1 //===- Bitcode/Writer/BitcodeWriter.cpp - Bitcode Writer ------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // Bitcode writer implementation.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "llvm/Bitcode/BitcodeWriter.h"
14 #include "ValueEnumerator.h"
15 #include "llvm/ADT/APFloat.h"
16 #include "llvm/ADT/APInt.h"
17 #include "llvm/ADT/ArrayRef.h"
18 #include "llvm/ADT/DenseMap.h"
19 #include "llvm/ADT/None.h"
20 #include "llvm/ADT/Optional.h"
21 #include "llvm/ADT/STLExtras.h"
22 #include "llvm/ADT/SmallString.h"
23 #include "llvm/ADT/SmallVector.h"
24 #include "llvm/ADT/StringMap.h"
25 #include "llvm/ADT/StringRef.h"
26 #include "llvm/ADT/Triple.h"
27 #include "llvm/Bitcode/BitcodeCommon.h"
28 #include "llvm/Bitcode/BitcodeReader.h"
29 #include "llvm/Bitcode/LLVMBitCodes.h"
30 #include "llvm/Bitstream/BitCodes.h"
31 #include "llvm/Bitstream/BitstreamWriter.h"
32 #include "llvm/Config/llvm-config.h"
33 #include "llvm/IR/Attributes.h"
34 #include "llvm/IR/BasicBlock.h"
35 #include "llvm/IR/Comdat.h"
36 #include "llvm/IR/Constant.h"
37 #include "llvm/IR/Constants.h"
38 #include "llvm/IR/DebugInfoMetadata.h"
39 #include "llvm/IR/DebugLoc.h"
40 #include "llvm/IR/DerivedTypes.h"
41 #include "llvm/IR/Function.h"
42 #include "llvm/IR/GlobalAlias.h"
43 #include "llvm/IR/GlobalIFunc.h"
44 #include "llvm/IR/GlobalObject.h"
45 #include "llvm/IR/GlobalValue.h"
46 #include "llvm/IR/GlobalVariable.h"
47 #include "llvm/IR/InlineAsm.h"
48 #include "llvm/IR/InstrTypes.h"
49 #include "llvm/IR/Instruction.h"
50 #include "llvm/IR/Instructions.h"
51 #include "llvm/IR/LLVMContext.h"
52 #include "llvm/IR/Metadata.h"
53 #include "llvm/IR/Module.h"
54 #include "llvm/IR/ModuleSummaryIndex.h"
55 #include "llvm/IR/Operator.h"
56 #include "llvm/IR/Type.h"
57 #include "llvm/IR/UseListOrder.h"
58 #include "llvm/IR/Value.h"
59 #include "llvm/IR/ValueSymbolTable.h"
60 #include "llvm/MC/StringTableBuilder.h"
61 #include "llvm/Object/IRSymtab.h"
62 #include "llvm/Support/AtomicOrdering.h"
63 #include "llvm/Support/Casting.h"
64 #include "llvm/Support/CommandLine.h"
65 #include "llvm/Support/Endian.h"
66 #include "llvm/Support/Error.h"
67 #include "llvm/Support/ErrorHandling.h"
68 #include "llvm/Support/MathExtras.h"
69 #include "llvm/Support/SHA1.h"
70 #include "llvm/Support/TargetRegistry.h"
71 #include "llvm/Support/raw_ostream.h"
72 #include <algorithm>
73 #include <cassert>
74 #include <cstddef>
75 #include <cstdint>
76 #include <iterator>
77 #include <map>
78 #include <memory>
79 #include <string>
80 #include <utility>
81 #include <vector>
82 
83 using namespace llvm;
84 
85 static cl::opt<unsigned>
86     IndexThreshold("bitcode-mdindex-threshold", cl::Hidden, cl::init(25),
87                    cl::desc("Number of metadatas above which we emit an index "
88                             "to enable lazy-loading"));
89 static cl::opt<uint32_t> FlushThreshold(
90     "bitcode-flush-threshold", cl::Hidden, cl::init(512),
91     cl::desc("The threshold (unit M) for flushing LLVM bitcode."));
92 
93 static cl::opt<bool> WriteRelBFToSummary(
94     "write-relbf-to-summary", cl::Hidden, cl::init(false),
95     cl::desc("Write relative block frequency to function summary "));
96 
97 extern FunctionSummary::ForceSummaryHotnessType ForceSummaryEdgesCold;
98 
99 namespace {
100 
101 /// These are manifest constants used by the bitcode writer. They do not need to
102 /// be kept in sync with the reader, but need to be consistent within this file.
103 enum {
104   // VALUE_SYMTAB_BLOCK abbrev id's.
105   VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
106   VST_ENTRY_7_ABBREV,
107   VST_ENTRY_6_ABBREV,
108   VST_BBENTRY_6_ABBREV,
109 
110   // CONSTANTS_BLOCK abbrev id's.
111   CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
112   CONSTANTS_INTEGER_ABBREV,
113   CONSTANTS_CE_CAST_Abbrev,
114   CONSTANTS_NULL_Abbrev,
115 
116   // FUNCTION_BLOCK abbrev id's.
117   FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
118   FUNCTION_INST_UNOP_ABBREV,
119   FUNCTION_INST_UNOP_FLAGS_ABBREV,
120   FUNCTION_INST_BINOP_ABBREV,
121   FUNCTION_INST_BINOP_FLAGS_ABBREV,
122   FUNCTION_INST_CAST_ABBREV,
123   FUNCTION_INST_RET_VOID_ABBREV,
124   FUNCTION_INST_RET_VAL_ABBREV,
125   FUNCTION_INST_UNREACHABLE_ABBREV,
126   FUNCTION_INST_GEP_ABBREV,
127 };
128 
129 /// Abstract class to manage the bitcode writing, subclassed for each bitcode
130 /// file type.
131 class BitcodeWriterBase {
132 protected:
133   /// The stream created and owned by the client.
134   BitstreamWriter &Stream;
135 
136   StringTableBuilder &StrtabBuilder;
137 
138 public:
139   /// Constructs a BitcodeWriterBase object that writes to the provided
140   /// \p Stream.
141   BitcodeWriterBase(BitstreamWriter &Stream, StringTableBuilder &StrtabBuilder)
142       : Stream(Stream), StrtabBuilder(StrtabBuilder) {}
143 
144 protected:
145   void writeBitcodeHeader();
146   void writeModuleVersion();
147 };
148 
149 void BitcodeWriterBase::writeModuleVersion() {
150   // VERSION: [version#]
151   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, ArrayRef<uint64_t>{2});
152 }
153 
154 /// Base class to manage the module bitcode writing, currently subclassed for
155 /// ModuleBitcodeWriter and ThinLinkBitcodeWriter.
156 class ModuleBitcodeWriterBase : public BitcodeWriterBase {
157 protected:
158   /// The Module to write to bitcode.
159   const Module &M;
160 
161   /// Enumerates ids for all values in the module.
162   ValueEnumerator VE;
163 
164   /// Optional per-module index to write for ThinLTO.
165   const ModuleSummaryIndex *Index;
166 
167   /// Map that holds the correspondence between GUIDs in the summary index,
168   /// that came from indirect call profiles, and a value id generated by this
169   /// class to use in the VST and summary block records.
170   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
171 
172   /// Tracks the last value id recorded in the GUIDToValueMap.
173   unsigned GlobalValueId;
174 
175   /// Saves the offset of the VSTOffset record that must eventually be
176   /// backpatched with the offset of the actual VST.
177   uint64_t VSTOffsetPlaceholder = 0;
178 
179 public:
180   /// Constructs a ModuleBitcodeWriterBase object for the given Module,
181   /// writing to the provided \p Buffer.
182   ModuleBitcodeWriterBase(const Module &M, StringTableBuilder &StrtabBuilder,
183                           BitstreamWriter &Stream,
184                           bool ShouldPreserveUseListOrder,
185                           const ModuleSummaryIndex *Index)
186       : BitcodeWriterBase(Stream, StrtabBuilder), M(M),
187         VE(M, ShouldPreserveUseListOrder), Index(Index) {
188     // Assign ValueIds to any callee values in the index that came from
189     // indirect call profiles and were recorded as a GUID not a Value*
190     // (which would have been assigned an ID by the ValueEnumerator).
191     // The starting ValueId is just after the number of values in the
192     // ValueEnumerator, so that they can be emitted in the VST.
193     GlobalValueId = VE.getValues().size();
194     if (!Index)
195       return;
196     for (const auto &GUIDSummaryLists : *Index)
197       // Examine all summaries for this GUID.
198       for (auto &Summary : GUIDSummaryLists.second.SummaryList)
199         if (auto FS = dyn_cast<FunctionSummary>(Summary.get()))
200           // For each call in the function summary, see if the call
201           // is to a GUID (which means it is for an indirect call,
202           // otherwise we would have a Value for it). If so, synthesize
203           // a value id.
204           for (auto &CallEdge : FS->calls())
205             if (!CallEdge.first.haveGVs() || !CallEdge.first.getValue())
206               assignValueId(CallEdge.first.getGUID());
207   }
208 
209 protected:
210   void writePerModuleGlobalValueSummary();
211 
212 private:
213   void writePerModuleFunctionSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
214                                            GlobalValueSummary *Summary,
215                                            unsigned ValueID,
216                                            unsigned FSCallsAbbrev,
217                                            unsigned FSCallsProfileAbbrev,
218                                            const Function &F);
219   void writeModuleLevelReferences(const GlobalVariable &V,
220                                   SmallVector<uint64_t, 64> &NameVals,
221                                   unsigned FSModRefsAbbrev,
222                                   unsigned FSModVTableRefsAbbrev);
223 
224   void assignValueId(GlobalValue::GUID ValGUID) {
225     GUIDToValueIdMap[ValGUID] = ++GlobalValueId;
226   }
227 
228   unsigned getValueId(GlobalValue::GUID ValGUID) {
229     const auto &VMI = GUIDToValueIdMap.find(ValGUID);
230     // Expect that any GUID value had a value Id assigned by an
231     // earlier call to assignValueId.
232     assert(VMI != GUIDToValueIdMap.end() &&
233            "GUID does not have assigned value Id");
234     return VMI->second;
235   }
236 
237   // Helper to get the valueId for the type of value recorded in VI.
238   unsigned getValueId(ValueInfo VI) {
239     if (!VI.haveGVs() || !VI.getValue())
240       return getValueId(VI.getGUID());
241     return VE.getValueID(VI.getValue());
242   }
243 
244   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
245 };
246 
247 /// Class to manage the bitcode writing for a module.
248 class ModuleBitcodeWriter : public ModuleBitcodeWriterBase {
249   /// Pointer to the buffer allocated by caller for bitcode writing.
250   const SmallVectorImpl<char> &Buffer;
251 
252   /// True if a module hash record should be written.
253   bool GenerateHash;
254 
255   /// If non-null, when GenerateHash is true, the resulting hash is written
256   /// into ModHash.
257   ModuleHash *ModHash;
258 
259   SHA1 Hasher;
260 
261   /// The start bit of the identification block.
262   uint64_t BitcodeStartBit;
263 
264 public:
265   /// Constructs a ModuleBitcodeWriter object for the given Module,
266   /// writing to the provided \p Buffer.
267   ModuleBitcodeWriter(const Module &M, SmallVectorImpl<char> &Buffer,
268                       StringTableBuilder &StrtabBuilder,
269                       BitstreamWriter &Stream, bool ShouldPreserveUseListOrder,
270                       const ModuleSummaryIndex *Index, bool GenerateHash,
271                       ModuleHash *ModHash = nullptr)
272       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
273                                 ShouldPreserveUseListOrder, Index),
274         Buffer(Buffer), GenerateHash(GenerateHash), ModHash(ModHash),
275         BitcodeStartBit(Stream.GetCurrentBitNo()) {}
276 
277   /// Emit the current module to the bitstream.
278   void write();
279 
280 private:
281   uint64_t bitcodeStartBit() { return BitcodeStartBit; }
282 
283   size_t addToStrtab(StringRef Str);
284 
285   void writeAttributeGroupTable();
286   void writeAttributeTable();
287   void writeTypeTable();
288   void writeComdats();
289   void writeValueSymbolTableForwardDecl();
290   void writeModuleInfo();
291   void writeValueAsMetadata(const ValueAsMetadata *MD,
292                             SmallVectorImpl<uint64_t> &Record);
293   void writeMDTuple(const MDTuple *N, SmallVectorImpl<uint64_t> &Record,
294                     unsigned Abbrev);
295   unsigned createDILocationAbbrev();
296   void writeDILocation(const DILocation *N, SmallVectorImpl<uint64_t> &Record,
297                        unsigned &Abbrev);
298   unsigned createGenericDINodeAbbrev();
299   void writeGenericDINode(const GenericDINode *N,
300                           SmallVectorImpl<uint64_t> &Record, unsigned &Abbrev);
301   void writeDISubrange(const DISubrange *N, SmallVectorImpl<uint64_t> &Record,
302                        unsigned Abbrev);
303   void 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 writeGlobalVariableMetadataAttachment(const GlobalVariable &GV);
378   void pushGlobalMetadataAttachment(SmallVectorImpl<uint64_t> &Record,
379                                     const GlobalObject &GO);
380   void writeModuleMetadataKinds();
381   void writeOperandBundleTags();
382   void writeSyncScopeNames();
383   void writeConstants(unsigned FirstVal, unsigned LastVal, bool isGlobal);
384   void writeModuleConstants();
385   bool pushValueAndType(const Value *V, unsigned InstID,
386                         SmallVectorImpl<unsigned> &Vals);
387   void writeOperandBundles(const CallBase &CB, unsigned InstID);
388   void pushValue(const Value *V, unsigned InstID,
389                  SmallVectorImpl<unsigned> &Vals);
390   void pushValueSigned(const Value *V, unsigned InstID,
391                        SmallVectorImpl<uint64_t> &Vals);
392   void writeInstruction(const Instruction &I, unsigned InstID,
393                         SmallVectorImpl<unsigned> &Vals);
394   void writeFunctionLevelValueSymbolTable(const ValueSymbolTable &VST);
395   void writeGlobalValueSymbolTable(
396       DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
397   void writeUseList(UseListOrder &&Order);
398   void writeUseListBlock(const Function *F);
399   void
400   writeFunction(const Function &F,
401                 DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
402   void writeBlockInfo();
403   void writeModuleHash(size_t BlockStartPos);
404 
405   unsigned getEncodedSyncScopeID(SyncScope::ID SSID) {
406     return unsigned(SSID);
407   }
408 
409   unsigned getEncodedAlign(MaybeAlign Alignment) { return encode(Alignment); }
410 };
411 
412 /// Class to manage the bitcode writing for a combined index.
413 class IndexBitcodeWriter : public BitcodeWriterBase {
414   /// The combined index to write to bitcode.
415   const ModuleSummaryIndex &Index;
416 
417   /// When writing a subset of the index for distributed backends, client
418   /// provides a map of modules to the corresponding GUIDs/summaries to write.
419   const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex;
420 
421   /// Map that holds the correspondence between the GUID used in the combined
422   /// index and a value id generated by this class to use in references.
423   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
424 
425   /// Tracks the last value id recorded in the GUIDToValueMap.
426   unsigned GlobalValueId = 0;
427 
428 public:
429   /// Constructs a IndexBitcodeWriter object for the given combined index,
430   /// writing to the provided \p Buffer. When writing a subset of the index
431   /// for a distributed backend, provide a \p ModuleToSummariesForIndex map.
432   IndexBitcodeWriter(BitstreamWriter &Stream, StringTableBuilder &StrtabBuilder,
433                      const ModuleSummaryIndex &Index,
434                      const std::map<std::string, GVSummaryMapTy>
435                          *ModuleToSummariesForIndex = nullptr)
436       : BitcodeWriterBase(Stream, StrtabBuilder), Index(Index),
437         ModuleToSummariesForIndex(ModuleToSummariesForIndex) {
438     // Assign unique value ids to all summaries to be written, for use
439     // in writing out the call graph edges. Save the mapping from GUID
440     // to the new global value id to use when writing those edges, which
441     // are currently saved in the index in terms of GUID.
442     forEachSummary([&](GVInfo I, bool) {
443       GUIDToValueIdMap[I.first] = ++GlobalValueId;
444     });
445   }
446 
447   /// The below iterator returns the GUID and associated summary.
448   using GVInfo = std::pair<GlobalValue::GUID, GlobalValueSummary *>;
449 
450   /// Calls the callback for each value GUID and summary to be written to
451   /// bitcode. This hides the details of whether they are being pulled from the
452   /// entire index or just those in a provided ModuleToSummariesForIndex map.
453   template<typename Functor>
454   void forEachSummary(Functor Callback) {
455     if (ModuleToSummariesForIndex) {
456       for (auto &M : *ModuleToSummariesForIndex)
457         for (auto &Summary : M.second) {
458           Callback(Summary, false);
459           // Ensure aliasee is handled, e.g. for assigning a valueId,
460           // even if we are not importing the aliasee directly (the
461           // imported alias will contain a copy of aliasee).
462           if (auto *AS = dyn_cast<AliasSummary>(Summary.getSecond()))
463             Callback({AS->getAliaseeGUID(), &AS->getAliasee()}, true);
464         }
465     } else {
466       for (auto &Summaries : Index)
467         for (auto &Summary : Summaries.second.SummaryList)
468           Callback({Summaries.first, Summary.get()}, false);
469     }
470   }
471 
472   /// Calls the callback for each entry in the modulePaths StringMap that
473   /// should be written to the module path string table. This hides the details
474   /// of whether they are being pulled from the entire index or just those in a
475   /// provided ModuleToSummariesForIndex map.
476   template <typename Functor> void forEachModule(Functor Callback) {
477     if (ModuleToSummariesForIndex) {
478       for (const auto &M : *ModuleToSummariesForIndex) {
479         const auto &MPI = Index.modulePaths().find(M.first);
480         if (MPI == Index.modulePaths().end()) {
481           // This should only happen if the bitcode file was empty, in which
482           // case we shouldn't be importing (the ModuleToSummariesForIndex
483           // would only include the module we are writing and index for).
484           assert(ModuleToSummariesForIndex->size() == 1);
485           continue;
486         }
487         Callback(*MPI);
488       }
489     } else {
490       for (const auto &MPSE : Index.modulePaths())
491         Callback(MPSE);
492     }
493   }
494 
495   /// Main entry point for writing a combined index to bitcode.
496   void write();
497 
498 private:
499   void writeModStrings();
500   void writeCombinedGlobalValueSummary();
501 
502   Optional<unsigned> getValueId(GlobalValue::GUID ValGUID) {
503     auto VMI = GUIDToValueIdMap.find(ValGUID);
504     if (VMI == GUIDToValueIdMap.end())
505       return None;
506     return VMI->second;
507   }
508 
509   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
510 };
511 
512 } // end anonymous namespace
513 
514 static unsigned getEncodedCastOpcode(unsigned Opcode) {
515   switch (Opcode) {
516   default: llvm_unreachable("Unknown cast instruction!");
517   case Instruction::Trunc   : return bitc::CAST_TRUNC;
518   case Instruction::ZExt    : return bitc::CAST_ZEXT;
519   case Instruction::SExt    : return bitc::CAST_SEXT;
520   case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
521   case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
522   case Instruction::UIToFP  : return bitc::CAST_UITOFP;
523   case Instruction::SIToFP  : return bitc::CAST_SITOFP;
524   case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
525   case Instruction::FPExt   : return bitc::CAST_FPEXT;
526   case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
527   case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
528   case Instruction::BitCast : return bitc::CAST_BITCAST;
529   case Instruction::AddrSpaceCast: return bitc::CAST_ADDRSPACECAST;
530   }
531 }
532 
533 static unsigned getEncodedUnaryOpcode(unsigned Opcode) {
534   switch (Opcode) {
535   default: llvm_unreachable("Unknown binary instruction!");
536   case Instruction::FNeg: return bitc::UNOP_FNEG;
537   }
538 }
539 
540 static unsigned getEncodedBinaryOpcode(unsigned Opcode) {
541   switch (Opcode) {
542   default: llvm_unreachable("Unknown binary instruction!");
543   case Instruction::Add:
544   case Instruction::FAdd: return bitc::BINOP_ADD;
545   case Instruction::Sub:
546   case Instruction::FSub: return bitc::BINOP_SUB;
547   case Instruction::Mul:
548   case Instruction::FMul: return bitc::BINOP_MUL;
549   case Instruction::UDiv: return bitc::BINOP_UDIV;
550   case Instruction::FDiv:
551   case Instruction::SDiv: return bitc::BINOP_SDIV;
552   case Instruction::URem: return bitc::BINOP_UREM;
553   case Instruction::FRem:
554   case Instruction::SRem: return bitc::BINOP_SREM;
555   case Instruction::Shl:  return bitc::BINOP_SHL;
556   case Instruction::LShr: return bitc::BINOP_LSHR;
557   case Instruction::AShr: return bitc::BINOP_ASHR;
558   case Instruction::And:  return bitc::BINOP_AND;
559   case Instruction::Or:   return bitc::BINOP_OR;
560   case Instruction::Xor:  return bitc::BINOP_XOR;
561   }
562 }
563 
564 static unsigned getEncodedRMWOperation(AtomicRMWInst::BinOp Op) {
565   switch (Op) {
566   default: llvm_unreachable("Unknown RMW operation!");
567   case AtomicRMWInst::Xchg: return bitc::RMW_XCHG;
568   case AtomicRMWInst::Add: return bitc::RMW_ADD;
569   case AtomicRMWInst::Sub: return bitc::RMW_SUB;
570   case AtomicRMWInst::And: return bitc::RMW_AND;
571   case AtomicRMWInst::Nand: return bitc::RMW_NAND;
572   case AtomicRMWInst::Or: return bitc::RMW_OR;
573   case AtomicRMWInst::Xor: return bitc::RMW_XOR;
574   case AtomicRMWInst::Max: return bitc::RMW_MAX;
575   case AtomicRMWInst::Min: return bitc::RMW_MIN;
576   case AtomicRMWInst::UMax: return bitc::RMW_UMAX;
577   case AtomicRMWInst::UMin: return bitc::RMW_UMIN;
578   case AtomicRMWInst::FAdd: return bitc::RMW_FADD;
579   case AtomicRMWInst::FSub: return bitc::RMW_FSUB;
580   }
581 }
582 
583 static unsigned getEncodedOrdering(AtomicOrdering Ordering) {
584   switch (Ordering) {
585   case AtomicOrdering::NotAtomic: return bitc::ORDERING_NOTATOMIC;
586   case AtomicOrdering::Unordered: return bitc::ORDERING_UNORDERED;
587   case AtomicOrdering::Monotonic: return bitc::ORDERING_MONOTONIC;
588   case AtomicOrdering::Acquire: return bitc::ORDERING_ACQUIRE;
589   case AtomicOrdering::Release: return bitc::ORDERING_RELEASE;
590   case AtomicOrdering::AcquireRelease: return bitc::ORDERING_ACQREL;
591   case AtomicOrdering::SequentiallyConsistent: return bitc::ORDERING_SEQCST;
592   }
593   llvm_unreachable("Invalid ordering");
594 }
595 
596 static void writeStringRecord(BitstreamWriter &Stream, unsigned Code,
597                               StringRef Str, unsigned AbbrevToUse) {
598   SmallVector<unsigned, 64> Vals;
599 
600   // Code: [strchar x N]
601   for (unsigned i = 0, e = Str.size(); i != e; ++i) {
602     if (AbbrevToUse && !BitCodeAbbrevOp::isChar6(Str[i]))
603       AbbrevToUse = 0;
604     Vals.push_back(Str[i]);
605   }
606 
607   // Emit the finished record.
608   Stream.EmitRecord(Code, Vals, AbbrevToUse);
609 }
610 
611 static uint64_t getAttrKindEncoding(Attribute::AttrKind Kind) {
612   switch (Kind) {
613   case Attribute::Alignment:
614     return bitc::ATTR_KIND_ALIGNMENT;
615   case Attribute::AllocSize:
616     return bitc::ATTR_KIND_ALLOC_SIZE;
617   case Attribute::AlwaysInline:
618     return bitc::ATTR_KIND_ALWAYS_INLINE;
619   case Attribute::ArgMemOnly:
620     return bitc::ATTR_KIND_ARGMEMONLY;
621   case Attribute::Builtin:
622     return bitc::ATTR_KIND_BUILTIN;
623   case Attribute::ByVal:
624     return bitc::ATTR_KIND_BY_VAL;
625   case Attribute::Convergent:
626     return bitc::ATTR_KIND_CONVERGENT;
627   case Attribute::InAlloca:
628     return bitc::ATTR_KIND_IN_ALLOCA;
629   case Attribute::Cold:
630     return bitc::ATTR_KIND_COLD;
631   case Attribute::Hot:
632     return bitc::ATTR_KIND_HOT;
633   case Attribute::InaccessibleMemOnly:
634     return bitc::ATTR_KIND_INACCESSIBLEMEM_ONLY;
635   case Attribute::InaccessibleMemOrArgMemOnly:
636     return bitc::ATTR_KIND_INACCESSIBLEMEM_OR_ARGMEMONLY;
637   case Attribute::InlineHint:
638     return bitc::ATTR_KIND_INLINE_HINT;
639   case Attribute::InReg:
640     return bitc::ATTR_KIND_IN_REG;
641   case Attribute::JumpTable:
642     return bitc::ATTR_KIND_JUMP_TABLE;
643   case Attribute::MinSize:
644     return bitc::ATTR_KIND_MIN_SIZE;
645   case Attribute::Naked:
646     return bitc::ATTR_KIND_NAKED;
647   case Attribute::Nest:
648     return bitc::ATTR_KIND_NEST;
649   case Attribute::NoAlias:
650     return bitc::ATTR_KIND_NO_ALIAS;
651   case Attribute::NoBuiltin:
652     return bitc::ATTR_KIND_NO_BUILTIN;
653   case Attribute::NoCallback:
654     return bitc::ATTR_KIND_NO_CALLBACK;
655   case Attribute::NoCapture:
656     return bitc::ATTR_KIND_NO_CAPTURE;
657   case Attribute::NoDuplicate:
658     return bitc::ATTR_KIND_NO_DUPLICATE;
659   case Attribute::NoFree:
660     return bitc::ATTR_KIND_NOFREE;
661   case Attribute::NoImplicitFloat:
662     return bitc::ATTR_KIND_NO_IMPLICIT_FLOAT;
663   case Attribute::NoInline:
664     return bitc::ATTR_KIND_NO_INLINE;
665   case Attribute::NoRecurse:
666     return bitc::ATTR_KIND_NO_RECURSE;
667   case Attribute::NoMerge:
668     return bitc::ATTR_KIND_NO_MERGE;
669   case Attribute::NonLazyBind:
670     return bitc::ATTR_KIND_NON_LAZY_BIND;
671   case Attribute::NonNull:
672     return bitc::ATTR_KIND_NON_NULL;
673   case Attribute::Dereferenceable:
674     return bitc::ATTR_KIND_DEREFERENCEABLE;
675   case Attribute::DereferenceableOrNull:
676     return bitc::ATTR_KIND_DEREFERENCEABLE_OR_NULL;
677   case Attribute::NoRedZone:
678     return bitc::ATTR_KIND_NO_RED_ZONE;
679   case Attribute::NoReturn:
680     return bitc::ATTR_KIND_NO_RETURN;
681   case Attribute::NoSync:
682     return bitc::ATTR_KIND_NOSYNC;
683   case Attribute::NoCfCheck:
684     return bitc::ATTR_KIND_NOCF_CHECK;
685   case Attribute::NoProfile:
686     return bitc::ATTR_KIND_NO_PROFILE;
687   case Attribute::NoUnwind:
688     return bitc::ATTR_KIND_NO_UNWIND;
689   case Attribute::NullPointerIsValid:
690     return bitc::ATTR_KIND_NULL_POINTER_IS_VALID;
691   case Attribute::OptForFuzzing:
692     return bitc::ATTR_KIND_OPT_FOR_FUZZING;
693   case Attribute::OptimizeForSize:
694     return bitc::ATTR_KIND_OPTIMIZE_FOR_SIZE;
695   case Attribute::OptimizeNone:
696     return bitc::ATTR_KIND_OPTIMIZE_NONE;
697   case Attribute::ReadNone:
698     return bitc::ATTR_KIND_READ_NONE;
699   case Attribute::ReadOnly:
700     return bitc::ATTR_KIND_READ_ONLY;
701   case Attribute::Returned:
702     return bitc::ATTR_KIND_RETURNED;
703   case Attribute::ReturnsTwice:
704     return bitc::ATTR_KIND_RETURNS_TWICE;
705   case Attribute::SExt:
706     return bitc::ATTR_KIND_S_EXT;
707   case Attribute::Speculatable:
708     return bitc::ATTR_KIND_SPECULATABLE;
709   case Attribute::StackAlignment:
710     return bitc::ATTR_KIND_STACK_ALIGNMENT;
711   case Attribute::StackProtect:
712     return bitc::ATTR_KIND_STACK_PROTECT;
713   case Attribute::StackProtectReq:
714     return bitc::ATTR_KIND_STACK_PROTECT_REQ;
715   case Attribute::StackProtectStrong:
716     return bitc::ATTR_KIND_STACK_PROTECT_STRONG;
717   case Attribute::SafeStack:
718     return bitc::ATTR_KIND_SAFESTACK;
719   case Attribute::ShadowCallStack:
720     return bitc::ATTR_KIND_SHADOWCALLSTACK;
721   case Attribute::StrictFP:
722     return bitc::ATTR_KIND_STRICT_FP;
723   case Attribute::StructRet:
724     return bitc::ATTR_KIND_STRUCT_RET;
725   case Attribute::SanitizeAddress:
726     return bitc::ATTR_KIND_SANITIZE_ADDRESS;
727   case Attribute::SanitizeHWAddress:
728     return bitc::ATTR_KIND_SANITIZE_HWADDRESS;
729   case Attribute::SanitizeThread:
730     return bitc::ATTR_KIND_SANITIZE_THREAD;
731   case Attribute::SanitizeMemory:
732     return bitc::ATTR_KIND_SANITIZE_MEMORY;
733   case Attribute::SpeculativeLoadHardening:
734     return bitc::ATTR_KIND_SPECULATIVE_LOAD_HARDENING;
735   case Attribute::SwiftError:
736     return bitc::ATTR_KIND_SWIFT_ERROR;
737   case Attribute::SwiftSelf:
738     return bitc::ATTR_KIND_SWIFT_SELF;
739   case Attribute::UWTable:
740     return bitc::ATTR_KIND_UW_TABLE;
741   case Attribute::VScaleRange:
742     return bitc::ATTR_KIND_VSCALE_RANGE;
743   case Attribute::WillReturn:
744     return bitc::ATTR_KIND_WILLRETURN;
745   case Attribute::WriteOnly:
746     return bitc::ATTR_KIND_WRITEONLY;
747   case Attribute::ZExt:
748     return bitc::ATTR_KIND_Z_EXT;
749   case Attribute::ImmArg:
750     return bitc::ATTR_KIND_IMMARG;
751   case Attribute::SanitizeMemTag:
752     return bitc::ATTR_KIND_SANITIZE_MEMTAG;
753   case Attribute::Preallocated:
754     return bitc::ATTR_KIND_PREALLOCATED;
755   case Attribute::NoUndef:
756     return bitc::ATTR_KIND_NOUNDEF;
757   case Attribute::ByRef:
758     return bitc::ATTR_KIND_BYREF;
759   case Attribute::MustProgress:
760     return bitc::ATTR_KIND_MUSTPROGRESS;
761   case Attribute::EndAttrKinds:
762     llvm_unreachable("Can not encode end-attribute kinds marker.");
763   case Attribute::None:
764     llvm_unreachable("Can not encode none-attribute.");
765   case Attribute::EmptyKey:
766   case Attribute::TombstoneKey:
767     llvm_unreachable("Trying to encode EmptyKey/TombstoneKey");
768   }
769 
770   llvm_unreachable("Trying to encode unknown attribute");
771 }
772 
773 void ModuleBitcodeWriter::writeAttributeGroupTable() {
774   const std::vector<ValueEnumerator::IndexAndAttrSet> &AttrGrps =
775       VE.getAttributeGroups();
776   if (AttrGrps.empty()) return;
777 
778   Stream.EnterSubblock(bitc::PARAMATTR_GROUP_BLOCK_ID, 3);
779 
780   SmallVector<uint64_t, 64> Record;
781   for (ValueEnumerator::IndexAndAttrSet Pair : AttrGrps) {
782     unsigned AttrListIndex = Pair.first;
783     AttributeSet AS = Pair.second;
784     Record.push_back(VE.getAttributeGroupID(Pair));
785     Record.push_back(AttrListIndex);
786 
787     for (Attribute Attr : AS) {
788       if (Attr.isEnumAttribute()) {
789         Record.push_back(0);
790         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
791       } else if (Attr.isIntAttribute()) {
792         Record.push_back(1);
793         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
794         Record.push_back(Attr.getValueAsInt());
795       } else if (Attr.isStringAttribute()) {
796         StringRef Kind = Attr.getKindAsString();
797         StringRef Val = Attr.getValueAsString();
798 
799         Record.push_back(Val.empty() ? 3 : 4);
800         Record.append(Kind.begin(), Kind.end());
801         Record.push_back(0);
802         if (!Val.empty()) {
803           Record.append(Val.begin(), Val.end());
804           Record.push_back(0);
805         }
806       } else {
807         assert(Attr.isTypeAttribute());
808         Type *Ty = Attr.getValueAsType();
809         Record.push_back(Ty ? 6 : 5);
810         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
811         if (Ty)
812           Record.push_back(VE.getTypeID(Attr.getValueAsType()));
813       }
814     }
815 
816     Stream.EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
817     Record.clear();
818   }
819 
820   Stream.ExitBlock();
821 }
822 
823 void ModuleBitcodeWriter::writeAttributeTable() {
824   const std::vector<AttributeList> &Attrs = VE.getAttributeLists();
825   if (Attrs.empty()) return;
826 
827   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
828 
829   SmallVector<uint64_t, 64> Record;
830   for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
831     AttributeList AL = Attrs[i];
832     for (unsigned i = AL.index_begin(), e = AL.index_end(); i != e; ++i) {
833       AttributeSet AS = AL.getAttributes(i);
834       if (AS.hasAttributes())
835         Record.push_back(VE.getAttributeGroupID({i, AS}));
836     }
837 
838     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
839     Record.clear();
840   }
841 
842   Stream.ExitBlock();
843 }
844 
845 /// WriteTypeTable - Write out the type table for a module.
846 void ModuleBitcodeWriter::writeTypeTable() {
847   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
848 
849   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
850   SmallVector<uint64_t, 64> TypeVals;
851 
852   uint64_t NumBits = VE.computeBitsRequiredForTypeIndicies();
853 
854   // Abbrev for TYPE_CODE_POINTER.
855   auto Abbv = std::make_shared<BitCodeAbbrev>();
856   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
857   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
858   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
859   unsigned PtrAbbrev = Stream.EmitAbbrev(std::move(Abbv));
860 
861   // Abbrev for TYPE_CODE_OPAQUE_POINTER.
862   Abbv = std::make_shared<BitCodeAbbrev>();
863   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_OPAQUE_POINTER));
864   Abbv->Add(BitCodeAbbrevOp(0)); // Addrspace = 0
865   unsigned OpaquePtrAbbrev = Stream.EmitAbbrev(std::move(Abbv));
866 
867   // Abbrev for TYPE_CODE_FUNCTION.
868   Abbv = std::make_shared<BitCodeAbbrev>();
869   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
870   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
871   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
872   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
873   unsigned FunctionAbbrev = Stream.EmitAbbrev(std::move(Abbv));
874 
875   // Abbrev for TYPE_CODE_STRUCT_ANON.
876   Abbv = std::make_shared<BitCodeAbbrev>();
877   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
878   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
879   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
880   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
881   unsigned StructAnonAbbrev = Stream.EmitAbbrev(std::move(Abbv));
882 
883   // Abbrev for TYPE_CODE_STRUCT_NAME.
884   Abbv = std::make_shared<BitCodeAbbrev>();
885   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
886   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
887   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
888   unsigned StructNameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
889 
890   // Abbrev for TYPE_CODE_STRUCT_NAMED.
891   Abbv = std::make_shared<BitCodeAbbrev>();
892   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
893   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
894   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
895   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
896   unsigned StructNamedAbbrev = Stream.EmitAbbrev(std::move(Abbv));
897 
898   // Abbrev for TYPE_CODE_ARRAY.
899   Abbv = std::make_shared<BitCodeAbbrev>();
900   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
901   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
902   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
903   unsigned ArrayAbbrev = Stream.EmitAbbrev(std::move(Abbv));
904 
905   // Emit an entry count so the reader can reserve space.
906   TypeVals.push_back(TypeList.size());
907   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
908   TypeVals.clear();
909 
910   // Loop over all of the types, emitting each in turn.
911   for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
912     Type *T = TypeList[i];
913     int AbbrevToUse = 0;
914     unsigned Code = 0;
915 
916     switch (T->getTypeID()) {
917     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;      break;
918     case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;      break;
919     case Type::BFloatTyID:    Code = bitc::TYPE_CODE_BFLOAT;    break;
920     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;     break;
921     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE;    break;
922     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80;  break;
923     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128;     break;
924     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
925     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;     break;
926     case Type::MetadataTyID:  Code = bitc::TYPE_CODE_METADATA;  break;
927     case Type::X86_MMXTyID:   Code = bitc::TYPE_CODE_X86_MMX;   break;
928     case Type::X86_AMXTyID:   Code = bitc::TYPE_CODE_X86_AMX;   break;
929     case Type::TokenTyID:     Code = bitc::TYPE_CODE_TOKEN;     break;
930     case Type::IntegerTyID:
931       // INTEGER: [width]
932       Code = bitc::TYPE_CODE_INTEGER;
933       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
934       break;
935     case Type::PointerTyID: {
936       PointerType *PTy = cast<PointerType>(T);
937       unsigned AddressSpace = PTy->getAddressSpace();
938       if (PTy->isOpaque()) {
939         // OPAQUE_POINTER: [address space]
940         Code = bitc::TYPE_CODE_OPAQUE_POINTER;
941         TypeVals.push_back(AddressSpace);
942         if (AddressSpace == 0)
943           AbbrevToUse = OpaquePtrAbbrev;
944       } else {
945         // POINTER: [pointee type, address space]
946         Code = bitc::TYPE_CODE_POINTER;
947         TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
948         TypeVals.push_back(AddressSpace);
949         if (AddressSpace == 0)
950           AbbrevToUse = PtrAbbrev;
951       }
952       break;
953     }
954     case Type::FunctionTyID: {
955       FunctionType *FT = cast<FunctionType>(T);
956       // FUNCTION: [isvararg, retty, paramty x N]
957       Code = bitc::TYPE_CODE_FUNCTION;
958       TypeVals.push_back(FT->isVarArg());
959       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
960       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
961         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
962       AbbrevToUse = FunctionAbbrev;
963       break;
964     }
965     case Type::StructTyID: {
966       StructType *ST = cast<StructType>(T);
967       // STRUCT: [ispacked, eltty x N]
968       TypeVals.push_back(ST->isPacked());
969       // Output all of the element types.
970       for (StructType::element_iterator I = ST->element_begin(),
971            E = ST->element_end(); I != E; ++I)
972         TypeVals.push_back(VE.getTypeID(*I));
973 
974       if (ST->isLiteral()) {
975         Code = bitc::TYPE_CODE_STRUCT_ANON;
976         AbbrevToUse = StructAnonAbbrev;
977       } else {
978         if (ST->isOpaque()) {
979           Code = bitc::TYPE_CODE_OPAQUE;
980         } else {
981           Code = bitc::TYPE_CODE_STRUCT_NAMED;
982           AbbrevToUse = StructNamedAbbrev;
983         }
984 
985         // Emit the name if it is present.
986         if (!ST->getName().empty())
987           writeStringRecord(Stream, bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
988                             StructNameAbbrev);
989       }
990       break;
991     }
992     case Type::ArrayTyID: {
993       ArrayType *AT = cast<ArrayType>(T);
994       // ARRAY: [numelts, eltty]
995       Code = bitc::TYPE_CODE_ARRAY;
996       TypeVals.push_back(AT->getNumElements());
997       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
998       AbbrevToUse = ArrayAbbrev;
999       break;
1000     }
1001     case Type::FixedVectorTyID:
1002     case Type::ScalableVectorTyID: {
1003       VectorType *VT = cast<VectorType>(T);
1004       // VECTOR [numelts, eltty] or
1005       //        [numelts, eltty, scalable]
1006       Code = bitc::TYPE_CODE_VECTOR;
1007       TypeVals.push_back(VT->getElementCount().getKnownMinValue());
1008       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
1009       if (isa<ScalableVectorType>(VT))
1010         TypeVals.push_back(true);
1011       break;
1012     }
1013     }
1014 
1015     // Emit the finished record.
1016     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
1017     TypeVals.clear();
1018   }
1019 
1020   Stream.ExitBlock();
1021 }
1022 
1023 static unsigned getEncodedLinkage(const GlobalValue::LinkageTypes Linkage) {
1024   switch (Linkage) {
1025   case GlobalValue::ExternalLinkage:
1026     return 0;
1027   case GlobalValue::WeakAnyLinkage:
1028     return 16;
1029   case GlobalValue::AppendingLinkage:
1030     return 2;
1031   case GlobalValue::InternalLinkage:
1032     return 3;
1033   case GlobalValue::LinkOnceAnyLinkage:
1034     return 18;
1035   case GlobalValue::ExternalWeakLinkage:
1036     return 7;
1037   case GlobalValue::CommonLinkage:
1038     return 8;
1039   case GlobalValue::PrivateLinkage:
1040     return 9;
1041   case GlobalValue::WeakODRLinkage:
1042     return 17;
1043   case GlobalValue::LinkOnceODRLinkage:
1044     return 19;
1045   case GlobalValue::AvailableExternallyLinkage:
1046     return 12;
1047   }
1048   llvm_unreachable("Invalid linkage");
1049 }
1050 
1051 static unsigned getEncodedLinkage(const GlobalValue &GV) {
1052   return getEncodedLinkage(GV.getLinkage());
1053 }
1054 
1055 static uint64_t getEncodedFFlags(FunctionSummary::FFlags Flags) {
1056   uint64_t RawFlags = 0;
1057   RawFlags |= Flags.ReadNone;
1058   RawFlags |= (Flags.ReadOnly << 1);
1059   RawFlags |= (Flags.NoRecurse << 2);
1060   RawFlags |= (Flags.ReturnDoesNotAlias << 3);
1061   RawFlags |= (Flags.NoInline << 4);
1062   RawFlags |= (Flags.AlwaysInline << 5);
1063   return RawFlags;
1064 }
1065 
1066 // Decode the flags for GlobalValue in the summary. See getDecodedGVSummaryFlags
1067 // in BitcodeReader.cpp.
1068 static uint64_t getEncodedGVSummaryFlags(GlobalValueSummary::GVFlags Flags) {
1069   uint64_t RawFlags = 0;
1070 
1071   RawFlags |= Flags.NotEligibleToImport; // bool
1072   RawFlags |= (Flags.Live << 1);
1073   RawFlags |= (Flags.DSOLocal << 2);
1074   RawFlags |= (Flags.CanAutoHide << 3);
1075 
1076   // Linkage don't need to be remapped at that time for the summary. Any future
1077   // change to the getEncodedLinkage() function will need to be taken into
1078   // account here as well.
1079   RawFlags = (RawFlags << 4) | Flags.Linkage; // 4 bits
1080 
1081   RawFlags |= (Flags.Visibility << 8); // 2 bits
1082 
1083   return RawFlags;
1084 }
1085 
1086 static uint64_t getEncodedGVarFlags(GlobalVarSummary::GVarFlags Flags) {
1087   uint64_t RawFlags = Flags.MaybeReadOnly | (Flags.MaybeWriteOnly << 1) |
1088                       (Flags.Constant << 2) | Flags.VCallVisibility << 3;
1089   return RawFlags;
1090 }
1091 
1092 static unsigned getEncodedVisibility(const GlobalValue &GV) {
1093   switch (GV.getVisibility()) {
1094   case GlobalValue::DefaultVisibility:   return 0;
1095   case GlobalValue::HiddenVisibility:    return 1;
1096   case GlobalValue::ProtectedVisibility: return 2;
1097   }
1098   llvm_unreachable("Invalid visibility");
1099 }
1100 
1101 static unsigned getEncodedDLLStorageClass(const GlobalValue &GV) {
1102   switch (GV.getDLLStorageClass()) {
1103   case GlobalValue::DefaultStorageClass:   return 0;
1104   case GlobalValue::DLLImportStorageClass: return 1;
1105   case GlobalValue::DLLExportStorageClass: return 2;
1106   }
1107   llvm_unreachable("Invalid DLL storage class");
1108 }
1109 
1110 static unsigned getEncodedThreadLocalMode(const GlobalValue &GV) {
1111   switch (GV.getThreadLocalMode()) {
1112     case GlobalVariable::NotThreadLocal:         return 0;
1113     case GlobalVariable::GeneralDynamicTLSModel: return 1;
1114     case GlobalVariable::LocalDynamicTLSModel:   return 2;
1115     case GlobalVariable::InitialExecTLSModel:    return 3;
1116     case GlobalVariable::LocalExecTLSModel:      return 4;
1117   }
1118   llvm_unreachable("Invalid TLS model");
1119 }
1120 
1121 static unsigned getEncodedComdatSelectionKind(const Comdat &C) {
1122   switch (C.getSelectionKind()) {
1123   case Comdat::Any:
1124     return bitc::COMDAT_SELECTION_KIND_ANY;
1125   case Comdat::ExactMatch:
1126     return bitc::COMDAT_SELECTION_KIND_EXACT_MATCH;
1127   case Comdat::Largest:
1128     return bitc::COMDAT_SELECTION_KIND_LARGEST;
1129   case Comdat::NoDuplicates:
1130     return bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES;
1131   case Comdat::SameSize:
1132     return bitc::COMDAT_SELECTION_KIND_SAME_SIZE;
1133   }
1134   llvm_unreachable("Invalid selection kind");
1135 }
1136 
1137 static unsigned getEncodedUnnamedAddr(const GlobalValue &GV) {
1138   switch (GV.getUnnamedAddr()) {
1139   case GlobalValue::UnnamedAddr::None:   return 0;
1140   case GlobalValue::UnnamedAddr::Local:  return 2;
1141   case GlobalValue::UnnamedAddr::Global: return 1;
1142   }
1143   llvm_unreachable("Invalid unnamed_addr");
1144 }
1145 
1146 size_t ModuleBitcodeWriter::addToStrtab(StringRef Str) {
1147   if (GenerateHash)
1148     Hasher.update(Str);
1149   return StrtabBuilder.add(Str);
1150 }
1151 
1152 void ModuleBitcodeWriter::writeComdats() {
1153   SmallVector<unsigned, 64> Vals;
1154   for (const Comdat *C : VE.getComdats()) {
1155     // COMDAT: [strtab offset, strtab size, selection_kind]
1156     Vals.push_back(addToStrtab(C->getName()));
1157     Vals.push_back(C->getName().size());
1158     Vals.push_back(getEncodedComdatSelectionKind(*C));
1159     Stream.EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
1160     Vals.clear();
1161   }
1162 }
1163 
1164 /// Write a record that will eventually hold the word offset of the
1165 /// module-level VST. For now the offset is 0, which will be backpatched
1166 /// after the real VST is written. Saves the bit offset to backpatch.
1167 void ModuleBitcodeWriter::writeValueSymbolTableForwardDecl() {
1168   // Write a placeholder value in for the offset of the real VST,
1169   // which is written after the function blocks so that it can include
1170   // the offset of each function. The placeholder offset will be
1171   // updated when the real VST is written.
1172   auto Abbv = std::make_shared<BitCodeAbbrev>();
1173   Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_VSTOFFSET));
1174   // Blocks are 32-bit aligned, so we can use a 32-bit word offset to
1175   // hold the real VST offset. Must use fixed instead of VBR as we don't
1176   // know how many VBR chunks to reserve ahead of time.
1177   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
1178   unsigned VSTOffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1179 
1180   // Emit the placeholder
1181   uint64_t Vals[] = {bitc::MODULE_CODE_VSTOFFSET, 0};
1182   Stream.EmitRecordWithAbbrev(VSTOffsetAbbrev, Vals);
1183 
1184   // Compute and save the bit offset to the placeholder, which will be
1185   // patched when the real VST is written. We can simply subtract the 32-bit
1186   // fixed size from the current bit number to get the location to backpatch.
1187   VSTOffsetPlaceholder = Stream.GetCurrentBitNo() - 32;
1188 }
1189 
1190 enum StringEncoding { SE_Char6, SE_Fixed7, SE_Fixed8 };
1191 
1192 /// Determine the encoding to use for the given string name and length.
1193 static StringEncoding getStringEncoding(StringRef Str) {
1194   bool isChar6 = true;
1195   for (char C : Str) {
1196     if (isChar6)
1197       isChar6 = BitCodeAbbrevOp::isChar6(C);
1198     if ((unsigned char)C & 128)
1199       // don't bother scanning the rest.
1200       return SE_Fixed8;
1201   }
1202   if (isChar6)
1203     return SE_Char6;
1204   return SE_Fixed7;
1205 }
1206 
1207 /// Emit top-level description of module, including target triple, inline asm,
1208 /// descriptors for global variables, and function prototype info.
1209 /// Returns the bit offset to backpatch with the location of the real VST.
1210 void ModuleBitcodeWriter::writeModuleInfo() {
1211   // Emit various pieces of data attached to a module.
1212   if (!M.getTargetTriple().empty())
1213     writeStringRecord(Stream, bitc::MODULE_CODE_TRIPLE, M.getTargetTriple(),
1214                       0 /*TODO*/);
1215   const std::string &DL = M.getDataLayoutStr();
1216   if (!DL.empty())
1217     writeStringRecord(Stream, bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/);
1218   if (!M.getModuleInlineAsm().empty())
1219     writeStringRecord(Stream, bitc::MODULE_CODE_ASM, M.getModuleInlineAsm(),
1220                       0 /*TODO*/);
1221 
1222   // Emit information about sections and GC, computing how many there are. Also
1223   // compute the maximum alignment value.
1224   std::map<std::string, unsigned> SectionMap;
1225   std::map<std::string, unsigned> GCMap;
1226   MaybeAlign MaxAlignment;
1227   unsigned MaxGlobalType = 0;
1228   const auto UpdateMaxAlignment = [&MaxAlignment](const MaybeAlign A) {
1229     if (A)
1230       MaxAlignment = !MaxAlignment ? *A : std::max(*MaxAlignment, *A);
1231   };
1232   for (const GlobalVariable &GV : M.globals()) {
1233     UpdateMaxAlignment(GV.getAlign());
1234     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getValueType()));
1235     if (GV.hasSection()) {
1236       // Give section names unique ID's.
1237       unsigned &Entry = SectionMap[std::string(GV.getSection())];
1238       if (!Entry) {
1239         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
1240                           0 /*TODO*/);
1241         Entry = SectionMap.size();
1242       }
1243     }
1244   }
1245   for (const Function &F : M) {
1246     UpdateMaxAlignment(F.getAlign());
1247     if (F.hasSection()) {
1248       // Give section names unique ID's.
1249       unsigned &Entry = SectionMap[std::string(F.getSection())];
1250       if (!Entry) {
1251         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
1252                           0 /*TODO*/);
1253         Entry = SectionMap.size();
1254       }
1255     }
1256     if (F.hasGC()) {
1257       // Same for GC names.
1258       unsigned &Entry = GCMap[F.getGC()];
1259       if (!Entry) {
1260         writeStringRecord(Stream, bitc::MODULE_CODE_GCNAME, F.getGC(),
1261                           0 /*TODO*/);
1262         Entry = GCMap.size();
1263       }
1264     }
1265   }
1266 
1267   // Emit abbrev for globals, now that we know # sections and max alignment.
1268   unsigned SimpleGVarAbbrev = 0;
1269   if (!M.global_empty()) {
1270     // Add an abbrev for common globals with no visibility or thread localness.
1271     auto Abbv = std::make_shared<BitCodeAbbrev>();
1272     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
1273     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1274     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1275     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1276                               Log2_32_Ceil(MaxGlobalType+1)));
1277     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddrSpace << 2
1278                                                            //| explicitType << 1
1279                                                            //| constant
1280     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Initializer.
1281     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // Linkage.
1282     if (!MaxAlignment)                                     // Alignment.
1283       Abbv->Add(BitCodeAbbrevOp(0));
1284     else {
1285       unsigned MaxEncAlignment = getEncodedAlign(MaxAlignment);
1286       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1287                                Log2_32_Ceil(MaxEncAlignment+1)));
1288     }
1289     if (SectionMap.empty())                                    // Section.
1290       Abbv->Add(BitCodeAbbrevOp(0));
1291     else
1292       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1293                                Log2_32_Ceil(SectionMap.size()+1)));
1294     // Don't bother emitting vis + thread local.
1295     SimpleGVarAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1296   }
1297 
1298   SmallVector<unsigned, 64> Vals;
1299   // Emit the module's source file name.
1300   {
1301     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
1302     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
1303     if (Bits == SE_Char6)
1304       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
1305     else if (Bits == SE_Fixed7)
1306       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
1307 
1308     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
1309     auto Abbv = std::make_shared<BitCodeAbbrev>();
1310     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
1311     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1312     Abbv->Add(AbbrevOpToUse);
1313     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1314 
1315     for (const auto P : M.getSourceFileName())
1316       Vals.push_back((unsigned char)P);
1317 
1318     // Emit the finished record.
1319     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
1320     Vals.clear();
1321   }
1322 
1323   // Emit the global variable information.
1324   for (const GlobalVariable &GV : M.globals()) {
1325     unsigned AbbrevToUse = 0;
1326 
1327     // GLOBALVAR: [strtab offset, strtab size, type, isconst, initid,
1328     //             linkage, alignment, section, visibility, threadlocal,
1329     //             unnamed_addr, externally_initialized, dllstorageclass,
1330     //             comdat, attributes, DSO_Local]
1331     Vals.push_back(addToStrtab(GV.getName()));
1332     Vals.push_back(GV.getName().size());
1333     Vals.push_back(VE.getTypeID(GV.getValueType()));
1334     Vals.push_back(GV.getType()->getAddressSpace() << 2 | 2 | GV.isConstant());
1335     Vals.push_back(GV.isDeclaration() ? 0 :
1336                    (VE.getValueID(GV.getInitializer()) + 1));
1337     Vals.push_back(getEncodedLinkage(GV));
1338     Vals.push_back(getEncodedAlign(GV.getAlign()));
1339     Vals.push_back(GV.hasSection() ? SectionMap[std::string(GV.getSection())]
1340                                    : 0);
1341     if (GV.isThreadLocal() ||
1342         GV.getVisibility() != GlobalValue::DefaultVisibility ||
1343         GV.getUnnamedAddr() != GlobalValue::UnnamedAddr::None ||
1344         GV.isExternallyInitialized() ||
1345         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
1346         GV.hasComdat() ||
1347         GV.hasAttributes() ||
1348         GV.isDSOLocal() ||
1349         GV.hasPartition()) {
1350       Vals.push_back(getEncodedVisibility(GV));
1351       Vals.push_back(getEncodedThreadLocalMode(GV));
1352       Vals.push_back(getEncodedUnnamedAddr(GV));
1353       Vals.push_back(GV.isExternallyInitialized());
1354       Vals.push_back(getEncodedDLLStorageClass(GV));
1355       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
1356 
1357       auto AL = GV.getAttributesAsList(AttributeList::FunctionIndex);
1358       Vals.push_back(VE.getAttributeListID(AL));
1359 
1360       Vals.push_back(GV.isDSOLocal());
1361       Vals.push_back(addToStrtab(GV.getPartition()));
1362       Vals.push_back(GV.getPartition().size());
1363     } else {
1364       AbbrevToUse = SimpleGVarAbbrev;
1365     }
1366 
1367     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
1368     Vals.clear();
1369   }
1370 
1371   // Emit the function proto information.
1372   for (const Function &F : M) {
1373     // FUNCTION:  [strtab offset, strtab size, type, callingconv, isproto,
1374     //             linkage, paramattrs, alignment, section, visibility, gc,
1375     //             unnamed_addr, prologuedata, dllstorageclass, comdat,
1376     //             prefixdata, personalityfn, DSO_Local, addrspace]
1377     Vals.push_back(addToStrtab(F.getName()));
1378     Vals.push_back(F.getName().size());
1379     Vals.push_back(VE.getTypeID(F.getFunctionType()));
1380     Vals.push_back(F.getCallingConv());
1381     Vals.push_back(F.isDeclaration());
1382     Vals.push_back(getEncodedLinkage(F));
1383     Vals.push_back(VE.getAttributeListID(F.getAttributes()));
1384     Vals.push_back(getEncodedAlign(F.getAlign()));
1385     Vals.push_back(F.hasSection() ? SectionMap[std::string(F.getSection())]
1386                                   : 0);
1387     Vals.push_back(getEncodedVisibility(F));
1388     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
1389     Vals.push_back(getEncodedUnnamedAddr(F));
1390     Vals.push_back(F.hasPrologueData() ? (VE.getValueID(F.getPrologueData()) + 1)
1391                                        : 0);
1392     Vals.push_back(getEncodedDLLStorageClass(F));
1393     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
1394     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
1395                                      : 0);
1396     Vals.push_back(
1397         F.hasPersonalityFn() ? (VE.getValueID(F.getPersonalityFn()) + 1) : 0);
1398 
1399     Vals.push_back(F.isDSOLocal());
1400     Vals.push_back(F.getAddressSpace());
1401     Vals.push_back(addToStrtab(F.getPartition()));
1402     Vals.push_back(F.getPartition().size());
1403 
1404     unsigned AbbrevToUse = 0;
1405     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
1406     Vals.clear();
1407   }
1408 
1409   // Emit the alias information.
1410   for (const GlobalAlias &A : M.aliases()) {
1411     // ALIAS: [strtab offset, strtab size, alias type, aliasee val#, linkage,
1412     //         visibility, dllstorageclass, threadlocal, unnamed_addr,
1413     //         DSO_Local]
1414     Vals.push_back(addToStrtab(A.getName()));
1415     Vals.push_back(A.getName().size());
1416     Vals.push_back(VE.getTypeID(A.getValueType()));
1417     Vals.push_back(A.getType()->getAddressSpace());
1418     Vals.push_back(VE.getValueID(A.getAliasee()));
1419     Vals.push_back(getEncodedLinkage(A));
1420     Vals.push_back(getEncodedVisibility(A));
1421     Vals.push_back(getEncodedDLLStorageClass(A));
1422     Vals.push_back(getEncodedThreadLocalMode(A));
1423     Vals.push_back(getEncodedUnnamedAddr(A));
1424     Vals.push_back(A.isDSOLocal());
1425     Vals.push_back(addToStrtab(A.getPartition()));
1426     Vals.push_back(A.getPartition().size());
1427 
1428     unsigned AbbrevToUse = 0;
1429     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
1430     Vals.clear();
1431   }
1432 
1433   // Emit the ifunc information.
1434   for (const GlobalIFunc &I : M.ifuncs()) {
1435     // IFUNC: [strtab offset, strtab size, ifunc type, address space, resolver
1436     //         val#, linkage, visibility, DSO_Local]
1437     Vals.push_back(addToStrtab(I.getName()));
1438     Vals.push_back(I.getName().size());
1439     Vals.push_back(VE.getTypeID(I.getValueType()));
1440     Vals.push_back(I.getType()->getAddressSpace());
1441     Vals.push_back(VE.getValueID(I.getResolver()));
1442     Vals.push_back(getEncodedLinkage(I));
1443     Vals.push_back(getEncodedVisibility(I));
1444     Vals.push_back(I.isDSOLocal());
1445     Vals.push_back(addToStrtab(I.getPartition()));
1446     Vals.push_back(I.getPartition().size());
1447     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
1448     Vals.clear();
1449   }
1450 
1451   writeValueSymbolTableForwardDecl();
1452 }
1453 
1454 static uint64_t getOptimizationFlags(const Value *V) {
1455   uint64_t Flags = 0;
1456 
1457   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
1458     if (OBO->hasNoSignedWrap())
1459       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
1460     if (OBO->hasNoUnsignedWrap())
1461       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
1462   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
1463     if (PEO->isExact())
1464       Flags |= 1 << bitc::PEO_EXACT;
1465   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
1466     if (FPMO->hasAllowReassoc())
1467       Flags |= bitc::AllowReassoc;
1468     if (FPMO->hasNoNaNs())
1469       Flags |= bitc::NoNaNs;
1470     if (FPMO->hasNoInfs())
1471       Flags |= bitc::NoInfs;
1472     if (FPMO->hasNoSignedZeros())
1473       Flags |= bitc::NoSignedZeros;
1474     if (FPMO->hasAllowReciprocal())
1475       Flags |= bitc::AllowReciprocal;
1476     if (FPMO->hasAllowContract())
1477       Flags |= bitc::AllowContract;
1478     if (FPMO->hasApproxFunc())
1479       Flags |= bitc::ApproxFunc;
1480   }
1481 
1482   return Flags;
1483 }
1484 
1485 void ModuleBitcodeWriter::writeValueAsMetadata(
1486     const ValueAsMetadata *MD, SmallVectorImpl<uint64_t> &Record) {
1487   // Mimic an MDNode with a value as one operand.
1488   Value *V = MD->getValue();
1489   Record.push_back(VE.getTypeID(V->getType()));
1490   Record.push_back(VE.getValueID(V));
1491   Stream.EmitRecord(bitc::METADATA_VALUE, Record, 0);
1492   Record.clear();
1493 }
1494 
1495 void ModuleBitcodeWriter::writeMDTuple(const MDTuple *N,
1496                                        SmallVectorImpl<uint64_t> &Record,
1497                                        unsigned Abbrev) {
1498   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
1499     Metadata *MD = N->getOperand(i);
1500     assert(!(MD && isa<LocalAsMetadata>(MD)) &&
1501            "Unexpected function-local metadata");
1502     Record.push_back(VE.getMetadataOrNullID(MD));
1503   }
1504   Stream.EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
1505                                     : bitc::METADATA_NODE,
1506                     Record, Abbrev);
1507   Record.clear();
1508 }
1509 
1510 unsigned ModuleBitcodeWriter::createDILocationAbbrev() {
1511   // Assume the column is usually under 128, and always output the inlined-at
1512   // location (it's never more expensive than building an array size 1).
1513   auto Abbv = std::make_shared<BitCodeAbbrev>();
1514   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
1515   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1516   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1517   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1518   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1519   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1520   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1521   return Stream.EmitAbbrev(std::move(Abbv));
1522 }
1523 
1524 void ModuleBitcodeWriter::writeDILocation(const DILocation *N,
1525                                           SmallVectorImpl<uint64_t> &Record,
1526                                           unsigned &Abbrev) {
1527   if (!Abbrev)
1528     Abbrev = createDILocationAbbrev();
1529 
1530   Record.push_back(N->isDistinct());
1531   Record.push_back(N->getLine());
1532   Record.push_back(N->getColumn());
1533   Record.push_back(VE.getMetadataID(N->getScope()));
1534   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
1535   Record.push_back(N->isImplicitCode());
1536 
1537   Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
1538   Record.clear();
1539 }
1540 
1541 unsigned ModuleBitcodeWriter::createGenericDINodeAbbrev() {
1542   // Assume the column is usually under 128, and always output the inlined-at
1543   // location (it's never more expensive than building an array size 1).
1544   auto Abbv = std::make_shared<BitCodeAbbrev>();
1545   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
1546   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1547   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1548   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1549   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1550   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1551   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1552   return Stream.EmitAbbrev(std::move(Abbv));
1553 }
1554 
1555 void ModuleBitcodeWriter::writeGenericDINode(const GenericDINode *N,
1556                                              SmallVectorImpl<uint64_t> &Record,
1557                                              unsigned &Abbrev) {
1558   if (!Abbrev)
1559     Abbrev = createGenericDINodeAbbrev();
1560 
1561   Record.push_back(N->isDistinct());
1562   Record.push_back(N->getTag());
1563   Record.push_back(0); // Per-tag version field; unused for now.
1564 
1565   for (auto &I : N->operands())
1566     Record.push_back(VE.getMetadataOrNullID(I));
1567 
1568   Stream.EmitRecord(bitc::METADATA_GENERIC_DEBUG, Record, Abbrev);
1569   Record.clear();
1570 }
1571 
1572 void ModuleBitcodeWriter::writeDISubrange(const DISubrange *N,
1573                                           SmallVectorImpl<uint64_t> &Record,
1574                                           unsigned Abbrev) {
1575   const uint64_t Version = 2 << 1;
1576   Record.push_back((uint64_t)N->isDistinct() | Version);
1577   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1578   Record.push_back(VE.getMetadataOrNullID(N->getRawLowerBound()));
1579   Record.push_back(VE.getMetadataOrNullID(N->getRawUpperBound()));
1580   Record.push_back(VE.getMetadataOrNullID(N->getRawStride()));
1581 
1582   Stream.EmitRecord(bitc::METADATA_SUBRANGE, Record, Abbrev);
1583   Record.clear();
1584 }
1585 
1586 void ModuleBitcodeWriter::writeDIGenericSubrange(
1587     const DIGenericSubrange *N, SmallVectorImpl<uint64_t> &Record,
1588     unsigned Abbrev) {
1589   Record.push_back((uint64_t)N->isDistinct());
1590   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1591   Record.push_back(VE.getMetadataOrNullID(N->getRawLowerBound()));
1592   Record.push_back(VE.getMetadataOrNullID(N->getRawUpperBound()));
1593   Record.push_back(VE.getMetadataOrNullID(N->getRawStride()));
1594 
1595   Stream.EmitRecord(bitc::METADATA_GENERIC_SUBRANGE, Record, Abbrev);
1596   Record.clear();
1597 }
1598 
1599 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
1600   if ((int64_t)V >= 0)
1601     Vals.push_back(V << 1);
1602   else
1603     Vals.push_back((-V << 1) | 1);
1604 }
1605 
1606 static void emitWideAPInt(SmallVectorImpl<uint64_t> &Vals, const APInt &A) {
1607   // We have an arbitrary precision integer value to write whose
1608   // bit width is > 64. However, in canonical unsigned integer
1609   // format it is likely that the high bits are going to be zero.
1610   // So, we only write the number of active words.
1611   unsigned NumWords = A.getActiveWords();
1612   const uint64_t *RawData = A.getRawData();
1613   for (unsigned i = 0; i < NumWords; i++)
1614     emitSignedInt64(Vals, RawData[i]);
1615 }
1616 
1617 void ModuleBitcodeWriter::writeDIEnumerator(const DIEnumerator *N,
1618                                             SmallVectorImpl<uint64_t> &Record,
1619                                             unsigned Abbrev) {
1620   const uint64_t IsBigInt = 1 << 2;
1621   Record.push_back(IsBigInt | (N->isUnsigned() << 1) | N->isDistinct());
1622   Record.push_back(N->getValue().getBitWidth());
1623   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1624   emitWideAPInt(Record, N->getValue());
1625 
1626   Stream.EmitRecord(bitc::METADATA_ENUMERATOR, Record, Abbrev);
1627   Record.clear();
1628 }
1629 
1630 void ModuleBitcodeWriter::writeDIBasicType(const DIBasicType *N,
1631                                            SmallVectorImpl<uint64_t> &Record,
1632                                            unsigned Abbrev) {
1633   Record.push_back(N->isDistinct());
1634   Record.push_back(N->getTag());
1635   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1636   Record.push_back(N->getSizeInBits());
1637   Record.push_back(N->getAlignInBits());
1638   Record.push_back(N->getEncoding());
1639   Record.push_back(N->getFlags());
1640 
1641   Stream.EmitRecord(bitc::METADATA_BASIC_TYPE, Record, Abbrev);
1642   Record.clear();
1643 }
1644 
1645 void ModuleBitcodeWriter::writeDIStringType(const DIStringType *N,
1646                                             SmallVectorImpl<uint64_t> &Record,
1647                                             unsigned Abbrev) {
1648   Record.push_back(N->isDistinct());
1649   Record.push_back(N->getTag());
1650   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1651   Record.push_back(VE.getMetadataOrNullID(N->getStringLength()));
1652   Record.push_back(VE.getMetadataOrNullID(N->getStringLengthExp()));
1653   Record.push_back(N->getSizeInBits());
1654   Record.push_back(N->getAlignInBits());
1655   Record.push_back(N->getEncoding());
1656 
1657   Stream.EmitRecord(bitc::METADATA_STRING_TYPE, Record, Abbrev);
1658   Record.clear();
1659 }
1660 
1661 void ModuleBitcodeWriter::writeDIDerivedType(const DIDerivedType *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->getFile()));
1668   Record.push_back(N->getLine());
1669   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1670   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1671   Record.push_back(N->getSizeInBits());
1672   Record.push_back(N->getAlignInBits());
1673   Record.push_back(N->getOffsetInBits());
1674   Record.push_back(N->getFlags());
1675   Record.push_back(VE.getMetadataOrNullID(N->getExtraData()));
1676 
1677   // DWARF address space is encoded as N->getDWARFAddressSpace() + 1. 0 means
1678   // that there is no DWARF address space associated with DIDerivedType.
1679   if (const auto &DWARFAddressSpace = N->getDWARFAddressSpace())
1680     Record.push_back(*DWARFAddressSpace + 1);
1681   else
1682     Record.push_back(0);
1683 
1684   Stream.EmitRecord(bitc::METADATA_DERIVED_TYPE, Record, Abbrev);
1685   Record.clear();
1686 }
1687 
1688 void ModuleBitcodeWriter::writeDICompositeType(
1689     const DICompositeType *N, SmallVectorImpl<uint64_t> &Record,
1690     unsigned Abbrev) {
1691   const unsigned IsNotUsedInOldTypeRef = 0x2;
1692   Record.push_back(IsNotUsedInOldTypeRef | (unsigned)N->isDistinct());
1693   Record.push_back(N->getTag());
1694   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1695   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1696   Record.push_back(N->getLine());
1697   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1698   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1699   Record.push_back(N->getSizeInBits());
1700   Record.push_back(N->getAlignInBits());
1701   Record.push_back(N->getOffsetInBits());
1702   Record.push_back(N->getFlags());
1703   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1704   Record.push_back(N->getRuntimeLang());
1705   Record.push_back(VE.getMetadataOrNullID(N->getVTableHolder()));
1706   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1707   Record.push_back(VE.getMetadataOrNullID(N->getRawIdentifier()));
1708   Record.push_back(VE.getMetadataOrNullID(N->getDiscriminator()));
1709   Record.push_back(VE.getMetadataOrNullID(N->getRawDataLocation()));
1710   Record.push_back(VE.getMetadataOrNullID(N->getRawAssociated()));
1711   Record.push_back(VE.getMetadataOrNullID(N->getRawAllocated()));
1712   Record.push_back(VE.getMetadataOrNullID(N->getRawRank()));
1713 
1714   Stream.EmitRecord(bitc::METADATA_COMPOSITE_TYPE, Record, Abbrev);
1715   Record.clear();
1716 }
1717 
1718 void ModuleBitcodeWriter::writeDISubroutineType(
1719     const DISubroutineType *N, SmallVectorImpl<uint64_t> &Record,
1720     unsigned Abbrev) {
1721   const unsigned HasNoOldTypeRefs = 0x2;
1722   Record.push_back(HasNoOldTypeRefs | (unsigned)N->isDistinct());
1723   Record.push_back(N->getFlags());
1724   Record.push_back(VE.getMetadataOrNullID(N->getTypeArray().get()));
1725   Record.push_back(N->getCC());
1726 
1727   Stream.EmitRecord(bitc::METADATA_SUBROUTINE_TYPE, Record, Abbrev);
1728   Record.clear();
1729 }
1730 
1731 void ModuleBitcodeWriter::writeDIFile(const DIFile *N,
1732                                       SmallVectorImpl<uint64_t> &Record,
1733                                       unsigned Abbrev) {
1734   Record.push_back(N->isDistinct());
1735   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
1736   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
1737   if (N->getRawChecksum()) {
1738     Record.push_back(N->getRawChecksum()->Kind);
1739     Record.push_back(VE.getMetadataOrNullID(N->getRawChecksum()->Value));
1740   } else {
1741     // Maintain backwards compatibility with the old internal representation of
1742     // CSK_None in ChecksumKind by writing nulls here when Checksum is None.
1743     Record.push_back(0);
1744     Record.push_back(VE.getMetadataOrNullID(nullptr));
1745   }
1746   auto Source = N->getRawSource();
1747   if (Source)
1748     Record.push_back(VE.getMetadataOrNullID(*Source));
1749 
1750   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
1751   Record.clear();
1752 }
1753 
1754 void ModuleBitcodeWriter::writeDICompileUnit(const DICompileUnit *N,
1755                                              SmallVectorImpl<uint64_t> &Record,
1756                                              unsigned Abbrev) {
1757   assert(N->isDistinct() && "Expected distinct compile units");
1758   Record.push_back(/* IsDistinct */ true);
1759   Record.push_back(N->getSourceLanguage());
1760   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1761   Record.push_back(VE.getMetadataOrNullID(N->getRawProducer()));
1762   Record.push_back(N->isOptimized());
1763   Record.push_back(VE.getMetadataOrNullID(N->getRawFlags()));
1764   Record.push_back(N->getRuntimeVersion());
1765   Record.push_back(VE.getMetadataOrNullID(N->getRawSplitDebugFilename()));
1766   Record.push_back(N->getEmissionKind());
1767   Record.push_back(VE.getMetadataOrNullID(N->getEnumTypes().get()));
1768   Record.push_back(VE.getMetadataOrNullID(N->getRetainedTypes().get()));
1769   Record.push_back(/* subprograms */ 0);
1770   Record.push_back(VE.getMetadataOrNullID(N->getGlobalVariables().get()));
1771   Record.push_back(VE.getMetadataOrNullID(N->getImportedEntities().get()));
1772   Record.push_back(N->getDWOId());
1773   Record.push_back(VE.getMetadataOrNullID(N->getMacros().get()));
1774   Record.push_back(N->getSplitDebugInlining());
1775   Record.push_back(N->getDebugInfoForProfiling());
1776   Record.push_back((unsigned)N->getNameTableKind());
1777   Record.push_back(N->getRangesBaseAddress());
1778   Record.push_back(VE.getMetadataOrNullID(N->getRawSysRoot()));
1779   Record.push_back(VE.getMetadataOrNullID(N->getRawSDK()));
1780 
1781   Stream.EmitRecord(bitc::METADATA_COMPILE_UNIT, Record, Abbrev);
1782   Record.clear();
1783 }
1784 
1785 void ModuleBitcodeWriter::writeDISubprogram(const DISubprogram *N,
1786                                             SmallVectorImpl<uint64_t> &Record,
1787                                             unsigned Abbrev) {
1788   const uint64_t HasUnitFlag = 1 << 1;
1789   const uint64_t HasSPFlagsFlag = 1 << 2;
1790   Record.push_back(uint64_t(N->isDistinct()) | HasUnitFlag | HasSPFlagsFlag);
1791   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1792   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1793   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1794   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1795   Record.push_back(N->getLine());
1796   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1797   Record.push_back(N->getScopeLine());
1798   Record.push_back(VE.getMetadataOrNullID(N->getContainingType()));
1799   Record.push_back(N->getSPFlags());
1800   Record.push_back(N->getVirtualIndex());
1801   Record.push_back(N->getFlags());
1802   Record.push_back(VE.getMetadataOrNullID(N->getRawUnit()));
1803   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1804   Record.push_back(VE.getMetadataOrNullID(N->getDeclaration()));
1805   Record.push_back(VE.getMetadataOrNullID(N->getRetainedNodes().get()));
1806   Record.push_back(N->getThisAdjustment());
1807   Record.push_back(VE.getMetadataOrNullID(N->getThrownTypes().get()));
1808 
1809   Stream.EmitRecord(bitc::METADATA_SUBPROGRAM, Record, Abbrev);
1810   Record.clear();
1811 }
1812 
1813 void ModuleBitcodeWriter::writeDILexicalBlock(const DILexicalBlock *N,
1814                                               SmallVectorImpl<uint64_t> &Record,
1815                                               unsigned Abbrev) {
1816   Record.push_back(N->isDistinct());
1817   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1818   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1819   Record.push_back(N->getLine());
1820   Record.push_back(N->getColumn());
1821 
1822   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK, Record, Abbrev);
1823   Record.clear();
1824 }
1825 
1826 void ModuleBitcodeWriter::writeDILexicalBlockFile(
1827     const DILexicalBlockFile *N, SmallVectorImpl<uint64_t> &Record,
1828     unsigned Abbrev) {
1829   Record.push_back(N->isDistinct());
1830   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1831   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1832   Record.push_back(N->getDiscriminator());
1833 
1834   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK_FILE, Record, Abbrev);
1835   Record.clear();
1836 }
1837 
1838 void ModuleBitcodeWriter::writeDICommonBlock(const DICommonBlock *N,
1839                                              SmallVectorImpl<uint64_t> &Record,
1840                                              unsigned Abbrev) {
1841   Record.push_back(N->isDistinct());
1842   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1843   Record.push_back(VE.getMetadataOrNullID(N->getDecl()));
1844   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1845   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1846   Record.push_back(N->getLineNo());
1847 
1848   Stream.EmitRecord(bitc::METADATA_COMMON_BLOCK, Record, Abbrev);
1849   Record.clear();
1850 }
1851 
1852 void ModuleBitcodeWriter::writeDINamespace(const DINamespace *N,
1853                                            SmallVectorImpl<uint64_t> &Record,
1854                                            unsigned Abbrev) {
1855   Record.push_back(N->isDistinct() | N->getExportSymbols() << 1);
1856   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1857   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1858 
1859   Stream.EmitRecord(bitc::METADATA_NAMESPACE, Record, Abbrev);
1860   Record.clear();
1861 }
1862 
1863 void ModuleBitcodeWriter::writeDIMacro(const DIMacro *N,
1864                                        SmallVectorImpl<uint64_t> &Record,
1865                                        unsigned Abbrev) {
1866   Record.push_back(N->isDistinct());
1867   Record.push_back(N->getMacinfoType());
1868   Record.push_back(N->getLine());
1869   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1870   Record.push_back(VE.getMetadataOrNullID(N->getRawValue()));
1871 
1872   Stream.EmitRecord(bitc::METADATA_MACRO, Record, Abbrev);
1873   Record.clear();
1874 }
1875 
1876 void ModuleBitcodeWriter::writeDIMacroFile(const DIMacroFile *N,
1877                                            SmallVectorImpl<uint64_t> &Record,
1878                                            unsigned Abbrev) {
1879   Record.push_back(N->isDistinct());
1880   Record.push_back(N->getMacinfoType());
1881   Record.push_back(N->getLine());
1882   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1883   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1884 
1885   Stream.EmitRecord(bitc::METADATA_MACRO_FILE, Record, Abbrev);
1886   Record.clear();
1887 }
1888 
1889 void ModuleBitcodeWriter::writeDIArgList(const DIArgList *N,
1890                                          SmallVectorImpl<uint64_t> &Record,
1891                                          unsigned Abbrev) {
1892   Record.reserve(N->getArgs().size());
1893   for (ValueAsMetadata *MD : N->getArgs())
1894     Record.push_back(VE.getMetadataID(MD));
1895 
1896   Stream.EmitRecord(bitc::METADATA_ARG_LIST, Record, Abbrev);
1897   Record.clear();
1898 }
1899 
1900 void ModuleBitcodeWriter::writeDIModule(const DIModule *N,
1901                                         SmallVectorImpl<uint64_t> &Record,
1902                                         unsigned Abbrev) {
1903   Record.push_back(N->isDistinct());
1904   for (auto &I : N->operands())
1905     Record.push_back(VE.getMetadataOrNullID(I));
1906   Record.push_back(N->getLineNo());
1907   Record.push_back(N->getIsDecl());
1908 
1909   Stream.EmitRecord(bitc::METADATA_MODULE, Record, Abbrev);
1910   Record.clear();
1911 }
1912 
1913 void ModuleBitcodeWriter::writeDITemplateTypeParameter(
1914     const DITemplateTypeParameter *N, SmallVectorImpl<uint64_t> &Record,
1915     unsigned Abbrev) {
1916   Record.push_back(N->isDistinct());
1917   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1918   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1919   Record.push_back(N->isDefault());
1920 
1921   Stream.EmitRecord(bitc::METADATA_TEMPLATE_TYPE, Record, Abbrev);
1922   Record.clear();
1923 }
1924 
1925 void ModuleBitcodeWriter::writeDITemplateValueParameter(
1926     const DITemplateValueParameter *N, SmallVectorImpl<uint64_t> &Record,
1927     unsigned Abbrev) {
1928   Record.push_back(N->isDistinct());
1929   Record.push_back(N->getTag());
1930   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1931   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1932   Record.push_back(N->isDefault());
1933   Record.push_back(VE.getMetadataOrNullID(N->getValue()));
1934 
1935   Stream.EmitRecord(bitc::METADATA_TEMPLATE_VALUE, Record, Abbrev);
1936   Record.clear();
1937 }
1938 
1939 void ModuleBitcodeWriter::writeDIGlobalVariable(
1940     const DIGlobalVariable *N, SmallVectorImpl<uint64_t> &Record,
1941     unsigned Abbrev) {
1942   const uint64_t Version = 2 << 1;
1943   Record.push_back((uint64_t)N->isDistinct() | Version);
1944   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1945   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1946   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1947   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1948   Record.push_back(N->getLine());
1949   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1950   Record.push_back(N->isLocalToUnit());
1951   Record.push_back(N->isDefinition());
1952   Record.push_back(VE.getMetadataOrNullID(N->getStaticDataMemberDeclaration()));
1953   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams()));
1954   Record.push_back(N->getAlignInBits());
1955 
1956   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR, Record, Abbrev);
1957   Record.clear();
1958 }
1959 
1960 void ModuleBitcodeWriter::writeDILocalVariable(
1961     const DILocalVariable *N, SmallVectorImpl<uint64_t> &Record,
1962     unsigned Abbrev) {
1963   // In order to support all possible bitcode formats in BitcodeReader we need
1964   // to distinguish the following cases:
1965   // 1) Record has no artificial tag (Record[1]),
1966   //   has no obsolete inlinedAt field (Record[9]).
1967   //   In this case Record size will be 8, HasAlignment flag is false.
1968   // 2) Record has artificial tag (Record[1]),
1969   //   has no obsolete inlignedAt field (Record[9]).
1970   //   In this case Record size will be 9, HasAlignment flag is false.
1971   // 3) Record has both artificial tag (Record[1]) and
1972   //   obsolete inlignedAt field (Record[9]).
1973   //   In this case Record size will be 10, HasAlignment flag is false.
1974   // 4) Record has neither artificial tag, nor inlignedAt field, but
1975   //   HasAlignment flag is true and Record[8] contains alignment value.
1976   const uint64_t HasAlignmentFlag = 1 << 1;
1977   Record.push_back((uint64_t)N->isDistinct() | HasAlignmentFlag);
1978   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1979   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1980   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1981   Record.push_back(N->getLine());
1982   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1983   Record.push_back(N->getArg());
1984   Record.push_back(N->getFlags());
1985   Record.push_back(N->getAlignInBits());
1986 
1987   Stream.EmitRecord(bitc::METADATA_LOCAL_VAR, Record, Abbrev);
1988   Record.clear();
1989 }
1990 
1991 void ModuleBitcodeWriter::writeDILabel(
1992     const DILabel *N, SmallVectorImpl<uint64_t> &Record,
1993     unsigned Abbrev) {
1994   Record.push_back((uint64_t)N->isDistinct());
1995   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1996   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1997   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1998   Record.push_back(N->getLine());
1999 
2000   Stream.EmitRecord(bitc::METADATA_LABEL, Record, Abbrev);
2001   Record.clear();
2002 }
2003 
2004 void ModuleBitcodeWriter::writeDIExpression(const DIExpression *N,
2005                                             SmallVectorImpl<uint64_t> &Record,
2006                                             unsigned Abbrev) {
2007   Record.reserve(N->getElements().size() + 1);
2008   const uint64_t Version = 3 << 1;
2009   Record.push_back((uint64_t)N->isDistinct() | Version);
2010   Record.append(N->elements_begin(), N->elements_end());
2011 
2012   Stream.EmitRecord(bitc::METADATA_EXPRESSION, Record, Abbrev);
2013   Record.clear();
2014 }
2015 
2016 void ModuleBitcodeWriter::writeDIGlobalVariableExpression(
2017     const DIGlobalVariableExpression *N, SmallVectorImpl<uint64_t> &Record,
2018     unsigned Abbrev) {
2019   Record.push_back(N->isDistinct());
2020   Record.push_back(VE.getMetadataOrNullID(N->getVariable()));
2021   Record.push_back(VE.getMetadataOrNullID(N->getExpression()));
2022 
2023   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR_EXPR, Record, Abbrev);
2024   Record.clear();
2025 }
2026 
2027 void ModuleBitcodeWriter::writeDIObjCProperty(const DIObjCProperty *N,
2028                                               SmallVectorImpl<uint64_t> &Record,
2029                                               unsigned Abbrev) {
2030   Record.push_back(N->isDistinct());
2031   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2032   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2033   Record.push_back(N->getLine());
2034   Record.push_back(VE.getMetadataOrNullID(N->getRawSetterName()));
2035   Record.push_back(VE.getMetadataOrNullID(N->getRawGetterName()));
2036   Record.push_back(N->getAttributes());
2037   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2038 
2039   Stream.EmitRecord(bitc::METADATA_OBJC_PROPERTY, Record, Abbrev);
2040   Record.clear();
2041 }
2042 
2043 void ModuleBitcodeWriter::writeDIImportedEntity(
2044     const DIImportedEntity *N, SmallVectorImpl<uint64_t> &Record,
2045     unsigned Abbrev) {
2046   Record.push_back(N->isDistinct());
2047   Record.push_back(N->getTag());
2048   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2049   Record.push_back(VE.getMetadataOrNullID(N->getEntity()));
2050   Record.push_back(N->getLine());
2051   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2052   Record.push_back(VE.getMetadataOrNullID(N->getRawFile()));
2053 
2054   Stream.EmitRecord(bitc::METADATA_IMPORTED_ENTITY, Record, Abbrev);
2055   Record.clear();
2056 }
2057 
2058 unsigned ModuleBitcodeWriter::createNamedMetadataAbbrev() {
2059   auto Abbv = std::make_shared<BitCodeAbbrev>();
2060   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
2061   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2062   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2063   return Stream.EmitAbbrev(std::move(Abbv));
2064 }
2065 
2066 void ModuleBitcodeWriter::writeNamedMetadata(
2067     SmallVectorImpl<uint64_t> &Record) {
2068   if (M.named_metadata_empty())
2069     return;
2070 
2071   unsigned Abbrev = createNamedMetadataAbbrev();
2072   for (const NamedMDNode &NMD : M.named_metadata()) {
2073     // Write name.
2074     StringRef Str = NMD.getName();
2075     Record.append(Str.bytes_begin(), Str.bytes_end());
2076     Stream.EmitRecord(bitc::METADATA_NAME, Record, Abbrev);
2077     Record.clear();
2078 
2079     // Write named metadata operands.
2080     for (const MDNode *N : NMD.operands())
2081       Record.push_back(VE.getMetadataID(N));
2082     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
2083     Record.clear();
2084   }
2085 }
2086 
2087 unsigned ModuleBitcodeWriter::createMetadataStringsAbbrev() {
2088   auto Abbv = std::make_shared<BitCodeAbbrev>();
2089   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRINGS));
2090   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // # of strings
2091   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // offset to chars
2092   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
2093   return Stream.EmitAbbrev(std::move(Abbv));
2094 }
2095 
2096 /// Write out a record for MDString.
2097 ///
2098 /// All the metadata strings in a metadata block are emitted in a single
2099 /// record.  The sizes and strings themselves are shoved into a blob.
2100 void ModuleBitcodeWriter::writeMetadataStrings(
2101     ArrayRef<const Metadata *> Strings, SmallVectorImpl<uint64_t> &Record) {
2102   if (Strings.empty())
2103     return;
2104 
2105   // Start the record with the number of strings.
2106   Record.push_back(bitc::METADATA_STRINGS);
2107   Record.push_back(Strings.size());
2108 
2109   // Emit the sizes of the strings in the blob.
2110   SmallString<256> Blob;
2111   {
2112     BitstreamWriter W(Blob);
2113     for (const Metadata *MD : Strings)
2114       W.EmitVBR(cast<MDString>(MD)->getLength(), 6);
2115     W.FlushToWord();
2116   }
2117 
2118   // Add the offset to the strings to the record.
2119   Record.push_back(Blob.size());
2120 
2121   // Add the strings to the blob.
2122   for (const Metadata *MD : Strings)
2123     Blob.append(cast<MDString>(MD)->getString());
2124 
2125   // Emit the final record.
2126   Stream.EmitRecordWithBlob(createMetadataStringsAbbrev(), Record, Blob);
2127   Record.clear();
2128 }
2129 
2130 // Generates an enum to use as an index in the Abbrev array of Metadata record.
2131 enum MetadataAbbrev : unsigned {
2132 #define HANDLE_MDNODE_LEAF(CLASS) CLASS##AbbrevID,
2133 #include "llvm/IR/Metadata.def"
2134   LastPlusOne
2135 };
2136 
2137 void ModuleBitcodeWriter::writeMetadataRecords(
2138     ArrayRef<const Metadata *> MDs, SmallVectorImpl<uint64_t> &Record,
2139     std::vector<unsigned> *MDAbbrevs, std::vector<uint64_t> *IndexPos) {
2140   if (MDs.empty())
2141     return;
2142 
2143   // Initialize MDNode abbreviations.
2144 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
2145 #include "llvm/IR/Metadata.def"
2146 
2147   for (const Metadata *MD : MDs) {
2148     if (IndexPos)
2149       IndexPos->push_back(Stream.GetCurrentBitNo());
2150     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
2151       assert(N->isResolved() && "Expected forward references to be resolved");
2152 
2153       switch (N->getMetadataID()) {
2154       default:
2155         llvm_unreachable("Invalid MDNode subclass");
2156 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
2157   case Metadata::CLASS##Kind:                                                  \
2158     if (MDAbbrevs)                                                             \
2159       write##CLASS(cast<CLASS>(N), Record,                                     \
2160                    (*MDAbbrevs)[MetadataAbbrev::CLASS##AbbrevID]);             \
2161     else                                                                       \
2162       write##CLASS(cast<CLASS>(N), Record, CLASS##Abbrev);                     \
2163     continue;
2164 #include "llvm/IR/Metadata.def"
2165       }
2166     }
2167     writeValueAsMetadata(cast<ValueAsMetadata>(MD), Record);
2168   }
2169 }
2170 
2171 void ModuleBitcodeWriter::writeModuleMetadata() {
2172   if (!VE.hasMDs() && M.named_metadata_empty())
2173     return;
2174 
2175   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 4);
2176   SmallVector<uint64_t, 64> Record;
2177 
2178   // Emit all abbrevs upfront, so that the reader can jump in the middle of the
2179   // block and load any metadata.
2180   std::vector<unsigned> MDAbbrevs;
2181 
2182   MDAbbrevs.resize(MetadataAbbrev::LastPlusOne);
2183   MDAbbrevs[MetadataAbbrev::DILocationAbbrevID] = createDILocationAbbrev();
2184   MDAbbrevs[MetadataAbbrev::GenericDINodeAbbrevID] =
2185       createGenericDINodeAbbrev();
2186 
2187   auto Abbv = std::make_shared<BitCodeAbbrev>();
2188   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX_OFFSET));
2189   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2190   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2191   unsigned OffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2192 
2193   Abbv = std::make_shared<BitCodeAbbrev>();
2194   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX));
2195   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2196   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2197   unsigned IndexAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2198 
2199   // Emit MDStrings together upfront.
2200   writeMetadataStrings(VE.getMDStrings(), Record);
2201 
2202   // We only emit an index for the metadata record if we have more than a given
2203   // (naive) threshold of metadatas, otherwise it is not worth it.
2204   if (VE.getNonMDStrings().size() > IndexThreshold) {
2205     // Write a placeholder value in for the offset of the metadata index,
2206     // which is written after the records, so that it can include
2207     // the offset of each entry. The placeholder offset will be
2208     // updated after all records are emitted.
2209     uint64_t Vals[] = {0, 0};
2210     Stream.EmitRecord(bitc::METADATA_INDEX_OFFSET, Vals, OffsetAbbrev);
2211   }
2212 
2213   // Compute and save the bit offset to the current position, which will be
2214   // patched when we emit the index later. We can simply subtract the 64-bit
2215   // fixed size from the current bit number to get the location to backpatch.
2216   uint64_t IndexOffsetRecordBitPos = Stream.GetCurrentBitNo();
2217 
2218   // This index will contain the bitpos for each individual record.
2219   std::vector<uint64_t> IndexPos;
2220   IndexPos.reserve(VE.getNonMDStrings().size());
2221 
2222   // Write all the records
2223   writeMetadataRecords(VE.getNonMDStrings(), Record, &MDAbbrevs, &IndexPos);
2224 
2225   if (VE.getNonMDStrings().size() > IndexThreshold) {
2226     // Now that we have emitted all the records we will emit the index. But
2227     // first
2228     // backpatch the forward reference so that the reader can skip the records
2229     // efficiently.
2230     Stream.BackpatchWord64(IndexOffsetRecordBitPos - 64,
2231                            Stream.GetCurrentBitNo() - IndexOffsetRecordBitPos);
2232 
2233     // Delta encode the index.
2234     uint64_t PreviousValue = IndexOffsetRecordBitPos;
2235     for (auto &Elt : IndexPos) {
2236       auto EltDelta = Elt - PreviousValue;
2237       PreviousValue = Elt;
2238       Elt = EltDelta;
2239     }
2240     // Emit the index record.
2241     Stream.EmitRecord(bitc::METADATA_INDEX, IndexPos, IndexAbbrev);
2242     IndexPos.clear();
2243   }
2244 
2245   // Write the named metadata now.
2246   writeNamedMetadata(Record);
2247 
2248   auto AddDeclAttachedMetadata = [&](const GlobalObject &GO) {
2249     SmallVector<uint64_t, 4> Record;
2250     Record.push_back(VE.getValueID(&GO));
2251     pushGlobalMetadataAttachment(Record, GO);
2252     Stream.EmitRecord(bitc::METADATA_GLOBAL_DECL_ATTACHMENT, Record);
2253   };
2254   for (const Function &F : M)
2255     if (F.isDeclaration() && F.hasMetadata())
2256       AddDeclAttachedMetadata(F);
2257   // FIXME: Only store metadata for declarations here, and move data for global
2258   // variable definitions to a separate block (PR28134).
2259   for (const GlobalVariable &GV : M.globals())
2260     if (GV.hasMetadata())
2261       AddDeclAttachedMetadata(GV);
2262 
2263   Stream.ExitBlock();
2264 }
2265 
2266 void ModuleBitcodeWriter::writeFunctionMetadata(const Function &F) {
2267   if (!VE.hasMDs())
2268     return;
2269 
2270   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
2271   SmallVector<uint64_t, 64> Record;
2272   writeMetadataStrings(VE.getMDStrings(), Record);
2273   writeMetadataRecords(VE.getNonMDStrings(), Record);
2274   Stream.ExitBlock();
2275 }
2276 
2277 void ModuleBitcodeWriter::pushGlobalMetadataAttachment(
2278     SmallVectorImpl<uint64_t> &Record, const GlobalObject &GO) {
2279   // [n x [id, mdnode]]
2280   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2281   GO.getAllMetadata(MDs);
2282   for (const auto &I : MDs) {
2283     Record.push_back(I.first);
2284     Record.push_back(VE.getMetadataID(I.second));
2285   }
2286 }
2287 
2288 void ModuleBitcodeWriter::writeFunctionMetadataAttachment(const Function &F) {
2289   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
2290 
2291   SmallVector<uint64_t, 64> Record;
2292 
2293   if (F.hasMetadata()) {
2294     pushGlobalMetadataAttachment(Record, F);
2295     Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2296     Record.clear();
2297   }
2298 
2299   // Write metadata attachments
2300   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
2301   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2302   for (const BasicBlock &BB : F)
2303     for (const Instruction &I : BB) {
2304       MDs.clear();
2305       I.getAllMetadataOtherThanDebugLoc(MDs);
2306 
2307       // If no metadata, ignore instruction.
2308       if (MDs.empty()) continue;
2309 
2310       Record.push_back(VE.getInstructionID(&I));
2311 
2312       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
2313         Record.push_back(MDs[i].first);
2314         Record.push_back(VE.getMetadataID(MDs[i].second));
2315       }
2316       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2317       Record.clear();
2318     }
2319 
2320   Stream.ExitBlock();
2321 }
2322 
2323 void ModuleBitcodeWriter::writeModuleMetadataKinds() {
2324   SmallVector<uint64_t, 64> Record;
2325 
2326   // Write metadata kinds
2327   // METADATA_KIND - [n x [id, name]]
2328   SmallVector<StringRef, 8> Names;
2329   M.getMDKindNames(Names);
2330 
2331   if (Names.empty()) return;
2332 
2333   Stream.EnterSubblock(bitc::METADATA_KIND_BLOCK_ID, 3);
2334 
2335   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
2336     Record.push_back(MDKindID);
2337     StringRef KName = Names[MDKindID];
2338     Record.append(KName.begin(), KName.end());
2339 
2340     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
2341     Record.clear();
2342   }
2343 
2344   Stream.ExitBlock();
2345 }
2346 
2347 void ModuleBitcodeWriter::writeOperandBundleTags() {
2348   // Write metadata kinds
2349   //
2350   // OPERAND_BUNDLE_TAGS_BLOCK_ID : N x OPERAND_BUNDLE_TAG
2351   //
2352   // OPERAND_BUNDLE_TAG - [strchr x N]
2353 
2354   SmallVector<StringRef, 8> Tags;
2355   M.getOperandBundleTags(Tags);
2356 
2357   if (Tags.empty())
2358     return;
2359 
2360   Stream.EnterSubblock(bitc::OPERAND_BUNDLE_TAGS_BLOCK_ID, 3);
2361 
2362   SmallVector<uint64_t, 64> Record;
2363 
2364   for (auto Tag : Tags) {
2365     Record.append(Tag.begin(), Tag.end());
2366 
2367     Stream.EmitRecord(bitc::OPERAND_BUNDLE_TAG, Record, 0);
2368     Record.clear();
2369   }
2370 
2371   Stream.ExitBlock();
2372 }
2373 
2374 void ModuleBitcodeWriter::writeSyncScopeNames() {
2375   SmallVector<StringRef, 8> SSNs;
2376   M.getContext().getSyncScopeNames(SSNs);
2377   if (SSNs.empty())
2378     return;
2379 
2380   Stream.EnterSubblock(bitc::SYNC_SCOPE_NAMES_BLOCK_ID, 2);
2381 
2382   SmallVector<uint64_t, 64> Record;
2383   for (auto SSN : SSNs) {
2384     Record.append(SSN.begin(), SSN.end());
2385     Stream.EmitRecord(bitc::SYNC_SCOPE_NAME, Record, 0);
2386     Record.clear();
2387   }
2388 
2389   Stream.ExitBlock();
2390 }
2391 
2392 void ModuleBitcodeWriter::writeConstants(unsigned FirstVal, unsigned LastVal,
2393                                          bool isGlobal) {
2394   if (FirstVal == LastVal) return;
2395 
2396   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
2397 
2398   unsigned AggregateAbbrev = 0;
2399   unsigned String8Abbrev = 0;
2400   unsigned CString7Abbrev = 0;
2401   unsigned CString6Abbrev = 0;
2402   // If this is a constant pool for the module, emit module-specific abbrevs.
2403   if (isGlobal) {
2404     // Abbrev for CST_CODE_AGGREGATE.
2405     auto Abbv = std::make_shared<BitCodeAbbrev>();
2406     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
2407     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2408     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
2409     AggregateAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2410 
2411     // Abbrev for CST_CODE_STRING.
2412     Abbv = std::make_shared<BitCodeAbbrev>();
2413     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
2414     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2415     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2416     String8Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2417     // Abbrev for CST_CODE_CSTRING.
2418     Abbv = std::make_shared<BitCodeAbbrev>();
2419     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2420     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2421     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2422     CString7Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2423     // Abbrev for CST_CODE_CSTRING.
2424     Abbv = std::make_shared<BitCodeAbbrev>();
2425     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2426     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2427     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2428     CString6Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2429   }
2430 
2431   SmallVector<uint64_t, 64> Record;
2432 
2433   const ValueEnumerator::ValueList &Vals = VE.getValues();
2434   Type *LastTy = nullptr;
2435   for (unsigned i = FirstVal; i != LastVal; ++i) {
2436     const Value *V = Vals[i].first;
2437     // If we need to switch types, do so now.
2438     if (V->getType() != LastTy) {
2439       LastTy = V->getType();
2440       Record.push_back(VE.getTypeID(LastTy));
2441       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
2442                         CONSTANTS_SETTYPE_ABBREV);
2443       Record.clear();
2444     }
2445 
2446     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
2447       Record.push_back(
2448           unsigned(IA->hasSideEffects()) | unsigned(IA->isAlignStack()) << 1 |
2449           unsigned(IA->getDialect() & 1) << 2 | unsigned(IA->canThrow()) << 3);
2450 
2451       // Add the asm string.
2452       const std::string &AsmStr = IA->getAsmString();
2453       Record.push_back(AsmStr.size());
2454       Record.append(AsmStr.begin(), AsmStr.end());
2455 
2456       // Add the constraint string.
2457       const std::string &ConstraintStr = IA->getConstraintString();
2458       Record.push_back(ConstraintStr.size());
2459       Record.append(ConstraintStr.begin(), ConstraintStr.end());
2460       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
2461       Record.clear();
2462       continue;
2463     }
2464     const Constant *C = cast<Constant>(V);
2465     unsigned Code = -1U;
2466     unsigned AbbrevToUse = 0;
2467     if (C->isNullValue()) {
2468       Code = bitc::CST_CODE_NULL;
2469     } else if (isa<PoisonValue>(C)) {
2470       Code = bitc::CST_CODE_POISON;
2471     } else if (isa<UndefValue>(C)) {
2472       Code = bitc::CST_CODE_UNDEF;
2473     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
2474       if (IV->getBitWidth() <= 64) {
2475         uint64_t V = IV->getSExtValue();
2476         emitSignedInt64(Record, V);
2477         Code = bitc::CST_CODE_INTEGER;
2478         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
2479       } else {                             // Wide integers, > 64 bits in size.
2480         emitWideAPInt(Record, IV->getValue());
2481         Code = bitc::CST_CODE_WIDE_INTEGER;
2482       }
2483     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
2484       Code = bitc::CST_CODE_FLOAT;
2485       Type *Ty = CFP->getType();
2486       if (Ty->isHalfTy() || Ty->isBFloatTy() || Ty->isFloatTy() ||
2487           Ty->isDoubleTy()) {
2488         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
2489       } else if (Ty->isX86_FP80Ty()) {
2490         // api needed to prevent premature destruction
2491         // bits are not in the same order as a normal i80 APInt, compensate.
2492         APInt api = CFP->getValueAPF().bitcastToAPInt();
2493         const uint64_t *p = api.getRawData();
2494         Record.push_back((p[1] << 48) | (p[0] >> 16));
2495         Record.push_back(p[0] & 0xffffLL);
2496       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
2497         APInt api = CFP->getValueAPF().bitcastToAPInt();
2498         const uint64_t *p = api.getRawData();
2499         Record.push_back(p[0]);
2500         Record.push_back(p[1]);
2501       } else {
2502         assert(0 && "Unknown FP type!");
2503       }
2504     } else if (isa<ConstantDataSequential>(C) &&
2505                cast<ConstantDataSequential>(C)->isString()) {
2506       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
2507       // Emit constant strings specially.
2508       unsigned NumElts = Str->getNumElements();
2509       // If this is a null-terminated string, use the denser CSTRING encoding.
2510       if (Str->isCString()) {
2511         Code = bitc::CST_CODE_CSTRING;
2512         --NumElts;  // Don't encode the null, which isn't allowed by char6.
2513       } else {
2514         Code = bitc::CST_CODE_STRING;
2515         AbbrevToUse = String8Abbrev;
2516       }
2517       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
2518       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
2519       for (unsigned i = 0; i != NumElts; ++i) {
2520         unsigned char V = Str->getElementAsInteger(i);
2521         Record.push_back(V);
2522         isCStr7 &= (V & 128) == 0;
2523         if (isCStrChar6)
2524           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
2525       }
2526 
2527       if (isCStrChar6)
2528         AbbrevToUse = CString6Abbrev;
2529       else if (isCStr7)
2530         AbbrevToUse = CString7Abbrev;
2531     } else if (const ConstantDataSequential *CDS =
2532                   dyn_cast<ConstantDataSequential>(C)) {
2533       Code = bitc::CST_CODE_DATA;
2534       Type *EltTy = CDS->getElementType();
2535       if (isa<IntegerType>(EltTy)) {
2536         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2537           Record.push_back(CDS->getElementAsInteger(i));
2538       } else {
2539         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2540           Record.push_back(
2541               CDS->getElementAsAPFloat(i).bitcastToAPInt().getLimitedValue());
2542       }
2543     } else if (isa<ConstantAggregate>(C)) {
2544       Code = bitc::CST_CODE_AGGREGATE;
2545       for (const Value *Op : C->operands())
2546         Record.push_back(VE.getValueID(Op));
2547       AbbrevToUse = AggregateAbbrev;
2548     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
2549       switch (CE->getOpcode()) {
2550       default:
2551         if (Instruction::isCast(CE->getOpcode())) {
2552           Code = bitc::CST_CODE_CE_CAST;
2553           Record.push_back(getEncodedCastOpcode(CE->getOpcode()));
2554           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2555           Record.push_back(VE.getValueID(C->getOperand(0)));
2556           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
2557         } else {
2558           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
2559           Code = bitc::CST_CODE_CE_BINOP;
2560           Record.push_back(getEncodedBinaryOpcode(CE->getOpcode()));
2561           Record.push_back(VE.getValueID(C->getOperand(0)));
2562           Record.push_back(VE.getValueID(C->getOperand(1)));
2563           uint64_t Flags = getOptimizationFlags(CE);
2564           if (Flags != 0)
2565             Record.push_back(Flags);
2566         }
2567         break;
2568       case Instruction::FNeg: {
2569         assert(CE->getNumOperands() == 1 && "Unknown constant expr!");
2570         Code = bitc::CST_CODE_CE_UNOP;
2571         Record.push_back(getEncodedUnaryOpcode(CE->getOpcode()));
2572         Record.push_back(VE.getValueID(C->getOperand(0)));
2573         uint64_t Flags = getOptimizationFlags(CE);
2574         if (Flags != 0)
2575           Record.push_back(Flags);
2576         break;
2577       }
2578       case Instruction::GetElementPtr: {
2579         Code = bitc::CST_CODE_CE_GEP;
2580         const auto *GO = cast<GEPOperator>(C);
2581         Record.push_back(VE.getTypeID(GO->getSourceElementType()));
2582         if (Optional<unsigned> Idx = GO->getInRangeIndex()) {
2583           Code = bitc::CST_CODE_CE_GEP_WITH_INRANGE_INDEX;
2584           Record.push_back((*Idx << 1) | GO->isInBounds());
2585         } else if (GO->isInBounds())
2586           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
2587         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
2588           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
2589           Record.push_back(VE.getValueID(C->getOperand(i)));
2590         }
2591         break;
2592       }
2593       case Instruction::Select:
2594         Code = bitc::CST_CODE_CE_SELECT;
2595         Record.push_back(VE.getValueID(C->getOperand(0)));
2596         Record.push_back(VE.getValueID(C->getOperand(1)));
2597         Record.push_back(VE.getValueID(C->getOperand(2)));
2598         break;
2599       case Instruction::ExtractElement:
2600         Code = bitc::CST_CODE_CE_EXTRACTELT;
2601         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2602         Record.push_back(VE.getValueID(C->getOperand(0)));
2603         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
2604         Record.push_back(VE.getValueID(C->getOperand(1)));
2605         break;
2606       case Instruction::InsertElement:
2607         Code = bitc::CST_CODE_CE_INSERTELT;
2608         Record.push_back(VE.getValueID(C->getOperand(0)));
2609         Record.push_back(VE.getValueID(C->getOperand(1)));
2610         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
2611         Record.push_back(VE.getValueID(C->getOperand(2)));
2612         break;
2613       case Instruction::ShuffleVector:
2614         // If the return type and argument types are the same, this is a
2615         // standard shufflevector instruction.  If the types are different,
2616         // then the shuffle is widening or truncating the input vectors, and
2617         // the argument type must also be encoded.
2618         if (C->getType() == C->getOperand(0)->getType()) {
2619           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
2620         } else {
2621           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
2622           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2623         }
2624         Record.push_back(VE.getValueID(C->getOperand(0)));
2625         Record.push_back(VE.getValueID(C->getOperand(1)));
2626         Record.push_back(VE.getValueID(CE->getShuffleMaskForBitcode()));
2627         break;
2628       case Instruction::ICmp:
2629       case Instruction::FCmp:
2630         Code = bitc::CST_CODE_CE_CMP;
2631         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2632         Record.push_back(VE.getValueID(C->getOperand(0)));
2633         Record.push_back(VE.getValueID(C->getOperand(1)));
2634         Record.push_back(CE->getPredicate());
2635         break;
2636       }
2637     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
2638       Code = bitc::CST_CODE_BLOCKADDRESS;
2639       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
2640       Record.push_back(VE.getValueID(BA->getFunction()));
2641       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
2642     } else if (const auto *Equiv = dyn_cast<DSOLocalEquivalent>(C)) {
2643       Code = bitc::CST_CODE_DSO_LOCAL_EQUIVALENT;
2644       Record.push_back(VE.getTypeID(Equiv->getGlobalValue()->getType()));
2645       Record.push_back(VE.getValueID(Equiv->getGlobalValue()));
2646     } else {
2647 #ifndef NDEBUG
2648       C->dump();
2649 #endif
2650       llvm_unreachable("Unknown constant!");
2651     }
2652     Stream.EmitRecord(Code, Record, AbbrevToUse);
2653     Record.clear();
2654   }
2655 
2656   Stream.ExitBlock();
2657 }
2658 
2659 void ModuleBitcodeWriter::writeModuleConstants() {
2660   const ValueEnumerator::ValueList &Vals = VE.getValues();
2661 
2662   // Find the first constant to emit, which is the first non-globalvalue value.
2663   // We know globalvalues have been emitted by WriteModuleInfo.
2664   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
2665     if (!isa<GlobalValue>(Vals[i].first)) {
2666       writeConstants(i, Vals.size(), true);
2667       return;
2668     }
2669   }
2670 }
2671 
2672 /// pushValueAndType - The file has to encode both the value and type id for
2673 /// many values, because we need to know what type to create for forward
2674 /// references.  However, most operands are not forward references, so this type
2675 /// field is not needed.
2676 ///
2677 /// This function adds V's value ID to Vals.  If the value ID is higher than the
2678 /// instruction ID, then it is a forward reference, and it also includes the
2679 /// type ID.  The value ID that is written is encoded relative to the InstID.
2680 bool ModuleBitcodeWriter::pushValueAndType(const Value *V, unsigned InstID,
2681                                            SmallVectorImpl<unsigned> &Vals) {
2682   unsigned ValID = VE.getValueID(V);
2683   // Make encoding relative to the InstID.
2684   Vals.push_back(InstID - ValID);
2685   if (ValID >= InstID) {
2686     Vals.push_back(VE.getTypeID(V->getType()));
2687     return true;
2688   }
2689   return false;
2690 }
2691 
2692 void ModuleBitcodeWriter::writeOperandBundles(const CallBase &CS,
2693                                               unsigned InstID) {
2694   SmallVector<unsigned, 64> Record;
2695   LLVMContext &C = CS.getContext();
2696 
2697   for (unsigned i = 0, e = CS.getNumOperandBundles(); i != e; ++i) {
2698     const auto &Bundle = CS.getOperandBundleAt(i);
2699     Record.push_back(C.getOperandBundleTagID(Bundle.getTagName()));
2700 
2701     for (auto &Input : Bundle.Inputs)
2702       pushValueAndType(Input, InstID, Record);
2703 
2704     Stream.EmitRecord(bitc::FUNC_CODE_OPERAND_BUNDLE, Record);
2705     Record.clear();
2706   }
2707 }
2708 
2709 /// pushValue - Like pushValueAndType, but where the type of the value is
2710 /// omitted (perhaps it was already encoded in an earlier operand).
2711 void ModuleBitcodeWriter::pushValue(const Value *V, unsigned InstID,
2712                                     SmallVectorImpl<unsigned> &Vals) {
2713   unsigned ValID = VE.getValueID(V);
2714   Vals.push_back(InstID - ValID);
2715 }
2716 
2717 void ModuleBitcodeWriter::pushValueSigned(const Value *V, unsigned InstID,
2718                                           SmallVectorImpl<uint64_t> &Vals) {
2719   unsigned ValID = VE.getValueID(V);
2720   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
2721   emitSignedInt64(Vals, diff);
2722 }
2723 
2724 /// WriteInstruction - Emit an instruction to the specified stream.
2725 void ModuleBitcodeWriter::writeInstruction(const Instruction &I,
2726                                            unsigned InstID,
2727                                            SmallVectorImpl<unsigned> &Vals) {
2728   unsigned Code = 0;
2729   unsigned AbbrevToUse = 0;
2730   VE.setInstructionID(&I);
2731   switch (I.getOpcode()) {
2732   default:
2733     if (Instruction::isCast(I.getOpcode())) {
2734       Code = bitc::FUNC_CODE_INST_CAST;
2735       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2736         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
2737       Vals.push_back(VE.getTypeID(I.getType()));
2738       Vals.push_back(getEncodedCastOpcode(I.getOpcode()));
2739     } else {
2740       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
2741       Code = bitc::FUNC_CODE_INST_BINOP;
2742       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2743         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
2744       pushValue(I.getOperand(1), InstID, Vals);
2745       Vals.push_back(getEncodedBinaryOpcode(I.getOpcode()));
2746       uint64_t Flags = getOptimizationFlags(&I);
2747       if (Flags != 0) {
2748         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
2749           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
2750         Vals.push_back(Flags);
2751       }
2752     }
2753     break;
2754   case Instruction::FNeg: {
2755     Code = bitc::FUNC_CODE_INST_UNOP;
2756     if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2757       AbbrevToUse = FUNCTION_INST_UNOP_ABBREV;
2758     Vals.push_back(getEncodedUnaryOpcode(I.getOpcode()));
2759     uint64_t Flags = getOptimizationFlags(&I);
2760     if (Flags != 0) {
2761       if (AbbrevToUse == FUNCTION_INST_UNOP_ABBREV)
2762         AbbrevToUse = FUNCTION_INST_UNOP_FLAGS_ABBREV;
2763       Vals.push_back(Flags);
2764     }
2765     break;
2766   }
2767   case Instruction::GetElementPtr: {
2768     Code = bitc::FUNC_CODE_INST_GEP;
2769     AbbrevToUse = FUNCTION_INST_GEP_ABBREV;
2770     auto &GEPInst = cast<GetElementPtrInst>(I);
2771     Vals.push_back(GEPInst.isInBounds());
2772     Vals.push_back(VE.getTypeID(GEPInst.getSourceElementType()));
2773     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
2774       pushValueAndType(I.getOperand(i), InstID, Vals);
2775     break;
2776   }
2777   case Instruction::ExtractValue: {
2778     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
2779     pushValueAndType(I.getOperand(0), InstID, Vals);
2780     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
2781     Vals.append(EVI->idx_begin(), EVI->idx_end());
2782     break;
2783   }
2784   case Instruction::InsertValue: {
2785     Code = bitc::FUNC_CODE_INST_INSERTVAL;
2786     pushValueAndType(I.getOperand(0), InstID, Vals);
2787     pushValueAndType(I.getOperand(1), InstID, Vals);
2788     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
2789     Vals.append(IVI->idx_begin(), IVI->idx_end());
2790     break;
2791   }
2792   case Instruction::Select: {
2793     Code = bitc::FUNC_CODE_INST_VSELECT;
2794     pushValueAndType(I.getOperand(1), InstID, Vals);
2795     pushValue(I.getOperand(2), InstID, Vals);
2796     pushValueAndType(I.getOperand(0), InstID, Vals);
2797     uint64_t Flags = getOptimizationFlags(&I);
2798     if (Flags != 0)
2799       Vals.push_back(Flags);
2800     break;
2801   }
2802   case Instruction::ExtractElement:
2803     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
2804     pushValueAndType(I.getOperand(0), InstID, Vals);
2805     pushValueAndType(I.getOperand(1), InstID, Vals);
2806     break;
2807   case Instruction::InsertElement:
2808     Code = bitc::FUNC_CODE_INST_INSERTELT;
2809     pushValueAndType(I.getOperand(0), InstID, Vals);
2810     pushValue(I.getOperand(1), InstID, Vals);
2811     pushValueAndType(I.getOperand(2), InstID, Vals);
2812     break;
2813   case Instruction::ShuffleVector:
2814     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
2815     pushValueAndType(I.getOperand(0), InstID, Vals);
2816     pushValue(I.getOperand(1), InstID, Vals);
2817     pushValue(cast<ShuffleVectorInst>(I).getShuffleMaskForBitcode(), InstID,
2818               Vals);
2819     break;
2820   case Instruction::ICmp:
2821   case Instruction::FCmp: {
2822     // compare returning Int1Ty or vector of Int1Ty
2823     Code = bitc::FUNC_CODE_INST_CMP2;
2824     pushValueAndType(I.getOperand(0), InstID, Vals);
2825     pushValue(I.getOperand(1), InstID, Vals);
2826     Vals.push_back(cast<CmpInst>(I).getPredicate());
2827     uint64_t Flags = getOptimizationFlags(&I);
2828     if (Flags != 0)
2829       Vals.push_back(Flags);
2830     break;
2831   }
2832 
2833   case Instruction::Ret:
2834     {
2835       Code = bitc::FUNC_CODE_INST_RET;
2836       unsigned NumOperands = I.getNumOperands();
2837       if (NumOperands == 0)
2838         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
2839       else if (NumOperands == 1) {
2840         if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2841           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
2842       } else {
2843         for (unsigned i = 0, e = NumOperands; i != e; ++i)
2844           pushValueAndType(I.getOperand(i), InstID, Vals);
2845       }
2846     }
2847     break;
2848   case Instruction::Br:
2849     {
2850       Code = bitc::FUNC_CODE_INST_BR;
2851       const BranchInst &II = cast<BranchInst>(I);
2852       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
2853       if (II.isConditional()) {
2854         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
2855         pushValue(II.getCondition(), InstID, Vals);
2856       }
2857     }
2858     break;
2859   case Instruction::Switch:
2860     {
2861       Code = bitc::FUNC_CODE_INST_SWITCH;
2862       const SwitchInst &SI = cast<SwitchInst>(I);
2863       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
2864       pushValue(SI.getCondition(), InstID, Vals);
2865       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
2866       for (auto Case : SI.cases()) {
2867         Vals.push_back(VE.getValueID(Case.getCaseValue()));
2868         Vals.push_back(VE.getValueID(Case.getCaseSuccessor()));
2869       }
2870     }
2871     break;
2872   case Instruction::IndirectBr:
2873     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
2874     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2875     // Encode the address operand as relative, but not the basic blocks.
2876     pushValue(I.getOperand(0), InstID, Vals);
2877     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
2878       Vals.push_back(VE.getValueID(I.getOperand(i)));
2879     break;
2880 
2881   case Instruction::Invoke: {
2882     const InvokeInst *II = cast<InvokeInst>(&I);
2883     const Value *Callee = II->getCalledOperand();
2884     FunctionType *FTy = II->getFunctionType();
2885 
2886     if (II->hasOperandBundles())
2887       writeOperandBundles(*II, InstID);
2888 
2889     Code = bitc::FUNC_CODE_INST_INVOKE;
2890 
2891     Vals.push_back(VE.getAttributeListID(II->getAttributes()));
2892     Vals.push_back(II->getCallingConv() | 1 << 13);
2893     Vals.push_back(VE.getValueID(II->getNormalDest()));
2894     Vals.push_back(VE.getValueID(II->getUnwindDest()));
2895     Vals.push_back(VE.getTypeID(FTy));
2896     pushValueAndType(Callee, InstID, Vals);
2897 
2898     // Emit value #'s for the fixed parameters.
2899     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
2900       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
2901 
2902     // Emit type/value pairs for varargs params.
2903     if (FTy->isVarArg()) {
2904       for (unsigned i = FTy->getNumParams(), e = II->getNumArgOperands();
2905            i != e; ++i)
2906         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
2907     }
2908     break;
2909   }
2910   case Instruction::Resume:
2911     Code = bitc::FUNC_CODE_INST_RESUME;
2912     pushValueAndType(I.getOperand(0), InstID, Vals);
2913     break;
2914   case Instruction::CleanupRet: {
2915     Code = bitc::FUNC_CODE_INST_CLEANUPRET;
2916     const auto &CRI = cast<CleanupReturnInst>(I);
2917     pushValue(CRI.getCleanupPad(), InstID, Vals);
2918     if (CRI.hasUnwindDest())
2919       Vals.push_back(VE.getValueID(CRI.getUnwindDest()));
2920     break;
2921   }
2922   case Instruction::CatchRet: {
2923     Code = bitc::FUNC_CODE_INST_CATCHRET;
2924     const auto &CRI = cast<CatchReturnInst>(I);
2925     pushValue(CRI.getCatchPad(), InstID, Vals);
2926     Vals.push_back(VE.getValueID(CRI.getSuccessor()));
2927     break;
2928   }
2929   case Instruction::CleanupPad:
2930   case Instruction::CatchPad: {
2931     const auto &FuncletPad = cast<FuncletPadInst>(I);
2932     Code = isa<CatchPadInst>(FuncletPad) ? bitc::FUNC_CODE_INST_CATCHPAD
2933                                          : bitc::FUNC_CODE_INST_CLEANUPPAD;
2934     pushValue(FuncletPad.getParentPad(), InstID, Vals);
2935 
2936     unsigned NumArgOperands = FuncletPad.getNumArgOperands();
2937     Vals.push_back(NumArgOperands);
2938     for (unsigned Op = 0; Op != NumArgOperands; ++Op)
2939       pushValueAndType(FuncletPad.getArgOperand(Op), InstID, Vals);
2940     break;
2941   }
2942   case Instruction::CatchSwitch: {
2943     Code = bitc::FUNC_CODE_INST_CATCHSWITCH;
2944     const auto &CatchSwitch = cast<CatchSwitchInst>(I);
2945 
2946     pushValue(CatchSwitch.getParentPad(), InstID, Vals);
2947 
2948     unsigned NumHandlers = CatchSwitch.getNumHandlers();
2949     Vals.push_back(NumHandlers);
2950     for (const BasicBlock *CatchPadBB : CatchSwitch.handlers())
2951       Vals.push_back(VE.getValueID(CatchPadBB));
2952 
2953     if (CatchSwitch.hasUnwindDest())
2954       Vals.push_back(VE.getValueID(CatchSwitch.getUnwindDest()));
2955     break;
2956   }
2957   case Instruction::CallBr: {
2958     const CallBrInst *CBI = cast<CallBrInst>(&I);
2959     const Value *Callee = CBI->getCalledOperand();
2960     FunctionType *FTy = CBI->getFunctionType();
2961 
2962     if (CBI->hasOperandBundles())
2963       writeOperandBundles(*CBI, InstID);
2964 
2965     Code = bitc::FUNC_CODE_INST_CALLBR;
2966 
2967     Vals.push_back(VE.getAttributeListID(CBI->getAttributes()));
2968 
2969     Vals.push_back(CBI->getCallingConv() << bitc::CALL_CCONV |
2970                    1 << bitc::CALL_EXPLICIT_TYPE);
2971 
2972     Vals.push_back(VE.getValueID(CBI->getDefaultDest()));
2973     Vals.push_back(CBI->getNumIndirectDests());
2974     for (unsigned i = 0, e = CBI->getNumIndirectDests(); i != e; ++i)
2975       Vals.push_back(VE.getValueID(CBI->getIndirectDest(i)));
2976 
2977     Vals.push_back(VE.getTypeID(FTy));
2978     pushValueAndType(Callee, InstID, Vals);
2979 
2980     // Emit value #'s for the fixed parameters.
2981     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
2982       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
2983 
2984     // Emit type/value pairs for varargs params.
2985     if (FTy->isVarArg()) {
2986       for (unsigned i = FTy->getNumParams(), e = CBI->getNumArgOperands();
2987            i != e; ++i)
2988         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
2989     }
2990     break;
2991   }
2992   case Instruction::Unreachable:
2993     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
2994     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
2995     break;
2996 
2997   case Instruction::PHI: {
2998     const PHINode &PN = cast<PHINode>(I);
2999     Code = bitc::FUNC_CODE_INST_PHI;
3000     // With the newer instruction encoding, forward references could give
3001     // negative valued IDs.  This is most common for PHIs, so we use
3002     // signed VBRs.
3003     SmallVector<uint64_t, 128> Vals64;
3004     Vals64.push_back(VE.getTypeID(PN.getType()));
3005     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
3006       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64);
3007       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
3008     }
3009 
3010     uint64_t Flags = getOptimizationFlags(&I);
3011     if (Flags != 0)
3012       Vals64.push_back(Flags);
3013 
3014     // Emit a Vals64 vector and exit.
3015     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
3016     Vals64.clear();
3017     return;
3018   }
3019 
3020   case Instruction::LandingPad: {
3021     const LandingPadInst &LP = cast<LandingPadInst>(I);
3022     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
3023     Vals.push_back(VE.getTypeID(LP.getType()));
3024     Vals.push_back(LP.isCleanup());
3025     Vals.push_back(LP.getNumClauses());
3026     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
3027       if (LP.isCatch(I))
3028         Vals.push_back(LandingPadInst::Catch);
3029       else
3030         Vals.push_back(LandingPadInst::Filter);
3031       pushValueAndType(LP.getClause(I), InstID, Vals);
3032     }
3033     break;
3034   }
3035 
3036   case Instruction::Alloca: {
3037     Code = bitc::FUNC_CODE_INST_ALLOCA;
3038     const AllocaInst &AI = cast<AllocaInst>(I);
3039     Vals.push_back(VE.getTypeID(AI.getAllocatedType()));
3040     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
3041     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
3042     using APV = AllocaPackedValues;
3043     unsigned Record = 0;
3044     Bitfield::set<APV::Align>(Record, getEncodedAlign(AI.getAlign()));
3045     Bitfield::set<APV::UsedWithInAlloca>(Record, AI.isUsedWithInAlloca());
3046     Bitfield::set<APV::ExplicitType>(Record, true);
3047     Bitfield::set<APV::SwiftError>(Record, AI.isSwiftError());
3048     Vals.push_back(Record);
3049     break;
3050   }
3051 
3052   case Instruction::Load:
3053     if (cast<LoadInst>(I).isAtomic()) {
3054       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
3055       pushValueAndType(I.getOperand(0), InstID, Vals);
3056     } else {
3057       Code = bitc::FUNC_CODE_INST_LOAD;
3058       if (!pushValueAndType(I.getOperand(0), InstID, Vals)) // ptr
3059         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
3060     }
3061     Vals.push_back(VE.getTypeID(I.getType()));
3062     Vals.push_back(getEncodedAlign(cast<LoadInst>(I).getAlign()));
3063     Vals.push_back(cast<LoadInst>(I).isVolatile());
3064     if (cast<LoadInst>(I).isAtomic()) {
3065       Vals.push_back(getEncodedOrdering(cast<LoadInst>(I).getOrdering()));
3066       Vals.push_back(getEncodedSyncScopeID(cast<LoadInst>(I).getSyncScopeID()));
3067     }
3068     break;
3069   case Instruction::Store:
3070     if (cast<StoreInst>(I).isAtomic())
3071       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
3072     else
3073       Code = bitc::FUNC_CODE_INST_STORE;
3074     pushValueAndType(I.getOperand(1), InstID, Vals); // ptrty + ptr
3075     pushValueAndType(I.getOperand(0), InstID, Vals); // valty + val
3076     Vals.push_back(getEncodedAlign(cast<StoreInst>(I).getAlign()));
3077     Vals.push_back(cast<StoreInst>(I).isVolatile());
3078     if (cast<StoreInst>(I).isAtomic()) {
3079       Vals.push_back(getEncodedOrdering(cast<StoreInst>(I).getOrdering()));
3080       Vals.push_back(
3081           getEncodedSyncScopeID(cast<StoreInst>(I).getSyncScopeID()));
3082     }
3083     break;
3084   case Instruction::AtomicCmpXchg:
3085     Code = bitc::FUNC_CODE_INST_CMPXCHG;
3086     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
3087     pushValueAndType(I.getOperand(1), InstID, Vals); // cmp.
3088     pushValue(I.getOperand(2), InstID, Vals);        // newval.
3089     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
3090     Vals.push_back(
3091         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
3092     Vals.push_back(
3093         getEncodedSyncScopeID(cast<AtomicCmpXchgInst>(I).getSyncScopeID()));
3094     Vals.push_back(
3095         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
3096     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
3097     Vals.push_back(getEncodedAlign(cast<AtomicCmpXchgInst>(I).getAlign()));
3098     break;
3099   case Instruction::AtomicRMW:
3100     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
3101     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
3102     pushValue(I.getOperand(1), InstID, Vals);        // val.
3103     Vals.push_back(
3104         getEncodedRMWOperation(cast<AtomicRMWInst>(I).getOperation()));
3105     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
3106     Vals.push_back(getEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
3107     Vals.push_back(
3108         getEncodedSyncScopeID(cast<AtomicRMWInst>(I).getSyncScopeID()));
3109     Vals.push_back(getEncodedAlign(cast<AtomicRMWInst>(I).getAlign()));
3110     break;
3111   case Instruction::Fence:
3112     Code = bitc::FUNC_CODE_INST_FENCE;
3113     Vals.push_back(getEncodedOrdering(cast<FenceInst>(I).getOrdering()));
3114     Vals.push_back(getEncodedSyncScopeID(cast<FenceInst>(I).getSyncScopeID()));
3115     break;
3116   case Instruction::Call: {
3117     const CallInst &CI = cast<CallInst>(I);
3118     FunctionType *FTy = CI.getFunctionType();
3119 
3120     if (CI.hasOperandBundles())
3121       writeOperandBundles(CI, InstID);
3122 
3123     Code = bitc::FUNC_CODE_INST_CALL;
3124 
3125     Vals.push_back(VE.getAttributeListID(CI.getAttributes()));
3126 
3127     unsigned Flags = getOptimizationFlags(&I);
3128     Vals.push_back(CI.getCallingConv() << bitc::CALL_CCONV |
3129                    unsigned(CI.isTailCall()) << bitc::CALL_TAIL |
3130                    unsigned(CI.isMustTailCall()) << bitc::CALL_MUSTTAIL |
3131                    1 << bitc::CALL_EXPLICIT_TYPE |
3132                    unsigned(CI.isNoTailCall()) << bitc::CALL_NOTAIL |
3133                    unsigned(Flags != 0) << bitc::CALL_FMF);
3134     if (Flags != 0)
3135       Vals.push_back(Flags);
3136 
3137     Vals.push_back(VE.getTypeID(FTy));
3138     pushValueAndType(CI.getCalledOperand(), InstID, Vals); // Callee
3139 
3140     // Emit value #'s for the fixed parameters.
3141     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
3142       // Check for labels (can happen with asm labels).
3143       if (FTy->getParamType(i)->isLabelTy())
3144         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
3145       else
3146         pushValue(CI.getArgOperand(i), InstID, Vals); // fixed param.
3147     }
3148 
3149     // Emit type/value pairs for varargs params.
3150     if (FTy->isVarArg()) {
3151       for (unsigned i = FTy->getNumParams(), e = CI.getNumArgOperands();
3152            i != e; ++i)
3153         pushValueAndType(CI.getArgOperand(i), InstID, Vals); // varargs
3154     }
3155     break;
3156   }
3157   case Instruction::VAArg:
3158     Code = bitc::FUNC_CODE_INST_VAARG;
3159     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
3160     pushValue(I.getOperand(0), InstID, Vals);                   // valist.
3161     Vals.push_back(VE.getTypeID(I.getType())); // restype.
3162     break;
3163   case Instruction::Freeze:
3164     Code = bitc::FUNC_CODE_INST_FREEZE;
3165     pushValueAndType(I.getOperand(0), InstID, Vals);
3166     break;
3167   }
3168 
3169   Stream.EmitRecord(Code, Vals, AbbrevToUse);
3170   Vals.clear();
3171 }
3172 
3173 /// Write a GlobalValue VST to the module. The purpose of this data structure is
3174 /// to allow clients to efficiently find the function body.
3175 void ModuleBitcodeWriter::writeGlobalValueSymbolTable(
3176   DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3177   // Get the offset of the VST we are writing, and backpatch it into
3178   // the VST forward declaration record.
3179   uint64_t VSTOffset = Stream.GetCurrentBitNo();
3180   // The BitcodeStartBit was the stream offset of the identification block.
3181   VSTOffset -= bitcodeStartBit();
3182   assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
3183   // Note that we add 1 here because the offset is relative to one word
3184   // before the start of the identification block, which was historically
3185   // always the start of the regular bitcode header.
3186   Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32 + 1);
3187 
3188   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3189 
3190   auto Abbv = std::make_shared<BitCodeAbbrev>();
3191   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
3192   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
3193   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
3194   unsigned FnEntryAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3195 
3196   for (const Function &F : M) {
3197     uint64_t Record[2];
3198 
3199     if (F.isDeclaration())
3200       continue;
3201 
3202     Record[0] = VE.getValueID(&F);
3203 
3204     // Save the word offset of the function (from the start of the
3205     // actual bitcode written to the stream).
3206     uint64_t BitcodeIndex = FunctionToBitcodeIndex[&F] - bitcodeStartBit();
3207     assert((BitcodeIndex & 31) == 0 && "function block not 32-bit aligned");
3208     // Note that we add 1 here because the offset is relative to one word
3209     // before the start of the identification block, which was historically
3210     // always the start of the regular bitcode header.
3211     Record[1] = BitcodeIndex / 32 + 1;
3212 
3213     Stream.EmitRecord(bitc::VST_CODE_FNENTRY, Record, FnEntryAbbrev);
3214   }
3215 
3216   Stream.ExitBlock();
3217 }
3218 
3219 /// Emit names for arguments, instructions and basic blocks in a function.
3220 void ModuleBitcodeWriter::writeFunctionLevelValueSymbolTable(
3221     const ValueSymbolTable &VST) {
3222   if (VST.empty())
3223     return;
3224 
3225   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3226 
3227   // FIXME: Set up the abbrev, we know how many values there are!
3228   // FIXME: We know if the type names can use 7-bit ascii.
3229   SmallVector<uint64_t, 64> NameVals;
3230 
3231   for (const ValueName &Name : VST) {
3232     // Figure out the encoding to use for the name.
3233     StringEncoding Bits = getStringEncoding(Name.getKey());
3234 
3235     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
3236     NameVals.push_back(VE.getValueID(Name.getValue()));
3237 
3238     // VST_CODE_ENTRY:   [valueid, namechar x N]
3239     // VST_CODE_BBENTRY: [bbid, namechar x N]
3240     unsigned Code;
3241     if (isa<BasicBlock>(Name.getValue())) {
3242       Code = bitc::VST_CODE_BBENTRY;
3243       if (Bits == SE_Char6)
3244         AbbrevToUse = VST_BBENTRY_6_ABBREV;
3245     } else {
3246       Code = bitc::VST_CODE_ENTRY;
3247       if (Bits == SE_Char6)
3248         AbbrevToUse = VST_ENTRY_6_ABBREV;
3249       else if (Bits == SE_Fixed7)
3250         AbbrevToUse = VST_ENTRY_7_ABBREV;
3251     }
3252 
3253     for (const auto P : Name.getKey())
3254       NameVals.push_back((unsigned char)P);
3255 
3256     // Emit the finished record.
3257     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
3258     NameVals.clear();
3259   }
3260 
3261   Stream.ExitBlock();
3262 }
3263 
3264 void ModuleBitcodeWriter::writeUseList(UseListOrder &&Order) {
3265   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
3266   unsigned Code;
3267   if (isa<BasicBlock>(Order.V))
3268     Code = bitc::USELIST_CODE_BB;
3269   else
3270     Code = bitc::USELIST_CODE_DEFAULT;
3271 
3272   SmallVector<uint64_t, 64> Record(Order.Shuffle.begin(), Order.Shuffle.end());
3273   Record.push_back(VE.getValueID(Order.V));
3274   Stream.EmitRecord(Code, Record);
3275 }
3276 
3277 void ModuleBitcodeWriter::writeUseListBlock(const Function *F) {
3278   assert(VE.shouldPreserveUseListOrder() &&
3279          "Expected to be preserving use-list order");
3280 
3281   auto hasMore = [&]() {
3282     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
3283   };
3284   if (!hasMore())
3285     // Nothing to do.
3286     return;
3287 
3288   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
3289   while (hasMore()) {
3290     writeUseList(std::move(VE.UseListOrders.back()));
3291     VE.UseListOrders.pop_back();
3292   }
3293   Stream.ExitBlock();
3294 }
3295 
3296 /// Emit a function body to the module stream.
3297 void ModuleBitcodeWriter::writeFunction(
3298     const Function &F,
3299     DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3300   // Save the bitcode index of the start of this function block for recording
3301   // in the VST.
3302   FunctionToBitcodeIndex[&F] = Stream.GetCurrentBitNo();
3303 
3304   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
3305   VE.incorporateFunction(F);
3306 
3307   SmallVector<unsigned, 64> Vals;
3308 
3309   // Emit the number of basic blocks, so the reader can create them ahead of
3310   // time.
3311   Vals.push_back(VE.getBasicBlocks().size());
3312   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
3313   Vals.clear();
3314 
3315   // If there are function-local constants, emit them now.
3316   unsigned CstStart, CstEnd;
3317   VE.getFunctionConstantRange(CstStart, CstEnd);
3318   writeConstants(CstStart, CstEnd, false);
3319 
3320   // If there is function-local metadata, emit it now.
3321   writeFunctionMetadata(F);
3322 
3323   // Keep a running idea of what the instruction ID is.
3324   unsigned InstID = CstEnd;
3325 
3326   bool NeedsMetadataAttachment = F.hasMetadata();
3327 
3328   DILocation *LastDL = nullptr;
3329   // Finally, emit all the instructions, in order.
3330   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
3331     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
3332          I != E; ++I) {
3333       writeInstruction(*I, InstID, Vals);
3334 
3335       if (!I->getType()->isVoidTy())
3336         ++InstID;
3337 
3338       // If the instruction has metadata, write a metadata attachment later.
3339       NeedsMetadataAttachment |= I->hasMetadataOtherThanDebugLoc();
3340 
3341       // If the instruction has a debug location, emit it.
3342       DILocation *DL = I->getDebugLoc();
3343       if (!DL)
3344         continue;
3345 
3346       if (DL == LastDL) {
3347         // Just repeat the same debug loc as last time.
3348         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
3349         continue;
3350       }
3351 
3352       Vals.push_back(DL->getLine());
3353       Vals.push_back(DL->getColumn());
3354       Vals.push_back(VE.getMetadataOrNullID(DL->getScope()));
3355       Vals.push_back(VE.getMetadataOrNullID(DL->getInlinedAt()));
3356       Vals.push_back(DL->isImplicitCode());
3357       Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
3358       Vals.clear();
3359 
3360       LastDL = DL;
3361     }
3362 
3363   // Emit names for all the instructions etc.
3364   if (auto *Symtab = F.getValueSymbolTable())
3365     writeFunctionLevelValueSymbolTable(*Symtab);
3366 
3367   if (NeedsMetadataAttachment)
3368     writeFunctionMetadataAttachment(F);
3369   if (VE.shouldPreserveUseListOrder())
3370     writeUseListBlock(&F);
3371   VE.purgeFunction();
3372   Stream.ExitBlock();
3373 }
3374 
3375 // Emit blockinfo, which defines the standard abbreviations etc.
3376 void ModuleBitcodeWriter::writeBlockInfo() {
3377   // We only want to emit block info records for blocks that have multiple
3378   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
3379   // Other blocks can define their abbrevs inline.
3380   Stream.EnterBlockInfoBlock();
3381 
3382   { // 8-bit fixed-width VST_CODE_ENTRY/VST_CODE_BBENTRY strings.
3383     auto Abbv = std::make_shared<BitCodeAbbrev>();
3384     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
3385     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3386     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3387     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3388     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3389         VST_ENTRY_8_ABBREV)
3390       llvm_unreachable("Unexpected abbrev ordering!");
3391   }
3392 
3393   { // 7-bit fixed width VST_CODE_ENTRY strings.
3394     auto Abbv = std::make_shared<BitCodeAbbrev>();
3395     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3396     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3397     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3398     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3399     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3400         VST_ENTRY_7_ABBREV)
3401       llvm_unreachable("Unexpected abbrev ordering!");
3402   }
3403   { // 6-bit char6 VST_CODE_ENTRY strings.
3404     auto Abbv = std::make_shared<BitCodeAbbrev>();
3405     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3406     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3407     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3408     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3409     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3410         VST_ENTRY_6_ABBREV)
3411       llvm_unreachable("Unexpected abbrev ordering!");
3412   }
3413   { // 6-bit char6 VST_CODE_BBENTRY strings.
3414     auto Abbv = std::make_shared<BitCodeAbbrev>();
3415     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
3416     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3417     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3418     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3419     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3420         VST_BBENTRY_6_ABBREV)
3421       llvm_unreachable("Unexpected abbrev ordering!");
3422   }
3423 
3424   { // SETTYPE abbrev for CONSTANTS_BLOCK.
3425     auto Abbv = std::make_shared<BitCodeAbbrev>();
3426     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
3427     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
3428                               VE.computeBitsRequiredForTypeIndicies()));
3429     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3430         CONSTANTS_SETTYPE_ABBREV)
3431       llvm_unreachable("Unexpected abbrev ordering!");
3432   }
3433 
3434   { // INTEGER abbrev for CONSTANTS_BLOCK.
3435     auto Abbv = std::make_shared<BitCodeAbbrev>();
3436     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
3437     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3438     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3439         CONSTANTS_INTEGER_ABBREV)
3440       llvm_unreachable("Unexpected abbrev ordering!");
3441   }
3442 
3443   { // CE_CAST abbrev for CONSTANTS_BLOCK.
3444     auto Abbv = std::make_shared<BitCodeAbbrev>();
3445     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
3446     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
3447     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
3448                               VE.computeBitsRequiredForTypeIndicies()));
3449     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
3450 
3451     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3452         CONSTANTS_CE_CAST_Abbrev)
3453       llvm_unreachable("Unexpected abbrev ordering!");
3454   }
3455   { // NULL abbrev for CONSTANTS_BLOCK.
3456     auto Abbv = std::make_shared<BitCodeAbbrev>();
3457     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
3458     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3459         CONSTANTS_NULL_Abbrev)
3460       llvm_unreachable("Unexpected abbrev ordering!");
3461   }
3462 
3463   // FIXME: This should only use space for first class types!
3464 
3465   { // INST_LOAD abbrev for FUNCTION_BLOCK.
3466     auto Abbv = std::make_shared<BitCodeAbbrev>();
3467     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
3468     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
3469     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
3470                               VE.computeBitsRequiredForTypeIndicies()));
3471     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
3472     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
3473     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3474         FUNCTION_INST_LOAD_ABBREV)
3475       llvm_unreachable("Unexpected abbrev ordering!");
3476   }
3477   { // INST_UNOP abbrev for FUNCTION_BLOCK.
3478     auto Abbv = std::make_shared<BitCodeAbbrev>();
3479     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3480     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3481     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3482     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3483         FUNCTION_INST_UNOP_ABBREV)
3484       llvm_unreachable("Unexpected abbrev ordering!");
3485   }
3486   { // INST_UNOP_FLAGS abbrev for FUNCTION_BLOCK.
3487     auto Abbv = std::make_shared<BitCodeAbbrev>();
3488     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3489     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3490     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3491     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3492     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3493         FUNCTION_INST_UNOP_FLAGS_ABBREV)
3494       llvm_unreachable("Unexpected abbrev ordering!");
3495   }
3496   { // INST_BINOP abbrev for FUNCTION_BLOCK.
3497     auto Abbv = std::make_shared<BitCodeAbbrev>();
3498     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3499     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3500     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3501     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3502     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3503         FUNCTION_INST_BINOP_ABBREV)
3504       llvm_unreachable("Unexpected abbrev ordering!");
3505   }
3506   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
3507     auto Abbv = std::make_shared<BitCodeAbbrev>();
3508     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3509     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3510     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3511     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3512     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3513     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3514         FUNCTION_INST_BINOP_FLAGS_ABBREV)
3515       llvm_unreachable("Unexpected abbrev ordering!");
3516   }
3517   { // INST_CAST abbrev for FUNCTION_BLOCK.
3518     auto Abbv = std::make_shared<BitCodeAbbrev>();
3519     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
3520     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
3521     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
3522                               VE.computeBitsRequiredForTypeIndicies()));
3523     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
3524     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3525         FUNCTION_INST_CAST_ABBREV)
3526       llvm_unreachable("Unexpected abbrev ordering!");
3527   }
3528 
3529   { // INST_RET abbrev for FUNCTION_BLOCK.
3530     auto Abbv = std::make_shared<BitCodeAbbrev>();
3531     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3532     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3533         FUNCTION_INST_RET_VOID_ABBREV)
3534       llvm_unreachable("Unexpected abbrev ordering!");
3535   }
3536   { // INST_RET abbrev for FUNCTION_BLOCK.
3537     auto Abbv = std::make_shared<BitCodeAbbrev>();
3538     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3539     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
3540     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3541         FUNCTION_INST_RET_VAL_ABBREV)
3542       llvm_unreachable("Unexpected abbrev ordering!");
3543   }
3544   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
3545     auto Abbv = std::make_shared<BitCodeAbbrev>();
3546     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
3547     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3548         FUNCTION_INST_UNREACHABLE_ABBREV)
3549       llvm_unreachable("Unexpected abbrev ordering!");
3550   }
3551   {
3552     auto Abbv = std::make_shared<BitCodeAbbrev>();
3553     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_GEP));
3554     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
3555     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, // dest ty
3556                               Log2_32_Ceil(VE.getTypes().size() + 1)));
3557     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3558     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
3559     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3560         FUNCTION_INST_GEP_ABBREV)
3561       llvm_unreachable("Unexpected abbrev ordering!");
3562   }
3563 
3564   Stream.ExitBlock();
3565 }
3566 
3567 /// Write the module path strings, currently only used when generating
3568 /// a combined index file.
3569 void IndexBitcodeWriter::writeModStrings() {
3570   Stream.EnterSubblock(bitc::MODULE_STRTAB_BLOCK_ID, 3);
3571 
3572   // TODO: See which abbrev sizes we actually need to emit
3573 
3574   // 8-bit fixed-width MST_ENTRY strings.
3575   auto Abbv = std::make_shared<BitCodeAbbrev>();
3576   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3577   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3578   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3579   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3580   unsigned Abbrev8Bit = Stream.EmitAbbrev(std::move(Abbv));
3581 
3582   // 7-bit fixed width MST_ENTRY strings.
3583   Abbv = std::make_shared<BitCodeAbbrev>();
3584   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3585   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3586   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3587   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3588   unsigned Abbrev7Bit = Stream.EmitAbbrev(std::move(Abbv));
3589 
3590   // 6-bit char6 MST_ENTRY strings.
3591   Abbv = std::make_shared<BitCodeAbbrev>();
3592   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3593   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3594   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3595   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3596   unsigned Abbrev6Bit = Stream.EmitAbbrev(std::move(Abbv));
3597 
3598   // Module Hash, 160 bits SHA1. Optionally, emitted after each MST_CODE_ENTRY.
3599   Abbv = std::make_shared<BitCodeAbbrev>();
3600   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_HASH));
3601   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3602   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3603   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3604   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3605   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3606   unsigned AbbrevHash = Stream.EmitAbbrev(std::move(Abbv));
3607 
3608   SmallVector<unsigned, 64> Vals;
3609   forEachModule(
3610       [&](const StringMapEntry<std::pair<uint64_t, ModuleHash>> &MPSE) {
3611         StringRef Key = MPSE.getKey();
3612         const auto &Value = MPSE.getValue();
3613         StringEncoding Bits = getStringEncoding(Key);
3614         unsigned AbbrevToUse = Abbrev8Bit;
3615         if (Bits == SE_Char6)
3616           AbbrevToUse = Abbrev6Bit;
3617         else if (Bits == SE_Fixed7)
3618           AbbrevToUse = Abbrev7Bit;
3619 
3620         Vals.push_back(Value.first);
3621         Vals.append(Key.begin(), Key.end());
3622 
3623         // Emit the finished record.
3624         Stream.EmitRecord(bitc::MST_CODE_ENTRY, Vals, AbbrevToUse);
3625 
3626         // Emit an optional hash for the module now
3627         const auto &Hash = Value.second;
3628         if (llvm::any_of(Hash, [](uint32_t H) { return H; })) {
3629           Vals.assign(Hash.begin(), Hash.end());
3630           // Emit the hash record.
3631           Stream.EmitRecord(bitc::MST_CODE_HASH, Vals, AbbrevHash);
3632         }
3633 
3634         Vals.clear();
3635       });
3636   Stream.ExitBlock();
3637 }
3638 
3639 /// Write the function type metadata related records that need to appear before
3640 /// a function summary entry (whether per-module or combined).
3641 template <typename Fn>
3642 static void writeFunctionTypeMetadataRecords(BitstreamWriter &Stream,
3643                                              FunctionSummary *FS,
3644                                              Fn GetValueID) {
3645   if (!FS->type_tests().empty())
3646     Stream.EmitRecord(bitc::FS_TYPE_TESTS, FS->type_tests());
3647 
3648   SmallVector<uint64_t, 64> Record;
3649 
3650   auto WriteVFuncIdVec = [&](uint64_t Ty,
3651                              ArrayRef<FunctionSummary::VFuncId> VFs) {
3652     if (VFs.empty())
3653       return;
3654     Record.clear();
3655     for (auto &VF : VFs) {
3656       Record.push_back(VF.GUID);
3657       Record.push_back(VF.Offset);
3658     }
3659     Stream.EmitRecord(Ty, Record);
3660   };
3661 
3662   WriteVFuncIdVec(bitc::FS_TYPE_TEST_ASSUME_VCALLS,
3663                   FS->type_test_assume_vcalls());
3664   WriteVFuncIdVec(bitc::FS_TYPE_CHECKED_LOAD_VCALLS,
3665                   FS->type_checked_load_vcalls());
3666 
3667   auto WriteConstVCallVec = [&](uint64_t Ty,
3668                                 ArrayRef<FunctionSummary::ConstVCall> VCs) {
3669     for (auto &VC : VCs) {
3670       Record.clear();
3671       Record.push_back(VC.VFunc.GUID);
3672       Record.push_back(VC.VFunc.Offset);
3673       llvm::append_range(Record, VC.Args);
3674       Stream.EmitRecord(Ty, Record);
3675     }
3676   };
3677 
3678   WriteConstVCallVec(bitc::FS_TYPE_TEST_ASSUME_CONST_VCALL,
3679                      FS->type_test_assume_const_vcalls());
3680   WriteConstVCallVec(bitc::FS_TYPE_CHECKED_LOAD_CONST_VCALL,
3681                      FS->type_checked_load_const_vcalls());
3682 
3683   auto WriteRange = [&](ConstantRange Range) {
3684     Range = Range.sextOrTrunc(FunctionSummary::ParamAccess::RangeWidth);
3685     assert(Range.getLower().getNumWords() == 1);
3686     assert(Range.getUpper().getNumWords() == 1);
3687     emitSignedInt64(Record, *Range.getLower().getRawData());
3688     emitSignedInt64(Record, *Range.getUpper().getRawData());
3689   };
3690 
3691   if (!FS->paramAccesses().empty()) {
3692     Record.clear();
3693     for (auto &Arg : FS->paramAccesses()) {
3694       size_t UndoSize = Record.size();
3695       Record.push_back(Arg.ParamNo);
3696       WriteRange(Arg.Use);
3697       Record.push_back(Arg.Calls.size());
3698       for (auto &Call : Arg.Calls) {
3699         Record.push_back(Call.ParamNo);
3700         Optional<unsigned> ValueID = GetValueID(Call.Callee);
3701         if (!ValueID) {
3702           // If ValueID is unknown we can't drop just this call, we must drop
3703           // entire parameter.
3704           Record.resize(UndoSize);
3705           break;
3706         }
3707         Record.push_back(*ValueID);
3708         WriteRange(Call.Offsets);
3709       }
3710     }
3711     if (!Record.empty())
3712       Stream.EmitRecord(bitc::FS_PARAM_ACCESS, Record);
3713   }
3714 }
3715 
3716 /// Collect type IDs from type tests used by function.
3717 static void
3718 getReferencedTypeIds(FunctionSummary *FS,
3719                      std::set<GlobalValue::GUID> &ReferencedTypeIds) {
3720   if (!FS->type_tests().empty())
3721     for (auto &TT : FS->type_tests())
3722       ReferencedTypeIds.insert(TT);
3723 
3724   auto GetReferencedTypesFromVFuncIdVec =
3725       [&](ArrayRef<FunctionSummary::VFuncId> VFs) {
3726         for (auto &VF : VFs)
3727           ReferencedTypeIds.insert(VF.GUID);
3728       };
3729 
3730   GetReferencedTypesFromVFuncIdVec(FS->type_test_assume_vcalls());
3731   GetReferencedTypesFromVFuncIdVec(FS->type_checked_load_vcalls());
3732 
3733   auto GetReferencedTypesFromConstVCallVec =
3734       [&](ArrayRef<FunctionSummary::ConstVCall> VCs) {
3735         for (auto &VC : VCs)
3736           ReferencedTypeIds.insert(VC.VFunc.GUID);
3737       };
3738 
3739   GetReferencedTypesFromConstVCallVec(FS->type_test_assume_const_vcalls());
3740   GetReferencedTypesFromConstVCallVec(FS->type_checked_load_const_vcalls());
3741 }
3742 
3743 static void writeWholeProgramDevirtResolutionByArg(
3744     SmallVector<uint64_t, 64> &NameVals, const std::vector<uint64_t> &args,
3745     const WholeProgramDevirtResolution::ByArg &ByArg) {
3746   NameVals.push_back(args.size());
3747   llvm::append_range(NameVals, args);
3748 
3749   NameVals.push_back(ByArg.TheKind);
3750   NameVals.push_back(ByArg.Info);
3751   NameVals.push_back(ByArg.Byte);
3752   NameVals.push_back(ByArg.Bit);
3753 }
3754 
3755 static void writeWholeProgramDevirtResolution(
3756     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3757     uint64_t Id, const WholeProgramDevirtResolution &Wpd) {
3758   NameVals.push_back(Id);
3759 
3760   NameVals.push_back(Wpd.TheKind);
3761   NameVals.push_back(StrtabBuilder.add(Wpd.SingleImplName));
3762   NameVals.push_back(Wpd.SingleImplName.size());
3763 
3764   NameVals.push_back(Wpd.ResByArg.size());
3765   for (auto &A : Wpd.ResByArg)
3766     writeWholeProgramDevirtResolutionByArg(NameVals, A.first, A.second);
3767 }
3768 
3769 static void writeTypeIdSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
3770                                      StringTableBuilder &StrtabBuilder,
3771                                      const std::string &Id,
3772                                      const TypeIdSummary &Summary) {
3773   NameVals.push_back(StrtabBuilder.add(Id));
3774   NameVals.push_back(Id.size());
3775 
3776   NameVals.push_back(Summary.TTRes.TheKind);
3777   NameVals.push_back(Summary.TTRes.SizeM1BitWidth);
3778   NameVals.push_back(Summary.TTRes.AlignLog2);
3779   NameVals.push_back(Summary.TTRes.SizeM1);
3780   NameVals.push_back(Summary.TTRes.BitMask);
3781   NameVals.push_back(Summary.TTRes.InlineBits);
3782 
3783   for (auto &W : Summary.WPDRes)
3784     writeWholeProgramDevirtResolution(NameVals, StrtabBuilder, W.first,
3785                                       W.second);
3786 }
3787 
3788 static void writeTypeIdCompatibleVtableSummaryRecord(
3789     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3790     const std::string &Id, const TypeIdCompatibleVtableInfo &Summary,
3791     ValueEnumerator &VE) {
3792   NameVals.push_back(StrtabBuilder.add(Id));
3793   NameVals.push_back(Id.size());
3794 
3795   for (auto &P : Summary) {
3796     NameVals.push_back(P.AddressPointOffset);
3797     NameVals.push_back(VE.getValueID(P.VTableVI.getValue()));
3798   }
3799 }
3800 
3801 // Helper to emit a single function summary record.
3802 void ModuleBitcodeWriterBase::writePerModuleFunctionSummaryRecord(
3803     SmallVector<uint64_t, 64> &NameVals, GlobalValueSummary *Summary,
3804     unsigned ValueID, unsigned FSCallsAbbrev, unsigned FSCallsProfileAbbrev,
3805     const Function &F) {
3806   NameVals.push_back(ValueID);
3807 
3808   FunctionSummary *FS = cast<FunctionSummary>(Summary);
3809 
3810   writeFunctionTypeMetadataRecords(
3811       Stream, FS, [&](const ValueInfo &VI) -> Optional<unsigned> {
3812         return {VE.getValueID(VI.getValue())};
3813       });
3814 
3815   auto SpecialRefCnts = FS->specialRefCounts();
3816   NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
3817   NameVals.push_back(FS->instCount());
3818   NameVals.push_back(getEncodedFFlags(FS->fflags()));
3819   NameVals.push_back(FS->refs().size());
3820   NameVals.push_back(SpecialRefCnts.first);  // rorefcnt
3821   NameVals.push_back(SpecialRefCnts.second); // worefcnt
3822 
3823   for (auto &RI : FS->refs())
3824     NameVals.push_back(VE.getValueID(RI.getValue()));
3825 
3826   bool HasProfileData =
3827       F.hasProfileData() || ForceSummaryEdgesCold != FunctionSummary::FSHT_None;
3828   for (auto &ECI : FS->calls()) {
3829     NameVals.push_back(getValueId(ECI.first));
3830     if (HasProfileData)
3831       NameVals.push_back(static_cast<uint8_t>(ECI.second.Hotness));
3832     else if (WriteRelBFToSummary)
3833       NameVals.push_back(ECI.second.RelBlockFreq);
3834   }
3835 
3836   unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
3837   unsigned Code =
3838       (HasProfileData ? bitc::FS_PERMODULE_PROFILE
3839                       : (WriteRelBFToSummary ? bitc::FS_PERMODULE_RELBF
3840                                              : bitc::FS_PERMODULE));
3841 
3842   // Emit the finished record.
3843   Stream.EmitRecord(Code, NameVals, FSAbbrev);
3844   NameVals.clear();
3845 }
3846 
3847 // Collect the global value references in the given variable's initializer,
3848 // and emit them in a summary record.
3849 void ModuleBitcodeWriterBase::writeModuleLevelReferences(
3850     const GlobalVariable &V, SmallVector<uint64_t, 64> &NameVals,
3851     unsigned FSModRefsAbbrev, unsigned FSModVTableRefsAbbrev) {
3852   auto VI = Index->getValueInfo(V.getGUID());
3853   if (!VI || VI.getSummaryList().empty()) {
3854     // Only declarations should not have a summary (a declaration might however
3855     // have a summary if the def was in module level asm).
3856     assert(V.isDeclaration());
3857     return;
3858   }
3859   auto *Summary = VI.getSummaryList()[0].get();
3860   NameVals.push_back(VE.getValueID(&V));
3861   GlobalVarSummary *VS = cast<GlobalVarSummary>(Summary);
3862   NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
3863   NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
3864 
3865   auto VTableFuncs = VS->vTableFuncs();
3866   if (!VTableFuncs.empty())
3867     NameVals.push_back(VS->refs().size());
3868 
3869   unsigned SizeBeforeRefs = NameVals.size();
3870   for (auto &RI : VS->refs())
3871     NameVals.push_back(VE.getValueID(RI.getValue()));
3872   // Sort the refs for determinism output, the vector returned by FS->refs() has
3873   // been initialized from a DenseSet.
3874   llvm::sort(drop_begin(NameVals, SizeBeforeRefs));
3875 
3876   if (VTableFuncs.empty())
3877     Stream.EmitRecord(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS, NameVals,
3878                       FSModRefsAbbrev);
3879   else {
3880     // VTableFuncs pairs should already be sorted by offset.
3881     for (auto &P : VTableFuncs) {
3882       NameVals.push_back(VE.getValueID(P.FuncVI.getValue()));
3883       NameVals.push_back(P.VTableOffset);
3884     }
3885 
3886     Stream.EmitRecord(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS, NameVals,
3887                       FSModVTableRefsAbbrev);
3888   }
3889   NameVals.clear();
3890 }
3891 
3892 /// Emit the per-module summary section alongside the rest of
3893 /// the module's bitcode.
3894 void ModuleBitcodeWriterBase::writePerModuleGlobalValueSummary() {
3895   // By default we compile with ThinLTO if the module has a summary, but the
3896   // client can request full LTO with a module flag.
3897   bool IsThinLTO = true;
3898   if (auto *MD =
3899           mdconst::extract_or_null<ConstantInt>(M.getModuleFlag("ThinLTO")))
3900     IsThinLTO = MD->getZExtValue();
3901   Stream.EnterSubblock(IsThinLTO ? bitc::GLOBALVAL_SUMMARY_BLOCK_ID
3902                                  : bitc::FULL_LTO_GLOBALVAL_SUMMARY_BLOCK_ID,
3903                        4);
3904 
3905   Stream.EmitRecord(
3906       bitc::FS_VERSION,
3907       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
3908 
3909   // Write the index flags.
3910   uint64_t Flags = 0;
3911   // Bits 1-3 are set only in the combined index, skip them.
3912   if (Index->enableSplitLTOUnit())
3913     Flags |= 0x8;
3914   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Flags});
3915 
3916   if (Index->begin() == Index->end()) {
3917     Stream.ExitBlock();
3918     return;
3919   }
3920 
3921   for (const auto &GVI : valueIds()) {
3922     Stream.EmitRecord(bitc::FS_VALUE_GUID,
3923                       ArrayRef<uint64_t>{GVI.second, GVI.first});
3924   }
3925 
3926   // Abbrev for FS_PERMODULE_PROFILE.
3927   auto Abbv = std::make_shared<BitCodeAbbrev>();
3928   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_PROFILE));
3929   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3930   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3931   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3932   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3933   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3934   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
3935   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
3936   // numrefs x valueid, n x (valueid, hotness)
3937   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3938   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3939   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3940 
3941   // Abbrev for FS_PERMODULE or FS_PERMODULE_RELBF.
3942   Abbv = std::make_shared<BitCodeAbbrev>();
3943   if (WriteRelBFToSummary)
3944     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_RELBF));
3945   else
3946     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE));
3947   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3948   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3949   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3950   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3951   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3952   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
3953   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
3954   // numrefs x valueid, n x (valueid [, rel_block_freq])
3955   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3956   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3957   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3958 
3959   // Abbrev for FS_PERMODULE_GLOBALVAR_INIT_REFS.
3960   Abbv = std::make_shared<BitCodeAbbrev>();
3961   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS));
3962   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
3963   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
3964   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));  // valueids
3965   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3966   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3967 
3968   // Abbrev for FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS.
3969   Abbv = std::make_shared<BitCodeAbbrev>();
3970   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS));
3971   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
3972   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
3973   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numrefs
3974   // numrefs x valueid, n x (valueid , offset)
3975   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3976   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3977   unsigned FSModVTableRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3978 
3979   // Abbrev for FS_ALIAS.
3980   Abbv = std::make_shared<BitCodeAbbrev>();
3981   Abbv->Add(BitCodeAbbrevOp(bitc::FS_ALIAS));
3982   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3983   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3984   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3985   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3986 
3987   // Abbrev for FS_TYPE_ID_METADATA
3988   Abbv = std::make_shared<BitCodeAbbrev>();
3989   Abbv->Add(BitCodeAbbrevOp(bitc::FS_TYPE_ID_METADATA));
3990   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid strtab index
3991   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid length
3992   // n x (valueid , offset)
3993   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3994   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3995   unsigned TypeIdCompatibleVtableAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3996 
3997   SmallVector<uint64_t, 64> NameVals;
3998   // Iterate over the list of functions instead of the Index to
3999   // ensure the ordering is stable.
4000   for (const Function &F : M) {
4001     // Summary emission does not support anonymous functions, they have to
4002     // renamed using the anonymous function renaming pass.
4003     if (!F.hasName())
4004       report_fatal_error("Unexpected anonymous function when writing summary");
4005 
4006     ValueInfo VI = Index->getValueInfo(F.getGUID());
4007     if (!VI || VI.getSummaryList().empty()) {
4008       // Only declarations should not have a summary (a declaration might
4009       // however have a summary if the def was in module level asm).
4010       assert(F.isDeclaration());
4011       continue;
4012     }
4013     auto *Summary = VI.getSummaryList()[0].get();
4014     writePerModuleFunctionSummaryRecord(NameVals, Summary, VE.getValueID(&F),
4015                                         FSCallsAbbrev, FSCallsProfileAbbrev, F);
4016   }
4017 
4018   // Capture references from GlobalVariable initializers, which are outside
4019   // of a function scope.
4020   for (const GlobalVariable &G : M.globals())
4021     writeModuleLevelReferences(G, NameVals, FSModRefsAbbrev,
4022                                FSModVTableRefsAbbrev);
4023 
4024   for (const GlobalAlias &A : M.aliases()) {
4025     auto *Aliasee = A.getBaseObject();
4026     if (!Aliasee->hasName())
4027       // Nameless function don't have an entry in the summary, skip it.
4028       continue;
4029     auto AliasId = VE.getValueID(&A);
4030     auto AliaseeId = VE.getValueID(Aliasee);
4031     NameVals.push_back(AliasId);
4032     auto *Summary = Index->getGlobalValueSummary(A);
4033     AliasSummary *AS = cast<AliasSummary>(Summary);
4034     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
4035     NameVals.push_back(AliaseeId);
4036     Stream.EmitRecord(bitc::FS_ALIAS, NameVals, FSAliasAbbrev);
4037     NameVals.clear();
4038   }
4039 
4040   for (auto &S : Index->typeIdCompatibleVtableMap()) {
4041     writeTypeIdCompatibleVtableSummaryRecord(NameVals, StrtabBuilder, S.first,
4042                                              S.second, VE);
4043     Stream.EmitRecord(bitc::FS_TYPE_ID_METADATA, NameVals,
4044                       TypeIdCompatibleVtableAbbrev);
4045     NameVals.clear();
4046   }
4047 
4048   Stream.EmitRecord(bitc::FS_BLOCK_COUNT,
4049                     ArrayRef<uint64_t>{Index->getBlockCount()});
4050 
4051   Stream.ExitBlock();
4052 }
4053 
4054 /// Emit the combined summary section into the combined index file.
4055 void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
4056   Stream.EnterSubblock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID, 3);
4057   Stream.EmitRecord(
4058       bitc::FS_VERSION,
4059       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
4060 
4061   // Write the index flags.
4062   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Index.getFlags()});
4063 
4064   for (const auto &GVI : valueIds()) {
4065     Stream.EmitRecord(bitc::FS_VALUE_GUID,
4066                       ArrayRef<uint64_t>{GVI.second, GVI.first});
4067   }
4068 
4069   // Abbrev for FS_COMBINED.
4070   auto Abbv = std::make_shared<BitCodeAbbrev>();
4071   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED));
4072   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4073   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4074   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4075   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4076   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4077   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
4078   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4079   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4080   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4081   // numrefs x valueid, n x (valueid)
4082   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4083   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4084   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4085 
4086   // Abbrev for FS_COMBINED_PROFILE.
4087   Abbv = std::make_shared<BitCodeAbbrev>();
4088   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_PROFILE));
4089   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4090   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4091   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4092   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4093   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4094   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
4095   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4096   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4097   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4098   // numrefs x valueid, n x (valueid, hotness)
4099   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4100   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4101   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4102 
4103   // Abbrev for FS_COMBINED_GLOBALVAR_INIT_REFS.
4104   Abbv = std::make_shared<BitCodeAbbrev>();
4105   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS));
4106   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4107   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4108   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4109   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));    // valueids
4110   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4111   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4112 
4113   // Abbrev for FS_COMBINED_ALIAS.
4114   Abbv = std::make_shared<BitCodeAbbrev>();
4115   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_ALIAS));
4116   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4117   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4118   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4119   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4120   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4121 
4122   // The aliases are emitted as a post-pass, and will point to the value
4123   // id of the aliasee. Save them in a vector for post-processing.
4124   SmallVector<AliasSummary *, 64> Aliases;
4125 
4126   // Save the value id for each summary for alias emission.
4127   DenseMap<const GlobalValueSummary *, unsigned> SummaryToValueIdMap;
4128 
4129   SmallVector<uint64_t, 64> NameVals;
4130 
4131   // Set that will be populated during call to writeFunctionTypeMetadataRecords
4132   // with the type ids referenced by this index file.
4133   std::set<GlobalValue::GUID> ReferencedTypeIds;
4134 
4135   // For local linkage, we also emit the original name separately
4136   // immediately after the record.
4137   auto MaybeEmitOriginalName = [&](GlobalValueSummary &S) {
4138     if (!GlobalValue::isLocalLinkage(S.linkage()))
4139       return;
4140     NameVals.push_back(S.getOriginalName());
4141     Stream.EmitRecord(bitc::FS_COMBINED_ORIGINAL_NAME, NameVals);
4142     NameVals.clear();
4143   };
4144 
4145   std::set<GlobalValue::GUID> DefOrUseGUIDs;
4146   forEachSummary([&](GVInfo I, bool IsAliasee) {
4147     GlobalValueSummary *S = I.second;
4148     assert(S);
4149     DefOrUseGUIDs.insert(I.first);
4150     for (const ValueInfo &VI : S->refs())
4151       DefOrUseGUIDs.insert(VI.getGUID());
4152 
4153     auto ValueId = getValueId(I.first);
4154     assert(ValueId);
4155     SummaryToValueIdMap[S] = *ValueId;
4156 
4157     // If this is invoked for an aliasee, we want to record the above
4158     // mapping, but then not emit a summary entry (if the aliasee is
4159     // to be imported, we will invoke this separately with IsAliasee=false).
4160     if (IsAliasee)
4161       return;
4162 
4163     if (auto *AS = dyn_cast<AliasSummary>(S)) {
4164       // Will process aliases as a post-pass because the reader wants all
4165       // global to be loaded first.
4166       Aliases.push_back(AS);
4167       return;
4168     }
4169 
4170     if (auto *VS = dyn_cast<GlobalVarSummary>(S)) {
4171       NameVals.push_back(*ValueId);
4172       NameVals.push_back(Index.getModuleId(VS->modulePath()));
4173       NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
4174       NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
4175       for (auto &RI : VS->refs()) {
4176         auto RefValueId = getValueId(RI.getGUID());
4177         if (!RefValueId)
4178           continue;
4179         NameVals.push_back(*RefValueId);
4180       }
4181 
4182       // Emit the finished record.
4183       Stream.EmitRecord(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS, NameVals,
4184                         FSModRefsAbbrev);
4185       NameVals.clear();
4186       MaybeEmitOriginalName(*S);
4187       return;
4188     }
4189 
4190     auto GetValueId = [&](const ValueInfo &VI) -> Optional<unsigned> {
4191       GlobalValue::GUID GUID = VI.getGUID();
4192       Optional<unsigned> CallValueId = getValueId(GUID);
4193       if (CallValueId)
4194         return CallValueId;
4195       // For SamplePGO, the indirect call targets for local functions will
4196       // have its original name annotated in profile. We try to find the
4197       // corresponding PGOFuncName as the GUID.
4198       GUID = Index.getGUIDFromOriginalID(GUID);
4199       if (!GUID)
4200         return None;
4201       CallValueId = getValueId(GUID);
4202       if (!CallValueId)
4203         return None;
4204       // The mapping from OriginalId to GUID may return a GUID
4205       // that corresponds to a static variable. Filter it out here.
4206       // This can happen when
4207       // 1) There is a call to a library function which does not have
4208       // a CallValidId;
4209       // 2) There is a static variable with the  OriginalGUID identical
4210       // to the GUID of the library function in 1);
4211       // When this happens, the logic for SamplePGO kicks in and
4212       // the static variable in 2) will be found, which needs to be
4213       // filtered out.
4214       auto *GVSum = Index.getGlobalValueSummary(GUID, false);
4215       if (GVSum && GVSum->getSummaryKind() == GlobalValueSummary::GlobalVarKind)
4216         return None;
4217       return CallValueId;
4218     };
4219 
4220     auto *FS = cast<FunctionSummary>(S);
4221     writeFunctionTypeMetadataRecords(Stream, FS, GetValueId);
4222     getReferencedTypeIds(FS, ReferencedTypeIds);
4223 
4224     NameVals.push_back(*ValueId);
4225     NameVals.push_back(Index.getModuleId(FS->modulePath()));
4226     NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
4227     NameVals.push_back(FS->instCount());
4228     NameVals.push_back(getEncodedFFlags(FS->fflags()));
4229     NameVals.push_back(FS->entryCount());
4230 
4231     // Fill in below
4232     NameVals.push_back(0); // numrefs
4233     NameVals.push_back(0); // rorefcnt
4234     NameVals.push_back(0); // worefcnt
4235 
4236     unsigned Count = 0, RORefCnt = 0, WORefCnt = 0;
4237     for (auto &RI : FS->refs()) {
4238       auto RefValueId = getValueId(RI.getGUID());
4239       if (!RefValueId)
4240         continue;
4241       NameVals.push_back(*RefValueId);
4242       if (RI.isReadOnly())
4243         RORefCnt++;
4244       else if (RI.isWriteOnly())
4245         WORefCnt++;
4246       Count++;
4247     }
4248     NameVals[6] = Count;
4249     NameVals[7] = RORefCnt;
4250     NameVals[8] = WORefCnt;
4251 
4252     bool HasProfileData = false;
4253     for (auto &EI : FS->calls()) {
4254       HasProfileData |=
4255           EI.second.getHotness() != CalleeInfo::HotnessType::Unknown;
4256       if (HasProfileData)
4257         break;
4258     }
4259 
4260     for (auto &EI : FS->calls()) {
4261       // If this GUID doesn't have a value id, it doesn't have a function
4262       // summary and we don't need to record any calls to it.
4263       Optional<unsigned> CallValueId = GetValueId(EI.first);
4264       if (!CallValueId)
4265         continue;
4266       NameVals.push_back(*CallValueId);
4267       if (HasProfileData)
4268         NameVals.push_back(static_cast<uint8_t>(EI.second.Hotness));
4269     }
4270 
4271     unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
4272     unsigned Code =
4273         (HasProfileData ? bitc::FS_COMBINED_PROFILE : bitc::FS_COMBINED);
4274 
4275     // Emit the finished record.
4276     Stream.EmitRecord(Code, NameVals, FSAbbrev);
4277     NameVals.clear();
4278     MaybeEmitOriginalName(*S);
4279   });
4280 
4281   for (auto *AS : Aliases) {
4282     auto AliasValueId = SummaryToValueIdMap[AS];
4283     assert(AliasValueId);
4284     NameVals.push_back(AliasValueId);
4285     NameVals.push_back(Index.getModuleId(AS->modulePath()));
4286     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
4287     auto AliaseeValueId = SummaryToValueIdMap[&AS->getAliasee()];
4288     assert(AliaseeValueId);
4289     NameVals.push_back(AliaseeValueId);
4290 
4291     // Emit the finished record.
4292     Stream.EmitRecord(bitc::FS_COMBINED_ALIAS, NameVals, FSAliasAbbrev);
4293     NameVals.clear();
4294     MaybeEmitOriginalName(*AS);
4295 
4296     if (auto *FS = dyn_cast<FunctionSummary>(&AS->getAliasee()))
4297       getReferencedTypeIds(FS, ReferencedTypeIds);
4298   }
4299 
4300   if (!Index.cfiFunctionDefs().empty()) {
4301     for (auto &S : Index.cfiFunctionDefs()) {
4302       if (DefOrUseGUIDs.count(
4303               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4304         NameVals.push_back(StrtabBuilder.add(S));
4305         NameVals.push_back(S.size());
4306       }
4307     }
4308     if (!NameVals.empty()) {
4309       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DEFS, NameVals);
4310       NameVals.clear();
4311     }
4312   }
4313 
4314   if (!Index.cfiFunctionDecls().empty()) {
4315     for (auto &S : Index.cfiFunctionDecls()) {
4316       if (DefOrUseGUIDs.count(
4317               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4318         NameVals.push_back(StrtabBuilder.add(S));
4319         NameVals.push_back(S.size());
4320       }
4321     }
4322     if (!NameVals.empty()) {
4323       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DECLS, NameVals);
4324       NameVals.clear();
4325     }
4326   }
4327 
4328   // Walk the GUIDs that were referenced, and write the
4329   // corresponding type id records.
4330   for (auto &T : ReferencedTypeIds) {
4331     auto TidIter = Index.typeIds().equal_range(T);
4332     for (auto It = TidIter.first; It != TidIter.second; ++It) {
4333       writeTypeIdSummaryRecord(NameVals, StrtabBuilder, It->second.first,
4334                                It->second.second);
4335       Stream.EmitRecord(bitc::FS_TYPE_ID, NameVals);
4336       NameVals.clear();
4337     }
4338   }
4339 
4340   Stream.EmitRecord(bitc::FS_BLOCK_COUNT,
4341                     ArrayRef<uint64_t>{Index.getBlockCount()});
4342 
4343   Stream.ExitBlock();
4344 }
4345 
4346 /// Create the "IDENTIFICATION_BLOCK_ID" containing a single string with the
4347 /// current llvm version, and a record for the epoch number.
4348 static void writeIdentificationBlock(BitstreamWriter &Stream) {
4349   Stream.EnterSubblock(bitc::IDENTIFICATION_BLOCK_ID, 5);
4350 
4351   // Write the "user readable" string identifying the bitcode producer
4352   auto Abbv = std::make_shared<BitCodeAbbrev>();
4353   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_STRING));
4354   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4355   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
4356   auto StringAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4357   writeStringRecord(Stream, bitc::IDENTIFICATION_CODE_STRING,
4358                     "LLVM" LLVM_VERSION_STRING, StringAbbrev);
4359 
4360   // Write the epoch version
4361   Abbv = std::make_shared<BitCodeAbbrev>();
4362   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_EPOCH));
4363   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
4364   auto EpochAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4365   constexpr std::array<unsigned, 1> Vals = {{bitc::BITCODE_CURRENT_EPOCH}};
4366   Stream.EmitRecord(bitc::IDENTIFICATION_CODE_EPOCH, Vals, EpochAbbrev);
4367   Stream.ExitBlock();
4368 }
4369 
4370 void ModuleBitcodeWriter::writeModuleHash(size_t BlockStartPos) {
4371   // Emit the module's hash.
4372   // MODULE_CODE_HASH: [5*i32]
4373   if (GenerateHash) {
4374     uint32_t Vals[5];
4375     Hasher.update(ArrayRef<uint8_t>((const uint8_t *)&(Buffer)[BlockStartPos],
4376                                     Buffer.size() - BlockStartPos));
4377     StringRef Hash = Hasher.result();
4378     for (int Pos = 0; Pos < 20; Pos += 4) {
4379       Vals[Pos / 4] = support::endian::read32be(Hash.data() + Pos);
4380     }
4381 
4382     // Emit the finished record.
4383     Stream.EmitRecord(bitc::MODULE_CODE_HASH, Vals);
4384 
4385     if (ModHash)
4386       // Save the written hash value.
4387       llvm::copy(Vals, std::begin(*ModHash));
4388   }
4389 }
4390 
4391 void ModuleBitcodeWriter::write() {
4392   writeIdentificationBlock(Stream);
4393 
4394   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4395   size_t BlockStartPos = Buffer.size();
4396 
4397   writeModuleVersion();
4398 
4399   // Emit blockinfo, which defines the standard abbreviations etc.
4400   writeBlockInfo();
4401 
4402   // Emit information describing all of the types in the module.
4403   writeTypeTable();
4404 
4405   // Emit information about attribute groups.
4406   writeAttributeGroupTable();
4407 
4408   // Emit information about parameter attributes.
4409   writeAttributeTable();
4410 
4411   writeComdats();
4412 
4413   // Emit top-level description of module, including target triple, inline asm,
4414   // descriptors for global variables, and function prototype info.
4415   writeModuleInfo();
4416 
4417   // Emit constants.
4418   writeModuleConstants();
4419 
4420   // Emit metadata kind names.
4421   writeModuleMetadataKinds();
4422 
4423   // Emit metadata.
4424   writeModuleMetadata();
4425 
4426   // Emit module-level use-lists.
4427   if (VE.shouldPreserveUseListOrder())
4428     writeUseListBlock(nullptr);
4429 
4430   writeOperandBundleTags();
4431   writeSyncScopeNames();
4432 
4433   // Emit function bodies.
4434   DenseMap<const Function *, uint64_t> FunctionToBitcodeIndex;
4435   for (Module::const_iterator F = M.begin(), E = M.end(); F != E; ++F)
4436     if (!F->isDeclaration())
4437       writeFunction(*F, FunctionToBitcodeIndex);
4438 
4439   // Need to write after the above call to WriteFunction which populates
4440   // the summary information in the index.
4441   if (Index)
4442     writePerModuleGlobalValueSummary();
4443 
4444   writeGlobalValueSymbolTable(FunctionToBitcodeIndex);
4445 
4446   writeModuleHash(BlockStartPos);
4447 
4448   Stream.ExitBlock();
4449 }
4450 
4451 static void writeInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
4452                                uint32_t &Position) {
4453   support::endian::write32le(&Buffer[Position], Value);
4454   Position += 4;
4455 }
4456 
4457 /// If generating a bc file on darwin, we have to emit a
4458 /// header and trailer to make it compatible with the system archiver.  To do
4459 /// this we emit the following header, and then emit a trailer that pads the
4460 /// file out to be a multiple of 16 bytes.
4461 ///
4462 /// struct bc_header {
4463 ///   uint32_t Magic;         // 0x0B17C0DE
4464 ///   uint32_t Version;       // Version, currently always 0.
4465 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
4466 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
4467 ///   uint32_t CPUType;       // CPU specifier.
4468 ///   ... potentially more later ...
4469 /// };
4470 static void emitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
4471                                          const Triple &TT) {
4472   unsigned CPUType = ~0U;
4473 
4474   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
4475   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
4476   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
4477   // specific constants here because they are implicitly part of the Darwin ABI.
4478   enum {
4479     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
4480     DARWIN_CPU_TYPE_X86        = 7,
4481     DARWIN_CPU_TYPE_ARM        = 12,
4482     DARWIN_CPU_TYPE_POWERPC    = 18
4483   };
4484 
4485   Triple::ArchType Arch = TT.getArch();
4486   if (Arch == Triple::x86_64)
4487     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
4488   else if (Arch == Triple::x86)
4489     CPUType = DARWIN_CPU_TYPE_X86;
4490   else if (Arch == Triple::ppc)
4491     CPUType = DARWIN_CPU_TYPE_POWERPC;
4492   else if (Arch == Triple::ppc64)
4493     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
4494   else if (Arch == Triple::arm || Arch == Triple::thumb)
4495     CPUType = DARWIN_CPU_TYPE_ARM;
4496 
4497   // Traditional Bitcode starts after header.
4498   assert(Buffer.size() >= BWH_HeaderSize &&
4499          "Expected header size to be reserved");
4500   unsigned BCOffset = BWH_HeaderSize;
4501   unsigned BCSize = Buffer.size() - BWH_HeaderSize;
4502 
4503   // Write the magic and version.
4504   unsigned Position = 0;
4505   writeInt32ToBuffer(0x0B17C0DE, Buffer, Position);
4506   writeInt32ToBuffer(0, Buffer, Position); // Version.
4507   writeInt32ToBuffer(BCOffset, Buffer, Position);
4508   writeInt32ToBuffer(BCSize, Buffer, Position);
4509   writeInt32ToBuffer(CPUType, Buffer, Position);
4510 
4511   // If the file is not a multiple of 16 bytes, insert dummy padding.
4512   while (Buffer.size() & 15)
4513     Buffer.push_back(0);
4514 }
4515 
4516 /// Helper to write the header common to all bitcode files.
4517 static void writeBitcodeHeader(BitstreamWriter &Stream) {
4518   // Emit the file header.
4519   Stream.Emit((unsigned)'B', 8);
4520   Stream.Emit((unsigned)'C', 8);
4521   Stream.Emit(0x0, 4);
4522   Stream.Emit(0xC, 4);
4523   Stream.Emit(0xE, 4);
4524   Stream.Emit(0xD, 4);
4525 }
4526 
4527 BitcodeWriter::BitcodeWriter(SmallVectorImpl<char> &Buffer, raw_fd_stream *FS)
4528     : Buffer(Buffer), Stream(new BitstreamWriter(Buffer, FS, FlushThreshold)) {
4529   writeBitcodeHeader(*Stream);
4530 }
4531 
4532 BitcodeWriter::~BitcodeWriter() { assert(WroteStrtab); }
4533 
4534 void BitcodeWriter::writeBlob(unsigned Block, unsigned Record, StringRef Blob) {
4535   Stream->EnterSubblock(Block, 3);
4536 
4537   auto Abbv = std::make_shared<BitCodeAbbrev>();
4538   Abbv->Add(BitCodeAbbrevOp(Record));
4539   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
4540   auto AbbrevNo = Stream->EmitAbbrev(std::move(Abbv));
4541 
4542   Stream->EmitRecordWithBlob(AbbrevNo, ArrayRef<uint64_t>{Record}, Blob);
4543 
4544   Stream->ExitBlock();
4545 }
4546 
4547 void BitcodeWriter::writeSymtab() {
4548   assert(!WroteStrtab && !WroteSymtab);
4549 
4550   // If any module has module-level inline asm, we will require a registered asm
4551   // parser for the target so that we can create an accurate symbol table for
4552   // the module.
4553   for (Module *M : Mods) {
4554     if (M->getModuleInlineAsm().empty())
4555       continue;
4556 
4557     std::string Err;
4558     const Triple TT(M->getTargetTriple());
4559     const Target *T = TargetRegistry::lookupTarget(TT.str(), Err);
4560     if (!T || !T->hasMCAsmParser())
4561       return;
4562   }
4563 
4564   WroteSymtab = true;
4565   SmallVector<char, 0> Symtab;
4566   // The irsymtab::build function may be unable to create a symbol table if the
4567   // module is malformed (e.g. it contains an invalid alias). Writing a symbol
4568   // table is not required for correctness, but we still want to be able to
4569   // write malformed modules to bitcode files, so swallow the error.
4570   if (Error E = irsymtab::build(Mods, Symtab, StrtabBuilder, Alloc)) {
4571     consumeError(std::move(E));
4572     return;
4573   }
4574 
4575   writeBlob(bitc::SYMTAB_BLOCK_ID, bitc::SYMTAB_BLOB,
4576             {Symtab.data(), Symtab.size()});
4577 }
4578 
4579 void BitcodeWriter::writeStrtab() {
4580   assert(!WroteStrtab);
4581 
4582   std::vector<char> Strtab;
4583   StrtabBuilder.finalizeInOrder();
4584   Strtab.resize(StrtabBuilder.getSize());
4585   StrtabBuilder.write((uint8_t *)Strtab.data());
4586 
4587   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB,
4588             {Strtab.data(), Strtab.size()});
4589 
4590   WroteStrtab = true;
4591 }
4592 
4593 void BitcodeWriter::copyStrtab(StringRef Strtab) {
4594   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB, Strtab);
4595   WroteStrtab = true;
4596 }
4597 
4598 void BitcodeWriter::writeModule(const Module &M,
4599                                 bool ShouldPreserveUseListOrder,
4600                                 const ModuleSummaryIndex *Index,
4601                                 bool GenerateHash, ModuleHash *ModHash) {
4602   assert(!WroteStrtab);
4603 
4604   // The Mods vector is used by irsymtab::build, which requires non-const
4605   // Modules in case it needs to materialize metadata. But the bitcode writer
4606   // requires that the module is materialized, so we can cast to non-const here,
4607   // after checking that it is in fact materialized.
4608   assert(M.isMaterialized());
4609   Mods.push_back(const_cast<Module *>(&M));
4610 
4611   ModuleBitcodeWriter ModuleWriter(M, Buffer, StrtabBuilder, *Stream,
4612                                    ShouldPreserveUseListOrder, Index,
4613                                    GenerateHash, ModHash);
4614   ModuleWriter.write();
4615 }
4616 
4617 void BitcodeWriter::writeIndex(
4618     const ModuleSummaryIndex *Index,
4619     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4620   IndexBitcodeWriter IndexWriter(*Stream, StrtabBuilder, *Index,
4621                                  ModuleToSummariesForIndex);
4622   IndexWriter.write();
4623 }
4624 
4625 /// Write the specified module to the specified output stream.
4626 void llvm::WriteBitcodeToFile(const Module &M, raw_ostream &Out,
4627                               bool ShouldPreserveUseListOrder,
4628                               const ModuleSummaryIndex *Index,
4629                               bool GenerateHash, ModuleHash *ModHash) {
4630   SmallVector<char, 0> Buffer;
4631   Buffer.reserve(256*1024);
4632 
4633   // If this is darwin or another generic macho target, reserve space for the
4634   // header.
4635   Triple TT(M.getTargetTriple());
4636   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4637     Buffer.insert(Buffer.begin(), BWH_HeaderSize, 0);
4638 
4639   BitcodeWriter Writer(Buffer, dyn_cast<raw_fd_stream>(&Out));
4640   Writer.writeModule(M, ShouldPreserveUseListOrder, Index, GenerateHash,
4641                      ModHash);
4642   Writer.writeSymtab();
4643   Writer.writeStrtab();
4644 
4645   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4646     emitDarwinBCHeaderAndTrailer(Buffer, TT);
4647 
4648   // Write the generated bitstream to "Out".
4649   if (!Buffer.empty())
4650     Out.write((char *)&Buffer.front(), Buffer.size());
4651 }
4652 
4653 void IndexBitcodeWriter::write() {
4654   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4655 
4656   writeModuleVersion();
4657 
4658   // Write the module paths in the combined index.
4659   writeModStrings();
4660 
4661   // Write the summary combined index records.
4662   writeCombinedGlobalValueSummary();
4663 
4664   Stream.ExitBlock();
4665 }
4666 
4667 // Write the specified module summary index to the given raw output stream,
4668 // where it will be written in a new bitcode block. This is used when
4669 // writing the combined index file for ThinLTO. When writing a subset of the
4670 // index for a distributed backend, provide a \p ModuleToSummariesForIndex map.
4671 void llvm::WriteIndexToFile(
4672     const ModuleSummaryIndex &Index, raw_ostream &Out,
4673     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4674   SmallVector<char, 0> Buffer;
4675   Buffer.reserve(256 * 1024);
4676 
4677   BitcodeWriter Writer(Buffer);
4678   Writer.writeIndex(&Index, ModuleToSummariesForIndex);
4679   Writer.writeStrtab();
4680 
4681   Out.write((char *)&Buffer.front(), Buffer.size());
4682 }
4683 
4684 namespace {
4685 
4686 /// Class to manage the bitcode writing for a thin link bitcode file.
4687 class ThinLinkBitcodeWriter : public ModuleBitcodeWriterBase {
4688   /// ModHash is for use in ThinLTO incremental build, generated while writing
4689   /// the module bitcode file.
4690   const ModuleHash *ModHash;
4691 
4692 public:
4693   ThinLinkBitcodeWriter(const Module &M, StringTableBuilder &StrtabBuilder,
4694                         BitstreamWriter &Stream,
4695                         const ModuleSummaryIndex &Index,
4696                         const ModuleHash &ModHash)
4697       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
4698                                 /*ShouldPreserveUseListOrder=*/false, &Index),
4699         ModHash(&ModHash) {}
4700 
4701   void write();
4702 
4703 private:
4704   void writeSimplifiedModuleInfo();
4705 };
4706 
4707 } // end anonymous namespace
4708 
4709 // This function writes a simpilified module info for thin link bitcode file.
4710 // It only contains the source file name along with the name(the offset and
4711 // size in strtab) and linkage for global values. For the global value info
4712 // entry, in order to keep linkage at offset 5, there are three zeros used
4713 // as padding.
4714 void ThinLinkBitcodeWriter::writeSimplifiedModuleInfo() {
4715   SmallVector<unsigned, 64> Vals;
4716   // Emit the module's source file name.
4717   {
4718     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
4719     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
4720     if (Bits == SE_Char6)
4721       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
4722     else if (Bits == SE_Fixed7)
4723       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
4724 
4725     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
4726     auto Abbv = std::make_shared<BitCodeAbbrev>();
4727     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
4728     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4729     Abbv->Add(AbbrevOpToUse);
4730     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4731 
4732     for (const auto P : M.getSourceFileName())
4733       Vals.push_back((unsigned char)P);
4734 
4735     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
4736     Vals.clear();
4737   }
4738 
4739   // Emit the global variable information.
4740   for (const GlobalVariable &GV : M.globals()) {
4741     // GLOBALVAR: [strtab offset, strtab size, 0, 0, 0, linkage]
4742     Vals.push_back(StrtabBuilder.add(GV.getName()));
4743     Vals.push_back(GV.getName().size());
4744     Vals.push_back(0);
4745     Vals.push_back(0);
4746     Vals.push_back(0);
4747     Vals.push_back(getEncodedLinkage(GV));
4748 
4749     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals);
4750     Vals.clear();
4751   }
4752 
4753   // Emit the function proto information.
4754   for (const Function &F : M) {
4755     // FUNCTION:  [strtab offset, strtab size, 0, 0, 0, linkage]
4756     Vals.push_back(StrtabBuilder.add(F.getName()));
4757     Vals.push_back(F.getName().size());
4758     Vals.push_back(0);
4759     Vals.push_back(0);
4760     Vals.push_back(0);
4761     Vals.push_back(getEncodedLinkage(F));
4762 
4763     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals);
4764     Vals.clear();
4765   }
4766 
4767   // Emit the alias information.
4768   for (const GlobalAlias &A : M.aliases()) {
4769     // ALIAS: [strtab offset, strtab size, 0, 0, 0, linkage]
4770     Vals.push_back(StrtabBuilder.add(A.getName()));
4771     Vals.push_back(A.getName().size());
4772     Vals.push_back(0);
4773     Vals.push_back(0);
4774     Vals.push_back(0);
4775     Vals.push_back(getEncodedLinkage(A));
4776 
4777     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals);
4778     Vals.clear();
4779   }
4780 
4781   // Emit the ifunc information.
4782   for (const GlobalIFunc &I : M.ifuncs()) {
4783     // IFUNC: [strtab offset, strtab size, 0, 0, 0, linkage]
4784     Vals.push_back(StrtabBuilder.add(I.getName()));
4785     Vals.push_back(I.getName().size());
4786     Vals.push_back(0);
4787     Vals.push_back(0);
4788     Vals.push_back(0);
4789     Vals.push_back(getEncodedLinkage(I));
4790 
4791     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
4792     Vals.clear();
4793   }
4794 }
4795 
4796 void ThinLinkBitcodeWriter::write() {
4797   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4798 
4799   writeModuleVersion();
4800 
4801   writeSimplifiedModuleInfo();
4802 
4803   writePerModuleGlobalValueSummary();
4804 
4805   // Write module hash.
4806   Stream.EmitRecord(bitc::MODULE_CODE_HASH, ArrayRef<uint32_t>(*ModHash));
4807 
4808   Stream.ExitBlock();
4809 }
4810 
4811 void BitcodeWriter::writeThinLinkBitcode(const Module &M,
4812                                          const ModuleSummaryIndex &Index,
4813                                          const ModuleHash &ModHash) {
4814   assert(!WroteStrtab);
4815 
4816   // The Mods vector is used by irsymtab::build, which requires non-const
4817   // Modules in case it needs to materialize metadata. But the bitcode writer
4818   // requires that the module is materialized, so we can cast to non-const here,
4819   // after checking that it is in fact materialized.
4820   assert(M.isMaterialized());
4821   Mods.push_back(const_cast<Module *>(&M));
4822 
4823   ThinLinkBitcodeWriter ThinLinkWriter(M, StrtabBuilder, *Stream, Index,
4824                                        ModHash);
4825   ThinLinkWriter.write();
4826 }
4827 
4828 // Write the specified thin link bitcode file to the given raw output stream,
4829 // where it will be written in a new bitcode block. This is used when
4830 // writing the per-module index file for ThinLTO.
4831 void llvm::WriteThinLinkBitcodeToFile(const Module &M, raw_ostream &Out,
4832                                       const ModuleSummaryIndex &Index,
4833                                       const ModuleHash &ModHash) {
4834   SmallVector<char, 0> Buffer;
4835   Buffer.reserve(256 * 1024);
4836 
4837   BitcodeWriter Writer(Buffer);
4838   Writer.writeThinLinkBitcode(M, Index, ModHash);
4839   Writer.writeSymtab();
4840   Writer.writeStrtab();
4841 
4842   Out.write((char *)&Buffer.front(), Buffer.size());
4843 }
4844 
4845 static const char *getSectionNameForBitcode(const Triple &T) {
4846   switch (T.getObjectFormat()) {
4847   case Triple::MachO:
4848     return "__LLVM,__bitcode";
4849   case Triple::COFF:
4850   case Triple::ELF:
4851   case Triple::Wasm:
4852   case Triple::UnknownObjectFormat:
4853     return ".llvmbc";
4854   case Triple::GOFF:
4855     llvm_unreachable("GOFF is not yet implemented");
4856     break;
4857   case Triple::XCOFF:
4858     llvm_unreachable("XCOFF is not yet implemented");
4859     break;
4860   }
4861   llvm_unreachable("Unimplemented ObjectFormatType");
4862 }
4863 
4864 static const char *getSectionNameForCommandline(const Triple &T) {
4865   switch (T.getObjectFormat()) {
4866   case Triple::MachO:
4867     return "__LLVM,__cmdline";
4868   case Triple::COFF:
4869   case Triple::ELF:
4870   case Triple::Wasm:
4871   case Triple::UnknownObjectFormat:
4872     return ".llvmcmd";
4873   case Triple::GOFF:
4874     llvm_unreachable("GOFF is not yet implemented");
4875     break;
4876   case Triple::XCOFF:
4877     llvm_unreachable("XCOFF is not yet implemented");
4878     break;
4879   }
4880   llvm_unreachable("Unimplemented ObjectFormatType");
4881 }
4882 
4883 void llvm::EmbedBitcodeInModule(llvm::Module &M, llvm::MemoryBufferRef Buf,
4884                                 bool EmbedBitcode, bool EmbedCmdline,
4885                                 const std::vector<uint8_t> &CmdArgs) {
4886   // Save llvm.compiler.used and remove it.
4887   SmallVector<Constant *, 2> UsedArray;
4888   SmallVector<GlobalValue *, 4> UsedGlobals;
4889   Type *UsedElementType = Type::getInt8Ty(M.getContext())->getPointerTo(0);
4890   GlobalVariable *Used = collectUsedGlobalVariables(M, UsedGlobals, true);
4891   for (auto *GV : UsedGlobals) {
4892     if (GV->getName() != "llvm.embedded.module" &&
4893         GV->getName() != "llvm.cmdline")
4894       UsedArray.push_back(
4895           ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
4896   }
4897   if (Used)
4898     Used->eraseFromParent();
4899 
4900   // Embed the bitcode for the llvm module.
4901   std::string Data;
4902   ArrayRef<uint8_t> ModuleData;
4903   Triple T(M.getTargetTriple());
4904 
4905   if (EmbedBitcode) {
4906     if (Buf.getBufferSize() == 0 ||
4907         !isBitcode((const unsigned char *)Buf.getBufferStart(),
4908                    (const unsigned char *)Buf.getBufferEnd())) {
4909       // If the input is LLVM Assembly, bitcode is produced by serializing
4910       // the module. Use-lists order need to be preserved in this case.
4911       llvm::raw_string_ostream OS(Data);
4912       llvm::WriteBitcodeToFile(M, OS, /* ShouldPreserveUseListOrder */ true);
4913       ModuleData =
4914           ArrayRef<uint8_t>((const uint8_t *)OS.str().data(), OS.str().size());
4915     } else
4916       // If the input is LLVM bitcode, write the input byte stream directly.
4917       ModuleData = ArrayRef<uint8_t>((const uint8_t *)Buf.getBufferStart(),
4918                                      Buf.getBufferSize());
4919   }
4920   llvm::Constant *ModuleConstant =
4921       llvm::ConstantDataArray::get(M.getContext(), ModuleData);
4922   llvm::GlobalVariable *GV = new llvm::GlobalVariable(
4923       M, ModuleConstant->getType(), true, llvm::GlobalValue::PrivateLinkage,
4924       ModuleConstant);
4925   GV->setSection(getSectionNameForBitcode(T));
4926   // Set alignment to 1 to prevent padding between two contributions from input
4927   // sections after linking.
4928   GV->setAlignment(Align(1));
4929   UsedArray.push_back(
4930       ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
4931   if (llvm::GlobalVariable *Old =
4932           M.getGlobalVariable("llvm.embedded.module", true)) {
4933     assert(Old->hasOneUse() &&
4934            "llvm.embedded.module can only be used once in llvm.compiler.used");
4935     GV->takeName(Old);
4936     Old->eraseFromParent();
4937   } else {
4938     GV->setName("llvm.embedded.module");
4939   }
4940 
4941   // Skip if only bitcode needs to be embedded.
4942   if (EmbedCmdline) {
4943     // Embed command-line options.
4944     ArrayRef<uint8_t> CmdData(const_cast<uint8_t *>(CmdArgs.data()),
4945                               CmdArgs.size());
4946     llvm::Constant *CmdConstant =
4947         llvm::ConstantDataArray::get(M.getContext(), CmdData);
4948     GV = new llvm::GlobalVariable(M, CmdConstant->getType(), true,
4949                                   llvm::GlobalValue::PrivateLinkage,
4950                                   CmdConstant);
4951     GV->setSection(getSectionNameForCommandline(T));
4952     GV->setAlignment(Align(1));
4953     UsedArray.push_back(
4954         ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
4955     if (llvm::GlobalVariable *Old = M.getGlobalVariable("llvm.cmdline", true)) {
4956       assert(Old->hasOneUse() &&
4957              "llvm.cmdline can only be used once in llvm.compiler.used");
4958       GV->takeName(Old);
4959       Old->eraseFromParent();
4960     } else {
4961       GV->setName("llvm.cmdline");
4962     }
4963   }
4964 
4965   if (UsedArray.empty())
4966     return;
4967 
4968   // Recreate llvm.compiler.used.
4969   ArrayType *ATy = ArrayType::get(UsedElementType, UsedArray.size());
4970   auto *NewUsed = new GlobalVariable(
4971       M, ATy, false, llvm::GlobalValue::AppendingLinkage,
4972       llvm::ConstantArray::get(ATy, UsedArray), "llvm.compiler.used");
4973   NewUsed->setSection("llvm.metadata");
4974 }
4975