xref: /llvm-project/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp (revision a907d36cfe8069ce191ffada3b84e37ca50e05b6)
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/SmallPtrSet.h"
23 #include "llvm/ADT/SmallString.h"
24 #include "llvm/ADT/SmallVector.h"
25 #include "llvm/ADT/StringMap.h"
26 #include "llvm/ADT/StringRef.h"
27 #include "llvm/ADT/Triple.h"
28 #include "llvm/Bitcode/BitcodeCommon.h"
29 #include "llvm/Bitcode/BitcodeReader.h"
30 #include "llvm/Bitcode/LLVMBitCodes.h"
31 #include "llvm/Bitstream/BitCodes.h"
32 #include "llvm/Bitstream/BitstreamWriter.h"
33 #include "llvm/Config/llvm-config.h"
34 #include "llvm/IR/Attributes.h"
35 #include "llvm/IR/BasicBlock.h"
36 #include "llvm/IR/Comdat.h"
37 #include "llvm/IR/Constant.h"
38 #include "llvm/IR/Constants.h"
39 #include "llvm/IR/DebugInfoMetadata.h"
40 #include "llvm/IR/DebugLoc.h"
41 #include "llvm/IR/DerivedTypes.h"
42 #include "llvm/IR/Function.h"
43 #include "llvm/IR/GlobalAlias.h"
44 #include "llvm/IR/GlobalIFunc.h"
45 #include "llvm/IR/GlobalObject.h"
46 #include "llvm/IR/GlobalValue.h"
47 #include "llvm/IR/GlobalVariable.h"
48 #include "llvm/IR/InlineAsm.h"
49 #include "llvm/IR/InstrTypes.h"
50 #include "llvm/IR/Instruction.h"
51 #include "llvm/IR/Instructions.h"
52 #include "llvm/IR/LLVMContext.h"
53 #include "llvm/IR/Metadata.h"
54 #include "llvm/IR/Module.h"
55 #include "llvm/IR/ModuleSummaryIndex.h"
56 #include "llvm/IR/Operator.h"
57 #include "llvm/IR/Type.h"
58 #include "llvm/IR/UseListOrder.h"
59 #include "llvm/IR/Value.h"
60 #include "llvm/IR/ValueSymbolTable.h"
61 #include "llvm/MC/StringTableBuilder.h"
62 #include "llvm/MC/TargetRegistry.h"
63 #include "llvm/Object/IRSymtab.h"
64 #include "llvm/Support/AtomicOrdering.h"
65 #include "llvm/Support/Casting.h"
66 #include "llvm/Support/CommandLine.h"
67 #include "llvm/Support/Endian.h"
68 #include "llvm/Support/Error.h"
69 #include "llvm/Support/ErrorHandling.h"
70 #include "llvm/Support/MathExtras.h"
71 #include "llvm/Support/SHA1.h"
72 #include "llvm/Support/raw_ostream.h"
73 #include <algorithm>
74 #include <cassert>
75 #include <cstddef>
76 #include <cstdint>
77 #include <iterator>
78 #include <map>
79 #include <memory>
80 #include <string>
81 #include <utility>
82 #include <vector>
83 
84 using namespace llvm;
85 
86 static cl::opt<unsigned>
87     IndexThreshold("bitcode-mdindex-threshold", cl::Hidden, cl::init(25),
88                    cl::desc("Number of metadatas above which we emit an index "
89                             "to enable lazy-loading"));
90 static cl::opt<uint32_t> FlushThreshold(
91     "bitcode-flush-threshold", cl::Hidden, cl::init(512),
92     cl::desc("The threshold (unit M) for flushing LLVM bitcode."));
93 
94 static cl::opt<bool> WriteRelBFToSummary(
95     "write-relbf-to-summary", cl::Hidden, cl::init(false),
96     cl::desc("Write relative block frequency to function summary "));
97 
98 extern FunctionSummary::ForceSummaryHotnessType ForceSummaryEdgesCold;
99 
100 namespace {
101 
102 /// These are manifest constants used by the bitcode writer. They do not need to
103 /// be kept in sync with the reader, but need to be consistent within this file.
104 enum {
105   // VALUE_SYMTAB_BLOCK abbrev id's.
106   VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
107   VST_ENTRY_7_ABBREV,
108   VST_ENTRY_6_ABBREV,
109   VST_BBENTRY_6_ABBREV,
110 
111   // CONSTANTS_BLOCK abbrev id's.
112   CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
113   CONSTANTS_INTEGER_ABBREV,
114   CONSTANTS_CE_CAST_Abbrev,
115   CONSTANTS_NULL_Abbrev,
116 
117   // FUNCTION_BLOCK abbrev id's.
118   FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
119   FUNCTION_INST_UNOP_ABBREV,
120   FUNCTION_INST_UNOP_FLAGS_ABBREV,
121   FUNCTION_INST_BINOP_ABBREV,
122   FUNCTION_INST_BINOP_FLAGS_ABBREV,
123   FUNCTION_INST_CAST_ABBREV,
124   FUNCTION_INST_RET_VOID_ABBREV,
125   FUNCTION_INST_RET_VAL_ABBREV,
126   FUNCTION_INST_UNREACHABLE_ABBREV,
127   FUNCTION_INST_GEP_ABBREV,
128 };
129 
130 /// Abstract class to manage the bitcode writing, subclassed for each bitcode
131 /// file type.
132 class BitcodeWriterBase {
133 protected:
134   /// The stream created and owned by the client.
135   BitstreamWriter &Stream;
136 
137   StringTableBuilder &StrtabBuilder;
138 
139 public:
140   /// Constructs a BitcodeWriterBase object that writes to the provided
141   /// \p Stream.
142   BitcodeWriterBase(BitstreamWriter &Stream, StringTableBuilder &StrtabBuilder)
143       : Stream(Stream), StrtabBuilder(StrtabBuilder) {}
144 
145 protected:
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 writeDIGenericSubrange(const DIGenericSubrange *N,
304                               SmallVectorImpl<uint64_t> &Record,
305                               unsigned Abbrev);
306   void writeDIEnumerator(const DIEnumerator *N,
307                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
308   void writeDIBasicType(const DIBasicType *N, SmallVectorImpl<uint64_t> &Record,
309                         unsigned Abbrev);
310   void writeDIStringType(const DIStringType *N,
311                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
312   void writeDIDerivedType(const DIDerivedType *N,
313                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
314   void writeDICompositeType(const DICompositeType *N,
315                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
316   void writeDISubroutineType(const DISubroutineType *N,
317                              SmallVectorImpl<uint64_t> &Record,
318                              unsigned Abbrev);
319   void writeDIFile(const DIFile *N, SmallVectorImpl<uint64_t> &Record,
320                    unsigned Abbrev);
321   void writeDICompileUnit(const DICompileUnit *N,
322                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
323   void writeDISubprogram(const DISubprogram *N,
324                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
325   void writeDILexicalBlock(const DILexicalBlock *N,
326                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
327   void writeDILexicalBlockFile(const DILexicalBlockFile *N,
328                                SmallVectorImpl<uint64_t> &Record,
329                                unsigned Abbrev);
330   void writeDICommonBlock(const DICommonBlock *N,
331                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
332   void writeDINamespace(const DINamespace *N, SmallVectorImpl<uint64_t> &Record,
333                         unsigned Abbrev);
334   void writeDIMacro(const DIMacro *N, SmallVectorImpl<uint64_t> &Record,
335                     unsigned Abbrev);
336   void writeDIMacroFile(const DIMacroFile *N, SmallVectorImpl<uint64_t> &Record,
337                         unsigned Abbrev);
338   void writeDIArgList(const DIArgList *N, SmallVectorImpl<uint64_t> &Record,
339                       unsigned Abbrev);
340   void writeDIModule(const DIModule *N, SmallVectorImpl<uint64_t> &Record,
341                      unsigned Abbrev);
342   void writeDITemplateTypeParameter(const DITemplateTypeParameter *N,
343                                     SmallVectorImpl<uint64_t> &Record,
344                                     unsigned Abbrev);
345   void writeDITemplateValueParameter(const DITemplateValueParameter *N,
346                                      SmallVectorImpl<uint64_t> &Record,
347                                      unsigned Abbrev);
348   void writeDIGlobalVariable(const DIGlobalVariable *N,
349                              SmallVectorImpl<uint64_t> &Record,
350                              unsigned Abbrev);
351   void writeDILocalVariable(const DILocalVariable *N,
352                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
353   void writeDILabel(const DILabel *N,
354                     SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
355   void writeDIExpression(const DIExpression *N,
356                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
357   void writeDIGlobalVariableExpression(const DIGlobalVariableExpression *N,
358                                        SmallVectorImpl<uint64_t> &Record,
359                                        unsigned Abbrev);
360   void writeDIObjCProperty(const DIObjCProperty *N,
361                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
362   void writeDIImportedEntity(const DIImportedEntity *N,
363                              SmallVectorImpl<uint64_t> &Record,
364                              unsigned Abbrev);
365   unsigned createNamedMetadataAbbrev();
366   void writeNamedMetadata(SmallVectorImpl<uint64_t> &Record);
367   unsigned createMetadataStringsAbbrev();
368   void writeMetadataStrings(ArrayRef<const Metadata *> Strings,
369                             SmallVectorImpl<uint64_t> &Record);
370   void writeMetadataRecords(ArrayRef<const Metadata *> MDs,
371                             SmallVectorImpl<uint64_t> &Record,
372                             std::vector<unsigned> *MDAbbrevs = nullptr,
373                             std::vector<uint64_t> *IndexPos = nullptr);
374   void writeModuleMetadata();
375   void writeFunctionMetadata(const Function &F);
376   void writeFunctionMetadataAttachment(const Function &F);
377   void pushGlobalMetadataAttachment(SmallVectorImpl<uint64_t> &Record,
378                                     const GlobalObject &GO);
379   void writeModuleMetadataKinds();
380   void writeOperandBundleTags();
381   void writeSyncScopeNames();
382   void writeConstants(unsigned FirstVal, unsigned LastVal, bool isGlobal);
383   void writeModuleConstants();
384   bool pushValueAndType(const Value *V, unsigned InstID,
385                         SmallVectorImpl<unsigned> &Vals);
386   void writeOperandBundles(const CallBase &CB, unsigned InstID);
387   void pushValue(const Value *V, unsigned InstID,
388                  SmallVectorImpl<unsigned> &Vals);
389   void pushValueSigned(const Value *V, unsigned InstID,
390                        SmallVectorImpl<uint64_t> &Vals);
391   void writeInstruction(const Instruction &I, unsigned InstID,
392                         SmallVectorImpl<unsigned> &Vals);
393   void writeFunctionLevelValueSymbolTable(const ValueSymbolTable &VST);
394   void writeGlobalValueSymbolTable(
395       DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
396   void writeUseList(UseListOrder &&Order);
397   void writeUseListBlock(const Function *F);
398   void
399   writeFunction(const Function &F,
400                 DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
401   void writeBlockInfo();
402   void writeModuleHash(size_t BlockStartPos);
403 
404   unsigned getEncodedSyncScopeID(SyncScope::ID SSID) {
405     return unsigned(SSID);
406   }
407 
408   unsigned getEncodedAlign(MaybeAlign Alignment) { return encode(Alignment); }
409 };
410 
411 /// Class to manage the bitcode writing for a combined index.
412 class IndexBitcodeWriter : public BitcodeWriterBase {
413   /// The combined index to write to bitcode.
414   const ModuleSummaryIndex &Index;
415 
416   /// When writing a subset of the index for distributed backends, client
417   /// provides a map of modules to the corresponding GUIDs/summaries to write.
418   const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex;
419 
420   /// Map that holds the correspondence between the GUID used in the combined
421   /// index and a value id generated by this class to use in references.
422   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
423 
424   /// Tracks the last value id recorded in the GUIDToValueMap.
425   unsigned GlobalValueId = 0;
426 
427 public:
428   /// Constructs a IndexBitcodeWriter object for the given combined index,
429   /// writing to the provided \p Buffer. When writing a subset of the index
430   /// for a distributed backend, provide a \p ModuleToSummariesForIndex map.
431   IndexBitcodeWriter(BitstreamWriter &Stream, StringTableBuilder &StrtabBuilder,
432                      const ModuleSummaryIndex &Index,
433                      const std::map<std::string, GVSummaryMapTy>
434                          *ModuleToSummariesForIndex = nullptr)
435       : BitcodeWriterBase(Stream, StrtabBuilder), Index(Index),
436         ModuleToSummariesForIndex(ModuleToSummariesForIndex) {
437     // Assign unique value ids to all summaries to be written, for use
438     // in writing out the call graph edges. Save the mapping from GUID
439     // to the new global value id to use when writing those edges, which
440     // are currently saved in the index in terms of GUID.
441     forEachSummary([&](GVInfo I, bool) {
442       GUIDToValueIdMap[I.first] = ++GlobalValueId;
443     });
444   }
445 
446   /// The below iterator returns the GUID and associated summary.
447   using GVInfo = std::pair<GlobalValue::GUID, GlobalValueSummary *>;
448 
449   /// Calls the callback for each value GUID and summary to be written to
450   /// bitcode. This hides the details of whether they are being pulled from the
451   /// entire index or just those in a provided ModuleToSummariesForIndex map.
452   template<typename Functor>
453   void forEachSummary(Functor Callback) {
454     if (ModuleToSummariesForIndex) {
455       for (auto &M : *ModuleToSummariesForIndex)
456         for (auto &Summary : M.second) {
457           Callback(Summary, false);
458           // Ensure aliasee is handled, e.g. for assigning a valueId,
459           // even if we are not importing the aliasee directly (the
460           // imported alias will contain a copy of aliasee).
461           if (auto *AS = dyn_cast<AliasSummary>(Summary.getSecond()))
462             Callback({AS->getAliaseeGUID(), &AS->getAliasee()}, true);
463         }
464     } else {
465       for (auto &Summaries : Index)
466         for (auto &Summary : Summaries.second.SummaryList)
467           Callback({Summaries.first, Summary.get()}, false);
468     }
469   }
470 
471   /// Calls the callback for each entry in the modulePaths StringMap that
472   /// should be written to the module path string table. This hides the details
473   /// of whether they are being pulled from the entire index or just those in a
474   /// provided ModuleToSummariesForIndex map.
475   template <typename Functor> void forEachModule(Functor Callback) {
476     if (ModuleToSummariesForIndex) {
477       for (const auto &M : *ModuleToSummariesForIndex) {
478         const auto &MPI = Index.modulePaths().find(M.first);
479         if (MPI == Index.modulePaths().end()) {
480           // This should only happen if the bitcode file was empty, in which
481           // case we shouldn't be importing (the ModuleToSummariesForIndex
482           // would only include the module we are writing and index for).
483           assert(ModuleToSummariesForIndex->size() == 1);
484           continue;
485         }
486         Callback(*MPI);
487       }
488     } else {
489       for (const auto &MPSE : Index.modulePaths())
490         Callback(MPSE);
491     }
492   }
493 
494   /// Main entry point for writing a combined index to bitcode.
495   void write();
496 
497 private:
498   void writeModStrings();
499   void writeCombinedGlobalValueSummary();
500 
501   Optional<unsigned> getValueId(GlobalValue::GUID ValGUID) {
502     auto VMI = GUIDToValueIdMap.find(ValGUID);
503     if (VMI == GUIDToValueIdMap.end())
504       return None;
505     return VMI->second;
506   }
507 
508   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
509 };
510 
511 } // end anonymous namespace
512 
513 static unsigned getEncodedCastOpcode(unsigned Opcode) {
514   switch (Opcode) {
515   default: llvm_unreachable("Unknown cast instruction!");
516   case Instruction::Trunc   : return bitc::CAST_TRUNC;
517   case Instruction::ZExt    : return bitc::CAST_ZEXT;
518   case Instruction::SExt    : return bitc::CAST_SEXT;
519   case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
520   case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
521   case Instruction::UIToFP  : return bitc::CAST_UITOFP;
522   case Instruction::SIToFP  : return bitc::CAST_SITOFP;
523   case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
524   case Instruction::FPExt   : return bitc::CAST_FPEXT;
525   case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
526   case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
527   case Instruction::BitCast : return bitc::CAST_BITCAST;
528   case Instruction::AddrSpaceCast: return bitc::CAST_ADDRSPACECAST;
529   }
530 }
531 
532 static unsigned getEncodedUnaryOpcode(unsigned Opcode) {
533   switch (Opcode) {
534   default: llvm_unreachable("Unknown binary instruction!");
535   case Instruction::FNeg: return bitc::UNOP_FNEG;
536   }
537 }
538 
539 static unsigned getEncodedBinaryOpcode(unsigned Opcode) {
540   switch (Opcode) {
541   default: llvm_unreachable("Unknown binary instruction!");
542   case Instruction::Add:
543   case Instruction::FAdd: return bitc::BINOP_ADD;
544   case Instruction::Sub:
545   case Instruction::FSub: return bitc::BINOP_SUB;
546   case Instruction::Mul:
547   case Instruction::FMul: return bitc::BINOP_MUL;
548   case Instruction::UDiv: return bitc::BINOP_UDIV;
549   case Instruction::FDiv:
550   case Instruction::SDiv: return bitc::BINOP_SDIV;
551   case Instruction::URem: return bitc::BINOP_UREM;
552   case Instruction::FRem:
553   case Instruction::SRem: return bitc::BINOP_SREM;
554   case Instruction::Shl:  return bitc::BINOP_SHL;
555   case Instruction::LShr: return bitc::BINOP_LSHR;
556   case Instruction::AShr: return bitc::BINOP_ASHR;
557   case Instruction::And:  return bitc::BINOP_AND;
558   case Instruction::Or:   return bitc::BINOP_OR;
559   case Instruction::Xor:  return bitc::BINOP_XOR;
560   }
561 }
562 
563 static unsigned getEncodedRMWOperation(AtomicRMWInst::BinOp Op) {
564   switch (Op) {
565   default: llvm_unreachable("Unknown RMW operation!");
566   case AtomicRMWInst::Xchg: return bitc::RMW_XCHG;
567   case AtomicRMWInst::Add: return bitc::RMW_ADD;
568   case AtomicRMWInst::Sub: return bitc::RMW_SUB;
569   case AtomicRMWInst::And: return bitc::RMW_AND;
570   case AtomicRMWInst::Nand: return bitc::RMW_NAND;
571   case AtomicRMWInst::Or: return bitc::RMW_OR;
572   case AtomicRMWInst::Xor: return bitc::RMW_XOR;
573   case AtomicRMWInst::Max: return bitc::RMW_MAX;
574   case AtomicRMWInst::Min: return bitc::RMW_MIN;
575   case AtomicRMWInst::UMax: return bitc::RMW_UMAX;
576   case AtomicRMWInst::UMin: return bitc::RMW_UMIN;
577   case AtomicRMWInst::FAdd: return bitc::RMW_FADD;
578   case AtomicRMWInst::FSub: return bitc::RMW_FSUB;
579   }
580 }
581 
582 static unsigned getEncodedOrdering(AtomicOrdering Ordering) {
583   switch (Ordering) {
584   case AtomicOrdering::NotAtomic: return bitc::ORDERING_NOTATOMIC;
585   case AtomicOrdering::Unordered: return bitc::ORDERING_UNORDERED;
586   case AtomicOrdering::Monotonic: return bitc::ORDERING_MONOTONIC;
587   case AtomicOrdering::Acquire: return bitc::ORDERING_ACQUIRE;
588   case AtomicOrdering::Release: return bitc::ORDERING_RELEASE;
589   case AtomicOrdering::AcquireRelease: return bitc::ORDERING_ACQREL;
590   case AtomicOrdering::SequentiallyConsistent: return bitc::ORDERING_SEQCST;
591   }
592   llvm_unreachable("Invalid ordering");
593 }
594 
595 static void writeStringRecord(BitstreamWriter &Stream, unsigned Code,
596                               StringRef Str, unsigned AbbrevToUse) {
597   SmallVector<unsigned, 64> Vals;
598 
599   // Code: [strchar x N]
600   for (char C : Str) {
601     if (AbbrevToUse && !BitCodeAbbrevOp::isChar6(C))
602       AbbrevToUse = 0;
603     Vals.push_back(C);
604   }
605 
606   // Emit the finished record.
607   Stream.EmitRecord(Code, Vals, AbbrevToUse);
608 }
609 
610 static uint64_t getAttrKindEncoding(Attribute::AttrKind Kind) {
611   switch (Kind) {
612   case Attribute::Alignment:
613     return bitc::ATTR_KIND_ALIGNMENT;
614   case Attribute::AllocAlign:
615     return bitc::ATTR_KIND_ALLOC_ALIGN;
616   case Attribute::AllocSize:
617     return bitc::ATTR_KIND_ALLOC_SIZE;
618   case Attribute::AlwaysInline:
619     return bitc::ATTR_KIND_ALWAYS_INLINE;
620   case Attribute::ArgMemOnly:
621     return bitc::ATTR_KIND_ARGMEMONLY;
622   case Attribute::Builtin:
623     return bitc::ATTR_KIND_BUILTIN;
624   case Attribute::ByVal:
625     return bitc::ATTR_KIND_BY_VAL;
626   case Attribute::Convergent:
627     return bitc::ATTR_KIND_CONVERGENT;
628   case Attribute::InAlloca:
629     return bitc::ATTR_KIND_IN_ALLOCA;
630   case Attribute::Cold:
631     return bitc::ATTR_KIND_COLD;
632   case Attribute::DisableSanitizerInstrumentation:
633     return bitc::ATTR_KIND_DISABLE_SANITIZER_INSTRUMENTATION;
634   case Attribute::Hot:
635     return bitc::ATTR_KIND_HOT;
636   case Attribute::ElementType:
637     return bitc::ATTR_KIND_ELEMENTTYPE;
638   case Attribute::InaccessibleMemOnly:
639     return bitc::ATTR_KIND_INACCESSIBLEMEM_ONLY;
640   case Attribute::InaccessibleMemOrArgMemOnly:
641     return bitc::ATTR_KIND_INACCESSIBLEMEM_OR_ARGMEMONLY;
642   case Attribute::InlineHint:
643     return bitc::ATTR_KIND_INLINE_HINT;
644   case Attribute::InReg:
645     return bitc::ATTR_KIND_IN_REG;
646   case Attribute::JumpTable:
647     return bitc::ATTR_KIND_JUMP_TABLE;
648   case Attribute::MinSize:
649     return bitc::ATTR_KIND_MIN_SIZE;
650   case Attribute::AllocatedPointer:
651     return bitc::ATTR_KIND_ALLOCATED_POINTER;
652   case Attribute::Naked:
653     return bitc::ATTR_KIND_NAKED;
654   case Attribute::Nest:
655     return bitc::ATTR_KIND_NEST;
656   case Attribute::NoAlias:
657     return bitc::ATTR_KIND_NO_ALIAS;
658   case Attribute::NoBuiltin:
659     return bitc::ATTR_KIND_NO_BUILTIN;
660   case Attribute::NoCallback:
661     return bitc::ATTR_KIND_NO_CALLBACK;
662   case Attribute::NoCapture:
663     return bitc::ATTR_KIND_NO_CAPTURE;
664   case Attribute::NoDuplicate:
665     return bitc::ATTR_KIND_NO_DUPLICATE;
666   case Attribute::NoFree:
667     return bitc::ATTR_KIND_NOFREE;
668   case Attribute::NoImplicitFloat:
669     return bitc::ATTR_KIND_NO_IMPLICIT_FLOAT;
670   case Attribute::NoInline:
671     return bitc::ATTR_KIND_NO_INLINE;
672   case Attribute::NoRecurse:
673     return bitc::ATTR_KIND_NO_RECURSE;
674   case Attribute::NoMerge:
675     return bitc::ATTR_KIND_NO_MERGE;
676   case Attribute::NonLazyBind:
677     return bitc::ATTR_KIND_NON_LAZY_BIND;
678   case Attribute::NonNull:
679     return bitc::ATTR_KIND_NON_NULL;
680   case Attribute::Dereferenceable:
681     return bitc::ATTR_KIND_DEREFERENCEABLE;
682   case Attribute::DereferenceableOrNull:
683     return bitc::ATTR_KIND_DEREFERENCEABLE_OR_NULL;
684   case Attribute::NoRedZone:
685     return bitc::ATTR_KIND_NO_RED_ZONE;
686   case Attribute::NoReturn:
687     return bitc::ATTR_KIND_NO_RETURN;
688   case Attribute::NoSync:
689     return bitc::ATTR_KIND_NOSYNC;
690   case Attribute::NoCfCheck:
691     return bitc::ATTR_KIND_NOCF_CHECK;
692   case Attribute::NoProfile:
693     return bitc::ATTR_KIND_NO_PROFILE;
694   case Attribute::NoUnwind:
695     return bitc::ATTR_KIND_NO_UNWIND;
696   case Attribute::NoSanitizeBounds:
697     return bitc::ATTR_KIND_NO_SANITIZE_BOUNDS;
698   case Attribute::NoSanitizeCoverage:
699     return bitc::ATTR_KIND_NO_SANITIZE_COVERAGE;
700   case Attribute::NullPointerIsValid:
701     return bitc::ATTR_KIND_NULL_POINTER_IS_VALID;
702   case Attribute::OptForFuzzing:
703     return bitc::ATTR_KIND_OPT_FOR_FUZZING;
704   case Attribute::OptimizeForSize:
705     return bitc::ATTR_KIND_OPTIMIZE_FOR_SIZE;
706   case Attribute::OptimizeNone:
707     return bitc::ATTR_KIND_OPTIMIZE_NONE;
708   case Attribute::ReadNone:
709     return bitc::ATTR_KIND_READ_NONE;
710   case Attribute::ReadOnly:
711     return bitc::ATTR_KIND_READ_ONLY;
712   case Attribute::Returned:
713     return bitc::ATTR_KIND_RETURNED;
714   case Attribute::ReturnsTwice:
715     return bitc::ATTR_KIND_RETURNS_TWICE;
716   case Attribute::SExt:
717     return bitc::ATTR_KIND_S_EXT;
718   case Attribute::Speculatable:
719     return bitc::ATTR_KIND_SPECULATABLE;
720   case Attribute::StackAlignment:
721     return bitc::ATTR_KIND_STACK_ALIGNMENT;
722   case Attribute::StackProtect:
723     return bitc::ATTR_KIND_STACK_PROTECT;
724   case Attribute::StackProtectReq:
725     return bitc::ATTR_KIND_STACK_PROTECT_REQ;
726   case Attribute::StackProtectStrong:
727     return bitc::ATTR_KIND_STACK_PROTECT_STRONG;
728   case Attribute::SafeStack:
729     return bitc::ATTR_KIND_SAFESTACK;
730   case Attribute::ShadowCallStack:
731     return bitc::ATTR_KIND_SHADOWCALLSTACK;
732   case Attribute::StrictFP:
733     return bitc::ATTR_KIND_STRICT_FP;
734   case Attribute::StructRet:
735     return bitc::ATTR_KIND_STRUCT_RET;
736   case Attribute::SanitizeAddress:
737     return bitc::ATTR_KIND_SANITIZE_ADDRESS;
738   case Attribute::SanitizeHWAddress:
739     return bitc::ATTR_KIND_SANITIZE_HWADDRESS;
740   case Attribute::SanitizeThread:
741     return bitc::ATTR_KIND_SANITIZE_THREAD;
742   case Attribute::SanitizeMemory:
743     return bitc::ATTR_KIND_SANITIZE_MEMORY;
744   case Attribute::SpeculativeLoadHardening:
745     return bitc::ATTR_KIND_SPECULATIVE_LOAD_HARDENING;
746   case Attribute::SwiftError:
747     return bitc::ATTR_KIND_SWIFT_ERROR;
748   case Attribute::SwiftSelf:
749     return bitc::ATTR_KIND_SWIFT_SELF;
750   case Attribute::SwiftAsync:
751     return bitc::ATTR_KIND_SWIFT_ASYNC;
752   case Attribute::UWTable:
753     return bitc::ATTR_KIND_UW_TABLE;
754   case Attribute::VScaleRange:
755     return bitc::ATTR_KIND_VSCALE_RANGE;
756   case Attribute::WillReturn:
757     return bitc::ATTR_KIND_WILLRETURN;
758   case Attribute::WriteOnly:
759     return bitc::ATTR_KIND_WRITEONLY;
760   case Attribute::ZExt:
761     return bitc::ATTR_KIND_Z_EXT;
762   case Attribute::ImmArg:
763     return bitc::ATTR_KIND_IMMARG;
764   case Attribute::SanitizeMemTag:
765     return bitc::ATTR_KIND_SANITIZE_MEMTAG;
766   case Attribute::Preallocated:
767     return bitc::ATTR_KIND_PREALLOCATED;
768   case Attribute::NoUndef:
769     return bitc::ATTR_KIND_NOUNDEF;
770   case Attribute::ByRef:
771     return bitc::ATTR_KIND_BYREF;
772   case Attribute::MustProgress:
773     return bitc::ATTR_KIND_MUSTPROGRESS;
774   case Attribute::EndAttrKinds:
775     llvm_unreachable("Can not encode end-attribute kinds marker.");
776   case Attribute::None:
777     llvm_unreachable("Can not encode none-attribute.");
778   case Attribute::EmptyKey:
779   case Attribute::TombstoneKey:
780     llvm_unreachable("Trying to encode EmptyKey/TombstoneKey");
781   }
782 
783   llvm_unreachable("Trying to encode unknown attribute");
784 }
785 
786 void ModuleBitcodeWriter::writeAttributeGroupTable() {
787   const std::vector<ValueEnumerator::IndexAndAttrSet> &AttrGrps =
788       VE.getAttributeGroups();
789   if (AttrGrps.empty()) return;
790 
791   Stream.EnterSubblock(bitc::PARAMATTR_GROUP_BLOCK_ID, 3);
792 
793   SmallVector<uint64_t, 64> Record;
794   for (ValueEnumerator::IndexAndAttrSet Pair : AttrGrps) {
795     unsigned AttrListIndex = Pair.first;
796     AttributeSet AS = Pair.second;
797     Record.push_back(VE.getAttributeGroupID(Pair));
798     Record.push_back(AttrListIndex);
799 
800     for (Attribute Attr : AS) {
801       if (Attr.isEnumAttribute()) {
802         Record.push_back(0);
803         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
804       } else if (Attr.isIntAttribute()) {
805         Record.push_back(1);
806         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
807         Record.push_back(Attr.getValueAsInt());
808       } else if (Attr.isStringAttribute()) {
809         StringRef Kind = Attr.getKindAsString();
810         StringRef Val = Attr.getValueAsString();
811 
812         Record.push_back(Val.empty() ? 3 : 4);
813         Record.append(Kind.begin(), Kind.end());
814         Record.push_back(0);
815         if (!Val.empty()) {
816           Record.append(Val.begin(), Val.end());
817           Record.push_back(0);
818         }
819       } else {
820         assert(Attr.isTypeAttribute());
821         Type *Ty = Attr.getValueAsType();
822         Record.push_back(Ty ? 6 : 5);
823         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
824         if (Ty)
825           Record.push_back(VE.getTypeID(Attr.getValueAsType()));
826       }
827     }
828 
829     Stream.EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
830     Record.clear();
831   }
832 
833   Stream.ExitBlock();
834 }
835 
836 void ModuleBitcodeWriter::writeAttributeTable() {
837   const std::vector<AttributeList> &Attrs = VE.getAttributeLists();
838   if (Attrs.empty()) return;
839 
840   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
841 
842   SmallVector<uint64_t, 64> Record;
843   for (const AttributeList &AL : Attrs) {
844     for (unsigned i : AL.indexes()) {
845       AttributeSet AS = AL.getAttributes(i);
846       if (AS.hasAttributes())
847         Record.push_back(VE.getAttributeGroupID({i, AS}));
848     }
849 
850     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
851     Record.clear();
852   }
853 
854   Stream.ExitBlock();
855 }
856 
857 /// WriteTypeTable - Write out the type table for a module.
858 void ModuleBitcodeWriter::writeTypeTable() {
859   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
860 
861   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
862   SmallVector<uint64_t, 64> TypeVals;
863 
864   uint64_t NumBits = VE.computeBitsRequiredForTypeIndicies();
865 
866   // Abbrev for TYPE_CODE_POINTER.
867   auto Abbv = std::make_shared<BitCodeAbbrev>();
868   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
869   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
870   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
871   unsigned PtrAbbrev = Stream.EmitAbbrev(std::move(Abbv));
872 
873   // Abbrev for TYPE_CODE_OPAQUE_POINTER.
874   Abbv = std::make_shared<BitCodeAbbrev>();
875   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_OPAQUE_POINTER));
876   Abbv->Add(BitCodeAbbrevOp(0)); // Addrspace = 0
877   unsigned OpaquePtrAbbrev = Stream.EmitAbbrev(std::move(Abbv));
878 
879   // Abbrev for TYPE_CODE_FUNCTION.
880   Abbv = std::make_shared<BitCodeAbbrev>();
881   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
882   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
883   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
884   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
885   unsigned FunctionAbbrev = Stream.EmitAbbrev(std::move(Abbv));
886 
887   // Abbrev for TYPE_CODE_STRUCT_ANON.
888   Abbv = std::make_shared<BitCodeAbbrev>();
889   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
890   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
891   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
892   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
893   unsigned StructAnonAbbrev = Stream.EmitAbbrev(std::move(Abbv));
894 
895   // Abbrev for TYPE_CODE_STRUCT_NAME.
896   Abbv = std::make_shared<BitCodeAbbrev>();
897   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
898   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
899   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
900   unsigned StructNameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
901 
902   // Abbrev for TYPE_CODE_STRUCT_NAMED.
903   Abbv = std::make_shared<BitCodeAbbrev>();
904   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
905   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
906   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
907   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
908   unsigned StructNamedAbbrev = Stream.EmitAbbrev(std::move(Abbv));
909 
910   // Abbrev for TYPE_CODE_ARRAY.
911   Abbv = std::make_shared<BitCodeAbbrev>();
912   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
913   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
914   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
915   unsigned ArrayAbbrev = Stream.EmitAbbrev(std::move(Abbv));
916 
917   // Emit an entry count so the reader can reserve space.
918   TypeVals.push_back(TypeList.size());
919   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
920   TypeVals.clear();
921 
922   // Loop over all of the types, emitting each in turn.
923   for (Type *T : TypeList) {
924     int AbbrevToUse = 0;
925     unsigned Code = 0;
926 
927     switch (T->getTypeID()) {
928     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;      break;
929     case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;      break;
930     case Type::BFloatTyID:    Code = bitc::TYPE_CODE_BFLOAT;    break;
931     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;     break;
932     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE;    break;
933     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80;  break;
934     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128;     break;
935     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
936     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;     break;
937     case Type::MetadataTyID:  Code = bitc::TYPE_CODE_METADATA;  break;
938     case Type::X86_MMXTyID:   Code = bitc::TYPE_CODE_X86_MMX;   break;
939     case Type::X86_AMXTyID:   Code = bitc::TYPE_CODE_X86_AMX;   break;
940     case Type::TokenTyID:     Code = bitc::TYPE_CODE_TOKEN;     break;
941     case Type::IntegerTyID:
942       // INTEGER: [width]
943       Code = bitc::TYPE_CODE_INTEGER;
944       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
945       break;
946     case Type::PointerTyID: {
947       PointerType *PTy = cast<PointerType>(T);
948       unsigned AddressSpace = PTy->getAddressSpace();
949       if (PTy->isOpaque()) {
950         // OPAQUE_POINTER: [address space]
951         Code = bitc::TYPE_CODE_OPAQUE_POINTER;
952         TypeVals.push_back(AddressSpace);
953         if (AddressSpace == 0)
954           AbbrevToUse = OpaquePtrAbbrev;
955       } else {
956         // POINTER: [pointee type, address space]
957         Code = bitc::TYPE_CODE_POINTER;
958         TypeVals.push_back(VE.getTypeID(PTy->getNonOpaquePointerElementType()));
959         TypeVals.push_back(AddressSpace);
960         if (AddressSpace == 0)
961           AbbrevToUse = PtrAbbrev;
962       }
963       break;
964     }
965     case Type::FunctionTyID: {
966       FunctionType *FT = cast<FunctionType>(T);
967       // FUNCTION: [isvararg, retty, paramty x N]
968       Code = bitc::TYPE_CODE_FUNCTION;
969       TypeVals.push_back(FT->isVarArg());
970       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
971       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
972         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
973       AbbrevToUse = FunctionAbbrev;
974       break;
975     }
976     case Type::StructTyID: {
977       StructType *ST = cast<StructType>(T);
978       // STRUCT: [ispacked, eltty x N]
979       TypeVals.push_back(ST->isPacked());
980       // Output all of the element types.
981       for (Type *ET : ST->elements())
982         TypeVals.push_back(VE.getTypeID(ET));
983 
984       if (ST->isLiteral()) {
985         Code = bitc::TYPE_CODE_STRUCT_ANON;
986         AbbrevToUse = StructAnonAbbrev;
987       } else {
988         if (ST->isOpaque()) {
989           Code = bitc::TYPE_CODE_OPAQUE;
990         } else {
991           Code = bitc::TYPE_CODE_STRUCT_NAMED;
992           AbbrevToUse = StructNamedAbbrev;
993         }
994 
995         // Emit the name if it is present.
996         if (!ST->getName().empty())
997           writeStringRecord(Stream, bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
998                             StructNameAbbrev);
999       }
1000       break;
1001     }
1002     case Type::ArrayTyID: {
1003       ArrayType *AT = cast<ArrayType>(T);
1004       // ARRAY: [numelts, eltty]
1005       Code = bitc::TYPE_CODE_ARRAY;
1006       TypeVals.push_back(AT->getNumElements());
1007       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
1008       AbbrevToUse = ArrayAbbrev;
1009       break;
1010     }
1011     case Type::FixedVectorTyID:
1012     case Type::ScalableVectorTyID: {
1013       VectorType *VT = cast<VectorType>(T);
1014       // VECTOR [numelts, eltty] or
1015       //        [numelts, eltty, scalable]
1016       Code = bitc::TYPE_CODE_VECTOR;
1017       TypeVals.push_back(VT->getElementCount().getKnownMinValue());
1018       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
1019       if (isa<ScalableVectorType>(VT))
1020         TypeVals.push_back(true);
1021       break;
1022     }
1023     case Type::DXILPointerTyID:
1024       llvm_unreachable("DXIL pointers cannot be added to IR modules");
1025     }
1026 
1027     // Emit the finished record.
1028     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
1029     TypeVals.clear();
1030   }
1031 
1032   Stream.ExitBlock();
1033 }
1034 
1035 static unsigned getEncodedLinkage(const GlobalValue::LinkageTypes Linkage) {
1036   switch (Linkage) {
1037   case GlobalValue::ExternalLinkage:
1038     return 0;
1039   case GlobalValue::WeakAnyLinkage:
1040     return 16;
1041   case GlobalValue::AppendingLinkage:
1042     return 2;
1043   case GlobalValue::InternalLinkage:
1044     return 3;
1045   case GlobalValue::LinkOnceAnyLinkage:
1046     return 18;
1047   case GlobalValue::ExternalWeakLinkage:
1048     return 7;
1049   case GlobalValue::CommonLinkage:
1050     return 8;
1051   case GlobalValue::PrivateLinkage:
1052     return 9;
1053   case GlobalValue::WeakODRLinkage:
1054     return 17;
1055   case GlobalValue::LinkOnceODRLinkage:
1056     return 19;
1057   case GlobalValue::AvailableExternallyLinkage:
1058     return 12;
1059   }
1060   llvm_unreachable("Invalid linkage");
1061 }
1062 
1063 static unsigned getEncodedLinkage(const GlobalValue &GV) {
1064   return getEncodedLinkage(GV.getLinkage());
1065 }
1066 
1067 static uint64_t getEncodedFFlags(FunctionSummary::FFlags Flags) {
1068   uint64_t RawFlags = 0;
1069   RawFlags |= Flags.ReadNone;
1070   RawFlags |= (Flags.ReadOnly << 1);
1071   RawFlags |= (Flags.NoRecurse << 2);
1072   RawFlags |= (Flags.ReturnDoesNotAlias << 3);
1073   RawFlags |= (Flags.NoInline << 4);
1074   RawFlags |= (Flags.AlwaysInline << 5);
1075   RawFlags |= (Flags.NoUnwind << 6);
1076   RawFlags |= (Flags.MayThrow << 7);
1077   RawFlags |= (Flags.HasUnknownCall << 8);
1078   RawFlags |= (Flags.MustBeUnreachable << 9);
1079   return RawFlags;
1080 }
1081 
1082 // Decode the flags for GlobalValue in the summary. See getDecodedGVSummaryFlags
1083 // in BitcodeReader.cpp.
1084 static uint64_t getEncodedGVSummaryFlags(GlobalValueSummary::GVFlags Flags) {
1085   uint64_t RawFlags = 0;
1086 
1087   RawFlags |= Flags.NotEligibleToImport; // bool
1088   RawFlags |= (Flags.Live << 1);
1089   RawFlags |= (Flags.DSOLocal << 2);
1090   RawFlags |= (Flags.CanAutoHide << 3);
1091 
1092   // Linkage don't need to be remapped at that time for the summary. Any future
1093   // change to the getEncodedLinkage() function will need to be taken into
1094   // account here as well.
1095   RawFlags = (RawFlags << 4) | Flags.Linkage; // 4 bits
1096 
1097   RawFlags |= (Flags.Visibility << 8); // 2 bits
1098 
1099   return RawFlags;
1100 }
1101 
1102 static uint64_t getEncodedGVarFlags(GlobalVarSummary::GVarFlags Flags) {
1103   uint64_t RawFlags = Flags.MaybeReadOnly | (Flags.MaybeWriteOnly << 1) |
1104                       (Flags.Constant << 2) | Flags.VCallVisibility << 3;
1105   return RawFlags;
1106 }
1107 
1108 static unsigned getEncodedVisibility(const GlobalValue &GV) {
1109   switch (GV.getVisibility()) {
1110   case GlobalValue::DefaultVisibility:   return 0;
1111   case GlobalValue::HiddenVisibility:    return 1;
1112   case GlobalValue::ProtectedVisibility: return 2;
1113   }
1114   llvm_unreachable("Invalid visibility");
1115 }
1116 
1117 static unsigned getEncodedDLLStorageClass(const GlobalValue &GV) {
1118   switch (GV.getDLLStorageClass()) {
1119   case GlobalValue::DefaultStorageClass:   return 0;
1120   case GlobalValue::DLLImportStorageClass: return 1;
1121   case GlobalValue::DLLExportStorageClass: return 2;
1122   }
1123   llvm_unreachable("Invalid DLL storage class");
1124 }
1125 
1126 static unsigned getEncodedThreadLocalMode(const GlobalValue &GV) {
1127   switch (GV.getThreadLocalMode()) {
1128     case GlobalVariable::NotThreadLocal:         return 0;
1129     case GlobalVariable::GeneralDynamicTLSModel: return 1;
1130     case GlobalVariable::LocalDynamicTLSModel:   return 2;
1131     case GlobalVariable::InitialExecTLSModel:    return 3;
1132     case GlobalVariable::LocalExecTLSModel:      return 4;
1133   }
1134   llvm_unreachable("Invalid TLS model");
1135 }
1136 
1137 static unsigned getEncodedComdatSelectionKind(const Comdat &C) {
1138   switch (C.getSelectionKind()) {
1139   case Comdat::Any:
1140     return bitc::COMDAT_SELECTION_KIND_ANY;
1141   case Comdat::ExactMatch:
1142     return bitc::COMDAT_SELECTION_KIND_EXACT_MATCH;
1143   case Comdat::Largest:
1144     return bitc::COMDAT_SELECTION_KIND_LARGEST;
1145   case Comdat::NoDeduplicate:
1146     return bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES;
1147   case Comdat::SameSize:
1148     return bitc::COMDAT_SELECTION_KIND_SAME_SIZE;
1149   }
1150   llvm_unreachable("Invalid selection kind");
1151 }
1152 
1153 static unsigned getEncodedUnnamedAddr(const GlobalValue &GV) {
1154   switch (GV.getUnnamedAddr()) {
1155   case GlobalValue::UnnamedAddr::None:   return 0;
1156   case GlobalValue::UnnamedAddr::Local:  return 2;
1157   case GlobalValue::UnnamedAddr::Global: return 1;
1158   }
1159   llvm_unreachable("Invalid unnamed_addr");
1160 }
1161 
1162 size_t ModuleBitcodeWriter::addToStrtab(StringRef Str) {
1163   if (GenerateHash)
1164     Hasher.update(Str);
1165   return StrtabBuilder.add(Str);
1166 }
1167 
1168 void ModuleBitcodeWriter::writeComdats() {
1169   SmallVector<unsigned, 64> Vals;
1170   for (const Comdat *C : VE.getComdats()) {
1171     // COMDAT: [strtab offset, strtab size, selection_kind]
1172     Vals.push_back(addToStrtab(C->getName()));
1173     Vals.push_back(C->getName().size());
1174     Vals.push_back(getEncodedComdatSelectionKind(*C));
1175     Stream.EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
1176     Vals.clear();
1177   }
1178 }
1179 
1180 /// Write a record that will eventually hold the word offset of the
1181 /// module-level VST. For now the offset is 0, which will be backpatched
1182 /// after the real VST is written. Saves the bit offset to backpatch.
1183 void ModuleBitcodeWriter::writeValueSymbolTableForwardDecl() {
1184   // Write a placeholder value in for the offset of the real VST,
1185   // which is written after the function blocks so that it can include
1186   // the offset of each function. The placeholder offset will be
1187   // updated when the real VST is written.
1188   auto Abbv = std::make_shared<BitCodeAbbrev>();
1189   Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_VSTOFFSET));
1190   // Blocks are 32-bit aligned, so we can use a 32-bit word offset to
1191   // hold the real VST offset. Must use fixed instead of VBR as we don't
1192   // know how many VBR chunks to reserve ahead of time.
1193   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
1194   unsigned VSTOffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1195 
1196   // Emit the placeholder
1197   uint64_t Vals[] = {bitc::MODULE_CODE_VSTOFFSET, 0};
1198   Stream.EmitRecordWithAbbrev(VSTOffsetAbbrev, Vals);
1199 
1200   // Compute and save the bit offset to the placeholder, which will be
1201   // patched when the real VST is written. We can simply subtract the 32-bit
1202   // fixed size from the current bit number to get the location to backpatch.
1203   VSTOffsetPlaceholder = Stream.GetCurrentBitNo() - 32;
1204 }
1205 
1206 enum StringEncoding { SE_Char6, SE_Fixed7, SE_Fixed8 };
1207 
1208 /// Determine the encoding to use for the given string name and length.
1209 static StringEncoding getStringEncoding(StringRef Str) {
1210   bool isChar6 = true;
1211   for (char C : Str) {
1212     if (isChar6)
1213       isChar6 = BitCodeAbbrevOp::isChar6(C);
1214     if ((unsigned char)C & 128)
1215       // don't bother scanning the rest.
1216       return SE_Fixed8;
1217   }
1218   if (isChar6)
1219     return SE_Char6;
1220   return SE_Fixed7;
1221 }
1222 
1223 /// Emit top-level description of module, including target triple, inline asm,
1224 /// descriptors for global variables, and function prototype info.
1225 /// Returns the bit offset to backpatch with the location of the real VST.
1226 void ModuleBitcodeWriter::writeModuleInfo() {
1227   // Emit various pieces of data attached to a module.
1228   if (!M.getTargetTriple().empty())
1229     writeStringRecord(Stream, bitc::MODULE_CODE_TRIPLE, M.getTargetTriple(),
1230                       0 /*TODO*/);
1231   const std::string &DL = M.getDataLayoutStr();
1232   if (!DL.empty())
1233     writeStringRecord(Stream, bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/);
1234   if (!M.getModuleInlineAsm().empty())
1235     writeStringRecord(Stream, bitc::MODULE_CODE_ASM, M.getModuleInlineAsm(),
1236                       0 /*TODO*/);
1237 
1238   // Emit information about sections and GC, computing how many there are. Also
1239   // compute the maximum alignment value.
1240   std::map<std::string, unsigned> SectionMap;
1241   std::map<std::string, unsigned> GCMap;
1242   MaybeAlign MaxAlignment;
1243   unsigned MaxGlobalType = 0;
1244   const auto UpdateMaxAlignment = [&MaxAlignment](const MaybeAlign A) {
1245     if (A)
1246       MaxAlignment = !MaxAlignment ? *A : std::max(*MaxAlignment, *A);
1247   };
1248   for (const GlobalVariable &GV : M.globals()) {
1249     UpdateMaxAlignment(GV.getAlign());
1250     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getValueType()));
1251     if (GV.hasSection()) {
1252       // Give section names unique ID's.
1253       unsigned &Entry = SectionMap[std::string(GV.getSection())];
1254       if (!Entry) {
1255         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
1256                           0 /*TODO*/);
1257         Entry = SectionMap.size();
1258       }
1259     }
1260   }
1261   for (const Function &F : M) {
1262     UpdateMaxAlignment(F.getAlign());
1263     if (F.hasSection()) {
1264       // Give section names unique ID's.
1265       unsigned &Entry = SectionMap[std::string(F.getSection())];
1266       if (!Entry) {
1267         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
1268                           0 /*TODO*/);
1269         Entry = SectionMap.size();
1270       }
1271     }
1272     if (F.hasGC()) {
1273       // Same for GC names.
1274       unsigned &Entry = GCMap[F.getGC()];
1275       if (!Entry) {
1276         writeStringRecord(Stream, bitc::MODULE_CODE_GCNAME, F.getGC(),
1277                           0 /*TODO*/);
1278         Entry = GCMap.size();
1279       }
1280     }
1281   }
1282 
1283   // Emit abbrev for globals, now that we know # sections and max alignment.
1284   unsigned SimpleGVarAbbrev = 0;
1285   if (!M.global_empty()) {
1286     // Add an abbrev for common globals with no visibility or thread localness.
1287     auto Abbv = std::make_shared<BitCodeAbbrev>();
1288     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
1289     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1290     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1291     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1292                               Log2_32_Ceil(MaxGlobalType+1)));
1293     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddrSpace << 2
1294                                                            //| explicitType << 1
1295                                                            //| constant
1296     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Initializer.
1297     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // Linkage.
1298     if (!MaxAlignment)                                     // Alignment.
1299       Abbv->Add(BitCodeAbbrevOp(0));
1300     else {
1301       unsigned MaxEncAlignment = getEncodedAlign(MaxAlignment);
1302       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1303                                Log2_32_Ceil(MaxEncAlignment+1)));
1304     }
1305     if (SectionMap.empty())                                    // Section.
1306       Abbv->Add(BitCodeAbbrevOp(0));
1307     else
1308       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1309                                Log2_32_Ceil(SectionMap.size()+1)));
1310     // Don't bother emitting vis + thread local.
1311     SimpleGVarAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1312   }
1313 
1314   SmallVector<unsigned, 64> Vals;
1315   // Emit the module's source file name.
1316   {
1317     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
1318     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
1319     if (Bits == SE_Char6)
1320       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
1321     else if (Bits == SE_Fixed7)
1322       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
1323 
1324     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
1325     auto Abbv = std::make_shared<BitCodeAbbrev>();
1326     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
1327     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1328     Abbv->Add(AbbrevOpToUse);
1329     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1330 
1331     for (const auto P : M.getSourceFileName())
1332       Vals.push_back((unsigned char)P);
1333 
1334     // Emit the finished record.
1335     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
1336     Vals.clear();
1337   }
1338 
1339   // Emit the global variable information.
1340   for (const GlobalVariable &GV : M.globals()) {
1341     unsigned AbbrevToUse = 0;
1342 
1343     // GLOBALVAR: [strtab offset, strtab size, type, isconst, initid,
1344     //             linkage, alignment, section, visibility, threadlocal,
1345     //             unnamed_addr, externally_initialized, dllstorageclass,
1346     //             comdat, attributes, DSO_Local]
1347     Vals.push_back(addToStrtab(GV.getName()));
1348     Vals.push_back(GV.getName().size());
1349     Vals.push_back(VE.getTypeID(GV.getValueType()));
1350     Vals.push_back(GV.getType()->getAddressSpace() << 2 | 2 | GV.isConstant());
1351     Vals.push_back(GV.isDeclaration() ? 0 :
1352                    (VE.getValueID(GV.getInitializer()) + 1));
1353     Vals.push_back(getEncodedLinkage(GV));
1354     Vals.push_back(getEncodedAlign(GV.getAlign()));
1355     Vals.push_back(GV.hasSection() ? SectionMap[std::string(GV.getSection())]
1356                                    : 0);
1357     if (GV.isThreadLocal() ||
1358         GV.getVisibility() != GlobalValue::DefaultVisibility ||
1359         GV.getUnnamedAddr() != GlobalValue::UnnamedAddr::None ||
1360         GV.isExternallyInitialized() ||
1361         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
1362         GV.hasComdat() ||
1363         GV.hasAttributes() ||
1364         GV.isDSOLocal() ||
1365         GV.hasPartition()) {
1366       Vals.push_back(getEncodedVisibility(GV));
1367       Vals.push_back(getEncodedThreadLocalMode(GV));
1368       Vals.push_back(getEncodedUnnamedAddr(GV));
1369       Vals.push_back(GV.isExternallyInitialized());
1370       Vals.push_back(getEncodedDLLStorageClass(GV));
1371       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
1372 
1373       auto AL = GV.getAttributesAsList(AttributeList::FunctionIndex);
1374       Vals.push_back(VE.getAttributeListID(AL));
1375 
1376       Vals.push_back(GV.isDSOLocal());
1377       Vals.push_back(addToStrtab(GV.getPartition()));
1378       Vals.push_back(GV.getPartition().size());
1379     } else {
1380       AbbrevToUse = SimpleGVarAbbrev;
1381     }
1382 
1383     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
1384     Vals.clear();
1385   }
1386 
1387   // Emit the function proto information.
1388   for (const Function &F : M) {
1389     // FUNCTION:  [strtab offset, strtab size, type, callingconv, isproto,
1390     //             linkage, paramattrs, alignment, section, visibility, gc,
1391     //             unnamed_addr, prologuedata, dllstorageclass, comdat,
1392     //             prefixdata, personalityfn, DSO_Local, addrspace]
1393     Vals.push_back(addToStrtab(F.getName()));
1394     Vals.push_back(F.getName().size());
1395     Vals.push_back(VE.getTypeID(F.getFunctionType()));
1396     Vals.push_back(F.getCallingConv());
1397     Vals.push_back(F.isDeclaration());
1398     Vals.push_back(getEncodedLinkage(F));
1399     Vals.push_back(VE.getAttributeListID(F.getAttributes()));
1400     Vals.push_back(getEncodedAlign(F.getAlign()));
1401     Vals.push_back(F.hasSection() ? SectionMap[std::string(F.getSection())]
1402                                   : 0);
1403     Vals.push_back(getEncodedVisibility(F));
1404     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
1405     Vals.push_back(getEncodedUnnamedAddr(F));
1406     Vals.push_back(F.hasPrologueData() ? (VE.getValueID(F.getPrologueData()) + 1)
1407                                        : 0);
1408     Vals.push_back(getEncodedDLLStorageClass(F));
1409     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
1410     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
1411                                      : 0);
1412     Vals.push_back(
1413         F.hasPersonalityFn() ? (VE.getValueID(F.getPersonalityFn()) + 1) : 0);
1414 
1415     Vals.push_back(F.isDSOLocal());
1416     Vals.push_back(F.getAddressSpace());
1417     Vals.push_back(addToStrtab(F.getPartition()));
1418     Vals.push_back(F.getPartition().size());
1419 
1420     unsigned AbbrevToUse = 0;
1421     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
1422     Vals.clear();
1423   }
1424 
1425   // Emit the alias information.
1426   for (const GlobalAlias &A : M.aliases()) {
1427     // ALIAS: [strtab offset, strtab size, alias type, aliasee val#, linkage,
1428     //         visibility, dllstorageclass, threadlocal, unnamed_addr,
1429     //         DSO_Local]
1430     Vals.push_back(addToStrtab(A.getName()));
1431     Vals.push_back(A.getName().size());
1432     Vals.push_back(VE.getTypeID(A.getValueType()));
1433     Vals.push_back(A.getType()->getAddressSpace());
1434     Vals.push_back(VE.getValueID(A.getAliasee()));
1435     Vals.push_back(getEncodedLinkage(A));
1436     Vals.push_back(getEncodedVisibility(A));
1437     Vals.push_back(getEncodedDLLStorageClass(A));
1438     Vals.push_back(getEncodedThreadLocalMode(A));
1439     Vals.push_back(getEncodedUnnamedAddr(A));
1440     Vals.push_back(A.isDSOLocal());
1441     Vals.push_back(addToStrtab(A.getPartition()));
1442     Vals.push_back(A.getPartition().size());
1443 
1444     unsigned AbbrevToUse = 0;
1445     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
1446     Vals.clear();
1447   }
1448 
1449   // Emit the ifunc information.
1450   for (const GlobalIFunc &I : M.ifuncs()) {
1451     // IFUNC: [strtab offset, strtab size, ifunc type, address space, resolver
1452     //         val#, linkage, visibility, DSO_Local]
1453     Vals.push_back(addToStrtab(I.getName()));
1454     Vals.push_back(I.getName().size());
1455     Vals.push_back(VE.getTypeID(I.getValueType()));
1456     Vals.push_back(I.getType()->getAddressSpace());
1457     Vals.push_back(VE.getValueID(I.getResolver()));
1458     Vals.push_back(getEncodedLinkage(I));
1459     Vals.push_back(getEncodedVisibility(I));
1460     Vals.push_back(I.isDSOLocal());
1461     Vals.push_back(addToStrtab(I.getPartition()));
1462     Vals.push_back(I.getPartition().size());
1463     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
1464     Vals.clear();
1465   }
1466 
1467   writeValueSymbolTableForwardDecl();
1468 }
1469 
1470 static uint64_t getOptimizationFlags(const Value *V) {
1471   uint64_t Flags = 0;
1472 
1473   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
1474     if (OBO->hasNoSignedWrap())
1475       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
1476     if (OBO->hasNoUnsignedWrap())
1477       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
1478   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
1479     if (PEO->isExact())
1480       Flags |= 1 << bitc::PEO_EXACT;
1481   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
1482     if (FPMO->hasAllowReassoc())
1483       Flags |= bitc::AllowReassoc;
1484     if (FPMO->hasNoNaNs())
1485       Flags |= bitc::NoNaNs;
1486     if (FPMO->hasNoInfs())
1487       Flags |= bitc::NoInfs;
1488     if (FPMO->hasNoSignedZeros())
1489       Flags |= bitc::NoSignedZeros;
1490     if (FPMO->hasAllowReciprocal())
1491       Flags |= bitc::AllowReciprocal;
1492     if (FPMO->hasAllowContract())
1493       Flags |= bitc::AllowContract;
1494     if (FPMO->hasApproxFunc())
1495       Flags |= bitc::ApproxFunc;
1496   }
1497 
1498   return Flags;
1499 }
1500 
1501 void ModuleBitcodeWriter::writeValueAsMetadata(
1502     const ValueAsMetadata *MD, SmallVectorImpl<uint64_t> &Record) {
1503   // Mimic an MDNode with a value as one operand.
1504   Value *V = MD->getValue();
1505   Record.push_back(VE.getTypeID(V->getType()));
1506   Record.push_back(VE.getValueID(V));
1507   Stream.EmitRecord(bitc::METADATA_VALUE, Record, 0);
1508   Record.clear();
1509 }
1510 
1511 void ModuleBitcodeWriter::writeMDTuple(const MDTuple *N,
1512                                        SmallVectorImpl<uint64_t> &Record,
1513                                        unsigned Abbrev) {
1514   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
1515     Metadata *MD = N->getOperand(i);
1516     assert(!(MD && isa<LocalAsMetadata>(MD)) &&
1517            "Unexpected function-local metadata");
1518     Record.push_back(VE.getMetadataOrNullID(MD));
1519   }
1520   Stream.EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
1521                                     : bitc::METADATA_NODE,
1522                     Record, Abbrev);
1523   Record.clear();
1524 }
1525 
1526 unsigned ModuleBitcodeWriter::createDILocationAbbrev() {
1527   // Assume the column is usually under 128, and always output the inlined-at
1528   // location (it's never more expensive than building an array size 1).
1529   auto Abbv = std::make_shared<BitCodeAbbrev>();
1530   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
1531   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1532   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1533   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1534   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1535   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1536   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1537   return Stream.EmitAbbrev(std::move(Abbv));
1538 }
1539 
1540 void ModuleBitcodeWriter::writeDILocation(const DILocation *N,
1541                                           SmallVectorImpl<uint64_t> &Record,
1542                                           unsigned &Abbrev) {
1543   if (!Abbrev)
1544     Abbrev = createDILocationAbbrev();
1545 
1546   Record.push_back(N->isDistinct());
1547   Record.push_back(N->getLine());
1548   Record.push_back(N->getColumn());
1549   Record.push_back(VE.getMetadataID(N->getScope()));
1550   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
1551   Record.push_back(N->isImplicitCode());
1552 
1553   Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
1554   Record.clear();
1555 }
1556 
1557 unsigned ModuleBitcodeWriter::createGenericDINodeAbbrev() {
1558   // Assume the column is usually under 128, and always output the inlined-at
1559   // location (it's never more expensive than building an array size 1).
1560   auto Abbv = std::make_shared<BitCodeAbbrev>();
1561   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
1562   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1563   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1564   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1565   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1566   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1567   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1568   return Stream.EmitAbbrev(std::move(Abbv));
1569 }
1570 
1571 void ModuleBitcodeWriter::writeGenericDINode(const GenericDINode *N,
1572                                              SmallVectorImpl<uint64_t> &Record,
1573                                              unsigned &Abbrev) {
1574   if (!Abbrev)
1575     Abbrev = createGenericDINodeAbbrev();
1576 
1577   Record.push_back(N->isDistinct());
1578   Record.push_back(N->getTag());
1579   Record.push_back(0); // Per-tag version field; unused for now.
1580 
1581   for (auto &I : N->operands())
1582     Record.push_back(VE.getMetadataOrNullID(I));
1583 
1584   Stream.EmitRecord(bitc::METADATA_GENERIC_DEBUG, Record, Abbrev);
1585   Record.clear();
1586 }
1587 
1588 void ModuleBitcodeWriter::writeDISubrange(const DISubrange *N,
1589                                           SmallVectorImpl<uint64_t> &Record,
1590                                           unsigned Abbrev) {
1591   const uint64_t Version = 2 << 1;
1592   Record.push_back((uint64_t)N->isDistinct() | Version);
1593   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1594   Record.push_back(VE.getMetadataOrNullID(N->getRawLowerBound()));
1595   Record.push_back(VE.getMetadataOrNullID(N->getRawUpperBound()));
1596   Record.push_back(VE.getMetadataOrNullID(N->getRawStride()));
1597 
1598   Stream.EmitRecord(bitc::METADATA_SUBRANGE, Record, Abbrev);
1599   Record.clear();
1600 }
1601 
1602 void ModuleBitcodeWriter::writeDIGenericSubrange(
1603     const DIGenericSubrange *N, SmallVectorImpl<uint64_t> &Record,
1604     unsigned Abbrev) {
1605   Record.push_back((uint64_t)N->isDistinct());
1606   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1607   Record.push_back(VE.getMetadataOrNullID(N->getRawLowerBound()));
1608   Record.push_back(VE.getMetadataOrNullID(N->getRawUpperBound()));
1609   Record.push_back(VE.getMetadataOrNullID(N->getRawStride()));
1610 
1611   Stream.EmitRecord(bitc::METADATA_GENERIC_SUBRANGE, Record, Abbrev);
1612   Record.clear();
1613 }
1614 
1615 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
1616   if ((int64_t)V >= 0)
1617     Vals.push_back(V << 1);
1618   else
1619     Vals.push_back((-V << 1) | 1);
1620 }
1621 
1622 static void emitWideAPInt(SmallVectorImpl<uint64_t> &Vals, const APInt &A) {
1623   // We have an arbitrary precision integer value to write whose
1624   // bit width is > 64. However, in canonical unsigned integer
1625   // format it is likely that the high bits are going to be zero.
1626   // So, we only write the number of active words.
1627   unsigned NumWords = A.getActiveWords();
1628   const uint64_t *RawData = A.getRawData();
1629   for (unsigned i = 0; i < NumWords; i++)
1630     emitSignedInt64(Vals, RawData[i]);
1631 }
1632 
1633 void ModuleBitcodeWriter::writeDIEnumerator(const DIEnumerator *N,
1634                                             SmallVectorImpl<uint64_t> &Record,
1635                                             unsigned Abbrev) {
1636   const uint64_t IsBigInt = 1 << 2;
1637   Record.push_back(IsBigInt | (N->isUnsigned() << 1) | N->isDistinct());
1638   Record.push_back(N->getValue().getBitWidth());
1639   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1640   emitWideAPInt(Record, N->getValue());
1641 
1642   Stream.EmitRecord(bitc::METADATA_ENUMERATOR, Record, Abbrev);
1643   Record.clear();
1644 }
1645 
1646 void ModuleBitcodeWriter::writeDIBasicType(const DIBasicType *N,
1647                                            SmallVectorImpl<uint64_t> &Record,
1648                                            unsigned Abbrev) {
1649   Record.push_back(N->isDistinct());
1650   Record.push_back(N->getTag());
1651   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1652   Record.push_back(N->getSizeInBits());
1653   Record.push_back(N->getAlignInBits());
1654   Record.push_back(N->getEncoding());
1655   Record.push_back(N->getFlags());
1656 
1657   Stream.EmitRecord(bitc::METADATA_BASIC_TYPE, Record, Abbrev);
1658   Record.clear();
1659 }
1660 
1661 void ModuleBitcodeWriter::writeDIStringType(const DIStringType *N,
1662                                             SmallVectorImpl<uint64_t> &Record,
1663                                             unsigned Abbrev) {
1664   Record.push_back(N->isDistinct());
1665   Record.push_back(N->getTag());
1666   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1667   Record.push_back(VE.getMetadataOrNullID(N->getStringLength()));
1668   Record.push_back(VE.getMetadataOrNullID(N->getStringLengthExp()));
1669   Record.push_back(VE.getMetadataOrNullID(N->getStringLocationExp()));
1670   Record.push_back(N->getSizeInBits());
1671   Record.push_back(N->getAlignInBits());
1672   Record.push_back(N->getEncoding());
1673 
1674   Stream.EmitRecord(bitc::METADATA_STRING_TYPE, Record, Abbrev);
1675   Record.clear();
1676 }
1677 
1678 void ModuleBitcodeWriter::writeDIDerivedType(const DIDerivedType *N,
1679                                              SmallVectorImpl<uint64_t> &Record,
1680                                              unsigned Abbrev) {
1681   Record.push_back(N->isDistinct());
1682   Record.push_back(N->getTag());
1683   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1684   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1685   Record.push_back(N->getLine());
1686   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1687   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1688   Record.push_back(N->getSizeInBits());
1689   Record.push_back(N->getAlignInBits());
1690   Record.push_back(N->getOffsetInBits());
1691   Record.push_back(N->getFlags());
1692   Record.push_back(VE.getMetadataOrNullID(N->getExtraData()));
1693 
1694   // DWARF address space is encoded as N->getDWARFAddressSpace() + 1. 0 means
1695   // that there is no DWARF address space associated with DIDerivedType.
1696   if (const auto &DWARFAddressSpace = N->getDWARFAddressSpace())
1697     Record.push_back(*DWARFAddressSpace + 1);
1698   else
1699     Record.push_back(0);
1700 
1701   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1702 
1703   Stream.EmitRecord(bitc::METADATA_DERIVED_TYPE, Record, Abbrev);
1704   Record.clear();
1705 }
1706 
1707 void ModuleBitcodeWriter::writeDICompositeType(
1708     const DICompositeType *N, SmallVectorImpl<uint64_t> &Record,
1709     unsigned Abbrev) {
1710   const unsigned IsNotUsedInOldTypeRef = 0x2;
1711   Record.push_back(IsNotUsedInOldTypeRef | (unsigned)N->isDistinct());
1712   Record.push_back(N->getTag());
1713   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1714   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1715   Record.push_back(N->getLine());
1716   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1717   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1718   Record.push_back(N->getSizeInBits());
1719   Record.push_back(N->getAlignInBits());
1720   Record.push_back(N->getOffsetInBits());
1721   Record.push_back(N->getFlags());
1722   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1723   Record.push_back(N->getRuntimeLang());
1724   Record.push_back(VE.getMetadataOrNullID(N->getVTableHolder()));
1725   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1726   Record.push_back(VE.getMetadataOrNullID(N->getRawIdentifier()));
1727   Record.push_back(VE.getMetadataOrNullID(N->getDiscriminator()));
1728   Record.push_back(VE.getMetadataOrNullID(N->getRawDataLocation()));
1729   Record.push_back(VE.getMetadataOrNullID(N->getRawAssociated()));
1730   Record.push_back(VE.getMetadataOrNullID(N->getRawAllocated()));
1731   Record.push_back(VE.getMetadataOrNullID(N->getRawRank()));
1732   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1733 
1734   Stream.EmitRecord(bitc::METADATA_COMPOSITE_TYPE, Record, Abbrev);
1735   Record.clear();
1736 }
1737 
1738 void ModuleBitcodeWriter::writeDISubroutineType(
1739     const DISubroutineType *N, SmallVectorImpl<uint64_t> &Record,
1740     unsigned Abbrev) {
1741   const unsigned HasNoOldTypeRefs = 0x2;
1742   Record.push_back(HasNoOldTypeRefs | (unsigned)N->isDistinct());
1743   Record.push_back(N->getFlags());
1744   Record.push_back(VE.getMetadataOrNullID(N->getTypeArray().get()));
1745   Record.push_back(N->getCC());
1746 
1747   Stream.EmitRecord(bitc::METADATA_SUBROUTINE_TYPE, Record, Abbrev);
1748   Record.clear();
1749 }
1750 
1751 void ModuleBitcodeWriter::writeDIFile(const DIFile *N,
1752                                       SmallVectorImpl<uint64_t> &Record,
1753                                       unsigned Abbrev) {
1754   Record.push_back(N->isDistinct());
1755   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
1756   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
1757   if (N->getRawChecksum()) {
1758     Record.push_back(N->getRawChecksum()->Kind);
1759     Record.push_back(VE.getMetadataOrNullID(N->getRawChecksum()->Value));
1760   } else {
1761     // Maintain backwards compatibility with the old internal representation of
1762     // CSK_None in ChecksumKind by writing nulls here when Checksum is None.
1763     Record.push_back(0);
1764     Record.push_back(VE.getMetadataOrNullID(nullptr));
1765   }
1766   auto Source = N->getRawSource();
1767   if (Source)
1768     Record.push_back(VE.getMetadataOrNullID(*Source));
1769 
1770   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
1771   Record.clear();
1772 }
1773 
1774 void ModuleBitcodeWriter::writeDICompileUnit(const DICompileUnit *N,
1775                                              SmallVectorImpl<uint64_t> &Record,
1776                                              unsigned Abbrev) {
1777   assert(N->isDistinct() && "Expected distinct compile units");
1778   Record.push_back(/* IsDistinct */ true);
1779   Record.push_back(N->getSourceLanguage());
1780   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1781   Record.push_back(VE.getMetadataOrNullID(N->getRawProducer()));
1782   Record.push_back(N->isOptimized());
1783   Record.push_back(VE.getMetadataOrNullID(N->getRawFlags()));
1784   Record.push_back(N->getRuntimeVersion());
1785   Record.push_back(VE.getMetadataOrNullID(N->getRawSplitDebugFilename()));
1786   Record.push_back(N->getEmissionKind());
1787   Record.push_back(VE.getMetadataOrNullID(N->getEnumTypes().get()));
1788   Record.push_back(VE.getMetadataOrNullID(N->getRetainedTypes().get()));
1789   Record.push_back(/* subprograms */ 0);
1790   Record.push_back(VE.getMetadataOrNullID(N->getGlobalVariables().get()));
1791   Record.push_back(VE.getMetadataOrNullID(N->getImportedEntities().get()));
1792   Record.push_back(N->getDWOId());
1793   Record.push_back(VE.getMetadataOrNullID(N->getMacros().get()));
1794   Record.push_back(N->getSplitDebugInlining());
1795   Record.push_back(N->getDebugInfoForProfiling());
1796   Record.push_back((unsigned)N->getNameTableKind());
1797   Record.push_back(N->getRangesBaseAddress());
1798   Record.push_back(VE.getMetadataOrNullID(N->getRawSysRoot()));
1799   Record.push_back(VE.getMetadataOrNullID(N->getRawSDK()));
1800 
1801   Stream.EmitRecord(bitc::METADATA_COMPILE_UNIT, Record, Abbrev);
1802   Record.clear();
1803 }
1804 
1805 void ModuleBitcodeWriter::writeDISubprogram(const DISubprogram *N,
1806                                             SmallVectorImpl<uint64_t> &Record,
1807                                             unsigned Abbrev) {
1808   const uint64_t HasUnitFlag = 1 << 1;
1809   const uint64_t HasSPFlagsFlag = 1 << 2;
1810   Record.push_back(uint64_t(N->isDistinct()) | HasUnitFlag | HasSPFlagsFlag);
1811   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1812   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1813   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1814   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1815   Record.push_back(N->getLine());
1816   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1817   Record.push_back(N->getScopeLine());
1818   Record.push_back(VE.getMetadataOrNullID(N->getContainingType()));
1819   Record.push_back(N->getSPFlags());
1820   Record.push_back(N->getVirtualIndex());
1821   Record.push_back(N->getFlags());
1822   Record.push_back(VE.getMetadataOrNullID(N->getRawUnit()));
1823   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1824   Record.push_back(VE.getMetadataOrNullID(N->getDeclaration()));
1825   Record.push_back(VE.getMetadataOrNullID(N->getRetainedNodes().get()));
1826   Record.push_back(N->getThisAdjustment());
1827   Record.push_back(VE.getMetadataOrNullID(N->getThrownTypes().get()));
1828   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1829   Record.push_back(VE.getMetadataOrNullID(N->getRawTargetFuncName()));
1830 
1831   Stream.EmitRecord(bitc::METADATA_SUBPROGRAM, Record, Abbrev);
1832   Record.clear();
1833 }
1834 
1835 void ModuleBitcodeWriter::writeDILexicalBlock(const DILexicalBlock *N,
1836                                               SmallVectorImpl<uint64_t> &Record,
1837                                               unsigned Abbrev) {
1838   Record.push_back(N->isDistinct());
1839   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1840   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1841   Record.push_back(N->getLine());
1842   Record.push_back(N->getColumn());
1843 
1844   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK, Record, Abbrev);
1845   Record.clear();
1846 }
1847 
1848 void ModuleBitcodeWriter::writeDILexicalBlockFile(
1849     const DILexicalBlockFile *N, SmallVectorImpl<uint64_t> &Record,
1850     unsigned Abbrev) {
1851   Record.push_back(N->isDistinct());
1852   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1853   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1854   Record.push_back(N->getDiscriminator());
1855 
1856   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK_FILE, Record, Abbrev);
1857   Record.clear();
1858 }
1859 
1860 void ModuleBitcodeWriter::writeDICommonBlock(const DICommonBlock *N,
1861                                              SmallVectorImpl<uint64_t> &Record,
1862                                              unsigned Abbrev) {
1863   Record.push_back(N->isDistinct());
1864   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1865   Record.push_back(VE.getMetadataOrNullID(N->getDecl()));
1866   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1867   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1868   Record.push_back(N->getLineNo());
1869 
1870   Stream.EmitRecord(bitc::METADATA_COMMON_BLOCK, Record, Abbrev);
1871   Record.clear();
1872 }
1873 
1874 void ModuleBitcodeWriter::writeDINamespace(const DINamespace *N,
1875                                            SmallVectorImpl<uint64_t> &Record,
1876                                            unsigned Abbrev) {
1877   Record.push_back(N->isDistinct() | N->getExportSymbols() << 1);
1878   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1879   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1880 
1881   Stream.EmitRecord(bitc::METADATA_NAMESPACE, Record, Abbrev);
1882   Record.clear();
1883 }
1884 
1885 void ModuleBitcodeWriter::writeDIMacro(const DIMacro *N,
1886                                        SmallVectorImpl<uint64_t> &Record,
1887                                        unsigned Abbrev) {
1888   Record.push_back(N->isDistinct());
1889   Record.push_back(N->getMacinfoType());
1890   Record.push_back(N->getLine());
1891   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1892   Record.push_back(VE.getMetadataOrNullID(N->getRawValue()));
1893 
1894   Stream.EmitRecord(bitc::METADATA_MACRO, Record, Abbrev);
1895   Record.clear();
1896 }
1897 
1898 void ModuleBitcodeWriter::writeDIMacroFile(const DIMacroFile *N,
1899                                            SmallVectorImpl<uint64_t> &Record,
1900                                            unsigned Abbrev) {
1901   Record.push_back(N->isDistinct());
1902   Record.push_back(N->getMacinfoType());
1903   Record.push_back(N->getLine());
1904   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1905   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1906 
1907   Stream.EmitRecord(bitc::METADATA_MACRO_FILE, Record, Abbrev);
1908   Record.clear();
1909 }
1910 
1911 void ModuleBitcodeWriter::writeDIArgList(const DIArgList *N,
1912                                          SmallVectorImpl<uint64_t> &Record,
1913                                          unsigned Abbrev) {
1914   Record.reserve(N->getArgs().size());
1915   for (ValueAsMetadata *MD : N->getArgs())
1916     Record.push_back(VE.getMetadataID(MD));
1917 
1918   Stream.EmitRecord(bitc::METADATA_ARG_LIST, Record, Abbrev);
1919   Record.clear();
1920 }
1921 
1922 void ModuleBitcodeWriter::writeDIModule(const DIModule *N,
1923                                         SmallVectorImpl<uint64_t> &Record,
1924                                         unsigned Abbrev) {
1925   Record.push_back(N->isDistinct());
1926   for (auto &I : N->operands())
1927     Record.push_back(VE.getMetadataOrNullID(I));
1928   Record.push_back(N->getLineNo());
1929   Record.push_back(N->getIsDecl());
1930 
1931   Stream.EmitRecord(bitc::METADATA_MODULE, Record, Abbrev);
1932   Record.clear();
1933 }
1934 
1935 void ModuleBitcodeWriter::writeDITemplateTypeParameter(
1936     const DITemplateTypeParameter *N, SmallVectorImpl<uint64_t> &Record,
1937     unsigned Abbrev) {
1938   Record.push_back(N->isDistinct());
1939   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1940   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1941   Record.push_back(N->isDefault());
1942 
1943   Stream.EmitRecord(bitc::METADATA_TEMPLATE_TYPE, Record, Abbrev);
1944   Record.clear();
1945 }
1946 
1947 void ModuleBitcodeWriter::writeDITemplateValueParameter(
1948     const DITemplateValueParameter *N, SmallVectorImpl<uint64_t> &Record,
1949     unsigned Abbrev) {
1950   Record.push_back(N->isDistinct());
1951   Record.push_back(N->getTag());
1952   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1953   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1954   Record.push_back(N->isDefault());
1955   Record.push_back(VE.getMetadataOrNullID(N->getValue()));
1956 
1957   Stream.EmitRecord(bitc::METADATA_TEMPLATE_VALUE, Record, Abbrev);
1958   Record.clear();
1959 }
1960 
1961 void ModuleBitcodeWriter::writeDIGlobalVariable(
1962     const DIGlobalVariable *N, SmallVectorImpl<uint64_t> &Record,
1963     unsigned Abbrev) {
1964   const uint64_t Version = 2 << 1;
1965   Record.push_back((uint64_t)N->isDistinct() | Version);
1966   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1967   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1968   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1969   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1970   Record.push_back(N->getLine());
1971   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1972   Record.push_back(N->isLocalToUnit());
1973   Record.push_back(N->isDefinition());
1974   Record.push_back(VE.getMetadataOrNullID(N->getStaticDataMemberDeclaration()));
1975   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams()));
1976   Record.push_back(N->getAlignInBits());
1977   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1978 
1979   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR, Record, Abbrev);
1980   Record.clear();
1981 }
1982 
1983 void ModuleBitcodeWriter::writeDILocalVariable(
1984     const DILocalVariable *N, SmallVectorImpl<uint64_t> &Record,
1985     unsigned Abbrev) {
1986   // In order to support all possible bitcode formats in BitcodeReader we need
1987   // to distinguish the following cases:
1988   // 1) Record has no artificial tag (Record[1]),
1989   //   has no obsolete inlinedAt field (Record[9]).
1990   //   In this case Record size will be 8, HasAlignment flag is false.
1991   // 2) Record has artificial tag (Record[1]),
1992   //   has no obsolete inlignedAt field (Record[9]).
1993   //   In this case Record size will be 9, HasAlignment flag is false.
1994   // 3) Record has both artificial tag (Record[1]) and
1995   //   obsolete inlignedAt field (Record[9]).
1996   //   In this case Record size will be 10, HasAlignment flag is false.
1997   // 4) Record has neither artificial tag, nor inlignedAt field, but
1998   //   HasAlignment flag is true and Record[8] contains alignment value.
1999   const uint64_t HasAlignmentFlag = 1 << 1;
2000   Record.push_back((uint64_t)N->isDistinct() | HasAlignmentFlag);
2001   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2002   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2003   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2004   Record.push_back(N->getLine());
2005   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2006   Record.push_back(N->getArg());
2007   Record.push_back(N->getFlags());
2008   Record.push_back(N->getAlignInBits());
2009   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
2010 
2011   Stream.EmitRecord(bitc::METADATA_LOCAL_VAR, Record, Abbrev);
2012   Record.clear();
2013 }
2014 
2015 void ModuleBitcodeWriter::writeDILabel(
2016     const DILabel *N, SmallVectorImpl<uint64_t> &Record,
2017     unsigned Abbrev) {
2018   Record.push_back((uint64_t)N->isDistinct());
2019   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2020   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2021   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2022   Record.push_back(N->getLine());
2023 
2024   Stream.EmitRecord(bitc::METADATA_LABEL, Record, Abbrev);
2025   Record.clear();
2026 }
2027 
2028 void ModuleBitcodeWriter::writeDIExpression(const DIExpression *N,
2029                                             SmallVectorImpl<uint64_t> &Record,
2030                                             unsigned Abbrev) {
2031   Record.reserve(N->getElements().size() + 1);
2032   const uint64_t Version = 3 << 1;
2033   Record.push_back((uint64_t)N->isDistinct() | Version);
2034   Record.append(N->elements_begin(), N->elements_end());
2035 
2036   Stream.EmitRecord(bitc::METADATA_EXPRESSION, Record, Abbrev);
2037   Record.clear();
2038 }
2039 
2040 void ModuleBitcodeWriter::writeDIGlobalVariableExpression(
2041     const DIGlobalVariableExpression *N, SmallVectorImpl<uint64_t> &Record,
2042     unsigned Abbrev) {
2043   Record.push_back(N->isDistinct());
2044   Record.push_back(VE.getMetadataOrNullID(N->getVariable()));
2045   Record.push_back(VE.getMetadataOrNullID(N->getExpression()));
2046 
2047   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR_EXPR, Record, Abbrev);
2048   Record.clear();
2049 }
2050 
2051 void ModuleBitcodeWriter::writeDIObjCProperty(const DIObjCProperty *N,
2052                                               SmallVectorImpl<uint64_t> &Record,
2053                                               unsigned Abbrev) {
2054   Record.push_back(N->isDistinct());
2055   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2056   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2057   Record.push_back(N->getLine());
2058   Record.push_back(VE.getMetadataOrNullID(N->getRawSetterName()));
2059   Record.push_back(VE.getMetadataOrNullID(N->getRawGetterName()));
2060   Record.push_back(N->getAttributes());
2061   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2062 
2063   Stream.EmitRecord(bitc::METADATA_OBJC_PROPERTY, Record, Abbrev);
2064   Record.clear();
2065 }
2066 
2067 void ModuleBitcodeWriter::writeDIImportedEntity(
2068     const DIImportedEntity *N, SmallVectorImpl<uint64_t> &Record,
2069     unsigned Abbrev) {
2070   Record.push_back(N->isDistinct());
2071   Record.push_back(N->getTag());
2072   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2073   Record.push_back(VE.getMetadataOrNullID(N->getEntity()));
2074   Record.push_back(N->getLine());
2075   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2076   Record.push_back(VE.getMetadataOrNullID(N->getRawFile()));
2077   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
2078 
2079   Stream.EmitRecord(bitc::METADATA_IMPORTED_ENTITY, Record, Abbrev);
2080   Record.clear();
2081 }
2082 
2083 unsigned ModuleBitcodeWriter::createNamedMetadataAbbrev() {
2084   auto Abbv = std::make_shared<BitCodeAbbrev>();
2085   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
2086   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2087   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2088   return Stream.EmitAbbrev(std::move(Abbv));
2089 }
2090 
2091 void ModuleBitcodeWriter::writeNamedMetadata(
2092     SmallVectorImpl<uint64_t> &Record) {
2093   if (M.named_metadata_empty())
2094     return;
2095 
2096   unsigned Abbrev = createNamedMetadataAbbrev();
2097   for (const NamedMDNode &NMD : M.named_metadata()) {
2098     // Write name.
2099     StringRef Str = NMD.getName();
2100     Record.append(Str.bytes_begin(), Str.bytes_end());
2101     Stream.EmitRecord(bitc::METADATA_NAME, Record, Abbrev);
2102     Record.clear();
2103 
2104     // Write named metadata operands.
2105     for (const MDNode *N : NMD.operands())
2106       Record.push_back(VE.getMetadataID(N));
2107     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
2108     Record.clear();
2109   }
2110 }
2111 
2112 unsigned ModuleBitcodeWriter::createMetadataStringsAbbrev() {
2113   auto Abbv = std::make_shared<BitCodeAbbrev>();
2114   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRINGS));
2115   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // # of strings
2116   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // offset to chars
2117   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
2118   return Stream.EmitAbbrev(std::move(Abbv));
2119 }
2120 
2121 /// Write out a record for MDString.
2122 ///
2123 /// All the metadata strings in a metadata block are emitted in a single
2124 /// record.  The sizes and strings themselves are shoved into a blob.
2125 void ModuleBitcodeWriter::writeMetadataStrings(
2126     ArrayRef<const Metadata *> Strings, SmallVectorImpl<uint64_t> &Record) {
2127   if (Strings.empty())
2128     return;
2129 
2130   // Start the record with the number of strings.
2131   Record.push_back(bitc::METADATA_STRINGS);
2132   Record.push_back(Strings.size());
2133 
2134   // Emit the sizes of the strings in the blob.
2135   SmallString<256> Blob;
2136   {
2137     BitstreamWriter W(Blob);
2138     for (const Metadata *MD : Strings)
2139       W.EmitVBR(cast<MDString>(MD)->getLength(), 6);
2140     W.FlushToWord();
2141   }
2142 
2143   // Add the offset to the strings to the record.
2144   Record.push_back(Blob.size());
2145 
2146   // Add the strings to the blob.
2147   for (const Metadata *MD : Strings)
2148     Blob.append(cast<MDString>(MD)->getString());
2149 
2150   // Emit the final record.
2151   Stream.EmitRecordWithBlob(createMetadataStringsAbbrev(), Record, Blob);
2152   Record.clear();
2153 }
2154 
2155 // Generates an enum to use as an index in the Abbrev array of Metadata record.
2156 enum MetadataAbbrev : unsigned {
2157 #define HANDLE_MDNODE_LEAF(CLASS) CLASS##AbbrevID,
2158 #include "llvm/IR/Metadata.def"
2159   LastPlusOne
2160 };
2161 
2162 void ModuleBitcodeWriter::writeMetadataRecords(
2163     ArrayRef<const Metadata *> MDs, SmallVectorImpl<uint64_t> &Record,
2164     std::vector<unsigned> *MDAbbrevs, std::vector<uint64_t> *IndexPos) {
2165   if (MDs.empty())
2166     return;
2167 
2168   // Initialize MDNode abbreviations.
2169 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
2170 #include "llvm/IR/Metadata.def"
2171 
2172   for (const Metadata *MD : MDs) {
2173     if (IndexPos)
2174       IndexPos->push_back(Stream.GetCurrentBitNo());
2175     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
2176       assert(N->isResolved() && "Expected forward references to be resolved");
2177 
2178       switch (N->getMetadataID()) {
2179       default:
2180         llvm_unreachable("Invalid MDNode subclass");
2181 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
2182   case Metadata::CLASS##Kind:                                                  \
2183     if (MDAbbrevs)                                                             \
2184       write##CLASS(cast<CLASS>(N), Record,                                     \
2185                    (*MDAbbrevs)[MetadataAbbrev::CLASS##AbbrevID]);             \
2186     else                                                                       \
2187       write##CLASS(cast<CLASS>(N), Record, CLASS##Abbrev);                     \
2188     continue;
2189 #include "llvm/IR/Metadata.def"
2190       }
2191     }
2192     writeValueAsMetadata(cast<ValueAsMetadata>(MD), Record);
2193   }
2194 }
2195 
2196 void ModuleBitcodeWriter::writeModuleMetadata() {
2197   if (!VE.hasMDs() && M.named_metadata_empty())
2198     return;
2199 
2200   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 4);
2201   SmallVector<uint64_t, 64> Record;
2202 
2203   // Emit all abbrevs upfront, so that the reader can jump in the middle of the
2204   // block and load any metadata.
2205   std::vector<unsigned> MDAbbrevs;
2206 
2207   MDAbbrevs.resize(MetadataAbbrev::LastPlusOne);
2208   MDAbbrevs[MetadataAbbrev::DILocationAbbrevID] = createDILocationAbbrev();
2209   MDAbbrevs[MetadataAbbrev::GenericDINodeAbbrevID] =
2210       createGenericDINodeAbbrev();
2211 
2212   auto Abbv = std::make_shared<BitCodeAbbrev>();
2213   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX_OFFSET));
2214   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2215   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2216   unsigned OffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2217 
2218   Abbv = std::make_shared<BitCodeAbbrev>();
2219   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX));
2220   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2221   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2222   unsigned IndexAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2223 
2224   // Emit MDStrings together upfront.
2225   writeMetadataStrings(VE.getMDStrings(), Record);
2226 
2227   // We only emit an index for the metadata record if we have more than a given
2228   // (naive) threshold of metadatas, otherwise it is not worth it.
2229   if (VE.getNonMDStrings().size() > IndexThreshold) {
2230     // Write a placeholder value in for the offset of the metadata index,
2231     // which is written after the records, so that it can include
2232     // the offset of each entry. The placeholder offset will be
2233     // updated after all records are emitted.
2234     uint64_t Vals[] = {0, 0};
2235     Stream.EmitRecord(bitc::METADATA_INDEX_OFFSET, Vals, OffsetAbbrev);
2236   }
2237 
2238   // Compute and save the bit offset to the current position, which will be
2239   // patched when we emit the index later. We can simply subtract the 64-bit
2240   // fixed size from the current bit number to get the location to backpatch.
2241   uint64_t IndexOffsetRecordBitPos = Stream.GetCurrentBitNo();
2242 
2243   // This index will contain the bitpos for each individual record.
2244   std::vector<uint64_t> IndexPos;
2245   IndexPos.reserve(VE.getNonMDStrings().size());
2246 
2247   // Write all the records
2248   writeMetadataRecords(VE.getNonMDStrings(), Record, &MDAbbrevs, &IndexPos);
2249 
2250   if (VE.getNonMDStrings().size() > IndexThreshold) {
2251     // Now that we have emitted all the records we will emit the index. But
2252     // first
2253     // backpatch the forward reference so that the reader can skip the records
2254     // efficiently.
2255     Stream.BackpatchWord64(IndexOffsetRecordBitPos - 64,
2256                            Stream.GetCurrentBitNo() - IndexOffsetRecordBitPos);
2257 
2258     // Delta encode the index.
2259     uint64_t PreviousValue = IndexOffsetRecordBitPos;
2260     for (auto &Elt : IndexPos) {
2261       auto EltDelta = Elt - PreviousValue;
2262       PreviousValue = Elt;
2263       Elt = EltDelta;
2264     }
2265     // Emit the index record.
2266     Stream.EmitRecord(bitc::METADATA_INDEX, IndexPos, IndexAbbrev);
2267     IndexPos.clear();
2268   }
2269 
2270   // Write the named metadata now.
2271   writeNamedMetadata(Record);
2272 
2273   auto AddDeclAttachedMetadata = [&](const GlobalObject &GO) {
2274     SmallVector<uint64_t, 4> Record;
2275     Record.push_back(VE.getValueID(&GO));
2276     pushGlobalMetadataAttachment(Record, GO);
2277     Stream.EmitRecord(bitc::METADATA_GLOBAL_DECL_ATTACHMENT, Record);
2278   };
2279   for (const Function &F : M)
2280     if (F.isDeclaration() && F.hasMetadata())
2281       AddDeclAttachedMetadata(F);
2282   // FIXME: Only store metadata for declarations here, and move data for global
2283   // variable definitions to a separate block (PR28134).
2284   for (const GlobalVariable &GV : M.globals())
2285     if (GV.hasMetadata())
2286       AddDeclAttachedMetadata(GV);
2287 
2288   Stream.ExitBlock();
2289 }
2290 
2291 void ModuleBitcodeWriter::writeFunctionMetadata(const Function &F) {
2292   if (!VE.hasMDs())
2293     return;
2294 
2295   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
2296   SmallVector<uint64_t, 64> Record;
2297   writeMetadataStrings(VE.getMDStrings(), Record);
2298   writeMetadataRecords(VE.getNonMDStrings(), Record);
2299   Stream.ExitBlock();
2300 }
2301 
2302 void ModuleBitcodeWriter::pushGlobalMetadataAttachment(
2303     SmallVectorImpl<uint64_t> &Record, const GlobalObject &GO) {
2304   // [n x [id, mdnode]]
2305   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2306   GO.getAllMetadata(MDs);
2307   for (const auto &I : MDs) {
2308     Record.push_back(I.first);
2309     Record.push_back(VE.getMetadataID(I.second));
2310   }
2311 }
2312 
2313 void ModuleBitcodeWriter::writeFunctionMetadataAttachment(const Function &F) {
2314   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
2315 
2316   SmallVector<uint64_t, 64> Record;
2317 
2318   if (F.hasMetadata()) {
2319     pushGlobalMetadataAttachment(Record, F);
2320     Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2321     Record.clear();
2322   }
2323 
2324   // Write metadata attachments
2325   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
2326   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2327   for (const BasicBlock &BB : F)
2328     for (const Instruction &I : BB) {
2329       MDs.clear();
2330       I.getAllMetadataOtherThanDebugLoc(MDs);
2331 
2332       // If no metadata, ignore instruction.
2333       if (MDs.empty()) continue;
2334 
2335       Record.push_back(VE.getInstructionID(&I));
2336 
2337       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
2338         Record.push_back(MDs[i].first);
2339         Record.push_back(VE.getMetadataID(MDs[i].second));
2340       }
2341       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2342       Record.clear();
2343     }
2344 
2345   Stream.ExitBlock();
2346 }
2347 
2348 void ModuleBitcodeWriter::writeModuleMetadataKinds() {
2349   SmallVector<uint64_t, 64> Record;
2350 
2351   // Write metadata kinds
2352   // METADATA_KIND - [n x [id, name]]
2353   SmallVector<StringRef, 8> Names;
2354   M.getMDKindNames(Names);
2355 
2356   if (Names.empty()) return;
2357 
2358   Stream.EnterSubblock(bitc::METADATA_KIND_BLOCK_ID, 3);
2359 
2360   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
2361     Record.push_back(MDKindID);
2362     StringRef KName = Names[MDKindID];
2363     Record.append(KName.begin(), KName.end());
2364 
2365     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
2366     Record.clear();
2367   }
2368 
2369   Stream.ExitBlock();
2370 }
2371 
2372 void ModuleBitcodeWriter::writeOperandBundleTags() {
2373   // Write metadata kinds
2374   //
2375   // OPERAND_BUNDLE_TAGS_BLOCK_ID : N x OPERAND_BUNDLE_TAG
2376   //
2377   // OPERAND_BUNDLE_TAG - [strchr x N]
2378 
2379   SmallVector<StringRef, 8> Tags;
2380   M.getOperandBundleTags(Tags);
2381 
2382   if (Tags.empty())
2383     return;
2384 
2385   Stream.EnterSubblock(bitc::OPERAND_BUNDLE_TAGS_BLOCK_ID, 3);
2386 
2387   SmallVector<uint64_t, 64> Record;
2388 
2389   for (auto Tag : Tags) {
2390     Record.append(Tag.begin(), Tag.end());
2391 
2392     Stream.EmitRecord(bitc::OPERAND_BUNDLE_TAG, Record, 0);
2393     Record.clear();
2394   }
2395 
2396   Stream.ExitBlock();
2397 }
2398 
2399 void ModuleBitcodeWriter::writeSyncScopeNames() {
2400   SmallVector<StringRef, 8> SSNs;
2401   M.getContext().getSyncScopeNames(SSNs);
2402   if (SSNs.empty())
2403     return;
2404 
2405   Stream.EnterSubblock(bitc::SYNC_SCOPE_NAMES_BLOCK_ID, 2);
2406 
2407   SmallVector<uint64_t, 64> Record;
2408   for (auto SSN : SSNs) {
2409     Record.append(SSN.begin(), SSN.end());
2410     Stream.EmitRecord(bitc::SYNC_SCOPE_NAME, Record, 0);
2411     Record.clear();
2412   }
2413 
2414   Stream.ExitBlock();
2415 }
2416 
2417 void ModuleBitcodeWriter::writeConstants(unsigned FirstVal, unsigned LastVal,
2418                                          bool isGlobal) {
2419   if (FirstVal == LastVal) return;
2420 
2421   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
2422 
2423   unsigned AggregateAbbrev = 0;
2424   unsigned String8Abbrev = 0;
2425   unsigned CString7Abbrev = 0;
2426   unsigned CString6Abbrev = 0;
2427   // If this is a constant pool for the module, emit module-specific abbrevs.
2428   if (isGlobal) {
2429     // Abbrev for CST_CODE_AGGREGATE.
2430     auto Abbv = std::make_shared<BitCodeAbbrev>();
2431     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
2432     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2433     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
2434     AggregateAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2435 
2436     // Abbrev for CST_CODE_STRING.
2437     Abbv = std::make_shared<BitCodeAbbrev>();
2438     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
2439     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2440     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2441     String8Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2442     // Abbrev for CST_CODE_CSTRING.
2443     Abbv = std::make_shared<BitCodeAbbrev>();
2444     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2445     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2446     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2447     CString7Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2448     // Abbrev for CST_CODE_CSTRING.
2449     Abbv = std::make_shared<BitCodeAbbrev>();
2450     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2451     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2452     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2453     CString6Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2454   }
2455 
2456   SmallVector<uint64_t, 64> Record;
2457 
2458   const ValueEnumerator::ValueList &Vals = VE.getValues();
2459   Type *LastTy = nullptr;
2460   for (unsigned i = FirstVal; i != LastVal; ++i) {
2461     const Value *V = Vals[i].first;
2462     // If we need to switch types, do so now.
2463     if (V->getType() != LastTy) {
2464       LastTy = V->getType();
2465       Record.push_back(VE.getTypeID(LastTy));
2466       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
2467                         CONSTANTS_SETTYPE_ABBREV);
2468       Record.clear();
2469     }
2470 
2471     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
2472       Record.push_back(VE.getTypeID(IA->getFunctionType()));
2473       Record.push_back(
2474           unsigned(IA->hasSideEffects()) | unsigned(IA->isAlignStack()) << 1 |
2475           unsigned(IA->getDialect() & 1) << 2 | unsigned(IA->canThrow()) << 3);
2476 
2477       // Add the asm string.
2478       const std::string &AsmStr = IA->getAsmString();
2479       Record.push_back(AsmStr.size());
2480       Record.append(AsmStr.begin(), AsmStr.end());
2481 
2482       // Add the constraint string.
2483       const std::string &ConstraintStr = IA->getConstraintString();
2484       Record.push_back(ConstraintStr.size());
2485       Record.append(ConstraintStr.begin(), ConstraintStr.end());
2486       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
2487       Record.clear();
2488       continue;
2489     }
2490     const Constant *C = cast<Constant>(V);
2491     unsigned Code = -1U;
2492     unsigned AbbrevToUse = 0;
2493     if (C->isNullValue()) {
2494       Code = bitc::CST_CODE_NULL;
2495     } else if (isa<PoisonValue>(C)) {
2496       Code = bitc::CST_CODE_POISON;
2497     } else if (isa<UndefValue>(C)) {
2498       Code = bitc::CST_CODE_UNDEF;
2499     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
2500       if (IV->getBitWidth() <= 64) {
2501         uint64_t V = IV->getSExtValue();
2502         emitSignedInt64(Record, V);
2503         Code = bitc::CST_CODE_INTEGER;
2504         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
2505       } else {                             // Wide integers, > 64 bits in size.
2506         emitWideAPInt(Record, IV->getValue());
2507         Code = bitc::CST_CODE_WIDE_INTEGER;
2508       }
2509     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
2510       Code = bitc::CST_CODE_FLOAT;
2511       Type *Ty = CFP->getType();
2512       if (Ty->isHalfTy() || Ty->isBFloatTy() || Ty->isFloatTy() ||
2513           Ty->isDoubleTy()) {
2514         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
2515       } else if (Ty->isX86_FP80Ty()) {
2516         // api needed to prevent premature destruction
2517         // bits are not in the same order as a normal i80 APInt, compensate.
2518         APInt api = CFP->getValueAPF().bitcastToAPInt();
2519         const uint64_t *p = api.getRawData();
2520         Record.push_back((p[1] << 48) | (p[0] >> 16));
2521         Record.push_back(p[0] & 0xffffLL);
2522       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
2523         APInt api = CFP->getValueAPF().bitcastToAPInt();
2524         const uint64_t *p = api.getRawData();
2525         Record.push_back(p[0]);
2526         Record.push_back(p[1]);
2527       } else {
2528         assert(0 && "Unknown FP type!");
2529       }
2530     } else if (isa<ConstantDataSequential>(C) &&
2531                cast<ConstantDataSequential>(C)->isString()) {
2532       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
2533       // Emit constant strings specially.
2534       unsigned NumElts = Str->getNumElements();
2535       // If this is a null-terminated string, use the denser CSTRING encoding.
2536       if (Str->isCString()) {
2537         Code = bitc::CST_CODE_CSTRING;
2538         --NumElts;  // Don't encode the null, which isn't allowed by char6.
2539       } else {
2540         Code = bitc::CST_CODE_STRING;
2541         AbbrevToUse = String8Abbrev;
2542       }
2543       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
2544       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
2545       for (unsigned i = 0; i != NumElts; ++i) {
2546         unsigned char V = Str->getElementAsInteger(i);
2547         Record.push_back(V);
2548         isCStr7 &= (V & 128) == 0;
2549         if (isCStrChar6)
2550           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
2551       }
2552 
2553       if (isCStrChar6)
2554         AbbrevToUse = CString6Abbrev;
2555       else if (isCStr7)
2556         AbbrevToUse = CString7Abbrev;
2557     } else if (const ConstantDataSequential *CDS =
2558                   dyn_cast<ConstantDataSequential>(C)) {
2559       Code = bitc::CST_CODE_DATA;
2560       Type *EltTy = CDS->getElementType();
2561       if (isa<IntegerType>(EltTy)) {
2562         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2563           Record.push_back(CDS->getElementAsInteger(i));
2564       } else {
2565         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2566           Record.push_back(
2567               CDS->getElementAsAPFloat(i).bitcastToAPInt().getLimitedValue());
2568       }
2569     } else if (isa<ConstantAggregate>(C)) {
2570       Code = bitc::CST_CODE_AGGREGATE;
2571       for (const Value *Op : C->operands())
2572         Record.push_back(VE.getValueID(Op));
2573       AbbrevToUse = AggregateAbbrev;
2574     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
2575       switch (CE->getOpcode()) {
2576       default:
2577         if (Instruction::isCast(CE->getOpcode())) {
2578           Code = bitc::CST_CODE_CE_CAST;
2579           Record.push_back(getEncodedCastOpcode(CE->getOpcode()));
2580           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2581           Record.push_back(VE.getValueID(C->getOperand(0)));
2582           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
2583         } else {
2584           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
2585           Code = bitc::CST_CODE_CE_BINOP;
2586           Record.push_back(getEncodedBinaryOpcode(CE->getOpcode()));
2587           Record.push_back(VE.getValueID(C->getOperand(0)));
2588           Record.push_back(VE.getValueID(C->getOperand(1)));
2589           uint64_t Flags = getOptimizationFlags(CE);
2590           if (Flags != 0)
2591             Record.push_back(Flags);
2592         }
2593         break;
2594       case Instruction::FNeg: {
2595         assert(CE->getNumOperands() == 1 && "Unknown constant expr!");
2596         Code = bitc::CST_CODE_CE_UNOP;
2597         Record.push_back(getEncodedUnaryOpcode(CE->getOpcode()));
2598         Record.push_back(VE.getValueID(C->getOperand(0)));
2599         uint64_t Flags = getOptimizationFlags(CE);
2600         if (Flags != 0)
2601           Record.push_back(Flags);
2602         break;
2603       }
2604       case Instruction::GetElementPtr: {
2605         Code = bitc::CST_CODE_CE_GEP;
2606         const auto *GO = cast<GEPOperator>(C);
2607         Record.push_back(VE.getTypeID(GO->getSourceElementType()));
2608         if (Optional<unsigned> Idx = GO->getInRangeIndex()) {
2609           Code = bitc::CST_CODE_CE_GEP_WITH_INRANGE_INDEX;
2610           Record.push_back((*Idx << 1) | GO->isInBounds());
2611         } else if (GO->isInBounds())
2612           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
2613         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
2614           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
2615           Record.push_back(VE.getValueID(C->getOperand(i)));
2616         }
2617         break;
2618       }
2619       case Instruction::Select:
2620         Code = bitc::CST_CODE_CE_SELECT;
2621         Record.push_back(VE.getValueID(C->getOperand(0)));
2622         Record.push_back(VE.getValueID(C->getOperand(1)));
2623         Record.push_back(VE.getValueID(C->getOperand(2)));
2624         break;
2625       case Instruction::ExtractElement:
2626         Code = bitc::CST_CODE_CE_EXTRACTELT;
2627         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2628         Record.push_back(VE.getValueID(C->getOperand(0)));
2629         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
2630         Record.push_back(VE.getValueID(C->getOperand(1)));
2631         break;
2632       case Instruction::InsertElement:
2633         Code = bitc::CST_CODE_CE_INSERTELT;
2634         Record.push_back(VE.getValueID(C->getOperand(0)));
2635         Record.push_back(VE.getValueID(C->getOperand(1)));
2636         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
2637         Record.push_back(VE.getValueID(C->getOperand(2)));
2638         break;
2639       case Instruction::ShuffleVector:
2640         // If the return type and argument types are the same, this is a
2641         // standard shufflevector instruction.  If the types are different,
2642         // then the shuffle is widening or truncating the input vectors, and
2643         // the argument type must also be encoded.
2644         if (C->getType() == C->getOperand(0)->getType()) {
2645           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
2646         } else {
2647           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
2648           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2649         }
2650         Record.push_back(VE.getValueID(C->getOperand(0)));
2651         Record.push_back(VE.getValueID(C->getOperand(1)));
2652         Record.push_back(VE.getValueID(CE->getShuffleMaskForBitcode()));
2653         break;
2654       case Instruction::ICmp:
2655       case Instruction::FCmp:
2656         Code = bitc::CST_CODE_CE_CMP;
2657         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2658         Record.push_back(VE.getValueID(C->getOperand(0)));
2659         Record.push_back(VE.getValueID(C->getOperand(1)));
2660         Record.push_back(CE->getPredicate());
2661         break;
2662       case Instruction::ExtractValue:
2663       case Instruction::InsertValue:
2664         report_fatal_error("extractvalue/insertvalue constexprs not supported");
2665         break;
2666       }
2667     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
2668       Code = bitc::CST_CODE_BLOCKADDRESS;
2669       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
2670       Record.push_back(VE.getValueID(BA->getFunction()));
2671       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
2672     } else if (const auto *Equiv = dyn_cast<DSOLocalEquivalent>(C)) {
2673       Code = bitc::CST_CODE_DSO_LOCAL_EQUIVALENT;
2674       Record.push_back(VE.getTypeID(Equiv->getGlobalValue()->getType()));
2675       Record.push_back(VE.getValueID(Equiv->getGlobalValue()));
2676     } else if (const auto *NC = dyn_cast<NoCFIValue>(C)) {
2677       Code = bitc::CST_CODE_NO_CFI_VALUE;
2678       Record.push_back(VE.getTypeID(NC->getGlobalValue()->getType()));
2679       Record.push_back(VE.getValueID(NC->getGlobalValue()));
2680     } else {
2681 #ifndef NDEBUG
2682       C->dump();
2683 #endif
2684       llvm_unreachable("Unknown constant!");
2685     }
2686     Stream.EmitRecord(Code, Record, AbbrevToUse);
2687     Record.clear();
2688   }
2689 
2690   Stream.ExitBlock();
2691 }
2692 
2693 void ModuleBitcodeWriter::writeModuleConstants() {
2694   const ValueEnumerator::ValueList &Vals = VE.getValues();
2695 
2696   // Find the first constant to emit, which is the first non-globalvalue value.
2697   // We know globalvalues have been emitted by WriteModuleInfo.
2698   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
2699     if (!isa<GlobalValue>(Vals[i].first)) {
2700       writeConstants(i, Vals.size(), true);
2701       return;
2702     }
2703   }
2704 }
2705 
2706 /// pushValueAndType - The file has to encode both the value and type id for
2707 /// many values, because we need to know what type to create for forward
2708 /// references.  However, most operands are not forward references, so this type
2709 /// field is not needed.
2710 ///
2711 /// This function adds V's value ID to Vals.  If the value ID is higher than the
2712 /// instruction ID, then it is a forward reference, and it also includes the
2713 /// type ID.  The value ID that is written is encoded relative to the InstID.
2714 bool ModuleBitcodeWriter::pushValueAndType(const Value *V, unsigned InstID,
2715                                            SmallVectorImpl<unsigned> &Vals) {
2716   unsigned ValID = VE.getValueID(V);
2717   // Make encoding relative to the InstID.
2718   Vals.push_back(InstID - ValID);
2719   if (ValID >= InstID) {
2720     Vals.push_back(VE.getTypeID(V->getType()));
2721     return true;
2722   }
2723   return false;
2724 }
2725 
2726 void ModuleBitcodeWriter::writeOperandBundles(const CallBase &CS,
2727                                               unsigned InstID) {
2728   SmallVector<unsigned, 64> Record;
2729   LLVMContext &C = CS.getContext();
2730 
2731   for (unsigned i = 0, e = CS.getNumOperandBundles(); i != e; ++i) {
2732     const auto &Bundle = CS.getOperandBundleAt(i);
2733     Record.push_back(C.getOperandBundleTagID(Bundle.getTagName()));
2734 
2735     for (auto &Input : Bundle.Inputs)
2736       pushValueAndType(Input, InstID, Record);
2737 
2738     Stream.EmitRecord(bitc::FUNC_CODE_OPERAND_BUNDLE, Record);
2739     Record.clear();
2740   }
2741 }
2742 
2743 /// pushValue - Like pushValueAndType, but where the type of the value is
2744 /// omitted (perhaps it was already encoded in an earlier operand).
2745 void ModuleBitcodeWriter::pushValue(const Value *V, unsigned InstID,
2746                                     SmallVectorImpl<unsigned> &Vals) {
2747   unsigned ValID = VE.getValueID(V);
2748   Vals.push_back(InstID - ValID);
2749 }
2750 
2751 void ModuleBitcodeWriter::pushValueSigned(const Value *V, unsigned InstID,
2752                                           SmallVectorImpl<uint64_t> &Vals) {
2753   unsigned ValID = VE.getValueID(V);
2754   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
2755   emitSignedInt64(Vals, diff);
2756 }
2757 
2758 /// WriteInstruction - Emit an instruction to the specified stream.
2759 void ModuleBitcodeWriter::writeInstruction(const Instruction &I,
2760                                            unsigned InstID,
2761                                            SmallVectorImpl<unsigned> &Vals) {
2762   unsigned Code = 0;
2763   unsigned AbbrevToUse = 0;
2764   VE.setInstructionID(&I);
2765   switch (I.getOpcode()) {
2766   default:
2767     if (Instruction::isCast(I.getOpcode())) {
2768       Code = bitc::FUNC_CODE_INST_CAST;
2769       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2770         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
2771       Vals.push_back(VE.getTypeID(I.getType()));
2772       Vals.push_back(getEncodedCastOpcode(I.getOpcode()));
2773     } else {
2774       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
2775       Code = bitc::FUNC_CODE_INST_BINOP;
2776       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2777         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
2778       pushValue(I.getOperand(1), InstID, Vals);
2779       Vals.push_back(getEncodedBinaryOpcode(I.getOpcode()));
2780       uint64_t Flags = getOptimizationFlags(&I);
2781       if (Flags != 0) {
2782         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
2783           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
2784         Vals.push_back(Flags);
2785       }
2786     }
2787     break;
2788   case Instruction::FNeg: {
2789     Code = bitc::FUNC_CODE_INST_UNOP;
2790     if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2791       AbbrevToUse = FUNCTION_INST_UNOP_ABBREV;
2792     Vals.push_back(getEncodedUnaryOpcode(I.getOpcode()));
2793     uint64_t Flags = getOptimizationFlags(&I);
2794     if (Flags != 0) {
2795       if (AbbrevToUse == FUNCTION_INST_UNOP_ABBREV)
2796         AbbrevToUse = FUNCTION_INST_UNOP_FLAGS_ABBREV;
2797       Vals.push_back(Flags);
2798     }
2799     break;
2800   }
2801   case Instruction::GetElementPtr: {
2802     Code = bitc::FUNC_CODE_INST_GEP;
2803     AbbrevToUse = FUNCTION_INST_GEP_ABBREV;
2804     auto &GEPInst = cast<GetElementPtrInst>(I);
2805     Vals.push_back(GEPInst.isInBounds());
2806     Vals.push_back(VE.getTypeID(GEPInst.getSourceElementType()));
2807     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
2808       pushValueAndType(I.getOperand(i), InstID, Vals);
2809     break;
2810   }
2811   case Instruction::ExtractValue: {
2812     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
2813     pushValueAndType(I.getOperand(0), InstID, Vals);
2814     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
2815     Vals.append(EVI->idx_begin(), EVI->idx_end());
2816     break;
2817   }
2818   case Instruction::InsertValue: {
2819     Code = bitc::FUNC_CODE_INST_INSERTVAL;
2820     pushValueAndType(I.getOperand(0), InstID, Vals);
2821     pushValueAndType(I.getOperand(1), InstID, Vals);
2822     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
2823     Vals.append(IVI->idx_begin(), IVI->idx_end());
2824     break;
2825   }
2826   case Instruction::Select: {
2827     Code = bitc::FUNC_CODE_INST_VSELECT;
2828     pushValueAndType(I.getOperand(1), InstID, Vals);
2829     pushValue(I.getOperand(2), InstID, Vals);
2830     pushValueAndType(I.getOperand(0), InstID, Vals);
2831     uint64_t Flags = getOptimizationFlags(&I);
2832     if (Flags != 0)
2833       Vals.push_back(Flags);
2834     break;
2835   }
2836   case Instruction::ExtractElement:
2837     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
2838     pushValueAndType(I.getOperand(0), InstID, Vals);
2839     pushValueAndType(I.getOperand(1), InstID, Vals);
2840     break;
2841   case Instruction::InsertElement:
2842     Code = bitc::FUNC_CODE_INST_INSERTELT;
2843     pushValueAndType(I.getOperand(0), InstID, Vals);
2844     pushValue(I.getOperand(1), InstID, Vals);
2845     pushValueAndType(I.getOperand(2), InstID, Vals);
2846     break;
2847   case Instruction::ShuffleVector:
2848     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
2849     pushValueAndType(I.getOperand(0), InstID, Vals);
2850     pushValue(I.getOperand(1), InstID, Vals);
2851     pushValue(cast<ShuffleVectorInst>(I).getShuffleMaskForBitcode(), InstID,
2852               Vals);
2853     break;
2854   case Instruction::ICmp:
2855   case Instruction::FCmp: {
2856     // compare returning Int1Ty or vector of Int1Ty
2857     Code = bitc::FUNC_CODE_INST_CMP2;
2858     pushValueAndType(I.getOperand(0), InstID, Vals);
2859     pushValue(I.getOperand(1), InstID, Vals);
2860     Vals.push_back(cast<CmpInst>(I).getPredicate());
2861     uint64_t Flags = getOptimizationFlags(&I);
2862     if (Flags != 0)
2863       Vals.push_back(Flags);
2864     break;
2865   }
2866 
2867   case Instruction::Ret:
2868     {
2869       Code = bitc::FUNC_CODE_INST_RET;
2870       unsigned NumOperands = I.getNumOperands();
2871       if (NumOperands == 0)
2872         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
2873       else if (NumOperands == 1) {
2874         if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2875           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
2876       } else {
2877         for (unsigned i = 0, e = NumOperands; i != e; ++i)
2878           pushValueAndType(I.getOperand(i), InstID, Vals);
2879       }
2880     }
2881     break;
2882   case Instruction::Br:
2883     {
2884       Code = bitc::FUNC_CODE_INST_BR;
2885       const BranchInst &II = cast<BranchInst>(I);
2886       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
2887       if (II.isConditional()) {
2888         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
2889         pushValue(II.getCondition(), InstID, Vals);
2890       }
2891     }
2892     break;
2893   case Instruction::Switch:
2894     {
2895       Code = bitc::FUNC_CODE_INST_SWITCH;
2896       const SwitchInst &SI = cast<SwitchInst>(I);
2897       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
2898       pushValue(SI.getCondition(), InstID, Vals);
2899       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
2900       for (auto Case : SI.cases()) {
2901         Vals.push_back(VE.getValueID(Case.getCaseValue()));
2902         Vals.push_back(VE.getValueID(Case.getCaseSuccessor()));
2903       }
2904     }
2905     break;
2906   case Instruction::IndirectBr:
2907     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
2908     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2909     // Encode the address operand as relative, but not the basic blocks.
2910     pushValue(I.getOperand(0), InstID, Vals);
2911     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
2912       Vals.push_back(VE.getValueID(I.getOperand(i)));
2913     break;
2914 
2915   case Instruction::Invoke: {
2916     const InvokeInst *II = cast<InvokeInst>(&I);
2917     const Value *Callee = II->getCalledOperand();
2918     FunctionType *FTy = II->getFunctionType();
2919 
2920     if (II->hasOperandBundles())
2921       writeOperandBundles(*II, InstID);
2922 
2923     Code = bitc::FUNC_CODE_INST_INVOKE;
2924 
2925     Vals.push_back(VE.getAttributeListID(II->getAttributes()));
2926     Vals.push_back(II->getCallingConv() | 1 << 13);
2927     Vals.push_back(VE.getValueID(II->getNormalDest()));
2928     Vals.push_back(VE.getValueID(II->getUnwindDest()));
2929     Vals.push_back(VE.getTypeID(FTy));
2930     pushValueAndType(Callee, InstID, Vals);
2931 
2932     // Emit value #'s for the fixed parameters.
2933     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
2934       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
2935 
2936     // Emit type/value pairs for varargs params.
2937     if (FTy->isVarArg()) {
2938       for (unsigned i = FTy->getNumParams(), e = II->arg_size(); i != e; ++i)
2939         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
2940     }
2941     break;
2942   }
2943   case Instruction::Resume:
2944     Code = bitc::FUNC_CODE_INST_RESUME;
2945     pushValueAndType(I.getOperand(0), InstID, Vals);
2946     break;
2947   case Instruction::CleanupRet: {
2948     Code = bitc::FUNC_CODE_INST_CLEANUPRET;
2949     const auto &CRI = cast<CleanupReturnInst>(I);
2950     pushValue(CRI.getCleanupPad(), InstID, Vals);
2951     if (CRI.hasUnwindDest())
2952       Vals.push_back(VE.getValueID(CRI.getUnwindDest()));
2953     break;
2954   }
2955   case Instruction::CatchRet: {
2956     Code = bitc::FUNC_CODE_INST_CATCHRET;
2957     const auto &CRI = cast<CatchReturnInst>(I);
2958     pushValue(CRI.getCatchPad(), InstID, Vals);
2959     Vals.push_back(VE.getValueID(CRI.getSuccessor()));
2960     break;
2961   }
2962   case Instruction::CleanupPad:
2963   case Instruction::CatchPad: {
2964     const auto &FuncletPad = cast<FuncletPadInst>(I);
2965     Code = isa<CatchPadInst>(FuncletPad) ? bitc::FUNC_CODE_INST_CATCHPAD
2966                                          : bitc::FUNC_CODE_INST_CLEANUPPAD;
2967     pushValue(FuncletPad.getParentPad(), InstID, Vals);
2968 
2969     unsigned NumArgOperands = FuncletPad.getNumArgOperands();
2970     Vals.push_back(NumArgOperands);
2971     for (unsigned Op = 0; Op != NumArgOperands; ++Op)
2972       pushValueAndType(FuncletPad.getArgOperand(Op), InstID, Vals);
2973     break;
2974   }
2975   case Instruction::CatchSwitch: {
2976     Code = bitc::FUNC_CODE_INST_CATCHSWITCH;
2977     const auto &CatchSwitch = cast<CatchSwitchInst>(I);
2978 
2979     pushValue(CatchSwitch.getParentPad(), InstID, Vals);
2980 
2981     unsigned NumHandlers = CatchSwitch.getNumHandlers();
2982     Vals.push_back(NumHandlers);
2983     for (const BasicBlock *CatchPadBB : CatchSwitch.handlers())
2984       Vals.push_back(VE.getValueID(CatchPadBB));
2985 
2986     if (CatchSwitch.hasUnwindDest())
2987       Vals.push_back(VE.getValueID(CatchSwitch.getUnwindDest()));
2988     break;
2989   }
2990   case Instruction::CallBr: {
2991     const CallBrInst *CBI = cast<CallBrInst>(&I);
2992     const Value *Callee = CBI->getCalledOperand();
2993     FunctionType *FTy = CBI->getFunctionType();
2994 
2995     if (CBI->hasOperandBundles())
2996       writeOperandBundles(*CBI, InstID);
2997 
2998     Code = bitc::FUNC_CODE_INST_CALLBR;
2999 
3000     Vals.push_back(VE.getAttributeListID(CBI->getAttributes()));
3001 
3002     Vals.push_back(CBI->getCallingConv() << bitc::CALL_CCONV |
3003                    1 << bitc::CALL_EXPLICIT_TYPE);
3004 
3005     Vals.push_back(VE.getValueID(CBI->getDefaultDest()));
3006     Vals.push_back(CBI->getNumIndirectDests());
3007     for (unsigned i = 0, e = CBI->getNumIndirectDests(); i != e; ++i)
3008       Vals.push_back(VE.getValueID(CBI->getIndirectDest(i)));
3009 
3010     Vals.push_back(VE.getTypeID(FTy));
3011     pushValueAndType(Callee, InstID, Vals);
3012 
3013     // Emit value #'s for the fixed parameters.
3014     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
3015       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
3016 
3017     // Emit type/value pairs for varargs params.
3018     if (FTy->isVarArg()) {
3019       for (unsigned i = FTy->getNumParams(), e = CBI->arg_size(); i != e; ++i)
3020         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
3021     }
3022     break;
3023   }
3024   case Instruction::Unreachable:
3025     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
3026     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
3027     break;
3028 
3029   case Instruction::PHI: {
3030     const PHINode &PN = cast<PHINode>(I);
3031     Code = bitc::FUNC_CODE_INST_PHI;
3032     // With the newer instruction encoding, forward references could give
3033     // negative valued IDs.  This is most common for PHIs, so we use
3034     // signed VBRs.
3035     SmallVector<uint64_t, 128> Vals64;
3036     Vals64.push_back(VE.getTypeID(PN.getType()));
3037     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
3038       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64);
3039       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
3040     }
3041 
3042     uint64_t Flags = getOptimizationFlags(&I);
3043     if (Flags != 0)
3044       Vals64.push_back(Flags);
3045 
3046     // Emit a Vals64 vector and exit.
3047     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
3048     Vals64.clear();
3049     return;
3050   }
3051 
3052   case Instruction::LandingPad: {
3053     const LandingPadInst &LP = cast<LandingPadInst>(I);
3054     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
3055     Vals.push_back(VE.getTypeID(LP.getType()));
3056     Vals.push_back(LP.isCleanup());
3057     Vals.push_back(LP.getNumClauses());
3058     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
3059       if (LP.isCatch(I))
3060         Vals.push_back(LandingPadInst::Catch);
3061       else
3062         Vals.push_back(LandingPadInst::Filter);
3063       pushValueAndType(LP.getClause(I), InstID, Vals);
3064     }
3065     break;
3066   }
3067 
3068   case Instruction::Alloca: {
3069     Code = bitc::FUNC_CODE_INST_ALLOCA;
3070     const AllocaInst &AI = cast<AllocaInst>(I);
3071     Vals.push_back(VE.getTypeID(AI.getAllocatedType()));
3072     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
3073     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
3074     using APV = AllocaPackedValues;
3075     unsigned Record = 0;
3076     unsigned EncodedAlign = getEncodedAlign(AI.getAlign());
3077     Bitfield::set<APV::AlignLower>(
3078         Record, EncodedAlign & ((1 << APV::AlignLower::Bits) - 1));
3079     Bitfield::set<APV::AlignUpper>(Record,
3080                                    EncodedAlign >> APV::AlignLower::Bits);
3081     Bitfield::set<APV::UsedWithInAlloca>(Record, AI.isUsedWithInAlloca());
3082     Bitfield::set<APV::ExplicitType>(Record, true);
3083     Bitfield::set<APV::SwiftError>(Record, AI.isSwiftError());
3084     Vals.push_back(Record);
3085 
3086     unsigned AS = AI.getAddressSpace();
3087     if (AS != M.getDataLayout().getAllocaAddrSpace())
3088       Vals.push_back(AS);
3089     break;
3090   }
3091 
3092   case Instruction::Load:
3093     if (cast<LoadInst>(I).isAtomic()) {
3094       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
3095       pushValueAndType(I.getOperand(0), InstID, Vals);
3096     } else {
3097       Code = bitc::FUNC_CODE_INST_LOAD;
3098       if (!pushValueAndType(I.getOperand(0), InstID, Vals)) // ptr
3099         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
3100     }
3101     Vals.push_back(VE.getTypeID(I.getType()));
3102     Vals.push_back(getEncodedAlign(cast<LoadInst>(I).getAlign()));
3103     Vals.push_back(cast<LoadInst>(I).isVolatile());
3104     if (cast<LoadInst>(I).isAtomic()) {
3105       Vals.push_back(getEncodedOrdering(cast<LoadInst>(I).getOrdering()));
3106       Vals.push_back(getEncodedSyncScopeID(cast<LoadInst>(I).getSyncScopeID()));
3107     }
3108     break;
3109   case Instruction::Store:
3110     if (cast<StoreInst>(I).isAtomic())
3111       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
3112     else
3113       Code = bitc::FUNC_CODE_INST_STORE;
3114     pushValueAndType(I.getOperand(1), InstID, Vals); // ptrty + ptr
3115     pushValueAndType(I.getOperand(0), InstID, Vals); // valty + val
3116     Vals.push_back(getEncodedAlign(cast<StoreInst>(I).getAlign()));
3117     Vals.push_back(cast<StoreInst>(I).isVolatile());
3118     if (cast<StoreInst>(I).isAtomic()) {
3119       Vals.push_back(getEncodedOrdering(cast<StoreInst>(I).getOrdering()));
3120       Vals.push_back(
3121           getEncodedSyncScopeID(cast<StoreInst>(I).getSyncScopeID()));
3122     }
3123     break;
3124   case Instruction::AtomicCmpXchg:
3125     Code = bitc::FUNC_CODE_INST_CMPXCHG;
3126     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
3127     pushValueAndType(I.getOperand(1), InstID, Vals); // cmp.
3128     pushValue(I.getOperand(2), InstID, Vals);        // newval.
3129     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
3130     Vals.push_back(
3131         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
3132     Vals.push_back(
3133         getEncodedSyncScopeID(cast<AtomicCmpXchgInst>(I).getSyncScopeID()));
3134     Vals.push_back(
3135         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
3136     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
3137     Vals.push_back(getEncodedAlign(cast<AtomicCmpXchgInst>(I).getAlign()));
3138     break;
3139   case Instruction::AtomicRMW:
3140     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
3141     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
3142     pushValueAndType(I.getOperand(1), InstID, Vals); // valty + val
3143     Vals.push_back(
3144         getEncodedRMWOperation(cast<AtomicRMWInst>(I).getOperation()));
3145     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
3146     Vals.push_back(getEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
3147     Vals.push_back(
3148         getEncodedSyncScopeID(cast<AtomicRMWInst>(I).getSyncScopeID()));
3149     Vals.push_back(getEncodedAlign(cast<AtomicRMWInst>(I).getAlign()));
3150     break;
3151   case Instruction::Fence:
3152     Code = bitc::FUNC_CODE_INST_FENCE;
3153     Vals.push_back(getEncodedOrdering(cast<FenceInst>(I).getOrdering()));
3154     Vals.push_back(getEncodedSyncScopeID(cast<FenceInst>(I).getSyncScopeID()));
3155     break;
3156   case Instruction::Call: {
3157     const CallInst &CI = cast<CallInst>(I);
3158     FunctionType *FTy = CI.getFunctionType();
3159 
3160     if (CI.hasOperandBundles())
3161       writeOperandBundles(CI, InstID);
3162 
3163     Code = bitc::FUNC_CODE_INST_CALL;
3164 
3165     Vals.push_back(VE.getAttributeListID(CI.getAttributes()));
3166 
3167     unsigned Flags = getOptimizationFlags(&I);
3168     Vals.push_back(CI.getCallingConv() << bitc::CALL_CCONV |
3169                    unsigned(CI.isTailCall()) << bitc::CALL_TAIL |
3170                    unsigned(CI.isMustTailCall()) << bitc::CALL_MUSTTAIL |
3171                    1 << bitc::CALL_EXPLICIT_TYPE |
3172                    unsigned(CI.isNoTailCall()) << bitc::CALL_NOTAIL |
3173                    unsigned(Flags != 0) << bitc::CALL_FMF);
3174     if (Flags != 0)
3175       Vals.push_back(Flags);
3176 
3177     Vals.push_back(VE.getTypeID(FTy));
3178     pushValueAndType(CI.getCalledOperand(), InstID, Vals); // Callee
3179 
3180     // Emit value #'s for the fixed parameters.
3181     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
3182       // Check for labels (can happen with asm labels).
3183       if (FTy->getParamType(i)->isLabelTy())
3184         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
3185       else
3186         pushValue(CI.getArgOperand(i), InstID, Vals); // fixed param.
3187     }
3188 
3189     // Emit type/value pairs for varargs params.
3190     if (FTy->isVarArg()) {
3191       for (unsigned i = FTy->getNumParams(), e = CI.arg_size(); i != e; ++i)
3192         pushValueAndType(CI.getArgOperand(i), InstID, Vals); // varargs
3193     }
3194     break;
3195   }
3196   case Instruction::VAArg:
3197     Code = bitc::FUNC_CODE_INST_VAARG;
3198     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
3199     pushValue(I.getOperand(0), InstID, Vals);                   // valist.
3200     Vals.push_back(VE.getTypeID(I.getType())); // restype.
3201     break;
3202   case Instruction::Freeze:
3203     Code = bitc::FUNC_CODE_INST_FREEZE;
3204     pushValueAndType(I.getOperand(0), InstID, Vals);
3205     break;
3206   }
3207 
3208   Stream.EmitRecord(Code, Vals, AbbrevToUse);
3209   Vals.clear();
3210 }
3211 
3212 /// Write a GlobalValue VST to the module. The purpose of this data structure is
3213 /// to allow clients to efficiently find the function body.
3214 void ModuleBitcodeWriter::writeGlobalValueSymbolTable(
3215   DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3216   // Get the offset of the VST we are writing, and backpatch it into
3217   // the VST forward declaration record.
3218   uint64_t VSTOffset = Stream.GetCurrentBitNo();
3219   // The BitcodeStartBit was the stream offset of the identification block.
3220   VSTOffset -= bitcodeStartBit();
3221   assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
3222   // Note that we add 1 here because the offset is relative to one word
3223   // before the start of the identification block, which was historically
3224   // always the start of the regular bitcode header.
3225   Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32 + 1);
3226 
3227   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3228 
3229   auto Abbv = std::make_shared<BitCodeAbbrev>();
3230   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
3231   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
3232   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
3233   unsigned FnEntryAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3234 
3235   for (const Function &F : M) {
3236     uint64_t Record[2];
3237 
3238     if (F.isDeclaration())
3239       continue;
3240 
3241     Record[0] = VE.getValueID(&F);
3242 
3243     // Save the word offset of the function (from the start of the
3244     // actual bitcode written to the stream).
3245     uint64_t BitcodeIndex = FunctionToBitcodeIndex[&F] - bitcodeStartBit();
3246     assert((BitcodeIndex & 31) == 0 && "function block not 32-bit aligned");
3247     // Note that we add 1 here because the offset is relative to one word
3248     // before the start of the identification block, which was historically
3249     // always the start of the regular bitcode header.
3250     Record[1] = BitcodeIndex / 32 + 1;
3251 
3252     Stream.EmitRecord(bitc::VST_CODE_FNENTRY, Record, FnEntryAbbrev);
3253   }
3254 
3255   Stream.ExitBlock();
3256 }
3257 
3258 /// Emit names for arguments, instructions and basic blocks in a function.
3259 void ModuleBitcodeWriter::writeFunctionLevelValueSymbolTable(
3260     const ValueSymbolTable &VST) {
3261   if (VST.empty())
3262     return;
3263 
3264   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3265 
3266   // FIXME: Set up the abbrev, we know how many values there are!
3267   // FIXME: We know if the type names can use 7-bit ascii.
3268   SmallVector<uint64_t, 64> NameVals;
3269 
3270   for (const ValueName &Name : VST) {
3271     // Figure out the encoding to use for the name.
3272     StringEncoding Bits = getStringEncoding(Name.getKey());
3273 
3274     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
3275     NameVals.push_back(VE.getValueID(Name.getValue()));
3276 
3277     // VST_CODE_ENTRY:   [valueid, namechar x N]
3278     // VST_CODE_BBENTRY: [bbid, namechar x N]
3279     unsigned Code;
3280     if (isa<BasicBlock>(Name.getValue())) {
3281       Code = bitc::VST_CODE_BBENTRY;
3282       if (Bits == SE_Char6)
3283         AbbrevToUse = VST_BBENTRY_6_ABBREV;
3284     } else {
3285       Code = bitc::VST_CODE_ENTRY;
3286       if (Bits == SE_Char6)
3287         AbbrevToUse = VST_ENTRY_6_ABBREV;
3288       else if (Bits == SE_Fixed7)
3289         AbbrevToUse = VST_ENTRY_7_ABBREV;
3290     }
3291 
3292     for (const auto P : Name.getKey())
3293       NameVals.push_back((unsigned char)P);
3294 
3295     // Emit the finished record.
3296     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
3297     NameVals.clear();
3298   }
3299 
3300   Stream.ExitBlock();
3301 }
3302 
3303 void ModuleBitcodeWriter::writeUseList(UseListOrder &&Order) {
3304   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
3305   unsigned Code;
3306   if (isa<BasicBlock>(Order.V))
3307     Code = bitc::USELIST_CODE_BB;
3308   else
3309     Code = bitc::USELIST_CODE_DEFAULT;
3310 
3311   SmallVector<uint64_t, 64> Record(Order.Shuffle.begin(), Order.Shuffle.end());
3312   Record.push_back(VE.getValueID(Order.V));
3313   Stream.EmitRecord(Code, Record);
3314 }
3315 
3316 void ModuleBitcodeWriter::writeUseListBlock(const Function *F) {
3317   assert(VE.shouldPreserveUseListOrder() &&
3318          "Expected to be preserving use-list order");
3319 
3320   auto hasMore = [&]() {
3321     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
3322   };
3323   if (!hasMore())
3324     // Nothing to do.
3325     return;
3326 
3327   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
3328   while (hasMore()) {
3329     writeUseList(std::move(VE.UseListOrders.back()));
3330     VE.UseListOrders.pop_back();
3331   }
3332   Stream.ExitBlock();
3333 }
3334 
3335 /// Emit a function body to the module stream.
3336 void ModuleBitcodeWriter::writeFunction(
3337     const Function &F,
3338     DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3339   // Save the bitcode index of the start of this function block for recording
3340   // in the VST.
3341   FunctionToBitcodeIndex[&F] = Stream.GetCurrentBitNo();
3342 
3343   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
3344   VE.incorporateFunction(F);
3345 
3346   SmallVector<unsigned, 64> Vals;
3347 
3348   // Emit the number of basic blocks, so the reader can create them ahead of
3349   // time.
3350   Vals.push_back(VE.getBasicBlocks().size());
3351   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
3352   Vals.clear();
3353 
3354   // If there are function-local constants, emit them now.
3355   unsigned CstStart, CstEnd;
3356   VE.getFunctionConstantRange(CstStart, CstEnd);
3357   writeConstants(CstStart, CstEnd, false);
3358 
3359   // If there is function-local metadata, emit it now.
3360   writeFunctionMetadata(F);
3361 
3362   // Keep a running idea of what the instruction ID is.
3363   unsigned InstID = CstEnd;
3364 
3365   bool NeedsMetadataAttachment = F.hasMetadata();
3366 
3367   DILocation *LastDL = nullptr;
3368   SmallPtrSet<Function *, 4> BlockAddressUsers;
3369 
3370   // Finally, emit all the instructions, in order.
3371   for (const BasicBlock &BB : F) {
3372     for (const Instruction &I : BB) {
3373       writeInstruction(I, InstID, Vals);
3374 
3375       if (!I.getType()->isVoidTy())
3376         ++InstID;
3377 
3378       // If the instruction has metadata, write a metadata attachment later.
3379       NeedsMetadataAttachment |= I.hasMetadataOtherThanDebugLoc();
3380 
3381       // If the instruction has a debug location, emit it.
3382       DILocation *DL = I.getDebugLoc();
3383       if (!DL)
3384         continue;
3385 
3386       if (DL == LastDL) {
3387         // Just repeat the same debug loc as last time.
3388         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
3389         continue;
3390       }
3391 
3392       Vals.push_back(DL->getLine());
3393       Vals.push_back(DL->getColumn());
3394       Vals.push_back(VE.getMetadataOrNullID(DL->getScope()));
3395       Vals.push_back(VE.getMetadataOrNullID(DL->getInlinedAt()));
3396       Vals.push_back(DL->isImplicitCode());
3397       Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
3398       Vals.clear();
3399 
3400       LastDL = DL;
3401     }
3402 
3403     if (BlockAddress *BA = BlockAddress::lookup(&BB)) {
3404       for (User *U : BA->users()) {
3405         if (auto *I = dyn_cast<Instruction>(U)) {
3406           Function *P = I->getParent()->getParent();
3407           if (P != &F)
3408             BlockAddressUsers.insert(P);
3409         }
3410       }
3411     }
3412   }
3413 
3414   if (!BlockAddressUsers.empty()) {
3415     SmallVector<uint64_t, 4> Record;
3416     Record.reserve(BlockAddressUsers.size());
3417     for (Function *F : BlockAddressUsers)
3418       Record.push_back(VE.getValueID(F));
3419     Stream.EmitRecord(bitc::FUNC_CODE_BLOCKADDR_USERS, Record);
3420   }
3421 
3422   // Emit names for all the instructions etc.
3423   if (auto *Symtab = F.getValueSymbolTable())
3424     writeFunctionLevelValueSymbolTable(*Symtab);
3425 
3426   if (NeedsMetadataAttachment)
3427     writeFunctionMetadataAttachment(F);
3428   if (VE.shouldPreserveUseListOrder())
3429     writeUseListBlock(&F);
3430   VE.purgeFunction();
3431   Stream.ExitBlock();
3432 }
3433 
3434 // Emit blockinfo, which defines the standard abbreviations etc.
3435 void ModuleBitcodeWriter::writeBlockInfo() {
3436   // We only want to emit block info records for blocks that have multiple
3437   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
3438   // Other blocks can define their abbrevs inline.
3439   Stream.EnterBlockInfoBlock();
3440 
3441   { // 8-bit fixed-width VST_CODE_ENTRY/VST_CODE_BBENTRY strings.
3442     auto Abbv = std::make_shared<BitCodeAbbrev>();
3443     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
3444     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3445     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3446     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3447     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3448         VST_ENTRY_8_ABBREV)
3449       llvm_unreachable("Unexpected abbrev ordering!");
3450   }
3451 
3452   { // 7-bit fixed width VST_CODE_ENTRY strings.
3453     auto Abbv = std::make_shared<BitCodeAbbrev>();
3454     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3455     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3456     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3457     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3458     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3459         VST_ENTRY_7_ABBREV)
3460       llvm_unreachable("Unexpected abbrev ordering!");
3461   }
3462   { // 6-bit char6 VST_CODE_ENTRY strings.
3463     auto Abbv = std::make_shared<BitCodeAbbrev>();
3464     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3465     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3466     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3467     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3468     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3469         VST_ENTRY_6_ABBREV)
3470       llvm_unreachable("Unexpected abbrev ordering!");
3471   }
3472   { // 6-bit char6 VST_CODE_BBENTRY strings.
3473     auto Abbv = std::make_shared<BitCodeAbbrev>();
3474     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
3475     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3476     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3477     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3478     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3479         VST_BBENTRY_6_ABBREV)
3480       llvm_unreachable("Unexpected abbrev ordering!");
3481   }
3482 
3483   { // SETTYPE abbrev for CONSTANTS_BLOCK.
3484     auto Abbv = std::make_shared<BitCodeAbbrev>();
3485     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
3486     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
3487                               VE.computeBitsRequiredForTypeIndicies()));
3488     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3489         CONSTANTS_SETTYPE_ABBREV)
3490       llvm_unreachable("Unexpected abbrev ordering!");
3491   }
3492 
3493   { // INTEGER abbrev for CONSTANTS_BLOCK.
3494     auto Abbv = std::make_shared<BitCodeAbbrev>();
3495     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
3496     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3497     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3498         CONSTANTS_INTEGER_ABBREV)
3499       llvm_unreachable("Unexpected abbrev ordering!");
3500   }
3501 
3502   { // CE_CAST abbrev for CONSTANTS_BLOCK.
3503     auto Abbv = std::make_shared<BitCodeAbbrev>();
3504     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
3505     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
3506     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
3507                               VE.computeBitsRequiredForTypeIndicies()));
3508     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
3509 
3510     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3511         CONSTANTS_CE_CAST_Abbrev)
3512       llvm_unreachable("Unexpected abbrev ordering!");
3513   }
3514   { // NULL abbrev for CONSTANTS_BLOCK.
3515     auto Abbv = std::make_shared<BitCodeAbbrev>();
3516     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
3517     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3518         CONSTANTS_NULL_Abbrev)
3519       llvm_unreachable("Unexpected abbrev ordering!");
3520   }
3521 
3522   // FIXME: This should only use space for first class types!
3523 
3524   { // INST_LOAD abbrev for FUNCTION_BLOCK.
3525     auto Abbv = std::make_shared<BitCodeAbbrev>();
3526     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
3527     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
3528     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
3529                               VE.computeBitsRequiredForTypeIndicies()));
3530     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
3531     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
3532     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3533         FUNCTION_INST_LOAD_ABBREV)
3534       llvm_unreachable("Unexpected abbrev ordering!");
3535   }
3536   { // INST_UNOP abbrev for FUNCTION_BLOCK.
3537     auto Abbv = std::make_shared<BitCodeAbbrev>();
3538     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3539     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3540     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3541     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3542         FUNCTION_INST_UNOP_ABBREV)
3543       llvm_unreachable("Unexpected abbrev ordering!");
3544   }
3545   { // INST_UNOP_FLAGS abbrev for FUNCTION_BLOCK.
3546     auto Abbv = std::make_shared<BitCodeAbbrev>();
3547     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3548     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3549     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3550     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3551     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3552         FUNCTION_INST_UNOP_FLAGS_ABBREV)
3553       llvm_unreachable("Unexpected abbrev ordering!");
3554   }
3555   { // INST_BINOP abbrev for FUNCTION_BLOCK.
3556     auto Abbv = std::make_shared<BitCodeAbbrev>();
3557     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3558     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3559     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3560     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3561     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3562         FUNCTION_INST_BINOP_ABBREV)
3563       llvm_unreachable("Unexpected abbrev ordering!");
3564   }
3565   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
3566     auto Abbv = std::make_shared<BitCodeAbbrev>();
3567     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3568     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3569     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3570     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3571     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3572     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3573         FUNCTION_INST_BINOP_FLAGS_ABBREV)
3574       llvm_unreachable("Unexpected abbrev ordering!");
3575   }
3576   { // INST_CAST abbrev for FUNCTION_BLOCK.
3577     auto Abbv = std::make_shared<BitCodeAbbrev>();
3578     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
3579     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
3580     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
3581                               VE.computeBitsRequiredForTypeIndicies()));
3582     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
3583     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3584         FUNCTION_INST_CAST_ABBREV)
3585       llvm_unreachable("Unexpected abbrev ordering!");
3586   }
3587 
3588   { // INST_RET abbrev for FUNCTION_BLOCK.
3589     auto Abbv = std::make_shared<BitCodeAbbrev>();
3590     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3591     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3592         FUNCTION_INST_RET_VOID_ABBREV)
3593       llvm_unreachable("Unexpected abbrev ordering!");
3594   }
3595   { // INST_RET abbrev for FUNCTION_BLOCK.
3596     auto Abbv = std::make_shared<BitCodeAbbrev>();
3597     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3598     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
3599     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3600         FUNCTION_INST_RET_VAL_ABBREV)
3601       llvm_unreachable("Unexpected abbrev ordering!");
3602   }
3603   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
3604     auto Abbv = std::make_shared<BitCodeAbbrev>();
3605     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
3606     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3607         FUNCTION_INST_UNREACHABLE_ABBREV)
3608       llvm_unreachable("Unexpected abbrev ordering!");
3609   }
3610   {
3611     auto Abbv = std::make_shared<BitCodeAbbrev>();
3612     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_GEP));
3613     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
3614     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, // dest ty
3615                               Log2_32_Ceil(VE.getTypes().size() + 1)));
3616     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3617     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
3618     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3619         FUNCTION_INST_GEP_ABBREV)
3620       llvm_unreachable("Unexpected abbrev ordering!");
3621   }
3622 
3623   Stream.ExitBlock();
3624 }
3625 
3626 /// Write the module path strings, currently only used when generating
3627 /// a combined index file.
3628 void IndexBitcodeWriter::writeModStrings() {
3629   Stream.EnterSubblock(bitc::MODULE_STRTAB_BLOCK_ID, 3);
3630 
3631   // TODO: See which abbrev sizes we actually need to emit
3632 
3633   // 8-bit fixed-width MST_ENTRY strings.
3634   auto Abbv = std::make_shared<BitCodeAbbrev>();
3635   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3636   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3637   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3638   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3639   unsigned Abbrev8Bit = Stream.EmitAbbrev(std::move(Abbv));
3640 
3641   // 7-bit fixed width MST_ENTRY strings.
3642   Abbv = std::make_shared<BitCodeAbbrev>();
3643   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3644   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3645   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3646   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3647   unsigned Abbrev7Bit = Stream.EmitAbbrev(std::move(Abbv));
3648 
3649   // 6-bit char6 MST_ENTRY strings.
3650   Abbv = std::make_shared<BitCodeAbbrev>();
3651   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3652   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3653   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3654   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3655   unsigned Abbrev6Bit = Stream.EmitAbbrev(std::move(Abbv));
3656 
3657   // Module Hash, 160 bits SHA1. Optionally, emitted after each MST_CODE_ENTRY.
3658   Abbv = std::make_shared<BitCodeAbbrev>();
3659   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_HASH));
3660   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3661   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3662   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3663   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3664   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3665   unsigned AbbrevHash = Stream.EmitAbbrev(std::move(Abbv));
3666 
3667   SmallVector<unsigned, 64> Vals;
3668   forEachModule(
3669       [&](const StringMapEntry<std::pair<uint64_t, ModuleHash>> &MPSE) {
3670         StringRef Key = MPSE.getKey();
3671         const auto &Value = MPSE.getValue();
3672         StringEncoding Bits = getStringEncoding(Key);
3673         unsigned AbbrevToUse = Abbrev8Bit;
3674         if (Bits == SE_Char6)
3675           AbbrevToUse = Abbrev6Bit;
3676         else if (Bits == SE_Fixed7)
3677           AbbrevToUse = Abbrev7Bit;
3678 
3679         Vals.push_back(Value.first);
3680         Vals.append(Key.begin(), Key.end());
3681 
3682         // Emit the finished record.
3683         Stream.EmitRecord(bitc::MST_CODE_ENTRY, Vals, AbbrevToUse);
3684 
3685         // Emit an optional hash for the module now
3686         const auto &Hash = Value.second;
3687         if (llvm::any_of(Hash, [](uint32_t H) { return H; })) {
3688           Vals.assign(Hash.begin(), Hash.end());
3689           // Emit the hash record.
3690           Stream.EmitRecord(bitc::MST_CODE_HASH, Vals, AbbrevHash);
3691         }
3692 
3693         Vals.clear();
3694       });
3695   Stream.ExitBlock();
3696 }
3697 
3698 /// Write the function type metadata related records that need to appear before
3699 /// a function summary entry (whether per-module or combined).
3700 template <typename Fn>
3701 static void writeFunctionTypeMetadataRecords(BitstreamWriter &Stream,
3702                                              FunctionSummary *FS,
3703                                              Fn GetValueID) {
3704   if (!FS->type_tests().empty())
3705     Stream.EmitRecord(bitc::FS_TYPE_TESTS, FS->type_tests());
3706 
3707   SmallVector<uint64_t, 64> Record;
3708 
3709   auto WriteVFuncIdVec = [&](uint64_t Ty,
3710                              ArrayRef<FunctionSummary::VFuncId> VFs) {
3711     if (VFs.empty())
3712       return;
3713     Record.clear();
3714     for (auto &VF : VFs) {
3715       Record.push_back(VF.GUID);
3716       Record.push_back(VF.Offset);
3717     }
3718     Stream.EmitRecord(Ty, Record);
3719   };
3720 
3721   WriteVFuncIdVec(bitc::FS_TYPE_TEST_ASSUME_VCALLS,
3722                   FS->type_test_assume_vcalls());
3723   WriteVFuncIdVec(bitc::FS_TYPE_CHECKED_LOAD_VCALLS,
3724                   FS->type_checked_load_vcalls());
3725 
3726   auto WriteConstVCallVec = [&](uint64_t Ty,
3727                                 ArrayRef<FunctionSummary::ConstVCall> VCs) {
3728     for (auto &VC : VCs) {
3729       Record.clear();
3730       Record.push_back(VC.VFunc.GUID);
3731       Record.push_back(VC.VFunc.Offset);
3732       llvm::append_range(Record, VC.Args);
3733       Stream.EmitRecord(Ty, Record);
3734     }
3735   };
3736 
3737   WriteConstVCallVec(bitc::FS_TYPE_TEST_ASSUME_CONST_VCALL,
3738                      FS->type_test_assume_const_vcalls());
3739   WriteConstVCallVec(bitc::FS_TYPE_CHECKED_LOAD_CONST_VCALL,
3740                      FS->type_checked_load_const_vcalls());
3741 
3742   auto WriteRange = [&](ConstantRange Range) {
3743     Range = Range.sextOrTrunc(FunctionSummary::ParamAccess::RangeWidth);
3744     assert(Range.getLower().getNumWords() == 1);
3745     assert(Range.getUpper().getNumWords() == 1);
3746     emitSignedInt64(Record, *Range.getLower().getRawData());
3747     emitSignedInt64(Record, *Range.getUpper().getRawData());
3748   };
3749 
3750   if (!FS->paramAccesses().empty()) {
3751     Record.clear();
3752     for (auto &Arg : FS->paramAccesses()) {
3753       size_t UndoSize = Record.size();
3754       Record.push_back(Arg.ParamNo);
3755       WriteRange(Arg.Use);
3756       Record.push_back(Arg.Calls.size());
3757       for (auto &Call : Arg.Calls) {
3758         Record.push_back(Call.ParamNo);
3759         Optional<unsigned> ValueID = GetValueID(Call.Callee);
3760         if (!ValueID) {
3761           // If ValueID is unknown we can't drop just this call, we must drop
3762           // entire parameter.
3763           Record.resize(UndoSize);
3764           break;
3765         }
3766         Record.push_back(*ValueID);
3767         WriteRange(Call.Offsets);
3768       }
3769     }
3770     if (!Record.empty())
3771       Stream.EmitRecord(bitc::FS_PARAM_ACCESS, Record);
3772   }
3773 }
3774 
3775 /// Collect type IDs from type tests used by function.
3776 static void
3777 getReferencedTypeIds(FunctionSummary *FS,
3778                      std::set<GlobalValue::GUID> &ReferencedTypeIds) {
3779   if (!FS->type_tests().empty())
3780     for (auto &TT : FS->type_tests())
3781       ReferencedTypeIds.insert(TT);
3782 
3783   auto GetReferencedTypesFromVFuncIdVec =
3784       [&](ArrayRef<FunctionSummary::VFuncId> VFs) {
3785         for (auto &VF : VFs)
3786           ReferencedTypeIds.insert(VF.GUID);
3787       };
3788 
3789   GetReferencedTypesFromVFuncIdVec(FS->type_test_assume_vcalls());
3790   GetReferencedTypesFromVFuncIdVec(FS->type_checked_load_vcalls());
3791 
3792   auto GetReferencedTypesFromConstVCallVec =
3793       [&](ArrayRef<FunctionSummary::ConstVCall> VCs) {
3794         for (auto &VC : VCs)
3795           ReferencedTypeIds.insert(VC.VFunc.GUID);
3796       };
3797 
3798   GetReferencedTypesFromConstVCallVec(FS->type_test_assume_const_vcalls());
3799   GetReferencedTypesFromConstVCallVec(FS->type_checked_load_const_vcalls());
3800 }
3801 
3802 static void writeWholeProgramDevirtResolutionByArg(
3803     SmallVector<uint64_t, 64> &NameVals, const std::vector<uint64_t> &args,
3804     const WholeProgramDevirtResolution::ByArg &ByArg) {
3805   NameVals.push_back(args.size());
3806   llvm::append_range(NameVals, args);
3807 
3808   NameVals.push_back(ByArg.TheKind);
3809   NameVals.push_back(ByArg.Info);
3810   NameVals.push_back(ByArg.Byte);
3811   NameVals.push_back(ByArg.Bit);
3812 }
3813 
3814 static void writeWholeProgramDevirtResolution(
3815     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3816     uint64_t Id, const WholeProgramDevirtResolution &Wpd) {
3817   NameVals.push_back(Id);
3818 
3819   NameVals.push_back(Wpd.TheKind);
3820   NameVals.push_back(StrtabBuilder.add(Wpd.SingleImplName));
3821   NameVals.push_back(Wpd.SingleImplName.size());
3822 
3823   NameVals.push_back(Wpd.ResByArg.size());
3824   for (auto &A : Wpd.ResByArg)
3825     writeWholeProgramDevirtResolutionByArg(NameVals, A.first, A.second);
3826 }
3827 
3828 static void writeTypeIdSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
3829                                      StringTableBuilder &StrtabBuilder,
3830                                      const std::string &Id,
3831                                      const TypeIdSummary &Summary) {
3832   NameVals.push_back(StrtabBuilder.add(Id));
3833   NameVals.push_back(Id.size());
3834 
3835   NameVals.push_back(Summary.TTRes.TheKind);
3836   NameVals.push_back(Summary.TTRes.SizeM1BitWidth);
3837   NameVals.push_back(Summary.TTRes.AlignLog2);
3838   NameVals.push_back(Summary.TTRes.SizeM1);
3839   NameVals.push_back(Summary.TTRes.BitMask);
3840   NameVals.push_back(Summary.TTRes.InlineBits);
3841 
3842   for (auto &W : Summary.WPDRes)
3843     writeWholeProgramDevirtResolution(NameVals, StrtabBuilder, W.first,
3844                                       W.second);
3845 }
3846 
3847 static void writeTypeIdCompatibleVtableSummaryRecord(
3848     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3849     const std::string &Id, const TypeIdCompatibleVtableInfo &Summary,
3850     ValueEnumerator &VE) {
3851   NameVals.push_back(StrtabBuilder.add(Id));
3852   NameVals.push_back(Id.size());
3853 
3854   for (auto &P : Summary) {
3855     NameVals.push_back(P.AddressPointOffset);
3856     NameVals.push_back(VE.getValueID(P.VTableVI.getValue()));
3857   }
3858 }
3859 
3860 // Helper to emit a single function summary record.
3861 void ModuleBitcodeWriterBase::writePerModuleFunctionSummaryRecord(
3862     SmallVector<uint64_t, 64> &NameVals, GlobalValueSummary *Summary,
3863     unsigned ValueID, unsigned FSCallsAbbrev, unsigned FSCallsProfileAbbrev,
3864     const Function &F) {
3865   NameVals.push_back(ValueID);
3866 
3867   FunctionSummary *FS = cast<FunctionSummary>(Summary);
3868 
3869   writeFunctionTypeMetadataRecords(
3870       Stream, FS, [&](const ValueInfo &VI) -> Optional<unsigned> {
3871         return {VE.getValueID(VI.getValue())};
3872       });
3873 
3874   auto SpecialRefCnts = FS->specialRefCounts();
3875   NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
3876   NameVals.push_back(FS->instCount());
3877   NameVals.push_back(getEncodedFFlags(FS->fflags()));
3878   NameVals.push_back(FS->refs().size());
3879   NameVals.push_back(SpecialRefCnts.first);  // rorefcnt
3880   NameVals.push_back(SpecialRefCnts.second); // worefcnt
3881 
3882   for (auto &RI : FS->refs())
3883     NameVals.push_back(VE.getValueID(RI.getValue()));
3884 
3885   bool HasProfileData =
3886       F.hasProfileData() || ForceSummaryEdgesCold != FunctionSummary::FSHT_None;
3887   for (auto &ECI : FS->calls()) {
3888     NameVals.push_back(getValueId(ECI.first));
3889     if (HasProfileData)
3890       NameVals.push_back(static_cast<uint8_t>(ECI.second.Hotness));
3891     else if (WriteRelBFToSummary)
3892       NameVals.push_back(ECI.second.RelBlockFreq);
3893   }
3894 
3895   unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
3896   unsigned Code =
3897       (HasProfileData ? bitc::FS_PERMODULE_PROFILE
3898                       : (WriteRelBFToSummary ? bitc::FS_PERMODULE_RELBF
3899                                              : bitc::FS_PERMODULE));
3900 
3901   // Emit the finished record.
3902   Stream.EmitRecord(Code, NameVals, FSAbbrev);
3903   NameVals.clear();
3904 }
3905 
3906 // Collect the global value references in the given variable's initializer,
3907 // and emit them in a summary record.
3908 void ModuleBitcodeWriterBase::writeModuleLevelReferences(
3909     const GlobalVariable &V, SmallVector<uint64_t, 64> &NameVals,
3910     unsigned FSModRefsAbbrev, unsigned FSModVTableRefsAbbrev) {
3911   auto VI = Index->getValueInfo(V.getGUID());
3912   if (!VI || VI.getSummaryList().empty()) {
3913     // Only declarations should not have a summary (a declaration might however
3914     // have a summary if the def was in module level asm).
3915     assert(V.isDeclaration());
3916     return;
3917   }
3918   auto *Summary = VI.getSummaryList()[0].get();
3919   NameVals.push_back(VE.getValueID(&V));
3920   GlobalVarSummary *VS = cast<GlobalVarSummary>(Summary);
3921   NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
3922   NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
3923 
3924   auto VTableFuncs = VS->vTableFuncs();
3925   if (!VTableFuncs.empty())
3926     NameVals.push_back(VS->refs().size());
3927 
3928   unsigned SizeBeforeRefs = NameVals.size();
3929   for (auto &RI : VS->refs())
3930     NameVals.push_back(VE.getValueID(RI.getValue()));
3931   // Sort the refs for determinism output, the vector returned by FS->refs() has
3932   // been initialized from a DenseSet.
3933   llvm::sort(drop_begin(NameVals, SizeBeforeRefs));
3934 
3935   if (VTableFuncs.empty())
3936     Stream.EmitRecord(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS, NameVals,
3937                       FSModRefsAbbrev);
3938   else {
3939     // VTableFuncs pairs should already be sorted by offset.
3940     for (auto &P : VTableFuncs) {
3941       NameVals.push_back(VE.getValueID(P.FuncVI.getValue()));
3942       NameVals.push_back(P.VTableOffset);
3943     }
3944 
3945     Stream.EmitRecord(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS, NameVals,
3946                       FSModVTableRefsAbbrev);
3947   }
3948   NameVals.clear();
3949 }
3950 
3951 /// Emit the per-module summary section alongside the rest of
3952 /// the module's bitcode.
3953 void ModuleBitcodeWriterBase::writePerModuleGlobalValueSummary() {
3954   // By default we compile with ThinLTO if the module has a summary, but the
3955   // client can request full LTO with a module flag.
3956   bool IsThinLTO = true;
3957   if (auto *MD =
3958           mdconst::extract_or_null<ConstantInt>(M.getModuleFlag("ThinLTO")))
3959     IsThinLTO = MD->getZExtValue();
3960   Stream.EnterSubblock(IsThinLTO ? bitc::GLOBALVAL_SUMMARY_BLOCK_ID
3961                                  : bitc::FULL_LTO_GLOBALVAL_SUMMARY_BLOCK_ID,
3962                        4);
3963 
3964   Stream.EmitRecord(
3965       bitc::FS_VERSION,
3966       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
3967 
3968   // Write the index flags.
3969   uint64_t Flags = 0;
3970   // Bits 1-3 are set only in the combined index, skip them.
3971   if (Index->enableSplitLTOUnit())
3972     Flags |= 0x8;
3973   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Flags});
3974 
3975   if (Index->begin() == Index->end()) {
3976     Stream.ExitBlock();
3977     return;
3978   }
3979 
3980   for (const auto &GVI : valueIds()) {
3981     Stream.EmitRecord(bitc::FS_VALUE_GUID,
3982                       ArrayRef<uint64_t>{GVI.second, GVI.first});
3983   }
3984 
3985   // Abbrev for FS_PERMODULE_PROFILE.
3986   auto Abbv = std::make_shared<BitCodeAbbrev>();
3987   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_PROFILE));
3988   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3989   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3990   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3991   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3992   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3993   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
3994   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
3995   // numrefs x valueid, n x (valueid, hotness)
3996   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3997   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3998   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3999 
4000   // Abbrev for FS_PERMODULE or FS_PERMODULE_RELBF.
4001   Abbv = std::make_shared<BitCodeAbbrev>();
4002   if (WriteRelBFToSummary)
4003     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_RELBF));
4004   else
4005     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE));
4006   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4007   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4008   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4009   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4010   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4011   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4012   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4013   // numrefs x valueid, n x (valueid [, rel_block_freq])
4014   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4015   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4016   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4017 
4018   // Abbrev for FS_PERMODULE_GLOBALVAR_INIT_REFS.
4019   Abbv = std::make_shared<BitCodeAbbrev>();
4020   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS));
4021   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
4022   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
4023   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));  // valueids
4024   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4025   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4026 
4027   // Abbrev for FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS.
4028   Abbv = std::make_shared<BitCodeAbbrev>();
4029   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS));
4030   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
4031   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
4032   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numrefs
4033   // numrefs x valueid, n x (valueid , offset)
4034   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4035   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4036   unsigned FSModVTableRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4037 
4038   // Abbrev for FS_ALIAS.
4039   Abbv = std::make_shared<BitCodeAbbrev>();
4040   Abbv->Add(BitCodeAbbrevOp(bitc::FS_ALIAS));
4041   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4042   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4043   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4044   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4045 
4046   // Abbrev for FS_TYPE_ID_METADATA
4047   Abbv = std::make_shared<BitCodeAbbrev>();
4048   Abbv->Add(BitCodeAbbrevOp(bitc::FS_TYPE_ID_METADATA));
4049   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid strtab index
4050   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid length
4051   // n x (valueid , offset)
4052   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4053   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4054   unsigned TypeIdCompatibleVtableAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4055 
4056   SmallVector<uint64_t, 64> NameVals;
4057   // Iterate over the list of functions instead of the Index to
4058   // ensure the ordering is stable.
4059   for (const Function &F : M) {
4060     // Summary emission does not support anonymous functions, they have to
4061     // renamed using the anonymous function renaming pass.
4062     if (!F.hasName())
4063       report_fatal_error("Unexpected anonymous function when writing summary");
4064 
4065     ValueInfo VI = Index->getValueInfo(F.getGUID());
4066     if (!VI || VI.getSummaryList().empty()) {
4067       // Only declarations should not have a summary (a declaration might
4068       // however have a summary if the def was in module level asm).
4069       assert(F.isDeclaration());
4070       continue;
4071     }
4072     auto *Summary = VI.getSummaryList()[0].get();
4073     writePerModuleFunctionSummaryRecord(NameVals, Summary, VE.getValueID(&F),
4074                                         FSCallsAbbrev, FSCallsProfileAbbrev, F);
4075   }
4076 
4077   // Capture references from GlobalVariable initializers, which are outside
4078   // of a function scope.
4079   for (const GlobalVariable &G : M.globals())
4080     writeModuleLevelReferences(G, NameVals, FSModRefsAbbrev,
4081                                FSModVTableRefsAbbrev);
4082 
4083   for (const GlobalAlias &A : M.aliases()) {
4084     auto *Aliasee = A.getAliaseeObject();
4085     if (!Aliasee->hasName())
4086       // Nameless function don't have an entry in the summary, skip it.
4087       continue;
4088     auto AliasId = VE.getValueID(&A);
4089     auto AliaseeId = VE.getValueID(Aliasee);
4090     NameVals.push_back(AliasId);
4091     auto *Summary = Index->getGlobalValueSummary(A);
4092     AliasSummary *AS = cast<AliasSummary>(Summary);
4093     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
4094     NameVals.push_back(AliaseeId);
4095     Stream.EmitRecord(bitc::FS_ALIAS, NameVals, FSAliasAbbrev);
4096     NameVals.clear();
4097   }
4098 
4099   for (auto &S : Index->typeIdCompatibleVtableMap()) {
4100     writeTypeIdCompatibleVtableSummaryRecord(NameVals, StrtabBuilder, S.first,
4101                                              S.second, VE);
4102     Stream.EmitRecord(bitc::FS_TYPE_ID_METADATA, NameVals,
4103                       TypeIdCompatibleVtableAbbrev);
4104     NameVals.clear();
4105   }
4106 
4107   Stream.EmitRecord(bitc::FS_BLOCK_COUNT,
4108                     ArrayRef<uint64_t>{Index->getBlockCount()});
4109 
4110   Stream.ExitBlock();
4111 }
4112 
4113 /// Emit the combined summary section into the combined index file.
4114 void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
4115   Stream.EnterSubblock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID, 3);
4116   Stream.EmitRecord(
4117       bitc::FS_VERSION,
4118       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
4119 
4120   // Write the index flags.
4121   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Index.getFlags()});
4122 
4123   for (const auto &GVI : valueIds()) {
4124     Stream.EmitRecord(bitc::FS_VALUE_GUID,
4125                       ArrayRef<uint64_t>{GVI.second, GVI.first});
4126   }
4127 
4128   // Abbrev for FS_COMBINED.
4129   auto Abbv = std::make_shared<BitCodeAbbrev>();
4130   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED));
4131   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4132   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4133   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4134   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4135   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4136   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
4137   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4138   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4139   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4140   // numrefs x valueid, n x (valueid)
4141   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4142   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4143   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4144 
4145   // Abbrev for FS_COMBINED_PROFILE.
4146   Abbv = std::make_shared<BitCodeAbbrev>();
4147   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_PROFILE));
4148   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4149   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4150   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4151   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4152   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4153   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
4154   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4155   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4156   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4157   // numrefs x valueid, n x (valueid, hotness)
4158   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4159   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4160   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4161 
4162   // Abbrev for FS_COMBINED_GLOBALVAR_INIT_REFS.
4163   Abbv = std::make_shared<BitCodeAbbrev>();
4164   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS));
4165   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4166   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4167   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4168   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));    // valueids
4169   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4170   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4171 
4172   // Abbrev for FS_COMBINED_ALIAS.
4173   Abbv = std::make_shared<BitCodeAbbrev>();
4174   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_ALIAS));
4175   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4176   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4177   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4178   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4179   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4180 
4181   // The aliases are emitted as a post-pass, and will point to the value
4182   // id of the aliasee. Save them in a vector for post-processing.
4183   SmallVector<AliasSummary *, 64> Aliases;
4184 
4185   // Save the value id for each summary for alias emission.
4186   DenseMap<const GlobalValueSummary *, unsigned> SummaryToValueIdMap;
4187 
4188   SmallVector<uint64_t, 64> NameVals;
4189 
4190   // Set that will be populated during call to writeFunctionTypeMetadataRecords
4191   // with the type ids referenced by this index file.
4192   std::set<GlobalValue::GUID> ReferencedTypeIds;
4193 
4194   // For local linkage, we also emit the original name separately
4195   // immediately after the record.
4196   auto MaybeEmitOriginalName = [&](GlobalValueSummary &S) {
4197     // We don't need to emit the original name if we are writing the index for
4198     // distributed backends (in which case ModuleToSummariesForIndex is
4199     // non-null). The original name is only needed during the thin link, since
4200     // for SamplePGO the indirect call targets for local functions have
4201     // have the original name annotated in profile.
4202     // Continue to emit it when writing out the entire combined index, which is
4203     // used in testing the thin link via llvm-lto.
4204     if (ModuleToSummariesForIndex || !GlobalValue::isLocalLinkage(S.linkage()))
4205       return;
4206     NameVals.push_back(S.getOriginalName());
4207     Stream.EmitRecord(bitc::FS_COMBINED_ORIGINAL_NAME, NameVals);
4208     NameVals.clear();
4209   };
4210 
4211   std::set<GlobalValue::GUID> DefOrUseGUIDs;
4212   forEachSummary([&](GVInfo I, bool IsAliasee) {
4213     GlobalValueSummary *S = I.second;
4214     assert(S);
4215     DefOrUseGUIDs.insert(I.first);
4216     for (const ValueInfo &VI : S->refs())
4217       DefOrUseGUIDs.insert(VI.getGUID());
4218 
4219     auto ValueId = getValueId(I.first);
4220     assert(ValueId);
4221     SummaryToValueIdMap[S] = *ValueId;
4222 
4223     // If this is invoked for an aliasee, we want to record the above
4224     // mapping, but then not emit a summary entry (if the aliasee is
4225     // to be imported, we will invoke this separately with IsAliasee=false).
4226     if (IsAliasee)
4227       return;
4228 
4229     if (auto *AS = dyn_cast<AliasSummary>(S)) {
4230       // Will process aliases as a post-pass because the reader wants all
4231       // global to be loaded first.
4232       Aliases.push_back(AS);
4233       return;
4234     }
4235 
4236     if (auto *VS = dyn_cast<GlobalVarSummary>(S)) {
4237       NameVals.push_back(*ValueId);
4238       NameVals.push_back(Index.getModuleId(VS->modulePath()));
4239       NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
4240       NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
4241       for (auto &RI : VS->refs()) {
4242         auto RefValueId = getValueId(RI.getGUID());
4243         if (!RefValueId)
4244           continue;
4245         NameVals.push_back(*RefValueId);
4246       }
4247 
4248       // Emit the finished record.
4249       Stream.EmitRecord(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS, NameVals,
4250                         FSModRefsAbbrev);
4251       NameVals.clear();
4252       MaybeEmitOriginalName(*S);
4253       return;
4254     }
4255 
4256     auto GetValueId = [&](const ValueInfo &VI) -> Optional<unsigned> {
4257       return getValueId(VI.getGUID());
4258     };
4259 
4260     auto *FS = cast<FunctionSummary>(S);
4261     writeFunctionTypeMetadataRecords(Stream, FS, GetValueId);
4262     getReferencedTypeIds(FS, ReferencedTypeIds);
4263 
4264     NameVals.push_back(*ValueId);
4265     NameVals.push_back(Index.getModuleId(FS->modulePath()));
4266     NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
4267     NameVals.push_back(FS->instCount());
4268     NameVals.push_back(getEncodedFFlags(FS->fflags()));
4269     NameVals.push_back(FS->entryCount());
4270 
4271     // Fill in below
4272     NameVals.push_back(0); // numrefs
4273     NameVals.push_back(0); // rorefcnt
4274     NameVals.push_back(0); // worefcnt
4275 
4276     unsigned Count = 0, RORefCnt = 0, WORefCnt = 0;
4277     for (auto &RI : FS->refs()) {
4278       auto RefValueId = getValueId(RI.getGUID());
4279       if (!RefValueId)
4280         continue;
4281       NameVals.push_back(*RefValueId);
4282       if (RI.isReadOnly())
4283         RORefCnt++;
4284       else if (RI.isWriteOnly())
4285         WORefCnt++;
4286       Count++;
4287     }
4288     NameVals[6] = Count;
4289     NameVals[7] = RORefCnt;
4290     NameVals[8] = WORefCnt;
4291 
4292     bool HasProfileData = false;
4293     for (auto &EI : FS->calls()) {
4294       HasProfileData |=
4295           EI.second.getHotness() != CalleeInfo::HotnessType::Unknown;
4296       if (HasProfileData)
4297         break;
4298     }
4299 
4300     for (auto &EI : FS->calls()) {
4301       // If this GUID doesn't have a value id, it doesn't have a function
4302       // summary and we don't need to record any calls to it.
4303       Optional<unsigned> CallValueId = GetValueId(EI.first);
4304       if (!CallValueId)
4305         continue;
4306       NameVals.push_back(*CallValueId);
4307       if (HasProfileData)
4308         NameVals.push_back(static_cast<uint8_t>(EI.second.Hotness));
4309     }
4310 
4311     unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
4312     unsigned Code =
4313         (HasProfileData ? bitc::FS_COMBINED_PROFILE : bitc::FS_COMBINED);
4314 
4315     // Emit the finished record.
4316     Stream.EmitRecord(Code, NameVals, FSAbbrev);
4317     NameVals.clear();
4318     MaybeEmitOriginalName(*S);
4319   });
4320 
4321   for (auto *AS : Aliases) {
4322     auto AliasValueId = SummaryToValueIdMap[AS];
4323     assert(AliasValueId);
4324     NameVals.push_back(AliasValueId);
4325     NameVals.push_back(Index.getModuleId(AS->modulePath()));
4326     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
4327     auto AliaseeValueId = SummaryToValueIdMap[&AS->getAliasee()];
4328     assert(AliaseeValueId);
4329     NameVals.push_back(AliaseeValueId);
4330 
4331     // Emit the finished record.
4332     Stream.EmitRecord(bitc::FS_COMBINED_ALIAS, NameVals, FSAliasAbbrev);
4333     NameVals.clear();
4334     MaybeEmitOriginalName(*AS);
4335 
4336     if (auto *FS = dyn_cast<FunctionSummary>(&AS->getAliasee()))
4337       getReferencedTypeIds(FS, ReferencedTypeIds);
4338   }
4339 
4340   if (!Index.cfiFunctionDefs().empty()) {
4341     for (auto &S : Index.cfiFunctionDefs()) {
4342       if (DefOrUseGUIDs.count(
4343               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4344         NameVals.push_back(StrtabBuilder.add(S));
4345         NameVals.push_back(S.size());
4346       }
4347     }
4348     if (!NameVals.empty()) {
4349       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DEFS, NameVals);
4350       NameVals.clear();
4351     }
4352   }
4353 
4354   if (!Index.cfiFunctionDecls().empty()) {
4355     for (auto &S : Index.cfiFunctionDecls()) {
4356       if (DefOrUseGUIDs.count(
4357               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4358         NameVals.push_back(StrtabBuilder.add(S));
4359         NameVals.push_back(S.size());
4360       }
4361     }
4362     if (!NameVals.empty()) {
4363       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DECLS, NameVals);
4364       NameVals.clear();
4365     }
4366   }
4367 
4368   // Walk the GUIDs that were referenced, and write the
4369   // corresponding type id records.
4370   for (auto &T : ReferencedTypeIds) {
4371     auto TidIter = Index.typeIds().equal_range(T);
4372     for (auto It = TidIter.first; It != TidIter.second; ++It) {
4373       writeTypeIdSummaryRecord(NameVals, StrtabBuilder, It->second.first,
4374                                It->second.second);
4375       Stream.EmitRecord(bitc::FS_TYPE_ID, NameVals);
4376       NameVals.clear();
4377     }
4378   }
4379 
4380   Stream.EmitRecord(bitc::FS_BLOCK_COUNT,
4381                     ArrayRef<uint64_t>{Index.getBlockCount()});
4382 
4383   Stream.ExitBlock();
4384 }
4385 
4386 /// Create the "IDENTIFICATION_BLOCK_ID" containing a single string with the
4387 /// current llvm version, and a record for the epoch number.
4388 static void writeIdentificationBlock(BitstreamWriter &Stream) {
4389   Stream.EnterSubblock(bitc::IDENTIFICATION_BLOCK_ID, 5);
4390 
4391   // Write the "user readable" string identifying the bitcode producer
4392   auto Abbv = std::make_shared<BitCodeAbbrev>();
4393   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_STRING));
4394   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4395   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
4396   auto StringAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4397   writeStringRecord(Stream, bitc::IDENTIFICATION_CODE_STRING,
4398                     "LLVM" LLVM_VERSION_STRING, StringAbbrev);
4399 
4400   // Write the epoch version
4401   Abbv = std::make_shared<BitCodeAbbrev>();
4402   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_EPOCH));
4403   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
4404   auto EpochAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4405   constexpr std::array<unsigned, 1> Vals = {{bitc::BITCODE_CURRENT_EPOCH}};
4406   Stream.EmitRecord(bitc::IDENTIFICATION_CODE_EPOCH, Vals, EpochAbbrev);
4407   Stream.ExitBlock();
4408 }
4409 
4410 void ModuleBitcodeWriter::writeModuleHash(size_t BlockStartPos) {
4411   // Emit the module's hash.
4412   // MODULE_CODE_HASH: [5*i32]
4413   if (GenerateHash) {
4414     uint32_t Vals[5];
4415     Hasher.update(ArrayRef<uint8_t>((const uint8_t *)&(Buffer)[BlockStartPos],
4416                                     Buffer.size() - BlockStartPos));
4417     std::array<uint8_t, 20> Hash = Hasher.result();
4418     for (int Pos = 0; Pos < 20; Pos += 4) {
4419       Vals[Pos / 4] = support::endian::read32be(Hash.data() + Pos);
4420     }
4421 
4422     // Emit the finished record.
4423     Stream.EmitRecord(bitc::MODULE_CODE_HASH, Vals);
4424 
4425     if (ModHash)
4426       // Save the written hash value.
4427       llvm::copy(Vals, std::begin(*ModHash));
4428   }
4429 }
4430 
4431 void ModuleBitcodeWriter::write() {
4432   writeIdentificationBlock(Stream);
4433 
4434   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4435   size_t BlockStartPos = Buffer.size();
4436 
4437   writeModuleVersion();
4438 
4439   // Emit blockinfo, which defines the standard abbreviations etc.
4440   writeBlockInfo();
4441 
4442   // Emit information describing all of the types in the module.
4443   writeTypeTable();
4444 
4445   // Emit information about attribute groups.
4446   writeAttributeGroupTable();
4447 
4448   // Emit information about parameter attributes.
4449   writeAttributeTable();
4450 
4451   writeComdats();
4452 
4453   // Emit top-level description of module, including target triple, inline asm,
4454   // descriptors for global variables, and function prototype info.
4455   writeModuleInfo();
4456 
4457   // Emit constants.
4458   writeModuleConstants();
4459 
4460   // Emit metadata kind names.
4461   writeModuleMetadataKinds();
4462 
4463   // Emit metadata.
4464   writeModuleMetadata();
4465 
4466   // Emit module-level use-lists.
4467   if (VE.shouldPreserveUseListOrder())
4468     writeUseListBlock(nullptr);
4469 
4470   writeOperandBundleTags();
4471   writeSyncScopeNames();
4472 
4473   // Emit function bodies.
4474   DenseMap<const Function *, uint64_t> FunctionToBitcodeIndex;
4475   for (const Function &F : M)
4476     if (!F.isDeclaration())
4477       writeFunction(F, FunctionToBitcodeIndex);
4478 
4479   // Need to write after the above call to WriteFunction which populates
4480   // the summary information in the index.
4481   if (Index)
4482     writePerModuleGlobalValueSummary();
4483 
4484   writeGlobalValueSymbolTable(FunctionToBitcodeIndex);
4485 
4486   writeModuleHash(BlockStartPos);
4487 
4488   Stream.ExitBlock();
4489 }
4490 
4491 static void writeInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
4492                                uint32_t &Position) {
4493   support::endian::write32le(&Buffer[Position], Value);
4494   Position += 4;
4495 }
4496 
4497 /// If generating a bc file on darwin, we have to emit a
4498 /// header and trailer to make it compatible with the system archiver.  To do
4499 /// this we emit the following header, and then emit a trailer that pads the
4500 /// file out to be a multiple of 16 bytes.
4501 ///
4502 /// struct bc_header {
4503 ///   uint32_t Magic;         // 0x0B17C0DE
4504 ///   uint32_t Version;       // Version, currently always 0.
4505 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
4506 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
4507 ///   uint32_t CPUType;       // CPU specifier.
4508 ///   ... potentially more later ...
4509 /// };
4510 static void emitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
4511                                          const Triple &TT) {
4512   unsigned CPUType = ~0U;
4513 
4514   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
4515   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
4516   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
4517   // specific constants here because they are implicitly part of the Darwin ABI.
4518   enum {
4519     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
4520     DARWIN_CPU_TYPE_X86        = 7,
4521     DARWIN_CPU_TYPE_ARM        = 12,
4522     DARWIN_CPU_TYPE_POWERPC    = 18
4523   };
4524 
4525   Triple::ArchType Arch = TT.getArch();
4526   if (Arch == Triple::x86_64)
4527     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
4528   else if (Arch == Triple::x86)
4529     CPUType = DARWIN_CPU_TYPE_X86;
4530   else if (Arch == Triple::ppc)
4531     CPUType = DARWIN_CPU_TYPE_POWERPC;
4532   else if (Arch == Triple::ppc64)
4533     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
4534   else if (Arch == Triple::arm || Arch == Triple::thumb)
4535     CPUType = DARWIN_CPU_TYPE_ARM;
4536 
4537   // Traditional Bitcode starts after header.
4538   assert(Buffer.size() >= BWH_HeaderSize &&
4539          "Expected header size to be reserved");
4540   unsigned BCOffset = BWH_HeaderSize;
4541   unsigned BCSize = Buffer.size() - BWH_HeaderSize;
4542 
4543   // Write the magic and version.
4544   unsigned Position = 0;
4545   writeInt32ToBuffer(0x0B17C0DE, Buffer, Position);
4546   writeInt32ToBuffer(0, Buffer, Position); // Version.
4547   writeInt32ToBuffer(BCOffset, Buffer, Position);
4548   writeInt32ToBuffer(BCSize, Buffer, Position);
4549   writeInt32ToBuffer(CPUType, Buffer, Position);
4550 
4551   // If the file is not a multiple of 16 bytes, insert dummy padding.
4552   while (Buffer.size() & 15)
4553     Buffer.push_back(0);
4554 }
4555 
4556 /// Helper to write the header common to all bitcode files.
4557 static void writeBitcodeHeader(BitstreamWriter &Stream) {
4558   // Emit the file header.
4559   Stream.Emit((unsigned)'B', 8);
4560   Stream.Emit((unsigned)'C', 8);
4561   Stream.Emit(0x0, 4);
4562   Stream.Emit(0xC, 4);
4563   Stream.Emit(0xE, 4);
4564   Stream.Emit(0xD, 4);
4565 }
4566 
4567 BitcodeWriter::BitcodeWriter(SmallVectorImpl<char> &Buffer, raw_fd_stream *FS)
4568     : Buffer(Buffer), Stream(new BitstreamWriter(Buffer, FS, FlushThreshold)) {
4569   writeBitcodeHeader(*Stream);
4570 }
4571 
4572 BitcodeWriter::~BitcodeWriter() { assert(WroteStrtab); }
4573 
4574 void BitcodeWriter::writeBlob(unsigned Block, unsigned Record, StringRef Blob) {
4575   Stream->EnterSubblock(Block, 3);
4576 
4577   auto Abbv = std::make_shared<BitCodeAbbrev>();
4578   Abbv->Add(BitCodeAbbrevOp(Record));
4579   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
4580   auto AbbrevNo = Stream->EmitAbbrev(std::move(Abbv));
4581 
4582   Stream->EmitRecordWithBlob(AbbrevNo, ArrayRef<uint64_t>{Record}, Blob);
4583 
4584   Stream->ExitBlock();
4585 }
4586 
4587 void BitcodeWriter::writeSymtab() {
4588   assert(!WroteStrtab && !WroteSymtab);
4589 
4590   // If any module has module-level inline asm, we will require a registered asm
4591   // parser for the target so that we can create an accurate symbol table for
4592   // the module.
4593   for (Module *M : Mods) {
4594     if (M->getModuleInlineAsm().empty())
4595       continue;
4596 
4597     std::string Err;
4598     const Triple TT(M->getTargetTriple());
4599     const Target *T = TargetRegistry::lookupTarget(TT.str(), Err);
4600     if (!T || !T->hasMCAsmParser())
4601       return;
4602   }
4603 
4604   WroteSymtab = true;
4605   SmallVector<char, 0> Symtab;
4606   // The irsymtab::build function may be unable to create a symbol table if the
4607   // module is malformed (e.g. it contains an invalid alias). Writing a symbol
4608   // table is not required for correctness, but we still want to be able to
4609   // write malformed modules to bitcode files, so swallow the error.
4610   if (Error E = irsymtab::build(Mods, Symtab, StrtabBuilder, Alloc)) {
4611     consumeError(std::move(E));
4612     return;
4613   }
4614 
4615   writeBlob(bitc::SYMTAB_BLOCK_ID, bitc::SYMTAB_BLOB,
4616             {Symtab.data(), Symtab.size()});
4617 }
4618 
4619 void BitcodeWriter::writeStrtab() {
4620   assert(!WroteStrtab);
4621 
4622   std::vector<char> Strtab;
4623   StrtabBuilder.finalizeInOrder();
4624   Strtab.resize(StrtabBuilder.getSize());
4625   StrtabBuilder.write((uint8_t *)Strtab.data());
4626 
4627   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB,
4628             {Strtab.data(), Strtab.size()});
4629 
4630   WroteStrtab = true;
4631 }
4632 
4633 void BitcodeWriter::copyStrtab(StringRef Strtab) {
4634   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB, Strtab);
4635   WroteStrtab = true;
4636 }
4637 
4638 void BitcodeWriter::writeModule(const Module &M,
4639                                 bool ShouldPreserveUseListOrder,
4640                                 const ModuleSummaryIndex *Index,
4641                                 bool GenerateHash, ModuleHash *ModHash) {
4642   assert(!WroteStrtab);
4643 
4644   // The Mods vector is used by irsymtab::build, which requires non-const
4645   // Modules in case it needs to materialize metadata. But the bitcode writer
4646   // requires that the module is materialized, so we can cast to non-const here,
4647   // after checking that it is in fact materialized.
4648   assert(M.isMaterialized());
4649   Mods.push_back(const_cast<Module *>(&M));
4650 
4651   ModuleBitcodeWriter ModuleWriter(M, Buffer, StrtabBuilder, *Stream,
4652                                    ShouldPreserveUseListOrder, Index,
4653                                    GenerateHash, ModHash);
4654   ModuleWriter.write();
4655 }
4656 
4657 void BitcodeWriter::writeIndex(
4658     const ModuleSummaryIndex *Index,
4659     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4660   IndexBitcodeWriter IndexWriter(*Stream, StrtabBuilder, *Index,
4661                                  ModuleToSummariesForIndex);
4662   IndexWriter.write();
4663 }
4664 
4665 /// Write the specified module to the specified output stream.
4666 void llvm::WriteBitcodeToFile(const Module &M, raw_ostream &Out,
4667                               bool ShouldPreserveUseListOrder,
4668                               const ModuleSummaryIndex *Index,
4669                               bool GenerateHash, ModuleHash *ModHash) {
4670   SmallVector<char, 0> Buffer;
4671   Buffer.reserve(256*1024);
4672 
4673   // If this is darwin or another generic macho target, reserve space for the
4674   // header.
4675   Triple TT(M.getTargetTriple());
4676   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4677     Buffer.insert(Buffer.begin(), BWH_HeaderSize, 0);
4678 
4679   BitcodeWriter Writer(Buffer, dyn_cast<raw_fd_stream>(&Out));
4680   Writer.writeModule(M, ShouldPreserveUseListOrder, Index, GenerateHash,
4681                      ModHash);
4682   Writer.writeSymtab();
4683   Writer.writeStrtab();
4684 
4685   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4686     emitDarwinBCHeaderAndTrailer(Buffer, TT);
4687 
4688   // Write the generated bitstream to "Out".
4689   if (!Buffer.empty())
4690     Out.write((char *)&Buffer.front(), Buffer.size());
4691 }
4692 
4693 void IndexBitcodeWriter::write() {
4694   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4695 
4696   writeModuleVersion();
4697 
4698   // Write the module paths in the combined index.
4699   writeModStrings();
4700 
4701   // Write the summary combined index records.
4702   writeCombinedGlobalValueSummary();
4703 
4704   Stream.ExitBlock();
4705 }
4706 
4707 // Write the specified module summary index to the given raw output stream,
4708 // where it will be written in a new bitcode block. This is used when
4709 // writing the combined index file for ThinLTO. When writing a subset of the
4710 // index for a distributed backend, provide a \p ModuleToSummariesForIndex map.
4711 void llvm::writeIndexToFile(
4712     const ModuleSummaryIndex &Index, raw_ostream &Out,
4713     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4714   SmallVector<char, 0> Buffer;
4715   Buffer.reserve(256 * 1024);
4716 
4717   BitcodeWriter Writer(Buffer);
4718   Writer.writeIndex(&Index, ModuleToSummariesForIndex);
4719   Writer.writeStrtab();
4720 
4721   Out.write((char *)&Buffer.front(), Buffer.size());
4722 }
4723 
4724 namespace {
4725 
4726 /// Class to manage the bitcode writing for a thin link bitcode file.
4727 class ThinLinkBitcodeWriter : public ModuleBitcodeWriterBase {
4728   /// ModHash is for use in ThinLTO incremental build, generated while writing
4729   /// the module bitcode file.
4730   const ModuleHash *ModHash;
4731 
4732 public:
4733   ThinLinkBitcodeWriter(const Module &M, StringTableBuilder &StrtabBuilder,
4734                         BitstreamWriter &Stream,
4735                         const ModuleSummaryIndex &Index,
4736                         const ModuleHash &ModHash)
4737       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
4738                                 /*ShouldPreserveUseListOrder=*/false, &Index),
4739         ModHash(&ModHash) {}
4740 
4741   void write();
4742 
4743 private:
4744   void writeSimplifiedModuleInfo();
4745 };
4746 
4747 } // end anonymous namespace
4748 
4749 // This function writes a simpilified module info for thin link bitcode file.
4750 // It only contains the source file name along with the name(the offset and
4751 // size in strtab) and linkage for global values. For the global value info
4752 // entry, in order to keep linkage at offset 5, there are three zeros used
4753 // as padding.
4754 void ThinLinkBitcodeWriter::writeSimplifiedModuleInfo() {
4755   SmallVector<unsigned, 64> Vals;
4756   // Emit the module's source file name.
4757   {
4758     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
4759     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
4760     if (Bits == SE_Char6)
4761       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
4762     else if (Bits == SE_Fixed7)
4763       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
4764 
4765     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
4766     auto Abbv = std::make_shared<BitCodeAbbrev>();
4767     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
4768     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4769     Abbv->Add(AbbrevOpToUse);
4770     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4771 
4772     for (const auto P : M.getSourceFileName())
4773       Vals.push_back((unsigned char)P);
4774 
4775     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
4776     Vals.clear();
4777   }
4778 
4779   // Emit the global variable information.
4780   for (const GlobalVariable &GV : M.globals()) {
4781     // GLOBALVAR: [strtab offset, strtab size, 0, 0, 0, linkage]
4782     Vals.push_back(StrtabBuilder.add(GV.getName()));
4783     Vals.push_back(GV.getName().size());
4784     Vals.push_back(0);
4785     Vals.push_back(0);
4786     Vals.push_back(0);
4787     Vals.push_back(getEncodedLinkage(GV));
4788 
4789     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals);
4790     Vals.clear();
4791   }
4792 
4793   // Emit the function proto information.
4794   for (const Function &F : M) {
4795     // FUNCTION:  [strtab offset, strtab size, 0, 0, 0, linkage]
4796     Vals.push_back(StrtabBuilder.add(F.getName()));
4797     Vals.push_back(F.getName().size());
4798     Vals.push_back(0);
4799     Vals.push_back(0);
4800     Vals.push_back(0);
4801     Vals.push_back(getEncodedLinkage(F));
4802 
4803     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals);
4804     Vals.clear();
4805   }
4806 
4807   // Emit the alias information.
4808   for (const GlobalAlias &A : M.aliases()) {
4809     // ALIAS: [strtab offset, strtab size, 0, 0, 0, linkage]
4810     Vals.push_back(StrtabBuilder.add(A.getName()));
4811     Vals.push_back(A.getName().size());
4812     Vals.push_back(0);
4813     Vals.push_back(0);
4814     Vals.push_back(0);
4815     Vals.push_back(getEncodedLinkage(A));
4816 
4817     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals);
4818     Vals.clear();
4819   }
4820 
4821   // Emit the ifunc information.
4822   for (const GlobalIFunc &I : M.ifuncs()) {
4823     // IFUNC: [strtab offset, strtab size, 0, 0, 0, linkage]
4824     Vals.push_back(StrtabBuilder.add(I.getName()));
4825     Vals.push_back(I.getName().size());
4826     Vals.push_back(0);
4827     Vals.push_back(0);
4828     Vals.push_back(0);
4829     Vals.push_back(getEncodedLinkage(I));
4830 
4831     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
4832     Vals.clear();
4833   }
4834 }
4835 
4836 void ThinLinkBitcodeWriter::write() {
4837   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4838 
4839   writeModuleVersion();
4840 
4841   writeSimplifiedModuleInfo();
4842 
4843   writePerModuleGlobalValueSummary();
4844 
4845   // Write module hash.
4846   Stream.EmitRecord(bitc::MODULE_CODE_HASH, ArrayRef<uint32_t>(*ModHash));
4847 
4848   Stream.ExitBlock();
4849 }
4850 
4851 void BitcodeWriter::writeThinLinkBitcode(const Module &M,
4852                                          const ModuleSummaryIndex &Index,
4853                                          const ModuleHash &ModHash) {
4854   assert(!WroteStrtab);
4855 
4856   // The Mods vector is used by irsymtab::build, which requires non-const
4857   // Modules in case it needs to materialize metadata. But the bitcode writer
4858   // requires that the module is materialized, so we can cast to non-const here,
4859   // after checking that it is in fact materialized.
4860   assert(M.isMaterialized());
4861   Mods.push_back(const_cast<Module *>(&M));
4862 
4863   ThinLinkBitcodeWriter ThinLinkWriter(M, StrtabBuilder, *Stream, Index,
4864                                        ModHash);
4865   ThinLinkWriter.write();
4866 }
4867 
4868 // Write the specified thin link bitcode file to the given raw output stream,
4869 // where it will be written in a new bitcode block. This is used when
4870 // writing the per-module index file for ThinLTO.
4871 void llvm::writeThinLinkBitcodeToFile(const Module &M, raw_ostream &Out,
4872                                       const ModuleSummaryIndex &Index,
4873                                       const ModuleHash &ModHash) {
4874   SmallVector<char, 0> Buffer;
4875   Buffer.reserve(256 * 1024);
4876 
4877   BitcodeWriter Writer(Buffer);
4878   Writer.writeThinLinkBitcode(M, Index, ModHash);
4879   Writer.writeSymtab();
4880   Writer.writeStrtab();
4881 
4882   Out.write((char *)&Buffer.front(), Buffer.size());
4883 }
4884 
4885 static const char *getSectionNameForBitcode(const Triple &T) {
4886   switch (T.getObjectFormat()) {
4887   case Triple::MachO:
4888     return "__LLVM,__bitcode";
4889   case Triple::COFF:
4890   case Triple::ELF:
4891   case Triple::Wasm:
4892   case Triple::UnknownObjectFormat:
4893     return ".llvmbc";
4894   case Triple::GOFF:
4895     llvm_unreachable("GOFF is not yet implemented");
4896     break;
4897   case Triple::SPIRV:
4898     llvm_unreachable("SPIRV is not yet implemented");
4899     break;
4900   case Triple::XCOFF:
4901     llvm_unreachable("XCOFF is not yet implemented");
4902     break;
4903   case Triple::DXContainer:
4904     llvm_unreachable("DXContainer is not yet implemented");
4905     break;
4906   }
4907   llvm_unreachable("Unimplemented ObjectFormatType");
4908 }
4909 
4910 static const char *getSectionNameForCommandline(const Triple &T) {
4911   switch (T.getObjectFormat()) {
4912   case Triple::MachO:
4913     return "__LLVM,__cmdline";
4914   case Triple::COFF:
4915   case Triple::ELF:
4916   case Triple::Wasm:
4917   case Triple::UnknownObjectFormat:
4918     return ".llvmcmd";
4919   case Triple::GOFF:
4920     llvm_unreachable("GOFF is not yet implemented");
4921     break;
4922   case Triple::SPIRV:
4923     llvm_unreachable("SPIRV is not yet implemented");
4924     break;
4925   case Triple::XCOFF:
4926     llvm_unreachable("XCOFF is not yet implemented");
4927     break;
4928   case Triple::DXContainer:
4929     llvm_unreachable("DXC is not yet implemented");
4930     break;
4931   }
4932   llvm_unreachable("Unimplemented ObjectFormatType");
4933 }
4934 
4935 void llvm::embedBitcodeInModule(llvm::Module &M, llvm::MemoryBufferRef Buf,
4936                                 bool EmbedBitcode, bool EmbedCmdline,
4937                                 const std::vector<uint8_t> &CmdArgs) {
4938   // Save llvm.compiler.used and remove it.
4939   SmallVector<Constant *, 2> UsedArray;
4940   SmallVector<GlobalValue *, 4> UsedGlobals;
4941   Type *UsedElementType = Type::getInt8Ty(M.getContext())->getPointerTo(0);
4942   GlobalVariable *Used = collectUsedGlobalVariables(M, UsedGlobals, true);
4943   for (auto *GV : UsedGlobals) {
4944     if (GV->getName() != "llvm.embedded.module" &&
4945         GV->getName() != "llvm.cmdline")
4946       UsedArray.push_back(
4947           ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
4948   }
4949   if (Used)
4950     Used->eraseFromParent();
4951 
4952   // Embed the bitcode for the llvm module.
4953   std::string Data;
4954   ArrayRef<uint8_t> ModuleData;
4955   Triple T(M.getTargetTriple());
4956 
4957   if (EmbedBitcode) {
4958     if (Buf.getBufferSize() == 0 ||
4959         !isBitcode((const unsigned char *)Buf.getBufferStart(),
4960                    (const unsigned char *)Buf.getBufferEnd())) {
4961       // If the input is LLVM Assembly, bitcode is produced by serializing
4962       // the module. Use-lists order need to be preserved in this case.
4963       llvm::raw_string_ostream OS(Data);
4964       llvm::WriteBitcodeToFile(M, OS, /* ShouldPreserveUseListOrder */ true);
4965       ModuleData =
4966           ArrayRef<uint8_t>((const uint8_t *)OS.str().data(), OS.str().size());
4967     } else
4968       // If the input is LLVM bitcode, write the input byte stream directly.
4969       ModuleData = ArrayRef<uint8_t>((const uint8_t *)Buf.getBufferStart(),
4970                                      Buf.getBufferSize());
4971   }
4972   llvm::Constant *ModuleConstant =
4973       llvm::ConstantDataArray::get(M.getContext(), ModuleData);
4974   llvm::GlobalVariable *GV = new llvm::GlobalVariable(
4975       M, ModuleConstant->getType(), true, llvm::GlobalValue::PrivateLinkage,
4976       ModuleConstant);
4977   GV->setSection(getSectionNameForBitcode(T));
4978   // Set alignment to 1 to prevent padding between two contributions from input
4979   // sections after linking.
4980   GV->setAlignment(Align(1));
4981   UsedArray.push_back(
4982       ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
4983   if (llvm::GlobalVariable *Old =
4984           M.getGlobalVariable("llvm.embedded.module", true)) {
4985     assert(Old->hasZeroLiveUses() &&
4986            "llvm.embedded.module can only be used once in llvm.compiler.used");
4987     GV->takeName(Old);
4988     Old->eraseFromParent();
4989   } else {
4990     GV->setName("llvm.embedded.module");
4991   }
4992 
4993   // Skip if only bitcode needs to be embedded.
4994   if (EmbedCmdline) {
4995     // Embed command-line options.
4996     ArrayRef<uint8_t> CmdData(const_cast<uint8_t *>(CmdArgs.data()),
4997                               CmdArgs.size());
4998     llvm::Constant *CmdConstant =
4999         llvm::ConstantDataArray::get(M.getContext(), CmdData);
5000     GV = new llvm::GlobalVariable(M, CmdConstant->getType(), true,
5001                                   llvm::GlobalValue::PrivateLinkage,
5002                                   CmdConstant);
5003     GV->setSection(getSectionNameForCommandline(T));
5004     GV->setAlignment(Align(1));
5005     UsedArray.push_back(
5006         ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
5007     if (llvm::GlobalVariable *Old = M.getGlobalVariable("llvm.cmdline", true)) {
5008       assert(Old->hasZeroLiveUses() &&
5009              "llvm.cmdline can only be used once in llvm.compiler.used");
5010       GV->takeName(Old);
5011       Old->eraseFromParent();
5012     } else {
5013       GV->setName("llvm.cmdline");
5014     }
5015   }
5016 
5017   if (UsedArray.empty())
5018     return;
5019 
5020   // Recreate llvm.compiler.used.
5021   ArrayType *ATy = ArrayType::get(UsedElementType, UsedArray.size());
5022   auto *NewUsed = new GlobalVariable(
5023       M, ATy, false, llvm::GlobalValue::AppendingLinkage,
5024       llvm::ConstantArray::get(ATy, UsedArray), "llvm.compiler.used");
5025   NewUsed->setSection("llvm.metadata");
5026 }
5027