xref: /llvm-project/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp (revision 6fa35541a0af9d5493e288f574896ee33a8eae92)
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::NoStackProtect:
701     return bitc::ATTR_KIND_NO_STACK_PROTECT;
702   case Attribute::StackProtect:
703     return bitc::ATTR_KIND_STACK_PROTECT;
704   case Attribute::StackProtectReq:
705     return bitc::ATTR_KIND_STACK_PROTECT_REQ;
706   case Attribute::StackProtectStrong:
707     return bitc::ATTR_KIND_STACK_PROTECT_STRONG;
708   case Attribute::SafeStack:
709     return bitc::ATTR_KIND_SAFESTACK;
710   case Attribute::ShadowCallStack:
711     return bitc::ATTR_KIND_SHADOWCALLSTACK;
712   case Attribute::StrictFP:
713     return bitc::ATTR_KIND_STRICT_FP;
714   case Attribute::StructRet:
715     return bitc::ATTR_KIND_STRUCT_RET;
716   case Attribute::SanitizeAddress:
717     return bitc::ATTR_KIND_SANITIZE_ADDRESS;
718   case Attribute::SanitizeHWAddress:
719     return bitc::ATTR_KIND_SANITIZE_HWADDRESS;
720   case Attribute::SanitizeThread:
721     return bitc::ATTR_KIND_SANITIZE_THREAD;
722   case Attribute::SanitizeMemory:
723     return bitc::ATTR_KIND_SANITIZE_MEMORY;
724   case Attribute::SpeculativeLoadHardening:
725     return bitc::ATTR_KIND_SPECULATIVE_LOAD_HARDENING;
726   case Attribute::SwiftError:
727     return bitc::ATTR_KIND_SWIFT_ERROR;
728   case Attribute::SwiftSelf:
729     return bitc::ATTR_KIND_SWIFT_SELF;
730   case Attribute::UWTable:
731     return bitc::ATTR_KIND_UW_TABLE;
732   case Attribute::WillReturn:
733     return bitc::ATTR_KIND_WILLRETURN;
734   case Attribute::WriteOnly:
735     return bitc::ATTR_KIND_WRITEONLY;
736   case Attribute::ZExt:
737     return bitc::ATTR_KIND_Z_EXT;
738   case Attribute::ImmArg:
739     return bitc::ATTR_KIND_IMMARG;
740   case Attribute::SanitizeMemTag:
741     return bitc::ATTR_KIND_SANITIZE_MEMTAG;
742   case Attribute::Preallocated:
743     return bitc::ATTR_KIND_PREALLOCATED;
744   case Attribute::NoUndef:
745     return bitc::ATTR_KIND_NOUNDEF;
746   case Attribute::ByRef:
747     return bitc::ATTR_KIND_BYREF;
748   case Attribute::MustProgress:
749     return bitc::ATTR_KIND_MUSTPROGRESS;
750   case Attribute::EndAttrKinds:
751     llvm_unreachable("Can not encode end-attribute kinds marker.");
752   case Attribute::None:
753     llvm_unreachable("Can not encode none-attribute.");
754   case Attribute::EmptyKey:
755   case Attribute::TombstoneKey:
756     llvm_unreachable("Trying to encode EmptyKey/TombstoneKey");
757   }
758 
759   llvm_unreachable("Trying to encode unknown attribute");
760 }
761 
762 void ModuleBitcodeWriter::writeAttributeGroupTable() {
763   const std::vector<ValueEnumerator::IndexAndAttrSet> &AttrGrps =
764       VE.getAttributeGroups();
765   if (AttrGrps.empty()) return;
766 
767   Stream.EnterSubblock(bitc::PARAMATTR_GROUP_BLOCK_ID, 3);
768 
769   SmallVector<uint64_t, 64> Record;
770   for (ValueEnumerator::IndexAndAttrSet Pair : AttrGrps) {
771     unsigned AttrListIndex = Pair.first;
772     AttributeSet AS = Pair.second;
773     Record.push_back(VE.getAttributeGroupID(Pair));
774     Record.push_back(AttrListIndex);
775 
776     for (Attribute Attr : AS) {
777       if (Attr.isEnumAttribute()) {
778         Record.push_back(0);
779         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
780       } else if (Attr.isIntAttribute()) {
781         Record.push_back(1);
782         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
783         Record.push_back(Attr.getValueAsInt());
784       } else if (Attr.isStringAttribute()) {
785         StringRef Kind = Attr.getKindAsString();
786         StringRef Val = Attr.getValueAsString();
787 
788         Record.push_back(Val.empty() ? 3 : 4);
789         Record.append(Kind.begin(), Kind.end());
790         Record.push_back(0);
791         if (!Val.empty()) {
792           Record.append(Val.begin(), Val.end());
793           Record.push_back(0);
794         }
795       } else {
796         assert(Attr.isTypeAttribute());
797         Type *Ty = Attr.getValueAsType();
798         Record.push_back(Ty ? 6 : 5);
799         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
800         if (Ty)
801           Record.push_back(VE.getTypeID(Attr.getValueAsType()));
802       }
803     }
804 
805     Stream.EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
806     Record.clear();
807   }
808 
809   Stream.ExitBlock();
810 }
811 
812 void ModuleBitcodeWriter::writeAttributeTable() {
813   const std::vector<AttributeList> &Attrs = VE.getAttributeLists();
814   if (Attrs.empty()) return;
815 
816   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
817 
818   SmallVector<uint64_t, 64> Record;
819   for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
820     AttributeList AL = Attrs[i];
821     for (unsigned i = AL.index_begin(), e = AL.index_end(); i != e; ++i) {
822       AttributeSet AS = AL.getAttributes(i);
823       if (AS.hasAttributes())
824         Record.push_back(VE.getAttributeGroupID({i, AS}));
825     }
826 
827     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
828     Record.clear();
829   }
830 
831   Stream.ExitBlock();
832 }
833 
834 /// WriteTypeTable - Write out the type table for a module.
835 void ModuleBitcodeWriter::writeTypeTable() {
836   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
837 
838   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
839   SmallVector<uint64_t, 64> TypeVals;
840 
841   uint64_t NumBits = VE.computeBitsRequiredForTypeIndicies();
842 
843   // Abbrev for TYPE_CODE_POINTER.
844   auto Abbv = std::make_shared<BitCodeAbbrev>();
845   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
846   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
847   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
848   unsigned PtrAbbrev = Stream.EmitAbbrev(std::move(Abbv));
849 
850   // Abbrev for TYPE_CODE_FUNCTION.
851   Abbv = std::make_shared<BitCodeAbbrev>();
852   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
853   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
854   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
855   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
856   unsigned FunctionAbbrev = Stream.EmitAbbrev(std::move(Abbv));
857 
858   // Abbrev for TYPE_CODE_STRUCT_ANON.
859   Abbv = std::make_shared<BitCodeAbbrev>();
860   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
861   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
862   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
863   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
864   unsigned StructAnonAbbrev = Stream.EmitAbbrev(std::move(Abbv));
865 
866   // Abbrev for TYPE_CODE_STRUCT_NAME.
867   Abbv = std::make_shared<BitCodeAbbrev>();
868   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
869   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
870   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
871   unsigned StructNameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
872 
873   // Abbrev for TYPE_CODE_STRUCT_NAMED.
874   Abbv = std::make_shared<BitCodeAbbrev>();
875   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
876   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
877   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
878   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
879   unsigned StructNamedAbbrev = Stream.EmitAbbrev(std::move(Abbv));
880 
881   // Abbrev for TYPE_CODE_ARRAY.
882   Abbv = std::make_shared<BitCodeAbbrev>();
883   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
884   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
885   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
886   unsigned ArrayAbbrev = Stream.EmitAbbrev(std::move(Abbv));
887 
888   // Emit an entry count so the reader can reserve space.
889   TypeVals.push_back(TypeList.size());
890   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
891   TypeVals.clear();
892 
893   // Loop over all of the types, emitting each in turn.
894   for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
895     Type *T = TypeList[i];
896     int AbbrevToUse = 0;
897     unsigned Code = 0;
898 
899     switch (T->getTypeID()) {
900     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;      break;
901     case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;      break;
902     case Type::BFloatTyID:    Code = bitc::TYPE_CODE_BFLOAT;    break;
903     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;     break;
904     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE;    break;
905     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80;  break;
906     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128;     break;
907     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
908     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;     break;
909     case Type::MetadataTyID:  Code = bitc::TYPE_CODE_METADATA;  break;
910     case Type::X86_MMXTyID:   Code = bitc::TYPE_CODE_X86_MMX;   break;
911     case Type::TokenTyID:     Code = bitc::TYPE_CODE_TOKEN;     break;
912     case Type::IntegerTyID:
913       // INTEGER: [width]
914       Code = bitc::TYPE_CODE_INTEGER;
915       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
916       break;
917     case Type::PointerTyID: {
918       PointerType *PTy = cast<PointerType>(T);
919       // POINTER: [pointee type, address space]
920       Code = bitc::TYPE_CODE_POINTER;
921       TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
922       unsigned AddressSpace = PTy->getAddressSpace();
923       TypeVals.push_back(AddressSpace);
924       if (AddressSpace == 0) AbbrevToUse = PtrAbbrev;
925       break;
926     }
927     case Type::FunctionTyID: {
928       FunctionType *FT = cast<FunctionType>(T);
929       // FUNCTION: [isvararg, retty, paramty x N]
930       Code = bitc::TYPE_CODE_FUNCTION;
931       TypeVals.push_back(FT->isVarArg());
932       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
933       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
934         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
935       AbbrevToUse = FunctionAbbrev;
936       break;
937     }
938     case Type::StructTyID: {
939       StructType *ST = cast<StructType>(T);
940       // STRUCT: [ispacked, eltty x N]
941       TypeVals.push_back(ST->isPacked());
942       // Output all of the element types.
943       for (StructType::element_iterator I = ST->element_begin(),
944            E = ST->element_end(); I != E; ++I)
945         TypeVals.push_back(VE.getTypeID(*I));
946 
947       if (ST->isLiteral()) {
948         Code = bitc::TYPE_CODE_STRUCT_ANON;
949         AbbrevToUse = StructAnonAbbrev;
950       } else {
951         if (ST->isOpaque()) {
952           Code = bitc::TYPE_CODE_OPAQUE;
953         } else {
954           Code = bitc::TYPE_CODE_STRUCT_NAMED;
955           AbbrevToUse = StructNamedAbbrev;
956         }
957 
958         // Emit the name if it is present.
959         if (!ST->getName().empty())
960           writeStringRecord(Stream, bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
961                             StructNameAbbrev);
962       }
963       break;
964     }
965     case Type::ArrayTyID: {
966       ArrayType *AT = cast<ArrayType>(T);
967       // ARRAY: [numelts, eltty]
968       Code = bitc::TYPE_CODE_ARRAY;
969       TypeVals.push_back(AT->getNumElements());
970       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
971       AbbrevToUse = ArrayAbbrev;
972       break;
973     }
974     case Type::FixedVectorTyID:
975     case Type::ScalableVectorTyID: {
976       VectorType *VT = cast<VectorType>(T);
977       // VECTOR [numelts, eltty] or
978       //        [numelts, eltty, scalable]
979       Code = bitc::TYPE_CODE_VECTOR;
980       TypeVals.push_back(VT->getElementCount().getKnownMinValue());
981       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
982       if (isa<ScalableVectorType>(VT))
983         TypeVals.push_back(true);
984       break;
985     }
986     }
987 
988     // Emit the finished record.
989     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
990     TypeVals.clear();
991   }
992 
993   Stream.ExitBlock();
994 }
995 
996 static unsigned getEncodedLinkage(const GlobalValue::LinkageTypes Linkage) {
997   switch (Linkage) {
998   case GlobalValue::ExternalLinkage:
999     return 0;
1000   case GlobalValue::WeakAnyLinkage:
1001     return 16;
1002   case GlobalValue::AppendingLinkage:
1003     return 2;
1004   case GlobalValue::InternalLinkage:
1005     return 3;
1006   case GlobalValue::LinkOnceAnyLinkage:
1007     return 18;
1008   case GlobalValue::ExternalWeakLinkage:
1009     return 7;
1010   case GlobalValue::CommonLinkage:
1011     return 8;
1012   case GlobalValue::PrivateLinkage:
1013     return 9;
1014   case GlobalValue::WeakODRLinkage:
1015     return 17;
1016   case GlobalValue::LinkOnceODRLinkage:
1017     return 19;
1018   case GlobalValue::AvailableExternallyLinkage:
1019     return 12;
1020   }
1021   llvm_unreachable("Invalid linkage");
1022 }
1023 
1024 static unsigned getEncodedLinkage(const GlobalValue &GV) {
1025   return getEncodedLinkage(GV.getLinkage());
1026 }
1027 
1028 static uint64_t getEncodedFFlags(FunctionSummary::FFlags Flags) {
1029   uint64_t RawFlags = 0;
1030   RawFlags |= Flags.ReadNone;
1031   RawFlags |= (Flags.ReadOnly << 1);
1032   RawFlags |= (Flags.NoRecurse << 2);
1033   RawFlags |= (Flags.ReturnDoesNotAlias << 3);
1034   RawFlags |= (Flags.NoInline << 4);
1035   RawFlags |= (Flags.AlwaysInline << 5);
1036   return RawFlags;
1037 }
1038 
1039 // Decode the flags for GlobalValue in the summary
1040 static uint64_t getEncodedGVSummaryFlags(GlobalValueSummary::GVFlags Flags) {
1041   uint64_t RawFlags = 0;
1042 
1043   RawFlags |= Flags.NotEligibleToImport; // bool
1044   RawFlags |= (Flags.Live << 1);
1045   RawFlags |= (Flags.DSOLocal << 2);
1046   RawFlags |= (Flags.CanAutoHide << 3);
1047 
1048   // Linkage don't need to be remapped at that time for the summary. Any future
1049   // change to the getEncodedLinkage() function will need to be taken into
1050   // account here as well.
1051   RawFlags = (RawFlags << 4) | Flags.Linkage; // 4 bits
1052 
1053   return RawFlags;
1054 }
1055 
1056 static uint64_t getEncodedGVarFlags(GlobalVarSummary::GVarFlags Flags) {
1057   uint64_t RawFlags = Flags.MaybeReadOnly | (Flags.MaybeWriteOnly << 1) |
1058                       (Flags.Constant << 2) | Flags.VCallVisibility << 3;
1059   return RawFlags;
1060 }
1061 
1062 static unsigned getEncodedVisibility(const GlobalValue &GV) {
1063   switch (GV.getVisibility()) {
1064   case GlobalValue::DefaultVisibility:   return 0;
1065   case GlobalValue::HiddenVisibility:    return 1;
1066   case GlobalValue::ProtectedVisibility: return 2;
1067   }
1068   llvm_unreachable("Invalid visibility");
1069 }
1070 
1071 static unsigned getEncodedDLLStorageClass(const GlobalValue &GV) {
1072   switch (GV.getDLLStorageClass()) {
1073   case GlobalValue::DefaultStorageClass:   return 0;
1074   case GlobalValue::DLLImportStorageClass: return 1;
1075   case GlobalValue::DLLExportStorageClass: return 2;
1076   }
1077   llvm_unreachable("Invalid DLL storage class");
1078 }
1079 
1080 static unsigned getEncodedThreadLocalMode(const GlobalValue &GV) {
1081   switch (GV.getThreadLocalMode()) {
1082     case GlobalVariable::NotThreadLocal:         return 0;
1083     case GlobalVariable::GeneralDynamicTLSModel: return 1;
1084     case GlobalVariable::LocalDynamicTLSModel:   return 2;
1085     case GlobalVariable::InitialExecTLSModel:    return 3;
1086     case GlobalVariable::LocalExecTLSModel:      return 4;
1087   }
1088   llvm_unreachable("Invalid TLS model");
1089 }
1090 
1091 static unsigned getEncodedComdatSelectionKind(const Comdat &C) {
1092   switch (C.getSelectionKind()) {
1093   case Comdat::Any:
1094     return bitc::COMDAT_SELECTION_KIND_ANY;
1095   case Comdat::ExactMatch:
1096     return bitc::COMDAT_SELECTION_KIND_EXACT_MATCH;
1097   case Comdat::Largest:
1098     return bitc::COMDAT_SELECTION_KIND_LARGEST;
1099   case Comdat::NoDuplicates:
1100     return bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES;
1101   case Comdat::SameSize:
1102     return bitc::COMDAT_SELECTION_KIND_SAME_SIZE;
1103   }
1104   llvm_unreachable("Invalid selection kind");
1105 }
1106 
1107 static unsigned getEncodedUnnamedAddr(const GlobalValue &GV) {
1108   switch (GV.getUnnamedAddr()) {
1109   case GlobalValue::UnnamedAddr::None:   return 0;
1110   case GlobalValue::UnnamedAddr::Local:  return 2;
1111   case GlobalValue::UnnamedAddr::Global: return 1;
1112   }
1113   llvm_unreachable("Invalid unnamed_addr");
1114 }
1115 
1116 size_t ModuleBitcodeWriter::addToStrtab(StringRef Str) {
1117   if (GenerateHash)
1118     Hasher.update(Str);
1119   return StrtabBuilder.add(Str);
1120 }
1121 
1122 void ModuleBitcodeWriter::writeComdats() {
1123   SmallVector<unsigned, 64> Vals;
1124   for (const Comdat *C : VE.getComdats()) {
1125     // COMDAT: [strtab offset, strtab size, selection_kind]
1126     Vals.push_back(addToStrtab(C->getName()));
1127     Vals.push_back(C->getName().size());
1128     Vals.push_back(getEncodedComdatSelectionKind(*C));
1129     Stream.EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
1130     Vals.clear();
1131   }
1132 }
1133 
1134 /// Write a record that will eventually hold the word offset of the
1135 /// module-level VST. For now the offset is 0, which will be backpatched
1136 /// after the real VST is written. Saves the bit offset to backpatch.
1137 void ModuleBitcodeWriter::writeValueSymbolTableForwardDecl() {
1138   // Write a placeholder value in for the offset of the real VST,
1139   // which is written after the function blocks so that it can include
1140   // the offset of each function. The placeholder offset will be
1141   // updated when the real VST is written.
1142   auto Abbv = std::make_shared<BitCodeAbbrev>();
1143   Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_VSTOFFSET));
1144   // Blocks are 32-bit aligned, so we can use a 32-bit word offset to
1145   // hold the real VST offset. Must use fixed instead of VBR as we don't
1146   // know how many VBR chunks to reserve ahead of time.
1147   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
1148   unsigned VSTOffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1149 
1150   // Emit the placeholder
1151   uint64_t Vals[] = {bitc::MODULE_CODE_VSTOFFSET, 0};
1152   Stream.EmitRecordWithAbbrev(VSTOffsetAbbrev, Vals);
1153 
1154   // Compute and save the bit offset to the placeholder, which will be
1155   // patched when the real VST is written. We can simply subtract the 32-bit
1156   // fixed size from the current bit number to get the location to backpatch.
1157   VSTOffsetPlaceholder = Stream.GetCurrentBitNo() - 32;
1158 }
1159 
1160 enum StringEncoding { SE_Char6, SE_Fixed7, SE_Fixed8 };
1161 
1162 /// Determine the encoding to use for the given string name and length.
1163 static StringEncoding getStringEncoding(StringRef Str) {
1164   bool isChar6 = true;
1165   for (char C : Str) {
1166     if (isChar6)
1167       isChar6 = BitCodeAbbrevOp::isChar6(C);
1168     if ((unsigned char)C & 128)
1169       // don't bother scanning the rest.
1170       return SE_Fixed8;
1171   }
1172   if (isChar6)
1173     return SE_Char6;
1174   return SE_Fixed7;
1175 }
1176 
1177 /// Emit top-level description of module, including target triple, inline asm,
1178 /// descriptors for global variables, and function prototype info.
1179 /// Returns the bit offset to backpatch with the location of the real VST.
1180 void ModuleBitcodeWriter::writeModuleInfo() {
1181   // Emit various pieces of data attached to a module.
1182   if (!M.getTargetTriple().empty())
1183     writeStringRecord(Stream, bitc::MODULE_CODE_TRIPLE, M.getTargetTriple(),
1184                       0 /*TODO*/);
1185   const std::string &DL = M.getDataLayoutStr();
1186   if (!DL.empty())
1187     writeStringRecord(Stream, bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/);
1188   if (!M.getModuleInlineAsm().empty())
1189     writeStringRecord(Stream, bitc::MODULE_CODE_ASM, M.getModuleInlineAsm(),
1190                       0 /*TODO*/);
1191 
1192   // Emit information about sections and GC, computing how many there are. Also
1193   // compute the maximum alignment value.
1194   std::map<std::string, unsigned> SectionMap;
1195   std::map<std::string, unsigned> GCMap;
1196   MaybeAlign MaxAlignment;
1197   unsigned MaxGlobalType = 0;
1198   const auto UpdateMaxAlignment = [&MaxAlignment](const MaybeAlign A) {
1199     if (A)
1200       MaxAlignment = !MaxAlignment ? *A : std::max(*MaxAlignment, *A);
1201   };
1202   for (const GlobalVariable &GV : M.globals()) {
1203     UpdateMaxAlignment(GV.getAlign());
1204     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getValueType()));
1205     if (GV.hasSection()) {
1206       // Give section names unique ID's.
1207       unsigned &Entry = SectionMap[std::string(GV.getSection())];
1208       if (!Entry) {
1209         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
1210                           0 /*TODO*/);
1211         Entry = SectionMap.size();
1212       }
1213     }
1214   }
1215   for (const Function &F : M) {
1216     UpdateMaxAlignment(F.getAlign());
1217     if (F.hasSection()) {
1218       // Give section names unique ID's.
1219       unsigned &Entry = SectionMap[std::string(F.getSection())];
1220       if (!Entry) {
1221         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
1222                           0 /*TODO*/);
1223         Entry = SectionMap.size();
1224       }
1225     }
1226     if (F.hasGC()) {
1227       // Same for GC names.
1228       unsigned &Entry = GCMap[F.getGC()];
1229       if (!Entry) {
1230         writeStringRecord(Stream, bitc::MODULE_CODE_GCNAME, F.getGC(),
1231                           0 /*TODO*/);
1232         Entry = GCMap.size();
1233       }
1234     }
1235   }
1236 
1237   // Emit abbrev for globals, now that we know # sections and max alignment.
1238   unsigned SimpleGVarAbbrev = 0;
1239   if (!M.global_empty()) {
1240     // Add an abbrev for common globals with no visibility or thread localness.
1241     auto Abbv = std::make_shared<BitCodeAbbrev>();
1242     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
1243     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1244     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1245     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1246                               Log2_32_Ceil(MaxGlobalType+1)));
1247     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddrSpace << 2
1248                                                            //| explicitType << 1
1249                                                            //| constant
1250     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Initializer.
1251     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // Linkage.
1252     if (!MaxAlignment)                                     // Alignment.
1253       Abbv->Add(BitCodeAbbrevOp(0));
1254     else {
1255       unsigned MaxEncAlignment = getEncodedAlign(MaxAlignment);
1256       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1257                                Log2_32_Ceil(MaxEncAlignment+1)));
1258     }
1259     if (SectionMap.empty())                                    // Section.
1260       Abbv->Add(BitCodeAbbrevOp(0));
1261     else
1262       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1263                                Log2_32_Ceil(SectionMap.size()+1)));
1264     // Don't bother emitting vis + thread local.
1265     SimpleGVarAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1266   }
1267 
1268   SmallVector<unsigned, 64> Vals;
1269   // Emit the module's source file name.
1270   {
1271     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
1272     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
1273     if (Bits == SE_Char6)
1274       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
1275     else if (Bits == SE_Fixed7)
1276       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
1277 
1278     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
1279     auto Abbv = std::make_shared<BitCodeAbbrev>();
1280     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
1281     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1282     Abbv->Add(AbbrevOpToUse);
1283     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1284 
1285     for (const auto P : M.getSourceFileName())
1286       Vals.push_back((unsigned char)P);
1287 
1288     // Emit the finished record.
1289     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
1290     Vals.clear();
1291   }
1292 
1293   // Emit the global variable information.
1294   for (const GlobalVariable &GV : M.globals()) {
1295     unsigned AbbrevToUse = 0;
1296 
1297     // GLOBALVAR: [strtab offset, strtab size, type, isconst, initid,
1298     //             linkage, alignment, section, visibility, threadlocal,
1299     //             unnamed_addr, externally_initialized, dllstorageclass,
1300     //             comdat, attributes, DSO_Local]
1301     Vals.push_back(addToStrtab(GV.getName()));
1302     Vals.push_back(GV.getName().size());
1303     Vals.push_back(VE.getTypeID(GV.getValueType()));
1304     Vals.push_back(GV.getType()->getAddressSpace() << 2 | 2 | GV.isConstant());
1305     Vals.push_back(GV.isDeclaration() ? 0 :
1306                    (VE.getValueID(GV.getInitializer()) + 1));
1307     Vals.push_back(getEncodedLinkage(GV));
1308     Vals.push_back(getEncodedAlign(GV.getAlign()));
1309     Vals.push_back(GV.hasSection() ? SectionMap[std::string(GV.getSection())]
1310                                    : 0);
1311     if (GV.isThreadLocal() ||
1312         GV.getVisibility() != GlobalValue::DefaultVisibility ||
1313         GV.getUnnamedAddr() != GlobalValue::UnnamedAddr::None ||
1314         GV.isExternallyInitialized() ||
1315         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
1316         GV.hasComdat() ||
1317         GV.hasAttributes() ||
1318         GV.isDSOLocal() ||
1319         GV.hasPartition()) {
1320       Vals.push_back(getEncodedVisibility(GV));
1321       Vals.push_back(getEncodedThreadLocalMode(GV));
1322       Vals.push_back(getEncodedUnnamedAddr(GV));
1323       Vals.push_back(GV.isExternallyInitialized());
1324       Vals.push_back(getEncodedDLLStorageClass(GV));
1325       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
1326 
1327       auto AL = GV.getAttributesAsList(AttributeList::FunctionIndex);
1328       Vals.push_back(VE.getAttributeListID(AL));
1329 
1330       Vals.push_back(GV.isDSOLocal());
1331       Vals.push_back(addToStrtab(GV.getPartition()));
1332       Vals.push_back(GV.getPartition().size());
1333     } else {
1334       AbbrevToUse = SimpleGVarAbbrev;
1335     }
1336 
1337     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
1338     Vals.clear();
1339   }
1340 
1341   // Emit the function proto information.
1342   for (const Function &F : M) {
1343     // FUNCTION:  [strtab offset, strtab size, type, callingconv, isproto,
1344     //             linkage, paramattrs, alignment, section, visibility, gc,
1345     //             unnamed_addr, prologuedata, dllstorageclass, comdat,
1346     //             prefixdata, personalityfn, DSO_Local, addrspace]
1347     Vals.push_back(addToStrtab(F.getName()));
1348     Vals.push_back(F.getName().size());
1349     Vals.push_back(VE.getTypeID(F.getFunctionType()));
1350     Vals.push_back(F.getCallingConv());
1351     Vals.push_back(F.isDeclaration());
1352     Vals.push_back(getEncodedLinkage(F));
1353     Vals.push_back(VE.getAttributeListID(F.getAttributes()));
1354     Vals.push_back(getEncodedAlign(F.getAlign()));
1355     Vals.push_back(F.hasSection() ? SectionMap[std::string(F.getSection())]
1356                                   : 0);
1357     Vals.push_back(getEncodedVisibility(F));
1358     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
1359     Vals.push_back(getEncodedUnnamedAddr(F));
1360     Vals.push_back(F.hasPrologueData() ? (VE.getValueID(F.getPrologueData()) + 1)
1361                                        : 0);
1362     Vals.push_back(getEncodedDLLStorageClass(F));
1363     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
1364     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
1365                                      : 0);
1366     Vals.push_back(
1367         F.hasPersonalityFn() ? (VE.getValueID(F.getPersonalityFn()) + 1) : 0);
1368 
1369     Vals.push_back(F.isDSOLocal());
1370     Vals.push_back(F.getAddressSpace());
1371     Vals.push_back(addToStrtab(F.getPartition()));
1372     Vals.push_back(F.getPartition().size());
1373 
1374     unsigned AbbrevToUse = 0;
1375     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
1376     Vals.clear();
1377   }
1378 
1379   // Emit the alias information.
1380   for (const GlobalAlias &A : M.aliases()) {
1381     // ALIAS: [strtab offset, strtab size, alias type, aliasee val#, linkage,
1382     //         visibility, dllstorageclass, threadlocal, unnamed_addr,
1383     //         DSO_Local]
1384     Vals.push_back(addToStrtab(A.getName()));
1385     Vals.push_back(A.getName().size());
1386     Vals.push_back(VE.getTypeID(A.getValueType()));
1387     Vals.push_back(A.getType()->getAddressSpace());
1388     Vals.push_back(VE.getValueID(A.getAliasee()));
1389     Vals.push_back(getEncodedLinkage(A));
1390     Vals.push_back(getEncodedVisibility(A));
1391     Vals.push_back(getEncodedDLLStorageClass(A));
1392     Vals.push_back(getEncodedThreadLocalMode(A));
1393     Vals.push_back(getEncodedUnnamedAddr(A));
1394     Vals.push_back(A.isDSOLocal());
1395     Vals.push_back(addToStrtab(A.getPartition()));
1396     Vals.push_back(A.getPartition().size());
1397 
1398     unsigned AbbrevToUse = 0;
1399     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
1400     Vals.clear();
1401   }
1402 
1403   // Emit the ifunc information.
1404   for (const GlobalIFunc &I : M.ifuncs()) {
1405     // IFUNC: [strtab offset, strtab size, ifunc type, address space, resolver
1406     //         val#, linkage, visibility, DSO_Local]
1407     Vals.push_back(addToStrtab(I.getName()));
1408     Vals.push_back(I.getName().size());
1409     Vals.push_back(VE.getTypeID(I.getValueType()));
1410     Vals.push_back(I.getType()->getAddressSpace());
1411     Vals.push_back(VE.getValueID(I.getResolver()));
1412     Vals.push_back(getEncodedLinkage(I));
1413     Vals.push_back(getEncodedVisibility(I));
1414     Vals.push_back(I.isDSOLocal());
1415     Vals.push_back(addToStrtab(I.getPartition()));
1416     Vals.push_back(I.getPartition().size());
1417     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
1418     Vals.clear();
1419   }
1420 
1421   writeValueSymbolTableForwardDecl();
1422 }
1423 
1424 static uint64_t getOptimizationFlags(const Value *V) {
1425   uint64_t Flags = 0;
1426 
1427   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
1428     if (OBO->hasNoSignedWrap())
1429       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
1430     if (OBO->hasNoUnsignedWrap())
1431       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
1432   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
1433     if (PEO->isExact())
1434       Flags |= 1 << bitc::PEO_EXACT;
1435   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
1436     if (FPMO->hasAllowReassoc())
1437       Flags |= bitc::AllowReassoc;
1438     if (FPMO->hasNoNaNs())
1439       Flags |= bitc::NoNaNs;
1440     if (FPMO->hasNoInfs())
1441       Flags |= bitc::NoInfs;
1442     if (FPMO->hasNoSignedZeros())
1443       Flags |= bitc::NoSignedZeros;
1444     if (FPMO->hasAllowReciprocal())
1445       Flags |= bitc::AllowReciprocal;
1446     if (FPMO->hasAllowContract())
1447       Flags |= bitc::AllowContract;
1448     if (FPMO->hasApproxFunc())
1449       Flags |= bitc::ApproxFunc;
1450   }
1451 
1452   return Flags;
1453 }
1454 
1455 void ModuleBitcodeWriter::writeValueAsMetadata(
1456     const ValueAsMetadata *MD, SmallVectorImpl<uint64_t> &Record) {
1457   // Mimic an MDNode with a value as one operand.
1458   Value *V = MD->getValue();
1459   Record.push_back(VE.getTypeID(V->getType()));
1460   Record.push_back(VE.getValueID(V));
1461   Stream.EmitRecord(bitc::METADATA_VALUE, Record, 0);
1462   Record.clear();
1463 }
1464 
1465 void ModuleBitcodeWriter::writeMDTuple(const MDTuple *N,
1466                                        SmallVectorImpl<uint64_t> &Record,
1467                                        unsigned Abbrev) {
1468   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
1469     Metadata *MD = N->getOperand(i);
1470     assert(!(MD && isa<LocalAsMetadata>(MD)) &&
1471            "Unexpected function-local metadata");
1472     Record.push_back(VE.getMetadataOrNullID(MD));
1473   }
1474   Stream.EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
1475                                     : bitc::METADATA_NODE,
1476                     Record, Abbrev);
1477   Record.clear();
1478 }
1479 
1480 unsigned ModuleBitcodeWriter::createDILocationAbbrev() {
1481   // Assume the column is usually under 128, and always output the inlined-at
1482   // location (it's never more expensive than building an array size 1).
1483   auto Abbv = std::make_shared<BitCodeAbbrev>();
1484   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
1485   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1486   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1487   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1488   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1489   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1490   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1491   return Stream.EmitAbbrev(std::move(Abbv));
1492 }
1493 
1494 void ModuleBitcodeWriter::writeDILocation(const DILocation *N,
1495                                           SmallVectorImpl<uint64_t> &Record,
1496                                           unsigned &Abbrev) {
1497   if (!Abbrev)
1498     Abbrev = createDILocationAbbrev();
1499 
1500   Record.push_back(N->isDistinct());
1501   Record.push_back(N->getLine());
1502   Record.push_back(N->getColumn());
1503   Record.push_back(VE.getMetadataID(N->getScope()));
1504   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
1505   Record.push_back(N->isImplicitCode());
1506 
1507   Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
1508   Record.clear();
1509 }
1510 
1511 unsigned ModuleBitcodeWriter::createGenericDINodeAbbrev() {
1512   // Assume the column is usually under 128, and always output the inlined-at
1513   // location (it's never more expensive than building an array size 1).
1514   auto Abbv = std::make_shared<BitCodeAbbrev>();
1515   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
1516   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1517   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1518   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1519   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1520   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1521   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1522   return Stream.EmitAbbrev(std::move(Abbv));
1523 }
1524 
1525 void ModuleBitcodeWriter::writeGenericDINode(const GenericDINode *N,
1526                                              SmallVectorImpl<uint64_t> &Record,
1527                                              unsigned &Abbrev) {
1528   if (!Abbrev)
1529     Abbrev = createGenericDINodeAbbrev();
1530 
1531   Record.push_back(N->isDistinct());
1532   Record.push_back(N->getTag());
1533   Record.push_back(0); // Per-tag version field; unused for now.
1534 
1535   for (auto &I : N->operands())
1536     Record.push_back(VE.getMetadataOrNullID(I));
1537 
1538   Stream.EmitRecord(bitc::METADATA_GENERIC_DEBUG, Record, Abbrev);
1539   Record.clear();
1540 }
1541 
1542 void ModuleBitcodeWriter::writeDISubrange(const DISubrange *N,
1543                                           SmallVectorImpl<uint64_t> &Record,
1544                                           unsigned Abbrev) {
1545   const uint64_t Version = 2 << 1;
1546   Record.push_back((uint64_t)N->isDistinct() | Version);
1547   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1548   Record.push_back(VE.getMetadataOrNullID(N->getRawLowerBound()));
1549   Record.push_back(VE.getMetadataOrNullID(N->getRawUpperBound()));
1550   Record.push_back(VE.getMetadataOrNullID(N->getRawStride()));
1551 
1552   Stream.EmitRecord(bitc::METADATA_SUBRANGE, Record, Abbrev);
1553   Record.clear();
1554 }
1555 
1556 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
1557   if ((int64_t)V >= 0)
1558     Vals.push_back(V << 1);
1559   else
1560     Vals.push_back((-V << 1) | 1);
1561 }
1562 
1563 static void emitWideAPInt(SmallVectorImpl<uint64_t> &Vals, const APInt &A) {
1564   // We have an arbitrary precision integer value to write whose
1565   // bit width is > 64. However, in canonical unsigned integer
1566   // format it is likely that the high bits are going to be zero.
1567   // So, we only write the number of active words.
1568   unsigned NumWords = A.getActiveWords();
1569   const uint64_t *RawData = A.getRawData();
1570   for (unsigned i = 0; i < NumWords; i++)
1571     emitSignedInt64(Vals, RawData[i]);
1572 }
1573 
1574 void ModuleBitcodeWriter::writeDIEnumerator(const DIEnumerator *N,
1575                                             SmallVectorImpl<uint64_t> &Record,
1576                                             unsigned Abbrev) {
1577   const uint64_t IsBigInt = 1 << 2;
1578   Record.push_back(IsBigInt | (N->isUnsigned() << 1) | N->isDistinct());
1579   Record.push_back(N->getValue().getBitWidth());
1580   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1581   emitWideAPInt(Record, N->getValue());
1582 
1583   Stream.EmitRecord(bitc::METADATA_ENUMERATOR, Record, Abbrev);
1584   Record.clear();
1585 }
1586 
1587 void ModuleBitcodeWriter::writeDIBasicType(const DIBasicType *N,
1588                                            SmallVectorImpl<uint64_t> &Record,
1589                                            unsigned Abbrev) {
1590   Record.push_back(N->isDistinct());
1591   Record.push_back(N->getTag());
1592   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1593   Record.push_back(N->getSizeInBits());
1594   Record.push_back(N->getAlignInBits());
1595   Record.push_back(N->getEncoding());
1596   Record.push_back(N->getFlags());
1597 
1598   Stream.EmitRecord(bitc::METADATA_BASIC_TYPE, Record, Abbrev);
1599   Record.clear();
1600 }
1601 
1602 void ModuleBitcodeWriter::writeDIStringType(const DIStringType *N,
1603                                             SmallVectorImpl<uint64_t> &Record,
1604                                             unsigned Abbrev) {
1605   Record.push_back(N->isDistinct());
1606   Record.push_back(N->getTag());
1607   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1608   Record.push_back(VE.getMetadataOrNullID(N->getStringLength()));
1609   Record.push_back(VE.getMetadataOrNullID(N->getStringLengthExp()));
1610   Record.push_back(N->getSizeInBits());
1611   Record.push_back(N->getAlignInBits());
1612   Record.push_back(N->getEncoding());
1613 
1614   Stream.EmitRecord(bitc::METADATA_STRING_TYPE, Record, Abbrev);
1615   Record.clear();
1616 }
1617 
1618 void ModuleBitcodeWriter::writeDIDerivedType(const DIDerivedType *N,
1619                                              SmallVectorImpl<uint64_t> &Record,
1620                                              unsigned Abbrev) {
1621   Record.push_back(N->isDistinct());
1622   Record.push_back(N->getTag());
1623   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1624   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1625   Record.push_back(N->getLine());
1626   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1627   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1628   Record.push_back(N->getSizeInBits());
1629   Record.push_back(N->getAlignInBits());
1630   Record.push_back(N->getOffsetInBits());
1631   Record.push_back(N->getFlags());
1632   Record.push_back(VE.getMetadataOrNullID(N->getExtraData()));
1633 
1634   // DWARF address space is encoded as N->getDWARFAddressSpace() + 1. 0 means
1635   // that there is no DWARF address space associated with DIDerivedType.
1636   if (const auto &DWARFAddressSpace = N->getDWARFAddressSpace())
1637     Record.push_back(*DWARFAddressSpace + 1);
1638   else
1639     Record.push_back(0);
1640 
1641   Stream.EmitRecord(bitc::METADATA_DERIVED_TYPE, Record, Abbrev);
1642   Record.clear();
1643 }
1644 
1645 void ModuleBitcodeWriter::writeDICompositeType(
1646     const DICompositeType *N, SmallVectorImpl<uint64_t> &Record,
1647     unsigned Abbrev) {
1648   const unsigned IsNotUsedInOldTypeRef = 0x2;
1649   Record.push_back(IsNotUsedInOldTypeRef | (unsigned)N->isDistinct());
1650   Record.push_back(N->getTag());
1651   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1652   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1653   Record.push_back(N->getLine());
1654   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1655   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1656   Record.push_back(N->getSizeInBits());
1657   Record.push_back(N->getAlignInBits());
1658   Record.push_back(N->getOffsetInBits());
1659   Record.push_back(N->getFlags());
1660   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1661   Record.push_back(N->getRuntimeLang());
1662   Record.push_back(VE.getMetadataOrNullID(N->getVTableHolder()));
1663   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1664   Record.push_back(VE.getMetadataOrNullID(N->getRawIdentifier()));
1665   Record.push_back(VE.getMetadataOrNullID(N->getDiscriminator()));
1666   Record.push_back(VE.getMetadataOrNullID(N->getRawDataLocation()));
1667   Record.push_back(VE.getMetadataOrNullID(N->getRawAssociated()));
1668   Record.push_back(VE.getMetadataOrNullID(N->getRawAllocated()));
1669   Record.push_back(VE.getMetadataOrNullID(N->getRawRank()));
1670 
1671   Stream.EmitRecord(bitc::METADATA_COMPOSITE_TYPE, Record, Abbrev);
1672   Record.clear();
1673 }
1674 
1675 void ModuleBitcodeWriter::writeDISubroutineType(
1676     const DISubroutineType *N, SmallVectorImpl<uint64_t> &Record,
1677     unsigned Abbrev) {
1678   const unsigned HasNoOldTypeRefs = 0x2;
1679   Record.push_back(HasNoOldTypeRefs | (unsigned)N->isDistinct());
1680   Record.push_back(N->getFlags());
1681   Record.push_back(VE.getMetadataOrNullID(N->getTypeArray().get()));
1682   Record.push_back(N->getCC());
1683 
1684   Stream.EmitRecord(bitc::METADATA_SUBROUTINE_TYPE, Record, Abbrev);
1685   Record.clear();
1686 }
1687 
1688 void ModuleBitcodeWriter::writeDIFile(const DIFile *N,
1689                                       SmallVectorImpl<uint64_t> &Record,
1690                                       unsigned Abbrev) {
1691   Record.push_back(N->isDistinct());
1692   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
1693   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
1694   if (N->getRawChecksum()) {
1695     Record.push_back(N->getRawChecksum()->Kind);
1696     Record.push_back(VE.getMetadataOrNullID(N->getRawChecksum()->Value));
1697   } else {
1698     // Maintain backwards compatibility with the old internal representation of
1699     // CSK_None in ChecksumKind by writing nulls here when Checksum is None.
1700     Record.push_back(0);
1701     Record.push_back(VE.getMetadataOrNullID(nullptr));
1702   }
1703   auto Source = N->getRawSource();
1704   if (Source)
1705     Record.push_back(VE.getMetadataOrNullID(*Source));
1706 
1707   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
1708   Record.clear();
1709 }
1710 
1711 void ModuleBitcodeWriter::writeDICompileUnit(const DICompileUnit *N,
1712                                              SmallVectorImpl<uint64_t> &Record,
1713                                              unsigned Abbrev) {
1714   assert(N->isDistinct() && "Expected distinct compile units");
1715   Record.push_back(/* IsDistinct */ true);
1716   Record.push_back(N->getSourceLanguage());
1717   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1718   Record.push_back(VE.getMetadataOrNullID(N->getRawProducer()));
1719   Record.push_back(N->isOptimized());
1720   Record.push_back(VE.getMetadataOrNullID(N->getRawFlags()));
1721   Record.push_back(N->getRuntimeVersion());
1722   Record.push_back(VE.getMetadataOrNullID(N->getRawSplitDebugFilename()));
1723   Record.push_back(N->getEmissionKind());
1724   Record.push_back(VE.getMetadataOrNullID(N->getEnumTypes().get()));
1725   Record.push_back(VE.getMetadataOrNullID(N->getRetainedTypes().get()));
1726   Record.push_back(/* subprograms */ 0);
1727   Record.push_back(VE.getMetadataOrNullID(N->getGlobalVariables().get()));
1728   Record.push_back(VE.getMetadataOrNullID(N->getImportedEntities().get()));
1729   Record.push_back(N->getDWOId());
1730   Record.push_back(VE.getMetadataOrNullID(N->getMacros().get()));
1731   Record.push_back(N->getSplitDebugInlining());
1732   Record.push_back(N->getDebugInfoForProfiling());
1733   Record.push_back((unsigned)N->getNameTableKind());
1734   Record.push_back(N->getRangesBaseAddress());
1735   Record.push_back(VE.getMetadataOrNullID(N->getRawSysRoot()));
1736   Record.push_back(VE.getMetadataOrNullID(N->getRawSDK()));
1737 
1738   Stream.EmitRecord(bitc::METADATA_COMPILE_UNIT, Record, Abbrev);
1739   Record.clear();
1740 }
1741 
1742 void ModuleBitcodeWriter::writeDISubprogram(const DISubprogram *N,
1743                                             SmallVectorImpl<uint64_t> &Record,
1744                                             unsigned Abbrev) {
1745   const uint64_t HasUnitFlag = 1 << 1;
1746   const uint64_t HasSPFlagsFlag = 1 << 2;
1747   Record.push_back(uint64_t(N->isDistinct()) | HasUnitFlag | HasSPFlagsFlag);
1748   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1749   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1750   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1751   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1752   Record.push_back(N->getLine());
1753   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1754   Record.push_back(N->getScopeLine());
1755   Record.push_back(VE.getMetadataOrNullID(N->getContainingType()));
1756   Record.push_back(N->getSPFlags());
1757   Record.push_back(N->getVirtualIndex());
1758   Record.push_back(N->getFlags());
1759   Record.push_back(VE.getMetadataOrNullID(N->getRawUnit()));
1760   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1761   Record.push_back(VE.getMetadataOrNullID(N->getDeclaration()));
1762   Record.push_back(VE.getMetadataOrNullID(N->getRetainedNodes().get()));
1763   Record.push_back(N->getThisAdjustment());
1764   Record.push_back(VE.getMetadataOrNullID(N->getThrownTypes().get()));
1765 
1766   Stream.EmitRecord(bitc::METADATA_SUBPROGRAM, Record, Abbrev);
1767   Record.clear();
1768 }
1769 
1770 void ModuleBitcodeWriter::writeDILexicalBlock(const DILexicalBlock *N,
1771                                               SmallVectorImpl<uint64_t> &Record,
1772                                               unsigned Abbrev) {
1773   Record.push_back(N->isDistinct());
1774   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1775   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1776   Record.push_back(N->getLine());
1777   Record.push_back(N->getColumn());
1778 
1779   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK, Record, Abbrev);
1780   Record.clear();
1781 }
1782 
1783 void ModuleBitcodeWriter::writeDILexicalBlockFile(
1784     const DILexicalBlockFile *N, SmallVectorImpl<uint64_t> &Record,
1785     unsigned Abbrev) {
1786   Record.push_back(N->isDistinct());
1787   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1788   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1789   Record.push_back(N->getDiscriminator());
1790 
1791   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK_FILE, Record, Abbrev);
1792   Record.clear();
1793 }
1794 
1795 void ModuleBitcodeWriter::writeDICommonBlock(const DICommonBlock *N,
1796                                              SmallVectorImpl<uint64_t> &Record,
1797                                              unsigned Abbrev) {
1798   Record.push_back(N->isDistinct());
1799   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1800   Record.push_back(VE.getMetadataOrNullID(N->getDecl()));
1801   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1802   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1803   Record.push_back(N->getLineNo());
1804 
1805   Stream.EmitRecord(bitc::METADATA_COMMON_BLOCK, Record, Abbrev);
1806   Record.clear();
1807 }
1808 
1809 void ModuleBitcodeWriter::writeDINamespace(const DINamespace *N,
1810                                            SmallVectorImpl<uint64_t> &Record,
1811                                            unsigned Abbrev) {
1812   Record.push_back(N->isDistinct() | N->getExportSymbols() << 1);
1813   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1814   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1815 
1816   Stream.EmitRecord(bitc::METADATA_NAMESPACE, Record, Abbrev);
1817   Record.clear();
1818 }
1819 
1820 void ModuleBitcodeWriter::writeDIMacro(const DIMacro *N,
1821                                        SmallVectorImpl<uint64_t> &Record,
1822                                        unsigned Abbrev) {
1823   Record.push_back(N->isDistinct());
1824   Record.push_back(N->getMacinfoType());
1825   Record.push_back(N->getLine());
1826   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1827   Record.push_back(VE.getMetadataOrNullID(N->getRawValue()));
1828 
1829   Stream.EmitRecord(bitc::METADATA_MACRO, Record, Abbrev);
1830   Record.clear();
1831 }
1832 
1833 void ModuleBitcodeWriter::writeDIMacroFile(const DIMacroFile *N,
1834                                            SmallVectorImpl<uint64_t> &Record,
1835                                            unsigned Abbrev) {
1836   Record.push_back(N->isDistinct());
1837   Record.push_back(N->getMacinfoType());
1838   Record.push_back(N->getLine());
1839   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1840   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1841 
1842   Stream.EmitRecord(bitc::METADATA_MACRO_FILE, Record, Abbrev);
1843   Record.clear();
1844 }
1845 
1846 void ModuleBitcodeWriter::writeDIModule(const DIModule *N,
1847                                         SmallVectorImpl<uint64_t> &Record,
1848                                         unsigned Abbrev) {
1849   Record.push_back(N->isDistinct());
1850   for (auto &I : N->operands())
1851     Record.push_back(VE.getMetadataOrNullID(I));
1852   Record.push_back(N->getLineNo());
1853 
1854   Stream.EmitRecord(bitc::METADATA_MODULE, Record, Abbrev);
1855   Record.clear();
1856 }
1857 
1858 void ModuleBitcodeWriter::writeDITemplateTypeParameter(
1859     const DITemplateTypeParameter *N, SmallVectorImpl<uint64_t> &Record,
1860     unsigned Abbrev) {
1861   Record.push_back(N->isDistinct());
1862   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1863   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1864   Record.push_back(N->isDefault());
1865 
1866   Stream.EmitRecord(bitc::METADATA_TEMPLATE_TYPE, Record, Abbrev);
1867   Record.clear();
1868 }
1869 
1870 void ModuleBitcodeWriter::writeDITemplateValueParameter(
1871     const DITemplateValueParameter *N, SmallVectorImpl<uint64_t> &Record,
1872     unsigned Abbrev) {
1873   Record.push_back(N->isDistinct());
1874   Record.push_back(N->getTag());
1875   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1876   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1877   Record.push_back(N->isDefault());
1878   Record.push_back(VE.getMetadataOrNullID(N->getValue()));
1879 
1880   Stream.EmitRecord(bitc::METADATA_TEMPLATE_VALUE, Record, Abbrev);
1881   Record.clear();
1882 }
1883 
1884 void ModuleBitcodeWriter::writeDIGlobalVariable(
1885     const DIGlobalVariable *N, SmallVectorImpl<uint64_t> &Record,
1886     unsigned Abbrev) {
1887   const uint64_t Version = 2 << 1;
1888   Record.push_back((uint64_t)N->isDistinct() | Version);
1889   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1890   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1891   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1892   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1893   Record.push_back(N->getLine());
1894   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1895   Record.push_back(N->isLocalToUnit());
1896   Record.push_back(N->isDefinition());
1897   Record.push_back(VE.getMetadataOrNullID(N->getStaticDataMemberDeclaration()));
1898   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams()));
1899   Record.push_back(N->getAlignInBits());
1900 
1901   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR, Record, Abbrev);
1902   Record.clear();
1903 }
1904 
1905 void ModuleBitcodeWriter::writeDILocalVariable(
1906     const DILocalVariable *N, SmallVectorImpl<uint64_t> &Record,
1907     unsigned Abbrev) {
1908   // In order to support all possible bitcode formats in BitcodeReader we need
1909   // to distinguish the following cases:
1910   // 1) Record has no artificial tag (Record[1]),
1911   //   has no obsolete inlinedAt field (Record[9]).
1912   //   In this case Record size will be 8, HasAlignment flag is false.
1913   // 2) Record has artificial tag (Record[1]),
1914   //   has no obsolete inlignedAt field (Record[9]).
1915   //   In this case Record size will be 9, HasAlignment flag is false.
1916   // 3) Record has both artificial tag (Record[1]) and
1917   //   obsolete inlignedAt field (Record[9]).
1918   //   In this case Record size will be 10, HasAlignment flag is false.
1919   // 4) Record has neither artificial tag, nor inlignedAt field, but
1920   //   HasAlignment flag is true and Record[8] contains alignment value.
1921   const uint64_t HasAlignmentFlag = 1 << 1;
1922   Record.push_back((uint64_t)N->isDistinct() | HasAlignmentFlag);
1923   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1924   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1925   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1926   Record.push_back(N->getLine());
1927   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1928   Record.push_back(N->getArg());
1929   Record.push_back(N->getFlags());
1930   Record.push_back(N->getAlignInBits());
1931 
1932   Stream.EmitRecord(bitc::METADATA_LOCAL_VAR, Record, Abbrev);
1933   Record.clear();
1934 }
1935 
1936 void ModuleBitcodeWriter::writeDILabel(
1937     const DILabel *N, SmallVectorImpl<uint64_t> &Record,
1938     unsigned Abbrev) {
1939   Record.push_back((uint64_t)N->isDistinct());
1940   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1941   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1942   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1943   Record.push_back(N->getLine());
1944 
1945   Stream.EmitRecord(bitc::METADATA_LABEL, Record, Abbrev);
1946   Record.clear();
1947 }
1948 
1949 void ModuleBitcodeWriter::writeDIExpression(const DIExpression *N,
1950                                             SmallVectorImpl<uint64_t> &Record,
1951                                             unsigned Abbrev) {
1952   Record.reserve(N->getElements().size() + 1);
1953   const uint64_t Version = 3 << 1;
1954   Record.push_back((uint64_t)N->isDistinct() | Version);
1955   Record.append(N->elements_begin(), N->elements_end());
1956 
1957   Stream.EmitRecord(bitc::METADATA_EXPRESSION, Record, Abbrev);
1958   Record.clear();
1959 }
1960 
1961 void ModuleBitcodeWriter::writeDIGlobalVariableExpression(
1962     const DIGlobalVariableExpression *N, SmallVectorImpl<uint64_t> &Record,
1963     unsigned Abbrev) {
1964   Record.push_back(N->isDistinct());
1965   Record.push_back(VE.getMetadataOrNullID(N->getVariable()));
1966   Record.push_back(VE.getMetadataOrNullID(N->getExpression()));
1967 
1968   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR_EXPR, Record, Abbrev);
1969   Record.clear();
1970 }
1971 
1972 void ModuleBitcodeWriter::writeDIObjCProperty(const DIObjCProperty *N,
1973                                               SmallVectorImpl<uint64_t> &Record,
1974                                               unsigned Abbrev) {
1975   Record.push_back(N->isDistinct());
1976   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1977   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1978   Record.push_back(N->getLine());
1979   Record.push_back(VE.getMetadataOrNullID(N->getRawSetterName()));
1980   Record.push_back(VE.getMetadataOrNullID(N->getRawGetterName()));
1981   Record.push_back(N->getAttributes());
1982   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1983 
1984   Stream.EmitRecord(bitc::METADATA_OBJC_PROPERTY, Record, Abbrev);
1985   Record.clear();
1986 }
1987 
1988 void ModuleBitcodeWriter::writeDIImportedEntity(
1989     const DIImportedEntity *N, SmallVectorImpl<uint64_t> &Record,
1990     unsigned Abbrev) {
1991   Record.push_back(N->isDistinct());
1992   Record.push_back(N->getTag());
1993   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1994   Record.push_back(VE.getMetadataOrNullID(N->getEntity()));
1995   Record.push_back(N->getLine());
1996   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1997   Record.push_back(VE.getMetadataOrNullID(N->getRawFile()));
1998 
1999   Stream.EmitRecord(bitc::METADATA_IMPORTED_ENTITY, Record, Abbrev);
2000   Record.clear();
2001 }
2002 
2003 unsigned ModuleBitcodeWriter::createNamedMetadataAbbrev() {
2004   auto Abbv = std::make_shared<BitCodeAbbrev>();
2005   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
2006   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2007   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2008   return Stream.EmitAbbrev(std::move(Abbv));
2009 }
2010 
2011 void ModuleBitcodeWriter::writeNamedMetadata(
2012     SmallVectorImpl<uint64_t> &Record) {
2013   if (M.named_metadata_empty())
2014     return;
2015 
2016   unsigned Abbrev = createNamedMetadataAbbrev();
2017   for (const NamedMDNode &NMD : M.named_metadata()) {
2018     // Write name.
2019     StringRef Str = NMD.getName();
2020     Record.append(Str.bytes_begin(), Str.bytes_end());
2021     Stream.EmitRecord(bitc::METADATA_NAME, Record, Abbrev);
2022     Record.clear();
2023 
2024     // Write named metadata operands.
2025     for (const MDNode *N : NMD.operands())
2026       Record.push_back(VE.getMetadataID(N));
2027     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
2028     Record.clear();
2029   }
2030 }
2031 
2032 unsigned ModuleBitcodeWriter::createMetadataStringsAbbrev() {
2033   auto Abbv = std::make_shared<BitCodeAbbrev>();
2034   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRINGS));
2035   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // # of strings
2036   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // offset to chars
2037   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
2038   return Stream.EmitAbbrev(std::move(Abbv));
2039 }
2040 
2041 /// Write out a record for MDString.
2042 ///
2043 /// All the metadata strings in a metadata block are emitted in a single
2044 /// record.  The sizes and strings themselves are shoved into a blob.
2045 void ModuleBitcodeWriter::writeMetadataStrings(
2046     ArrayRef<const Metadata *> Strings, SmallVectorImpl<uint64_t> &Record) {
2047   if (Strings.empty())
2048     return;
2049 
2050   // Start the record with the number of strings.
2051   Record.push_back(bitc::METADATA_STRINGS);
2052   Record.push_back(Strings.size());
2053 
2054   // Emit the sizes of the strings in the blob.
2055   SmallString<256> Blob;
2056   {
2057     BitstreamWriter W(Blob);
2058     for (const Metadata *MD : Strings)
2059       W.EmitVBR(cast<MDString>(MD)->getLength(), 6);
2060     W.FlushToWord();
2061   }
2062 
2063   // Add the offset to the strings to the record.
2064   Record.push_back(Blob.size());
2065 
2066   // Add the strings to the blob.
2067   for (const Metadata *MD : Strings)
2068     Blob.append(cast<MDString>(MD)->getString());
2069 
2070   // Emit the final record.
2071   Stream.EmitRecordWithBlob(createMetadataStringsAbbrev(), Record, Blob);
2072   Record.clear();
2073 }
2074 
2075 // Generates an enum to use as an index in the Abbrev array of Metadata record.
2076 enum MetadataAbbrev : unsigned {
2077 #define HANDLE_MDNODE_LEAF(CLASS) CLASS##AbbrevID,
2078 #include "llvm/IR/Metadata.def"
2079   LastPlusOne
2080 };
2081 
2082 void ModuleBitcodeWriter::writeMetadataRecords(
2083     ArrayRef<const Metadata *> MDs, SmallVectorImpl<uint64_t> &Record,
2084     std::vector<unsigned> *MDAbbrevs, std::vector<uint64_t> *IndexPos) {
2085   if (MDs.empty())
2086     return;
2087 
2088   // Initialize MDNode abbreviations.
2089 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
2090 #include "llvm/IR/Metadata.def"
2091 
2092   for (const Metadata *MD : MDs) {
2093     if (IndexPos)
2094       IndexPos->push_back(Stream.GetCurrentBitNo());
2095     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
2096       assert(N->isResolved() && "Expected forward references to be resolved");
2097 
2098       switch (N->getMetadataID()) {
2099       default:
2100         llvm_unreachable("Invalid MDNode subclass");
2101 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
2102   case Metadata::CLASS##Kind:                                                  \
2103     if (MDAbbrevs)                                                             \
2104       write##CLASS(cast<CLASS>(N), Record,                                     \
2105                    (*MDAbbrevs)[MetadataAbbrev::CLASS##AbbrevID]);             \
2106     else                                                                       \
2107       write##CLASS(cast<CLASS>(N), Record, CLASS##Abbrev);                     \
2108     continue;
2109 #include "llvm/IR/Metadata.def"
2110       }
2111     }
2112     writeValueAsMetadata(cast<ValueAsMetadata>(MD), Record);
2113   }
2114 }
2115 
2116 void ModuleBitcodeWriter::writeModuleMetadata() {
2117   if (!VE.hasMDs() && M.named_metadata_empty())
2118     return;
2119 
2120   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 4);
2121   SmallVector<uint64_t, 64> Record;
2122 
2123   // Emit all abbrevs upfront, so that the reader can jump in the middle of the
2124   // block and load any metadata.
2125   std::vector<unsigned> MDAbbrevs;
2126 
2127   MDAbbrevs.resize(MetadataAbbrev::LastPlusOne);
2128   MDAbbrevs[MetadataAbbrev::DILocationAbbrevID] = createDILocationAbbrev();
2129   MDAbbrevs[MetadataAbbrev::GenericDINodeAbbrevID] =
2130       createGenericDINodeAbbrev();
2131 
2132   auto Abbv = std::make_shared<BitCodeAbbrev>();
2133   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX_OFFSET));
2134   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2135   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2136   unsigned OffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2137 
2138   Abbv = std::make_shared<BitCodeAbbrev>();
2139   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX));
2140   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2141   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2142   unsigned IndexAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2143 
2144   // Emit MDStrings together upfront.
2145   writeMetadataStrings(VE.getMDStrings(), Record);
2146 
2147   // We only emit an index for the metadata record if we have more than a given
2148   // (naive) threshold of metadatas, otherwise it is not worth it.
2149   if (VE.getNonMDStrings().size() > IndexThreshold) {
2150     // Write a placeholder value in for the offset of the metadata index,
2151     // which is written after the records, so that it can include
2152     // the offset of each entry. The placeholder offset will be
2153     // updated after all records are emitted.
2154     uint64_t Vals[] = {0, 0};
2155     Stream.EmitRecord(bitc::METADATA_INDEX_OFFSET, Vals, OffsetAbbrev);
2156   }
2157 
2158   // Compute and save the bit offset to the current position, which will be
2159   // patched when we emit the index later. We can simply subtract the 64-bit
2160   // fixed size from the current bit number to get the location to backpatch.
2161   uint64_t IndexOffsetRecordBitPos = Stream.GetCurrentBitNo();
2162 
2163   // This index will contain the bitpos for each individual record.
2164   std::vector<uint64_t> IndexPos;
2165   IndexPos.reserve(VE.getNonMDStrings().size());
2166 
2167   // Write all the records
2168   writeMetadataRecords(VE.getNonMDStrings(), Record, &MDAbbrevs, &IndexPos);
2169 
2170   if (VE.getNonMDStrings().size() > IndexThreshold) {
2171     // Now that we have emitted all the records we will emit the index. But
2172     // first
2173     // backpatch the forward reference so that the reader can skip the records
2174     // efficiently.
2175     Stream.BackpatchWord64(IndexOffsetRecordBitPos - 64,
2176                            Stream.GetCurrentBitNo() - IndexOffsetRecordBitPos);
2177 
2178     // Delta encode the index.
2179     uint64_t PreviousValue = IndexOffsetRecordBitPos;
2180     for (auto &Elt : IndexPos) {
2181       auto EltDelta = Elt - PreviousValue;
2182       PreviousValue = Elt;
2183       Elt = EltDelta;
2184     }
2185     // Emit the index record.
2186     Stream.EmitRecord(bitc::METADATA_INDEX, IndexPos, IndexAbbrev);
2187     IndexPos.clear();
2188   }
2189 
2190   // Write the named metadata now.
2191   writeNamedMetadata(Record);
2192 
2193   auto AddDeclAttachedMetadata = [&](const GlobalObject &GO) {
2194     SmallVector<uint64_t, 4> Record;
2195     Record.push_back(VE.getValueID(&GO));
2196     pushGlobalMetadataAttachment(Record, GO);
2197     Stream.EmitRecord(bitc::METADATA_GLOBAL_DECL_ATTACHMENT, Record);
2198   };
2199   for (const Function &F : M)
2200     if (F.isDeclaration() && F.hasMetadata())
2201       AddDeclAttachedMetadata(F);
2202   // FIXME: Only store metadata for declarations here, and move data for global
2203   // variable definitions to a separate block (PR28134).
2204   for (const GlobalVariable &GV : M.globals())
2205     if (GV.hasMetadata())
2206       AddDeclAttachedMetadata(GV);
2207 
2208   Stream.ExitBlock();
2209 }
2210 
2211 void ModuleBitcodeWriter::writeFunctionMetadata(const Function &F) {
2212   if (!VE.hasMDs())
2213     return;
2214 
2215   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
2216   SmallVector<uint64_t, 64> Record;
2217   writeMetadataStrings(VE.getMDStrings(), Record);
2218   writeMetadataRecords(VE.getNonMDStrings(), Record);
2219   Stream.ExitBlock();
2220 }
2221 
2222 void ModuleBitcodeWriter::pushGlobalMetadataAttachment(
2223     SmallVectorImpl<uint64_t> &Record, const GlobalObject &GO) {
2224   // [n x [id, mdnode]]
2225   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2226   GO.getAllMetadata(MDs);
2227   for (const auto &I : MDs) {
2228     Record.push_back(I.first);
2229     Record.push_back(VE.getMetadataID(I.second));
2230   }
2231 }
2232 
2233 void ModuleBitcodeWriter::writeFunctionMetadataAttachment(const Function &F) {
2234   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
2235 
2236   SmallVector<uint64_t, 64> Record;
2237 
2238   if (F.hasMetadata()) {
2239     pushGlobalMetadataAttachment(Record, F);
2240     Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2241     Record.clear();
2242   }
2243 
2244   // Write metadata attachments
2245   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
2246   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2247   for (const BasicBlock &BB : F)
2248     for (const Instruction &I : BB) {
2249       MDs.clear();
2250       I.getAllMetadataOtherThanDebugLoc(MDs);
2251 
2252       // If no metadata, ignore instruction.
2253       if (MDs.empty()) continue;
2254 
2255       Record.push_back(VE.getInstructionID(&I));
2256 
2257       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
2258         Record.push_back(MDs[i].first);
2259         Record.push_back(VE.getMetadataID(MDs[i].second));
2260       }
2261       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2262       Record.clear();
2263     }
2264 
2265   Stream.ExitBlock();
2266 }
2267 
2268 void ModuleBitcodeWriter::writeModuleMetadataKinds() {
2269   SmallVector<uint64_t, 64> Record;
2270 
2271   // Write metadata kinds
2272   // METADATA_KIND - [n x [id, name]]
2273   SmallVector<StringRef, 8> Names;
2274   M.getMDKindNames(Names);
2275 
2276   if (Names.empty()) return;
2277 
2278   Stream.EnterSubblock(bitc::METADATA_KIND_BLOCK_ID, 3);
2279 
2280   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
2281     Record.push_back(MDKindID);
2282     StringRef KName = Names[MDKindID];
2283     Record.append(KName.begin(), KName.end());
2284 
2285     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
2286     Record.clear();
2287   }
2288 
2289   Stream.ExitBlock();
2290 }
2291 
2292 void ModuleBitcodeWriter::writeOperandBundleTags() {
2293   // Write metadata kinds
2294   //
2295   // OPERAND_BUNDLE_TAGS_BLOCK_ID : N x OPERAND_BUNDLE_TAG
2296   //
2297   // OPERAND_BUNDLE_TAG - [strchr x N]
2298 
2299   SmallVector<StringRef, 8> Tags;
2300   M.getOperandBundleTags(Tags);
2301 
2302   if (Tags.empty())
2303     return;
2304 
2305   Stream.EnterSubblock(bitc::OPERAND_BUNDLE_TAGS_BLOCK_ID, 3);
2306 
2307   SmallVector<uint64_t, 64> Record;
2308 
2309   for (auto Tag : Tags) {
2310     Record.append(Tag.begin(), Tag.end());
2311 
2312     Stream.EmitRecord(bitc::OPERAND_BUNDLE_TAG, Record, 0);
2313     Record.clear();
2314   }
2315 
2316   Stream.ExitBlock();
2317 }
2318 
2319 void ModuleBitcodeWriter::writeSyncScopeNames() {
2320   SmallVector<StringRef, 8> SSNs;
2321   M.getContext().getSyncScopeNames(SSNs);
2322   if (SSNs.empty())
2323     return;
2324 
2325   Stream.EnterSubblock(bitc::SYNC_SCOPE_NAMES_BLOCK_ID, 2);
2326 
2327   SmallVector<uint64_t, 64> Record;
2328   for (auto SSN : SSNs) {
2329     Record.append(SSN.begin(), SSN.end());
2330     Stream.EmitRecord(bitc::SYNC_SCOPE_NAME, Record, 0);
2331     Record.clear();
2332   }
2333 
2334   Stream.ExitBlock();
2335 }
2336 
2337 void ModuleBitcodeWriter::writeConstants(unsigned FirstVal, unsigned LastVal,
2338                                          bool isGlobal) {
2339   if (FirstVal == LastVal) return;
2340 
2341   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
2342 
2343   unsigned AggregateAbbrev = 0;
2344   unsigned String8Abbrev = 0;
2345   unsigned CString7Abbrev = 0;
2346   unsigned CString6Abbrev = 0;
2347   // If this is a constant pool for the module, emit module-specific abbrevs.
2348   if (isGlobal) {
2349     // Abbrev for CST_CODE_AGGREGATE.
2350     auto Abbv = std::make_shared<BitCodeAbbrev>();
2351     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
2352     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2353     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
2354     AggregateAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2355 
2356     // Abbrev for CST_CODE_STRING.
2357     Abbv = std::make_shared<BitCodeAbbrev>();
2358     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
2359     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2360     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2361     String8Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2362     // Abbrev for CST_CODE_CSTRING.
2363     Abbv = std::make_shared<BitCodeAbbrev>();
2364     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2365     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2366     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2367     CString7Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2368     // Abbrev for CST_CODE_CSTRING.
2369     Abbv = std::make_shared<BitCodeAbbrev>();
2370     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2371     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2372     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2373     CString6Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2374   }
2375 
2376   SmallVector<uint64_t, 64> Record;
2377 
2378   const ValueEnumerator::ValueList &Vals = VE.getValues();
2379   Type *LastTy = nullptr;
2380   for (unsigned i = FirstVal; i != LastVal; ++i) {
2381     const Value *V = Vals[i].first;
2382     // If we need to switch types, do so now.
2383     if (V->getType() != LastTy) {
2384       LastTy = V->getType();
2385       Record.push_back(VE.getTypeID(LastTy));
2386       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
2387                         CONSTANTS_SETTYPE_ABBREV);
2388       Record.clear();
2389     }
2390 
2391     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
2392       Record.push_back(unsigned(IA->hasSideEffects()) |
2393                        unsigned(IA->isAlignStack()) << 1 |
2394                        unsigned(IA->getDialect()&1) << 2);
2395 
2396       // Add the asm string.
2397       const std::string &AsmStr = IA->getAsmString();
2398       Record.push_back(AsmStr.size());
2399       Record.append(AsmStr.begin(), AsmStr.end());
2400 
2401       // Add the constraint string.
2402       const std::string &ConstraintStr = IA->getConstraintString();
2403       Record.push_back(ConstraintStr.size());
2404       Record.append(ConstraintStr.begin(), ConstraintStr.end());
2405       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
2406       Record.clear();
2407       continue;
2408     }
2409     const Constant *C = cast<Constant>(V);
2410     unsigned Code = -1U;
2411     unsigned AbbrevToUse = 0;
2412     if (C->isNullValue()) {
2413       Code = bitc::CST_CODE_NULL;
2414     } else if (isa<UndefValue>(C)) {
2415       Code = bitc::CST_CODE_UNDEF;
2416     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
2417       if (IV->getBitWidth() <= 64) {
2418         uint64_t V = IV->getSExtValue();
2419         emitSignedInt64(Record, V);
2420         Code = bitc::CST_CODE_INTEGER;
2421         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
2422       } else {                             // Wide integers, > 64 bits in size.
2423         emitWideAPInt(Record, IV->getValue());
2424         Code = bitc::CST_CODE_WIDE_INTEGER;
2425       }
2426     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
2427       Code = bitc::CST_CODE_FLOAT;
2428       Type *Ty = CFP->getType();
2429       if (Ty->isHalfTy() || Ty->isBFloatTy() || Ty->isFloatTy() ||
2430           Ty->isDoubleTy()) {
2431         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
2432       } else if (Ty->isX86_FP80Ty()) {
2433         // api needed to prevent premature destruction
2434         // bits are not in the same order as a normal i80 APInt, compensate.
2435         APInt api = CFP->getValueAPF().bitcastToAPInt();
2436         const uint64_t *p = api.getRawData();
2437         Record.push_back((p[1] << 48) | (p[0] >> 16));
2438         Record.push_back(p[0] & 0xffffLL);
2439       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
2440         APInt api = CFP->getValueAPF().bitcastToAPInt();
2441         const uint64_t *p = api.getRawData();
2442         Record.push_back(p[0]);
2443         Record.push_back(p[1]);
2444       } else {
2445         assert(0 && "Unknown FP type!");
2446       }
2447     } else if (isa<ConstantDataSequential>(C) &&
2448                cast<ConstantDataSequential>(C)->isString()) {
2449       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
2450       // Emit constant strings specially.
2451       unsigned NumElts = Str->getNumElements();
2452       // If this is a null-terminated string, use the denser CSTRING encoding.
2453       if (Str->isCString()) {
2454         Code = bitc::CST_CODE_CSTRING;
2455         --NumElts;  // Don't encode the null, which isn't allowed by char6.
2456       } else {
2457         Code = bitc::CST_CODE_STRING;
2458         AbbrevToUse = String8Abbrev;
2459       }
2460       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
2461       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
2462       for (unsigned i = 0; i != NumElts; ++i) {
2463         unsigned char V = Str->getElementAsInteger(i);
2464         Record.push_back(V);
2465         isCStr7 &= (V & 128) == 0;
2466         if (isCStrChar6)
2467           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
2468       }
2469 
2470       if (isCStrChar6)
2471         AbbrevToUse = CString6Abbrev;
2472       else if (isCStr7)
2473         AbbrevToUse = CString7Abbrev;
2474     } else if (const ConstantDataSequential *CDS =
2475                   dyn_cast<ConstantDataSequential>(C)) {
2476       Code = bitc::CST_CODE_DATA;
2477       Type *EltTy = CDS->getElementType();
2478       if (isa<IntegerType>(EltTy)) {
2479         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2480           Record.push_back(CDS->getElementAsInteger(i));
2481       } else {
2482         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2483           Record.push_back(
2484               CDS->getElementAsAPFloat(i).bitcastToAPInt().getLimitedValue());
2485       }
2486     } else if (isa<ConstantAggregate>(C)) {
2487       Code = bitc::CST_CODE_AGGREGATE;
2488       for (const Value *Op : C->operands())
2489         Record.push_back(VE.getValueID(Op));
2490       AbbrevToUse = AggregateAbbrev;
2491     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
2492       switch (CE->getOpcode()) {
2493       default:
2494         if (Instruction::isCast(CE->getOpcode())) {
2495           Code = bitc::CST_CODE_CE_CAST;
2496           Record.push_back(getEncodedCastOpcode(CE->getOpcode()));
2497           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2498           Record.push_back(VE.getValueID(C->getOperand(0)));
2499           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
2500         } else {
2501           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
2502           Code = bitc::CST_CODE_CE_BINOP;
2503           Record.push_back(getEncodedBinaryOpcode(CE->getOpcode()));
2504           Record.push_back(VE.getValueID(C->getOperand(0)));
2505           Record.push_back(VE.getValueID(C->getOperand(1)));
2506           uint64_t Flags = getOptimizationFlags(CE);
2507           if (Flags != 0)
2508             Record.push_back(Flags);
2509         }
2510         break;
2511       case Instruction::FNeg: {
2512         assert(CE->getNumOperands() == 1 && "Unknown constant expr!");
2513         Code = bitc::CST_CODE_CE_UNOP;
2514         Record.push_back(getEncodedUnaryOpcode(CE->getOpcode()));
2515         Record.push_back(VE.getValueID(C->getOperand(0)));
2516         uint64_t Flags = getOptimizationFlags(CE);
2517         if (Flags != 0)
2518           Record.push_back(Flags);
2519         break;
2520       }
2521       case Instruction::GetElementPtr: {
2522         Code = bitc::CST_CODE_CE_GEP;
2523         const auto *GO = cast<GEPOperator>(C);
2524         Record.push_back(VE.getTypeID(GO->getSourceElementType()));
2525         if (Optional<unsigned> Idx = GO->getInRangeIndex()) {
2526           Code = bitc::CST_CODE_CE_GEP_WITH_INRANGE_INDEX;
2527           Record.push_back((*Idx << 1) | GO->isInBounds());
2528         } else if (GO->isInBounds())
2529           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
2530         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
2531           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
2532           Record.push_back(VE.getValueID(C->getOperand(i)));
2533         }
2534         break;
2535       }
2536       case Instruction::Select:
2537         Code = bitc::CST_CODE_CE_SELECT;
2538         Record.push_back(VE.getValueID(C->getOperand(0)));
2539         Record.push_back(VE.getValueID(C->getOperand(1)));
2540         Record.push_back(VE.getValueID(C->getOperand(2)));
2541         break;
2542       case Instruction::ExtractElement:
2543         Code = bitc::CST_CODE_CE_EXTRACTELT;
2544         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2545         Record.push_back(VE.getValueID(C->getOperand(0)));
2546         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
2547         Record.push_back(VE.getValueID(C->getOperand(1)));
2548         break;
2549       case Instruction::InsertElement:
2550         Code = bitc::CST_CODE_CE_INSERTELT;
2551         Record.push_back(VE.getValueID(C->getOperand(0)));
2552         Record.push_back(VE.getValueID(C->getOperand(1)));
2553         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
2554         Record.push_back(VE.getValueID(C->getOperand(2)));
2555         break;
2556       case Instruction::ShuffleVector:
2557         // If the return type and argument types are the same, this is a
2558         // standard shufflevector instruction.  If the types are different,
2559         // then the shuffle is widening or truncating the input vectors, and
2560         // the argument type must also be encoded.
2561         if (C->getType() == C->getOperand(0)->getType()) {
2562           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
2563         } else {
2564           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
2565           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2566         }
2567         Record.push_back(VE.getValueID(C->getOperand(0)));
2568         Record.push_back(VE.getValueID(C->getOperand(1)));
2569         Record.push_back(VE.getValueID(CE->getShuffleMaskForBitcode()));
2570         break;
2571       case Instruction::ICmp:
2572       case Instruction::FCmp:
2573         Code = bitc::CST_CODE_CE_CMP;
2574         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2575         Record.push_back(VE.getValueID(C->getOperand(0)));
2576         Record.push_back(VE.getValueID(C->getOperand(1)));
2577         Record.push_back(CE->getPredicate());
2578         break;
2579       }
2580     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
2581       Code = bitc::CST_CODE_BLOCKADDRESS;
2582       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
2583       Record.push_back(VE.getValueID(BA->getFunction()));
2584       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
2585     } else {
2586 #ifndef NDEBUG
2587       C->dump();
2588 #endif
2589       llvm_unreachable("Unknown constant!");
2590     }
2591     Stream.EmitRecord(Code, Record, AbbrevToUse);
2592     Record.clear();
2593   }
2594 
2595   Stream.ExitBlock();
2596 }
2597 
2598 void ModuleBitcodeWriter::writeModuleConstants() {
2599   const ValueEnumerator::ValueList &Vals = VE.getValues();
2600 
2601   // Find the first constant to emit, which is the first non-globalvalue value.
2602   // We know globalvalues have been emitted by WriteModuleInfo.
2603   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
2604     if (!isa<GlobalValue>(Vals[i].first)) {
2605       writeConstants(i, Vals.size(), true);
2606       return;
2607     }
2608   }
2609 }
2610 
2611 /// pushValueAndType - The file has to encode both the value and type id for
2612 /// many values, because we need to know what type to create for forward
2613 /// references.  However, most operands are not forward references, so this type
2614 /// field is not needed.
2615 ///
2616 /// This function adds V's value ID to Vals.  If the value ID is higher than the
2617 /// instruction ID, then it is a forward reference, and it also includes the
2618 /// type ID.  The value ID that is written is encoded relative to the InstID.
2619 bool ModuleBitcodeWriter::pushValueAndType(const Value *V, unsigned InstID,
2620                                            SmallVectorImpl<unsigned> &Vals) {
2621   unsigned ValID = VE.getValueID(V);
2622   // Make encoding relative to the InstID.
2623   Vals.push_back(InstID - ValID);
2624   if (ValID >= InstID) {
2625     Vals.push_back(VE.getTypeID(V->getType()));
2626     return true;
2627   }
2628   return false;
2629 }
2630 
2631 void ModuleBitcodeWriter::writeOperandBundles(const CallBase &CS,
2632                                               unsigned InstID) {
2633   SmallVector<unsigned, 64> Record;
2634   LLVMContext &C = CS.getContext();
2635 
2636   for (unsigned i = 0, e = CS.getNumOperandBundles(); i != e; ++i) {
2637     const auto &Bundle = CS.getOperandBundleAt(i);
2638     Record.push_back(C.getOperandBundleTagID(Bundle.getTagName()));
2639 
2640     for (auto &Input : Bundle.Inputs)
2641       pushValueAndType(Input, InstID, Record);
2642 
2643     Stream.EmitRecord(bitc::FUNC_CODE_OPERAND_BUNDLE, Record);
2644     Record.clear();
2645   }
2646 }
2647 
2648 /// pushValue - Like pushValueAndType, but where the type of the value is
2649 /// omitted (perhaps it was already encoded in an earlier operand).
2650 void ModuleBitcodeWriter::pushValue(const Value *V, unsigned InstID,
2651                                     SmallVectorImpl<unsigned> &Vals) {
2652   unsigned ValID = VE.getValueID(V);
2653   Vals.push_back(InstID - ValID);
2654 }
2655 
2656 void ModuleBitcodeWriter::pushValueSigned(const Value *V, unsigned InstID,
2657                                           SmallVectorImpl<uint64_t> &Vals) {
2658   unsigned ValID = VE.getValueID(V);
2659   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
2660   emitSignedInt64(Vals, diff);
2661 }
2662 
2663 /// WriteInstruction - Emit an instruction to the specified stream.
2664 void ModuleBitcodeWriter::writeInstruction(const Instruction &I,
2665                                            unsigned InstID,
2666                                            SmallVectorImpl<unsigned> &Vals) {
2667   unsigned Code = 0;
2668   unsigned AbbrevToUse = 0;
2669   VE.setInstructionID(&I);
2670   switch (I.getOpcode()) {
2671   default:
2672     if (Instruction::isCast(I.getOpcode())) {
2673       Code = bitc::FUNC_CODE_INST_CAST;
2674       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2675         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
2676       Vals.push_back(VE.getTypeID(I.getType()));
2677       Vals.push_back(getEncodedCastOpcode(I.getOpcode()));
2678     } else {
2679       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
2680       Code = bitc::FUNC_CODE_INST_BINOP;
2681       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2682         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
2683       pushValue(I.getOperand(1), InstID, Vals);
2684       Vals.push_back(getEncodedBinaryOpcode(I.getOpcode()));
2685       uint64_t Flags = getOptimizationFlags(&I);
2686       if (Flags != 0) {
2687         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
2688           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
2689         Vals.push_back(Flags);
2690       }
2691     }
2692     break;
2693   case Instruction::FNeg: {
2694     Code = bitc::FUNC_CODE_INST_UNOP;
2695     if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2696       AbbrevToUse = FUNCTION_INST_UNOP_ABBREV;
2697     Vals.push_back(getEncodedUnaryOpcode(I.getOpcode()));
2698     uint64_t Flags = getOptimizationFlags(&I);
2699     if (Flags != 0) {
2700       if (AbbrevToUse == FUNCTION_INST_UNOP_ABBREV)
2701         AbbrevToUse = FUNCTION_INST_UNOP_FLAGS_ABBREV;
2702       Vals.push_back(Flags);
2703     }
2704     break;
2705   }
2706   case Instruction::GetElementPtr: {
2707     Code = bitc::FUNC_CODE_INST_GEP;
2708     AbbrevToUse = FUNCTION_INST_GEP_ABBREV;
2709     auto &GEPInst = cast<GetElementPtrInst>(I);
2710     Vals.push_back(GEPInst.isInBounds());
2711     Vals.push_back(VE.getTypeID(GEPInst.getSourceElementType()));
2712     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
2713       pushValueAndType(I.getOperand(i), InstID, Vals);
2714     break;
2715   }
2716   case Instruction::ExtractValue: {
2717     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
2718     pushValueAndType(I.getOperand(0), InstID, Vals);
2719     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
2720     Vals.append(EVI->idx_begin(), EVI->idx_end());
2721     break;
2722   }
2723   case Instruction::InsertValue: {
2724     Code = bitc::FUNC_CODE_INST_INSERTVAL;
2725     pushValueAndType(I.getOperand(0), InstID, Vals);
2726     pushValueAndType(I.getOperand(1), InstID, Vals);
2727     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
2728     Vals.append(IVI->idx_begin(), IVI->idx_end());
2729     break;
2730   }
2731   case Instruction::Select: {
2732     Code = bitc::FUNC_CODE_INST_VSELECT;
2733     pushValueAndType(I.getOperand(1), InstID, Vals);
2734     pushValue(I.getOperand(2), InstID, Vals);
2735     pushValueAndType(I.getOperand(0), InstID, Vals);
2736     uint64_t Flags = getOptimizationFlags(&I);
2737     if (Flags != 0)
2738       Vals.push_back(Flags);
2739     break;
2740   }
2741   case Instruction::ExtractElement:
2742     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
2743     pushValueAndType(I.getOperand(0), InstID, Vals);
2744     pushValueAndType(I.getOperand(1), InstID, Vals);
2745     break;
2746   case Instruction::InsertElement:
2747     Code = bitc::FUNC_CODE_INST_INSERTELT;
2748     pushValueAndType(I.getOperand(0), InstID, Vals);
2749     pushValue(I.getOperand(1), InstID, Vals);
2750     pushValueAndType(I.getOperand(2), InstID, Vals);
2751     break;
2752   case Instruction::ShuffleVector:
2753     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
2754     pushValueAndType(I.getOperand(0), InstID, Vals);
2755     pushValue(I.getOperand(1), InstID, Vals);
2756     pushValue(cast<ShuffleVectorInst>(I).getShuffleMaskForBitcode(), InstID,
2757               Vals);
2758     break;
2759   case Instruction::ICmp:
2760   case Instruction::FCmp: {
2761     // compare returning Int1Ty or vector of Int1Ty
2762     Code = bitc::FUNC_CODE_INST_CMP2;
2763     pushValueAndType(I.getOperand(0), InstID, Vals);
2764     pushValue(I.getOperand(1), InstID, Vals);
2765     Vals.push_back(cast<CmpInst>(I).getPredicate());
2766     uint64_t Flags = getOptimizationFlags(&I);
2767     if (Flags != 0)
2768       Vals.push_back(Flags);
2769     break;
2770   }
2771 
2772   case Instruction::Ret:
2773     {
2774       Code = bitc::FUNC_CODE_INST_RET;
2775       unsigned NumOperands = I.getNumOperands();
2776       if (NumOperands == 0)
2777         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
2778       else if (NumOperands == 1) {
2779         if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2780           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
2781       } else {
2782         for (unsigned i = 0, e = NumOperands; i != e; ++i)
2783           pushValueAndType(I.getOperand(i), InstID, Vals);
2784       }
2785     }
2786     break;
2787   case Instruction::Br:
2788     {
2789       Code = bitc::FUNC_CODE_INST_BR;
2790       const BranchInst &II = cast<BranchInst>(I);
2791       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
2792       if (II.isConditional()) {
2793         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
2794         pushValue(II.getCondition(), InstID, Vals);
2795       }
2796     }
2797     break;
2798   case Instruction::Switch:
2799     {
2800       Code = bitc::FUNC_CODE_INST_SWITCH;
2801       const SwitchInst &SI = cast<SwitchInst>(I);
2802       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
2803       pushValue(SI.getCondition(), InstID, Vals);
2804       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
2805       for (auto Case : SI.cases()) {
2806         Vals.push_back(VE.getValueID(Case.getCaseValue()));
2807         Vals.push_back(VE.getValueID(Case.getCaseSuccessor()));
2808       }
2809     }
2810     break;
2811   case Instruction::IndirectBr:
2812     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
2813     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2814     // Encode the address operand as relative, but not the basic blocks.
2815     pushValue(I.getOperand(0), InstID, Vals);
2816     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
2817       Vals.push_back(VE.getValueID(I.getOperand(i)));
2818     break;
2819 
2820   case Instruction::Invoke: {
2821     const InvokeInst *II = cast<InvokeInst>(&I);
2822     const Value *Callee = II->getCalledOperand();
2823     FunctionType *FTy = II->getFunctionType();
2824 
2825     if (II->hasOperandBundles())
2826       writeOperandBundles(*II, InstID);
2827 
2828     Code = bitc::FUNC_CODE_INST_INVOKE;
2829 
2830     Vals.push_back(VE.getAttributeListID(II->getAttributes()));
2831     Vals.push_back(II->getCallingConv() | 1 << 13);
2832     Vals.push_back(VE.getValueID(II->getNormalDest()));
2833     Vals.push_back(VE.getValueID(II->getUnwindDest()));
2834     Vals.push_back(VE.getTypeID(FTy));
2835     pushValueAndType(Callee, InstID, Vals);
2836 
2837     // Emit value #'s for the fixed parameters.
2838     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
2839       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
2840 
2841     // Emit type/value pairs for varargs params.
2842     if (FTy->isVarArg()) {
2843       for (unsigned i = FTy->getNumParams(), e = II->getNumArgOperands();
2844            i != e; ++i)
2845         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
2846     }
2847     break;
2848   }
2849   case Instruction::Resume:
2850     Code = bitc::FUNC_CODE_INST_RESUME;
2851     pushValueAndType(I.getOperand(0), InstID, Vals);
2852     break;
2853   case Instruction::CleanupRet: {
2854     Code = bitc::FUNC_CODE_INST_CLEANUPRET;
2855     const auto &CRI = cast<CleanupReturnInst>(I);
2856     pushValue(CRI.getCleanupPad(), InstID, Vals);
2857     if (CRI.hasUnwindDest())
2858       Vals.push_back(VE.getValueID(CRI.getUnwindDest()));
2859     break;
2860   }
2861   case Instruction::CatchRet: {
2862     Code = bitc::FUNC_CODE_INST_CATCHRET;
2863     const auto &CRI = cast<CatchReturnInst>(I);
2864     pushValue(CRI.getCatchPad(), InstID, Vals);
2865     Vals.push_back(VE.getValueID(CRI.getSuccessor()));
2866     break;
2867   }
2868   case Instruction::CleanupPad:
2869   case Instruction::CatchPad: {
2870     const auto &FuncletPad = cast<FuncletPadInst>(I);
2871     Code = isa<CatchPadInst>(FuncletPad) ? bitc::FUNC_CODE_INST_CATCHPAD
2872                                          : bitc::FUNC_CODE_INST_CLEANUPPAD;
2873     pushValue(FuncletPad.getParentPad(), InstID, Vals);
2874 
2875     unsigned NumArgOperands = FuncletPad.getNumArgOperands();
2876     Vals.push_back(NumArgOperands);
2877     for (unsigned Op = 0; Op != NumArgOperands; ++Op)
2878       pushValueAndType(FuncletPad.getArgOperand(Op), InstID, Vals);
2879     break;
2880   }
2881   case Instruction::CatchSwitch: {
2882     Code = bitc::FUNC_CODE_INST_CATCHSWITCH;
2883     const auto &CatchSwitch = cast<CatchSwitchInst>(I);
2884 
2885     pushValue(CatchSwitch.getParentPad(), InstID, Vals);
2886 
2887     unsigned NumHandlers = CatchSwitch.getNumHandlers();
2888     Vals.push_back(NumHandlers);
2889     for (const BasicBlock *CatchPadBB : CatchSwitch.handlers())
2890       Vals.push_back(VE.getValueID(CatchPadBB));
2891 
2892     if (CatchSwitch.hasUnwindDest())
2893       Vals.push_back(VE.getValueID(CatchSwitch.getUnwindDest()));
2894     break;
2895   }
2896   case Instruction::CallBr: {
2897     const CallBrInst *CBI = cast<CallBrInst>(&I);
2898     const Value *Callee = CBI->getCalledOperand();
2899     FunctionType *FTy = CBI->getFunctionType();
2900 
2901     if (CBI->hasOperandBundles())
2902       writeOperandBundles(*CBI, InstID);
2903 
2904     Code = bitc::FUNC_CODE_INST_CALLBR;
2905 
2906     Vals.push_back(VE.getAttributeListID(CBI->getAttributes()));
2907 
2908     Vals.push_back(CBI->getCallingConv() << bitc::CALL_CCONV |
2909                    1 << bitc::CALL_EXPLICIT_TYPE);
2910 
2911     Vals.push_back(VE.getValueID(CBI->getDefaultDest()));
2912     Vals.push_back(CBI->getNumIndirectDests());
2913     for (unsigned i = 0, e = CBI->getNumIndirectDests(); i != e; ++i)
2914       Vals.push_back(VE.getValueID(CBI->getIndirectDest(i)));
2915 
2916     Vals.push_back(VE.getTypeID(FTy));
2917     pushValueAndType(Callee, InstID, Vals);
2918 
2919     // Emit value #'s for the fixed parameters.
2920     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
2921       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
2922 
2923     // Emit type/value pairs for varargs params.
2924     if (FTy->isVarArg()) {
2925       for (unsigned i = FTy->getNumParams(), e = CBI->getNumArgOperands();
2926            i != e; ++i)
2927         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
2928     }
2929     break;
2930   }
2931   case Instruction::Unreachable:
2932     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
2933     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
2934     break;
2935 
2936   case Instruction::PHI: {
2937     const PHINode &PN = cast<PHINode>(I);
2938     Code = bitc::FUNC_CODE_INST_PHI;
2939     // With the newer instruction encoding, forward references could give
2940     // negative valued IDs.  This is most common for PHIs, so we use
2941     // signed VBRs.
2942     SmallVector<uint64_t, 128> Vals64;
2943     Vals64.push_back(VE.getTypeID(PN.getType()));
2944     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
2945       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64);
2946       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
2947     }
2948 
2949     uint64_t Flags = getOptimizationFlags(&I);
2950     if (Flags != 0)
2951       Vals64.push_back(Flags);
2952 
2953     // Emit a Vals64 vector and exit.
2954     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
2955     Vals64.clear();
2956     return;
2957   }
2958 
2959   case Instruction::LandingPad: {
2960     const LandingPadInst &LP = cast<LandingPadInst>(I);
2961     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
2962     Vals.push_back(VE.getTypeID(LP.getType()));
2963     Vals.push_back(LP.isCleanup());
2964     Vals.push_back(LP.getNumClauses());
2965     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
2966       if (LP.isCatch(I))
2967         Vals.push_back(LandingPadInst::Catch);
2968       else
2969         Vals.push_back(LandingPadInst::Filter);
2970       pushValueAndType(LP.getClause(I), InstID, Vals);
2971     }
2972     break;
2973   }
2974 
2975   case Instruction::Alloca: {
2976     Code = bitc::FUNC_CODE_INST_ALLOCA;
2977     const AllocaInst &AI = cast<AllocaInst>(I);
2978     Vals.push_back(VE.getTypeID(AI.getAllocatedType()));
2979     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2980     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
2981     using APV = AllocaPackedValues;
2982     unsigned Record = 0;
2983     Bitfield::set<APV::Align>(Record, getEncodedAlign(AI.getAlign()));
2984     Bitfield::set<APV::UsedWithInAlloca>(Record, AI.isUsedWithInAlloca());
2985     Bitfield::set<APV::ExplicitType>(Record, true);
2986     Bitfield::set<APV::SwiftError>(Record, AI.isSwiftError());
2987     Vals.push_back(Record);
2988     break;
2989   }
2990 
2991   case Instruction::Load:
2992     if (cast<LoadInst>(I).isAtomic()) {
2993       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
2994       pushValueAndType(I.getOperand(0), InstID, Vals);
2995     } else {
2996       Code = bitc::FUNC_CODE_INST_LOAD;
2997       if (!pushValueAndType(I.getOperand(0), InstID, Vals)) // ptr
2998         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
2999     }
3000     Vals.push_back(VE.getTypeID(I.getType()));
3001     Vals.push_back(getEncodedAlign(cast<LoadInst>(I).getAlign()));
3002     Vals.push_back(cast<LoadInst>(I).isVolatile());
3003     if (cast<LoadInst>(I).isAtomic()) {
3004       Vals.push_back(getEncodedOrdering(cast<LoadInst>(I).getOrdering()));
3005       Vals.push_back(getEncodedSyncScopeID(cast<LoadInst>(I).getSyncScopeID()));
3006     }
3007     break;
3008   case Instruction::Store:
3009     if (cast<StoreInst>(I).isAtomic())
3010       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
3011     else
3012       Code = bitc::FUNC_CODE_INST_STORE;
3013     pushValueAndType(I.getOperand(1), InstID, Vals); // ptrty + ptr
3014     pushValueAndType(I.getOperand(0), InstID, Vals); // valty + val
3015     Vals.push_back(getEncodedAlign(cast<StoreInst>(I).getAlign()));
3016     Vals.push_back(cast<StoreInst>(I).isVolatile());
3017     if (cast<StoreInst>(I).isAtomic()) {
3018       Vals.push_back(getEncodedOrdering(cast<StoreInst>(I).getOrdering()));
3019       Vals.push_back(
3020           getEncodedSyncScopeID(cast<StoreInst>(I).getSyncScopeID()));
3021     }
3022     break;
3023   case Instruction::AtomicCmpXchg:
3024     Code = bitc::FUNC_CODE_INST_CMPXCHG;
3025     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
3026     pushValueAndType(I.getOperand(1), InstID, Vals); // cmp.
3027     pushValue(I.getOperand(2), InstID, Vals);        // newval.
3028     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
3029     Vals.push_back(
3030         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
3031     Vals.push_back(
3032         getEncodedSyncScopeID(cast<AtomicCmpXchgInst>(I).getSyncScopeID()));
3033     Vals.push_back(
3034         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
3035     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
3036     break;
3037   case Instruction::AtomicRMW:
3038     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
3039     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
3040     pushValue(I.getOperand(1), InstID, Vals);        // val.
3041     Vals.push_back(
3042         getEncodedRMWOperation(cast<AtomicRMWInst>(I).getOperation()));
3043     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
3044     Vals.push_back(getEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
3045     Vals.push_back(
3046         getEncodedSyncScopeID(cast<AtomicRMWInst>(I).getSyncScopeID()));
3047     break;
3048   case Instruction::Fence:
3049     Code = bitc::FUNC_CODE_INST_FENCE;
3050     Vals.push_back(getEncodedOrdering(cast<FenceInst>(I).getOrdering()));
3051     Vals.push_back(getEncodedSyncScopeID(cast<FenceInst>(I).getSyncScopeID()));
3052     break;
3053   case Instruction::Call: {
3054     const CallInst &CI = cast<CallInst>(I);
3055     FunctionType *FTy = CI.getFunctionType();
3056 
3057     if (CI.hasOperandBundles())
3058       writeOperandBundles(CI, InstID);
3059 
3060     Code = bitc::FUNC_CODE_INST_CALL;
3061 
3062     Vals.push_back(VE.getAttributeListID(CI.getAttributes()));
3063 
3064     unsigned Flags = getOptimizationFlags(&I);
3065     Vals.push_back(CI.getCallingConv() << bitc::CALL_CCONV |
3066                    unsigned(CI.isTailCall()) << bitc::CALL_TAIL |
3067                    unsigned(CI.isMustTailCall()) << bitc::CALL_MUSTTAIL |
3068                    1 << bitc::CALL_EXPLICIT_TYPE |
3069                    unsigned(CI.isNoTailCall()) << bitc::CALL_NOTAIL |
3070                    unsigned(Flags != 0) << bitc::CALL_FMF);
3071     if (Flags != 0)
3072       Vals.push_back(Flags);
3073 
3074     Vals.push_back(VE.getTypeID(FTy));
3075     pushValueAndType(CI.getCalledOperand(), InstID, Vals); // Callee
3076 
3077     // Emit value #'s for the fixed parameters.
3078     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
3079       // Check for labels (can happen with asm labels).
3080       if (FTy->getParamType(i)->isLabelTy())
3081         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
3082       else
3083         pushValue(CI.getArgOperand(i), InstID, Vals); // fixed param.
3084     }
3085 
3086     // Emit type/value pairs for varargs params.
3087     if (FTy->isVarArg()) {
3088       for (unsigned i = FTy->getNumParams(), e = CI.getNumArgOperands();
3089            i != e; ++i)
3090         pushValueAndType(CI.getArgOperand(i), InstID, Vals); // varargs
3091     }
3092     break;
3093   }
3094   case Instruction::VAArg:
3095     Code = bitc::FUNC_CODE_INST_VAARG;
3096     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
3097     pushValue(I.getOperand(0), InstID, Vals);                   // valist.
3098     Vals.push_back(VE.getTypeID(I.getType())); // restype.
3099     break;
3100   case Instruction::Freeze:
3101     Code = bitc::FUNC_CODE_INST_FREEZE;
3102     pushValueAndType(I.getOperand(0), InstID, Vals);
3103     break;
3104   }
3105 
3106   Stream.EmitRecord(Code, Vals, AbbrevToUse);
3107   Vals.clear();
3108 }
3109 
3110 /// Write a GlobalValue VST to the module. The purpose of this data structure is
3111 /// to allow clients to efficiently find the function body.
3112 void ModuleBitcodeWriter::writeGlobalValueSymbolTable(
3113   DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3114   // Get the offset of the VST we are writing, and backpatch it into
3115   // the VST forward declaration record.
3116   uint64_t VSTOffset = Stream.GetCurrentBitNo();
3117   // The BitcodeStartBit was the stream offset of the identification block.
3118   VSTOffset -= bitcodeStartBit();
3119   assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
3120   // Note that we add 1 here because the offset is relative to one word
3121   // before the start of the identification block, which was historically
3122   // always the start of the regular bitcode header.
3123   Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32 + 1);
3124 
3125   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3126 
3127   auto Abbv = std::make_shared<BitCodeAbbrev>();
3128   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
3129   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
3130   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
3131   unsigned FnEntryAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3132 
3133   for (const Function &F : M) {
3134     uint64_t Record[2];
3135 
3136     if (F.isDeclaration())
3137       continue;
3138 
3139     Record[0] = VE.getValueID(&F);
3140 
3141     // Save the word offset of the function (from the start of the
3142     // actual bitcode written to the stream).
3143     uint64_t BitcodeIndex = FunctionToBitcodeIndex[&F] - bitcodeStartBit();
3144     assert((BitcodeIndex & 31) == 0 && "function block not 32-bit aligned");
3145     // Note that we add 1 here because the offset is relative to one word
3146     // before the start of the identification block, which was historically
3147     // always the start of the regular bitcode header.
3148     Record[1] = BitcodeIndex / 32 + 1;
3149 
3150     Stream.EmitRecord(bitc::VST_CODE_FNENTRY, Record, FnEntryAbbrev);
3151   }
3152 
3153   Stream.ExitBlock();
3154 }
3155 
3156 /// Emit names for arguments, instructions and basic blocks in a function.
3157 void ModuleBitcodeWriter::writeFunctionLevelValueSymbolTable(
3158     const ValueSymbolTable &VST) {
3159   if (VST.empty())
3160     return;
3161 
3162   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3163 
3164   // FIXME: Set up the abbrev, we know how many values there are!
3165   // FIXME: We know if the type names can use 7-bit ascii.
3166   SmallVector<uint64_t, 64> NameVals;
3167 
3168   for (const ValueName &Name : VST) {
3169     // Figure out the encoding to use for the name.
3170     StringEncoding Bits = getStringEncoding(Name.getKey());
3171 
3172     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
3173     NameVals.push_back(VE.getValueID(Name.getValue()));
3174 
3175     // VST_CODE_ENTRY:   [valueid, namechar x N]
3176     // VST_CODE_BBENTRY: [bbid, namechar x N]
3177     unsigned Code;
3178     if (isa<BasicBlock>(Name.getValue())) {
3179       Code = bitc::VST_CODE_BBENTRY;
3180       if (Bits == SE_Char6)
3181         AbbrevToUse = VST_BBENTRY_6_ABBREV;
3182     } else {
3183       Code = bitc::VST_CODE_ENTRY;
3184       if (Bits == SE_Char6)
3185         AbbrevToUse = VST_ENTRY_6_ABBREV;
3186       else if (Bits == SE_Fixed7)
3187         AbbrevToUse = VST_ENTRY_7_ABBREV;
3188     }
3189 
3190     for (const auto P : Name.getKey())
3191       NameVals.push_back((unsigned char)P);
3192 
3193     // Emit the finished record.
3194     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
3195     NameVals.clear();
3196   }
3197 
3198   Stream.ExitBlock();
3199 }
3200 
3201 void ModuleBitcodeWriter::writeUseList(UseListOrder &&Order) {
3202   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
3203   unsigned Code;
3204   if (isa<BasicBlock>(Order.V))
3205     Code = bitc::USELIST_CODE_BB;
3206   else
3207     Code = bitc::USELIST_CODE_DEFAULT;
3208 
3209   SmallVector<uint64_t, 64> Record(Order.Shuffle.begin(), Order.Shuffle.end());
3210   Record.push_back(VE.getValueID(Order.V));
3211   Stream.EmitRecord(Code, Record);
3212 }
3213 
3214 void ModuleBitcodeWriter::writeUseListBlock(const Function *F) {
3215   assert(VE.shouldPreserveUseListOrder() &&
3216          "Expected to be preserving use-list order");
3217 
3218   auto hasMore = [&]() {
3219     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
3220   };
3221   if (!hasMore())
3222     // Nothing to do.
3223     return;
3224 
3225   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
3226   while (hasMore()) {
3227     writeUseList(std::move(VE.UseListOrders.back()));
3228     VE.UseListOrders.pop_back();
3229   }
3230   Stream.ExitBlock();
3231 }
3232 
3233 /// Emit a function body to the module stream.
3234 void ModuleBitcodeWriter::writeFunction(
3235     const Function &F,
3236     DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3237   // Save the bitcode index of the start of this function block for recording
3238   // in the VST.
3239   FunctionToBitcodeIndex[&F] = Stream.GetCurrentBitNo();
3240 
3241   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
3242   VE.incorporateFunction(F);
3243 
3244   SmallVector<unsigned, 64> Vals;
3245 
3246   // Emit the number of basic blocks, so the reader can create them ahead of
3247   // time.
3248   Vals.push_back(VE.getBasicBlocks().size());
3249   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
3250   Vals.clear();
3251 
3252   // If there are function-local constants, emit them now.
3253   unsigned CstStart, CstEnd;
3254   VE.getFunctionConstantRange(CstStart, CstEnd);
3255   writeConstants(CstStart, CstEnd, false);
3256 
3257   // If there is function-local metadata, emit it now.
3258   writeFunctionMetadata(F);
3259 
3260   // Keep a running idea of what the instruction ID is.
3261   unsigned InstID = CstEnd;
3262 
3263   bool NeedsMetadataAttachment = F.hasMetadata();
3264 
3265   DILocation *LastDL = nullptr;
3266   // Finally, emit all the instructions, in order.
3267   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
3268     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
3269          I != E; ++I) {
3270       writeInstruction(*I, InstID, Vals);
3271 
3272       if (!I->getType()->isVoidTy())
3273         ++InstID;
3274 
3275       // If the instruction has metadata, write a metadata attachment later.
3276       NeedsMetadataAttachment |= I->hasMetadataOtherThanDebugLoc();
3277 
3278       // If the instruction has a debug location, emit it.
3279       DILocation *DL = I->getDebugLoc();
3280       if (!DL)
3281         continue;
3282 
3283       if (DL == LastDL) {
3284         // Just repeat the same debug loc as last time.
3285         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
3286         continue;
3287       }
3288 
3289       Vals.push_back(DL->getLine());
3290       Vals.push_back(DL->getColumn());
3291       Vals.push_back(VE.getMetadataOrNullID(DL->getScope()));
3292       Vals.push_back(VE.getMetadataOrNullID(DL->getInlinedAt()));
3293       Vals.push_back(DL->isImplicitCode());
3294       Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
3295       Vals.clear();
3296 
3297       LastDL = DL;
3298     }
3299 
3300   // Emit names for all the instructions etc.
3301   if (auto *Symtab = F.getValueSymbolTable())
3302     writeFunctionLevelValueSymbolTable(*Symtab);
3303 
3304   if (NeedsMetadataAttachment)
3305     writeFunctionMetadataAttachment(F);
3306   if (VE.shouldPreserveUseListOrder())
3307     writeUseListBlock(&F);
3308   VE.purgeFunction();
3309   Stream.ExitBlock();
3310 }
3311 
3312 // Emit blockinfo, which defines the standard abbreviations etc.
3313 void ModuleBitcodeWriter::writeBlockInfo() {
3314   // We only want to emit block info records for blocks that have multiple
3315   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
3316   // Other blocks can define their abbrevs inline.
3317   Stream.EnterBlockInfoBlock();
3318 
3319   { // 8-bit fixed-width VST_CODE_ENTRY/VST_CODE_BBENTRY strings.
3320     auto Abbv = std::make_shared<BitCodeAbbrev>();
3321     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
3322     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3323     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3324     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3325     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3326         VST_ENTRY_8_ABBREV)
3327       llvm_unreachable("Unexpected abbrev ordering!");
3328   }
3329 
3330   { // 7-bit fixed width VST_CODE_ENTRY strings.
3331     auto Abbv = std::make_shared<BitCodeAbbrev>();
3332     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3333     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3334     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3335     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3336     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3337         VST_ENTRY_7_ABBREV)
3338       llvm_unreachable("Unexpected abbrev ordering!");
3339   }
3340   { // 6-bit char6 VST_CODE_ENTRY strings.
3341     auto Abbv = std::make_shared<BitCodeAbbrev>();
3342     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3343     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3344     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3345     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3346     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3347         VST_ENTRY_6_ABBREV)
3348       llvm_unreachable("Unexpected abbrev ordering!");
3349   }
3350   { // 6-bit char6 VST_CODE_BBENTRY strings.
3351     auto Abbv = std::make_shared<BitCodeAbbrev>();
3352     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
3353     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3354     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3355     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3356     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3357         VST_BBENTRY_6_ABBREV)
3358       llvm_unreachable("Unexpected abbrev ordering!");
3359   }
3360 
3361   { // SETTYPE abbrev for CONSTANTS_BLOCK.
3362     auto Abbv = std::make_shared<BitCodeAbbrev>();
3363     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
3364     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
3365                               VE.computeBitsRequiredForTypeIndicies()));
3366     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3367         CONSTANTS_SETTYPE_ABBREV)
3368       llvm_unreachable("Unexpected abbrev ordering!");
3369   }
3370 
3371   { // INTEGER abbrev for CONSTANTS_BLOCK.
3372     auto Abbv = std::make_shared<BitCodeAbbrev>();
3373     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
3374     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3375     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3376         CONSTANTS_INTEGER_ABBREV)
3377       llvm_unreachable("Unexpected abbrev ordering!");
3378   }
3379 
3380   { // CE_CAST abbrev for CONSTANTS_BLOCK.
3381     auto Abbv = std::make_shared<BitCodeAbbrev>();
3382     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
3383     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
3384     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
3385                               VE.computeBitsRequiredForTypeIndicies()));
3386     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
3387 
3388     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3389         CONSTANTS_CE_CAST_Abbrev)
3390       llvm_unreachable("Unexpected abbrev ordering!");
3391   }
3392   { // NULL abbrev for CONSTANTS_BLOCK.
3393     auto Abbv = std::make_shared<BitCodeAbbrev>();
3394     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
3395     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3396         CONSTANTS_NULL_Abbrev)
3397       llvm_unreachable("Unexpected abbrev ordering!");
3398   }
3399 
3400   // FIXME: This should only use space for first class types!
3401 
3402   { // INST_LOAD abbrev for FUNCTION_BLOCK.
3403     auto Abbv = std::make_shared<BitCodeAbbrev>();
3404     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
3405     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
3406     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
3407                               VE.computeBitsRequiredForTypeIndicies()));
3408     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
3409     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
3410     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3411         FUNCTION_INST_LOAD_ABBREV)
3412       llvm_unreachable("Unexpected abbrev ordering!");
3413   }
3414   { // INST_UNOP abbrev for FUNCTION_BLOCK.
3415     auto Abbv = std::make_shared<BitCodeAbbrev>();
3416     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3417     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3418     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3419     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3420         FUNCTION_INST_UNOP_ABBREV)
3421       llvm_unreachable("Unexpected abbrev ordering!");
3422   }
3423   { // INST_UNOP_FLAGS abbrev for FUNCTION_BLOCK.
3424     auto Abbv = std::make_shared<BitCodeAbbrev>();
3425     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3426     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3427     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3428     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3429     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3430         FUNCTION_INST_UNOP_FLAGS_ABBREV)
3431       llvm_unreachable("Unexpected abbrev ordering!");
3432   }
3433   { // INST_BINOP abbrev for FUNCTION_BLOCK.
3434     auto Abbv = std::make_shared<BitCodeAbbrev>();
3435     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3436     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3437     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3438     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3439     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3440         FUNCTION_INST_BINOP_ABBREV)
3441       llvm_unreachable("Unexpected abbrev ordering!");
3442   }
3443   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
3444     auto Abbv = std::make_shared<BitCodeAbbrev>();
3445     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3446     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3447     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3448     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3449     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3450     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3451         FUNCTION_INST_BINOP_FLAGS_ABBREV)
3452       llvm_unreachable("Unexpected abbrev ordering!");
3453   }
3454   { // INST_CAST abbrev for FUNCTION_BLOCK.
3455     auto Abbv = std::make_shared<BitCodeAbbrev>();
3456     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
3457     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
3458     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
3459                               VE.computeBitsRequiredForTypeIndicies()));
3460     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
3461     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3462         FUNCTION_INST_CAST_ABBREV)
3463       llvm_unreachable("Unexpected abbrev ordering!");
3464   }
3465 
3466   { // INST_RET abbrev for FUNCTION_BLOCK.
3467     auto Abbv = std::make_shared<BitCodeAbbrev>();
3468     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3469     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3470         FUNCTION_INST_RET_VOID_ABBREV)
3471       llvm_unreachable("Unexpected abbrev ordering!");
3472   }
3473   { // INST_RET abbrev for FUNCTION_BLOCK.
3474     auto Abbv = std::make_shared<BitCodeAbbrev>();
3475     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3476     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
3477     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3478         FUNCTION_INST_RET_VAL_ABBREV)
3479       llvm_unreachable("Unexpected abbrev ordering!");
3480   }
3481   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
3482     auto Abbv = std::make_shared<BitCodeAbbrev>();
3483     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
3484     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3485         FUNCTION_INST_UNREACHABLE_ABBREV)
3486       llvm_unreachable("Unexpected abbrev ordering!");
3487   }
3488   {
3489     auto Abbv = std::make_shared<BitCodeAbbrev>();
3490     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_GEP));
3491     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
3492     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, // dest ty
3493                               Log2_32_Ceil(VE.getTypes().size() + 1)));
3494     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3495     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
3496     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3497         FUNCTION_INST_GEP_ABBREV)
3498       llvm_unreachable("Unexpected abbrev ordering!");
3499   }
3500 
3501   Stream.ExitBlock();
3502 }
3503 
3504 /// Write the module path strings, currently only used when generating
3505 /// a combined index file.
3506 void IndexBitcodeWriter::writeModStrings() {
3507   Stream.EnterSubblock(bitc::MODULE_STRTAB_BLOCK_ID, 3);
3508 
3509   // TODO: See which abbrev sizes we actually need to emit
3510 
3511   // 8-bit fixed-width MST_ENTRY strings.
3512   auto Abbv = std::make_shared<BitCodeAbbrev>();
3513   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3514   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3515   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3516   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3517   unsigned Abbrev8Bit = Stream.EmitAbbrev(std::move(Abbv));
3518 
3519   // 7-bit fixed width MST_ENTRY strings.
3520   Abbv = std::make_shared<BitCodeAbbrev>();
3521   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3522   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3523   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3524   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3525   unsigned Abbrev7Bit = Stream.EmitAbbrev(std::move(Abbv));
3526 
3527   // 6-bit char6 MST_ENTRY strings.
3528   Abbv = std::make_shared<BitCodeAbbrev>();
3529   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3530   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3531   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3532   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3533   unsigned Abbrev6Bit = Stream.EmitAbbrev(std::move(Abbv));
3534 
3535   // Module Hash, 160 bits SHA1. Optionally, emitted after each MST_CODE_ENTRY.
3536   Abbv = std::make_shared<BitCodeAbbrev>();
3537   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_HASH));
3538   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3539   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3540   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3541   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3542   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3543   unsigned AbbrevHash = Stream.EmitAbbrev(std::move(Abbv));
3544 
3545   SmallVector<unsigned, 64> Vals;
3546   forEachModule(
3547       [&](const StringMapEntry<std::pair<uint64_t, ModuleHash>> &MPSE) {
3548         StringRef Key = MPSE.getKey();
3549         const auto &Value = MPSE.getValue();
3550         StringEncoding Bits = getStringEncoding(Key);
3551         unsigned AbbrevToUse = Abbrev8Bit;
3552         if (Bits == SE_Char6)
3553           AbbrevToUse = Abbrev6Bit;
3554         else if (Bits == SE_Fixed7)
3555           AbbrevToUse = Abbrev7Bit;
3556 
3557         Vals.push_back(Value.first);
3558         Vals.append(Key.begin(), Key.end());
3559 
3560         // Emit the finished record.
3561         Stream.EmitRecord(bitc::MST_CODE_ENTRY, Vals, AbbrevToUse);
3562 
3563         // Emit an optional hash for the module now
3564         const auto &Hash = Value.second;
3565         if (llvm::any_of(Hash, [](uint32_t H) { return H; })) {
3566           Vals.assign(Hash.begin(), Hash.end());
3567           // Emit the hash record.
3568           Stream.EmitRecord(bitc::MST_CODE_HASH, Vals, AbbrevHash);
3569         }
3570 
3571         Vals.clear();
3572       });
3573   Stream.ExitBlock();
3574 }
3575 
3576 /// Write the function type metadata related records that need to appear before
3577 /// a function summary entry (whether per-module or combined).
3578 template <typename Fn>
3579 static void writeFunctionTypeMetadataRecords(BitstreamWriter &Stream,
3580                                              FunctionSummary *FS,
3581                                              Fn GetValueID) {
3582   if (!FS->type_tests().empty())
3583     Stream.EmitRecord(bitc::FS_TYPE_TESTS, FS->type_tests());
3584 
3585   SmallVector<uint64_t, 64> Record;
3586 
3587   auto WriteVFuncIdVec = [&](uint64_t Ty,
3588                              ArrayRef<FunctionSummary::VFuncId> VFs) {
3589     if (VFs.empty())
3590       return;
3591     Record.clear();
3592     for (auto &VF : VFs) {
3593       Record.push_back(VF.GUID);
3594       Record.push_back(VF.Offset);
3595     }
3596     Stream.EmitRecord(Ty, Record);
3597   };
3598 
3599   WriteVFuncIdVec(bitc::FS_TYPE_TEST_ASSUME_VCALLS,
3600                   FS->type_test_assume_vcalls());
3601   WriteVFuncIdVec(bitc::FS_TYPE_CHECKED_LOAD_VCALLS,
3602                   FS->type_checked_load_vcalls());
3603 
3604   auto WriteConstVCallVec = [&](uint64_t Ty,
3605                                 ArrayRef<FunctionSummary::ConstVCall> VCs) {
3606     for (auto &VC : VCs) {
3607       Record.clear();
3608       Record.push_back(VC.VFunc.GUID);
3609       Record.push_back(VC.VFunc.Offset);
3610       Record.insert(Record.end(), VC.Args.begin(), VC.Args.end());
3611       Stream.EmitRecord(Ty, Record);
3612     }
3613   };
3614 
3615   WriteConstVCallVec(bitc::FS_TYPE_TEST_ASSUME_CONST_VCALL,
3616                      FS->type_test_assume_const_vcalls());
3617   WriteConstVCallVec(bitc::FS_TYPE_CHECKED_LOAD_CONST_VCALL,
3618                      FS->type_checked_load_const_vcalls());
3619 
3620   auto WriteRange = [&](ConstantRange Range) {
3621     Range = Range.sextOrTrunc(FunctionSummary::ParamAccess::RangeWidth);
3622     assert(Range.getLower().getNumWords() == 1);
3623     assert(Range.getUpper().getNumWords() == 1);
3624     emitSignedInt64(Record, *Range.getLower().getRawData());
3625     emitSignedInt64(Record, *Range.getUpper().getRawData());
3626   };
3627 
3628   if (!FS->paramAccesses().empty()) {
3629     Record.clear();
3630     for (auto &Arg : FS->paramAccesses()) {
3631       size_t UndoSize = Record.size();
3632       Record.push_back(Arg.ParamNo);
3633       WriteRange(Arg.Use);
3634       Record.push_back(Arg.Calls.size());
3635       for (auto &Call : Arg.Calls) {
3636         Record.push_back(Call.ParamNo);
3637         Optional<unsigned> ValueID = GetValueID(Call.Callee);
3638         if (!ValueID) {
3639           // If ValueID is unknown we can't drop just this call, we must drop
3640           // entire parameter.
3641           Record.resize(UndoSize);
3642           break;
3643         }
3644         Record.push_back(*ValueID);
3645         WriteRange(Call.Offsets);
3646       }
3647     }
3648     if (!Record.empty())
3649       Stream.EmitRecord(bitc::FS_PARAM_ACCESS, Record);
3650   }
3651 }
3652 
3653 /// Collect type IDs from type tests used by function.
3654 static void
3655 getReferencedTypeIds(FunctionSummary *FS,
3656                      std::set<GlobalValue::GUID> &ReferencedTypeIds) {
3657   if (!FS->type_tests().empty())
3658     for (auto &TT : FS->type_tests())
3659       ReferencedTypeIds.insert(TT);
3660 
3661   auto GetReferencedTypesFromVFuncIdVec =
3662       [&](ArrayRef<FunctionSummary::VFuncId> VFs) {
3663         for (auto &VF : VFs)
3664           ReferencedTypeIds.insert(VF.GUID);
3665       };
3666 
3667   GetReferencedTypesFromVFuncIdVec(FS->type_test_assume_vcalls());
3668   GetReferencedTypesFromVFuncIdVec(FS->type_checked_load_vcalls());
3669 
3670   auto GetReferencedTypesFromConstVCallVec =
3671       [&](ArrayRef<FunctionSummary::ConstVCall> VCs) {
3672         for (auto &VC : VCs)
3673           ReferencedTypeIds.insert(VC.VFunc.GUID);
3674       };
3675 
3676   GetReferencedTypesFromConstVCallVec(FS->type_test_assume_const_vcalls());
3677   GetReferencedTypesFromConstVCallVec(FS->type_checked_load_const_vcalls());
3678 }
3679 
3680 static void writeWholeProgramDevirtResolutionByArg(
3681     SmallVector<uint64_t, 64> &NameVals, const std::vector<uint64_t> &args,
3682     const WholeProgramDevirtResolution::ByArg &ByArg) {
3683   NameVals.push_back(args.size());
3684   NameVals.insert(NameVals.end(), args.begin(), args.end());
3685 
3686   NameVals.push_back(ByArg.TheKind);
3687   NameVals.push_back(ByArg.Info);
3688   NameVals.push_back(ByArg.Byte);
3689   NameVals.push_back(ByArg.Bit);
3690 }
3691 
3692 static void writeWholeProgramDevirtResolution(
3693     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3694     uint64_t Id, const WholeProgramDevirtResolution &Wpd) {
3695   NameVals.push_back(Id);
3696 
3697   NameVals.push_back(Wpd.TheKind);
3698   NameVals.push_back(StrtabBuilder.add(Wpd.SingleImplName));
3699   NameVals.push_back(Wpd.SingleImplName.size());
3700 
3701   NameVals.push_back(Wpd.ResByArg.size());
3702   for (auto &A : Wpd.ResByArg)
3703     writeWholeProgramDevirtResolutionByArg(NameVals, A.first, A.second);
3704 }
3705 
3706 static void writeTypeIdSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
3707                                      StringTableBuilder &StrtabBuilder,
3708                                      const std::string &Id,
3709                                      const TypeIdSummary &Summary) {
3710   NameVals.push_back(StrtabBuilder.add(Id));
3711   NameVals.push_back(Id.size());
3712 
3713   NameVals.push_back(Summary.TTRes.TheKind);
3714   NameVals.push_back(Summary.TTRes.SizeM1BitWidth);
3715   NameVals.push_back(Summary.TTRes.AlignLog2);
3716   NameVals.push_back(Summary.TTRes.SizeM1);
3717   NameVals.push_back(Summary.TTRes.BitMask);
3718   NameVals.push_back(Summary.TTRes.InlineBits);
3719 
3720   for (auto &W : Summary.WPDRes)
3721     writeWholeProgramDevirtResolution(NameVals, StrtabBuilder, W.first,
3722                                       W.second);
3723 }
3724 
3725 static void writeTypeIdCompatibleVtableSummaryRecord(
3726     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3727     const std::string &Id, const TypeIdCompatibleVtableInfo &Summary,
3728     ValueEnumerator &VE) {
3729   NameVals.push_back(StrtabBuilder.add(Id));
3730   NameVals.push_back(Id.size());
3731 
3732   for (auto &P : Summary) {
3733     NameVals.push_back(P.AddressPointOffset);
3734     NameVals.push_back(VE.getValueID(P.VTableVI.getValue()));
3735   }
3736 }
3737 
3738 // Helper to emit a single function summary record.
3739 void ModuleBitcodeWriterBase::writePerModuleFunctionSummaryRecord(
3740     SmallVector<uint64_t, 64> &NameVals, GlobalValueSummary *Summary,
3741     unsigned ValueID, unsigned FSCallsAbbrev, unsigned FSCallsProfileAbbrev,
3742     const Function &F) {
3743   NameVals.push_back(ValueID);
3744 
3745   FunctionSummary *FS = cast<FunctionSummary>(Summary);
3746 
3747   writeFunctionTypeMetadataRecords(
3748       Stream, FS, [&](const ValueInfo &VI) -> Optional<unsigned> {
3749         return {VE.getValueID(VI.getValue())};
3750       });
3751 
3752   auto SpecialRefCnts = FS->specialRefCounts();
3753   NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
3754   NameVals.push_back(FS->instCount());
3755   NameVals.push_back(getEncodedFFlags(FS->fflags()));
3756   NameVals.push_back(FS->refs().size());
3757   NameVals.push_back(SpecialRefCnts.first);  // rorefcnt
3758   NameVals.push_back(SpecialRefCnts.second); // worefcnt
3759 
3760   for (auto &RI : FS->refs())
3761     NameVals.push_back(VE.getValueID(RI.getValue()));
3762 
3763   bool HasProfileData =
3764       F.hasProfileData() || ForceSummaryEdgesCold != FunctionSummary::FSHT_None;
3765   for (auto &ECI : FS->calls()) {
3766     NameVals.push_back(getValueId(ECI.first));
3767     if (HasProfileData)
3768       NameVals.push_back(static_cast<uint8_t>(ECI.second.Hotness));
3769     else if (WriteRelBFToSummary)
3770       NameVals.push_back(ECI.second.RelBlockFreq);
3771   }
3772 
3773   unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
3774   unsigned Code =
3775       (HasProfileData ? bitc::FS_PERMODULE_PROFILE
3776                       : (WriteRelBFToSummary ? bitc::FS_PERMODULE_RELBF
3777                                              : bitc::FS_PERMODULE));
3778 
3779   // Emit the finished record.
3780   Stream.EmitRecord(Code, NameVals, FSAbbrev);
3781   NameVals.clear();
3782 }
3783 
3784 // Collect the global value references in the given variable's initializer,
3785 // and emit them in a summary record.
3786 void ModuleBitcodeWriterBase::writeModuleLevelReferences(
3787     const GlobalVariable &V, SmallVector<uint64_t, 64> &NameVals,
3788     unsigned FSModRefsAbbrev, unsigned FSModVTableRefsAbbrev) {
3789   auto VI = Index->getValueInfo(V.getGUID());
3790   if (!VI || VI.getSummaryList().empty()) {
3791     // Only declarations should not have a summary (a declaration might however
3792     // have a summary if the def was in module level asm).
3793     assert(V.isDeclaration());
3794     return;
3795   }
3796   auto *Summary = VI.getSummaryList()[0].get();
3797   NameVals.push_back(VE.getValueID(&V));
3798   GlobalVarSummary *VS = cast<GlobalVarSummary>(Summary);
3799   NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
3800   NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
3801 
3802   auto VTableFuncs = VS->vTableFuncs();
3803   if (!VTableFuncs.empty())
3804     NameVals.push_back(VS->refs().size());
3805 
3806   unsigned SizeBeforeRefs = NameVals.size();
3807   for (auto &RI : VS->refs())
3808     NameVals.push_back(VE.getValueID(RI.getValue()));
3809   // Sort the refs for determinism output, the vector returned by FS->refs() has
3810   // been initialized from a DenseSet.
3811   llvm::sort(NameVals.begin() + SizeBeforeRefs, NameVals.end());
3812 
3813   if (VTableFuncs.empty())
3814     Stream.EmitRecord(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS, NameVals,
3815                       FSModRefsAbbrev);
3816   else {
3817     // VTableFuncs pairs should already be sorted by offset.
3818     for (auto &P : VTableFuncs) {
3819       NameVals.push_back(VE.getValueID(P.FuncVI.getValue()));
3820       NameVals.push_back(P.VTableOffset);
3821     }
3822 
3823     Stream.EmitRecord(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS, NameVals,
3824                       FSModVTableRefsAbbrev);
3825   }
3826   NameVals.clear();
3827 }
3828 
3829 /// Emit the per-module summary section alongside the rest of
3830 /// the module's bitcode.
3831 void ModuleBitcodeWriterBase::writePerModuleGlobalValueSummary() {
3832   // By default we compile with ThinLTO if the module has a summary, but the
3833   // client can request full LTO with a module flag.
3834   bool IsThinLTO = true;
3835   if (auto *MD =
3836           mdconst::extract_or_null<ConstantInt>(M.getModuleFlag("ThinLTO")))
3837     IsThinLTO = MD->getZExtValue();
3838   Stream.EnterSubblock(IsThinLTO ? bitc::GLOBALVAL_SUMMARY_BLOCK_ID
3839                                  : bitc::FULL_LTO_GLOBALVAL_SUMMARY_BLOCK_ID,
3840                        4);
3841 
3842   Stream.EmitRecord(
3843       bitc::FS_VERSION,
3844       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
3845 
3846   // Write the index flags.
3847   uint64_t Flags = 0;
3848   // Bits 1-3 are set only in the combined index, skip them.
3849   if (Index->enableSplitLTOUnit())
3850     Flags |= 0x8;
3851   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Flags});
3852 
3853   if (Index->begin() == Index->end()) {
3854     Stream.ExitBlock();
3855     return;
3856   }
3857 
3858   for (const auto &GVI : valueIds()) {
3859     Stream.EmitRecord(bitc::FS_VALUE_GUID,
3860                       ArrayRef<uint64_t>{GVI.second, GVI.first});
3861   }
3862 
3863   // Abbrev for FS_PERMODULE_PROFILE.
3864   auto Abbv = std::make_shared<BitCodeAbbrev>();
3865   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_PROFILE));
3866   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3867   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3868   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3869   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3870   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3871   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
3872   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
3873   // numrefs x valueid, n x (valueid, hotness)
3874   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3875   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3876   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3877 
3878   // Abbrev for FS_PERMODULE or FS_PERMODULE_RELBF.
3879   Abbv = std::make_shared<BitCodeAbbrev>();
3880   if (WriteRelBFToSummary)
3881     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_RELBF));
3882   else
3883     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE));
3884   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3885   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3886   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3887   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3888   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3889   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
3890   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
3891   // numrefs x valueid, n x (valueid [, rel_block_freq])
3892   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3893   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3894   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3895 
3896   // Abbrev for FS_PERMODULE_GLOBALVAR_INIT_REFS.
3897   Abbv = std::make_shared<BitCodeAbbrev>();
3898   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS));
3899   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
3900   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
3901   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));  // valueids
3902   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3903   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3904 
3905   // Abbrev for FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS.
3906   Abbv = std::make_shared<BitCodeAbbrev>();
3907   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS));
3908   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
3909   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
3910   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numrefs
3911   // numrefs x valueid, n x (valueid , offset)
3912   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3913   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3914   unsigned FSModVTableRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3915 
3916   // Abbrev for FS_ALIAS.
3917   Abbv = std::make_shared<BitCodeAbbrev>();
3918   Abbv->Add(BitCodeAbbrevOp(bitc::FS_ALIAS));
3919   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3920   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3921   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3922   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3923 
3924   // Abbrev for FS_TYPE_ID_METADATA
3925   Abbv = std::make_shared<BitCodeAbbrev>();
3926   Abbv->Add(BitCodeAbbrevOp(bitc::FS_TYPE_ID_METADATA));
3927   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid strtab index
3928   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid length
3929   // n x (valueid , offset)
3930   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3931   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3932   unsigned TypeIdCompatibleVtableAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3933 
3934   SmallVector<uint64_t, 64> NameVals;
3935   // Iterate over the list of functions instead of the Index to
3936   // ensure the ordering is stable.
3937   for (const Function &F : M) {
3938     // Summary emission does not support anonymous functions, they have to
3939     // renamed using the anonymous function renaming pass.
3940     if (!F.hasName())
3941       report_fatal_error("Unexpected anonymous function when writing summary");
3942 
3943     ValueInfo VI = Index->getValueInfo(F.getGUID());
3944     if (!VI || VI.getSummaryList().empty()) {
3945       // Only declarations should not have a summary (a declaration might
3946       // however have a summary if the def was in module level asm).
3947       assert(F.isDeclaration());
3948       continue;
3949     }
3950     auto *Summary = VI.getSummaryList()[0].get();
3951     writePerModuleFunctionSummaryRecord(NameVals, Summary, VE.getValueID(&F),
3952                                         FSCallsAbbrev, FSCallsProfileAbbrev, F);
3953   }
3954 
3955   // Capture references from GlobalVariable initializers, which are outside
3956   // of a function scope.
3957   for (const GlobalVariable &G : M.globals())
3958     writeModuleLevelReferences(G, NameVals, FSModRefsAbbrev,
3959                                FSModVTableRefsAbbrev);
3960 
3961   for (const GlobalAlias &A : M.aliases()) {
3962     auto *Aliasee = A.getBaseObject();
3963     if (!Aliasee->hasName())
3964       // Nameless function don't have an entry in the summary, skip it.
3965       continue;
3966     auto AliasId = VE.getValueID(&A);
3967     auto AliaseeId = VE.getValueID(Aliasee);
3968     NameVals.push_back(AliasId);
3969     auto *Summary = Index->getGlobalValueSummary(A);
3970     AliasSummary *AS = cast<AliasSummary>(Summary);
3971     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
3972     NameVals.push_back(AliaseeId);
3973     Stream.EmitRecord(bitc::FS_ALIAS, NameVals, FSAliasAbbrev);
3974     NameVals.clear();
3975   }
3976 
3977   for (auto &S : Index->typeIdCompatibleVtableMap()) {
3978     writeTypeIdCompatibleVtableSummaryRecord(NameVals, StrtabBuilder, S.first,
3979                                              S.second, VE);
3980     Stream.EmitRecord(bitc::FS_TYPE_ID_METADATA, NameVals,
3981                       TypeIdCompatibleVtableAbbrev);
3982     NameVals.clear();
3983   }
3984 
3985   Stream.EmitRecord(bitc::FS_BLOCK_COUNT,
3986                     ArrayRef<uint64_t>{Index->getBlockCount()});
3987 
3988   Stream.ExitBlock();
3989 }
3990 
3991 /// Emit the combined summary section into the combined index file.
3992 void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
3993   Stream.EnterSubblock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID, 3);
3994   Stream.EmitRecord(
3995       bitc::FS_VERSION,
3996       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
3997 
3998   // Write the index flags.
3999   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Index.getFlags()});
4000 
4001   for (const auto &GVI : valueIds()) {
4002     Stream.EmitRecord(bitc::FS_VALUE_GUID,
4003                       ArrayRef<uint64_t>{GVI.second, GVI.first});
4004   }
4005 
4006   // Abbrev for FS_COMBINED.
4007   auto Abbv = std::make_shared<BitCodeAbbrev>();
4008   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED));
4009   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4010   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4011   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4012   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4013   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4014   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
4015   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4016   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4017   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4018   // numrefs x valueid, n x (valueid)
4019   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4020   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4021   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4022 
4023   // Abbrev for FS_COMBINED_PROFILE.
4024   Abbv = std::make_shared<BitCodeAbbrev>();
4025   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_PROFILE));
4026   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4027   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4028   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4029   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4030   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4031   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
4032   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4033   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4034   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4035   // numrefs x valueid, n x (valueid, hotness)
4036   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4037   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4038   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4039 
4040   // Abbrev for FS_COMBINED_GLOBALVAR_INIT_REFS.
4041   Abbv = std::make_shared<BitCodeAbbrev>();
4042   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS));
4043   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4044   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4045   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4046   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));    // valueids
4047   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4048   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4049 
4050   // Abbrev for FS_COMBINED_ALIAS.
4051   Abbv = std::make_shared<BitCodeAbbrev>();
4052   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_ALIAS));
4053   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4054   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4055   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4056   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4057   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4058 
4059   // The aliases are emitted as a post-pass, and will point to the value
4060   // id of the aliasee. Save them in a vector for post-processing.
4061   SmallVector<AliasSummary *, 64> Aliases;
4062 
4063   // Save the value id for each summary for alias emission.
4064   DenseMap<const GlobalValueSummary *, unsigned> SummaryToValueIdMap;
4065 
4066   SmallVector<uint64_t, 64> NameVals;
4067 
4068   // Set that will be populated during call to writeFunctionTypeMetadataRecords
4069   // with the type ids referenced by this index file.
4070   std::set<GlobalValue::GUID> ReferencedTypeIds;
4071 
4072   // For local linkage, we also emit the original name separately
4073   // immediately after the record.
4074   auto MaybeEmitOriginalName = [&](GlobalValueSummary &S) {
4075     if (!GlobalValue::isLocalLinkage(S.linkage()))
4076       return;
4077     NameVals.push_back(S.getOriginalName());
4078     Stream.EmitRecord(bitc::FS_COMBINED_ORIGINAL_NAME, NameVals);
4079     NameVals.clear();
4080   };
4081 
4082   std::set<GlobalValue::GUID> DefOrUseGUIDs;
4083   forEachSummary([&](GVInfo I, bool IsAliasee) {
4084     GlobalValueSummary *S = I.second;
4085     assert(S);
4086     DefOrUseGUIDs.insert(I.first);
4087     for (const ValueInfo &VI : S->refs())
4088       DefOrUseGUIDs.insert(VI.getGUID());
4089 
4090     auto ValueId = getValueId(I.first);
4091     assert(ValueId);
4092     SummaryToValueIdMap[S] = *ValueId;
4093 
4094     // If this is invoked for an aliasee, we want to record the above
4095     // mapping, but then not emit a summary entry (if the aliasee is
4096     // to be imported, we will invoke this separately with IsAliasee=false).
4097     if (IsAliasee)
4098       return;
4099 
4100     if (auto *AS = dyn_cast<AliasSummary>(S)) {
4101       // Will process aliases as a post-pass because the reader wants all
4102       // global to be loaded first.
4103       Aliases.push_back(AS);
4104       return;
4105     }
4106 
4107     if (auto *VS = dyn_cast<GlobalVarSummary>(S)) {
4108       NameVals.push_back(*ValueId);
4109       NameVals.push_back(Index.getModuleId(VS->modulePath()));
4110       NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
4111       NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
4112       for (auto &RI : VS->refs()) {
4113         auto RefValueId = getValueId(RI.getGUID());
4114         if (!RefValueId)
4115           continue;
4116         NameVals.push_back(*RefValueId);
4117       }
4118 
4119       // Emit the finished record.
4120       Stream.EmitRecord(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS, NameVals,
4121                         FSModRefsAbbrev);
4122       NameVals.clear();
4123       MaybeEmitOriginalName(*S);
4124       return;
4125     }
4126 
4127     auto GetValueId = [&](const ValueInfo &VI) -> Optional<unsigned> {
4128       GlobalValue::GUID GUID = VI.getGUID();
4129       Optional<unsigned> CallValueId = getValueId(GUID);
4130       if (CallValueId)
4131         return CallValueId;
4132       // For SamplePGO, the indirect call targets for local functions will
4133       // have its original name annotated in profile. We try to find the
4134       // corresponding PGOFuncName as the GUID.
4135       GUID = Index.getGUIDFromOriginalID(GUID);
4136       if (!GUID)
4137         return None;
4138       CallValueId = getValueId(GUID);
4139       if (!CallValueId)
4140         return None;
4141       // The mapping from OriginalId to GUID may return a GUID
4142       // that corresponds to a static variable. Filter it out here.
4143       // This can happen when
4144       // 1) There is a call to a library function which does not have
4145       // a CallValidId;
4146       // 2) There is a static variable with the  OriginalGUID identical
4147       // to the GUID of the library function in 1);
4148       // When this happens, the logic for SamplePGO kicks in and
4149       // the static variable in 2) will be found, which needs to be
4150       // filtered out.
4151       auto *GVSum = Index.getGlobalValueSummary(GUID, false);
4152       if (GVSum && GVSum->getSummaryKind() == GlobalValueSummary::GlobalVarKind)
4153         return None;
4154       return CallValueId;
4155     };
4156 
4157     auto *FS = cast<FunctionSummary>(S);
4158     writeFunctionTypeMetadataRecords(Stream, FS, GetValueId);
4159     getReferencedTypeIds(FS, ReferencedTypeIds);
4160 
4161     NameVals.push_back(*ValueId);
4162     NameVals.push_back(Index.getModuleId(FS->modulePath()));
4163     NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
4164     NameVals.push_back(FS->instCount());
4165     NameVals.push_back(getEncodedFFlags(FS->fflags()));
4166     NameVals.push_back(FS->entryCount());
4167 
4168     // Fill in below
4169     NameVals.push_back(0); // numrefs
4170     NameVals.push_back(0); // rorefcnt
4171     NameVals.push_back(0); // worefcnt
4172 
4173     unsigned Count = 0, RORefCnt = 0, WORefCnt = 0;
4174     for (auto &RI : FS->refs()) {
4175       auto RefValueId = getValueId(RI.getGUID());
4176       if (!RefValueId)
4177         continue;
4178       NameVals.push_back(*RefValueId);
4179       if (RI.isReadOnly())
4180         RORefCnt++;
4181       else if (RI.isWriteOnly())
4182         WORefCnt++;
4183       Count++;
4184     }
4185     NameVals[6] = Count;
4186     NameVals[7] = RORefCnt;
4187     NameVals[8] = WORefCnt;
4188 
4189     bool HasProfileData = false;
4190     for (auto &EI : FS->calls()) {
4191       HasProfileData |=
4192           EI.second.getHotness() != CalleeInfo::HotnessType::Unknown;
4193       if (HasProfileData)
4194         break;
4195     }
4196 
4197     for (auto &EI : FS->calls()) {
4198       // If this GUID doesn't have a value id, it doesn't have a function
4199       // summary and we don't need to record any calls to it.
4200       Optional<unsigned> CallValueId = GetValueId(EI.first);
4201       if (!CallValueId)
4202         continue;
4203       NameVals.push_back(*CallValueId);
4204       if (HasProfileData)
4205         NameVals.push_back(static_cast<uint8_t>(EI.second.Hotness));
4206     }
4207 
4208     unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
4209     unsigned Code =
4210         (HasProfileData ? bitc::FS_COMBINED_PROFILE : bitc::FS_COMBINED);
4211 
4212     // Emit the finished record.
4213     Stream.EmitRecord(Code, NameVals, FSAbbrev);
4214     NameVals.clear();
4215     MaybeEmitOriginalName(*S);
4216   });
4217 
4218   for (auto *AS : Aliases) {
4219     auto AliasValueId = SummaryToValueIdMap[AS];
4220     assert(AliasValueId);
4221     NameVals.push_back(AliasValueId);
4222     NameVals.push_back(Index.getModuleId(AS->modulePath()));
4223     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
4224     auto AliaseeValueId = SummaryToValueIdMap[&AS->getAliasee()];
4225     assert(AliaseeValueId);
4226     NameVals.push_back(AliaseeValueId);
4227 
4228     // Emit the finished record.
4229     Stream.EmitRecord(bitc::FS_COMBINED_ALIAS, NameVals, FSAliasAbbrev);
4230     NameVals.clear();
4231     MaybeEmitOriginalName(*AS);
4232 
4233     if (auto *FS = dyn_cast<FunctionSummary>(&AS->getAliasee()))
4234       getReferencedTypeIds(FS, ReferencedTypeIds);
4235   }
4236 
4237   if (!Index.cfiFunctionDefs().empty()) {
4238     for (auto &S : Index.cfiFunctionDefs()) {
4239       if (DefOrUseGUIDs.count(
4240               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4241         NameVals.push_back(StrtabBuilder.add(S));
4242         NameVals.push_back(S.size());
4243       }
4244     }
4245     if (!NameVals.empty()) {
4246       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DEFS, NameVals);
4247       NameVals.clear();
4248     }
4249   }
4250 
4251   if (!Index.cfiFunctionDecls().empty()) {
4252     for (auto &S : Index.cfiFunctionDecls()) {
4253       if (DefOrUseGUIDs.count(
4254               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4255         NameVals.push_back(StrtabBuilder.add(S));
4256         NameVals.push_back(S.size());
4257       }
4258     }
4259     if (!NameVals.empty()) {
4260       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DECLS, NameVals);
4261       NameVals.clear();
4262     }
4263   }
4264 
4265   // Walk the GUIDs that were referenced, and write the
4266   // corresponding type id records.
4267   for (auto &T : ReferencedTypeIds) {
4268     auto TidIter = Index.typeIds().equal_range(T);
4269     for (auto It = TidIter.first; It != TidIter.second; ++It) {
4270       writeTypeIdSummaryRecord(NameVals, StrtabBuilder, It->second.first,
4271                                It->second.second);
4272       Stream.EmitRecord(bitc::FS_TYPE_ID, NameVals);
4273       NameVals.clear();
4274     }
4275   }
4276 
4277   Stream.EmitRecord(bitc::FS_BLOCK_COUNT,
4278                     ArrayRef<uint64_t>{Index.getBlockCount()});
4279 
4280   Stream.ExitBlock();
4281 }
4282 
4283 /// Create the "IDENTIFICATION_BLOCK_ID" containing a single string with the
4284 /// current llvm version, and a record for the epoch number.
4285 static void writeIdentificationBlock(BitstreamWriter &Stream) {
4286   Stream.EnterSubblock(bitc::IDENTIFICATION_BLOCK_ID, 5);
4287 
4288   // Write the "user readable" string identifying the bitcode producer
4289   auto Abbv = std::make_shared<BitCodeAbbrev>();
4290   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_STRING));
4291   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4292   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
4293   auto StringAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4294   writeStringRecord(Stream, bitc::IDENTIFICATION_CODE_STRING,
4295                     "LLVM" LLVM_VERSION_STRING, StringAbbrev);
4296 
4297   // Write the epoch version
4298   Abbv = std::make_shared<BitCodeAbbrev>();
4299   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_EPOCH));
4300   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
4301   auto EpochAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4302   constexpr std::array<unsigned, 1> Vals = {{bitc::BITCODE_CURRENT_EPOCH}};
4303   Stream.EmitRecord(bitc::IDENTIFICATION_CODE_EPOCH, Vals, EpochAbbrev);
4304   Stream.ExitBlock();
4305 }
4306 
4307 void ModuleBitcodeWriter::writeModuleHash(size_t BlockStartPos) {
4308   // Emit the module's hash.
4309   // MODULE_CODE_HASH: [5*i32]
4310   if (GenerateHash) {
4311     uint32_t Vals[5];
4312     Hasher.update(ArrayRef<uint8_t>((const uint8_t *)&(Buffer)[BlockStartPos],
4313                                     Buffer.size() - BlockStartPos));
4314     StringRef Hash = Hasher.result();
4315     for (int Pos = 0; Pos < 20; Pos += 4) {
4316       Vals[Pos / 4] = support::endian::read32be(Hash.data() + Pos);
4317     }
4318 
4319     // Emit the finished record.
4320     Stream.EmitRecord(bitc::MODULE_CODE_HASH, Vals);
4321 
4322     if (ModHash)
4323       // Save the written hash value.
4324       llvm::copy(Vals, std::begin(*ModHash));
4325   }
4326 }
4327 
4328 void ModuleBitcodeWriter::write() {
4329   writeIdentificationBlock(Stream);
4330 
4331   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4332   size_t BlockStartPos = Buffer.size();
4333 
4334   writeModuleVersion();
4335 
4336   // Emit blockinfo, which defines the standard abbreviations etc.
4337   writeBlockInfo();
4338 
4339   // Emit information describing all of the types in the module.
4340   writeTypeTable();
4341 
4342   // Emit information about attribute groups.
4343   writeAttributeGroupTable();
4344 
4345   // Emit information about parameter attributes.
4346   writeAttributeTable();
4347 
4348   writeComdats();
4349 
4350   // Emit top-level description of module, including target triple, inline asm,
4351   // descriptors for global variables, and function prototype info.
4352   writeModuleInfo();
4353 
4354   // Emit constants.
4355   writeModuleConstants();
4356 
4357   // Emit metadata kind names.
4358   writeModuleMetadataKinds();
4359 
4360   // Emit metadata.
4361   writeModuleMetadata();
4362 
4363   // Emit module-level use-lists.
4364   if (VE.shouldPreserveUseListOrder())
4365     writeUseListBlock(nullptr);
4366 
4367   writeOperandBundleTags();
4368   writeSyncScopeNames();
4369 
4370   // Emit function bodies.
4371   DenseMap<const Function *, uint64_t> FunctionToBitcodeIndex;
4372   for (Module::const_iterator F = M.begin(), E = M.end(); F != E; ++F)
4373     if (!F->isDeclaration())
4374       writeFunction(*F, FunctionToBitcodeIndex);
4375 
4376   // Need to write after the above call to WriteFunction which populates
4377   // the summary information in the index.
4378   if (Index)
4379     writePerModuleGlobalValueSummary();
4380 
4381   writeGlobalValueSymbolTable(FunctionToBitcodeIndex);
4382 
4383   writeModuleHash(BlockStartPos);
4384 
4385   Stream.ExitBlock();
4386 }
4387 
4388 static void writeInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
4389                                uint32_t &Position) {
4390   support::endian::write32le(&Buffer[Position], Value);
4391   Position += 4;
4392 }
4393 
4394 /// If generating a bc file on darwin, we have to emit a
4395 /// header and trailer to make it compatible with the system archiver.  To do
4396 /// this we emit the following header, and then emit a trailer that pads the
4397 /// file out to be a multiple of 16 bytes.
4398 ///
4399 /// struct bc_header {
4400 ///   uint32_t Magic;         // 0x0B17C0DE
4401 ///   uint32_t Version;       // Version, currently always 0.
4402 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
4403 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
4404 ///   uint32_t CPUType;       // CPU specifier.
4405 ///   ... potentially more later ...
4406 /// };
4407 static void emitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
4408                                          const Triple &TT) {
4409   unsigned CPUType = ~0U;
4410 
4411   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
4412   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
4413   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
4414   // specific constants here because they are implicitly part of the Darwin ABI.
4415   enum {
4416     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
4417     DARWIN_CPU_TYPE_X86        = 7,
4418     DARWIN_CPU_TYPE_ARM        = 12,
4419     DARWIN_CPU_TYPE_POWERPC    = 18
4420   };
4421 
4422   Triple::ArchType Arch = TT.getArch();
4423   if (Arch == Triple::x86_64)
4424     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
4425   else if (Arch == Triple::x86)
4426     CPUType = DARWIN_CPU_TYPE_X86;
4427   else if (Arch == Triple::ppc)
4428     CPUType = DARWIN_CPU_TYPE_POWERPC;
4429   else if (Arch == Triple::ppc64)
4430     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
4431   else if (Arch == Triple::arm || Arch == Triple::thumb)
4432     CPUType = DARWIN_CPU_TYPE_ARM;
4433 
4434   // Traditional Bitcode starts after header.
4435   assert(Buffer.size() >= BWH_HeaderSize &&
4436          "Expected header size to be reserved");
4437   unsigned BCOffset = BWH_HeaderSize;
4438   unsigned BCSize = Buffer.size() - BWH_HeaderSize;
4439 
4440   // Write the magic and version.
4441   unsigned Position = 0;
4442   writeInt32ToBuffer(0x0B17C0DE, Buffer, Position);
4443   writeInt32ToBuffer(0, Buffer, Position); // Version.
4444   writeInt32ToBuffer(BCOffset, Buffer, Position);
4445   writeInt32ToBuffer(BCSize, Buffer, Position);
4446   writeInt32ToBuffer(CPUType, Buffer, Position);
4447 
4448   // If the file is not a multiple of 16 bytes, insert dummy padding.
4449   while (Buffer.size() & 15)
4450     Buffer.push_back(0);
4451 }
4452 
4453 /// Helper to write the header common to all bitcode files.
4454 static void writeBitcodeHeader(BitstreamWriter &Stream) {
4455   // Emit the file header.
4456   Stream.Emit((unsigned)'B', 8);
4457   Stream.Emit((unsigned)'C', 8);
4458   Stream.Emit(0x0, 4);
4459   Stream.Emit(0xC, 4);
4460   Stream.Emit(0xE, 4);
4461   Stream.Emit(0xD, 4);
4462 }
4463 
4464 BitcodeWriter::BitcodeWriter(SmallVectorImpl<char> &Buffer, raw_fd_stream *FS)
4465     : Buffer(Buffer), Stream(new BitstreamWriter(Buffer, FS, FlushThreshold)) {
4466   writeBitcodeHeader(*Stream);
4467 }
4468 
4469 BitcodeWriter::~BitcodeWriter() { assert(WroteStrtab); }
4470 
4471 void BitcodeWriter::writeBlob(unsigned Block, unsigned Record, StringRef Blob) {
4472   Stream->EnterSubblock(Block, 3);
4473 
4474   auto Abbv = std::make_shared<BitCodeAbbrev>();
4475   Abbv->Add(BitCodeAbbrevOp(Record));
4476   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
4477   auto AbbrevNo = Stream->EmitAbbrev(std::move(Abbv));
4478 
4479   Stream->EmitRecordWithBlob(AbbrevNo, ArrayRef<uint64_t>{Record}, Blob);
4480 
4481   Stream->ExitBlock();
4482 }
4483 
4484 void BitcodeWriter::writeSymtab() {
4485   assert(!WroteStrtab && !WroteSymtab);
4486 
4487   // If any module has module-level inline asm, we will require a registered asm
4488   // parser for the target so that we can create an accurate symbol table for
4489   // the module.
4490   for (Module *M : Mods) {
4491     if (M->getModuleInlineAsm().empty())
4492       continue;
4493 
4494     std::string Err;
4495     const Triple TT(M->getTargetTriple());
4496     const Target *T = TargetRegistry::lookupTarget(TT.str(), Err);
4497     if (!T || !T->hasMCAsmParser())
4498       return;
4499   }
4500 
4501   WroteSymtab = true;
4502   SmallVector<char, 0> Symtab;
4503   // The irsymtab::build function may be unable to create a symbol table if the
4504   // module is malformed (e.g. it contains an invalid alias). Writing a symbol
4505   // table is not required for correctness, but we still want to be able to
4506   // write malformed modules to bitcode files, so swallow the error.
4507   if (Error E = irsymtab::build(Mods, Symtab, StrtabBuilder, Alloc)) {
4508     consumeError(std::move(E));
4509     return;
4510   }
4511 
4512   writeBlob(bitc::SYMTAB_BLOCK_ID, bitc::SYMTAB_BLOB,
4513             {Symtab.data(), Symtab.size()});
4514 }
4515 
4516 void BitcodeWriter::writeStrtab() {
4517   assert(!WroteStrtab);
4518 
4519   std::vector<char> Strtab;
4520   StrtabBuilder.finalizeInOrder();
4521   Strtab.resize(StrtabBuilder.getSize());
4522   StrtabBuilder.write((uint8_t *)Strtab.data());
4523 
4524   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB,
4525             {Strtab.data(), Strtab.size()});
4526 
4527   WroteStrtab = true;
4528 }
4529 
4530 void BitcodeWriter::copyStrtab(StringRef Strtab) {
4531   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB, Strtab);
4532   WroteStrtab = true;
4533 }
4534 
4535 void BitcodeWriter::writeModule(const Module &M,
4536                                 bool ShouldPreserveUseListOrder,
4537                                 const ModuleSummaryIndex *Index,
4538                                 bool GenerateHash, ModuleHash *ModHash) {
4539   assert(!WroteStrtab);
4540 
4541   // The Mods vector is used by irsymtab::build, which requires non-const
4542   // Modules in case it needs to materialize metadata. But the bitcode writer
4543   // requires that the module is materialized, so we can cast to non-const here,
4544   // after checking that it is in fact materialized.
4545   assert(M.isMaterialized());
4546   Mods.push_back(const_cast<Module *>(&M));
4547 
4548   ModuleBitcodeWriter ModuleWriter(M, Buffer, StrtabBuilder, *Stream,
4549                                    ShouldPreserveUseListOrder, Index,
4550                                    GenerateHash, ModHash);
4551   ModuleWriter.write();
4552 }
4553 
4554 void BitcodeWriter::writeIndex(
4555     const ModuleSummaryIndex *Index,
4556     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4557   IndexBitcodeWriter IndexWriter(*Stream, StrtabBuilder, *Index,
4558                                  ModuleToSummariesForIndex);
4559   IndexWriter.write();
4560 }
4561 
4562 /// Write the specified module to the specified output stream.
4563 void llvm::WriteBitcodeToFile(const Module &M, raw_ostream &Out,
4564                               bool ShouldPreserveUseListOrder,
4565                               const ModuleSummaryIndex *Index,
4566                               bool GenerateHash, ModuleHash *ModHash) {
4567   SmallVector<char, 0> Buffer;
4568   Buffer.reserve(256*1024);
4569 
4570   // If this is darwin or another generic macho target, reserve space for the
4571   // header.
4572   Triple TT(M.getTargetTriple());
4573   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4574     Buffer.insert(Buffer.begin(), BWH_HeaderSize, 0);
4575 
4576   BitcodeWriter Writer(Buffer, dyn_cast<raw_fd_stream>(&Out));
4577   Writer.writeModule(M, ShouldPreserveUseListOrder, Index, GenerateHash,
4578                      ModHash);
4579   Writer.writeSymtab();
4580   Writer.writeStrtab();
4581 
4582   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4583     emitDarwinBCHeaderAndTrailer(Buffer, TT);
4584 
4585   // Write the generated bitstream to "Out".
4586   if (!Buffer.empty())
4587     Out.write((char *)&Buffer.front(), Buffer.size());
4588 }
4589 
4590 void IndexBitcodeWriter::write() {
4591   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4592 
4593   writeModuleVersion();
4594 
4595   // Write the module paths in the combined index.
4596   writeModStrings();
4597 
4598   // Write the summary combined index records.
4599   writeCombinedGlobalValueSummary();
4600 
4601   Stream.ExitBlock();
4602 }
4603 
4604 // Write the specified module summary index to the given raw output stream,
4605 // where it will be written in a new bitcode block. This is used when
4606 // writing the combined index file for ThinLTO. When writing a subset of the
4607 // index for a distributed backend, provide a \p ModuleToSummariesForIndex map.
4608 void llvm::WriteIndexToFile(
4609     const ModuleSummaryIndex &Index, raw_ostream &Out,
4610     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4611   SmallVector<char, 0> Buffer;
4612   Buffer.reserve(256 * 1024);
4613 
4614   BitcodeWriter Writer(Buffer);
4615   Writer.writeIndex(&Index, ModuleToSummariesForIndex);
4616   Writer.writeStrtab();
4617 
4618   Out.write((char *)&Buffer.front(), Buffer.size());
4619 }
4620 
4621 namespace {
4622 
4623 /// Class to manage the bitcode writing for a thin link bitcode file.
4624 class ThinLinkBitcodeWriter : public ModuleBitcodeWriterBase {
4625   /// ModHash is for use in ThinLTO incremental build, generated while writing
4626   /// the module bitcode file.
4627   const ModuleHash *ModHash;
4628 
4629 public:
4630   ThinLinkBitcodeWriter(const Module &M, StringTableBuilder &StrtabBuilder,
4631                         BitstreamWriter &Stream,
4632                         const ModuleSummaryIndex &Index,
4633                         const ModuleHash &ModHash)
4634       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
4635                                 /*ShouldPreserveUseListOrder=*/false, &Index),
4636         ModHash(&ModHash) {}
4637 
4638   void write();
4639 
4640 private:
4641   void writeSimplifiedModuleInfo();
4642 };
4643 
4644 } // end anonymous namespace
4645 
4646 // This function writes a simpilified module info for thin link bitcode file.
4647 // It only contains the source file name along with the name(the offset and
4648 // size in strtab) and linkage for global values. For the global value info
4649 // entry, in order to keep linkage at offset 5, there are three zeros used
4650 // as padding.
4651 void ThinLinkBitcodeWriter::writeSimplifiedModuleInfo() {
4652   SmallVector<unsigned, 64> Vals;
4653   // Emit the module's source file name.
4654   {
4655     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
4656     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
4657     if (Bits == SE_Char6)
4658       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
4659     else if (Bits == SE_Fixed7)
4660       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
4661 
4662     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
4663     auto Abbv = std::make_shared<BitCodeAbbrev>();
4664     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
4665     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4666     Abbv->Add(AbbrevOpToUse);
4667     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4668 
4669     for (const auto P : M.getSourceFileName())
4670       Vals.push_back((unsigned char)P);
4671 
4672     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
4673     Vals.clear();
4674   }
4675 
4676   // Emit the global variable information.
4677   for (const GlobalVariable &GV : M.globals()) {
4678     // GLOBALVAR: [strtab offset, strtab size, 0, 0, 0, linkage]
4679     Vals.push_back(StrtabBuilder.add(GV.getName()));
4680     Vals.push_back(GV.getName().size());
4681     Vals.push_back(0);
4682     Vals.push_back(0);
4683     Vals.push_back(0);
4684     Vals.push_back(getEncodedLinkage(GV));
4685 
4686     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals);
4687     Vals.clear();
4688   }
4689 
4690   // Emit the function proto information.
4691   for (const Function &F : M) {
4692     // FUNCTION:  [strtab offset, strtab size, 0, 0, 0, linkage]
4693     Vals.push_back(StrtabBuilder.add(F.getName()));
4694     Vals.push_back(F.getName().size());
4695     Vals.push_back(0);
4696     Vals.push_back(0);
4697     Vals.push_back(0);
4698     Vals.push_back(getEncodedLinkage(F));
4699 
4700     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals);
4701     Vals.clear();
4702   }
4703 
4704   // Emit the alias information.
4705   for (const GlobalAlias &A : M.aliases()) {
4706     // ALIAS: [strtab offset, strtab size, 0, 0, 0, linkage]
4707     Vals.push_back(StrtabBuilder.add(A.getName()));
4708     Vals.push_back(A.getName().size());
4709     Vals.push_back(0);
4710     Vals.push_back(0);
4711     Vals.push_back(0);
4712     Vals.push_back(getEncodedLinkage(A));
4713 
4714     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals);
4715     Vals.clear();
4716   }
4717 
4718   // Emit the ifunc information.
4719   for (const GlobalIFunc &I : M.ifuncs()) {
4720     // IFUNC: [strtab offset, strtab size, 0, 0, 0, linkage]
4721     Vals.push_back(StrtabBuilder.add(I.getName()));
4722     Vals.push_back(I.getName().size());
4723     Vals.push_back(0);
4724     Vals.push_back(0);
4725     Vals.push_back(0);
4726     Vals.push_back(getEncodedLinkage(I));
4727 
4728     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
4729     Vals.clear();
4730   }
4731 }
4732 
4733 void ThinLinkBitcodeWriter::write() {
4734   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4735 
4736   writeModuleVersion();
4737 
4738   writeSimplifiedModuleInfo();
4739 
4740   writePerModuleGlobalValueSummary();
4741 
4742   // Write module hash.
4743   Stream.EmitRecord(bitc::MODULE_CODE_HASH, ArrayRef<uint32_t>(*ModHash));
4744 
4745   Stream.ExitBlock();
4746 }
4747 
4748 void BitcodeWriter::writeThinLinkBitcode(const Module &M,
4749                                          const ModuleSummaryIndex &Index,
4750                                          const ModuleHash &ModHash) {
4751   assert(!WroteStrtab);
4752 
4753   // The Mods vector is used by irsymtab::build, which requires non-const
4754   // Modules in case it needs to materialize metadata. But the bitcode writer
4755   // requires that the module is materialized, so we can cast to non-const here,
4756   // after checking that it is in fact materialized.
4757   assert(M.isMaterialized());
4758   Mods.push_back(const_cast<Module *>(&M));
4759 
4760   ThinLinkBitcodeWriter ThinLinkWriter(M, StrtabBuilder, *Stream, Index,
4761                                        ModHash);
4762   ThinLinkWriter.write();
4763 }
4764 
4765 // Write the specified thin link bitcode file to the given raw output stream,
4766 // where it will be written in a new bitcode block. This is used when
4767 // writing the per-module index file for ThinLTO.
4768 void llvm::WriteThinLinkBitcodeToFile(const Module &M, raw_ostream &Out,
4769                                       const ModuleSummaryIndex &Index,
4770                                       const ModuleHash &ModHash) {
4771   SmallVector<char, 0> Buffer;
4772   Buffer.reserve(256 * 1024);
4773 
4774   BitcodeWriter Writer(Buffer);
4775   Writer.writeThinLinkBitcode(M, Index, ModHash);
4776   Writer.writeSymtab();
4777   Writer.writeStrtab();
4778 
4779   Out.write((char *)&Buffer.front(), Buffer.size());
4780 }
4781 
4782 static const char *getSectionNameForBitcode(const Triple &T) {
4783   switch (T.getObjectFormat()) {
4784   case Triple::MachO:
4785     return "__LLVM,__bitcode";
4786   case Triple::COFF:
4787   case Triple::ELF:
4788   case Triple::Wasm:
4789   case Triple::UnknownObjectFormat:
4790     return ".llvmbc";
4791   case Triple::GOFF:
4792     llvm_unreachable("GOFF is not yet implemented");
4793     break;
4794   case Triple::XCOFF:
4795     llvm_unreachable("XCOFF is not yet implemented");
4796     break;
4797   }
4798   llvm_unreachable("Unimplemented ObjectFormatType");
4799 }
4800 
4801 static const char *getSectionNameForCommandline(const Triple &T) {
4802   switch (T.getObjectFormat()) {
4803   case Triple::MachO:
4804     return "__LLVM,__cmdline";
4805   case Triple::COFF:
4806   case Triple::ELF:
4807   case Triple::Wasm:
4808   case Triple::UnknownObjectFormat:
4809     return ".llvmcmd";
4810   case Triple::GOFF:
4811     llvm_unreachable("GOFF is not yet implemented");
4812     break;
4813   case Triple::XCOFF:
4814     llvm_unreachable("XCOFF is not yet implemented");
4815     break;
4816   }
4817   llvm_unreachable("Unimplemented ObjectFormatType");
4818 }
4819 
4820 void llvm::EmbedBitcodeInModule(llvm::Module &M, llvm::MemoryBufferRef Buf,
4821                                 bool EmbedBitcode, bool EmbedMarker,
4822                                 const std::vector<uint8_t> &CmdArgs) {
4823   // Save llvm.compiler.used and remove it.
4824   SmallVector<Constant *, 2> UsedArray;
4825   SmallPtrSet<GlobalValue *, 4> UsedGlobals;
4826   Type *UsedElementType = Type::getInt8Ty(M.getContext())->getPointerTo(0);
4827   GlobalVariable *Used = collectUsedGlobalVariables(M, UsedGlobals, true);
4828   for (auto *GV : UsedGlobals) {
4829     if (GV->getName() != "llvm.embedded.module" &&
4830         GV->getName() != "llvm.cmdline")
4831       UsedArray.push_back(
4832           ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
4833   }
4834   if (Used)
4835     Used->eraseFromParent();
4836 
4837   // Embed the bitcode for the llvm module.
4838   std::string Data;
4839   ArrayRef<uint8_t> ModuleData;
4840   Triple T(M.getTargetTriple());
4841 
4842   if (EmbedBitcode) {
4843     if (Buf.getBufferSize() == 0 ||
4844         !isBitcode((const unsigned char *)Buf.getBufferStart(),
4845                    (const unsigned char *)Buf.getBufferEnd())) {
4846       // If the input is LLVM Assembly, bitcode is produced by serializing
4847       // the module. Use-lists order need to be preserved in this case.
4848       llvm::raw_string_ostream OS(Data);
4849       llvm::WriteBitcodeToFile(M, OS, /* ShouldPreserveUseListOrder */ true);
4850       ModuleData =
4851           ArrayRef<uint8_t>((const uint8_t *)OS.str().data(), OS.str().size());
4852     } else
4853       // If the input is LLVM bitcode, write the input byte stream directly.
4854       ModuleData = ArrayRef<uint8_t>((const uint8_t *)Buf.getBufferStart(),
4855                                      Buf.getBufferSize());
4856   }
4857   llvm::Constant *ModuleConstant =
4858       llvm::ConstantDataArray::get(M.getContext(), ModuleData);
4859   llvm::GlobalVariable *GV = new llvm::GlobalVariable(
4860       M, ModuleConstant->getType(), true, llvm::GlobalValue::PrivateLinkage,
4861       ModuleConstant);
4862   GV->setSection(getSectionNameForBitcode(T));
4863   // Set alignment to 1 to prevent padding between two contributions from input
4864   // sections after linking.
4865   GV->setAlignment(Align(1));
4866   UsedArray.push_back(
4867       ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
4868   if (llvm::GlobalVariable *Old =
4869           M.getGlobalVariable("llvm.embedded.module", true)) {
4870     assert(Old->hasOneUse() &&
4871            "llvm.embedded.module can only be used once in llvm.compiler.used");
4872     GV->takeName(Old);
4873     Old->eraseFromParent();
4874   } else {
4875     GV->setName("llvm.embedded.module");
4876   }
4877 
4878   // Skip if only bitcode needs to be embedded.
4879   if (EmbedMarker) {
4880     // Embed command-line options.
4881     ArrayRef<uint8_t> CmdData(const_cast<uint8_t *>(CmdArgs.data()),
4882                               CmdArgs.size());
4883     llvm::Constant *CmdConstant =
4884         llvm::ConstantDataArray::get(M.getContext(), CmdData);
4885     GV = new llvm::GlobalVariable(M, CmdConstant->getType(), true,
4886                                   llvm::GlobalValue::PrivateLinkage,
4887                                   CmdConstant);
4888     GV->setSection(getSectionNameForCommandline(T));
4889     GV->setAlignment(Align(1));
4890     UsedArray.push_back(
4891         ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
4892     if (llvm::GlobalVariable *Old = M.getGlobalVariable("llvm.cmdline", true)) {
4893       assert(Old->hasOneUse() &&
4894              "llvm.cmdline can only be used once in llvm.compiler.used");
4895       GV->takeName(Old);
4896       Old->eraseFromParent();
4897     } else {
4898       GV->setName("llvm.cmdline");
4899     }
4900   }
4901 
4902   if (UsedArray.empty())
4903     return;
4904 
4905   // Recreate llvm.compiler.used.
4906   ArrayType *ATy = ArrayType::get(UsedElementType, UsedArray.size());
4907   auto *NewUsed = new GlobalVariable(
4908       M, ATy, false, llvm::GlobalValue::AppendingLinkage,
4909       llvm::ConstantArray::get(ATy, UsedArray), "llvm.compiler.used");
4910   NewUsed->setSection("llvm.metadata");
4911 }
4912