xref: /llvm-project/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp (revision e53c4c6d8617145c4dd8d428bf47544ba4110eb5)
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 writeDIAssignID(const DIAssignID *N, SmallVectorImpl<uint64_t> &Record,
344                        unsigned Abbrev);
345   void writeDITemplateTypeParameter(const DITemplateTypeParameter *N,
346                                     SmallVectorImpl<uint64_t> &Record,
347                                     unsigned Abbrev);
348   void writeDITemplateValueParameter(const DITemplateValueParameter *N,
349                                      SmallVectorImpl<uint64_t> &Record,
350                                      unsigned Abbrev);
351   void writeDIGlobalVariable(const DIGlobalVariable *N,
352                              SmallVectorImpl<uint64_t> &Record,
353                              unsigned Abbrev);
354   void writeDILocalVariable(const DILocalVariable *N,
355                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
356   void writeDILabel(const DILabel *N,
357                     SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
358   void writeDIExpression(const DIExpression *N,
359                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
360   void writeDIGlobalVariableExpression(const DIGlobalVariableExpression *N,
361                                        SmallVectorImpl<uint64_t> &Record,
362                                        unsigned Abbrev);
363   void writeDIObjCProperty(const DIObjCProperty *N,
364                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
365   void writeDIImportedEntity(const DIImportedEntity *N,
366                              SmallVectorImpl<uint64_t> &Record,
367                              unsigned Abbrev);
368   unsigned createNamedMetadataAbbrev();
369   void writeNamedMetadata(SmallVectorImpl<uint64_t> &Record);
370   unsigned createMetadataStringsAbbrev();
371   void writeMetadataStrings(ArrayRef<const Metadata *> Strings,
372                             SmallVectorImpl<uint64_t> &Record);
373   void writeMetadataRecords(ArrayRef<const Metadata *> MDs,
374                             SmallVectorImpl<uint64_t> &Record,
375                             std::vector<unsigned> *MDAbbrevs = nullptr,
376                             std::vector<uint64_t> *IndexPos = nullptr);
377   void writeModuleMetadata();
378   void writeFunctionMetadata(const Function &F);
379   void writeFunctionMetadataAttachment(const Function &F);
380   void pushGlobalMetadataAttachment(SmallVectorImpl<uint64_t> &Record,
381                                     const GlobalObject &GO);
382   void writeModuleMetadataKinds();
383   void writeOperandBundleTags();
384   void writeSyncScopeNames();
385   void writeConstants(unsigned FirstVal, unsigned LastVal, bool isGlobal);
386   void writeModuleConstants();
387   bool pushValueAndType(const Value *V, unsigned InstID,
388                         SmallVectorImpl<unsigned> &Vals);
389   void writeOperandBundles(const CallBase &CB, unsigned InstID);
390   void pushValue(const Value *V, unsigned InstID,
391                  SmallVectorImpl<unsigned> &Vals);
392   void pushValueSigned(const Value *V, unsigned InstID,
393                        SmallVectorImpl<uint64_t> &Vals);
394   void writeInstruction(const Instruction &I, unsigned InstID,
395                         SmallVectorImpl<unsigned> &Vals);
396   void writeFunctionLevelValueSymbolTable(const ValueSymbolTable &VST);
397   void writeGlobalValueSymbolTable(
398       DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
399   void writeUseList(UseListOrder &&Order);
400   void writeUseListBlock(const Function *F);
401   void
402   writeFunction(const Function &F,
403                 DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
404   void writeBlockInfo();
405   void writeModuleHash(size_t BlockStartPos);
406 
407   unsigned getEncodedSyncScopeID(SyncScope::ID SSID) {
408     return unsigned(SSID);
409   }
410 
411   unsigned getEncodedAlign(MaybeAlign Alignment) { return encode(Alignment); }
412 };
413 
414 /// Class to manage the bitcode writing for a combined index.
415 class IndexBitcodeWriter : public BitcodeWriterBase {
416   /// The combined index to write to bitcode.
417   const ModuleSummaryIndex &Index;
418 
419   /// When writing a subset of the index for distributed backends, client
420   /// provides a map of modules to the corresponding GUIDs/summaries to write.
421   const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex;
422 
423   /// Map that holds the correspondence between the GUID used in the combined
424   /// index and a value id generated by this class to use in references.
425   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
426 
427   /// Tracks the last value id recorded in the GUIDToValueMap.
428   unsigned GlobalValueId = 0;
429 
430 public:
431   /// Constructs a IndexBitcodeWriter object for the given combined index,
432   /// writing to the provided \p Buffer. When writing a subset of the index
433   /// for a distributed backend, provide a \p ModuleToSummariesForIndex map.
434   IndexBitcodeWriter(BitstreamWriter &Stream, StringTableBuilder &StrtabBuilder,
435                      const ModuleSummaryIndex &Index,
436                      const std::map<std::string, GVSummaryMapTy>
437                          *ModuleToSummariesForIndex = nullptr)
438       : BitcodeWriterBase(Stream, StrtabBuilder), Index(Index),
439         ModuleToSummariesForIndex(ModuleToSummariesForIndex) {
440     // Assign unique value ids to all summaries to be written, for use
441     // in writing out the call graph edges. Save the mapping from GUID
442     // to the new global value id to use when writing those edges, which
443     // are currently saved in the index in terms of GUID.
444     forEachSummary([&](GVInfo I, bool) {
445       GUIDToValueIdMap[I.first] = ++GlobalValueId;
446     });
447   }
448 
449   /// The below iterator returns the GUID and associated summary.
450   using GVInfo = std::pair<GlobalValue::GUID, GlobalValueSummary *>;
451 
452   /// Calls the callback for each value GUID and summary to be written to
453   /// bitcode. This hides the details of whether they are being pulled from the
454   /// entire index or just those in a provided ModuleToSummariesForIndex map.
455   template<typename Functor>
456   void forEachSummary(Functor Callback) {
457     if (ModuleToSummariesForIndex) {
458       for (auto &M : *ModuleToSummariesForIndex)
459         for (auto &Summary : M.second) {
460           Callback(Summary, false);
461           // Ensure aliasee is handled, e.g. for assigning a valueId,
462           // even if we are not importing the aliasee directly (the
463           // imported alias will contain a copy of aliasee).
464           if (auto *AS = dyn_cast<AliasSummary>(Summary.getSecond()))
465             Callback({AS->getAliaseeGUID(), &AS->getAliasee()}, true);
466         }
467     } else {
468       for (auto &Summaries : Index)
469         for (auto &Summary : Summaries.second.SummaryList)
470           Callback({Summaries.first, Summary.get()}, false);
471     }
472   }
473 
474   /// Calls the callback for each entry in the modulePaths StringMap that
475   /// should be written to the module path string table. This hides the details
476   /// of whether they are being pulled from the entire index or just those in a
477   /// provided ModuleToSummariesForIndex map.
478   template <typename Functor> void forEachModule(Functor Callback) {
479     if (ModuleToSummariesForIndex) {
480       for (const auto &M : *ModuleToSummariesForIndex) {
481         const auto &MPI = Index.modulePaths().find(M.first);
482         if (MPI == Index.modulePaths().end()) {
483           // This should only happen if the bitcode file was empty, in which
484           // case we shouldn't be importing (the ModuleToSummariesForIndex
485           // would only include the module we are writing and index for).
486           assert(ModuleToSummariesForIndex->size() == 1);
487           continue;
488         }
489         Callback(*MPI);
490       }
491     } else {
492       for (const auto &MPSE : Index.modulePaths())
493         Callback(MPSE);
494     }
495   }
496 
497   /// Main entry point for writing a combined index to bitcode.
498   void write();
499 
500 private:
501   void writeModStrings();
502   void writeCombinedGlobalValueSummary();
503 
504   Optional<unsigned> getValueId(GlobalValue::GUID ValGUID) {
505     auto VMI = GUIDToValueIdMap.find(ValGUID);
506     if (VMI == GUIDToValueIdMap.end())
507       return None;
508     return VMI->second;
509   }
510 
511   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
512 };
513 
514 } // end anonymous namespace
515 
516 static unsigned getEncodedCastOpcode(unsigned Opcode) {
517   switch (Opcode) {
518   default: llvm_unreachable("Unknown cast instruction!");
519   case Instruction::Trunc   : return bitc::CAST_TRUNC;
520   case Instruction::ZExt    : return bitc::CAST_ZEXT;
521   case Instruction::SExt    : return bitc::CAST_SEXT;
522   case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
523   case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
524   case Instruction::UIToFP  : return bitc::CAST_UITOFP;
525   case Instruction::SIToFP  : return bitc::CAST_SITOFP;
526   case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
527   case Instruction::FPExt   : return bitc::CAST_FPEXT;
528   case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
529   case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
530   case Instruction::BitCast : return bitc::CAST_BITCAST;
531   case Instruction::AddrSpaceCast: return bitc::CAST_ADDRSPACECAST;
532   }
533 }
534 
535 static unsigned getEncodedUnaryOpcode(unsigned Opcode) {
536   switch (Opcode) {
537   default: llvm_unreachable("Unknown binary instruction!");
538   case Instruction::FNeg: return bitc::UNOP_FNEG;
539   }
540 }
541 
542 static unsigned getEncodedBinaryOpcode(unsigned Opcode) {
543   switch (Opcode) {
544   default: llvm_unreachable("Unknown binary instruction!");
545   case Instruction::Add:
546   case Instruction::FAdd: return bitc::BINOP_ADD;
547   case Instruction::Sub:
548   case Instruction::FSub: return bitc::BINOP_SUB;
549   case Instruction::Mul:
550   case Instruction::FMul: return bitc::BINOP_MUL;
551   case Instruction::UDiv: return bitc::BINOP_UDIV;
552   case Instruction::FDiv:
553   case Instruction::SDiv: return bitc::BINOP_SDIV;
554   case Instruction::URem: return bitc::BINOP_UREM;
555   case Instruction::FRem:
556   case Instruction::SRem: return bitc::BINOP_SREM;
557   case Instruction::Shl:  return bitc::BINOP_SHL;
558   case Instruction::LShr: return bitc::BINOP_LSHR;
559   case Instruction::AShr: return bitc::BINOP_ASHR;
560   case Instruction::And:  return bitc::BINOP_AND;
561   case Instruction::Or:   return bitc::BINOP_OR;
562   case Instruction::Xor:  return bitc::BINOP_XOR;
563   }
564 }
565 
566 static unsigned getEncodedRMWOperation(AtomicRMWInst::BinOp Op) {
567   switch (Op) {
568   default: llvm_unreachable("Unknown RMW operation!");
569   case AtomicRMWInst::Xchg: return bitc::RMW_XCHG;
570   case AtomicRMWInst::Add: return bitc::RMW_ADD;
571   case AtomicRMWInst::Sub: return bitc::RMW_SUB;
572   case AtomicRMWInst::And: return bitc::RMW_AND;
573   case AtomicRMWInst::Nand: return bitc::RMW_NAND;
574   case AtomicRMWInst::Or: return bitc::RMW_OR;
575   case AtomicRMWInst::Xor: return bitc::RMW_XOR;
576   case AtomicRMWInst::Max: return bitc::RMW_MAX;
577   case AtomicRMWInst::Min: return bitc::RMW_MIN;
578   case AtomicRMWInst::UMax: return bitc::RMW_UMAX;
579   case AtomicRMWInst::UMin: return bitc::RMW_UMIN;
580   case AtomicRMWInst::FAdd: return bitc::RMW_FADD;
581   case AtomicRMWInst::FSub: return bitc::RMW_FSUB;
582   case AtomicRMWInst::FMax: return bitc::RMW_FMAX;
583   case AtomicRMWInst::FMin: return bitc::RMW_FMIN;
584   }
585 }
586 
587 static unsigned getEncodedOrdering(AtomicOrdering Ordering) {
588   switch (Ordering) {
589   case AtomicOrdering::NotAtomic: return bitc::ORDERING_NOTATOMIC;
590   case AtomicOrdering::Unordered: return bitc::ORDERING_UNORDERED;
591   case AtomicOrdering::Monotonic: return bitc::ORDERING_MONOTONIC;
592   case AtomicOrdering::Acquire: return bitc::ORDERING_ACQUIRE;
593   case AtomicOrdering::Release: return bitc::ORDERING_RELEASE;
594   case AtomicOrdering::AcquireRelease: return bitc::ORDERING_ACQREL;
595   case AtomicOrdering::SequentiallyConsistent: return bitc::ORDERING_SEQCST;
596   }
597   llvm_unreachable("Invalid ordering");
598 }
599 
600 static void writeStringRecord(BitstreamWriter &Stream, unsigned Code,
601                               StringRef Str, unsigned AbbrevToUse) {
602   SmallVector<unsigned, 64> Vals;
603 
604   // Code: [strchar x N]
605   for (char C : Str) {
606     if (AbbrevToUse && !BitCodeAbbrevOp::isChar6(C))
607       AbbrevToUse = 0;
608     Vals.push_back(C);
609   }
610 
611   // Emit the finished record.
612   Stream.EmitRecord(Code, Vals, AbbrevToUse);
613 }
614 
615 static uint64_t getAttrKindEncoding(Attribute::AttrKind Kind) {
616   switch (Kind) {
617   case Attribute::Alignment:
618     return bitc::ATTR_KIND_ALIGNMENT;
619   case Attribute::AllocAlign:
620     return bitc::ATTR_KIND_ALLOC_ALIGN;
621   case Attribute::AllocSize:
622     return bitc::ATTR_KIND_ALLOC_SIZE;
623   case Attribute::AlwaysInline:
624     return bitc::ATTR_KIND_ALWAYS_INLINE;
625   case Attribute::ArgMemOnly:
626     return bitc::ATTR_KIND_ARGMEMONLY;
627   case Attribute::Builtin:
628     return bitc::ATTR_KIND_BUILTIN;
629   case Attribute::ByVal:
630     return bitc::ATTR_KIND_BY_VAL;
631   case Attribute::Convergent:
632     return bitc::ATTR_KIND_CONVERGENT;
633   case Attribute::InAlloca:
634     return bitc::ATTR_KIND_IN_ALLOCA;
635   case Attribute::Cold:
636     return bitc::ATTR_KIND_COLD;
637   case Attribute::DisableSanitizerInstrumentation:
638     return bitc::ATTR_KIND_DISABLE_SANITIZER_INSTRUMENTATION;
639   case Attribute::FnRetThunkExtern:
640     return bitc::ATTR_KIND_FNRETTHUNK_EXTERN;
641   case Attribute::Hot:
642     return bitc::ATTR_KIND_HOT;
643   case Attribute::ElementType:
644     return bitc::ATTR_KIND_ELEMENTTYPE;
645   case Attribute::InaccessibleMemOnly:
646     return bitc::ATTR_KIND_INACCESSIBLEMEM_ONLY;
647   case Attribute::InaccessibleMemOrArgMemOnly:
648     return bitc::ATTR_KIND_INACCESSIBLEMEM_OR_ARGMEMONLY;
649   case Attribute::InlineHint:
650     return bitc::ATTR_KIND_INLINE_HINT;
651   case Attribute::InReg:
652     return bitc::ATTR_KIND_IN_REG;
653   case Attribute::JumpTable:
654     return bitc::ATTR_KIND_JUMP_TABLE;
655   case Attribute::MinSize:
656     return bitc::ATTR_KIND_MIN_SIZE;
657   case Attribute::AllocatedPointer:
658     return bitc::ATTR_KIND_ALLOCATED_POINTER;
659   case Attribute::AllocKind:
660     return bitc::ATTR_KIND_ALLOC_KIND;
661   case Attribute::Memory:
662     return bitc::ATTR_KIND_MEMORY;
663   case Attribute::Naked:
664     return bitc::ATTR_KIND_NAKED;
665   case Attribute::Nest:
666     return bitc::ATTR_KIND_NEST;
667   case Attribute::NoAlias:
668     return bitc::ATTR_KIND_NO_ALIAS;
669   case Attribute::NoBuiltin:
670     return bitc::ATTR_KIND_NO_BUILTIN;
671   case Attribute::NoCallback:
672     return bitc::ATTR_KIND_NO_CALLBACK;
673   case Attribute::NoCapture:
674     return bitc::ATTR_KIND_NO_CAPTURE;
675   case Attribute::NoDuplicate:
676     return bitc::ATTR_KIND_NO_DUPLICATE;
677   case Attribute::NoFree:
678     return bitc::ATTR_KIND_NOFREE;
679   case Attribute::NoImplicitFloat:
680     return bitc::ATTR_KIND_NO_IMPLICIT_FLOAT;
681   case Attribute::NoInline:
682     return bitc::ATTR_KIND_NO_INLINE;
683   case Attribute::NoRecurse:
684     return bitc::ATTR_KIND_NO_RECURSE;
685   case Attribute::NoMerge:
686     return bitc::ATTR_KIND_NO_MERGE;
687   case Attribute::NonLazyBind:
688     return bitc::ATTR_KIND_NON_LAZY_BIND;
689   case Attribute::NonNull:
690     return bitc::ATTR_KIND_NON_NULL;
691   case Attribute::Dereferenceable:
692     return bitc::ATTR_KIND_DEREFERENCEABLE;
693   case Attribute::DereferenceableOrNull:
694     return bitc::ATTR_KIND_DEREFERENCEABLE_OR_NULL;
695   case Attribute::NoRedZone:
696     return bitc::ATTR_KIND_NO_RED_ZONE;
697   case Attribute::NoReturn:
698     return bitc::ATTR_KIND_NO_RETURN;
699   case Attribute::NoSync:
700     return bitc::ATTR_KIND_NOSYNC;
701   case Attribute::NoCfCheck:
702     return bitc::ATTR_KIND_NOCF_CHECK;
703   case Attribute::NoProfile:
704     return bitc::ATTR_KIND_NO_PROFILE;
705   case Attribute::SkipProfile:
706     return bitc::ATTR_KIND_SKIP_PROFILE;
707   case Attribute::NoUnwind:
708     return bitc::ATTR_KIND_NO_UNWIND;
709   case Attribute::NoSanitizeBounds:
710     return bitc::ATTR_KIND_NO_SANITIZE_BOUNDS;
711   case Attribute::NoSanitizeCoverage:
712     return bitc::ATTR_KIND_NO_SANITIZE_COVERAGE;
713   case Attribute::NullPointerIsValid:
714     return bitc::ATTR_KIND_NULL_POINTER_IS_VALID;
715   case Attribute::OptForFuzzing:
716     return bitc::ATTR_KIND_OPT_FOR_FUZZING;
717   case Attribute::OptimizeForSize:
718     return bitc::ATTR_KIND_OPTIMIZE_FOR_SIZE;
719   case Attribute::OptimizeNone:
720     return bitc::ATTR_KIND_OPTIMIZE_NONE;
721   case Attribute::ReadNone:
722     return bitc::ATTR_KIND_READ_NONE;
723   case Attribute::ReadOnly:
724     return bitc::ATTR_KIND_READ_ONLY;
725   case Attribute::Returned:
726     return bitc::ATTR_KIND_RETURNED;
727   case Attribute::ReturnsTwice:
728     return bitc::ATTR_KIND_RETURNS_TWICE;
729   case Attribute::SExt:
730     return bitc::ATTR_KIND_S_EXT;
731   case Attribute::Speculatable:
732     return bitc::ATTR_KIND_SPECULATABLE;
733   case Attribute::StackAlignment:
734     return bitc::ATTR_KIND_STACK_ALIGNMENT;
735   case Attribute::StackProtect:
736     return bitc::ATTR_KIND_STACK_PROTECT;
737   case Attribute::StackProtectReq:
738     return bitc::ATTR_KIND_STACK_PROTECT_REQ;
739   case Attribute::StackProtectStrong:
740     return bitc::ATTR_KIND_STACK_PROTECT_STRONG;
741   case Attribute::SafeStack:
742     return bitc::ATTR_KIND_SAFESTACK;
743   case Attribute::ShadowCallStack:
744     return bitc::ATTR_KIND_SHADOWCALLSTACK;
745   case Attribute::StrictFP:
746     return bitc::ATTR_KIND_STRICT_FP;
747   case Attribute::StructRet:
748     return bitc::ATTR_KIND_STRUCT_RET;
749   case Attribute::SanitizeAddress:
750     return bitc::ATTR_KIND_SANITIZE_ADDRESS;
751   case Attribute::SanitizeHWAddress:
752     return bitc::ATTR_KIND_SANITIZE_HWADDRESS;
753   case Attribute::SanitizeThread:
754     return bitc::ATTR_KIND_SANITIZE_THREAD;
755   case Attribute::SanitizeMemory:
756     return bitc::ATTR_KIND_SANITIZE_MEMORY;
757   case Attribute::SpeculativeLoadHardening:
758     return bitc::ATTR_KIND_SPECULATIVE_LOAD_HARDENING;
759   case Attribute::SwiftError:
760     return bitc::ATTR_KIND_SWIFT_ERROR;
761   case Attribute::SwiftSelf:
762     return bitc::ATTR_KIND_SWIFT_SELF;
763   case Attribute::SwiftAsync:
764     return bitc::ATTR_KIND_SWIFT_ASYNC;
765   case Attribute::UWTable:
766     return bitc::ATTR_KIND_UW_TABLE;
767   case Attribute::VScaleRange:
768     return bitc::ATTR_KIND_VSCALE_RANGE;
769   case Attribute::WillReturn:
770     return bitc::ATTR_KIND_WILLRETURN;
771   case Attribute::WriteOnly:
772     return bitc::ATTR_KIND_WRITEONLY;
773   case Attribute::ZExt:
774     return bitc::ATTR_KIND_Z_EXT;
775   case Attribute::ImmArg:
776     return bitc::ATTR_KIND_IMMARG;
777   case Attribute::SanitizeMemTag:
778     return bitc::ATTR_KIND_SANITIZE_MEMTAG;
779   case Attribute::Preallocated:
780     return bitc::ATTR_KIND_PREALLOCATED;
781   case Attribute::NoUndef:
782     return bitc::ATTR_KIND_NOUNDEF;
783   case Attribute::ByRef:
784     return bitc::ATTR_KIND_BYREF;
785   case Attribute::MustProgress:
786     return bitc::ATTR_KIND_MUSTPROGRESS;
787   case Attribute::PresplitCoroutine:
788     return bitc::ATTR_KIND_PRESPLIT_COROUTINE;
789   case Attribute::EndAttrKinds:
790     llvm_unreachable("Can not encode end-attribute kinds marker.");
791   case Attribute::None:
792     llvm_unreachable("Can not encode none-attribute.");
793   case Attribute::EmptyKey:
794   case Attribute::TombstoneKey:
795     llvm_unreachable("Trying to encode EmptyKey/TombstoneKey");
796   }
797 
798   llvm_unreachable("Trying to encode unknown attribute");
799 }
800 
801 void ModuleBitcodeWriter::writeAttributeGroupTable() {
802   const std::vector<ValueEnumerator::IndexAndAttrSet> &AttrGrps =
803       VE.getAttributeGroups();
804   if (AttrGrps.empty()) return;
805 
806   Stream.EnterSubblock(bitc::PARAMATTR_GROUP_BLOCK_ID, 3);
807 
808   SmallVector<uint64_t, 64> Record;
809   for (ValueEnumerator::IndexAndAttrSet Pair : AttrGrps) {
810     unsigned AttrListIndex = Pair.first;
811     AttributeSet AS = Pair.second;
812     Record.push_back(VE.getAttributeGroupID(Pair));
813     Record.push_back(AttrListIndex);
814 
815     for (Attribute Attr : AS) {
816       if (Attr.isEnumAttribute()) {
817         Record.push_back(0);
818         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
819       } else if (Attr.isIntAttribute()) {
820         Record.push_back(1);
821         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
822         Record.push_back(Attr.getValueAsInt());
823       } else if (Attr.isStringAttribute()) {
824         StringRef Kind = Attr.getKindAsString();
825         StringRef Val = Attr.getValueAsString();
826 
827         Record.push_back(Val.empty() ? 3 : 4);
828         Record.append(Kind.begin(), Kind.end());
829         Record.push_back(0);
830         if (!Val.empty()) {
831           Record.append(Val.begin(), Val.end());
832           Record.push_back(0);
833         }
834       } else {
835         assert(Attr.isTypeAttribute());
836         Type *Ty = Attr.getValueAsType();
837         Record.push_back(Ty ? 6 : 5);
838         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
839         if (Ty)
840           Record.push_back(VE.getTypeID(Attr.getValueAsType()));
841       }
842     }
843 
844     Stream.EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
845     Record.clear();
846   }
847 
848   Stream.ExitBlock();
849 }
850 
851 void ModuleBitcodeWriter::writeAttributeTable() {
852   const std::vector<AttributeList> &Attrs = VE.getAttributeLists();
853   if (Attrs.empty()) return;
854 
855   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
856 
857   SmallVector<uint64_t, 64> Record;
858   for (const AttributeList &AL : Attrs) {
859     for (unsigned i : AL.indexes()) {
860       AttributeSet AS = AL.getAttributes(i);
861       if (AS.hasAttributes())
862         Record.push_back(VE.getAttributeGroupID({i, AS}));
863     }
864 
865     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
866     Record.clear();
867   }
868 
869   Stream.ExitBlock();
870 }
871 
872 /// WriteTypeTable - Write out the type table for a module.
873 void ModuleBitcodeWriter::writeTypeTable() {
874   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
875 
876   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
877   SmallVector<uint64_t, 64> TypeVals;
878 
879   uint64_t NumBits = VE.computeBitsRequiredForTypeIndicies();
880 
881   // Abbrev for TYPE_CODE_POINTER.
882   auto Abbv = std::make_shared<BitCodeAbbrev>();
883   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
884   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
885   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
886   unsigned PtrAbbrev = Stream.EmitAbbrev(std::move(Abbv));
887 
888   // Abbrev for TYPE_CODE_OPAQUE_POINTER.
889   Abbv = std::make_shared<BitCodeAbbrev>();
890   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_OPAQUE_POINTER));
891   Abbv->Add(BitCodeAbbrevOp(0)); // Addrspace = 0
892   unsigned OpaquePtrAbbrev = Stream.EmitAbbrev(std::move(Abbv));
893 
894   // Abbrev for TYPE_CODE_FUNCTION.
895   Abbv = std::make_shared<BitCodeAbbrev>();
896   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
897   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
898   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
899   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
900   unsigned FunctionAbbrev = Stream.EmitAbbrev(std::move(Abbv));
901 
902   // Abbrev for TYPE_CODE_STRUCT_ANON.
903   Abbv = std::make_shared<BitCodeAbbrev>();
904   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
905   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
906   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
907   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
908   unsigned StructAnonAbbrev = Stream.EmitAbbrev(std::move(Abbv));
909 
910   // Abbrev for TYPE_CODE_STRUCT_NAME.
911   Abbv = std::make_shared<BitCodeAbbrev>();
912   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
913   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
914   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
915   unsigned StructNameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
916 
917   // Abbrev for TYPE_CODE_STRUCT_NAMED.
918   Abbv = std::make_shared<BitCodeAbbrev>();
919   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
920   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
921   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
922   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
923   unsigned StructNamedAbbrev = Stream.EmitAbbrev(std::move(Abbv));
924 
925   // Abbrev for TYPE_CODE_ARRAY.
926   Abbv = std::make_shared<BitCodeAbbrev>();
927   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
928   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
929   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
930   unsigned ArrayAbbrev = Stream.EmitAbbrev(std::move(Abbv));
931 
932   // Emit an entry count so the reader can reserve space.
933   TypeVals.push_back(TypeList.size());
934   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
935   TypeVals.clear();
936 
937   // Loop over all of the types, emitting each in turn.
938   for (Type *T : TypeList) {
939     int AbbrevToUse = 0;
940     unsigned Code = 0;
941 
942     switch (T->getTypeID()) {
943     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;      break;
944     case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;      break;
945     case Type::BFloatTyID:    Code = bitc::TYPE_CODE_BFLOAT;    break;
946     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;     break;
947     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE;    break;
948     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80;  break;
949     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128;     break;
950     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
951     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;     break;
952     case Type::MetadataTyID:  Code = bitc::TYPE_CODE_METADATA;  break;
953     case Type::X86_MMXTyID:   Code = bitc::TYPE_CODE_X86_MMX;   break;
954     case Type::X86_AMXTyID:   Code = bitc::TYPE_CODE_X86_AMX;   break;
955     case Type::TokenTyID:     Code = bitc::TYPE_CODE_TOKEN;     break;
956     case Type::IntegerTyID:
957       // INTEGER: [width]
958       Code = bitc::TYPE_CODE_INTEGER;
959       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
960       break;
961     case Type::PointerTyID: {
962       PointerType *PTy = cast<PointerType>(T);
963       unsigned AddressSpace = PTy->getAddressSpace();
964       if (PTy->isOpaque()) {
965         // OPAQUE_POINTER: [address space]
966         Code = bitc::TYPE_CODE_OPAQUE_POINTER;
967         TypeVals.push_back(AddressSpace);
968         if (AddressSpace == 0)
969           AbbrevToUse = OpaquePtrAbbrev;
970       } else {
971         // POINTER: [pointee type, address space]
972         Code = bitc::TYPE_CODE_POINTER;
973         TypeVals.push_back(VE.getTypeID(PTy->getNonOpaquePointerElementType()));
974         TypeVals.push_back(AddressSpace);
975         if (AddressSpace == 0)
976           AbbrevToUse = PtrAbbrev;
977       }
978       break;
979     }
980     case Type::FunctionTyID: {
981       FunctionType *FT = cast<FunctionType>(T);
982       // FUNCTION: [isvararg, retty, paramty x N]
983       Code = bitc::TYPE_CODE_FUNCTION;
984       TypeVals.push_back(FT->isVarArg());
985       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
986       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
987         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
988       AbbrevToUse = FunctionAbbrev;
989       break;
990     }
991     case Type::StructTyID: {
992       StructType *ST = cast<StructType>(T);
993       // STRUCT: [ispacked, eltty x N]
994       TypeVals.push_back(ST->isPacked());
995       // Output all of the element types.
996       for (Type *ET : ST->elements())
997         TypeVals.push_back(VE.getTypeID(ET));
998 
999       if (ST->isLiteral()) {
1000         Code = bitc::TYPE_CODE_STRUCT_ANON;
1001         AbbrevToUse = StructAnonAbbrev;
1002       } else {
1003         if (ST->isOpaque()) {
1004           Code = bitc::TYPE_CODE_OPAQUE;
1005         } else {
1006           Code = bitc::TYPE_CODE_STRUCT_NAMED;
1007           AbbrevToUse = StructNamedAbbrev;
1008         }
1009 
1010         // Emit the name if it is present.
1011         if (!ST->getName().empty())
1012           writeStringRecord(Stream, bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
1013                             StructNameAbbrev);
1014       }
1015       break;
1016     }
1017     case Type::ArrayTyID: {
1018       ArrayType *AT = cast<ArrayType>(T);
1019       // ARRAY: [numelts, eltty]
1020       Code = bitc::TYPE_CODE_ARRAY;
1021       TypeVals.push_back(AT->getNumElements());
1022       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
1023       AbbrevToUse = ArrayAbbrev;
1024       break;
1025     }
1026     case Type::FixedVectorTyID:
1027     case Type::ScalableVectorTyID: {
1028       VectorType *VT = cast<VectorType>(T);
1029       // VECTOR [numelts, eltty] or
1030       //        [numelts, eltty, scalable]
1031       Code = bitc::TYPE_CODE_VECTOR;
1032       TypeVals.push_back(VT->getElementCount().getKnownMinValue());
1033       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
1034       if (isa<ScalableVectorType>(VT))
1035         TypeVals.push_back(true);
1036       break;
1037     }
1038     case Type::TypedPointerTyID:
1039       llvm_unreachable("Typed pointers cannot be added to IR modules");
1040     }
1041 
1042     // Emit the finished record.
1043     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
1044     TypeVals.clear();
1045   }
1046 
1047   Stream.ExitBlock();
1048 }
1049 
1050 static unsigned getEncodedLinkage(const GlobalValue::LinkageTypes Linkage) {
1051   switch (Linkage) {
1052   case GlobalValue::ExternalLinkage:
1053     return 0;
1054   case GlobalValue::WeakAnyLinkage:
1055     return 16;
1056   case GlobalValue::AppendingLinkage:
1057     return 2;
1058   case GlobalValue::InternalLinkage:
1059     return 3;
1060   case GlobalValue::LinkOnceAnyLinkage:
1061     return 18;
1062   case GlobalValue::ExternalWeakLinkage:
1063     return 7;
1064   case GlobalValue::CommonLinkage:
1065     return 8;
1066   case GlobalValue::PrivateLinkage:
1067     return 9;
1068   case GlobalValue::WeakODRLinkage:
1069     return 17;
1070   case GlobalValue::LinkOnceODRLinkage:
1071     return 19;
1072   case GlobalValue::AvailableExternallyLinkage:
1073     return 12;
1074   }
1075   llvm_unreachable("Invalid linkage");
1076 }
1077 
1078 static unsigned getEncodedLinkage(const GlobalValue &GV) {
1079   return getEncodedLinkage(GV.getLinkage());
1080 }
1081 
1082 static uint64_t getEncodedFFlags(FunctionSummary::FFlags Flags) {
1083   uint64_t RawFlags = 0;
1084   RawFlags |= Flags.ReadNone;
1085   RawFlags |= (Flags.ReadOnly << 1);
1086   RawFlags |= (Flags.NoRecurse << 2);
1087   RawFlags |= (Flags.ReturnDoesNotAlias << 3);
1088   RawFlags |= (Flags.NoInline << 4);
1089   RawFlags |= (Flags.AlwaysInline << 5);
1090   RawFlags |= (Flags.NoUnwind << 6);
1091   RawFlags |= (Flags.MayThrow << 7);
1092   RawFlags |= (Flags.HasUnknownCall << 8);
1093   RawFlags |= (Flags.MustBeUnreachable << 9);
1094   return RawFlags;
1095 }
1096 
1097 // Decode the flags for GlobalValue in the summary. See getDecodedGVSummaryFlags
1098 // in BitcodeReader.cpp.
1099 static uint64_t getEncodedGVSummaryFlags(GlobalValueSummary::GVFlags Flags) {
1100   uint64_t RawFlags = 0;
1101 
1102   RawFlags |= Flags.NotEligibleToImport; // bool
1103   RawFlags |= (Flags.Live << 1);
1104   RawFlags |= (Flags.DSOLocal << 2);
1105   RawFlags |= (Flags.CanAutoHide << 3);
1106 
1107   // Linkage don't need to be remapped at that time for the summary. Any future
1108   // change to the getEncodedLinkage() function will need to be taken into
1109   // account here as well.
1110   RawFlags = (RawFlags << 4) | Flags.Linkage; // 4 bits
1111 
1112   RawFlags |= (Flags.Visibility << 8); // 2 bits
1113 
1114   return RawFlags;
1115 }
1116 
1117 static uint64_t getEncodedGVarFlags(GlobalVarSummary::GVarFlags Flags) {
1118   uint64_t RawFlags = Flags.MaybeReadOnly | (Flags.MaybeWriteOnly << 1) |
1119                       (Flags.Constant << 2) | Flags.VCallVisibility << 3;
1120   return RawFlags;
1121 }
1122 
1123 static unsigned getEncodedVisibility(const GlobalValue &GV) {
1124   switch (GV.getVisibility()) {
1125   case GlobalValue::DefaultVisibility:   return 0;
1126   case GlobalValue::HiddenVisibility:    return 1;
1127   case GlobalValue::ProtectedVisibility: return 2;
1128   }
1129   llvm_unreachable("Invalid visibility");
1130 }
1131 
1132 static unsigned getEncodedDLLStorageClass(const GlobalValue &GV) {
1133   switch (GV.getDLLStorageClass()) {
1134   case GlobalValue::DefaultStorageClass:   return 0;
1135   case GlobalValue::DLLImportStorageClass: return 1;
1136   case GlobalValue::DLLExportStorageClass: return 2;
1137   }
1138   llvm_unreachable("Invalid DLL storage class");
1139 }
1140 
1141 static unsigned getEncodedThreadLocalMode(const GlobalValue &GV) {
1142   switch (GV.getThreadLocalMode()) {
1143     case GlobalVariable::NotThreadLocal:         return 0;
1144     case GlobalVariable::GeneralDynamicTLSModel: return 1;
1145     case GlobalVariable::LocalDynamicTLSModel:   return 2;
1146     case GlobalVariable::InitialExecTLSModel:    return 3;
1147     case GlobalVariable::LocalExecTLSModel:      return 4;
1148   }
1149   llvm_unreachable("Invalid TLS model");
1150 }
1151 
1152 static unsigned getEncodedComdatSelectionKind(const Comdat &C) {
1153   switch (C.getSelectionKind()) {
1154   case Comdat::Any:
1155     return bitc::COMDAT_SELECTION_KIND_ANY;
1156   case Comdat::ExactMatch:
1157     return bitc::COMDAT_SELECTION_KIND_EXACT_MATCH;
1158   case Comdat::Largest:
1159     return bitc::COMDAT_SELECTION_KIND_LARGEST;
1160   case Comdat::NoDeduplicate:
1161     return bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES;
1162   case Comdat::SameSize:
1163     return bitc::COMDAT_SELECTION_KIND_SAME_SIZE;
1164   }
1165   llvm_unreachable("Invalid selection kind");
1166 }
1167 
1168 static unsigned getEncodedUnnamedAddr(const GlobalValue &GV) {
1169   switch (GV.getUnnamedAddr()) {
1170   case GlobalValue::UnnamedAddr::None:   return 0;
1171   case GlobalValue::UnnamedAddr::Local:  return 2;
1172   case GlobalValue::UnnamedAddr::Global: return 1;
1173   }
1174   llvm_unreachable("Invalid unnamed_addr");
1175 }
1176 
1177 size_t ModuleBitcodeWriter::addToStrtab(StringRef Str) {
1178   if (GenerateHash)
1179     Hasher.update(Str);
1180   return StrtabBuilder.add(Str);
1181 }
1182 
1183 void ModuleBitcodeWriter::writeComdats() {
1184   SmallVector<unsigned, 64> Vals;
1185   for (const Comdat *C : VE.getComdats()) {
1186     // COMDAT: [strtab offset, strtab size, selection_kind]
1187     Vals.push_back(addToStrtab(C->getName()));
1188     Vals.push_back(C->getName().size());
1189     Vals.push_back(getEncodedComdatSelectionKind(*C));
1190     Stream.EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
1191     Vals.clear();
1192   }
1193 }
1194 
1195 /// Write a record that will eventually hold the word offset of the
1196 /// module-level VST. For now the offset is 0, which will be backpatched
1197 /// after the real VST is written. Saves the bit offset to backpatch.
1198 void ModuleBitcodeWriter::writeValueSymbolTableForwardDecl() {
1199   // Write a placeholder value in for the offset of the real VST,
1200   // which is written after the function blocks so that it can include
1201   // the offset of each function. The placeholder offset will be
1202   // updated when the real VST is written.
1203   auto Abbv = std::make_shared<BitCodeAbbrev>();
1204   Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_VSTOFFSET));
1205   // Blocks are 32-bit aligned, so we can use a 32-bit word offset to
1206   // hold the real VST offset. Must use fixed instead of VBR as we don't
1207   // know how many VBR chunks to reserve ahead of time.
1208   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
1209   unsigned VSTOffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1210 
1211   // Emit the placeholder
1212   uint64_t Vals[] = {bitc::MODULE_CODE_VSTOFFSET, 0};
1213   Stream.EmitRecordWithAbbrev(VSTOffsetAbbrev, Vals);
1214 
1215   // Compute and save the bit offset to the placeholder, which will be
1216   // patched when the real VST is written. We can simply subtract the 32-bit
1217   // fixed size from the current bit number to get the location to backpatch.
1218   VSTOffsetPlaceholder = Stream.GetCurrentBitNo() - 32;
1219 }
1220 
1221 enum StringEncoding { SE_Char6, SE_Fixed7, SE_Fixed8 };
1222 
1223 /// Determine the encoding to use for the given string name and length.
1224 static StringEncoding getStringEncoding(StringRef Str) {
1225   bool isChar6 = true;
1226   for (char C : Str) {
1227     if (isChar6)
1228       isChar6 = BitCodeAbbrevOp::isChar6(C);
1229     if ((unsigned char)C & 128)
1230       // don't bother scanning the rest.
1231       return SE_Fixed8;
1232   }
1233   if (isChar6)
1234     return SE_Char6;
1235   return SE_Fixed7;
1236 }
1237 
1238 static_assert(sizeof(GlobalValue::SanitizerMetadata) <= sizeof(unsigned),
1239               "Sanitizer Metadata is too large for naive serialization.");
1240 static unsigned
1241 serializeSanitizerMetadata(const GlobalValue::SanitizerMetadata &Meta) {
1242   return Meta.NoAddress | (Meta.NoHWAddress << 1) |
1243          (Meta.Memtag << 2) | (Meta.IsDynInit << 3);
1244 }
1245 
1246 /// Emit top-level description of module, including target triple, inline asm,
1247 /// descriptors for global variables, and function prototype info.
1248 /// Returns the bit offset to backpatch with the location of the real VST.
1249 void ModuleBitcodeWriter::writeModuleInfo() {
1250   // Emit various pieces of data attached to a module.
1251   if (!M.getTargetTriple().empty())
1252     writeStringRecord(Stream, bitc::MODULE_CODE_TRIPLE, M.getTargetTriple(),
1253                       0 /*TODO*/);
1254   const std::string &DL = M.getDataLayoutStr();
1255   if (!DL.empty())
1256     writeStringRecord(Stream, bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/);
1257   if (!M.getModuleInlineAsm().empty())
1258     writeStringRecord(Stream, bitc::MODULE_CODE_ASM, M.getModuleInlineAsm(),
1259                       0 /*TODO*/);
1260 
1261   // Emit information about sections and GC, computing how many there are. Also
1262   // compute the maximum alignment value.
1263   std::map<std::string, unsigned> SectionMap;
1264   std::map<std::string, unsigned> GCMap;
1265   MaybeAlign MaxAlignment;
1266   unsigned MaxGlobalType = 0;
1267   const auto UpdateMaxAlignment = [&MaxAlignment](const MaybeAlign A) {
1268     if (A)
1269       MaxAlignment = !MaxAlignment ? *A : std::max(*MaxAlignment, *A);
1270   };
1271   for (const GlobalVariable &GV : M.globals()) {
1272     UpdateMaxAlignment(GV.getAlign());
1273     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getValueType()));
1274     if (GV.hasSection()) {
1275       // Give section names unique ID's.
1276       unsigned &Entry = SectionMap[std::string(GV.getSection())];
1277       if (!Entry) {
1278         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
1279                           0 /*TODO*/);
1280         Entry = SectionMap.size();
1281       }
1282     }
1283   }
1284   for (const Function &F : M) {
1285     UpdateMaxAlignment(F.getAlign());
1286     if (F.hasSection()) {
1287       // Give section names unique ID's.
1288       unsigned &Entry = SectionMap[std::string(F.getSection())];
1289       if (!Entry) {
1290         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
1291                           0 /*TODO*/);
1292         Entry = SectionMap.size();
1293       }
1294     }
1295     if (F.hasGC()) {
1296       // Same for GC names.
1297       unsigned &Entry = GCMap[F.getGC()];
1298       if (!Entry) {
1299         writeStringRecord(Stream, bitc::MODULE_CODE_GCNAME, F.getGC(),
1300                           0 /*TODO*/);
1301         Entry = GCMap.size();
1302       }
1303     }
1304   }
1305 
1306   // Emit abbrev for globals, now that we know # sections and max alignment.
1307   unsigned SimpleGVarAbbrev = 0;
1308   if (!M.global_empty()) {
1309     // Add an abbrev for common globals with no visibility or thread localness.
1310     auto Abbv = std::make_shared<BitCodeAbbrev>();
1311     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
1312     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1313     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1314     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1315                               Log2_32_Ceil(MaxGlobalType+1)));
1316     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddrSpace << 2
1317                                                            //| explicitType << 1
1318                                                            //| constant
1319     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Initializer.
1320     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // Linkage.
1321     if (!MaxAlignment)                                     // Alignment.
1322       Abbv->Add(BitCodeAbbrevOp(0));
1323     else {
1324       unsigned MaxEncAlignment = getEncodedAlign(MaxAlignment);
1325       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1326                                Log2_32_Ceil(MaxEncAlignment+1)));
1327     }
1328     if (SectionMap.empty())                                    // Section.
1329       Abbv->Add(BitCodeAbbrevOp(0));
1330     else
1331       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1332                                Log2_32_Ceil(SectionMap.size()+1)));
1333     // Don't bother emitting vis + thread local.
1334     SimpleGVarAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1335   }
1336 
1337   SmallVector<unsigned, 64> Vals;
1338   // Emit the module's source file name.
1339   {
1340     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
1341     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
1342     if (Bits == SE_Char6)
1343       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
1344     else if (Bits == SE_Fixed7)
1345       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
1346 
1347     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
1348     auto Abbv = std::make_shared<BitCodeAbbrev>();
1349     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
1350     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1351     Abbv->Add(AbbrevOpToUse);
1352     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1353 
1354     for (const auto P : M.getSourceFileName())
1355       Vals.push_back((unsigned char)P);
1356 
1357     // Emit the finished record.
1358     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
1359     Vals.clear();
1360   }
1361 
1362   // Emit the global variable information.
1363   for (const GlobalVariable &GV : M.globals()) {
1364     unsigned AbbrevToUse = 0;
1365 
1366     // GLOBALVAR: [strtab offset, strtab size, type, isconst, initid,
1367     //             linkage, alignment, section, visibility, threadlocal,
1368     //             unnamed_addr, externally_initialized, dllstorageclass,
1369     //             comdat, attributes, DSO_Local, GlobalSanitizer]
1370     Vals.push_back(addToStrtab(GV.getName()));
1371     Vals.push_back(GV.getName().size());
1372     Vals.push_back(VE.getTypeID(GV.getValueType()));
1373     Vals.push_back(GV.getType()->getAddressSpace() << 2 | 2 | GV.isConstant());
1374     Vals.push_back(GV.isDeclaration() ? 0 :
1375                    (VE.getValueID(GV.getInitializer()) + 1));
1376     Vals.push_back(getEncodedLinkage(GV));
1377     Vals.push_back(getEncodedAlign(GV.getAlign()));
1378     Vals.push_back(GV.hasSection() ? SectionMap[std::string(GV.getSection())]
1379                                    : 0);
1380     if (GV.isThreadLocal() ||
1381         GV.getVisibility() != GlobalValue::DefaultVisibility ||
1382         GV.getUnnamedAddr() != GlobalValue::UnnamedAddr::None ||
1383         GV.isExternallyInitialized() ||
1384         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
1385         GV.hasComdat() || GV.hasAttributes() || GV.isDSOLocal() ||
1386         GV.hasPartition() || GV.hasSanitizerMetadata()) {
1387       Vals.push_back(getEncodedVisibility(GV));
1388       Vals.push_back(getEncodedThreadLocalMode(GV));
1389       Vals.push_back(getEncodedUnnamedAddr(GV));
1390       Vals.push_back(GV.isExternallyInitialized());
1391       Vals.push_back(getEncodedDLLStorageClass(GV));
1392       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
1393 
1394       auto AL = GV.getAttributesAsList(AttributeList::FunctionIndex);
1395       Vals.push_back(VE.getAttributeListID(AL));
1396 
1397       Vals.push_back(GV.isDSOLocal());
1398       Vals.push_back(addToStrtab(GV.getPartition()));
1399       Vals.push_back(GV.getPartition().size());
1400 
1401       Vals.push_back((GV.hasSanitizerMetadata() ? serializeSanitizerMetadata(
1402                                                       GV.getSanitizerMetadata())
1403                                                 : 0));
1404     } else {
1405       AbbrevToUse = SimpleGVarAbbrev;
1406     }
1407 
1408     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
1409     Vals.clear();
1410   }
1411 
1412   // Emit the function proto information.
1413   for (const Function &F : M) {
1414     // FUNCTION:  [strtab offset, strtab size, type, callingconv, isproto,
1415     //             linkage, paramattrs, alignment, section, visibility, gc,
1416     //             unnamed_addr, prologuedata, dllstorageclass, comdat,
1417     //             prefixdata, personalityfn, DSO_Local, addrspace]
1418     Vals.push_back(addToStrtab(F.getName()));
1419     Vals.push_back(F.getName().size());
1420     Vals.push_back(VE.getTypeID(F.getFunctionType()));
1421     Vals.push_back(F.getCallingConv());
1422     Vals.push_back(F.isDeclaration());
1423     Vals.push_back(getEncodedLinkage(F));
1424     Vals.push_back(VE.getAttributeListID(F.getAttributes()));
1425     Vals.push_back(getEncodedAlign(F.getAlign()));
1426     Vals.push_back(F.hasSection() ? SectionMap[std::string(F.getSection())]
1427                                   : 0);
1428     Vals.push_back(getEncodedVisibility(F));
1429     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
1430     Vals.push_back(getEncodedUnnamedAddr(F));
1431     Vals.push_back(F.hasPrologueData() ? (VE.getValueID(F.getPrologueData()) + 1)
1432                                        : 0);
1433     Vals.push_back(getEncodedDLLStorageClass(F));
1434     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
1435     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
1436                                      : 0);
1437     Vals.push_back(
1438         F.hasPersonalityFn() ? (VE.getValueID(F.getPersonalityFn()) + 1) : 0);
1439 
1440     Vals.push_back(F.isDSOLocal());
1441     Vals.push_back(F.getAddressSpace());
1442     Vals.push_back(addToStrtab(F.getPartition()));
1443     Vals.push_back(F.getPartition().size());
1444 
1445     unsigned AbbrevToUse = 0;
1446     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
1447     Vals.clear();
1448   }
1449 
1450   // Emit the alias information.
1451   for (const GlobalAlias &A : M.aliases()) {
1452     // ALIAS: [strtab offset, strtab size, alias type, aliasee val#, linkage,
1453     //         visibility, dllstorageclass, threadlocal, unnamed_addr,
1454     //         DSO_Local]
1455     Vals.push_back(addToStrtab(A.getName()));
1456     Vals.push_back(A.getName().size());
1457     Vals.push_back(VE.getTypeID(A.getValueType()));
1458     Vals.push_back(A.getType()->getAddressSpace());
1459     Vals.push_back(VE.getValueID(A.getAliasee()));
1460     Vals.push_back(getEncodedLinkage(A));
1461     Vals.push_back(getEncodedVisibility(A));
1462     Vals.push_back(getEncodedDLLStorageClass(A));
1463     Vals.push_back(getEncodedThreadLocalMode(A));
1464     Vals.push_back(getEncodedUnnamedAddr(A));
1465     Vals.push_back(A.isDSOLocal());
1466     Vals.push_back(addToStrtab(A.getPartition()));
1467     Vals.push_back(A.getPartition().size());
1468 
1469     unsigned AbbrevToUse = 0;
1470     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
1471     Vals.clear();
1472   }
1473 
1474   // Emit the ifunc information.
1475   for (const GlobalIFunc &I : M.ifuncs()) {
1476     // IFUNC: [strtab offset, strtab size, ifunc type, address space, resolver
1477     //         val#, linkage, visibility, DSO_Local]
1478     Vals.push_back(addToStrtab(I.getName()));
1479     Vals.push_back(I.getName().size());
1480     Vals.push_back(VE.getTypeID(I.getValueType()));
1481     Vals.push_back(I.getType()->getAddressSpace());
1482     Vals.push_back(VE.getValueID(I.getResolver()));
1483     Vals.push_back(getEncodedLinkage(I));
1484     Vals.push_back(getEncodedVisibility(I));
1485     Vals.push_back(I.isDSOLocal());
1486     Vals.push_back(addToStrtab(I.getPartition()));
1487     Vals.push_back(I.getPartition().size());
1488     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
1489     Vals.clear();
1490   }
1491 
1492   writeValueSymbolTableForwardDecl();
1493 }
1494 
1495 static uint64_t getOptimizationFlags(const Value *V) {
1496   uint64_t Flags = 0;
1497 
1498   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
1499     if (OBO->hasNoSignedWrap())
1500       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
1501     if (OBO->hasNoUnsignedWrap())
1502       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
1503   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
1504     if (PEO->isExact())
1505       Flags |= 1 << bitc::PEO_EXACT;
1506   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
1507     if (FPMO->hasAllowReassoc())
1508       Flags |= bitc::AllowReassoc;
1509     if (FPMO->hasNoNaNs())
1510       Flags |= bitc::NoNaNs;
1511     if (FPMO->hasNoInfs())
1512       Flags |= bitc::NoInfs;
1513     if (FPMO->hasNoSignedZeros())
1514       Flags |= bitc::NoSignedZeros;
1515     if (FPMO->hasAllowReciprocal())
1516       Flags |= bitc::AllowReciprocal;
1517     if (FPMO->hasAllowContract())
1518       Flags |= bitc::AllowContract;
1519     if (FPMO->hasApproxFunc())
1520       Flags |= bitc::ApproxFunc;
1521   }
1522 
1523   return Flags;
1524 }
1525 
1526 void ModuleBitcodeWriter::writeValueAsMetadata(
1527     const ValueAsMetadata *MD, SmallVectorImpl<uint64_t> &Record) {
1528   // Mimic an MDNode with a value as one operand.
1529   Value *V = MD->getValue();
1530   Record.push_back(VE.getTypeID(V->getType()));
1531   Record.push_back(VE.getValueID(V));
1532   Stream.EmitRecord(bitc::METADATA_VALUE, Record, 0);
1533   Record.clear();
1534 }
1535 
1536 void ModuleBitcodeWriter::writeMDTuple(const MDTuple *N,
1537                                        SmallVectorImpl<uint64_t> &Record,
1538                                        unsigned Abbrev) {
1539   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
1540     Metadata *MD = N->getOperand(i);
1541     assert(!(MD && isa<LocalAsMetadata>(MD)) &&
1542            "Unexpected function-local metadata");
1543     Record.push_back(VE.getMetadataOrNullID(MD));
1544   }
1545   Stream.EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
1546                                     : bitc::METADATA_NODE,
1547                     Record, Abbrev);
1548   Record.clear();
1549 }
1550 
1551 unsigned ModuleBitcodeWriter::createDILocationAbbrev() {
1552   // Assume the column is usually under 128, and always output the inlined-at
1553   // location (it's never more expensive than building an array size 1).
1554   auto Abbv = std::make_shared<BitCodeAbbrev>();
1555   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
1556   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1557   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1558   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1559   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1560   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1561   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1562   return Stream.EmitAbbrev(std::move(Abbv));
1563 }
1564 
1565 void ModuleBitcodeWriter::writeDILocation(const DILocation *N,
1566                                           SmallVectorImpl<uint64_t> &Record,
1567                                           unsigned &Abbrev) {
1568   if (!Abbrev)
1569     Abbrev = createDILocationAbbrev();
1570 
1571   Record.push_back(N->isDistinct());
1572   Record.push_back(N->getLine());
1573   Record.push_back(N->getColumn());
1574   Record.push_back(VE.getMetadataID(N->getScope()));
1575   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
1576   Record.push_back(N->isImplicitCode());
1577 
1578   Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
1579   Record.clear();
1580 }
1581 
1582 unsigned ModuleBitcodeWriter::createGenericDINodeAbbrev() {
1583   // Assume the column is usually under 128, and always output the inlined-at
1584   // location (it's never more expensive than building an array size 1).
1585   auto Abbv = std::make_shared<BitCodeAbbrev>();
1586   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
1587   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1588   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1589   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1590   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1591   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1592   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1593   return Stream.EmitAbbrev(std::move(Abbv));
1594 }
1595 
1596 void ModuleBitcodeWriter::writeGenericDINode(const GenericDINode *N,
1597                                              SmallVectorImpl<uint64_t> &Record,
1598                                              unsigned &Abbrev) {
1599   if (!Abbrev)
1600     Abbrev = createGenericDINodeAbbrev();
1601 
1602   Record.push_back(N->isDistinct());
1603   Record.push_back(N->getTag());
1604   Record.push_back(0); // Per-tag version field; unused for now.
1605 
1606   for (auto &I : N->operands())
1607     Record.push_back(VE.getMetadataOrNullID(I));
1608 
1609   Stream.EmitRecord(bitc::METADATA_GENERIC_DEBUG, Record, Abbrev);
1610   Record.clear();
1611 }
1612 
1613 void ModuleBitcodeWriter::writeDISubrange(const DISubrange *N,
1614                                           SmallVectorImpl<uint64_t> &Record,
1615                                           unsigned Abbrev) {
1616   const uint64_t Version = 2 << 1;
1617   Record.push_back((uint64_t)N->isDistinct() | Version);
1618   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1619   Record.push_back(VE.getMetadataOrNullID(N->getRawLowerBound()));
1620   Record.push_back(VE.getMetadataOrNullID(N->getRawUpperBound()));
1621   Record.push_back(VE.getMetadataOrNullID(N->getRawStride()));
1622 
1623   Stream.EmitRecord(bitc::METADATA_SUBRANGE, Record, Abbrev);
1624   Record.clear();
1625 }
1626 
1627 void ModuleBitcodeWriter::writeDIGenericSubrange(
1628     const DIGenericSubrange *N, SmallVectorImpl<uint64_t> &Record,
1629     unsigned Abbrev) {
1630   Record.push_back((uint64_t)N->isDistinct());
1631   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1632   Record.push_back(VE.getMetadataOrNullID(N->getRawLowerBound()));
1633   Record.push_back(VE.getMetadataOrNullID(N->getRawUpperBound()));
1634   Record.push_back(VE.getMetadataOrNullID(N->getRawStride()));
1635 
1636   Stream.EmitRecord(bitc::METADATA_GENERIC_SUBRANGE, Record, Abbrev);
1637   Record.clear();
1638 }
1639 
1640 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
1641   if ((int64_t)V >= 0)
1642     Vals.push_back(V << 1);
1643   else
1644     Vals.push_back((-V << 1) | 1);
1645 }
1646 
1647 static void emitWideAPInt(SmallVectorImpl<uint64_t> &Vals, const APInt &A) {
1648   // We have an arbitrary precision integer value to write whose
1649   // bit width is > 64. However, in canonical unsigned integer
1650   // format it is likely that the high bits are going to be zero.
1651   // So, we only write the number of active words.
1652   unsigned NumWords = A.getActiveWords();
1653   const uint64_t *RawData = A.getRawData();
1654   for (unsigned i = 0; i < NumWords; i++)
1655     emitSignedInt64(Vals, RawData[i]);
1656 }
1657 
1658 void ModuleBitcodeWriter::writeDIEnumerator(const DIEnumerator *N,
1659                                             SmallVectorImpl<uint64_t> &Record,
1660                                             unsigned Abbrev) {
1661   const uint64_t IsBigInt = 1 << 2;
1662   Record.push_back(IsBigInt | (N->isUnsigned() << 1) | N->isDistinct());
1663   Record.push_back(N->getValue().getBitWidth());
1664   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1665   emitWideAPInt(Record, N->getValue());
1666 
1667   Stream.EmitRecord(bitc::METADATA_ENUMERATOR, Record, Abbrev);
1668   Record.clear();
1669 }
1670 
1671 void ModuleBitcodeWriter::writeDIBasicType(const DIBasicType *N,
1672                                            SmallVectorImpl<uint64_t> &Record,
1673                                            unsigned Abbrev) {
1674   Record.push_back(N->isDistinct());
1675   Record.push_back(N->getTag());
1676   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1677   Record.push_back(N->getSizeInBits());
1678   Record.push_back(N->getAlignInBits());
1679   Record.push_back(N->getEncoding());
1680   Record.push_back(N->getFlags());
1681 
1682   Stream.EmitRecord(bitc::METADATA_BASIC_TYPE, Record, Abbrev);
1683   Record.clear();
1684 }
1685 
1686 void ModuleBitcodeWriter::writeDIStringType(const DIStringType *N,
1687                                             SmallVectorImpl<uint64_t> &Record,
1688                                             unsigned Abbrev) {
1689   Record.push_back(N->isDistinct());
1690   Record.push_back(N->getTag());
1691   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1692   Record.push_back(VE.getMetadataOrNullID(N->getStringLength()));
1693   Record.push_back(VE.getMetadataOrNullID(N->getStringLengthExp()));
1694   Record.push_back(VE.getMetadataOrNullID(N->getStringLocationExp()));
1695   Record.push_back(N->getSizeInBits());
1696   Record.push_back(N->getAlignInBits());
1697   Record.push_back(N->getEncoding());
1698 
1699   Stream.EmitRecord(bitc::METADATA_STRING_TYPE, Record, Abbrev);
1700   Record.clear();
1701 }
1702 
1703 void ModuleBitcodeWriter::writeDIDerivedType(const DIDerivedType *N,
1704                                              SmallVectorImpl<uint64_t> &Record,
1705                                              unsigned Abbrev) {
1706   Record.push_back(N->isDistinct());
1707   Record.push_back(N->getTag());
1708   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1709   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1710   Record.push_back(N->getLine());
1711   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1712   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1713   Record.push_back(N->getSizeInBits());
1714   Record.push_back(N->getAlignInBits());
1715   Record.push_back(N->getOffsetInBits());
1716   Record.push_back(N->getFlags());
1717   Record.push_back(VE.getMetadataOrNullID(N->getExtraData()));
1718 
1719   // DWARF address space is encoded as N->getDWARFAddressSpace() + 1. 0 means
1720   // that there is no DWARF address space associated with DIDerivedType.
1721   if (const auto &DWARFAddressSpace = N->getDWARFAddressSpace())
1722     Record.push_back(*DWARFAddressSpace + 1);
1723   else
1724     Record.push_back(0);
1725 
1726   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1727 
1728   Stream.EmitRecord(bitc::METADATA_DERIVED_TYPE, Record, Abbrev);
1729   Record.clear();
1730 }
1731 
1732 void ModuleBitcodeWriter::writeDICompositeType(
1733     const DICompositeType *N, SmallVectorImpl<uint64_t> &Record,
1734     unsigned Abbrev) {
1735   const unsigned IsNotUsedInOldTypeRef = 0x2;
1736   Record.push_back(IsNotUsedInOldTypeRef | (unsigned)N->isDistinct());
1737   Record.push_back(N->getTag());
1738   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1739   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1740   Record.push_back(N->getLine());
1741   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1742   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1743   Record.push_back(N->getSizeInBits());
1744   Record.push_back(N->getAlignInBits());
1745   Record.push_back(N->getOffsetInBits());
1746   Record.push_back(N->getFlags());
1747   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1748   Record.push_back(N->getRuntimeLang());
1749   Record.push_back(VE.getMetadataOrNullID(N->getVTableHolder()));
1750   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1751   Record.push_back(VE.getMetadataOrNullID(N->getRawIdentifier()));
1752   Record.push_back(VE.getMetadataOrNullID(N->getDiscriminator()));
1753   Record.push_back(VE.getMetadataOrNullID(N->getRawDataLocation()));
1754   Record.push_back(VE.getMetadataOrNullID(N->getRawAssociated()));
1755   Record.push_back(VE.getMetadataOrNullID(N->getRawAllocated()));
1756   Record.push_back(VE.getMetadataOrNullID(N->getRawRank()));
1757   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1758 
1759   Stream.EmitRecord(bitc::METADATA_COMPOSITE_TYPE, Record, Abbrev);
1760   Record.clear();
1761 }
1762 
1763 void ModuleBitcodeWriter::writeDISubroutineType(
1764     const DISubroutineType *N, SmallVectorImpl<uint64_t> &Record,
1765     unsigned Abbrev) {
1766   const unsigned HasNoOldTypeRefs = 0x2;
1767   Record.push_back(HasNoOldTypeRefs | (unsigned)N->isDistinct());
1768   Record.push_back(N->getFlags());
1769   Record.push_back(VE.getMetadataOrNullID(N->getTypeArray().get()));
1770   Record.push_back(N->getCC());
1771 
1772   Stream.EmitRecord(bitc::METADATA_SUBROUTINE_TYPE, Record, Abbrev);
1773   Record.clear();
1774 }
1775 
1776 void ModuleBitcodeWriter::writeDIFile(const DIFile *N,
1777                                       SmallVectorImpl<uint64_t> &Record,
1778                                       unsigned Abbrev) {
1779   Record.push_back(N->isDistinct());
1780   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
1781   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
1782   if (N->getRawChecksum()) {
1783     Record.push_back(N->getRawChecksum()->Kind);
1784     Record.push_back(VE.getMetadataOrNullID(N->getRawChecksum()->Value));
1785   } else {
1786     // Maintain backwards compatibility with the old internal representation of
1787     // CSK_None in ChecksumKind by writing nulls here when Checksum is None.
1788     Record.push_back(0);
1789     Record.push_back(VE.getMetadataOrNullID(nullptr));
1790   }
1791   auto Source = N->getRawSource();
1792   if (Source)
1793     Record.push_back(VE.getMetadataOrNullID(*Source));
1794 
1795   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
1796   Record.clear();
1797 }
1798 
1799 void ModuleBitcodeWriter::writeDICompileUnit(const DICompileUnit *N,
1800                                              SmallVectorImpl<uint64_t> &Record,
1801                                              unsigned Abbrev) {
1802   assert(N->isDistinct() && "Expected distinct compile units");
1803   Record.push_back(/* IsDistinct */ true);
1804   Record.push_back(N->getSourceLanguage());
1805   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1806   Record.push_back(VE.getMetadataOrNullID(N->getRawProducer()));
1807   Record.push_back(N->isOptimized());
1808   Record.push_back(VE.getMetadataOrNullID(N->getRawFlags()));
1809   Record.push_back(N->getRuntimeVersion());
1810   Record.push_back(VE.getMetadataOrNullID(N->getRawSplitDebugFilename()));
1811   Record.push_back(N->getEmissionKind());
1812   Record.push_back(VE.getMetadataOrNullID(N->getEnumTypes().get()));
1813   Record.push_back(VE.getMetadataOrNullID(N->getRetainedTypes().get()));
1814   Record.push_back(/* subprograms */ 0);
1815   Record.push_back(VE.getMetadataOrNullID(N->getGlobalVariables().get()));
1816   Record.push_back(VE.getMetadataOrNullID(N->getImportedEntities().get()));
1817   Record.push_back(N->getDWOId());
1818   Record.push_back(VE.getMetadataOrNullID(N->getMacros().get()));
1819   Record.push_back(N->getSplitDebugInlining());
1820   Record.push_back(N->getDebugInfoForProfiling());
1821   Record.push_back((unsigned)N->getNameTableKind());
1822   Record.push_back(N->getRangesBaseAddress());
1823   Record.push_back(VE.getMetadataOrNullID(N->getRawSysRoot()));
1824   Record.push_back(VE.getMetadataOrNullID(N->getRawSDK()));
1825 
1826   Stream.EmitRecord(bitc::METADATA_COMPILE_UNIT, Record, Abbrev);
1827   Record.clear();
1828 }
1829 
1830 void ModuleBitcodeWriter::writeDISubprogram(const DISubprogram *N,
1831                                             SmallVectorImpl<uint64_t> &Record,
1832                                             unsigned Abbrev) {
1833   const uint64_t HasUnitFlag = 1 << 1;
1834   const uint64_t HasSPFlagsFlag = 1 << 2;
1835   Record.push_back(uint64_t(N->isDistinct()) | HasUnitFlag | HasSPFlagsFlag);
1836   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1837   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1838   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1839   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1840   Record.push_back(N->getLine());
1841   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1842   Record.push_back(N->getScopeLine());
1843   Record.push_back(VE.getMetadataOrNullID(N->getContainingType()));
1844   Record.push_back(N->getSPFlags());
1845   Record.push_back(N->getVirtualIndex());
1846   Record.push_back(N->getFlags());
1847   Record.push_back(VE.getMetadataOrNullID(N->getRawUnit()));
1848   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1849   Record.push_back(VE.getMetadataOrNullID(N->getDeclaration()));
1850   Record.push_back(VE.getMetadataOrNullID(N->getRetainedNodes().get()));
1851   Record.push_back(N->getThisAdjustment());
1852   Record.push_back(VE.getMetadataOrNullID(N->getThrownTypes().get()));
1853   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1854   Record.push_back(VE.getMetadataOrNullID(N->getRawTargetFuncName()));
1855 
1856   Stream.EmitRecord(bitc::METADATA_SUBPROGRAM, Record, Abbrev);
1857   Record.clear();
1858 }
1859 
1860 void ModuleBitcodeWriter::writeDILexicalBlock(const DILexicalBlock *N,
1861                                               SmallVectorImpl<uint64_t> &Record,
1862                                               unsigned Abbrev) {
1863   Record.push_back(N->isDistinct());
1864   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1865   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1866   Record.push_back(N->getLine());
1867   Record.push_back(N->getColumn());
1868 
1869   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK, Record, Abbrev);
1870   Record.clear();
1871 }
1872 
1873 void ModuleBitcodeWriter::writeDILexicalBlockFile(
1874     const DILexicalBlockFile *N, SmallVectorImpl<uint64_t> &Record,
1875     unsigned Abbrev) {
1876   Record.push_back(N->isDistinct());
1877   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1878   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1879   Record.push_back(N->getDiscriminator());
1880 
1881   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK_FILE, Record, Abbrev);
1882   Record.clear();
1883 }
1884 
1885 void ModuleBitcodeWriter::writeDICommonBlock(const DICommonBlock *N,
1886                                              SmallVectorImpl<uint64_t> &Record,
1887                                              unsigned Abbrev) {
1888   Record.push_back(N->isDistinct());
1889   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1890   Record.push_back(VE.getMetadataOrNullID(N->getDecl()));
1891   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1892   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1893   Record.push_back(N->getLineNo());
1894 
1895   Stream.EmitRecord(bitc::METADATA_COMMON_BLOCK, Record, Abbrev);
1896   Record.clear();
1897 }
1898 
1899 void ModuleBitcodeWriter::writeDINamespace(const DINamespace *N,
1900                                            SmallVectorImpl<uint64_t> &Record,
1901                                            unsigned Abbrev) {
1902   Record.push_back(N->isDistinct() | N->getExportSymbols() << 1);
1903   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1904   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1905 
1906   Stream.EmitRecord(bitc::METADATA_NAMESPACE, Record, Abbrev);
1907   Record.clear();
1908 }
1909 
1910 void ModuleBitcodeWriter::writeDIMacro(const DIMacro *N,
1911                                        SmallVectorImpl<uint64_t> &Record,
1912                                        unsigned Abbrev) {
1913   Record.push_back(N->isDistinct());
1914   Record.push_back(N->getMacinfoType());
1915   Record.push_back(N->getLine());
1916   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1917   Record.push_back(VE.getMetadataOrNullID(N->getRawValue()));
1918 
1919   Stream.EmitRecord(bitc::METADATA_MACRO, Record, Abbrev);
1920   Record.clear();
1921 }
1922 
1923 void ModuleBitcodeWriter::writeDIMacroFile(const DIMacroFile *N,
1924                                            SmallVectorImpl<uint64_t> &Record,
1925                                            unsigned Abbrev) {
1926   Record.push_back(N->isDistinct());
1927   Record.push_back(N->getMacinfoType());
1928   Record.push_back(N->getLine());
1929   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1930   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1931 
1932   Stream.EmitRecord(bitc::METADATA_MACRO_FILE, Record, Abbrev);
1933   Record.clear();
1934 }
1935 
1936 void ModuleBitcodeWriter::writeDIArgList(const DIArgList *N,
1937                                          SmallVectorImpl<uint64_t> &Record,
1938                                          unsigned Abbrev) {
1939   Record.reserve(N->getArgs().size());
1940   for (ValueAsMetadata *MD : N->getArgs())
1941     Record.push_back(VE.getMetadataID(MD));
1942 
1943   Stream.EmitRecord(bitc::METADATA_ARG_LIST, Record, Abbrev);
1944   Record.clear();
1945 }
1946 
1947 void ModuleBitcodeWriter::writeDIModule(const DIModule *N,
1948                                         SmallVectorImpl<uint64_t> &Record,
1949                                         unsigned Abbrev) {
1950   Record.push_back(N->isDistinct());
1951   for (auto &I : N->operands())
1952     Record.push_back(VE.getMetadataOrNullID(I));
1953   Record.push_back(N->getLineNo());
1954   Record.push_back(N->getIsDecl());
1955 
1956   Stream.EmitRecord(bitc::METADATA_MODULE, Record, Abbrev);
1957   Record.clear();
1958 }
1959 
1960 void ModuleBitcodeWriter::writeDIAssignID(const DIAssignID *N,
1961                                           SmallVectorImpl<uint64_t> &Record,
1962                                           unsigned Abbrev) {
1963   // There are no arguments for this metadata type.
1964   Record.push_back(N->isDistinct());
1965   Stream.EmitRecord(bitc::METADATA_ASSIGN_ID, Record, Abbrev);
1966   Record.clear();
1967 }
1968 
1969 void ModuleBitcodeWriter::writeDITemplateTypeParameter(
1970     const DITemplateTypeParameter *N, SmallVectorImpl<uint64_t> &Record,
1971     unsigned Abbrev) {
1972   Record.push_back(N->isDistinct());
1973   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1974   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1975   Record.push_back(N->isDefault());
1976 
1977   Stream.EmitRecord(bitc::METADATA_TEMPLATE_TYPE, Record, Abbrev);
1978   Record.clear();
1979 }
1980 
1981 void ModuleBitcodeWriter::writeDITemplateValueParameter(
1982     const DITemplateValueParameter *N, SmallVectorImpl<uint64_t> &Record,
1983     unsigned Abbrev) {
1984   Record.push_back(N->isDistinct());
1985   Record.push_back(N->getTag());
1986   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1987   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1988   Record.push_back(N->isDefault());
1989   Record.push_back(VE.getMetadataOrNullID(N->getValue()));
1990 
1991   Stream.EmitRecord(bitc::METADATA_TEMPLATE_VALUE, Record, Abbrev);
1992   Record.clear();
1993 }
1994 
1995 void ModuleBitcodeWriter::writeDIGlobalVariable(
1996     const DIGlobalVariable *N, SmallVectorImpl<uint64_t> &Record,
1997     unsigned Abbrev) {
1998   const uint64_t Version = 2 << 1;
1999   Record.push_back((uint64_t)N->isDistinct() | Version);
2000   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2001   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2002   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
2003   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2004   Record.push_back(N->getLine());
2005   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2006   Record.push_back(N->isLocalToUnit());
2007   Record.push_back(N->isDefinition());
2008   Record.push_back(VE.getMetadataOrNullID(N->getStaticDataMemberDeclaration()));
2009   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams()));
2010   Record.push_back(N->getAlignInBits());
2011   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
2012 
2013   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR, Record, Abbrev);
2014   Record.clear();
2015 }
2016 
2017 void ModuleBitcodeWriter::writeDILocalVariable(
2018     const DILocalVariable *N, SmallVectorImpl<uint64_t> &Record,
2019     unsigned Abbrev) {
2020   // In order to support all possible bitcode formats in BitcodeReader we need
2021   // to distinguish the following cases:
2022   // 1) Record has no artificial tag (Record[1]),
2023   //   has no obsolete inlinedAt field (Record[9]).
2024   //   In this case Record size will be 8, HasAlignment flag is false.
2025   // 2) Record has artificial tag (Record[1]),
2026   //   has no obsolete inlignedAt field (Record[9]).
2027   //   In this case Record size will be 9, HasAlignment flag is false.
2028   // 3) Record has both artificial tag (Record[1]) and
2029   //   obsolete inlignedAt field (Record[9]).
2030   //   In this case Record size will be 10, HasAlignment flag is false.
2031   // 4) Record has neither artificial tag, nor inlignedAt field, but
2032   //   HasAlignment flag is true and Record[8] contains alignment value.
2033   const uint64_t HasAlignmentFlag = 1 << 1;
2034   Record.push_back((uint64_t)N->isDistinct() | HasAlignmentFlag);
2035   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2036   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2037   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2038   Record.push_back(N->getLine());
2039   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2040   Record.push_back(N->getArg());
2041   Record.push_back(N->getFlags());
2042   Record.push_back(N->getAlignInBits());
2043   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
2044 
2045   Stream.EmitRecord(bitc::METADATA_LOCAL_VAR, Record, Abbrev);
2046   Record.clear();
2047 }
2048 
2049 void ModuleBitcodeWriter::writeDILabel(
2050     const DILabel *N, SmallVectorImpl<uint64_t> &Record,
2051     unsigned Abbrev) {
2052   Record.push_back((uint64_t)N->isDistinct());
2053   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2054   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2055   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2056   Record.push_back(N->getLine());
2057 
2058   Stream.EmitRecord(bitc::METADATA_LABEL, Record, Abbrev);
2059   Record.clear();
2060 }
2061 
2062 void ModuleBitcodeWriter::writeDIExpression(const DIExpression *N,
2063                                             SmallVectorImpl<uint64_t> &Record,
2064                                             unsigned Abbrev) {
2065   Record.reserve(N->getElements().size() + 1);
2066   const uint64_t Version = 3 << 1;
2067   Record.push_back((uint64_t)N->isDistinct() | Version);
2068   Record.append(N->elements_begin(), N->elements_end());
2069 
2070   Stream.EmitRecord(bitc::METADATA_EXPRESSION, Record, Abbrev);
2071   Record.clear();
2072 }
2073 
2074 void ModuleBitcodeWriter::writeDIGlobalVariableExpression(
2075     const DIGlobalVariableExpression *N, SmallVectorImpl<uint64_t> &Record,
2076     unsigned Abbrev) {
2077   Record.push_back(N->isDistinct());
2078   Record.push_back(VE.getMetadataOrNullID(N->getVariable()));
2079   Record.push_back(VE.getMetadataOrNullID(N->getExpression()));
2080 
2081   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR_EXPR, Record, Abbrev);
2082   Record.clear();
2083 }
2084 
2085 void ModuleBitcodeWriter::writeDIObjCProperty(const DIObjCProperty *N,
2086                                               SmallVectorImpl<uint64_t> &Record,
2087                                               unsigned Abbrev) {
2088   Record.push_back(N->isDistinct());
2089   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2090   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2091   Record.push_back(N->getLine());
2092   Record.push_back(VE.getMetadataOrNullID(N->getRawSetterName()));
2093   Record.push_back(VE.getMetadataOrNullID(N->getRawGetterName()));
2094   Record.push_back(N->getAttributes());
2095   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2096 
2097   Stream.EmitRecord(bitc::METADATA_OBJC_PROPERTY, Record, Abbrev);
2098   Record.clear();
2099 }
2100 
2101 void ModuleBitcodeWriter::writeDIImportedEntity(
2102     const DIImportedEntity *N, SmallVectorImpl<uint64_t> &Record,
2103     unsigned Abbrev) {
2104   Record.push_back(N->isDistinct());
2105   Record.push_back(N->getTag());
2106   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2107   Record.push_back(VE.getMetadataOrNullID(N->getEntity()));
2108   Record.push_back(N->getLine());
2109   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2110   Record.push_back(VE.getMetadataOrNullID(N->getRawFile()));
2111   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
2112 
2113   Stream.EmitRecord(bitc::METADATA_IMPORTED_ENTITY, Record, Abbrev);
2114   Record.clear();
2115 }
2116 
2117 unsigned ModuleBitcodeWriter::createNamedMetadataAbbrev() {
2118   auto Abbv = std::make_shared<BitCodeAbbrev>();
2119   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
2120   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2121   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2122   return Stream.EmitAbbrev(std::move(Abbv));
2123 }
2124 
2125 void ModuleBitcodeWriter::writeNamedMetadata(
2126     SmallVectorImpl<uint64_t> &Record) {
2127   if (M.named_metadata_empty())
2128     return;
2129 
2130   unsigned Abbrev = createNamedMetadataAbbrev();
2131   for (const NamedMDNode &NMD : M.named_metadata()) {
2132     // Write name.
2133     StringRef Str = NMD.getName();
2134     Record.append(Str.bytes_begin(), Str.bytes_end());
2135     Stream.EmitRecord(bitc::METADATA_NAME, Record, Abbrev);
2136     Record.clear();
2137 
2138     // Write named metadata operands.
2139     for (const MDNode *N : NMD.operands())
2140       Record.push_back(VE.getMetadataID(N));
2141     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
2142     Record.clear();
2143   }
2144 }
2145 
2146 unsigned ModuleBitcodeWriter::createMetadataStringsAbbrev() {
2147   auto Abbv = std::make_shared<BitCodeAbbrev>();
2148   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRINGS));
2149   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // # of strings
2150   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // offset to chars
2151   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
2152   return Stream.EmitAbbrev(std::move(Abbv));
2153 }
2154 
2155 /// Write out a record for MDString.
2156 ///
2157 /// All the metadata strings in a metadata block are emitted in a single
2158 /// record.  The sizes and strings themselves are shoved into a blob.
2159 void ModuleBitcodeWriter::writeMetadataStrings(
2160     ArrayRef<const Metadata *> Strings, SmallVectorImpl<uint64_t> &Record) {
2161   if (Strings.empty())
2162     return;
2163 
2164   // Start the record with the number of strings.
2165   Record.push_back(bitc::METADATA_STRINGS);
2166   Record.push_back(Strings.size());
2167 
2168   // Emit the sizes of the strings in the blob.
2169   SmallString<256> Blob;
2170   {
2171     BitstreamWriter W(Blob);
2172     for (const Metadata *MD : Strings)
2173       W.EmitVBR(cast<MDString>(MD)->getLength(), 6);
2174     W.FlushToWord();
2175   }
2176 
2177   // Add the offset to the strings to the record.
2178   Record.push_back(Blob.size());
2179 
2180   // Add the strings to the blob.
2181   for (const Metadata *MD : Strings)
2182     Blob.append(cast<MDString>(MD)->getString());
2183 
2184   // Emit the final record.
2185   Stream.EmitRecordWithBlob(createMetadataStringsAbbrev(), Record, Blob);
2186   Record.clear();
2187 }
2188 
2189 // Generates an enum to use as an index in the Abbrev array of Metadata record.
2190 enum MetadataAbbrev : unsigned {
2191 #define HANDLE_MDNODE_LEAF(CLASS) CLASS##AbbrevID,
2192 #include "llvm/IR/Metadata.def"
2193   LastPlusOne
2194 };
2195 
2196 void ModuleBitcodeWriter::writeMetadataRecords(
2197     ArrayRef<const Metadata *> MDs, SmallVectorImpl<uint64_t> &Record,
2198     std::vector<unsigned> *MDAbbrevs, std::vector<uint64_t> *IndexPos) {
2199   if (MDs.empty())
2200     return;
2201 
2202   // Initialize MDNode abbreviations.
2203 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
2204 #include "llvm/IR/Metadata.def"
2205 
2206   for (const Metadata *MD : MDs) {
2207     if (IndexPos)
2208       IndexPos->push_back(Stream.GetCurrentBitNo());
2209     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
2210       assert(N->isResolved() && "Expected forward references to be resolved");
2211 
2212       switch (N->getMetadataID()) {
2213       default:
2214         llvm_unreachable("Invalid MDNode subclass");
2215 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
2216   case Metadata::CLASS##Kind:                                                  \
2217     if (MDAbbrevs)                                                             \
2218       write##CLASS(cast<CLASS>(N), Record,                                     \
2219                    (*MDAbbrevs)[MetadataAbbrev::CLASS##AbbrevID]);             \
2220     else                                                                       \
2221       write##CLASS(cast<CLASS>(N), Record, CLASS##Abbrev);                     \
2222     continue;
2223 #include "llvm/IR/Metadata.def"
2224       }
2225     }
2226     writeValueAsMetadata(cast<ValueAsMetadata>(MD), Record);
2227   }
2228 }
2229 
2230 void ModuleBitcodeWriter::writeModuleMetadata() {
2231   if (!VE.hasMDs() && M.named_metadata_empty())
2232     return;
2233 
2234   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 4);
2235   SmallVector<uint64_t, 64> Record;
2236 
2237   // Emit all abbrevs upfront, so that the reader can jump in the middle of the
2238   // block and load any metadata.
2239   std::vector<unsigned> MDAbbrevs;
2240 
2241   MDAbbrevs.resize(MetadataAbbrev::LastPlusOne);
2242   MDAbbrevs[MetadataAbbrev::DILocationAbbrevID] = createDILocationAbbrev();
2243   MDAbbrevs[MetadataAbbrev::GenericDINodeAbbrevID] =
2244       createGenericDINodeAbbrev();
2245 
2246   auto Abbv = std::make_shared<BitCodeAbbrev>();
2247   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX_OFFSET));
2248   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2249   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2250   unsigned OffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2251 
2252   Abbv = std::make_shared<BitCodeAbbrev>();
2253   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX));
2254   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2255   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2256   unsigned IndexAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2257 
2258   // Emit MDStrings together upfront.
2259   writeMetadataStrings(VE.getMDStrings(), Record);
2260 
2261   // We only emit an index for the metadata record if we have more than a given
2262   // (naive) threshold of metadatas, otherwise it is not worth it.
2263   if (VE.getNonMDStrings().size() > IndexThreshold) {
2264     // Write a placeholder value in for the offset of the metadata index,
2265     // which is written after the records, so that it can include
2266     // the offset of each entry. The placeholder offset will be
2267     // updated after all records are emitted.
2268     uint64_t Vals[] = {0, 0};
2269     Stream.EmitRecord(bitc::METADATA_INDEX_OFFSET, Vals, OffsetAbbrev);
2270   }
2271 
2272   // Compute and save the bit offset to the current position, which will be
2273   // patched when we emit the index later. We can simply subtract the 64-bit
2274   // fixed size from the current bit number to get the location to backpatch.
2275   uint64_t IndexOffsetRecordBitPos = Stream.GetCurrentBitNo();
2276 
2277   // This index will contain the bitpos for each individual record.
2278   std::vector<uint64_t> IndexPos;
2279   IndexPos.reserve(VE.getNonMDStrings().size());
2280 
2281   // Write all the records
2282   writeMetadataRecords(VE.getNonMDStrings(), Record, &MDAbbrevs, &IndexPos);
2283 
2284   if (VE.getNonMDStrings().size() > IndexThreshold) {
2285     // Now that we have emitted all the records we will emit the index. But
2286     // first
2287     // backpatch the forward reference so that the reader can skip the records
2288     // efficiently.
2289     Stream.BackpatchWord64(IndexOffsetRecordBitPos - 64,
2290                            Stream.GetCurrentBitNo() - IndexOffsetRecordBitPos);
2291 
2292     // Delta encode the index.
2293     uint64_t PreviousValue = IndexOffsetRecordBitPos;
2294     for (auto &Elt : IndexPos) {
2295       auto EltDelta = Elt - PreviousValue;
2296       PreviousValue = Elt;
2297       Elt = EltDelta;
2298     }
2299     // Emit the index record.
2300     Stream.EmitRecord(bitc::METADATA_INDEX, IndexPos, IndexAbbrev);
2301     IndexPos.clear();
2302   }
2303 
2304   // Write the named metadata now.
2305   writeNamedMetadata(Record);
2306 
2307   auto AddDeclAttachedMetadata = [&](const GlobalObject &GO) {
2308     SmallVector<uint64_t, 4> Record;
2309     Record.push_back(VE.getValueID(&GO));
2310     pushGlobalMetadataAttachment(Record, GO);
2311     Stream.EmitRecord(bitc::METADATA_GLOBAL_DECL_ATTACHMENT, Record);
2312   };
2313   for (const Function &F : M)
2314     if (F.isDeclaration() && F.hasMetadata())
2315       AddDeclAttachedMetadata(F);
2316   // FIXME: Only store metadata for declarations here, and move data for global
2317   // variable definitions to a separate block (PR28134).
2318   for (const GlobalVariable &GV : M.globals())
2319     if (GV.hasMetadata())
2320       AddDeclAttachedMetadata(GV);
2321 
2322   Stream.ExitBlock();
2323 }
2324 
2325 void ModuleBitcodeWriter::writeFunctionMetadata(const Function &F) {
2326   if (!VE.hasMDs())
2327     return;
2328 
2329   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
2330   SmallVector<uint64_t, 64> Record;
2331   writeMetadataStrings(VE.getMDStrings(), Record);
2332   writeMetadataRecords(VE.getNonMDStrings(), Record);
2333   Stream.ExitBlock();
2334 }
2335 
2336 void ModuleBitcodeWriter::pushGlobalMetadataAttachment(
2337     SmallVectorImpl<uint64_t> &Record, const GlobalObject &GO) {
2338   // [n x [id, mdnode]]
2339   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2340   GO.getAllMetadata(MDs);
2341   for (const auto &I : MDs) {
2342     Record.push_back(I.first);
2343     Record.push_back(VE.getMetadataID(I.second));
2344   }
2345 }
2346 
2347 void ModuleBitcodeWriter::writeFunctionMetadataAttachment(const Function &F) {
2348   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
2349 
2350   SmallVector<uint64_t, 64> Record;
2351 
2352   if (F.hasMetadata()) {
2353     pushGlobalMetadataAttachment(Record, F);
2354     Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2355     Record.clear();
2356   }
2357 
2358   // Write metadata attachments
2359   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
2360   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2361   for (const BasicBlock &BB : F)
2362     for (const Instruction &I : BB) {
2363       MDs.clear();
2364       I.getAllMetadataOtherThanDebugLoc(MDs);
2365 
2366       // If no metadata, ignore instruction.
2367       if (MDs.empty()) continue;
2368 
2369       Record.push_back(VE.getInstructionID(&I));
2370 
2371       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
2372         Record.push_back(MDs[i].first);
2373         Record.push_back(VE.getMetadataID(MDs[i].second));
2374       }
2375       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2376       Record.clear();
2377     }
2378 
2379   Stream.ExitBlock();
2380 }
2381 
2382 void ModuleBitcodeWriter::writeModuleMetadataKinds() {
2383   SmallVector<uint64_t, 64> Record;
2384 
2385   // Write metadata kinds
2386   // METADATA_KIND - [n x [id, name]]
2387   SmallVector<StringRef, 8> Names;
2388   M.getMDKindNames(Names);
2389 
2390   if (Names.empty()) return;
2391 
2392   Stream.EnterSubblock(bitc::METADATA_KIND_BLOCK_ID, 3);
2393 
2394   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
2395     Record.push_back(MDKindID);
2396     StringRef KName = Names[MDKindID];
2397     Record.append(KName.begin(), KName.end());
2398 
2399     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
2400     Record.clear();
2401   }
2402 
2403   Stream.ExitBlock();
2404 }
2405 
2406 void ModuleBitcodeWriter::writeOperandBundleTags() {
2407   // Write metadata kinds
2408   //
2409   // OPERAND_BUNDLE_TAGS_BLOCK_ID : N x OPERAND_BUNDLE_TAG
2410   //
2411   // OPERAND_BUNDLE_TAG - [strchr x N]
2412 
2413   SmallVector<StringRef, 8> Tags;
2414   M.getOperandBundleTags(Tags);
2415 
2416   if (Tags.empty())
2417     return;
2418 
2419   Stream.EnterSubblock(bitc::OPERAND_BUNDLE_TAGS_BLOCK_ID, 3);
2420 
2421   SmallVector<uint64_t, 64> Record;
2422 
2423   for (auto Tag : Tags) {
2424     Record.append(Tag.begin(), Tag.end());
2425 
2426     Stream.EmitRecord(bitc::OPERAND_BUNDLE_TAG, Record, 0);
2427     Record.clear();
2428   }
2429 
2430   Stream.ExitBlock();
2431 }
2432 
2433 void ModuleBitcodeWriter::writeSyncScopeNames() {
2434   SmallVector<StringRef, 8> SSNs;
2435   M.getContext().getSyncScopeNames(SSNs);
2436   if (SSNs.empty())
2437     return;
2438 
2439   Stream.EnterSubblock(bitc::SYNC_SCOPE_NAMES_BLOCK_ID, 2);
2440 
2441   SmallVector<uint64_t, 64> Record;
2442   for (auto SSN : SSNs) {
2443     Record.append(SSN.begin(), SSN.end());
2444     Stream.EmitRecord(bitc::SYNC_SCOPE_NAME, Record, 0);
2445     Record.clear();
2446   }
2447 
2448   Stream.ExitBlock();
2449 }
2450 
2451 void ModuleBitcodeWriter::writeConstants(unsigned FirstVal, unsigned LastVal,
2452                                          bool isGlobal) {
2453   if (FirstVal == LastVal) return;
2454 
2455   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
2456 
2457   unsigned AggregateAbbrev = 0;
2458   unsigned String8Abbrev = 0;
2459   unsigned CString7Abbrev = 0;
2460   unsigned CString6Abbrev = 0;
2461   // If this is a constant pool for the module, emit module-specific abbrevs.
2462   if (isGlobal) {
2463     // Abbrev for CST_CODE_AGGREGATE.
2464     auto Abbv = std::make_shared<BitCodeAbbrev>();
2465     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
2466     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2467     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
2468     AggregateAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2469 
2470     // Abbrev for CST_CODE_STRING.
2471     Abbv = std::make_shared<BitCodeAbbrev>();
2472     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
2473     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2474     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2475     String8Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2476     // Abbrev for CST_CODE_CSTRING.
2477     Abbv = std::make_shared<BitCodeAbbrev>();
2478     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2479     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2480     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2481     CString7Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2482     // Abbrev for CST_CODE_CSTRING.
2483     Abbv = std::make_shared<BitCodeAbbrev>();
2484     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2485     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2486     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2487     CString6Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2488   }
2489 
2490   SmallVector<uint64_t, 64> Record;
2491 
2492   const ValueEnumerator::ValueList &Vals = VE.getValues();
2493   Type *LastTy = nullptr;
2494   for (unsigned i = FirstVal; i != LastVal; ++i) {
2495     const Value *V = Vals[i].first;
2496     // If we need to switch types, do so now.
2497     if (V->getType() != LastTy) {
2498       LastTy = V->getType();
2499       Record.push_back(VE.getTypeID(LastTy));
2500       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
2501                         CONSTANTS_SETTYPE_ABBREV);
2502       Record.clear();
2503     }
2504 
2505     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
2506       Record.push_back(VE.getTypeID(IA->getFunctionType()));
2507       Record.push_back(
2508           unsigned(IA->hasSideEffects()) | unsigned(IA->isAlignStack()) << 1 |
2509           unsigned(IA->getDialect() & 1) << 2 | unsigned(IA->canThrow()) << 3);
2510 
2511       // Add the asm string.
2512       const std::string &AsmStr = IA->getAsmString();
2513       Record.push_back(AsmStr.size());
2514       Record.append(AsmStr.begin(), AsmStr.end());
2515 
2516       // Add the constraint string.
2517       const std::string &ConstraintStr = IA->getConstraintString();
2518       Record.push_back(ConstraintStr.size());
2519       Record.append(ConstraintStr.begin(), ConstraintStr.end());
2520       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
2521       Record.clear();
2522       continue;
2523     }
2524     const Constant *C = cast<Constant>(V);
2525     unsigned Code = -1U;
2526     unsigned AbbrevToUse = 0;
2527     if (C->isNullValue()) {
2528       Code = bitc::CST_CODE_NULL;
2529     } else if (isa<PoisonValue>(C)) {
2530       Code = bitc::CST_CODE_POISON;
2531     } else if (isa<UndefValue>(C)) {
2532       Code = bitc::CST_CODE_UNDEF;
2533     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
2534       if (IV->getBitWidth() <= 64) {
2535         uint64_t V = IV->getSExtValue();
2536         emitSignedInt64(Record, V);
2537         Code = bitc::CST_CODE_INTEGER;
2538         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
2539       } else {                             // Wide integers, > 64 bits in size.
2540         emitWideAPInt(Record, IV->getValue());
2541         Code = bitc::CST_CODE_WIDE_INTEGER;
2542       }
2543     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
2544       Code = bitc::CST_CODE_FLOAT;
2545       Type *Ty = CFP->getType();
2546       if (Ty->isHalfTy() || Ty->isBFloatTy() || Ty->isFloatTy() ||
2547           Ty->isDoubleTy()) {
2548         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
2549       } else if (Ty->isX86_FP80Ty()) {
2550         // api needed to prevent premature destruction
2551         // bits are not in the same order as a normal i80 APInt, compensate.
2552         APInt api = CFP->getValueAPF().bitcastToAPInt();
2553         const uint64_t *p = api.getRawData();
2554         Record.push_back((p[1] << 48) | (p[0] >> 16));
2555         Record.push_back(p[0] & 0xffffLL);
2556       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
2557         APInt api = CFP->getValueAPF().bitcastToAPInt();
2558         const uint64_t *p = api.getRawData();
2559         Record.push_back(p[0]);
2560         Record.push_back(p[1]);
2561       } else {
2562         assert(0 && "Unknown FP type!");
2563       }
2564     } else if (isa<ConstantDataSequential>(C) &&
2565                cast<ConstantDataSequential>(C)->isString()) {
2566       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
2567       // Emit constant strings specially.
2568       unsigned NumElts = Str->getNumElements();
2569       // If this is a null-terminated string, use the denser CSTRING encoding.
2570       if (Str->isCString()) {
2571         Code = bitc::CST_CODE_CSTRING;
2572         --NumElts;  // Don't encode the null, which isn't allowed by char6.
2573       } else {
2574         Code = bitc::CST_CODE_STRING;
2575         AbbrevToUse = String8Abbrev;
2576       }
2577       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
2578       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
2579       for (unsigned i = 0; i != NumElts; ++i) {
2580         unsigned char V = Str->getElementAsInteger(i);
2581         Record.push_back(V);
2582         isCStr7 &= (V & 128) == 0;
2583         if (isCStrChar6)
2584           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
2585       }
2586 
2587       if (isCStrChar6)
2588         AbbrevToUse = CString6Abbrev;
2589       else if (isCStr7)
2590         AbbrevToUse = CString7Abbrev;
2591     } else if (const ConstantDataSequential *CDS =
2592                   dyn_cast<ConstantDataSequential>(C)) {
2593       Code = bitc::CST_CODE_DATA;
2594       Type *EltTy = CDS->getElementType();
2595       if (isa<IntegerType>(EltTy)) {
2596         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2597           Record.push_back(CDS->getElementAsInteger(i));
2598       } else {
2599         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2600           Record.push_back(
2601               CDS->getElementAsAPFloat(i).bitcastToAPInt().getLimitedValue());
2602       }
2603     } else if (isa<ConstantAggregate>(C)) {
2604       Code = bitc::CST_CODE_AGGREGATE;
2605       for (const Value *Op : C->operands())
2606         Record.push_back(VE.getValueID(Op));
2607       AbbrevToUse = AggregateAbbrev;
2608     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
2609       switch (CE->getOpcode()) {
2610       default:
2611         if (Instruction::isCast(CE->getOpcode())) {
2612           Code = bitc::CST_CODE_CE_CAST;
2613           Record.push_back(getEncodedCastOpcode(CE->getOpcode()));
2614           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2615           Record.push_back(VE.getValueID(C->getOperand(0)));
2616           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
2617         } else {
2618           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
2619           Code = bitc::CST_CODE_CE_BINOP;
2620           Record.push_back(getEncodedBinaryOpcode(CE->getOpcode()));
2621           Record.push_back(VE.getValueID(C->getOperand(0)));
2622           Record.push_back(VE.getValueID(C->getOperand(1)));
2623           uint64_t Flags = getOptimizationFlags(CE);
2624           if (Flags != 0)
2625             Record.push_back(Flags);
2626         }
2627         break;
2628       case Instruction::FNeg: {
2629         assert(CE->getNumOperands() == 1 && "Unknown constant expr!");
2630         Code = bitc::CST_CODE_CE_UNOP;
2631         Record.push_back(getEncodedUnaryOpcode(CE->getOpcode()));
2632         Record.push_back(VE.getValueID(C->getOperand(0)));
2633         uint64_t Flags = getOptimizationFlags(CE);
2634         if (Flags != 0)
2635           Record.push_back(Flags);
2636         break;
2637       }
2638       case Instruction::GetElementPtr: {
2639         Code = bitc::CST_CODE_CE_GEP;
2640         const auto *GO = cast<GEPOperator>(C);
2641         Record.push_back(VE.getTypeID(GO->getSourceElementType()));
2642         if (Optional<unsigned> Idx = GO->getInRangeIndex()) {
2643           Code = bitc::CST_CODE_CE_GEP_WITH_INRANGE_INDEX;
2644           Record.push_back((*Idx << 1) | GO->isInBounds());
2645         } else if (GO->isInBounds())
2646           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
2647         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
2648           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
2649           Record.push_back(VE.getValueID(C->getOperand(i)));
2650         }
2651         break;
2652       }
2653       case Instruction::Select:
2654         Code = bitc::CST_CODE_CE_SELECT;
2655         Record.push_back(VE.getValueID(C->getOperand(0)));
2656         Record.push_back(VE.getValueID(C->getOperand(1)));
2657         Record.push_back(VE.getValueID(C->getOperand(2)));
2658         break;
2659       case Instruction::ExtractElement:
2660         Code = bitc::CST_CODE_CE_EXTRACTELT;
2661         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2662         Record.push_back(VE.getValueID(C->getOperand(0)));
2663         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
2664         Record.push_back(VE.getValueID(C->getOperand(1)));
2665         break;
2666       case Instruction::InsertElement:
2667         Code = bitc::CST_CODE_CE_INSERTELT;
2668         Record.push_back(VE.getValueID(C->getOperand(0)));
2669         Record.push_back(VE.getValueID(C->getOperand(1)));
2670         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
2671         Record.push_back(VE.getValueID(C->getOperand(2)));
2672         break;
2673       case Instruction::ShuffleVector:
2674         // If the return type and argument types are the same, this is a
2675         // standard shufflevector instruction.  If the types are different,
2676         // then the shuffle is widening or truncating the input vectors, and
2677         // the argument type must also be encoded.
2678         if (C->getType() == C->getOperand(0)->getType()) {
2679           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
2680         } else {
2681           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
2682           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2683         }
2684         Record.push_back(VE.getValueID(C->getOperand(0)));
2685         Record.push_back(VE.getValueID(C->getOperand(1)));
2686         Record.push_back(VE.getValueID(CE->getShuffleMaskForBitcode()));
2687         break;
2688       case Instruction::ICmp:
2689       case Instruction::FCmp:
2690         Code = bitc::CST_CODE_CE_CMP;
2691         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2692         Record.push_back(VE.getValueID(C->getOperand(0)));
2693         Record.push_back(VE.getValueID(C->getOperand(1)));
2694         Record.push_back(CE->getPredicate());
2695         break;
2696       }
2697     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
2698       Code = bitc::CST_CODE_BLOCKADDRESS;
2699       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
2700       Record.push_back(VE.getValueID(BA->getFunction()));
2701       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
2702     } else if (const auto *Equiv = dyn_cast<DSOLocalEquivalent>(C)) {
2703       Code = bitc::CST_CODE_DSO_LOCAL_EQUIVALENT;
2704       Record.push_back(VE.getTypeID(Equiv->getGlobalValue()->getType()));
2705       Record.push_back(VE.getValueID(Equiv->getGlobalValue()));
2706     } else if (const auto *NC = dyn_cast<NoCFIValue>(C)) {
2707       Code = bitc::CST_CODE_NO_CFI_VALUE;
2708       Record.push_back(VE.getTypeID(NC->getGlobalValue()->getType()));
2709       Record.push_back(VE.getValueID(NC->getGlobalValue()));
2710     } else {
2711 #ifndef NDEBUG
2712       C->dump();
2713 #endif
2714       llvm_unreachable("Unknown constant!");
2715     }
2716     Stream.EmitRecord(Code, Record, AbbrevToUse);
2717     Record.clear();
2718   }
2719 
2720   Stream.ExitBlock();
2721 }
2722 
2723 void ModuleBitcodeWriter::writeModuleConstants() {
2724   const ValueEnumerator::ValueList &Vals = VE.getValues();
2725 
2726   // Find the first constant to emit, which is the first non-globalvalue value.
2727   // We know globalvalues have been emitted by WriteModuleInfo.
2728   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
2729     if (!isa<GlobalValue>(Vals[i].first)) {
2730       writeConstants(i, Vals.size(), true);
2731       return;
2732     }
2733   }
2734 }
2735 
2736 /// pushValueAndType - The file has to encode both the value and type id for
2737 /// many values, because we need to know what type to create for forward
2738 /// references.  However, most operands are not forward references, so this type
2739 /// field is not needed.
2740 ///
2741 /// This function adds V's value ID to Vals.  If the value ID is higher than the
2742 /// instruction ID, then it is a forward reference, and it also includes the
2743 /// type ID.  The value ID that is written is encoded relative to the InstID.
2744 bool ModuleBitcodeWriter::pushValueAndType(const Value *V, unsigned InstID,
2745                                            SmallVectorImpl<unsigned> &Vals) {
2746   unsigned ValID = VE.getValueID(V);
2747   // Make encoding relative to the InstID.
2748   Vals.push_back(InstID - ValID);
2749   if (ValID >= InstID) {
2750     Vals.push_back(VE.getTypeID(V->getType()));
2751     return true;
2752   }
2753   return false;
2754 }
2755 
2756 void ModuleBitcodeWriter::writeOperandBundles(const CallBase &CS,
2757                                               unsigned InstID) {
2758   SmallVector<unsigned, 64> Record;
2759   LLVMContext &C = CS.getContext();
2760 
2761   for (unsigned i = 0, e = CS.getNumOperandBundles(); i != e; ++i) {
2762     const auto &Bundle = CS.getOperandBundleAt(i);
2763     Record.push_back(C.getOperandBundleTagID(Bundle.getTagName()));
2764 
2765     for (auto &Input : Bundle.Inputs)
2766       pushValueAndType(Input, InstID, Record);
2767 
2768     Stream.EmitRecord(bitc::FUNC_CODE_OPERAND_BUNDLE, Record);
2769     Record.clear();
2770   }
2771 }
2772 
2773 /// pushValue - Like pushValueAndType, but where the type of the value is
2774 /// omitted (perhaps it was already encoded in an earlier operand).
2775 void ModuleBitcodeWriter::pushValue(const Value *V, unsigned InstID,
2776                                     SmallVectorImpl<unsigned> &Vals) {
2777   unsigned ValID = VE.getValueID(V);
2778   Vals.push_back(InstID - ValID);
2779 }
2780 
2781 void ModuleBitcodeWriter::pushValueSigned(const Value *V, unsigned InstID,
2782                                           SmallVectorImpl<uint64_t> &Vals) {
2783   unsigned ValID = VE.getValueID(V);
2784   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
2785   emitSignedInt64(Vals, diff);
2786 }
2787 
2788 /// WriteInstruction - Emit an instruction to the specified stream.
2789 void ModuleBitcodeWriter::writeInstruction(const Instruction &I,
2790                                            unsigned InstID,
2791                                            SmallVectorImpl<unsigned> &Vals) {
2792   unsigned Code = 0;
2793   unsigned AbbrevToUse = 0;
2794   VE.setInstructionID(&I);
2795   switch (I.getOpcode()) {
2796   default:
2797     if (Instruction::isCast(I.getOpcode())) {
2798       Code = bitc::FUNC_CODE_INST_CAST;
2799       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2800         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
2801       Vals.push_back(VE.getTypeID(I.getType()));
2802       Vals.push_back(getEncodedCastOpcode(I.getOpcode()));
2803     } else {
2804       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
2805       Code = bitc::FUNC_CODE_INST_BINOP;
2806       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2807         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
2808       pushValue(I.getOperand(1), InstID, Vals);
2809       Vals.push_back(getEncodedBinaryOpcode(I.getOpcode()));
2810       uint64_t Flags = getOptimizationFlags(&I);
2811       if (Flags != 0) {
2812         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
2813           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
2814         Vals.push_back(Flags);
2815       }
2816     }
2817     break;
2818   case Instruction::FNeg: {
2819     Code = bitc::FUNC_CODE_INST_UNOP;
2820     if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2821       AbbrevToUse = FUNCTION_INST_UNOP_ABBREV;
2822     Vals.push_back(getEncodedUnaryOpcode(I.getOpcode()));
2823     uint64_t Flags = getOptimizationFlags(&I);
2824     if (Flags != 0) {
2825       if (AbbrevToUse == FUNCTION_INST_UNOP_ABBREV)
2826         AbbrevToUse = FUNCTION_INST_UNOP_FLAGS_ABBREV;
2827       Vals.push_back(Flags);
2828     }
2829     break;
2830   }
2831   case Instruction::GetElementPtr: {
2832     Code = bitc::FUNC_CODE_INST_GEP;
2833     AbbrevToUse = FUNCTION_INST_GEP_ABBREV;
2834     auto &GEPInst = cast<GetElementPtrInst>(I);
2835     Vals.push_back(GEPInst.isInBounds());
2836     Vals.push_back(VE.getTypeID(GEPInst.getSourceElementType()));
2837     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
2838       pushValueAndType(I.getOperand(i), InstID, Vals);
2839     break;
2840   }
2841   case Instruction::ExtractValue: {
2842     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
2843     pushValueAndType(I.getOperand(0), InstID, Vals);
2844     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
2845     Vals.append(EVI->idx_begin(), EVI->idx_end());
2846     break;
2847   }
2848   case Instruction::InsertValue: {
2849     Code = bitc::FUNC_CODE_INST_INSERTVAL;
2850     pushValueAndType(I.getOperand(0), InstID, Vals);
2851     pushValueAndType(I.getOperand(1), InstID, Vals);
2852     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
2853     Vals.append(IVI->idx_begin(), IVI->idx_end());
2854     break;
2855   }
2856   case Instruction::Select: {
2857     Code = bitc::FUNC_CODE_INST_VSELECT;
2858     pushValueAndType(I.getOperand(1), InstID, Vals);
2859     pushValue(I.getOperand(2), InstID, Vals);
2860     pushValueAndType(I.getOperand(0), InstID, Vals);
2861     uint64_t Flags = getOptimizationFlags(&I);
2862     if (Flags != 0)
2863       Vals.push_back(Flags);
2864     break;
2865   }
2866   case Instruction::ExtractElement:
2867     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
2868     pushValueAndType(I.getOperand(0), InstID, Vals);
2869     pushValueAndType(I.getOperand(1), InstID, Vals);
2870     break;
2871   case Instruction::InsertElement:
2872     Code = bitc::FUNC_CODE_INST_INSERTELT;
2873     pushValueAndType(I.getOperand(0), InstID, Vals);
2874     pushValue(I.getOperand(1), InstID, Vals);
2875     pushValueAndType(I.getOperand(2), InstID, Vals);
2876     break;
2877   case Instruction::ShuffleVector:
2878     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
2879     pushValueAndType(I.getOperand(0), InstID, Vals);
2880     pushValue(I.getOperand(1), InstID, Vals);
2881     pushValue(cast<ShuffleVectorInst>(I).getShuffleMaskForBitcode(), InstID,
2882               Vals);
2883     break;
2884   case Instruction::ICmp:
2885   case Instruction::FCmp: {
2886     // compare returning Int1Ty or vector of Int1Ty
2887     Code = bitc::FUNC_CODE_INST_CMP2;
2888     pushValueAndType(I.getOperand(0), InstID, Vals);
2889     pushValue(I.getOperand(1), InstID, Vals);
2890     Vals.push_back(cast<CmpInst>(I).getPredicate());
2891     uint64_t Flags = getOptimizationFlags(&I);
2892     if (Flags != 0)
2893       Vals.push_back(Flags);
2894     break;
2895   }
2896 
2897   case Instruction::Ret:
2898     {
2899       Code = bitc::FUNC_CODE_INST_RET;
2900       unsigned NumOperands = I.getNumOperands();
2901       if (NumOperands == 0)
2902         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
2903       else if (NumOperands == 1) {
2904         if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2905           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
2906       } else {
2907         for (unsigned i = 0, e = NumOperands; i != e; ++i)
2908           pushValueAndType(I.getOperand(i), InstID, Vals);
2909       }
2910     }
2911     break;
2912   case Instruction::Br:
2913     {
2914       Code = bitc::FUNC_CODE_INST_BR;
2915       const BranchInst &II = cast<BranchInst>(I);
2916       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
2917       if (II.isConditional()) {
2918         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
2919         pushValue(II.getCondition(), InstID, Vals);
2920       }
2921     }
2922     break;
2923   case Instruction::Switch:
2924     {
2925       Code = bitc::FUNC_CODE_INST_SWITCH;
2926       const SwitchInst &SI = cast<SwitchInst>(I);
2927       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
2928       pushValue(SI.getCondition(), InstID, Vals);
2929       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
2930       for (auto Case : SI.cases()) {
2931         Vals.push_back(VE.getValueID(Case.getCaseValue()));
2932         Vals.push_back(VE.getValueID(Case.getCaseSuccessor()));
2933       }
2934     }
2935     break;
2936   case Instruction::IndirectBr:
2937     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
2938     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2939     // Encode the address operand as relative, but not the basic blocks.
2940     pushValue(I.getOperand(0), InstID, Vals);
2941     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
2942       Vals.push_back(VE.getValueID(I.getOperand(i)));
2943     break;
2944 
2945   case Instruction::Invoke: {
2946     const InvokeInst *II = cast<InvokeInst>(&I);
2947     const Value *Callee = II->getCalledOperand();
2948     FunctionType *FTy = II->getFunctionType();
2949 
2950     if (II->hasOperandBundles())
2951       writeOperandBundles(*II, InstID);
2952 
2953     Code = bitc::FUNC_CODE_INST_INVOKE;
2954 
2955     Vals.push_back(VE.getAttributeListID(II->getAttributes()));
2956     Vals.push_back(II->getCallingConv() | 1 << 13);
2957     Vals.push_back(VE.getValueID(II->getNormalDest()));
2958     Vals.push_back(VE.getValueID(II->getUnwindDest()));
2959     Vals.push_back(VE.getTypeID(FTy));
2960     pushValueAndType(Callee, InstID, Vals);
2961 
2962     // Emit value #'s for the fixed parameters.
2963     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
2964       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
2965 
2966     // Emit type/value pairs for varargs params.
2967     if (FTy->isVarArg()) {
2968       for (unsigned i = FTy->getNumParams(), e = II->arg_size(); i != e; ++i)
2969         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
2970     }
2971     break;
2972   }
2973   case Instruction::Resume:
2974     Code = bitc::FUNC_CODE_INST_RESUME;
2975     pushValueAndType(I.getOperand(0), InstID, Vals);
2976     break;
2977   case Instruction::CleanupRet: {
2978     Code = bitc::FUNC_CODE_INST_CLEANUPRET;
2979     const auto &CRI = cast<CleanupReturnInst>(I);
2980     pushValue(CRI.getCleanupPad(), InstID, Vals);
2981     if (CRI.hasUnwindDest())
2982       Vals.push_back(VE.getValueID(CRI.getUnwindDest()));
2983     break;
2984   }
2985   case Instruction::CatchRet: {
2986     Code = bitc::FUNC_CODE_INST_CATCHRET;
2987     const auto &CRI = cast<CatchReturnInst>(I);
2988     pushValue(CRI.getCatchPad(), InstID, Vals);
2989     Vals.push_back(VE.getValueID(CRI.getSuccessor()));
2990     break;
2991   }
2992   case Instruction::CleanupPad:
2993   case Instruction::CatchPad: {
2994     const auto &FuncletPad = cast<FuncletPadInst>(I);
2995     Code = isa<CatchPadInst>(FuncletPad) ? bitc::FUNC_CODE_INST_CATCHPAD
2996                                          : bitc::FUNC_CODE_INST_CLEANUPPAD;
2997     pushValue(FuncletPad.getParentPad(), InstID, Vals);
2998 
2999     unsigned NumArgOperands = FuncletPad.arg_size();
3000     Vals.push_back(NumArgOperands);
3001     for (unsigned Op = 0; Op != NumArgOperands; ++Op)
3002       pushValueAndType(FuncletPad.getArgOperand(Op), InstID, Vals);
3003     break;
3004   }
3005   case Instruction::CatchSwitch: {
3006     Code = bitc::FUNC_CODE_INST_CATCHSWITCH;
3007     const auto &CatchSwitch = cast<CatchSwitchInst>(I);
3008 
3009     pushValue(CatchSwitch.getParentPad(), InstID, Vals);
3010 
3011     unsigned NumHandlers = CatchSwitch.getNumHandlers();
3012     Vals.push_back(NumHandlers);
3013     for (const BasicBlock *CatchPadBB : CatchSwitch.handlers())
3014       Vals.push_back(VE.getValueID(CatchPadBB));
3015 
3016     if (CatchSwitch.hasUnwindDest())
3017       Vals.push_back(VE.getValueID(CatchSwitch.getUnwindDest()));
3018     break;
3019   }
3020   case Instruction::CallBr: {
3021     const CallBrInst *CBI = cast<CallBrInst>(&I);
3022     const Value *Callee = CBI->getCalledOperand();
3023     FunctionType *FTy = CBI->getFunctionType();
3024 
3025     if (CBI->hasOperandBundles())
3026       writeOperandBundles(*CBI, InstID);
3027 
3028     Code = bitc::FUNC_CODE_INST_CALLBR;
3029 
3030     Vals.push_back(VE.getAttributeListID(CBI->getAttributes()));
3031 
3032     Vals.push_back(CBI->getCallingConv() << bitc::CALL_CCONV |
3033                    1 << bitc::CALL_EXPLICIT_TYPE);
3034 
3035     Vals.push_back(VE.getValueID(CBI->getDefaultDest()));
3036     Vals.push_back(CBI->getNumIndirectDests());
3037     for (unsigned i = 0, e = CBI->getNumIndirectDests(); i != e; ++i)
3038       Vals.push_back(VE.getValueID(CBI->getIndirectDest(i)));
3039 
3040     Vals.push_back(VE.getTypeID(FTy));
3041     pushValueAndType(Callee, InstID, Vals);
3042 
3043     // Emit value #'s for the fixed parameters.
3044     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
3045       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
3046 
3047     // Emit type/value pairs for varargs params.
3048     if (FTy->isVarArg()) {
3049       for (unsigned i = FTy->getNumParams(), e = CBI->arg_size(); i != e; ++i)
3050         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
3051     }
3052     break;
3053   }
3054   case Instruction::Unreachable:
3055     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
3056     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
3057     break;
3058 
3059   case Instruction::PHI: {
3060     const PHINode &PN = cast<PHINode>(I);
3061     Code = bitc::FUNC_CODE_INST_PHI;
3062     // With the newer instruction encoding, forward references could give
3063     // negative valued IDs.  This is most common for PHIs, so we use
3064     // signed VBRs.
3065     SmallVector<uint64_t, 128> Vals64;
3066     Vals64.push_back(VE.getTypeID(PN.getType()));
3067     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
3068       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64);
3069       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
3070     }
3071 
3072     uint64_t Flags = getOptimizationFlags(&I);
3073     if (Flags != 0)
3074       Vals64.push_back(Flags);
3075 
3076     // Emit a Vals64 vector and exit.
3077     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
3078     Vals64.clear();
3079     return;
3080   }
3081 
3082   case Instruction::LandingPad: {
3083     const LandingPadInst &LP = cast<LandingPadInst>(I);
3084     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
3085     Vals.push_back(VE.getTypeID(LP.getType()));
3086     Vals.push_back(LP.isCleanup());
3087     Vals.push_back(LP.getNumClauses());
3088     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
3089       if (LP.isCatch(I))
3090         Vals.push_back(LandingPadInst::Catch);
3091       else
3092         Vals.push_back(LandingPadInst::Filter);
3093       pushValueAndType(LP.getClause(I), InstID, Vals);
3094     }
3095     break;
3096   }
3097 
3098   case Instruction::Alloca: {
3099     Code = bitc::FUNC_CODE_INST_ALLOCA;
3100     const AllocaInst &AI = cast<AllocaInst>(I);
3101     Vals.push_back(VE.getTypeID(AI.getAllocatedType()));
3102     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
3103     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
3104     using APV = AllocaPackedValues;
3105     unsigned Record = 0;
3106     unsigned EncodedAlign = getEncodedAlign(AI.getAlign());
3107     Bitfield::set<APV::AlignLower>(
3108         Record, EncodedAlign & ((1 << APV::AlignLower::Bits) - 1));
3109     Bitfield::set<APV::AlignUpper>(Record,
3110                                    EncodedAlign >> APV::AlignLower::Bits);
3111     Bitfield::set<APV::UsedWithInAlloca>(Record, AI.isUsedWithInAlloca());
3112     Bitfield::set<APV::ExplicitType>(Record, true);
3113     Bitfield::set<APV::SwiftError>(Record, AI.isSwiftError());
3114     Vals.push_back(Record);
3115 
3116     unsigned AS = AI.getAddressSpace();
3117     if (AS != M.getDataLayout().getAllocaAddrSpace())
3118       Vals.push_back(AS);
3119     break;
3120   }
3121 
3122   case Instruction::Load:
3123     if (cast<LoadInst>(I).isAtomic()) {
3124       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
3125       pushValueAndType(I.getOperand(0), InstID, Vals);
3126     } else {
3127       Code = bitc::FUNC_CODE_INST_LOAD;
3128       if (!pushValueAndType(I.getOperand(0), InstID, Vals)) // ptr
3129         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
3130     }
3131     Vals.push_back(VE.getTypeID(I.getType()));
3132     Vals.push_back(getEncodedAlign(cast<LoadInst>(I).getAlign()));
3133     Vals.push_back(cast<LoadInst>(I).isVolatile());
3134     if (cast<LoadInst>(I).isAtomic()) {
3135       Vals.push_back(getEncodedOrdering(cast<LoadInst>(I).getOrdering()));
3136       Vals.push_back(getEncodedSyncScopeID(cast<LoadInst>(I).getSyncScopeID()));
3137     }
3138     break;
3139   case Instruction::Store:
3140     if (cast<StoreInst>(I).isAtomic())
3141       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
3142     else
3143       Code = bitc::FUNC_CODE_INST_STORE;
3144     pushValueAndType(I.getOperand(1), InstID, Vals); // ptrty + ptr
3145     pushValueAndType(I.getOperand(0), InstID, Vals); // valty + val
3146     Vals.push_back(getEncodedAlign(cast<StoreInst>(I).getAlign()));
3147     Vals.push_back(cast<StoreInst>(I).isVolatile());
3148     if (cast<StoreInst>(I).isAtomic()) {
3149       Vals.push_back(getEncodedOrdering(cast<StoreInst>(I).getOrdering()));
3150       Vals.push_back(
3151           getEncodedSyncScopeID(cast<StoreInst>(I).getSyncScopeID()));
3152     }
3153     break;
3154   case Instruction::AtomicCmpXchg:
3155     Code = bitc::FUNC_CODE_INST_CMPXCHG;
3156     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
3157     pushValueAndType(I.getOperand(1), InstID, Vals); // cmp.
3158     pushValue(I.getOperand(2), InstID, Vals);        // newval.
3159     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
3160     Vals.push_back(
3161         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
3162     Vals.push_back(
3163         getEncodedSyncScopeID(cast<AtomicCmpXchgInst>(I).getSyncScopeID()));
3164     Vals.push_back(
3165         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
3166     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
3167     Vals.push_back(getEncodedAlign(cast<AtomicCmpXchgInst>(I).getAlign()));
3168     break;
3169   case Instruction::AtomicRMW:
3170     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
3171     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
3172     pushValueAndType(I.getOperand(1), InstID, Vals); // valty + val
3173     Vals.push_back(
3174         getEncodedRMWOperation(cast<AtomicRMWInst>(I).getOperation()));
3175     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
3176     Vals.push_back(getEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
3177     Vals.push_back(
3178         getEncodedSyncScopeID(cast<AtomicRMWInst>(I).getSyncScopeID()));
3179     Vals.push_back(getEncodedAlign(cast<AtomicRMWInst>(I).getAlign()));
3180     break;
3181   case Instruction::Fence:
3182     Code = bitc::FUNC_CODE_INST_FENCE;
3183     Vals.push_back(getEncodedOrdering(cast<FenceInst>(I).getOrdering()));
3184     Vals.push_back(getEncodedSyncScopeID(cast<FenceInst>(I).getSyncScopeID()));
3185     break;
3186   case Instruction::Call: {
3187     const CallInst &CI = cast<CallInst>(I);
3188     FunctionType *FTy = CI.getFunctionType();
3189 
3190     if (CI.hasOperandBundles())
3191       writeOperandBundles(CI, InstID);
3192 
3193     Code = bitc::FUNC_CODE_INST_CALL;
3194 
3195     Vals.push_back(VE.getAttributeListID(CI.getAttributes()));
3196 
3197     unsigned Flags = getOptimizationFlags(&I);
3198     Vals.push_back(CI.getCallingConv() << bitc::CALL_CCONV |
3199                    unsigned(CI.isTailCall()) << bitc::CALL_TAIL |
3200                    unsigned(CI.isMustTailCall()) << bitc::CALL_MUSTTAIL |
3201                    1 << bitc::CALL_EXPLICIT_TYPE |
3202                    unsigned(CI.isNoTailCall()) << bitc::CALL_NOTAIL |
3203                    unsigned(Flags != 0) << bitc::CALL_FMF);
3204     if (Flags != 0)
3205       Vals.push_back(Flags);
3206 
3207     Vals.push_back(VE.getTypeID(FTy));
3208     pushValueAndType(CI.getCalledOperand(), InstID, Vals); // Callee
3209 
3210     // Emit value #'s for the fixed parameters.
3211     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
3212       // Check for labels (can happen with asm labels).
3213       if (FTy->getParamType(i)->isLabelTy())
3214         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
3215       else
3216         pushValue(CI.getArgOperand(i), InstID, Vals); // fixed param.
3217     }
3218 
3219     // Emit type/value pairs for varargs params.
3220     if (FTy->isVarArg()) {
3221       for (unsigned i = FTy->getNumParams(), e = CI.arg_size(); i != e; ++i)
3222         pushValueAndType(CI.getArgOperand(i), InstID, Vals); // varargs
3223     }
3224     break;
3225   }
3226   case Instruction::VAArg:
3227     Code = bitc::FUNC_CODE_INST_VAARG;
3228     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
3229     pushValue(I.getOperand(0), InstID, Vals);                   // valist.
3230     Vals.push_back(VE.getTypeID(I.getType())); // restype.
3231     break;
3232   case Instruction::Freeze:
3233     Code = bitc::FUNC_CODE_INST_FREEZE;
3234     pushValueAndType(I.getOperand(0), InstID, Vals);
3235     break;
3236   }
3237 
3238   Stream.EmitRecord(Code, Vals, AbbrevToUse);
3239   Vals.clear();
3240 }
3241 
3242 /// Write a GlobalValue VST to the module. The purpose of this data structure is
3243 /// to allow clients to efficiently find the function body.
3244 void ModuleBitcodeWriter::writeGlobalValueSymbolTable(
3245   DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3246   // Get the offset of the VST we are writing, and backpatch it into
3247   // the VST forward declaration record.
3248   uint64_t VSTOffset = Stream.GetCurrentBitNo();
3249   // The BitcodeStartBit was the stream offset of the identification block.
3250   VSTOffset -= bitcodeStartBit();
3251   assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
3252   // Note that we add 1 here because the offset is relative to one word
3253   // before the start of the identification block, which was historically
3254   // always the start of the regular bitcode header.
3255   Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32 + 1);
3256 
3257   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3258 
3259   auto Abbv = std::make_shared<BitCodeAbbrev>();
3260   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
3261   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
3262   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
3263   unsigned FnEntryAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3264 
3265   for (const Function &F : M) {
3266     uint64_t Record[2];
3267 
3268     if (F.isDeclaration())
3269       continue;
3270 
3271     Record[0] = VE.getValueID(&F);
3272 
3273     // Save the word offset of the function (from the start of the
3274     // actual bitcode written to the stream).
3275     uint64_t BitcodeIndex = FunctionToBitcodeIndex[&F] - bitcodeStartBit();
3276     assert((BitcodeIndex & 31) == 0 && "function block not 32-bit aligned");
3277     // Note that we add 1 here because the offset is relative to one word
3278     // before the start of the identification block, which was historically
3279     // always the start of the regular bitcode header.
3280     Record[1] = BitcodeIndex / 32 + 1;
3281 
3282     Stream.EmitRecord(bitc::VST_CODE_FNENTRY, Record, FnEntryAbbrev);
3283   }
3284 
3285   Stream.ExitBlock();
3286 }
3287 
3288 /// Emit names for arguments, instructions and basic blocks in a function.
3289 void ModuleBitcodeWriter::writeFunctionLevelValueSymbolTable(
3290     const ValueSymbolTable &VST) {
3291   if (VST.empty())
3292     return;
3293 
3294   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3295 
3296   // FIXME: Set up the abbrev, we know how many values there are!
3297   // FIXME: We know if the type names can use 7-bit ascii.
3298   SmallVector<uint64_t, 64> NameVals;
3299 
3300   for (const ValueName &Name : VST) {
3301     // Figure out the encoding to use for the name.
3302     StringEncoding Bits = getStringEncoding(Name.getKey());
3303 
3304     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
3305     NameVals.push_back(VE.getValueID(Name.getValue()));
3306 
3307     // VST_CODE_ENTRY:   [valueid, namechar x N]
3308     // VST_CODE_BBENTRY: [bbid, namechar x N]
3309     unsigned Code;
3310     if (isa<BasicBlock>(Name.getValue())) {
3311       Code = bitc::VST_CODE_BBENTRY;
3312       if (Bits == SE_Char6)
3313         AbbrevToUse = VST_BBENTRY_6_ABBREV;
3314     } else {
3315       Code = bitc::VST_CODE_ENTRY;
3316       if (Bits == SE_Char6)
3317         AbbrevToUse = VST_ENTRY_6_ABBREV;
3318       else if (Bits == SE_Fixed7)
3319         AbbrevToUse = VST_ENTRY_7_ABBREV;
3320     }
3321 
3322     for (const auto P : Name.getKey())
3323       NameVals.push_back((unsigned char)P);
3324 
3325     // Emit the finished record.
3326     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
3327     NameVals.clear();
3328   }
3329 
3330   Stream.ExitBlock();
3331 }
3332 
3333 void ModuleBitcodeWriter::writeUseList(UseListOrder &&Order) {
3334   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
3335   unsigned Code;
3336   if (isa<BasicBlock>(Order.V))
3337     Code = bitc::USELIST_CODE_BB;
3338   else
3339     Code = bitc::USELIST_CODE_DEFAULT;
3340 
3341   SmallVector<uint64_t, 64> Record(Order.Shuffle.begin(), Order.Shuffle.end());
3342   Record.push_back(VE.getValueID(Order.V));
3343   Stream.EmitRecord(Code, Record);
3344 }
3345 
3346 void ModuleBitcodeWriter::writeUseListBlock(const Function *F) {
3347   assert(VE.shouldPreserveUseListOrder() &&
3348          "Expected to be preserving use-list order");
3349 
3350   auto hasMore = [&]() {
3351     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
3352   };
3353   if (!hasMore())
3354     // Nothing to do.
3355     return;
3356 
3357   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
3358   while (hasMore()) {
3359     writeUseList(std::move(VE.UseListOrders.back()));
3360     VE.UseListOrders.pop_back();
3361   }
3362   Stream.ExitBlock();
3363 }
3364 
3365 /// Emit a function body to the module stream.
3366 void ModuleBitcodeWriter::writeFunction(
3367     const Function &F,
3368     DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3369   // Save the bitcode index of the start of this function block for recording
3370   // in the VST.
3371   FunctionToBitcodeIndex[&F] = Stream.GetCurrentBitNo();
3372 
3373   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
3374   VE.incorporateFunction(F);
3375 
3376   SmallVector<unsigned, 64> Vals;
3377 
3378   // Emit the number of basic blocks, so the reader can create them ahead of
3379   // time.
3380   Vals.push_back(VE.getBasicBlocks().size());
3381   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
3382   Vals.clear();
3383 
3384   // If there are function-local constants, emit them now.
3385   unsigned CstStart, CstEnd;
3386   VE.getFunctionConstantRange(CstStart, CstEnd);
3387   writeConstants(CstStart, CstEnd, false);
3388 
3389   // If there is function-local metadata, emit it now.
3390   writeFunctionMetadata(F);
3391 
3392   // Keep a running idea of what the instruction ID is.
3393   unsigned InstID = CstEnd;
3394 
3395   bool NeedsMetadataAttachment = F.hasMetadata();
3396 
3397   DILocation *LastDL = nullptr;
3398   SmallSetVector<Function *, 4> BlockAddressUsers;
3399 
3400   // Finally, emit all the instructions, in order.
3401   for (const BasicBlock &BB : F) {
3402     for (const Instruction &I : BB) {
3403       writeInstruction(I, InstID, Vals);
3404 
3405       if (!I.getType()->isVoidTy())
3406         ++InstID;
3407 
3408       // If the instruction has metadata, write a metadata attachment later.
3409       NeedsMetadataAttachment |= I.hasMetadataOtherThanDebugLoc();
3410 
3411       // If the instruction has a debug location, emit it.
3412       DILocation *DL = I.getDebugLoc();
3413       if (!DL)
3414         continue;
3415 
3416       if (DL == LastDL) {
3417         // Just repeat the same debug loc as last time.
3418         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
3419         continue;
3420       }
3421 
3422       Vals.push_back(DL->getLine());
3423       Vals.push_back(DL->getColumn());
3424       Vals.push_back(VE.getMetadataOrNullID(DL->getScope()));
3425       Vals.push_back(VE.getMetadataOrNullID(DL->getInlinedAt()));
3426       Vals.push_back(DL->isImplicitCode());
3427       Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
3428       Vals.clear();
3429 
3430       LastDL = DL;
3431     }
3432 
3433     if (BlockAddress *BA = BlockAddress::lookup(&BB)) {
3434       SmallVector<Value *> Worklist{BA};
3435       SmallPtrSet<Value *, 8> Visited{BA};
3436       while (!Worklist.empty()) {
3437         Value *V = Worklist.pop_back_val();
3438         for (User *U : V->users()) {
3439           if (auto *I = dyn_cast<Instruction>(U)) {
3440             Function *P = I->getFunction();
3441             if (P != &F)
3442               BlockAddressUsers.insert(P);
3443           } else if (isa<Constant>(U) && !isa<GlobalValue>(U) &&
3444                      Visited.insert(U).second)
3445             Worklist.push_back(U);
3446         }
3447       }
3448     }
3449   }
3450 
3451   if (!BlockAddressUsers.empty()) {
3452     Vals.resize(BlockAddressUsers.size());
3453     for (auto I : llvm::enumerate(BlockAddressUsers))
3454       Vals[I.index()] = VE.getValueID(I.value());
3455     Stream.EmitRecord(bitc::FUNC_CODE_BLOCKADDR_USERS, Vals);
3456     Vals.clear();
3457   }
3458 
3459   // Emit names for all the instructions etc.
3460   if (auto *Symtab = F.getValueSymbolTable())
3461     writeFunctionLevelValueSymbolTable(*Symtab);
3462 
3463   if (NeedsMetadataAttachment)
3464     writeFunctionMetadataAttachment(F);
3465   if (VE.shouldPreserveUseListOrder())
3466     writeUseListBlock(&F);
3467   VE.purgeFunction();
3468   Stream.ExitBlock();
3469 }
3470 
3471 // Emit blockinfo, which defines the standard abbreviations etc.
3472 void ModuleBitcodeWriter::writeBlockInfo() {
3473   // We only want to emit block info records for blocks that have multiple
3474   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
3475   // Other blocks can define their abbrevs inline.
3476   Stream.EnterBlockInfoBlock();
3477 
3478   { // 8-bit fixed-width VST_CODE_ENTRY/VST_CODE_BBENTRY strings.
3479     auto Abbv = std::make_shared<BitCodeAbbrev>();
3480     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
3481     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3482     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3483     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3484     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3485         VST_ENTRY_8_ABBREV)
3486       llvm_unreachable("Unexpected abbrev ordering!");
3487   }
3488 
3489   { // 7-bit fixed width VST_CODE_ENTRY strings.
3490     auto Abbv = std::make_shared<BitCodeAbbrev>();
3491     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3492     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3493     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3494     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3495     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3496         VST_ENTRY_7_ABBREV)
3497       llvm_unreachable("Unexpected abbrev ordering!");
3498   }
3499   { // 6-bit char6 VST_CODE_ENTRY strings.
3500     auto Abbv = std::make_shared<BitCodeAbbrev>();
3501     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3502     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3503     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3504     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3505     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3506         VST_ENTRY_6_ABBREV)
3507       llvm_unreachable("Unexpected abbrev ordering!");
3508   }
3509   { // 6-bit char6 VST_CODE_BBENTRY strings.
3510     auto Abbv = std::make_shared<BitCodeAbbrev>();
3511     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
3512     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3513     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3514     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3515     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3516         VST_BBENTRY_6_ABBREV)
3517       llvm_unreachable("Unexpected abbrev ordering!");
3518   }
3519 
3520   { // SETTYPE abbrev for CONSTANTS_BLOCK.
3521     auto Abbv = std::make_shared<BitCodeAbbrev>();
3522     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
3523     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
3524                               VE.computeBitsRequiredForTypeIndicies()));
3525     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3526         CONSTANTS_SETTYPE_ABBREV)
3527       llvm_unreachable("Unexpected abbrev ordering!");
3528   }
3529 
3530   { // INTEGER abbrev for CONSTANTS_BLOCK.
3531     auto Abbv = std::make_shared<BitCodeAbbrev>();
3532     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
3533     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3534     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3535         CONSTANTS_INTEGER_ABBREV)
3536       llvm_unreachable("Unexpected abbrev ordering!");
3537   }
3538 
3539   { // CE_CAST abbrev for CONSTANTS_BLOCK.
3540     auto Abbv = std::make_shared<BitCodeAbbrev>();
3541     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
3542     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
3543     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
3544                               VE.computeBitsRequiredForTypeIndicies()));
3545     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
3546 
3547     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3548         CONSTANTS_CE_CAST_Abbrev)
3549       llvm_unreachable("Unexpected abbrev ordering!");
3550   }
3551   { // NULL abbrev for CONSTANTS_BLOCK.
3552     auto Abbv = std::make_shared<BitCodeAbbrev>();
3553     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
3554     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3555         CONSTANTS_NULL_Abbrev)
3556       llvm_unreachable("Unexpected abbrev ordering!");
3557   }
3558 
3559   // FIXME: This should only use space for first class types!
3560 
3561   { // INST_LOAD abbrev for FUNCTION_BLOCK.
3562     auto Abbv = std::make_shared<BitCodeAbbrev>();
3563     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
3564     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
3565     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
3566                               VE.computeBitsRequiredForTypeIndicies()));
3567     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
3568     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
3569     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3570         FUNCTION_INST_LOAD_ABBREV)
3571       llvm_unreachable("Unexpected abbrev ordering!");
3572   }
3573   { // INST_UNOP abbrev for FUNCTION_BLOCK.
3574     auto Abbv = std::make_shared<BitCodeAbbrev>();
3575     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3576     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3577     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3578     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3579         FUNCTION_INST_UNOP_ABBREV)
3580       llvm_unreachable("Unexpected abbrev ordering!");
3581   }
3582   { // INST_UNOP_FLAGS abbrev for FUNCTION_BLOCK.
3583     auto Abbv = std::make_shared<BitCodeAbbrev>();
3584     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3585     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3586     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3587     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3588     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3589         FUNCTION_INST_UNOP_FLAGS_ABBREV)
3590       llvm_unreachable("Unexpected abbrev ordering!");
3591   }
3592   { // INST_BINOP abbrev for FUNCTION_BLOCK.
3593     auto Abbv = std::make_shared<BitCodeAbbrev>();
3594     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3595     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3596     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3597     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3598     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3599         FUNCTION_INST_BINOP_ABBREV)
3600       llvm_unreachable("Unexpected abbrev ordering!");
3601   }
3602   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
3603     auto Abbv = std::make_shared<BitCodeAbbrev>();
3604     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3605     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3606     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3607     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3608     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3609     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3610         FUNCTION_INST_BINOP_FLAGS_ABBREV)
3611       llvm_unreachable("Unexpected abbrev ordering!");
3612   }
3613   { // INST_CAST abbrev for FUNCTION_BLOCK.
3614     auto Abbv = std::make_shared<BitCodeAbbrev>();
3615     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
3616     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
3617     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
3618                               VE.computeBitsRequiredForTypeIndicies()));
3619     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
3620     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3621         FUNCTION_INST_CAST_ABBREV)
3622       llvm_unreachable("Unexpected abbrev ordering!");
3623   }
3624 
3625   { // INST_RET abbrev for FUNCTION_BLOCK.
3626     auto Abbv = std::make_shared<BitCodeAbbrev>();
3627     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3628     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3629         FUNCTION_INST_RET_VOID_ABBREV)
3630       llvm_unreachable("Unexpected abbrev ordering!");
3631   }
3632   { // INST_RET abbrev for FUNCTION_BLOCK.
3633     auto Abbv = std::make_shared<BitCodeAbbrev>();
3634     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3635     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
3636     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3637         FUNCTION_INST_RET_VAL_ABBREV)
3638       llvm_unreachable("Unexpected abbrev ordering!");
3639   }
3640   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
3641     auto Abbv = std::make_shared<BitCodeAbbrev>();
3642     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
3643     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3644         FUNCTION_INST_UNREACHABLE_ABBREV)
3645       llvm_unreachable("Unexpected abbrev ordering!");
3646   }
3647   {
3648     auto Abbv = std::make_shared<BitCodeAbbrev>();
3649     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_GEP));
3650     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
3651     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, // dest ty
3652                               Log2_32_Ceil(VE.getTypes().size() + 1)));
3653     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3654     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
3655     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3656         FUNCTION_INST_GEP_ABBREV)
3657       llvm_unreachable("Unexpected abbrev ordering!");
3658   }
3659 
3660   Stream.ExitBlock();
3661 }
3662 
3663 /// Write the module path strings, currently only used when generating
3664 /// a combined index file.
3665 void IndexBitcodeWriter::writeModStrings() {
3666   Stream.EnterSubblock(bitc::MODULE_STRTAB_BLOCK_ID, 3);
3667 
3668   // TODO: See which abbrev sizes we actually need to emit
3669 
3670   // 8-bit fixed-width MST_ENTRY strings.
3671   auto 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::Fixed, 8));
3676   unsigned Abbrev8Bit = Stream.EmitAbbrev(std::move(Abbv));
3677 
3678   // 7-bit fixed width MST_ENTRY strings.
3679   Abbv = std::make_shared<BitCodeAbbrev>();
3680   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3681   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3682   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3683   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3684   unsigned Abbrev7Bit = Stream.EmitAbbrev(std::move(Abbv));
3685 
3686   // 6-bit char6 MST_ENTRY strings.
3687   Abbv = std::make_shared<BitCodeAbbrev>();
3688   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3689   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3690   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3691   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3692   unsigned Abbrev6Bit = Stream.EmitAbbrev(std::move(Abbv));
3693 
3694   // Module Hash, 160 bits SHA1. Optionally, emitted after each MST_CODE_ENTRY.
3695   Abbv = std::make_shared<BitCodeAbbrev>();
3696   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_HASH));
3697   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3698   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3699   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3700   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3701   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3702   unsigned AbbrevHash = Stream.EmitAbbrev(std::move(Abbv));
3703 
3704   SmallVector<unsigned, 64> Vals;
3705   forEachModule(
3706       [&](const StringMapEntry<std::pair<uint64_t, ModuleHash>> &MPSE) {
3707         StringRef Key = MPSE.getKey();
3708         const auto &Value = MPSE.getValue();
3709         StringEncoding Bits = getStringEncoding(Key);
3710         unsigned AbbrevToUse = Abbrev8Bit;
3711         if (Bits == SE_Char6)
3712           AbbrevToUse = Abbrev6Bit;
3713         else if (Bits == SE_Fixed7)
3714           AbbrevToUse = Abbrev7Bit;
3715 
3716         Vals.push_back(Value.first);
3717         Vals.append(Key.begin(), Key.end());
3718 
3719         // Emit the finished record.
3720         Stream.EmitRecord(bitc::MST_CODE_ENTRY, Vals, AbbrevToUse);
3721 
3722         // Emit an optional hash for the module now
3723         const auto &Hash = Value.second;
3724         if (llvm::any_of(Hash, [](uint32_t H) { return H; })) {
3725           Vals.assign(Hash.begin(), Hash.end());
3726           // Emit the hash record.
3727           Stream.EmitRecord(bitc::MST_CODE_HASH, Vals, AbbrevHash);
3728         }
3729 
3730         Vals.clear();
3731       });
3732   Stream.ExitBlock();
3733 }
3734 
3735 /// Write the function type metadata related records that need to appear before
3736 /// a function summary entry (whether per-module or combined).
3737 template <typename Fn>
3738 static void writeFunctionTypeMetadataRecords(BitstreamWriter &Stream,
3739                                              FunctionSummary *FS,
3740                                              Fn GetValueID) {
3741   if (!FS->type_tests().empty())
3742     Stream.EmitRecord(bitc::FS_TYPE_TESTS, FS->type_tests());
3743 
3744   SmallVector<uint64_t, 64> Record;
3745 
3746   auto WriteVFuncIdVec = [&](uint64_t Ty,
3747                              ArrayRef<FunctionSummary::VFuncId> VFs) {
3748     if (VFs.empty())
3749       return;
3750     Record.clear();
3751     for (auto &VF : VFs) {
3752       Record.push_back(VF.GUID);
3753       Record.push_back(VF.Offset);
3754     }
3755     Stream.EmitRecord(Ty, Record);
3756   };
3757 
3758   WriteVFuncIdVec(bitc::FS_TYPE_TEST_ASSUME_VCALLS,
3759                   FS->type_test_assume_vcalls());
3760   WriteVFuncIdVec(bitc::FS_TYPE_CHECKED_LOAD_VCALLS,
3761                   FS->type_checked_load_vcalls());
3762 
3763   auto WriteConstVCallVec = [&](uint64_t Ty,
3764                                 ArrayRef<FunctionSummary::ConstVCall> VCs) {
3765     for (auto &VC : VCs) {
3766       Record.clear();
3767       Record.push_back(VC.VFunc.GUID);
3768       Record.push_back(VC.VFunc.Offset);
3769       llvm::append_range(Record, VC.Args);
3770       Stream.EmitRecord(Ty, Record);
3771     }
3772   };
3773 
3774   WriteConstVCallVec(bitc::FS_TYPE_TEST_ASSUME_CONST_VCALL,
3775                      FS->type_test_assume_const_vcalls());
3776   WriteConstVCallVec(bitc::FS_TYPE_CHECKED_LOAD_CONST_VCALL,
3777                      FS->type_checked_load_const_vcalls());
3778 
3779   auto WriteRange = [&](ConstantRange Range) {
3780     Range = Range.sextOrTrunc(FunctionSummary::ParamAccess::RangeWidth);
3781     assert(Range.getLower().getNumWords() == 1);
3782     assert(Range.getUpper().getNumWords() == 1);
3783     emitSignedInt64(Record, *Range.getLower().getRawData());
3784     emitSignedInt64(Record, *Range.getUpper().getRawData());
3785   };
3786 
3787   if (!FS->paramAccesses().empty()) {
3788     Record.clear();
3789     for (auto &Arg : FS->paramAccesses()) {
3790       size_t UndoSize = Record.size();
3791       Record.push_back(Arg.ParamNo);
3792       WriteRange(Arg.Use);
3793       Record.push_back(Arg.Calls.size());
3794       for (auto &Call : Arg.Calls) {
3795         Record.push_back(Call.ParamNo);
3796         Optional<unsigned> ValueID = GetValueID(Call.Callee);
3797         if (!ValueID) {
3798           // If ValueID is unknown we can't drop just this call, we must drop
3799           // entire parameter.
3800           Record.resize(UndoSize);
3801           break;
3802         }
3803         Record.push_back(*ValueID);
3804         WriteRange(Call.Offsets);
3805       }
3806     }
3807     if (!Record.empty())
3808       Stream.EmitRecord(bitc::FS_PARAM_ACCESS, Record);
3809   }
3810 }
3811 
3812 /// Collect type IDs from type tests used by function.
3813 static void
3814 getReferencedTypeIds(FunctionSummary *FS,
3815                      std::set<GlobalValue::GUID> &ReferencedTypeIds) {
3816   if (!FS->type_tests().empty())
3817     for (auto &TT : FS->type_tests())
3818       ReferencedTypeIds.insert(TT);
3819 
3820   auto GetReferencedTypesFromVFuncIdVec =
3821       [&](ArrayRef<FunctionSummary::VFuncId> VFs) {
3822         for (auto &VF : VFs)
3823           ReferencedTypeIds.insert(VF.GUID);
3824       };
3825 
3826   GetReferencedTypesFromVFuncIdVec(FS->type_test_assume_vcalls());
3827   GetReferencedTypesFromVFuncIdVec(FS->type_checked_load_vcalls());
3828 
3829   auto GetReferencedTypesFromConstVCallVec =
3830       [&](ArrayRef<FunctionSummary::ConstVCall> VCs) {
3831         for (auto &VC : VCs)
3832           ReferencedTypeIds.insert(VC.VFunc.GUID);
3833       };
3834 
3835   GetReferencedTypesFromConstVCallVec(FS->type_test_assume_const_vcalls());
3836   GetReferencedTypesFromConstVCallVec(FS->type_checked_load_const_vcalls());
3837 }
3838 
3839 static void writeWholeProgramDevirtResolutionByArg(
3840     SmallVector<uint64_t, 64> &NameVals, const std::vector<uint64_t> &args,
3841     const WholeProgramDevirtResolution::ByArg &ByArg) {
3842   NameVals.push_back(args.size());
3843   llvm::append_range(NameVals, args);
3844 
3845   NameVals.push_back(ByArg.TheKind);
3846   NameVals.push_back(ByArg.Info);
3847   NameVals.push_back(ByArg.Byte);
3848   NameVals.push_back(ByArg.Bit);
3849 }
3850 
3851 static void writeWholeProgramDevirtResolution(
3852     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3853     uint64_t Id, const WholeProgramDevirtResolution &Wpd) {
3854   NameVals.push_back(Id);
3855 
3856   NameVals.push_back(Wpd.TheKind);
3857   NameVals.push_back(StrtabBuilder.add(Wpd.SingleImplName));
3858   NameVals.push_back(Wpd.SingleImplName.size());
3859 
3860   NameVals.push_back(Wpd.ResByArg.size());
3861   for (auto &A : Wpd.ResByArg)
3862     writeWholeProgramDevirtResolutionByArg(NameVals, A.first, A.second);
3863 }
3864 
3865 static void writeTypeIdSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
3866                                      StringTableBuilder &StrtabBuilder,
3867                                      const std::string &Id,
3868                                      const TypeIdSummary &Summary) {
3869   NameVals.push_back(StrtabBuilder.add(Id));
3870   NameVals.push_back(Id.size());
3871 
3872   NameVals.push_back(Summary.TTRes.TheKind);
3873   NameVals.push_back(Summary.TTRes.SizeM1BitWidth);
3874   NameVals.push_back(Summary.TTRes.AlignLog2);
3875   NameVals.push_back(Summary.TTRes.SizeM1);
3876   NameVals.push_back(Summary.TTRes.BitMask);
3877   NameVals.push_back(Summary.TTRes.InlineBits);
3878 
3879   for (auto &W : Summary.WPDRes)
3880     writeWholeProgramDevirtResolution(NameVals, StrtabBuilder, W.first,
3881                                       W.second);
3882 }
3883 
3884 static void writeTypeIdCompatibleVtableSummaryRecord(
3885     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3886     const std::string &Id, const TypeIdCompatibleVtableInfo &Summary,
3887     ValueEnumerator &VE) {
3888   NameVals.push_back(StrtabBuilder.add(Id));
3889   NameVals.push_back(Id.size());
3890 
3891   for (auto &P : Summary) {
3892     NameVals.push_back(P.AddressPointOffset);
3893     NameVals.push_back(VE.getValueID(P.VTableVI.getValue()));
3894   }
3895 }
3896 
3897 // Helper to emit a single function summary record.
3898 void ModuleBitcodeWriterBase::writePerModuleFunctionSummaryRecord(
3899     SmallVector<uint64_t, 64> &NameVals, GlobalValueSummary *Summary,
3900     unsigned ValueID, unsigned FSCallsAbbrev, unsigned FSCallsProfileAbbrev,
3901     const Function &F) {
3902   NameVals.push_back(ValueID);
3903 
3904   FunctionSummary *FS = cast<FunctionSummary>(Summary);
3905 
3906   writeFunctionTypeMetadataRecords(
3907       Stream, FS, [&](const ValueInfo &VI) -> Optional<unsigned> {
3908         return {VE.getValueID(VI.getValue())};
3909       });
3910 
3911   auto SpecialRefCnts = FS->specialRefCounts();
3912   NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
3913   NameVals.push_back(FS->instCount());
3914   NameVals.push_back(getEncodedFFlags(FS->fflags()));
3915   NameVals.push_back(FS->refs().size());
3916   NameVals.push_back(SpecialRefCnts.first);  // rorefcnt
3917   NameVals.push_back(SpecialRefCnts.second); // worefcnt
3918 
3919   for (auto &RI : FS->refs())
3920     NameVals.push_back(VE.getValueID(RI.getValue()));
3921 
3922   bool HasProfileData =
3923       F.hasProfileData() || ForceSummaryEdgesCold != FunctionSummary::FSHT_None;
3924   for (auto &ECI : FS->calls()) {
3925     NameVals.push_back(getValueId(ECI.first));
3926     if (HasProfileData)
3927       NameVals.push_back(static_cast<uint8_t>(ECI.second.Hotness));
3928     else if (WriteRelBFToSummary)
3929       NameVals.push_back(ECI.second.RelBlockFreq);
3930   }
3931 
3932   unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
3933   unsigned Code =
3934       (HasProfileData ? bitc::FS_PERMODULE_PROFILE
3935                       : (WriteRelBFToSummary ? bitc::FS_PERMODULE_RELBF
3936                                              : bitc::FS_PERMODULE));
3937 
3938   // Emit the finished record.
3939   Stream.EmitRecord(Code, NameVals, FSAbbrev);
3940   NameVals.clear();
3941 }
3942 
3943 // Collect the global value references in the given variable's initializer,
3944 // and emit them in a summary record.
3945 void ModuleBitcodeWriterBase::writeModuleLevelReferences(
3946     const GlobalVariable &V, SmallVector<uint64_t, 64> &NameVals,
3947     unsigned FSModRefsAbbrev, unsigned FSModVTableRefsAbbrev) {
3948   auto VI = Index->getValueInfo(V.getGUID());
3949   if (!VI || VI.getSummaryList().empty()) {
3950     // Only declarations should not have a summary (a declaration might however
3951     // have a summary if the def was in module level asm).
3952     assert(V.isDeclaration());
3953     return;
3954   }
3955   auto *Summary = VI.getSummaryList()[0].get();
3956   NameVals.push_back(VE.getValueID(&V));
3957   GlobalVarSummary *VS = cast<GlobalVarSummary>(Summary);
3958   NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
3959   NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
3960 
3961   auto VTableFuncs = VS->vTableFuncs();
3962   if (!VTableFuncs.empty())
3963     NameVals.push_back(VS->refs().size());
3964 
3965   unsigned SizeBeforeRefs = NameVals.size();
3966   for (auto &RI : VS->refs())
3967     NameVals.push_back(VE.getValueID(RI.getValue()));
3968   // Sort the refs for determinism output, the vector returned by FS->refs() has
3969   // been initialized from a DenseSet.
3970   llvm::sort(drop_begin(NameVals, SizeBeforeRefs));
3971 
3972   if (VTableFuncs.empty())
3973     Stream.EmitRecord(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS, NameVals,
3974                       FSModRefsAbbrev);
3975   else {
3976     // VTableFuncs pairs should already be sorted by offset.
3977     for (auto &P : VTableFuncs) {
3978       NameVals.push_back(VE.getValueID(P.FuncVI.getValue()));
3979       NameVals.push_back(P.VTableOffset);
3980     }
3981 
3982     Stream.EmitRecord(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS, NameVals,
3983                       FSModVTableRefsAbbrev);
3984   }
3985   NameVals.clear();
3986 }
3987 
3988 /// Emit the per-module summary section alongside the rest of
3989 /// the module's bitcode.
3990 void ModuleBitcodeWriterBase::writePerModuleGlobalValueSummary() {
3991   // By default we compile with ThinLTO if the module has a summary, but the
3992   // client can request full LTO with a module flag.
3993   bool IsThinLTO = true;
3994   if (auto *MD =
3995           mdconst::extract_or_null<ConstantInt>(M.getModuleFlag("ThinLTO")))
3996     IsThinLTO = MD->getZExtValue();
3997   Stream.EnterSubblock(IsThinLTO ? bitc::GLOBALVAL_SUMMARY_BLOCK_ID
3998                                  : bitc::FULL_LTO_GLOBALVAL_SUMMARY_BLOCK_ID,
3999                        4);
4000 
4001   Stream.EmitRecord(
4002       bitc::FS_VERSION,
4003       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
4004 
4005   // Write the index flags.
4006   uint64_t Flags = 0;
4007   // Bits 1-3 are set only in the combined index, skip them.
4008   if (Index->enableSplitLTOUnit())
4009     Flags |= 0x8;
4010   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Flags});
4011 
4012   if (Index->begin() == Index->end()) {
4013     Stream.ExitBlock();
4014     return;
4015   }
4016 
4017   for (const auto &GVI : valueIds()) {
4018     Stream.EmitRecord(bitc::FS_VALUE_GUID,
4019                       ArrayRef<uint64_t>{GVI.second, GVI.first});
4020   }
4021 
4022   // Abbrev for FS_PERMODULE_PROFILE.
4023   auto Abbv = std::make_shared<BitCodeAbbrev>();
4024   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_PROFILE));
4025   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4026   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4027   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4028   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4029   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4030   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4031   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4032   // numrefs x valueid, n x (valueid, hotness)
4033   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4034   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4035   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4036 
4037   // Abbrev for FS_PERMODULE or FS_PERMODULE_RELBF.
4038   Abbv = std::make_shared<BitCodeAbbrev>();
4039   if (WriteRelBFToSummary)
4040     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_RELBF));
4041   else
4042     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE));
4043   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4044   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4045   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4046   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4047   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4048   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4049   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4050   // numrefs x valueid, n x (valueid [, rel_block_freq])
4051   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4052   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4053   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4054 
4055   // Abbrev for FS_PERMODULE_GLOBALVAR_INIT_REFS.
4056   Abbv = std::make_shared<BitCodeAbbrev>();
4057   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS));
4058   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
4059   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
4060   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));  // valueids
4061   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4062   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4063 
4064   // Abbrev for FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS.
4065   Abbv = std::make_shared<BitCodeAbbrev>();
4066   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS));
4067   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
4068   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
4069   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numrefs
4070   // numrefs x valueid, n x (valueid , offset)
4071   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4072   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4073   unsigned FSModVTableRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4074 
4075   // Abbrev for FS_ALIAS.
4076   Abbv = std::make_shared<BitCodeAbbrev>();
4077   Abbv->Add(BitCodeAbbrevOp(bitc::FS_ALIAS));
4078   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4079   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4080   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4081   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4082 
4083   // Abbrev for FS_TYPE_ID_METADATA
4084   Abbv = std::make_shared<BitCodeAbbrev>();
4085   Abbv->Add(BitCodeAbbrevOp(bitc::FS_TYPE_ID_METADATA));
4086   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid strtab index
4087   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid length
4088   // n x (valueid , offset)
4089   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4090   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4091   unsigned TypeIdCompatibleVtableAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4092 
4093   SmallVector<uint64_t, 64> NameVals;
4094   // Iterate over the list of functions instead of the Index to
4095   // ensure the ordering is stable.
4096   for (const Function &F : M) {
4097     // Summary emission does not support anonymous functions, they have to
4098     // renamed using the anonymous function renaming pass.
4099     if (!F.hasName())
4100       report_fatal_error("Unexpected anonymous function when writing summary");
4101 
4102     ValueInfo VI = Index->getValueInfo(F.getGUID());
4103     if (!VI || VI.getSummaryList().empty()) {
4104       // Only declarations should not have a summary (a declaration might
4105       // however have a summary if the def was in module level asm).
4106       assert(F.isDeclaration());
4107       continue;
4108     }
4109     auto *Summary = VI.getSummaryList()[0].get();
4110     writePerModuleFunctionSummaryRecord(NameVals, Summary, VE.getValueID(&F),
4111                                         FSCallsAbbrev, FSCallsProfileAbbrev, F);
4112   }
4113 
4114   // Capture references from GlobalVariable initializers, which are outside
4115   // of a function scope.
4116   for (const GlobalVariable &G : M.globals())
4117     writeModuleLevelReferences(G, NameVals, FSModRefsAbbrev,
4118                                FSModVTableRefsAbbrev);
4119 
4120   for (const GlobalAlias &A : M.aliases()) {
4121     auto *Aliasee = A.getAliaseeObject();
4122     // Skip ifunc and nameless functions which don't have an entry in the
4123     // summary.
4124     if (!Aliasee->hasName() || isa<GlobalIFunc>(Aliasee))
4125       continue;
4126     auto AliasId = VE.getValueID(&A);
4127     auto AliaseeId = VE.getValueID(Aliasee);
4128     NameVals.push_back(AliasId);
4129     auto *Summary = Index->getGlobalValueSummary(A);
4130     AliasSummary *AS = cast<AliasSummary>(Summary);
4131     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
4132     NameVals.push_back(AliaseeId);
4133     Stream.EmitRecord(bitc::FS_ALIAS, NameVals, FSAliasAbbrev);
4134     NameVals.clear();
4135   }
4136 
4137   for (auto &S : Index->typeIdCompatibleVtableMap()) {
4138     writeTypeIdCompatibleVtableSummaryRecord(NameVals, StrtabBuilder, S.first,
4139                                              S.second, VE);
4140     Stream.EmitRecord(bitc::FS_TYPE_ID_METADATA, NameVals,
4141                       TypeIdCompatibleVtableAbbrev);
4142     NameVals.clear();
4143   }
4144 
4145   Stream.EmitRecord(bitc::FS_BLOCK_COUNT,
4146                     ArrayRef<uint64_t>{Index->getBlockCount()});
4147 
4148   Stream.ExitBlock();
4149 }
4150 
4151 /// Emit the combined summary section into the combined index file.
4152 void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
4153   Stream.EnterSubblock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID, 3);
4154   Stream.EmitRecord(
4155       bitc::FS_VERSION,
4156       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
4157 
4158   // Write the index flags.
4159   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Index.getFlags()});
4160 
4161   for (const auto &GVI : valueIds()) {
4162     Stream.EmitRecord(bitc::FS_VALUE_GUID,
4163                       ArrayRef<uint64_t>{GVI.second, GVI.first});
4164   }
4165 
4166   // Abbrev for FS_COMBINED.
4167   auto Abbv = std::make_shared<BitCodeAbbrev>();
4168   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED));
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)
4179   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4180   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4181   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4182 
4183   // Abbrev for FS_COMBINED_PROFILE.
4184   Abbv = std::make_shared<BitCodeAbbrev>();
4185   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_PROFILE));
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::VBR, 8));   // instcount
4190   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4191   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
4192   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4193   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4194   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4195   // numrefs x valueid, n x (valueid, hotness)
4196   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4197   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4198   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4199 
4200   // Abbrev for FS_COMBINED_GLOBALVAR_INIT_REFS.
4201   Abbv = std::make_shared<BitCodeAbbrev>();
4202   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS));
4203   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4204   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4205   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4206   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));    // valueids
4207   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4208   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4209 
4210   // Abbrev for FS_COMBINED_ALIAS.
4211   Abbv = std::make_shared<BitCodeAbbrev>();
4212   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_ALIAS));
4213   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4214   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4215   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4216   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4217   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4218 
4219   // The aliases are emitted as a post-pass, and will point to the value
4220   // id of the aliasee. Save them in a vector for post-processing.
4221   SmallVector<AliasSummary *, 64> Aliases;
4222 
4223   // Save the value id for each summary for alias emission.
4224   DenseMap<const GlobalValueSummary *, unsigned> SummaryToValueIdMap;
4225 
4226   SmallVector<uint64_t, 64> NameVals;
4227 
4228   // Set that will be populated during call to writeFunctionTypeMetadataRecords
4229   // with the type ids referenced by this index file.
4230   std::set<GlobalValue::GUID> ReferencedTypeIds;
4231 
4232   // For local linkage, we also emit the original name separately
4233   // immediately after the record.
4234   auto MaybeEmitOriginalName = [&](GlobalValueSummary &S) {
4235     // We don't need to emit the original name if we are writing the index for
4236     // distributed backends (in which case ModuleToSummariesForIndex is
4237     // non-null). The original name is only needed during the thin link, since
4238     // for SamplePGO the indirect call targets for local functions have
4239     // have the original name annotated in profile.
4240     // Continue to emit it when writing out the entire combined index, which is
4241     // used in testing the thin link via llvm-lto.
4242     if (ModuleToSummariesForIndex || !GlobalValue::isLocalLinkage(S.linkage()))
4243       return;
4244     NameVals.push_back(S.getOriginalName());
4245     Stream.EmitRecord(bitc::FS_COMBINED_ORIGINAL_NAME, NameVals);
4246     NameVals.clear();
4247   };
4248 
4249   std::set<GlobalValue::GUID> DefOrUseGUIDs;
4250   forEachSummary([&](GVInfo I, bool IsAliasee) {
4251     GlobalValueSummary *S = I.second;
4252     assert(S);
4253     DefOrUseGUIDs.insert(I.first);
4254     for (const ValueInfo &VI : S->refs())
4255       DefOrUseGUIDs.insert(VI.getGUID());
4256 
4257     auto ValueId = getValueId(I.first);
4258     assert(ValueId);
4259     SummaryToValueIdMap[S] = *ValueId;
4260 
4261     // If this is invoked for an aliasee, we want to record the above
4262     // mapping, but then not emit a summary entry (if the aliasee is
4263     // to be imported, we will invoke this separately with IsAliasee=false).
4264     if (IsAliasee)
4265       return;
4266 
4267     if (auto *AS = dyn_cast<AliasSummary>(S)) {
4268       // Will process aliases as a post-pass because the reader wants all
4269       // global to be loaded first.
4270       Aliases.push_back(AS);
4271       return;
4272     }
4273 
4274     if (auto *VS = dyn_cast<GlobalVarSummary>(S)) {
4275       NameVals.push_back(*ValueId);
4276       NameVals.push_back(Index.getModuleId(VS->modulePath()));
4277       NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
4278       NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
4279       for (auto &RI : VS->refs()) {
4280         auto RefValueId = getValueId(RI.getGUID());
4281         if (!RefValueId)
4282           continue;
4283         NameVals.push_back(*RefValueId);
4284       }
4285 
4286       // Emit the finished record.
4287       Stream.EmitRecord(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS, NameVals,
4288                         FSModRefsAbbrev);
4289       NameVals.clear();
4290       MaybeEmitOriginalName(*S);
4291       return;
4292     }
4293 
4294     auto GetValueId = [&](const ValueInfo &VI) -> Optional<unsigned> {
4295       return getValueId(VI.getGUID());
4296     };
4297 
4298     auto *FS = cast<FunctionSummary>(S);
4299     writeFunctionTypeMetadataRecords(Stream, FS, GetValueId);
4300     getReferencedTypeIds(FS, ReferencedTypeIds);
4301 
4302     NameVals.push_back(*ValueId);
4303     NameVals.push_back(Index.getModuleId(FS->modulePath()));
4304     NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
4305     NameVals.push_back(FS->instCount());
4306     NameVals.push_back(getEncodedFFlags(FS->fflags()));
4307     NameVals.push_back(FS->entryCount());
4308 
4309     // Fill in below
4310     NameVals.push_back(0); // numrefs
4311     NameVals.push_back(0); // rorefcnt
4312     NameVals.push_back(0); // worefcnt
4313 
4314     unsigned Count = 0, RORefCnt = 0, WORefCnt = 0;
4315     for (auto &RI : FS->refs()) {
4316       auto RefValueId = getValueId(RI.getGUID());
4317       if (!RefValueId)
4318         continue;
4319       NameVals.push_back(*RefValueId);
4320       if (RI.isReadOnly())
4321         RORefCnt++;
4322       else if (RI.isWriteOnly())
4323         WORefCnt++;
4324       Count++;
4325     }
4326     NameVals[6] = Count;
4327     NameVals[7] = RORefCnt;
4328     NameVals[8] = WORefCnt;
4329 
4330     bool HasProfileData = false;
4331     for (auto &EI : FS->calls()) {
4332       HasProfileData |=
4333           EI.second.getHotness() != CalleeInfo::HotnessType::Unknown;
4334       if (HasProfileData)
4335         break;
4336     }
4337 
4338     for (auto &EI : FS->calls()) {
4339       // If this GUID doesn't have a value id, it doesn't have a function
4340       // summary and we don't need to record any calls to it.
4341       Optional<unsigned> CallValueId = GetValueId(EI.first);
4342       if (!CallValueId)
4343         continue;
4344       NameVals.push_back(*CallValueId);
4345       if (HasProfileData)
4346         NameVals.push_back(static_cast<uint8_t>(EI.second.Hotness));
4347     }
4348 
4349     unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
4350     unsigned Code =
4351         (HasProfileData ? bitc::FS_COMBINED_PROFILE : bitc::FS_COMBINED);
4352 
4353     // Emit the finished record.
4354     Stream.EmitRecord(Code, NameVals, FSAbbrev);
4355     NameVals.clear();
4356     MaybeEmitOriginalName(*S);
4357   });
4358 
4359   for (auto *AS : Aliases) {
4360     auto AliasValueId = SummaryToValueIdMap[AS];
4361     assert(AliasValueId);
4362     NameVals.push_back(AliasValueId);
4363     NameVals.push_back(Index.getModuleId(AS->modulePath()));
4364     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
4365     auto AliaseeValueId = SummaryToValueIdMap[&AS->getAliasee()];
4366     assert(AliaseeValueId);
4367     NameVals.push_back(AliaseeValueId);
4368 
4369     // Emit the finished record.
4370     Stream.EmitRecord(bitc::FS_COMBINED_ALIAS, NameVals, FSAliasAbbrev);
4371     NameVals.clear();
4372     MaybeEmitOriginalName(*AS);
4373 
4374     if (auto *FS = dyn_cast<FunctionSummary>(&AS->getAliasee()))
4375       getReferencedTypeIds(FS, ReferencedTypeIds);
4376   }
4377 
4378   if (!Index.cfiFunctionDefs().empty()) {
4379     for (auto &S : Index.cfiFunctionDefs()) {
4380       if (DefOrUseGUIDs.count(
4381               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4382         NameVals.push_back(StrtabBuilder.add(S));
4383         NameVals.push_back(S.size());
4384       }
4385     }
4386     if (!NameVals.empty()) {
4387       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DEFS, NameVals);
4388       NameVals.clear();
4389     }
4390   }
4391 
4392   if (!Index.cfiFunctionDecls().empty()) {
4393     for (auto &S : Index.cfiFunctionDecls()) {
4394       if (DefOrUseGUIDs.count(
4395               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4396         NameVals.push_back(StrtabBuilder.add(S));
4397         NameVals.push_back(S.size());
4398       }
4399     }
4400     if (!NameVals.empty()) {
4401       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DECLS, NameVals);
4402       NameVals.clear();
4403     }
4404   }
4405 
4406   // Walk the GUIDs that were referenced, and write the
4407   // corresponding type id records.
4408   for (auto &T : ReferencedTypeIds) {
4409     auto TidIter = Index.typeIds().equal_range(T);
4410     for (auto It = TidIter.first; It != TidIter.second; ++It) {
4411       writeTypeIdSummaryRecord(NameVals, StrtabBuilder, It->second.first,
4412                                It->second.second);
4413       Stream.EmitRecord(bitc::FS_TYPE_ID, NameVals);
4414       NameVals.clear();
4415     }
4416   }
4417 
4418   Stream.EmitRecord(bitc::FS_BLOCK_COUNT,
4419                     ArrayRef<uint64_t>{Index.getBlockCount()});
4420 
4421   Stream.ExitBlock();
4422 }
4423 
4424 /// Create the "IDENTIFICATION_BLOCK_ID" containing a single string with the
4425 /// current llvm version, and a record for the epoch number.
4426 static void writeIdentificationBlock(BitstreamWriter &Stream) {
4427   Stream.EnterSubblock(bitc::IDENTIFICATION_BLOCK_ID, 5);
4428 
4429   // Write the "user readable" string identifying the bitcode producer
4430   auto Abbv = std::make_shared<BitCodeAbbrev>();
4431   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_STRING));
4432   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4433   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
4434   auto StringAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4435   writeStringRecord(Stream, bitc::IDENTIFICATION_CODE_STRING,
4436                     "LLVM" LLVM_VERSION_STRING, StringAbbrev);
4437 
4438   // Write the epoch version
4439   Abbv = std::make_shared<BitCodeAbbrev>();
4440   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_EPOCH));
4441   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
4442   auto EpochAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4443   constexpr std::array<unsigned, 1> Vals = {{bitc::BITCODE_CURRENT_EPOCH}};
4444   Stream.EmitRecord(bitc::IDENTIFICATION_CODE_EPOCH, Vals, EpochAbbrev);
4445   Stream.ExitBlock();
4446 }
4447 
4448 void ModuleBitcodeWriter::writeModuleHash(size_t BlockStartPos) {
4449   // Emit the module's hash.
4450   // MODULE_CODE_HASH: [5*i32]
4451   if (GenerateHash) {
4452     uint32_t Vals[5];
4453     Hasher.update(ArrayRef<uint8_t>((const uint8_t *)&(Buffer)[BlockStartPos],
4454                                     Buffer.size() - BlockStartPos));
4455     std::array<uint8_t, 20> Hash = Hasher.result();
4456     for (int Pos = 0; Pos < 20; Pos += 4) {
4457       Vals[Pos / 4] = support::endian::read32be(Hash.data() + Pos);
4458     }
4459 
4460     // Emit the finished record.
4461     Stream.EmitRecord(bitc::MODULE_CODE_HASH, Vals);
4462 
4463     if (ModHash)
4464       // Save the written hash value.
4465       llvm::copy(Vals, std::begin(*ModHash));
4466   }
4467 }
4468 
4469 void ModuleBitcodeWriter::write() {
4470   writeIdentificationBlock(Stream);
4471 
4472   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4473   size_t BlockStartPos = Buffer.size();
4474 
4475   writeModuleVersion();
4476 
4477   // Emit blockinfo, which defines the standard abbreviations etc.
4478   writeBlockInfo();
4479 
4480   // Emit information describing all of the types in the module.
4481   writeTypeTable();
4482 
4483   // Emit information about attribute groups.
4484   writeAttributeGroupTable();
4485 
4486   // Emit information about parameter attributes.
4487   writeAttributeTable();
4488 
4489   writeComdats();
4490 
4491   // Emit top-level description of module, including target triple, inline asm,
4492   // descriptors for global variables, and function prototype info.
4493   writeModuleInfo();
4494 
4495   // Emit constants.
4496   writeModuleConstants();
4497 
4498   // Emit metadata kind names.
4499   writeModuleMetadataKinds();
4500 
4501   // Emit metadata.
4502   writeModuleMetadata();
4503 
4504   // Emit module-level use-lists.
4505   if (VE.shouldPreserveUseListOrder())
4506     writeUseListBlock(nullptr);
4507 
4508   writeOperandBundleTags();
4509   writeSyncScopeNames();
4510 
4511   // Emit function bodies.
4512   DenseMap<const Function *, uint64_t> FunctionToBitcodeIndex;
4513   for (const Function &F : M)
4514     if (!F.isDeclaration())
4515       writeFunction(F, FunctionToBitcodeIndex);
4516 
4517   // Need to write after the above call to WriteFunction which populates
4518   // the summary information in the index.
4519   if (Index)
4520     writePerModuleGlobalValueSummary();
4521 
4522   writeGlobalValueSymbolTable(FunctionToBitcodeIndex);
4523 
4524   writeModuleHash(BlockStartPos);
4525 
4526   Stream.ExitBlock();
4527 }
4528 
4529 static void writeInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
4530                                uint32_t &Position) {
4531   support::endian::write32le(&Buffer[Position], Value);
4532   Position += 4;
4533 }
4534 
4535 /// If generating a bc file on darwin, we have to emit a
4536 /// header and trailer to make it compatible with the system archiver.  To do
4537 /// this we emit the following header, and then emit a trailer that pads the
4538 /// file out to be a multiple of 16 bytes.
4539 ///
4540 /// struct bc_header {
4541 ///   uint32_t Magic;         // 0x0B17C0DE
4542 ///   uint32_t Version;       // Version, currently always 0.
4543 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
4544 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
4545 ///   uint32_t CPUType;       // CPU specifier.
4546 ///   ... potentially more later ...
4547 /// };
4548 static void emitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
4549                                          const Triple &TT) {
4550   unsigned CPUType = ~0U;
4551 
4552   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
4553   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
4554   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
4555   // specific constants here because they are implicitly part of the Darwin ABI.
4556   enum {
4557     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
4558     DARWIN_CPU_TYPE_X86        = 7,
4559     DARWIN_CPU_TYPE_ARM        = 12,
4560     DARWIN_CPU_TYPE_POWERPC    = 18
4561   };
4562 
4563   Triple::ArchType Arch = TT.getArch();
4564   if (Arch == Triple::x86_64)
4565     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
4566   else if (Arch == Triple::x86)
4567     CPUType = DARWIN_CPU_TYPE_X86;
4568   else if (Arch == Triple::ppc)
4569     CPUType = DARWIN_CPU_TYPE_POWERPC;
4570   else if (Arch == Triple::ppc64)
4571     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
4572   else if (Arch == Triple::arm || Arch == Triple::thumb)
4573     CPUType = DARWIN_CPU_TYPE_ARM;
4574 
4575   // Traditional Bitcode starts after header.
4576   assert(Buffer.size() >= BWH_HeaderSize &&
4577          "Expected header size to be reserved");
4578   unsigned BCOffset = BWH_HeaderSize;
4579   unsigned BCSize = Buffer.size() - BWH_HeaderSize;
4580 
4581   // Write the magic and version.
4582   unsigned Position = 0;
4583   writeInt32ToBuffer(0x0B17C0DE, Buffer, Position);
4584   writeInt32ToBuffer(0, Buffer, Position); // Version.
4585   writeInt32ToBuffer(BCOffset, Buffer, Position);
4586   writeInt32ToBuffer(BCSize, Buffer, Position);
4587   writeInt32ToBuffer(CPUType, Buffer, Position);
4588 
4589   // If the file is not a multiple of 16 bytes, insert dummy padding.
4590   while (Buffer.size() & 15)
4591     Buffer.push_back(0);
4592 }
4593 
4594 /// Helper to write the header common to all bitcode files.
4595 static void writeBitcodeHeader(BitstreamWriter &Stream) {
4596   // Emit the file header.
4597   Stream.Emit((unsigned)'B', 8);
4598   Stream.Emit((unsigned)'C', 8);
4599   Stream.Emit(0x0, 4);
4600   Stream.Emit(0xC, 4);
4601   Stream.Emit(0xE, 4);
4602   Stream.Emit(0xD, 4);
4603 }
4604 
4605 BitcodeWriter::BitcodeWriter(SmallVectorImpl<char> &Buffer, raw_fd_stream *FS)
4606     : Buffer(Buffer), Stream(new BitstreamWriter(Buffer, FS, FlushThreshold)) {
4607   writeBitcodeHeader(*Stream);
4608 }
4609 
4610 BitcodeWriter::~BitcodeWriter() { assert(WroteStrtab); }
4611 
4612 void BitcodeWriter::writeBlob(unsigned Block, unsigned Record, StringRef Blob) {
4613   Stream->EnterSubblock(Block, 3);
4614 
4615   auto Abbv = std::make_shared<BitCodeAbbrev>();
4616   Abbv->Add(BitCodeAbbrevOp(Record));
4617   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
4618   auto AbbrevNo = Stream->EmitAbbrev(std::move(Abbv));
4619 
4620   Stream->EmitRecordWithBlob(AbbrevNo, ArrayRef<uint64_t>{Record}, Blob);
4621 
4622   Stream->ExitBlock();
4623 }
4624 
4625 void BitcodeWriter::writeSymtab() {
4626   assert(!WroteStrtab && !WroteSymtab);
4627 
4628   // If any module has module-level inline asm, we will require a registered asm
4629   // parser for the target so that we can create an accurate symbol table for
4630   // the module.
4631   for (Module *M : Mods) {
4632     if (M->getModuleInlineAsm().empty())
4633       continue;
4634 
4635     std::string Err;
4636     const Triple TT(M->getTargetTriple());
4637     const Target *T = TargetRegistry::lookupTarget(TT.str(), Err);
4638     if (!T || !T->hasMCAsmParser())
4639       return;
4640   }
4641 
4642   WroteSymtab = true;
4643   SmallVector<char, 0> Symtab;
4644   // The irsymtab::build function may be unable to create a symbol table if the
4645   // module is malformed (e.g. it contains an invalid alias). Writing a symbol
4646   // table is not required for correctness, but we still want to be able to
4647   // write malformed modules to bitcode files, so swallow the error.
4648   if (Error E = irsymtab::build(Mods, Symtab, StrtabBuilder, Alloc)) {
4649     consumeError(std::move(E));
4650     return;
4651   }
4652 
4653   writeBlob(bitc::SYMTAB_BLOCK_ID, bitc::SYMTAB_BLOB,
4654             {Symtab.data(), Symtab.size()});
4655 }
4656 
4657 void BitcodeWriter::writeStrtab() {
4658   assert(!WroteStrtab);
4659 
4660   std::vector<char> Strtab;
4661   StrtabBuilder.finalizeInOrder();
4662   Strtab.resize(StrtabBuilder.getSize());
4663   StrtabBuilder.write((uint8_t *)Strtab.data());
4664 
4665   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB,
4666             {Strtab.data(), Strtab.size()});
4667 
4668   WroteStrtab = true;
4669 }
4670 
4671 void BitcodeWriter::copyStrtab(StringRef Strtab) {
4672   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB, Strtab);
4673   WroteStrtab = true;
4674 }
4675 
4676 void BitcodeWriter::writeModule(const Module &M,
4677                                 bool ShouldPreserveUseListOrder,
4678                                 const ModuleSummaryIndex *Index,
4679                                 bool GenerateHash, ModuleHash *ModHash) {
4680   assert(!WroteStrtab);
4681 
4682   // The Mods vector is used by irsymtab::build, which requires non-const
4683   // Modules in case it needs to materialize metadata. But the bitcode writer
4684   // requires that the module is materialized, so we can cast to non-const here,
4685   // after checking that it is in fact materialized.
4686   assert(M.isMaterialized());
4687   Mods.push_back(const_cast<Module *>(&M));
4688 
4689   ModuleBitcodeWriter ModuleWriter(M, Buffer, StrtabBuilder, *Stream,
4690                                    ShouldPreserveUseListOrder, Index,
4691                                    GenerateHash, ModHash);
4692   ModuleWriter.write();
4693 }
4694 
4695 void BitcodeWriter::writeIndex(
4696     const ModuleSummaryIndex *Index,
4697     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4698   IndexBitcodeWriter IndexWriter(*Stream, StrtabBuilder, *Index,
4699                                  ModuleToSummariesForIndex);
4700   IndexWriter.write();
4701 }
4702 
4703 /// Write the specified module to the specified output stream.
4704 void llvm::WriteBitcodeToFile(const Module &M, raw_ostream &Out,
4705                               bool ShouldPreserveUseListOrder,
4706                               const ModuleSummaryIndex *Index,
4707                               bool GenerateHash, ModuleHash *ModHash) {
4708   SmallVector<char, 0> Buffer;
4709   Buffer.reserve(256*1024);
4710 
4711   // If this is darwin or another generic macho target, reserve space for the
4712   // header.
4713   Triple TT(M.getTargetTriple());
4714   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4715     Buffer.insert(Buffer.begin(), BWH_HeaderSize, 0);
4716 
4717   BitcodeWriter Writer(Buffer, dyn_cast<raw_fd_stream>(&Out));
4718   Writer.writeModule(M, ShouldPreserveUseListOrder, Index, GenerateHash,
4719                      ModHash);
4720   Writer.writeSymtab();
4721   Writer.writeStrtab();
4722 
4723   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4724     emitDarwinBCHeaderAndTrailer(Buffer, TT);
4725 
4726   // Write the generated bitstream to "Out".
4727   if (!Buffer.empty())
4728     Out.write((char *)&Buffer.front(), Buffer.size());
4729 }
4730 
4731 void IndexBitcodeWriter::write() {
4732   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4733 
4734   writeModuleVersion();
4735 
4736   // Write the module paths in the combined index.
4737   writeModStrings();
4738 
4739   // Write the summary combined index records.
4740   writeCombinedGlobalValueSummary();
4741 
4742   Stream.ExitBlock();
4743 }
4744 
4745 // Write the specified module summary index to the given raw output stream,
4746 // where it will be written in a new bitcode block. This is used when
4747 // writing the combined index file for ThinLTO. When writing a subset of the
4748 // index for a distributed backend, provide a \p ModuleToSummariesForIndex map.
4749 void llvm::writeIndexToFile(
4750     const ModuleSummaryIndex &Index, raw_ostream &Out,
4751     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4752   SmallVector<char, 0> Buffer;
4753   Buffer.reserve(256 * 1024);
4754 
4755   BitcodeWriter Writer(Buffer);
4756   Writer.writeIndex(&Index, ModuleToSummariesForIndex);
4757   Writer.writeStrtab();
4758 
4759   Out.write((char *)&Buffer.front(), Buffer.size());
4760 }
4761 
4762 namespace {
4763 
4764 /// Class to manage the bitcode writing for a thin link bitcode file.
4765 class ThinLinkBitcodeWriter : public ModuleBitcodeWriterBase {
4766   /// ModHash is for use in ThinLTO incremental build, generated while writing
4767   /// the module bitcode file.
4768   const ModuleHash *ModHash;
4769 
4770 public:
4771   ThinLinkBitcodeWriter(const Module &M, StringTableBuilder &StrtabBuilder,
4772                         BitstreamWriter &Stream,
4773                         const ModuleSummaryIndex &Index,
4774                         const ModuleHash &ModHash)
4775       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
4776                                 /*ShouldPreserveUseListOrder=*/false, &Index),
4777         ModHash(&ModHash) {}
4778 
4779   void write();
4780 
4781 private:
4782   void writeSimplifiedModuleInfo();
4783 };
4784 
4785 } // end anonymous namespace
4786 
4787 // This function writes a simpilified module info for thin link bitcode file.
4788 // It only contains the source file name along with the name(the offset and
4789 // size in strtab) and linkage for global values. For the global value info
4790 // entry, in order to keep linkage at offset 5, there are three zeros used
4791 // as padding.
4792 void ThinLinkBitcodeWriter::writeSimplifiedModuleInfo() {
4793   SmallVector<unsigned, 64> Vals;
4794   // Emit the module's source file name.
4795   {
4796     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
4797     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
4798     if (Bits == SE_Char6)
4799       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
4800     else if (Bits == SE_Fixed7)
4801       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
4802 
4803     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
4804     auto Abbv = std::make_shared<BitCodeAbbrev>();
4805     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
4806     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4807     Abbv->Add(AbbrevOpToUse);
4808     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4809 
4810     for (const auto P : M.getSourceFileName())
4811       Vals.push_back((unsigned char)P);
4812 
4813     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
4814     Vals.clear();
4815   }
4816 
4817   // Emit the global variable information.
4818   for (const GlobalVariable &GV : M.globals()) {
4819     // GLOBALVAR: [strtab offset, strtab size, 0, 0, 0, linkage]
4820     Vals.push_back(StrtabBuilder.add(GV.getName()));
4821     Vals.push_back(GV.getName().size());
4822     Vals.push_back(0);
4823     Vals.push_back(0);
4824     Vals.push_back(0);
4825     Vals.push_back(getEncodedLinkage(GV));
4826 
4827     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals);
4828     Vals.clear();
4829   }
4830 
4831   // Emit the function proto information.
4832   for (const Function &F : M) {
4833     // FUNCTION:  [strtab offset, strtab size, 0, 0, 0, linkage]
4834     Vals.push_back(StrtabBuilder.add(F.getName()));
4835     Vals.push_back(F.getName().size());
4836     Vals.push_back(0);
4837     Vals.push_back(0);
4838     Vals.push_back(0);
4839     Vals.push_back(getEncodedLinkage(F));
4840 
4841     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals);
4842     Vals.clear();
4843   }
4844 
4845   // Emit the alias information.
4846   for (const GlobalAlias &A : M.aliases()) {
4847     // ALIAS: [strtab offset, strtab size, 0, 0, 0, linkage]
4848     Vals.push_back(StrtabBuilder.add(A.getName()));
4849     Vals.push_back(A.getName().size());
4850     Vals.push_back(0);
4851     Vals.push_back(0);
4852     Vals.push_back(0);
4853     Vals.push_back(getEncodedLinkage(A));
4854 
4855     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals);
4856     Vals.clear();
4857   }
4858 
4859   // Emit the ifunc information.
4860   for (const GlobalIFunc &I : M.ifuncs()) {
4861     // IFUNC: [strtab offset, strtab size, 0, 0, 0, linkage]
4862     Vals.push_back(StrtabBuilder.add(I.getName()));
4863     Vals.push_back(I.getName().size());
4864     Vals.push_back(0);
4865     Vals.push_back(0);
4866     Vals.push_back(0);
4867     Vals.push_back(getEncodedLinkage(I));
4868 
4869     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
4870     Vals.clear();
4871   }
4872 }
4873 
4874 void ThinLinkBitcodeWriter::write() {
4875   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4876 
4877   writeModuleVersion();
4878 
4879   writeSimplifiedModuleInfo();
4880 
4881   writePerModuleGlobalValueSummary();
4882 
4883   // Write module hash.
4884   Stream.EmitRecord(bitc::MODULE_CODE_HASH, ArrayRef<uint32_t>(*ModHash));
4885 
4886   Stream.ExitBlock();
4887 }
4888 
4889 void BitcodeWriter::writeThinLinkBitcode(const Module &M,
4890                                          const ModuleSummaryIndex &Index,
4891                                          const ModuleHash &ModHash) {
4892   assert(!WroteStrtab);
4893 
4894   // The Mods vector is used by irsymtab::build, which requires non-const
4895   // Modules in case it needs to materialize metadata. But the bitcode writer
4896   // requires that the module is materialized, so we can cast to non-const here,
4897   // after checking that it is in fact materialized.
4898   assert(M.isMaterialized());
4899   Mods.push_back(const_cast<Module *>(&M));
4900 
4901   ThinLinkBitcodeWriter ThinLinkWriter(M, StrtabBuilder, *Stream, Index,
4902                                        ModHash);
4903   ThinLinkWriter.write();
4904 }
4905 
4906 // Write the specified thin link bitcode file to the given raw output stream,
4907 // where it will be written in a new bitcode block. This is used when
4908 // writing the per-module index file for ThinLTO.
4909 void llvm::writeThinLinkBitcodeToFile(const Module &M, raw_ostream &Out,
4910                                       const ModuleSummaryIndex &Index,
4911                                       const ModuleHash &ModHash) {
4912   SmallVector<char, 0> Buffer;
4913   Buffer.reserve(256 * 1024);
4914 
4915   BitcodeWriter Writer(Buffer);
4916   Writer.writeThinLinkBitcode(M, Index, ModHash);
4917   Writer.writeSymtab();
4918   Writer.writeStrtab();
4919 
4920   Out.write((char *)&Buffer.front(), Buffer.size());
4921 }
4922 
4923 static const char *getSectionNameForBitcode(const Triple &T) {
4924   switch (T.getObjectFormat()) {
4925   case Triple::MachO:
4926     return "__LLVM,__bitcode";
4927   case Triple::COFF:
4928   case Triple::ELF:
4929   case Triple::Wasm:
4930   case Triple::UnknownObjectFormat:
4931     return ".llvmbc";
4932   case Triple::GOFF:
4933     llvm_unreachable("GOFF is not yet implemented");
4934     break;
4935   case Triple::SPIRV:
4936     llvm_unreachable("SPIRV is not yet implemented");
4937     break;
4938   case Triple::XCOFF:
4939     llvm_unreachable("XCOFF is not yet implemented");
4940     break;
4941   case Triple::DXContainer:
4942     llvm_unreachable("DXContainer is not yet implemented");
4943     break;
4944   }
4945   llvm_unreachable("Unimplemented ObjectFormatType");
4946 }
4947 
4948 static const char *getSectionNameForCommandline(const Triple &T) {
4949   switch (T.getObjectFormat()) {
4950   case Triple::MachO:
4951     return "__LLVM,__cmdline";
4952   case Triple::COFF:
4953   case Triple::ELF:
4954   case Triple::Wasm:
4955   case Triple::UnknownObjectFormat:
4956     return ".llvmcmd";
4957   case Triple::GOFF:
4958     llvm_unreachable("GOFF is not yet implemented");
4959     break;
4960   case Triple::SPIRV:
4961     llvm_unreachable("SPIRV is not yet implemented");
4962     break;
4963   case Triple::XCOFF:
4964     llvm_unreachable("XCOFF is not yet implemented");
4965     break;
4966   case Triple::DXContainer:
4967     llvm_unreachable("DXC is not yet implemented");
4968     break;
4969   }
4970   llvm_unreachable("Unimplemented ObjectFormatType");
4971 }
4972 
4973 void llvm::embedBitcodeInModule(llvm::Module &M, llvm::MemoryBufferRef Buf,
4974                                 bool EmbedBitcode, bool EmbedCmdline,
4975                                 const std::vector<uint8_t> &CmdArgs) {
4976   // Save llvm.compiler.used and remove it.
4977   SmallVector<Constant *, 2> UsedArray;
4978   SmallVector<GlobalValue *, 4> UsedGlobals;
4979   Type *UsedElementType = Type::getInt8Ty(M.getContext())->getPointerTo(0);
4980   GlobalVariable *Used = collectUsedGlobalVariables(M, UsedGlobals, true);
4981   for (auto *GV : UsedGlobals) {
4982     if (GV->getName() != "llvm.embedded.module" &&
4983         GV->getName() != "llvm.cmdline")
4984       UsedArray.push_back(
4985           ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
4986   }
4987   if (Used)
4988     Used->eraseFromParent();
4989 
4990   // Embed the bitcode for the llvm module.
4991   std::string Data;
4992   ArrayRef<uint8_t> ModuleData;
4993   Triple T(M.getTargetTriple());
4994 
4995   if (EmbedBitcode) {
4996     if (Buf.getBufferSize() == 0 ||
4997         !isBitcode((const unsigned char *)Buf.getBufferStart(),
4998                    (const unsigned char *)Buf.getBufferEnd())) {
4999       // If the input is LLVM Assembly, bitcode is produced by serializing
5000       // the module. Use-lists order need to be preserved in this case.
5001       llvm::raw_string_ostream OS(Data);
5002       llvm::WriteBitcodeToFile(M, OS, /* ShouldPreserveUseListOrder */ true);
5003       ModuleData =
5004           ArrayRef<uint8_t>((const uint8_t *)OS.str().data(), OS.str().size());
5005     } else
5006       // If the input is LLVM bitcode, write the input byte stream directly.
5007       ModuleData = ArrayRef<uint8_t>((const uint8_t *)Buf.getBufferStart(),
5008                                      Buf.getBufferSize());
5009   }
5010   llvm::Constant *ModuleConstant =
5011       llvm::ConstantDataArray::get(M.getContext(), ModuleData);
5012   llvm::GlobalVariable *GV = new llvm::GlobalVariable(
5013       M, ModuleConstant->getType(), true, llvm::GlobalValue::PrivateLinkage,
5014       ModuleConstant);
5015   GV->setSection(getSectionNameForBitcode(T));
5016   // Set alignment to 1 to prevent padding between two contributions from input
5017   // sections after linking.
5018   GV->setAlignment(Align(1));
5019   UsedArray.push_back(
5020       ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
5021   if (llvm::GlobalVariable *Old =
5022           M.getGlobalVariable("llvm.embedded.module", true)) {
5023     assert(Old->hasZeroLiveUses() &&
5024            "llvm.embedded.module can only be used once in llvm.compiler.used");
5025     GV->takeName(Old);
5026     Old->eraseFromParent();
5027   } else {
5028     GV->setName("llvm.embedded.module");
5029   }
5030 
5031   // Skip if only bitcode needs to be embedded.
5032   if (EmbedCmdline) {
5033     // Embed command-line options.
5034     ArrayRef<uint8_t> CmdData(const_cast<uint8_t *>(CmdArgs.data()),
5035                               CmdArgs.size());
5036     llvm::Constant *CmdConstant =
5037         llvm::ConstantDataArray::get(M.getContext(), CmdData);
5038     GV = new llvm::GlobalVariable(M, CmdConstant->getType(), true,
5039                                   llvm::GlobalValue::PrivateLinkage,
5040                                   CmdConstant);
5041     GV->setSection(getSectionNameForCommandline(T));
5042     GV->setAlignment(Align(1));
5043     UsedArray.push_back(
5044         ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
5045     if (llvm::GlobalVariable *Old = M.getGlobalVariable("llvm.cmdline", true)) {
5046       assert(Old->hasZeroLiveUses() &&
5047              "llvm.cmdline can only be used once in llvm.compiler.used");
5048       GV->takeName(Old);
5049       Old->eraseFromParent();
5050     } else {
5051       GV->setName("llvm.cmdline");
5052     }
5053   }
5054 
5055   if (UsedArray.empty())
5056     return;
5057 
5058   // Recreate llvm.compiler.used.
5059   ArrayType *ATy = ArrayType::get(UsedElementType, UsedArray.size());
5060   auto *NewUsed = new GlobalVariable(
5061       M, ATy, false, llvm::GlobalValue::AppendingLinkage,
5062       llvm::ConstantArray::get(ATy, UsedArray), "llvm.compiler.used");
5063   NewUsed->setSection("llvm.metadata");
5064 }
5065