xref: /llvm-project/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp (revision 23ec5782c3cc0d77b5e44285e5124cd4a3ffeeef)
1 //===- Bitcode/Writer/BitcodeWriter.cpp - Bitcode Writer ------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // Bitcode writer implementation.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "llvm/Bitcode/BitcodeWriter.h"
14 #include "ValueEnumerator.h"
15 #include "llvm/ADT/APFloat.h"
16 #include "llvm/ADT/APInt.h"
17 #include "llvm/ADT/ArrayRef.h"
18 #include "llvm/ADT/DenseMap.h"
19 #include "llvm/ADT/None.h"
20 #include "llvm/ADT/Optional.h"
21 #include "llvm/ADT/STLExtras.h"
22 #include "llvm/ADT/SmallPtrSet.h"
23 #include "llvm/ADT/SmallString.h"
24 #include "llvm/ADT/SmallVector.h"
25 #include "llvm/ADT/StringMap.h"
26 #include "llvm/ADT/StringRef.h"
27 #include "llvm/ADT/Triple.h"
28 #include "llvm/Bitcode/BitcodeCommon.h"
29 #include "llvm/Bitcode/BitcodeReader.h"
30 #include "llvm/Bitcode/LLVMBitCodes.h"
31 #include "llvm/Bitstream/BitCodes.h"
32 #include "llvm/Bitstream/BitstreamWriter.h"
33 #include "llvm/Config/llvm-config.h"
34 #include "llvm/IR/Attributes.h"
35 #include "llvm/IR/BasicBlock.h"
36 #include "llvm/IR/Comdat.h"
37 #include "llvm/IR/Constant.h"
38 #include "llvm/IR/Constants.h"
39 #include "llvm/IR/DebugInfoMetadata.h"
40 #include "llvm/IR/DebugLoc.h"
41 #include "llvm/IR/DerivedTypes.h"
42 #include "llvm/IR/Function.h"
43 #include "llvm/IR/GlobalAlias.h"
44 #include "llvm/IR/GlobalIFunc.h"
45 #include "llvm/IR/GlobalObject.h"
46 #include "llvm/IR/GlobalValue.h"
47 #include "llvm/IR/GlobalVariable.h"
48 #include "llvm/IR/InlineAsm.h"
49 #include "llvm/IR/InstrTypes.h"
50 #include "llvm/IR/Instruction.h"
51 #include "llvm/IR/Instructions.h"
52 #include "llvm/IR/LLVMContext.h"
53 #include "llvm/IR/Metadata.h"
54 #include "llvm/IR/Module.h"
55 #include "llvm/IR/ModuleSummaryIndex.h"
56 #include "llvm/IR/Operator.h"
57 #include "llvm/IR/Type.h"
58 #include "llvm/IR/UseListOrder.h"
59 #include "llvm/IR/Value.h"
60 #include "llvm/IR/ValueSymbolTable.h"
61 #include "llvm/MC/StringTableBuilder.h"
62 #include "llvm/MC/TargetRegistry.h"
63 #include "llvm/Object/IRSymtab.h"
64 #include "llvm/Support/AtomicOrdering.h"
65 #include "llvm/Support/Casting.h"
66 #include "llvm/Support/CommandLine.h"
67 #include "llvm/Support/Endian.h"
68 #include "llvm/Support/Error.h"
69 #include "llvm/Support/ErrorHandling.h"
70 #include "llvm/Support/MathExtras.h"
71 #include "llvm/Support/SHA1.h"
72 #include "llvm/Support/raw_ostream.h"
73 #include <algorithm>
74 #include <cassert>
75 #include <cstddef>
76 #include <cstdint>
77 #include <iterator>
78 #include <map>
79 #include <memory>
80 #include <string>
81 #include <utility>
82 #include <vector>
83 
84 using namespace llvm;
85 
86 static cl::opt<unsigned>
87     IndexThreshold("bitcode-mdindex-threshold", cl::Hidden, cl::init(25),
88                    cl::desc("Number of metadatas above which we emit an index "
89                             "to enable lazy-loading"));
90 static cl::opt<uint32_t> FlushThreshold(
91     "bitcode-flush-threshold", cl::Hidden, cl::init(512),
92     cl::desc("The threshold (unit M) for flushing LLVM bitcode."));
93 
94 static cl::opt<bool> WriteRelBFToSummary(
95     "write-relbf-to-summary", cl::Hidden, cl::init(false),
96     cl::desc("Write relative block frequency to function summary "));
97 
98 extern FunctionSummary::ForceSummaryHotnessType ForceSummaryEdgesCold;
99 
100 namespace {
101 
102 /// These are manifest constants used by the bitcode writer. They do not need to
103 /// be kept in sync with the reader, but need to be consistent within this file.
104 enum {
105   // VALUE_SYMTAB_BLOCK abbrev id's.
106   VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
107   VST_ENTRY_7_ABBREV,
108   VST_ENTRY_6_ABBREV,
109   VST_BBENTRY_6_ABBREV,
110 
111   // CONSTANTS_BLOCK abbrev id's.
112   CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
113   CONSTANTS_INTEGER_ABBREV,
114   CONSTANTS_CE_CAST_Abbrev,
115   CONSTANTS_NULL_Abbrev,
116 
117   // FUNCTION_BLOCK abbrev id's.
118   FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
119   FUNCTION_INST_UNOP_ABBREV,
120   FUNCTION_INST_UNOP_FLAGS_ABBREV,
121   FUNCTION_INST_BINOP_ABBREV,
122   FUNCTION_INST_BINOP_FLAGS_ABBREV,
123   FUNCTION_INST_CAST_ABBREV,
124   FUNCTION_INST_RET_VOID_ABBREV,
125   FUNCTION_INST_RET_VAL_ABBREV,
126   FUNCTION_INST_UNREACHABLE_ABBREV,
127   FUNCTION_INST_GEP_ABBREV,
128 };
129 
130 /// Abstract class to manage the bitcode writing, subclassed for each bitcode
131 /// file type.
132 class BitcodeWriterBase {
133 protected:
134   /// The stream created and owned by the client.
135   BitstreamWriter &Stream;
136 
137   StringTableBuilder &StrtabBuilder;
138 
139 public:
140   /// Constructs a BitcodeWriterBase object that writes to the provided
141   /// \p Stream.
142   BitcodeWriterBase(BitstreamWriter &Stream, StringTableBuilder &StrtabBuilder)
143       : Stream(Stream), StrtabBuilder(StrtabBuilder) {}
144 
145 protected:
146   void writeModuleVersion();
147 };
148 
149 void BitcodeWriterBase::writeModuleVersion() {
150   // VERSION: [version#]
151   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, ArrayRef<uint64_t>{2});
152 }
153 
154 /// Base class to manage the module bitcode writing, currently subclassed for
155 /// ModuleBitcodeWriter and ThinLinkBitcodeWriter.
156 class ModuleBitcodeWriterBase : public BitcodeWriterBase {
157 protected:
158   /// The Module to write to bitcode.
159   const Module &M;
160 
161   /// Enumerates ids for all values in the module.
162   ValueEnumerator VE;
163 
164   /// Optional per-module index to write for ThinLTO.
165   const ModuleSummaryIndex *Index;
166 
167   /// Map that holds the correspondence between GUIDs in the summary index,
168   /// that came from indirect call profiles, and a value id generated by this
169   /// class to use in the VST and summary block records.
170   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
171 
172   /// Tracks the last value id recorded in the GUIDToValueMap.
173   unsigned GlobalValueId;
174 
175   /// Saves the offset of the VSTOffset record that must eventually be
176   /// backpatched with the offset of the actual VST.
177   uint64_t VSTOffsetPlaceholder = 0;
178 
179 public:
180   /// Constructs a ModuleBitcodeWriterBase object for the given Module,
181   /// writing to the provided \p Buffer.
182   ModuleBitcodeWriterBase(const Module &M, StringTableBuilder &StrtabBuilder,
183                           BitstreamWriter &Stream,
184                           bool ShouldPreserveUseListOrder,
185                           const ModuleSummaryIndex *Index)
186       : BitcodeWriterBase(Stream, StrtabBuilder), M(M),
187         VE(M, ShouldPreserveUseListOrder), Index(Index) {
188     // Assign ValueIds to any callee values in the index that came from
189     // indirect call profiles and were recorded as a GUID not a Value*
190     // (which would have been assigned an ID by the ValueEnumerator).
191     // The starting ValueId is just after the number of values in the
192     // ValueEnumerator, so that they can be emitted in the VST.
193     GlobalValueId = VE.getValues().size();
194     if (!Index)
195       return;
196     for (const auto &GUIDSummaryLists : *Index)
197       // Examine all summaries for this GUID.
198       for (auto &Summary : GUIDSummaryLists.second.SummaryList)
199         if (auto FS = dyn_cast<FunctionSummary>(Summary.get()))
200           // For each call in the function summary, see if the call
201           // is to a GUID (which means it is for an indirect call,
202           // otherwise we would have a Value for it). If so, synthesize
203           // a value id.
204           for (auto &CallEdge : FS->calls())
205             if (!CallEdge.first.haveGVs() || !CallEdge.first.getValue())
206               assignValueId(CallEdge.first.getGUID());
207   }
208 
209 protected:
210   void writePerModuleGlobalValueSummary();
211 
212 private:
213   void writePerModuleFunctionSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
214                                            GlobalValueSummary *Summary,
215                                            unsigned ValueID,
216                                            unsigned FSCallsAbbrev,
217                                            unsigned FSCallsProfileAbbrev,
218                                            const Function &F);
219   void writeModuleLevelReferences(const GlobalVariable &V,
220                                   SmallVector<uint64_t, 64> &NameVals,
221                                   unsigned FSModRefsAbbrev,
222                                   unsigned FSModVTableRefsAbbrev);
223 
224   void assignValueId(GlobalValue::GUID ValGUID) {
225     GUIDToValueIdMap[ValGUID] = ++GlobalValueId;
226   }
227 
228   unsigned getValueId(GlobalValue::GUID ValGUID) {
229     const auto &VMI = GUIDToValueIdMap.find(ValGUID);
230     // Expect that any GUID value had a value Id assigned by an
231     // earlier call to assignValueId.
232     assert(VMI != GUIDToValueIdMap.end() &&
233            "GUID does not have assigned value Id");
234     return VMI->second;
235   }
236 
237   // Helper to get the valueId for the type of value recorded in VI.
238   unsigned getValueId(ValueInfo VI) {
239     if (!VI.haveGVs() || !VI.getValue())
240       return getValueId(VI.getGUID());
241     return VE.getValueID(VI.getValue());
242   }
243 
244   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
245 };
246 
247 /// Class to manage the bitcode writing for a module.
248 class ModuleBitcodeWriter : public ModuleBitcodeWriterBase {
249   /// Pointer to the buffer allocated by caller for bitcode writing.
250   const SmallVectorImpl<char> &Buffer;
251 
252   /// True if a module hash record should be written.
253   bool GenerateHash;
254 
255   /// If non-null, when GenerateHash is true, the resulting hash is written
256   /// into ModHash.
257   ModuleHash *ModHash;
258 
259   SHA1 Hasher;
260 
261   /// The start bit of the identification block.
262   uint64_t BitcodeStartBit;
263 
264 public:
265   /// Constructs a ModuleBitcodeWriter object for the given Module,
266   /// writing to the provided \p Buffer.
267   ModuleBitcodeWriter(const Module &M, SmallVectorImpl<char> &Buffer,
268                       StringTableBuilder &StrtabBuilder,
269                       BitstreamWriter &Stream, bool ShouldPreserveUseListOrder,
270                       const ModuleSummaryIndex *Index, bool GenerateHash,
271                       ModuleHash *ModHash = nullptr)
272       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
273                                 ShouldPreserveUseListOrder, Index),
274         Buffer(Buffer), GenerateHash(GenerateHash), ModHash(ModHash),
275         BitcodeStartBit(Stream.GetCurrentBitNo()) {}
276 
277   /// Emit the current module to the bitstream.
278   void write();
279 
280 private:
281   uint64_t bitcodeStartBit() { return BitcodeStartBit; }
282 
283   size_t addToStrtab(StringRef Str);
284 
285   void writeAttributeGroupTable();
286   void writeAttributeTable();
287   void writeTypeTable();
288   void writeComdats();
289   void writeValueSymbolTableForwardDecl();
290   void writeModuleInfo();
291   void writeValueAsMetadata(const ValueAsMetadata *MD,
292                             SmallVectorImpl<uint64_t> &Record);
293   void writeMDTuple(const MDTuple *N, SmallVectorImpl<uint64_t> &Record,
294                     unsigned Abbrev);
295   unsigned createDILocationAbbrev();
296   void writeDILocation(const DILocation *N, SmallVectorImpl<uint64_t> &Record,
297                        unsigned &Abbrev);
298   unsigned createGenericDINodeAbbrev();
299   void writeGenericDINode(const GenericDINode *N,
300                           SmallVectorImpl<uint64_t> &Record, unsigned &Abbrev);
301   void writeDISubrange(const DISubrange *N, SmallVectorImpl<uint64_t> &Record,
302                        unsigned Abbrev);
303   void writeDIGenericSubrange(const DIGenericSubrange *N,
304                               SmallVectorImpl<uint64_t> &Record,
305                               unsigned Abbrev);
306   void writeDIEnumerator(const DIEnumerator *N,
307                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
308   void writeDIBasicType(const DIBasicType *N, SmallVectorImpl<uint64_t> &Record,
309                         unsigned Abbrev);
310   void writeDIStringType(const DIStringType *N,
311                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
312   void writeDIDerivedType(const DIDerivedType *N,
313                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
314   void writeDICompositeType(const DICompositeType *N,
315                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
316   void writeDISubroutineType(const DISubroutineType *N,
317                              SmallVectorImpl<uint64_t> &Record,
318                              unsigned Abbrev);
319   void writeDIFile(const DIFile *N, SmallVectorImpl<uint64_t> &Record,
320                    unsigned Abbrev);
321   void writeDICompileUnit(const DICompileUnit *N,
322                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
323   void writeDISubprogram(const DISubprogram *N,
324                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
325   void writeDILexicalBlock(const DILexicalBlock *N,
326                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
327   void writeDILexicalBlockFile(const DILexicalBlockFile *N,
328                                SmallVectorImpl<uint64_t> &Record,
329                                unsigned Abbrev);
330   void writeDICommonBlock(const DICommonBlock *N,
331                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
332   void writeDINamespace(const DINamespace *N, SmallVectorImpl<uint64_t> &Record,
333                         unsigned Abbrev);
334   void writeDIMacro(const DIMacro *N, SmallVectorImpl<uint64_t> &Record,
335                     unsigned Abbrev);
336   void writeDIMacroFile(const DIMacroFile *N, SmallVectorImpl<uint64_t> &Record,
337                         unsigned Abbrev);
338   void writeDIArgList(const DIArgList *N, SmallVectorImpl<uint64_t> &Record,
339                       unsigned Abbrev);
340   void writeDIModule(const DIModule *N, SmallVectorImpl<uint64_t> &Record,
341                      unsigned Abbrev);
342   void writeDITemplateTypeParameter(const DITemplateTypeParameter *N,
343                                     SmallVectorImpl<uint64_t> &Record,
344                                     unsigned Abbrev);
345   void writeDITemplateValueParameter(const DITemplateValueParameter *N,
346                                      SmallVectorImpl<uint64_t> &Record,
347                                      unsigned Abbrev);
348   void writeDIGlobalVariable(const DIGlobalVariable *N,
349                              SmallVectorImpl<uint64_t> &Record,
350                              unsigned Abbrev);
351   void writeDILocalVariable(const DILocalVariable *N,
352                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
353   void writeDILabel(const DILabel *N,
354                     SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
355   void writeDIExpression(const DIExpression *N,
356                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
357   void writeDIGlobalVariableExpression(const DIGlobalVariableExpression *N,
358                                        SmallVectorImpl<uint64_t> &Record,
359                                        unsigned Abbrev);
360   void writeDIObjCProperty(const DIObjCProperty *N,
361                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
362   void writeDIImportedEntity(const DIImportedEntity *N,
363                              SmallVectorImpl<uint64_t> &Record,
364                              unsigned Abbrev);
365   unsigned createNamedMetadataAbbrev();
366   void writeNamedMetadata(SmallVectorImpl<uint64_t> &Record);
367   unsigned createMetadataStringsAbbrev();
368   void writeMetadataStrings(ArrayRef<const Metadata *> Strings,
369                             SmallVectorImpl<uint64_t> &Record);
370   void writeMetadataRecords(ArrayRef<const Metadata *> MDs,
371                             SmallVectorImpl<uint64_t> &Record,
372                             std::vector<unsigned> *MDAbbrevs = nullptr,
373                             std::vector<uint64_t> *IndexPos = nullptr);
374   void writeModuleMetadata();
375   void writeFunctionMetadata(const Function &F);
376   void writeFunctionMetadataAttachment(const Function &F);
377   void pushGlobalMetadataAttachment(SmallVectorImpl<uint64_t> &Record,
378                                     const GlobalObject &GO);
379   void writeModuleMetadataKinds();
380   void writeOperandBundleTags();
381   void writeSyncScopeNames();
382   void writeConstants(unsigned FirstVal, unsigned LastVal, bool isGlobal);
383   void writeModuleConstants();
384   bool pushValueAndType(const Value *V, unsigned InstID,
385                         SmallVectorImpl<unsigned> &Vals);
386   void writeOperandBundles(const CallBase &CB, unsigned InstID);
387   void pushValue(const Value *V, unsigned InstID,
388                  SmallVectorImpl<unsigned> &Vals);
389   void pushValueSigned(const Value *V, unsigned InstID,
390                        SmallVectorImpl<uint64_t> &Vals);
391   void writeInstruction(const Instruction &I, unsigned InstID,
392                         SmallVectorImpl<unsigned> &Vals);
393   void writeFunctionLevelValueSymbolTable(const ValueSymbolTable &VST);
394   void writeGlobalValueSymbolTable(
395       DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
396   void writeUseList(UseListOrder &&Order);
397   void writeUseListBlock(const Function *F);
398   void
399   writeFunction(const Function &F,
400                 DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
401   void writeBlockInfo();
402   void writeModuleHash(size_t BlockStartPos);
403 
404   unsigned getEncodedSyncScopeID(SyncScope::ID SSID) {
405     return unsigned(SSID);
406   }
407 
408   unsigned getEncodedAlign(MaybeAlign Alignment) { return encode(Alignment); }
409 };
410 
411 /// Class to manage the bitcode writing for a combined index.
412 class IndexBitcodeWriter : public BitcodeWriterBase {
413   /// The combined index to write to bitcode.
414   const ModuleSummaryIndex &Index;
415 
416   /// When writing a subset of the index for distributed backends, client
417   /// provides a map of modules to the corresponding GUIDs/summaries to write.
418   const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex;
419 
420   /// Map that holds the correspondence between the GUID used in the combined
421   /// index and a value id generated by this class to use in references.
422   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
423 
424   /// Tracks the last value id recorded in the GUIDToValueMap.
425   unsigned GlobalValueId = 0;
426 
427 public:
428   /// Constructs a IndexBitcodeWriter object for the given combined index,
429   /// writing to the provided \p Buffer. When writing a subset of the index
430   /// for a distributed backend, provide a \p ModuleToSummariesForIndex map.
431   IndexBitcodeWriter(BitstreamWriter &Stream, StringTableBuilder &StrtabBuilder,
432                      const ModuleSummaryIndex &Index,
433                      const std::map<std::string, GVSummaryMapTy>
434                          *ModuleToSummariesForIndex = nullptr)
435       : BitcodeWriterBase(Stream, StrtabBuilder), Index(Index),
436         ModuleToSummariesForIndex(ModuleToSummariesForIndex) {
437     // Assign unique value ids to all summaries to be written, for use
438     // in writing out the call graph edges. Save the mapping from GUID
439     // to the new global value id to use when writing those edges, which
440     // are currently saved in the index in terms of GUID.
441     forEachSummary([&](GVInfo I, bool) {
442       GUIDToValueIdMap[I.first] = ++GlobalValueId;
443     });
444   }
445 
446   /// The below iterator returns the GUID and associated summary.
447   using GVInfo = std::pair<GlobalValue::GUID, GlobalValueSummary *>;
448 
449   /// Calls the callback for each value GUID and summary to be written to
450   /// bitcode. This hides the details of whether they are being pulled from the
451   /// entire index or just those in a provided ModuleToSummariesForIndex map.
452   template<typename Functor>
453   void forEachSummary(Functor Callback) {
454     if (ModuleToSummariesForIndex) {
455       for (auto &M : *ModuleToSummariesForIndex)
456         for (auto &Summary : M.second) {
457           Callback(Summary, false);
458           // Ensure aliasee is handled, e.g. for assigning a valueId,
459           // even if we are not importing the aliasee directly (the
460           // imported alias will contain a copy of aliasee).
461           if (auto *AS = dyn_cast<AliasSummary>(Summary.getSecond()))
462             Callback({AS->getAliaseeGUID(), &AS->getAliasee()}, true);
463         }
464     } else {
465       for (auto &Summaries : Index)
466         for (auto &Summary : Summaries.second.SummaryList)
467           Callback({Summaries.first, Summary.get()}, false);
468     }
469   }
470 
471   /// Calls the callback for each entry in the modulePaths StringMap that
472   /// should be written to the module path string table. This hides the details
473   /// of whether they are being pulled from the entire index or just those in a
474   /// provided ModuleToSummariesForIndex map.
475   template <typename Functor> void forEachModule(Functor Callback) {
476     if (ModuleToSummariesForIndex) {
477       for (const auto &M : *ModuleToSummariesForIndex) {
478         const auto &MPI = Index.modulePaths().find(M.first);
479         if (MPI == Index.modulePaths().end()) {
480           // This should only happen if the bitcode file was empty, in which
481           // case we shouldn't be importing (the ModuleToSummariesForIndex
482           // would only include the module we are writing and index for).
483           assert(ModuleToSummariesForIndex->size() == 1);
484           continue;
485         }
486         Callback(*MPI);
487       }
488     } else {
489       for (const auto &MPSE : Index.modulePaths())
490         Callback(MPSE);
491     }
492   }
493 
494   /// Main entry point for writing a combined index to bitcode.
495   void write();
496 
497 private:
498   void writeModStrings();
499   void writeCombinedGlobalValueSummary();
500 
501   Optional<unsigned> getValueId(GlobalValue::GUID ValGUID) {
502     auto VMI = GUIDToValueIdMap.find(ValGUID);
503     if (VMI == GUIDToValueIdMap.end())
504       return None;
505     return VMI->second;
506   }
507 
508   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
509 };
510 
511 } // end anonymous namespace
512 
513 static unsigned getEncodedCastOpcode(unsigned Opcode) {
514   switch (Opcode) {
515   default: llvm_unreachable("Unknown cast instruction!");
516   case Instruction::Trunc   : return bitc::CAST_TRUNC;
517   case Instruction::ZExt    : return bitc::CAST_ZEXT;
518   case Instruction::SExt    : return bitc::CAST_SEXT;
519   case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
520   case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
521   case Instruction::UIToFP  : return bitc::CAST_UITOFP;
522   case Instruction::SIToFP  : return bitc::CAST_SITOFP;
523   case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
524   case Instruction::FPExt   : return bitc::CAST_FPEXT;
525   case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
526   case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
527   case Instruction::BitCast : return bitc::CAST_BITCAST;
528   case Instruction::AddrSpaceCast: return bitc::CAST_ADDRSPACECAST;
529   }
530 }
531 
532 static unsigned getEncodedUnaryOpcode(unsigned Opcode) {
533   switch (Opcode) {
534   default: llvm_unreachable("Unknown binary instruction!");
535   case Instruction::FNeg: return bitc::UNOP_FNEG;
536   }
537 }
538 
539 static unsigned getEncodedBinaryOpcode(unsigned Opcode) {
540   switch (Opcode) {
541   default: llvm_unreachable("Unknown binary instruction!");
542   case Instruction::Add:
543   case Instruction::FAdd: return bitc::BINOP_ADD;
544   case Instruction::Sub:
545   case Instruction::FSub: return bitc::BINOP_SUB;
546   case Instruction::Mul:
547   case Instruction::FMul: return bitc::BINOP_MUL;
548   case Instruction::UDiv: return bitc::BINOP_UDIV;
549   case Instruction::FDiv:
550   case Instruction::SDiv: return bitc::BINOP_SDIV;
551   case Instruction::URem: return bitc::BINOP_UREM;
552   case Instruction::FRem:
553   case Instruction::SRem: return bitc::BINOP_SREM;
554   case Instruction::Shl:  return bitc::BINOP_SHL;
555   case Instruction::LShr: return bitc::BINOP_LSHR;
556   case Instruction::AShr: return bitc::BINOP_ASHR;
557   case Instruction::And:  return bitc::BINOP_AND;
558   case Instruction::Or:   return bitc::BINOP_OR;
559   case Instruction::Xor:  return bitc::BINOP_XOR;
560   }
561 }
562 
563 static unsigned getEncodedRMWOperation(AtomicRMWInst::BinOp Op) {
564   switch (Op) {
565   default: llvm_unreachable("Unknown RMW operation!");
566   case AtomicRMWInst::Xchg: return bitc::RMW_XCHG;
567   case AtomicRMWInst::Add: return bitc::RMW_ADD;
568   case AtomicRMWInst::Sub: return bitc::RMW_SUB;
569   case AtomicRMWInst::And: return bitc::RMW_AND;
570   case AtomicRMWInst::Nand: return bitc::RMW_NAND;
571   case AtomicRMWInst::Or: return bitc::RMW_OR;
572   case AtomicRMWInst::Xor: return bitc::RMW_XOR;
573   case AtomicRMWInst::Max: return bitc::RMW_MAX;
574   case AtomicRMWInst::Min: return bitc::RMW_MIN;
575   case AtomicRMWInst::UMax: return bitc::RMW_UMAX;
576   case AtomicRMWInst::UMin: return bitc::RMW_UMIN;
577   case AtomicRMWInst::FAdd: return bitc::RMW_FADD;
578   case AtomicRMWInst::FSub: return bitc::RMW_FSUB;
579   }
580 }
581 
582 static unsigned getEncodedOrdering(AtomicOrdering Ordering) {
583   switch (Ordering) {
584   case AtomicOrdering::NotAtomic: return bitc::ORDERING_NOTATOMIC;
585   case AtomicOrdering::Unordered: return bitc::ORDERING_UNORDERED;
586   case AtomicOrdering::Monotonic: return bitc::ORDERING_MONOTONIC;
587   case AtomicOrdering::Acquire: return bitc::ORDERING_ACQUIRE;
588   case AtomicOrdering::Release: return bitc::ORDERING_RELEASE;
589   case AtomicOrdering::AcquireRelease: return bitc::ORDERING_ACQREL;
590   case AtomicOrdering::SequentiallyConsistent: return bitc::ORDERING_SEQCST;
591   }
592   llvm_unreachable("Invalid ordering");
593 }
594 
595 static void writeStringRecord(BitstreamWriter &Stream, unsigned Code,
596                               StringRef Str, unsigned AbbrevToUse) {
597   SmallVector<unsigned, 64> Vals;
598 
599   // Code: [strchar x N]
600   for (char C : Str) {
601     if (AbbrevToUse && !BitCodeAbbrevOp::isChar6(C))
602       AbbrevToUse = 0;
603     Vals.push_back(C);
604   }
605 
606   // Emit the finished record.
607   Stream.EmitRecord(Code, Vals, AbbrevToUse);
608 }
609 
610 static uint64_t getAttrKindEncoding(Attribute::AttrKind Kind) {
611   switch (Kind) {
612   case Attribute::Alignment:
613     return bitc::ATTR_KIND_ALIGNMENT;
614   case Attribute::AllocAlign:
615     return bitc::ATTR_KIND_ALLOC_ALIGN;
616   case Attribute::AllocSize:
617     return bitc::ATTR_KIND_ALLOC_SIZE;
618   case Attribute::AlwaysInline:
619     return bitc::ATTR_KIND_ALWAYS_INLINE;
620   case Attribute::ArgMemOnly:
621     return bitc::ATTR_KIND_ARGMEMONLY;
622   case Attribute::Builtin:
623     return bitc::ATTR_KIND_BUILTIN;
624   case Attribute::ByVal:
625     return bitc::ATTR_KIND_BY_VAL;
626   case Attribute::Convergent:
627     return bitc::ATTR_KIND_CONVERGENT;
628   case Attribute::InAlloca:
629     return bitc::ATTR_KIND_IN_ALLOCA;
630   case Attribute::Cold:
631     return bitc::ATTR_KIND_COLD;
632   case Attribute::DisableSanitizerInstrumentation:
633     return bitc::ATTR_KIND_DISABLE_SANITIZER_INSTRUMENTATION;
634   case Attribute::Hot:
635     return bitc::ATTR_KIND_HOT;
636   case Attribute::ElementType:
637     return bitc::ATTR_KIND_ELEMENTTYPE;
638   case Attribute::InaccessibleMemOnly:
639     return bitc::ATTR_KIND_INACCESSIBLEMEM_ONLY;
640   case Attribute::InaccessibleMemOrArgMemOnly:
641     return bitc::ATTR_KIND_INACCESSIBLEMEM_OR_ARGMEMONLY;
642   case Attribute::InlineHint:
643     return bitc::ATTR_KIND_INLINE_HINT;
644   case Attribute::InReg:
645     return bitc::ATTR_KIND_IN_REG;
646   case Attribute::JumpTable:
647     return bitc::ATTR_KIND_JUMP_TABLE;
648   case Attribute::MinSize:
649     return bitc::ATTR_KIND_MIN_SIZE;
650   case Attribute::Naked:
651     return bitc::ATTR_KIND_NAKED;
652   case Attribute::Nest:
653     return bitc::ATTR_KIND_NEST;
654   case Attribute::NoAlias:
655     return bitc::ATTR_KIND_NO_ALIAS;
656   case Attribute::NoBuiltin:
657     return bitc::ATTR_KIND_NO_BUILTIN;
658   case Attribute::NoCallback:
659     return bitc::ATTR_KIND_NO_CALLBACK;
660   case Attribute::NoCapture:
661     return bitc::ATTR_KIND_NO_CAPTURE;
662   case Attribute::NoDuplicate:
663     return bitc::ATTR_KIND_NO_DUPLICATE;
664   case Attribute::NoFree:
665     return bitc::ATTR_KIND_NOFREE;
666   case Attribute::NoImplicitFloat:
667     return bitc::ATTR_KIND_NO_IMPLICIT_FLOAT;
668   case Attribute::NoInline:
669     return bitc::ATTR_KIND_NO_INLINE;
670   case Attribute::NoRecurse:
671     return bitc::ATTR_KIND_NO_RECURSE;
672   case Attribute::NoMerge:
673     return bitc::ATTR_KIND_NO_MERGE;
674   case Attribute::NonLazyBind:
675     return bitc::ATTR_KIND_NON_LAZY_BIND;
676   case Attribute::NonNull:
677     return bitc::ATTR_KIND_NON_NULL;
678   case Attribute::Dereferenceable:
679     return bitc::ATTR_KIND_DEREFERENCEABLE;
680   case Attribute::DereferenceableOrNull:
681     return bitc::ATTR_KIND_DEREFERENCEABLE_OR_NULL;
682   case Attribute::NoRedZone:
683     return bitc::ATTR_KIND_NO_RED_ZONE;
684   case Attribute::NoReturn:
685     return bitc::ATTR_KIND_NO_RETURN;
686   case Attribute::NoSync:
687     return bitc::ATTR_KIND_NOSYNC;
688   case Attribute::NoCfCheck:
689     return bitc::ATTR_KIND_NOCF_CHECK;
690   case Attribute::NoProfile:
691     return bitc::ATTR_KIND_NO_PROFILE;
692   case Attribute::NoUnwind:
693     return bitc::ATTR_KIND_NO_UNWIND;
694   case Attribute::NoSanitizeBounds:
695     return bitc::ATTR_KIND_NO_SANITIZE_BOUNDS;
696   case Attribute::NoSanitizeCoverage:
697     return bitc::ATTR_KIND_NO_SANITIZE_COVERAGE;
698   case Attribute::NullPointerIsValid:
699     return bitc::ATTR_KIND_NULL_POINTER_IS_VALID;
700   case Attribute::OptForFuzzing:
701     return bitc::ATTR_KIND_OPT_FOR_FUZZING;
702   case Attribute::OptimizeForSize:
703     return bitc::ATTR_KIND_OPTIMIZE_FOR_SIZE;
704   case Attribute::OptimizeNone:
705     return bitc::ATTR_KIND_OPTIMIZE_NONE;
706   case Attribute::ReadNone:
707     return bitc::ATTR_KIND_READ_NONE;
708   case Attribute::ReadOnly:
709     return bitc::ATTR_KIND_READ_ONLY;
710   case Attribute::Returned:
711     return bitc::ATTR_KIND_RETURNED;
712   case Attribute::ReturnsTwice:
713     return bitc::ATTR_KIND_RETURNS_TWICE;
714   case Attribute::SExt:
715     return bitc::ATTR_KIND_S_EXT;
716   case Attribute::Speculatable:
717     return bitc::ATTR_KIND_SPECULATABLE;
718   case Attribute::StackAlignment:
719     return bitc::ATTR_KIND_STACK_ALIGNMENT;
720   case Attribute::StackProtect:
721     return bitc::ATTR_KIND_STACK_PROTECT;
722   case Attribute::StackProtectReq:
723     return bitc::ATTR_KIND_STACK_PROTECT_REQ;
724   case Attribute::StackProtectStrong:
725     return bitc::ATTR_KIND_STACK_PROTECT_STRONG;
726   case Attribute::SafeStack:
727     return bitc::ATTR_KIND_SAFESTACK;
728   case Attribute::ShadowCallStack:
729     return bitc::ATTR_KIND_SHADOWCALLSTACK;
730   case Attribute::StrictFP:
731     return bitc::ATTR_KIND_STRICT_FP;
732   case Attribute::StructRet:
733     return bitc::ATTR_KIND_STRUCT_RET;
734   case Attribute::SanitizeAddress:
735     return bitc::ATTR_KIND_SANITIZE_ADDRESS;
736   case Attribute::SanitizeHWAddress:
737     return bitc::ATTR_KIND_SANITIZE_HWADDRESS;
738   case Attribute::SanitizeThread:
739     return bitc::ATTR_KIND_SANITIZE_THREAD;
740   case Attribute::SanitizeMemory:
741     return bitc::ATTR_KIND_SANITIZE_MEMORY;
742   case Attribute::SpeculativeLoadHardening:
743     return bitc::ATTR_KIND_SPECULATIVE_LOAD_HARDENING;
744   case Attribute::SwiftError:
745     return bitc::ATTR_KIND_SWIFT_ERROR;
746   case Attribute::SwiftSelf:
747     return bitc::ATTR_KIND_SWIFT_SELF;
748   case Attribute::SwiftAsync:
749     return bitc::ATTR_KIND_SWIFT_ASYNC;
750   case Attribute::UWTable:
751     return bitc::ATTR_KIND_UW_TABLE;
752   case Attribute::VScaleRange:
753     return bitc::ATTR_KIND_VSCALE_RANGE;
754   case Attribute::WillReturn:
755     return bitc::ATTR_KIND_WILLRETURN;
756   case Attribute::WriteOnly:
757     return bitc::ATTR_KIND_WRITEONLY;
758   case Attribute::ZExt:
759     return bitc::ATTR_KIND_Z_EXT;
760   case Attribute::ImmArg:
761     return bitc::ATTR_KIND_IMMARG;
762   case Attribute::SanitizeMemTag:
763     return bitc::ATTR_KIND_SANITIZE_MEMTAG;
764   case Attribute::Preallocated:
765     return bitc::ATTR_KIND_PREALLOCATED;
766   case Attribute::NoUndef:
767     return bitc::ATTR_KIND_NOUNDEF;
768   case Attribute::ByRef:
769     return bitc::ATTR_KIND_BYREF;
770   case Attribute::MustProgress:
771     return bitc::ATTR_KIND_MUSTPROGRESS;
772   case Attribute::EndAttrKinds:
773     llvm_unreachable("Can not encode end-attribute kinds marker.");
774   case Attribute::None:
775     llvm_unreachable("Can not encode none-attribute.");
776   case Attribute::EmptyKey:
777   case Attribute::TombstoneKey:
778     llvm_unreachable("Trying to encode EmptyKey/TombstoneKey");
779   }
780 
781   llvm_unreachable("Trying to encode unknown attribute");
782 }
783 
784 void ModuleBitcodeWriter::writeAttributeGroupTable() {
785   const std::vector<ValueEnumerator::IndexAndAttrSet> &AttrGrps =
786       VE.getAttributeGroups();
787   if (AttrGrps.empty()) return;
788 
789   Stream.EnterSubblock(bitc::PARAMATTR_GROUP_BLOCK_ID, 3);
790 
791   SmallVector<uint64_t, 64> Record;
792   for (ValueEnumerator::IndexAndAttrSet Pair : AttrGrps) {
793     unsigned AttrListIndex = Pair.first;
794     AttributeSet AS = Pair.second;
795     Record.push_back(VE.getAttributeGroupID(Pair));
796     Record.push_back(AttrListIndex);
797 
798     for (Attribute Attr : AS) {
799       if (Attr.isEnumAttribute()) {
800         Record.push_back(0);
801         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
802       } else if (Attr.isIntAttribute()) {
803         Record.push_back(1);
804         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
805         Record.push_back(Attr.getValueAsInt());
806       } else if (Attr.isStringAttribute()) {
807         StringRef Kind = Attr.getKindAsString();
808         StringRef Val = Attr.getValueAsString();
809 
810         Record.push_back(Val.empty() ? 3 : 4);
811         Record.append(Kind.begin(), Kind.end());
812         Record.push_back(0);
813         if (!Val.empty()) {
814           Record.append(Val.begin(), Val.end());
815           Record.push_back(0);
816         }
817       } else {
818         assert(Attr.isTypeAttribute());
819         Type *Ty = Attr.getValueAsType();
820         Record.push_back(Ty ? 6 : 5);
821         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
822         if (Ty)
823           Record.push_back(VE.getTypeID(Attr.getValueAsType()));
824       }
825     }
826 
827     Stream.EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
828     Record.clear();
829   }
830 
831   Stream.ExitBlock();
832 }
833 
834 void ModuleBitcodeWriter::writeAttributeTable() {
835   const std::vector<AttributeList> &Attrs = VE.getAttributeLists();
836   if (Attrs.empty()) return;
837 
838   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
839 
840   SmallVector<uint64_t, 64> Record;
841   for (const AttributeList &AL : Attrs) {
842     for (unsigned i : AL.indexes()) {
843       AttributeSet AS = AL.getAttributes(i);
844       if (AS.hasAttributes())
845         Record.push_back(VE.getAttributeGroupID({i, AS}));
846     }
847 
848     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
849     Record.clear();
850   }
851 
852   Stream.ExitBlock();
853 }
854 
855 /// WriteTypeTable - Write out the type table for a module.
856 void ModuleBitcodeWriter::writeTypeTable() {
857   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
858 
859   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
860   SmallVector<uint64_t, 64> TypeVals;
861 
862   uint64_t NumBits = VE.computeBitsRequiredForTypeIndicies();
863 
864   // Abbrev for TYPE_CODE_POINTER.
865   auto Abbv = std::make_shared<BitCodeAbbrev>();
866   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
867   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
868   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
869   unsigned PtrAbbrev = Stream.EmitAbbrev(std::move(Abbv));
870 
871   // Abbrev for TYPE_CODE_OPAQUE_POINTER.
872   Abbv = std::make_shared<BitCodeAbbrev>();
873   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_OPAQUE_POINTER));
874   Abbv->Add(BitCodeAbbrevOp(0)); // Addrspace = 0
875   unsigned OpaquePtrAbbrev = Stream.EmitAbbrev(std::move(Abbv));
876 
877   // Abbrev for TYPE_CODE_FUNCTION.
878   Abbv = std::make_shared<BitCodeAbbrev>();
879   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
880   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
881   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
882   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
883   unsigned FunctionAbbrev = Stream.EmitAbbrev(std::move(Abbv));
884 
885   // Abbrev for TYPE_CODE_STRUCT_ANON.
886   Abbv = std::make_shared<BitCodeAbbrev>();
887   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
888   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
889   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
890   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
891   unsigned StructAnonAbbrev = Stream.EmitAbbrev(std::move(Abbv));
892 
893   // Abbrev for TYPE_CODE_STRUCT_NAME.
894   Abbv = std::make_shared<BitCodeAbbrev>();
895   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
896   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
897   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
898   unsigned StructNameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
899 
900   // Abbrev for TYPE_CODE_STRUCT_NAMED.
901   Abbv = std::make_shared<BitCodeAbbrev>();
902   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
903   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
904   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
905   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
906   unsigned StructNamedAbbrev = Stream.EmitAbbrev(std::move(Abbv));
907 
908   // Abbrev for TYPE_CODE_ARRAY.
909   Abbv = std::make_shared<BitCodeAbbrev>();
910   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
911   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
912   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
913   unsigned ArrayAbbrev = Stream.EmitAbbrev(std::move(Abbv));
914 
915   // Emit an entry count so the reader can reserve space.
916   TypeVals.push_back(TypeList.size());
917   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
918   TypeVals.clear();
919 
920   // Loop over all of the types, emitting each in turn.
921   for (Type *T : TypeList) {
922     int AbbrevToUse = 0;
923     unsigned Code = 0;
924 
925     switch (T->getTypeID()) {
926     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;      break;
927     case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;      break;
928     case Type::BFloatTyID:    Code = bitc::TYPE_CODE_BFLOAT;    break;
929     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;     break;
930     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE;    break;
931     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80;  break;
932     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128;     break;
933     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
934     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;     break;
935     case Type::MetadataTyID:  Code = bitc::TYPE_CODE_METADATA;  break;
936     case Type::X86_MMXTyID:   Code = bitc::TYPE_CODE_X86_MMX;   break;
937     case Type::X86_AMXTyID:   Code = bitc::TYPE_CODE_X86_AMX;   break;
938     case Type::TokenTyID:     Code = bitc::TYPE_CODE_TOKEN;     break;
939     case Type::IntegerTyID:
940       // INTEGER: [width]
941       Code = bitc::TYPE_CODE_INTEGER;
942       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
943       break;
944     case Type::PointerTyID: {
945       PointerType *PTy = cast<PointerType>(T);
946       unsigned AddressSpace = PTy->getAddressSpace();
947       if (PTy->isOpaque()) {
948         // OPAQUE_POINTER: [address space]
949         Code = bitc::TYPE_CODE_OPAQUE_POINTER;
950         TypeVals.push_back(AddressSpace);
951         if (AddressSpace == 0)
952           AbbrevToUse = OpaquePtrAbbrev;
953       } else {
954         // POINTER: [pointee type, address space]
955         Code = bitc::TYPE_CODE_POINTER;
956         TypeVals.push_back(VE.getTypeID(PTy->getNonOpaquePointerElementType()));
957         TypeVals.push_back(AddressSpace);
958         if (AddressSpace == 0)
959           AbbrevToUse = PtrAbbrev;
960       }
961       break;
962     }
963     case Type::FunctionTyID: {
964       FunctionType *FT = cast<FunctionType>(T);
965       // FUNCTION: [isvararg, retty, paramty x N]
966       Code = bitc::TYPE_CODE_FUNCTION;
967       TypeVals.push_back(FT->isVarArg());
968       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
969       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
970         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
971       AbbrevToUse = FunctionAbbrev;
972       break;
973     }
974     case Type::StructTyID: {
975       StructType *ST = cast<StructType>(T);
976       // STRUCT: [ispacked, eltty x N]
977       TypeVals.push_back(ST->isPacked());
978       // Output all of the element types.
979       for (Type *ET : ST->elements())
980         TypeVals.push_back(VE.getTypeID(ET));
981 
982       if (ST->isLiteral()) {
983         Code = bitc::TYPE_CODE_STRUCT_ANON;
984         AbbrevToUse = StructAnonAbbrev;
985       } else {
986         if (ST->isOpaque()) {
987           Code = bitc::TYPE_CODE_OPAQUE;
988         } else {
989           Code = bitc::TYPE_CODE_STRUCT_NAMED;
990           AbbrevToUse = StructNamedAbbrev;
991         }
992 
993         // Emit the name if it is present.
994         if (!ST->getName().empty())
995           writeStringRecord(Stream, bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
996                             StructNameAbbrev);
997       }
998       break;
999     }
1000     case Type::ArrayTyID: {
1001       ArrayType *AT = cast<ArrayType>(T);
1002       // ARRAY: [numelts, eltty]
1003       Code = bitc::TYPE_CODE_ARRAY;
1004       TypeVals.push_back(AT->getNumElements());
1005       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
1006       AbbrevToUse = ArrayAbbrev;
1007       break;
1008     }
1009     case Type::FixedVectorTyID:
1010     case Type::ScalableVectorTyID: {
1011       VectorType *VT = cast<VectorType>(T);
1012       // VECTOR [numelts, eltty] or
1013       //        [numelts, eltty, scalable]
1014       Code = bitc::TYPE_CODE_VECTOR;
1015       TypeVals.push_back(VT->getElementCount().getKnownMinValue());
1016       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
1017       if (isa<ScalableVectorType>(VT))
1018         TypeVals.push_back(true);
1019       break;
1020     }
1021     }
1022 
1023     // Emit the finished record.
1024     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
1025     TypeVals.clear();
1026   }
1027 
1028   Stream.ExitBlock();
1029 }
1030 
1031 static unsigned getEncodedLinkage(const GlobalValue::LinkageTypes Linkage) {
1032   switch (Linkage) {
1033   case GlobalValue::ExternalLinkage:
1034     return 0;
1035   case GlobalValue::WeakAnyLinkage:
1036     return 16;
1037   case GlobalValue::AppendingLinkage:
1038     return 2;
1039   case GlobalValue::InternalLinkage:
1040     return 3;
1041   case GlobalValue::LinkOnceAnyLinkage:
1042     return 18;
1043   case GlobalValue::ExternalWeakLinkage:
1044     return 7;
1045   case GlobalValue::CommonLinkage:
1046     return 8;
1047   case GlobalValue::PrivateLinkage:
1048     return 9;
1049   case GlobalValue::WeakODRLinkage:
1050     return 17;
1051   case GlobalValue::LinkOnceODRLinkage:
1052     return 19;
1053   case GlobalValue::AvailableExternallyLinkage:
1054     return 12;
1055   }
1056   llvm_unreachable("Invalid linkage");
1057 }
1058 
1059 static unsigned getEncodedLinkage(const GlobalValue &GV) {
1060   return getEncodedLinkage(GV.getLinkage());
1061 }
1062 
1063 static uint64_t getEncodedFFlags(FunctionSummary::FFlags Flags) {
1064   uint64_t RawFlags = 0;
1065   RawFlags |= Flags.ReadNone;
1066   RawFlags |= (Flags.ReadOnly << 1);
1067   RawFlags |= (Flags.NoRecurse << 2);
1068   RawFlags |= (Flags.ReturnDoesNotAlias << 3);
1069   RawFlags |= (Flags.NoInline << 4);
1070   RawFlags |= (Flags.AlwaysInline << 5);
1071   RawFlags |= (Flags.NoUnwind << 6);
1072   RawFlags |= (Flags.MayThrow << 7);
1073   RawFlags |= (Flags.HasUnknownCall << 8);
1074   RawFlags |= (Flags.MustBeUnreachable << 9);
1075   return RawFlags;
1076 }
1077 
1078 // Decode the flags for GlobalValue in the summary. See getDecodedGVSummaryFlags
1079 // in BitcodeReader.cpp.
1080 static uint64_t getEncodedGVSummaryFlags(GlobalValueSummary::GVFlags Flags) {
1081   uint64_t RawFlags = 0;
1082 
1083   RawFlags |= Flags.NotEligibleToImport; // bool
1084   RawFlags |= (Flags.Live << 1);
1085   RawFlags |= (Flags.DSOLocal << 2);
1086   RawFlags |= (Flags.CanAutoHide << 3);
1087 
1088   // Linkage don't need to be remapped at that time for the summary. Any future
1089   // change to the getEncodedLinkage() function will need to be taken into
1090   // account here as well.
1091   RawFlags = (RawFlags << 4) | Flags.Linkage; // 4 bits
1092 
1093   RawFlags |= (Flags.Visibility << 8); // 2 bits
1094 
1095   return RawFlags;
1096 }
1097 
1098 static uint64_t getEncodedGVarFlags(GlobalVarSummary::GVarFlags Flags) {
1099   uint64_t RawFlags = Flags.MaybeReadOnly | (Flags.MaybeWriteOnly << 1) |
1100                       (Flags.Constant << 2) | Flags.VCallVisibility << 3;
1101   return RawFlags;
1102 }
1103 
1104 static unsigned getEncodedVisibility(const GlobalValue &GV) {
1105   switch (GV.getVisibility()) {
1106   case GlobalValue::DefaultVisibility:   return 0;
1107   case GlobalValue::HiddenVisibility:    return 1;
1108   case GlobalValue::ProtectedVisibility: return 2;
1109   }
1110   llvm_unreachable("Invalid visibility");
1111 }
1112 
1113 static unsigned getEncodedDLLStorageClass(const GlobalValue &GV) {
1114   switch (GV.getDLLStorageClass()) {
1115   case GlobalValue::DefaultStorageClass:   return 0;
1116   case GlobalValue::DLLImportStorageClass: return 1;
1117   case GlobalValue::DLLExportStorageClass: return 2;
1118   }
1119   llvm_unreachable("Invalid DLL storage class");
1120 }
1121 
1122 static unsigned getEncodedThreadLocalMode(const GlobalValue &GV) {
1123   switch (GV.getThreadLocalMode()) {
1124     case GlobalVariable::NotThreadLocal:         return 0;
1125     case GlobalVariable::GeneralDynamicTLSModel: return 1;
1126     case GlobalVariable::LocalDynamicTLSModel:   return 2;
1127     case GlobalVariable::InitialExecTLSModel:    return 3;
1128     case GlobalVariable::LocalExecTLSModel:      return 4;
1129   }
1130   llvm_unreachable("Invalid TLS model");
1131 }
1132 
1133 static unsigned getEncodedComdatSelectionKind(const Comdat &C) {
1134   switch (C.getSelectionKind()) {
1135   case Comdat::Any:
1136     return bitc::COMDAT_SELECTION_KIND_ANY;
1137   case Comdat::ExactMatch:
1138     return bitc::COMDAT_SELECTION_KIND_EXACT_MATCH;
1139   case Comdat::Largest:
1140     return bitc::COMDAT_SELECTION_KIND_LARGEST;
1141   case Comdat::NoDeduplicate:
1142     return bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES;
1143   case Comdat::SameSize:
1144     return bitc::COMDAT_SELECTION_KIND_SAME_SIZE;
1145   }
1146   llvm_unreachable("Invalid selection kind");
1147 }
1148 
1149 static unsigned getEncodedUnnamedAddr(const GlobalValue &GV) {
1150   switch (GV.getUnnamedAddr()) {
1151   case GlobalValue::UnnamedAddr::None:   return 0;
1152   case GlobalValue::UnnamedAddr::Local:  return 2;
1153   case GlobalValue::UnnamedAddr::Global: return 1;
1154   }
1155   llvm_unreachable("Invalid unnamed_addr");
1156 }
1157 
1158 size_t ModuleBitcodeWriter::addToStrtab(StringRef Str) {
1159   if (GenerateHash)
1160     Hasher.update(Str);
1161   return StrtabBuilder.add(Str);
1162 }
1163 
1164 void ModuleBitcodeWriter::writeComdats() {
1165   SmallVector<unsigned, 64> Vals;
1166   for (const Comdat *C : VE.getComdats()) {
1167     // COMDAT: [strtab offset, strtab size, selection_kind]
1168     Vals.push_back(addToStrtab(C->getName()));
1169     Vals.push_back(C->getName().size());
1170     Vals.push_back(getEncodedComdatSelectionKind(*C));
1171     Stream.EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
1172     Vals.clear();
1173   }
1174 }
1175 
1176 /// Write a record that will eventually hold the word offset of the
1177 /// module-level VST. For now the offset is 0, which will be backpatched
1178 /// after the real VST is written. Saves the bit offset to backpatch.
1179 void ModuleBitcodeWriter::writeValueSymbolTableForwardDecl() {
1180   // Write a placeholder value in for the offset of the real VST,
1181   // which is written after the function blocks so that it can include
1182   // the offset of each function. The placeholder offset will be
1183   // updated when the real VST is written.
1184   auto Abbv = std::make_shared<BitCodeAbbrev>();
1185   Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_VSTOFFSET));
1186   // Blocks are 32-bit aligned, so we can use a 32-bit word offset to
1187   // hold the real VST offset. Must use fixed instead of VBR as we don't
1188   // know how many VBR chunks to reserve ahead of time.
1189   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
1190   unsigned VSTOffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1191 
1192   // Emit the placeholder
1193   uint64_t Vals[] = {bitc::MODULE_CODE_VSTOFFSET, 0};
1194   Stream.EmitRecordWithAbbrev(VSTOffsetAbbrev, Vals);
1195 
1196   // Compute and save the bit offset to the placeholder, which will be
1197   // patched when the real VST is written. We can simply subtract the 32-bit
1198   // fixed size from the current bit number to get the location to backpatch.
1199   VSTOffsetPlaceholder = Stream.GetCurrentBitNo() - 32;
1200 }
1201 
1202 enum StringEncoding { SE_Char6, SE_Fixed7, SE_Fixed8 };
1203 
1204 /// Determine the encoding to use for the given string name and length.
1205 static StringEncoding getStringEncoding(StringRef Str) {
1206   bool isChar6 = true;
1207   for (char C : Str) {
1208     if (isChar6)
1209       isChar6 = BitCodeAbbrevOp::isChar6(C);
1210     if ((unsigned char)C & 128)
1211       // don't bother scanning the rest.
1212       return SE_Fixed8;
1213   }
1214   if (isChar6)
1215     return SE_Char6;
1216   return SE_Fixed7;
1217 }
1218 
1219 /// Emit top-level description of module, including target triple, inline asm,
1220 /// descriptors for global variables, and function prototype info.
1221 /// Returns the bit offset to backpatch with the location of the real VST.
1222 void ModuleBitcodeWriter::writeModuleInfo() {
1223   // Emit various pieces of data attached to a module.
1224   if (!M.getTargetTriple().empty())
1225     writeStringRecord(Stream, bitc::MODULE_CODE_TRIPLE, M.getTargetTriple(),
1226                       0 /*TODO*/);
1227   const std::string &DL = M.getDataLayoutStr();
1228   if (!DL.empty())
1229     writeStringRecord(Stream, bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/);
1230   if (!M.getModuleInlineAsm().empty())
1231     writeStringRecord(Stream, bitc::MODULE_CODE_ASM, M.getModuleInlineAsm(),
1232                       0 /*TODO*/);
1233 
1234   // Emit information about sections and GC, computing how many there are. Also
1235   // compute the maximum alignment value.
1236   std::map<std::string, unsigned> SectionMap;
1237   std::map<std::string, unsigned> GCMap;
1238   MaybeAlign MaxAlignment;
1239   unsigned MaxGlobalType = 0;
1240   const auto UpdateMaxAlignment = [&MaxAlignment](const MaybeAlign A) {
1241     if (A)
1242       MaxAlignment = !MaxAlignment ? *A : std::max(*MaxAlignment, *A);
1243   };
1244   for (const GlobalVariable &GV : M.globals()) {
1245     UpdateMaxAlignment(GV.getAlign());
1246     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getValueType()));
1247     if (GV.hasSection()) {
1248       // Give section names unique ID's.
1249       unsigned &Entry = SectionMap[std::string(GV.getSection())];
1250       if (!Entry) {
1251         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
1252                           0 /*TODO*/);
1253         Entry = SectionMap.size();
1254       }
1255     }
1256   }
1257   for (const Function &F : M) {
1258     UpdateMaxAlignment(F.getAlign());
1259     if (F.hasSection()) {
1260       // Give section names unique ID's.
1261       unsigned &Entry = SectionMap[std::string(F.getSection())];
1262       if (!Entry) {
1263         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
1264                           0 /*TODO*/);
1265         Entry = SectionMap.size();
1266       }
1267     }
1268     if (F.hasGC()) {
1269       // Same for GC names.
1270       unsigned &Entry = GCMap[F.getGC()];
1271       if (!Entry) {
1272         writeStringRecord(Stream, bitc::MODULE_CODE_GCNAME, F.getGC(),
1273                           0 /*TODO*/);
1274         Entry = GCMap.size();
1275       }
1276     }
1277   }
1278 
1279   // Emit abbrev for globals, now that we know # sections and max alignment.
1280   unsigned SimpleGVarAbbrev = 0;
1281   if (!M.global_empty()) {
1282     // Add an abbrev for common globals with no visibility or thread localness.
1283     auto Abbv = std::make_shared<BitCodeAbbrev>();
1284     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
1285     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1286     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1287     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1288                               Log2_32_Ceil(MaxGlobalType+1)));
1289     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddrSpace << 2
1290                                                            //| explicitType << 1
1291                                                            //| constant
1292     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Initializer.
1293     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // Linkage.
1294     if (!MaxAlignment)                                     // Alignment.
1295       Abbv->Add(BitCodeAbbrevOp(0));
1296     else {
1297       unsigned MaxEncAlignment = getEncodedAlign(MaxAlignment);
1298       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1299                                Log2_32_Ceil(MaxEncAlignment+1)));
1300     }
1301     if (SectionMap.empty())                                    // Section.
1302       Abbv->Add(BitCodeAbbrevOp(0));
1303     else
1304       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1305                                Log2_32_Ceil(SectionMap.size()+1)));
1306     // Don't bother emitting vis + thread local.
1307     SimpleGVarAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1308   }
1309 
1310   SmallVector<unsigned, 64> Vals;
1311   // Emit the module's source file name.
1312   {
1313     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
1314     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
1315     if (Bits == SE_Char6)
1316       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
1317     else if (Bits == SE_Fixed7)
1318       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
1319 
1320     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
1321     auto Abbv = std::make_shared<BitCodeAbbrev>();
1322     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
1323     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1324     Abbv->Add(AbbrevOpToUse);
1325     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1326 
1327     for (const auto P : M.getSourceFileName())
1328       Vals.push_back((unsigned char)P);
1329 
1330     // Emit the finished record.
1331     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
1332     Vals.clear();
1333   }
1334 
1335   // Emit the global variable information.
1336   for (const GlobalVariable &GV : M.globals()) {
1337     unsigned AbbrevToUse = 0;
1338 
1339     // GLOBALVAR: [strtab offset, strtab size, type, isconst, initid,
1340     //             linkage, alignment, section, visibility, threadlocal,
1341     //             unnamed_addr, externally_initialized, dllstorageclass,
1342     //             comdat, attributes, DSO_Local]
1343     Vals.push_back(addToStrtab(GV.getName()));
1344     Vals.push_back(GV.getName().size());
1345     Vals.push_back(VE.getTypeID(GV.getValueType()));
1346     Vals.push_back(GV.getType()->getAddressSpace() << 2 | 2 | GV.isConstant());
1347     Vals.push_back(GV.isDeclaration() ? 0 :
1348                    (VE.getValueID(GV.getInitializer()) + 1));
1349     Vals.push_back(getEncodedLinkage(GV));
1350     Vals.push_back(getEncodedAlign(GV.getAlign()));
1351     Vals.push_back(GV.hasSection() ? SectionMap[std::string(GV.getSection())]
1352                                    : 0);
1353     if (GV.isThreadLocal() ||
1354         GV.getVisibility() != GlobalValue::DefaultVisibility ||
1355         GV.getUnnamedAddr() != GlobalValue::UnnamedAddr::None ||
1356         GV.isExternallyInitialized() ||
1357         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
1358         GV.hasComdat() ||
1359         GV.hasAttributes() ||
1360         GV.isDSOLocal() ||
1361         GV.hasPartition()) {
1362       Vals.push_back(getEncodedVisibility(GV));
1363       Vals.push_back(getEncodedThreadLocalMode(GV));
1364       Vals.push_back(getEncodedUnnamedAddr(GV));
1365       Vals.push_back(GV.isExternallyInitialized());
1366       Vals.push_back(getEncodedDLLStorageClass(GV));
1367       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
1368 
1369       auto AL = GV.getAttributesAsList(AttributeList::FunctionIndex);
1370       Vals.push_back(VE.getAttributeListID(AL));
1371 
1372       Vals.push_back(GV.isDSOLocal());
1373       Vals.push_back(addToStrtab(GV.getPartition()));
1374       Vals.push_back(GV.getPartition().size());
1375     } else {
1376       AbbrevToUse = SimpleGVarAbbrev;
1377     }
1378 
1379     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
1380     Vals.clear();
1381   }
1382 
1383   // Emit the function proto information.
1384   for (const Function &F : M) {
1385     // FUNCTION:  [strtab offset, strtab size, type, callingconv, isproto,
1386     //             linkage, paramattrs, alignment, section, visibility, gc,
1387     //             unnamed_addr, prologuedata, dllstorageclass, comdat,
1388     //             prefixdata, personalityfn, DSO_Local, addrspace]
1389     Vals.push_back(addToStrtab(F.getName()));
1390     Vals.push_back(F.getName().size());
1391     Vals.push_back(VE.getTypeID(F.getFunctionType()));
1392     Vals.push_back(F.getCallingConv());
1393     Vals.push_back(F.isDeclaration());
1394     Vals.push_back(getEncodedLinkage(F));
1395     Vals.push_back(VE.getAttributeListID(F.getAttributes()));
1396     Vals.push_back(getEncodedAlign(F.getAlign()));
1397     Vals.push_back(F.hasSection() ? SectionMap[std::string(F.getSection())]
1398                                   : 0);
1399     Vals.push_back(getEncodedVisibility(F));
1400     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
1401     Vals.push_back(getEncodedUnnamedAddr(F));
1402     Vals.push_back(F.hasPrologueData() ? (VE.getValueID(F.getPrologueData()) + 1)
1403                                        : 0);
1404     Vals.push_back(getEncodedDLLStorageClass(F));
1405     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
1406     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
1407                                      : 0);
1408     Vals.push_back(
1409         F.hasPersonalityFn() ? (VE.getValueID(F.getPersonalityFn()) + 1) : 0);
1410 
1411     Vals.push_back(F.isDSOLocal());
1412     Vals.push_back(F.getAddressSpace());
1413     Vals.push_back(addToStrtab(F.getPartition()));
1414     Vals.push_back(F.getPartition().size());
1415 
1416     unsigned AbbrevToUse = 0;
1417     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
1418     Vals.clear();
1419   }
1420 
1421   // Emit the alias information.
1422   for (const GlobalAlias &A : M.aliases()) {
1423     // ALIAS: [strtab offset, strtab size, alias type, aliasee val#, linkage,
1424     //         visibility, dllstorageclass, threadlocal, unnamed_addr,
1425     //         DSO_Local]
1426     Vals.push_back(addToStrtab(A.getName()));
1427     Vals.push_back(A.getName().size());
1428     Vals.push_back(VE.getTypeID(A.getValueType()));
1429     Vals.push_back(A.getType()->getAddressSpace());
1430     Vals.push_back(VE.getValueID(A.getAliasee()));
1431     Vals.push_back(getEncodedLinkage(A));
1432     Vals.push_back(getEncodedVisibility(A));
1433     Vals.push_back(getEncodedDLLStorageClass(A));
1434     Vals.push_back(getEncodedThreadLocalMode(A));
1435     Vals.push_back(getEncodedUnnamedAddr(A));
1436     Vals.push_back(A.isDSOLocal());
1437     Vals.push_back(addToStrtab(A.getPartition()));
1438     Vals.push_back(A.getPartition().size());
1439 
1440     unsigned AbbrevToUse = 0;
1441     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
1442     Vals.clear();
1443   }
1444 
1445   // Emit the ifunc information.
1446   for (const GlobalIFunc &I : M.ifuncs()) {
1447     // IFUNC: [strtab offset, strtab size, ifunc type, address space, resolver
1448     //         val#, linkage, visibility, DSO_Local]
1449     Vals.push_back(addToStrtab(I.getName()));
1450     Vals.push_back(I.getName().size());
1451     Vals.push_back(VE.getTypeID(I.getValueType()));
1452     Vals.push_back(I.getType()->getAddressSpace());
1453     Vals.push_back(VE.getValueID(I.getResolver()));
1454     Vals.push_back(getEncodedLinkage(I));
1455     Vals.push_back(getEncodedVisibility(I));
1456     Vals.push_back(I.isDSOLocal());
1457     Vals.push_back(addToStrtab(I.getPartition()));
1458     Vals.push_back(I.getPartition().size());
1459     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
1460     Vals.clear();
1461   }
1462 
1463   writeValueSymbolTableForwardDecl();
1464 }
1465 
1466 static uint64_t getOptimizationFlags(const Value *V) {
1467   uint64_t Flags = 0;
1468 
1469   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
1470     if (OBO->hasNoSignedWrap())
1471       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
1472     if (OBO->hasNoUnsignedWrap())
1473       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
1474   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
1475     if (PEO->isExact())
1476       Flags |= 1 << bitc::PEO_EXACT;
1477   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
1478     if (FPMO->hasAllowReassoc())
1479       Flags |= bitc::AllowReassoc;
1480     if (FPMO->hasNoNaNs())
1481       Flags |= bitc::NoNaNs;
1482     if (FPMO->hasNoInfs())
1483       Flags |= bitc::NoInfs;
1484     if (FPMO->hasNoSignedZeros())
1485       Flags |= bitc::NoSignedZeros;
1486     if (FPMO->hasAllowReciprocal())
1487       Flags |= bitc::AllowReciprocal;
1488     if (FPMO->hasAllowContract())
1489       Flags |= bitc::AllowContract;
1490     if (FPMO->hasApproxFunc())
1491       Flags |= bitc::ApproxFunc;
1492   }
1493 
1494   return Flags;
1495 }
1496 
1497 void ModuleBitcodeWriter::writeValueAsMetadata(
1498     const ValueAsMetadata *MD, SmallVectorImpl<uint64_t> &Record) {
1499   // Mimic an MDNode with a value as one operand.
1500   Value *V = MD->getValue();
1501   Record.push_back(VE.getTypeID(V->getType()));
1502   Record.push_back(VE.getValueID(V));
1503   Stream.EmitRecord(bitc::METADATA_VALUE, Record, 0);
1504   Record.clear();
1505 }
1506 
1507 void ModuleBitcodeWriter::writeMDTuple(const MDTuple *N,
1508                                        SmallVectorImpl<uint64_t> &Record,
1509                                        unsigned Abbrev) {
1510   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
1511     Metadata *MD = N->getOperand(i);
1512     assert(!(MD && isa<LocalAsMetadata>(MD)) &&
1513            "Unexpected function-local metadata");
1514     Record.push_back(VE.getMetadataOrNullID(MD));
1515   }
1516   Stream.EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
1517                                     : bitc::METADATA_NODE,
1518                     Record, Abbrev);
1519   Record.clear();
1520 }
1521 
1522 unsigned ModuleBitcodeWriter::createDILocationAbbrev() {
1523   // Assume the column is usually under 128, and always output the inlined-at
1524   // location (it's never more expensive than building an array size 1).
1525   auto Abbv = std::make_shared<BitCodeAbbrev>();
1526   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
1527   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1528   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1529   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1530   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1531   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1532   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1533   return Stream.EmitAbbrev(std::move(Abbv));
1534 }
1535 
1536 void ModuleBitcodeWriter::writeDILocation(const DILocation *N,
1537                                           SmallVectorImpl<uint64_t> &Record,
1538                                           unsigned &Abbrev) {
1539   if (!Abbrev)
1540     Abbrev = createDILocationAbbrev();
1541 
1542   Record.push_back(N->isDistinct());
1543   Record.push_back(N->getLine());
1544   Record.push_back(N->getColumn());
1545   Record.push_back(VE.getMetadataID(N->getScope()));
1546   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
1547   Record.push_back(N->isImplicitCode());
1548 
1549   Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
1550   Record.clear();
1551 }
1552 
1553 unsigned ModuleBitcodeWriter::createGenericDINodeAbbrev() {
1554   // Assume the column is usually under 128, and always output the inlined-at
1555   // location (it's never more expensive than building an array size 1).
1556   auto Abbv = std::make_shared<BitCodeAbbrev>();
1557   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
1558   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1559   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1560   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1561   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1562   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1563   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1564   return Stream.EmitAbbrev(std::move(Abbv));
1565 }
1566 
1567 void ModuleBitcodeWriter::writeGenericDINode(const GenericDINode *N,
1568                                              SmallVectorImpl<uint64_t> &Record,
1569                                              unsigned &Abbrev) {
1570   if (!Abbrev)
1571     Abbrev = createGenericDINodeAbbrev();
1572 
1573   Record.push_back(N->isDistinct());
1574   Record.push_back(N->getTag());
1575   Record.push_back(0); // Per-tag version field; unused for now.
1576 
1577   for (auto &I : N->operands())
1578     Record.push_back(VE.getMetadataOrNullID(I));
1579 
1580   Stream.EmitRecord(bitc::METADATA_GENERIC_DEBUG, Record, Abbrev);
1581   Record.clear();
1582 }
1583 
1584 void ModuleBitcodeWriter::writeDISubrange(const DISubrange *N,
1585                                           SmallVectorImpl<uint64_t> &Record,
1586                                           unsigned Abbrev) {
1587   const uint64_t Version = 2 << 1;
1588   Record.push_back((uint64_t)N->isDistinct() | Version);
1589   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1590   Record.push_back(VE.getMetadataOrNullID(N->getRawLowerBound()));
1591   Record.push_back(VE.getMetadataOrNullID(N->getRawUpperBound()));
1592   Record.push_back(VE.getMetadataOrNullID(N->getRawStride()));
1593 
1594   Stream.EmitRecord(bitc::METADATA_SUBRANGE, Record, Abbrev);
1595   Record.clear();
1596 }
1597 
1598 void ModuleBitcodeWriter::writeDIGenericSubrange(
1599     const DIGenericSubrange *N, SmallVectorImpl<uint64_t> &Record,
1600     unsigned Abbrev) {
1601   Record.push_back((uint64_t)N->isDistinct());
1602   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1603   Record.push_back(VE.getMetadataOrNullID(N->getRawLowerBound()));
1604   Record.push_back(VE.getMetadataOrNullID(N->getRawUpperBound()));
1605   Record.push_back(VE.getMetadataOrNullID(N->getRawStride()));
1606 
1607   Stream.EmitRecord(bitc::METADATA_GENERIC_SUBRANGE, Record, Abbrev);
1608   Record.clear();
1609 }
1610 
1611 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
1612   if ((int64_t)V >= 0)
1613     Vals.push_back(V << 1);
1614   else
1615     Vals.push_back((-V << 1) | 1);
1616 }
1617 
1618 static void emitWideAPInt(SmallVectorImpl<uint64_t> &Vals, const APInt &A) {
1619   // We have an arbitrary precision integer value to write whose
1620   // bit width is > 64. However, in canonical unsigned integer
1621   // format it is likely that the high bits are going to be zero.
1622   // So, we only write the number of active words.
1623   unsigned NumWords = A.getActiveWords();
1624   const uint64_t *RawData = A.getRawData();
1625   for (unsigned i = 0; i < NumWords; i++)
1626     emitSignedInt64(Vals, RawData[i]);
1627 }
1628 
1629 void ModuleBitcodeWriter::writeDIEnumerator(const DIEnumerator *N,
1630                                             SmallVectorImpl<uint64_t> &Record,
1631                                             unsigned Abbrev) {
1632   const uint64_t IsBigInt = 1 << 2;
1633   Record.push_back(IsBigInt | (N->isUnsigned() << 1) | N->isDistinct());
1634   Record.push_back(N->getValue().getBitWidth());
1635   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1636   emitWideAPInt(Record, N->getValue());
1637 
1638   Stream.EmitRecord(bitc::METADATA_ENUMERATOR, Record, Abbrev);
1639   Record.clear();
1640 }
1641 
1642 void ModuleBitcodeWriter::writeDIBasicType(const DIBasicType *N,
1643                                            SmallVectorImpl<uint64_t> &Record,
1644                                            unsigned Abbrev) {
1645   Record.push_back(N->isDistinct());
1646   Record.push_back(N->getTag());
1647   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1648   Record.push_back(N->getSizeInBits());
1649   Record.push_back(N->getAlignInBits());
1650   Record.push_back(N->getEncoding());
1651   Record.push_back(N->getFlags());
1652 
1653   Stream.EmitRecord(bitc::METADATA_BASIC_TYPE, Record, Abbrev);
1654   Record.clear();
1655 }
1656 
1657 void ModuleBitcodeWriter::writeDIStringType(const DIStringType *N,
1658                                             SmallVectorImpl<uint64_t> &Record,
1659                                             unsigned Abbrev) {
1660   Record.push_back(N->isDistinct());
1661   Record.push_back(N->getTag());
1662   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1663   Record.push_back(VE.getMetadataOrNullID(N->getStringLength()));
1664   Record.push_back(VE.getMetadataOrNullID(N->getStringLengthExp()));
1665   Record.push_back(VE.getMetadataOrNullID(N->getStringLocationExp()));
1666   Record.push_back(N->getSizeInBits());
1667   Record.push_back(N->getAlignInBits());
1668   Record.push_back(N->getEncoding());
1669 
1670   Stream.EmitRecord(bitc::METADATA_STRING_TYPE, Record, Abbrev);
1671   Record.clear();
1672 }
1673 
1674 void ModuleBitcodeWriter::writeDIDerivedType(const DIDerivedType *N,
1675                                              SmallVectorImpl<uint64_t> &Record,
1676                                              unsigned Abbrev) {
1677   Record.push_back(N->isDistinct());
1678   Record.push_back(N->getTag());
1679   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1680   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1681   Record.push_back(N->getLine());
1682   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1683   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1684   Record.push_back(N->getSizeInBits());
1685   Record.push_back(N->getAlignInBits());
1686   Record.push_back(N->getOffsetInBits());
1687   Record.push_back(N->getFlags());
1688   Record.push_back(VE.getMetadataOrNullID(N->getExtraData()));
1689 
1690   // DWARF address space is encoded as N->getDWARFAddressSpace() + 1. 0 means
1691   // that there is no DWARF address space associated with DIDerivedType.
1692   if (const auto &DWARFAddressSpace = N->getDWARFAddressSpace())
1693     Record.push_back(*DWARFAddressSpace + 1);
1694   else
1695     Record.push_back(0);
1696 
1697   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1698 
1699   Stream.EmitRecord(bitc::METADATA_DERIVED_TYPE, Record, Abbrev);
1700   Record.clear();
1701 }
1702 
1703 void ModuleBitcodeWriter::writeDICompositeType(
1704     const DICompositeType *N, SmallVectorImpl<uint64_t> &Record,
1705     unsigned Abbrev) {
1706   const unsigned IsNotUsedInOldTypeRef = 0x2;
1707   Record.push_back(IsNotUsedInOldTypeRef | (unsigned)N->isDistinct());
1708   Record.push_back(N->getTag());
1709   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1710   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1711   Record.push_back(N->getLine());
1712   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1713   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1714   Record.push_back(N->getSizeInBits());
1715   Record.push_back(N->getAlignInBits());
1716   Record.push_back(N->getOffsetInBits());
1717   Record.push_back(N->getFlags());
1718   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1719   Record.push_back(N->getRuntimeLang());
1720   Record.push_back(VE.getMetadataOrNullID(N->getVTableHolder()));
1721   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1722   Record.push_back(VE.getMetadataOrNullID(N->getRawIdentifier()));
1723   Record.push_back(VE.getMetadataOrNullID(N->getDiscriminator()));
1724   Record.push_back(VE.getMetadataOrNullID(N->getRawDataLocation()));
1725   Record.push_back(VE.getMetadataOrNullID(N->getRawAssociated()));
1726   Record.push_back(VE.getMetadataOrNullID(N->getRawAllocated()));
1727   Record.push_back(VE.getMetadataOrNullID(N->getRawRank()));
1728   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1729 
1730   Stream.EmitRecord(bitc::METADATA_COMPOSITE_TYPE, Record, Abbrev);
1731   Record.clear();
1732 }
1733 
1734 void ModuleBitcodeWriter::writeDISubroutineType(
1735     const DISubroutineType *N, SmallVectorImpl<uint64_t> &Record,
1736     unsigned Abbrev) {
1737   const unsigned HasNoOldTypeRefs = 0x2;
1738   Record.push_back(HasNoOldTypeRefs | (unsigned)N->isDistinct());
1739   Record.push_back(N->getFlags());
1740   Record.push_back(VE.getMetadataOrNullID(N->getTypeArray().get()));
1741   Record.push_back(N->getCC());
1742 
1743   Stream.EmitRecord(bitc::METADATA_SUBROUTINE_TYPE, Record, Abbrev);
1744   Record.clear();
1745 }
1746 
1747 void ModuleBitcodeWriter::writeDIFile(const DIFile *N,
1748                                       SmallVectorImpl<uint64_t> &Record,
1749                                       unsigned Abbrev) {
1750   Record.push_back(N->isDistinct());
1751   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
1752   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
1753   if (N->getRawChecksum()) {
1754     Record.push_back(N->getRawChecksum()->Kind);
1755     Record.push_back(VE.getMetadataOrNullID(N->getRawChecksum()->Value));
1756   } else {
1757     // Maintain backwards compatibility with the old internal representation of
1758     // CSK_None in ChecksumKind by writing nulls here when Checksum is None.
1759     Record.push_back(0);
1760     Record.push_back(VE.getMetadataOrNullID(nullptr));
1761   }
1762   auto Source = N->getRawSource();
1763   if (Source)
1764     Record.push_back(VE.getMetadataOrNullID(*Source));
1765 
1766   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
1767   Record.clear();
1768 }
1769 
1770 void ModuleBitcodeWriter::writeDICompileUnit(const DICompileUnit *N,
1771                                              SmallVectorImpl<uint64_t> &Record,
1772                                              unsigned Abbrev) {
1773   assert(N->isDistinct() && "Expected distinct compile units");
1774   Record.push_back(/* IsDistinct */ true);
1775   Record.push_back(N->getSourceLanguage());
1776   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1777   Record.push_back(VE.getMetadataOrNullID(N->getRawProducer()));
1778   Record.push_back(N->isOptimized());
1779   Record.push_back(VE.getMetadataOrNullID(N->getRawFlags()));
1780   Record.push_back(N->getRuntimeVersion());
1781   Record.push_back(VE.getMetadataOrNullID(N->getRawSplitDebugFilename()));
1782   Record.push_back(N->getEmissionKind());
1783   Record.push_back(VE.getMetadataOrNullID(N->getEnumTypes().get()));
1784   Record.push_back(VE.getMetadataOrNullID(N->getRetainedTypes().get()));
1785   Record.push_back(/* subprograms */ 0);
1786   Record.push_back(VE.getMetadataOrNullID(N->getGlobalVariables().get()));
1787   Record.push_back(VE.getMetadataOrNullID(N->getImportedEntities().get()));
1788   Record.push_back(N->getDWOId());
1789   Record.push_back(VE.getMetadataOrNullID(N->getMacros().get()));
1790   Record.push_back(N->getSplitDebugInlining());
1791   Record.push_back(N->getDebugInfoForProfiling());
1792   Record.push_back((unsigned)N->getNameTableKind());
1793   Record.push_back(N->getRangesBaseAddress());
1794   Record.push_back(VE.getMetadataOrNullID(N->getRawSysRoot()));
1795   Record.push_back(VE.getMetadataOrNullID(N->getRawSDK()));
1796 
1797   Stream.EmitRecord(bitc::METADATA_COMPILE_UNIT, Record, Abbrev);
1798   Record.clear();
1799 }
1800 
1801 void ModuleBitcodeWriter::writeDISubprogram(const DISubprogram *N,
1802                                             SmallVectorImpl<uint64_t> &Record,
1803                                             unsigned Abbrev) {
1804   const uint64_t HasUnitFlag = 1 << 1;
1805   const uint64_t HasSPFlagsFlag = 1 << 2;
1806   Record.push_back(uint64_t(N->isDistinct()) | HasUnitFlag | HasSPFlagsFlag);
1807   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1808   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1809   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1810   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1811   Record.push_back(N->getLine());
1812   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1813   Record.push_back(N->getScopeLine());
1814   Record.push_back(VE.getMetadataOrNullID(N->getContainingType()));
1815   Record.push_back(N->getSPFlags());
1816   Record.push_back(N->getVirtualIndex());
1817   Record.push_back(N->getFlags());
1818   Record.push_back(VE.getMetadataOrNullID(N->getRawUnit()));
1819   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1820   Record.push_back(VE.getMetadataOrNullID(N->getDeclaration()));
1821   Record.push_back(VE.getMetadataOrNullID(N->getRetainedNodes().get()));
1822   Record.push_back(N->getThisAdjustment());
1823   Record.push_back(VE.getMetadataOrNullID(N->getThrownTypes().get()));
1824   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1825 
1826   Stream.EmitRecord(bitc::METADATA_SUBPROGRAM, Record, Abbrev);
1827   Record.clear();
1828 }
1829 
1830 void ModuleBitcodeWriter::writeDILexicalBlock(const DILexicalBlock *N,
1831                                               SmallVectorImpl<uint64_t> &Record,
1832                                               unsigned Abbrev) {
1833   Record.push_back(N->isDistinct());
1834   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1835   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1836   Record.push_back(N->getLine());
1837   Record.push_back(N->getColumn());
1838 
1839   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK, Record, Abbrev);
1840   Record.clear();
1841 }
1842 
1843 void ModuleBitcodeWriter::writeDILexicalBlockFile(
1844     const DILexicalBlockFile *N, SmallVectorImpl<uint64_t> &Record,
1845     unsigned Abbrev) {
1846   Record.push_back(N->isDistinct());
1847   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1848   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1849   Record.push_back(N->getDiscriminator());
1850 
1851   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK_FILE, Record, Abbrev);
1852   Record.clear();
1853 }
1854 
1855 void ModuleBitcodeWriter::writeDICommonBlock(const DICommonBlock *N,
1856                                              SmallVectorImpl<uint64_t> &Record,
1857                                              unsigned Abbrev) {
1858   Record.push_back(N->isDistinct());
1859   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1860   Record.push_back(VE.getMetadataOrNullID(N->getDecl()));
1861   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1862   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1863   Record.push_back(N->getLineNo());
1864 
1865   Stream.EmitRecord(bitc::METADATA_COMMON_BLOCK, Record, Abbrev);
1866   Record.clear();
1867 }
1868 
1869 void ModuleBitcodeWriter::writeDINamespace(const DINamespace *N,
1870                                            SmallVectorImpl<uint64_t> &Record,
1871                                            unsigned Abbrev) {
1872   Record.push_back(N->isDistinct() | N->getExportSymbols() << 1);
1873   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1874   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1875 
1876   Stream.EmitRecord(bitc::METADATA_NAMESPACE, Record, Abbrev);
1877   Record.clear();
1878 }
1879 
1880 void ModuleBitcodeWriter::writeDIMacro(const DIMacro *N,
1881                                        SmallVectorImpl<uint64_t> &Record,
1882                                        unsigned Abbrev) {
1883   Record.push_back(N->isDistinct());
1884   Record.push_back(N->getMacinfoType());
1885   Record.push_back(N->getLine());
1886   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1887   Record.push_back(VE.getMetadataOrNullID(N->getRawValue()));
1888 
1889   Stream.EmitRecord(bitc::METADATA_MACRO, Record, Abbrev);
1890   Record.clear();
1891 }
1892 
1893 void ModuleBitcodeWriter::writeDIMacroFile(const DIMacroFile *N,
1894                                            SmallVectorImpl<uint64_t> &Record,
1895                                            unsigned Abbrev) {
1896   Record.push_back(N->isDistinct());
1897   Record.push_back(N->getMacinfoType());
1898   Record.push_back(N->getLine());
1899   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1900   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1901 
1902   Stream.EmitRecord(bitc::METADATA_MACRO_FILE, Record, Abbrev);
1903   Record.clear();
1904 }
1905 
1906 void ModuleBitcodeWriter::writeDIArgList(const DIArgList *N,
1907                                          SmallVectorImpl<uint64_t> &Record,
1908                                          unsigned Abbrev) {
1909   Record.reserve(N->getArgs().size());
1910   for (ValueAsMetadata *MD : N->getArgs())
1911     Record.push_back(VE.getMetadataID(MD));
1912 
1913   Stream.EmitRecord(bitc::METADATA_ARG_LIST, Record, Abbrev);
1914   Record.clear();
1915 }
1916 
1917 void ModuleBitcodeWriter::writeDIModule(const DIModule *N,
1918                                         SmallVectorImpl<uint64_t> &Record,
1919                                         unsigned Abbrev) {
1920   Record.push_back(N->isDistinct());
1921   for (auto &I : N->operands())
1922     Record.push_back(VE.getMetadataOrNullID(I));
1923   Record.push_back(N->getLineNo());
1924   Record.push_back(N->getIsDecl());
1925 
1926   Stream.EmitRecord(bitc::METADATA_MODULE, Record, Abbrev);
1927   Record.clear();
1928 }
1929 
1930 void ModuleBitcodeWriter::writeDITemplateTypeParameter(
1931     const DITemplateTypeParameter *N, SmallVectorImpl<uint64_t> &Record,
1932     unsigned Abbrev) {
1933   Record.push_back(N->isDistinct());
1934   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1935   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1936   Record.push_back(N->isDefault());
1937 
1938   Stream.EmitRecord(bitc::METADATA_TEMPLATE_TYPE, Record, Abbrev);
1939   Record.clear();
1940 }
1941 
1942 void ModuleBitcodeWriter::writeDITemplateValueParameter(
1943     const DITemplateValueParameter *N, SmallVectorImpl<uint64_t> &Record,
1944     unsigned Abbrev) {
1945   Record.push_back(N->isDistinct());
1946   Record.push_back(N->getTag());
1947   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1948   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1949   Record.push_back(N->isDefault());
1950   Record.push_back(VE.getMetadataOrNullID(N->getValue()));
1951 
1952   Stream.EmitRecord(bitc::METADATA_TEMPLATE_VALUE, Record, Abbrev);
1953   Record.clear();
1954 }
1955 
1956 void ModuleBitcodeWriter::writeDIGlobalVariable(
1957     const DIGlobalVariable *N, SmallVectorImpl<uint64_t> &Record,
1958     unsigned Abbrev) {
1959   const uint64_t Version = 2 << 1;
1960   Record.push_back((uint64_t)N->isDistinct() | Version);
1961   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1962   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1963   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1964   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1965   Record.push_back(N->getLine());
1966   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1967   Record.push_back(N->isLocalToUnit());
1968   Record.push_back(N->isDefinition());
1969   Record.push_back(VE.getMetadataOrNullID(N->getStaticDataMemberDeclaration()));
1970   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams()));
1971   Record.push_back(N->getAlignInBits());
1972   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1973 
1974   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR, Record, Abbrev);
1975   Record.clear();
1976 }
1977 
1978 void ModuleBitcodeWriter::writeDILocalVariable(
1979     const DILocalVariable *N, SmallVectorImpl<uint64_t> &Record,
1980     unsigned Abbrev) {
1981   // In order to support all possible bitcode formats in BitcodeReader we need
1982   // to distinguish the following cases:
1983   // 1) Record has no artificial tag (Record[1]),
1984   //   has no obsolete inlinedAt field (Record[9]).
1985   //   In this case Record size will be 8, HasAlignment flag is false.
1986   // 2) Record has artificial tag (Record[1]),
1987   //   has no obsolete inlignedAt field (Record[9]).
1988   //   In this case Record size will be 9, HasAlignment flag is false.
1989   // 3) Record has both artificial tag (Record[1]) and
1990   //   obsolete inlignedAt field (Record[9]).
1991   //   In this case Record size will be 10, HasAlignment flag is false.
1992   // 4) Record has neither artificial tag, nor inlignedAt field, but
1993   //   HasAlignment flag is true and Record[8] contains alignment value.
1994   const uint64_t HasAlignmentFlag = 1 << 1;
1995   Record.push_back((uint64_t)N->isDistinct() | HasAlignmentFlag);
1996   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1997   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1998   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1999   Record.push_back(N->getLine());
2000   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2001   Record.push_back(N->getArg());
2002   Record.push_back(N->getFlags());
2003   Record.push_back(N->getAlignInBits());
2004   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
2005 
2006   Stream.EmitRecord(bitc::METADATA_LOCAL_VAR, Record, Abbrev);
2007   Record.clear();
2008 }
2009 
2010 void ModuleBitcodeWriter::writeDILabel(
2011     const DILabel *N, SmallVectorImpl<uint64_t> &Record,
2012     unsigned Abbrev) {
2013   Record.push_back((uint64_t)N->isDistinct());
2014   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2015   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2016   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2017   Record.push_back(N->getLine());
2018 
2019   Stream.EmitRecord(bitc::METADATA_LABEL, Record, Abbrev);
2020   Record.clear();
2021 }
2022 
2023 void ModuleBitcodeWriter::writeDIExpression(const DIExpression *N,
2024                                             SmallVectorImpl<uint64_t> &Record,
2025                                             unsigned Abbrev) {
2026   Record.reserve(N->getElements().size() + 1);
2027   const uint64_t Version = 3 << 1;
2028   Record.push_back((uint64_t)N->isDistinct() | Version);
2029   Record.append(N->elements_begin(), N->elements_end());
2030 
2031   Stream.EmitRecord(bitc::METADATA_EXPRESSION, Record, Abbrev);
2032   Record.clear();
2033 }
2034 
2035 void ModuleBitcodeWriter::writeDIGlobalVariableExpression(
2036     const DIGlobalVariableExpression *N, SmallVectorImpl<uint64_t> &Record,
2037     unsigned Abbrev) {
2038   Record.push_back(N->isDistinct());
2039   Record.push_back(VE.getMetadataOrNullID(N->getVariable()));
2040   Record.push_back(VE.getMetadataOrNullID(N->getExpression()));
2041 
2042   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR_EXPR, Record, Abbrev);
2043   Record.clear();
2044 }
2045 
2046 void ModuleBitcodeWriter::writeDIObjCProperty(const DIObjCProperty *N,
2047                                               SmallVectorImpl<uint64_t> &Record,
2048                                               unsigned Abbrev) {
2049   Record.push_back(N->isDistinct());
2050   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2051   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2052   Record.push_back(N->getLine());
2053   Record.push_back(VE.getMetadataOrNullID(N->getRawSetterName()));
2054   Record.push_back(VE.getMetadataOrNullID(N->getRawGetterName()));
2055   Record.push_back(N->getAttributes());
2056   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2057 
2058   Stream.EmitRecord(bitc::METADATA_OBJC_PROPERTY, Record, Abbrev);
2059   Record.clear();
2060 }
2061 
2062 void ModuleBitcodeWriter::writeDIImportedEntity(
2063     const DIImportedEntity *N, SmallVectorImpl<uint64_t> &Record,
2064     unsigned Abbrev) {
2065   Record.push_back(N->isDistinct());
2066   Record.push_back(N->getTag());
2067   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2068   Record.push_back(VE.getMetadataOrNullID(N->getEntity()));
2069   Record.push_back(N->getLine());
2070   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2071   Record.push_back(VE.getMetadataOrNullID(N->getRawFile()));
2072   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
2073 
2074   Stream.EmitRecord(bitc::METADATA_IMPORTED_ENTITY, Record, Abbrev);
2075   Record.clear();
2076 }
2077 
2078 unsigned ModuleBitcodeWriter::createNamedMetadataAbbrev() {
2079   auto Abbv = std::make_shared<BitCodeAbbrev>();
2080   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
2081   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2082   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2083   return Stream.EmitAbbrev(std::move(Abbv));
2084 }
2085 
2086 void ModuleBitcodeWriter::writeNamedMetadata(
2087     SmallVectorImpl<uint64_t> &Record) {
2088   if (M.named_metadata_empty())
2089     return;
2090 
2091   unsigned Abbrev = createNamedMetadataAbbrev();
2092   for (const NamedMDNode &NMD : M.named_metadata()) {
2093     // Write name.
2094     StringRef Str = NMD.getName();
2095     Record.append(Str.bytes_begin(), Str.bytes_end());
2096     Stream.EmitRecord(bitc::METADATA_NAME, Record, Abbrev);
2097     Record.clear();
2098 
2099     // Write named metadata operands.
2100     for (const MDNode *N : NMD.operands())
2101       Record.push_back(VE.getMetadataID(N));
2102     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
2103     Record.clear();
2104   }
2105 }
2106 
2107 unsigned ModuleBitcodeWriter::createMetadataStringsAbbrev() {
2108   auto Abbv = std::make_shared<BitCodeAbbrev>();
2109   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRINGS));
2110   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // # of strings
2111   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // offset to chars
2112   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
2113   return Stream.EmitAbbrev(std::move(Abbv));
2114 }
2115 
2116 /// Write out a record for MDString.
2117 ///
2118 /// All the metadata strings in a metadata block are emitted in a single
2119 /// record.  The sizes and strings themselves are shoved into a blob.
2120 void ModuleBitcodeWriter::writeMetadataStrings(
2121     ArrayRef<const Metadata *> Strings, SmallVectorImpl<uint64_t> &Record) {
2122   if (Strings.empty())
2123     return;
2124 
2125   // Start the record with the number of strings.
2126   Record.push_back(bitc::METADATA_STRINGS);
2127   Record.push_back(Strings.size());
2128 
2129   // Emit the sizes of the strings in the blob.
2130   SmallString<256> Blob;
2131   {
2132     BitstreamWriter W(Blob);
2133     for (const Metadata *MD : Strings)
2134       W.EmitVBR(cast<MDString>(MD)->getLength(), 6);
2135     W.FlushToWord();
2136   }
2137 
2138   // Add the offset to the strings to the record.
2139   Record.push_back(Blob.size());
2140 
2141   // Add the strings to the blob.
2142   for (const Metadata *MD : Strings)
2143     Blob.append(cast<MDString>(MD)->getString());
2144 
2145   // Emit the final record.
2146   Stream.EmitRecordWithBlob(createMetadataStringsAbbrev(), Record, Blob);
2147   Record.clear();
2148 }
2149 
2150 // Generates an enum to use as an index in the Abbrev array of Metadata record.
2151 enum MetadataAbbrev : unsigned {
2152 #define HANDLE_MDNODE_LEAF(CLASS) CLASS##AbbrevID,
2153 #include "llvm/IR/Metadata.def"
2154   LastPlusOne
2155 };
2156 
2157 void ModuleBitcodeWriter::writeMetadataRecords(
2158     ArrayRef<const Metadata *> MDs, SmallVectorImpl<uint64_t> &Record,
2159     std::vector<unsigned> *MDAbbrevs, std::vector<uint64_t> *IndexPos) {
2160   if (MDs.empty())
2161     return;
2162 
2163   // Initialize MDNode abbreviations.
2164 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
2165 #include "llvm/IR/Metadata.def"
2166 
2167   for (const Metadata *MD : MDs) {
2168     if (IndexPos)
2169       IndexPos->push_back(Stream.GetCurrentBitNo());
2170     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
2171       assert(N->isResolved() && "Expected forward references to be resolved");
2172 
2173       switch (N->getMetadataID()) {
2174       default:
2175         llvm_unreachable("Invalid MDNode subclass");
2176 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
2177   case Metadata::CLASS##Kind:                                                  \
2178     if (MDAbbrevs)                                                             \
2179       write##CLASS(cast<CLASS>(N), Record,                                     \
2180                    (*MDAbbrevs)[MetadataAbbrev::CLASS##AbbrevID]);             \
2181     else                                                                       \
2182       write##CLASS(cast<CLASS>(N), Record, CLASS##Abbrev);                     \
2183     continue;
2184 #include "llvm/IR/Metadata.def"
2185       }
2186     }
2187     writeValueAsMetadata(cast<ValueAsMetadata>(MD), Record);
2188   }
2189 }
2190 
2191 void ModuleBitcodeWriter::writeModuleMetadata() {
2192   if (!VE.hasMDs() && M.named_metadata_empty())
2193     return;
2194 
2195   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 4);
2196   SmallVector<uint64_t, 64> Record;
2197 
2198   // Emit all abbrevs upfront, so that the reader can jump in the middle of the
2199   // block and load any metadata.
2200   std::vector<unsigned> MDAbbrevs;
2201 
2202   MDAbbrevs.resize(MetadataAbbrev::LastPlusOne);
2203   MDAbbrevs[MetadataAbbrev::DILocationAbbrevID] = createDILocationAbbrev();
2204   MDAbbrevs[MetadataAbbrev::GenericDINodeAbbrevID] =
2205       createGenericDINodeAbbrev();
2206 
2207   auto Abbv = std::make_shared<BitCodeAbbrev>();
2208   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX_OFFSET));
2209   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2210   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2211   unsigned OffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2212 
2213   Abbv = std::make_shared<BitCodeAbbrev>();
2214   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX));
2215   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2216   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2217   unsigned IndexAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2218 
2219   // Emit MDStrings together upfront.
2220   writeMetadataStrings(VE.getMDStrings(), Record);
2221 
2222   // We only emit an index for the metadata record if we have more than a given
2223   // (naive) threshold of metadatas, otherwise it is not worth it.
2224   if (VE.getNonMDStrings().size() > IndexThreshold) {
2225     // Write a placeholder value in for the offset of the metadata index,
2226     // which is written after the records, so that it can include
2227     // the offset of each entry. The placeholder offset will be
2228     // updated after all records are emitted.
2229     uint64_t Vals[] = {0, 0};
2230     Stream.EmitRecord(bitc::METADATA_INDEX_OFFSET, Vals, OffsetAbbrev);
2231   }
2232 
2233   // Compute and save the bit offset to the current position, which will be
2234   // patched when we emit the index later. We can simply subtract the 64-bit
2235   // fixed size from the current bit number to get the location to backpatch.
2236   uint64_t IndexOffsetRecordBitPos = Stream.GetCurrentBitNo();
2237 
2238   // This index will contain the bitpos for each individual record.
2239   std::vector<uint64_t> IndexPos;
2240   IndexPos.reserve(VE.getNonMDStrings().size());
2241 
2242   // Write all the records
2243   writeMetadataRecords(VE.getNonMDStrings(), Record, &MDAbbrevs, &IndexPos);
2244 
2245   if (VE.getNonMDStrings().size() > IndexThreshold) {
2246     // Now that we have emitted all the records we will emit the index. But
2247     // first
2248     // backpatch the forward reference so that the reader can skip the records
2249     // efficiently.
2250     Stream.BackpatchWord64(IndexOffsetRecordBitPos - 64,
2251                            Stream.GetCurrentBitNo() - IndexOffsetRecordBitPos);
2252 
2253     // Delta encode the index.
2254     uint64_t PreviousValue = IndexOffsetRecordBitPos;
2255     for (auto &Elt : IndexPos) {
2256       auto EltDelta = Elt - PreviousValue;
2257       PreviousValue = Elt;
2258       Elt = EltDelta;
2259     }
2260     // Emit the index record.
2261     Stream.EmitRecord(bitc::METADATA_INDEX, IndexPos, IndexAbbrev);
2262     IndexPos.clear();
2263   }
2264 
2265   // Write the named metadata now.
2266   writeNamedMetadata(Record);
2267 
2268   auto AddDeclAttachedMetadata = [&](const GlobalObject &GO) {
2269     SmallVector<uint64_t, 4> Record;
2270     Record.push_back(VE.getValueID(&GO));
2271     pushGlobalMetadataAttachment(Record, GO);
2272     Stream.EmitRecord(bitc::METADATA_GLOBAL_DECL_ATTACHMENT, Record);
2273   };
2274   for (const Function &F : M)
2275     if (F.isDeclaration() && F.hasMetadata())
2276       AddDeclAttachedMetadata(F);
2277   // FIXME: Only store metadata for declarations here, and move data for global
2278   // variable definitions to a separate block (PR28134).
2279   for (const GlobalVariable &GV : M.globals())
2280     if (GV.hasMetadata())
2281       AddDeclAttachedMetadata(GV);
2282 
2283   Stream.ExitBlock();
2284 }
2285 
2286 void ModuleBitcodeWriter::writeFunctionMetadata(const Function &F) {
2287   if (!VE.hasMDs())
2288     return;
2289 
2290   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
2291   SmallVector<uint64_t, 64> Record;
2292   writeMetadataStrings(VE.getMDStrings(), Record);
2293   writeMetadataRecords(VE.getNonMDStrings(), Record);
2294   Stream.ExitBlock();
2295 }
2296 
2297 void ModuleBitcodeWriter::pushGlobalMetadataAttachment(
2298     SmallVectorImpl<uint64_t> &Record, const GlobalObject &GO) {
2299   // [n x [id, mdnode]]
2300   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2301   GO.getAllMetadata(MDs);
2302   for (const auto &I : MDs) {
2303     Record.push_back(I.first);
2304     Record.push_back(VE.getMetadataID(I.second));
2305   }
2306 }
2307 
2308 void ModuleBitcodeWriter::writeFunctionMetadataAttachment(const Function &F) {
2309   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
2310 
2311   SmallVector<uint64_t, 64> Record;
2312 
2313   if (F.hasMetadata()) {
2314     pushGlobalMetadataAttachment(Record, F);
2315     Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2316     Record.clear();
2317   }
2318 
2319   // Write metadata attachments
2320   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
2321   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2322   for (const BasicBlock &BB : F)
2323     for (const Instruction &I : BB) {
2324       MDs.clear();
2325       I.getAllMetadataOtherThanDebugLoc(MDs);
2326 
2327       // If no metadata, ignore instruction.
2328       if (MDs.empty()) continue;
2329 
2330       Record.push_back(VE.getInstructionID(&I));
2331 
2332       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
2333         Record.push_back(MDs[i].first);
2334         Record.push_back(VE.getMetadataID(MDs[i].second));
2335       }
2336       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2337       Record.clear();
2338     }
2339 
2340   Stream.ExitBlock();
2341 }
2342 
2343 void ModuleBitcodeWriter::writeModuleMetadataKinds() {
2344   SmallVector<uint64_t, 64> Record;
2345 
2346   // Write metadata kinds
2347   // METADATA_KIND - [n x [id, name]]
2348   SmallVector<StringRef, 8> Names;
2349   M.getMDKindNames(Names);
2350 
2351   if (Names.empty()) return;
2352 
2353   Stream.EnterSubblock(bitc::METADATA_KIND_BLOCK_ID, 3);
2354 
2355   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
2356     Record.push_back(MDKindID);
2357     StringRef KName = Names[MDKindID];
2358     Record.append(KName.begin(), KName.end());
2359 
2360     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
2361     Record.clear();
2362   }
2363 
2364   Stream.ExitBlock();
2365 }
2366 
2367 void ModuleBitcodeWriter::writeOperandBundleTags() {
2368   // Write metadata kinds
2369   //
2370   // OPERAND_BUNDLE_TAGS_BLOCK_ID : N x OPERAND_BUNDLE_TAG
2371   //
2372   // OPERAND_BUNDLE_TAG - [strchr x N]
2373 
2374   SmallVector<StringRef, 8> Tags;
2375   M.getOperandBundleTags(Tags);
2376 
2377   if (Tags.empty())
2378     return;
2379 
2380   Stream.EnterSubblock(bitc::OPERAND_BUNDLE_TAGS_BLOCK_ID, 3);
2381 
2382   SmallVector<uint64_t, 64> Record;
2383 
2384   for (auto Tag : Tags) {
2385     Record.append(Tag.begin(), Tag.end());
2386 
2387     Stream.EmitRecord(bitc::OPERAND_BUNDLE_TAG, Record, 0);
2388     Record.clear();
2389   }
2390 
2391   Stream.ExitBlock();
2392 }
2393 
2394 void ModuleBitcodeWriter::writeSyncScopeNames() {
2395   SmallVector<StringRef, 8> SSNs;
2396   M.getContext().getSyncScopeNames(SSNs);
2397   if (SSNs.empty())
2398     return;
2399 
2400   Stream.EnterSubblock(bitc::SYNC_SCOPE_NAMES_BLOCK_ID, 2);
2401 
2402   SmallVector<uint64_t, 64> Record;
2403   for (auto SSN : SSNs) {
2404     Record.append(SSN.begin(), SSN.end());
2405     Stream.EmitRecord(bitc::SYNC_SCOPE_NAME, Record, 0);
2406     Record.clear();
2407   }
2408 
2409   Stream.ExitBlock();
2410 }
2411 
2412 void ModuleBitcodeWriter::writeConstants(unsigned FirstVal, unsigned LastVal,
2413                                          bool isGlobal) {
2414   if (FirstVal == LastVal) return;
2415 
2416   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
2417 
2418   unsigned AggregateAbbrev = 0;
2419   unsigned String8Abbrev = 0;
2420   unsigned CString7Abbrev = 0;
2421   unsigned CString6Abbrev = 0;
2422   // If this is a constant pool for the module, emit module-specific abbrevs.
2423   if (isGlobal) {
2424     // Abbrev for CST_CODE_AGGREGATE.
2425     auto Abbv = std::make_shared<BitCodeAbbrev>();
2426     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
2427     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2428     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
2429     AggregateAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2430 
2431     // Abbrev for CST_CODE_STRING.
2432     Abbv = std::make_shared<BitCodeAbbrev>();
2433     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
2434     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2435     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2436     String8Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2437     // Abbrev for CST_CODE_CSTRING.
2438     Abbv = std::make_shared<BitCodeAbbrev>();
2439     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2440     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2441     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2442     CString7Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2443     // Abbrev for CST_CODE_CSTRING.
2444     Abbv = std::make_shared<BitCodeAbbrev>();
2445     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2446     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2447     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2448     CString6Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2449   }
2450 
2451   SmallVector<uint64_t, 64> Record;
2452 
2453   const ValueEnumerator::ValueList &Vals = VE.getValues();
2454   Type *LastTy = nullptr;
2455   for (unsigned i = FirstVal; i != LastVal; ++i) {
2456     const Value *V = Vals[i].first;
2457     // If we need to switch types, do so now.
2458     if (V->getType() != LastTy) {
2459       LastTy = V->getType();
2460       Record.push_back(VE.getTypeID(LastTy));
2461       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
2462                         CONSTANTS_SETTYPE_ABBREV);
2463       Record.clear();
2464     }
2465 
2466     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
2467       Record.push_back(VE.getTypeID(IA->getFunctionType()));
2468       Record.push_back(
2469           unsigned(IA->hasSideEffects()) | unsigned(IA->isAlignStack()) << 1 |
2470           unsigned(IA->getDialect() & 1) << 2 | unsigned(IA->canThrow()) << 3);
2471 
2472       // Add the asm string.
2473       const std::string &AsmStr = IA->getAsmString();
2474       Record.push_back(AsmStr.size());
2475       Record.append(AsmStr.begin(), AsmStr.end());
2476 
2477       // Add the constraint string.
2478       const std::string &ConstraintStr = IA->getConstraintString();
2479       Record.push_back(ConstraintStr.size());
2480       Record.append(ConstraintStr.begin(), ConstraintStr.end());
2481       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
2482       Record.clear();
2483       continue;
2484     }
2485     const Constant *C = cast<Constant>(V);
2486     unsigned Code = -1U;
2487     unsigned AbbrevToUse = 0;
2488     if (C->isNullValue()) {
2489       Code = bitc::CST_CODE_NULL;
2490     } else if (isa<PoisonValue>(C)) {
2491       Code = bitc::CST_CODE_POISON;
2492     } else if (isa<UndefValue>(C)) {
2493       Code = bitc::CST_CODE_UNDEF;
2494     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
2495       if (IV->getBitWidth() <= 64) {
2496         uint64_t V = IV->getSExtValue();
2497         emitSignedInt64(Record, V);
2498         Code = bitc::CST_CODE_INTEGER;
2499         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
2500       } else {                             // Wide integers, > 64 bits in size.
2501         emitWideAPInt(Record, IV->getValue());
2502         Code = bitc::CST_CODE_WIDE_INTEGER;
2503       }
2504     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
2505       Code = bitc::CST_CODE_FLOAT;
2506       Type *Ty = CFP->getType();
2507       if (Ty->isHalfTy() || Ty->isBFloatTy() || Ty->isFloatTy() ||
2508           Ty->isDoubleTy()) {
2509         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
2510       } else if (Ty->isX86_FP80Ty()) {
2511         // api needed to prevent premature destruction
2512         // bits are not in the same order as a normal i80 APInt, compensate.
2513         APInt api = CFP->getValueAPF().bitcastToAPInt();
2514         const uint64_t *p = api.getRawData();
2515         Record.push_back((p[1] << 48) | (p[0] >> 16));
2516         Record.push_back(p[0] & 0xffffLL);
2517       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
2518         APInt api = CFP->getValueAPF().bitcastToAPInt();
2519         const uint64_t *p = api.getRawData();
2520         Record.push_back(p[0]);
2521         Record.push_back(p[1]);
2522       } else {
2523         assert(0 && "Unknown FP type!");
2524       }
2525     } else if (isa<ConstantDataSequential>(C) &&
2526                cast<ConstantDataSequential>(C)->isString()) {
2527       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
2528       // Emit constant strings specially.
2529       unsigned NumElts = Str->getNumElements();
2530       // If this is a null-terminated string, use the denser CSTRING encoding.
2531       if (Str->isCString()) {
2532         Code = bitc::CST_CODE_CSTRING;
2533         --NumElts;  // Don't encode the null, which isn't allowed by char6.
2534       } else {
2535         Code = bitc::CST_CODE_STRING;
2536         AbbrevToUse = String8Abbrev;
2537       }
2538       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
2539       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
2540       for (unsigned i = 0; i != NumElts; ++i) {
2541         unsigned char V = Str->getElementAsInteger(i);
2542         Record.push_back(V);
2543         isCStr7 &= (V & 128) == 0;
2544         if (isCStrChar6)
2545           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
2546       }
2547 
2548       if (isCStrChar6)
2549         AbbrevToUse = CString6Abbrev;
2550       else if (isCStr7)
2551         AbbrevToUse = CString7Abbrev;
2552     } else if (const ConstantDataSequential *CDS =
2553                   dyn_cast<ConstantDataSequential>(C)) {
2554       Code = bitc::CST_CODE_DATA;
2555       Type *EltTy = CDS->getElementType();
2556       if (isa<IntegerType>(EltTy)) {
2557         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2558           Record.push_back(CDS->getElementAsInteger(i));
2559       } else {
2560         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2561           Record.push_back(
2562               CDS->getElementAsAPFloat(i).bitcastToAPInt().getLimitedValue());
2563       }
2564     } else if (isa<ConstantAggregate>(C)) {
2565       Code = bitc::CST_CODE_AGGREGATE;
2566       for (const Value *Op : C->operands())
2567         Record.push_back(VE.getValueID(Op));
2568       AbbrevToUse = AggregateAbbrev;
2569     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
2570       switch (CE->getOpcode()) {
2571       default:
2572         if (Instruction::isCast(CE->getOpcode())) {
2573           Code = bitc::CST_CODE_CE_CAST;
2574           Record.push_back(getEncodedCastOpcode(CE->getOpcode()));
2575           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2576           Record.push_back(VE.getValueID(C->getOperand(0)));
2577           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
2578         } else {
2579           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
2580           Code = bitc::CST_CODE_CE_BINOP;
2581           Record.push_back(getEncodedBinaryOpcode(CE->getOpcode()));
2582           Record.push_back(VE.getValueID(C->getOperand(0)));
2583           Record.push_back(VE.getValueID(C->getOperand(1)));
2584           uint64_t Flags = getOptimizationFlags(CE);
2585           if (Flags != 0)
2586             Record.push_back(Flags);
2587         }
2588         break;
2589       case Instruction::FNeg: {
2590         assert(CE->getNumOperands() == 1 && "Unknown constant expr!");
2591         Code = bitc::CST_CODE_CE_UNOP;
2592         Record.push_back(getEncodedUnaryOpcode(CE->getOpcode()));
2593         Record.push_back(VE.getValueID(C->getOperand(0)));
2594         uint64_t Flags = getOptimizationFlags(CE);
2595         if (Flags != 0)
2596           Record.push_back(Flags);
2597         break;
2598       }
2599       case Instruction::GetElementPtr: {
2600         Code = bitc::CST_CODE_CE_GEP;
2601         const auto *GO = cast<GEPOperator>(C);
2602         Record.push_back(VE.getTypeID(GO->getSourceElementType()));
2603         if (Optional<unsigned> Idx = GO->getInRangeIndex()) {
2604           Code = bitc::CST_CODE_CE_GEP_WITH_INRANGE_INDEX;
2605           Record.push_back((*Idx << 1) | GO->isInBounds());
2606         } else if (GO->isInBounds())
2607           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
2608         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
2609           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
2610           Record.push_back(VE.getValueID(C->getOperand(i)));
2611         }
2612         break;
2613       }
2614       case Instruction::Select:
2615         Code = bitc::CST_CODE_CE_SELECT;
2616         Record.push_back(VE.getValueID(C->getOperand(0)));
2617         Record.push_back(VE.getValueID(C->getOperand(1)));
2618         Record.push_back(VE.getValueID(C->getOperand(2)));
2619         break;
2620       case Instruction::ExtractElement:
2621         Code = bitc::CST_CODE_CE_EXTRACTELT;
2622         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2623         Record.push_back(VE.getValueID(C->getOperand(0)));
2624         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
2625         Record.push_back(VE.getValueID(C->getOperand(1)));
2626         break;
2627       case Instruction::InsertElement:
2628         Code = bitc::CST_CODE_CE_INSERTELT;
2629         Record.push_back(VE.getValueID(C->getOperand(0)));
2630         Record.push_back(VE.getValueID(C->getOperand(1)));
2631         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
2632         Record.push_back(VE.getValueID(C->getOperand(2)));
2633         break;
2634       case Instruction::ShuffleVector:
2635         // If the return type and argument types are the same, this is a
2636         // standard shufflevector instruction.  If the types are different,
2637         // then the shuffle is widening or truncating the input vectors, and
2638         // the argument type must also be encoded.
2639         if (C->getType() == C->getOperand(0)->getType()) {
2640           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
2641         } else {
2642           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
2643           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2644         }
2645         Record.push_back(VE.getValueID(C->getOperand(0)));
2646         Record.push_back(VE.getValueID(C->getOperand(1)));
2647         Record.push_back(VE.getValueID(CE->getShuffleMaskForBitcode()));
2648         break;
2649       case Instruction::ICmp:
2650       case Instruction::FCmp:
2651         Code = bitc::CST_CODE_CE_CMP;
2652         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2653         Record.push_back(VE.getValueID(C->getOperand(0)));
2654         Record.push_back(VE.getValueID(C->getOperand(1)));
2655         Record.push_back(CE->getPredicate());
2656         break;
2657       case Instruction::ExtractValue:
2658       case Instruction::InsertValue:
2659         report_fatal_error("extractvalue/insertvalue constexprs not supported");
2660         break;
2661       }
2662     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
2663       Code = bitc::CST_CODE_BLOCKADDRESS;
2664       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
2665       Record.push_back(VE.getValueID(BA->getFunction()));
2666       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
2667     } else if (const auto *Equiv = dyn_cast<DSOLocalEquivalent>(C)) {
2668       Code = bitc::CST_CODE_DSO_LOCAL_EQUIVALENT;
2669       Record.push_back(VE.getTypeID(Equiv->getGlobalValue()->getType()));
2670       Record.push_back(VE.getValueID(Equiv->getGlobalValue()));
2671     } else if (const auto *NC = dyn_cast<NoCFIValue>(C)) {
2672       Code = bitc::CST_CODE_NO_CFI_VALUE;
2673       Record.push_back(VE.getTypeID(NC->getGlobalValue()->getType()));
2674       Record.push_back(VE.getValueID(NC->getGlobalValue()));
2675     } else {
2676 #ifndef NDEBUG
2677       C->dump();
2678 #endif
2679       llvm_unreachable("Unknown constant!");
2680     }
2681     Stream.EmitRecord(Code, Record, AbbrevToUse);
2682     Record.clear();
2683   }
2684 
2685   Stream.ExitBlock();
2686 }
2687 
2688 void ModuleBitcodeWriter::writeModuleConstants() {
2689   const ValueEnumerator::ValueList &Vals = VE.getValues();
2690 
2691   // Find the first constant to emit, which is the first non-globalvalue value.
2692   // We know globalvalues have been emitted by WriteModuleInfo.
2693   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
2694     if (!isa<GlobalValue>(Vals[i].first)) {
2695       writeConstants(i, Vals.size(), true);
2696       return;
2697     }
2698   }
2699 }
2700 
2701 /// pushValueAndType - The file has to encode both the value and type id for
2702 /// many values, because we need to know what type to create for forward
2703 /// references.  However, most operands are not forward references, so this type
2704 /// field is not needed.
2705 ///
2706 /// This function adds V's value ID to Vals.  If the value ID is higher than the
2707 /// instruction ID, then it is a forward reference, and it also includes the
2708 /// type ID.  The value ID that is written is encoded relative to the InstID.
2709 bool ModuleBitcodeWriter::pushValueAndType(const Value *V, unsigned InstID,
2710                                            SmallVectorImpl<unsigned> &Vals) {
2711   unsigned ValID = VE.getValueID(V);
2712   // Make encoding relative to the InstID.
2713   Vals.push_back(InstID - ValID);
2714   if (ValID >= InstID) {
2715     Vals.push_back(VE.getTypeID(V->getType()));
2716     return true;
2717   }
2718   return false;
2719 }
2720 
2721 void ModuleBitcodeWriter::writeOperandBundles(const CallBase &CS,
2722                                               unsigned InstID) {
2723   SmallVector<unsigned, 64> Record;
2724   LLVMContext &C = CS.getContext();
2725 
2726   for (unsigned i = 0, e = CS.getNumOperandBundles(); i != e; ++i) {
2727     const auto &Bundle = CS.getOperandBundleAt(i);
2728     Record.push_back(C.getOperandBundleTagID(Bundle.getTagName()));
2729 
2730     for (auto &Input : Bundle.Inputs)
2731       pushValueAndType(Input, InstID, Record);
2732 
2733     Stream.EmitRecord(bitc::FUNC_CODE_OPERAND_BUNDLE, Record);
2734     Record.clear();
2735   }
2736 }
2737 
2738 /// pushValue - Like pushValueAndType, but where the type of the value is
2739 /// omitted (perhaps it was already encoded in an earlier operand).
2740 void ModuleBitcodeWriter::pushValue(const Value *V, unsigned InstID,
2741                                     SmallVectorImpl<unsigned> &Vals) {
2742   unsigned ValID = VE.getValueID(V);
2743   Vals.push_back(InstID - ValID);
2744 }
2745 
2746 void ModuleBitcodeWriter::pushValueSigned(const Value *V, unsigned InstID,
2747                                           SmallVectorImpl<uint64_t> &Vals) {
2748   unsigned ValID = VE.getValueID(V);
2749   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
2750   emitSignedInt64(Vals, diff);
2751 }
2752 
2753 /// WriteInstruction - Emit an instruction to the specified stream.
2754 void ModuleBitcodeWriter::writeInstruction(const Instruction &I,
2755                                            unsigned InstID,
2756                                            SmallVectorImpl<unsigned> &Vals) {
2757   unsigned Code = 0;
2758   unsigned AbbrevToUse = 0;
2759   VE.setInstructionID(&I);
2760   switch (I.getOpcode()) {
2761   default:
2762     if (Instruction::isCast(I.getOpcode())) {
2763       Code = bitc::FUNC_CODE_INST_CAST;
2764       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2765         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
2766       Vals.push_back(VE.getTypeID(I.getType()));
2767       Vals.push_back(getEncodedCastOpcode(I.getOpcode()));
2768     } else {
2769       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
2770       Code = bitc::FUNC_CODE_INST_BINOP;
2771       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2772         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
2773       pushValue(I.getOperand(1), InstID, Vals);
2774       Vals.push_back(getEncodedBinaryOpcode(I.getOpcode()));
2775       uint64_t Flags = getOptimizationFlags(&I);
2776       if (Flags != 0) {
2777         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
2778           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
2779         Vals.push_back(Flags);
2780       }
2781     }
2782     break;
2783   case Instruction::FNeg: {
2784     Code = bitc::FUNC_CODE_INST_UNOP;
2785     if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2786       AbbrevToUse = FUNCTION_INST_UNOP_ABBREV;
2787     Vals.push_back(getEncodedUnaryOpcode(I.getOpcode()));
2788     uint64_t Flags = getOptimizationFlags(&I);
2789     if (Flags != 0) {
2790       if (AbbrevToUse == FUNCTION_INST_UNOP_ABBREV)
2791         AbbrevToUse = FUNCTION_INST_UNOP_FLAGS_ABBREV;
2792       Vals.push_back(Flags);
2793     }
2794     break;
2795   }
2796   case Instruction::GetElementPtr: {
2797     Code = bitc::FUNC_CODE_INST_GEP;
2798     AbbrevToUse = FUNCTION_INST_GEP_ABBREV;
2799     auto &GEPInst = cast<GetElementPtrInst>(I);
2800     Vals.push_back(GEPInst.isInBounds());
2801     Vals.push_back(VE.getTypeID(GEPInst.getSourceElementType()));
2802     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
2803       pushValueAndType(I.getOperand(i), InstID, Vals);
2804     break;
2805   }
2806   case Instruction::ExtractValue: {
2807     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
2808     pushValueAndType(I.getOperand(0), InstID, Vals);
2809     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
2810     Vals.append(EVI->idx_begin(), EVI->idx_end());
2811     break;
2812   }
2813   case Instruction::InsertValue: {
2814     Code = bitc::FUNC_CODE_INST_INSERTVAL;
2815     pushValueAndType(I.getOperand(0), InstID, Vals);
2816     pushValueAndType(I.getOperand(1), InstID, Vals);
2817     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
2818     Vals.append(IVI->idx_begin(), IVI->idx_end());
2819     break;
2820   }
2821   case Instruction::Select: {
2822     Code = bitc::FUNC_CODE_INST_VSELECT;
2823     pushValueAndType(I.getOperand(1), InstID, Vals);
2824     pushValue(I.getOperand(2), InstID, Vals);
2825     pushValueAndType(I.getOperand(0), InstID, Vals);
2826     uint64_t Flags = getOptimizationFlags(&I);
2827     if (Flags != 0)
2828       Vals.push_back(Flags);
2829     break;
2830   }
2831   case Instruction::ExtractElement:
2832     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
2833     pushValueAndType(I.getOperand(0), InstID, Vals);
2834     pushValueAndType(I.getOperand(1), InstID, Vals);
2835     break;
2836   case Instruction::InsertElement:
2837     Code = bitc::FUNC_CODE_INST_INSERTELT;
2838     pushValueAndType(I.getOperand(0), InstID, Vals);
2839     pushValue(I.getOperand(1), InstID, Vals);
2840     pushValueAndType(I.getOperand(2), InstID, Vals);
2841     break;
2842   case Instruction::ShuffleVector:
2843     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
2844     pushValueAndType(I.getOperand(0), InstID, Vals);
2845     pushValue(I.getOperand(1), InstID, Vals);
2846     pushValue(cast<ShuffleVectorInst>(I).getShuffleMaskForBitcode(), InstID,
2847               Vals);
2848     break;
2849   case Instruction::ICmp:
2850   case Instruction::FCmp: {
2851     // compare returning Int1Ty or vector of Int1Ty
2852     Code = bitc::FUNC_CODE_INST_CMP2;
2853     pushValueAndType(I.getOperand(0), InstID, Vals);
2854     pushValue(I.getOperand(1), InstID, Vals);
2855     Vals.push_back(cast<CmpInst>(I).getPredicate());
2856     uint64_t Flags = getOptimizationFlags(&I);
2857     if (Flags != 0)
2858       Vals.push_back(Flags);
2859     break;
2860   }
2861 
2862   case Instruction::Ret:
2863     {
2864       Code = bitc::FUNC_CODE_INST_RET;
2865       unsigned NumOperands = I.getNumOperands();
2866       if (NumOperands == 0)
2867         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
2868       else if (NumOperands == 1) {
2869         if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2870           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
2871       } else {
2872         for (unsigned i = 0, e = NumOperands; i != e; ++i)
2873           pushValueAndType(I.getOperand(i), InstID, Vals);
2874       }
2875     }
2876     break;
2877   case Instruction::Br:
2878     {
2879       Code = bitc::FUNC_CODE_INST_BR;
2880       const BranchInst &II = cast<BranchInst>(I);
2881       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
2882       if (II.isConditional()) {
2883         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
2884         pushValue(II.getCondition(), InstID, Vals);
2885       }
2886     }
2887     break;
2888   case Instruction::Switch:
2889     {
2890       Code = bitc::FUNC_CODE_INST_SWITCH;
2891       const SwitchInst &SI = cast<SwitchInst>(I);
2892       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
2893       pushValue(SI.getCondition(), InstID, Vals);
2894       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
2895       for (auto Case : SI.cases()) {
2896         Vals.push_back(VE.getValueID(Case.getCaseValue()));
2897         Vals.push_back(VE.getValueID(Case.getCaseSuccessor()));
2898       }
2899     }
2900     break;
2901   case Instruction::IndirectBr:
2902     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
2903     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2904     // Encode the address operand as relative, but not the basic blocks.
2905     pushValue(I.getOperand(0), InstID, Vals);
2906     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
2907       Vals.push_back(VE.getValueID(I.getOperand(i)));
2908     break;
2909 
2910   case Instruction::Invoke: {
2911     const InvokeInst *II = cast<InvokeInst>(&I);
2912     const Value *Callee = II->getCalledOperand();
2913     FunctionType *FTy = II->getFunctionType();
2914 
2915     if (II->hasOperandBundles())
2916       writeOperandBundles(*II, InstID);
2917 
2918     Code = bitc::FUNC_CODE_INST_INVOKE;
2919 
2920     Vals.push_back(VE.getAttributeListID(II->getAttributes()));
2921     Vals.push_back(II->getCallingConv() | 1 << 13);
2922     Vals.push_back(VE.getValueID(II->getNormalDest()));
2923     Vals.push_back(VE.getValueID(II->getUnwindDest()));
2924     Vals.push_back(VE.getTypeID(FTy));
2925     pushValueAndType(Callee, InstID, Vals);
2926 
2927     // Emit value #'s for the fixed parameters.
2928     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
2929       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
2930 
2931     // Emit type/value pairs for varargs params.
2932     if (FTy->isVarArg()) {
2933       for (unsigned i = FTy->getNumParams(), e = II->arg_size(); i != e; ++i)
2934         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
2935     }
2936     break;
2937   }
2938   case Instruction::Resume:
2939     Code = bitc::FUNC_CODE_INST_RESUME;
2940     pushValueAndType(I.getOperand(0), InstID, Vals);
2941     break;
2942   case Instruction::CleanupRet: {
2943     Code = bitc::FUNC_CODE_INST_CLEANUPRET;
2944     const auto &CRI = cast<CleanupReturnInst>(I);
2945     pushValue(CRI.getCleanupPad(), InstID, Vals);
2946     if (CRI.hasUnwindDest())
2947       Vals.push_back(VE.getValueID(CRI.getUnwindDest()));
2948     break;
2949   }
2950   case Instruction::CatchRet: {
2951     Code = bitc::FUNC_CODE_INST_CATCHRET;
2952     const auto &CRI = cast<CatchReturnInst>(I);
2953     pushValue(CRI.getCatchPad(), InstID, Vals);
2954     Vals.push_back(VE.getValueID(CRI.getSuccessor()));
2955     break;
2956   }
2957   case Instruction::CleanupPad:
2958   case Instruction::CatchPad: {
2959     const auto &FuncletPad = cast<FuncletPadInst>(I);
2960     Code = isa<CatchPadInst>(FuncletPad) ? bitc::FUNC_CODE_INST_CATCHPAD
2961                                          : bitc::FUNC_CODE_INST_CLEANUPPAD;
2962     pushValue(FuncletPad.getParentPad(), InstID, Vals);
2963 
2964     unsigned NumArgOperands = FuncletPad.getNumArgOperands();
2965     Vals.push_back(NumArgOperands);
2966     for (unsigned Op = 0; Op != NumArgOperands; ++Op)
2967       pushValueAndType(FuncletPad.getArgOperand(Op), InstID, Vals);
2968     break;
2969   }
2970   case Instruction::CatchSwitch: {
2971     Code = bitc::FUNC_CODE_INST_CATCHSWITCH;
2972     const auto &CatchSwitch = cast<CatchSwitchInst>(I);
2973 
2974     pushValue(CatchSwitch.getParentPad(), InstID, Vals);
2975 
2976     unsigned NumHandlers = CatchSwitch.getNumHandlers();
2977     Vals.push_back(NumHandlers);
2978     for (const BasicBlock *CatchPadBB : CatchSwitch.handlers())
2979       Vals.push_back(VE.getValueID(CatchPadBB));
2980 
2981     if (CatchSwitch.hasUnwindDest())
2982       Vals.push_back(VE.getValueID(CatchSwitch.getUnwindDest()));
2983     break;
2984   }
2985   case Instruction::CallBr: {
2986     const CallBrInst *CBI = cast<CallBrInst>(&I);
2987     const Value *Callee = CBI->getCalledOperand();
2988     FunctionType *FTy = CBI->getFunctionType();
2989 
2990     if (CBI->hasOperandBundles())
2991       writeOperandBundles(*CBI, InstID);
2992 
2993     Code = bitc::FUNC_CODE_INST_CALLBR;
2994 
2995     Vals.push_back(VE.getAttributeListID(CBI->getAttributes()));
2996 
2997     Vals.push_back(CBI->getCallingConv() << bitc::CALL_CCONV |
2998                    1 << bitc::CALL_EXPLICIT_TYPE);
2999 
3000     Vals.push_back(VE.getValueID(CBI->getDefaultDest()));
3001     Vals.push_back(CBI->getNumIndirectDests());
3002     for (unsigned i = 0, e = CBI->getNumIndirectDests(); i != e; ++i)
3003       Vals.push_back(VE.getValueID(CBI->getIndirectDest(i)));
3004 
3005     Vals.push_back(VE.getTypeID(FTy));
3006     pushValueAndType(Callee, InstID, Vals);
3007 
3008     // Emit value #'s for the fixed parameters.
3009     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
3010       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
3011 
3012     // Emit type/value pairs for varargs params.
3013     if (FTy->isVarArg()) {
3014       for (unsigned i = FTy->getNumParams(), e = CBI->arg_size(); i != e; ++i)
3015         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
3016     }
3017     break;
3018   }
3019   case Instruction::Unreachable:
3020     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
3021     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
3022     break;
3023 
3024   case Instruction::PHI: {
3025     const PHINode &PN = cast<PHINode>(I);
3026     Code = bitc::FUNC_CODE_INST_PHI;
3027     // With the newer instruction encoding, forward references could give
3028     // negative valued IDs.  This is most common for PHIs, so we use
3029     // signed VBRs.
3030     SmallVector<uint64_t, 128> Vals64;
3031     Vals64.push_back(VE.getTypeID(PN.getType()));
3032     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
3033       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64);
3034       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
3035     }
3036 
3037     uint64_t Flags = getOptimizationFlags(&I);
3038     if (Flags != 0)
3039       Vals64.push_back(Flags);
3040 
3041     // Emit a Vals64 vector and exit.
3042     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
3043     Vals64.clear();
3044     return;
3045   }
3046 
3047   case Instruction::LandingPad: {
3048     const LandingPadInst &LP = cast<LandingPadInst>(I);
3049     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
3050     Vals.push_back(VE.getTypeID(LP.getType()));
3051     Vals.push_back(LP.isCleanup());
3052     Vals.push_back(LP.getNumClauses());
3053     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
3054       if (LP.isCatch(I))
3055         Vals.push_back(LandingPadInst::Catch);
3056       else
3057         Vals.push_back(LandingPadInst::Filter);
3058       pushValueAndType(LP.getClause(I), InstID, Vals);
3059     }
3060     break;
3061   }
3062 
3063   case Instruction::Alloca: {
3064     Code = bitc::FUNC_CODE_INST_ALLOCA;
3065     const AllocaInst &AI = cast<AllocaInst>(I);
3066     Vals.push_back(VE.getTypeID(AI.getAllocatedType()));
3067     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
3068     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
3069     using APV = AllocaPackedValues;
3070     unsigned Record = 0;
3071     unsigned EncodedAlign = getEncodedAlign(AI.getAlign());
3072     Bitfield::set<APV::AlignLower>(
3073         Record, EncodedAlign & ((1 << APV::AlignLower::Bits) - 1));
3074     Bitfield::set<APV::AlignUpper>(Record,
3075                                    EncodedAlign >> APV::AlignLower::Bits);
3076     Bitfield::set<APV::UsedWithInAlloca>(Record, AI.isUsedWithInAlloca());
3077     Bitfield::set<APV::ExplicitType>(Record, true);
3078     Bitfield::set<APV::SwiftError>(Record, AI.isSwiftError());
3079     Vals.push_back(Record);
3080 
3081     unsigned AS = AI.getAddressSpace();
3082     if (AS != M.getDataLayout().getAllocaAddrSpace())
3083       Vals.push_back(AS);
3084     break;
3085   }
3086 
3087   case Instruction::Load:
3088     if (cast<LoadInst>(I).isAtomic()) {
3089       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
3090       pushValueAndType(I.getOperand(0), InstID, Vals);
3091     } else {
3092       Code = bitc::FUNC_CODE_INST_LOAD;
3093       if (!pushValueAndType(I.getOperand(0), InstID, Vals)) // ptr
3094         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
3095     }
3096     Vals.push_back(VE.getTypeID(I.getType()));
3097     Vals.push_back(getEncodedAlign(cast<LoadInst>(I).getAlign()));
3098     Vals.push_back(cast<LoadInst>(I).isVolatile());
3099     if (cast<LoadInst>(I).isAtomic()) {
3100       Vals.push_back(getEncodedOrdering(cast<LoadInst>(I).getOrdering()));
3101       Vals.push_back(getEncodedSyncScopeID(cast<LoadInst>(I).getSyncScopeID()));
3102     }
3103     break;
3104   case Instruction::Store:
3105     if (cast<StoreInst>(I).isAtomic())
3106       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
3107     else
3108       Code = bitc::FUNC_CODE_INST_STORE;
3109     pushValueAndType(I.getOperand(1), InstID, Vals); // ptrty + ptr
3110     pushValueAndType(I.getOperand(0), InstID, Vals); // valty + val
3111     Vals.push_back(getEncodedAlign(cast<StoreInst>(I).getAlign()));
3112     Vals.push_back(cast<StoreInst>(I).isVolatile());
3113     if (cast<StoreInst>(I).isAtomic()) {
3114       Vals.push_back(getEncodedOrdering(cast<StoreInst>(I).getOrdering()));
3115       Vals.push_back(
3116           getEncodedSyncScopeID(cast<StoreInst>(I).getSyncScopeID()));
3117     }
3118     break;
3119   case Instruction::AtomicCmpXchg:
3120     Code = bitc::FUNC_CODE_INST_CMPXCHG;
3121     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
3122     pushValueAndType(I.getOperand(1), InstID, Vals); // cmp.
3123     pushValue(I.getOperand(2), InstID, Vals);        // newval.
3124     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
3125     Vals.push_back(
3126         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
3127     Vals.push_back(
3128         getEncodedSyncScopeID(cast<AtomicCmpXchgInst>(I).getSyncScopeID()));
3129     Vals.push_back(
3130         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
3131     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
3132     Vals.push_back(getEncodedAlign(cast<AtomicCmpXchgInst>(I).getAlign()));
3133     break;
3134   case Instruction::AtomicRMW:
3135     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
3136     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
3137     pushValueAndType(I.getOperand(1), InstID, Vals); // valty + val
3138     Vals.push_back(
3139         getEncodedRMWOperation(cast<AtomicRMWInst>(I).getOperation()));
3140     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
3141     Vals.push_back(getEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
3142     Vals.push_back(
3143         getEncodedSyncScopeID(cast<AtomicRMWInst>(I).getSyncScopeID()));
3144     Vals.push_back(getEncodedAlign(cast<AtomicRMWInst>(I).getAlign()));
3145     break;
3146   case Instruction::Fence:
3147     Code = bitc::FUNC_CODE_INST_FENCE;
3148     Vals.push_back(getEncodedOrdering(cast<FenceInst>(I).getOrdering()));
3149     Vals.push_back(getEncodedSyncScopeID(cast<FenceInst>(I).getSyncScopeID()));
3150     break;
3151   case Instruction::Call: {
3152     const CallInst &CI = cast<CallInst>(I);
3153     FunctionType *FTy = CI.getFunctionType();
3154 
3155     if (CI.hasOperandBundles())
3156       writeOperandBundles(CI, InstID);
3157 
3158     Code = bitc::FUNC_CODE_INST_CALL;
3159 
3160     Vals.push_back(VE.getAttributeListID(CI.getAttributes()));
3161 
3162     unsigned Flags = getOptimizationFlags(&I);
3163     Vals.push_back(CI.getCallingConv() << bitc::CALL_CCONV |
3164                    unsigned(CI.isTailCall()) << bitc::CALL_TAIL |
3165                    unsigned(CI.isMustTailCall()) << bitc::CALL_MUSTTAIL |
3166                    1 << bitc::CALL_EXPLICIT_TYPE |
3167                    unsigned(CI.isNoTailCall()) << bitc::CALL_NOTAIL |
3168                    unsigned(Flags != 0) << bitc::CALL_FMF);
3169     if (Flags != 0)
3170       Vals.push_back(Flags);
3171 
3172     Vals.push_back(VE.getTypeID(FTy));
3173     pushValueAndType(CI.getCalledOperand(), InstID, Vals); // Callee
3174 
3175     // Emit value #'s for the fixed parameters.
3176     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
3177       // Check for labels (can happen with asm labels).
3178       if (FTy->getParamType(i)->isLabelTy())
3179         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
3180       else
3181         pushValue(CI.getArgOperand(i), InstID, Vals); // fixed param.
3182     }
3183 
3184     // Emit type/value pairs for varargs params.
3185     if (FTy->isVarArg()) {
3186       for (unsigned i = FTy->getNumParams(), e = CI.arg_size(); i != e; ++i)
3187         pushValueAndType(CI.getArgOperand(i), InstID, Vals); // varargs
3188     }
3189     break;
3190   }
3191   case Instruction::VAArg:
3192     Code = bitc::FUNC_CODE_INST_VAARG;
3193     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
3194     pushValue(I.getOperand(0), InstID, Vals);                   // valist.
3195     Vals.push_back(VE.getTypeID(I.getType())); // restype.
3196     break;
3197   case Instruction::Freeze:
3198     Code = bitc::FUNC_CODE_INST_FREEZE;
3199     pushValueAndType(I.getOperand(0), InstID, Vals);
3200     break;
3201   }
3202 
3203   Stream.EmitRecord(Code, Vals, AbbrevToUse);
3204   Vals.clear();
3205 }
3206 
3207 /// Write a GlobalValue VST to the module. The purpose of this data structure is
3208 /// to allow clients to efficiently find the function body.
3209 void ModuleBitcodeWriter::writeGlobalValueSymbolTable(
3210   DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3211   // Get the offset of the VST we are writing, and backpatch it into
3212   // the VST forward declaration record.
3213   uint64_t VSTOffset = Stream.GetCurrentBitNo();
3214   // The BitcodeStartBit was the stream offset of the identification block.
3215   VSTOffset -= bitcodeStartBit();
3216   assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
3217   // Note that we add 1 here because the offset is relative to one word
3218   // before the start of the identification block, which was historically
3219   // always the start of the regular bitcode header.
3220   Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32 + 1);
3221 
3222   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3223 
3224   auto Abbv = std::make_shared<BitCodeAbbrev>();
3225   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
3226   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
3227   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
3228   unsigned FnEntryAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3229 
3230   for (const Function &F : M) {
3231     uint64_t Record[2];
3232 
3233     if (F.isDeclaration())
3234       continue;
3235 
3236     Record[0] = VE.getValueID(&F);
3237 
3238     // Save the word offset of the function (from the start of the
3239     // actual bitcode written to the stream).
3240     uint64_t BitcodeIndex = FunctionToBitcodeIndex[&F] - bitcodeStartBit();
3241     assert((BitcodeIndex & 31) == 0 && "function block not 32-bit aligned");
3242     // Note that we add 1 here because the offset is relative to one word
3243     // before the start of the identification block, which was historically
3244     // always the start of the regular bitcode header.
3245     Record[1] = BitcodeIndex / 32 + 1;
3246 
3247     Stream.EmitRecord(bitc::VST_CODE_FNENTRY, Record, FnEntryAbbrev);
3248   }
3249 
3250   Stream.ExitBlock();
3251 }
3252 
3253 /// Emit names for arguments, instructions and basic blocks in a function.
3254 void ModuleBitcodeWriter::writeFunctionLevelValueSymbolTable(
3255     const ValueSymbolTable &VST) {
3256   if (VST.empty())
3257     return;
3258 
3259   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3260 
3261   // FIXME: Set up the abbrev, we know how many values there are!
3262   // FIXME: We know if the type names can use 7-bit ascii.
3263   SmallVector<uint64_t, 64> NameVals;
3264 
3265   for (const ValueName &Name : VST) {
3266     // Figure out the encoding to use for the name.
3267     StringEncoding Bits = getStringEncoding(Name.getKey());
3268 
3269     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
3270     NameVals.push_back(VE.getValueID(Name.getValue()));
3271 
3272     // VST_CODE_ENTRY:   [valueid, namechar x N]
3273     // VST_CODE_BBENTRY: [bbid, namechar x N]
3274     unsigned Code;
3275     if (isa<BasicBlock>(Name.getValue())) {
3276       Code = bitc::VST_CODE_BBENTRY;
3277       if (Bits == SE_Char6)
3278         AbbrevToUse = VST_BBENTRY_6_ABBREV;
3279     } else {
3280       Code = bitc::VST_CODE_ENTRY;
3281       if (Bits == SE_Char6)
3282         AbbrevToUse = VST_ENTRY_6_ABBREV;
3283       else if (Bits == SE_Fixed7)
3284         AbbrevToUse = VST_ENTRY_7_ABBREV;
3285     }
3286 
3287     for (const auto P : Name.getKey())
3288       NameVals.push_back((unsigned char)P);
3289 
3290     // Emit the finished record.
3291     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
3292     NameVals.clear();
3293   }
3294 
3295   Stream.ExitBlock();
3296 }
3297 
3298 void ModuleBitcodeWriter::writeUseList(UseListOrder &&Order) {
3299   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
3300   unsigned Code;
3301   if (isa<BasicBlock>(Order.V))
3302     Code = bitc::USELIST_CODE_BB;
3303   else
3304     Code = bitc::USELIST_CODE_DEFAULT;
3305 
3306   SmallVector<uint64_t, 64> Record(Order.Shuffle.begin(), Order.Shuffle.end());
3307   Record.push_back(VE.getValueID(Order.V));
3308   Stream.EmitRecord(Code, Record);
3309 }
3310 
3311 void ModuleBitcodeWriter::writeUseListBlock(const Function *F) {
3312   assert(VE.shouldPreserveUseListOrder() &&
3313          "Expected to be preserving use-list order");
3314 
3315   auto hasMore = [&]() {
3316     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
3317   };
3318   if (!hasMore())
3319     // Nothing to do.
3320     return;
3321 
3322   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
3323   while (hasMore()) {
3324     writeUseList(std::move(VE.UseListOrders.back()));
3325     VE.UseListOrders.pop_back();
3326   }
3327   Stream.ExitBlock();
3328 }
3329 
3330 /// Emit a function body to the module stream.
3331 void ModuleBitcodeWriter::writeFunction(
3332     const Function &F,
3333     DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3334   // Save the bitcode index of the start of this function block for recording
3335   // in the VST.
3336   FunctionToBitcodeIndex[&F] = Stream.GetCurrentBitNo();
3337 
3338   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
3339   VE.incorporateFunction(F);
3340 
3341   SmallVector<unsigned, 64> Vals;
3342 
3343   // Emit the number of basic blocks, so the reader can create them ahead of
3344   // time.
3345   Vals.push_back(VE.getBasicBlocks().size());
3346   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
3347   Vals.clear();
3348 
3349   // If there are function-local constants, emit them now.
3350   unsigned CstStart, CstEnd;
3351   VE.getFunctionConstantRange(CstStart, CstEnd);
3352   writeConstants(CstStart, CstEnd, false);
3353 
3354   // If there is function-local metadata, emit it now.
3355   writeFunctionMetadata(F);
3356 
3357   // Keep a running idea of what the instruction ID is.
3358   unsigned InstID = CstEnd;
3359 
3360   bool NeedsMetadataAttachment = F.hasMetadata();
3361 
3362   DILocation *LastDL = nullptr;
3363   SmallPtrSet<Function *, 4> BlockAddressUsers;
3364 
3365   // Finally, emit all the instructions, in order.
3366   for (const BasicBlock &BB : F) {
3367     for (const Instruction &I : BB) {
3368       writeInstruction(I, InstID, Vals);
3369 
3370       if (!I.getType()->isVoidTy())
3371         ++InstID;
3372 
3373       // If the instruction has metadata, write a metadata attachment later.
3374       NeedsMetadataAttachment |= I.hasMetadataOtherThanDebugLoc();
3375 
3376       // If the instruction has a debug location, emit it.
3377       DILocation *DL = I.getDebugLoc();
3378       if (!DL)
3379         continue;
3380 
3381       if (DL == LastDL) {
3382         // Just repeat the same debug loc as last time.
3383         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
3384         continue;
3385       }
3386 
3387       Vals.push_back(DL->getLine());
3388       Vals.push_back(DL->getColumn());
3389       Vals.push_back(VE.getMetadataOrNullID(DL->getScope()));
3390       Vals.push_back(VE.getMetadataOrNullID(DL->getInlinedAt()));
3391       Vals.push_back(DL->isImplicitCode());
3392       Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
3393       Vals.clear();
3394 
3395       LastDL = DL;
3396     }
3397 
3398     if (BlockAddress *BA = BlockAddress::lookup(&BB)) {
3399       for (User *U : BA->users()) {
3400         if (auto *I = dyn_cast<Instruction>(U)) {
3401           Function *P = I->getParent()->getParent();
3402           if (P != &F)
3403             BlockAddressUsers.insert(P);
3404         }
3405       }
3406     }
3407   }
3408 
3409   if (!BlockAddressUsers.empty()) {
3410     SmallVector<uint64_t, 4> Record;
3411     Record.reserve(BlockAddressUsers.size());
3412     for (Function *F : BlockAddressUsers)
3413       Record.push_back(VE.getValueID(F));
3414     Stream.EmitRecord(bitc::FUNC_CODE_BLOCKADDR_USERS, Record);
3415   }
3416 
3417   // Emit names for all the instructions etc.
3418   if (auto *Symtab = F.getValueSymbolTable())
3419     writeFunctionLevelValueSymbolTable(*Symtab);
3420 
3421   if (NeedsMetadataAttachment)
3422     writeFunctionMetadataAttachment(F);
3423   if (VE.shouldPreserveUseListOrder())
3424     writeUseListBlock(&F);
3425   VE.purgeFunction();
3426   Stream.ExitBlock();
3427 }
3428 
3429 // Emit blockinfo, which defines the standard abbreviations etc.
3430 void ModuleBitcodeWriter::writeBlockInfo() {
3431   // We only want to emit block info records for blocks that have multiple
3432   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
3433   // Other blocks can define their abbrevs inline.
3434   Stream.EnterBlockInfoBlock();
3435 
3436   { // 8-bit fixed-width VST_CODE_ENTRY/VST_CODE_BBENTRY strings.
3437     auto Abbv = std::make_shared<BitCodeAbbrev>();
3438     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
3439     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3440     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3441     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3442     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3443         VST_ENTRY_8_ABBREV)
3444       llvm_unreachable("Unexpected abbrev ordering!");
3445   }
3446 
3447   { // 7-bit fixed width VST_CODE_ENTRY strings.
3448     auto Abbv = std::make_shared<BitCodeAbbrev>();
3449     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3450     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3451     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3452     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3453     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3454         VST_ENTRY_7_ABBREV)
3455       llvm_unreachable("Unexpected abbrev ordering!");
3456   }
3457   { // 6-bit char6 VST_CODE_ENTRY strings.
3458     auto Abbv = std::make_shared<BitCodeAbbrev>();
3459     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3460     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3461     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3462     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3463     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3464         VST_ENTRY_6_ABBREV)
3465       llvm_unreachable("Unexpected abbrev ordering!");
3466   }
3467   { // 6-bit char6 VST_CODE_BBENTRY strings.
3468     auto Abbv = std::make_shared<BitCodeAbbrev>();
3469     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
3470     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3471     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3472     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3473     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3474         VST_BBENTRY_6_ABBREV)
3475       llvm_unreachable("Unexpected abbrev ordering!");
3476   }
3477 
3478   { // SETTYPE abbrev for CONSTANTS_BLOCK.
3479     auto Abbv = std::make_shared<BitCodeAbbrev>();
3480     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
3481     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
3482                               VE.computeBitsRequiredForTypeIndicies()));
3483     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3484         CONSTANTS_SETTYPE_ABBREV)
3485       llvm_unreachable("Unexpected abbrev ordering!");
3486   }
3487 
3488   { // INTEGER abbrev for CONSTANTS_BLOCK.
3489     auto Abbv = std::make_shared<BitCodeAbbrev>();
3490     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
3491     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3492     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3493         CONSTANTS_INTEGER_ABBREV)
3494       llvm_unreachable("Unexpected abbrev ordering!");
3495   }
3496 
3497   { // CE_CAST abbrev for CONSTANTS_BLOCK.
3498     auto Abbv = std::make_shared<BitCodeAbbrev>();
3499     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
3500     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
3501     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
3502                               VE.computeBitsRequiredForTypeIndicies()));
3503     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
3504 
3505     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3506         CONSTANTS_CE_CAST_Abbrev)
3507       llvm_unreachable("Unexpected abbrev ordering!");
3508   }
3509   { // NULL abbrev for CONSTANTS_BLOCK.
3510     auto Abbv = std::make_shared<BitCodeAbbrev>();
3511     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
3512     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3513         CONSTANTS_NULL_Abbrev)
3514       llvm_unreachable("Unexpected abbrev ordering!");
3515   }
3516 
3517   // FIXME: This should only use space for first class types!
3518 
3519   { // INST_LOAD abbrev for FUNCTION_BLOCK.
3520     auto Abbv = std::make_shared<BitCodeAbbrev>();
3521     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
3522     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
3523     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
3524                               VE.computeBitsRequiredForTypeIndicies()));
3525     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
3526     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
3527     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3528         FUNCTION_INST_LOAD_ABBREV)
3529       llvm_unreachable("Unexpected abbrev ordering!");
3530   }
3531   { // INST_UNOP abbrev for FUNCTION_BLOCK.
3532     auto Abbv = std::make_shared<BitCodeAbbrev>();
3533     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3534     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3535     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3536     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3537         FUNCTION_INST_UNOP_ABBREV)
3538       llvm_unreachable("Unexpected abbrev ordering!");
3539   }
3540   { // INST_UNOP_FLAGS abbrev for FUNCTION_BLOCK.
3541     auto Abbv = std::make_shared<BitCodeAbbrev>();
3542     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3543     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3544     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3545     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3546     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3547         FUNCTION_INST_UNOP_FLAGS_ABBREV)
3548       llvm_unreachable("Unexpected abbrev ordering!");
3549   }
3550   { // INST_BINOP abbrev for FUNCTION_BLOCK.
3551     auto Abbv = std::make_shared<BitCodeAbbrev>();
3552     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3553     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3554     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3555     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3556     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3557         FUNCTION_INST_BINOP_ABBREV)
3558       llvm_unreachable("Unexpected abbrev ordering!");
3559   }
3560   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
3561     auto Abbv = std::make_shared<BitCodeAbbrev>();
3562     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3563     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3564     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3565     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3566     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3567     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3568         FUNCTION_INST_BINOP_FLAGS_ABBREV)
3569       llvm_unreachable("Unexpected abbrev ordering!");
3570   }
3571   { // INST_CAST abbrev for FUNCTION_BLOCK.
3572     auto Abbv = std::make_shared<BitCodeAbbrev>();
3573     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
3574     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
3575     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
3576                               VE.computeBitsRequiredForTypeIndicies()));
3577     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
3578     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3579         FUNCTION_INST_CAST_ABBREV)
3580       llvm_unreachable("Unexpected abbrev ordering!");
3581   }
3582 
3583   { // INST_RET abbrev for FUNCTION_BLOCK.
3584     auto Abbv = std::make_shared<BitCodeAbbrev>();
3585     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3586     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3587         FUNCTION_INST_RET_VOID_ABBREV)
3588       llvm_unreachable("Unexpected abbrev ordering!");
3589   }
3590   { // INST_RET abbrev for FUNCTION_BLOCK.
3591     auto Abbv = std::make_shared<BitCodeAbbrev>();
3592     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3593     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
3594     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3595         FUNCTION_INST_RET_VAL_ABBREV)
3596       llvm_unreachable("Unexpected abbrev ordering!");
3597   }
3598   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
3599     auto Abbv = std::make_shared<BitCodeAbbrev>();
3600     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
3601     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3602         FUNCTION_INST_UNREACHABLE_ABBREV)
3603       llvm_unreachable("Unexpected abbrev ordering!");
3604   }
3605   {
3606     auto Abbv = std::make_shared<BitCodeAbbrev>();
3607     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_GEP));
3608     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
3609     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, // dest ty
3610                               Log2_32_Ceil(VE.getTypes().size() + 1)));
3611     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3612     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
3613     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3614         FUNCTION_INST_GEP_ABBREV)
3615       llvm_unreachable("Unexpected abbrev ordering!");
3616   }
3617 
3618   Stream.ExitBlock();
3619 }
3620 
3621 /// Write the module path strings, currently only used when generating
3622 /// a combined index file.
3623 void IndexBitcodeWriter::writeModStrings() {
3624   Stream.EnterSubblock(bitc::MODULE_STRTAB_BLOCK_ID, 3);
3625 
3626   // TODO: See which abbrev sizes we actually need to emit
3627 
3628   // 8-bit fixed-width MST_ENTRY strings.
3629   auto Abbv = std::make_shared<BitCodeAbbrev>();
3630   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3631   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3632   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3633   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3634   unsigned Abbrev8Bit = Stream.EmitAbbrev(std::move(Abbv));
3635 
3636   // 7-bit fixed width MST_ENTRY strings.
3637   Abbv = std::make_shared<BitCodeAbbrev>();
3638   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3639   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3640   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3641   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3642   unsigned Abbrev7Bit = Stream.EmitAbbrev(std::move(Abbv));
3643 
3644   // 6-bit char6 MST_ENTRY strings.
3645   Abbv = std::make_shared<BitCodeAbbrev>();
3646   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3647   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3648   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3649   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3650   unsigned Abbrev6Bit = Stream.EmitAbbrev(std::move(Abbv));
3651 
3652   // Module Hash, 160 bits SHA1. Optionally, emitted after each MST_CODE_ENTRY.
3653   Abbv = std::make_shared<BitCodeAbbrev>();
3654   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_HASH));
3655   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3656   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3657   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3658   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3659   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3660   unsigned AbbrevHash = Stream.EmitAbbrev(std::move(Abbv));
3661 
3662   SmallVector<unsigned, 64> Vals;
3663   forEachModule(
3664       [&](const StringMapEntry<std::pair<uint64_t, ModuleHash>> &MPSE) {
3665         StringRef Key = MPSE.getKey();
3666         const auto &Value = MPSE.getValue();
3667         StringEncoding Bits = getStringEncoding(Key);
3668         unsigned AbbrevToUse = Abbrev8Bit;
3669         if (Bits == SE_Char6)
3670           AbbrevToUse = Abbrev6Bit;
3671         else if (Bits == SE_Fixed7)
3672           AbbrevToUse = Abbrev7Bit;
3673 
3674         Vals.push_back(Value.first);
3675         Vals.append(Key.begin(), Key.end());
3676 
3677         // Emit the finished record.
3678         Stream.EmitRecord(bitc::MST_CODE_ENTRY, Vals, AbbrevToUse);
3679 
3680         // Emit an optional hash for the module now
3681         const auto &Hash = Value.second;
3682         if (llvm::any_of(Hash, [](uint32_t H) { return H; })) {
3683           Vals.assign(Hash.begin(), Hash.end());
3684           // Emit the hash record.
3685           Stream.EmitRecord(bitc::MST_CODE_HASH, Vals, AbbrevHash);
3686         }
3687 
3688         Vals.clear();
3689       });
3690   Stream.ExitBlock();
3691 }
3692 
3693 /// Write the function type metadata related records that need to appear before
3694 /// a function summary entry (whether per-module or combined).
3695 template <typename Fn>
3696 static void writeFunctionTypeMetadataRecords(BitstreamWriter &Stream,
3697                                              FunctionSummary *FS,
3698                                              Fn GetValueID) {
3699   if (!FS->type_tests().empty())
3700     Stream.EmitRecord(bitc::FS_TYPE_TESTS, FS->type_tests());
3701 
3702   SmallVector<uint64_t, 64> Record;
3703 
3704   auto WriteVFuncIdVec = [&](uint64_t Ty,
3705                              ArrayRef<FunctionSummary::VFuncId> VFs) {
3706     if (VFs.empty())
3707       return;
3708     Record.clear();
3709     for (auto &VF : VFs) {
3710       Record.push_back(VF.GUID);
3711       Record.push_back(VF.Offset);
3712     }
3713     Stream.EmitRecord(Ty, Record);
3714   };
3715 
3716   WriteVFuncIdVec(bitc::FS_TYPE_TEST_ASSUME_VCALLS,
3717                   FS->type_test_assume_vcalls());
3718   WriteVFuncIdVec(bitc::FS_TYPE_CHECKED_LOAD_VCALLS,
3719                   FS->type_checked_load_vcalls());
3720 
3721   auto WriteConstVCallVec = [&](uint64_t Ty,
3722                                 ArrayRef<FunctionSummary::ConstVCall> VCs) {
3723     for (auto &VC : VCs) {
3724       Record.clear();
3725       Record.push_back(VC.VFunc.GUID);
3726       Record.push_back(VC.VFunc.Offset);
3727       llvm::append_range(Record, VC.Args);
3728       Stream.EmitRecord(Ty, Record);
3729     }
3730   };
3731 
3732   WriteConstVCallVec(bitc::FS_TYPE_TEST_ASSUME_CONST_VCALL,
3733                      FS->type_test_assume_const_vcalls());
3734   WriteConstVCallVec(bitc::FS_TYPE_CHECKED_LOAD_CONST_VCALL,
3735                      FS->type_checked_load_const_vcalls());
3736 
3737   auto WriteRange = [&](ConstantRange Range) {
3738     Range = Range.sextOrTrunc(FunctionSummary::ParamAccess::RangeWidth);
3739     assert(Range.getLower().getNumWords() == 1);
3740     assert(Range.getUpper().getNumWords() == 1);
3741     emitSignedInt64(Record, *Range.getLower().getRawData());
3742     emitSignedInt64(Record, *Range.getUpper().getRawData());
3743   };
3744 
3745   if (!FS->paramAccesses().empty()) {
3746     Record.clear();
3747     for (auto &Arg : FS->paramAccesses()) {
3748       size_t UndoSize = Record.size();
3749       Record.push_back(Arg.ParamNo);
3750       WriteRange(Arg.Use);
3751       Record.push_back(Arg.Calls.size());
3752       for (auto &Call : Arg.Calls) {
3753         Record.push_back(Call.ParamNo);
3754         Optional<unsigned> ValueID = GetValueID(Call.Callee);
3755         if (!ValueID) {
3756           // If ValueID is unknown we can't drop just this call, we must drop
3757           // entire parameter.
3758           Record.resize(UndoSize);
3759           break;
3760         }
3761         Record.push_back(*ValueID);
3762         WriteRange(Call.Offsets);
3763       }
3764     }
3765     if (!Record.empty())
3766       Stream.EmitRecord(bitc::FS_PARAM_ACCESS, Record);
3767   }
3768 }
3769 
3770 /// Collect type IDs from type tests used by function.
3771 static void
3772 getReferencedTypeIds(FunctionSummary *FS,
3773                      std::set<GlobalValue::GUID> &ReferencedTypeIds) {
3774   if (!FS->type_tests().empty())
3775     for (auto &TT : FS->type_tests())
3776       ReferencedTypeIds.insert(TT);
3777 
3778   auto GetReferencedTypesFromVFuncIdVec =
3779       [&](ArrayRef<FunctionSummary::VFuncId> VFs) {
3780         for (auto &VF : VFs)
3781           ReferencedTypeIds.insert(VF.GUID);
3782       };
3783 
3784   GetReferencedTypesFromVFuncIdVec(FS->type_test_assume_vcalls());
3785   GetReferencedTypesFromVFuncIdVec(FS->type_checked_load_vcalls());
3786 
3787   auto GetReferencedTypesFromConstVCallVec =
3788       [&](ArrayRef<FunctionSummary::ConstVCall> VCs) {
3789         for (auto &VC : VCs)
3790           ReferencedTypeIds.insert(VC.VFunc.GUID);
3791       };
3792 
3793   GetReferencedTypesFromConstVCallVec(FS->type_test_assume_const_vcalls());
3794   GetReferencedTypesFromConstVCallVec(FS->type_checked_load_const_vcalls());
3795 }
3796 
3797 static void writeWholeProgramDevirtResolutionByArg(
3798     SmallVector<uint64_t, 64> &NameVals, const std::vector<uint64_t> &args,
3799     const WholeProgramDevirtResolution::ByArg &ByArg) {
3800   NameVals.push_back(args.size());
3801   llvm::append_range(NameVals, args);
3802 
3803   NameVals.push_back(ByArg.TheKind);
3804   NameVals.push_back(ByArg.Info);
3805   NameVals.push_back(ByArg.Byte);
3806   NameVals.push_back(ByArg.Bit);
3807 }
3808 
3809 static void writeWholeProgramDevirtResolution(
3810     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3811     uint64_t Id, const WholeProgramDevirtResolution &Wpd) {
3812   NameVals.push_back(Id);
3813 
3814   NameVals.push_back(Wpd.TheKind);
3815   NameVals.push_back(StrtabBuilder.add(Wpd.SingleImplName));
3816   NameVals.push_back(Wpd.SingleImplName.size());
3817 
3818   NameVals.push_back(Wpd.ResByArg.size());
3819   for (auto &A : Wpd.ResByArg)
3820     writeWholeProgramDevirtResolutionByArg(NameVals, A.first, A.second);
3821 }
3822 
3823 static void writeTypeIdSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
3824                                      StringTableBuilder &StrtabBuilder,
3825                                      const std::string &Id,
3826                                      const TypeIdSummary &Summary) {
3827   NameVals.push_back(StrtabBuilder.add(Id));
3828   NameVals.push_back(Id.size());
3829 
3830   NameVals.push_back(Summary.TTRes.TheKind);
3831   NameVals.push_back(Summary.TTRes.SizeM1BitWidth);
3832   NameVals.push_back(Summary.TTRes.AlignLog2);
3833   NameVals.push_back(Summary.TTRes.SizeM1);
3834   NameVals.push_back(Summary.TTRes.BitMask);
3835   NameVals.push_back(Summary.TTRes.InlineBits);
3836 
3837   for (auto &W : Summary.WPDRes)
3838     writeWholeProgramDevirtResolution(NameVals, StrtabBuilder, W.first,
3839                                       W.second);
3840 }
3841 
3842 static void writeTypeIdCompatibleVtableSummaryRecord(
3843     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3844     const std::string &Id, const TypeIdCompatibleVtableInfo &Summary,
3845     ValueEnumerator &VE) {
3846   NameVals.push_back(StrtabBuilder.add(Id));
3847   NameVals.push_back(Id.size());
3848 
3849   for (auto &P : Summary) {
3850     NameVals.push_back(P.AddressPointOffset);
3851     NameVals.push_back(VE.getValueID(P.VTableVI.getValue()));
3852   }
3853 }
3854 
3855 // Helper to emit a single function summary record.
3856 void ModuleBitcodeWriterBase::writePerModuleFunctionSummaryRecord(
3857     SmallVector<uint64_t, 64> &NameVals, GlobalValueSummary *Summary,
3858     unsigned ValueID, unsigned FSCallsAbbrev, unsigned FSCallsProfileAbbrev,
3859     const Function &F) {
3860   NameVals.push_back(ValueID);
3861 
3862   FunctionSummary *FS = cast<FunctionSummary>(Summary);
3863 
3864   writeFunctionTypeMetadataRecords(
3865       Stream, FS, [&](const ValueInfo &VI) -> Optional<unsigned> {
3866         return {VE.getValueID(VI.getValue())};
3867       });
3868 
3869   auto SpecialRefCnts = FS->specialRefCounts();
3870   NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
3871   NameVals.push_back(FS->instCount());
3872   NameVals.push_back(getEncodedFFlags(FS->fflags()));
3873   NameVals.push_back(FS->refs().size());
3874   NameVals.push_back(SpecialRefCnts.first);  // rorefcnt
3875   NameVals.push_back(SpecialRefCnts.second); // worefcnt
3876 
3877   for (auto &RI : FS->refs())
3878     NameVals.push_back(VE.getValueID(RI.getValue()));
3879 
3880   bool HasProfileData =
3881       F.hasProfileData() || ForceSummaryEdgesCold != FunctionSummary::FSHT_None;
3882   for (auto &ECI : FS->calls()) {
3883     NameVals.push_back(getValueId(ECI.first));
3884     if (HasProfileData)
3885       NameVals.push_back(static_cast<uint8_t>(ECI.second.Hotness));
3886     else if (WriteRelBFToSummary)
3887       NameVals.push_back(ECI.second.RelBlockFreq);
3888   }
3889 
3890   unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
3891   unsigned Code =
3892       (HasProfileData ? bitc::FS_PERMODULE_PROFILE
3893                       : (WriteRelBFToSummary ? bitc::FS_PERMODULE_RELBF
3894                                              : bitc::FS_PERMODULE));
3895 
3896   // Emit the finished record.
3897   Stream.EmitRecord(Code, NameVals, FSAbbrev);
3898   NameVals.clear();
3899 }
3900 
3901 // Collect the global value references in the given variable's initializer,
3902 // and emit them in a summary record.
3903 void ModuleBitcodeWriterBase::writeModuleLevelReferences(
3904     const GlobalVariable &V, SmallVector<uint64_t, 64> &NameVals,
3905     unsigned FSModRefsAbbrev, unsigned FSModVTableRefsAbbrev) {
3906   auto VI = Index->getValueInfo(V.getGUID());
3907   if (!VI || VI.getSummaryList().empty()) {
3908     // Only declarations should not have a summary (a declaration might however
3909     // have a summary if the def was in module level asm).
3910     assert(V.isDeclaration());
3911     return;
3912   }
3913   auto *Summary = VI.getSummaryList()[0].get();
3914   NameVals.push_back(VE.getValueID(&V));
3915   GlobalVarSummary *VS = cast<GlobalVarSummary>(Summary);
3916   NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
3917   NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
3918 
3919   auto VTableFuncs = VS->vTableFuncs();
3920   if (!VTableFuncs.empty())
3921     NameVals.push_back(VS->refs().size());
3922 
3923   unsigned SizeBeforeRefs = NameVals.size();
3924   for (auto &RI : VS->refs())
3925     NameVals.push_back(VE.getValueID(RI.getValue()));
3926   // Sort the refs for determinism output, the vector returned by FS->refs() has
3927   // been initialized from a DenseSet.
3928   llvm::sort(drop_begin(NameVals, SizeBeforeRefs));
3929 
3930   if (VTableFuncs.empty())
3931     Stream.EmitRecord(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS, NameVals,
3932                       FSModRefsAbbrev);
3933   else {
3934     // VTableFuncs pairs should already be sorted by offset.
3935     for (auto &P : VTableFuncs) {
3936       NameVals.push_back(VE.getValueID(P.FuncVI.getValue()));
3937       NameVals.push_back(P.VTableOffset);
3938     }
3939 
3940     Stream.EmitRecord(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS, NameVals,
3941                       FSModVTableRefsAbbrev);
3942   }
3943   NameVals.clear();
3944 }
3945 
3946 /// Emit the per-module summary section alongside the rest of
3947 /// the module's bitcode.
3948 void ModuleBitcodeWriterBase::writePerModuleGlobalValueSummary() {
3949   // By default we compile with ThinLTO if the module has a summary, but the
3950   // client can request full LTO with a module flag.
3951   bool IsThinLTO = true;
3952   if (auto *MD =
3953           mdconst::extract_or_null<ConstantInt>(M.getModuleFlag("ThinLTO")))
3954     IsThinLTO = MD->getZExtValue();
3955   Stream.EnterSubblock(IsThinLTO ? bitc::GLOBALVAL_SUMMARY_BLOCK_ID
3956                                  : bitc::FULL_LTO_GLOBALVAL_SUMMARY_BLOCK_ID,
3957                        4);
3958 
3959   Stream.EmitRecord(
3960       bitc::FS_VERSION,
3961       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
3962 
3963   // Write the index flags.
3964   uint64_t Flags = 0;
3965   // Bits 1-3 are set only in the combined index, skip them.
3966   if (Index->enableSplitLTOUnit())
3967     Flags |= 0x8;
3968   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Flags});
3969 
3970   if (Index->begin() == Index->end()) {
3971     Stream.ExitBlock();
3972     return;
3973   }
3974 
3975   for (const auto &GVI : valueIds()) {
3976     Stream.EmitRecord(bitc::FS_VALUE_GUID,
3977                       ArrayRef<uint64_t>{GVI.second, GVI.first});
3978   }
3979 
3980   // Abbrev for FS_PERMODULE_PROFILE.
3981   auto Abbv = std::make_shared<BitCodeAbbrev>();
3982   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_PROFILE));
3983   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3984   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3985   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3986   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3987   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3988   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
3989   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
3990   // numrefs x valueid, n x (valueid, hotness)
3991   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3992   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3993   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3994 
3995   // Abbrev for FS_PERMODULE or FS_PERMODULE_RELBF.
3996   Abbv = std::make_shared<BitCodeAbbrev>();
3997   if (WriteRelBFToSummary)
3998     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_RELBF));
3999   else
4000     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE));
4001   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4002   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4003   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4004   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4005   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4006   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4007   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4008   // numrefs x valueid, n x (valueid [, rel_block_freq])
4009   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4010   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4011   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4012 
4013   // Abbrev for FS_PERMODULE_GLOBALVAR_INIT_REFS.
4014   Abbv = std::make_shared<BitCodeAbbrev>();
4015   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS));
4016   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
4017   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
4018   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));  // valueids
4019   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4020   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4021 
4022   // Abbrev for FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS.
4023   Abbv = std::make_shared<BitCodeAbbrev>();
4024   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS));
4025   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
4026   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
4027   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numrefs
4028   // numrefs x valueid, n x (valueid , offset)
4029   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4030   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4031   unsigned FSModVTableRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4032 
4033   // Abbrev for FS_ALIAS.
4034   Abbv = std::make_shared<BitCodeAbbrev>();
4035   Abbv->Add(BitCodeAbbrevOp(bitc::FS_ALIAS));
4036   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4037   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4038   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4039   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4040 
4041   // Abbrev for FS_TYPE_ID_METADATA
4042   Abbv = std::make_shared<BitCodeAbbrev>();
4043   Abbv->Add(BitCodeAbbrevOp(bitc::FS_TYPE_ID_METADATA));
4044   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid strtab index
4045   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid length
4046   // n x (valueid , offset)
4047   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4048   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4049   unsigned TypeIdCompatibleVtableAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4050 
4051   SmallVector<uint64_t, 64> NameVals;
4052   // Iterate over the list of functions instead of the Index to
4053   // ensure the ordering is stable.
4054   for (const Function &F : M) {
4055     // Summary emission does not support anonymous functions, they have to
4056     // renamed using the anonymous function renaming pass.
4057     if (!F.hasName())
4058       report_fatal_error("Unexpected anonymous function when writing summary");
4059 
4060     ValueInfo VI = Index->getValueInfo(F.getGUID());
4061     if (!VI || VI.getSummaryList().empty()) {
4062       // Only declarations should not have a summary (a declaration might
4063       // however have a summary if the def was in module level asm).
4064       assert(F.isDeclaration());
4065       continue;
4066     }
4067     auto *Summary = VI.getSummaryList()[0].get();
4068     writePerModuleFunctionSummaryRecord(NameVals, Summary, VE.getValueID(&F),
4069                                         FSCallsAbbrev, FSCallsProfileAbbrev, F);
4070   }
4071 
4072   // Capture references from GlobalVariable initializers, which are outside
4073   // of a function scope.
4074   for (const GlobalVariable &G : M.globals())
4075     writeModuleLevelReferences(G, NameVals, FSModRefsAbbrev,
4076                                FSModVTableRefsAbbrev);
4077 
4078   for (const GlobalAlias &A : M.aliases()) {
4079     auto *Aliasee = A.getAliaseeObject();
4080     if (!Aliasee->hasName())
4081       // Nameless function don't have an entry in the summary, skip it.
4082       continue;
4083     auto AliasId = VE.getValueID(&A);
4084     auto AliaseeId = VE.getValueID(Aliasee);
4085     NameVals.push_back(AliasId);
4086     auto *Summary = Index->getGlobalValueSummary(A);
4087     AliasSummary *AS = cast<AliasSummary>(Summary);
4088     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
4089     NameVals.push_back(AliaseeId);
4090     Stream.EmitRecord(bitc::FS_ALIAS, NameVals, FSAliasAbbrev);
4091     NameVals.clear();
4092   }
4093 
4094   for (auto &S : Index->typeIdCompatibleVtableMap()) {
4095     writeTypeIdCompatibleVtableSummaryRecord(NameVals, StrtabBuilder, S.first,
4096                                              S.second, VE);
4097     Stream.EmitRecord(bitc::FS_TYPE_ID_METADATA, NameVals,
4098                       TypeIdCompatibleVtableAbbrev);
4099     NameVals.clear();
4100   }
4101 
4102   Stream.EmitRecord(bitc::FS_BLOCK_COUNT,
4103                     ArrayRef<uint64_t>{Index->getBlockCount()});
4104 
4105   Stream.ExitBlock();
4106 }
4107 
4108 /// Emit the combined summary section into the combined index file.
4109 void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
4110   Stream.EnterSubblock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID, 3);
4111   Stream.EmitRecord(
4112       bitc::FS_VERSION,
4113       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
4114 
4115   // Write the index flags.
4116   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Index.getFlags()});
4117 
4118   for (const auto &GVI : valueIds()) {
4119     Stream.EmitRecord(bitc::FS_VALUE_GUID,
4120                       ArrayRef<uint64_t>{GVI.second, GVI.first});
4121   }
4122 
4123   // Abbrev for FS_COMBINED.
4124   auto Abbv = std::make_shared<BitCodeAbbrev>();
4125   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED));
4126   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4127   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4128   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4129   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4130   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4131   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
4132   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4133   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4134   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4135   // numrefs x valueid, n x (valueid)
4136   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4137   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4138   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4139 
4140   // Abbrev for FS_COMBINED_PROFILE.
4141   Abbv = std::make_shared<BitCodeAbbrev>();
4142   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_PROFILE));
4143   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4144   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4145   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4146   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4147   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4148   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
4149   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4150   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4151   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4152   // numrefs x valueid, n x (valueid, hotness)
4153   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4154   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4155   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4156 
4157   // Abbrev for FS_COMBINED_GLOBALVAR_INIT_REFS.
4158   Abbv = std::make_shared<BitCodeAbbrev>();
4159   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS));
4160   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4161   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4162   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4163   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));    // valueids
4164   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4165   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4166 
4167   // Abbrev for FS_COMBINED_ALIAS.
4168   Abbv = std::make_shared<BitCodeAbbrev>();
4169   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_ALIAS));
4170   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4171   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4172   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4173   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4174   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4175 
4176   // The aliases are emitted as a post-pass, and will point to the value
4177   // id of the aliasee. Save them in a vector for post-processing.
4178   SmallVector<AliasSummary *, 64> Aliases;
4179 
4180   // Save the value id for each summary for alias emission.
4181   DenseMap<const GlobalValueSummary *, unsigned> SummaryToValueIdMap;
4182 
4183   SmallVector<uint64_t, 64> NameVals;
4184 
4185   // Set that will be populated during call to writeFunctionTypeMetadataRecords
4186   // with the type ids referenced by this index file.
4187   std::set<GlobalValue::GUID> ReferencedTypeIds;
4188 
4189   // For local linkage, we also emit the original name separately
4190   // immediately after the record.
4191   auto MaybeEmitOriginalName = [&](GlobalValueSummary &S) {
4192     // We don't need to emit the original name if we are writing the index for
4193     // distributed backends (in which case ModuleToSummariesForIndex is
4194     // non-null). The original name is only needed during the thin link, since
4195     // for SamplePGO the indirect call targets for local functions have
4196     // have the original name annotated in profile.
4197     // Continue to emit it when writing out the entire combined index, which is
4198     // used in testing the thin link via llvm-lto.
4199     if (ModuleToSummariesForIndex || !GlobalValue::isLocalLinkage(S.linkage()))
4200       return;
4201     NameVals.push_back(S.getOriginalName());
4202     Stream.EmitRecord(bitc::FS_COMBINED_ORIGINAL_NAME, NameVals);
4203     NameVals.clear();
4204   };
4205 
4206   std::set<GlobalValue::GUID> DefOrUseGUIDs;
4207   forEachSummary([&](GVInfo I, bool IsAliasee) {
4208     GlobalValueSummary *S = I.second;
4209     assert(S);
4210     DefOrUseGUIDs.insert(I.first);
4211     for (const ValueInfo &VI : S->refs())
4212       DefOrUseGUIDs.insert(VI.getGUID());
4213 
4214     auto ValueId = getValueId(I.first);
4215     assert(ValueId);
4216     SummaryToValueIdMap[S] = *ValueId;
4217 
4218     // If this is invoked for an aliasee, we want to record the above
4219     // mapping, but then not emit a summary entry (if the aliasee is
4220     // to be imported, we will invoke this separately with IsAliasee=false).
4221     if (IsAliasee)
4222       return;
4223 
4224     if (auto *AS = dyn_cast<AliasSummary>(S)) {
4225       // Will process aliases as a post-pass because the reader wants all
4226       // global to be loaded first.
4227       Aliases.push_back(AS);
4228       return;
4229     }
4230 
4231     if (auto *VS = dyn_cast<GlobalVarSummary>(S)) {
4232       NameVals.push_back(*ValueId);
4233       NameVals.push_back(Index.getModuleId(VS->modulePath()));
4234       NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
4235       NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
4236       for (auto &RI : VS->refs()) {
4237         auto RefValueId = getValueId(RI.getGUID());
4238         if (!RefValueId)
4239           continue;
4240         NameVals.push_back(*RefValueId);
4241       }
4242 
4243       // Emit the finished record.
4244       Stream.EmitRecord(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS, NameVals,
4245                         FSModRefsAbbrev);
4246       NameVals.clear();
4247       MaybeEmitOriginalName(*S);
4248       return;
4249     }
4250 
4251     auto GetValueId = [&](const ValueInfo &VI) -> Optional<unsigned> {
4252       return getValueId(VI.getGUID());
4253     };
4254 
4255     auto *FS = cast<FunctionSummary>(S);
4256     writeFunctionTypeMetadataRecords(Stream, FS, GetValueId);
4257     getReferencedTypeIds(FS, ReferencedTypeIds);
4258 
4259     NameVals.push_back(*ValueId);
4260     NameVals.push_back(Index.getModuleId(FS->modulePath()));
4261     NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
4262     NameVals.push_back(FS->instCount());
4263     NameVals.push_back(getEncodedFFlags(FS->fflags()));
4264     NameVals.push_back(FS->entryCount());
4265 
4266     // Fill in below
4267     NameVals.push_back(0); // numrefs
4268     NameVals.push_back(0); // rorefcnt
4269     NameVals.push_back(0); // worefcnt
4270 
4271     unsigned Count = 0, RORefCnt = 0, WORefCnt = 0;
4272     for (auto &RI : FS->refs()) {
4273       auto RefValueId = getValueId(RI.getGUID());
4274       if (!RefValueId)
4275         continue;
4276       NameVals.push_back(*RefValueId);
4277       if (RI.isReadOnly())
4278         RORefCnt++;
4279       else if (RI.isWriteOnly())
4280         WORefCnt++;
4281       Count++;
4282     }
4283     NameVals[6] = Count;
4284     NameVals[7] = RORefCnt;
4285     NameVals[8] = WORefCnt;
4286 
4287     bool HasProfileData = false;
4288     for (auto &EI : FS->calls()) {
4289       HasProfileData |=
4290           EI.second.getHotness() != CalleeInfo::HotnessType::Unknown;
4291       if (HasProfileData)
4292         break;
4293     }
4294 
4295     for (auto &EI : FS->calls()) {
4296       // If this GUID doesn't have a value id, it doesn't have a function
4297       // summary and we don't need to record any calls to it.
4298       Optional<unsigned> CallValueId = GetValueId(EI.first);
4299       if (!CallValueId)
4300         continue;
4301       NameVals.push_back(*CallValueId);
4302       if (HasProfileData)
4303         NameVals.push_back(static_cast<uint8_t>(EI.second.Hotness));
4304     }
4305 
4306     unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
4307     unsigned Code =
4308         (HasProfileData ? bitc::FS_COMBINED_PROFILE : bitc::FS_COMBINED);
4309 
4310     // Emit the finished record.
4311     Stream.EmitRecord(Code, NameVals, FSAbbrev);
4312     NameVals.clear();
4313     MaybeEmitOriginalName(*S);
4314   });
4315 
4316   for (auto *AS : Aliases) {
4317     auto AliasValueId = SummaryToValueIdMap[AS];
4318     assert(AliasValueId);
4319     NameVals.push_back(AliasValueId);
4320     NameVals.push_back(Index.getModuleId(AS->modulePath()));
4321     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
4322     auto AliaseeValueId = SummaryToValueIdMap[&AS->getAliasee()];
4323     assert(AliaseeValueId);
4324     NameVals.push_back(AliaseeValueId);
4325 
4326     // Emit the finished record.
4327     Stream.EmitRecord(bitc::FS_COMBINED_ALIAS, NameVals, FSAliasAbbrev);
4328     NameVals.clear();
4329     MaybeEmitOriginalName(*AS);
4330 
4331     if (auto *FS = dyn_cast<FunctionSummary>(&AS->getAliasee()))
4332       getReferencedTypeIds(FS, ReferencedTypeIds);
4333   }
4334 
4335   if (!Index.cfiFunctionDefs().empty()) {
4336     for (auto &S : Index.cfiFunctionDefs()) {
4337       if (DefOrUseGUIDs.count(
4338               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4339         NameVals.push_back(StrtabBuilder.add(S));
4340         NameVals.push_back(S.size());
4341       }
4342     }
4343     if (!NameVals.empty()) {
4344       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DEFS, NameVals);
4345       NameVals.clear();
4346     }
4347   }
4348 
4349   if (!Index.cfiFunctionDecls().empty()) {
4350     for (auto &S : Index.cfiFunctionDecls()) {
4351       if (DefOrUseGUIDs.count(
4352               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4353         NameVals.push_back(StrtabBuilder.add(S));
4354         NameVals.push_back(S.size());
4355       }
4356     }
4357     if (!NameVals.empty()) {
4358       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DECLS, NameVals);
4359       NameVals.clear();
4360     }
4361   }
4362 
4363   // Walk the GUIDs that were referenced, and write the
4364   // corresponding type id records.
4365   for (auto &T : ReferencedTypeIds) {
4366     auto TidIter = Index.typeIds().equal_range(T);
4367     for (auto It = TidIter.first; It != TidIter.second; ++It) {
4368       writeTypeIdSummaryRecord(NameVals, StrtabBuilder, It->second.first,
4369                                It->second.second);
4370       Stream.EmitRecord(bitc::FS_TYPE_ID, NameVals);
4371       NameVals.clear();
4372     }
4373   }
4374 
4375   Stream.EmitRecord(bitc::FS_BLOCK_COUNT,
4376                     ArrayRef<uint64_t>{Index.getBlockCount()});
4377 
4378   Stream.ExitBlock();
4379 }
4380 
4381 /// Create the "IDENTIFICATION_BLOCK_ID" containing a single string with the
4382 /// current llvm version, and a record for the epoch number.
4383 static void writeIdentificationBlock(BitstreamWriter &Stream) {
4384   Stream.EnterSubblock(bitc::IDENTIFICATION_BLOCK_ID, 5);
4385 
4386   // Write the "user readable" string identifying the bitcode producer
4387   auto Abbv = std::make_shared<BitCodeAbbrev>();
4388   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_STRING));
4389   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4390   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
4391   auto StringAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4392   writeStringRecord(Stream, bitc::IDENTIFICATION_CODE_STRING,
4393                     "LLVM" LLVM_VERSION_STRING, StringAbbrev);
4394 
4395   // Write the epoch version
4396   Abbv = std::make_shared<BitCodeAbbrev>();
4397   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_EPOCH));
4398   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
4399   auto EpochAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4400   constexpr std::array<unsigned, 1> Vals = {{bitc::BITCODE_CURRENT_EPOCH}};
4401   Stream.EmitRecord(bitc::IDENTIFICATION_CODE_EPOCH, Vals, EpochAbbrev);
4402   Stream.ExitBlock();
4403 }
4404 
4405 void ModuleBitcodeWriter::writeModuleHash(size_t BlockStartPos) {
4406   // Emit the module's hash.
4407   // MODULE_CODE_HASH: [5*i32]
4408   if (GenerateHash) {
4409     uint32_t Vals[5];
4410     Hasher.update(ArrayRef<uint8_t>((const uint8_t *)&(Buffer)[BlockStartPos],
4411                                     Buffer.size() - BlockStartPos));
4412     std::array<uint8_t, 20> Hash = Hasher.result();
4413     for (int Pos = 0; Pos < 20; Pos += 4) {
4414       Vals[Pos / 4] = support::endian::read32be(Hash.data() + Pos);
4415     }
4416 
4417     // Emit the finished record.
4418     Stream.EmitRecord(bitc::MODULE_CODE_HASH, Vals);
4419 
4420     if (ModHash)
4421       // Save the written hash value.
4422       llvm::copy(Vals, std::begin(*ModHash));
4423   }
4424 }
4425 
4426 void ModuleBitcodeWriter::write() {
4427   writeIdentificationBlock(Stream);
4428 
4429   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4430   size_t BlockStartPos = Buffer.size();
4431 
4432   writeModuleVersion();
4433 
4434   // Emit blockinfo, which defines the standard abbreviations etc.
4435   writeBlockInfo();
4436 
4437   // Emit information describing all of the types in the module.
4438   writeTypeTable();
4439 
4440   // Emit information about attribute groups.
4441   writeAttributeGroupTable();
4442 
4443   // Emit information about parameter attributes.
4444   writeAttributeTable();
4445 
4446   writeComdats();
4447 
4448   // Emit top-level description of module, including target triple, inline asm,
4449   // descriptors for global variables, and function prototype info.
4450   writeModuleInfo();
4451 
4452   // Emit constants.
4453   writeModuleConstants();
4454 
4455   // Emit metadata kind names.
4456   writeModuleMetadataKinds();
4457 
4458   // Emit metadata.
4459   writeModuleMetadata();
4460 
4461   // Emit module-level use-lists.
4462   if (VE.shouldPreserveUseListOrder())
4463     writeUseListBlock(nullptr);
4464 
4465   writeOperandBundleTags();
4466   writeSyncScopeNames();
4467 
4468   // Emit function bodies.
4469   DenseMap<const Function *, uint64_t> FunctionToBitcodeIndex;
4470   for (const Function &F : M)
4471     if (!F.isDeclaration())
4472       writeFunction(F, FunctionToBitcodeIndex);
4473 
4474   // Need to write after the above call to WriteFunction which populates
4475   // the summary information in the index.
4476   if (Index)
4477     writePerModuleGlobalValueSummary();
4478 
4479   writeGlobalValueSymbolTable(FunctionToBitcodeIndex);
4480 
4481   writeModuleHash(BlockStartPos);
4482 
4483   Stream.ExitBlock();
4484 }
4485 
4486 static void writeInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
4487                                uint32_t &Position) {
4488   support::endian::write32le(&Buffer[Position], Value);
4489   Position += 4;
4490 }
4491 
4492 /// If generating a bc file on darwin, we have to emit a
4493 /// header and trailer to make it compatible with the system archiver.  To do
4494 /// this we emit the following header, and then emit a trailer that pads the
4495 /// file out to be a multiple of 16 bytes.
4496 ///
4497 /// struct bc_header {
4498 ///   uint32_t Magic;         // 0x0B17C0DE
4499 ///   uint32_t Version;       // Version, currently always 0.
4500 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
4501 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
4502 ///   uint32_t CPUType;       // CPU specifier.
4503 ///   ... potentially more later ...
4504 /// };
4505 static void emitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
4506                                          const Triple &TT) {
4507   unsigned CPUType = ~0U;
4508 
4509   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
4510   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
4511   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
4512   // specific constants here because they are implicitly part of the Darwin ABI.
4513   enum {
4514     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
4515     DARWIN_CPU_TYPE_X86        = 7,
4516     DARWIN_CPU_TYPE_ARM        = 12,
4517     DARWIN_CPU_TYPE_POWERPC    = 18
4518   };
4519 
4520   Triple::ArchType Arch = TT.getArch();
4521   if (Arch == Triple::x86_64)
4522     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
4523   else if (Arch == Triple::x86)
4524     CPUType = DARWIN_CPU_TYPE_X86;
4525   else if (Arch == Triple::ppc)
4526     CPUType = DARWIN_CPU_TYPE_POWERPC;
4527   else if (Arch == Triple::ppc64)
4528     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
4529   else if (Arch == Triple::arm || Arch == Triple::thumb)
4530     CPUType = DARWIN_CPU_TYPE_ARM;
4531 
4532   // Traditional Bitcode starts after header.
4533   assert(Buffer.size() >= BWH_HeaderSize &&
4534          "Expected header size to be reserved");
4535   unsigned BCOffset = BWH_HeaderSize;
4536   unsigned BCSize = Buffer.size() - BWH_HeaderSize;
4537 
4538   // Write the magic and version.
4539   unsigned Position = 0;
4540   writeInt32ToBuffer(0x0B17C0DE, Buffer, Position);
4541   writeInt32ToBuffer(0, Buffer, Position); // Version.
4542   writeInt32ToBuffer(BCOffset, Buffer, Position);
4543   writeInt32ToBuffer(BCSize, Buffer, Position);
4544   writeInt32ToBuffer(CPUType, Buffer, Position);
4545 
4546   // If the file is not a multiple of 16 bytes, insert dummy padding.
4547   while (Buffer.size() & 15)
4548     Buffer.push_back(0);
4549 }
4550 
4551 /// Helper to write the header common to all bitcode files.
4552 static void writeBitcodeHeader(BitstreamWriter &Stream) {
4553   // Emit the file header.
4554   Stream.Emit((unsigned)'B', 8);
4555   Stream.Emit((unsigned)'C', 8);
4556   Stream.Emit(0x0, 4);
4557   Stream.Emit(0xC, 4);
4558   Stream.Emit(0xE, 4);
4559   Stream.Emit(0xD, 4);
4560 }
4561 
4562 BitcodeWriter::BitcodeWriter(SmallVectorImpl<char> &Buffer, raw_fd_stream *FS)
4563     : Buffer(Buffer), Stream(new BitstreamWriter(Buffer, FS, FlushThreshold)) {
4564   writeBitcodeHeader(*Stream);
4565 }
4566 
4567 BitcodeWriter::~BitcodeWriter() { assert(WroteStrtab); }
4568 
4569 void BitcodeWriter::writeBlob(unsigned Block, unsigned Record, StringRef Blob) {
4570   Stream->EnterSubblock(Block, 3);
4571 
4572   auto Abbv = std::make_shared<BitCodeAbbrev>();
4573   Abbv->Add(BitCodeAbbrevOp(Record));
4574   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
4575   auto AbbrevNo = Stream->EmitAbbrev(std::move(Abbv));
4576 
4577   Stream->EmitRecordWithBlob(AbbrevNo, ArrayRef<uint64_t>{Record}, Blob);
4578 
4579   Stream->ExitBlock();
4580 }
4581 
4582 void BitcodeWriter::writeSymtab() {
4583   assert(!WroteStrtab && !WroteSymtab);
4584 
4585   // If any module has module-level inline asm, we will require a registered asm
4586   // parser for the target so that we can create an accurate symbol table for
4587   // the module.
4588   for (Module *M : Mods) {
4589     if (M->getModuleInlineAsm().empty())
4590       continue;
4591 
4592     std::string Err;
4593     const Triple TT(M->getTargetTriple());
4594     const Target *T = TargetRegistry::lookupTarget(TT.str(), Err);
4595     if (!T || !T->hasMCAsmParser())
4596       return;
4597   }
4598 
4599   WroteSymtab = true;
4600   SmallVector<char, 0> Symtab;
4601   // The irsymtab::build function may be unable to create a symbol table if the
4602   // module is malformed (e.g. it contains an invalid alias). Writing a symbol
4603   // table is not required for correctness, but we still want to be able to
4604   // write malformed modules to bitcode files, so swallow the error.
4605   if (Error E = irsymtab::build(Mods, Symtab, StrtabBuilder, Alloc)) {
4606     consumeError(std::move(E));
4607     return;
4608   }
4609 
4610   writeBlob(bitc::SYMTAB_BLOCK_ID, bitc::SYMTAB_BLOB,
4611             {Symtab.data(), Symtab.size()});
4612 }
4613 
4614 void BitcodeWriter::writeStrtab() {
4615   assert(!WroteStrtab);
4616 
4617   std::vector<char> Strtab;
4618   StrtabBuilder.finalizeInOrder();
4619   Strtab.resize(StrtabBuilder.getSize());
4620   StrtabBuilder.write((uint8_t *)Strtab.data());
4621 
4622   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB,
4623             {Strtab.data(), Strtab.size()});
4624 
4625   WroteStrtab = true;
4626 }
4627 
4628 void BitcodeWriter::copyStrtab(StringRef Strtab) {
4629   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB, Strtab);
4630   WroteStrtab = true;
4631 }
4632 
4633 void BitcodeWriter::writeModule(const Module &M,
4634                                 bool ShouldPreserveUseListOrder,
4635                                 const ModuleSummaryIndex *Index,
4636                                 bool GenerateHash, ModuleHash *ModHash) {
4637   assert(!WroteStrtab);
4638 
4639   // The Mods vector is used by irsymtab::build, which requires non-const
4640   // Modules in case it needs to materialize metadata. But the bitcode writer
4641   // requires that the module is materialized, so we can cast to non-const here,
4642   // after checking that it is in fact materialized.
4643   assert(M.isMaterialized());
4644   Mods.push_back(const_cast<Module *>(&M));
4645 
4646   ModuleBitcodeWriter ModuleWriter(M, Buffer, StrtabBuilder, *Stream,
4647                                    ShouldPreserveUseListOrder, Index,
4648                                    GenerateHash, ModHash);
4649   ModuleWriter.write();
4650 }
4651 
4652 void BitcodeWriter::writeIndex(
4653     const ModuleSummaryIndex *Index,
4654     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4655   IndexBitcodeWriter IndexWriter(*Stream, StrtabBuilder, *Index,
4656                                  ModuleToSummariesForIndex);
4657   IndexWriter.write();
4658 }
4659 
4660 /// Write the specified module to the specified output stream.
4661 void llvm::WriteBitcodeToFile(const Module &M, raw_ostream &Out,
4662                               bool ShouldPreserveUseListOrder,
4663                               const ModuleSummaryIndex *Index,
4664                               bool GenerateHash, ModuleHash *ModHash) {
4665   SmallVector<char, 0> Buffer;
4666   Buffer.reserve(256*1024);
4667 
4668   // If this is darwin or another generic macho target, reserve space for the
4669   // header.
4670   Triple TT(M.getTargetTriple());
4671   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4672     Buffer.insert(Buffer.begin(), BWH_HeaderSize, 0);
4673 
4674   BitcodeWriter Writer(Buffer, dyn_cast<raw_fd_stream>(&Out));
4675   Writer.writeModule(M, ShouldPreserveUseListOrder, Index, GenerateHash,
4676                      ModHash);
4677   Writer.writeSymtab();
4678   Writer.writeStrtab();
4679 
4680   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4681     emitDarwinBCHeaderAndTrailer(Buffer, TT);
4682 
4683   // Write the generated bitstream to "Out".
4684   if (!Buffer.empty())
4685     Out.write((char *)&Buffer.front(), Buffer.size());
4686 }
4687 
4688 void IndexBitcodeWriter::write() {
4689   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4690 
4691   writeModuleVersion();
4692 
4693   // Write the module paths in the combined index.
4694   writeModStrings();
4695 
4696   // Write the summary combined index records.
4697   writeCombinedGlobalValueSummary();
4698 
4699   Stream.ExitBlock();
4700 }
4701 
4702 // Write the specified module summary index to the given raw output stream,
4703 // where it will be written in a new bitcode block. This is used when
4704 // writing the combined index file for ThinLTO. When writing a subset of the
4705 // index for a distributed backend, provide a \p ModuleToSummariesForIndex map.
4706 void llvm::writeIndexToFile(
4707     const ModuleSummaryIndex &Index, raw_ostream &Out,
4708     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4709   SmallVector<char, 0> Buffer;
4710   Buffer.reserve(256 * 1024);
4711 
4712   BitcodeWriter Writer(Buffer);
4713   Writer.writeIndex(&Index, ModuleToSummariesForIndex);
4714   Writer.writeStrtab();
4715 
4716   Out.write((char *)&Buffer.front(), Buffer.size());
4717 }
4718 
4719 namespace {
4720 
4721 /// Class to manage the bitcode writing for a thin link bitcode file.
4722 class ThinLinkBitcodeWriter : public ModuleBitcodeWriterBase {
4723   /// ModHash is for use in ThinLTO incremental build, generated while writing
4724   /// the module bitcode file.
4725   const ModuleHash *ModHash;
4726 
4727 public:
4728   ThinLinkBitcodeWriter(const Module &M, StringTableBuilder &StrtabBuilder,
4729                         BitstreamWriter &Stream,
4730                         const ModuleSummaryIndex &Index,
4731                         const ModuleHash &ModHash)
4732       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
4733                                 /*ShouldPreserveUseListOrder=*/false, &Index),
4734         ModHash(&ModHash) {}
4735 
4736   void write();
4737 
4738 private:
4739   void writeSimplifiedModuleInfo();
4740 };
4741 
4742 } // end anonymous namespace
4743 
4744 // This function writes a simpilified module info for thin link bitcode file.
4745 // It only contains the source file name along with the name(the offset and
4746 // size in strtab) and linkage for global values. For the global value info
4747 // entry, in order to keep linkage at offset 5, there are three zeros used
4748 // as padding.
4749 void ThinLinkBitcodeWriter::writeSimplifiedModuleInfo() {
4750   SmallVector<unsigned, 64> Vals;
4751   // Emit the module's source file name.
4752   {
4753     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
4754     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
4755     if (Bits == SE_Char6)
4756       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
4757     else if (Bits == SE_Fixed7)
4758       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
4759 
4760     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
4761     auto Abbv = std::make_shared<BitCodeAbbrev>();
4762     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
4763     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4764     Abbv->Add(AbbrevOpToUse);
4765     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4766 
4767     for (const auto P : M.getSourceFileName())
4768       Vals.push_back((unsigned char)P);
4769 
4770     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
4771     Vals.clear();
4772   }
4773 
4774   // Emit the global variable information.
4775   for (const GlobalVariable &GV : M.globals()) {
4776     // GLOBALVAR: [strtab offset, strtab size, 0, 0, 0, linkage]
4777     Vals.push_back(StrtabBuilder.add(GV.getName()));
4778     Vals.push_back(GV.getName().size());
4779     Vals.push_back(0);
4780     Vals.push_back(0);
4781     Vals.push_back(0);
4782     Vals.push_back(getEncodedLinkage(GV));
4783 
4784     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals);
4785     Vals.clear();
4786   }
4787 
4788   // Emit the function proto information.
4789   for (const Function &F : M) {
4790     // FUNCTION:  [strtab offset, strtab size, 0, 0, 0, linkage]
4791     Vals.push_back(StrtabBuilder.add(F.getName()));
4792     Vals.push_back(F.getName().size());
4793     Vals.push_back(0);
4794     Vals.push_back(0);
4795     Vals.push_back(0);
4796     Vals.push_back(getEncodedLinkage(F));
4797 
4798     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals);
4799     Vals.clear();
4800   }
4801 
4802   // Emit the alias information.
4803   for (const GlobalAlias &A : M.aliases()) {
4804     // ALIAS: [strtab offset, strtab size, 0, 0, 0, linkage]
4805     Vals.push_back(StrtabBuilder.add(A.getName()));
4806     Vals.push_back(A.getName().size());
4807     Vals.push_back(0);
4808     Vals.push_back(0);
4809     Vals.push_back(0);
4810     Vals.push_back(getEncodedLinkage(A));
4811 
4812     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals);
4813     Vals.clear();
4814   }
4815 
4816   // Emit the ifunc information.
4817   for (const GlobalIFunc &I : M.ifuncs()) {
4818     // IFUNC: [strtab offset, strtab size, 0, 0, 0, linkage]
4819     Vals.push_back(StrtabBuilder.add(I.getName()));
4820     Vals.push_back(I.getName().size());
4821     Vals.push_back(0);
4822     Vals.push_back(0);
4823     Vals.push_back(0);
4824     Vals.push_back(getEncodedLinkage(I));
4825 
4826     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
4827     Vals.clear();
4828   }
4829 }
4830 
4831 void ThinLinkBitcodeWriter::write() {
4832   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4833 
4834   writeModuleVersion();
4835 
4836   writeSimplifiedModuleInfo();
4837 
4838   writePerModuleGlobalValueSummary();
4839 
4840   // Write module hash.
4841   Stream.EmitRecord(bitc::MODULE_CODE_HASH, ArrayRef<uint32_t>(*ModHash));
4842 
4843   Stream.ExitBlock();
4844 }
4845 
4846 void BitcodeWriter::writeThinLinkBitcode(const Module &M,
4847                                          const ModuleSummaryIndex &Index,
4848                                          const ModuleHash &ModHash) {
4849   assert(!WroteStrtab);
4850 
4851   // The Mods vector is used by irsymtab::build, which requires non-const
4852   // Modules in case it needs to materialize metadata. But the bitcode writer
4853   // requires that the module is materialized, so we can cast to non-const here,
4854   // after checking that it is in fact materialized.
4855   assert(M.isMaterialized());
4856   Mods.push_back(const_cast<Module *>(&M));
4857 
4858   ThinLinkBitcodeWriter ThinLinkWriter(M, StrtabBuilder, *Stream, Index,
4859                                        ModHash);
4860   ThinLinkWriter.write();
4861 }
4862 
4863 // Write the specified thin link bitcode file to the given raw output stream,
4864 // where it will be written in a new bitcode block. This is used when
4865 // writing the per-module index file for ThinLTO.
4866 void llvm::writeThinLinkBitcodeToFile(const Module &M, raw_ostream &Out,
4867                                       const ModuleSummaryIndex &Index,
4868                                       const ModuleHash &ModHash) {
4869   SmallVector<char, 0> Buffer;
4870   Buffer.reserve(256 * 1024);
4871 
4872   BitcodeWriter Writer(Buffer);
4873   Writer.writeThinLinkBitcode(M, Index, ModHash);
4874   Writer.writeSymtab();
4875   Writer.writeStrtab();
4876 
4877   Out.write((char *)&Buffer.front(), Buffer.size());
4878 }
4879 
4880 static const char *getSectionNameForBitcode(const Triple &T) {
4881   switch (T.getObjectFormat()) {
4882   case Triple::MachO:
4883     return "__LLVM,__bitcode";
4884   case Triple::COFF:
4885   case Triple::ELF:
4886   case Triple::Wasm:
4887   case Triple::UnknownObjectFormat:
4888     return ".llvmbc";
4889   case Triple::GOFF:
4890     llvm_unreachable("GOFF is not yet implemented");
4891     break;
4892   case Triple::XCOFF:
4893     llvm_unreachable("XCOFF is not yet implemented");
4894     break;
4895   case Triple::DXContainer:
4896     llvm_unreachable("DXContainer is not yet implemented");
4897     break;
4898   }
4899   llvm_unreachable("Unimplemented ObjectFormatType");
4900 }
4901 
4902 static const char *getSectionNameForCommandline(const Triple &T) {
4903   switch (T.getObjectFormat()) {
4904   case Triple::MachO:
4905     return "__LLVM,__cmdline";
4906   case Triple::COFF:
4907   case Triple::ELF:
4908   case Triple::Wasm:
4909   case Triple::UnknownObjectFormat:
4910     return ".llvmcmd";
4911   case Triple::GOFF:
4912     llvm_unreachable("GOFF is not yet implemented");
4913     break;
4914   case Triple::XCOFF:
4915     llvm_unreachable("XCOFF is not yet implemented");
4916     break;
4917   case Triple::DXContainer:
4918     llvm_unreachable("DXC is not yet implemented");
4919     break;
4920   }
4921   llvm_unreachable("Unimplemented ObjectFormatType");
4922 }
4923 
4924 void llvm::embedBitcodeInModule(llvm::Module &M, llvm::MemoryBufferRef Buf,
4925                                 bool EmbedBitcode, bool EmbedCmdline,
4926                                 const std::vector<uint8_t> &CmdArgs) {
4927   // Save llvm.compiler.used and remove it.
4928   SmallVector<Constant *, 2> UsedArray;
4929   SmallVector<GlobalValue *, 4> UsedGlobals;
4930   Type *UsedElementType = Type::getInt8Ty(M.getContext())->getPointerTo(0);
4931   GlobalVariable *Used = collectUsedGlobalVariables(M, UsedGlobals, true);
4932   for (auto *GV : UsedGlobals) {
4933     if (GV->getName() != "llvm.embedded.module" &&
4934         GV->getName() != "llvm.cmdline")
4935       UsedArray.push_back(
4936           ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
4937   }
4938   if (Used)
4939     Used->eraseFromParent();
4940 
4941   // Embed the bitcode for the llvm module.
4942   std::string Data;
4943   ArrayRef<uint8_t> ModuleData;
4944   Triple T(M.getTargetTriple());
4945 
4946   if (EmbedBitcode) {
4947     if (Buf.getBufferSize() == 0 ||
4948         !isBitcode((const unsigned char *)Buf.getBufferStart(),
4949                    (const unsigned char *)Buf.getBufferEnd())) {
4950       // If the input is LLVM Assembly, bitcode is produced by serializing
4951       // the module. Use-lists order need to be preserved in this case.
4952       llvm::raw_string_ostream OS(Data);
4953       llvm::WriteBitcodeToFile(M, OS, /* ShouldPreserveUseListOrder */ true);
4954       ModuleData =
4955           ArrayRef<uint8_t>((const uint8_t *)OS.str().data(), OS.str().size());
4956     } else
4957       // If the input is LLVM bitcode, write the input byte stream directly.
4958       ModuleData = ArrayRef<uint8_t>((const uint8_t *)Buf.getBufferStart(),
4959                                      Buf.getBufferSize());
4960   }
4961   llvm::Constant *ModuleConstant =
4962       llvm::ConstantDataArray::get(M.getContext(), ModuleData);
4963   llvm::GlobalVariable *GV = new llvm::GlobalVariable(
4964       M, ModuleConstant->getType(), true, llvm::GlobalValue::PrivateLinkage,
4965       ModuleConstant);
4966   GV->setSection(getSectionNameForBitcode(T));
4967   // Set alignment to 1 to prevent padding between two contributions from input
4968   // sections after linking.
4969   GV->setAlignment(Align(1));
4970   UsedArray.push_back(
4971       ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
4972   if (llvm::GlobalVariable *Old =
4973           M.getGlobalVariable("llvm.embedded.module", true)) {
4974     assert(Old->hasZeroLiveUses() &&
4975            "llvm.embedded.module can only be used once in llvm.compiler.used");
4976     GV->takeName(Old);
4977     Old->eraseFromParent();
4978   } else {
4979     GV->setName("llvm.embedded.module");
4980   }
4981 
4982   // Skip if only bitcode needs to be embedded.
4983   if (EmbedCmdline) {
4984     // Embed command-line options.
4985     ArrayRef<uint8_t> CmdData(const_cast<uint8_t *>(CmdArgs.data()),
4986                               CmdArgs.size());
4987     llvm::Constant *CmdConstant =
4988         llvm::ConstantDataArray::get(M.getContext(), CmdData);
4989     GV = new llvm::GlobalVariable(M, CmdConstant->getType(), true,
4990                                   llvm::GlobalValue::PrivateLinkage,
4991                                   CmdConstant);
4992     GV->setSection(getSectionNameForCommandline(T));
4993     GV->setAlignment(Align(1));
4994     UsedArray.push_back(
4995         ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
4996     if (llvm::GlobalVariable *Old = M.getGlobalVariable("llvm.cmdline", true)) {
4997       assert(Old->hasZeroLiveUses() &&
4998              "llvm.cmdline can only be used once in llvm.compiler.used");
4999       GV->takeName(Old);
5000       Old->eraseFromParent();
5001     } else {
5002       GV->setName("llvm.cmdline");
5003     }
5004   }
5005 
5006   if (UsedArray.empty())
5007     return;
5008 
5009   // Recreate llvm.compiler.used.
5010   ArrayType *ATy = ArrayType::get(UsedElementType, UsedArray.size());
5011   auto *NewUsed = new GlobalVariable(
5012       M, ATy, false, llvm::GlobalValue::AppendingLinkage,
5013       llvm::ConstantArray::get(ATy, UsedArray), "llvm.compiler.used");
5014   NewUsed->setSection("llvm.metadata");
5015 }
5016