xref: /llvm-project/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp (revision 430e22388173c96da6777fccb9735a6e8ee3ea1c)
1 //===- Bitcode/Writer/BitcodeWriter.cpp - Bitcode Writer ------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // Bitcode writer implementation.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "llvm/Bitcode/BitcodeWriter.h"
14 #include "ValueEnumerator.h"
15 #include "llvm/ADT/APFloat.h"
16 #include "llvm/ADT/APInt.h"
17 #include "llvm/ADT/ArrayRef.h"
18 #include "llvm/ADT/DenseMap.h"
19 #include "llvm/ADT/None.h"
20 #include "llvm/ADT/Optional.h"
21 #include "llvm/ADT/STLExtras.h"
22 #include "llvm/ADT/SmallString.h"
23 #include "llvm/ADT/SmallVector.h"
24 #include "llvm/ADT/StringMap.h"
25 #include "llvm/ADT/StringRef.h"
26 #include "llvm/ADT/Triple.h"
27 #include "llvm/Bitcode/BitcodeCommon.h"
28 #include "llvm/Bitcode/BitcodeReader.h"
29 #include "llvm/Bitcode/LLVMBitCodes.h"
30 #include "llvm/Bitstream/BitCodes.h"
31 #include "llvm/Bitstream/BitstreamWriter.h"
32 #include "llvm/Config/llvm-config.h"
33 #include "llvm/IR/Attributes.h"
34 #include "llvm/IR/BasicBlock.h"
35 #include "llvm/IR/Comdat.h"
36 #include "llvm/IR/Constant.h"
37 #include "llvm/IR/Constants.h"
38 #include "llvm/IR/DebugInfoMetadata.h"
39 #include "llvm/IR/DebugLoc.h"
40 #include "llvm/IR/DerivedTypes.h"
41 #include "llvm/IR/Function.h"
42 #include "llvm/IR/GlobalAlias.h"
43 #include "llvm/IR/GlobalIFunc.h"
44 #include "llvm/IR/GlobalObject.h"
45 #include "llvm/IR/GlobalValue.h"
46 #include "llvm/IR/GlobalVariable.h"
47 #include "llvm/IR/InlineAsm.h"
48 #include "llvm/IR/InstrTypes.h"
49 #include "llvm/IR/Instruction.h"
50 #include "llvm/IR/Instructions.h"
51 #include "llvm/IR/LLVMContext.h"
52 #include "llvm/IR/Metadata.h"
53 #include "llvm/IR/Module.h"
54 #include "llvm/IR/ModuleSummaryIndex.h"
55 #include "llvm/IR/Operator.h"
56 #include "llvm/IR/Type.h"
57 #include "llvm/IR/UseListOrder.h"
58 #include "llvm/IR/Value.h"
59 #include "llvm/IR/ValueSymbolTable.h"
60 #include "llvm/MC/StringTableBuilder.h"
61 #include "llvm/Object/IRSymtab.h"
62 #include "llvm/Support/AtomicOrdering.h"
63 #include "llvm/Support/Casting.h"
64 #include "llvm/Support/CommandLine.h"
65 #include "llvm/Support/Endian.h"
66 #include "llvm/Support/Error.h"
67 #include "llvm/Support/ErrorHandling.h"
68 #include "llvm/Support/MathExtras.h"
69 #include "llvm/Support/SHA1.h"
70 #include "llvm/Support/TargetRegistry.h"
71 #include "llvm/Support/raw_ostream.h"
72 #include <algorithm>
73 #include <cassert>
74 #include <cstddef>
75 #include <cstdint>
76 #include <iterator>
77 #include <map>
78 #include <memory>
79 #include <string>
80 #include <utility>
81 #include <vector>
82 
83 using namespace llvm;
84 
85 static cl::opt<unsigned>
86     IndexThreshold("bitcode-mdindex-threshold", cl::Hidden, cl::init(25),
87                    cl::desc("Number of metadatas above which we emit an index "
88                             "to enable lazy-loading"));
89 static cl::opt<uint32_t> FlushThreshold(
90     "bitcode-flush-threshold", cl::Hidden, cl::init(512),
91     cl::desc("The threshold (unit M) for flushing LLVM bitcode."));
92 
93 static cl::opt<bool> WriteRelBFToSummary(
94     "write-relbf-to-summary", cl::Hidden, cl::init(false),
95     cl::desc("Write relative block frequency to function summary "));
96 
97 extern FunctionSummary::ForceSummaryHotnessType ForceSummaryEdgesCold;
98 
99 namespace {
100 
101 /// These are manifest constants used by the bitcode writer. They do not need to
102 /// be kept in sync with the reader, but need to be consistent within this file.
103 enum {
104   // VALUE_SYMTAB_BLOCK abbrev id's.
105   VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
106   VST_ENTRY_7_ABBREV,
107   VST_ENTRY_6_ABBREV,
108   VST_BBENTRY_6_ABBREV,
109 
110   // CONSTANTS_BLOCK abbrev id's.
111   CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
112   CONSTANTS_INTEGER_ABBREV,
113   CONSTANTS_CE_CAST_Abbrev,
114   CONSTANTS_NULL_Abbrev,
115 
116   // FUNCTION_BLOCK abbrev id's.
117   FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
118   FUNCTION_INST_UNOP_ABBREV,
119   FUNCTION_INST_UNOP_FLAGS_ABBREV,
120   FUNCTION_INST_BINOP_ABBREV,
121   FUNCTION_INST_BINOP_FLAGS_ABBREV,
122   FUNCTION_INST_CAST_ABBREV,
123   FUNCTION_INST_RET_VOID_ABBREV,
124   FUNCTION_INST_RET_VAL_ABBREV,
125   FUNCTION_INST_UNREACHABLE_ABBREV,
126   FUNCTION_INST_GEP_ABBREV,
127 };
128 
129 /// Abstract class to manage the bitcode writing, subclassed for each bitcode
130 /// file type.
131 class BitcodeWriterBase {
132 protected:
133   /// The stream created and owned by the client.
134   BitstreamWriter &Stream;
135 
136   StringTableBuilder &StrtabBuilder;
137 
138 public:
139   /// Constructs a BitcodeWriterBase object that writes to the provided
140   /// \p Stream.
141   BitcodeWriterBase(BitstreamWriter &Stream, StringTableBuilder &StrtabBuilder)
142       : Stream(Stream), StrtabBuilder(StrtabBuilder) {}
143 
144 protected:
145   void writeModuleVersion();
146 };
147 
148 void BitcodeWriterBase::writeModuleVersion() {
149   // VERSION: [version#]
150   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, ArrayRef<uint64_t>{2});
151 }
152 
153 /// Base class to manage the module bitcode writing, currently subclassed for
154 /// ModuleBitcodeWriter and ThinLinkBitcodeWriter.
155 class ModuleBitcodeWriterBase : public BitcodeWriterBase {
156 protected:
157   /// The Module to write to bitcode.
158   const Module &M;
159 
160   /// Enumerates ids for all values in the module.
161   ValueEnumerator VE;
162 
163   /// Optional per-module index to write for ThinLTO.
164   const ModuleSummaryIndex *Index;
165 
166   /// Map that holds the correspondence between GUIDs in the summary index,
167   /// that came from indirect call profiles, and a value id generated by this
168   /// class to use in the VST and summary block records.
169   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
170 
171   /// Tracks the last value id recorded in the GUIDToValueMap.
172   unsigned GlobalValueId;
173 
174   /// Saves the offset of the VSTOffset record that must eventually be
175   /// backpatched with the offset of the actual VST.
176   uint64_t VSTOffsetPlaceholder = 0;
177 
178 public:
179   /// Constructs a ModuleBitcodeWriterBase object for the given Module,
180   /// writing to the provided \p Buffer.
181   ModuleBitcodeWriterBase(const Module &M, StringTableBuilder &StrtabBuilder,
182                           BitstreamWriter &Stream,
183                           bool ShouldPreserveUseListOrder,
184                           const ModuleSummaryIndex *Index)
185       : BitcodeWriterBase(Stream, StrtabBuilder), M(M),
186         VE(M, ShouldPreserveUseListOrder), Index(Index) {
187     // Assign ValueIds to any callee values in the index that came from
188     // indirect call profiles and were recorded as a GUID not a Value*
189     // (which would have been assigned an ID by the ValueEnumerator).
190     // The starting ValueId is just after the number of values in the
191     // ValueEnumerator, so that they can be emitted in the VST.
192     GlobalValueId = VE.getValues().size();
193     if (!Index)
194       return;
195     for (const auto &GUIDSummaryLists : *Index)
196       // Examine all summaries for this GUID.
197       for (auto &Summary : GUIDSummaryLists.second.SummaryList)
198         if (auto FS = dyn_cast<FunctionSummary>(Summary.get()))
199           // For each call in the function summary, see if the call
200           // is to a GUID (which means it is for an indirect call,
201           // otherwise we would have a Value for it). If so, synthesize
202           // a value id.
203           for (auto &CallEdge : FS->calls())
204             if (!CallEdge.first.haveGVs() || !CallEdge.first.getValue())
205               assignValueId(CallEdge.first.getGUID());
206   }
207 
208 protected:
209   void writePerModuleGlobalValueSummary();
210 
211 private:
212   void writePerModuleFunctionSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
213                                            GlobalValueSummary *Summary,
214                                            unsigned ValueID,
215                                            unsigned FSCallsAbbrev,
216                                            unsigned FSCallsProfileAbbrev,
217                                            const Function &F);
218   void writeModuleLevelReferences(const GlobalVariable &V,
219                                   SmallVector<uint64_t, 64> &NameVals,
220                                   unsigned FSModRefsAbbrev,
221                                   unsigned FSModVTableRefsAbbrev);
222 
223   void assignValueId(GlobalValue::GUID ValGUID) {
224     GUIDToValueIdMap[ValGUID] = ++GlobalValueId;
225   }
226 
227   unsigned getValueId(GlobalValue::GUID ValGUID) {
228     const auto &VMI = GUIDToValueIdMap.find(ValGUID);
229     // Expect that any GUID value had a value Id assigned by an
230     // earlier call to assignValueId.
231     assert(VMI != GUIDToValueIdMap.end() &&
232            "GUID does not have assigned value Id");
233     return VMI->second;
234   }
235 
236   // Helper to get the valueId for the type of value recorded in VI.
237   unsigned getValueId(ValueInfo VI) {
238     if (!VI.haveGVs() || !VI.getValue())
239       return getValueId(VI.getGUID());
240     return VE.getValueID(VI.getValue());
241   }
242 
243   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
244 };
245 
246 /// Class to manage the bitcode writing for a module.
247 class ModuleBitcodeWriter : public ModuleBitcodeWriterBase {
248   /// Pointer to the buffer allocated by caller for bitcode writing.
249   const SmallVectorImpl<char> &Buffer;
250 
251   /// True if a module hash record should be written.
252   bool GenerateHash;
253 
254   /// If non-null, when GenerateHash is true, the resulting hash is written
255   /// into ModHash.
256   ModuleHash *ModHash;
257 
258   SHA1 Hasher;
259 
260   /// The start bit of the identification block.
261   uint64_t BitcodeStartBit;
262 
263 public:
264   /// Constructs a ModuleBitcodeWriter object for the given Module,
265   /// writing to the provided \p Buffer.
266   ModuleBitcodeWriter(const Module &M, SmallVectorImpl<char> &Buffer,
267                       StringTableBuilder &StrtabBuilder,
268                       BitstreamWriter &Stream, bool ShouldPreserveUseListOrder,
269                       const ModuleSummaryIndex *Index, bool GenerateHash,
270                       ModuleHash *ModHash = nullptr)
271       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
272                                 ShouldPreserveUseListOrder, Index),
273         Buffer(Buffer), GenerateHash(GenerateHash), ModHash(ModHash),
274         BitcodeStartBit(Stream.GetCurrentBitNo()) {}
275 
276   /// Emit the current module to the bitstream.
277   void write();
278 
279 private:
280   uint64_t bitcodeStartBit() { return BitcodeStartBit; }
281 
282   size_t addToStrtab(StringRef Str);
283 
284   void writeAttributeGroupTable();
285   void writeAttributeTable();
286   void writeTypeTable();
287   void writeComdats();
288   void writeValueSymbolTableForwardDecl();
289   void writeModuleInfo();
290   void writeValueAsMetadata(const ValueAsMetadata *MD,
291                             SmallVectorImpl<uint64_t> &Record);
292   void writeMDTuple(const MDTuple *N, SmallVectorImpl<uint64_t> &Record,
293                     unsigned Abbrev);
294   unsigned createDILocationAbbrev();
295   void writeDILocation(const DILocation *N, SmallVectorImpl<uint64_t> &Record,
296                        unsigned &Abbrev);
297   unsigned createGenericDINodeAbbrev();
298   void writeGenericDINode(const GenericDINode *N,
299                           SmallVectorImpl<uint64_t> &Record, unsigned &Abbrev);
300   void writeDISubrange(const DISubrange *N, SmallVectorImpl<uint64_t> &Record,
301                        unsigned Abbrev);
302   void writeDIGenericSubrange(const DIGenericSubrange *N,
303                               SmallVectorImpl<uint64_t> &Record,
304                               unsigned Abbrev);
305   void writeDIEnumerator(const DIEnumerator *N,
306                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
307   void writeDIBasicType(const DIBasicType *N, SmallVectorImpl<uint64_t> &Record,
308                         unsigned Abbrev);
309   void writeDIStringType(const DIStringType *N,
310                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
311   void writeDIDerivedType(const DIDerivedType *N,
312                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
313   void writeDICompositeType(const DICompositeType *N,
314                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
315   void writeDISubroutineType(const DISubroutineType *N,
316                              SmallVectorImpl<uint64_t> &Record,
317                              unsigned Abbrev);
318   void writeDIFile(const DIFile *N, SmallVectorImpl<uint64_t> &Record,
319                    unsigned Abbrev);
320   void writeDICompileUnit(const DICompileUnit *N,
321                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
322   void writeDISubprogram(const DISubprogram *N,
323                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
324   void writeDILexicalBlock(const DILexicalBlock *N,
325                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
326   void writeDILexicalBlockFile(const DILexicalBlockFile *N,
327                                SmallVectorImpl<uint64_t> &Record,
328                                unsigned Abbrev);
329   void writeDICommonBlock(const DICommonBlock *N,
330                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
331   void writeDINamespace(const DINamespace *N, SmallVectorImpl<uint64_t> &Record,
332                         unsigned Abbrev);
333   void writeDIMacro(const DIMacro *N, SmallVectorImpl<uint64_t> &Record,
334                     unsigned Abbrev);
335   void writeDIMacroFile(const DIMacroFile *N, SmallVectorImpl<uint64_t> &Record,
336                         unsigned Abbrev);
337   void writeDIArgList(const DIArgList *N, SmallVectorImpl<uint64_t> &Record,
338                       unsigned Abbrev);
339   void writeDIModule(const DIModule *N, SmallVectorImpl<uint64_t> &Record,
340                      unsigned Abbrev);
341   void writeDITemplateTypeParameter(const DITemplateTypeParameter *N,
342                                     SmallVectorImpl<uint64_t> &Record,
343                                     unsigned Abbrev);
344   void writeDITemplateValueParameter(const DITemplateValueParameter *N,
345                                      SmallVectorImpl<uint64_t> &Record,
346                                      unsigned Abbrev);
347   void writeDIGlobalVariable(const DIGlobalVariable *N,
348                              SmallVectorImpl<uint64_t> &Record,
349                              unsigned Abbrev);
350   void writeDILocalVariable(const DILocalVariable *N,
351                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
352   void writeDILabel(const DILabel *N,
353                     SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
354   void writeDIExpression(const DIExpression *N,
355                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
356   void writeDIGlobalVariableExpression(const DIGlobalVariableExpression *N,
357                                        SmallVectorImpl<uint64_t> &Record,
358                                        unsigned Abbrev);
359   void writeDIObjCProperty(const DIObjCProperty *N,
360                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
361   void writeDIImportedEntity(const DIImportedEntity *N,
362                              SmallVectorImpl<uint64_t> &Record,
363                              unsigned Abbrev);
364   unsigned createNamedMetadataAbbrev();
365   void writeNamedMetadata(SmallVectorImpl<uint64_t> &Record);
366   unsigned createMetadataStringsAbbrev();
367   void writeMetadataStrings(ArrayRef<const Metadata *> Strings,
368                             SmallVectorImpl<uint64_t> &Record);
369   void writeMetadataRecords(ArrayRef<const Metadata *> MDs,
370                             SmallVectorImpl<uint64_t> &Record,
371                             std::vector<unsigned> *MDAbbrevs = nullptr,
372                             std::vector<uint64_t> *IndexPos = nullptr);
373   void writeModuleMetadata();
374   void writeFunctionMetadata(const Function &F);
375   void writeFunctionMetadataAttachment(const Function &F);
376   void 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 (unsigned i = 0, e = Str.size(); i != e; ++i) {
600     if (AbbrevToUse && !BitCodeAbbrevOp::isChar6(Str[i]))
601       AbbrevToUse = 0;
602     Vals.push_back(Str[i]);
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 (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
837     AttributeList AL = Attrs[i];
838     for (unsigned i = AL.index_begin(), e = AL.index_end(); i != e; ++i) {
839       AttributeSet AS = AL.getAttributes(i);
840       if (AS.hasAttributes())
841         Record.push_back(VE.getAttributeGroupID({i, AS}));
842     }
843 
844     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
845     Record.clear();
846   }
847 
848   Stream.ExitBlock();
849 }
850 
851 /// WriteTypeTable - Write out the type table for a module.
852 void ModuleBitcodeWriter::writeTypeTable() {
853   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
854 
855   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
856   SmallVector<uint64_t, 64> TypeVals;
857 
858   uint64_t NumBits = VE.computeBitsRequiredForTypeIndicies();
859 
860   // Abbrev for TYPE_CODE_POINTER.
861   auto Abbv = std::make_shared<BitCodeAbbrev>();
862   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
863   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
864   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
865   unsigned PtrAbbrev = Stream.EmitAbbrev(std::move(Abbv));
866 
867   // Abbrev for TYPE_CODE_OPAQUE_POINTER.
868   Abbv = std::make_shared<BitCodeAbbrev>();
869   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_OPAQUE_POINTER));
870   Abbv->Add(BitCodeAbbrevOp(0)); // Addrspace = 0
871   unsigned OpaquePtrAbbrev = Stream.EmitAbbrev(std::move(Abbv));
872 
873   // Abbrev for TYPE_CODE_FUNCTION.
874   Abbv = std::make_shared<BitCodeAbbrev>();
875   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
876   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
877   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
878   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
879   unsigned FunctionAbbrev = Stream.EmitAbbrev(std::move(Abbv));
880 
881   // Abbrev for TYPE_CODE_STRUCT_ANON.
882   Abbv = std::make_shared<BitCodeAbbrev>();
883   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
884   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
885   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
886   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
887   unsigned StructAnonAbbrev = Stream.EmitAbbrev(std::move(Abbv));
888 
889   // Abbrev for TYPE_CODE_STRUCT_NAME.
890   Abbv = std::make_shared<BitCodeAbbrev>();
891   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
892   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
893   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
894   unsigned StructNameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
895 
896   // Abbrev for TYPE_CODE_STRUCT_NAMED.
897   Abbv = std::make_shared<BitCodeAbbrev>();
898   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
899   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
900   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
901   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
902   unsigned StructNamedAbbrev = Stream.EmitAbbrev(std::move(Abbv));
903 
904   // Abbrev for TYPE_CODE_ARRAY.
905   Abbv = std::make_shared<BitCodeAbbrev>();
906   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
907   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
908   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
909   unsigned ArrayAbbrev = Stream.EmitAbbrev(std::move(Abbv));
910 
911   // Emit an entry count so the reader can reserve space.
912   TypeVals.push_back(TypeList.size());
913   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
914   TypeVals.clear();
915 
916   // Loop over all of the types, emitting each in turn.
917   for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
918     Type *T = TypeList[i];
919     int AbbrevToUse = 0;
920     unsigned Code = 0;
921 
922     switch (T->getTypeID()) {
923     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;      break;
924     case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;      break;
925     case Type::BFloatTyID:    Code = bitc::TYPE_CODE_BFLOAT;    break;
926     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;     break;
927     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE;    break;
928     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80;  break;
929     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128;     break;
930     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
931     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;     break;
932     case Type::MetadataTyID:  Code = bitc::TYPE_CODE_METADATA;  break;
933     case Type::X86_MMXTyID:   Code = bitc::TYPE_CODE_X86_MMX;   break;
934     case Type::X86_AMXTyID:   Code = bitc::TYPE_CODE_X86_AMX;   break;
935     case Type::TokenTyID:     Code = bitc::TYPE_CODE_TOKEN;     break;
936     case Type::IntegerTyID:
937       // INTEGER: [width]
938       Code = bitc::TYPE_CODE_INTEGER;
939       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
940       break;
941     case Type::PointerTyID: {
942       PointerType *PTy = cast<PointerType>(T);
943       unsigned AddressSpace = PTy->getAddressSpace();
944       if (PTy->isOpaque()) {
945         // OPAQUE_POINTER: [address space]
946         Code = bitc::TYPE_CODE_OPAQUE_POINTER;
947         TypeVals.push_back(AddressSpace);
948         if (AddressSpace == 0)
949           AbbrevToUse = OpaquePtrAbbrev;
950       } else {
951         // POINTER: [pointee type, address space]
952         Code = bitc::TYPE_CODE_POINTER;
953         TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
954         TypeVals.push_back(AddressSpace);
955         if (AddressSpace == 0)
956           AbbrevToUse = PtrAbbrev;
957       }
958       break;
959     }
960     case Type::FunctionTyID: {
961       FunctionType *FT = cast<FunctionType>(T);
962       // FUNCTION: [isvararg, retty, paramty x N]
963       Code = bitc::TYPE_CODE_FUNCTION;
964       TypeVals.push_back(FT->isVarArg());
965       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
966       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
967         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
968       AbbrevToUse = FunctionAbbrev;
969       break;
970     }
971     case Type::StructTyID: {
972       StructType *ST = cast<StructType>(T);
973       // STRUCT: [ispacked, eltty x N]
974       TypeVals.push_back(ST->isPacked());
975       // Output all of the element types.
976       for (StructType::element_iterator I = ST->element_begin(),
977            E = ST->element_end(); I != E; ++I)
978         TypeVals.push_back(VE.getTypeID(*I));
979 
980       if (ST->isLiteral()) {
981         Code = bitc::TYPE_CODE_STRUCT_ANON;
982         AbbrevToUse = StructAnonAbbrev;
983       } else {
984         if (ST->isOpaque()) {
985           Code = bitc::TYPE_CODE_OPAQUE;
986         } else {
987           Code = bitc::TYPE_CODE_STRUCT_NAMED;
988           AbbrevToUse = StructNamedAbbrev;
989         }
990 
991         // Emit the name if it is present.
992         if (!ST->getName().empty())
993           writeStringRecord(Stream, bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
994                             StructNameAbbrev);
995       }
996       break;
997     }
998     case Type::ArrayTyID: {
999       ArrayType *AT = cast<ArrayType>(T);
1000       // ARRAY: [numelts, eltty]
1001       Code = bitc::TYPE_CODE_ARRAY;
1002       TypeVals.push_back(AT->getNumElements());
1003       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
1004       AbbrevToUse = ArrayAbbrev;
1005       break;
1006     }
1007     case Type::FixedVectorTyID:
1008     case Type::ScalableVectorTyID: {
1009       VectorType *VT = cast<VectorType>(T);
1010       // VECTOR [numelts, eltty] or
1011       //        [numelts, eltty, scalable]
1012       Code = bitc::TYPE_CODE_VECTOR;
1013       TypeVals.push_back(VT->getElementCount().getKnownMinValue());
1014       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
1015       if (isa<ScalableVectorType>(VT))
1016         TypeVals.push_back(true);
1017       break;
1018     }
1019     }
1020 
1021     // Emit the finished record.
1022     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
1023     TypeVals.clear();
1024   }
1025 
1026   Stream.ExitBlock();
1027 }
1028 
1029 static unsigned getEncodedLinkage(const GlobalValue::LinkageTypes Linkage) {
1030   switch (Linkage) {
1031   case GlobalValue::ExternalLinkage:
1032     return 0;
1033   case GlobalValue::WeakAnyLinkage:
1034     return 16;
1035   case GlobalValue::AppendingLinkage:
1036     return 2;
1037   case GlobalValue::InternalLinkage:
1038     return 3;
1039   case GlobalValue::LinkOnceAnyLinkage:
1040     return 18;
1041   case GlobalValue::ExternalWeakLinkage:
1042     return 7;
1043   case GlobalValue::CommonLinkage:
1044     return 8;
1045   case GlobalValue::PrivateLinkage:
1046     return 9;
1047   case GlobalValue::WeakODRLinkage:
1048     return 17;
1049   case GlobalValue::LinkOnceODRLinkage:
1050     return 19;
1051   case GlobalValue::AvailableExternallyLinkage:
1052     return 12;
1053   }
1054   llvm_unreachable("Invalid linkage");
1055 }
1056 
1057 static unsigned getEncodedLinkage(const GlobalValue &GV) {
1058   return getEncodedLinkage(GV.getLinkage());
1059 }
1060 
1061 static uint64_t getEncodedFFlags(FunctionSummary::FFlags Flags) {
1062   uint64_t RawFlags = 0;
1063   RawFlags |= Flags.ReadNone;
1064   RawFlags |= (Flags.ReadOnly << 1);
1065   RawFlags |= (Flags.NoRecurse << 2);
1066   RawFlags |= (Flags.ReturnDoesNotAlias << 3);
1067   RawFlags |= (Flags.NoInline << 4);
1068   RawFlags |= (Flags.AlwaysInline << 5);
1069   return RawFlags;
1070 }
1071 
1072 // Decode the flags for GlobalValue in the summary. See getDecodedGVSummaryFlags
1073 // in BitcodeReader.cpp.
1074 static uint64_t getEncodedGVSummaryFlags(GlobalValueSummary::GVFlags Flags) {
1075   uint64_t RawFlags = 0;
1076 
1077   RawFlags |= Flags.NotEligibleToImport; // bool
1078   RawFlags |= (Flags.Live << 1);
1079   RawFlags |= (Flags.DSOLocal << 2);
1080   RawFlags |= (Flags.CanAutoHide << 3);
1081 
1082   // Linkage don't need to be remapped at that time for the summary. Any future
1083   // change to the getEncodedLinkage() function will need to be taken into
1084   // account here as well.
1085   RawFlags = (RawFlags << 4) | Flags.Linkage; // 4 bits
1086 
1087   RawFlags |= (Flags.Visibility << 8); // 2 bits
1088 
1089   return RawFlags;
1090 }
1091 
1092 static uint64_t getEncodedGVarFlags(GlobalVarSummary::GVarFlags Flags) {
1093   uint64_t RawFlags = Flags.MaybeReadOnly | (Flags.MaybeWriteOnly << 1) |
1094                       (Flags.Constant << 2) | Flags.VCallVisibility << 3;
1095   return RawFlags;
1096 }
1097 
1098 static unsigned getEncodedVisibility(const GlobalValue &GV) {
1099   switch (GV.getVisibility()) {
1100   case GlobalValue::DefaultVisibility:   return 0;
1101   case GlobalValue::HiddenVisibility:    return 1;
1102   case GlobalValue::ProtectedVisibility: return 2;
1103   }
1104   llvm_unreachable("Invalid visibility");
1105 }
1106 
1107 static unsigned getEncodedDLLStorageClass(const GlobalValue &GV) {
1108   switch (GV.getDLLStorageClass()) {
1109   case GlobalValue::DefaultStorageClass:   return 0;
1110   case GlobalValue::DLLImportStorageClass: return 1;
1111   case GlobalValue::DLLExportStorageClass: return 2;
1112   }
1113   llvm_unreachable("Invalid DLL storage class");
1114 }
1115 
1116 static unsigned getEncodedThreadLocalMode(const GlobalValue &GV) {
1117   switch (GV.getThreadLocalMode()) {
1118     case GlobalVariable::NotThreadLocal:         return 0;
1119     case GlobalVariable::GeneralDynamicTLSModel: return 1;
1120     case GlobalVariable::LocalDynamicTLSModel:   return 2;
1121     case GlobalVariable::InitialExecTLSModel:    return 3;
1122     case GlobalVariable::LocalExecTLSModel:      return 4;
1123   }
1124   llvm_unreachable("Invalid TLS model");
1125 }
1126 
1127 static unsigned getEncodedComdatSelectionKind(const Comdat &C) {
1128   switch (C.getSelectionKind()) {
1129   case Comdat::Any:
1130     return bitc::COMDAT_SELECTION_KIND_ANY;
1131   case Comdat::ExactMatch:
1132     return bitc::COMDAT_SELECTION_KIND_EXACT_MATCH;
1133   case Comdat::Largest:
1134     return bitc::COMDAT_SELECTION_KIND_LARGEST;
1135   case Comdat::NoDeduplicate:
1136     return bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES;
1137   case Comdat::SameSize:
1138     return bitc::COMDAT_SELECTION_KIND_SAME_SIZE;
1139   }
1140   llvm_unreachable("Invalid selection kind");
1141 }
1142 
1143 static unsigned getEncodedUnnamedAddr(const GlobalValue &GV) {
1144   switch (GV.getUnnamedAddr()) {
1145   case GlobalValue::UnnamedAddr::None:   return 0;
1146   case GlobalValue::UnnamedAddr::Local:  return 2;
1147   case GlobalValue::UnnamedAddr::Global: return 1;
1148   }
1149   llvm_unreachable("Invalid unnamed_addr");
1150 }
1151 
1152 size_t ModuleBitcodeWriter::addToStrtab(StringRef Str) {
1153   if (GenerateHash)
1154     Hasher.update(Str);
1155   return StrtabBuilder.add(Str);
1156 }
1157 
1158 void ModuleBitcodeWriter::writeComdats() {
1159   SmallVector<unsigned, 64> Vals;
1160   for (const Comdat *C : VE.getComdats()) {
1161     // COMDAT: [strtab offset, strtab size, selection_kind]
1162     Vals.push_back(addToStrtab(C->getName()));
1163     Vals.push_back(C->getName().size());
1164     Vals.push_back(getEncodedComdatSelectionKind(*C));
1165     Stream.EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
1166     Vals.clear();
1167   }
1168 }
1169 
1170 /// Write a record that will eventually hold the word offset of the
1171 /// module-level VST. For now the offset is 0, which will be backpatched
1172 /// after the real VST is written. Saves the bit offset to backpatch.
1173 void ModuleBitcodeWriter::writeValueSymbolTableForwardDecl() {
1174   // Write a placeholder value in for the offset of the real VST,
1175   // which is written after the function blocks so that it can include
1176   // the offset of each function. The placeholder offset will be
1177   // updated when the real VST is written.
1178   auto Abbv = std::make_shared<BitCodeAbbrev>();
1179   Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_VSTOFFSET));
1180   // Blocks are 32-bit aligned, so we can use a 32-bit word offset to
1181   // hold the real VST offset. Must use fixed instead of VBR as we don't
1182   // know how many VBR chunks to reserve ahead of time.
1183   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
1184   unsigned VSTOffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1185 
1186   // Emit the placeholder
1187   uint64_t Vals[] = {bitc::MODULE_CODE_VSTOFFSET, 0};
1188   Stream.EmitRecordWithAbbrev(VSTOffsetAbbrev, Vals);
1189 
1190   // Compute and save the bit offset to the placeholder, which will be
1191   // patched when the real VST is written. We can simply subtract the 32-bit
1192   // fixed size from the current bit number to get the location to backpatch.
1193   VSTOffsetPlaceholder = Stream.GetCurrentBitNo() - 32;
1194 }
1195 
1196 enum StringEncoding { SE_Char6, SE_Fixed7, SE_Fixed8 };
1197 
1198 /// Determine the encoding to use for the given string name and length.
1199 static StringEncoding getStringEncoding(StringRef Str) {
1200   bool isChar6 = true;
1201   for (char C : Str) {
1202     if (isChar6)
1203       isChar6 = BitCodeAbbrevOp::isChar6(C);
1204     if ((unsigned char)C & 128)
1205       // don't bother scanning the rest.
1206       return SE_Fixed8;
1207   }
1208   if (isChar6)
1209     return SE_Char6;
1210   return SE_Fixed7;
1211 }
1212 
1213 /// Emit top-level description of module, including target triple, inline asm,
1214 /// descriptors for global variables, and function prototype info.
1215 /// Returns the bit offset to backpatch with the location of the real VST.
1216 void ModuleBitcodeWriter::writeModuleInfo() {
1217   // Emit various pieces of data attached to a module.
1218   if (!M.getTargetTriple().empty())
1219     writeStringRecord(Stream, bitc::MODULE_CODE_TRIPLE, M.getTargetTriple(),
1220                       0 /*TODO*/);
1221   const std::string &DL = M.getDataLayoutStr();
1222   if (!DL.empty())
1223     writeStringRecord(Stream, bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/);
1224   if (!M.getModuleInlineAsm().empty())
1225     writeStringRecord(Stream, bitc::MODULE_CODE_ASM, M.getModuleInlineAsm(),
1226                       0 /*TODO*/);
1227 
1228   // Emit information about sections and GC, computing how many there are. Also
1229   // compute the maximum alignment value.
1230   std::map<std::string, unsigned> SectionMap;
1231   std::map<std::string, unsigned> GCMap;
1232   MaybeAlign MaxAlignment;
1233   unsigned MaxGlobalType = 0;
1234   const auto UpdateMaxAlignment = [&MaxAlignment](const MaybeAlign A) {
1235     if (A)
1236       MaxAlignment = !MaxAlignment ? *A : std::max(*MaxAlignment, *A);
1237   };
1238   for (const GlobalVariable &GV : M.globals()) {
1239     UpdateMaxAlignment(GV.getAlign());
1240     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getValueType()));
1241     if (GV.hasSection()) {
1242       // Give section names unique ID's.
1243       unsigned &Entry = SectionMap[std::string(GV.getSection())];
1244       if (!Entry) {
1245         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
1246                           0 /*TODO*/);
1247         Entry = SectionMap.size();
1248       }
1249     }
1250   }
1251   for (const Function &F : M) {
1252     UpdateMaxAlignment(F.getAlign());
1253     if (F.hasSection()) {
1254       // Give section names unique ID's.
1255       unsigned &Entry = SectionMap[std::string(F.getSection())];
1256       if (!Entry) {
1257         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
1258                           0 /*TODO*/);
1259         Entry = SectionMap.size();
1260       }
1261     }
1262     if (F.hasGC()) {
1263       // Same for GC names.
1264       unsigned &Entry = GCMap[F.getGC()];
1265       if (!Entry) {
1266         writeStringRecord(Stream, bitc::MODULE_CODE_GCNAME, F.getGC(),
1267                           0 /*TODO*/);
1268         Entry = GCMap.size();
1269       }
1270     }
1271   }
1272 
1273   // Emit abbrev for globals, now that we know # sections and max alignment.
1274   unsigned SimpleGVarAbbrev = 0;
1275   if (!M.global_empty()) {
1276     // Add an abbrev for common globals with no visibility or thread localness.
1277     auto Abbv = std::make_shared<BitCodeAbbrev>();
1278     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
1279     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1280     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1281     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1282                               Log2_32_Ceil(MaxGlobalType+1)));
1283     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddrSpace << 2
1284                                                            //| explicitType << 1
1285                                                            //| constant
1286     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Initializer.
1287     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // Linkage.
1288     if (!MaxAlignment)                                     // Alignment.
1289       Abbv->Add(BitCodeAbbrevOp(0));
1290     else {
1291       unsigned MaxEncAlignment = getEncodedAlign(MaxAlignment);
1292       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1293                                Log2_32_Ceil(MaxEncAlignment+1)));
1294     }
1295     if (SectionMap.empty())                                    // Section.
1296       Abbv->Add(BitCodeAbbrevOp(0));
1297     else
1298       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1299                                Log2_32_Ceil(SectionMap.size()+1)));
1300     // Don't bother emitting vis + thread local.
1301     SimpleGVarAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1302   }
1303 
1304   SmallVector<unsigned, 64> Vals;
1305   // Emit the module's source file name.
1306   {
1307     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
1308     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
1309     if (Bits == SE_Char6)
1310       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
1311     else if (Bits == SE_Fixed7)
1312       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
1313 
1314     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
1315     auto Abbv = std::make_shared<BitCodeAbbrev>();
1316     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
1317     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1318     Abbv->Add(AbbrevOpToUse);
1319     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1320 
1321     for (const auto P : M.getSourceFileName())
1322       Vals.push_back((unsigned char)P);
1323 
1324     // Emit the finished record.
1325     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
1326     Vals.clear();
1327   }
1328 
1329   // Emit the global variable information.
1330   for (const GlobalVariable &GV : M.globals()) {
1331     unsigned AbbrevToUse = 0;
1332 
1333     // GLOBALVAR: [strtab offset, strtab size, type, isconst, initid,
1334     //             linkage, alignment, section, visibility, threadlocal,
1335     //             unnamed_addr, externally_initialized, dllstorageclass,
1336     //             comdat, attributes, DSO_Local]
1337     Vals.push_back(addToStrtab(GV.getName()));
1338     Vals.push_back(GV.getName().size());
1339     Vals.push_back(VE.getTypeID(GV.getValueType()));
1340     Vals.push_back(GV.getType()->getAddressSpace() << 2 | 2 | GV.isConstant());
1341     Vals.push_back(GV.isDeclaration() ? 0 :
1342                    (VE.getValueID(GV.getInitializer()) + 1));
1343     Vals.push_back(getEncodedLinkage(GV));
1344     Vals.push_back(getEncodedAlign(GV.getAlign()));
1345     Vals.push_back(GV.hasSection() ? SectionMap[std::string(GV.getSection())]
1346                                    : 0);
1347     if (GV.isThreadLocal() ||
1348         GV.getVisibility() != GlobalValue::DefaultVisibility ||
1349         GV.getUnnamedAddr() != GlobalValue::UnnamedAddr::None ||
1350         GV.isExternallyInitialized() ||
1351         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
1352         GV.hasComdat() ||
1353         GV.hasAttributes() ||
1354         GV.isDSOLocal() ||
1355         GV.hasPartition()) {
1356       Vals.push_back(getEncodedVisibility(GV));
1357       Vals.push_back(getEncodedThreadLocalMode(GV));
1358       Vals.push_back(getEncodedUnnamedAddr(GV));
1359       Vals.push_back(GV.isExternallyInitialized());
1360       Vals.push_back(getEncodedDLLStorageClass(GV));
1361       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
1362 
1363       auto AL = GV.getAttributesAsList(AttributeList::FunctionIndex);
1364       Vals.push_back(VE.getAttributeListID(AL));
1365 
1366       Vals.push_back(GV.isDSOLocal());
1367       Vals.push_back(addToStrtab(GV.getPartition()));
1368       Vals.push_back(GV.getPartition().size());
1369     } else {
1370       AbbrevToUse = SimpleGVarAbbrev;
1371     }
1372 
1373     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
1374     Vals.clear();
1375   }
1376 
1377   // Emit the function proto information.
1378   for (const Function &F : M) {
1379     // FUNCTION:  [strtab offset, strtab size, type, callingconv, isproto,
1380     //             linkage, paramattrs, alignment, section, visibility, gc,
1381     //             unnamed_addr, prologuedata, dllstorageclass, comdat,
1382     //             prefixdata, personalityfn, DSO_Local, addrspace]
1383     Vals.push_back(addToStrtab(F.getName()));
1384     Vals.push_back(F.getName().size());
1385     Vals.push_back(VE.getTypeID(F.getFunctionType()));
1386     Vals.push_back(F.getCallingConv());
1387     Vals.push_back(F.isDeclaration());
1388     Vals.push_back(getEncodedLinkage(F));
1389     Vals.push_back(VE.getAttributeListID(F.getAttributes()));
1390     Vals.push_back(getEncodedAlign(F.getAlign()));
1391     Vals.push_back(F.hasSection() ? SectionMap[std::string(F.getSection())]
1392                                   : 0);
1393     Vals.push_back(getEncodedVisibility(F));
1394     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
1395     Vals.push_back(getEncodedUnnamedAddr(F));
1396     Vals.push_back(F.hasPrologueData() ? (VE.getValueID(F.getPrologueData()) + 1)
1397                                        : 0);
1398     Vals.push_back(getEncodedDLLStorageClass(F));
1399     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
1400     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
1401                                      : 0);
1402     Vals.push_back(
1403         F.hasPersonalityFn() ? (VE.getValueID(F.getPersonalityFn()) + 1) : 0);
1404 
1405     Vals.push_back(F.isDSOLocal());
1406     Vals.push_back(F.getAddressSpace());
1407     Vals.push_back(addToStrtab(F.getPartition()));
1408     Vals.push_back(F.getPartition().size());
1409 
1410     unsigned AbbrevToUse = 0;
1411     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
1412     Vals.clear();
1413   }
1414 
1415   // Emit the alias information.
1416   for (const GlobalAlias &A : M.aliases()) {
1417     // ALIAS: [strtab offset, strtab size, alias type, aliasee val#, linkage,
1418     //         visibility, dllstorageclass, threadlocal, unnamed_addr,
1419     //         DSO_Local]
1420     Vals.push_back(addToStrtab(A.getName()));
1421     Vals.push_back(A.getName().size());
1422     Vals.push_back(VE.getTypeID(A.getValueType()));
1423     Vals.push_back(A.getType()->getAddressSpace());
1424     Vals.push_back(VE.getValueID(A.getAliasee()));
1425     Vals.push_back(getEncodedLinkage(A));
1426     Vals.push_back(getEncodedVisibility(A));
1427     Vals.push_back(getEncodedDLLStorageClass(A));
1428     Vals.push_back(getEncodedThreadLocalMode(A));
1429     Vals.push_back(getEncodedUnnamedAddr(A));
1430     Vals.push_back(A.isDSOLocal());
1431     Vals.push_back(addToStrtab(A.getPartition()));
1432     Vals.push_back(A.getPartition().size());
1433 
1434     unsigned AbbrevToUse = 0;
1435     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
1436     Vals.clear();
1437   }
1438 
1439   // Emit the ifunc information.
1440   for (const GlobalIFunc &I : M.ifuncs()) {
1441     // IFUNC: [strtab offset, strtab size, ifunc type, address space, resolver
1442     //         val#, linkage, visibility, DSO_Local]
1443     Vals.push_back(addToStrtab(I.getName()));
1444     Vals.push_back(I.getName().size());
1445     Vals.push_back(VE.getTypeID(I.getValueType()));
1446     Vals.push_back(I.getType()->getAddressSpace());
1447     Vals.push_back(VE.getValueID(I.getResolver()));
1448     Vals.push_back(getEncodedLinkage(I));
1449     Vals.push_back(getEncodedVisibility(I));
1450     Vals.push_back(I.isDSOLocal());
1451     Vals.push_back(addToStrtab(I.getPartition()));
1452     Vals.push_back(I.getPartition().size());
1453     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
1454     Vals.clear();
1455   }
1456 
1457   writeValueSymbolTableForwardDecl();
1458 }
1459 
1460 static uint64_t getOptimizationFlags(const Value *V) {
1461   uint64_t Flags = 0;
1462 
1463   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
1464     if (OBO->hasNoSignedWrap())
1465       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
1466     if (OBO->hasNoUnsignedWrap())
1467       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
1468   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
1469     if (PEO->isExact())
1470       Flags |= 1 << bitc::PEO_EXACT;
1471   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
1472     if (FPMO->hasAllowReassoc())
1473       Flags |= bitc::AllowReassoc;
1474     if (FPMO->hasNoNaNs())
1475       Flags |= bitc::NoNaNs;
1476     if (FPMO->hasNoInfs())
1477       Flags |= bitc::NoInfs;
1478     if (FPMO->hasNoSignedZeros())
1479       Flags |= bitc::NoSignedZeros;
1480     if (FPMO->hasAllowReciprocal())
1481       Flags |= bitc::AllowReciprocal;
1482     if (FPMO->hasAllowContract())
1483       Flags |= bitc::AllowContract;
1484     if (FPMO->hasApproxFunc())
1485       Flags |= bitc::ApproxFunc;
1486   }
1487 
1488   return Flags;
1489 }
1490 
1491 void ModuleBitcodeWriter::writeValueAsMetadata(
1492     const ValueAsMetadata *MD, SmallVectorImpl<uint64_t> &Record) {
1493   // Mimic an MDNode with a value as one operand.
1494   Value *V = MD->getValue();
1495   Record.push_back(VE.getTypeID(V->getType()));
1496   Record.push_back(VE.getValueID(V));
1497   Stream.EmitRecord(bitc::METADATA_VALUE, Record, 0);
1498   Record.clear();
1499 }
1500 
1501 void ModuleBitcodeWriter::writeMDTuple(const MDTuple *N,
1502                                        SmallVectorImpl<uint64_t> &Record,
1503                                        unsigned Abbrev) {
1504   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
1505     Metadata *MD = N->getOperand(i);
1506     assert(!(MD && isa<LocalAsMetadata>(MD)) &&
1507            "Unexpected function-local metadata");
1508     Record.push_back(VE.getMetadataOrNullID(MD));
1509   }
1510   Stream.EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
1511                                     : bitc::METADATA_NODE,
1512                     Record, Abbrev);
1513   Record.clear();
1514 }
1515 
1516 unsigned ModuleBitcodeWriter::createDILocationAbbrev() {
1517   // Assume the column is usually under 128, and always output the inlined-at
1518   // location (it's never more expensive than building an array size 1).
1519   auto Abbv = std::make_shared<BitCodeAbbrev>();
1520   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
1521   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1522   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1523   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1524   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1525   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1526   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1527   return Stream.EmitAbbrev(std::move(Abbv));
1528 }
1529 
1530 void ModuleBitcodeWriter::writeDILocation(const DILocation *N,
1531                                           SmallVectorImpl<uint64_t> &Record,
1532                                           unsigned &Abbrev) {
1533   if (!Abbrev)
1534     Abbrev = createDILocationAbbrev();
1535 
1536   Record.push_back(N->isDistinct());
1537   Record.push_back(N->getLine());
1538   Record.push_back(N->getColumn());
1539   Record.push_back(VE.getMetadataID(N->getScope()));
1540   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
1541   Record.push_back(N->isImplicitCode());
1542 
1543   Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
1544   Record.clear();
1545 }
1546 
1547 unsigned ModuleBitcodeWriter::createGenericDINodeAbbrev() {
1548   // Assume the column is usually under 128, and always output the inlined-at
1549   // location (it's never more expensive than building an array size 1).
1550   auto Abbv = std::make_shared<BitCodeAbbrev>();
1551   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
1552   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1553   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1554   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1555   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1556   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1557   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1558   return Stream.EmitAbbrev(std::move(Abbv));
1559 }
1560 
1561 void ModuleBitcodeWriter::writeGenericDINode(const GenericDINode *N,
1562                                              SmallVectorImpl<uint64_t> &Record,
1563                                              unsigned &Abbrev) {
1564   if (!Abbrev)
1565     Abbrev = createGenericDINodeAbbrev();
1566 
1567   Record.push_back(N->isDistinct());
1568   Record.push_back(N->getTag());
1569   Record.push_back(0); // Per-tag version field; unused for now.
1570 
1571   for (auto &I : N->operands())
1572     Record.push_back(VE.getMetadataOrNullID(I));
1573 
1574   Stream.EmitRecord(bitc::METADATA_GENERIC_DEBUG, Record, Abbrev);
1575   Record.clear();
1576 }
1577 
1578 void ModuleBitcodeWriter::writeDISubrange(const DISubrange *N,
1579                                           SmallVectorImpl<uint64_t> &Record,
1580                                           unsigned Abbrev) {
1581   const uint64_t Version = 2 << 1;
1582   Record.push_back((uint64_t)N->isDistinct() | Version);
1583   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1584   Record.push_back(VE.getMetadataOrNullID(N->getRawLowerBound()));
1585   Record.push_back(VE.getMetadataOrNullID(N->getRawUpperBound()));
1586   Record.push_back(VE.getMetadataOrNullID(N->getRawStride()));
1587 
1588   Stream.EmitRecord(bitc::METADATA_SUBRANGE, Record, Abbrev);
1589   Record.clear();
1590 }
1591 
1592 void ModuleBitcodeWriter::writeDIGenericSubrange(
1593     const DIGenericSubrange *N, SmallVectorImpl<uint64_t> &Record,
1594     unsigned Abbrev) {
1595   Record.push_back((uint64_t)N->isDistinct());
1596   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1597   Record.push_back(VE.getMetadataOrNullID(N->getRawLowerBound()));
1598   Record.push_back(VE.getMetadataOrNullID(N->getRawUpperBound()));
1599   Record.push_back(VE.getMetadataOrNullID(N->getRawStride()));
1600 
1601   Stream.EmitRecord(bitc::METADATA_GENERIC_SUBRANGE, Record, Abbrev);
1602   Record.clear();
1603 }
1604 
1605 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
1606   if ((int64_t)V >= 0)
1607     Vals.push_back(V << 1);
1608   else
1609     Vals.push_back((-V << 1) | 1);
1610 }
1611 
1612 static void emitWideAPInt(SmallVectorImpl<uint64_t> &Vals, const APInt &A) {
1613   // We have an arbitrary precision integer value to write whose
1614   // bit width is > 64. However, in canonical unsigned integer
1615   // format it is likely that the high bits are going to be zero.
1616   // So, we only write the number of active words.
1617   unsigned NumWords = A.getActiveWords();
1618   const uint64_t *RawData = A.getRawData();
1619   for (unsigned i = 0; i < NumWords; i++)
1620     emitSignedInt64(Vals, RawData[i]);
1621 }
1622 
1623 void ModuleBitcodeWriter::writeDIEnumerator(const DIEnumerator *N,
1624                                             SmallVectorImpl<uint64_t> &Record,
1625                                             unsigned Abbrev) {
1626   const uint64_t IsBigInt = 1 << 2;
1627   Record.push_back(IsBigInt | (N->isUnsigned() << 1) | N->isDistinct());
1628   Record.push_back(N->getValue().getBitWidth());
1629   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1630   emitWideAPInt(Record, N->getValue());
1631 
1632   Stream.EmitRecord(bitc::METADATA_ENUMERATOR, Record, Abbrev);
1633   Record.clear();
1634 }
1635 
1636 void ModuleBitcodeWriter::writeDIBasicType(const DIBasicType *N,
1637                                            SmallVectorImpl<uint64_t> &Record,
1638                                            unsigned Abbrev) {
1639   Record.push_back(N->isDistinct());
1640   Record.push_back(N->getTag());
1641   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1642   Record.push_back(N->getSizeInBits());
1643   Record.push_back(N->getAlignInBits());
1644   Record.push_back(N->getEncoding());
1645   Record.push_back(N->getFlags());
1646 
1647   Stream.EmitRecord(bitc::METADATA_BASIC_TYPE, Record, Abbrev);
1648   Record.clear();
1649 }
1650 
1651 void ModuleBitcodeWriter::writeDIStringType(const DIStringType *N,
1652                                             SmallVectorImpl<uint64_t> &Record,
1653                                             unsigned Abbrev) {
1654   Record.push_back(N->isDistinct());
1655   Record.push_back(N->getTag());
1656   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1657   Record.push_back(VE.getMetadataOrNullID(N->getStringLength()));
1658   Record.push_back(VE.getMetadataOrNullID(N->getStringLengthExp()));
1659   Record.push_back(N->getSizeInBits());
1660   Record.push_back(N->getAlignInBits());
1661   Record.push_back(N->getEncoding());
1662 
1663   Stream.EmitRecord(bitc::METADATA_STRING_TYPE, Record, Abbrev);
1664   Record.clear();
1665 }
1666 
1667 void ModuleBitcodeWriter::writeDIDerivedType(const DIDerivedType *N,
1668                                              SmallVectorImpl<uint64_t> &Record,
1669                                              unsigned Abbrev) {
1670   Record.push_back(N->isDistinct());
1671   Record.push_back(N->getTag());
1672   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1673   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1674   Record.push_back(N->getLine());
1675   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1676   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1677   Record.push_back(N->getSizeInBits());
1678   Record.push_back(N->getAlignInBits());
1679   Record.push_back(N->getOffsetInBits());
1680   Record.push_back(N->getFlags());
1681   Record.push_back(VE.getMetadataOrNullID(N->getExtraData()));
1682 
1683   // DWARF address space is encoded as N->getDWARFAddressSpace() + 1. 0 means
1684   // that there is no DWARF address space associated with DIDerivedType.
1685   if (const auto &DWARFAddressSpace = N->getDWARFAddressSpace())
1686     Record.push_back(*DWARFAddressSpace + 1);
1687   else
1688     Record.push_back(0);
1689 
1690   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1691 
1692   Stream.EmitRecord(bitc::METADATA_DERIVED_TYPE, Record, Abbrev);
1693   Record.clear();
1694 }
1695 
1696 void ModuleBitcodeWriter::writeDICompositeType(
1697     const DICompositeType *N, SmallVectorImpl<uint64_t> &Record,
1698     unsigned Abbrev) {
1699   const unsigned IsNotUsedInOldTypeRef = 0x2;
1700   Record.push_back(IsNotUsedInOldTypeRef | (unsigned)N->isDistinct());
1701   Record.push_back(N->getTag());
1702   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1703   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1704   Record.push_back(N->getLine());
1705   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1706   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1707   Record.push_back(N->getSizeInBits());
1708   Record.push_back(N->getAlignInBits());
1709   Record.push_back(N->getOffsetInBits());
1710   Record.push_back(N->getFlags());
1711   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1712   Record.push_back(N->getRuntimeLang());
1713   Record.push_back(VE.getMetadataOrNullID(N->getVTableHolder()));
1714   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1715   Record.push_back(VE.getMetadataOrNullID(N->getRawIdentifier()));
1716   Record.push_back(VE.getMetadataOrNullID(N->getDiscriminator()));
1717   Record.push_back(VE.getMetadataOrNullID(N->getRawDataLocation()));
1718   Record.push_back(VE.getMetadataOrNullID(N->getRawAssociated()));
1719   Record.push_back(VE.getMetadataOrNullID(N->getRawAllocated()));
1720   Record.push_back(VE.getMetadataOrNullID(N->getRawRank()));
1721   Record.push_back(VE.getMetadataOrNullID(N->getAnnotations().get()));
1722 
1723   Stream.EmitRecord(bitc::METADATA_COMPOSITE_TYPE, Record, Abbrev);
1724   Record.clear();
1725 }
1726 
1727 void ModuleBitcodeWriter::writeDISubroutineType(
1728     const DISubroutineType *N, SmallVectorImpl<uint64_t> &Record,
1729     unsigned Abbrev) {
1730   const unsigned HasNoOldTypeRefs = 0x2;
1731   Record.push_back(HasNoOldTypeRefs | (unsigned)N->isDistinct());
1732   Record.push_back(N->getFlags());
1733   Record.push_back(VE.getMetadataOrNullID(N->getTypeArray().get()));
1734   Record.push_back(N->getCC());
1735 
1736   Stream.EmitRecord(bitc::METADATA_SUBROUTINE_TYPE, Record, Abbrev);
1737   Record.clear();
1738 }
1739 
1740 void ModuleBitcodeWriter::writeDIFile(const DIFile *N,
1741                                       SmallVectorImpl<uint64_t> &Record,
1742                                       unsigned Abbrev) {
1743   Record.push_back(N->isDistinct());
1744   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
1745   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
1746   if (N->getRawChecksum()) {
1747     Record.push_back(N->getRawChecksum()->Kind);
1748     Record.push_back(VE.getMetadataOrNullID(N->getRawChecksum()->Value));
1749   } else {
1750     // Maintain backwards compatibility with the old internal representation of
1751     // CSK_None in ChecksumKind by writing nulls here when Checksum is None.
1752     Record.push_back(0);
1753     Record.push_back(VE.getMetadataOrNullID(nullptr));
1754   }
1755   auto Source = N->getRawSource();
1756   if (Source)
1757     Record.push_back(VE.getMetadataOrNullID(*Source));
1758 
1759   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
1760   Record.clear();
1761 }
1762 
1763 void ModuleBitcodeWriter::writeDICompileUnit(const DICompileUnit *N,
1764                                              SmallVectorImpl<uint64_t> &Record,
1765                                              unsigned Abbrev) {
1766   assert(N->isDistinct() && "Expected distinct compile units");
1767   Record.push_back(/* IsDistinct */ true);
1768   Record.push_back(N->getSourceLanguage());
1769   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1770   Record.push_back(VE.getMetadataOrNullID(N->getRawProducer()));
1771   Record.push_back(N->isOptimized());
1772   Record.push_back(VE.getMetadataOrNullID(N->getRawFlags()));
1773   Record.push_back(N->getRuntimeVersion());
1774   Record.push_back(VE.getMetadataOrNullID(N->getRawSplitDebugFilename()));
1775   Record.push_back(N->getEmissionKind());
1776   Record.push_back(VE.getMetadataOrNullID(N->getEnumTypes().get()));
1777   Record.push_back(VE.getMetadataOrNullID(N->getRetainedTypes().get()));
1778   Record.push_back(/* subprograms */ 0);
1779   Record.push_back(VE.getMetadataOrNullID(N->getGlobalVariables().get()));
1780   Record.push_back(VE.getMetadataOrNullID(N->getImportedEntities().get()));
1781   Record.push_back(N->getDWOId());
1782   Record.push_back(VE.getMetadataOrNullID(N->getMacros().get()));
1783   Record.push_back(N->getSplitDebugInlining());
1784   Record.push_back(N->getDebugInfoForProfiling());
1785   Record.push_back((unsigned)N->getNameTableKind());
1786   Record.push_back(N->getRangesBaseAddress());
1787   Record.push_back(VE.getMetadataOrNullID(N->getRawSysRoot()));
1788   Record.push_back(VE.getMetadataOrNullID(N->getRawSDK()));
1789 
1790   Stream.EmitRecord(bitc::METADATA_COMPILE_UNIT, Record, Abbrev);
1791   Record.clear();
1792 }
1793 
1794 void ModuleBitcodeWriter::writeDISubprogram(const DISubprogram *N,
1795                                             SmallVectorImpl<uint64_t> &Record,
1796                                             unsigned Abbrev) {
1797   const uint64_t HasUnitFlag = 1 << 1;
1798   const uint64_t HasSPFlagsFlag = 1 << 2;
1799   Record.push_back(uint64_t(N->isDistinct()) | HasUnitFlag | HasSPFlagsFlag);
1800   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1801   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1802   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1803   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1804   Record.push_back(N->getLine());
1805   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1806   Record.push_back(N->getScopeLine());
1807   Record.push_back(VE.getMetadataOrNullID(N->getContainingType()));
1808   Record.push_back(N->getSPFlags());
1809   Record.push_back(N->getVirtualIndex());
1810   Record.push_back(N->getFlags());
1811   Record.push_back(VE.getMetadataOrNullID(N->getRawUnit()));
1812   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1813   Record.push_back(VE.getMetadataOrNullID(N->getDeclaration()));
1814   Record.push_back(VE.getMetadataOrNullID(N->getRetainedNodes().get()));
1815   Record.push_back(N->getThisAdjustment());
1816   Record.push_back(VE.getMetadataOrNullID(N->getThrownTypes().get()));
1817 
1818   Stream.EmitRecord(bitc::METADATA_SUBPROGRAM, Record, Abbrev);
1819   Record.clear();
1820 }
1821 
1822 void ModuleBitcodeWriter::writeDILexicalBlock(const DILexicalBlock *N,
1823                                               SmallVectorImpl<uint64_t> &Record,
1824                                               unsigned Abbrev) {
1825   Record.push_back(N->isDistinct());
1826   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1827   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1828   Record.push_back(N->getLine());
1829   Record.push_back(N->getColumn());
1830 
1831   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK, Record, Abbrev);
1832   Record.clear();
1833 }
1834 
1835 void ModuleBitcodeWriter::writeDILexicalBlockFile(
1836     const DILexicalBlockFile *N, SmallVectorImpl<uint64_t> &Record,
1837     unsigned Abbrev) {
1838   Record.push_back(N->isDistinct());
1839   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1840   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1841   Record.push_back(N->getDiscriminator());
1842 
1843   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK_FILE, Record, Abbrev);
1844   Record.clear();
1845 }
1846 
1847 void ModuleBitcodeWriter::writeDICommonBlock(const DICommonBlock *N,
1848                                              SmallVectorImpl<uint64_t> &Record,
1849                                              unsigned Abbrev) {
1850   Record.push_back(N->isDistinct());
1851   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1852   Record.push_back(VE.getMetadataOrNullID(N->getDecl()));
1853   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1854   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1855   Record.push_back(N->getLineNo());
1856 
1857   Stream.EmitRecord(bitc::METADATA_COMMON_BLOCK, Record, Abbrev);
1858   Record.clear();
1859 }
1860 
1861 void ModuleBitcodeWriter::writeDINamespace(const DINamespace *N,
1862                                            SmallVectorImpl<uint64_t> &Record,
1863                                            unsigned Abbrev) {
1864   Record.push_back(N->isDistinct() | N->getExportSymbols() << 1);
1865   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1866   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1867 
1868   Stream.EmitRecord(bitc::METADATA_NAMESPACE, Record, Abbrev);
1869   Record.clear();
1870 }
1871 
1872 void ModuleBitcodeWriter::writeDIMacro(const DIMacro *N,
1873                                        SmallVectorImpl<uint64_t> &Record,
1874                                        unsigned Abbrev) {
1875   Record.push_back(N->isDistinct());
1876   Record.push_back(N->getMacinfoType());
1877   Record.push_back(N->getLine());
1878   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1879   Record.push_back(VE.getMetadataOrNullID(N->getRawValue()));
1880 
1881   Stream.EmitRecord(bitc::METADATA_MACRO, Record, Abbrev);
1882   Record.clear();
1883 }
1884 
1885 void ModuleBitcodeWriter::writeDIMacroFile(const DIMacroFile *N,
1886                                            SmallVectorImpl<uint64_t> &Record,
1887                                            unsigned Abbrev) {
1888   Record.push_back(N->isDistinct());
1889   Record.push_back(N->getMacinfoType());
1890   Record.push_back(N->getLine());
1891   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1892   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1893 
1894   Stream.EmitRecord(bitc::METADATA_MACRO_FILE, Record, Abbrev);
1895   Record.clear();
1896 }
1897 
1898 void ModuleBitcodeWriter::writeDIArgList(const DIArgList *N,
1899                                          SmallVectorImpl<uint64_t> &Record,
1900                                          unsigned Abbrev) {
1901   Record.reserve(N->getArgs().size());
1902   for (ValueAsMetadata *MD : N->getArgs())
1903     Record.push_back(VE.getMetadataID(MD));
1904 
1905   Stream.EmitRecord(bitc::METADATA_ARG_LIST, Record, Abbrev);
1906   Record.clear();
1907 }
1908 
1909 void ModuleBitcodeWriter::writeDIModule(const DIModule *N,
1910                                         SmallVectorImpl<uint64_t> &Record,
1911                                         unsigned Abbrev) {
1912   Record.push_back(N->isDistinct());
1913   for (auto &I : N->operands())
1914     Record.push_back(VE.getMetadataOrNullID(I));
1915   Record.push_back(N->getLineNo());
1916   Record.push_back(N->getIsDecl());
1917 
1918   Stream.EmitRecord(bitc::METADATA_MODULE, Record, Abbrev);
1919   Record.clear();
1920 }
1921 
1922 void ModuleBitcodeWriter::writeDITemplateTypeParameter(
1923     const DITemplateTypeParameter *N, SmallVectorImpl<uint64_t> &Record,
1924     unsigned Abbrev) {
1925   Record.push_back(N->isDistinct());
1926   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1927   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1928   Record.push_back(N->isDefault());
1929 
1930   Stream.EmitRecord(bitc::METADATA_TEMPLATE_TYPE, Record, Abbrev);
1931   Record.clear();
1932 }
1933 
1934 void ModuleBitcodeWriter::writeDITemplateValueParameter(
1935     const DITemplateValueParameter *N, SmallVectorImpl<uint64_t> &Record,
1936     unsigned Abbrev) {
1937   Record.push_back(N->isDistinct());
1938   Record.push_back(N->getTag());
1939   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1940   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1941   Record.push_back(N->isDefault());
1942   Record.push_back(VE.getMetadataOrNullID(N->getValue()));
1943 
1944   Stream.EmitRecord(bitc::METADATA_TEMPLATE_VALUE, Record, Abbrev);
1945   Record.clear();
1946 }
1947 
1948 void ModuleBitcodeWriter::writeDIGlobalVariable(
1949     const DIGlobalVariable *N, SmallVectorImpl<uint64_t> &Record,
1950     unsigned Abbrev) {
1951   const uint64_t Version = 2 << 1;
1952   Record.push_back((uint64_t)N->isDistinct() | Version);
1953   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1954   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1955   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1956   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1957   Record.push_back(N->getLine());
1958   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1959   Record.push_back(N->isLocalToUnit());
1960   Record.push_back(N->isDefinition());
1961   Record.push_back(VE.getMetadataOrNullID(N->getStaticDataMemberDeclaration()));
1962   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams()));
1963   Record.push_back(N->getAlignInBits());
1964 
1965   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR, Record, Abbrev);
1966   Record.clear();
1967 }
1968 
1969 void ModuleBitcodeWriter::writeDILocalVariable(
1970     const DILocalVariable *N, SmallVectorImpl<uint64_t> &Record,
1971     unsigned Abbrev) {
1972   // In order to support all possible bitcode formats in BitcodeReader we need
1973   // to distinguish the following cases:
1974   // 1) Record has no artificial tag (Record[1]),
1975   //   has no obsolete inlinedAt field (Record[9]).
1976   //   In this case Record size will be 8, HasAlignment flag is false.
1977   // 2) Record has artificial tag (Record[1]),
1978   //   has no obsolete inlignedAt field (Record[9]).
1979   //   In this case Record size will be 9, HasAlignment flag is false.
1980   // 3) Record has both artificial tag (Record[1]) and
1981   //   obsolete inlignedAt field (Record[9]).
1982   //   In this case Record size will be 10, HasAlignment flag is false.
1983   // 4) Record has neither artificial tag, nor inlignedAt field, but
1984   //   HasAlignment flag is true and Record[8] contains alignment value.
1985   const uint64_t HasAlignmentFlag = 1 << 1;
1986   Record.push_back((uint64_t)N->isDistinct() | HasAlignmentFlag);
1987   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1988   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1989   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1990   Record.push_back(N->getLine());
1991   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1992   Record.push_back(N->getArg());
1993   Record.push_back(N->getFlags());
1994   Record.push_back(N->getAlignInBits());
1995 
1996   Stream.EmitRecord(bitc::METADATA_LOCAL_VAR, Record, Abbrev);
1997   Record.clear();
1998 }
1999 
2000 void ModuleBitcodeWriter::writeDILabel(
2001     const DILabel *N, SmallVectorImpl<uint64_t> &Record,
2002     unsigned Abbrev) {
2003   Record.push_back((uint64_t)N->isDistinct());
2004   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2005   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2006   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2007   Record.push_back(N->getLine());
2008 
2009   Stream.EmitRecord(bitc::METADATA_LABEL, Record, Abbrev);
2010   Record.clear();
2011 }
2012 
2013 void ModuleBitcodeWriter::writeDIExpression(const DIExpression *N,
2014                                             SmallVectorImpl<uint64_t> &Record,
2015                                             unsigned Abbrev) {
2016   Record.reserve(N->getElements().size() + 1);
2017   const uint64_t Version = 3 << 1;
2018   Record.push_back((uint64_t)N->isDistinct() | Version);
2019   Record.append(N->elements_begin(), N->elements_end());
2020 
2021   Stream.EmitRecord(bitc::METADATA_EXPRESSION, Record, Abbrev);
2022   Record.clear();
2023 }
2024 
2025 void ModuleBitcodeWriter::writeDIGlobalVariableExpression(
2026     const DIGlobalVariableExpression *N, SmallVectorImpl<uint64_t> &Record,
2027     unsigned Abbrev) {
2028   Record.push_back(N->isDistinct());
2029   Record.push_back(VE.getMetadataOrNullID(N->getVariable()));
2030   Record.push_back(VE.getMetadataOrNullID(N->getExpression()));
2031 
2032   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR_EXPR, Record, Abbrev);
2033   Record.clear();
2034 }
2035 
2036 void ModuleBitcodeWriter::writeDIObjCProperty(const DIObjCProperty *N,
2037                                               SmallVectorImpl<uint64_t> &Record,
2038                                               unsigned Abbrev) {
2039   Record.push_back(N->isDistinct());
2040   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2041   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
2042   Record.push_back(N->getLine());
2043   Record.push_back(VE.getMetadataOrNullID(N->getRawSetterName()));
2044   Record.push_back(VE.getMetadataOrNullID(N->getRawGetterName()));
2045   Record.push_back(N->getAttributes());
2046   Record.push_back(VE.getMetadataOrNullID(N->getType()));
2047 
2048   Stream.EmitRecord(bitc::METADATA_OBJC_PROPERTY, Record, Abbrev);
2049   Record.clear();
2050 }
2051 
2052 void ModuleBitcodeWriter::writeDIImportedEntity(
2053     const DIImportedEntity *N, SmallVectorImpl<uint64_t> &Record,
2054     unsigned Abbrev) {
2055   Record.push_back(N->isDistinct());
2056   Record.push_back(N->getTag());
2057   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
2058   Record.push_back(VE.getMetadataOrNullID(N->getEntity()));
2059   Record.push_back(N->getLine());
2060   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
2061   Record.push_back(VE.getMetadataOrNullID(N->getRawFile()));
2062 
2063   Stream.EmitRecord(bitc::METADATA_IMPORTED_ENTITY, Record, Abbrev);
2064   Record.clear();
2065 }
2066 
2067 unsigned ModuleBitcodeWriter::createNamedMetadataAbbrev() {
2068   auto Abbv = std::make_shared<BitCodeAbbrev>();
2069   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
2070   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2071   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2072   return Stream.EmitAbbrev(std::move(Abbv));
2073 }
2074 
2075 void ModuleBitcodeWriter::writeNamedMetadata(
2076     SmallVectorImpl<uint64_t> &Record) {
2077   if (M.named_metadata_empty())
2078     return;
2079 
2080   unsigned Abbrev = createNamedMetadataAbbrev();
2081   for (const NamedMDNode &NMD : M.named_metadata()) {
2082     // Write name.
2083     StringRef Str = NMD.getName();
2084     Record.append(Str.bytes_begin(), Str.bytes_end());
2085     Stream.EmitRecord(bitc::METADATA_NAME, Record, Abbrev);
2086     Record.clear();
2087 
2088     // Write named metadata operands.
2089     for (const MDNode *N : NMD.operands())
2090       Record.push_back(VE.getMetadataID(N));
2091     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
2092     Record.clear();
2093   }
2094 }
2095 
2096 unsigned ModuleBitcodeWriter::createMetadataStringsAbbrev() {
2097   auto Abbv = std::make_shared<BitCodeAbbrev>();
2098   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRINGS));
2099   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // # of strings
2100   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // offset to chars
2101   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
2102   return Stream.EmitAbbrev(std::move(Abbv));
2103 }
2104 
2105 /// Write out a record for MDString.
2106 ///
2107 /// All the metadata strings in a metadata block are emitted in a single
2108 /// record.  The sizes and strings themselves are shoved into a blob.
2109 void ModuleBitcodeWriter::writeMetadataStrings(
2110     ArrayRef<const Metadata *> Strings, SmallVectorImpl<uint64_t> &Record) {
2111   if (Strings.empty())
2112     return;
2113 
2114   // Start the record with the number of strings.
2115   Record.push_back(bitc::METADATA_STRINGS);
2116   Record.push_back(Strings.size());
2117 
2118   // Emit the sizes of the strings in the blob.
2119   SmallString<256> Blob;
2120   {
2121     BitstreamWriter W(Blob);
2122     for (const Metadata *MD : Strings)
2123       W.EmitVBR(cast<MDString>(MD)->getLength(), 6);
2124     W.FlushToWord();
2125   }
2126 
2127   // Add the offset to the strings to the record.
2128   Record.push_back(Blob.size());
2129 
2130   // Add the strings to the blob.
2131   for (const Metadata *MD : Strings)
2132     Blob.append(cast<MDString>(MD)->getString());
2133 
2134   // Emit the final record.
2135   Stream.EmitRecordWithBlob(createMetadataStringsAbbrev(), Record, Blob);
2136   Record.clear();
2137 }
2138 
2139 // Generates an enum to use as an index in the Abbrev array of Metadata record.
2140 enum MetadataAbbrev : unsigned {
2141 #define HANDLE_MDNODE_LEAF(CLASS) CLASS##AbbrevID,
2142 #include "llvm/IR/Metadata.def"
2143   LastPlusOne
2144 };
2145 
2146 void ModuleBitcodeWriter::writeMetadataRecords(
2147     ArrayRef<const Metadata *> MDs, SmallVectorImpl<uint64_t> &Record,
2148     std::vector<unsigned> *MDAbbrevs, std::vector<uint64_t> *IndexPos) {
2149   if (MDs.empty())
2150     return;
2151 
2152   // Initialize MDNode abbreviations.
2153 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
2154 #include "llvm/IR/Metadata.def"
2155 
2156   for (const Metadata *MD : MDs) {
2157     if (IndexPos)
2158       IndexPos->push_back(Stream.GetCurrentBitNo());
2159     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
2160       assert(N->isResolved() && "Expected forward references to be resolved");
2161 
2162       switch (N->getMetadataID()) {
2163       default:
2164         llvm_unreachable("Invalid MDNode subclass");
2165 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
2166   case Metadata::CLASS##Kind:                                                  \
2167     if (MDAbbrevs)                                                             \
2168       write##CLASS(cast<CLASS>(N), Record,                                     \
2169                    (*MDAbbrevs)[MetadataAbbrev::CLASS##AbbrevID]);             \
2170     else                                                                       \
2171       write##CLASS(cast<CLASS>(N), Record, CLASS##Abbrev);                     \
2172     continue;
2173 #include "llvm/IR/Metadata.def"
2174       }
2175     }
2176     writeValueAsMetadata(cast<ValueAsMetadata>(MD), Record);
2177   }
2178 }
2179 
2180 void ModuleBitcodeWriter::writeModuleMetadata() {
2181   if (!VE.hasMDs() && M.named_metadata_empty())
2182     return;
2183 
2184   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 4);
2185   SmallVector<uint64_t, 64> Record;
2186 
2187   // Emit all abbrevs upfront, so that the reader can jump in the middle of the
2188   // block and load any metadata.
2189   std::vector<unsigned> MDAbbrevs;
2190 
2191   MDAbbrevs.resize(MetadataAbbrev::LastPlusOne);
2192   MDAbbrevs[MetadataAbbrev::DILocationAbbrevID] = createDILocationAbbrev();
2193   MDAbbrevs[MetadataAbbrev::GenericDINodeAbbrevID] =
2194       createGenericDINodeAbbrev();
2195 
2196   auto Abbv = std::make_shared<BitCodeAbbrev>();
2197   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX_OFFSET));
2198   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2199   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2200   unsigned OffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2201 
2202   Abbv = std::make_shared<BitCodeAbbrev>();
2203   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX));
2204   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2205   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2206   unsigned IndexAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2207 
2208   // Emit MDStrings together upfront.
2209   writeMetadataStrings(VE.getMDStrings(), Record);
2210 
2211   // We only emit an index for the metadata record if we have more than a given
2212   // (naive) threshold of metadatas, otherwise it is not worth it.
2213   if (VE.getNonMDStrings().size() > IndexThreshold) {
2214     // Write a placeholder value in for the offset of the metadata index,
2215     // which is written after the records, so that it can include
2216     // the offset of each entry. The placeholder offset will be
2217     // updated after all records are emitted.
2218     uint64_t Vals[] = {0, 0};
2219     Stream.EmitRecord(bitc::METADATA_INDEX_OFFSET, Vals, OffsetAbbrev);
2220   }
2221 
2222   // Compute and save the bit offset to the current position, which will be
2223   // patched when we emit the index later. We can simply subtract the 64-bit
2224   // fixed size from the current bit number to get the location to backpatch.
2225   uint64_t IndexOffsetRecordBitPos = Stream.GetCurrentBitNo();
2226 
2227   // This index will contain the bitpos for each individual record.
2228   std::vector<uint64_t> IndexPos;
2229   IndexPos.reserve(VE.getNonMDStrings().size());
2230 
2231   // Write all the records
2232   writeMetadataRecords(VE.getNonMDStrings(), Record, &MDAbbrevs, &IndexPos);
2233 
2234   if (VE.getNonMDStrings().size() > IndexThreshold) {
2235     // Now that we have emitted all the records we will emit the index. But
2236     // first
2237     // backpatch the forward reference so that the reader can skip the records
2238     // efficiently.
2239     Stream.BackpatchWord64(IndexOffsetRecordBitPos - 64,
2240                            Stream.GetCurrentBitNo() - IndexOffsetRecordBitPos);
2241 
2242     // Delta encode the index.
2243     uint64_t PreviousValue = IndexOffsetRecordBitPos;
2244     for (auto &Elt : IndexPos) {
2245       auto EltDelta = Elt - PreviousValue;
2246       PreviousValue = Elt;
2247       Elt = EltDelta;
2248     }
2249     // Emit the index record.
2250     Stream.EmitRecord(bitc::METADATA_INDEX, IndexPos, IndexAbbrev);
2251     IndexPos.clear();
2252   }
2253 
2254   // Write the named metadata now.
2255   writeNamedMetadata(Record);
2256 
2257   auto AddDeclAttachedMetadata = [&](const GlobalObject &GO) {
2258     SmallVector<uint64_t, 4> Record;
2259     Record.push_back(VE.getValueID(&GO));
2260     pushGlobalMetadataAttachment(Record, GO);
2261     Stream.EmitRecord(bitc::METADATA_GLOBAL_DECL_ATTACHMENT, Record);
2262   };
2263   for (const Function &F : M)
2264     if (F.isDeclaration() && F.hasMetadata())
2265       AddDeclAttachedMetadata(F);
2266   // FIXME: Only store metadata for declarations here, and move data for global
2267   // variable definitions to a separate block (PR28134).
2268   for (const GlobalVariable &GV : M.globals())
2269     if (GV.hasMetadata())
2270       AddDeclAttachedMetadata(GV);
2271 
2272   Stream.ExitBlock();
2273 }
2274 
2275 void ModuleBitcodeWriter::writeFunctionMetadata(const Function &F) {
2276   if (!VE.hasMDs())
2277     return;
2278 
2279   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
2280   SmallVector<uint64_t, 64> Record;
2281   writeMetadataStrings(VE.getMDStrings(), Record);
2282   writeMetadataRecords(VE.getNonMDStrings(), Record);
2283   Stream.ExitBlock();
2284 }
2285 
2286 void ModuleBitcodeWriter::pushGlobalMetadataAttachment(
2287     SmallVectorImpl<uint64_t> &Record, const GlobalObject &GO) {
2288   // [n x [id, mdnode]]
2289   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2290   GO.getAllMetadata(MDs);
2291   for (const auto &I : MDs) {
2292     Record.push_back(I.first);
2293     Record.push_back(VE.getMetadataID(I.second));
2294   }
2295 }
2296 
2297 void ModuleBitcodeWriter::writeFunctionMetadataAttachment(const Function &F) {
2298   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
2299 
2300   SmallVector<uint64_t, 64> Record;
2301 
2302   if (F.hasMetadata()) {
2303     pushGlobalMetadataAttachment(Record, F);
2304     Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2305     Record.clear();
2306   }
2307 
2308   // Write metadata attachments
2309   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
2310   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2311   for (const BasicBlock &BB : F)
2312     for (const Instruction &I : BB) {
2313       MDs.clear();
2314       I.getAllMetadataOtherThanDebugLoc(MDs);
2315 
2316       // If no metadata, ignore instruction.
2317       if (MDs.empty()) continue;
2318 
2319       Record.push_back(VE.getInstructionID(&I));
2320 
2321       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
2322         Record.push_back(MDs[i].first);
2323         Record.push_back(VE.getMetadataID(MDs[i].second));
2324       }
2325       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2326       Record.clear();
2327     }
2328 
2329   Stream.ExitBlock();
2330 }
2331 
2332 void ModuleBitcodeWriter::writeModuleMetadataKinds() {
2333   SmallVector<uint64_t, 64> Record;
2334 
2335   // Write metadata kinds
2336   // METADATA_KIND - [n x [id, name]]
2337   SmallVector<StringRef, 8> Names;
2338   M.getMDKindNames(Names);
2339 
2340   if (Names.empty()) return;
2341 
2342   Stream.EnterSubblock(bitc::METADATA_KIND_BLOCK_ID, 3);
2343 
2344   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
2345     Record.push_back(MDKindID);
2346     StringRef KName = Names[MDKindID];
2347     Record.append(KName.begin(), KName.end());
2348 
2349     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
2350     Record.clear();
2351   }
2352 
2353   Stream.ExitBlock();
2354 }
2355 
2356 void ModuleBitcodeWriter::writeOperandBundleTags() {
2357   // Write metadata kinds
2358   //
2359   // OPERAND_BUNDLE_TAGS_BLOCK_ID : N x OPERAND_BUNDLE_TAG
2360   //
2361   // OPERAND_BUNDLE_TAG - [strchr x N]
2362 
2363   SmallVector<StringRef, 8> Tags;
2364   M.getOperandBundleTags(Tags);
2365 
2366   if (Tags.empty())
2367     return;
2368 
2369   Stream.EnterSubblock(bitc::OPERAND_BUNDLE_TAGS_BLOCK_ID, 3);
2370 
2371   SmallVector<uint64_t, 64> Record;
2372 
2373   for (auto Tag : Tags) {
2374     Record.append(Tag.begin(), Tag.end());
2375 
2376     Stream.EmitRecord(bitc::OPERAND_BUNDLE_TAG, Record, 0);
2377     Record.clear();
2378   }
2379 
2380   Stream.ExitBlock();
2381 }
2382 
2383 void ModuleBitcodeWriter::writeSyncScopeNames() {
2384   SmallVector<StringRef, 8> SSNs;
2385   M.getContext().getSyncScopeNames(SSNs);
2386   if (SSNs.empty())
2387     return;
2388 
2389   Stream.EnterSubblock(bitc::SYNC_SCOPE_NAMES_BLOCK_ID, 2);
2390 
2391   SmallVector<uint64_t, 64> Record;
2392   for (auto SSN : SSNs) {
2393     Record.append(SSN.begin(), SSN.end());
2394     Stream.EmitRecord(bitc::SYNC_SCOPE_NAME, Record, 0);
2395     Record.clear();
2396   }
2397 
2398   Stream.ExitBlock();
2399 }
2400 
2401 void ModuleBitcodeWriter::writeConstants(unsigned FirstVal, unsigned LastVal,
2402                                          bool isGlobal) {
2403   if (FirstVal == LastVal) return;
2404 
2405   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
2406 
2407   unsigned AggregateAbbrev = 0;
2408   unsigned String8Abbrev = 0;
2409   unsigned CString7Abbrev = 0;
2410   unsigned CString6Abbrev = 0;
2411   // If this is a constant pool for the module, emit module-specific abbrevs.
2412   if (isGlobal) {
2413     // Abbrev for CST_CODE_AGGREGATE.
2414     auto Abbv = std::make_shared<BitCodeAbbrev>();
2415     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
2416     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2417     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
2418     AggregateAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2419 
2420     // Abbrev for CST_CODE_STRING.
2421     Abbv = std::make_shared<BitCodeAbbrev>();
2422     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
2423     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2424     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2425     String8Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2426     // Abbrev for CST_CODE_CSTRING.
2427     Abbv = std::make_shared<BitCodeAbbrev>();
2428     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2429     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2430     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2431     CString7Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2432     // Abbrev for CST_CODE_CSTRING.
2433     Abbv = std::make_shared<BitCodeAbbrev>();
2434     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2435     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2436     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2437     CString6Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2438   }
2439 
2440   SmallVector<uint64_t, 64> Record;
2441 
2442   const ValueEnumerator::ValueList &Vals = VE.getValues();
2443   Type *LastTy = nullptr;
2444   for (unsigned i = FirstVal; i != LastVal; ++i) {
2445     const Value *V = Vals[i].first;
2446     // If we need to switch types, do so now.
2447     if (V->getType() != LastTy) {
2448       LastTy = V->getType();
2449       Record.push_back(VE.getTypeID(LastTy));
2450       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
2451                         CONSTANTS_SETTYPE_ABBREV);
2452       Record.clear();
2453     }
2454 
2455     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
2456       Record.push_back(
2457           unsigned(IA->hasSideEffects()) | unsigned(IA->isAlignStack()) << 1 |
2458           unsigned(IA->getDialect() & 1) << 2 | unsigned(IA->canThrow()) << 3);
2459 
2460       // Add the asm string.
2461       const std::string &AsmStr = IA->getAsmString();
2462       Record.push_back(AsmStr.size());
2463       Record.append(AsmStr.begin(), AsmStr.end());
2464 
2465       // Add the constraint string.
2466       const std::string &ConstraintStr = IA->getConstraintString();
2467       Record.push_back(ConstraintStr.size());
2468       Record.append(ConstraintStr.begin(), ConstraintStr.end());
2469       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
2470       Record.clear();
2471       continue;
2472     }
2473     const Constant *C = cast<Constant>(V);
2474     unsigned Code = -1U;
2475     unsigned AbbrevToUse = 0;
2476     if (C->isNullValue()) {
2477       Code = bitc::CST_CODE_NULL;
2478     } else if (isa<PoisonValue>(C)) {
2479       Code = bitc::CST_CODE_POISON;
2480     } else if (isa<UndefValue>(C)) {
2481       Code = bitc::CST_CODE_UNDEF;
2482     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
2483       if (IV->getBitWidth() <= 64) {
2484         uint64_t V = IV->getSExtValue();
2485         emitSignedInt64(Record, V);
2486         Code = bitc::CST_CODE_INTEGER;
2487         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
2488       } else {                             // Wide integers, > 64 bits in size.
2489         emitWideAPInt(Record, IV->getValue());
2490         Code = bitc::CST_CODE_WIDE_INTEGER;
2491       }
2492     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
2493       Code = bitc::CST_CODE_FLOAT;
2494       Type *Ty = CFP->getType();
2495       if (Ty->isHalfTy() || Ty->isBFloatTy() || Ty->isFloatTy() ||
2496           Ty->isDoubleTy()) {
2497         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
2498       } else if (Ty->isX86_FP80Ty()) {
2499         // api needed to prevent premature destruction
2500         // bits are not in the same order as a normal i80 APInt, compensate.
2501         APInt api = CFP->getValueAPF().bitcastToAPInt();
2502         const uint64_t *p = api.getRawData();
2503         Record.push_back((p[1] << 48) | (p[0] >> 16));
2504         Record.push_back(p[0] & 0xffffLL);
2505       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
2506         APInt api = CFP->getValueAPF().bitcastToAPInt();
2507         const uint64_t *p = api.getRawData();
2508         Record.push_back(p[0]);
2509         Record.push_back(p[1]);
2510       } else {
2511         assert(0 && "Unknown FP type!");
2512       }
2513     } else if (isa<ConstantDataSequential>(C) &&
2514                cast<ConstantDataSequential>(C)->isString()) {
2515       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
2516       // Emit constant strings specially.
2517       unsigned NumElts = Str->getNumElements();
2518       // If this is a null-terminated string, use the denser CSTRING encoding.
2519       if (Str->isCString()) {
2520         Code = bitc::CST_CODE_CSTRING;
2521         --NumElts;  // Don't encode the null, which isn't allowed by char6.
2522       } else {
2523         Code = bitc::CST_CODE_STRING;
2524         AbbrevToUse = String8Abbrev;
2525       }
2526       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
2527       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
2528       for (unsigned i = 0; i != NumElts; ++i) {
2529         unsigned char V = Str->getElementAsInteger(i);
2530         Record.push_back(V);
2531         isCStr7 &= (V & 128) == 0;
2532         if (isCStrChar6)
2533           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
2534       }
2535 
2536       if (isCStrChar6)
2537         AbbrevToUse = CString6Abbrev;
2538       else if (isCStr7)
2539         AbbrevToUse = CString7Abbrev;
2540     } else if (const ConstantDataSequential *CDS =
2541                   dyn_cast<ConstantDataSequential>(C)) {
2542       Code = bitc::CST_CODE_DATA;
2543       Type *EltTy = CDS->getElementType();
2544       if (isa<IntegerType>(EltTy)) {
2545         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2546           Record.push_back(CDS->getElementAsInteger(i));
2547       } else {
2548         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2549           Record.push_back(
2550               CDS->getElementAsAPFloat(i).bitcastToAPInt().getLimitedValue());
2551       }
2552     } else if (isa<ConstantAggregate>(C)) {
2553       Code = bitc::CST_CODE_AGGREGATE;
2554       for (const Value *Op : C->operands())
2555         Record.push_back(VE.getValueID(Op));
2556       AbbrevToUse = AggregateAbbrev;
2557     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
2558       switch (CE->getOpcode()) {
2559       default:
2560         if (Instruction::isCast(CE->getOpcode())) {
2561           Code = bitc::CST_CODE_CE_CAST;
2562           Record.push_back(getEncodedCastOpcode(CE->getOpcode()));
2563           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2564           Record.push_back(VE.getValueID(C->getOperand(0)));
2565           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
2566         } else {
2567           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
2568           Code = bitc::CST_CODE_CE_BINOP;
2569           Record.push_back(getEncodedBinaryOpcode(CE->getOpcode()));
2570           Record.push_back(VE.getValueID(C->getOperand(0)));
2571           Record.push_back(VE.getValueID(C->getOperand(1)));
2572           uint64_t Flags = getOptimizationFlags(CE);
2573           if (Flags != 0)
2574             Record.push_back(Flags);
2575         }
2576         break;
2577       case Instruction::FNeg: {
2578         assert(CE->getNumOperands() == 1 && "Unknown constant expr!");
2579         Code = bitc::CST_CODE_CE_UNOP;
2580         Record.push_back(getEncodedUnaryOpcode(CE->getOpcode()));
2581         Record.push_back(VE.getValueID(C->getOperand(0)));
2582         uint64_t Flags = getOptimizationFlags(CE);
2583         if (Flags != 0)
2584           Record.push_back(Flags);
2585         break;
2586       }
2587       case Instruction::GetElementPtr: {
2588         Code = bitc::CST_CODE_CE_GEP;
2589         const auto *GO = cast<GEPOperator>(C);
2590         Record.push_back(VE.getTypeID(GO->getSourceElementType()));
2591         if (Optional<unsigned> Idx = GO->getInRangeIndex()) {
2592           Code = bitc::CST_CODE_CE_GEP_WITH_INRANGE_INDEX;
2593           Record.push_back((*Idx << 1) | GO->isInBounds());
2594         } else if (GO->isInBounds())
2595           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
2596         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
2597           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
2598           Record.push_back(VE.getValueID(C->getOperand(i)));
2599         }
2600         break;
2601       }
2602       case Instruction::Select:
2603         Code = bitc::CST_CODE_CE_SELECT;
2604         Record.push_back(VE.getValueID(C->getOperand(0)));
2605         Record.push_back(VE.getValueID(C->getOperand(1)));
2606         Record.push_back(VE.getValueID(C->getOperand(2)));
2607         break;
2608       case Instruction::ExtractElement:
2609         Code = bitc::CST_CODE_CE_EXTRACTELT;
2610         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2611         Record.push_back(VE.getValueID(C->getOperand(0)));
2612         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
2613         Record.push_back(VE.getValueID(C->getOperand(1)));
2614         break;
2615       case Instruction::InsertElement:
2616         Code = bitc::CST_CODE_CE_INSERTELT;
2617         Record.push_back(VE.getValueID(C->getOperand(0)));
2618         Record.push_back(VE.getValueID(C->getOperand(1)));
2619         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
2620         Record.push_back(VE.getValueID(C->getOperand(2)));
2621         break;
2622       case Instruction::ShuffleVector:
2623         // If the return type and argument types are the same, this is a
2624         // standard shufflevector instruction.  If the types are different,
2625         // then the shuffle is widening or truncating the input vectors, and
2626         // the argument type must also be encoded.
2627         if (C->getType() == C->getOperand(0)->getType()) {
2628           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
2629         } else {
2630           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
2631           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2632         }
2633         Record.push_back(VE.getValueID(C->getOperand(0)));
2634         Record.push_back(VE.getValueID(C->getOperand(1)));
2635         Record.push_back(VE.getValueID(CE->getShuffleMaskForBitcode()));
2636         break;
2637       case Instruction::ICmp:
2638       case Instruction::FCmp:
2639         Code = bitc::CST_CODE_CE_CMP;
2640         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2641         Record.push_back(VE.getValueID(C->getOperand(0)));
2642         Record.push_back(VE.getValueID(C->getOperand(1)));
2643         Record.push_back(CE->getPredicate());
2644         break;
2645       }
2646     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
2647       Code = bitc::CST_CODE_BLOCKADDRESS;
2648       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
2649       Record.push_back(VE.getValueID(BA->getFunction()));
2650       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
2651     } else if (const auto *Equiv = dyn_cast<DSOLocalEquivalent>(C)) {
2652       Code = bitc::CST_CODE_DSO_LOCAL_EQUIVALENT;
2653       Record.push_back(VE.getTypeID(Equiv->getGlobalValue()->getType()));
2654       Record.push_back(VE.getValueID(Equiv->getGlobalValue()));
2655     } else {
2656 #ifndef NDEBUG
2657       C->dump();
2658 #endif
2659       llvm_unreachable("Unknown constant!");
2660     }
2661     Stream.EmitRecord(Code, Record, AbbrevToUse);
2662     Record.clear();
2663   }
2664 
2665   Stream.ExitBlock();
2666 }
2667 
2668 void ModuleBitcodeWriter::writeModuleConstants() {
2669   const ValueEnumerator::ValueList &Vals = VE.getValues();
2670 
2671   // Find the first constant to emit, which is the first non-globalvalue value.
2672   // We know globalvalues have been emitted by WriteModuleInfo.
2673   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
2674     if (!isa<GlobalValue>(Vals[i].first)) {
2675       writeConstants(i, Vals.size(), true);
2676       return;
2677     }
2678   }
2679 }
2680 
2681 /// pushValueAndType - The file has to encode both the value and type id for
2682 /// many values, because we need to know what type to create for forward
2683 /// references.  However, most operands are not forward references, so this type
2684 /// field is not needed.
2685 ///
2686 /// This function adds V's value ID to Vals.  If the value ID is higher than the
2687 /// instruction ID, then it is a forward reference, and it also includes the
2688 /// type ID.  The value ID that is written is encoded relative to the InstID.
2689 bool ModuleBitcodeWriter::pushValueAndType(const Value *V, unsigned InstID,
2690                                            SmallVectorImpl<unsigned> &Vals) {
2691   unsigned ValID = VE.getValueID(V);
2692   // Make encoding relative to the InstID.
2693   Vals.push_back(InstID - ValID);
2694   if (ValID >= InstID) {
2695     Vals.push_back(VE.getTypeID(V->getType()));
2696     return true;
2697   }
2698   return false;
2699 }
2700 
2701 void ModuleBitcodeWriter::writeOperandBundles(const CallBase &CS,
2702                                               unsigned InstID) {
2703   SmallVector<unsigned, 64> Record;
2704   LLVMContext &C = CS.getContext();
2705 
2706   for (unsigned i = 0, e = CS.getNumOperandBundles(); i != e; ++i) {
2707     const auto &Bundle = CS.getOperandBundleAt(i);
2708     Record.push_back(C.getOperandBundleTagID(Bundle.getTagName()));
2709 
2710     for (auto &Input : Bundle.Inputs)
2711       pushValueAndType(Input, InstID, Record);
2712 
2713     Stream.EmitRecord(bitc::FUNC_CODE_OPERAND_BUNDLE, Record);
2714     Record.clear();
2715   }
2716 }
2717 
2718 /// pushValue - Like pushValueAndType, but where the type of the value is
2719 /// omitted (perhaps it was already encoded in an earlier operand).
2720 void ModuleBitcodeWriter::pushValue(const Value *V, unsigned InstID,
2721                                     SmallVectorImpl<unsigned> &Vals) {
2722   unsigned ValID = VE.getValueID(V);
2723   Vals.push_back(InstID - ValID);
2724 }
2725 
2726 void ModuleBitcodeWriter::pushValueSigned(const Value *V, unsigned InstID,
2727                                           SmallVectorImpl<uint64_t> &Vals) {
2728   unsigned ValID = VE.getValueID(V);
2729   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
2730   emitSignedInt64(Vals, diff);
2731 }
2732 
2733 /// WriteInstruction - Emit an instruction to the specified stream.
2734 void ModuleBitcodeWriter::writeInstruction(const Instruction &I,
2735                                            unsigned InstID,
2736                                            SmallVectorImpl<unsigned> &Vals) {
2737   unsigned Code = 0;
2738   unsigned AbbrevToUse = 0;
2739   VE.setInstructionID(&I);
2740   switch (I.getOpcode()) {
2741   default:
2742     if (Instruction::isCast(I.getOpcode())) {
2743       Code = bitc::FUNC_CODE_INST_CAST;
2744       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2745         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
2746       Vals.push_back(VE.getTypeID(I.getType()));
2747       Vals.push_back(getEncodedCastOpcode(I.getOpcode()));
2748     } else {
2749       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
2750       Code = bitc::FUNC_CODE_INST_BINOP;
2751       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2752         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
2753       pushValue(I.getOperand(1), InstID, Vals);
2754       Vals.push_back(getEncodedBinaryOpcode(I.getOpcode()));
2755       uint64_t Flags = getOptimizationFlags(&I);
2756       if (Flags != 0) {
2757         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
2758           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
2759         Vals.push_back(Flags);
2760       }
2761     }
2762     break;
2763   case Instruction::FNeg: {
2764     Code = bitc::FUNC_CODE_INST_UNOP;
2765     if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2766       AbbrevToUse = FUNCTION_INST_UNOP_ABBREV;
2767     Vals.push_back(getEncodedUnaryOpcode(I.getOpcode()));
2768     uint64_t Flags = getOptimizationFlags(&I);
2769     if (Flags != 0) {
2770       if (AbbrevToUse == FUNCTION_INST_UNOP_ABBREV)
2771         AbbrevToUse = FUNCTION_INST_UNOP_FLAGS_ABBREV;
2772       Vals.push_back(Flags);
2773     }
2774     break;
2775   }
2776   case Instruction::GetElementPtr: {
2777     Code = bitc::FUNC_CODE_INST_GEP;
2778     AbbrevToUse = FUNCTION_INST_GEP_ABBREV;
2779     auto &GEPInst = cast<GetElementPtrInst>(I);
2780     Vals.push_back(GEPInst.isInBounds());
2781     Vals.push_back(VE.getTypeID(GEPInst.getSourceElementType()));
2782     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
2783       pushValueAndType(I.getOperand(i), InstID, Vals);
2784     break;
2785   }
2786   case Instruction::ExtractValue: {
2787     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
2788     pushValueAndType(I.getOperand(0), InstID, Vals);
2789     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
2790     Vals.append(EVI->idx_begin(), EVI->idx_end());
2791     break;
2792   }
2793   case Instruction::InsertValue: {
2794     Code = bitc::FUNC_CODE_INST_INSERTVAL;
2795     pushValueAndType(I.getOperand(0), InstID, Vals);
2796     pushValueAndType(I.getOperand(1), InstID, Vals);
2797     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
2798     Vals.append(IVI->idx_begin(), IVI->idx_end());
2799     break;
2800   }
2801   case Instruction::Select: {
2802     Code = bitc::FUNC_CODE_INST_VSELECT;
2803     pushValueAndType(I.getOperand(1), InstID, Vals);
2804     pushValue(I.getOperand(2), InstID, Vals);
2805     pushValueAndType(I.getOperand(0), InstID, Vals);
2806     uint64_t Flags = getOptimizationFlags(&I);
2807     if (Flags != 0)
2808       Vals.push_back(Flags);
2809     break;
2810   }
2811   case Instruction::ExtractElement:
2812     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
2813     pushValueAndType(I.getOperand(0), InstID, Vals);
2814     pushValueAndType(I.getOperand(1), InstID, Vals);
2815     break;
2816   case Instruction::InsertElement:
2817     Code = bitc::FUNC_CODE_INST_INSERTELT;
2818     pushValueAndType(I.getOperand(0), InstID, Vals);
2819     pushValue(I.getOperand(1), InstID, Vals);
2820     pushValueAndType(I.getOperand(2), InstID, Vals);
2821     break;
2822   case Instruction::ShuffleVector:
2823     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
2824     pushValueAndType(I.getOperand(0), InstID, Vals);
2825     pushValue(I.getOperand(1), InstID, Vals);
2826     pushValue(cast<ShuffleVectorInst>(I).getShuffleMaskForBitcode(), InstID,
2827               Vals);
2828     break;
2829   case Instruction::ICmp:
2830   case Instruction::FCmp: {
2831     // compare returning Int1Ty or vector of Int1Ty
2832     Code = bitc::FUNC_CODE_INST_CMP2;
2833     pushValueAndType(I.getOperand(0), InstID, Vals);
2834     pushValue(I.getOperand(1), InstID, Vals);
2835     Vals.push_back(cast<CmpInst>(I).getPredicate());
2836     uint64_t Flags = getOptimizationFlags(&I);
2837     if (Flags != 0)
2838       Vals.push_back(Flags);
2839     break;
2840   }
2841 
2842   case Instruction::Ret:
2843     {
2844       Code = bitc::FUNC_CODE_INST_RET;
2845       unsigned NumOperands = I.getNumOperands();
2846       if (NumOperands == 0)
2847         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
2848       else if (NumOperands == 1) {
2849         if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2850           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
2851       } else {
2852         for (unsigned i = 0, e = NumOperands; i != e; ++i)
2853           pushValueAndType(I.getOperand(i), InstID, Vals);
2854       }
2855     }
2856     break;
2857   case Instruction::Br:
2858     {
2859       Code = bitc::FUNC_CODE_INST_BR;
2860       const BranchInst &II = cast<BranchInst>(I);
2861       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
2862       if (II.isConditional()) {
2863         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
2864         pushValue(II.getCondition(), InstID, Vals);
2865       }
2866     }
2867     break;
2868   case Instruction::Switch:
2869     {
2870       Code = bitc::FUNC_CODE_INST_SWITCH;
2871       const SwitchInst &SI = cast<SwitchInst>(I);
2872       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
2873       pushValue(SI.getCondition(), InstID, Vals);
2874       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
2875       for (auto Case : SI.cases()) {
2876         Vals.push_back(VE.getValueID(Case.getCaseValue()));
2877         Vals.push_back(VE.getValueID(Case.getCaseSuccessor()));
2878       }
2879     }
2880     break;
2881   case Instruction::IndirectBr:
2882     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
2883     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2884     // Encode the address operand as relative, but not the basic blocks.
2885     pushValue(I.getOperand(0), InstID, Vals);
2886     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
2887       Vals.push_back(VE.getValueID(I.getOperand(i)));
2888     break;
2889 
2890   case Instruction::Invoke: {
2891     const InvokeInst *II = cast<InvokeInst>(&I);
2892     const Value *Callee = II->getCalledOperand();
2893     FunctionType *FTy = II->getFunctionType();
2894 
2895     if (II->hasOperandBundles())
2896       writeOperandBundles(*II, InstID);
2897 
2898     Code = bitc::FUNC_CODE_INST_INVOKE;
2899 
2900     Vals.push_back(VE.getAttributeListID(II->getAttributes()));
2901     Vals.push_back(II->getCallingConv() | 1 << 13);
2902     Vals.push_back(VE.getValueID(II->getNormalDest()));
2903     Vals.push_back(VE.getValueID(II->getUnwindDest()));
2904     Vals.push_back(VE.getTypeID(FTy));
2905     pushValueAndType(Callee, InstID, Vals);
2906 
2907     // Emit value #'s for the fixed parameters.
2908     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
2909       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
2910 
2911     // Emit type/value pairs for varargs params.
2912     if (FTy->isVarArg()) {
2913       for (unsigned i = FTy->getNumParams(), e = II->getNumArgOperands();
2914            i != e; ++i)
2915         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
2916     }
2917     break;
2918   }
2919   case Instruction::Resume:
2920     Code = bitc::FUNC_CODE_INST_RESUME;
2921     pushValueAndType(I.getOperand(0), InstID, Vals);
2922     break;
2923   case Instruction::CleanupRet: {
2924     Code = bitc::FUNC_CODE_INST_CLEANUPRET;
2925     const auto &CRI = cast<CleanupReturnInst>(I);
2926     pushValue(CRI.getCleanupPad(), InstID, Vals);
2927     if (CRI.hasUnwindDest())
2928       Vals.push_back(VE.getValueID(CRI.getUnwindDest()));
2929     break;
2930   }
2931   case Instruction::CatchRet: {
2932     Code = bitc::FUNC_CODE_INST_CATCHRET;
2933     const auto &CRI = cast<CatchReturnInst>(I);
2934     pushValue(CRI.getCatchPad(), InstID, Vals);
2935     Vals.push_back(VE.getValueID(CRI.getSuccessor()));
2936     break;
2937   }
2938   case Instruction::CleanupPad:
2939   case Instruction::CatchPad: {
2940     const auto &FuncletPad = cast<FuncletPadInst>(I);
2941     Code = isa<CatchPadInst>(FuncletPad) ? bitc::FUNC_CODE_INST_CATCHPAD
2942                                          : bitc::FUNC_CODE_INST_CLEANUPPAD;
2943     pushValue(FuncletPad.getParentPad(), InstID, Vals);
2944 
2945     unsigned NumArgOperands = FuncletPad.getNumArgOperands();
2946     Vals.push_back(NumArgOperands);
2947     for (unsigned Op = 0; Op != NumArgOperands; ++Op)
2948       pushValueAndType(FuncletPad.getArgOperand(Op), InstID, Vals);
2949     break;
2950   }
2951   case Instruction::CatchSwitch: {
2952     Code = bitc::FUNC_CODE_INST_CATCHSWITCH;
2953     const auto &CatchSwitch = cast<CatchSwitchInst>(I);
2954 
2955     pushValue(CatchSwitch.getParentPad(), InstID, Vals);
2956 
2957     unsigned NumHandlers = CatchSwitch.getNumHandlers();
2958     Vals.push_back(NumHandlers);
2959     for (const BasicBlock *CatchPadBB : CatchSwitch.handlers())
2960       Vals.push_back(VE.getValueID(CatchPadBB));
2961 
2962     if (CatchSwitch.hasUnwindDest())
2963       Vals.push_back(VE.getValueID(CatchSwitch.getUnwindDest()));
2964     break;
2965   }
2966   case Instruction::CallBr: {
2967     const CallBrInst *CBI = cast<CallBrInst>(&I);
2968     const Value *Callee = CBI->getCalledOperand();
2969     FunctionType *FTy = CBI->getFunctionType();
2970 
2971     if (CBI->hasOperandBundles())
2972       writeOperandBundles(*CBI, InstID);
2973 
2974     Code = bitc::FUNC_CODE_INST_CALLBR;
2975 
2976     Vals.push_back(VE.getAttributeListID(CBI->getAttributes()));
2977 
2978     Vals.push_back(CBI->getCallingConv() << bitc::CALL_CCONV |
2979                    1 << bitc::CALL_EXPLICIT_TYPE);
2980 
2981     Vals.push_back(VE.getValueID(CBI->getDefaultDest()));
2982     Vals.push_back(CBI->getNumIndirectDests());
2983     for (unsigned i = 0, e = CBI->getNumIndirectDests(); i != e; ++i)
2984       Vals.push_back(VE.getValueID(CBI->getIndirectDest(i)));
2985 
2986     Vals.push_back(VE.getTypeID(FTy));
2987     pushValueAndType(Callee, InstID, Vals);
2988 
2989     // Emit value #'s for the fixed parameters.
2990     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
2991       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
2992 
2993     // Emit type/value pairs for varargs params.
2994     if (FTy->isVarArg()) {
2995       for (unsigned i = FTy->getNumParams(), e = CBI->getNumArgOperands();
2996            i != e; ++i)
2997         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
2998     }
2999     break;
3000   }
3001   case Instruction::Unreachable:
3002     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
3003     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
3004     break;
3005 
3006   case Instruction::PHI: {
3007     const PHINode &PN = cast<PHINode>(I);
3008     Code = bitc::FUNC_CODE_INST_PHI;
3009     // With the newer instruction encoding, forward references could give
3010     // negative valued IDs.  This is most common for PHIs, so we use
3011     // signed VBRs.
3012     SmallVector<uint64_t, 128> Vals64;
3013     Vals64.push_back(VE.getTypeID(PN.getType()));
3014     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
3015       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64);
3016       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
3017     }
3018 
3019     uint64_t Flags = getOptimizationFlags(&I);
3020     if (Flags != 0)
3021       Vals64.push_back(Flags);
3022 
3023     // Emit a Vals64 vector and exit.
3024     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
3025     Vals64.clear();
3026     return;
3027   }
3028 
3029   case Instruction::LandingPad: {
3030     const LandingPadInst &LP = cast<LandingPadInst>(I);
3031     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
3032     Vals.push_back(VE.getTypeID(LP.getType()));
3033     Vals.push_back(LP.isCleanup());
3034     Vals.push_back(LP.getNumClauses());
3035     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
3036       if (LP.isCatch(I))
3037         Vals.push_back(LandingPadInst::Catch);
3038       else
3039         Vals.push_back(LandingPadInst::Filter);
3040       pushValueAndType(LP.getClause(I), InstID, Vals);
3041     }
3042     break;
3043   }
3044 
3045   case Instruction::Alloca: {
3046     Code = bitc::FUNC_CODE_INST_ALLOCA;
3047     const AllocaInst &AI = cast<AllocaInst>(I);
3048     Vals.push_back(VE.getTypeID(AI.getAllocatedType()));
3049     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
3050     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
3051     using APV = AllocaPackedValues;
3052     unsigned Record = 0;
3053     Bitfield::set<APV::Align>(Record, getEncodedAlign(AI.getAlign()));
3054     Bitfield::set<APV::UsedWithInAlloca>(Record, AI.isUsedWithInAlloca());
3055     Bitfield::set<APV::ExplicitType>(Record, true);
3056     Bitfield::set<APV::SwiftError>(Record, AI.isSwiftError());
3057     Vals.push_back(Record);
3058     break;
3059   }
3060 
3061   case Instruction::Load:
3062     if (cast<LoadInst>(I).isAtomic()) {
3063       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
3064       pushValueAndType(I.getOperand(0), InstID, Vals);
3065     } else {
3066       Code = bitc::FUNC_CODE_INST_LOAD;
3067       if (!pushValueAndType(I.getOperand(0), InstID, Vals)) // ptr
3068         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
3069     }
3070     Vals.push_back(VE.getTypeID(I.getType()));
3071     Vals.push_back(getEncodedAlign(cast<LoadInst>(I).getAlign()));
3072     Vals.push_back(cast<LoadInst>(I).isVolatile());
3073     if (cast<LoadInst>(I).isAtomic()) {
3074       Vals.push_back(getEncodedOrdering(cast<LoadInst>(I).getOrdering()));
3075       Vals.push_back(getEncodedSyncScopeID(cast<LoadInst>(I).getSyncScopeID()));
3076     }
3077     break;
3078   case Instruction::Store:
3079     if (cast<StoreInst>(I).isAtomic())
3080       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
3081     else
3082       Code = bitc::FUNC_CODE_INST_STORE;
3083     pushValueAndType(I.getOperand(1), InstID, Vals); // ptrty + ptr
3084     pushValueAndType(I.getOperand(0), InstID, Vals); // valty + val
3085     Vals.push_back(getEncodedAlign(cast<StoreInst>(I).getAlign()));
3086     Vals.push_back(cast<StoreInst>(I).isVolatile());
3087     if (cast<StoreInst>(I).isAtomic()) {
3088       Vals.push_back(getEncodedOrdering(cast<StoreInst>(I).getOrdering()));
3089       Vals.push_back(
3090           getEncodedSyncScopeID(cast<StoreInst>(I).getSyncScopeID()));
3091     }
3092     break;
3093   case Instruction::AtomicCmpXchg:
3094     Code = bitc::FUNC_CODE_INST_CMPXCHG;
3095     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
3096     pushValueAndType(I.getOperand(1), InstID, Vals); // cmp.
3097     pushValue(I.getOperand(2), InstID, Vals);        // newval.
3098     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
3099     Vals.push_back(
3100         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
3101     Vals.push_back(
3102         getEncodedSyncScopeID(cast<AtomicCmpXchgInst>(I).getSyncScopeID()));
3103     Vals.push_back(
3104         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
3105     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
3106     Vals.push_back(getEncodedAlign(cast<AtomicCmpXchgInst>(I).getAlign()));
3107     break;
3108   case Instruction::AtomicRMW:
3109     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
3110     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
3111     pushValueAndType(I.getOperand(1), InstID, Vals); // valty + val
3112     Vals.push_back(
3113         getEncodedRMWOperation(cast<AtomicRMWInst>(I).getOperation()));
3114     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
3115     Vals.push_back(getEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
3116     Vals.push_back(
3117         getEncodedSyncScopeID(cast<AtomicRMWInst>(I).getSyncScopeID()));
3118     Vals.push_back(getEncodedAlign(cast<AtomicRMWInst>(I).getAlign()));
3119     break;
3120   case Instruction::Fence:
3121     Code = bitc::FUNC_CODE_INST_FENCE;
3122     Vals.push_back(getEncodedOrdering(cast<FenceInst>(I).getOrdering()));
3123     Vals.push_back(getEncodedSyncScopeID(cast<FenceInst>(I).getSyncScopeID()));
3124     break;
3125   case Instruction::Call: {
3126     const CallInst &CI = cast<CallInst>(I);
3127     FunctionType *FTy = CI.getFunctionType();
3128 
3129     if (CI.hasOperandBundles())
3130       writeOperandBundles(CI, InstID);
3131 
3132     Code = bitc::FUNC_CODE_INST_CALL;
3133 
3134     Vals.push_back(VE.getAttributeListID(CI.getAttributes()));
3135 
3136     unsigned Flags = getOptimizationFlags(&I);
3137     Vals.push_back(CI.getCallingConv() << bitc::CALL_CCONV |
3138                    unsigned(CI.isTailCall()) << bitc::CALL_TAIL |
3139                    unsigned(CI.isMustTailCall()) << bitc::CALL_MUSTTAIL |
3140                    1 << bitc::CALL_EXPLICIT_TYPE |
3141                    unsigned(CI.isNoTailCall()) << bitc::CALL_NOTAIL |
3142                    unsigned(Flags != 0) << bitc::CALL_FMF);
3143     if (Flags != 0)
3144       Vals.push_back(Flags);
3145 
3146     Vals.push_back(VE.getTypeID(FTy));
3147     pushValueAndType(CI.getCalledOperand(), InstID, Vals); // Callee
3148 
3149     // Emit value #'s for the fixed parameters.
3150     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
3151       // Check for labels (can happen with asm labels).
3152       if (FTy->getParamType(i)->isLabelTy())
3153         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
3154       else
3155         pushValue(CI.getArgOperand(i), InstID, Vals); // fixed param.
3156     }
3157 
3158     // Emit type/value pairs for varargs params.
3159     if (FTy->isVarArg()) {
3160       for (unsigned i = FTy->getNumParams(), e = CI.getNumArgOperands();
3161            i != e; ++i)
3162         pushValueAndType(CI.getArgOperand(i), InstID, Vals); // varargs
3163     }
3164     break;
3165   }
3166   case Instruction::VAArg:
3167     Code = bitc::FUNC_CODE_INST_VAARG;
3168     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
3169     pushValue(I.getOperand(0), InstID, Vals);                   // valist.
3170     Vals.push_back(VE.getTypeID(I.getType())); // restype.
3171     break;
3172   case Instruction::Freeze:
3173     Code = bitc::FUNC_CODE_INST_FREEZE;
3174     pushValueAndType(I.getOperand(0), InstID, Vals);
3175     break;
3176   }
3177 
3178   Stream.EmitRecord(Code, Vals, AbbrevToUse);
3179   Vals.clear();
3180 }
3181 
3182 /// Write a GlobalValue VST to the module. The purpose of this data structure is
3183 /// to allow clients to efficiently find the function body.
3184 void ModuleBitcodeWriter::writeGlobalValueSymbolTable(
3185   DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3186   // Get the offset of the VST we are writing, and backpatch it into
3187   // the VST forward declaration record.
3188   uint64_t VSTOffset = Stream.GetCurrentBitNo();
3189   // The BitcodeStartBit was the stream offset of the identification block.
3190   VSTOffset -= bitcodeStartBit();
3191   assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
3192   // Note that we add 1 here because the offset is relative to one word
3193   // before the start of the identification block, which was historically
3194   // always the start of the regular bitcode header.
3195   Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32 + 1);
3196 
3197   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3198 
3199   auto Abbv = std::make_shared<BitCodeAbbrev>();
3200   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
3201   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
3202   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
3203   unsigned FnEntryAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3204 
3205   for (const Function &F : M) {
3206     uint64_t Record[2];
3207 
3208     if (F.isDeclaration())
3209       continue;
3210 
3211     Record[0] = VE.getValueID(&F);
3212 
3213     // Save the word offset of the function (from the start of the
3214     // actual bitcode written to the stream).
3215     uint64_t BitcodeIndex = FunctionToBitcodeIndex[&F] - bitcodeStartBit();
3216     assert((BitcodeIndex & 31) == 0 && "function block not 32-bit aligned");
3217     // Note that we add 1 here because the offset is relative to one word
3218     // before the start of the identification block, which was historically
3219     // always the start of the regular bitcode header.
3220     Record[1] = BitcodeIndex / 32 + 1;
3221 
3222     Stream.EmitRecord(bitc::VST_CODE_FNENTRY, Record, FnEntryAbbrev);
3223   }
3224 
3225   Stream.ExitBlock();
3226 }
3227 
3228 /// Emit names for arguments, instructions and basic blocks in a function.
3229 void ModuleBitcodeWriter::writeFunctionLevelValueSymbolTable(
3230     const ValueSymbolTable &VST) {
3231   if (VST.empty())
3232     return;
3233 
3234   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3235 
3236   // FIXME: Set up the abbrev, we know how many values there are!
3237   // FIXME: We know if the type names can use 7-bit ascii.
3238   SmallVector<uint64_t, 64> NameVals;
3239 
3240   for (const ValueName &Name : VST) {
3241     // Figure out the encoding to use for the name.
3242     StringEncoding Bits = getStringEncoding(Name.getKey());
3243 
3244     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
3245     NameVals.push_back(VE.getValueID(Name.getValue()));
3246 
3247     // VST_CODE_ENTRY:   [valueid, namechar x N]
3248     // VST_CODE_BBENTRY: [bbid, namechar x N]
3249     unsigned Code;
3250     if (isa<BasicBlock>(Name.getValue())) {
3251       Code = bitc::VST_CODE_BBENTRY;
3252       if (Bits == SE_Char6)
3253         AbbrevToUse = VST_BBENTRY_6_ABBREV;
3254     } else {
3255       Code = bitc::VST_CODE_ENTRY;
3256       if (Bits == SE_Char6)
3257         AbbrevToUse = VST_ENTRY_6_ABBREV;
3258       else if (Bits == SE_Fixed7)
3259         AbbrevToUse = VST_ENTRY_7_ABBREV;
3260     }
3261 
3262     for (const auto P : Name.getKey())
3263       NameVals.push_back((unsigned char)P);
3264 
3265     // Emit the finished record.
3266     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
3267     NameVals.clear();
3268   }
3269 
3270   Stream.ExitBlock();
3271 }
3272 
3273 void ModuleBitcodeWriter::writeUseList(UseListOrder &&Order) {
3274   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
3275   unsigned Code;
3276   if (isa<BasicBlock>(Order.V))
3277     Code = bitc::USELIST_CODE_BB;
3278   else
3279     Code = bitc::USELIST_CODE_DEFAULT;
3280 
3281   SmallVector<uint64_t, 64> Record(Order.Shuffle.begin(), Order.Shuffle.end());
3282   Record.push_back(VE.getValueID(Order.V));
3283   Stream.EmitRecord(Code, Record);
3284 }
3285 
3286 void ModuleBitcodeWriter::writeUseListBlock(const Function *F) {
3287   assert(VE.shouldPreserveUseListOrder() &&
3288          "Expected to be preserving use-list order");
3289 
3290   auto hasMore = [&]() {
3291     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
3292   };
3293   if (!hasMore())
3294     // Nothing to do.
3295     return;
3296 
3297   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
3298   while (hasMore()) {
3299     writeUseList(std::move(VE.UseListOrders.back()));
3300     VE.UseListOrders.pop_back();
3301   }
3302   Stream.ExitBlock();
3303 }
3304 
3305 /// Emit a function body to the module stream.
3306 void ModuleBitcodeWriter::writeFunction(
3307     const Function &F,
3308     DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3309   // Save the bitcode index of the start of this function block for recording
3310   // in the VST.
3311   FunctionToBitcodeIndex[&F] = Stream.GetCurrentBitNo();
3312 
3313   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
3314   VE.incorporateFunction(F);
3315 
3316   SmallVector<unsigned, 64> Vals;
3317 
3318   // Emit the number of basic blocks, so the reader can create them ahead of
3319   // time.
3320   Vals.push_back(VE.getBasicBlocks().size());
3321   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
3322   Vals.clear();
3323 
3324   // If there are function-local constants, emit them now.
3325   unsigned CstStart, CstEnd;
3326   VE.getFunctionConstantRange(CstStart, CstEnd);
3327   writeConstants(CstStart, CstEnd, false);
3328 
3329   // If there is function-local metadata, emit it now.
3330   writeFunctionMetadata(F);
3331 
3332   // Keep a running idea of what the instruction ID is.
3333   unsigned InstID = CstEnd;
3334 
3335   bool NeedsMetadataAttachment = F.hasMetadata();
3336 
3337   DILocation *LastDL = nullptr;
3338   // Finally, emit all the instructions, in order.
3339   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
3340     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
3341          I != E; ++I) {
3342       writeInstruction(*I, InstID, Vals);
3343 
3344       if (!I->getType()->isVoidTy())
3345         ++InstID;
3346 
3347       // If the instruction has metadata, write a metadata attachment later.
3348       NeedsMetadataAttachment |= I->hasMetadataOtherThanDebugLoc();
3349 
3350       // If the instruction has a debug location, emit it.
3351       DILocation *DL = I->getDebugLoc();
3352       if (!DL)
3353         continue;
3354 
3355       if (DL == LastDL) {
3356         // Just repeat the same debug loc as last time.
3357         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
3358         continue;
3359       }
3360 
3361       Vals.push_back(DL->getLine());
3362       Vals.push_back(DL->getColumn());
3363       Vals.push_back(VE.getMetadataOrNullID(DL->getScope()));
3364       Vals.push_back(VE.getMetadataOrNullID(DL->getInlinedAt()));
3365       Vals.push_back(DL->isImplicitCode());
3366       Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
3367       Vals.clear();
3368 
3369       LastDL = DL;
3370     }
3371 
3372   // Emit names for all the instructions etc.
3373   if (auto *Symtab = F.getValueSymbolTable())
3374     writeFunctionLevelValueSymbolTable(*Symtab);
3375 
3376   if (NeedsMetadataAttachment)
3377     writeFunctionMetadataAttachment(F);
3378   if (VE.shouldPreserveUseListOrder())
3379     writeUseListBlock(&F);
3380   VE.purgeFunction();
3381   Stream.ExitBlock();
3382 }
3383 
3384 // Emit blockinfo, which defines the standard abbreviations etc.
3385 void ModuleBitcodeWriter::writeBlockInfo() {
3386   // We only want to emit block info records for blocks that have multiple
3387   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
3388   // Other blocks can define their abbrevs inline.
3389   Stream.EnterBlockInfoBlock();
3390 
3391   { // 8-bit fixed-width VST_CODE_ENTRY/VST_CODE_BBENTRY strings.
3392     auto Abbv = std::make_shared<BitCodeAbbrev>();
3393     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
3394     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3395     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3396     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3397     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3398         VST_ENTRY_8_ABBREV)
3399       llvm_unreachable("Unexpected abbrev ordering!");
3400   }
3401 
3402   { // 7-bit fixed width VST_CODE_ENTRY strings.
3403     auto Abbv = std::make_shared<BitCodeAbbrev>();
3404     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3405     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3406     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3407     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3408     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3409         VST_ENTRY_7_ABBREV)
3410       llvm_unreachable("Unexpected abbrev ordering!");
3411   }
3412   { // 6-bit char6 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::Char6));
3418     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3419         VST_ENTRY_6_ABBREV)
3420       llvm_unreachable("Unexpected abbrev ordering!");
3421   }
3422   { // 6-bit char6 VST_CODE_BBENTRY strings.
3423     auto Abbv = std::make_shared<BitCodeAbbrev>();
3424     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
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_BBENTRY_6_ABBREV)
3430       llvm_unreachable("Unexpected abbrev ordering!");
3431   }
3432 
3433   { // SETTYPE abbrev for CONSTANTS_BLOCK.
3434     auto Abbv = std::make_shared<BitCodeAbbrev>();
3435     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
3436     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
3437                               VE.computeBitsRequiredForTypeIndicies()));
3438     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3439         CONSTANTS_SETTYPE_ABBREV)
3440       llvm_unreachable("Unexpected abbrev ordering!");
3441   }
3442 
3443   { // INTEGER abbrev for CONSTANTS_BLOCK.
3444     auto Abbv = std::make_shared<BitCodeAbbrev>();
3445     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
3446     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3447     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3448         CONSTANTS_INTEGER_ABBREV)
3449       llvm_unreachable("Unexpected abbrev ordering!");
3450   }
3451 
3452   { // CE_CAST abbrev for CONSTANTS_BLOCK.
3453     auto Abbv = std::make_shared<BitCodeAbbrev>();
3454     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
3455     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
3456     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
3457                               VE.computeBitsRequiredForTypeIndicies()));
3458     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
3459 
3460     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3461         CONSTANTS_CE_CAST_Abbrev)
3462       llvm_unreachable("Unexpected abbrev ordering!");
3463   }
3464   { // NULL abbrev for CONSTANTS_BLOCK.
3465     auto Abbv = std::make_shared<BitCodeAbbrev>();
3466     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
3467     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3468         CONSTANTS_NULL_Abbrev)
3469       llvm_unreachable("Unexpected abbrev ordering!");
3470   }
3471 
3472   // FIXME: This should only use space for first class types!
3473 
3474   { // INST_LOAD abbrev for FUNCTION_BLOCK.
3475     auto Abbv = std::make_shared<BitCodeAbbrev>();
3476     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
3477     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
3478     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
3479                               VE.computeBitsRequiredForTypeIndicies()));
3480     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
3481     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
3482     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3483         FUNCTION_INST_LOAD_ABBREV)
3484       llvm_unreachable("Unexpected abbrev ordering!");
3485   }
3486   { // INST_UNOP abbrev for FUNCTION_BLOCK.
3487     auto Abbv = std::make_shared<BitCodeAbbrev>();
3488     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3489     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3490     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3491     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3492         FUNCTION_INST_UNOP_ABBREV)
3493       llvm_unreachable("Unexpected abbrev ordering!");
3494   }
3495   { // INST_UNOP_FLAGS abbrev for FUNCTION_BLOCK.
3496     auto Abbv = std::make_shared<BitCodeAbbrev>();
3497     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3498     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3499     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3500     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3501     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3502         FUNCTION_INST_UNOP_FLAGS_ABBREV)
3503       llvm_unreachable("Unexpected abbrev ordering!");
3504   }
3505   { // INST_BINOP abbrev for FUNCTION_BLOCK.
3506     auto Abbv = std::make_shared<BitCodeAbbrev>();
3507     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3508     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3509     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3510     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3511     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3512         FUNCTION_INST_BINOP_ABBREV)
3513       llvm_unreachable("Unexpected abbrev ordering!");
3514   }
3515   { // INST_BINOP_FLAGS 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     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3522     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3523         FUNCTION_INST_BINOP_FLAGS_ABBREV)
3524       llvm_unreachable("Unexpected abbrev ordering!");
3525   }
3526   { // INST_CAST abbrev for FUNCTION_BLOCK.
3527     auto Abbv = std::make_shared<BitCodeAbbrev>();
3528     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
3529     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
3530     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
3531                               VE.computeBitsRequiredForTypeIndicies()));
3532     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
3533     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3534         FUNCTION_INST_CAST_ABBREV)
3535       llvm_unreachable("Unexpected abbrev ordering!");
3536   }
3537 
3538   { // INST_RET abbrev for FUNCTION_BLOCK.
3539     auto Abbv = std::make_shared<BitCodeAbbrev>();
3540     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3541     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3542         FUNCTION_INST_RET_VOID_ABBREV)
3543       llvm_unreachable("Unexpected abbrev ordering!");
3544   }
3545   { // INST_RET abbrev for FUNCTION_BLOCK.
3546     auto Abbv = std::make_shared<BitCodeAbbrev>();
3547     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3548     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
3549     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3550         FUNCTION_INST_RET_VAL_ABBREV)
3551       llvm_unreachable("Unexpected abbrev ordering!");
3552   }
3553   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
3554     auto Abbv = std::make_shared<BitCodeAbbrev>();
3555     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
3556     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3557         FUNCTION_INST_UNREACHABLE_ABBREV)
3558       llvm_unreachable("Unexpected abbrev ordering!");
3559   }
3560   {
3561     auto Abbv = std::make_shared<BitCodeAbbrev>();
3562     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_GEP));
3563     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
3564     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, // dest ty
3565                               Log2_32_Ceil(VE.getTypes().size() + 1)));
3566     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3567     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
3568     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3569         FUNCTION_INST_GEP_ABBREV)
3570       llvm_unreachable("Unexpected abbrev ordering!");
3571   }
3572 
3573   Stream.ExitBlock();
3574 }
3575 
3576 /// Write the module path strings, currently only used when generating
3577 /// a combined index file.
3578 void IndexBitcodeWriter::writeModStrings() {
3579   Stream.EnterSubblock(bitc::MODULE_STRTAB_BLOCK_ID, 3);
3580 
3581   // TODO: See which abbrev sizes we actually need to emit
3582 
3583   // 8-bit fixed-width MST_ENTRY strings.
3584   auto Abbv = std::make_shared<BitCodeAbbrev>();
3585   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3586   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3587   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3588   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3589   unsigned Abbrev8Bit = Stream.EmitAbbrev(std::move(Abbv));
3590 
3591   // 7-bit fixed width MST_ENTRY strings.
3592   Abbv = std::make_shared<BitCodeAbbrev>();
3593   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3594   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3595   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3596   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3597   unsigned Abbrev7Bit = Stream.EmitAbbrev(std::move(Abbv));
3598 
3599   // 6-bit char6 MST_ENTRY strings.
3600   Abbv = std::make_shared<BitCodeAbbrev>();
3601   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3602   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3603   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3604   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3605   unsigned Abbrev6Bit = Stream.EmitAbbrev(std::move(Abbv));
3606 
3607   // Module Hash, 160 bits SHA1. Optionally, emitted after each MST_CODE_ENTRY.
3608   Abbv = std::make_shared<BitCodeAbbrev>();
3609   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_HASH));
3610   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3611   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3612   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3613   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3614   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3615   unsigned AbbrevHash = Stream.EmitAbbrev(std::move(Abbv));
3616 
3617   SmallVector<unsigned, 64> Vals;
3618   forEachModule(
3619       [&](const StringMapEntry<std::pair<uint64_t, ModuleHash>> &MPSE) {
3620         StringRef Key = MPSE.getKey();
3621         const auto &Value = MPSE.getValue();
3622         StringEncoding Bits = getStringEncoding(Key);
3623         unsigned AbbrevToUse = Abbrev8Bit;
3624         if (Bits == SE_Char6)
3625           AbbrevToUse = Abbrev6Bit;
3626         else if (Bits == SE_Fixed7)
3627           AbbrevToUse = Abbrev7Bit;
3628 
3629         Vals.push_back(Value.first);
3630         Vals.append(Key.begin(), Key.end());
3631 
3632         // Emit the finished record.
3633         Stream.EmitRecord(bitc::MST_CODE_ENTRY, Vals, AbbrevToUse);
3634 
3635         // Emit an optional hash for the module now
3636         const auto &Hash = Value.second;
3637         if (llvm::any_of(Hash, [](uint32_t H) { return H; })) {
3638           Vals.assign(Hash.begin(), Hash.end());
3639           // Emit the hash record.
3640           Stream.EmitRecord(bitc::MST_CODE_HASH, Vals, AbbrevHash);
3641         }
3642 
3643         Vals.clear();
3644       });
3645   Stream.ExitBlock();
3646 }
3647 
3648 /// Write the function type metadata related records that need to appear before
3649 /// a function summary entry (whether per-module or combined).
3650 template <typename Fn>
3651 static void writeFunctionTypeMetadataRecords(BitstreamWriter &Stream,
3652                                              FunctionSummary *FS,
3653                                              Fn GetValueID) {
3654   if (!FS->type_tests().empty())
3655     Stream.EmitRecord(bitc::FS_TYPE_TESTS, FS->type_tests());
3656 
3657   SmallVector<uint64_t, 64> Record;
3658 
3659   auto WriteVFuncIdVec = [&](uint64_t Ty,
3660                              ArrayRef<FunctionSummary::VFuncId> VFs) {
3661     if (VFs.empty())
3662       return;
3663     Record.clear();
3664     for (auto &VF : VFs) {
3665       Record.push_back(VF.GUID);
3666       Record.push_back(VF.Offset);
3667     }
3668     Stream.EmitRecord(Ty, Record);
3669   };
3670 
3671   WriteVFuncIdVec(bitc::FS_TYPE_TEST_ASSUME_VCALLS,
3672                   FS->type_test_assume_vcalls());
3673   WriteVFuncIdVec(bitc::FS_TYPE_CHECKED_LOAD_VCALLS,
3674                   FS->type_checked_load_vcalls());
3675 
3676   auto WriteConstVCallVec = [&](uint64_t Ty,
3677                                 ArrayRef<FunctionSummary::ConstVCall> VCs) {
3678     for (auto &VC : VCs) {
3679       Record.clear();
3680       Record.push_back(VC.VFunc.GUID);
3681       Record.push_back(VC.VFunc.Offset);
3682       llvm::append_range(Record, VC.Args);
3683       Stream.EmitRecord(Ty, Record);
3684     }
3685   };
3686 
3687   WriteConstVCallVec(bitc::FS_TYPE_TEST_ASSUME_CONST_VCALL,
3688                      FS->type_test_assume_const_vcalls());
3689   WriteConstVCallVec(bitc::FS_TYPE_CHECKED_LOAD_CONST_VCALL,
3690                      FS->type_checked_load_const_vcalls());
3691 
3692   auto WriteRange = [&](ConstantRange Range) {
3693     Range = Range.sextOrTrunc(FunctionSummary::ParamAccess::RangeWidth);
3694     assert(Range.getLower().getNumWords() == 1);
3695     assert(Range.getUpper().getNumWords() == 1);
3696     emitSignedInt64(Record, *Range.getLower().getRawData());
3697     emitSignedInt64(Record, *Range.getUpper().getRawData());
3698   };
3699 
3700   if (!FS->paramAccesses().empty()) {
3701     Record.clear();
3702     for (auto &Arg : FS->paramAccesses()) {
3703       size_t UndoSize = Record.size();
3704       Record.push_back(Arg.ParamNo);
3705       WriteRange(Arg.Use);
3706       Record.push_back(Arg.Calls.size());
3707       for (auto &Call : Arg.Calls) {
3708         Record.push_back(Call.ParamNo);
3709         Optional<unsigned> ValueID = GetValueID(Call.Callee);
3710         if (!ValueID) {
3711           // If ValueID is unknown we can't drop just this call, we must drop
3712           // entire parameter.
3713           Record.resize(UndoSize);
3714           break;
3715         }
3716         Record.push_back(*ValueID);
3717         WriteRange(Call.Offsets);
3718       }
3719     }
3720     if (!Record.empty())
3721       Stream.EmitRecord(bitc::FS_PARAM_ACCESS, Record);
3722   }
3723 }
3724 
3725 /// Collect type IDs from type tests used by function.
3726 static void
3727 getReferencedTypeIds(FunctionSummary *FS,
3728                      std::set<GlobalValue::GUID> &ReferencedTypeIds) {
3729   if (!FS->type_tests().empty())
3730     for (auto &TT : FS->type_tests())
3731       ReferencedTypeIds.insert(TT);
3732 
3733   auto GetReferencedTypesFromVFuncIdVec =
3734       [&](ArrayRef<FunctionSummary::VFuncId> VFs) {
3735         for (auto &VF : VFs)
3736           ReferencedTypeIds.insert(VF.GUID);
3737       };
3738 
3739   GetReferencedTypesFromVFuncIdVec(FS->type_test_assume_vcalls());
3740   GetReferencedTypesFromVFuncIdVec(FS->type_checked_load_vcalls());
3741 
3742   auto GetReferencedTypesFromConstVCallVec =
3743       [&](ArrayRef<FunctionSummary::ConstVCall> VCs) {
3744         for (auto &VC : VCs)
3745           ReferencedTypeIds.insert(VC.VFunc.GUID);
3746       };
3747 
3748   GetReferencedTypesFromConstVCallVec(FS->type_test_assume_const_vcalls());
3749   GetReferencedTypesFromConstVCallVec(FS->type_checked_load_const_vcalls());
3750 }
3751 
3752 static void writeWholeProgramDevirtResolutionByArg(
3753     SmallVector<uint64_t, 64> &NameVals, const std::vector<uint64_t> &args,
3754     const WholeProgramDevirtResolution::ByArg &ByArg) {
3755   NameVals.push_back(args.size());
3756   llvm::append_range(NameVals, args);
3757 
3758   NameVals.push_back(ByArg.TheKind);
3759   NameVals.push_back(ByArg.Info);
3760   NameVals.push_back(ByArg.Byte);
3761   NameVals.push_back(ByArg.Bit);
3762 }
3763 
3764 static void writeWholeProgramDevirtResolution(
3765     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3766     uint64_t Id, const WholeProgramDevirtResolution &Wpd) {
3767   NameVals.push_back(Id);
3768 
3769   NameVals.push_back(Wpd.TheKind);
3770   NameVals.push_back(StrtabBuilder.add(Wpd.SingleImplName));
3771   NameVals.push_back(Wpd.SingleImplName.size());
3772 
3773   NameVals.push_back(Wpd.ResByArg.size());
3774   for (auto &A : Wpd.ResByArg)
3775     writeWholeProgramDevirtResolutionByArg(NameVals, A.first, A.second);
3776 }
3777 
3778 static void writeTypeIdSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
3779                                      StringTableBuilder &StrtabBuilder,
3780                                      const std::string &Id,
3781                                      const TypeIdSummary &Summary) {
3782   NameVals.push_back(StrtabBuilder.add(Id));
3783   NameVals.push_back(Id.size());
3784 
3785   NameVals.push_back(Summary.TTRes.TheKind);
3786   NameVals.push_back(Summary.TTRes.SizeM1BitWidth);
3787   NameVals.push_back(Summary.TTRes.AlignLog2);
3788   NameVals.push_back(Summary.TTRes.SizeM1);
3789   NameVals.push_back(Summary.TTRes.BitMask);
3790   NameVals.push_back(Summary.TTRes.InlineBits);
3791 
3792   for (auto &W : Summary.WPDRes)
3793     writeWholeProgramDevirtResolution(NameVals, StrtabBuilder, W.first,
3794                                       W.second);
3795 }
3796 
3797 static void writeTypeIdCompatibleVtableSummaryRecord(
3798     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3799     const std::string &Id, const TypeIdCompatibleVtableInfo &Summary,
3800     ValueEnumerator &VE) {
3801   NameVals.push_back(StrtabBuilder.add(Id));
3802   NameVals.push_back(Id.size());
3803 
3804   for (auto &P : Summary) {
3805     NameVals.push_back(P.AddressPointOffset);
3806     NameVals.push_back(VE.getValueID(P.VTableVI.getValue()));
3807   }
3808 }
3809 
3810 // Helper to emit a single function summary record.
3811 void ModuleBitcodeWriterBase::writePerModuleFunctionSummaryRecord(
3812     SmallVector<uint64_t, 64> &NameVals, GlobalValueSummary *Summary,
3813     unsigned ValueID, unsigned FSCallsAbbrev, unsigned FSCallsProfileAbbrev,
3814     const Function &F) {
3815   NameVals.push_back(ValueID);
3816 
3817   FunctionSummary *FS = cast<FunctionSummary>(Summary);
3818 
3819   writeFunctionTypeMetadataRecords(
3820       Stream, FS, [&](const ValueInfo &VI) -> Optional<unsigned> {
3821         return {VE.getValueID(VI.getValue())};
3822       });
3823 
3824   auto SpecialRefCnts = FS->specialRefCounts();
3825   NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
3826   NameVals.push_back(FS->instCount());
3827   NameVals.push_back(getEncodedFFlags(FS->fflags()));
3828   NameVals.push_back(FS->refs().size());
3829   NameVals.push_back(SpecialRefCnts.first);  // rorefcnt
3830   NameVals.push_back(SpecialRefCnts.second); // worefcnt
3831 
3832   for (auto &RI : FS->refs())
3833     NameVals.push_back(VE.getValueID(RI.getValue()));
3834 
3835   bool HasProfileData =
3836       F.hasProfileData() || ForceSummaryEdgesCold != FunctionSummary::FSHT_None;
3837   for (auto &ECI : FS->calls()) {
3838     NameVals.push_back(getValueId(ECI.first));
3839     if (HasProfileData)
3840       NameVals.push_back(static_cast<uint8_t>(ECI.second.Hotness));
3841     else if (WriteRelBFToSummary)
3842       NameVals.push_back(ECI.second.RelBlockFreq);
3843   }
3844 
3845   unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
3846   unsigned Code =
3847       (HasProfileData ? bitc::FS_PERMODULE_PROFILE
3848                       : (WriteRelBFToSummary ? bitc::FS_PERMODULE_RELBF
3849                                              : bitc::FS_PERMODULE));
3850 
3851   // Emit the finished record.
3852   Stream.EmitRecord(Code, NameVals, FSAbbrev);
3853   NameVals.clear();
3854 }
3855 
3856 // Collect the global value references in the given variable's initializer,
3857 // and emit them in a summary record.
3858 void ModuleBitcodeWriterBase::writeModuleLevelReferences(
3859     const GlobalVariable &V, SmallVector<uint64_t, 64> &NameVals,
3860     unsigned FSModRefsAbbrev, unsigned FSModVTableRefsAbbrev) {
3861   auto VI = Index->getValueInfo(V.getGUID());
3862   if (!VI || VI.getSummaryList().empty()) {
3863     // Only declarations should not have a summary (a declaration might however
3864     // have a summary if the def was in module level asm).
3865     assert(V.isDeclaration());
3866     return;
3867   }
3868   auto *Summary = VI.getSummaryList()[0].get();
3869   NameVals.push_back(VE.getValueID(&V));
3870   GlobalVarSummary *VS = cast<GlobalVarSummary>(Summary);
3871   NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
3872   NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
3873 
3874   auto VTableFuncs = VS->vTableFuncs();
3875   if (!VTableFuncs.empty())
3876     NameVals.push_back(VS->refs().size());
3877 
3878   unsigned SizeBeforeRefs = NameVals.size();
3879   for (auto &RI : VS->refs())
3880     NameVals.push_back(VE.getValueID(RI.getValue()));
3881   // Sort the refs for determinism output, the vector returned by FS->refs() has
3882   // been initialized from a DenseSet.
3883   llvm::sort(drop_begin(NameVals, SizeBeforeRefs));
3884 
3885   if (VTableFuncs.empty())
3886     Stream.EmitRecord(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS, NameVals,
3887                       FSModRefsAbbrev);
3888   else {
3889     // VTableFuncs pairs should already be sorted by offset.
3890     for (auto &P : VTableFuncs) {
3891       NameVals.push_back(VE.getValueID(P.FuncVI.getValue()));
3892       NameVals.push_back(P.VTableOffset);
3893     }
3894 
3895     Stream.EmitRecord(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS, NameVals,
3896                       FSModVTableRefsAbbrev);
3897   }
3898   NameVals.clear();
3899 }
3900 
3901 /// Emit the per-module summary section alongside the rest of
3902 /// the module's bitcode.
3903 void ModuleBitcodeWriterBase::writePerModuleGlobalValueSummary() {
3904   // By default we compile with ThinLTO if the module has a summary, but the
3905   // client can request full LTO with a module flag.
3906   bool IsThinLTO = true;
3907   if (auto *MD =
3908           mdconst::extract_or_null<ConstantInt>(M.getModuleFlag("ThinLTO")))
3909     IsThinLTO = MD->getZExtValue();
3910   Stream.EnterSubblock(IsThinLTO ? bitc::GLOBALVAL_SUMMARY_BLOCK_ID
3911                                  : bitc::FULL_LTO_GLOBALVAL_SUMMARY_BLOCK_ID,
3912                        4);
3913 
3914   Stream.EmitRecord(
3915       bitc::FS_VERSION,
3916       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
3917 
3918   // Write the index flags.
3919   uint64_t Flags = 0;
3920   // Bits 1-3 are set only in the combined index, skip them.
3921   if (Index->enableSplitLTOUnit())
3922     Flags |= 0x8;
3923   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Flags});
3924 
3925   if (Index->begin() == Index->end()) {
3926     Stream.ExitBlock();
3927     return;
3928   }
3929 
3930   for (const auto &GVI : valueIds()) {
3931     Stream.EmitRecord(bitc::FS_VALUE_GUID,
3932                       ArrayRef<uint64_t>{GVI.second, GVI.first});
3933   }
3934 
3935   // Abbrev for FS_PERMODULE_PROFILE.
3936   auto Abbv = std::make_shared<BitCodeAbbrev>();
3937   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_PROFILE));
3938   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3939   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3940   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3941   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3942   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3943   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
3944   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
3945   // numrefs x valueid, n x (valueid, hotness)
3946   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3947   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3948   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3949 
3950   // Abbrev for FS_PERMODULE or FS_PERMODULE_RELBF.
3951   Abbv = std::make_shared<BitCodeAbbrev>();
3952   if (WriteRelBFToSummary)
3953     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_RELBF));
3954   else
3955     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE));
3956   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3957   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3958   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3959   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3960   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3961   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
3962   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
3963   // numrefs x valueid, n x (valueid [, rel_block_freq])
3964   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3965   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3966   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3967 
3968   // Abbrev for FS_PERMODULE_GLOBALVAR_INIT_REFS.
3969   Abbv = std::make_shared<BitCodeAbbrev>();
3970   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS));
3971   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
3972   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
3973   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));  // valueids
3974   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3975   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3976 
3977   // Abbrev for FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS.
3978   Abbv = std::make_shared<BitCodeAbbrev>();
3979   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS));
3980   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
3981   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
3982   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numrefs
3983   // numrefs x valueid, n x (valueid , offset)
3984   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3985   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3986   unsigned FSModVTableRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3987 
3988   // Abbrev for FS_ALIAS.
3989   Abbv = std::make_shared<BitCodeAbbrev>();
3990   Abbv->Add(BitCodeAbbrevOp(bitc::FS_ALIAS));
3991   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3992   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3993   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3994   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3995 
3996   // Abbrev for FS_TYPE_ID_METADATA
3997   Abbv = std::make_shared<BitCodeAbbrev>();
3998   Abbv->Add(BitCodeAbbrevOp(bitc::FS_TYPE_ID_METADATA));
3999   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid strtab index
4000   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid length
4001   // n x (valueid , offset)
4002   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4003   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4004   unsigned TypeIdCompatibleVtableAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4005 
4006   SmallVector<uint64_t, 64> NameVals;
4007   // Iterate over the list of functions instead of the Index to
4008   // ensure the ordering is stable.
4009   for (const Function &F : M) {
4010     // Summary emission does not support anonymous functions, they have to
4011     // renamed using the anonymous function renaming pass.
4012     if (!F.hasName())
4013       report_fatal_error("Unexpected anonymous function when writing summary");
4014 
4015     ValueInfo VI = Index->getValueInfo(F.getGUID());
4016     if (!VI || VI.getSummaryList().empty()) {
4017       // Only declarations should not have a summary (a declaration might
4018       // however have a summary if the def was in module level asm).
4019       assert(F.isDeclaration());
4020       continue;
4021     }
4022     auto *Summary = VI.getSummaryList()[0].get();
4023     writePerModuleFunctionSummaryRecord(NameVals, Summary, VE.getValueID(&F),
4024                                         FSCallsAbbrev, FSCallsProfileAbbrev, F);
4025   }
4026 
4027   // Capture references from GlobalVariable initializers, which are outside
4028   // of a function scope.
4029   for (const GlobalVariable &G : M.globals())
4030     writeModuleLevelReferences(G, NameVals, FSModRefsAbbrev,
4031                                FSModVTableRefsAbbrev);
4032 
4033   for (const GlobalAlias &A : M.aliases()) {
4034     auto *Aliasee = A.getBaseObject();
4035     if (!Aliasee->hasName())
4036       // Nameless function don't have an entry in the summary, skip it.
4037       continue;
4038     auto AliasId = VE.getValueID(&A);
4039     auto AliaseeId = VE.getValueID(Aliasee);
4040     NameVals.push_back(AliasId);
4041     auto *Summary = Index->getGlobalValueSummary(A);
4042     AliasSummary *AS = cast<AliasSummary>(Summary);
4043     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
4044     NameVals.push_back(AliaseeId);
4045     Stream.EmitRecord(bitc::FS_ALIAS, NameVals, FSAliasAbbrev);
4046     NameVals.clear();
4047   }
4048 
4049   for (auto &S : Index->typeIdCompatibleVtableMap()) {
4050     writeTypeIdCompatibleVtableSummaryRecord(NameVals, StrtabBuilder, S.first,
4051                                              S.second, VE);
4052     Stream.EmitRecord(bitc::FS_TYPE_ID_METADATA, NameVals,
4053                       TypeIdCompatibleVtableAbbrev);
4054     NameVals.clear();
4055   }
4056 
4057   Stream.EmitRecord(bitc::FS_BLOCK_COUNT,
4058                     ArrayRef<uint64_t>{Index->getBlockCount()});
4059 
4060   Stream.ExitBlock();
4061 }
4062 
4063 /// Emit the combined summary section into the combined index file.
4064 void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
4065   Stream.EnterSubblock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID, 3);
4066   Stream.EmitRecord(
4067       bitc::FS_VERSION,
4068       ArrayRef<uint64_t>{ModuleSummaryIndex::BitcodeSummaryVersion});
4069 
4070   // Write the index flags.
4071   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Index.getFlags()});
4072 
4073   for (const auto &GVI : valueIds()) {
4074     Stream.EmitRecord(bitc::FS_VALUE_GUID,
4075                       ArrayRef<uint64_t>{GVI.second, GVI.first});
4076   }
4077 
4078   // Abbrev for FS_COMBINED.
4079   auto Abbv = std::make_shared<BitCodeAbbrev>();
4080   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED));
4081   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4082   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4083   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4084   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4085   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4086   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
4087   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4088   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4089   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4090   // numrefs x valueid, n x (valueid)
4091   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4092   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4093   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4094 
4095   // Abbrev for FS_COMBINED_PROFILE.
4096   Abbv = std::make_shared<BitCodeAbbrev>();
4097   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_PROFILE));
4098   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4099   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4100   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4101   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
4102   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
4103   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
4104   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
4105   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
4106   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
4107   // numrefs x valueid, n x (valueid, hotness)
4108   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4109   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4110   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4111 
4112   // Abbrev for FS_COMBINED_GLOBALVAR_INIT_REFS.
4113   Abbv = std::make_shared<BitCodeAbbrev>();
4114   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS));
4115   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
4116   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
4117   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
4118   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));    // valueids
4119   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
4120   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4121 
4122   // Abbrev for FS_COMBINED_ALIAS.
4123   Abbv = std::make_shared<BitCodeAbbrev>();
4124   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_ALIAS));
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::VBR, 8));   // valueid
4129   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4130 
4131   // The aliases are emitted as a post-pass, and will point to the value
4132   // id of the aliasee. Save them in a vector for post-processing.
4133   SmallVector<AliasSummary *, 64> Aliases;
4134 
4135   // Save the value id for each summary for alias emission.
4136   DenseMap<const GlobalValueSummary *, unsigned> SummaryToValueIdMap;
4137 
4138   SmallVector<uint64_t, 64> NameVals;
4139 
4140   // Set that will be populated during call to writeFunctionTypeMetadataRecords
4141   // with the type ids referenced by this index file.
4142   std::set<GlobalValue::GUID> ReferencedTypeIds;
4143 
4144   // For local linkage, we also emit the original name separately
4145   // immediately after the record.
4146   auto MaybeEmitOriginalName = [&](GlobalValueSummary &S) {
4147     if (!GlobalValue::isLocalLinkage(S.linkage()))
4148       return;
4149     NameVals.push_back(S.getOriginalName());
4150     Stream.EmitRecord(bitc::FS_COMBINED_ORIGINAL_NAME, NameVals);
4151     NameVals.clear();
4152   };
4153 
4154   std::set<GlobalValue::GUID> DefOrUseGUIDs;
4155   forEachSummary([&](GVInfo I, bool IsAliasee) {
4156     GlobalValueSummary *S = I.second;
4157     assert(S);
4158     DefOrUseGUIDs.insert(I.first);
4159     for (const ValueInfo &VI : S->refs())
4160       DefOrUseGUIDs.insert(VI.getGUID());
4161 
4162     auto ValueId = getValueId(I.first);
4163     assert(ValueId);
4164     SummaryToValueIdMap[S] = *ValueId;
4165 
4166     // If this is invoked for an aliasee, we want to record the above
4167     // mapping, but then not emit a summary entry (if the aliasee is
4168     // to be imported, we will invoke this separately with IsAliasee=false).
4169     if (IsAliasee)
4170       return;
4171 
4172     if (auto *AS = dyn_cast<AliasSummary>(S)) {
4173       // Will process aliases as a post-pass because the reader wants all
4174       // global to be loaded first.
4175       Aliases.push_back(AS);
4176       return;
4177     }
4178 
4179     if (auto *VS = dyn_cast<GlobalVarSummary>(S)) {
4180       NameVals.push_back(*ValueId);
4181       NameVals.push_back(Index.getModuleId(VS->modulePath()));
4182       NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
4183       NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
4184       for (auto &RI : VS->refs()) {
4185         auto RefValueId = getValueId(RI.getGUID());
4186         if (!RefValueId)
4187           continue;
4188         NameVals.push_back(*RefValueId);
4189       }
4190 
4191       // Emit the finished record.
4192       Stream.EmitRecord(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS, NameVals,
4193                         FSModRefsAbbrev);
4194       NameVals.clear();
4195       MaybeEmitOriginalName(*S);
4196       return;
4197     }
4198 
4199     auto GetValueId = [&](const ValueInfo &VI) -> Optional<unsigned> {
4200       GlobalValue::GUID GUID = VI.getGUID();
4201       Optional<unsigned> CallValueId = getValueId(GUID);
4202       if (CallValueId)
4203         return CallValueId;
4204       // For SamplePGO, the indirect call targets for local functions will
4205       // have its original name annotated in profile. We try to find the
4206       // corresponding PGOFuncName as the GUID.
4207       GUID = Index.getGUIDFromOriginalID(GUID);
4208       if (!GUID)
4209         return None;
4210       CallValueId = getValueId(GUID);
4211       if (!CallValueId)
4212         return None;
4213       // The mapping from OriginalId to GUID may return a GUID
4214       // that corresponds to a static variable. Filter it out here.
4215       // This can happen when
4216       // 1) There is a call to a library function which does not have
4217       // a CallValidId;
4218       // 2) There is a static variable with the  OriginalGUID identical
4219       // to the GUID of the library function in 1);
4220       // When this happens, the logic for SamplePGO kicks in and
4221       // the static variable in 2) will be found, which needs to be
4222       // filtered out.
4223       auto *GVSum = Index.getGlobalValueSummary(GUID, false);
4224       if (GVSum && GVSum->getSummaryKind() == GlobalValueSummary::GlobalVarKind)
4225         return None;
4226       return CallValueId;
4227     };
4228 
4229     auto *FS = cast<FunctionSummary>(S);
4230     writeFunctionTypeMetadataRecords(Stream, FS, GetValueId);
4231     getReferencedTypeIds(FS, ReferencedTypeIds);
4232 
4233     NameVals.push_back(*ValueId);
4234     NameVals.push_back(Index.getModuleId(FS->modulePath()));
4235     NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
4236     NameVals.push_back(FS->instCount());
4237     NameVals.push_back(getEncodedFFlags(FS->fflags()));
4238     NameVals.push_back(FS->entryCount());
4239 
4240     // Fill in below
4241     NameVals.push_back(0); // numrefs
4242     NameVals.push_back(0); // rorefcnt
4243     NameVals.push_back(0); // worefcnt
4244 
4245     unsigned Count = 0, RORefCnt = 0, WORefCnt = 0;
4246     for (auto &RI : FS->refs()) {
4247       auto RefValueId = getValueId(RI.getGUID());
4248       if (!RefValueId)
4249         continue;
4250       NameVals.push_back(*RefValueId);
4251       if (RI.isReadOnly())
4252         RORefCnt++;
4253       else if (RI.isWriteOnly())
4254         WORefCnt++;
4255       Count++;
4256     }
4257     NameVals[6] = Count;
4258     NameVals[7] = RORefCnt;
4259     NameVals[8] = WORefCnt;
4260 
4261     bool HasProfileData = false;
4262     for (auto &EI : FS->calls()) {
4263       HasProfileData |=
4264           EI.second.getHotness() != CalleeInfo::HotnessType::Unknown;
4265       if (HasProfileData)
4266         break;
4267     }
4268 
4269     for (auto &EI : FS->calls()) {
4270       // If this GUID doesn't have a value id, it doesn't have a function
4271       // summary and we don't need to record any calls to it.
4272       Optional<unsigned> CallValueId = GetValueId(EI.first);
4273       if (!CallValueId)
4274         continue;
4275       NameVals.push_back(*CallValueId);
4276       if (HasProfileData)
4277         NameVals.push_back(static_cast<uint8_t>(EI.second.Hotness));
4278     }
4279 
4280     unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
4281     unsigned Code =
4282         (HasProfileData ? bitc::FS_COMBINED_PROFILE : bitc::FS_COMBINED);
4283 
4284     // Emit the finished record.
4285     Stream.EmitRecord(Code, NameVals, FSAbbrev);
4286     NameVals.clear();
4287     MaybeEmitOriginalName(*S);
4288   });
4289 
4290   for (auto *AS : Aliases) {
4291     auto AliasValueId = SummaryToValueIdMap[AS];
4292     assert(AliasValueId);
4293     NameVals.push_back(AliasValueId);
4294     NameVals.push_back(Index.getModuleId(AS->modulePath()));
4295     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
4296     auto AliaseeValueId = SummaryToValueIdMap[&AS->getAliasee()];
4297     assert(AliaseeValueId);
4298     NameVals.push_back(AliaseeValueId);
4299 
4300     // Emit the finished record.
4301     Stream.EmitRecord(bitc::FS_COMBINED_ALIAS, NameVals, FSAliasAbbrev);
4302     NameVals.clear();
4303     MaybeEmitOriginalName(*AS);
4304 
4305     if (auto *FS = dyn_cast<FunctionSummary>(&AS->getAliasee()))
4306       getReferencedTypeIds(FS, ReferencedTypeIds);
4307   }
4308 
4309   if (!Index.cfiFunctionDefs().empty()) {
4310     for (auto &S : Index.cfiFunctionDefs()) {
4311       if (DefOrUseGUIDs.count(
4312               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4313         NameVals.push_back(StrtabBuilder.add(S));
4314         NameVals.push_back(S.size());
4315       }
4316     }
4317     if (!NameVals.empty()) {
4318       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DEFS, NameVals);
4319       NameVals.clear();
4320     }
4321   }
4322 
4323   if (!Index.cfiFunctionDecls().empty()) {
4324     for (auto &S : Index.cfiFunctionDecls()) {
4325       if (DefOrUseGUIDs.count(
4326               GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(S)))) {
4327         NameVals.push_back(StrtabBuilder.add(S));
4328         NameVals.push_back(S.size());
4329       }
4330     }
4331     if (!NameVals.empty()) {
4332       Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DECLS, NameVals);
4333       NameVals.clear();
4334     }
4335   }
4336 
4337   // Walk the GUIDs that were referenced, and write the
4338   // corresponding type id records.
4339   for (auto &T : ReferencedTypeIds) {
4340     auto TidIter = Index.typeIds().equal_range(T);
4341     for (auto It = TidIter.first; It != TidIter.second; ++It) {
4342       writeTypeIdSummaryRecord(NameVals, StrtabBuilder, It->second.first,
4343                                It->second.second);
4344       Stream.EmitRecord(bitc::FS_TYPE_ID, NameVals);
4345       NameVals.clear();
4346     }
4347   }
4348 
4349   Stream.EmitRecord(bitc::FS_BLOCK_COUNT,
4350                     ArrayRef<uint64_t>{Index.getBlockCount()});
4351 
4352   Stream.ExitBlock();
4353 }
4354 
4355 /// Create the "IDENTIFICATION_BLOCK_ID" containing a single string with the
4356 /// current llvm version, and a record for the epoch number.
4357 static void writeIdentificationBlock(BitstreamWriter &Stream) {
4358   Stream.EnterSubblock(bitc::IDENTIFICATION_BLOCK_ID, 5);
4359 
4360   // Write the "user readable" string identifying the bitcode producer
4361   auto Abbv = std::make_shared<BitCodeAbbrev>();
4362   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_STRING));
4363   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4364   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
4365   auto StringAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4366   writeStringRecord(Stream, bitc::IDENTIFICATION_CODE_STRING,
4367                     "LLVM" LLVM_VERSION_STRING, StringAbbrev);
4368 
4369   // Write the epoch version
4370   Abbv = std::make_shared<BitCodeAbbrev>();
4371   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_EPOCH));
4372   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
4373   auto EpochAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4374   constexpr std::array<unsigned, 1> Vals = {{bitc::BITCODE_CURRENT_EPOCH}};
4375   Stream.EmitRecord(bitc::IDENTIFICATION_CODE_EPOCH, Vals, EpochAbbrev);
4376   Stream.ExitBlock();
4377 }
4378 
4379 void ModuleBitcodeWriter::writeModuleHash(size_t BlockStartPos) {
4380   // Emit the module's hash.
4381   // MODULE_CODE_HASH: [5*i32]
4382   if (GenerateHash) {
4383     uint32_t Vals[5];
4384     Hasher.update(ArrayRef<uint8_t>((const uint8_t *)&(Buffer)[BlockStartPos],
4385                                     Buffer.size() - BlockStartPos));
4386     StringRef Hash = Hasher.result();
4387     for (int Pos = 0; Pos < 20; Pos += 4) {
4388       Vals[Pos / 4] = support::endian::read32be(Hash.data() + Pos);
4389     }
4390 
4391     // Emit the finished record.
4392     Stream.EmitRecord(bitc::MODULE_CODE_HASH, Vals);
4393 
4394     if (ModHash)
4395       // Save the written hash value.
4396       llvm::copy(Vals, std::begin(*ModHash));
4397   }
4398 }
4399 
4400 void ModuleBitcodeWriter::write() {
4401   writeIdentificationBlock(Stream);
4402 
4403   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4404   size_t BlockStartPos = Buffer.size();
4405 
4406   writeModuleVersion();
4407 
4408   // Emit blockinfo, which defines the standard abbreviations etc.
4409   writeBlockInfo();
4410 
4411   // Emit information describing all of the types in the module.
4412   writeTypeTable();
4413 
4414   // Emit information about attribute groups.
4415   writeAttributeGroupTable();
4416 
4417   // Emit information about parameter attributes.
4418   writeAttributeTable();
4419 
4420   writeComdats();
4421 
4422   // Emit top-level description of module, including target triple, inline asm,
4423   // descriptors for global variables, and function prototype info.
4424   writeModuleInfo();
4425 
4426   // Emit constants.
4427   writeModuleConstants();
4428 
4429   // Emit metadata kind names.
4430   writeModuleMetadataKinds();
4431 
4432   // Emit metadata.
4433   writeModuleMetadata();
4434 
4435   // Emit module-level use-lists.
4436   if (VE.shouldPreserveUseListOrder())
4437     writeUseListBlock(nullptr);
4438 
4439   writeOperandBundleTags();
4440   writeSyncScopeNames();
4441 
4442   // Emit function bodies.
4443   DenseMap<const Function *, uint64_t> FunctionToBitcodeIndex;
4444   for (Module::const_iterator F = M.begin(), E = M.end(); F != E; ++F)
4445     if (!F->isDeclaration())
4446       writeFunction(*F, FunctionToBitcodeIndex);
4447 
4448   // Need to write after the above call to WriteFunction which populates
4449   // the summary information in the index.
4450   if (Index)
4451     writePerModuleGlobalValueSummary();
4452 
4453   writeGlobalValueSymbolTable(FunctionToBitcodeIndex);
4454 
4455   writeModuleHash(BlockStartPos);
4456 
4457   Stream.ExitBlock();
4458 }
4459 
4460 static void writeInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
4461                                uint32_t &Position) {
4462   support::endian::write32le(&Buffer[Position], Value);
4463   Position += 4;
4464 }
4465 
4466 /// If generating a bc file on darwin, we have to emit a
4467 /// header and trailer to make it compatible with the system archiver.  To do
4468 /// this we emit the following header, and then emit a trailer that pads the
4469 /// file out to be a multiple of 16 bytes.
4470 ///
4471 /// struct bc_header {
4472 ///   uint32_t Magic;         // 0x0B17C0DE
4473 ///   uint32_t Version;       // Version, currently always 0.
4474 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
4475 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
4476 ///   uint32_t CPUType;       // CPU specifier.
4477 ///   ... potentially more later ...
4478 /// };
4479 static void emitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
4480                                          const Triple &TT) {
4481   unsigned CPUType = ~0U;
4482 
4483   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
4484   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
4485   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
4486   // specific constants here because they are implicitly part of the Darwin ABI.
4487   enum {
4488     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
4489     DARWIN_CPU_TYPE_X86        = 7,
4490     DARWIN_CPU_TYPE_ARM        = 12,
4491     DARWIN_CPU_TYPE_POWERPC    = 18
4492   };
4493 
4494   Triple::ArchType Arch = TT.getArch();
4495   if (Arch == Triple::x86_64)
4496     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
4497   else if (Arch == Triple::x86)
4498     CPUType = DARWIN_CPU_TYPE_X86;
4499   else if (Arch == Triple::ppc)
4500     CPUType = DARWIN_CPU_TYPE_POWERPC;
4501   else if (Arch == Triple::ppc64)
4502     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
4503   else if (Arch == Triple::arm || Arch == Triple::thumb)
4504     CPUType = DARWIN_CPU_TYPE_ARM;
4505 
4506   // Traditional Bitcode starts after header.
4507   assert(Buffer.size() >= BWH_HeaderSize &&
4508          "Expected header size to be reserved");
4509   unsigned BCOffset = BWH_HeaderSize;
4510   unsigned BCSize = Buffer.size() - BWH_HeaderSize;
4511 
4512   // Write the magic and version.
4513   unsigned Position = 0;
4514   writeInt32ToBuffer(0x0B17C0DE, Buffer, Position);
4515   writeInt32ToBuffer(0, Buffer, Position); // Version.
4516   writeInt32ToBuffer(BCOffset, Buffer, Position);
4517   writeInt32ToBuffer(BCSize, Buffer, Position);
4518   writeInt32ToBuffer(CPUType, Buffer, Position);
4519 
4520   // If the file is not a multiple of 16 bytes, insert dummy padding.
4521   while (Buffer.size() & 15)
4522     Buffer.push_back(0);
4523 }
4524 
4525 /// Helper to write the header common to all bitcode files.
4526 static void writeBitcodeHeader(BitstreamWriter &Stream) {
4527   // Emit the file header.
4528   Stream.Emit((unsigned)'B', 8);
4529   Stream.Emit((unsigned)'C', 8);
4530   Stream.Emit(0x0, 4);
4531   Stream.Emit(0xC, 4);
4532   Stream.Emit(0xE, 4);
4533   Stream.Emit(0xD, 4);
4534 }
4535 
4536 BitcodeWriter::BitcodeWriter(SmallVectorImpl<char> &Buffer, raw_fd_stream *FS)
4537     : Buffer(Buffer), Stream(new BitstreamWriter(Buffer, FS, FlushThreshold)) {
4538   writeBitcodeHeader(*Stream);
4539 }
4540 
4541 BitcodeWriter::~BitcodeWriter() { assert(WroteStrtab); }
4542 
4543 void BitcodeWriter::writeBlob(unsigned Block, unsigned Record, StringRef Blob) {
4544   Stream->EnterSubblock(Block, 3);
4545 
4546   auto Abbv = std::make_shared<BitCodeAbbrev>();
4547   Abbv->Add(BitCodeAbbrevOp(Record));
4548   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
4549   auto AbbrevNo = Stream->EmitAbbrev(std::move(Abbv));
4550 
4551   Stream->EmitRecordWithBlob(AbbrevNo, ArrayRef<uint64_t>{Record}, Blob);
4552 
4553   Stream->ExitBlock();
4554 }
4555 
4556 void BitcodeWriter::writeSymtab() {
4557   assert(!WroteStrtab && !WroteSymtab);
4558 
4559   // If any module has module-level inline asm, we will require a registered asm
4560   // parser for the target so that we can create an accurate symbol table for
4561   // the module.
4562   for (Module *M : Mods) {
4563     if (M->getModuleInlineAsm().empty())
4564       continue;
4565 
4566     std::string Err;
4567     const Triple TT(M->getTargetTriple());
4568     const Target *T = TargetRegistry::lookupTarget(TT.str(), Err);
4569     if (!T || !T->hasMCAsmParser())
4570       return;
4571   }
4572 
4573   WroteSymtab = true;
4574   SmallVector<char, 0> Symtab;
4575   // The irsymtab::build function may be unable to create a symbol table if the
4576   // module is malformed (e.g. it contains an invalid alias). Writing a symbol
4577   // table is not required for correctness, but we still want to be able to
4578   // write malformed modules to bitcode files, so swallow the error.
4579   if (Error E = irsymtab::build(Mods, Symtab, StrtabBuilder, Alloc)) {
4580     consumeError(std::move(E));
4581     return;
4582   }
4583 
4584   writeBlob(bitc::SYMTAB_BLOCK_ID, bitc::SYMTAB_BLOB,
4585             {Symtab.data(), Symtab.size()});
4586 }
4587 
4588 void BitcodeWriter::writeStrtab() {
4589   assert(!WroteStrtab);
4590 
4591   std::vector<char> Strtab;
4592   StrtabBuilder.finalizeInOrder();
4593   Strtab.resize(StrtabBuilder.getSize());
4594   StrtabBuilder.write((uint8_t *)Strtab.data());
4595 
4596   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB,
4597             {Strtab.data(), Strtab.size()});
4598 
4599   WroteStrtab = true;
4600 }
4601 
4602 void BitcodeWriter::copyStrtab(StringRef Strtab) {
4603   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB, Strtab);
4604   WroteStrtab = true;
4605 }
4606 
4607 void BitcodeWriter::writeModule(const Module &M,
4608                                 bool ShouldPreserveUseListOrder,
4609                                 const ModuleSummaryIndex *Index,
4610                                 bool GenerateHash, ModuleHash *ModHash) {
4611   assert(!WroteStrtab);
4612 
4613   // The Mods vector is used by irsymtab::build, which requires non-const
4614   // Modules in case it needs to materialize metadata. But the bitcode writer
4615   // requires that the module is materialized, so we can cast to non-const here,
4616   // after checking that it is in fact materialized.
4617   assert(M.isMaterialized());
4618   Mods.push_back(const_cast<Module *>(&M));
4619 
4620   ModuleBitcodeWriter ModuleWriter(M, Buffer, StrtabBuilder, *Stream,
4621                                    ShouldPreserveUseListOrder, Index,
4622                                    GenerateHash, ModHash);
4623   ModuleWriter.write();
4624 }
4625 
4626 void BitcodeWriter::writeIndex(
4627     const ModuleSummaryIndex *Index,
4628     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4629   IndexBitcodeWriter IndexWriter(*Stream, StrtabBuilder, *Index,
4630                                  ModuleToSummariesForIndex);
4631   IndexWriter.write();
4632 }
4633 
4634 /// Write the specified module to the specified output stream.
4635 void llvm::WriteBitcodeToFile(const Module &M, raw_ostream &Out,
4636                               bool ShouldPreserveUseListOrder,
4637                               const ModuleSummaryIndex *Index,
4638                               bool GenerateHash, ModuleHash *ModHash) {
4639   SmallVector<char, 0> Buffer;
4640   Buffer.reserve(256*1024);
4641 
4642   // If this is darwin or another generic macho target, reserve space for the
4643   // header.
4644   Triple TT(M.getTargetTriple());
4645   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4646     Buffer.insert(Buffer.begin(), BWH_HeaderSize, 0);
4647 
4648   BitcodeWriter Writer(Buffer, dyn_cast<raw_fd_stream>(&Out));
4649   Writer.writeModule(M, ShouldPreserveUseListOrder, Index, GenerateHash,
4650                      ModHash);
4651   Writer.writeSymtab();
4652   Writer.writeStrtab();
4653 
4654   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4655     emitDarwinBCHeaderAndTrailer(Buffer, TT);
4656 
4657   // Write the generated bitstream to "Out".
4658   if (!Buffer.empty())
4659     Out.write((char *)&Buffer.front(), Buffer.size());
4660 }
4661 
4662 void IndexBitcodeWriter::write() {
4663   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4664 
4665   writeModuleVersion();
4666 
4667   // Write the module paths in the combined index.
4668   writeModStrings();
4669 
4670   // Write the summary combined index records.
4671   writeCombinedGlobalValueSummary();
4672 
4673   Stream.ExitBlock();
4674 }
4675 
4676 // Write the specified module summary index to the given raw output stream,
4677 // where it will be written in a new bitcode block. This is used when
4678 // writing the combined index file for ThinLTO. When writing a subset of the
4679 // index for a distributed backend, provide a \p ModuleToSummariesForIndex map.
4680 void llvm::WriteIndexToFile(
4681     const ModuleSummaryIndex &Index, raw_ostream &Out,
4682     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4683   SmallVector<char, 0> Buffer;
4684   Buffer.reserve(256 * 1024);
4685 
4686   BitcodeWriter Writer(Buffer);
4687   Writer.writeIndex(&Index, ModuleToSummariesForIndex);
4688   Writer.writeStrtab();
4689 
4690   Out.write((char *)&Buffer.front(), Buffer.size());
4691 }
4692 
4693 namespace {
4694 
4695 /// Class to manage the bitcode writing for a thin link bitcode file.
4696 class ThinLinkBitcodeWriter : public ModuleBitcodeWriterBase {
4697   /// ModHash is for use in ThinLTO incremental build, generated while writing
4698   /// the module bitcode file.
4699   const ModuleHash *ModHash;
4700 
4701 public:
4702   ThinLinkBitcodeWriter(const Module &M, StringTableBuilder &StrtabBuilder,
4703                         BitstreamWriter &Stream,
4704                         const ModuleSummaryIndex &Index,
4705                         const ModuleHash &ModHash)
4706       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
4707                                 /*ShouldPreserveUseListOrder=*/false, &Index),
4708         ModHash(&ModHash) {}
4709 
4710   void write();
4711 
4712 private:
4713   void writeSimplifiedModuleInfo();
4714 };
4715 
4716 } // end anonymous namespace
4717 
4718 // This function writes a simpilified module info for thin link bitcode file.
4719 // It only contains the source file name along with the name(the offset and
4720 // size in strtab) and linkage for global values. For the global value info
4721 // entry, in order to keep linkage at offset 5, there are three zeros used
4722 // as padding.
4723 void ThinLinkBitcodeWriter::writeSimplifiedModuleInfo() {
4724   SmallVector<unsigned, 64> Vals;
4725   // Emit the module's source file name.
4726   {
4727     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
4728     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
4729     if (Bits == SE_Char6)
4730       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
4731     else if (Bits == SE_Fixed7)
4732       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
4733 
4734     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
4735     auto Abbv = std::make_shared<BitCodeAbbrev>();
4736     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
4737     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4738     Abbv->Add(AbbrevOpToUse);
4739     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4740 
4741     for (const auto P : M.getSourceFileName())
4742       Vals.push_back((unsigned char)P);
4743 
4744     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
4745     Vals.clear();
4746   }
4747 
4748   // Emit the global variable information.
4749   for (const GlobalVariable &GV : M.globals()) {
4750     // GLOBALVAR: [strtab offset, strtab size, 0, 0, 0, linkage]
4751     Vals.push_back(StrtabBuilder.add(GV.getName()));
4752     Vals.push_back(GV.getName().size());
4753     Vals.push_back(0);
4754     Vals.push_back(0);
4755     Vals.push_back(0);
4756     Vals.push_back(getEncodedLinkage(GV));
4757 
4758     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals);
4759     Vals.clear();
4760   }
4761 
4762   // Emit the function proto information.
4763   for (const Function &F : M) {
4764     // FUNCTION:  [strtab offset, strtab size, 0, 0, 0, linkage]
4765     Vals.push_back(StrtabBuilder.add(F.getName()));
4766     Vals.push_back(F.getName().size());
4767     Vals.push_back(0);
4768     Vals.push_back(0);
4769     Vals.push_back(0);
4770     Vals.push_back(getEncodedLinkage(F));
4771 
4772     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals);
4773     Vals.clear();
4774   }
4775 
4776   // Emit the alias information.
4777   for (const GlobalAlias &A : M.aliases()) {
4778     // ALIAS: [strtab offset, strtab size, 0, 0, 0, linkage]
4779     Vals.push_back(StrtabBuilder.add(A.getName()));
4780     Vals.push_back(A.getName().size());
4781     Vals.push_back(0);
4782     Vals.push_back(0);
4783     Vals.push_back(0);
4784     Vals.push_back(getEncodedLinkage(A));
4785 
4786     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals);
4787     Vals.clear();
4788   }
4789 
4790   // Emit the ifunc information.
4791   for (const GlobalIFunc &I : M.ifuncs()) {
4792     // IFUNC: [strtab offset, strtab size, 0, 0, 0, linkage]
4793     Vals.push_back(StrtabBuilder.add(I.getName()));
4794     Vals.push_back(I.getName().size());
4795     Vals.push_back(0);
4796     Vals.push_back(0);
4797     Vals.push_back(0);
4798     Vals.push_back(getEncodedLinkage(I));
4799 
4800     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
4801     Vals.clear();
4802   }
4803 }
4804 
4805 void ThinLinkBitcodeWriter::write() {
4806   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4807 
4808   writeModuleVersion();
4809 
4810   writeSimplifiedModuleInfo();
4811 
4812   writePerModuleGlobalValueSummary();
4813 
4814   // Write module hash.
4815   Stream.EmitRecord(bitc::MODULE_CODE_HASH, ArrayRef<uint32_t>(*ModHash));
4816 
4817   Stream.ExitBlock();
4818 }
4819 
4820 void BitcodeWriter::writeThinLinkBitcode(const Module &M,
4821                                          const ModuleSummaryIndex &Index,
4822                                          const ModuleHash &ModHash) {
4823   assert(!WroteStrtab);
4824 
4825   // The Mods vector is used by irsymtab::build, which requires non-const
4826   // Modules in case it needs to materialize metadata. But the bitcode writer
4827   // requires that the module is materialized, so we can cast to non-const here,
4828   // after checking that it is in fact materialized.
4829   assert(M.isMaterialized());
4830   Mods.push_back(const_cast<Module *>(&M));
4831 
4832   ThinLinkBitcodeWriter ThinLinkWriter(M, StrtabBuilder, *Stream, Index,
4833                                        ModHash);
4834   ThinLinkWriter.write();
4835 }
4836 
4837 // Write the specified thin link bitcode file to the given raw output stream,
4838 // where it will be written in a new bitcode block. This is used when
4839 // writing the per-module index file for ThinLTO.
4840 void llvm::WriteThinLinkBitcodeToFile(const Module &M, raw_ostream &Out,
4841                                       const ModuleSummaryIndex &Index,
4842                                       const ModuleHash &ModHash) {
4843   SmallVector<char, 0> Buffer;
4844   Buffer.reserve(256 * 1024);
4845 
4846   BitcodeWriter Writer(Buffer);
4847   Writer.writeThinLinkBitcode(M, Index, ModHash);
4848   Writer.writeSymtab();
4849   Writer.writeStrtab();
4850 
4851   Out.write((char *)&Buffer.front(), Buffer.size());
4852 }
4853 
4854 static const char *getSectionNameForBitcode(const Triple &T) {
4855   switch (T.getObjectFormat()) {
4856   case Triple::MachO:
4857     return "__LLVM,__bitcode";
4858   case Triple::COFF:
4859   case Triple::ELF:
4860   case Triple::Wasm:
4861   case Triple::UnknownObjectFormat:
4862     return ".llvmbc";
4863   case Triple::GOFF:
4864     llvm_unreachable("GOFF is not yet implemented");
4865     break;
4866   case Triple::XCOFF:
4867     llvm_unreachable("XCOFF is not yet implemented");
4868     break;
4869   }
4870   llvm_unreachable("Unimplemented ObjectFormatType");
4871 }
4872 
4873 static const char *getSectionNameForCommandline(const Triple &T) {
4874   switch (T.getObjectFormat()) {
4875   case Triple::MachO:
4876     return "__LLVM,__cmdline";
4877   case Triple::COFF:
4878   case Triple::ELF:
4879   case Triple::Wasm:
4880   case Triple::UnknownObjectFormat:
4881     return ".llvmcmd";
4882   case Triple::GOFF:
4883     llvm_unreachable("GOFF is not yet implemented");
4884     break;
4885   case Triple::XCOFF:
4886     llvm_unreachable("XCOFF is not yet implemented");
4887     break;
4888   }
4889   llvm_unreachable("Unimplemented ObjectFormatType");
4890 }
4891 
4892 void llvm::EmbedBitcodeInModule(llvm::Module &M, llvm::MemoryBufferRef Buf,
4893                                 bool EmbedBitcode, bool EmbedCmdline,
4894                                 const std::vector<uint8_t> &CmdArgs) {
4895   // Save llvm.compiler.used and remove it.
4896   SmallVector<Constant *, 2> UsedArray;
4897   SmallVector<GlobalValue *, 4> UsedGlobals;
4898   Type *UsedElementType = Type::getInt8Ty(M.getContext())->getPointerTo(0);
4899   GlobalVariable *Used = collectUsedGlobalVariables(M, UsedGlobals, true);
4900   for (auto *GV : UsedGlobals) {
4901     if (GV->getName() != "llvm.embedded.module" &&
4902         GV->getName() != "llvm.cmdline")
4903       UsedArray.push_back(
4904           ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
4905   }
4906   if (Used)
4907     Used->eraseFromParent();
4908 
4909   // Embed the bitcode for the llvm module.
4910   std::string Data;
4911   ArrayRef<uint8_t> ModuleData;
4912   Triple T(M.getTargetTriple());
4913 
4914   if (EmbedBitcode) {
4915     if (Buf.getBufferSize() == 0 ||
4916         !isBitcode((const unsigned char *)Buf.getBufferStart(),
4917                    (const unsigned char *)Buf.getBufferEnd())) {
4918       // If the input is LLVM Assembly, bitcode is produced by serializing
4919       // the module. Use-lists order need to be preserved in this case.
4920       llvm::raw_string_ostream OS(Data);
4921       llvm::WriteBitcodeToFile(M, OS, /* ShouldPreserveUseListOrder */ true);
4922       ModuleData =
4923           ArrayRef<uint8_t>((const uint8_t *)OS.str().data(), OS.str().size());
4924     } else
4925       // If the input is LLVM bitcode, write the input byte stream directly.
4926       ModuleData = ArrayRef<uint8_t>((const uint8_t *)Buf.getBufferStart(),
4927                                      Buf.getBufferSize());
4928   }
4929   llvm::Constant *ModuleConstant =
4930       llvm::ConstantDataArray::get(M.getContext(), ModuleData);
4931   llvm::GlobalVariable *GV = new llvm::GlobalVariable(
4932       M, ModuleConstant->getType(), true, llvm::GlobalValue::PrivateLinkage,
4933       ModuleConstant);
4934   GV->setSection(getSectionNameForBitcode(T));
4935   // Set alignment to 1 to prevent padding between two contributions from input
4936   // sections after linking.
4937   GV->setAlignment(Align(1));
4938   UsedArray.push_back(
4939       ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
4940   if (llvm::GlobalVariable *Old =
4941           M.getGlobalVariable("llvm.embedded.module", true)) {
4942     assert(Old->hasOneUse() &&
4943            "llvm.embedded.module can only be used once in llvm.compiler.used");
4944     GV->takeName(Old);
4945     Old->eraseFromParent();
4946   } else {
4947     GV->setName("llvm.embedded.module");
4948   }
4949 
4950   // Skip if only bitcode needs to be embedded.
4951   if (EmbedCmdline) {
4952     // Embed command-line options.
4953     ArrayRef<uint8_t> CmdData(const_cast<uint8_t *>(CmdArgs.data()),
4954                               CmdArgs.size());
4955     llvm::Constant *CmdConstant =
4956         llvm::ConstantDataArray::get(M.getContext(), CmdData);
4957     GV = new llvm::GlobalVariable(M, CmdConstant->getType(), true,
4958                                   llvm::GlobalValue::PrivateLinkage,
4959                                   CmdConstant);
4960     GV->setSection(getSectionNameForCommandline(T));
4961     GV->setAlignment(Align(1));
4962     UsedArray.push_back(
4963         ConstantExpr::getPointerBitCastOrAddrSpaceCast(GV, UsedElementType));
4964     if (llvm::GlobalVariable *Old = M.getGlobalVariable("llvm.cmdline", true)) {
4965       assert(Old->hasOneUse() &&
4966              "llvm.cmdline can only be used once in llvm.compiler.used");
4967       GV->takeName(Old);
4968       Old->eraseFromParent();
4969     } else {
4970       GV->setName("llvm.cmdline");
4971     }
4972   }
4973 
4974   if (UsedArray.empty())
4975     return;
4976 
4977   // Recreate llvm.compiler.used.
4978   ArrayType *ATy = ArrayType::get(UsedElementType, UsedArray.size());
4979   auto *NewUsed = new GlobalVariable(
4980       M, ATy, false, llvm::GlobalValue::AppendingLinkage,
4981       llvm::ConstantArray::get(ATy, UsedArray), "llvm.compiler.used");
4982   NewUsed->setSection("llvm.metadata");
4983 }
4984