xref: /llvm-project/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp (revision a14920c0027e73fbe9cd971b914a46c0d754ec1a)
1 //===- Bitcode/Writer/BitcodeWriter.cpp - Bitcode Writer ------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // Bitcode writer implementation.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "llvm/Bitcode/BitcodeWriter.h"
14 #include "ValueEnumerator.h"
15 #include "llvm/ADT/APFloat.h"
16 #include "llvm/ADT/APInt.h"
17 #include "llvm/ADT/ArrayRef.h"
18 #include "llvm/ADT/DenseMap.h"
19 #include "llvm/ADT/None.h"
20 #include "llvm/ADT/Optional.h"
21 #include "llvm/ADT/STLExtras.h"
22 #include "llvm/ADT/SmallString.h"
23 #include "llvm/ADT/SmallVector.h"
24 #include "llvm/ADT/StringMap.h"
25 #include "llvm/ADT/StringRef.h"
26 #include "llvm/ADT/Triple.h"
27 #include "llvm/Bitcode/BitcodeCommon.h"
28 #include "llvm/Bitcode/BitcodeReader.h"
29 #include "llvm/Bitcode/LLVMBitCodes.h"
30 #include "llvm/Bitstream/BitCodes.h"
31 #include "llvm/Bitstream/BitstreamWriter.h"
32 #include "llvm/Config/llvm-config.h"
33 #include "llvm/IR/Attributes.h"
34 #include "llvm/IR/BasicBlock.h"
35 #include "llvm/IR/Comdat.h"
36 #include "llvm/IR/Constant.h"
37 #include "llvm/IR/Constants.h"
38 #include "llvm/IR/DebugInfoMetadata.h"
39 #include "llvm/IR/DebugLoc.h"
40 #include "llvm/IR/DerivedTypes.h"
41 #include "llvm/IR/Function.h"
42 #include "llvm/IR/GlobalAlias.h"
43 #include "llvm/IR/GlobalIFunc.h"
44 #include "llvm/IR/GlobalObject.h"
45 #include "llvm/IR/GlobalValue.h"
46 #include "llvm/IR/GlobalVariable.h"
47 #include "llvm/IR/InlineAsm.h"
48 #include "llvm/IR/InstrTypes.h"
49 #include "llvm/IR/Instruction.h"
50 #include "llvm/IR/Instructions.h"
51 #include "llvm/IR/LLVMContext.h"
52 #include "llvm/IR/Metadata.h"
53 #include "llvm/IR/Module.h"
54 #include "llvm/IR/ModuleSummaryIndex.h"
55 #include "llvm/IR/Operator.h"
56 #include "llvm/IR/Type.h"
57 #include "llvm/IR/UseListOrder.h"
58 #include "llvm/IR/Value.h"
59 #include "llvm/IR/ValueSymbolTable.h"
60 #include "llvm/MC/StringTableBuilder.h"
61 #include "llvm/Object/IRSymtab.h"
62 #include "llvm/Support/AtomicOrdering.h"
63 #include "llvm/Support/Casting.h"
64 #include "llvm/Support/CommandLine.h"
65 #include "llvm/Support/Endian.h"
66 #include "llvm/Support/Error.h"
67 #include "llvm/Support/ErrorHandling.h"
68 #include "llvm/Support/MathExtras.h"
69 #include "llvm/Support/SHA1.h"
70 #include "llvm/Support/TargetRegistry.h"
71 #include "llvm/Support/raw_ostream.h"
72 #include <algorithm>
73 #include <cassert>
74 #include <cstddef>
75 #include <cstdint>
76 #include <iterator>
77 #include <map>
78 #include <memory>
79 #include <string>
80 #include <utility>
81 #include <vector>
82 
83 using namespace llvm;
84 
85 static cl::opt<unsigned>
86     IndexThreshold("bitcode-mdindex-threshold", cl::Hidden, cl::init(25),
87                    cl::desc("Number of metadatas above which we emit an index "
88                             "to enable lazy-loading"));
89 static cl::opt<uint32_t> FlushThreshold(
90     "bitcode-flush-threshold", cl::Hidden, cl::init(512),
91     cl::desc("The threshold (unit M) for flushing LLVM bitcode."));
92 
93 static cl::opt<bool> WriteRelBFToSummary(
94     "write-relbf-to-summary", cl::Hidden, cl::init(false),
95     cl::desc("Write relative block frequency to function summary "));
96 
97 extern FunctionSummary::ForceSummaryHotnessType ForceSummaryEdgesCold;
98 
99 namespace {
100 
101 /// These are manifest constants used by the bitcode writer. They do not need to
102 /// be kept in sync with the reader, but need to be consistent within this file.
103 enum {
104   // VALUE_SYMTAB_BLOCK abbrev id's.
105   VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
106   VST_ENTRY_7_ABBREV,
107   VST_ENTRY_6_ABBREV,
108   VST_BBENTRY_6_ABBREV,
109 
110   // CONSTANTS_BLOCK abbrev id's.
111   CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
112   CONSTANTS_INTEGER_ABBREV,
113   CONSTANTS_CE_CAST_Abbrev,
114   CONSTANTS_NULL_Abbrev,
115 
116   // FUNCTION_BLOCK abbrev id's.
117   FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
118   FUNCTION_INST_UNOP_ABBREV,
119   FUNCTION_INST_UNOP_FLAGS_ABBREV,
120   FUNCTION_INST_BINOP_ABBREV,
121   FUNCTION_INST_BINOP_FLAGS_ABBREV,
122   FUNCTION_INST_CAST_ABBREV,
123   FUNCTION_INST_RET_VOID_ABBREV,
124   FUNCTION_INST_RET_VAL_ABBREV,
125   FUNCTION_INST_UNREACHABLE_ABBREV,
126   FUNCTION_INST_GEP_ABBREV,
127 };
128 
129 /// Abstract class to manage the bitcode writing, subclassed for each bitcode
130 /// file type.
131 class BitcodeWriterBase {
132 protected:
133   /// The stream created and owned by the client.
134   BitstreamWriter &Stream;
135 
136   StringTableBuilder &StrtabBuilder;
137 
138 public:
139   /// Constructs a BitcodeWriterBase object that writes to the provided
140   /// \p Stream.
141   BitcodeWriterBase(BitstreamWriter &Stream, StringTableBuilder &StrtabBuilder)
142       : Stream(Stream), StrtabBuilder(StrtabBuilder) {}
143 
144 protected:
145   void writeModuleVersion();
146 };
147 
148 void BitcodeWriterBase::writeModuleVersion() {
149   // VERSION: [version#]
150   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, ArrayRef<uint64_t>{2});
151 }
152 
153 /// Base class to manage the module bitcode writing, currently subclassed for
154 /// ModuleBitcodeWriter and ThinLinkBitcodeWriter.
155 class ModuleBitcodeWriterBase : public BitcodeWriterBase {
156 protected:
157   /// The Module to write to bitcode.
158   const Module &M;
159 
160   /// Enumerates ids for all values in the module.
161   ValueEnumerator VE;
162 
163   /// Optional per-module index to write for ThinLTO.
164   const ModuleSummaryIndex *Index;
165 
166   /// Map that holds the correspondence between GUIDs in the summary index,
167   /// that came from indirect call profiles, and a value id generated by this
168   /// class to use in the VST and summary block records.
169   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
170 
171   /// Tracks the last value id recorded in the GUIDToValueMap.
172   unsigned GlobalValueId;
173 
174   /// Saves the offset of the VSTOffset record that must eventually be
175   /// backpatched with the offset of the actual VST.
176   uint64_t VSTOffsetPlaceholder = 0;
177 
178 public:
179   /// Constructs a ModuleBitcodeWriterBase object for the given Module,
180   /// writing to the provided \p Buffer.
181   ModuleBitcodeWriterBase(const Module &M, StringTableBuilder &StrtabBuilder,
182                           BitstreamWriter &Stream,
183                           bool ShouldPreserveUseListOrder,
184                           const ModuleSummaryIndex *Index)
185       : BitcodeWriterBase(Stream, StrtabBuilder), M(M),
186         VE(M, ShouldPreserveUseListOrder), Index(Index) {
187     // Assign ValueIds to any callee values in the index that came from
188     // indirect call profiles and were recorded as a GUID not a Value*
189     // (which would have been assigned an ID by the ValueEnumerator).
190     // The starting ValueId is just after the number of values in the
191     // ValueEnumerator, so that they can be emitted in the VST.
192     GlobalValueId = VE.getValues().size();
193     if (!Index)
194       return;
195     for (const auto &GUIDSummaryLists : *Index)
196       // Examine all summaries for this GUID.
197       for (auto &Summary : GUIDSummaryLists.second.SummaryList)
198         if (auto FS = dyn_cast<FunctionSummary>(Summary.get()))
199           // For each call in the function summary, see if the call
200           // is to a GUID (which means it is for an indirect call,
201           // otherwise we would have a Value for it). If so, synthesize
202           // a value id.
203           for (auto &CallEdge : FS->calls())
204             if (!CallEdge.first.haveGVs() || !CallEdge.first.getValue())
205               assignValueId(CallEdge.first.getGUID());
206   }
207 
208 protected:
209   void writePerModuleGlobalValueSummary();
210 
211 private:
212   void writePerModuleFunctionSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
213                                            GlobalValueSummary *Summary,
214                                            unsigned ValueID,
215                                            unsigned FSCallsAbbrev,
216                                            unsigned FSCallsProfileAbbrev,
217                                            const Function &F);
218   void writeModuleLevelReferences(const GlobalVariable &V,
219                                   SmallVector<uint64_t, 64> &NameVals,
220                                   unsigned FSModRefsAbbrev,
221                                   unsigned FSModVTableRefsAbbrev);
222 
223   void assignValueId(GlobalValue::GUID ValGUID) {
224     GUIDToValueIdMap[ValGUID] = ++GlobalValueId;
225   }
226 
227   unsigned getValueId(GlobalValue::GUID ValGUID) {
228     const auto &VMI = GUIDToValueIdMap.find(ValGUID);
229     // Expect that any GUID value had a value Id assigned by an
230     // earlier call to assignValueId.
231     assert(VMI != GUIDToValueIdMap.end() &&
232            "GUID does not have assigned value Id");
233     return VMI->second;
234   }
235 
236   // Helper to get the valueId for the type of value recorded in VI.
237   unsigned getValueId(ValueInfo VI) {
238     if (!VI.haveGVs() || !VI.getValue())
239       return getValueId(VI.getGUID());
240     return VE.getValueID(VI.getValue());
241   }
242 
243   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
244 };
245 
246 /// Class to manage the bitcode writing for a module.
247 class ModuleBitcodeWriter : public ModuleBitcodeWriterBase {
248   /// Pointer to the buffer allocated by caller for bitcode writing.
249   const SmallVectorImpl<char> &Buffer;
250 
251   /// True if a module hash record should be written.
252   bool GenerateHash;
253 
254   /// If non-null, when GenerateHash is true, the resulting hash is written
255   /// into ModHash.
256   ModuleHash *ModHash;
257 
258   SHA1 Hasher;
259 
260   /// The start bit of the identification block.
261   uint64_t BitcodeStartBit;
262 
263 public:
264   /// Constructs a ModuleBitcodeWriter object for the given Module,
265   /// writing to the provided \p Buffer.
266   ModuleBitcodeWriter(const Module &M, SmallVectorImpl<char> &Buffer,
267                       StringTableBuilder &StrtabBuilder,
268                       BitstreamWriter &Stream, bool ShouldPreserveUseListOrder,
269                       const ModuleSummaryIndex *Index, bool GenerateHash,
270                       ModuleHash *ModHash = nullptr)
271       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
272                                 ShouldPreserveUseListOrder, Index),
273         Buffer(Buffer), GenerateHash(GenerateHash), ModHash(ModHash),
274         BitcodeStartBit(Stream.GetCurrentBitNo()) {}
275 
276   /// Emit the current module to the bitstream.
277   void write();
278 
279 private:
280   uint64_t bitcodeStartBit() { return BitcodeStartBit; }
281 
282   size_t addToStrtab(StringRef Str);
283 
284   void writeAttributeGroupTable();
285   void writeAttributeTable();
286   void writeTypeTable();
287   void writeComdats();
288   void writeValueSymbolTableForwardDecl();
289   void writeModuleInfo();
290   void writeValueAsMetadata(const ValueAsMetadata *MD,
291                             SmallVectorImpl<uint64_t> &Record);
292   void writeMDTuple(const MDTuple *N, SmallVectorImpl<uint64_t> &Record,
293                     unsigned Abbrev);
294   unsigned createDILocationAbbrev();
295   void writeDILocation(const DILocation *N, SmallVectorImpl<uint64_t> &Record,
296                        unsigned &Abbrev);
297   unsigned createGenericDINodeAbbrev();
298   void writeGenericDINode(const GenericDINode *N,
299                           SmallVectorImpl<uint64_t> &Record, unsigned &Abbrev);
300   void writeDISubrange(const DISubrange *N, SmallVectorImpl<uint64_t> &Record,
301                        unsigned Abbrev);
302   void writeDIGenericSubrange(const DIGenericSubrange *N,
303                               SmallVectorImpl<uint64_t> &Record,
304                               unsigned Abbrev);
305   void writeDIEnumerator(const DIEnumerator *N,
306                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
307   void writeDIBasicType(const DIBasicType *N, SmallVectorImpl<uint64_t> &Record,
308                         unsigned Abbrev);
309   void writeDIStringType(const DIStringType *N,
310                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
311   void writeDIDerivedType(const DIDerivedType *N,
312                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
313   void writeDICompositeType(const DICompositeType *N,
314                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
315   void writeDISubroutineType(const DISubroutineType *N,
316                              SmallVectorImpl<uint64_t> &Record,
317                              unsigned Abbrev);
318   void writeDIFile(const DIFile *N, SmallVectorImpl<uint64_t> &Record,
319                    unsigned Abbrev);
320   void writeDICompileUnit(const DICompileUnit *N,
321                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
322   void writeDISubprogram(const DISubprogram *N,
323                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
324   void writeDILexicalBlock(const DILexicalBlock *N,
325                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
326   void writeDILexicalBlockFile(const DILexicalBlockFile *N,
327                                SmallVectorImpl<uint64_t> &Record,
328                                unsigned Abbrev);
329   void writeDICommonBlock(const DICommonBlock *N,
330                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
331   void writeDINamespace(const DINamespace *N, SmallVectorImpl<uint64_t> &Record,
332                         unsigned Abbrev);
333   void writeDIMacro(const DIMacro *N, SmallVectorImpl<uint64_t> &Record,
334                     unsigned Abbrev);
335   void writeDIMacroFile(const DIMacroFile *N, SmallVectorImpl<uint64_t> &Record,
336                         unsigned Abbrev);
337   void writeDIArgList(const DIArgList *N, SmallVectorImpl<uint64_t> &Record,
338                       unsigned Abbrev);
339   void writeDIModule(const DIModule *N, SmallVectorImpl<uint64_t> &Record,
340                      unsigned Abbrev);
341   void writeDITemplateTypeParameter(const DITemplateTypeParameter *N,
342                                     SmallVectorImpl<uint64_t> &Record,
343                                     unsigned Abbrev);
344   void writeDITemplateValueParameter(const DITemplateValueParameter *N,
345                                      SmallVectorImpl<uint64_t> &Record,
346                                      unsigned Abbrev);
347   void writeDIGlobalVariable(const DIGlobalVariable *N,
348                              SmallVectorImpl<uint64_t> &Record,
349                              unsigned Abbrev);
350   void writeDILocalVariable(const DILocalVariable *N,
351                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
352   void writeDILabel(const DILabel *N,
353                     SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
354   void writeDIExpression(const DIExpression *N,
355                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
356   void writeDIGlobalVariableExpression(const DIGlobalVariableExpression *N,
357                                        SmallVectorImpl<uint64_t> &Record,
358                                        unsigned Abbrev);
359   void writeDIObjCProperty(const DIObjCProperty *N,
360                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
361   void writeDIImportedEntity(const DIImportedEntity *N,
362                              SmallVectorImpl<uint64_t> &Record,
363                              unsigned Abbrev);
364   unsigned createNamedMetadataAbbrev();
365   void writeNamedMetadata(SmallVectorImpl<uint64_t> &Record);
366   unsigned createMetadataStringsAbbrev();
367   void writeMetadataStrings(ArrayRef<const Metadata *> Strings,
368                             SmallVectorImpl<uint64_t> &Record);
369   void writeMetadataRecords(ArrayRef<const Metadata *> MDs,
370                             SmallVectorImpl<uint64_t> &Record,
371                             std::vector<unsigned> *MDAbbrevs = nullptr,
372                             std::vector<uint64_t> *IndexPos = nullptr);
373   void writeModuleMetadata();
374   void writeFunctionMetadata(const Function &F);
375   void writeFunctionMetadataAttachment(const Function &F);
376   void writeGlobalVariableMetadataAttachment(const GlobalVariable &GV);
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 (unsigned i = 0, e = Str.size(); i != e; ++i) {
601     if (AbbrevToUse && !BitCodeAbbrevOp::isChar6(Str[i]))
602       AbbrevToUse = 0;
603     Vals.push_back(Str[i]);
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::AllocSize:
615     return bitc::ATTR_KIND_ALLOC_SIZE;
616   case Attribute::AlwaysInline:
617     return bitc::ATTR_KIND_ALWAYS_INLINE;
618   case Attribute::ArgMemOnly:
619     return bitc::ATTR_KIND_ARGMEMONLY;
620   case Attribute::Builtin:
621     return bitc::ATTR_KIND_BUILTIN;
622   case Attribute::ByVal:
623     return bitc::ATTR_KIND_BY_VAL;
624   case Attribute::Convergent:
625     return bitc::ATTR_KIND_CONVERGENT;
626   case Attribute::InAlloca:
627     return bitc::ATTR_KIND_IN_ALLOCA;
628   case Attribute::Cold:
629     return bitc::ATTR_KIND_COLD;
630   case Attribute::Hot:
631     return bitc::ATTR_KIND_HOT;
632   case Attribute::ElementType:
633     return bitc::ATTR_KIND_ELEMENTTYPE;
634   case Attribute::InaccessibleMemOnly:
635     return bitc::ATTR_KIND_INACCESSIBLEMEM_ONLY;
636   case Attribute::InaccessibleMemOrArgMemOnly:
637     return bitc::ATTR_KIND_INACCESSIBLEMEM_OR_ARGMEMONLY;
638   case Attribute::InlineHint:
639     return bitc::ATTR_KIND_INLINE_HINT;
640   case Attribute::InReg:
641     return bitc::ATTR_KIND_IN_REG;
642   case Attribute::JumpTable:
643     return bitc::ATTR_KIND_JUMP_TABLE;
644   case Attribute::MinSize:
645     return bitc::ATTR_KIND_MIN_SIZE;
646   case Attribute::Naked:
647     return bitc::ATTR_KIND_NAKED;
648   case Attribute::Nest:
649     return bitc::ATTR_KIND_NEST;
650   case Attribute::NoAlias:
651     return bitc::ATTR_KIND_NO_ALIAS;
652   case Attribute::NoBuiltin:
653     return bitc::ATTR_KIND_NO_BUILTIN;
654   case Attribute::NoCallback:
655     return bitc::ATTR_KIND_NO_CALLBACK;
656   case Attribute::NoCapture:
657     return bitc::ATTR_KIND_NO_CAPTURE;
658   case Attribute::NoDuplicate:
659     return bitc::ATTR_KIND_NO_DUPLICATE;
660   case Attribute::NoFree:
661     return bitc::ATTR_KIND_NOFREE;
662   case Attribute::NoImplicitFloat:
663     return bitc::ATTR_KIND_NO_IMPLICIT_FLOAT;
664   case Attribute::NoInline:
665     return bitc::ATTR_KIND_NO_INLINE;
666   case Attribute::NoRecurse:
667     return bitc::ATTR_KIND_NO_RECURSE;
668   case Attribute::NoMerge:
669     return bitc::ATTR_KIND_NO_MERGE;
670   case Attribute::NonLazyBind:
671     return bitc::ATTR_KIND_NON_LAZY_BIND;
672   case Attribute::NonNull:
673     return bitc::ATTR_KIND_NON_NULL;
674   case Attribute::Dereferenceable:
675     return bitc::ATTR_KIND_DEREFERENCEABLE;
676   case Attribute::DereferenceableOrNull:
677     return bitc::ATTR_KIND_DEREFERENCEABLE_OR_NULL;
678   case Attribute::NoRedZone:
679     return bitc::ATTR_KIND_NO_RED_ZONE;
680   case Attribute::NoReturn:
681     return bitc::ATTR_KIND_NO_RETURN;
682   case Attribute::NoSync:
683     return bitc::ATTR_KIND_NOSYNC;
684   case Attribute::NoCfCheck:
685     return bitc::ATTR_KIND_NOCF_CHECK;
686   case Attribute::NoProfile:
687     return bitc::ATTR_KIND_NO_PROFILE;
688   case Attribute::NoUnwind:
689     return bitc::ATTR_KIND_NO_UNWIND;
690   case Attribute::NoSanitizeCoverage:
691     return bitc::ATTR_KIND_NO_SANITIZE_COVERAGE;
692   case Attribute::NullPointerIsValid:
693     return bitc::ATTR_KIND_NULL_POINTER_IS_VALID;
694   case Attribute::OptForFuzzing:
695     return bitc::ATTR_KIND_OPT_FOR_FUZZING;
696   case Attribute::OptimizeForSize:
697     return bitc::ATTR_KIND_OPTIMIZE_FOR_SIZE;
698   case Attribute::OptimizeNone:
699     return bitc::ATTR_KIND_OPTIMIZE_NONE;
700   case Attribute::ReadNone:
701     return bitc::ATTR_KIND_READ_NONE;
702   case Attribute::ReadOnly:
703     return bitc::ATTR_KIND_READ_ONLY;
704   case Attribute::Returned:
705     return bitc::ATTR_KIND_RETURNED;
706   case Attribute::ReturnsTwice:
707     return bitc::ATTR_KIND_RETURNS_TWICE;
708   case Attribute::SExt:
709     return bitc::ATTR_KIND_S_EXT;
710   case Attribute::Speculatable:
711     return bitc::ATTR_KIND_SPECULATABLE;
712   case Attribute::StackAlignment:
713     return bitc::ATTR_KIND_STACK_ALIGNMENT;
714   case Attribute::StackProtect:
715     return bitc::ATTR_KIND_STACK_PROTECT;
716   case Attribute::StackProtectReq:
717     return bitc::ATTR_KIND_STACK_PROTECT_REQ;
718   case Attribute::StackProtectStrong:
719     return bitc::ATTR_KIND_STACK_PROTECT_STRONG;
720   case Attribute::SafeStack:
721     return bitc::ATTR_KIND_SAFESTACK;
722   case Attribute::ShadowCallStack:
723     return bitc::ATTR_KIND_SHADOWCALLSTACK;
724   case Attribute::StrictFP:
725     return bitc::ATTR_KIND_STRICT_FP;
726   case Attribute::StructRet:
727     return bitc::ATTR_KIND_STRUCT_RET;
728   case Attribute::SanitizeAddress:
729     return bitc::ATTR_KIND_SANITIZE_ADDRESS;
730   case Attribute::SanitizeHWAddress:
731     return bitc::ATTR_KIND_SANITIZE_HWADDRESS;
732   case Attribute::SanitizeThread:
733     return bitc::ATTR_KIND_SANITIZE_THREAD;
734   case Attribute::SanitizeMemory:
735     return bitc::ATTR_KIND_SANITIZE_MEMORY;
736   case Attribute::SpeculativeLoadHardening:
737     return bitc::ATTR_KIND_SPECULATIVE_LOAD_HARDENING;
738   case Attribute::SwiftError:
739     return bitc::ATTR_KIND_SWIFT_ERROR;
740   case Attribute::SwiftSelf:
741     return bitc::ATTR_KIND_SWIFT_SELF;
742   case Attribute::SwiftAsync:
743     return bitc::ATTR_KIND_SWIFT_ASYNC;
744   case Attribute::UWTable:
745     return bitc::ATTR_KIND_UW_TABLE;
746   case Attribute::VScaleRange:
747     return bitc::ATTR_KIND_VSCALE_RANGE;
748   case Attribute::WillReturn:
749     return bitc::ATTR_KIND_WILLRETURN;
750   case Attribute::WriteOnly:
751     return bitc::ATTR_KIND_WRITEONLY;
752   case Attribute::ZExt:
753     return bitc::ATTR_KIND_Z_EXT;
754   case Attribute::ImmArg:
755     return bitc::ATTR_KIND_IMMARG;
756   case Attribute::SanitizeMemTag:
757     return bitc::ATTR_KIND_SANITIZE_MEMTAG;
758   case Attribute::Preallocated:
759     return bitc::ATTR_KIND_PREALLOCATED;
760   case Attribute::NoUndef:
761     return bitc::ATTR_KIND_NOUNDEF;
762   case Attribute::ByRef:
763     return bitc::ATTR_KIND_BYREF;
764   case Attribute::MustProgress:
765     return bitc::ATTR_KIND_MUSTPROGRESS;
766   case Attribute::EndAttrKinds:
767     llvm_unreachable("Can not encode end-attribute kinds marker.");
768   case Attribute::None:
769     llvm_unreachable("Can not encode none-attribute.");
770   case Attribute::EmptyKey:
771   case Attribute::TombstoneKey:
772     llvm_unreachable("Trying to encode EmptyKey/TombstoneKey");
773   }
774 
775   llvm_unreachable("Trying to encode unknown attribute");
776 }
777 
778 void ModuleBitcodeWriter::writeAttributeGroupTable() {
779   const std::vector<ValueEnumerator::IndexAndAttrSet> &AttrGrps =
780       VE.getAttributeGroups();
781   if (AttrGrps.empty()) return;
782 
783   Stream.EnterSubblock(bitc::PARAMATTR_GROUP_BLOCK_ID, 3);
784 
785   SmallVector<uint64_t, 64> Record;
786   for (ValueEnumerator::IndexAndAttrSet Pair : AttrGrps) {
787     unsigned AttrListIndex = Pair.first;
788     AttributeSet AS = Pair.second;
789     Record.push_back(VE.getAttributeGroupID(Pair));
790     Record.push_back(AttrListIndex);
791 
792     for (Attribute Attr : AS) {
793       if (Attr.isEnumAttribute()) {
794         Record.push_back(0);
795         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
796       } else if (Attr.isIntAttribute()) {
797         Record.push_back(1);
798         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
799         Record.push_back(Attr.getValueAsInt());
800       } else if (Attr.isStringAttribute()) {
801         StringRef Kind = Attr.getKindAsString();
802         StringRef Val = Attr.getValueAsString();
803 
804         Record.push_back(Val.empty() ? 3 : 4);
805         Record.append(Kind.begin(), Kind.end());
806         Record.push_back(0);
807         if (!Val.empty()) {
808           Record.append(Val.begin(), Val.end());
809           Record.push_back(0);
810         }
811       } else {
812         assert(Attr.isTypeAttribute());
813         Type *Ty = Attr.getValueAsType();
814         Record.push_back(Ty ? 6 : 5);
815         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
816         if (Ty)
817           Record.push_back(VE.getTypeID(Attr.getValueAsType()));
818       }
819     }
820 
821     Stream.EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
822     Record.clear();
823   }
824 
825   Stream.ExitBlock();
826 }
827 
828 void ModuleBitcodeWriter::writeAttributeTable() {
829   const std::vector<AttributeList> &Attrs = VE.getAttributeLists();
830   if (Attrs.empty()) return;
831 
832   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
833 
834   SmallVector<uint64_t, 64> Record;
835   for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
836     AttributeList AL = Attrs[i];
837     for (unsigned i = AL.index_begin(), e = AL.index_end(); i != e; ++i) {
838       AttributeSet AS = AL.getAttributes(i);
839       if (AS.hasAttributes())
840         Record.push_back(VE.getAttributeGroupID({i, AS}));
841     }
842 
843     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
844     Record.clear();
845   }
846 
847   Stream.ExitBlock();
848 }
849 
850 /// WriteTypeTable - Write out the type table for a module.
851 void ModuleBitcodeWriter::writeTypeTable() {
852   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
853 
854   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
855   SmallVector<uint64_t, 64> TypeVals;
856 
857   uint64_t NumBits = VE.computeBitsRequiredForTypeIndicies();
858 
859   // Abbrev for TYPE_CODE_POINTER.
860   auto Abbv = std::make_shared<BitCodeAbbrev>();
861   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
862   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
863   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
864   unsigned PtrAbbrev = Stream.EmitAbbrev(std::move(Abbv));
865 
866   // Abbrev for TYPE_CODE_OPAQUE_POINTER.
867   Abbv = std::make_shared<BitCodeAbbrev>();
868   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_OPAQUE_POINTER));
869   Abbv->Add(BitCodeAbbrevOp(0)); // Addrspace = 0
870   unsigned OpaquePtrAbbrev = Stream.EmitAbbrev(std::move(Abbv));
871 
872   // Abbrev for TYPE_CODE_FUNCTION.
873   Abbv = std::make_shared<BitCodeAbbrev>();
874   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
875   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
876   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
877   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
878   unsigned FunctionAbbrev = Stream.EmitAbbrev(std::move(Abbv));
879 
880   // Abbrev for TYPE_CODE_STRUCT_ANON.
881   Abbv = std::make_shared<BitCodeAbbrev>();
882   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
883   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
884   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
885   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
886   unsigned StructAnonAbbrev = Stream.EmitAbbrev(std::move(Abbv));
887 
888   // Abbrev for TYPE_CODE_STRUCT_NAME.
889   Abbv = std::make_shared<BitCodeAbbrev>();
890   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
891   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
892   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
893   unsigned StructNameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
894 
895   // Abbrev for TYPE_CODE_STRUCT_NAMED.
896   Abbv = std::make_shared<BitCodeAbbrev>();
897   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
898   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
899   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
900   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
901   unsigned StructNamedAbbrev = Stream.EmitAbbrev(std::move(Abbv));
902 
903   // Abbrev for TYPE_CODE_ARRAY.
904   Abbv = std::make_shared<BitCodeAbbrev>();
905   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
906   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
907   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
908   unsigned ArrayAbbrev = Stream.EmitAbbrev(std::move(Abbv));
909 
910   // Emit an entry count so the reader can reserve space.
911   TypeVals.push_back(TypeList.size());
912   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
913   TypeVals.clear();
914 
915   // Loop over all of the types, emitting each in turn.
916   for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
917     Type *T = TypeList[i];
918     int AbbrevToUse = 0;
919     unsigned Code = 0;
920 
921     switch (T->getTypeID()) {
922     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;      break;
923     case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;      break;
924     case Type::BFloatTyID:    Code = bitc::TYPE_CODE_BFLOAT;    break;
925     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;     break;
926     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE;    break;
927     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80;  break;
928     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128;     break;
929     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
930     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;     break;
931     case Type::MetadataTyID:  Code = bitc::TYPE_CODE_METADATA;  break;
932     case Type::X86_MMXTyID:   Code = bitc::TYPE_CODE_X86_MMX;   break;
933     case Type::X86_AMXTyID:   Code = bitc::TYPE_CODE_X86_AMX;   break;
934     case Type::TokenTyID:     Code = bitc::TYPE_CODE_TOKEN;     break;
935     case Type::IntegerTyID:
936       // INTEGER: [width]
937       Code = bitc::TYPE_CODE_INTEGER;
938       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
939       break;
940     case Type::PointerTyID: {
941       PointerType *PTy = cast<PointerType>(T);
942       unsigned AddressSpace = PTy->getAddressSpace();
943       if (PTy->isOpaque()) {
944         // OPAQUE_POINTER: [address space]
945         Code = bitc::TYPE_CODE_OPAQUE_POINTER;
946         TypeVals.push_back(AddressSpace);
947         if (AddressSpace == 0)
948           AbbrevToUse = OpaquePtrAbbrev;
949       } else {
950         // POINTER: [pointee type, address space]
951         Code = bitc::TYPE_CODE_POINTER;
952         TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
953         TypeVals.push_back(AddressSpace);
954         if (AddressSpace == 0)
955           AbbrevToUse = PtrAbbrev;
956       }
957       break;
958     }
959     case Type::FunctionTyID: {
960       FunctionType *FT = cast<FunctionType>(T);
961       // FUNCTION: [isvararg, retty, paramty x N]
962       Code = bitc::TYPE_CODE_FUNCTION;
963       TypeVals.push_back(FT->isVarArg());
964       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
965       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
966         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
967       AbbrevToUse = FunctionAbbrev;
968       break;
969     }
970     case Type::StructTyID: {
971       StructType *ST = cast<StructType>(T);
972       // STRUCT: [ispacked, eltty x N]
973       TypeVals.push_back(ST->isPacked());
974       // Output all of the element types.
975       for (StructType::element_iterator I = ST->element_begin(),
976            E = ST->element_end(); I != E; ++I)
977         TypeVals.push_back(VE.getTypeID(*I));
978 
979       if (ST->isLiteral()) {
980         Code = bitc::TYPE_CODE_STRUCT_ANON;
981         AbbrevToUse = StructAnonAbbrev;
982       } else {
983         if (ST->isOpaque()) {
984           Code = bitc::TYPE_CODE_OPAQUE;
985         } else {
986           Code = bitc::TYPE_CODE_STRUCT_NAMED;
987           AbbrevToUse = StructNamedAbbrev;
988         }
989 
990         // Emit the name if it is present.
991         if (!ST->getName().empty())
992           writeStringRecord(Stream, bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
993                             StructNameAbbrev);
994       }
995       break;
996     }
997     case Type::ArrayTyID: {
998       ArrayType *AT = cast<ArrayType>(T);
999       // ARRAY: [numelts, eltty]
1000       Code = bitc::TYPE_CODE_ARRAY;
1001       TypeVals.push_back(AT->getNumElements());
1002       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
1003       AbbrevToUse = ArrayAbbrev;
1004       break;
1005     }
1006     case Type::FixedVectorTyID:
1007     case Type::ScalableVectorTyID: {
1008       VectorType *VT = cast<VectorType>(T);
1009       // VECTOR [numelts, eltty] or
1010       //        [numelts, eltty, scalable]
1011       Code = bitc::TYPE_CODE_VECTOR;
1012       TypeVals.push_back(VT->getElementCount().getKnownMinValue());
1013       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
1014       if (isa<ScalableVectorType>(VT))
1015         TypeVals.push_back(true);
1016       break;
1017     }
1018     }
1019 
1020     // Emit the finished record.
1021     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
1022     TypeVals.clear();
1023   }
1024 
1025   Stream.ExitBlock();
1026 }
1027 
1028 static unsigned getEncodedLinkage(const GlobalValue::LinkageTypes Linkage) {
1029   switch (Linkage) {
1030   case GlobalValue::ExternalLinkage:
1031     return 0;
1032   case GlobalValue::WeakAnyLinkage:
1033     return 16;
1034   case GlobalValue::AppendingLinkage:
1035     return 2;
1036   case GlobalValue::InternalLinkage:
1037     return 3;
1038   case GlobalValue::LinkOnceAnyLinkage:
1039     return 18;
1040   case GlobalValue::ExternalWeakLinkage:
1041     return 7;
1042   case GlobalValue::CommonLinkage:
1043     return 8;
1044   case GlobalValue::PrivateLinkage:
1045     return 9;
1046   case GlobalValue::WeakODRLinkage:
1047     return 17;
1048   case GlobalValue::LinkOnceODRLinkage:
1049     return 19;
1050   case GlobalValue::AvailableExternallyLinkage:
1051     return 12;
1052   }
1053   llvm_unreachable("Invalid linkage");
1054 }
1055 
1056 static unsigned getEncodedLinkage(const GlobalValue &GV) {
1057   return getEncodedLinkage(GV.getLinkage());
1058 }
1059 
1060 static uint64_t getEncodedFFlags(FunctionSummary::FFlags Flags) {
1061   uint64_t RawFlags = 0;
1062   RawFlags |= Flags.ReadNone;
1063   RawFlags |= (Flags.ReadOnly << 1);
1064   RawFlags |= (Flags.NoRecurse << 2);
1065   RawFlags |= (Flags.ReturnDoesNotAlias << 3);
1066   RawFlags |= (Flags.NoInline << 4);
1067   RawFlags |= (Flags.AlwaysInline << 5);
1068   return RawFlags;
1069 }
1070 
1071 // Decode the flags for GlobalValue in the summary. See getDecodedGVSummaryFlags
1072 // in BitcodeReader.cpp.
1073 static uint64_t getEncodedGVSummaryFlags(GlobalValueSummary::GVFlags Flags) {
1074   uint64_t RawFlags = 0;
1075 
1076   RawFlags |= Flags.NotEligibleToImport; // bool
1077   RawFlags |= (Flags.Live << 1);
1078   RawFlags |= (Flags.DSOLocal << 2);
1079   RawFlags |= (Flags.CanAutoHide << 3);
1080 
1081   // Linkage don't need to be remapped at that time for the summary. Any future
1082   // change to the getEncodedLinkage() function will need to be taken into
1083   // account here as well.
1084   RawFlags = (RawFlags << 4) | Flags.Linkage; // 4 bits
1085 
1086   RawFlags |= (Flags.Visibility << 8); // 2 bits
1087 
1088   return RawFlags;
1089 }
1090 
1091 static uint64_t getEncodedGVarFlags(GlobalVarSummary::GVarFlags Flags) {
1092   uint64_t RawFlags = Flags.MaybeReadOnly | (Flags.MaybeWriteOnly << 1) |
1093                       (Flags.Constant << 2) | Flags.VCallVisibility << 3;
1094   return RawFlags;
1095 }
1096 
1097 static unsigned getEncodedVisibility(const GlobalValue &GV) {
1098   switch (GV.getVisibility()) {
1099   case GlobalValue::DefaultVisibility:   return 0;
1100   case GlobalValue::HiddenVisibility:    return 1;
1101   case GlobalValue::ProtectedVisibility: return 2;
1102   }
1103   llvm_unreachable("Invalid visibility");
1104 }
1105 
1106 static unsigned getEncodedDLLStorageClass(const GlobalValue &GV) {
1107   switch (GV.getDLLStorageClass()) {
1108   case GlobalValue::DefaultStorageClass:   return 0;
1109   case GlobalValue::DLLImportStorageClass: return 1;
1110   case GlobalValue::DLLExportStorageClass: return 2;
1111   }
1112   llvm_unreachable("Invalid DLL storage class");
1113 }
1114 
1115 static unsigned getEncodedThreadLocalMode(const GlobalValue &GV) {
1116   switch (GV.getThreadLocalMode()) {
1117     case GlobalVariable::NotThreadLocal:         return 0;
1118     case GlobalVariable::GeneralDynamicTLSModel: return 1;
1119     case GlobalVariable::LocalDynamicTLSModel:   return 2;
1120     case GlobalVariable::InitialExecTLSModel:    return 3;
1121     case GlobalVariable::LocalExecTLSModel:      return 4;
1122   }
1123   llvm_unreachable("Invalid TLS model");
1124 }
1125 
1126 static unsigned getEncodedComdatSelectionKind(const Comdat &C) {
1127   switch (C.getSelectionKind()) {
1128   case Comdat::Any:
1129     return bitc::COMDAT_SELECTION_KIND_ANY;
1130   case Comdat::ExactMatch:
1131     return bitc::COMDAT_SELECTION_KIND_EXACT_MATCH;
1132   case Comdat::Largest:
1133     return bitc::COMDAT_SELECTION_KIND_LARGEST;
1134   case Comdat::NoDeduplicate:
1135     return bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES;
1136   case Comdat::SameSize:
1137     return bitc::COMDAT_SELECTION_KIND_SAME_SIZE;
1138   }
1139   llvm_unreachable("Invalid selection kind");
1140 }
1141 
1142 static unsigned getEncodedUnnamedAddr(const GlobalValue &GV) {
1143   switch (GV.getUnnamedAddr()) {
1144   case GlobalValue::UnnamedAddr::None:   return 0;
1145   case GlobalValue::UnnamedAddr::Local:  return 2;
1146   case GlobalValue::UnnamedAddr::Global: return 1;
1147   }
1148   llvm_unreachable("Invalid unnamed_addr");
1149 }
1150 
1151 size_t ModuleBitcodeWriter::addToStrtab(StringRef Str) {
1152   if (GenerateHash)
1153     Hasher.update(Str);
1154   return StrtabBuilder.add(Str);
1155 }
1156 
1157 void ModuleBitcodeWriter::writeComdats() {
1158   SmallVector<unsigned, 64> Vals;
1159   for (const Comdat *C : VE.getComdats()) {
1160     // COMDAT: [strtab offset, strtab size, selection_kind]
1161     Vals.push_back(addToStrtab(C->getName()));
1162     Vals.push_back(C->getName().size());
1163     Vals.push_back(getEncodedComdatSelectionKind(*C));
1164     Stream.EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
1165     Vals.clear();
1166   }
1167 }
1168 
1169 /// Write a record that will eventually hold the word offset of the
1170 /// module-level VST. For now the offset is 0, which will be backpatched
1171 /// after the real VST is written. Saves the bit offset to backpatch.
1172 void ModuleBitcodeWriter::writeValueSymbolTableForwardDecl() {
1173   // Write a placeholder value in for the offset of the real VST,
1174   // which is written after the function blocks so that it can include
1175   // the offset of each function. The placeholder offset will be
1176   // updated when the real VST is written.
1177   auto Abbv = std::make_shared<BitCodeAbbrev>();
1178   Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_VSTOFFSET));
1179   // Blocks are 32-bit aligned, so we can use a 32-bit word offset to
1180   // hold the real VST offset. Must use fixed instead of VBR as we don't
1181   // know how many VBR chunks to reserve ahead of time.
1182   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
1183   unsigned VSTOffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1184 
1185   // Emit the placeholder
1186   uint64_t Vals[] = {bitc::MODULE_CODE_VSTOFFSET, 0};
1187   Stream.EmitRecordWithAbbrev(VSTOffsetAbbrev, Vals);
1188 
1189   // Compute and save the bit offset to the placeholder, which will be
1190   // patched when the real VST is written. We can simply subtract the 32-bit
1191   // fixed size from the current bit number to get the location to backpatch.
1192   VSTOffsetPlaceholder = Stream.GetCurrentBitNo() - 32;
1193 }
1194 
1195 enum StringEncoding { SE_Char6, SE_Fixed7, SE_Fixed8 };
1196 
1197 /// Determine the encoding to use for the given string name and length.
1198 static StringEncoding getStringEncoding(StringRef Str) {
1199   bool isChar6 = true;
1200   for (char C : Str) {
1201     if (isChar6)
1202       isChar6 = BitCodeAbbrevOp::isChar6(C);
1203     if ((unsigned char)C & 128)
1204       // don't bother scanning the rest.
1205       return SE_Fixed8;
1206   }
1207   if (isChar6)
1208     return SE_Char6;
1209   return SE_Fixed7;
1210 }
1211 
1212 /// Emit top-level description of module, including target triple, inline asm,
1213 /// descriptors for global variables, and function prototype info.
1214 /// Returns the bit offset to backpatch with the location of the real VST.
1215 void ModuleBitcodeWriter::writeModuleInfo() {
1216   // Emit various pieces of data attached to a module.
1217   if (!M.getTargetTriple().empty())
1218     writeStringRecord(Stream, bitc::MODULE_CODE_TRIPLE, M.getTargetTriple(),
1219                       0 /*TODO*/);
1220   const std::string &DL = M.getDataLayoutStr();
1221   if (!DL.empty())
1222     writeStringRecord(Stream, bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/);
1223   if (!M.getModuleInlineAsm().empty())
1224     writeStringRecord(Stream, bitc::MODULE_CODE_ASM, M.getModuleInlineAsm(),
1225                       0 /*TODO*/);
1226 
1227   // Emit information about sections and GC, computing how many there are. Also
1228   // compute the maximum alignment value.
1229   std::map<std::string, unsigned> SectionMap;
1230   std::map<std::string, unsigned> GCMap;
1231   MaybeAlign MaxAlignment;
1232   unsigned MaxGlobalType = 0;
1233   const auto UpdateMaxAlignment = [&MaxAlignment](const MaybeAlign A) {
1234     if (A)
1235       MaxAlignment = !MaxAlignment ? *A : std::max(*MaxAlignment, *A);
1236   };
1237   for (const GlobalVariable &GV : M.globals()) {
1238     UpdateMaxAlignment(GV.getAlign());
1239     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getValueType()));
1240     if (GV.hasSection()) {
1241       // Give section names unique ID's.
1242       unsigned &Entry = SectionMap[std::string(GV.getSection())];
1243       if (!Entry) {
1244         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
1245                           0 /*TODO*/);
1246         Entry = SectionMap.size();
1247       }
1248     }
1249   }
1250   for (const Function &F : M) {
1251     UpdateMaxAlignment(F.getAlign());
1252     if (F.hasSection()) {
1253       // Give section names unique ID's.
1254       unsigned &Entry = SectionMap[std::string(F.getSection())];
1255       if (!Entry) {
1256         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
1257                           0 /*TODO*/);
1258         Entry = SectionMap.size();
1259       }
1260     }
1261     if (F.hasGC()) {
1262       // Same for GC names.
1263       unsigned &Entry = GCMap[F.getGC()];
1264       if (!Entry) {
1265         writeStringRecord(Stream, bitc::MODULE_CODE_GCNAME, F.getGC(),
1266                           0 /*TODO*/);
1267         Entry = GCMap.size();
1268       }
1269     }
1270   }
1271 
1272   // Emit abbrev for globals, now that we know # sections and max alignment.
1273   unsigned SimpleGVarAbbrev = 0;
1274   if (!M.global_empty()) {
1275     // Add an abbrev for common globals with no visibility or thread localness.
1276     auto Abbv = std::make_shared<BitCodeAbbrev>();
1277     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
1278     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1279     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1280     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1281                               Log2_32_Ceil(MaxGlobalType+1)));
1282     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddrSpace << 2
1283                                                            //| explicitType << 1
1284                                                            //| constant
1285     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Initializer.
1286     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // Linkage.
1287     if (!MaxAlignment)                                     // Alignment.
1288       Abbv->Add(BitCodeAbbrevOp(0));
1289     else {
1290       unsigned MaxEncAlignment = getEncodedAlign(MaxAlignment);
1291       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1292                                Log2_32_Ceil(MaxEncAlignment+1)));
1293     }
1294     if (SectionMap.empty())                                    // Section.
1295       Abbv->Add(BitCodeAbbrevOp(0));
1296     else
1297       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1298                                Log2_32_Ceil(SectionMap.size()+1)));
1299     // Don't bother emitting vis + thread local.
1300     SimpleGVarAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1301   }
1302 
1303   SmallVector<unsigned, 64> Vals;
1304   // Emit the module's source file name.
1305   {
1306     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
1307     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
1308     if (Bits == SE_Char6)
1309       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
1310     else if (Bits == SE_Fixed7)
1311       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
1312 
1313     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
1314     auto Abbv = std::make_shared<BitCodeAbbrev>();
1315     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
1316     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1317     Abbv->Add(AbbrevOpToUse);
1318     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1319 
1320     for (const auto P : M.getSourceFileName())
1321       Vals.push_back((unsigned char)P);
1322 
1323     // Emit the finished record.
1324     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
1325     Vals.clear();
1326   }
1327 
1328   // Emit the global variable information.
1329   for (const GlobalVariable &GV : M.globals()) {
1330     unsigned AbbrevToUse = 0;
1331 
1332     // GLOBALVAR: [strtab offset, strtab size, type, isconst, initid,
1333     //             linkage, alignment, section, visibility, threadlocal,
1334     //             unnamed_addr, externally_initialized, dllstorageclass,
1335     //             comdat, attributes, DSO_Local]
1336     Vals.push_back(addToStrtab(GV.getName()));
1337     Vals.push_back(GV.getName().size());
1338     Vals.push_back(VE.getTypeID(GV.getValueType()));
1339     Vals.push_back(GV.getType()->getAddressSpace() << 2 | 2 | GV.isConstant());
1340     Vals.push_back(GV.isDeclaration() ? 0 :
1341                    (VE.getValueID(GV.getInitializer()) + 1));
1342     Vals.push_back(getEncodedLinkage(GV));
1343     Vals.push_back(getEncodedAlign(GV.getAlign()));
1344     Vals.push_back(GV.hasSection() ? SectionMap[std::string(GV.getSection())]
1345                                    : 0);
1346     if (GV.isThreadLocal() ||
1347         GV.getVisibility() != GlobalValue::DefaultVisibility ||
1348         GV.getUnnamedAddr() != GlobalValue::UnnamedAddr::None ||
1349         GV.isExternallyInitialized() ||
1350         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
1351         GV.hasComdat() ||
1352         GV.hasAttributes() ||
1353         GV.isDSOLocal() ||
1354         GV.hasPartition()) {
1355       Vals.push_back(getEncodedVisibility(GV));
1356       Vals.push_back(getEncodedThreadLocalMode(GV));
1357       Vals.push_back(getEncodedUnnamedAddr(GV));
1358       Vals.push_back(GV.isExternallyInitialized());
1359       Vals.push_back(getEncodedDLLStorageClass(GV));
1360       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
1361 
1362       auto AL = GV.getAttributesAsList(AttributeList::FunctionIndex);
1363       Vals.push_back(VE.getAttributeListID(AL));
1364 
1365       Vals.push_back(GV.isDSOLocal());
1366       Vals.push_back(addToStrtab(GV.getPartition()));
1367       Vals.push_back(GV.getPartition().size());
1368     } else {
1369       AbbrevToUse = SimpleGVarAbbrev;
1370     }
1371 
1372     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
1373     Vals.clear();
1374   }
1375 
1376   // Emit the function proto information.
1377   for (const Function &F : M) {
1378     // FUNCTION:  [strtab offset, strtab size, type, callingconv, isproto,
1379     //             linkage, paramattrs, alignment, section, visibility, gc,
1380     //             unnamed_addr, prologuedata, dllstorageclass, comdat,
1381     //             prefixdata, personalityfn, DSO_Local, addrspace]
1382     Vals.push_back(addToStrtab(F.getName()));
1383     Vals.push_back(F.getName().size());
1384     Vals.push_back(VE.getTypeID(F.getFunctionType()));
1385     Vals.push_back(F.getCallingConv());
1386     Vals.push_back(F.isDeclaration());
1387     Vals.push_back(getEncodedLinkage(F));
1388     Vals.push_back(VE.getAttributeListID(F.getAttributes()));
1389     Vals.push_back(getEncodedAlign(F.getAlign()));
1390     Vals.push_back(F.hasSection() ? SectionMap[std::string(F.getSection())]
1391                                   : 0);
1392     Vals.push_back(getEncodedVisibility(F));
1393     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
1394     Vals.push_back(getEncodedUnnamedAddr(F));
1395     Vals.push_back(F.hasPrologueData() ? (VE.getValueID(F.getPrologueData()) + 1)
1396                                        : 0);
1397     Vals.push_back(getEncodedDLLStorageClass(F));
1398     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
1399     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
1400                                      : 0);
1401     Vals.push_back(
1402         F.hasPersonalityFn() ? (VE.getValueID(F.getPersonalityFn()) + 1) : 0);
1403 
1404     Vals.push_back(F.isDSOLocal());
1405     Vals.push_back(F.getAddressSpace());
1406     Vals.push_back(addToStrtab(F.getPartition()));
1407     Vals.push_back(F.getPartition().size());
1408 
1409     unsigned AbbrevToUse = 0;
1410     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
1411     Vals.clear();
1412   }
1413 
1414   // Emit the alias information.
1415   for (const GlobalAlias &A : M.aliases()) {
1416     // ALIAS: [strtab offset, strtab size, alias type, aliasee val#, linkage,
1417     //         visibility, dllstorageclass, threadlocal, unnamed_addr,
1418     //         DSO_Local]
1419     Vals.push_back(addToStrtab(A.getName()));
1420     Vals.push_back(A.getName().size());
1421     Vals.push_back(VE.getTypeID(A.getValueType()));
1422     Vals.push_back(A.getType()->getAddressSpace());
1423     Vals.push_back(VE.getValueID(A.getAliasee()));
1424     Vals.push_back(getEncodedLinkage(A));
1425     Vals.push_back(getEncodedVisibility(A));
1426     Vals.push_back(getEncodedDLLStorageClass(A));
1427     Vals.push_back(getEncodedThreadLocalMode(A));
1428     Vals.push_back(getEncodedUnnamedAddr(A));
1429     Vals.push_back(A.isDSOLocal());
1430     Vals.push_back(addToStrtab(A.getPartition()));
1431     Vals.push_back(A.getPartition().size());
1432 
1433     unsigned AbbrevToUse = 0;
1434     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
1435     Vals.clear();
1436   }
1437 
1438   // Emit the ifunc information.
1439   for (const GlobalIFunc &I : M.ifuncs()) {
1440     // IFUNC: [strtab offset, strtab size, ifunc type, address space, resolver
1441     //         val#, linkage, visibility, DSO_Local]
1442     Vals.push_back(addToStrtab(I.getName()));
1443     Vals.push_back(I.getName().size());
1444     Vals.push_back(VE.getTypeID(I.getValueType()));
1445     Vals.push_back(I.getType()->getAddressSpace());
1446     Vals.push_back(VE.getValueID(I.getResolver()));
1447     Vals.push_back(getEncodedLinkage(I));
1448     Vals.push_back(getEncodedVisibility(I));
1449     Vals.push_back(I.isDSOLocal());
1450     Vals.push_back(addToStrtab(I.getPartition()));
1451     Vals.push_back(I.getPartition().size());
1452     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
1453     Vals.clear();
1454   }
1455 
1456   writeValueSymbolTableForwardDecl();
1457 }
1458 
1459 static uint64_t getOptimizationFlags(const Value *V) {
1460   uint64_t Flags = 0;
1461 
1462   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
1463     if (OBO->hasNoSignedWrap())
1464       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
1465     if (OBO->hasNoUnsignedWrap())
1466       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
1467   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
1468     if (PEO->isExact())
1469       Flags |= 1 << bitc::PEO_EXACT;
1470   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
1471     if (FPMO->hasAllowReassoc())
1472       Flags |= bitc::AllowReassoc;
1473     if (FPMO->hasNoNaNs())
1474       Flags |= bitc::NoNaNs;
1475     if (FPMO->hasNoInfs())
1476       Flags |= bitc::NoInfs;
1477     if (FPMO->hasNoSignedZeros())
1478       Flags |= bitc::NoSignedZeros;
1479     if (FPMO->hasAllowReciprocal())
1480       Flags |= bitc::AllowReciprocal;
1481     if (FPMO->hasAllowContract())
1482       Flags |= bitc::AllowContract;
1483     if (FPMO->hasApproxFunc())
1484       Flags |= bitc::ApproxFunc;
1485   }
1486 
1487   return Flags;
1488 }
1489 
1490 void ModuleBitcodeWriter::writeValueAsMetadata(
1491     const ValueAsMetadata *MD, SmallVectorImpl<uint64_t> &Record) {
1492   // Mimic an MDNode with a value as one operand.
1493   Value *V = MD->getValue();
1494   Record.push_back(VE.getTypeID(V->getType()));
1495   Record.push_back(VE.getValueID(V));
1496   Stream.EmitRecord(bitc::METADATA_VALUE, Record, 0);
1497   Record.clear();
1498 }
1499 
1500 void ModuleBitcodeWriter::writeMDTuple(const MDTuple *N,
1501                                        SmallVectorImpl<uint64_t> &Record,
1502                                        unsigned Abbrev) {
1503   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
1504     Metadata *MD = N->getOperand(i);
1505     assert(!(MD && isa<LocalAsMetadata>(MD)) &&
1506            "Unexpected function-local metadata");
1507     Record.push_back(VE.getMetadataOrNullID(MD));
1508   }
1509   Stream.EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
1510                                     : bitc::METADATA_NODE,
1511                     Record, Abbrev);
1512   Record.clear();
1513 }
1514 
1515 unsigned ModuleBitcodeWriter::createDILocationAbbrev() {
1516   // Assume the column is usually under 128, and always output the inlined-at
1517   // location (it's never more expensive than building an array size 1).
1518   auto Abbv = std::make_shared<BitCodeAbbrev>();
1519   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
1520   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1521   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1522   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1523   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1524   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1525   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1526   return Stream.EmitAbbrev(std::move(Abbv));
1527 }
1528 
1529 void ModuleBitcodeWriter::writeDILocation(const DILocation *N,
1530                                           SmallVectorImpl<uint64_t> &Record,
1531                                           unsigned &Abbrev) {
1532   if (!Abbrev)
1533     Abbrev = createDILocationAbbrev();
1534 
1535   Record.push_back(N->isDistinct());
1536   Record.push_back(N->getLine());
1537   Record.push_back(N->getColumn());
1538   Record.push_back(VE.getMetadataID(N->getScope()));
1539   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
1540   Record.push_back(N->isImplicitCode());
1541 
1542   Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
1543   Record.clear();
1544 }
1545 
1546 unsigned ModuleBitcodeWriter::createGenericDINodeAbbrev() {
1547   // Assume the column is usually under 128, and always output the inlined-at
1548   // location (it's never more expensive than building an array size 1).
1549   auto Abbv = std::make_shared<BitCodeAbbrev>();
1550   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
1551   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1552   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1553   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1554   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1555   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1556   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1557   return Stream.EmitAbbrev(std::move(Abbv));
1558 }
1559 
1560 void ModuleBitcodeWriter::writeGenericDINode(const GenericDINode *N,
1561                                              SmallVectorImpl<uint64_t> &Record,
1562                                              unsigned &Abbrev) {
1563   if (!Abbrev)
1564     Abbrev = createGenericDINodeAbbrev();
1565 
1566   Record.push_back(N->isDistinct());
1567   Record.push_back(N->getTag());
1568   Record.push_back(0); // Per-tag version field; unused for now.
1569 
1570   for (auto &I : N->operands())
1571     Record.push_back(VE.getMetadataOrNullID(I));
1572 
1573   Stream.EmitRecord(bitc::METADATA_GENERIC_DEBUG, Record, Abbrev);
1574   Record.clear();
1575 }
1576 
1577 void ModuleBitcodeWriter::writeDISubrange(const DISubrange *N,
1578                                           SmallVectorImpl<uint64_t> &Record,
1579                                           unsigned Abbrev) {
1580   const uint64_t Version = 2 << 1;
1581   Record.push_back((uint64_t)N->isDistinct() | Version);
1582   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1583   Record.push_back(VE.getMetadataOrNullID(N->getRawLowerBound()));
1584   Record.push_back(VE.getMetadataOrNullID(N->getRawUpperBound()));
1585   Record.push_back(VE.getMetadataOrNullID(N->getRawStride()));
1586 
1587   Stream.EmitRecord(bitc::METADATA_SUBRANGE, Record, Abbrev);
1588   Record.clear();
1589 }
1590 
1591 void ModuleBitcodeWriter::writeDIGenericSubrange(
1592     const DIGenericSubrange *N, SmallVectorImpl<uint64_t> &Record,
1593     unsigned Abbrev) {
1594   Record.push_back((uint64_t)N->isDistinct());
1595   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1596   Record.push_back(VE.getMetadataOrNullID(N->getRawLowerBound()));
1597   Record.push_back(VE.getMetadataOrNullID(N->getRawUpperBound()));
1598   Record.push_back(VE.getMetadataOrNullID(N->getRawStride()));
1599 
1600   Stream.EmitRecord(bitc::METADATA_GENERIC_SUBRANGE, Record, Abbrev);
1601   Record.clear();
1602 }
1603 
1604 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
1605   if ((int64_t)V >= 0)
1606     Vals.push_back(V << 1);
1607   else
1608     Vals.push_back((-V << 1) | 1);
1609 }
1610 
1611 static void emitWideAPInt(SmallVectorImpl<uint64_t> &Vals, const APInt &A) {
1612   // We have an arbitrary precision integer value to write whose
1613   // bit width is > 64. However, in canonical unsigned integer
1614   // format it is likely that the high bits are going to be zero.
1615   // So, we only write the number of active words.
1616   unsigned NumWords = A.getActiveWords();
1617   const uint64_t *RawData = A.getRawData();
1618   for (unsigned i = 0; i < NumWords; i++)
1619     emitSignedInt64(Vals, RawData[i]);
1620 }
1621 
1622 void ModuleBitcodeWriter::writeDIEnumerator(const DIEnumerator *N,
1623                                             SmallVectorImpl<uint64_t> &Record,
1624                                             unsigned Abbrev) {
1625   const uint64_t IsBigInt = 1 << 2;
1626   Record.push_back(IsBigInt | (N->isUnsigned() << 1) | N->isDistinct());
1627   Record.push_back(N->getValue().getBitWidth());
1628   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1629   emitWideAPInt(Record, N->getValue());
1630 
1631   Stream.EmitRecord(bitc::METADATA_ENUMERATOR, Record, Abbrev);
1632   Record.clear();
1633 }
1634 
1635 void ModuleBitcodeWriter::writeDIBasicType(const DIBasicType *N,
1636                                            SmallVectorImpl<uint64_t> &Record,
1637                                            unsigned Abbrev) {
1638   Record.push_back(N->isDistinct());
1639   Record.push_back(N->getTag());
1640   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1641   Record.push_back(N->getSizeInBits());
1642   Record.push_back(N->getAlignInBits());
1643   Record.push_back(N->getEncoding());
1644   Record.push_back(N->getFlags());
1645 
1646   Stream.EmitRecord(bitc::METADATA_BASIC_TYPE, Record, Abbrev);
1647   Record.clear();
1648 }
1649 
1650 void ModuleBitcodeWriter::writeDIStringType(const DIStringType *N,
1651                                             SmallVectorImpl<uint64_t> &Record,
1652                                             unsigned Abbrev) {
1653   Record.push_back(N->isDistinct());
1654   Record.push_back(N->getTag());
1655   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1656   Record.push_back(VE.getMetadataOrNullID(N->getStringLength()));
1657   Record.push_back(VE.getMetadataOrNullID(N->getStringLengthExp()));
1658   Record.push_back(N->getSizeInBits());
1659   Record.push_back(N->getAlignInBits());
1660   Record.push_back(N->getEncoding());
1661 
1662   Stream.EmitRecord(bitc::METADATA_STRING_TYPE, Record, Abbrev);
1663   Record.clear();
1664 }
1665 
1666 void ModuleBitcodeWriter::writeDIDerivedType(const DIDerivedType *N,
1667                                              SmallVectorImpl<uint64_t> &Record,
1668                                              unsigned Abbrev) {
1669   Record.push_back(N->isDistinct());
1670   Record.push_back(N->getTag());
1671   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1672   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1673   Record.push_back(N->getLine());
1674   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1675   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1676   Record.push_back(N->getSizeInBits());
1677   Record.push_back(N->getAlignInBits());
1678   Record.push_back(N->getOffsetInBits());
1679   Record.push_back(N->getFlags());
1680   Record.push_back(VE.getMetadataOrNullID(N->getExtraData()));
1681 
1682   // DWARF address space is encoded as N->getDWARFAddressSpace() + 1. 0 means
1683   // that there is no DWARF address space associated with DIDerivedType.
1684   if (const auto &DWARFAddressSpace = N->getDWARFAddressSpace())
1685     Record.push_back(*DWARFAddressSpace + 1);
1686   else
1687     Record.push_back(0);
1688 
1689   Stream.EmitRecord(bitc::METADATA_DERIVED_TYPE, Record, Abbrev);
1690   Record.clear();
1691 }
1692 
1693 void ModuleBitcodeWriter::writeDICompositeType(
1694     const DICompositeType *N, SmallVectorImpl<uint64_t> &Record,
1695     unsigned Abbrev) {
1696   const unsigned IsNotUsedInOldTypeRef = 0x2;
1697   Record.push_back(IsNotUsedInOldTypeRef | (unsigned)N->isDistinct());
1698   Record.push_back(N->getTag());
1699   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1700   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1701   Record.push_back(N->getLine());
1702   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1703   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1704   Record.push_back(N->getSizeInBits());
1705   Record.push_back(N->getAlignInBits());
1706   Record.push_back(N->getOffsetInBits());
1707   Record.push_back(N->getFlags());
1708   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1709   Record.push_back(N->getRuntimeLang());
1710   Record.push_back(VE.getMetadataOrNullID(N->getVTableHolder()));
1711   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1712   Record.push_back(VE.getMetadataOrNullID(N->getRawIdentifier()));
1713   Record.push_back(VE.getMetadataOrNullID(N->getDiscriminator()));
1714   Record.push_back(VE.getMetadataOrNullID(N->getRawDataLocation()));
1715   Record.push_back(VE.getMetadataOrNullID(N->getRawAssociated()));
1716   Record.push_back(VE.getMetadataOrNullID(N->getRawAllocated()));
1717   Record.push_back(VE.getMetadataOrNullID(N->getRawRank()));
1718 
1719   Stream.EmitRecord(bitc::METADATA_COMPOSITE_TYPE, Record, Abbrev);
1720   Record.clear();
1721 }
1722 
1723 void ModuleBitcodeWriter::writeDISubroutineType(
1724     const DISubroutineType *N, SmallVectorImpl<uint64_t> &Record,
1725     unsigned Abbrev) {
1726   const unsigned HasNoOldTypeRefs = 0x2;
1727   Record.push_back(HasNoOldTypeRefs | (unsigned)N->isDistinct());
1728   Record.push_back(N->getFlags());
1729   Record.push_back(VE.getMetadataOrNullID(N->getTypeArray().get()));
1730   Record.push_back(N->getCC());
1731 
1732   Stream.EmitRecord(bitc::METADATA_SUBROUTINE_TYPE, Record, Abbrev);
1733   Record.clear();
1734 }
1735 
1736 void ModuleBitcodeWriter::writeDIFile(const DIFile *N,
1737                                       SmallVectorImpl<uint64_t> &Record,
1738                                       unsigned Abbrev) {
1739   Record.push_back(N->isDistinct());
1740   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
1741   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
1742   if (N->getRawChecksum()) {
1743     Record.push_back(N->getRawChecksum()->Kind);
1744     Record.push_back(VE.getMetadataOrNullID(N->getRawChecksum()->Value));
1745   } else {
1746     // Maintain backwards compatibility with the old internal representation of
1747     // CSK_None in ChecksumKind by writing nulls here when Checksum is None.
1748     Record.push_back(0);
1749     Record.push_back(VE.getMetadataOrNullID(nullptr));
1750   }
1751   auto Source = N->getRawSource();
1752   if (Source)
1753     Record.push_back(VE.getMetadataOrNullID(*Source));
1754 
1755   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
1756   Record.clear();
1757 }
1758 
1759 void ModuleBitcodeWriter::writeDICompileUnit(const DICompileUnit *N,
1760                                              SmallVectorImpl<uint64_t> &Record,
1761                                              unsigned Abbrev) {
1762   assert(N->isDistinct() && "Expected distinct compile units");
1763   Record.push_back(/* IsDistinct */ true);
1764   Record.push_back(N->getSourceLanguage());
1765   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1766   Record.push_back(VE.getMetadataOrNullID(N->getRawProducer()));
1767   Record.push_back(N->isOptimized());
1768   Record.push_back(VE.getMetadataOrNullID(N->getRawFlags()));
1769   Record.push_back(N->getRuntimeVersion());
1770   Record.push_back(VE.getMetadataOrNullID(N->getRawSplitDebugFilename()));
1771   Record.push_back(N->getEmissionKind());
1772   Record.push_back(VE.getMetadataOrNullID(N->getEnumTypes().get()));
1773   Record.push_back(VE.getMetadataOrNullID(N->getRetainedTypes().get()));
1774   Record.push_back(/* subprograms */ 0);
1775   Record.push_back(VE.getMetadataOrNullID(N->getGlobalVariables().get()));
1776   Record.push_back(VE.getMetadataOrNullID(N->getImportedEntities().get()));
1777   Record.push_back(N->getDWOId());
1778   Record.push_back(VE.getMetadataOrNullID(N->getMacros().get()));
1779   Record.push_back(N->getSplitDebugInlining());
1780   Record.push_back(N->getDebugInfoForProfiling());
1781   Record.push_back((unsigned)N->getNameTableKind());
1782   Record.push_back(N->getRangesBaseAddress());
1783   Record.push_back(VE.getMetadataOrNullID(N->getRawSysRoot()));
1784   Record.push_back(VE.getMetadataOrNullID(N->getRawSDK()));
1785 
1786   Stream.EmitRecord(bitc::METADATA_COMPILE_UNIT, Record, Abbrev);
1787   Record.clear();
1788 }
1789 
1790 void ModuleBitcodeWriter::writeDISubprogram(const DISubprogram *N,
1791                                             SmallVectorImpl<uint64_t> &Record,
1792                                             unsigned Abbrev) {
1793   const uint64_t HasUnitFlag = 1 << 1;
1794   const uint64_t HasSPFlagsFlag = 1 << 2;
1795   Record.push_back(uint64_t(N->isDistinct()) | HasUnitFlag | HasSPFlagsFlag);
1796   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1797   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1798   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1799   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1800   Record.push_back(N->getLine());
1801   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1802   Record.push_back(N->getScopeLine());
1803   Record.push_back(VE.getMetadataOrNullID(N->getContainingType()));
1804   Record.push_back(N->getSPFlags());
1805   Record.push_back(N->getVirtualIndex());
1806   Record.push_back(N->getFlags());
1807   Record.push_back(VE.getMetadataOrNullID(N->getRawUnit()));
1808   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1809   Record.push_back(VE.getMetadataOrNullID(N->getDeclaration()));
1810   Record.push_back(VE.getMetadataOrNullID(N->getRetainedNodes().get()));
1811   Record.push_back(N->getThisAdjustment());
1812   Record.push_back(VE.getMetadataOrNullID(N->getThrownTypes().get()));
1813 
1814   Stream.EmitRecord(bitc::METADATA_SUBPROGRAM, Record, Abbrev);
1815   Record.clear();
1816 }
1817 
1818 void ModuleBitcodeWriter::writeDILexicalBlock(const DILexicalBlock *N,
1819                                               SmallVectorImpl<uint64_t> &Record,
1820                                               unsigned Abbrev) {
1821   Record.push_back(N->isDistinct());
1822   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1823   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1824   Record.push_back(N->getLine());
1825   Record.push_back(N->getColumn());
1826 
1827   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK, Record, Abbrev);
1828   Record.clear();
1829 }
1830 
1831 void ModuleBitcodeWriter::writeDILexicalBlockFile(
1832     const DILexicalBlockFile *N, SmallVectorImpl<uint64_t> &Record,
1833     unsigned Abbrev) {
1834   Record.push_back(N->isDistinct());
1835   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1836   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1837   Record.push_back(N->getDiscriminator());
1838 
1839   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK_FILE, Record, Abbrev);
1840   Record.clear();
1841 }
1842 
1843 void ModuleBitcodeWriter::writeDICommonBlock(const DICommonBlock *N,
1844                                              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->getDecl()));
1849   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1850   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1851   Record.push_back(N->getLineNo());
1852 
1853   Stream.EmitRecord(bitc::METADATA_COMMON_BLOCK, Record, Abbrev);
1854   Record.clear();
1855 }
1856 
1857 void ModuleBitcodeWriter::writeDINamespace(const DINamespace *N,
1858                                            SmallVectorImpl<uint64_t> &Record,
1859                                            unsigned Abbrev) {
1860   Record.push_back(N->isDistinct() | N->getExportSymbols() << 1);
1861   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1862   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1863 
1864   Stream.EmitRecord(bitc::METADATA_NAMESPACE, Record, Abbrev);
1865   Record.clear();
1866 }
1867 
1868 void ModuleBitcodeWriter::writeDIMacro(const DIMacro *N,
1869                                        SmallVectorImpl<uint64_t> &Record,
1870                                        unsigned Abbrev) {
1871   Record.push_back(N->isDistinct());
1872   Record.push_back(N->getMacinfoType());
1873   Record.push_back(N->getLine());
1874   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1875   Record.push_back(VE.getMetadataOrNullID(N->getRawValue()));
1876 
1877   Stream.EmitRecord(bitc::METADATA_MACRO, Record, Abbrev);
1878   Record.clear();
1879 }
1880 
1881 void ModuleBitcodeWriter::writeDIMacroFile(const DIMacroFile *N,
1882                                            SmallVectorImpl<uint64_t> &Record,
1883                                            unsigned Abbrev) {
1884   Record.push_back(N->isDistinct());
1885   Record.push_back(N->getMacinfoType());
1886   Record.push_back(N->getLine());
1887   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1888   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1889 
1890   Stream.EmitRecord(bitc::METADATA_MACRO_FILE, Record, Abbrev);
1891   Record.clear();
1892 }
1893 
1894 void ModuleBitcodeWriter::writeDIArgList(const DIArgList *N,
1895                                          SmallVectorImpl<uint64_t> &Record,
1896                                          unsigned Abbrev) {
1897   Record.reserve(N->getArgs().size());
1898   for (ValueAsMetadata *MD : N->getArgs())
1899     Record.push_back(VE.getMetadataID(MD));
1900 
1901   Stream.EmitRecord(bitc::METADATA_ARG_LIST, Record, Abbrev);
1902   Record.clear();
1903 }
1904 
1905 void ModuleBitcodeWriter::writeDIModule(const DIModule *N,
1906                                         SmallVectorImpl<uint64_t> &Record,
1907                                         unsigned Abbrev) {
1908   Record.push_back(N->isDistinct());
1909   for (auto &I : N->operands())
1910     Record.push_back(VE.getMetadataOrNullID(I));
1911   Record.push_back(N->getLineNo());
1912   Record.push_back(N->getIsDecl());
1913 
1914   Stream.EmitRecord(bitc::METADATA_MODULE, Record, Abbrev);
1915   Record.clear();
1916 }
1917 
1918 void ModuleBitcodeWriter::writeDITemplateTypeParameter(
1919     const DITemplateTypeParameter *N, SmallVectorImpl<uint64_t> &Record,
1920     unsigned Abbrev) {
1921   Record.push_back(N->isDistinct());
1922   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1923   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1924   Record.push_back(N->isDefault());
1925 
1926   Stream.EmitRecord(bitc::METADATA_TEMPLATE_TYPE, Record, Abbrev);
1927   Record.clear();
1928 }
1929 
1930 void ModuleBitcodeWriter::writeDITemplateValueParameter(
1931     const DITemplateValueParameter *N, SmallVectorImpl<uint64_t> &Record,
1932     unsigned Abbrev) {
1933   Record.push_back(N->isDistinct());
1934   Record.push_back(N->getTag());
1935   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1936   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1937   Record.push_back(N->isDefault());
1938   Record.push_back(VE.getMetadataOrNullID(N->getValue()));
1939 
1940   Stream.EmitRecord(bitc::METADATA_TEMPLATE_VALUE, Record, Abbrev);
1941   Record.clear();
1942 }
1943 
1944 void ModuleBitcodeWriter::writeDIGlobalVariable(
1945     const DIGlobalVariable *N, SmallVectorImpl<uint64_t> &Record,
1946     unsigned Abbrev) {
1947   const uint64_t Version = 2 << 1;
1948   Record.push_back((uint64_t)N->isDistinct() | Version);
1949   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1950   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1951   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1952   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1953   Record.push_back(N->getLine());
1954   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1955   Record.push_back(N->isLocalToUnit());
1956   Record.push_back(N->isDefinition());
1957   Record.push_back(VE.getMetadataOrNullID(N->getStaticDataMemberDeclaration()));
1958   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams()));
1959   Record.push_back(N->getAlignInBits());
1960 
1961   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR, Record, Abbrev);
1962   Record.clear();
1963 }
1964 
1965 void ModuleBitcodeWriter::writeDILocalVariable(
1966     const DILocalVariable *N, SmallVectorImpl<uint64_t> &Record,
1967     unsigned Abbrev) {
1968   // In order to support all possible bitcode formats in BitcodeReader we need
1969   // to distinguish the following cases:
1970   // 1) Record has no artificial tag (Record[1]),
1971   //   has no obsolete inlinedAt field (Record[9]).
1972   //   In this case Record size will be 8, HasAlignment flag is false.
1973   // 2) Record has artificial tag (Record[1]),
1974   //   has no obsolete inlignedAt field (Record[9]).
1975   //   In this case Record size will be 9, HasAlignment flag is false.
1976   // 3) Record has both artificial tag (Record[1]) and
1977   //   obsolete inlignedAt field (Record[9]).
1978   //   In this case Record size will be 10, HasAlignment flag is false.
1979   // 4) Record has neither artificial tag, nor inlignedAt field, but
1980   //   HasAlignment flag is true and Record[8] contains alignment value.
1981   const uint64_t HasAlignmentFlag = 1 << 1;
1982   Record.push_back((uint64_t)N->isDistinct() | HasAlignmentFlag);
1983   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1984   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1985   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1986   Record.push_back(N->getLine());
1987   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1988   Record.push_back(N->getArg());
1989   Record.push_back(N->getFlags());
1990   Record.push_back(N->getAlignInBits());
1991 
1992   Stream.EmitRecord(bitc::METADATA_LOCAL_VAR, Record, Abbrev);
1993   Record.clear();
1994 }
1995 
1996 void ModuleBitcodeWriter::writeDILabel(
1997     const DILabel *N, SmallVectorImpl<uint64_t> &Record,
1998     unsigned Abbrev) {
1999   Record.push_back((uint64_t)N->isDistinct());
2000   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2001   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2002   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2003   Record.push_back(N->getLine());
2004 
2005   Stream.EmitRecord(bitc::METADATA_LABEL, Record, Abbrev);
2006   Record.clear();
2007 }
2008 
2009 void ModuleBitcodeWriter::writeDIExpression(const DIExpression *N,
2010                                             SmallVectorImpl<uint64_t> &Record,
2011                                             unsigned Abbrev) {
2012   Record.reserve(N->getElements().size() + 1);
2013   const uint64_t Version = 3 << 1;
2014   Record.push_back((uint64_t)N->isDistinct() | Version);
2015   Record.append(N->elements_begin(), N->elements_end());
2016 
2017   Stream.EmitRecord(bitc::METADATA_EXPRESSION, Record, Abbrev);
2018   Record.clear();
2019 }
2020 
2021 void ModuleBitcodeWriter::writeDIGlobalVariableExpression(
2022     const DIGlobalVariableExpression *N, SmallVectorImpl<uint64_t> &Record,
2023     unsigned Abbrev) {
2024   Record.push_back(N->isDistinct());
2025   Record.push_back(VE.getMetadataOrNullID(N->getVariable()));
2026   Record.push_back(VE.getMetadataOrNullID(N->getExpression()));
2027 
2028   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR_EXPR, Record, Abbrev);
2029   Record.clear();
2030 }
2031 
2032 void ModuleBitcodeWriter::writeDIObjCProperty(const DIObjCProperty *N,
2033                                               SmallVectorImpl<uint64_t> &Record,
2034                                               unsigned Abbrev) {
2035   Record.push_back(N->isDistinct());
2036   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2037   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2038   Record.push_back(N->getLine());
2039   Record.push_back(VE.getMetadataOrNullID(N->getRawSetterName()));
2040   Record.push_back(VE.getMetadataOrNullID(N->getRawGetterName()));
2041   Record.push_back(N->getAttributes());
2042   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2043 
2044   Stream.EmitRecord(bitc::METADATA_OBJC_PROPERTY, Record, Abbrev);
2045   Record.clear();
2046 }
2047 
2048 void ModuleBitcodeWriter::writeDIImportedEntity(
2049     const DIImportedEntity *N, SmallVectorImpl<uint64_t> &Record,
2050     unsigned Abbrev) {
2051   Record.push_back(N->isDistinct());
2052   Record.push_back(N->getTag());
2053   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2054   Record.push_back(VE.getMetadataOrNullID(N->getEntity()));
2055   Record.push_back(N->getLine());
2056   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2057   Record.push_back(VE.getMetadataOrNullID(N->getRawFile()));
2058 
2059   Stream.EmitRecord(bitc::METADATA_IMPORTED_ENTITY, Record, Abbrev);
2060   Record.clear();
2061 }
2062 
2063 unsigned ModuleBitcodeWriter::createNamedMetadataAbbrev() {
2064   auto Abbv = std::make_shared<BitCodeAbbrev>();
2065   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
2066   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2067   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2068   return Stream.EmitAbbrev(std::move(Abbv));
2069 }
2070 
2071 void ModuleBitcodeWriter::writeNamedMetadata(
2072     SmallVectorImpl<uint64_t> &Record) {
2073   if (M.named_metadata_empty())
2074     return;
2075 
2076   unsigned Abbrev = createNamedMetadataAbbrev();
2077   for (const NamedMDNode &NMD : M.named_metadata()) {
2078     // Write name.
2079     StringRef Str = NMD.getName();
2080     Record.append(Str.bytes_begin(), Str.bytes_end());
2081     Stream.EmitRecord(bitc::METADATA_NAME, Record, Abbrev);
2082     Record.clear();
2083 
2084     // Write named metadata operands.
2085     for (const MDNode *N : NMD.operands())
2086       Record.push_back(VE.getMetadataID(N));
2087     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
2088     Record.clear();
2089   }
2090 }
2091 
2092 unsigned ModuleBitcodeWriter::createMetadataStringsAbbrev() {
2093   auto Abbv = std::make_shared<BitCodeAbbrev>();
2094   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRINGS));
2095   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // # of strings
2096   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // offset to chars
2097   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
2098   return Stream.EmitAbbrev(std::move(Abbv));
2099 }
2100 
2101 /// Write out a record for MDString.
2102 ///
2103 /// All the metadata strings in a metadata block are emitted in a single
2104 /// record.  The sizes and strings themselves are shoved into a blob.
2105 void ModuleBitcodeWriter::writeMetadataStrings(
2106     ArrayRef<const Metadata *> Strings, SmallVectorImpl<uint64_t> &Record) {
2107   if (Strings.empty())
2108     return;
2109 
2110   // Start the record with the number of strings.
2111   Record.push_back(bitc::METADATA_STRINGS);
2112   Record.push_back(Strings.size());
2113 
2114   // Emit the sizes of the strings in the blob.
2115   SmallString<256> Blob;
2116   {
2117     BitstreamWriter W(Blob);
2118     for (const Metadata *MD : Strings)
2119       W.EmitVBR(cast<MDString>(MD)->getLength(), 6);
2120     W.FlushToWord();
2121   }
2122 
2123   // Add the offset to the strings to the record.
2124   Record.push_back(Blob.size());
2125 
2126   // Add the strings to the blob.
2127   for (const Metadata *MD : Strings)
2128     Blob.append(cast<MDString>(MD)->getString());
2129 
2130   // Emit the final record.
2131   Stream.EmitRecordWithBlob(createMetadataStringsAbbrev(), Record, Blob);
2132   Record.clear();
2133 }
2134 
2135 // Generates an enum to use as an index in the Abbrev array of Metadata record.
2136 enum MetadataAbbrev : unsigned {
2137 #define HANDLE_MDNODE_LEAF(CLASS) CLASS##AbbrevID,
2138 #include "llvm/IR/Metadata.def"
2139   LastPlusOne
2140 };
2141 
2142 void ModuleBitcodeWriter::writeMetadataRecords(
2143     ArrayRef<const Metadata *> MDs, SmallVectorImpl<uint64_t> &Record,
2144     std::vector<unsigned> *MDAbbrevs, std::vector<uint64_t> *IndexPos) {
2145   if (MDs.empty())
2146     return;
2147 
2148   // Initialize MDNode abbreviations.
2149 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
2150 #include "llvm/IR/Metadata.def"
2151 
2152   for (const Metadata *MD : MDs) {
2153     if (IndexPos)
2154       IndexPos->push_back(Stream.GetCurrentBitNo());
2155     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
2156       assert(N->isResolved() && "Expected forward references to be resolved");
2157 
2158       switch (N->getMetadataID()) {
2159       default:
2160         llvm_unreachable("Invalid MDNode subclass");
2161 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
2162   case Metadata::CLASS##Kind:                                                  \
2163     if (MDAbbrevs)                                                             \
2164       write##CLASS(cast<CLASS>(N), Record,                                     \
2165                    (*MDAbbrevs)[MetadataAbbrev::CLASS##AbbrevID]);             \
2166     else                                                                       \
2167       write##CLASS(cast<CLASS>(N), Record, CLASS##Abbrev);                     \
2168     continue;
2169 #include "llvm/IR/Metadata.def"
2170       }
2171     }
2172     writeValueAsMetadata(cast<ValueAsMetadata>(MD), Record);
2173   }
2174 }
2175 
2176 void ModuleBitcodeWriter::writeModuleMetadata() {
2177   if (!VE.hasMDs() && M.named_metadata_empty())
2178     return;
2179 
2180   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 4);
2181   SmallVector<uint64_t, 64> Record;
2182 
2183   // Emit all abbrevs upfront, so that the reader can jump in the middle of the
2184   // block and load any metadata.
2185   std::vector<unsigned> MDAbbrevs;
2186 
2187   MDAbbrevs.resize(MetadataAbbrev::LastPlusOne);
2188   MDAbbrevs[MetadataAbbrev::DILocationAbbrevID] = createDILocationAbbrev();
2189   MDAbbrevs[MetadataAbbrev::GenericDINodeAbbrevID] =
2190       createGenericDINodeAbbrev();
2191 
2192   auto Abbv = std::make_shared<BitCodeAbbrev>();
2193   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX_OFFSET));
2194   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2195   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2196   unsigned OffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2197 
2198   Abbv = std::make_shared<BitCodeAbbrev>();
2199   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX));
2200   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2201   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2202   unsigned IndexAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2203 
2204   // Emit MDStrings together upfront.
2205   writeMetadataStrings(VE.getMDStrings(), Record);
2206 
2207   // We only emit an index for the metadata record if we have more than a given
2208   // (naive) threshold of metadatas, otherwise it is not worth it.
2209   if (VE.getNonMDStrings().size() > IndexThreshold) {
2210     // Write a placeholder value in for the offset of the metadata index,
2211     // which is written after the records, so that it can include
2212     // the offset of each entry. The placeholder offset will be
2213     // updated after all records are emitted.
2214     uint64_t Vals[] = {0, 0};
2215     Stream.EmitRecord(bitc::METADATA_INDEX_OFFSET, Vals, OffsetAbbrev);
2216   }
2217 
2218   // Compute and save the bit offset to the current position, which will be
2219   // patched when we emit the index later. We can simply subtract the 64-bit
2220   // fixed size from the current bit number to get the location to backpatch.
2221   uint64_t IndexOffsetRecordBitPos = Stream.GetCurrentBitNo();
2222 
2223   // This index will contain the bitpos for each individual record.
2224   std::vector<uint64_t> IndexPos;
2225   IndexPos.reserve(VE.getNonMDStrings().size());
2226 
2227   // Write all the records
2228   writeMetadataRecords(VE.getNonMDStrings(), Record, &MDAbbrevs, &IndexPos);
2229 
2230   if (VE.getNonMDStrings().size() > IndexThreshold) {
2231     // Now that we have emitted all the records we will emit the index. But
2232     // first
2233     // backpatch the forward reference so that the reader can skip the records
2234     // efficiently.
2235     Stream.BackpatchWord64(IndexOffsetRecordBitPos - 64,
2236                            Stream.GetCurrentBitNo() - IndexOffsetRecordBitPos);
2237 
2238     // Delta encode the index.
2239     uint64_t PreviousValue = IndexOffsetRecordBitPos;
2240     for (auto &Elt : IndexPos) {
2241       auto EltDelta = Elt - PreviousValue;
2242       PreviousValue = Elt;
2243       Elt = EltDelta;
2244     }
2245     // Emit the index record.
2246     Stream.EmitRecord(bitc::METADATA_INDEX, IndexPos, IndexAbbrev);
2247     IndexPos.clear();
2248   }
2249 
2250   // Write the named metadata now.
2251   writeNamedMetadata(Record);
2252 
2253   auto AddDeclAttachedMetadata = [&](const GlobalObject &GO) {
2254     SmallVector<uint64_t, 4> Record;
2255     Record.push_back(VE.getValueID(&GO));
2256     pushGlobalMetadataAttachment(Record, GO);
2257     Stream.EmitRecord(bitc::METADATA_GLOBAL_DECL_ATTACHMENT, Record);
2258   };
2259   for (const Function &F : M)
2260     if (F.isDeclaration() && F.hasMetadata())
2261       AddDeclAttachedMetadata(F);
2262   // FIXME: Only store metadata for declarations here, and move data for global
2263   // variable definitions to a separate block (PR28134).
2264   for (const GlobalVariable &GV : M.globals())
2265     if (GV.hasMetadata())
2266       AddDeclAttachedMetadata(GV);
2267 
2268   Stream.ExitBlock();
2269 }
2270 
2271 void ModuleBitcodeWriter::writeFunctionMetadata(const Function &F) {
2272   if (!VE.hasMDs())
2273     return;
2274 
2275   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
2276   SmallVector<uint64_t, 64> Record;
2277   writeMetadataStrings(VE.getMDStrings(), Record);
2278   writeMetadataRecords(VE.getNonMDStrings(), Record);
2279   Stream.ExitBlock();
2280 }
2281 
2282 void ModuleBitcodeWriter::pushGlobalMetadataAttachment(
2283     SmallVectorImpl<uint64_t> &Record, const GlobalObject &GO) {
2284   // [n x [id, mdnode]]
2285   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2286   GO.getAllMetadata(MDs);
2287   for (const auto &I : MDs) {
2288     Record.push_back(I.first);
2289     Record.push_back(VE.getMetadataID(I.second));
2290   }
2291 }
2292 
2293 void ModuleBitcodeWriter::writeFunctionMetadataAttachment(const Function &F) {
2294   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
2295 
2296   SmallVector<uint64_t, 64> Record;
2297 
2298   if (F.hasMetadata()) {
2299     pushGlobalMetadataAttachment(Record, F);
2300     Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2301     Record.clear();
2302   }
2303 
2304   // Write metadata attachments
2305   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
2306   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2307   for (const BasicBlock &BB : F)
2308     for (const Instruction &I : BB) {
2309       MDs.clear();
2310       I.getAllMetadataOtherThanDebugLoc(MDs);
2311 
2312       // If no metadata, ignore instruction.
2313       if (MDs.empty()) continue;
2314 
2315       Record.push_back(VE.getInstructionID(&I));
2316 
2317       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
2318         Record.push_back(MDs[i].first);
2319         Record.push_back(VE.getMetadataID(MDs[i].second));
2320       }
2321       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2322       Record.clear();
2323     }
2324 
2325   Stream.ExitBlock();
2326 }
2327 
2328 void ModuleBitcodeWriter::writeModuleMetadataKinds() {
2329   SmallVector<uint64_t, 64> Record;
2330 
2331   // Write metadata kinds
2332   // METADATA_KIND - [n x [id, name]]
2333   SmallVector<StringRef, 8> Names;
2334   M.getMDKindNames(Names);
2335 
2336   if (Names.empty()) return;
2337 
2338   Stream.EnterSubblock(bitc::METADATA_KIND_BLOCK_ID, 3);
2339 
2340   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
2341     Record.push_back(MDKindID);
2342     StringRef KName = Names[MDKindID];
2343     Record.append(KName.begin(), KName.end());
2344 
2345     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
2346     Record.clear();
2347   }
2348 
2349   Stream.ExitBlock();
2350 }
2351 
2352 void ModuleBitcodeWriter::writeOperandBundleTags() {
2353   // Write metadata kinds
2354   //
2355   // OPERAND_BUNDLE_TAGS_BLOCK_ID : N x OPERAND_BUNDLE_TAG
2356   //
2357   // OPERAND_BUNDLE_TAG - [strchr x N]
2358 
2359   SmallVector<StringRef, 8> Tags;
2360   M.getOperandBundleTags(Tags);
2361 
2362   if (Tags.empty())
2363     return;
2364 
2365   Stream.EnterSubblock(bitc::OPERAND_BUNDLE_TAGS_BLOCK_ID, 3);
2366 
2367   SmallVector<uint64_t, 64> Record;
2368 
2369   for (auto Tag : Tags) {
2370     Record.append(Tag.begin(), Tag.end());
2371 
2372     Stream.EmitRecord(bitc::OPERAND_BUNDLE_TAG, Record, 0);
2373     Record.clear();
2374   }
2375 
2376   Stream.ExitBlock();
2377 }
2378 
2379 void ModuleBitcodeWriter::writeSyncScopeNames() {
2380   SmallVector<StringRef, 8> SSNs;
2381   M.getContext().getSyncScopeNames(SSNs);
2382   if (SSNs.empty())
2383     return;
2384 
2385   Stream.EnterSubblock(bitc::SYNC_SCOPE_NAMES_BLOCK_ID, 2);
2386 
2387   SmallVector<uint64_t, 64> Record;
2388   for (auto SSN : SSNs) {
2389     Record.append(SSN.begin(), SSN.end());
2390     Stream.EmitRecord(bitc::SYNC_SCOPE_NAME, Record, 0);
2391     Record.clear();
2392   }
2393 
2394   Stream.ExitBlock();
2395 }
2396 
2397 void ModuleBitcodeWriter::writeConstants(unsigned FirstVal, unsigned LastVal,
2398                                          bool isGlobal) {
2399   if (FirstVal == LastVal) return;
2400 
2401   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
2402 
2403   unsigned AggregateAbbrev = 0;
2404   unsigned String8Abbrev = 0;
2405   unsigned CString7Abbrev = 0;
2406   unsigned CString6Abbrev = 0;
2407   // If this is a constant pool for the module, emit module-specific abbrevs.
2408   if (isGlobal) {
2409     // Abbrev for CST_CODE_AGGREGATE.
2410     auto Abbv = std::make_shared<BitCodeAbbrev>();
2411     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
2412     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2413     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
2414     AggregateAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2415 
2416     // Abbrev for CST_CODE_STRING.
2417     Abbv = std::make_shared<BitCodeAbbrev>();
2418     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
2419     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2420     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2421     String8Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2422     // Abbrev for CST_CODE_CSTRING.
2423     Abbv = std::make_shared<BitCodeAbbrev>();
2424     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2425     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2426     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2427     CString7Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2428     // Abbrev for CST_CODE_CSTRING.
2429     Abbv = std::make_shared<BitCodeAbbrev>();
2430     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2431     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2432     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2433     CString6Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2434   }
2435 
2436   SmallVector<uint64_t, 64> Record;
2437 
2438   const ValueEnumerator::ValueList &Vals = VE.getValues();
2439   Type *LastTy = nullptr;
2440   for (unsigned i = FirstVal; i != LastVal; ++i) {
2441     const Value *V = Vals[i].first;
2442     // If we need to switch types, do so now.
2443     if (V->getType() != LastTy) {
2444       LastTy = V->getType();
2445       Record.push_back(VE.getTypeID(LastTy));
2446       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
2447                         CONSTANTS_SETTYPE_ABBREV);
2448       Record.clear();
2449     }
2450 
2451     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
2452       Record.push_back(
2453           unsigned(IA->hasSideEffects()) | unsigned(IA->isAlignStack()) << 1 |
2454           unsigned(IA->getDialect() & 1) << 2 | unsigned(IA->canThrow()) << 3);
2455 
2456       // Add the asm string.
2457       const std::string &AsmStr = IA->getAsmString();
2458       Record.push_back(AsmStr.size());
2459       Record.append(AsmStr.begin(), AsmStr.end());
2460 
2461       // Add the constraint string.
2462       const std::string &ConstraintStr = IA->getConstraintString();
2463       Record.push_back(ConstraintStr.size());
2464       Record.append(ConstraintStr.begin(), ConstraintStr.end());
2465       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
2466       Record.clear();
2467       continue;
2468     }
2469     const Constant *C = cast<Constant>(V);
2470     unsigned Code = -1U;
2471     unsigned AbbrevToUse = 0;
2472     if (C->isNullValue()) {
2473       Code = bitc::CST_CODE_NULL;
2474     } else if (isa<PoisonValue>(C)) {
2475       Code = bitc::CST_CODE_POISON;
2476     } else if (isa<UndefValue>(C)) {
2477       Code = bitc::CST_CODE_UNDEF;
2478     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
2479       if (IV->getBitWidth() <= 64) {
2480         uint64_t V = IV->getSExtValue();
2481         emitSignedInt64(Record, V);
2482         Code = bitc::CST_CODE_INTEGER;
2483         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
2484       } else {                             // Wide integers, > 64 bits in size.
2485         emitWideAPInt(Record, IV->getValue());
2486         Code = bitc::CST_CODE_WIDE_INTEGER;
2487       }
2488     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
2489       Code = bitc::CST_CODE_FLOAT;
2490       Type *Ty = CFP->getType();
2491       if (Ty->isHalfTy() || Ty->isBFloatTy() || Ty->isFloatTy() ||
2492           Ty->isDoubleTy()) {
2493         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
2494       } else if (Ty->isX86_FP80Ty()) {
2495         // api needed to prevent premature destruction
2496         // bits are not in the same order as a normal i80 APInt, compensate.
2497         APInt api = CFP->getValueAPF().bitcastToAPInt();
2498         const uint64_t *p = api.getRawData();
2499         Record.push_back((p[1] << 48) | (p[0] >> 16));
2500         Record.push_back(p[0] & 0xffffLL);
2501       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
2502         APInt api = CFP->getValueAPF().bitcastToAPInt();
2503         const uint64_t *p = api.getRawData();
2504         Record.push_back(p[0]);
2505         Record.push_back(p[1]);
2506       } else {
2507         assert(0 && "Unknown FP type!");
2508       }
2509     } else if (isa<ConstantDataSequential>(C) &&
2510                cast<ConstantDataSequential>(C)->isString()) {
2511       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
2512       // Emit constant strings specially.
2513       unsigned NumElts = Str->getNumElements();
2514       // If this is a null-terminated string, use the denser CSTRING encoding.
2515       if (Str->isCString()) {
2516         Code = bitc::CST_CODE_CSTRING;
2517         --NumElts;  // Don't encode the null, which isn't allowed by char6.
2518       } else {
2519         Code = bitc::CST_CODE_STRING;
2520         AbbrevToUse = String8Abbrev;
2521       }
2522       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
2523       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
2524       for (unsigned i = 0; i != NumElts; ++i) {
2525         unsigned char V = Str->getElementAsInteger(i);
2526         Record.push_back(V);
2527         isCStr7 &= (V & 128) == 0;
2528         if (isCStrChar6)
2529           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
2530       }
2531 
2532       if (isCStrChar6)
2533         AbbrevToUse = CString6Abbrev;
2534       else if (isCStr7)
2535         AbbrevToUse = CString7Abbrev;
2536     } else if (const ConstantDataSequential *CDS =
2537                   dyn_cast<ConstantDataSequential>(C)) {
2538       Code = bitc::CST_CODE_DATA;
2539       Type *EltTy = CDS->getElementType();
2540       if (isa<IntegerType>(EltTy)) {
2541         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2542           Record.push_back(CDS->getElementAsInteger(i));
2543       } else {
2544         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2545           Record.push_back(
2546               CDS->getElementAsAPFloat(i).bitcastToAPInt().getLimitedValue());
2547       }
2548     } else if (isa<ConstantAggregate>(C)) {
2549       Code = bitc::CST_CODE_AGGREGATE;
2550       for (const Value *Op : C->operands())
2551         Record.push_back(VE.getValueID(Op));
2552       AbbrevToUse = AggregateAbbrev;
2553     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
2554       switch (CE->getOpcode()) {
2555       default:
2556         if (Instruction::isCast(CE->getOpcode())) {
2557           Code = bitc::CST_CODE_CE_CAST;
2558           Record.push_back(getEncodedCastOpcode(CE->getOpcode()));
2559           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2560           Record.push_back(VE.getValueID(C->getOperand(0)));
2561           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
2562         } else {
2563           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
2564           Code = bitc::CST_CODE_CE_BINOP;
2565           Record.push_back(getEncodedBinaryOpcode(CE->getOpcode()));
2566           Record.push_back(VE.getValueID(C->getOperand(0)));
2567           Record.push_back(VE.getValueID(C->getOperand(1)));
2568           uint64_t Flags = getOptimizationFlags(CE);
2569           if (Flags != 0)
2570             Record.push_back(Flags);
2571         }
2572         break;
2573       case Instruction::FNeg: {
2574         assert(CE->getNumOperands() == 1 && "Unknown constant expr!");
2575         Code = bitc::CST_CODE_CE_UNOP;
2576         Record.push_back(getEncodedUnaryOpcode(CE->getOpcode()));
2577         Record.push_back(VE.getValueID(C->getOperand(0)));
2578         uint64_t Flags = getOptimizationFlags(CE);
2579         if (Flags != 0)
2580           Record.push_back(Flags);
2581         break;
2582       }
2583       case Instruction::GetElementPtr: {
2584         Code = bitc::CST_CODE_CE_GEP;
2585         const auto *GO = cast<GEPOperator>(C);
2586         Record.push_back(VE.getTypeID(GO->getSourceElementType()));
2587         if (Optional<unsigned> Idx = GO->getInRangeIndex()) {
2588           Code = bitc::CST_CODE_CE_GEP_WITH_INRANGE_INDEX;
2589           Record.push_back((*Idx << 1) | GO->isInBounds());
2590         } else if (GO->isInBounds())
2591           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
2592         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
2593           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
2594           Record.push_back(VE.getValueID(C->getOperand(i)));
2595         }
2596         break;
2597       }
2598       case Instruction::Select:
2599         Code = bitc::CST_CODE_CE_SELECT;
2600         Record.push_back(VE.getValueID(C->getOperand(0)));
2601         Record.push_back(VE.getValueID(C->getOperand(1)));
2602         Record.push_back(VE.getValueID(C->getOperand(2)));
2603         break;
2604       case Instruction::ExtractElement:
2605         Code = bitc::CST_CODE_CE_EXTRACTELT;
2606         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2607         Record.push_back(VE.getValueID(C->getOperand(0)));
2608         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
2609         Record.push_back(VE.getValueID(C->getOperand(1)));
2610         break;
2611       case Instruction::InsertElement:
2612         Code = bitc::CST_CODE_CE_INSERTELT;
2613         Record.push_back(VE.getValueID(C->getOperand(0)));
2614         Record.push_back(VE.getValueID(C->getOperand(1)));
2615         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
2616         Record.push_back(VE.getValueID(C->getOperand(2)));
2617         break;
2618       case Instruction::ShuffleVector:
2619         // If the return type and argument types are the same, this is a
2620         // standard shufflevector instruction.  If the types are different,
2621         // then the shuffle is widening or truncating the input vectors, and
2622         // the argument type must also be encoded.
2623         if (C->getType() == C->getOperand(0)->getType()) {
2624           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
2625         } else {
2626           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
2627           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2628         }
2629         Record.push_back(VE.getValueID(C->getOperand(0)));
2630         Record.push_back(VE.getValueID(C->getOperand(1)));
2631         Record.push_back(VE.getValueID(CE->getShuffleMaskForBitcode()));
2632         break;
2633       case Instruction::ICmp:
2634       case Instruction::FCmp:
2635         Code = bitc::CST_CODE_CE_CMP;
2636         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2637         Record.push_back(VE.getValueID(C->getOperand(0)));
2638         Record.push_back(VE.getValueID(C->getOperand(1)));
2639         Record.push_back(CE->getPredicate());
2640         break;
2641       }
2642     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
2643       Code = bitc::CST_CODE_BLOCKADDRESS;
2644       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
2645       Record.push_back(VE.getValueID(BA->getFunction()));
2646       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
2647     } else if (const auto *Equiv = dyn_cast<DSOLocalEquivalent>(C)) {
2648       Code = bitc::CST_CODE_DSO_LOCAL_EQUIVALENT;
2649       Record.push_back(VE.getTypeID(Equiv->getGlobalValue()->getType()));
2650       Record.push_back(VE.getValueID(Equiv->getGlobalValue()));
2651     } else {
2652 #ifndef NDEBUG
2653       C->dump();
2654 #endif
2655       llvm_unreachable("Unknown constant!");
2656     }
2657     Stream.EmitRecord(Code, Record, AbbrevToUse);
2658     Record.clear();
2659   }
2660 
2661   Stream.ExitBlock();
2662 }
2663 
2664 void ModuleBitcodeWriter::writeModuleConstants() {
2665   const ValueEnumerator::ValueList &Vals = VE.getValues();
2666 
2667   // Find the first constant to emit, which is the first non-globalvalue value.
2668   // We know globalvalues have been emitted by WriteModuleInfo.
2669   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
2670     if (!isa<GlobalValue>(Vals[i].first)) {
2671       writeConstants(i, Vals.size(), true);
2672       return;
2673     }
2674   }
2675 }
2676 
2677 /// pushValueAndType - The file has to encode both the value and type id for
2678 /// many values, because we need to know what type to create for forward
2679 /// references.  However, most operands are not forward references, so this type
2680 /// field is not needed.
2681 ///
2682 /// This function adds V's value ID to Vals.  If the value ID is higher than the
2683 /// instruction ID, then it is a forward reference, and it also includes the
2684 /// type ID.  The value ID that is written is encoded relative to the InstID.
2685 bool ModuleBitcodeWriter::pushValueAndType(const Value *V, unsigned InstID,
2686                                            SmallVectorImpl<unsigned> &Vals) {
2687   unsigned ValID = VE.getValueID(V);
2688   // Make encoding relative to the InstID.
2689   Vals.push_back(InstID - ValID);
2690   if (ValID >= InstID) {
2691     Vals.push_back(VE.getTypeID(V->getType()));
2692     return true;
2693   }
2694   return false;
2695 }
2696 
2697 void ModuleBitcodeWriter::writeOperandBundles(const CallBase &CS,
2698                                               unsigned InstID) {
2699   SmallVector<unsigned, 64> Record;
2700   LLVMContext &C = CS.getContext();
2701 
2702   for (unsigned i = 0, e = CS.getNumOperandBundles(); i != e; ++i) {
2703     const auto &Bundle = CS.getOperandBundleAt(i);
2704     Record.push_back(C.getOperandBundleTagID(Bundle.getTagName()));
2705 
2706     for (auto &Input : Bundle.Inputs)
2707       pushValueAndType(Input, InstID, Record);
2708 
2709     Stream.EmitRecord(bitc::FUNC_CODE_OPERAND_BUNDLE, Record);
2710     Record.clear();
2711   }
2712 }
2713 
2714 /// pushValue - Like pushValueAndType, but where the type of the value is
2715 /// omitted (perhaps it was already encoded in an earlier operand).
2716 void ModuleBitcodeWriter::pushValue(const Value *V, unsigned InstID,
2717                                     SmallVectorImpl<unsigned> &Vals) {
2718   unsigned ValID = VE.getValueID(V);
2719   Vals.push_back(InstID - ValID);
2720 }
2721 
2722 void ModuleBitcodeWriter::pushValueSigned(const Value *V, unsigned InstID,
2723                                           SmallVectorImpl<uint64_t> &Vals) {
2724   unsigned ValID = VE.getValueID(V);
2725   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
2726   emitSignedInt64(Vals, diff);
2727 }
2728 
2729 /// WriteInstruction - Emit an instruction to the specified stream.
2730 void ModuleBitcodeWriter::writeInstruction(const Instruction &I,
2731                                            unsigned InstID,
2732                                            SmallVectorImpl<unsigned> &Vals) {
2733   unsigned Code = 0;
2734   unsigned AbbrevToUse = 0;
2735   VE.setInstructionID(&I);
2736   switch (I.getOpcode()) {
2737   default:
2738     if (Instruction::isCast(I.getOpcode())) {
2739       Code = bitc::FUNC_CODE_INST_CAST;
2740       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2741         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
2742       Vals.push_back(VE.getTypeID(I.getType()));
2743       Vals.push_back(getEncodedCastOpcode(I.getOpcode()));
2744     } else {
2745       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
2746       Code = bitc::FUNC_CODE_INST_BINOP;
2747       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2748         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
2749       pushValue(I.getOperand(1), InstID, Vals);
2750       Vals.push_back(getEncodedBinaryOpcode(I.getOpcode()));
2751       uint64_t Flags = getOptimizationFlags(&I);
2752       if (Flags != 0) {
2753         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
2754           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
2755         Vals.push_back(Flags);
2756       }
2757     }
2758     break;
2759   case Instruction::FNeg: {
2760     Code = bitc::FUNC_CODE_INST_UNOP;
2761     if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2762       AbbrevToUse = FUNCTION_INST_UNOP_ABBREV;
2763     Vals.push_back(getEncodedUnaryOpcode(I.getOpcode()));
2764     uint64_t Flags = getOptimizationFlags(&I);
2765     if (Flags != 0) {
2766       if (AbbrevToUse == FUNCTION_INST_UNOP_ABBREV)
2767         AbbrevToUse = FUNCTION_INST_UNOP_FLAGS_ABBREV;
2768       Vals.push_back(Flags);
2769     }
2770     break;
2771   }
2772   case Instruction::GetElementPtr: {
2773     Code = bitc::FUNC_CODE_INST_GEP;
2774     AbbrevToUse = FUNCTION_INST_GEP_ABBREV;
2775     auto &GEPInst = cast<GetElementPtrInst>(I);
2776     Vals.push_back(GEPInst.isInBounds());
2777     Vals.push_back(VE.getTypeID(GEPInst.getSourceElementType()));
2778     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
2779       pushValueAndType(I.getOperand(i), InstID, Vals);
2780     break;
2781   }
2782   case Instruction::ExtractValue: {
2783     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
2784     pushValueAndType(I.getOperand(0), InstID, Vals);
2785     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
2786     Vals.append(EVI->idx_begin(), EVI->idx_end());
2787     break;
2788   }
2789   case Instruction::InsertValue: {
2790     Code = bitc::FUNC_CODE_INST_INSERTVAL;
2791     pushValueAndType(I.getOperand(0), InstID, Vals);
2792     pushValueAndType(I.getOperand(1), InstID, Vals);
2793     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
2794     Vals.append(IVI->idx_begin(), IVI->idx_end());
2795     break;
2796   }
2797   case Instruction::Select: {
2798     Code = bitc::FUNC_CODE_INST_VSELECT;
2799     pushValueAndType(I.getOperand(1), InstID, Vals);
2800     pushValue(I.getOperand(2), InstID, Vals);
2801     pushValueAndType(I.getOperand(0), InstID, Vals);
2802     uint64_t Flags = getOptimizationFlags(&I);
2803     if (Flags != 0)
2804       Vals.push_back(Flags);
2805     break;
2806   }
2807   case Instruction::ExtractElement:
2808     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
2809     pushValueAndType(I.getOperand(0), InstID, Vals);
2810     pushValueAndType(I.getOperand(1), InstID, Vals);
2811     break;
2812   case Instruction::InsertElement:
2813     Code = bitc::FUNC_CODE_INST_INSERTELT;
2814     pushValueAndType(I.getOperand(0), InstID, Vals);
2815     pushValue(I.getOperand(1), InstID, Vals);
2816     pushValueAndType(I.getOperand(2), InstID, Vals);
2817     break;
2818   case Instruction::ShuffleVector:
2819     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
2820     pushValueAndType(I.getOperand(0), InstID, Vals);
2821     pushValue(I.getOperand(1), InstID, Vals);
2822     pushValue(cast<ShuffleVectorInst>(I).getShuffleMaskForBitcode(), InstID,
2823               Vals);
2824     break;
2825   case Instruction::ICmp:
2826   case Instruction::FCmp: {
2827     // compare returning Int1Ty or vector of Int1Ty
2828     Code = bitc::FUNC_CODE_INST_CMP2;
2829     pushValueAndType(I.getOperand(0), InstID, Vals);
2830     pushValue(I.getOperand(1), InstID, Vals);
2831     Vals.push_back(cast<CmpInst>(I).getPredicate());
2832     uint64_t Flags = getOptimizationFlags(&I);
2833     if (Flags != 0)
2834       Vals.push_back(Flags);
2835     break;
2836   }
2837 
2838   case Instruction::Ret:
2839     {
2840       Code = bitc::FUNC_CODE_INST_RET;
2841       unsigned NumOperands = I.getNumOperands();
2842       if (NumOperands == 0)
2843         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
2844       else if (NumOperands == 1) {
2845         if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2846           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
2847       } else {
2848         for (unsigned i = 0, e = NumOperands; i != e; ++i)
2849           pushValueAndType(I.getOperand(i), InstID, Vals);
2850       }
2851     }
2852     break;
2853   case Instruction::Br:
2854     {
2855       Code = bitc::FUNC_CODE_INST_BR;
2856       const BranchInst &II = cast<BranchInst>(I);
2857       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
2858       if (II.isConditional()) {
2859         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
2860         pushValue(II.getCondition(), InstID, Vals);
2861       }
2862     }
2863     break;
2864   case Instruction::Switch:
2865     {
2866       Code = bitc::FUNC_CODE_INST_SWITCH;
2867       const SwitchInst &SI = cast<SwitchInst>(I);
2868       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
2869       pushValue(SI.getCondition(), InstID, Vals);
2870       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
2871       for (auto Case : SI.cases()) {
2872         Vals.push_back(VE.getValueID(Case.getCaseValue()));
2873         Vals.push_back(VE.getValueID(Case.getCaseSuccessor()));
2874       }
2875     }
2876     break;
2877   case Instruction::IndirectBr:
2878     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
2879     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2880     // Encode the address operand as relative, but not the basic blocks.
2881     pushValue(I.getOperand(0), InstID, Vals);
2882     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
2883       Vals.push_back(VE.getValueID(I.getOperand(i)));
2884     break;
2885 
2886   case Instruction::Invoke: {
2887     const InvokeInst *II = cast<InvokeInst>(&I);
2888     const Value *Callee = II->getCalledOperand();
2889     FunctionType *FTy = II->getFunctionType();
2890 
2891     if (II->hasOperandBundles())
2892       writeOperandBundles(*II, InstID);
2893 
2894     Code = bitc::FUNC_CODE_INST_INVOKE;
2895 
2896     Vals.push_back(VE.getAttributeListID(II->getAttributes()));
2897     Vals.push_back(II->getCallingConv() | 1 << 13);
2898     Vals.push_back(VE.getValueID(II->getNormalDest()));
2899     Vals.push_back(VE.getValueID(II->getUnwindDest()));
2900     Vals.push_back(VE.getTypeID(FTy));
2901     pushValueAndType(Callee, InstID, Vals);
2902 
2903     // Emit value #'s for the fixed parameters.
2904     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
2905       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
2906 
2907     // Emit type/value pairs for varargs params.
2908     if (FTy->isVarArg()) {
2909       for (unsigned i = FTy->getNumParams(), e = II->getNumArgOperands();
2910            i != e; ++i)
2911         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
2912     }
2913     break;
2914   }
2915   case Instruction::Resume:
2916     Code = bitc::FUNC_CODE_INST_RESUME;
2917     pushValueAndType(I.getOperand(0), InstID, Vals);
2918     break;
2919   case Instruction::CleanupRet: {
2920     Code = bitc::FUNC_CODE_INST_CLEANUPRET;
2921     const auto &CRI = cast<CleanupReturnInst>(I);
2922     pushValue(CRI.getCleanupPad(), InstID, Vals);
2923     if (CRI.hasUnwindDest())
2924       Vals.push_back(VE.getValueID(CRI.getUnwindDest()));
2925     break;
2926   }
2927   case Instruction::CatchRet: {
2928     Code = bitc::FUNC_CODE_INST_CATCHRET;
2929     const auto &CRI = cast<CatchReturnInst>(I);
2930     pushValue(CRI.getCatchPad(), InstID, Vals);
2931     Vals.push_back(VE.getValueID(CRI.getSuccessor()));
2932     break;
2933   }
2934   case Instruction::CleanupPad:
2935   case Instruction::CatchPad: {
2936     const auto &FuncletPad = cast<FuncletPadInst>(I);
2937     Code = isa<CatchPadInst>(FuncletPad) ? bitc::FUNC_CODE_INST_CATCHPAD
2938                                          : bitc::FUNC_CODE_INST_CLEANUPPAD;
2939     pushValue(FuncletPad.getParentPad(), InstID, Vals);
2940 
2941     unsigned NumArgOperands = FuncletPad.getNumArgOperands();
2942     Vals.push_back(NumArgOperands);
2943     for (unsigned Op = 0; Op != NumArgOperands; ++Op)
2944       pushValueAndType(FuncletPad.getArgOperand(Op), InstID, Vals);
2945     break;
2946   }
2947   case Instruction::CatchSwitch: {
2948     Code = bitc::FUNC_CODE_INST_CATCHSWITCH;
2949     const auto &CatchSwitch = cast<CatchSwitchInst>(I);
2950 
2951     pushValue(CatchSwitch.getParentPad(), InstID, Vals);
2952 
2953     unsigned NumHandlers = CatchSwitch.getNumHandlers();
2954     Vals.push_back(NumHandlers);
2955     for (const BasicBlock *CatchPadBB : CatchSwitch.handlers())
2956       Vals.push_back(VE.getValueID(CatchPadBB));
2957 
2958     if (CatchSwitch.hasUnwindDest())
2959       Vals.push_back(VE.getValueID(CatchSwitch.getUnwindDest()));
2960     break;
2961   }
2962   case Instruction::CallBr: {
2963     const CallBrInst *CBI = cast<CallBrInst>(&I);
2964     const Value *Callee = CBI->getCalledOperand();
2965     FunctionType *FTy = CBI->getFunctionType();
2966 
2967     if (CBI->hasOperandBundles())
2968       writeOperandBundles(*CBI, InstID);
2969 
2970     Code = bitc::FUNC_CODE_INST_CALLBR;
2971 
2972     Vals.push_back(VE.getAttributeListID(CBI->getAttributes()));
2973 
2974     Vals.push_back(CBI->getCallingConv() << bitc::CALL_CCONV |
2975                    1 << bitc::CALL_EXPLICIT_TYPE);
2976 
2977     Vals.push_back(VE.getValueID(CBI->getDefaultDest()));
2978     Vals.push_back(CBI->getNumIndirectDests());
2979     for (unsigned i = 0, e = CBI->getNumIndirectDests(); i != e; ++i)
2980       Vals.push_back(VE.getValueID(CBI->getIndirectDest(i)));
2981 
2982     Vals.push_back(VE.getTypeID(FTy));
2983     pushValueAndType(Callee, InstID, Vals);
2984 
2985     // Emit value #'s for the fixed parameters.
2986     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
2987       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
2988 
2989     // Emit type/value pairs for varargs params.
2990     if (FTy->isVarArg()) {
2991       for (unsigned i = FTy->getNumParams(), e = CBI->getNumArgOperands();
2992            i != e; ++i)
2993         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
2994     }
2995     break;
2996   }
2997   case Instruction::Unreachable:
2998     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
2999     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
3000     break;
3001 
3002   case Instruction::PHI: {
3003     const PHINode &PN = cast<PHINode>(I);
3004     Code = bitc::FUNC_CODE_INST_PHI;
3005     // With the newer instruction encoding, forward references could give
3006     // negative valued IDs.  This is most common for PHIs, so we use
3007     // signed VBRs.
3008     SmallVector<uint64_t, 128> Vals64;
3009     Vals64.push_back(VE.getTypeID(PN.getType()));
3010     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
3011       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64);
3012       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
3013     }
3014 
3015     uint64_t Flags = getOptimizationFlags(&I);
3016     if (Flags != 0)
3017       Vals64.push_back(Flags);
3018 
3019     // Emit a Vals64 vector and exit.
3020     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
3021     Vals64.clear();
3022     return;
3023   }
3024 
3025   case Instruction::LandingPad: {
3026     const LandingPadInst &LP = cast<LandingPadInst>(I);
3027     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
3028     Vals.push_back(VE.getTypeID(LP.getType()));
3029     Vals.push_back(LP.isCleanup());
3030     Vals.push_back(LP.getNumClauses());
3031     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
3032       if (LP.isCatch(I))
3033         Vals.push_back(LandingPadInst::Catch);
3034       else
3035         Vals.push_back(LandingPadInst::Filter);
3036       pushValueAndType(LP.getClause(I), InstID, Vals);
3037     }
3038     break;
3039   }
3040 
3041   case Instruction::Alloca: {
3042     Code = bitc::FUNC_CODE_INST_ALLOCA;
3043     const AllocaInst &AI = cast<AllocaInst>(I);
3044     Vals.push_back(VE.getTypeID(AI.getAllocatedType()));
3045     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
3046     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
3047     using APV = AllocaPackedValues;
3048     unsigned Record = 0;
3049     Bitfield::set<APV::Align>(Record, getEncodedAlign(AI.getAlign()));
3050     Bitfield::set<APV::UsedWithInAlloca>(Record, AI.isUsedWithInAlloca());
3051     Bitfield::set<APV::ExplicitType>(Record, true);
3052     Bitfield::set<APV::SwiftError>(Record, AI.isSwiftError());
3053     Vals.push_back(Record);
3054     break;
3055   }
3056 
3057   case Instruction::Load:
3058     if (cast<LoadInst>(I).isAtomic()) {
3059       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
3060       pushValueAndType(I.getOperand(0), InstID, Vals);
3061     } else {
3062       Code = bitc::FUNC_CODE_INST_LOAD;
3063       if (!pushValueAndType(I.getOperand(0), InstID, Vals)) // ptr
3064         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
3065     }
3066     Vals.push_back(VE.getTypeID(I.getType()));
3067     Vals.push_back(getEncodedAlign(cast<LoadInst>(I).getAlign()));
3068     Vals.push_back(cast<LoadInst>(I).isVolatile());
3069     if (cast<LoadInst>(I).isAtomic()) {
3070       Vals.push_back(getEncodedOrdering(cast<LoadInst>(I).getOrdering()));
3071       Vals.push_back(getEncodedSyncScopeID(cast<LoadInst>(I).getSyncScopeID()));
3072     }
3073     break;
3074   case Instruction::Store:
3075     if (cast<StoreInst>(I).isAtomic())
3076       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
3077     else
3078       Code = bitc::FUNC_CODE_INST_STORE;
3079     pushValueAndType(I.getOperand(1), InstID, Vals); // ptrty + ptr
3080     pushValueAndType(I.getOperand(0), InstID, Vals); // valty + val
3081     Vals.push_back(getEncodedAlign(cast<StoreInst>(I).getAlign()));
3082     Vals.push_back(cast<StoreInst>(I).isVolatile());
3083     if (cast<StoreInst>(I).isAtomic()) {
3084       Vals.push_back(getEncodedOrdering(cast<StoreInst>(I).getOrdering()));
3085       Vals.push_back(
3086           getEncodedSyncScopeID(cast<StoreInst>(I).getSyncScopeID()));
3087     }
3088     break;
3089   case Instruction::AtomicCmpXchg:
3090     Code = bitc::FUNC_CODE_INST_CMPXCHG;
3091     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
3092     pushValueAndType(I.getOperand(1), InstID, Vals); // cmp.
3093     pushValue(I.getOperand(2), InstID, Vals);        // newval.
3094     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
3095     Vals.push_back(
3096         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
3097     Vals.push_back(
3098         getEncodedSyncScopeID(cast<AtomicCmpXchgInst>(I).getSyncScopeID()));
3099     Vals.push_back(
3100         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
3101     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
3102     Vals.push_back(getEncodedAlign(cast<AtomicCmpXchgInst>(I).getAlign()));
3103     break;
3104   case Instruction::AtomicRMW:
3105     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
3106     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
3107     pushValueAndType(I.getOperand(1), InstID, Vals); // valty + val
3108     Vals.push_back(
3109         getEncodedRMWOperation(cast<AtomicRMWInst>(I).getOperation()));
3110     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
3111     Vals.push_back(getEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
3112     Vals.push_back(
3113         getEncodedSyncScopeID(cast<AtomicRMWInst>(I).getSyncScopeID()));
3114     Vals.push_back(getEncodedAlign(cast<AtomicRMWInst>(I).getAlign()));
3115     break;
3116   case Instruction::Fence:
3117     Code = bitc::FUNC_CODE_INST_FENCE;
3118     Vals.push_back(getEncodedOrdering(cast<FenceInst>(I).getOrdering()));
3119     Vals.push_back(getEncodedSyncScopeID(cast<FenceInst>(I).getSyncScopeID()));
3120     break;
3121   case Instruction::Call: {
3122     const CallInst &CI = cast<CallInst>(I);
3123     FunctionType *FTy = CI.getFunctionType();
3124 
3125     if (CI.hasOperandBundles())
3126       writeOperandBundles(CI, InstID);
3127 
3128     Code = bitc::FUNC_CODE_INST_CALL;
3129 
3130     Vals.push_back(VE.getAttributeListID(CI.getAttributes()));
3131 
3132     unsigned Flags = getOptimizationFlags(&I);
3133     Vals.push_back(CI.getCallingConv() << bitc::CALL_CCONV |
3134                    unsigned(CI.isTailCall()) << bitc::CALL_TAIL |
3135                    unsigned(CI.isMustTailCall()) << bitc::CALL_MUSTTAIL |
3136                    1 << bitc::CALL_EXPLICIT_TYPE |
3137                    unsigned(CI.isNoTailCall()) << bitc::CALL_NOTAIL |
3138                    unsigned(Flags != 0) << bitc::CALL_FMF);
3139     if (Flags != 0)
3140       Vals.push_back(Flags);
3141 
3142     Vals.push_back(VE.getTypeID(FTy));
3143     pushValueAndType(CI.getCalledOperand(), InstID, Vals); // Callee
3144 
3145     // Emit value #'s for the fixed parameters.
3146     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
3147       // Check for labels (can happen with asm labels).
3148       if (FTy->getParamType(i)->isLabelTy())
3149         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
3150       else
3151         pushValue(CI.getArgOperand(i), InstID, Vals); // fixed param.
3152     }
3153 
3154     // Emit type/value pairs for varargs params.
3155     if (FTy->isVarArg()) {
3156       for (unsigned i = FTy->getNumParams(), e = CI.getNumArgOperands();
3157            i != e; ++i)
3158         pushValueAndType(CI.getArgOperand(i), InstID, Vals); // varargs
3159     }
3160     break;
3161   }
3162   case Instruction::VAArg:
3163     Code = bitc::FUNC_CODE_INST_VAARG;
3164     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
3165     pushValue(I.getOperand(0), InstID, Vals);                   // valist.
3166     Vals.push_back(VE.getTypeID(I.getType())); // restype.
3167     break;
3168   case Instruction::Freeze:
3169     Code = bitc::FUNC_CODE_INST_FREEZE;
3170     pushValueAndType(I.getOperand(0), InstID, Vals);
3171     break;
3172   }
3173 
3174   Stream.EmitRecord(Code, Vals, AbbrevToUse);
3175   Vals.clear();
3176 }
3177 
3178 /// Write a GlobalValue VST to the module. The purpose of this data structure is
3179 /// to allow clients to efficiently find the function body.
3180 void ModuleBitcodeWriter::writeGlobalValueSymbolTable(
3181   DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3182   // Get the offset of the VST we are writing, and backpatch it into
3183   // the VST forward declaration record.
3184   uint64_t VSTOffset = Stream.GetCurrentBitNo();
3185   // The BitcodeStartBit was the stream offset of the identification block.
3186   VSTOffset -= bitcodeStartBit();
3187   assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
3188   // Note that we add 1 here because the offset is relative to one word
3189   // before the start of the identification block, which was historically
3190   // always the start of the regular bitcode header.
3191   Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32 + 1);
3192 
3193   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3194 
3195   auto Abbv = std::make_shared<BitCodeAbbrev>();
3196   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
3197   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
3198   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
3199   unsigned FnEntryAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3200 
3201   for (const Function &F : M) {
3202     uint64_t Record[2];
3203 
3204     if (F.isDeclaration())
3205       continue;
3206 
3207     Record[0] = VE.getValueID(&F);
3208 
3209     // Save the word offset of the function (from the start of the
3210     // actual bitcode written to the stream).
3211     uint64_t BitcodeIndex = FunctionToBitcodeIndex[&F] - bitcodeStartBit();
3212     assert((BitcodeIndex & 31) == 0 && "function block not 32-bit aligned");
3213     // Note that we add 1 here because the offset is relative to one word
3214     // before the start of the identification block, which was historically
3215     // always the start of the regular bitcode header.
3216     Record[1] = BitcodeIndex / 32 + 1;
3217 
3218     Stream.EmitRecord(bitc::VST_CODE_FNENTRY, Record, FnEntryAbbrev);
3219   }
3220 
3221   Stream.ExitBlock();
3222 }
3223 
3224 /// Emit names for arguments, instructions and basic blocks in a function.
3225 void ModuleBitcodeWriter::writeFunctionLevelValueSymbolTable(
3226     const ValueSymbolTable &VST) {
3227   if (VST.empty())
3228     return;
3229 
3230   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3231 
3232   // FIXME: Set up the abbrev, we know how many values there are!
3233   // FIXME: We know if the type names can use 7-bit ascii.
3234   SmallVector<uint64_t, 64> NameVals;
3235 
3236   for (const ValueName &Name : VST) {
3237     // Figure out the encoding to use for the name.
3238     StringEncoding Bits = getStringEncoding(Name.getKey());
3239 
3240     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
3241     NameVals.push_back(VE.getValueID(Name.getValue()));
3242 
3243     // VST_CODE_ENTRY:   [valueid, namechar x N]
3244     // VST_CODE_BBENTRY: [bbid, namechar x N]
3245     unsigned Code;
3246     if (isa<BasicBlock>(Name.getValue())) {
3247       Code = bitc::VST_CODE_BBENTRY;
3248       if (Bits == SE_Char6)
3249         AbbrevToUse = VST_BBENTRY_6_ABBREV;
3250     } else {
3251       Code = bitc::VST_CODE_ENTRY;
3252       if (Bits == SE_Char6)
3253         AbbrevToUse = VST_ENTRY_6_ABBREV;
3254       else if (Bits == SE_Fixed7)
3255         AbbrevToUse = VST_ENTRY_7_ABBREV;
3256     }
3257 
3258     for (const auto P : Name.getKey())
3259       NameVals.push_back((unsigned char)P);
3260 
3261     // Emit the finished record.
3262     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
3263     NameVals.clear();
3264   }
3265 
3266   Stream.ExitBlock();
3267 }
3268 
3269 void ModuleBitcodeWriter::writeUseList(UseListOrder &&Order) {
3270   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
3271   unsigned Code;
3272   if (isa<BasicBlock>(Order.V))
3273     Code = bitc::USELIST_CODE_BB;
3274   else
3275     Code = bitc::USELIST_CODE_DEFAULT;
3276 
3277   SmallVector<uint64_t, 64> Record(Order.Shuffle.begin(), Order.Shuffle.end());
3278   Record.push_back(VE.getValueID(Order.V));
3279   Stream.EmitRecord(Code, Record);
3280 }
3281 
3282 void ModuleBitcodeWriter::writeUseListBlock(const Function *F) {
3283   assert(VE.shouldPreserveUseListOrder() &&
3284          "Expected to be preserving use-list order");
3285 
3286   auto hasMore = [&]() {
3287     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
3288   };
3289   if (!hasMore())
3290     // Nothing to do.
3291     return;
3292 
3293   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
3294   while (hasMore()) {
3295     writeUseList(std::move(VE.UseListOrders.back()));
3296     VE.UseListOrders.pop_back();
3297   }
3298   Stream.ExitBlock();
3299 }
3300 
3301 /// Emit a function body to the module stream.
3302 void ModuleBitcodeWriter::writeFunction(
3303     const Function &F,
3304     DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3305   // Save the bitcode index of the start of this function block for recording
3306   // in the VST.
3307   FunctionToBitcodeIndex[&F] = Stream.GetCurrentBitNo();
3308 
3309   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
3310   VE.incorporateFunction(F);
3311 
3312   SmallVector<unsigned, 64> Vals;
3313 
3314   // Emit the number of basic blocks, so the reader can create them ahead of
3315   // time.
3316   Vals.push_back(VE.getBasicBlocks().size());
3317   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
3318   Vals.clear();
3319 
3320   // If there are function-local constants, emit them now.
3321   unsigned CstStart, CstEnd;
3322   VE.getFunctionConstantRange(CstStart, CstEnd);
3323   writeConstants(CstStart, CstEnd, false);
3324 
3325   // If there is function-local metadata, emit it now.
3326   writeFunctionMetadata(F);
3327 
3328   // Keep a running idea of what the instruction ID is.
3329   unsigned InstID = CstEnd;
3330 
3331   bool NeedsMetadataAttachment = F.hasMetadata();
3332 
3333   DILocation *LastDL = nullptr;
3334   // Finally, emit all the instructions, in order.
3335   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
3336     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
3337          I != E; ++I) {
3338       writeInstruction(*I, InstID, Vals);
3339 
3340       if (!I->getType()->isVoidTy())
3341         ++InstID;
3342 
3343       // If the instruction has metadata, write a metadata attachment later.
3344       NeedsMetadataAttachment |= I->hasMetadataOtherThanDebugLoc();
3345 
3346       // If the instruction has a debug location, emit it.
3347       DILocation *DL = I->getDebugLoc();
3348       if (!DL)
3349         continue;
3350 
3351       if (DL == LastDL) {
3352         // Just repeat the same debug loc as last time.
3353         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
3354         continue;
3355       }
3356 
3357       Vals.push_back(DL->getLine());
3358       Vals.push_back(DL->getColumn());
3359       Vals.push_back(VE.getMetadataOrNullID(DL->getScope()));
3360       Vals.push_back(VE.getMetadataOrNullID(DL->getInlinedAt()));
3361       Vals.push_back(DL->isImplicitCode());
3362       Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
3363       Vals.clear();
3364 
3365       LastDL = DL;
3366     }
3367 
3368   // Emit names for all the instructions etc.
3369   if (auto *Symtab = F.getValueSymbolTable())
3370     writeFunctionLevelValueSymbolTable(*Symtab);
3371 
3372   if (NeedsMetadataAttachment)
3373     writeFunctionMetadataAttachment(F);
3374   if (VE.shouldPreserveUseListOrder())
3375     writeUseListBlock(&F);
3376   VE.purgeFunction();
3377   Stream.ExitBlock();
3378 }
3379 
3380 // Emit blockinfo, which defines the standard abbreviations etc.
3381 void ModuleBitcodeWriter::writeBlockInfo() {
3382   // We only want to emit block info records for blocks that have multiple
3383   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
3384   // Other blocks can define their abbrevs inline.
3385   Stream.EnterBlockInfoBlock();
3386 
3387   { // 8-bit fixed-width VST_CODE_ENTRY/VST_CODE_BBENTRY strings.
3388     auto Abbv = std::make_shared<BitCodeAbbrev>();
3389     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
3390     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3391     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3392     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3393     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3394         VST_ENTRY_8_ABBREV)
3395       llvm_unreachable("Unexpected abbrev ordering!");
3396   }
3397 
3398   { // 7-bit fixed width VST_CODE_ENTRY strings.
3399     auto Abbv = std::make_shared<BitCodeAbbrev>();
3400     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3401     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3402     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3403     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3404     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3405         VST_ENTRY_7_ABBREV)
3406       llvm_unreachable("Unexpected abbrev ordering!");
3407   }
3408   { // 6-bit char6 VST_CODE_ENTRY strings.
3409     auto Abbv = std::make_shared<BitCodeAbbrev>();
3410     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3411     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3412     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3413     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3414     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3415         VST_ENTRY_6_ABBREV)
3416       llvm_unreachable("Unexpected abbrev ordering!");
3417   }
3418   { // 6-bit char6 VST_CODE_BBENTRY strings.
3419     auto Abbv = std::make_shared<BitCodeAbbrev>();
3420     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
3421     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3422     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3423     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3424     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3425         VST_BBENTRY_6_ABBREV)
3426       llvm_unreachable("Unexpected abbrev ordering!");
3427   }
3428 
3429   { // SETTYPE abbrev for CONSTANTS_BLOCK.
3430     auto Abbv = std::make_shared<BitCodeAbbrev>();
3431     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
3432     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
3433                               VE.computeBitsRequiredForTypeIndicies()));
3434     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3435         CONSTANTS_SETTYPE_ABBREV)
3436       llvm_unreachable("Unexpected abbrev ordering!");
3437   }
3438 
3439   { // INTEGER abbrev for CONSTANTS_BLOCK.
3440     auto Abbv = std::make_shared<BitCodeAbbrev>();
3441     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
3442     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3443     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3444         CONSTANTS_INTEGER_ABBREV)
3445       llvm_unreachable("Unexpected abbrev ordering!");
3446   }
3447 
3448   { // CE_CAST abbrev for CONSTANTS_BLOCK.
3449     auto Abbv = std::make_shared<BitCodeAbbrev>();
3450     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
3451     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
3452     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
3453                               VE.computeBitsRequiredForTypeIndicies()));
3454     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
3455 
3456     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3457         CONSTANTS_CE_CAST_Abbrev)
3458       llvm_unreachable("Unexpected abbrev ordering!");
3459   }
3460   { // NULL abbrev for CONSTANTS_BLOCK.
3461     auto Abbv = std::make_shared<BitCodeAbbrev>();
3462     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
3463     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3464         CONSTANTS_NULL_Abbrev)
3465       llvm_unreachable("Unexpected abbrev ordering!");
3466   }
3467 
3468   // FIXME: This should only use space for first class types!
3469 
3470   { // INST_LOAD abbrev for FUNCTION_BLOCK.
3471     auto Abbv = std::make_shared<BitCodeAbbrev>();
3472     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
3473     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
3474     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
3475                               VE.computeBitsRequiredForTypeIndicies()));
3476     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
3477     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
3478     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3479         FUNCTION_INST_LOAD_ABBREV)
3480       llvm_unreachable("Unexpected abbrev ordering!");
3481   }
3482   { // INST_UNOP abbrev for FUNCTION_BLOCK.
3483     auto Abbv = std::make_shared<BitCodeAbbrev>();
3484     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3485     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3486     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3487     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3488         FUNCTION_INST_UNOP_ABBREV)
3489       llvm_unreachable("Unexpected abbrev ordering!");
3490   }
3491   { // INST_UNOP_FLAGS abbrev for FUNCTION_BLOCK.
3492     auto Abbv = std::make_shared<BitCodeAbbrev>();
3493     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3494     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3495     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3496     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3497     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3498         FUNCTION_INST_UNOP_FLAGS_ABBREV)
3499       llvm_unreachable("Unexpected abbrev ordering!");
3500   }
3501   { // INST_BINOP abbrev for FUNCTION_BLOCK.
3502     auto Abbv = std::make_shared<BitCodeAbbrev>();
3503     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3504     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3505     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3506     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3507     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3508         FUNCTION_INST_BINOP_ABBREV)
3509       llvm_unreachable("Unexpected abbrev ordering!");
3510   }
3511   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
3512     auto Abbv = std::make_shared<BitCodeAbbrev>();
3513     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3514     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3515     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3516     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3517     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3518     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3519         FUNCTION_INST_BINOP_FLAGS_ABBREV)
3520       llvm_unreachable("Unexpected abbrev ordering!");
3521   }
3522   { // INST_CAST abbrev for FUNCTION_BLOCK.
3523     auto Abbv = std::make_shared<BitCodeAbbrev>();
3524     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
3525     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
3526     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
3527                               VE.computeBitsRequiredForTypeIndicies()));
3528     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
3529     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3530         FUNCTION_INST_CAST_ABBREV)
3531       llvm_unreachable("Unexpected abbrev ordering!");
3532   }
3533 
3534   { // INST_RET abbrev for FUNCTION_BLOCK.
3535     auto Abbv = std::make_shared<BitCodeAbbrev>();
3536     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3537     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3538         FUNCTION_INST_RET_VOID_ABBREV)
3539       llvm_unreachable("Unexpected abbrev ordering!");
3540   }
3541   { // INST_RET abbrev for FUNCTION_BLOCK.
3542     auto Abbv = std::make_shared<BitCodeAbbrev>();
3543     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3544     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
3545     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3546         FUNCTION_INST_RET_VAL_ABBREV)
3547       llvm_unreachable("Unexpected abbrev ordering!");
3548   }
3549   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
3550     auto Abbv = std::make_shared<BitCodeAbbrev>();
3551     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
3552     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3553         FUNCTION_INST_UNREACHABLE_ABBREV)
3554       llvm_unreachable("Unexpected abbrev ordering!");
3555   }
3556   {
3557     auto Abbv = std::make_shared<BitCodeAbbrev>();
3558     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_GEP));
3559     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
3560     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, // dest ty
3561                               Log2_32_Ceil(VE.getTypes().size() + 1)));
3562     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3563     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
3564     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3565         FUNCTION_INST_GEP_ABBREV)
3566       llvm_unreachable("Unexpected abbrev ordering!");
3567   }
3568 
3569   Stream.ExitBlock();
3570 }
3571 
3572 /// Write the module path strings, currently only used when generating
3573 /// a combined index file.
3574 void IndexBitcodeWriter::writeModStrings() {
3575   Stream.EnterSubblock(bitc::MODULE_STRTAB_BLOCK_ID, 3);
3576 
3577   // TODO: See which abbrev sizes we actually need to emit
3578 
3579   // 8-bit fixed-width MST_ENTRY strings.
3580   auto Abbv = std::make_shared<BitCodeAbbrev>();
3581   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3582   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3583   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3584   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3585   unsigned Abbrev8Bit = Stream.EmitAbbrev(std::move(Abbv));
3586 
3587   // 7-bit fixed width MST_ENTRY strings.
3588   Abbv = std::make_shared<BitCodeAbbrev>();
3589   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3590   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3591   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3592   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3593   unsigned Abbrev7Bit = Stream.EmitAbbrev(std::move(Abbv));
3594 
3595   // 6-bit char6 MST_ENTRY strings.
3596   Abbv = std::make_shared<BitCodeAbbrev>();
3597   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3598   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3599   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3600   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3601   unsigned Abbrev6Bit = Stream.EmitAbbrev(std::move(Abbv));
3602 
3603   // Module Hash, 160 bits SHA1. Optionally, emitted after each MST_CODE_ENTRY.
3604   Abbv = std::make_shared<BitCodeAbbrev>();
3605   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_HASH));
3606   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3607   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3608   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3609   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3610   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3611   unsigned AbbrevHash = Stream.EmitAbbrev(std::move(Abbv));
3612 
3613   SmallVector<unsigned, 64> Vals;
3614   forEachModule(
3615       [&](const StringMapEntry<std::pair<uint64_t, ModuleHash>> &MPSE) {
3616         StringRef Key = MPSE.getKey();
3617         const auto &Value = MPSE.getValue();
3618         StringEncoding Bits = getStringEncoding(Key);
3619         unsigned AbbrevToUse = Abbrev8Bit;
3620         if (Bits == SE_Char6)
3621           AbbrevToUse = Abbrev6Bit;
3622         else if (Bits == SE_Fixed7)
3623           AbbrevToUse = Abbrev7Bit;
3624 
3625         Vals.push_back(Value.first);
3626         Vals.append(Key.begin(), Key.end());
3627 
3628         // Emit the finished record.
3629         Stream.EmitRecord(bitc::MST_CODE_ENTRY, Vals, AbbrevToUse);
3630 
3631         // Emit an optional hash for the module now
3632         const auto &Hash = Value.second;
3633         if (llvm::any_of(Hash, [](uint32_t H) { return H; })) {
3634           Vals.assign(Hash.begin(), Hash.end());
3635           // Emit the hash record.
3636           Stream.EmitRecord(bitc::MST_CODE_HASH, Vals, AbbrevHash);
3637         }
3638 
3639         Vals.clear();
3640       });
3641   Stream.ExitBlock();
3642 }
3643 
3644 /// Write the function type metadata related records that need to appear before
3645 /// a function summary entry (whether per-module or combined).
3646 template <typename Fn>
3647 static void writeFunctionTypeMetadataRecords(BitstreamWriter &Stream,
3648                                              FunctionSummary *FS,
3649                                              Fn GetValueID) {
3650   if (!FS->type_tests().empty())
3651     Stream.EmitRecord(bitc::FS_TYPE_TESTS, FS->type_tests());
3652 
3653   SmallVector<uint64_t, 64> Record;
3654 
3655   auto WriteVFuncIdVec = [&](uint64_t Ty,
3656                              ArrayRef<FunctionSummary::VFuncId> VFs) {
3657     if (VFs.empty())
3658       return;
3659     Record.clear();
3660     for (auto &VF : VFs) {
3661       Record.push_back(VF.GUID);
3662       Record.push_back(VF.Offset);
3663     }
3664     Stream.EmitRecord(Ty, Record);
3665   };
3666 
3667   WriteVFuncIdVec(bitc::FS_TYPE_TEST_ASSUME_VCALLS,
3668                   FS->type_test_assume_vcalls());
3669   WriteVFuncIdVec(bitc::FS_TYPE_CHECKED_LOAD_VCALLS,
3670                   FS->type_checked_load_vcalls());
3671 
3672   auto WriteConstVCallVec = [&](uint64_t Ty,
3673                                 ArrayRef<FunctionSummary::ConstVCall> VCs) {
3674     for (auto &VC : VCs) {
3675       Record.clear();
3676       Record.push_back(VC.VFunc.GUID);
3677       Record.push_back(VC.VFunc.Offset);
3678       llvm::append_range(Record, VC.Args);
3679       Stream.EmitRecord(Ty, Record);
3680     }
3681   };
3682 
3683   WriteConstVCallVec(bitc::FS_TYPE_TEST_ASSUME_CONST_VCALL,
3684                      FS->type_test_assume_const_vcalls());
3685   WriteConstVCallVec(bitc::FS_TYPE_CHECKED_LOAD_CONST_VCALL,
3686                      FS->type_checked_load_const_vcalls());
3687 
3688   auto WriteRange = [&](ConstantRange Range) {
3689     Range = Range.sextOrTrunc(FunctionSummary::ParamAccess::RangeWidth);
3690     assert(Range.getLower().getNumWords() == 1);
3691     assert(Range.getUpper().getNumWords() == 1);
3692     emitSignedInt64(Record, *Range.getLower().getRawData());
3693     emitSignedInt64(Record, *Range.getUpper().getRawData());
3694   };
3695 
3696   if (!FS->paramAccesses().empty()) {
3697     Record.clear();
3698     for (auto &Arg : FS->paramAccesses()) {
3699       size_t UndoSize = Record.size();
3700       Record.push_back(Arg.ParamNo);
3701       WriteRange(Arg.Use);
3702       Record.push_back(Arg.Calls.size());
3703       for (auto &Call : Arg.Calls) {
3704         Record.push_back(Call.ParamNo);
3705         Optional<unsigned> ValueID = GetValueID(Call.Callee);
3706         if (!ValueID) {
3707           // If ValueID is unknown we can't drop just this call, we must drop
3708           // entire parameter.
3709           Record.resize(UndoSize);
3710           break;
3711         }
3712         Record.push_back(*ValueID);
3713         WriteRange(Call.Offsets);
3714       }
3715     }
3716     if (!Record.empty())
3717       Stream.EmitRecord(bitc::FS_PARAM_ACCESS, Record);
3718   }
3719 }
3720 
3721 /// Collect type IDs from type tests used by function.
3722 static void
3723 getReferencedTypeIds(FunctionSummary *FS,
3724                      std::set<GlobalValue::GUID> &ReferencedTypeIds) {
3725   if (!FS->type_tests().empty())
3726     for (auto &TT : FS->type_tests())
3727       ReferencedTypeIds.insert(TT);
3728 
3729   auto GetReferencedTypesFromVFuncIdVec =
3730       [&](ArrayRef<FunctionSummary::VFuncId> VFs) {
3731         for (auto &VF : VFs)
3732           ReferencedTypeIds.insert(VF.GUID);
3733       };
3734 
3735   GetReferencedTypesFromVFuncIdVec(FS->type_test_assume_vcalls());
3736   GetReferencedTypesFromVFuncIdVec(FS->type_checked_load_vcalls());
3737 
3738   auto GetReferencedTypesFromConstVCallVec =
3739       [&](ArrayRef<FunctionSummary::ConstVCall> VCs) {
3740         for (auto &VC : VCs)
3741           ReferencedTypeIds.insert(VC.VFunc.GUID);
3742       };
3743 
3744   GetReferencedTypesFromConstVCallVec(FS->type_test_assume_const_vcalls());
3745   GetReferencedTypesFromConstVCallVec(FS->type_checked_load_const_vcalls());
3746 }
3747 
3748 static void writeWholeProgramDevirtResolutionByArg(
3749     SmallVector<uint64_t, 64> &NameVals, const std::vector<uint64_t> &args,
3750     const WholeProgramDevirtResolution::ByArg &ByArg) {
3751   NameVals.push_back(args.size());
3752   llvm::append_range(NameVals, args);
3753 
3754   NameVals.push_back(ByArg.TheKind);
3755   NameVals.push_back(ByArg.Info);
3756   NameVals.push_back(ByArg.Byte);
3757   NameVals.push_back(ByArg.Bit);
3758 }
3759 
3760 static void writeWholeProgramDevirtResolution(
3761     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3762     uint64_t Id, const WholeProgramDevirtResolution &Wpd) {
3763   NameVals.push_back(Id);
3764 
3765   NameVals.push_back(Wpd.TheKind);
3766   NameVals.push_back(StrtabBuilder.add(Wpd.SingleImplName));
3767   NameVals.push_back(Wpd.SingleImplName.size());
3768 
3769   NameVals.push_back(Wpd.ResByArg.size());
3770   for (auto &A : Wpd.ResByArg)
3771     writeWholeProgramDevirtResolutionByArg(NameVals, A.first, A.second);
3772 }
3773 
3774 static void writeTypeIdSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
3775                                      StringTableBuilder &StrtabBuilder,
3776                                      const std::string &Id,
3777                                      const TypeIdSummary &Summary) {
3778   NameVals.push_back(StrtabBuilder.add(Id));
3779   NameVals.push_back(Id.size());
3780 
3781   NameVals.push_back(Summary.TTRes.TheKind);
3782   NameVals.push_back(Summary.TTRes.SizeM1BitWidth);
3783   NameVals.push_back(Summary.TTRes.AlignLog2);
3784   NameVals.push_back(Summary.TTRes.SizeM1);
3785   NameVals.push_back(Summary.TTRes.BitMask);
3786   NameVals.push_back(Summary.TTRes.InlineBits);
3787 
3788   for (auto &W : Summary.WPDRes)
3789     writeWholeProgramDevirtResolution(NameVals, StrtabBuilder, W.first,
3790                                       W.second);
3791 }
3792 
3793 static void writeTypeIdCompatibleVtableSummaryRecord(
3794     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3795     const std::string &Id, const TypeIdCompatibleVtableInfo &Summary,
3796     ValueEnumerator &VE) {
3797   NameVals.push_back(StrtabBuilder.add(Id));
3798   NameVals.push_back(Id.size());
3799 
3800   for (auto &P : Summary) {
3801     NameVals.push_back(P.AddressPointOffset);
3802     NameVals.push_back(VE.getValueID(P.VTableVI.getValue()));
3803   }
3804 }
3805 
3806 // Helper to emit a single function summary record.
3807 void ModuleBitcodeWriterBase::writePerModuleFunctionSummaryRecord(
3808     SmallVector<uint64_t, 64> &NameVals, GlobalValueSummary *Summary,
3809     unsigned ValueID, unsigned FSCallsAbbrev, unsigned FSCallsProfileAbbrev,
3810     const Function &F) {
3811   NameVals.push_back(ValueID);
3812 
3813   FunctionSummary *FS = cast<FunctionSummary>(Summary);
3814 
3815   writeFunctionTypeMetadataRecords(
3816       Stream, FS, [&](const ValueInfo &VI) -> Optional<unsigned> {
3817         return {VE.getValueID(VI.getValue())};
3818       });
3819 
3820   auto SpecialRefCnts = FS->specialRefCounts();
3821   NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
3822   NameVals.push_back(FS->instCount());
3823   NameVals.push_back(getEncodedFFlags(FS->fflags()));
3824   NameVals.push_back(FS->refs().size());
3825   NameVals.push_back(SpecialRefCnts.first);  // rorefcnt
3826   NameVals.push_back(SpecialRefCnts.second); // worefcnt
3827 
3828   for (auto &RI : FS->refs())
3829     NameVals.push_back(VE.getValueID(RI.getValue()));
3830 
3831   bool HasProfileData =
3832       F.hasProfileData() || ForceSummaryEdgesCold != FunctionSummary::FSHT_None;
3833   for (auto &ECI : FS->calls()) {
3834     NameVals.push_back(getValueId(ECI.first));
3835     if (HasProfileData)
3836       NameVals.push_back(static_cast<uint8_t>(ECI.second.Hotness));
3837     else if (WriteRelBFToSummary)
3838       NameVals.push_back(ECI.second.RelBlockFreq);
3839   }
3840 
3841   unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
3842   unsigned Code =
3843       (HasProfileData ? bitc::FS_PERMODULE_PROFILE
3844                       : (WriteRelBFToSummary ? bitc::FS_PERMODULE_RELBF
3845                                              : bitc::FS_PERMODULE));
3846 
3847   // Emit the finished record.
3848   Stream.EmitRecord(Code, NameVals, FSAbbrev);
3849   NameVals.clear();
3850 }
3851 
3852 // Collect the global value references in the given variable's initializer,
3853 // and emit them in a summary record.
3854 void ModuleBitcodeWriterBase::writeModuleLevelReferences(
3855     const GlobalVariable &V, SmallVector<uint64_t, 64> &NameVals,
3856     unsigned FSModRefsAbbrev, unsigned FSModVTableRefsAbbrev) {
3857   auto VI = Index->getValueInfo(V.getGUID());
3858   if (!VI || VI.getSummaryList().empty()) {
3859     // Only declarations should not have a summary (a declaration might however
3860     // have a summary if the def was in module level asm).
3861     assert(V.isDeclaration());
3862     return;
3863   }
3864   auto *Summary = VI.getSummaryList()[0].get();
3865   NameVals.push_back(VE.getValueID(&V));
3866   GlobalVarSummary *VS = cast<GlobalVarSummary>(Summary);
3867   NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
3868   NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
3869 
3870   auto VTableFuncs = VS->vTableFuncs();
3871   if (!VTableFuncs.empty())
3872     NameVals.push_back(VS->refs().size());
3873 
3874   unsigned SizeBeforeRefs = NameVals.size();
3875   for (auto &RI : VS->refs())
3876     NameVals.push_back(VE.getValueID(RI.getValue()));
3877   // Sort the refs for determinism output, the vector returned by FS->refs() has
3878   // been initialized from a DenseSet.
3879   llvm::sort(drop_begin(NameVals, SizeBeforeRefs));
3880 
3881   if (VTableFuncs.empty())
3882     Stream.EmitRecord(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS, NameVals,
3883                       FSModRefsAbbrev);
3884   else {
3885     // VTableFuncs pairs should already be sorted by offset.
3886     for (auto &P : VTableFuncs) {
3887       NameVals.push_back(VE.getValueID(P.FuncVI.getValue()));
3888       NameVals.push_back(P.VTableOffset);
3889     }
3890 
3891     Stream.EmitRecord(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS, NameVals,
3892                       FSModVTableRefsAbbrev);
3893   }
3894   NameVals.clear();
3895 }
3896 
3897 /// Emit the per-module summary section alongside the rest of
3898 /// the module's bitcode.
3899 void ModuleBitcodeWriterBase::writePerModuleGlobalValueSummary() {
3900   // By default we compile with ThinLTO if the module has a summary, but the
3901   // client can request full LTO with a module flag.
3902   bool IsThinLTO = true;
3903   if (auto *MD =
3904           mdconst::extract_or_null<ConstantInt>(M.getModuleFlag("ThinLTO")))
3905     IsThinLTO = MD->getZExtValue();
3906   Stream.EnterSubblock(IsThinLTO ? bitc::GLOBALVAL_SUMMARY_BLOCK_ID
3907                                  : bitc::FULL_LTO_GLOBALVAL_SUMMARY_BLOCK_ID,
3908                        4);
3909 
3910   Stream.EmitRecord(
3911       bitc::FS_VERSION,
3912       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
3913 
3914   // Write the index flags.
3915   uint64_t Flags = 0;
3916   // Bits 1-3 are set only in the combined index, skip them.
3917   if (Index->enableSplitLTOUnit())
3918     Flags |= 0x8;
3919   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Flags});
3920 
3921   if (Index->begin() == Index->end()) {
3922     Stream.ExitBlock();
3923     return;
3924   }
3925 
3926   for (const auto &GVI : valueIds()) {
3927     Stream.EmitRecord(bitc::FS_VALUE_GUID,
3928                       ArrayRef<uint64_t>{GVI.second, GVI.first});
3929   }
3930 
3931   // Abbrev for FS_PERMODULE_PROFILE.
3932   auto Abbv = std::make_shared<BitCodeAbbrev>();
3933   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_PROFILE));
3934   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3935   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3936   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3937   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3938   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3939   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
3940   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
3941   // numrefs x valueid, n x (valueid, hotness)
3942   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3943   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3944   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3945 
3946   // Abbrev for FS_PERMODULE or FS_PERMODULE_RELBF.
3947   Abbv = std::make_shared<BitCodeAbbrev>();
3948   if (WriteRelBFToSummary)
3949     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_RELBF));
3950   else
3951     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE));
3952   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3953   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3954   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3955   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3956   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3957   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
3958   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
3959   // numrefs x valueid, n x (valueid [, rel_block_freq])
3960   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3961   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3962   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3963 
3964   // Abbrev for FS_PERMODULE_GLOBALVAR_INIT_REFS.
3965   Abbv = std::make_shared<BitCodeAbbrev>();
3966   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS));
3967   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
3968   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
3969   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));  // valueids
3970   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3971   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3972 
3973   // Abbrev for FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS.
3974   Abbv = std::make_shared<BitCodeAbbrev>();
3975   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS));
3976   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
3977   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
3978   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numrefs
3979   // numrefs x valueid, n x (valueid , offset)
3980   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3981   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3982   unsigned FSModVTableRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3983 
3984   // Abbrev for FS_ALIAS.
3985   Abbv = std::make_shared<BitCodeAbbrev>();
3986   Abbv->Add(BitCodeAbbrevOp(bitc::FS_ALIAS));
3987   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3988   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3989   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3990   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3991 
3992   // Abbrev for FS_TYPE_ID_METADATA
3993   Abbv = std::make_shared<BitCodeAbbrev>();
3994   Abbv->Add(BitCodeAbbrevOp(bitc::FS_TYPE_ID_METADATA));
3995   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid strtab index
3996   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid length
3997   // n x (valueid , offset)
3998   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3999   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4000   unsigned TypeIdCompatibleVtableAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4001 
4002   SmallVector<uint64_t, 64> NameVals;
4003   // Iterate over the list of functions instead of the Index to
4004   // ensure the ordering is stable.
4005   for (const Function &F : M) {
4006     // Summary emission does not support anonymous functions, they have to
4007     // renamed using the anonymous function renaming pass.
4008     if (!F.hasName())
4009       report_fatal_error("Unexpected anonymous function when writing summary");
4010 
4011     ValueInfo VI = Index->getValueInfo(F.getGUID());
4012     if (!VI || VI.getSummaryList().empty()) {
4013       // Only declarations should not have a summary (a declaration might
4014       // however have a summary if the def was in module level asm).
4015       assert(F.isDeclaration());
4016       continue;
4017     }
4018     auto *Summary = VI.getSummaryList()[0].get();
4019     writePerModuleFunctionSummaryRecord(NameVals, Summary, VE.getValueID(&F),
4020                                         FSCallsAbbrev, FSCallsProfileAbbrev, F);
4021   }
4022 
4023   // Capture references from GlobalVariable initializers, which are outside
4024   // of a function scope.
4025   for (const GlobalVariable &G : M.globals())
4026     writeModuleLevelReferences(G, NameVals, FSModRefsAbbrev,
4027                                FSModVTableRefsAbbrev);
4028 
4029   for (const GlobalAlias &A : M.aliases()) {
4030     auto *Aliasee = A.getBaseObject();
4031     if (!Aliasee->hasName())
4032       // Nameless function don't have an entry in the summary, skip it.
4033       continue;
4034     auto AliasId = VE.getValueID(&A);
4035     auto AliaseeId = VE.getValueID(Aliasee);
4036     NameVals.push_back(AliasId);
4037     auto *Summary = Index->getGlobalValueSummary(A);
4038     AliasSummary *AS = cast<AliasSummary>(Summary);
4039     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
4040     NameVals.push_back(AliaseeId);
4041     Stream.EmitRecord(bitc::FS_ALIAS, NameVals, FSAliasAbbrev);
4042     NameVals.clear();
4043   }
4044 
4045   for (auto &S : Index->typeIdCompatibleVtableMap()) {
4046     writeTypeIdCompatibleVtableSummaryRecord(NameVals, StrtabBuilder, S.first,
4047                                              S.second, VE);
4048     Stream.EmitRecord(bitc::FS_TYPE_ID_METADATA, NameVals,
4049                       TypeIdCompatibleVtableAbbrev);
4050     NameVals.clear();
4051   }
4052 
4053   Stream.EmitRecord(bitc::FS_BLOCK_COUNT,
4054                     ArrayRef<uint64_t>{Index->getBlockCount()});
4055 
4056   Stream.ExitBlock();
4057 }
4058 
4059 /// Emit the combined summary section into the combined index file.
4060 void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
4061   Stream.EnterSubblock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID, 3);
4062   Stream.EmitRecord(
4063       bitc::FS_VERSION,
4064       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
4065 
4066   // Write the index flags.
4067   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Index.getFlags()});
4068 
4069   for (const auto &GVI : valueIds()) {
4070     Stream.EmitRecord(bitc::FS_VALUE_GUID,
4071                       ArrayRef<uint64_t>{GVI.second, GVI.first});
4072   }
4073 
4074   // Abbrev for FS_COMBINED.
4075   auto Abbv = std::make_shared<BitCodeAbbrev>();
4076   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED));
4077   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4078   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4079   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4080   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4081   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4082   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
4083   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4084   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4085   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4086   // numrefs x valueid, n x (valueid)
4087   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4088   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4089   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4090 
4091   // Abbrev for FS_COMBINED_PROFILE.
4092   Abbv = std::make_shared<BitCodeAbbrev>();
4093   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_PROFILE));
4094   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4095   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4096   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4097   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4098   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4099   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
4100   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4101   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4102   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4103   // numrefs x valueid, n x (valueid, hotness)
4104   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4105   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4106   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4107 
4108   // Abbrev for FS_COMBINED_GLOBALVAR_INIT_REFS.
4109   Abbv = std::make_shared<BitCodeAbbrev>();
4110   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS));
4111   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4112   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4113   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4114   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));    // valueids
4115   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4116   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4117 
4118   // Abbrev for FS_COMBINED_ALIAS.
4119   Abbv = std::make_shared<BitCodeAbbrev>();
4120   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_ALIAS));
4121   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4122   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4123   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4124   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4125   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4126 
4127   // The aliases are emitted as a post-pass, and will point to the value
4128   // id of the aliasee. Save them in a vector for post-processing.
4129   SmallVector<AliasSummary *, 64> Aliases;
4130 
4131   // Save the value id for each summary for alias emission.
4132   DenseMap<const GlobalValueSummary *, unsigned> SummaryToValueIdMap;
4133 
4134   SmallVector<uint64_t, 64> NameVals;
4135 
4136   // Set that will be populated during call to writeFunctionTypeMetadataRecords
4137   // with the type ids referenced by this index file.
4138   std::set<GlobalValue::GUID> ReferencedTypeIds;
4139 
4140   // For local linkage, we also emit the original name separately
4141   // immediately after the record.
4142   auto MaybeEmitOriginalName = [&](GlobalValueSummary &S) {
4143     if (!GlobalValue::isLocalLinkage(S.linkage()))
4144       return;
4145     NameVals.push_back(S.getOriginalName());
4146     Stream.EmitRecord(bitc::FS_COMBINED_ORIGINAL_NAME, NameVals);
4147     NameVals.clear();
4148   };
4149 
4150   std::set<GlobalValue::GUID> DefOrUseGUIDs;
4151   forEachSummary([&](GVInfo I, bool IsAliasee) {
4152     GlobalValueSummary *S = I.second;
4153     assert(S);
4154     DefOrUseGUIDs.insert(I.first);
4155     for (const ValueInfo &VI : S->refs())
4156       DefOrUseGUIDs.insert(VI.getGUID());
4157 
4158     auto ValueId = getValueId(I.first);
4159     assert(ValueId);
4160     SummaryToValueIdMap[S] = *ValueId;
4161 
4162     // If this is invoked for an aliasee, we want to record the above
4163     // mapping, but then not emit a summary entry (if the aliasee is
4164     // to be imported, we will invoke this separately with IsAliasee=false).
4165     if (IsAliasee)
4166       return;
4167 
4168     if (auto *AS = dyn_cast<AliasSummary>(S)) {
4169       // Will process aliases as a post-pass because the reader wants all
4170       // global to be loaded first.
4171       Aliases.push_back(AS);
4172       return;
4173     }
4174 
4175     if (auto *VS = dyn_cast<GlobalVarSummary>(S)) {
4176       NameVals.push_back(*ValueId);
4177       NameVals.push_back(Index.getModuleId(VS->modulePath()));
4178       NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
4179       NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
4180       for (auto &RI : VS->refs()) {
4181         auto RefValueId = getValueId(RI.getGUID());
4182         if (!RefValueId)
4183           continue;
4184         NameVals.push_back(*RefValueId);
4185       }
4186 
4187       // Emit the finished record.
4188       Stream.EmitRecord(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS, NameVals,
4189                         FSModRefsAbbrev);
4190       NameVals.clear();
4191       MaybeEmitOriginalName(*S);
4192       return;
4193     }
4194 
4195     auto GetValueId = [&](const ValueInfo &VI) -> Optional<unsigned> {
4196       GlobalValue::GUID GUID = VI.getGUID();
4197       Optional<unsigned> CallValueId = getValueId(GUID);
4198       if (CallValueId)
4199         return CallValueId;
4200       // For SamplePGO, the indirect call targets for local functions will
4201       // have its original name annotated in profile. We try to find the
4202       // corresponding PGOFuncName as the GUID.
4203       GUID = Index.getGUIDFromOriginalID(GUID);
4204       if (!GUID)
4205         return None;
4206       CallValueId = getValueId(GUID);
4207       if (!CallValueId)
4208         return None;
4209       // The mapping from OriginalId to GUID may return a GUID
4210       // that corresponds to a static variable. Filter it out here.
4211       // This can happen when
4212       // 1) There is a call to a library function which does not have
4213       // a CallValidId;
4214       // 2) There is a static variable with the  OriginalGUID identical
4215       // to the GUID of the library function in 1);
4216       // When this happens, the logic for SamplePGO kicks in and
4217       // the static variable in 2) will be found, which needs to be
4218       // filtered out.
4219       auto *GVSum = Index.getGlobalValueSummary(GUID, false);
4220       if (GVSum && GVSum->getSummaryKind() == GlobalValueSummary::GlobalVarKind)
4221         return None;
4222       return CallValueId;
4223     };
4224 
4225     auto *FS = cast<FunctionSummary>(S);
4226     writeFunctionTypeMetadataRecords(Stream, FS, GetValueId);
4227     getReferencedTypeIds(FS, ReferencedTypeIds);
4228 
4229     NameVals.push_back(*ValueId);
4230     NameVals.push_back(Index.getModuleId(FS->modulePath()));
4231     NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
4232     NameVals.push_back(FS->instCount());
4233     NameVals.push_back(getEncodedFFlags(FS->fflags()));
4234     NameVals.push_back(FS->entryCount());
4235 
4236     // Fill in below
4237     NameVals.push_back(0); // numrefs
4238     NameVals.push_back(0); // rorefcnt
4239     NameVals.push_back(0); // worefcnt
4240 
4241     unsigned Count = 0, RORefCnt = 0, WORefCnt = 0;
4242     for (auto &RI : FS->refs()) {
4243       auto RefValueId = getValueId(RI.getGUID());
4244       if (!RefValueId)
4245         continue;
4246       NameVals.push_back(*RefValueId);
4247       if (RI.isReadOnly())
4248         RORefCnt++;
4249       else if (RI.isWriteOnly())
4250         WORefCnt++;
4251       Count++;
4252     }
4253     NameVals[6] = Count;
4254     NameVals[7] = RORefCnt;
4255     NameVals[8] = WORefCnt;
4256 
4257     bool HasProfileData = false;
4258     for (auto &EI : FS->calls()) {
4259       HasProfileData |=
4260           EI.second.getHotness() != CalleeInfo::HotnessType::Unknown;
4261       if (HasProfileData)
4262         break;
4263     }
4264 
4265     for (auto &EI : FS->calls()) {
4266       // If this GUID doesn't have a value id, it doesn't have a function
4267       // summary and we don't need to record any calls to it.
4268       Optional<unsigned> CallValueId = GetValueId(EI.first);
4269       if (!CallValueId)
4270         continue;
4271       NameVals.push_back(*CallValueId);
4272       if (HasProfileData)
4273         NameVals.push_back(static_cast<uint8_t>(EI.second.Hotness));
4274     }
4275 
4276     unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
4277     unsigned Code =
4278         (HasProfileData ? bitc::FS_COMBINED_PROFILE : bitc::FS_COMBINED);
4279 
4280     // Emit the finished record.
4281     Stream.EmitRecord(Code, NameVals, FSAbbrev);
4282     NameVals.clear();
4283     MaybeEmitOriginalName(*S);
4284   });
4285 
4286   for (auto *AS : Aliases) {
4287     auto AliasValueId = SummaryToValueIdMap[AS];
4288     assert(AliasValueId);
4289     NameVals.push_back(AliasValueId);
4290     NameVals.push_back(Index.getModuleId(AS->modulePath()));
4291     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
4292     auto AliaseeValueId = SummaryToValueIdMap[&AS->getAliasee()];
4293     assert(AliaseeValueId);
4294     NameVals.push_back(AliaseeValueId);
4295 
4296     // Emit the finished record.
4297     Stream.EmitRecord(bitc::FS_COMBINED_ALIAS, NameVals, FSAliasAbbrev);
4298     NameVals.clear();
4299     MaybeEmitOriginalName(*AS);
4300 
4301     if (auto *FS = dyn_cast<FunctionSummary>(&AS->getAliasee()))
4302       getReferencedTypeIds(FS, ReferencedTypeIds);
4303   }
4304 
4305   if (!Index.cfiFunctionDefs().empty()) {
4306     for (auto &S : Index.cfiFunctionDefs()) {
4307       if (DefOrUseGUIDs.count(
4308               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4309         NameVals.push_back(StrtabBuilder.add(S));
4310         NameVals.push_back(S.size());
4311       }
4312     }
4313     if (!NameVals.empty()) {
4314       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DEFS, NameVals);
4315       NameVals.clear();
4316     }
4317   }
4318 
4319   if (!Index.cfiFunctionDecls().empty()) {
4320     for (auto &S : Index.cfiFunctionDecls()) {
4321       if (DefOrUseGUIDs.count(
4322               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4323         NameVals.push_back(StrtabBuilder.add(S));
4324         NameVals.push_back(S.size());
4325       }
4326     }
4327     if (!NameVals.empty()) {
4328       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DECLS, NameVals);
4329       NameVals.clear();
4330     }
4331   }
4332 
4333   // Walk the GUIDs that were referenced, and write the
4334   // corresponding type id records.
4335   for (auto &T : ReferencedTypeIds) {
4336     auto TidIter = Index.typeIds().equal_range(T);
4337     for (auto It = TidIter.first; It != TidIter.second; ++It) {
4338       writeTypeIdSummaryRecord(NameVals, StrtabBuilder, It->second.first,
4339                                It->second.second);
4340       Stream.EmitRecord(bitc::FS_TYPE_ID, NameVals);
4341       NameVals.clear();
4342     }
4343   }
4344 
4345   Stream.EmitRecord(bitc::FS_BLOCK_COUNT,
4346                     ArrayRef<uint64_t>{Index.getBlockCount()});
4347 
4348   Stream.ExitBlock();
4349 }
4350 
4351 /// Create the "IDENTIFICATION_BLOCK_ID" containing a single string with the
4352 /// current llvm version, and a record for the epoch number.
4353 static void writeIdentificationBlock(BitstreamWriter &Stream) {
4354   Stream.EnterSubblock(bitc::IDENTIFICATION_BLOCK_ID, 5);
4355 
4356   // Write the "user readable" string identifying the bitcode producer
4357   auto Abbv = std::make_shared<BitCodeAbbrev>();
4358   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_STRING));
4359   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4360   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
4361   auto StringAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4362   writeStringRecord(Stream, bitc::IDENTIFICATION_CODE_STRING,
4363                     "LLVM" LLVM_VERSION_STRING, StringAbbrev);
4364 
4365   // Write the epoch version
4366   Abbv = std::make_shared<BitCodeAbbrev>();
4367   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_EPOCH));
4368   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
4369   auto EpochAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4370   constexpr std::array<unsigned, 1> Vals = {{bitc::BITCODE_CURRENT_EPOCH}};
4371   Stream.EmitRecord(bitc::IDENTIFICATION_CODE_EPOCH, Vals, EpochAbbrev);
4372   Stream.ExitBlock();
4373 }
4374 
4375 void ModuleBitcodeWriter::writeModuleHash(size_t BlockStartPos) {
4376   // Emit the module's hash.
4377   // MODULE_CODE_HASH: [5*i32]
4378   if (GenerateHash) {
4379     uint32_t Vals[5];
4380     Hasher.update(ArrayRef<uint8_t>((const uint8_t *)&(Buffer)[BlockStartPos],
4381                                     Buffer.size() - BlockStartPos));
4382     StringRef Hash = Hasher.result();
4383     for (int Pos = 0; Pos < 20; Pos += 4) {
4384       Vals[Pos / 4] = support::endian::read32be(Hash.data() + Pos);
4385     }
4386 
4387     // Emit the finished record.
4388     Stream.EmitRecord(bitc::MODULE_CODE_HASH, Vals);
4389 
4390     if (ModHash)
4391       // Save the written hash value.
4392       llvm::copy(Vals, std::begin(*ModHash));
4393   }
4394 }
4395 
4396 void ModuleBitcodeWriter::write() {
4397   writeIdentificationBlock(Stream);
4398 
4399   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4400   size_t BlockStartPos = Buffer.size();
4401 
4402   writeModuleVersion();
4403 
4404   // Emit blockinfo, which defines the standard abbreviations etc.
4405   writeBlockInfo();
4406 
4407   // Emit information describing all of the types in the module.
4408   writeTypeTable();
4409 
4410   // Emit information about attribute groups.
4411   writeAttributeGroupTable();
4412 
4413   // Emit information about parameter attributes.
4414   writeAttributeTable();
4415 
4416   writeComdats();
4417 
4418   // Emit top-level description of module, including target triple, inline asm,
4419   // descriptors for global variables, and function prototype info.
4420   writeModuleInfo();
4421 
4422   // Emit constants.
4423   writeModuleConstants();
4424 
4425   // Emit metadata kind names.
4426   writeModuleMetadataKinds();
4427 
4428   // Emit metadata.
4429   writeModuleMetadata();
4430 
4431   // Emit module-level use-lists.
4432   if (VE.shouldPreserveUseListOrder())
4433     writeUseListBlock(nullptr);
4434 
4435   writeOperandBundleTags();
4436   writeSyncScopeNames();
4437 
4438   // Emit function bodies.
4439   DenseMap<const Function *, uint64_t> FunctionToBitcodeIndex;
4440   for (Module::const_iterator F = M.begin(), E = M.end(); F != E; ++F)
4441     if (!F->isDeclaration())
4442       writeFunction(*F, FunctionToBitcodeIndex);
4443 
4444   // Need to write after the above call to WriteFunction which populates
4445   // the summary information in the index.
4446   if (Index)
4447     writePerModuleGlobalValueSummary();
4448 
4449   writeGlobalValueSymbolTable(FunctionToBitcodeIndex);
4450 
4451   writeModuleHash(BlockStartPos);
4452 
4453   Stream.ExitBlock();
4454 }
4455 
4456 static void writeInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
4457                                uint32_t &Position) {
4458   support::endian::write32le(&Buffer[Position], Value);
4459   Position += 4;
4460 }
4461 
4462 /// If generating a bc file on darwin, we have to emit a
4463 /// header and trailer to make it compatible with the system archiver.  To do
4464 /// this we emit the following header, and then emit a trailer that pads the
4465 /// file out to be a multiple of 16 bytes.
4466 ///
4467 /// struct bc_header {
4468 ///   uint32_t Magic;         // 0x0B17C0DE
4469 ///   uint32_t Version;       // Version, currently always 0.
4470 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
4471 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
4472 ///   uint32_t CPUType;       // CPU specifier.
4473 ///   ... potentially more later ...
4474 /// };
4475 static void emitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
4476                                          const Triple &TT) {
4477   unsigned CPUType = ~0U;
4478 
4479   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
4480   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
4481   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
4482   // specific constants here because they are implicitly part of the Darwin ABI.
4483   enum {
4484     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
4485     DARWIN_CPU_TYPE_X86        = 7,
4486     DARWIN_CPU_TYPE_ARM        = 12,
4487     DARWIN_CPU_TYPE_POWERPC    = 18
4488   };
4489 
4490   Triple::ArchType Arch = TT.getArch();
4491   if (Arch == Triple::x86_64)
4492     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
4493   else if (Arch == Triple::x86)
4494     CPUType = DARWIN_CPU_TYPE_X86;
4495   else if (Arch == Triple::ppc)
4496     CPUType = DARWIN_CPU_TYPE_POWERPC;
4497   else if (Arch == Triple::ppc64)
4498     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
4499   else if (Arch == Triple::arm || Arch == Triple::thumb)
4500     CPUType = DARWIN_CPU_TYPE_ARM;
4501 
4502   // Traditional Bitcode starts after header.
4503   assert(Buffer.size() >= BWH_HeaderSize &&
4504          "Expected header size to be reserved");
4505   unsigned BCOffset = BWH_HeaderSize;
4506   unsigned BCSize = Buffer.size() - BWH_HeaderSize;
4507 
4508   // Write the magic and version.
4509   unsigned Position = 0;
4510   writeInt32ToBuffer(0x0B17C0DE, Buffer, Position);
4511   writeInt32ToBuffer(0, Buffer, Position); // Version.
4512   writeInt32ToBuffer(BCOffset, Buffer, Position);
4513   writeInt32ToBuffer(BCSize, Buffer, Position);
4514   writeInt32ToBuffer(CPUType, Buffer, Position);
4515 
4516   // If the file is not a multiple of 16 bytes, insert dummy padding.
4517   while (Buffer.size() & 15)
4518     Buffer.push_back(0);
4519 }
4520 
4521 /// Helper to write the header common to all bitcode files.
4522 static void writeBitcodeHeader(BitstreamWriter &Stream) {
4523   // Emit the file header.
4524   Stream.Emit((unsigned)'B', 8);
4525   Stream.Emit((unsigned)'C', 8);
4526   Stream.Emit(0x0, 4);
4527   Stream.Emit(0xC, 4);
4528   Stream.Emit(0xE, 4);
4529   Stream.Emit(0xD, 4);
4530 }
4531 
4532 BitcodeWriter::BitcodeWriter(SmallVectorImpl<char> &Buffer, raw_fd_stream *FS)
4533     : Buffer(Buffer), Stream(new BitstreamWriter(Buffer, FS, FlushThreshold)) {
4534   writeBitcodeHeader(*Stream);
4535 }
4536 
4537 BitcodeWriter::~BitcodeWriter() { assert(WroteStrtab); }
4538 
4539 void BitcodeWriter::writeBlob(unsigned Block, unsigned Record, StringRef Blob) {
4540   Stream->EnterSubblock(Block, 3);
4541 
4542   auto Abbv = std::make_shared<BitCodeAbbrev>();
4543   Abbv->Add(BitCodeAbbrevOp(Record));
4544   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
4545   auto AbbrevNo = Stream->EmitAbbrev(std::move(Abbv));
4546 
4547   Stream->EmitRecordWithBlob(AbbrevNo, ArrayRef<uint64_t>{Record}, Blob);
4548 
4549   Stream->ExitBlock();
4550 }
4551 
4552 void BitcodeWriter::writeSymtab() {
4553   assert(!WroteStrtab && !WroteSymtab);
4554 
4555   // If any module has module-level inline asm, we will require a registered asm
4556   // parser for the target so that we can create an accurate symbol table for
4557   // the module.
4558   for (Module *M : Mods) {
4559     if (M->getModuleInlineAsm().empty())
4560       continue;
4561 
4562     std::string Err;
4563     const Triple TT(M->getTargetTriple());
4564     const Target *T = TargetRegistry::lookupTarget(TT.str(), Err);
4565     if (!T || !T->hasMCAsmParser())
4566       return;
4567   }
4568 
4569   WroteSymtab = true;
4570   SmallVector<char, 0> Symtab;
4571   // The irsymtab::build function may be unable to create a symbol table if the
4572   // module is malformed (e.g. it contains an invalid alias). Writing a symbol
4573   // table is not required for correctness, but we still want to be able to
4574   // write malformed modules to bitcode files, so swallow the error.
4575   if (Error E = irsymtab::build(Mods, Symtab, StrtabBuilder, Alloc)) {
4576     consumeError(std::move(E));
4577     return;
4578   }
4579 
4580   writeBlob(bitc::SYMTAB_BLOCK_ID, bitc::SYMTAB_BLOB,
4581             {Symtab.data(), Symtab.size()});
4582 }
4583 
4584 void BitcodeWriter::writeStrtab() {
4585   assert(!WroteStrtab);
4586 
4587   std::vector<char> Strtab;
4588   StrtabBuilder.finalizeInOrder();
4589   Strtab.resize(StrtabBuilder.getSize());
4590   StrtabBuilder.write((uint8_t *)Strtab.data());
4591 
4592   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB,
4593             {Strtab.data(), Strtab.size()});
4594 
4595   WroteStrtab = true;
4596 }
4597 
4598 void BitcodeWriter::copyStrtab(StringRef Strtab) {
4599   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB, Strtab);
4600   WroteStrtab = true;
4601 }
4602 
4603 void BitcodeWriter::writeModule(const Module &M,
4604                                 bool ShouldPreserveUseListOrder,
4605                                 const ModuleSummaryIndex *Index,
4606                                 bool GenerateHash, ModuleHash *ModHash) {
4607   assert(!WroteStrtab);
4608 
4609   // The Mods vector is used by irsymtab::build, which requires non-const
4610   // Modules in case it needs to materialize metadata. But the bitcode writer
4611   // requires that the module is materialized, so we can cast to non-const here,
4612   // after checking that it is in fact materialized.
4613   assert(M.isMaterialized());
4614   Mods.push_back(const_cast<Module *>(&M));
4615 
4616   ModuleBitcodeWriter ModuleWriter(M, Buffer, StrtabBuilder, *Stream,
4617                                    ShouldPreserveUseListOrder, Index,
4618                                    GenerateHash, ModHash);
4619   ModuleWriter.write();
4620 }
4621 
4622 void BitcodeWriter::writeIndex(
4623     const ModuleSummaryIndex *Index,
4624     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4625   IndexBitcodeWriter IndexWriter(*Stream, StrtabBuilder, *Index,
4626                                  ModuleToSummariesForIndex);
4627   IndexWriter.write();
4628 }
4629 
4630 /// Write the specified module to the specified output stream.
4631 void llvm::WriteBitcodeToFile(const Module &M, raw_ostream &Out,
4632                               bool ShouldPreserveUseListOrder,
4633                               const ModuleSummaryIndex *Index,
4634                               bool GenerateHash, ModuleHash *ModHash) {
4635   SmallVector<char, 0> Buffer;
4636   Buffer.reserve(256*1024);
4637 
4638   // If this is darwin or another generic macho target, reserve space for the
4639   // header.
4640   Triple TT(M.getTargetTriple());
4641   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4642     Buffer.insert(Buffer.begin(), BWH_HeaderSize, 0);
4643 
4644   BitcodeWriter Writer(Buffer, dyn_cast<raw_fd_stream>(&Out));
4645   Writer.writeModule(M, ShouldPreserveUseListOrder, Index, GenerateHash,
4646                      ModHash);
4647   Writer.writeSymtab();
4648   Writer.writeStrtab();
4649 
4650   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4651     emitDarwinBCHeaderAndTrailer(Buffer, TT);
4652 
4653   // Write the generated bitstream to "Out".
4654   if (!Buffer.empty())
4655     Out.write((char *)&Buffer.front(), Buffer.size());
4656 }
4657 
4658 void IndexBitcodeWriter::write() {
4659   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4660 
4661   writeModuleVersion();
4662 
4663   // Write the module paths in the combined index.
4664   writeModStrings();
4665 
4666   // Write the summary combined index records.
4667   writeCombinedGlobalValueSummary();
4668 
4669   Stream.ExitBlock();
4670 }
4671 
4672 // Write the specified module summary index to the given raw output stream,
4673 // where it will be written in a new bitcode block. This is used when
4674 // writing the combined index file for ThinLTO. When writing a subset of the
4675 // index for a distributed backend, provide a \p ModuleToSummariesForIndex map.
4676 void llvm::WriteIndexToFile(
4677     const ModuleSummaryIndex &Index, raw_ostream &Out,
4678     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4679   SmallVector<char, 0> Buffer;
4680   Buffer.reserve(256 * 1024);
4681 
4682   BitcodeWriter Writer(Buffer);
4683   Writer.writeIndex(&Index, ModuleToSummariesForIndex);
4684   Writer.writeStrtab();
4685 
4686   Out.write((char *)&Buffer.front(), Buffer.size());
4687 }
4688 
4689 namespace {
4690 
4691 /// Class to manage the bitcode writing for a thin link bitcode file.
4692 class ThinLinkBitcodeWriter : public ModuleBitcodeWriterBase {
4693   /// ModHash is for use in ThinLTO incremental build, generated while writing
4694   /// the module bitcode file.
4695   const ModuleHash *ModHash;
4696 
4697 public:
4698   ThinLinkBitcodeWriter(const Module &M, StringTableBuilder &StrtabBuilder,
4699                         BitstreamWriter &Stream,
4700                         const ModuleSummaryIndex &Index,
4701                         const ModuleHash &ModHash)
4702       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
4703                                 /*ShouldPreserveUseListOrder=*/false, &Index),
4704         ModHash(&ModHash) {}
4705 
4706   void write();
4707 
4708 private:
4709   void writeSimplifiedModuleInfo();
4710 };
4711 
4712 } // end anonymous namespace
4713 
4714 // This function writes a simpilified module info for thin link bitcode file.
4715 // It only contains the source file name along with the name(the offset and
4716 // size in strtab) and linkage for global values. For the global value info
4717 // entry, in order to keep linkage at offset 5, there are three zeros used
4718 // as padding.
4719 void ThinLinkBitcodeWriter::writeSimplifiedModuleInfo() {
4720   SmallVector<unsigned, 64> Vals;
4721   // Emit the module's source file name.
4722   {
4723     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
4724     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
4725     if (Bits == SE_Char6)
4726       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
4727     else if (Bits == SE_Fixed7)
4728       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
4729 
4730     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
4731     auto Abbv = std::make_shared<BitCodeAbbrev>();
4732     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
4733     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4734     Abbv->Add(AbbrevOpToUse);
4735     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4736 
4737     for (const auto P : M.getSourceFileName())
4738       Vals.push_back((unsigned char)P);
4739 
4740     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
4741     Vals.clear();
4742   }
4743 
4744   // Emit the global variable information.
4745   for (const GlobalVariable &GV : M.globals()) {
4746     // GLOBALVAR: [strtab offset, strtab size, 0, 0, 0, linkage]
4747     Vals.push_back(StrtabBuilder.add(GV.getName()));
4748     Vals.push_back(GV.getName().size());
4749     Vals.push_back(0);
4750     Vals.push_back(0);
4751     Vals.push_back(0);
4752     Vals.push_back(getEncodedLinkage(GV));
4753 
4754     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals);
4755     Vals.clear();
4756   }
4757 
4758   // Emit the function proto information.
4759   for (const Function &F : M) {
4760     // FUNCTION:  [strtab offset, strtab size, 0, 0, 0, linkage]
4761     Vals.push_back(StrtabBuilder.add(F.getName()));
4762     Vals.push_back(F.getName().size());
4763     Vals.push_back(0);
4764     Vals.push_back(0);
4765     Vals.push_back(0);
4766     Vals.push_back(getEncodedLinkage(F));
4767 
4768     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals);
4769     Vals.clear();
4770   }
4771 
4772   // Emit the alias information.
4773   for (const GlobalAlias &A : M.aliases()) {
4774     // ALIAS: [strtab offset, strtab size, 0, 0, 0, linkage]
4775     Vals.push_back(StrtabBuilder.add(A.getName()));
4776     Vals.push_back(A.getName().size());
4777     Vals.push_back(0);
4778     Vals.push_back(0);
4779     Vals.push_back(0);
4780     Vals.push_back(getEncodedLinkage(A));
4781 
4782     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals);
4783     Vals.clear();
4784   }
4785 
4786   // Emit the ifunc information.
4787   for (const GlobalIFunc &I : M.ifuncs()) {
4788     // IFUNC: [strtab offset, strtab size, 0, 0, 0, linkage]
4789     Vals.push_back(StrtabBuilder.add(I.getName()));
4790     Vals.push_back(I.getName().size());
4791     Vals.push_back(0);
4792     Vals.push_back(0);
4793     Vals.push_back(0);
4794     Vals.push_back(getEncodedLinkage(I));
4795 
4796     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
4797     Vals.clear();
4798   }
4799 }
4800 
4801 void ThinLinkBitcodeWriter::write() {
4802   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4803 
4804   writeModuleVersion();
4805 
4806   writeSimplifiedModuleInfo();
4807 
4808   writePerModuleGlobalValueSummary();
4809 
4810   // Write module hash.
4811   Stream.EmitRecord(bitc::MODULE_CODE_HASH, ArrayRef<uint32_t>(*ModHash));
4812 
4813   Stream.ExitBlock();
4814 }
4815 
4816 void BitcodeWriter::writeThinLinkBitcode(const Module &M,
4817                                          const ModuleSummaryIndex &Index,
4818                                          const ModuleHash &ModHash) {
4819   assert(!WroteStrtab);
4820 
4821   // The Mods vector is used by irsymtab::build, which requires non-const
4822   // Modules in case it needs to materialize metadata. But the bitcode writer
4823   // requires that the module is materialized, so we can cast to non-const here,
4824   // after checking that it is in fact materialized.
4825   assert(M.isMaterialized());
4826   Mods.push_back(const_cast<Module *>(&M));
4827 
4828   ThinLinkBitcodeWriter ThinLinkWriter(M, StrtabBuilder, *Stream, Index,
4829                                        ModHash);
4830   ThinLinkWriter.write();
4831 }
4832 
4833 // Write the specified thin link bitcode file to the given raw output stream,
4834 // where it will be written in a new bitcode block. This is used when
4835 // writing the per-module index file for ThinLTO.
4836 void llvm::WriteThinLinkBitcodeToFile(const Module &M, raw_ostream &Out,
4837                                       const ModuleSummaryIndex &Index,
4838                                       const ModuleHash &ModHash) {
4839   SmallVector<char, 0> Buffer;
4840   Buffer.reserve(256 * 1024);
4841 
4842   BitcodeWriter Writer(Buffer);
4843   Writer.writeThinLinkBitcode(M, Index, ModHash);
4844   Writer.writeSymtab();
4845   Writer.writeStrtab();
4846 
4847   Out.write((char *)&Buffer.front(), Buffer.size());
4848 }
4849 
4850 static const char *getSectionNameForBitcode(const Triple &T) {
4851   switch (T.getObjectFormat()) {
4852   case Triple::MachO:
4853     return "__LLVM,__bitcode";
4854   case Triple::COFF:
4855   case Triple::ELF:
4856   case Triple::Wasm:
4857   case Triple::UnknownObjectFormat:
4858     return ".llvmbc";
4859   case Triple::GOFF:
4860     llvm_unreachable("GOFF is not yet implemented");
4861     break;
4862   case Triple::XCOFF:
4863     llvm_unreachable("XCOFF is not yet implemented");
4864     break;
4865   }
4866   llvm_unreachable("Unimplemented ObjectFormatType");
4867 }
4868 
4869 static const char *getSectionNameForCommandline(const Triple &T) {
4870   switch (T.getObjectFormat()) {
4871   case Triple::MachO:
4872     return "__LLVM,__cmdline";
4873   case Triple::COFF:
4874   case Triple::ELF:
4875   case Triple::Wasm:
4876   case Triple::UnknownObjectFormat:
4877     return ".llvmcmd";
4878   case Triple::GOFF:
4879     llvm_unreachable("GOFF is not yet implemented");
4880     break;
4881   case Triple::XCOFF:
4882     llvm_unreachable("XCOFF is not yet implemented");
4883     break;
4884   }
4885   llvm_unreachable("Unimplemented ObjectFormatType");
4886 }
4887 
4888 void llvm::EmbedBitcodeInModule(llvm::Module &M, llvm::MemoryBufferRef Buf,
4889                                 bool EmbedBitcode, bool EmbedCmdline,
4890                                 const std::vector<uint8_t> &CmdArgs) {
4891   // Save llvm.compiler.used and remove it.
4892   SmallVector<Constant *, 2> UsedArray;
4893   SmallVector<GlobalValue *, 4> UsedGlobals;
4894   Type *UsedElementType = Type::getInt8Ty(M.getContext())->getPointerTo(0);
4895   GlobalVariable *Used = collectUsedGlobalVariables(M, UsedGlobals, true);
4896   for (auto *GV : UsedGlobals) {
4897     if (GV->getName() != "llvm.embedded.module" &&
4898         GV->getName() != "llvm.cmdline")
4899       UsedArray.push_back(
4900           ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
4901   }
4902   if (Used)
4903     Used->eraseFromParent();
4904 
4905   // Embed the bitcode for the llvm module.
4906   std::string Data;
4907   ArrayRef<uint8_t> ModuleData;
4908   Triple T(M.getTargetTriple());
4909 
4910   if (EmbedBitcode) {
4911     if (Buf.getBufferSize() == 0 ||
4912         !isBitcode((const unsigned char *)Buf.getBufferStart(),
4913                    (const unsigned char *)Buf.getBufferEnd())) {
4914       // If the input is LLVM Assembly, bitcode is produced by serializing
4915       // the module. Use-lists order need to be preserved in this case.
4916       llvm::raw_string_ostream OS(Data);
4917       llvm::WriteBitcodeToFile(M, OS, /* ShouldPreserveUseListOrder */ true);
4918       ModuleData =
4919           ArrayRef<uint8_t>((const uint8_t *)OS.str().data(), OS.str().size());
4920     } else
4921       // If the input is LLVM bitcode, write the input byte stream directly.
4922       ModuleData = ArrayRef<uint8_t>((const uint8_t *)Buf.getBufferStart(),
4923                                      Buf.getBufferSize());
4924   }
4925   llvm::Constant *ModuleConstant =
4926       llvm::ConstantDataArray::get(M.getContext(), ModuleData);
4927   llvm::GlobalVariable *GV = new llvm::GlobalVariable(
4928       M, ModuleConstant->getType(), true, llvm::GlobalValue::PrivateLinkage,
4929       ModuleConstant);
4930   GV->setSection(getSectionNameForBitcode(T));
4931   // Set alignment to 1 to prevent padding between two contributions from input
4932   // sections after linking.
4933   GV->setAlignment(Align(1));
4934   UsedArray.push_back(
4935       ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
4936   if (llvm::GlobalVariable *Old =
4937           M.getGlobalVariable("llvm.embedded.module", true)) {
4938     assert(Old->hasOneUse() &&
4939            "llvm.embedded.module can only be used once in llvm.compiler.used");
4940     GV->takeName(Old);
4941     Old->eraseFromParent();
4942   } else {
4943     GV->setName("llvm.embedded.module");
4944   }
4945 
4946   // Skip if only bitcode needs to be embedded.
4947   if (EmbedCmdline) {
4948     // Embed command-line options.
4949     ArrayRef<uint8_t> CmdData(const_cast<uint8_t *>(CmdArgs.data()),
4950                               CmdArgs.size());
4951     llvm::Constant *CmdConstant =
4952         llvm::ConstantDataArray::get(M.getContext(), CmdData);
4953     GV = new llvm::GlobalVariable(M, CmdConstant->getType(), true,
4954                                   llvm::GlobalValue::PrivateLinkage,
4955                                   CmdConstant);
4956     GV->setSection(getSectionNameForCommandline(T));
4957     GV->setAlignment(Align(1));
4958     UsedArray.push_back(
4959         ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
4960     if (llvm::GlobalVariable *Old = M.getGlobalVariable("llvm.cmdline", true)) {
4961       assert(Old->hasOneUse() &&
4962              "llvm.cmdline can only be used once in llvm.compiler.used");
4963       GV->takeName(Old);
4964       Old->eraseFromParent();
4965     } else {
4966       GV->setName("llvm.cmdline");
4967     }
4968   }
4969 
4970   if (UsedArray.empty())
4971     return;
4972 
4973   // Recreate llvm.compiler.used.
4974   ArrayType *ATy = ArrayType::get(UsedElementType, UsedArray.size());
4975   auto *NewUsed = new GlobalVariable(
4976       M, ATy, false, llvm::GlobalValue::AppendingLinkage,
4977       llvm::ConstantArray::get(ATy, UsedArray), "llvm.compiler.used");
4978   NewUsed->setSection("llvm.metadata");
4979 }
4980