xref: /llvm-project/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp (revision 62b1682570b1059e8c6542192159dcde32c13c30)
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/MC/TargetRegistry.h"
62 #include "llvm/Object/IRSymtab.h"
63 #include "llvm/Support/AtomicOrdering.h"
64 #include "llvm/Support/Casting.h"
65 #include "llvm/Support/CommandLine.h"
66 #include "llvm/Support/Endian.h"
67 #include "llvm/Support/Error.h"
68 #include "llvm/Support/ErrorHandling.h"
69 #include "llvm/Support/MathExtras.h"
70 #include "llvm/Support/SHA1.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 pushGlobalMetadataAttachment(SmallVectorImpl<uint64_t> &Record,
377                                     const GlobalObject &GO);
378   void writeModuleMetadataKinds();
379   void writeOperandBundleTags();
380   void writeSyncScopeNames();
381   void writeConstants(unsigned FirstVal, unsigned LastVal, bool isGlobal);
382   void writeModuleConstants();
383   bool pushValueAndType(const Value *V, unsigned InstID,
384                         SmallVectorImpl<unsigned> &Vals);
385   void writeOperandBundles(const CallBase &CB, unsigned InstID);
386   void pushValue(const Value *V, unsigned InstID,
387                  SmallVectorImpl<unsigned> &Vals);
388   void pushValueSigned(const Value *V, unsigned InstID,
389                        SmallVectorImpl<uint64_t> &Vals);
390   void writeInstruction(const Instruction &I, unsigned InstID,
391                         SmallVectorImpl<unsigned> &Vals);
392   void writeFunctionLevelValueSymbolTable(const ValueSymbolTable &VST);
393   void writeGlobalValueSymbolTable(
394       DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
395   void writeUseList(UseListOrder &&Order);
396   void writeUseListBlock(const Function *F);
397   void
398   writeFunction(const Function &F,
399                 DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
400   void writeBlockInfo();
401   void writeModuleHash(size_t BlockStartPos);
402 
403   unsigned getEncodedSyncScopeID(SyncScope::ID SSID) {
404     return unsigned(SSID);
405   }
406 
407   unsigned getEncodedAlign(MaybeAlign Alignment) { return encode(Alignment); }
408 };
409 
410 /// Class to manage the bitcode writing for a combined index.
411 class IndexBitcodeWriter : public BitcodeWriterBase {
412   /// The combined index to write to bitcode.
413   const ModuleSummaryIndex &Index;
414 
415   /// When writing a subset of the index for distributed backends, client
416   /// provides a map of modules to the corresponding GUIDs/summaries to write.
417   const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex;
418 
419   /// Map that holds the correspondence between the GUID used in the combined
420   /// index and a value id generated by this class to use in references.
421   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
422 
423   /// Tracks the last value id recorded in the GUIDToValueMap.
424   unsigned GlobalValueId = 0;
425 
426 public:
427   /// Constructs a IndexBitcodeWriter object for the given combined index,
428   /// writing to the provided \p Buffer. When writing a subset of the index
429   /// for a distributed backend, provide a \p ModuleToSummariesForIndex map.
430   IndexBitcodeWriter(BitstreamWriter &Stream, StringTableBuilder &StrtabBuilder,
431                      const ModuleSummaryIndex &Index,
432                      const std::map<std::string, GVSummaryMapTy>
433                          *ModuleToSummariesForIndex = nullptr)
434       : BitcodeWriterBase(Stream, StrtabBuilder), Index(Index),
435         ModuleToSummariesForIndex(ModuleToSummariesForIndex) {
436     // Assign unique value ids to all summaries to be written, for use
437     // in writing out the call graph edges. Save the mapping from GUID
438     // to the new global value id to use when writing those edges, which
439     // are currently saved in the index in terms of GUID.
440     forEachSummary([&](GVInfo I, bool) {
441       GUIDToValueIdMap[I.first] = ++GlobalValueId;
442     });
443   }
444 
445   /// The below iterator returns the GUID and associated summary.
446   using GVInfo = std::pair<GlobalValue::GUID, GlobalValueSummary *>;
447 
448   /// Calls the callback for each value GUID and summary to be written to
449   /// bitcode. This hides the details of whether they are being pulled from the
450   /// entire index or just those in a provided ModuleToSummariesForIndex map.
451   template<typename Functor>
452   void forEachSummary(Functor Callback) {
453     if (ModuleToSummariesForIndex) {
454       for (auto &M : *ModuleToSummariesForIndex)
455         for (auto &Summary : M.second) {
456           Callback(Summary, false);
457           // Ensure aliasee is handled, e.g. for assigning a valueId,
458           // even if we are not importing the aliasee directly (the
459           // imported alias will contain a copy of aliasee).
460           if (auto *AS = dyn_cast<AliasSummary>(Summary.getSecond()))
461             Callback({AS->getAliaseeGUID(), &AS->getAliasee()}, true);
462         }
463     } else {
464       for (auto &Summaries : Index)
465         for (auto &Summary : Summaries.second.SummaryList)
466           Callback({Summaries.first, Summary.get()}, false);
467     }
468   }
469 
470   /// Calls the callback for each entry in the modulePaths StringMap that
471   /// should be written to the module path string table. This hides the details
472   /// of whether they are being pulled from the entire index or just those in a
473   /// provided ModuleToSummariesForIndex map.
474   template <typename Functor> void forEachModule(Functor Callback) {
475     if (ModuleToSummariesForIndex) {
476       for (const auto &M : *ModuleToSummariesForIndex) {
477         const auto &MPI = Index.modulePaths().find(M.first);
478         if (MPI == Index.modulePaths().end()) {
479           // This should only happen if the bitcode file was empty, in which
480           // case we shouldn't be importing (the ModuleToSummariesForIndex
481           // would only include the module we are writing and index for).
482           assert(ModuleToSummariesForIndex->size() == 1);
483           continue;
484         }
485         Callback(*MPI);
486       }
487     } else {
488       for (const auto &MPSE : Index.modulePaths())
489         Callback(MPSE);
490     }
491   }
492 
493   /// Main entry point for writing a combined index to bitcode.
494   void write();
495 
496 private:
497   void writeModStrings();
498   void writeCombinedGlobalValueSummary();
499 
500   Optional<unsigned> getValueId(GlobalValue::GUID ValGUID) {
501     auto VMI = GUIDToValueIdMap.find(ValGUID);
502     if (VMI == GUIDToValueIdMap.end())
503       return None;
504     return VMI->second;
505   }
506 
507   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
508 };
509 
510 } // end anonymous namespace
511 
512 static unsigned getEncodedCastOpcode(unsigned Opcode) {
513   switch (Opcode) {
514   default: llvm_unreachable("Unknown cast instruction!");
515   case Instruction::Trunc   : return bitc::CAST_TRUNC;
516   case Instruction::ZExt    : return bitc::CAST_ZEXT;
517   case Instruction::SExt    : return bitc::CAST_SEXT;
518   case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
519   case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
520   case Instruction::UIToFP  : return bitc::CAST_UITOFP;
521   case Instruction::SIToFP  : return bitc::CAST_SITOFP;
522   case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
523   case Instruction::FPExt   : return bitc::CAST_FPEXT;
524   case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
525   case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
526   case Instruction::BitCast : return bitc::CAST_BITCAST;
527   case Instruction::AddrSpaceCast: return bitc::CAST_ADDRSPACECAST;
528   }
529 }
530 
531 static unsigned getEncodedUnaryOpcode(unsigned Opcode) {
532   switch (Opcode) {
533   default: llvm_unreachable("Unknown binary instruction!");
534   case Instruction::FNeg: return bitc::UNOP_FNEG;
535   }
536 }
537 
538 static unsigned getEncodedBinaryOpcode(unsigned Opcode) {
539   switch (Opcode) {
540   default: llvm_unreachable("Unknown binary instruction!");
541   case Instruction::Add:
542   case Instruction::FAdd: return bitc::BINOP_ADD;
543   case Instruction::Sub:
544   case Instruction::FSub: return bitc::BINOP_SUB;
545   case Instruction::Mul:
546   case Instruction::FMul: return bitc::BINOP_MUL;
547   case Instruction::UDiv: return bitc::BINOP_UDIV;
548   case Instruction::FDiv:
549   case Instruction::SDiv: return bitc::BINOP_SDIV;
550   case Instruction::URem: return bitc::BINOP_UREM;
551   case Instruction::FRem:
552   case Instruction::SRem: return bitc::BINOP_SREM;
553   case Instruction::Shl:  return bitc::BINOP_SHL;
554   case Instruction::LShr: return bitc::BINOP_LSHR;
555   case Instruction::AShr: return bitc::BINOP_ASHR;
556   case Instruction::And:  return bitc::BINOP_AND;
557   case Instruction::Or:   return bitc::BINOP_OR;
558   case Instruction::Xor:  return bitc::BINOP_XOR;
559   }
560 }
561 
562 static unsigned getEncodedRMWOperation(AtomicRMWInst::BinOp Op) {
563   switch (Op) {
564   default: llvm_unreachable("Unknown RMW operation!");
565   case AtomicRMWInst::Xchg: return bitc::RMW_XCHG;
566   case AtomicRMWInst::Add: return bitc::RMW_ADD;
567   case AtomicRMWInst::Sub: return bitc::RMW_SUB;
568   case AtomicRMWInst::And: return bitc::RMW_AND;
569   case AtomicRMWInst::Nand: return bitc::RMW_NAND;
570   case AtomicRMWInst::Or: return bitc::RMW_OR;
571   case AtomicRMWInst::Xor: return bitc::RMW_XOR;
572   case AtomicRMWInst::Max: return bitc::RMW_MAX;
573   case AtomicRMWInst::Min: return bitc::RMW_MIN;
574   case AtomicRMWInst::UMax: return bitc::RMW_UMAX;
575   case AtomicRMWInst::UMin: return bitc::RMW_UMIN;
576   case AtomicRMWInst::FAdd: return bitc::RMW_FADD;
577   case AtomicRMWInst::FSub: return bitc::RMW_FSUB;
578   }
579 }
580 
581 static unsigned getEncodedOrdering(AtomicOrdering Ordering) {
582   switch (Ordering) {
583   case AtomicOrdering::NotAtomic: return bitc::ORDERING_NOTATOMIC;
584   case AtomicOrdering::Unordered: return bitc::ORDERING_UNORDERED;
585   case AtomicOrdering::Monotonic: return bitc::ORDERING_MONOTONIC;
586   case AtomicOrdering::Acquire: return bitc::ORDERING_ACQUIRE;
587   case AtomicOrdering::Release: return bitc::ORDERING_RELEASE;
588   case AtomicOrdering::AcquireRelease: return bitc::ORDERING_ACQREL;
589   case AtomicOrdering::SequentiallyConsistent: return bitc::ORDERING_SEQCST;
590   }
591   llvm_unreachable("Invalid ordering");
592 }
593 
594 static void writeStringRecord(BitstreamWriter &Stream, unsigned Code,
595                               StringRef Str, unsigned AbbrevToUse) {
596   SmallVector<unsigned, 64> Vals;
597 
598   // Code: [strchar x N]
599   for (char C : Str) {
600     if (AbbrevToUse && !BitCodeAbbrevOp::isChar6(C))
601       AbbrevToUse = 0;
602     Vals.push_back(C);
603   }
604 
605   // Emit the finished record.
606   Stream.EmitRecord(Code, Vals, AbbrevToUse);
607 }
608 
609 static uint64_t getAttrKindEncoding(Attribute::AttrKind Kind) {
610   switch (Kind) {
611   case Attribute::Alignment:
612     return bitc::ATTR_KIND_ALIGNMENT;
613   case Attribute::AllocSize:
614     return bitc::ATTR_KIND_ALLOC_SIZE;
615   case Attribute::AlwaysInline:
616     return bitc::ATTR_KIND_ALWAYS_INLINE;
617   case Attribute::ArgMemOnly:
618     return bitc::ATTR_KIND_ARGMEMONLY;
619   case Attribute::Builtin:
620     return bitc::ATTR_KIND_BUILTIN;
621   case Attribute::ByVal:
622     return bitc::ATTR_KIND_BY_VAL;
623   case Attribute::Convergent:
624     return bitc::ATTR_KIND_CONVERGENT;
625   case Attribute::InAlloca:
626     return bitc::ATTR_KIND_IN_ALLOCA;
627   case Attribute::Cold:
628     return bitc::ATTR_KIND_COLD;
629   case Attribute::DisableSanitizerInstrumentation:
630     return bitc::ATTR_KIND_DISABLE_SANITIZER_INSTRUMENTATION;
631   case Attribute::Hot:
632     return bitc::ATTR_KIND_HOT;
633   case Attribute::ElementType:
634     return bitc::ATTR_KIND_ELEMENTTYPE;
635   case Attribute::InaccessibleMemOnly:
636     return bitc::ATTR_KIND_INACCESSIBLEMEM_ONLY;
637   case Attribute::InaccessibleMemOrArgMemOnly:
638     return bitc::ATTR_KIND_INACCESSIBLEMEM_OR_ARGMEMONLY;
639   case Attribute::InlineHint:
640     return bitc::ATTR_KIND_INLINE_HINT;
641   case Attribute::InReg:
642     return bitc::ATTR_KIND_IN_REG;
643   case Attribute::JumpTable:
644     return bitc::ATTR_KIND_JUMP_TABLE;
645   case Attribute::MinSize:
646     return bitc::ATTR_KIND_MIN_SIZE;
647   case Attribute::Naked:
648     return bitc::ATTR_KIND_NAKED;
649   case Attribute::Nest:
650     return bitc::ATTR_KIND_NEST;
651   case Attribute::NoAlias:
652     return bitc::ATTR_KIND_NO_ALIAS;
653   case Attribute::NoBuiltin:
654     return bitc::ATTR_KIND_NO_BUILTIN;
655   case Attribute::NoCallback:
656     return bitc::ATTR_KIND_NO_CALLBACK;
657   case Attribute::NoCapture:
658     return bitc::ATTR_KIND_NO_CAPTURE;
659   case Attribute::NoDuplicate:
660     return bitc::ATTR_KIND_NO_DUPLICATE;
661   case Attribute::NoFree:
662     return bitc::ATTR_KIND_NOFREE;
663   case Attribute::NoImplicitFloat:
664     return bitc::ATTR_KIND_NO_IMPLICIT_FLOAT;
665   case Attribute::NoInline:
666     return bitc::ATTR_KIND_NO_INLINE;
667   case Attribute::NoRecurse:
668     return bitc::ATTR_KIND_NO_RECURSE;
669   case Attribute::NoMerge:
670     return bitc::ATTR_KIND_NO_MERGE;
671   case Attribute::NonLazyBind:
672     return bitc::ATTR_KIND_NON_LAZY_BIND;
673   case Attribute::NonNull:
674     return bitc::ATTR_KIND_NON_NULL;
675   case Attribute::Dereferenceable:
676     return bitc::ATTR_KIND_DEREFERENCEABLE;
677   case Attribute::DereferenceableOrNull:
678     return bitc::ATTR_KIND_DEREFERENCEABLE_OR_NULL;
679   case Attribute::NoRedZone:
680     return bitc::ATTR_KIND_NO_RED_ZONE;
681   case Attribute::NoReturn:
682     return bitc::ATTR_KIND_NO_RETURN;
683   case Attribute::NoSync:
684     return bitc::ATTR_KIND_NOSYNC;
685   case Attribute::NoCfCheck:
686     return bitc::ATTR_KIND_NOCF_CHECK;
687   case Attribute::NoProfile:
688     return bitc::ATTR_KIND_NO_PROFILE;
689   case Attribute::NoUnwind:
690     return bitc::ATTR_KIND_NO_UNWIND;
691   case Attribute::NoSanitizeCoverage:
692     return bitc::ATTR_KIND_NO_SANITIZE_COVERAGE;
693   case Attribute::NullPointerIsValid:
694     return bitc::ATTR_KIND_NULL_POINTER_IS_VALID;
695   case Attribute::OptForFuzzing:
696     return bitc::ATTR_KIND_OPT_FOR_FUZZING;
697   case Attribute::OptimizeForSize:
698     return bitc::ATTR_KIND_OPTIMIZE_FOR_SIZE;
699   case Attribute::OptimizeNone:
700     return bitc::ATTR_KIND_OPTIMIZE_NONE;
701   case Attribute::ReadNone:
702     return bitc::ATTR_KIND_READ_NONE;
703   case Attribute::ReadOnly:
704     return bitc::ATTR_KIND_READ_ONLY;
705   case Attribute::Returned:
706     return bitc::ATTR_KIND_RETURNED;
707   case Attribute::ReturnsTwice:
708     return bitc::ATTR_KIND_RETURNS_TWICE;
709   case Attribute::SExt:
710     return bitc::ATTR_KIND_S_EXT;
711   case Attribute::Speculatable:
712     return bitc::ATTR_KIND_SPECULATABLE;
713   case Attribute::StackAlignment:
714     return bitc::ATTR_KIND_STACK_ALIGNMENT;
715   case Attribute::StackProtect:
716     return bitc::ATTR_KIND_STACK_PROTECT;
717   case Attribute::StackProtectReq:
718     return bitc::ATTR_KIND_STACK_PROTECT_REQ;
719   case Attribute::StackProtectStrong:
720     return bitc::ATTR_KIND_STACK_PROTECT_STRONG;
721   case Attribute::SafeStack:
722     return bitc::ATTR_KIND_SAFESTACK;
723   case Attribute::ShadowCallStack:
724     return bitc::ATTR_KIND_SHADOWCALLSTACK;
725   case Attribute::StrictFP:
726     return bitc::ATTR_KIND_STRICT_FP;
727   case Attribute::StructRet:
728     return bitc::ATTR_KIND_STRUCT_RET;
729   case Attribute::SanitizeAddress:
730     return bitc::ATTR_KIND_SANITIZE_ADDRESS;
731   case Attribute::SanitizeHWAddress:
732     return bitc::ATTR_KIND_SANITIZE_HWADDRESS;
733   case Attribute::SanitizeThread:
734     return bitc::ATTR_KIND_SANITIZE_THREAD;
735   case Attribute::SanitizeMemory:
736     return bitc::ATTR_KIND_SANITIZE_MEMORY;
737   case Attribute::SpeculativeLoadHardening:
738     return bitc::ATTR_KIND_SPECULATIVE_LOAD_HARDENING;
739   case Attribute::SwiftError:
740     return bitc::ATTR_KIND_SWIFT_ERROR;
741   case Attribute::SwiftSelf:
742     return bitc::ATTR_KIND_SWIFT_SELF;
743   case Attribute::SwiftAsync:
744     return bitc::ATTR_KIND_SWIFT_ASYNC;
745   case Attribute::UWTable:
746     return bitc::ATTR_KIND_UW_TABLE;
747   case Attribute::VScaleRange:
748     return bitc::ATTR_KIND_VSCALE_RANGE;
749   case Attribute::WillReturn:
750     return bitc::ATTR_KIND_WILLRETURN;
751   case Attribute::WriteOnly:
752     return bitc::ATTR_KIND_WRITEONLY;
753   case Attribute::ZExt:
754     return bitc::ATTR_KIND_Z_EXT;
755   case Attribute::ImmArg:
756     return bitc::ATTR_KIND_IMMARG;
757   case Attribute::SanitizeMemTag:
758     return bitc::ATTR_KIND_SANITIZE_MEMTAG;
759   case Attribute::Preallocated:
760     return bitc::ATTR_KIND_PREALLOCATED;
761   case Attribute::NoUndef:
762     return bitc::ATTR_KIND_NOUNDEF;
763   case Attribute::ByRef:
764     return bitc::ATTR_KIND_BYREF;
765   case Attribute::MustProgress:
766     return bitc::ATTR_KIND_MUSTPROGRESS;
767   case Attribute::EndAttrKinds:
768     llvm_unreachable("Can not encode end-attribute kinds marker.");
769   case Attribute::None:
770     llvm_unreachable("Can not encode none-attribute.");
771   case Attribute::EmptyKey:
772   case Attribute::TombstoneKey:
773     llvm_unreachable("Trying to encode EmptyKey/TombstoneKey");
774   }
775 
776   llvm_unreachable("Trying to encode unknown attribute");
777 }
778 
779 void ModuleBitcodeWriter::writeAttributeGroupTable() {
780   const std::vector<ValueEnumerator::IndexAndAttrSet> &AttrGrps =
781       VE.getAttributeGroups();
782   if (AttrGrps.empty()) return;
783 
784   Stream.EnterSubblock(bitc::PARAMATTR_GROUP_BLOCK_ID, 3);
785 
786   SmallVector<uint64_t, 64> Record;
787   for (ValueEnumerator::IndexAndAttrSet Pair : AttrGrps) {
788     unsigned AttrListIndex = Pair.first;
789     AttributeSet AS = Pair.second;
790     Record.push_back(VE.getAttributeGroupID(Pair));
791     Record.push_back(AttrListIndex);
792 
793     for (Attribute Attr : AS) {
794       if (Attr.isEnumAttribute()) {
795         Record.push_back(0);
796         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
797       } else if (Attr.isIntAttribute()) {
798         Record.push_back(1);
799         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
800         Record.push_back(Attr.getValueAsInt());
801       } else if (Attr.isStringAttribute()) {
802         StringRef Kind = Attr.getKindAsString();
803         StringRef Val = Attr.getValueAsString();
804 
805         Record.push_back(Val.empty() ? 3 : 4);
806         Record.append(Kind.begin(), Kind.end());
807         Record.push_back(0);
808         if (!Val.empty()) {
809           Record.append(Val.begin(), Val.end());
810           Record.push_back(0);
811         }
812       } else {
813         assert(Attr.isTypeAttribute());
814         Type *Ty = Attr.getValueAsType();
815         Record.push_back(Ty ? 6 : 5);
816         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
817         if (Ty)
818           Record.push_back(VE.getTypeID(Attr.getValueAsType()));
819       }
820     }
821 
822     Stream.EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
823     Record.clear();
824   }
825 
826   Stream.ExitBlock();
827 }
828 
829 void ModuleBitcodeWriter::writeAttributeTable() {
830   const std::vector<AttributeList> &Attrs = VE.getAttributeLists();
831   if (Attrs.empty()) return;
832 
833   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
834 
835   SmallVector<uint64_t, 64> Record;
836   for (const AttributeList &AL : Attrs) {
837     for (unsigned i : AL.indexes()) {
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 (Type *T : TypeList) {
917     int AbbrevToUse = 0;
918     unsigned Code = 0;
919 
920     switch (T->getTypeID()) {
921     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;      break;
922     case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;      break;
923     case Type::BFloatTyID:    Code = bitc::TYPE_CODE_BFLOAT;    break;
924     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;     break;
925     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE;    break;
926     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80;  break;
927     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128;     break;
928     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
929     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;     break;
930     case Type::MetadataTyID:  Code = bitc::TYPE_CODE_METADATA;  break;
931     case Type::X86_MMXTyID:   Code = bitc::TYPE_CODE_X86_MMX;   break;
932     case Type::X86_AMXTyID:   Code = bitc::TYPE_CODE_X86_AMX;   break;
933     case Type::TokenTyID:     Code = bitc::TYPE_CODE_TOKEN;     break;
934     case Type::IntegerTyID:
935       // INTEGER: [width]
936       Code = bitc::TYPE_CODE_INTEGER;
937       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
938       break;
939     case Type::PointerTyID: {
940       PointerType *PTy = cast<PointerType>(T);
941       unsigned AddressSpace = PTy->getAddressSpace();
942       if (PTy->isOpaque()) {
943         // OPAQUE_POINTER: [address space]
944         Code = bitc::TYPE_CODE_OPAQUE_POINTER;
945         TypeVals.push_back(AddressSpace);
946         if (AddressSpace == 0)
947           AbbrevToUse = OpaquePtrAbbrev;
948       } else {
949         // POINTER: [pointee type, address space]
950         Code = bitc::TYPE_CODE_POINTER;
951         TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
952         TypeVals.push_back(AddressSpace);
953         if (AddressSpace == 0)
954           AbbrevToUse = PtrAbbrev;
955       }
956       break;
957     }
958     case Type::FunctionTyID: {
959       FunctionType *FT = cast<FunctionType>(T);
960       // FUNCTION: [isvararg, retty, paramty x N]
961       Code = bitc::TYPE_CODE_FUNCTION;
962       TypeVals.push_back(FT->isVarArg());
963       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
964       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
965         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
966       AbbrevToUse = FunctionAbbrev;
967       break;
968     }
969     case Type::StructTyID: {
970       StructType *ST = cast<StructType>(T);
971       // STRUCT: [ispacked, eltty x N]
972       TypeVals.push_back(ST->isPacked());
973       // Output all of the element types.
974       for (Type *ET : ST->elements())
975         TypeVals.push_back(VE.getTypeID(ET));
976 
977       if (ST->isLiteral()) {
978         Code = bitc::TYPE_CODE_STRUCT_ANON;
979         AbbrevToUse = StructAnonAbbrev;
980       } else {
981         if (ST->isOpaque()) {
982           Code = bitc::TYPE_CODE_OPAQUE;
983         } else {
984           Code = bitc::TYPE_CODE_STRUCT_NAMED;
985           AbbrevToUse = StructNamedAbbrev;
986         }
987 
988         // Emit the name if it is present.
989         if (!ST->getName().empty())
990           writeStringRecord(Stream, bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
991                             StructNameAbbrev);
992       }
993       break;
994     }
995     case Type::ArrayTyID: {
996       ArrayType *AT = cast<ArrayType>(T);
997       // ARRAY: [numelts, eltty]
998       Code = bitc::TYPE_CODE_ARRAY;
999       TypeVals.push_back(AT->getNumElements());
1000       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
1001       AbbrevToUse = ArrayAbbrev;
1002       break;
1003     }
1004     case Type::FixedVectorTyID:
1005     case Type::ScalableVectorTyID: {
1006       VectorType *VT = cast<VectorType>(T);
1007       // VECTOR [numelts, eltty] or
1008       //        [numelts, eltty, scalable]
1009       Code = bitc::TYPE_CODE_VECTOR;
1010       TypeVals.push_back(VT->getElementCount().getKnownMinValue());
1011       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
1012       if (isa<ScalableVectorType>(VT))
1013         TypeVals.push_back(true);
1014       break;
1015     }
1016     }
1017 
1018     // Emit the finished record.
1019     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
1020     TypeVals.clear();
1021   }
1022 
1023   Stream.ExitBlock();
1024 }
1025 
1026 static unsigned getEncodedLinkage(const GlobalValue::LinkageTypes Linkage) {
1027   switch (Linkage) {
1028   case GlobalValue::ExternalLinkage:
1029     return 0;
1030   case GlobalValue::WeakAnyLinkage:
1031     return 16;
1032   case GlobalValue::AppendingLinkage:
1033     return 2;
1034   case GlobalValue::InternalLinkage:
1035     return 3;
1036   case GlobalValue::LinkOnceAnyLinkage:
1037     return 18;
1038   case GlobalValue::ExternalWeakLinkage:
1039     return 7;
1040   case GlobalValue::CommonLinkage:
1041     return 8;
1042   case GlobalValue::PrivateLinkage:
1043     return 9;
1044   case GlobalValue::WeakODRLinkage:
1045     return 17;
1046   case GlobalValue::LinkOnceODRLinkage:
1047     return 19;
1048   case GlobalValue::AvailableExternallyLinkage:
1049     return 12;
1050   }
1051   llvm_unreachable("Invalid linkage");
1052 }
1053 
1054 static unsigned getEncodedLinkage(const GlobalValue &GV) {
1055   return getEncodedLinkage(GV.getLinkage());
1056 }
1057 
1058 static uint64_t getEncodedFFlags(FunctionSummary::FFlags Flags) {
1059   uint64_t RawFlags = 0;
1060   RawFlags |= Flags.ReadNone;
1061   RawFlags |= (Flags.ReadOnly << 1);
1062   RawFlags |= (Flags.NoRecurse << 2);
1063   RawFlags |= (Flags.ReturnDoesNotAlias << 3);
1064   RawFlags |= (Flags.NoInline << 4);
1065   RawFlags |= (Flags.AlwaysInline << 5);
1066   RawFlags |= (Flags.NoUnwind << 6);
1067   RawFlags |= (Flags.MayThrow << 7);
1068   RawFlags |= (Flags.HasUnknownCall << 8);
1069   RawFlags |= (Flags.MustBeUnreachable << 9);
1070   return RawFlags;
1071 }
1072 
1073 // Decode the flags for GlobalValue in the summary. See getDecodedGVSummaryFlags
1074 // in BitcodeReader.cpp.
1075 static uint64_t getEncodedGVSummaryFlags(GlobalValueSummary::GVFlags Flags) {
1076   uint64_t RawFlags = 0;
1077 
1078   RawFlags |= Flags.NotEligibleToImport; // bool
1079   RawFlags |= (Flags.Live << 1);
1080   RawFlags |= (Flags.DSOLocal << 2);
1081   RawFlags |= (Flags.CanAutoHide << 3);
1082 
1083   // Linkage don't need to be remapped at that time for the summary. Any future
1084   // change to the getEncodedLinkage() function will need to be taken into
1085   // account here as well.
1086   RawFlags = (RawFlags << 4) | Flags.Linkage; // 4 bits
1087 
1088   RawFlags |= (Flags.Visibility << 8); // 2 bits
1089 
1090   return RawFlags;
1091 }
1092 
1093 static uint64_t getEncodedGVarFlags(GlobalVarSummary::GVarFlags Flags) {
1094   uint64_t RawFlags = Flags.MaybeReadOnly | (Flags.MaybeWriteOnly << 1) |
1095                       (Flags.Constant << 2) | Flags.VCallVisibility << 3;
1096   return RawFlags;
1097 }
1098 
1099 static unsigned getEncodedVisibility(const GlobalValue &GV) {
1100   switch (GV.getVisibility()) {
1101   case GlobalValue::DefaultVisibility:   return 0;
1102   case GlobalValue::HiddenVisibility:    return 1;
1103   case GlobalValue::ProtectedVisibility: return 2;
1104   }
1105   llvm_unreachable("Invalid visibility");
1106 }
1107 
1108 static unsigned getEncodedDLLStorageClass(const GlobalValue &GV) {
1109   switch (GV.getDLLStorageClass()) {
1110   case GlobalValue::DefaultStorageClass:   return 0;
1111   case GlobalValue::DLLImportStorageClass: return 1;
1112   case GlobalValue::DLLExportStorageClass: return 2;
1113   }
1114   llvm_unreachable("Invalid DLL storage class");
1115 }
1116 
1117 static unsigned getEncodedThreadLocalMode(const GlobalValue &GV) {
1118   switch (GV.getThreadLocalMode()) {
1119     case GlobalVariable::NotThreadLocal:         return 0;
1120     case GlobalVariable::GeneralDynamicTLSModel: return 1;
1121     case GlobalVariable::LocalDynamicTLSModel:   return 2;
1122     case GlobalVariable::InitialExecTLSModel:    return 3;
1123     case GlobalVariable::LocalExecTLSModel:      return 4;
1124   }
1125   llvm_unreachable("Invalid TLS model");
1126 }
1127 
1128 static unsigned getEncodedComdatSelectionKind(const Comdat &C) {
1129   switch (C.getSelectionKind()) {
1130   case Comdat::Any:
1131     return bitc::COMDAT_SELECTION_KIND_ANY;
1132   case Comdat::ExactMatch:
1133     return bitc::COMDAT_SELECTION_KIND_EXACT_MATCH;
1134   case Comdat::Largest:
1135     return bitc::COMDAT_SELECTION_KIND_LARGEST;
1136   case Comdat::NoDeduplicate:
1137     return bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES;
1138   case Comdat::SameSize:
1139     return bitc::COMDAT_SELECTION_KIND_SAME_SIZE;
1140   }
1141   llvm_unreachable("Invalid selection kind");
1142 }
1143 
1144 static unsigned getEncodedUnnamedAddr(const GlobalValue &GV) {
1145   switch (GV.getUnnamedAddr()) {
1146   case GlobalValue::UnnamedAddr::None:   return 0;
1147   case GlobalValue::UnnamedAddr::Local:  return 2;
1148   case GlobalValue::UnnamedAddr::Global: return 1;
1149   }
1150   llvm_unreachable("Invalid unnamed_addr");
1151 }
1152 
1153 size_t ModuleBitcodeWriter::addToStrtab(StringRef Str) {
1154   if (GenerateHash)
1155     Hasher.update(Str);
1156   return StrtabBuilder.add(Str);
1157 }
1158 
1159 void ModuleBitcodeWriter::writeComdats() {
1160   SmallVector<unsigned, 64> Vals;
1161   for (const Comdat *C : VE.getComdats()) {
1162     // COMDAT: [strtab offset, strtab size, selection_kind]
1163     Vals.push_back(addToStrtab(C->getName()));
1164     Vals.push_back(C->getName().size());
1165     Vals.push_back(getEncodedComdatSelectionKind(*C));
1166     Stream.EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
1167     Vals.clear();
1168   }
1169 }
1170 
1171 /// Write a record that will eventually hold the word offset of the
1172 /// module-level VST. For now the offset is 0, which will be backpatched
1173 /// after the real VST is written. Saves the bit offset to backpatch.
1174 void ModuleBitcodeWriter::writeValueSymbolTableForwardDecl() {
1175   // Write a placeholder value in for the offset of the real VST,
1176   // which is written after the function blocks so that it can include
1177   // the offset of each function. The placeholder offset will be
1178   // updated when the real VST is written.
1179   auto Abbv = std::make_shared<BitCodeAbbrev>();
1180   Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_VSTOFFSET));
1181   // Blocks are 32-bit aligned, so we can use a 32-bit word offset to
1182   // hold the real VST offset. Must use fixed instead of VBR as we don't
1183   // know how many VBR chunks to reserve ahead of time.
1184   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
1185   unsigned VSTOffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1186 
1187   // Emit the placeholder
1188   uint64_t Vals[] = {bitc::MODULE_CODE_VSTOFFSET, 0};
1189   Stream.EmitRecordWithAbbrev(VSTOffsetAbbrev, Vals);
1190 
1191   // Compute and save the bit offset to the placeholder, which will be
1192   // patched when the real VST is written. We can simply subtract the 32-bit
1193   // fixed size from the current bit number to get the location to backpatch.
1194   VSTOffsetPlaceholder = Stream.GetCurrentBitNo() - 32;
1195 }
1196 
1197 enum StringEncoding { SE_Char6, SE_Fixed7, SE_Fixed8 };
1198 
1199 /// Determine the encoding to use for the given string name and length.
1200 static StringEncoding getStringEncoding(StringRef Str) {
1201   bool isChar6 = true;
1202   for (char C : Str) {
1203     if (isChar6)
1204       isChar6 = BitCodeAbbrevOp::isChar6(C);
1205     if ((unsigned char)C & 128)
1206       // don't bother scanning the rest.
1207       return SE_Fixed8;
1208   }
1209   if (isChar6)
1210     return SE_Char6;
1211   return SE_Fixed7;
1212 }
1213 
1214 /// Emit top-level description of module, including target triple, inline asm,
1215 /// descriptors for global variables, and function prototype info.
1216 /// Returns the bit offset to backpatch with the location of the real VST.
1217 void ModuleBitcodeWriter::writeModuleInfo() {
1218   // Emit various pieces of data attached to a module.
1219   if (!M.getTargetTriple().empty())
1220     writeStringRecord(Stream, bitc::MODULE_CODE_TRIPLE, M.getTargetTriple(),
1221                       0 /*TODO*/);
1222   const std::string &DL = M.getDataLayoutStr();
1223   if (!DL.empty())
1224     writeStringRecord(Stream, bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/);
1225   if (!M.getModuleInlineAsm().empty())
1226     writeStringRecord(Stream, bitc::MODULE_CODE_ASM, M.getModuleInlineAsm(),
1227                       0 /*TODO*/);
1228 
1229   // Emit information about sections and GC, computing how many there are. Also
1230   // compute the maximum alignment value.
1231   std::map<std::string, unsigned> SectionMap;
1232   std::map<std::string, unsigned> GCMap;
1233   MaybeAlign MaxAlignment;
1234   unsigned MaxGlobalType = 0;
1235   const auto UpdateMaxAlignment = [&MaxAlignment](const MaybeAlign A) {
1236     if (A)
1237       MaxAlignment = !MaxAlignment ? *A : std::max(*MaxAlignment, *A);
1238   };
1239   for (const GlobalVariable &GV : M.globals()) {
1240     UpdateMaxAlignment(GV.getAlign());
1241     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getValueType()));
1242     if (GV.hasSection()) {
1243       // Give section names unique ID's.
1244       unsigned &Entry = SectionMap[std::string(GV.getSection())];
1245       if (!Entry) {
1246         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
1247                           0 /*TODO*/);
1248         Entry = SectionMap.size();
1249       }
1250     }
1251   }
1252   for (const Function &F : M) {
1253     UpdateMaxAlignment(F.getAlign());
1254     if (F.hasSection()) {
1255       // Give section names unique ID's.
1256       unsigned &Entry = SectionMap[std::string(F.getSection())];
1257       if (!Entry) {
1258         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
1259                           0 /*TODO*/);
1260         Entry = SectionMap.size();
1261       }
1262     }
1263     if (F.hasGC()) {
1264       // Same for GC names.
1265       unsigned &Entry = GCMap[F.getGC()];
1266       if (!Entry) {
1267         writeStringRecord(Stream, bitc::MODULE_CODE_GCNAME, F.getGC(),
1268                           0 /*TODO*/);
1269         Entry = GCMap.size();
1270       }
1271     }
1272   }
1273 
1274   // Emit abbrev for globals, now that we know # sections and max alignment.
1275   unsigned SimpleGVarAbbrev = 0;
1276   if (!M.global_empty()) {
1277     // Add an abbrev for common globals with no visibility or thread localness.
1278     auto Abbv = std::make_shared<BitCodeAbbrev>();
1279     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
1280     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1281     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1282     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1283                               Log2_32_Ceil(MaxGlobalType+1)));
1284     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddrSpace << 2
1285                                                            //| explicitType << 1
1286                                                            //| constant
1287     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Initializer.
1288     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // Linkage.
1289     if (!MaxAlignment)                                     // Alignment.
1290       Abbv->Add(BitCodeAbbrevOp(0));
1291     else {
1292       unsigned MaxEncAlignment = getEncodedAlign(MaxAlignment);
1293       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1294                                Log2_32_Ceil(MaxEncAlignment+1)));
1295     }
1296     if (SectionMap.empty())                                    // Section.
1297       Abbv->Add(BitCodeAbbrevOp(0));
1298     else
1299       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1300                                Log2_32_Ceil(SectionMap.size()+1)));
1301     // Don't bother emitting vis + thread local.
1302     SimpleGVarAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1303   }
1304 
1305   SmallVector<unsigned, 64> Vals;
1306   // Emit the module's source file name.
1307   {
1308     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
1309     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
1310     if (Bits == SE_Char6)
1311       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
1312     else if (Bits == SE_Fixed7)
1313       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
1314 
1315     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
1316     auto Abbv = std::make_shared<BitCodeAbbrev>();
1317     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
1318     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1319     Abbv->Add(AbbrevOpToUse);
1320     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1321 
1322     for (const auto P : M.getSourceFileName())
1323       Vals.push_back((unsigned char)P);
1324 
1325     // Emit the finished record.
1326     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
1327     Vals.clear();
1328   }
1329 
1330   // Emit the global variable information.
1331   for (const GlobalVariable &GV : M.globals()) {
1332     unsigned AbbrevToUse = 0;
1333 
1334     // GLOBALVAR: [strtab offset, strtab size, type, isconst, initid,
1335     //             linkage, alignment, section, visibility, threadlocal,
1336     //             unnamed_addr, externally_initialized, dllstorageclass,
1337     //             comdat, attributes, DSO_Local]
1338     Vals.push_back(addToStrtab(GV.getName()));
1339     Vals.push_back(GV.getName().size());
1340     Vals.push_back(VE.getTypeID(GV.getValueType()));
1341     Vals.push_back(GV.getType()->getAddressSpace() << 2 | 2 | GV.isConstant());
1342     Vals.push_back(GV.isDeclaration() ? 0 :
1343                    (VE.getValueID(GV.getInitializer()) + 1));
1344     Vals.push_back(getEncodedLinkage(GV));
1345     Vals.push_back(getEncodedAlign(GV.getAlign()));
1346     Vals.push_back(GV.hasSection() ? SectionMap[std::string(GV.getSection())]
1347                                    : 0);
1348     if (GV.isThreadLocal() ||
1349         GV.getVisibility() != GlobalValue::DefaultVisibility ||
1350         GV.getUnnamedAddr() != GlobalValue::UnnamedAddr::None ||
1351         GV.isExternallyInitialized() ||
1352         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
1353         GV.hasComdat() ||
1354         GV.hasAttributes() ||
1355         GV.isDSOLocal() ||
1356         GV.hasPartition()) {
1357       Vals.push_back(getEncodedVisibility(GV));
1358       Vals.push_back(getEncodedThreadLocalMode(GV));
1359       Vals.push_back(getEncodedUnnamedAddr(GV));
1360       Vals.push_back(GV.isExternallyInitialized());
1361       Vals.push_back(getEncodedDLLStorageClass(GV));
1362       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
1363 
1364       auto AL = GV.getAttributesAsList(AttributeList::FunctionIndex);
1365       Vals.push_back(VE.getAttributeListID(AL));
1366 
1367       Vals.push_back(GV.isDSOLocal());
1368       Vals.push_back(addToStrtab(GV.getPartition()));
1369       Vals.push_back(GV.getPartition().size());
1370     } else {
1371       AbbrevToUse = SimpleGVarAbbrev;
1372     }
1373 
1374     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
1375     Vals.clear();
1376   }
1377 
1378   // Emit the function proto information.
1379   for (const Function &F : M) {
1380     // FUNCTION:  [strtab offset, strtab size, type, callingconv, isproto,
1381     //             linkage, paramattrs, alignment, section, visibility, gc,
1382     //             unnamed_addr, prologuedata, dllstorageclass, comdat,
1383     //             prefixdata, personalityfn, DSO_Local, addrspace]
1384     Vals.push_back(addToStrtab(F.getName()));
1385     Vals.push_back(F.getName().size());
1386     Vals.push_back(VE.getTypeID(F.getFunctionType()));
1387     Vals.push_back(F.getCallingConv());
1388     Vals.push_back(F.isDeclaration());
1389     Vals.push_back(getEncodedLinkage(F));
1390     Vals.push_back(VE.getAttributeListID(F.getAttributes()));
1391     Vals.push_back(getEncodedAlign(F.getAlign()));
1392     Vals.push_back(F.hasSection() ? SectionMap[std::string(F.getSection())]
1393                                   : 0);
1394     Vals.push_back(getEncodedVisibility(F));
1395     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
1396     Vals.push_back(getEncodedUnnamedAddr(F));
1397     Vals.push_back(F.hasPrologueData() ? (VE.getValueID(F.getPrologueData()) + 1)
1398                                        : 0);
1399     Vals.push_back(getEncodedDLLStorageClass(F));
1400     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
1401     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
1402                                      : 0);
1403     Vals.push_back(
1404         F.hasPersonalityFn() ? (VE.getValueID(F.getPersonalityFn()) + 1) : 0);
1405 
1406     Vals.push_back(F.isDSOLocal());
1407     Vals.push_back(F.getAddressSpace());
1408     Vals.push_back(addToStrtab(F.getPartition()));
1409     Vals.push_back(F.getPartition().size());
1410 
1411     unsigned AbbrevToUse = 0;
1412     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
1413     Vals.clear();
1414   }
1415 
1416   // Emit the alias information.
1417   for (const GlobalAlias &A : M.aliases()) {
1418     // ALIAS: [strtab offset, strtab size, alias type, aliasee val#, linkage,
1419     //         visibility, dllstorageclass, threadlocal, unnamed_addr,
1420     //         DSO_Local]
1421     Vals.push_back(addToStrtab(A.getName()));
1422     Vals.push_back(A.getName().size());
1423     Vals.push_back(VE.getTypeID(A.getValueType()));
1424     Vals.push_back(A.getType()->getAddressSpace());
1425     Vals.push_back(VE.getValueID(A.getAliasee()));
1426     Vals.push_back(getEncodedLinkage(A));
1427     Vals.push_back(getEncodedVisibility(A));
1428     Vals.push_back(getEncodedDLLStorageClass(A));
1429     Vals.push_back(getEncodedThreadLocalMode(A));
1430     Vals.push_back(getEncodedUnnamedAddr(A));
1431     Vals.push_back(A.isDSOLocal());
1432     Vals.push_back(addToStrtab(A.getPartition()));
1433     Vals.push_back(A.getPartition().size());
1434 
1435     unsigned AbbrevToUse = 0;
1436     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
1437     Vals.clear();
1438   }
1439 
1440   // Emit the ifunc information.
1441   for (const GlobalIFunc &I : M.ifuncs()) {
1442     // IFUNC: [strtab offset, strtab size, ifunc type, address space, resolver
1443     //         val#, linkage, visibility, DSO_Local]
1444     Vals.push_back(addToStrtab(I.getName()));
1445     Vals.push_back(I.getName().size());
1446     Vals.push_back(VE.getTypeID(I.getValueType()));
1447     Vals.push_back(I.getType()->getAddressSpace());
1448     Vals.push_back(VE.getValueID(I.getResolver()));
1449     Vals.push_back(getEncodedLinkage(I));
1450     Vals.push_back(getEncodedVisibility(I));
1451     Vals.push_back(I.isDSOLocal());
1452     Vals.push_back(addToStrtab(I.getPartition()));
1453     Vals.push_back(I.getPartition().size());
1454     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
1455     Vals.clear();
1456   }
1457 
1458   writeValueSymbolTableForwardDecl();
1459 }
1460 
1461 static uint64_t getOptimizationFlags(const Value *V) {
1462   uint64_t Flags = 0;
1463 
1464   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
1465     if (OBO->hasNoSignedWrap())
1466       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
1467     if (OBO->hasNoUnsignedWrap())
1468       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
1469   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
1470     if (PEO->isExact())
1471       Flags |= 1 << bitc::PEO_EXACT;
1472   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
1473     if (FPMO->hasAllowReassoc())
1474       Flags |= bitc::AllowReassoc;
1475     if (FPMO->hasNoNaNs())
1476       Flags |= bitc::NoNaNs;
1477     if (FPMO->hasNoInfs())
1478       Flags |= bitc::NoInfs;
1479     if (FPMO->hasNoSignedZeros())
1480       Flags |= bitc::NoSignedZeros;
1481     if (FPMO->hasAllowReciprocal())
1482       Flags |= bitc::AllowReciprocal;
1483     if (FPMO->hasAllowContract())
1484       Flags |= bitc::AllowContract;
1485     if (FPMO->hasApproxFunc())
1486       Flags |= bitc::ApproxFunc;
1487   }
1488 
1489   return Flags;
1490 }
1491 
1492 void ModuleBitcodeWriter::writeValueAsMetadata(
1493     const ValueAsMetadata *MD, SmallVectorImpl<uint64_t> &Record) {
1494   // Mimic an MDNode with a value as one operand.
1495   Value *V = MD->getValue();
1496   Record.push_back(VE.getTypeID(V->getType()));
1497   Record.push_back(VE.getValueID(V));
1498   Stream.EmitRecord(bitc::METADATA_VALUE, Record, 0);
1499   Record.clear();
1500 }
1501 
1502 void ModuleBitcodeWriter::writeMDTuple(const MDTuple *N,
1503                                        SmallVectorImpl<uint64_t> &Record,
1504                                        unsigned Abbrev) {
1505   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
1506     Metadata *MD = N->getOperand(i);
1507     assert(!(MD && isa<LocalAsMetadata>(MD)) &&
1508            "Unexpected function-local metadata");
1509     Record.push_back(VE.getMetadataOrNullID(MD));
1510   }
1511   Stream.EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
1512                                     : bitc::METADATA_NODE,
1513                     Record, Abbrev);
1514   Record.clear();
1515 }
1516 
1517 unsigned ModuleBitcodeWriter::createDILocationAbbrev() {
1518   // Assume the column is usually under 128, and always output the inlined-at
1519   // location (it's never more expensive than building an array size 1).
1520   auto Abbv = std::make_shared<BitCodeAbbrev>();
1521   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
1522   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1523   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1524   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1525   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1526   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1527   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1528   return Stream.EmitAbbrev(std::move(Abbv));
1529 }
1530 
1531 void ModuleBitcodeWriter::writeDILocation(const DILocation *N,
1532                                           SmallVectorImpl<uint64_t> &Record,
1533                                           unsigned &Abbrev) {
1534   if (!Abbrev)
1535     Abbrev = createDILocationAbbrev();
1536 
1537   Record.push_back(N->isDistinct());
1538   Record.push_back(N->getLine());
1539   Record.push_back(N->getColumn());
1540   Record.push_back(VE.getMetadataID(N->getScope()));
1541   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
1542   Record.push_back(N->isImplicitCode());
1543 
1544   Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
1545   Record.clear();
1546 }
1547 
1548 unsigned ModuleBitcodeWriter::createGenericDINodeAbbrev() {
1549   // Assume the column is usually under 128, and always output the inlined-at
1550   // location (it's never more expensive than building an array size 1).
1551   auto Abbv = std::make_shared<BitCodeAbbrev>();
1552   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
1553   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1554   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1555   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1556   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1557   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1558   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1559   return Stream.EmitAbbrev(std::move(Abbv));
1560 }
1561 
1562 void ModuleBitcodeWriter::writeGenericDINode(const GenericDINode *N,
1563                                              SmallVectorImpl<uint64_t> &Record,
1564                                              unsigned &Abbrev) {
1565   if (!Abbrev)
1566     Abbrev = createGenericDINodeAbbrev();
1567 
1568   Record.push_back(N->isDistinct());
1569   Record.push_back(N->getTag());
1570   Record.push_back(0); // Per-tag version field; unused for now.
1571 
1572   for (auto &I : N->operands())
1573     Record.push_back(VE.getMetadataOrNullID(I));
1574 
1575   Stream.EmitRecord(bitc::METADATA_GENERIC_DEBUG, Record, Abbrev);
1576   Record.clear();
1577 }
1578 
1579 void ModuleBitcodeWriter::writeDISubrange(const DISubrange *N,
1580                                           SmallVectorImpl<uint64_t> &Record,
1581                                           unsigned Abbrev) {
1582   const uint64_t Version = 2 << 1;
1583   Record.push_back((uint64_t)N->isDistinct() | Version);
1584   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1585   Record.push_back(VE.getMetadataOrNullID(N->getRawLowerBound()));
1586   Record.push_back(VE.getMetadataOrNullID(N->getRawUpperBound()));
1587   Record.push_back(VE.getMetadataOrNullID(N->getRawStride()));
1588 
1589   Stream.EmitRecord(bitc::METADATA_SUBRANGE, Record, Abbrev);
1590   Record.clear();
1591 }
1592 
1593 void ModuleBitcodeWriter::writeDIGenericSubrange(
1594     const DIGenericSubrange *N, SmallVectorImpl<uint64_t> &Record,
1595     unsigned Abbrev) {
1596   Record.push_back((uint64_t)N->isDistinct());
1597   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1598   Record.push_back(VE.getMetadataOrNullID(N->getRawLowerBound()));
1599   Record.push_back(VE.getMetadataOrNullID(N->getRawUpperBound()));
1600   Record.push_back(VE.getMetadataOrNullID(N->getRawStride()));
1601 
1602   Stream.EmitRecord(bitc::METADATA_GENERIC_SUBRANGE, Record, Abbrev);
1603   Record.clear();
1604 }
1605 
1606 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
1607   if ((int64_t)V >= 0)
1608     Vals.push_back(V << 1);
1609   else
1610     Vals.push_back((-V << 1) | 1);
1611 }
1612 
1613 static void emitWideAPInt(SmallVectorImpl<uint64_t> &Vals, const APInt &A) {
1614   // We have an arbitrary precision integer value to write whose
1615   // bit width is > 64. However, in canonical unsigned integer
1616   // format it is likely that the high bits are going to be zero.
1617   // So, we only write the number of active words.
1618   unsigned NumWords = A.getActiveWords();
1619   const uint64_t *RawData = A.getRawData();
1620   for (unsigned i = 0; i < NumWords; i++)
1621     emitSignedInt64(Vals, RawData[i]);
1622 }
1623 
1624 void ModuleBitcodeWriter::writeDIEnumerator(const DIEnumerator *N,
1625                                             SmallVectorImpl<uint64_t> &Record,
1626                                             unsigned Abbrev) {
1627   const uint64_t IsBigInt = 1 << 2;
1628   Record.push_back(IsBigInt | (N->isUnsigned() << 1) | N->isDistinct());
1629   Record.push_back(N->getValue().getBitWidth());
1630   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1631   emitWideAPInt(Record, N->getValue());
1632 
1633   Stream.EmitRecord(bitc::METADATA_ENUMERATOR, Record, Abbrev);
1634   Record.clear();
1635 }
1636 
1637 void ModuleBitcodeWriter::writeDIBasicType(const DIBasicType *N,
1638                                            SmallVectorImpl<uint64_t> &Record,
1639                                            unsigned Abbrev) {
1640   Record.push_back(N->isDistinct());
1641   Record.push_back(N->getTag());
1642   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1643   Record.push_back(N->getSizeInBits());
1644   Record.push_back(N->getAlignInBits());
1645   Record.push_back(N->getEncoding());
1646   Record.push_back(N->getFlags());
1647 
1648   Stream.EmitRecord(bitc::METADATA_BASIC_TYPE, Record, Abbrev);
1649   Record.clear();
1650 }
1651 
1652 void ModuleBitcodeWriter::writeDIStringType(const DIStringType *N,
1653                                             SmallVectorImpl<uint64_t> &Record,
1654                                             unsigned Abbrev) {
1655   Record.push_back(N->isDistinct());
1656   Record.push_back(N->getTag());
1657   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1658   Record.push_back(VE.getMetadataOrNullID(N->getStringLength()));
1659   Record.push_back(VE.getMetadataOrNullID(N->getStringLengthExp()));
1660   Record.push_back(N->getSizeInBits());
1661   Record.push_back(N->getAlignInBits());
1662   Record.push_back(N->getEncoding());
1663 
1664   Stream.EmitRecord(bitc::METADATA_STRING_TYPE, Record, Abbrev);
1665   Record.clear();
1666 }
1667 
1668 void ModuleBitcodeWriter::writeDIDerivedType(const DIDerivedType *N,
1669                                              SmallVectorImpl<uint64_t> &Record,
1670                                              unsigned Abbrev) {
1671   Record.push_back(N->isDistinct());
1672   Record.push_back(N->getTag());
1673   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1674   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1675   Record.push_back(N->getLine());
1676   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1677   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1678   Record.push_back(N->getSizeInBits());
1679   Record.push_back(N->getAlignInBits());
1680   Record.push_back(N->getOffsetInBits());
1681   Record.push_back(N->getFlags());
1682   Record.push_back(VE.getMetadataOrNullID(N->getExtraData()));
1683 
1684   // DWARF address space is encoded as N->getDWARFAddressSpace() + 1. 0 means
1685   // that there is no DWARF address space associated with DIDerivedType.
1686   if (const auto &DWARFAddressSpace = N->getDWARFAddressSpace())
1687     Record.push_back(*DWARFAddressSpace + 1);
1688   else
1689     Record.push_back(0);
1690 
1691   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1692 
1693   Stream.EmitRecord(bitc::METADATA_DERIVED_TYPE, Record, Abbrev);
1694   Record.clear();
1695 }
1696 
1697 void ModuleBitcodeWriter::writeDICompositeType(
1698     const DICompositeType *N, SmallVectorImpl<uint64_t> &Record,
1699     unsigned Abbrev) {
1700   const unsigned IsNotUsedInOldTypeRef = 0x2;
1701   Record.push_back(IsNotUsedInOldTypeRef | (unsigned)N->isDistinct());
1702   Record.push_back(N->getTag());
1703   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1704   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1705   Record.push_back(N->getLine());
1706   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1707   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1708   Record.push_back(N->getSizeInBits());
1709   Record.push_back(N->getAlignInBits());
1710   Record.push_back(N->getOffsetInBits());
1711   Record.push_back(N->getFlags());
1712   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1713   Record.push_back(N->getRuntimeLang());
1714   Record.push_back(VE.getMetadataOrNullID(N->getVTableHolder()));
1715   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1716   Record.push_back(VE.getMetadataOrNullID(N->getRawIdentifier()));
1717   Record.push_back(VE.getMetadataOrNullID(N->getDiscriminator()));
1718   Record.push_back(VE.getMetadataOrNullID(N->getRawDataLocation()));
1719   Record.push_back(VE.getMetadataOrNullID(N->getRawAssociated()));
1720   Record.push_back(VE.getMetadataOrNullID(N->getRawAllocated()));
1721   Record.push_back(VE.getMetadataOrNullID(N->getRawRank()));
1722   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1723 
1724   Stream.EmitRecord(bitc::METADATA_COMPOSITE_TYPE, Record, Abbrev);
1725   Record.clear();
1726 }
1727 
1728 void ModuleBitcodeWriter::writeDISubroutineType(
1729     const DISubroutineType *N, SmallVectorImpl<uint64_t> &Record,
1730     unsigned Abbrev) {
1731   const unsigned HasNoOldTypeRefs = 0x2;
1732   Record.push_back(HasNoOldTypeRefs | (unsigned)N->isDistinct());
1733   Record.push_back(N->getFlags());
1734   Record.push_back(VE.getMetadataOrNullID(N->getTypeArray().get()));
1735   Record.push_back(N->getCC());
1736 
1737   Stream.EmitRecord(bitc::METADATA_SUBROUTINE_TYPE, Record, Abbrev);
1738   Record.clear();
1739 }
1740 
1741 void ModuleBitcodeWriter::writeDIFile(const DIFile *N,
1742                                       SmallVectorImpl<uint64_t> &Record,
1743                                       unsigned Abbrev) {
1744   Record.push_back(N->isDistinct());
1745   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
1746   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
1747   if (N->getRawChecksum()) {
1748     Record.push_back(N->getRawChecksum()->Kind);
1749     Record.push_back(VE.getMetadataOrNullID(N->getRawChecksum()->Value));
1750   } else {
1751     // Maintain backwards compatibility with the old internal representation of
1752     // CSK_None in ChecksumKind by writing nulls here when Checksum is None.
1753     Record.push_back(0);
1754     Record.push_back(VE.getMetadataOrNullID(nullptr));
1755   }
1756   auto Source = N->getRawSource();
1757   if (Source)
1758     Record.push_back(VE.getMetadataOrNullID(*Source));
1759 
1760   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
1761   Record.clear();
1762 }
1763 
1764 void ModuleBitcodeWriter::writeDICompileUnit(const DICompileUnit *N,
1765                                              SmallVectorImpl<uint64_t> &Record,
1766                                              unsigned Abbrev) {
1767   assert(N->isDistinct() && "Expected distinct compile units");
1768   Record.push_back(/* IsDistinct */ true);
1769   Record.push_back(N->getSourceLanguage());
1770   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1771   Record.push_back(VE.getMetadataOrNullID(N->getRawProducer()));
1772   Record.push_back(N->isOptimized());
1773   Record.push_back(VE.getMetadataOrNullID(N->getRawFlags()));
1774   Record.push_back(N->getRuntimeVersion());
1775   Record.push_back(VE.getMetadataOrNullID(N->getRawSplitDebugFilename()));
1776   Record.push_back(N->getEmissionKind());
1777   Record.push_back(VE.getMetadataOrNullID(N->getEnumTypes().get()));
1778   Record.push_back(VE.getMetadataOrNullID(N->getRetainedTypes().get()));
1779   Record.push_back(/* subprograms */ 0);
1780   Record.push_back(VE.getMetadataOrNullID(N->getGlobalVariables().get()));
1781   Record.push_back(VE.getMetadataOrNullID(N->getImportedEntities().get()));
1782   Record.push_back(N->getDWOId());
1783   Record.push_back(VE.getMetadataOrNullID(N->getMacros().get()));
1784   Record.push_back(N->getSplitDebugInlining());
1785   Record.push_back(N->getDebugInfoForProfiling());
1786   Record.push_back((unsigned)N->getNameTableKind());
1787   Record.push_back(N->getRangesBaseAddress());
1788   Record.push_back(VE.getMetadataOrNullID(N->getRawSysRoot()));
1789   Record.push_back(VE.getMetadataOrNullID(N->getRawSDK()));
1790 
1791   Stream.EmitRecord(bitc::METADATA_COMPILE_UNIT, Record, Abbrev);
1792   Record.clear();
1793 }
1794 
1795 void ModuleBitcodeWriter::writeDISubprogram(const DISubprogram *N,
1796                                             SmallVectorImpl<uint64_t> &Record,
1797                                             unsigned Abbrev) {
1798   const uint64_t HasUnitFlag = 1 << 1;
1799   const uint64_t HasSPFlagsFlag = 1 << 2;
1800   Record.push_back(uint64_t(N->isDistinct()) | HasUnitFlag | HasSPFlagsFlag);
1801   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1802   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1803   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1804   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1805   Record.push_back(N->getLine());
1806   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1807   Record.push_back(N->getScopeLine());
1808   Record.push_back(VE.getMetadataOrNullID(N->getContainingType()));
1809   Record.push_back(N->getSPFlags());
1810   Record.push_back(N->getVirtualIndex());
1811   Record.push_back(N->getFlags());
1812   Record.push_back(VE.getMetadataOrNullID(N->getRawUnit()));
1813   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1814   Record.push_back(VE.getMetadataOrNullID(N->getDeclaration()));
1815   Record.push_back(VE.getMetadataOrNullID(N->getRetainedNodes().get()));
1816   Record.push_back(N->getThisAdjustment());
1817   Record.push_back(VE.getMetadataOrNullID(N->getThrownTypes().get()));
1818   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1819 
1820   Stream.EmitRecord(bitc::METADATA_SUBPROGRAM, Record, Abbrev);
1821   Record.clear();
1822 }
1823 
1824 void ModuleBitcodeWriter::writeDILexicalBlock(const DILexicalBlock *N,
1825                                               SmallVectorImpl<uint64_t> &Record,
1826                                               unsigned Abbrev) {
1827   Record.push_back(N->isDistinct());
1828   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1829   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1830   Record.push_back(N->getLine());
1831   Record.push_back(N->getColumn());
1832 
1833   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK, Record, Abbrev);
1834   Record.clear();
1835 }
1836 
1837 void ModuleBitcodeWriter::writeDILexicalBlockFile(
1838     const DILexicalBlockFile *N, SmallVectorImpl<uint64_t> &Record,
1839     unsigned Abbrev) {
1840   Record.push_back(N->isDistinct());
1841   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1842   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1843   Record.push_back(N->getDiscriminator());
1844 
1845   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK_FILE, Record, Abbrev);
1846   Record.clear();
1847 }
1848 
1849 void ModuleBitcodeWriter::writeDICommonBlock(const DICommonBlock *N,
1850                                              SmallVectorImpl<uint64_t> &Record,
1851                                              unsigned Abbrev) {
1852   Record.push_back(N->isDistinct());
1853   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1854   Record.push_back(VE.getMetadataOrNullID(N->getDecl()));
1855   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1856   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1857   Record.push_back(N->getLineNo());
1858 
1859   Stream.EmitRecord(bitc::METADATA_COMMON_BLOCK, Record, Abbrev);
1860   Record.clear();
1861 }
1862 
1863 void ModuleBitcodeWriter::writeDINamespace(const DINamespace *N,
1864                                            SmallVectorImpl<uint64_t> &Record,
1865                                            unsigned Abbrev) {
1866   Record.push_back(N->isDistinct() | N->getExportSymbols() << 1);
1867   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1868   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1869 
1870   Stream.EmitRecord(bitc::METADATA_NAMESPACE, Record, Abbrev);
1871   Record.clear();
1872 }
1873 
1874 void ModuleBitcodeWriter::writeDIMacro(const DIMacro *N,
1875                                        SmallVectorImpl<uint64_t> &Record,
1876                                        unsigned Abbrev) {
1877   Record.push_back(N->isDistinct());
1878   Record.push_back(N->getMacinfoType());
1879   Record.push_back(N->getLine());
1880   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1881   Record.push_back(VE.getMetadataOrNullID(N->getRawValue()));
1882 
1883   Stream.EmitRecord(bitc::METADATA_MACRO, Record, Abbrev);
1884   Record.clear();
1885 }
1886 
1887 void ModuleBitcodeWriter::writeDIMacroFile(const DIMacroFile *N,
1888                                            SmallVectorImpl<uint64_t> &Record,
1889                                            unsigned Abbrev) {
1890   Record.push_back(N->isDistinct());
1891   Record.push_back(N->getMacinfoType());
1892   Record.push_back(N->getLine());
1893   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1894   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1895 
1896   Stream.EmitRecord(bitc::METADATA_MACRO_FILE, Record, Abbrev);
1897   Record.clear();
1898 }
1899 
1900 void ModuleBitcodeWriter::writeDIArgList(const DIArgList *N,
1901                                          SmallVectorImpl<uint64_t> &Record,
1902                                          unsigned Abbrev) {
1903   Record.reserve(N->getArgs().size());
1904   for (ValueAsMetadata *MD : N->getArgs())
1905     Record.push_back(VE.getMetadataID(MD));
1906 
1907   Stream.EmitRecord(bitc::METADATA_ARG_LIST, Record, Abbrev);
1908   Record.clear();
1909 }
1910 
1911 void ModuleBitcodeWriter::writeDIModule(const DIModule *N,
1912                                         SmallVectorImpl<uint64_t> &Record,
1913                                         unsigned Abbrev) {
1914   Record.push_back(N->isDistinct());
1915   for (auto &I : N->operands())
1916     Record.push_back(VE.getMetadataOrNullID(I));
1917   Record.push_back(N->getLineNo());
1918   Record.push_back(N->getIsDecl());
1919 
1920   Stream.EmitRecord(bitc::METADATA_MODULE, Record, Abbrev);
1921   Record.clear();
1922 }
1923 
1924 void ModuleBitcodeWriter::writeDITemplateTypeParameter(
1925     const DITemplateTypeParameter *N, SmallVectorImpl<uint64_t> &Record,
1926     unsigned Abbrev) {
1927   Record.push_back(N->isDistinct());
1928   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1929   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1930   Record.push_back(N->isDefault());
1931 
1932   Stream.EmitRecord(bitc::METADATA_TEMPLATE_TYPE, Record, Abbrev);
1933   Record.clear();
1934 }
1935 
1936 void ModuleBitcodeWriter::writeDITemplateValueParameter(
1937     const DITemplateValueParameter *N, SmallVectorImpl<uint64_t> &Record,
1938     unsigned Abbrev) {
1939   Record.push_back(N->isDistinct());
1940   Record.push_back(N->getTag());
1941   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1942   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1943   Record.push_back(N->isDefault());
1944   Record.push_back(VE.getMetadataOrNullID(N->getValue()));
1945 
1946   Stream.EmitRecord(bitc::METADATA_TEMPLATE_VALUE, Record, Abbrev);
1947   Record.clear();
1948 }
1949 
1950 void ModuleBitcodeWriter::writeDIGlobalVariable(
1951     const DIGlobalVariable *N, SmallVectorImpl<uint64_t> &Record,
1952     unsigned Abbrev) {
1953   const uint64_t Version = 2 << 1;
1954   Record.push_back((uint64_t)N->isDistinct() | Version);
1955   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1956   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1957   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1958   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1959   Record.push_back(N->getLine());
1960   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1961   Record.push_back(N->isLocalToUnit());
1962   Record.push_back(N->isDefinition());
1963   Record.push_back(VE.getMetadataOrNullID(N->getStaticDataMemberDeclaration()));
1964   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams()));
1965   Record.push_back(N->getAlignInBits());
1966   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1967 
1968   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR, Record, Abbrev);
1969   Record.clear();
1970 }
1971 
1972 void ModuleBitcodeWriter::writeDILocalVariable(
1973     const DILocalVariable *N, SmallVectorImpl<uint64_t> &Record,
1974     unsigned Abbrev) {
1975   // In order to support all possible bitcode formats in BitcodeReader we need
1976   // to distinguish the following cases:
1977   // 1) Record has no artificial tag (Record[1]),
1978   //   has no obsolete inlinedAt field (Record[9]).
1979   //   In this case Record size will be 8, HasAlignment flag is false.
1980   // 2) Record has artificial tag (Record[1]),
1981   //   has no obsolete inlignedAt field (Record[9]).
1982   //   In this case Record size will be 9, HasAlignment flag is false.
1983   // 3) Record has both artificial tag (Record[1]) and
1984   //   obsolete inlignedAt field (Record[9]).
1985   //   In this case Record size will be 10, HasAlignment flag is false.
1986   // 4) Record has neither artificial tag, nor inlignedAt field, but
1987   //   HasAlignment flag is true and Record[8] contains alignment value.
1988   const uint64_t HasAlignmentFlag = 1 << 1;
1989   Record.push_back((uint64_t)N->isDistinct() | HasAlignmentFlag);
1990   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1991   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1992   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1993   Record.push_back(N->getLine());
1994   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1995   Record.push_back(N->getArg());
1996   Record.push_back(N->getFlags());
1997   Record.push_back(N->getAlignInBits());
1998   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1999 
2000   Stream.EmitRecord(bitc::METADATA_LOCAL_VAR, Record, Abbrev);
2001   Record.clear();
2002 }
2003 
2004 void ModuleBitcodeWriter::writeDILabel(
2005     const DILabel *N, SmallVectorImpl<uint64_t> &Record,
2006     unsigned Abbrev) {
2007   Record.push_back((uint64_t)N->isDistinct());
2008   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2009   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2010   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2011   Record.push_back(N->getLine());
2012 
2013   Stream.EmitRecord(bitc::METADATA_LABEL, Record, Abbrev);
2014   Record.clear();
2015 }
2016 
2017 void ModuleBitcodeWriter::writeDIExpression(const DIExpression *N,
2018                                             SmallVectorImpl<uint64_t> &Record,
2019                                             unsigned Abbrev) {
2020   Record.reserve(N->getElements().size() + 1);
2021   const uint64_t Version = 3 << 1;
2022   Record.push_back((uint64_t)N->isDistinct() | Version);
2023   Record.append(N->elements_begin(), N->elements_end());
2024 
2025   Stream.EmitRecord(bitc::METADATA_EXPRESSION, Record, Abbrev);
2026   Record.clear();
2027 }
2028 
2029 void ModuleBitcodeWriter::writeDIGlobalVariableExpression(
2030     const DIGlobalVariableExpression *N, SmallVectorImpl<uint64_t> &Record,
2031     unsigned Abbrev) {
2032   Record.push_back(N->isDistinct());
2033   Record.push_back(VE.getMetadataOrNullID(N->getVariable()));
2034   Record.push_back(VE.getMetadataOrNullID(N->getExpression()));
2035 
2036   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR_EXPR, Record, Abbrev);
2037   Record.clear();
2038 }
2039 
2040 void ModuleBitcodeWriter::writeDIObjCProperty(const DIObjCProperty *N,
2041                                               SmallVectorImpl<uint64_t> &Record,
2042                                               unsigned Abbrev) {
2043   Record.push_back(N->isDistinct());
2044   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2045   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2046   Record.push_back(N->getLine());
2047   Record.push_back(VE.getMetadataOrNullID(N->getRawSetterName()));
2048   Record.push_back(VE.getMetadataOrNullID(N->getRawGetterName()));
2049   Record.push_back(N->getAttributes());
2050   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2051 
2052   Stream.EmitRecord(bitc::METADATA_OBJC_PROPERTY, Record, Abbrev);
2053   Record.clear();
2054 }
2055 
2056 void ModuleBitcodeWriter::writeDIImportedEntity(
2057     const DIImportedEntity *N, SmallVectorImpl<uint64_t> &Record,
2058     unsigned Abbrev) {
2059   Record.push_back(N->isDistinct());
2060   Record.push_back(N->getTag());
2061   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2062   Record.push_back(VE.getMetadataOrNullID(N->getEntity()));
2063   Record.push_back(N->getLine());
2064   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2065   Record.push_back(VE.getMetadataOrNullID(N->getRawFile()));
2066   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
2067 
2068   Stream.EmitRecord(bitc::METADATA_IMPORTED_ENTITY, Record, Abbrev);
2069   Record.clear();
2070 }
2071 
2072 unsigned ModuleBitcodeWriter::createNamedMetadataAbbrev() {
2073   auto Abbv = std::make_shared<BitCodeAbbrev>();
2074   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
2075   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2076   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2077   return Stream.EmitAbbrev(std::move(Abbv));
2078 }
2079 
2080 void ModuleBitcodeWriter::writeNamedMetadata(
2081     SmallVectorImpl<uint64_t> &Record) {
2082   if (M.named_metadata_empty())
2083     return;
2084 
2085   unsigned Abbrev = createNamedMetadataAbbrev();
2086   for (const NamedMDNode &NMD : M.named_metadata()) {
2087     // Write name.
2088     StringRef Str = NMD.getName();
2089     Record.append(Str.bytes_begin(), Str.bytes_end());
2090     Stream.EmitRecord(bitc::METADATA_NAME, Record, Abbrev);
2091     Record.clear();
2092 
2093     // Write named metadata operands.
2094     for (const MDNode *N : NMD.operands())
2095       Record.push_back(VE.getMetadataID(N));
2096     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
2097     Record.clear();
2098   }
2099 }
2100 
2101 unsigned ModuleBitcodeWriter::createMetadataStringsAbbrev() {
2102   auto Abbv = std::make_shared<BitCodeAbbrev>();
2103   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRINGS));
2104   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // # of strings
2105   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // offset to chars
2106   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
2107   return Stream.EmitAbbrev(std::move(Abbv));
2108 }
2109 
2110 /// Write out a record for MDString.
2111 ///
2112 /// All the metadata strings in a metadata block are emitted in a single
2113 /// record.  The sizes and strings themselves are shoved into a blob.
2114 void ModuleBitcodeWriter::writeMetadataStrings(
2115     ArrayRef<const Metadata *> Strings, SmallVectorImpl<uint64_t> &Record) {
2116   if (Strings.empty())
2117     return;
2118 
2119   // Start the record with the number of strings.
2120   Record.push_back(bitc::METADATA_STRINGS);
2121   Record.push_back(Strings.size());
2122 
2123   // Emit the sizes of the strings in the blob.
2124   SmallString<256> Blob;
2125   {
2126     BitstreamWriter W(Blob);
2127     for (const Metadata *MD : Strings)
2128       W.EmitVBR(cast<MDString>(MD)->getLength(), 6);
2129     W.FlushToWord();
2130   }
2131 
2132   // Add the offset to the strings to the record.
2133   Record.push_back(Blob.size());
2134 
2135   // Add the strings to the blob.
2136   for (const Metadata *MD : Strings)
2137     Blob.append(cast<MDString>(MD)->getString());
2138 
2139   // Emit the final record.
2140   Stream.EmitRecordWithBlob(createMetadataStringsAbbrev(), Record, Blob);
2141   Record.clear();
2142 }
2143 
2144 // Generates an enum to use as an index in the Abbrev array of Metadata record.
2145 enum MetadataAbbrev : unsigned {
2146 #define HANDLE_MDNODE_LEAF(CLASS) CLASS##AbbrevID,
2147 #include "llvm/IR/Metadata.def"
2148   LastPlusOne
2149 };
2150 
2151 void ModuleBitcodeWriter::writeMetadataRecords(
2152     ArrayRef<const Metadata *> MDs, SmallVectorImpl<uint64_t> &Record,
2153     std::vector<unsigned> *MDAbbrevs, std::vector<uint64_t> *IndexPos) {
2154   if (MDs.empty())
2155     return;
2156 
2157   // Initialize MDNode abbreviations.
2158 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
2159 #include "llvm/IR/Metadata.def"
2160 
2161   for (const Metadata *MD : MDs) {
2162     if (IndexPos)
2163       IndexPos->push_back(Stream.GetCurrentBitNo());
2164     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
2165       assert(N->isResolved() && "Expected forward references to be resolved");
2166 
2167       switch (N->getMetadataID()) {
2168       default:
2169         llvm_unreachable("Invalid MDNode subclass");
2170 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
2171   case Metadata::CLASS##Kind:                                                  \
2172     if (MDAbbrevs)                                                             \
2173       write##CLASS(cast<CLASS>(N), Record,                                     \
2174                    (*MDAbbrevs)[MetadataAbbrev::CLASS##AbbrevID]);             \
2175     else                                                                       \
2176       write##CLASS(cast<CLASS>(N), Record, CLASS##Abbrev);                     \
2177     continue;
2178 #include "llvm/IR/Metadata.def"
2179       }
2180     }
2181     writeValueAsMetadata(cast<ValueAsMetadata>(MD), Record);
2182   }
2183 }
2184 
2185 void ModuleBitcodeWriter::writeModuleMetadata() {
2186   if (!VE.hasMDs() && M.named_metadata_empty())
2187     return;
2188 
2189   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 4);
2190   SmallVector<uint64_t, 64> Record;
2191 
2192   // Emit all abbrevs upfront, so that the reader can jump in the middle of the
2193   // block and load any metadata.
2194   std::vector<unsigned> MDAbbrevs;
2195 
2196   MDAbbrevs.resize(MetadataAbbrev::LastPlusOne);
2197   MDAbbrevs[MetadataAbbrev::DILocationAbbrevID] = createDILocationAbbrev();
2198   MDAbbrevs[MetadataAbbrev::GenericDINodeAbbrevID] =
2199       createGenericDINodeAbbrev();
2200 
2201   auto Abbv = std::make_shared<BitCodeAbbrev>();
2202   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX_OFFSET));
2203   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2204   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2205   unsigned OffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2206 
2207   Abbv = std::make_shared<BitCodeAbbrev>();
2208   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX));
2209   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2210   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2211   unsigned IndexAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2212 
2213   // Emit MDStrings together upfront.
2214   writeMetadataStrings(VE.getMDStrings(), Record);
2215 
2216   // We only emit an index for the metadata record if we have more than a given
2217   // (naive) threshold of metadatas, otherwise it is not worth it.
2218   if (VE.getNonMDStrings().size() > IndexThreshold) {
2219     // Write a placeholder value in for the offset of the metadata index,
2220     // which is written after the records, so that it can include
2221     // the offset of each entry. The placeholder offset will be
2222     // updated after all records are emitted.
2223     uint64_t Vals[] = {0, 0};
2224     Stream.EmitRecord(bitc::METADATA_INDEX_OFFSET, Vals, OffsetAbbrev);
2225   }
2226 
2227   // Compute and save the bit offset to the current position, which will be
2228   // patched when we emit the index later. We can simply subtract the 64-bit
2229   // fixed size from the current bit number to get the location to backpatch.
2230   uint64_t IndexOffsetRecordBitPos = Stream.GetCurrentBitNo();
2231 
2232   // This index will contain the bitpos for each individual record.
2233   std::vector<uint64_t> IndexPos;
2234   IndexPos.reserve(VE.getNonMDStrings().size());
2235 
2236   // Write all the records
2237   writeMetadataRecords(VE.getNonMDStrings(), Record, &MDAbbrevs, &IndexPos);
2238 
2239   if (VE.getNonMDStrings().size() > IndexThreshold) {
2240     // Now that we have emitted all the records we will emit the index. But
2241     // first
2242     // backpatch the forward reference so that the reader can skip the records
2243     // efficiently.
2244     Stream.BackpatchWord64(IndexOffsetRecordBitPos - 64,
2245                            Stream.GetCurrentBitNo() - IndexOffsetRecordBitPos);
2246 
2247     // Delta encode the index.
2248     uint64_t PreviousValue = IndexOffsetRecordBitPos;
2249     for (auto &Elt : IndexPos) {
2250       auto EltDelta = Elt - PreviousValue;
2251       PreviousValue = Elt;
2252       Elt = EltDelta;
2253     }
2254     // Emit the index record.
2255     Stream.EmitRecord(bitc::METADATA_INDEX, IndexPos, IndexAbbrev);
2256     IndexPos.clear();
2257   }
2258 
2259   // Write the named metadata now.
2260   writeNamedMetadata(Record);
2261 
2262   auto AddDeclAttachedMetadata = [&](const GlobalObject &GO) {
2263     SmallVector<uint64_t, 4> Record;
2264     Record.push_back(VE.getValueID(&GO));
2265     pushGlobalMetadataAttachment(Record, GO);
2266     Stream.EmitRecord(bitc::METADATA_GLOBAL_DECL_ATTACHMENT, Record);
2267   };
2268   for (const Function &F : M)
2269     if (F.isDeclaration() && F.hasMetadata())
2270       AddDeclAttachedMetadata(F);
2271   // FIXME: Only store metadata for declarations here, and move data for global
2272   // variable definitions to a separate block (PR28134).
2273   for (const GlobalVariable &GV : M.globals())
2274     if (GV.hasMetadata())
2275       AddDeclAttachedMetadata(GV);
2276 
2277   Stream.ExitBlock();
2278 }
2279 
2280 void ModuleBitcodeWriter::writeFunctionMetadata(const Function &F) {
2281   if (!VE.hasMDs())
2282     return;
2283 
2284   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
2285   SmallVector<uint64_t, 64> Record;
2286   writeMetadataStrings(VE.getMDStrings(), Record);
2287   writeMetadataRecords(VE.getNonMDStrings(), Record);
2288   Stream.ExitBlock();
2289 }
2290 
2291 void ModuleBitcodeWriter::pushGlobalMetadataAttachment(
2292     SmallVectorImpl<uint64_t> &Record, const GlobalObject &GO) {
2293   // [n x [id, mdnode]]
2294   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2295   GO.getAllMetadata(MDs);
2296   for (const auto &I : MDs) {
2297     Record.push_back(I.first);
2298     Record.push_back(VE.getMetadataID(I.second));
2299   }
2300 }
2301 
2302 void ModuleBitcodeWriter::writeFunctionMetadataAttachment(const Function &F) {
2303   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
2304 
2305   SmallVector<uint64_t, 64> Record;
2306 
2307   if (F.hasMetadata()) {
2308     pushGlobalMetadataAttachment(Record, F);
2309     Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2310     Record.clear();
2311   }
2312 
2313   // Write metadata attachments
2314   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
2315   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2316   for (const BasicBlock &BB : F)
2317     for (const Instruction &I : BB) {
2318       MDs.clear();
2319       I.getAllMetadataOtherThanDebugLoc(MDs);
2320 
2321       // If no metadata, ignore instruction.
2322       if (MDs.empty()) continue;
2323 
2324       Record.push_back(VE.getInstructionID(&I));
2325 
2326       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
2327         Record.push_back(MDs[i].first);
2328         Record.push_back(VE.getMetadataID(MDs[i].second));
2329       }
2330       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2331       Record.clear();
2332     }
2333 
2334   Stream.ExitBlock();
2335 }
2336 
2337 void ModuleBitcodeWriter::writeModuleMetadataKinds() {
2338   SmallVector<uint64_t, 64> Record;
2339 
2340   // Write metadata kinds
2341   // METADATA_KIND - [n x [id, name]]
2342   SmallVector<StringRef, 8> Names;
2343   M.getMDKindNames(Names);
2344 
2345   if (Names.empty()) return;
2346 
2347   Stream.EnterSubblock(bitc::METADATA_KIND_BLOCK_ID, 3);
2348 
2349   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
2350     Record.push_back(MDKindID);
2351     StringRef KName = Names[MDKindID];
2352     Record.append(KName.begin(), KName.end());
2353 
2354     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
2355     Record.clear();
2356   }
2357 
2358   Stream.ExitBlock();
2359 }
2360 
2361 void ModuleBitcodeWriter::writeOperandBundleTags() {
2362   // Write metadata kinds
2363   //
2364   // OPERAND_BUNDLE_TAGS_BLOCK_ID : N x OPERAND_BUNDLE_TAG
2365   //
2366   // OPERAND_BUNDLE_TAG - [strchr x N]
2367 
2368   SmallVector<StringRef, 8> Tags;
2369   M.getOperandBundleTags(Tags);
2370 
2371   if (Tags.empty())
2372     return;
2373 
2374   Stream.EnterSubblock(bitc::OPERAND_BUNDLE_TAGS_BLOCK_ID, 3);
2375 
2376   SmallVector<uint64_t, 64> Record;
2377 
2378   for (auto Tag : Tags) {
2379     Record.append(Tag.begin(), Tag.end());
2380 
2381     Stream.EmitRecord(bitc::OPERAND_BUNDLE_TAG, Record, 0);
2382     Record.clear();
2383   }
2384 
2385   Stream.ExitBlock();
2386 }
2387 
2388 void ModuleBitcodeWriter::writeSyncScopeNames() {
2389   SmallVector<StringRef, 8> SSNs;
2390   M.getContext().getSyncScopeNames(SSNs);
2391   if (SSNs.empty())
2392     return;
2393 
2394   Stream.EnterSubblock(bitc::SYNC_SCOPE_NAMES_BLOCK_ID, 2);
2395 
2396   SmallVector<uint64_t, 64> Record;
2397   for (auto SSN : SSNs) {
2398     Record.append(SSN.begin(), SSN.end());
2399     Stream.EmitRecord(bitc::SYNC_SCOPE_NAME, Record, 0);
2400     Record.clear();
2401   }
2402 
2403   Stream.ExitBlock();
2404 }
2405 
2406 void ModuleBitcodeWriter::writeConstants(unsigned FirstVal, unsigned LastVal,
2407                                          bool isGlobal) {
2408   if (FirstVal == LastVal) return;
2409 
2410   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
2411 
2412   unsigned AggregateAbbrev = 0;
2413   unsigned String8Abbrev = 0;
2414   unsigned CString7Abbrev = 0;
2415   unsigned CString6Abbrev = 0;
2416   // If this is a constant pool for the module, emit module-specific abbrevs.
2417   if (isGlobal) {
2418     // Abbrev for CST_CODE_AGGREGATE.
2419     auto Abbv = std::make_shared<BitCodeAbbrev>();
2420     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
2421     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2422     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
2423     AggregateAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2424 
2425     // Abbrev for CST_CODE_STRING.
2426     Abbv = std::make_shared<BitCodeAbbrev>();
2427     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
2428     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2429     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2430     String8Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2431     // Abbrev for CST_CODE_CSTRING.
2432     Abbv = std::make_shared<BitCodeAbbrev>();
2433     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2434     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2435     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2436     CString7Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2437     // Abbrev for CST_CODE_CSTRING.
2438     Abbv = std::make_shared<BitCodeAbbrev>();
2439     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2440     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2441     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2442     CString6Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2443   }
2444 
2445   SmallVector<uint64_t, 64> Record;
2446 
2447   const ValueEnumerator::ValueList &Vals = VE.getValues();
2448   Type *LastTy = nullptr;
2449   for (unsigned i = FirstVal; i != LastVal; ++i) {
2450     const Value *V = Vals[i].first;
2451     // If we need to switch types, do so now.
2452     if (V->getType() != LastTy) {
2453       LastTy = V->getType();
2454       Record.push_back(VE.getTypeID(LastTy));
2455       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
2456                         CONSTANTS_SETTYPE_ABBREV);
2457       Record.clear();
2458     }
2459 
2460     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
2461       Record.push_back(VE.getTypeID(IA->getFunctionType()));
2462       Record.push_back(
2463           unsigned(IA->hasSideEffects()) | unsigned(IA->isAlignStack()) << 1 |
2464           unsigned(IA->getDialect() & 1) << 2 | unsigned(IA->canThrow()) << 3);
2465 
2466       // Add the asm string.
2467       const std::string &AsmStr = IA->getAsmString();
2468       Record.push_back(AsmStr.size());
2469       Record.append(AsmStr.begin(), AsmStr.end());
2470 
2471       // Add the constraint string.
2472       const std::string &ConstraintStr = IA->getConstraintString();
2473       Record.push_back(ConstraintStr.size());
2474       Record.append(ConstraintStr.begin(), ConstraintStr.end());
2475       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
2476       Record.clear();
2477       continue;
2478     }
2479     const Constant *C = cast<Constant>(V);
2480     unsigned Code = -1U;
2481     unsigned AbbrevToUse = 0;
2482     if (C->isNullValue()) {
2483       Code = bitc::CST_CODE_NULL;
2484     } else if (isa<PoisonValue>(C)) {
2485       Code = bitc::CST_CODE_POISON;
2486     } else if (isa<UndefValue>(C)) {
2487       Code = bitc::CST_CODE_UNDEF;
2488     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
2489       if (IV->getBitWidth() <= 64) {
2490         uint64_t V = IV->getSExtValue();
2491         emitSignedInt64(Record, V);
2492         Code = bitc::CST_CODE_INTEGER;
2493         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
2494       } else {                             // Wide integers, > 64 bits in size.
2495         emitWideAPInt(Record, IV->getValue());
2496         Code = bitc::CST_CODE_WIDE_INTEGER;
2497       }
2498     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
2499       Code = bitc::CST_CODE_FLOAT;
2500       Type *Ty = CFP->getType();
2501       if (Ty->isHalfTy() || Ty->isBFloatTy() || Ty->isFloatTy() ||
2502           Ty->isDoubleTy()) {
2503         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
2504       } else if (Ty->isX86_FP80Ty()) {
2505         // api needed to prevent premature destruction
2506         // bits are not in the same order as a normal i80 APInt, compensate.
2507         APInt api = CFP->getValueAPF().bitcastToAPInt();
2508         const uint64_t *p = api.getRawData();
2509         Record.push_back((p[1] << 48) | (p[0] >> 16));
2510         Record.push_back(p[0] & 0xffffLL);
2511       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
2512         APInt api = CFP->getValueAPF().bitcastToAPInt();
2513         const uint64_t *p = api.getRawData();
2514         Record.push_back(p[0]);
2515         Record.push_back(p[1]);
2516       } else {
2517         assert(0 && "Unknown FP type!");
2518       }
2519     } else if (isa<ConstantDataSequential>(C) &&
2520                cast<ConstantDataSequential>(C)->isString()) {
2521       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
2522       // Emit constant strings specially.
2523       unsigned NumElts = Str->getNumElements();
2524       // If this is a null-terminated string, use the denser CSTRING encoding.
2525       if (Str->isCString()) {
2526         Code = bitc::CST_CODE_CSTRING;
2527         --NumElts;  // Don't encode the null, which isn't allowed by char6.
2528       } else {
2529         Code = bitc::CST_CODE_STRING;
2530         AbbrevToUse = String8Abbrev;
2531       }
2532       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
2533       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
2534       for (unsigned i = 0; i != NumElts; ++i) {
2535         unsigned char V = Str->getElementAsInteger(i);
2536         Record.push_back(V);
2537         isCStr7 &= (V & 128) == 0;
2538         if (isCStrChar6)
2539           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
2540       }
2541 
2542       if (isCStrChar6)
2543         AbbrevToUse = CString6Abbrev;
2544       else if (isCStr7)
2545         AbbrevToUse = CString7Abbrev;
2546     } else if (const ConstantDataSequential *CDS =
2547                   dyn_cast<ConstantDataSequential>(C)) {
2548       Code = bitc::CST_CODE_DATA;
2549       Type *EltTy = CDS->getElementType();
2550       if (isa<IntegerType>(EltTy)) {
2551         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2552           Record.push_back(CDS->getElementAsInteger(i));
2553       } else {
2554         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2555           Record.push_back(
2556               CDS->getElementAsAPFloat(i).bitcastToAPInt().getLimitedValue());
2557       }
2558     } else if (isa<ConstantAggregate>(C)) {
2559       Code = bitc::CST_CODE_AGGREGATE;
2560       for (const Value *Op : C->operands())
2561         Record.push_back(VE.getValueID(Op));
2562       AbbrevToUse = AggregateAbbrev;
2563     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
2564       switch (CE->getOpcode()) {
2565       default:
2566         if (Instruction::isCast(CE->getOpcode())) {
2567           Code = bitc::CST_CODE_CE_CAST;
2568           Record.push_back(getEncodedCastOpcode(CE->getOpcode()));
2569           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2570           Record.push_back(VE.getValueID(C->getOperand(0)));
2571           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
2572         } else {
2573           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
2574           Code = bitc::CST_CODE_CE_BINOP;
2575           Record.push_back(getEncodedBinaryOpcode(CE->getOpcode()));
2576           Record.push_back(VE.getValueID(C->getOperand(0)));
2577           Record.push_back(VE.getValueID(C->getOperand(1)));
2578           uint64_t Flags = getOptimizationFlags(CE);
2579           if (Flags != 0)
2580             Record.push_back(Flags);
2581         }
2582         break;
2583       case Instruction::FNeg: {
2584         assert(CE->getNumOperands() == 1 && "Unknown constant expr!");
2585         Code = bitc::CST_CODE_CE_UNOP;
2586         Record.push_back(getEncodedUnaryOpcode(CE->getOpcode()));
2587         Record.push_back(VE.getValueID(C->getOperand(0)));
2588         uint64_t Flags = getOptimizationFlags(CE);
2589         if (Flags != 0)
2590           Record.push_back(Flags);
2591         break;
2592       }
2593       case Instruction::GetElementPtr: {
2594         Code = bitc::CST_CODE_CE_GEP;
2595         const auto *GO = cast<GEPOperator>(C);
2596         Record.push_back(VE.getTypeID(GO->getSourceElementType()));
2597         if (Optional<unsigned> Idx = GO->getInRangeIndex()) {
2598           Code = bitc::CST_CODE_CE_GEP_WITH_INRANGE_INDEX;
2599           Record.push_back((*Idx << 1) | GO->isInBounds());
2600         } else if (GO->isInBounds())
2601           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
2602         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
2603           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
2604           Record.push_back(VE.getValueID(C->getOperand(i)));
2605         }
2606         break;
2607       }
2608       case Instruction::Select:
2609         Code = bitc::CST_CODE_CE_SELECT;
2610         Record.push_back(VE.getValueID(C->getOperand(0)));
2611         Record.push_back(VE.getValueID(C->getOperand(1)));
2612         Record.push_back(VE.getValueID(C->getOperand(2)));
2613         break;
2614       case Instruction::ExtractElement:
2615         Code = bitc::CST_CODE_CE_EXTRACTELT;
2616         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2617         Record.push_back(VE.getValueID(C->getOperand(0)));
2618         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
2619         Record.push_back(VE.getValueID(C->getOperand(1)));
2620         break;
2621       case Instruction::InsertElement:
2622         Code = bitc::CST_CODE_CE_INSERTELT;
2623         Record.push_back(VE.getValueID(C->getOperand(0)));
2624         Record.push_back(VE.getValueID(C->getOperand(1)));
2625         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
2626         Record.push_back(VE.getValueID(C->getOperand(2)));
2627         break;
2628       case Instruction::ShuffleVector:
2629         // If the return type and argument types are the same, this is a
2630         // standard shufflevector instruction.  If the types are different,
2631         // then the shuffle is widening or truncating the input vectors, and
2632         // the argument type must also be encoded.
2633         if (C->getType() == C->getOperand(0)->getType()) {
2634           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
2635         } else {
2636           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
2637           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2638         }
2639         Record.push_back(VE.getValueID(C->getOperand(0)));
2640         Record.push_back(VE.getValueID(C->getOperand(1)));
2641         Record.push_back(VE.getValueID(CE->getShuffleMaskForBitcode()));
2642         break;
2643       case Instruction::ICmp:
2644       case Instruction::FCmp:
2645         Code = bitc::CST_CODE_CE_CMP;
2646         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2647         Record.push_back(VE.getValueID(C->getOperand(0)));
2648         Record.push_back(VE.getValueID(C->getOperand(1)));
2649         Record.push_back(CE->getPredicate());
2650         break;
2651       }
2652     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
2653       Code = bitc::CST_CODE_BLOCKADDRESS;
2654       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
2655       Record.push_back(VE.getValueID(BA->getFunction()));
2656       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
2657     } else if (const auto *Equiv = dyn_cast<DSOLocalEquivalent>(C)) {
2658       Code = bitc::CST_CODE_DSO_LOCAL_EQUIVALENT;
2659       Record.push_back(VE.getTypeID(Equiv->getGlobalValue()->getType()));
2660       Record.push_back(VE.getValueID(Equiv->getGlobalValue()));
2661     } else if (const auto *NC = dyn_cast<NoCFIValue>(C)) {
2662       Code = bitc::CST_CODE_NO_CFI_VALUE;
2663       Record.push_back(VE.getTypeID(NC->getGlobalValue()->getType()));
2664       Record.push_back(VE.getValueID(NC->getGlobalValue()));
2665     } else {
2666 #ifndef NDEBUG
2667       C->dump();
2668 #endif
2669       llvm_unreachable("Unknown constant!");
2670     }
2671     Stream.EmitRecord(Code, Record, AbbrevToUse);
2672     Record.clear();
2673   }
2674 
2675   Stream.ExitBlock();
2676 }
2677 
2678 void ModuleBitcodeWriter::writeModuleConstants() {
2679   const ValueEnumerator::ValueList &Vals = VE.getValues();
2680 
2681   // Find the first constant to emit, which is the first non-globalvalue value.
2682   // We know globalvalues have been emitted by WriteModuleInfo.
2683   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
2684     if (!isa<GlobalValue>(Vals[i].first)) {
2685       writeConstants(i, Vals.size(), true);
2686       return;
2687     }
2688   }
2689 }
2690 
2691 /// pushValueAndType - The file has to encode both the value and type id for
2692 /// many values, because we need to know what type to create for forward
2693 /// references.  However, most operands are not forward references, so this type
2694 /// field is not needed.
2695 ///
2696 /// This function adds V's value ID to Vals.  If the value ID is higher than the
2697 /// instruction ID, then it is a forward reference, and it also includes the
2698 /// type ID.  The value ID that is written is encoded relative to the InstID.
2699 bool ModuleBitcodeWriter::pushValueAndType(const Value *V, unsigned InstID,
2700                                            SmallVectorImpl<unsigned> &Vals) {
2701   unsigned ValID = VE.getValueID(V);
2702   // Make encoding relative to the InstID.
2703   Vals.push_back(InstID - ValID);
2704   if (ValID >= InstID) {
2705     Vals.push_back(VE.getTypeID(V->getType()));
2706     return true;
2707   }
2708   return false;
2709 }
2710 
2711 void ModuleBitcodeWriter::writeOperandBundles(const CallBase &CS,
2712                                               unsigned InstID) {
2713   SmallVector<unsigned, 64> Record;
2714   LLVMContext &C = CS.getContext();
2715 
2716   for (unsigned i = 0, e = CS.getNumOperandBundles(); i != e; ++i) {
2717     const auto &Bundle = CS.getOperandBundleAt(i);
2718     Record.push_back(C.getOperandBundleTagID(Bundle.getTagName()));
2719 
2720     for (auto &Input : Bundle.Inputs)
2721       pushValueAndType(Input, InstID, Record);
2722 
2723     Stream.EmitRecord(bitc::FUNC_CODE_OPERAND_BUNDLE, Record);
2724     Record.clear();
2725   }
2726 }
2727 
2728 /// pushValue - Like pushValueAndType, but where the type of the value is
2729 /// omitted (perhaps it was already encoded in an earlier operand).
2730 void ModuleBitcodeWriter::pushValue(const Value *V, unsigned InstID,
2731                                     SmallVectorImpl<unsigned> &Vals) {
2732   unsigned ValID = VE.getValueID(V);
2733   Vals.push_back(InstID - ValID);
2734 }
2735 
2736 void ModuleBitcodeWriter::pushValueSigned(const Value *V, unsigned InstID,
2737                                           SmallVectorImpl<uint64_t> &Vals) {
2738   unsigned ValID = VE.getValueID(V);
2739   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
2740   emitSignedInt64(Vals, diff);
2741 }
2742 
2743 /// WriteInstruction - Emit an instruction to the specified stream.
2744 void ModuleBitcodeWriter::writeInstruction(const Instruction &I,
2745                                            unsigned InstID,
2746                                            SmallVectorImpl<unsigned> &Vals) {
2747   unsigned Code = 0;
2748   unsigned AbbrevToUse = 0;
2749   VE.setInstructionID(&I);
2750   switch (I.getOpcode()) {
2751   default:
2752     if (Instruction::isCast(I.getOpcode())) {
2753       Code = bitc::FUNC_CODE_INST_CAST;
2754       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2755         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
2756       Vals.push_back(VE.getTypeID(I.getType()));
2757       Vals.push_back(getEncodedCastOpcode(I.getOpcode()));
2758     } else {
2759       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
2760       Code = bitc::FUNC_CODE_INST_BINOP;
2761       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2762         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
2763       pushValue(I.getOperand(1), InstID, Vals);
2764       Vals.push_back(getEncodedBinaryOpcode(I.getOpcode()));
2765       uint64_t Flags = getOptimizationFlags(&I);
2766       if (Flags != 0) {
2767         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
2768           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
2769         Vals.push_back(Flags);
2770       }
2771     }
2772     break;
2773   case Instruction::FNeg: {
2774     Code = bitc::FUNC_CODE_INST_UNOP;
2775     if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2776       AbbrevToUse = FUNCTION_INST_UNOP_ABBREV;
2777     Vals.push_back(getEncodedUnaryOpcode(I.getOpcode()));
2778     uint64_t Flags = getOptimizationFlags(&I);
2779     if (Flags != 0) {
2780       if (AbbrevToUse == FUNCTION_INST_UNOP_ABBREV)
2781         AbbrevToUse = FUNCTION_INST_UNOP_FLAGS_ABBREV;
2782       Vals.push_back(Flags);
2783     }
2784     break;
2785   }
2786   case Instruction::GetElementPtr: {
2787     Code = bitc::FUNC_CODE_INST_GEP;
2788     AbbrevToUse = FUNCTION_INST_GEP_ABBREV;
2789     auto &GEPInst = cast<GetElementPtrInst>(I);
2790     Vals.push_back(GEPInst.isInBounds());
2791     Vals.push_back(VE.getTypeID(GEPInst.getSourceElementType()));
2792     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
2793       pushValueAndType(I.getOperand(i), InstID, Vals);
2794     break;
2795   }
2796   case Instruction::ExtractValue: {
2797     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
2798     pushValueAndType(I.getOperand(0), InstID, Vals);
2799     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
2800     Vals.append(EVI->idx_begin(), EVI->idx_end());
2801     break;
2802   }
2803   case Instruction::InsertValue: {
2804     Code = bitc::FUNC_CODE_INST_INSERTVAL;
2805     pushValueAndType(I.getOperand(0), InstID, Vals);
2806     pushValueAndType(I.getOperand(1), InstID, Vals);
2807     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
2808     Vals.append(IVI->idx_begin(), IVI->idx_end());
2809     break;
2810   }
2811   case Instruction::Select: {
2812     Code = bitc::FUNC_CODE_INST_VSELECT;
2813     pushValueAndType(I.getOperand(1), InstID, Vals);
2814     pushValue(I.getOperand(2), InstID, Vals);
2815     pushValueAndType(I.getOperand(0), InstID, Vals);
2816     uint64_t Flags = getOptimizationFlags(&I);
2817     if (Flags != 0)
2818       Vals.push_back(Flags);
2819     break;
2820   }
2821   case Instruction::ExtractElement:
2822     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
2823     pushValueAndType(I.getOperand(0), InstID, Vals);
2824     pushValueAndType(I.getOperand(1), InstID, Vals);
2825     break;
2826   case Instruction::InsertElement:
2827     Code = bitc::FUNC_CODE_INST_INSERTELT;
2828     pushValueAndType(I.getOperand(0), InstID, Vals);
2829     pushValue(I.getOperand(1), InstID, Vals);
2830     pushValueAndType(I.getOperand(2), InstID, Vals);
2831     break;
2832   case Instruction::ShuffleVector:
2833     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
2834     pushValueAndType(I.getOperand(0), InstID, Vals);
2835     pushValue(I.getOperand(1), InstID, Vals);
2836     pushValue(cast<ShuffleVectorInst>(I).getShuffleMaskForBitcode(), InstID,
2837               Vals);
2838     break;
2839   case Instruction::ICmp:
2840   case Instruction::FCmp: {
2841     // compare returning Int1Ty or vector of Int1Ty
2842     Code = bitc::FUNC_CODE_INST_CMP2;
2843     pushValueAndType(I.getOperand(0), InstID, Vals);
2844     pushValue(I.getOperand(1), InstID, Vals);
2845     Vals.push_back(cast<CmpInst>(I).getPredicate());
2846     uint64_t Flags = getOptimizationFlags(&I);
2847     if (Flags != 0)
2848       Vals.push_back(Flags);
2849     break;
2850   }
2851 
2852   case Instruction::Ret:
2853     {
2854       Code = bitc::FUNC_CODE_INST_RET;
2855       unsigned NumOperands = I.getNumOperands();
2856       if (NumOperands == 0)
2857         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
2858       else if (NumOperands == 1) {
2859         if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2860           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
2861       } else {
2862         for (unsigned i = 0, e = NumOperands; i != e; ++i)
2863           pushValueAndType(I.getOperand(i), InstID, Vals);
2864       }
2865     }
2866     break;
2867   case Instruction::Br:
2868     {
2869       Code = bitc::FUNC_CODE_INST_BR;
2870       const BranchInst &II = cast<BranchInst>(I);
2871       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
2872       if (II.isConditional()) {
2873         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
2874         pushValue(II.getCondition(), InstID, Vals);
2875       }
2876     }
2877     break;
2878   case Instruction::Switch:
2879     {
2880       Code = bitc::FUNC_CODE_INST_SWITCH;
2881       const SwitchInst &SI = cast<SwitchInst>(I);
2882       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
2883       pushValue(SI.getCondition(), InstID, Vals);
2884       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
2885       for (auto Case : SI.cases()) {
2886         Vals.push_back(VE.getValueID(Case.getCaseValue()));
2887         Vals.push_back(VE.getValueID(Case.getCaseSuccessor()));
2888       }
2889     }
2890     break;
2891   case Instruction::IndirectBr:
2892     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
2893     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2894     // Encode the address operand as relative, but not the basic blocks.
2895     pushValue(I.getOperand(0), InstID, Vals);
2896     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
2897       Vals.push_back(VE.getValueID(I.getOperand(i)));
2898     break;
2899 
2900   case Instruction::Invoke: {
2901     const InvokeInst *II = cast<InvokeInst>(&I);
2902     const Value *Callee = II->getCalledOperand();
2903     FunctionType *FTy = II->getFunctionType();
2904 
2905     if (II->hasOperandBundles())
2906       writeOperandBundles(*II, InstID);
2907 
2908     Code = bitc::FUNC_CODE_INST_INVOKE;
2909 
2910     Vals.push_back(VE.getAttributeListID(II->getAttributes()));
2911     Vals.push_back(II->getCallingConv() | 1 << 13);
2912     Vals.push_back(VE.getValueID(II->getNormalDest()));
2913     Vals.push_back(VE.getValueID(II->getUnwindDest()));
2914     Vals.push_back(VE.getTypeID(FTy));
2915     pushValueAndType(Callee, InstID, Vals);
2916 
2917     // Emit value #'s for the fixed parameters.
2918     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
2919       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
2920 
2921     // Emit type/value pairs for varargs params.
2922     if (FTy->isVarArg()) {
2923       for (unsigned i = FTy->getNumParams(), e = II->arg_size(); i != e; ++i)
2924         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
2925     }
2926     break;
2927   }
2928   case Instruction::Resume:
2929     Code = bitc::FUNC_CODE_INST_RESUME;
2930     pushValueAndType(I.getOperand(0), InstID, Vals);
2931     break;
2932   case Instruction::CleanupRet: {
2933     Code = bitc::FUNC_CODE_INST_CLEANUPRET;
2934     const auto &CRI = cast<CleanupReturnInst>(I);
2935     pushValue(CRI.getCleanupPad(), InstID, Vals);
2936     if (CRI.hasUnwindDest())
2937       Vals.push_back(VE.getValueID(CRI.getUnwindDest()));
2938     break;
2939   }
2940   case Instruction::CatchRet: {
2941     Code = bitc::FUNC_CODE_INST_CATCHRET;
2942     const auto &CRI = cast<CatchReturnInst>(I);
2943     pushValue(CRI.getCatchPad(), InstID, Vals);
2944     Vals.push_back(VE.getValueID(CRI.getSuccessor()));
2945     break;
2946   }
2947   case Instruction::CleanupPad:
2948   case Instruction::CatchPad: {
2949     const auto &FuncletPad = cast<FuncletPadInst>(I);
2950     Code = isa<CatchPadInst>(FuncletPad) ? bitc::FUNC_CODE_INST_CATCHPAD
2951                                          : bitc::FUNC_CODE_INST_CLEANUPPAD;
2952     pushValue(FuncletPad.getParentPad(), InstID, Vals);
2953 
2954     unsigned NumArgOperands = FuncletPad.getNumArgOperands();
2955     Vals.push_back(NumArgOperands);
2956     for (unsigned Op = 0; Op != NumArgOperands; ++Op)
2957       pushValueAndType(FuncletPad.getArgOperand(Op), InstID, Vals);
2958     break;
2959   }
2960   case Instruction::CatchSwitch: {
2961     Code = bitc::FUNC_CODE_INST_CATCHSWITCH;
2962     const auto &CatchSwitch = cast<CatchSwitchInst>(I);
2963 
2964     pushValue(CatchSwitch.getParentPad(), InstID, Vals);
2965 
2966     unsigned NumHandlers = CatchSwitch.getNumHandlers();
2967     Vals.push_back(NumHandlers);
2968     for (const BasicBlock *CatchPadBB : CatchSwitch.handlers())
2969       Vals.push_back(VE.getValueID(CatchPadBB));
2970 
2971     if (CatchSwitch.hasUnwindDest())
2972       Vals.push_back(VE.getValueID(CatchSwitch.getUnwindDest()));
2973     break;
2974   }
2975   case Instruction::CallBr: {
2976     const CallBrInst *CBI = cast<CallBrInst>(&I);
2977     const Value *Callee = CBI->getCalledOperand();
2978     FunctionType *FTy = CBI->getFunctionType();
2979 
2980     if (CBI->hasOperandBundles())
2981       writeOperandBundles(*CBI, InstID);
2982 
2983     Code = bitc::FUNC_CODE_INST_CALLBR;
2984 
2985     Vals.push_back(VE.getAttributeListID(CBI->getAttributes()));
2986 
2987     Vals.push_back(CBI->getCallingConv() << bitc::CALL_CCONV |
2988                    1 << bitc::CALL_EXPLICIT_TYPE);
2989 
2990     Vals.push_back(VE.getValueID(CBI->getDefaultDest()));
2991     Vals.push_back(CBI->getNumIndirectDests());
2992     for (unsigned i = 0, e = CBI->getNumIndirectDests(); i != e; ++i)
2993       Vals.push_back(VE.getValueID(CBI->getIndirectDest(i)));
2994 
2995     Vals.push_back(VE.getTypeID(FTy));
2996     pushValueAndType(Callee, InstID, Vals);
2997 
2998     // Emit value #'s for the fixed parameters.
2999     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
3000       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
3001 
3002     // Emit type/value pairs for varargs params.
3003     if (FTy->isVarArg()) {
3004       for (unsigned i = FTy->getNumParams(), e = CBI->arg_size(); i != e; ++i)
3005         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
3006     }
3007     break;
3008   }
3009   case Instruction::Unreachable:
3010     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
3011     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
3012     break;
3013 
3014   case Instruction::PHI: {
3015     const PHINode &PN = cast<PHINode>(I);
3016     Code = bitc::FUNC_CODE_INST_PHI;
3017     // With the newer instruction encoding, forward references could give
3018     // negative valued IDs.  This is most common for PHIs, so we use
3019     // signed VBRs.
3020     SmallVector<uint64_t, 128> Vals64;
3021     Vals64.push_back(VE.getTypeID(PN.getType()));
3022     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
3023       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64);
3024       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
3025     }
3026 
3027     uint64_t Flags = getOptimizationFlags(&I);
3028     if (Flags != 0)
3029       Vals64.push_back(Flags);
3030 
3031     // Emit a Vals64 vector and exit.
3032     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
3033     Vals64.clear();
3034     return;
3035   }
3036 
3037   case Instruction::LandingPad: {
3038     const LandingPadInst &LP = cast<LandingPadInst>(I);
3039     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
3040     Vals.push_back(VE.getTypeID(LP.getType()));
3041     Vals.push_back(LP.isCleanup());
3042     Vals.push_back(LP.getNumClauses());
3043     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
3044       if (LP.isCatch(I))
3045         Vals.push_back(LandingPadInst::Catch);
3046       else
3047         Vals.push_back(LandingPadInst::Filter);
3048       pushValueAndType(LP.getClause(I), InstID, Vals);
3049     }
3050     break;
3051   }
3052 
3053   case Instruction::Alloca: {
3054     Code = bitc::FUNC_CODE_INST_ALLOCA;
3055     const AllocaInst &AI = cast<AllocaInst>(I);
3056     Vals.push_back(VE.getTypeID(AI.getAllocatedType()));
3057     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
3058     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
3059     using APV = AllocaPackedValues;
3060     unsigned Record = 0;
3061     unsigned EncodedAlign = getEncodedAlign(AI.getAlign());
3062     Bitfield::set<APV::AlignLower>(
3063         Record, EncodedAlign & ((1 << APV::AlignLower::Bits) - 1));
3064     Bitfield::set<APV::AlignUpper>(Record,
3065                                    EncodedAlign >> APV::AlignLower::Bits);
3066     Bitfield::set<APV::UsedWithInAlloca>(Record, AI.isUsedWithInAlloca());
3067     Bitfield::set<APV::ExplicitType>(Record, true);
3068     Bitfield::set<APV::SwiftError>(Record, AI.isSwiftError());
3069     Vals.push_back(Record);
3070     break;
3071   }
3072 
3073   case Instruction::Load:
3074     if (cast<LoadInst>(I).isAtomic()) {
3075       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
3076       pushValueAndType(I.getOperand(0), InstID, Vals);
3077     } else {
3078       Code = bitc::FUNC_CODE_INST_LOAD;
3079       if (!pushValueAndType(I.getOperand(0), InstID, Vals)) // ptr
3080         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
3081     }
3082     Vals.push_back(VE.getTypeID(I.getType()));
3083     Vals.push_back(getEncodedAlign(cast<LoadInst>(I).getAlign()));
3084     Vals.push_back(cast<LoadInst>(I).isVolatile());
3085     if (cast<LoadInst>(I).isAtomic()) {
3086       Vals.push_back(getEncodedOrdering(cast<LoadInst>(I).getOrdering()));
3087       Vals.push_back(getEncodedSyncScopeID(cast<LoadInst>(I).getSyncScopeID()));
3088     }
3089     break;
3090   case Instruction::Store:
3091     if (cast<StoreInst>(I).isAtomic())
3092       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
3093     else
3094       Code = bitc::FUNC_CODE_INST_STORE;
3095     pushValueAndType(I.getOperand(1), InstID, Vals); // ptrty + ptr
3096     pushValueAndType(I.getOperand(0), InstID, Vals); // valty + val
3097     Vals.push_back(getEncodedAlign(cast<StoreInst>(I).getAlign()));
3098     Vals.push_back(cast<StoreInst>(I).isVolatile());
3099     if (cast<StoreInst>(I).isAtomic()) {
3100       Vals.push_back(getEncodedOrdering(cast<StoreInst>(I).getOrdering()));
3101       Vals.push_back(
3102           getEncodedSyncScopeID(cast<StoreInst>(I).getSyncScopeID()));
3103     }
3104     break;
3105   case Instruction::AtomicCmpXchg:
3106     Code = bitc::FUNC_CODE_INST_CMPXCHG;
3107     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
3108     pushValueAndType(I.getOperand(1), InstID, Vals); // cmp.
3109     pushValue(I.getOperand(2), InstID, Vals);        // newval.
3110     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
3111     Vals.push_back(
3112         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
3113     Vals.push_back(
3114         getEncodedSyncScopeID(cast<AtomicCmpXchgInst>(I).getSyncScopeID()));
3115     Vals.push_back(
3116         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
3117     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
3118     Vals.push_back(getEncodedAlign(cast<AtomicCmpXchgInst>(I).getAlign()));
3119     break;
3120   case Instruction::AtomicRMW:
3121     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
3122     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
3123     pushValueAndType(I.getOperand(1), InstID, Vals); // valty + val
3124     Vals.push_back(
3125         getEncodedRMWOperation(cast<AtomicRMWInst>(I).getOperation()));
3126     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
3127     Vals.push_back(getEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
3128     Vals.push_back(
3129         getEncodedSyncScopeID(cast<AtomicRMWInst>(I).getSyncScopeID()));
3130     Vals.push_back(getEncodedAlign(cast<AtomicRMWInst>(I).getAlign()));
3131     break;
3132   case Instruction::Fence:
3133     Code = bitc::FUNC_CODE_INST_FENCE;
3134     Vals.push_back(getEncodedOrdering(cast<FenceInst>(I).getOrdering()));
3135     Vals.push_back(getEncodedSyncScopeID(cast<FenceInst>(I).getSyncScopeID()));
3136     break;
3137   case Instruction::Call: {
3138     const CallInst &CI = cast<CallInst>(I);
3139     FunctionType *FTy = CI.getFunctionType();
3140 
3141     if (CI.hasOperandBundles())
3142       writeOperandBundles(CI, InstID);
3143 
3144     Code = bitc::FUNC_CODE_INST_CALL;
3145 
3146     Vals.push_back(VE.getAttributeListID(CI.getAttributes()));
3147 
3148     unsigned Flags = getOptimizationFlags(&I);
3149     Vals.push_back(CI.getCallingConv() << bitc::CALL_CCONV |
3150                    unsigned(CI.isTailCall()) << bitc::CALL_TAIL |
3151                    unsigned(CI.isMustTailCall()) << bitc::CALL_MUSTTAIL |
3152                    1 << bitc::CALL_EXPLICIT_TYPE |
3153                    unsigned(CI.isNoTailCall()) << bitc::CALL_NOTAIL |
3154                    unsigned(Flags != 0) << bitc::CALL_FMF);
3155     if (Flags != 0)
3156       Vals.push_back(Flags);
3157 
3158     Vals.push_back(VE.getTypeID(FTy));
3159     pushValueAndType(CI.getCalledOperand(), InstID, Vals); // Callee
3160 
3161     // Emit value #'s for the fixed parameters.
3162     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
3163       // Check for labels (can happen with asm labels).
3164       if (FTy->getParamType(i)->isLabelTy())
3165         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
3166       else
3167         pushValue(CI.getArgOperand(i), InstID, Vals); // fixed param.
3168     }
3169 
3170     // Emit type/value pairs for varargs params.
3171     if (FTy->isVarArg()) {
3172       for (unsigned i = FTy->getNumParams(), e = CI.arg_size(); i != e; ++i)
3173         pushValueAndType(CI.getArgOperand(i), InstID, Vals); // varargs
3174     }
3175     break;
3176   }
3177   case Instruction::VAArg:
3178     Code = bitc::FUNC_CODE_INST_VAARG;
3179     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
3180     pushValue(I.getOperand(0), InstID, Vals);                   // valist.
3181     Vals.push_back(VE.getTypeID(I.getType())); // restype.
3182     break;
3183   case Instruction::Freeze:
3184     Code = bitc::FUNC_CODE_INST_FREEZE;
3185     pushValueAndType(I.getOperand(0), InstID, Vals);
3186     break;
3187   }
3188 
3189   Stream.EmitRecord(Code, Vals, AbbrevToUse);
3190   Vals.clear();
3191 }
3192 
3193 /// Write a GlobalValue VST to the module. The purpose of this data structure is
3194 /// to allow clients to efficiently find the function body.
3195 void ModuleBitcodeWriter::writeGlobalValueSymbolTable(
3196   DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3197   // Get the offset of the VST we are writing, and backpatch it into
3198   // the VST forward declaration record.
3199   uint64_t VSTOffset = Stream.GetCurrentBitNo();
3200   // The BitcodeStartBit was the stream offset of the identification block.
3201   VSTOffset -= bitcodeStartBit();
3202   assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
3203   // Note that we add 1 here because the offset is relative to one word
3204   // before the start of the identification block, which was historically
3205   // always the start of the regular bitcode header.
3206   Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32 + 1);
3207 
3208   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3209 
3210   auto Abbv = std::make_shared<BitCodeAbbrev>();
3211   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
3212   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
3213   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
3214   unsigned FnEntryAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3215 
3216   for (const Function &F : M) {
3217     uint64_t Record[2];
3218 
3219     if (F.isDeclaration())
3220       continue;
3221 
3222     Record[0] = VE.getValueID(&F);
3223 
3224     // Save the word offset of the function (from the start of the
3225     // actual bitcode written to the stream).
3226     uint64_t BitcodeIndex = FunctionToBitcodeIndex[&F] - bitcodeStartBit();
3227     assert((BitcodeIndex & 31) == 0 && "function block not 32-bit aligned");
3228     // Note that we add 1 here because the offset is relative to one word
3229     // before the start of the identification block, which was historically
3230     // always the start of the regular bitcode header.
3231     Record[1] = BitcodeIndex / 32 + 1;
3232 
3233     Stream.EmitRecord(bitc::VST_CODE_FNENTRY, Record, FnEntryAbbrev);
3234   }
3235 
3236   Stream.ExitBlock();
3237 }
3238 
3239 /// Emit names for arguments, instructions and basic blocks in a function.
3240 void ModuleBitcodeWriter::writeFunctionLevelValueSymbolTable(
3241     const ValueSymbolTable &VST) {
3242   if (VST.empty())
3243     return;
3244 
3245   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3246 
3247   // FIXME: Set up the abbrev, we know how many values there are!
3248   // FIXME: We know if the type names can use 7-bit ascii.
3249   SmallVector<uint64_t, 64> NameVals;
3250 
3251   for (const ValueName &Name : VST) {
3252     // Figure out the encoding to use for the name.
3253     StringEncoding Bits = getStringEncoding(Name.getKey());
3254 
3255     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
3256     NameVals.push_back(VE.getValueID(Name.getValue()));
3257 
3258     // VST_CODE_ENTRY:   [valueid, namechar x N]
3259     // VST_CODE_BBENTRY: [bbid, namechar x N]
3260     unsigned Code;
3261     if (isa<BasicBlock>(Name.getValue())) {
3262       Code = bitc::VST_CODE_BBENTRY;
3263       if (Bits == SE_Char6)
3264         AbbrevToUse = VST_BBENTRY_6_ABBREV;
3265     } else {
3266       Code = bitc::VST_CODE_ENTRY;
3267       if (Bits == SE_Char6)
3268         AbbrevToUse = VST_ENTRY_6_ABBREV;
3269       else if (Bits == SE_Fixed7)
3270         AbbrevToUse = VST_ENTRY_7_ABBREV;
3271     }
3272 
3273     for (const auto P : Name.getKey())
3274       NameVals.push_back((unsigned char)P);
3275 
3276     // Emit the finished record.
3277     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
3278     NameVals.clear();
3279   }
3280 
3281   Stream.ExitBlock();
3282 }
3283 
3284 void ModuleBitcodeWriter::writeUseList(UseListOrder &&Order) {
3285   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
3286   unsigned Code;
3287   if (isa<BasicBlock>(Order.V))
3288     Code = bitc::USELIST_CODE_BB;
3289   else
3290     Code = bitc::USELIST_CODE_DEFAULT;
3291 
3292   SmallVector<uint64_t, 64> Record(Order.Shuffle.begin(), Order.Shuffle.end());
3293   Record.push_back(VE.getValueID(Order.V));
3294   Stream.EmitRecord(Code, Record);
3295 }
3296 
3297 void ModuleBitcodeWriter::writeUseListBlock(const Function *F) {
3298   assert(VE.shouldPreserveUseListOrder() &&
3299          "Expected to be preserving use-list order");
3300 
3301   auto hasMore = [&]() {
3302     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
3303   };
3304   if (!hasMore())
3305     // Nothing to do.
3306     return;
3307 
3308   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
3309   while (hasMore()) {
3310     writeUseList(std::move(VE.UseListOrders.back()));
3311     VE.UseListOrders.pop_back();
3312   }
3313   Stream.ExitBlock();
3314 }
3315 
3316 /// Emit a function body to the module stream.
3317 void ModuleBitcodeWriter::writeFunction(
3318     const Function &F,
3319     DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3320   // Save the bitcode index of the start of this function block for recording
3321   // in the VST.
3322   FunctionToBitcodeIndex[&F] = Stream.GetCurrentBitNo();
3323 
3324   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
3325   VE.incorporateFunction(F);
3326 
3327   SmallVector<unsigned, 64> Vals;
3328 
3329   // Emit the number of basic blocks, so the reader can create them ahead of
3330   // time.
3331   Vals.push_back(VE.getBasicBlocks().size());
3332   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
3333   Vals.clear();
3334 
3335   // If there are function-local constants, emit them now.
3336   unsigned CstStart, CstEnd;
3337   VE.getFunctionConstantRange(CstStart, CstEnd);
3338   writeConstants(CstStart, CstEnd, false);
3339 
3340   // If there is function-local metadata, emit it now.
3341   writeFunctionMetadata(F);
3342 
3343   // Keep a running idea of what the instruction ID is.
3344   unsigned InstID = CstEnd;
3345 
3346   bool NeedsMetadataAttachment = F.hasMetadata();
3347 
3348   DILocation *LastDL = nullptr;
3349   // Finally, emit all the instructions, in order.
3350   for (const BasicBlock &BB : F)
3351     for (const Instruction &I : BB) {
3352       writeInstruction(I, InstID, Vals);
3353 
3354       if (!I.getType()->isVoidTy())
3355         ++InstID;
3356 
3357       // If the instruction has metadata, write a metadata attachment later.
3358       NeedsMetadataAttachment |= I.hasMetadataOtherThanDebugLoc();
3359 
3360       // If the instruction has a debug location, emit it.
3361       DILocation *DL = I.getDebugLoc();
3362       if (!DL)
3363         continue;
3364 
3365       if (DL == LastDL) {
3366         // Just repeat the same debug loc as last time.
3367         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
3368         continue;
3369       }
3370 
3371       Vals.push_back(DL->getLine());
3372       Vals.push_back(DL->getColumn());
3373       Vals.push_back(VE.getMetadataOrNullID(DL->getScope()));
3374       Vals.push_back(VE.getMetadataOrNullID(DL->getInlinedAt()));
3375       Vals.push_back(DL->isImplicitCode());
3376       Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
3377       Vals.clear();
3378 
3379       LastDL = DL;
3380     }
3381 
3382   // Emit names for all the instructions etc.
3383   if (auto *Symtab = F.getValueSymbolTable())
3384     writeFunctionLevelValueSymbolTable(*Symtab);
3385 
3386   if (NeedsMetadataAttachment)
3387     writeFunctionMetadataAttachment(F);
3388   if (VE.shouldPreserveUseListOrder())
3389     writeUseListBlock(&F);
3390   VE.purgeFunction();
3391   Stream.ExitBlock();
3392 }
3393 
3394 // Emit blockinfo, which defines the standard abbreviations etc.
3395 void ModuleBitcodeWriter::writeBlockInfo() {
3396   // We only want to emit block info records for blocks that have multiple
3397   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
3398   // Other blocks can define their abbrevs inline.
3399   Stream.EnterBlockInfoBlock();
3400 
3401   { // 8-bit fixed-width VST_CODE_ENTRY/VST_CODE_BBENTRY strings.
3402     auto Abbv = std::make_shared<BitCodeAbbrev>();
3403     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
3404     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3405     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3406     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3407     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3408         VST_ENTRY_8_ABBREV)
3409       llvm_unreachable("Unexpected abbrev ordering!");
3410   }
3411 
3412   { // 7-bit fixed width VST_CODE_ENTRY strings.
3413     auto Abbv = std::make_shared<BitCodeAbbrev>();
3414     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3415     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3416     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3417     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3418     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3419         VST_ENTRY_7_ABBREV)
3420       llvm_unreachable("Unexpected abbrev ordering!");
3421   }
3422   { // 6-bit char6 VST_CODE_ENTRY strings.
3423     auto Abbv = std::make_shared<BitCodeAbbrev>();
3424     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3425     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3426     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3427     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3428     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3429         VST_ENTRY_6_ABBREV)
3430       llvm_unreachable("Unexpected abbrev ordering!");
3431   }
3432   { // 6-bit char6 VST_CODE_BBENTRY strings.
3433     auto Abbv = std::make_shared<BitCodeAbbrev>();
3434     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
3435     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3436     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3437     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3438     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3439         VST_BBENTRY_6_ABBREV)
3440       llvm_unreachable("Unexpected abbrev ordering!");
3441   }
3442 
3443   { // SETTYPE abbrev for CONSTANTS_BLOCK.
3444     auto Abbv = std::make_shared<BitCodeAbbrev>();
3445     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
3446     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
3447                               VE.computeBitsRequiredForTypeIndicies()));
3448     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3449         CONSTANTS_SETTYPE_ABBREV)
3450       llvm_unreachable("Unexpected abbrev ordering!");
3451   }
3452 
3453   { // INTEGER abbrev for CONSTANTS_BLOCK.
3454     auto Abbv = std::make_shared<BitCodeAbbrev>();
3455     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
3456     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3457     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3458         CONSTANTS_INTEGER_ABBREV)
3459       llvm_unreachable("Unexpected abbrev ordering!");
3460   }
3461 
3462   { // CE_CAST abbrev for CONSTANTS_BLOCK.
3463     auto Abbv = std::make_shared<BitCodeAbbrev>();
3464     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
3465     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
3466     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
3467                               VE.computeBitsRequiredForTypeIndicies()));
3468     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
3469 
3470     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3471         CONSTANTS_CE_CAST_Abbrev)
3472       llvm_unreachable("Unexpected abbrev ordering!");
3473   }
3474   { // NULL abbrev for CONSTANTS_BLOCK.
3475     auto Abbv = std::make_shared<BitCodeAbbrev>();
3476     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
3477     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3478         CONSTANTS_NULL_Abbrev)
3479       llvm_unreachable("Unexpected abbrev ordering!");
3480   }
3481 
3482   // FIXME: This should only use space for first class types!
3483 
3484   { // INST_LOAD abbrev for FUNCTION_BLOCK.
3485     auto Abbv = std::make_shared<BitCodeAbbrev>();
3486     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
3487     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
3488     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
3489                               VE.computeBitsRequiredForTypeIndicies()));
3490     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
3491     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
3492     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3493         FUNCTION_INST_LOAD_ABBREV)
3494       llvm_unreachable("Unexpected abbrev ordering!");
3495   }
3496   { // INST_UNOP abbrev for FUNCTION_BLOCK.
3497     auto Abbv = std::make_shared<BitCodeAbbrev>();
3498     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3499     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3500     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3501     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3502         FUNCTION_INST_UNOP_ABBREV)
3503       llvm_unreachable("Unexpected abbrev ordering!");
3504   }
3505   { // INST_UNOP_FLAGS abbrev for FUNCTION_BLOCK.
3506     auto Abbv = std::make_shared<BitCodeAbbrev>();
3507     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3508     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3509     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3510     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3511     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3512         FUNCTION_INST_UNOP_FLAGS_ABBREV)
3513       llvm_unreachable("Unexpected abbrev ordering!");
3514   }
3515   { // INST_BINOP abbrev for FUNCTION_BLOCK.
3516     auto Abbv = std::make_shared<BitCodeAbbrev>();
3517     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3518     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3519     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3520     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3521     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3522         FUNCTION_INST_BINOP_ABBREV)
3523       llvm_unreachable("Unexpected abbrev ordering!");
3524   }
3525   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
3526     auto Abbv = std::make_shared<BitCodeAbbrev>();
3527     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3528     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3529     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3530     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3531     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3532     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3533         FUNCTION_INST_BINOP_FLAGS_ABBREV)
3534       llvm_unreachable("Unexpected abbrev ordering!");
3535   }
3536   { // INST_CAST abbrev for FUNCTION_BLOCK.
3537     auto Abbv = std::make_shared<BitCodeAbbrev>();
3538     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
3539     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
3540     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
3541                               VE.computeBitsRequiredForTypeIndicies()));
3542     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
3543     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3544         FUNCTION_INST_CAST_ABBREV)
3545       llvm_unreachable("Unexpected abbrev ordering!");
3546   }
3547 
3548   { // INST_RET abbrev for FUNCTION_BLOCK.
3549     auto Abbv = std::make_shared<BitCodeAbbrev>();
3550     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3551     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3552         FUNCTION_INST_RET_VOID_ABBREV)
3553       llvm_unreachable("Unexpected abbrev ordering!");
3554   }
3555   { // INST_RET abbrev for FUNCTION_BLOCK.
3556     auto Abbv = std::make_shared<BitCodeAbbrev>();
3557     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3558     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
3559     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3560         FUNCTION_INST_RET_VAL_ABBREV)
3561       llvm_unreachable("Unexpected abbrev ordering!");
3562   }
3563   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
3564     auto Abbv = std::make_shared<BitCodeAbbrev>();
3565     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
3566     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3567         FUNCTION_INST_UNREACHABLE_ABBREV)
3568       llvm_unreachable("Unexpected abbrev ordering!");
3569   }
3570   {
3571     auto Abbv = std::make_shared<BitCodeAbbrev>();
3572     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_GEP));
3573     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
3574     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, // dest ty
3575                               Log2_32_Ceil(VE.getTypes().size() + 1)));
3576     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3577     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
3578     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3579         FUNCTION_INST_GEP_ABBREV)
3580       llvm_unreachable("Unexpected abbrev ordering!");
3581   }
3582 
3583   Stream.ExitBlock();
3584 }
3585 
3586 /// Write the module path strings, currently only used when generating
3587 /// a combined index file.
3588 void IndexBitcodeWriter::writeModStrings() {
3589   Stream.EnterSubblock(bitc::MODULE_STRTAB_BLOCK_ID, 3);
3590 
3591   // TODO: See which abbrev sizes we actually need to emit
3592 
3593   // 8-bit fixed-width MST_ENTRY strings.
3594   auto Abbv = std::make_shared<BitCodeAbbrev>();
3595   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3596   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3597   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3598   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3599   unsigned Abbrev8Bit = Stream.EmitAbbrev(std::move(Abbv));
3600 
3601   // 7-bit fixed width MST_ENTRY strings.
3602   Abbv = std::make_shared<BitCodeAbbrev>();
3603   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3604   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3605   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3606   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3607   unsigned Abbrev7Bit = Stream.EmitAbbrev(std::move(Abbv));
3608 
3609   // 6-bit char6 MST_ENTRY strings.
3610   Abbv = std::make_shared<BitCodeAbbrev>();
3611   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3612   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3613   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3614   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3615   unsigned Abbrev6Bit = Stream.EmitAbbrev(std::move(Abbv));
3616 
3617   // Module Hash, 160 bits SHA1. Optionally, emitted after each MST_CODE_ENTRY.
3618   Abbv = std::make_shared<BitCodeAbbrev>();
3619   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_HASH));
3620   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3621   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3622   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3623   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3624   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3625   unsigned AbbrevHash = Stream.EmitAbbrev(std::move(Abbv));
3626 
3627   SmallVector<unsigned, 64> Vals;
3628   forEachModule(
3629       [&](const StringMapEntry<std::pair<uint64_t, ModuleHash>> &MPSE) {
3630         StringRef Key = MPSE.getKey();
3631         const auto &Value = MPSE.getValue();
3632         StringEncoding Bits = getStringEncoding(Key);
3633         unsigned AbbrevToUse = Abbrev8Bit;
3634         if (Bits == SE_Char6)
3635           AbbrevToUse = Abbrev6Bit;
3636         else if (Bits == SE_Fixed7)
3637           AbbrevToUse = Abbrev7Bit;
3638 
3639         Vals.push_back(Value.first);
3640         Vals.append(Key.begin(), Key.end());
3641 
3642         // Emit the finished record.
3643         Stream.EmitRecord(bitc::MST_CODE_ENTRY, Vals, AbbrevToUse);
3644 
3645         // Emit an optional hash for the module now
3646         const auto &Hash = Value.second;
3647         if (llvm::any_of(Hash, [](uint32_t H) { return H; })) {
3648           Vals.assign(Hash.begin(), Hash.end());
3649           // Emit the hash record.
3650           Stream.EmitRecord(bitc::MST_CODE_HASH, Vals, AbbrevHash);
3651         }
3652 
3653         Vals.clear();
3654       });
3655   Stream.ExitBlock();
3656 }
3657 
3658 /// Write the function type metadata related records that need to appear before
3659 /// a function summary entry (whether per-module or combined).
3660 template <typename Fn>
3661 static void writeFunctionTypeMetadataRecords(BitstreamWriter &Stream,
3662                                              FunctionSummary *FS,
3663                                              Fn GetValueID) {
3664   if (!FS->type_tests().empty())
3665     Stream.EmitRecord(bitc::FS_TYPE_TESTS, FS->type_tests());
3666 
3667   SmallVector<uint64_t, 64> Record;
3668 
3669   auto WriteVFuncIdVec = [&](uint64_t Ty,
3670                              ArrayRef<FunctionSummary::VFuncId> VFs) {
3671     if (VFs.empty())
3672       return;
3673     Record.clear();
3674     for (auto &VF : VFs) {
3675       Record.push_back(VF.GUID);
3676       Record.push_back(VF.Offset);
3677     }
3678     Stream.EmitRecord(Ty, Record);
3679   };
3680 
3681   WriteVFuncIdVec(bitc::FS_TYPE_TEST_ASSUME_VCALLS,
3682                   FS->type_test_assume_vcalls());
3683   WriteVFuncIdVec(bitc::FS_TYPE_CHECKED_LOAD_VCALLS,
3684                   FS->type_checked_load_vcalls());
3685 
3686   auto WriteConstVCallVec = [&](uint64_t Ty,
3687                                 ArrayRef<FunctionSummary::ConstVCall> VCs) {
3688     for (auto &VC : VCs) {
3689       Record.clear();
3690       Record.push_back(VC.VFunc.GUID);
3691       Record.push_back(VC.VFunc.Offset);
3692       llvm::append_range(Record, VC.Args);
3693       Stream.EmitRecord(Ty, Record);
3694     }
3695   };
3696 
3697   WriteConstVCallVec(bitc::FS_TYPE_TEST_ASSUME_CONST_VCALL,
3698                      FS->type_test_assume_const_vcalls());
3699   WriteConstVCallVec(bitc::FS_TYPE_CHECKED_LOAD_CONST_VCALL,
3700                      FS->type_checked_load_const_vcalls());
3701 
3702   auto WriteRange = [&](ConstantRange Range) {
3703     Range = Range.sextOrTrunc(FunctionSummary::ParamAccess::RangeWidth);
3704     assert(Range.getLower().getNumWords() == 1);
3705     assert(Range.getUpper().getNumWords() == 1);
3706     emitSignedInt64(Record, *Range.getLower().getRawData());
3707     emitSignedInt64(Record, *Range.getUpper().getRawData());
3708   };
3709 
3710   if (!FS->paramAccesses().empty()) {
3711     Record.clear();
3712     for (auto &Arg : FS->paramAccesses()) {
3713       size_t UndoSize = Record.size();
3714       Record.push_back(Arg.ParamNo);
3715       WriteRange(Arg.Use);
3716       Record.push_back(Arg.Calls.size());
3717       for (auto &Call : Arg.Calls) {
3718         Record.push_back(Call.ParamNo);
3719         Optional<unsigned> ValueID = GetValueID(Call.Callee);
3720         if (!ValueID) {
3721           // If ValueID is unknown we can't drop just this call, we must drop
3722           // entire parameter.
3723           Record.resize(UndoSize);
3724           break;
3725         }
3726         Record.push_back(*ValueID);
3727         WriteRange(Call.Offsets);
3728       }
3729     }
3730     if (!Record.empty())
3731       Stream.EmitRecord(bitc::FS_PARAM_ACCESS, Record);
3732   }
3733 }
3734 
3735 /// Collect type IDs from type tests used by function.
3736 static void
3737 getReferencedTypeIds(FunctionSummary *FS,
3738                      std::set<GlobalValue::GUID> &ReferencedTypeIds) {
3739   if (!FS->type_tests().empty())
3740     for (auto &TT : FS->type_tests())
3741       ReferencedTypeIds.insert(TT);
3742 
3743   auto GetReferencedTypesFromVFuncIdVec =
3744       [&](ArrayRef<FunctionSummary::VFuncId> VFs) {
3745         for (auto &VF : VFs)
3746           ReferencedTypeIds.insert(VF.GUID);
3747       };
3748 
3749   GetReferencedTypesFromVFuncIdVec(FS->type_test_assume_vcalls());
3750   GetReferencedTypesFromVFuncIdVec(FS->type_checked_load_vcalls());
3751 
3752   auto GetReferencedTypesFromConstVCallVec =
3753       [&](ArrayRef<FunctionSummary::ConstVCall> VCs) {
3754         for (auto &VC : VCs)
3755           ReferencedTypeIds.insert(VC.VFunc.GUID);
3756       };
3757 
3758   GetReferencedTypesFromConstVCallVec(FS->type_test_assume_const_vcalls());
3759   GetReferencedTypesFromConstVCallVec(FS->type_checked_load_const_vcalls());
3760 }
3761 
3762 static void writeWholeProgramDevirtResolutionByArg(
3763     SmallVector<uint64_t, 64> &NameVals, const std::vector<uint64_t> &args,
3764     const WholeProgramDevirtResolution::ByArg &ByArg) {
3765   NameVals.push_back(args.size());
3766   llvm::append_range(NameVals, args);
3767 
3768   NameVals.push_back(ByArg.TheKind);
3769   NameVals.push_back(ByArg.Info);
3770   NameVals.push_back(ByArg.Byte);
3771   NameVals.push_back(ByArg.Bit);
3772 }
3773 
3774 static void writeWholeProgramDevirtResolution(
3775     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3776     uint64_t Id, const WholeProgramDevirtResolution &Wpd) {
3777   NameVals.push_back(Id);
3778 
3779   NameVals.push_back(Wpd.TheKind);
3780   NameVals.push_back(StrtabBuilder.add(Wpd.SingleImplName));
3781   NameVals.push_back(Wpd.SingleImplName.size());
3782 
3783   NameVals.push_back(Wpd.ResByArg.size());
3784   for (auto &A : Wpd.ResByArg)
3785     writeWholeProgramDevirtResolutionByArg(NameVals, A.first, A.second);
3786 }
3787 
3788 static void writeTypeIdSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
3789                                      StringTableBuilder &StrtabBuilder,
3790                                      const std::string &Id,
3791                                      const TypeIdSummary &Summary) {
3792   NameVals.push_back(StrtabBuilder.add(Id));
3793   NameVals.push_back(Id.size());
3794 
3795   NameVals.push_back(Summary.TTRes.TheKind);
3796   NameVals.push_back(Summary.TTRes.SizeM1BitWidth);
3797   NameVals.push_back(Summary.TTRes.AlignLog2);
3798   NameVals.push_back(Summary.TTRes.SizeM1);
3799   NameVals.push_back(Summary.TTRes.BitMask);
3800   NameVals.push_back(Summary.TTRes.InlineBits);
3801 
3802   for (auto &W : Summary.WPDRes)
3803     writeWholeProgramDevirtResolution(NameVals, StrtabBuilder, W.first,
3804                                       W.second);
3805 }
3806 
3807 static void writeTypeIdCompatibleVtableSummaryRecord(
3808     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3809     const std::string &Id, const TypeIdCompatibleVtableInfo &Summary,
3810     ValueEnumerator &VE) {
3811   NameVals.push_back(StrtabBuilder.add(Id));
3812   NameVals.push_back(Id.size());
3813 
3814   for (auto &P : Summary) {
3815     NameVals.push_back(P.AddressPointOffset);
3816     NameVals.push_back(VE.getValueID(P.VTableVI.getValue()));
3817   }
3818 }
3819 
3820 // Helper to emit a single function summary record.
3821 void ModuleBitcodeWriterBase::writePerModuleFunctionSummaryRecord(
3822     SmallVector<uint64_t, 64> &NameVals, GlobalValueSummary *Summary,
3823     unsigned ValueID, unsigned FSCallsAbbrev, unsigned FSCallsProfileAbbrev,
3824     const Function &F) {
3825   NameVals.push_back(ValueID);
3826 
3827   FunctionSummary *FS = cast<FunctionSummary>(Summary);
3828 
3829   writeFunctionTypeMetadataRecords(
3830       Stream, FS, [&](const ValueInfo &VI) -> Optional<unsigned> {
3831         return {VE.getValueID(VI.getValue())};
3832       });
3833 
3834   auto SpecialRefCnts = FS->specialRefCounts();
3835   NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
3836   NameVals.push_back(FS->instCount());
3837   NameVals.push_back(getEncodedFFlags(FS->fflags()));
3838   NameVals.push_back(FS->refs().size());
3839   NameVals.push_back(SpecialRefCnts.first);  // rorefcnt
3840   NameVals.push_back(SpecialRefCnts.second); // worefcnt
3841 
3842   for (auto &RI : FS->refs())
3843     NameVals.push_back(VE.getValueID(RI.getValue()));
3844 
3845   bool HasProfileData =
3846       F.hasProfileData() || ForceSummaryEdgesCold != FunctionSummary::FSHT_None;
3847   for (auto &ECI : FS->calls()) {
3848     NameVals.push_back(getValueId(ECI.first));
3849     if (HasProfileData)
3850       NameVals.push_back(static_cast<uint8_t>(ECI.second.Hotness));
3851     else if (WriteRelBFToSummary)
3852       NameVals.push_back(ECI.second.RelBlockFreq);
3853   }
3854 
3855   unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
3856   unsigned Code =
3857       (HasProfileData ? bitc::FS_PERMODULE_PROFILE
3858                       : (WriteRelBFToSummary ? bitc::FS_PERMODULE_RELBF
3859                                              : bitc::FS_PERMODULE));
3860 
3861   // Emit the finished record.
3862   Stream.EmitRecord(Code, NameVals, FSAbbrev);
3863   NameVals.clear();
3864 }
3865 
3866 // Collect the global value references in the given variable's initializer,
3867 // and emit them in a summary record.
3868 void ModuleBitcodeWriterBase::writeModuleLevelReferences(
3869     const GlobalVariable &V, SmallVector<uint64_t, 64> &NameVals,
3870     unsigned FSModRefsAbbrev, unsigned FSModVTableRefsAbbrev) {
3871   auto VI = Index->getValueInfo(V.getGUID());
3872   if (!VI || VI.getSummaryList().empty()) {
3873     // Only declarations should not have a summary (a declaration might however
3874     // have a summary if the def was in module level asm).
3875     assert(V.isDeclaration());
3876     return;
3877   }
3878   auto *Summary = VI.getSummaryList()[0].get();
3879   NameVals.push_back(VE.getValueID(&V));
3880   GlobalVarSummary *VS = cast<GlobalVarSummary>(Summary);
3881   NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
3882   NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
3883 
3884   auto VTableFuncs = VS->vTableFuncs();
3885   if (!VTableFuncs.empty())
3886     NameVals.push_back(VS->refs().size());
3887 
3888   unsigned SizeBeforeRefs = NameVals.size();
3889   for (auto &RI : VS->refs())
3890     NameVals.push_back(VE.getValueID(RI.getValue()));
3891   // Sort the refs for determinism output, the vector returned by FS->refs() has
3892   // been initialized from a DenseSet.
3893   llvm::sort(drop_begin(NameVals, SizeBeforeRefs));
3894 
3895   if (VTableFuncs.empty())
3896     Stream.EmitRecord(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS, NameVals,
3897                       FSModRefsAbbrev);
3898   else {
3899     // VTableFuncs pairs should already be sorted by offset.
3900     for (auto &P : VTableFuncs) {
3901       NameVals.push_back(VE.getValueID(P.FuncVI.getValue()));
3902       NameVals.push_back(P.VTableOffset);
3903     }
3904 
3905     Stream.EmitRecord(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS, NameVals,
3906                       FSModVTableRefsAbbrev);
3907   }
3908   NameVals.clear();
3909 }
3910 
3911 /// Emit the per-module summary section alongside the rest of
3912 /// the module's bitcode.
3913 void ModuleBitcodeWriterBase::writePerModuleGlobalValueSummary() {
3914   // By default we compile with ThinLTO if the module has a summary, but the
3915   // client can request full LTO with a module flag.
3916   bool IsThinLTO = true;
3917   if (auto *MD =
3918           mdconst::extract_or_null<ConstantInt>(M.getModuleFlag("ThinLTO")))
3919     IsThinLTO = MD->getZExtValue();
3920   Stream.EnterSubblock(IsThinLTO ? bitc::GLOBALVAL_SUMMARY_BLOCK_ID
3921                                  : bitc::FULL_LTO_GLOBALVAL_SUMMARY_BLOCK_ID,
3922                        4);
3923 
3924   Stream.EmitRecord(
3925       bitc::FS_VERSION,
3926       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
3927 
3928   // Write the index flags.
3929   uint64_t Flags = 0;
3930   // Bits 1-3 are set only in the combined index, skip them.
3931   if (Index->enableSplitLTOUnit())
3932     Flags |= 0x8;
3933   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Flags});
3934 
3935   if (Index->begin() == Index->end()) {
3936     Stream.ExitBlock();
3937     return;
3938   }
3939 
3940   for (const auto &GVI : valueIds()) {
3941     Stream.EmitRecord(bitc::FS_VALUE_GUID,
3942                       ArrayRef<uint64_t>{GVI.second, GVI.first});
3943   }
3944 
3945   // Abbrev for FS_PERMODULE_PROFILE.
3946   auto Abbv = std::make_shared<BitCodeAbbrev>();
3947   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_PROFILE));
3948   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3949   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3950   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3951   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3952   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3953   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
3954   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
3955   // numrefs x valueid, n x (valueid, hotness)
3956   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3957   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3958   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3959 
3960   // Abbrev for FS_PERMODULE or FS_PERMODULE_RELBF.
3961   Abbv = std::make_shared<BitCodeAbbrev>();
3962   if (WriteRelBFToSummary)
3963     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_RELBF));
3964   else
3965     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE));
3966   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3967   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3968   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3969   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3970   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3971   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
3972   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
3973   // numrefs x valueid, n x (valueid [, rel_block_freq])
3974   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3975   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3976   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3977 
3978   // Abbrev for FS_PERMODULE_GLOBALVAR_INIT_REFS.
3979   Abbv = std::make_shared<BitCodeAbbrev>();
3980   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS));
3981   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
3982   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
3983   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));  // valueids
3984   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3985   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3986 
3987   // Abbrev for FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS.
3988   Abbv = std::make_shared<BitCodeAbbrev>();
3989   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS));
3990   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
3991   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
3992   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numrefs
3993   // numrefs x valueid, n x (valueid , offset)
3994   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3995   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3996   unsigned FSModVTableRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3997 
3998   // Abbrev for FS_ALIAS.
3999   Abbv = std::make_shared<BitCodeAbbrev>();
4000   Abbv->Add(BitCodeAbbrevOp(bitc::FS_ALIAS));
4001   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4002   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4003   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4004   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4005 
4006   // Abbrev for FS_TYPE_ID_METADATA
4007   Abbv = std::make_shared<BitCodeAbbrev>();
4008   Abbv->Add(BitCodeAbbrevOp(bitc::FS_TYPE_ID_METADATA));
4009   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid strtab index
4010   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid length
4011   // n x (valueid , offset)
4012   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4013   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4014   unsigned TypeIdCompatibleVtableAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4015 
4016   SmallVector<uint64_t, 64> NameVals;
4017   // Iterate over the list of functions instead of the Index to
4018   // ensure the ordering is stable.
4019   for (const Function &F : M) {
4020     // Summary emission does not support anonymous functions, they have to
4021     // renamed using the anonymous function renaming pass.
4022     if (!F.hasName())
4023       report_fatal_error("Unexpected anonymous function when writing summary");
4024 
4025     ValueInfo VI = Index->getValueInfo(F.getGUID());
4026     if (!VI || VI.getSummaryList().empty()) {
4027       // Only declarations should not have a summary (a declaration might
4028       // however have a summary if the def was in module level asm).
4029       assert(F.isDeclaration());
4030       continue;
4031     }
4032     auto *Summary = VI.getSummaryList()[0].get();
4033     writePerModuleFunctionSummaryRecord(NameVals, Summary, VE.getValueID(&F),
4034                                         FSCallsAbbrev, FSCallsProfileAbbrev, F);
4035   }
4036 
4037   // Capture references from GlobalVariable initializers, which are outside
4038   // of a function scope.
4039   for (const GlobalVariable &G : M.globals())
4040     writeModuleLevelReferences(G, NameVals, FSModRefsAbbrev,
4041                                FSModVTableRefsAbbrev);
4042 
4043   for (const GlobalAlias &A : M.aliases()) {
4044     auto *Aliasee = A.getAliaseeObject();
4045     if (!Aliasee->hasName())
4046       // Nameless function don't have an entry in the summary, skip it.
4047       continue;
4048     auto AliasId = VE.getValueID(&A);
4049     auto AliaseeId = VE.getValueID(Aliasee);
4050     NameVals.push_back(AliasId);
4051     auto *Summary = Index->getGlobalValueSummary(A);
4052     AliasSummary *AS = cast<AliasSummary>(Summary);
4053     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
4054     NameVals.push_back(AliaseeId);
4055     Stream.EmitRecord(bitc::FS_ALIAS, NameVals, FSAliasAbbrev);
4056     NameVals.clear();
4057   }
4058 
4059   for (auto &S : Index->typeIdCompatibleVtableMap()) {
4060     writeTypeIdCompatibleVtableSummaryRecord(NameVals, StrtabBuilder, S.first,
4061                                              S.second, VE);
4062     Stream.EmitRecord(bitc::FS_TYPE_ID_METADATA, NameVals,
4063                       TypeIdCompatibleVtableAbbrev);
4064     NameVals.clear();
4065   }
4066 
4067   Stream.EmitRecord(bitc::FS_BLOCK_COUNT,
4068                     ArrayRef<uint64_t>{Index->getBlockCount()});
4069 
4070   Stream.ExitBlock();
4071 }
4072 
4073 /// Emit the combined summary section into the combined index file.
4074 void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
4075   Stream.EnterSubblock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID, 3);
4076   Stream.EmitRecord(
4077       bitc::FS_VERSION,
4078       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
4079 
4080   // Write the index flags.
4081   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Index.getFlags()});
4082 
4083   for (const auto &GVI : valueIds()) {
4084     Stream.EmitRecord(bitc::FS_VALUE_GUID,
4085                       ArrayRef<uint64_t>{GVI.second, GVI.first});
4086   }
4087 
4088   // Abbrev for FS_COMBINED.
4089   auto Abbv = std::make_shared<BitCodeAbbrev>();
4090   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED));
4091   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4092   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4093   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4094   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4095   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4096   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
4097   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4098   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4099   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4100   // numrefs x valueid, n x (valueid)
4101   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4102   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4103   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4104 
4105   // Abbrev for FS_COMBINED_PROFILE.
4106   Abbv = std::make_shared<BitCodeAbbrev>();
4107   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_PROFILE));
4108   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4109   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4110   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4111   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4112   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4113   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
4114   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4115   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4116   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4117   // numrefs x valueid, n x (valueid, hotness)
4118   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4119   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4120   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4121 
4122   // Abbrev for FS_COMBINED_GLOBALVAR_INIT_REFS.
4123   Abbv = std::make_shared<BitCodeAbbrev>();
4124   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS));
4125   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4126   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4127   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4128   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));    // valueids
4129   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4130   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4131 
4132   // Abbrev for FS_COMBINED_ALIAS.
4133   Abbv = std::make_shared<BitCodeAbbrev>();
4134   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_ALIAS));
4135   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4136   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4137   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4138   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4139   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4140 
4141   // The aliases are emitted as a post-pass, and will point to the value
4142   // id of the aliasee. Save them in a vector for post-processing.
4143   SmallVector<AliasSummary *, 64> Aliases;
4144 
4145   // Save the value id for each summary for alias emission.
4146   DenseMap<const GlobalValueSummary *, unsigned> SummaryToValueIdMap;
4147 
4148   SmallVector<uint64_t, 64> NameVals;
4149 
4150   // Set that will be populated during call to writeFunctionTypeMetadataRecords
4151   // with the type ids referenced by this index file.
4152   std::set<GlobalValue::GUID> ReferencedTypeIds;
4153 
4154   // For local linkage, we also emit the original name separately
4155   // immediately after the record.
4156   auto MaybeEmitOriginalName = [&](GlobalValueSummary &S) {
4157     // We don't need to emit the original name if we are writing the index for
4158     // distributed backends (in which case ModuleToSummariesForIndex is
4159     // non-null). The original name is only needed during the thin link, since
4160     // for SamplePGO the indirect call targets for local functions have
4161     // have the original name annotated in profile.
4162     // Continue to emit it when writing out the entire combined index, which is
4163     // used in testing the thin link via llvm-lto.
4164     if (ModuleToSummariesForIndex || !GlobalValue::isLocalLinkage(S.linkage()))
4165       return;
4166     NameVals.push_back(S.getOriginalName());
4167     Stream.EmitRecord(bitc::FS_COMBINED_ORIGINAL_NAME, NameVals);
4168     NameVals.clear();
4169   };
4170 
4171   std::set<GlobalValue::GUID> DefOrUseGUIDs;
4172   forEachSummary([&](GVInfo I, bool IsAliasee) {
4173     GlobalValueSummary *S = I.second;
4174     assert(S);
4175     DefOrUseGUIDs.insert(I.first);
4176     for (const ValueInfo &VI : S->refs())
4177       DefOrUseGUIDs.insert(VI.getGUID());
4178 
4179     auto ValueId = getValueId(I.first);
4180     assert(ValueId);
4181     SummaryToValueIdMap[S] = *ValueId;
4182 
4183     // If this is invoked for an aliasee, we want to record the above
4184     // mapping, but then not emit a summary entry (if the aliasee is
4185     // to be imported, we will invoke this separately with IsAliasee=false).
4186     if (IsAliasee)
4187       return;
4188 
4189     if (auto *AS = dyn_cast<AliasSummary>(S)) {
4190       // Will process aliases as a post-pass because the reader wants all
4191       // global to be loaded first.
4192       Aliases.push_back(AS);
4193       return;
4194     }
4195 
4196     if (auto *VS = dyn_cast<GlobalVarSummary>(S)) {
4197       NameVals.push_back(*ValueId);
4198       NameVals.push_back(Index.getModuleId(VS->modulePath()));
4199       NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
4200       NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
4201       for (auto &RI : VS->refs()) {
4202         auto RefValueId = getValueId(RI.getGUID());
4203         if (!RefValueId)
4204           continue;
4205         NameVals.push_back(*RefValueId);
4206       }
4207 
4208       // Emit the finished record.
4209       Stream.EmitRecord(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS, NameVals,
4210                         FSModRefsAbbrev);
4211       NameVals.clear();
4212       MaybeEmitOriginalName(*S);
4213       return;
4214     }
4215 
4216     auto GetValueId = [&](const ValueInfo &VI) -> Optional<unsigned> {
4217       return getValueId(VI.getGUID());
4218     };
4219 
4220     auto *FS = cast<FunctionSummary>(S);
4221     writeFunctionTypeMetadataRecords(Stream, FS, GetValueId);
4222     getReferencedTypeIds(FS, ReferencedTypeIds);
4223 
4224     NameVals.push_back(*ValueId);
4225     NameVals.push_back(Index.getModuleId(FS->modulePath()));
4226     NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
4227     NameVals.push_back(FS->instCount());
4228     NameVals.push_back(getEncodedFFlags(FS->fflags()));
4229     NameVals.push_back(FS->entryCount());
4230 
4231     // Fill in below
4232     NameVals.push_back(0); // numrefs
4233     NameVals.push_back(0); // rorefcnt
4234     NameVals.push_back(0); // worefcnt
4235 
4236     unsigned Count = 0, RORefCnt = 0, WORefCnt = 0;
4237     for (auto &RI : FS->refs()) {
4238       auto RefValueId = getValueId(RI.getGUID());
4239       if (!RefValueId)
4240         continue;
4241       NameVals.push_back(*RefValueId);
4242       if (RI.isReadOnly())
4243         RORefCnt++;
4244       else if (RI.isWriteOnly())
4245         WORefCnt++;
4246       Count++;
4247     }
4248     NameVals[6] = Count;
4249     NameVals[7] = RORefCnt;
4250     NameVals[8] = WORefCnt;
4251 
4252     bool HasProfileData = false;
4253     for (auto &EI : FS->calls()) {
4254       HasProfileData |=
4255           EI.second.getHotness() != CalleeInfo::HotnessType::Unknown;
4256       if (HasProfileData)
4257         break;
4258     }
4259 
4260     for (auto &EI : FS->calls()) {
4261       // If this GUID doesn't have a value id, it doesn't have a function
4262       // summary and we don't need to record any calls to it.
4263       Optional<unsigned> CallValueId = GetValueId(EI.first);
4264       if (!CallValueId)
4265         continue;
4266       NameVals.push_back(*CallValueId);
4267       if (HasProfileData)
4268         NameVals.push_back(static_cast<uint8_t>(EI.second.Hotness));
4269     }
4270 
4271     unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
4272     unsigned Code =
4273         (HasProfileData ? bitc::FS_COMBINED_PROFILE : bitc::FS_COMBINED);
4274 
4275     // Emit the finished record.
4276     Stream.EmitRecord(Code, NameVals, FSAbbrev);
4277     NameVals.clear();
4278     MaybeEmitOriginalName(*S);
4279   });
4280 
4281   for (auto *AS : Aliases) {
4282     auto AliasValueId = SummaryToValueIdMap[AS];
4283     assert(AliasValueId);
4284     NameVals.push_back(AliasValueId);
4285     NameVals.push_back(Index.getModuleId(AS->modulePath()));
4286     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
4287     auto AliaseeValueId = SummaryToValueIdMap[&AS->getAliasee()];
4288     assert(AliaseeValueId);
4289     NameVals.push_back(AliaseeValueId);
4290 
4291     // Emit the finished record.
4292     Stream.EmitRecord(bitc::FS_COMBINED_ALIAS, NameVals, FSAliasAbbrev);
4293     NameVals.clear();
4294     MaybeEmitOriginalName(*AS);
4295 
4296     if (auto *FS = dyn_cast<FunctionSummary>(&AS->getAliasee()))
4297       getReferencedTypeIds(FS, ReferencedTypeIds);
4298   }
4299 
4300   if (!Index.cfiFunctionDefs().empty()) {
4301     for (auto &S : Index.cfiFunctionDefs()) {
4302       if (DefOrUseGUIDs.count(
4303               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4304         NameVals.push_back(StrtabBuilder.add(S));
4305         NameVals.push_back(S.size());
4306       }
4307     }
4308     if (!NameVals.empty()) {
4309       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DEFS, NameVals);
4310       NameVals.clear();
4311     }
4312   }
4313 
4314   if (!Index.cfiFunctionDecls().empty()) {
4315     for (auto &S : Index.cfiFunctionDecls()) {
4316       if (DefOrUseGUIDs.count(
4317               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4318         NameVals.push_back(StrtabBuilder.add(S));
4319         NameVals.push_back(S.size());
4320       }
4321     }
4322     if (!NameVals.empty()) {
4323       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DECLS, NameVals);
4324       NameVals.clear();
4325     }
4326   }
4327 
4328   // Walk the GUIDs that were referenced, and write the
4329   // corresponding type id records.
4330   for (auto &T : ReferencedTypeIds) {
4331     auto TidIter = Index.typeIds().equal_range(T);
4332     for (auto It = TidIter.first; It != TidIter.second; ++It) {
4333       writeTypeIdSummaryRecord(NameVals, StrtabBuilder, It->second.first,
4334                                It->second.second);
4335       Stream.EmitRecord(bitc::FS_TYPE_ID, NameVals);
4336       NameVals.clear();
4337     }
4338   }
4339 
4340   Stream.EmitRecord(bitc::FS_BLOCK_COUNT,
4341                     ArrayRef<uint64_t>{Index.getBlockCount()});
4342 
4343   Stream.ExitBlock();
4344 }
4345 
4346 /// Create the "IDENTIFICATION_BLOCK_ID" containing a single string with the
4347 /// current llvm version, and a record for the epoch number.
4348 static void writeIdentificationBlock(BitstreamWriter &Stream) {
4349   Stream.EnterSubblock(bitc::IDENTIFICATION_BLOCK_ID, 5);
4350 
4351   // Write the "user readable" string identifying the bitcode producer
4352   auto Abbv = std::make_shared<BitCodeAbbrev>();
4353   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_STRING));
4354   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4355   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
4356   auto StringAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4357   writeStringRecord(Stream, bitc::IDENTIFICATION_CODE_STRING,
4358                     "LLVM" LLVM_VERSION_STRING, StringAbbrev);
4359 
4360   // Write the epoch version
4361   Abbv = std::make_shared<BitCodeAbbrev>();
4362   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_EPOCH));
4363   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
4364   auto EpochAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4365   constexpr std::array<unsigned, 1> Vals = {{bitc::BITCODE_CURRENT_EPOCH}};
4366   Stream.EmitRecord(bitc::IDENTIFICATION_CODE_EPOCH, Vals, EpochAbbrev);
4367   Stream.ExitBlock();
4368 }
4369 
4370 void ModuleBitcodeWriter::writeModuleHash(size_t BlockStartPos) {
4371   // Emit the module's hash.
4372   // MODULE_CODE_HASH: [5*i32]
4373   if (GenerateHash) {
4374     uint32_t Vals[5];
4375     Hasher.update(ArrayRef<uint8_t>((const uint8_t *)&(Buffer)[BlockStartPos],
4376                                     Buffer.size() - BlockStartPos));
4377     StringRef Hash = Hasher.result();
4378     for (int Pos = 0; Pos < 20; Pos += 4) {
4379       Vals[Pos / 4] = support::endian::read32be(Hash.data() + Pos);
4380     }
4381 
4382     // Emit the finished record.
4383     Stream.EmitRecord(bitc::MODULE_CODE_HASH, Vals);
4384 
4385     if (ModHash)
4386       // Save the written hash value.
4387       llvm::copy(Vals, std::begin(*ModHash));
4388   }
4389 }
4390 
4391 void ModuleBitcodeWriter::write() {
4392   writeIdentificationBlock(Stream);
4393 
4394   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4395   size_t BlockStartPos = Buffer.size();
4396 
4397   writeModuleVersion();
4398 
4399   // Emit blockinfo, which defines the standard abbreviations etc.
4400   writeBlockInfo();
4401 
4402   // Emit information describing all of the types in the module.
4403   writeTypeTable();
4404 
4405   // Emit information about attribute groups.
4406   writeAttributeGroupTable();
4407 
4408   // Emit information about parameter attributes.
4409   writeAttributeTable();
4410 
4411   writeComdats();
4412 
4413   // Emit top-level description of module, including target triple, inline asm,
4414   // descriptors for global variables, and function prototype info.
4415   writeModuleInfo();
4416 
4417   // Emit constants.
4418   writeModuleConstants();
4419 
4420   // Emit metadata kind names.
4421   writeModuleMetadataKinds();
4422 
4423   // Emit metadata.
4424   writeModuleMetadata();
4425 
4426   // Emit module-level use-lists.
4427   if (VE.shouldPreserveUseListOrder())
4428     writeUseListBlock(nullptr);
4429 
4430   writeOperandBundleTags();
4431   writeSyncScopeNames();
4432 
4433   // Emit function bodies.
4434   DenseMap<const Function *, uint64_t> FunctionToBitcodeIndex;
4435   for (const Function &F : M)
4436     if (!F.isDeclaration())
4437       writeFunction(F, FunctionToBitcodeIndex);
4438 
4439   // Need to write after the above call to WriteFunction which populates
4440   // the summary information in the index.
4441   if (Index)
4442     writePerModuleGlobalValueSummary();
4443 
4444   writeGlobalValueSymbolTable(FunctionToBitcodeIndex);
4445 
4446   writeModuleHash(BlockStartPos);
4447 
4448   Stream.ExitBlock();
4449 }
4450 
4451 static void writeInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
4452                                uint32_t &Position) {
4453   support::endian::write32le(&Buffer[Position], Value);
4454   Position += 4;
4455 }
4456 
4457 /// If generating a bc file on darwin, we have to emit a
4458 /// header and trailer to make it compatible with the system archiver.  To do
4459 /// this we emit the following header, and then emit a trailer that pads the
4460 /// file out to be a multiple of 16 bytes.
4461 ///
4462 /// struct bc_header {
4463 ///   uint32_t Magic;         // 0x0B17C0DE
4464 ///   uint32_t Version;       // Version, currently always 0.
4465 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
4466 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
4467 ///   uint32_t CPUType;       // CPU specifier.
4468 ///   ... potentially more later ...
4469 /// };
4470 static void emitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
4471                                          const Triple &TT) {
4472   unsigned CPUType = ~0U;
4473 
4474   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
4475   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
4476   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
4477   // specific constants here because they are implicitly part of the Darwin ABI.
4478   enum {
4479     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
4480     DARWIN_CPU_TYPE_X86        = 7,
4481     DARWIN_CPU_TYPE_ARM        = 12,
4482     DARWIN_CPU_TYPE_POWERPC    = 18
4483   };
4484 
4485   Triple::ArchType Arch = TT.getArch();
4486   if (Arch == Triple::x86_64)
4487     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
4488   else if (Arch == Triple::x86)
4489     CPUType = DARWIN_CPU_TYPE_X86;
4490   else if (Arch == Triple::ppc)
4491     CPUType = DARWIN_CPU_TYPE_POWERPC;
4492   else if (Arch == Triple::ppc64)
4493     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
4494   else if (Arch == Triple::arm || Arch == Triple::thumb)
4495     CPUType = DARWIN_CPU_TYPE_ARM;
4496 
4497   // Traditional Bitcode starts after header.
4498   assert(Buffer.size() >= BWH_HeaderSize &&
4499          "Expected header size to be reserved");
4500   unsigned BCOffset = BWH_HeaderSize;
4501   unsigned BCSize = Buffer.size() - BWH_HeaderSize;
4502 
4503   // Write the magic and version.
4504   unsigned Position = 0;
4505   writeInt32ToBuffer(0x0B17C0DE, Buffer, Position);
4506   writeInt32ToBuffer(0, Buffer, Position); // Version.
4507   writeInt32ToBuffer(BCOffset, Buffer, Position);
4508   writeInt32ToBuffer(BCSize, Buffer, Position);
4509   writeInt32ToBuffer(CPUType, Buffer, Position);
4510 
4511   // If the file is not a multiple of 16 bytes, insert dummy padding.
4512   while (Buffer.size() & 15)
4513     Buffer.push_back(0);
4514 }
4515 
4516 /// Helper to write the header common to all bitcode files.
4517 static void writeBitcodeHeader(BitstreamWriter &Stream) {
4518   // Emit the file header.
4519   Stream.Emit((unsigned)'B', 8);
4520   Stream.Emit((unsigned)'C', 8);
4521   Stream.Emit(0x0, 4);
4522   Stream.Emit(0xC, 4);
4523   Stream.Emit(0xE, 4);
4524   Stream.Emit(0xD, 4);
4525 }
4526 
4527 BitcodeWriter::BitcodeWriter(SmallVectorImpl<char> &Buffer, raw_fd_stream *FS)
4528     : Buffer(Buffer), Stream(new BitstreamWriter(Buffer, FS, FlushThreshold)) {
4529   writeBitcodeHeader(*Stream);
4530 }
4531 
4532 BitcodeWriter::~BitcodeWriter() { assert(WroteStrtab); }
4533 
4534 void BitcodeWriter::writeBlob(unsigned Block, unsigned Record, StringRef Blob) {
4535   Stream->EnterSubblock(Block, 3);
4536 
4537   auto Abbv = std::make_shared<BitCodeAbbrev>();
4538   Abbv->Add(BitCodeAbbrevOp(Record));
4539   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
4540   auto AbbrevNo = Stream->EmitAbbrev(std::move(Abbv));
4541 
4542   Stream->EmitRecordWithBlob(AbbrevNo, ArrayRef<uint64_t>{Record}, Blob);
4543 
4544   Stream->ExitBlock();
4545 }
4546 
4547 void BitcodeWriter::writeSymtab() {
4548   assert(!WroteStrtab && !WroteSymtab);
4549 
4550   // If any module has module-level inline asm, we will require a registered asm
4551   // parser for the target so that we can create an accurate symbol table for
4552   // the module.
4553   for (Module *M : Mods) {
4554     if (M->getModuleInlineAsm().empty())
4555       continue;
4556 
4557     std::string Err;
4558     const Triple TT(M->getTargetTriple());
4559     const Target *T = TargetRegistry::lookupTarget(TT.str(), Err);
4560     if (!T || !T->hasMCAsmParser())
4561       return;
4562   }
4563 
4564   WroteSymtab = true;
4565   SmallVector<char, 0> Symtab;
4566   // The irsymtab::build function may be unable to create a symbol table if the
4567   // module is malformed (e.g. it contains an invalid alias). Writing a symbol
4568   // table is not required for correctness, but we still want to be able to
4569   // write malformed modules to bitcode files, so swallow the error.
4570   if (Error E = irsymtab::build(Mods, Symtab, StrtabBuilder, Alloc)) {
4571     consumeError(std::move(E));
4572     return;
4573   }
4574 
4575   writeBlob(bitc::SYMTAB_BLOCK_ID, bitc::SYMTAB_BLOB,
4576             {Symtab.data(), Symtab.size()});
4577 }
4578 
4579 void BitcodeWriter::writeStrtab() {
4580   assert(!WroteStrtab);
4581 
4582   std::vector<char> Strtab;
4583   StrtabBuilder.finalizeInOrder();
4584   Strtab.resize(StrtabBuilder.getSize());
4585   StrtabBuilder.write((uint8_t *)Strtab.data());
4586 
4587   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB,
4588             {Strtab.data(), Strtab.size()});
4589 
4590   WroteStrtab = true;
4591 }
4592 
4593 void BitcodeWriter::copyStrtab(StringRef Strtab) {
4594   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB, Strtab);
4595   WroteStrtab = true;
4596 }
4597 
4598 void BitcodeWriter::writeModule(const Module &M,
4599                                 bool ShouldPreserveUseListOrder,
4600                                 const ModuleSummaryIndex *Index,
4601                                 bool GenerateHash, ModuleHash *ModHash) {
4602   assert(!WroteStrtab);
4603 
4604   // The Mods vector is used by irsymtab::build, which requires non-const
4605   // Modules in case it needs to materialize metadata. But the bitcode writer
4606   // requires that the module is materialized, so we can cast to non-const here,
4607   // after checking that it is in fact materialized.
4608   assert(M.isMaterialized());
4609   Mods.push_back(const_cast<Module *>(&M));
4610 
4611   ModuleBitcodeWriter ModuleWriter(M, Buffer, StrtabBuilder, *Stream,
4612                                    ShouldPreserveUseListOrder, Index,
4613                                    GenerateHash, ModHash);
4614   ModuleWriter.write();
4615 }
4616 
4617 void BitcodeWriter::writeIndex(
4618     const ModuleSummaryIndex *Index,
4619     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4620   IndexBitcodeWriter IndexWriter(*Stream, StrtabBuilder, *Index,
4621                                  ModuleToSummariesForIndex);
4622   IndexWriter.write();
4623 }
4624 
4625 /// Write the specified module to the specified output stream.
4626 void llvm::WriteBitcodeToFile(const Module &M, raw_ostream &Out,
4627                               bool ShouldPreserveUseListOrder,
4628                               const ModuleSummaryIndex *Index,
4629                               bool GenerateHash, ModuleHash *ModHash) {
4630   SmallVector<char, 0> Buffer;
4631   Buffer.reserve(256*1024);
4632 
4633   // If this is darwin or another generic macho target, reserve space for the
4634   // header.
4635   Triple TT(M.getTargetTriple());
4636   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4637     Buffer.insert(Buffer.begin(), BWH_HeaderSize, 0);
4638 
4639   BitcodeWriter Writer(Buffer, dyn_cast<raw_fd_stream>(&Out));
4640   Writer.writeModule(M, ShouldPreserveUseListOrder, Index, GenerateHash,
4641                      ModHash);
4642   Writer.writeSymtab();
4643   Writer.writeStrtab();
4644 
4645   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4646     emitDarwinBCHeaderAndTrailer(Buffer, TT);
4647 
4648   // Write the generated bitstream to "Out".
4649   if (!Buffer.empty())
4650     Out.write((char *)&Buffer.front(), Buffer.size());
4651 }
4652 
4653 void IndexBitcodeWriter::write() {
4654   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4655 
4656   writeModuleVersion();
4657 
4658   // Write the module paths in the combined index.
4659   writeModStrings();
4660 
4661   // Write the summary combined index records.
4662   writeCombinedGlobalValueSummary();
4663 
4664   Stream.ExitBlock();
4665 }
4666 
4667 // Write the specified module summary index to the given raw output stream,
4668 // where it will be written in a new bitcode block. This is used when
4669 // writing the combined index file for ThinLTO. When writing a subset of the
4670 // index for a distributed backend, provide a \p ModuleToSummariesForIndex map.
4671 void llvm::WriteIndexToFile(
4672     const ModuleSummaryIndex &Index, raw_ostream &Out,
4673     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4674   SmallVector<char, 0> Buffer;
4675   Buffer.reserve(256 * 1024);
4676 
4677   BitcodeWriter Writer(Buffer);
4678   Writer.writeIndex(&Index, ModuleToSummariesForIndex);
4679   Writer.writeStrtab();
4680 
4681   Out.write((char *)&Buffer.front(), Buffer.size());
4682 }
4683 
4684 namespace {
4685 
4686 /// Class to manage the bitcode writing for a thin link bitcode file.
4687 class ThinLinkBitcodeWriter : public ModuleBitcodeWriterBase {
4688   /// ModHash is for use in ThinLTO incremental build, generated while writing
4689   /// the module bitcode file.
4690   const ModuleHash *ModHash;
4691 
4692 public:
4693   ThinLinkBitcodeWriter(const Module &M, StringTableBuilder &StrtabBuilder,
4694                         BitstreamWriter &Stream,
4695                         const ModuleSummaryIndex &Index,
4696                         const ModuleHash &ModHash)
4697       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
4698                                 /*ShouldPreserveUseListOrder=*/false, &Index),
4699         ModHash(&ModHash) {}
4700 
4701   void write();
4702 
4703 private:
4704   void writeSimplifiedModuleInfo();
4705 };
4706 
4707 } // end anonymous namespace
4708 
4709 // This function writes a simpilified module info for thin link bitcode file.
4710 // It only contains the source file name along with the name(the offset and
4711 // size in strtab) and linkage for global values. For the global value info
4712 // entry, in order to keep linkage at offset 5, there are three zeros used
4713 // as padding.
4714 void ThinLinkBitcodeWriter::writeSimplifiedModuleInfo() {
4715   SmallVector<unsigned, 64> Vals;
4716   // Emit the module's source file name.
4717   {
4718     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
4719     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
4720     if (Bits == SE_Char6)
4721       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
4722     else if (Bits == SE_Fixed7)
4723       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
4724 
4725     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
4726     auto Abbv = std::make_shared<BitCodeAbbrev>();
4727     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
4728     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4729     Abbv->Add(AbbrevOpToUse);
4730     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4731 
4732     for (const auto P : M.getSourceFileName())
4733       Vals.push_back((unsigned char)P);
4734 
4735     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
4736     Vals.clear();
4737   }
4738 
4739   // Emit the global variable information.
4740   for (const GlobalVariable &GV : M.globals()) {
4741     // GLOBALVAR: [strtab offset, strtab size, 0, 0, 0, linkage]
4742     Vals.push_back(StrtabBuilder.add(GV.getName()));
4743     Vals.push_back(GV.getName().size());
4744     Vals.push_back(0);
4745     Vals.push_back(0);
4746     Vals.push_back(0);
4747     Vals.push_back(getEncodedLinkage(GV));
4748 
4749     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals);
4750     Vals.clear();
4751   }
4752 
4753   // Emit the function proto information.
4754   for (const Function &F : M) {
4755     // FUNCTION:  [strtab offset, strtab size, 0, 0, 0, linkage]
4756     Vals.push_back(StrtabBuilder.add(F.getName()));
4757     Vals.push_back(F.getName().size());
4758     Vals.push_back(0);
4759     Vals.push_back(0);
4760     Vals.push_back(0);
4761     Vals.push_back(getEncodedLinkage(F));
4762 
4763     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals);
4764     Vals.clear();
4765   }
4766 
4767   // Emit the alias information.
4768   for (const GlobalAlias &A : M.aliases()) {
4769     // ALIAS: [strtab offset, strtab size, 0, 0, 0, linkage]
4770     Vals.push_back(StrtabBuilder.add(A.getName()));
4771     Vals.push_back(A.getName().size());
4772     Vals.push_back(0);
4773     Vals.push_back(0);
4774     Vals.push_back(0);
4775     Vals.push_back(getEncodedLinkage(A));
4776 
4777     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals);
4778     Vals.clear();
4779   }
4780 
4781   // Emit the ifunc information.
4782   for (const GlobalIFunc &I : M.ifuncs()) {
4783     // IFUNC: [strtab offset, strtab size, 0, 0, 0, linkage]
4784     Vals.push_back(StrtabBuilder.add(I.getName()));
4785     Vals.push_back(I.getName().size());
4786     Vals.push_back(0);
4787     Vals.push_back(0);
4788     Vals.push_back(0);
4789     Vals.push_back(getEncodedLinkage(I));
4790 
4791     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
4792     Vals.clear();
4793   }
4794 }
4795 
4796 void ThinLinkBitcodeWriter::write() {
4797   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4798 
4799   writeModuleVersion();
4800 
4801   writeSimplifiedModuleInfo();
4802 
4803   writePerModuleGlobalValueSummary();
4804 
4805   // Write module hash.
4806   Stream.EmitRecord(bitc::MODULE_CODE_HASH, ArrayRef<uint32_t>(*ModHash));
4807 
4808   Stream.ExitBlock();
4809 }
4810 
4811 void BitcodeWriter::writeThinLinkBitcode(const Module &M,
4812                                          const ModuleSummaryIndex &Index,
4813                                          const ModuleHash &ModHash) {
4814   assert(!WroteStrtab);
4815 
4816   // The Mods vector is used by irsymtab::build, which requires non-const
4817   // Modules in case it needs to materialize metadata. But the bitcode writer
4818   // requires that the module is materialized, so we can cast to non-const here,
4819   // after checking that it is in fact materialized.
4820   assert(M.isMaterialized());
4821   Mods.push_back(const_cast<Module *>(&M));
4822 
4823   ThinLinkBitcodeWriter ThinLinkWriter(M, StrtabBuilder, *Stream, Index,
4824                                        ModHash);
4825   ThinLinkWriter.write();
4826 }
4827 
4828 // Write the specified thin link bitcode file to the given raw output stream,
4829 // where it will be written in a new bitcode block. This is used when
4830 // writing the per-module index file for ThinLTO.
4831 void llvm::WriteThinLinkBitcodeToFile(const Module &M, raw_ostream &Out,
4832                                       const ModuleSummaryIndex &Index,
4833                                       const ModuleHash &ModHash) {
4834   SmallVector<char, 0> Buffer;
4835   Buffer.reserve(256 * 1024);
4836 
4837   BitcodeWriter Writer(Buffer);
4838   Writer.writeThinLinkBitcode(M, Index, ModHash);
4839   Writer.writeSymtab();
4840   Writer.writeStrtab();
4841 
4842   Out.write((char *)&Buffer.front(), Buffer.size());
4843 }
4844 
4845 static const char *getSectionNameForBitcode(const Triple &T) {
4846   switch (T.getObjectFormat()) {
4847   case Triple::MachO:
4848     return "__LLVM,__bitcode";
4849   case Triple::COFF:
4850   case Triple::ELF:
4851   case Triple::Wasm:
4852   case Triple::UnknownObjectFormat:
4853     return ".llvmbc";
4854   case Triple::GOFF:
4855     llvm_unreachable("GOFF is not yet implemented");
4856     break;
4857   case Triple::XCOFF:
4858     llvm_unreachable("XCOFF is not yet implemented");
4859     break;
4860   }
4861   llvm_unreachable("Unimplemented ObjectFormatType");
4862 }
4863 
4864 static const char *getSectionNameForCommandline(const Triple &T) {
4865   switch (T.getObjectFormat()) {
4866   case Triple::MachO:
4867     return "__LLVM,__cmdline";
4868   case Triple::COFF:
4869   case Triple::ELF:
4870   case Triple::Wasm:
4871   case Triple::UnknownObjectFormat:
4872     return ".llvmcmd";
4873   case Triple::GOFF:
4874     llvm_unreachable("GOFF is not yet implemented");
4875     break;
4876   case Triple::XCOFF:
4877     llvm_unreachable("XCOFF is not yet implemented");
4878     break;
4879   }
4880   llvm_unreachable("Unimplemented ObjectFormatType");
4881 }
4882 
4883 void llvm::EmbedBitcodeInModule(llvm::Module &M, llvm::MemoryBufferRef Buf,
4884                                 bool EmbedBitcode, bool EmbedCmdline,
4885                                 const std::vector<uint8_t> &CmdArgs) {
4886   // Save llvm.compiler.used and remove it.
4887   SmallVector<Constant *, 2> UsedArray;
4888   SmallVector<GlobalValue *, 4> UsedGlobals;
4889   Type *UsedElementType = Type::getInt8Ty(M.getContext())->getPointerTo(0);
4890   GlobalVariable *Used = collectUsedGlobalVariables(M, UsedGlobals, true);
4891   for (auto *GV : UsedGlobals) {
4892     if (GV->getName() != "llvm.embedded.module" &&
4893         GV->getName() != "llvm.cmdline")
4894       UsedArray.push_back(
4895           ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
4896   }
4897   if (Used)
4898     Used->eraseFromParent();
4899 
4900   // Embed the bitcode for the llvm module.
4901   std::string Data;
4902   ArrayRef<uint8_t> ModuleData;
4903   Triple T(M.getTargetTriple());
4904 
4905   if (EmbedBitcode) {
4906     if (Buf.getBufferSize() == 0 ||
4907         !isBitcode((const unsigned char *)Buf.getBufferStart(),
4908                    (const unsigned char *)Buf.getBufferEnd())) {
4909       // If the input is LLVM Assembly, bitcode is produced by serializing
4910       // the module. Use-lists order need to be preserved in this case.
4911       llvm::raw_string_ostream OS(Data);
4912       llvm::WriteBitcodeToFile(M, OS, /* ShouldPreserveUseListOrder */ true);
4913       ModuleData =
4914           ArrayRef<uint8_t>((const uint8_t *)OS.str().data(), OS.str().size());
4915     } else
4916       // If the input is LLVM bitcode, write the input byte stream directly.
4917       ModuleData = ArrayRef<uint8_t>((const uint8_t *)Buf.getBufferStart(),
4918                                      Buf.getBufferSize());
4919   }
4920   llvm::Constant *ModuleConstant =
4921       llvm::ConstantDataArray::get(M.getContext(), ModuleData);
4922   llvm::GlobalVariable *GV = new llvm::GlobalVariable(
4923       M, ModuleConstant->getType(), true, llvm::GlobalValue::PrivateLinkage,
4924       ModuleConstant);
4925   GV->setSection(getSectionNameForBitcode(T));
4926   // Set alignment to 1 to prevent padding between two contributions from input
4927   // sections after linking.
4928   GV->setAlignment(Align(1));
4929   UsedArray.push_back(
4930       ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
4931   if (llvm::GlobalVariable *Old =
4932           M.getGlobalVariable("llvm.embedded.module", true)) {
4933     assert(Old->hasOneUse() &&
4934            "llvm.embedded.module can only be used once in llvm.compiler.used");
4935     GV->takeName(Old);
4936     Old->eraseFromParent();
4937   } else {
4938     GV->setName("llvm.embedded.module");
4939   }
4940 
4941   // Skip if only bitcode needs to be embedded.
4942   if (EmbedCmdline) {
4943     // Embed command-line options.
4944     ArrayRef<uint8_t> CmdData(const_cast<uint8_t *>(CmdArgs.data()),
4945                               CmdArgs.size());
4946     llvm::Constant *CmdConstant =
4947         llvm::ConstantDataArray::get(M.getContext(), CmdData);
4948     GV = new llvm::GlobalVariable(M, CmdConstant->getType(), true,
4949                                   llvm::GlobalValue::PrivateLinkage,
4950                                   CmdConstant);
4951     GV->setSection(getSectionNameForCommandline(T));
4952     GV->setAlignment(Align(1));
4953     UsedArray.push_back(
4954         ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
4955     if (llvm::GlobalVariable *Old = M.getGlobalVariable("llvm.cmdline", true)) {
4956       assert(Old->hasOneUse() &&
4957              "llvm.cmdline can only be used once in llvm.compiler.used");
4958       GV->takeName(Old);
4959       Old->eraseFromParent();
4960     } else {
4961       GV->setName("llvm.cmdline");
4962     }
4963   }
4964 
4965   if (UsedArray.empty())
4966     return;
4967 
4968   // Recreate llvm.compiler.used.
4969   ArrayType *ATy = ArrayType::get(UsedElementType, UsedArray.size());
4970   auto *NewUsed = new GlobalVariable(
4971       M, ATy, false, llvm::GlobalValue::AppendingLinkage,
4972       llvm::ConstantArray::get(ATy, UsedArray), "llvm.compiler.used");
4973   NewUsed->setSection("llvm.metadata");
4974 }
4975