
3493       llvm_unreachable("Unexpected abbrev ordering!");
3494   }
3495 
3496   Stream.ExitBlock();
3497 }
3498 
3499 /// Write the module path strings, currently only used when generating
3500 /// a combined index file.
3501 void IndexBitcodeWriter::writeModStrings() {
3502   Stream.EnterSubblock(bitc::MODULE_STRTAB_BLOCK_ID, 3);
3503 
3504   // TODO: See which abbrev sizes we actually need to emit
3505 
3506   // 8-bit fixed-width MST_ENTRY strings.
3507   auto Abbv = std::make_shared<BitCodeAbbrev>();
3508   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3509   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3510   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3511   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3512   unsigned Abbrev8Bit = Stream.EmitAbbrev(std::move(Abbv));
3513 
3514   // 7-bit fixed width MST_ENTRY strings.
3515   Abbv = std::make_shared<BitCodeAbbrev>();
3516   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3517   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3518   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3519   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3520   unsigned Abbrev7Bit = Stream.EmitAbbrev(std::move(Abbv));
3521 
3522   // 6-bit char6 MST_ENTRY strings.
3523   Abbv = std::make_shared<BitCodeAbbrev>();
3524   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3525   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3526   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3527   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3528   unsigned Abbrev6Bit = Stream.EmitAbbrev(std::move(Abbv));
3529 
3530   // Module Hash, 160 bits SHA1. Optionally, emitted after each MST_CODE_ENTRY.
3531   Abbv = std::make_shared<BitCodeAbbrev>();
3532   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_HASH));
3533   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3534   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3535   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3536   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3537   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3538   unsigned AbbrevHash = Stream.EmitAbbrev(std::move(Abbv));
3539 
3540   SmallVector<unsigned, 64> Vals;
3541   forEachModule(
3542       [&](const StringMapEntry<std::pair<uint64_t, ModuleHash>> &MPSE) {
3543         StringRef Key = MPSE.getKey();
3544         const auto &Value = MPSE.getValue();
3545         StringEncoding Bits = getStringEncoding(Key);
3546         unsigned AbbrevToUse = Abbrev8Bit;
3547         if (Bits == SE_Char6)
3548           AbbrevToUse = Abbrev6Bit;
3549         else if (Bits == SE_Fixed7)
3550           AbbrevToUse = Abbrev7Bit;
3551 
3552         Vals.push_back(Value.first);
3553         Vals.append(Key.begin(), Key.end());
3554 
3555         // Emit the finished record.
3556         Stream.EmitRecord(bitc::MST_CODE_ENTRY, Vals, AbbrevToUse);
3557 
3558         // Emit an optional hash for the module now
3559         const auto &Hash = Value.second;
3560         if (llvm::any_of(Hash, [](uint32_t H) { return H; })) {
3561           Vals.assign(Hash.begin(), Hash.end());
3562           // Emit the hash record.
3563           Stream.EmitRecord(bitc::MST_CODE_HASH, Vals, AbbrevHash);
3564         }
3565 
3566         Vals.clear();
3567       });
3568   Stream.ExitBlock();
3569 }
3570 
3571 /// Write the function type metadata related records that need to appear before
3572 /// a function summary entry (whether per-module or combined).
3573 template <typename Fn>
3574 static void writeFunctionTypeMetadataRecords(BitstreamWriter &Stream,
3575                                              FunctionSummary *FS,
3576                                              Fn GetValueID) {
3577   if (!FS->type_tests().empty())
3578     Stream.EmitRecord(bitc::FS_TYPE_TESTS, FS->type_tests());
3579 
3580   SmallVector<uint64_t, 64> Record;
3581 
3582   auto WriteVFuncIdVec = [&](uint64_t Ty,
3583                              ArrayRef<FunctionSummary::VFuncId> VFs) {
3584     if (VFs.empty())
3585       return;
3586     Record.clear();
3587     for (auto &VF : VFs) {
3588       Record.push_back(VF.GUID);
3589       Record.push_back(VF.Offset);
3590     }
3591     Stream.EmitRecord(Ty, Record);
3592   };
3593 
3594   WriteVFuncIdVec(bitc::FS_TYPE_TEST_ASSUME_VCALLS,
3595                   FS->type_test_assume_vcalls());
3596   WriteVFuncIdVec(bitc::FS_TYPE_CHECKED_LOAD_VCALLS,
3597                   FS->type_checked_load_vcalls());
3598 
3599   auto WriteConstVCallVec = [&](uint64_t Ty,
3600                                 ArrayRef<FunctionSummary::ConstVCall> VCs) {
3601     for (auto &VC : VCs) {
3602       Record.clear();
3603       Record.push_back(VC.VFunc.GUID);
3604       Record.push_back(VC.VFunc.Offset);
3605       Record.insert(Record.end(), VC.Args.begin(), VC.Args.end());
3606       Stream.EmitRecord(Ty, Record);
3607     }
3608   };
3609 
3610   WriteConstVCallVec(bitc::FS_TYPE_TEST_ASSUME_CONST_VCALL,
3611                      FS->type_test_assume_const_vcalls());
3612   WriteConstVCallVec(bitc::FS_TYPE_CHECKED_LOAD_CONST_VCALL,
3613                      FS->type_checked_load_const_vcalls());
3614 
3615   auto WriteRange = [&](ConstantRange Range) {
3616     Range = Range.sextOrTrunc(FunctionSummary::ParamAccess::RangeWidth);
3617     assert(Range.getLower().getNumWords() == 1);
3618     assert(Range.getUpper().getNumWords() == 1);
3619     emitSignedInt64(Record, *Range.getLower().getRawData());
3620     emitSignedInt64(Record, *Range.getUpper().getRawData());
3621   };
3622 
3623   if (!FS->paramAccesses().empty()) {
3624     Record.clear();
3625     for (auto &Arg : FS->paramAccesses()) {
3626       size_t UndoSize = Record.size();
3627       Record.push_back(Arg.ParamNo);
3628       WriteRange(Arg.Use);
3629       Record.push_back(Arg.Calls.size());
3630       for (auto &Call : Arg.Calls) {
3631         Record.push_back(Call.ParamNo);
3632         Optional<unsigned> ValueID = GetValueID(Call.Callee);
3633         if (!ValueID) {
3634           // If ValueID is unknown we can't drop just this call, we must drop
3635           // entire parameter.
3636           Record.resize(UndoSize);
3637           break;
3638         }
3639         Record.push_back(*ValueID);
3640         WriteRange(Call.Offsets);
3641       }
3642     }
3643     if (!Record.empty())
3644       Stream.EmitRecord(bitc::FS_PARAM_ACCESS, Record);
3645   }
3646 }
3647 
3648 /// Collect type IDs from type tests used by function.
3649 static void
3650 getReferencedTypeIds(FunctionSummary *FS,
3651                      std::set<GlobalValue::GUID> &ReferencedTypeIds) {
3652   if (!FS->type_tests().empty())
3653     for (auto &TT : FS->type_tests())
3654       ReferencedTypeIds.insert(TT);
3655 
3656   auto GetReferencedTypesFromVFuncIdVec =
3657       [&](ArrayRef<FunctionSummary::VFuncId> VFs) {
3658         for (auto &VF : VFs)
3659           ReferencedTypeIds.insert(VF.GUID);
3660       };
3661 
3662   GetReferencedTypesFromVFuncIdVec(FS->type_test_assume_vcalls());
3663   GetReferencedTypesFromVFuncIdVec(FS->type_checked_load_vcalls());
3664 
3665   auto GetReferencedTypesFromConstVCallVec =
3666       [&](ArrayRef<FunctionSummary::ConstVCall> VCs) {
3667         for (auto &VC : VCs)
3668           ReferencedTypeIds.insert(VC.VFunc.GUID);
3669       };
3670 
3671   GetReferencedTypesFromConstVCallVec(FS->type_test_assume_const_vcalls());
3672   GetReferencedTypesFromConstVCallVec(FS->type_checked_load_const_vcalls());
3673 }
3674 
3675 static void writeWholeProgramDevirtResolutionByArg(
3676     SmallVector<uint64_t, 64> &NameVals, const std::vector<uint64_t> &args,
3677     const WholeProgramDevirtResolution::ByArg &ByArg) {
3678   NameVals.push_back(args.size());
3679   NameVals.insert(NameVals.end(), args.begin(), args.end());
3680 
3681   NameVals.push_back(ByArg.TheKind);
3682   NameVals.push_back(ByArg.Info);
3683   NameVals.push_back(ByArg.Byte);
3684   NameVals.push_back(ByArg.Bit);
3685 }
3686 
3687 static void writeWholeProgramDevirtResolution(
3688     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3689     uint64_t Id, const WholeProgramDevirtResolution &Wpd) {
3690   NameVals.push_back(Id);
3691 
3692   NameVals.push_back(Wpd.TheKind);
3693   NameVals.push_back(StrtabBuilder.add(Wpd.SingleImplName));
3694   NameVals.push_back(Wpd.SingleImplName.size());
3695 
3696   NameVals.push_back(Wpd.ResByArg.size());
3697   for (auto &A : Wpd.ResByArg)
3698     writeWholeProgramDevirtResolutionByArg(NameVals, A.first, A.second);
3699 }
3700 
3701 static void writeTypeIdSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
3702                                      StringTableBuilder &StrtabBuilder,
3703                                      const std::string &Id,
3704                                      const TypeIdSummary &Summary) {
3705   NameVals.push_back(StrtabBuilder.add(Id));
3706   NameVals.push_back(Id.size());
3707 
3708   NameVals.push_back(Summary.TTRes.TheKind);
3709   NameVals.push_back(Summary.TTRes.SizeM1BitWidth);
3710   NameVals.push_back(Summary.TTRes.AlignLog2);
3711   NameVals.push_back(Summary.TTRes.SizeM1);
3712   NameVals.push_back(Summary.TTRes.BitMask);
3713   NameVals.push_back(Summary.TTRes.InlineBits);
3714 
3715   for (auto &W : Summary.WPDRes)
3716     writeWholeProgramDevirtResolution(NameVals, StrtabBuilder, W.first,
3717                                       W.second);
3718 }
3719 
3720 static void writeTypeIdCompatibleVtableSummaryRecord(
3721     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3722     const std::string &Id, const TypeIdCompatibleVtableInfo &Summary,
3723     ValueEnumerator &VE) {
3724   NameVals.push_back(StrtabBuilder.add(Id));
3725   NameVals.push_back(Id.size());
3726 
3727   for (auto &P : Summary) {
3728     NameVals.push_back(P.AddressPointOffset);
3729     NameVals.push_back(VE.getValueID(P.VTableVI.getValue()));
3730   }
3731 }
3732 
3733 // Helper to emit a single function summary record.
3734 void ModuleBitcodeWriterBase::writePerModuleFunctionSummaryRecord(
3735     SmallVector<uint64_t, 64> &NameVals, GlobalValueSummary *Summary,
3736     unsigned ValueID, unsigned FSCallsAbbrev, unsigned FSCallsProfileAbbrev,
3737     const Function &F) {
3738   NameVals.push_back(ValueID);
3739 
3740   FunctionSummary *FS = cast<FunctionSummary>(Summary);
3741 
3742   writeFunctionTypeMetadataRecords(
3743       Stream, FS, [&](const ValueInfo &VI) -> Optional<unsigned> {
3744         return {VE.getValueID(VI.getValue())};
3745       });
3746 
3747   auto SpecialRefCnts = FS->specialRefCounts();
3748   NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
3749   NameVals.push_back(FS->instCount());
3750   NameVals.push_back(getEncodedFFlags(FS->fflags()));
3751   NameVals.push_back(FS->refs().size());
3752   NameVals.push_back(SpecialRefCnts.first);  // rorefcnt
3753   NameVals.push_back(SpecialRefCnts.second); // worefcnt
3754 
3755   for (auto &RI : FS->refs())
3756     NameVals.push_back(VE.getValueID(RI.getValue()));
3757 
3758   bool HasProfileData =
3759       F.hasProfileData() || ForceSummaryEdgesCold != FunctionSummary::FSHT_None;
3760   for (auto &ECI : FS->calls()) {
3761     NameVals.push_back(getValueId(ECI.first));
3762     if (HasProfileData)
3763       NameVals.push_back(static_cast<uint8_t>(ECI.second.Hotness));
3764     else if (WriteRelBFToSummary)
3765       NameVals.push_back(ECI.second.RelBlockFreq);
3766   }
3767 
3768   unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
3769   unsigned Code =
3770       (HasProfileData ? bitc::FS_PERMODULE_PROFILE
3771                       : (WriteRelBFToSummary ? bitc::FS_PERMODULE_RELBF
3772                                              : bitc::FS_PERMODULE));
3773 
3774   // Emit the finished record.
3775   Stream.EmitRecord(Code, NameVals, FSAbbrev);
3776   NameVals.clear();
3777 }
3778 
3779 // Collect the global value references in the given variable's initializer,
3780 // and emit them in a summary record.
3781 void ModuleBitcodeWriterBase::writeModuleLevelReferences(
3782     const GlobalVariable &V, SmallVector<uint64_t, 64> &NameVals,
3783     unsigned FSModRefsAbbrev, unsigned FSModVTableRefsAbbrev) {
3784   auto VI = Index->getValueInfo(V.getGUID());
3785   if (!VI || VI.getSummaryList().empty()) {
3786     // Only declarations should not have a summary (a declaration might however
3787     // have a summary if the def was in module level asm).
3788     assert(V.isDeclaration());
3789     return;
3790   }
3791   auto *Summary = VI.getSummaryList()[0].get();
3792   NameVals.push_back(VE.getValueID(&V));
3793   GlobalVarSummary *VS = cast<GlobalVarSummary>(Summary);
3794   NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
3795   NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
3796 
3797   auto VTableFuncs = VS->vTableFuncs();
3798   if (!VTableFuncs.empty())
3799     NameVals.push_back(VS->refs().size());
3800 
3801   unsigned SizeBeforeRefs = NameVals.size();
3802   for (auto &RI : VS->refs())
3803     NameVals.push_back(VE.getValueID(RI.getValue()));
3804   // Sort the refs for determinism output, the vector returned by FS->refs() has
3805   // been initialized from a DenseSet.
3806   llvm::sort(NameVals.begin() + SizeBeforeRefs, NameVals.end());
3807 
3808   if (VTableFuncs.empty())
3809     Stream.EmitRecord(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS, NameVals,
3810                       FSModRefsAbbrev);
3811   else {
3812     // VTableFuncs pairs should already be sorted by offset.
3813     for (auto &P : VTableFuncs) {
3814       NameVals.push_back(VE.getValueID(P.FuncVI.getValue()));
3815       NameVals.push_back(P.VTableOffset);
3816     }
3817 
3818     Stream.EmitRecord(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS, NameVals,
3819                       FSModVTableRefsAbbrev);
3820   }
3821   NameVals.clear();
3822 }
3823 
3824 /// Emit the per-module summary section alongside the rest of
3825 /// the module's bitcode.
3826 void ModuleBitcodeWriterBase::writePerModuleGlobalValueSummary() {
3827   // By default we compile with ThinLTO if the module has a summary, but the
3828   // client can request full LTO with a module flag.
3829   bool IsThinLTO = true;
3830   if (auto *MD =
3831           mdconst::extract_or_null<ConstantInt>(M.getModuleFlag("ThinLTO")))
3832     IsThinLTO = MD->getZExtValue();
3833   Stream.EnterSubblock(IsThinLTO ? bitc::GLOBALVAL_SUMMARY_BLOCK_ID
3834                                  : bitc::FULL_LTO_GLOBALVAL_SUMMARY_BLOCK_ID,
3835                        4);
3836 
3837   Stream.EmitRecord(
3838       bitc::FS_VERSION,
3839       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
3840 
3841   // Write the index flags.
3842   uint64_t Flags = 0;
3843   // Bits 1-3 are set only in the combined index, skip them.
3844   if (Index->enableSplitLTOUnit())
3845     Flags |= 0x8;
3846   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Flags});
3847 
3848   if (Index->begin() == Index->end()) {
3849     Stream.ExitBlock();
3850     return;
3851   }
3852 
3853   for (const auto &GVI : valueIds()) {
3854     Stream.EmitRecord(bitc::FS_VALUE_GUID,
3855                       ArrayRef<uint64_t>{GVI.second, GVI.first});
3856   }
3857 
3858   // Abbrev for FS_PERMODULE_PROFILE.
3859   auto Abbv = std::make_shared<BitCodeAbbrev>();
3860   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_PROFILE));
3861   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3862   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3863   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3864   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3865   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3866   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
3867   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
3868   // numrefs x valueid, n x (valueid, hotness)
3869   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3870   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3871   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3872 
3873   // Abbrev for FS_PERMODULE or FS_PERMODULE_RELBF.
3874   Abbv = std::make_shared<BitCodeAbbrev>();
3875   if (WriteRelBFToSummary)
3876     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_RELBF));
3877   else
3878     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE));
3879   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3880   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3881   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3882   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3883   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3884   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
3885   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
3886   // numrefs x valueid, n x (valueid [, rel_block_freq])
3887   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3888   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3889   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3890 
3891   // Abbrev for FS_PERMODULE_GLOBALVAR_INIT_REFS.
3892   Abbv = std::make_shared<BitCodeAbbrev>();
3893   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS));
3894   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
3895   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
3896   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));  // valueids
3897   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3898   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3899 
3900   // Abbrev for FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS.
3901   Abbv = std::make_shared<BitCodeAbbrev>();
3902   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS));
3903   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
3904   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
3905   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numrefs
3906   // numrefs x valueid, n x (valueid , offset)
3907   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3908   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3909   unsigned FSModVTableRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3910 
3911   // Abbrev for FS_ALIAS.
3912   Abbv = std::make_shared<BitCodeAbbrev>();
3913   Abbv->Add(BitCodeAbbrevOp(bitc::FS_ALIAS));
3914   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3915   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3916   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3917   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3918 
3919   // Abbrev for FS_TYPE_ID_METADATA
3920   Abbv = std::make_shared<BitCodeAbbrev>();
3921   Abbv->Add(BitCodeAbbrevOp(bitc::FS_TYPE_ID_METADATA));
3922   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid strtab index
3923   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid length
3924   // n x (valueid , offset)
3925   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3926   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3927   unsigned TypeIdCompatibleVtableAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3928 
3929   SmallVector<uint64_t, 64> NameVals;
3930   // Iterate over the list of functions instead of the Index to
3931   // ensure the ordering is stable.
3932   for (const Function &F : M) {
3933     // Summary emission does not support anonymous functions, they have to
3934     // renamed using the anonymous function renaming pass.
3935     if (!F.hasName())
3936       report_fatal_error("Unexpected anonymous function when writing summary");
3937 
3938     ValueInfo VI = Index->getValueInfo(F.getGUID());
3939     if (!VI || VI.getSummaryList().empty()) {
3940       // Only declarations should not have a summary (a declaration might
3941       // however have a summary if the def was in module level asm).
3942       assert(F.isDeclaration());
3943       continue;
3944     }
3945     auto *Summary = VI.getSummaryList()[0].get();
3946     writePerModuleFunctionSummaryRecord(NameVals, Summary, VE.getValueID(&F),
3947                                         FSCallsAbbrev, FSCallsProfileAbbrev, F);
3948   }
3949 
3950   // Capture references from GlobalVariable initializers, which are outside
3951   // of a function scope.
3952   for (const GlobalVariable &G : M.globals())
3953     writeModuleLevelReferences(G, NameVals, FSModRefsAbbrev,
3954                                FSModVTableRefsAbbrev);
3955 
3956   for (const GlobalAlias &A : M.aliases()) {
3957     auto *Aliasee = A.getBaseObject();
3958     if (!Aliasee->hasName())
3959       // Nameless function don't have an entry in the summary, skip it.
3960       continue;
3961     auto AliasId = VE.getValueID(&A);
3962     auto AliaseeId = VE.getValueID(Aliasee);
3963     NameVals.push_back(AliasId);
3964     auto *Summary = Index->getGlobalValueSummary(A);
3965     AliasSummary *AS = cast<AliasSummary>(Summary);
3966     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
3967     NameVals.push_back(AliaseeId);
3968     Stream.EmitRecord(bitc::FS_ALIAS, NameVals, FSAliasAbbrev);
3969     NameVals.clear();
3970   }
3971 
3972   for (auto &S : Index->typeIdCompatibleVtableMap()) {
3973     writeTypeIdCompatibleVtableSummaryRecord(NameVals, StrtabBuilder, S.first,
3974                                              S.second, VE);
3975     Stream.EmitRecord(bitc::FS_TYPE_ID_METADATA, NameVals,
3976                       TypeIdCompatibleVtableAbbrev);
3977     NameVals.clear();
3978   }
3979 
3980   Stream.EmitRecord(bitc::FS_BLOCK_COUNT,
3981                     ArrayRef<uint64_t>{Index->getBlockCount()});
3982 
3983   Stream.ExitBlock();
3984 }
3985 
3986 /// Emit the combined summary section into the combined index file.
3987 void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
3988   Stream.EnterSubblock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID, 3);
3989   Stream.EmitRecord(
3990       bitc::FS_VERSION,
3991       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
3992 
3993   // Write the index flags.
3994   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Index.getFlags()});
3995 
3996   for (const auto &GVI : valueIds()) {
3997     Stream.EmitRecord(bitc::FS_VALUE_GUID,
3998                       ArrayRef<uint64_t>{GVI.second, GVI.first});
3999   }
4000 
4001   // Abbrev for FS_COMBINED.
4002   auto Abbv = std::make_shared<BitCodeAbbrev>();
4003   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED));
4004   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4005   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4006   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4007   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4008   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4009   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
4010   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4011   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4012   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4013   // numrefs x valueid, n x (valueid)
4014   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4015   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4016   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4017 
4018   // Abbrev for FS_COMBINED_PROFILE.
4019   Abbv = std::make_shared<BitCodeAbbrev>();
4020   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_PROFILE));
4021   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4022   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4023   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4024   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4025   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4026   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
4027   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4028   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4029   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4030   // numrefs x valueid, n x (valueid, hotness)
4031   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4032   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4033   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4034 
4035   // Abbrev for FS_COMBINED_GLOBALVAR_INIT_REFS.
4036   Abbv = std::make_shared<BitCodeAbbrev>();
4037   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS));
4038   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4039   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4040   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4041   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));    // valueids
4042   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4043   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4044 
4045   // Abbrev for FS_COMBINED_ALIAS.
4046   Abbv = std::make_shared<BitCodeAbbrev>();
4047   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_ALIAS));
4048   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4049   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4050   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4051   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4052   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4053 
4054   // The aliases are emitted as a post-pass, and will point to the value
4055   // id of the aliasee. Save them in a vector for post-processing.
4056   SmallVector<AliasSummary *, 64> Aliases;
4057 
4058   // Save the value id for each summary for alias emission.
4059   DenseMap<const GlobalValueSummary *, unsigned> SummaryToValueIdMap;
4060 
4061   SmallVector<uint64_t, 64> NameVals;
4062 
4063   // Set that will be populated during call to writeFunctionTypeMetadataRecords
4064   // with the type ids referenced by this index file.
4065   std::set<GlobalValue::GUID> ReferencedTypeIds;
4066 
4067   // For local linkage, we also emit the original name separately
4068   // immediately after the record.
4069   auto MaybeEmitOriginalName = [&](GlobalValueSummary &S) {
4070     if (!GlobalValue::isLocalLinkage(S.linkage()))
4071       return;
4072     NameVals.push_back(S.getOriginalName());
4073     Stream.EmitRecord(bitc::FS_COMBINED_ORIGINAL_NAME, NameVals);
4074     NameVals.clear();
4075   };
4076 
4077   std::set<GlobalValue::GUID> DefOrUseGUIDs;
4078   forEachSummary([&](GVInfo I, bool IsAliasee) {
4079     GlobalValueSummary *S = I.second;
4080     assert(S);
4081     DefOrUseGUIDs.insert(I.first);
4082     for (const ValueInfo &VI : S->refs())
4083       DefOrUseGUIDs.insert(VI.getGUID());
4084 
4085     auto ValueId = getValueId(I.first);
4086     assert(ValueId);
4087     SummaryToValueIdMap[S] = *ValueId;
4088 
4089     // If this is invoked for an aliasee, we want to record the above
4090     // mapping, but then not emit a summary entry (if the aliasee is
4091     // to be imported, we will invoke this separately with IsAliasee=false).
4092     if (IsAliasee)
4093       return;
4094 
4095     if (auto *AS = dyn_cast<AliasSummary>(S)) {
4096       // Will process aliases as a post-pass because the reader wants all
4097       // global to be loaded first.
4098       Aliases.push_back(AS);
4099       return;
4100     }
4101 
4102     if (auto *VS = dyn_cast<GlobalVarSummary>(S)) {
4103       NameVals.push_back(*ValueId);
4104       NameVals.push_back(Index.getModuleId(VS->modulePath()));
4105       NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
4106       NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
4107       for (auto &RI : VS->refs()) {
4108         auto RefValueId = getValueId(RI.getGUID());
4109         if (!RefValueId)
4110           continue;
4111         NameVals.push_back(*RefValueId);
4112       }
4113 
4114       // Emit the finished record.
4115       Stream.EmitRecord(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS, NameVals,
4116                         FSModRefsAbbrev);
4117       NameVals.clear();
4118       MaybeEmitOriginalName(*S);
4119       return;
4120     }
4121 
4122     auto GetValueId = [&](const ValueInfo &VI) -> Optional<unsigned> {
4123       GlobalValue::GUID GUID = VI.getGUID();
4124       Optional<unsigned> CallValueId = getValueId(GUID);
4125       if (CallValueId)
4126         return CallValueId;
4127       // For SamplePGO, the indirect call targets for local functions will
4128       // have its original name annotated in profile. We try to find the
4129       // corresponding PGOFuncName as the GUID.
4130       GUID = Index.getGUIDFromOriginalID(GUID);
4131       if (!GUID)
4132         return None;
4133       CallValueId = getValueId(GUID);
4134       if (!CallValueId)
4135         return None;
4136       // The mapping from OriginalId to GUID may return a GUID
4137       // that corresponds to a static variable. Filter it out here.
4138       // This can happen when
4139       // 1) There is a call to a library function which does not have
4140       // a CallValidId;
4141       // 2) There is a static variable with the  OriginalGUID identical
4142       // to the GUID of the library function in 1);
4143       // When this happens, the logic for SamplePGO kicks in and
4144       // the static variable in 2) will be found, which needs to be
4145       // filtered out.
4146       auto *GVSum = Index.getGlobalValueSummary(GUID, false);
4147       if (GVSum && GVSum->getSummaryKind() == GlobalValueSummary::GlobalVarKind)
4148         return None;
4149       return CallValueId;
4150     };
4151 
4152     auto *FS = cast<FunctionSummary>(S);
4153     writeFunctionTypeMetadataRecords(Stream, FS, GetValueId);
4154     getReferencedTypeIds(FS, ReferencedTypeIds);
4155 
4156     NameVals.push_back(*ValueId);
4157     NameVals.push_back(Index.getModuleId(FS->modulePath()));
4158     NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
4159     NameVals.push_back(FS->instCount());
4160     NameVals.push_back(getEncodedFFlags(FS->fflags()));
4161     NameVals.push_back(FS->entryCount());
4162 
4163     // Fill in below
4164     NameVals.push_back(0); // numrefs
4165     NameVals.push_back(0); // rorefcnt
4166     NameVals.push_back(0); // worefcnt
4167 
4168     unsigned Count = 0, RORefCnt = 0, WORefCnt = 0;
4169     for (auto &RI : FS->refs()) {
4170       auto RefValueId = getValueId(RI.getGUID());
4171       if (!RefValueId)
4172         continue;
4173       NameVals.push_back(*RefValueId);
4174       if (RI.isReadOnly())
4175         RORefCnt++;
4176       else if (RI.isWriteOnly())
4177         WORefCnt++;
4178       Count++;
4179     }
4180     NameVals[6] = Count;
4181     NameVals[7] = RORefCnt;
4182     NameVals[8] = WORefCnt;
4183 
4184     bool HasProfileData = false;
4185     for (auto &EI : FS->calls()) {
4186       HasProfileData |=
4187           EI.second.getHotness() != CalleeInfo::HotnessType::Unknown;
4188       if (HasProfileData)
4189         break;
4190     }
4191 
4192     for (auto &EI : FS->calls()) {
4193       // If this GUID doesn't have a value id, it doesn't have a function
4194       // summary and we don't need to record any calls to it.
4195       Optional<unsigned> CallValueId = GetValueId(EI.first);
4196       if (!CallValueId)
4197         continue;
4198       NameVals.push_back(*CallValueId);
4199       if (HasProfileData)
4200         NameVals.push_back(static_cast<uint8_t>(EI.second.Hotness));
4201     }
4202 
4203     unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
4204     unsigned Code =
4205         (HasProfileData ? bitc::FS_COMBINED_PROFILE : bitc::FS_COMBINED);
4206 
4207     // Emit the finished record.
4208     Stream.EmitRecord(Code, NameVals, FSAbbrev);
4209     NameVals.clear();
4210     MaybeEmitOriginalName(*S);
4211   });
4212 
4213   for (auto *AS : Aliases) {
4214     auto AliasValueId = SummaryToValueIdMap[AS];
4215     assert(AliasValueId);
4216     NameVals.push_back(AliasValueId);
4217     NameVals.push_back(Index.getModuleId(AS->modulePath()));
4218     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
4219     auto AliaseeValueId = SummaryToValueIdMap[&AS->getAliasee()];
4220     assert(AliaseeValueId);
4221     NameVals.push_back(AliaseeValueId);
4222 
4223     // Emit the finished record.
4224     Stream.EmitRecord(bitc::FS_COMBINED_ALIAS, NameVals, FSAliasAbbrev);
4225     NameVals.clear();
4226     MaybeEmitOriginalName(*AS);
4227 
4228     if (auto *FS = dyn_cast<FunctionSummary>(&AS->getAliasee()))
4229       getReferencedTypeIds(FS, ReferencedTypeIds);
4230   }
4231 
4232   if (!Index.cfiFunctionDefs().empty()) {
4233     for (auto &S : Index.cfiFunctionDefs()) {
4234       if (DefOrUseGUIDs.count(
4235               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4236         NameVals.push_back(StrtabBuilder.add(S));
4237         NameVals.push_back(S.size());
4238       }
4239     }
4240     if (!NameVals.empty()) {
4241       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DEFS, NameVals);
4242       NameVals.clear();
4243     }
4244   }
4245 
4246   if (!Index.cfiFunctionDecls().empty()) {
4247     for (auto &S : Index.cfiFunctionDecls()) {
4248       if (DefOrUseGUIDs.count(
4249               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4250         NameVals.push_back(StrtabBuilder.add(S));
4251         NameVals.push_back(S.size());
4252       }
4253     }
4254     if (!NameVals.empty()) {
4255       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DECLS, NameVals);
4256       NameVals.clear();
4257     }
4258   }
4259 
4260   // Walk the GUIDs that were referenced, and write the
4261   // corresponding type id records.
4262   for (auto &T : ReferencedTypeIds) {
4263     auto TidIter = Index.typeIds().equal_range(T);
4264     for (auto It = TidIter.first; It != TidIter.second; ++It) {
4265       writeTypeIdSummaryRecord(NameVals, StrtabBuilder, It->second.first,
4266                                It->second.second);
4267       Stream.EmitRecord(bitc::FS_TYPE_ID, NameVals);
4268       NameVals.clear();
4269     }
4270   }
4271 
4272   Stream.EmitRecord(bitc::FS_BLOCK_COUNT,
4273                     ArrayRef<uint64_t>{Index.getBlockCount()});
4274 
4275   Stream.ExitBlock();
4276 }
4277 
4278 /// Create the "IDENTIFICATION_BLOCK_ID" containing a single string with the
4279 /// current llvm version, and a record for the epoch number.
4280 static void writeIdentificationBlock(BitstreamWriter &Stream) {
4281   Stream.EnterSubblock(bitc::IDENTIFICATION_BLOCK_ID, 5);
4282 
4283   // Write the "user readable" string identifying the bitcode producer
4284   auto Abbv = std::make_shared<BitCodeAbbrev>();
4285   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_STRING));
4286   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4287   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
4288   auto StringAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4289   writeStringRecord(Stream, bitc::IDENTIFICATION_CODE_STRING,
4290                     "LLVM" LLVM_VERSION_STRING, StringAbbrev);
4291 
4292   // Write the epoch version
4293   Abbv = std::make_shared<BitCodeAbbrev>();
4294   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_EPOCH));
4295   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
4296   auto EpochAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4297   constexpr std::array<unsigned, 1> Vals = {{bitc::BITCODE_CURRENT_EPOCH}};
4298   Stream.EmitRecord(bitc::IDENTIFICATION_CODE_EPOCH, Vals, EpochAbbrev);
4299   Stream.ExitBlock();
4300 }
4301 
4302 void ModuleBitcodeWriter::writeModuleHash(size_t BlockStartPos) {
4303   // Emit the module's hash.
4304   // MODULE_CODE_HASH: [5*i32]
4305   if (GenerateHash) {
4306     uint32_t Vals[5];
4307     Hasher.update(ArrayRef<uint8_t>((const uint8_t *)&(Buffer)[BlockStartPos],
4308                                     Buffer.size() - BlockStartPos));
4309     StringRef Hash = Hasher.result();
4310     for (int Pos = 0; Pos < 20; Pos += 4) {
4311       Vals[Pos / 4] = support::endian::read32be(Hash.data() + Pos);
4312     }
4313 
4314     // Emit the finished record.
4315     Stream.EmitRecord(bitc::MODULE_CODE_HASH, Vals);
4316 
4317     if (ModHash)
4318       // Save the written hash value.
4319       llvm::copy(Vals, std::begin(*ModHash));
4320   }
4321 }
4322 
4323 void ModuleBitcodeWriter::write() {
4324   writeIdentificationBlock(Stream);
4325 
4326   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4327   size_t BlockStartPos = Buffer.size();
4328 
4329   writeModuleVersion();
4330 
4331   // Emit blockinfo, which defines the standard abbreviations etc.
4332   writeBlockInfo();
4333 
4334   // Emit information describing all of the types in the module.
4335   writeTypeTable();
4336 
4337   // Emit information about attribute groups.
4338   writeAttributeGroupTable();
4339 
4340   // Emit information about parameter attributes.
4341   writeAttributeTable();
4342 
4343   writeComdats();
4344 
4345   // Emit top-level description of module, including target triple, inline asm,
4346   // descriptors for global variables, and function prototype info.
4347   writeModuleInfo();
4348 
4349   // Emit constants.
4350   writeModuleConstants();
4351 
4352   // Emit metadata kind names.
4353   writeModuleMetadataKinds();
4354 
4355   // Emit metadata.
4356   writeModuleMetadata();
4357 
4358   // Emit module-level use-lists.
4359   if (VE.shouldPreserveUseListOrder())
4360     writeUseListBlock(nullptr);
4361 
4362   writeOperandBundleTags();
4363   writeSyncScopeNames();
4364 
4365   // Emit function bodies.
4366   DenseMap<const Function *, uint64_t> FunctionToBitcodeIndex;
4367   for (Module::const_iterator F = M.begin(), E = M.end(); F != E; ++F)
4368     if (!F->isDeclaration())
4369       writeFunction(*F, FunctionToBitcodeIndex);
4370 
4371   // Need to write after the above call to WriteFunction which populates
4372   // the summary information in the index.
4373   if (Index)
4374     writePerModuleGlobalValueSummary();
4375 
4376   writeGlobalValueSymbolTable(FunctionToBitcodeIndex);
4377 
4378   writeModuleHash(BlockStartPos);
4379 
4380   Stream.ExitBlock();
4381 }
4382 
4383 static void writeInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
4384                                uint32_t &Position) {
4385   support::endian::write32le(&Buffer[Position], Value);
4386   Position += 4;
4387 }
4388 
4389 /// If generating a bc file on darwin, we have to emit a
4390 /// header and trailer to make it compatible with the system archiver.  To do
4391 /// this we emit the following header, and then emit a trailer that pads the
4392 /// file out to be a multiple of 16 bytes.
4393 ///
4394 /// struct bc_header {
4395 ///   uint32_t Magic;         // 0x0B17C0DE
4396 ///   uint32_t Version;       // Version, currently always 0.
4397 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
4398 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
4399 ///   uint32_t CPUType;       // CPU specifier.
4400 ///   ... potentially more later ...
4401 /// };
4402 static void emitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
4403                                          const Triple &TT) {
4404   unsigned CPUType = ~0U;
4405 
4406   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
4407   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
4408   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
4409   // specific constants here because they are implicitly part of the Darwin ABI.
4410   enum {
4411     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
4412     DARWIN_CPU_TYPE_X86        = 7,
4413     DARWIN_CPU_TYPE_ARM        = 12,
4414     DARWIN_CPU_TYPE_POWERPC    = 18
4415   };
4416 
4417   Triple::ArchType Arch = TT.getArch();
4418   if (Arch == Triple::x86_64)
4419     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
4420   else if (Arch == Triple::x86)
4421     CPUType = DARWIN_CPU_TYPE_X86;
4422   else if (Arch == Triple::ppc)
4423     CPUType = DARWIN_CPU_TYPE_POWERPC;
4424   else if (Arch == Triple::ppc64)
4425     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
4426   else if (Arch == Triple::arm || Arch == Triple::thumb)
4427     CPUType = DARWIN_CPU_TYPE_ARM;
4428 
4429   // Traditional Bitcode starts after header.
4430   assert(Buffer.size() >= BWH_HeaderSize &&
4431          "Expected header size to be reserved");
4432   unsigned BCOffset = BWH_HeaderSize;
4433   unsigned BCSize = Buffer.size() - BWH_HeaderSize;
4434 
4435   // Write the magic and version.
4436   unsigned Position = 0;
4437   writeInt32ToBuffer(0x0B17C0DE, Buffer, Position);
4438   writeInt32ToBuffer(0, Buffer, Position); // Version.
4439   writeInt32ToBuffer(BCOffset, Buffer, Position);
4440   writeInt32ToBuffer(BCSize, Buffer, Position);
4441   writeInt32ToBuffer(CPUType, Buffer, Position);
4442 
4443   // If the file is not a multiple of 16 bytes, insert dummy padding.
4444   while (Buffer.size() & 15)
4445     Buffer.push_back(0);
4446 }
4447 
4448 /// Helper to write the header common to all bitcode files.
4449 static void writeBitcodeHeader(BitstreamWriter &Stream) {
4450   // Emit the file header.
4451   Stream.Emit((unsigned)'B', 8);
4452   Stream.Emit((unsigned)'C', 8);
4453   Stream.Emit(0x0, 4);
4454   Stream.Emit(0xC, 4);
4455   Stream.Emit(0xE, 4);
4456   Stream.Emit(0xD, 4);
4457 }
4458 
4459 BitcodeWriter::BitcodeWriter(SmallVectorImpl<char> &Buffer, raw_fd_stream *FS)
4460     : Buffer(Buffer), Stream(new BitstreamWriter(Buffer, FS, FlushThreshold)) {
4461   writeBitcodeHeader(*Stream);
4462 }
4463 
4464 BitcodeWriter::~BitcodeWriter() { assert(WroteStrtab); }
4465 
4466 void BitcodeWriter::writeBlob(unsigned Block, unsigned Record, StringRef Blob) {
4467   Stream->EnterSubblock(Block, 3);
4468 
4469   auto Abbv = std::make_shared<BitCodeAbbrev>();
4470   Abbv->Add(BitCodeAbbrevOp(Record));
4471   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
4472   auto AbbrevNo = Stream->EmitAbbrev(std::move(Abbv));
4473 
4474   Stream->EmitRecordWithBlob(AbbrevNo, ArrayRef<uint64_t>{Record}, Blob);
4475 
4476   Stream->ExitBlock();
4477 }
4478 
4479 void BitcodeWriter::writeSymtab() {
4480   assert(!WroteStrtab && !WroteSymtab);
4481 
4482   // If any module has module-level inline asm, we will require a registered asm
4483   // parser for the target so that we can create an accurate symbol table for
4484   // the module.
4485   for (Module *M : Mods) {
4486     if (M->getModuleInlineAsm().empty())
4487       continue;
4488 
4489     std::string Err;
4490     const Triple TT(M->getTargetTriple());
4491     const Target *T = TargetRegistry::lookupTarget(TT.str(), Err);
4492     if (!T || !T->hasMCAsmParser())
4493       return;
4494   }
4495 
4496   WroteSymtab = true;
4497   SmallVector<char, 0> Symtab;
4498   // The irsymtab::build function may be unable to create a symbol table if the
4499   // module is malformed (e.g. it contains an invalid alias). Writing a symbol
4500   // table is not required for correctness, but we still want to be able to
4501   // write malformed modules to bitcode files, so swallow the error.
4502   if (Error E = irsymtab::build(Mods, Symtab, StrtabBuilder, Alloc)) {
4503     consumeError(std::move(E));
4504     return;
4505   }
4506 
4507   writeBlob(bitc::SYMTAB_BLOCK_ID, bitc::SYMTAB_BLOB,
4508             {Symtab.data(), Symtab.size()});
4509 }
4510 
4511 void BitcodeWriter::writeStrtab() {
4512   assert(!WroteStrtab);
4513 
4514   std::vector<char> Strtab;
4515   StrtabBuilder.finalizeInOrder();
4516   Strtab.resize(StrtabBuilder.getSize());
4517   StrtabBuilder.write((uint8_t *)Strtab.data());
4518 
4519   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB,
4520             {Strtab.data(), Strtab.size()});
4521 
4522   WroteStrtab = true;
4523 }
4524 
4525 void BitcodeWriter::copyStrtab(StringRef Strtab) {
4526   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB, Strtab);
4527   WroteStrtab = true;
4528 }
4529 
4530 void BitcodeWriter::writeModule(const Module &M,
4531                                 bool ShouldPreserveUseListOrder,
4532                                 const ModuleSummaryIndex *Index,
4533                                 bool GenerateHash, ModuleHash *ModHash) {
4534   assert(!WroteStrtab);
4535 
4536   // The Mods vector is used by irsymtab::build, which requires non-const
4537   // Modules in case it needs to materialize metadata. But the bitcode writer
4538   // requires that the module is materialized, so we can cast to non-const here,
4539   // after checking that it is in fact materialized.
4540   assert(M.isMaterialized());
4541   Mods.push_back(const_cast<Module *>(&M));
4542 
4543   ModuleBitcodeWriter ModuleWriter(M, Buffer, StrtabBuilder, *Stream,
4544                                    ShouldPreserveUseListOrder, Index,
4545                                    GenerateHash, ModHash);
4546   ModuleWriter.write();
4547 }
4548 
4549 void BitcodeWriter::writeIndex(
4550     const ModuleSummaryIndex *Index,
4551     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4552   IndexBitcodeWriter IndexWriter(*Stream, StrtabBuilder, *Index,
4553                                  ModuleToSummariesForIndex);
4554   IndexWriter.write();
4555 }
4556 
4557 /// Write the specified module to the specified output stream.
4558 void llvm::WriteBitcodeToFile(const Module &M, raw_ostream &Out,
4559                               bool ShouldPreserveUseListOrder,
4560                               const ModuleSummaryIndex *Index,
4561                               bool GenerateHash, ModuleHash *ModHash) {
4562   SmallVector<char, 0> Buffer;
4563   Buffer.reserve(256*1024);
4564 
4565   // If this is darwin or another generic macho target, reserve space for the
4566   // header.
4567   Triple TT(M.getTargetTriple());
4568   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4569     Buffer.insert(Buffer.begin(), BWH_HeaderSize, 0);
4570 
4571   BitcodeWriter Writer(Buffer, dyn_cast<raw_fd_stream>(&Out));
4572   Writer.writeModule(M, ShouldPreserveUseListOrder, Index, GenerateHash,
4573                      ModHash);
4574   Writer.writeSymtab();
4575   Writer.writeStrtab();
4576 
4577   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4578     emitDarwinBCHeaderAndTrailer(Buffer, TT);
4579 
4580   // Write the generated bitstream to "Out".
4581   if (!Buffer.empty())
4582     Out.write((char *)&Buffer.front(), Buffer.size());
4583 }
4584 
4585 void IndexBitcodeWriter::write() {
4586   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4587 
4588   writeModuleVersion();
4589 
4590   // Write the module paths in the combined index.
4591   writeModStrings();
4592 
4593   // Write the summary combined index records.
4594   writeCombinedGlobalValueSummary();
4595 
4596   Stream.ExitBlock();
4597 }
4598 
4599 // Write the specified module summary index to the given raw output stream,
4600 // where it will be written in a new bitcode block. This is used when
4601 // writing the combined index file for ThinLTO. When writing a subset of the
4602 // index for a distributed backend, provide a \p ModuleToSummariesForIndex map.
4603 void llvm::WriteIndexToFile(
4604     const ModuleSummaryIndex &Index, raw_ostream &Out,
4605     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4606   SmallVector<char, 0> Buffer;
4607   Buffer.reserve(256 * 1024);
4608 
4609   BitcodeWriter Writer(Buffer);
4610   Writer.writeIndex(&Index, ModuleToSummariesForIndex);
4611   Writer.writeStrtab();
4612 
4613   Out.write((char *)&Buffer.front(), Buffer.size());
4614 }
4615 
4616 namespace {
4617 
4618 /// Class to manage the bitcode writing for a thin link bitcode file.
4619 class ThinLinkBitcodeWriter : public ModuleBitcodeWriterBase {
4620   /// ModHash is for use in ThinLTO incremental build, generated while writing
4621   /// the module bitcode file.
4622   const ModuleHash *ModHash;
4623 
4624 public:
4625   ThinLinkBitcodeWriter(const Module &M, StringTableBuilder &StrtabBuilder,
4626                         BitstreamWriter &Stream,
4627                         const ModuleSummaryIndex &Index,
4628                         const ModuleHash &ModHash)
4629       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
4630                                 /*ShouldPreserveUseListOrder=*/false, &Index),
4631         ModHash(&ModHash) {}
4632 
4633   void write();
4634 
4635 private:
4636   void writeSimplifiedModuleInfo();
4637 };
4638 
4639 } // end anonymous namespace
4640 
4641 // This function writes a simpilified module info for thin link bitcode file.
4642 // It only contains the source file name along with the name(the offset and
4643 // size in strtab) and linkage for global values. For the global value info
4644 // entry, in order to keep linkage at offset 5, there are three zeros used
4645 // as padding.
4646 void ThinLinkBitcodeWriter::writeSimplifiedModuleInfo() {
4647   SmallVector<unsigned, 64> Vals;
4648   // Emit the module's source file name.
4649   {
4650     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
4651     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
4652     if (Bits == SE_Char6)
4653       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
4654     else if (Bits == SE_Fixed7)
4655       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
4656 
4657     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
4658     auto Abbv = std::make_shared<BitCodeAbbrev>();
4659     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
4660     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4661     Abbv->Add(AbbrevOpToUse);
4662     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4663 
4664     for (const auto P : M.getSourceFileName())
4665       Vals.push_back((unsigned char)P);
4666 
4667     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
4668     Vals.clear();
4669   }
4670 
4671   // Emit the global variable information.
4672   for (const GlobalVariable &GV : M.globals()) {
4673     // GLOBALVAR: [strtab offset, strtab size, 0, 0, 0, linkage]
4674     Vals.push_back(StrtabBuilder.add(GV.getName()));
4675     Vals.push_back(GV.getName().size());
4676     Vals.push_back(0);
4677     Vals.push_back(0);
4678     Vals.push_back(0);
4679     Vals.push_back(getEncodedLinkage(GV));
4680 
4681     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals);
4682     Vals.clear();
4683   }
4684 
4685   // Emit the function proto information.
4686   for (const Function &F : M) {
4687     // FUNCTION:  [strtab offset, strtab size, 0, 0, 0, linkage]
4688     Vals.push_back(StrtabBuilder.add(F.getName()));
4689     Vals.push_back(F.getName().size());
4690     Vals.push_back(0);
4691     Vals.push_back(0);
4692     Vals.push_back(0);
4693     Vals.push_back(getEncodedLinkage(F));
4694 
4695     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals);
4696     Vals.clear();
4697   }
4698 
4699   // Emit the alias information.
4700   for (const GlobalAlias &A : M.aliases()) {
4701     // ALIAS: [strtab offset, strtab size, 0, 0, 0, linkage]
4702     Vals.push_back(StrtabBuilder.add(A.getName()));
4703     Vals.push_back(A.getName().size());
4704     Vals.push_back(0);
4705     Vals.push_back(0);
4706     Vals.push_back(0);
4707     Vals.push_back(getEncodedLinkage(A));
4708 
4709     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals);
4710     Vals.clear();
4711   }
4712 
4713   // Emit the ifunc information.
4714   for (const GlobalIFunc &I : M.ifuncs()) {
4715     // IFUNC: [strtab offset, strtab size, 0, 0, 0, linkage]
4716     Vals.push_back(StrtabBuilder.add(I.getName()));
4717     Vals.push_back(I.getName().size());
4718     Vals.push_back(0);
4719     Vals.push_back(0);
4720     Vals.push_back(0);
4721     Vals.push_back(getEncodedLinkage(I));
4722 
4723     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
4724     Vals.clear();
4725   }
4726 }
4727 
4728 void ThinLinkBitcodeWriter::write() {
4729   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4730 
4731   writeModuleVersion();
4732 
4733   writeSimplifiedModuleInfo();
4734 
4735   writePerModuleGlobalValueSummary();
4736 
4737   // Write module hash.
4738   Stream.EmitRecord(bitc::MODULE_CODE_HASH, ArrayRef<uint32_t>(*ModHash));
4739 
4740   Stream.ExitBlock();
4741 }
4742 
4743 void BitcodeWriter::writeThinLinkBitcode(const Module &M,
4744                                          const ModuleSummaryIndex &Index,
4745                                          const ModuleHash &ModHash) {
4746   assert(!WroteStrtab);
4747 
4748   // The Mods vector is used by irsymtab::build, which requires non-const
4749   // Modules in case it needs to materialize metadata. But the bitcode writer
4750   // requires that the module is materialized, so we can cast to non-const here,
4751   // after checking that it is in fact materialized.
4752   assert(M.isMaterialized());
4753   Mods.push_back(const_cast<Module *>(&M));
4754 
4755   ThinLinkBitcodeWriter ThinLinkWriter(M, StrtabBuilder, *Stream, Index,
4756                                        ModHash);
4757   ThinLinkWriter.write();
4758 }
4759 
4760 // Write the specified thin link bitcode file to the given raw output stream,
4761 // where it will be written in a new bitcode block. This is used when
4762 // writing the per-module index file for ThinLTO.
4763 void llvm::WriteThinLinkBitcodeToFile(const Module &M, raw_ostream &Out,
4764                                       const ModuleSummaryIndex &Index,
4765                                       const ModuleHash &ModHash) {
4766   SmallVector<char, 0> Buffer;
4767   Buffer.reserve(256 * 1024);
4768 
4769   BitcodeWriter Writer(Buffer);
4770   Writer.writeThinLinkBitcode(M, Index, ModHash);
4771   Writer.writeSymtab();
4772   Writer.writeStrtab();
4773 
4774   Out.write((char *)&Buffer.front(), Buffer.size());
4775 }
4776 
4777 static const char *getSectionNameForBitcode(const Triple &T) {
4778   switch (T.getObjectFormat()) {
4779   case Triple::MachO:
4780     return "__LLVM,__bitcode";
4781   case Triple::COFF:
4782   case Triple::ELF:
4783   case Triple::Wasm:
4784   case Triple::UnknownObjectFormat:
4785     return ".llvmbc";
4786   case Triple::GOFF:
4787     llvm_unreachable("GOFF is not yet implemented");
4788     break;
4789   case Triple::XCOFF:
4790     llvm_unreachable("XCOFF is not yet implemented");
4791     break;
4792   }
4793   llvm_unreachable("Unimplemented ObjectFormatType");
4794 }
4795 
4796 static const char *getSectionNameForCommandline(const Triple &T) {
4797   switch (T.getObjectFormat()) {
4798   case Triple::MachO:
4799     return "__LLVM,__cmdline";
4800   case Triple::COFF:
4801   case Triple::ELF:
4802   case Triple::Wasm:
4803   case Triple::UnknownObjectFormat:
4804     return ".llvmcmd";
4805   case Triple::GOFF:
4806     llvm_unreachable("GOFF is not yet implemented");
4807     break;
4808   case Triple::XCOFF:
4809     llvm_unreachable("XCOFF is not yet implemented");
4810     break;
4811   }
4812   llvm_unreachable("Unimplemented ObjectFormatType");
4813 }
4814 
4815 void llvm::EmbedBitcodeInModule(llvm::Module &M, llvm::MemoryBufferRef Buf,
4816                                 bool EmbedBitcode, bool EmbedMarker,
4817                                 const std::vector<uint8_t> *CmdArgs) {
4818   // Save llvm.compiler.used and remove it.
4819   SmallVector<Constant *, 2> UsedArray;
4820   SmallPtrSet<GlobalValue *, 4> UsedGlobals;
4821   Type *UsedElementType = Type::getInt8Ty(M.getContext())->getPointerTo(0);
4822   GlobalVariable *Used = collectUsedGlobalVariables(M, UsedGlobals, true);
4823   for (auto *GV : UsedGlobals) {
4824     if (GV->getName() != "llvm.embedded.module" &&
4825         GV->getName() != "llvm.cmdline")
4826       UsedArray.push_back(
4827           ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
4828   }
4829   if (Used)
4830     Used->eraseFromParent();
4831 
4832   // Embed the bitcode for the llvm module.
4833   std::string Data;
4834   ArrayRef<uint8_t> ModuleData;
4835   Triple T(M.getTargetTriple());
4836 
4837   if (EmbedBitcode) {
4838     if (Buf.getBufferSize() == 0 ||
4839         !isBitcode((const unsigned char *)Buf.getBufferStart(),
4840                    (const unsigned char *)Buf.getBufferEnd())) {
4841       // If the input is LLVM Assembly, bitcode is produced by serializing
4842       // the module. Use-lists order need to be preserved in this case.
4843       llvm::raw_string_ostream OS(Data);
4844       llvm::WriteBitcodeToFile(M, OS, /* ShouldPreserveUseListOrder */ true);
4845       ModuleData =
4846           ArrayRef<uint8_t>((const uint8_t *)OS.str().data(), OS.str().size());
4847     } else
4848       // If the input is LLVM bitcode, write the input byte stream directly.
4849       ModuleData = ArrayRef<uint8_t>((const uint8_t *)Buf.getBufferStart(),
4850                                      Buf.getBufferSize());
4851   }
4852   llvm::Constant *ModuleConstant =
4853       llvm::ConstantDataArray::get(M.getContext(), ModuleData);
4854   llvm::GlobalVariable *GV = new llvm::GlobalVariable(
4855       M, ModuleConstant->getType(), true, llvm::GlobalValue::PrivateLinkage,
4856       ModuleConstant);
4857   GV->setSection(getSectionNameForBitcode(T));
4858   // Set alignment to 1 to prevent padding between two contributions from input
4859   // sections after linking.
4860   GV->setAlignment(Align(1));
4861   UsedArray.push_back(
4862       ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
4863   if (llvm::GlobalVariable *Old =
4864           M.getGlobalVariable("llvm.embedded.module", true)) {
4865     assert(Old->hasOneUse() &&
4866            "llvm.embedded.module can only be used once in llvm.compiler.used");
4867     GV->takeName(Old);
4868     Old->eraseFromParent();
4869   } else {
4870     GV->setName("llvm.embedded.module");
4871   }
4872 
4873   // Skip if only bitcode needs to be embedded.
4874   if (EmbedMarker) {
4875     // Embed command-line options.
4876     ArrayRef<uint8_t> CmdData(const_cast<uint8_t *>(CmdArgs->data()),
4877                               CmdArgs->size());
4878     llvm::Constant *CmdConstant =
4879         llvm::ConstantDataArray::get(M.getContext(), CmdData);
4880     GV = new llvm::GlobalVariable(M, CmdConstant->getType(), true,
4881                                   llvm::GlobalValue::PrivateLinkage,
4882                                   CmdConstant);
4883     GV->setSection(getSectionNameForCommandline(T));
4884     GV->setAlignment(Align(1));
4885     UsedArray.push_back(
4886         ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
4887     if (llvm::GlobalVariable *Old = M.getGlobalVariable("llvm.cmdline", true)) {
4888       assert(Old->hasOneUse() &&
4889              "llvm.cmdline can only be used once in llvm.compiler.used");
4890       GV->takeName(Old);
4891       Old->eraseFromParent();
4892     } else {
4893       GV->setName("llvm.cmdline");
4894     }
4895   }
4896 
4897   if (UsedArray.empty())
4898     return;
4899 
4900   // Recreate llvm.compiler.used.
4901   ArrayType *ATy = ArrayType::get(UsedElementType, UsedArray.size());
4902   auto *NewUsed = new GlobalVariable(
4903       M, ATy, false, llvm::GlobalValue::AppendingLinkage,
4904       llvm::ConstantArray::get(ATy, UsedArray), "llvm.compiler.used");
4905   NewUsed->setSection("llvm.metadata");
4906 }
4907