xref: /llvm-project/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp (revision 957c40db6aebcbcdc4c80614649f917d93b73b4f)
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/Bitstream/BitCodes.h"
28 #include "llvm/Bitstream/BitstreamWriter.h"
29 #include "llvm/Bitcode/LLVMBitCodes.h"
30 #include "llvm/Config/llvm-config.h"
31 #include "llvm/IR/Attributes.h"
32 #include "llvm/IR/BasicBlock.h"
33 #include "llvm/IR/CallSite.h"
34 #include "llvm/IR/Comdat.h"
35 #include "llvm/IR/Constant.h"
36 #include "llvm/IR/Constants.h"
37 #include "llvm/IR/DebugInfoMetadata.h"
38 #include "llvm/IR/DebugLoc.h"
39 #include "llvm/IR/DerivedTypes.h"
40 #include "llvm/IR/Function.h"
41 #include "llvm/IR/GlobalAlias.h"
42 #include "llvm/IR/GlobalIFunc.h"
43 #include "llvm/IR/GlobalObject.h"
44 #include "llvm/IR/GlobalValue.h"
45 #include "llvm/IR/GlobalVariable.h"
46 #include "llvm/IR/InlineAsm.h"
47 #include "llvm/IR/InstrTypes.h"
48 #include "llvm/IR/Instruction.h"
49 #include "llvm/IR/Instructions.h"
50 #include "llvm/IR/LLVMContext.h"
51 #include "llvm/IR/Metadata.h"
52 #include "llvm/IR/Module.h"
53 #include "llvm/IR/ModuleSummaryIndex.h"
54 #include "llvm/IR/Operator.h"
55 #include "llvm/IR/Type.h"
56 #include "llvm/IR/UseListOrder.h"
57 #include "llvm/IR/Value.h"
58 #include "llvm/IR/ValueSymbolTable.h"
59 #include "llvm/MC/StringTableBuilder.h"
60 #include "llvm/Object/IRSymtab.h"
61 #include "llvm/Support/AtomicOrdering.h"
62 #include "llvm/Support/Casting.h"
63 #include "llvm/Support/CommandLine.h"
64 #include "llvm/Support/Endian.h"
65 #include "llvm/Support/Error.h"
66 #include "llvm/Support/ErrorHandling.h"
67 #include "llvm/Support/MathExtras.h"
68 #include "llvm/Support/SHA1.h"
69 #include "llvm/Support/TargetRegistry.h"
70 #include "llvm/Support/raw_ostream.h"
71 #include <algorithm>
72 #include <cassert>
73 #include <cstddef>
74 #include <cstdint>
75 #include <iterator>
76 #include <map>
77 #include <memory>
78 #include <string>
79 #include <utility>
80 #include <vector>
81 
82 using namespace llvm;
83 
84 static cl::opt<unsigned>
85     IndexThreshold("bitcode-mdindex-threshold", cl::Hidden, cl::init(25),
86                    cl::desc("Number of metadatas above which we emit an index "
87                             "to enable lazy-loading"));
88 
89 cl::opt<bool> WriteRelBFToSummary(
90     "write-relbf-to-summary", cl::Hidden, cl::init(false),
91     cl::desc("Write relative block frequency to function summary "));
92 
93 extern FunctionSummary::ForceSummaryHotnessType ForceSummaryEdgesCold;
94 
95 namespace {
96 
97 /// These are manifest constants used by the bitcode writer. They do not need to
98 /// be kept in sync with the reader, but need to be consistent within this file.
99 enum {
100   // VALUE_SYMTAB_BLOCK abbrev id's.
101   VST_ENTRY_8_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
102   VST_ENTRY_7_ABBREV,
103   VST_ENTRY_6_ABBREV,
104   VST_BBENTRY_6_ABBREV,
105 
106   // CONSTANTS_BLOCK abbrev id's.
107   CONSTANTS_SETTYPE_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
108   CONSTANTS_INTEGER_ABBREV,
109   CONSTANTS_CE_CAST_Abbrev,
110   CONSTANTS_NULL_Abbrev,
111 
112   // FUNCTION_BLOCK abbrev id's.
113   FUNCTION_INST_LOAD_ABBREV = bitc::FIRST_APPLICATION_ABBREV,
114   FUNCTION_INST_UNOP_ABBREV,
115   FUNCTION_INST_UNOP_FLAGS_ABBREV,
116   FUNCTION_INST_BINOP_ABBREV,
117   FUNCTION_INST_BINOP_FLAGS_ABBREV,
118   FUNCTION_INST_CAST_ABBREV,
119   FUNCTION_INST_RET_VOID_ABBREV,
120   FUNCTION_INST_RET_VAL_ABBREV,
121   FUNCTION_INST_UNREACHABLE_ABBREV,
122   FUNCTION_INST_GEP_ABBREV,
123 };
124 
125 /// Abstract class to manage the bitcode writing, subclassed for each bitcode
126 /// file type.
127 class BitcodeWriterBase {
128 protected:
129   /// The stream created and owned by the client.
130   BitstreamWriter &Stream;
131 
132   StringTableBuilder &StrtabBuilder;
133 
134 public:
135   /// Constructs a BitcodeWriterBase object that writes to the provided
136   /// \p Stream.
137   BitcodeWriterBase(BitstreamWriter &Stream, StringTableBuilder &StrtabBuilder)
138       : Stream(Stream), StrtabBuilder(StrtabBuilder) {}
139 
140 protected:
141   void writeBitcodeHeader();
142   void writeModuleVersion();
143 };
144 
145 void BitcodeWriterBase::writeModuleVersion() {
146   // VERSION: [version#]
147   Stream.EmitRecord(bitc::MODULE_CODE_VERSION, ArrayRef<uint64_t>{2});
148 }
149 
150 /// Base class to manage the module bitcode writing, currently subclassed for
151 /// ModuleBitcodeWriter and ThinLinkBitcodeWriter.
152 class ModuleBitcodeWriterBase : public BitcodeWriterBase {
153 protected:
154   /// The Module to write to bitcode.
155   const Module &M;
156 
157   /// Enumerates ids for all values in the module.
158   ValueEnumerator VE;
159 
160   /// Optional per-module index to write for ThinLTO.
161   const ModuleSummaryIndex *Index;
162 
163   /// Map that holds the correspondence between GUIDs in the summary index,
164   /// that came from indirect call profiles, and a value id generated by this
165   /// class to use in the VST and summary block records.
166   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
167 
168   /// Tracks the last value id recorded in the GUIDToValueMap.
169   unsigned GlobalValueId;
170 
171   /// Saves the offset of the VSTOffset record that must eventually be
172   /// backpatched with the offset of the actual VST.
173   uint64_t VSTOffsetPlaceholder = 0;
174 
175 public:
176   /// Constructs a ModuleBitcodeWriterBase object for the given Module,
177   /// writing to the provided \p Buffer.
178   ModuleBitcodeWriterBase(const Module &M, StringTableBuilder &StrtabBuilder,
179                           BitstreamWriter &Stream,
180                           bool ShouldPreserveUseListOrder,
181                           const ModuleSummaryIndex *Index)
182       : BitcodeWriterBase(Stream, StrtabBuilder), M(M),
183         VE(M, ShouldPreserveUseListOrder), Index(Index) {
184     // Assign ValueIds to any callee values in the index that came from
185     // indirect call profiles and were recorded as a GUID not a Value*
186     // (which would have been assigned an ID by the ValueEnumerator).
187     // The starting ValueId is just after the number of values in the
188     // ValueEnumerator, so that they can be emitted in the VST.
189     GlobalValueId = VE.getValues().size();
190     if (!Index)
191       return;
192     for (const auto &GUIDSummaryLists : *Index)
193       // Examine all summaries for this GUID.
194       for (auto &Summary : GUIDSummaryLists.second.SummaryList)
195         if (auto FS = dyn_cast<FunctionSummary>(Summary.get()))
196           // For each call in the function summary, see if the call
197           // is to a GUID (which means it is for an indirect call,
198           // otherwise we would have a Value for it). If so, synthesize
199           // a value id.
200           for (auto &CallEdge : FS->calls())
201             if (!CallEdge.first.haveGVs() || !CallEdge.first.getValue())
202               assignValueId(CallEdge.first.getGUID());
203   }
204 
205 protected:
206   void writePerModuleGlobalValueSummary();
207 
208 private:
209   void writePerModuleFunctionSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
210                                            GlobalValueSummary *Summary,
211                                            unsigned ValueID,
212                                            unsigned FSCallsAbbrev,
213                                            unsigned FSCallsProfileAbbrev,
214                                            const Function &F);
215   void writeModuleLevelReferences(const GlobalVariable &V,
216                                   SmallVector<uint64_t, 64> &NameVals,
217                                   unsigned FSModRefsAbbrev,
218                                   unsigned FSModVTableRefsAbbrev);
219 
220   void assignValueId(GlobalValue::GUID ValGUID) {
221     GUIDToValueIdMap[ValGUID] = ++GlobalValueId;
222   }
223 
224   unsigned getValueId(GlobalValue::GUID ValGUID) {
225     const auto &VMI = GUIDToValueIdMap.find(ValGUID);
226     // Expect that any GUID value had a value Id assigned by an
227     // earlier call to assignValueId.
228     assert(VMI != GUIDToValueIdMap.end() &&
229            "GUID does not have assigned value Id");
230     return VMI->second;
231   }
232 
233   // Helper to get the valueId for the type of value recorded in VI.
234   unsigned getValueId(ValueInfo VI) {
235     if (!VI.haveGVs() || !VI.getValue())
236       return getValueId(VI.getGUID());
237     return VE.getValueID(VI.getValue());
238   }
239 
240   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
241 };
242 
243 /// Class to manage the bitcode writing for a module.
244 class ModuleBitcodeWriter : public ModuleBitcodeWriterBase {
245   /// Pointer to the buffer allocated by caller for bitcode writing.
246   const SmallVectorImpl<char> &Buffer;
247 
248   /// True if a module hash record should be written.
249   bool GenerateHash;
250 
251   /// If non-null, when GenerateHash is true, the resulting hash is written
252   /// into ModHash.
253   ModuleHash *ModHash;
254 
255   SHA1 Hasher;
256 
257   /// The start bit of the identification block.
258   uint64_t BitcodeStartBit;
259 
260 public:
261   /// Constructs a ModuleBitcodeWriter object for the given Module,
262   /// writing to the provided \p Buffer.
263   ModuleBitcodeWriter(const Module &M, SmallVectorImpl<char> &Buffer,
264                       StringTableBuilder &StrtabBuilder,
265                       BitstreamWriter &Stream, bool ShouldPreserveUseListOrder,
266                       const ModuleSummaryIndex *Index, bool GenerateHash,
267                       ModuleHash *ModHash = nullptr)
268       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
269                                 ShouldPreserveUseListOrder, Index),
270         Buffer(Buffer), GenerateHash(GenerateHash), ModHash(ModHash),
271         BitcodeStartBit(Stream.GetCurrentBitNo()) {}
272 
273   /// Emit the current module to the bitstream.
274   void write();
275 
276 private:
277   uint64_t bitcodeStartBit() { return BitcodeStartBit; }
278 
279   size_t addToStrtab(StringRef Str);
280 
281   void writeAttributeGroupTable();
282   void writeAttributeTable();
283   void writeTypeTable();
284   void writeComdats();
285   void writeValueSymbolTableForwardDecl();
286   void writeModuleInfo();
287   void writeValueAsMetadata(const ValueAsMetadata *MD,
288                             SmallVectorImpl<uint64_t> &Record);
289   void writeMDTuple(const MDTuple *N, SmallVectorImpl<uint64_t> &Record,
290                     unsigned Abbrev);
291   unsigned createDILocationAbbrev();
292   void writeDILocation(const DILocation *N, SmallVectorImpl<uint64_t> &Record,
293                        unsigned &Abbrev);
294   unsigned createGenericDINodeAbbrev();
295   void writeGenericDINode(const GenericDINode *N,
296                           SmallVectorImpl<uint64_t> &Record, unsigned &Abbrev);
297   void writeDISubrange(const DISubrange *N, SmallVectorImpl<uint64_t> &Record,
298                        unsigned Abbrev);
299   void writeDIEnumerator(const DIEnumerator *N,
300                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
301   void writeDIBasicType(const DIBasicType *N, SmallVectorImpl<uint64_t> &Record,
302                         unsigned Abbrev);
303   void writeDIDerivedType(const DIDerivedType *N,
304                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
305   void writeDICompositeType(const DICompositeType *N,
306                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
307   void writeDISubroutineType(const DISubroutineType *N,
308                              SmallVectorImpl<uint64_t> &Record,
309                              unsigned Abbrev);
310   void writeDIFile(const DIFile *N, SmallVectorImpl<uint64_t> &Record,
311                    unsigned Abbrev);
312   void writeDICompileUnit(const DICompileUnit *N,
313                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
314   void writeDISubprogram(const DISubprogram *N,
315                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
316   void writeDILexicalBlock(const DILexicalBlock *N,
317                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
318   void writeDILexicalBlockFile(const DILexicalBlockFile *N,
319                                SmallVectorImpl<uint64_t> &Record,
320                                unsigned Abbrev);
321   void writeDICommonBlock(const DICommonBlock *N,
322                           SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
323   void writeDINamespace(const DINamespace *N, SmallVectorImpl<uint64_t> &Record,
324                         unsigned Abbrev);
325   void writeDIMacro(const DIMacro *N, SmallVectorImpl<uint64_t> &Record,
326                     unsigned Abbrev);
327   void writeDIMacroFile(const DIMacroFile *N, SmallVectorImpl<uint64_t> &Record,
328                         unsigned Abbrev);
329   void writeDIModule(const DIModule *N, SmallVectorImpl<uint64_t> &Record,
330                      unsigned Abbrev);
331   void writeDITemplateTypeParameter(const DITemplateTypeParameter *N,
332                                     SmallVectorImpl<uint64_t> &Record,
333                                     unsigned Abbrev);
334   void writeDITemplateValueParameter(const DITemplateValueParameter *N,
335                                      SmallVectorImpl<uint64_t> &Record,
336                                      unsigned Abbrev);
337   void writeDIGlobalVariable(const DIGlobalVariable *N,
338                              SmallVectorImpl<uint64_t> &Record,
339                              unsigned Abbrev);
340   void writeDILocalVariable(const DILocalVariable *N,
341                             SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
342   void writeDILabel(const DILabel *N,
343                     SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
344   void writeDIExpression(const DIExpression *N,
345                          SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
346   void writeDIGlobalVariableExpression(const DIGlobalVariableExpression *N,
347                                        SmallVectorImpl<uint64_t> &Record,
348                                        unsigned Abbrev);
349   void writeDIObjCProperty(const DIObjCProperty *N,
350                            SmallVectorImpl<uint64_t> &Record, unsigned Abbrev);
351   void writeDIImportedEntity(const DIImportedEntity *N,
352                              SmallVectorImpl<uint64_t> &Record,
353                              unsigned Abbrev);
354   unsigned createNamedMetadataAbbrev();
355   void writeNamedMetadata(SmallVectorImpl<uint64_t> &Record);
356   unsigned createMetadataStringsAbbrev();
357   void writeMetadataStrings(ArrayRef<const Metadata *> Strings,
358                             SmallVectorImpl<uint64_t> &Record);
359   void writeMetadataRecords(ArrayRef<const Metadata *> MDs,
360                             SmallVectorImpl<uint64_t> &Record,
361                             std::vector<unsigned> *MDAbbrevs = nullptr,
362                             std::vector<uint64_t> *IndexPos = nullptr);
363   void writeModuleMetadata();
364   void writeFunctionMetadata(const Function &F);
365   void writeFunctionMetadataAttachment(const Function &F);
366   void writeGlobalVariableMetadataAttachment(const GlobalVariable &GV);
367   void pushGlobalMetadataAttachment(SmallVectorImpl<uint64_t> &Record,
368                                     const GlobalObject &GO);
369   void writeModuleMetadataKinds();
370   void writeOperandBundleTags();
371   void writeSyncScopeNames();
372   void writeConstants(unsigned FirstVal, unsigned LastVal, bool isGlobal);
373   void writeModuleConstants();
374   bool pushValueAndType(const Value *V, unsigned InstID,
375                         SmallVectorImpl<unsigned> &Vals);
376   void writeOperandBundles(ImmutableCallSite CS, unsigned InstID);
377   void pushValue(const Value *V, unsigned InstID,
378                  SmallVectorImpl<unsigned> &Vals);
379   void pushValueSigned(const Value *V, unsigned InstID,
380                        SmallVectorImpl<uint64_t> &Vals);
381   void writeInstruction(const Instruction &I, unsigned InstID,
382                         SmallVectorImpl<unsigned> &Vals);
383   void writeFunctionLevelValueSymbolTable(const ValueSymbolTable &VST);
384   void writeGlobalValueSymbolTable(
385       DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
386   void writeUseList(UseListOrder &&Order);
387   void writeUseListBlock(const Function *F);
388   void
389   writeFunction(const Function &F,
390                 DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex);
391   void writeBlockInfo();
392   void writeModuleHash(size_t BlockStartPos);
393 
394   unsigned getEncodedSyncScopeID(SyncScope::ID SSID) {
395     return unsigned(SSID);
396   }
397 };
398 
399 /// Class to manage the bitcode writing for a combined index.
400 class IndexBitcodeWriter : public BitcodeWriterBase {
401   /// The combined index to write to bitcode.
402   const ModuleSummaryIndex &Index;
403 
404   /// When writing a subset of the index for distributed backends, client
405   /// provides a map of modules to the corresponding GUIDs/summaries to write.
406   const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex;
407 
408   /// Map that holds the correspondence between the GUID used in the combined
409   /// index and a value id generated by this class to use in references.
410   std::map<GlobalValue::GUID, unsigned> GUIDToValueIdMap;
411 
412   /// Tracks the last value id recorded in the GUIDToValueMap.
413   unsigned GlobalValueId = 0;
414 
415 public:
416   /// Constructs a IndexBitcodeWriter object for the given combined index,
417   /// writing to the provided \p Buffer. When writing a subset of the index
418   /// for a distributed backend, provide a \p ModuleToSummariesForIndex map.
419   IndexBitcodeWriter(BitstreamWriter &Stream, StringTableBuilder &StrtabBuilder,
420                      const ModuleSummaryIndex &Index,
421                      const std::map<std::string, GVSummaryMapTy>
422                          *ModuleToSummariesForIndex = nullptr)
423       : BitcodeWriterBase(Stream, StrtabBuilder), Index(Index),
424         ModuleToSummariesForIndex(ModuleToSummariesForIndex) {
425     // Assign unique value ids to all summaries to be written, for use
426     // in writing out the call graph edges. Save the mapping from GUID
427     // to the new global value id to use when writing those edges, which
428     // are currently saved in the index in terms of GUID.
429     forEachSummary([&](GVInfo I, bool) {
430       GUIDToValueIdMap[I.first] = ++GlobalValueId;
431     });
432   }
433 
434   /// The below iterator returns the GUID and associated summary.
435   using GVInfo = std::pair<GlobalValue::GUID, GlobalValueSummary *>;
436 
437   /// Calls the callback for each value GUID and summary to be written to
438   /// bitcode. This hides the details of whether they are being pulled from the
439   /// entire index or just those in a provided ModuleToSummariesForIndex map.
440   template<typename Functor>
441   void forEachSummary(Functor Callback) {
442     if (ModuleToSummariesForIndex) {
443       for (auto &M : *ModuleToSummariesForIndex)
444         for (auto &Summary : M.second) {
445           Callback(Summary, false);
446           // Ensure aliasee is handled, e.g. for assigning a valueId,
447           // even if we are not importing the aliasee directly (the
448           // imported alias will contain a copy of aliasee).
449           if (auto *AS = dyn_cast<AliasSummary>(Summary.getSecond()))
450             Callback({AS->getAliaseeGUID(), &AS->getAliasee()}, true);
451         }
452     } else {
453       for (auto &Summaries : Index)
454         for (auto &Summary : Summaries.second.SummaryList)
455           Callback({Summaries.first, Summary.get()}, false);
456     }
457   }
458 
459   /// Calls the callback for each entry in the modulePaths StringMap that
460   /// should be written to the module path string table. This hides the details
461   /// of whether they are being pulled from the entire index or just those in a
462   /// provided ModuleToSummariesForIndex map.
463   template <typename Functor> void forEachModule(Functor Callback) {
464     if (ModuleToSummariesForIndex) {
465       for (const auto &M : *ModuleToSummariesForIndex) {
466         const auto &MPI = Index.modulePaths().find(M.first);
467         if (MPI == Index.modulePaths().end()) {
468           // This should only happen if the bitcode file was empty, in which
469           // case we shouldn't be importing (the ModuleToSummariesForIndex
470           // would only include the module we are writing and index for).
471           assert(ModuleToSummariesForIndex->size() == 1);
472           continue;
473         }
474         Callback(*MPI);
475       }
476     } else {
477       for (const auto &MPSE : Index.modulePaths())
478         Callback(MPSE);
479     }
480   }
481 
482   /// Main entry point for writing a combined index to bitcode.
483   void write();
484 
485 private:
486   void writeModStrings();
487   void writeCombinedGlobalValueSummary();
488 
489   Optional<unsigned> getValueId(GlobalValue::GUID ValGUID) {
490     auto VMI = GUIDToValueIdMap.find(ValGUID);
491     if (VMI == GUIDToValueIdMap.end())
492       return None;
493     return VMI->second;
494   }
495 
496   std::map<GlobalValue::GUID, unsigned> &valueIds() { return GUIDToValueIdMap; }
497 };
498 
499 } // end anonymous namespace
500 
501 static unsigned getEncodedCastOpcode(unsigned Opcode) {
502   switch (Opcode) {
503   default: llvm_unreachable("Unknown cast instruction!");
504   case Instruction::Trunc   : return bitc::CAST_TRUNC;
505   case Instruction::ZExt    : return bitc::CAST_ZEXT;
506   case Instruction::SExt    : return bitc::CAST_SEXT;
507   case Instruction::FPToUI  : return bitc::CAST_FPTOUI;
508   case Instruction::FPToSI  : return bitc::CAST_FPTOSI;
509   case Instruction::UIToFP  : return bitc::CAST_UITOFP;
510   case Instruction::SIToFP  : return bitc::CAST_SITOFP;
511   case Instruction::FPTrunc : return bitc::CAST_FPTRUNC;
512   case Instruction::FPExt   : return bitc::CAST_FPEXT;
513   case Instruction::PtrToInt: return bitc::CAST_PTRTOINT;
514   case Instruction::IntToPtr: return bitc::CAST_INTTOPTR;
515   case Instruction::BitCast : return bitc::CAST_BITCAST;
516   case Instruction::AddrSpaceCast: return bitc::CAST_ADDRSPACECAST;
517   }
518 }
519 
520 static unsigned getEncodedUnaryOpcode(unsigned Opcode) {
521   switch (Opcode) {
522   default: llvm_unreachable("Unknown binary instruction!");
523   case Instruction::FNeg: return bitc::UNOP_NEG;
524   }
525 }
526 
527 static unsigned getEncodedBinaryOpcode(unsigned Opcode) {
528   switch (Opcode) {
529   default: llvm_unreachable("Unknown binary instruction!");
530   case Instruction::Add:
531   case Instruction::FAdd: return bitc::BINOP_ADD;
532   case Instruction::Sub:
533   case Instruction::FSub: return bitc::BINOP_SUB;
534   case Instruction::Mul:
535   case Instruction::FMul: return bitc::BINOP_MUL;
536   case Instruction::UDiv: return bitc::BINOP_UDIV;
537   case Instruction::FDiv:
538   case Instruction::SDiv: return bitc::BINOP_SDIV;
539   case Instruction::URem: return bitc::BINOP_UREM;
540   case Instruction::FRem:
541   case Instruction::SRem: return bitc::BINOP_SREM;
542   case Instruction::Shl:  return bitc::BINOP_SHL;
543   case Instruction::LShr: return bitc::BINOP_LSHR;
544   case Instruction::AShr: return bitc::BINOP_ASHR;
545   case Instruction::And:  return bitc::BINOP_AND;
546   case Instruction::Or:   return bitc::BINOP_OR;
547   case Instruction::Xor:  return bitc::BINOP_XOR;
548   }
549 }
550 
551 static unsigned getEncodedRMWOperation(AtomicRMWInst::BinOp Op) {
552   switch (Op) {
553   default: llvm_unreachable("Unknown RMW operation!");
554   case AtomicRMWInst::Xchg: return bitc::RMW_XCHG;
555   case AtomicRMWInst::Add: return bitc::RMW_ADD;
556   case AtomicRMWInst::Sub: return bitc::RMW_SUB;
557   case AtomicRMWInst::And: return bitc::RMW_AND;
558   case AtomicRMWInst::Nand: return bitc::RMW_NAND;
559   case AtomicRMWInst::Or: return bitc::RMW_OR;
560   case AtomicRMWInst::Xor: return bitc::RMW_XOR;
561   case AtomicRMWInst::Max: return bitc::RMW_MAX;
562   case AtomicRMWInst::Min: return bitc::RMW_MIN;
563   case AtomicRMWInst::UMax: return bitc::RMW_UMAX;
564   case AtomicRMWInst::UMin: return bitc::RMW_UMIN;
565   case AtomicRMWInst::FAdd: return bitc::RMW_FADD;
566   case AtomicRMWInst::FSub: return bitc::RMW_FSUB;
567   }
568 }
569 
570 static unsigned getEncodedOrdering(AtomicOrdering Ordering) {
571   switch (Ordering) {
572   case AtomicOrdering::NotAtomic: return bitc::ORDERING_NOTATOMIC;
573   case AtomicOrdering::Unordered: return bitc::ORDERING_UNORDERED;
574   case AtomicOrdering::Monotonic: return bitc::ORDERING_MONOTONIC;
575   case AtomicOrdering::Acquire: return bitc::ORDERING_ACQUIRE;
576   case AtomicOrdering::Release: return bitc::ORDERING_RELEASE;
577   case AtomicOrdering::AcquireRelease: return bitc::ORDERING_ACQREL;
578   case AtomicOrdering::SequentiallyConsistent: return bitc::ORDERING_SEQCST;
579   }
580   llvm_unreachable("Invalid ordering");
581 }
582 
583 static void writeStringRecord(BitstreamWriter &Stream, unsigned Code,
584                               StringRef Str, unsigned AbbrevToUse) {
585   SmallVector<unsigned, 64> Vals;
586 
587   // Code: [strchar x N]
588   for (unsigned i = 0, e = Str.size(); i != e; ++i) {
589     if (AbbrevToUse && !BitCodeAbbrevOp::isChar6(Str[i]))
590       AbbrevToUse = 0;
591     Vals.push_back(Str[i]);
592   }
593 
594   // Emit the finished record.
595   Stream.EmitRecord(Code, Vals, AbbrevToUse);
596 }
597 
598 static uint64_t getAttrKindEncoding(Attribute::AttrKind Kind) {
599   switch (Kind) {
600   case Attribute::Alignment:
601     return bitc::ATTR_KIND_ALIGNMENT;
602   case Attribute::AllocSize:
603     return bitc::ATTR_KIND_ALLOC_SIZE;
604   case Attribute::AlwaysInline:
605     return bitc::ATTR_KIND_ALWAYS_INLINE;
606   case Attribute::ArgMemOnly:
607     return bitc::ATTR_KIND_ARGMEMONLY;
608   case Attribute::Builtin:
609     return bitc::ATTR_KIND_BUILTIN;
610   case Attribute::ByVal:
611     return bitc::ATTR_KIND_BY_VAL;
612   case Attribute::Convergent:
613     return bitc::ATTR_KIND_CONVERGENT;
614   case Attribute::InAlloca:
615     return bitc::ATTR_KIND_IN_ALLOCA;
616   case Attribute::Cold:
617     return bitc::ATTR_KIND_COLD;
618   case Attribute::InaccessibleMemOnly:
619     return bitc::ATTR_KIND_INACCESSIBLEMEM_ONLY;
620   case Attribute::InaccessibleMemOrArgMemOnly:
621     return bitc::ATTR_KIND_INACCESSIBLEMEM_OR_ARGMEMONLY;
622   case Attribute::InlineHint:
623     return bitc::ATTR_KIND_INLINE_HINT;
624   case Attribute::InReg:
625     return bitc::ATTR_KIND_IN_REG;
626   case Attribute::JumpTable:
627     return bitc::ATTR_KIND_JUMP_TABLE;
628   case Attribute::MinSize:
629     return bitc::ATTR_KIND_MIN_SIZE;
630   case Attribute::Naked:
631     return bitc::ATTR_KIND_NAKED;
632   case Attribute::Nest:
633     return bitc::ATTR_KIND_NEST;
634   case Attribute::NoAlias:
635     return bitc::ATTR_KIND_NO_ALIAS;
636   case Attribute::NoBuiltin:
637     return bitc::ATTR_KIND_NO_BUILTIN;
638   case Attribute::NoCapture:
639     return bitc::ATTR_KIND_NO_CAPTURE;
640   case Attribute::NoDuplicate:
641     return bitc::ATTR_KIND_NO_DUPLICATE;
642   case Attribute::NoImplicitFloat:
643     return bitc::ATTR_KIND_NO_IMPLICIT_FLOAT;
644   case Attribute::NoInline:
645     return bitc::ATTR_KIND_NO_INLINE;
646   case Attribute::NoRecurse:
647     return bitc::ATTR_KIND_NO_RECURSE;
648   case Attribute::NonLazyBind:
649     return bitc::ATTR_KIND_NON_LAZY_BIND;
650   case Attribute::NonNull:
651     return bitc::ATTR_KIND_NON_NULL;
652   case Attribute::Dereferenceable:
653     return bitc::ATTR_KIND_DEREFERENCEABLE;
654   case Attribute::DereferenceableOrNull:
655     return bitc::ATTR_KIND_DEREFERENCEABLE_OR_NULL;
656   case Attribute::NoRedZone:
657     return bitc::ATTR_KIND_NO_RED_ZONE;
658   case Attribute::NoReturn:
659     return bitc::ATTR_KIND_NO_RETURN;
660   case Attribute::NoCfCheck:
661     return bitc::ATTR_KIND_NOCF_CHECK;
662   case Attribute::NoUnwind:
663     return bitc::ATTR_KIND_NO_UNWIND;
664   case Attribute::OptForFuzzing:
665     return bitc::ATTR_KIND_OPT_FOR_FUZZING;
666   case Attribute::OptimizeForSize:
667     return bitc::ATTR_KIND_OPTIMIZE_FOR_SIZE;
668   case Attribute::OptimizeNone:
669     return bitc::ATTR_KIND_OPTIMIZE_NONE;
670   case Attribute::ReadNone:
671     return bitc::ATTR_KIND_READ_NONE;
672   case Attribute::ReadOnly:
673     return bitc::ATTR_KIND_READ_ONLY;
674   case Attribute::Returned:
675     return bitc::ATTR_KIND_RETURNED;
676   case Attribute::ReturnsTwice:
677     return bitc::ATTR_KIND_RETURNS_TWICE;
678   case Attribute::SExt:
679     return bitc::ATTR_KIND_S_EXT;
680   case Attribute::Speculatable:
681     return bitc::ATTR_KIND_SPECULATABLE;
682   case Attribute::StackAlignment:
683     return bitc::ATTR_KIND_STACK_ALIGNMENT;
684   case Attribute::StackProtect:
685     return bitc::ATTR_KIND_STACK_PROTECT;
686   case Attribute::StackProtectReq:
687     return bitc::ATTR_KIND_STACK_PROTECT_REQ;
688   case Attribute::StackProtectStrong:
689     return bitc::ATTR_KIND_STACK_PROTECT_STRONG;
690   case Attribute::SafeStack:
691     return bitc::ATTR_KIND_SAFESTACK;
692   case Attribute::ShadowCallStack:
693     return bitc::ATTR_KIND_SHADOWCALLSTACK;
694   case Attribute::StrictFP:
695     return bitc::ATTR_KIND_STRICT_FP;
696   case Attribute::StructRet:
697     return bitc::ATTR_KIND_STRUCT_RET;
698   case Attribute::SanitizeAddress:
699     return bitc::ATTR_KIND_SANITIZE_ADDRESS;
700   case Attribute::SanitizeHWAddress:
701     return bitc::ATTR_KIND_SANITIZE_HWADDRESS;
702   case Attribute::SanitizeThread:
703     return bitc::ATTR_KIND_SANITIZE_THREAD;
704   case Attribute::SanitizeMemory:
705     return bitc::ATTR_KIND_SANITIZE_MEMORY;
706   case Attribute::SpeculativeLoadHardening:
707     return bitc::ATTR_KIND_SPECULATIVE_LOAD_HARDENING;
708   case Attribute::SwiftError:
709     return bitc::ATTR_KIND_SWIFT_ERROR;
710   case Attribute::SwiftSelf:
711     return bitc::ATTR_KIND_SWIFT_SELF;
712   case Attribute::UWTable:
713     return bitc::ATTR_KIND_UW_TABLE;
714   case Attribute::WillReturn:
715     return bitc::ATTR_KIND_WILLRETURN;
716   case Attribute::WriteOnly:
717     return bitc::ATTR_KIND_WRITEONLY;
718   case Attribute::ZExt:
719     return bitc::ATTR_KIND_Z_EXT;
720   case Attribute::ImmArg:
721     return bitc::ATTR_KIND_IMMARG;
722   case Attribute::EndAttrKinds:
723     llvm_unreachable("Can not encode end-attribute kinds marker.");
724   case Attribute::None:
725     llvm_unreachable("Can not encode none-attribute.");
726   }
727 
728   llvm_unreachable("Trying to encode unknown attribute");
729 }
730 
731 void ModuleBitcodeWriter::writeAttributeGroupTable() {
732   const std::vector<ValueEnumerator::IndexAndAttrSet> &AttrGrps =
733       VE.getAttributeGroups();
734   if (AttrGrps.empty()) return;
735 
736   Stream.EnterSubblock(bitc::PARAMATTR_GROUP_BLOCK_ID, 3);
737 
738   SmallVector<uint64_t, 64> Record;
739   for (ValueEnumerator::IndexAndAttrSet Pair : AttrGrps) {
740     unsigned AttrListIndex = Pair.first;
741     AttributeSet AS = Pair.second;
742     Record.push_back(VE.getAttributeGroupID(Pair));
743     Record.push_back(AttrListIndex);
744 
745     for (Attribute Attr : AS) {
746       if (Attr.isEnumAttribute()) {
747         Record.push_back(0);
748         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
749       } else if (Attr.isIntAttribute()) {
750         Record.push_back(1);
751         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
752         Record.push_back(Attr.getValueAsInt());
753       } else if (Attr.isStringAttribute()) {
754         StringRef Kind = Attr.getKindAsString();
755         StringRef Val = Attr.getValueAsString();
756 
757         Record.push_back(Val.empty() ? 3 : 4);
758         Record.append(Kind.begin(), Kind.end());
759         Record.push_back(0);
760         if (!Val.empty()) {
761           Record.append(Val.begin(), Val.end());
762           Record.push_back(0);
763         }
764       } else {
765         assert(Attr.isTypeAttribute());
766         Type *Ty = Attr.getValueAsType();
767         Record.push_back(Ty ? 6 : 5);
768         Record.push_back(getAttrKindEncoding(Attr.getKindAsEnum()));
769         if (Ty)
770           Record.push_back(VE.getTypeID(Attr.getValueAsType()));
771       }
772     }
773 
774     Stream.EmitRecord(bitc::PARAMATTR_GRP_CODE_ENTRY, Record);
775     Record.clear();
776   }
777 
778   Stream.ExitBlock();
779 }
780 
781 void ModuleBitcodeWriter::writeAttributeTable() {
782   const std::vector<AttributeList> &Attrs = VE.getAttributeLists();
783   if (Attrs.empty()) return;
784 
785   Stream.EnterSubblock(bitc::PARAMATTR_BLOCK_ID, 3);
786 
787   SmallVector<uint64_t, 64> Record;
788   for (unsigned i = 0, e = Attrs.size(); i != e; ++i) {
789     AttributeList AL = Attrs[i];
790     for (unsigned i = AL.index_begin(), e = AL.index_end(); i != e; ++i) {
791       AttributeSet AS = AL.getAttributes(i);
792       if (AS.hasAttributes())
793         Record.push_back(VE.getAttributeGroupID({i, AS}));
794     }
795 
796     Stream.EmitRecord(bitc::PARAMATTR_CODE_ENTRY, Record);
797     Record.clear();
798   }
799 
800   Stream.ExitBlock();
801 }
802 
803 /// WriteTypeTable - Write out the type table for a module.
804 void ModuleBitcodeWriter::writeTypeTable() {
805   const ValueEnumerator::TypeList &TypeList = VE.getTypes();
806 
807   Stream.EnterSubblock(bitc::TYPE_BLOCK_ID_NEW, 4 /*count from # abbrevs */);
808   SmallVector<uint64_t, 64> TypeVals;
809 
810   uint64_t NumBits = VE.computeBitsRequiredForTypeIndicies();
811 
812   // Abbrev for TYPE_CODE_POINTER.
813   auto Abbv = std::make_shared<BitCodeAbbrev>();
814   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_POINTER));
815   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
816   Abbv->Add(BitCodeAbbrevOp(0));  // Addrspace = 0
817   unsigned PtrAbbrev = Stream.EmitAbbrev(std::move(Abbv));
818 
819   // Abbrev for TYPE_CODE_FUNCTION.
820   Abbv = std::make_shared<BitCodeAbbrev>();
821   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_FUNCTION));
822   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // isvararg
823   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
824   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
825   unsigned FunctionAbbrev = Stream.EmitAbbrev(std::move(Abbv));
826 
827   // Abbrev for TYPE_CODE_STRUCT_ANON.
828   Abbv = std::make_shared<BitCodeAbbrev>();
829   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_ANON));
830   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
831   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
832   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
833   unsigned StructAnonAbbrev = Stream.EmitAbbrev(std::move(Abbv));
834 
835   // Abbrev for TYPE_CODE_STRUCT_NAME.
836   Abbv = std::make_shared<BitCodeAbbrev>();
837   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAME));
838   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
839   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
840   unsigned StructNameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
841 
842   // Abbrev for TYPE_CODE_STRUCT_NAMED.
843   Abbv = std::make_shared<BitCodeAbbrev>();
844   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_STRUCT_NAMED));
845   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));  // ispacked
846   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
847   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
848   unsigned StructNamedAbbrev = Stream.EmitAbbrev(std::move(Abbv));
849 
850   // Abbrev for TYPE_CODE_ARRAY.
851   Abbv = std::make_shared<BitCodeAbbrev>();
852   Abbv->Add(BitCodeAbbrevOp(bitc::TYPE_CODE_ARRAY));
853   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // size
854   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, NumBits));
855   unsigned ArrayAbbrev = Stream.EmitAbbrev(std::move(Abbv));
856 
857   // Emit an entry count so the reader can reserve space.
858   TypeVals.push_back(TypeList.size());
859   Stream.EmitRecord(bitc::TYPE_CODE_NUMENTRY, TypeVals);
860   TypeVals.clear();
861 
862   // Loop over all of the types, emitting each in turn.
863   for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
864     Type *T = TypeList[i];
865     int AbbrevToUse = 0;
866     unsigned Code = 0;
867 
868     switch (T->getTypeID()) {
869     case Type::VoidTyID:      Code = bitc::TYPE_CODE_VOID;      break;
870     case Type::HalfTyID:      Code = bitc::TYPE_CODE_HALF;      break;
871     case Type::FloatTyID:     Code = bitc::TYPE_CODE_FLOAT;     break;
872     case Type::DoubleTyID:    Code = bitc::TYPE_CODE_DOUBLE;    break;
873     case Type::X86_FP80TyID:  Code = bitc::TYPE_CODE_X86_FP80;  break;
874     case Type::FP128TyID:     Code = bitc::TYPE_CODE_FP128;     break;
875     case Type::PPC_FP128TyID: Code = bitc::TYPE_CODE_PPC_FP128; break;
876     case Type::LabelTyID:     Code = bitc::TYPE_CODE_LABEL;     break;
877     case Type::MetadataTyID:  Code = bitc::TYPE_CODE_METADATA;  break;
878     case Type::X86_MMXTyID:   Code = bitc::TYPE_CODE_X86_MMX;   break;
879     case Type::TokenTyID:     Code = bitc::TYPE_CODE_TOKEN;     break;
880     case Type::IntegerTyID:
881       // INTEGER: [width]
882       Code = bitc::TYPE_CODE_INTEGER;
883       TypeVals.push_back(cast<IntegerType>(T)->getBitWidth());
884       break;
885     case Type::PointerTyID: {
886       PointerType *PTy = cast<PointerType>(T);
887       // POINTER: [pointee type, address space]
888       Code = bitc::TYPE_CODE_POINTER;
889       TypeVals.push_back(VE.getTypeID(PTy->getElementType()));
890       unsigned AddressSpace = PTy->getAddressSpace();
891       TypeVals.push_back(AddressSpace);
892       if (AddressSpace == 0) AbbrevToUse = PtrAbbrev;
893       break;
894     }
895     case Type::FunctionTyID: {
896       FunctionType *FT = cast<FunctionType>(T);
897       // FUNCTION: [isvararg, retty, paramty x N]
898       Code = bitc::TYPE_CODE_FUNCTION;
899       TypeVals.push_back(FT->isVarArg());
900       TypeVals.push_back(VE.getTypeID(FT->getReturnType()));
901       for (unsigned i = 0, e = FT->getNumParams(); i != e; ++i)
902         TypeVals.push_back(VE.getTypeID(FT->getParamType(i)));
903       AbbrevToUse = FunctionAbbrev;
904       break;
905     }
906     case Type::StructTyID: {
907       StructType *ST = cast<StructType>(T);
908       // STRUCT: [ispacked, eltty x N]
909       TypeVals.push_back(ST->isPacked());
910       // Output all of the element types.
911       for (StructType::element_iterator I = ST->element_begin(),
912            E = ST->element_end(); I != E; ++I)
913         TypeVals.push_back(VE.getTypeID(*I));
914 
915       if (ST->isLiteral()) {
916         Code = bitc::TYPE_CODE_STRUCT_ANON;
917         AbbrevToUse = StructAnonAbbrev;
918       } else {
919         if (ST->isOpaque()) {
920           Code = bitc::TYPE_CODE_OPAQUE;
921         } else {
922           Code = bitc::TYPE_CODE_STRUCT_NAMED;
923           AbbrevToUse = StructNamedAbbrev;
924         }
925 
926         // Emit the name if it is present.
927         if (!ST->getName().empty())
928           writeStringRecord(Stream, bitc::TYPE_CODE_STRUCT_NAME, ST->getName(),
929                             StructNameAbbrev);
930       }
931       break;
932     }
933     case Type::ArrayTyID: {
934       ArrayType *AT = cast<ArrayType>(T);
935       // ARRAY: [numelts, eltty]
936       Code = bitc::TYPE_CODE_ARRAY;
937       TypeVals.push_back(AT->getNumElements());
938       TypeVals.push_back(VE.getTypeID(AT->getElementType()));
939       AbbrevToUse = ArrayAbbrev;
940       break;
941     }
942     case Type::VectorTyID: {
943       VectorType *VT = cast<VectorType>(T);
944       // VECTOR [numelts, eltty] or
945       //        [numelts, eltty, scalable]
946       Code = bitc::TYPE_CODE_VECTOR;
947       TypeVals.push_back(VT->getNumElements());
948       TypeVals.push_back(VE.getTypeID(VT->getElementType()));
949       if (VT->isScalable())
950         TypeVals.push_back(VT->isScalable());
951       break;
952     }
953     }
954 
955     // Emit the finished record.
956     Stream.EmitRecord(Code, TypeVals, AbbrevToUse);
957     TypeVals.clear();
958   }
959 
960   Stream.ExitBlock();
961 }
962 
963 static unsigned getEncodedLinkage(const GlobalValue::LinkageTypes Linkage) {
964   switch (Linkage) {
965   case GlobalValue::ExternalLinkage:
966     return 0;
967   case GlobalValue::WeakAnyLinkage:
968     return 16;
969   case GlobalValue::AppendingLinkage:
970     return 2;
971   case GlobalValue::InternalLinkage:
972     return 3;
973   case GlobalValue::LinkOnceAnyLinkage:
974     return 18;
975   case GlobalValue::ExternalWeakLinkage:
976     return 7;
977   case GlobalValue::CommonLinkage:
978     return 8;
979   case GlobalValue::PrivateLinkage:
980     return 9;
981   case GlobalValue::WeakODRLinkage:
982     return 17;
983   case GlobalValue::LinkOnceODRLinkage:
984     return 19;
985   case GlobalValue::AvailableExternallyLinkage:
986     return 12;
987   }
988   llvm_unreachable("Invalid linkage");
989 }
990 
991 static unsigned getEncodedLinkage(const GlobalValue &GV) {
992   return getEncodedLinkage(GV.getLinkage());
993 }
994 
995 static uint64_t getEncodedFFlags(FunctionSummary::FFlags Flags) {
996   uint64_t RawFlags = 0;
997   RawFlags |= Flags.ReadNone;
998   RawFlags |= (Flags.ReadOnly << 1);
999   RawFlags |= (Flags.NoRecurse << 2);
1000   RawFlags |= (Flags.ReturnDoesNotAlias << 3);
1001   RawFlags |= (Flags.NoInline << 4);
1002   return RawFlags;
1003 }
1004 
1005 // Decode the flags for GlobalValue in the summary
1006 static uint64_t getEncodedGVSummaryFlags(GlobalValueSummary::GVFlags Flags) {
1007   uint64_t RawFlags = 0;
1008 
1009   RawFlags |= Flags.NotEligibleToImport; // bool
1010   RawFlags |= (Flags.Live << 1);
1011   RawFlags |= (Flags.DSOLocal << 2);
1012   RawFlags |= (Flags.CanAutoHide << 3);
1013 
1014   // Linkage don't need to be remapped at that time for the summary. Any future
1015   // change to the getEncodedLinkage() function will need to be taken into
1016   // account here as well.
1017   RawFlags = (RawFlags << 4) | Flags.Linkage; // 4 bits
1018 
1019   return RawFlags;
1020 }
1021 
1022 static uint64_t getEncodedGVarFlags(GlobalVarSummary::GVarFlags Flags) {
1023   uint64_t RawFlags = Flags.MaybeReadOnly | (Flags.MaybeWriteOnly << 1);
1024   return RawFlags;
1025 }
1026 
1027 static unsigned getEncodedVisibility(const GlobalValue &GV) {
1028   switch (GV.getVisibility()) {
1029   case GlobalValue::DefaultVisibility:   return 0;
1030   case GlobalValue::HiddenVisibility:    return 1;
1031   case GlobalValue::ProtectedVisibility: return 2;
1032   }
1033   llvm_unreachable("Invalid visibility");
1034 }
1035 
1036 static unsigned getEncodedDLLStorageClass(const GlobalValue &GV) {
1037   switch (GV.getDLLStorageClass()) {
1038   case GlobalValue::DefaultStorageClass:   return 0;
1039   case GlobalValue::DLLImportStorageClass: return 1;
1040   case GlobalValue::DLLExportStorageClass: return 2;
1041   }
1042   llvm_unreachable("Invalid DLL storage class");
1043 }
1044 
1045 static unsigned getEncodedThreadLocalMode(const GlobalValue &GV) {
1046   switch (GV.getThreadLocalMode()) {
1047     case GlobalVariable::NotThreadLocal:         return 0;
1048     case GlobalVariable::GeneralDynamicTLSModel: return 1;
1049     case GlobalVariable::LocalDynamicTLSModel:   return 2;
1050     case GlobalVariable::InitialExecTLSModel:    return 3;
1051     case GlobalVariable::LocalExecTLSModel:      return 4;
1052   }
1053   llvm_unreachable("Invalid TLS model");
1054 }
1055 
1056 static unsigned getEncodedComdatSelectionKind(const Comdat &C) {
1057   switch (C.getSelectionKind()) {
1058   case Comdat::Any:
1059     return bitc::COMDAT_SELECTION_KIND_ANY;
1060   case Comdat::ExactMatch:
1061     return bitc::COMDAT_SELECTION_KIND_EXACT_MATCH;
1062   case Comdat::Largest:
1063     return bitc::COMDAT_SELECTION_KIND_LARGEST;
1064   case Comdat::NoDuplicates:
1065     return bitc::COMDAT_SELECTION_KIND_NO_DUPLICATES;
1066   case Comdat::SameSize:
1067     return bitc::COMDAT_SELECTION_KIND_SAME_SIZE;
1068   }
1069   llvm_unreachable("Invalid selection kind");
1070 }
1071 
1072 static unsigned getEncodedUnnamedAddr(const GlobalValue &GV) {
1073   switch (GV.getUnnamedAddr()) {
1074   case GlobalValue::UnnamedAddr::None:   return 0;
1075   case GlobalValue::UnnamedAddr::Local:  return 2;
1076   case GlobalValue::UnnamedAddr::Global: return 1;
1077   }
1078   llvm_unreachable("Invalid unnamed_addr");
1079 }
1080 
1081 size_t ModuleBitcodeWriter::addToStrtab(StringRef Str) {
1082   if (GenerateHash)
1083     Hasher.update(Str);
1084   return StrtabBuilder.add(Str);
1085 }
1086 
1087 void ModuleBitcodeWriter::writeComdats() {
1088   SmallVector<unsigned, 64> Vals;
1089   for (const Comdat *C : VE.getComdats()) {
1090     // COMDAT: [strtab offset, strtab size, selection_kind]
1091     Vals.push_back(addToStrtab(C->getName()));
1092     Vals.push_back(C->getName().size());
1093     Vals.push_back(getEncodedComdatSelectionKind(*C));
1094     Stream.EmitRecord(bitc::MODULE_CODE_COMDAT, Vals, /*AbbrevToUse=*/0);
1095     Vals.clear();
1096   }
1097 }
1098 
1099 /// Write a record that will eventually hold the word offset of the
1100 /// module-level VST. For now the offset is 0, which will be backpatched
1101 /// after the real VST is written. Saves the bit offset to backpatch.
1102 void ModuleBitcodeWriter::writeValueSymbolTableForwardDecl() {
1103   // Write a placeholder value in for the offset of the real VST,
1104   // which is written after the function blocks so that it can include
1105   // the offset of each function. The placeholder offset will be
1106   // updated when the real VST is written.
1107   auto Abbv = std::make_shared<BitCodeAbbrev>();
1108   Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_VSTOFFSET));
1109   // Blocks are 32-bit aligned, so we can use a 32-bit word offset to
1110   // hold the real VST offset. Must use fixed instead of VBR as we don't
1111   // know how many VBR chunks to reserve ahead of time.
1112   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
1113   unsigned VSTOffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1114 
1115   // Emit the placeholder
1116   uint64_t Vals[] = {bitc::MODULE_CODE_VSTOFFSET, 0};
1117   Stream.EmitRecordWithAbbrev(VSTOffsetAbbrev, Vals);
1118 
1119   // Compute and save the bit offset to the placeholder, which will be
1120   // patched when the real VST is written. We can simply subtract the 32-bit
1121   // fixed size from the current bit number to get the location to backpatch.
1122   VSTOffsetPlaceholder = Stream.GetCurrentBitNo() - 32;
1123 }
1124 
1125 enum StringEncoding { SE_Char6, SE_Fixed7, SE_Fixed8 };
1126 
1127 /// Determine the encoding to use for the given string name and length.
1128 static StringEncoding getStringEncoding(StringRef Str) {
1129   bool isChar6 = true;
1130   for (char C : Str) {
1131     if (isChar6)
1132       isChar6 = BitCodeAbbrevOp::isChar6(C);
1133     if ((unsigned char)C & 128)
1134       // don't bother scanning the rest.
1135       return SE_Fixed8;
1136   }
1137   if (isChar6)
1138     return SE_Char6;
1139   return SE_Fixed7;
1140 }
1141 
1142 /// Emit top-level description of module, including target triple, inline asm,
1143 /// descriptors for global variables, and function prototype info.
1144 /// Returns the bit offset to backpatch with the location of the real VST.
1145 void ModuleBitcodeWriter::writeModuleInfo() {
1146   // Emit various pieces of data attached to a module.
1147   if (!M.getTargetTriple().empty())
1148     writeStringRecord(Stream, bitc::MODULE_CODE_TRIPLE, M.getTargetTriple(),
1149                       0 /*TODO*/);
1150   const std::string &DL = M.getDataLayoutStr();
1151   if (!DL.empty())
1152     writeStringRecord(Stream, bitc::MODULE_CODE_DATALAYOUT, DL, 0 /*TODO*/);
1153   if (!M.getModuleInlineAsm().empty())
1154     writeStringRecord(Stream, bitc::MODULE_CODE_ASM, M.getModuleInlineAsm(),
1155                       0 /*TODO*/);
1156 
1157   // Emit information about sections and GC, computing how many there are. Also
1158   // compute the maximum alignment value.
1159   std::map<std::string, unsigned> SectionMap;
1160   std::map<std::string, unsigned> GCMap;
1161   unsigned MaxAlignment = 0;
1162   unsigned MaxGlobalType = 0;
1163   for (const GlobalValue &GV : M.globals()) {
1164     MaxAlignment = std::max(MaxAlignment, GV.getAlignment());
1165     MaxGlobalType = std::max(MaxGlobalType, VE.getTypeID(GV.getValueType()));
1166     if (GV.hasSection()) {
1167       // Give section names unique ID's.
1168       unsigned &Entry = SectionMap[GV.getSection()];
1169       if (!Entry) {
1170         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, GV.getSection(),
1171                           0 /*TODO*/);
1172         Entry = SectionMap.size();
1173       }
1174     }
1175   }
1176   for (const Function &F : M) {
1177     MaxAlignment = std::max(MaxAlignment, F.getAlignment());
1178     if (F.hasSection()) {
1179       // Give section names unique ID's.
1180       unsigned &Entry = SectionMap[F.getSection()];
1181       if (!Entry) {
1182         writeStringRecord(Stream, bitc::MODULE_CODE_SECTIONNAME, F.getSection(),
1183                           0 /*TODO*/);
1184         Entry = SectionMap.size();
1185       }
1186     }
1187     if (F.hasGC()) {
1188       // Same for GC names.
1189       unsigned &Entry = GCMap[F.getGC()];
1190       if (!Entry) {
1191         writeStringRecord(Stream, bitc::MODULE_CODE_GCNAME, F.getGC(),
1192                           0 /*TODO*/);
1193         Entry = GCMap.size();
1194       }
1195     }
1196   }
1197 
1198   // Emit abbrev for globals, now that we know # sections and max alignment.
1199   unsigned SimpleGVarAbbrev = 0;
1200   if (!M.global_empty()) {
1201     // Add an abbrev for common globals with no visibility or thread localness.
1202     auto Abbv = std::make_shared<BitCodeAbbrev>();
1203     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_GLOBALVAR));
1204     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1205     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1206     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1207                               Log2_32_Ceil(MaxGlobalType+1)));
1208     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // AddrSpace << 2
1209                                                            //| explicitType << 1
1210                                                            //| constant
1211     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // Initializer.
1212     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 5)); // Linkage.
1213     if (MaxAlignment == 0)                                 // Alignment.
1214       Abbv->Add(BitCodeAbbrevOp(0));
1215     else {
1216       unsigned MaxEncAlignment = Log2_32(MaxAlignment)+1;
1217       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1218                                Log2_32_Ceil(MaxEncAlignment+1)));
1219     }
1220     if (SectionMap.empty())                                    // Section.
1221       Abbv->Add(BitCodeAbbrevOp(0));
1222     else
1223       Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
1224                                Log2_32_Ceil(SectionMap.size()+1)));
1225     // Don't bother emitting vis + thread local.
1226     SimpleGVarAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1227   }
1228 
1229   SmallVector<unsigned, 64> Vals;
1230   // Emit the module's source file name.
1231   {
1232     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
1233     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
1234     if (Bits == SE_Char6)
1235       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
1236     else if (Bits == SE_Fixed7)
1237       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
1238 
1239     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
1240     auto Abbv = std::make_shared<BitCodeAbbrev>();
1241     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
1242     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1243     Abbv->Add(AbbrevOpToUse);
1244     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
1245 
1246     for (const auto P : M.getSourceFileName())
1247       Vals.push_back((unsigned char)P);
1248 
1249     // Emit the finished record.
1250     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
1251     Vals.clear();
1252   }
1253 
1254   // Emit the global variable information.
1255   for (const GlobalVariable &GV : M.globals()) {
1256     unsigned AbbrevToUse = 0;
1257 
1258     // GLOBALVAR: [strtab offset, strtab size, type, isconst, initid,
1259     //             linkage, alignment, section, visibility, threadlocal,
1260     //             unnamed_addr, externally_initialized, dllstorageclass,
1261     //             comdat, attributes, DSO_Local]
1262     Vals.push_back(addToStrtab(GV.getName()));
1263     Vals.push_back(GV.getName().size());
1264     Vals.push_back(VE.getTypeID(GV.getValueType()));
1265     Vals.push_back(GV.getType()->getAddressSpace() << 2 | 2 | GV.isConstant());
1266     Vals.push_back(GV.isDeclaration() ? 0 :
1267                    (VE.getValueID(GV.getInitializer()) + 1));
1268     Vals.push_back(getEncodedLinkage(GV));
1269     Vals.push_back(Log2_32(GV.getAlignment())+1);
1270     Vals.push_back(GV.hasSection() ? SectionMap[GV.getSection()] : 0);
1271     if (GV.isThreadLocal() ||
1272         GV.getVisibility() != GlobalValue::DefaultVisibility ||
1273         GV.getUnnamedAddr() != GlobalValue::UnnamedAddr::None ||
1274         GV.isExternallyInitialized() ||
1275         GV.getDLLStorageClass() != GlobalValue::DefaultStorageClass ||
1276         GV.hasComdat() ||
1277         GV.hasAttributes() ||
1278         GV.isDSOLocal() ||
1279         GV.hasPartition()) {
1280       Vals.push_back(getEncodedVisibility(GV));
1281       Vals.push_back(getEncodedThreadLocalMode(GV));
1282       Vals.push_back(getEncodedUnnamedAddr(GV));
1283       Vals.push_back(GV.isExternallyInitialized());
1284       Vals.push_back(getEncodedDLLStorageClass(GV));
1285       Vals.push_back(GV.hasComdat() ? VE.getComdatID(GV.getComdat()) : 0);
1286 
1287       auto AL = GV.getAttributesAsList(AttributeList::FunctionIndex);
1288       Vals.push_back(VE.getAttributeListID(AL));
1289 
1290       Vals.push_back(GV.isDSOLocal());
1291       Vals.push_back(addToStrtab(GV.getPartition()));
1292       Vals.push_back(GV.getPartition().size());
1293     } else {
1294       AbbrevToUse = SimpleGVarAbbrev;
1295     }
1296 
1297     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals, AbbrevToUse);
1298     Vals.clear();
1299   }
1300 
1301   // Emit the function proto information.
1302   for (const Function &F : M) {
1303     // FUNCTION:  [strtab offset, strtab size, type, callingconv, isproto,
1304     //             linkage, paramattrs, alignment, section, visibility, gc,
1305     //             unnamed_addr, prologuedata, dllstorageclass, comdat,
1306     //             prefixdata, personalityfn, DSO_Local, addrspace]
1307     Vals.push_back(addToStrtab(F.getName()));
1308     Vals.push_back(F.getName().size());
1309     Vals.push_back(VE.getTypeID(F.getFunctionType()));
1310     Vals.push_back(F.getCallingConv());
1311     Vals.push_back(F.isDeclaration());
1312     Vals.push_back(getEncodedLinkage(F));
1313     Vals.push_back(VE.getAttributeListID(F.getAttributes()));
1314     Vals.push_back(Log2_32(F.getAlignment())+1);
1315     Vals.push_back(F.hasSection() ? SectionMap[F.getSection()] : 0);
1316     Vals.push_back(getEncodedVisibility(F));
1317     Vals.push_back(F.hasGC() ? GCMap[F.getGC()] : 0);
1318     Vals.push_back(getEncodedUnnamedAddr(F));
1319     Vals.push_back(F.hasPrologueData() ? (VE.getValueID(F.getPrologueData()) + 1)
1320                                        : 0);
1321     Vals.push_back(getEncodedDLLStorageClass(F));
1322     Vals.push_back(F.hasComdat() ? VE.getComdatID(F.getComdat()) : 0);
1323     Vals.push_back(F.hasPrefixData() ? (VE.getValueID(F.getPrefixData()) + 1)
1324                                      : 0);
1325     Vals.push_back(
1326         F.hasPersonalityFn() ? (VE.getValueID(F.getPersonalityFn()) + 1) : 0);
1327 
1328     Vals.push_back(F.isDSOLocal());
1329     Vals.push_back(F.getAddressSpace());
1330     Vals.push_back(addToStrtab(F.getPartition()));
1331     Vals.push_back(F.getPartition().size());
1332 
1333     unsigned AbbrevToUse = 0;
1334     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals, AbbrevToUse);
1335     Vals.clear();
1336   }
1337 
1338   // Emit the alias information.
1339   for (const GlobalAlias &A : M.aliases()) {
1340     // ALIAS: [strtab offset, strtab size, alias type, aliasee val#, linkage,
1341     //         visibility, dllstorageclass, threadlocal, unnamed_addr,
1342     //         DSO_Local]
1343     Vals.push_back(addToStrtab(A.getName()));
1344     Vals.push_back(A.getName().size());
1345     Vals.push_back(VE.getTypeID(A.getValueType()));
1346     Vals.push_back(A.getType()->getAddressSpace());
1347     Vals.push_back(VE.getValueID(A.getAliasee()));
1348     Vals.push_back(getEncodedLinkage(A));
1349     Vals.push_back(getEncodedVisibility(A));
1350     Vals.push_back(getEncodedDLLStorageClass(A));
1351     Vals.push_back(getEncodedThreadLocalMode(A));
1352     Vals.push_back(getEncodedUnnamedAddr(A));
1353     Vals.push_back(A.isDSOLocal());
1354     Vals.push_back(addToStrtab(A.getPartition()));
1355     Vals.push_back(A.getPartition().size());
1356 
1357     unsigned AbbrevToUse = 0;
1358     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals, AbbrevToUse);
1359     Vals.clear();
1360   }
1361 
1362   // Emit the ifunc information.
1363   for (const GlobalIFunc &I : M.ifuncs()) {
1364     // IFUNC: [strtab offset, strtab size, ifunc type, address space, resolver
1365     //         val#, linkage, visibility, DSO_Local]
1366     Vals.push_back(addToStrtab(I.getName()));
1367     Vals.push_back(I.getName().size());
1368     Vals.push_back(VE.getTypeID(I.getValueType()));
1369     Vals.push_back(I.getType()->getAddressSpace());
1370     Vals.push_back(VE.getValueID(I.getResolver()));
1371     Vals.push_back(getEncodedLinkage(I));
1372     Vals.push_back(getEncodedVisibility(I));
1373     Vals.push_back(I.isDSOLocal());
1374     Vals.push_back(addToStrtab(I.getPartition()));
1375     Vals.push_back(I.getPartition().size());
1376     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
1377     Vals.clear();
1378   }
1379 
1380   writeValueSymbolTableForwardDecl();
1381 }
1382 
1383 static uint64_t getOptimizationFlags(const Value *V) {
1384   uint64_t Flags = 0;
1385 
1386   if (const auto *OBO = dyn_cast<OverflowingBinaryOperator>(V)) {
1387     if (OBO->hasNoSignedWrap())
1388       Flags |= 1 << bitc::OBO_NO_SIGNED_WRAP;
1389     if (OBO->hasNoUnsignedWrap())
1390       Flags |= 1 << bitc::OBO_NO_UNSIGNED_WRAP;
1391   } else if (const auto *PEO = dyn_cast<PossiblyExactOperator>(V)) {
1392     if (PEO->isExact())
1393       Flags |= 1 << bitc::PEO_EXACT;
1394   } else if (const auto *FPMO = dyn_cast<FPMathOperator>(V)) {
1395     if (FPMO->hasAllowReassoc())
1396       Flags |= bitc::AllowReassoc;
1397     if (FPMO->hasNoNaNs())
1398       Flags |= bitc::NoNaNs;
1399     if (FPMO->hasNoInfs())
1400       Flags |= bitc::NoInfs;
1401     if (FPMO->hasNoSignedZeros())
1402       Flags |= bitc::NoSignedZeros;
1403     if (FPMO->hasAllowReciprocal())
1404       Flags |= bitc::AllowReciprocal;
1405     if (FPMO->hasAllowContract())
1406       Flags |= bitc::AllowContract;
1407     if (FPMO->hasApproxFunc())
1408       Flags |= bitc::ApproxFunc;
1409   }
1410 
1411   return Flags;
1412 }
1413 
1414 void ModuleBitcodeWriter::writeValueAsMetadata(
1415     const ValueAsMetadata *MD, SmallVectorImpl<uint64_t> &Record) {
1416   // Mimic an MDNode with a value as one operand.
1417   Value *V = MD->getValue();
1418   Record.push_back(VE.getTypeID(V->getType()));
1419   Record.push_back(VE.getValueID(V));
1420   Stream.EmitRecord(bitc::METADATA_VALUE, Record, 0);
1421   Record.clear();
1422 }
1423 
1424 void ModuleBitcodeWriter::writeMDTuple(const MDTuple *N,
1425                                        SmallVectorImpl<uint64_t> &Record,
1426                                        unsigned Abbrev) {
1427   for (unsigned i = 0, e = N->getNumOperands(); i != e; ++i) {
1428     Metadata *MD = N->getOperand(i);
1429     assert(!(MD && isa<LocalAsMetadata>(MD)) &&
1430            "Unexpected function-local metadata");
1431     Record.push_back(VE.getMetadataOrNullID(MD));
1432   }
1433   Stream.EmitRecord(N->isDistinct() ? bitc::METADATA_DISTINCT_NODE
1434                                     : bitc::METADATA_NODE,
1435                     Record, Abbrev);
1436   Record.clear();
1437 }
1438 
1439 unsigned ModuleBitcodeWriter::createDILocationAbbrev() {
1440   // Assume the column is usually under 128, and always output the inlined-at
1441   // location (it's never more expensive than building an array size 1).
1442   auto Abbv = std::make_shared<BitCodeAbbrev>();
1443   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_LOCATION));
1444   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1445   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1446   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
1447   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1448   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1449   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1450   return Stream.EmitAbbrev(std::move(Abbv));
1451 }
1452 
1453 void ModuleBitcodeWriter::writeDILocation(const DILocation *N,
1454                                           SmallVectorImpl<uint64_t> &Record,
1455                                           unsigned &Abbrev) {
1456   if (!Abbrev)
1457     Abbrev = createDILocationAbbrev();
1458 
1459   Record.push_back(N->isDistinct());
1460   Record.push_back(N->getLine());
1461   Record.push_back(N->getColumn());
1462   Record.push_back(VE.getMetadataID(N->getScope()));
1463   Record.push_back(VE.getMetadataOrNullID(N->getInlinedAt()));
1464   Record.push_back(N->isImplicitCode());
1465 
1466   Stream.EmitRecord(bitc::METADATA_LOCATION, Record, Abbrev);
1467   Record.clear();
1468 }
1469 
1470 unsigned ModuleBitcodeWriter::createGenericDINodeAbbrev() {
1471   // Assume the column is usually under 128, and always output the inlined-at
1472   // location (it's never more expensive than building an array size 1).
1473   auto Abbv = std::make_shared<BitCodeAbbrev>();
1474   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_GENERIC_DEBUG));
1475   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1476   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1477   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
1478   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1479   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1480   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
1481   return Stream.EmitAbbrev(std::move(Abbv));
1482 }
1483 
1484 void ModuleBitcodeWriter::writeGenericDINode(const GenericDINode *N,
1485                                              SmallVectorImpl<uint64_t> &Record,
1486                                              unsigned &Abbrev) {
1487   if (!Abbrev)
1488     Abbrev = createGenericDINodeAbbrev();
1489 
1490   Record.push_back(N->isDistinct());
1491   Record.push_back(N->getTag());
1492   Record.push_back(0); // Per-tag version field; unused for now.
1493 
1494   for (auto &I : N->operands())
1495     Record.push_back(VE.getMetadataOrNullID(I));
1496 
1497   Stream.EmitRecord(bitc::METADATA_GENERIC_DEBUG, Record, Abbrev);
1498   Record.clear();
1499 }
1500 
1501 static uint64_t rotateSign(int64_t I) {
1502   uint64_t U = I;
1503   return I < 0 ? ~(U << 1) : U << 1;
1504 }
1505 
1506 void ModuleBitcodeWriter::writeDISubrange(const DISubrange *N,
1507                                           SmallVectorImpl<uint64_t> &Record,
1508                                           unsigned Abbrev) {
1509   const uint64_t Version = 1 << 1;
1510   Record.push_back((uint64_t)N->isDistinct() | Version);
1511   Record.push_back(VE.getMetadataOrNullID(N->getRawCountNode()));
1512   Record.push_back(rotateSign(N->getLowerBound()));
1513 
1514   Stream.EmitRecord(bitc::METADATA_SUBRANGE, Record, Abbrev);
1515   Record.clear();
1516 }
1517 
1518 void ModuleBitcodeWriter::writeDIEnumerator(const DIEnumerator *N,
1519                                             SmallVectorImpl<uint64_t> &Record,
1520                                             unsigned Abbrev) {
1521   Record.push_back((N->isUnsigned() << 1) | N->isDistinct());
1522   Record.push_back(rotateSign(N->getValue()));
1523   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1524 
1525   Stream.EmitRecord(bitc::METADATA_ENUMERATOR, Record, Abbrev);
1526   Record.clear();
1527 }
1528 
1529 void ModuleBitcodeWriter::writeDIBasicType(const DIBasicType *N,
1530                                            SmallVectorImpl<uint64_t> &Record,
1531                                            unsigned Abbrev) {
1532   Record.push_back(N->isDistinct());
1533   Record.push_back(N->getTag());
1534   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1535   Record.push_back(N->getSizeInBits());
1536   Record.push_back(N->getAlignInBits());
1537   Record.push_back(N->getEncoding());
1538   Record.push_back(N->getFlags());
1539 
1540   Stream.EmitRecord(bitc::METADATA_BASIC_TYPE, Record, Abbrev);
1541   Record.clear();
1542 }
1543 
1544 void ModuleBitcodeWriter::writeDIDerivedType(const DIDerivedType *N,
1545                                              SmallVectorImpl<uint64_t> &Record,
1546                                              unsigned Abbrev) {
1547   Record.push_back(N->isDistinct());
1548   Record.push_back(N->getTag());
1549   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1550   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1551   Record.push_back(N->getLine());
1552   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1553   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1554   Record.push_back(N->getSizeInBits());
1555   Record.push_back(N->getAlignInBits());
1556   Record.push_back(N->getOffsetInBits());
1557   Record.push_back(N->getFlags());
1558   Record.push_back(VE.getMetadataOrNullID(N->getExtraData()));
1559 
1560   // DWARF address space is encoded as N->getDWARFAddressSpace() + 1. 0 means
1561   // that there is no DWARF address space associated with DIDerivedType.
1562   if (const auto &DWARFAddressSpace = N->getDWARFAddressSpace())
1563     Record.push_back(*DWARFAddressSpace + 1);
1564   else
1565     Record.push_back(0);
1566 
1567   Stream.EmitRecord(bitc::METADATA_DERIVED_TYPE, Record, Abbrev);
1568   Record.clear();
1569 }
1570 
1571 void ModuleBitcodeWriter::writeDICompositeType(
1572     const DICompositeType *N, SmallVectorImpl<uint64_t> &Record,
1573     unsigned Abbrev) {
1574   const unsigned IsNotUsedInOldTypeRef = 0x2;
1575   Record.push_back(IsNotUsedInOldTypeRef | (unsigned)N->isDistinct());
1576   Record.push_back(N->getTag());
1577   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1578   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1579   Record.push_back(N->getLine());
1580   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1581   Record.push_back(VE.getMetadataOrNullID(N->getBaseType()));
1582   Record.push_back(N->getSizeInBits());
1583   Record.push_back(N->getAlignInBits());
1584   Record.push_back(N->getOffsetInBits());
1585   Record.push_back(N->getFlags());
1586   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1587   Record.push_back(N->getRuntimeLang());
1588   Record.push_back(VE.getMetadataOrNullID(N->getVTableHolder()));
1589   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1590   Record.push_back(VE.getMetadataOrNullID(N->getRawIdentifier()));
1591   Record.push_back(VE.getMetadataOrNullID(N->getDiscriminator()));
1592 
1593   Stream.EmitRecord(bitc::METADATA_COMPOSITE_TYPE, Record, Abbrev);
1594   Record.clear();
1595 }
1596 
1597 void ModuleBitcodeWriter::writeDISubroutineType(
1598     const DISubroutineType *N, SmallVectorImpl<uint64_t> &Record,
1599     unsigned Abbrev) {
1600   const unsigned HasNoOldTypeRefs = 0x2;
1601   Record.push_back(HasNoOldTypeRefs | (unsigned)N->isDistinct());
1602   Record.push_back(N->getFlags());
1603   Record.push_back(VE.getMetadataOrNullID(N->getTypeArray().get()));
1604   Record.push_back(N->getCC());
1605 
1606   Stream.EmitRecord(bitc::METADATA_SUBROUTINE_TYPE, Record, Abbrev);
1607   Record.clear();
1608 }
1609 
1610 void ModuleBitcodeWriter::writeDIFile(const DIFile *N,
1611                                       SmallVectorImpl<uint64_t> &Record,
1612                                       unsigned Abbrev) {
1613   Record.push_back(N->isDistinct());
1614   Record.push_back(VE.getMetadataOrNullID(N->getRawFilename()));
1615   Record.push_back(VE.getMetadataOrNullID(N->getRawDirectory()));
1616   if (N->getRawChecksum()) {
1617     Record.push_back(N->getRawChecksum()->Kind);
1618     Record.push_back(VE.getMetadataOrNullID(N->getRawChecksum()->Value));
1619   } else {
1620     // Maintain backwards compatibility with the old internal representation of
1621     // CSK_None in ChecksumKind by writing nulls here when Checksum is None.
1622     Record.push_back(0);
1623     Record.push_back(VE.getMetadataOrNullID(nullptr));
1624   }
1625   auto Source = N->getRawSource();
1626   if (Source)
1627     Record.push_back(VE.getMetadataOrNullID(*Source));
1628 
1629   Stream.EmitRecord(bitc::METADATA_FILE, Record, Abbrev);
1630   Record.clear();
1631 }
1632 
1633 void ModuleBitcodeWriter::writeDICompileUnit(const DICompileUnit *N,
1634                                              SmallVectorImpl<uint64_t> &Record,
1635                                              unsigned Abbrev) {
1636   assert(N->isDistinct() && "Expected distinct compile units");
1637   Record.push_back(/* IsDistinct */ true);
1638   Record.push_back(N->getSourceLanguage());
1639   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1640   Record.push_back(VE.getMetadataOrNullID(N->getRawProducer()));
1641   Record.push_back(N->isOptimized());
1642   Record.push_back(VE.getMetadataOrNullID(N->getRawFlags()));
1643   Record.push_back(N->getRuntimeVersion());
1644   Record.push_back(VE.getMetadataOrNullID(N->getRawSplitDebugFilename()));
1645   Record.push_back(N->getEmissionKind());
1646   Record.push_back(VE.getMetadataOrNullID(N->getEnumTypes().get()));
1647   Record.push_back(VE.getMetadataOrNullID(N->getRetainedTypes().get()));
1648   Record.push_back(/* subprograms */ 0);
1649   Record.push_back(VE.getMetadataOrNullID(N->getGlobalVariables().get()));
1650   Record.push_back(VE.getMetadataOrNullID(N->getImportedEntities().get()));
1651   Record.push_back(N->getDWOId());
1652   Record.push_back(VE.getMetadataOrNullID(N->getMacros().get()));
1653   Record.push_back(N->getSplitDebugInlining());
1654   Record.push_back(N->getDebugInfoForProfiling());
1655   Record.push_back((unsigned)N->getNameTableKind());
1656 
1657   Stream.EmitRecord(bitc::METADATA_COMPILE_UNIT, Record, Abbrev);
1658   Record.clear();
1659 }
1660 
1661 void ModuleBitcodeWriter::writeDISubprogram(const DISubprogram *N,
1662                                             SmallVectorImpl<uint64_t> &Record,
1663                                             unsigned Abbrev) {
1664   const uint64_t HasUnitFlag = 1 << 1;
1665   const uint64_t HasSPFlagsFlag = 1 << 2;
1666   Record.push_back(uint64_t(N->isDistinct()) | HasUnitFlag | HasSPFlagsFlag);
1667   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1668   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1669   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1670   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1671   Record.push_back(N->getLine());
1672   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1673   Record.push_back(N->getScopeLine());
1674   Record.push_back(VE.getMetadataOrNullID(N->getContainingType()));
1675   Record.push_back(N->getSPFlags());
1676   Record.push_back(N->getVirtualIndex());
1677   Record.push_back(N->getFlags());
1678   Record.push_back(VE.getMetadataOrNullID(N->getRawUnit()));
1679   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams().get()));
1680   Record.push_back(VE.getMetadataOrNullID(N->getDeclaration()));
1681   Record.push_back(VE.getMetadataOrNullID(N->getRetainedNodes().get()));
1682   Record.push_back(N->getThisAdjustment());
1683   Record.push_back(VE.getMetadataOrNullID(N->getThrownTypes().get()));
1684 
1685   Stream.EmitRecord(bitc::METADATA_SUBPROGRAM, Record, Abbrev);
1686   Record.clear();
1687 }
1688 
1689 void ModuleBitcodeWriter::writeDILexicalBlock(const DILexicalBlock *N,
1690                                               SmallVectorImpl<uint64_t> &Record,
1691                                               unsigned Abbrev) {
1692   Record.push_back(N->isDistinct());
1693   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1694   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1695   Record.push_back(N->getLine());
1696   Record.push_back(N->getColumn());
1697 
1698   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK, Record, Abbrev);
1699   Record.clear();
1700 }
1701 
1702 void ModuleBitcodeWriter::writeDILexicalBlockFile(
1703     const DILexicalBlockFile *N, SmallVectorImpl<uint64_t> &Record,
1704     unsigned Abbrev) {
1705   Record.push_back(N->isDistinct());
1706   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1707   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1708   Record.push_back(N->getDiscriminator());
1709 
1710   Stream.EmitRecord(bitc::METADATA_LEXICAL_BLOCK_FILE, Record, Abbrev);
1711   Record.clear();
1712 }
1713 
1714 void ModuleBitcodeWriter::writeDICommonBlock(const DICommonBlock *N,
1715                                              SmallVectorImpl<uint64_t> &Record,
1716                                              unsigned Abbrev) {
1717   Record.push_back(N->isDistinct());
1718   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1719   Record.push_back(VE.getMetadataOrNullID(N->getDecl()));
1720   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1721   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1722   Record.push_back(N->getLineNo());
1723 
1724   Stream.EmitRecord(bitc::METADATA_COMMON_BLOCK, Record, Abbrev);
1725   Record.clear();
1726 }
1727 
1728 void ModuleBitcodeWriter::writeDINamespace(const DINamespace *N,
1729                                            SmallVectorImpl<uint64_t> &Record,
1730                                            unsigned Abbrev) {
1731   Record.push_back(N->isDistinct() | N->getExportSymbols() << 1);
1732   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1733   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1734 
1735   Stream.EmitRecord(bitc::METADATA_NAMESPACE, Record, Abbrev);
1736   Record.clear();
1737 }
1738 
1739 void ModuleBitcodeWriter::writeDIMacro(const DIMacro *N,
1740                                        SmallVectorImpl<uint64_t> &Record,
1741                                        unsigned Abbrev) {
1742   Record.push_back(N->isDistinct());
1743   Record.push_back(N->getMacinfoType());
1744   Record.push_back(N->getLine());
1745   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1746   Record.push_back(VE.getMetadataOrNullID(N->getRawValue()));
1747 
1748   Stream.EmitRecord(bitc::METADATA_MACRO, Record, Abbrev);
1749   Record.clear();
1750 }
1751 
1752 void ModuleBitcodeWriter::writeDIMacroFile(const DIMacroFile *N,
1753                                            SmallVectorImpl<uint64_t> &Record,
1754                                            unsigned Abbrev) {
1755   Record.push_back(N->isDistinct());
1756   Record.push_back(N->getMacinfoType());
1757   Record.push_back(N->getLine());
1758   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1759   Record.push_back(VE.getMetadataOrNullID(N->getElements().get()));
1760 
1761   Stream.EmitRecord(bitc::METADATA_MACRO_FILE, Record, Abbrev);
1762   Record.clear();
1763 }
1764 
1765 void ModuleBitcodeWriter::writeDIModule(const DIModule *N,
1766                                         SmallVectorImpl<uint64_t> &Record,
1767                                         unsigned Abbrev) {
1768   Record.push_back(N->isDistinct());
1769   for (auto &I : N->operands())
1770     Record.push_back(VE.getMetadataOrNullID(I));
1771 
1772   Stream.EmitRecord(bitc::METADATA_MODULE, Record, Abbrev);
1773   Record.clear();
1774 }
1775 
1776 void ModuleBitcodeWriter::writeDITemplateTypeParameter(
1777     const DITemplateTypeParameter *N, SmallVectorImpl<uint64_t> &Record,
1778     unsigned Abbrev) {
1779   Record.push_back(N->isDistinct());
1780   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1781   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1782 
1783   Stream.EmitRecord(bitc::METADATA_TEMPLATE_TYPE, Record, Abbrev);
1784   Record.clear();
1785 }
1786 
1787 void ModuleBitcodeWriter::writeDITemplateValueParameter(
1788     const DITemplateValueParameter *N, SmallVectorImpl<uint64_t> &Record,
1789     unsigned Abbrev) {
1790   Record.push_back(N->isDistinct());
1791   Record.push_back(N->getTag());
1792   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1793   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1794   Record.push_back(VE.getMetadataOrNullID(N->getValue()));
1795 
1796   Stream.EmitRecord(bitc::METADATA_TEMPLATE_VALUE, Record, Abbrev);
1797   Record.clear();
1798 }
1799 
1800 void ModuleBitcodeWriter::writeDIGlobalVariable(
1801     const DIGlobalVariable *N, SmallVectorImpl<uint64_t> &Record,
1802     unsigned Abbrev) {
1803   const uint64_t Version = 2 << 1;
1804   Record.push_back((uint64_t)N->isDistinct() | Version);
1805   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1806   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1807   Record.push_back(VE.getMetadataOrNullID(N->getRawLinkageName()));
1808   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1809   Record.push_back(N->getLine());
1810   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1811   Record.push_back(N->isLocalToUnit());
1812   Record.push_back(N->isDefinition());
1813   Record.push_back(VE.getMetadataOrNullID(N->getStaticDataMemberDeclaration()));
1814   Record.push_back(VE.getMetadataOrNullID(N->getTemplateParams()));
1815   Record.push_back(N->getAlignInBits());
1816 
1817   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR, Record, Abbrev);
1818   Record.clear();
1819 }
1820 
1821 void ModuleBitcodeWriter::writeDILocalVariable(
1822     const DILocalVariable *N, SmallVectorImpl<uint64_t> &Record,
1823     unsigned Abbrev) {
1824   // In order to support all possible bitcode formats in BitcodeReader we need
1825   // to distinguish the following cases:
1826   // 1) Record has no artificial tag (Record[1]),
1827   //   has no obsolete inlinedAt field (Record[9]).
1828   //   In this case Record size will be 8, HasAlignment flag is false.
1829   // 2) Record has artificial tag (Record[1]),
1830   //   has no obsolete inlignedAt field (Record[9]).
1831   //   In this case Record size will be 9, HasAlignment flag is false.
1832   // 3) Record has both artificial tag (Record[1]) and
1833   //   obsolete inlignedAt field (Record[9]).
1834   //   In this case Record size will be 10, HasAlignment flag is false.
1835   // 4) Record has neither artificial tag, nor inlignedAt field, but
1836   //   HasAlignment flag is true and Record[8] contains alignment value.
1837   const uint64_t HasAlignmentFlag = 1 << 1;
1838   Record.push_back((uint64_t)N->isDistinct() | HasAlignmentFlag);
1839   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1840   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1841   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1842   Record.push_back(N->getLine());
1843   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1844   Record.push_back(N->getArg());
1845   Record.push_back(N->getFlags());
1846   Record.push_back(N->getAlignInBits());
1847 
1848   Stream.EmitRecord(bitc::METADATA_LOCAL_VAR, Record, Abbrev);
1849   Record.clear();
1850 }
1851 
1852 void ModuleBitcodeWriter::writeDILabel(
1853     const DILabel *N, SmallVectorImpl<uint64_t> &Record,
1854     unsigned Abbrev) {
1855   Record.push_back((uint64_t)N->isDistinct());
1856   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1857   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1858   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1859   Record.push_back(N->getLine());
1860 
1861   Stream.EmitRecord(bitc::METADATA_LABEL, Record, Abbrev);
1862   Record.clear();
1863 }
1864 
1865 void ModuleBitcodeWriter::writeDIExpression(const DIExpression *N,
1866                                             SmallVectorImpl<uint64_t> &Record,
1867                                             unsigned Abbrev) {
1868   Record.reserve(N->getElements().size() + 1);
1869   const uint64_t Version = 3 << 1;
1870   Record.push_back((uint64_t)N->isDistinct() | Version);
1871   Record.append(N->elements_begin(), N->elements_end());
1872 
1873   Stream.EmitRecord(bitc::METADATA_EXPRESSION, Record, Abbrev);
1874   Record.clear();
1875 }
1876 
1877 void ModuleBitcodeWriter::writeDIGlobalVariableExpression(
1878     const DIGlobalVariableExpression *N, SmallVectorImpl<uint64_t> &Record,
1879     unsigned Abbrev) {
1880   Record.push_back(N->isDistinct());
1881   Record.push_back(VE.getMetadataOrNullID(N->getVariable()));
1882   Record.push_back(VE.getMetadataOrNullID(N->getExpression()));
1883 
1884   Stream.EmitRecord(bitc::METADATA_GLOBAL_VAR_EXPR, Record, Abbrev);
1885   Record.clear();
1886 }
1887 
1888 void ModuleBitcodeWriter::writeDIObjCProperty(const DIObjCProperty *N,
1889                                               SmallVectorImpl<uint64_t> &Record,
1890                                               unsigned Abbrev) {
1891   Record.push_back(N->isDistinct());
1892   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1893   Record.push_back(VE.getMetadataOrNullID(N->getFile()));
1894   Record.push_back(N->getLine());
1895   Record.push_back(VE.getMetadataOrNullID(N->getRawSetterName()));
1896   Record.push_back(VE.getMetadataOrNullID(N->getRawGetterName()));
1897   Record.push_back(N->getAttributes());
1898   Record.push_back(VE.getMetadataOrNullID(N->getType()));
1899 
1900   Stream.EmitRecord(bitc::METADATA_OBJC_PROPERTY, Record, Abbrev);
1901   Record.clear();
1902 }
1903 
1904 void ModuleBitcodeWriter::writeDIImportedEntity(
1905     const DIImportedEntity *N, SmallVectorImpl<uint64_t> &Record,
1906     unsigned Abbrev) {
1907   Record.push_back(N->isDistinct());
1908   Record.push_back(N->getTag());
1909   Record.push_back(VE.getMetadataOrNullID(N->getScope()));
1910   Record.push_back(VE.getMetadataOrNullID(N->getEntity()));
1911   Record.push_back(N->getLine());
1912   Record.push_back(VE.getMetadataOrNullID(N->getRawName()));
1913   Record.push_back(VE.getMetadataOrNullID(N->getRawFile()));
1914 
1915   Stream.EmitRecord(bitc::METADATA_IMPORTED_ENTITY, Record, Abbrev);
1916   Record.clear();
1917 }
1918 
1919 unsigned ModuleBitcodeWriter::createNamedMetadataAbbrev() {
1920   auto Abbv = std::make_shared<BitCodeAbbrev>();
1921   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_NAME));
1922   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
1923   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
1924   return Stream.EmitAbbrev(std::move(Abbv));
1925 }
1926 
1927 void ModuleBitcodeWriter::writeNamedMetadata(
1928     SmallVectorImpl<uint64_t> &Record) {
1929   if (M.named_metadata_empty())
1930     return;
1931 
1932   unsigned Abbrev = createNamedMetadataAbbrev();
1933   for (const NamedMDNode &NMD : M.named_metadata()) {
1934     // Write name.
1935     StringRef Str = NMD.getName();
1936     Record.append(Str.bytes_begin(), Str.bytes_end());
1937     Stream.EmitRecord(bitc::METADATA_NAME, Record, Abbrev);
1938     Record.clear();
1939 
1940     // Write named metadata operands.
1941     for (const MDNode *N : NMD.operands())
1942       Record.push_back(VE.getMetadataID(N));
1943     Stream.EmitRecord(bitc::METADATA_NAMED_NODE, Record, 0);
1944     Record.clear();
1945   }
1946 }
1947 
1948 unsigned ModuleBitcodeWriter::createMetadataStringsAbbrev() {
1949   auto Abbv = std::make_shared<BitCodeAbbrev>();
1950   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_STRINGS));
1951   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // # of strings
1952   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // offset to chars
1953   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
1954   return Stream.EmitAbbrev(std::move(Abbv));
1955 }
1956 
1957 /// Write out a record for MDString.
1958 ///
1959 /// All the metadata strings in a metadata block are emitted in a single
1960 /// record.  The sizes and strings themselves are shoved into a blob.
1961 void ModuleBitcodeWriter::writeMetadataStrings(
1962     ArrayRef<const Metadata *> Strings, SmallVectorImpl<uint64_t> &Record) {
1963   if (Strings.empty())
1964     return;
1965 
1966   // Start the record with the number of strings.
1967   Record.push_back(bitc::METADATA_STRINGS);
1968   Record.push_back(Strings.size());
1969 
1970   // Emit the sizes of the strings in the blob.
1971   SmallString<256> Blob;
1972   {
1973     BitstreamWriter W(Blob);
1974     for (const Metadata *MD : Strings)
1975       W.EmitVBR(cast<MDString>(MD)->getLength(), 6);
1976     W.FlushToWord();
1977   }
1978 
1979   // Add the offset to the strings to the record.
1980   Record.push_back(Blob.size());
1981 
1982   // Add the strings to the blob.
1983   for (const Metadata *MD : Strings)
1984     Blob.append(cast<MDString>(MD)->getString());
1985 
1986   // Emit the final record.
1987   Stream.EmitRecordWithBlob(createMetadataStringsAbbrev(), Record, Blob);
1988   Record.clear();
1989 }
1990 
1991 // Generates an enum to use as an index in the Abbrev array of Metadata record.
1992 enum MetadataAbbrev : unsigned {
1993 #define HANDLE_MDNODE_LEAF(CLASS) CLASS##AbbrevID,
1994 #include "llvm/IR/Metadata.def"
1995   LastPlusOne
1996 };
1997 
1998 void ModuleBitcodeWriter::writeMetadataRecords(
1999     ArrayRef<const Metadata *> MDs, SmallVectorImpl<uint64_t> &Record,
2000     std::vector<unsigned> *MDAbbrevs, std::vector<uint64_t> *IndexPos) {
2001   if (MDs.empty())
2002     return;
2003 
2004   // Initialize MDNode abbreviations.
2005 #define HANDLE_MDNODE_LEAF(CLASS) unsigned CLASS##Abbrev = 0;
2006 #include "llvm/IR/Metadata.def"
2007 
2008   for (const Metadata *MD : MDs) {
2009     if (IndexPos)
2010       IndexPos->push_back(Stream.GetCurrentBitNo());
2011     if (const MDNode *N = dyn_cast<MDNode>(MD)) {
2012       assert(N->isResolved() && "Expected forward references to be resolved");
2013 
2014       switch (N->getMetadataID()) {
2015       default:
2016         llvm_unreachable("Invalid MDNode subclass");
2017 #define HANDLE_MDNODE_LEAF(CLASS)                                              \
2018   case Metadata::CLASS##Kind:                                                  \
2019     if (MDAbbrevs)                                                             \
2020       write##CLASS(cast<CLASS>(N), Record,                                     \
2021                    (*MDAbbrevs)[MetadataAbbrev::CLASS##AbbrevID]);             \
2022     else                                                                       \
2023       write##CLASS(cast<CLASS>(N), Record, CLASS##Abbrev);                     \
2024     continue;
2025 #include "llvm/IR/Metadata.def"
2026       }
2027     }
2028     writeValueAsMetadata(cast<ValueAsMetadata>(MD), Record);
2029   }
2030 }
2031 
2032 void ModuleBitcodeWriter::writeModuleMetadata() {
2033   if (!VE.hasMDs() && M.named_metadata_empty())
2034     return;
2035 
2036   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 4);
2037   SmallVector<uint64_t, 64> Record;
2038 
2039   // Emit all abbrevs upfront, so that the reader can jump in the middle of the
2040   // block and load any metadata.
2041   std::vector<unsigned> MDAbbrevs;
2042 
2043   MDAbbrevs.resize(MetadataAbbrev::LastPlusOne);
2044   MDAbbrevs[MetadataAbbrev::DILocationAbbrevID] = createDILocationAbbrev();
2045   MDAbbrevs[MetadataAbbrev::GenericDINodeAbbrevID] =
2046       createGenericDINodeAbbrev();
2047 
2048   auto Abbv = std::make_shared<BitCodeAbbrev>();
2049   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX_OFFSET));
2050   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2051   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
2052   unsigned OffsetAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2053 
2054   Abbv = std::make_shared<BitCodeAbbrev>();
2055   Abbv->Add(BitCodeAbbrevOp(bitc::METADATA_INDEX));
2056   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2057   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
2058   unsigned IndexAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2059 
2060   // Emit MDStrings together upfront.
2061   writeMetadataStrings(VE.getMDStrings(), Record);
2062 
2063   // We only emit an index for the metadata record if we have more than a given
2064   // (naive) threshold of metadatas, otherwise it is not worth it.
2065   if (VE.getNonMDStrings().size() > IndexThreshold) {
2066     // Write a placeholder value in for the offset of the metadata index,
2067     // which is written after the records, so that it can include
2068     // the offset of each entry. The placeholder offset will be
2069     // updated after all records are emitted.
2070     uint64_t Vals[] = {0, 0};
2071     Stream.EmitRecord(bitc::METADATA_INDEX_OFFSET, Vals, OffsetAbbrev);
2072   }
2073 
2074   // Compute and save the bit offset to the current position, which will be
2075   // patched when we emit the index later. We can simply subtract the 64-bit
2076   // fixed size from the current bit number to get the location to backpatch.
2077   uint64_t IndexOffsetRecordBitPos = Stream.GetCurrentBitNo();
2078 
2079   // This index will contain the bitpos for each individual record.
2080   std::vector<uint64_t> IndexPos;
2081   IndexPos.reserve(VE.getNonMDStrings().size());
2082 
2083   // Write all the records
2084   writeMetadataRecords(VE.getNonMDStrings(), Record, &MDAbbrevs, &IndexPos);
2085 
2086   if (VE.getNonMDStrings().size() > IndexThreshold) {
2087     // Now that we have emitted all the records we will emit the index. But
2088     // first
2089     // backpatch the forward reference so that the reader can skip the records
2090     // efficiently.
2091     Stream.BackpatchWord64(IndexOffsetRecordBitPos - 64,
2092                            Stream.GetCurrentBitNo() - IndexOffsetRecordBitPos);
2093 
2094     // Delta encode the index.
2095     uint64_t PreviousValue = IndexOffsetRecordBitPos;
2096     for (auto &Elt : IndexPos) {
2097       auto EltDelta = Elt - PreviousValue;
2098       PreviousValue = Elt;
2099       Elt = EltDelta;
2100     }
2101     // Emit the index record.
2102     Stream.EmitRecord(bitc::METADATA_INDEX, IndexPos, IndexAbbrev);
2103     IndexPos.clear();
2104   }
2105 
2106   // Write the named metadata now.
2107   writeNamedMetadata(Record);
2108 
2109   auto AddDeclAttachedMetadata = [&](const GlobalObject &GO) {
2110     SmallVector<uint64_t, 4> Record;
2111     Record.push_back(VE.getValueID(&GO));
2112     pushGlobalMetadataAttachment(Record, GO);
2113     Stream.EmitRecord(bitc::METADATA_GLOBAL_DECL_ATTACHMENT, Record);
2114   };
2115   for (const Function &F : M)
2116     if (F.isDeclaration() && F.hasMetadata())
2117       AddDeclAttachedMetadata(F);
2118   // FIXME: Only store metadata for declarations here, and move data for global
2119   // variable definitions to a separate block (PR28134).
2120   for (const GlobalVariable &GV : M.globals())
2121     if (GV.hasMetadata())
2122       AddDeclAttachedMetadata(GV);
2123 
2124   Stream.ExitBlock();
2125 }
2126 
2127 void ModuleBitcodeWriter::writeFunctionMetadata(const Function &F) {
2128   if (!VE.hasMDs())
2129     return;
2130 
2131   Stream.EnterSubblock(bitc::METADATA_BLOCK_ID, 3);
2132   SmallVector<uint64_t, 64> Record;
2133   writeMetadataStrings(VE.getMDStrings(), Record);
2134   writeMetadataRecords(VE.getNonMDStrings(), Record);
2135   Stream.ExitBlock();
2136 }
2137 
2138 void ModuleBitcodeWriter::pushGlobalMetadataAttachment(
2139     SmallVectorImpl<uint64_t> &Record, const GlobalObject &GO) {
2140   // [n x [id, mdnode]]
2141   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2142   GO.getAllMetadata(MDs);
2143   for (const auto &I : MDs) {
2144     Record.push_back(I.first);
2145     Record.push_back(VE.getMetadataID(I.second));
2146   }
2147 }
2148 
2149 void ModuleBitcodeWriter::writeFunctionMetadataAttachment(const Function &F) {
2150   Stream.EnterSubblock(bitc::METADATA_ATTACHMENT_ID, 3);
2151 
2152   SmallVector<uint64_t, 64> Record;
2153 
2154   if (F.hasMetadata()) {
2155     pushGlobalMetadataAttachment(Record, F);
2156     Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2157     Record.clear();
2158   }
2159 
2160   // Write metadata attachments
2161   // METADATA_ATTACHMENT - [m x [value, [n x [id, mdnode]]]
2162   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
2163   for (const BasicBlock &BB : F)
2164     for (const Instruction &I : BB) {
2165       MDs.clear();
2166       I.getAllMetadataOtherThanDebugLoc(MDs);
2167 
2168       // If no metadata, ignore instruction.
2169       if (MDs.empty()) continue;
2170 
2171       Record.push_back(VE.getInstructionID(&I));
2172 
2173       for (unsigned i = 0, e = MDs.size(); i != e; ++i) {
2174         Record.push_back(MDs[i].first);
2175         Record.push_back(VE.getMetadataID(MDs[i].second));
2176       }
2177       Stream.EmitRecord(bitc::METADATA_ATTACHMENT, Record, 0);
2178       Record.clear();
2179     }
2180 
2181   Stream.ExitBlock();
2182 }
2183 
2184 void ModuleBitcodeWriter::writeModuleMetadataKinds() {
2185   SmallVector<uint64_t, 64> Record;
2186 
2187   // Write metadata kinds
2188   // METADATA_KIND - [n x [id, name]]
2189   SmallVector<StringRef, 8> Names;
2190   M.getMDKindNames(Names);
2191 
2192   if (Names.empty()) return;
2193 
2194   Stream.EnterSubblock(bitc::METADATA_KIND_BLOCK_ID, 3);
2195 
2196   for (unsigned MDKindID = 0, e = Names.size(); MDKindID != e; ++MDKindID) {
2197     Record.push_back(MDKindID);
2198     StringRef KName = Names[MDKindID];
2199     Record.append(KName.begin(), KName.end());
2200 
2201     Stream.EmitRecord(bitc::METADATA_KIND, Record, 0);
2202     Record.clear();
2203   }
2204 
2205   Stream.ExitBlock();
2206 }
2207 
2208 void ModuleBitcodeWriter::writeOperandBundleTags() {
2209   // Write metadata kinds
2210   //
2211   // OPERAND_BUNDLE_TAGS_BLOCK_ID : N x OPERAND_BUNDLE_TAG
2212   //
2213   // OPERAND_BUNDLE_TAG - [strchr x N]
2214 
2215   SmallVector<StringRef, 8> Tags;
2216   M.getOperandBundleTags(Tags);
2217 
2218   if (Tags.empty())
2219     return;
2220 
2221   Stream.EnterSubblock(bitc::OPERAND_BUNDLE_TAGS_BLOCK_ID, 3);
2222 
2223   SmallVector<uint64_t, 64> Record;
2224 
2225   for (auto Tag : Tags) {
2226     Record.append(Tag.begin(), Tag.end());
2227 
2228     Stream.EmitRecord(bitc::OPERAND_BUNDLE_TAG, Record, 0);
2229     Record.clear();
2230   }
2231 
2232   Stream.ExitBlock();
2233 }
2234 
2235 void ModuleBitcodeWriter::writeSyncScopeNames() {
2236   SmallVector<StringRef, 8> SSNs;
2237   M.getContext().getSyncScopeNames(SSNs);
2238   if (SSNs.empty())
2239     return;
2240 
2241   Stream.EnterSubblock(bitc::SYNC_SCOPE_NAMES_BLOCK_ID, 2);
2242 
2243   SmallVector<uint64_t, 64> Record;
2244   for (auto SSN : SSNs) {
2245     Record.append(SSN.begin(), SSN.end());
2246     Stream.EmitRecord(bitc::SYNC_SCOPE_NAME, Record, 0);
2247     Record.clear();
2248   }
2249 
2250   Stream.ExitBlock();
2251 }
2252 
2253 static void emitSignedInt64(SmallVectorImpl<uint64_t> &Vals, uint64_t V) {
2254   if ((int64_t)V >= 0)
2255     Vals.push_back(V << 1);
2256   else
2257     Vals.push_back((-V << 1) | 1);
2258 }
2259 
2260 void ModuleBitcodeWriter::writeConstants(unsigned FirstVal, unsigned LastVal,
2261                                          bool isGlobal) {
2262   if (FirstVal == LastVal) return;
2263 
2264   Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
2265 
2266   unsigned AggregateAbbrev = 0;
2267   unsigned String8Abbrev = 0;
2268   unsigned CString7Abbrev = 0;
2269   unsigned CString6Abbrev = 0;
2270   // If this is a constant pool for the module, emit module-specific abbrevs.
2271   if (isGlobal) {
2272     // Abbrev for CST_CODE_AGGREGATE.
2273     auto Abbv = std::make_shared<BitCodeAbbrev>();
2274     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_AGGREGATE));
2275     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2276     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
2277     AggregateAbbrev = Stream.EmitAbbrev(std::move(Abbv));
2278 
2279     // Abbrev for CST_CODE_STRING.
2280     Abbv = std::make_shared<BitCodeAbbrev>();
2281     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
2282     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2283     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
2284     String8Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2285     // Abbrev for CST_CODE_CSTRING.
2286     Abbv = std::make_shared<BitCodeAbbrev>();
2287     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2288     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2289     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
2290     CString7Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2291     // Abbrev for CST_CODE_CSTRING.
2292     Abbv = std::make_shared<BitCodeAbbrev>();
2293     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
2294     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
2295     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
2296     CString6Abbrev = Stream.EmitAbbrev(std::move(Abbv));
2297   }
2298 
2299   SmallVector<uint64_t, 64> Record;
2300 
2301   const ValueEnumerator::ValueList &Vals = VE.getValues();
2302   Type *LastTy = nullptr;
2303   for (unsigned i = FirstVal; i != LastVal; ++i) {
2304     const Value *V = Vals[i].first;
2305     // If we need to switch types, do so now.
2306     if (V->getType() != LastTy) {
2307       LastTy = V->getType();
2308       Record.push_back(VE.getTypeID(LastTy));
2309       Stream.EmitRecord(bitc::CST_CODE_SETTYPE, Record,
2310                         CONSTANTS_SETTYPE_ABBREV);
2311       Record.clear();
2312     }
2313 
2314     if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
2315       Record.push_back(unsigned(IA->hasSideEffects()) |
2316                        unsigned(IA->isAlignStack()) << 1 |
2317                        unsigned(IA->getDialect()&1) << 2);
2318 
2319       // Add the asm string.
2320       const std::string &AsmStr = IA->getAsmString();
2321       Record.push_back(AsmStr.size());
2322       Record.append(AsmStr.begin(), AsmStr.end());
2323 
2324       // Add the constraint string.
2325       const std::string &ConstraintStr = IA->getConstraintString();
2326       Record.push_back(ConstraintStr.size());
2327       Record.append(ConstraintStr.begin(), ConstraintStr.end());
2328       Stream.EmitRecord(bitc::CST_CODE_INLINEASM, Record);
2329       Record.clear();
2330       continue;
2331     }
2332     const Constant *C = cast<Constant>(V);
2333     unsigned Code = -1U;
2334     unsigned AbbrevToUse = 0;
2335     if (C->isNullValue()) {
2336       Code = bitc::CST_CODE_NULL;
2337     } else if (isa<UndefValue>(C)) {
2338       Code = bitc::CST_CODE_UNDEF;
2339     } else if (const ConstantInt *IV = dyn_cast<ConstantInt>(C)) {
2340       if (IV->getBitWidth() <= 64) {
2341         uint64_t V = IV->getSExtValue();
2342         emitSignedInt64(Record, V);
2343         Code = bitc::CST_CODE_INTEGER;
2344         AbbrevToUse = CONSTANTS_INTEGER_ABBREV;
2345       } else {                             // Wide integers, > 64 bits in size.
2346         // We have an arbitrary precision integer value to write whose
2347         // bit width is > 64. However, in canonical unsigned integer
2348         // format it is likely that the high bits are going to be zero.
2349         // So, we only write the number of active words.
2350         unsigned NWords = IV->getValue().getActiveWords();
2351         const uint64_t *RawWords = IV->getValue().getRawData();
2352         for (unsigned i = 0; i != NWords; ++i) {
2353           emitSignedInt64(Record, RawWords[i]);
2354         }
2355         Code = bitc::CST_CODE_WIDE_INTEGER;
2356       }
2357     } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
2358       Code = bitc::CST_CODE_FLOAT;
2359       Type *Ty = CFP->getType();
2360       if (Ty->isHalfTy() || Ty->isFloatTy() || Ty->isDoubleTy()) {
2361         Record.push_back(CFP->getValueAPF().bitcastToAPInt().getZExtValue());
2362       } else if (Ty->isX86_FP80Ty()) {
2363         // api needed to prevent premature destruction
2364         // bits are not in the same order as a normal i80 APInt, compensate.
2365         APInt api = CFP->getValueAPF().bitcastToAPInt();
2366         const uint64_t *p = api.getRawData();
2367         Record.push_back((p[1] << 48) | (p[0] >> 16));
2368         Record.push_back(p[0] & 0xffffLL);
2369       } else if (Ty->isFP128Ty() || Ty->isPPC_FP128Ty()) {
2370         APInt api = CFP->getValueAPF().bitcastToAPInt();
2371         const uint64_t *p = api.getRawData();
2372         Record.push_back(p[0]);
2373         Record.push_back(p[1]);
2374       } else {
2375         assert(0 && "Unknown FP type!");
2376       }
2377     } else if (isa<ConstantDataSequential>(C) &&
2378                cast<ConstantDataSequential>(C)->isString()) {
2379       const ConstantDataSequential *Str = cast<ConstantDataSequential>(C);
2380       // Emit constant strings specially.
2381       unsigned NumElts = Str->getNumElements();
2382       // If this is a null-terminated string, use the denser CSTRING encoding.
2383       if (Str->isCString()) {
2384         Code = bitc::CST_CODE_CSTRING;
2385         --NumElts;  // Don't encode the null, which isn't allowed by char6.
2386       } else {
2387         Code = bitc::CST_CODE_STRING;
2388         AbbrevToUse = String8Abbrev;
2389       }
2390       bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
2391       bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
2392       for (unsigned i = 0; i != NumElts; ++i) {
2393         unsigned char V = Str->getElementAsInteger(i);
2394         Record.push_back(V);
2395         isCStr7 &= (V & 128) == 0;
2396         if (isCStrChar6)
2397           isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
2398       }
2399 
2400       if (isCStrChar6)
2401         AbbrevToUse = CString6Abbrev;
2402       else if (isCStr7)
2403         AbbrevToUse = CString7Abbrev;
2404     } else if (const ConstantDataSequential *CDS =
2405                   dyn_cast<ConstantDataSequential>(C)) {
2406       Code = bitc::CST_CODE_DATA;
2407       Type *EltTy = CDS->getType()->getElementType();
2408       if (isa<IntegerType>(EltTy)) {
2409         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2410           Record.push_back(CDS->getElementAsInteger(i));
2411       } else {
2412         for (unsigned i = 0, e = CDS->getNumElements(); i != e; ++i)
2413           Record.push_back(
2414               CDS->getElementAsAPFloat(i).bitcastToAPInt().getLimitedValue());
2415       }
2416     } else if (isa<ConstantAggregate>(C)) {
2417       Code = bitc::CST_CODE_AGGREGATE;
2418       for (const Value *Op : C->operands())
2419         Record.push_back(VE.getValueID(Op));
2420       AbbrevToUse = AggregateAbbrev;
2421     } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
2422       switch (CE->getOpcode()) {
2423       default:
2424         if (Instruction::isCast(CE->getOpcode())) {
2425           Code = bitc::CST_CODE_CE_CAST;
2426           Record.push_back(getEncodedCastOpcode(CE->getOpcode()));
2427           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2428           Record.push_back(VE.getValueID(C->getOperand(0)));
2429           AbbrevToUse = CONSTANTS_CE_CAST_Abbrev;
2430         } else {
2431           assert(CE->getNumOperands() == 2 && "Unknown constant expr!");
2432           Code = bitc::CST_CODE_CE_BINOP;
2433           Record.push_back(getEncodedBinaryOpcode(CE->getOpcode()));
2434           Record.push_back(VE.getValueID(C->getOperand(0)));
2435           Record.push_back(VE.getValueID(C->getOperand(1)));
2436           uint64_t Flags = getOptimizationFlags(CE);
2437           if (Flags != 0)
2438             Record.push_back(Flags);
2439         }
2440         break;
2441       case Instruction::FNeg: {
2442         assert(CE->getNumOperands() == 1 && "Unknown constant expr!");
2443         Code = bitc::CST_CODE_CE_UNOP;
2444         Record.push_back(getEncodedUnaryOpcode(CE->getOpcode()));
2445         Record.push_back(VE.getValueID(C->getOperand(0)));
2446         uint64_t Flags = getOptimizationFlags(CE);
2447         if (Flags != 0)
2448           Record.push_back(Flags);
2449         break;
2450       }
2451       case Instruction::GetElementPtr: {
2452         Code = bitc::CST_CODE_CE_GEP;
2453         const auto *GO = cast<GEPOperator>(C);
2454         Record.push_back(VE.getTypeID(GO->getSourceElementType()));
2455         if (Optional<unsigned> Idx = GO->getInRangeIndex()) {
2456           Code = bitc::CST_CODE_CE_GEP_WITH_INRANGE_INDEX;
2457           Record.push_back((*Idx << 1) | GO->isInBounds());
2458         } else if (GO->isInBounds())
2459           Code = bitc::CST_CODE_CE_INBOUNDS_GEP;
2460         for (unsigned i = 0, e = CE->getNumOperands(); i != e; ++i) {
2461           Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
2462           Record.push_back(VE.getValueID(C->getOperand(i)));
2463         }
2464         break;
2465       }
2466       case Instruction::Select:
2467         Code = bitc::CST_CODE_CE_SELECT;
2468         Record.push_back(VE.getValueID(C->getOperand(0)));
2469         Record.push_back(VE.getValueID(C->getOperand(1)));
2470         Record.push_back(VE.getValueID(C->getOperand(2)));
2471         break;
2472       case Instruction::ExtractElement:
2473         Code = bitc::CST_CODE_CE_EXTRACTELT;
2474         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2475         Record.push_back(VE.getValueID(C->getOperand(0)));
2476         Record.push_back(VE.getTypeID(C->getOperand(1)->getType()));
2477         Record.push_back(VE.getValueID(C->getOperand(1)));
2478         break;
2479       case Instruction::InsertElement:
2480         Code = bitc::CST_CODE_CE_INSERTELT;
2481         Record.push_back(VE.getValueID(C->getOperand(0)));
2482         Record.push_back(VE.getValueID(C->getOperand(1)));
2483         Record.push_back(VE.getTypeID(C->getOperand(2)->getType()));
2484         Record.push_back(VE.getValueID(C->getOperand(2)));
2485         break;
2486       case Instruction::ShuffleVector:
2487         // If the return type and argument types are the same, this is a
2488         // standard shufflevector instruction.  If the types are different,
2489         // then the shuffle is widening or truncating the input vectors, and
2490         // the argument type must also be encoded.
2491         if (C->getType() == C->getOperand(0)->getType()) {
2492           Code = bitc::CST_CODE_CE_SHUFFLEVEC;
2493         } else {
2494           Code = bitc::CST_CODE_CE_SHUFVEC_EX;
2495           Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2496         }
2497         Record.push_back(VE.getValueID(C->getOperand(0)));
2498         Record.push_back(VE.getValueID(C->getOperand(1)));
2499         Record.push_back(VE.getValueID(C->getOperand(2)));
2500         break;
2501       case Instruction::ICmp:
2502       case Instruction::FCmp:
2503         Code = bitc::CST_CODE_CE_CMP;
2504         Record.push_back(VE.getTypeID(C->getOperand(0)->getType()));
2505         Record.push_back(VE.getValueID(C->getOperand(0)));
2506         Record.push_back(VE.getValueID(C->getOperand(1)));
2507         Record.push_back(CE->getPredicate());
2508         break;
2509       }
2510     } else if (const BlockAddress *BA = dyn_cast<BlockAddress>(C)) {
2511       Code = bitc::CST_CODE_BLOCKADDRESS;
2512       Record.push_back(VE.getTypeID(BA->getFunction()->getType()));
2513       Record.push_back(VE.getValueID(BA->getFunction()));
2514       Record.push_back(VE.getGlobalBasicBlockID(BA->getBasicBlock()));
2515     } else {
2516 #ifndef NDEBUG
2517       C->dump();
2518 #endif
2519       llvm_unreachable("Unknown constant!");
2520     }
2521     Stream.EmitRecord(Code, Record, AbbrevToUse);
2522     Record.clear();
2523   }
2524 
2525   Stream.ExitBlock();
2526 }
2527 
2528 void ModuleBitcodeWriter::writeModuleConstants() {
2529   const ValueEnumerator::ValueList &Vals = VE.getValues();
2530 
2531   // Find the first constant to emit, which is the first non-globalvalue value.
2532   // We know globalvalues have been emitted by WriteModuleInfo.
2533   for (unsigned i = 0, e = Vals.size(); i != e; ++i) {
2534     if (!isa<GlobalValue>(Vals[i].first)) {
2535       writeConstants(i, Vals.size(), true);
2536       return;
2537     }
2538   }
2539 }
2540 
2541 /// pushValueAndType - The file has to encode both the value and type id for
2542 /// many values, because we need to know what type to create for forward
2543 /// references.  However, most operands are not forward references, so this type
2544 /// field is not needed.
2545 ///
2546 /// This function adds V's value ID to Vals.  If the value ID is higher than the
2547 /// instruction ID, then it is a forward reference, and it also includes the
2548 /// type ID.  The value ID that is written is encoded relative to the InstID.
2549 bool ModuleBitcodeWriter::pushValueAndType(const Value *V, unsigned InstID,
2550                                            SmallVectorImpl<unsigned> &Vals) {
2551   unsigned ValID = VE.getValueID(V);
2552   // Make encoding relative to the InstID.
2553   Vals.push_back(InstID - ValID);
2554   if (ValID >= InstID) {
2555     Vals.push_back(VE.getTypeID(V->getType()));
2556     return true;
2557   }
2558   return false;
2559 }
2560 
2561 void ModuleBitcodeWriter::writeOperandBundles(ImmutableCallSite CS,
2562                                               unsigned InstID) {
2563   SmallVector<unsigned, 64> Record;
2564   LLVMContext &C = CS.getInstruction()->getContext();
2565 
2566   for (unsigned i = 0, e = CS.getNumOperandBundles(); i != e; ++i) {
2567     const auto &Bundle = CS.getOperandBundleAt(i);
2568     Record.push_back(C.getOperandBundleTagID(Bundle.getTagName()));
2569 
2570     for (auto &Input : Bundle.Inputs)
2571       pushValueAndType(Input, InstID, Record);
2572 
2573     Stream.EmitRecord(bitc::FUNC_CODE_OPERAND_BUNDLE, Record);
2574     Record.clear();
2575   }
2576 }
2577 
2578 /// pushValue - Like pushValueAndType, but where the type of the value is
2579 /// omitted (perhaps it was already encoded in an earlier operand).
2580 void ModuleBitcodeWriter::pushValue(const Value *V, unsigned InstID,
2581                                     SmallVectorImpl<unsigned> &Vals) {
2582   unsigned ValID = VE.getValueID(V);
2583   Vals.push_back(InstID - ValID);
2584 }
2585 
2586 void ModuleBitcodeWriter::pushValueSigned(const Value *V, unsigned InstID,
2587                                           SmallVectorImpl<uint64_t> &Vals) {
2588   unsigned ValID = VE.getValueID(V);
2589   int64_t diff = ((int32_t)InstID - (int32_t)ValID);
2590   emitSignedInt64(Vals, diff);
2591 }
2592 
2593 /// WriteInstruction - Emit an instruction to the specified stream.
2594 void ModuleBitcodeWriter::writeInstruction(const Instruction &I,
2595                                            unsigned InstID,
2596                                            SmallVectorImpl<unsigned> &Vals) {
2597   unsigned Code = 0;
2598   unsigned AbbrevToUse = 0;
2599   VE.setInstructionID(&I);
2600   switch (I.getOpcode()) {
2601   default:
2602     if (Instruction::isCast(I.getOpcode())) {
2603       Code = bitc::FUNC_CODE_INST_CAST;
2604       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2605         AbbrevToUse = FUNCTION_INST_CAST_ABBREV;
2606       Vals.push_back(VE.getTypeID(I.getType()));
2607       Vals.push_back(getEncodedCastOpcode(I.getOpcode()));
2608     } else {
2609       assert(isa<BinaryOperator>(I) && "Unknown instruction!");
2610       Code = bitc::FUNC_CODE_INST_BINOP;
2611       if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2612         AbbrevToUse = FUNCTION_INST_BINOP_ABBREV;
2613       pushValue(I.getOperand(1), InstID, Vals);
2614       Vals.push_back(getEncodedBinaryOpcode(I.getOpcode()));
2615       uint64_t Flags = getOptimizationFlags(&I);
2616       if (Flags != 0) {
2617         if (AbbrevToUse == FUNCTION_INST_BINOP_ABBREV)
2618           AbbrevToUse = FUNCTION_INST_BINOP_FLAGS_ABBREV;
2619         Vals.push_back(Flags);
2620       }
2621     }
2622     break;
2623   case Instruction::FNeg: {
2624     Code = bitc::FUNC_CODE_INST_UNOP;
2625     if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2626       AbbrevToUse = FUNCTION_INST_UNOP_ABBREV;
2627     Vals.push_back(getEncodedUnaryOpcode(I.getOpcode()));
2628     uint64_t Flags = getOptimizationFlags(&I);
2629     if (Flags != 0) {
2630       if (AbbrevToUse == FUNCTION_INST_UNOP_ABBREV)
2631         AbbrevToUse = FUNCTION_INST_UNOP_FLAGS_ABBREV;
2632       Vals.push_back(Flags);
2633     }
2634     break;
2635   }
2636   case Instruction::GetElementPtr: {
2637     Code = bitc::FUNC_CODE_INST_GEP;
2638     AbbrevToUse = FUNCTION_INST_GEP_ABBREV;
2639     auto &GEPInst = cast<GetElementPtrInst>(I);
2640     Vals.push_back(GEPInst.isInBounds());
2641     Vals.push_back(VE.getTypeID(GEPInst.getSourceElementType()));
2642     for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
2643       pushValueAndType(I.getOperand(i), InstID, Vals);
2644     break;
2645   }
2646   case Instruction::ExtractValue: {
2647     Code = bitc::FUNC_CODE_INST_EXTRACTVAL;
2648     pushValueAndType(I.getOperand(0), InstID, Vals);
2649     const ExtractValueInst *EVI = cast<ExtractValueInst>(&I);
2650     Vals.append(EVI->idx_begin(), EVI->idx_end());
2651     break;
2652   }
2653   case Instruction::InsertValue: {
2654     Code = bitc::FUNC_CODE_INST_INSERTVAL;
2655     pushValueAndType(I.getOperand(0), InstID, Vals);
2656     pushValueAndType(I.getOperand(1), InstID, Vals);
2657     const InsertValueInst *IVI = cast<InsertValueInst>(&I);
2658     Vals.append(IVI->idx_begin(), IVI->idx_end());
2659     break;
2660   }
2661   case Instruction::Select: {
2662     Code = bitc::FUNC_CODE_INST_VSELECT;
2663     pushValueAndType(I.getOperand(1), InstID, Vals);
2664     pushValue(I.getOperand(2), InstID, Vals);
2665     pushValueAndType(I.getOperand(0), InstID, Vals);
2666     uint64_t Flags = getOptimizationFlags(&I);
2667     if (Flags != 0)
2668       Vals.push_back(Flags);
2669     break;
2670   }
2671   case Instruction::ExtractElement:
2672     Code = bitc::FUNC_CODE_INST_EXTRACTELT;
2673     pushValueAndType(I.getOperand(0), InstID, Vals);
2674     pushValueAndType(I.getOperand(1), InstID, Vals);
2675     break;
2676   case Instruction::InsertElement:
2677     Code = bitc::FUNC_CODE_INST_INSERTELT;
2678     pushValueAndType(I.getOperand(0), InstID, Vals);
2679     pushValue(I.getOperand(1), InstID, Vals);
2680     pushValueAndType(I.getOperand(2), InstID, Vals);
2681     break;
2682   case Instruction::ShuffleVector:
2683     Code = bitc::FUNC_CODE_INST_SHUFFLEVEC;
2684     pushValueAndType(I.getOperand(0), InstID, Vals);
2685     pushValue(I.getOperand(1), InstID, Vals);
2686     pushValue(I.getOperand(2), InstID, Vals);
2687     break;
2688   case Instruction::ICmp:
2689   case Instruction::FCmp: {
2690     // compare returning Int1Ty or vector of Int1Ty
2691     Code = bitc::FUNC_CODE_INST_CMP2;
2692     pushValueAndType(I.getOperand(0), InstID, Vals);
2693     pushValue(I.getOperand(1), InstID, Vals);
2694     Vals.push_back(cast<CmpInst>(I).getPredicate());
2695     uint64_t Flags = getOptimizationFlags(&I);
2696     if (Flags != 0)
2697       Vals.push_back(Flags);
2698     break;
2699   }
2700 
2701   case Instruction::Ret:
2702     {
2703       Code = bitc::FUNC_CODE_INST_RET;
2704       unsigned NumOperands = I.getNumOperands();
2705       if (NumOperands == 0)
2706         AbbrevToUse = FUNCTION_INST_RET_VOID_ABBREV;
2707       else if (NumOperands == 1) {
2708         if (!pushValueAndType(I.getOperand(0), InstID, Vals))
2709           AbbrevToUse = FUNCTION_INST_RET_VAL_ABBREV;
2710       } else {
2711         for (unsigned i = 0, e = NumOperands; i != e; ++i)
2712           pushValueAndType(I.getOperand(i), InstID, Vals);
2713       }
2714     }
2715     break;
2716   case Instruction::Br:
2717     {
2718       Code = bitc::FUNC_CODE_INST_BR;
2719       const BranchInst &II = cast<BranchInst>(I);
2720       Vals.push_back(VE.getValueID(II.getSuccessor(0)));
2721       if (II.isConditional()) {
2722         Vals.push_back(VE.getValueID(II.getSuccessor(1)));
2723         pushValue(II.getCondition(), InstID, Vals);
2724       }
2725     }
2726     break;
2727   case Instruction::Switch:
2728     {
2729       Code = bitc::FUNC_CODE_INST_SWITCH;
2730       const SwitchInst &SI = cast<SwitchInst>(I);
2731       Vals.push_back(VE.getTypeID(SI.getCondition()->getType()));
2732       pushValue(SI.getCondition(), InstID, Vals);
2733       Vals.push_back(VE.getValueID(SI.getDefaultDest()));
2734       for (auto Case : SI.cases()) {
2735         Vals.push_back(VE.getValueID(Case.getCaseValue()));
2736         Vals.push_back(VE.getValueID(Case.getCaseSuccessor()));
2737       }
2738     }
2739     break;
2740   case Instruction::IndirectBr:
2741     Code = bitc::FUNC_CODE_INST_INDIRECTBR;
2742     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2743     // Encode the address operand as relative, but not the basic blocks.
2744     pushValue(I.getOperand(0), InstID, Vals);
2745     for (unsigned i = 1, e = I.getNumOperands(); i != e; ++i)
2746       Vals.push_back(VE.getValueID(I.getOperand(i)));
2747     break;
2748 
2749   case Instruction::Invoke: {
2750     const InvokeInst *II = cast<InvokeInst>(&I);
2751     const Value *Callee = II->getCalledValue();
2752     FunctionType *FTy = II->getFunctionType();
2753 
2754     if (II->hasOperandBundles())
2755       writeOperandBundles(II, InstID);
2756 
2757     Code = bitc::FUNC_CODE_INST_INVOKE;
2758 
2759     Vals.push_back(VE.getAttributeListID(II->getAttributes()));
2760     Vals.push_back(II->getCallingConv() | 1 << 13);
2761     Vals.push_back(VE.getValueID(II->getNormalDest()));
2762     Vals.push_back(VE.getValueID(II->getUnwindDest()));
2763     Vals.push_back(VE.getTypeID(FTy));
2764     pushValueAndType(Callee, InstID, Vals);
2765 
2766     // Emit value #'s for the fixed parameters.
2767     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
2768       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
2769 
2770     // Emit type/value pairs for varargs params.
2771     if (FTy->isVarArg()) {
2772       for (unsigned i = FTy->getNumParams(), e = II->getNumArgOperands();
2773            i != e; ++i)
2774         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
2775     }
2776     break;
2777   }
2778   case Instruction::Resume:
2779     Code = bitc::FUNC_CODE_INST_RESUME;
2780     pushValueAndType(I.getOperand(0), InstID, Vals);
2781     break;
2782   case Instruction::CleanupRet: {
2783     Code = bitc::FUNC_CODE_INST_CLEANUPRET;
2784     const auto &CRI = cast<CleanupReturnInst>(I);
2785     pushValue(CRI.getCleanupPad(), InstID, Vals);
2786     if (CRI.hasUnwindDest())
2787       Vals.push_back(VE.getValueID(CRI.getUnwindDest()));
2788     break;
2789   }
2790   case Instruction::CatchRet: {
2791     Code = bitc::FUNC_CODE_INST_CATCHRET;
2792     const auto &CRI = cast<CatchReturnInst>(I);
2793     pushValue(CRI.getCatchPad(), InstID, Vals);
2794     Vals.push_back(VE.getValueID(CRI.getSuccessor()));
2795     break;
2796   }
2797   case Instruction::CleanupPad:
2798   case Instruction::CatchPad: {
2799     const auto &FuncletPad = cast<FuncletPadInst>(I);
2800     Code = isa<CatchPadInst>(FuncletPad) ? bitc::FUNC_CODE_INST_CATCHPAD
2801                                          : bitc::FUNC_CODE_INST_CLEANUPPAD;
2802     pushValue(FuncletPad.getParentPad(), InstID, Vals);
2803 
2804     unsigned NumArgOperands = FuncletPad.getNumArgOperands();
2805     Vals.push_back(NumArgOperands);
2806     for (unsigned Op = 0; Op != NumArgOperands; ++Op)
2807       pushValueAndType(FuncletPad.getArgOperand(Op), InstID, Vals);
2808     break;
2809   }
2810   case Instruction::CatchSwitch: {
2811     Code = bitc::FUNC_CODE_INST_CATCHSWITCH;
2812     const auto &CatchSwitch = cast<CatchSwitchInst>(I);
2813 
2814     pushValue(CatchSwitch.getParentPad(), InstID, Vals);
2815 
2816     unsigned NumHandlers = CatchSwitch.getNumHandlers();
2817     Vals.push_back(NumHandlers);
2818     for (const BasicBlock *CatchPadBB : CatchSwitch.handlers())
2819       Vals.push_back(VE.getValueID(CatchPadBB));
2820 
2821     if (CatchSwitch.hasUnwindDest())
2822       Vals.push_back(VE.getValueID(CatchSwitch.getUnwindDest()));
2823     break;
2824   }
2825   case Instruction::CallBr: {
2826     const CallBrInst *CBI = cast<CallBrInst>(&I);
2827     const Value *Callee = CBI->getCalledValue();
2828     FunctionType *FTy = CBI->getFunctionType();
2829 
2830     if (CBI->hasOperandBundles())
2831       writeOperandBundles(CBI, InstID);
2832 
2833     Code = bitc::FUNC_CODE_INST_CALLBR;
2834 
2835     Vals.push_back(VE.getAttributeListID(CBI->getAttributes()));
2836 
2837     Vals.push_back(CBI->getCallingConv() << bitc::CALL_CCONV |
2838                    1 << bitc::CALL_EXPLICIT_TYPE);
2839 
2840     Vals.push_back(VE.getValueID(CBI->getDefaultDest()));
2841     Vals.push_back(CBI->getNumIndirectDests());
2842     for (unsigned i = 0, e = CBI->getNumIndirectDests(); i != e; ++i)
2843       Vals.push_back(VE.getValueID(CBI->getIndirectDest(i)));
2844 
2845     Vals.push_back(VE.getTypeID(FTy));
2846     pushValueAndType(Callee, InstID, Vals);
2847 
2848     // Emit value #'s for the fixed parameters.
2849     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
2850       pushValue(I.getOperand(i), InstID, Vals); // fixed param.
2851 
2852     // Emit type/value pairs for varargs params.
2853     if (FTy->isVarArg()) {
2854       for (unsigned i = FTy->getNumParams(), e = CBI->getNumArgOperands();
2855            i != e; ++i)
2856         pushValueAndType(I.getOperand(i), InstID, Vals); // vararg
2857     }
2858     break;
2859   }
2860   case Instruction::Unreachable:
2861     Code = bitc::FUNC_CODE_INST_UNREACHABLE;
2862     AbbrevToUse = FUNCTION_INST_UNREACHABLE_ABBREV;
2863     break;
2864 
2865   case Instruction::PHI: {
2866     const PHINode &PN = cast<PHINode>(I);
2867     Code = bitc::FUNC_CODE_INST_PHI;
2868     // With the newer instruction encoding, forward references could give
2869     // negative valued IDs.  This is most common for PHIs, so we use
2870     // signed VBRs.
2871     SmallVector<uint64_t, 128> Vals64;
2872     Vals64.push_back(VE.getTypeID(PN.getType()));
2873     for (unsigned i = 0, e = PN.getNumIncomingValues(); i != e; ++i) {
2874       pushValueSigned(PN.getIncomingValue(i), InstID, Vals64);
2875       Vals64.push_back(VE.getValueID(PN.getIncomingBlock(i)));
2876     }
2877     // Emit a Vals64 vector and exit.
2878     Stream.EmitRecord(Code, Vals64, AbbrevToUse);
2879     Vals64.clear();
2880     return;
2881   }
2882 
2883   case Instruction::LandingPad: {
2884     const LandingPadInst &LP = cast<LandingPadInst>(I);
2885     Code = bitc::FUNC_CODE_INST_LANDINGPAD;
2886     Vals.push_back(VE.getTypeID(LP.getType()));
2887     Vals.push_back(LP.isCleanup());
2888     Vals.push_back(LP.getNumClauses());
2889     for (unsigned I = 0, E = LP.getNumClauses(); I != E; ++I) {
2890       if (LP.isCatch(I))
2891         Vals.push_back(LandingPadInst::Catch);
2892       else
2893         Vals.push_back(LandingPadInst::Filter);
2894       pushValueAndType(LP.getClause(I), InstID, Vals);
2895     }
2896     break;
2897   }
2898 
2899   case Instruction::Alloca: {
2900     Code = bitc::FUNC_CODE_INST_ALLOCA;
2901     const AllocaInst &AI = cast<AllocaInst>(I);
2902     Vals.push_back(VE.getTypeID(AI.getAllocatedType()));
2903     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
2904     Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
2905     unsigned AlignRecord = Log2_32(AI.getAlignment()) + 1;
2906     assert(Log2_32(Value::MaximumAlignment) + 1 < 1 << 5 &&
2907            "not enough bits for maximum alignment");
2908     assert(AlignRecord < 1 << 5 && "alignment greater than 1 << 64");
2909     AlignRecord |= AI.isUsedWithInAlloca() << 5;
2910     AlignRecord |= 1 << 6;
2911     AlignRecord |= AI.isSwiftError() << 7;
2912     Vals.push_back(AlignRecord);
2913     break;
2914   }
2915 
2916   case Instruction::Load:
2917     if (cast<LoadInst>(I).isAtomic()) {
2918       Code = bitc::FUNC_CODE_INST_LOADATOMIC;
2919       pushValueAndType(I.getOperand(0), InstID, Vals);
2920     } else {
2921       Code = bitc::FUNC_CODE_INST_LOAD;
2922       if (!pushValueAndType(I.getOperand(0), InstID, Vals)) // ptr
2923         AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
2924     }
2925     Vals.push_back(VE.getTypeID(I.getType()));
2926     Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
2927     Vals.push_back(cast<LoadInst>(I).isVolatile());
2928     if (cast<LoadInst>(I).isAtomic()) {
2929       Vals.push_back(getEncodedOrdering(cast<LoadInst>(I).getOrdering()));
2930       Vals.push_back(getEncodedSyncScopeID(cast<LoadInst>(I).getSyncScopeID()));
2931     }
2932     break;
2933   case Instruction::Store:
2934     if (cast<StoreInst>(I).isAtomic())
2935       Code = bitc::FUNC_CODE_INST_STOREATOMIC;
2936     else
2937       Code = bitc::FUNC_CODE_INST_STORE;
2938     pushValueAndType(I.getOperand(1), InstID, Vals); // ptrty + ptr
2939     pushValueAndType(I.getOperand(0), InstID, Vals); // valty + val
2940     Vals.push_back(Log2_32(cast<StoreInst>(I).getAlignment())+1);
2941     Vals.push_back(cast<StoreInst>(I).isVolatile());
2942     if (cast<StoreInst>(I).isAtomic()) {
2943       Vals.push_back(getEncodedOrdering(cast<StoreInst>(I).getOrdering()));
2944       Vals.push_back(
2945           getEncodedSyncScopeID(cast<StoreInst>(I).getSyncScopeID()));
2946     }
2947     break;
2948   case Instruction::AtomicCmpXchg:
2949     Code = bitc::FUNC_CODE_INST_CMPXCHG;
2950     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
2951     pushValueAndType(I.getOperand(1), InstID, Vals); // cmp.
2952     pushValue(I.getOperand(2), InstID, Vals);        // newval.
2953     Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
2954     Vals.push_back(
2955         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getSuccessOrdering()));
2956     Vals.push_back(
2957         getEncodedSyncScopeID(cast<AtomicCmpXchgInst>(I).getSyncScopeID()));
2958     Vals.push_back(
2959         getEncodedOrdering(cast<AtomicCmpXchgInst>(I).getFailureOrdering()));
2960     Vals.push_back(cast<AtomicCmpXchgInst>(I).isWeak());
2961     break;
2962   case Instruction::AtomicRMW:
2963     Code = bitc::FUNC_CODE_INST_ATOMICRMW;
2964     pushValueAndType(I.getOperand(0), InstID, Vals); // ptrty + ptr
2965     pushValue(I.getOperand(1), InstID, Vals);        // val.
2966     Vals.push_back(
2967         getEncodedRMWOperation(cast<AtomicRMWInst>(I).getOperation()));
2968     Vals.push_back(cast<AtomicRMWInst>(I).isVolatile());
2969     Vals.push_back(getEncodedOrdering(cast<AtomicRMWInst>(I).getOrdering()));
2970     Vals.push_back(
2971         getEncodedSyncScopeID(cast<AtomicRMWInst>(I).getSyncScopeID()));
2972     break;
2973   case Instruction::Fence:
2974     Code = bitc::FUNC_CODE_INST_FENCE;
2975     Vals.push_back(getEncodedOrdering(cast<FenceInst>(I).getOrdering()));
2976     Vals.push_back(getEncodedSyncScopeID(cast<FenceInst>(I).getSyncScopeID()));
2977     break;
2978   case Instruction::Call: {
2979     const CallInst &CI = cast<CallInst>(I);
2980     FunctionType *FTy = CI.getFunctionType();
2981 
2982     if (CI.hasOperandBundles())
2983       writeOperandBundles(&CI, InstID);
2984 
2985     Code = bitc::FUNC_CODE_INST_CALL;
2986 
2987     Vals.push_back(VE.getAttributeListID(CI.getAttributes()));
2988 
2989     unsigned Flags = getOptimizationFlags(&I);
2990     Vals.push_back(CI.getCallingConv() << bitc::CALL_CCONV |
2991                    unsigned(CI.isTailCall()) << bitc::CALL_TAIL |
2992                    unsigned(CI.isMustTailCall()) << bitc::CALL_MUSTTAIL |
2993                    1 << bitc::CALL_EXPLICIT_TYPE |
2994                    unsigned(CI.isNoTailCall()) << bitc::CALL_NOTAIL |
2995                    unsigned(Flags != 0) << bitc::CALL_FMF);
2996     if (Flags != 0)
2997       Vals.push_back(Flags);
2998 
2999     Vals.push_back(VE.getTypeID(FTy));
3000     pushValueAndType(CI.getCalledValue(), InstID, Vals); // Callee
3001 
3002     // Emit value #'s for the fixed parameters.
3003     for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i) {
3004       // Check for labels (can happen with asm labels).
3005       if (FTy->getParamType(i)->isLabelTy())
3006         Vals.push_back(VE.getValueID(CI.getArgOperand(i)));
3007       else
3008         pushValue(CI.getArgOperand(i), InstID, Vals); // fixed param.
3009     }
3010 
3011     // Emit type/value pairs for varargs params.
3012     if (FTy->isVarArg()) {
3013       for (unsigned i = FTy->getNumParams(), e = CI.getNumArgOperands();
3014            i != e; ++i)
3015         pushValueAndType(CI.getArgOperand(i), InstID, Vals); // varargs
3016     }
3017     break;
3018   }
3019   case Instruction::VAArg:
3020     Code = bitc::FUNC_CODE_INST_VAARG;
3021     Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));   // valistty
3022     pushValue(I.getOperand(0), InstID, Vals);                   // valist.
3023     Vals.push_back(VE.getTypeID(I.getType())); // restype.
3024     break;
3025   }
3026 
3027   Stream.EmitRecord(Code, Vals, AbbrevToUse);
3028   Vals.clear();
3029 }
3030 
3031 /// Write a GlobalValue VST to the module. The purpose of this data structure is
3032 /// to allow clients to efficiently find the function body.
3033 void ModuleBitcodeWriter::writeGlobalValueSymbolTable(
3034   DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3035   // Get the offset of the VST we are writing, and backpatch it into
3036   // the VST forward declaration record.
3037   uint64_t VSTOffset = Stream.GetCurrentBitNo();
3038   // The BitcodeStartBit was the stream offset of the identification block.
3039   VSTOffset -= bitcodeStartBit();
3040   assert((VSTOffset & 31) == 0 && "VST block not 32-bit aligned");
3041   // Note that we add 1 here because the offset is relative to one word
3042   // before the start of the identification block, which was historically
3043   // always the start of the regular bitcode header.
3044   Stream.BackpatchWord(VSTOffsetPlaceholder, VSTOffset / 32 + 1);
3045 
3046   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3047 
3048   auto Abbv = std::make_shared<BitCodeAbbrev>();
3049   Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_FNENTRY));
3050   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // value id
3051   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // funcoffset
3052   unsigned FnEntryAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3053 
3054   for (const Function &F : M) {
3055     uint64_t Record[2];
3056 
3057     if (F.isDeclaration())
3058       continue;
3059 
3060     Record[0] = VE.getValueID(&F);
3061 
3062     // Save the word offset of the function (from the start of the
3063     // actual bitcode written to the stream).
3064     uint64_t BitcodeIndex = FunctionToBitcodeIndex[&F] - bitcodeStartBit();
3065     assert((BitcodeIndex & 31) == 0 && "function block not 32-bit aligned");
3066     // Note that we add 1 here because the offset is relative to one word
3067     // before the start of the identification block, which was historically
3068     // always the start of the regular bitcode header.
3069     Record[1] = BitcodeIndex / 32 + 1;
3070 
3071     Stream.EmitRecord(bitc::VST_CODE_FNENTRY, Record, FnEntryAbbrev);
3072   }
3073 
3074   Stream.ExitBlock();
3075 }
3076 
3077 /// Emit names for arguments, instructions and basic blocks in a function.
3078 void ModuleBitcodeWriter::writeFunctionLevelValueSymbolTable(
3079     const ValueSymbolTable &VST) {
3080   if (VST.empty())
3081     return;
3082 
3083   Stream.EnterSubblock(bitc::VALUE_SYMTAB_BLOCK_ID, 4);
3084 
3085   // FIXME: Set up the abbrev, we know how many values there are!
3086   // FIXME: We know if the type names can use 7-bit ascii.
3087   SmallVector<uint64_t, 64> NameVals;
3088 
3089   for (const ValueName &Name : VST) {
3090     // Figure out the encoding to use for the name.
3091     StringEncoding Bits = getStringEncoding(Name.getKey());
3092 
3093     unsigned AbbrevToUse = VST_ENTRY_8_ABBREV;
3094     NameVals.push_back(VE.getValueID(Name.getValue()));
3095 
3096     // VST_CODE_ENTRY:   [valueid, namechar x N]
3097     // VST_CODE_BBENTRY: [bbid, namechar x N]
3098     unsigned Code;
3099     if (isa<BasicBlock>(Name.getValue())) {
3100       Code = bitc::VST_CODE_BBENTRY;
3101       if (Bits == SE_Char6)
3102         AbbrevToUse = VST_BBENTRY_6_ABBREV;
3103     } else {
3104       Code = bitc::VST_CODE_ENTRY;
3105       if (Bits == SE_Char6)
3106         AbbrevToUse = VST_ENTRY_6_ABBREV;
3107       else if (Bits == SE_Fixed7)
3108         AbbrevToUse = VST_ENTRY_7_ABBREV;
3109     }
3110 
3111     for (const auto P : Name.getKey())
3112       NameVals.push_back((unsigned char)P);
3113 
3114     // Emit the finished record.
3115     Stream.EmitRecord(Code, NameVals, AbbrevToUse);
3116     NameVals.clear();
3117   }
3118 
3119   Stream.ExitBlock();
3120 }
3121 
3122 void ModuleBitcodeWriter::writeUseList(UseListOrder &&Order) {
3123   assert(Order.Shuffle.size() >= 2 && "Shuffle too small");
3124   unsigned Code;
3125   if (isa<BasicBlock>(Order.V))
3126     Code = bitc::USELIST_CODE_BB;
3127   else
3128     Code = bitc::USELIST_CODE_DEFAULT;
3129 
3130   SmallVector<uint64_t, 64> Record(Order.Shuffle.begin(), Order.Shuffle.end());
3131   Record.push_back(VE.getValueID(Order.V));
3132   Stream.EmitRecord(Code, Record);
3133 }
3134 
3135 void ModuleBitcodeWriter::writeUseListBlock(const Function *F) {
3136   assert(VE.shouldPreserveUseListOrder() &&
3137          "Expected to be preserving use-list order");
3138 
3139   auto hasMore = [&]() {
3140     return !VE.UseListOrders.empty() && VE.UseListOrders.back().F == F;
3141   };
3142   if (!hasMore())
3143     // Nothing to do.
3144     return;
3145 
3146   Stream.EnterSubblock(bitc::USELIST_BLOCK_ID, 3);
3147   while (hasMore()) {
3148     writeUseList(std::move(VE.UseListOrders.back()));
3149     VE.UseListOrders.pop_back();
3150   }
3151   Stream.ExitBlock();
3152 }
3153 
3154 /// Emit a function body to the module stream.
3155 void ModuleBitcodeWriter::writeFunction(
3156     const Function &F,
3157     DenseMap<const Function *, uint64_t> &FunctionToBitcodeIndex) {
3158   // Save the bitcode index of the start of this function block for recording
3159   // in the VST.
3160   FunctionToBitcodeIndex[&F] = Stream.GetCurrentBitNo();
3161 
3162   Stream.EnterSubblock(bitc::FUNCTION_BLOCK_ID, 4);
3163   VE.incorporateFunction(F);
3164 
3165   SmallVector<unsigned, 64> Vals;
3166 
3167   // Emit the number of basic blocks, so the reader can create them ahead of
3168   // time.
3169   Vals.push_back(VE.getBasicBlocks().size());
3170   Stream.EmitRecord(bitc::FUNC_CODE_DECLAREBLOCKS, Vals);
3171   Vals.clear();
3172 
3173   // If there are function-local constants, emit them now.
3174   unsigned CstStart, CstEnd;
3175   VE.getFunctionConstantRange(CstStart, CstEnd);
3176   writeConstants(CstStart, CstEnd, false);
3177 
3178   // If there is function-local metadata, emit it now.
3179   writeFunctionMetadata(F);
3180 
3181   // Keep a running idea of what the instruction ID is.
3182   unsigned InstID = CstEnd;
3183 
3184   bool NeedsMetadataAttachment = F.hasMetadata();
3185 
3186   DILocation *LastDL = nullptr;
3187   // Finally, emit all the instructions, in order.
3188   for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
3189     for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
3190          I != E; ++I) {
3191       writeInstruction(*I, InstID, Vals);
3192 
3193       if (!I->getType()->isVoidTy())
3194         ++InstID;
3195 
3196       // If the instruction has metadata, write a metadata attachment later.
3197       NeedsMetadataAttachment |= I->hasMetadataOtherThanDebugLoc();
3198 
3199       // If the instruction has a debug location, emit it.
3200       DILocation *DL = I->getDebugLoc();
3201       if (!DL)
3202         continue;
3203 
3204       if (DL == LastDL) {
3205         // Just repeat the same debug loc as last time.
3206         Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC_AGAIN, Vals);
3207         continue;
3208       }
3209 
3210       Vals.push_back(DL->getLine());
3211       Vals.push_back(DL->getColumn());
3212       Vals.push_back(VE.getMetadataOrNullID(DL->getScope()));
3213       Vals.push_back(VE.getMetadataOrNullID(DL->getInlinedAt()));
3214       Vals.push_back(DL->isImplicitCode());
3215       Stream.EmitRecord(bitc::FUNC_CODE_DEBUG_LOC, Vals);
3216       Vals.clear();
3217 
3218       LastDL = DL;
3219     }
3220 
3221   // Emit names for all the instructions etc.
3222   if (auto *Symtab = F.getValueSymbolTable())
3223     writeFunctionLevelValueSymbolTable(*Symtab);
3224 
3225   if (NeedsMetadataAttachment)
3226     writeFunctionMetadataAttachment(F);
3227   if (VE.shouldPreserveUseListOrder())
3228     writeUseListBlock(&F);
3229   VE.purgeFunction();
3230   Stream.ExitBlock();
3231 }
3232 
3233 // Emit blockinfo, which defines the standard abbreviations etc.
3234 void ModuleBitcodeWriter::writeBlockInfo() {
3235   // We only want to emit block info records for blocks that have multiple
3236   // instances: CONSTANTS_BLOCK, FUNCTION_BLOCK and VALUE_SYMTAB_BLOCK.
3237   // Other blocks can define their abbrevs inline.
3238   Stream.EnterBlockInfoBlock();
3239 
3240   { // 8-bit fixed-width VST_CODE_ENTRY/VST_CODE_BBENTRY strings.
3241     auto Abbv = std::make_shared<BitCodeAbbrev>();
3242     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 3));
3243     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3244     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3245     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3246     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3247         VST_ENTRY_8_ABBREV)
3248       llvm_unreachable("Unexpected abbrev ordering!");
3249   }
3250 
3251   { // 7-bit fixed width VST_CODE_ENTRY strings.
3252     auto Abbv = std::make_shared<BitCodeAbbrev>();
3253     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3254     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3255     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3256     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3257     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3258         VST_ENTRY_7_ABBREV)
3259       llvm_unreachable("Unexpected abbrev ordering!");
3260   }
3261   { // 6-bit char6 VST_CODE_ENTRY strings.
3262     auto Abbv = std::make_shared<BitCodeAbbrev>();
3263     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_ENTRY));
3264     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3265     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3266     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3267     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3268         VST_ENTRY_6_ABBREV)
3269       llvm_unreachable("Unexpected abbrev ordering!");
3270   }
3271   { // 6-bit char6 VST_CODE_BBENTRY strings.
3272     auto Abbv = std::make_shared<BitCodeAbbrev>();
3273     Abbv->Add(BitCodeAbbrevOp(bitc::VST_CODE_BBENTRY));
3274     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3275     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3276     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3277     if (Stream.EmitBlockInfoAbbrev(bitc::VALUE_SYMTAB_BLOCK_ID, Abbv) !=
3278         VST_BBENTRY_6_ABBREV)
3279       llvm_unreachable("Unexpected abbrev ordering!");
3280   }
3281 
3282   { // SETTYPE abbrev for CONSTANTS_BLOCK.
3283     auto Abbv = std::make_shared<BitCodeAbbrev>();
3284     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_SETTYPE));
3285     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,
3286                               VE.computeBitsRequiredForTypeIndicies()));
3287     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3288         CONSTANTS_SETTYPE_ABBREV)
3289       llvm_unreachable("Unexpected abbrev ordering!");
3290   }
3291 
3292   { // INTEGER abbrev for CONSTANTS_BLOCK.
3293     auto Abbv = std::make_shared<BitCodeAbbrev>();
3294     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_INTEGER));
3295     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3296     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3297         CONSTANTS_INTEGER_ABBREV)
3298       llvm_unreachable("Unexpected abbrev ordering!");
3299   }
3300 
3301   { // CE_CAST abbrev for CONSTANTS_BLOCK.
3302     auto Abbv = std::make_shared<BitCodeAbbrev>();
3303     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CE_CAST));
3304     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // cast opc
3305     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // typeid
3306                               VE.computeBitsRequiredForTypeIndicies()));
3307     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));    // value id
3308 
3309     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3310         CONSTANTS_CE_CAST_Abbrev)
3311       llvm_unreachable("Unexpected abbrev ordering!");
3312   }
3313   { // NULL abbrev for CONSTANTS_BLOCK.
3314     auto Abbv = std::make_shared<BitCodeAbbrev>();
3315     Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_NULL));
3316     if (Stream.EmitBlockInfoAbbrev(bitc::CONSTANTS_BLOCK_ID, Abbv) !=
3317         CONSTANTS_NULL_Abbrev)
3318       llvm_unreachable("Unexpected abbrev ordering!");
3319   }
3320 
3321   // FIXME: This should only use space for first class types!
3322 
3323   { // INST_LOAD abbrev for FUNCTION_BLOCK.
3324     auto Abbv = std::make_shared<BitCodeAbbrev>();
3325     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
3326     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
3327     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,    // dest ty
3328                               VE.computeBitsRequiredForTypeIndicies()));
3329     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
3330     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
3331     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3332         FUNCTION_INST_LOAD_ABBREV)
3333       llvm_unreachable("Unexpected abbrev ordering!");
3334   }
3335   { // INST_UNOP abbrev for FUNCTION_BLOCK.
3336     auto Abbv = std::make_shared<BitCodeAbbrev>();
3337     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3338     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3339     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3340     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3341         FUNCTION_INST_UNOP_ABBREV)
3342       llvm_unreachable("Unexpected abbrev ordering!");
3343   }
3344   { // INST_UNOP_FLAGS abbrev for FUNCTION_BLOCK.
3345     auto Abbv = std::make_shared<BitCodeAbbrev>();
3346     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNOP));
3347     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3348     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3349     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3350     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3351         FUNCTION_INST_UNOP_FLAGS_ABBREV)
3352       llvm_unreachable("Unexpected abbrev ordering!");
3353   }
3354   { // INST_BINOP abbrev for FUNCTION_BLOCK.
3355     auto Abbv = std::make_shared<BitCodeAbbrev>();
3356     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3357     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3358     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3359     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3360     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3361         FUNCTION_INST_BINOP_ABBREV)
3362       llvm_unreachable("Unexpected abbrev ordering!");
3363   }
3364   { // INST_BINOP_FLAGS abbrev for FUNCTION_BLOCK.
3365     auto Abbv = std::make_shared<BitCodeAbbrev>();
3366     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_BINOP));
3367     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // LHS
3368     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // RHS
3369     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4)); // opc
3370     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8)); // flags
3371     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3372         FUNCTION_INST_BINOP_FLAGS_ABBREV)
3373       llvm_unreachable("Unexpected abbrev ordering!");
3374   }
3375   { // INST_CAST abbrev for FUNCTION_BLOCK.
3376     auto Abbv = std::make_shared<BitCodeAbbrev>();
3377     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_CAST));
3378     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));    // OpVal
3379     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed,       // dest ty
3380                               VE.computeBitsRequiredForTypeIndicies()));
3381     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 4));  // opc
3382     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3383         FUNCTION_INST_CAST_ABBREV)
3384       llvm_unreachable("Unexpected abbrev ordering!");
3385   }
3386 
3387   { // INST_RET abbrev for FUNCTION_BLOCK.
3388     auto Abbv = std::make_shared<BitCodeAbbrev>();
3389     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3390     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3391         FUNCTION_INST_RET_VOID_ABBREV)
3392       llvm_unreachable("Unexpected abbrev ordering!");
3393   }
3394   { // INST_RET abbrev for FUNCTION_BLOCK.
3395     auto Abbv = std::make_shared<BitCodeAbbrev>();
3396     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_RET));
3397     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // ValID
3398     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3399         FUNCTION_INST_RET_VAL_ABBREV)
3400       llvm_unreachable("Unexpected abbrev ordering!");
3401   }
3402   { // INST_UNREACHABLE abbrev for FUNCTION_BLOCK.
3403     auto Abbv = std::make_shared<BitCodeAbbrev>();
3404     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_UNREACHABLE));
3405     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3406         FUNCTION_INST_UNREACHABLE_ABBREV)
3407       llvm_unreachable("Unexpected abbrev ordering!");
3408   }
3409   {
3410     auto Abbv = std::make_shared<BitCodeAbbrev>();
3411     Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_GEP));
3412     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1));
3413     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, // dest ty
3414                               Log2_32_Ceil(VE.getTypes().size() + 1)));
3415     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3416     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
3417     if (Stream.EmitBlockInfoAbbrev(bitc::FUNCTION_BLOCK_ID, Abbv) !=
3418         FUNCTION_INST_GEP_ABBREV)
3419       llvm_unreachable("Unexpected abbrev ordering!");
3420   }
3421 
3422   Stream.ExitBlock();
3423 }
3424 
3425 /// Write the module path strings, currently only used when generating
3426 /// a combined index file.
3427 void IndexBitcodeWriter::writeModStrings() {
3428   Stream.EnterSubblock(bitc::MODULE_STRTAB_BLOCK_ID, 3);
3429 
3430   // TODO: See which abbrev sizes we actually need to emit
3431 
3432   // 8-bit fixed-width MST_ENTRY strings.
3433   auto Abbv = std::make_shared<BitCodeAbbrev>();
3434   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3435   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3436   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3437   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
3438   unsigned Abbrev8Bit = Stream.EmitAbbrev(std::move(Abbv));
3439 
3440   // 7-bit fixed width MST_ENTRY strings.
3441   Abbv = std::make_shared<BitCodeAbbrev>();
3442   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3443   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3444   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3445   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
3446   unsigned Abbrev7Bit = Stream.EmitAbbrev(std::move(Abbv));
3447 
3448   // 6-bit char6 MST_ENTRY strings.
3449   Abbv = std::make_shared<BitCodeAbbrev>();
3450   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_ENTRY));
3451   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3452   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3453   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
3454   unsigned Abbrev6Bit = Stream.EmitAbbrev(std::move(Abbv));
3455 
3456   // Module Hash, 160 bits SHA1. Optionally, emitted after each MST_CODE_ENTRY.
3457   Abbv = std::make_shared<BitCodeAbbrev>();
3458   Abbv->Add(BitCodeAbbrevOp(bitc::MST_CODE_HASH));
3459   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3460   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3461   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3462   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3463   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 32));
3464   unsigned AbbrevHash = Stream.EmitAbbrev(std::move(Abbv));
3465 
3466   SmallVector<unsigned, 64> Vals;
3467   forEachModule(
3468       [&](const StringMapEntry<std::pair<uint64_t, ModuleHash>> &MPSE) {
3469         StringRef Key = MPSE.getKey();
3470         const auto &Value = MPSE.getValue();
3471         StringEncoding Bits = getStringEncoding(Key);
3472         unsigned AbbrevToUse = Abbrev8Bit;
3473         if (Bits == SE_Char6)
3474           AbbrevToUse = Abbrev6Bit;
3475         else if (Bits == SE_Fixed7)
3476           AbbrevToUse = Abbrev7Bit;
3477 
3478         Vals.push_back(Value.first);
3479         Vals.append(Key.begin(), Key.end());
3480 
3481         // Emit the finished record.
3482         Stream.EmitRecord(bitc::MST_CODE_ENTRY, Vals, AbbrevToUse);
3483 
3484         // Emit an optional hash for the module now
3485         const auto &Hash = Value.second;
3486         if (llvm::any_of(Hash, [](uint32_t H) { return H; })) {
3487           Vals.assign(Hash.begin(), Hash.end());
3488           // Emit the hash record.
3489           Stream.EmitRecord(bitc::MST_CODE_HASH, Vals, AbbrevHash);
3490         }
3491 
3492         Vals.clear();
3493       });
3494   Stream.ExitBlock();
3495 }
3496 
3497 /// Write the function type metadata related records that need to appear before
3498 /// a function summary entry (whether per-module or combined).
3499 static void writeFunctionTypeMetadataRecords(BitstreamWriter &Stream,
3500                                              FunctionSummary *FS) {
3501   if (!FS->type_tests().empty())
3502     Stream.EmitRecord(bitc::FS_TYPE_TESTS, FS->type_tests());
3503 
3504   SmallVector<uint64_t, 64> Record;
3505 
3506   auto WriteVFuncIdVec = [&](uint64_t Ty,
3507                              ArrayRef<FunctionSummary::VFuncId> VFs) {
3508     if (VFs.empty())
3509       return;
3510     Record.clear();
3511     for (auto &VF : VFs) {
3512       Record.push_back(VF.GUID);
3513       Record.push_back(VF.Offset);
3514     }
3515     Stream.EmitRecord(Ty, Record);
3516   };
3517 
3518   WriteVFuncIdVec(bitc::FS_TYPE_TEST_ASSUME_VCALLS,
3519                   FS->type_test_assume_vcalls());
3520   WriteVFuncIdVec(bitc::FS_TYPE_CHECKED_LOAD_VCALLS,
3521                   FS->type_checked_load_vcalls());
3522 
3523   auto WriteConstVCallVec = [&](uint64_t Ty,
3524                                 ArrayRef<FunctionSummary::ConstVCall> VCs) {
3525     for (auto &VC : VCs) {
3526       Record.clear();
3527       Record.push_back(VC.VFunc.GUID);
3528       Record.push_back(VC.VFunc.Offset);
3529       Record.insert(Record.end(), VC.Args.begin(), VC.Args.end());
3530       Stream.EmitRecord(Ty, Record);
3531     }
3532   };
3533 
3534   WriteConstVCallVec(bitc::FS_TYPE_TEST_ASSUME_CONST_VCALL,
3535                      FS->type_test_assume_const_vcalls());
3536   WriteConstVCallVec(bitc::FS_TYPE_CHECKED_LOAD_CONST_VCALL,
3537                      FS->type_checked_load_const_vcalls());
3538 }
3539 
3540 /// Collect type IDs from type tests used by function.
3541 static void
3542 getReferencedTypeIds(FunctionSummary *FS,
3543                      std::set<GlobalValue::GUID> &ReferencedTypeIds) {
3544   if (!FS->type_tests().empty())
3545     for (auto &TT : FS->type_tests())
3546       ReferencedTypeIds.insert(TT);
3547 
3548   auto GetReferencedTypesFromVFuncIdVec =
3549       [&](ArrayRef<FunctionSummary::VFuncId> VFs) {
3550         for (auto &VF : VFs)
3551           ReferencedTypeIds.insert(VF.GUID);
3552       };
3553 
3554   GetReferencedTypesFromVFuncIdVec(FS->type_test_assume_vcalls());
3555   GetReferencedTypesFromVFuncIdVec(FS->type_checked_load_vcalls());
3556 
3557   auto GetReferencedTypesFromConstVCallVec =
3558       [&](ArrayRef<FunctionSummary::ConstVCall> VCs) {
3559         for (auto &VC : VCs)
3560           ReferencedTypeIds.insert(VC.VFunc.GUID);
3561       };
3562 
3563   GetReferencedTypesFromConstVCallVec(FS->type_test_assume_const_vcalls());
3564   GetReferencedTypesFromConstVCallVec(FS->type_checked_load_const_vcalls());
3565 }
3566 
3567 static void writeWholeProgramDevirtResolutionByArg(
3568     SmallVector<uint64_t, 64> &NameVals, const std::vector<uint64_t> &args,
3569     const WholeProgramDevirtResolution::ByArg &ByArg) {
3570   NameVals.push_back(args.size());
3571   NameVals.insert(NameVals.end(), args.begin(), args.end());
3572 
3573   NameVals.push_back(ByArg.TheKind);
3574   NameVals.push_back(ByArg.Info);
3575   NameVals.push_back(ByArg.Byte);
3576   NameVals.push_back(ByArg.Bit);
3577 }
3578 
3579 static void writeWholeProgramDevirtResolution(
3580     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3581     uint64_t Id, const WholeProgramDevirtResolution &Wpd) {
3582   NameVals.push_back(Id);
3583 
3584   NameVals.push_back(Wpd.TheKind);
3585   NameVals.push_back(StrtabBuilder.add(Wpd.SingleImplName));
3586   NameVals.push_back(Wpd.SingleImplName.size());
3587 
3588   NameVals.push_back(Wpd.ResByArg.size());
3589   for (auto &A : Wpd.ResByArg)
3590     writeWholeProgramDevirtResolutionByArg(NameVals, A.first, A.second);
3591 }
3592 
3593 static void writeTypeIdSummaryRecord(SmallVector<uint64_t, 64> &NameVals,
3594                                      StringTableBuilder &StrtabBuilder,
3595                                      const std::string &Id,
3596                                      const TypeIdSummary &Summary) {
3597   NameVals.push_back(StrtabBuilder.add(Id));
3598   NameVals.push_back(Id.size());
3599 
3600   NameVals.push_back(Summary.TTRes.TheKind);
3601   NameVals.push_back(Summary.TTRes.SizeM1BitWidth);
3602   NameVals.push_back(Summary.TTRes.AlignLog2);
3603   NameVals.push_back(Summary.TTRes.SizeM1);
3604   NameVals.push_back(Summary.TTRes.BitMask);
3605   NameVals.push_back(Summary.TTRes.InlineBits);
3606 
3607   for (auto &W : Summary.WPDRes)
3608     writeWholeProgramDevirtResolution(NameVals, StrtabBuilder, W.first,
3609                                       W.second);
3610 }
3611 
3612 static void writeTypeIdCompatibleVtableSummaryRecord(
3613     SmallVector<uint64_t, 64> &NameVals, StringTableBuilder &StrtabBuilder,
3614     const std::string &Id, const TypeIdCompatibleVtableInfo &Summary,
3615     ValueEnumerator &VE) {
3616   NameVals.push_back(StrtabBuilder.add(Id));
3617   NameVals.push_back(Id.size());
3618 
3619   for (auto &P : Summary) {
3620     NameVals.push_back(P.AddressPointOffset);
3621     NameVals.push_back(VE.getValueID(P.VTableVI.getValue()));
3622   }
3623 }
3624 
3625 // Helper to emit a single function summary record.
3626 void ModuleBitcodeWriterBase::writePerModuleFunctionSummaryRecord(
3627     SmallVector<uint64_t, 64> &NameVals, GlobalValueSummary *Summary,
3628     unsigned ValueID, unsigned FSCallsAbbrev, unsigned FSCallsProfileAbbrev,
3629     const Function &F) {
3630   NameVals.push_back(ValueID);
3631 
3632   FunctionSummary *FS = cast<FunctionSummary>(Summary);
3633   writeFunctionTypeMetadataRecords(Stream, FS);
3634 
3635   auto SpecialRefCnts = FS->specialRefCounts();
3636   NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
3637   NameVals.push_back(FS->instCount());
3638   NameVals.push_back(getEncodedFFlags(FS->fflags()));
3639   NameVals.push_back(FS->refs().size());
3640   NameVals.push_back(SpecialRefCnts.first);  // rorefcnt
3641   NameVals.push_back(SpecialRefCnts.second); // worefcnt
3642 
3643   for (auto &RI : FS->refs())
3644     NameVals.push_back(VE.getValueID(RI.getValue()));
3645 
3646   bool HasProfileData =
3647       F.hasProfileData() || ForceSummaryEdgesCold != FunctionSummary::FSHT_None;
3648   for (auto &ECI : FS->calls()) {
3649     NameVals.push_back(getValueId(ECI.first));
3650     if (HasProfileData)
3651       NameVals.push_back(static_cast<uint8_t>(ECI.second.Hotness));
3652     else if (WriteRelBFToSummary)
3653       NameVals.push_back(ECI.second.RelBlockFreq);
3654   }
3655 
3656   unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
3657   unsigned Code =
3658       (HasProfileData ? bitc::FS_PERMODULE_PROFILE
3659                       : (WriteRelBFToSummary ? bitc::FS_PERMODULE_RELBF
3660                                              : bitc::FS_PERMODULE));
3661 
3662   // Emit the finished record.
3663   Stream.EmitRecord(Code, NameVals, FSAbbrev);
3664   NameVals.clear();
3665 }
3666 
3667 // Collect the global value references in the given variable's initializer,
3668 // and emit them in a summary record.
3669 void ModuleBitcodeWriterBase::writeModuleLevelReferences(
3670     const GlobalVariable &V, SmallVector<uint64_t, 64> &NameVals,
3671     unsigned FSModRefsAbbrev, unsigned FSModVTableRefsAbbrev) {
3672   auto VI = Index->getValueInfo(V.getGUID());
3673   if (!VI || VI.getSummaryList().empty()) {
3674     // Only declarations should not have a summary (a declaration might however
3675     // have a summary if the def was in module level asm).
3676     assert(V.isDeclaration());
3677     return;
3678   }
3679   auto *Summary = VI.getSummaryList()[0].get();
3680   NameVals.push_back(VE.getValueID(&V));
3681   GlobalVarSummary *VS = cast<GlobalVarSummary>(Summary);
3682   NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
3683   NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
3684 
3685   auto VTableFuncs = VS->vTableFuncs();
3686   if (!VTableFuncs.empty())
3687     NameVals.push_back(VS->refs().size());
3688 
3689   unsigned SizeBeforeRefs = NameVals.size();
3690   for (auto &RI : VS->refs())
3691     NameVals.push_back(VE.getValueID(RI.getValue()));
3692   // Sort the refs for determinism output, the vector returned by FS->refs() has
3693   // been initialized from a DenseSet.
3694   llvm::sort(NameVals.begin() + SizeBeforeRefs, NameVals.end());
3695 
3696   if (VTableFuncs.empty())
3697     Stream.EmitRecord(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS, NameVals,
3698                       FSModRefsAbbrev);
3699   else {
3700     // VTableFuncs pairs should already be sorted by offset.
3701     for (auto &P : VTableFuncs) {
3702       NameVals.push_back(VE.getValueID(P.FuncVI.getValue()));
3703       NameVals.push_back(P.VTableOffset);
3704     }
3705 
3706     Stream.EmitRecord(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS, NameVals,
3707                       FSModVTableRefsAbbrev);
3708   }
3709   NameVals.clear();
3710 }
3711 
3712 // Current version for the summary.
3713 // This is bumped whenever we introduce changes in the way some record are
3714 // interpreted, like flags for instance.
3715 static const uint64_t INDEX_VERSION = 7;
3716 
3717 /// Emit the per-module summary section alongside the rest of
3718 /// the module's bitcode.
3719 void ModuleBitcodeWriterBase::writePerModuleGlobalValueSummary() {
3720   // By default we compile with ThinLTO if the module has a summary, but the
3721   // client can request full LTO with a module flag.
3722   bool IsThinLTO = true;
3723   if (auto *MD =
3724           mdconst::extract_or_null<ConstantInt>(M.getModuleFlag("ThinLTO")))
3725     IsThinLTO = MD->getZExtValue();
3726   Stream.EnterSubblock(IsThinLTO ? bitc::GLOBALVAL_SUMMARY_BLOCK_ID
3727                                  : bitc::FULL_LTO_GLOBALVAL_SUMMARY_BLOCK_ID,
3728                        4);
3729 
3730   Stream.EmitRecord(bitc::FS_VERSION, ArrayRef<uint64_t>{INDEX_VERSION});
3731 
3732   // Write the index flags.
3733   uint64_t Flags = 0;
3734   // Bits 1-3 are set only in the combined index, skip them.
3735   if (Index->enableSplitLTOUnit())
3736     Flags |= 0x8;
3737   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Flags});
3738 
3739   if (Index->begin() == Index->end()) {
3740     Stream.ExitBlock();
3741     return;
3742   }
3743 
3744   for (const auto &GVI : valueIds()) {
3745     Stream.EmitRecord(bitc::FS_VALUE_GUID,
3746                       ArrayRef<uint64_t>{GVI.second, GVI.first});
3747   }
3748 
3749   // Abbrev for FS_PERMODULE_PROFILE.
3750   auto Abbv = std::make_shared<BitCodeAbbrev>();
3751   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_PROFILE));
3752   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3753   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3754   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3755   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3756   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3757   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
3758   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
3759   // numrefs x valueid, n x (valueid, hotness)
3760   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3761   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3762   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3763 
3764   // Abbrev for FS_PERMODULE or FS_PERMODULE_RELBF.
3765   Abbv = std::make_shared<BitCodeAbbrev>();
3766   if (WriteRelBFToSummary)
3767     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_RELBF));
3768   else
3769     Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE));
3770   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3771   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3772   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3773   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3774   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3775   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
3776   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
3777   // numrefs x valueid, n x (valueid [, rel_block_freq])
3778   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3779   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3780   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3781 
3782   // Abbrev for FS_PERMODULE_GLOBALVAR_INIT_REFS.
3783   Abbv = std::make_shared<BitCodeAbbrev>();
3784   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_GLOBALVAR_INIT_REFS));
3785   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
3786   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
3787   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));  // valueids
3788   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3789   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3790 
3791   // Abbrev for FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS.
3792   Abbv = std::make_shared<BitCodeAbbrev>();
3793   Abbv->Add(BitCodeAbbrevOp(bitc::FS_PERMODULE_VTABLE_GLOBALVAR_INIT_REFS));
3794   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // valueid
3795   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // flags
3796   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numrefs
3797   // numrefs x valueid, n x (valueid , offset)
3798   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3799   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3800   unsigned FSModVTableRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3801 
3802   // Abbrev for FS_ALIAS.
3803   Abbv = std::make_shared<BitCodeAbbrev>();
3804   Abbv->Add(BitCodeAbbrevOp(bitc::FS_ALIAS));
3805   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3806   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3807   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3808   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3809 
3810   // Abbrev for FS_TYPE_ID_METADATA
3811   Abbv = std::make_shared<BitCodeAbbrev>();
3812   Abbv->Add(BitCodeAbbrevOp(bitc::FS_TYPE_ID_METADATA));
3813   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid strtab index
3814   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8)); // typeid length
3815   // n x (valueid , offset)
3816   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3817   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3818   unsigned TypeIdCompatibleVtableAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3819 
3820   SmallVector<uint64_t, 64> NameVals;
3821   // Iterate over the list of functions instead of the Index to
3822   // ensure the ordering is stable.
3823   for (const Function &F : M) {
3824     // Summary emission does not support anonymous functions, they have to
3825     // renamed using the anonymous function renaming pass.
3826     if (!F.hasName())
3827       report_fatal_error("Unexpected anonymous function when writing summary");
3828 
3829     ValueInfo VI = Index->getValueInfo(F.getGUID());
3830     if (!VI || VI.getSummaryList().empty()) {
3831       // Only declarations should not have a summary (a declaration might
3832       // however have a summary if the def was in module level asm).
3833       assert(F.isDeclaration());
3834       continue;
3835     }
3836     auto *Summary = VI.getSummaryList()[0].get();
3837     writePerModuleFunctionSummaryRecord(NameVals, Summary, VE.getValueID(&F),
3838                                         FSCallsAbbrev, FSCallsProfileAbbrev, F);
3839   }
3840 
3841   // Capture references from GlobalVariable initializers, which are outside
3842   // of a function scope.
3843   for (const GlobalVariable &G : M.globals())
3844     writeModuleLevelReferences(G, NameVals, FSModRefsAbbrev,
3845                                FSModVTableRefsAbbrev);
3846 
3847   for (const GlobalAlias &A : M.aliases()) {
3848     auto *Aliasee = A.getBaseObject();
3849     if (!Aliasee->hasName())
3850       // Nameless function don't have an entry in the summary, skip it.
3851       continue;
3852     auto AliasId = VE.getValueID(&A);
3853     auto AliaseeId = VE.getValueID(Aliasee);
3854     NameVals.push_back(AliasId);
3855     auto *Summary = Index->getGlobalValueSummary(A);
3856     AliasSummary *AS = cast<AliasSummary>(Summary);
3857     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
3858     NameVals.push_back(AliaseeId);
3859     Stream.EmitRecord(bitc::FS_ALIAS, NameVals, FSAliasAbbrev);
3860     NameVals.clear();
3861   }
3862 
3863   for (auto &S : Index->typeIdCompatibleVtableMap()) {
3864     writeTypeIdCompatibleVtableSummaryRecord(NameVals, StrtabBuilder, S.first,
3865                                              S.second, VE);
3866     Stream.EmitRecord(bitc::FS_TYPE_ID_METADATA, NameVals,
3867                       TypeIdCompatibleVtableAbbrev);
3868     NameVals.clear();
3869   }
3870 
3871   Stream.ExitBlock();
3872 }
3873 
3874 /// Emit the combined summary section into the combined index file.
3875 void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
3876   Stream.EnterSubblock(bitc::GLOBALVAL_SUMMARY_BLOCK_ID, 3);
3877   Stream.EmitRecord(bitc::FS_VERSION, ArrayRef<uint64_t>{INDEX_VERSION});
3878 
3879   // Write the index flags.
3880   uint64_t Flags = 0;
3881   if (Index.withGlobalValueDeadStripping())
3882     Flags |= 0x1;
3883   if (Index.skipModuleByDistributedBackend())
3884     Flags |= 0x2;
3885   if (Index.hasSyntheticEntryCounts())
3886     Flags |= 0x4;
3887   if (Index.enableSplitLTOUnit())
3888     Flags |= 0x8;
3889   if (Index.partiallySplitLTOUnits())
3890     Flags |= 0x10;
3891   Stream.EmitRecord(bitc::FS_FLAGS, ArrayRef<uint64_t>{Flags});
3892 
3893   for (const auto &GVI : valueIds()) {
3894     Stream.EmitRecord(bitc::FS_VALUE_GUID,
3895                       ArrayRef<uint64_t>{GVI.second, GVI.first});
3896   }
3897 
3898   // Abbrev for FS_COMBINED.
3899   auto Abbv = std::make_shared<BitCodeAbbrev>();
3900   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED));
3901   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3902   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3903   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3904   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3905   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3906   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
3907   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3908   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
3909   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
3910   // numrefs x valueid, n x (valueid)
3911   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3912   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3913   unsigned FSCallsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3914 
3915   // Abbrev for FS_COMBINED_PROFILE.
3916   Abbv = std::make_shared<BitCodeAbbrev>();
3917   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_PROFILE));
3918   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3919   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3920   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3921   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // instcount
3922   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // fflags
3923   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // entrycount
3924   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // numrefs
3925   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // rorefcnt
3926   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4));   // worefcnt
3927   // numrefs x valueid, n x (valueid, hotness)
3928   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
3929   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3930   unsigned FSCallsProfileAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3931 
3932   // Abbrev for FS_COMBINED_GLOBALVAR_INIT_REFS.
3933   Abbv = std::make_shared<BitCodeAbbrev>();
3934   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS));
3935   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3936   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3937   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3938   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));    // valueids
3939   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
3940   unsigned FSModRefsAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3941 
3942   // Abbrev for FS_COMBINED_ALIAS.
3943   Abbv = std::make_shared<BitCodeAbbrev>();
3944   Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_ALIAS));
3945   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3946   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // modid
3947   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));   // flags
3948   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));   // valueid
3949   unsigned FSAliasAbbrev = Stream.EmitAbbrev(std::move(Abbv));
3950 
3951   // The aliases are emitted as a post-pass, and will point to the value
3952   // id of the aliasee. Save them in a vector for post-processing.
3953   SmallVector<AliasSummary *, 64> Aliases;
3954 
3955   // Save the value id for each summary for alias emission.
3956   DenseMap<const GlobalValueSummary *, unsigned> SummaryToValueIdMap;
3957 
3958   SmallVector<uint64_t, 64> NameVals;
3959 
3960   // Set that will be populated during call to writeFunctionTypeMetadataRecords
3961   // with the type ids referenced by this index file.
3962   std::set<GlobalValue::GUID> ReferencedTypeIds;
3963 
3964   // For local linkage, we also emit the original name separately
3965   // immediately after the record.
3966   auto MaybeEmitOriginalName = [&](GlobalValueSummary &S) {
3967     if (!GlobalValue::isLocalLinkage(S.linkage()))
3968       return;
3969     NameVals.push_back(S.getOriginalName());
3970     Stream.EmitRecord(bitc::FS_COMBINED_ORIGINAL_NAME, NameVals);
3971     NameVals.clear();
3972   };
3973 
3974   forEachSummary([&](GVInfo I, bool IsAliasee) {
3975     GlobalValueSummary *S = I.second;
3976     assert(S);
3977 
3978     auto ValueId = getValueId(I.first);
3979     assert(ValueId);
3980     SummaryToValueIdMap[S] = *ValueId;
3981 
3982     // If this is invoked for an aliasee, we want to record the above
3983     // mapping, but then not emit a summary entry (if the aliasee is
3984     // to be imported, we will invoke this separately with IsAliasee=false).
3985     if (IsAliasee)
3986       return;
3987 
3988     if (auto *AS = dyn_cast<AliasSummary>(S)) {
3989       // Will process aliases as a post-pass because the reader wants all
3990       // global to be loaded first.
3991       Aliases.push_back(AS);
3992       return;
3993     }
3994 
3995     if (auto *VS = dyn_cast<GlobalVarSummary>(S)) {
3996       NameVals.push_back(*ValueId);
3997       NameVals.push_back(Index.getModuleId(VS->modulePath()));
3998       NameVals.push_back(getEncodedGVSummaryFlags(VS->flags()));
3999       NameVals.push_back(getEncodedGVarFlags(VS->varflags()));
4000       for (auto &RI : VS->refs()) {
4001         auto RefValueId = getValueId(RI.getGUID());
4002         if (!RefValueId)
4003           continue;
4004         NameVals.push_back(*RefValueId);
4005       }
4006 
4007       // Emit the finished record.
4008       Stream.EmitRecord(bitc::FS_COMBINED_GLOBALVAR_INIT_REFS, NameVals,
4009                         FSModRefsAbbrev);
4010       NameVals.clear();
4011       MaybeEmitOriginalName(*S);
4012       return;
4013     }
4014 
4015     auto *FS = cast<FunctionSummary>(S);
4016     writeFunctionTypeMetadataRecords(Stream, FS);
4017     getReferencedTypeIds(FS, ReferencedTypeIds);
4018 
4019     NameVals.push_back(*ValueId);
4020     NameVals.push_back(Index.getModuleId(FS->modulePath()));
4021     NameVals.push_back(getEncodedGVSummaryFlags(FS->flags()));
4022     NameVals.push_back(FS->instCount());
4023     NameVals.push_back(getEncodedFFlags(FS->fflags()));
4024     NameVals.push_back(FS->entryCount());
4025 
4026     // Fill in below
4027     NameVals.push_back(0); // numrefs
4028     NameVals.push_back(0); // rorefcnt
4029     NameVals.push_back(0); // worefcnt
4030 
4031     unsigned Count = 0, RORefCnt = 0, WORefCnt = 0;
4032     for (auto &RI : FS->refs()) {
4033       auto RefValueId = getValueId(RI.getGUID());
4034       if (!RefValueId)
4035         continue;
4036       NameVals.push_back(*RefValueId);
4037       if (RI.isReadOnly())
4038         RORefCnt++;
4039       else if (RI.isWriteOnly())
4040         WORefCnt++;
4041       Count++;
4042     }
4043     NameVals[6] = Count;
4044     NameVals[7] = RORefCnt;
4045     NameVals[8] = WORefCnt;
4046 
4047     bool HasProfileData = false;
4048     for (auto &EI : FS->calls()) {
4049       HasProfileData |=
4050           EI.second.getHotness() != CalleeInfo::HotnessType::Unknown;
4051       if (HasProfileData)
4052         break;
4053     }
4054 
4055     for (auto &EI : FS->calls()) {
4056       // If this GUID doesn't have a value id, it doesn't have a function
4057       // summary and we don't need to record any calls to it.
4058       GlobalValue::GUID GUID = EI.first.getGUID();
4059       auto CallValueId = getValueId(GUID);
4060       if (!CallValueId) {
4061         // For SamplePGO, the indirect call targets for local functions will
4062         // have its original name annotated in profile. We try to find the
4063         // corresponding PGOFuncName as the GUID.
4064         GUID = Index.getGUIDFromOriginalID(GUID);
4065         if (GUID == 0)
4066           continue;
4067         CallValueId = getValueId(GUID);
4068         if (!CallValueId)
4069           continue;
4070         // The mapping from OriginalId to GUID may return a GUID
4071         // that corresponds to a static variable. Filter it out here.
4072         // This can happen when
4073         // 1) There is a call to a library function which does not have
4074         // a CallValidId;
4075         // 2) There is a static variable with the  OriginalGUID identical
4076         // to the GUID of the library function in 1);
4077         // When this happens, the logic for SamplePGO kicks in and
4078         // the static variable in 2) will be found, which needs to be
4079         // filtered out.
4080         auto *GVSum = Index.getGlobalValueSummary(GUID, false);
4081         if (GVSum &&
4082             GVSum->getSummaryKind() == GlobalValueSummary::GlobalVarKind)
4083           continue;
4084       }
4085       NameVals.push_back(*CallValueId);
4086       if (HasProfileData)
4087         NameVals.push_back(static_cast<uint8_t>(EI.second.Hotness));
4088     }
4089 
4090     unsigned FSAbbrev = (HasProfileData ? FSCallsProfileAbbrev : FSCallsAbbrev);
4091     unsigned Code =
4092         (HasProfileData ? bitc::FS_COMBINED_PROFILE : bitc::FS_COMBINED);
4093 
4094     // Emit the finished record.
4095     Stream.EmitRecord(Code, NameVals, FSAbbrev);
4096     NameVals.clear();
4097     MaybeEmitOriginalName(*S);
4098   });
4099 
4100   for (auto *AS : Aliases) {
4101     auto AliasValueId = SummaryToValueIdMap[AS];
4102     assert(AliasValueId);
4103     NameVals.push_back(AliasValueId);
4104     NameVals.push_back(Index.getModuleId(AS->modulePath()));
4105     NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
4106     auto AliaseeValueId = SummaryToValueIdMap[&AS->getAliasee()];
4107     assert(AliaseeValueId);
4108     NameVals.push_back(AliaseeValueId);
4109 
4110     // Emit the finished record.
4111     Stream.EmitRecord(bitc::FS_COMBINED_ALIAS, NameVals, FSAliasAbbrev);
4112     NameVals.clear();
4113     MaybeEmitOriginalName(*AS);
4114 
4115     if (auto *FS = dyn_cast<FunctionSummary>(&AS->getAliasee()))
4116       getReferencedTypeIds(FS, ReferencedTypeIds);
4117   }
4118 
4119   if (!Index.cfiFunctionDefs().empty()) {
4120     for (auto &S : Index.cfiFunctionDefs()) {
4121       NameVals.push_back(StrtabBuilder.add(S));
4122       NameVals.push_back(S.size());
4123     }
4124     Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DEFS, NameVals);
4125     NameVals.clear();
4126   }
4127 
4128   if (!Index.cfiFunctionDecls().empty()) {
4129     for (auto &S : Index.cfiFunctionDecls()) {
4130       NameVals.push_back(StrtabBuilder.add(S));
4131       NameVals.push_back(S.size());
4132     }
4133     Stream.EmitRecord(bitc::FS_CFI_FUNCTION_DECLS, NameVals);
4134     NameVals.clear();
4135   }
4136 
4137   // Walk the GUIDs that were referenced, and write the
4138   // corresponding type id records.
4139   for (auto &T : ReferencedTypeIds) {
4140     auto TidIter = Index.typeIds().equal_range(T);
4141     for (auto It = TidIter.first; It != TidIter.second; ++It) {
4142       writeTypeIdSummaryRecord(NameVals, StrtabBuilder, It->second.first,
4143                                It->second.second);
4144       Stream.EmitRecord(bitc::FS_TYPE_ID, NameVals);
4145       NameVals.clear();
4146     }
4147   }
4148 
4149   Stream.ExitBlock();
4150 }
4151 
4152 /// Create the "IDENTIFICATION_BLOCK_ID" containing a single string with the
4153 /// current llvm version, and a record for the epoch number.
4154 static void writeIdentificationBlock(BitstreamWriter &Stream) {
4155   Stream.EnterSubblock(bitc::IDENTIFICATION_BLOCK_ID, 5);
4156 
4157   // Write the "user readable" string identifying the bitcode producer
4158   auto Abbv = std::make_shared<BitCodeAbbrev>();
4159   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_STRING));
4160   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4161   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
4162   auto StringAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4163   writeStringRecord(Stream, bitc::IDENTIFICATION_CODE_STRING,
4164                     "LLVM" LLVM_VERSION_STRING, StringAbbrev);
4165 
4166   // Write the epoch version
4167   Abbv = std::make_shared<BitCodeAbbrev>();
4168   Abbv->Add(BitCodeAbbrevOp(bitc::IDENTIFICATION_CODE_EPOCH));
4169   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6));
4170   auto EpochAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4171   SmallVector<unsigned, 1> Vals = {bitc::BITCODE_CURRENT_EPOCH};
4172   Stream.EmitRecord(bitc::IDENTIFICATION_CODE_EPOCH, Vals, EpochAbbrev);
4173   Stream.ExitBlock();
4174 }
4175 
4176 void ModuleBitcodeWriter::writeModuleHash(size_t BlockStartPos) {
4177   // Emit the module's hash.
4178   // MODULE_CODE_HASH: [5*i32]
4179   if (GenerateHash) {
4180     uint32_t Vals[5];
4181     Hasher.update(ArrayRef<uint8_t>((const uint8_t *)&(Buffer)[BlockStartPos],
4182                                     Buffer.size() - BlockStartPos));
4183     StringRef Hash = Hasher.result();
4184     for (int Pos = 0; Pos < 20; Pos += 4) {
4185       Vals[Pos / 4] = support::endian::read32be(Hash.data() + Pos);
4186     }
4187 
4188     // Emit the finished record.
4189     Stream.EmitRecord(bitc::MODULE_CODE_HASH, Vals);
4190 
4191     if (ModHash)
4192       // Save the written hash value.
4193       llvm::copy(Vals, std::begin(*ModHash));
4194   }
4195 }
4196 
4197 void ModuleBitcodeWriter::write() {
4198   writeIdentificationBlock(Stream);
4199 
4200   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4201   size_t BlockStartPos = Buffer.size();
4202 
4203   writeModuleVersion();
4204 
4205   // Emit blockinfo, which defines the standard abbreviations etc.
4206   writeBlockInfo();
4207 
4208   // Emit information describing all of the types in the module.
4209   writeTypeTable();
4210 
4211   // Emit information about attribute groups.
4212   writeAttributeGroupTable();
4213 
4214   // Emit information about parameter attributes.
4215   writeAttributeTable();
4216 
4217   writeComdats();
4218 
4219   // Emit top-level description of module, including target triple, inline asm,
4220   // descriptors for global variables, and function prototype info.
4221   writeModuleInfo();
4222 
4223   // Emit constants.
4224   writeModuleConstants();
4225 
4226   // Emit metadata kind names.
4227   writeModuleMetadataKinds();
4228 
4229   // Emit metadata.
4230   writeModuleMetadata();
4231 
4232   // Emit module-level use-lists.
4233   if (VE.shouldPreserveUseListOrder())
4234     writeUseListBlock(nullptr);
4235 
4236   writeOperandBundleTags();
4237   writeSyncScopeNames();
4238 
4239   // Emit function bodies.
4240   DenseMap<const Function *, uint64_t> FunctionToBitcodeIndex;
4241   for (Module::const_iterator F = M.begin(), E = M.end(); F != E; ++F)
4242     if (!F->isDeclaration())
4243       writeFunction(*F, FunctionToBitcodeIndex);
4244 
4245   // Need to write after the above call to WriteFunction which populates
4246   // the summary information in the index.
4247   if (Index)
4248     writePerModuleGlobalValueSummary();
4249 
4250   writeGlobalValueSymbolTable(FunctionToBitcodeIndex);
4251 
4252   writeModuleHash(BlockStartPos);
4253 
4254   Stream.ExitBlock();
4255 }
4256 
4257 static void writeInt32ToBuffer(uint32_t Value, SmallVectorImpl<char> &Buffer,
4258                                uint32_t &Position) {
4259   support::endian::write32le(&Buffer[Position], Value);
4260   Position += 4;
4261 }
4262 
4263 /// If generating a bc file on darwin, we have to emit a
4264 /// header and trailer to make it compatible with the system archiver.  To do
4265 /// this we emit the following header, and then emit a trailer that pads the
4266 /// file out to be a multiple of 16 bytes.
4267 ///
4268 /// struct bc_header {
4269 ///   uint32_t Magic;         // 0x0B17C0DE
4270 ///   uint32_t Version;       // Version, currently always 0.
4271 ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
4272 ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
4273 ///   uint32_t CPUType;       // CPU specifier.
4274 ///   ... potentially more later ...
4275 /// };
4276 static void emitDarwinBCHeaderAndTrailer(SmallVectorImpl<char> &Buffer,
4277                                          const Triple &TT) {
4278   unsigned CPUType = ~0U;
4279 
4280   // Match x86_64-*, i[3-9]86-*, powerpc-*, powerpc64-*, arm-*, thumb-*,
4281   // armv[0-9]-*, thumbv[0-9]-*, armv5te-*, or armv6t2-*. The CPUType is a magic
4282   // number from /usr/include/mach/machine.h.  It is ok to reproduce the
4283   // specific constants here because they are implicitly part of the Darwin ABI.
4284   enum {
4285     DARWIN_CPU_ARCH_ABI64      = 0x01000000,
4286     DARWIN_CPU_TYPE_X86        = 7,
4287     DARWIN_CPU_TYPE_ARM        = 12,
4288     DARWIN_CPU_TYPE_POWERPC    = 18
4289   };
4290 
4291   Triple::ArchType Arch = TT.getArch();
4292   if (Arch == Triple::x86_64)
4293     CPUType = DARWIN_CPU_TYPE_X86 | DARWIN_CPU_ARCH_ABI64;
4294   else if (Arch == Triple::x86)
4295     CPUType = DARWIN_CPU_TYPE_X86;
4296   else if (Arch == Triple::ppc)
4297     CPUType = DARWIN_CPU_TYPE_POWERPC;
4298   else if (Arch == Triple::ppc64)
4299     CPUType = DARWIN_CPU_TYPE_POWERPC | DARWIN_CPU_ARCH_ABI64;
4300   else if (Arch == Triple::arm || Arch == Triple::thumb)
4301     CPUType = DARWIN_CPU_TYPE_ARM;
4302 
4303   // Traditional Bitcode starts after header.
4304   assert(Buffer.size() >= BWH_HeaderSize &&
4305          "Expected header size to be reserved");
4306   unsigned BCOffset = BWH_HeaderSize;
4307   unsigned BCSize = Buffer.size() - BWH_HeaderSize;
4308 
4309   // Write the magic and version.
4310   unsigned Position = 0;
4311   writeInt32ToBuffer(0x0B17C0DE, Buffer, Position);
4312   writeInt32ToBuffer(0, Buffer, Position); // Version.
4313   writeInt32ToBuffer(BCOffset, Buffer, Position);
4314   writeInt32ToBuffer(BCSize, Buffer, Position);
4315   writeInt32ToBuffer(CPUType, Buffer, Position);
4316 
4317   // If the file is not a multiple of 16 bytes, insert dummy padding.
4318   while (Buffer.size() & 15)
4319     Buffer.push_back(0);
4320 }
4321 
4322 /// Helper to write the header common to all bitcode files.
4323 static void writeBitcodeHeader(BitstreamWriter &Stream) {
4324   // Emit the file header.
4325   Stream.Emit((unsigned)'B', 8);
4326   Stream.Emit((unsigned)'C', 8);
4327   Stream.Emit(0x0, 4);
4328   Stream.Emit(0xC, 4);
4329   Stream.Emit(0xE, 4);
4330   Stream.Emit(0xD, 4);
4331 }
4332 
4333 BitcodeWriter::BitcodeWriter(SmallVectorImpl<char> &Buffer)
4334     : Buffer(Buffer), Stream(new BitstreamWriter(Buffer)) {
4335   writeBitcodeHeader(*Stream);
4336 }
4337 
4338 BitcodeWriter::~BitcodeWriter() { assert(WroteStrtab); }
4339 
4340 void BitcodeWriter::writeBlob(unsigned Block, unsigned Record, StringRef Blob) {
4341   Stream->EnterSubblock(Block, 3);
4342 
4343   auto Abbv = std::make_shared<BitCodeAbbrev>();
4344   Abbv->Add(BitCodeAbbrevOp(Record));
4345   Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Blob));
4346   auto AbbrevNo = Stream->EmitAbbrev(std::move(Abbv));
4347 
4348   Stream->EmitRecordWithBlob(AbbrevNo, ArrayRef<uint64_t>{Record}, Blob);
4349 
4350   Stream->ExitBlock();
4351 }
4352 
4353 void BitcodeWriter::writeSymtab() {
4354   assert(!WroteStrtab && !WroteSymtab);
4355 
4356   // If any module has module-level inline asm, we will require a registered asm
4357   // parser for the target so that we can create an accurate symbol table for
4358   // the module.
4359   for (Module *M : Mods) {
4360     if (M->getModuleInlineAsm().empty())
4361       continue;
4362 
4363     std::string Err;
4364     const Triple TT(M->getTargetTriple());
4365     const Target *T = TargetRegistry::lookupTarget(TT.str(), Err);
4366     if (!T || !T->hasMCAsmParser())
4367       return;
4368   }
4369 
4370   WroteSymtab = true;
4371   SmallVector<char, 0> Symtab;
4372   // The irsymtab::build function may be unable to create a symbol table if the
4373   // module is malformed (e.g. it contains an invalid alias). Writing a symbol
4374   // table is not required for correctness, but we still want to be able to
4375   // write malformed modules to bitcode files, so swallow the error.
4376   if (Error E = irsymtab::build(Mods, Symtab, StrtabBuilder, Alloc)) {
4377     consumeError(std::move(E));
4378     return;
4379   }
4380 
4381   writeBlob(bitc::SYMTAB_BLOCK_ID, bitc::SYMTAB_BLOB,
4382             {Symtab.data(), Symtab.size()});
4383 }
4384 
4385 void BitcodeWriter::writeStrtab() {
4386   assert(!WroteStrtab);
4387 
4388   std::vector<char> Strtab;
4389   StrtabBuilder.finalizeInOrder();
4390   Strtab.resize(StrtabBuilder.getSize());
4391   StrtabBuilder.write((uint8_t *)Strtab.data());
4392 
4393   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB,
4394             {Strtab.data(), Strtab.size()});
4395 
4396   WroteStrtab = true;
4397 }
4398 
4399 void BitcodeWriter::copyStrtab(StringRef Strtab) {
4400   writeBlob(bitc::STRTAB_BLOCK_ID, bitc::STRTAB_BLOB, Strtab);
4401   WroteStrtab = true;
4402 }
4403 
4404 void BitcodeWriter::writeModule(const Module &M,
4405                                 bool ShouldPreserveUseListOrder,
4406                                 const ModuleSummaryIndex *Index,
4407                                 bool GenerateHash, ModuleHash *ModHash) {
4408   assert(!WroteStrtab);
4409 
4410   // The Mods vector is used by irsymtab::build, which requires non-const
4411   // Modules in case it needs to materialize metadata. But the bitcode writer
4412   // requires that the module is materialized, so we can cast to non-const here,
4413   // after checking that it is in fact materialized.
4414   assert(M.isMaterialized());
4415   Mods.push_back(const_cast<Module *>(&M));
4416 
4417   ModuleBitcodeWriter ModuleWriter(M, Buffer, StrtabBuilder, *Stream,
4418                                    ShouldPreserveUseListOrder, Index,
4419                                    GenerateHash, ModHash);
4420   ModuleWriter.write();
4421 }
4422 
4423 void BitcodeWriter::writeIndex(
4424     const ModuleSummaryIndex *Index,
4425     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4426   IndexBitcodeWriter IndexWriter(*Stream, StrtabBuilder, *Index,
4427                                  ModuleToSummariesForIndex);
4428   IndexWriter.write();
4429 }
4430 
4431 /// Write the specified module to the specified output stream.
4432 void llvm::WriteBitcodeToFile(const Module &M, raw_ostream &Out,
4433                               bool ShouldPreserveUseListOrder,
4434                               const ModuleSummaryIndex *Index,
4435                               bool GenerateHash, ModuleHash *ModHash) {
4436   SmallVector<char, 0> Buffer;
4437   Buffer.reserve(256*1024);
4438 
4439   // If this is darwin or another generic macho target, reserve space for the
4440   // header.
4441   Triple TT(M.getTargetTriple());
4442   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4443     Buffer.insert(Buffer.begin(), BWH_HeaderSize, 0);
4444 
4445   BitcodeWriter Writer(Buffer);
4446   Writer.writeModule(M, ShouldPreserveUseListOrder, Index, GenerateHash,
4447                      ModHash);
4448   Writer.writeSymtab();
4449   Writer.writeStrtab();
4450 
4451   if (TT.isOSDarwin() || TT.isOSBinFormatMachO())
4452     emitDarwinBCHeaderAndTrailer(Buffer, TT);
4453 
4454   // Write the generated bitstream to "Out".
4455   Out.write((char*)&Buffer.front(), Buffer.size());
4456 }
4457 
4458 void IndexBitcodeWriter::write() {
4459   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4460 
4461   writeModuleVersion();
4462 
4463   // Write the module paths in the combined index.
4464   writeModStrings();
4465 
4466   // Write the summary combined index records.
4467   writeCombinedGlobalValueSummary();
4468 
4469   Stream.ExitBlock();
4470 }
4471 
4472 // Write the specified module summary index to the given raw output stream,
4473 // where it will be written in a new bitcode block. This is used when
4474 // writing the combined index file for ThinLTO. When writing a subset of the
4475 // index for a distributed backend, provide a \p ModuleToSummariesForIndex map.
4476 void llvm::WriteIndexToFile(
4477     const ModuleSummaryIndex &Index, raw_ostream &Out,
4478     const std::map<std::string, GVSummaryMapTy> *ModuleToSummariesForIndex) {
4479   SmallVector<char, 0> Buffer;
4480   Buffer.reserve(256 * 1024);
4481 
4482   BitcodeWriter Writer(Buffer);
4483   Writer.writeIndex(&Index, ModuleToSummariesForIndex);
4484   Writer.writeStrtab();
4485 
4486   Out.write((char *)&Buffer.front(), Buffer.size());
4487 }
4488 
4489 namespace {
4490 
4491 /// Class to manage the bitcode writing for a thin link bitcode file.
4492 class ThinLinkBitcodeWriter : public ModuleBitcodeWriterBase {
4493   /// ModHash is for use in ThinLTO incremental build, generated while writing
4494   /// the module bitcode file.
4495   const ModuleHash *ModHash;
4496 
4497 public:
4498   ThinLinkBitcodeWriter(const Module &M, StringTableBuilder &StrtabBuilder,
4499                         BitstreamWriter &Stream,
4500                         const ModuleSummaryIndex &Index,
4501                         const ModuleHash &ModHash)
4502       : ModuleBitcodeWriterBase(M, StrtabBuilder, Stream,
4503                                 /*ShouldPreserveUseListOrder=*/false, &Index),
4504         ModHash(&ModHash) {}
4505 
4506   void write();
4507 
4508 private:
4509   void writeSimplifiedModuleInfo();
4510 };
4511 
4512 } // end anonymous namespace
4513 
4514 // This function writes a simpilified module info for thin link bitcode file.
4515 // It only contains the source file name along with the name(the offset and
4516 // size in strtab) and linkage for global values. For the global value info
4517 // entry, in order to keep linkage at offset 5, there are three zeros used
4518 // as padding.
4519 void ThinLinkBitcodeWriter::writeSimplifiedModuleInfo() {
4520   SmallVector<unsigned, 64> Vals;
4521   // Emit the module's source file name.
4522   {
4523     StringEncoding Bits = getStringEncoding(M.getSourceFileName());
4524     BitCodeAbbrevOp AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8);
4525     if (Bits == SE_Char6)
4526       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Char6);
4527     else if (Bits == SE_Fixed7)
4528       AbbrevOpToUse = BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7);
4529 
4530     // MODULE_CODE_SOURCE_FILENAME: [namechar x N]
4531     auto Abbv = std::make_shared<BitCodeAbbrev>();
4532     Abbv->Add(BitCodeAbbrevOp(bitc::MODULE_CODE_SOURCE_FILENAME));
4533     Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
4534     Abbv->Add(AbbrevOpToUse);
4535     unsigned FilenameAbbrev = Stream.EmitAbbrev(std::move(Abbv));
4536 
4537     for (const auto P : M.getSourceFileName())
4538       Vals.push_back((unsigned char)P);
4539 
4540     Stream.EmitRecord(bitc::MODULE_CODE_SOURCE_FILENAME, Vals, FilenameAbbrev);
4541     Vals.clear();
4542   }
4543 
4544   // Emit the global variable information.
4545   for (const GlobalVariable &GV : M.globals()) {
4546     // GLOBALVAR: [strtab offset, strtab size, 0, 0, 0, linkage]
4547     Vals.push_back(StrtabBuilder.add(GV.getName()));
4548     Vals.push_back(GV.getName().size());
4549     Vals.push_back(0);
4550     Vals.push_back(0);
4551     Vals.push_back(0);
4552     Vals.push_back(getEncodedLinkage(GV));
4553 
4554     Stream.EmitRecord(bitc::MODULE_CODE_GLOBALVAR, Vals);
4555     Vals.clear();
4556   }
4557 
4558   // Emit the function proto information.
4559   for (const Function &F : M) {
4560     // FUNCTION:  [strtab offset, strtab size, 0, 0, 0, linkage]
4561     Vals.push_back(StrtabBuilder.add(F.getName()));
4562     Vals.push_back(F.getName().size());
4563     Vals.push_back(0);
4564     Vals.push_back(0);
4565     Vals.push_back(0);
4566     Vals.push_back(getEncodedLinkage(F));
4567 
4568     Stream.EmitRecord(bitc::MODULE_CODE_FUNCTION, Vals);
4569     Vals.clear();
4570   }
4571 
4572   // Emit the alias information.
4573   for (const GlobalAlias &A : M.aliases()) {
4574     // ALIAS: [strtab offset, strtab size, 0, 0, 0, linkage]
4575     Vals.push_back(StrtabBuilder.add(A.getName()));
4576     Vals.push_back(A.getName().size());
4577     Vals.push_back(0);
4578     Vals.push_back(0);
4579     Vals.push_back(0);
4580     Vals.push_back(getEncodedLinkage(A));
4581 
4582     Stream.EmitRecord(bitc::MODULE_CODE_ALIAS, Vals);
4583     Vals.clear();
4584   }
4585 
4586   // Emit the ifunc information.
4587   for (const GlobalIFunc &I : M.ifuncs()) {
4588     // IFUNC: [strtab offset, strtab size, 0, 0, 0, linkage]
4589     Vals.push_back(StrtabBuilder.add(I.getName()));
4590     Vals.push_back(I.getName().size());
4591     Vals.push_back(0);
4592     Vals.push_back(0);
4593     Vals.push_back(0);
4594     Vals.push_back(getEncodedLinkage(I));
4595 
4596     Stream.EmitRecord(bitc::MODULE_CODE_IFUNC, Vals);
4597     Vals.clear();
4598   }
4599 }
4600 
4601 void ThinLinkBitcodeWriter::write() {
4602   Stream.EnterSubblock(bitc::MODULE_BLOCK_ID, 3);
4603 
4604   writeModuleVersion();
4605 
4606   writeSimplifiedModuleInfo();
4607 
4608   writePerModuleGlobalValueSummary();
4609 
4610   // Write module hash.
4611   Stream.EmitRecord(bitc::MODULE_CODE_HASH, ArrayRef<uint32_t>(*ModHash));
4612 
4613   Stream.ExitBlock();
4614 }
4615 
4616 void BitcodeWriter::writeThinLinkBitcode(const Module &M,
4617                                          const ModuleSummaryIndex &Index,
4618                                          const ModuleHash &ModHash) {
4619   assert(!WroteStrtab);
4620 
4621   // The Mods vector is used by irsymtab::build, which requires non-const
4622   // Modules in case it needs to materialize metadata. But the bitcode writer
4623   // requires that the module is materialized, so we can cast to non-const here,
4624   // after checking that it is in fact materialized.
4625   assert(M.isMaterialized());
4626   Mods.push_back(const_cast<Module *>(&M));
4627 
4628   ThinLinkBitcodeWriter ThinLinkWriter(M, StrtabBuilder, *Stream, Index,
4629                                        ModHash);
4630   ThinLinkWriter.write();
4631 }
4632 
4633 // Write the specified thin link bitcode file to the given raw output stream,
4634 // where it will be written in a new bitcode block. This is used when
4635 // writing the per-module index file for ThinLTO.
4636 void llvm::WriteThinLinkBitcodeToFile(const Module &M, raw_ostream &Out,
4637                                       const ModuleSummaryIndex &Index,
4638                                       const ModuleHash &ModHash) {
4639   SmallVector<char, 0> Buffer;
4640   Buffer.reserve(256 * 1024);
4641 
4642   BitcodeWriter Writer(Buffer);
4643   Writer.writeThinLinkBitcode(M, Index, ModHash);
4644   Writer.writeSymtab();
4645   Writer.writeStrtab();
4646 
4647   Out.write((char *)&Buffer.front(), Buffer.size());
4648 }
4649