xref: /llvm-project/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp (revision 8db981d463ee266919907f2554194d05f96f7191)
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/SetVector.h"
23 #include "llvm/ADT/SmallPtrSet.h"
24 #include "llvm/ADT/SmallString.h"
25 #include "llvm/ADT/SmallVector.h"
26 #include "llvm/ADT/StringMap.h"
27 #include "llvm/ADT/StringRef.h"
28 #include "llvm/ADT/Triple.h"
29 #include "llvm/Bitcode/BitcodeCommon.h"
30 #include "llvm/Bitcode/BitcodeReader.h"
31 #include "llvm/Bitcode/LLVMBitCodes.h"
32 #include "llvm/Bitstream/BitCodes.h"
33 #include "llvm/Bitstream/BitstreamWriter.h"
34 #include "llvm/Config/llvm-config.h"
35 #include "llvm/IR/Attributes.h"
36 #include "llvm/IR/BasicBlock.h"
37 #include "llvm/IR/Comdat.h"
38 #include "llvm/IR/Constant.h"
39 #include "llvm/IR/Constants.h"
40 #include "llvm/IR/DebugInfoMetadata.h"
41 #include "llvm/IR/DebugLoc.h"
42 #include "llvm/IR/DerivedTypes.h"
43 #include "llvm/IR/Function.h"
44 #include "llvm/IR/GlobalAlias.h"
45 #include "llvm/IR/GlobalIFunc.h"
46 #include "llvm/IR/GlobalObject.h"
47 #include "llvm/IR/GlobalValue.h"
48 #include "llvm/IR/GlobalVariable.h"
49 #include "llvm/IR/InlineAsm.h"
50 #include "llvm/IR/InstrTypes.h"
51 #include "llvm/IR/Instruction.h"
52 #include "llvm/IR/Instructions.h"
53 #include "llvm/IR/LLVMContext.h"
54 #include "llvm/IR/Metadata.h"
55 #include "llvm/IR/Module.h"
56 #include "llvm/IR/ModuleSummaryIndex.h"
57 #include "llvm/IR/Operator.h"
58 #include "llvm/IR/Type.h"
59 #include "llvm/IR/UseListOrder.h"
60 #include "llvm/IR/Value.h"
61 #include "llvm/IR/ValueSymbolTable.h"
62 #include "llvm/MC/StringTableBuilder.h"
63 #include "llvm/MC/TargetRegistry.h"
64 #include "llvm/Object/IRSymtab.h"
65 #include "llvm/Support/AtomicOrdering.h"
66 #include "llvm/Support/Casting.h"
67 #include "llvm/Support/CommandLine.h"
68 #include "llvm/Support/Endian.h"
69 #include "llvm/Support/Error.h"
70 #include "llvm/Support/ErrorHandling.h"
71 #include "llvm/Support/MathExtras.h"
72 #include "llvm/Support/SHA1.h"
73 #include "llvm/Support/raw_ostream.h"
74 #include <algorithm>
75 #include <cassert>
76 #include <cstddef>
77 #include <cstdint>
78 #include <iterator>
79 #include <map>
80 #include <memory>
81 #include <string>
82 #include <utility>
83 #include <vector>
84 
85 using namespace llvm;
86 
87 static cl::opt<unsigned>
88     IndexThreshold("bitcode-mdindex-threshold", cl::Hidden, cl::init(25),
89                    cl::desc("Number of metadatas above which we emit an index "
90                             "to enable lazy-loading"));
91 static cl::opt<uint32_t> FlushThreshold(
92     "bitcode-flush-threshold", cl::Hidden, cl::init(512),
93     cl::desc("The threshold (unit M) for flushing LLVM bitcode."));
94 
95 static cl::opt<bool> WriteRelBFToSummary(
96     "write-relbf-to-summary", cl::Hidden, cl::init(false),
97     cl::desc("Write relative block frequency to function summary "));
98 
99 extern FunctionSummary::ForceSummaryHotnessType ForceSummaryEdgesCold;
100 
101 namespace {
102 
103 /// These are manifest constants used by the bitcode writer. They do not need to
104 /// be kept in sync with the reader, but need to be consistent within this file.
105 enum {
106   // VALUE_SYMTAB_BLOCK abbrev id's.
107   VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
108   VST_ENTRY_7_ABBREV,
109   VST_ENTRY_6_ABBREV,
110   VST_BBENTRY_6_ABBREV,
111 
112   // CONSTANTS_BLOCK abbrev id's.
113   CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
114   CONSTANTS_INTEGER_ABBREV,
115   CONSTANTS_CE_CAST_Abbrev,
116   CONSTANTS_NULL_Abbrev,
117 
118   // FUNCTION_BLOCK abbrev id's.
119   FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
120   FUNCTION_INST_UNOP_ABBREV,
121   FUNCTION_INST_UNOP_FLAGS_ABBREV,
122   FUNCTION_INST_BINOP_ABBREV,
123   FUNCTION_INST_BINOP_FLAGS_ABBREV,
124   FUNCTION_INST_CAST_ABBREV,
125   FUNCTION_INST_RET_VOID_ABBREV,
126   FUNCTION_INST_RET_VAL_ABBREV,
127   FUNCTION_INST_UNREACHABLE_ABBREV,
128   FUNCTION_INST_GEP_ABBREV,
129 };
130 
131 /// Abstract class to manage the bitcode writing, subclassed for each bitcode
132 /// file type.
133 class BitcodeWriterBase {
134 protected:
135   /// The stream created and owned by the client.
136   BitstreamWriter &Stream;
137 
138   StringTableBuilder &StrtabBuilder;
139 
140 public:
141   /// Constructs a BitcodeWriterBase object that writes to the provided
142   /// \p Stream.
143   BitcodeWriterBase(BitstreamWriter &Stream, StringTableBuilder &StrtabBuilder)
144       : Stream(Stream), StrtabBuilder(StrtabBuilder) {}
145 
146 protected:
147   void writeModuleVersion();
148 };
149 
150 void BitcodeWriterBase::writeModuleVersion() {
151   // VERSION: [version#]
152   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, ArrayRef<uint64_t>{2});
153 }
154 
155 /// Base class to manage the module bitcode writing, currently subclassed for
156 /// ModuleBitcodeWriter and ThinLinkBitcodeWriter.
157 class ModuleBitcodeWriterBase : public BitcodeWriterBase {
158 protected:
159   /// The Module to write to bitcode.
160   const Module &M;
161 
162   /// Enumerates ids for all values in the module.
163   ValueEnumerator VE;
164 
165   /// Optional per-module index to write for ThinLTO.
166   const ModuleSummaryIndex *Index;
167 
168   /// Map that holds the correspondence between GUIDs in the summary index,
169   /// that came from indirect call profiles, and a value id generated by this
170   /// class to use in the VST and summary block records.
171   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
172 
173   /// Tracks the last value id recorded in the GUIDToValueMap.
174   unsigned GlobalValueId;
175 
176   /// Saves the offset of the VSTOffset record that must eventually be
177   /// backpatched with the offset of the actual VST.
178   uint64_t VSTOffsetPlaceholder = 0;
179 
180 public:
181   /// Constructs a ModuleBitcodeWriterBase object for the given Module,
182   /// writing to the provided \p Buffer.
183   ModuleBitcodeWriterBase(const Module &M, StringTableBuilder &StrtabBuilder,
184                           BitstreamWriter &Stream,
185                           bool ShouldPreserveUseListOrder,
186                           const ModuleSummaryIndex *Index)
187       : BitcodeWriterBase(Stream, StrtabBuilder), M(M),
188         VE(M, ShouldPreserveUseListOrder), Index(Index) {
189     // Assign ValueIds to any callee values in the index that came from
190     // indirect call profiles and were recorded as a GUID not a Value*
191     // (which would have been assigned an ID by the ValueEnumerator).
192     // The starting ValueId is just after the number of values in the
193     // ValueEnumerator, so that they can be emitted in the VST.
194     GlobalValueId = VE.getValues().size();
195     if (!Index)
196       return;
197     for (const auto &GUIDSummaryLists : *Index)
198       // Examine all summaries for this GUID.
199       for (auto &Summary : GUIDSummaryLists.second.SummaryList)
200         if (auto FS = dyn_cast<FunctionSummary>(Summary.get()))
201           // For each call in the function summary, see if the call
202           // is to a GUID (which means it is for an indirect call,
203           // otherwise we would have a Value for it). If so, synthesize
204           // a value id.
205           for (auto &CallEdge : FS->calls())
206             if (!CallEdge.first.haveGVs() || !CallEdge.first.getValue())
207               assignValueId(CallEdge.first.getGUID());
208   }
209 
210 protected:
211   void writePerModuleGlobalValueSummary();
212 
213 private:
214   void writePerModuleFunctionSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
215                                            GlobalValueSummary *Summary,
216                                            unsigned ValueID,
217                                            unsigned FSCallsAbbrev,
218                                            unsigned FSCallsProfileAbbrev,
219                                            const Function &F);
220   void writeModuleLevelReferences(const GlobalVariable &V,
221                                   SmallVector<uint64_t, 64> &NameVals,
222                                   unsigned FSModRefsAbbrev,
223                                   unsigned FSModVTableRefsAbbrev);
224 
225   void assignValueId(GlobalValue::GUID ValGUID) {
226     GUIDToValueIdMap[ValGUID] = ++GlobalValueId;
227   }
228 
229   unsigned getValueId(GlobalValue::GUID ValGUID) {
230     const auto &VMI = GUIDToValueIdMap.find(ValGUID);
231     // Expect that any GUID value had a value Id assigned by an
232     // earlier call to assignValueId.
233     assert(VMI != GUIDToValueIdMap.end() &&
234            "GUID does not have assigned value Id");
235     return VMI->second;
236   }
237 
238   // Helper to get the valueId for the type of value recorded in VI.
239   unsigned getValueId(ValueInfo VI) {
240     if (!VI.haveGVs() || !VI.getValue())
241       return getValueId(VI.getGUID());
242     return VE.getValueID(VI.getValue());
243   }
244 
245   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
246 };
247 
248 /// Class to manage the bitcode writing for a module.
249 class ModuleBitcodeWriter : public ModuleBitcodeWriterBase {
250   /// Pointer to the buffer allocated by caller for bitcode writing.
251   const SmallVectorImpl<char> &Buffer;
252 
253   /// True if a module hash record should be written.
254   bool GenerateHash;
255 
256   /// If non-null, when GenerateHash is true, the resulting hash is written
257   /// into ModHash.
258   ModuleHash *ModHash;
259 
260   SHA1 Hasher;
261 
262   /// The start bit of the identification block.
263   uint64_t BitcodeStartBit;
264 
265 public:
266   /// Constructs a ModuleBitcodeWriter object for the given Module,
267   /// writing to the provided \p Buffer.
268   ModuleBitcodeWriter(const Module &M, SmallVectorImpl<char> &Buffer,
269                       StringTableBuilder &StrtabBuilder,
270                       BitstreamWriter &Stream, bool ShouldPreserveUseListOrder,
271                       const ModuleSummaryIndex *Index, bool GenerateHash,
272                       ModuleHash *ModHash = nullptr)
273       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
274                                 ShouldPreserveUseListOrder, Index),
275         Buffer(Buffer), GenerateHash(GenerateHash), ModHash(ModHash),
276         BitcodeStartBit(Stream.GetCurrentBitNo()) {}
277 
278   /// Emit the current module to the bitstream.
279   void write();
280 
281 private:
282   uint64_t bitcodeStartBit() { return BitcodeStartBit; }
283 
284   size_t addToStrtab(StringRef Str);
285 
286   void writeAttributeGroupTable();
287   void writeAttributeTable();
288   void writeTypeTable();
289   void writeComdats();
290   void writeValueSymbolTableForwardDecl();
291   void writeModuleInfo();
292   void writeValueAsMetadata(const ValueAsMetadata *MD,
293                             SmallVectorImpl<uint64_t> &Record);
294   void writeMDTuple(const MDTuple *N, SmallVectorImpl<uint64_t> &Record,
295                     unsigned Abbrev);
296   unsigned createDILocationAbbrev();
297   void writeDILocation(const DILocation *N, SmallVectorImpl<uint64_t> &Record,
298                        unsigned &Abbrev);
299   unsigned createGenericDINodeAbbrev();
300   void writeGenericDINode(const GenericDINode *N,
301                           SmallVectorImpl<uint64_t> &Record, unsigned &Abbrev);
302   void writeDISubrange(const DISubrange *N, SmallVectorImpl<uint64_t> &Record,
303                        unsigned Abbrev);
304   void writeDIGenericSubrange(const DIGenericSubrange *N,
305                               SmallVectorImpl<uint64_t> &Record,
306                               unsigned Abbrev);
307   void writeDIEnumerator(const DIEnumerator *N,
308                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
309   void writeDIBasicType(const DIBasicType *N, SmallVectorImpl<uint64_t> &Record,
310                         unsigned Abbrev);
311   void writeDIStringType(const DIStringType *N,
312                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
313   void writeDIDerivedType(const DIDerivedType *N,
314                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
315   void writeDICompositeType(const DICompositeType *N,
316                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
317   void writeDISubroutineType(const DISubroutineType *N,
318                              SmallVectorImpl<uint64_t> &Record,
319                              unsigned Abbrev);
320   void writeDIFile(const DIFile *N, SmallVectorImpl<uint64_t> &Record,
321                    unsigned Abbrev);
322   void writeDICompileUnit(const DICompileUnit *N,
323                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
324   void writeDISubprogram(const DISubprogram *N,
325                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
326   void writeDILexicalBlock(const DILexicalBlock *N,
327                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
328   void writeDILexicalBlockFile(const DILexicalBlockFile *N,
329                                SmallVectorImpl<uint64_t> &Record,
330                                unsigned Abbrev);
331   void writeDICommonBlock(const DICommonBlock *N,
332                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
333   void writeDINamespace(const DINamespace *N, SmallVectorImpl<uint64_t> &Record,
334                         unsigned Abbrev);
335   void writeDIMacro(const DIMacro *N, SmallVectorImpl<uint64_t> &Record,
336                     unsigned Abbrev);
337   void writeDIMacroFile(const DIMacroFile *N, SmallVectorImpl<uint64_t> &Record,
338                         unsigned Abbrev);
339   void writeDIArgList(const DIArgList *N, SmallVectorImpl<uint64_t> &Record,
340                       unsigned Abbrev);
341   void writeDIModule(const DIModule *N, SmallVectorImpl<uint64_t> &Record,
342                      unsigned Abbrev);
343   void writeDITemplateTypeParameter(const DITemplateTypeParameter *N,
344                                     SmallVectorImpl<uint64_t> &Record,
345                                     unsigned Abbrev);
346   void writeDITemplateValueParameter(const DITemplateValueParameter *N,
347                                      SmallVectorImpl<uint64_t> &Record,
348                                      unsigned Abbrev);
349   void writeDIGlobalVariable(const DIGlobalVariable *N,
350                              SmallVectorImpl<uint64_t> &Record,
351                              unsigned Abbrev);
352   void writeDILocalVariable(const DILocalVariable *N,
353                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
354   void writeDILabel(const DILabel *N,
355                     SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
356   void writeDIExpression(const DIExpression *N,
357                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
358   void writeDIGlobalVariableExpression(const DIGlobalVariableExpression *N,
359                                        SmallVectorImpl<uint64_t> &Record,
360                                        unsigned Abbrev);
361   void writeDIObjCProperty(const DIObjCProperty *N,
362                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
363   void writeDIImportedEntity(const DIImportedEntity *N,
364                              SmallVectorImpl<uint64_t> &Record,
365                              unsigned Abbrev);
366   unsigned createNamedMetadataAbbrev();
367   void writeNamedMetadata(SmallVectorImpl<uint64_t> &Record);
368   unsigned createMetadataStringsAbbrev();
369   void writeMetadataStrings(ArrayRef<const Metadata *> Strings,
370                             SmallVectorImpl<uint64_t> &Record);
371   void writeMetadataRecords(ArrayRef<const Metadata *> MDs,
372                             SmallVectorImpl<uint64_t> &Record,
373                             std::vector<unsigned> *MDAbbrevs = nullptr,
374                             std::vector<uint64_t> *IndexPos = nullptr);
375   void writeModuleMetadata();
376   void writeFunctionMetadata(const Function &F);
377   void writeFunctionMetadataAttachment(const Function &F);
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 (char C : Str) {
602     if (AbbrevToUse && !BitCodeAbbrevOp::isChar6(C))
603       AbbrevToUse = 0;
604     Vals.push_back(C);
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::AllocAlign:
616     return bitc::ATTR_KIND_ALLOC_ALIGN;
617   case Attribute::AllocSize:
618     return bitc::ATTR_KIND_ALLOC_SIZE;
619   case Attribute::AlwaysInline:
620     return bitc::ATTR_KIND_ALWAYS_INLINE;
621   case Attribute::ArgMemOnly:
622     return bitc::ATTR_KIND_ARGMEMONLY;
623   case Attribute::Builtin:
624     return bitc::ATTR_KIND_BUILTIN;
625   case Attribute::ByVal:
626     return bitc::ATTR_KIND_BY_VAL;
627   case Attribute::Convergent:
628     return bitc::ATTR_KIND_CONVERGENT;
629   case Attribute::InAlloca:
630     return bitc::ATTR_KIND_IN_ALLOCA;
631   case Attribute::Cold:
632     return bitc::ATTR_KIND_COLD;
633   case Attribute::DisableSanitizerInstrumentation:
634     return bitc::ATTR_KIND_DISABLE_SANITIZER_INSTRUMENTATION;
635   case Attribute::Hot:
636     return bitc::ATTR_KIND_HOT;
637   case Attribute::ElementType:
638     return bitc::ATTR_KIND_ELEMENTTYPE;
639   case Attribute::InaccessibleMemOnly:
640     return bitc::ATTR_KIND_INACCESSIBLEMEM_ONLY;
641   case Attribute::InaccessibleMemOrArgMemOnly:
642     return bitc::ATTR_KIND_INACCESSIBLEMEM_OR_ARGMEMONLY;
643   case Attribute::InlineHint:
644     return bitc::ATTR_KIND_INLINE_HINT;
645   case Attribute::InReg:
646     return bitc::ATTR_KIND_IN_REG;
647   case Attribute::JumpTable:
648     return bitc::ATTR_KIND_JUMP_TABLE;
649   case Attribute::MinSize:
650     return bitc::ATTR_KIND_MIN_SIZE;
651   case Attribute::AllocatedPointer:
652     return bitc::ATTR_KIND_ALLOCATED_POINTER;
653   case Attribute::AllocKind:
654     return bitc::ATTR_KIND_ALLOC_KIND;
655   case Attribute::Naked:
656     return bitc::ATTR_KIND_NAKED;
657   case Attribute::Nest:
658     return bitc::ATTR_KIND_NEST;
659   case Attribute::NoAlias:
660     return bitc::ATTR_KIND_NO_ALIAS;
661   case Attribute::NoBuiltin:
662     return bitc::ATTR_KIND_NO_BUILTIN;
663   case Attribute::NoCallback:
664     return bitc::ATTR_KIND_NO_CALLBACK;
665   case Attribute::NoCapture:
666     return bitc::ATTR_KIND_NO_CAPTURE;
667   case Attribute::NoDuplicate:
668     return bitc::ATTR_KIND_NO_DUPLICATE;
669   case Attribute::NoFree:
670     return bitc::ATTR_KIND_NOFREE;
671   case Attribute::NoImplicitFloat:
672     return bitc::ATTR_KIND_NO_IMPLICIT_FLOAT;
673   case Attribute::NoInline:
674     return bitc::ATTR_KIND_NO_INLINE;
675   case Attribute::NoRecurse:
676     return bitc::ATTR_KIND_NO_RECURSE;
677   case Attribute::NoMerge:
678     return bitc::ATTR_KIND_NO_MERGE;
679   case Attribute::NonLazyBind:
680     return bitc::ATTR_KIND_NON_LAZY_BIND;
681   case Attribute::NonNull:
682     return bitc::ATTR_KIND_NON_NULL;
683   case Attribute::Dereferenceable:
684     return bitc::ATTR_KIND_DEREFERENCEABLE;
685   case Attribute::DereferenceableOrNull:
686     return bitc::ATTR_KIND_DEREFERENCEABLE_OR_NULL;
687   case Attribute::NoRedZone:
688     return bitc::ATTR_KIND_NO_RED_ZONE;
689   case Attribute::NoReturn:
690     return bitc::ATTR_KIND_NO_RETURN;
691   case Attribute::NoSync:
692     return bitc::ATTR_KIND_NOSYNC;
693   case Attribute::NoCfCheck:
694     return bitc::ATTR_KIND_NOCF_CHECK;
695   case Attribute::NoProfile:
696     return bitc::ATTR_KIND_NO_PROFILE;
697   case Attribute::NoUnwind:
698     return bitc::ATTR_KIND_NO_UNWIND;
699   case Attribute::NoSanitizeBounds:
700     return bitc::ATTR_KIND_NO_SANITIZE_BOUNDS;
701   case Attribute::NoSanitizeCoverage:
702     return bitc::ATTR_KIND_NO_SANITIZE_COVERAGE;
703   case Attribute::NullPointerIsValid:
704     return bitc::ATTR_KIND_NULL_POINTER_IS_VALID;
705   case Attribute::OptForFuzzing:
706     return bitc::ATTR_KIND_OPT_FOR_FUZZING;
707   case Attribute::OptimizeForSize:
708     return bitc::ATTR_KIND_OPTIMIZE_FOR_SIZE;
709   case Attribute::OptimizeNone:
710     return bitc::ATTR_KIND_OPTIMIZE_NONE;
711   case Attribute::ReadNone:
712     return bitc::ATTR_KIND_READ_NONE;
713   case Attribute::ReadOnly:
714     return bitc::ATTR_KIND_READ_ONLY;
715   case Attribute::Returned:
716     return bitc::ATTR_KIND_RETURNED;
717   case Attribute::ReturnsTwice:
718     return bitc::ATTR_KIND_RETURNS_TWICE;
719   case Attribute::SExt:
720     return bitc::ATTR_KIND_S_EXT;
721   case Attribute::Speculatable:
722     return bitc::ATTR_KIND_SPECULATABLE;
723   case Attribute::StackAlignment:
724     return bitc::ATTR_KIND_STACK_ALIGNMENT;
725   case Attribute::StackProtect:
726     return bitc::ATTR_KIND_STACK_PROTECT;
727   case Attribute::StackProtectReq:
728     return bitc::ATTR_KIND_STACK_PROTECT_REQ;
729   case Attribute::StackProtectStrong:
730     return bitc::ATTR_KIND_STACK_PROTECT_STRONG;
731   case Attribute::SafeStack:
732     return bitc::ATTR_KIND_SAFESTACK;
733   case Attribute::ShadowCallStack:
734     return bitc::ATTR_KIND_SHADOWCALLSTACK;
735   case Attribute::StrictFP:
736     return bitc::ATTR_KIND_STRICT_FP;
737   case Attribute::StructRet:
738     return bitc::ATTR_KIND_STRUCT_RET;
739   case Attribute::SanitizeAddress:
740     return bitc::ATTR_KIND_SANITIZE_ADDRESS;
741   case Attribute::SanitizeHWAddress:
742     return bitc::ATTR_KIND_SANITIZE_HWADDRESS;
743   case Attribute::SanitizeThread:
744     return bitc::ATTR_KIND_SANITIZE_THREAD;
745   case Attribute::SanitizeMemory:
746     return bitc::ATTR_KIND_SANITIZE_MEMORY;
747   case Attribute::SpeculativeLoadHardening:
748     return bitc::ATTR_KIND_SPECULATIVE_LOAD_HARDENING;
749   case Attribute::SwiftError:
750     return bitc::ATTR_KIND_SWIFT_ERROR;
751   case Attribute::SwiftSelf:
752     return bitc::ATTR_KIND_SWIFT_SELF;
753   case Attribute::SwiftAsync:
754     return bitc::ATTR_KIND_SWIFT_ASYNC;
755   case Attribute::UWTable:
756     return bitc::ATTR_KIND_UW_TABLE;
757   case Attribute::VScaleRange:
758     return bitc::ATTR_KIND_VSCALE_RANGE;
759   case Attribute::WillReturn:
760     return bitc::ATTR_KIND_WILLRETURN;
761   case Attribute::WriteOnly:
762     return bitc::ATTR_KIND_WRITEONLY;
763   case Attribute::ZExt:
764     return bitc::ATTR_KIND_Z_EXT;
765   case Attribute::ImmArg:
766     return bitc::ATTR_KIND_IMMARG;
767   case Attribute::SanitizeMemTag:
768     return bitc::ATTR_KIND_SANITIZE_MEMTAG;
769   case Attribute::Preallocated:
770     return bitc::ATTR_KIND_PREALLOCATED;
771   case Attribute::NoUndef:
772     return bitc::ATTR_KIND_NOUNDEF;
773   case Attribute::ByRef:
774     return bitc::ATTR_KIND_BYREF;
775   case Attribute::MustProgress:
776     return bitc::ATTR_KIND_MUSTPROGRESS;
777   case Attribute::EndAttrKinds:
778     llvm_unreachable("Can not encode end-attribute kinds marker.");
779   case Attribute::None:
780     llvm_unreachable("Can not encode none-attribute.");
781   case Attribute::EmptyKey:
782   case Attribute::TombstoneKey:
783     llvm_unreachable("Trying to encode EmptyKey/TombstoneKey");
784   }
785 
786   llvm_unreachable("Trying to encode unknown attribute");
787 }
788 
789 void ModuleBitcodeWriter::writeAttributeGroupTable() {
790   const std::vector<ValueEnumerator::IndexAndAttrSet> &AttrGrps =
791       VE.getAttributeGroups();
792   if (AttrGrps.empty()) return;
793 
794   Stream.EnterSubblock(bitc::PARAMATTR_GROUP_BLOCK_ID, 3);
795 
796   SmallVector<uint64_t, 64> Record;
797   for (ValueEnumerator::IndexAndAttrSet Pair : AttrGrps) {
798     unsigned AttrListIndex = Pair.first;
799     AttributeSet AS = Pair.second;
800     Record.push_back(VE.getAttributeGroupID(Pair));
801     Record.push_back(AttrListIndex);
802 
803     for (Attribute Attr : AS) {
804       if (Attr.isEnumAttribute()) {
805         Record.push_back(0);
806         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
807       } else if (Attr.isIntAttribute()) {
808         Record.push_back(1);
809         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
810         Record.push_back(Attr.getValueAsInt());
811       } else if (Attr.isStringAttribute()) {
812         StringRef Kind = Attr.getKindAsString();
813         StringRef Val = Attr.getValueAsString();
814 
815         Record.push_back(Val.empty() ? 3 : 4);
816         Record.append(Kind.begin(), Kind.end());
817         Record.push_back(0);
818         if (!Val.empty()) {
819           Record.append(Val.begin(), Val.end());
820           Record.push_back(0);
821         }
822       } else {
823         assert(Attr.isTypeAttribute());
824         Type *Ty = Attr.getValueAsType();
825         Record.push_back(Ty ? 6 : 5);
826         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
827         if (Ty)
828           Record.push_back(VE.getTypeID(Attr.getValueAsType()));
829       }
830     }
831 
832     Stream.EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
833     Record.clear();
834   }
835 
836   Stream.ExitBlock();
837 }
838 
839 void ModuleBitcodeWriter::writeAttributeTable() {
840   const std::vector<AttributeList> &Attrs = VE.getAttributeLists();
841   if (Attrs.empty()) return;
842 
843   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
844 
845   SmallVector<uint64_t, 64> Record;
846   for (const AttributeList &AL : Attrs) {
847     for (unsigned i : AL.indexes()) {
848       AttributeSet AS = AL.getAttributes(i);
849       if (AS.hasAttributes())
850         Record.push_back(VE.getAttributeGroupID({i, AS}));
851     }
852 
853     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
854     Record.clear();
855   }
856 
857   Stream.ExitBlock();
858 }
859 
860 /// WriteTypeTable - Write out the type table for a module.
861 void ModuleBitcodeWriter::writeTypeTable() {
862   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
863 
864   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
865   SmallVector<uint64_t, 64> TypeVals;
866 
867   uint64_t NumBits = VE.computeBitsRequiredForTypeIndicies();
868 
869   // Abbrev for TYPE_CODE_POINTER.
870   auto Abbv = std::make_shared<BitCodeAbbrev>();
871   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
872   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
873   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
874   unsigned PtrAbbrev = Stream.EmitAbbrev(std::move(Abbv));
875 
876   // Abbrev for TYPE_CODE_OPAQUE_POINTER.
877   Abbv = std::make_shared<BitCodeAbbrev>();
878   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_OPAQUE_POINTER));
879   Abbv->Add(BitCodeAbbrevOp(0)); // Addrspace = 0
880   unsigned OpaquePtrAbbrev = Stream.EmitAbbrev(std::move(Abbv));
881 
882   // Abbrev for TYPE_CODE_FUNCTION.
883   Abbv = std::make_shared<BitCodeAbbrev>();
884   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
885   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
886   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
887   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
888   unsigned FunctionAbbrev = Stream.EmitAbbrev(std::move(Abbv));
889 
890   // Abbrev for TYPE_CODE_STRUCT_ANON.
891   Abbv = std::make_shared<BitCodeAbbrev>();
892   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
893   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
894   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
895   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
896   unsigned StructAnonAbbrev = Stream.EmitAbbrev(std::move(Abbv));
897 
898   // Abbrev for TYPE_CODE_STRUCT_NAME.
899   Abbv = std::make_shared<BitCodeAbbrev>();
900   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
901   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
902   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
903   unsigned StructNameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
904 
905   // Abbrev for TYPE_CODE_STRUCT_NAMED.
906   Abbv = std::make_shared<BitCodeAbbrev>();
907   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
908   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
909   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
910   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
911   unsigned StructNamedAbbrev = Stream.EmitAbbrev(std::move(Abbv));
912 
913   // Abbrev for TYPE_CODE_ARRAY.
914   Abbv = std::make_shared<BitCodeAbbrev>();
915   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
916   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
917   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
918   unsigned ArrayAbbrev = Stream.EmitAbbrev(std::move(Abbv));
919 
920   // Emit an entry count so the reader can reserve space.
921   TypeVals.push_back(TypeList.size());
922   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
923   TypeVals.clear();
924 
925   // Loop over all of the types, emitting each in turn.
926   for (Type *T : TypeList) {
927     int AbbrevToUse = 0;
928     unsigned Code = 0;
929 
930     switch (T->getTypeID()) {
931     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;      break;
932     case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;      break;
933     case Type::BFloatTyID:    Code = bitc::TYPE_CODE_BFLOAT;    break;
934     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;     break;
935     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE;    break;
936     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80;  break;
937     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128;     break;
938     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
939     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;     break;
940     case Type::MetadataTyID:  Code = bitc::TYPE_CODE_METADATA;  break;
941     case Type::X86_MMXTyID:   Code = bitc::TYPE_CODE_X86_MMX;   break;
942     case Type::X86_AMXTyID:   Code = bitc::TYPE_CODE_X86_AMX;   break;
943     case Type::TokenTyID:     Code = bitc::TYPE_CODE_TOKEN;     break;
944     case Type::IntegerTyID:
945       // INTEGER: [width]
946       Code = bitc::TYPE_CODE_INTEGER;
947       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
948       break;
949     case Type::PointerTyID: {
950       PointerType *PTy = cast<PointerType>(T);
951       unsigned AddressSpace = PTy->getAddressSpace();
952       if (PTy->isOpaque()) {
953         // OPAQUE_POINTER: [address space]
954         Code = bitc::TYPE_CODE_OPAQUE_POINTER;
955         TypeVals.push_back(AddressSpace);
956         if (AddressSpace == 0)
957           AbbrevToUse = OpaquePtrAbbrev;
958       } else {
959         // POINTER: [pointee type, address space]
960         Code = bitc::TYPE_CODE_POINTER;
961         TypeVals.push_back(VE.getTypeID(PTy->getNonOpaquePointerElementType()));
962         TypeVals.push_back(AddressSpace);
963         if (AddressSpace == 0)
964           AbbrevToUse = PtrAbbrev;
965       }
966       break;
967     }
968     case Type::FunctionTyID: {
969       FunctionType *FT = cast<FunctionType>(T);
970       // FUNCTION: [isvararg, retty, paramty x N]
971       Code = bitc::TYPE_CODE_FUNCTION;
972       TypeVals.push_back(FT->isVarArg());
973       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
974       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
975         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
976       AbbrevToUse = FunctionAbbrev;
977       break;
978     }
979     case Type::StructTyID: {
980       StructType *ST = cast<StructType>(T);
981       // STRUCT: [ispacked, eltty x N]
982       TypeVals.push_back(ST->isPacked());
983       // Output all of the element types.
984       for (Type *ET : ST->elements())
985         TypeVals.push_back(VE.getTypeID(ET));
986 
987       if (ST->isLiteral()) {
988         Code = bitc::TYPE_CODE_STRUCT_ANON;
989         AbbrevToUse = StructAnonAbbrev;
990       } else {
991         if (ST->isOpaque()) {
992           Code = bitc::TYPE_CODE_OPAQUE;
993         } else {
994           Code = bitc::TYPE_CODE_STRUCT_NAMED;
995           AbbrevToUse = StructNamedAbbrev;
996         }
997 
998         // Emit the name if it is present.
999         if (!ST->getName().empty())
1000           writeStringRecord(Stream, bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
1001                             StructNameAbbrev);
1002       }
1003       break;
1004     }
1005     case Type::ArrayTyID: {
1006       ArrayType *AT = cast<ArrayType>(T);
1007       // ARRAY: [numelts, eltty]
1008       Code = bitc::TYPE_CODE_ARRAY;
1009       TypeVals.push_back(AT->getNumElements());
1010       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
1011       AbbrevToUse = ArrayAbbrev;
1012       break;
1013     }
1014     case Type::FixedVectorTyID:
1015     case Type::ScalableVectorTyID: {
1016       VectorType *VT = cast<VectorType>(T);
1017       // VECTOR [numelts, eltty] or
1018       //        [numelts, eltty, scalable]
1019       Code = bitc::TYPE_CODE_VECTOR;
1020       TypeVals.push_back(VT->getElementCount().getKnownMinValue());
1021       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
1022       if (isa<ScalableVectorType>(VT))
1023         TypeVals.push_back(true);
1024       break;
1025     }
1026     case Type::DXILPointerTyID:
1027       llvm_unreachable("DXIL pointers cannot be added to IR modules");
1028     }
1029 
1030     // Emit the finished record.
1031     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
1032     TypeVals.clear();
1033   }
1034 
1035   Stream.ExitBlock();
1036 }
1037 
1038 static unsigned getEncodedLinkage(const GlobalValue::LinkageTypes Linkage) {
1039   switch (Linkage) {
1040   case GlobalValue::ExternalLinkage:
1041     return 0;
1042   case GlobalValue::WeakAnyLinkage:
1043     return 16;
1044   case GlobalValue::AppendingLinkage:
1045     return 2;
1046   case GlobalValue::InternalLinkage:
1047     return 3;
1048   case GlobalValue::LinkOnceAnyLinkage:
1049     return 18;
1050   case GlobalValue::ExternalWeakLinkage:
1051     return 7;
1052   case GlobalValue::CommonLinkage:
1053     return 8;
1054   case GlobalValue::PrivateLinkage:
1055     return 9;
1056   case GlobalValue::WeakODRLinkage:
1057     return 17;
1058   case GlobalValue::LinkOnceODRLinkage:
1059     return 19;
1060   case GlobalValue::AvailableExternallyLinkage:
1061     return 12;
1062   }
1063   llvm_unreachable("Invalid linkage");
1064 }
1065 
1066 static unsigned getEncodedLinkage(const GlobalValue &GV) {
1067   return getEncodedLinkage(GV.getLinkage());
1068 }
1069 
1070 static uint64_t getEncodedFFlags(FunctionSummary::FFlags Flags) {
1071   uint64_t RawFlags = 0;
1072   RawFlags |= Flags.ReadNone;
1073   RawFlags |= (Flags.ReadOnly << 1);
1074   RawFlags |= (Flags.NoRecurse << 2);
1075   RawFlags |= (Flags.ReturnDoesNotAlias << 3);
1076   RawFlags |= (Flags.NoInline << 4);
1077   RawFlags |= (Flags.AlwaysInline << 5);
1078   RawFlags |= (Flags.NoUnwind << 6);
1079   RawFlags |= (Flags.MayThrow << 7);
1080   RawFlags |= (Flags.HasUnknownCall << 8);
1081   RawFlags |= (Flags.MustBeUnreachable << 9);
1082   return RawFlags;
1083 }
1084 
1085 // Decode the flags for GlobalValue in the summary. See getDecodedGVSummaryFlags
1086 // in BitcodeReader.cpp.
1087 static uint64_t getEncodedGVSummaryFlags(GlobalValueSummary::GVFlags Flags) {
1088   uint64_t RawFlags = 0;
1089 
1090   RawFlags |= Flags.NotEligibleToImport; // bool
1091   RawFlags |= (Flags.Live << 1);
1092   RawFlags |= (Flags.DSOLocal << 2);
1093   RawFlags |= (Flags.CanAutoHide << 3);
1094 
1095   // Linkage don't need to be remapped at that time for the summary. Any future
1096   // change to the getEncodedLinkage() function will need to be taken into
1097   // account here as well.
1098   RawFlags = (RawFlags << 4) | Flags.Linkage; // 4 bits
1099 
1100   RawFlags |= (Flags.Visibility << 8); // 2 bits
1101 
1102   return RawFlags;
1103 }
1104 
1105 static uint64_t getEncodedGVarFlags(GlobalVarSummary::GVarFlags Flags) {
1106   uint64_t RawFlags = Flags.MaybeReadOnly | (Flags.MaybeWriteOnly << 1) |
1107                       (Flags.Constant << 2) | Flags.VCallVisibility << 3;
1108   return RawFlags;
1109 }
1110 
1111 static unsigned getEncodedVisibility(const GlobalValue &GV) {
1112   switch (GV.getVisibility()) {
1113   case GlobalValue::DefaultVisibility:   return 0;
1114   case GlobalValue::HiddenVisibility:    return 1;
1115   case GlobalValue::ProtectedVisibility: return 2;
1116   }
1117   llvm_unreachable("Invalid visibility");
1118 }
1119 
1120 static unsigned getEncodedDLLStorageClass(const GlobalValue &GV) {
1121   switch (GV.getDLLStorageClass()) {
1122   case GlobalValue::DefaultStorageClass:   return 0;
1123   case GlobalValue::DLLImportStorageClass: return 1;
1124   case GlobalValue::DLLExportStorageClass: return 2;
1125   }
1126   llvm_unreachable("Invalid DLL storage class");
1127 }
1128 
1129 static unsigned getEncodedThreadLocalMode(const GlobalValue &GV) {
1130   switch (GV.getThreadLocalMode()) {
1131     case GlobalVariable::NotThreadLocal:         return 0;
1132     case GlobalVariable::GeneralDynamicTLSModel: return 1;
1133     case GlobalVariable::LocalDynamicTLSModel:   return 2;
1134     case GlobalVariable::InitialExecTLSModel:    return 3;
1135     case GlobalVariable::LocalExecTLSModel:      return 4;
1136   }
1137   llvm_unreachable("Invalid TLS model");
1138 }
1139 
1140 static unsigned getEncodedComdatSelectionKind(const Comdat &C) {
1141   switch (C.getSelectionKind()) {
1142   case Comdat::Any:
1143     return bitc::COMDAT_SELECTION_KIND_ANY;
1144   case Comdat::ExactMatch:
1145     return bitc::COMDAT_SELECTION_KIND_EXACT_MATCH;
1146   case Comdat::Largest:
1147     return bitc::COMDAT_SELECTION_KIND_LARGEST;
1148   case Comdat::NoDeduplicate:
1149     return bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES;
1150   case Comdat::SameSize:
1151     return bitc::COMDAT_SELECTION_KIND_SAME_SIZE;
1152   }
1153   llvm_unreachable("Invalid selection kind");
1154 }
1155 
1156 static unsigned getEncodedUnnamedAddr(const GlobalValue &GV) {
1157   switch (GV.getUnnamedAddr()) {
1158   case GlobalValue::UnnamedAddr::None:   return 0;
1159   case GlobalValue::UnnamedAddr::Local:  return 2;
1160   case GlobalValue::UnnamedAddr::Global: return 1;
1161   }
1162   llvm_unreachable("Invalid unnamed_addr");
1163 }
1164 
1165 size_t ModuleBitcodeWriter::addToStrtab(StringRef Str) {
1166   if (GenerateHash)
1167     Hasher.update(Str);
1168   return StrtabBuilder.add(Str);
1169 }
1170 
1171 void ModuleBitcodeWriter::writeComdats() {
1172   SmallVector<unsigned, 64> Vals;
1173   for (const Comdat *C : VE.getComdats()) {
1174     // COMDAT: [strtab offset, strtab size, selection_kind]
1175     Vals.push_back(addToStrtab(C->getName()));
1176     Vals.push_back(C->getName().size());
1177     Vals.push_back(getEncodedComdatSelectionKind(*C));
1178     Stream.EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
1179     Vals.clear();
1180   }
1181 }
1182 
1183 /// Write a record that will eventually hold the word offset of the
1184 /// module-level VST. For now the offset is 0, which will be backpatched
1185 /// after the real VST is written. Saves the bit offset to backpatch.
1186 void ModuleBitcodeWriter::writeValueSymbolTableForwardDecl() {
1187   // Write a placeholder value in for the offset of the real VST,
1188   // which is written after the function blocks so that it can include
1189   // the offset of each function. The placeholder offset will be
1190   // updated when the real VST is written.
1191   auto Abbv = std::make_shared<BitCodeAbbrev>();
1192   Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_VSTOFFSET));
1193   // Blocks are 32-bit aligned, so we can use a 32-bit word offset to
1194   // hold the real VST offset. Must use fixed instead of VBR as we don't
1195   // know how many VBR chunks to reserve ahead of time.
1196   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
1197   unsigned VSTOffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1198 
1199   // Emit the placeholder
1200   uint64_t Vals[] = {bitc::MODULE_CODE_VSTOFFSET, 0};
1201   Stream.EmitRecordWithAbbrev(VSTOffsetAbbrev, Vals);
1202 
1203   // Compute and save the bit offset to the placeholder, which will be
1204   // patched when the real VST is written. We can simply subtract the 32-bit
1205   // fixed size from the current bit number to get the location to backpatch.
1206   VSTOffsetPlaceholder = Stream.GetCurrentBitNo() - 32;
1207 }
1208 
1209 enum StringEncoding { SE_Char6, SE_Fixed7, SE_Fixed8 };
1210 
1211 /// Determine the encoding to use for the given string name and length.
1212 static StringEncoding getStringEncoding(StringRef Str) {
1213   bool isChar6 = true;
1214   for (char C : Str) {
1215     if (isChar6)
1216       isChar6 = BitCodeAbbrevOp::isChar6(C);
1217     if ((unsigned char)C & 128)
1218       // don't bother scanning the rest.
1219       return SE_Fixed8;
1220   }
1221   if (isChar6)
1222     return SE_Char6;
1223   return SE_Fixed7;
1224 }
1225 
1226 static_assert(sizeof(GlobalValue::SanitizerMetadata) <= sizeof(unsigned),
1227               "Sanitizer Metadata is too large for naive serialization.");
1228 static unsigned
1229 serializeSanitizerMetadata(const GlobalValue::SanitizerMetadata &Meta) {
1230   return Meta.NoAddress | (Meta.NoHWAddress << 1) |
1231          (Meta.NoMemtag << 2) | (Meta.IsDynInit << 3);
1232 }
1233 
1234 /// Emit top-level description of module, including target triple, inline asm,
1235 /// descriptors for global variables, and function prototype info.
1236 /// Returns the bit offset to backpatch with the location of the real VST.
1237 void ModuleBitcodeWriter::writeModuleInfo() {
1238   // Emit various pieces of data attached to a module.
1239   if (!M.getTargetTriple().empty())
1240     writeStringRecord(Stream, bitc::MODULE_CODE_TRIPLE, M.getTargetTriple(),
1241                       0 /*TODO*/);
1242   const std::string &DL = M.getDataLayoutStr();
1243   if (!DL.empty())
1244     writeStringRecord(Stream, bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/);
1245   if (!M.getModuleInlineAsm().empty())
1246     writeStringRecord(Stream, bitc::MODULE_CODE_ASM, M.getModuleInlineAsm(),
1247                       0 /*TODO*/);
1248 
1249   // Emit information about sections and GC, computing how many there are. Also
1250   // compute the maximum alignment value.
1251   std::map<std::string, unsigned> SectionMap;
1252   std::map<std::string, unsigned> GCMap;
1253   MaybeAlign MaxAlignment;
1254   unsigned MaxGlobalType = 0;
1255   const auto UpdateMaxAlignment = [&MaxAlignment](const MaybeAlign A) {
1256     if (A)
1257       MaxAlignment = !MaxAlignment ? *A : std::max(*MaxAlignment, *A);
1258   };
1259   for (const GlobalVariable &GV : M.globals()) {
1260     UpdateMaxAlignment(GV.getAlign());
1261     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getValueType()));
1262     if (GV.hasSection()) {
1263       // Give section names unique ID's.
1264       unsigned &Entry = SectionMap[std::string(GV.getSection())];
1265       if (!Entry) {
1266         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
1267                           0 /*TODO*/);
1268         Entry = SectionMap.size();
1269       }
1270     }
1271   }
1272   for (const Function &F : M) {
1273     UpdateMaxAlignment(F.getAlign());
1274     if (F.hasSection()) {
1275       // Give section names unique ID's.
1276       unsigned &Entry = SectionMap[std::string(F.getSection())];
1277       if (!Entry) {
1278         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
1279                           0 /*TODO*/);
1280         Entry = SectionMap.size();
1281       }
1282     }
1283     if (F.hasGC()) {
1284       // Same for GC names.
1285       unsigned &Entry = GCMap[F.getGC()];
1286       if (!Entry) {
1287         writeStringRecord(Stream, bitc::MODULE_CODE_GCNAME, F.getGC(),
1288                           0 /*TODO*/);
1289         Entry = GCMap.size();
1290       }
1291     }
1292   }
1293 
1294   // Emit abbrev for globals, now that we know # sections and max alignment.
1295   unsigned SimpleGVarAbbrev = 0;
1296   if (!M.global_empty()) {
1297     // Add an abbrev for common globals with no visibility or thread localness.
1298     auto Abbv = std::make_shared<BitCodeAbbrev>();
1299     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
1300     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1301     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1302     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1303                               Log2_32_Ceil(MaxGlobalType+1)));
1304     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddrSpace << 2
1305                                                            //| explicitType << 1
1306                                                            //| constant
1307     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Initializer.
1308     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // Linkage.
1309     if (!MaxAlignment)                                     // Alignment.
1310       Abbv->Add(BitCodeAbbrevOp(0));
1311     else {
1312       unsigned MaxEncAlignment = getEncodedAlign(MaxAlignment);
1313       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1314                                Log2_32_Ceil(MaxEncAlignment+1)));
1315     }
1316     if (SectionMap.empty())                                    // Section.
1317       Abbv->Add(BitCodeAbbrevOp(0));
1318     else
1319       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1320                                Log2_32_Ceil(SectionMap.size()+1)));
1321     // Don't bother emitting vis + thread local.
1322     SimpleGVarAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1323   }
1324 
1325   SmallVector<unsigned, 64> Vals;
1326   // Emit the module's source file name.
1327   {
1328     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
1329     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
1330     if (Bits == SE_Char6)
1331       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
1332     else if (Bits == SE_Fixed7)
1333       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
1334 
1335     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
1336     auto Abbv = std::make_shared<BitCodeAbbrev>();
1337     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
1338     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1339     Abbv->Add(AbbrevOpToUse);
1340     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1341 
1342     for (const auto P : M.getSourceFileName())
1343       Vals.push_back((unsigned char)P);
1344 
1345     // Emit the finished record.
1346     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
1347     Vals.clear();
1348   }
1349 
1350   // Emit the global variable information.
1351   for (const GlobalVariable &GV : M.globals()) {
1352     unsigned AbbrevToUse = 0;
1353 
1354     // GLOBALVAR: [strtab offset, strtab size, type, isconst, initid,
1355     //             linkage, alignment, section, visibility, threadlocal,
1356     //             unnamed_addr, externally_initialized, dllstorageclass,
1357     //             comdat, attributes, DSO_Local, GlobalSanitizer]
1358     Vals.push_back(addToStrtab(GV.getName()));
1359     Vals.push_back(GV.getName().size());
1360     Vals.push_back(VE.getTypeID(GV.getValueType()));
1361     Vals.push_back(GV.getType()->getAddressSpace() << 2 | 2 | GV.isConstant());
1362     Vals.push_back(GV.isDeclaration() ? 0 :
1363                    (VE.getValueID(GV.getInitializer()) + 1));
1364     Vals.push_back(getEncodedLinkage(GV));
1365     Vals.push_back(getEncodedAlign(GV.getAlign()));
1366     Vals.push_back(GV.hasSection() ? SectionMap[std::string(GV.getSection())]
1367                                    : 0);
1368     if (GV.isThreadLocal() ||
1369         GV.getVisibility() != GlobalValue::DefaultVisibility ||
1370         GV.getUnnamedAddr() != GlobalValue::UnnamedAddr::None ||
1371         GV.isExternallyInitialized() ||
1372         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
1373         GV.hasComdat() || GV.hasAttributes() || GV.isDSOLocal() ||
1374         GV.hasPartition() || GV.hasSanitizerMetadata()) {
1375       Vals.push_back(getEncodedVisibility(GV));
1376       Vals.push_back(getEncodedThreadLocalMode(GV));
1377       Vals.push_back(getEncodedUnnamedAddr(GV));
1378       Vals.push_back(GV.isExternallyInitialized());
1379       Vals.push_back(getEncodedDLLStorageClass(GV));
1380       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
1381 
1382       auto AL = GV.getAttributesAsList(AttributeList::FunctionIndex);
1383       Vals.push_back(VE.getAttributeListID(AL));
1384 
1385       Vals.push_back(GV.isDSOLocal());
1386       Vals.push_back(addToStrtab(GV.getPartition()));
1387       Vals.push_back(GV.getPartition().size());
1388 
1389       if (GV.hasSanitizerMetadata())
1390         Vals.push_back(serializeSanitizerMetadata(GV.getSanitizerMetadata()));
1391       else
1392         Vals.push_back(UINT_MAX);
1393     } else {
1394       AbbrevToUse = SimpleGVarAbbrev;
1395     }
1396 
1397     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
1398     Vals.clear();
1399   }
1400 
1401   // Emit the function proto information.
1402   for (const Function &F : M) {
1403     // FUNCTION:  [strtab offset, strtab size, type, callingconv, isproto,
1404     //             linkage, paramattrs, alignment, section, visibility, gc,
1405     //             unnamed_addr, prologuedata, dllstorageclass, comdat,
1406     //             prefixdata, personalityfn, DSO_Local, addrspace]
1407     Vals.push_back(addToStrtab(F.getName()));
1408     Vals.push_back(F.getName().size());
1409     Vals.push_back(VE.getTypeID(F.getFunctionType()));
1410     Vals.push_back(F.getCallingConv());
1411     Vals.push_back(F.isDeclaration());
1412     Vals.push_back(getEncodedLinkage(F));
1413     Vals.push_back(VE.getAttributeListID(F.getAttributes()));
1414     Vals.push_back(getEncodedAlign(F.getAlign()));
1415     Vals.push_back(F.hasSection() ? SectionMap[std::string(F.getSection())]
1416                                   : 0);
1417     Vals.push_back(getEncodedVisibility(F));
1418     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
1419     Vals.push_back(getEncodedUnnamedAddr(F));
1420     Vals.push_back(F.hasPrologueData() ? (VE.getValueID(F.getPrologueData()) + 1)
1421                                        : 0);
1422     Vals.push_back(getEncodedDLLStorageClass(F));
1423     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
1424     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
1425                                      : 0);
1426     Vals.push_back(
1427         F.hasPersonalityFn() ? (VE.getValueID(F.getPersonalityFn()) + 1) : 0);
1428 
1429     Vals.push_back(F.isDSOLocal());
1430     Vals.push_back(F.getAddressSpace());
1431     Vals.push_back(addToStrtab(F.getPartition()));
1432     Vals.push_back(F.getPartition().size());
1433 
1434     unsigned AbbrevToUse = 0;
1435     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
1436     Vals.clear();
1437   }
1438 
1439   // Emit the alias information.
1440   for (const GlobalAlias &A : M.aliases()) {
1441     // ALIAS: [strtab offset, strtab size, alias type, aliasee val#, linkage,
1442     //         visibility, dllstorageclass, threadlocal, unnamed_addr,
1443     //         DSO_Local]
1444     Vals.push_back(addToStrtab(A.getName()));
1445     Vals.push_back(A.getName().size());
1446     Vals.push_back(VE.getTypeID(A.getValueType()));
1447     Vals.push_back(A.getType()->getAddressSpace());
1448     Vals.push_back(VE.getValueID(A.getAliasee()));
1449     Vals.push_back(getEncodedLinkage(A));
1450     Vals.push_back(getEncodedVisibility(A));
1451     Vals.push_back(getEncodedDLLStorageClass(A));
1452     Vals.push_back(getEncodedThreadLocalMode(A));
1453     Vals.push_back(getEncodedUnnamedAddr(A));
1454     Vals.push_back(A.isDSOLocal());
1455     Vals.push_back(addToStrtab(A.getPartition()));
1456     Vals.push_back(A.getPartition().size());
1457 
1458     unsigned AbbrevToUse = 0;
1459     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
1460     Vals.clear();
1461   }
1462 
1463   // Emit the ifunc information.
1464   for (const GlobalIFunc &I : M.ifuncs()) {
1465     // IFUNC: [strtab offset, strtab size, ifunc type, address space, resolver
1466     //         val#, linkage, visibility, DSO_Local]
1467     Vals.push_back(addToStrtab(I.getName()));
1468     Vals.push_back(I.getName().size());
1469     Vals.push_back(VE.getTypeID(I.getValueType()));
1470     Vals.push_back(I.getType()->getAddressSpace());
1471     Vals.push_back(VE.getValueID(I.getResolver()));
1472     Vals.push_back(getEncodedLinkage(I));
1473     Vals.push_back(getEncodedVisibility(I));
1474     Vals.push_back(I.isDSOLocal());
1475     Vals.push_back(addToStrtab(I.getPartition()));
1476     Vals.push_back(I.getPartition().size());
1477     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
1478     Vals.clear();
1479   }
1480 
1481   writeValueSymbolTableForwardDecl();
1482 }
1483 
1484 static uint64_t getOptimizationFlags(const Value *V) {
1485   uint64_t Flags = 0;
1486 
1487   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
1488     if (OBO->hasNoSignedWrap())
1489       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
1490     if (OBO->hasNoUnsignedWrap())
1491       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
1492   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
1493     if (PEO->isExact())
1494       Flags |= 1 << bitc::PEO_EXACT;
1495   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
1496     if (FPMO->hasAllowReassoc())
1497       Flags |= bitc::AllowReassoc;
1498     if (FPMO->hasNoNaNs())
1499       Flags |= bitc::NoNaNs;
1500     if (FPMO->hasNoInfs())
1501       Flags |= bitc::NoInfs;
1502     if (FPMO->hasNoSignedZeros())
1503       Flags |= bitc::NoSignedZeros;
1504     if (FPMO->hasAllowReciprocal())
1505       Flags |= bitc::AllowReciprocal;
1506     if (FPMO->hasAllowContract())
1507       Flags |= bitc::AllowContract;
1508     if (FPMO->hasApproxFunc())
1509       Flags |= bitc::ApproxFunc;
1510   }
1511 
1512   return Flags;
1513 }
1514 
1515 void ModuleBitcodeWriter::writeValueAsMetadata(
1516     const ValueAsMetadata *MD, SmallVectorImpl<uint64_t> &Record) {
1517   // Mimic an MDNode with a value as one operand.
1518   Value *V = MD->getValue();
1519   Record.push_back(VE.getTypeID(V->getType()));
1520   Record.push_back(VE.getValueID(V));
1521   Stream.EmitRecord(bitc::METADATA_VALUE, Record, 0);
1522   Record.clear();
1523 }
1524 
1525 void ModuleBitcodeWriter::writeMDTuple(const MDTuple *N,
1526                                        SmallVectorImpl<uint64_t> &Record,
1527                                        unsigned Abbrev) {
1528   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
1529     Metadata *MD = N->getOperand(i);
1530     assert(!(MD && isa<LocalAsMetadata>(MD)) &&
1531            "Unexpected function-local metadata");
1532     Record.push_back(VE.getMetadataOrNullID(MD));
1533   }
1534   Stream.EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
1535                                     : bitc::METADATA_NODE,
1536                     Record, Abbrev);
1537   Record.clear();
1538 }
1539 
1540 unsigned ModuleBitcodeWriter::createDILocationAbbrev() {
1541   // Assume the column is usually under 128, and always output the inlined-at
1542   // location (it's never more expensive than building an array size 1).
1543   auto Abbv = std::make_shared<BitCodeAbbrev>();
1544   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
1545   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1546   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1547   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1548   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1549   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1550   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1551   return Stream.EmitAbbrev(std::move(Abbv));
1552 }
1553 
1554 void ModuleBitcodeWriter::writeDILocation(const DILocation *N,
1555                                           SmallVectorImpl<uint64_t> &Record,
1556                                           unsigned &Abbrev) {
1557   if (!Abbrev)
1558     Abbrev = createDILocationAbbrev();
1559 
1560   Record.push_back(N->isDistinct());
1561   Record.push_back(N->getLine());
1562   Record.push_back(N->getColumn());
1563   Record.push_back(VE.getMetadataID(N->getScope()));
1564   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
1565   Record.push_back(N->isImplicitCode());
1566 
1567   Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
1568   Record.clear();
1569 }
1570 
1571 unsigned ModuleBitcodeWriter::createGenericDINodeAbbrev() {
1572   // Assume the column is usually under 128, and always output the inlined-at
1573   // location (it's never more expensive than building an array size 1).
1574   auto Abbv = std::make_shared<BitCodeAbbrev>();
1575   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
1576   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1577   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1578   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1579   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1580   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1581   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1582   return Stream.EmitAbbrev(std::move(Abbv));
1583 }
1584 
1585 void ModuleBitcodeWriter::writeGenericDINode(const GenericDINode *N,
1586                                              SmallVectorImpl<uint64_t> &Record,
1587                                              unsigned &Abbrev) {
1588   if (!Abbrev)
1589     Abbrev = createGenericDINodeAbbrev();
1590 
1591   Record.push_back(N->isDistinct());
1592   Record.push_back(N->getTag());
1593   Record.push_back(0); // Per-tag version field; unused for now.
1594 
1595   for (auto &I : N->operands())
1596     Record.push_back(VE.getMetadataOrNullID(I));
1597 
1598   Stream.EmitRecord(bitc::METADATA_GENERIC_DEBUG, Record, Abbrev);
1599   Record.clear();
1600 }
1601 
1602 void ModuleBitcodeWriter::writeDISubrange(const DISubrange *N,
1603                                           SmallVectorImpl<uint64_t> &Record,
1604                                           unsigned Abbrev) {
1605   const uint64_t Version = 2 << 1;
1606   Record.push_back((uint64_t)N->isDistinct() | Version);
1607   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1608   Record.push_back(VE.getMetadataOrNullID(N->getRawLowerBound()));
1609   Record.push_back(VE.getMetadataOrNullID(N->getRawUpperBound()));
1610   Record.push_back(VE.getMetadataOrNullID(N->getRawStride()));
1611 
1612   Stream.EmitRecord(bitc::METADATA_SUBRANGE, Record, Abbrev);
1613   Record.clear();
1614 }
1615 
1616 void ModuleBitcodeWriter::writeDIGenericSubrange(
1617     const DIGenericSubrange *N, SmallVectorImpl<uint64_t> &Record,
1618     unsigned Abbrev) {
1619   Record.push_back((uint64_t)N->isDistinct());
1620   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1621   Record.push_back(VE.getMetadataOrNullID(N->getRawLowerBound()));
1622   Record.push_back(VE.getMetadataOrNullID(N->getRawUpperBound()));
1623   Record.push_back(VE.getMetadataOrNullID(N->getRawStride()));
1624 
1625   Stream.EmitRecord(bitc::METADATA_GENERIC_SUBRANGE, Record, Abbrev);
1626   Record.clear();
1627 }
1628 
1629 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
1630   if ((int64_t)V >= 0)
1631     Vals.push_back(V << 1);
1632   else
1633     Vals.push_back((-V << 1) | 1);
1634 }
1635 
1636 static void emitWideAPInt(SmallVectorImpl<uint64_t> &Vals, const APInt &A) {
1637   // We have an arbitrary precision integer value to write whose
1638   // bit width is > 64. However, in canonical unsigned integer
1639   // format it is likely that the high bits are going to be zero.
1640   // So, we only write the number of active words.
1641   unsigned NumWords = A.getActiveWords();
1642   const uint64_t *RawData = A.getRawData();
1643   for (unsigned i = 0; i < NumWords; i++)
1644     emitSignedInt64(Vals, RawData[i]);
1645 }
1646 
1647 void ModuleBitcodeWriter::writeDIEnumerator(const DIEnumerator *N,
1648                                             SmallVectorImpl<uint64_t> &Record,
1649                                             unsigned Abbrev) {
1650   const uint64_t IsBigInt = 1 << 2;
1651   Record.push_back(IsBigInt | (N->isUnsigned() << 1) | N->isDistinct());
1652   Record.push_back(N->getValue().getBitWidth());
1653   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1654   emitWideAPInt(Record, N->getValue());
1655 
1656   Stream.EmitRecord(bitc::METADATA_ENUMERATOR, Record, Abbrev);
1657   Record.clear();
1658 }
1659 
1660 void ModuleBitcodeWriter::writeDIBasicType(const DIBasicType *N,
1661                                            SmallVectorImpl<uint64_t> &Record,
1662                                            unsigned Abbrev) {
1663   Record.push_back(N->isDistinct());
1664   Record.push_back(N->getTag());
1665   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1666   Record.push_back(N->getSizeInBits());
1667   Record.push_back(N->getAlignInBits());
1668   Record.push_back(N->getEncoding());
1669   Record.push_back(N->getFlags());
1670 
1671   Stream.EmitRecord(bitc::METADATA_BASIC_TYPE, Record, Abbrev);
1672   Record.clear();
1673 }
1674 
1675 void ModuleBitcodeWriter::writeDIStringType(const DIStringType *N,
1676                                             SmallVectorImpl<uint64_t> &Record,
1677                                             unsigned Abbrev) {
1678   Record.push_back(N->isDistinct());
1679   Record.push_back(N->getTag());
1680   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1681   Record.push_back(VE.getMetadataOrNullID(N->getStringLength()));
1682   Record.push_back(VE.getMetadataOrNullID(N->getStringLengthExp()));
1683   Record.push_back(VE.getMetadataOrNullID(N->getStringLocationExp()));
1684   Record.push_back(N->getSizeInBits());
1685   Record.push_back(N->getAlignInBits());
1686   Record.push_back(N->getEncoding());
1687 
1688   Stream.EmitRecord(bitc::METADATA_STRING_TYPE, Record, Abbrev);
1689   Record.clear();
1690 }
1691 
1692 void ModuleBitcodeWriter::writeDIDerivedType(const DIDerivedType *N,
1693                                              SmallVectorImpl<uint64_t> &Record,
1694                                              unsigned Abbrev) {
1695   Record.push_back(N->isDistinct());
1696   Record.push_back(N->getTag());
1697   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1698   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1699   Record.push_back(N->getLine());
1700   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1701   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1702   Record.push_back(N->getSizeInBits());
1703   Record.push_back(N->getAlignInBits());
1704   Record.push_back(N->getOffsetInBits());
1705   Record.push_back(N->getFlags());
1706   Record.push_back(VE.getMetadataOrNullID(N->getExtraData()));
1707 
1708   // DWARF address space is encoded as N->getDWARFAddressSpace() + 1. 0 means
1709   // that there is no DWARF address space associated with DIDerivedType.
1710   if (const auto &DWARFAddressSpace = N->getDWARFAddressSpace())
1711     Record.push_back(*DWARFAddressSpace + 1);
1712   else
1713     Record.push_back(0);
1714 
1715   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1716 
1717   Stream.EmitRecord(bitc::METADATA_DERIVED_TYPE, Record, Abbrev);
1718   Record.clear();
1719 }
1720 
1721 void ModuleBitcodeWriter::writeDICompositeType(
1722     const DICompositeType *N, SmallVectorImpl<uint64_t> &Record,
1723     unsigned Abbrev) {
1724   const unsigned IsNotUsedInOldTypeRef = 0x2;
1725   Record.push_back(IsNotUsedInOldTypeRef | (unsigned)N->isDistinct());
1726   Record.push_back(N->getTag());
1727   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1728   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1729   Record.push_back(N->getLine());
1730   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1731   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1732   Record.push_back(N->getSizeInBits());
1733   Record.push_back(N->getAlignInBits());
1734   Record.push_back(N->getOffsetInBits());
1735   Record.push_back(N->getFlags());
1736   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1737   Record.push_back(N->getRuntimeLang());
1738   Record.push_back(VE.getMetadataOrNullID(N->getVTableHolder()));
1739   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1740   Record.push_back(VE.getMetadataOrNullID(N->getRawIdentifier()));
1741   Record.push_back(VE.getMetadataOrNullID(N->getDiscriminator()));
1742   Record.push_back(VE.getMetadataOrNullID(N->getRawDataLocation()));
1743   Record.push_back(VE.getMetadataOrNullID(N->getRawAssociated()));
1744   Record.push_back(VE.getMetadataOrNullID(N->getRawAllocated()));
1745   Record.push_back(VE.getMetadataOrNullID(N->getRawRank()));
1746   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1747 
1748   Stream.EmitRecord(bitc::METADATA_COMPOSITE_TYPE, Record, Abbrev);
1749   Record.clear();
1750 }
1751 
1752 void ModuleBitcodeWriter::writeDISubroutineType(
1753     const DISubroutineType *N, SmallVectorImpl<uint64_t> &Record,
1754     unsigned Abbrev) {
1755   const unsigned HasNoOldTypeRefs = 0x2;
1756   Record.push_back(HasNoOldTypeRefs | (unsigned)N->isDistinct());
1757   Record.push_back(N->getFlags());
1758   Record.push_back(VE.getMetadataOrNullID(N->getTypeArray().get()));
1759   Record.push_back(N->getCC());
1760 
1761   Stream.EmitRecord(bitc::METADATA_SUBROUTINE_TYPE, Record, Abbrev);
1762   Record.clear();
1763 }
1764 
1765 void ModuleBitcodeWriter::writeDIFile(const DIFile *N,
1766                                       SmallVectorImpl<uint64_t> &Record,
1767                                       unsigned Abbrev) {
1768   Record.push_back(N->isDistinct());
1769   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
1770   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
1771   if (N->getRawChecksum()) {
1772     Record.push_back(N->getRawChecksum()->Kind);
1773     Record.push_back(VE.getMetadataOrNullID(N->getRawChecksum()->Value));
1774   } else {
1775     // Maintain backwards compatibility with the old internal representation of
1776     // CSK_None in ChecksumKind by writing nulls here when Checksum is None.
1777     Record.push_back(0);
1778     Record.push_back(VE.getMetadataOrNullID(nullptr));
1779   }
1780   auto Source = N->getRawSource();
1781   if (Source)
1782     Record.push_back(VE.getMetadataOrNullID(*Source));
1783 
1784   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
1785   Record.clear();
1786 }
1787 
1788 void ModuleBitcodeWriter::writeDICompileUnit(const DICompileUnit *N,
1789                                              SmallVectorImpl<uint64_t> &Record,
1790                                              unsigned Abbrev) {
1791   assert(N->isDistinct() && "Expected distinct compile units");
1792   Record.push_back(/* IsDistinct */ true);
1793   Record.push_back(N->getSourceLanguage());
1794   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1795   Record.push_back(VE.getMetadataOrNullID(N->getRawProducer()));
1796   Record.push_back(N->isOptimized());
1797   Record.push_back(VE.getMetadataOrNullID(N->getRawFlags()));
1798   Record.push_back(N->getRuntimeVersion());
1799   Record.push_back(VE.getMetadataOrNullID(N->getRawSplitDebugFilename()));
1800   Record.push_back(N->getEmissionKind());
1801   Record.push_back(VE.getMetadataOrNullID(N->getEnumTypes().get()));
1802   Record.push_back(VE.getMetadataOrNullID(N->getRetainedTypes().get()));
1803   Record.push_back(/* subprograms */ 0);
1804   Record.push_back(VE.getMetadataOrNullID(N->getGlobalVariables().get()));
1805   Record.push_back(VE.getMetadataOrNullID(N->getImportedEntities().get()));
1806   Record.push_back(N->getDWOId());
1807   Record.push_back(VE.getMetadataOrNullID(N->getMacros().get()));
1808   Record.push_back(N->getSplitDebugInlining());
1809   Record.push_back(N->getDebugInfoForProfiling());
1810   Record.push_back((unsigned)N->getNameTableKind());
1811   Record.push_back(N->getRangesBaseAddress());
1812   Record.push_back(VE.getMetadataOrNullID(N->getRawSysRoot()));
1813   Record.push_back(VE.getMetadataOrNullID(N->getRawSDK()));
1814 
1815   Stream.EmitRecord(bitc::METADATA_COMPILE_UNIT, Record, Abbrev);
1816   Record.clear();
1817 }
1818 
1819 void ModuleBitcodeWriter::writeDISubprogram(const DISubprogram *N,
1820                                             SmallVectorImpl<uint64_t> &Record,
1821                                             unsigned Abbrev) {
1822   const uint64_t HasUnitFlag = 1 << 1;
1823   const uint64_t HasSPFlagsFlag = 1 << 2;
1824   Record.push_back(uint64_t(N->isDistinct()) | HasUnitFlag | HasSPFlagsFlag);
1825   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1826   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1827   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1828   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1829   Record.push_back(N->getLine());
1830   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1831   Record.push_back(N->getScopeLine());
1832   Record.push_back(VE.getMetadataOrNullID(N->getContainingType()));
1833   Record.push_back(N->getSPFlags());
1834   Record.push_back(N->getVirtualIndex());
1835   Record.push_back(N->getFlags());
1836   Record.push_back(VE.getMetadataOrNullID(N->getRawUnit()));
1837   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1838   Record.push_back(VE.getMetadataOrNullID(N->getDeclaration()));
1839   Record.push_back(VE.getMetadataOrNullID(N->getRetainedNodes().get()));
1840   Record.push_back(N->getThisAdjustment());
1841   Record.push_back(VE.getMetadataOrNullID(N->getThrownTypes().get()));
1842   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1843   Record.push_back(VE.getMetadataOrNullID(N->getRawTargetFuncName()));
1844 
1845   Stream.EmitRecord(bitc::METADATA_SUBPROGRAM, Record, Abbrev);
1846   Record.clear();
1847 }
1848 
1849 void ModuleBitcodeWriter::writeDILexicalBlock(const DILexicalBlock *N,
1850                                               SmallVectorImpl<uint64_t> &Record,
1851                                               unsigned Abbrev) {
1852   Record.push_back(N->isDistinct());
1853   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1854   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1855   Record.push_back(N->getLine());
1856   Record.push_back(N->getColumn());
1857 
1858   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK, Record, Abbrev);
1859   Record.clear();
1860 }
1861 
1862 void ModuleBitcodeWriter::writeDILexicalBlockFile(
1863     const DILexicalBlockFile *N, SmallVectorImpl<uint64_t> &Record,
1864     unsigned Abbrev) {
1865   Record.push_back(N->isDistinct());
1866   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1867   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1868   Record.push_back(N->getDiscriminator());
1869 
1870   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK_FILE, Record, Abbrev);
1871   Record.clear();
1872 }
1873 
1874 void ModuleBitcodeWriter::writeDICommonBlock(const DICommonBlock *N,
1875                                              SmallVectorImpl<uint64_t> &Record,
1876                                              unsigned Abbrev) {
1877   Record.push_back(N->isDistinct());
1878   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1879   Record.push_back(VE.getMetadataOrNullID(N->getDecl()));
1880   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1881   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1882   Record.push_back(N->getLineNo());
1883 
1884   Stream.EmitRecord(bitc::METADATA_COMMON_BLOCK, Record, Abbrev);
1885   Record.clear();
1886 }
1887 
1888 void ModuleBitcodeWriter::writeDINamespace(const DINamespace *N,
1889                                            SmallVectorImpl<uint64_t> &Record,
1890                                            unsigned Abbrev) {
1891   Record.push_back(N->isDistinct() | N->getExportSymbols() << 1);
1892   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1893   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1894 
1895   Stream.EmitRecord(bitc::METADATA_NAMESPACE, Record, Abbrev);
1896   Record.clear();
1897 }
1898 
1899 void ModuleBitcodeWriter::writeDIMacro(const DIMacro *N,
1900                                        SmallVectorImpl<uint64_t> &Record,
1901                                        unsigned Abbrev) {
1902   Record.push_back(N->isDistinct());
1903   Record.push_back(N->getMacinfoType());
1904   Record.push_back(N->getLine());
1905   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1906   Record.push_back(VE.getMetadataOrNullID(N->getRawValue()));
1907 
1908   Stream.EmitRecord(bitc::METADATA_MACRO, Record, Abbrev);
1909   Record.clear();
1910 }
1911 
1912 void ModuleBitcodeWriter::writeDIMacroFile(const DIMacroFile *N,
1913                                            SmallVectorImpl<uint64_t> &Record,
1914                                            unsigned Abbrev) {
1915   Record.push_back(N->isDistinct());
1916   Record.push_back(N->getMacinfoType());
1917   Record.push_back(N->getLine());
1918   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1919   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1920 
1921   Stream.EmitRecord(bitc::METADATA_MACRO_FILE, Record, Abbrev);
1922   Record.clear();
1923 }
1924 
1925 void ModuleBitcodeWriter::writeDIArgList(const DIArgList *N,
1926                                          SmallVectorImpl<uint64_t> &Record,
1927                                          unsigned Abbrev) {
1928   Record.reserve(N->getArgs().size());
1929   for (ValueAsMetadata *MD : N->getArgs())
1930     Record.push_back(VE.getMetadataID(MD));
1931 
1932   Stream.EmitRecord(bitc::METADATA_ARG_LIST, Record, Abbrev);
1933   Record.clear();
1934 }
1935 
1936 void ModuleBitcodeWriter::writeDIModule(const DIModule *N,
1937                                         SmallVectorImpl<uint64_t> &Record,
1938                                         unsigned Abbrev) {
1939   Record.push_back(N->isDistinct());
1940   for (auto &I : N->operands())
1941     Record.push_back(VE.getMetadataOrNullID(I));
1942   Record.push_back(N->getLineNo());
1943   Record.push_back(N->getIsDecl());
1944 
1945   Stream.EmitRecord(bitc::METADATA_MODULE, Record, Abbrev);
1946   Record.clear();
1947 }
1948 
1949 void ModuleBitcodeWriter::writeDITemplateTypeParameter(
1950     const DITemplateTypeParameter *N, SmallVectorImpl<uint64_t> &Record,
1951     unsigned Abbrev) {
1952   Record.push_back(N->isDistinct());
1953   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1954   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1955   Record.push_back(N->isDefault());
1956 
1957   Stream.EmitRecord(bitc::METADATA_TEMPLATE_TYPE, Record, Abbrev);
1958   Record.clear();
1959 }
1960 
1961 void ModuleBitcodeWriter::writeDITemplateValueParameter(
1962     const DITemplateValueParameter *N, SmallVectorImpl<uint64_t> &Record,
1963     unsigned Abbrev) {
1964   Record.push_back(N->isDistinct());
1965   Record.push_back(N->getTag());
1966   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1967   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1968   Record.push_back(N->isDefault());
1969   Record.push_back(VE.getMetadataOrNullID(N->getValue()));
1970 
1971   Stream.EmitRecord(bitc::METADATA_TEMPLATE_VALUE, Record, Abbrev);
1972   Record.clear();
1973 }
1974 
1975 void ModuleBitcodeWriter::writeDIGlobalVariable(
1976     const DIGlobalVariable *N, SmallVectorImpl<uint64_t> &Record,
1977     unsigned Abbrev) {
1978   const uint64_t Version = 2 << 1;
1979   Record.push_back((uint64_t)N->isDistinct() | Version);
1980   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1981   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1982   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1983   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1984   Record.push_back(N->getLine());
1985   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1986   Record.push_back(N->isLocalToUnit());
1987   Record.push_back(N->isDefinition());
1988   Record.push_back(VE.getMetadataOrNullID(N->getStaticDataMemberDeclaration()));
1989   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams()));
1990   Record.push_back(N->getAlignInBits());
1991   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1992 
1993   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR, Record, Abbrev);
1994   Record.clear();
1995 }
1996 
1997 void ModuleBitcodeWriter::writeDILocalVariable(
1998     const DILocalVariable *N, SmallVectorImpl<uint64_t> &Record,
1999     unsigned Abbrev) {
2000   // In order to support all possible bitcode formats in BitcodeReader we need
2001   // to distinguish the following cases:
2002   // 1) Record has no artificial tag (Record[1]),
2003   //   has no obsolete inlinedAt field (Record[9]).
2004   //   In this case Record size will be 8, HasAlignment flag is false.
2005   // 2) Record has artificial tag (Record[1]),
2006   //   has no obsolete inlignedAt field (Record[9]).
2007   //   In this case Record size will be 9, HasAlignment flag is false.
2008   // 3) Record has both artificial tag (Record[1]) and
2009   //   obsolete inlignedAt field (Record[9]).
2010   //   In this case Record size will be 10, HasAlignment flag is false.
2011   // 4) Record has neither artificial tag, nor inlignedAt field, but
2012   //   HasAlignment flag is true and Record[8] contains alignment value.
2013   const uint64_t HasAlignmentFlag = 1 << 1;
2014   Record.push_back((uint64_t)N->isDistinct() | HasAlignmentFlag);
2015   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2016   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2017   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2018   Record.push_back(N->getLine());
2019   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2020   Record.push_back(N->getArg());
2021   Record.push_back(N->getFlags());
2022   Record.push_back(N->getAlignInBits());
2023   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
2024 
2025   Stream.EmitRecord(bitc::METADATA_LOCAL_VAR, Record, Abbrev);
2026   Record.clear();
2027 }
2028 
2029 void ModuleBitcodeWriter::writeDILabel(
2030     const DILabel *N, SmallVectorImpl<uint64_t> &Record,
2031     unsigned Abbrev) {
2032   Record.push_back((uint64_t)N->isDistinct());
2033   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2034   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2035   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2036   Record.push_back(N->getLine());
2037 
2038   Stream.EmitRecord(bitc::METADATA_LABEL, Record, Abbrev);
2039   Record.clear();
2040 }
2041 
2042 void ModuleBitcodeWriter::writeDIExpression(const DIExpression *N,
2043                                             SmallVectorImpl<uint64_t> &Record,
2044                                             unsigned Abbrev) {
2045   Record.reserve(N->getElements().size() + 1);
2046   const uint64_t Version = 3 << 1;
2047   Record.push_back((uint64_t)N->isDistinct() | Version);
2048   Record.append(N->elements_begin(), N->elements_end());
2049 
2050   Stream.EmitRecord(bitc::METADATA_EXPRESSION, Record, Abbrev);
2051   Record.clear();
2052 }
2053 
2054 void ModuleBitcodeWriter::writeDIGlobalVariableExpression(
2055     const DIGlobalVariableExpression *N, SmallVectorImpl<uint64_t> &Record,
2056     unsigned Abbrev) {
2057   Record.push_back(N->isDistinct());
2058   Record.push_back(VE.getMetadataOrNullID(N->getVariable()));
2059   Record.push_back(VE.getMetadataOrNullID(N->getExpression()));
2060 
2061   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR_EXPR, Record, Abbrev);
2062   Record.clear();
2063 }
2064 
2065 void ModuleBitcodeWriter::writeDIObjCProperty(const DIObjCProperty *N,
2066                                               SmallVectorImpl<uint64_t> &Record,
2067                                               unsigned Abbrev) {
2068   Record.push_back(N->isDistinct());
2069   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2070   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2071   Record.push_back(N->getLine());
2072   Record.push_back(VE.getMetadataOrNullID(N->getRawSetterName()));
2073   Record.push_back(VE.getMetadataOrNullID(N->getRawGetterName()));
2074   Record.push_back(N->getAttributes());
2075   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2076 
2077   Stream.EmitRecord(bitc::METADATA_OBJC_PROPERTY, Record, Abbrev);
2078   Record.clear();
2079 }
2080 
2081 void ModuleBitcodeWriter::writeDIImportedEntity(
2082     const DIImportedEntity *N, SmallVectorImpl<uint64_t> &Record,
2083     unsigned Abbrev) {
2084   Record.push_back(N->isDistinct());
2085   Record.push_back(N->getTag());
2086   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2087   Record.push_back(VE.getMetadataOrNullID(N->getEntity()));
2088   Record.push_back(N->getLine());
2089   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2090   Record.push_back(VE.getMetadataOrNullID(N->getRawFile()));
2091   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
2092 
2093   Stream.EmitRecord(bitc::METADATA_IMPORTED_ENTITY, Record, Abbrev);
2094   Record.clear();
2095 }
2096 
2097 unsigned ModuleBitcodeWriter::createNamedMetadataAbbrev() {
2098   auto Abbv = std::make_shared<BitCodeAbbrev>();
2099   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
2100   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2101   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2102   return Stream.EmitAbbrev(std::move(Abbv));
2103 }
2104 
2105 void ModuleBitcodeWriter::writeNamedMetadata(
2106     SmallVectorImpl<uint64_t> &Record) {
2107   if (M.named_metadata_empty())
2108     return;
2109 
2110   unsigned Abbrev = createNamedMetadataAbbrev();
2111   for (const NamedMDNode &NMD : M.named_metadata()) {
2112     // Write name.
2113     StringRef Str = NMD.getName();
2114     Record.append(Str.bytes_begin(), Str.bytes_end());
2115     Stream.EmitRecord(bitc::METADATA_NAME, Record, Abbrev);
2116     Record.clear();
2117 
2118     // Write named metadata operands.
2119     for (const MDNode *N : NMD.operands())
2120       Record.push_back(VE.getMetadataID(N));
2121     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
2122     Record.clear();
2123   }
2124 }
2125 
2126 unsigned ModuleBitcodeWriter::createMetadataStringsAbbrev() {
2127   auto Abbv = std::make_shared<BitCodeAbbrev>();
2128   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRINGS));
2129   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // # of strings
2130   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // offset to chars
2131   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
2132   return Stream.EmitAbbrev(std::move(Abbv));
2133 }
2134 
2135 /// Write out a record for MDString.
2136 ///
2137 /// All the metadata strings in a metadata block are emitted in a single
2138 /// record.  The sizes and strings themselves are shoved into a blob.
2139 void ModuleBitcodeWriter::writeMetadataStrings(
2140     ArrayRef<const Metadata *> Strings, SmallVectorImpl<uint64_t> &Record) {
2141   if (Strings.empty())
2142     return;
2143 
2144   // Start the record with the number of strings.
2145   Record.push_back(bitc::METADATA_STRINGS);
2146   Record.push_back(Strings.size());
2147 
2148   // Emit the sizes of the strings in the blob.
2149   SmallString<256> Blob;
2150   {
2151     BitstreamWriter W(Blob);
2152     for (const Metadata *MD : Strings)
2153       W.EmitVBR(cast<MDString>(MD)->getLength(), 6);
2154     W.FlushToWord();
2155   }
2156 
2157   // Add the offset to the strings to the record.
2158   Record.push_back(Blob.size());
2159 
2160   // Add the strings to the blob.
2161   for (const Metadata *MD : Strings)
2162     Blob.append(cast<MDString>(MD)->getString());
2163 
2164   // Emit the final record.
2165   Stream.EmitRecordWithBlob(createMetadataStringsAbbrev(), Record, Blob);
2166   Record.clear();
2167 }
2168 
2169 // Generates an enum to use as an index in the Abbrev array of Metadata record.
2170 enum MetadataAbbrev : unsigned {
2171 #define HANDLE_MDNODE_LEAF(CLASS) CLASS##AbbrevID,
2172 #include "llvm/IR/Metadata.def"
2173   LastPlusOne
2174 };
2175 
2176 void ModuleBitcodeWriter::writeMetadataRecords(
2177     ArrayRef<const Metadata *> MDs, SmallVectorImpl<uint64_t> &Record,
2178     std::vector<unsigned> *MDAbbrevs, std::vector<uint64_t> *IndexPos) {
2179   if (MDs.empty())
2180     return;
2181 
2182   // Initialize MDNode abbreviations.
2183 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
2184 #include "llvm/IR/Metadata.def"
2185 
2186   for (const Metadata *MD : MDs) {
2187     if (IndexPos)
2188       IndexPos->push_back(Stream.GetCurrentBitNo());
2189     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
2190       assert(N->isResolved() && "Expected forward references to be resolved");
2191 
2192       switch (N->getMetadataID()) {
2193       default:
2194         llvm_unreachable("Invalid MDNode subclass");
2195 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
2196   case Metadata::CLASS##Kind:                                                  \
2197     if (MDAbbrevs)                                                             \
2198       write##CLASS(cast<CLASS>(N), Record,                                     \
2199                    (*MDAbbrevs)[MetadataAbbrev::CLASS##AbbrevID]);             \
2200     else                                                                       \
2201       write##CLASS(cast<CLASS>(N), Record, CLASS##Abbrev);                     \
2202     continue;
2203 #include "llvm/IR/Metadata.def"
2204       }
2205     }
2206     writeValueAsMetadata(cast<ValueAsMetadata>(MD), Record);
2207   }
2208 }
2209 
2210 void ModuleBitcodeWriter::writeModuleMetadata() {
2211   if (!VE.hasMDs() && M.named_metadata_empty())
2212     return;
2213 
2214   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 4);
2215   SmallVector<uint64_t, 64> Record;
2216 
2217   // Emit all abbrevs upfront, so that the reader can jump in the middle of the
2218   // block and load any metadata.
2219   std::vector<unsigned> MDAbbrevs;
2220 
2221   MDAbbrevs.resize(MetadataAbbrev::LastPlusOne);
2222   MDAbbrevs[MetadataAbbrev::DILocationAbbrevID] = createDILocationAbbrev();
2223   MDAbbrevs[MetadataAbbrev::GenericDINodeAbbrevID] =
2224       createGenericDINodeAbbrev();
2225 
2226   auto Abbv = std::make_shared<BitCodeAbbrev>();
2227   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX_OFFSET));
2228   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2229   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2230   unsigned OffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2231 
2232   Abbv = std::make_shared<BitCodeAbbrev>();
2233   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX));
2234   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2235   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2236   unsigned IndexAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2237 
2238   // Emit MDStrings together upfront.
2239   writeMetadataStrings(VE.getMDStrings(), Record);
2240 
2241   // We only emit an index for the metadata record if we have more than a given
2242   // (naive) threshold of metadatas, otherwise it is not worth it.
2243   if (VE.getNonMDStrings().size() > IndexThreshold) {
2244     // Write a placeholder value in for the offset of the metadata index,
2245     // which is written after the records, so that it can include
2246     // the offset of each entry. The placeholder offset will be
2247     // updated after all records are emitted.
2248     uint64_t Vals[] = {0, 0};
2249     Stream.EmitRecord(bitc::METADATA_INDEX_OFFSET, Vals, OffsetAbbrev);
2250   }
2251 
2252   // Compute and save the bit offset to the current position, which will be
2253   // patched when we emit the index later. We can simply subtract the 64-bit
2254   // fixed size from the current bit number to get the location to backpatch.
2255   uint64_t IndexOffsetRecordBitPos = Stream.GetCurrentBitNo();
2256 
2257   // This index will contain the bitpos for each individual record.
2258   std::vector<uint64_t> IndexPos;
2259   IndexPos.reserve(VE.getNonMDStrings().size());
2260 
2261   // Write all the records
2262   writeMetadataRecords(VE.getNonMDStrings(), Record, &MDAbbrevs, &IndexPos);
2263 
2264   if (VE.getNonMDStrings().size() > IndexThreshold) {
2265     // Now that we have emitted all the records we will emit the index. But
2266     // first
2267     // backpatch the forward reference so that the reader can skip the records
2268     // efficiently.
2269     Stream.BackpatchWord64(IndexOffsetRecordBitPos - 64,
2270                            Stream.GetCurrentBitNo() - IndexOffsetRecordBitPos);
2271 
2272     // Delta encode the index.
2273     uint64_t PreviousValue = IndexOffsetRecordBitPos;
2274     for (auto &Elt : IndexPos) {
2275       auto EltDelta = Elt - PreviousValue;
2276       PreviousValue = Elt;
2277       Elt = EltDelta;
2278     }
2279     // Emit the index record.
2280     Stream.EmitRecord(bitc::METADATA_INDEX, IndexPos, IndexAbbrev);
2281     IndexPos.clear();
2282   }
2283 
2284   // Write the named metadata now.
2285   writeNamedMetadata(Record);
2286 
2287   auto AddDeclAttachedMetadata = [&](const GlobalObject &GO) {
2288     SmallVector<uint64_t, 4> Record;
2289     Record.push_back(VE.getValueID(&GO));
2290     pushGlobalMetadataAttachment(Record, GO);
2291     Stream.EmitRecord(bitc::METADATA_GLOBAL_DECL_ATTACHMENT, Record);
2292   };
2293   for (const Function &F : M)
2294     if (F.isDeclaration() && F.hasMetadata())
2295       AddDeclAttachedMetadata(F);
2296   // FIXME: Only store metadata for declarations here, and move data for global
2297   // variable definitions to a separate block (PR28134).
2298   for (const GlobalVariable &GV : M.globals())
2299     if (GV.hasMetadata())
2300       AddDeclAttachedMetadata(GV);
2301 
2302   Stream.ExitBlock();
2303 }
2304 
2305 void ModuleBitcodeWriter::writeFunctionMetadata(const Function &F) {
2306   if (!VE.hasMDs())
2307     return;
2308 
2309   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
2310   SmallVector<uint64_t, 64> Record;
2311   writeMetadataStrings(VE.getMDStrings(), Record);
2312   writeMetadataRecords(VE.getNonMDStrings(), Record);
2313   Stream.ExitBlock();
2314 }
2315 
2316 void ModuleBitcodeWriter::pushGlobalMetadataAttachment(
2317     SmallVectorImpl<uint64_t> &Record, const GlobalObject &GO) {
2318   // [n x [id, mdnode]]
2319   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2320   GO.getAllMetadata(MDs);
2321   for (const auto &I : MDs) {
2322     Record.push_back(I.first);
2323     Record.push_back(VE.getMetadataID(I.second));
2324   }
2325 }
2326 
2327 void ModuleBitcodeWriter::writeFunctionMetadataAttachment(const Function &F) {
2328   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
2329 
2330   SmallVector<uint64_t, 64> Record;
2331 
2332   if (F.hasMetadata()) {
2333     pushGlobalMetadataAttachment(Record, F);
2334     Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2335     Record.clear();
2336   }
2337 
2338   // Write metadata attachments
2339   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
2340   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2341   for (const BasicBlock &BB : F)
2342     for (const Instruction &I : BB) {
2343       MDs.clear();
2344       I.getAllMetadataOtherThanDebugLoc(MDs);
2345 
2346       // If no metadata, ignore instruction.
2347       if (MDs.empty()) continue;
2348 
2349       Record.push_back(VE.getInstructionID(&I));
2350 
2351       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
2352         Record.push_back(MDs[i].first);
2353         Record.push_back(VE.getMetadataID(MDs[i].second));
2354       }
2355       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2356       Record.clear();
2357     }
2358 
2359   Stream.ExitBlock();
2360 }
2361 
2362 void ModuleBitcodeWriter::writeModuleMetadataKinds() {
2363   SmallVector<uint64_t, 64> Record;
2364 
2365   // Write metadata kinds
2366   // METADATA_KIND - [n x [id, name]]
2367   SmallVector<StringRef, 8> Names;
2368   M.getMDKindNames(Names);
2369 
2370   if (Names.empty()) return;
2371 
2372   Stream.EnterSubblock(bitc::METADATA_KIND_BLOCK_ID, 3);
2373 
2374   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
2375     Record.push_back(MDKindID);
2376     StringRef KName = Names[MDKindID];
2377     Record.append(KName.begin(), KName.end());
2378 
2379     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
2380     Record.clear();
2381   }
2382 
2383   Stream.ExitBlock();
2384 }
2385 
2386 void ModuleBitcodeWriter::writeOperandBundleTags() {
2387   // Write metadata kinds
2388   //
2389   // OPERAND_BUNDLE_TAGS_BLOCK_ID : N x OPERAND_BUNDLE_TAG
2390   //
2391   // OPERAND_BUNDLE_TAG - [strchr x N]
2392 
2393   SmallVector<StringRef, 8> Tags;
2394   M.getOperandBundleTags(Tags);
2395 
2396   if (Tags.empty())
2397     return;
2398 
2399   Stream.EnterSubblock(bitc::OPERAND_BUNDLE_TAGS_BLOCK_ID, 3);
2400 
2401   SmallVector<uint64_t, 64> Record;
2402 
2403   for (auto Tag : Tags) {
2404     Record.append(Tag.begin(), Tag.end());
2405 
2406     Stream.EmitRecord(bitc::OPERAND_BUNDLE_TAG, Record, 0);
2407     Record.clear();
2408   }
2409 
2410   Stream.ExitBlock();
2411 }
2412 
2413 void ModuleBitcodeWriter::writeSyncScopeNames() {
2414   SmallVector<StringRef, 8> SSNs;
2415   M.getContext().getSyncScopeNames(SSNs);
2416   if (SSNs.empty())
2417     return;
2418 
2419   Stream.EnterSubblock(bitc::SYNC_SCOPE_NAMES_BLOCK_ID, 2);
2420 
2421   SmallVector<uint64_t, 64> Record;
2422   for (auto SSN : SSNs) {
2423     Record.append(SSN.begin(), SSN.end());
2424     Stream.EmitRecord(bitc::SYNC_SCOPE_NAME, Record, 0);
2425     Record.clear();
2426   }
2427 
2428   Stream.ExitBlock();
2429 }
2430 
2431 void ModuleBitcodeWriter::writeConstants(unsigned FirstVal, unsigned LastVal,
2432                                          bool isGlobal) {
2433   if (FirstVal == LastVal) return;
2434 
2435   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
2436 
2437   unsigned AggregateAbbrev = 0;
2438   unsigned String8Abbrev = 0;
2439   unsigned CString7Abbrev = 0;
2440   unsigned CString6Abbrev = 0;
2441   // If this is a constant pool for the module, emit module-specific abbrevs.
2442   if (isGlobal) {
2443     // Abbrev for CST_CODE_AGGREGATE.
2444     auto Abbv = std::make_shared<BitCodeAbbrev>();
2445     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
2446     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2447     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
2448     AggregateAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2449 
2450     // Abbrev for CST_CODE_STRING.
2451     Abbv = std::make_shared<BitCodeAbbrev>();
2452     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
2453     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2454     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2455     String8Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2456     // Abbrev for CST_CODE_CSTRING.
2457     Abbv = std::make_shared<BitCodeAbbrev>();
2458     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2459     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2460     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2461     CString7Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2462     // Abbrev for CST_CODE_CSTRING.
2463     Abbv = std::make_shared<BitCodeAbbrev>();
2464     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2465     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2466     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2467     CString6Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2468   }
2469 
2470   SmallVector<uint64_t, 64> Record;
2471 
2472   const ValueEnumerator::ValueList &Vals = VE.getValues();
2473   Type *LastTy = nullptr;
2474   for (unsigned i = FirstVal; i != LastVal; ++i) {
2475     const Value *V = Vals[i].first;
2476     // If we need to switch types, do so now.
2477     if (V->getType() != LastTy) {
2478       LastTy = V->getType();
2479       Record.push_back(VE.getTypeID(LastTy));
2480       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
2481                         CONSTANTS_SETTYPE_ABBREV);
2482       Record.clear();
2483     }
2484 
2485     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
2486       Record.push_back(VE.getTypeID(IA->getFunctionType()));
2487       Record.push_back(
2488           unsigned(IA->hasSideEffects()) | unsigned(IA->isAlignStack()) << 1 |
2489           unsigned(IA->getDialect() & 1) << 2 | unsigned(IA->canThrow()) << 3);
2490 
2491       // Add the asm string.
2492       const std::string &AsmStr = IA->getAsmString();
2493       Record.push_back(AsmStr.size());
2494       Record.append(AsmStr.begin(), AsmStr.end());
2495 
2496       // Add the constraint string.
2497       const std::string &ConstraintStr = IA->getConstraintString();
2498       Record.push_back(ConstraintStr.size());
2499       Record.append(ConstraintStr.begin(), ConstraintStr.end());
2500       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
2501       Record.clear();
2502       continue;
2503     }
2504     const Constant *C = cast<Constant>(V);
2505     unsigned Code = -1U;
2506     unsigned AbbrevToUse = 0;
2507     if (C->isNullValue()) {
2508       Code = bitc::CST_CODE_NULL;
2509     } else if (isa<PoisonValue>(C)) {
2510       Code = bitc::CST_CODE_POISON;
2511     } else if (isa<UndefValue>(C)) {
2512       Code = bitc::CST_CODE_UNDEF;
2513     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
2514       if (IV->getBitWidth() <= 64) {
2515         uint64_t V = IV->getSExtValue();
2516         emitSignedInt64(Record, V);
2517         Code = bitc::CST_CODE_INTEGER;
2518         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
2519       } else {                             // Wide integers, > 64 bits in size.
2520         emitWideAPInt(Record, IV->getValue());
2521         Code = bitc::CST_CODE_WIDE_INTEGER;
2522       }
2523     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
2524       Code = bitc::CST_CODE_FLOAT;
2525       Type *Ty = CFP->getType();
2526       if (Ty->isHalfTy() || Ty->isBFloatTy() || Ty->isFloatTy() ||
2527           Ty->isDoubleTy()) {
2528         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
2529       } else if (Ty->isX86_FP80Ty()) {
2530         // api needed to prevent premature destruction
2531         // bits are not in the same order as a normal i80 APInt, compensate.
2532         APInt api = CFP->getValueAPF().bitcastToAPInt();
2533         const uint64_t *p = api.getRawData();
2534         Record.push_back((p[1] << 48) | (p[0] >> 16));
2535         Record.push_back(p[0] & 0xffffLL);
2536       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
2537         APInt api = CFP->getValueAPF().bitcastToAPInt();
2538         const uint64_t *p = api.getRawData();
2539         Record.push_back(p[0]);
2540         Record.push_back(p[1]);
2541       } else {
2542         assert(0 && "Unknown FP type!");
2543       }
2544     } else if (isa<ConstantDataSequential>(C) &&
2545                cast<ConstantDataSequential>(C)->isString()) {
2546       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
2547       // Emit constant strings specially.
2548       unsigned NumElts = Str->getNumElements();
2549       // If this is a null-terminated string, use the denser CSTRING encoding.
2550       if (Str->isCString()) {
2551         Code = bitc::CST_CODE_CSTRING;
2552         --NumElts;  // Don't encode the null, which isn't allowed by char6.
2553       } else {
2554         Code = bitc::CST_CODE_STRING;
2555         AbbrevToUse = String8Abbrev;
2556       }
2557       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
2558       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
2559       for (unsigned i = 0; i != NumElts; ++i) {
2560         unsigned char V = Str->getElementAsInteger(i);
2561         Record.push_back(V);
2562         isCStr7 &= (V & 128) == 0;
2563         if (isCStrChar6)
2564           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
2565       }
2566 
2567       if (isCStrChar6)
2568         AbbrevToUse = CString6Abbrev;
2569       else if (isCStr7)
2570         AbbrevToUse = CString7Abbrev;
2571     } else if (const ConstantDataSequential *CDS =
2572                   dyn_cast<ConstantDataSequential>(C)) {
2573       Code = bitc::CST_CODE_DATA;
2574       Type *EltTy = CDS->getElementType();
2575       if (isa<IntegerType>(EltTy)) {
2576         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2577           Record.push_back(CDS->getElementAsInteger(i));
2578       } else {
2579         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2580           Record.push_back(
2581               CDS->getElementAsAPFloat(i).bitcastToAPInt().getLimitedValue());
2582       }
2583     } else if (isa<ConstantAggregate>(C)) {
2584       Code = bitc::CST_CODE_AGGREGATE;
2585       for (const Value *Op : C->operands())
2586         Record.push_back(VE.getValueID(Op));
2587       AbbrevToUse = AggregateAbbrev;
2588     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
2589       switch (CE->getOpcode()) {
2590       default:
2591         if (Instruction::isCast(CE->getOpcode())) {
2592           Code = bitc::CST_CODE_CE_CAST;
2593           Record.push_back(getEncodedCastOpcode(CE->getOpcode()));
2594           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2595           Record.push_back(VE.getValueID(C->getOperand(0)));
2596           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
2597         } else {
2598           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
2599           Code = bitc::CST_CODE_CE_BINOP;
2600           Record.push_back(getEncodedBinaryOpcode(CE->getOpcode()));
2601           Record.push_back(VE.getValueID(C->getOperand(0)));
2602           Record.push_back(VE.getValueID(C->getOperand(1)));
2603           uint64_t Flags = getOptimizationFlags(CE);
2604           if (Flags != 0)
2605             Record.push_back(Flags);
2606         }
2607         break;
2608       case Instruction::FNeg: {
2609         assert(CE->getNumOperands() == 1 && "Unknown constant expr!");
2610         Code = bitc::CST_CODE_CE_UNOP;
2611         Record.push_back(getEncodedUnaryOpcode(CE->getOpcode()));
2612         Record.push_back(VE.getValueID(C->getOperand(0)));
2613         uint64_t Flags = getOptimizationFlags(CE);
2614         if (Flags != 0)
2615           Record.push_back(Flags);
2616         break;
2617       }
2618       case Instruction::GetElementPtr: {
2619         Code = bitc::CST_CODE_CE_GEP;
2620         const auto *GO = cast<GEPOperator>(C);
2621         Record.push_back(VE.getTypeID(GO->getSourceElementType()));
2622         if (Optional<unsigned> Idx = GO->getInRangeIndex()) {
2623           Code = bitc::CST_CODE_CE_GEP_WITH_INRANGE_INDEX;
2624           Record.push_back((*Idx << 1) | GO->isInBounds());
2625         } else if (GO->isInBounds())
2626           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
2627         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
2628           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
2629           Record.push_back(VE.getValueID(C->getOperand(i)));
2630         }
2631         break;
2632       }
2633       case Instruction::Select:
2634         Code = bitc::CST_CODE_CE_SELECT;
2635         Record.push_back(VE.getValueID(C->getOperand(0)));
2636         Record.push_back(VE.getValueID(C->getOperand(1)));
2637         Record.push_back(VE.getValueID(C->getOperand(2)));
2638         break;
2639       case Instruction::ExtractElement:
2640         Code = bitc::CST_CODE_CE_EXTRACTELT;
2641         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2642         Record.push_back(VE.getValueID(C->getOperand(0)));
2643         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
2644         Record.push_back(VE.getValueID(C->getOperand(1)));
2645         break;
2646       case Instruction::InsertElement:
2647         Code = bitc::CST_CODE_CE_INSERTELT;
2648         Record.push_back(VE.getValueID(C->getOperand(0)));
2649         Record.push_back(VE.getValueID(C->getOperand(1)));
2650         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
2651         Record.push_back(VE.getValueID(C->getOperand(2)));
2652         break;
2653       case Instruction::ShuffleVector:
2654         // If the return type and argument types are the same, this is a
2655         // standard shufflevector instruction.  If the types are different,
2656         // then the shuffle is widening or truncating the input vectors, and
2657         // the argument type must also be encoded.
2658         if (C->getType() == C->getOperand(0)->getType()) {
2659           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
2660         } else {
2661           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
2662           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2663         }
2664         Record.push_back(VE.getValueID(C->getOperand(0)));
2665         Record.push_back(VE.getValueID(C->getOperand(1)));
2666         Record.push_back(VE.getValueID(CE->getShuffleMaskForBitcode()));
2667         break;
2668       case Instruction::ICmp:
2669       case Instruction::FCmp:
2670         Code = bitc::CST_CODE_CE_CMP;
2671         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2672         Record.push_back(VE.getValueID(C->getOperand(0)));
2673         Record.push_back(VE.getValueID(C->getOperand(1)));
2674         Record.push_back(CE->getPredicate());
2675         break;
2676       case Instruction::ExtractValue:
2677       case Instruction::InsertValue:
2678         report_fatal_error("extractvalue/insertvalue constexprs not supported");
2679         break;
2680       }
2681     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
2682       Code = bitc::CST_CODE_BLOCKADDRESS;
2683       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
2684       Record.push_back(VE.getValueID(BA->getFunction()));
2685       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
2686     } else if (const auto *Equiv = dyn_cast<DSOLocalEquivalent>(C)) {
2687       Code = bitc::CST_CODE_DSO_LOCAL_EQUIVALENT;
2688       Record.push_back(VE.getTypeID(Equiv->getGlobalValue()->getType()));
2689       Record.push_back(VE.getValueID(Equiv->getGlobalValue()));
2690     } else if (const auto *NC = dyn_cast<NoCFIValue>(C)) {
2691       Code = bitc::CST_CODE_NO_CFI_VALUE;
2692       Record.push_back(VE.getTypeID(NC->getGlobalValue()->getType()));
2693       Record.push_back(VE.getValueID(NC->getGlobalValue()));
2694     } else {
2695 #ifndef NDEBUG
2696       C->dump();
2697 #endif
2698       llvm_unreachable("Unknown constant!");
2699     }
2700     Stream.EmitRecord(Code, Record, AbbrevToUse);
2701     Record.clear();
2702   }
2703 
2704   Stream.ExitBlock();
2705 }
2706 
2707 void ModuleBitcodeWriter::writeModuleConstants() {
2708   const ValueEnumerator::ValueList &Vals = VE.getValues();
2709 
2710   // Find the first constant to emit, which is the first non-globalvalue value.
2711   // We know globalvalues have been emitted by WriteModuleInfo.
2712   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
2713     if (!isa<GlobalValue>(Vals[i].first)) {
2714       writeConstants(i, Vals.size(), true);
2715       return;
2716     }
2717   }
2718 }
2719 
2720 /// pushValueAndType - The file has to encode both the value and type id for
2721 /// many values, because we need to know what type to create for forward
2722 /// references.  However, most operands are not forward references, so this type
2723 /// field is not needed.
2724 ///
2725 /// This function adds V's value ID to Vals.  If the value ID is higher than the
2726 /// instruction ID, then it is a forward reference, and it also includes the
2727 /// type ID.  The value ID that is written is encoded relative to the InstID.
2728 bool ModuleBitcodeWriter::pushValueAndType(const Value *V, unsigned InstID,
2729                                            SmallVectorImpl<unsigned> &Vals) {
2730   unsigned ValID = VE.getValueID(V);
2731   // Make encoding relative to the InstID.
2732   Vals.push_back(InstID - ValID);
2733   if (ValID >= InstID) {
2734     Vals.push_back(VE.getTypeID(V->getType()));
2735     return true;
2736   }
2737   return false;
2738 }
2739 
2740 void ModuleBitcodeWriter::writeOperandBundles(const CallBase &CS,
2741                                               unsigned InstID) {
2742   SmallVector<unsigned, 64> Record;
2743   LLVMContext &C = CS.getContext();
2744 
2745   for (unsigned i = 0, e = CS.getNumOperandBundles(); i != e; ++i) {
2746     const auto &Bundle = CS.getOperandBundleAt(i);
2747     Record.push_back(C.getOperandBundleTagID(Bundle.getTagName()));
2748 
2749     for (auto &Input : Bundle.Inputs)
2750       pushValueAndType(Input, InstID, Record);
2751 
2752     Stream.EmitRecord(bitc::FUNC_CODE_OPERAND_BUNDLE, Record);
2753     Record.clear();
2754   }
2755 }
2756 
2757 /// pushValue - Like pushValueAndType, but where the type of the value is
2758 /// omitted (perhaps it was already encoded in an earlier operand).
2759 void ModuleBitcodeWriter::pushValue(const Value *V, unsigned InstID,
2760                                     SmallVectorImpl<unsigned> &Vals) {
2761   unsigned ValID = VE.getValueID(V);
2762   Vals.push_back(InstID - ValID);
2763 }
2764 
2765 void ModuleBitcodeWriter::pushValueSigned(const Value *V, unsigned InstID,
2766                                           SmallVectorImpl<uint64_t> &Vals) {
2767   unsigned ValID = VE.getValueID(V);
2768   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
2769   emitSignedInt64(Vals, diff);
2770 }
2771 
2772 /// WriteInstruction - Emit an instruction to the specified stream.
2773 void ModuleBitcodeWriter::writeInstruction(const Instruction &I,
2774                                            unsigned InstID,
2775                                            SmallVectorImpl<unsigned> &Vals) {
2776   unsigned Code = 0;
2777   unsigned AbbrevToUse = 0;
2778   VE.setInstructionID(&I);
2779   switch (I.getOpcode()) {
2780   default:
2781     if (Instruction::isCast(I.getOpcode())) {
2782       Code = bitc::FUNC_CODE_INST_CAST;
2783       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2784         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
2785       Vals.push_back(VE.getTypeID(I.getType()));
2786       Vals.push_back(getEncodedCastOpcode(I.getOpcode()));
2787     } else {
2788       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
2789       Code = bitc::FUNC_CODE_INST_BINOP;
2790       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2791         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
2792       pushValue(I.getOperand(1), InstID, Vals);
2793       Vals.push_back(getEncodedBinaryOpcode(I.getOpcode()));
2794       uint64_t Flags = getOptimizationFlags(&I);
2795       if (Flags != 0) {
2796         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
2797           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
2798         Vals.push_back(Flags);
2799       }
2800     }
2801     break;
2802   case Instruction::FNeg: {
2803     Code = bitc::FUNC_CODE_INST_UNOP;
2804     if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2805       AbbrevToUse = FUNCTION_INST_UNOP_ABBREV;
2806     Vals.push_back(getEncodedUnaryOpcode(I.getOpcode()));
2807     uint64_t Flags = getOptimizationFlags(&I);
2808     if (Flags != 0) {
2809       if (AbbrevToUse == FUNCTION_INST_UNOP_ABBREV)
2810         AbbrevToUse = FUNCTION_INST_UNOP_FLAGS_ABBREV;
2811       Vals.push_back(Flags);
2812     }
2813     break;
2814   }
2815   case Instruction::GetElementPtr: {
2816     Code = bitc::FUNC_CODE_INST_GEP;
2817     AbbrevToUse = FUNCTION_INST_GEP_ABBREV;
2818     auto &GEPInst = cast<GetElementPtrInst>(I);
2819     Vals.push_back(GEPInst.isInBounds());
2820     Vals.push_back(VE.getTypeID(GEPInst.getSourceElementType()));
2821     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
2822       pushValueAndType(I.getOperand(i), InstID, Vals);
2823     break;
2824   }
2825   case Instruction::ExtractValue: {
2826     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
2827     pushValueAndType(I.getOperand(0), InstID, Vals);
2828     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
2829     Vals.append(EVI->idx_begin(), EVI->idx_end());
2830     break;
2831   }
2832   case Instruction::InsertValue: {
2833     Code = bitc::FUNC_CODE_INST_INSERTVAL;
2834     pushValueAndType(I.getOperand(0), InstID, Vals);
2835     pushValueAndType(I.getOperand(1), InstID, Vals);
2836     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
2837     Vals.append(IVI->idx_begin(), IVI->idx_end());
2838     break;
2839   }
2840   case Instruction::Select: {
2841     Code = bitc::FUNC_CODE_INST_VSELECT;
2842     pushValueAndType(I.getOperand(1), InstID, Vals);
2843     pushValue(I.getOperand(2), InstID, Vals);
2844     pushValueAndType(I.getOperand(0), InstID, Vals);
2845     uint64_t Flags = getOptimizationFlags(&I);
2846     if (Flags != 0)
2847       Vals.push_back(Flags);
2848     break;
2849   }
2850   case Instruction::ExtractElement:
2851     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
2852     pushValueAndType(I.getOperand(0), InstID, Vals);
2853     pushValueAndType(I.getOperand(1), InstID, Vals);
2854     break;
2855   case Instruction::InsertElement:
2856     Code = bitc::FUNC_CODE_INST_INSERTELT;
2857     pushValueAndType(I.getOperand(0), InstID, Vals);
2858     pushValue(I.getOperand(1), InstID, Vals);
2859     pushValueAndType(I.getOperand(2), InstID, Vals);
2860     break;
2861   case Instruction::ShuffleVector:
2862     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
2863     pushValueAndType(I.getOperand(0), InstID, Vals);
2864     pushValue(I.getOperand(1), InstID, Vals);
2865     pushValue(cast<ShuffleVectorInst>(I).getShuffleMaskForBitcode(), InstID,
2866               Vals);
2867     break;
2868   case Instruction::ICmp:
2869   case Instruction::FCmp: {
2870     // compare returning Int1Ty or vector of Int1Ty
2871     Code = bitc::FUNC_CODE_INST_CMP2;
2872     pushValueAndType(I.getOperand(0), InstID, Vals);
2873     pushValue(I.getOperand(1), InstID, Vals);
2874     Vals.push_back(cast<CmpInst>(I).getPredicate());
2875     uint64_t Flags = getOptimizationFlags(&I);
2876     if (Flags != 0)
2877       Vals.push_back(Flags);
2878     break;
2879   }
2880 
2881   case Instruction::Ret:
2882     {
2883       Code = bitc::FUNC_CODE_INST_RET;
2884       unsigned NumOperands = I.getNumOperands();
2885       if (NumOperands == 0)
2886         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
2887       else if (NumOperands == 1) {
2888         if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2889           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
2890       } else {
2891         for (unsigned i = 0, e = NumOperands; i != e; ++i)
2892           pushValueAndType(I.getOperand(i), InstID, Vals);
2893       }
2894     }
2895     break;
2896   case Instruction::Br:
2897     {
2898       Code = bitc::FUNC_CODE_INST_BR;
2899       const BranchInst &II = cast<BranchInst>(I);
2900       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
2901       if (II.isConditional()) {
2902         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
2903         pushValue(II.getCondition(), InstID, Vals);
2904       }
2905     }
2906     break;
2907   case Instruction::Switch:
2908     {
2909       Code = bitc::FUNC_CODE_INST_SWITCH;
2910       const SwitchInst &SI = cast<SwitchInst>(I);
2911       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
2912       pushValue(SI.getCondition(), InstID, Vals);
2913       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
2914       for (auto Case : SI.cases()) {
2915         Vals.push_back(VE.getValueID(Case.getCaseValue()));
2916         Vals.push_back(VE.getValueID(Case.getCaseSuccessor()));
2917       }
2918     }
2919     break;
2920   case Instruction::IndirectBr:
2921     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
2922     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2923     // Encode the address operand as relative, but not the basic blocks.
2924     pushValue(I.getOperand(0), InstID, Vals);
2925     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
2926       Vals.push_back(VE.getValueID(I.getOperand(i)));
2927     break;
2928 
2929   case Instruction::Invoke: {
2930     const InvokeInst *II = cast<InvokeInst>(&I);
2931     const Value *Callee = II->getCalledOperand();
2932     FunctionType *FTy = II->getFunctionType();
2933 
2934     if (II->hasOperandBundles())
2935       writeOperandBundles(*II, InstID);
2936 
2937     Code = bitc::FUNC_CODE_INST_INVOKE;
2938 
2939     Vals.push_back(VE.getAttributeListID(II->getAttributes()));
2940     Vals.push_back(II->getCallingConv() | 1 << 13);
2941     Vals.push_back(VE.getValueID(II->getNormalDest()));
2942     Vals.push_back(VE.getValueID(II->getUnwindDest()));
2943     Vals.push_back(VE.getTypeID(FTy));
2944     pushValueAndType(Callee, InstID, Vals);
2945 
2946     // Emit value #'s for the fixed parameters.
2947     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
2948       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
2949 
2950     // Emit type/value pairs for varargs params.
2951     if (FTy->isVarArg()) {
2952       for (unsigned i = FTy->getNumParams(), e = II->arg_size(); i != e; ++i)
2953         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
2954     }
2955     break;
2956   }
2957   case Instruction::Resume:
2958     Code = bitc::FUNC_CODE_INST_RESUME;
2959     pushValueAndType(I.getOperand(0), InstID, Vals);
2960     break;
2961   case Instruction::CleanupRet: {
2962     Code = bitc::FUNC_CODE_INST_CLEANUPRET;
2963     const auto &CRI = cast<CleanupReturnInst>(I);
2964     pushValue(CRI.getCleanupPad(), InstID, Vals);
2965     if (CRI.hasUnwindDest())
2966       Vals.push_back(VE.getValueID(CRI.getUnwindDest()));
2967     break;
2968   }
2969   case Instruction::CatchRet: {
2970     Code = bitc::FUNC_CODE_INST_CATCHRET;
2971     const auto &CRI = cast<CatchReturnInst>(I);
2972     pushValue(CRI.getCatchPad(), InstID, Vals);
2973     Vals.push_back(VE.getValueID(CRI.getSuccessor()));
2974     break;
2975   }
2976   case Instruction::CleanupPad:
2977   case Instruction::CatchPad: {
2978     const auto &FuncletPad = cast<FuncletPadInst>(I);
2979     Code = isa<CatchPadInst>(FuncletPad) ? bitc::FUNC_CODE_INST_CATCHPAD
2980                                          : bitc::FUNC_CODE_INST_CLEANUPPAD;
2981     pushValue(FuncletPad.getParentPad(), InstID, Vals);
2982 
2983     unsigned NumArgOperands = FuncletPad.getNumArgOperands();
2984     Vals.push_back(NumArgOperands);
2985     for (unsigned Op = 0; Op != NumArgOperands; ++Op)
2986       pushValueAndType(FuncletPad.getArgOperand(Op), InstID, Vals);
2987     break;
2988   }
2989   case Instruction::CatchSwitch: {
2990     Code = bitc::FUNC_CODE_INST_CATCHSWITCH;
2991     const auto &CatchSwitch = cast<CatchSwitchInst>(I);
2992 
2993     pushValue(CatchSwitch.getParentPad(), InstID, Vals);
2994 
2995     unsigned NumHandlers = CatchSwitch.getNumHandlers();
2996     Vals.push_back(NumHandlers);
2997     for (const BasicBlock *CatchPadBB : CatchSwitch.handlers())
2998       Vals.push_back(VE.getValueID(CatchPadBB));
2999 
3000     if (CatchSwitch.hasUnwindDest())
3001       Vals.push_back(VE.getValueID(CatchSwitch.getUnwindDest()));
3002     break;
3003   }
3004   case Instruction::CallBr: {
3005     const CallBrInst *CBI = cast<CallBrInst>(&I);
3006     const Value *Callee = CBI->getCalledOperand();
3007     FunctionType *FTy = CBI->getFunctionType();
3008 
3009     if (CBI->hasOperandBundles())
3010       writeOperandBundles(*CBI, InstID);
3011 
3012     Code = bitc::FUNC_CODE_INST_CALLBR;
3013 
3014     Vals.push_back(VE.getAttributeListID(CBI->getAttributes()));
3015 
3016     Vals.push_back(CBI->getCallingConv() << bitc::CALL_CCONV |
3017                    1 << bitc::CALL_EXPLICIT_TYPE);
3018 
3019     Vals.push_back(VE.getValueID(CBI->getDefaultDest()));
3020     Vals.push_back(CBI->getNumIndirectDests());
3021     for (unsigned i = 0, e = CBI->getNumIndirectDests(); i != e; ++i)
3022       Vals.push_back(VE.getValueID(CBI->getIndirectDest(i)));
3023 
3024     Vals.push_back(VE.getTypeID(FTy));
3025     pushValueAndType(Callee, InstID, Vals);
3026 
3027     // Emit value #'s for the fixed parameters.
3028     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
3029       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
3030 
3031     // Emit type/value pairs for varargs params.
3032     if (FTy->isVarArg()) {
3033       for (unsigned i = FTy->getNumParams(), e = CBI->arg_size(); i != e; ++i)
3034         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
3035     }
3036     break;
3037   }
3038   case Instruction::Unreachable:
3039     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
3040     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
3041     break;
3042 
3043   case Instruction::PHI: {
3044     const PHINode &PN = cast<PHINode>(I);
3045     Code = bitc::FUNC_CODE_INST_PHI;
3046     // With the newer instruction encoding, forward references could give
3047     // negative valued IDs.  This is most common for PHIs, so we use
3048     // signed VBRs.
3049     SmallVector<uint64_t, 128> Vals64;
3050     Vals64.push_back(VE.getTypeID(PN.getType()));
3051     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
3052       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64);
3053       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
3054     }
3055 
3056     uint64_t Flags = getOptimizationFlags(&I);
3057     if (Flags != 0)
3058       Vals64.push_back(Flags);
3059 
3060     // Emit a Vals64 vector and exit.
3061     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
3062     Vals64.clear();
3063     return;
3064   }
3065 
3066   case Instruction::LandingPad: {
3067     const LandingPadInst &LP = cast<LandingPadInst>(I);
3068     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
3069     Vals.push_back(VE.getTypeID(LP.getType()));
3070     Vals.push_back(LP.isCleanup());
3071     Vals.push_back(LP.getNumClauses());
3072     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
3073       if (LP.isCatch(I))
3074         Vals.push_back(LandingPadInst::Catch);
3075       else
3076         Vals.push_back(LandingPadInst::Filter);
3077       pushValueAndType(LP.getClause(I), InstID, Vals);
3078     }
3079     break;
3080   }
3081 
3082   case Instruction::Alloca: {
3083     Code = bitc::FUNC_CODE_INST_ALLOCA;
3084     const AllocaInst &AI = cast<AllocaInst>(I);
3085     Vals.push_back(VE.getTypeID(AI.getAllocatedType()));
3086     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
3087     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
3088     using APV = AllocaPackedValues;
3089     unsigned Record = 0;
3090     unsigned EncodedAlign = getEncodedAlign(AI.getAlign());
3091     Bitfield::set<APV::AlignLower>(
3092         Record, EncodedAlign & ((1 << APV::AlignLower::Bits) - 1));
3093     Bitfield::set<APV::AlignUpper>(Record,
3094                                    EncodedAlign >> APV::AlignLower::Bits);
3095     Bitfield::set<APV::UsedWithInAlloca>(Record, AI.isUsedWithInAlloca());
3096     Bitfield::set<APV::ExplicitType>(Record, true);
3097     Bitfield::set<APV::SwiftError>(Record, AI.isSwiftError());
3098     Vals.push_back(Record);
3099 
3100     unsigned AS = AI.getAddressSpace();
3101     if (AS != M.getDataLayout().getAllocaAddrSpace())
3102       Vals.push_back(AS);
3103     break;
3104   }
3105 
3106   case Instruction::Load:
3107     if (cast<LoadInst>(I).isAtomic()) {
3108       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
3109       pushValueAndType(I.getOperand(0), InstID, Vals);
3110     } else {
3111       Code = bitc::FUNC_CODE_INST_LOAD;
3112       if (!pushValueAndType(I.getOperand(0), InstID, Vals)) // ptr
3113         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
3114     }
3115     Vals.push_back(VE.getTypeID(I.getType()));
3116     Vals.push_back(getEncodedAlign(cast<LoadInst>(I).getAlign()));
3117     Vals.push_back(cast<LoadInst>(I).isVolatile());
3118     if (cast<LoadInst>(I).isAtomic()) {
3119       Vals.push_back(getEncodedOrdering(cast<LoadInst>(I).getOrdering()));
3120       Vals.push_back(getEncodedSyncScopeID(cast<LoadInst>(I).getSyncScopeID()));
3121     }
3122     break;
3123   case Instruction::Store:
3124     if (cast<StoreInst>(I).isAtomic())
3125       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
3126     else
3127       Code = bitc::FUNC_CODE_INST_STORE;
3128     pushValueAndType(I.getOperand(1), InstID, Vals); // ptrty + ptr
3129     pushValueAndType(I.getOperand(0), InstID, Vals); // valty + val
3130     Vals.push_back(getEncodedAlign(cast<StoreInst>(I).getAlign()));
3131     Vals.push_back(cast<StoreInst>(I).isVolatile());
3132     if (cast<StoreInst>(I).isAtomic()) {
3133       Vals.push_back(getEncodedOrdering(cast<StoreInst>(I).getOrdering()));
3134       Vals.push_back(
3135           getEncodedSyncScopeID(cast<StoreInst>(I).getSyncScopeID()));
3136     }
3137     break;
3138   case Instruction::AtomicCmpXchg:
3139     Code = bitc::FUNC_CODE_INST_CMPXCHG;
3140     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
3141     pushValueAndType(I.getOperand(1), InstID, Vals); // cmp.
3142     pushValue(I.getOperand(2), InstID, Vals);        // newval.
3143     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
3144     Vals.push_back(
3145         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
3146     Vals.push_back(
3147         getEncodedSyncScopeID(cast<AtomicCmpXchgInst>(I).getSyncScopeID()));
3148     Vals.push_back(
3149         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
3150     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
3151     Vals.push_back(getEncodedAlign(cast<AtomicCmpXchgInst>(I).getAlign()));
3152     break;
3153   case Instruction::AtomicRMW:
3154     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
3155     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
3156     pushValueAndType(I.getOperand(1), InstID, Vals); // valty + val
3157     Vals.push_back(
3158         getEncodedRMWOperation(cast<AtomicRMWInst>(I).getOperation()));
3159     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
3160     Vals.push_back(getEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
3161     Vals.push_back(
3162         getEncodedSyncScopeID(cast<AtomicRMWInst>(I).getSyncScopeID()));
3163     Vals.push_back(getEncodedAlign(cast<AtomicRMWInst>(I).getAlign()));
3164     break;
3165   case Instruction::Fence:
3166     Code = bitc::FUNC_CODE_INST_FENCE;
3167     Vals.push_back(getEncodedOrdering(cast<FenceInst>(I).getOrdering()));
3168     Vals.push_back(getEncodedSyncScopeID(cast<FenceInst>(I).getSyncScopeID()));
3169     break;
3170   case Instruction::Call: {
3171     const CallInst &CI = cast<CallInst>(I);
3172     FunctionType *FTy = CI.getFunctionType();
3173 
3174     if (CI.hasOperandBundles())
3175       writeOperandBundles(CI, InstID);
3176 
3177     Code = bitc::FUNC_CODE_INST_CALL;
3178 
3179     Vals.push_back(VE.getAttributeListID(CI.getAttributes()));
3180 
3181     unsigned Flags = getOptimizationFlags(&I);
3182     Vals.push_back(CI.getCallingConv() << bitc::CALL_CCONV |
3183                    unsigned(CI.isTailCall()) << bitc::CALL_TAIL |
3184                    unsigned(CI.isMustTailCall()) << bitc::CALL_MUSTTAIL |
3185                    1 << bitc::CALL_EXPLICIT_TYPE |
3186                    unsigned(CI.isNoTailCall()) << bitc::CALL_NOTAIL |
3187                    unsigned(Flags != 0) << bitc::CALL_FMF);
3188     if (Flags != 0)
3189       Vals.push_back(Flags);
3190 
3191     Vals.push_back(VE.getTypeID(FTy));
3192     pushValueAndType(CI.getCalledOperand(), InstID, Vals); // Callee
3193 
3194     // Emit value #'s for the fixed parameters.
3195     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
3196       // Check for labels (can happen with asm labels).
3197       if (FTy->getParamType(i)->isLabelTy())
3198         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
3199       else
3200         pushValue(CI.getArgOperand(i), InstID, Vals); // fixed param.
3201     }
3202 
3203     // Emit type/value pairs for varargs params.
3204     if (FTy->isVarArg()) {
3205       for (unsigned i = FTy->getNumParams(), e = CI.arg_size(); i != e; ++i)
3206         pushValueAndType(CI.getArgOperand(i), InstID, Vals); // varargs
3207     }
3208     break;
3209   }
3210   case Instruction::VAArg:
3211     Code = bitc::FUNC_CODE_INST_VAARG;
3212     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
3213     pushValue(I.getOperand(0), InstID, Vals);                   // valist.
3214     Vals.push_back(VE.getTypeID(I.getType())); // restype.
3215     break;
3216   case Instruction::Freeze:
3217     Code = bitc::FUNC_CODE_INST_FREEZE;
3218     pushValueAndType(I.getOperand(0), InstID, Vals);
3219     break;
3220   }
3221 
3222   Stream.EmitRecord(Code, Vals, AbbrevToUse);
3223   Vals.clear();
3224 }
3225 
3226 /// Write a GlobalValue VST to the module. The purpose of this data structure is
3227 /// to allow clients to efficiently find the function body.
3228 void ModuleBitcodeWriter::writeGlobalValueSymbolTable(
3229   DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3230   // Get the offset of the VST we are writing, and backpatch it into
3231   // the VST forward declaration record.
3232   uint64_t VSTOffset = Stream.GetCurrentBitNo();
3233   // The BitcodeStartBit was the stream offset of the identification block.
3234   VSTOffset -= bitcodeStartBit();
3235   assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
3236   // Note that we add 1 here because the offset is relative to one word
3237   // before the start of the identification block, which was historically
3238   // always the start of the regular bitcode header.
3239   Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32 + 1);
3240 
3241   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3242 
3243   auto Abbv = std::make_shared<BitCodeAbbrev>();
3244   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
3245   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
3246   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
3247   unsigned FnEntryAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3248 
3249   for (const Function &F : M) {
3250     uint64_t Record[2];
3251 
3252     if (F.isDeclaration())
3253       continue;
3254 
3255     Record[0] = VE.getValueID(&F);
3256 
3257     // Save the word offset of the function (from the start of the
3258     // actual bitcode written to the stream).
3259     uint64_t BitcodeIndex = FunctionToBitcodeIndex[&F] - bitcodeStartBit();
3260     assert((BitcodeIndex & 31) == 0 && "function block not 32-bit aligned");
3261     // Note that we add 1 here because the offset is relative to one word
3262     // before the start of the identification block, which was historically
3263     // always the start of the regular bitcode header.
3264     Record[1] = BitcodeIndex / 32 + 1;
3265 
3266     Stream.EmitRecord(bitc::VST_CODE_FNENTRY, Record, FnEntryAbbrev);
3267   }
3268 
3269   Stream.ExitBlock();
3270 }
3271 
3272 /// Emit names for arguments, instructions and basic blocks in a function.
3273 void ModuleBitcodeWriter::writeFunctionLevelValueSymbolTable(
3274     const ValueSymbolTable &VST) {
3275   if (VST.empty())
3276     return;
3277 
3278   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3279 
3280   // FIXME: Set up the abbrev, we know how many values there are!
3281   // FIXME: We know if the type names can use 7-bit ascii.
3282   SmallVector<uint64_t, 64> NameVals;
3283 
3284   for (const ValueName &Name : VST) {
3285     // Figure out the encoding to use for the name.
3286     StringEncoding Bits = getStringEncoding(Name.getKey());
3287 
3288     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
3289     NameVals.push_back(VE.getValueID(Name.getValue()));
3290 
3291     // VST_CODE_ENTRY:   [valueid, namechar x N]
3292     // VST_CODE_BBENTRY: [bbid, namechar x N]
3293     unsigned Code;
3294     if (isa<BasicBlock>(Name.getValue())) {
3295       Code = bitc::VST_CODE_BBENTRY;
3296       if (Bits == SE_Char6)
3297         AbbrevToUse = VST_BBENTRY_6_ABBREV;
3298     } else {
3299       Code = bitc::VST_CODE_ENTRY;
3300       if (Bits == SE_Char6)
3301         AbbrevToUse = VST_ENTRY_6_ABBREV;
3302       else if (Bits == SE_Fixed7)
3303         AbbrevToUse = VST_ENTRY_7_ABBREV;
3304     }
3305 
3306     for (const auto P : Name.getKey())
3307       NameVals.push_back((unsigned char)P);
3308 
3309     // Emit the finished record.
3310     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
3311     NameVals.clear();
3312   }
3313 
3314   Stream.ExitBlock();
3315 }
3316 
3317 void ModuleBitcodeWriter::writeUseList(UseListOrder &&Order) {
3318   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
3319   unsigned Code;
3320   if (isa<BasicBlock>(Order.V))
3321     Code = bitc::USELIST_CODE_BB;
3322   else
3323     Code = bitc::USELIST_CODE_DEFAULT;
3324 
3325   SmallVector<uint64_t, 64> Record(Order.Shuffle.begin(), Order.Shuffle.end());
3326   Record.push_back(VE.getValueID(Order.V));
3327   Stream.EmitRecord(Code, Record);
3328 }
3329 
3330 void ModuleBitcodeWriter::writeUseListBlock(const Function *F) {
3331   assert(VE.shouldPreserveUseListOrder() &&
3332          "Expected to be preserving use-list order");
3333 
3334   auto hasMore = [&]() {
3335     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
3336   };
3337   if (!hasMore())
3338     // Nothing to do.
3339     return;
3340 
3341   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
3342   while (hasMore()) {
3343     writeUseList(std::move(VE.UseListOrders.back()));
3344     VE.UseListOrders.pop_back();
3345   }
3346   Stream.ExitBlock();
3347 }
3348 
3349 /// Emit a function body to the module stream.
3350 void ModuleBitcodeWriter::writeFunction(
3351     const Function &F,
3352     DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3353   // Save the bitcode index of the start of this function block for recording
3354   // in the VST.
3355   FunctionToBitcodeIndex[&F] = Stream.GetCurrentBitNo();
3356 
3357   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
3358   VE.incorporateFunction(F);
3359 
3360   SmallVector<unsigned, 64> Vals;
3361 
3362   // Emit the number of basic blocks, so the reader can create them ahead of
3363   // time.
3364   Vals.push_back(VE.getBasicBlocks().size());
3365   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
3366   Vals.clear();
3367 
3368   // If there are function-local constants, emit them now.
3369   unsigned CstStart, CstEnd;
3370   VE.getFunctionConstantRange(CstStart, CstEnd);
3371   writeConstants(CstStart, CstEnd, false);
3372 
3373   // If there is function-local metadata, emit it now.
3374   writeFunctionMetadata(F);
3375 
3376   // Keep a running idea of what the instruction ID is.
3377   unsigned InstID = CstEnd;
3378 
3379   bool NeedsMetadataAttachment = F.hasMetadata();
3380 
3381   DILocation *LastDL = nullptr;
3382   SmallSetVector<Function *, 4> BlockAddressUsers;
3383 
3384   // Finally, emit all the instructions, in order.
3385   for (const BasicBlock &BB : F) {
3386     for (const Instruction &I : BB) {
3387       writeInstruction(I, InstID, Vals);
3388 
3389       if (!I.getType()->isVoidTy())
3390         ++InstID;
3391 
3392       // If the instruction has metadata, write a metadata attachment later.
3393       NeedsMetadataAttachment |= I.hasMetadataOtherThanDebugLoc();
3394 
3395       // If the instruction has a debug location, emit it.
3396       DILocation *DL = I.getDebugLoc();
3397       if (!DL)
3398         continue;
3399 
3400       if (DL == LastDL) {
3401         // Just repeat the same debug loc as last time.
3402         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
3403         continue;
3404       }
3405 
3406       Vals.push_back(DL->getLine());
3407       Vals.push_back(DL->getColumn());
3408       Vals.push_back(VE.getMetadataOrNullID(DL->getScope()));
3409       Vals.push_back(VE.getMetadataOrNullID(DL->getInlinedAt()));
3410       Vals.push_back(DL->isImplicitCode());
3411       Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
3412       Vals.clear();
3413 
3414       LastDL = DL;
3415     }
3416 
3417     if (BlockAddress *BA = BlockAddress::lookup(&BB)) {
3418       SmallVector<Value *> Worklist{BA};
3419       SmallPtrSet<Value *, 8> Visited{BA};
3420       while (!Worklist.empty()) {
3421         Value *V = Worklist.pop_back_val();
3422         for (User *U : V->users()) {
3423           if (auto *I = dyn_cast<Instruction>(U)) {
3424             Function *P = I->getFunction();
3425             if (P != &F)
3426               BlockAddressUsers.insert(P);
3427           } else if (isa<Constant>(U) && !isa<GlobalValue>(U) &&
3428                      Visited.insert(U).second)
3429             Worklist.push_back(U);
3430         }
3431       }
3432     }
3433   }
3434 
3435   if (!BlockAddressUsers.empty()) {
3436     Vals.resize(BlockAddressUsers.size());
3437     for (auto I : llvm::enumerate(BlockAddressUsers))
3438       Vals[I.index()] = VE.getValueID(I.value());
3439     Stream.EmitRecord(bitc::FUNC_CODE_BLOCKADDR_USERS, Vals);
3440     Vals.clear();
3441   }
3442 
3443   // Emit names for all the instructions etc.
3444   if (auto *Symtab = F.getValueSymbolTable())
3445     writeFunctionLevelValueSymbolTable(*Symtab);
3446 
3447   if (NeedsMetadataAttachment)
3448     writeFunctionMetadataAttachment(F);
3449   if (VE.shouldPreserveUseListOrder())
3450     writeUseListBlock(&F);
3451   VE.purgeFunction();
3452   Stream.ExitBlock();
3453 }
3454 
3455 // Emit blockinfo, which defines the standard abbreviations etc.
3456 void ModuleBitcodeWriter::writeBlockInfo() {
3457   // We only want to emit block info records for blocks that have multiple
3458   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
3459   // Other blocks can define their abbrevs inline.
3460   Stream.EnterBlockInfoBlock();
3461 
3462   { // 8-bit fixed-width VST_CODE_ENTRY/VST_CODE_BBENTRY strings.
3463     auto Abbv = std::make_shared<BitCodeAbbrev>();
3464     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
3465     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3466     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3467     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3468     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3469         VST_ENTRY_8_ABBREV)
3470       llvm_unreachable("Unexpected abbrev ordering!");
3471   }
3472 
3473   { // 7-bit fixed width VST_CODE_ENTRY strings.
3474     auto Abbv = std::make_shared<BitCodeAbbrev>();
3475     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3476     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3477     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3478     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3479     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3480         VST_ENTRY_7_ABBREV)
3481       llvm_unreachable("Unexpected abbrev ordering!");
3482   }
3483   { // 6-bit char6 VST_CODE_ENTRY strings.
3484     auto Abbv = std::make_shared<BitCodeAbbrev>();
3485     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3486     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3487     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3488     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3489     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3490         VST_ENTRY_6_ABBREV)
3491       llvm_unreachable("Unexpected abbrev ordering!");
3492   }
3493   { // 6-bit char6 VST_CODE_BBENTRY strings.
3494     auto Abbv = std::make_shared<BitCodeAbbrev>();
3495     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
3496     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3497     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3498     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3499     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3500         VST_BBENTRY_6_ABBREV)
3501       llvm_unreachable("Unexpected abbrev ordering!");
3502   }
3503 
3504   { // SETTYPE abbrev for CONSTANTS_BLOCK.
3505     auto Abbv = std::make_shared<BitCodeAbbrev>();
3506     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
3507     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
3508                               VE.computeBitsRequiredForTypeIndicies()));
3509     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3510         CONSTANTS_SETTYPE_ABBREV)
3511       llvm_unreachable("Unexpected abbrev ordering!");
3512   }
3513 
3514   { // INTEGER abbrev for CONSTANTS_BLOCK.
3515     auto Abbv = std::make_shared<BitCodeAbbrev>();
3516     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
3517     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3518     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3519         CONSTANTS_INTEGER_ABBREV)
3520       llvm_unreachable("Unexpected abbrev ordering!");
3521   }
3522 
3523   { // CE_CAST abbrev for CONSTANTS_BLOCK.
3524     auto Abbv = std::make_shared<BitCodeAbbrev>();
3525     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
3526     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
3527     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
3528                               VE.computeBitsRequiredForTypeIndicies()));
3529     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
3530 
3531     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3532         CONSTANTS_CE_CAST_Abbrev)
3533       llvm_unreachable("Unexpected abbrev ordering!");
3534   }
3535   { // NULL abbrev for CONSTANTS_BLOCK.
3536     auto Abbv = std::make_shared<BitCodeAbbrev>();
3537     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
3538     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3539         CONSTANTS_NULL_Abbrev)
3540       llvm_unreachable("Unexpected abbrev ordering!");
3541   }
3542 
3543   // FIXME: This should only use space for first class types!
3544 
3545   { // INST_LOAD abbrev for FUNCTION_BLOCK.
3546     auto Abbv = std::make_shared<BitCodeAbbrev>();
3547     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
3548     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
3549     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
3550                               VE.computeBitsRequiredForTypeIndicies()));
3551     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
3552     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
3553     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3554         FUNCTION_INST_LOAD_ABBREV)
3555       llvm_unreachable("Unexpected abbrev ordering!");
3556   }
3557   { // INST_UNOP abbrev for FUNCTION_BLOCK.
3558     auto Abbv = std::make_shared<BitCodeAbbrev>();
3559     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3560     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3561     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3562     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3563         FUNCTION_INST_UNOP_ABBREV)
3564       llvm_unreachable("Unexpected abbrev ordering!");
3565   }
3566   { // INST_UNOP_FLAGS abbrev for FUNCTION_BLOCK.
3567     auto Abbv = std::make_shared<BitCodeAbbrev>();
3568     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3569     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3570     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3571     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3572     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3573         FUNCTION_INST_UNOP_FLAGS_ABBREV)
3574       llvm_unreachable("Unexpected abbrev ordering!");
3575   }
3576   { // INST_BINOP abbrev for FUNCTION_BLOCK.
3577     auto Abbv = std::make_shared<BitCodeAbbrev>();
3578     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3579     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3580     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3581     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3582     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3583         FUNCTION_INST_BINOP_ABBREV)
3584       llvm_unreachable("Unexpected abbrev ordering!");
3585   }
3586   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
3587     auto Abbv = std::make_shared<BitCodeAbbrev>();
3588     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3589     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3590     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3591     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3592     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3593     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3594         FUNCTION_INST_BINOP_FLAGS_ABBREV)
3595       llvm_unreachable("Unexpected abbrev ordering!");
3596   }
3597   { // INST_CAST abbrev for FUNCTION_BLOCK.
3598     auto Abbv = std::make_shared<BitCodeAbbrev>();
3599     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
3600     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
3601     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
3602                               VE.computeBitsRequiredForTypeIndicies()));
3603     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
3604     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3605         FUNCTION_INST_CAST_ABBREV)
3606       llvm_unreachable("Unexpected abbrev ordering!");
3607   }
3608 
3609   { // INST_RET abbrev for FUNCTION_BLOCK.
3610     auto Abbv = std::make_shared<BitCodeAbbrev>();
3611     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3612     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3613         FUNCTION_INST_RET_VOID_ABBREV)
3614       llvm_unreachable("Unexpected abbrev ordering!");
3615   }
3616   { // INST_RET abbrev for FUNCTION_BLOCK.
3617     auto Abbv = std::make_shared<BitCodeAbbrev>();
3618     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3619     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
3620     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3621         FUNCTION_INST_RET_VAL_ABBREV)
3622       llvm_unreachable("Unexpected abbrev ordering!");
3623   }
3624   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
3625     auto Abbv = std::make_shared<BitCodeAbbrev>();
3626     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
3627     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3628         FUNCTION_INST_UNREACHABLE_ABBREV)
3629       llvm_unreachable("Unexpected abbrev ordering!");
3630   }
3631   {
3632     auto Abbv = std::make_shared<BitCodeAbbrev>();
3633     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_GEP));
3634     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
3635     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, // dest ty
3636                               Log2_32_Ceil(VE.getTypes().size() + 1)));
3637     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3638     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
3639     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3640         FUNCTION_INST_GEP_ABBREV)
3641       llvm_unreachable("Unexpected abbrev ordering!");
3642   }
3643 
3644   Stream.ExitBlock();
3645 }
3646 
3647 /// Write the module path strings, currently only used when generating
3648 /// a combined index file.
3649 void IndexBitcodeWriter::writeModStrings() {
3650   Stream.EnterSubblock(bitc::MODULE_STRTAB_BLOCK_ID, 3);
3651 
3652   // TODO: See which abbrev sizes we actually need to emit
3653 
3654   // 8-bit fixed-width MST_ENTRY strings.
3655   auto Abbv = std::make_shared<BitCodeAbbrev>();
3656   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3657   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3658   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3659   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3660   unsigned Abbrev8Bit = Stream.EmitAbbrev(std::move(Abbv));
3661 
3662   // 7-bit fixed width MST_ENTRY strings.
3663   Abbv = std::make_shared<BitCodeAbbrev>();
3664   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3665   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3666   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3667   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3668   unsigned Abbrev7Bit = Stream.EmitAbbrev(std::move(Abbv));
3669 
3670   // 6-bit char6 MST_ENTRY strings.
3671   Abbv = std::make_shared<BitCodeAbbrev>();
3672   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3673   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3674   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3675   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3676   unsigned Abbrev6Bit = Stream.EmitAbbrev(std::move(Abbv));
3677 
3678   // Module Hash, 160 bits SHA1. Optionally, emitted after each MST_CODE_ENTRY.
3679   Abbv = std::make_shared<BitCodeAbbrev>();
3680   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_HASH));
3681   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3682   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3683   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3684   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3685   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3686   unsigned AbbrevHash = Stream.EmitAbbrev(std::move(Abbv));
3687 
3688   SmallVector<unsigned, 64> Vals;
3689   forEachModule(
3690       [&](const StringMapEntry<std::pair<uint64_t, ModuleHash>> &MPSE) {
3691         StringRef Key = MPSE.getKey();
3692         const auto &Value = MPSE.getValue();
3693         StringEncoding Bits = getStringEncoding(Key);
3694         unsigned AbbrevToUse = Abbrev8Bit;
3695         if (Bits == SE_Char6)
3696           AbbrevToUse = Abbrev6Bit;
3697         else if (Bits == SE_Fixed7)
3698           AbbrevToUse = Abbrev7Bit;
3699 
3700         Vals.push_back(Value.first);
3701         Vals.append(Key.begin(), Key.end());
3702 
3703         // Emit the finished record.
3704         Stream.EmitRecord(bitc::MST_CODE_ENTRY, Vals, AbbrevToUse);
3705 
3706         // Emit an optional hash for the module now
3707         const auto &Hash = Value.second;
3708         if (llvm::any_of(Hash, [](uint32_t H) { return H; })) {
3709           Vals.assign(Hash.begin(), Hash.end());
3710           // Emit the hash record.
3711           Stream.EmitRecord(bitc::MST_CODE_HASH, Vals, AbbrevHash);
3712         }
3713 
3714         Vals.clear();
3715       });
3716   Stream.ExitBlock();
3717 }
3718 
3719 /// Write the function type metadata related records that need to appear before
3720 /// a function summary entry (whether per-module or combined).
3721 template <typename Fn>
3722 static void writeFunctionTypeMetadataRecords(BitstreamWriter &Stream,
3723                                              FunctionSummary *FS,
3724                                              Fn GetValueID) {
3725   if (!FS->type_tests().empty())
3726     Stream.EmitRecord(bitc::FS_TYPE_TESTS, FS->type_tests());
3727 
3728   SmallVector<uint64_t, 64> Record;
3729 
3730   auto WriteVFuncIdVec = [&](uint64_t Ty,
3731                              ArrayRef<FunctionSummary::VFuncId> VFs) {
3732     if (VFs.empty())
3733       return;
3734     Record.clear();
3735     for (auto &VF : VFs) {
3736       Record.push_back(VF.GUID);
3737       Record.push_back(VF.Offset);
3738     }
3739     Stream.EmitRecord(Ty, Record);
3740   };
3741 
3742   WriteVFuncIdVec(bitc::FS_TYPE_TEST_ASSUME_VCALLS,
3743                   FS->type_test_assume_vcalls());
3744   WriteVFuncIdVec(bitc::FS_TYPE_CHECKED_LOAD_VCALLS,
3745                   FS->type_checked_load_vcalls());
3746 
3747   auto WriteConstVCallVec = [&](uint64_t Ty,
3748                                 ArrayRef<FunctionSummary::ConstVCall> VCs) {
3749     for (auto &VC : VCs) {
3750       Record.clear();
3751       Record.push_back(VC.VFunc.GUID);
3752       Record.push_back(VC.VFunc.Offset);
3753       llvm::append_range(Record, VC.Args);
3754       Stream.EmitRecord(Ty, Record);
3755     }
3756   };
3757 
3758   WriteConstVCallVec(bitc::FS_TYPE_TEST_ASSUME_CONST_VCALL,
3759                      FS->type_test_assume_const_vcalls());
3760   WriteConstVCallVec(bitc::FS_TYPE_CHECKED_LOAD_CONST_VCALL,
3761                      FS->type_checked_load_const_vcalls());
3762 
3763   auto WriteRange = [&](ConstantRange Range) {
3764     Range = Range.sextOrTrunc(FunctionSummary::ParamAccess::RangeWidth);
3765     assert(Range.getLower().getNumWords() == 1);
3766     assert(Range.getUpper().getNumWords() == 1);
3767     emitSignedInt64(Record, *Range.getLower().getRawData());
3768     emitSignedInt64(Record, *Range.getUpper().getRawData());
3769   };
3770 
3771   if (!FS->paramAccesses().empty()) {
3772     Record.clear();
3773     for (auto &Arg : FS->paramAccesses()) {
3774       size_t UndoSize = Record.size();
3775       Record.push_back(Arg.ParamNo);
3776       WriteRange(Arg.Use);
3777       Record.push_back(Arg.Calls.size());
3778       for (auto &Call : Arg.Calls) {
3779         Record.push_back(Call.ParamNo);
3780         Optional<unsigned> ValueID = GetValueID(Call.Callee);
3781         if (!ValueID) {
3782           // If ValueID is unknown we can't drop just this call, we must drop
3783           // entire parameter.
3784           Record.resize(UndoSize);
3785           break;
3786         }
3787         Record.push_back(*ValueID);
3788         WriteRange(Call.Offsets);
3789       }
3790     }
3791     if (!Record.empty())
3792       Stream.EmitRecord(bitc::FS_PARAM_ACCESS, Record);
3793   }
3794 }
3795 
3796 /// Collect type IDs from type tests used by function.
3797 static void
3798 getReferencedTypeIds(FunctionSummary *FS,
3799                      std::set<GlobalValue::GUID> &ReferencedTypeIds) {
3800   if (!FS->type_tests().empty())
3801     for (auto &TT : FS->type_tests())
3802       ReferencedTypeIds.insert(TT);
3803 
3804   auto GetReferencedTypesFromVFuncIdVec =
3805       [&](ArrayRef<FunctionSummary::VFuncId> VFs) {
3806         for (auto &VF : VFs)
3807           ReferencedTypeIds.insert(VF.GUID);
3808       };
3809 
3810   GetReferencedTypesFromVFuncIdVec(FS->type_test_assume_vcalls());
3811   GetReferencedTypesFromVFuncIdVec(FS->type_checked_load_vcalls());
3812 
3813   auto GetReferencedTypesFromConstVCallVec =
3814       [&](ArrayRef<FunctionSummary::ConstVCall> VCs) {
3815         for (auto &VC : VCs)
3816           ReferencedTypeIds.insert(VC.VFunc.GUID);
3817       };
3818 
3819   GetReferencedTypesFromConstVCallVec(FS->type_test_assume_const_vcalls());
3820   GetReferencedTypesFromConstVCallVec(FS->type_checked_load_const_vcalls());
3821 }
3822 
3823 static void writeWholeProgramDevirtResolutionByArg(
3824     SmallVector<uint64_t, 64> &NameVals, const std::vector<uint64_t> &args,
3825     const WholeProgramDevirtResolution::ByArg &ByArg) {
3826   NameVals.push_back(args.size());
3827   llvm::append_range(NameVals, args);
3828 
3829   NameVals.push_back(ByArg.TheKind);
3830   NameVals.push_back(ByArg.Info);
3831   NameVals.push_back(ByArg.Byte);
3832   NameVals.push_back(ByArg.Bit);
3833 }
3834 
3835 static void writeWholeProgramDevirtResolution(
3836     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3837     uint64_t Id, const WholeProgramDevirtResolution &Wpd) {
3838   NameVals.push_back(Id);
3839 
3840   NameVals.push_back(Wpd.TheKind);
3841   NameVals.push_back(StrtabBuilder.add(Wpd.SingleImplName));
3842   NameVals.push_back(Wpd.SingleImplName.size());
3843 
3844   NameVals.push_back(Wpd.ResByArg.size());
3845   for (auto &A : Wpd.ResByArg)
3846     writeWholeProgramDevirtResolutionByArg(NameVals, A.first, A.second);
3847 }
3848 
3849 static void writeTypeIdSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
3850                                      StringTableBuilder &StrtabBuilder,
3851                                      const std::string &Id,
3852                                      const TypeIdSummary &Summary) {
3853   NameVals.push_back(StrtabBuilder.add(Id));
3854   NameVals.push_back(Id.size());
3855 
3856   NameVals.push_back(Summary.TTRes.TheKind);
3857   NameVals.push_back(Summary.TTRes.SizeM1BitWidth);
3858   NameVals.push_back(Summary.TTRes.AlignLog2);
3859   NameVals.push_back(Summary.TTRes.SizeM1);
3860   NameVals.push_back(Summary.TTRes.BitMask);
3861   NameVals.push_back(Summary.TTRes.InlineBits);
3862 
3863   for (auto &W : Summary.WPDRes)
3864     writeWholeProgramDevirtResolution(NameVals, StrtabBuilder, W.first,
3865                                       W.second);
3866 }
3867 
3868 static void writeTypeIdCompatibleVtableSummaryRecord(
3869     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3870     const std::string &Id, const TypeIdCompatibleVtableInfo &Summary,
3871     ValueEnumerator &VE) {
3872   NameVals.push_back(StrtabBuilder.add(Id));
3873   NameVals.push_back(Id.size());
3874 
3875   for (auto &P : Summary) {
3876     NameVals.push_back(P.AddressPointOffset);
3877     NameVals.push_back(VE.getValueID(P.VTableVI.getValue()));
3878   }
3879 }
3880 
3881 // Helper to emit a single function summary record.
3882 void ModuleBitcodeWriterBase::writePerModuleFunctionSummaryRecord(
3883     SmallVector<uint64_t, 64> &NameVals, GlobalValueSummary *Summary,
3884     unsigned ValueID, unsigned FSCallsAbbrev, unsigned FSCallsProfileAbbrev,
3885     const Function &F) {
3886   NameVals.push_back(ValueID);
3887 
3888   FunctionSummary *FS = cast<FunctionSummary>(Summary);
3889 
3890   writeFunctionTypeMetadataRecords(
3891       Stream, FS, [&](const ValueInfo &VI) -> Optional<unsigned> {
3892         return {VE.getValueID(VI.getValue())};
3893       });
3894 
3895   auto SpecialRefCnts = FS->specialRefCounts();
3896   NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
3897   NameVals.push_back(FS->instCount());
3898   NameVals.push_back(getEncodedFFlags(FS->fflags()));
3899   NameVals.push_back(FS->refs().size());
3900   NameVals.push_back(SpecialRefCnts.first);  // rorefcnt
3901   NameVals.push_back(SpecialRefCnts.second); // worefcnt
3902 
3903   for (auto &RI : FS->refs())
3904     NameVals.push_back(VE.getValueID(RI.getValue()));
3905 
3906   bool HasProfileData =
3907       F.hasProfileData() || ForceSummaryEdgesCold != FunctionSummary::FSHT_None;
3908   for (auto &ECI : FS->calls()) {
3909     NameVals.push_back(getValueId(ECI.first));
3910     if (HasProfileData)
3911       NameVals.push_back(static_cast<uint8_t>(ECI.second.Hotness));
3912     else if (WriteRelBFToSummary)
3913       NameVals.push_back(ECI.second.RelBlockFreq);
3914   }
3915 
3916   unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
3917   unsigned Code =
3918       (HasProfileData ? bitc::FS_PERMODULE_PROFILE
3919                       : (WriteRelBFToSummary ? bitc::FS_PERMODULE_RELBF
3920                                              : bitc::FS_PERMODULE));
3921 
3922   // Emit the finished record.
3923   Stream.EmitRecord(Code, NameVals, FSAbbrev);
3924   NameVals.clear();
3925 }
3926 
3927 // Collect the global value references in the given variable's initializer,
3928 // and emit them in a summary record.
3929 void ModuleBitcodeWriterBase::writeModuleLevelReferences(
3930     const GlobalVariable &V, SmallVector<uint64_t, 64> &NameVals,
3931     unsigned FSModRefsAbbrev, unsigned FSModVTableRefsAbbrev) {
3932   auto VI = Index->getValueInfo(V.getGUID());
3933   if (!VI || VI.getSummaryList().empty()) {
3934     // Only declarations should not have a summary (a declaration might however
3935     // have a summary if the def was in module level asm).
3936     assert(V.isDeclaration());
3937     return;
3938   }
3939   auto *Summary = VI.getSummaryList()[0].get();
3940   NameVals.push_back(VE.getValueID(&V));
3941   GlobalVarSummary *VS = cast<GlobalVarSummary>(Summary);
3942   NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
3943   NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
3944 
3945   auto VTableFuncs = VS->vTableFuncs();
3946   if (!VTableFuncs.empty())
3947     NameVals.push_back(VS->refs().size());
3948 
3949   unsigned SizeBeforeRefs = NameVals.size();
3950   for (auto &RI : VS->refs())
3951     NameVals.push_back(VE.getValueID(RI.getValue()));
3952   // Sort the refs for determinism output, the vector returned by FS->refs() has
3953   // been initialized from a DenseSet.
3954   llvm::sort(drop_begin(NameVals, SizeBeforeRefs));
3955 
3956   if (VTableFuncs.empty())
3957     Stream.EmitRecord(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS, NameVals,
3958                       FSModRefsAbbrev);
3959   else {
3960     // VTableFuncs pairs should already be sorted by offset.
3961     for (auto &P : VTableFuncs) {
3962       NameVals.push_back(VE.getValueID(P.FuncVI.getValue()));
3963       NameVals.push_back(P.VTableOffset);
3964     }
3965 
3966     Stream.EmitRecord(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS, NameVals,
3967                       FSModVTableRefsAbbrev);
3968   }
3969   NameVals.clear();
3970 }
3971 
3972 /// Emit the per-module summary section alongside the rest of
3973 /// the module's bitcode.
3974 void ModuleBitcodeWriterBase::writePerModuleGlobalValueSummary() {
3975   // By default we compile with ThinLTO if the module has a summary, but the
3976   // client can request full LTO with a module flag.
3977   bool IsThinLTO = true;
3978   if (auto *MD =
3979           mdconst::extract_or_null<ConstantInt>(M.getModuleFlag("ThinLTO")))
3980     IsThinLTO = MD->getZExtValue();
3981   Stream.EnterSubblock(IsThinLTO ? bitc::GLOBALVAL_SUMMARY_BLOCK_ID
3982                                  : bitc::FULL_LTO_GLOBALVAL_SUMMARY_BLOCK_ID,
3983                        4);
3984 
3985   Stream.EmitRecord(
3986       bitc::FS_VERSION,
3987       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
3988 
3989   // Write the index flags.
3990   uint64_t Flags = 0;
3991   // Bits 1-3 are set only in the combined index, skip them.
3992   if (Index->enableSplitLTOUnit())
3993     Flags |= 0x8;
3994   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Flags});
3995 
3996   if (Index->begin() == Index->end()) {
3997     Stream.ExitBlock();
3998     return;
3999   }
4000 
4001   for (const auto &GVI : valueIds()) {
4002     Stream.EmitRecord(bitc::FS_VALUE_GUID,
4003                       ArrayRef<uint64_t>{GVI.second, GVI.first});
4004   }
4005 
4006   // Abbrev for FS_PERMODULE_PROFILE.
4007   auto Abbv = std::make_shared<BitCodeAbbrev>();
4008   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_PROFILE));
4009   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4010   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4011   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4012   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4013   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4014   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4015   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4016   // numrefs x valueid, n x (valueid, hotness)
4017   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4018   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4019   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4020 
4021   // Abbrev for FS_PERMODULE or FS_PERMODULE_RELBF.
4022   Abbv = std::make_shared<BitCodeAbbrev>();
4023   if (WriteRelBFToSummary)
4024     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_RELBF));
4025   else
4026     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE));
4027   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4028   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4029   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4030   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4031   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4032   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4033   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4034   // numrefs x valueid, n x (valueid [, rel_block_freq])
4035   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4036   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4037   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4038 
4039   // Abbrev for FS_PERMODULE_GLOBALVAR_INIT_REFS.
4040   Abbv = std::make_shared<BitCodeAbbrev>();
4041   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS));
4042   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
4043   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
4044   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));  // valueids
4045   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4046   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4047 
4048   // Abbrev for FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS.
4049   Abbv = std::make_shared<BitCodeAbbrev>();
4050   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS));
4051   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
4052   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
4053   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numrefs
4054   // numrefs x valueid, n x (valueid , offset)
4055   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4056   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4057   unsigned FSModVTableRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4058 
4059   // Abbrev for FS_ALIAS.
4060   Abbv = std::make_shared<BitCodeAbbrev>();
4061   Abbv->Add(BitCodeAbbrevOp(bitc::FS_ALIAS));
4062   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4063   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4064   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4065   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4066 
4067   // Abbrev for FS_TYPE_ID_METADATA
4068   Abbv = std::make_shared<BitCodeAbbrev>();
4069   Abbv->Add(BitCodeAbbrevOp(bitc::FS_TYPE_ID_METADATA));
4070   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid strtab index
4071   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid length
4072   // n x (valueid , offset)
4073   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4074   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4075   unsigned TypeIdCompatibleVtableAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4076 
4077   SmallVector<uint64_t, 64> NameVals;
4078   // Iterate over the list of functions instead of the Index to
4079   // ensure the ordering is stable.
4080   for (const Function &F : M) {
4081     // Summary emission does not support anonymous functions, they have to
4082     // renamed using the anonymous function renaming pass.
4083     if (!F.hasName())
4084       report_fatal_error("Unexpected anonymous function when writing summary");
4085 
4086     ValueInfo VI = Index->getValueInfo(F.getGUID());
4087     if (!VI || VI.getSummaryList().empty()) {
4088       // Only declarations should not have a summary (a declaration might
4089       // however have a summary if the def was in module level asm).
4090       assert(F.isDeclaration());
4091       continue;
4092     }
4093     auto *Summary = VI.getSummaryList()[0].get();
4094     writePerModuleFunctionSummaryRecord(NameVals, Summary, VE.getValueID(&F),
4095                                         FSCallsAbbrev, FSCallsProfileAbbrev, F);
4096   }
4097 
4098   // Capture references from GlobalVariable initializers, which are outside
4099   // of a function scope.
4100   for (const GlobalVariable &G : M.globals())
4101     writeModuleLevelReferences(G, NameVals, FSModRefsAbbrev,
4102                                FSModVTableRefsAbbrev);
4103 
4104   for (const GlobalAlias &A : M.aliases()) {
4105     auto *Aliasee = A.getAliaseeObject();
4106     if (!Aliasee->hasName())
4107       // Nameless function don't have an entry in the summary, skip it.
4108       continue;
4109     auto AliasId = VE.getValueID(&A);
4110     auto AliaseeId = VE.getValueID(Aliasee);
4111     NameVals.push_back(AliasId);
4112     auto *Summary = Index->getGlobalValueSummary(A);
4113     AliasSummary *AS = cast<AliasSummary>(Summary);
4114     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
4115     NameVals.push_back(AliaseeId);
4116     Stream.EmitRecord(bitc::FS_ALIAS, NameVals, FSAliasAbbrev);
4117     NameVals.clear();
4118   }
4119 
4120   for (auto &S : Index->typeIdCompatibleVtableMap()) {
4121     writeTypeIdCompatibleVtableSummaryRecord(NameVals, StrtabBuilder, S.first,
4122                                              S.second, VE);
4123     Stream.EmitRecord(bitc::FS_TYPE_ID_METADATA, NameVals,
4124                       TypeIdCompatibleVtableAbbrev);
4125     NameVals.clear();
4126   }
4127 
4128   Stream.EmitRecord(bitc::FS_BLOCK_COUNT,
4129                     ArrayRef<uint64_t>{Index->getBlockCount()});
4130 
4131   Stream.ExitBlock();
4132 }
4133 
4134 /// Emit the combined summary section into the combined index file.
4135 void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
4136   Stream.EnterSubblock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID, 3);
4137   Stream.EmitRecord(
4138       bitc::FS_VERSION,
4139       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
4140 
4141   // Write the index flags.
4142   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Index.getFlags()});
4143 
4144   for (const auto &GVI : valueIds()) {
4145     Stream.EmitRecord(bitc::FS_VALUE_GUID,
4146                       ArrayRef<uint64_t>{GVI.second, GVI.first});
4147   }
4148 
4149   // Abbrev for FS_COMBINED.
4150   auto Abbv = std::make_shared<BitCodeAbbrev>();
4151   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED));
4152   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4153   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4154   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4155   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4156   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4157   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
4158   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4159   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4160   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4161   // numrefs x valueid, n x (valueid)
4162   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4163   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4164   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4165 
4166   // Abbrev for FS_COMBINED_PROFILE.
4167   Abbv = std::make_shared<BitCodeAbbrev>();
4168   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_PROFILE));
4169   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4170   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4171   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4172   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4173   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4174   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
4175   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4176   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4177   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4178   // numrefs x valueid, n x (valueid, hotness)
4179   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4180   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4181   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4182 
4183   // Abbrev for FS_COMBINED_GLOBALVAR_INIT_REFS.
4184   Abbv = std::make_shared<BitCodeAbbrev>();
4185   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS));
4186   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4187   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4188   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4189   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));    // valueids
4190   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4191   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4192 
4193   // Abbrev for FS_COMBINED_ALIAS.
4194   Abbv = std::make_shared<BitCodeAbbrev>();
4195   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_ALIAS));
4196   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4197   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4198   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4199   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4200   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4201 
4202   // The aliases are emitted as a post-pass, and will point to the value
4203   // id of the aliasee. Save them in a vector for post-processing.
4204   SmallVector<AliasSummary *, 64> Aliases;
4205 
4206   // Save the value id for each summary for alias emission.
4207   DenseMap<const GlobalValueSummary *, unsigned> SummaryToValueIdMap;
4208 
4209   SmallVector<uint64_t, 64> NameVals;
4210 
4211   // Set that will be populated during call to writeFunctionTypeMetadataRecords
4212   // with the type ids referenced by this index file.
4213   std::set<GlobalValue::GUID> ReferencedTypeIds;
4214 
4215   // For local linkage, we also emit the original name separately
4216   // immediately after the record.
4217   auto MaybeEmitOriginalName = [&](GlobalValueSummary &S) {
4218     // We don't need to emit the original name if we are writing the index for
4219     // distributed backends (in which case ModuleToSummariesForIndex is
4220     // non-null). The original name is only needed during the thin link, since
4221     // for SamplePGO the indirect call targets for local functions have
4222     // have the original name annotated in profile.
4223     // Continue to emit it when writing out the entire combined index, which is
4224     // used in testing the thin link via llvm-lto.
4225     if (ModuleToSummariesForIndex || !GlobalValue::isLocalLinkage(S.linkage()))
4226       return;
4227     NameVals.push_back(S.getOriginalName());
4228     Stream.EmitRecord(bitc::FS_COMBINED_ORIGINAL_NAME, NameVals);
4229     NameVals.clear();
4230   };
4231 
4232   std::set<GlobalValue::GUID> DefOrUseGUIDs;
4233   forEachSummary([&](GVInfo I, bool IsAliasee) {
4234     GlobalValueSummary *S = I.second;
4235     assert(S);
4236     DefOrUseGUIDs.insert(I.first);
4237     for (const ValueInfo &VI : S->refs())
4238       DefOrUseGUIDs.insert(VI.getGUID());
4239 
4240     auto ValueId = getValueId(I.first);
4241     assert(ValueId);
4242     SummaryToValueIdMap[S] = *ValueId;
4243 
4244     // If this is invoked for an aliasee, we want to record the above
4245     // mapping, but then not emit a summary entry (if the aliasee is
4246     // to be imported, we will invoke this separately with IsAliasee=false).
4247     if (IsAliasee)
4248       return;
4249 
4250     if (auto *AS = dyn_cast<AliasSummary>(S)) {
4251       // Will process aliases as a post-pass because the reader wants all
4252       // global to be loaded first.
4253       Aliases.push_back(AS);
4254       return;
4255     }
4256 
4257     if (auto *VS = dyn_cast<GlobalVarSummary>(S)) {
4258       NameVals.push_back(*ValueId);
4259       NameVals.push_back(Index.getModuleId(VS->modulePath()));
4260       NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
4261       NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
4262       for (auto &RI : VS->refs()) {
4263         auto RefValueId = getValueId(RI.getGUID());
4264         if (!RefValueId)
4265           continue;
4266         NameVals.push_back(*RefValueId);
4267       }
4268 
4269       // Emit the finished record.
4270       Stream.EmitRecord(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS, NameVals,
4271                         FSModRefsAbbrev);
4272       NameVals.clear();
4273       MaybeEmitOriginalName(*S);
4274       return;
4275     }
4276 
4277     auto GetValueId = [&](const ValueInfo &VI) -> Optional<unsigned> {
4278       return getValueId(VI.getGUID());
4279     };
4280 
4281     auto *FS = cast<FunctionSummary>(S);
4282     writeFunctionTypeMetadataRecords(Stream, FS, GetValueId);
4283     getReferencedTypeIds(FS, ReferencedTypeIds);
4284 
4285     NameVals.push_back(*ValueId);
4286     NameVals.push_back(Index.getModuleId(FS->modulePath()));
4287     NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
4288     NameVals.push_back(FS->instCount());
4289     NameVals.push_back(getEncodedFFlags(FS->fflags()));
4290     NameVals.push_back(FS->entryCount());
4291 
4292     // Fill in below
4293     NameVals.push_back(0); // numrefs
4294     NameVals.push_back(0); // rorefcnt
4295     NameVals.push_back(0); // worefcnt
4296 
4297     unsigned Count = 0, RORefCnt = 0, WORefCnt = 0;
4298     for (auto &RI : FS->refs()) {
4299       auto RefValueId = getValueId(RI.getGUID());
4300       if (!RefValueId)
4301         continue;
4302       NameVals.push_back(*RefValueId);
4303       if (RI.isReadOnly())
4304         RORefCnt++;
4305       else if (RI.isWriteOnly())
4306         WORefCnt++;
4307       Count++;
4308     }
4309     NameVals[6] = Count;
4310     NameVals[7] = RORefCnt;
4311     NameVals[8] = WORefCnt;
4312 
4313     bool HasProfileData = false;
4314     for (auto &EI : FS->calls()) {
4315       HasProfileData |=
4316           EI.second.getHotness() != CalleeInfo::HotnessType::Unknown;
4317       if (HasProfileData)
4318         break;
4319     }
4320 
4321     for (auto &EI : FS->calls()) {
4322       // If this GUID doesn't have a value id, it doesn't have a function
4323       // summary and we don't need to record any calls to it.
4324       Optional<unsigned> CallValueId = GetValueId(EI.first);
4325       if (!CallValueId)
4326         continue;
4327       NameVals.push_back(*CallValueId);
4328       if (HasProfileData)
4329         NameVals.push_back(static_cast<uint8_t>(EI.second.Hotness));
4330     }
4331 
4332     unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
4333     unsigned Code =
4334         (HasProfileData ? bitc::FS_COMBINED_PROFILE : bitc::FS_COMBINED);
4335 
4336     // Emit the finished record.
4337     Stream.EmitRecord(Code, NameVals, FSAbbrev);
4338     NameVals.clear();
4339     MaybeEmitOriginalName(*S);
4340   });
4341 
4342   for (auto *AS : Aliases) {
4343     auto AliasValueId = SummaryToValueIdMap[AS];
4344     assert(AliasValueId);
4345     NameVals.push_back(AliasValueId);
4346     NameVals.push_back(Index.getModuleId(AS->modulePath()));
4347     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
4348     auto AliaseeValueId = SummaryToValueIdMap[&AS->getAliasee()];
4349     assert(AliaseeValueId);
4350     NameVals.push_back(AliaseeValueId);
4351 
4352     // Emit the finished record.
4353     Stream.EmitRecord(bitc::FS_COMBINED_ALIAS, NameVals, FSAliasAbbrev);
4354     NameVals.clear();
4355     MaybeEmitOriginalName(*AS);
4356 
4357     if (auto *FS = dyn_cast<FunctionSummary>(&AS->getAliasee()))
4358       getReferencedTypeIds(FS, ReferencedTypeIds);
4359   }
4360 
4361   if (!Index.cfiFunctionDefs().empty()) {
4362     for (auto &S : Index.cfiFunctionDefs()) {
4363       if (DefOrUseGUIDs.count(
4364               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4365         NameVals.push_back(StrtabBuilder.add(S));
4366         NameVals.push_back(S.size());
4367       }
4368     }
4369     if (!NameVals.empty()) {
4370       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DEFS, NameVals);
4371       NameVals.clear();
4372     }
4373   }
4374 
4375   if (!Index.cfiFunctionDecls().empty()) {
4376     for (auto &S : Index.cfiFunctionDecls()) {
4377       if (DefOrUseGUIDs.count(
4378               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4379         NameVals.push_back(StrtabBuilder.add(S));
4380         NameVals.push_back(S.size());
4381       }
4382     }
4383     if (!NameVals.empty()) {
4384       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DECLS, NameVals);
4385       NameVals.clear();
4386     }
4387   }
4388 
4389   // Walk the GUIDs that were referenced, and write the
4390   // corresponding type id records.
4391   for (auto &T : ReferencedTypeIds) {
4392     auto TidIter = Index.typeIds().equal_range(T);
4393     for (auto It = TidIter.first; It != TidIter.second; ++It) {
4394       writeTypeIdSummaryRecord(NameVals, StrtabBuilder, It->second.first,
4395                                It->second.second);
4396       Stream.EmitRecord(bitc::FS_TYPE_ID, NameVals);
4397       NameVals.clear();
4398     }
4399   }
4400 
4401   Stream.EmitRecord(bitc::FS_BLOCK_COUNT,
4402                     ArrayRef<uint64_t>{Index.getBlockCount()});
4403 
4404   Stream.ExitBlock();
4405 }
4406 
4407 /// Create the "IDENTIFICATION_BLOCK_ID" containing a single string with the
4408 /// current llvm version, and a record for the epoch number.
4409 static void writeIdentificationBlock(BitstreamWriter &Stream) {
4410   Stream.EnterSubblock(bitc::IDENTIFICATION_BLOCK_ID, 5);
4411 
4412   // Write the "user readable" string identifying the bitcode producer
4413   auto Abbv = std::make_shared<BitCodeAbbrev>();
4414   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_STRING));
4415   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4416   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
4417   auto StringAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4418   writeStringRecord(Stream, bitc::IDENTIFICATION_CODE_STRING,
4419                     "LLVM" LLVM_VERSION_STRING, StringAbbrev);
4420 
4421   // Write the epoch version
4422   Abbv = std::make_shared<BitCodeAbbrev>();
4423   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_EPOCH));
4424   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
4425   auto EpochAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4426   constexpr std::array<unsigned, 1> Vals = {{bitc::BITCODE_CURRENT_EPOCH}};
4427   Stream.EmitRecord(bitc::IDENTIFICATION_CODE_EPOCH, Vals, EpochAbbrev);
4428   Stream.ExitBlock();
4429 }
4430 
4431 void ModuleBitcodeWriter::writeModuleHash(size_t BlockStartPos) {
4432   // Emit the module's hash.
4433   // MODULE_CODE_HASH: [5*i32]
4434   if (GenerateHash) {
4435     uint32_t Vals[5];
4436     Hasher.update(ArrayRef<uint8_t>((const uint8_t *)&(Buffer)[BlockStartPos],
4437                                     Buffer.size() - BlockStartPos));
4438     std::array<uint8_t, 20> Hash = Hasher.result();
4439     for (int Pos = 0; Pos < 20; Pos += 4) {
4440       Vals[Pos / 4] = support::endian::read32be(Hash.data() + Pos);
4441     }
4442 
4443     // Emit the finished record.
4444     Stream.EmitRecord(bitc::MODULE_CODE_HASH, Vals);
4445 
4446     if (ModHash)
4447       // Save the written hash value.
4448       llvm::copy(Vals, std::begin(*ModHash));
4449   }
4450 }
4451 
4452 void ModuleBitcodeWriter::write() {
4453   writeIdentificationBlock(Stream);
4454 
4455   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4456   size_t BlockStartPos = Buffer.size();
4457 
4458   writeModuleVersion();
4459 
4460   // Emit blockinfo, which defines the standard abbreviations etc.
4461   writeBlockInfo();
4462 
4463   // Emit information describing all of the types in the module.
4464   writeTypeTable();
4465 
4466   // Emit information about attribute groups.
4467   writeAttributeGroupTable();
4468 
4469   // Emit information about parameter attributes.
4470   writeAttributeTable();
4471 
4472   writeComdats();
4473 
4474   // Emit top-level description of module, including target triple, inline asm,
4475   // descriptors for global variables, and function prototype info.
4476   writeModuleInfo();
4477 
4478   // Emit constants.
4479   writeModuleConstants();
4480 
4481   // Emit metadata kind names.
4482   writeModuleMetadataKinds();
4483 
4484   // Emit metadata.
4485   writeModuleMetadata();
4486 
4487   // Emit module-level use-lists.
4488   if (VE.shouldPreserveUseListOrder())
4489     writeUseListBlock(nullptr);
4490 
4491   writeOperandBundleTags();
4492   writeSyncScopeNames();
4493 
4494   // Emit function bodies.
4495   DenseMap<const Function *, uint64_t> FunctionToBitcodeIndex;
4496   for (const Function &F : M)
4497     if (!F.isDeclaration())
4498       writeFunction(F, FunctionToBitcodeIndex);
4499 
4500   // Need to write after the above call to WriteFunction which populates
4501   // the summary information in the index.
4502   if (Index)
4503     writePerModuleGlobalValueSummary();
4504 
4505   writeGlobalValueSymbolTable(FunctionToBitcodeIndex);
4506 
4507   writeModuleHash(BlockStartPos);
4508 
4509   Stream.ExitBlock();
4510 }
4511 
4512 static void writeInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
4513                                uint32_t &Position) {
4514   support::endian::write32le(&Buffer[Position], Value);
4515   Position += 4;
4516 }
4517 
4518 /// If generating a bc file on darwin, we have to emit a
4519 /// header and trailer to make it compatible with the system archiver.  To do
4520 /// this we emit the following header, and then emit a trailer that pads the
4521 /// file out to be a multiple of 16 bytes.
4522 ///
4523 /// struct bc_header {
4524 ///   uint32_t Magic;         // 0x0B17C0DE
4525 ///   uint32_t Version;       // Version, currently always 0.
4526 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
4527 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
4528 ///   uint32_t CPUType;       // CPU specifier.
4529 ///   ... potentially more later ...
4530 /// };
4531 static void emitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
4532                                          const Triple &TT) {
4533   unsigned CPUType = ~0U;
4534 
4535   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
4536   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
4537   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
4538   // specific constants here because they are implicitly part of the Darwin ABI.
4539   enum {
4540     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
4541     DARWIN_CPU_TYPE_X86        = 7,
4542     DARWIN_CPU_TYPE_ARM        = 12,
4543     DARWIN_CPU_TYPE_POWERPC    = 18
4544   };
4545 
4546   Triple::ArchType Arch = TT.getArch();
4547   if (Arch == Triple::x86_64)
4548     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
4549   else if (Arch == Triple::x86)
4550     CPUType = DARWIN_CPU_TYPE_X86;
4551   else if (Arch == Triple::ppc)
4552     CPUType = DARWIN_CPU_TYPE_POWERPC;
4553   else if (Arch == Triple::ppc64)
4554     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
4555   else if (Arch == Triple::arm || Arch == Triple::thumb)
4556     CPUType = DARWIN_CPU_TYPE_ARM;
4557 
4558   // Traditional Bitcode starts after header.
4559   assert(Buffer.size() >= BWH_HeaderSize &&
4560          "Expected header size to be reserved");
4561   unsigned BCOffset = BWH_HeaderSize;
4562   unsigned BCSize = Buffer.size() - BWH_HeaderSize;
4563 
4564   // Write the magic and version.
4565   unsigned Position = 0;
4566   writeInt32ToBuffer(0x0B17C0DE, Buffer, Position);
4567   writeInt32ToBuffer(0, Buffer, Position); // Version.
4568   writeInt32ToBuffer(BCOffset, Buffer, Position);
4569   writeInt32ToBuffer(BCSize, Buffer, Position);
4570   writeInt32ToBuffer(CPUType, Buffer, Position);
4571 
4572   // If the file is not a multiple of 16 bytes, insert dummy padding.
4573   while (Buffer.size() & 15)
4574     Buffer.push_back(0);
4575 }
4576 
4577 /// Helper to write the header common to all bitcode files.
4578 static void writeBitcodeHeader(BitstreamWriter &Stream) {
4579   // Emit the file header.
4580   Stream.Emit((unsigned)'B', 8);
4581   Stream.Emit((unsigned)'C', 8);
4582   Stream.Emit(0x0, 4);
4583   Stream.Emit(0xC, 4);
4584   Stream.Emit(0xE, 4);
4585   Stream.Emit(0xD, 4);
4586 }
4587 
4588 BitcodeWriter::BitcodeWriter(SmallVectorImpl<char> &Buffer, raw_fd_stream *FS)
4589     : Buffer(Buffer), Stream(new BitstreamWriter(Buffer, FS, FlushThreshold)) {
4590   writeBitcodeHeader(*Stream);
4591 }
4592 
4593 BitcodeWriter::~BitcodeWriter() { assert(WroteStrtab); }
4594 
4595 void BitcodeWriter::writeBlob(unsigned Block, unsigned Record, StringRef Blob) {
4596   Stream->EnterSubblock(Block, 3);
4597 
4598   auto Abbv = std::make_shared<BitCodeAbbrev>();
4599   Abbv->Add(BitCodeAbbrevOp(Record));
4600   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
4601   auto AbbrevNo = Stream->EmitAbbrev(std::move(Abbv));
4602 
4603   Stream->EmitRecordWithBlob(AbbrevNo, ArrayRef<uint64_t>{Record}, Blob);
4604 
4605   Stream->ExitBlock();
4606 }
4607 
4608 void BitcodeWriter::writeSymtab() {
4609   assert(!WroteStrtab && !WroteSymtab);
4610 
4611   // If any module has module-level inline asm, we will require a registered asm
4612   // parser for the target so that we can create an accurate symbol table for
4613   // the module.
4614   for (Module *M : Mods) {
4615     if (M->getModuleInlineAsm().empty())
4616       continue;
4617 
4618     std::string Err;
4619     const Triple TT(M->getTargetTriple());
4620     const Target *T = TargetRegistry::lookupTarget(TT.str(), Err);
4621     if (!T || !T->hasMCAsmParser())
4622       return;
4623   }
4624 
4625   WroteSymtab = true;
4626   SmallVector<char, 0> Symtab;
4627   // The irsymtab::build function may be unable to create a symbol table if the
4628   // module is malformed (e.g. it contains an invalid alias). Writing a symbol
4629   // table is not required for correctness, but we still want to be able to
4630   // write malformed modules to bitcode files, so swallow the error.
4631   if (Error E = irsymtab::build(Mods, Symtab, StrtabBuilder, Alloc)) {
4632     consumeError(std::move(E));
4633     return;
4634   }
4635 
4636   writeBlob(bitc::SYMTAB_BLOCK_ID, bitc::SYMTAB_BLOB,
4637             {Symtab.data(), Symtab.size()});
4638 }
4639 
4640 void BitcodeWriter::writeStrtab() {
4641   assert(!WroteStrtab);
4642 
4643   std::vector<char> Strtab;
4644   StrtabBuilder.finalizeInOrder();
4645   Strtab.resize(StrtabBuilder.getSize());
4646   StrtabBuilder.write((uint8_t *)Strtab.data());
4647 
4648   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB,
4649             {Strtab.data(), Strtab.size()});
4650 
4651   WroteStrtab = true;
4652 }
4653 
4654 void BitcodeWriter::copyStrtab(StringRef Strtab) {
4655   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB, Strtab);
4656   WroteStrtab = true;
4657 }
4658 
4659 void BitcodeWriter::writeModule(const Module &M,
4660                                 bool ShouldPreserveUseListOrder,
4661                                 const ModuleSummaryIndex *Index,
4662                                 bool GenerateHash, ModuleHash *ModHash) {
4663   assert(!WroteStrtab);
4664 
4665   // The Mods vector is used by irsymtab::build, which requires non-const
4666   // Modules in case it needs to materialize metadata. But the bitcode writer
4667   // requires that the module is materialized, so we can cast to non-const here,
4668   // after checking that it is in fact materialized.
4669   assert(M.isMaterialized());
4670   Mods.push_back(const_cast<Module *>(&M));
4671 
4672   ModuleBitcodeWriter ModuleWriter(M, Buffer, StrtabBuilder, *Stream,
4673                                    ShouldPreserveUseListOrder, Index,
4674                                    GenerateHash, ModHash);
4675   ModuleWriter.write();
4676 }
4677 
4678 void BitcodeWriter::writeIndex(
4679     const ModuleSummaryIndex *Index,
4680     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4681   IndexBitcodeWriter IndexWriter(*Stream, StrtabBuilder, *Index,
4682                                  ModuleToSummariesForIndex);
4683   IndexWriter.write();
4684 }
4685 
4686 /// Write the specified module to the specified output stream.
4687 void llvm::WriteBitcodeToFile(const Module &M, raw_ostream &Out,
4688                               bool ShouldPreserveUseListOrder,
4689                               const ModuleSummaryIndex *Index,
4690                               bool GenerateHash, ModuleHash *ModHash) {
4691   SmallVector<char, 0> Buffer;
4692   Buffer.reserve(256*1024);
4693 
4694   // If this is darwin or another generic macho target, reserve space for the
4695   // header.
4696   Triple TT(M.getTargetTriple());
4697   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4698     Buffer.insert(Buffer.begin(), BWH_HeaderSize, 0);
4699 
4700   BitcodeWriter Writer(Buffer, dyn_cast<raw_fd_stream>(&Out));
4701   Writer.writeModule(M, ShouldPreserveUseListOrder, Index, GenerateHash,
4702                      ModHash);
4703   Writer.writeSymtab();
4704   Writer.writeStrtab();
4705 
4706   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4707     emitDarwinBCHeaderAndTrailer(Buffer, TT);
4708 
4709   // Write the generated bitstream to "Out".
4710   if (!Buffer.empty())
4711     Out.write((char *)&Buffer.front(), Buffer.size());
4712 }
4713 
4714 void IndexBitcodeWriter::write() {
4715   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4716 
4717   writeModuleVersion();
4718 
4719   // Write the module paths in the combined index.
4720   writeModStrings();
4721 
4722   // Write the summary combined index records.
4723   writeCombinedGlobalValueSummary();
4724 
4725   Stream.ExitBlock();
4726 }
4727 
4728 // Write the specified module summary index to the given raw output stream,
4729 // where it will be written in a new bitcode block. This is used when
4730 // writing the combined index file for ThinLTO. When writing a subset of the
4731 // index for a distributed backend, provide a \p ModuleToSummariesForIndex map.
4732 void llvm::writeIndexToFile(
4733     const ModuleSummaryIndex &Index, raw_ostream &Out,
4734     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4735   SmallVector<char, 0> Buffer;
4736   Buffer.reserve(256 * 1024);
4737 
4738   BitcodeWriter Writer(Buffer);
4739   Writer.writeIndex(&Index, ModuleToSummariesForIndex);
4740   Writer.writeStrtab();
4741 
4742   Out.write((char *)&Buffer.front(), Buffer.size());
4743 }
4744 
4745 namespace {
4746 
4747 /// Class to manage the bitcode writing for a thin link bitcode file.
4748 class ThinLinkBitcodeWriter : public ModuleBitcodeWriterBase {
4749   /// ModHash is for use in ThinLTO incremental build, generated while writing
4750   /// the module bitcode file.
4751   const ModuleHash *ModHash;
4752 
4753 public:
4754   ThinLinkBitcodeWriter(const Module &M, StringTableBuilder &StrtabBuilder,
4755                         BitstreamWriter &Stream,
4756                         const ModuleSummaryIndex &Index,
4757                         const ModuleHash &ModHash)
4758       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
4759                                 /*ShouldPreserveUseListOrder=*/false, &Index),
4760         ModHash(&ModHash) {}
4761 
4762   void write();
4763 
4764 private:
4765   void writeSimplifiedModuleInfo();
4766 };
4767 
4768 } // end anonymous namespace
4769 
4770 // This function writes a simpilified module info for thin link bitcode file.
4771 // It only contains the source file name along with the name(the offset and
4772 // size in strtab) and linkage for global values. For the global value info
4773 // entry, in order to keep linkage at offset 5, there are three zeros used
4774 // as padding.
4775 void ThinLinkBitcodeWriter::writeSimplifiedModuleInfo() {
4776   SmallVector<unsigned, 64> Vals;
4777   // Emit the module's source file name.
4778   {
4779     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
4780     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
4781     if (Bits == SE_Char6)
4782       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
4783     else if (Bits == SE_Fixed7)
4784       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
4785 
4786     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
4787     auto Abbv = std::make_shared<BitCodeAbbrev>();
4788     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
4789     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4790     Abbv->Add(AbbrevOpToUse);
4791     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4792 
4793     for (const auto P : M.getSourceFileName())
4794       Vals.push_back((unsigned char)P);
4795 
4796     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
4797     Vals.clear();
4798   }
4799 
4800   // Emit the global variable information.
4801   for (const GlobalVariable &GV : M.globals()) {
4802     // GLOBALVAR: [strtab offset, strtab size, 0, 0, 0, linkage]
4803     Vals.push_back(StrtabBuilder.add(GV.getName()));
4804     Vals.push_back(GV.getName().size());
4805     Vals.push_back(0);
4806     Vals.push_back(0);
4807     Vals.push_back(0);
4808     Vals.push_back(getEncodedLinkage(GV));
4809 
4810     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals);
4811     Vals.clear();
4812   }
4813 
4814   // Emit the function proto information.
4815   for (const Function &F : M) {
4816     // FUNCTION:  [strtab offset, strtab size, 0, 0, 0, linkage]
4817     Vals.push_back(StrtabBuilder.add(F.getName()));
4818     Vals.push_back(F.getName().size());
4819     Vals.push_back(0);
4820     Vals.push_back(0);
4821     Vals.push_back(0);
4822     Vals.push_back(getEncodedLinkage(F));
4823 
4824     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals);
4825     Vals.clear();
4826   }
4827 
4828   // Emit the alias information.
4829   for (const GlobalAlias &A : M.aliases()) {
4830     // ALIAS: [strtab offset, strtab size, 0, 0, 0, linkage]
4831     Vals.push_back(StrtabBuilder.add(A.getName()));
4832     Vals.push_back(A.getName().size());
4833     Vals.push_back(0);
4834     Vals.push_back(0);
4835     Vals.push_back(0);
4836     Vals.push_back(getEncodedLinkage(A));
4837 
4838     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals);
4839     Vals.clear();
4840   }
4841 
4842   // Emit the ifunc information.
4843   for (const GlobalIFunc &I : M.ifuncs()) {
4844     // IFUNC: [strtab offset, strtab size, 0, 0, 0, linkage]
4845     Vals.push_back(StrtabBuilder.add(I.getName()));
4846     Vals.push_back(I.getName().size());
4847     Vals.push_back(0);
4848     Vals.push_back(0);
4849     Vals.push_back(0);
4850     Vals.push_back(getEncodedLinkage(I));
4851 
4852     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
4853     Vals.clear();
4854   }
4855 }
4856 
4857 void ThinLinkBitcodeWriter::write() {
4858   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4859 
4860   writeModuleVersion();
4861 
4862   writeSimplifiedModuleInfo();
4863 
4864   writePerModuleGlobalValueSummary();
4865 
4866   // Write module hash.
4867   Stream.EmitRecord(bitc::MODULE_CODE_HASH, ArrayRef<uint32_t>(*ModHash));
4868 
4869   Stream.ExitBlock();
4870 }
4871 
4872 void BitcodeWriter::writeThinLinkBitcode(const Module &M,
4873                                          const ModuleSummaryIndex &Index,
4874                                          const ModuleHash &ModHash) {
4875   assert(!WroteStrtab);
4876 
4877   // The Mods vector is used by irsymtab::build, which requires non-const
4878   // Modules in case it needs to materialize metadata. But the bitcode writer
4879   // requires that the module is materialized, so we can cast to non-const here,
4880   // after checking that it is in fact materialized.
4881   assert(M.isMaterialized());
4882   Mods.push_back(const_cast<Module *>(&M));
4883 
4884   ThinLinkBitcodeWriter ThinLinkWriter(M, StrtabBuilder, *Stream, Index,
4885                                        ModHash);
4886   ThinLinkWriter.write();
4887 }
4888 
4889 // Write the specified thin link bitcode file to the given raw output stream,
4890 // where it will be written in a new bitcode block. This is used when
4891 // writing the per-module index file for ThinLTO.
4892 void llvm::writeThinLinkBitcodeToFile(const Module &M, raw_ostream &Out,
4893                                       const ModuleSummaryIndex &Index,
4894                                       const ModuleHash &ModHash) {
4895   SmallVector<char, 0> Buffer;
4896   Buffer.reserve(256 * 1024);
4897 
4898   BitcodeWriter Writer(Buffer);
4899   Writer.writeThinLinkBitcode(M, Index, ModHash);
4900   Writer.writeSymtab();
4901   Writer.writeStrtab();
4902 
4903   Out.write((char *)&Buffer.front(), Buffer.size());
4904 }
4905 
4906 static const char *getSectionNameForBitcode(const Triple &T) {
4907   switch (T.getObjectFormat()) {
4908   case Triple::MachO:
4909     return "__LLVM,__bitcode";
4910   case Triple::COFF:
4911   case Triple::ELF:
4912   case Triple::Wasm:
4913   case Triple::UnknownObjectFormat:
4914     return ".llvmbc";
4915   case Triple::GOFF:
4916     llvm_unreachable("GOFF is not yet implemented");
4917     break;
4918   case Triple::SPIRV:
4919     llvm_unreachable("SPIRV is not yet implemented");
4920     break;
4921   case Triple::XCOFF:
4922     llvm_unreachable("XCOFF is not yet implemented");
4923     break;
4924   case Triple::DXContainer:
4925     llvm_unreachable("DXContainer is not yet implemented");
4926     break;
4927   }
4928   llvm_unreachable("Unimplemented ObjectFormatType");
4929 }
4930 
4931 static const char *getSectionNameForCommandline(const Triple &T) {
4932   switch (T.getObjectFormat()) {
4933   case Triple::MachO:
4934     return "__LLVM,__cmdline";
4935   case Triple::COFF:
4936   case Triple::ELF:
4937   case Triple::Wasm:
4938   case Triple::UnknownObjectFormat:
4939     return ".llvmcmd";
4940   case Triple::GOFF:
4941     llvm_unreachable("GOFF is not yet implemented");
4942     break;
4943   case Triple::SPIRV:
4944     llvm_unreachable("SPIRV is not yet implemented");
4945     break;
4946   case Triple::XCOFF:
4947     llvm_unreachable("XCOFF is not yet implemented");
4948     break;
4949   case Triple::DXContainer:
4950     llvm_unreachable("DXC is not yet implemented");
4951     break;
4952   }
4953   llvm_unreachable("Unimplemented ObjectFormatType");
4954 }
4955 
4956 void llvm::embedBitcodeInModule(llvm::Module &M, llvm::MemoryBufferRef Buf,
4957                                 bool EmbedBitcode, bool EmbedCmdline,
4958                                 const std::vector<uint8_t> &CmdArgs) {
4959   // Save llvm.compiler.used and remove it.
4960   SmallVector<Constant *, 2> UsedArray;
4961   SmallVector<GlobalValue *, 4> UsedGlobals;
4962   Type *UsedElementType = Type::getInt8Ty(M.getContext())->getPointerTo(0);
4963   GlobalVariable *Used = collectUsedGlobalVariables(M, UsedGlobals, true);
4964   for (auto *GV : UsedGlobals) {
4965     if (GV->getName() != "llvm.embedded.module" &&
4966         GV->getName() != "llvm.cmdline")
4967       UsedArray.push_back(
4968           ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
4969   }
4970   if (Used)
4971     Used->eraseFromParent();
4972 
4973   // Embed the bitcode for the llvm module.
4974   std::string Data;
4975   ArrayRef<uint8_t> ModuleData;
4976   Triple T(M.getTargetTriple());
4977 
4978   if (EmbedBitcode) {
4979     if (Buf.getBufferSize() == 0 ||
4980         !isBitcode((const unsigned char *)Buf.getBufferStart(),
4981                    (const unsigned char *)Buf.getBufferEnd())) {
4982       // If the input is LLVM Assembly, bitcode is produced by serializing
4983       // the module. Use-lists order need to be preserved in this case.
4984       llvm::raw_string_ostream OS(Data);
4985       llvm::WriteBitcodeToFile(M, OS, /* ShouldPreserveUseListOrder */ true);
4986       ModuleData =
4987           ArrayRef<uint8_t>((const uint8_t *)OS.str().data(), OS.str().size());
4988     } else
4989       // If the input is LLVM bitcode, write the input byte stream directly.
4990       ModuleData = ArrayRef<uint8_t>((const uint8_t *)Buf.getBufferStart(),
4991                                      Buf.getBufferSize());
4992   }
4993   llvm::Constant *ModuleConstant =
4994       llvm::ConstantDataArray::get(M.getContext(), ModuleData);
4995   llvm::GlobalVariable *GV = new llvm::GlobalVariable(
4996       M, ModuleConstant->getType(), true, llvm::GlobalValue::PrivateLinkage,
4997       ModuleConstant);
4998   GV->setSection(getSectionNameForBitcode(T));
4999   // Set alignment to 1 to prevent padding between two contributions from input
5000   // sections after linking.
5001   GV->setAlignment(Align(1));
5002   UsedArray.push_back(
5003       ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
5004   if (llvm::GlobalVariable *Old =
5005           M.getGlobalVariable("llvm.embedded.module", true)) {
5006     assert(Old->hasZeroLiveUses() &&
5007            "llvm.embedded.module can only be used once in llvm.compiler.used");
5008     GV->takeName(Old);
5009     Old->eraseFromParent();
5010   } else {
5011     GV->setName("llvm.embedded.module");
5012   }
5013 
5014   // Skip if only bitcode needs to be embedded.
5015   if (EmbedCmdline) {
5016     // Embed command-line options.
5017     ArrayRef<uint8_t> CmdData(const_cast<uint8_t *>(CmdArgs.data()),
5018                               CmdArgs.size());
5019     llvm::Constant *CmdConstant =
5020         llvm::ConstantDataArray::get(M.getContext(), CmdData);
5021     GV = new llvm::GlobalVariable(M, CmdConstant->getType(), true,
5022                                   llvm::GlobalValue::PrivateLinkage,
5023                                   CmdConstant);
5024     GV->setSection(getSectionNameForCommandline(T));
5025     GV->setAlignment(Align(1));
5026     UsedArray.push_back(
5027         ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
5028     if (llvm::GlobalVariable *Old = M.getGlobalVariable("llvm.cmdline", true)) {
5029       assert(Old->hasZeroLiveUses() &&
5030              "llvm.cmdline can only be used once in llvm.compiler.used");
5031       GV->takeName(Old);
5032       Old->eraseFromParent();
5033     } else {
5034       GV->setName("llvm.cmdline");
5035     }
5036   }
5037 
5038   if (UsedArray.empty())
5039     return;
5040 
5041   // Recreate llvm.compiler.used.
5042   ArrayType *ATy = ArrayType::get(UsedElementType, UsedArray.size());
5043   auto *NewUsed = new GlobalVariable(
5044       M, ATy, false, llvm::GlobalValue::AppendingLinkage,
5045       llvm::ConstantArray::get(ATy, UsedArray), "llvm.compiler.used");
5046   NewUsed->setSection("llvm.metadata");
5047 }
5048